Sample records for surface reflectance properties

  1. 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


    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)

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

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.


    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...

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

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.


    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...... 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...

  4. Spectral reflectance of surface soils: Relationships with some soil properties (United States)

    Kiesewetter, C. H.


    Using a published atlas of reflectance curves and physicochemical properties of soils, a statistical analysis was carried out. Reflectance bands which correspond to five of the wavebands used by NASA's Thematic Mapper were examined for relationships to specific soil properties. The properties considered in this study include: Sand Content, Silt Content, Clay Content, Organic Matter Content, Cation Exchange Capacity, Iron Oxide Content and Moisture Content. Regression of these seven properties on the mean values of five TM bands produced results that indicate that the predictability of the properties can be increased by stratifying the data. The data was stratified by parent material, taxonomic order, temperature zone, moisture zone and climate (combined temperature and moisture). The best results were obtained when the sample was examined by climatic classes. The middle Infra-red bands, 5 and 7, as well as the visible bands, 2 and 3, are significant in the model. The near Infra-red band, band 4, is almost as useful and should be included in any studies. General linear modeling procedures examined relationships of the seven properties with certain wavebands in the stratified samples.

  5. Interactions of light with rough dielectric surfaces - Spectral reflectance and polarimetric properties (United States)

    Yon, S. A.; Pieters, C. M.


    The nature of the interactions of visible and NIR radiation with the surfaces of rock and mineral samples was investigated by measuring the reflectance and the polarization properties of scattered and reflected light for slab samples of obsidian and fine-grained basalt, prepared to controlled surface roughness. It is shown that the degree to which radiation can penetrate a surface and then scatter back out, an essential criterion for mineralogic determinations based on reflectance spectra, depends not only upon the composition of the material, but also on its physical condition such as sample grain size and surface roughness. Comparison of the experimentally measured reflectance and polarization from smooth and rough slab materials with the predicted models indicates that single Fresnel reflections are responsible for the largest part of the reflected intensity resulting from interactions with the surfaces of dielectric materials; multiple Fresnel reflections are much less important for such surfaces.

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

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Sørensen, K.


    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...

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

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


    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. The influence of surface reflectance anisotropy on estimation of soil properties (United States)

    Bartholomeus, Harm; Roosjen, Peter; Clevers, Jan


    The spatial variation in soil properties is an important factor for agricultural management. Unmanned airborne vehicles (UAV's) equipped with a hyperspectral mapping system may provide these data, but anisotropic reflectance effects may have an influence on the derived soil properties. Besides influencing the reflectance, angular observations may deliver added information about soil properties. We investigated the anisotropic behavior of 59 soil samples with a large variation in soil composition, by measuring their reflectance (350-2500 nm) over 92 different angles using a robot-based laboratory goniometer system. The results show that the anisotropic behavior of the soils influences the measured reflectance significantly, which limits the accurate prediction of soil properties (OM and clay especially). However, prediction accuracies of OM increase when spectra are measured under specific angles. Prediction accuracies further increase when a combination of observation angles is being used. Apart from that, using UAV's the wavelength range is limited to about 1000 nm. In general, this will decrease the model performance, but our results show that this effect can largely be compensated by combining multiple observation angles. Altogether, we demonstrate that surface anisotropy influences the prediction of soil properties negatively. This effect can be reduced by combining spectra acquired under different angles. Moreover, predictions can be improved if combinations of different observation angles are used.

  9. [The research of the relationship between snow properties and the bidirectional polarized reflectance from snow surface]. (United States)

    Sun, Zhong-Qiu; Wu, Zheng-Fang; Zhao, Yun-Sheng


    In the context of remote sensing, the reflectance of snow is a key factor for accurate inversion for snow properties, such as snow grain size, albedo, because of it is influenced by the change of snow properties. The polarized reflectance is a general phenomenon during the reflected progress in natural incident light In this paper, based on the correct measurements for the multiple-angle reflected property of snow field in visible and near infrared wavelength (from 350 to 2,500 nm), the influence of snow grain size and wet snow on the bidirectional polarized property of snow was measured and analyzed. Combining the results measured in the field and previous conclusions confirms that the relation between polarization and snow grain size is obvious in infrared wavelength (at about 1,500 nm), which means the degree of polarization increasing with an increase of snow grain size in the forward scattering direction, it is because the strong absorption of ice near 1,500 nm leads to the single scattering light contributes to the reflection information obtained by the sensor; in other word, the larger grain size, the more absorption accompanying the larger polarization in forward scattering direction; we can illustrate that the change from dry snow to wet snow also influences the polarization property of snow, because of the water on the surface of snow particle adheres the adjacent particles, that means the wet snow grain size is larger than the dry snow grain size. Therefore, combining the multiple-angle polarization with reflectance will provide solid method and theoretical basis for inversion of snow properties.

  10. 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.

  11. Coupled retrieval of aerosol properties and land surface reflection using the Airborne Multiangle SpectroPolarimetric Imager (United States)

    Xu, Feng; van Harten, Gerard; Diner, David J.; Kalashnikova, Olga V.; Seidel, Felix C.; Bruegge, Carol J.; Dubovik, Oleg


    The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) has been flying aboard the NASA ER-2 high-altitude aircraft since October 2010. In step-and-stare operation mode, AirMSPI acquires radiance and polarization data in bands centered at 355, 380, 445, 470*, 555, 660*, 865*, and 935 nm (* denotes polarimetric bands). The imaged area covers about 10 km by 11 km and is typically observed from nine viewing angles between ±66° off nadir. For a simultaneous retrieval of aerosol properties and surface reflection using AirMSPI, an efficient and flexible retrieval algorithm has been developed. It imposes multiple types of physical constraints on spectral and spatial variations of aerosol properties as well as spectral and temporal variations of surface reflection. Retrieval uncertainty is formulated by accounting for both instrumental errors and physical constraints. A hybrid Markov-chain/adding-doubling radiative transfer (RT) model is developed to combine the computational strengths of these two methods in modeling polarized RT in vertically inhomogeneous and homogeneous media, respectively. Our retrieval approach is tested using 27 AirMSPI data sets with low to moderately high aerosol loadings, acquired during four NASA field campaigns plus one AirMSPI preengineering test flight. The retrieval results including aerosol optical depth, single-scattering albedo, aerosol size and refractive index are compared with Aerosol Robotic Network reference data. We identify the best angular combinations for 2, 3, 5, and 7 angle observations from the retrieval quality assessment of various angular combinations. We also explore the benefits of polarimetric and multiangular measurements and target revisits in constraining aerosol property and surface reflection retrieval.

  12. Optical properties of nucleobase thin films as studied by attenuated total reflection and surface-enhanced Raman spectroscopy (United States)

    Kim, MinSuk; Ham, Won Kyu; Kim, Wonyoung; Hwangbo, Chang Kwon; Choi, Eun Ha; Lee, Geon Joon


    Optical properties of nucleobase thin films were studied by attenuated total reflection (ATR) and surface-enhanced Raman spectroscopy (SERS). Adenine and guanine films were deposited on fused silica and silver at room temperature by thermal evaporation, and the normal dispersion of refractive indices of transparent adenine and guanine films in the visible and near-infrared regions were analyzed. The measured ATR spectra of adenine (guanine) films and numerical simulations by optical transfer matrix formalism demonstrate that the shift of surface plasmon resonance (SPR) wavelength is approximately linearly proportional to the adenine (guanine) film thickness, indicating that SPR can be used for quantitative measurements of biomaterials. The Raman spectra indicated that the adenine (guanine) films can be deposited by thermal evaporation. The adenine (guanine) films on silver exhibited Raman intensity enhancement as compared to those on glass, which was attributed to the SPR effect of silver platform and might play a role as a hot plate for SERS detection of biomaterials.

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


    福富, 弘敦; 町田, 貴史; 横矢, 直和


    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...

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

    DEFF Research Database (Denmark)

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

    by their pitch distance and their angle in respect to the surface (Figure 2). The geometry was obtained by precision milling of a tool steel bar and replicated through silicone replica technology [2], and by hot embossing using Acrylonitrile Butadiene Styrene (ABS). A digital microscope has been used...

  15. Reflectance model for densely packed media: Estimates of the surface properties of the high-albedo satellites of Saturn (United States)

    Tishkovets, V. P.; Petrova, E. V.


    Interpretation of photometric and polarimetric observations of atmosphereless celestial bodies faces the problems connected with both the insufficient accuracy and level of details in groundbased observations and the current state of the theory of the multiple scattering of light. In application to sparse media, where the electromagnetic waves, propagating between the scatterers, can be considered as spherical (the socalled far-field approximation), this theory is rather well developed for both the diffuse and coherent components of the scattered radiation. In this paper, we show that this theory can be also successfully applied to the measurements of polarization of light scattered by densely packed, though nonabsorbing or weakly absorbing, media. For this purpose, we calculated the models for a semi-infinite layer of the medium composed of randomly oriented clusters of spherical particles and compared them with the data of laboratory and astronomical measurements. The potential of the present approach is illustrated by an example of the interpretation of the polarization measurements of the ice satellites of Saturn—Rhea and Enceladus—which allowed some properties of the surface of these celestial bodies to be estimated. In particular, the ratio of the surface area that makes no contribution to the negative polarization of light reflected at small phase angles to the area producing the negative polarization branch was found. Under the assumption of the same albedo of these areas, this ratio turned out to be 3.31-3.66 and 1.7-3.8 for Rhea and Enceladus, respectively. For Enceladus, it is difficult to obtain a sufficiently narrow range of the estimated parameters, since the number of measurement points in the phase dependence of polarization of this satellite is small. For the surface of Rhea, the estimated packing density of particles, participating in the opposition effects, is approximately 15%, while their smallest size is of the order of the wavelength of

  16. The outermost surface properties of silk fibroin films reflect ethanol-treatment conditions used in biomaterial preparation. (United States)

    Terada, Dohiko; Yokoyama, Yoshiyuki; Hattori, Shinya; Kobayashi, Hisatoshi; Tamada, Yasushi


    Silk fibroin has attracted interest as a biomaterial, given its many excellent properties. Cell attachment to silk substrates is usually weaker than to standard culture dishes, and cells cultured on silk films or hydrogels typically form spheroids and micro-aggregates. However, too little is known about the higher order structures and behavior of fibroin under different conditions to explain the features of silk fibroin as a culture substrate. For instance, different biomaterial surfaces, with distinct effects on cell culture, can be achieved by varying the conditions of crystallization by alcohol immersion. Here, we show that treatment of fibroin film with 90% ethanol has a harder surface than the <80% ethanol-treated fibroin, to which individual cells prefer to attach (and then expand on the surface), rather than to aggregate. We discuss the influence of alcohol concentration on the surface properties, based on surface analysis of the films. The surface analysis involved assessment of static and dynamic contact angles, zeta potential, changes in crystallinity and microscopic morphology of electrospun fibers, and texture changes of the outermost surface at a nanometer-scale captured by a scanning probe microscope. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Atlas of soil reflectance properties (United States)

    Stoner, E. R.; Baumgardner, M. F.; Biehl, L. L.; Robinson, B. F.


    A compendium of soil spectral reflectance curves together with soil test results and site information is presented in an abbreviated manner listing those soil properties most important in influencing soil reflectance. Results are presented for 251 soils from 39 states and Brazil. A narrative key describes relationships between soil parameters and reflectance curves. All soils are classified according to the U.S. soil taxonomy and soil series name for ease of identification.

  18. Joint Retrieval Of Surface Reflectance And Aerosol Properties: Application To MSG/SEVIRI in the framework of the aerosol_cci project (United States)

    Luffarelli, Marta; Govaerts, Yves; Goossens, Cedric


    A new versatile algorithm for the joint retrieval of surface reflectance and aerosol properties has been developed and tested at Rayference. This algorithm, named Combined Inversion of Surface and Aerosols (CISAR), includes a fast physically-based Radiative Transfer Model (RTM) accounting for the surface reflectance anisotropy and its coupling with aerosol scattering. This RTM explicitly solves the radiative transfer equation during the inversion process, without relying on pre-calculated integrals stored in LUT, allowing for a continuous variation of the state variables in the solution space. The inversion is based on a Optimal Estimation (OE) approach, which seeks for the best balance between the information coming from the observation and the a priori information. The a priori information is any additional knowledge on the observed system and it can concern the magnitude of the state variable or constraints on temporal and spectral variability. Both observations and priori information are provided with the corresponding uncertainty. For each processed spectral band, CISAR delivers the surface Bidirectional Reflectance Factor (BRF) and aerosol optical thickness, discriminating the effects of small and large particles. It also provides the associated uncertainty covariance matrix for every processed pixels. In the framework of the ESA aerosol_cci project, CISAR is applied on TOA BRF acquired by SEVIRI onboard Meteosat Second Generation (MSG) in the VIS0.6, VIS0.8 and NIR1.6 spectral bands. SEVIRI observations are accumulated during several days to document the surface anisotropy and minimize the impact of clouds. While surface radiative properties are supposed constant during this accumulation period, aerosol properties are derived on an hourly basis. The information content of each MSG/SEVIRI band will be provided based on the analysis of the posterior uncertainty covariance matrix. The analysis will demonstrate in particular the capability of CISAR to decouple

  19. Lunar surface reflectance by LALT aboard KAGUYA (United States)

    Noda, H.; Araki, H.; Ishihara, Y.; Tazawa, S.; Sasaki, S.; Kawano, N.


    The Laser Altimeter (LALT) aboard Japanese lunar explorer KAGUYA (SELENE) is a ranging instrument which measures the distance between the satellite and the lunar surface with accuracy of 1 m by detecting the timing delay of the reflected laser light. The main science goal of the LALT is to obtain the lunar global topographic data including polar regions for the study of the origin and the evolution of the Moon [1]. Besides, the LALT is equipped with an intensity monitor of the returned pulses. The intensity of the returned pulses contains information concerning surface roughness and reflectance of the footprints, which will contribute to the study of the lunar surface maturity and age. The reflectance at LALT wavelength (1064nm) is sensitive to the surface maturity and composition. The data should be particularly important at lunar polar regions where camera instruments should suffer from phase angle effects in the surface reflectance and moreover cannot obtain reflectance data at the permanently shadowed area. The normal operation of the LALT began on 30th, December 2007 after two months’ commissioning phase. Before the end of the normal operation phase in October 2008, the LALT measured more than 10 million range data. Unfortunately, due to the laser power decrease and also possible smaller surface reflectance than the expected value before launch (15 % at 1 micro meter), the return pulse intensity during the nominal mission phase is so small that they are not reliable enough to discuss the surface property. During the extended mission phase, which started November 2008, the satellite altitude decreased to 50 km. Due to the malfunction of the reaction wheel and high-voltage instruments were shutdown, the observation was suspended until 11th of February, 2009. LALT successfully resumed observation on 12th February and continued observation until the controlled crash of KAGUYA onto the Moon on 10th of June, 2009. Thanks to the lower orbit during this phase, the

  20. 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


    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

  1. Transmission and reflection properties of terahertz fractal metamaterials

    DEFF Research Database (Denmark)

    Malureanu, Radu; Lavrinenko, Andrei; Cooke, David


    We use THz time-domain spectroscopy to investigate transmission and reflection properties of metallic fractal metamaterial structures. We observe loss of free-space energy at certain resonance frequencies, indicating excitation of surface modes of the metamaterial.......We use THz time-domain spectroscopy to investigate transmission and reflection properties of metallic fractal metamaterial structures. We observe loss of free-space energy at certain resonance frequencies, indicating excitation of surface modes of the metamaterial....

  2. A climatology of visible surface reflectance spectra (United States)

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


    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.

  3. A Bayesian Reflection on Surfaces

    Directory of Open Access Journals (Sweden)

    David R. Wolf


    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.

  4. Reflection of Slow Electrons from Solid Surface (United States)

    Mustafaev, Alexander; Ainov, Matsak; Kaganovich, Igor; Demidov, Vladimir


    Given that progress of future plasma technologies depends on control of electron coefficient reflection r0, the development of methods of measurement and control of r0 is of great importance. Published experimental data on r0 for slow electrons are inconsistent and sometime give large values up to r0 ~ 0 , 8 and even higher. This talk presents a technique for r0 measurements in low pressure plasmas in the presence of transverse magnetic field. It is found that for poly-crystal surface, effective reflection coefficient can really reach value of 0.8. It is demonstrated that it is connected to additional reflection from potential barrier near the surfaces. The contribution of electron reflection from the barrier and the surface has been divided and studied. The data have been confirmed at different mono-crystal surfaces. This work was supported by DoE Fusion Energy Sciences contract DE-SC0001939 and Education Ministry of the RF.

  5. Specular Reflection from Rough Surfaces Revisited (United States)

    Yasuda, Kensei; Kim, Alvin; Cho, Hayley; Timofejev, Timofej; Walecki, Wojciech J.; Klep, James; Edelson, Amy S.; Walecki, Abigail S.; Walecki, Eve S.; Walecki, Peter S.


    In his beautiful paper, Hasan Fakhruddin reported observations of mirror-like reflections in the rough surface of a ground glass plate. Similar effects have been recently employed for metrology of the roughness of optical diffusers used in modern light emitting device illumination systems. We report the observations of specular reflection in…

  6. Simulation Tool for GNSS Ocean Surface Reflections


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


    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...

  7. On automatic visual inspection of reflective surfaces

    DEFF Research Database (Denmark)

    Kulmann, Lionel


    lighting methods in a framework, general usable for inspecting reflective surfaces. Special attention has been given to the design of illumination techniques to enhance defects of highly reflective aluminum sheets. The chosen optical system setup has been used to enhance surface defects of other reflective......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...

  8. Effect of Hydrological Properties on the Energy Shares of Reflected Waves at the Surface of a Partially Saturated Porous Solid

    Directory of Open Access Journals (Sweden)

    Mahabir Barak


    Full Text Available In the present study, the reflection of inhomogeneous waves is investigated at the stress-free plane surface based on multiphase poroelasticity theory. The porous medium is considered as dissipative due to the presence of viscosity in pores fluid. Four inhomogeneous (i.e. different direction of propagation and attenuation reflected waves (three longitudinal and one shear exists due to an incident wave. By using the appropriate boundary conditions, closed-form analytical expressions for the reflection coeffcients are derived at the stress-free surface. These reflection coeffcients are used to drive the analytical expressions for the energy shares of various reflected inhomogeneous waves. In mathematical framework, the conservation of incident energy is confirmed by considering an interaction energy between two dissimilar waves. It validates that the numerical calculations are analytically correct. Finally, a numerical example is considered to study the effects of viscous cross-coupling, porosity, saturation of gas, pore-characteristics and wave frequency on the energy shares of various reflected inhomogeneous waves and depicted graphically.

  9. Anisotropic reflectance characteristics of natural Earth surfaces. (United States)

    Brennan, B; Bandeen, W R


    The patterns of reflection of solar radiation from cloud, water, and land surfaces were measured with an aircraft-borne medium resolution radiometer. Reflectances in the 0.2-4.0-micro and 0.55-0.85-micro portions of the electromagnetic spectrum were investigated. Results indicate that the reflectance characteristics of most of the surface types measured are anisotropic. The anisotropy is dependent on the type of surface and the angles of incidence and reflection. In general, the anisotropy increases with increasing solar zenith angle. Clouds and forests show similar reflectance patterns, with forward and backward scattering peaks. Ocean surfaces yield a pattern similar to those of the clouds and forests but with an additional peak which is associated with sun glitter. Reflectances measured in the 0.2-4.0-micro band are generally lower than those in the 0.55-0.85-micro band under cloudy conditions. Anisotropy and spectral bandwidth should be accounted for when computing the albedo of the earth from narrow field-of-view measurements from satellites; otherwise, large errors may be expected to occur.

  10. Surface composition of Mercury from reflectance spectrophotometry (United States)

    Vilas, Faith


    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.

  11. Reflectance spectroscopy and asteroid surface mineralogy

    International Nuclear Information System (INIS)

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


    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

  12. Use of reflective surfaces on roadway embankment

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Doré, Guy


    Temperature measurements have been used to study the effect of two reflective surfaces on a roadway embankment in Forêt Montmorency, Québec, Canada. Both tested materials, Mapelastic (from MAPEI) and Colored Slurry (from Tech-Mix), have lead to a reduction in n-factor and proved to have very good...

  13. Conversion from surface wave to surface wave on reflection

    DEFF Research Database (Denmark)

    Novitsky, Andrey


    can be transmitted without changing its direction (nevertheless the amplitude varies). For other media parameters, only normally incident surface waves can be converted to surface waves. We propose applications of the predicted conversion as a beam splitter and polarization filter for surface waves.......We discuss the reflection and transmission of an incident surface wave to a pure surface wave state at another interface. This is allowed only for special media parameters: at least one of the media must be magnetic. We found such material characteristics that the obliquely incident surface wave...

  14. Simulation Tool for GNSS Ocean Surface Reflections

    DEFF Research Database (Denmark)

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


    . This impedance concept gives an accurate lower boundary condition in the determination of the electromagnetic field, and makes itpossible to simulate reflections and the effects of transitions between different mediums. A semi-isotropic Philipsspectrum is used to represent the air-sea interaction.Simulated GPS...... on the solution of the parabolic equation. The parabolic equation in our simulator is solvedusing the split-step sine transformation. The Earth’s surface is modeled with the use of an impedance model. The value of the Earth impedance is given as a function of the range along the surface of the Earth...

  15. ASTER L2 Surface Reflectance SWIR and ASTER L2 Surface Reflectance VNIR V003 (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...

  16. Reduction of Glass Surface Reflectance by Ion Beam Surface Modification

    Energy Technology Data Exchange (ETDEWEB)

    Mark Spitzer


    This is the final report for DOE contract DE-EE0000590. The purpose of this work was to determine the feasibility of the reduction of the reflection from the front of solar photovoltaic modules. Reflection accounts for a power loss of approximately 4%. A solar module having an area of one square meter with an energy conversion efficiency of 18% generates approximately 180 watts. If reflection loss can be eliminated, the power output can be increased to 187 watts. Since conventional thin-film anti-reflection coatings do not have sufficient environmental stability, we investigated the feasibility of ion beam modification of the glass surface to obtain reduction of reflectance. Our findings are generally applicable to all solar modules that use glass encapsulation, as well as commercial float glass used in windows and other applications. Ion implantation of argon, fluorine, and xenon into commercial low-iron soda lime float glass, standard float glass, and borosilicate glass was studied by implantation, annealing, and measurement of reflectance. The three ions all affected reflectance. The most significant change was obtained by argon implantation into both low-iron and standard soda-lime glass. In this way samples were formed with reflectance lower than can be obtained with a single-layer coatings of magnesium fluoride. Integrated reflectance was reduced from 4% to 1% in low-iron soda lime glass typical of the glass used in solar modules. The reduction of reflectance of borosilicate glass was not as large; however borosilicate glass is not typically used in flat plate solar modules. Unlike conventional semiconductor ion implantation doping, glass reflectance reduction was found to be tolerant to large variations in implant dose, meaning that the process does not require high dopant uniformity. Additionally, glass implantation does not require mass analysis. Simple, high current ion implantation equipment can be developed for this process; however, before the process

  17. Optical properties (bidirectional reflectance distribution function) of shot fabric

    NARCIS (Netherlands)

    Lu, Rong; Koenderink, Jan J.; Kappers, Astrid M L


    To study the optical properties of materials, one needs a complete set of the angular distribution functions of surface scattering from the materials. Here we present a convenient method for collecting a large set of bidirectional reflectance distribution function (BRDF) samples in the hemispherical

  18. The reflective surface of the MAGIC telescope (United States)

    Doro, M.; Bastieri, D.; Biland, A.; Dazzi, F.; Font, L.; Garczarczyk, M.; Ghigo, M.; Giro, E.; Goebel, F.; Kosyra, R.; Lorenz, E.; Mariotti, M.; Mirzoyan, R.; Peruzzo, L.; Pareschi, G.; Zapatero, J.


    The atmospheric Cherenkov telescope MAGIC for ground-based gamma-ray astronomy is operating since late 2003 on the Canary island of La Palma. Its 17 m diameter mirror is composed of 964 square all-aluminum mirrors of ˜0.5m side, making up a parabola of 236 m2 area. Each mirror is composed of a sandwich of two thin aluminum layers interspaced by a honeycomb structure that ensures rigidity, high temperature conductivity and low weight. The surface of each raw blank is diamond milled to provide high reflectivity and a slightly different focal length to fit the overall parabolic shape of the reflector. We report about the stability and performance of the surface exposed to the atmosphere for over 3 years. For the construction of the clone of the first telescope, dubbed MAGIC II, major improvements of the design and performance of the reflective surface were required. Given the good experience with aluminum mirrors, a similar assembly was tested, but the area was increased to 1 m2, which allowed to skip the inter-alignment of four mirrors within a panel and to reduce substantially the weight. The increased rigidity of the mirror unit resulted in an improved focussing quality. In addition, a second class of mirrors will be installed in the outermost part of the reflector, namely glass mirrors obtained by cold-slumping replica technique. Details on the construction of both type MAGIC II new mirrors and the 17 m reflector will be presented.

  19. Formation of Reflecting Surfaces Based on Spline Methods (United States)

    Zamyatin, A. V.; Zamyatina, E. A.


    The article deals with problem of reflecting barriers surfaces generation by spline methods. The cases of reflection when a geometric model is applied are considered. The surfaces of reflecting barriers are formed in such a way that they contain given points and the rays reflected at these points and hit at the defined points of specified surface. The reflecting barrier surface is formed by cubic splines. It enables a comparatively simple implementation of proposed algorithms in the form of software applications. The algorithms developed in the article can be applied in architecture and construction design for reflecting surface generation in optics and acoustics providing the geometrical model of reflex processes is used correctly.

  20. Asteroid surface materials: mineralogical characterizations from reflectance spectra

    International Nuclear Information System (INIS)

    Gaffey, M.J.; McCord, T.B.


