WorldWideScience

Sample records for surface reflectance quality

  1. Quality Assessment of Landsat Surface Reflectance Products Using MODIS Data

    Science.gov (United States)

    Feng, Min; Huang, Chengquan; Channan, Saurabh; Vermote, Eric; Masek, Jeffrey G.; Townshend, John R.

    2012-01-01

    Surface reflectance adjusted for atmospheric effects is a primary input for land cover change detection and for developing many higher level surface geophysical parameters. With the development of automated atmospheric correction algorithms, it is now feasible to produce large quantities of surface reflectance products using Landsat images. Validation of these products requires in situ measurements, which either do not exist or are difficult to obtain for most Landsat images. The surface reflectance products derived using data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), however, have been validated more comprehensively. Because the MODIS on the Terra platform and the Landsat 7 are only half an hour apart following the same orbit, and each of the 6 Landsat spectral bands overlaps with a MODIS band, good agreements between MODIS and Landsat surface reflectance values can be considered indicators of the reliability of the Landsat products, while disagreements may suggest potential quality problems that need to be further investigated. Here we develop a system called Landsat-MODIS Consistency Checking System (LMCCS). This system automatically matches Landsat data with MODIS observations acquired on the same date over the same locations and uses them to calculate a set of agreement metrics. To maximize its portability, Java and open-source libraries were used in developing this system, and object-oriented programming (OOP) principles were followed to make it more flexible for future expansion. As a highly automated system designed to run as a stand-alone package or as a component of other Landsat data processing systems, this system can be used to assess the quality of essentially every Landsat surface reflectance image where spatially and temporally matching MODIS data are available. The effectiveness of this system was demonstrated using it to assess preliminary surface reflectance products derived using the Global Land Survey (GLS) Landsat

  2. Landsat surface reflectance quality assurance extraction (version 1.7)

    Science.gov (United States)

    Jones, J.W.; Starbuck, M.J.; Jenkerson, Calli B.

    2013-01-01

    The U.S. Geological Survey (USGS) Land Remote Sensing Program is developing an operational capability to produce Climate Data Records (CDRs) and Essential Climate Variables (ECVs) from the Landsat Archive to support a wide variety of science and resource management activities from regional to global scale. The USGS Earth Resources Observation and Science (EROS) Center is charged with prototyping systems and software to generate these high-level data products. Various USGS Geographic Science Centers are charged with particular ECV algorithm development and (or) selection as well as the evaluation and application demonstration of various USGS CDRs and ECVs. Because it is a foundation for many other ECVs, the first CDR in development is the Landsat Surface Reflectance Product (LSRP). The LSRP incorporates data quality information in a bit-packed structure that is not readily accessible without postprocessing services performed by the user. This document describes two general methods of LSRP quality-data extraction for use in image processing systems. Helpful hints for the installation and use of software originally developed for manipulation of Hierarchical Data Format (HDF) produced through the National Aeronautics and Space Administration (NASA) Earth Observing System are first provided for users who wish to extract quality data into separate HDF files. Next, steps follow to incorporate these extracted data into an image processing system. Finally, an alternative example is illustrated in which the data are extracted within a particular image processing system.

  3. High quality broadband spatial reflections of slow Rayleigh surface acoustic waves modulated by a graded grooved surface

    KAUST Repository

    Xu, Yanlong

    2015-01-21

    We report high quality broadband spatial reflections of Rayleigh surface acoustic waves (SAWs) through a graded grooved surface. High quality means that no wave is allowed to transmit and the incident wave is nearly all reflected to the input side. The graded grooved surface is structured by drilling one dimensional array of graded grooves with increased depths on a flat surface. We investigate SAW dispersion relations, wave field distribution at several typical SAW wavelengths, and time evolution of a Gaussian pulse through the graded grooved surface. Results show that the input broadband Rayleigh SAWs can be slowed, spatially enhanced and stopped, and finally reflected to the input side. The study suggests that engraving the flat surface can be used as an efficient and economical way to manipulate Rayleigh SAWs, which has potential application in novel SAW devices such as filters, reflectors, sensors, energy harvesters, and diodes.

  4. High quality broadband spatial reflections of slow Rayleigh surface acoustic waves modulated by a graded grooved surface

    KAUST Repository

    Xu, Yanlong; Peng, Pai

    2015-01-01

    . The graded grooved surface is structured by drilling one dimensional array of graded grooves with increased depths on a flat surface. We investigate SAW dispersion relations, wave field distribution at several typical SAW wavelengths, and time evolution of a

  5. On automatic visual inspection of reflective surfaces

    DEFF Research Database (Denmark)

    Kulmann, Lionel

    1995-01-01

    surfaces, providing new and exciting applications subject to automated visual inspection. Several contextual features have been surveyed along with introduction of novel methods to perform data-dependent enhancement of local surface appearance . Morphological methods have been described and utilized......This thesis descrbes different methods to perform automatic visual inspection of reflective manufactured products, with the aim of increasing productivity, reduce cost and improve the quality level of the production. We investigate two different systems performing automatic visual inspection....... The first is the inspection of highly reflective aluminum sheets, used by the Danish company Bang & Olufsen, as a part of the exterior design and general appearance of their audio and video products. The second is the inspection of IBM hard disk read/write heads for defects during manufacturing. We have...

  6. Influence of particle and surface quality on the vitrinite reflectance of dispersed organic matter: Comparative exercise using data from the qualifying system for reflectance analysis working group of ICCP

    Science.gov (United States)

    Borrego, A.G.; Araujo, C.V.; Balke, A.; Cardott, B.; Cook, A.C.; David, P.; Flores, D.; Hamor-Vido, M.; Hiltmann, W.; Kalkreuth, W.; Koch, J.; Kommeren, C.J.; Kus, J.; Ligouis, B.; Marques, M.; Mendonca, Filho J.G.; Misz, M.; Oliveira, L.; Pickel, W.; Reimer, K.; Ranasinghe, P.; Suarez-Ruiz, I.; Vieth, A.

    2006-01-01

    The development of a qualifying system for reflectance analysis has been the scope of a working group within the International Committee for Coal and Organic Petrology (ICCP) since 1999, when J. Koch presented a system to qualify vitrinite particles according to their size, proximity to bright components and homogeneity of the surface. After some years of work aimed at improving the classification system using photomicrographs, it was decided to run a round robin exercise on microscopy samples. The classification system tested consists of three qualifiers ranging from excellent to low quality vitrinites with an additional option for unsuitable vitrinites. This paper reports on the results obtained by 22 analysts who were asked to measure random reflectance readings on vitrinite particles assigning to each reading a qualifier. Four samples containing different organic matter types and a variety of vitrinite occurrences have been analysed. Results indicated that the reflectance of particles classified as excellent, good or poor compared to the total average reflectance did not show trends to be systematically lower or higher for the four samples analysed. The differences in reflectance between the qualifiers for any given sample were lower than the scatter of vitrinite reflectance among participants. Overall, satisfactory results were obtained in determining the reflectance of vitrinite in the four samples analysed. This was so for samples having abundant and easy to identify vitrinites (higher plant-derived organic matter) as well as for samples with scarce and difficult to identify particles (samples with dominant marine-derived organic matter). The highest discrepancies were found for the organic-rich oil shales where the selection of the vitrinite population to measure proved to be particularly difficult. Special instructions should be provided for the analysis of this sort of samples. The certainty of identification of the vitrinite associated with the vitrinite

  7. A climatology of visible surface reflectance spectra

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. - Highlights: • Our goals was visible surface reflectance for satellite trace gas measurements. • Captured the range of surface reflectance spectra through EOF analysis. • Used satellite surface reflectance products for each given scene to anchor EOFs. • Generated a climatology of time/geometry dependent surface reflectance spectra. • Demonstrated potential to

  8. A Bayesian Reflection on Surfaces

    Directory of Open Access Journals (Sweden)

    David R. Wolf

    1999-10-01

    Full Text Available Abstract: The topic of this paper is a novel Bayesian continuous-basis field representation and inference framework. Within this paper several problems are solved: The maximally informative inference of continuous-basis fields, that is where the basis for the field is itself a continuous object and not representable in a finite manner; the tradeoff between accuracy of representation in terms of information learned, and memory or storage capacity in bits; the approximation of probability distributions so that a maximal amount of information about the object being inferred is preserved; an information theoretic justification for multigrid methodology. The maximally informative field inference framework is described in full generality and denoted the Generalized Kalman Filter. The Generalized Kalman Filter allows the update of field knowledge from previous knowledge at any scale, and new data, to new knowledge at any other scale. An application example instance, the inference of continuous surfaces from measurements (for example, camera image data, is presented.

  9. Reflection properties of road surfaces. Contribution to OECD Scientific Expert Group AC4 on Road Surface Characteristics.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1983-01-01

    Photometric characteristics of road surfaces are dealt with. Representation of reflection properties in public lighting; quality criteria of road lighting installations; classification of road surfaces; the relation between reflection characteristics and other properties of road pavements in public

  10. 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...... zone the measurements may deriveparameters as sea surface roughness, winds, waves, heights and tilts from the spectral measurements. Previous measurements from the top of mountains and airplanes have shown such results leading.The coming satellite missions, CYGNSS, COSMIC-2, and GEROS...

  11. Use of reflective surfaces on roadway embankment

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Doré, Guy

    2007-01-01

    adherence characteristics for roadway use. In Kangerlussuaq Airport, western Greenland, ground-penetrating radar (GPR) has been used to compare the variation of the frost table underneath a normal black asphalt surface and a more reflective surface (white paint). The GPR results have shown a clear...

  12. Measuring Light Reflectance of BGO Crystal Surfaces

    Science.gov (United States)

    Janecek, Martin; Moses, William W.

    2008-10-01

    A scintillating crystal's surface reflectance has to be well understood in order to accurately predict and optimize the crystal's light collection through Monte Carlo simulations. In this paper, we measure the inner surface reflectance properties for BGO. The measurements include BGO crystals with a mechanically polished surface, rough-cut surface, and chemically etched surface, and with various reflectors attached, both air-coupled and with coupling compound. The measurements are performed with a laser aimed at the center of a hemispherical shaped BGO crystal. The hemispherical shape eliminates any non-perpendicular angles for light entering and exiting the crystal. The reflected light is collected with an array of photodiodes. The laser can be set at an arbitrary angle, and the photodiode array is rotated to fully cover 2pi of solid angle. The current produced in the photodiodes is readout with a digital multimeter connected through a multiplexer. The two rows of photodiodes achieve 5-degree by 4-degree resolution, and the current measurement has a dynamic range of 105:1. The acquired data was not described by the commonly assumed linear combination of specular and diffuse (Lambertian) distributions, except for a very few surfaces. Surface roughness proved to be the most important parameter when choosing crystal setup. The reflector choice was of less importance and of almost no consequence for rough-cut surfaces. Pure specular reflection distribution for all incidence angles was measured for polished surfaces with VM2000 film, while the most Lambertian distribution for any surface finish was measured for titanium dioxide paint. The distributions acquired in this paper will be used to create more accurate Monte Carlo models for light reflection distribution within BGO crystals.

  13. X-ray reflectivity and surface roughness

    International Nuclear Information System (INIS)

    Ocko, B.M.

    1988-01-01

    Since the advent of high brightness synchrotron radiation sources there has been a phenomenal growth in the use of x-rays as a probe of surface structure. The technique of x-ray reflectivity is particularly relevant to electrochemists since it is capable of probing the structure normal to an electrode surface in situ. In this paper the theoretical framework for x-ray reflectivity is reviewed and the results from previous non-electrochemistry measurements are summarized. These measurements are from the liquid/air interface (CCl 4 ), the metal crystal vacuum interface (Au(100)), and from the liquid/solid interface(liquid crystal/silicon). 34 refs., 5 figs

  14. Surface composition of Mercury from reflectance spectrophotometry

    Science.gov (United States)

    Vilas, Faith

    1988-01-01

    The controversies surrounding the existing spectra of Mercury are discussed together with the various implications for interpretations of Mercury's surface composition. Special attention is given to the basic procedure used for reducing reflectance spectrophotometry data, the factors that must be accounted for in the reduction of these data, and the methodology for defining the portion of the surface contributing the greatest amount of light to an individual spectrum. The application of these methodologies to Mercury's spectra is presented.

  15. Reflectance spectroscopy and asteroid surface mineralogy

    International Nuclear Information System (INIS)

    Gaffey, M.J.; Bell, J.F.; Cruikshank, D.P.

    1989-01-01

    Information available from reflectance spectroscopy on the surface mineralogy of asteroids is discussed. Current spectral interpretive procedures used in the investigations of asteroid mineralogy are described. Present understanding of the nature and history of asteroids is discussed together with some still unresolved issues such as the source of ordinary chondrites. 100 refs

  16. ASTER L2 Surface Reflectance SWIR and ASTER L2 Surface Reflectance VNIR V003

    Data.gov (United States)

    National Aeronautics and Space Administration — The ASTER L2 Surface Reflectance is a multi-file product that contains atmospherically corrected data for both the Visible Near-Infrared (VNIR) and Shortwave...

  17. 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.

  18. Remote measurement of surface roughness, surface reflectance, and body reflectance with LiDAR.

    Science.gov (United States)

    Li, Xiaolu; Liang, Yu

    2015-10-20

    Light detection and ranging (LiDAR) intensity data are attracting increasing attention because of the great potential for use of such data in a variety of remote sensing applications. To fully investigate the data potential for target classification and identification, we carried out a series of experiments with typical urban building materials and employed our reconstructed built-in-lab LiDAR system. Received intensity data were analyzed on the basis of the derived bidirectional reflectance distribution function (BRDF) model and the established integration method. With an improved fitting algorithm, parameters involved in the BRDF model can be obtained to depict the surface characteristics. One of these parameters related to surface roughness was converted to a most used roughness parameter, the arithmetical mean deviation of the roughness profile (Ra), which can be used to validate the feasibility of the BRDF model in surface characterizations and performance evaluations.

  19. The differential equation of an arbitrary reflecting surface

    Science.gov (United States)

    Melka, Richard F.; Berrettini, Vincent D.; Yousif, Hashim A.

    2018-05-01

    A differential equation describing the reflection of a light ray incident upon an arbitrary reflecting surface is obtained using the law of reflection. The derived equation is written in terms of a parameter and the value of this parameter determines the nature of the reflecting surface. Under various parametric constraints, the solution of the differential equation leads to the various conic surfaces but is not generally solvable. In addition, the dynamics of the light reflections from the conic surfaces are executed in the Mathematica software. Our derivation is the converse of the traditional approach and our analysis assumes a relation between the object distance and the image distance. This leads to the differential equation of the reflecting surface.

  20. Critical reflection activation analysis - a new near-surface probe

    International Nuclear Information System (INIS)

    Gunn, J.M.F.; Trohidou, K.N.

    1988-09-01

    We propose a new surface analytic technique, Critical Reflection Activation Analysis (CRAA). This technique allows accurate depth profiling of impurities ≤ 100A beneath a surface. The depth profile of the impurity is simply related to the induced activity as a function of the angle of reflection. We argue that the technique is practical and estimate its accuracy. (author)

  1. Infrared spectral reflectances of asteroid surfaces

    Science.gov (United States)

    Larson, H. P.; Veeder, G. J.

    1979-01-01

    This review compares the types of compositional information produced by three complementary techniques used in infrared observations of asteroid surfaces: broadband JHKL photometry, narrow band photometry, and multiplex spectroscopy. The high information content of these infrared observations permits definitive interpretations of asteroid surface compositions in terms of the major meteoritic minerals (olivine, pyroxene, plagioclase feldspar, hydrous silicates, and metallic Ni-Fe). These studies emphasize the individuality of asteroid surface compositions, the inadequacy of simple comparisons with spectra of meteorites, and the need to coordinate spectral measurements of all types to optimize diagnostic capabilities.

  2. Computation of Mach reflection from rigid and yielding surfaces

    International Nuclear Information System (INIS)

    Buckingham, A.C.; Wilson, S.S.

    1976-01-01

    The present discussion centers on a theoretical description of one aspect of the irregular or Mach reflection from solid surfaces. The discussion is restricted to analytical considerations and some preliminary results using model approximations to the surface interaction phenomena. Currently, full numerical simulations of the irregular reflection surface interaction dynamics have not been obtained since the method is still under development. Discussion of the numerical method is, therefore, restricted to some special procedures for the gas-solid surface boundary dynamics. The discussion is divided into an introductory section briefly describing a particular Mach reflection process. Subsequently, some of the considerations on boundary conditions are submitted for numerical treatment of the gas-solid interface. Analysis and discussion of a yielding solid surface subjected to impulsive loading from an intense gas shock wave follows. This is used as a guide for the development of the numerical procedure. Mach reflection processes are then briefly reviewed with special attention for similitude and singular perturbation features

  3. Zerodur polishing process for high surface quality and high efficiency

    International Nuclear Information System (INIS)

    Tesar, A.; Fuchs, B.

    1992-08-01

    Zerodur is a glass-ceramic composite importance in applications where temperature instabilities influence optical and mechanical performance, such as in earthbound and spaceborne telescope mirror substrates. Polished Zerodur surfaces of high quality have been required for laser gyro mirrors. Polished surface quality of substrates affects performance of high reflection coatings. Thus, the interest in improving Zerodur polished surface quality has become more general. Beyond eliminating subsurface damage, high quality surfaces are produced by reducing the amount of hydrated material redeposited on the surface during polishing. With the proper control of polishing parameters, such surfaces exhibit roughnesses of < l Angstrom rms. Zerodur polishing was studied to recommend a high surface quality polishing process which could be easily adapted to standard planetary continuous polishing machines and spindles. This summary contains information on a polishing process developed at LLNL which reproducibly provides high quality polished Zerodur surfaces at very high polishing efficiencies

  4. A Method of Retrieving BRDF from Surface-Reflected Radiance Using Decoupling of Atmospheric Radiative Transfer and Surface Reflection

    Directory of Open Access Journals (Sweden)

    Alexander Radkevich

    2018-04-01

    Full Text Available Bi-directional reflection distribution function (BRDF defines anisotropy of the surface reflection. It is required to specify the boundary condition for radiative transfer (RT modeling used in aerosol retrievals, cloud retrievals, atmospheric modeling, and other applications. Ground based measurements of reflected radiance draw increasing attention as a source of information about anisotropy of surface reflection. Derivation of BRDF from surface radiance requires atmospheric correction. This study develops a new method of retrieving BRDF on its whole domain, making it immediately suitable for further atmospheric RT modeling applications. The method is based on the integral equation relating surface-reflected radiance, BRDF, and solutions of two auxiliary atmosphere-only RT problems. The method requires kernel-based BRDF. The weights of the kernels are obtained with a quickly converging iterative procedure. RT modeling has to be done only one time before the start of iterative process.

  5. On the reflection point where light reflects to a known destination on quadratic surfaces.

    Science.gov (United States)

    Gonçalves, Nuno

    2010-01-15

    We address the problem of determining the reflection point on a specular surface where a light ray that travels from a source to a target is reflected. The specular surfaces considered are those expressed by a quadratic equation. So far, there is no closed form explicit equation for the general solution of this determination of the reflection point, and the usual approach is to use the Snell law or the Fermat principle whose equations are derived in multidimensional nonlinear minimizations. We prove in this Letter that one can impose a set of three restrictions to the reflection point that can impose a set of three restrictions that culminates in a very elegant formalism of searching the reflection point in a unidimensional curve in space. This curve is the intersection of two quadratic equations. Some applications of this framework are also discussed.

  6. Part 2: Surface water quality

    International Nuclear Information System (INIS)

    1997-01-01

    In 1996 the surface water quality measurements were performed, according to the Agreement, at 8 profiles on the Hungarian territory and at 15 profiles on the Slovak territory. Basic physical and chemical parameters (as water temperature, pH values, conductivity, suspended solids, cations and anions (nitrates, ammonium ion, nitrites, total nitrogen, phosphates, total phosphorus, oxygen and organic carbon regime parameters), metals (iron, manganese and heavy metals), biological and microbiological parameters (coliform bacteria, chlorophyll-a, saprobity index and other biological parameters) and quality of sediment were measured

  7. Retrieval and Validation of aerosol optical properties from AHI measurements: impact of surface reflectance assumption

    Science.gov (United States)

    Lim, H.; Choi, M.; Kim, J.; Go, S.; Chan, P.; Kasai, Y.

    2017-12-01

    This study attempts to retrieve the aerosol optical properties (AOPs) based on the spectral matching method, with using three visible and one near infrared channels (470, 510, 640, 860nm). This method requires the preparation of look-up table (LUT) approach based on the radiative transfer modeling. Cloud detection is one of the most important processes for guaranteed quality of AOPs. Since the AHI has several infrared channels, which are very advantageous for cloud detection, clouds can be removed by using brightness temperature difference (BTD) and spatial variability test. The Yonsei Aerosol Retrieval (YAER) algorithm is basically utilized on a dark surface, therefore a bright surface (e.g., desert, snow) should be removed first. Then we consider the characteristics of the reflectance of land and ocean surface using three visible channels. The known surface reflectivity problem in high latitude area can be solved in this algorithm by selecting appropriate channels through improving tests. On the other hand, we retrieved the AOPs by obtaining the visible surface reflectance using NIR to normalized difference vegetation index short wave infrared (NDVIswir) relationship. ESR tends to underestimate urban and cropland area, we improved the visible surface reflectance considering urban effect. In this version, ocean surface reflectance is using the new cox and munk method which considers ocean bidirectional reflectance distribution function (BRDF). Input of this method has wind speed, chlorophyll, salinity and so on. Based on validation results with the sun-photometer measurement in AErosol Robotic NETwork (AERONET), we confirm that the quality of Aerosol Optical Depth (AOD) from the YAER algorithm is comparable to the product from the Japan Aerospace Exploration Agency (JAXA) retrieval algorithm. Our future update includes a consideration of improvement land surface reflectance by hybrid approach, and non-spherical aerosols. This will improve the quality of YAER

  8. Effect of reflective surfaces on a greenhouse lettuce crop

    Energy Technology Data Exchange (ETDEWEB)

    Warman, P.R.; Mayhew, W.J.

    1979-01-01

    The Canadian greenhouse industry is an important segment of horticultural production, providing employment for thousands of people. Continuing increases in the costs of conventional fuel supplies, however, has placed the industry in some jeopardy since the cost of heating during the winter months is also escalating. In response to this problem the Brace Research Institute has developed a single roofed greenhouse designed to capture and store the sun's energy, and to increase the amount of downward solar radiation inside the greenhouse through the use of specularly-reflecting back and side walls. The research investigated the effect of a reflective surface on plant growth, development, and nutritional uptake during fall and the early months of winter. The inside walls of the greenhouse were lined with aluminized polyester to act as a reflective surface and flat black roofing felt paper to provide a non-reflecting surface. Grand Rapids Forcing lettuce was planted from seed into a peat-vermiculite bed and total solar radiation was monitored on the horizontal. Over the duration of the experiment, the reflective side of the greenhouse received more than twice as much solar radiation as the non-reflective side leading to significantly larger plant yields on the reflective side. There were no significant differences in the uptake of the plant macronutrients, N, P, K, Ca, and Mg.

  9. Internal reflection spectroscopic analysis of sulphide mineral surfaces

    International Nuclear Information System (INIS)

    Kaoma, J.

    1989-01-01

    To establish the reason for flotation of sulfide minerals in the absence of any conventional collector, internal reflection spectroscopic analysis (IRS) of their surfaces was conducted. sulfur, sulfates, thiosulfates, and hydrocarbonates have been detected on the surface of as-grand sulfide minerals. On sodium sulfide-treated surfaces, both sulfur and polysulfide have also been found to be present. From these findings, the flotation of sulfide minerals without collectors is discussed. (author). 26 refs

  10. Reflection properties of hydrogen ions at helium irradiated tungsten surfaces

    International Nuclear Information System (INIS)

    Doi, K; Tawada, Y; Kato, S; Sasao, M; Kenmotsu, T; Wada, M; Lee, H T; Ueda, Y; Tanaka, N; Kisaki, M; Nishiura, M; Matsumoto, Y; Yamaoka, H

    2016-01-01

    Nanostructured W surfaces prepared by He bombardment exhibit characteristic angular distributions of hydrogen ion reflection upon injection of 1 keV H + beam. A magnetic momentum analyzer that can move in the vacuum chamber has measured the angular dependence of the intensity and the energy of reflected ions. Broader angular distributions were observed for He-irradiated tungsten samples compared with that of the intrinsic polycrystalline W. Both intensity and energy of reflected ions decreased in the following order: the polycrystalline W, the He-bubble containing W, and the fuzz W. Classical trajectory Monte Carlo simulations based on Atomic Collision in Amorphous Target code suggests that lower atom density near the surface can make the reflection coefficients lower due to increasing number of collisions. (paper)

  11. Geometrical considerations in analyzing isotropic or anisotropic surface reflections.

    Science.gov (United States)

    Simonot, Lionel; Obein, Gael

    2007-05-10

    The bidirectional reflectance distribution function (BRDF) represents the evolution of the reflectance with the directions of incidence and observation. Today BRDF measurements are increasingly applied and have become important to the study of the appearance of surfaces. The representation and the analysis of BRDF data are discussed, and the distortions caused by the traditional representation of the BRDF in a Fourier plane are pointed out and illustrated for two theoretical cases: an isotropic surface and a brushed surface. These considerations will help characterize either the specular peak width of an isotropic rough surface or the main directions of the light scattered by an anisotropic rough surface without misinterpretations. Finally, what is believed to be a new space is suggested for the representation of the BRDF, which avoids the geometrical deformations and in numerous cases is more convenient for BRDF analysis.

  12. Reflection of slow hydrogen and helium ions from solid surfaces

    International Nuclear Information System (INIS)

    Akkerman, A.F.

    1978-01-01

    Some characteristics of the proton and helium ion flux (E < 10 keV), reflected from solid surfaces are presented. A 'condensed walk' scheme, previously used for electron transport calculations, was adapted. Results obtained either by the scheme or by a more detailed 'consequent' scheme agreed closely. The presented data permit calculations of the mean energy of reflected particles and other values for various energy and angular distributions of incident particles. (author)

  13. Angle-resolved reflection spectroscopy of high-quality PMMA opal crystal

    Science.gov (United States)

    Nemtsev, Ivan V.; Tambasov, Igor A.; Ivanenko, Alexander A.; Zyryanov, Victor Ya.

    2018-02-01

    PMMA opal crystal was prepared by a simple hybrid method, which includes sedimentation, meniscus formation and evaporation. We investigated three surfaces of this crystal by angle-resolved reflective light spectroscopy and SEM study. The angle-resolved reflective measurements were carried out in the 400-1100 nm range. We have determined the high-quality ordered surface of the crystal region. Narrow particle size distribution of the surface has been revealed. The average particle diameter obtained with SEM was nearly 361 nm. The most interesting result was that reflectivity of the surface turned out up to 98% at normal light incidence. Using a fit of dependences of the maximum reflectivity wavelength from an angle based on the Bragg-Snell law, the wavelength of maximum 0° reflectivity, the particle diameter and the fill factor have been determined. For the best surface maximum reflectivity wavelength of a 0° angle was estimated to be 869 nm. The particle diameter and fill factor were calculated as 372 nm and 0.8715, respectively. The diameter obtained by fitting is in excellent agreement with the particle diameter obtained with SEM. The reflectivity maximum is assumed to increase significantly when increasing the fill factor. We believe that using our simple approach to manufacture PMMA opal crystals will significantly increase the fabrication of high-quality photonic crystal templates and thin films.

  14. DETERMINING REFLECTANCE SPECTRA OF SURFACES AND CLOUDS ON EXOPLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, Nicolas B.; Strait, Talia E., E-mail: n-cowan@northwestern.edu [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, 2131 Tech Dr., IL 60208 (United States)

    2013-03-01

    Planned missions will spatially resolve temperate terrestrial planets from their host star. Although reflected light from such a planet encodes information about its surface, it has not been shown how to establish surface characteristics of a planet without assuming known surfaces to begin with. We present a reanalysis of disk-integrated, time-resolved, multiband photometry of Earth obtained by the Deep Impact spacecraft as part of the EPOXI Mission of Opportunity. We extract reflectance spectra of clouds, ocean, and land without a priori knowledge of the numbers or colors of these surfaces. We show that the inverse problem of extracting surface spectra from such data is a novel and extreme instance of spectral unmixing, a well-studied problem in remote sensing. Principal component analysis is used to determine an appropriate number of model surfaces with which to interpret the data. Shrink-wrapping a simplex to the color excursions of the planet yields a conservative estimate of the planet's endmember spectra. The resulting surface maps are unphysical, however, requiring negative or larger-than-unity surface coverage at certain locations. Our ''rotational unmixing'' supersedes the endmember analysis by simultaneously solving for the surface spectra and their geographical distributions on the planet, under the assumption of diffuse reflection and known viewing geometry. We use a Markov Chain Monte Carlo to determine best-fit parameters and their uncertainties. The resulting albedo spectra are similar to clouds, ocean, and land seen through a Rayleigh-scattering atmosphere. This study suggests that future direct-imaging efforts could identify and map unknown surfaces and clouds on exoplanets.

  15. Earth surface reflectance climatology from 3 years of OMI data

    NARCIS (Netherlands)

    Kleipool, Q.L.; Dobber, M.R.; Haan, de J.F.; Levelt, P.F.

    2008-01-01

    Global maps of the Earth's surface Lambertian equivalent reflectance (LER) are constructed using 3 years of Ozone Monitoring Instrument (OMI) measurements obtained between October 2004 and October 2007 at 23 wavelengths between 328 and 500 nm. The maps are constructed on a 0.5° by 0.5°

  16. Nanoimprinted reflecting gratings for long-range surface plasmon polaritons

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Haugstrup; Boltasseva, Alexandra; Johansen, Dan Mario

    2007-01-01

    We present a novel design, fabrication, and characterization of reflecting gratings for long-range surface plasmon polaritons (LR-SPPs) at telecom wavelengths. LR-SPP waveguides consisting of a thin (12 nm) gold film embedded in a thick (45 μm) layer of dielectric polymer cladding are structured...

  17. An instrument for the measurement of road surface reflection properties

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.

    2017-01-01

    Road surface reflection data in the form of standard r-tables serve as input for design calculations of road lighting installations on traffic roads. However, in several countries the use of the standard r-tables has not been verified by measurement in a long period of time, while the types of road...

  18. Copper-assisted, anti-reflection etching of silicon surfaces

    Science.gov (United States)

    Toor, Fatima; Branz, Howard

    2014-08-26

    A method (300) for etching a silicon surface (116) to reduce reflectivity. The method (300) includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (116), with a particle-to-particle spacing of 3 to 8 nanometers. The method (300) includes positioning (310) the substrate (112) with a silicon surface (116) into a vessel (122). The vessel (122) is filled (340) with a volume of an etching solution (124) so as to cover the silicon surface (116). The etching solution (124) includes an oxidant-etchant solution (146), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface (116) is etched (350) by agitating the etching solution (124) with, for example, ultrasonic agitation, and the etching may include heating (360) the etching solution (124) and directing light (365) onto the silicon surface (116). During the etching, copper nanoparticles enhance or drive the etching process.

  19. Mercury's Surface Magnetic Field Determined from Proton-Reflection Magnetometry

    Science.gov (United States)

    Winslow, Reka M.; Johnson, Catherine L.; Anderson, Brian J.; Gershman, Daniel J.; Raines, Jim M.; Lillis, Robert J.; Korth, Haje; Slavin, James A.; Solomon, Sean C.; Zurbuchen, Thomas H.; hide

    2014-01-01

    Solar wind protons observed by the MESSENGER spacecraft in orbit about Mercury exhibit signatures of precipitation loss to Mercury's surface. We apply proton-reflection magnetometry to sense Mercury's surface magnetic field intensity in the planet's northern and southern hemispheres. The results are consistent with a dipole field offset to the north and show that the technique may be used to resolve regional-scale fields at the surface. The proton loss cones indicate persistent ion precipitation to the surface in the northern magnetospheric cusp region and in the southern hemisphere at low nightside latitudes. The latter observation implies that most of the surface in Mercury's southern hemisphere is continuously bombarded by plasma, in contrast with the premise that the global magnetic field largely protects the planetary surface from the solar wind.

  20. Reflection on Cuboid Net with Mathematical Learning Quality

    Science.gov (United States)

    Sari, Atikah; Suryadi, Didi; Syaodih, Ernawulan

    2017-09-01

    This research aims to formulate an alternative to the reflection in mathematics learning activities related to the activities of the professionalism of teachers motivated by a desire to improve the quality of learning. This study is a qualitative study using the Didactical Design research. This study was conducted in one of the elementary schools. The data collection techniques are triangulation with the research subject is teacher 5th grade. The results of this study indicate that through deep reflection, teachers can design learning design in accordance with the conditions of the class. Also revealed that teachers have difficulty in choosing methods of learning and contextual learning media. Based on the implementation of activities of reflection and make the learning design based on the results of reflection can be concluded that the quality of learning in the class will develop.

  1. An instrument for the measurement of road surface reflection properties

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.

    2017-01-01

    surfaces in use have changed - for instance to road surface types with less noise from wheel passages. Because of this, a co-operation between the road administrations of the Nordic countries (abbreviated NMF) decided to construct a portable instrument to be used on selections of traffic roads within......Road surface reflection data in the form of standard r-tables serve as input for design calculations of road lighting installations on traffic roads. However, in several countries the use of the standard r-tables has not been verified by measurement in a long period of time, while the types of road...

  2. Repulsive Casimir-Polder potential by a negative reflecting surface

    Science.gov (United States)

    Yuan, Qi-Zhang

    2015-07-01

    We present a scheme to generate an all-range long repulsive Casimir-Polder potential between a perfect negative reflecting surface and a ground-state atom. The repulsive potential is stable and does not decay with time. The Casimir-Polder potential is proportional to z-2 at short atom-surface distances and to z-4 at long atom-surface distances. Because of these advantages, this potential can help in building quantum reflectors, quantum levitating devices, and waveguides for matter waves.

  3. Excitations of surface plasmon polaritons by attenuated total reflection, revisited

    International Nuclear Information System (INIS)

    Barchesi, D.; Otto, A.

    2013-01-01

    Many textbooks and review papers are devoted to plasmonics based on a selection of the numerous bibliography. But none describes the details of the first culmination of plasmonics in 1968, when surface plasmons become a field of optics. The coupling of light with the surface plasmon leads to the surface plasmon polariton (SPP). Therefore, the authors chose to associate historical insight (not avoiding a personal touch), a modern mathematical formulation of the excitation of the SPP by attenuated total reflection (ATR), considered as well understood since decades, and experimental applications since 1969, including recent developments.

  4. Seismic data enhancement with Common Reflection Surface (CRS) stack method

    Energy Technology Data Exchange (ETDEWEB)

    Baykulov, M.; Brink, H.J.; Gajewski, D.; Yoon, Mi-Kyung [Hamburg Univ. (Germany). Inst. fuer Geophysik

    2008-10-23

    We present the results of partial stacking of prestack seismic reflection data based on the kinematic wavefield attributes computed during the automatic CRS stack. The resulting CRS supergathers are more regularised and have better signal to noise ratio compared to original CMP gathers. The improved data can be used in any conventional processing tool instead of the original data, providing enhanced images of better quality. The CRS supergather method is especially suited for low fold seismic reflection data. Application of the new method to synthetic and real low fold data shows a clear improvement of seismograms as well as time and depth-migrated sections. (orig.)

  5. Optimization of plasma mirror reflectivity and optical quality using double laser pulses

    International Nuclear Information System (INIS)

    Scott, G G; Clarke, R J; Green, J S; Heathcote, R I; Neely, D; Bagnoud, V; Brabetz, C; Zielbauer, B; Powell, H W; McKenna, P; Arber, T D

    2015-01-01

    We measure a record 96 ±2.5% specularly reflected energy fraction from an interaction with a plasma mirror (PM) surface preionized by a controlled prepulse and find that the optical quality is dependent on the inter pulse time delay. Simulations show that the main pulse reflected energy is a strong function of plasma density scale length, which increases with the time delay and reaches a peak reflectivity for a scale length of 0.3 μm, which is achieved here for a pulse separation time of 3 ps. It is found that the incident laser quasi near field intensity distribution leads to nonuniformities in this plasma expansion and consequent critical surface position distribution. The PM optical quality is found to be governed by the resultant perturbations in the critical surface position, which become larger with inter pulse time delay. (paper)

  6. Spectral curves of surface reflectance in some Antarctic regions

    International Nuclear Information System (INIS)

    Lupi, A.; Tomasi, C.; Orsini, A.; Cacciari, A.; Vitale, V.; Georgiadis, T.; Casacchia, R.; Salvatori, R.; Salvi, S.

    2001-01-01

    Four surface reflectance models of solar radiation were determined by examining several sets of field measurements taken for clear-sky conditions at various sites in Antarctica. Each model consists of the mean spectral curve of surface reflectance in the 0.25-2.7 μm wavelength range and of the dependence curve of total abedo on the solar elevation angle h, within the range from 5 0 to 55 0 . The TNB (Terra Nova Bay) model refers to a rocky terrain where granites are predominant; the NIS (Nansen Ice Sheet) model to a glacier surface made uneven by sastrugi and streaked by irregular fractures; the HAP (High Altitude Plateau) model to a flat ice surface covered by fresh snow and scored by light sastrugi; and the RIS (Ross Ice Shelf) model to an area covered by the sea ice pack presenting many discontinuities in the reflectance features, due to melt water lakes, puddles, refrozen ice and snow pots. The reflectance curve obtained for the TNB model presents gradually increasing values as wavelength increases through the visible spectral range and almost constant values at infrared wavelengths, giving a total albedo value equal to 0.264 at = 30 0 , which increases by about 80% through the lower range of h and decreases by 12% through the upper range. The reflectance curves of the NIS, HAP and RIS models are all peaked at visible wavelengths and exhibit decreasing values throughout the infrared spectral range, giving values of total albedo equal to 0.464, 0.738 and 0.426 at h 30 0 , respectively. These values were estimated to increase by 8-14% as h decreases from 30 0 to 5 0 and to decrease by 2-4% only as h increases from 30 0 to 55 0

  7. Comparison of the bidirectional reflectance distribution function of various surfaces

    International Nuclear Information System (INIS)

    Fernandez, R.; Seasholtz, R.G.; Oberle, L.G.; Kadambi, J.R.

    1989-01-01

    This paper describes the development and use of a system to measure the bidirectional reflectance distribution function (BRDF) of various surfaces. The BRDF measurements are to be used in the analysis and design of optical measurement systems such as laser anemometers. An Ar-ion laser (514 nm) was the light source. Preliminary results are presented for eight samples: two glossy black paints, two flat black paints, black glass, sand-blasted Al, unworked Al, and a white paint. A BaSO4 white reflectance standard was used as the reference sample throughout the tests. 8 refs

  8. Reflectance variability of surface coatings reveals characteristic eigenvalue spectra

    Science.gov (United States)

    Medina, José M.; Díaz, José A.; Barros, Rui

    2012-10-01

    We have examined the trial-to-trial variability of the reflectance spectra of surface coatings containing effect pigments. Principal component analysis of reflectances was done at each detection angle separately. A method for classification of principal components is applied based on the eigenvalue spectra. It was found that the eigenvalue spectra follow characteristic power laws and depend on the detection angle. Three different subsets of principal components were examined to separate the relevant spectral features related to the pigments from other noise sources. Reconstruction of the reflectance spectra by taking only the first subset indicated that reflectance variability was higher at near-specular reflection, suggesting a correlation with the trial-to-trial deposition of effect pigments. Reconstruction by using the second subset indicates that variability was higher at short wavelengths. Finally, reconstruction by using only the third subset indicates that reflectance variability was not totally random as a function of the wavelength. The methods employed can be useful in the evaluation of color variability in industrial paint application processes.

  9. GLOBAL LAND COVER CLASSIFICATION USING MODIS SURFACE REFLECTANCE PROSUCTS

    Directory of Open Access Journals (Sweden)

    K. Fukue

    2016-06-01

    Full Text Available The objective of this study is to develop high accuracy land cover classification algorithm for Global scale by using multi-temporal MODIS land reflectance products. In this study, time-domain co-occurrence matrix was introduced as a classification feature which provides time-series signature of land covers. Further, the non-parametric minimum distance classifier was introduced for timedomain co-occurrence matrix, which performs multi-dimensional pattern matching for time-domain co-occurrence matrices of a classification target pixel and each classification classes. The global land cover classification experiments have been conducted by applying the proposed classification method using 46 multi-temporal(in one year SR(Surface Reflectance and NBAR(Nadir BRDF-Adjusted Reflectance products, respectively. IGBP 17 land cover categories were used in our classification experiments. As the results, SR and NBAR products showed similar classification accuracy of 99%.

  10. Unmanned aerial system nadir reflectance and MODIS nadir BRDF-adjusted surface reflectances intercompared over Greenland

    Science.gov (United States)

    Faulkner Burkhart, John; Kylling, Arve; Schaaf, Crystal B.; Wang, Zhuosen; Bogren, Wiley; Storvold, Rune; Solbø, Stian; Pedersen, Christina A.; Gerland, Sebastian

    2017-07-01

    Albedo is a fundamental parameter in earth sciences, and many analyses utilize the Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF)/albedo (MCD43) algorithms. While derivative albedo products have been evaluated over Greenland, we present a novel, direct comparison with nadir surface reflectance collected from an unmanned aerial system (UAS). The UAS was flown from Summit, Greenland, on 210 km transects coincident with the MODIS sensor overpass on board the Aqua and Terra satellites on 5 and 6 August 2010. Clear-sky acquisitions were available from the overpasses within 2 h of the UAS flights. The UAS was equipped with upward- and downward-looking spectrometers (300-920 nm) with a spectral resolution of 10 nm, allowing for direct integration into the MODIS bands 1, 3, and 4. The data provide a unique opportunity to directly compare UAS nadir reflectance with the MODIS nadir BRDF-adjusted surface reflectance (NBAR) products. The data show UAS measurements are slightly higher than the MODIS NBARs for all bands but agree within their stated uncertainties. Differences in variability are observed as expected due to different footprints of the platforms. The UAS data demonstrate potentially large sub-pixel variability of MODIS reflectance products and the potential to explore this variability using the UAS as a platform. It is also found that, even at the low elevations flown typically by a UAS, reflectance measurements may be influenced by haze if present at and/or below the flight altitude of the UAS. This impact could explain some differences between data from the two platforms and should be considered in any use of airborne platforms.

  11. Real-time defect detection on highly reflective curved surfaces

    Science.gov (United States)

    Rosati, G.; Boschetti, G.; Biondi, A.; Rossi, A.

    2009-03-01

    This paper presents an automated defect detection system for coated plastic components for the automotive industry. This research activity came up as an evolution of a previous study which employed a non-flat mirror to illuminate and inspect high reflective curved surfaces. According to this method, the rays emitted from a light source are conveyed on the surface under investigation by means of a suitably curved mirror. After the reflection on the surface, the light rays are collected by a CCD camera, in which the coating defects appear as shadows of various shapes and dimensions. In this paper we present an evolution of the above-mentioned method, introducing a simplified mirror set-up in order to reduce the costs and the complexity of the defect detection system. In fact, a set of plane mirrors is employed instead of the curved one. Moreover, the inspection of multiple bend radius parts is investigated. A prototype of the machine vision system has been developed in order to test this simplified method. This device is made up of a light projector, a set of plane mirrors for light rays reflection, a conveyor belt for handling components, a CCD camera and a desktop PC which performs image acquisition and processing. Like in the previous system, the defects are identified as shadows inside a high brightness image. At the end of the paper, first experimental results are presented.

  12. Estimates of radiance reflected towards the zenith at the surface of the sea

    Directory of Open Access Journals (Sweden)

    E. Aas

    2010-10-01

    Full Text Available Remote sensing of water colour by ship-mounted sensors represents an important tool for the validation of satellite products and the monitoring of water quality. The recorded radiance from the sea has to be corrected for the surface-reflected radiance from sun and sky in order to obtain the water-leaving radiance. Here the simple case of radiance reflected towards the zenith is studied. A set of observed sky radiance and solar irradiance data from Oslo has been used together with a Gaussian slope distribution for the sea surface in order to estimate the reflected radiance. The spectral range studied is 405–650 nm, the solar zenith angles are in the range 37°–76°, and the wind speeds are up to 10 m s−1. The analysis of the results show that the reflected radiance has to be separated into three contributions: sky radiance and sun rays reflected at the foam-free surface and irradiance reflected by whitecaps and foam. It is then demonstrated that by using four input values, namely the downward irradiance, the sky radiance from the zenith, the solar zenith angle and the wind speed, it is possible to obtain by simple expressions estimates of the reflected radiance that only differ from the former calculated values by relative errors of less than 5%. The analysis also indicates that for the spectral range studied neither the water-leaving radiance nor the surface-reflected radiance can be disregarded relative to the other one in the Case 2 waters of the Oslofjord-Skagerrak area. The results form a first step towards the study of reflected radiance in viewing angles differing from the nadir direction.

  13. Surface water quality assessment using factor analysis

    African Journals Online (AJOL)

    2006-01-16

    Jan 16, 2006 ... Surface water, groundwater quality assessment and environ- .... Urbanisation influences the water cycle through changes in flow and water ..... tion of aquatic life, CCME water quality Index 1, 0. User`s ... Water, Air Soil Pollut.

  14. Early Evaluation of the VIIRS Calibration, Cloud Mask and Surface Reflectance Earth Data Records

    Science.gov (United States)

    Vermote, Eric; Justice, Chris; Csiszar, Ivan

    2014-01-01

    Surface reflectance is one of the key products fromVIIRS and as withMODIS, is used in developing several higherorder land products. The VIIRS Surface Reflectance (SR) Intermediate Product (IP) is based on the heritageMODIS Collection 5 product (Vermote, El Saleous, & Justice, 2002). The quality and character of surface reflectance depend on the accuracy of the VIIRS Cloud Mask (VCM), the aerosol algorithms and the adequate calibration of the sensor. The focus of this paper is the early evaluation of the VIIRS SR product in the context of the maturity of the operational processing system, the Interface Data Processing System (IDPS). After a brief introduction, the paper presents the calibration performance and the role of the surface reflectance in calibration monitoring. The analysis of the performance of the cloud mask with a focus on vegetation monitoring (no snow conditions) shows typical problems over bright surfaces and high elevation sites. Also discussed is the performance of the aerosol input used in the atmospheric correction and in particular the artifacts generated by the use of the Navy Aerosol Analysis and Prediction System. Early quantitative results of the performance of the SR product over the AERONET sites showthatwith the fewadjustments recommended, the accuracy iswithin the threshold specifications. The analysis of the adequacy of the SR product (Land PEATE adjusted version) in applications of societal benefits is then presented. We conclude with a set of recommendations to ensure consistency and continuity of the JPSS mission with the MODIS Land Climate Data Record.

  15. Micro reflectance difference techniques: Optical probes for surface exploration

    Energy Technology Data Exchange (ETDEWEB)

    Lastras-Martinez, L.F.; Del Pozo-Zamudio, O.; Herrera-Jasso, R.; Ulloa-Castillo, N.A.; Balderas-Navarro, R.E.; Ortega-Gallegos, J.; Lastras-Martinez, A. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, 78000 San Luis Potosi, S.L.P. (Mexico)

    2012-06-15

    Micro reflectance difference spectroscopy ({mu}-RDS) is a promising tool for the in-situ and ex-situ characterization of semiconductors surfaces and interfaces. We discuss and compare two different approaches used to measure {mu}-RD spectra. One is based on a charge-coupled device (CCD) camera, while the other uses a laser and a XY translation stage. To show the performance of these systems, we have measured surface optical anisotropies of GaSb(001) sample on which anisotropic strains have been generated by preferential mechanical polishing along [110] and [1 anti 10] directions. The spectrometers are complementary and the selection of one of them depends on the sample to be investigated and on experimental conditions. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Mars analog minerals' spectral reflectance characteristics under Martian surface conditions

    Science.gov (United States)

    Poitras, J. T.; Cloutis, E. A.; Salvatore, M. R.; Mertzman, S. A.; Applin, D. M.; Mann, P.

    2018-05-01

    We investigated the spectral reflectance properties of minerals under a simulated Martian environment. Twenty-eight different hydrated or hydroxylated phases of carbonates, sulfates, and silica minerals were selected based on past detection on Mars through spectral remote sensing data. Samples were ground and dry sieved to <45 μm grain size and characterized by XRD before and after 133 days inside a simulated Martian surface environment (pressure 5 Torr and CO2 fed). Reflectance spectra from 0.35 to 4 μm were taken periodically through a sapphire (0.35-2.5 μm) and zinc selenide (2.5-4 μm) window over a 133-day period. Mineral stability on the Martian surface was assessed through changes in spectral characteristics. Results indicate that the hydrated carbonates studied would be stable on the surface of Mars, only losing adsorbed H2O while maintaining their diagnostic spectral features. Sulfates were less stable, often with shifts in the band position of the SO, Fe, and OH absorption features. Silicas displayed spectral shifts related to SiOH and hydration state of the mineral surface, while diagnostic bands for quartz were stable. Previous detection of carbonate minerals based on 2.3-2.5 μm and 3.4-3.9 μm features appears to be consistent with our results. Sulfate mineral detection is more questionable since there can be shifts in band position related to SO4. The loss of the 0.43 μm Fe3+ band in many of the sulfates indicate that there are fewer potential candidates for Fe3+ sulfates to permanently exist on the Martian surface based on this band. The gypsum sample changed phase to basanite during desiccation as demonstrated by both reflectance and XRD. Silica on Mars has been detected using band depth ratio at 1.91 and 1.96 μm and band minimum position of the 1.4 μm feature, and the properties are also used to determine their age. This technique continues to be useful for positive silica identifications, however, silica age appears to be less consistent

  17. Degradation of Silicon Carbide Reflective Surfaces in the LEO Environment

    Science.gov (United States)

    Mileti, Sandro; Coluzzi, Plinio; Marchetti, Mario

    2009-01-01

    Space mirrors in Low Earth Orbit (LEO) encounter a degradation problem caused by the impact of atomic oxygen (ATOX) in the space environment. This paper presents an experiment of the atomic oxygen impact degradation and UV synergic effects on ground simulation. The experiment was carried out in a dedicated ATOX simulation vacuum chamber. As target materials, a polished CVD Beta-silicon carbide (SiC) coating was investigated. The selection of silicon carbide is due to its high potential candidate as a mirror layer substrate material for its good reflectance at UV wavelengths and excellent thermal diffusivity. It has highly desirable mechanical and thermal properties and can achieve an excellent surface finish. The deposition of the coatings were on carbon-based material substrate; i.e., silicon impregnated carbon fiber composite (C/SiC). Mechanical and thermal properties of the coatings such as hardness and Coefficient of Thermal Expansion (CTE) were achieved. Several atomic oxygen impact angles were studied tilting the target samples respect to the flux direction. The various impact angles permitted to analyze the different erosion rates and typologies which the mirrors would encounter in LEO environment. The degradation was analyzed in various aspects. Macroscopic mass loss per unit area, surface roughness and morphology change were basically analyzed. The exposed surfaces of the materials were observed through a Scanning Electron Microscope (SEM). Secondly, optical diagnostic of the surfaces were performed in order to investigate their variation in optical properties as the evaluation of reflectance degradation. The presence of micro-cracks caused by shrinkage, grinding, polishing or thermal cycling and the porosity in the coatings, could have led to the undercutting phenomenon. Observation of uprising of undercutting was also conducted. Remarks are given regarding capabilities in short-term mission exposures to the LEO environment of this coating.

  18. Near-surface 3D reflections seismic survey; Sanjigen senso hanshaho jishin tansa

    Energy Technology Data Exchange (ETDEWEB)

    Nakahigashi, H; Mitsui, H; Nakano, O; Kobayashi, T [DIA Consultants Co. Ltd., Tokyo (Japan)

    1997-05-27

    Faults are being actively investigated across Japan since the Great Hanshin-Awaji Earthquake. Discussed in this report is the application of the 3D near-surface reflection seismic survey in big cities. Data from trenching and drilling is used for the geological interpretation of the surroundings of a fault, and the reflection seismic survey is used to identify the position, etc., of the fault. In this article, when the results obtained from the experimental field are examined, it is found that the conventional 2D imaging reflection survey betrays the limit of its capability when the geological structure is complicated, that the 3D reflection seismic survey, on the contrary, is capable of high-precision imaging and, when augmented by drilling, etc., becomes capable of a more detailed interpretation, and that it also contributes effectively to the improvement of local disaster prevention in big cities. Using as the model the Tachikawa fault that runs near JR Tachikawa Station, embodiment of the 3D reflection seismic survey is reviewed. For the acquisition of data excellent in quality in a 3D reflection seismic survey conducted utilizing the roads in the sector chosen for experiment in the urban area, the shock generating points and receiving points should be positioned by taking into account the parameters in the bin arranging process so that the mid-points will be regularly distributed on the surface. 3 refs., 11 figs., 1 tab.

  19. Diffuse Reflectance Spectroscopy for Surface Measurement of Liver Pathology.

    Science.gov (United States)

    Nilsson, Jan H; Reistad, Nina; Brange, Hannes; Öberg, Carl-Fredrik; Sturesson, Christian

    2017-01-01

    Liver parenchymal injuries such as steatosis, steatohepatitis, fibrosis, and sinusoidal obstruction syndrome can lead to increased morbidity and liver failure after liver resection. Diffuse reflectance spectroscopy (DRS) is an optical measuring method that is fast, convenient, and established. DRS has previously been used on the liver with an invasive technique consisting of a needle that is inserted into the parenchyma. We developed a DRS system with a hand-held probe that is applied to the liver surface. In this study, we investigated the impact of the liver capsule on DRS measurements and whether liver surface measurements are representative of the whole liver. We also wanted to confirm that we could discriminate between tumor and liver parenchyma by DRS. The instrumentation setup consisted of a light source, a fiber-optic contact probe, and two spectrometers connected to a computer. Patients scheduled for liver resection due to hepatic malignancy were included, and DRS measurements were performed on the excised liver part with and without the liver capsule and alongside a newly cut surface. To estimate the scattering parameters and tissue chromophore volume fractions, including blood, bile, and fat, the measured diffuse reflectance spectra were applied to an analytical model. In total, 960 DRS spectra from the excised liver tissue of 18 patients were analyzed. All factors analyzed regarding tumor versus liver tissue were significantly different. When measuring through the capsule, the blood volume fraction was found to be 8.4 ± 3.5%, the lipid volume fraction was 9.9 ± 4.7%, and the bile volume fraction was 8.2 ± 4.6%. No differences could be found between surface measurements and cross-sectional measurements. In measurements with/without the liver capsule, the differences in volume fraction were 1.63% (0.75-2.77), -0.54% (-2.97 to 0.32), and -0.15% (-1.06 to 1.24) for blood, lipid, and bile, respectively. This study shows that it is possible to manage DRS

  20. Viscoelasticity evaluation of rubber by surface reflection of supersonic wave.

    Science.gov (United States)

    Omata, Nobuaki; Suga, Takahiro; Furusawa, Hirokazu; Urabe, Shinichi; Kondo, Takeru; Ni, Qing-Qing

    2006-12-22

    The main characteristic of rubber is a viscoelasticity. So it is important to research the characteristic of the viscoelasticity of the high frequency band for the friction between a rubber material and the hard one with roughness, for instance, the tire and the road. As for the measurement of the viscoelasticity of rubber, DMA (dynamic mechanical analysis) is general. However, some problems are pointed out to the measurement of the high frequency band by DMA. Then, we evaluated the viscoelasticity characteristic by the supersonic wave measurement. However, attenuation of rubber is large, and when the viscoelasticity is measured by the supersonic wave therefore, it is inconvenient and limited in a past method by means of bottom reflection. In this report, we tried the viscoelasticity evaluation by the method of using complex surface reflection coefficient and we compared with the friction coefficient under wide-range friction velocity. As a result, some relationships had been found for two properties. We report the result that character of viscoelasticity of rubber was comparable to friction coefficient.

  1. IRAS surface brightness maps of reflection nebulae in the Pleiades

    Science.gov (United States)

    Castelaz, Michael W.; Werner, M. W.; Sellgren, K.

    1987-01-01

    Surface brightness maps at 12, 25, 60, and 100 microns were made of a 2.5 deg x 2.5 deg area of the reflection nebulae in the Pleiades by coadding IRAS scans of this region. Emission is seen surrounding 17 Tau, 20 Tau, 23 Tau, and 25 Tau in all four bands, coextensive with the visible reflection nebulosity, and extending as far as 30 arcminutes from the illuminating stars. The infrared energy distributions of the nebulae peak in the 100 micron band, but up to 40 percent of the total infrared power lies in the 12 and 25 micron bands. The brightness of the 12 and 25 micron emission and the absence of temperature gradients at these wavelengths are inconsistent with the predictions of equilibrium thermal emission models. The emission at these wavelengths appears to be the result of micron nonequilibrium emission from very small grains, or from molecules consisting of 10-100 carbon atoms, which have been excited by ultraviolet radiation from the illuminating stars.

  2. X-Ray Reflectivity from the Surface of a Liquid Crystal:

    DEFF Research Database (Denmark)

    Pershan, P.S.; Als-Nielsen, Jens Aage

    1984-01-01

    X-ray reflectivity from the surface of a nematic liquid crystal is interpreted as the coherent superposition of Fresnel reflection from the surface and Bragg reflection from smectic order induced by the surface. Angular dependence of the Fresnel effect yields information on surface structure....... Measurement of the intensity of diffuse critical scattering relative to the Fresnel reflection yields the absolute value of the critical part of the density-density correlation function....

  3. The normalization of surface anisotropy effects present in SEVIRI reflectances by using the MODIS BRDF method

    DEFF Research Database (Denmark)

    Proud, Simon Richard; Zhang, Qingling; Schaaf, Crystal

    2014-01-01

    A modified version of the MODerate resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF) algorithm is presented for use in the angular normalization of surface reflectance data gathered by the Spinning Enhanced Visible and InfraRed Imager (SEVIRI...... acquisition period than the comparable MODIS products while, at the same time, removing many of the angular perturbations present within the original MSG data. The NBAR data are validated against reflectance data from the MODIS instrument and in situ data gathered at a field location in Africa throughout 2008....... It is found that the MSG retrievals are stable and are of high-quality across much of the SEVIRI disk while maintaining a higher temporal resolution than the MODIS BRDF products. However, a number of circumstances are discovered whereby the BRDF model is unable to function correctly with the SEVIRI...

  4. Quantification of the optical surface reflection and surface roughness of articular cartilage using optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Saarakkala, Simo; Wang Shuzhe; Huang Yanping; Zheng Yongping [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong (China)], E-mail: simo.saarakkala@uku.fi, E-mail: ypzheng@ieee.org

    2009-11-21

    Optical coherence tomography (OCT) is a promising new technique for characterizing the structural changes of articular cartilage in osteoarthritis (OA). The calculation of quantitative parameters from the OCT signal is an important step to develop OCT as an effective diagnostic technique. In this study, two novel parameters for the quantification of optical surface reflection and surface roughness from OCT measurements are introduced: optical surface reflection coefficient (ORC), describing the amount of a ratio of the optical reflection from cartilage surface with respect to that from a reference material, and OCT roughness index (ORI) indicating the smoothness of the cartilage surface. The sensitivity of ORC and ORI to detect changes in bovine articular cartilage samples after enzymatic degradations of collagen and proteoglycans using collagenase and trypsin enzymes, respectively, was tested in vitro. A significant decrease (p < 0.001) in ORC as well as a significant increase (p < 0.001) in ORI was observed after collagenase digestion. After trypsin digestion, no significant changes in ORC or ORI were observed. To conclude, the new parameters introduced were demonstrated to be feasible and sensitive to detect typical OA-like degenerative changes in the collagen network. From the clinical point of view, the quantification of OCT measurements is of great interest since OCT probes have been already miniaturized and applied in patient studies during arthroscopy or open knee surgery in vivo. Further studies are still necessary to demonstrate the clinical capability of the introduced parameters for naturally occurring early OA changes in the cartilage.

  5. Path integration guided with a quality map for shape reconstruction in the fringe reflection technique

    Science.gov (United States)

    Jing, Xiaoli; Cheng, Haobo; Wen, Yongfu

    2018-04-01

    A new local integration algorithm called quality map path integration (QMPI) is reported for shape reconstruction in the fringe reflection technique. A quality map is proposed to evaluate the quality of gradient data locally, and functions as a guideline for the integrated path. The presented method can be employed in wavefront estimation from its slopes over the general shaped surface with slope noise equivalent to that in practical measurements. Moreover, QMPI is much better at handling the slope data with local noise, which may be caused by the irregular shapes of the surface under test. The performance of QMPI is discussed by simulations and experiment. It is shown that QMPI not only improves the accuracy of local integration, but can also be easily implemented with no iteration compared to Southwell zonal reconstruction (SZR). From an engineering point-of-view, the proposed method may also provide an efficient and stable approach for different shapes with high-precise demand.

  6. Effects of temporal distribution of specular and diffuse reflections on perceived music quality

    Science.gov (United States)

    Smitthakorn, Pattra

    The purpose of this study was to investigate the effects of the temporal distribution of diffuse and specular reflections on the perceived acoustic qualities of music performance. Sets of impulse responses were designed with different temporal distributions of early acoustic energy (specular and diffuse reflections). Then, three types of anechoic sound sources---orchestral music, trumpet, and piano---were convolved with the designed impulse responses. The results from the listening tests revealed that different room environments were needed to acoustically support different source characteristics. The results show the following: (1) specular reflections arriving within 40 msec of the direct sound improved perceived "clarity" and "intimacy"; (2) specular reflections arriving between 40-80 msec after the direct sound improved perceived "clarity" for orchestral music; (3) specular reflections arriving later than 80 msec after the direct sound are not desirable; (4) large numbers of diffuse reflections arriving within 40 and 80 msec of the direct sound improved perceived "intimacy", "texture", and "overall impression" for all sound sources, heightened perceived "clarity" for trumpet and piano, and reduced perceived "glare" for trumpet; and (5) diffuse reflections arriving between 80-160 msec of the direct sound preserved perceived "reverberance" and reduced perceived "echoes" as opposed to specular reflections arriving in the same time period. The results of this study indicate that music performance halls should be designed to include diffuse reflections from surfaces within the 80 msec time period to achieve preferred texture, intimacy, clarity and overall impression and in the 160 msec time period to reduce echoes; specular reflections arriving within the 40 msec time period should be provided to enhance perceived clarity.

  7. Surface Flux Modeling for Air Quality Applications

    Directory of Open Access Journals (Sweden)

    Limei Ran

    2011-08-01

    Full Text Available For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic compounds, can be upward into the air as well as downward to the surface and therefore should be modeled as bi-directional fluxes. Model parameterizations of dry deposition in air quality models have been represented by simple electrical resistance analogs for almost 30 years. Uncertainties in surface flux modeling in global to mesoscale models are being slowly reduced as more field measurements provide constraints on parameterizations. However, at the same time, more chemical species are being added to surface flux models as air quality models are expanded to include more complex chemistry and are being applied to a wider array of environmental issues. Since surface flux measurements of many of these chemicals are still lacking, resistances are usually parameterized using simple scaling by water or lipid solubility and reactivity. Advances in recent years have included bi-directional flux algorithms that require a shift from pre-computation of deposition velocities to fully integrated surface flux calculations within air quality models. Improved modeling of the stomatal component of chemical surface fluxes has resulted from improved evapotranspiration modeling in land surface models and closer integration between meteorology and air quality models. Satellite-derived land use characterization and vegetation products and indices are improving model representation of spatial and temporal variations in surface flux processes. This review describes the current state of chemical dry deposition modeling, recent progress in bi-directional flux modeling, synergistic model development research with field measurements, and coupling with meteorological land surface models.

  8. Variability of Surface Reflection Amplitudes of GPR Horn Antenna Depending on Distance between Antenna and Surface

    Directory of Open Access Journals (Sweden)

    Komačka Jozef

    2016-05-01

    Full Text Available The study focused on variability of surface reflections amplitudes of GPR horn antenna in relation to distance between an antenna and a surface is presented in the paper. The air-coupled antenna with the central frequency of 1 GHz was used in the investigation. Four types of surfaces (dry pavement, wet pavement, metal plate and composite layer from gypsum and wood were tested. The distance of antenna above the surfaces was changed in the range from 37.5 cm to 53.5 cm. The amplitudes of negative and positive peaks and their variability were analysed in relation to the distance of antenna above the surfaces. Moreover, the influence of changes in the peaks of negative and positive amplitudes on the total amplitudes was assessed. It was found out the amplitudes of negative peaks for all investigated surfaces were relatively consistent in the range from 40.5 cm to 48.5 cm and the moderate decline was identified in the case of amplitudes of positive peaks in the range of distances from 37.5 cm to 51.5 cm. This decline influences the tendency of total amplitudes. Based on the results of analysis it can be stated the distance of air-coupled antenna above the surface can influence the value of total amplitude and the differences depend on the type of surface.

  9. Laser surface texturing of tool steel: textured surfaces quality evaluation

    Science.gov (United States)

    Šugár, Peter; Šugárová, Jana; Frnčík, Martin

    2016-05-01

    In this experimental investigation the laser surface texturing of tool steel of type 90MnCrV8 has been conducted. The 5-axis highly dynamic laser precision machining centre Lasertec 80 Shape equipped with the nano-second pulsed ytterbium fibre laser and CNC system Siemens 840 D was used. The planar and spherical surfaces first prepared by turning have been textured. The regular array of spherical and ellipsoidal dimples with a different dimensions and different surface density has been created. Laser surface texturing has been realized under different combinations of process parameters: pulse frequency, pulse energy and laser beam scanning speed. The morphological characterization of ablated surfaces has been performed using scanning electron microscopy (SEM) technique. The results show limited possibility of ns pulse fibre laser application to generate different surface structures for tribological modification of metallic materials. These structures were obtained by varying the processing conditions between surface ablation, to surface remelting. In all cases the areas of molten material and re-cast layers were observed on the bottom and walls of the dimples. Beside the influence of laser beam parameters on the machined surface quality during laser machining of regular hemispherical and elipsoidal dimple texture on parabolic and hemispherical surfaces has been studied.