    The interpretation of diagnostic parameters in the spectral reflectance data for asteroids provides a means of characterizing the mineralogy and petrology of asteroid surface materials. An interpretive technique based on a quantitative understanding of the functional relationship between the optical properties of a mineral assemblage and its mineralogy, petrology and chemistry can provide a considerably more sophisticated characterization of a single material than any matching or classification technique for those objects bright enough to allow spectral reflectance measurements. Albedos derived from radiometry and polarization data for individual asteroids can be used with spectral data to establish the spectral albedo, to define the optical density of the surface material and, in general to constrain mineralogical interpretations. (Auth.)

  1. Surface properties of beached plastics. (United States)

    Fotopoulou, Kalliopi N; Karapanagioti, Hrissi K


    Studying plastic characteristics in the marine environment is important to better understand interaction between plastics and the environment. In the present study, high-density polyethylene (HDPE), polyethylene terephalate (PET), and polyvinyl chloride (PVC) samples were collected from the coastal environment in order to study their surface properties. Surface properties such as surface functional groups, surface topography, point of zero charge, and color change are important factors that change during degradation. Eroded HDPE demonstrated an altered surface topography and color and new functional groups. Eroded PET surface was uneven, yellow, and occasionally, colonized by microbes. A decrease in Fourier transform infrared (FTIR) peaks was observed for eroded PET suggesting that degradation had occurred. For eroded PVC, its surface became more lamellar and a new FTIR peak was observed. These surface properties were obtained due to degradation and could be used to explain the interaction between plastics, microbes, and pollutants.

  2. Pegasus Airfield Repair and Protection: Laboratory Trials of White Ice Paint to Improve the Energy Reflectance Properties of the Glacial-Ice Runway Surface (United States)


    study is focused on the relative differ- ences in reflectivity for the varying painted ice and compacted snow treatments. Albedo studies have...could change both the albedo and strength charac- teristics of the white ice pavement once it re-freezes. On the positive side, there may be a...benefit to mixing the dry paint powder with the water and ice slurry during remediation of melt pools to help increase the albedo during and after

  3. Surface properties of HMX crystal (United States)

    Yee, R. Y.; Adicoff, A.; Dibble, E. J.


    The surface properties of Beta-HMX crystals were studied. The surface energies of three principal crystal faces were obtained by measuring contact angles with several reference liquids. The surface energies and polarity of the three crystal faces are found to be different.

  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.


    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. Structural properties of reflected Lévy processes

    DEFF Research Database (Denmark)

    Andersen, Lars Nørvang; Mandjes, Michel

    This paper considers a number of structural properties of reflected Lévy processes, where both one-sided reflection (at 0) and two-sided reflection (at both 0 and K > 0) are examined. With Vt being the position of the reflected process at time t, we focus on the analysis of ζ(t) := EVt and ξ(t) :...

  6. Infrared spectral reflectances of asteroid surfaces (United States)

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


    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.

  7. Mars analog minerals' spectral reflectance characteristics under Martian surface conditions (United States)

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


    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 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 with our laboratory data. These results will be useful in spectral libraries for characterizing Martian remote sensed data.

  8. Properties of interstellar dust in reflection nebulae

    International Nuclear Information System (INIS)

    Sellgren, K.


    Observations of interstellar dust in reflection nebulae are the closest analog in the interstellar medium to studies of cometary dust in our solar system. The presence of a bright star near the reflection nebula dust provides the opportunity to study both the reflection and emission characteristics of interstellar dust. At 0.1 to 1 micrometer, the reflection nebula emission is due to starlight scattered by dust. The albedo and scattering phase function of the dust is determined from observations of the scattered light. At 50 to 200 micrometers, thermal emission from the dust in equilibrium with the stellar radiation field is observed. The derived dust temperature determines the relative values of the absorption coefficient of the dust at wavelengths where the stellar energy is absorbed and at far infrared wavelengths where the absorbed energy is reradiated. These emission mechanisms directly relate to those seen in the near and mid infrared spectra of comets. In a reflection nebula the dust is observed at much larger distances from the star than in our solar system, so that the equilibrium dust temperature is 50 K rather than 300 K. Thus, in reflection nebulae, thermal emission from dust is emitted at 50 to 200 micrometer

  9. Viscoelasticity evaluation of rubber by surface reflection of supersonic wave. (United States)

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


    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.

  10. 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


    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

  11. Method and apparatus for aligning laser reflective surfaces

    International Nuclear Information System (INIS)

    Caruolo, A.B.; Davis, J.W.; Walch, A.P.


    Methods and apparatus used in the alignment of high power laser systems to obtain optimum performance are disclosed. An external source of visible radiation provides an alignment beam which is reflected along the axis of a resonator. Reflecting surfaces of the resonator are aligned with respect to the axis located by the visible beam

  12. Estimating surface reflectance from Himawari-8/AHI reflectance channels Using 6SV (United States)

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


    TOA (Top Of Atmospheric) reflectance observed by satellite is modified by the influence of atmosphere such as absorbing and scattering by molecular and gasses. Removing TOA reflectance attenuation which is caused by the atmospheric is essential. surface reflectance with compensated atmospheric effects used as important input data for land product such as Normalized Difference Vegetation Index (NDVI), Land Surface Albedo (LSA) and etc. In this study, we Second Simulation of a Satellite Signal in the Solar Spectrum Vector (6SV) Radiative Transfer Model (RTM) for atmospheric correction and estimating surface reflectance from Himawari-8/Advanced Himawari Imager (AHI) reflectance channels. 6SV has the advantage that it has high accuracy by performing the atmospheric correction by dividing the width of the satellite channel by 2.5 nm, but it is slow to use in the operation. So, we use LUT approach to reduce the computation time and avoid the intensive calculation required for retrieving surface reflectance. Estimated surface reflectance data were compared with PROBA-V S1 data to evaluate the accuracy. As a result Root Mean Square Error (RMSE) and bias were about 0.05 and -0.02. It is considered that this error is due to the difference of angle component and Spectral Response Function (SRF) of each channel.

  13. 100% reflectivity from a monolithic dielectric microstructured surface


    Brückner, F.; Clausnitzer, T.; Burmeister, O.; Friedrich, D.; Kley, E.; Danzmann, K.; Tünnermann, A.; Schnabel, R.


    Here, we propose a new mirror architecture which is solely based upon a monolithic dielectric micro-structured surface. Hence, the mirror device, which consists of a possibly mono-crystalline bulk material, can in principle simultaneously provide perfect reflectivity and lowest mechanical loss. By specifically structuring the monolithic surface, resulting in T-shaped ridges of a subwavelength grating, a resonant behavior of light coupling can be realized, leading to theoretically 100% reflect...

  14. Diffuse reflection of ultracold neutrons from low-roughness surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Atchison, F.; Daum, M.; Henneck, R.; Horisberger, M.; Kirch, K.; Lauss, B.; Mtchedlishvili, A.; Meier, M.; Petzoldt, G.; Schelldorfer, R.; Zsigmond, G. [Paul Scherrer Institut, PSI, Villigen (Switzerland); Heule, S.; Knecht, A. [Paul Scherrer Institut, PSI, Villigen (Switzerland); University Zuerich, Zuerich (Switzerland); Kasprzak, M. [Paul Scherrer Institut, PSI, Villigen (Switzerland); Stefan Meyer Institut, Vienna (Austria); Kuzniak, M. [Paul Scherrer Institut, PSI, Villigen (Switzerland); Jagiellonian University, Smoluchowski Institute of Physics, Cracow (Poland); Plonka-Spehr, C. [Institut Laue Langevin, ILL, Grenoble (France); Straumann, U. [University Zuerich, Zuerich (Switzerland)


    We report a measurement of the reflection of ultracold neutrons from flat, large-area plates of different Fermi potential materials with low surface roughness. The results were used to test two diffuse reflection models, the well-known Lambert model and the micro-roughness model which is based on wave scattering. The Lambert model fails to reproduce the diffuse reflection data. The surface roughness b and correlation length w, obtained by fitting the micro-roughness model to the data are in the range 1{<=}b{<=}3 nm and 10{<=}w{<=}120 nm, in qualitative agreement with independent measurements using atomic force microscopy. (orig.)

  15. Diffuse reflection of ultracold neutrons from low-roughness surfaces

    International Nuclear Information System (INIS)

    Atchison, F.; Daum, M.; Henneck, R.; Horisberger, M.; Kirch, K.; Lauss, B.; Mtchedlishvili, A.; Meier, M.; Petzoldt, G.; Schelldorfer, R.; Zsigmond, G.; Heule, S.; Knecht, A.; Kasprzak, M.; Kuzniak, M.; Plonka-Spehr, C.; Straumann, U.


    We report a measurement of the reflection of ultracold neutrons from flat, large-area plates of different Fermi potential materials with low surface roughness. The results were used to test two diffuse reflection models, the well-known Lambert model and the micro-roughness model which is based on wave scattering. The Lambert model fails to reproduce the diffuse reflection data. The surface roughness b and correlation length w, obtained by fitting the micro-roughness model to the data are in the range 1≤b≤3 nm and 10≤w≤120 nm, in qualitative agreement with independent measurements using atomic force microscopy. (orig.)

  16. On the reflection point where light reflects to a known destination on quadratic surfaces. (United States)

    Gonçalves, Nuno


    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.

  17. A light reflecting apparatus including a multi-aberration light reflecting surface (United States)

    Sawicki, R.H.; Sweatt, W.


    A light reflecting apparatus including a multi-aberration bendable light reflecting surface is disclosed herein. This apparatus includes a structural assembly comprised of a rectangular plate which is resiliently bendable, to a limited extent, and which has a front side defining the multi-aberration light reflecting surface and an opposite back side, and a plurality of straight leg members rigidly connected with the back side of the plate and extending rearwardly therefrom. The apparatus also includes a number of different adjustment mechanisms, each of which is connected with specific ones of the leg members. These mechanisms are adjustably movable in different ways for applying corresponding forces to the leg members in order to bend the rectangular plate and light reflecting surface into different predetermined curvatures and which specifically include quadratic and cubic curvatures corresponding to different optical aberrations.

  18. The effect of radiation-thermal treatment on the physicochemical properties of the Ni-Mo/Al2O3 hydrotreatment catalyst. II. UV-Vis diffuse reflectance spectra of surface compounds after irradiation

    International Nuclear Information System (INIS)

    Solovetskii, Yu.I.; Miroshinichenko, I.I.; Lunin, V.V.


    Radiation-thermal damage of the surface and the active metal phases of hydrodesulfurization Ni-Mo/Al 2 O 3 catalysts by a fast electron beam of up to 2.0 MeV energy was studied. UV-Vis diffuse reflectance spectra of the industrial and model coked systems after radiation-thermal treatment were measured. 14 refs., 2 figs

  19. Vesta surface thermal properties map (United States)

    Capria, Maria Teresa; Tosi, F.; De Santis, Maria Cristina; Capaccioni, F.; Ammannito, E.; Frigeri, A.; Zambon, F; Fonte, S.; Palomba, E.; Turrini, D.; Titus, T.N.; Schroder, S.E.; Toplis, M.J.; Liu, J.Y.; Combe, J.-P.; Raymond, C.A.; Russell, C.T.


    The first ever regional thermal properties map of Vesta has been derived from the temperatures retrieved by infrared data by the mission Dawn. The low average value of thermal inertia, 30 ± 10 J m−2 s−0.5 K−1, indicates a surface covered by a fine regolith. A range of thermal inertia values suggesting terrains with different physical properties has been determined. The lower thermal inertia of the regions north of the equator suggests that they are covered by an older, more processed surface. A few specific areas have higher than average thermal inertia values, indicative of a more compact material. The highest thermal inertia value has been determined on the Marcia crater, known for its pitted terrain and the presence of hydroxyl in the ejecta. Our results suggest that this type of terrain can be the result of soil compaction following the degassing of a local subsurface reservoir of volatiles.

  20. Reflection characteristics of a composite planar AMC surface

    Directory of Open Access Journals (Sweden)

    Ruey-Bing Hwang


    Full Text Available This study investigates the reflection characteristics of a composite Artificial Magnetic Conductor (AMC surface consisting of multiple orthogonal gradient AMC surfaces arranged in a two-dimensional periodic pattern. The gradient AMC surface in this study consists of square metal patches of variable size printed on a grounded dielectric substrate. Due to the orthogonal placement of the gradient AMC surface, the incident energy of a plane wave normally incident on the composite AMC surface will be reflected into four major lobes away from the impinging direction. To achieve a systematical design, a simple formula based on array antenna theory was developed to determine the reflection pattern of the gradient AMC surface illuminated by a normal incident plane wave. A time-domain full-wave simulation was also carried out to calculate the electromagnetic fields in the structure and the far-field patterns. The scattering patterns of the structure were measured in an electromagnetic anechoic chamber. Results confirm the design principle and procedures in this research. Since such a composite AMC surface can be easily fabricated using the standard printed circuit board technique without via-hole process, it may have potential applications in beam-steering and radar cross section reduction.

  1. Relationship between microstructure of the skin surface and surface reflection based on geometric optics. (United States)

    Yoshida, Kenichiro; Miyaki, Masahiro; Ojima, Nobutoshi; Iwata, Kayoko


    The behavior of reflected light in skin affects skin appearance and provides clues as to the internal condition of the skin. Surface topography is one of the central physical factors contributing to surface reflection. We tried to clarify the relationship between microstructure of the skin surface and surface reflection based on geometric optics. Microstructures and surface reflections in the left cheeks of adult females were evaluated. Skin topography was acquired measuring replicas using confocal laser microscopy. Surface topography was used to calculate arithmetical mean deviation of the surface (S(a)), and geometric index from gradient of the surface (S(grad)), which is expected to correlate with the directionality of surface reflection (DoSR) based on geometric optics. A surface reflection image was acquired from differently polarized pictures of a face, and the index of surface reflection (I(obs)) was calculated as the average pixel value of the area of shine. Correlations between indices were then evaluated. S(grad) and S(a) showed significant correlation (preflection from the reflection model than S(a). In addition, S(grad) can explain differences in DoSR for some panelists even in the case of an identical S(a). The topographic element involved in DoSR was extracted from height mapping. S(grad) reflects the ratio of flat area, offering a more effective indicator than S(a) for distinguishing topographic characteristics with respect to surface reflection. Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  2. Quality Assessment of Landsat Surface Reflectance Products Using MODIS Data (United States)

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


    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

  3. Quality-factor and reflection-coefficient estimation using reflected surface waves

    NARCIS (Netherlands)

    Draganov, D.S.; Ruigrok, E.N.; Ghose, R.; Mikesell, D.; Van Wijk, K.


    We propose a method for estimating the reflection coefficient of a subvertical boundary and the the quality factor of the medium between a receiver and the subvertical boundary. The method uses surface waves from transient deterministic sources and is inspired by the occurrence of non-physical

  4. Copper-assisted, anti-reflection etching of silicon surfaces (United States)

    Toor, Fatima; Branz, Howard


    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.

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


    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.

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

    International Nuclear Information System (INIS)

    Barchesi, D.; Otto, A.


    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.

  7. Development of paints with infrared radiation reflective properties

    Directory of Open Access Journals (Sweden)

    Eliane Coser


    Full Text Available AbstractLarge buildings situated in hot regions of the Globe need to be agreeable to their residents. Air conditioning is extensively used to make these buildings comfortable, with consequent energy consumption. Absorption of solar visible and infrared radiations are responsible for heating objects on the surface of the Earth, including houses and buildings. To avoid excessive energy consumption, it is possible to use coatings formulated with special pigments that are able to reflect the radiation in the near- infrared, NIR, spectrum. To evaluate this phenomenon an experimental study about the reflectivity of paints containing infrared-reflective pigments has been made. By irradiating with an IR source and by measuring the surface temperatures of the samples we evaluated: color according to ASTM D 2244-14, UV/VIS/NIR reflectance according to ASTM E 903-12 and thermal performance. Additionally, the spectral reflectance and the IR emittance were measured and the solar reflectance of the samples were calculated. The results showed that plates coated with paints containing IR-reflecting pigments displayed lower air temperature on the opposite side as compared to conventional coatings, indicating that they can be effective to reflect NIR and decrease the temperature of buildings when used in roofs and walls.

  8. Reflectance variability of surface coatings reveals characteristic eigenvalue spectra (United States)

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


    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. Application of anti-reflection structures on curved surfaces (United States)

    Yamamoto, Kazuya; Yamamoto, Takeshi; Takaoka, Toshimitsu; Seigo, Masafumi; Kitagawa, Seiichiro


    Conventional lens manufacturing is accomplished by injection molding followed by application of a thin film anti-reflection coating. This requires several production steps, each with the associated constraints. Here we report a technique for production of injection molded lenses with conical sub-wavelength grating anti-reflection structures. While similar structures have been made in the past, our technique allows the sub-wavelength structure to be created on curved surfaces during the injection molding process, reducing the number of steps in the manufacturing process. The advantage of this new technology is that anti-reflection function is created without any additional process(es) conventionally required but by a single injection molding process to make lens normally, through which substantial cost saving will be achieved.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  11. RTM-based Teleseismic Reflection Tomography with Free Surface Multiples (United States)

    Burdick, S. A.; De Hoop, M. V.; van der Hilst, R. D.


    Receiver function analysis of teleseismic converted and free surface reflected phases has long been a cornerstone of lithospheric studies. Discontinuities in elastic properties are revealed by deconvolving the incident wavefield from scattered phases and projecting the time differences to depth to form an image. The accuracy of the image is determined to a large extent by the accuracy of the method and background velocity model used, but popular approaches for projecting receiver functions to depth commonly rely on simplifying assumptions of a 1D velocity and planar discontinuities. In tectonically complex regions like subduction zones and rift systems, strong heterogeneity can create an ambiguous tradeoff between the background velocity and the depth of the discontinuities. Furthermore, such structures are apt to create caustics at high frequencies, rendering ray-based methods inadequate. In order to better constrain the background velocity and correctly place the discontinuities at depth, we employ a novel reverse-time migration (RTM) based reflection tomography method. We adapt our reflection tomography from exploration seismology for use with teleseismic phases. Active source methods for exploration have focused on the annihilation of extended images - image gathers formed with different subsurface angle or offset information - as a means of judging the accuracy of the model. Applying these approaches to teleseismic data is untenable because 1) the sparse and uneven distribution of earthquake sources leads to the incomplete construction of extended image, 2) the imperfect separation and source deconvolution of the scattered wavefield render previous error measurements unreliable, and 3) the planar geometry of incoming arrivals makes measures of subsurface offset insensitive to perturbations in the model. To overcome these obstacles, we have developed a flexible approach based on pairwise single-source image correlations. We determine the success of the RTM and

  12. Low cloud investigations for project FIRE: Island studies of cloud properties, surface radiation, and boundary layer dynamics. A simulation of the reflectivity over a stratocumulus cloud deck by the Monte Carlo method. M.S. Thesis Final Report (United States)

    Ackerman, Thomas P.; Lin, Ruei-Fong


    The radiation field over a broken stratocumulus cloud deck is simulated by the Monte Carlo method. We conducted four experiments to investigate the main factor for the observed shortwave reflectively over the FIRE flight 2 leg 5, in which reflectivity decreases almost linearly from the cloud center to cloud edge while the cloud top height and the brightness temperature remain almost constant through out the clouds. From our results, the geometry effect, however, did not contribute significantly to what has been observed. We found that the variation of the volume extinction coefficient as a function of its relative position in the cloud affects the reflectivity efficiently. Additional check of the brightness temperature of each experiment also confirms this conclusion. The cloud microphysical data showed some interesting features. We found that the cloud droplet spectrum is nearly log-normal distributed when the clouds were solid. However, whether the shift of cloud droplet spectrum toward the larger end is not certain. The decrease of number density from cloud center to cloud edges seems to have more significant effects on the optical properties.

  13. Reliable determination of tissue optical properties from spatially resolved reflectance (United States)

    Gladytz, Thomas; Hoppe, Alexander; Cantow, Kathleen; Pohlmann, Andreas; Flemming, Bert; Niendorf, Thoralf; Seeliger, Erdmann; Grosenick, Dirk


    Spatially resolved reflectance is a frequently used technique to derive optical properties and physiological parameters of tissue. We have evaluated the accuracy of this method by investigations on a set of phantoms with known optical properties derived from time-resolved measurements. The recorded profiles of spatially resolved reflectance were analyzed by a Monte Carlo model of photon transport. When we took only the shape of the measured profiles into account, we got only poor estimates of the optical properties. In particular, the absorption was strongly underestimated. The main reason for failing of this approach is that the shape of the measured profiles can be well described by many combinations of absorption and reduced scattering coefficients. The separation between scattering and absorption was strongly improved when the reflectance data were calibrated by using a reference phantom. We applied both the relative and the calibration based analysis method to reflectance data obtained from in vivo investigations on the kidney of rats. Despite the limited number of only 4 detector positions the calibration based analysis method yielded reliable estimates of the tissue optical properties.

  14. Surface treatments for improved performance and properties

    International Nuclear Information System (INIS)

    Burke, J.J.; Weiss, V.


    This book considers the characteristics, structures, and properties of surfaces. Divides the subject into the physical and chemical characteristics of metallic and nonmetallic surfaces, emerging surface modification techniques, surface structure and mechanical properties, and relationships between properties and processing for nonmetallic materials. Explores various methods of surface modification that can produce improved materials properties. Discusses such wide-ranging topics as the characterization of surfaces, reaction kinetics, the chemistry of gaseous hydrogen embrittlement, the effect of surface modification on corrosion, protection against high-temperature corrosion of surfaces, the effect of high temperatures developed during plating on the microstructure and microhardness of steel, near-surface modifications that will improve the crack-tolerant behavior of high-strength alloys, fretting corrosion and fretting fatigue, surface treatments for enhanced bonding between inorganic surfaces and polymers, and the relationships between surface structure, ceramic processing, and mechanical properties. Recommended for workers and researchers in materials science, surface science, and mechanical engineering. Constitutes the proceedings of the Twenty-sixth Sagamore Army Materials Research Conference (entitled ''Surface Treatments for Improved Performance and Properties'') held in New York in 1979

  15. Transmission/reflection behaviors of surface plasmons at an interface between two plasmonic systems (United States)

    Guan, Fuxin; Sun, Shulin; Ma, Shaojie; Fang, Zhening; Zhu, Baocheng; Li, Xin; He, Qiong; Xiao, Shiyi; Zhou, Lei


    Although surface plasmon polaritons (SPPs) have been intensively studied in past years, the transmission/reflection properties of SPPs at an interface between two plasmonic media are still not fully understood. In this article, we employ a mode expansion method (MEM) to systematically study such a problem based on a model system jointing two superlattices, each consisting of a periodic stacking of dielectric and plasmonic slabs with different material properties. Such a generic model can represent two widely used plasmonic structures (i.e. interfaces between two single dielectric/metal systems or between two metal–insulator–metal waveguides) under certain conditions. Our MEM calculations, in excellent agreement with full-wave simulations, uncover the rich physics behind the SPP reflections at generic plasmonic interfaces. In particular, we successfully derive from the MEM several analytical formulas that can quantitatively describe the SPP reflections at different plasmonic interfaces, and show that our formulas exhibit wider applicable regions than previously proposed empirical ones.

  16. Near Surface Seismic Reflection Imaging: Great Potential Under Critical Eye (United States)

    Miller, R. D.; Peterie, S.; Judy, B. E.


    Seismic-reflection imaging has long been a mainstay in the oil and gas exploration community with mind boggling advancements in just the last decade, but its application to engineering, environmental, and groundwater problems has not seen the same level of utilization. A great deal of the problem lies in the many assumptions that are valid for deep exploration that are violated in the very complex near surface. Large channel systems with acquisition geometries conducive for both deep and shallow targets are many times assumed to be capable of extending the imaging depth window. In reality, constraints of the source and sensor/recording systems must be considered, where large powerful sources are needed to image exploration depths while low-energy, high-frequency sources are required for the shallow and thin targets in the near surface. Attempts to make one size fit all will result in artifacts that result in bogus images and characterizations in the shallow subsurface.Narrow optimum offsets, highly attenuative materials, extreme velocity variability, wavefield interference, and low signal-to-noise ratios provide an ideal breeding ground for the generation of artifacts on near-surface seismic-reflection data. With the cost of shallow reflection data being so high relative to other geophysical methods and invasive sampling, sometimes a single failure can hinder the growth in the use of the method. The method is extremely powerful and has the potential to provide vast quantities of information critical to understand the distributed hydrogeological and biogeochemical processes that elude borehole investigations. It is imperative that data be acquired in its rawest possible form and be processed with an eye to each operation. Cost savings sometimes result in one-size-fits-all acquisition and automated processing flows. Attention to detail and following signal from origination to characterization is essential.

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

    International Nuclear Information System (INIS)

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


    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

  18. Light reflection by road surfaces : english edition of Communication 53 of the Study Centre for Road Construction (Mededeling 53 'lichtreflectie van wegdekken', 1984.

    NARCIS (Netherlands)

    SCW-Working Group E2; Schreuder, D.A. Schram, J. Burghout, F. Kreeft, S.G. van der Tan, T.H. & Gorkum, F. van


    This report deals with the relationship between the light reflecting properties and the composition of road surfaces. For this it is essential to be able to characterise, identify and classify surfaces with regard to their reflection properties. Identification is possible by means of two parameters

  19. A Conceptual Model of Surface Reflectance Estimation for Satellite Remote Sensing Images Using in situ Reference Data

    Directory of Open Access Journals (Sweden)

    Ke-Sheng Cheng


    Full Text Available For satellite remote sensing, radiances received at the sensor are not only affected by the atmosphere but also by the topographic properties of the terrain surface. As a result, atmospheric correction alone does not yield output images that truly reflect terrain surface properties, namely surface reflectance (bidirectional reflectance factor, BRF of objects on the earth surface. Following the concept of the radiometric control area (RCA-based path radiance estimation method, we herein propose a statistical approach for surface reflectance estimation utilizing DEM data and surface reflectance of selected radiometric control areas. An algorithm for identification of shaded samples and a shape factor model were also developed in this study. The proposed RCA-based surface reflectance estimation method is capable of achieving good reflectance estimates in a region where elevation varies from 0 to approximately 600 m above the mean sea level. However, further study is recommended in order to extend the application of the proposed method to areas with substantial terrain variation.

  20. 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)


    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)

  1. Radiative Properties of Smoke and Aerosol Over Land Surfaces (United States)

    King, Michael D.


    This talk discusses smoke and aerosol's radiative properties with particular attention to distinguishing the measurement over clear sky from clouds over land, sea, snow, etc. surfaces, using MODIS Airborne Simulator data from (Brazil, arctic sea ice and tundra and southern Africa, west Africa, and other ecosystems. This talk also discusses the surface bidirectional reflectance using Cloud Absorption Radiometer, BRDF measurements of Saudi Arabian desert, Persian Gulf, cerrado and rain forests in Brazil, sea ice, tundra, Atlantic Ocean, Great Dismal Swamp, Kuwait oil fire smoke. Recent upgrades to instrument (new TOMS UVA channels at 340 and 380 planned use in Africa (SAFARI 2000) and possibly for MEIDEX will also be discussed. This talk also plans to discuss the spectral variation of surface reflectance over land and the sensitivity of off-nadir view angles to correlation between visible near-infrared reflectance for use in remote sensing of aerosol over land.

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

    Directory of Open Access Journals (Sweden)

    O. Salas


    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.

  3. Studies of dust grain properties in infrared reflection nebulae. (United States)

    Pendleton, Y J; Tielens, A G; Werner, M W


    We have developed a model for reflection nebulae around luminous infrared sources embedded in dense dust clouds. The aim of this study is to determine the sizes of the scattering grains. In our analysis, we have adopted an MRN-like power-law size distribution (Mathis, Rumpl, and Nordsieck) of graphite and silicate grains, but other current dust models would give results which were substantially the same. In the optically thin limit, the intensity of the scattered light is proportional to the dust column density, while in the optically thick limit, it reflects the grain albedo. The results show that the shape of the infrared spectrum is the result of a combination of the scattering properties of the dust, the spectrum of the illuminating source, and foreground extinction, while geometry plays a minor role. Comparison of our model results with infrared observations of the reflection nebula surrounding OMC-2/IRS 1 shows that either a grain size distribution like that found in the diffuse interstellar medium, or one consisting of larger grains, can explain the observed shape of the spectrum. However, the absolute intensity level of the scattered light, as well as the observed polarization, requires large grains (approximately 5000 angstroms). By adding water ice mantles to the silicate and graphite cores, we have modeled the 3.08 micrometers ice band feature, which has been observed in the spectra of several infrared reflection nebulae. We show that this ice band arises naturally in optically thick reflection nebulae containing ice-coated grains. We show that the shape of the ice band is diagnostic of the presence of large grains, as previously suggested by Knacke and McCorkle. Comparison with observations of the BN/KL reflection nebula in the OMC-1 cloud shows that large ice grains (approximately 5000 angstroms) contribute substantially to the scattered light.

  4. Interferometry of a reflective axicon surface with a small cone angle using an optical inner surface (United States)

    Gao, Huimin; Zhang, Xiaodong; Fang, Fengzhou


    Reflective axicons, widely used in optical alignment and Bessel-Gauss beam generation, require a highly accurate cone angle and surface metrology. However, current methods focus on the cone angle measurement and it is still difficult to measure the surface of a reflective axicon with a small cone angle. An interferometer measurement method using an optical inner surface is proposed to obtain the surface and cone angle simultaneously. The optical axis of the axicon and the optical inner surface should align together and be parallel to the beam light from the interferometer. The interference fringe would be obtained by the optical system consisting of the axicon and the optical inner surface. The theoretical model is established and analyzed through ray tracing theory, and is verified by optical simulation software. Fabrication errors in the axicon and the inner surface, and misalignment of the measurement setup are investigated systematically and separated in the measurement process. In the experiments, the reflective axicon with a cone angle of about 90° was measured by the proposed method, the results of which show good agreement with a stylus profiler (Taylor-Hobson PGI 3D) in cone angle trend and generatrix error. Experimental results prove the feasibility of the proposed method. This economical and effective method can be widely used with all types of reflective axicons, and it can obtain the surface error map of the axicon as well as the inner cylinder at the same time. The uncertainty and resolution of the proposed method is based on the performance of the interferometer. The uncertainty of alignment angle errors is less than 10-10 rad; the lateral resolution is 53.8 µm.

  5. Interferometry of a reflective axicon surface with a small cone angle using an optical inner surface

    International Nuclear Information System (INIS)

    Gao, Huimin; Zhang, Xiaodong; Fang, Fengzhou


    Reflective axicons, widely used in optical alignment and Bessel–Gauss beam generation, require a highly accurate cone angle and surface metrology. However, current methods focus on the cone angle measurement and it is still difficult to measure the surface of a reflective axicon with a small cone angle. An interferometer measurement method using an optical inner surface is proposed to obtain the surface and cone angle simultaneously. The optical axis of the axicon and the optical inner surface should align together and be parallel to the beam light from the interferometer. The interference fringe would be obtained by the optical system consisting of the axicon and the optical inner surface. The theoretical model is established and analyzed through ray tracing theory, and is verified by optical simulation software. Fabrication errors in the axicon and the inner surface, and misalignment of the measurement setup are investigated systematically and separated in the measurement process. In the experiments, the reflective axicon with a cone angle of about 90° was measured by the proposed method, the results of which show good agreement with a stylus profiler (Taylor-Hobson PGI 3D) in cone angle trend and generatrix error. Experimental results prove the feasibility of the proposed method. This economical and effective method can be widely used with all types of reflective axicons, and it can obtain the surface error map of the axicon as well as the inner cylinder at the same time. The uncertainty and resolution of the proposed method is based on the performance of the interferometer. The uncertainty of alignment angle errors is less than 10 −10 rad; the lateral resolution is 53.8 µ m. (paper)

  6. MODIS/Terra Surface Reflectance 8-Day L3 Global 250m SIN Grid V005 (United States)

    National Aeronautics and Space Administration — The MODIS Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric...

  7. MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid V005 (United States)

    National Aeronautics and Space Administration — The MODIS Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric...

  8. MODIS/Terra Surface Reflectance Daily L2G Global 250m SIN Grid V005 (United States)

    National Aeronautics and Space Administration — The MODIS Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric...

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

    DEFF Research Database (Denmark)

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


    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....

  10. Properties Of Reflection Holograms Recorded In Polaroid's DMP-128 Photopolymer (United States)

    Ingwall, R. T.; Troll, M.; Vetterling, W. T.


    Optical and microstructural properties of reflection holograms recorded in DMP-128 are reported. The optical properties are determined from transmission spectra of the holograms by ignoring the relatively small effects of light scattering and absorption. Microstructure is revealed by light and electron microscopic examination of hologram sections prepared either by diamond grit abrasion or by freeze fracture. Fringe planes are clearly seen with both sectioning procedures. The spacing between adjacent planes is strongly affected by processing conditions. Standard processing produces reflection holograms with fringe plane spacing that decreases continuously from the film:substrate interface to the film:air interface. These holograms have wide spectral bandwidths (100-200nm) and irregular band shapes. Narrow bandwidth holograms are produced from slightly more complicated processing steps. The optical properties of both types of holograms are compared to a theoretical model developed to account for nonuniform fringe plane spacing. Important experimental features such as spectral bandwidth and diffraction efficiency are readily explained by the theory and the observed microstructure.

  11. Surface active monomers synthesis, properties, and application

    CERN Document Server

    Borzenkov, Mykola


    This brief includes information on the background?of and development of synthesis of various types of surface active monomers. The authors explain the importance of utilization of surface active monomers for creation of surface active polymers? and the various biomedical applications of such compounds . This brief introduces techniques for the synthesis of novel types of surface active monomers, their colloidal and polymerizable properties and application for needs of medicine and biology.

  12. Aerosol Optical Retrieval and Surface Reflectance from Airborne Remote Sensing Data over Land

    Directory of Open Access Journals (Sweden)

    Cristiana Bassani


    Full Text Available Quantitative analysis of atmospheric optical properties and surface reflectance can be performed by applying radiative transfer theory in the Atmosphere-Earth coupled system, for the atmospheric correction of hyperspectral remote sensing data. This paper describes a new physically-based algorithm to retrieve the aerosol optical thickness at 550nm (τ550 and the surface reflectance (ρ from airborne acquired data in the atmospheric window of the Visible and Near-Infrared (VNIR range. The algorithm is realized in two modules. Module A retrieves τ550 with a minimization algorithm, then Module B retrieves the surface reflectance ρ for each pixel of the image. The method was tested on five remote sensing images acquired by an airborne sensor under different geometric conditions to evaluate the reliability of the method. The results, τ550 and ρ, retrieved from each image were validated with field data contemporaneously acquired by a sun-sky radiometer and a spectroradiometer, respectively. Good correlation index, r, and low root mean square deviations, RMSD, were obtained for the τ550 retrieved by Module A (r2 = 0.75, RMSD = 0.08 and the ρ retrieved by Module B (r2 ≤ 0.9, RMSD ≤ 0.003. Overall, the results are encouraging, indicating that the method is reliable for optical atmospheric studies and the atmospheric correction of airborne hyperspectral images. The method does not require additional at-ground measurements about at-ground reflectance of the reference pixel and aerosol optical thickness.

  13. Surface composition and surface properties of water hyacinth ...

    African Journals Online (AJOL)

    The surface composition and surface properties of water hyacinth (Eichhornia crassipes) root biomass were studied before and after extraction with dilute nitric acid and toluene/ethanol (2/1, v/v) followed by ethanol, using Fourier Transform Infra-red (FT-IR) spectroscopy, thermogravimetric analysis, x-ray diffraction, ...

  14. The unusual properties of beryllium surfaces

    International Nuclear Information System (INIS)

    Stumpf, R.; Hannon, J.B.


    Be is a ''marginal metal.'' The stable phase, hcp-Be, has a low Fermi-level density of states and very anisotropic structural and elastic properties, similar to a semiconductor's. At the Be(0001) surface, surface states drastically increase the Fermi-level density of states. The different nature of bonding in bulk-Be and at the Be(0001) surface explains the large outward relaxation. The presence of surface states causes large surface core-level shifts by inducing a higher electrostatic potential in the surface layers and by improving the screening at the surface. The authors experimental and theoretical investigations of atomic vibrations at the Be(0001) surface demonstrate clearly that Be screening of atomic motion by the surface states makes the surface phonon dispersion fundamentally different from that of the bulk. Properties of Be(0001) are so different from those of the bulk that the surface can be considered a new ''phase'' of beryllium with unique electronic and structural characteristics. For comparison they also study Be(11 bar 20), a very open surface without important surface states. Be(11 bar 20) is the only clean s-p metal surface known to reconstruct (1 x 3 missing row reconstruction)

  15. ultrasound reflecting the morphological properties in soft tissue

    DEFF Research Database (Denmark)

    Lorentzen, Torben; Larsen, Torben; Court-Payen, Michel


    Ultrasound (US) is an image modality providing the examiner with real-time images which reflect the morphological properties in soft tissue. Different types of transducers are used for different kind of exams. US is cheap, fast, and safe. US is widely used in abdominal imaging including obstetrics...... and gynaecology plus cardiology. Furthermore, US has gained significant interest in rheumatology, orthopaedics and anaesthetics. Colour Doppler and spectral Doppler is useful in vascular imaging. The use of US contrast increases accuracy in liver imaging. US can guide for different interventional procedures....

  16. Defined wetting properties of optical surfaces (United States)

    Felde, Nadja; Coriand, Luisa; Schröder, Sven; Duparré, Angela; Tünnermann, Andreas


    Optical surfaces equipped with specific functional properties have attracted increasing importance over the last decades. In the light of cost reduction, hydrophobic self-cleaning behavior is aspired. On the other side, hydrophilic properties are interesting due to their anti-fog effect. It has become well known that such wetting states are significantly affected by the surface morphology. For optical surfaces, however, this fact poses a problem, as surface roughness can induce light scattering. The generation of optical surfaces with specific wetting properties, hence, requires a profound understanding of the relation between the wetting and the structural surface properties. Thus, our work concentrates on a reliable acquisition of roughness data over a wide spatial frequency range as well as on the comprehensive description of the wetting states, which is needed for the establishment of such correlations. We will present our advanced wetting analysis for nanorough optical surfaces, extended by a vibration-based procedure, which is mainly for understanding and tailoring the wetting behavior of various solid-liquid systems in research and industry. Utilizing the relationships between surface roughness and wetting, it will be demonstrated how different wetting states for hydrophobicity and hydrophilicity can be realized on optical surfaces with minimized scatter losses.

  17. Metrology and properties of engineering surfaces

    CERN Document Server

    Greenwood, J; Chetwynd, D


    Metrology and Properties of Engineering Surfaces provides in a single volume a comprehensive and authoritative treatment of the crucial topics involved in the metrology and properties of engineering surfaces. The subject matter is a central issue in manufacturing technology, since the quality and reliability of manufactured components depend greatly upon the selection and qualities of the appropriate materials as ascertained through measurement. The book can in broad terms be split into two parts; the first deals with the metrology of engineering surfaces and covers the important issues relating to the measurement and characterization of surfaces in both two and three dimensions. This covers topics such as filtering, power spectral densities, autocorrelation functions and the use of Fractals in topography. A significant proportion is dedicated to the calibration of scanning probe microscopes using the latest techniques. The remainder of the book deals with the properties of engineering surfaces and covers a w...

  18. A framework for modeling connections between hydraulics, water surface roughness, and surface reflectance in open channel flows (United States)

    Legleiter, Carl; Mobley, Curtis D.; Overstreet, Brandon


    This paper introduces a framework for examining connections between the flow field, the texture of the air-water interface, and the reflectance of the water surface and thus evaluating the potential to infer hydraulic information from remotely sensed observations of surface reflectance. We used a spatial correlation model describing water surface topography to illustrate the application of our framework. Nondimensional relations between model parameters and flow intensity were established based on a prior flume study. Expressing the model in the spatial frequency domain allowed us to use an efficient Fourier transform-based algorithm for simulating water surfaces. Realizations for both flume and field settings had water surface slope distributions positively correlated with velocity and water surface roughness. However, most surface facets were gently sloped and thus unlikely to yield strong specular reflections; the model exaggerated the extent of water surface features, leading to underestimation of facet slopes. A ray tracing algorithm indicated that reflectance was greatest when solar and view zenith angles were equal and the sensor scanned toward the Sun to capture specular reflections of the solar beam. Reflected energy was concentrated in a small portion of the sky, but rougher water surfaces reflected rays into a broader range of directions. Our framework facilitates flight planning to avoid surface-reflected radiance while mapping other river attributes, or to maximize this component to exploit relationships between hydraulics and surface reflectance. This initial analysis also highlighted the need for improved models of water surface topography in natural rivers.

  19. A framework for modeling connections between hydraulics, water surface roughness, and surface reflectance in open channel flows (United States)

    Legleiter, Carl J.; Mobley, Curtis D.; Overstreet, Brandon T.


    This paper introduces a framework for examining connections between the flow field, the texture of the air-water interface, and the reflectance of the water surface and thus evaluating the potential to infer hydraulic information from remotely sensed observations of surface reflectance. We used a spatial correlation model describing water surface topography to illustrate the application of our framework. Nondimensional relations between model parameters and flow intensity were established based on a prior flume study. Expressing the model in the spatial frequency domain allowed us to use an efficient Fourier transform-based algorithm for simulating water surfaces. Realizations for both flume and field settings had water surface slope distributions positively correlated with velocity and water surface roughness. However, most surface facets were gently sloped and thus unlikely to yield strong specular reflections; the model exaggerated the extent of water surface features, leading to underestimation of facet slopes. A ray tracing algorithm indicated that reflectance was greatest when solar and view zenith angles were equal and the sensor scanned toward the Sun to capture specular reflections of the solar beam. Reflected energy was concentrated in a small portion of the sky, but rougher water surfaces reflected rays into a broader range of directions. Our framework facilitates flight planning to avoid surface-reflected radiance while mapping other river attributes, or to maximize this component to exploit relationships between hydraulics and surface reflectance. This initial analysis also highlighted the need for improved models of water surface topography in natural rivers.

  20. Bi-directional Reflectance of Icy Surface Analogs: A Dual Approach (United States)

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


    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 0.1reflectance measurements for NaCl and KCl of sizes from 20reflectance applications beyond astronomy and planetary science. The objective of the experiment was to determine the particle size that provided optimal, or maximum, reflectance for each compound. Our conclusions bring confirmation and clarity to photometric sciences.

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

    Directory of Open Access Journals (Sweden)

    Komačka Jozef


    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.

  2. Excimer laser surface modification: Process and properties

    Energy Technology Data Exchange (ETDEWEB)

    Jervis, T.R.; Nastasi, M. [Los Alamos National Lab., NM (United States); Hirvonen, J.P. [Technical Research Institute, Espoo (Finland). Metallurgy Lab.


    Surface modification can improve materials for structural, tribological, and corrosion applications. Excimer laser light has been shown to provide a rapid means of modifying surfaces through heat treating, surface zone refining, and mixing. Laser pulses at modest power levels can easily melt the surfaces of many materials. Mixing within the molten layer or with the gas ambient may occur, if thermodynamically allowed, followed by rapid solidification. The high temperatures allow the system to overcome kinetic barriers found in some ion mixing experiments. Alternatively, surface zone refinement may result from repeated melting-solidification cycles. Ultraviolet laser light couples energy efficiently to the surface of metallic and ceramic materials. The nature of the modification that follows depends on the properties of the surface and substrate materials. Alloying from both gas and predeposited layer sources has been observed in metals, semiconductors, and ceramics as has surface enrichment of Cr by zone refinement of stainless steel. Rapid solidification after melting often results in the formation of nonequilibrium phases, including amorphous materials. Improved surface properties, including tribology and corrosion resistance, are observed in these materials.

  3. Mercapto-based coupling agent for improved thermophotovoltaic device back surface reflector adhesion and reflectance

    Energy Technology Data Exchange (ETDEWEB)

    Wernsman, Bernard; Fiedor, Joseph N.; Irr, Lawrence G.; Palmisiano, Marc N.


    A back surface reflector (BSR) is described. The BSR includes a reflecting layer, a substrate and an adhesion layer between the reflecting layer and the substrate. The adhesion layer includes 3-mercaptopropyl (trimethoxy) silane (a.k.a. Merc).

  4. Measurements of long-range interactions between protein-functionalized surfaces by total internal reflection microscopy. (United States)

    Wang, Zhaohui; Gong, Xiangjun; Ngai, To


    Understanding the interaction between protein-functionalized surfaces is an important subject in a variety of protein-related processes, ranging from coatings for biomedical implants to targeted drug carriers and biosensors. In this work, utilizing a total internal reflection microscope (TIRM), we have directly measured the interactions between micron-sized particles decorated with three types of common proteins concanavalin A (ConA), bovine serum albumin (BSA), lysozyme (LYZ), and glass surface coated with soy proteins (SP). Our results show that the protein adsorption greatly affects the charge property of the surfaces, and the interactions between those protein-functionalized surfaces depend on solution pH values. At pH 7.5-10.0, all these three protein-functionalized particles are highly negatively charged, and they move freely above the negatively charged SP-functionalized surface. The net interaction between protein-functionalized surfaces captured by TIRM was found as a long-range, nonspecific double-layer repulsion. When pH was decreased to 5.0, both protein-functionalized surfaces became neutral and double-layer repulsion was greatly reduced, resulting in adhesion of all three protein-functionalized particles to the SP-functionalized surface due to the hydrophobic attraction. The situation is very different at pH = 4.0: BSA-decorated particles, which are highly charged, can move freely above the SP-functionalized surfaces, while ConA- and LYZ-decorated particles can only move restrictively in a limited range. Our results quantify these nonspecific kT-scale interactions between protein-functionalized surfaces, which will enable the design of surfaces for use in biomedical applications and study of biomolecular interactions.

  5. Reflectance and thermal properties of the urban fabric studied with aerial spectral imaging (United States)

    Burud, Ingunn; Thiis, Thomas; Gaitani, Niki


    The properties of materials used in the urban fabric play an essential role to the microclimate. Their thermal performance, one of the main impacting factors to urban heat island effects, is mainly determined by the physical characteristics, optical and thermal. The present research approach aims at analyzing the relation between material properties and their thermal behavior using airborne multispectral imaging in VIS/NIR and IR with sensors mounted on Unmanned Aerial Vehicle (UAV), at a survey in Athens. The images have been combined to form maps of surface temperature distribution and of material properties. Normalized Differential Vegetation Index (NDVI) maps were computed from the VIS/NIR images and were used to classify the surface material. Calibration of the temperatures was obtained by applying correct emissivity for different materials from the classified surface material map. Maps of estimated albedo and of apparent thermal inertia were derived from the VIS/NIR images and the temperature images. Combining the surface temperature maps with maps of NDVI, albedo and apparent thermal inertia makes it is possible to identify reflectance characteristics of a variety materials utilized in the urban setting in Athens and to relate these to their thermal properties. The applied multisensory technique demonstrates how novel advances in sensor development combined with advanced data analysis provide new and unique tools for urban climate studies. The results give new perspectives of urban features for revealing the complex mechanisms that lead to microclimatic modifications and to quantify their relative contribution.

  6. Reconstruction of Satellite-Retrieved Land-Surface Reflectance Based on Temporally-Continuous Vegetation Indices

    Directory of Open Access Journals (Sweden)

    Zhiqiang Xiao


    Full Text Available Land-surface reflectance, estimated from satellite observations through atmospheric corrections, is an essential parameter for further retrieval of various high level land-surface parameters, such as leaf area index (LAI, fraction of absorbed photosynthetically active radiation (FAPAR, and surface albedo. Although great efforts have been made, land-surface reflectance products still contain considerable noise caused by, e.g., cloud or mixed-cloud pixels, which results in temporal and spatial inconsistencies in subsequent downstream products. In this study, a new method is developed to remove the residual clouds in the Moderate Resolution Imaging Spectroradiometer (MODIS land-surface reflectance product and reconstruct time series of surface reflectance for the red, near infrared (NIR, and shortwave infrared (SWIR bands. A smoothing method is introduced to calculate upper envelopes of vegetation indices (VIs from the surface reflectance data and the cloud contaminated reflectance data are identified using the time series VIs and the upper envelopes of the time series VIs. Surface reflectance was then reconstructed according to cloud-free surface reflectance by incorporating the upper envelopes of the time series VIs as constraint conditions. The method was applied to reconstruct time series of surface reflectance from MODIS/TERRA surface reflectance product (MOD09A1. Temporal consistency analysis indicates that the new method can reconstruct temporally-continuous time series of land-surface reflectance. Comparisons with cloud-free MODIS/AQUA surface reflectance product (MYD09A1 over the BELMANIP (Benchmark Land Multisite Analysis and Intercomparison of Products sites in 2003 demonstrate that the new method provides better performance for the red band (R2 = 0.8606 and RMSE = 0.0366 and NIR band (R2 = 0.6934 and RMSE = 0.0519, than the time series cloud detection (TSCD algorithm (R2 = 0.5811 and RMSE = 0.0649; and R2 = 0.5005 and RMSE = 0

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


    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

  8. Surface Properties of TNOs: Preliminary Statistical Analysis (United States)

    Antonieta Barucci, Maria; Fornasier, S.; Alvarez-Cantal, A.; de Bergh, C.; Merlin, F.; DeMeo, F.; Dumas, C.


    An overview of the surface properties based on the last results obtained during the Large Program performed at ESO-VLT (2007-2008) will be presented. Simultaneous high quality visible and near-infrared spectroscopy and photometry have been carried out on 40 objects with various dynamical properties, using FORS1 (V), ISAAC (J) and SINFONI (H+K bands) mounted respectively at UT2, UT1 and UT4 VLT-ESO telescopes (Cerro Paranal, Chile). For spectroscopy we computed the spectral slope for each object and searched for possible rotational inhomogeneities. A few objects show features in their visible spectra such as Eris, whose spectral bands are displaced with respect to pure methane-ice. We identify new faint absorption features on 10199 Chariklo and 42355 Typhon, possibly due to the presence of aqueous altered materials. The H+K band spectroscopy was performed with the new instrument SINFONI which is a 3D integral field spectrometer. While some objects show no diagnostic spectral bands, others reveal surface deposits of ices of H2O, CH3OH, CH4, and N2. To investigate the surface properties of these bodies, a radiative transfer model has been applied to interpret the entire 0.4-2.4 micron spectral region. The diversity of the spectra suggests that these objects represent a substantial range of bulk compositions. These different surface compositions can be diagnostic of original compositional diversity, interior source and/or different evolution with different physical processes affecting the surfaces. A statistical analysis is in progress to investigate the correlation of the TNOs’ surface properties with size and dynamical properties.

  9. Enhancement of surface properties for coal beneficiation

    Energy Technology Data Exchange (ETDEWEB)

    Chander, S.; Aplan, F.F.


    This report will focus on means of pyrite removal from coal using surface-based coal cleaning technologies. The major subjects being addressed in this study are the natural and modulated surface properties of coal and pyrite and how they may best be utilized to facilitate their separation using advanced surface-based coal cleaning technology. Emphasis is based on modified flotation and oil agglomerative processes and the basic principles involved. The four areas being addressed are: (1) Collectorless flotation of pyrite; (2) Modulation of pyrite and coal hydrophobicity; (3) Emulsion processes and principles; (4) Evaluation of coal hydrophobicity.

  10. 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

  11. Surface reflectance drives nest box temperature profiles and thermal suitability for target wildlife. (United States)

    Griffiths, Stephen R; Rowland, Jessica A; Briscoe, Natalie J; Lentini, Pia E; Handasyde, Kathrine A; Lumsden, Linda F; Robert, Kylie A


    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 shade profiles (i

  12. Enhanced Group Delay of the Pulse Reflection with Graphene Surface Plasmon via Modified Otto Configuration

    Directory of Open Access Journals (Sweden)

    Guimei Li


    Full Text Available In this paper, the group delay of the transverse magnetic (TM polarized wave reflected from a modified Otto configuration with graphene surface plasmon is investigated theoretically. The findings show that the optical group delay in this structure can be enhanced negatively and can be switched from negative to positive due to the excitation of surface plasmon by graphene. It is clear that the negative group delay can be actively tuned through the Fermi energy of the graphene. Furthermore, the delay properties can also be manipulated by changing either the relaxation time of graphene or the distance between the coupling prism and the graphene. These tunable delay characteristics are promising for fabricating grapheme-based optical delay devices and other applications in the terahertz regime.