  10. The Effect of Non-Lambertian Surface Reflectance on Aerosol Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Ricchiazzi, P.; O' Hirok, W.; Gautier, C.

    2005-03-18

    Surface reflectance is an important factor in determining the strength of aerosol radiative forcing. Previous studies of radiative forcing assumed that the reflected surface radiance is isotropic and does not depend on incident illumination angle. This Lambertian reflection model is not a very good descriptor of reflectance from real land and ocean surfaces. In this study we present computational results for the seasonal average of short and long wave aerosol radiative forcing at the top of the atmosphere and at the surface. The effect of the Lambertian assumption is found through comparison with calculations using a more detailed bi-direction reflectance distribution function (BRDF).

  11. Combined analysis of surface reflection imaging and vertical seismic profiling at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Daley, T.M.; Majer, E.L.; Karageorgi, E.

    1994-08-01

    This report presents results from surface and borehole seismic profiling performed by the Lawrence Berkeley Laboratory (LBL) on Yucca Mountain. This work was performed as part of the site characterization effort for the potential high-level nuclear waste repository. Their objective was to provide seismic imaging from the near surface (200 to 300 ft. depth) to the repository horizon and below, if possible. Among the issues addressed by this seismic imaging work are location and depth of fracturing and faulting, geologic identification of reflecting horizons, and spatial continuity of reflecting horizons. The authors believe their results are generally positive, with tome specific successes. This was the first attempt at this scale using modem seismic imaging techniques to determine geologic features on Yucca Mountain. The principle purpose of this report is to present the interpretation of the seismic reflection section in a geologic context. Three surface reflection profiles were acquired and processed as part of this study. Because of environmental concerns, all three lines were on preexisting roads. Line 1 crossed the mapped surface trace of the Ghost Dance fault and it was intended to study the dip and depth extent of the fault system. Line 2 was acquired along Drill Hole wash and was intended to help the ESF north ramp design activities. Line 3 was acquired along Yucca Crest and was designed to image geologic horizons which were thought to be less faulted along the ridge. Unfortunately, line 3 proved to have poor data quality, in part because of winds, poor field conditions and limited time. Their processing and interpretation efforts were focused on lines 1 and 2 and their associated VSP studies

  12. Automatic and improved radiometric correction of Landsat imagery using reference values from MODIS surface reflectance images

    Science.gov (United States)

    Pons, X.; Pesquer, L.; Cristóbal, J.; González-Guerrero, O.

    2014-12-01

    Radiometric correction is a prerequisite for generating high-quality scientific data, making it possible to discriminate between product artefacts and real changes in Earth processes as well as accurately produce land cover maps and detect changes. This work contributes to the automatic generation of surface reflectance products for Landsat satellite series. Surface reflectances are generated by a new approach developed from a previous simplified radiometric (atmospheric + topographic) correction model. The proposed model keeps the core of the old model (incidence angles and cast-shadows through a digital elevation model [DEM], Earth-Sun distance, etc.) and adds new characteristics to enhance and automatize ground reflectance retrieval. The new model includes the following new features: (1) A fitting model based on reference values from pseudoinvariant areas that have been automatically extracted from existing reflectance products (Terra MODIS MOD09GA) that were selected also automatically by applying quality criteria that include a geostatistical pattern model. This guarantees the consistency of the internal and external series, making it unnecessary to provide extra atmospheric data for the acquisition date and time, dark objects or dense vegetation. (2) A spatial model for atmospheric optical depth that uses detailed DEM and MODTRAN simulations. (3) It is designed so that large time-series of images can be processed automatically to produce consistent Landsat surface reflectance time-series. (4) The approach can handle most images, acquired now or in the past, regardless of the processing system, with the exception of those with extremely high cloud coverage. The new methodology has been successfully applied to a series of near 300 images of the same area including MSS, TM and ETM+ imagery as well as to different formats and processing systems (LPGS and NLAPS from the USGS; CEOS from ESA) for different degrees of cloud coverage (up to 60%) and SLC

  13. The Normalization of Surface Anisotropy Effects Present in SEVIRI Reflectances by Using the MODIS BRDF Method

    Science.gov (United States)

    Proud, Simon Richard; Zhang, Qingling; Schaaf, Crystal; Fensholt, Rasmus; Rasmussen, Mads Olander; Shisanya, Chris; Mutero, Wycliffe; Mbow, Cheikh; Anyamba, Assaf; Pak, Ed; hide

    2014-01-01

    A modified version of the MODerate resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF) algorithm is presented for use in the angular normalization of surface reflectance data gathered by the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) aboard the geostationary Meteosat Second Generation (MSG) satellites. We present early and provisional daily nadir BRDFadjusted reflectance (NBAR) data in the visible and near-infrared MSG channels. These utilize the high temporal resolution of MSG to produce BRDF retrievals with a greatly reduced acquisition period than the comparable MODIS products while, at the same time, removing many of the angular perturbations present within the original MSG data. The NBAR data are validated against reflectance data from the MODIS instrument and in situ data gathered at a field location in Africa throughout 2008. It is found that the MSG retrievals are stable and are of high-quality across much of the SEVIRI disk while maintaining a higher temporal resolution than the MODIS BRDF products. However, a number of circumstances are discovered whereby the BRDF model is unable to function correctly with the SEVIRI observations-primarily because of an insufficient spread of angular data due to the fixed sensor location or localized cloud contamination.

  14. The use of UV-visible reflectance spectroscopy as an objective tool to evaluate pearl quality.

    Science.gov (United States)

    Agatonovic-Kustrin, Snezana; Morton, David W

    2012-07-01

    Assessing the quality of pearls involves the use of various tools and methods, which are mainly visual and often quite subjective. Pearls are normally classified by origin and are then graded by luster, nacre thickness, surface quality, size, color and shape. The aim of this study was to investigate the capacity of Artificial Neural Networks (ANNs) to classify and estimate the quality of 27 different pearls from their UV-Visible spectra. Due to the opaque nature of pearls, spectroscopy measurements were performed using the Diffuse Reflectance UV-Visible spectroscopy technique. The spectra were acquired at two different locations on each pearl sample in order to assess surface homogeneity. The spectral data (inputs) were smoothed to reduce the noise, fed into ANNs and correlated to the pearl's quality/grading criteria (outputs). The developed ANNs were successful in predicting pearl type, mollusk growing species, possible luster and color enhancing, donor condition/type, recipient/host color, donor color, pearl luster, pearl color, origin. The results of this study shows that the developed UV-Vis spectroscopy-ANN method could be used as a more objective method of assessing pearl quality (grading) and may become a valuable tool for the pearl grading industry.

  15. Surface 3-D reflection seismics - implementation at the Olkiluoto site

    Energy Technology Data Exchange (ETDEWEB)

    Saksa, P.; Lehtimaeki, T.; Heikkinen, E. [Poeyry Environment Oy, Vantaa (Finland)

    2007-03-15

    Posiva Oy takes care of the final disposal of spent nuclear fuel in Finland. In year 2001 Olkiluoto was selected for the site of final disposal. Construction of the underground research facility, ONKALO, is going on at the Olkiluoto site. The aim of this work was to study the possibilities for surface 3-D seismics and to review experiences for design before field work. The physical parameters and geometric properties of the site, as well as efficient survey layout and source arrangements, were considered in this work. Reflection seismics is most used geophysical investigation method in oil exploration and earth studies in sedimentary environment. Recently method has also been applied in crystalline bedrock for ore exploration and nuclear waste disposal site investigations. The advantage of the method is high accuracy combined with large depth of investigation. The principles of seismic 2-D and 3-D soundings are well known and advanced. 3-D sounding is a straightforward expansion of 2-D line based surveying. In investigation of crystalline bedrock, the high frequency wave sources and receivers, their right use in measurements and careful processing procedure (refraction static corrections in particular) are important. Using the site parameters in 2-D numerical modeling, two cases of faulted thin layer at depths of 200, 400 and 600 meters were studied. The first case was a layer with vertical dislocation (a ramp) and the other a layer having limited width of dislocated part. Central frequencies were 100, 200, 400 and 700 Hz. Results indicate that 10 - 20 m dislocation is recognizable, but for depths greater than 600 m, over 20 meters is required. Width of the dislocated part will affect the detectability of vertical displacement. At depths of 200 m and 400 m 10 - 50 m wide parts appear as point-like scatterers, wider areas have more continuity. Dislocations larger than 20 m can be seen. From depth of 600 m over 100 m wide parts are discernible, narrower are visible

  16. Surface 3-D reflection seismics - implementation at the Olkiluoto site

    International Nuclear Information System (INIS)

    Saksa, P.; Lehtimaeki, T.; Heikkinen, E.

    2007-03-01

    Posiva Oy takes care of the final disposal of spent nuclear fuel in Finland. In year 2001 Olkiluoto was selected for the site of final disposal. Construction of the underground research facility, ONKALO, is going on at the Olkiluoto site. The aim of this work was to study the possibilities for surface 3-D seismics and to review experiences for design before field work. The physical parameters and geometric properties of the site, as well as efficient survey layout and source arrangements, were considered in this work. Reflection seismics is most used geophysical investigation method in oil exploration and earth studies in sedimentary environment. Recently method has also been applied in crystalline bedrock for ore exploration and nuclear waste disposal site investigations. The advantage of the method is high accuracy combined with large depth of investigation. The principles of seismic 2-D and 3-D soundings are well known and advanced. 3-D sounding is a straightforward expansion of 2-D line based surveying. In investigation of crystalline bedrock, the high frequency wave sources and receivers, their right use in measurements and careful processing procedure (refraction static corrections in particular) are important. Using the site parameters in 2-D numerical modeling, two cases of faulted thin layer at depths of 200, 400 and 600 meters were studied. The first case was a layer with vertical dislocation (a ramp) and the other a layer having limited width of dislocated part. Central frequencies were 100, 200, 400 and 700 Hz. Results indicate that 10 - 20 m dislocation is recognizable, but for depths greater than 600 m, over 20 meters is required. Width of the dislocated part will affect the detectability of vertical displacement. At depths of 200 m and 400 m 10 - 50 m wide parts appear as point-like scatterers, wider areas have more continuity. Dislocations larger than 20 m can be seen. From depth of 600 m over 100 m wide parts are discernible, narrower are visible

  17. Reflectance of Antarctic surfaces from multispectral radiometers: The correction of atmospheric effects

    International Nuclear Information System (INIS)

    Zibordi, G.; Maracci, G.

    1993-01-01

    Monitoring reflectance of polar icecaps has relevance in climate studies. In fact, climate changes produce variations in the morphology of ice and snow covers, which are detectable as surface reflectance change. Surface reflectance can be retrieved from remotely sensed data. However, absolute values independent of atmospheric turbidity and surface altitude can only be obtained after removing masking effects of the atmosphere. An atmospheric correction model, accounting for surface and sensor altitudes above sea level, is described and validated through data detected over Antarctic surfaces with a Barnes Modular Multispectral Radiometer having bands overlapping those of the Landsat Thematic Mapper. The model is also applied in a sensitivity analysis to investigate error induced in reflectance obtained from satellite data by indeterminacy in optical parameters of atmospheric constituents. Results show that indeterminacy in the atmospheric water vapor optical thickness is the main source of nonaccuracy in the retrieval of surface reflectance from data remotely sensed over Antarctic regions

  18. Quantum reflection of fast atoms from insulator surfaces: Eikonal description

    Energy Technology Data Exchange (ETDEWEB)

    Gravielle, M S; Miraglia, J E, E-mail: msilvia@iafe.uba.a, E-mail: miraglia@iafe.uba.a [Instituto de Astronomia y Fisica del Espacio, CONICET, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Dpto. de Fisica, FCEN, Universidad de Buenos Aires (Argentina)

    2009-11-01

    Interference effects recently observed in grazing scattering of swift atoms from insulator surfaces are studied within a distorted-wave method - the surface eikonal approximation. This approach makes use of the eikonal wave function, involving axial channeled trajectories. The theory is applied to helium atoms colliding with a LiF(001) surface along low-index crystallographic directions. The roles played by the projectile polarization and the surface rumpling are investigated, finding that both effects are important for the description of the experimental projectile distributions.

  19. Enhancing quality of student teachers' practices through reflective ...

    African Journals Online (AJOL)

    This paper explores the role of journal writing in enhancing student teachers' learning during school practice. It analyses data from 22 student teachers' journals and 23 questionnaires. The study focuses on the areas that student teachers reflected on most, the nature of their reflection and the extent to which previous ...

  20. Interference effects in plasom excitation by particles reflected near a metal surface

    International Nuclear Information System (INIS)

    Denton, C.D.; Gervasoni, J.L.; Barrachina, R.O.; Arista, N.R.; Universidad Nacional de Cuyo, Mendoza

    1993-01-01

    Using the dielectric formalism and the specular reflection model, we evaluate the probability of surface and bulk plasmon excitation by particles reflected in the proximity of a metal surface. We obtain a strong oscillatory behaviour as a function of the penetration distance. (author)

  1. Liquid Atomization Induced by Pulse Laser Reflection underneath Liquid Surface

    Science.gov (United States)

    Utsunomiya, Yuji; Kajiwara, Takashi; Nishiyama, Takashi; Nagayama, Kunihito; Kubota, Shiro; Nakahara, Motonao

    2009-05-01

    We observed a novel effect of pulse laser reflection at the interface between transparent materials with different refractive indices. The electric field intensity doubles when a laser beam is completely reflected from a material with a higher refractive index to a material with a lower index. This effect appreciably reduces pulse laser ablation threshold of transparent materials. We performed experiments to observe the entire ablation process for laser incidence on the water-air interface using pulse laser shadowgraphy with high-resolution film; the minimum laser fluence for laser ablation at the water-air interface was approximately 12-16 J/cm2. We confirmed that this laser ablation occurs only when the laser beam is incident on the water-air interface from water. Many slender liquid ligaments extend like a milk crown and seem to be atomized at the tip. Their detailed structures can be resolved only by pulse laser photography using high-resolution film.

  2. A Monte Carlo reflectance model for soil surfaces with three-dimensional structure

    Science.gov (United States)

    Cooper, K. D.; Smith, J. A.

    1985-01-01

    A Monte Carlo soil reflectance model has been developed to study the effect of macroscopic surface irregularities larger than the wavelength of incident flux. The model treats incoherent multiple scattering from Lambertian facets distributed on a periodic surface. Resulting bidirectional reflectance distribution functions are non-Lambertian and compare well with experimental trends reported in the literature. Examples showing the coupling of the Monte Carlo soil model to an adding bidirectional canopy of reflectance model are also given.

  3. Influence of surface roughness on the reflective properties of snow

    International Nuclear Information System (INIS)

    Zhuravleva, Tatiana B.; Kokhanovsky, Alexander A.

    2011-01-01

    In this paper the influence of 3D effect on snow reflection function (SRF) and albedo is studied in the framework of the stochastic radiative transfer theory. In particular, the corresponding equations for the averaged intensity of reflected light are solved for the ensemble of realizations of the stochastic field κ(r), describing the distribution of 3D elements on the flat semi-infinite snow layer (SISL). The reflection from the underlying SISL is modeled using the solution of the 1D radiative transfer equation. The corresponding look-up tables were compiled beforehand and used in the simulation process. In accordance with the previous studies, it was found that the albedo of snow layer is reduced (in particular, in the infrared region), if 3D effects are taken into account. There is no such a reduction, if light absorption in snow is absent. The 3D effects may increase or decrease SRF depending on the sastrugi fraction and illumination/observation conditions.

  4. Reflectivity reduction of retro-reflector installed in LHD due to plasma surface interaction

    International Nuclear Information System (INIS)

    Yoshida, N.; Ohtawa, Y.; Ebihara, A.; Akiyama, T.; Tokitani, M.; Ashikawa, N.; Kawahata, K.

    2008-10-01

    Optical reflectivity of the retro-reflector installed in LHD as the first mirror was reduced seriously by plasma wall interaction. In order to understand the mechanism of the reflectivity reduction, optical and material properties of the mirror surfaces have been examined extensively. It was found that the deposited impurity layers caused the serious reduction of the reflectivity. Formation of iron oxide, bulges structure and He bubbles are the major factors for the reflectivity reduction in the wide wave length range. (author)

  5. Quality Assurance in Psychology Programmes across Europe: Survey and Reflections

    Science.gov (United States)

    Marques, J. Frederico

    2013-01-01

    The present article examines how different institutions that offer psychology study cycles across Europe have adopted quality principles and have taken up particular quality assurance initiatives to raise standards and enhance quality. Thirty-eight different institutions from 32 countries who were members of a European psychology network responded…

  6. ASSESSMENT OF SURFACE QUALITY FOR CHOSEN MILLING STRATEGIES WHEN PRODUCING RELIEF SURFACES

    OpenAIRE

    Jan Varga; Jozef Stahovec; Jozef Beno; Marek Vrabeľ

    2014-01-01

    The paper deals with design and modeling of the relief surfaces that are produced in milling. Modeled and real surface quality is presented for the chosen fragments of the relief surfaces. Fragmentation of the relief surfaces has been made by the surface sampling. Milling strategies are compared with regard to surface formation. Surface quality was checked with regard to applied cutting conditions.

  7. Preparation of surface conductive and highly reflective silvered polyimide films by surface modification and in situ self-metallization technique

    International Nuclear Information System (INIS)

    Wu Zhanpeng; Wu Dezhen; Qi Shengli; Zhang Teng; Jin Riguang

    2005-01-01

    Double surface conductive and reflective flexible silvered polyimide films have been prepared by alkali hydroxylation of polyimide film surface and incorporation of silver ions through subsequent ion exchange. Thermal curing of silver(I) polyamate precursor leads to re-cycloimidization of modified surface with concomitant silver reduction, yielding a reflective and conductive silver surface approaching that of native metal. The reflective and conductive surface evolves only when the cure temperature rises to 300 deg. C. The metallized films usually retain the essential mechanical properties of the parent films. Films were characterized by transmission electron microscopy (TEM), scanning electron microscopy and tapping mode atomic force microscopy (AFM). AFM demonstrates that the diameter of close-packed silver particles of the silver layers was about 50-150 nm. TEM shows that thickness of silver layer on the polyimide film surface is about 400-600 nm

  8. Retrieving background surface reflectance of Himawari-8/AHI using BRDF modeling

    Science.gov (United States)

    Choi, Sungwon; Seo, Minji; Lee, Kyeong-sang; Han, Kyung-soo

    2017-04-01

    In these days, remote sensing is more important than past. And retrieving surface reflectance in remote sensing is also important. So there are many ways to retrieve surface reflectance by my countries with polar orbit and geostationary satellite. We studied Bidirectional Reflectance Distribution Function (BRDF) which is used to retrieve surface reflectance. In BRDF equation, we calculate surface reflectance using BRD components and angular data. BRD components are to calculate 3 of scatterings, isotropic geometric and volumetric scattering. To make Background Surface Reflectance (BSR) of Himawari-8/AHI. We used 5 bands (band1, band2, band3, band4, band5) with BRDF. And we made 5 BSR for 5 channels. For validation, we compare BSR with Top of canopy (TOC) reflectance of AHI. As a result, bias are from -0.00223 to 0.008328 and Root Mean Square Error (RMSE) are from 0.045 to 0.049. We think BSR can be used to replace TOC reflectance in remote sensing to improve weakness of TOC reflectance.

  9. Generating Land Surface Reflectance for the New Generation of Geostationary Satellite Sensors with the MAIAC Algorithm

    Science.gov (United States)

    Wang, W.; Wang, Y.; Hashimoto, H.; Li, S.; Takenaka, H.; Higuchi, A.; Lyapustin, A.; Nemani, R. R.

    2017-12-01

    The latest generation of geostationary satellite sensors, including the GOES-16/ABI and the Himawari 8/AHI, provide exciting capability to monitor land surface at very high temporal resolutions (5-15 minute intervals) and with spatial and spectral characteristics that mimic the Earth Observing System flagship MODIS. However, geostationary data feature changing sun angles at constant view geometry, which is almost reciprocal to sun-synchronous observations. Such a challenge needs to be carefully addressed before one can exploit the full potential of the new sources of data. Here we take on this challenge with Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm, recently developed for accurate and globally robust applications like the MODIS Collection 6 re-processing. MAIAC first grids the top-of-atmosphere measurements to a fixed grid so that the spectral and physical signatures of each grid cell are stacked ("remembered") over time and used to dramatically improve cloud/shadow/snow detection, which is by far the dominant error source in the remote sensing. It also exploits the changing sun-view geometry of the geostationary sensor to characterize surface BRDF with augmented angular resolution for accurate aerosol retrievals and atmospheric correction. The high temporal resolutions of the geostationary data indeed make the BRDF retrieval much simpler and more robust as compared with sun-synchronous sensors such as MODIS. As a prototype test for the geostationary-data processing pipeline on NASA Earth Exchange (GEONEX), we apply MAIAC to process 18 months of data from Himawari 8/AHI over Australia. We generate a suite of test results, including the input TOA reflectance and the output cloud mask, aerosol optical depth (AOD), and the atmospherically-corrected surface reflectance for a variety of geographic locations, terrain, and land cover types. Comparison with MODIS data indicates a general agreement between the retrieved surface reflectance

  10. STACKING ON COMMON REFLECTION SURFACE WITH MULTIPARAMETER TRAVELTIME

    Directory of Open Access Journals (Sweden)

    Montes V. Luis A.

    2006-12-01

    Full Text Available Commonly seismic images are displayed in time domain because the model in depth can be known only in well logs. To produce seismic sections, pre and post stack processing approaches use time or depth velocity models whereas the common reflection method does not, instead it requires a set of parameters established for the first layer. A set of synthetic data of an anticline model, with sources and receivers placed on a flat topography, was used to observe the performance of this method. As result, a better reflector recovering compared against conventional processing sequence was observed.
    The procedure was extended to real data, using a dataset acquired on a zone characterized by mild topography and quiet environment reflectors in the Eastern Colombia planes, observing an enhanced and a better continuity of the reflectors in the CRS stacked section.

  11. Noninvasive assessment of articular cartilage surface damage using reflected polarized light microscopy

    Science.gov (United States)

    Huynh, Ruby N.; Nehmetallah, George; Raub, Christopher B.

    2017-06-01

    Articular surface damage occurs to cartilage during normal aging, osteoarthritis, and in trauma. A noninvasive assessment of cartilage microstructural alterations is useful for studies involving cartilage explants. This study evaluates polarized reflectance microscopy as a tool to assess surface damage to cartilage explants caused by mechanical scraping and enzymatic degradation. Adult bovine articular cartilage explants were scraped, incubated in collagenase, or underwent scrape and collagenase treatments. In an additional experiment, cartilage explants were subject to scrapes at graduated levels of severity. Polarized reflectance parameters were compared with India ink surface staining, features of histological sections, changes in explant wet weight and thickness, and chondrocyte viability. The polarized reflectance signal was sensitive to surface scrape damage and revealed individual scrape features consistent with India ink marks. Following surface treatments, the reflectance contrast parameter was elevated and correlated with image area fraction of India ink. After extensive scraping, polarized reflectance contrast and chondrocyte viability were lower than that from untreated explants. As part of this work, a mathematical model was developed and confirmed the trend in the reflectance signal due to changes in surface scattering and subsurface birefringence. These results demonstrate the effectiveness of polarized reflectance microscopy to sensitively assess surface microstructural alterations in articular cartilage explants.

  12. Patellar Skin Surface Temperature by Thermography Reflects Knee Osteoarthritis Severity

    OpenAIRE

    Anna E. Denoble; Norine Hall; Carl F. Pieper; Virginia B. Kraus

    2010-01-01

    Background: Digital infrared thermal imaging is a means of measuring the heat radiated from the skin surface. Our goal was to develop and assess the reproducibility of serial infrared measurements of the knee and to assess the association of knee temperature by region of interest with radiographic severity of knee Osteoarthritis (rOA). Methods: A total of 30 women (15 Cases with symptomatic knee OA and 15 age-matched Controls without knee pain or knee OA) participated in this study. Infrared ...

  13. Unmanned aerial system nadir reflectance and MODIS nadir BRDF-adjusted surface reflectances intercompared over Greenland

    Directory of Open Access Journals (Sweden)

    J. F. Burkhart

    2017-07-01

    Full Text Available Albedo is a fundamental parameter in earth sciences, and many analyses utilize the Moderate Resolution Imaging Spectroradiometer (MODIS bidirectional reflectance distribution function (BRDF/albedo (MCD43 algorithms. While derivative albedo products have been evaluated over Greenland, we present a novel, direct comparison with nadir surface reflectance collected from an unmanned aerial system (UAS. The UAS was flown from Summit, Greenland, on 210 km transects coincident with the MODIS sensor overpass on board the Aqua and Terra satellites on 5 and 6 August 2010. Clear-sky acquisitions were available from the overpasses within 2 h of the UAS flights. The UAS was equipped with upward- and downward-looking spectrometers (300–920 nm with a spectral resolution of 10 nm, allowing for direct integration into the MODIS bands 1, 3, and 4. The data provide a unique opportunity to directly compare UAS nadir reflectance with the MODIS nadir BRDF-adjusted surface reflectance (NBAR products. The data show UAS measurements are slightly higher than the MODIS NBARs for all bands but agree within their stated uncertainties. Differences in variability are observed as expected due to different footprints of the platforms. The UAS data demonstrate potentially large sub-pixel variability of MODIS reflectance products and the potential to explore this variability using the UAS as a platform. It is also found that, even at the low elevations flown typically by a UAS, reflectance measurements may be influenced by haze if present at and/or below the flight altitude of the UAS. This impact could explain some differences between data from the two platforms and should be considered in any use of airborne platforms.

  14. Surface quality in rapid prototype MMD process

    Directory of Open Access Journals (Sweden)

    Lisandro Vargas Henríquez

    2004-09-01

    Full Text Available This article summarises a Manufacturing Materials and Processes MSc thesis written for the Mechanical and Electrical Engineering Department. The paper shows the interaction of process, gap (deposition distance and extursion terminal velocity modelled process parameters for CEIF's (Centro de Equipos Interfacultades rapid prototype molten material deposit (MMD Titan SH-1 machine by analysing prototupes improved surface quality and resistence to tension and characterising material. The project applies experimental design criteria for orientating the selection of experimental process parameters. Acrylonitrile-buttadin-styrene (ABS had alredy been mechanically and physicochemically characterised (i.e the material used in the MMD process.

  15. Optical Estimation of the 3D Shape of a Solar Illuminated, Reflecting Satellite Surface

    Science.gov (United States)

    Antolin, J.; Yu, Z.; Prasad, S.

    2016-09-01

    The spatial distribution of the polarized component of the power reflected by a macroscopically smooth but microscopically roughened curved surface under highly directional illumination, as characterized by an appropriate bi-directional reflectance distribution function (BRDF), carries information about the three-dimensional (3D) shape of the surface. This information can be exploited to recover the surface shape locally under rather general conditions whenever power reflectance data for at least two different illumination or observation directions can be obtained. We present here two different parametric approaches for surface reconstruction, amounting to the recovery of the surface parameters that are either the global parameters of the family to which the surface is known a priori to belong or the coefficients of a low-order polynomial that can be employed to characterize a smoothly varying surface locally over the observed patch.

  16. Vocal performance reflects individual quality in a nonpasserine

    NARCIS (Netherlands)

    Janicke, T.; Hahn, S.M.; Ritz, M.S.; Peter, H.-U.

    2008-01-01

    Recent studies on mate-quality recognition in passerines showed that females use subtle differences in sound production to assess males. We analysed long calls of brown skuas, Catharacta antarctica lonnbergi, to test whether vocal performance could serve as an indicator of individual quality in a

  17. Qualities of Early Childhood Teachers: Reflections from Teachers and Administrators.

    Science.gov (United States)

    Weitman, Catheryn J.; Humphries, Janie H.

    Data were collected from elementary school principals and kindergarten teachers in Texas and Louisiana in an effort to identify qualities that are thought to be important for kindergarten teachers. A questionnaire listing 462 qualities of early childhood teachers was compiled from literature reviews. Subjects were asked to check a maximum of 50…

  18. Nanoscale silver-assisted wet etching of crystalline silicon for anti-reflection surface textures.

    Science.gov (United States)

    Li, Rui; Wang, Shuling; Chuwongin, Santhad; Zhou, Weidong

    2013-01-01

    We report here an electro-less metal-assisted chemical etching (MacEtch) process as light management surface-texturing technique for single crystalline Si photovoltaics. Random Silver nanostructures were formed on top of the Si surface based on the thin film evaporation and annealing process. Significant reflection reduction was obtained from the fabricated Si sample, with approximately 2% reflection over a wide spectra range (300 to 1050 nm). The work demonstrates the potential of MacEtch process for anti-reflection surface texture fabrication of large area, high efficiency, and low cost thin film solar cell.

  19. SO2 frost - UV-visible reflectivity and Io surface coverage

    Science.gov (United States)

    Nash, D. B.; Fanale, F. P.; Nelson, R. M.

    1980-01-01

    The reflectance spectrum in the range 0.24-0.85 microns of SO2 frost is measured in light of the discovery of SO2 gas in the atmosphere of Io and the possible discovery of the frost on its surface. Frost deposits up to 1.5 mm thick were grown in vacuum at 130 K and bi-directional reflectance spectra were obtained. Typical SO2 frost is found to exhibit very low reflectivity (2-5%) at 0.30 microns, rising steeply at 0.32 microns to attain a maximum reflectivity (75-80%) at 4.0 microns and uniformly high reflectivity throughout the visible and near infrared. Comparison with the full disk spectrum of Io reveals that no more than 20% of the surface can be covered with optically thick SO2 frost. Combinations of surface materials including SO2 frost which can produce the observed spectrum are indicated.

  20. Perceived Average Orientation Reflects Effective Gist of the Surface.

    Science.gov (United States)

    Cha, Oakyoon; Chong, Sang Chul

    2018-03-01

    The human ability to represent ensemble visual information, such as average orientation and size, has been suggested as the foundation of gist perception. To effectively summarize different groups of objects into the gist of a scene, observers should form ensembles separately for different groups, even when objects have similar visual features across groups. We hypothesized that the visual system utilizes perceptual groups characterized by spatial configuration and represents separate ensembles for different groups. Therefore, participants could not integrate ensembles of different perceptual groups on a task basis. We asked participants to determine the average orientation of visual elements comprising a surface with a contour situated inside. Although participants were asked to estimate the average orientation of all the elements, they ignored orientation signals embedded in the contour. This constraint may help the visual system to keep the visual features of occluding objects separate from those of the occluded objects.

  1. Evaluation of BRDF Archetypes for Representing Surface Reflectance Anisotropy Using MODIS BRDF Data

    OpenAIRE

    Zhang, Hu; Jiao, Ziti; Dong, Yadong; Li, Xiaowen

    2015-01-01

    Bidirectional reflectance distribution function (BRDF) archetypes extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF/Albedo product over the global Earth Observing System Land Validation Core Sites can be used to simplify BRDF models. The present study attempts to evaluate the representativeness of BRDF archetypes for surface reflectance anisotropy. Five-year forward-modeled MODIS multi-angular reflectance (MCD-ref) and aditional actual MODIS multi-angular observat...

  2. Surface roughness and gloss study of prints: application of specular reflection at near infrared

    International Nuclear Information System (INIS)

    Silfsten, P; Dutta, R; Pääkkönen, P; Peiponen, K-E; Tåg, C-M; Gane, P A C

    2012-01-01

    Absolute reflectance data were measured with a spectrophotometer in the visible and near infrared (NIR) spectral range. The specular reflectance data in the NIR were used for the assessment of the surface roughness of magenta, yellow, cyan and black prints on paper. In addition, surface roughness data obtained from the prints with a mechanical diamond stylus, an optical profiling system and the spectrophotometer are compared with each other. The surface roughness obtained with the aid of the spectrophotometer data suggests a smoother surface than when measured with the diamond stylus and the optical profiling system. The gloss of the prints can be obtained from the absolute specular reflectance spectra in the spectral region of visible light. It is shown that specular reflection data at a fixed wavelength in the NIR are useful also in the interpretation of gloss in the visible spectral range, but using an unconventional grazing angle of incidence. (paper)

  3. NOAA Climate Data Record (CDR) of AVHRR Surface Reflectance, Version 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains gridded daily surface reflectance and brightness temperatures derived from the Advanced Very High Resolution Radiometer (AVHRR) sensors onboard...

  4. LiDAR Relative Reflectivity Surface (2011) for the St. Thomas East End Reserve, St. Thomas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 0.3x0.3 meter resolution relative seafloor reflectivity surface for the St. Thomas East End Reserve...

  5. Accounting for surface reflectance anisotropy in satellite retrievals of tropospheric NO₂

    NARCIS (Netherlands)

    Zhou, Yipin; Brunner, D.; Spurr, R.J.D.; Boersma, K.F.; Sneep, M.; Popp, C.; Buchmann, B.

    2010-01-01

    Surface reflectance is a key parameter in satellite trace gas retrievals in the UV/visible range and in particular for the retrieval of nitrogen dioxide (NO2) vertical tropospheric columns (VTCs). Current operational retrievals rely on coarse-resolution reflectance data and do not account for the

  6. Backscattered EM-wave manipulation using low cost 1-bit reflective surface at W-band

    Science.gov (United States)

    Taher Al-Nuaimi, Mustafa K.; Hong, Wei; He, Yejun

    2018-04-01

    The design of low cost 1-bit reflective (non-absorptive) surfaces for manipulation of backscattered EM-waves and radar cross section (RCS) reduction at W-band is presented in this article. The presented surface is designed based on the reflection phase cancellation principle. The unit cell used to compose the proposed surface has an obelus (division symbol of short wire and two disks above and below) like shape printed on a grounded dielectric material. Using this unit cell, surfaces that can efficiently manipulate the backscattered RCS pattern by using the proposed obelus-shaped unit cell (as ‘0’ element) and its mirrored unit cell (as ‘1’ element) in one surface with a 180°  ±  35° reflection phase difference between their reflection phases are designed. The proposed surfaces can generate various kinds of backscattered RCS patterns, such as single, three, or four lobes or even a low-level (reduced RCS) diffused reflection pattern when those two unit cells are distributed randomly across the surface aperture. For experimental characterization purposes, a 50  ×  50 mm2 surface is fabricated and measured.

  7. Patellar Skin Surface Temperature by Thermography Reflects Knee Osteoarthritis Severity

    Directory of Open Access Journals (Sweden)

    Anna E. Denoble

    2010-01-01

    Full Text Available Background Digital infrared thermal imaging is a means of measuring the heat radiated from the skin surface. Our goal was to develop and assess the reproducibility of serial infrared measurements of the knee and to assess the association of knee temperature by region of interest with radiographic severity of knee Osteoarthritis (rOA. Methods A total of 30 women (15 Cases with symptomatic knee OA and 15 age-matched Controls without knee pain or knee OA participated in this study. Infrared imaging was performed with a Meditherm Med2000™ Pro infrared camera. The reproducibility of infrared imaging of the knee was evaluated through determination of intraclass correlation coefficients (ICCs for temperature measurements from two images performed 6 months apart in Controls whose knee status was not expected to change. The average cutaneous temperature for each of five knee regions of interest was extracted using WinTes software. Knee x-rays were scored for severity of rOA based on the global Kellgren-Lawrence grading scale. Results The knee infrared thermal imaging procedure used here demonstrated long-term reproducibility with high ICCs (0.50–0.72 for the various regions of interest in Controls. Cutaneous temperature of the patella (knee cap yielded a significant correlation with severity of knee rOA (R = 0.594, P = 0.02. Conclusion The skin temperature of the patellar region correlated with x-ray severity of knee OA. This method of infrared knee imaging is reliable and as an objective measure of a sign of inflammation, temperature, indicates an interrelationship of inflammation and structural knee rOA damage.

  8. Patellar skin surface temperature by thermography reflects knee osteoarthritis severity.

    Science.gov (United States)

    Denoble, Anna E; Hall, Norine; Pieper, Carl F; Kraus, Virginia B

    2010-10-15

    Digital infrared thermal imaging is a means of measuring the heat radiated from the skin surface. Our goal was to develop and assess the reproducibility of serial infrared measurements of the knee and to assess the association of knee temperature by region of interest with radiographic severity of knee Osteoarthritis (rOA). A total of 30 women (15 Cases with symptomatic knee OA and 15 age-matched Controls without knee pain or knee OA) participated in this study. Infrared imaging was performed with a Meditherm Med2000™ Pro infrared camera. The reproducibility of infrared imaging of the knee was evaluated through determination of intraclass correlation coefficients (ICCs) for temperature measurements from two images performed 6 months apart in Controls whose knee status was not expected to change. The average cutaneous temperature for each of five knee regions of interest was extracted using WinTes software. Knee x-rays were scored for severity of rOA based on the global Kellgren-Lawrence grading scale. The knee infrared thermal imaging procedure used here demonstrated long-term reproducibility with high ICCs (0.50-0.72 for the various regions of interest) in Controls. Cutaneous temperature of the patella (knee cap) yielded a significant correlation with severity of knee rOA (R = 0.594, P = 0.02). The skin temperature of the patellar region correlated with x-ray severity of knee OA. This method of infrared knee imaging is reliable and as an objective measure of a sign of inflammation, temperature, indicates an interrelationship of inflammation and structural knee rOA damage.

  9. Calculation of Reflectance and Transmittance of Coating With Optically Rough Surfaces

    International Nuclear Information System (INIS)

    El-Depsy, A.; Shawky, A.M.

    2011-01-01

    For ideal surfaces, components of the reflected beam are related to the components of the incident beam by Fresnel reflection equation. The surfaces encountered in engineering applications deviate from ideal as a result of roughness, oxidization and contamination; hence the Radiative properties of these real surfaces differ greatly from those predicted by electromagnetic theory. In regard to problems of radiative heat transfer; the roughness of surfaces may be divided into two categories: (1) small surface irregularities such that the incident radiation cannot undergo more than a single reflection, (2) deep cavities in which the incident radiation undergoes multi-reflection. The normally incident radiation from rough surface having small irregularities is reflected partly specularly and partly diffusely [1]. Kubelka-Munk theory (K-M) [2] describes optical characteristics (e.g. reflectance, transmittance and absorbance) by a variety of light scattering media including paints, textiles and papers, and It is widely used in various industrial applications. Moder developments in radiative transfer theory (RTT) enable the derivation of (K-M) parameters from first principles [3]. Kubelka and Munk proposed a theory based on a model of two light fluxes travelling in the forward and backward directions. Subsequently a number of authors refined the theory and compared it with experimental data [4]. Several authors attempted to relate the Kubelka- Munk coefficients to the transport coefficients [5,6

  10. Quality Assurance in Higher Education: Reflection, Criticism, and Change

    Science.gov (United States)

    Yingqiang, Zhang; Yongjian, Su

    2016-01-01

    Quality assurance in modern higher education is both an accountability-oriented ideology and a technological method. It has also evolved into a increasingly rationalist and professionalized power mechanism. Its advocacy of compliance, technological mythology, and imbalance between power and responsibility are inherent disadvantages of higher…

  11. Some reflections on the emerging notion of personal quality management

    NARCIS (Netherlands)

    Jonker, J.

    1999-01-01

    States that the concept of the “classical” organisation is undoubtedly in transition. As a result new organisational concepts emerge. Addresses the nature of quality management and assurance in “organisations under construction”. Starting with a brief overview of the characteristics of new

  12. Conversational quality is affected by and reflected in prosodic entrainment

    DEFF Research Database (Denmark)

    Michalsky, Jan; Niebuhr, Oliver; Schoormann, Heike

    2018-01-01

    Prosodic entrainment is connected to various forms of communicative success. One possibility to assess successful communication in non-task-oriented everyday conversations is through the participants’ perception of conversational quality. In this study we investigate whether a speaker’s degree of...

  13. MODIS/Aqua Near Real Time (NRT) Surface Reflectance Daily L2G Global 250m SIN Grid

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS Near Real Time (NRT) Surface Reflectance products are an estimate of the surface spectral reflectance as it would be measured at ground level in the...

  14. Reflections

    Directory of Open Access Journals (Sweden)

    Joanne Embree

    2001-01-01

    Full Text Available Ideally, editorials are written one to two months before publication in the Journal. It was my turn to write this one. I had planned to write the first draft the evening after my clinic on Tuesday, September 11. It didn't get done that night or during the next week. Somehow, the topic that I had originally chosen just didn't seem that important anymore as I, along my friends and colleagues, reflected on the changes that the events of that day were likely to have on our lives.

  15. A comparison of reflectance properties on polymer micro-structured functional surface

    DEFF Research Database (Denmark)

    Regi, Francesco; Li, Dongya; Nielsen, Jannik Boll

    In this study, a functional micro-structure surface [1] has been developed as a combination of arrays of micro ridges. The scope of the surface is to achieve specific directional optical properties: that is, under constrained lighting, maximizing the reflectance from a certain viewing direction, ...

  16. Reflectance spectroscopy of biochemical components as indicators of tea, Camellia Sinensis, quality

    NARCIS (Netherlands)

    Bian, B.M.; Skidmore, A.K.; Schlerf, M.; Fei, T.; Liu, Y.F.; Wang, T.

    2010-01-01

    The potential of reflectance spectroscopy to estimate the concentration of biochemical compounds related to tea (Camellia sinensis (L.)) quality (total tea polyphenols and free amino acids) is demonstrated. Partial least squares regression (PLSR) was performed to establish the relationship between

  17. Reflections on the State of Research: Indoor Environmental Quality

    DEFF Research Database (Denmark)

    Clausen, Geo; Bekö, Gabriel; Corsi, Richard

    2011-01-01

    that with parallel research and writing efforts culminating with internal review and revision cycles. In this paper, we present our choices for the most important research findings on indoor environmental quality from the past three decades followed by a discussion of the most important research questions in our......More than 30 years after the First International Indoor Climate Symposium, ten researchers from the USA, Slovakia, Sweden, and Denmark gathered to review the current status of indoor environmental research. We initiated our review with discussions during the 1-day meeting and followed...

  18. Reflection of illumination laser from gas metal arc weld pool surface

    International Nuclear Information System (INIS)

    Ma, Xiaoji; Zhang, YuMing

    2009-01-01

    The weld pool is the core of the welding process where complex welding phenomena originate. Skilled welders acquire their process feedback primarily from the weld pool. Observation and measurement of the three-dimensional weld pool surface thus play a fundamental role in understanding and future control of complex welding processes. To this end, a laser line is projected onto the weld pool surface in pulsed gas metal arc welding (GMAW) and an imaging plane is used to intercept its reflection from the weld pool surface. Resultant images of the reflected laser are analyzed and it is found that the weld pool surface in GMAW does specularly reflect the projected laser as in gas tungsten arc welding (GTAW). Hence, the weld pool surface in GMAW is also specular and it is in principle possible that it may be observed and measured by projecting a laser pattern and then intercepting and imaging the reflection from it. Due to high frequencies of surface fluctuations, GMAW requires a relatively short time to image the reflected laser

  19. Quality Is Key--The Impact of Community Service, Community Service Quality, and Reflection on Adolescents' Volunteering Intentions

    Science.gov (United States)

    van Goethem, Anne A. J.; van Hoof, Anne; Orobio de Castro, Bram; van Aken, Marcel A. G.

    2014-01-01

    This study examined the effect of community service program-quality on changes in adolescents' intentions to volunteer. Based on the literature, volunteering intentions were expected to increase by programs with high quality community service activities (e.g., instructive activities) and educational activities including reflection. Adolescents (N=…

  20. Remote Sensing Reflectance at 667 nm, Aqua MODIS, NPP, 0.05 degrees, Global, Science Quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — MODIS measures the remote sensing reflectance (Rrs) at 667nm. This can be used to view very high concentrations of phytoplankton in the very surface of the water.

  1. Iterative discrete ordinates solution of the equation for surface-reflected radiance

    Science.gov (United States)

    Radkevich, Alexander

    2017-11-01

    This paper presents a new method of numerical solution of the integral equation for the radiance reflected from an anisotropic surface. The equation relates the radiance at the surface level with BRDF and solutions of the standard radiative transfer problems for a slab with no reflection on its surfaces. It is also shown that the kernel of the equation satisfies the condition of the existence of a unique solution and the convergence of the successive approximations to that solution. The developed method features two basic steps: discretization on a 2D quadrature, and solving the resulting system of algebraic equations with successive over-relaxation method based on the Gauss-Seidel iterative process. Presented numerical examples show good coincidence between the surface-reflected radiance obtained with DISORT and the proposed method. Analysis of contributions of the direct and diffuse (but not yet reflected) parts of the downward radiance to the total solution is performed. Together, they represent a very good initial guess for the iterative process. This fact ensures fast convergence. The numerical evidence is given that the fastest convergence occurs with the relaxation parameter of 1 (no relaxation). An integral equation for BRDF is derived as inversion of the original equation. The potential of this new equation for BRDF retrievals is analyzed. The approach is found not viable as the BRDF equation appears to be an ill-posed problem, and it requires knowledge the surface-reflected radiance on the entire domain of both Sun and viewing zenith angles.

  2. Measurement of integrated coefficients of ultracold neutron reflection from solid surfaces

    International Nuclear Information System (INIS)

    Golikov, V.V.; Kulagin, E.N.; Nikitenko, Yu.V.

    1985-01-01

    The method of measurement of the integrated coefficients of ultracold neutrons (UCN) reflection from solid surfaces is reported. A simple formula is suggested which expresses the integrated coefficients of UCN reflection from a given sample through the measured counting rate of the detector with and without strong absorber (polyethelene). The parameters are determined describing anisotropic and inhomogeneity properties of UCN reflection from Al, Mg, Pb, Zn, Mo, stainless steel, T and V are measured. The thickness of oxide layers is determined within the 5-10A accuracy limits from the experimental coefficients of UCN reflection from metals having on their surfaces the oxides with boundary velocity larger than that for the metal. It has been determined that the density of 5000 A layer of heavy ice freezed on aluminium is 0.83 +- 0.05 from the crystal ice density

  3. Manifestation of surface phonons in far infrared reflectivity of diamond-type semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Sanchez, F.L.; Perez-Rodriguez, F. [Instituto de Fisica, Universidad Autonoma de Puebla, Apdo. Post. J-48, Puebla, Pue. 72570 (Mexico)

    2004-11-01

    The coupling of surface phonons with light at (001) surfaces of diamond-structure crystals and its manifestation in far-infrared anisotropy spectra are theoretically studied. We apply the adiabatic bond charge model to describe short-range mechanical interactions together with long-range Coulomb forces and radiation fields, and we solve the corresponding system of coupled equations for the electromagnetic field and the lattice vibrations. We calculate far-infrared normal reflectance spectra of (001) surfaces of semi-infinite diamond-type crystals. In particular, we analyse reflectance spectra for the Si(001) (2 x 1) surface, which exhibit a resonance structure associated with the excitation of surface phonon modes. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Developmental prosopagnosia and super-recognition: no special role for surface reflectance processing.

    Science.gov (United States)

    Russell, Richard; Chatterjee, Garga; Nakayama, Ken

    2012-01-01

    Face recognition by normal subjects depends in roughly equal proportions on shape and surface reflectance cues, while object recognition depends predominantly on shape cues. It is possible that developmental prosopagnosics are deficient not in their ability to recognize faces per se, but rather in their ability to use reflectance cues. Similarly, super-recognizers' exceptional ability with face recognition may be a result of superior surface reflectance perception and memory. We tested this possibility by administering tests of face perception and face recognition in which only shape or reflectance cues are available to developmental prosopagnosics, super-recognizers, and control subjects. Face recognition ability and the relative use of shape and pigmentation were unrelated in all the tests. Subjects who were better at using shape or reflectance cues were also better at using the other type of cue. These results do not support the proposal that variation in surface reflectance perception ability is the underlying cause of variation in face recognition ability. Instead, these findings support the idea that face recognition ability is related to neural circuits using representations that integrate shape and pigmentation information. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Assessment of biases in MODIS surface reflectance due to Lambertian approximation

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Robert B [ORNL; SanthanaVannan, Suresh K [ORNL

    2010-08-01

    Using MODIS data and the AERONET-based Surface Reflectance Validation Network (ASRVN), this work studies errors of MODIS atmospheric correction caused by the Lambertian approximation. On one hand, this approximation greatly simplifies the radiative transfer model, reduces the size of the look-up tables, and makes operational algorithm faster. On the other hand, uncompensated atmospheric scattering caused by Lambertian model systematically biases the results. For example, for a typical bowl-shaped bidirectional reflectance distribution function (BRDF), the derived reflectance is underestimated at high solar or view zenith angles, where BRDF is high, and is overestimated at low zenith angles where BRDF is low. The magnitude of biases grows with the amount of scattering in the atmosphere, i.e., at shorter wavelengths and at higher aerosol concentration. The slope of regression of Lambertian surface reflectance vs. ASRVN bidirectional reflectance factor (BRF) is about 0.85 in the red and 0.6 in the green bands. This error propagates into the MODIS BRDF/albedo algorithm, slightly reducing the magnitude of overall reflectance and anisotropy of BRDF. This results in a small negative bias of spectral surface albedo. An assessment for the GSFC (Greenbelt, USA) validation site shows the albedo reduction by 0.004 in the near infrared, 0.005 in the red, and 0.008 in the green MODIS bands.

  6. Comparison of cloud optical depth and cloud mask applying BRDF model-based background surface reflectance

    Science.gov (United States)

    Kim, H. W.; Yeom, J. M.; Woo, S. H.

    2017-12-01

    Over the thin cloud region, satellite can simultaneously detect the reflectance from thin clouds and land surface. Since the mixed reflectance is not the exact cloud information, the background surface reflectance should be eliminated to accurately distinguish thin cloud such as cirrus. In the previous research, Kim et al (2017) was developed the cloud masking algorithm using the Geostationary Ocean Color Imager (GOCI), which is one of significant instruments for Communication, Ocean, and Meteorology Satellite (COMS). Although GOCI has 8 spectral channels including visible and near infra-red spectral ranges, the cloud masking has quantitatively reasonable result when comparing with MODIS cloud mask (Collection 6 MYD35). Especially, we noticed that this cloud masking algorithm is more specialized in thin cloud detections through the validation with Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data. Because this cloud masking method was concentrated on eliminating background surface effects from the top-of-atmosphere (TOA) reflectance. Applying the difference between TOA reflectance and the bi-directional reflectance distribution function (BRDF) model-based background surface reflectance, cloud areas both thick cloud and thin cloud can be discriminated without infra-red channels which were mostly used for detecting clouds. Moreover, when the cloud mask result was utilized as the input data when simulating BRDF model and the optimized BRDF model-based surface reflectance was used for the optimized cloud masking, the probability of detection (POD) has higher value than POD of the original cloud mask. In this study, we examine the correlation between cloud optical depth (COD) and its cloud mask result. Cloud optical depths mostly depend on the cloud thickness, the characteristic of contents, and the size of cloud contents. COD ranges from less than 0.1 for thin clouds to over 1000 for the huge cumulus due to scattering by droplets. With

  7. Surface reflectance of Antarctic bryophytes and protection from UV and visible light

    International Nuclear Information System (INIS)

    Robinson, S.A.; Wasley, J.; Turnbull, J.

    2000-01-01

    Full text: As well as determining the amount of solar radiation available for photosynthesis, the surface reflectance and absorptance characteristics of plants are their first defence against damaging effects of solar radiation. The solar spectrum can be damaging to plants in many ways. At shorter wavelengths, UV-B (280-320 nm) radiation can cause lesions in nucleic acid and proteins. Excess levels of visible radiation (400-750) can cause photoinhibition whilst high absorbtance of longer wavelengths (>750) leads to increases in temperature that can be detrimental in some environments. The adaptation of surface reflectance properties of vascular plants to particular environments are well known in some ecosystems. For example in desert ecosystems pubescent leaf surfaces that increase reflectance are common and have been demonstrated to be important to protection from photoinhibition. The epidermal characteristics of some plants are also known to change in absorptance, due to the accumulation of specific compounds. For example flavonoids which are effective screens against UV-B radiation, increase upon exposure to UV-B radiation. In this study we surveyed the natural variability in surface reflectance in mosses growing in continental Antarctica. Antarctica is experiencing large increases in incident UV-B radiation due to reductions in concentrations of stratospheric ozone. Additionally over the summer months (November January), when moss is exposed to direct sunlight, levels of visible solar radiation are also high, increasing the likelihood of photoinhibitory damage in moss. Our aim in this study is to describe the natural variability in the surface reflectance characteristics of moss, such that we have a baseline with which to assess future changes in response to changes in global climate, and imposed experimental treatments, and also to develop hypotheses with respect to how mosses have adapted to the cold and arid antarctic environment. Variability in surface

  8. Influence of Aerosols And Surface Reflectance On NO2 Retrieval Over China From 2005 to 2015

    Science.gov (United States)

    Liu, M.; Lin, J.

    2016-12-01

    Satellite observation is a powerful way to analysis annual and seasonal variations of nitrogen dioxide (NO2). However, much retrieval of vertical column densities (VCDs) of normally do not explicitly account for aerosol optical effects and surface reflectance anisotropy that vary with space and time. In traditional retrieval, aerosols' effects are often considered as cloud. However, China has complicated aerosols type and aerosol loading. Their optical properties may be very different from the cloud. Furthermore, China has undergone big changes in land use type in recent 10 years. Traditional climatology surface reflectance data may not have representation. In order to study spatial-temporal variation of and influences of these two factors on variations and trends, we use an improved retrieval method of VCDs over China, called the POMINO, based on measurements from the Ozone Monitoring Instrument (OMI), and we compare the results of without aerosol, without surface reflectance treatments and without both to the original POMINO product from 2005 to 2015. Furthermore, we will study correspondent spatial-temporal variations of aerosols, represented by MODIS aerosol optical depth (AOD) data and CALIOP extinction data; surface reflectance, represented by MODIS bidirectional reflectance distribution function (BRDF) data.

  9. Gain-Enhanced On-Chip Antenna Utilizing Artificial Magnetic Conductor Reflecting Surface at 94 GHz

    KAUST Repository

    Nafe, Mahmoud

    2015-01-01

    In this work, the use of specially patterned reflecting surfaces for improving on- chip antenna performance is investigated. By using a periodic metallic surface on top of a grounded substrate, the structure can mimic the behavior of a perfect mag- netic conductor, hence called Artificial Magnetic Conductor (AMC) surface. Unlike conventional ground plane reflecting surfaces, AMC surfaces generally enhance the radiation and impedance characteristics of close-by antennas. Based on this property, a ring-based AMC reflecting surface has been designed in the oxide layer for on-chip antennas operating at 94 GHz. Furthermore, a folded dipole antenna with its associ- ated planar feeding structures has been optimized and integrated with the developed ring-based AMC surface. The proposed design is then fabricated at KAUST clean- room facilities. Prototype characterization showed very promising results with good correlation to simulations, with the antenna exhibiting an impedance bandwidth of 10% (90-100 GHz) and peak gain of -1.4 dBi, which is the highest gain reported for on-chip antennas at this frequency band without the use of any external o↵-chip components or post-fabrication steps.

  10. Tunable natural nano-arrays : controlling surface properties and light reflectance

    International Nuclear Information System (INIS)

    Watson, J.A.; Myhra, S.; Cribb, B.W.; Hope, G.A.; Watson, G.S.

    2005-01-01

    A sudden transition or impedance mismatch from one optical medium to another can result in unwanted reflections from the surface plane. Modification of a surface by creation of a gradual change in refractive index over a significant portion of a wavelength range will result in a reduction in reflection. Multi-layered thin film coatings based on this phenomenon are widely used on a number of different surfaces (e.g. solar cells, lenses, display screens etc.) to suppress undesired reflections and/or increase light transmittance. An alternative surface modification to the multi-layered stack coating (gradient index coating) is to produce a surface with structures having a period and heights shorter than the light wavelength. These structures act like a pseudo-gradient index coating and can be described by the effective medium theory. In this study we report on nano-structures (a natural pseudo-gradient index coating) which we have found on certain species of cicada wings demonstrating their reflective effectiveness using manipulative atomic force microscopy. (author). 2 refs., 5 figs

  11. Observation on Surface Change of Fragile Glass: Temperature - Time Dependence Studied by X-Ray Reflectivity

    International Nuclear Information System (INIS)

    Kikkawa, Hiroyuki; Kitahara, Amane; Takahashi, Isao

    2004-01-01

    The structural change of a fragile glass surface close to the glass transition temperature Tg is studied by using X-ray reflectivity. Measurements were performed on surfaces of maltitol, which is a typical polyalcohol fragile glass with Tg = 320K. Upon both heating and cooling, we find the following features which are also noticed in silicate glass surfaces: (i) On heating, the surface morphology indicates a variation at temperatures below Tg; (ii) A drastic increase in surface roughness occurs at a temperature about 333K on heating, which is 13K higher than Tg; (iii) During the cooling of the sample, formation of a low-density surface layer (3nm at 293K) is observed. Prior to the crystallization, nm - μm sized domains were grown at the surface, which might not be reported for other glasses

  12. Solar flux incident on an orbiting surface after reflection from a planet

    Science.gov (United States)

    Modest, M. F.

    1980-01-01

    Algorithms describing the solar radiation impinging on an infinitesimal surface after reflection from a gray and diffuse planet are derived. The following conditions apply: only radiation from the sunny half of the planet is taken into account; the radiation must fall on the top of the orbiting surface, and radiation must come from that part of the planet that can be seen from the orbiting body. A simple approximate formula is presented which displays excellent accuracy for all significant situations, with an error which is always less than 5% of the maximum possible reflected flux. Attention is also given to solar albedo flux on a surface directly facing the planet, the influence of solar position on albedo flux, and to solar albedo flux as a function of the surface-planet tilt angle.

  13. Effect of surface characteristics on diffuse reflection radiation at lambda=0. 40. mu. m

    Energy Technology Data Exchange (ETDEWEB)

    Takashima, T [Atmospheric Environment Service, Downsview, Ontario (Canada)

    1976-08-01

    The diffuse radiation in the upward direction at the top and at an internal level of an inhomogeneous atmosphere is computed at lambda=0.40 ..mu..m. The surface is assumed to reflect light in accordance with a hybrid mode of a diffuse and specular reflector. The objective is to estimate the effect of underlying surface characteristics in terms of the diffuse radiation field. By making use of these results, accuracy in monitoring the atmospheric aerosols would be increased for the use of remote sensing satellite techniques. Junge power law (..gamma..*=3) is adopted for the size distribution of aerosols (1963), while the data given by McClatchy et al. (1971) is used for the number density of aerosols with height distribution. It is noted from the computations that the diffuse reflection radiation is affected by the surface characteristics, even if the albedo of the surface is a fixed constant and very small.

  14. Weighted least-square approach for simultaneous measurement of multiple reflective surfaces

    Science.gov (United States)

    Tang, Shouhong; Bills, Richard E.; Freischlad, Klaus

    2007-09-01

    Phase shifting interferometry (PSI) is a highly accurate method for measuring the nanometer-scale relative surface height of a semi-reflective test surface. PSI is effectively used in conjunction with Fizeau interferometers for optical testing, hard disk inspection, and semiconductor wafer flatness. However, commonly-used PSI algorithms are unable to produce an accurate phase measurement if more than one reflective surface is present in the Fizeau interferometer test cavity. Examples of test parts that fall into this category include lithography mask blanks and their protective pellicles, and plane parallel optical beam splitters. The plane parallel surfaces of these parts generate multiple interferograms that are superimposed in the recording plane of the Fizeau interferometer. When using wavelength shifting in PSI the phase shifting speed of each interferogram is proportional to the optical path difference (OPD) between the two reflective surfaces. The proposed method is able to differentiate each underlying interferogram from each other in an optimal manner. In this paper, we present a method for simultaneously measuring the multiple test surfaces of all underlying interferograms from these superimposed interferograms through the use of a weighted least-square fitting technique. The theoretical analysis of weighted least-square technique and the measurement results will be described in this paper.

  15. Modeling the Anisotropic Reflectance of a Surface with Microstructure Engineered to Obtain Visible Contrast after Rotation

    DEFF Research Database (Denmark)

    Luongo, Andrea; Falster, Viggo; Doest, Mads Emil Brix

    2017-01-01

    in previous work. The benefit of an analytical model like the one we provide is its potential to be used in computer vision for estimating the quality of a surface sample. The quality of a sample is indicated by the resemblance of camera-based contrast measurements with contrasts predicted for an idealized...

  16. An efficient approach for computing the geometrical optics field reflected from a numerically specified surface

    Science.gov (United States)

    Mittra, R.; Rushdi, A.

    1979-01-01

    An approach for computing the geometrical optic fields reflected from a numerically specified surface is presented. The approach includes the step of deriving a specular point and begins with computing the reflected rays off the surface at the points where their coordinates, as well as the partial derivatives (or equivalently, the direction of the normal), are numerically specified. Then, a cluster of three adjacent rays are chosen to define a 'mean ray' and the divergence factor associated with this mean ray. Finally, the ampilitude, phase, and vector direction of the reflected field at a given observation point are derived by associating this point with the nearest mean ray and determining its position relative to such a ray.

  17. A geometrical optics polarimetric bidirectional reflectance distribution function for dielectric and metallic surfaces.

    Science.gov (United States)

    Hyde, M W; Schmidt, J D; Havrilla, M J

    2009-11-23

    A polarimetric bidirectional reflectance distribution function (pBRDF), based on geometrical optics, is presented. The pBRDF incorporates a visibility (shadowing/masking) function and a Lambertian (diffuse) component which distinguishes it from other geometrical optics pBRDFs in literature. It is shown that these additions keep the pBRDF bounded (and thus a more realistic physical model) as the angle of incidence or observation approaches grazing and better able to model the behavior of light scattered from rough, reflective surfaces. In this paper, the theoretical development of the pBRDF is shown and discussed. Simulation results of a rough, perfect reflecting surface obtained using an exact, electromagnetic solution and experimental Mueller matrix results of two, rough metallic samples are presented to validate the pBRDF.

  18. LiDAR Relative Reflectivity Surface (2011) for Coral Bay, St. John

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 0.3x0.3 meter resolution relative seafloor reflectivity surface for Coral Bay, St. John in the U.S....

  19. Vertical-cavity surface-emitting laser vapor sensor using swelling polymer reflection modulation

    DEFF Research Database (Denmark)

    Ansbæk, Thor; Nielsen, Claus Højgård; Dohn, Søren

    2012-01-01

    Vapor detection using a low-refractive index polymer for reflection modulation of the top mirror in a vertical-cavity surface-emitting laser (VCSEL) is demonstrated. The VCSEL sensor concept presents a simple method to detect the response of a sensor polymer in the presence of volatile organic...

  20. Classification of Clean and Dirty Pighouse Surfaces Based on Spectral Reflectance

    DEFF Research Database (Denmark)

    Blanke, Mogens; Braithwaite, Ian David; Zhang, Guo-Qiang

    2004-01-01

    of designing a vision based system to locate dirty areas and subsequently direct a cleaning robot to remove dirt. Novel results include the characterisation of the spectral reflectance of real surfaces and dirt in a pig house and the design of illumination to obtain discrimination of clean from dirty areas...

  1. LiDAR Relative Reflectivity Surface (2011) for Fish Bay, St. John

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a LiDAR (Light Detection & Ranging) 0.3x0.3 meter resolution relative seafloor reflectivity surface for Fish Bay, St. John in the U.S....

  2. Bidirectional reflectance distribution function modeling of one-dimensional rough surface in the microwave band

    International Nuclear Information System (INIS)

    Guo Li-Xin; Gou Xue-Yin; Zhang Lian-Bo

    2014-01-01

    In this study, the bidirectional reflectance distribution function (BRDF) of a one-dimensional conducting rough surface and a dielectric rough surface are calculated with different frequencies and roughness values in the microwave band by using the method of moments, and the relationship between the bistatic scattering coefficient and the BRDF of a rough surface is expressed. From the theory of the parameters of the rough surface BRDF, the parameters of the BRDF are obtained using a genetic algorithm. The BRDF of a rough surface is calculated using the obtained parameter values. Further, the fitting values and theoretical calculations of the BRDF are compared, and the optimization results are in agreement with the theoretical calculation results. Finally, a reference for BRDF modeling of a Gaussian rough surface in the microwave band is provided by the proposed method. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. Intercomparison of 30+ years of AVHRR and Landsat-5 TM Surface Reflectance using Multiple Pseudo-Invariant Calibration Sites

    Science.gov (United States)

    Santamaría-Artigas, A. E.; Franch, B.; Vermote, E.; Roger, J. C.; Justice, C. O.

    2017-12-01

    The 30+ years daily surface reflectance long term data record (LTDR) from the Advanced Very High Resolution Radiometer (AVHRR) is a valuable source of information for long-term studies of the Earth surface. This LTDR was generated by combining observations from multiple AVHRR sensors aboard different NOAA satellites starting from the early 1980s, and due to the lack of on-board calibration its quality should be evaluated. Previous studies have used observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) over pseudo-invariant calibration sites (PICS) as a calibrated reference to assess the performance of AVHRR products. However, this limits the evaluation to the period after MODIS launch. In this work, the AVHRR surface reflectance LTDR was evaluated against Landsat-5 Thematic Mapper (TM) data using observations from 4 well known pseudo-invariant calibration sites (i.e. Sonoran, Saharan, Sudan1, and Libya4) over an extended time period (1984-2011). For the intercomparison, AVHRR and TM observations of each site were extracted and averaged over a 20 km x 20 km area and aggregated to monthly mean values. In order to account for the spectral differences between sensors, Hyperion hyperspectral data from the Sonoran and Libya4 sites were convolved with sensor-specific relative spectral responses, and used to compute spectral band adjustment factors (SBAFs). Results of the intercomparison are reported in terms of the root mean square difference (RMSD) and determination coefficient (r2). In general, there is good agreement between the surface reflectance products from both sensors. The overall RMSD and r2 for all the sites and AVHRR/TM combinations were 0.03 and 0.85 for the red band, and 0.04 and 0.81 for the near-infrared band. These results show the strong performance of the AVHRR surface reflectance LTDR through all of the considered period. Thus, remarking its usefulness and value for long term Earth studies. Figure 1 shows the red (filled markers

  4. Radius of curvature measurement of spherical smooth surfaces by multiple-beam interferometry in reflection

    Science.gov (United States)

    Abdelsalam, D. G.; Shaalan, M. S.; Eloker, M. M.; Kim, Daesuk

    2010-06-01

    In this paper a method is presented to accurately measure the radius of curvature of different types of curved surfaces of different radii of curvatures of 38 000,18 000 and 8000 mm using multiple-beam interference fringes in reflection. The images captured by the digital detector were corrected by flat fielding method. The corrected images were analyzed and the form of the surfaces was obtained. A 3D profile for the three types of surfaces was obtained using Zernike polynomial fitting. Some sources of uncertainty in measurement were calculated by means of ray tracing simulations and the uncertainty budget was estimated within λ/40.

  5. Mechanisms for the reflection of light atoms from crystal surfaces at kilovolt energies

    International Nuclear Information System (INIS)

    Hou, M.; Robinson, M.T.

    1978-01-01

    The computer program MARLOWE was used to investigate the backscattering of protons from the (110) surface of a nickel crystal. Grazing incidence was considered so that anisotropic effects originated mainly from the surface region. The contribution of aligned scattering was studied by comparing the results with similar calculations for an amorphous target. Energy distributions of backscattered particles were investigated for incident energies ranging from 0.1 to 5 keV. The structure of these distributions was explained by making calculations for several target thickness. Specular reflection was found to depend on the structure of the first few atomic planes only. The (110) rows in the surface plane were responsible for focusing into surface semichannels. Focusing in these semichannels was found to be the strongest under total reflection conditions (below about 1.3 keV) while the scattering intensity from surface rows increased with increasing incident energy. The orientation of the plane of incidence was found to have large influence on the relative contributions of the reflection mechanisms involved. (orig.) [de

  6. Assessing Pearl Quality Using Reflectance UV-Vis Spectroscopy: Does the Same Donor Produce Consistent Pearl Quality?

    Directory of Open Access Journals (Sweden)

    Paul C. Southgate

    2010-09-01

    Full Text Available Two groups of commercial quality (“acceptable” pearls produced using two donors, and a group of “acceptable” pearls from other donors were analyzed using reflectance UV-Vis spectrophotometry. Three pearls with different colors produced by the same donor showed different absorption spectra. Cream and gold colored pearls showed a wide absorption from 320 to about 460 nm, while there was just slight reflectance around 400 nm by the white pearl with a pink overtone. Cream and gold pearls reached a reflectance peak at 560 to 590 nm, while the white pearl with pink overtone showed slightly wider absorption in this region. Both cream and gold pearls showed an absorption peak after the reflectance peak, at about 700 nm for the cream pearl and 750 nm for the gold pearl. Two other pearls produced by the same donor (white with cream overtone and cream with various overtones showed similar spectra, which differed in their intensity. One of these pearls had very high lustre and its spectrum showed a much higher percentage reflectance than the second pearl with inferior lustre. This result may indicate that reflectance is a useful quantitative indicator of pearl lustre. The spectra of two white pearls resulting from different donors with the same color nacre (silver showed a reflectance at 260 nm, followed by absorption at 280 nm and another reflectance peak at 340 nm. After this peak the spectra for these pearls remained flat until a slight absorption peak around 700 nm. Throughout the visible region, all white pearls used in this study showed similar reflectance spectra although there were differences in reflectance intensity. Unlike the spectral results from white pearls, the results from yellow and gold pearls varied according to color saturation of the pearl. The results of this study show that similarities between absorption and reflectance spectra of cultured pearls resulting from the same saibo donor are negligible and could not be detected

  7. Critical coupling of surface plasmons in graphene attenuated total reflection geometry

    Energy Technology Data Exchange (ETDEWEB)

    Cuevas, Mauro, E-mail: cuevas@df.uba.ar [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Facultad de Ingeniería y Tecnología Informática, Universidad de Belgrano, Villanueva 1324, C1426BMJ, Buenos Aires (Argentina); Grupo de Electromagnetismo Aplicado, Departamento de Física, FCEN, Universidad de Buenos Aires and IFIBA, Ciudad Universitaria, Pabellón I, C1428EHA, Buenos Aires (Argentina)

    2016-12-09

    We study the optical response of an attenuated total reflection (ATR) structure in Otto configuration with graphene sheet, paying especial attention to the occurrence of total absorption. Our results show that due to excitation of surface plasmons on the graphene sheet, two different conditions of total absorption may occur. At these conditions, the energy loss of the surface plasmon by radiation is equal to its energy loss by absorption into the graphene sheet. We give necessary conditions on ATR parameters for the existence of total absorption. - Highlights: • Attenuated total reflection (ATR) structure with graphene sheet. • Surface plasmons and power matched condition. • Necessary conditions on ATR parameters for the existence of total absorption.

  8. Critical coupling of surface plasmons in graphene attenuated total reflection geometry

    International Nuclear Information System (INIS)

    Cuevas, Mauro

    2016-01-01

    We study the optical response of an attenuated total reflection (ATR) structure in Otto configuration with graphene sheet, paying especial attention to the occurrence of total absorption. Our results show that due to excitation of surface plasmons on the graphene sheet, two different conditions of total absorption may occur. At these conditions, the energy loss of the surface plasmon by radiation is equal to its energy loss by absorption into the graphene sheet. We give necessary conditions on ATR parameters for the existence of total absorption. - Highlights: • Attenuated total reflection (ATR) structure with graphene sheet. • Surface plasmons and power matched condition. • Necessary conditions on ATR parameters for the existence of total absorption.

  9. Sunlight reflection off the spacecraft with a solar sail on the surface of mars

    Science.gov (United States)

    Starinova, O. L.; Rozhkov, M. A.; Gorbunova, I. V.

    2018-05-01

    Modern technologies make it possible to fulfill many projects in the field of space exploration. One such project is the colonization of Mars and providing favorable conditions for living on it. Authors propose principles of functioning of the spacecraft with a solar sail, intended to create a thermal and light spot in a predetermined area of the Martian surface. This additional illumination can maintain and support certain climatic conditions on a small area where a Mars base could be located. This paper investigate the possibility of the spacecraft continuously reflect the sunlight off the solar sail on the small area of the Mars surface. The mathematical motion model in such condition of the solar sail's orientation is considered and used for motion simulation session. Moreover, the analysis of this motion is performed. Thus, were obtained parameters of the synchronic non-Keplerian orbit and spacecraft construction. In addition, were given recommendations for further applying satellites to reflect the sunlight on a planet's surface.

  10. Lunar surface remanent magnetic fields detected by the electron reflection method

    Science.gov (United States)

    Lin, R. P.; Anderson, K. A.; Bush, R.; Mcguire, R. E.; Mccoy, J. E.

    1976-01-01

    We present maps of the lunar surface remanent magnetic fields detected by the electron reflection method. These maps provide substantial coverage of the latitude band from 30 N southward to 30 S with a resolution of about 40 km and a sensitivity of about 0.2 gamma at the lunar surface. Regions of remanent magnetization are observed ranging in size from the resolution limit of 1.25 deg to above approximately 60 deg. The largest contiguous region fills the Big Backside Basin where it is intersected by the spacecraft orbital tracks. Preliminary analyses of the maps show that the source regions of lunar limb compressions correspond to regions of strong surface magnetism, and that there does not appear to be sharply discontinuous magnetization at the edges of maria. We also analyze the electron reflection observations to obtain information on the direction and distribution of magnetization in the Van de Graaff anomaly region.

  11. Lactoperoxidase catalyzed radioiodination of cell surface immunoglobulin: incorporated radioactivity may not reflect relative cell surface Ig density

    International Nuclear Information System (INIS)

    Wilder, R.L.; Yuen, C.C.; Mage, R.G.

    1979-01-01

    Rabbit and mouse splenic lymphocytes were radioiodinated by the lactoperoxidase technique, extracted with non-ionic detergent, immunoprecipitated with high titered rabbit anti-kappa antisera, and compared by SDS-PAGE. Mouse sIg peaks were reproducibly larger in size than rabbit sIg peaks (often greater than 10 times). Neither differences in incorporation of label into the rabbit cell surface, nor differences in average sIg density explain this result. Total TCA-precipitable radioactivity was similar in each species. Estimation of the relative amounts of sIg in the mouse and rabbit showed similar average sIg densities. Differences in detergent solubility, proteolytic lability, or antisera used also do not adequately account for this difference. Thus, these data indicate that radioactivity incorporated after lactoperoxidase catalyzed cell surface radioiodination may not reflect cell surface Ig density. Conclusions about cell surface density based upon relative incorporation of radioactivity should be confirmed by other approaches

  12. Probing Ultrafast Electron Dynamics at Surfaces Using Soft X-Ray Transient Reflectivity Spectroscopy

    Science.gov (United States)

    Baker, L. Robert; Husek, Jakub; Biswas, Somnath; Cirri, Anthony

    The ability to probe electron dynamics with surface sensitivity on the ultrafast time scale is critical for understanding processes such as charge separation, injection, and surface trapping that mediate efficiency in catalytic and energy conversion materials. Toward this goal, we have developed a high harmonic generation (HHG) light source for femtosecond soft x-ray reflectivity. Using this light source we investigated the ultrafast carrier dynamics at the surface of single crystalline α-Fe2O3, polycrystalline α-Fe2O3, and the mixed metal oxide, CuFeO2. We have recently demonstrated that CuFeO2 in particular is a selective catalyst for photo-electrochemical CO2 reduction to acetate; however, the role of electronic structure and charge carrier dynamics in mediating catalytic selectivity has not been well understood. Soft x-ray reflectivity measurements probe the M2,3, edges of the 3d transition metals, which provide oxidation and spin state resolution with element specificity. In addition to chemical state specificity, these measurements are also surface sensitive, and by independently simulating the contributions of the real and imaginary components of the complex refractive index, we can differentiate between surface and sub-surface contributions to the excited state spectrum. Accordingly, this work demonstrates the ability to probe ultrafast carrier dynamics in catalytic materials with element and chemical state specificity and with surface sensitivity.

  13. Evaluation of BRDF Archetypes for Representing Surface Reflectance Anisotropy Using MODIS BRDF Data

    Directory of Open Access Journals (Sweden)

    Hu Zhang

    2015-06-01

    Full Text Available Bidirectional reflectance distribution function (BRDF archetypes extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS BRDF/Albedo product over the global Earth Observing System Land Validation Core Sites can be used to simplify BRDF models. The present study attempts to evaluate the representativeness of BRDF archetypes for surface reflectance anisotropy. Five-year forward-modeled MODIS multi-angular reflectance (MCD-ref and aditional actual MODIS multi-angular observations (MCD-obs in four growing periods in 2008 over three tiles were taken as validation data. First, BRDF archetypes in the principal plane were qualitatively compared with the time-series MODIS BRDF product of randomly sampled pixels. Secondly, BRDF archetypes were used to fit MCD-ref, and the average root-mean-squared errors (RMSEs over each tile were examined for these five years. Finally, both BRDF archetypes and the MODIS BRDF were used to fit MCD-obs, and the histograms of the fit-RMSEs were compared. The consistency of the directional reflectance between the BRDF archetypes and MODIS BRDFs in nadir-view, hotspot and entire viewing hemisphere at 30° and 50° solar geometries were also examined. The results confirm that BRDF archetypes are representative of surface reflectance anisotropy for available snow-free MODIS data.

  14. Ray splitting in the reflection and refraction of surface acoustic waves in anisotropic solids.

    Science.gov (United States)

    Every, A G; Maznev, A A

    2010-05-01

    This paper examines the conditions for, and provides examples of, ray splitting in the reflection and refraction of surface acoustic waves (SAW) in elastically anisotropic solids at straight obstacles such as edges, surface breaking cracks, and interfaces between different solids. The concern here is not with the partial scattering of an incident SAW's energy into bulk waves, but with the occurrence of more than one SAW ray in the reflected and/or transmitted wave fields, by analogy with birefringence in optics and mode conversion of bulk elastic waves at interfaces. SAW ray splitting is dependent on the SAW slowness curve possessing concave regions, which within the constraint of wave vector conservation parallel to the obstacle allows multiple outgoing SAW modes for certain directions of incidence and orientation of obstacle. The existence of pseudo-SAW for a given surface provides a further channel for ray splitting. This paper discusses some typical material configurations for which SAW ray splitting occurs. An example is provided of mode conversion entailing backward reflection or negative refraction. Experimental demonstration of ray splitting in the reflection of a laser generated SAW in GaAs(111) is provided. The calculation of SAW mode conversion amplitudes lies outside the scope of this paper.

  15. Improving Image Matching by Reducing Surface Reflections Using Polarising Filter Techniques

    Science.gov (United States)

    Conen, N.; Hastedt, H.; Kahmen, O.; Luhmann, T.

    2018-05-01

    In dense stereo matching applications surface reflections may lead to incorrect measurements and blunders in the resulting point cloud. To overcome the problem of disturbing reflexions polarising filters can be mounted on the camera lens and light source. Reflections in the images can be suppressed by crossing the polarising direction of the filters leading to homogeneous illuminated images and better matching results. However, the filter may influence the camera's orientation parameters as well as the measuring accuracy. To quantify these effects, a calibration and an accuracy analysis is conducted within a spatial test arrangement according to the German guideline VDI/VDE 2634.1 (2002) using a DSLR with and without polarising filter. In a second test, the interior orientation is analysed in more detail. The results do not show significant changes of the measuring accuracy in object space and only very small changes of the interior orientation (Δc ≤ 4 μm) with the polarising filter in use. Since in medical applications many tiny reflections are present and impede robust surface measurements, a prototypic trinocular endoscope is equipped with polarising technique. The interior and relative orientation is determined and analysed. The advantage of the polarising technique for medical image matching is shown in an experiment with a moistened pig kidney. The accuracy and completeness of the resulting point cloud can be improved clearly when using polarising filters. Furthermore, an accuracy analysis using a laser triangulation system is performed and the special reflection properties of metallic surfaces are presented.

  16. Modeling and analysis of surface roughness effects on sputtering, reflection, and sputtered particle transport

    International Nuclear Information System (INIS)

    Brooks, J.N.; Ruzic, D.N.

    1990-01-01

    The microstructure of the redeposited surface in tokamaks may affect sputtering and reflection properties and subsequent particle transport. This subject has been studied numerically using coupled models/codes for near-surface plasma particle kinetic transport (WBC code) and rough surface sputtering (fractal-TRIM). The coupled codes provide an overall Monte Carlo calculation of the sputtering cascade resulting from an initial flux of hydrogen ions. Beryllium, carbon, and tungsten surfaces are analyzed for typical high recycling, oblique magnetic field, divertor conditions. Significant variations in computed sputtering rates are found with surface roughness. Beryllium exhibits high D-T and self-sputtering coefficients for the plasma regime studied (T e = 30-75 eV). Carbon and tungsten sputtering is significantly lower. 9 refs., 6 figs., 1 tab

  17. A method for the characterization of the reflectance of anisotropic functional surfaces

    DEFF Research Database (Denmark)

    Regi, Francesco; Nielsen, J B; Li, Dongya

    2018-01-01

    The functional properties of micro-structured surfaces have gained increasing interest thanks to many applications such as wetting, adhesion, thermal and/or electrical conductivity. In this study, directional optical properties, i.e. contrast between two regions of a surface, were achieved...... reflectance of the surface for a range of design-specific view-illumination configurations was determined using a method that involves a Hirox RH-2000 digital microscope, used as a gonioreflectometer. This method allows the empirical determination of the optimum surface microstructure for maximizing contrast...... between two horizontally orthogonal views. The results show that even if the uncertainty related to the instrumentation is up to 20% in some cases, this procedure is suitable for the characterization of the surface of both metal and plastic counterpart....

  18. [A Method to Reconstruct Surface Reflectance Spectrum from Multispectral Image Based on Canopy Radiation Transfer Model].

    Science.gov (United States)

    Zhao, Yong-guang; Ma, Ling-ling; Li, Chuan-rong; Zhu, Xiao-hua; Tang, Ling-li

    2015-07-01

    Due to the lack of enough spectral bands for multi-spectral sensor, it is difficult to reconstruct surface retlectance spectrum from finite spectral information acquired by multi-spectral instrument. Here, taking into full account of the heterogeneity of pixel from remote sensing image, a method is proposed to simulate hyperspectral data from multispectral data based on canopy radiation transfer model. This method first assumes the mixed pixels contain two types of land cover, i.e., vegetation and soil. The sensitive parameters of Soil-Leaf-Canopy (SLC) model and a soil ratio factor were retrieved from multi-spectral data based on Look-Up Table (LUT) technology. Then, by combined with a soil ratio factor, all the parameters were input into the SLC model to simulate the surface reflectance spectrum from 400 to 2 400 nm. Taking Landsat Enhanced Thematic Mapper Plus (ETM+) image as reference image, the surface reflectance spectrum was simulated. The simulated reflectance spectrum revealed different feature information of different surface types. To test the performance of this method, the simulated reflectance spectrum was convolved with the Landsat ETM + spectral response curves and Moderate Resolution Imaging Spectrometer (MODIS) spectral response curves to obtain the simulated Landsat ETM+ and MODIS image. Finally, the simulated Landsat ETM+ and MODIS images were compared with the observed Landsat ETM+ and MODIS images. The results generally showed high correction coefficients (Landsat: 0.90-0.99, MODIS: 0.74-0.85) between most simulated bands and observed bands and indicated that the simulated reflectance spectrum was well simulated and reliable.

  19. Bi-directional Reflectance of Icy Surface Analogs: A Dual Approach

    Science.gov (United States)

    Quinones, Juan Manuel; Vides, Christina; Nelson, Robert M.; Boryta, Mark; Mannat, Ken s.

    2018-01-01

    Bi-directional reflectance measurements of analogs for planetary regolith have provided insight into the surface properties of planetary satellites and small bodies. Because Aluminum Oxide (Al2O3) and water ice share a similar hexagonal crystalline structure, the former has been used in laboratory experiments to simulate the regolith of both icy and dusty planetary bodies. By measuring various sizes of well sorted size fractions of Al2O3, the reflectance phase curve and porosity of a planetary regolith can be determined. We have designed an experiment to test the laboratory measurements produced by Nelson et al. (2000). Additionally, we made reflectance measurements for other alkali-halide compounds that could be used for applications beyond astronomy and planetary science.In order to provide an independent check on the Nelson et al. data, we designed an instrument with a different configuration. While both instruments take bidirectional reflectance measurements, our instrument, the Rigid Photometric Goniometer (RPG), is fixed at a phase angle of 5° and detects the scattered light with a photomultiplier tube (PMT). The PMT current is then measured with an electrometer. Following the example of Nelson et al., we measured the bidirectional reflectance of Al2O3 particulate size fractions between 0.1sizes from 20size that provided optimal, or maximum, reflectance for each compound. Our conclusions bring confirmation and clarity to photometric sciences.

  20. Characterizing Land Surface Anisotropic Reflectance over Rugged Terrain: A Review of Concepts and Recent Developments

    Directory of Open Access Journals (Sweden)

    Jianguang Wen

    2018-02-01

    Full Text Available Rugged terrain, including mountains, hills, and some high lands are typical land surfaces around the world. As a physical parameter for characterizing the anisotropic reflectance of the land surface, the importance of the bidirectional reflectance distribution function (BRDF has been gradually recognized in the remote sensing community, and great efforts have been dedicated to build BRDF models over various terrain types. However, on rugged terrain, the topography intensely affects the shape and magnitude of the BRDF and creates challenges in modeling the BRDF. In this paper, after a brief introduction of the theoretical background of the BRDF over rugged terrain, the status of estimating land surface BRDF properties over rugged terrain is comprehensively reviewed from a historical perspective and summarized in two categories: BRDFs describing solo slopes and those describing composite slopes. The discussion focuses on land surface reflectance retrieval over mountainous areas, the difference in solo slope and composite slope BRDF models, and suggested future research to improve the accuracy of BRDFs derived with remote sensing satellites.

  1. The effect of surface texture on total reflection of neutrons and X-rays from modified interfaces

    DEFF Research Database (Denmark)

    Goldar, A.; Roser, S.J.; Hughes, A.

    2002-01-01

    X-ray and neutron scattering from macroscopically rough surfaces and interfaces is considered and a new method of analysis based on the variation of the shape of the total reflection edge in the reflectivity profile is proposed. It was shown that in the limit that the correlation length and the h......X-ray and neutron scattering from macroscopically rough surfaces and interfaces is considered and a new method of analysis based on the variation of the shape of the total reflection edge in the reflectivity profile is proposed. It was shown that in the limit that the correlation length...... and the height of the surface roughness are larger than the wavelength (at least 100 times bigger) of the incoming beam, the total reflection edge in the reflection profile becomes rounded. This technique allows direct analysis of the variation of the reflectivity pro le in terms of the structure of the surface...

  2. Retrieval of the Land Surface Reflectance for Landsat-8 and Sentinel-2 and its validation.

    Science.gov (United States)

    Roger, J. C.; Vermote, E.; Skakun, S.; Franch, B.; Holben, B. N.; Justice, C. O.

    2017-12-01

    The land surface reflectance is a fundamental climate data record at the basis of the derivation of other climate data records (Albedo, LAI/Fpar, Vegetation indices) and a key parameter in the understanding of the land-surface-climate processes. For 25 years, Vermote and al. develop atmospheric corrections methods to define a land surface reflectance product for various satellites (AVHRR, MODIS, VIIRS…). This presentation highlights the algorithms developed both for Landsant-8 and Sentinel-2. We also emphasize the validation of the "Land surface reflectance" satellite products, which is a very important step to be done. For that purpose, we compared the surface reflectance products to a reference determined by using the accurate radiative transfer code 6S and very detailed measurements of the atmosphere obtained over the AERONET network (which allows to test for a large range of aerosol characteristics); formers being important inputs for atmospheric corrections. However, the application of this method necessitates the definition of a very detailed protocol for the use of AERONET data especially as far as size distribution and absorption are concerned, so that alternative validation methods or protocols could be compared. We describe here the protocol we have been working on based on our experience with the AERONET data and its application to Landsat-8 and Sentinel-2). We also derive a detailed error budget in relation to this approach. For a mean loaded atmosphere, t550 less than 0.25, the maximum uncertainty is 0.0025 corresponding to a relative uncertainty (in the RED channels): U 0.10, and 1% rsurf > 0.04.

  3. Does peer coaching with video feedback improve the quality of teachers' reflections on own professional behaviour?

    NARCIS (Netherlands)

    J. van den Akker; dr Rita Schildwacht; Dr. S. Bolhuis

    2008-01-01

    Meetings with other professionals are considered crucial for enhancing the quality of teachers' reflections. However, little is yet known about how any beneficial effects of such meetings are brought about. This study explores the peer coach's roles and their influences on the learning processes of

  4. Spectral reflectance is a reliable water-quality estimator for small, highly turbid wetlands

    Czech Academy of Sciences Publication Activity Database

    Vinciková, H.; Hanuš, Jan; Pechar, L.

    2015-01-01

    Roč. 23, č. 5 (2015), s. 933-946 ISSN 0923-4861 R&D Projects: GA MŠk(CZ) LM2010007; GA MŠk 2B06068 Institutional support: RVO:67179843 Keywords : remote sensing * water quality * hyperspectral reflectance * turbid inland waters * chlorophyll * TSS Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.407, year: 2015

  5. Light reflection from a rough liquid surface including wind-wave effects in a scattering atmosphere

    International Nuclear Information System (INIS)

    Salinas, Santo V.; Liew, S.C.

    2007-01-01

    Visible and near-IR images of the ocean surface, taken from remote satellites, often contain important information of near-surface or sub-surface processes, which occur on, or over the ocean. Remote measurements of near surface winds, sea surface temperature and salinity, ocean color and underwater bathymetry, all, one way or another, depend on how well we understand sea surface roughness. However, in order to extract useful information from our remote measurements, we need to construct accurate models of the transfer of solar radiation inside the atmosphere as well as, its reflection from the sea surface. To approach this problem, we numerically solve the radiative transfer equation (RTE) by implementing a model for the atmosphere-ocean system. A one-dimensional atmospheric radiation model is solved via the widely known doubling and adding method and the ocean body is treated as a boundary condition to the problem. The ocean surface is modeled as a rough liquid surface which includes wind interaction and wave states, such as wave age. The model can have possible applications to the retrieval of wind and wave states, such as wave age, near a Sun glint region

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

    International Nuclear Information System (INIS)

    Achtelik, J.; Sievers, W.; Lindner, J.K.N.

    2013-01-01

    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

  7. 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.

  8. Self-consistent approach to x-ray reflection from rough surfaces

    International Nuclear Information System (INIS)

    Feranchuk, I. D.; Feranchuk, S. I.; Ulyanenkov, A. P.

    2007-01-01

    A self-consistent analytical approach for specular x-ray reflection from interfaces with transition layers [I. D. Feranchuk et al., Phys. Rev. B 67, 235417 (2003)] based on the distorted-wave Born approximation (DWBA) is used for the description of coherent and incoherent x-ray scattering from rough surfaces and interfaces. This approach takes into account the transformation of the modeling transition layer profile at the interface, which is caused by roughness correlations. The reflection coefficients for each DWBA order are directly calculated without phenomenological assumptions on their exponential decay at large scattering angles. Various regions of scattering angles are discussed, which show qualitatively different dependence of the reflection coefficient on the scattering angle. The experimental data are analyzed using the method developed

  9. Antarctic Surface Reflectivity Measurements from the ANITA-3 and HiCal-1 Experiments

    Science.gov (United States)

    Gorham, P. W.; Allison, P.; Banerjee, O.; Beatty, J. J.; Belov, K.; Besson, D. Z.; Binns, W. R.; Bugaev, V.; Cao, P.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Dailey, B.; Dasgupta, P.; Deaconu, C.; Cremonesi, L.; Dowkontt, P. F.; Fox, B. D.; Gordon, J.; Hill, B.; Hupe, R.; Israel, M. H.; Jain, P.; Kowalski, J.; Lam, J.; Learned, J. G.; Liewer, K. M.; Liu, T. C.; Matsuno, S.; Miki, C.; Mottram, M.; Mulrey, K.; Nam, J.; Nichol, R. J.; Novikov, A.; Oberla, E.; Prohira, S.; Rauch, B. F.; Romero-Wolf, A.; Rotter, B.; Ratzlaff, K.; Russell, J.; Saltzberg, D.; Seckel, D.; Schoorlemmer, H.; Stafford, S.; Stockham, J.; Stockham, M.; Strutt, B.; Tatem, K.; Varner, G. S.; Vieregg, A. G.; Wissel, S. A.; Wu, F.; Young, R.

    The primary science goal of the NASA-sponsored ANITA project is measurement of ultra-high energy neutrinos and cosmic rays, observed via radio-frequency signals resulting from a neutrino or cosmic ray interaction with terrestrial matter (e.g. atmospheric or ice molecules). Accurate inference of the energies of these cosmic rays requires understanding the transmission/reflection of radio wave signals across the ice-air boundary. Satellite-based measurements of Antarctic surface reflectivity, using a co-located transmitter and receiver, have been performed more-or-less continuously for the last few decades. Our comparison of four different reflectivity surveys, at frequencies ranging from 2 to 45GHz and at near-normal incidence, yield generally consistent maps of high versus low reflectivity, as a function of location, across Antarctica. Using the Sun as an RF source, and the ANITA-3 balloon borne radio-frequency antenna array as the RF receiver, we have also measured the surface reflectivity over the interval 200-1000MHz, at elevation angles of 12-30∘. Consistent with our previous measurement using ANITA-2, we find good agreement, within systematic errors (dominated by antenna beam width uncertainties) and across Antarctica, with the expected reflectivity as prescribed by the Fresnel equations. To probe low incidence angles, inaccessible to the Antarctic Solar technique and not probed by previous satellite surveys, a novel experimental approach (“HiCal-1”) was devised. Unlike previous measurements, HiCal-ANITA constitute a bi-static transmitter-receiver pair separated by hundreds of kilometers. Data taken with HiCal, between 200 and 600MHz shows a significant departure from the Fresnel equations, constant with frequency over that band, with the deficit increasing with obliquity of incidence, which we attribute to the combined effects of possible surface roughness, surface grain effects, radar clutter and/or shadowing of the reflection zone due to Earth

  10. Energy loss of MeV protons specularly reflected from metal surfaces

    International Nuclear Information System (INIS)

    Juaristi, J.I.; Garcia de Abajo, F.J.; Echenique, P.M.

    1996-01-01

    A parameter-free model is presented to study the energy loss of fast protons specularly reflected from metal surfaces. The contributions to the energy loss from excitation of valence-band electrons and ionization of localized target-atom electronic states are calculated separately. The former is calculated from the induced surface wake potential using linear response theory and the specular-reflection model, while the latter is calculated in the first Born approximation. The results obtained are in good agreement with available experimental data. However, the experimental qualitative trend of the energy loss as a function of the angle of incidence is obtained when the valence-band electron model is replaced by localized target atom electron states, though with a worse quantitative agreement. copyright 1996 The American Physical Society

  11. Plasmonic reflectance anisotropy spectroscopy of metal nanoparticles on a semiconductor surface

    Science.gov (United States)

    Kosobukin, V. A.; Korotchenkov, A. V.

    2016-12-01

    A theory of plasmonic differential anisotropic reflection of light from nanoparticles located near the interface between media is developed. The model of a monolayer consisting of identical ellipsoidal metal particles occupying sites of a rectangular lattice is investigated. Effective plasmonic polarizabilities of nanoparticles in the layer are calculated self-consistently using the Green's function technique in the quasipoint dipole approximation. The local-field effect caused by anisotropic dipole plasmons of particles in the layer and their image dipoles is taken into account. The lately observed resonant reflectance anisotropy spectra of indium nanoclusters on InAs surface are explained by the difference between frequencies of plasmons with the orthogonal polarizations in the surface plane. The difference between the plasmon frequencies is attributed to anisotropy of the particles shape or/and the layer structure; the signs of frequency difference for the two types of anisotropy being different.

  12. Glazed ceramic roof tiles: influence of surface features in the solar reflectance index

    International Nuclear Information System (INIS)

    Bortoli, Leitcia Silva de; Stapait, Camila Cristina; Marinoski, Deivis Luis; Fredel, Marcio Celso; Schabbach, Luciana M.

    2016-01-01

    In this study the influence of surface features of ceramic roof tiles in the solar reflectance index were evaluated. Two glazed ceramic roof tiles (type stoneware) with the same color (ivory) but with different appearance (matte and brilliant) were the focus of the analysis. The Solar Reflectance Index (SRI) of the roofs tiles were determined by the solar reflectance values (UV-VIS-NIR) and emittance, measured in laboratory. The samples showed SRI> 39 in accordance with LEED certification criteria (Leadership in Energy and Environmental Design), contributing to minimizing the Heat Island Effects. Although the matte roof tile shows a slightly higher SRI value (82) than the brilliant one (78), the results for the variables that composes the SRI value (reflectance and emittance) were very similar. Analysis of XRD, SEM and EDS performed on the surfaces of the two roofs indicated for the matte glaze the presence of microcrystals (with barium and zinc) that can contribute to the slightly highest value of SRI. The roughness (optical interferometer white light) and the brightness (brightness meter) of the samples were also measured. (author)

  13. Anomalous Quasiparticle Reflection from the Surface of a ^{3}He-^{4}He Dilute Solution.

    Science.gov (United States)

    Ikegami, Hiroki; Kim, Kitak; Sato, Daisuke; Kono, Kimitoshi; Choi, Hyoungsoon; Monarkha, Yuriy P

    2017-11-10

    A free surface of a dilute ^{3}He-^{4}He liquid mixture is a unique system where two Fermi liquids with distinct dimensions coexist: a three-dimensional (3D) ^{3}He Fermi liquid in the bulk and a two-dimensional (2D) ^{3}He Fermi liquid at the surface. To investigate a novel effect generated by the interaction between the two Fermi liquids, the mobility of a Wigner crystal of electrons formed on the free surface of the mixture is studied. An anomalous enhancement of the mobility, compared with the case where the 3D and 2D systems do not interact with each other, is observed. The enhancement is explained by the nontrivial reflection of 3D quasiparticles from the surface covered with the 2D ^{3}He system.

  14. Absorption and reflectivity of the lithium niobate surface masked with a graphene layer

    Directory of Open Access Journals (Sweden)

    O. Salas

    2017-01-01

    Full Text Available We performed simulations of the interaction of a graphene layer with the surface of lithium niobate utilizing density functional theory and molecular dynamics at 300K and atmospheric pressure. We found that the graphene layer is physisorbed on the lithium niobate surface with an adsorption energy of -0.8205 eV/(carbon-atom. Subsequently, the energy band structure, the optical absorption and reflectivity of the new system were calculated. We found important changes in these physical properties with respect to the corresponding ones of a graphene layer and of a lithium niobate crystal.

  15. Observations of discrete energy loss effects in spectra of positrons reflected from solid surfaces

    International Nuclear Information System (INIS)

    Dale, J.M.; Hulett, L.D.; Pendyala, S.

    1980-01-01

    Surfaces of tungsten and silicon have been bombarded with monoenergetic beams of positrons and electrons. Spectra of reflected particles show energy loss tails with discrete peaks at kinetic energies about 15 eV lower than that of the elastic peaks. In the higher energy loss range for tungsten, positron spectra show fine structure that is not apparent in the electron spectra. This suggests that the positrons are losing energy through mechanisms different from that of the electrons

  16. Decadal changes of surface elevation over permafrost area estimated using reflected GPS signals

    Science.gov (United States)

    Liu, Lin; Larson, Kristine M.

    2018-02-01

    Conventional benchmark-based survey and Global Positioning System (GPS) have been used to measure surface elevation changes over permafrost areas, usually once or a few times a year. Here we use reflected GPS signals to measure temporal changes of ground surface elevation due to dynamics of the active layer and near-surface permafrost. Applying the GPS interferometric reflectometry technique to the multipath signal-to-noise ratio data collected by a continuously operating GPS receiver mounted deep in permafrost in Barrow, Alaska, we can retrieve the vertical distance between the antenna and reflecting surface. Using this unique kind of observables, we obtain daily changes of surface elevation during July and August from 2004 to 2015. Our results show distinct temporal variations at three timescales: regular thaw settlement within each summer, strong interannual variability that is characterized by a sub-decadal subsidence trend followed by a brief uplift trend, and a secular subsidence trend of 0.26 ± 0.02 cm year-1 during 2004 and 2015. This method provides a new way to fully utilize data from continuously operating GPS sites in cold regions for studying dynamics of the frozen ground consistently and sustainably over a long time.

  17. IRAS surface brightness maps of visible reflection nebulae: evidence for non-equilibrium infrared emission

    International Nuclear Information System (INIS)

    Castelaz, M.W.; Werner, M.W.; Sellgren, K.

    1986-01-01

    Surface brightness maps at 12, 25, 60, and 100 microns of 16 visible reflection nebulae were extracted from the Infrared Astronomy Satellite (IRAS) database. The maps were produced by coadding IRAS survey scans over areas centered on the illuminating stars, and have spatial resolutions of 0.9' x 4' at 12 and 25 microns, 1.8' x 4.5' at 60 microns, and 3.6' x 5' at 100 microns. Extended emission in the four IRAS bandpasses was detected in fourteen of the reflection nebulae. The IRAS data were used to measure the flux of the infrared emission associated with each source. The energy distributions show that the 12 micron flux is greater than the 25 micron flux in 11 of the nebulae, and the peak flux occurs in the 60 or 100 micron bandpass in all 16 nebular. The 60 and 100 micron flux can be approximated by blackbodies with temperatures between 30 and 50 K, consistent with temperatures expected from extrapolation of greybody fits to the 60 and 100 micron data. The excess 12 and 25 micron emission is attributed to a nonequilibrium process such as emission from thermal fluctuations of very small grains excited by single ultraviolet photons, or emission from polycyclic aromatic hydrocarbons (PAHs) excited by ultraviolet radiation. The common features of the energy distributions of the 16 reflection nebulae, also seen in the reflection nebulae associated with the Pleiades, suggest that PAHs or very small grains may be found in most reflection nebulae

  18. A fiber-coupled displacement measuring interferometer for determination of the posture of a reflective surface

    International Nuclear Information System (INIS)

    Mao, Shuai; Hu, Peng-Cheng; Ding, Xue-Mei; Tan, Jiu-Bin

    2016-01-01

    A fiber-coupled displacement measuring interferometer capable of determining of the posture of a reflective surface of a measuring mirror is proposed. The newly constructed instrument combines fiber-coupled displacement and angular measurement technologies. The proposed interferometer has advantages of both the fiber-coupled and the spatially beam-separated interferometer. A portable dual-position sensitive detector (PSD)-based unit within this proposed interferometer measures the parallelism of the two source beams to guide the fiber-coupling adjustment. The portable dual PSD-based unit measures not only the pitch and yaw of the retro-reflector but also measures the posture of the reflective surface. The experimental results of displacement calibration show that the deviations between the proposed interferometer and a reference one, Agilent 5530, at two different common beam directions are both less than ±35 nm, thus verifying the effectiveness of the beam parallelism measurement. The experimental results of angular calibration show that deviations of pitch and yaw with the auto-collimator (as a reference) are less than ±2 arc sec, thus proving the proposed interferometer’s effectiveness for determination of the posture of a reflective surface.

  19. Formation of reflective and conductive silver film on ABS surface via covalent grafting and solution spray

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dexin; Zhang, Yan [School of Mechanical and Automotive Engineering, South China University of Technology, 381 Wushan, Guangzhou 510640 (China); Bessho, Takeshi [Higashifuji Technical Center, Toyota Motor Corporation, 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Kudo, Takahiro; Sang, Jing; Hirahara, Hidetoshi; Mori, Kunio [Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Kang, Zhixin, E-mail: zxkang@scut.edu.cn [School of Mechanical and Automotive Engineering, South China University of Technology, 381 Wushan, Guangzhou 510640 (China)

    2015-09-15

    Highlights: • A pure and homogenous silver film was deposited by spray-style plating technique. • The mechanism of covalent bonding between coating and substrate was studied. • The silver coating is highly reflective and conductive. • UV light was used to activate the ABS surface with triazine azide derivative. - Abstract: Conductive and reflective silver layers on acrylonitrile butadiene styrene (ABS) plastics have been prepared by photo grafting of triazine azides upon ultraviolet activation, self-assembling of triazine dithiols and silver electroless plating by solution spray based on silver mirror reaction. The as-prepared silver film exhibited excellent adhesion with ABS owing to covalent bonds between coating and substrate, and the detailed bonding mechanism have been investigated by X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) result revealed that silver film on ABS was pure and with a nanocrystalline structure. Atomic force microscope (AFM) analysis demonstrated that massive silver particles with sizes varying from 80 to 120 nm were deposited on ABS and formed a homogenous and smooth coating, resulting in highly reflective surface. Furthermore, silver maintained its unique conductivity even as film on ABS surface in term of four-point probe method.

  20. Formation of reflective and conductive silver film on ABS surface via covalent grafting and solution spray

    International Nuclear Information System (INIS)

    Chen, Dexin; Zhang, Yan; Bessho, Takeshi; Kudo, Takahiro; Sang, Jing; Hirahara, Hidetoshi; Mori, Kunio; Kang, Zhixin

    2015-01-01

    Highlights: • A pure and homogenous silver film was deposited by spray-style plating technique. • The mechanism of covalent bonding between coating and substrate was studied. • The silver coating is highly reflective and conductive. • UV light was used to activate the ABS surface with triazine azide derivative. - Abstract: Conductive and reflective silver layers on acrylonitrile butadiene styrene (ABS) plastics have been prepared by photo grafting of triazine azides upon ultraviolet activation, self-assembling of triazine dithiols and silver electroless plating by solution spray based on silver mirror reaction. The as-prepared silver film exhibited excellent adhesion with ABS owing to covalent bonds between coating and substrate, and the detailed bonding mechanism have been investigated by X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) result revealed that silver film on ABS was pure and with a nanocrystalline structure. Atomic force microscope (AFM) analysis demonstrated that massive silver particles with sizes varying from 80 to 120 nm were deposited on ABS and formed a homogenous and smooth coating, resulting in highly reflective surface. Furthermore, silver maintained its unique conductivity even as film on ABS surface in term of four-point probe method

  1. Gain-Enhanced On-Chip Antenna Utilizing Artificial Magnetic Conductor Reflecting Surface at 94 GHz

    KAUST Repository

    Nafe, Mahmoud

    2015-08-04

    Nowadays, there is a growing demand for high frequency-bandwidth mm-wave (30-300 GHz) electronic wireless transceiver systems to support applications such as high data-rate wireless communication and high resolution imaging. Such mm-wave systems are becoming more feasible due to the extreme transistor downscaling in silicon-based integrated circuits, which enabled densely-integrated high-speed elec- tronics operating up to more than 100 GHz with low fabrication cost. To further enhance system integrability, it is required to implement all wireless system compo- nents on the chip. Presently, the last major barrier to true System-on-Chip (SoC) realization is the antenna implementation on the silicon chip. Although at mm-wave frequencies the antenna size becomes small enough to fit on chip, the antenna performance is greatly deteriorated due the high conductivity and high relative permittivity of the silicon substrate. The negative e↵ects of the silicon substrate could be avoided by using a metallic reflecting surface on top of silicon, which e↵ectively isolates the antenna from the silicon. However, this approach has the shortcoming of having to implement the antenna on the usually very thin silicon oxide layer of a typical CMOS fabrication process (10’s of μm). This forces the antenna to be in a very close proximity (less than one hundredth of a wavelength) to the reflecting surface. In this regime, the use of conventional metallic reflecting surface for silicon shielding has severe e↵ects on the antenna performance as it tends to reduce the antenna radiation resistance resulting in most of the energy being absorbed rather than radiated. In this work, the use of specially patterned reflecting surfaces for improving on- chip antenna performance is investigated. By using a periodic metallic surface on top of a grounded substrate, the structure can mimic the behavior of a perfect mag- netic conductor, hence called Artificial Magnetic Conductor (AMC) surface

  2. Surface Compositional Units on Mercury from Spectral Reflectance at Ultraviolet to Near-infrared Wavelengths

    Science.gov (United States)

    Izenberg, N. R.; Holsclaw, G. M.; Domingue, D. L.; McClintock, W. E.; Klima, R. L.; Blewett, D. T.; Helbert, J.; Head, J. W.; Sprague, A. L.; Vilas, F.; Solomon, S. C.

    2012-12-01

    The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft has been acquiring reflectance spectra of Mercury's surface for over 16 months. The Visible and Infrared Spectrograph (VIRS) component of MASCS has accumulated a global data set of more than 2 million spectra over the wavelength range 300-1450 nm. We have derived a set of VIRS spectral units (VSUs) from the following spectral parameters: visible brightness (R575: reflectance at 575 nm); visible/near-infrared reflectance ratio (VISr: reflectance at 415 nm to that at 750 nm); and ultraviolet reflectance ratio (UVr: reflectance at 310 nm to that at 390 nm). Five broad, slightly overlapping VSUs may be distinguished from these parameters. "Average VSU" areas have spectral parameters close to mean global values. "Dark blue VSU" areas have spectra with low R575 and high UVr. "Red VSU" areas have spectra with low UVr and higher VISr and R575 than average. "Intermediate VSU" areas have spectra with higher VISr than VSU red, generally higher R575, and a wide range of UVr. "Bright VSU" areas have high R575 and VISr and intermediate UVr. Several units defined by morphological or multispectral criteria correspond to specific VSUs, including low-reflectance material (dark blue VSU), pyroclastic deposits (red VSU), and hollows (intermediate VSU), but these VSUs generally include other types of areas as well. VSU definitions are complementary to those obtained by unsupervised clustering analysis. The global distribution of VIRS spectral units provides new information on Mercury's geological evolution. Much of Mercury's northern volcanic plains show spectral properties ranging from those of average VSU to those of red VSU, as does a large region in the southern hemisphere centered near 50°S, 245°E. Dark blue VSU material is widely distributed, with concentrations south of the northern plains, around the Rembrandt and

  3. IMPROVING IMAGE MATCHING BY REDUCING SURFACE REFLECTIONS USING POLARISING FILTER TECHNIQUES

    Directory of Open Access Journals (Sweden)

    N. Conen

    2018-05-01

    Full Text Available In dense stereo matching applications surface reflections may lead to incorrect measurements and blunders in the resulting point cloud. To overcome the problem of disturbing reflexions polarising filters can be mounted on the camera lens and light source. Reflections in the images can be suppressed by crossing the polarising direction of the filters leading to homogeneous illuminated images and better matching results. However, the filter may influence the camera’s orientation parameters as well as the measuring accuracy. To quantify these effects, a calibration and an accuracy analysis is conducted within a spatial test arrangement according to the German guideline VDI/VDE 2634.1 (2002 using a DSLR with and without polarising filter. In a second test, the interior orientation is analysed in more detail. The results do not show significant changes of the measuring accuracy in object space and only very small changes of the interior orientation (Δc ≤ 4 μm with the polarising filter in use. Since in medical applications many tiny reflections are present and impede robust surface measurements, a prototypic trinocular endoscope is equipped with polarising technique. The interior and relative orientation is determined and analysed. The advantage of the polarising technique for medical image matching is shown in an experiment with a moistened pig kidney. The accuracy and completeness of the resulting point cloud can be improved clearly when using polarising filters. Furthermore, an accuracy analysis using a laser triangulation system is performed and the special reflection properties of metallic surfaces are presented.

  4. Factors influencing the surface quality of polished tool steels

    International Nuclear Information System (INIS)

    Rebeggiani, S; Rosén, B-G

    2014-01-01

    Today’s demands on surface quality of moulds for injection moulding of plastic components involve no/low defect contents and roughness levels in the nm-range for high gloss applications. Material properties as well as operating conditions influence the mould finish, and thus the final surface of moulded products. This paper focuses on how particle content and different polishing strategies influence final surface qualities of moulds. Visual estimations of polished tool steel samples were combined with non-contact 3D-surface texture analysis in order to correlate traditional assessments to more quantitative methods, and to be able to analyse the surfaces at nanometre-level. It was found that steels with a lower proportion of particles, like carbides and oxides, gave rise to smoother polished surfaces. In a comparative study of polishers from different polishing shops, it was found that while different surface preparation strategies can lead to similar final roughness, similar preparation techniques can produce high-quality surfaces from different steel grades. However, the non-contact 3D-surface texture analysis showed that not all smooth polished surfaces have desirable functional topographies for injection moulding of glossy plastic components. (paper)

  5. Determining surface coverage of ultra-thin gold films from X-ray reflectivity measurements

    International Nuclear Information System (INIS)

    Kossoy, A.; Simakov, D.; Olafsson, S.; Leosson, K.

    2013-01-01

    The paper describes usage of X-ray reflectivity for characterization of surface coverage (i.e. film continuity) of ultra-thin gold films which are widely studied for optical, plasmonic and electronic applications. The demonstrated method is very sensitive and can be applied for layers below 1 nm. It has several advantages over other techniques which are often employed in characterization of ultra-thin metal films, such as optical absorption, Atomic Force Microscopy, Transmission Electron Microscopy or Scanning Electron Microscopy. In contrast to those techniques our method does not require specialized sample preparation and measurement process is insensitive to electrostatic charge and/or presence of surface absorbed water. We validate our results with image processing of Scanning Electron Microscopy images. To ensure precise quantitative analysis of the images we developed a generic local thresholding algorithm which allowed us to treat series of images with various values of surface coverage with similar image processing parameters. - Highlights: • Surface coverage/continuity of ultra-thin Au films (up to 7 nm) was determined. • Results from X-ray reflectivity were verified by scanning electron microscopy. • We developed local thresholding algorithm to treat non-homogeneous image contrast

  6. The impact of uncontrolled waste disposal on surface water quality ...

    African Journals Online (AJOL)

    The main threat to the surface water quality in Addis Ababa is environmental pollution derived from domestic and industrial activities. Due to the inadequacy of controlled waste management strategies and waste treatment plants, people are forced to discharge wastes both on open surface and within water bodies.

  7. Surface reflectance drives nest box temperature profiles and thermal suitability for target wildlife.

    Directory of Open Access Journals (Sweden)

    Stephen R Griffiths

    Full Text Available Thermal properties of tree hollows play a major role in survival and reproduction of hollow-dependent fauna. Artificial hollows (nest boxes are increasingly being used to supplement the loss of natural hollows; however, the factors that drive nest box thermal profiles have received surprisingly little attention. We investigated how differences in surface reflectance influenced temperature profiles of nest boxes painted three different colors (dark-green, light-green, and white: total solar reflectance 5.9%, 64.4%, and 90.3% respectively using boxes designed for three groups of mammals: insectivorous bats, marsupial gliders and brushtail possums. Across the three different box designs, dark-green (low reflectance boxes experienced the highest average and maximum daytime temperatures, had the greatest magnitude of variation in daytime temperatures within the box, and were consistently substantially warmer than light-green boxes (medium reflectance, white boxes (high reflectance, and ambient air temperatures. Results from biophysical model simulations demonstrated that variation in diurnal temperature profiles generated by painting boxes either high or low reflectance colors could have significant ecophysiological consequences for animals occupying boxes, with animals in dark-green boxes at high risk of acute heat-stress and dehydration during extreme heat events. Conversely in cold weather, our modelling indicated that there are higher cumulative energy costs for mammals, particularly smaller animals, occupying light-green boxes. Given their widespread use as a conservation tool, we suggest that before boxes are installed, consideration should be given to the effect of color on nest box temperature profiles, and the resultant thermal suitability of boxes for wildlife, particularly during extremes in weather. Managers of nest box programs should consider using several different colors and installing boxes across a range of both orientations and

  8. Simulation calculations of physical sputtering and reflection coefficient of plasma-irradiated carbon surface

    International Nuclear Information System (INIS)

    Kawamura, T.; Ono, T.; Yamamura, Y.

    1994-08-01

    Physical sputtering yields from the carbon surface irradiated by the boundary plasma are obtained with the use of a Monte Carlo simulation code ACAT. The yields are calculated for many random initial energy and angle values of incident protons or deuterons with a Maxwellian velocity distribution, and then averaged. Here the temperature of the boundary plasma, the sheath potential and the angle δ between the magnetic field line and the surface normal are taken into account. A new fitting formula for an arrangement of the numerical data of sputtering yield is introduced, in which six fitting parameters are determined from the numerical results and listed. These results provide a way to estimate the erosion of carbon materials irradiated by boundary plasma. The particle reflection coefficients for deuterons and their neutrals from a carbon surface are also calculated by the same code and presented together with, for comparison, that for the case of monoenergetic normal incidence. (author)

  9. Accounting for surface reflectance in the derivation of vertical column densities of NO2 from airborne imaging DOAS

    Science.gov (United States)

    Meier, Andreas Carlos; Schönhardt, Anja; Richter, Andreas; Bösch, Tim; Seyler, André; Constantin, Daniel Eduard; Shaiganfar, Reza; Merlaud, Alexis; Ruhtz, Thomas; Wagner, Thomas; van Roozendael, Michel; Burrows, John. P.

    2016-04-01

    Nitrogen oxides, NOx (NOx = NO + NO2) play a key role in tropospheric chemistry. In addition to their directly harmful effects on the respiratory system of living organisms, they influence the levels of tropospheric ozone and contribute to acid rain and eutrophication of ecosystems. As they are produced in combustion processes, they can serve as an indicator for anthropogenic air pollution. In the late summers of 2014 and 2015, two extensive measurement campaigns were conducted in Romania by several European research institutes, with financial support from ESA. The AROMAT / AROMAT-2 campaigns (Airborne ROmanian Measurements of Aerosols and Trace gases) were dedicated to measurements of air quality parameters utilizing newly developed instrumentation at state-of-the-art. The experiences gained will help to calibrate and validate the measurements taken by the upcoming Sentinel-S5p mission scheduled for launch in 2016. The IUP Bremen contributed to these campaigns with its airborne imaging DOAS (Differential Optical Absorption Spectroscopy) instrument AirMAP (Airborne imaging DOAS instrument for Measurements of Atmospheric Pollution). AirMAP allows retrieving spatial distributions of trace gas columns densities in a stripe below the aircraft. The measurements have a high spatial resolution of approximately 30 x 80 m2 (along x across track) at a typical flight altitude of 3000 m. Supported by the instrumental setup and the large swath, gapless maps of trace gas distributions above a large city, like Bucharest or Berlin, can be acquired within a time window of approximately two hours. These properties make AirMAP a valuable tool for the validation of trace gas measurements from space. DOAS retrievals yield the density of absorbers integrated along the light path of the measurement. The light path is altered with a changing surface reflectance, leading to enhanced / reduced slant column densities of NO2 depending on surface properties. This effect must be considered in

  10. Stormwater Priority Pollutants Versus Surface Water Quality Criteria

    DEFF Research Database (Denmark)

    Eriksson, Eva; Ledin, Anna; Baun, Anders

    2011-01-01

    Stormwater in urban areas comprises of a substantial part of the urban water cycle, dominating the flow in many small urban streams, and the pollution levels are sizeable. No stormwater quality criteria were found here and no European or national emission limit values exist. Stormwater pollutants...... however are present in levels exceeding most of the regulated surface water quality criteria and environmental quality standards. Therefore catchment characterisation is needed to chose suitable treatment prior to discharge into receiving surface waters, as the mixing may be insufficient in small streams....

  11. Quality-control design for surface-water sampling in the National Water-Quality Network

    Science.gov (United States)

    Riskin, Melissa L.; Reutter, David C.; Martin, Jeffrey D.; Mueller, David K.

    2018-04-10

    The data-quality objectives for samples collected at surface-water sites in the National Water-Quality Network include estimating the extent to which contamination, matrix effects, and measurement variability affect interpretation of environmental conditions. Quality-control samples provide insight into how well the samples collected at surface-water sites represent the true environmental conditions. Quality-control samples used in this program include field blanks, replicates, and field matrix spikes. This report describes the design for collection of these quality-control samples and the data management needed to properly identify these samples in the U.S. Geological Survey’s national database.

  12. Tool steel quality and surface finishing of plastic molds

    Directory of Open Access Journals (Sweden)

    Rafael Agnelli Mesquita

    2010-01-01

    Full Text Available Plastic industry is today in a constant growth, demanding several products from other segments, which includes the plastic molds, mainly used in the injection molding process. Considering all the requirements of plastic molds, the surface finishing is of special interest, as the injected plastic part is able to reproduce any details (and also defects from the mold surface. Therefore, several aspects on mold finishing are important, mainly related to manufacturing conditions - machining, grinding, polishing and texturing, and also related to the tool steel quality, in relation to microstructure homogeneity and non-metallic inclusions (cleanliness. The present paper is then focused on this interrelationship between steel quality and manufacturing process, which are both related to the final quality of plastic mold surfaces. Examples are discussed in terms of surface finishing of plastic molds and the properties or the microstructure of mold steels.

  13. To what extent do food purchases reflect shoppers? diet quality and nutrient intake?

    OpenAIRE

    Appelhans, Bradley M.; French, Simone A.; Tangney, Christy C.; Powell, Lisa M.; Wang, Yamin

    2017-01-01

    Background Food purchasing is considered a key mediator between the food environment and eating behavior, and food purchasing patterns are increasingly measured in epidemiologic and intervention studies. However, the extent to which food purchases actually reflect individuals? dietary intake has not been rigorously tested. This study examined cross-sectional agreement between estimates of diet quality and nutrient densities derived from objectively documented household food purchases and thos...

  14. Mathematical Modeling of Radiant Heat Transfer in Mirror Systems Considering Deep Reflecting Surface Defects

    Directory of Open Access Journals (Sweden)

    V. V. Leonov

    2014-01-01

    Full Text Available When designing large-sized mirror concentrating systems (MCS for high-temperature solar power plants, one must have at disposal reasonably reliable and economical methods and tools, making it possible to analyze its characteristics, to predict them depending on the operation conditions and accordingly to choose the most suitable system for the solution of particular task.Experimental determination of MCS characteristics requires complicated and expensive experimentation, having significant limitations on interpretation of the results, as well as limitations imposed due to the size of the structure. Therefore it is of particular interest to develop a mathematical model capable of estimating power characteristics of MCS considering the influence of operating conditions, design features, roughness and other surface defects.For efficient solution of the tasks the model must ensure simulation of solar radiant flux as well as simulation of geometrical and optical characteristics of reflection surface and their interaction. In this connection a statistical mathematical model of radiation heat exchange based on use of Monte Carlo methods and Finite Element Method was developed and realized in the software complex, making it possible to determine main characteristics of the MCS.In this paper the main attention is given to definition of MCS radiation characteristics with account for deep reflecting surface defects (cavities, craters. Deep cavities are not typical for MCS, but their occurrence is possible during operation as a result of erosion or any physical damage. For example, for space technology it is primarily micrometeorite erosion.

  15. Surface qualities after chemical-mechanical polishing on thin films

    International Nuclear Information System (INIS)

    Fu, Wei-En; Lin, Tzeng-Yow; Chen, Meng-Ke; Chen, Chao-Chang A.

    2009-01-01

    Demands for substrate and film surface planarizations significantly increase as the feature sizes of Integrated Circuit (IC) components continue to shrink. Chemical Mechanical Polishing (CMP), incorporating chemical and mechanical interactions to planarize chemically modified surface layers, has been one of the major manufacturing processes to provide global and local surface planarizations in IC fabrications. Not only is the material removal rate a concern, the qualities of the CMP produced surface are critical as well, such as surface finish, defects and surface stresses. This paper is to examine the CMP produced surface roughness on tungsten or W thin films based on the CMP process conditions. The W thin films with thickness below 1000 nm on silicon wafer were chemical-mechanical polished at different down pressures and platen speeds to produce different surface roughness. The surface roughness measurements were performed by an atomic force microscope (DI D3100). Results show that the quality of surface finish (R a value) is determined by the combined effects of down pressures and platen speeds. An optimal polishing condition is, then, possible for selecting the down pressures and platen speeds.

  16. Estimating the Augmented Reflectance Ratio of the Ocean Surface When Whitecaps Appear

    Directory of Open Access Journals (Sweden)

    Zhantang Xu

    2015-10-01

    Full Text Available The presence of foam influences the accuracy of satellite-derived water-leaving radiance. A model has been developed to estimate the augmented reflectance ratio (A(λ,U due to differences in the fraction of whitecap coverage (w on the ocean surface. A(λ,U can be calculated from the product of w and ρ(λ,U, where ρ(λ,U is the augmented ratio of the reflectance of background water (Rb(λ caused by the presence of whitecaps. Our results showed that the average A(400~700,U in the visible region was approximately 1.3% at U = 9 m∙s−1, 2.2% at U = 10 m∙s−1, 4.4% at U = 12 m∙s−1, 7.4% at U = 14 m∙s−1, 19% at U = 19 m∙s−1 and 37.9% at U = 24 m∙s−1, making it is necessary to consider the augmented reflectance ratio for remote sensing applications. By estimating remote sensing augmented reflectance using A(λ,U, it was found that the result was in good agreement with previous studies conducted in other areas with U from 9 to 12 m∙s−1. Since Rb(λ is temporally and spatially variable, our model considered the variation of Rb(λ, whereas existing models have assumed that Rb(λ is constant. Therefore, the proposed model is more suitable for estimating the augmented reflectance ratio due to whitecaps.

  17. Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chen Li [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen (Germany); Ueta, Hirokazu; Beck, Rainer D. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne (Switzerland); Bisson, Regis [Aix-Marseille Universite, PIIM, CNRS, UMR 7345, 13397 Marseille (France)

    2013-05-15

    We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies of gas/surface reaction dynamics combining optical state-specific reactant preparation in a molecular beam by rapid adiabatic passage with detection of surface-bound reaction products by reflection absorption infrared spectroscopy (RAIRS). RAIRS is a non-invasive infrared spectroscopic detection technique that enables online monitoring of the buildup of reaction products on the target surface during reactant deposition by a molecular beam. The product uptake rate obtained by calibrated RAIRS detection yields the coverage dependent state-resolved reaction probability S({theta}). Furthermore, the infrared absorption spectra of the adsorbed products obtained by the RAIRS technique provide structural information, which help to identify nascent reaction products, investigate reaction pathways, and determine branching ratios for different pathways of a chemisorption reaction. Measurements of the dissociative chemisorption of methane on Pt(111) with this new apparatus are presented to illustrate the utility of RAIRS detection for highly detailed studies of chemical reactions at the gas/surface interface.

  18. Capabilities of using white x-rays for the reconstruction of surface morphology from coherent reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Sant, Tushar, E-mail: tushar@physik.uni-siegen.de [Solid State Physics Group, University of Siegen, 57068 Siegen (Germany); Panzner, Tobias [Paul Scherrer Institute (Switzerland); Pietsch, Ullrich [Solid State Physics Group, University of Siegen, 57068 Siegen (Germany)

    2010-10-15

    We present a new method to reconstruct the surface profile of a sample from coherent reflectivity data of a white x-ray beam experiment. As an example the surface profile of a laterally confined silicon wafer has been reconstructed quantitatively from static speckle measurements using white coherent x-rays from a bending magnet in the energy range between 5 < E < 20 keV. As a consequence of using white radiation, speckles appear in addition to the Airy pattern caused by scattering at the entrance pinhole. Nevertheless, the surface profile of a triangularly shaped specimen was reconstructed considering sufficient oversampling between the beam-footprint and the effective sample width. For the profile reconstruction the Error-Reduction phase retrieval algorithm was modified by including the spectral illumination function and a Fresnel propagator term. The simultaneous use of different x-ray energies having different penetration depth provides information on the evolution of the surface profile from the near-surface towards the bulk. The limitations of present experiment can be overcome using white or pink radiation from a source with higher photon flux.

  19. The conditions for total reflection of low-energy atoms from crystal surfaces

    International Nuclear Information System (INIS)

    Hou, M.; Robinson, M.T.

    1978-01-01

    The critical angles for the total reflection of low-energy particles from Cu rows and (001) planes have been investigated, using the binary collision approximation computer simulation code MARLOWE Breakthrough angles were evaluated for H, N, Ne, Ar, Cu, Xe, and Au in the energy range from 0.1 to 7.5 keV. In both the axial and the planar cases, recoiling of the target atoms lowers the energy barrier which the target surface presents to the heavy projectiles. Consequently, the breakthrough angles are reduced for heavy projectiles below the values expected either from observations on light projectiles or from analytical channeling theory. (orig.) [de

  20. Assessment of Satellite-Derived Surface Reflectances by NASA's CAR Airborne Radiometer over Railroad Valley, Nevada

    Science.gov (United States)

    Kharbouche, Said; Muller, Jan-Peter; Gatebe, Charles K.; Scanlon, Tracy; Banks, Andrew C.

    2017-01-01

    CAR (Cloud Absorption Radiometer) is a multi-angular and multi-spectral airborne radiometer instrument, whose radiometric and geometric characteristics are well calibrated and adjusted before and after each flight campaign. CAR was built by NASA (National Aeronautics and Space Administration) in 1984. On 16 May 2008, a CAR flight campaign took place over the well-known calibration and validation site of Railroad Valley in Nevada (38.504 deg N, 115.692 deg W).The campaign coincided with the overpasses of several key EO (Earth Observation) satellites such as Landsat-7, Envisat and Terra. Thus, there are nearly simultaneous measurements from these satellites and the CAR airborne sensor over the same calibration site. The CAR spectral bands are close to those of most EO satellites. CAR has the ability to cover the whole range of azimuth view angles and a variety of zenith angles depending on altitude and, as a consequence, the biases seen between satellite and CAR measurements due to both unmatched spectral bands and unmatched angles can be significantly reduced. A comparison is presented here between CARs land surface reflectance (BRF or Bidirectional Reflectance Factor) with those derived from Terra/MODIS (MOD09 and MAIAC), Terra/MISR, Envisat/MERIS and Landsat-7. In this study, we utilized CAR data from low altitude flights (approx. 180 m above the surface) in order to minimize the effects of the atmosphere on these measurements and then obtain a valuable ground-truth data set of surface reflectance. Furthermore, this study shows that differences between measurements caused by surface heterogeneity can be tolerated, thanks to the high homogeneity of the study site on the one hand, and on the other hand, to the spatial sampling and the large number of CAR samples. These results demonstrate that satellite BRF measurements over this site are in good agreement with CAR with variable biases across different spectral bands. This is most likely due to residual aerosol

  1. Highly directive Fabry-Perot leaky-wave nanoantennas based on optical partially reflective surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lorente-Crespo, M.; Mateo-Segura, C., E-mail: C.Mateo-Segura@hw.ac.uk [Institute of Sensors, Signals and Systems, Heriot-Watt University, EH14 4AS Edinburgh (United Kingdom)

    2015-05-04

    Nanoantennas enhance the conversion between highly localized electromagnetic fields and far-field radiation. Here, we investigate the response of a nano-patch partially reflective surface backed with a silver mirror to an optical source embedded at the centre of the structure. Using full wave simulations, we demonstrate a two orders of magnitude increased directivity compared to the isotropic radiator, 50% power confinement to a 13.8° width beam and a ±16 nm bandwidth. Our antenna does not rely on plasmonic phenomena thus reducing non-radiative losses and conserving source coherence.

  2. Development and applications of retro-reflective surfaces for ultrasound in LBE

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    pulse or a complete absence of a reflection like a shadow. In that way, it suffices to align the sensor with the diaphragm instead of the fuel assembly which is much easier to achieve as the robotics on which the sensor is mounted move parallel with the diaphragm. The alignment requirement in the latter approach can be further relaxed by using a tiling of retro-reflectors on the lower surface of the diaphragm. In that way, alignment becomes less vital and the main source of acoustic energy loss - geometric spread of the beam - is almost completely removed, leaving only absorption losses. In this paper, we present the first results in developing a retro reflectance surface for ultrasound in LBE. We present experimental results for different designs of retro-reflectors in both water and LBE. We discuss both linear and array retro-reflectors of different sizes and investigate the influence of the main relevant ultrasonic parameters such as wavelength and spot size on the strength of the received reflection under different alignment angles. We also demonstrate how retro-reflective surfaces can be exploited when localizing objects using linear and rotating scanning methods. (authors)

  3. Scanning tunnel microscopic image of tungsten (100) and (110) real surfaces and nature of conduction electron reflection

    International Nuclear Information System (INIS)

    Pryadkin, S.L.; Tsoj, V.S.