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

    KAUST Repository

    Nafe, Mahmoud


    . 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.

  14. Monte Carlo simulation of light reflection from cosmetic powder particles near the human skin surface. (United States)

    Okamoto, Takashi; Kumagawa, Tatsuya; Motoda, Masafumi; Igarashi, Takanori; Nakao, Keisuke


    The reflection and scattering properties of light incident on human skin covered with powder particles have been investigated. A three-layer skin structure with a pigmented area is modeled, and the propagation of light in the skin's layers and in a layer of particles near the skin's surface is simulated using the Monte Carlo method. Assuming that only single scattering of light occurs in the powder layer, the simulation results show that the reflection spectra of light from the skin change with the size of powder particles. The color difference between normal and discolored skin is found to decrease considerably when powder particles with a diameter of approximately 0.25 μm are present near the skin's surface. The effects of the medium surrounding the particles, and the influence of the distribution of particle size (polydispersity), are also examined. It is shown that a surrounding medium with a refractive index close to that of the skin substantially suppresses the extreme spectral changes caused by the powder particles covering the skin surface.

  15. VIIRS/NPP Surface Reflectance 8-Day L3 Global 500m SIN Grid V001 (United States)

    National Aeronautics and Space Administration — The 8-day Visible Infrared Imaging Radiometer Suite (VIIRS) Surface Reflectance (VNP09H1) Version 1 composite product provides an estimate of land surface...

  16. Correlation between surface microstructure and optical properties of porous silicon

    Directory of Open Access Journals (Sweden)

    Saeideh Rhramezani Sani


    Full Text Available   We have studied the effect of increasing porosity and its microstructure surface variation on the optical and dielectric properties of porous silicon. It seems that porosity, as the surface roughness within the range of a few microns, shows quantum effect in the absorption and reflection process of porous silicon. Optical constants of porous silicon at normal incidence of light with wavelength in the range of 250-3000 nm have been calculated by Kramers-Kroning method. Our experimental analysis shows that electronic structure and dielectric properties of porous silicon are totally different from silicon. Also, it shows that porous silicon has optical response in the visible region. This difference was also verified by effective media approximation (EMA.

  17. Surface active properties of lipid nanocapsules.

    Directory of Open Access Journals (Sweden)

    Celia R A Mouzouvi

    Full Text Available Lipid nanocapsules (LNCs are biomimetic nanocarriers used for the encapsulation of a broad variety of active ingredients. Similar to surface active compounds, LNCs contain both hydrophilic and hydrophobic parts in their structure. Moreover, the components of LNCs, macrogol 15 hydroxystearate (MHS and lecithin, are known for their surface active properties. Therefore, the aim of this paper was to investigate the capability of the LNCs to decrease surface tension using two techniques: drop tensiometry and the Wilhelmy plate method. LNCs with diameters ranging from 30 to 100 nm were successfully obtained using a phase inversion technique. The LNCs' properties, such as size and zeta potential, depend on the composition. LNCs exhibit a lower limiting surface tension compared to MHS (34.8-35.0 mN/m and 37.7-38.8 mN/m, respectively, as confirmed by both drop tensiometry and the Wilhelmy plate method. LNCs have exhibited a saturated interfacial concentration (SIC that was 10-fold higher than the critical micellar concentration (CMC of MHS or the SIC of binary and ternary mixtures of LNC ingredients. The SIC of the LNC formulations depended on the mass mixing ratio of the MHS/triglycerides but not on the presence of lecithin. The CMC/SIC values measured by the Wilhelmy plate method were higher than those obtained using drop tensiometry because of the longer duration of the tensiometry measurement. In conclusion, the surfactant-like properties of the LNCs offer new possibilities for medical and pharmaceutical applications.

  18. Light Reflection from Water Surfaces Perturbed by Falling Rain Droplets (United States)

    Molesini, Giuseppe; Vannoni, Maurizio


    An account of peculiar light patterns produced by reflection in a pool under falling rain droplets was recently reported by Molesini and Vannoni (2008 Eur. J. Phys. 29 403-11). The mathematical approach, however, only covered the case of a symmetrical location of a light source and the observer's eyes with respect to the vertical of the falling…

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

    KAUST Repository

    Houborg, Rasmus


    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

  20. Characterizing the statistical properties of protein surfaces (United States)

    Bak, Ji Hyun; Bitbol, Anne-Florence; Bialek, William

    Proteins and their interactions form the body of the signaling transduction pathway in many living systems. In order to ensure the accuracy as well as the specificity of signaling, it is crucial that proteins recognize their correct interaction partners. How difficult, then, is it for a protein to discriminate its correct interaction partner(s) from the possibly large set of other proteins it may encounter in the cell? An important ingredient of recognition is shape complementarity. The ensemble of protein shapes should be constrained by the need for maintaining functional interactions while avoiding spurious ones. To address this aspect of protein recognition, we consider the ensemble of proteins in terms of the shapes of their surfaces. We take into account the high-resolution structures of E.coli non-DNA-binding cytoplasmic proteins, retrieved from the Protein Data Bank. We aim to characterize the statistical properties of the protein surfaces at two levels: First, we study the intrinsic dimensionality at the level of the ensemble of the surface objects. Second, at the level of the individual surfaces, we determine the scale of shape variation. We further discuss how the dimensionality of the shape space is linked to the statistical properties of individual protein surfaces. Jhb and WB acknowledge support from National Science Foundation Grants PHY-1305525 and PHY-1521553. AFB acknowledges support from the Human Frontier Science Program.

  1. Welcome to Surface Topography: Metrology and Properties (United States)

    Leach, Richard


    I am delighted to welcome readers to this inaugural issue of Surface Topography: Metrology and Properties (STMP). In these days of citation indexes and academic reviews, it is a tough, and maybe a brave, job to start a new journal. But the subject area has never been more active and we are seeing genuine breakthroughs in the use of surfaces to control functional performance. Most manufactured parts rely on some form of control of their surface characteristics. The surface is usually defined as that feature on a component or device, which interacts with either the environment in which it is housed (or in which the device operates), or with another surface. The surface topography and material characteristics of a part can affect how fluids interact with it, how the part looks and feels and how two bearing parts will slide together. The need to control, and hence measure, surface features is becoming increasingly important as we move into a miniaturized world. Surface features can become the dominant functional features of a part and may become large in comparison to the overall size of an object. Research into surface texture measurement and characterization has been carried out for over a century and is now more active than ever, especially as new areal surface texture specification standards begin to be introduced. The range of disciplines for which the function of a surface relates to its topography is very diverse; from metal sheet manufacturing to art restoration, from plastic electronics to forensics. Until now, there has been no obvious publishing venue to bring together all these applications with the underlying research and theory, or to unite those working in academia with engineering and industry. Hence the creation of Surface Topography: Metrology and Properties . STMP will publish the best work being done across this broad discipline in one journal, helping researchers to share common themes and highlighting and promoting the extraordinary benefits this

  2. Orientation effect of ion flux splitting reflected from Wehner cone on solid surface

    CERN Document Server

    Bratchenko, M I; Rozhkov, V V


    It is shown that simple geometrical model of specular reflection of particles from the surface of Wehner cone (frequently observed feature of solid surface macroscopic topography developed under ion bombardment) can describe qualitatively the essential characteristics of the reflected particles flux splitting effect predicted earlier by means of computer simulation methods.

  3. A Monte Carlo reflectance model for soil surfaces with three-dimensional structure (United States)

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


    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.

  4. Liquid Atomization Induced by Pulse Laser Reflection underneath Liquid Surface (United States)

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


    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.

  5. Oxides Surfaces and Novel Electronic Properties (United States)

    Koirala, Pratik

    The scope of this thesis extends to the study of surface structures and electronic properties in a number of complex oxides. The c(6x2) surface reconstruction on SrTiO3 (001) was solved using a combination of plan view transmission electron microscopy imaging, atomic resolution secondary electron imaging, and density functional theory calculations. This work provided fundamental insights on the effects of dielectric screening in secondary electron generation. A thorough analysis on the limitation and functionality of transmission plan view imaging showed that the kinematical approximations used in the separation of top and bottom surfaces is only valid in thin samples (˜5 nm or less for SrTiO3). The presence of an inversion center in the surface structure also made separation of the top and bottom surfaces more robust. Surface studies of two other oxides, KTaO3 and NdGaO3, provided understanding on the mechanism of surface heterogeneity and segregation. In the case of KTaO3, selective ion sputtering and the loss of K resulted in large stoichiometric variations at the surface. Annealing of such samples led to the formation of a potassium deficient tetragonal phase (K 6Ta10.8O30) on the surface. A similar phenomenon was also observed in NdGaO3. Exploratory surface studies of the rare earth scandates (ReScO3 , Re = Gd, Tb, Dy) led to the observation of large flexoelectric bending inside an electron microscope. Thin rods of these scandates bent by up to 90 degree under a focused electron beam; the bending was fully reversible. Ex-situ measurements of flexoelectric coe cient performed by an- other graduate student, Christopher Mizzi, confirmed that the scandates have a large flexocoupling voltage (˜42 V). Electronic structure of the lanthanide scandates was studied using temperature depen- dent X-ray photoelectron spectroscopy and hybrid density functional theory calculations. The amount of charging under X-ray illumination was greatly reduced with increasing

  6. 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


    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.

  7. Infrared reflection properties and modelling of in situ reflection measurements on plasma-facing materials in Tore Supra

    International Nuclear Information System (INIS)

    Reichle, R; Desgranges, C; Faisse, F; Pocheau, C; Lasserre, J-P; Oelhoffen, F; Eupherte, L; Todeschini, M


    Tore Supra has-like ITER-reflecting internal surfaces, which can perturb the machine protection systems based on infrared (IR) thermography. To ameliorate this situation, we have measured and modelled in the 3-5 μm wavelength range the bi-directional reflection distribution function (BRDF) of wall material samples from Tore Supra and conducted in situ reflection measurements and simulated them with the CEA COSMOS code. BRDF results are presented for B 4 C and carbon fibre composite (CFC) tiles. The hemispherical integrated reflection ranges from 0.12 for the B 4 C sample to 0.39 for a CFC tile from the limiter erosion zone. In situ measurements of the IR reflection of a blackbody source off an ICRH and an LHCD antenna of Tore Supra are well reproduced by the simulation.

  8. Assessing the Psychometric Properties of Kember and Leung's Reflection Questionnaire (United States)

    Lethbridge, Kristen; Andrusyszyn, Mary-Anne; Iwasiw, Carroll; Laschinger, Heather K. S.; Fernando, Rajulton


    Reflective thinking is often stated as a learning outcome of baccalaureate nursing education, and as a characteristic of a competent professional; however, no consistent method exists to assess the extent to which students engage in reflective thinking. To address this need, Kember and Leung developed and tested a self-report questionnaire based…

  9. Anisotropic surface chemistry properties and adsorption behavior of silicate mineral crystals. (United States)

    Xu, Longhua; Tian, Jia; Wu, Houqin; Fang, Shuai; Lu, Zhongyuan; Ma, Caifeng; Sun, Wei; Hu, Yuehua


    Anisotropic surface properties of minerals play an important role in a variety of fields. With a focus on the two most intensively investigated silicate minerals (i.e., phyllosilicate minerals and pegmatite aluminosilicate minerals), this review highlights the research on their anisotropic surface properties based on their crystal structures. Four surface features comprise the anisotropic surface chemistry of minerals: broken bonds, energy, wettability, and charge. Analysis of surface broken bond and energy anisotropy helps to explain the cleavage and growth properties of mineral crystals, and understanding surface wettability and charge anisotropy is critical to the analysis of minerals' solution behavior, such as their flotation performance and rheological properties. In a specific reaction, the anisotropic surface properties of minerals are reflected in the adsorption strengths of reagents on different mineral surfaces. Combined with the knowledge of mineral crushing and grinding, a thorough understanding of the anisotropic surface chemistry properties and the anisotropic adsorption behavior of minerals will lead to the development of effective relational models comprising their crystal structure, surface chemistry properties, and targeted reagent adsorption. Overall, such a comprehensive approach is expected to firmly establish the connection between selective cleavage of mineral crystals for desired surfaces and designing novel reagents selectively adsorbed on the mineral surfaces. As tools to characterize the anisotropic surface chemistry properties of minerals, DLVO theory, atomic force microscopy (AFM), and molecular dynamics (MD) simulations are also reviewed. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Removal of Surface-Reflected Light for the Measurement of Remote-Sensing Reflectance from an Above-Surface Platform (United States)


    REPORT DATE IDD-MM- YYYY) 14-02-2011 2. REPORT TYPE Journal Article 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Removal of Surface...impossible to obtain Rr, from measurements of vertical profiles of Lu and Elt [6]. During the experiment, the surface was calm [see Fig. 8(a)] and

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

    KAUST Repository

    Xu, Yanlong


    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.

  12. Preparation of polybutylene terephthalate/silica nanocomposites by melt compounding: Evaluation of surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Hajiraissi, Roozbeh [Young Researchers Club, Islamic Azad University, Bushehr Branch, Bushehr (Iran, Islamic Republic of); Parvinzadeh, Mazeyar, E-mail: [Department of Textile, Islamic Azad University, Shahre Rey Branch, Tehran (Iran, Islamic Republic of)


    Influence of nanosilica on surface properties of poly(butylene terephthalate) was investigated by the use of Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), contact angle measurement (CAM), scanning electron microscopy (SEM) and reflectance spectroscopy (RS). FTIR results indicated that surface groups of silica have some interfacial interactions and bonding with carboxyl or hydroxyl end groups of PBT chains. AFM and SEM figures of the resultant nanocomposites illustrated increased surface roughness compared to pure PBT. Optical properties of nanocomposite films were finally determined by the aid of reflectance spectrophotometer.

  13. Estimating aerodynamic resistance of rough surfaces from angular reflectance (United States)

    Current wind erosion and dust emission models neglect the heterogeneous nature of surface roughness and its geometric anisotropic effect on aerodynamic resistance, and over-estimate the erodible area by assuming it is not covered by roughness elements. We address these shortfalls with a new model wh...

  14. Measurements of TYVEK reflective properties for the Pierre Auger Project

    Energy Technology Data Exchange (ETDEWEB)

    Gichaba, Justus Ogwoka; /Mississippi U.


    The authors have measured the spectrum and diffuse reflection of various samples of Tyvek, a material to be used to line the inner walls of the Pierre Auger Observatory water crenkov tanks. These measurements were carried out with a Lambda 18 UV/VIS spectrometer over a wavelength range from 200 nm to 700 nm. The angular dependence of this scattering was a gaussian. They have also carried the measurements with the PASCO OS-8020 to find the reflectivity of Tyvek samples versus Incident and Reflected angles. The reflected angles range from -90{sup o} to -90{sup o}. Finally, information from these measurements was used to simulate Cosmic rays events in a Water Cerenkov detector.


    Directory of Open Access Journals (Sweden)

    Montes V. Luis A.


    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.

  16. Hydrodynamic slip length as a surface property (United States)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.


    Equilibrium and nonequilibrium molecular dynamics simulations were conducted in order to evaluate the hypothesis that the hydrodynamic slip length is a surface property. The system under investigation was water confined between two graphite layers to form nanochannels of different sizes (3-8 nm). The water-carbon interaction potential was calibrated by matching wettability experiments of graphitic-carbon surfaces free of airborne hydrocarbon contamination. Three equilibrium theories were used to calculate the hydrodynamic slip length. It was found that one of the recently reported equilibrium theories for the calculation of the slip length featured confinement effects, while the others resulted in calculations significantly hindered by the large margin of error observed between independent simulations. The hydrodynamic slip length was found to be channel-size independent using equilibrium calculations, i.e., suggesting a consistency with the definition of a surface property, for 5-nm channels and larger. The analysis of the individual trajectories of liquid particles revealed that the reason for observing confinement effects in 3-nm nanochannels is the high mobility of the bulk particles. Nonequilibrium calculations were not consistently affected by size but by noisiness in the smallest systems.

  17. Surface Bubbles in the Bathtub and Reflections on Ripple Tanks (United States)

    Greenslade, Thomas B.


    Bathtubs are splendid places for studying physics! Recently I was happily splashing about and noticed that the light from the lamp above me was being focused as bright spots on the bottom of the tub. Closer inspection showed that the spots were surrounded by dark rings. This pattern turned out to be due to the lensing effect of bubbles floating on the surface of the water.

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

    Directory of Open Access Journals (Sweden)

    J. F. Burkhart


    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.

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

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


    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.

  20. 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


    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.

  1. Surface properties of copper based cermet materials

    International Nuclear Information System (INIS)

    Voinea, M.; Vladuta, C.; Bogatu, C.; Duta, A.


    The paper presents the characterization of the surface properties of copper based cermets obtained by two different techniques: spray pyrolysis deposition (SPD) and electrodeposition. Copper acetate was used as precursor of Cu/CuO x cermet. The surface morphology was tailored by adding copolymers of maleic anhydride with controlled hydrophobia. The films morphology of Cu/CuO x was assessed using contact angle measurements and AFM analysis. The porous structures obtained via SPD lead to higher liquid adsorption rate than the electrodeposited films. A highly polar liquid - water is recommended as testing liquid in contact angle measurements, for estimating the porosity of copper based cermets, while glycerol can be used to distinguish among ionic and metal predominant structures. Thus, contact angle measurements can be used for a primary evaluation of the films morphology and, on the other hand, of the ratio between the cermet components

  2. Surface properties of copper based cermet materials

    Energy Technology Data Exchange (ETDEWEB)

    Voinea, M. [The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 (Romania)], E-mail:; Vladuta, C.; Bogatu, C.; Duta, A. [The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 (Romania)


    The paper presents the characterization of the surface properties of copper based cermets obtained by two different techniques: spray pyrolysis deposition (SPD) and electrodeposition. Copper acetate was used as precursor of Cu/CuO{sub x} cermet. The surface morphology was tailored by adding copolymers of maleic anhydride with controlled hydrophobia. The films morphology of Cu/CuO{sub x} was assessed using contact angle measurements and AFM analysis. The porous structures obtained via SPD lead to higher liquid adsorption rate than the electrodeposited films. A highly polar liquid - water is recommended as testing liquid in contact angle measurements, for estimating the porosity of copper based cermets, while glycerol can be used to distinguish among ionic and metal predominant structures. Thus, contact angle measurements can be used for a primary evaluation of the films morphology and, on the other hand, of the ratio between the cermet components.

  3. Scaling properties in single collision model of light ion reflection

    International Nuclear Information System (INIS)

    Vukanic, J.; Simovic, R.


    Light ion reflection from solids in the keV energy region has been studied within the single collision model. Particle and energy reflection coefficients as functions of the scaled transport cross section have been calculated numerically by utilizing the exact scattering function for the Kr-C potential and analytically with an effective power approximation for the same potential. The obtained analytical formulae approximate very accurately to the numerical results. Comparison of the calculated reflection coefficients with the experimental data and computer simulations for different light ion-heavy target combinations shows that the scaled transport cross section remains a convenient scaling parameter in the single collision domain, as adopted previously in multiple collision theory

  4. LBA-ECO CD-34 Hyperion 30-m Surface Reflectance, Amazon Basin: 2002-2005 (United States)

    National Aeronautics and Space Administration — This data set contains 20 multispectral surface reflectance images collected by the EO-1 satellite Hyperion sensor at 30-m resolution and covering the entire Amazon...

  5. MODIS/Terra Surface Reflectance Daily L2G Global 250m SIN Grid V006 (United States)

    National Aeronautics and Space Administration — The MOD09GQ Version 6 product provides an estimate of the surface spectral reflectance of Terra MODIS 250 m bands 1-2 corrected for atmospheric conditions such as...

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

  7. CLPX-Satellite: EO-1 Hyperion Surface Reflectance, Snow-Covered Area, and Grain Size (United States)

    National Aeronautics and Space Administration — This data set consists of apparent surface reflectance, subpixel snow-covered area and grain size collected from the Hyperion hyperspectral imager. The Hyperion...

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

  9. ASTER L2 Surface Reflectance VNIR and Crosstalk Corrected SWIR V003 (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...

  10. MODIS/Aqua Surface Reflectance 8-Day L3 Global 250m SIN Grid V006 (United States)

    National Aeronautics and Space Administration — The MYD09Q1 Version 6 product provides an estimate of the surface spectral reflectance of AQUA MODIS Bands 1-2 corrected for atmospheric conditions such as gasses,...

  11. MODIS/Aqua Surface Reflectance Daily L3 Global 0.05Deg CMG V006 (United States)

    National Aeronautics and Space Administration — The MYD09CMG Version 6 product provides an estimate of the surface spectral reflectance of AQUA MODIS Bands 1-7 resampled to 5600 m pixel resolution and corrected...

  12. VIIRS/NPP Surface Reflectance Daily L3 Global 0.05 Deg CMG V001 (United States)

    National Aeronautics and Space Administration — The Visible Infrared Imaging Radiometer Suite (VIIRS) daily surface reflectance Climate Modeling Grid (VNP09CMG) Version 1 product provides an estimate of land...

  13. MODIS/Aqua Surface Reflectance 8-Day L3 Global 500m SIN Grid V006 (United States)

    National Aeronautics and Space Administration — The MYD09A1 Version 6 product provides an estimate of the surface spectral reflectance of AQUA MODIS Bands 1-7 corrected for atmospheric conditions such as gasses,...

  14. LBA-ECO LC-18 Hyperion 30-m Surface Reflectance, Mato Grosso, Brazil: July 2004 (United States)

    National Aeronautics and Space Administration — ABSTRACT: This image was collected by the Hyperion sensor on 10-July-2004 at 13:16:16 GMT. It was calibrated to apparent surface reflectance using the ACORN...

  15. LBA-ECO LC-18 Hyperion 30-m Surface Reflectance, Mato Grosso, Brazil: July 2004 (United States)

    National Aeronautics and Space Administration — This image was collected by the Hyperion sensor on 10-July-2004 at 13:16:16 GMT. It was calibrated to apparent surface reflectance using the ACORN atmospheric...

  16. Hemispherical Reflectance and Emittance Properties of Carbon Nanotubes Coatings at Far-Infrared Wavelengths (United States)

    Quijada, Manuel A.; Hagopian, John G.; Getty, Stephanie; Kinzer, Raymond (Robin) E., Jr.; Wollack, Edward


    Recent visible wavelength observations of Multiwalled Carbon Nanotubes (MWCNT) coatings have revealed that they represent the blackest materials known in nature with a Total Hemispherical Reflectance (THR) less than .25%. This makes them as exceptionally good absorbers, with the potential to provide order-of-magnitude improvement in stray-light suppression over current black surface treatments when used in an optical system. Here we extend the characterization of this class of materials into the infrared spectral region to further evaluate their potential for use on instrument baffles for stray-light suppression and to manage spacecraft thermal properties to dissipate heat through radiant heat transfer process. These characterizations will include the wavelength-dependent Total Hemispherical Reflectance properties in the mid-IR and far-infrared spectral regions (2-100 micrometers). Determination of the temperature-dependent emittance will be investigated in the temperature range of 20 to 300 K. These results will be compared against other more conventional black coatings such as Acktar Fractal Black or Z-306 coatings among others.

  17. Simulation and Measurement of Angle Resolved Reflectance from Black Si Surfaces

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Wu, Kaiyu; Schmidt, Michael Stenbæk


    In this work angle-resolved reflectance from nanostructured Si surfaces realized by maskless RIE texturing has been simulated and measured. The simulation and experimental measurement data show the same trend. Experimentally a total reflectance below 1% for incident angles below 30o and specular...

  18. Backscattered EM-wave manipulation using low cost 1-bit reflective surface at W-band (United States)

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


    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.

  19. Physicochemical properties of concentrated Martian surface waters (United States)

    Tosca, Nicholas J.; McLennan, Scott M.; Lamb, Michael P.; Grotzinger, John P.


    Understanding the processes controlling chemical sedimentation is an important step in deciphering paleoclimatic conditions from the rock records preserved on both Earth and Mars. Clear evidence for subaqueous sedimentation at Meridiani Planum, widespread saline mineral deposits in the Valles Marineris region, and the possible role of saline waters in forming recent geomorphologic features all underscore the need to understand the physical properties of highly concentrated solutions on Mars in addition to, and as a function of, their distinct chemistry. Using thermodynamic models predicting saline mineral solubility, we generate likely brine compositions ranging from bicarbonate-dominated to sulfate-dominated and predict their saline mineralogy. For each brine composition, we then estimate a number of thermal, transport, and colligative properties using established models that have been developed for highly concentrated multicomponent electrolyte solutions. The available experimental data and theoretical models that allow estimation of these physicochemical properties encompass, for the most part, much of the anticipated variation in chemistry for likely Martian brines. These estimates allow significant progress in building a detailed analysis of physical sedimentation at the ancient Martian surface and allow more accurate predictions of thermal behavior and the diffusive transport of matter through chemically distinct solutions under comparatively nonstandard conditions.

  20. Simulated Fizeau ring fringes in transmission through spherical and plane reflected surfaces (United States)

    Ramadan, W. A.; Wahba, H. H.


    In this paper, we present simulated Fizeau ring fringes. These fringes are constructed due to multiple reflection between highly reflected partially transmitted spherical and plane surfaces. The real paths of rays and consequently their amplitudes and phases have been determined when they reached the image plane. This plane is located at a certain distance above the interferometer. In these calculations, the impact of the image plane position, the radius of the spherical surface and the distance between the two surfaces on the fringe intensity distribution are investigated. A quite interesting result of our calculation is that the number of the interfered rays is varied and could be only two, even for a highly reflected surfaces. Three different estimated visualizations are included to give an overview imagination of the impact of the different parameter variation. These could be helpful for researchers for testing of spherical surfaces using interference-based methods.