    1988-01-01

    The electrically polished (100) and (110) surfaces of tungsten are studied with the aid of a scanning tunnel microscope at atmospheric pressure. The (110) surface consists of a large number of atomically plane terraces whereas the (100) surface is faceted. The scanning tunnel microscope data can explain such results of experiments on transverse electron focussing as the strong dependence of the probability for specular reflection of conduction electrons scattered by the (100) surface on the electron de Broglie wavelength and the absence of a dependence of the probability for specular reflection on the wavelength for the (110) surface

  4. Regional-Scale Surface Magnetic Fields and Proton Fluxes to Mercury's Surface from Proton-Reflection Magnetometry

    Science.gov (United States)

    Winslow, R. M.; Johnson, C. L.; Anderson, B. J.; Gershman, D. J.; Raines, J. M.; Lillis, R. J.; Korth, H.; Slavin, J. A.; Solomon, S. C.; Zurbuchen, T.

    2014-12-01

    The application of a recently developed proton-reflection magnetometry technique to MESSENGER spacecraft observations at Mercury has yielded two significant findings. First, loss-cone observations directly confirm particle precipitation to Mercury's surface and indicate that solar wind plasma persistently bombards the planet not only in the magnetic cusp regions but over a large fraction of the southern hemisphere. Second, the inferred surface field strengths independently confirm the north-south asymmetry in Mercury's global magnetic field structure first documented from observations of magnetic equator crossings. Here we extend this work with 1.5 additional years of observations (i.e., to 2.5 years in all) to further probe Mercury's surface magnetic field and better resolve proton flux precipitation to the planet's surface. We map regions where proton loss cones are observed; these maps indicate regions where protons precipitate directly onto the surface. The augmentation of our data set over that used in our original study allows us to examine the proton loss cones in cells of dimension 10° latitude by 20° longitude in Mercury body-fixed coordinates. We observe a transition from double-sided to single-sided loss cones in the pitch-angle distributions; this transition marks the boundary between open and closed field lines. At the surface this boundary lies between 60° and 70°N. Our observations allow the estimation of surface magnetic field strengths in the northern cusp region and the calculation of incident proton fluxes to both hemispheres. In the northern cusp, our regional-scale observations are consistent with an offset dipole field and a dipole moment of 190 nT RM3, where RM is Mercury's radius, implying that any regional-scale variations in surface magnetic field strengths are either weak relative to the dipole field or occur at length scales smaller than the resolution of our observations (~300 km). From the global proton flux map (north of 40° S

  5. Barium fluoride surface preparation, analysis and UV reflective coatings at Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Wuest, C.R.

    1992-01-01

    Lawrence Livermore National Laboratory (LLNL) has begun a program of study on barium fluoride scintillating crystals for the Barium Fluoride Electromagnetic Calorimeter Collaboration. This program has resulted in a number of significant improvements in the mechanical processing, polishing and coating of barium fluoride crystals. Techniques have been developed using diamond-loaded pitch lapping that can produce 15 angstrom RMS surface finishes over large areas. These lapped surfaces have been shown to be crystalline using Rutherford Back-scattering (RBS). Also, special polishing fixtures have been designed based on mounting technology developed for the 1.1 m diameter optics used in LLNL's Nova Laser. These fixtures allow as many as five 25--50 cm long barium fluoride crystals to be polished and lapped at a time with the necessary tolerances for the 16,000 crystal Barium Fluoride Calorimeter. In addition, results will be presented on coating barium fluoride with UV reflective layers of magnesium fluoride and aluminum

  6. Modified polarimetric bidirectional reflectance distribution function with diffuse scattering: surface parameter estimation

    Science.gov (United States)

    Zhan, Hanyu; Voelz, David G.

    2016-12-01

    The polarimetric bidirectional reflectance distribution function (pBRDF) describes the relationships between incident and scattered Stokes parameters, but the familiar surface-only microfacet pBRDF cannot capture diffuse scattering contributions and depolarization phenomena. We propose a modified pBRDF model with a diffuse scattering component developed from the Kubelka-Munk and Le Hors et al. theories, and apply it in the development of a method to jointly estimate refractive index, slope variance, and diffuse scattering parameters from a series of Stokes parameter measurements of a surface. An application of the model and estimation approach to experimental data published by Priest and Meier shows improved correspondence with measurements of normalized Mueller matrix elements. By converting the Stokes/Mueller calculus formulation of the model to a degree of polarization (DOP) description, the estimation results of the parameters from measured DOP values are found to be consistent with a previous DOP model and results.

  7. Impact of initial surface parameters on the final quality of laser micro-polished surfaces

    Science.gov (United States)

    Chow, Michael; Bordatchev, Evgueni V.; Knopf, George K.

    2012-03-01

    Laser micro-polishing (LμP) is a new laser-based microfabrication technology for improving surface quality during a finishing operation and for producing parts and surfaces with near-optical surface quality. The LμP process uses low power laser energy to melt a thin layer of material on the previously machined surface. The polishing effect is achieved as the molten material in the laser-material interaction zone flows from the elevated regions to the local minimum due to surface tension. This flow of molten material then forms a thin ultra-smooth layer on the top surface. The LμP is a complex thermo-dynamic process where the melting, flow and redistribution of molten material is significantly influenced by a variety of process parameters related to the laser, the travel motions and the material. The goal of this study is to analyze the impact of initial surface parameters on the final surface quality. Ball-end micromilling was used for preparing initial surface of samples from H13 tool steel that were polished using a Q-switched Nd:YAG laser. The height and width of micromilled scallops (waviness) were identified as dominant parameter affecting the quality of the LμPed surface. By adjusting process parameters, the Ra value of a surface, having a waviness period of 33 μm and a peak-to-valley value of 5.9 μm, was reduced from 499 nm to 301 nm, improving the final surface quality by 39.7%.

  8. Analysing the impact of reflectance distributions and well geometries on vertical surface daylight levels in atria for overcast skies

    Energy Technology Data Exchange (ETDEWEB)

    Du, Jiangtao; Sharples, Steve [School of Architecture, University of Sheffield, Crookesmoor Building, Conduit Road, Sheffield S10 1FL (United Kingdom)

    2010-07-15

    This study investigated the impacts of different diffuse reflectance distributions and well geometries on vertical daylight factors and vertical internally reflected components in atria. Two forms of reflectance distribution patterns of wall surface were examined: horizontal and vertical reflectance band variation. The square atrium models studied have a broader WI range of 0.25-2.0, which represent shallow, medium and high atria. Radiance, a powerful package based on backward ray tracing technique, was used for the simulations of vertical daylight levels. The results show that different reflectance distributions of square atrium walls do have an impact on the vertical daylight factors and vertical internally reflected components under overcast sky condition. The impact relates to the orientation of the band with different reflectance distributions on the wall. Compared with the vertical band surface, the horizontal band surface has a much more complicated effect. The horizontal distributions of the reflectances significantly affects the vertical daylight levels at the locations more than 30% atrium height on the wall. For an atrium with a height more than 1/2 the width, the effect tends to increase with the increasing well index. The vertical distributions of the reflectance, nevertheless, do not substantially take effect on the vertical daylight levels in atria except for some special reflectance distribution patterns. (author)

  9. Surface quality monitoring for process control by on-line vibration analysis using an adaptive spline wavelet algorithm

    Science.gov (United States)

    Luo, G. Y.; Osypiw, D.; Irle, M.

    2003-05-01

    The dynamic behaviour of wood machining processes affects the surface finish quality of machined workpieces. In order to meet the requirements of increased production efficiency and improved product quality, surface quality information is needed for enhanced process control. However, current methods using high price devices or sophisticated designs, may not be suitable for industrial real-time application. This paper presents a novel approach of surface quality evaluation by on-line vibration analysis using an adaptive spline wavelet algorithm, which is based on the excellent time-frequency localization of B-spline wavelets. A series of experiments have been performed to extract the feature, which is the correlation between the relevant frequency band(s) of vibration with the change of the amplitude and the surface quality. The graphs of the experimental results demonstrate that the change of the amplitude in the selective frequency bands with variable resolution (linear and non-linear) reflects the quality of surface finish, and the root sum square of wavelet power spectrum is a good indication of surface quality. Thus, surface quality can be estimated and quantified at an average level in real time. The results can be used to regulate and optimize the machine's feed speed, maintaining a constant spindle motor speed during cutting. This will lead to higher level control and machining rates while keeping dimensional integrity and surface finish within specification.

  10. Anti-reflection textured structures by wet etching and island lithography for surface-enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Bo-Kai [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Cheng, Hsin-Hung [Department of Marine Engineering, Taipei College of Maritime Technology, Taipei 11174, Taiwan (China); Nien, Li-Wei; Chen, Miin-Jang [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Nagao, Tadaaki [Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Li, Jia-Han [Department of Engineering Science and Ocean Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Hsueh, Chun-Hway, E-mail: hsuehc@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2015-12-01

    Graphical abstract: - Highlights: • We fabricated textured SERS substrate with a high surface area and low reflectance. • Large surface area of substrate contains more gold nanodroplets to absorb analytes. • Low reflectance of textured SERS substrate enabled multiple reflections of incident laser light. • We obtained strong SERS enhancement from nanopillar-on-pyramid SERS substrate. - Abstract: A high surface area and low reflection textured surface-enhanced Raman scattering (SERS) substrate with plasmonic gold nanodroplets fabricated by wet etching and island lithography was reported in the present study. Specifically, four textured substrates, planar, pyramid, nanopillar, and nanopillar-on-pyramid, were fabricated. The fabricated structures were simulated using the finite-difference time-domain method and the results agreed with the reflection and dark-field scattering measurements. Although the SERS signals varied in different measured regions because of the random nanostructure, the SERS substrates with nanopillar-on-pyramid structure always have the stronger enhancement factor than the SERS substrates with only pyramids or nanopillars. Based on the atomic force microscope and reflection measurements, the nanopillar-on-pyramid structure provided a large surface area and multiple reflections for SERS enhancement, which was about 3 orders of magnitude larger than that of the planar substrate. Our results can be applied to fabricate the inexpensive, large surface area, and high SERS enhancement substrates.

  11. Estimation of Melt Ponds over Arctic Sea Ice using MODIS Surface Reflectance Data

    Science.gov (United States)

    Ding, Y.; Cheng, X.; Liu, J.

    2017-12-01

    Melt ponds over Arctic sea ice is one of the main factors affecting variability of surface albedo, increasing absorption of solar radiation and further melting of snow and ice. In recent years, a large number of melt ponds have been observed during the melt season in Arctic. Moreover, some studies have suggested that late spring to mid summer melt ponds information promises to improve the prediction skill of seasonal Arctic sea ice minimum. In the study, we extract the melt pond fraction over Arctic sea ice since 2000 using three bands MODIS weekly surface reflectance data by considering the difference of spectral reflectance in ponds, ice and open water. The preliminary comparison shows our derived Arctic-wide melt ponds are in good agreement with that derived by the University of Hamburg, especially at the pond distribution. We analyze seasonal evolution, interannual variability and trend of the melt ponds, as well as the changes of onset and re-freezing. The melt pond fraction shows an asymmetrical growth and decay pattern. The observed melt ponds fraction is almost within 25% in early May and increases rapidly in June and July with a high fraction of more than 40% in the east of Greenland and Beaufort Sea. A significant increasing trend in the melt pond fraction is observed for the period of 2000-2017. The relationship between melt pond fraction and sea ice extent will be also discussed. Key Words: melt ponds, sea ice, Arctic

  12. From Intensity Profile to Surface Normal: Photometric Stereo for Unknown Light Sources and Isotropic Reflectances.

    Science.gov (United States)

    Lu, Feng; Matsushita, Yasuyuki; Sato, Imari; Okabe, Takahiro; Sato, Yoichi

    2015-10-01

    We propose an uncalibrated photometric stereo method that works with general and unknown isotropic reflectances. Our method uses a pixel intensity profile, which is a sequence of radiance intensities recorded at a pixel under unknown varying directional illumination. We show that for general isotropic materials and uniformly distributed light directions, the geodesic distance between intensity profiles is linearly related to the angular difference of their corresponding surface normals, and that the intensity distribution of the intensity profile reveals reflectance properties. Based on these observations, we develop two methods for surface normal estimation; one for a general setting that uses only the recorded intensity profiles, the other for the case where a BRDF database is available while the exact BRDF of the target scene is still unknown. Quantitative and qualitative evaluations are conducted using both synthetic and real-world scenes, which show the state-of-the-art accuracy of smaller than 10 degree without using reference data and 5 degree with reference data for all 100 materials in MERL database.

  13. Collection and corrections of oblique multiangle hyperspectral bidirectional reflectance imagery of the water surface

    Science.gov (United States)

    Bostater, Charles R.; Oney, Taylor S.

    2017-10-01

    Hyperspectral images of coastal waters in urbanized regions were collected from fixed platform locations. Surf zone imagery, images of shallow bays, lagoons and coastal waters are processed to produce bidirectional reflectance factor (BRF) signatures corrected for changing viewing angles. Angular changes as a function of pixel location within a scene are used to estimate changes in pixel size and ground sampling areas. Diffuse calibration targets collected simultaneously from within the image scene provides the necessary information for calculating BRF signatures of the water surface and shorelines. Automated scanning using a pushbroom hyperspectral sensor allows imagery to be collected on the order of one minute or less for different regions of interest. Imagery is then rectified and georeferenced using ground control points within nadir viewing multispectral imagery via image to image registration techniques. This paper demonstrates the above as well as presenting how spectra can be extracted along different directions in the imagery. The extraction of BRF spectra along track lines allows the application of derivative reflectance spectroscopy for estimating chlorophyll-a, dissolved organic matter and suspended matter concentrations at or near the water surface. Imagery is presented demonstrating the techniques to identify subsurface features and targets within the littoral and surf zones.

  14. Airborne hyperspectral observations of surface and cloud directional reflectivity using a commercial digital camera

    Directory of Open Access Journals (Sweden)

    A. Ehrlich

    2012-04-01

    Full Text Available Spectral radiance measurements by a digital single-lens reflex camera were used to derive the directional reflectivity of clouds and different surfaces in the Arctic. The camera has been calibrated radiometrically and spectrally to provide accurate radiance measurements with high angular resolution. A comparison with spectral radiance measurements with the Spectral Modular Airborne Radiation measurement sysTem (SMART-Albedometer showed an agreement within the uncertainties of both instruments (6% for both. The directional reflectivity in terms of the hemispherical directional reflectance factor (HDRF was obtained for sea ice, ice-free ocean and clouds. The sea ice, with an albedo of ρ = 0.96 (at 530 nm wavelength, showed an almost isotropic HDRF, while sun glint was observed for the ocean HDRF (ρ = 0.12. For the cloud observations with ρ = 0.62, the cloudbow – a backscatter feature typically for scattering by liquid water droplets – was covered by the camera. For measurements above heterogeneous stratocumulus clouds, the required number of images to obtain a mean HDRF that clearly exhibits the cloudbow has been estimated at about 50 images (10 min flight time. A representation of the HDRF as a function of the scattering angle only reduces the image number to about 10 (2 min flight time.

    The measured cloud and ocean HDRF have been compared to radiative transfer simulations. The ocean HDRF simulated with the observed surface wind speed of 9 m s−1 agreed best with the measurements. For the cloud HDRF, the best agreement was obtained by a broad and weak cloudbow simulated with a cloud droplet effective radius of Reff = 4 μm. This value agrees with the particle sizes derived from in situ measurements and retrieved from the spectral radiance of the SMART-Albedometer.

  15. Effect of surface treatment of tailings on effluent quality

    International Nuclear Information System (INIS)

    Murray, D.R.; Okuhara, D.

    1980-01-01

    Lysimeters containing 125 tons of mine tailings were used to determine the impact of gravel, sawdust, and vegetation as surface treatments on the quality and quantity of effluent produced from sulfide-containing uranium mill tailings. Over a 5-yr period, treatments did not alter the effluent quality to a level acceptable to regulatory requirements. The concentration of iron, copper, lead, aluminum, and sulfate increased with the rise of acidity during this period. However, the rate and extent of changes did vary with the treatment. The role of surface treatment in long-term waste abandonment must be investigated further

  16. Shale gas development impacts on surface water quality in Pennsylvania

    Science.gov (United States)

    Olmstead, Sheila M.; Muehlenbachs, Lucija A.; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J.

    2013-01-01

    Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl−) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl− concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl− concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases. PMID:23479604

  17. ChemCam passive reflectance spectroscopy of surface materials at the Curiosity landing site, Mars

    Science.gov (United States)

    Johnson, Jeffrey R.; Bell, J. F.; Bender, S.; Blaney, D.; Cloutis, E.; DeFlores, L.; Ehlmann, B.; Gasnault, O.; Gondet, B.; Kinch, K.; Lemmon, M.; Le Mouélic, S.; Maurice, S.; Rice, M.; Wiens, R. C.

    2015-03-01

    The spectrometers on the Mars Science Laboratory (MSL) ChemCam instrument were used in passive mode to record visible/near-infrared (400-840 nm) radiance from the martian surface. Using the onboard ChemCam calibration targets' housing as a reflectance standard, we developed methods to collect, calibrate, and reduce radiance observations to relative reflectance. Such measurements accurately reproduce the known reflectance spectra of other calibration targets on the rover, and represent the highest spatial resolution (0.65 mrad) and spectral sampling (rocks and soils match those from orbital observations and multispectral data from the MSL Mastcam camera. Preliminary analyses of the band depths, spectral slopes, and reflectance ratios of the more than 2000 spectra taken during the first year of MSL operations demonstrate at least six spectral classes of materials distinguished by variations in ferrous and ferric components. Initial comparisons of ChemCam spectra to laboratory spectra of minerals and Mars analog materials demonstrate similarities with palagonitic soils and indications of orthopyroxene in some dark rocks. Magnesium-rich "raised ridges" tend to exhibit distinct near-infrared slopes. The ferric absorption downturn typically found for martian materials at rocks and drill tailings, consistent with their more ferrous nature. Calcium-sulfate veins exhibit the highest relative reflectances observed, but are still relatively red owing to the effects of residual dust. Such dust is overall less prominent on rocks sampled within the "blast zone" immediately surrounding the landing site. These samples were likely affected by the landing thrusters, which partially removed the ubiquitous dust coatings. Increased dust coatings on the calibration targets during the first year of the mission were documented by the ChemCam passive measurements as well. Ongoing efforts to model and correct for this dust component should improve calibration of the relative reflectance

  18. OMI/Aura Surface Reflectance Climatology Level 3 Global 0.5deg Lat/Lon Grid V003

    Data.gov (United States)

    National Aeronautics and Space Administration — The OMI Earth Surface Reflectance Climatology product, OMLER (Global 0.5deg Lat/Lon grid) which is based on Version 003 Level-1B top of atmosphere upwelling radiance...

  19. Plasma surface reflectance spectroscopy for non-invasive and continuous monitoring of extracellular component of blood

    Science.gov (United States)

    Sakota, Daisuke; Takatani, Setsuo

    2012-04-01

    To achieve the quantitative optical non-invasive diagnosis of blood during extracorporeal circulation therapies, the instrumental technique to extract extracellular spectra from whole blood was developed. In the circuit, the continuous blood flow was generated by a centrifugal blood pump. The oxygen saturation was maintained 100% by an oxygenator. The developed glass optical flow cell was attached to the outlet tubing of the oxygenator. The halogen lamp including the light from 400 to 900 nm wavelength was used for the light source. The light was guided into an optical fiber. The light emitted by the fiber was collimated and emitted to the flow cell flat surface at the incident angle of 45 degrees. The light just reflected on the boundary between inner surface of the flow cell and plasma at 45 degrees was detected by the detection fiber. The detected light was analyzed by a spectral photometer. The obtained spectrum from 400 to 600nm wavelength was not changed with respect to the hematocrit. In contrast, the signal in the spectral range was changed when the plasma free hemoglobin increased. By using two spectral range, 505+/-5 nm and 542.5+/-2.5 nm, the differential spectrum was correlated with the free hemoglobin at R2=0.99. On the other hand, as for the hematocrit, the differential spectrum was not correlated at R2=0.01. Finally, the plasma free hemoglobin was quantified with the accuracy of 22+/-19mg/dL. The result shows that the developed plasma surface reflectance spectroscopy (PSRS) can extract the plasma spectrum from flowing whole blood.

  20. A prototype for automation of land-cover products from Landsat Surface Reflectance Data Records

    Science.gov (United States)

    Rover, J.; Goldhaber, M. B.; Steinwand, D.; Nelson, K.; Coan, M.; Wylie, B. K.; Dahal, D.; Wika, S.; Quenzer, R.

    2014-12-01

    Landsat data records of surface reflectance provide a three-decade history of land surface processes. Due to the vast number of these archived records, development of innovative approaches for automated data mining and information retrieval were necessary. Recently, we created a prototype utilizing open source software libraries for automatically generating annual Anderson Level 1 land cover maps and information products from data acquired by the Landsat Mission for the years 1984 to 2013. The automated prototype was applied to two target areas in northwestern and east-central North Dakota, USA. The approach required the National Land Cover Database (NLCD) and two user-input target acquisition year-days. The Landsat archive was mined for scenes acquired within a 100-day window surrounding these target dates, and then cloud-free pixels where chosen closest to the specified target acquisition dates. The selected pixels were then composited before completing an unsupervised classification using the NLCD. Pixels unchanged in pairs of the NLCD were used for training decision tree models in an iterative process refined with model confidence measures. The decision tree models were applied to the Landsat composites to generate a yearly land cover map and related information products. Results for the target areas captured changes associated with the recent expansion of oil shale production and agriculture driven by economics and policy, such as the increase in biofuel production and reduction in Conservation Reserve Program. Changes in agriculture, grasslands, and surface water reflect the local hydrological conditions that occurred during the 29-year span. Future enhancements considered for this prototype include a web-based client, ancillary spatial datasets, trends and clustering algorithms, and the forecasting of future land cover.

  1. VNIR Reflectance and MIR Emissivity Spectra of Ordinary Chondrite Meteorites Under Simulated Asteroid Surface Conditions

    Science.gov (United States)

    Gemma, M.; Shirley, K.; Glotch, T. D.; Ebel, D. S. S.

    2017-12-01

    Recent missions have revealed much about the nature of many Near-Earth asteroids, including the NEAR-Shoemaker target 433 Eros and Hayabusa target 25142 Itokawa. Both asteroids appear to have mineralogy consistent with ordinary chondrite meteorites. Laboratory spectral analysis of well-constrained meteorite samples can be employed as a reference tool to characterize and constrain data from current and future asteroid studies. A sample set of ordinary chondrite meteorites was chosen from the collection at the American Museum of Natural History. Six meteorites, spanning groups H, L, and LL, were prepared at four different size fractions (25-63 μm, 63-90 μm, 90-125 μm, 125-250 μm) in an attempt to mimic regolith known to exist on asteroids such as 433 Eros and 25142 Itokawa. At the Center for Planetary Exploration at Stony Brook University, spectra of the ordinary chondrite material were measured under simulated asteroid surface conditions ( 10-6 mbar, 150 K chamber temperature, low intensity illumination). The samples were used in two experiments: one measuring visible and near-infrared (VNIR) reflectance spectra at a series of temperatures, and the other measuring mid-infrared (MIR) emissivity spectra. The emissivity measurements require accurate simulation of the thermal environment within asteroid regolith, achieved by inducing a thermal gradient within the sample that results in a surface brightness temperature around 323 K (similar to the surface of 25142 Itokawa). Mid-IR emissivity spectra were collected for each sample at a surface temperature of 323 K, and reflectance spectra were collected in increments of 10 K, over the range 283 K to 373 K. Preliminary VNIR spectra show spreads similar to those seen in Hinrichs and Lucey (2002). Preliminary MIR emissivity spectra suggest that under asteroid surface conditions, the position of the Christiansen feature shifts to shorter wavelengths and emissivity is lower in the Reststrahlen bands when compared to

  2. X-ray Reflectivity Study of Ionic Liquids at Electrified Surfaces

    Science.gov (United States)

    Chu, Miaoqi

    X-ray reflectivity (XRR) versatile technique that characterize the surface structures. However, due to the lack of phase information of X-ray data, the reconstruction of electron density profile (EDP) from XRR data is an ill-posed inverse problem that requires extra attention. In Chapter 1, several key concepts in XRR data analysis are reviewed. The typical XRR data acquisition procedure and methods of modeling electron density are introduced. The widely used logarithm form of merit function is justified with mathematical deduction and numerical experiment. A scheme that generates artificial reflectivity data with theoretical statistical error but not systematical error is proposed. With the methods and schemes described in Chapter 1, simulated reflectivity data of a simple one-slab model is generated and fitted to test the efficient of EDP reconstruction. By isolating the parameters, the effects of slab width, electron density contrast and maximal wave transfer are studied individually. It?s demonstrated that best-fit/global minima, result reported by most XRR studies, don?t necessary reflect the real EDP. By contrast, mapping the merit function in the parametric space can capture much more details. Additionally, the widely accepted concept about the XRR theoretical spatial resolution (pi/q_{max}) as well the using Patterson function are brought to test. In the perspective of XRR data analysis, this chapter puts forward general rules to design and optimize XRR experiments. It also demonstrates how susceptible the fitting result will be if it?s not done carefully. In Chapter 3, the interface between hydrophobic OTS film and several solvents is studied with XRR in a transmission-cell setup. The solvents, from water, acetone, to alcohol (methanol, ethanol, 1-propanol), to alkane (pentane, hexane and heptane), vary significantly in terms of polarity and hydrogen bonding. However, the XRR data from different solvents are subtle. The methods and principles elicited in

  3. Near-surface, marine seismic-reflection data defines potential hydrogeologic confinement bypass in a tertiary carbonate aquifer, southeastern Florida

    Science.gov (United States)

    Cunningham, Kevin J.; Walker, Cameron; Westcott, Richard L.

    2012-01-01

    Approximately 210 km of near-surface, high-frequency, marine seismic-reflection data were acquired on the southeastern part of the Florida Platform between 2007 and 2011. Many high-resolution, seismic-reflection profiles, interpretable to a depth of about 730 m, were collected on the shallow-marine shelf of southeastern Florida in water as shallow as 1 m. Landward of the present-day shelf-margin slope, these data image middle Eocene to Pleistocene strata and Paleocene to Pleistocene strata on the Miami Terrace. This high-resolution data set provides an opportunity to evaluate geologic structures that cut across confining units of the Paleocene to Oligocene-age carbonate rocks that form the Floridan aquifer system.Seismic profiles image two structural systems, tectonic faults and karst collapse structures, which breach confining beds in the Floridan aquifer system. Both structural systems may serve as pathways for vertical groundwater flow across relatively low-permeability carbonate strata that separate zones of regionally extensive high-permeability rocks in the Floridan aquifer system. The tectonic faults occur as normal and reverse faults, and collapse-related faults have normal throw. The most common fault occurrence delineated on the reflection profiles is associated with karst collapse structures. These high-frequency seismic data are providing high quality structural analogs to unprecedented depths on the southeastern Florida Platform. The analogs can be used for assessment of confinement of other carbonate aquifers and the sealing potential of deeper carbonate rocks associated with reservoirs around the world.

  4. Neutron reflectivity study of substrate surface chemistry effects on supported phospholipid bilayer formation on (1120) sapphire.

    Energy Technology Data Exchange (ETDEWEB)

    Oleson, Timothy A. [University of Wisconsin, Madison; Sahai, Nita [University of Akron; Wesolowski, David J [ORNL; Dura, Joseph A [ORNL; Majkrzak, Charles F [ORNL; Giuffre, Anthony J. [University of Wisconsin, Madison

    2012-01-01

    Oxide-supported phospholipid bilayers (SPBs) used as biomimetric membranes are significant for a broad range of applications including improvement of biomedical devices and biosensors, and in understanding biomineralization processes and the possible role of mineral surfaces in the evolution of pre-biotic membranes. Continuous-coverage and/or stacjed SPBs retain properties (e.,g. fluidity) more similar to native biological membranes, which is desirable for most applications. Using neutron reflectivity, we examined face coverage and potential stacking of dipalmitoylphosphatidylcholine (DPPC) bilayers on the (1120) face of sapphire (a-Al2O3). Nearly full bilayers were formed at low to neutral pH, when the sapphire surface is positively charged, and at low ionic strength (l=15 mM NaCl). Coverage decreased at higher pH, close to the isoelectric point of sapphire, and also at high I>210mM, or with addition of 2mM Ca2+. The latter two effects are additive, suggesting that Ca2+ mitigates the effect of higher I. These trends agree with previous results for phospholipid adsorption on a-Al2O3 particles determined by adsorption isotherms and on single-crystal (1010) sapphire by atomic force microscopy, suggesting consistency of oxide surface chemistry-dependent effects across experimental techniques.

  5. Different size biomolecules anchoring on porous silicon surface: fluorescence and reflectivity pores infiltration comparative studies

    Energy Technology Data Exchange (ETDEWEB)

    Giovannozzi, Andrea M.; Rossi, Andrea M. [National Institute for Metrological Research, Thermodynamic Division, Strada delle Cacce 91, 10135 Torino (Italy); Renacco, Chiara; Farano, Alessandro [Ribes Ricecrhe Srl, Via Lavoratori Vittime del Col du Mont 24, 11100 Aosta (Italy); Derosas, Manuela [Biodiversity Srl, Via Corfu 71, 25124 Brescia (Italy); Enrico, Emanuele [National Institute for Metrological Research, Electromagnetism Division, Strada delle Cacce 91, 10135 Torino (Italy)

    2011-06-15

    The performance of porous silicon optical based biosensors strongly depends on material nanomorphology, on biomolecules distribution inside the pores and on the ability to link sensing species to the pore walls. In this paper we studied the immobilization of biomolecules with different size, such as antibody anti aflatoxin (anti Aflatox Ab, {proportional_to}150 KDa), malate dehydrogenase (MDH, {proportional_to}36KDa) and metallothionein (MT, {proportional_to}6KDa) at different concentrations on mesoporous silicon samples ({proportional_to}15 nm pores diameter). Fluorescence measurements using FITC- labeled biomolecules and refractive index analysis based on reflectivity spectra have been employed together to detect the amount of proteins bound to the surface and to evaluate their diffusion inside the pores. Here we suggest that these two techniques should be used together to have a better understanding of what happens at the porous silicon surface. In fact, when pores dimensions are not perfectly tuned to the protein size a higher fluorescence signal doesn't often correspond to a higher biomolecules distribution inside the pores. When a too much higher concentration of biomolecule is anchored on the surface, steric crowd effects and repulsive interactions probably take over and hinder pores infiltration, inducing a small or absent shift in the fringe pattern even if a higher fluorescence signal is registered. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Virtual-stereo fringe reflection technique for specular free-form surface testing

    Science.gov (United States)

    Ma, Suodong; Li, Bo

    2016-11-01

    Due to their excellent ability to improve the performance of optical systems, free-form optics have attracted extensive interest in many fields, e.g. optical design of astronomical telescopes, laser beam expanders, spectral imagers, etc. However, compared with traditional simple ones, testing for such kind of optics is usually more complex and difficult which has been being a big barrier for the manufacture and the application of these optics. Fortunately, owing to the rapid development of electronic devices and computer vision technology, fringe reflection technique (FRT) with advantages of simple system structure, high measurement accuracy and large dynamic range is becoming a powerful tool for specular free-form surface testing. In order to obtain absolute surface shape distributions of test objects, two or more cameras are often required in the conventional FRT which makes the system structure more complex and the measurement cost much higher. Furthermore, high precision synchronization between each camera is also a troublesome issue. To overcome the aforementioned drawback, a virtual-stereo FRT for specular free-form surface testing is put forward in this paper. It is able to achieve absolute profiles with the help of only one single biprism and a camera meanwhile avoiding the problems of stereo FRT based on binocular or multi-ocular cameras. Preliminary experimental results demonstrate the feasibility of the proposed technique.

  7. Surface energy loss processes in XPS studied by absolute reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Nagatomi, T.; Goto, K.

    2010-01-01

    The results of the investigation of the inelastic interaction of 300-3000 eV electrons with the Ni and Au surfaces by the analysis of absolute reflection electron energy loss spectroscopy (REELS) spectra were described. The present analysis enables the inelastic mean free path (IMFP), surface excitation parameter (SEP) and differential SEP (DSEP) to be obtained simultaneously from an absolute REELS spectrum. The obtained IMFPs for Ni and Au showed a good agreement with those calculated using the TPP-2M predictive equation. The present SEPs determined for Ni and Au were fitted to the Chen's formula describing the dependence of the SEP on the electron energy, and material parameters for Ni and Au in Chen's formula were proposed. The present DESPs were compared with the theoretical results, and a reasonable agreement between the experimentally determined DSEPs and theoretical results was confirmed. The MC modeling of calculating the REELS spectrum, in which energy loss processes due to surface excitations are taken into account, was also described. The IMFP, SEP and DSEP determined by the present absolute REELS analysis were employed to describe energy loss processes by inelastic scattering in the proposed MC simulation. The simulated REELS spectra were found to be in a good agreement with the experimental spectra for both Ni and Au.

  8. Evaluation of surface quality by Fractal Dimension and Volume ...

    African Journals Online (AJOL)

    Experimental and simulation results have enabled to show than the large diameter ball under low loads and medium feed speeds, favors the elimination of peaks and reduction of fractal dimension whence quality improvement of surface. Keywords: burnishing, volume parameters, fractal dimension, experimental designs ...

  9. Effect of surface treatment of tailings on effluent quality

    International Nuclear Information System (INIS)

    Murray, D.R.

    1980-01-01

    Successful reclamation treatment, in preparation for long range abandonment of mining wastes, involves both surface treatment and water quality control containment of waste solids and liquid contaminants. This paper describes use of lysimeters containing 125 tonnes of tailings to determine the impact of gravel, sawdust, and vegetation as surface treatments on the quality and quantity of effluent produced from sulphide-containing uranium mill tailings. Over a five-year period these treatments were observed and compared with bare tailings where no surface addition was made. The treatments did not alter the effluent quality to a level acceptable to regulatory requirements. Surface treatments did not appear to affect the leaching of Ra-226, NH 4 and NO 3 . The concentration of Fe, SO 4 , Cu, Pb, and Al increased with the rise of acidity as the pH changed from pH 9.5 to pH 2 in four and one-half years. However the rate and extent of changes of some of these parameters vary with the treatment. The experimental results for the observed trends are presented with limited explanation. Original design problems and unexpected delays in tailing reactions have made firm conclusions impossible at this stage. These data, however, provide a base for further investigation and development of explanations and firm conclusions, as to the role of surface treatment in long-term waste abandonment

  10. Characterization of the Vajont landslide (North-Eastern Italy) by means of reflection and surface wave seismics

    Science.gov (United States)

    Petronio, Lorenzo; Boaga, Jacopo; Cassiani, Giorgio

    2016-05-01

    The mechanisms of the disastrous Vajont rockslide (North-Eastern Italy, October 9, 1963) have been studied in great detail over the past five decades. Nevertheless, the reconstruction of the rockslide dynamics still presents several uncertainties, including those related to the accurate estimation of the actual landslide mass. This work presents the results of a geophysical characterization of the Vajont landslide body in terms of material properties and buried geometry. Both aspects add new information to the existing dataset and will help a better understanding of the rockslide failure mechanisms and dynamics. In addition, some general considerations concerning the intricacies of landslide characterization can be drawn, with due attention to potential pitfalls. The employed techniques are: (i) high resolution P-wave reflection, (ii) high resolution SH-wave reflection, (iii) controlled source surface wave analysis. We adopted as a seismic source a vibrator both for P waves and SH waves, using vertical and horizontal geophones respectively. For the surface wave seismic survey we used a heavy drop-weight source and low frequency receivers. Despite the high noise level caused by the fractured conditions of the large rock body, a common situation in landslide studies, we managed to achieve a satisfying imaging quality of the landslide structure thanks to the large number of active channels, the short receiver interval and the test of appropriate seismic sources. The joint use of different seismic techniques help focus the investigation on the rock mass mechanical properties. Results are in good agreement with the available borehole data, the geological sections and the mechanical properties of the rockmass estimated by other studies. In general the proposed approach is likely to be applicable successfully to similar situations where scattering and other noise sources are a typical bottleneck to geophysical data acquisition on landslide bodies.

  11. Bio-inspired, subwavelength surface structures to control reflectivity, transmission, and scattering in the infrared

    Science.gov (United States)

    Lora Gonzalez, Federico

    Controlling the reflection of visible and infrared (IR) light at interfaces is extremely important to increase the power efficiency and performance of optics, electro-optical and (thermo)photovoltaic systems. The eye of the moth has evolved subwavelength protuberances that increase light transmission into the eye tissue and prevent reflection. The subwavelength protuberances effectively grade the refractive index from that of air (n=1) to that of the tissue (n=1.4), making the interface gradual, suppressing reflection. In theory, the moth-eye (ME) structures can be implemented with any material platform to achieve an antireflectance effect by scaling the pitch and size of protuberances for the wavelength range of interest. In this work, a bio-inspired, scalable and substrate-independent surface modification protocol was developed to realize broadband antireflective structures based on the moth-eye principle. Quasi-ordered ME arrays were fabricated in IR relevant materials using a colloidal lithography method to achieve highly efficient, omni-directional transmission of mid and far infrared (IR) radiation. The effect of structure height and aspect ratio on transmittance and scattering is explored, with discussion on experimental techniques and effective medium theory (EMT). The highest aspect ratio structures (AR = 9.4) achieved peak single-side transmittance of 98%, with >85% transmission for lambda = 7--30 microns. A detailed photon balance constructed by transmission, forward scattering, specular reflection and diffuse reflection measurements to quantify optical losses due to near-field effects will be discussed. In addition, angle-dependent transmission measurements showed that moth-eye structures provide superior antireflective properties compared to unstructured interfaces over a wide angular range (0--60° incidence). Finally, subwavelength ME structures are incorporated on a Si substrate to enhance the absorption of near infrared (NIR) light in PtSi films to

  12. Detecting moisture status of pecan orchards and the potential of remotely-sensed surface reflectance data

    Science.gov (United States)

    Othman, Yahia Abdelrahman

    Demand for New Mexico's limited water resources coupled with periodic drought has increased the need to schedule irrigation of pecan orchards based on tree water status. The overall goal of this research was to develop advanced tree water status sensing techniques to optimize irrigation scheduling of pecan orchards. To achieve this goal, I conducted three studies in the La Mancha and Leyendecker orchards, both mature pecan orchards located in the Mesilla Valley, New Mexico. In the first study, I screened leaf-level physiological changes that occurred during cyclic irrigation to determine parameters that best represented changes in plant moisture status. Then, I linked plant physiological changes to remotely-sensed surface reflectance data derived from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+). In the second study, I assessed the impact of water deficits that developed during the flood irrigation dry-down cycles on photosynthesis (A) and gas exchange and established preliminary water deficit thresholds of midday stem water potential (Psi smd) critical to A and gas exchange of pecans. In a third study, I investigated whether hyperspectral data obtained from a handheld spectroradiometer and multispectral remotely-sensed data derived from Landsat 7 ETM+ and Landsat 8 Operational Land Imager (OLI) could detect moisture status in pecans during cyclic flood irrigations. I conducted the first study simultaneously in both orchards. Leaf-level physiological responses and remotely-sensed surface reflectance data were collected from trees that were either well watered or in water deficit. Midday stem water potential was the best leaf-level physiological response to detect moisture status in pecans. Multiple linear regression between Psismd and vegetation indices revealed a significant relationship (R 2 = 0.54) in both orchards. Accordingly, I concluded that remotely-sensed multispectral data form Landsat TMETM+ holds promise for detecting the moisture

  13. Transient reflection and transmission of E polarized electromagnetic waves at boundary surface between air and moving isotropic plasma

    International Nuclear Information System (INIS)

    Saito, Yukimasa

    1977-01-01

    The transient reflection and transmission waves of E polarized electromagnetic waves coming into the boundary surface between air and moving isotropic plasma were theoretically investigated. By using the Laplace transformation in the moving system, the formulae of Lorentz and inverse Lorentz transformations concerning electromagnetic field were transformed, thus the transient reflection and transmission waves were obtained. These waves were normalized with the angular frequency of the incident waves, and the variation of the wave form was obtained. Examples of the numerical calculation of reflected waves are shown for the plasma moving in parallel to the boundary surface. (Kato, T.)

  14. Improved analytical formulas for x-ray and neutron reflection from surface films

    International Nuclear Information System (INIS)

    Zhou, X.; Chen, S.; Felcher, G.P.

    1992-01-01

    A general and exact expression for x-ray and neutron reflectance and transmittance is given in terms of an integral of the real-space scattering-length-density profile fluctuation of the film, with respect to an arbitrary constant reference density level, over the wave function inside the film. Various special cases and approximations are then derived from this exact form by suitable approximations of the wave function. In particular, two practical approximate formulas are derived which are improvement over the corresponding distorted-wave Born approximations. One is for an arbitrary film deposited on a known substrate and the other for a free liquid surface. Numerical results are used to illustrate the accuracy of these formulas

  15. Modified polarized geometrical attenuation model for bidirectional reflection distribution function based on random surface microfacet theory.

    Science.gov (United States)

    Liu, Hong; Zhu, Jingping; Wang, Kai

    2015-08-24

    The geometrical attenuation model given by Blinn was widely used in the geometrical optics bidirectional reflectance distribution function (BRDF) models. Blinn's geometrical attenuation model based on symmetrical V-groove assumption and ray scalar theory causes obvious inaccuracies in BRDF curves and negatives the effects of polarization. Aiming at these questions, a modified polarized geometrical attenuation model based on random surface microfacet theory is presented by combining of masking and shadowing effects and polarized effect. The p-polarized, s-polarized and unpolarized geometrical attenuation functions are given in their separate expressions and are validated with experimental data of two samples. It shows that the modified polarized geometrical attenuation function reaches better physical rationality, improves the precision of BRDF model, and widens the applications for different polarization.

  16. Raman scattering and attenuated-total-reflection studies of surface-plasmon polaritons

    International Nuclear Information System (INIS)

    Kurosawa, K.; Pierce, R.M.; Ushioda, S.; Hemminger, J.C.

    1986-01-01

    We have made in situ measurements of attenuated total reflection (ATR) and Raman scattering from a layered structure consisting of a glass prism, a thin silver film, an MgF 2 spacer, and a liquid mixture whose refractive index is matched to that of MgF 2 . When the incident angle of the laser beam coincides with the ATR angle, the surface-plasmon polariton (SPP) of the silver film is excited resonantly and the Raman scattering intensity of the liquid shows a maximum. The same effect is observed at the frequency of the Stokes scattered light. By measuring the decrease of the Raman scattering intensity of the liquid with increase of the thickness of the MgF 2 spacer layer, we have determined the decay length (l/sub d/) of the SPP field into the liquid. The measured value of l/sub d/ = 1539 A agrees with the calculated value, 1534 A

  17. Recent Developments in the X-Ray Reflectivity Analysis for Rough Surfaces and Interfaces of Multilayered Thin Film Materials

    Directory of Open Access Journals (Sweden)

    Yoshikazu Fujii

    2013-01-01

    Full Text Available X-ray reflectometry is a powerful tool for investigations on rough surface and interface structures of multilayered thin film materials. The X-ray reflectivity has been calculated based on the Parratt formalism, accounting for the effect of roughness by the theory of Nevot-Croce conventionally. However, in previous studies, the calculations of the X-ray reflectivity often show a strange effect where interference effects would increase at a rough surface. And estimated surface and interface roughnesses from the X-ray reflectivity measurements did not correspond to the TEM image observation results. The strange result had its origin in a used equation due to a serious mistake in which the Fresnel transmission coefficient in the reflectivity equation is increased at a rough interface because of a lack of consideration of diffuse scattering. In this review, a new accurate formalism that corrects this mistake is presented. The new accurate formalism derives an accurate analysis of the X-ray reflectivity from a multilayer surface of thin film materials, taking into account the effect of roughness-induced diffuse scattering. The calculated reflectivity by this accurate reflectivity equation should enable the structure of buried interfaces to be analyzed more accurately.

  18. [Studies on a sequential injection renewable surface reflectance spectrophotometric system using a microchip flow cell].

    Science.gov (United States)

    Wang, Jian-ya; Fang, Zhao-lun

    2002-02-01

    A microchip flow cell was developed for flow injection renewable surface assay by reflectance spectrophotometry. The flow cell was coupled to a sequential injection system and optical fiber photometric detection system. The flow cell featured a three-layer structure. The flow channel was cut into a silicone rubber membrance which formed the middle layer, and a porous filter was inlayed across a widened section of the channel to trap microbeads introduced into the flow cell. The area of the detection window of the flow cell was approximately 3.6 mm2, the volume of the bead trapped in the flow cell was 2.2 microL, the depth of the bead layer was 600 microns. A multistrand bifurcated optical fiber was coupled with incident light, detector and flow cell. The chromogenic reaction of Cr(VI) with 1,5-diphenylcarbohydrazide (DPC) which was adsorbed on trapped Polysorb C-18 beads was used as a model reaction to optimize the flow cell design and the experimental system. The reflectance of the renewable reaction surface was monitored at 540 nm. With 100 microL sample loaded and 1.0 mL.min-1 carrier flow rate, the linear response range was 0-0.6 microgram.mL-1 Cr(VI). A detection limit (3 sigma) of 6 ng.mL-1, precision of 1.5% RSD(n = 11), and a throughput of 64 samples per hour were achieved. Considerations in system and flow cell design, the influence of depth of the bead layer, weight of beads used, and the flow rates of carrier stream on the performance were discussed.

  19. Responses of Surface Ozone Air Quality to Anthropogenic Nitrogen Deposition

    Science.gov (United States)

    Zhang, L.; Zhao, Y.; Tai, A. P. K.; Chen, Y.; Pan, Y.

    2017-12-01

    Human activities have substantially increased atmospheric deposition of reactive nitrogen to the Earth's surface, inducing unintentional effects on ecosystems with complex environmental and climate consequences. One consequence remaining unexplored is how surface air quality might respond to the enhanced nitrogen deposition through surface-atmosphere exchange. We combine a chemical transport model (GEOS-Chem) and a global land model (Community Land Model) to address this issue with a focus on ozone pollution in the Northern Hemisphere. We consider three processes that are important for surface ozone and can be perturbed by addition of atmospheric deposited nitrogen: emissions of biogenic volatile organic compounds (VOCs), ozone dry deposition, and soil nitrogen oxide (NOx) emissions. We find that present-day anthropogenic nitrogen deposition (65 Tg N a-1 to the land), through enhancing plant growth (represented as increases in vegetation leaf area index (LAI) in the model), could increase surface ozone from increased biogenic VOC emissions, but could also decrease ozone due to higher ozone dry deposition velocities. Meanwhile, deposited anthropogenic nitrogen to soil enhances soil NOx emissions. The overall effect on summer mean surface ozone concentrations show general increases over the globe (up to 1.5-2.3 ppbv over the western US and South Asia), except for some regions with high anthropogenic NOx emissions (0.5-1.0 ppbv decreases over the eastern US, Western Europe, and North China). We compare the surface ozone changes with those driven by the past 20-year climate and historical land use changes. We find that the impacts from anthropogenic nitrogen deposition can be comparable to the climate and land use driven surface ozone changes at regional scales, and partly offset the surface ozone reductions due to land use changes reported in previous studies. Our study emphasizes the complexity of biosphere-atmosphere interactions, which can have important

  20. Developing a composite weighted quality metric to reflect the total benefit conferred by a health plan.

    Science.gov (United States)

    Taskler, Glen B; Braithwaite, R Scott

    2015-03-01

    To improve individual health quality measures, which are associated with varying degrees of health benefit, and composite quality metrics, which weight individual measures identically. We developed a health-weighted composite quality measure reflecting the total health benefit conferred by a health plan annually, using preventive care as a test case. Using national disease prevalence, we simulated a hypothetical insurance panel of individuals aged 25 to 84 years. For each individual, we estimated the gain in life expectancy associated with 1 year of health system exposure to encourage adherence to major preventive care guidelines, controlling for patient characteristics (age, race, gender, comorbidity) and variation in individual adherence rates. This personalized gain in life expectancy was used to proxy for the amount of health benefit conferred by a health plan annually to its members, and formed weights in our health-weighted composite quality measure. We aggregated health benefits across the health insurance membership panel to analyze total health system performance. Our composite quality metric gave the highest weights to health plans that succeeded in implementing tobacco cessation and weight loss. One year of compliance with these goals was associated with 2 to 10 times as much health benefit as compliance with easier-to-follow preventive care services, such as mammography, aspirin, and antihypertensives. For example, for women aged 55 to 64 years, successful interventions to encourage weight loss were associated with 2.1 times the health benefit of blood pressure reduction and 3.9 times the health benefit of increasing adherence with screening mammography. A single health-weighted quality metric may inform measurement of total health system performance.

  1. A Harmonized Landsat-Sentinel-2 Surface Reflectance product: a resource for Agricultural Monitoring

    Science.gov (United States)

    Masek, J. G.; Claverie, M.; Ju, J.; Vermote, E.; Justice, C. O.

    2015-12-01

    The combination of Landsat and Sentinel-2 data offers a unique opportunity to observe globally the land every 2-3 days at medium (reflectance data from Landsat and Sentinel-2 missions and to deliver them to the community in a combined, seamless form. The HLS will be beneficial for global agricultural monitoring applications that require medium spatial resolution and weekly or more frequent observations. In particular, the provided opportunity to track crop phenology at the scale of individual fields will support detailed mapping of crop type and type-specific vegetation conditions. To create a compatible set of radiometric measurements, the HLS product relies on rigorous pre- and post-launch cross-calibration (Landsat-8 OLI and Sentinel-2 MSI) activities. The processing chain includes the following components: atmospheric correction, cloud/shadow masking, nadir BRDF-adjustment, spectral-adjustment, regridding, and temporal composite. The atmospheric correction and cloud masking is based on the OLI atmospheric correction developed at NASA-GSFC and has been adapted to the MSI data. The BRDF-adjustment is based on a disaggregation technique using MODIS-based BRDF coefficients. The technique has been evaluated using the multi-angular acquisition from the SPOT 4 and 5 (Take5) experiments. The spectral-adjustment relies on a linear regression that has been calibrated and evaluated using synthetic data and surface reflectance processed from a large number of hyperspectral EO-1 Hyperion scenes. Finally, significant effort is placed on product validation and evaluation. The delivered data set will include surface reflectance products at different levels: Using the native gridding, i.e. UTM, 30m for Landsat-8, and UTM, 10-20m for Sentinel-2 Using a common global gridding (Sinusoidal, 30m) Temporal composite (Sinusoidal, 30m, 5-day) During the first year of operation of Sentinel-2A, the HLS will be prototyped over a selection of 30 sites that includes some of the JECAM sites

  2. Seasonal lake surface water temperature trends reflected by heterocyst glycolipid-based molecular thermometers

    Science.gov (United States)

    Bauersachs, T.; Rochelmeier, J.; Schwark, L.

    2015-06-01

    preserved in the sediment record of Lake Schreventeich reflect summer surface water temperatures. As N2-fixing heterocystous cyanobacteria are widespread in present-day freshwater and brackish environments, we conclude that the distribution of HGs in sediments may allow for the reconstruction of surface water temperatures of modern and potentially ancient lacustrine settings.

  3. Developing a more useful surface quality metric for laser optics

    Science.gov (United States)

    Turchette, Quentin; Turner, Trey

    2011-02-01

    Light scatter due to surface defects on laser resonator optics produces losses which lower system efficiency and output power. The traditional methodology for surface quality inspection involves visual comparison of a component to scratch and dig (SAD) standards under controlled lighting and viewing conditions. Unfortunately, this process is subjective and operator dependent. Also, there is no clear correlation between inspection results and the actual performance impact of the optic in a laser resonator. As a result, laser manufacturers often overspecify surface quality in order to ensure that optics will not degrade laser performance due to scatter. This can drive up component costs and lengthen lead times. Alternatively, an objective test system for measuring optical scatter from defects can be constructed with a microscope, calibrated lighting, a CCD detector and image processing software. This approach is quantitative, highly repeatable and totally operator independent. Furthermore, it is flexible, allowing the user to set threshold levels as to what will or will not constitute a defect. This paper details how this automated, quantitative type of surface quality measurement can be constructed, and shows how its results correlate against conventional loss measurement techniques such as cavity ringdown times.

  4. An analytical and numerical study of the nonlinear reflection at a stress-free surface

    Energy Technology Data Exchange (ETDEWEB)

    Romer, Anne, E-mail: anne.romer@gmx.net; Kim, Jin-Yeon, E-mail: anne.romer@gmx.net [School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Jacobs, Laurence J. [School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA and G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2015-03-31

    Implementation of the ultrasonic second harmonic generation has typically been restricted to simple setups such as through-transmission or Rayleigh surface waves. Recent research has evaluated the second harmonic waves generation in P- and SV- waves reflected from a stress-free surface to enable the single-sided interrogation of a specimen. This research considers the second harmonic generation in an aluminum specimen, which is analytically evaluated using an approach based on a perturbation method. Here, the model is chosen to mimic an experimental setup where the longitudinal wave is generated at oblique angle using a wedge transducer. Due to the mode conversion at the interface of the wedge and the specimen, it is necessary to evaluate longitudinal and shear waves, determining all second harmonic waves generated in the bulk and at the stress-free boundary. The theoretically developed model is then implemented in a commercial finite element code, COMSOL, using increasing fundamental wave amplitudes for different values of third order elastic constants. The results of this computational model verify the analytical approach and the proposed measurement setup, taking into account assumptions and approximations of the solution procedure. Furthermore, the computational model is used to draw important conclusions relevant to the experimental setup, including the need to avoid interaction with diffracted waves.

  5. Spontaneous acoustic emission of a corrugated shock wave in the presence of a reflecting surface

    International Nuclear Information System (INIS)

    Wouchuk, J.G.; Lopez Cavada, J.

    2004-01-01

    An analytic model to study perturbation evolution in the space between a corrugated shock and a piston surface is presented. The conditions for stable oscillation patterns are obtained by looking at the poles of the exact Laplace transform. It is seen that besides the standard D'yakov-Kontorovich (DK) mode of oscillation, the shock surface can exhibit an additional finite set of discrete frequencies, due to the interaction with the piston which reflects sound waves from behind. The additional eigenmodes are excited when the shock is launched at t=0 + . The first eigenmode (the DK mode) is always present, if the Hugoniot curve has the correct slope in the V-p plane. However, the additional frequencies could be excited for strong enough shocks. The predictions of the model are verified for particular cases by studying a van der Waals gas, as in the work of Bates and Montgomery [Phys. Fluids 11, 462 (1999); Phys. Rev. Lett. 84, 1180 (2000)]. Only acoustic emission modes are considered

  6. Quality Control of Valerianae Radix by Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopy.

    Science.gov (United States)

    Nikzad-Langerodi, Ramin; Arth, Katharina; Klatte-Asselmeyer, Valerie; Bressler, Sabine; Saukel, Johannes; Reznicek, Gottfried; Dobeš, Christoph

    2018-04-01

    (Acetoxy-)valerenic acid and total essential oil content are important quality attributes of pharmacy grade valerian root (Valerianae radix). Traditional analysis of these quantities is time-consuming and necessitates (harmful) solvents. Here we investigated an application of attenuated total reflection Fourier transform infrared spectroscopy for extractionless analysis of these quality attributes on a representative sample comprising 260 wild-crafted individuals covering the Central European taxonomic diversity of the Valeriana officinalis L. s. l. species aggregate with its three major ploidy cytotypes (i.e., di-, tetra- and octoploid). Calibration models were built by orthogonal partial least squares regression for quantitative analysis of (acetoxy-)valerenic acid and total essential oil content. For the latter, we propose a simplistic protocol involving apolar extraction followed by gas chromatography as a reference method for multivariate calibration in order to handle the analysis of samples taken from individual plants. We found good predictive ability of chemometric models for quantification of valerenic acid, acetoxyvalerenic acid, total sesquiterpenoid acid, and essential oil content with a root mean squared error of cross-validation of 0.064, 0.043, and 0.09 and root mean squared error of prediction of 0.066, 0.057, and 0.09 (% content), respectively. Orthogonal partial least squares discriminant analysis revealed good discriminability between the most productive phenotype (i.e., the octoploid cytotype) in terms of sesquiterpenoid acids, and the less productive ones (i.e., di- and tetraploid). All in all, our results demonstrate the application of attenuated total reflection Fourier transform infrared spectroscopy for rapid, extractionless estimation of the most important quality attributes of valerian root and minimally invasive identification of the most productive phenotype in terms of sesquiterpenoid acids. Georg Thieme Verlag KG Stuttgart · New

  7. Automated sulcal depth measurement on cortical surface reflecting geometrical properties of sulci.

    Directory of Open Access Journals (Sweden)

    Hyuk Jin Yun

    Full Text Available Sulcal depth that is one of the quantitative measures of cerebral cortex has been widely used as an important marker for brain morphological studies. Several studies have employed Euclidean (EUD or geodesic (GED algorithms to measure sulcal depth, which have limitations that ignore sulcal geometry in highly convoluted regions and result in under or overestimated depth. In this study, we proposed an automated measurement for sulcal depth on cortical surface reflecting geometrical properties of sulci, which named the adaptive distance transform (ADT. We first defined the volume region of cerebrospinal fluid between the 3D convex hull and the cortical surface, and constructed local coordinates for that restricted region. Dijkstra's algorithm was then used to compute the shortest paths from the convex hull to the vertices of the cortical surface based on the local coordinates, which may be the most proper approach for defining sulcal depth. We applied our algorithm to both a clinical dataset including patients with mild Alzheimer's disease (AD and 25 normal controls and a simulated dataset whose shape was similar to a single sulcus. The mean sulcal depth in the mild AD group was significantly lower than controls (p = 0.007, normal [mean±SD]: 7.29±0.23 mm, AD: 7.11±0.29 and the area under the receiver operating characteristic curve was relatively high, showing the value of 0.818. Results from clinical dataset that were consistent with former studies using EUD or GED demonstrated that ADT was sensitive to cortical atrophy. The robustness against inter-individual variability of ADT was highlighted through simulation dataset. ADT showed a low and constant normalized difference between the depth of the simulated data and the calculated depth, whereas EUD and GED had high and variable differences. We suggest that ADT is more robust than EUD or GED and might be a useful alternative algorithm for measuring sulcal depth.

  8. Deriving surface soil moisture from reflected GNSS signal observations from a grassland site in southwestern France

    Science.gov (United States)

    Zhang, Sibo; Calvet, Jean-Christophe; Darrozes, José; Roussel, Nicolas; Frappart, Frédéric; Bouhours, Gilles

    2018-03-01

    This work assesses the estimation of surface volumetric soil moisture (VSM) using the global navigation satellite system interferometric reflectometry (GNSS-IR) technique. Year-round observations were acquired from a grassland site in southwestern France using an antenna consecutively placed at two contrasting heights above the ground surface (3.3 and 29.4 m). The VSM retrievals are compared with two independent reference datasets: in situ observations of soil moisture, and numerical simulations of soil moisture and vegetation biomass from the ISBA (Interactions between Soil, Biosphere and Atmosphere) land surface model. Scaled VSM estimates can be retrieved throughout the year removing vegetation effects by the separation of growth and senescence periods and by the filtering of the GNSS-IR observations that are most affected by vegetation. Antenna height has no significant impact on the quality of VSM estimates. Comparisons between the VSM GNSS-IR retrievals and the in situ VSM observations at a depth of 5 cm show good agreement (R2 = 0.86 and RMSE = 0.04 m3 m-3). It is shown that the signal is sensitive to the grass litter water content and that this effect triggers differences between VSM retrievals and in situ VSM observations at depths of 1 and 5 cm, especially during light rainfall events.

  9. Deriving surface soil moisture from reflected GNSS signal observations from a grassland site in southwestern France

    Directory of Open Access Journals (Sweden)

    S. Zhang

    2018-03-01

    Full Text Available This work assesses the estimation of surface volumetric soil moisture (VSM using the global navigation satellite system interferometric reflectometry (GNSS-IR technique. Year-round observations were acquired from a grassland site in southwestern France using an antenna consecutively placed at two contrasting heights above the ground surface (3.3 and 29.4 m. The VSM retrievals are compared with two independent reference datasets: in situ observations of soil moisture, and numerical simulations of soil moisture and vegetation biomass from the ISBA (Interactions between Soil, Biosphere and Atmosphere land surface model. Scaled VSM estimates can be retrieved throughout the year removing vegetation effects by the separation of growth and senescence periods and by the filtering of the GNSS-IR observations that are most affected by vegetation. Antenna height has no significant impact on the quality of VSM estimates. Comparisons between the VSM GNSS-IR retrievals and the in situ VSM observations at a depth of 5 cm show good agreement (R2 =  0.86 and RMSE  =  0.04 m3 m−3. It is shown that the signal is sensitive to the grass litter water content and that this effect triggers differences between VSM retrievals and in situ VSM observations at depths of 1 and 5 cm, especially during light rainfall events.

  10. The laboratory investigation of surface envelope solitons: reflection from a vertical wall and collisions of solitons

    Science.gov (United States)

    Slunyaev, Alexey; Klein, Marco; Clauss, Günther F.

    2016-04-01

    Envelope soliton solutions are key elements governing the nonlinear wave dynamics within a simplified theory for unidirectional weakly modulated weakly nonlinear wave groups on the water surface. Within integrable models the solitons preserve their structure in collisions with other waves; they do not disperse and can carry energy infinitively long. Steep and short soliton-like wave groups have been shown to exist in laboratory tests [1] and, even earlier, in numerical simulations [2, 3]. Thus, long-living wave groups may play important role in the dynamics of intense sea waves and wave-structure interactions. The solitary wave groups may change the wave statistics and can be taken into account when developing approaches for the deterministic forecasting of dangerous waves, including so-called rogue waves. An experimental campaign has been conducted in the wave basin of the Technical University of Berlin on simulations of intense solitary wave groups. The first successful experimental observation of intense envelope solitons took place in this facility [1]. The new experiments aimed at following main goals: 1) to reproduce intense envelope solitons with different carrier wave lengths; 2) to estimate the rate of envelope soliton dissipation; 3) to consider the reflection of envelope solitons on a vertical wall; 4) to consider head-on collisions of envelope solitons, and 5) to consider overtaking interactions of envelope solitons. Up to 9 wave gauges were used in each experimental run, which enabled registration of the surface movement at different distances from the wavemaker, at different locations across the wave flume and near the wall. Besides surface displacements, the group envelope shapes were directly recorded, with use of phase shifts applied to the modulated waves generated by the wavemaker. [1] A. Slunyaev, G.F. Clauss, M. Klein, M. Onorato, Simulations and experiments of short intense envelope solitons of surface water waves. Phys. Fluids 25, 067105

  11. An Operational Scheme for Deriving Standardised Surface Reflectance from Landsat TM/ETM+ and SPOT HRG Imagery for Eastern Australia

    Directory of Open Access Journals (Sweden)

    Neil Flood

    2013-01-01

    Full Text Available Operational monitoring of vegetation and land surface change over large areas can make good use of satellite sensors that measure radiance reflected from the Earth’s surface. Monitoring programs use multiple images for complete spatial coverage over time. Accurate retrievals of vegetation cover and vegetation change estimates can be hampered by variation, in both space and time, in the measured radiance, caused by atmospheric conditions, topography, sensor location, and sun elevation. In order to obtain estimates of cover that are comparable between images, and to retrieve accurate estimates of change, these sources of variation must be removed. In this paper we present a preprocessing scheme for minimising atmospheric, topographic and bi-directional reflectance effects on Landsat-5 TM, Landsat-7 ETM+ and SPOT-5 HRG imagery. The approach involves atmospheric correction to compute surface-leaving radiance, and bi-directional reflectance modelling to remove the effects of topography and angular variation in reflectance. The bi-directional reflectance model has been parameterised for eastern Australia, but the general approach is more widely applicable. The result is surface reflectance standardised to a fixed viewing and illumination geometry. The method can be applied to the entire record for these instruments, without intervention, which is of increasing importance with the increased availability of long term image archives. Validation shows that the corrections improve the estimation of reflectance at any given angular configuration, thus allowing the removal from the reflectance signal of much variation due to factors independent of the land surface. The method has been used to process over 45,000 Landsat-5 TM and Landsat-7 ETM+ scenes and 2,500 SPOT-5 scenes, over eastern Australia, and is now in use in operational monitoring programs.

  12. Ultraviolet (UV)-reflective paint with ultraviolet germicidal irradiation (UVGI) improves decontamination of nosocomial bacteria on hospital room surfaces.

    Science.gov (United States)

    Jelden, Katelyn C; Gibbs, Shawn G; Smith, Philip W; Hewlett, Angela L; Iwen, Peter C; Schmid, Kendra K; Lowe, John J

    2017-06-01

    An ultraviolet germicidal irradiation (UVGI) generator (the TORCH, ClorDiSys Solutions, Inc.) was used to compare the disinfection of surface coupons (plastic from a bedrail, stainless steel, and chrome-plated light switch cover) in a hospital room with walls coated with ultraviolet (UV)-reflective paint (Lumacept) or standard paint. Each surface coupon was inoculated with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus faecalis (VRE), placed at 6 different sites within a hospital room coated with UV-reflective paint or standard paint, and treated by 10 min UVC exposure (UVC dose of 0-688 mJ/cm 2 between sites with standard paint and 0-553 mJ/cm 2 with UV-reflective paint) in 8 total trials. Aggregated MRSA concentrations on plastic bedrail surface coupons were reduced on average by 3.0 log 10 (1.8 log 10 Geometric Standard Deviation [GSD]) with standard paint and 4.3 log 10 (1.3 log 10 GSD) with UV-reflective paint (p = 0.0005) with no significant reduction differences between paints on stainless steel and chrome. Average VRE concentrations were reduced by ≥4.9 log 10 (surface types with UV-reflective paint and ≤4.1 log 10 (hospital bed from the UVGI generator, MRSA concentrations on average were reduced by 1.3 log 10 (1.7 log 10 GSD) with standard paint and 4.7 log 10 (1.3 log 10 GSD) with UV-reflective paint (p hospital room walls with UV-reflective paint enhanced UVGI disinfection of nosocomial bacteria on various surfaces compared to standard paint, particularly at a surface placement site indirectly exposed to UVC light.

  13. A sea surface reflectance model for (AATSR, and application to aerosol retrievals

    Directory of Open Access Journals (Sweden)

    A. M. Sayer

    2010-07-01

    Full Text Available A model of the sea surface bidirectional reflectance distribution function (BRDF is presented for the visible and near-IR channels (over the spectral range 550 nm to 1.6 μm of the dual-viewing Along-Track Scanning Radiometers (ATSRs. The intended application is as part of the Oxford-RAL Aerosols and Clouds (ORAC retrieval scheme. The model accounts for contributions to the observed reflectance from whitecaps, sun-glint and underlight. Uncertainties in the parametrisations used in the BRDF model are propagated through into the forward model and retrieved state. The new BRDF model offers improved coverage over previous methods, as retrievals are possible into the sun-glint region, through the ATSR dual-viewing system. The new model has been applied in the ORAC aerosol retrieval algorithm to process Advanced ATSR (AATSR data from September 2004 over the south-eastern Pacific. The assumed error budget is shown to be generally appropriate, meaning the retrieved states are consistent with the measurements and a priori assumptions. The resulting field of aerosol optical depth (AOD is compared with colocated MODIS-Terra observations, AERONET observations at Tahiti, and cruises over the oceanic region. MODIS and AATSR show similar spatial distributions of AOD, although MODIS reports values which are larger and more variable. It is suggested that assumptions in the MODIS aerosol retrieval algorithm may lead to a positive bias in MODIS AOD of order 0.01 at 550 nm over ocean regions where the wind speed is high.

  14. Impacts of dust aerosol and adjacency effects on the accuracy of Landsat 8 and RapidEye surface reflectances

    KAUST Repository

    Houborg, Rasmus; McCabe, Matthew

    2017-01-01

    The atmospheric correction of satellite data is challenging over desert agricultural systems, due to the relatively high aerosol optical thicknesses (τ550), bright soils, and a heterogeneous surface reflectance field. Indeed, the contribution of reflected radiation from adjacent pixels scattered into the field of view of a target pixel is considerable and can significantly affect the fidelity of retrieved reflectances. In this study, uncertainties and quantitative errors associated with the atmospheric correction of multi-spectral Landsat 8 and RapidEye data were characterized over a desert agricultural landscape in Saudi Arabia. Surface reflectances were retrieved using an implementation of the 6SV atmospheric correction code, and validated against field collected spectroradiometer measurements over desert, cultivated soil, and vegetated surface targets. A combination of satellite and Aerosol Robotic Network (AERONET) data were used to parameterize aerosol properties and atmospheric state parameters. With optimal specification of τ550 and aerosol optical properties and correction for adjacency effects, the relative Mean Absolute Deviation (MAD) for all bands combined was 5.4% for RapidEye and 6.8% for Landsat 8. However uncertainties associated with satellite-based τ550 retrievals were shown to introduce significant error into the reflectance estimates. With respect to deriving common vegetation indices from corrected reflectance data, the Normalized Difference Vegetation Index (NDVI) was associated with the smallest errors (3–8% MAD). Surface reflectance errors were highest for bands in the visible part of the spectrum, particularly the blue band (5–16%), while there was more consistency within the red-edge (~ 5%) and near-infrared (5–7%). Results were generally better constrained when a τ550-dependent aerosol model for desert dust particles, parameterized on the basis of nearby AERONET site data, was used in place of a generic rural or background

  15. Impacts of dust aerosol and adjacency effects on the accuracy of Landsat 8 and RapidEye surface reflectances

    KAUST Repository

    Houborg, Rasmus

    2017-03-29

    The atmospheric correction of satellite data is challenging over desert agricultural systems, due to the relatively high aerosol optical thicknesses (τ550), bright soils, and a heterogeneous surface reflectance field. Indeed, the contribution of reflected radiation from adjacent pixels scattered into the field of view of a target pixel is considerable and can significantly affect the fidelity of retrieved reflectances. In this study, uncertainties and quantitative errors associated with the atmospheric correction of multi-spectral Landsat 8 and RapidEye data were characterized over a desert agricultural landscape in Saudi Arabia. Surface reflectances were retrieved using an implementation of the 6SV atmospheric correction code, and validated against field collected spectroradiometer measurements over desert, cultivated soil, and vegetated surface targets. A combination of satellite and Aerosol Robotic Network (AERONET) data were used to parameterize aerosol properties and atmospheric state parameters. With optimal specification of τ550 and aerosol optical properties and correction for adjacency effects, the relative Mean Absolute Deviation (MAD) for all bands combined was 5.4% for RapidEye and 6.8% for Landsat 8. However uncertainties associated with satellite-based τ550 retrievals were shown to introduce significant error into the reflectance estimates. With respect to deriving common vegetation indices from corrected reflectance data, the Normalized Difference Vegetation Index (NDVI) was associated with the smallest errors (3–8% MAD). Surface reflectance errors were highest for bands in the visible part of the spectrum, particularly the blue band (5–16%), while there was more consistency within the red-edge (~ 5%) and near-infrared (5–7%). Results were generally better constrained when a τ550-dependent aerosol model for desert dust particles, parameterized on the basis of nearby AERONET site data, was used in place of a generic rural or background

  16. Chromatic X-ray magnifying method and apparatus by Bragg reflective planes on the surface of Abbe sphere

    Science.gov (United States)

    Thoe, Robert S.

    1991-01-01

    Method and apparatus for producing sharp, chromatic, magnified images of X-ray emitting objects, are provided. The apparatus, which constitutes an X-ray microscope or telescope, comprises a connected collection of Bragg reflecting planes, comprised of either a bent crystal or a synthetic multilayer structure, disposed on and adjacent to a locus determined by a spherical surface. The individual Bragg planes are spatially oriented to Bragg reflect radiation from the object location toward the image location. This is accomplished by making the Bragg planes spatially coincident with the surfaces of either a nested series of prolate ellipsoids of revolution, or a nested series of spheres. The spacing between the Bragg reflecting planes can be tailored to control the wavelengths and the amount of the X-radiation that is Bragg reflected to form the X-ray image.

  17. Updating Landsat time series of surface-reflectance composites and forest change products with new observations

    Science.gov (United States)

    Hermosilla, Txomin; Wulder, Michael A.; White, Joanne C.; Coops, Nicholas C.; Hobart, Geordie W.

    2017-12-01

    The use of time series satellite data allows for the temporally dense, systematic, transparent, and synoptic capture of land dynamics over time. Subsequent to the opening of the Landsat archive, several time series approaches for characterizing landscape change have been developed, often representing a particular analytical time window. The information richness and widespread utility of these time series data have created a need to maintain the currency of time series information via the addition of new data, as it becomes available. When an existing time series is temporally extended, it is critical that previously generated change information remains consistent, thereby not altering reported change statistics or science outcomes based on that change information. In this research, we investigate the impacts and implications of adding additional years to an existing 29-year annual Landsat time series for forest change. To do so, we undertook a spatially explicit comparison of the 29 overlapping years of a time series representing 1984-2012, with a time series representing 1984-2016. Surface reflectance values, and presence, year, and type of change were compared. We found that the addition of years to extend the time series had minimal effect on the annual surface reflectance composites, with slight band-specific differences (r ≥ 0.1) in the final years of the original time series being updated. The area of stand replacing disturbances and determination of change year are virtually unchanged for the overlapping period between the two time-series products. Over the overlapping temporal period (1984-2012), the total area of change differs by 0.53%, equating to an annual difference in change area of 0.019%. Overall, the spatial and temporal agreement of the changes detected by both time series was 96%. Further, our findings suggest that the entire pre-existing historic time series does not need to be re-processed during the update process. Critically, given the time

  18. Objective and Subjective Evaluation of Reflecting and Diffusing Surfaces in Auditoria

    Science.gov (United States)

    Cox, Trevor John

    Available from UMI in association with The British Library. Requires signed TDF. The performance of reflectors and diffusers used in auditoria have been evaluated both objectively and subjectively. Two accurate systems have been developed to measure the scattering from surfaces via the cross correlation function. These have been used to measure the scattering from plane panels, curved panels and quadratic residue diffusers (QRDs). The scattering measurements have been used to test theoretical prediction methods based on the Helmholtz-Kirchhoff integral equation. Accurate prediction methods were found for all surfaces tested. The limitations of the more approximate methods have been defined. The assumptions behind Schroeder's design of the QRD have been tested and the local reacting admittance assumption found to be valid over a wide frequency range. It was found that the QRD only produces uniform scattering at low frequencies. For an on-axis source the scattering from a curved panel was as good as from a QRD. For an oblique source the QRD produced much more uniform scattering than the curved panel. The subjective measurements evaluated the smallest perceivable change in the early sound field, the part most influenced by reflectors and diffusers. A natural sounding simulation of a concert hall field within an anechoic chamber was used. Standard objective parameters were reasonable values when compared to values found in real halls and subjective preference measurements. A difference limen was measured for early lateral energy fraction (.048 +/-.005); inter aural cross correlation (.075 +/-.008); clarity index (.67 +/-.13 dB); and centre time (8.6 +/- 1.6 ms). It was found that: (i) when changes are made to diffusers and reflectors, changes in spatial impression will usually be larger than those in clarity; and (ii) acousticians can gain most by paying attention to lateral sound in auditoria. It was also found that: (i) diffuse reflections in the early sound field

  19. Environmetric data interpretation to assess surface water quality

    International Nuclear Information System (INIS)

    Simeonova, P.; Papazova, P.; Lovchinov, V.

    2013-01-01

    Two multivariate statistical methods (Cluster analysis /CA/ and Principal components analysis /PCA/) were applied for model assessment of the water quality of Maritsa River and Tundja River on Bulgarian territory. The study used long-term monitoring data from many sampling sites characterized by various surface water quality indicators. The application of CA to the indicators results in formation of clusters showing the impact of biological, anthropogenic and eutrophication sources. For further assessment of the monitoring data, PCA was implemented, which identified, again, latent factors confirming, in principle, the clustering output. Their identification coincide correctly to the location of real pollution sources along the rivers catchments. The linkage of the sampling sites along the river flow by CA identified several special patterns separated by specific tracers levels. The apportionment models of the pollution determined the contribution of each one of identified pollution factors to the total concentration of each one of the water quality parameters. Thus, a better risk management of the surface water quality is achieved both on local and national level

  20. QUALITY INFLUENCE OF SURFACE ON AIRCRAFT TAKE-OFF

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available The article considers quality impact influence of surface on aircraft take-off. It considers the IL-114 takeoff with all the operating engines. The goal of this research is to conduct calculating experiment to determine quality influence of surface on alteration of IL-114 takeoff characteristics during operation. Researches were carried out using the system of mathematical modeling of a flight dynamics. The main part of the system is a unit for calculating increments of aerodynam- ic coefficients caused with changing of technical condition of the surface of the airframe (roughness, waviness, available protruding elements on the airframe surface, etc. and residual deformation of the wing, fuselage, vertical and horizontal tail, as well as the difference between the rods symmetrically operating engines. In order to compute loss of rod and an increase in engine fuel consumption due to engine operation time during operation, an integral factor of thrust loss and increase in fuel consumption coefficient were introduced. Research proved that the individual characteristics of the aircraft, due to loss of engine power and increase in drag do not affect the assigned level of flight safety. The plane has a considera- ble reserve as for unsafe takeoff speed and the full gradient of climb, that ensures safety of operation.

  1. Impact of indoor surface material on perceived air quality.

    Science.gov (United States)

    Senitkova, I

    2014-03-01

    The material combination impact on perceived indoor air quality for various surface interior materials is presented in this paper. The chemical analysis and sensory assessments identifies health adverse of indoor air pollutants (TVOCs). In this study, emissions and odors from different common indoor surface materials were investigated in glass test chamber under standardized conditions. Chemical measurements (TVOC concentration) and sensory assessments (odor intensity, air acceptability) were done after building materials exposure to standardized conditions. The results of the chemical and sensory assessment of individual materials and their combinations are compared and discussed within the paper. The using possibility of individual material surface sorption ability was investigated. The knowledge of targeted sorption effects can be used in the interior design phase. The results demonstrate the various sorption abilities of various indoor materials as well as the various sorption abilities of the same indoor material in various combinations. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Giant enhancement of reflectance due to the interplay between surface confined wave modes and nonlinear gain in dielectric media.

    Science.gov (United States)

    Kim, Sangbum; Kim, Kihong

    2017-12-11

    We study theoretically the interplay between the surface confined wave modes and the linear and nonlinear gain of the dielectric layer in the Otto configuration. The surface confined wave modes, such as surface plasmons or waveguide modes, are excited in the dielectric-metal bilayer by obliquely incident p waves. In the purely linear case, we find that the interplay between linear gain and surface confined wave modes can generate a large reflectance peak with its value much greater than 1. As the linear gain parameter increases, the peak appears at smaller incident angles, and the associated modes also change from surface plasmons to waveguide modes. When the nonlinear gain is turned on, the reflectance shows very strong multistability near the incident angles associated with surface confined wave modes. As the nonlinear gain parameter is varied, the reflectance curve undergoes complicated topological changes and sometimes displays separated closed curves. When the nonlinear gain parameter takes an optimally small value, a giant amplification of the reflectance by three orders of magnitude occurs near the incident angle associated with a waveguide mode. We also find that there exists a range of the incident angle where the wave is dissipated rather than amplified even in the presence of gain. We suggest that this can provide the basis for a possible new technology for thermal control in the subwavelength scale.

  3. Image potential effect on the specular reflection coefficient of alkali ions scattered from a nickel surface at low energy

    International Nuclear Information System (INIS)

    Zemih, R.; Boudjema, M.; Benazeth, C.; Boudouma, Y.; Chami, A.C.

    2002-01-01

    The resonant charge exchange in the incoming path of alkali ions scattered at low energy from a polycrystalline nickel surface is studied by using the image effect occurring at glancing incidence (2-10 deg. from the surface plane) and for specular reflection. The part of the experimental artefacts (geometrical factor, surface roughness ...) is extracted from the reflection coefficient of almost completely neutralised projectiles (He + or Ne + ) compared with the coefficient obtained from numerical simulations (TRIM and MARLOWE codes). The present model explains very well the lowering of the reflection coefficient measured at grazing incidence (below 4 deg.). Furthermore, the optimised values of the charge fraction in the incoming path and the image potential are in agreement with the theoretical calculations in the case of Na + /Ni at 4 keV

  4. Neutron Reflection Study of Surface Adsorption of Fc, Fab, and the Whole mAb.

    Science.gov (United States)

    Li, Zongyi; Li, Ruiheng; Smith, Charles; Pan, Fang; Campana, Mario; Webster, John R P; van der Walle, Christopher F; Uddin, Shahid; Bishop, Steve M; Narwal, Rojaramani; Warwicker, Jim; Lu, Jian Ren

    2017-07-12

    Characterizing the influence of fragment crystallization (Fc) and antigen-binding fragment (Fab) on monoclonal antibody (mAb) adsorption at the air/water interface is an important step to understanding liquid mAb drug product stability during manufacture, shipping, and storage. Here, neutron reflection is used to study the air/water adsorption of a mAb and its Fc and Fab fragments. By varying the isotopic contrast, the adsorbed amount, thickness, orientation, and immersion of the adsorbed layers could be determined unambiguously. While Fc adsorption reached saturation within the hour, its surface adsorbed amount showed little variation with bulk concentration. In contrast, Fab adsorption was slower and the adsorbed amount was concentration dependent. The much higher Fc adsorption, as compared to Fab, was linked to its lower surface charge. Time and concentration dependence of mAb adsorption was dominated by Fab behavior, although both Fab and Fc behaviors contributed to the amount of mAb adsorbed. Changing the pH from 5.5 to 8.8 did not much perturb the adsorbed amount of Fc, Fab, or mAb. However, a small decrease in adsorption was observed for the Fc over pH 8-8.8 and vice versa for the Fab and mAb, consistent with a dominant Fab behavior. As bulk concentration increased from 5 to 50 ppm, the thicknesses of the Fc layers were almost constant at 40 Å, while Fab and mAb layers increased from 45 to 50 Å. These results imply that the adsorbed mAb, Fc, and Fab all retained their globular structures and were oriented with their short axial lengths perpendicular to the interface.

  5. Using the Surface Reflectance MODIS Terra Product to Estimate Turbidity in Tampa Bay, Florida

    Directory of Open Access Journals (Sweden)

    Douglas L. Rickman

    2010-12-01

    Full Text Available Turbidity is a commonly-used index of the factors that determine light penetration in the water column. Consistent estimation of turbidity is crucial to design environmental and restoration management plans, to predict fate of possible pollutants, and to estimate sedimentary fluxes into the ocean. Traditional methods monitoring fixed geographical locations at fixed intervals may not be representative of the mean water turbidity in estuaries between intervals, and can be expensive and time consuming. Although remote sensing offers a good solution to this limitation, it is still not widely used due in part to required complex processing of imagery. There are satellite-derived products, including the Moderate Resolution Imaging Spectroradiometer (MODIS Terra surface reflectance daily product (MOD09GQ Band 1 (620–670 nm which are now routinely available at 250 m spatial resolution and corrected for atmospheric effect. This study shows this product to be useful to estimate turbidity in Tampa Bay, Florida, after rainfall events (R2 = 0.76, n = 34. Within Tampa Bay, Hillsborough Bay (HB and Old Tampa Bay (OTB presented higher turbidity compared to Middle Tampa Bay (MTB and Lower Tampa Bay (LTB.

  6. How Can Polarization States of Reflected Light from Snow Surfaces Inform Us on Surface Normals and Ultimately Snow Grain Size Measurements?

    Science.gov (United States)

    Schneider, A. M.; Flanner, M.; Yang, P.; Yi, B.; Huang, X.; Feldman, D.

    2016-12-01

    The Snow Grain Size and Pollution (SGSP) algorithm is a method applied to Moderate Resolution Imaging Spectroradiometer data to estimate snow grain size from space-borne measurements. Previous studies validate and quantify potential sources of error in this method, but because it assumes flat snow surfaces, however, large scale variations in surface normals can cause biases in its estimates due to its dependence on solar and observation zenith angles. To address these variations, we apply the Monte Carlo method for photon transport using data containing the single scattering properties of different ice crystals to calculate polarization states of reflected monochromatic light at 1500nm from modeled snow surfaces. We evaluate the dependence of these polarization states on solar and observation geometry at 1500nm because multiple scattering is generally a mechanism for depolarization and the ice crystals are relatively absorptive at this wavelength. Using 1500nm thus results in a higher number of reflected photons undergoing fewer scattering events, increasing the likelihood of reflected light having higher degrees of polarization. In evaluating the validity of the model, we find agreement with previous studies pertaining to near-infrared spectral directional hemispherical reflectance (i.e. black-sky albedo) and similarities in measured bidirectional reflectance factors, but few studies exist modeling polarization states of reflected light from snow surfaces. Here, we present novel results pertaining to calculated polarization states and compare dependences on solar and observation geometry for different idealized snow surfaces. If these dependencies are consistent across different ice particle shapes and sizes, then these findings could inform the SGSP algorithm by providing useful relationships between measurable physical quantities and solar and observation geometry to better understand variations in snow surface normals from remote sensing observations.

  7. Hydrologic parameters and land use reflection on water quality at Mun river, Thailand

    International Nuclear Information System (INIS)

    Akter, A.; Babel, M.S.

    2005-01-01

    The 'River Basin' is the land area surrounding one river from its headwaters to its mouth whereas the area drained by a river and its tributaries. So that the land use changes and excessive application of nutrients (Nitrogen and Phosphorus) in predominant agricultural river basins may have a great influence on water quality. Here the study area Mun River Basin is approximately of 69,701 km/sup 2/ and in 1994, out of the total basin area 'about 80 percent was covered by agricultural purposes. Also one of the driest parts of Thailand as well as one of the industrialized provinces in Thailand, Nakhon Ratchasima is situated at the upstream of the river. Accordingly the downstream part Ubon Ratchathani seems totally agricultural based area. To get the water quality changing trends due to land use, there are around forty water quality parameters has considered for the last ten years along with the basins hydrological parameters. For this study based on the fifteen years rainfall data, the whole year divided into two seasons namely wet season (May to October) and dry season (November to April). The result shows: (1) most of the physicochemical parameters are high in wet season; (2) heavy metals moreover appear higher at wet season and (3) although the presences of pesticides are very nominal, the higher values are detected at wet season. The conclusion draws for the water quality by having wet season water sampling and then the testing of water samples for selected seven parameters whereas the water samples are collected at a duration of one-week to three-week from April to October 2004. And this short duration analysis shows that the mean value of the nutrient shows not only higher at wet season (May to October) than April's data also exceed the existing Thailand's surface water quality standard. (author)

  8. Influence of materials in reflection of the high and the luminous quality; Influencia de los materiales en la reflexion de la luz y en la caulidad del espacio lminoso

    Energy Technology Data Exchange (ETDEWEB)

    Piderit, M. B.

    2004-07-01

    This study objective of was to define the aspects of the surfaces and the materials that influence in the reflection of the light and the luminous quality of the architectonic space, to generate a tool of application to the architecture project. In the first part, a study is made of different surfaces to define photometric aspects and qualitative aspects for the typologies elaboration . The following stage included the analysis of different materials to establish the aspects that modify the photometry of the surface and the luminous quality. The conclusions show the importance of the correct election of the type of surface and materiality to obtain the wished luminosity. (Author)

  9. Exploration of a Polarized Surface Bidirectional Reflectance Model Using the Ground-Based Multiangle SpectroPolarimetric Imager

    Directory of Open Access Journals (Sweden)

    David J. Diner

    2012-12-01

    Full Text Available Accurate characterization of surface reflection is essential for retrieval of aerosols using downward-looking remote sensors. In this paper, observations from the Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI are used to evaluate a surface polarized bidirectional reflectance distribution function (PBRDF model. GroundMSPI is an eight-band spectropolarimetric camera mounted on a rotating gimbal to acquire pushbroom imagery of outdoor landscapes. The camera uses a very accurate photoelastic-modulator-based polarimetric imaging technique to acquire Stokes vector measurements in three of the instrument’s bands (470, 660, and 865 nm. A description of the instrument is presented, and observations of selected targets within a scene acquired on 6 January 2010 are analyzed. Data collected during the course of the day as the Sun moved across the sky provided a range of illumination geometries that facilitated evaluation of the surface model, which is comprised of a volumetric reflection term represented by the modified Rahman-Pinty-Verstraete function plus a specular reflection term generated by a randomly oriented array of Fresnel-reflecting microfacets. While the model is fairly successful in predicting the polarized reflection from two grass targets in the scene, it does a poorer job for two manmade targets (a parking lot and a truck roof, possibly due to their greater degree of geometric organization. Several empirical adjustments to the model are explored and lead to improved fits to the data. For all targets, the data support the notion of spectral invariance in the angular shape of the unpolarized and polarized surface reflection. As noted by others, this behavior provides valuable constraints on the aerosol retrieval problem, and highlights the importance of multiangle observations.

  10. Non-invasive identification of metal-oxalate complexes on polychrome artwork surfaces by reflection mid-infrared spectroscopy.

    Science.gov (United States)

    Monico, Letizia; Rosi, Francesca; Miliani, Costanza; Daveri, Alessia; Brunetti, Brunetto G

    2013-12-01

    In this work a reflection mid-infrared spectroscopy study of twelve metal-oxalate complexes, of interest in art conservation science as alteration compounds, was performed. Spectra of the reference materials highlighted the presence of derivative-like and/or inverted features for the fundamental vibrational modes as result of the main contribution from the surface component of the reflected light. In order to provide insights in the interpretation of theses spectral distortions, reflection spectra were compared with conventional transmission ones. The Kramers-Kronig (KK) algorithm, employed to correct for the surface reflection distortions, worked properly only for the derivative-like bands. Therefore, to pay attention to the use of this algorithm when interpreting the reflection spectra is recommended. The outcome of this investigation was exploited to discriminate among different oxalates on thirteen polychrome artworks analyzed in situ by reflection mid-infrared spectroscopy. The visualization of the νs(CO) modes (1400-1200 cm(-1)) and low wavenumber bands (below 900 cm(-1)) in the raw reflection profiles allowed Ca, Cu and Zn oxalates to be identified. Further information about the speciation of different hydration forms of calcium oxalates were obtained by using the KK transform. The work proves reflection mid-infrared spectroscopy to be a reliable and sensitive spectro-analytical method for identifying and mapping different metal-oxalate alteration compounds on the surface of artworks, thus providing conservation scientists with a non-invasive tool to obtain information on the state of conservation and causes of alteration of artworks. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Surface and groundwater quality assessment of Marikina river

    International Nuclear Information System (INIS)

    Dela Pena, Jowell P.; Pael, Limela G.

    2009-03-01

    The study used the physico-chemical characteristics to determine the degree of pollution in different surface and groundwater sources in Marikina. The hydrogen ion concentration in all the stations for surface water was generally basic ranging from 7.24 to 7.44, while conductivity was observed to be highest in Royal Ville station that has a value of 253 μ/cm. Among the four stations in groundwater which obtained an acidic pH, Brgy. Singkamas deep-well has a neutral value. The conductivity was observed to be highest in Brgy. Conception which has a value of 1026 μ/cm. The major ions result showed that the three stations from Marikina River have conformed to the water quality criteria for fresh waters set by the Department of Environment and Natural Resources, while results from different deep-well stations showed that among four stations, Brgy. Singkamas and Conception deep-well have exceeded the recommended value concentration for drinking water quality standards. The multi-element results were obtained from an Energy-Dispersive X-ray Fluorescence Spectroscopy. Results showed that significant concentrations of metals like Al, Cd, Cr, Fe, and Pb in both surface and groundwater stations have exceeded the maximum concentrations set by both DENR and PNSDW. The significant differences in the concentrations of physico-chemical components facilitate detection of contamination from domestic and industrial wastes. (author)

  12. A new theory and its application to remove the effect of surface-reflected light in above-surface radiance data from clear and turbid waters

    International Nuclear Information System (INIS)

    Dev, Pravin Jeba; Shanmugam, Palanisamy

    2014-01-01

    Water-leaving radiances (L w ) measured from the deck of a ship or boat in oceanic and lake waters are widely and operationally used for satellite sensor vicarious calibration and validation and development of remote-sensing algorithms to understand interdisciplinary coastal ocean properties and processes. However, accurate determination of L w remains to be a challenging issue because of the limitations of the existing methods to accurately remove the undesired signal (surface-reflected light of the sky and sun) from above-surface measurements of the total upwelling radiance leaving the water surface. In this study, a new theory is developed and applied to the above-surface radiometric data measured from clear, turbid and eutrophic waters. The new method effectively removes surface-reflected contributions from the total upwelling radiance signal under different sky (clear sky to overcast sky) and sun glint conditions. The L w spectra obtained from the above-surface radiance data using the new method are found to match well with those extrapolated from the upwelling radiances (L u ) measured with another set of underwater radiometers (used just below the sea surface). The new method proves to be a viable alternative, especially in circumstances when the above-surface measurements of radiances are severally contaminated by the surface-reflected light fields. Since spectral radiance measurements are also sensitive to the observation angles, and to the magnitude of the radiometer's solid angle field of view, above-surface radiances are also measured for different viewing angles in highly eutrophic waters. Such measurements show large deviations in L w spectra except at lower viewing angles (30°). When applied to these data, the new method eliminates the undesired signal encountered at higher viewing angles and delivers accurate water-leaving radiance data. These results suggest that the new method is capable of removing the surface-reflected light fields from both

  13. Does feather corticosterone reflect individual quality or external stress in arctic-nesting migratory birds?

    Directory of Open Access Journals (Sweden)

    Pierre Legagneux

    Full Text Available The effects of environmental perturbations or stressors on individual states can be carried over to subsequent life stages and ultimately affect survival and reproduction. The concentration of corticosterone (CORT in feathers is an integrated measure of hypothalamic-pituitary-adrenal activity during the molting period, providing information on the total baseline and stress-induced CORT secreted during the period of feather growth. Common eiders and greater snow geese replace all flight feathers once a year during the pre-basic molt, which occurs following breeding. Thus, CORT contained in feathers of pre-breeding individuals sampled in spring reflects the total CORT secreted during the previous molting event, which may provide insight into the magnitude or extent of stress experienced during this time period. We used data from multiple recaptures to disentangle the contribution of individual quality vs. external factors (i.e., breeding investment or environmental conditions on feather CORT in arctic-nesting waterfowl. Our results revealed no repeatability of feather CORT within individuals of either species. In common eiders, feather CORT was not affected by prior reproductive investment, nor by pre-breeding (spring body condition prior to the molting period. Individual feather CORT greatly varied according to the year, and August-September temperatures explained most of the annual variation in feather CORT. Understanding mechanisms that affect energetic costs and stress responses during molting will require further studies either using long-term data or experiments. Although our study period encompassed only five years, it nonetheless provides evidence that CORT measured in feathers likely reflects responses to environmental conditions experienced by birds during molt, and could be used as a metric to study carry-over effects.

  14. Does feather corticosterone reflect individual quality or external stress in arctic-nesting migratory birds?

    Science.gov (United States)

    Legagneux, Pierre; Harms, N Jane; Gauthier, Gilles; Chastel, Olivier; Gilchrist, H Grant; Bortolotti, Gary; Bêty, Joël; Soos, Catherine

    2013-01-01

    The effects of environmental perturbations or stressors on individual states can be carried over to subsequent life stages and ultimately affect survival and reproduction. The concentration of corticosterone (CORT) in feathers is an integrated measure of hypothalamic-pituitary-adrenal activity during the molting period, providing information on the total baseline and stress-induced CORT secreted during the period of feather growth. Common eiders and greater snow geese replace all flight feathers once a year during the pre-basic molt, which occurs following breeding. Thus, CORT contained in feathers of pre-breeding individuals sampled in spring reflects the total CORT secreted during the previous molting event, which may provide insight into the magnitude or extent of stress experienced during this time period. We used data from multiple recaptures to disentangle the contribution of individual quality vs. external factors (i.e., breeding investment or environmental conditions) on feather CORT in arctic-nesting waterfowl. Our results revealed no repeatability of feather CORT within individuals of either species. In common eiders, feather CORT was not affected by prior reproductive investment, nor by pre-breeding (spring) body condition prior to the molting period. Individual feather CORT greatly varied according to the year, and August-September temperatures explained most of the annual variation in feather CORT. Understanding mechanisms that affect energetic costs and stress responses during molting will require further studies either using long-term data or experiments. Although our study period encompassed only five years, it nonetheless provides evidence that CORT measured in feathers likely reflects responses to environmental conditions experienced by birds during molt, and could be used as a metric to study carry-over effects.

  15. Land Surface Reflectance Retrieval from Hyperspectral Data Collected by an Unmanned Aerial Vehicle over the Baotou Test Site

    Science.gov (United States)

    Duan, Si-Bo; Li, Zhao-Liang; Tang, Bo-Hui; Wu, Hua; Ma, Lingling; Zhao, Enyu; Li, Chuanrong

    2013-01-01

    To evaluate the in-flight performance of a new hyperspectral sensor onboard an unmanned aerial vehicle (UAV-HYPER), a comprehensive field campaign was conducted over the Baotou test site in China on 3 September 2011. Several portable reference reflectance targets were deployed across the test site. The radiometric performance of the UAV-HYPER sensor was assessed in terms of signal-to-noise ratio (SNR) and the calibration accuracy. The SNR of the different bands of the UAV-HYPER sensor was estimated to be between approximately 5 and 120 over the homogeneous targets, and the linear response of the apparent reflectance ranged from approximately 0.05 to 0.45. The uniform and non-uniform Lambertian land surface reflectance was retrieved and validated using in situ measurements, with root mean square error (RMSE) of approximately 0.01–0.07 and relative RMSE of approximately 5%–12%. There were small discrepancies between the retrieved uniform and non-uniform Lambertian land surface reflectance over the homogeneous targets and under low aerosol optical depth (AOD) conditions (AOD = 0.18). However, these discrepancies must be taken into account when adjacent pixels had large land surface reflectance contrast and under high AOD conditions (e.g. AOD = 1.0). PMID:23785513

  16. A monthly quality assurance procedure for 3D surface imaging.

    Science.gov (United States)

    Wooten, H Omar; Klein, Eric E; Gokhroo, Garima; Santanam, Lakshmi

    2010-12-21

    A procedure for periodic quality assurance of a video surface imaging system is introduced. AlignRT is a video camera-based patient localization system that captures and compares images of a patient's topography to a DICOM-formatted external contour, then calculates shifts required to accurately reposition the patient. This technical note describes the tools and methods implemented in our department to verify correct and accurate operation of the AlignRT hardware and software components. The procedure described is performed monthly and complements a daily calibration of the system.

  17. Synchrotron Radiation Total Reflection X-ray Fluorescence Spectroscopy for Microcontamination Analysis on Silicon Wafer Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Takaura, Norikatsu

    1997-10-01

    As dimensions in state-of-the-art CMOS devices shrink to less than 0.1 pm, even low levels of impurities on wafer surfaces can cause device degradation. Conventionally, metal contamination on wafer surfaces is measured using Total Reflection X-Ray Fluorescence Spectroscopy (TXRF). However, commercially available TXRF systems do not have the necessary sensitivity for measuring the lower levels of contamination required to develop new CMOS technologies. In an attempt to improve the sensitivity of TXRF, this research investigates Synchrotron Radiation TXRF (SR TXRF). The advantages of SR TXRF over conventional TXRF are higher incident photon flux, energy tunability, and linear polarization. We made use of these advantages to develop an optimized SR TXRF system at the Stanford Synchrotron Radiation Laboratory (SSRL). The results of measurements show that the Minimum Detection Limits (MDLs) of SR TXRF for 3-d transition metals are typically at a level-of 3x10{sup 8} atoms/cm{sup 2}, which is better than conventional TXRF by about a factor of 20. However, to use our SR TXRF system for practical applications, it was necessary to modify a commercially available Si (Li) detector which generates parasitic fluorescence signals. With the modified detector, we could achieve true MDLs of 3x10{sup 8} atoms/cm{sup 2} for 3-d transition metals. In addition, the analysis of Al on Si wafers is described. Al analysis is difficult because strong Si signals overlap the Al signals. In this work, the Si signals are greatly reduced by tuning the incident beam energy below the Si K edge. The results of our measurements show that the sensitivity for Al is limited by x-ray Raman scattering. Furthermore, we show the results of theoretical modeling of SR TXRF backgrounds consisting of the bremsstrahlung generated by photoelectrons, Compton scattering, and Raman scattering. To model these backgrounds, we extended conventional theoretical models by taking into account several aspects particular

  18. Optical performance of random anti-reflection structured surfaces (rARSS) on spherical lenses

    Science.gov (United States)

    Taylor, Courtney D.

    Random anti-reflection structured surfaces (rARSS) have been reported to improve transmittance of optical-grade fused silica planar substrates to values greater than 99%. These textures are fabricated directly on the substrates using reactive-ion/inductively-coupled plasma etching (RIE/ICP) techniques, and often result in transmitted spectra with no measurable interference effects (fringes) for a wide range of wavelengths. The RIE/ICP processes used in the fabrication process to etch the rARSS is anisotropic and thus well suited for planar components. The improvement in spectral transmission has been found to be independent of optical incidence angles for values from 0° to +/-30°. Qualifying and quantifying the rARSS performance on curved substrates, such as convex lenses, is required to optimize the fabrication of the desired AR effect on optical-power elements. In this work, rARSS was fabricated on fused silica plano-convex (PCX) and plano-concave (PCV) lenses using a planar-substrate optimized RIE process to maximize optical transmission in the range from 500 to 1100 nm. An additional set of lenses were etched in a non-optimized ICP process to provide additional comparisons. Results are presented from optical transmission and beam propagation tests (optimized lenses only) of rARSS lenses for both TE and TM incident polarizations at a wavelength of 633 nm and over a 70° full field of view in both singlet and doublet configurations. These results suggest optimization of the fabrication process is not required, mainly due to the wide angle-of-incidence AR tolerance performance of the rARSS lenses. Non-optimized recipe lenses showed low transmission enhancement, and confirmed the need to optimized etch recipes prior to process transfer of PCX/PCV lenses. Beam propagation tests indicated no major beam degradation through the optimized lens elements. Scanning electron microscopy (SEM) images confirmed different structure between optimized and non-optimized samples

  19. To what extent do food purchases reflect shoppers' diet quality and nutrient intake?

    Science.gov (United States)

    Appelhans, Bradley M; French, Simone A; Tangney, Christy C; Powell, Lisa M; Wang, Yamin

    2017-04-11

    Food purchasing is considered a key mediator between the food environment and eating behavior, and food purchasing patterns are increasingly measured in epidemiologic and intervention studies. However, the extent to which food purchases actually reflect individuals' dietary intake has not been rigorously tested. This study examined cross-sectional agreement between estimates of diet quality and nutrient densities derived from objectively documented household food purchases and those derived from interviewer-administered 24-h diet recalls. A secondary aim was to identify moderator variables associated with attenuated agreement between purchases and dietary intake. Primary household food shoppers (N = 196) collected and annotated receipts for all household food and beverage purchases (16,356 total) over 14 days. Research staff visited participants' homes four times to photograph the packaging and nutrition labels of each purchased item. Three or four multiple-pass 24-h diet recalls were performed within the same 14-d period. Nutrient densities and Healthy Eating Index-2010 (HEI-2010) scores were calculated from both food purchase and diet recall data. HEI-2010 scores derived from food purchases (median = 60.9, interquartile range 49.1-71.7) showed moderate agreement (ρc = .57, p social desirability, household income, household size, and body mass. Concordance for individual nutrient densities from food purchases and 24-h diet recalls varied widely from ρc = .10 to .61, with the strongest associations observed for fiber (ρc = .61), whole fruit (ρc = .48), and vegetables (ρc = .39). Objectively documented household food purchases yield an unbiased and reasonably accurate estimate of overall diet quality as measured through 24-h diet recalls, but are generally less useful for characterizing dietary intake of specific nutrients. Thus, some degree of caution is warranted when interpreting food purchase data as a reflection of diet in

  20. Simulation of reflectance from white-anodised aluminium surfaces using polyurethane–TiO2 composite coatings

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Johansen, Villads Egede; Ambat, Rajan

    2015-01-01

    of anodised surfaces. PU matrix was selected for its matching refractive-index (n = 1.7) with anodic alumina layer. Three different TiO2 particle size distributions were dispersed in PU and spin coated onto bright high-gloss and matte caustic-etched aluminium substrates. The reflectance spectra of coated...

  1. Model for the ultrasound reflection from micro-beads and cells distributed in layers on a uniform surface

    Energy Technology Data Exchange (ETDEWEB)

    Couture, O; Cherin, E; Foster, F S [Imaging Research, Sunnybrook Health Sciences Centre/University of Toronto, Toronto (Canada)

    2007-07-21

    A model predicting the reflection of ultrasound from multiple layers of small scattering spheres is developed. Predictions of the reflection coefficient, which takes into account the interferences between the different sphere layers, are compared to measurements performed in the 10-80 MHz and 15-35 MHz frequency range with layers of glass beads and spherical acute myeloid leukemia (AML) cells, respectively. For both types of scatterers, the reflection coefficient increases as a function of their density on the surface for less than three superimposed layers, at which point it saturates at 0.38 for glass beads and 0.02 for AML cells. Above three layers, oscillations of the reflection coefficient due to constructive or destructive interference between layers are observed experimentally and are accurately predicted by the model. The use of such a model could lead to a better understanding of the structures observed in layered tissue images.

  2. Application of the surface reflection seismic method to shallow coal exploration in the plains of Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Lyatsky, H.V.; Lawton, D.C. (University of Victoria, Victoria, BC (Canada). Dept. of Physics and Astronomy)

    1988-12-01

    A study was done to make a quantitative interpretation of reflection seismic data from the Highvale-Whitewood shallow coal deposit in central Alberta. Results showed that the data is useful in demonstrating coal thickness and stratigraphy as well as structural formation. Reflection character is affected by nature of the strata surrounding the coal deposit. 22 refs., 1 tab., 23 figs.

  3. Estuarine habitat quality reflects urbanization at large spatial scales in South Carolina's coastal zone.

    Science.gov (United States)

    Van Dolah, Robert F; Riekerk, George H M; Bergquist, Derk C; Felber, Jordan; Chestnut, David E; Holland, A Fredrick

    2008-02-01

    analyses support the hypotheses that estuarine habitat quality reflects upland development patterns at large spatial scales, and that upland urbanization can result in increased risk of biological degradation and reduced safe human use of South Carolina's coastal resources.

  4. Current status of quality evaluation of nursing care through director review and reflection from the Nursing Quality Control Centers

    OpenAIRE

    Duan, Xia; Shi, Yan

    2014-01-01

    Background: The quality evaluation of nursing care is a key link in medical quality management. It is important and worth studying for the nursing supervisors to know the disadvantages during the process of quality evaluation of nursing care and then to improve the whole nursing quality. This study was to provide director insight on the current status of quality evaluation of nursing care from Nursing Quality Control Centers (NQCCs). Material and Methods: This qualitative study used a sample ...

  5. Quality evaluation of regional forage resources by means of near infrared reflectance spectroscopy

    Directory of Open Access Journals (Sweden)

    Bruno Ronchi

    2010-01-01

    Full Text Available Quality parameters of grassland and pasture samples collected during a three-year period at two environmentally andgeographically different areas were analysed by Near Infrared Reflectance Spectroscopy (NIRS. Chemical analysis forcrude protein (CP, crude fibre (CF, neutral detergent fibre (NDF, acid detergent fibre (ADF, acid detergent lignin (ADLand crude ash (ASH carried out on two-thirds of the samples were used in calibration processes. The remaining onethirdof the data was used to validate the best calibrations obtained. Samples selection is discussed. Different math pretreatments(derivative, gap, primary smoothing and secondary smoothing, light scattering correction methods and calibrationalgorithms were tested to achieve the better predictive performances. We obtained the best results using differentregression algorithms to correlate spectral information to chemical data. For CP (R2 = 0.94, SEP=1.3, NDF (R2 =0.95, SEP = 2.14 and ADF (R2 = 0.92, SEP=2.06 Multiple Linear Regression (MLR models fit chemical data better thanMean Partial Least Square (MPLS regression. A molecular basis explanation of wavelengths selected was carried out.MPLS models worked well for CF (R2 = 0.93, SEP=1.57, and ASH (R2 = 0.95, SEP=1.17 while poor calibrations wereobtained for ADL using both algorithms. To confirm the reliability of the models developed, uncertainties of predictionswere compared with findings on nutritional variations and animal performances.

  6. Study on the effect of ambient gas on nanostructure formation on metal surfaces during femtosecond laser ablation for fabrication of low-reflective surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smausz, Tomi, E-mail: tomi@physx.u-szeged.hu [MTA-SZTE Research Group on Photoacoustic Spectroscopy, University of Szeged, 6720 Szeged, Dóm tér 9 (Hungary); Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); Csizmadia, Tamás [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); Attosecond Light Pulse Source, ELI-Hu Nkft, H-6720 Szeged, Dugonics ter 13 (Hungary); Tápai, Csaba; Kopniczky, Judit [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); Oszkó, Albert [Department of Physical Chemistry and Material Science, University of Szeged, H-6720 Szeged, Aradi vértanuk tere 1 (Hungary); Ehrhardt, Martin; Lorenz, Pierre; Zimmer, Klaus; Prager, Andrea [Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstr. 15, 04318 Leipzig (Germany); Hopp, Béla [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary)

    2016-12-15

    Highlights: • Metal surfaces were irradiated with femtosecond laser in different gas environments. • The reflectivity, morphology and chemical composition of the surfaces were studied. • Darkening was influenced by chemical and physical interaction of the plume and gas. • Molecular mass of the applied gas had an impact on the nanostructure formation. • For some of the used metals the oxide formation affected the reflective properties. - Abstract: Nanostructure formation on bulk metals (silver, gold, copper and titanium) by femtosecond Ti-sapphire laser irradiation (775 nm, 150 fs) is studied aiming the production of low-reflectivity surfaces and the better understanding of the development process. The experiments were performed in nitrogen, air, oxygen and helium environments at atmospheric pressure. The samples were irradiated with fluences in the 0.1–2 J/cm{sup 2} range and an average pulse number of 100 falling over a given area. The reflectivity of the treated surfaces was determined by a microspectrometer in the 450–800 nm range and their morphology was studied by scanning electron microscopy. The gas ambience influenced the results via two effects: formation processes and the chemically-induced modifications of the nanostructures. In case of He the nanoparticle aggregates–otherwise generally present–are predominantly missing, which leads to a lower darkening efficiency. The presence of oxygen enhances the darkening effect for copper mostly at lower fluences, while causes a slow increase in reflectivity in the case of titanium (in case of pure oxygen) in the high fluence range. The surface morphology in case of nitrogen and air were quite similar probably due to their close molecular mass values.

  7. Quality of the surface of Coffea arabica wood

    Directory of Open Access Journals (Sweden)

    Pedro Paulo de Carvalho Braga

    2014-03-01

    Full Text Available The wood of Coffea arabica L. is considered a a residue of the coffee industry and is widely used as a source of energy. Few studies have shown other destinations such as the manufacture of small objects and furniture with rustic design. The objective of this work was to find the best fit in cutting speed during machining planer trowel the wood of Coffea arabica, taking into consideration the quality of the machined surface. The wood from the Coffea arabica came from an 15 years planting, spacing 3 x 2 m, of the municipality of Machado / MG. The tree was pruned, unfolded and flattened, in order for getting cut-proof of 30 mm thick, with variables length and width. The machining tests were performed at the Laboratory of Wood Machining (DCF / UFLA, varying the cutting speed in plane trowel. The qualification of the machined surface was performed by the feed per tooth (fz, visual analysis (ASTM D 1666-87 and roughness Ra and Rz. It was used a completely randomized design with 30 repetitions. We conducted the analysis of variance test and the average of Scott-Knott, at 5% significance level. It was calculated the percentage of marks obtained for the feed per tooth. The results showed that the quality of machined surface with cutting speeds of 19 and 21 m∙s-1 and forward speed of 6 m∙min-1 were satisfactory with small surveys of fiber and low values of feed per tooth ( fz and roughness Ra and Rz.

  8. Determining the influential depth for surface reflectance of sediment by BRDF measurements.

    Science.gov (United States)

    Zhang, H; Voss, K; Reid, R

    2003-10-20

    We measure the Bi-directional reflectance distribution function (BRDF) of ooid sand layers with three particle size distributions (0.5-1mm, 0.25-0.5mm and 0.125-0.25mm) and layer thicknesses on a reflecting mirror to determine the influential depth in the optical region at wavelengths of 658 nm (red), 570 nm (green) and 457 nm (blue). The hemispherical reflectance (albedo) was used as an indicator of BRDF changes between different layers. Measurements are carried out on both dry and water wetted grains. The results indicate that for both dry and wet and all size distributions, the influential depth is at most 2mm.

  9. Surface Water Quality Trends from EPA's LTM Network

    Science.gov (United States)

    Funk, C.; Lynch, J. A.

    2013-12-01

    Surface water chemistry provides direct indicators of the potential effects of anthropogenic impacts, such as acid deposition and climate change, on the overall health of aquatic ecosystems. Long-term surface water monitoring networks provide a host of environmental data that can be used, in conjunction with other networks, to assess how water bodies respond to stressors and if they are potentially at risk (e.g., receiving pollutant deposition beyond its critical load). Two EPA-administered monitoring programs provide information on the effects of acidic deposition on headwater aquatic systems: the Long Term Monitoring (LTM) program and the Temporally Integrated Monitoring of Ecosystems (TIME) program, designed to track the effectiveness of the 1990 Clean Air Act Amendments (CAAA) in reducing the acidity of surface waters in acid sensitive ecoregions of the Northeast and Mid-Atlantic. Here we present regional variability of long term trends in surface water quality in response to substantial reductions in atmospheric deposition. Water quality trends at acid sensitive LTM sites exhibit decreasing concentrations of sulfate at 100% of monitored sites in the Adirondack Mountains and New England, 80% of Northern Appalachian Plateau sites, and yet only 15% of sites in the Ridge and Blue Ridge Provinces over the 1990-2011 period of record. Across all regions, most LTM sites exhibited constant or only slightly declining nitrate concentrations over the same time period. Acid Neutralizing Capacity (ANC) levels improved at 68% and 45% of LTM sites in the Adirondacks and Northern Appalachian Plateau, respectively, but few sites showed increases in New England or the Ridge and Blue Ridge Provinces due to lagging improvements in base cation concentration. The ANC of northeastern TIME lakes was also evaluated from 1991 to 1994 and 2008 to 2011. The percentage of lakes with ANC values below 50 μeq/L, lakes of acute or elevated concern, dropped by about 7%, indicating improvement

  10. Coil Tolerance Impact on Plasma Surface Quality for NCSX

    International Nuclear Information System (INIS)

    Brooks, Art; Reiersen, Wayne

    2003-01-01

    The successful operation of the National Compact Stellarator Experiment (NCSX) machine will require producing plasma configurations with good flux surfaces, with a minimum volume of the plasma lost to magnetic islands or stochastic regions. The project goal is to achieve good flux surfaces over 90% of the plasma volume. NCSX is a three period device designed to be operated with iota ranging from ∼0.4 on axis to ∼0.7 at the edge. The field errors of most concern are those that are resonant with 3/5 and 3/6 modes (for symmetry preserving field errors) and the 1/2 and 2/3 modes (for symmetry breaking field errors). In addition to losses inherent in the physics configuration itself, there will be losses from field errors arising from coil construction and assembly errors. Some of these losses can be recovered through the use of trim coils or correction coils. The impact of coil tolerances on plasma surface quality is evaluated herein for the NCSX design. The methods used in this evaluation are discussed. The ability of the NCSX trim coils to correct for field errors is also examined. The results are used to set coils tolerances for the various coil systems

  11. Variability of the reflectance coefficient of skylight from the ocean surface and its implications to ocean color.

    Science.gov (United States)

    Gilerson, Alexander; Carrizo, Carlos; Foster, Robert; Harmel, Tristan

    2018-04-16

    The value and spectral dependence of the reflectance coefficient (ρ) of skylight from wind-roughened ocean surfaces is critical for determining accurate water leaving radiance and remote sensing reflectances from shipborne, AERONET-Ocean Color and satellite observations. Using a vector radiative transfer code, spectra of the reflectance coefficient and corresponding radiances near the ocean surface and at the top of the atmosphere (TOA) are simulated for a broad range of parameters including flat and windy ocean surfaces with wind speeds up to 15 m/s, aerosol optical thicknesses of 0-1 at 440nm, wavelengths of 400-900 nm, and variable Sun and viewing zenith angles. Results revealed a profound impact of the aerosol load and type on the spectral values of ρ. Such impacts, not included yet in standard processing, may produce significant inaccuracies in the reflectance spectra retrieved from above-water radiometry and satellite observations. Implications for satellite cal/val activities as well as potential changes in measurement and data processing schemes are discussed.

  12. Evaluation of the global MODIS 30 arc-second spatially and temporally complete snow-free land surface albedo and reflectance anisotropy dataset

    Science.gov (United States)

    Sun, Qingsong; Wang, Zhuosen; Li, Zhan; Erb, Angela; Schaaf, Crystal B.

    2017-06-01

    Land surface albedo is an essential variable for surface energy and climate modeling as it describes the proportion of incident solar radiant flux that is reflected from the Earth's surface. To capture the temporal variability and spatial heterogeneity of the land surface, satellite remote sensing must be used to monitor albedo accurately at a global scale. However, large data gaps caused by cloud or ephemeral snow have slowed the adoption of satellite albedo products by the climate modeling community. To address the needs of this community, we used a number of temporal and spatial gap-filling strategies to improve the spatial and temporal coverage of the global land surface MODIS BRDF, albedo and NBAR products. A rigorous evaluation of the gap-filled values shows good agreement with original high quality data (RMSE = 0.027 for the NIR band albedo, 0.020 for the red band albedo). This global snow-free and cloud-free MODIS BRDF and albedo dataset (established from 2001 to 2015) offers unique opportunities to monitor and assess the impact of the changes on the Earth's land surface.

  13. Native SrTiO3 (001) surface layer from resonant Ti L2,3 reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Valvidares, Manuel; Huijben, Mark; Yu, Pu; Ramesh, Ramamoorthy; Kortright, Jeffrey

    2010-11-03

    We quantitatively model resonant Ti L2,3 reflectivity Rs,p(q, hn) from several SrTiO3 (001) single crystals having different initial surface preparations and stored in ambient conditions before and between measurements. All samples exhibit unexpected 300 K Rs(hn) - Rp(hn) anisotropy corresponding to weak linear dichroism and tetragonal distortion of the TiO6 octahedra indicating a surface layer with properties different from cubic SrTiO3. Oscillations in Rs(q) confirm a ubiquitous surface layer 2-3 nm thick that evolves over a range of time scales. Resonant optical constant spectra derived from Rs,p(hn) assuming a uniform sample are refined using a single surface layer to fit measured Rs(q). Differences in surface layer and bulk optical properties indicate that the surface is significantly depleted in Sr and enriched in Ti and O. While consistent with the tendency of SrTiO3 surfaces toward non-stoichiometry, this layer does not conform simply to existing models for the near surface region and apparently forms via room temperature surface reactions with the ambient. This new quantitative spectral modeling approach is generally applicable and has potential to study near-surface properties of a variety of systems with unique chemical and electronic sensitivities.

  14. X-ray reflectivity study of thermal capillary waves on liquid surfaces

    International Nuclear Information System (INIS)

    Ocko, B.M.; Wu, X.Z.; Sirota, E.B.; Sinha, S.K.; Deutsch, M.

    1994-01-01

    X-ray reflectivity measurements have been carried out at the liquid/vapor interface of normal alkanes. The reflectivities over a large temperature range of different chain lengths (C20 and C36) provide a critical test of the various capillary wave models. Our data are most consistent with the hybrid model which allows for a molecular size dependent cutoff q max for the capillary waves and an intrinsic interface width σ 0

  15. Morphology and phase structures of CW laser-induced oxide layers on iron surface with evolving reflectivity and colors

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Taotao, E-mail: wutaotao@nint.ac.cn; Wang, Lijun; Wei, Chenghua; Zhou, Menglian; He, Minbo; Wu, Lixiong

    2016-11-30

    Highlights: • Firstly, iron samples with different color features were obtained by continuous wave laser irradiation depending on progressive durations. The real-time reflectivity and temperature of samples were measured. The color and the reflectivity evolution were related. They were both caused by the forming oxide films. • Secondly, laser-induced oxidation process of iron was studied by microscope, X-ray diffraction and Raman spectrum. The first formed magnetite made the surface reflectivity decline rapidly and caused the “positive feedback” effect because of molecular absorption. The later formed hematite oscillated the reflectivity by interference effect. • Lastly, the laser-induced oxide films were thin, orientated and badly crystallized. The Wagner oxidation theory was incapable of describing the non-isothermal and early stage oxidation process. So we emphasized that a precise oxidation model depending on the experiment and the optical constants of the laser-induced oxides must be studied. - Abstract: Laser-induced oxidation will change the laser reflectivity and color features of metal surface. Both changes can be theoretically calculated based on the oxidation kinetics and the optical constants of oxides. For the purpose of calculation, the laser-induced oxidation process of pure polycrystalline iron was studied. Samples with various color features were obtained by continuous wave Nd:YAG fiber laser (1.06 μm) irradiation depending on progressive durations in the intensity of 1.90 W/cm{sup 2}. The real-time reflectivity and temperature were measured with integral sphere and thermocouples. The irradiated surface morphology and phase structures were characterized by microscope, X-ray diffraction and Raman spectrum. It was found that the first formed magnetite made the surface reflectivity decline rapidly and caused the “positive feedback” effect because of molecular absorption. The later formed hematite oscillated the reflectivity by

  16. Learning How to Write an Academic Text: The Effect of Instructional Method and Reflection on Text Quality

    Science.gov (United States)

    van der Loo, Janneke; Krahmer, Emiel; van Amelsvoort, Marije

    2016-01-01

    In this paper we present preliminary results on a study on the effect of instructional method (observational learning and learning by doing) and reflection (yes or no) on academic text quality and self-efficacy beliefs. 56 undergraduate students were assigned to either an observational learning or learning-by-doing condition, with or without…

  17. Kaguya observations of the lunar wake in the terrestrial foreshock: Surface potential change by bow-shock reflected ions

    Science.gov (United States)

    Nishino, Masaki N.; Harada, Yuki; Saito, Yoshifumi; Tsunakawa, Hideo; Takahashi, Futoshi; Yokota, Shoichiro; Matsushima, Masaki; Shibuya, Hidetoshi; Shimizu, Hisayoshi

    2017-09-01

    There forms a tenuous region called the wake behind the Moon in the solar wind, and plasma entry/refilling into the wake is a fundamental problem of the lunar plasma science. High-energy ions and electrons in the foreshock of the Earth's magnetosphere were detected at the lunar surface in the Apollo era, but their effects on the lunar night-side environment have never been studied. Here we show the first observation of bow-shock reflected protons by Kaguya (SELENE) spacecraft in orbit around the Moon, confirming that solar wind plasma reflected at the terrestrial bow shock can easily access the deepest lunar wake when the Moon stays in the foreshock (We name this mechanism 'type-3 entry'). In a continuous type-3 event, low-energy electron beams from the lunar night-side surface are not obvious even though the spacecraft location is magnetically connected to the lunar surface. On the other hand, in an intermittent type-3 entry event, the kinetic energy of upward-going field-aligned electron beams decreases from ∼ 80 eV to ∼ 20 eV or electron beams disappear as the bow-shock reflected ions come accompanied by enhanced downward electrons. According to theoretical treatment based on electric current balance at the lunar surface including secondary electron emission by incident electron and ion impact, we deduce that incident ions would be accompanied by a few to several times higher flux of an incident electron flux, which well fits observed downward fluxes. We conclude that impact by the bow-shock reflected ions and electrons raises the electrostatic potential of the lunar night-side surface.

  18. Coherent reflection from surface gravity water waves during reciprocal acoustic transmissions.

    Science.gov (United States)

    Badiey, Mohsen; Song, Aijun; Smith, Kevin B

    2012-10-01

    During a recent experiment in Kauai, Hawaii, reciprocal transmissions were conducted between two acoustic transceivers mounted on the seafloor at a depth of 100 m. The passage of moving surface wave crests was shown to generate focused and intense coherent acoustic returns, which had increasing or decreasing delay depending on the direction of propagation relative to the direction of surface wave crests. It is shown that a rough surface two-dimensional parabolic equation model with an evolving sea surface can produce qualitative agreement with data for the dynamic surface returns.

  19. Stretched membrane heliostats: design and structural analysis of reflectance module and support of a heliostats of 9 m. diaform and 60 m''3 of reflectance surface

    International Nuclear Information System (INIS)

    Figarola Torres, J. M.

    1993-01-01

    After having designed and built at CIEMAT a first prototype of a Btretched membrane heliostats of 3 m. diameter, the design and the structural analysis of the different components included in the reflectance module and support of another heliostats, this one of 9 m. diameter and 60 m2. of reflectance surface, are shown In this report. This last heliostats will be mounted on a pedestal and its driving device at the Solar Platform of Almeria. In order to optimize design and performance, the structural analysis of its basic components has been analyzed with the finite elements program ANSYS. The following elements have been subject to analysis: the membrane and their ring supports, stretching system and the structural support. A similar scheme to the one applied to the previous prototype has been used on the focus control system. That includes a linear transducer, a variable frequency and a fan. Finally it has to be pointed out that substantial improvements have been achieved with respect to the first prototype concerning design and cost. (Author) 5 refs

  20. Impact on surface water quality due to coke oven effluents

    International Nuclear Information System (INIS)

    Ghose, M.K.; Roy, S.

    1994-01-01

    Large quantities of water are used for the quenching of hot coke and also for washing the gas produced from the coke ovens. Liquid effluents thus generated are highly polluted and are being discharged into the river Damodar without proper treatment. Four coke plants of Bharat Coking Coal Ltd.(BCCL) have been surveyed for characterization and to assess the impact on surface water quality. About 175-200 kilolitres of waste water is being generated per day by each of the coke plants. The concentration of CO, BOD, COD, TSS, phenol and cyanide in each of the coke plants were found to exceed the limits specified by pollution control board. Ammonia, oil and grease and TDS were found to be 19.33 mg/l, 7.81 mg/l, 1027.75 mg/l respectively. Types of samples collected, sampling frequencies, sample preservation and the results obtained have been discussed. (author). 6 refs., 1 tab., 1 fig

  1. Analysis of bacteria on steel surfaces using reflectance micro-Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Ojeda, Jesús J; Romero-González, María E; Banwart, Steven A

    2009-08-01

    Reflectance micro-Fourier transform infrared (FT-IR) analysis has been applied to characterize biofilm formation of Aquabacterium commune, a common microorganism present on drinking water distribution systems, onto the increasingly popular pipe material stainless steel EN1.4307. The applicability of the reflectance micro-FT-IR technique for analyzing the bacterial functional groups is discussed, and the results are compared to spectra obtained using more conventional FT-IR techniques: transmission micro-FT-IR, attenuated transmitted reflectance (ATR), and KBr pellets. The differences between the infrared spectra of wet and dried bacteria, as well as free versus attached bacteria, are also discussed. The spectra obtained using reflectance micro-FT-IR spectroscopy were comparable to those obtained using other FT-IR techniques. The absence of sample preparation, the potential to analyze intact samples, and the ability to characterize opaque and thick samples without the need to transfer the bacterial samples to an infrared transparent medium or produce a pure culture were the main advantages of reflectance micro-FT-IR spectroscopy.

  2. Current status of quality evaluation of nursing care through director review and reflection from the Nursing Quality Control Centers

    Science.gov (United States)

    Duan, Xia; Shi, Yan

    2014-01-01

    Background: The quality evaluation of nursing care is a key link in medical quality management. It is important and worth studying for the nursing supervisors to know the disadvantages during the process of quality evaluation of nursing care and then to improve the whole nursing quality. This study was to provide director insight on the current status of quality evaluation of nursing care from Nursing Quality Control Centers (NQCCs). Material and Methods: This qualitative study used a sample of 12 directors from NQCCs who were recruited from 12 provinces in China to evaluate the current status of quality evaluation of nursing care. Data were collected by in-depth interviews. Content analysis method was used to analyze the data. Results: Four themes emerged from the data: 1) lag of evaluation index; 2) limitations of evaluation content; 3) simplicity of evaluation method; 4) excessive emphasis on terminal quality. Conclusion: It is of great realistic significance to ameliorate nursing quality evaluation criteria, modify the evaluation content based on patient needs-oriented idea, adopt scientific evaluation method to evaluate nursing quality, and scientifically and reasonably draw horizontal comparisons of nursing quality between hospitals, as well as longitudinal comparisons of a hospital’s nursing quality. These methods mentioned above can all enhance a hospital’s core competitiveness and benefit more patients. PMID:25419427

  3. Reflections on Post-Evaluation of Baccalaureate Programs: Revisiting Education Quality

    Science.gov (United States)

    Jianrong, Sun

    2009-01-01

    This paper discusses the distinction between two types of educational quality: quality at the institutional level and quality at the student learning level. The key element for continuous institutional improvement after completion of the evaluation of institutional teaching should be on redefining quality in student learning and developing a…

  4. Spring and surface water quality of the Cyprus ophiolites

    Directory of Open Access Journals (Sweden)

    C. Neal

    2002-01-01

    Full Text Available A survey of surface, spring and borehole waters associated with the ophiolite rocks of Cyprus shows five broad water types (1 Mg-HCO3, (2 Na-SO4-Cl-HCO3, (3 Na-Ca-Cl-SO4-OH-CO3, (4 Na-Cl-SO4 and (5 Ca-SO4. The waters represent a progression in chemical reactivity from surface waters that evolve within a groundwater setting due to hydrolysis of the basic/ultrabasic rock as modified by CO2-weathering. An increase in salinity is also observed which is due to mixing with a saline end-member (modified sea-water and dissolution of gypsum/anhydrite. In some cases, the waters have pH values greater than 11. Such high values are associated with low temperature serpentinisation reactions. The system is a net sink for CO2. This feature is related not only to the hydrolysis of the primary minerals in the rock, but also to CaCO3 or Ca-Mg-CO3 solubility controls. Under hyperalkaline conditions, virtually all the carbon dioxide is lost from the water due to the sufficiently high calcium levels and carbonate buffering is then insignificant. Calcium sulphate solubility controls may also be operative when calcium and sulphate concentrations are particularly high. Keywords: Cyprus, Troodos, ophiolite, serpentinisation, spring, stream, water quality, bromide, iodine, boron, trace elements, hyperalkaline.

  5. In situ anodization of aluminum surfaces studied by x-ray reflectivity and electrochemical impedance spectroscopy

    International Nuclear Information System (INIS)

    Bertram, F.; Evertsson, J.; Messing, M. E.; Mikkelsen, A.; Lundgren, E.; Zhang, F.; Pan, J.; Carlà, F.; Nilsson, J.-O.

    2014-01-01

    We present results from the anodization of an aluminum single crystal [Al(111)] and an aluminum alloy [Al 6060] studied by in situ x-ray reflectivity, in situ electrochemical impedance spectroscopy and ex situ scanning electron microscopy. For both samples, a linear increase of oxide film thickness with increasing anodization voltage was found. However, the slope is much higher in the single crystal case, and the break-up of the oxide film grown on the alloy occurs at a lower anodization potential than on the single crystal. The reasons for these observations are discussed as are the measured differences observed for x-ray reflectivity and electrochemical impedance spectroscopy.

  6. Formation of plasmonic silver nanoparticles using rapid thermal annealing at low temperature and study in reflectance reduction of Si surface

    Science.gov (United States)

    Barman, Bidyut; Dhasmana, Hrishikesh; Verma, Abhishek; Kumar, Amit; Pratap Chaudhary, Shiv; Jain, V. K.

    2017-09-01

    This work presents studies of plasmonic silver nanoparticles (AgNPs) formation at low temperatures (200 °C-300 °C) onto Si surface by sputtering followed with rapid thermal processing (RTP) for different time durations(5-30 min). The study reveals that 20 min RTP at all temperatures show minimum average size of AgNPs (60.42 nm) with corresponding reduction in reflectance of Si surface from 40.12% to mere 1.15% only in wavelength region 300-800 nm for RTP at 200 °C. A detailed supporting growth mechanism is also discussed. This low temperature technique can be helpful in achieving efficiency improvement in solar cells via reflectance reduction with additional features such as reproducibility, minimal time and very good adhesion without damaging underlying layers device parameters.