  1. [Experimental Methods and Result Analysis of a Variety of Spectral Reflectance Properties of the Thin Oil Film]. (United States)

    Ye, Zhou; Liu, Li; Wei, Chuan-xin; Gu, Qun; An, Ping-ao; Zhao, Yue-jiao; Yin, Da-yi


    In order to analysis the oil spill situation based on the obtained data in airborne aerial work, it's needed to get the spectral reflectance characteristics of the oil film of different oils and thickness as support and to select the appropriate operating band. An experiment is set up to measure the reflectance spectroscopy from ultraviolet to near-infrared for the film of five target samples, which means petrol, diesel, lubricating oil, kerosene and fossil, using spectral measurement device. The result is compared with the reflectance spectra of water in the same experimental environment, which shows that the spectral reflection characteristics of the oil film are related to the thickness and the type of the oil film. In case of the same thickness, the spectral reflectance curve of different types of film is far different, and for the same type of film, the spectral reflectance curve changes accordingly with the change of film thickness, therefore in terms of the single film, different film thickness can be distinguished by reflectance curves. It also shows that in terms of the same film thickness, the reflectance of diesel, kerosene, lubricants reaches peak around 380 nm wavelength, obviously different from the reflectance of water, and that the reflectance of crude oil is far less than that of water in more than 340 nm wavelength, and the obtained reflection spectrum can be used to distinguish between different types of oil film to some extent. The experiment covers main types of spilled oil, with data comprehensively covering commonly used detect spectral bands, and quantitative description of the spectral reflectance properties of film. It provides comprehensive theoretical and data support for the selection of airborne oil spill detection working band and the detection and analysis of water-surface oil spill.

  2. Reflection of diffuse light from dielectric one-dimensional rough surfaces. (United States)

    González-Alcalde, Alma K; Méndez, Eugenio R; Terán, Emiliano; Cuppo, Fabio L S; Olivares, J A; García-Valenzuela, Augusto


    We study the reflection of diffuse light from 1D randomly rough dielectric interfaces. Results for the reflectance under diffuse illumination are obtained by rigorous numerical simulations and then contrasted with those obtained for flat surfaces. We also explore the possibility of using perturbation theories and conclude that they are limited for this type of study. Numerical techniques based on Kirchhoff approximation and reduced Rayleigh equations yield better results. We find that, depending on the refractive index contrast and nature of the irregularities, the roughness can increase or decrease the diffuse reflectance of the surface.

  3. NPP/VIIRS Atmospherically Corrected Surface Reflectance 6-Min L2 Swath 375m, 750m NRT (United States)

    National Aeronautics and Space Administration — The VNP09_NRT is a Near Real Time (NRT) S-NPP/VIIRS 375 m, 750 m Atmospherically Corrected Surface Reflectance product. The NPP/VIIRS surface reflectance products...

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

  5. VIIRS/NPP Surface Reflectance Daily L2G Global 1km and 500m SIN Grid V001 (United States)

    National Aeronautics and Space Administration — The Visible Infrared Imaging Radiometer Suite (VIIRS) daily surface reflectance (VNP09GA) Version 1 product provides an estimate of land surface reflectance from the...

  6. Broadband infrared reflective surfaces using doped and stacked polar dielectric layers (United States)

    Janipour, Mohsen; Sendur, Kursat


    Polar dielectrics, such as SiC, are excellent candidates for operation in extreme environments due to their excellent mechanical and thermal properties. In addition, they can achieve good IR reflection in the Reststrahlen band. However, these materials have relatively narrow spectral bandwidth for reflection, especially considering that the broadband illumination sources in extreme environments. In this study, we investigated the broadband reflection properties of polar dielectrics by engineering the Reststrahlen band through doping and stacked layers. Our results indicate that by doping polar dielectrics, spectral reflection bandwidth can be significantly broadened. In addition, we demonstrate that by stacking different polar dielectric layers, the reflection spectrum of different materials can be overlapped, and thereby, significantly broader spectrum is obtained.

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

  8. The sparkle of the eye: the impact of ocular surface wetness on corneal light reflection. (United States)

    Goto, Eiki; Dogru, Murat; Sato, Enrique Adan; Matsumoto, Yukihiro; Takano, Yoji; Tsubota, Kazuo


    To measure the sparkle of the human eye evaluated by the intensity of corneal light reflection in normal subjects and dry eye patients to investigate whether ocular surface wetness has an impact on the sparkle of the eye. Prospective case-control study. We examined a consecutive series of eight dry eye patients with Sjögren syndrome (SS, 15 eyes), as well as eight normal subjects (16 eyes). The specular corneal surface light reflection was quantitatively measured with an ophthalmic slit-lamp microscope and image capturing system under fixed conditions of light source, incident angle, and detector sensitivity. The intensity of images from subjects' corneal light reflection was quantified with image analysis software along with the measurement of grade of self-reported brilliancy of the eye, corneal fluorescein staining score, tear film break-up time, and Schirmer test value. The intensity of corneal light reflection was also compared before and after dry eye treatment. The mean intensity of corneal light reflection was significantly lower in dry eye patients (125.0 ± 40.1) than normal subjects (167.6 ± 36.6, P=.004). Grade of self-reported brilliancy of the eye, corneal fluorescein staining scores, tear film break-up time, and Schirmer test values showed good correlation to the intensity of corneal light reflection. After punctal plug treatment, the intensity of corneal light reflection significantly increased from 125.0 ± 40.1 to 167.2 ± 45.0 (Plight reflection representing the sparkle of the eye was significantly more intense in normal subjects compared to dry eye patients, and was increased after punctal plug treatment. The intensity of corneal light reflection appeared to correlate well with tear film stability, volume, and ocular surface desiccation. We showed that tears contributed not only to ocular surface wetness but also to the extent of the light reflection from the eye. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. 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: [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)


    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.

  10. Reflection of plane waves from free surface of a microstretch elastic ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The problem of reflection of plane waves from free surface of a microstretch elastic solid half-space is studied. The energy ratios for ... axis is taken normal to free surface in downward direction. The region z > 0 is occupied by linear ... Superposed dots on the right hand side of above equations denote the second partial ...

  11. Magnetic properties of Martian surface material (United States)

    Hargraves, R. B.


    The hypothesis that the magnetic properties of the Martian surface material are due to the production of a magnetic phase in the clay mineral nontronite by transient shock heating is examined. In the course of the investigation a magnetic material is produced with rather unusual properties. Heating from 900 C to 1000 C, of natural samples of nontronite leads first to the production of what appears to be Si doped maghemite gamma (-Fe2O3). Although apparently metastable, the growth of gamma -Fe2O3 at these temprtures is unexpected, and its relative persistence of several hours at 1000 C is most surprising. Continued annealing of this material for longer periods promote the crystallization of alpha Fe2O3 and cristobalite (high temperature polymorph of SiO2). All available data correlate this new magnetic material with the cristobalite hence our naming it magnetic ferri cristobalite. Formation of this magnetic cristobalite, however, may require topotactic growth from a smectite precursor.

  12. Temperature comparison of different reflective surfaces of a solar thermal collector (United States)

    Koh, Yit Yan; Chua, Yaw Long; Chin, Kiat Keong


    With the rapid depletion of fossil fuels, the search for application of alternative energy sources becomes more important than ever before. Solar energy has been identified as one of the major renewable energy that will contribute to power generation is years to come. There are two major categories of solar energy applications. Solar thermal collector is one of it. This paper presents an investigation on the effect of different reflecting surfaces on solar thermal collector. Three different reflective surfaces were applied on the surface of the solar thermal collector. Data was collected and analyzed. From the results, the aluminum mirror sheet performed best.

  13. Reflections

    Directory of Open Access Journals (Sweden)

    Joanne Embree


    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.

  14. A high-reflective surface measurement method based on conoscopic holography technology (United States)

    Cheng, Xu; Li, ZhongWei; Shi, YuSheng; Zhao, HengShuang; Zhan, Guomin


    Measuring high-reflective surfaces using optical method is always a big challenging problem. This paper presents a high-reflective surface measurement method based on conoscopic holography technology using a 4D motion platform equipped with a conoscopic holography optical probe. There are two key problems needed to solve before the automate scan of the complex shape surface: the coordinate calibration and the path planning. To improve the calibration efficiency and accuracy, the coordinate calibration is divided into two parts: the rough calibration and the accurate registration. The path planning consists of two aspects including: the path points generation and the path points verification. In addition, by scanning the objects having high-reflective surfaces, such as the metal blades, coins and other work-pieces, the efficiency of the measurement method has been verified.

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

    Directory of Open Access Journals (Sweden)

    E. Aas


    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.

  16. Influence of aerosol and surface reflectance variability on hyperspectral observed radiance

    Directory of Open Access Journals (Sweden)

    C. Bassani


    Full Text Available Current aerosol retrievals based on visible and near infrared remote-sensing, are prone to loss of accuracy, where the assumptions of the applied algorithm are violated. This happens mostly over land and it is related to misrepresentation of specific aerosol conditions or surface properties. New satellite missions, based on high spectral resolution instruments, such as PRISMA (Hyperspectral Precursor of the Application Mission, represent a valuable opportunity to improve the accuracy of τa550 retrievable from a remote-sensing system developing new atmospheric measurement techniques. This paper aims to address the potential of these new observing systems in more accurate retrieving τa550, specifically over land in heterogeneous and/or homogeneous areas composed by dark and bright targets. The study shows how the variation of the hyperspectral observed radiance can be addressed to recognise a variation of Δτa550 = 0.02. The goal has been achieved by using simulated radiances by combining two aerosol models (urban and continental and two reflecting surfaces: dark (represented by water and bright (represented by sand for the PRISMA instrument, considering the environmental contribution of the observed radiance, i.e., the adjacency effect. Results showed that, in the continental regime, the expected instrument sensitivity would allow for retrieval accuracy of the aerosol optical thickness at 550 nm of 0.02 or better, with a dark surface surrounded by dark areas. The study also showed that for the urban regime, the surface plays a more significant role, with a bright surface surrounded by dark areas providing favourable conditions for the aerosol load retrievals, and dark surfaces representing less suitable situations for inversion independently of the surroundings. However, over all, the results obtained provide evidence that high resolution observations of Earth spectrum between

  17. Suppressing light reflection from polycrystalline silicon thin films through surface texturing and silver nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Akhter, Perveen [Department of Physics, University at Albany-SUNY, Albany, New York 12222 (United States); Huang, Mengbing, E-mail:; Kadakia, Nirag; Spratt, William; Malladi, Girish; Bakhru, Hassarum [SUNY College of Nanoscale Science and Engineering, Albany, New York 12203 (United States)


    This work demonstrates a novel method combining ion implantation and silver nanostructures for suppressing light reflection from polycrystalline silicon thin films. Samples were implanted with 20-keV hydrogen ions to a dose of 10¹⁷/cm², and some of them received an additional argon ion implant to a dose of 5×10¹⁵ /cm² at an energy between 30 and 300 keV. Compared to the case with a single H implant, the processing involved both H and Ar implants and post-implantation annealing has created a much higher degree of surface texturing, leading to a more dramatic reduction of light reflection from polycrystalline Si films over a broadband range between 300 and 1200 nm, e.g., optical reflection from the air/Si interface in the AM1.5 sunlight condition decreasing from ~30% with an untextured surface to below 5% for a highly textured surface after post-implantation annealing at 1000°C. Formation of Ag nanostructures on these ion beam processed surfaces further reduces light reflection, and surface texturing is expected to have the benefit of diminishing light absorption losses within large-size (>100 nm) Ag nanoparticles, yielding an increased light trapping efficiency within Si as opposed to the case with Ag nanostructures on a smooth surface. A discussion of the effects of surface textures and Ag nanoparticles on light trapping within Si thin films is also presented with the aid of computer simulations.

  18. Microwave reflection measurements of the dielectric properties of concrete : final report. (United States)


    The use of microwave reflection measurements to continuously and nondestructively monitor the hydration of concrete is described. The method relies upon the influence of the free-water content on the dielectric properties of the concrete. Use of the ...

  19. Methods of creating solar-reflective nonwhite surfaces and their application to residential roofing materials

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Berdahl, Paul; Akbari, Hashem [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Miller, William [Oak Ridge National Laboratory, PO Box 2008, MS6070, Oak Ridge, TN 37831 (United States); Joedicke, Ingo [ISP Mineral Products, Inc., 34 Charles St., Hagerstown, MD 21740 (United States); Reilly, Joseph [American Rooftile Coatings, 250 Viking Avenue, Brea, CA 92821 (United States); Suzuki, Yoshi [MCA Clay Tile, 1985 Sampson Avenue, Corona, CA 92879 (United States); Vondran, Michelle [Steelscape Inc., 1200 Arrow Route, Rancho Cucamonga, CA 91730 (United States)


    We describe methods for creating solar-reflective nonwhite surfaces and their application to a wide variety of residential roofing materials, including metal, clay tile, concrete tile, wood, and asphalt shingle. Reflectance in the near-infrared (NIR) spectrum (0.7-2.5{mu}m) is maximized by coloring a topcoat with pigments that weakly absorb and (optionally) strongly backscatter NIR radiation, and by adding an NIR-reflective basecoat (e.g., one colored with titanium dioxide rutile white) if both the topcoat and the substrate weakly reflect NIR radiation. Coated steel and glazed clay-tile roofing products achieved NIR reflectances of up to 0.50 and 0.75, respectively, using only cool topcoats. Gray-cement concrete tiles achieved NIR reflectances as high as 0.60 with coatings colored by NIR-scattering pigments. Such tiles could attain NIR reflectances of up to 0.85 by overlaying a white basecoat with a topcoat colored by NIR-transparent organic pigments. Granule-surfaced asphalt shingles achieved NIR reflectances as high as 0.45 when the granules were covered with a white basecoat and a cool color topcoat. (author)

  20. Sensitivity analysis of 6S-based look-up table for surface reflectance retrieval (United States)

    Lee, Chang Suk; Yeom, Jong Min; Lee, Han Lim; Kim, Jae-Jin; Han, Kyung-Soo


    We created a look-up table (LUT) based on the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) radiative transfer model, which reduces large errors in the surface reflectance retrieval under high solar zenith angle (SZA) conditions. The LUT was calculated in 10° SZA intervals containing pre-computed atmospheric correction coefficients as a function of discretized pre-defined input parameters. In order to validate the performance of the LUT, we compared the retrieved surface reflectance using the LUT against a retrieval performed using the simplified method of atmospheric correction (SMAC). These results were validated against MODIS reflectance data (MOD09). The surface reflectance obtained using the LUT was highly correlated with the MOD09, with a coefficient of determination (R2) of 0.88 (red band) and 0.94 (NIR). The retrieved surface reflectance had a root mean-squared error of 0.0132 (red band) and 0.0191 (NIR). Accuracy of surface reflectance retrieved using our LUT with a 10° SZA interval was better than that of the obtained using SMAC. However, certain errors were still present particularly at high SZAs. In order to increase the accuracy at high SZAs, new LUT was computed with a finer SZA interval (5°) at high SZAs. In both red and NIR bands, the R2, fine SZA interval LUT (0.92) were compared to the coarse SZA interval LUT (0.74) of around 65°. Additionally, the run time for surface reflectance retrievals with our LUT was almost comparable to that of the SMAC, an operational model. This study demonstrates that proper SZAs interval for making LUT in high SZA range.

  1. Iterative discrete ordinates solution of the equation for surface-reflected radiance (United States)

    Radkevich, Alexander


    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. Spectral and spatial properties of polarized light reflections from the arms of squid (Loligo pealeii) and cuttlefish (Sepia officinalis L.). (United States)

    Chiou, Tsyr-Huei; Mäthger, Lydia M; Hanlon, Roger T; Cronin, Thomas W


    On every arm of cuttlefish and squid there is a stripe of high-reflectance iridophores that reflects highly polarized light. Since cephalopods possess polarization vision, it has been hypothesized that these polarized stripes could serve an intraspecific communication function. We determined how polarization changes when these boneless arms move. By measuring the spectral and polarizing properties of the reflected light from samples at various angles of tilt and rotation, we found that the actual posture of the arm has little or no effect on partial polarization or the e-vector angle of the reflected light. However, when the illumination angle changed, the partial polarization of the reflected light also changed. The spectral reflections of the signals were also affected by the angle of illumination but not by the orientation of the sample. Electron microscope samples showed that these stripes are composed of several groups of multilayer platelets within the iridophores. The surface normal to each group is oriented at a different angle, which produces essentially constant reflection of polarized light over a range of viewing angles. These results demonstrate that cuttlefish and squid could send out reliable polarization signals to a receiver regardless of arm orientation.

  3. Investigation of surface and sub-surface damage in high quality synthetic diamonds by X-ray reflectivity and grazing incidence in-plane diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Bussone, Genziana; Lafford, Tamzin A.; Masiello, Fabio; Carbone, Gerardina; Schuelli, Tobias U.; Rommeveaux, Amparo Vivo; Haertwig, Juergen [European Synchrotron Radiation Facility, 6, Rue Jules Horowitz, BP 220, 38043 Grenoble Cedex 9 (France); Gibaud, Alain [Laboratoire PEC, Universite du Maine le Mans, Avenue Olivier Messiaen, 72 085 Le Mans (France); Connell, Simon H. [University of Johannesburg, cnr Kingsway Ave and University Rd, Auckland Park, 2006, Johannesburg (South Africa); Wormington, Matthew [Jordan Valley Semiconductors Inc., 8601 Cross Park Drive, Suite 200, Austin, TX 78754-4578 (United States)


    High quality single-crystal synthetic diamond is the most suitable material for selected X-ray optical applications in the latest generation X-ray light sources. Excellent heat handling properties, as well as low absorption, coupled with high perfection in the crystal bulk and very good surface quality, are crucial for such applications. In recent years, some progress has been made in the fields of surface treatments and growth techniques. Conventional scaife polishing is largely ineffective on the diamond (111) surface. To overcome this disadvantage, one possibility is to use the Hot Metal polishing technique. An investigation of surface and sub-surface damage of Hot Metal polished and cleaved surfaces, has been carried out using depth-sensitive non-destructive X-ray techniques. The near surface crystalline quality was studied as a function of depth using in-plane grazing incidence X-ray diffraction. Additionally, X-ray reflectivity was used to investigate the density, thickness and roughness of near-surface layers. The measurements enable us to estimate the thickness of the affected sub-surface layer. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Probing Anisotropic Surface Properties and Surface Forces of Fluorite Crystals. (United States)

    Gao, Zhiyong; Xie, Lei; Cui, Xin; Hu, Yuehua; Sun, Wei; Zeng, Hongbo


    Fluorite is the most important mineral source for producing fluorine-based chemicals and materials in a wide range of engineering and technological applications. In this work, atomic force microscopy was employed, for the first time, to probe the surface interactions and adhesion energy of model oleic acid (a commonly used surface modification organics for fluorite) molecules on fluorite surfaces with different orientations in both air and aqueous solutions at different pH conditions. Fitted with the Derjaguin-Landau-Verwey-Overbeek theory, the force results during surface approaching demonstrate the anisotropy in the surface charge of different orientations, with the {111} surface exhibiting a higher magnitude of surface charge, which could be attributed to the difference in the atomic composition. The adhesion measured during surface retraction shows that model oleic acid molecules have a stronger adhesion with the {100} surface than with the {111} surface in both air and aqueous solutions. The anisotropic adhesion energy was analyzed in relation to the surface atom (especially calcium) activity, which was supported by the surface free energy results calculated based on a three-probe-liquid method. Each calcium atom on the {100} surface with four dangling bonds is more active than the calcium atom on the {111} surface with only one dangling bond, supported by a larger value of the Lewis acid component for the {100} surface. The model oleic acid molecules present in the ionic form at pH 9 exhibit a higher adhesion energy with fluorite surfaces as compared to their molecular form at pH 6, which was related to the surface activity of different forms. The adhesion energy measured in solution is much lower than that in air, indicating that the solvent exerts an important influence on the interactions of organic molecules with mineral surfaces. The results provide useful information on the fundamental understanding of surface interactions and adhesion energy of organic

  5. Determining Surface Material Properties Using Satellite Imaging (United States)

    Gloudeman, C.; Gerace, A. D.


    Knowledge of soil moisture content is necessary for drought monitoring, crop irrigation, and water runoff. Remote sensing techniques provide a more efficient alternative to traditional field measurements for determining soil moisture content. Thermal infrared sensors from Landsat, MODIS Aqua & Terra, and AVHRR MetOp A & B satellites were used to find thermal inertia, which is highly correlated with soil moisture. A diurnal cycle is converted from band effective radiance to Land Surface Temperature (LST) using Planck's Law for blackbody radiation and a modified split-window algorithm. The THERM model for finding expected LST is then used to determine the material properties. A second approach was used to calculate apparent thermal inertia and soil moisture content from day/ night pairs of LST. For this method, only the MODIS Aqua LST product was used.To this end, we have observed clear differences in moisture between areas of vegetation and sand and between different crop fields. Our results indicate that matching the observed data with the THERM model could be improved with increased satellite measurements.

  6. Determining the properties of dense matter: Superconductivity, bulk viscosity, and light reflection in compact stars (United States)

    Good, Gerald J.

    In this dissertation, we investigate the properties of matter, denser than nuclei, that exists inside compact stars. First, we examine a mixed superfluid/superconductor system, which likely occurs in neutron star cores. We derive an effective theory of Cooper pair quasiparticles from a microscopic theory of nucleons, and calculate the coupling strengths between quasiparticles. We then calculate the structure of magnetic flux tubes, taking into consideration interactions between neutron and proton Cooper pairs. We find that interactions between the condensates can lead to interesting phenomena and new phases at the border between type-I and type-II behavior. Next, we examine the response of nuclear matter to vibrational modes by calculating the bulk viscosity from purely leptonic processes. We find that for hot neutron stars, the bulk viscosity due to leptons is very small compared to the bulk viscosity due to nucleons, but for cold neutron stars, the leptonic component is dominant. Finally, we derive the reflection and transmission properties of light at boundaries between phases of matter that have two independent U(1) generators, which may exist at the surface of "strange stars" or at boundaries between different phases of matter in a neutron star.

  7. Application of the complex cepstrum to the location of acoustic sources near reflective surfaces (United States)

    Fuller, C. R.; Tavakkoli, S.; Elliott, K. B.; Hurst, C. J.; Obrien, W. F.


    The complex cepstrum is used to correct bearing estimations of acoustic sources in the presence of a reflective surface. An automated liftering procedure is used which zeros out a block portion of the cepstrum including the echo information. The problem of the resulting distortion is alleviated by applying a coherence criterion to the recovered direct signals at each microphone. Thus to a large degree the interactive nature of cepstral processing is overcome for this application. For the test signals and geometries considered the cepstrum is shown to accurately correct for bearing errors in acoustic signals contaminated with reflections from nearby surfaces.

  8. 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


    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)

  9. Effect of sol aging time on the anti-reflective properties of silica coatings templated with phosphoric acid

    Directory of Open Access Journals (Sweden)

    Wen Wen

    Full Text Available Silica anti-reflective coatings have been prepared by a sol–gel dip-coating process using the sol containing phosphoric acid as a pore-forming template. The effect of the aging time of the sol on the anti-reflective properties has been investigated. The surface topography of the silica AR coatings has been characterized. With increasing sol aging time, more over-sized pores larger than 100 nm are formed in the silica coatings. These could act as scattering centers, scattering visible light and thereby lowering transmittance. The optimal aging time was identified as 1 day, and the corresponding silica coatings showed a maximum transmittance of 99.2%, representing an 8% increase compared to the bare glass substrate. Keywords: Thin films, Anti-reflective coatings, Aging, Dip-coating, Sol–gel preparation

  10. Numerical study of three-dimensional sound reflection from corrugated surface waves. (United States)

    Choo, Youngmin; Song, H C; Seong, Woojae


    When a sound wave propagates in a water medium bounded by a smooth surface wave, reflection from a wave crest can lead to focusing and result in rapid variation of the received waveform as the surface wave moves [Tindle, Deane, and Preisig, J. Acoust. Soc. Am. 125, 66-72 (2009)]. In prior work, propagation paths have been constrained to be in a plane parallel to the direction of corrugated surface waves, i.e., a two-dimensional (2-D) propagation problem. In this paper, the azimuthal dependence of sound propagation as a three-dimensional (3-D) problem is investigated using an efficient, time-domain Helmholtz-Kirchhoff integral formulation. When the source and receiver are in the plane orthogonal to the surface wave direction, the surface wave curvature vanishes in conventional 2-D treatments and the flat surface simply moves up and down, resulting in minimal temporal variation of the reflected signal intensity. On the other hand, the 3-D propagation analysis reveals that a focusing phenomenon occurs in the reflected signal due to the surface wave curvature formed along the orthogonal plane, i.e., out-of-plane scattering.

  11. Early Evaluation of the VIIRS Calibration, Cloud Mask and Surface Reflectance Earth Data Records (United States)

    Vermote, Eric; Justice, Chris; Csiszar, Ivan


    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.

  12. In situ probing of surface hydrides on hydrogenated amorphous silicon using attenuated total reflection infrared spectroscopy

    CERN Document Server

    Kessels, W M M; Sanden, M C M; Aydil, E S


    An in situ method based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is presented for detecting surface silicon hydrides on plasma deposited hydrogenated amorphous silicon (a-Si:H) films and for determining their surface concentrations. Surface silicon hydrides are desorbed by exposing the a-Si:H films to low energy ions from a low density Ar plasma and by comparing the infrared spectrum before and after this low energy ion bombardment, the absorptions by surface hydrides can sensitively be separated from absorptions by bulk hydrides incorporated into the film. An experimental comparison with other methods that utilize isotope exchange of the surface hydrogen with deuterium showed good agreement and the advantages and disadvantages of the different methods are discussed. Furthermore, the determination of the composition of the surface hydrogen bondings on the basis of the literature data on hydrogenated crystalline silicon surfaces is presented, and quantification of the h...