  7. Effect of surface plasmon polaritons on the sensitivity of refractive index measurement using total internal reflection method

    International Nuclear Information System (INIS)

    Roshan Entezar, S.

    2015-01-01

    The phase difference between two p-polarized and s-polarized plane waves which are reflected under total internal reflection from the base of a prism with a thin metal coating is studied. Typically such a quantity can be used to measure the refractive index of a test material using the total internal reflection method. It is shown that due to the excitation of surface plasmon polaritons at the interface between the tested dielectric material and the thin metal layer, the p-polarized light experiences a large phase shift which enlarges the phase difference between the p-polarized and the s-polarized waves. As a result, the sensitivity of refractive index measurement increases and the error in determining the refractive index decreases. - Highlights: • Phase difference of totally internally reflected p and s polarized beams is studied. • Excitation of the surface wave increases the phase shift of the p-polarized light. • The sensitivity of refractive index measurement increases by using a coated prism. • The error in determining the refractive index decreases using the coated prism

  8. Relation between seasonally detrended shortwave infrared reflectance data and land surface moisture in semi-arid Sahel

    DEFF Research Database (Denmark)

    Olsen, Jørgen Lundegaard; Ceccato, Pietro; Proud, Simon Richard

    2013-01-01

    in vegetation moisture status, and is compared to detrended time series of the Normalized Difference Vegetation Index (NDVI). It was found that when plant available water is low, the SIWSI anomalies increase over time, while the NDVI anomalies decrease over time, but less systematically. Therefore SIWSI may......In the Sudano-Sahelian areas of Africa droughts can have serious impacts on natural resources, and therefore land surface moisture is an important factor. Insufficient conventional sites for monitoring land surface moisture make the use of Earth Observation data for this purpose a key issue...... Second Generation (MSG) satellite. We focused on responses in surface reflectance to soil- and surface moisture for bare soil and early to mid- growing season. A method for implementing detrended time series of the Shortwave Infrared Water Stress Index (SIWSI) is examined for detecting variations...

  9. Determination of solid surface composition by the X-ray fluorescence method under total external reflection with angular scanning

    International Nuclear Information System (INIS)

    Krasnolutskij, V.P.

    2000-01-01

    Possibilities of determination of composition of surface layers by X-ray fluorescence analysis under total reflection of incident radiation with angular scanning of a target are investigated. For the case of the GaAs target it is shown that the sensibility of this method is sufficient for a control of element composition in layer of thickness 1 nm. A simple method for solution of inverse task of analysis of a two component medium is considered [ru

  10. Simulation of reflecting surface deviations of centimeter-band parabolic space radiotelescope (SRT) with the large-size mirror

    Science.gov (United States)

    Kotik, A.; Usyukin, V.; Vinogradov, I.; Arkhipov, M.

    2017-11-01

    he realization of astrophysical researches requires the development of high-sensitive centimeterband parabolic space radiotelescopes (SRT) with the large-size mirrors. Constructively such SRT with the mirror size more than 10 m can be realized as deployable rigid structures. Mesh-structures of such size do not provide the reflector reflecting surface accuracy which is necessary for the centimeter band observations. Now such telescope with the 10 m diameter mirror is developed in Russia in the frame of "SPECTR - R" program. External dimensions of the telescope is more than the size of existing thermo-vacuum chambers used to prove SRT reflecting surface accuracy parameters under the action of space environment factors. That's why the numerical simulation turns out to be the basis required to accept the taken designs. Such modeling should be based on experimental working of the basic constructive materials and elements of the future reflector. In the article computational modeling of reflecting surface deviations of a centimeter-band of a large-sized deployable space reflector at a stage of his orbital functioning is considered. The analysis of the factors that determines the deviations - both determined (temperatures fields) and not-determined (telescope manufacturing and installation faults; the deformations caused by features of composite materials behavior in space) is carried out. The finite-element model and complex of methods are developed. They allow to carry out computational modeling of reflecting surface deviations caused by influence of all factors and to take into account the deviations correction by space vehicle orientation system. The results of modeling for two modes of functioning (orientation at the Sun) SRT are presented.

  11. Surface segregation of InGaAs films by the evolution of reflection high-energy electron diffraction patterns

    International Nuclear Information System (INIS)

    Zhou Xun; Luo Zi-Jiang; Guo Xiang; Zhang Bi-Chan; Shang Lin-Tao; Zhou Qing; Deng Chao-Yong; Ding Zhao

    2012-01-01

    Surface segregation is studied via the evolution of reflection high-energy electron diffraction (RHEED) patterns under different values of As 4 BEP for InGaAs films. When the As 4 BEP is set to be zero, the RHEED pattern keeps a 4×3/(n × 3) structure with increasing temperature, and surface segregation takes place until 470 °C. The RHEED pattern develops into a metal-rich (4 × 2) structure as temperature increases to 495 °C. The reason for this is that surface segregation makes the In inside the InGaAs film climb to its surface. With the temperature increasing up to 515 °C, the RHEED pattern turns into a GaAs(2 × 4) structure due to In desorption. While the As 4 BEP comes up to a specific value (1.33 × 10 -4 Pa−1.33 × 10 -3 Pa), the surface temperature can delay the segregation and desorption. We find that As 4 BEP has a big influence on surface desorption, while surface segregation is more strongly dependent on temperature than surface desorption. (condensed matter: structural, mechanical, and thermal properties)

  12. Reflection of sound from finite-size plane and curved surfaces

    DEFF Research Database (Denmark)

    Rindel, Jens Holger

    2005-01-01

    of a reflector array can improve if the size of the panels is decreased. The same design frequency applies to a single reflector and a reflector array, but with different meaning; in the latter case the design frequency is the upper limit for useful reflections. This design rule was first used...

  13. Critical and Creative Reflective Inquiry: Surfacing Narratives to Enable Learning and Inform Action

    Science.gov (United States)

    Cardiff, Shaun

    2012-01-01

    Narratives are being increasingly used in nursing and action research. In this participatory action research study, nurse leaders of an acute care of the older person unit collectively, critically and creatively reflected on lived experiences in order to explore the concept of person-centred leadership within their own practice. This paper…

  14. Relationship of intertidal surface sediment chlorophyll concentration to hyper-spectral reflectance and chlorophyll fluorescence

    NARCIS (Netherlands)

    Kromkamp, J.C.; Morris, E.P.; Forster, R.M.; Honeywill, C.; Hagerthey, S.; Paterson, D.M.

    2006-01-01

    Estimating biomass of microphytobenthos (MPB) on intertidal mud flats is extremely difficult due to their patchy occurrence, especially at the scale of an entire mud flat. We tested two optical approaches that can be applied in situ: spectral reflectance and chlorophyll fluorescence. These two

  15. Reflectivity and surface roughness of multilayer-coated substrate recovery layers for EUV lithographic optics

    NARCIS (Netherlands)

    Nedelcu, I.; van de Kruijs, R.W.E.; Yakshin, A. E.; von Blanckenhagen, G.; F. Bijkerk,

    2008-01-01

    We investigated the use of separation, or substrate recovery, layers (SRLs), to enable the reuse of optical substrates after the deposition of multilayer reflective coatings, in particular Mo/Si multilayers as used for EUV lithography. An organic material (polyimide), known from other work to reduce

  16. Reflection of P and SV waves at the free surface of a monoclinic ...

    Indian Academy of Sciences (India)

    R.Narasimhan(krishtel emaging)1461 1996 Oct 15 13:05:22

    The propagation of plane waves in an anisotropic elastic medium possessing monoclinic symmetry is discussed. The expressions for ... Keywords. Anisotropic medium; elastic waves; monoclinic half-space; reflection coefficients. Proc. Indian Acad. Sci. ...... In contrast, for C < 0, the angle of reflec- tion is less than the angle of ...

  17. Quality-factor and reflection-coefficient estimation using surface-wave ghost reflections from subvertical structures

    NARCIS (Netherlands)

    Draganov, Deyan; Ruigrok, Elmer; Ghose, Ranajit; Mikesell, Dylan; van Wijk, Kasper

    Seismic interferometry can retrieve the Green's function between receivers from the cross-correlation and summation of recordings from a boundary of surrounding sources. Having the sources only along a boundary is sufficient if the medium is lossless. If the medium is dissipative, the retrieved

  18. Nonlinear reflection of a spherically divergent N-wave from a plane surface: Optical interferometry measurements in air

    International Nuclear Information System (INIS)

    Karzova, M.; Yuldashev, P.; Khokhlova, V.; Ollivier, S.; Blanc-Benon, Ph.

    2015-01-01

    Mach stem is a well-known structure typically observed in the process of strong (acoustic Mach numbers greater than 0.4) step-shock waves reflection from a rigid boundary. However, this phenomenon has been much less studied for weak shocks in nonlinear acoustic fields where Mach numbers are in the range from 0.001 to 0.01 and pressure waveforms have more complicated waveforms than step shocks. The goal of this work was to demonstrate experimentally how nonlinear reflection occurs in air for very weak spherically divergent acoustic spark-generated pulses resembling an N-wave. Measurements of reflection patterns were performed using a Mach-Zehnder interferometer. A thin laser beam with sub-millimeter cross-section was used to obtain the time resolution of 0.4 µs, which is 6 times higher than the time resolution of the condenser microphones. Pressure waveforms were reconstructed using the inverse Abel transform applied to the phase of the signal measured by the interferometer. The Mach stem formation was observed experimentally as a result of collision of the incident and reflected shock pulses. It was shown that irregular reflection of the pulse occurred in a dynamic way and the length of the Mach stem increased linearly while the pulse propagated along the surface. Since the front shock of the spark-generated pulse was steeper than the rear shock, irregular type of reflection was observed only for the front shock of the pulse while the rear shock reflection occurred in a regular regime

  19. Nonlinear reflection of a spherically divergent N-wave from a plane surface: Optical interferometry measurements in air

    Energy Technology Data Exchange (ETDEWEB)

    Karzova, M., E-mail: masha@acs366.phys.msu.ru [Laboratoire de Mécanique des Fluides et d’Acoustique, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Yuldashev, P.; Khokhlova, V. [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Ollivier, S.; Blanc-Benon, Ph. [Laboratoire de Mécanique des Fluides et d’Acoustique, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France)

    2015-10-28

    Mach stem is a well-known structure typically observed in the process of strong (acoustic Mach numbers greater than 0.4) step-shock waves reflection from a rigid boundary. However, this phenomenon has been much less studied for weak shocks in nonlinear acoustic fields where Mach numbers are in the range from 0.001 to 0.01 and pressure waveforms have more complicated waveforms than step shocks. The goal of this work was to demonstrate experimentally how nonlinear reflection occurs in air for very weak spherically divergent acoustic spark-generated pulses resembling an N-wave. Measurements of reflection patterns were performed using a Mach-Zehnder interferometer. A thin laser beam with sub-millimeter cross-section was used to obtain the time resolution of 0.4 µs, which is 6 times higher than the time resolution of the condenser microphones. Pressure waveforms were reconstructed using the inverse Abel transform applied to the phase of the signal measured by the interferometer. The Mach stem formation was observed experimentally as a result of collision of the incident and reflected shock pulses. It was shown that irregular reflection of the pulse occurred in a dynamic way and the length of the Mach stem increased linearly while the pulse propagated along the surface. Since the front shock of the spark-generated pulse was steeper than the rear shock, irregular type of reflection was observed only for the front shock of the pulse while the rear shock reflection occurred in a regular regime.

  20. An assessment of thin cloud detection by applying bidirectional reflectance distribution function model-based background surface reflectance using Geostationary Ocean Color Imager (GOCI): A case study for South Korea

    Science.gov (United States)

    Kim, Hye-Won; Yeom, Jong-Min; Shin, Daegeun; Choi, Sungwon; Han, Kyung-Soo; Roujean, Jean-Louis

    2017-08-01

    In this study, a new assessment of thin cloud detection with the application of bidirectional reflectance distribution function (BRDF) model-based background surface reflectance was undertaken by interpreting surface spectra characterized using the Geostationary Ocean Color Imager (GOCI) over a land surface area. Unlike cloud detection over the ocean, the detection of cloud over land surfaces is difficult due to the complicated surface scattering characteristics, which vary among land surface types. Furthermore, in the case of thin clouds, in which the surface and cloud radiation are mixed, it is difficult to detect the clouds in both land and atmospheric fields. Therefore, to interpret background surface reflectance, especially underneath cloud, the semiempirical BRDF model was used to simulate surface reflectance by reflecting solar angle-dependent geostationary sensor geometry. For quantitative validation, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data were used to make a comparison with the proposed cloud masking result. As a result, the new cloud masking scheme resulted in a high probability of detection (POD = 0.82) compared with the Moderate Resolution Imaging Spectroradiometer (MODIS) (POD = 0.808) for all cloud cases. In particular, the agreement between the CALIPSO cloud product and new GOCI cloud mask was over 94% when detecting thin cloud (e.g., altostratus and cirrus) from January 2014 to June 2015. This result is relatively high in comparison with the result from the MODIS Collection 6 cloud mask product (MYD35).

  1. Temporal variations of surface water quality in urban, suburban and rural areas during rapid urbanization in Shanghai, China

    International Nuclear Information System (INIS)

    Wang Junying; Da Liangjun; Song Kun; Li Bailian

    2008-01-01

    As the economic and financial center of China, Shanghai has experienced an extensive urban expansion since the early 1980s, with an attendant cost in environmental degradation. We use an integrated pollution index to study the temporal variations of surface water quality in urban, suburban and rural areas between 1982 and 2005. Data on monitored cross-sections were collected from the Shanghai Environmental Monitoring Center. The results indicated that the spatial pattern of surface water quality was determined by the level of urbanization. Surface water qualities in urban and suburban areas were improved by strengthening the environmental policies and management, but were worsening in rural areas. The relationship between economic growth and surface water quality in Shanghai showed an inversed-U-shaped curve, which reflected a similar pattern in most developed countries. This research suggests that decision makers and city officials should be more aware of the recent pollution increases in Shanghai. - An integrated pollution index documents the deterioration of water quality in greater Shanghai, recently most serious in rural sections

  2. Study of Surface Wettability Change of Unconsolidated Sand Using Diffuse Reflectance Infrared Fourier Transform Spectroscopy and Thermogravimetric Analysis.

    Science.gov (United States)

    Gómora-Herrera, Diana; Navarrete Bolaños, Juan; Lijanova, Irina V; Olivares-Xometl, Octavio; Likhanova, Natalya V

    2018-04-01

    The effects exerted by the adsorption of vapors of a non-polar compound (deuterated benzene) and a polar compound (water) on the surface of Ottawa sand and a sample of reservoir sand (Channel), which was previously impregnated with silicon oil or two kinds of surfactants, (2-hydroxyethyl) trimethylammonium oleate (HETAO) and (2-hydroxyethyl)trimethylammonium azelate (HETAA), were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and thermogravimetric analysis (TGA). The surface chemistry of the sandstone rocks was elucidated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX). Terminal surface groups such as hydroxyls can strongly adsorb molecules that interact with these surface groups (surfactants), resulting in a wettability change. The wettability change effect suffered by the surface after treating it with surfactants was possible to be detected by the DRIFTS technique, wherein it was observed that the surface became more hydrophobic after being treated with silicon oil and HETAO; the surface became more hydrophilic after treating it with HETAA.

  3. Porous Nanomaterials for Ultrabroadband Omnidirectional Anti-Reflection Surfaces with Applications in High Concentration Photovoltaics

    KAUST Repository

    Yao, Yuan

    2016-12-06

    Materials for nanoporous coatings that exploit optimized chemistries and self-assembly processes offer capabilities to reach ≈98% transmission efficiency and negligible scattering losses over the broad wavelength range of the solar spectrum from 350 nm to 1.5 μm, on both flat and curved glass substrates. These nanomaterial anti-reflection coatings also offer wide acceptance angles, up to ±40°, for both s- and p-polarization states of incident light. Carefully controlled bilayer films have allowed for the fabrication of dual-sided, gradient index profiles on plano-convex lens elements. In concentration photovoltaics platforms, the resultant enhancements in the photovoltaics efficiencies are ≈8%, as defined by experimental measurements on systems that use microscale triple-junction solar cells. These materials and their applications in technologies that require control over interface reflections have the potential for broad utility in imaging systems, photolithography, light-emitting diodes, and display technologies.

  4. Secondary electron/reflected particle coincidence studies during slow highly charged ion-surface interactions

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, C.T.; Szilagyi, Z.; Shah, M.B.; McCullough, R.W. [Queen' s Univ., Belfast, Northern Ireland (United Kingdom); Woolsey, J.M. [Stirling Univ. (United Kingdom). DBMS; Trassl, R.; Salzborn, E. [Giessen Univ. (Germany). Inst. fuer Kernphysik

    2001-07-01

    We have measured the secondary electron emission statistics (ES) for 5 keV N{sup q+} (q = 1-4) ions incident at 10 on polycrystalline aluminium, in coincidence with specularly reflected N{sup 0}. In this arrangement the kinetic contribution to secondary electron emission is minimised. The experimental data shows that the coincident electron yield, {gamma}, increases linearly with incident ion charge state. The kinetic emission contribution has also been determined from this data. The ES due to 2 and 4 keV He{sup 2+} impact on polycrystalline aluminium in coincidence with specularly reflected He{sup +} and He{sup 0} have also been determined. The process He{sup 2+} {yields} He{sup 0} yields a larger {gamma} value than the process He{sup 2+} {yields} He{sup +}. (orig.)

  5. Characterizing the surface heterogeneity of fire effects using multi-temporal reflective wavelength data

    CSIR Research Space (South Africa)

    Roy, DP

    2005-10-10

    Full Text Available fires lit in South Africa to substantiate and illustrate the model findings. We discuss the implications of our findings for algorithms that examine change in reflectance to map fire-affected areas and discuss the possibility of deriving cc and f from... measurements were taken in the laboratory to reduce field measurement errors and because we were concerned only with obtaining representative spectra for illustrative modelling. SAFARI 2000 4203 The measurements were made under diffuse illumination conditions...

  6. Virtual Relighting of a Virtualized Scene by Estimating Surface Reflectance Properties

    OpenAIRE

    福富, 弘敦; 町田, 貴史; 横矢, 直和

    2011-01-01

    In mixed reality that merges real and virtual worlds, it is required to interactively manipulate the illumination conditions in a virtualized space. In general, specular reflections in a scene make it difficult to interactively manipulate the illumination conditions. Our goal is to provide an opportunity to simulate the original scene, including diffuse and specular relfections, with novel viewpoints and illumination conditions. Thus, we propose a new method for estimating diffuse and specula...

  7. Role of the substrate reflectance and surface-bulk treatments in CsI quantum efficiency

    CERN Document Server

    Singh, B K; Nitti, M A; Valentini, A

    2003-01-01

    We have experimentally investigated the following aspects related to the quantum efficiency of CsI photocathodes: the type of substrate, the film thickness and the effect of a 'bulk treatment' during the film growth. We discovered that, using a high reflectivity aluminium substrate, the photoemission of very thin CsI film is enhanced. Our study also revealed that photocathodes become less sensitive to moisture when a negative bias voltage is applied to the substrate during the film deposition process.

  8. Quality assessment of terahertz time-domain spectroscopy transmission and reflection modes for graphene conductivity mapping

    DEFF Research Database (Denmark)

    Mackenzie, David M.A.; Whelan, Patrick Rebsdorf; Bøggild, Peter

    2018-01-01

    We present a comparative study of electrical measurements of graphene using terahertz time-domain spectroscopy in transmission and reflection mode, and compare the measured sheet conductivity values to electrical van der Pauw measurements made independently in three different laboratories. Overall......, while offering the additional advantages associated with contactless mapping, such as high throughput, no lithography requirement, and with the spatial mapping directly revealing the presence of any inhomogeneities or isolating defects. The confirmation of the accuracy of reflection-mode removes...

  9. 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.

  10. On quantum motion of particle in linear potential bounded by perfectly reflecting plane and parabolic surfaces

    International Nuclear Information System (INIS)

    Pokotilovskij, Yu.N.

    1999-01-01

    The motion of a particle in the linear potential bounded by an inclined plane or parabolic surfaces is considered. The quantization of energy and wave functions is obtained numerically by the separation of the variables method

  11. Classification of reflected signals from cavitated tooth surfaces using an artificial intelligence technique incorporating a fiber optic displacement sensor

    Science.gov (United States)

    Rahman, Husna Abdul; Harun, Sulaiman Wadi; Arof, Hamzah; Irawati, Ninik; Musirin, Ismail; Ibrahim, Fatimah; Ahmad, Harith

    2014-05-01

    An enhanced dental cavity diameter measurement mechanism using an intensity-modulated fiber optic displacement sensor (FODS) scanning and imaging system, fuzzy logic as well as a single-layer perceptron (SLP) neural network, is presented. The SLP network was employed for the classification of the reflected signals, which were obtained from the surfaces of teeth samples and captured using FODS. Two features were used for the classification of the reflected signals with one of them being the output of a fuzzy logic. The test results showed that the combined fuzzy logic and SLP network methodology contributed to a 100% classification accuracy of the network. The high-classification accuracy significantly demonstrates the suitability of the proposed features and classification using SLP networks for classifying the reflected signals from teeth surfaces, enabling the sensor to accurately measure small diameters of tooth cavity of up to 0.6 mm. The method remains simple enough to allow its easy integration in existing dental restoration support systems.

  12. Reflection on Quality Assurance System of Higher Vocational Education under Big Data Era

    Directory of Open Access Journals (Sweden)

    Jiang Xinlan

    2015-01-01

    Full Text Available Big data has the features like Volume, Variety, Value and Velocity. Here come the new opportunities and challenges for construction of Chinese quality assurance system of higher vocational education under big data era. There are problems in current quality assurance system of higher vocational education, such as imperfect main body, non-formation of internally and externally incorporated quality assurance system, non-scientific security standard and insufficiency in security investment. The construction of higher vocational education under big data era requires a change in the idea of quality assurance system construction to realize the multiple main bodies and multiple layers development trend for educational quality assurance system, and strengthen the construction of information platform for quality assurance system.

  13. Geometrical error calibration in reflective surface testing based on reverse Hartmann test

    Science.gov (United States)

    Gong, Zhidong; Wang, Daodang; Xu, Ping; Wang, Chao; Liang, Rongguang; Kong, Ming; Zhao, Jun; Mo, Linhai; Mo, Shuhui

    2017-08-01

    In the fringe-illumination deflectometry based on reverse-Hartmann-test configuration, ray tracing of the modeled testing system is performed to reconstruct the test surface error. Careful calibration of system geometry is required to achieve high testing accuracy. To realize the high-precision surface testing with reverse Hartmann test, a computer-aided geometrical error calibration method is proposed. The aberrations corresponding to various geometrical errors are studied. With the aberration weights for various geometrical errors, the computer-aided optimization of system geometry with iterative ray tracing is carried out to calibration the geometrical error, and the accuracy in the order of subnanometer is achieved.

  14. 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.

  15. Reflection-based fibre-optic refractive index sensor using surface plasmon resonance

    Czech Academy of Sciences Publication Activity Database

    Hlubina, P.; Kadulová, M.; Ciprian, D.; Sobota, Jaroslav

    2014-01-01

    Roč. 9, August 19 (2014), 14033:1-5 ISSN 1990-2573 R&D Projects: GA MŠk(CZ) LO1212 Keywords : surface plasmon resonance * fibre-optic sensor * spectral interrogation technique * aqueous solutions of ethanol * refractive index Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.231, year: 2014

  16. Processing OMEGA/Mars Express hyperspectral imagery from radiance-at-sensor to surface reflectance

    NARCIS (Netherlands)

    Bakker, W.H.; Ruitenbeek, F.J.A. van; Werff, H.M.A. van der; Zegers, T.E.; Oosthoek, J.H.P.; Marsh, S.H.; Meer, F.D. van der

    2014-01-01

    OMEGA/Mars Express hyperspectral imagery is an excellent source of data for exploring the surface composition of the planet Mars. Compared to terrestrial hyperspectral imagery, the data are challenging to work with; scene-specific transmission models are lacking, spectral features are shallow making

  17. RESEARCH OF THE ENTRANCE ANGLE EFFECT ON THE REFLECTANCE SPECTRA OF THE STAINLESS STEEL SURFACE OXIDIZED BY PULSED LASER RADIATION

    Directory of Open Access Journals (Sweden)

    V. P. Veiko

    2016-05-01

    Full Text Available Subject of Research.Oxide films on the metal surfaces can be obtained both by surface-uniform infrared heating and local laser treatment e.g. by sequence of nanosecond laser pulses. Due to interference in created films the coloration of treated area is observed. The present work shows the results of spectrophotometric measurements for various light entrance angles in the range of 10-60°. Method. AISI 304 stainless steel plates were oxidized by two methods: in muffle furnace FM - 10 (Т= 500-600° С, t = 5-7 min. and at line-by-line scanning by sequence of nanosecond laser pulses (λ = 1.06 μm, τ =100 ns, r = 25 μm,q=2.91∙107 W/cm2, Nx = 30, Ny = 1. Surface research in optical resolution was realized by Carl Zeiss Axio Imager A1M. Reflectance spectra were obtained with spectrophotometer Lambda Perkin 1050 with integrating sphere at different fixed light incidence angles. Topographic features were detected by scanning probe microscopy investigation with NanoEducator equipment. Main Results. The quantitative surface geometry characteristics of AISI 304 stainless steel patterns treated by different methods are obtained. It was found that the increase of light entrance angle has no influence on the form of reflection coefficient dependence from a wavelength, but a blue-shift occurs especially for the case of laser treatment. This difference can be caused by surface topology formed by laser heating and variety of oxide film thickness. This effect results in more significant change in observed sample color for laser treatment then for infrared heating. Practical Relevance. The results obtained in the present work can be used to implement a new element of product protection against forgery with the product marking.

  18. Quality assurance of data: ensuring that numbers reflect operational definitions and contain real measurements

    DEFF Research Database (Denmark)

    Rieder, H L; Lauritsen, Jens

    2011-01-01

    Any analysis is only as convincing as the quality of the underlying data. In this article, the role of data quality is exemplified by its impact on the interpretation of surveillance data, by operations research projects conducted in the training courses of the International Union Against Tubercu...... and physical barriers to double-entry are reduced....

  19. Higher Education Quality in Kenya: A Critical Reflection of Key Challenges

    Science.gov (United States)

    Odhiambo, George O.

    2011-01-01

    This article examines the unique challenges facing Kenya's public higher education institutions. It explores the struggle to develop quality and quality assurance mechanisms against a background of rapidly diminishing income, brain drain, political interference and the negative aspects of globalisation. The challenges have consequently led to a…

  20. Sea Surface Height, Absolute, Aviso, 0.25 degrees, Global, Science Quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Aviso Absolute Sea Surface Height is the Sea Surface Height Deviation plus the long term mean dynamic height. This is Science Quality data.

  1. An Instructional Model for Guiding Reflection and Research in the Classroom: The Educational Situation Quality Model

    Science.gov (United States)

    Domenech-Betoret, Fernando

    2013-01-01

    The purpose of this work is to present an instructional model entitled the "Modelo de Calidad de Situacion Educativa" (MCSE) and how teachers can use it to reflect and investigate in a formal educational setting. It is a theoretical framework which treat to explain the functioning of an educational setting by organizing and relating the…

  2. Measurements of plasma mirror reflectivity and focal spot quality for tens of picosecond laser pulses

    Science.gov (United States)

    Forestier-Colleoni, Pierre; Williams, Jackson; Scott, Graeme; Mariscal, Dereck. A.; McGuffey, Christopher; Beg, Farhat N.; Chen, Hui; Neely, David; Ma, Tammy

    2017-10-01

    The Advanced Radiographic Capability (ARC) laser at the NIF (LLNL) is high-energy ( 4 kJ) with a pulse length of 30ps, and is capable of focusing to an intensity of 1018W/cm2 with a 100 μm focal spot. The ARC laser is at an intensity which can be used to produce proton beams. However, for applications such as radiography and warm dense matter creation, a higher laser intensity may be desired to generate more energetic proton beams. One possibility to increase the intensity is to decrease the focused spot size by employing a smaller f-number optic. But it is difficult to implement such an optic or to bring the final focusing parabola closer to the target within the complicated NIF chamber geometry. A proposal is to use ellipsoidal plasma mirrors (PM) for fast focusing of the ARC laser light, thereby increasing the peak intensity. There is uncertainty, however, in the survivability and reflectivity of PM at such long pulse durations. Here, we show experimental results from the Titan laser to study the reflectivity of flat PM as a function of laser pulse length. A calorimeter was used to measure the PM reflectivity. We also observed degradation of the far and near field energy distribution of the laser after the reflection by the PM for pulse-lengths beyond 10ps. Contract DE-AC52-07NA27344. Funded by the LLNL LDRD program: tracking code 17-ERD-039.

  3. Red-Edge Spectral Reflectance as an Indicator of Surface Moisture Content in an Alaskan Peatland Ecosystem

    Science.gov (United States)

    McPartland, M.; Kane, E. S.; Turetsky, M. R.; Douglass, T.; Falkowski, M. J.; Montgomery, R.; Edwards, J.

    2015-12-01

    Arctic and boreal peatlands serve as major reservoirs of terrestrial organic carbon (C) because Net Primary Productivity (NPP) outstrips C loss from decomposition over long periods of time. Peatland productivity varies as a function of water table position and surface moisture content, making C storage in these systems particularly vulnerable to the climate warming and drying predicted for high latitudes. Detailed spatial knowledge of how aboveground vegetation communities respond to changes in hydrology would allow for ecosystem response to environmental change to be measured at the landscape scale. This study leverages remotely sensed data along with field measurements taken at the Alaska Peatland Experiment (APEX) at the Bonanza Creek Long Term Ecological Research site to examine relationships between plant solar reflectance and surface moisture. APEX is a decade-long experiment investigating the effects of hydrologic change on peatland ecosystems using water table manipulation treatments (raised, lowered, and control). Water table levels were manipulated throughout the 2015 growing season, resulting in a maximum separation of 35 cm between raised and lowered treatment plots. Water table position, soil moisture content, depth to seasonal ice, soil temperature, photosynthetically active radiation (PAR), CO2 and CH4 fluxes were measured as predictors of C loss through decomposition and NPP. Vegetation was surveyed for percent cover of plant functional types. Remote sensing data was collected during peak growing season, when the separation between treatment plots was at maximum difference. Imagery was acquired via a SenseFly eBee airborne platform equipped with a Canon S110 red-edge camera capable of detecting spectral reflectance from plant tissue at 715 nm band center to within centimeters of spatial resolution. Here, we investigate empirical relationships between spectral reflectance, water table position, and surface moisture in relation to peat carbon balance.

  4. Quantitative surface topography determination by Nomarski reflection microscopy. 2: Microscope modification, calibration, and planar sample experiments

    International Nuclear Information System (INIS)

    Hartman, J.S.; Gordon, R.L.; Lessor, D.L.

    1980-01-01

    The application of reflective Nomarski differential interference contrast microscopy for the determination of quantitative sample topography data is presented. The discussion includes a review of key theoretical results presented previously plus the experimental implementation of the concepts using a commercial Momarski microscope. The experimental work included the modification and characterization of a commercial microscope to allow its use for obtaining quantitative sample topography data. System usage for the measurement of slopes on flat planar samples is also discussed. The discussion has been designed to provide the theoretical basis, a physical insight, and a cookbook procedure for implementation to allow these results to be of value to both those interested in the microscope theory and its practical usage in the metallography laboratory

  5. In Situ Nondestructive Analysis of Kalanchoe pinnata Leaf Surface Structure by Polarization-Modulation Infrared Reflection-Absorption Spectroscopy.

    Science.gov (United States)

    Hama, Tetsuya; Kouchi, Akira; Watanabe, Naoki; Enami, Shinichi; Shimoaka, Takafumi; Hasegawa, Takeshi

    2017-12-14

    The outermost surface of the leaves of land plants is covered with a lipid membrane called the cuticle that protects against various stress factors. Probing the molecular-level structure of the intact cuticle is highly desirable for understanding its multifunctional properties. We report the in situ characterization of the surface structure of Kalanchoe pinnata leaves using polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS). Without sample pretreatment, PM-IRRAS measures the IR spectra of the leaf cuticle of a potted K. pinnata plant. The peak position of the CH 2 -related modes shows that the cuticular waxes on the leaf surface are mainly crystalline, and the alkyl chains are highly packed in an all-trans zigzag conformation. The surface selection rule of PM-IRRAS revealed the average orientation of the cuticular molecules, as indicated by the positive and negative signals of the IR peaks. This unique property of PM-IRRAS revealed that the alkyl chains of the waxes and the main chains of polysaccharides are oriented almost perpendicular to the leaf surface. The nondestructive, background-free, and environmental gas-free nature of PM-IRRAS allows the structure and chemistry of the leaf cuticle to be studied directly in its native environment.

  6. Identification of hydrogen and deuterium at the surface of water ice by reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Yubero, F.; Toekesi, K.

    2009-01-01

    Complete text of publication follows. The study of elastically backscattered electrons from surfaces by reflection electron energy loss spectroscopy (REELS) has been recently recommended as an alternative technique to quantify the H content at the surface of a-C:H and polymer samples. This analysis is based on the fact that the energy loss of the incident electrons due to the recoil effect depends on the atomic mass of the particular atom present at the surface. The observed difference in recoil energies between H and O atoms (about 2 eV for 1.5 keV primary electrons) can be easily measured with standard electron spectrometers used in surface analysis. In this paper we go one step forward to explore if, with the same experimental approach, it is possible to differentiate between hydrogen and deuterium (D) in the surface region of a sample. This capability could be important for technological fields such as surface functionalization, where it is desired to distinguish between H and D at surfaces after interaction with labeled compounds. We have chosen normal and deuterated water as test labeled compounds because this polar molecule is of key importance in numerous surface reactions. It has been shown that H and D can be easily distinguished at the surface of water ice [4] using standard REELS measurements with 1000 - 1650 eV primary-electron energies, i.e., a surface analytical technique. Differences in recoil energies of the O - H and O - D atom pairs present in H 2 O and D 2 O have been found to agree with MC simulations (see Fig.1). There are many possible applications of H and D detection by REELS. Among many others, this study opens the possibility of nondestructive studies of deuterium-labeled atoms present or adsorbed on surfaces. For example, studies of H incorporation into a polymer or carbonbased surface after plasma activation with gas mixtures with several labeled molecules containing H atoms. Acknowledgements F.Y. thanks the Spanish Ministry of Science

  7. A small-displacement sensor using total internal reflection theory and surface plasmon resonance technology for heterodyne interferometry.

    Science.gov (United States)

    Wang, Shinn-Fwu

    2009-01-01

    A small-displacement sensor based on total-internal reflection theory and surface plasmon resonance technology is proposed for use in heterodyne interferometry. A small displacement can be obtained simply by measuring the variation in phase difference between s- and p-polarization states with the small-displacement sensor. The theoretical displacement resolution of the small-displacement sensor can reach 0.45 nm. The sensor has some additional advantages, e.g., a simple optical setup, high resolution, high sensitivity and rapid measurement. Its feasibility is also demonstrated.

  8. Modeling Bidirectional Reflectance Distribution Function of One-dimensional Random Rough Surfaces with the Finite Difference Time Domain Method

    Directory of Open Access Journals (Sweden)

    Min-Jhong Gu

    2014-08-01

    Full Text Available This article describes the development of a suite of programs that is capable of simulating the radiation properties of a random rough surface (RRS. The fundamental approach involves the generation, by fast Fourier transform (FFT built with rigorous finite difference time domain (FDTD, as the theoretical basis for the simulation of a bidirectional reflectance distribution function (BRDF of the RRS. The results are compared with the measurements and modeling of existing work to verify the feasibility of customized programming. It was found that the results of this study were a better match to the measurement data than those achieved in other modeling work.

  9. A Generic Approach for Inversion of Surface Reflectance over Land: Overview, Application and Validation Using MODIS and LANDSAT8 Data

    Science.gov (United States)

    Vermote, E.; Roger, J. C.; Justice, C. O.; Franch, B.; Claverie, M.

    2016-01-01

    This paper presents a generic approach developed to derive surface reflectance over land from a variety of sensors. This technique builds on the extensive dataset acquired by the Terra platform by combining MODIS and MISR to derive an explicit and dynamic map of band ratio's between blue and red channels and is a refinement of the operational approach used for MODIS and LANDSAT over the past 15 years. We will present the generic approach and the application to MODIS and LANDSAT data and its validation using the AERONET data.

  10. Crystals with an Open Wave-Vector Surface: Peculiarities of Reflection and Possibilities of Designing Flat Lenses

    International Nuclear Information System (INIS)

    Eritsyan, O. S.; Lalayan, A. A.; Arakelyan, O. M.; Papoyan, A. A.; Kostanyan, R. B.

    2010-01-01

    The frequency dependence of the reflection coefficient of MgF 2 crystal in the frequency range of 200-800 cm -1 at different orientations of the optical axis has been investigated. The experimental data are compared with the calculation results. This comparison confirms that the wave vectors for the extraordinary wave have an open surface. This makes it possible to focus a divergent beam refracted at a flat boundary ori- ented perpendicularly to the optical crystal axis. The focusing effect of a plane-parallel MgF 2 crystal plate is calculated.

  11. Effect of finishing process on the surface quality of Co-Cr-Mo dental alloys

    Directory of Open Access Journals (Sweden)

    Dorota Klimecka -Tatar

    2016-09-01

    Full Text Available Preparatory procedures for the material have a significant influence on the surface stereometry of the material. This study investigated the effect of the electropolishing process on the surface quality of metallic prosthetic constructions based on Co-Cr-Mo alloys. It has been found that the process of electropolishing prevents to excessive development of the surface of a material and consequently improves surface quality.

  12. Spatial and energy distributions of satellite-speed helium atoms reflected from satellite-type surfaces

    International Nuclear Information System (INIS)

    Liu, S.M.; Rodgers, W.E.; Knuth, E.L.

    1977-01-01

    Interactions of satellite-speed helium atoms (accelerated in an expansion from an arc-heated supersonic-molecular-beam source) with practical satellite surfaces have been investigated experimentally. The density and energy distributions of the scattered atoms were measured using a detection system developed for this study. This detection system includes (a) a target positioning mechanism, (b) a detector rotating mechanism, and (c) a mass spectrometer and/or a retarding-field energy analyzer. (Auth.)

  13. Analysis and experimental investigation for collimator reflective mirror surface deformation adjustment

    Directory of Open Access Journals (Sweden)

    Chia-Yen Chan

    2017-01-01

    Full Text Available Collimator design is essential for meeting the requirements of high-precision telescopes. The collimator diameter should be larger than that of the target for alignment. Special supporting structures are required to reduce the gravitational deformation and control the surface deformation induced by the mounting force when inspecting large-aperture primary mirrors (M1. A ZERODURÂŽ mirror 620 mm in diameter for a collimator was analyzed using the finite element method to obtain the deformation induced by the supporting structures and adjustment mechanism. Zernike polynomials were also adopted to fit the optical surface and separate corresponding aberrations. The computed and measured wavefront aberration configurations for the collimator M1 were obtained complementally. The wavefront aberrations were adjusted using fine adjustment screws using 3D optical path differences map of the mirror surface. Through studies using different boundary conditions and inner ring support positions, it is concluded that the optical performance was excellent under a strong enough supporter. The best adjustment position was attained and applied to the actual collimator M1 to prove the correctness of the simulation results.

  14. Segmentation of 3D ultrasound computer tomography reflection images using edge detection and surface fitting

    Science.gov (United States)

    Hopp, T.; Zapf, M.; Ruiter, N. V.

    2014-03-01

    An essential processing step for comparison of Ultrasound Computer Tomography images to other modalities, as well as for the use in further image processing, is to segment the breast from the background. In this work we present a (semi-) automated 3D segmentation method which is based on the detection of the breast boundary in coronal slice images and a subsequent surface fitting. The method was evaluated using a software phantom and in-vivo data. The fully automatically processed phantom results showed that a segmentation of approx. 10% of the slices of a dataset is sufficient to recover the overall breast shape. Application to 16 in-vivo datasets was performed successfully using semi-automated processing, i.e. using a graphical user interface for manual corrections of the automated breast boundary detection. The processing time for the segmentation of an in-vivo dataset could be significantly reduced by a factor of four compared to a fully manual segmentation. Comparison to manually segmented images identified a smoother surface for the semi-automated segmentation with an average of 11% of differing voxels and an average surface deviation of 2mm. Limitations of the edge detection may be overcome by future updates of the KIT USCT system, allowing a fully-automated usage of our segmentation approach.

  15. On fatigue crack growth mechanisms of MMC: Reflection on analysis of 'multi surface initiations'

    International Nuclear Information System (INIS)

    Mkaddem, A.; El Mansori, M.

    2009-01-01

    This work attempts to examine the mechanisms of fatigue when cracks synergetically initiate in more than one site at the specimen surface. The metal matrix composites (MMC) i.e. silicon carbide particles reinforced aluminium matrix composites (Al/SiC p -MMC), seem to be good candidates to accelerate fatigue failures following multi surface initiations (MSI). Closure effects of MSI mechanisms on the variation of fatigue behaviour are explored for various stress states. Experiments were carried out using non pre-treated and pre-treated specimens. Using an Equivalent Ellipse Method (EEM), it is shown that the aspect of surface finish of specimen plays an important role on crack growth. Scanning Electron Microscope (SEM) inspections have lead to distinguishing the initiation regions from propagation regions and final separation regions. It is also revealed that the total lifetime of specimens is sensitive to heat treatment. Moreover, it is found that the appearance of MSI in cycled materials is more probable at high level of fatigue loads.

  16. 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.

  17. Potential Long-Term Records of Surface Albedo at Fine Spatiotemporal Resolution from Landsat/Sentinle-2A Surface Reflectance and MODIS/VIIRS BRDF

    Science.gov (United States)

    Li, Z.; Schaaf, C.; Shuai, Y.; Liu, Y.; Sun, Q.; Erb, A.; Wang, Z.

    2016-12-01

    The land surface albedo products at fine spatial resolutions are generated by coupling surface reflectance (SR) from Landsat (30 m) or Sentinel-2A (20 m) with concurrent surface anisotropy information (the Bidirectional Reflectance Distribution Function - BRDF) at coarser spatial resolutions from sequential multi-angular observations by the Moderate Resolution Imaging Spectroradiometer (MODIS) or its successor, the Visible Infrared Imaging Radiometer Suite (VIIRS). We assess the comparability of four types of fine-resolution albedo products (black-sky and white-sky albedos over the shortwave broad band) generated by coupling, (1) Landsat-8 Optical Land Imager (OLI) SR with MODIS BRDF; (2) OLI SR with VIIRS BRDF; (3) Sentinel-2A MultiSpectral Instrument (MSI) SR with MODIS BRDF; and (4) MSI SR with VIIRS BRDF. We evaluate the accuracy of these four types of fine-resolution albedo products using ground tower measurements of surface albedo over six SURFace RADiation Network (SURFRAD) sites in the United States. For comparison with the ground measurements, we estimate the actual (blue-sky) albedo values at the six sites by using the satellite-based retrievals of black-sky and white-sky albedos and taking into account the proportion of direct and diffuse solar radiation from the ground measurements at the sites. The coupling of the OLI and MSI SR with MODIS BRDF has already been shown to provide accurate fine-resolution albedo values. With demonstration of a high agreement in BRDF products from MODIS and VIIRS, we expect to see consistency between all four types of fine-resolution albedo products. This assurance of consistency between the couplings of both OLI and MSI with both MODIS and VIIRS guarantees the production of long-term records of surface albedo at fine spatial resolutions and an increased temporal resolution. Such products will be critical in studying land surface changes and associated surface energy balance over the dynamic and heterogeneous landscapes

  18. An experimental investigation of the reflection of low energy electrons from surfaces of 2H-MoS2

    International Nuclear Information System (INIS)

    Komolov, S.A.; Chadderton, L.T.

    1978-01-01

    Experiments are described in which a new technique - total current spectroscopy (TCS) - has been used to investigate the energy dependence of the reflection of low energy electrons from clean surfaces of the naturally occuring mineral molybdenite (2H-MoS 2 ). A theory involving both elastic and inelastic scattering of electrons is applied to a band structure calculated for molybdenite by Mattheiss. With relatively few approximations the results of numerical calculations for a TCS spectrum from molybdenite agree surprisingly well with experiment. It is suggested that TCS will prove to be a convenient and sensitive tool for the probing of energy structures in other solid surfaces. For the transition metal dichalcogenide series it should be possible to observe systematic changes in TCS spectra associated with changes in band structure, and subsequently to predict details in the density of states distributions using iterative computer procedures. (Auth.)

  19. Surface topography to reflectivity mapping in two-dimensional photonic crystals designed in germanium

    Energy Technology Data Exchange (ETDEWEB)

    Husanu, M.A.; Ganea, C.P. [National Institute of Materials Physics, Atomistilor 105b, 077125 Magurele, Ilfov (Romania); Anghel, I. [National Institute for Laser, Plasma & Radiation Physics, Atomistilor 409, 077125 Magurele (Romania); University of Bucharest, Faculty of Physics, Atomistilor 405, 077125 Magurele (Romania); Florica, C.; Rasoga, O. [National Institute of Materials Physics, Atomistilor 105b, 077125 Magurele, Ilfov (Romania); Popescu, D.G., E-mail: dana.popescu@infim.ro [National Institute of Materials Physics, Atomistilor 105b, 077125 Magurele, Ilfov (Romania)

    2015-11-15

    Highlights: • Laser ablation is used for drilling a periodic 2D photonic structure. • Confinement of radiation is revealed by infra-red spectromicroscopy correlated with numerical calculations. • Telecommunication range is accessible upon tuning conveniently the processing parameters. - Abstract: Light confinement in a two dimensional photonic crystal (2D PhC) with hexagonal symmetry is studied using infra-red reflectance spectromicroscopy and numerical calculations. The structure has been realized by laser ablation, using a pulsed laser (λ = 775 nm), perforating an In-doped Ge wafer and creating a lattice of holes with well-defined symmetry. Correlating the spectral signature of the photonic gaps recorded experimentally with the results obtained in the finite difference time domain and finite difference frequency domain calculations, we established the relationship between the geometric parameters of the structure (lattice constants, shape of the hole) and its efficiency in trapping and guiding the radiation in a well-defined frequency range. Besides the gap in the low energy range of transversal electric modes, a second one is identified in the telecommunication range, originating in the localization of the leaky modes within the radiation continuum. The emerging picture is of a device with promising characteristics as an alternative to Si-based technology in photonic device fabrication with special emphasize in energy storage and conversion.

  20. Experimental Study in Taguchi Method on Surface Quality Predication of HSM

    Science.gov (United States)

    Ji, Yan; Li, Yueen

    2018-05-01

    Based on the study of ball milling mechanism and machining surface formation mechanism, the formation of high speed ball-end milling surface is a time-varying and cumulative Thermos-mechanical coupling process. The nature of this problem is that the uneven stress field and temperature field affect the machined surface Process, the performance of the processing parameters in the processing interaction in the elastic-plastic materials produced by the elastic recovery and plastic deformation. The surface quality of machining surface is characterized by multivariable nonlinear system. It is still an indispensable and effective method to study the surface quality of high speed ball milling by experiments.

  1. Novel anti-reflection technology for GaAs single-junction solar cells using surface patterning and Au nanoparticles.

    Science.gov (United States)

    Kim, Youngjo; Lam, Nguyen Dinh; Kim, Kangho; Kim, Sangin; Rotermund, Fabian; Lim, Hanjo; Lee, Jaejin

    2012-07-01

    Single-junction GaAs solar cell structures were grown by low-pressure MOCVD on GaAs (100) substrates. Micro-rod arrays with diameters of 2 microm, 5 microm, and 10 microm were fabricated on the surfaces of the GaAs solar cells via photolithography and wet chemical etching. The patterned surfaces were coated with Au nanoparticles using an Au colloidal solution. Characteristics of the GaAs solar cells with and without the micro-rod arrays and Au nanoparticles were investigated. The short-circuit current density of the GaAs solar cell with 2 microm rod arrays and Au nanoparticles increased up to 34.9% compared to that of the reference cell without micro-rod arrays and Au nanoparticles. The conversion efficiency of the GaAs solar cell that was coated with Au nanoparticles on the patterned surface with micro-rod arrays can be improved from 14.1% to 19.9% under 1 sun AM 1.5G illumination. These results show that micro-rod arrays and Au nanoparticle coating can be applied together in surface patterning to achieve a novel cost-effective anti-reflection technology.

  2. Surface reflectance and conversion efficiency dependence of technologies for mitigating global warming

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, Ian [Solartran Pty Ltd., 12 Lentara St, Kenmore, Brisbane 4069 (Australia); Smith, Geoff [Physics and Advanced Materials, University of Technology, Sydney, PO Box 123, Broadway, New South Wales 2007 (Australia)

    2011-05-15

    A means of assessing the relative impact of different renewable energy technologies on global warming has been developed. All power plants emit thermal energy to the atmosphere. Fossil fuel power plants also emit CO{sub 2} which accumulates in the atmosphere and provides an indirect increase in global warming via the greenhouse effect. A fossil fuel power plant may operate for some time before the global warming due to its CO{sub 2} emission exceeds the warming due to its direct heat emission. When a renewable energy power plant is deployed instead of a fossil fuel power plant there may be a significant time delay before the direct global warming effect is less than the combined direct and indirect global warming effect from an equivalent output coal fired plant - the ''business as usual'' case. Simple expressions are derived to calculate global temperature change as a function of ground reflectance and conversion efficiency for various types of fossil fuelled and renewable energy power plants. These expressions are used to assess the global warming mitigation potential of some proposed Australian renewable energy projects. The application of the expressions is extended to evaluate the deployment in Australia of current and new geo-engineering and carbon sequestration solutions to mitigate global warming. Principal findings are that warming mitigation depends strongly on the solar to electric conversion efficiency of renewable technologies, geo-engineering projects may offer more economic mitigation than renewable energy projects and the mitigation potential of reforestation projects depends strongly on the location of the projects. (author)

  3. Size distribution of Parkfield’s microearthquakes reflects changes in surface creep rate

    Science.gov (United States)

    Tormann, Theresa; Wiemer, Stefan; Metzger, Sabrina; Michael, Andrew J.; Hardebeck, Jeanne L.

    2013-01-01

    The nucleation area of the series of M6 events in Parkfield has been shown to be characterized by low b-values throughout the seismic cycle. Since low b-values represent high differential stresses, the asperity structure seems to be always stably stressed and even unaffected by the latest main shock in 2004. However, because fault loading rates and applied shear stress vary with time, some degree of temporal variability of the b-value within stable blocks is to be expected. We discuss in this study adequate techniques and uncertainty treatment for a detailed analysis of the temporal evolution of b-values. We show that the derived signal for the Parkfield asperity correlates with changes in surface creep, suggesting a sensitive time resolution of the b-value stress meter, and confirming near-critical loading conditions within the Parkfield asperity.

  4. THE QUALITY OF THE SURFACE AT THE BEECH WOODTURNING

    Directory of Open Access Journals (Sweden)

    Mirela CHERCIU

    2015-05-01

    Full Text Available There have been experiments made with outside cylindrical beech woodturning with low cutting speed, and feed successively changed. We study, qualitative rather than quantitative, the roughnesss of the surface achieved. It interprets the appearance of each surface based on the theory of cutting considerations. Resulted surface images are given, photographed with a camera and microscope. It appears that here are no propellers generated by the cutting tool nose on the cylindrical part, excepting the situation of using high feeds.

  5. An analytical two-flow model to simulate the distribution of irradiance in coastal waters with a wind-roughed surface and bottom reflectance

    Science.gov (United States)

    Ma, Wei-Ming

    1997-06-01

    An analytical two-flow model is derived from the radiative transfer equation to simulate the distribution of irradiance in coastal waters with a wind-roughed surface and bottom reflectance. The model utilizes unique boundary conditions, including the surface slope of the downwelling and upwelling irradiance as well as the influence of wind and bottom reflectance on simulated surface reflectance. The developed model provides a simple mathematical concept for understanding the irradiant light flux and associated processes in coastal or fresh water as well as turbid estuarine waters. The model is applied to data from the Banana River and coastal Atlantic Ocean water off the east coast of central Florida, USA. The two-flow irradiance model is capable of simulating realistic above-surface reflectance signatures under wind-roughened air-water surface given realistic input parameters including a specular flux conversion coefficient, absorption coefficient, backscattering coefficient, atmospheric visibility, bottom reflectance, and water depth. The root-mean-squared error of the calculated above-surface reflectances is approximately 3% in the Banana River and is less than 15% in coastal Atlantic Ocean off the east of Florida. Result of the subsurface reflectance sensitivity analysis indicates that the specular conversion coefficient is the most sensitive parameter in the model, followed by the beam attenuation coefficient, absorption coefficient, water depth, backscattering coefficient, specular irradiance, diffuse irradiance, bottom reflectance, and wind speed. On the other hand, result of the above-surface reflectance sensitivity analysis indicates that the wind speed is the most important parameter, followed by bottom reflectance, attenuation coefficient, water depth, conversion coefficient, specular irradiance, downwelling irradiance, absorption coefficient, and backscattering coefficient. Model results depend on the accuracy of these parameters to a large degree and

  6. Quality factor due to roughness scattering of shear horizontal surface acoustic waves in nanoresonators

    NARCIS (Netherlands)

    Palasantzas, G.

    2008-01-01

    In this work we study the quality factor associated with dissipation due to scattering of shear horizontal surface acoustic waves by random self-affine roughness. It is shown that the quality factor is strongly influenced by both the surface roughness exponent H and the roughness amplitude w to

  7. Indices of quality surface water bodies in the planning of water resources

    Directory of Open Access Journals (Sweden)

    Rodríguez-Miranda, Juan Pablo

    2016-12-01

    Full Text Available This paper considers a review of the literature major and significant methods of quality indices of water applied in surface water bodies, used and proposed for assessing the significance of parameters of water quality in the assessment of surface water currents and they are usually used in making decisions for intervention and strategic prevention measures for those responsible for the conservation and preservation of watersheds where these water bodies belong. An exploratory methodology was applied to realize the conceptualization of each water quality index. As a result, it is observed that there are several important methods for determining the water quality index applied in surface water bodies.

  8. Apparent foraging success reflects habitat quality in an irruptive species, the Black-backed Woodpecker

    Science.gov (United States)

    Christopher T. Rota; Mark A. Rumble; Chad P. Lehman; Dylan C. Kesler; Joshua J. Millspaugh

    2015-01-01

    Dramatic fluctuations in food resources are a key feature of many habitats, and many species have evolved a movement strategy to exploit food resources that are unpredictable in space and time. The availability of food resources may be a particularly strong determinant of habitat quality for irruptive bird species. We studied the apparent foraging success of Black-...

  9. User Generated Diversity - Some reflections on how to improve the quality of amateur productions

    NARCIS (Netherlands)

    Helberger, N.; Leurdijk, A.G.D.; Munck, S.G.E. de

    2010-01-01

    The potential of user created content to make a meaningful contribution to media diversity is subject to debates. Central to these debates is the argument of the quality of amateur productions. This article will take a close look at this argument, and make some suggestions on how to improve the

  10. Are population differences in plant quality reflected in the preference and performance of two endoparasitoid wasps?

    NARCIS (Netherlands)

    Gols, R.; Dam, van N.M.; Raaijmakers, C.E.; Dicke, M.; Harvey, J.A.

    2009-01-01

    In recent years, increasing attention has been paid in exploring the role of direct plant defence, through the production of allelochemicals, on the performance of parasitoid wasps and their hosts. However, few studies have determined if parasitoids can detect differences in plant quality and thus

  11. User generated diversity: some reflections on how to improve the quality of amateur productions

    NARCIS (Netherlands)

    Helberger, N.; Leurdijk, A.; de Munck, S.

    2010-01-01

    The potential of user created content to make a meaningful contribution to media diversity is subject to debates. Central to these debates is the argument of the quality of amateur productions. This article will take a close look at this argument, and make some suggestions on how to improve the

  12. The Minimum Data Set Depression Quality Indicator: Does It Reflect Differences in Care Processes?

    Science.gov (United States)

    Simmons, S.F.; Cadogan, M.P.; Cabrera, G.R.; Al-Samarrai, N.R.; Jorge, J.S.; Levy-Storms, L.; Osterweil, D.; Schnelle, J.F.

    2004-01-01

    Purpose. The objective of this work was to determine if nursing homes that score differently on prevalence of depression, according to the Minimum Data Set (MDS) quality indicator, also provide different processes of care related to depression. Design and Methods. A cross-sectional study with 396 long-term residents in 14 skilled nursing…

  13. Research on the effect of coverage rate on the surface quality in laser direct writing process

    Science.gov (United States)

    Pan, Xuetao; Tu, Dawei

    2017-07-01

    Direct writing technique is usually used in femtosecond laser two-photon micromachining. The size of the scanning step is an important factor affecting the surface quality and machining efficiency of micro devices. According to the mechanism of two-photon polymerization, combining the distribution function of light intensity and the free radical concentration theory, we establish the mathematical model of coverage of solidification unit, then analyze the effect of coverage on the machining quality and efficiency. Using the principle of exposure equivalence, we also obtained the analytic expressions of the relationship among the surface quality characteristic parameters of microdevices and the scanning step, and carried out the numerical simulation and experiment. The results show that the scanning step has little influence on the surface quality of the line when it is much smaller than the size of the solidification unit. However, with increasing scanning step, the smoothness of line surface is reduced rapidly, and the surface quality becomes much worse.

  14. Variability in surface infrared reflectance of thirteen nitrile rubber gloves at key wavelengths for analysis of captan.

    Science.gov (United States)

    Phalen, R N; Que Hee, Shane S

    2007-02-01

    The aim of this study was to investigate the surface variability of 13 powder-free, unlined, and unsupported nitrile rubber gloves using attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectrophotometry at key wavelengths for analysis of captan contamination. The within-glove, within-lot, and between-lot variability was measured at 740, 1124, 1252, and 1735 cm(-1), the characteristic captan reflectance minima wavelengths. Three glove brands were assessed after conditioning overnight at relative humidity (RH) values ranging from 2 +/- 1 to 87 +/- 4% and temperatures ranging from -8.6 +/- 0.7 to 59.2 +/- 0.9 degrees C. For all gloves, 1735 cm(-1) provided the lowest background absorbance and greatest potential sensitivity for captan analysis on the outer glove surface: absorbances ranged from 0.0074 +/- 0.0005 (Microflex) to 0.0195 +/- 0.0024 (SafeSkin); average within-glove coefficients of variation (CV) ranged from 2.7% (Best, range 0.9-5.3%) to 10% (SafeSkin, 1.2-17%); within-glove CVs greater than 10% were for one brand (SafeSkin); within-lot CVs ranged from 2.8% (Best N-Dex) to 28% (SafeSkin Blue); and between-lot variation was statistically significant (p < or = 0.05) for all but two SafeSkin lots. The RH had variable effects dependent on wavelength, being minimal at 1735, 1252, and 1124 cm(-1) and highest at 3430 cm(-1) (O-H stretch region). There was no significant effect of temperature conditioning. Substantial within-glove, within-lot, and between-lot variability was observed. Thus, surface analysis using ATR-FT-IR must treat glove brands and lots as different. ATR-FT-IR proved to be a useful real-time analytical tool for measuring glove variability, detecting surface humidity effects, and choosing selective and sensitive wavelengths for analysis of nonvolatile surface contaminants.

  15. Surface topography analysis for dimensional quality control of replication at the micrometre scale

    DEFF Research Database (Denmark)

    Balcon, M.; Marinello, F.; Tosello, Guido

    2011-01-01

    Replication of geometrical features and surfaces are present at different production levels, from realization of moulds to final product. Geometrical features must be reproduced within specification limits, to ensure product functionality . In order to control the replication quality, mould...... and replica surfaces must be quantitatively analysed and compared. In the present work, reference simulated surfaces were considered and studied in order to evaluate the effectiveness and traceability of different analysis tools for replication quality control. Topographies were analysed simulating different...

  16. QUALITY OF INITIAL TEACHER EDUCATION: REFLECTIONS ON WHAT IS BEING RESEARCHED

    Directory of Open Access Journals (Sweden)

    Josimar de Aparecido Vieira

    2009-12-01

    Full Text Available This work is discussed, in general, the state of knowledge on research dealing with the quality of the initial training of teachers. Presents an analytical and critical reading of the situation of the quality of the initial training of teachers from the analysis of the theoretical bases produced in the last decade. For this, initially, are presented some considerations on the development of this process, followed by an analysis on the issue of training. Following are considered some of the dilemmas or problems that have been addressed in the study area, suggesting mechanisms or alternative solutions. The main source of data used is the Bank of the CAPES Theses which is available on the home page http://servicos.capes.gov.br/capesdw/, for the period from 2004 until 2006. Was used to search by typing the words "initial teacher training" in the "subject", which in 2004 were examined 33 abstracts were selected and these 15, in 2005 were examined 42 abstracts, of which 07 were deployed in 2006 and were seen 44 abstracts of which 21 have been considered because they relate to the quality of initial teacher education. Involved in this analysis, this study points out some principles and data that can help with the process of initial teacher training, pointing to possible review some indicators of pedagogical projects of degree courses. Emphasizes that the specificity and multidimensionality of the performance of the teacher raises the formulation of a set of information relevant to the qualification of objectives and practices of the initial key step in the process of learning to teach. Key words: Quality of education, initial training, university education, state of knowledge; indicators.

  17. Peer Review and Reflective Teaching Practices: An Effective Mechanism for Quality Enhancement in Higher Education

    OpenAIRE

    Raj, Sony Jalarajan; Massey, Susan R.; Jose, Soumya

    2017-01-01

    Quality education and teacher accountability are predominant issues generating apprehension in higher education. Traditional methods of evaluation are giving way to more contemporary methods. One technique that is being implemented in many universities throughout the world that provides feedback and improves pedagogical approaches is a formative and collaborative process known as peer review of teaching (PRT). Review of the literature included 34 studies which identified five themes that offe...

  18. Self-reflection as a Tool to Increase Hospitalist Participation in Readmission Quality Improvement.

    Science.gov (United States)

    Rana, Vipulkumar; Thapa, Bipin; Saini, Sumanta Chaudhuri; Nagpal, Pooja; Segon, Ankur; Fletcher, Kathlyn; Lamb, Geoffrey

    Reducing 30-day readmissions is a national priority. Although multipronged programs have been shown to reduce readmissions, the role of the individual hospitalist physician in reducing readmissions is not clear. We evaluated the effect of physicians' self-review of their own readmission cases on the 30-day readmission rate. Over a 1-year period, hospitalists were sent their individual readmission rates and cases on a weekly basis. They reviewed their cases and completed a data abstraction tool. In addition, a facilitator led small group discussion about common causes of readmission and ways to prevent such readmissions. Our preintervention readmission rate was 16.16% and postintervention was 14.99% (P = .76). Among hospitalists on duty, nearly all participated in scheduled facilitated discussions. Self-review was completed in 67% of the cases. A facilitated reflective practice intervention increased hospitalist participation and awareness in the mission to reduce readmissions and this intervention resulted in a nonsignificant trend in readmission reduction.

  19. Adiabatic surface thermometer for improved production braze quality

    International Nuclear Information System (INIS)

    Dittbenner, G.R.

    1975-01-01

    An adiabatic surface thermometer was developed to control automatically the critical temperature-time cycle of a production vacuum-brazing process. Investigations revealed that optimum braze-joint strength required precise control of the brazing temperature. Spot-welded thermocouples could not be used because the spot welds cause surface damage. This thermometer touches the surface and uses a differential thermocouple and heater to measure surface temperature without heat flow, thereby eliminating large errors caused by conduction losses common to conventional spring-loaded thermocouples. Temperatures in air or vacuum are measured to 800 0 C with errors less than 5 0 C. This thermometer has minimized the rejection of production parts, resulting in a cost saving to the U. S. Energy Research and Development Administration

  20. Non-Destructive Quality Evaluation of Pepper (Capsicum annuum L. Seeds Using LED-Induced Hyperspectral Reflectance Imaging

    Directory of Open Access Journals (Sweden)

    Changyeun Mo

    2014-04-01

    Full Text Available In this study, we developed a viability evaluation method for pepper (Capsicum annuum L. seeds based on hyperspectral reflectance imaging. The reflectance spectra of pepper seeds in the 400–700 nm range are collected from hyperspectral reflectance images obtained using blue, green, and red LED illumination. A partial least squares–discriminant analysis (PLS-DA model is developed to classify viable and non-viable seeds. Four spectral ranges generated with four types of LEDs (blue, green, red, and RGB, which were pretreated using various methods, are investigated to develop the classification models. The optimal PLS-DA model based on the standard normal variate for RGB LED illumination (400–700 nm yields discrimination accuracies of 96.7% and 99.4% for viable seeds and nonviable seeds, respectively. The use of images based on the PLS-DA model with the first-order derivative of a 31.5-nm gap for red LED illumination (600–700 nm yields 100% discrimination accuracy for both viable and nonviable seeds. The results indicate that a hyperspectral imaging technique based on LED light can be potentially applied to high-quality pepper seed sorting.

  1. Impact of dielectric parameters on the reflectivity of 3C–SiC wafers with a rough surface morphology in the reststrahlen region

    International Nuclear Information System (INIS)

    Engelbrecht, J.A.A.; Janzén, E.; Henry, A.; Rooyen, I.J. van

    2014-01-01

    A layer-on-substrate model is used to obtain the infrared reflectance for 3C–SiC with a rough surface morphology. The effect of varying dielectric parameters of the “damaged layer” on the observed reflectivity of the 3C–SiC in the reststrahlen region is assessed. Different simulated reflectance spectra are obtained to those if the dielectric parameters of the “substrate” were varied. Most notable changes in the shape of the simulated reststrahlen peak are observed for changes in the high frequency dielectric constant, the phonon damping constant, the phonon frequencies and “thickness” of damaged surface layer.