  13. 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


    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

  14. Negligible water surface charge determined using Kelvin probe and total reflection X-ray fluorescence techniques. (United States)

    Shapovalov, Vladimir L; Möhwald, Helmuth; Konovalov, Oleg V; Knecht, Volker


    The water surface charge has been extensively debated in recent decades. Electrophoretic mobilities of air bubbles in water and disjoining pressures between the surfaces of aqueous films suggest that the surface of water exhibits a significant negative charge. This is commonly attributed to a strong adsorption of hydroxide ions at the interface, though spectroscopic measurements and simulation studies suggest surface depletion of hydroxide ions. Alternatively, the negative surface charge could arise from surface contamination with trace charged surfactants. We have probed the variation in the surface charge of water with pH by measuring surface potentials using the Kelvin probe technique. Independently, the abundance in the interfacial layer of "reporter ions" (Rb(+) and Br(-)), which must be affected by a charged surface, has been monitored using the total reflection X-ray fluorescence (TRXF) technique. Special care was taken to prove the high sensitivity of this technique as well as to avoid surface contaminants. The magnitude of the surface charge was found to be below 1 e per 500 nm(2) (TRXF). No evidence of variations in the surface potential between pH 2-3 and pH 9-12 was detected within the accuracies of the methods (5 mV for Kelvin probe and 2 mV for TRXF). Hence, our findings suggest that the clean water surface exhibits negligible charge in a wide pH range.

  15. Development of Surfaces Optically Suitable for Flat Solar Panels. [using a reflectometer which separately evaluates spectral and diffuse reflectivities of surfaces (United States)


    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.

  16. The Effects of Surface Roughness on the Apparent Thermal and Optical Properties of the Moon (United States)

    Rubanenko, L.; Hayne, P. O.; Paige, D. A.


    The thermal inertia and albedo of airless planetary bodies such as the Moon can be inferred by measuring the surface temperatures and solar reflectance. However, roughness below the instrument resolution can affect these measured parameters. Scattering and IR emission from warm slopes onto colder slopes change the surface cooling rate, while shadowing and directional scattering change the reflectance. The importance of these effects grows with increasing solar incidence and emission angles, and during solar eclipses during which the insolation decreases rapidly. The high-quality data gathered by the Lunar Reconnaissance Orbiter (LRO) mission during the last seven years provides us with a unique opportunity to study these effects. Previous works have either adopted a simplified roughness model composed of a single slope, or an illumination model that does not account for subsurface conduction. Our approach incorporates data with simulations conducted using a coupled thermal and illumination model. First, we model the surface temperature distribution below the instrument resolution, considering two realizations: a cratered surface and a Gaussian random surface. Then, we fit the rough surface brightness temperature distribution to that of a flat surface with effective thermal and optical properties to find they differ from the original properties by up to 20% due to the added surface roughness. In the future, this will help to better constrain the intrinsic physical properties of the surface on both the Moon and Mercury and also other airless bodies such as asteroids.

  17. Retrieval of tropospheric aerosol properties over land from visible and near-infrared spectral reflectance: Application over Maryland (United States)

    Levy, Robert Carroll

    Aerosols are major components of the Earth's global climate system, affecting the radiation budget and cloud processes of the atmosphere. When located near the surface, high concentrations lead to lowered visibility, increased health problems and generally reduced quality of life for the human population. Over the United States mid-Atlantic region, aerosol pollution is a problem mainly during the summer. Satellites, such as the MODerate Imaging Spectrometer (MODIS), from their vantage point above the atmosphere, provide unprecedented coverage of global and regional aerosols over land. During MODIS' eight-year operation, exhaustive data validation and analyses have shown how the algorithm should be improved. This dissertation describes the development of the 'second-generation' operational algorithm for retrieval of global tropospheric aerosol properties over dark land surfaces, from MODIS-observed spectral reflectance. New understanding about global aerosol properties, land surface reflectance characteristics, and radiative transfer properties were learned in the process. This new operational algorithm performs a simultaneous inversion of reflectance in two visible channels (0.47 and 0.66 mum) and one shortwave infrared channel (2.12 mum), thereby having increased sensitivity to coarse aerosol. Inversion of the three channels retrieves the aerosol optical depth (tau) at 0.55 mum, the percentage of non-dust (fine model) aerosol (eta) and the surface reflectance. This algorithm is applied globally, and retrieves tau that is highly correlated (y = 0.02 + 1.0x, R=0.9) with ground-based sunphotometer measurements. The new algorithm estimates the global, over-land, long-term averaged tau ˜ 0.21, a 25% reduction from previous MODIS estimates. This leads to reducing estimates of global, non-desert, over-land aerosol direct radiative effect (all aerosols) by 1.7 W·m-2 (0.5 W·m-2 over the entire globe), which significantly impacts assessment of aerosol direct radiative

  18. Surface elastic properties in silicon nanoparticles (United States)

    Melis, Claudio; Giordano, Stefano; Colombo, Luciano


    The elastic behavior of the external surface of a solid body plays a key role in nanomechanical phenomena. While bulk elasticity enjoys the benefits of a robust theoretical understanding, many surface elasticity features remain unexplored: some of them are here addressed by blending together continuum elasticity and atomistic simulations. A suitable readdressing of the surface elasticity theory allows to write the balance equations in arbitrary curvilinear coordinates and to investigate the dependence of the surface elastic parameters on the mean and Gaussian curvatures of the surface. In particular, we predict the radial strain induced by surface effects in spherical and cylindrical silicon nanoparticles and provide evidence that the surface parameters are nearly independent of curvatures and, therefore, of the surface conformation.

  19. High-resolution x-ray scatter and reflectivity study of sputtered IR surfaces

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Abdali, S.; Hornstrup, Allan


    In recent years there has been an increased interest in the possible use of Ir as the reflecting surface in X-ray telescope programs. An X-ray study of such surfaces produced by sputtering of Ir on highly polished Zerodur flats is presented here. The study was performed using Fe K(alpha) 1 (6...... result shows that an Ir coating can be produced with nominal bulk density....

  20. Impact of MODIS Sensor Calibration Updates on Greenland Ice Sheet Surface Reflectance and Albedo Trends (United States)

    Casey, Kimberly A.; Polashenski, Chris M.; Chen, Justin; Tedesco, Marco


    We evaluate Greenland Ice Sheet (GrIS) surface reflectance and albedo trends using the newly released Collection 6 (C6) MODIS (Moderate Resolution Imaging Spectroradiometer) products over the period 2001-2016. We find that the correction of MODIS sensor degradation provided in the new C6 data products reduces the magnitude of the surface reflectance and albedo decline trends obtained from previous MODIS data (i.e., Collection 5, C5). Collection 5 and 6 data product analysis over GrIS is characterized by surface (i.e., wet vs. dry) and elevation (i.e., 500-2000 m, 2000 m and greater) conditions over the summer season from 1 June to 31 August. Notably, the visible-wavelength declining reflectance trends identified in several bands of MODIS C5 data from previous studies are only slightly detected at reduced magnitude in the C6 versions over the dry snow area. Declining albedo in the wet snow and ice area remains over the MODIS record in the C6 product, albeit at a lower magnitude than obtained using C5 data. Further analyses of C6 spectral reflectance trends show both reflectance increases and decreases in select bands and regions, suggesting that several competing processes are contributing to Greenland Ice Sheet albedo change. Investigators using MODIS data for other ocean, atmosphere and/or land analyses are urged to consider similar re-examinations of trends previously established using C5 data.

  1. Impact of MODIS sensor calibration updates on Greenland Ice Sheet surface reflectance and albedo trends (United States)

    Casey, Kimberly A.; Polashenski, Chris M.; Chen, Justin; Tedesco, Marco


    We evaluate Greenland Ice Sheet (GrIS) surface reflectance and albedo trends using the newly released Collection 6 (C6) MODIS (Moderate Resolution Imaging Spectroradiometer) products over the period 2001-2016. We find that the correction of MODIS sensor degradation provided in the new C6 data products reduces the magnitude of the surface reflectance and albedo decline trends obtained from previous MODIS data (i.e., Collection 5, C5). Collection 5 and 6 data product analysis over GrIS is characterized by surface (i.e., wet vs. dry) and elevation (i.e., 500-2000 m, 2000 m and greater) conditions over the summer season from 1 June to 31 August. Notably, the visible-wavelength declining reflectance trends identified in several bands of MODIS C5 data from previous studies are only slightly detected at reduced magnitude in the C6 versions over the dry snow area. Declining albedo in the wet snow and ice area remains over the MODIS record in the C6 product, albeit at a lower magnitude than obtained using C5 data. Further analyses of C6 spectral reflectance trends show both reflectance increases and decreases in select bands and regions, suggesting that several competing processes are contributing to Greenland Ice Sheet albedo change. Investigators using MODIS data for other ocean, atmosphere and/or land analyses are urged to consider similar re-examinations of trends previously established using C5 data.

  2. Impact of MODIS sensor calibration updates on Greenland Ice Sheet surface reflectance and albedo trends

    Directory of Open Access Journals (Sweden)

    K. A. Casey


    Full Text Available We evaluate Greenland Ice Sheet (GrIS surface reflectance and albedo trends using the newly released Collection 6 (C6 MODIS (Moderate Resolution Imaging Spectroradiometer products over the period 2001–2016. We find that the correction of MODIS sensor degradation provided in the new C6 data products reduces the magnitude of the surface reflectance and albedo decline trends obtained from previous MODIS data (i.e., Collection 5, C5. Collection 5 and 6 data product analysis over GrIS is characterized by surface (i.e., wet vs. dry and elevation (i.e., 500–2000 m, 2000 m and greater conditions over the summer season from 1 June to 31 August. Notably, the visible-wavelength declining reflectance trends identified in several bands of MODIS C5 data from previous studies are only slightly detected at reduced magnitude in the C6 versions over the dry snow area. Declining albedo in the wet snow and ice area remains over the MODIS record in the C6 product, albeit at a lower magnitude than obtained using C5 data. Further analyses of C6 spectral reflectance trends show both reflectance increases and decreases in select bands and regions, suggesting that several competing processes are contributing to Greenland Ice Sheet albedo change. Investigators using MODIS data for other ocean, atmosphere and/or land analyses are urged to consider similar re-examinations of trends previously established using C5 data.

  3. 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

    a monoclinic elastic half-space. Numerical results presented indicate that the anisotropy might affect the reflection coefficients significantly. 2. Basic equations. Consider a homogeneous anisotropic elastic medium of monoclinic type. It has one plane of elastic symmetry and its elastic properties are defined by thirteen elastic ...

  4. 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)


    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.

  5. In Situ Nondestructive Analysis of Kalanchoe pinnata Leaf Surface Structure by Polarization-Modulation Infrared Reflection-Absorption Spectroscopy. (United States)

    Hama, Tetsuya; Kouchi, Akira; Watanabe, Naoki; Enami, Shinichi; Shimoaka, Takafumi; Hasegawa, Takeshi


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

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

  8. Introducing a mini-catamaran to perform reflectance measurements above and below the water surface (United States)

    Froidefond, Jean-Marie; Ouillon, Sylvain


    An innovative platform is tested to perform reflectance measurements at sea. This platform is a mini-catamaran with two hulls 1m long and set 0.7m apart, fitted with optical sensors. It can be used far away from an oceanographic ship to avoid its hull influencing the measurement. Reflectance measurements were performed with a TriOS radiance sensor placed +2cm or -2cm from the water surface and a TriOS irradiance sensor. Tests were carried out in calm seas and with cloud cover. The processing to derive marine radiances from raw measurements is detailed. When the radiance sensor is above the interface, it limits the sky reflections on the targeted surface and the radiance is identical to that deduced from measurements below the surface. When the sensor is placed at +3cm abovewater or higher, glint affects the measurements. The mini-catamaran shows a good ability to measure marine reflectance with an adapted measurement protocol. Except for very turbid waters, it seems preferable to perform upwelling radiance measurements below the surface.

  9. Total reflection PIXE (TPIXE) and RBS for surface and trace element analysis.

    NARCIS (Netherlands)

    van Kan, J.A.; Vis, R.D.


    MeV proton and α beams at small incident angles (0-35 mrad) were used to analyse flat surfaces such as Si wafers and coated quartz substrates. X-rays and backscattered particles were detected in a total reflection geometry. Using TPIXE a quick and simultaneous detection of different trace elements

  10. One-step Maskless Fabrication and Optical Characterization of Silicon Surfaces with Antireflective Properties and a White Color Appearance

    DEFF Research Database (Denmark)

    Sun, Ling; Feidenhans'l, Nikolaj Agentoft; Telecka, Agnieszka


    We report a simple one-step maskless fabrication of inverted pyramids on silicon wafers by reactive ion etching. The fabricated surface structures exhibit excellent anti-reflective properties: The total reflectance of the nano inverted pyramids fabricated by our method can be as low as 12% without...

  11. 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


    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 BRDF-adjusted 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...

  12. Suppressing light reflection from polycrystalline silicon thin films through surface texturing and silver nanostructures

    International Nuclear Information System (INIS)

    Akhter, Perveen; Huang, Mengbing; Kadakia, Nirag; Spratt, William; Malladi, Girish; Bakhru, Hassarum


    This work demonstrates a novel method combining ion implantation and silver nanostructures for suppressing light reflection from polycrystalline silicon thin films. Samples were implanted with 20-keV hydrogen ions to a dose of 10 17 /cm 2 , and some of them received an additional argon ion implant to a dose of 5 × 10 15 /cm 2 at an energy between 30 and 300 keV. Compared to the case with a single H implant, the processing involved both H and Ar implants and post-implantation annealing has created a much higher degree of surface texturing, leading to a more dramatic reduction of light reflection from polycrystalline Si films over a broadband range between 300 and 1200 nm, e.g., optical reflection from the air/Si interface in the AM1.5 sunlight condition decreasing from ∼30% with an untextured surface to below 5% for a highly textured surface after post-implantation annealing at 1000 °C. Formation of Ag nanostructures on these ion beam processed surfaces further reduces light reflection, and surface texturing is expected to have the benefit of diminishing light absorption losses within large-size (>100 nm) Ag nanoparticles, yielding an increased light trapping efficiency within Si as opposed to the case with Ag nanostructures on a smooth surface. A discussion of the effects of surface textures and Ag nanoparticles on light trapping within Si thin films is also presented with the aid of computer simulations.

  13. Methods of Creating Solar-Reflective Nonwhite Surfaces and theirApplication to Residential Roofing Materials

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Berdahl, Paul; Akbari, Hashem; Miller, William; Joedicke, Ingo; Reilly, Joseph; Suzuki, Yoshi; Vondran, Michelle


    We describe methods for creating solar-reflective nonwhitesurfaces and their application to a wide variety of residential roofingmaterials, including metal, clay tile, concrete tile, wood, and asphaltshingle. Reflectance in the near-infrared (NIR) spectrum (0.7 2.5mu m) ismaximized by coloring a topcoatwith pigments that weakly absorb and(optionally) strongly backscatter NIR radiation, and adding anNIR-reflective basecoat (e.g., titanium dioxide white) if both thetopcoat and substrate weakly reflect NIR radiation. Coated steel andglazed clay tile roofing products achieved NIRreflectances of up to 0.50and 0.75, respectively, using only cool topcoats. Gray concrete tilesachieve NIR reflectances as high as 0.60 when thickly coated withNIR-scattering pigments, and could attain an NIR reflectances as high as0.85 by overlaying a titanium-dioxide basecoat with a topcoat colored byNIR-transparent organic pigments. Granule-surfaced asphalt shinglesachieved NIR reflectances as high as 0.45 when a cool color topcoat wasapplied over a thick white basecoat.

  14. Effects of atomic oxygen irradiation on the surface properties of phenolphthalein poly(ether sulfone)

    International Nuclear Information System (INIS)

    Pei Xianqiang; Li Yan; Wang Qihua; Sun Xiaojun


    To study the effects of low earth orbit environment on the surface properties of polymers, phenolphthalein poly(ether sulfone) (PES-C) blocks were irradiated by atomic oxygen in a ground-based simulation system. The surface properties of the pristine and irradiated blocks were studied by attenuated total-reflection FTIR (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM). It was found that atomic oxygen irradiation induced the destruction of PES-C molecular chains, including the scission and oxidation of PES-C molecular chains, as evidenced by FTIR and XPS results. The scission of PES-C molecular chains decreased the relative concentration of C in the surface, while the oxidation increased the relative concentration of O in the surface. The changes in surface chemical structure and composition also changed the surface morphology of the block, which shifted from smooth structure before irradiation to 'carpet-like' structure after irradiation

  15. Effects of atomic oxygen irradiation on the surface properties of phenolphthalein poly(ether sulfone)

    Energy Technology Data Exchange (ETDEWEB)

    Pei Xianqiang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No. 18, Tianshui Middle Road, Lanzhou 730000 (China); Li Yan [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No. 18, Tianshui Middle Road, Lanzhou 730000 (China); Graduate school of the Chinese Academy of Sciences, Beijing 100039 (China); Wang Qihua [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No. 18, Tianshui Middle Road, Lanzhou 730000 (China)], E-mail:; Sun Xiaojun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, No. 18, Tianshui Middle Road, Lanzhou 730000 (China)


    To study the effects of low earth orbit environment on the surface properties of polymers, phenolphthalein poly(ether sulfone) (PES-C) blocks were irradiated by atomic oxygen in a ground-based simulation system. The surface properties of the pristine and irradiated blocks were studied by attenuated total-reflection FTIR (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM). It was found that atomic oxygen irradiation induced the destruction of PES-C molecular chains, including the scission and oxidation of PES-C molecular chains, as evidenced by FTIR and XPS results. The scission of PES-C molecular chains decreased the relative concentration of C in the surface, while the oxidation increased the relative concentration of O in the surface. The changes in surface chemical structure and composition also changed the surface morphology of the block, which shifted from smooth structure before irradiation to 'carpet-like' structure after irradiation.

  16. Effects of atomic oxygen irradiation on the surface properties of phenolphthalein poly(ether sulfone) (United States)

    Pei, Xianqiang; Li, Yan; Wang, Qihua; Sun, Xiaojun


    To study the effects of low earth orbit environment on the surface properties of polymers, phenolphthalein poly(ether sulfone) (PES-C) blocks were irradiated by atomic oxygen in a ground-based simulation system. The surface properties of the pristine and irradiated blocks were studied by attenuated total-reflection FTIR (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM). It was found that atomic oxygen irradiation induced the destruction of PES-C molecular chains, including the scission and oxidation of PES-C molecular chains, as evidenced by FTIR and XPS results. The scission of PES-C molecular chains decreased the relative concentration of C in the surface, while the oxidation increased the relative concentration of O in the surface. The changes in surface chemical structure and composition also changed the surface morphology of the block, which shifted from smooth structure before irradiation to "carpet-like" structure after irradiation.

  17. 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.


    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Cuevas, Mauro, E-mail: [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)


    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.

  19. A compact ESPI system for displacement measurements of specular reflecting or optical rough surfaces

    DEFF Research Database (Denmark)

    Hansen, R.S.


    A stable and compact speckle interferometer for doing out-of-plane displacement measurements on reflective as well as diffusely scattering object surfaces is demonstrated. The set-up is based on a nearly path length compensated interferometer of the Fizeau type and uses diffuse illumination...... of the object combined with a speckled reference wave. This combination eliminates the need for special optical components, and the interferometer can be built of commonly available components. The diffuse illumination wave is obtained by scattering coherent light from a diffusely scattering surface....... The speckled reference wave is established by reflecting a part of the diffuse illumination wave from a glass plate placed in front of the object. Besides relaxing the alignment tolerances of the set-up, the diffuse illumination eliminates the need for any preparation of the surface under test, which turns...

  20. Simulation of an oil film at the sea surface and its radiometric properties in the SWIR (United States)

    Schwenger, Frédéric; Van Eijk, Alexander M. J.


    The knowledge of the optical contrast of an oil layer on the sea under various surface roughness conditions is of great interest for oil slick monitoring techniques. This paper presents a 3D simulation of a dynamic sea surface contaminated by a floating oil film. The simulation considers the damping influence of oil on the ocean waves and its physical properties. It calculates the radiance contrast of the sea surface polluted by the oil film in relation to a clean sea surface for the SWIR spectral band. Our computer simulation combines the 3D simulation of a maritime scene (open clear sea/clear sky) with an oil film at the sea surface. The basic geometry of a clean sea surface is modeled by a composition of smooth wind driven gravity waves. Oil on the sea surface attenuates the capillary and short gravity waves modulating the wave power density spectrum of these waves. The radiance of the maritime scene is calculated in the SWIR spectral band with the emitted sea surface radiance and the specularly reflected sky radiance as components. Wave hiding and shadowing, especially occurring at low viewing angles, are considered. The specular reflection of the sky radiance at the clean sea surface is modeled by an analytical statistical bidirectional reflectance distribution function (BRDF) of the sea surface. For oil at the sea surface, a specific BRDF is used influenced by the reduced surface roughness, i.e., the modulated wave density spectrum. The radiance contrast of an oil film in relation to the clean sea surface is calculated for different viewing angles, wind speeds, and oil types characterized by their specific physical properties.

  1. Intensity distributions of reflected surface channeling protons scattered on surfaces of electron-bombarded alkali halide crystals (United States)

    Fukazawa, Y.; Kihara, K.; Iwamoto, K.; Susuki, Y.


    We have examined the surface-channeling of 550 keV protons on electron-bombarded KBr(0 0 1) surfaces at grazing incidence. On the surface, electron-stimulated desorption (ESD) resulting from the irradiation of 5 keV electrons changes the surface morphology. In order to investigate the change of the surface morphology, the luminous intensity distributions observed on a fluorescent screen (scattering patterns) of the reflected protons under the surface-channeling conditions are measured. Normalized specular intensity of the protons oscillates, and the results of computer simulations show that the period of the intensity oscillation agrees with the period of layer-by-layer desorption. The measured period of the oscillation is comparable to the simulated one, i.e., the period of the desorption, however, the measured amplitude of the oscillation is weak. This shows that the layer-by-layer desorption of the experimental surface is observed but is not as remarkable as that of the perfect surface introduced in the simulation.

  2. Intensity distributions of reflected surface channeling protons scattered on surfaces of electron-bombarded alkali halide crystals

    Energy Technology Data Exchange (ETDEWEB)

    Fukazawa, Y., E-mail:; Kihara, K.; Iwamoto, K.; Susuki, Y.


    We have examined the surface-channeling of 550 keV protons on electron-bombarded KBr(0 0 1) surfaces at grazing incidence. On the surface, electron-stimulated desorption (ESD) resulting from the irradiation of 5 keV electrons changes the surface morphology. In order to investigate the change of the surface morphology, the luminous intensity distributions observed on a fluorescent screen (scattering patterns) of the reflected protons under the surface-channeling conditions are measured. Normalized specular intensity of the protons oscillates, and the results of computer simulations show that the period of the intensity oscillation agrees with the period of layer-by-layer desorption. The measured period of the oscillation is comparable to the simulated one, i.e., the period of the desorption, however, the measured amplitude of the oscillation is weak. This shows that the layer-by-layer desorption of the experimental surface is observed but is not as remarkable as that of the perfect surface introduced in the simulation.

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

  4. Modifying Earth's Insolation with Aerosols: Reflectance and Polarization Properties of Candidate Particulate Materials (United States)

    Nelson, R. M.; Boryta, M. D.; Hapke, B. W.; Manatt, K. S.; Shkuratov, Y.; Vandervoort, K.; Vides, C.; Quinones, J.


    We report reflectance phase curves of selected materials, including several that, if distributed as particulate aerosols, might regulate solar insolation and hence reduce Earth's surface temperature. (See e.g. Teller et al., 1997). We have identified several materials that have phase functions that are remarkably backscattering at very small phase angles (Nelson et al., 2017). When these materials are of appropriately small particle size and in the form of dispersed discrete random media, they are highly reflective at ultraviolet and visual wavelengths. Particles of less than 0.5 microns in diameter are transparent in the infrared. The most promising of these is the mineral halite (NaCl). NaCl and its sister materials exhibit this property due to their simple cubic crystal structure. In crystalline form they are `corner cube' reflectors similar to those on bicycle reflectors used throughout the world, and in arrays deployed by astronauts on the Moon for precise distance determination. As aerosols distributed in relatively small quantities, NaCl might reduce the solar forcing function by several W/m2, the amount estimated by the IPCC to be the anthropogenic contribution to global warming. Furthermore, NaCl is environmentally benign and, as a particulate aerosol, it would have short residence time in the atmosphere. With great trepidation, we suggest potential use in these areas: Temporary regional application to mitigate short-term, life-threatening conditions in areas where extreme temperature events are expected on timescales of days, and Global application for immediate relief during a near-term transition period to an atmosphere that is generally free of anthropogenic greenhouse gas. We offer this as a temporary relief measure and not a solution, somewhat analogous to the application of morphine in a medical situation. This work partially supported by NASA's Cassini Orbiter Program

  5. 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.


    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...

  6. Modeling of Microwave Reflection from the Surface of Water Basins with Spills of Water-Cut Oil (United States)

    Krotikov, V. D.; Pelushenko, S. A.; Rakut', I. V.; Savelyev, V. Yu.


    We consider specific features of reflection of microwaves from the surface of a water basin for the two-layer model of oil spills, which are determined by a water-cut-oil film. Within the spill model, the dielectric properties of water were allowed for in accordance with the Debye theory, and the dielectric properties of the water-cut oil, in accordance with the theory developed for binary systems. The data about variations in the values of reflection coefficients depending on the frequency, viewing angle, thickness of the oil film, and moisture content in the film are obtained. The dependences of reflection coefficients on the film thickness are determined for various values of volume content of the water fraction in oil. Complex values of the dielectric permittivity of oil-water emulsions with preset volume moisture content are found. Describing the obtained dependences of the complex dielectric permittivity of the emulsion on the volume moisture content requires application of asymmetrical formulas for the mixture of polar and nonpolar fluids.

  7. Spectral reflectance properties of black chrome for use as a solar selective coating (United States)

    Mcdonald, G. E.


    The NASA-Lewis Research Center has determined that a widely available commercially electroplated decorative finish known as black chrome has desirable solar selective properties. Black chrome electroplated coating has high absorbtance in the solar spectrum and low emissivity in the 250 F blackbody thermal spectrum. The spectral reflectance properties of a commercially prepared black chrome on steel have been measured. Values are presented for reflectance of the black chrome, and compared with the reflectance of black paint and with two available samples of black nickel which had been prepared for solar selective properties. The reflectance of black chrome, of the two black nickels, and of black paint integrated over the solar spectrum for air mass 2 were 0.132, 0.123, 0.133, and 0.033, respectively. The reflectance of the black chrome, two black nickels, and of the black paint integrated over the blackbody spectrum for 250 F from 3 to 15 microns are 0.912, 0.934, 0.891, and 0.033, respectively. These reflectance measurements indicate absorptivity-to-emissivity values of 9.8, 13.8, 8.0, and 1.00, respectively.

  8. 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


    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.

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

    Directory of Open Access Journals (Sweden)

    Hu Zhang


    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.

  10. Correlation characteristics of signals reflected by the wavy surface of ocean in mirror direction (United States)

    Zhitkovskiy, Y. Y.; Nosov, A. V.; Savelyev, V. V.


    An experimental study was carried out to determine the correlation characteristics of pseudonoise signals reflected from a wave-covered surface in the mirror direction. The major measured quantity was the reciprocal correlation coefficient between the transmitted signal and the reflected signal. The transmitter was lowered from a ship on a 150 m cable. The receiver and preamplifier were lowered to the same depth from a buoy which was allowed to drift from the ship to a distance of 100-500 m, the changing distance changing the angle of the beam reflected from the surface of the ocean back down to the hydrophone. The radiator transmitted a pulsed signal with a pseudonoise carrier. The results were interpreted within the framework of ordinary correlation theory by processing several recordings, calculating the sign and ordinary correlation coefficients to determine the variation in sign correlation coefficient as a function of the ordinary correlation coefficient. Graphs of the average variation are presented. It was found that the medium did not distort the signal as it propagated through the water mass (within the limits of experimental accuracy). The correlation coefficient between the transmitted and reflected signals is thus determined entirely by the characteristics of reradiation of the sound by the wavecovered surface.

  11. Modification of surface properties of copper-refractory metal alloys (United States)

    Verhoeven, J.D.; Gibson, E.D.


    The surface properties of copper-refractory metal (CU-RF) alloy bodies are modified by heat treatments which cause the refractory metal to form a coating on the exterior surfaces of the alloy body. The alloys have a copper matrix with particles or dendrites of the refractory metal dispersed therein, which may be niobium, vanadium, tantalum, chromium, molybdenum, or tungsten. The surface properties of the bodies are changed from those of copper to that of the refractory metal.

  12. Impact of surface coal mining on soil hydraulic properties (United States)

    X. Liu; J. Q. Wu; P. W. Conrad; S. Dun; C. S. Todd; R. L. McNearny; William Elliot; H. Rhee; P. Clark


    Soil erosion is strongly related to soil hydraulic properties. Understanding how surface coal mining affects these properties is therefore important in developing effective management practices to control erosion during reclamation. To determine the impact of mining activities on soil hydraulic properties, soils from undisturbed areas, areas of roughly graded mine...

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

    CSIR Research Space (South Africa)

    Roy, DP


    Full Text Available of fire effects using multi-temporal reflective wavelength data D. P. Roy a; T. Landmann ba Department of Geography, College Park, and NASA Goddard, Space Flight Center, University of Maryland. Code 614.5 (B32), Greenbelt, MD 20771. USAb CSIR Environmentek... Characterizing the surface heterogeneity of fire effects using multi-temporal reflective wavelength data D. P. ROY*{ and T. LANDMANN{ {Department of Geography, University of Maryland, College Park, and NASA Goddard, Space Flight Center, Code 614.5 (B32...

  14. The Surface Chemical Properties of Novel High Surface Area Solids ...

    African Journals Online (AJOL)

    during zeolite synthesis.22 Because raw fly ash has large quanti- ties of a host of elements, many of these will act as nucleation sites, which results in many small crystals rather than a few large ones. Acid etching removed the needle-like structures on the particle surfaces, revealing a porous underlying structure. (Fig. 1c).

  15. Structure and optical properties of water covered Cu(110) surfaces

    International Nuclear Information System (INIS)

    Baghbanpourasl, A.


    In this thesis structural and optical properties of the water covered Cu(110) surface is studied using density functional theory within independent particle approximation. Several stable adsorption structures are studied such as water clusters (monomer, dimer, trimer, tetramer and pentamer), different hexagonal monolayers, partially dissociated water monolayers and three different types of chains among them a chain that consists of pentagon rings. For a copper surface in contact with water vapor, the energetically stable H 2 O/OH adsorbed structures are compared thermodynamically using adsorption free energy (change of free energy due to adsorption). Several phase diagrams with respect to temperature and pressure are calculated. It is found that among the large number of energetically stable structures (i.e. structures with positive adsorption energy ) only limited number of them are thermodynamically stable. These thermodynamically stable structures are the class of almost energetically degenerate hexagonal overlayers, one type of partially dissociated water structure that contains Bjerrum defect in the hydrogen bond network and pentagon chain. Since hydrogen atoms are light weight their vibrational effects can be considerable. Zero point vibration decreases the adsorption energy up to 0.1 eV and free energy of adsorbed molecules arising from vibrational degree of freedom can go up to -0.2 eV per adsorbed molecule at 500 Kelvin. However zero point energy and vibrational free energy of adsorbed molecules do not alter relative stability of the adsorbed structures. To account for the long range van der Waals interactions, a semi-empirical scheme is applied. Reflectance Anisotropy Spectroscopy (RAS) is a fast and non destructive optical method that can be used to prob the surface in different conditions such as vacuum and electro-chemical environment. Elasto-optic coeficients of bulk are calculated from first principles and the change of the RA spectrum of the bare Cu

  16. Studies of float glass surfaces by neutron and x-ray reflection

    International Nuclear Information System (INIS)

    Dalgliesh, R.


    The surface of glass and glass coatings have been studied using x-ray and neutron scattering techniques. In particular, the effect of aqueous solutions and humid atmospheres on both the fire polished and the tin rich side of float glass have been investigated using neutron and x-ray reflection. Isotopic substitution has enabled the number density of water molecules within the float glass surface to be monitored with respect to immersion time, temperature and impurity content. A thin gel-like water-rich layer of thickness ∼30A is observed at the surface accompanied by a more deeply penetrating layer which increases in depth with time reaching ∼500A after 6 months. The rate of water ingression is higher than predicted from previous work carried out at elevated temperatures. Small decreases in the depth of penetration have been observed for glass containing alumina and tin. Water penetration into thin films made by a sol-gel process have also been studied. The hydrophobicity of these films had been varied by the addition of fluoroalkylsilane. Neutron and X-ray reflection revealed that water entered the highly hydrophobic films readily from the vapour phase. This suggests a method of film destabilisation by which water enters the film and freezes, causing the film to crack. Changes in fluoroalkylsilane content and annealing have little effect on the penetration of water into the coatings. Etched float glass surfaces have been used as a system for testing the applicability of current off-specular scattering models. A rich surface structure has been found which results in reflection effects that cannot be explained by these models. Model systems have also been developed in an attempt to combine x-ray fluorescence techniques with reflectivity. (author)

  17. Antifouling polymer brushes displaying antithrombogenic surface properties

    Czech Academy of Sciences Publication Activity Database

    de los Santos Pereira, Andres; Sheikh, S.; Blaszykowski, C.; Pop-Georgievski, Ognen; Fedorov, K.; Thompson, M.; Rodriguez-Emmenegger, Cesar


    Roč. 17, č. 3 (2016), s. 1179-1185 ISSN 1525-7797 R&D Projects: GA ČR(CZ) GJ15-09368Y; GA MŠk(CZ) ED1.1.00/02.0109 Grant - others:OPPK(XE) CZ.2.16/3.1.00/21545 Program:OPPK Institutional support: RVO:61389013 Keywords : polymer brushes * surface characterization * antifouling surfaces Subject RIV: BO - Biophysics Impact factor: 5.246, year: 2016

  18. 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: [University of Paderborn, Department of Physics, 33098 Paderborn (Germany); Center of Optoelectronics and Photonics Paderborn CeOPP, 33098 Paderborn (Germany)


    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.

  19. An attenuated total reflectance IR study of silicic acid adsorbed onto a ferric oxyhydroxide surface (United States)

    Swedlund, Peter J.; Miskelly, Gordon M.; McQuillan, A. James


    Silicic acid (H 4SiO 4) can have significant effects on the properties of iron oxide surfaces in both natural and engineered aquatic systems. Understanding the reactions of H 4SiO 4 on these surfaces is therefore necessary to describe the aquatic chemistry of iron oxides and the elements that associate with them. This investigation uses attenuated total reflectance infrared spectroscopy (ATR-IR) to study silicic acid in aqueous solution and the products formed when silicic acid adsorbs onto the surface of a ferrihydrite film in 0.01 M NaCl at pH 4. A spectrum of 1.66 mM H 4SiO 4 at pH 4 (0.01 M NaCl) has an asymmetric Si-O stretch at 939 cm -1 and a weak Si-O-H deformation at 1090 cm -1. ATR-IR spectra were measured over time (for up to 7 days) for a ferrihydrite film (≈1 mg) approaching equilibrium with H 4SiO 4 at concentrations between 0.044 and 0.91 mM. Adsorbed H 4SiO 4 had a broad spectral feature between 750 and 1200 cm -1 but the shape of the spectra changed as the amount of H 4SiO 4 adsorbed on the ferrihydrite increased. When the solid phase Si/Fe mole ratio was less than ≈0.01 the ATR-IR spectra had a maximum intensity at 943 cm -1 and the spectral shape suggests that a monomeric silicate species was formed via a bidentate linkage. As the solid phase Si/Fe mole ratio increased to higher values a discrete oligomeric silicate species was formed which had maximum intensity in the ATR-IR spectra at 1001 cm -1. The spectrum of this species suggests that it is larger than a dimer and it was tentatively identified as a cyclic tetramer. A small amount of a polymeric silica phase with a broad spectral feature centered at ≈1110 cm -1 was also observed at high surface coverage. The surface composition was estimated from the relative contribution of each species to the area of the ATR-IR spectra using multivariate curve resolution with alternating least squares. For a ferrihydrite film approaching equilibrium with 0.044, 0.14, 0.40 and 0.91 mM H 4SiO 4 the

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

  1. Measuring and modeling near-surface reflected and emitted radiation fluxes at the FIFE site (United States)

    Blad, Blaine L.; Walter-Shea, Elizabeth A.; Starks, Patrick J.; Vining, Roel C.; Hays, Cynthia J.; Mesarch, Mark A.


    Information is presented pertaining to the measurement and estimation of reflected and emitted components of the radiation balance. Information is included about reflectance and transmittance of solar radiation from and through the leaves of some grass and forb prairie species, bidirectional reflectance from a prairie canopy is discussed and measured and estimated fluxes are described of incoming and outgoing longwave and shortwave radiation. Results of the study showed only very small differences in reflectances and transmittances for the adaxial and abaxial surfaces of grass species in the visible and infrared wavebands, but some differences in the infrared wavebands were noted for the forbs. Reflectance from the prairie canopy changed as a function of solar and view zenith angles in the solar principal plane with definite asymmetry about nadir. The surface temperature of prairie canopies was found to vary by as much as 5 C depending on view zenith and azimuth position and on the solar azimuth. Aerodynamic temperature calculated from measured sensible heat fluxes ranged from 0 to 3 C higher than nadir-viewed temperatures. Models were developed to estimate incoming and reflected shortwave radiation from data collected with a Barnes Modular Multiband Radiometer. Several algorithms for estimating incoming longwave radiation were evaluated and compared to actual measures of that parameter. Net radiation was calculated using the estimated components of the shortwave radiation streams, determined from the algorithms developed, and from the longwave radiation streams provided by the Brunt, modified Deacon, and the Stefan-Boltzmann models. Estimates of net radiation were compared to measured values and found to be within the measurement error of the net radiometers used in the study.

  2. Tuning antimicrobial properties of biomimetic nanopatterned surfaces. (United States)

    Michalska, Martyna; Gambacorta, Francesca; Divan, Ralu; Aranson, Igor S; Sokolov, Andrey; Noirot, Philippe; Laible, Philip D


    Nature has amassed an impressive array of structures that afford protection from microbial colonization/infection when displayed on the exterior surfaces of organisms. Here, controlled variation of the features of mimetics derived from etched silicon allows for tuning of their antimicrobial efficacy. Materials with nanopillars up to 7 μm in length are extremely effective against a wide range of microbial species and exceed the performance of natural surfaces; in contrast, materials with shorter/blunter nanopillars (<2 μm) selectively killed specific species. Using a combination of microscopies, the mechanisms by which bacteria are killed are demonstrated, emphasizing the dependence upon pillar density and tip geometry. Additionally, real-time imaging reveals how cells are immobilized and killed rapidly. Generic or selective protection from microbial colonization could be conferred to surfaces [for, e.g., internal medicine, implants (joint, dental, and cosmetic), food preparation, and the agricultural industry] patterned with these materials as coatings.

  3. 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.


    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

  4. Surface plasmon resonance sensors based on uniform-waist tapered fibers in a reflective configuration (United States)

    Esteban, Óscar; Díaz-Herrera, Natalia; Navarrete, María-Cruz; González-Cano, Agustín


    We present a configuration for surface plasmon resonance sensors based on uniform-waist tapered optical fibers and reflective elements. Once the fiber is tapered fulfilling the adiabatic criterion, a multilayer including a metallic medium is asymmetrically deposited on the uniform waist of the fiber. This feature provides the resonant excitation of multiple surface plasma waves. In addition, a mirror is produced at the fiber tip by a chemical Tollens reaction. In this way, the sensor operates in a reflective mode, more convenient for dip probes. When these sensors are spectrally interrogated, a high sensitivity of 10-4 refractive index units per nanometer is attained. These devices can be advantageously used for any kind of chemical sensing and biosensing.

  5. 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.


    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)

  6. Structural and electronic properties of hydrosilylated silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Baumer, A.


    The structural and electronic properties of alkyl-terminated Si surfaces prepared by thermallyinduced hydrosilylation have been studied in detail in the preceding chapters. Various surfaces have been used for the functionalization ranging from crystalline Si over amorphous hydrogenated Si to nanoscaled materials such as Si nanowires and nanoparticles. In each case, the alkyl-terminated surfaces have been compared to the native oxidized and H-terminated surfaces. (orig.)

  7. Composition and physical properties of Enceladus' surface (United States)

    Brown, R.H.; Clark, R.N.; Buratti, B.J.; Cruikshank, D.P.; Barnes, J.W.; Mastrapa, R.M.E.; Bauer, J.; Newman, S.; Momary, T.; Baines, K.H.; Bellucci, G.; Capaccioni, F.; Cerroni, P.; Combes, M.; Coradini, A.; Drossart, P.; Formisano, V.; Jaumann, R.; Langavin, Y.; Matson, D.L.; McCord, T.B.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe


    Observations of Saturn's satellite Enceladus using Cassini's Visual and Infrared Mapping Spectrometer instrument were obtained during three flybys of Enceladus in 2005. Enceladus' surface is composed mostly of nearly pure water ice except near its south pole, where there are light organics, CO2, and amorphous and crystalline water ice, particularly in the region dubbed the "tiger stripes." An upper limit of 5 precipitable nanometers is derived for CO in the atmospheric column above Enceladus, and 2% for NH 3 in global surface deposits. Upper limits of 140 kelvin (for a filled pixel) are derived for the temperatures in the tiger stripes.

  8. Manganese phospate physical chemistry and surface properties

    International Nuclear Information System (INIS)

    Najera R, N.; Romero G, E. T.


    This paper presents the methodology for the manganese phosphate (III) synthesis (MnP0 4 H 2 0) from manganese chloride. The physicochemical characterization was carried out by: X-ray diffraction, scanning electron microscopy, infrared analysis and thermal gravimetric analysis. The surface characterization is obtained through the determination of surface area, point of zero charge and kinetics of moisture. As a phosphate compound of a metal with low oxidation state is a promising compound for removal pollutants from water and soil, can be used for the potential construction of containment barriers for radioactive wastes. (Author)

  9. 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 (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.


    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.

  10. Physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China (United States)

    Li, Qiong; Chen, Jie; He, Jian-Jun


    In this study, we experimentally established the relationship between physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China using representative coal samples collected from three different mines via the rock mechanics testing system (MTS). We analyzed the organic macerals, vitrinite reflectance, and microstructure of 11 coal samples using petrography and scanning electron microscopy (SEM). The experimental results suggest that (1) the elastic parameters can be described by linear equations, (2) both P-and S-wave velocities display anisotropy, (3) the anisotropy negatively correlates with vitrinite reflectance, and (4) the acoustic velocities and Young's modulus are negatively correlated with the volume of micropores. The derived empirical equations can be used in the forward modeling and seismic inversion of physical properties of coal for improving the coal-bed methane (CBM) reservoir characterization.

  11. Transitioning MODIS to VIIRS observations for Land: Surface Reflectance results, Status and Long-term Prospective (United States)

    Vermote, E.


    Surface reflectance is one of the key products from VIIRS and as with MODIS, is used in developing several higher-order land products. The VIIRS Surface Reflectance (SR) IP is based on the heritage MODIS Collection 5 product (Vermote et al. 2002). The quality and character of surface reflectance depends on the accuracy of the VIIRS Cloud Mask (VCM) and aerosol algorithms and of course on the adequate calibration of the sensor. Early evaluation of the VIIRS SR product in the context of the maturity of the operational processing system known as the Interface Data Processing System (IDPS), has been a major focus of work to-date, but is now evolving into the development of a VIIRS suite of Climate Data Records produced by the NASA Land Science Investigator Processing System (SIPS). We will present the calibration performance and the role of the surface reflectance in calibration monitoring, the performance of the cloud mask with a focus on vegetation monitoring (no snow conditions), the performance of the aerosol input used in the atmospheric correction with quantitative results of the performance of the SR product over AERONET sites. Based on those elements and further assessment, we will address the readiness of the SR product for the production of higher-order land products such as Vegetation Indices, Albedo and LAI/FPAR, the its application to agricultural monitoring and in particular the integration of VIIRS data into the global agricultural monitoring (GLAM) system developed at UMd. Finally from the lessons learned, we will articulate a set of critical recommendations to ensure consistency and continuity of the JPSS mission with the MODIS data record.

  12. 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.


    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

  13. Fluctuations of noiselike signals reflected from a rough surface at the output of a correlation receiver (United States)

    Gulin, E. P.


    The frequency and time averaging of the fluctuations that occur in the cross-correlation function of a radiated noiselike acoustic signal with the signal received after its reflection from a rough water surface is considered. The variance and temporal correlation function are calculated for the output effect of a correlation receiver for different ratios between the averaging time and the time correlation interval of fluctuations, the band width of the radiated signal, and the frequency correlation interval of the transfer function fluctuations.

  14. 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.


    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

  15. Decadal changes of surface elevation over permafrost area estimated using reflected GPS signals (United States)

    Liu, Lin; Larson, Kristine M.


    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.

  16. A Study on Infrared Emissivity Measurement of Material Surface by Reflection Method

    International Nuclear Information System (INIS)

    Kang, Byung Chul; Kim, Sang Myoung; Choi, Joung Yoon; Kim, Gun Ok


    Infrared emissivity is one of the most important factors for the temperature measurement by infrared thermography. Although the infrared emissivity of an object can be measured from the ratio of blackbody and the object, at room temperature it is practically difficult to measure the value due to the background effects. Hence, quantitative reflectance of bare steel plate and the surface of coating was measured by FT-IR spectroscopy and emissivity was calculated from this. The emissivity of polished bare steel surface was from 0.06 to 0.10 and the value for the unpolished bare steel can not be achieved because optical characteristics changes of surface roughness induces erroneous results. Emissivity of transparent paint coated steel was from 0.50 to 0.84. Depends on the IR absorption regions, which is a characteristic value of the coating, emissivity changes. This study suggests surface condition of material, thickness, roughness etcetra are important factor for IR optical characteristics. Emissivity measurement by reflection method is useful technique to be applied for metal and it with coating applied on the surface. The range of experimental errors of temperature can be narrowed by the application of infrared thermography from the measured thermal emissivity

  17. surface properties of electrochemically reduced viscose rayon ...

    African Journals Online (AJOL)


    A viscose rayon based activated carbon cloth (ACC) was electrochemically reduced under a wide ... Electrochemical reduction resulted in a loss of 28% BET surface .... electrodes. As shown in. Figure 1. Schematic of the electrochemical cell used for electrochemical reduction. Figure 1, the anodes were placed at equal.


    African Journals Online (AJOL)

    Perovskite-type La2 –xSrxCoO4 mixed oxides have been prepared by calcination at various temperatures of precipitates obtained from aqueous solutions in the presence of citric or ethylenediamintetraacetic (EDTA) acids, and have been studied by X-ray diffraction (XRD), surface area (BET) measurements, temperature ...

  19. Wetting Properties of Molecularly Rough Surfaces

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Martin; Malijevský, Alexandr; Lísal, Martin


    Roč. 143, č. 10 (2015), s. 104701 ISSN 0021-9606 R&D Projects: GA ČR GA13-09914S; GA MŠk LH12020 Institutional support: RVO:67985858 Keywords : contant-angle * solid-surface * dynamics Subject RIV: BJ - Thermodynamics Impact factor: 2.894, year: 2015

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

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Shuai; Hu, Peng-Cheng, E-mail:; Ding, Xue-Mei, E-mail:; Tan, Jiu-Bin [Harbin Institute of Technology, D-403 Science Park, 2 Yikuang Street, Harbin 150080 (China)


    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.

  1. A fiber-coupled displacement measuring interferometer for determination of the posture of a reflective surface (United States)

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


    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.

  2. A rendering method of background reflections on a specular surface for CGH

    International Nuclear Information System (INIS)

    Ichikawa, T; Sakamoto, Y


    Computer-generated holograms (CGHs) are remarked as ideal three-dimensional displays. There are a lot of problems have to be overcome, and we focused on the rendering techniques to reconstruct realistic images. In particular, there is almost no calculation method that correctly expresses depth information. Reflected images are necessary to express complex realistic scenes. In this paper, we introduce a calculation method that generates reconstructed images with background reflections. Proposed method calculates intersections between virtual objects and rays by the ray tracing method. Then intersections are assumed as a point light source group, and light waves on a hologram plane are calculated. In the ray tracing process, when a ray hits the specular object, a ray is additionally casted to the specular direction from the intersection. If the ray hits other diffuse objects or background, the length of light path from a viewpoint to the diffuse object is calculated. By calculating light waves from a point light source on the diffuse surface distant from the light path, reflected images are expressed in the CGH. To express the quality of materials, we adopted the Cook-Torrance reflection model. In the experiment, we conducted the computer simulation to confirm that the depth of reflected images is correctly calculated. And results of optical reconstructions show that our proposed method is able to make CGHs of various qualities of material.

  3. 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.


    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

  4. Beam profile and coherence properties of synchrotron beams after reflection on modified multilayer mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Rack, Alexander, E-mail:; Vivo, Amparo; Morawe, Christian [European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble (France); Helfen, Lukas [European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble (France); ANKA light source, Karlsruhe Institute of Technology, PO Box 3640, D-76021 Karlsruhe (Germany)


    Multilayer mirrors present an attractive alternative for reflective hard X-ray monochromators due to their increased bandwidth compared with crystal-based systems. An issue remains the strong modulations in the reflected beam profile, i.e. an irregular stripe pattern. This is a major problem for micro-imaging applications, where multilayer-based monochromators are frequently employed to deliver higher photon flux density. A subject of particular interest is how to overcome beam profile modifications, namely the stripe patterns, induced by the reflection on a multilayer. For multilayer coatings in general it is known that the substrate and its surface quality significantly influence the performance of such kind of mirrors as the coating reproduces to a certain degree roughness and shape of the substrate. Our studies have shown that modified coatings can significantly change the impact of the multilayer reflection on the beam profile. We will present recent results as well as a critical review.

  5. NPP/VIIRS Surface Reflectance Daily L2G Global 1km and 500m SIN Grid NRT (United States)

    National Aeronautics and Space Administration — The VNP09GA_NRT is a Near Real Time (NRT) S-NPP/VIIRS 500m and 1km Daily Level 2G Surface Reflectance product. The NPP/ VIIRS surface reflectance products are...

  6. [Biological properties of Lactobacillus surface proteins]. (United States)

    Buda, Barbara; Dylus, Ewa; Górska-Frączek, Sabina; Brzozowska, Ewa; Gamian, Andrzej


    Lactobacillus, a genus of Gram-positive bacteria, includes many strains of probiotic microflora. Probiotics, by definition, are living microorganisms that exert beneficial effects on the host organism. The morphology and physiology of the Lactobacillus bacterial genus are described. The structure of the cell wall of Gram-positive bacteria is discussed. The surface S-layer of Lactobacillus composed of proteins (SLP) with low molecular mass is presented. Cell surface proteins participating in the regulation of growth and survival of the intestinal epithelium cells are characterized. The influence of stress factors such as increased temperature, pH, and enzymes of gastric and pancreatic juice on SLP expression is described. The ability of binding of heavy metal ions by S-layer proteins is discussed. The characteristics of these structures, including the ability to adhere to epithelial cells, and the inhibition of invasion of pathogenic microflora of type Shigella, Salmonella, Escherichia coli and Clostridium and their toxins, are presented. 

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

    Petronio, Lorenzo; Boaga, Jacopo; Cassiani, Giorgio


    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.

  8. Sputtering properties of tungsten 'fuzzy' surfaces

    International Nuclear Information System (INIS)

    Nishijima, D.; Baldwin, M.J.; Doerner, R.P.; Yu, J.H.