  2. Impact of dielectric parameters on the reflectivity of 3C–SiC wafers with a rough surface morphology in the reststrahlen region

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, J.A.A., E-mail: Japie.Engelbrecht@nmmu.ac.za [Physics Department, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Janzén, E.; Henry, A. [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Rooyen, I.J. van [Fuel Performance and Design Department, Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-6188 (United States)

    2014-04-15

    A layer-on-substrate model is used to obtain the infrared reflectance for 3C–SiC with a rough surface morphology. The effect of varying dielectric parameters of the “damaged layer” on the observed reflectivity of the 3C–SiC in the reststrahlen region is assessed. Different simulated reflectance spectra are obtained to those if the dielectric parameters of the “substrate” were varied. Most notable changes in the shape of the simulated reststrahlen peak are observed for changes in the high frequency dielectric constant, the phonon damping constant, the phonon frequencies and “thickness” of damaged surface layer.

  3. An investigation of the reflection of low energy electrons from the surfaces of layered transition metal dichalcogenides

    International Nuclear Information System (INIS)

    Smith, A.E.; Mohamed, M.H.; Wohlenberg, T.; Johnson, E.; Chadderton, L.T.; Moeller, P.J.

    1980-01-01

    Experimental measurements, using the total current spectroscopy (TCS) technique, on the energy dependence of the reflection of low energy electrons from clean surfaces of layered transition metal dichalcogenides are reported for the molybdenum semiconductor compounds 2H-MoS 2 and 2H-MoSe 2 . A simple model calculation involving both elastic and inelastic scattering is presented and correspondence established with the experimental spectra. In this picture information on the electronic band structure of the materials can then be extracted from the single particle component of the inelastic scattering. The model is extended to show that a feature in the 2H-MoS 2 experimental spectrum may be attributed to the excitation of an intermediate plasmon. (Auth.)

  4. Shear-wave seismic reflection imaging and impedance inversion for a near-surface point-bar

    Science.gov (United States)

    Benton, N. W.; Morrison, M.; Lorenzo, J. M.; Odom, B.; Clift, P. D.; Olson, E.; Gostic, A.

    2017-12-01

    Imaging and inversion of SH-waves are useful to detect, map, and quantitatively characterize near-surface point-bar strata. We conduct a horizontally-polarized (SH) reflection survey across and along a near-surface (9 - 40 m) downstream point-bar. We invert for shear-impedance profiles and correlate our interpretation to electrical conductivity (EC) logs in adjacent wells to study the internal architecture and lithology of point-bars. We acquire two common-midpoint (CMP) SH-wave seismic reflection lines at False River (Point Coupee Parish, Louisiana). A 104 m long seismic line (L1) is oriented orthogonal (NW - SE) to point-bar strike. A second line (L2) is 48 m long and set parallel to point-bar strike (NE - SW). Two EC wells lie 33 m apart. Both wells are parallel with respect to the L1 survey and offset from it by 15 m. EC log measurements range from 1 - 25 m depth. Interference of Love-waves prevents seismic imaging at depths less than 9 m. The L1 and L2 data sets are inverted for shear-impedance using a model-based band-limited impedance (BLIMP) algorithm that incorporates a low-frequency velocity model. This model is also used for the depthing processing. The L1 cross-section shows coherent dipping reflection events ( 4 - 7º) from 0.15 - 0.35 s (10 - 40 m). The corresponding shear-impedance profile also reveals coherent and dipping impedance contrasts that grow in magnitude with increasing depth. The L2 cross-section shows comparatively less dip ( 1º) as well as sharper and shallower continuity of reflection events (0.1 - 0.28 s TWT or 9 - 25 m). Depth-converted (TVD) seismic amplitudes and impedance values correlate to near-surface point-bar geology via superposition of log data. The first well (W5) shows distinct EC local maxima (+50 - 70 mS/m) at 14.5 and 15.5 m depth that correlate well with the seismic amplitudes and impedance values from both L1 and L2 data sets. The second well (W7) shows comparatively lower local maxima (+40 - 60 mS/m) but at greater

  5. Reflection-time-of-flight spectrometer for two-electron (e,2e) coincidence spectroscopy on surfaces

    International Nuclear Information System (INIS)

    Kirschner, J.; Kerherve, G.; Winkler, C.

    2008-01-01

    In this article, a novel time-of-flight spectrometer for two-electron-emission (e,2e/γ,2e) correlation spectroscopy from surfaces at low electron energies is presented. The spectrometer consists of electron optics that collect emitted electrons over a solid angle of approximately 1 sr and focus them onto a multichannel plate using a reflection technique. The flight time of an electron with kinetic energy of E kin ≅25 eV is around 100 ns. The corresponding time- and energy resolution are typically ≅1 ns and ≅0.65 eV, respectively. The first (e,2e) data obtained with the present setup from a LiF film are presented

  6. Scaled multisensor inspection of extended surfaces for industrial quality control

    Science.gov (United States)

    Kayser, Daniel; Bothe, Thorsten; Osten, Wolfgang

    2002-06-01

    Reliable real-time surface inspection of extended surfaces with high resolution is needed in several industrial applications. With respect to an efficient application to extended technical components such as aircraft or automotive parts, the inspection system has to perform a robust measurement with a ratio of less then 10-6 between depth resolution and lateral extension. This ratio is at least one order beyond the solutions that are offered by existing technologies. The concept of scaled topometry consists of arranging different optical measurement techniques with overlapping ranges of resolution systematically in order to receive characteristic surface information with the required accuracy. In such a surface inspection system, an active algorithm combines measurements on several scales of resolution and distinguishes between local fault indicating structures with different extensions and global geometric properties. The first part of this active algorithm finds indications of critical surface areas in the data of every measurement and separates them into different categories. The second part analyses the detected structures in the data with respect to their resolution and decides whether a further local measurement with a higher resolution has to be performed. The third part positions the sensors and starts the refined measurements. The fourth part finally integrates the measured local data set into the overall data mesh. We have constructed a laboratory setup capable of measuring surfaces with extensions up to 1500mm x 1000mm x 500mm (in x-, y- and z-direction respectively). Using this measurement system we will be able to separate the fault indicating structures on the surface from the global shape and to classify the detected structures according to their extensions and characteristic shapes simultaneously. The level of fault detection probability will be applicable by input parameter control.

  7. Comparison of Anti-Reflective Coated and Uncoated Surfaces Figured by Pitch-Polishing and Magneto-Rheological Processes

    International Nuclear Information System (INIS)

    Chow, R.; Thomas, M.D.; Bickel, R.; Taylor, J.R.

    2002-01-01

    When completed, the National Ignition Facility (NIF) will provide laser energies in the Mega-joule range. Successful pulse amplification to these extremely high levels requires that all small optics, found earlier in the beamline, have stringent surface and laser fluence requirements. In addition, they must operate reliably for 30 years constituting hundreds of thousands of shots. As part of the first four beamlines, spherical and aspherical lenses were required for the beam relaying telescopes. The magneto-rheological technique allows for faster and more accurate finishing of aspheres. The spherical and aspherical lenses were final figured using both conventional-pitch polishing processes for high quality laser optics and the magneto-rheological finishing process. The purpose of this paper is to compare the surface properties between these two finishing processes. Some lenses were set aside from production for evaluation. The surface roughness in the mid-frequency range was measured and the scatter was studied. Laser damage testing at 1064 nm (3-ns pulse width) was performed on surfaces in both the uncoated and coated condition.

  8. Modification of kaolinite surfaces through mechanochemical activation with quartz: A diffuse reflectance infrared fourier transform and chemometrics study.

    Science.gov (United States)

    Carmody, Onuma; Frost, Ray L; Kristóf, János; Kokot, Serge; Kloprogge, J Theo; Makó, Eva

    2006-12-01

    Studies of kaolinite surfaces are of industrial importance. One useful method for studying the changes in kaolinite surface properties is to apply chemometric analyses to the kaolinite surface infrared spectra. A comparison is made between the mechanochemical activation of Kiralyhegy kaolinites with significant amounts of natural quartz and the mechanochemical activation of Zettlitz kaolinite with added quartz. Diffuse reflectance infrared Fourier transform (DRIFT) spectra were analyzed using principal component analysis (PCA) and multi-criteria decision making (MCDM) methods, the preference ranking organization method for enrichment evaluations (PROMETHEE) and geometrical analysis for interactive assistance (GAIA). The clear discrimination of the Kiralyhegy spectral objects on the two PC scores plots (400-800 and 800-2030 cm(-1)) indicated the dominance of quartz. Importantly, no ordering of any spectral objects appeared to be related to grinding time in the PC plots of these spectral regions. Thus, neither the kaolinite nor the quartz are systematically responsive to grinding time according to the spectral criteria investigated. The third spectral region (2600-3800 cm(-1), OH vibrations), showed apparent systematic ordering of the Kiralyhegy and, to a lesser extent, Zettlitz spectral objects with grinding time. This was attributed to the effect of the natural quartz on the delamination of kaolinite and the accompanying phenomena (i.e., formation of kaolinite spheres and water). The mechanochemical activation of kaolinite and quartz, through dry grinding, results in changes to the surface structure. Different grinding times were adopted to study the rate of destruction of the kaolinite and quartz structures. This relationship (i.e., grinding time) was classified using PROMETHEE and GAIA methodology.

  9. An Algorithm for the Retrieval of 30-m Snow-Free Albedo from Landsat Surface Reflectance and MODIS BRDF

    Science.gov (United States)

    Shuai, Yanmin; Masek, Jeffrey G.; Gao, Feng; Schaaf, Crystal B.

    2011-01-01

    We present a new methodology to generate 30-m resolution land surface albedo using Landsat surface reflectance and anisotropy information from concurrent MODIS 500-m observations. Albedo information at fine spatial resolution is particularly useful for quantifying climate impacts associated with land use change and ecosystem disturbance. The derived white-sky and black-sky spectral albedos maybe used to estimate actual spectral albedos by taking into account the proportion of direct and diffuse solar radiation arriving at the ground. A further spectral-to-broadband conversion based on extensive radiative transfer simulations is applied to produce the broadband albedos at visible, near infrared, and shortwave regimes. The accuracy of this approach has been evaluated using 270 Landsat scenes covering six field stations supported by the SURFace RADiation Budget Network (SURFRAD) and Atmospheric Radiation Measurement Southern Great Plains (ARM/SGP) network. Comparison with field measurements shows that Landsat 30-m snow-free shortwave albedos from all seasons generally achieve an absolute accuracy of +/-0.02 - 0.05 for these validation sites during available clear days in 2003-2005,with a root mean square error less than 0.03 and a bias less than 0.02. This level of accuracy has been regarded as sufficient for driving global and regional climate models. The Landsat-based retrievals have also been compared to the operational 16-day MODIS albedo produced every 8-days from MODIS on Terra and Aqua (MCD43A). The Landsat albedo provides more detailed landscape texture, and achieves better agreement (correlation and dynamic range) with in-situ data at the validation stations, particularly when the stations include a heterogeneous mix of surface covers.

  10. water quality assessment of underground and surface water ...

    African Journals Online (AJOL)

    Dr Osondu

    Water quality assessment in the Ethiopian highlands is crucial owing to increasing ... and provide information for formulating appropriate framework for an integrated ... with four seasons (rainy, dry period, small rains ..... treatment. Annual conference proceedings, American Water Works ... Towns' water supply and sanitation.

  11. evaluation of surface water quality charac- teristics in ogun ...

    African Journals Online (AJOL)

    DEPT OF AGRICULTURAL ENGINEERING

    total viable counts as the major water quality indicators. The PC2 had Temperature, COD,. Phosphate, heavy metals (Zn and Hg) and Fecal coliform as responsible for the observed 19% of the variation within the location. Organic constituent (BOD5), which has direct influence on dissolved oxygen depletion in the water.

  12. Influence of discharged effluent on the quality of surface water ...

    African Journals Online (AJOL)

    ... higher values of determinants obtained from sampling points close to the wastewater treatment plant and the mine exit channels strongly revealed their influence on the general quality of the stream. Detection of metals such as cadmium and lead above acceptable limits has dire consequences across the food chain.

  13. Mitochondrial Biomarkers Reflect Semen Quality: Results from the MARCHS Study in Chongqing, China.

    Science.gov (United States)

    Zhang, Guowei; Wang, Zhi; Ling, Xi; Zou, Peng; Yang, Huan; Chen, Qing; Zhou, Niya; Sun, Lei; Gao, Jianfang; Zhou, Ziyuan; Cao, Jia; Ao, Lin

    2016-01-01

    Unexplained infertility requires that more sensitive and mechanism-based biomarkers should be developed and used independently of or in addition to conventional semen parameters for an infertility diagnosis. In the present study, semen samples were collected from young men participating in the Male Reproductive Health in Chongqing College students (MARCHS) cohort study in the follow-up stage in 2014. Conventional semen parameters were measured in all 656 participants, whereas sperm mitochondrial membrane potential (MMP), mitochondrial DNA copy number (mtDNAcn), mtDNA integrity and apoptotic parameters were measured among 627, 386, 362, and 628 participants, respectively. We found that sperm MMP was significantly positively correlated with all of conventional semen parameters including semen volume (r = 0.090, p = 0.025), sperm concentration (r = 0.301, psemen quality in a general population, and the study provides a baseline for the effects of population characteristics and lifestyles on such mitochondrial markers.

  14. Some reflections on researches of Future Earth changes in air quality and climate

    Directory of Open Access Journals (Sweden)

    Xiao-Ye Zhang

    2015-06-01

    Full Text Available Within the context of our current research and understanding of climate change, decisionmakers are particularly concerned with the extent of future climate change, its comprehensive impact, and the types of socioeconomic pathways available with respect to mitigation and adaptation. Among the factors contributing to these important issues, the role of air pollution in global and regional climate warming remains as one of the largest uncertainties. On the basis of understanding of the IPCC Fifth Assessment Report, specifically, in the role of air pollution in climate change, scenarios establishment, and relationship between the Shared Socioeconomic Pathways (SSPs and Representative Concentration Pathways (RCPs. Weaknesses and reflections were discussed here especially in strengthening impact, adaptation and mitigation research that related with changes in air pollution and climate. In the future, there are needs to in-depth understand how and why the air pollution in China is so serious and changing; to understand the likely future changes in air pollution and climate; to strengthen comprehensive impact research and selective reduction strategies related to changes in air pollution and climate. Furthermore, this study outlines the needs to develop strategies to close the loop of differential impacts and costs; to establish co-benefits and sustainable development goals, to identify the crucial risks and options for synergies/trade-offs; to integrate sector-specific details with macro-economics, and to integrate the assessments of the various policy instruments. All these focus areas will help to facilitate the transition of economic development patterns towards green and low-carbon development.

  15. Evidence for Surface Water Ice in the Lunar Polar Regions Using Reflectance Measurements from the Lunar Orbiter Laser Altimeter and Temperature Measurements from the Diviner Lunar Radiometer Experiment

    Science.gov (United States)

    Fisher, Elizabeth A.; Lucey, Paul G.; Lemelin, Myriam; Greenhagen, Benjamin T.; Siegler, Matthew A.; Mazarico, Erwan; Aharonson, Oded; Williams, Jean-Pierre; Hayne, Paul O.; Neumann, Gregory A.; hide

    2017-01-01

    We find that the reflectance of the lunar surface within 5 deg of latitude of theSouth Pole increases rapidly with decreasing temperature, near approximately 110K, behavior consistent with the presence of surface water ice. The North polar region does not show this behavior, nor do South polar surfaces at latitudes more than 5 deg from the pole. This South pole reflectance anomaly persists when analysis is limited to surfaces with slopes less than 10 deg to eliminate false detection due to the brightening effect of mass wasting, and also when the very bright south polar crater Shackleton is excluded from the analysis. We also find that south polar regions of permanent shadow that have been reported to be generally brighter at 1064 nm do not show anomalous reflectance when their annual maximum surface temperatures are too high to preserve water ice. This distinction is not observed at the North Pole. The reflectance excursion on surfaces with maximum temperatures below 110K is superimposed on a general trend of increasing reflectance with decreasing maximum temperature that is present throughout the polar regions in the north and south; we attribute this trend to a temperature or illumination-dependent space weathering effect (e.g. Hemingway et al. 2015). We also find a sudden increase in reflectance with decreasing temperature superimposed on the general trend at 200K and possibly at 300K. This may indicate the presence of other volatiles such as sulfur or organics. We identified and mapped surfaces with reflectances so high as to be unlikely to be part of an ice-free population. In this south we find a similar distribution found by Hayne et al. 2015 based on UV properties. In the north a cluster of pixels near that pole may represent a limited frost exposure.

  16. Evidence for surface water ice in the lunar polar regions using reflectance measurements from the Lunar Orbiter Laser Altimeter and temperature measurements from the Diviner Lunar Radiometer Experiment

    Science.gov (United States)

    Fisher, Elizabeth A.; Lucey, Paul G.; Lemelin, Myriam; Greenhagen, Benjamin T.; Siegler, Matthew A.; Mazarico, Erwan; Aharonson, Oded; Williams, Jean-Pierre; Hayne, Paul O.; Neumann, Gregory A.; Paige, David A.; Smith, David E.; Zuber, Maria T.

    2017-08-01

    We find that the reflectance of the lunar surface within 5° of latitude of the South Pole increases rapidly with decreasing temperature, near ∼110 K, behavior consistent with the presence of surface water ice. The North polar region does not show this behavior, nor do South polar surfaces at latitudes more than 5° from the pole. This South pole reflectance anomaly persists when analysis is limited to surfaces with slopes less than 10° to eliminate false detection due to the brightening effect of mass wasting, and also when the very bright south polar crater Shackleton is excluded from the analysis. We also find that south polar regions of permanent shadow that have been reported to be generally brighter at 1064 nm do not show anomalous reflectance when their annual maximum surface temperatures are too high to preserve water ice. This distinction is not observed at the North Pole. The reflectance excursion on surfaces with maximum temperatures below 110 K is superimposed on a general trend of increasing reflectance with decreasing maximum temperature that is present throughout the polar regions in the north and south; we attribute this trend to a temperature or illumination-dependent space weathering effect (e.g. Hemingway et al., 2015). We also find a sudden increase in reflectance with decreasing temperature superimposed on the general trend at 200 K and possibly at 300 K. This may indicate the presence of other volatiles such as sulfur or organics. We identified and mapped surfaces with reflectances so high as to be unlikely to be part of an ice-free population. In this south we find a similar distribution found by Hayne et al. (2015) based on UV properties. In the north a cluster of pixels near that pole may represent a limited frost exposure.

  17. Effective signaling of surface boundaries by L-vertices reflect the consistency of their contrast in natural images.

    Science.gov (United States)

    Vessel, Edward A; Biederman, Irving; Subramaniam, Suresh; Greene, Michelle R

    2016-07-01

    An L-vertex, the point at which two contours coterminate, provides highly reliable evidence that a surface terminates at that vertex, thus providing the strongest constraint on the extraction of shape from images (Guzman, 1968). Such vertices are pervasive in our visual world but the importance of a statistical regularity about them has been underappreciated: The contours defining the vertex are (almost) always of the same direction of contrast with respect to the background (i.e., both darker or both lighter). Here we show that when the two contours are of different directions of contrast, the capacity of the L-vertex to signal the termination of a surface, as reflected in object recognition, is markedly reduced. Although image statistics have been implicated in determining the connectivity in the earliest cortical visual stage (V1) and in grouping during visual search, this finding provides evidence that such statistics are involved in later stages where object representations are derived from two-dimensional images.

  18. Surface quality inspection of PbWO4 crystals by grazing incidence X-ray diffraction

    International Nuclear Information System (INIS)

    Mengucci, P.; Di Cristoforo, A.; Lebeau, M.; Majni, G.; Paone, N.; Pietroni, P.; Rinaldi, D.

    2005-01-01

    High-quality scintillating crystals are required for applications in radiographic systems and high-energy physics detectors to achieve the specified optical properties. In order to study the state of the single crystals surface we propose the use of the grazing incidence X-ray diffraction (GID) technique. This technique allows performing a depth profiling of the sample by changing the incidence angle of the X-ray beam with respect to the sample surface. In this work, two samples of a large PbWO 4 (PWO) single crystal exhibiting different surface roughness values have been studied. Results have shown that GID is a suitable technique for surface quality inspection

  19. Assessment of surface water quality using hierarchical cluster analysis

    Directory of Open Access Journals (Sweden)

    Dheeraj Kumar Dabgerwal

    2016-02-01

    Full Text Available This study was carried out to assess the physicochemical quality river Varuna inVaranasi,India. Water samples were collected from 10 sites during January-June 2015. Pearson correlation analysis was used to assess the direction and strength of relationship between physicochemical parameters. Hierarchical Cluster analysis was also performed to determine the sources of pollution in the river Varuna. The result showed quite high value of DO, Nitrate, BOD, COD and Total Alkalinity, above the BIS permissible limit. The results of correlation analysis identified key water parameters as pH, electrical conductivity, total alkalinity and nitrate, which influence the concentration of other water parameters. Cluster analysis identified three major clusters of sampling sites out of total 10 sites, according to the similarity in water quality. This study illustrated the usefulness of correlation and cluster analysis for getting better information about the river water quality.International Journal of Environment Vol. 5 (1 2016,  pp: 32-44

  20. Quantifying the Uncertainty in High Spatial and Temporal Resolution Synthetic Land Surface Reflectance at Pixel Level Using Ground-Based Measurements

    Science.gov (United States)

    Kong, J.; Ryu, Y.

    2017-12-01

    Algorithms for fusing high temporal frequency and high spatial resolution satellite images are widely used to develop dense time-series land surface observations. While many studies have revealed that the synthesized frequent high spatial resolution images could be successfully applied in vegetation mapping and monitoring, validation and correction of fused images have not been focused than its importance. To evaluate the precision of fused image in pixel level, in-situ reflectance measurements which could account for the pixel-level heterogeneity are necessary. In this study, the synthetic images of land surface reflectance were predicted by the coarse high-frequency images acquired from MODIS and high spatial resolution images from Landsat-8 OLI using the Flexible Spatiotemporal Data Fusion (FSDAF). Ground-based reflectance was measured by JAZ Spectrometer (Ocean Optics, Dunedin, FL, USA) on rice paddy during five main growth stages in Cheorwon-gun, Republic of Korea, where the landscape heterogeneity changes through the growing season. After analyzing the spatial heterogeneity and seasonal variation of land surface reflectance based on the ground measurements, the uncertainties of the fused images were quantified at pixel level. Finally, this relationship was applied to correct the fused reflectance images and build the seasonal time series of rice paddy surface reflectance. This dataset could be significant for rice planting area extraction, phenological stages detection, and variables estimation.

  1. Effects of Surface BRDF on the OMI Cloud and NO2 Retrievals: A New Approach Based on Geometry-Dependent Lambertian Equivalent Reflectivity (GLER) Derived from MODIS

    Science.gov (United States)

    Vasilkov, Alexander; Qin, Wenhan; Krotkov, Nickolay; Lamsal, Lok; Spurr, Robert; Haffner, David; Joiner, Joanna; Yang, Eun-Su; Marchenko, Sergey

    2017-01-01

    The Ozone Monitoring Instrument (OMI) cloud and NO2 algorithms use a monthly gridded surface reflectivity climatology that does not depend upon the observation geometry. In reality, reflection of incoming direct and diffuse solar light from land or ocean surfaces is sensitive to the sun sensor geometry. This dependence is described by the bidirectional reflectance distribution function (BRDF). To account for the BRDF, we propose to use a new concept of geometry-dependent Lambertian equivalent reflectivity (GLER). Implementation within the existing OMI cloud and NO2 retrieval infrastructure requires changes only to the input surface reflectivity database. GLER is calculated using a vector radiative transfer model with high spatial resolution BRDF information from MODIS over land and the Cox Munk slope distribution over ocean with a contribution from water-leaving radiance. We compare GLER and climatological LER at 466 nm, which is used in the OMI O2-O2cloud algorithm to derive effective cloud fractions. A detailed comparison of the cloud fractions and pressures derived with climatological and GLERs is carried out. GLER and corresponding retrieved cloud products are then used as input to the OMI NO2 algorithm. We find that replacing the climatological OMI-based LERs with GLERs can increase NO2 vertical columns by up to 50 % in highly polluted areas; the differences include both BRDF effects and biases between the MODIS and OMI-based surface reflectance data sets. Only minor changes to NO2 columns (within 5 %) are found over unpolluted and overcast areas.

  2. AISI/DOE Technology Roadmap Program: Improved Surface Quality of Exposed Automotive Sheet Steels

    Energy Technology Data Exchange (ETDEWEB)

    John G. Speer; David K. Matlock; Noel Meyers; Young-Min Choi

    2002-10-10

    Surface quality of sheet steels is an important economic and technical issue for applications such as critical automotive surfaces. This project was therefore initiated to develop a more quantitative methodology for measuring surface imperfections, and to assess their response to forming and painting, particularly with respect to their visibility or invisibility after painting. The objectives were met, and included evaluation of a variety of imperfections present on commercial sheet surfaces or simulated using methods developed in the laboratory. The results are expected to have significant implications with respect to the methodology for assessing surface imperfections, development of quantitative criteria for surface inspection, and understanding and improving key painting process characteristics that influence the perceived quality of sheet steel surfaces.

  3. Surface Quality of Staggered PCD End Mill in Milling of Carbon Fiber Reinforced Plastics

    Directory of Open Access Journals (Sweden)

    Guangjun Liu

    2017-02-01

    Full Text Available Machined surface quality determines the reliability, wear resistance and service life of carbon fiber reinforced plastic (CFRP workpieces. In this work, the formation mechanism of the surface topography and the machining defects of CFRPs are proposed, and the influence of milling parameters and fiber cutting angles on the surface quality of CFRPs is obtained, which can provide a reference for extended tool life and good surface quality. Trimming and slot milling tests of unidirectional CFRP laminates are performed. The surface roughness of the machined surface is measured, and the influence of milling parameters on the surface roughness is analyzed. A regression model for the surface roughness of CFRP milling is established. A significance test of the regression model is conducted. The machined surface topography of milling CFRP unidirectional laminates with different fiber orientations is analyzed, and the effect of fiber cutting angle on the surface topography of the machined surface is presented by using a digital super depth-of-field microscope and scanning electron microscope (SEM. To study the influence of fiber cutting angle on machining defects, the machined topography under different fiber orientations is analyzed. The slot milling defects and their formation mechanism under different fiber cutting angles are investigated.

  4. Sea Surface Height Deviation, Aviso, 0.25 degrees, Global, Science Quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Aviso Sea Surface Height Deviation is the deviation from the mean geoid as measured from 1993 - 1995. This is Science Quality data.

  5. The impact of industries on surface water quality of River Ona and ...

    African Journals Online (AJOL)

    Samples of water from two rivers (River Ona and River Alaro) in Oluyole ... were higher in the industrial zones than those found in the upstream of both rivers. ... Key words: River Ona, River Alaro, industrial discharges, surface water quality.

  6. Fish samples as bioindicator of environmental quality: synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF)

    International Nuclear Information System (INIS)

    Vives, Ana Elisa Sirito de; Moreira, Silvana; Brienza, Sandra Maria Boscolo; Zucchi, Orgheda Luiza Araujo Domingues; Nascimento Filho, Virgilio Franco do Centro de Energia Nuclear na Agricultura , Piracicaba, SP; Brazil)

    2005-01-01

    In this study fish were used as bioindicators of environmental contamination. The species were collected in Piracicaba River, Sao Paulo state, Brazil and the toxic elements concentrations were determined in muscle tissue and viscus (liver, intestine and stomach) by Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SR-TXRF). Were determined the elements Ti, Cr, Mn, Fe, Ni, Cu, Zn and Ba. The results were compared with values established by Brazilian Legislation for general food. The elements concentrations evidenced potential risk to human health and environmental quality alteration of the studied area. The measurements were realized at the 'Laboratorio Nacional de Luz Sincrotron' (LNLS) located in Campinas, Sao Paulo State, Brazil. (author)

  7. Fish samples as bioindicator of environmental quality: synchrotron radiation total reflection X-ray fluorescence analysis (SR-TXRF)

    Energy Technology Data Exchange (ETDEWEB)

    Vives, Ana Elisa Sirito de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Moreira, Silvana [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: Silvana@fec.unicamp.br; Brienza, Sandra Maria Boscolo [Universidade Metodista de Piracicaba (UNIMEP), SP (Brazil). Faculdade de Ciencias Matematicas, da Natureza e de Tecnologia da Informacao]. E-mail: sbrienza@unimep.br; Zucchi, Orgheda Luiza Araujo Domingues [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br; Nascimento Filho, Virgilio Franco do [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)]. E-mail: virgilio@cena.usp.br

    2005-07-01

    In this study fish were used as bioindicators of environmental contamination. The species were collected in Piracicaba River, Sao Paulo state, Brazil and the toxic elements concentrations were determined in muscle tissue and viscus (liver, intestine and stomach) by Synchrotron Radiation Total Reflection X-Ray Fluorescence Analysis (SR-TXRF). Were determined the elements Ti, Cr, Mn, Fe, Ni, Cu, Zn and Ba. The results were compared with values established by Brazilian Legislation for general food. The elements concentrations evidenced potential risk to human health and environmental quality alteration of the studied area. The measurements were realized at the 'Laboratorio Nacional de Luz Sincrotron' (LNLS) located in Campinas, Sao Paulo State, Brazil. (author)

  8. Improved surface quality of anisotropically etched silicon {111} planes for mm-scale optics

    International Nuclear Information System (INIS)

    Cotter, J P; Hinds, E A; Zeimpekis, I; Kraft, M

    2013-01-01

    We have studied the surface quality of millimetre-scale optical mirrors produced by etching CZ and FZ silicon wafers in potassium hydroxide to expose the {111} planes. We find that the FZ surfaces have four times lower noise power at spatial frequencies up to 500 mm −1 . We conclude that mirrors made using FZ wafers have higher optical quality. (technical note)

  9. Investigation and Evaluation on Influence of Machining (CNC Conditions on Surface Quality of Paulownia Wood

    Directory of Open Access Journals (Sweden)

    Mohammad Aghajani

    2012-01-01

    Full Text Available The aim of this study was to investigate the effective factors on surface quality of paulownia wood during machining by advanced computer numerical controled (CNC machine. For this aim paulownia logs were provided and were converted to proper sizes (2.5 x 10 x 15 cm and then air dried. The Variable of this study were cutting speed (8.37 and 15.07 m/s, feeding rate (6 and 12 m/min, cutting depth (1and 5 mm, cutting method (down and up-milling and cutting pattern (tangential and radial. Roughness of cut specimens edge were evaluated by profilometer method according to ISO 13565 standard. For evaluation of surface quality, average roughness (Ra, maximum roughness (R max, valley roughness (Rv and peak roughness (Rp were used. Degrees of effectiveness of the parameters were evaluated by fractional factorial design as completely random design at confidence level of 95%. The result showed that cutting speed, cutting method and feed rate are influencive factors on surface quality of machined specimens and their effects were significant. With increasing cutting speed and decreasing feeding rate the roughness decreased and surface quality improved. In up-milling cutting method, degree of roughness was higher and consequently surface quality was inferior. It is to be noted that cutting method in comparison to other factors had the high influence on surface quality. The rest variables did now have independent influence on surface quality at 95% Confidence level. This study for achieving the optimum surface quality recommends that cutting speed of 15.07 m/s, feeding rate of 6 m/min, cutting method of down-milling and cutting depth of 1 mm for tangential cross section.

  10. The quality of school lunch consumed reflects overall eating patterns in 11-16-year-old schoolchildren in Finland.

    Science.gov (United States)

    Tilles-Tirkkonen, Tanja; Pentikäinen, Saara; Lappi, Jenni; Karhunen, Leila; Poutanen, Kaisa; Mykkänen, Hannu

    2011-12-01

    To explore how the quality of school lunch consumed reflected overall eating patterns in school-aged children. Children filled in an Internet-based questionnaire about their eating patterns. The children were then divided into balanced and imbalanced school lunch eaters on the basis of their responses in the questionnaire. A balanced school lunch consisted of, by the definition used in the present study, a main dish, salad and bread. Eleven primary schools and one middle school in eastern Finland. A total of 531 schoolchildren (247 boys and 284 girls) aged 11-16 years. The school lunch was balanced in 46·5% of children. Eating a balanced school lunch was associated with overall healthier eating patterns outside school. Children who ate a balanced school lunch had more regular meal times and consumed healthier snacks. They ate fruit or berries and vegetables, dairy products and wholegrain foods more often, consumed fewer salty snacks, pizzas, meat pies and drank fewer soft drinks and energy drinks. Their eating patterns at home were also healthier, with vegetables being offered at every family dinner and fruit being offered daily, whereas soft drinks were offered seldom. The choices made by children in their school lunch reflect the overall eating patterns among school-aged children. Eating a balanced school lunch is associated with more regular meal patterns, the availability of healthier foods at home and an overall healthier diet, suggesting that healthy eating patterns are learnt at home.

  11. Reflectance Modeling

    Science.gov (United States)

    Smith, J. A.; Cooper, K.; Randolph, M.

    1984-01-01

    A classical description of the one dimensional radiative transfer treatment of vegetation canopies was completed and the results were tested against measured prairie (blue grama) and agricultural canopies (soybean). Phase functions are calculated in terms of directly measurable biophysical characteristics of the canopy medium. While the phase functions tend to exhibit backscattering anisotropy, their exact behavior is somewhat more complex and wavelength dependent. A Monte Carlo model was developed that treats soil surfaces with large periodic variations in three dimensions. A photon-ray tracing technology is used. Currently, the rough soil surface is described by analytic functions and appropriate geometric calculations performed. A bidirectional reflectance distribution function is calculated and, hence, available for other atmospheric or canopy reflectance models as a lower boundary condition. This technique is used together with an adding model to calculate several cases where Lambertian leaves possessing anisotropic leaf angle distributions yield non-Lambertian reflectance; similar behavior is exhibited for simulated soil surfaces.

  12. Quality of surface waters in the lower Columbia River Basin

    Science.gov (United States)

    Santos, John F.

    1965-01-01

    This report, made during 1959-60, provides reconnaissance data on the quality of waters in the lower Columbia River basin ; information on present and future water problems in the basin; and data that can be employed both in water-use studies and in planning future industrial, municipal, and agricultural expansion within this area. The lower Columbia River basin consists of approximately 46,000 square miles downstream from the confluence of the Snake and Columbia Rivers The region can be divided into three geographic areas. The first is the heavily forested, sparsely populated mountain regions in which quality of water in general is related to geologic and climatological factors. The second is a semiarid plateau east of the Cascade Mountains; there differences in geology and precipitation, together with more intensive use of available water for irrigation, bring about marked differences in water quality. The third is the Willamette-Puget trough area in which are concentrated most of the industry and population and in which water quality is influenced by sewage and industrial waste disposal. The majority of the streams in the lower Columbia River basin are calcium magnesium bicarbonate waters. In general, the rivers rising in the. Coast Range and on the west slope of the Cascade Range contain less than 100 parts per million of dissolved solids, and hardness of the water is less than 50 parts per million. Headwater reaches of the streams on the east slope of the Cascade Range are similar to those on the west slope; but, downstream, irrigation return flows cause the dissolved-solids content and hardness to increase. Most of the waters, however, remain calcium magnesium bicarbonate in type. The highest observed dissolved-solids concentrations and also some changes in chemical composition occur in the streams draining the more arid parts of the area. In these parts, irrigation is chiefly responsible for increasing the dissolved-solids concentration and altering the

  13. Application of Sol-Gel Method as a Protective Layer on a Specular Reflective Surface for Secondary Reflector in a Solar Receiver

    Energy Technology Data Exchange (ETDEWEB)

    Afrin, Samia; Dagdelen, John; Ma, Zhiwen; Kumar, Vinod

    2017-01-01

    Highly-specular reflective surfaces that can withstand elevated-temperatures are desirable for many applications including reflective heat shielding in solar receivers and secondary reflectors, which can be used between primary concentrators and heat collectors. A high-efficiency, high-temperature solar receiver design based on arrays of cavities needs a highly-specular reflective surface on its front section to help sunlight penetrate into the absorber tubes for effective flux spreading. Since this application is for high-temperature solar receivers, this surface needs to be durable and to maintain its optical properties through the usable life. Degradation mechanisms associated with elevated temperatures and thermal cycling, which include cracking, delamination, corrosion/oxidation, and environmental effects, could cause the optical properties of surfaces to degrade rapidly in these conditions. Protected mirror surfaces for these applications have been tested by depositing a thin layer of SiO2 on top of electrodeposited silver by means of the sol-gel method. To obtain an effective thin film structure, this sol-gel procedure has been investigated extensively by varying process parameters that affect film porosity and thickness. Endurance tests have been performed in a furnace at 150 degrees C for thousands of hours. This paper presents the sol-gel process for intermediate-temperature specular reflective coatings and provides the long-term reliability test results of sol-gel protected silver-coated surfaces.

  14. Study on the cloud detection of GOCI by using the simulated surface reflectance from BRDF-model for the land application and meteorological utilization

    Science.gov (United States)

    Kim, Hye-Won; Yeom, Jong-Min; Woo, Sun-Hee; Chae, Tae-Byeong

    2016-04-01

    COMS (Communication, Ocean, and Meteorological Satellite) was launched at French Guiana Kourou space center on 27 June 2010. Geostationary Ocean Color Imager (GOCI), which is the first ocean color geostationary satellite in the world for observing the ocean phenomena, is able to obtain the scientific data per an hour from 00UTC to 07UTC. Moreover, the spectral channels of GOCI would enable not only monitoring for the ocean, but for extracting the information of the land surface over the Korean Peninsula, Japan, and Eastern China. Since it is extremely important to utilize GOCI data accurately for the land application, cloud pixels over the surface have to be removed. Unfortunately, infra-red (IR) channels that can easily detect the water vapor with the cloud top temperature, are not included in the GOCI sensor. In this paper, the advanced cloud masking algorithm will be proposed with visible and near-IR (NIR) bands that are within GOCI bands. The main obstacle of cloud masking with GOCI is how to handle the high variable surface reflectance, which is mainly depending on the solar zenith angle. In this study, we use semi-empirical BRDF model to simulate the surface reflectance by using 16 day composite cloudy free image. When estimating the simulated surface reflectance, same geometry for GOCI observation was applied. The simulated surface reflectance is used to discriminate cloud areas especially for the thin cloud and shows more reasonable result than original threshold methods.

  15. Surface water-quality activities of the U.S. Geological Survey in New England

    Science.gov (United States)

    Huntington, Thomas G.

    2016-03-23

    The U.S. Geological Survey (USGS) collaborates with a variety of Federal, State, local, and tribal partners on scientific projects to provide reliable and impartial water-quality data and interpretation to resource managers, planners, stakeholders, and the general public. The themes related to surface water quality include the following:

  16. Remote sensing as a surface water quality monitoring support in the semiarid region of Brazil

    OpenAIRE

    Fernando Bezerra Lopes

    2013-01-01

    The contamination of surface water bodies due to antropic action has made water ever more scarce. Knowledge of the water quality is essential to determine instruments for it's management . Monitoring water quality in huge areas requires a high number of saimples for water quality control. This fact, allied to the high costs of water analysis, limits the evaluation that can be made of continental waters. Even though in later years geoprocessing and remote sensin...

  17. Conductivity as an indicator of surface water quality in the proximity ...

    African Journals Online (AJOL)

    2015-10-05

    Oct 5, 2015 ... FeCr smelting did not significantly impact surface water quality, but that surface run-off and/or groundwater leaching ... (EIAs) were required, or for older FeCr smelters during the .... then used for the determination of conductivity with a Hanna ... significant differences in the conductivity values measured at.

  18. MODELING OF QUALITY FORMATION OF PIG IRON BILLET SURFACE AT WIRE BRUSH MILLING

    Directory of Open Access Journals (Sweden)

    I. L. Barshaj

    2009-01-01

    Full Text Available Formation of topography, geometrical structure and micro-hardness of pig iron billet surface is considered in the paper. Mathematical models pertaining to formation of the above-mentioned characteristics of surface quality according to parameters of machining regime have been developed on the basis of the executed investigations.

  19. Onboard tagging for real-time quality assessment of photoplethysmograms acquired by a wireless reflectance pulse oximeter.

    Science.gov (United States)

    Li, Kejia; Warren, Steve; Natarajan, Balasubramaniam

    2012-02-01

    Onboard assessment of photoplethysmogram (PPG) quality could reduce unnecessary data transmission on battery-powered wireless pulse oximeters and improve the viability of the electronic patient records to which these data are stored. These algorithms show promise to increase the intelligence level of former "dumb" medical devices: devices that acquire and forward data but leave data interpretation to the clinician or host system. To this end, the authors have developed a unique onboard feature detection algorithm to assess the quality of PPGs acquired with a custom reflectance mode, wireless pulse oximeter. The algorithm uses a Bayesian hypothesis testing method to analyze four features extracted from raw and decimated PPG data in order to determine whether the original data comprise valid PPG waveforms or whether they are corrupted by motion or other environmental influences. Based on these results, the algorithm further calculates heart rate and blood oxygen saturation from a "compact representation" structure. PPG data were collected from 47 subjects to train the feature detection algorithm and to gauge their performance. A MATLAB interface was also developed to visualize the features extracted, the algorithm flow, and the decision results, where all algorithm-related parameters and decisions were ascertained on the wireless unit prior to transmission. For the data sets acquired here, the algorithm was 99% effective in identifying clean, usable PPGs versus nonsaturated data that did not demonstrate meaningful pulsatile waveshapes, PPGs corrupted by motion artifact, and data affected by signal saturation.

  20. Radiative transfer in shrub savanna sites in Niger: preliminary results from HAPEX-Sahel. 1. Modelling surface reflectance using a geometric-optical approach

    International Nuclear Information System (INIS)

    Franklin, J.; Duncan, J.; Huete, A.R.; Leeuwen, W.J.D. van; Li, X.; Bégué, A.

    1994-01-01

    To use optical remote sensing to monitor land surface-climate interactions over large areas, algorithms must be developed to relate multispectral measurements to key variables controlling the exchange of matter (water, carbon dioxide) and energy between the land surface and the atmosphere. The proportion of the ground covered by vegetation and the interception of photosynthetically active radiation (PAR) by vegetation are examples of two variables related to evapotranspiration and primary production, respectively. An areal-proportion model of the multispectral reflectance of shrub savanna, composed of scattered shrubs with a grass, forb or soil understory, predicted the reflectance of two 0.5 km 2 sites as the area-weighted average of the shrub and understory or ‘background’ reflectances. Although the shaded crown and shaded background have darker reflectances, ignoring them in the area-weighted model is not serious when shrub cover is low and solar zenith angle is small. A submodel predicted the reflectance of the shrub crown as a function of the foliage reflectance and amount of plant material within the crown, and the background reflectance scattered or transmitted through canopy gaps (referred to as a soil—plant ‘spectral interaction’ term). One may be able to combine these two models to estimate both the fraction of vegetation cover and interception of PAR by green vegetation in a shrub savanna. (author)

  1. Fitness function and nonunique solutions in x-ray reflectivity curve fitting: crosserror between surface roughness and mass density

    International Nuclear Information System (INIS)

    Tiilikainen, J; Bosund, V; Mattila, M; Hakkarainen, T; Sormunen, J; Lipsanen, H

    2007-01-01

    Nonunique solutions of the x-ray reflectivity (XRR) curve fitting problem were studied by modelling layer structures with neural networks and designing a fitness function to handle the nonidealities of measurements. Modelled atomic-layer-deposited aluminium oxide film structures were used in the simulations to calculate XRR curves based on Parratt's formalism. This approach reduced the dimensionality of the parameter space and allowed the use of fitness landscapes in the study of nonunique solutions. Fitness landscapes, where the height in a map represents the fitness value as a function of the process parameters, revealed tracks where the local fitness optima lie. The tracks were projected on the physical parameter space thus allowing the construction of the crosserror equation between weakly determined parameters, i.e. between the mass density and the surface roughness of a layer. The equation gives the minimum error for the other parameters which is a consequence of the nonuniqueness of the solution if noise is present. Furthermore, the existence of a possible unique solution in a certain parameter range was found to be dependent on the layer thickness and the signal-to-noise ratio

  2. Hyperspectral sensing for turbid water quality monitoring in freshwater rivers: Empirical relationship between reflectance and turbidity and total solids.

    Science.gov (United States)

    Wu, Jiunn-Lin; Ho, Chung-Ru; Huang, Chia-Ching; Srivastav, Arun Lal; Tzeng, Jing-Hua; Lin, Yao-Tung

    2014-11-28

    Total suspended solid (TSS) is an important water quality parameter. This study was conducted to test the feasibility of the band combination of hyperspectral sensing for inland turbid water monitoring in Taiwan. The field spectral reflectance in the Wu river basin of Taiwan was measured with a spectroradiometer; the water samples were collected from the different sites of the Wu river basin and some water quality parameters were analyzed on the sites (in situ) as well as brought to the laboratory for further analysis. To obtain the data set for this study, 160 in situ sample observations were carried out during campaigns from August to December, 2005. The water quality results were correlated with the reflectivity to determine the spectral characteristics and their relationship with turbidity and TSS. Furthermore, multiple-regression (MR) and artificial neural network (ANN) were used to model the transformation function between TSS concentration and turbidity levels of stream water, and the radiance measured by the spectroradiometer. The value of the turbidity and TSS correlation coefficient was 0.766, which implies that turbidity is significantly related to TSS in the Wu river basin. The results indicated that TSS and turbidity are positively correlated in a significant way across the entire spectrum, when TSS concentration and turbidity levels were under 800 mg·L(-1) and 600 NTU, respectively. Optimal wavelengths for the measurements of TSS and turbidity are found in the 700 and 900 nm range, respectively. Based on the results, better accuracy was obtained only when the ranges of turbidity and TSS concentration were less than 800 mg·L(-1) and less than 600 NTU, respectively and used rather than using whole dataset (R(2) = 0.93 versus 0.88 for turbidity and R(2) = 0.83 versus 0.58 for TSS). On the other hand, the ANN approach can improve the TSS retrieval using MR. The accuracy of TSS estimation applying ANN (R(2) = 0.66) was better than with the MR approach (R

  3. Hyperspectral Sensing for Turbid Water Quality Monitoring in Freshwater Rivers: Empirical Relationship between Reflectance and Turbidity and Total Solids

    Directory of Open Access Journals (Sweden)

    Jiunn-Lin Wu

    2014-11-01

    Full Text Available Total suspended solid (TSS is an important water quality parameter. This study was conducted to test the feasibility of the band combination of hyperspectral sensing for inland turbid water monitoring in Taiwan. The field spectral reflectance in the Wu river basin of Taiwan was measured with a spectroradiometer; the water samples were collected from the different sites of the Wu river basin and some water quality parameters were analyzed on the sites (in situ as well as brought to the laboratory for further analysis. To obtain the data set for this study, 160 in situ sample observations were carried out during campaigns from August to December, 2005. The water quality results were correlated with the reflectivity to determine the spectral characteristics and their relationship with turbidity and TSS. Furthermore, multiple-regression (MR and artificial neural network (ANN were used to model the transformation function between TSS concentration and turbidity levels of stream water, and the radiance measured by the spectroradiometer. The value of the turbidity and TSS correlation coefficient was 0.766, which implies that turbidity is significantly related to TSS in the Wu river basin. The results indicated that TSS and turbidity are positively correlated in a significant way across the entire spectrum, when TSS concentration and turbidity levels were under 800 mg·L−1 and 600 NTU, respectively. Optimal wavelengths for the measurements of TSS and turbidity are found in the 700 and 900 nm range, respectively. Based on the results, better accuracy was obtained only when the ranges of turbidity and TSS concentration were less than 800 mg·L−1 and less than 600 NTU, respectively and used rather than using whole dataset (R2 = 0.93 versus 0.88 for turbidity and R2 = 0.83 versus 0.58 for TSS. On the other hand, the ANN approach can improve the TSS retrieval using MR. The accuracy of TSS estimation applying ANN (R2 = 0.66 was better than with the MR

  4. Surface characterization of selected polymer thin films by total-reflection x-ray fluorescence spectroscopy and x-ray reflectivity

    International Nuclear Information System (INIS)

    Innis, Vallerie Ann A.

    2006-01-01

    Development of available x-ray characterizations tools for grazing incidence techniques was done to be able to probe nano-size thin films. Alignment of a Philips x-ray powder diffractometer was improved to let it perform as an x-ray reflectometer. X-ray reflectometry was coupled with total-reflection x-ray fluorescence spectroscopy. Evaluation of the performance of this grazing incidence techniques was done by preparing polymer thin films of carboxymethylcellulose, carrageenan and polyvinylpyrrolidone (PVP). The thickness of the films were varied by varying the process parameters such as concentration, spin speed and spin time. Angle-dispersive total-reflection x-ray fluorescence spectroscopy profiles of three films showed film formation only in carrageenan and PVP. For both carrageenan and PVP, an increase in concentration yielded a corresponding increase in intensity of the fluorescent or scattered peaks. XRR profiles of carrageenan thin films yielded a mean value for the critical angle close to quartz substrate. Thickness measurements of the prepared carrageenan thin films showed that concentration was the main determinant for final film thickness over the other process parameters. Sulfur fluorescent intensity derived from the TXRF measurement showed a linear relationship with the measured thickness by XRR. For PVP, measured critical angle is lower than quartz. Poor adhesion of the polymer onto the substrate yielded a limited number of thickness measurements made from the XRR profiles. (Author)

  5. Derivation of Land Surface Albedo at High Resolution by Combining HJ-1A/B Reflectance Observations with MODIS BRDF Products

    Directory of Open Access Journals (Sweden)

    Bo Gao

    2014-09-01

    Full Text Available Land surface albedo is an essential parameter for monitoring global/regional climate and land surface energy balance. Although many studies have been conducted on global or regional land surface albedo using various remote sensing data over the past few decades, land surface albedo product with a high spatio–temporal resolution is currently very scarce. This paper proposes a method for deriving land surface albedo with a high spatio–temporal resolution (space: 30 m and time: 2–4 days. The proposed method works by combining the land surface reflectance data at 30 m spatial resolution obtained from the charge-coupled devices in the Huanjing-1A and -1B (HJ-1A/B satellites with the Moderate Resolution Imaging Spectroradiometer (MODIS land surface bidirectional reflectance distribution function (BRDF parameters product (MCD43A1, which is at a spatial resolution of 500 m. First, the land surface BRDF parameters for HJ-1A/B land surface reflectance with a spatial–temporal resolutions of 30 m and 2–4 day are calculated on the basis of the prior knowledge from the MODIS BRDF product; then, the calculated high resolution BRDF parameters are integrated over the illuminating/viewing hemisphere to produce the white- and black-sky albedos at 30 m resolution. These results form the basis for the final land surface albedo derivation by accounting for the proportion of direct and diffuse solar radiation arriving at the ground. The albedo retrieved by this novel method is compared with MODIS land surface albedo products, as well as with ground measurements. The results show that the derived land surface albedo during the growing season of 2012 generally achieved a mean absolute accuracy of ±0.044, and a root mean square error of 0.039, confirming the effectiveness of the newly proposed method.

  6. Land Surface Process and Air Quality Research and Applications at MSFC

    Science.gov (United States)

    Quattrochi, Dale; Khan, Maudood

    2007-01-01

    This viewgraph presentation provides an overview of land surface process and air quality research at MSFC including atmospheric modeling and ongoing research whose objective is to undertake a comprehensive spatiotemporal analysis of the effects of accurate land surface characterization on atmospheric modeling results, and public health applications. Land use maps as well as 10 meter air temperature, surface wind, PBL mean difference heights, NOx, ozone, and O3+NO2 plots as well as spatial growth model outputs are included. Emissions and general air quality modeling are also discussed.

  7. Relation between Cutting Surface Quality and Alloying Element Contents when Using a CO2 Laser

    Directory of Open Access Journals (Sweden)

    J. Litecká

    2011-01-01

    Full Text Available This paper deals with the influence of material content on changes in the quality parameters of the cutting surface when cutting with a laser. The study focuses on experiments to find the effect of material structure and cutting parameters on surface roughness, Vickers microhardness and precision of laser cutting. The experimental results are shown in graphs which illustrate the suitability of materials for achieving required cutting surface quality parameters. These results can be used for optimizing production in practical applications using a laser cutting machine.

  8. Biological methods used to assess surface water quality

    Directory of Open Access Journals (Sweden)

    Szczerbiñska Natalia

    2015-12-01

    Full Text Available In accordance with the guidelines of the Water Framework Directive 2000/60 (WFD, both ecological and chemical statuses determine the assessment of surface waters. The profile of ecological status is based on the analysis of various biological components, and physicochemical and hydromorphological indicators complement this assessment. The aim of this article is to present the biological methods used in the assessment of water status with a special focus on bioassay, as well as to provide a review of methods of monitoring water status. Biological test methods include both biomonitoring and bioanalytics. Water biomonitoring is used to assess and forecast the status of water. These studies aim to collect data on water pollution and forecast its impact. Biomonitoring uses organisms which are characterized by particular vulnerability to contaminants. Bioindicator organisms are algae, fungi, bacteria, larval invertebrates, cyanobacteria, macroinvertebrates, and fish. Bioanalytics is based on the receptors of contaminants that can be biologically active substances. In bioanalytics, biosensors such as viruses, bacteria, antibodies, enzymes, and biotests are used to assess degrees of pollution.

  9. Investigating the Effect of Approach Angle and Nose Radius on Surface Quality of Inconel 718

    Science.gov (United States)

    Kumar, Sunil; Singh, Dilbag; Kalsi, Nirmal S.

    2017-11-01

    This experimental work presents a surface quality evaluation of a Nickel-Cr-Fe based Inconel 718 superalloy, which has many applications in the aero engine and turbine components. However, during machining, the early wear of tool leads to decrease in surface quality. The coating on cutting tool plays a significant role in increasing the wear resistance and life of the tool. In this work, the aim is to study the surface quality of Inconel 718 with TiAlN-coated carbide tools. Influence of various geometrical parameters (tool nose radius, approach angle) and machining variables (cutting velocity, feed rate) on the quality of machined surface (surface roughness) was determined by using central composite design (CCD) matrix. The mathematical model of the same was developed. Analysis of variance was used to find the significance of the parameters. Results showed that the tool nose radius and feed were the main active factors. The present experiment accomplished that TiAlN-coated carbide inserts result in better surface quality as compared with uncoated carbide inserts.

  10. Determination of Groundwater and Surface Water Qualities at Si Racha, Chon Buri

    International Nuclear Information System (INIS)

    Wangsawang, Jarinee; Naenorn, Warinlada; Khuntong, Soontree; Wongsorntam, Krirk; Udomsomporn, Suchin

    2011-06-01

    Full text: Groundwater (13 wells) and surface water (7 ponds) at Si Racha, Chon Buri province were collected for measurement of water qualities and radionuclides. The water qualities included physical and chemical analysis such as pH, EC, TS, TDS, TSS, TKN, total phosphate, BOD, COD, total hardness and FOG based on standard methods for examination of water and wastewater. Heavy metals (Cd, Cu, Cr, Fe, Mn, Ni and Zn) were analyzed by ICP-AES while total coliform was determined by Multiple Tube Methods. Moreover, radionuclides were analyzed by gamma spectrometer and gross beta and gross alpha were obtained from low background gas proportional counter. Values of most parameters in groundwater were below water qualities standards but all parameters in surface water samples were exceeded water qualities standards. It was found that all radionuclides in water samples were originated from natural uranium and thorium series. The data obtained enabled evaluation of pollutants in groundwater and surface water

  11. Cross-calibration of Medium Resolution Earth Observing Satellites by Using EO-1 Hyperion-derived Spectral Surface Reflectance from "Lunar Cal Sites"

    Science.gov (United States)

    Ungar, S.

    2017-12-01

    Over the past 3 years, the Earth Observing-one (EO-1) Hyperion imaging spectrometer was used to slowly scan the lunar surface at a rate which results in up to 32X oversampling to effectively increase the SNR. Several strategies, including comparison against the USGS RObotic Lunar Observatory (ROLO) mode,l are being employed to estimate the absolute and relative accuracy of the measurement set. There is an existing need to resolve discrepancies as high as 10% between ROLO and solar based calibration of current NASA EOS assets. Although the EO-1 mission was decommissioned at the end of March 2017, the development of a well-characterized exoatmospheric spectral radiometric database, for a range of lunar phase angles surrounding the fully illuminated moon, continues. Initial studies include a comprehensive analysis of the existing 17-year collection of more than 200 monthly lunar acquisitions. Specific lunar surface areas, such as a lunar mare, are being characterized as potential "lunar calibration sites" in terms of their radiometric stability in the presence of lunar nutation and libration. Site specific Hyperion-derived lunar spectral reflectance are being compared against spectrographic measurements made during the Apollo program. Techniques developed through this activity can be employed by future high-quality orbiting imaging spectrometers (such as HyspIRI and EnMap) to further refine calibration accuracies. These techniques will enable the consistent cross calibration of existing and future earth observing systems (spectral and multi-spectral) including those that do not have lunar viewing capability. When direct lunar viewing is not an option for an earth observing asset, orbiting imaging spectrometers can serve as transfer radiometers relating that asset's sensor response to lunar values through near contemporaneous observations of well characterized stable CEOS test sites. Analysis of this dataset will lead to the development of strategies to ensure more

  12. Urban Surface Water Quality, Flood Water Quality and Human Health Impacts in Chinese Cities. What Do We Know?

    Directory of Open Access Journals (Sweden)

    Yuhan Rui

    2018-02-01

    Full Text Available Climate change and urbanization have led to an increase in the frequency of extreme water related events such as flooding, which has negative impacts on the environment, economy and human health. With respect to the latter, our understanding of the interrelationship between flooding, urban surface water and human health is still very limited. More in-depth research in this area is needed to further strengthen the process of planning and implementation of responses to mitigate the negative health impacts of flooding in urban areas. The objective of this paper is to assess the state of the research on the interrelationship between surface water quality, flood water quality and human health in urban areas based on the published literature. These insights will be instrumental in identifying and prioritizing future research needs in this area. In this study, research publications in the domain of urban flooding, surface water quality and human health were collated using keyword searches. A detailed assessment of these publications substantiated the limited number of publications focusing on the link between flooding and human health. There was also an uneven geographical distribution of the study areas, as most of the studies focused on developed countries. A few studies have focused on developing countries, although the severity of water quality issues is higher in these countries. The study also revealed a disparity of research in this field across regions in China as most of the studies focused on the populous south-eastern region of China. The lack of studies in some regions has been attributed to the absence of flood water quality monitoring systems which allow the collection of real-time water quality monitoring data during flooding in urban areas. The widespread implementation of cost effective real-time water quality monitoring systems which are based on the latest remote or mobile phone based data acquisition techniques is recommended

  13. Monitoring surface water quality using social media in the context of citizen science

    Science.gov (United States)

    Zheng, Hang; Hong, Yang; Long, Di; Jing, Hua

    2017-02-01

    Surface water quality monitoring (SWQM) provides essential information for water environmental protection. However, SWQM is costly and limited in terms of equipment and sites. The global popularity of social media and intelligent mobile devices with GPS and photography functions allows citizens to monitor surface water quality. This study aims to propose a method for SWQM using social media platforms. Specifically, a WeChat-based application platform is built to collect water quality reports from volunteers, which have been proven valuable for water quality monitoring. The methods for data screening and volunteer recruitment are discussed based on the collected reports. The proposed methods provide a framework for collecting water quality data from citizens and offer a primary foundation for big data analysis in future research.

  14. Use of MODIS Terra Imagery to Estimate Surface Water Quality Standards, Using Lake Thonotosassa, Florida, as a Case Study

    Science.gov (United States)

    Moreno, Max J.; Al-Hamdan, Mohammad Z.; Estes, Maurice G., Jr.; Rickman, Douglas L.

    2010-01-01

    Lake Thonotosassa is a highly eutrophied lake located in an area with rapidly growing population in the Tampa Bay watershed, Florida. The Florida Administrative Code has designated its use for "recreation, propagation and maintenance of a healthy, well-balanced population of fish and wildlife." Although this lake has been the subject of efforts to improve water quality since 1970, overall water quality has remained below the acceptable state standards, and has a high concentration of nutrients. This condition is of great concern to public health since it has favored episodic blooms of Cyanobacteria. Some Cyanobacterial species release toxins that can reach humans through drinking water, fish consumption, and direct contact with contaminated water. The lake has been historically popular for fishing and water sports, and its overflow water drains into the Hillsborough River, the main supply of municipal water for the City of Tampa, this explains why it has being constantly monitored in situ for water quality by the Environmental Protection Commission of Hillsborough County (EPC). Advances in remote sensing technology, however, open the possibility of facilitating similar types of monitoring in this and similar lakes, further contributing to the implementation of surveillance systems that would benefit not just public health, but also tourism and ecosystems. Although traditional application of this technology to water quality has been focused on much larger coastal water bodies like bays and estuaries, this study evaluates the feasibility of its application on a 46.6 km2 freshwater lake. Using surface reflectance products from Moderate-Resolution Imaging Spectroradiometer (MODIS) Terra, this study evaluates associations between remotely sensed data and in situ data from the EPC. The parameters analyzed are the surface water quality standards used by the State of Florida and general indicators of trophic status.

  15. Mapping lithosphere thickness beneath the Southern Caribbean and Venezuela using body wave reflectivity and surface wave tomography

    Science.gov (United States)

    Masy, J.; Niu, F.; Levander, A.; Schmitz, M.

    2012-12-01

    The Caribbean (CAR) and South American (SA) plate boundary in Venezuela is a broad zone of diffuse deformation and faulting. GPS measurements indicate that the CAR is moving approximately 2 cm/yr respect to SA, parallel to the strike slip fault system in the east, but with an oblique convergence component in the west (Weber et al., 2001). Along the central and eastern Venezuela coast, most of the motion is accommodated by both transpression and transtension along the right lateral strike-slip San Sebastian- El Pilar fault system. The main tectonic features of the area include accretionary wedges and coastal thrust belts with their associated foreland basins (e.g. Sierra del Interior and Espino Graben). Southern of the plate boundary is located the Guayana Shield, which is part of the Amazonian Craton, and is an elevated plain consisting of Precambrian rocks. BOLIVAR (Broadband Onshore-Offshore Lithospheric Investigation of Venezuela and the Antilles Arc Region) was a multidisciplinary, international investigation to determine the evolution of the CAR-SA plate boundary (Levander et al., 2006) that included a 47 station broadband seismic array to complement the 40 station Venezuelan national array operated by FUNVISIS. The goal of this study is to map out lithosphere thickness across the region in order to understand its role for the various types of deformations observed at surface. We combined surface wave tomography and body wave reflectivity to locate the depth of the lithosphere-asthenosphere boundary (LAB). To generate a coherent 3D reflectivity volume of the study area, we used both P- and S-wave receiver-function data, as well as the ScS reverberation records of two deep earthquakes occurring in South America. We also measured Rayleigh phase velocities in the frequency range of 20-100 s using the two plane-wave method to remove multi-pathing effects (Forsyth and Li, 2005). Finite-frequency kernels were computed for a total of 63 teleseismic events to improve

  16. Vapor phase treatment–total reflection X-ray fluorescence for trace elemental analysis of silicon wafer surface

    International Nuclear Information System (INIS)

    Takahara, Hikari; Mori, Yoshihiro; Shibata, Harumi; Shimazaki, Ayako; Shabani, Mohammad B.; Yamagami, Motoyuki; Yabumoto, Norikuni; Nishihagi, Kazuo; Gohshi, Yohichi

    2013-01-01

    Vapor phase treatment (VPT) was under investigation by the International Organization for Standardization/Technical Committee 201/Working Group 2 (ISO/TC201/WG2) to improve the detection limit of total reflection X-ray fluorescence spectroscopy (TXRF) for trace metal analysis of silicon wafers. Round robin test results have confirmed that TXRF intensity increased by VPT for intentional contamination with 5 × 10 9 and 5 × 10 10 atoms/cm 2 Fe and Ni. The magnification of intensity enhancement varied greatly (1.2–4.7 in VPT factor) among the participating laboratories, though reproducible results could be obtained for average of mapping measurement. SEM observation results showed that various features, sizes, and surface densities of particles formed on the wafer after VPT. The particle morphology seems to have some impact on the VPT efficiency. High resolution SEM observation revealed that a certain number of dots with SiO 2 , silicate and/or carbon gathered to form a particle and heavy metals, Ni and Fe in this study were segregated on it. The amount and shape of the residue should be important to control VPT factor. - Highlights: • This paper presents a summary of study results of VPT–TXRF using ISO/TC201/WG2. • Our goal is to analyze the trace metallic contamination on silicon wafer with concentrations below 1 × 10 10 atoms/cm 2 . • The efficiency and mechanism of VPT are discussed under several round robin tests and systematic studies

  17. Surface Quality Improvement of AA6060 Aluminum Extruded Components through Liquid Nitrogen Mold Cooling

    Directory of Open Access Journals (Sweden)

    Andrea Francesco Ciuffini

    2018-06-01

    Full Text Available 6xxx aluminum alloys are suitable for the realization of both structural applications and architectural decorative elements, thanks to the combination of high corrosion resistance and good surface finish. In areas where the aesthetic aspects are fundamental, further improvements in surface quality are significant. The cooling of the extrusion mold via internal liquid nitrogen fluxes is emerging as an important innovation in aluminum extrusion. Nowadays, this innovation is providing a large-scale solution to obtain high quality surface finishes in extruded aluminum semi-finished products. These results are also coupled to a significant increase in productivity. The aim of the work is to compare the surface quality of both cooled liquid nitrogen molds and classically extruded products. In this work, adhesion phenomena, occurring during the extrusion between the mold and the flowing material, have been detected as the main causes of the presence of surface defects. The analysis also highlighted a strong increase in the surface quality whenever the extrusion mold was cooled with liquid nitrogen fluxes. This improvement has further been confirmed by an analysis performed on the finished products, after painting and chromium plating. This work on the AA6060 alloy has moreover proceeded to roughness measurements and metallographic analyses, to investigate the eventual occurrence of other possible benefits stemming from this new extrusion mold cooling technology.

  18. Influence of aerosols and surface reflectance on satellite NO2 retrieval: seasonal and spatial characteristics and implications for NOx emission constraints

    NARCIS (Netherlands)

    Lin, J.T.; Liu, M.Y.; Xin, J.Y.; Boersma, K.F.; Spurr, R.; Zhang, Q.; Martin, R.

    2015-01-01

    Satellite retrievals of vertical column densities (VCDs) of tropospheric nitrogen dioxide (NO2) normally do not explicitly account for aerosol optical effects and surface reflectance anisotropy that vary with space and time. Here, we conduct an improved retrieval of NO2 VCDs over China, called the

  19. Temporal variability in groundwater and surface water quality in humid agricultural catchments; Driving processes and consequences for regional water quality monitoring

    NARCIS (Netherlands)

    Rozemeijer, Joachim; Van Der Velde, Ype

    2014-01-01

    Considering the large temporal variability in surface water quality is essential for adequate water quality policy and management. Neglecting these dynamics may easily lead to decreased effectiveness of measures to improve water quality and to inefficient water quality monitoring. The objective of

  20. Temporal variability in groundwater and surface water quality in humid agricultural catchments; driving processes and consequences for regional water quality monitoring

    NARCIS (Netherlands)

    Rozemeijer, J.; Velde, van der Y.

    2014-01-01

    Considering the large temporal variability in surface water quality is essential for adequate water quality policy and management. Neglecting these dynamics may easily lead to decreased effectiveness of measures to improve water quality and to inefficient water quality monitoring. The objective of

  1. Apparatus and method of manufacture for depositing a composite anti-reflection layer on a silicon surface

    Science.gov (United States)

    Pain, Bedabrata (Inventor)

    2012-01-01

    An apparatus and associated method are provided. A first silicon layer having at least one of an associated passivation layer and barrier is included. Also included is a composite anti-reflection layer including a stack of layers each with a different thickness and refractive index. Such composite anti-reflection layer is disposed adjacent to the first silicon layer.

  2. Non-destructive quality evaluation of pepper (Capsicum annuum L.) seeds using LED-induced hyperspectral reflectance imaging

    Science.gov (United States)

    In this study, we develop a viability evaluation method for pepper (Capsicum annuum L.) seed based on hyperspectral reflectance imaging. The reflectance spectra of pepper seeds in the 400–700 nm range are collected from hyperspectral reflectance images obtained using blue, green, and red LED illumin...

  3. Determination of quality parameters of beers by the use of attenuated total reflectance-Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Llario, Rafael; Iñón, Fernando A; Garrigues, Salvador; de la Guardia, Miguel

    2006-04-15

    The estimation of important quality parameters of beers, such as original and real extracts and alcohol content, has been evaluated by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) using a partial least square (PLS) calibration approach. Two sample populations, one consisting of 24 samples and other of 21 samples, obtained from the Spanish market and covering different types of beer were used. The first set was used for building and validating the model, whereas the second, measured 6 months after, was used for evaluating its robustness. The spectral range and the size of the calibration set and its suitability for building the PLS model have been evaluated. Considering a calibration set comprised of 12 samples, selected via hierarchical cluster analysis, and a validation data set of 11 samples, the absolute mean difference (d(x-y)) and standard deviation of mean differences (s(x-y)) of the real extract, original extract and alcohol content were 0.009 and 0.069% (w/w), -0.021 and 0.20% (w/w) and -0.003 and 0.130% (v/v), respectively. The maximum error for the prediction of any of these three parameters for a new sample did not exceed 2.5%. These values were practically invariant for both tested data sets. The developed methodology favourably compares with the automatic reference methodology in terms of speed and reagent consumption and waste generation.

  4. A Comprehensive Review of the Evidence of the Impact of Surface Water Quality on Property Values

    Directory of Open Access Journals (Sweden)

    Sarah Nicholls

    2018-02-01

    Full Text Available The desirability of living on or close to water is reflected in sometimes substantial property price premiums. Water quality has an important influence on property prices, since it impacts a water body’s appearance, capacity to support wildlife, and recreational potential. As water quality continues to be altered by human use and activity, and in light of new threats posed by projected climate and associated environmental change, understanding the impact of changing quality on property prices, and the associated property tax base, is paramount. This paper reviews the body of evidence on this topic to date. Of the 43 distinct studies represented in the 48 publications reviewed, the expected, statistically significant relationship between water quality and property price was demonstrated in at least one of the models developed in all but two studies. As a whole, they provide convincing evidence that clean water has a positive effect on property values.

  5. Using integrated multivariate statistics to assess the hydrochemistry of surface water quality, Lake Taihu basin, China

    Directory of Open Access Journals (Sweden)

    Xiangyu Mu

    2014-09-01

    Full Text Available Natural factors and anthropogenic activities both contribute dissolved chemical loads to  lakes and streams.  Mineral solubility,  geomorphology of the drainage basin, source strengths and climate all contribute to concentrations and their variability. Urbanization and agriculture waste-water particularly lead to aquatic environmental degradation. Major contaminant sources and controls on water quality can be asssessed by analyzing the variability in proportions of major and minor solutes in water coupled to mutivariate statistical methods.   The demand for freshwater needed for increasing crop production puulation and industrialization occurs almost everywhere in in China and these conflicting needs have led to widespread water contamination. Because of heavy nutrient loadings from all of these sources, Lake Taihu (eastern China notably suffers periodic hyper-eutrophication and drinking water deterioration, which has led to shortages of freshwater for the City of Wuxi and other nearby cities. This lake, the third largest freshwater body in China, has historically beeen considered a cultural treasure of China, and has supported long-term fisheries. The is increasing pressure to remediate the present contamination which compromises both aquiculture and the prior economic base centered on tourism.  However, remediation cannot be effectively done without first characterizing the broad nature of the non-point source pollution. To this end, we investigated the hydrochemical setting of Lake Taihu to determine how different land use types influence the variability of surface water chemistry in different water sources to the lake. We found that waters broadly show wide variability ranging from  calcium-magnesium-bicarbonate hydrochemical facies type to mixed sodium-sulfate-chloride type. Principal components analysis produced three principal components that explained 78% of the variance in the water quality and reflect three major types of water

  6. Surface sediment quality relative to port activities: A contaminant-spectrum assessment.

    Science.gov (United States)

    Yu, Shen; Hong, Bing; Ma, Jun; Chen, Yongshan; Xi, Xiuping; Gao, Jingbo; Hu, Xiuqin; Xu, Xiangrong; Sun, Yuxin

    2017-10-15

    Ports are facing increasing environmental concerns with their importance to the global economy. Numerous studies indicated sediment quality deterioration in ports; however, the deterioration is not discriminated for each port activity. This study investigated a spectrum of contaminants (metals and organic pollutants) in surface sediments at 20 sampling points in Port Ningbo, China, one of the top five world ports by volume. The spectrum of contaminants (metals and organic pollutants) was quantified following marine sediment quality guidelines of China and USA and surface sediment quality was assessed according to thresholds of the two guidelines. Coupling a categorical matrix of port activities with the matrix of sedimentary contaminants revealed that contaminants were highly associated with the port operations. Ship repair posed a severe chemical risk to sediment. Operations of crude oil and coal loadings were two top activities related to organic pollutants in sediments while port operations of ore and container loadings discharged metals. Among the 20 sampling points, Cu, Zn, Pb, and DDT and its metabolites were the priority contaminants influencing sediment quality. Overall, surface sediments in Port Ningbo had relatively low environmental risks but ship repair is an environmental concern that must be addressed. This study provides a practical approach for port activity-related quality assessment of surface sediments in ports that could be applicable in many world sites. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Multi-pollutant surface objective analyses and mapping of air quality health index over North America.

    Science.gov (United States)

    Robichaud, Alain; Ménard, Richard; Zaïtseva, Yulia; Anselmo, David

    2016-01-01

    Air quality, like weather, can affect everyone, but responses differ depending on the sensitivity and health condition of a given individual. To help protect exposed populations, many countries have put in place real-time air quality nowcasting and forecasting capabilities. We present in this paper an optimal combination of air quality measurements and model outputs and show that it leads to significant improvements in the spatial representativeness of air quality. The product is referred to as multi-pollutant surface objective analyses (MPSOAs). Moreover, based on MPSOA, a geographical mapping of the Canadian Air Quality Health Index (AQHI) is also presented which provides users (policy makers, public, air quality forecasters, and epidemiologists) with a more accurate picture of the health risk anytime and anywhere in Canada and the USA. Since pollutants can also behave as passive atmospheric tracers, they provide information about transport and dispersion and, hence, reveal synoptic and regional meteorological phenomena. MPSOA could also be used to build air pollution climatology, compute local and national trends in air quality, and detect systematic biases in numerical air quality (AQ) models. Finally, initializing AQ models at regular time intervals with MPSOA can produce more accurate air quality forecasts. It is for these reasons that the Canadian Meteorological Centre (CMC) in collaboration with the Air Quality Research Division (AQRD) of Environment Canada has recently implemented MPSOA in their daily operations.

  8. Effect of Traditional Gold Mining to Surface Water Quality in Murung Raya District, Central Kalimantan Province

    OpenAIRE

    Wilopo, W; Resili, R; Putra, D P E

    2013-01-01

    There are many locations for traditional gold mining in Indonesia. One of these is in Murung Raya District, Central Kalimantan Province. Mining activities involving the application of traditional gold processing technology have a high potential to pollute the environment, especially surface water. Therefore, this study aims to determine the impact of gold mining and processing on surface water quality around the mine site. Based on the results of field surveys and laboratory analysis, our dat...

  9. Effect of non-uniform surface resistance on the quality factor of superconducting niobium cavity

    Science.gov (United States)

    Tan, Weiwei; Lu, Xiangyang; Yang, Ziqin; Zhao, Jifei; Yang, Deyu; Yang, Yujia

    2016-08-01

    The formula Rs = G /Q0 is commonly used in the calculation of the surface resistance of radio frequency niobium superconducting cavities. The applying of such equation is under the assumption that surface resistance is consistent over the cavity. However, the distribution of the magnetic field varies over the cavity. The magnetic field in the equator is much higher than that in the iris. According to Thermal Feedback Theory, it leads non-uniform distribution of the density of heat flux, which results in a different temperature distribution along the cavity inter surface. The BCS surface resistance, which depends largely on the temperature, is different in each local inner surface. In this paper, the effect of surface non-uniform resistance on the quality factor has been studied, through the calculation of Q0 in the original definition of it. The results show that it is necessary to consider the non-uniform distribution of magnetic field when the accelerating field is above 20 MV/m for TESLA cavities. Also, the effect of inhomogeneity of residual resistance on the quality factor is discussed. Its distribution barely affects the quality factor.

  10. Protocol for Validation of the Land Surface Reflectance Fundamental Climate Data Record using AERONET: Application to the Global MODIS and VIIRS Data Records

    Science.gov (United States)

    Roger, J. C.; Vermote, E.; Holben, B. N.

    2014-12-01

    The land surface reflectance is a fundamental climate data record at the basis of the derivation of other climate data records (Albedo, LAI/Fpar, Vegetation indices) and a key parameter in the understanding of the land-surface-climate processes. It is essential that a careful validation of its uncertainties is performed on a global and continuous basis. One approach is the direct comparison of this product with ground measurements but that approach presents several issues related to scale, the episodic nature of ground measurements and the global representativeness. An alternative is to compare the surface reflectance product to reference reflectance determined from Top of atmosphere reflectance corrected using accurate radiative transfer code and very detailed measurements of the atmosphere obtained over the AERONET sites (Vermote and al, 2014, RSE) which allows to test for a large range of aerosol characteristics; formers being important inputs for atmospheric corrections. However, the application of this method necessitates the definition of a very detailed protocol for the use of AERONET data especially as far as size distribution and absorption are concerned, so that alternative validation methods or protocols could be compared. This paper describes the protocol we have been working on based on our experience with the AERONET data and its application to the MODIS and VIIRS record.

  11. An Automatic System for Determining Solar Absorptance and Thermal Emittance of Surfaces from Spectral Normal Reflectance Measurements

    National Research Council Canada - National Science Library

    Teichman, Louis

    1965-01-01

    .... The system consists of two spectrophotometers used to make optical reflectance measurements, electronic digitizing equipment to record the data, and a high-speed electronic computer to calculate the desired results...

  12. Reflecting reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    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 challenge...... the current reflective paradigm I supervision and relate this to emotive, normative and formative views supervision. The paper is relevant for Nordic educational research into the supervision and guidance...

  13. Experimental study of surface quality and damage when drilling unidirectional CFRP composites

    Directory of Open Access Journals (Sweden)

    Eshetu D. Eneyew

    2014-10-01

    Full Text Available In this study, an experimental investigation on the drilling of unidirectional carbon fiber reinforced plastic (UD-CFRP composite was conducted using polycrystalline diamond (PCD tipped eight facet drill. The quality of the drilled hole surface was examined through surface roughness measurements and surface damage by scanning electron microscopy (SEM. It was found that fiber pullout occurred in two specific sectors relative to the angle between the cutting direction and the fiber orientation. The thrust force was highly influenced by the feed rate than the cutting speed and it shows a significant variation throughout the rotation of the drill.

  14. Technological capabilities of increasing surface quality of workpieces made of titanium alloy VT22 and stability of surface grinding

    Science.gov (United States)

    Soler, Ya I.; Salov, V. M.; Mai, D. S.

    2018-03-01

    Surface grinding of flat workpieces made of alloy VT22 was conducted by the periphery of a highly porous wheel (HPW) from cubic boron nitride CBN30 B107 100 OV K27 КF40 with three processing techniques (ij). They are 10 - cross-feed per stroke, HPW cutting into a workpiece changes alternately from up to down; 12 – cross-feed per double stroke during the up HPW cutting-in at the working stroke; 22 – cross-feed per double stroke during the down HPW cutting-in at the working stroke. With the involvement of artificial neural network models, it was revealed that to improve the quality of surfaces and stability of its formation, grinding should be conducted if ij = 12.

  15. Surface and ground water quality in a restored urban stream affected by road salts

    Science.gov (United States)

    In 2001 research began in Minebank Run, MD to examine the impact of restoration on water quality. Our research area was to determine if road salts in the surface and ground waters are detrimental to the stream channel restoration. The upstream reach (UP), above the Baltimore I-...

  16. A uniform, quality controlled Surface Ocean CO2 Atlas (SOCAT)

    Digital Repository Service at National Institute of Oceanography (India)

    Pfeil, B.; Olsen, A; Bakker, D.C.E.; Hankin, S.; Koyuk, H.; Kozyr, A; Malczyk, J.; Manke, A; Metzl, N.; Sabine, C.L.; Akl, J.; Alin, S.R.; Bates, N.; Bellerby, R.G.J.; Borges, A; Boutin, J.; Brown, P.J.; Cai, W.-J.; Chavez, F.P.; Chen, A; Cosca, C.; Fassbender, A.J.; Feely, R.A.; Gonzalez-Davila, M.; Goyet, C.; Hales, B.; Hardman-Mountford, N.; Heinze, C.; Hood, M.; Hoppema, M.; Hunt, C.W.; Hydes, D.; Ishii, M.; Johannessen, T.; Jones, S.D.; Key, R.M.; Kortzinger, A.; Landschutzer, P.; Lauvset, S.K.; Lefevre, N.; Lenton, A.; Lourantou, A.; Merlivat, L.; Midorikawa, T.; Mintrop, L.; Miyazaki, C.; Murata, A.; Nakadate, A.; Nakano, Y.; Nakaoka, S.; Nojiri, Y.; Omar, A.M.; Padin, X.A.; Park, G.-H.; Paterson, K.; Perez, F.F.; Pierrot, D.; Poisson, A.; Rios, A.F.; Santana-Casiano, J.M.; Salisbury, J.; Sarma, V.V.S.S.; et al

    by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO2, which had been subject to quality control (QC). Many additional CO2 data, not yet made...

  17. The variability of surface water quality indicators in relation to watercourse typology, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Langhammer, J.; Hartvich, Filip; Mattas, D.; Rödlová, S.; Zbořil, A.

    2012-01-01

    Roč. 184, č. 6 (2012), s. 3983-3999 ISSN 0167-6369 Institutional research plan: CEZ:AV0Z30460519 Keywords : water framework directive * typology * Surface water quality Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.592, year: 2012

  18. Control of surface quality of sub-millimeter cylindrical gold targets

    International Nuclear Information System (INIS)

    Zhang Yunwang; Du Kai; Wan Xiaobo; Xiao Jiang; Zheng Wei; Zhang Lin; Sun Jingyuan; Chen Jing

    2010-01-01

    The morphology, composition and causes of defects are analyzed to reduce defects on the gold layer prepared by electrochemical deposition from sulfite solution, and to improve the surface quality of sub-millimeter cylindrical gold targets, by means of SEM and EDS. The effects of current density, metallic impurity, organic pollution, pre-deposition parameters and mandrel quality on the quality of the gold plating are discussed, along with their mechanisms. The result indicates that the current density must be controlled strictly. The optimal current density ranges from 2.4 to 3.2 mA/cm 2 when the concentration of gold ranges from 13 to 22 g/L, and from 2.0 to 2.6 mA/ cm 2 when the concentration of gold ranges from 5 to 13 g/L. The parameters of predeposition must be optimized and the predeposition time should be no longer than 1 minute to improve the surface quality. In addition, organic pollution should be removed from the bath, and the mandrels should be of good quality without oxide on their surfaces. (authors)

  19. Effect of traditional gold mining to surface water quality in Murung Raya District, Central Kalimantan Province

    Directory of Open Access Journals (Sweden)

    W.Wilopo

    2013-10-01

    Full Text Available There are many locations for traditional gold mining in Indonesia. One of these is in Murung Raya District, Central Kalimantan Province. Mining activities involving the application of traditional gold processing technology have a high potential to pollute the environment, especially surface water. Therefore, this study aims to determine the impact of gold mining and processing on surface water quality around the mine site. Based on the results of field surveys and laboratory analysis, our data shows that the concentration of mercury (Hg and Cyanide (CN has reached 0.3 mg/L and 1.9 mg/L, respectively, in surface water. These values exceed the drinking water quality standards of Indonesia and WHO. Many people who live in the mining area use surface water for daily purposes including drinking, cooking, bathing and washing. This scenario is very dangerous because the effect of surface water contamination on human health cannot be immediately recognized or diagnosed. In our opinion the dissemination of knowledge regarding the treatment of gold mining wastewater is urgently required so that the quality of wastewater can be improved before it is discharged into the environment

  20. Adsorption of benzyldimethylhexadecylammonium chloride at the hydrophobic silica-water interface studied by total internal reflection Raman spectroscopy: effects of silica surface properties and metal salt addition.

    Science.gov (United States)

    Grenoble, Zlata; Baldelli, Steven

    2013-08-29

    The adsorption of the cationic surfactant benzyldimethylhexadecylammonium (BDMHA(+)) chloride was studied at an octadecyltrichlorosilane (OTS)-monolayer-modified silica-water interface by Raman spectroscopy in total internal reflection (TIR) geometry. The present study demonstrates the capabilities of this spectroscopic technique to evaluate thermodynamic and kinetic BDMHA(+)Cl(-) adsorption properties at the hydrophobic silica surface. The surface coverage of BDMHA(+) decreased by 50% at the hydrophobic OTS-silica surface relative to the surface coverage on bare silica; the dominating driving mechanisms for surfactant adsorption were identified as hydrophobic effects and head group charge screening by the electrolyte counterions. Addition of magnesium metal salt (MgCl2) to the aqueous solution (∼ neutral pH) lowered the surface coverage and moderately increased the Langmuir adsorption constants relative to those of the pure surfactant. These trends were previously observed at the hydrophilic, negatively charged silica surface but with a smaller change in the Gibbs free energy of adsorption at the hydrophobic silica surface. The hydrophobic OTS-silica surface properties resulted in shorter times for the surfactant to reach steady-state adsorption conditions compared to the slow adsorption kinetics previously seen with the surfactant at the hydrophilic surface. Adsorption isotherms, based on Raman signal intensities from spectral analysis, were developed according to the Langmuir adsorption model for the pure surfactant at the OTS-silica-water interface; the modified Langmuir model was applied to the surfactant adsorption in the presence of 5, 10, 50, and 100 mM magnesium chloride. Spectral analysis of the Raman scattering intensities and geometric considerations suggests a hemimicelle-type surface aggregate as the most likely surfactant structure at the OTS-silica surface. The different kinetics observed at the hydrophilic versus the hydrophobic silica surface

  1. UMTRA project technical assistance contractor quality assurance implementation plan for surface and ground water

    International Nuclear Information System (INIS)

    1994-09-01

    The Uranium Mill Tailings Remedial Action (UMTRA) Project Technical Assistance Contractor (TAC) Quality Assurance Implementation Plan (QAIP) outlines the primary requirements for integrating quality functions for TAC technical activities applied to the surface and ground water phases of the UMTRA Project. The QAIP is subordinate to the latest issue of the UMTRA Project TAC Quality Assurance Program Plan (QAPP). The QAIP addresses technical aspects of the TAC UMTRA Project surface and ground water programs. The QAIP is authorized and approved by the TAC Project Manager and QA manager. The QA program is designed to use monitoring, audit, and surveillance functions as management tools to ensure that all Project organization activities are carried out in a manner that will protect public health and safety, promote the success of the UMTRA Project and meet or exceed contract requirements

  2. High systemic and testicular thermolytic efficiency during heat tolerance test reflects better semen quality in rams of tropical breeds

    Science.gov (United States)

    Kahwage, Priscila Reis; Esteves, Sérgio Novita; Jacinto, Manuel Antônio Chagas; Junior, Waldomiro Barioni; Pezzopane, José Ricardo Macedo; de Andrade Pantoja, Messy Hannear; Bosi, Cristian; Miguel, Maria Carolina Villani; Mahlmeister, Kaue; Garcia, Alexandre Rossetto

    2017-10-01

    This study aimed to assess the capacity of Morada Nova (MN) and Santa Inês (SIN) rams to maintain body and testicular homeothermy under thermal challenge. For 5 days in the summer, 16 males (SIN = 7 and MN = 9) underwent a heat tolerance test, i.e., period 1—animals maintained in the shade (11 to 12 h); period 2—animals exposed to sunlight (12 to 13 h); and period 3—animals returned to the shade (13 to 14 h). The respiratory rate, heart rate, rectal temperature, and infrared surface temperatures (IRT) of the trunk, back, eyeball, and testicles were assessed in each period. The index of capacity of tolerance to insolation (ICTI), which indicates the animals' level of adaptability, was calculated for each animal. Semen quality and testicular parenchyma integrity were assessed before and after the thermal challenge. Statistical analyses were performed at 5% significance. In period 1, the variables had baseline values for both genotypes. In period 2, the variables involved in thermolysis significantly increased ( P animals were considered resilient to a thermal challenge. In addition, infrared thermography was an efficient tool to verify body and testicular thermoregulation.

  3. Visible and Near-IR Reflectance Spectra of Smectite Acquired Under Dry Conditions for Interpretation of Martian Surface Mineralogy

    Science.gov (United States)

    Morris, Richard V.; Achilles, Cherie N; Archer, Paul D.; Graff, Trevor G.; Agresti, David G.; Ming, Douglas W; Golden, Dadi C.; Mertzman, Stanley A.

    2011-01-01

    Visible and near-IR (VNIR) spectra from the MEx OMEGA and the MRO CRISM hyper-spectral imaging instruments have spectral features associated with the H2O molecule and M OH functional groups (M = Mg, Fe, Al, and Si). Mineralogical assignments of martian spectral features are made on the basis of laboratory VNIR spectra, which were often acquired under ambient (humid) conditions. Smectites like nontronite, saponite, and montmorillionite have interlayer H2O that is exchangeable with their environment, and we have acquired smectite reflectance spectra under dry environmental conditions for interpretation of martian surface mineralogy. We also obtained chemical, Moessbauer (MB), powder X-ray diffraction (XRD), and thermogravimetric (TG) data to understand variations in spectral properties. VNIR spectra were recorded in humid lab air at 25-35C, in a dynamic dry N2 atmosphere (50-150 ppmv H2O) after exposing the smectite samples (5 nontronites, 3 montmorillionites, and 1 saponite) to that atmosphere for up to approximately l000 hr each at 25-35C, approximately 105C, and approximately 215C, and after re-exposure to humid lab air. Heating at 105C and 215C for approximately 1000 hr is taken as a surrogate for geologic time scales at lower temperatures. Upon exposure to dry N2, the position and intensity of spectral features associated with M-OH were relatively insensitive to the dry environment, and the spectral features associated with H2O (e.g., approximately 1.90 micrometers) decreased in intensity and are sometimes not detectable by the end of the 215C heating step. The position and intensity of H2O spectral features recovered upon re-exposure to lab air. XRD data show interlayer collapse for the nontronites and Namontmorillionites, with the interlayer remaining collapsed for the latter after re-exposure to lab air. The interlayer did not collapse for the saponite and Ca-montmorillionite. TG data show that the concentration of H2O derived from structural OH was invariant

  4. Glazed ceramic roof tiles: influence of surface features in the solar reflectance index; Influencia das caracteristicas da superficie no indice de refletancia solar de telhas ceramicas esmaltadas

    Energy Technology Data Exchange (ETDEWEB)

    Bortoli, Leitcia Silva de; Stapait, Camila Cristina; Marinoski, Deivis Luis; Fredel, Marcio Celso; Schabbach, Luciana M., E-mail: luciana.maccarini@ufsc.br [Universidade Federal de Santa Catarina (UFSC), Blumenau, SC (Brazil)

    2016-07-01

    In this study the influence of surface features of ceramic roof tiles in the solar reflectance index were evaluated. Two glazed ceramic roof tiles (type stoneware) with the same color (ivory) but with different appearance (matte and brilliant) were the focus of the analysis. The Solar Reflectance Index (SRI) of the roofs tiles were determined by the solar reflectance values (UV-VIS-NIR) and emittance, measured in laboratory. The samples showed SRI> 39 in accordance with LEED certification criteria (Leadership in Energy and Environmental Design), contributing to minimizing the Heat Island Effects. Although the matte roof tile shows a slightly higher SRI value (82) than the brilliant one (78), the results for the variables that composes the SRI value (reflectance and emittance) were very similar. Analysis of XRD, SEM and EDS performed on the surfaces of the two roofs indicated for the matte glaze the presence of microcrystals (with barium and zinc) that can contribute to the slightly highest value of SRI. The roughness (optical interferometer white light) and the brightness (brightness meter) of the samples were also measured. (author)

  5. Final report for the project "Improving the understanding of surface-atmosphere radiative interactions by mapping surface reflectance over the ARM CART site" (award DE-FG02-02ER63351)

    Energy Technology Data Exchange (ETDEWEB)

    Alexander P. Trishchenko; Yi Luo; Konstantin V. Khlopenkov, William M. Park; Zhanqing Li; Maureen Cribb

    2008-11-28

    Surface spectral reflectance (albedo) is a fundamental variable affecting the transfer of solar radiation and the Earth’s climate. It determines the proportion of solar energy absorbed by the surface and reflected back to the atmosphere. The International Panel on Climate Change (IPCC) identified surface albedo among key factors influencing climate radiative forcing. Accurate knowledge of surface reflective properties is important for advancing weather forecasting and climate change impact studies. It is also important for determining radiative impact and acceptable levels of greenhouse gases in the atmosphere, which makes this work strongly linked to major scientific objectives of the Climate Change Research Division (CCRD) and Atmospheric Radiation Measurement (ARM) Program. Most significant accomplishments of eth project are listed below. I) Surface albedo/BRDF datasets from 1995 to the end of 2004 have been produced. They were made available to the ARM community and other interested users through the CCRS public ftp site ftp://ftp.ccrs.nrcan.gc.ca/ad/CCRS_ARM/ and ARM IOP data archive under “PI data Trishchenko”. II) Surface albedo properties over the ARM SGP area have been described for 10-year period. Comparison with ECMWF data product showed some deficiencies in the ECMWF surface scheme, such as missing some seasonal variability and no dependence on sky-conditions which biases surface energy budget and has some influence of the diurnal cycle of upward radiation and atmospheric absorption. III) Four surface albedo Intensive Observation Period (IOP) Field Campaigns have been conducted for every season (August, 2002, May 2003, February 2004 and October 2004). Data have been prepared, documented and transferred to ARM IOP archive. Nine peer-reviewed journal papers and 26 conference papers have been published.

  6. The effect of welding parameters on surface quality of AA6351 aluminium alloy

    International Nuclear Information System (INIS)

    Yacob, S; Ariffin, N; Ali, R; Arshad, A; Wahab, M I A; Ismail, S A; Roji, NS M; Din, W B W; Zakaria, M H; Abdullah, A; Yusof, M I; Kamarulzaman, K Z; Mahyuddin, A; Hamzah, M N; Roslan, R; MAli, M A; Ahsan, Q

    2015-01-01

    In the present work, the effects of gas metal arc welding-cold metal transfer (GMAW-CMT) parameters on surface roughness are experimentally assessed. The purpose of this study is to develop a better understanding of the effects of welding speed, material thickness and contact tip to work distance on the surface roughness. Experiments are conducted using single pass gas metal arc welding-cold metal transfer (GMAW-CMT) welding technique to join the material. The material used in this experiment was AA6351 aluminum alloy with the thickness of 5mm and 6mm. A Mahr Marsuft XR 20 machine was used to measure the average roughness (Ra) of AA6351 joints. The main and interaction effect analysis was carried out to identify process parameters that affect the surface roughness. The results show that all the input process parameters affect the surface roughness of AA6351 joints. Additionally, the average roughness (Ra) results also show a decreasing trend with increased of welding speed. It is proven that gas metal arc welding-cold metal transfer (GMAW-CMT)welding process has been successful in term of providing weld joint of good surface quality for AA6351 based on the low value surface roughness condition obtained in this setup. The outcome of this experimental shall be valuable for future fabrication process in order to obtained high good quality weld. (paper)

  7. Does quality control matter? Surface urban heat island intensity variations estimated by satellite-derived land surface temperature products

    Science.gov (United States)

    Lai, Jiameng; Zhan, Wenfeng; Huang, Fan; Quan, Jinling; Hu, Leiqiu; Gao, Lun; Ju, Weimin

    2018-05-01

    The temporally regular and spatially comprehensive monitoring of surface urban heat islands (SUHIs) have been extremely difficult, until the advent of satellite-based land surface temperature (LST) products. However, these LST products have relatively higher errors compared to in situ measurements. This has resulted in comparatively inaccurate estimations of SUHI indicators and, consequently, may have distorted interpretations of SUHIs. Although reports have shown that LST qualities are important for SUHI interpretations, systematic investigations of the response of SUHI indicators to LST qualities across cities with dissimilar bioclimates are rare. To address this issue, we chose eighty-six major cities across mainland China and analyzed SUHI intensity (SUHII) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) LST data. The LST-based SUHII differences due to inclusion or exclusion of MODIS quality control (QC) flags (i.e., ΔSUHII) were evaluated. Our major findings included, but are not limited to, the following four aspects: (1) SUHIIs can be significantly impacted by MODIS QC flags, and the associated QC-induced ΔSUHIIs generally accounted for 24.3% (29.9%) of the total SUHII value during the day (night); (2) the ΔSUHIIs differed between seasons, with considerable differences between transitional (spring and autumn) and extreme (summer and winter) seasons; (3) significant discrepancies also appeared among cities located in northern and southern regions, with northern cities often possessing higher annual mean ΔSUHIIs. The internal variations of ΔSUHIIs within individual cities also showed high heterogeneity, with ΔSUHII variations that generally exceeded 5.0 K (3.0 K) in northern (southern) cities; (4) ΔSUHIIs were negatively related to SUHIIs and cloud cover percentages (mostly in transitional seasons). No significant relationship was found in the extreme seasons. Our findings highlight the need to be extremely cautious when using LST

  8. Improving the SMAC atmospheric correction code by analysis of Meteosat Second Generation NDVI and surface reflectance data

    DEFF Research Database (Denmark)

    Proud, Simon Richard; Rasmussen, M.O.; Fensholt, R.

    2010-01-01

    . When examining the Normalised Difference Vegetation Index (NDVI), the relative difference between SMAC and in-situ values decreases by 1.5% with the improvements in place. Similarly, the mean relative difference between SMAC and 6S reflectance values decreases by a mean of 13, 14.5 and 8...

  9. Effects of electromagnetic field and lubricate condition on the surface quality of magnesium alloy billet during LFEC processing

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The microstructures of the magnesium billets could be improved markedly by low-frequency electro-magnetic casting (LFEC) processing. In fact, the low-frequency electromagnetic field (LFEF) also has favorite effect on the surface quality of billet. However, few public reports on the surface quality of LFEC magnesium billets could be found. Therefore, a new crystallizer with a metal internal sleeve to-gether with a kind of lubricant was designed aiming at lowing surface turning quantity, and the effects of casting velocity, electromagnetic condition and lubrication on the surface quality of magnesium billets were investigated. The results indicate that LFEF together with the lubricate condition would be responsible for the surface quality of the billets, and the high surface quality billets could be achieved by optimizing the casting conditions.

  10. Monitoring surface-water quality in Arizona: the fixed-station network

    Science.gov (United States)

    Tadayon, Saeid

    2000-01-01

    Arizona is an arid State in which economic development is influenced largely by the quantity and quality of water and the location of adequate water supplies. In 1995, surface water supplied about 58 percent of total withdrawals in Arizona. Of the total amount of surface water used in 1995, about 89 percent was for agriculture, 10 percent for public supply, and 1 percent for industrial supply (including mining and thermoelectric; Solley and others, 1998). As a result of rapid population growth in Arizona, historic agricultural lands in the Phoenix (Maricopa County) and Tucson (Pima County) areas are now being developed for residential and commercial use; thus, the amount of water used for public supply is increasing. The Clean Water Act was established by U.S. Congress (1972) in response to public concern about water-pollution control. The act defines a process by which the United States Congress and the citizens are informed of the Nation’s progress in restoring and maintaining the quality of our waters. The Arizona Department of Environmental Quality (ADEQ) is the State-designated agency for this process and, as a result, has developed a monitoring program to assess water quality in Arizona. The ADEQ is required to submit a water-quality assessment report to the United States Environmental Protection Agency (USEPA) every 2 years. The USEPA summarizes the reports from each State and submits a report to the Congress characterizing water quality in the United States. These reports serve to inform Congress and the public of the Nation’s progress toward the restoration and maintenance of water quality in the United States (Arizona Department of Environmental Quality, 1998).

  11. Remote Sensing of Black Lakes and Using 810 nm Reflectance Peak for Retrieving Water Quality Parameters of Optically Complex Waters

    Directory of Open Access Journals (Sweden)

    Tiit Kutser

    2016-06-01

    Full Text Available Many lakes in boreal and arctic regions have high concentrations of CDOM (coloured dissolved organic matter. Remote sensing of such lakes is complicated due to very low water leaving signals. There are extreme (black lakes where the water reflectance values are negligible in almost entire visible part of spectrum (400–700 nm due to the absorption by CDOM. In these lakes, the only water-leaving signal detectable by remote sensing sensors occurs as two peaks—near 710 nm and 810 nm. The first peak has been widely used in remote sensing of eutrophic waters for more than two decades. We show on the example of field radiometry data collected in Estonian and Swedish lakes that the height of the 810 nm peak can also be used in retrieving water constituents from remote sensing data. This is important especially in black lakes where the height of the 710 nm peak is still affected by CDOM. We have shown that the 810 nm peak can be used also in remote sensing of a wide variety of lakes. The 810 nm peak is caused by combined effect of slight decrease in absorption by water molecules and backscattering from particulate material in the water. Phytoplankton was the dominant particulate material in most of the studied lakes. Therefore, the height of the 810 peak was in good correlation with all proxies of phytoplankton biomass—chlorophyll-a (R2 = 0.77, total suspended matter (R2 = 0.70, and suspended particulate organic matter (R2 = 0.68. There was no correlation between the peak height and the suspended particulate inorganic matter. Satellite sensors with sufficient spatial and radiometric resolution for mapping lake water quality (Landsat 8 OLI and Sentinel-2 MSI were launched recently. In order to test whether these satellites can capture the 810 nm peak we simulated the spectral performance of these two satellites from field radiometry data. Actual satellite imagery from a black lake was also used to study whether these sensors can detect the peak

  12. Microbiological quality control of single-walled carbon-nanotubes-coated surfaces experimentally contaminated

    International Nuclear Information System (INIS)

    Natalizi, T.; Frioni, A.; Passeri, D.; Pantanella, F.

    2013-01-01

    The emergence of new nanotechnologies involves the spreading of nanoparticles in various fields of human life. Nanoparticles in general and, more specifically, carbon nanotubes have been adopted for many practical approaches i.e.: coatings for medical devices, food process industry and drug delivery. Humans will be increasingly exposed to nanoparticles but the susceptibility of nanostructured materials to microbial colonization in process of manufacturing and storage has not been thoroughly considered. Therefore, the microbiological quality control of nanoparticles plays a pivotal role. Different analytical methods have been attempted for detecting bacterial population contaminating a surface, but no one can be considered fully appropriate. Here, BioTimer Assay (BTA) and conventional sonication followed by colony forming units method (S-CFU) were applied for microbiological quality control of single-walled carbon nanotubes (SWCNTs)-coated surfaces experimentally contaminated with Streptococcus mutans and Pseudomonas aeruginosa. Our results demonstrated that S-CFU is unreliable to actually determine the number of bacteria, contaminating abiotic surfaces, as it does not detach all adherent bacteria and kills part of the bacterial population. Instead, BTA is a reliable method to enumerate bacteria colonizing SWCNTs-coated surfaces and can be considered a useful tool for microbiological quality control of nanomaterials for human use.

  13. Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

    Science.gov (United States)

    Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.; hide

    2014-01-01

    Meteorological and air-quality model simulations are analyzed alongside observations to investigate the role of the Chesapeake Bay breeze on surface air quality, pollutant transport, and boundary layer venting. A case study was conducted to understand why a particular day was the only one during an 11-day ship-based field campaign on which surface ozone was not elevated in concentration over the Chesapeake Bay relative to the closest upwind site and why high ozone concentrations were observed aloft by in situ aircraft observations. Results show that southerly winds during the overnight and early-morning hours prevented the advection of air pollutants from the Washington, D.C., and Baltimore, Maryland, metropolitan areas over the surface waters of the bay. A strong and prolonged bay breeze developed during the late morning and early afternoon along the western coastline of the bay. The strength and duration of the bay breeze allowed pollutants to converge, resulting in high concentrations locally near the bay-breeze front within the Baltimore metropolitan area, where they were then lofted to the top of the planetary boundary layer (PBL). Near the top of the PBL, these pollutants were horizontally advected to a region with lower PBL heights, resulting in pollution transport out of the boundary layer and into the free troposphere. This elevated layer of air pollution aloft was transported downwind into New England by early the following morning where it likely mixed down to the surface, affecting air quality as the boundary layer grew.

  14. DRINKING WATER QUALITY IN DISTRIBUTION SYSTEMS OF SURFACE AND GROUND WATERWORKS IN FINLAND

    Directory of Open Access Journals (Sweden)

    Jenni Meirami Ikonen

    2017-06-01

    Full Text Available Physico-chemical and microbiological water quality in the drinking water distribution systems (DWDSs of five waterworks in Finland with different raw water sources and treatment processes was explored. Water quality was monitored during four seasons with on-line equipment and bulk water samples were analysed in laboratory. Seasonal changes in the water quality were more evident in DWDSs of surface waterworks compared to the ground waterworks and artificially recharging ground waterworks (AGR. Between seasons, temperature changed significantly in every system but pH and EC changed only in one AGR system. Seasonal change was seen also in the absorbance values of all systems. The concentration of microbially available phosphorus (MAP, μg PO₄-P/l was the highest in drinking water originating from the waterworks supplying groundwater. Total assimilable organic carbon (AOC, μg AOC-C/l concentrations were significantly different between the DWDSs other than between the two AGR systems. This study reports differences in the water quality between surface and ground waterworks using a wide set of parameters commonly used for monitoring. The results confirm that every distribution system is unique, and the water quality is affected by environmental factors, raw water source, treatment methods and disinfection.

  15. Strategic Evaluation Tool for Surface Water Quality Management Remedies in Drinking Water Catchments

    Directory of Open Access Journals (Sweden)

    Huda Almaaofi

    2017-09-01

    Full Text Available Drinking water catchments (DWC are under pressure from point and nonpoint source pollution due to the growing human activities. This worldwide challenge is causing number of adverse effects, such as degradation in water quality, ecosystem health, and other economic and social pressures. Different evaluation tools have been developed to achieve sustainable and healthy drinking water catchments. However, a holistic and strategic framework is still required to adequately consider the uncertainty associated with feasible management remedies of surface water quality in drinking water catchments. A strategic framework was developed to adequately consider the uncertainty associated with management remedies for surface water quality in drinking water catchments. A Fuzzy Multiple Criteria Decision Analysis (FMCDA approach was embedded into a strategic decision support framework to evaluate and rank water quality remediation options within a typical fixed budget constraint faced by bulk water providers. The evaluation framework consists of four core aspects; namely, water quality, environmental, economic and social, and number of associated quantitative and qualitative criteria and sub-criteria. Final remediation strategy ranking was achieved through the application of the Euclidean Distance by the In-center of Centroids (EDIC.

  16. Surface water-quality assessment of the lower Kansas River basin, Kansas and Nebraska; project description

    Science.gov (United States)

    Stamer, J.K.; Jordan, P.R.; Engberg, R.A.; Dugan, J.T.

    1987-01-01

    In 1986 the U.S. Geological Survey began a National Water-Quality Assessment Program to: (1) provide nationally consistent descriptions of the current status of water quality for a large, diverse, and geographically distributed part of the Nation 's surface water resources; (2) where possible, define trends in water quality; and (3) identify and describe the relation between water quality and natural and land use factors. This report describes the pilot study of the lower Kansas River basin, which is one of four surface water pilot studies that will be used to test, and modify as necessary, assessment concepts and approaches in preparation for future full implementation of the national program. Water quality issues in the lower Kansas River basin are dominated by possible nonpoint sources of contamination from agricultural land, with issues including: (1) large sediment discharge in the streams and sediment deposition in the reservoirs caused by intensive cultivation of row crops and subsequent erosion; (2) occurrence of pesticides in streams and reservoirs that could impair the suitability of water for aquatic life and has the potential for impairing the water 's suitability for public supply; (3) bacterial contamination caused by runoff from pastureland and feedlot operations and municipal wastewater discharges; and (4) nutrient enrichment of reservoirs. Data from fixed stations will be used to determine frequency distributions of constituent concentrations and mass balances of constituents between stations. Subbasin or river reach studies will provide a better understanding of the origin, movement, and fate of potential contaminants. (Lantz-PTT)

  17. Light reflection models for computer graphics.

    Science.gov (United States)

    Greenberg, D P

    1989-04-14

    During the past 20 years, computer graphic techniques for simulating the reflection of light have progressed so that today images of photorealistic quality can be produced. Early algorithms considered direct lighting only, but global illumination phenomena with indirect lighting, surface interreflections, and shadows can now be modeled with ray tracing, radiosity, and Monte Carlo simulations. This article describes the historical development of computer graphic algorithms for light reflection and pictorially illustrates what will be commonly available in the near future.

  18. Improving the quality of cognitive behaviour therapy case conceptualization: the role of self-practice/self-reflection.

    Science.gov (United States)

    Haarhoff, Beverly; Gibson, Kerry; Flett, Ross

    2011-05-01

    CBT case conceptualization is considered to be a key competency. Prior to the publication in 2009 of Kuyken, Padesky and Dudley's book, little has been documented concerning methods for training conceptualization skills and the conceptualization process is usually perceived as predominantly an intellectual process. In this paper, the Declarative-Procedural-Reflective model of therapist skill acquisition provides a route to understanding how different kinds of knowledge systems can be integrated to enhance therapist skill acquisition. Sixteen recent graduates of a postgraduate diploma in cognitive behaviour therapy worked independently through a self-practice/self-reflection workbook designed to lead them through a series of CBT interventions commonly used to elicit the information required for a CBT conceptualization. The participants' self-reflections were thematically analyzed and uncovered the following inter-related themes: increased theoretical understanding of the CBT model, self-awareness, empathy, conceptualization of the therapeutic relationship, and adaptation of clinical interventions and practice. A tentative conclusion reached, based on the self-reflections of the participants, was that targeted self-practice/self-reflection enhanced case conceptualization skill by consolidating the Declarative, Procedural and Reflective systems important in therapist skill acquisition. © British Association for Behavioural and Cognitive Psychotherapies 2011

  19. Assessment of surface-water quantity and quality, Eagle River watershed, Colorado, 1947-2007

    Science.gov (United States)

    Williams, Cory A.; Moore, Jennifer L.; Richards, Rodney J.

    2011-01-01

    From the early mining days to the current tourism-based economy, the Eagle River watershed (ERW) in central Colorado has undergone a sequence of land-use changes that has affected the hydrology, habitat, and water quality of the area. In 2000, the USGS, in cooperation with the Colorado River Water Conservation District, Eagle County, Eagle River Water and Sanitation District, Upper Eagle Regional Water Authority, Colorado Department of Transportation, City of Aurora, Town of Eagle, Town of Gypsum, Town of Minturn, Town of Vail, Vail Resorts, City of Colorado Springs, Colorado Springs Utilities, and Denver Water, initiated a retrospective analysis of surface-water quantity and quality in the ERW.

  20. UMTRA project technical assistance contractor quality assurance implementation plan for surface and ground water, Revision 2

    International Nuclear Information System (INIS)

    1995-11-01

    This document contains the Technical Assistance Contractor (TAC) Quality Assurance Implementation Plan (QAIP) for the Uranium Mill Tailings Remedial Action (UMTRA) Project. The QAIP outlines the primary requirements for integrating quality functions for TAC technical activities applied to the surface and ground water phases of the UMTRA Project. The QA program is designed to use monitoring, audit, and surveillance activities as management tools to ensure that UMTRA Project activities are carried out in amanner to protect public health and safety, promote the success of the UMTRA Project, and meet or exceed contract requirements

  1. Disposable attenuated total reflection-infrared crystals from silicon wafer: a versatile approach to surface infrared spectroscopy.

    Science.gov (United States)

    Karabudak, Engin; Kas, Recep; Ogieglo, Wojciech; Rafieian, Damon; Schlautmann, Stefan; Lammertink, R G H; Gardeniers, Han J G E; Mul, Guido

    2013-01-02

    Attenuated total reflection-infrared (ATR-IR) spectroscopy is increasingly used to characterize solids and liquids as well as (catalytic) chemical conversion. Here we demonstrate that a piece of silicon wafer cut by a dicing machine or cleaved manually can be used as disposable internal reflection element (IRE) without the need for polishing and laborious edge preparation. Technical aspects, fundamental differences, and pros and cons of these novel disposable IREs and commercial IREs are discussed. The use of a crystal (the Si wafer) in a disposable manner enables simultaneous preparation and analysis of substrates and application of ATR spectroscopy in high temperature processes that may lead to irreversible interaction between the crystal and the substrate. As representative application examples, the disposable IREs were used to study high temperature thermal decomposition and chemical changes of polyvinyl alcohol (PVA) in a titania (TiO(2)) matrix and assemblies of 65-450 nm thick polystyrene (PS) films.

  2. Surface quality and topographic inspection of variable compliance part after precise turning

    Science.gov (United States)

    Nieslony, P.; Krolczyk, G. M.; Wojciechowski, S.; Chudy, R.; Zak, K.; Maruda, R. W.

    2018-03-01

    The paper presents the problem of precise turning of the mould parts with variable compliance and demonstrates a topographic inspection of the machined surface quality. The study was conducted for the cutting tools made of cemented carbide with coatings, in a range of variable cutting parameters. The long shaft with special axial hole, made of hardened 55NiCrMoV6 steel was selected as a workpiece. The carried out study included the stiffness measurement of the machining system, as well as the investigation of cutting force components. In this context, the surface topography parameters were evaluated using the stylus profile meter and analysed. The research revealed that the surface topography, alongside the 3D functional parameters, and PSD influences the performance of the machined surface. The lowest surface roughness parameters values, equalled to Sa = 1 μm and Sz = 4.3 μm have been obtained during turning with cutting speed vc = 90 m/min. The stable turning of variable compliance part affects the surface texture formation with a unidirectional perpendicular, anisotropic structure. Nevertheless, in case of unstable turning, the characteristic chatter marks are observed, and process dynamics has greater contribution in formation of surface finish than turning kinematics and elastic plastic deformation of workpiece.

  3. Status of and changes in water quality monitored for the Idaho statewide surface-water-quality network, 1989—2002

    Science.gov (United States)

    Hardy, Mark A.; Parliman, Deborah J.; O'Dell, Ivalou

    2005-01-01

    The Idaho statewide surface-water-quality monitoring network consists of 56 sites that have been monitored from 1989 through 2002 to provide data to document status and changes in the quality of Idaho streams. Sampling at 33 sites has covered a wide range of flows and seasons that describe water-quality variations representing both natural conditions and human influences. Targeting additional high- or low-flow sampling would better describe conditions at 20 sites during hydrologic extremes. At the three spring site types, sampling covered the range of flow conditions from 1989 through 2002 well. However, high flows at these sites since 1989 were lower than historical high flows as a result of declining ground-water levels in the Snake River Plain. Summertime stream temperatures at 45 sites commonly exceeded 19 and 22 degrees Celsius, the Idaho maximum daily mean and daily maximum criteria, respectively, for the protection of coldwater aquatic life. Criteria exceedances in stream basins with minimal development suggest that such high temperatures may occur naturally in many Idaho streams. Suspended-sediment concentrations were generally higher in southern Idaho than in central and northern Idaho, and network data suggest that the turbidity criteria are most likely to be exceeded at sites in southern Idaho and other sections of the Columbia Plateaus geomorphic province. This is probably because this province has more fine-grained soils that are subject to erosion and disturbance by land uses than the Northern Rocky Mountains province of northern and central

  4. Impacts of Solid Waste Leachate on Groundwater and Surface Water Quality

    International Nuclear Information System (INIS)

    Karim, S.

    2010-01-01

    The present investigation was carried out to assess the impacts of solid waste leachate on groundwater and surface water quality at unlined dumping site. Six leachate samples collected from different locations have average values of COD and BOD 2563 mg/L and 442 mg/L, respectively. Surface water samples were collected in two different seasons (rainy and non- rainy). Samples collected during non-rainy season were found to be more contaminated than rainy season. Soil samples collected from the depth of 1.5 m are contaminated with heavy metals (Cd, Cr, Fe and Zn) and E.coli. Presence of E.coli shows that leachate has deteriorated groundwater quality. (author)

  5. Effect of electroerosion grinding parameters on surface quality of cylindrical pieces out of tungsten monocrystals

    International Nuclear Information System (INIS)

    Zolotykh, B.N.; Marchuk, A.I.; Nikiforov, S.V.; Serdobov, B.F.; Yakunkin, M.M.

    1978-01-01

    Experimental data are presented on the examination of the electroerosion grinding of cylindrical parts made up of tungsten single crystals. Special attention has been paid to a comparative analysis of the influence of the electroerosion cutting out and grinding on the quality characteristics of a surface. The surface quality was assessed according to a widening of the X-ray emission line (110) by means of round diffraction patterns and by the metallographic method. It is shown that the microdistortions after the electroerosion grinding are considerably greater than those resulting from the electroerosion cutting out; however, after the electroerosion grinding the number of microcracks is considerably smaller. The experimental results obtained underwent a theoretical analysis within the framework of the Mitchell-Rockswell-Hirsch dislocation theory of failure of space-centered single crystals

  6. Descriptive Characteristics of Surface Water Quality in Hong Kong by a Self-Organising Map

    Directory of Open Access Journals (Sweden)

    Yan An

    2016-01-01

    Full Text Available In this study, principal component analysis (PCA and a self-organising map (SOM were used to analyse a complex dataset obtained from the river water monitoring stations in the Tolo Harbor and Channel Water Control Zone (Hong Kong, covering the period of 2009–2011. PCA was initially applied to identify the principal components (PCs among the nonlinear and complex surface water quality parameters. SOM followed PCA, and was implemented to analyze the complex relationships and behaviors of the parameters. The results reveal that PCA reduced the multidimensional parameters to four significant PCs which are combinations of the original ones. The positive and inverse relationships of the parameters were shown explicitly by pattern analysis in the component planes. It was found that PCA and SOM are efficient tools to capture and analyze the behavior of multivariable, complex, and nonlinear related surface water quality data.

  7. Descriptive Characteristics of Surface Water Quality in Hong Kong by a Self-Organising Map.

    Science.gov (United States)

    An, Yan; Zou, Zhihong; Li, Ranran

    2016-01-08

    In this study, principal component analysis (PCA) and a self-organising map (SOM) were used to analyse a complex dataset obtained from the river water monitoring stations in the Tolo Harbor and Channel Water Control Zone (Hong Kong), covering the period of 2009-2011. PCA was initially applied to identify the principal components (PCs) among the nonlinear and complex surface water quality parameters. SOM followed PCA, and was implemented to analyze the complex relationships and behaviors of the parameters. The results reveal that PCA reduced the multidimensional parameters to four significant PCs which are combinations of the original ones. The positive and inverse relationships of the parameters were shown explicitly by pattern analysis in the component planes. It was found that PCA and SOM are efficient tools to capture and analyze the behavior of multivariable, complex, and nonlinear related surface water quality data.

  8. NEW METHOD FOR ACTIVE SURFACES QUALITY INSPECTION FOR HIGH DIMENSIONS BEARINGS

    Directory of Open Access Journals (Sweden)

    BRAUN Barbu

    2016-07-01

    Full Text Available The paper presents a stage of an ample research on high quality control for different type of large dimension bearings, with application in wind turbines for electrical energy production. There is presented a new and efficient method for bearing’s active surfaces quality control, in terms of roughness, to ensure a good and safety functioning and a long life of these. The research involved the use of a powerful digital microscope for surface analysis followed by an assisted by PC algorithm for results obtaining in terms of roughness values. It has been observed that the proposed analyzing method could in the future to be successfully applied for a very large range of bearings, different dimensions and applications.

  9. Untreated runoff quality from roof and road surfaces in a low intensity rainfall climate.

    Science.gov (United States)

    Charters, Frances J; Cochrane, Thomas A; O'Sullivan, Aisling D

    2016-04-15

    Sediment and heavy metals in stormwater runoff are key pollutants of urban waterways, and their presence in stormwater is driven by climatic factors such as rainfall intensity. This study describes the total suspended solids (TSS) and heavy metal concentrations found in runoff from four different urban surfaces within a residential/institutional catchment, in a climate where rainfall is typically of low intensity (runoff quality from a compilation of international studies. The road runoff had the highest TSS concentrations, while copper and galvanized roof runoff had the highest copper and zinc concentrations, respectively. Pollutant concentrations were found to be significantly different between surfaces; quantification and prediction of pollutant contributions from urban surfaces should thus take account of the different surface materials, instead of being aggregated into more generalized categories such as land use. The TSS and heavy metal concentrations were found to be at the low to medium end of ranges observed internationally, except for total copper and zinc concentrations generated by dissolution of copper and galvanized roofing material respectively; these concentrations were at least as high as those reported internationally. TSS wash-off from the roofs was seen to be a source-limited process, where all available TSS is washed off during the rain event despite the low intensity rainfall, whereas both road TSS and heavy metals wash-off from roof and road surfaces appeared to all be transport-limited and therefore some carryover of pollutants occurs between rain events. A first flush effect was seen from most surfaces for TSS, but not for heavy metals. This study demonstrates that in low intensity rainfall climates, quantification of untreated runoff quality from key individual surface types in a catchment are needed to enable development of targeted and appropriately sized stormwater treatment systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Moth eye-inspired anti-reflective surfaces for improved IR optical systems & visible LEDs fabricated with colloidal lithography and etching.

    Science.gov (United States)

    Chan, Lesley W; Morse, Daniel E; Gordon, Michael J

    2018-05-08

    Near- and sub-wavelength photonic structures are used by numerous organisms (e.g. insects, cephalopods, fish, birds) to create vivid and often dynamically-tunable colors, as well as create, manipulate, or capture light for vision, communication, crypsis, photosynthesis, and defense. This review introduces the physics of moth eye (ME)-like, biomimetic nanostructures and discusses their application to reduce optical losses and improve efficiency of various optoelectronic devices, including photodetectors, photovoltaics, imagers, and light emitting diodes. Light-matter interactions at structured and heterogeneous surfaces over different length scales are discussed, as are the various methods used to create ME-inspired surfaces. Special interest is placed on a simple, scalable, and tunable method, namely colloidal lithography with plasma dry etching, to fabricate ME-inspired nanostructures in a vast suite of materials. Anti-reflective surfaces and coatings for IR devices and enhancing light extraction from visible light emitting diodes are highlighted.

  11. Study of the Effect of Material Machinability on Quality of Surface Created by Abrasive Water Jet

    Czech Academy of Sciences Publication Activity Database

    Klichová, Dagmar; Klich, Jiří

    2016-01-01

    Roč. 149, č. 149 (2016), s. 177-182 E-ISSN 1877-7058. [International Conference on Manufacturing Engineering and Materials, ICMEM 2016. Nový Smokovec, 06.06.2016-10.06.2016] R&D Projects: GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : machinability * surface roughness * abrasive water jet * study of quality * aluminium alloy * optical profilometer Subject RIV: JQ - Machines ; Tools http://www.sciencedirect.com/science/article/pii/S1877705816311614

  12. The impact of changing climate on surface and ground water quality in southeast of Ireland

    Science.gov (United States)

    Tribak, Kamal

    2015-04-01

    In the current changing climate globally, Ireland have been experiencing a yearly recurrent extreme heavy rainfall events in the last decade, with damaging visible effects socially, economically and on the environment. Ireland intensive agriculture production is a major treat to the aquatic environment, Nitrogen and phosphorus losses to the water courses are major causes to eutrophication. The European Water Frame Directive (WFD 2000/60/EC) and Nitrates Directive (91/676/EEC) sets a number of measures to better protect and improve water status. Five years of high temporal resolution river water quality data measurement from two contrasting catchment in the southeast of Ireland were correlated with rain fall and nutrients losses to the ground and surface water, additional to the integrated Southeast River District Basin ground and surface water quality to establish spatiotemporal connection to the agriculture activities, the first well-drained soil catchment had high coefficient correlation with rain fall with higher losses to groundwater, on the other hand higher nutrients losses to surface water were higher with less influence from groundwater recharge of N and P transfer, the poorly clay base soil contributed to higher increased losses to surface water during excessive rain fall. Agriculture activities, hydrology, geology and human interaction can interact according to their site specific setting and the effects will fluctuate dependent on the conditions influencing the impact on water quality, there is a requirement to better distinguish those effects together and identify areas and land uses control and nutrients management to improve the water quality, stakeholders co-operation along with effective polices, long term monitoring, nutrients pathways management and better understanding of the environmental factors interaction on national, regional and catchment scale to enable planning policies and enforcement measures to be more focused on areas of high risk

  13. The research into the quality of rock surfaces obtained by abrasive water jet cutting

    Czech Academy of Sciences Publication Activity Database

    Młynarczuk, M.; Skiba, M.; Sitek, Libor; Hlaváček, Petr; Kožušníková, Alena

    2014-01-01

    Roč. 59, č. 4 (2014), s. 925-940 ISSN 0860-7001 R&D Projects: GA MŠk ED2.1.00/03.0082; GA ČR GAP104/12/1988 Institutional support: RVO:68145535 Keywords : water jet * rock cutting * surface quality * roughness * variogram Subject RIV: JQ - Machines ; Tools Impact factor: 0.608, year: 2013 http://mining.archives.pl

  14. Improving the indoor air quality by using a surface emissions trap

    Science.gov (United States)

    Markowicz, Pawel; Larsson, Lennart

    2015-04-01

    The surface emissions trap, an adsorption cloth developed for reducing emissions of volatile organic compounds and particulate matter from surfaces while allowing evaporation of moisture, was used to improve the indoor air quality of a school building with elevated air concentrations of 2-ethyl-1-hexanol. An improvement of the perceived air quality was noticed a few days after the device had been attached on the PVC flooring. In parallel, decreased air concentrations of 2-ethyl-1-hexanol were found as well as a linear increase of the amounts of the same compound adsorbed on the installed cloth as observed up to 13 months after installation. Laboratory studies revealed that the performance of the device is not affected by differences in RH (35-85%), temperature (30-40 °C) or by accelerated aging simulating up to 10 years product lifetime, and, from a blinded exposure test, that the device efficiently blocks chemical odors. This study suggests that the device may represent a fast and efficient means of restoring the indoor air quality in a building e.g. after water damage leading to irritating and potentially harmful emissions from building material surfaces indoors.

  15. Reflections on Quality of Life as a College Concern to Facilitate Success of Students Who Are Deaf

    OpenAIRE

    DE Filippo, Carol Lee

    2004-01-01

    Quality of life is an area of nonacademic influence to which college programs can contribute significantly. It is proposed that a satisfying quality of life can enhance college success by increasing degree of academic engagement, regardless of a student's hearing status. A study of the quality of life of 200 deaf and hard-of-hearing students on a mainstream college campus is summarized as an example of how to define and measure baseline wellness using paper surveys and interviews. Life domain...

  16. Quality assurance of in-situ measurements of land surface albedo: A model-based approach

    Science.gov (United States)

    Adams, Jennifer; Gobron, Nadine; Widlowski, Jean-Luc; Mio, Corrado

    2016-04-01

    This paper presents the development of a model-based framework for assessing the quality of in-situ measurements of albedo used to validate land surface albedo products. Using a 3D Monte Carlo Ray Tracing (MCRT) radiative transfer model, a quality assurance framework is built based on simulated field measurements of albedo within complex 3D canopies and under various illumination scenarios. This method provides an unbiased approach in assessing the quality of field measurements, and is also able to trace the contributions of two main sources of uncertainty in field-measurements of albedo; those resulting from 1) the field measurement protocol, such as height or placement of field measurement within the canopy, and 2) intrinsic factors of the 3D canopy under specific illumination characteristics considered, such as the canopy structure and landscape heterogeneity, tree heights, ecosystem type and season.

  17. RAINWATER MANAGEMENT AIMING TO IMPROVE THE QUALITY OF URBAN SURFACE RUNOFF

    Directory of Open Access Journals (Sweden)

    I. HAIDU

    2015-10-01

    Full Text Available Rainwater Management Aiming to Improve the Quality of Urban Surface Runoff. Currently many urban areas experience the quality degradation of rooftop runoff and accumulated rainwater. The present study aims to estimate the volume of water draining from rooftops within an area of 0.68 km² in the municipality of Cluj-Napoca. The volume of water flowing from rooftops presents a beneficial alternative not only for collecting rainwater for later use, but also for reducing the volume of water and for improving surface runoff quality in urban areas. The procedure was based on the Michel Simplified SCS-CN model, a derived variant of the most popular hydrological model, the Soil Conservation Service Curve Number (SCS-CN. The results of the applied method reveal that the highest rooftop runoff water values correspond to the summer months, these being based on daily rainfall data. Estimating the volume of water draining from rooftops for future harvesting is an important step in the sustainable management of rainwater in urban areas and in improving water quality.

  18. Influences on the reflectance of Arctic sea ice and the impact of anthropogenic impurities on the surface shortwave radiation balance

    OpenAIRE

    Schulz, Hannes; Herber, Andreas; Birnbaum, Gerit; Seckmeyer, Gunther

    2014-01-01

    In order to investigate influences on the reflectance of snow covered Arctic sea ice, a discrete ordinate method and Mie-Theory based radiative transfer model has been set up. This model, the Snow on Sea Ice Model (SoSIM), is able to investigate changes in spectral and spectrally integrated (broadband) albedo of a multi-layer snow cover on sea ice due to varying snow microphysical parameters, atmospheric composition and incoming solar radiation. For typical conditions in the Arctic sea-ice ar...

  19. Quality Assessment of S-NPP VIIRS Land Surface Temperature Product

    Directory of Open Access Journals (Sweden)

    Yuling Liu

    2015-09-01

    Full Text Available The VIIRS Land Surface Temperature (LST Environmental Data Record (EDR has reached validated (V1 stage maturity in December 2014. This study compares VIIRS v1 LST with the ground in situ observations and with heritage LST product from MODIS Aqua and AATSR. Comparisons against U.S. SURFRAD ground observations indicate a similar accuracy among VIIRS, MODIS and AATSR LST, in which VIIRS LST presents an overall accuracy of −0.41 K and precision of 2.35 K. The result over arid regions in Africa suggests that VIIRS and MODIS underestimate the LST about 1.57 K and 2.97 K, respectively. The cross comparison indicates an overall close LST estimation between VIIRS and MODIS. In addition, a statistical method is used to quantify the VIIRS LST retrieval uncertainty taking into account the uncertainty from the surface type input. Some issues have been found as follows: (1 Cloud contamination, particularly the cloud detection error over a snow/ice surface, shows significant impacts on LST validation; (2 Performance of the VIIRS LST algorithm is strongly dependent on a correct classification of the surface type; (3 The VIIRS LST quality can be degraded when significant brightness temperature difference between the two split window channels is observed; (4 Surface type dependent algorithm exhibits deficiency in correcting the large emissivity variations within a surface type.

  20. Influence of the Lubricant Type on the Surface Quality of Steel Parts Obtained by Ironing

    Directory of Open Access Journals (Sweden)

    D. Adamović

    2015-06-01

    Full Text Available If it is needed to achieve a higher strain rate during the ironing process, which is possible without inter-stage annealing, the ironing is performed in succession through multiple dies. During that process, changes of friction conditions occur due to the change of contact conditions (dislodging of lubricants, changes of surface roughness, formation of friction junctions, etc.. In the multistage ironing, after each stage, the completely new conditions on the contact surfaces occur, which will significantly affect the quality of the workpiece surface. Lubricant has a very important role during the steel sheet metal ironing process; to separate the sheet metal surface from the tool and to reduce the friction between the contact surfaces. The influence of tribological conditions in ironing process is extremely important and it was a subject of study among researches in recent years, both in the real processes and on the tribo-models. Investigation of tribological conditions in the real processes is much longer and more expensive, so testing on the tribo-models is more frequent. Experimental research on the original tribo-model presented in this paper was aimed to indicate the changes that occur during multistage ironing, as well as to consider the impact of some factors (tool material, lubricant on die and punch on increase or decrease of the sheet metal surface roughness in ironing stages.