    Sputtering yields of He-induced W 'fuzzy' surfaces bombarded by Ar have been measured in the linear divertor plasma simulator PISCES-B. It is found that the sputtering yield of a fuzzy surface, Y fuzzy , decreases with increasing fuzzy layer thickness, L, and saturates at ∼10% of that of a smooth surface, Y smooth , at L > 1 μm. The reduction in the sputtering yield is suspected to be due mainly to the porous structure of fuzz, since the ratio, Y fuzzy /Y smooth follows (1 - p fuzz ), where p fuzz is the fuzz porosity. Further, Y fuzzy /Y smooth is observed to increase with incident ion energy, E i . This may be explained by an energy dependent change in the angular distribution of sputtered W atoms, since at lower E i , the angular distribution is observed to become more butterfly-shaped. That is, a larger fraction of sputtered W atoms can line-of-sight deposit/stick onto neighboring fuzz nanostructures for lower E i butterfly distributions, resulting in lower ratio of Y fuzzy /Y smooth .

  9. Simultaneous Evaluation of Cerebral Hemodynamics and Light Scattering Properties of the In Vivo Rat Brain Using Multispectral Diffuse Reflectance Imaging. (United States)

    Nishidate, Izumi; Mustari, Afrina; Kawauchi, Satoko; Sato, Shunichi; Sato, Manabu


    The simultaneous evaluation of cerebral hemodynamics and the light scattering properties of in vivo rat brain tissue is demonstrated using a conventional multispectral diffuse reflectance imaging system. This system is constructed from a broadband white light source, a motorized filter wheel with a set of narrowband interference filters, a light guide, a collecting lens, a video zoom lens, and a monochromatic charged-coupled device (CCD) camera. An ellipsoidal cranial window is made in the skull bone of a rat under isoflurane anesthesia to capture in vivo multispectral diffuse reflectance images of the cortical surface. Regulation of the fraction of inspired oxygen using a gas mixture device enables the induction of different respiratory states such as normoxia, hyperoxia, and anoxia. A Monte Carlo simulation-based multiple regression analysis for the measured multispectral diffuse reflectance images at nine wavelengths (500, 520, 540, 560, 570, 580, 600, 730, and 760 nm) is then performed to visualize the two-dimensional maps of hemodynamics and the light scattering properties of the in vivo rat brain.

  10. A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics. [acid-base properties of titanium 6-4 surfaces (United States)

    Siriwardane, R.; Wightman, J. P.


    The acid-base properties of titanium 6-4 plates (low surface area) were investigated after three different pretreatments, namely Turco, phosphate-fluoride and Pasa-Jell. A series of indicators was used and color changes were detected using diffuse reflectance visible spectroscopy. Electron spectroscopy for chemical analysis was used to examine the indicator on the Ti 6-4 surface. Specular reflectance infra-red spectroscopy was used to study the adsorption of stearic acid from cyclohexane solutions on the Ti 6-4 surface.

  11. Incisor inclination determined by the light reflection zone on the tooth's surface. (United States)

    Brezniak, Naphtali; Turgeman, Ronit; Redlich, Meir


    Maxillary incisors are the most prominent teeth, and their inclination plays an important role in esthetics. In orthodontics, the inclination of central incisors is usually determined by cephalometric analysis. This publication suggests an adjunctive clinical measure to determine this inclination. The objective of the study was to examine the correlation between the inclinations of maxillary incisors measured on a cephalometric lateral headfilm and the light reflection zone appearing on the buccal surface of the teeth on anterior intraoral photographs. Maxillary incisor inclination, divided into three levels-proclination, normal inclination, and retroclination-of 65 patients was determined by means of cephalometric analysis, using three angular measurements (maxillary incisor to sella-nasion, maxillary incisor to Frankfort horizontal, and maxillary incisor to nasion-point A). The anterior intraoral photographs of the 65 patients were divided into 3 groups according to the reflection zone on the maxillary central incisors as determined from the photographs: incisal, middle, and gingival. The correlation and agreement between the two parameters were evaluated by chi-square and kappa statistics. The light reflection zone on the tooth surface as it appears on intraoral photographs-incisal, middle, or gingival-correlated with statistical significance to the angular inclination of the teeth-proclination, normal inclination, and retroclination, respectively-as determined by means of cephalometric analysis (P light reflection zone viewed on the buccal surface of intraoral photographs. This method might be used as a new screening tool and further as an additional clinical tool for assessing treatment plans in orthodontics and other fields of dentistry.

  12. 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.


    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

  13. Surface conditions and viscoelastic properties of the denture liner Permaflex. (United States)

    Buch, D; Beal, Y


    This in vitro study evaluated the viscoelastic properties of Permaflex compared to other soft lining materials. The surface condition of this material was also investigated under both laboratory and simulated clinical conditions and with and without the application of a varnish. The tests provided practical instructions for the use of Permaflex, which showed good adaptive properties to stress and surface condition initially and after adjustment.

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

    International Nuclear Information System (INIS)

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


    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)

  15. Automatic and improved radiometric correction of Landsat imagery using reference values from MODIS surface reflectance images (United States)

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


    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

  16. Effect of retardation on the reflectance properties of the metallic Fibonacci quasi-superlattice

    International Nuclear Information System (INIS)

    Feng Weiguo; Yao Hesheng; Xu Xiang


    Based on the hydrodynamic model theory and the transfer matrix method, we have re-examined the reflection properties by taking account of the retardation effect to the system of the metallic Fibonacci quasi-superlattice. For the normal incident S-polarized Soft X-rays and extreme ultraviolet, we find that the self-similar reflecting spectrum will be restrained with the increasing of the retardation, but for the higher frequency region or at the smaller grazing angle, the self similarity will still exist for the lower generation quasi-superlattice. (author). 19 refs, 2 figs, 1 tab

  17. Self-generation of colligative properties at hydrophilic surfaces


    Chaplin, Martin


    The generally accepted view of osmotic pressure is that it is a colligative property, along with freezing point depression, boiling point elevation and vapour pressure lowering. These properties ideally depend on the concentration of dissolved solute molecules. Osmotic pressure, however, is also generated, without any solute, at hydrophilic surfaces. Here is presented a rationale and explanation for this phenomenon.

  18. Tailoring Silica Surface Properties by Plasma Polymerization for Elastomer Applications

    NARCIS (Netherlands)

    Tiwari, M.; Dierkes, Wilma K.; Datta, Rabin; Talma, Auke; Noordermeer, Jacobus W.M.; van Ooij, W.J.


    The surface properties of reinforcing fillers are a crucial factor for dispersion and filler–polymer interaction in rubber compounds, as they strongly influence the final vulcanized properties of the rubber article. Silica is gaining more and more importance as reinforcing filler for rubbers, as it

  19. Tailoring Silica Surface Properties by Plasma Polymerization for Elastomer Applications

    NARCIS (Netherlands)

    Tiwari, M.; Dierkes, W.K.; Datta, R.N.; Talma, A.G.; Noordermeer, J.W.M.; van Ooij, W.J.


    The surface properties of reinforcing fillers are a crucial factor for dispersion and filler–polymer interaction in rubber compounds, as they strongly influence the final vulcanized properties of the rubber article. Silica is gaining more and more importance as reinforcing filler for rubbers, as it

  20. Theoretical studies of mutual diffusivities and surface properties in ...

    Indian Academy of Sciences (India)

    properties, thus underlining the importance of thermodynamic studies for liquid binary alloys. In this study, the transport and surface properties of Cd–Ga liquid alloys are determined from energetics and derivatives from experimental thermodynamic data. Cd–Ga alloys have been studied by many authors [14–16]. The alloy ...

  1. Antibody adsorption on the surface of water studied by neutron reflection. (United States)

    Smith, Charles; Li, Zongyi; Holman, Robert; Pan, Fang; Campbell, Richard A; Campana, Mario; Li, Peixun; Webster, John R P; Bishop, Steven; Narwal, Rojaramani; Uddin, Shahid; van der Walle, Christopher F; Lu, Jian R


    Surface and interfacial adsorption of antibody molecules could cause structural unfolding and desorbed molecules could trigger solution aggregation, resulting in the compromise of physical stability. Although antibody adsorption is important and its relevance to many mechanistic processes has been proposed, few techniques can offer direct structural information about antibody adsorption under different conditions. The main aim of this study was to demonstrate the power of neutron reflection to unravel the amount and structural conformation of the adsorbed antibody layers at the air/water interface with and without surfactant, using a monoclonal antibody 'COE-3' as the model. By selecting isotopic contrasts from different ratios of H 2 O and D 2 O, the adsorbed amount, thickness and extent of the immersion of the antibody layer could be determined unambiguously. Upon mixing with the commonly-used non-ionic surfactant Polysorbate 80 (Tween 80), the surfactant in the mixed layer could be distinguished from antibody by using both hydrogenated and deuterated surfactants. Neutron reflection measurements from the co-adsorbed layers in null reflecting water revealed that, although the surfactant started to remove antibody from the surface at 1/100 critical micelle concentration (CMC) of the surfactant, complete removal was not achieved until above 1/10 CMC. The neutron study also revealed that antibody molecules retained their globular structure when either adsorbed by themselves or co-adsorbed with the surfactant under the conditions studied.

  2. Reflecting and Polarizing Properties of Conductive Fabrics in Ultra-High Frequency Range

    Directory of Open Access Journals (Sweden)

    Oleg Kiprijanovič


    Full Text Available The system based on ultra-wide band (UWB signals was employed for qualitative estimation of attenuating, reflecting and polarizing properties of conductive fabrics, capable to prevent local static charge accumulation. Pulsed excitation of triangle monopole antenna of 6.5 cm height by rectangular electric pulses induced radiation of UWB signals with spectral density of power having maximum in ultra-high frequency (UHF range. The same antenna was used for the radiated signal receiving. Filters and amplifiers of different passband were employed to divide UHF range into subranges of 0.3-0.55 GHz, 0.55-1 GHz, 1-2 GHz and 2-4 GHz bands. The free space method, when conductive fabric samples of 50x50 cm2 were placed between transmitting and receiving antennas, was used to imitate a practical application. Received wideband signals corresponding to the defined range were detected by unbiased detectors. The fabrics made of two types of warps, containing different threads with conductive yarns, were investigated. It was estimated attenuation and reflective properties of the fabrics when electric field is collinear or perpendicular to thread direction. In the UHF range it was revealed good reflecting properties of the fabrics containing metallic component in the threads. The system has advantages but not without a certain shortcoming. Adapting it for specific tasks should lead to more effective usage, including yet unused properties of the UWB signals.

  3. Surface properties and microporosity of polyhydroxybutyrate under scanning electron microscopy

    International Nuclear Information System (INIS)

    Raouf, A.A.; Samsudin, A.R.; Samian, R.; Akool, K.; Abdullah, N.


    This study was designed to investigate the surface properties especially surface porosity of polyhydroxybutyrate (PHB) using scanning electron microscopy. PHB granules were sprinkled on the double-sided sticky tape attached on a SEM aluminium stub and sputtered with gold (10nm thickness) in a Polaron SC515 Coater, following which the samples were placed into the SEM specimen chamber for viewing and recording. Scanning electron micrographs with different magnification of PHB surface revealed multiple pores with different sizes. (Author)

  4. Effects of surface treatment on the properties of UV coating


    Guo, Xiaolei; Li, Rongrong; Teng, Yu; Cao, Pingxiang; Wang, Xiaodong (Alice); Ji, Futang


    The influence of the surface treatment of raw medium-density fiberboard on the properties of 1st ultraviolet putty coating film and the effects of primer coating arrangement on the qualities of 1st ultraviolet primer film were investigated. With regard to surface roughness and the recorded adhesion of the coating film, there were significant variations when the surface treatment was modified or when the coating arrangement was changed. The findings led to the conclusion that there was a close...

  5. Characterizing LEDAPS surface reflectance products by comparisons with AERONET, field spectrometer, and MODIS data (United States)

    Maiersperger, Tom; Scaramuzza, Pat; Leigh, Larry; Shrestha, S.; Gallo, Kevin; Jenkerson, Calli B.; Dwyer, John L.


    This study provides a baseline quality check on provisional Landsat Surface Reflectance (SR) products as generated by the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center using Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) software. Characterization of the Landsat SR products leveraged comparisons between aerosol optical thickness derived from LEDAPS and measured by Aerosol Robotic Network (AERONET), as well as reflectance correlations with field spectrometer and Moderate Resolution Imaging Spectroradiometer (MODIS) data. Results consistently indicated similarity between LEDAPS and alternative data products in longer wavelengths over vegetated areas with no adjacent water, while less reliable performance was observed in shorter wavelengths and sparsely vegetated areas. This study demonstrates the strengths and weaknesses of the atmospheric correction methodology used in LEDAPS, confirming its successful implementation to generate Landsat SR products.

  6. Reflection of X-rays from a rough surface at extremely small grazing angles. (United States)

    Wen, Mingwu; Kozhevnikov, Igor V; Wang, Zhanshan


    Peculiarities of X-ray diffraction from a rough surface at an extremely small grazing angle of an incident beam are theoretically studied. The interrelation of four diffraction channels (coherent reflectance, coherent transmittance, diffuse scattering in vacuum, and scattering into the matter depth) is analyzed for different limiting cases (large and small correlation length of roughness and large and extremely small grazing angle of incident radiation). Both the Debye-Waller and the Nevot-Croce factors are demonstrated to describe improperly the features of X-ray diffraction at extremely small grazing angles. More appropriate simple analytic expressions for the specular reflectivity and total integrated scattering in vacuum are obtained instead. Transformation of one limiting diffraction regime into another one with variation in the correlation length of roughness is discussed.

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

    Directory of Open Access Journals (Sweden)

    V. V. Leonov


    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.

  8. Influence of coffee on reflectance and chemistry of resin composite protected by surface sealant. (United States)

    Soares, Luís Eduardo Silva; Cesar, Ilene Cristine Rosia; Santos, Carla Gabriela Couto; De Cardoso, Ana Luiza Merigo Oliveira; Liporoni, Priscila Christiane Suzy; Munin, Egberto; Martin, Airton Abrahão


    To assess the influence of the light-curing unit type and whether or not it was worth using surface sealant protection on resin composite restorative materials stained by coffee. Another objective was to propose the monitoring of coffee staining by FT-Raman spectroscopy using carbon-hydrogen (C-H) bonds as reference to the composite matrix degradation. Sixty cylindrical specimens of resin composite were prepared and divided into six groups: HC (control)--cured with a halogen light; LC (control) cured with a LED; HF--cured with a halogen light + Fortify Plus; LF--cured with a LED + Fortify Plus; HP--cured with a halogen light + PermaSeal; LP--cured with a LED + PermaSeal. After storage for 24 hours at 37% and 100% of relative humidity, the top surface was protected, and the other surfaces isolated. Polishing with paper discs was performed after 24 hours of curing and prior to FT-Raman spectroscopy and reflectance measurements. All specimens were submitted to coffee staining for 14 days and evaluated by both systems. Results were statistically analyzed by ANOVA and Tukey tests. FT-Raman spectrum only showed significant changes in groups LC and LP (P< 0.05). Reflectance demonstrated that staining was present in all specimens protected by sealants. Sealant staining was larger in the HF (P < 0.001) group.

  9. Microwave reflection properties of planar anisotropy Fe50Ni50 powder/paraffin composites

    International Nuclear Information System (INIS)

    Wei Jian-Qiang; Zhang Zhao-Qi; Han Rui; Wang Tao; Li Fa-Shen


    The reflection properties of planar anisotropy Fe 50 Ni 50 powder/paraffin composites have been studied in the microwave frequency range. The permeability of Fe 50 Ni 50 powder/paraffin composites is greatly enhanced by introducing the planar anisotropy, and can be further enhanced by using a rotational orientation method. The complex permeability can be considered as the superposition of two types of magnetic resonance. The resonance peak at high frequency is attributed to the natural resonance, while the peak at low frequency is attributed to the domain-wall resonance. The simulated results of the microwave reflectivity show that the matching thickness, peak frequency, permeability, and permittivity are closely related to the quarter wavelength matching condition. The Fe 50 Ni 50 powder/paraffin composites can be attractive candidates for thinner microwave absorbers in the L-band (1–2 GHz). (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  10. High laser damage threshold surface relief micro-structures for anti-reflection applications (United States)

    Hobbs, Douglas S.; MacLeod, Bruce D.


    Microstructures built into the surfaces of an optic or window, are an effective replacement for thin-film coatings in anti-reflection (AR) and narrow-band filter applications. AR microstructures exhibit particularly noteworthy performance where an average reflection loss of less than 0.2% over a four-octave range (400-1800nm) has been demonstrated, and a loss of less than 0.03% is routinely achieved for narrow-band applications. Because AR micro-textures provide a gradual change in the refractive index at a material boundary, it is expected that light can propagate through the boundary without material damage at energy levels that are much higher than that found with thin-film interference coatings. Recently, it was shown that the laser induced damage threshold (LIDT) of an inexpensive borosilicate glass window containing AR microstructures was nearly 57 J/cm2 at 1064nm (20ns pulse). This LIDT is two to three times greater than the damage threshold of single-layer sol-gel AR coatings on fused silica often reported in the literature. The development of surface relief AR textures for use in high-energy laser applications is presented. Data from scanning electron microscope (SEM) analysis, reflection measurements, and LIDT testing, is shown for high performance AR microstructures fabricated in fused silica, and borosilicate glass. Results of LIDT testing at wavelengths ranging from the near ultraviolet through the near infrared confirm the initial result that AR microstructures can operate at pulsed laser power levels at least two times higher than thin-film coatings. For near infrared applications such as laser weapons and fiber optic communications requiring high performance AR, LIDT levels for AR microstructures in fused silica are found to be at least five times greater than conventional multi-layer thin film coatings. An initial surface absorption test at 1064nm shows that AR microstructures may also exhibit improved lifetimes within continuous wave laser systems.

  11. Attenuated total reflectance spectroscopy of coumarin organosilane molecules adsorbed on a fused silica surface

    International Nuclear Information System (INIS)

    Bratescu, Maria Antoaneta; Saito, Nagahiro; Takai, Osamu


    Attenuated total reflectance (ATR) spectroscopy was used to investigate the adsorption of coumarin organosilane molecules onto a fused silica surface. The difference between the absorption spectra of the molecules on the surface and in solution was explained by the interaction of the adsorbed coumarin organosilane molecules with the hydroxyl groups on the fused silica surface. This interaction produces a perturbation of the π electron distribution and the electronic transitions of the coumarin chromophore of the organosilane molecules adsorbed on the surface. From the kinetics adsorption curves, the calculated enthalpy values of 74.8 ± 5.2 kJ mol -1 and free energy of -38.22 ± 0.70 kJ mol -1 at 23 deg. C indicates a chemisorption process. The high sensitivity of ATR spectroscopy allows the detection of a monolayer formed by a 10 nM concentration of coumarin organosilane molecules, which covers more than half of the maximum surface coverage at 60 deg. C.

  12. Multipitched Diffraction Gratings for Surface Plasmon Resonance-Enhanced Infrared Reflection Absorption Spectroscopy. (United States)

    Petefish, Joseph W; Hillier, Andrew C


    We demonstrate the application of metal-coated diffraction gratings possessing multiple simultaneous pitch values for surface enhanced infrared absorption (SEIRA) spectroscopy. SEIRA increases the magnitude of vibrational signals in infrared measurements by one of several mechanisms, most frequently involving the enhanced electric field associated with surface plasmon resonance (SPR). While the majority of SEIRA applications to date have employed nanoparticle-based plasmonic systems, recent advances have shown how various metals and structures lead to similar signal enhancement. Recently, diffraction grating couplers have been demonstrated as a highly tunable platform for SEIRA. Indeed, gratings are an experimentally advantageous platform due to the inherently tunable nature of surface plasmon excitation at these surfaces since both the grating pitch and incident angle can be used to modify the spectral location of the plasmon resonance. In this work, we use laser interference lithography (LIL) to fabricate gratings possessing multiple pitch values by subjecting photoresist-coated glass slides to repetitive exposures at varying orientations. After metal coating, these gratings produced multiple, simultaneous plasmon peaks associated with the multipitched surface, as identified by infrared reflectance measurements. These plasmon peaks could then be coupled to vibrational modes in thin films to provide localized enhancement of infrared signals. We demonstrate the flexibility and tunability of this platform for signal enhancement. It is anticipated that, with further refinement, this approach might be used as a general platform for broadband enhancement of infrared spectroscopy.

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

    DEFF Research Database (Denmark)

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


    Current pig house cleaning procedures are hazardous to the health of farm workers, and yet necessary if the spread of disease between batches of animals is to be satisfactorily controlled. Autonomous cleaning using robot technology offers salient benefits. This report addresses the feasibility...... 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...

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

    DEFF Research Database (Denmark)

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


    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 co...... compounds. We model the physics as a change in the top mirror loss caused by swelling of the polymer upon absorbing the target volatile organic compound. Further we show how acetone vapors at 82 000 ppm concentration can change the polymer coated VCSEL output power by 20 mu W....

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

    Energy Technology Data Exchange (ETDEWEB)



    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)

  16. Optical properties study of silicone polymer PDMS substrate surfaces modified by plasma treatment (United States)

    Zahid, A.; Dai, B.; Hong, R.; Zhang, D.


    In this study, PDMS (polydimethylsiloxane) substrates with a half-plain, half-rough surface were prepared on a plain and rough fused silica glass substrate using a molding technique. The molded PDMS surface morphology was changed into a half-smooth and half-rough surface after peeling. The modified PDMS surfaces’ optical properties were inspected with and without treatment. The treatment is exposed by oxygen plasma (15 W) for 3 min in a vacuum, down to a pressure of six torr, using a vacuum pump. An atomic force microscope (AMF) and interferometer (white light) indicated that the plasma O2 treatment increased the formation of the plain surface and decreased the formation of the rough surface. The optical properties via a spectrophotometer (lambda) show the resonance from 300 nm to 1200 nm on the rough surface, which is considered to be a faithful reproduction for transmittance and reflectance. The Raman spectra and FDTD simulation results are in excellent agreement; not to be confused with metal local surface plasmon resonances (LSPRs). The Raman spectra peaks and hotspot are the results of the PDMS Si-O backbone. The PDMS substrate presented the diversity of the optical properties, which makes the substrate complementary to various optical applications.

  17. Modified polarimetric bidirectional reflectance distribution function with diffuse scattering: surface parameter estimation (United States)

    Zhan, Hanyu; Voelz, David G.


    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.

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

    International Nuclear Information System (INIS)

    Wuest, C.R.


    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

  19. Interaction of mineral surfaces with simple organic molecules by diffuse reflectance IR spectroscopy (DRIFT)

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Joan E.; Kelley, Michael J.


    Diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) was used to characterize multi-layers of lysine, glutamic acid and salicylic acid on -alumina and kaolinite surfaces. The results agreed well with those previously obtained by ATR-IR in aqueous media where available, indicating that DRIFT may be regarded as effectively an in-situ spectroscopy for these materials. In the case of salicylic acid adsorption onto γ-alumina, DRIFTS was used to identify monolayer coverage and to detect molecules down to coverage of 3% of a monolayer. The spectroscopic results as to coverage were confirmed by analysis of the solutions used for treatment. The spectra obtained allowed identification of changes in the bonding environment with increasing surface coverage. DRIFTS, offers several advantages in terms of materials, experimental technique and data treatment, motivating further investigations.

  20. Reconciling Electrical Properties of Titan's Surface Derived from Cassini RADAR Scatterometer and Radiometer Measurements (United States)

    Zebker, H. A.; Wye, L. C.; Janssen, M.; Paganelli, F.; Cassini RADAR Team


    We observe Titan, Saturn's largest moon, using active and passive microwave instruments carried on board the Cassini spacecraft. The 2.2-cm wavelength penetrates the thick atmosphere and provides surface measurements at resolutions from 10-200 km over much of the satellite's surface. The emissivity and reflectivity of surface features are generally anticorrelated, and both values are fairly high. Inversion of either set of data alone yields dielectric constants ranging from 1.5 to 3 or 4, consistent with an icy hydrocarbon or water ice composition. However, the dielectric constants retrieved from radiometric data alone are usually less than those inferred from backscatter measurements, a discrepancy consistent with similar analyses dating back to lunar observations in the 1960's. Here we seek to reconcile Titan's reflectivity and emissivity observations using a single physical model of the surface. Our approach is to calculate the energy scattered by Titan's surface and near subsurface, with the remainder absorbed. In equilibrium the absorption equals the emission, so that both the reflectivity and emissivity are described by the model. We use a form of the Kirchhoff model for modeling surface scatter, and a model based on weak localization of light for the volume scatter. With this model we present dielectric constant and surface roughness parameters that match both sets of Cassini RADAR observations over limited regions on Titan's surface, helping to constrain the composition and roughness of the surface. Most regions display electrical properties consistent with solid surfaces, however some of the darker "lake-like" features at higher latitudes can be modeled as either solid or liquid materials. The ambiguity arises from the limited set of observational angles available.

  1. Improved Near-surface Velocity Models from Waveform Tomography Applied to Vibroseis MCS Reflection Data (United States)

    Smithyman, B.; Clowes, R. M.


    Multichannel vibroseis reflection surveys are prevalent in the land exploration seismic industry because of benefits in speed and cost, along with reduced environmental impact when compared to explosive sources. Since the downgoing energy must travel through the shallow subsurface, an improved model of near-surface velocity can in theory substantially improve the resolution of deeper reflections. We describe techniques aimed at allowing the use of vibroseis data for long-offset refraction processing of first-arrival traveltimes and waveforms. Refraction processing of surface vibroseis data is typically limited to near-offset refraction statics. Velocity models of the shallow subsurface can be built to facilitate CDP stacking and migration, but these models are typically coarse and of limited use for interpretation. Waveform tomography combines inversion of first-arrival traveltime data with full waveform inversion of densely-sampled refracted arrivals. Since inversion of the waveform amplitude and phase is not limited by the ray-theory approximation, identification of low-velocity zones and small scattering targets is possible. Incorporating a wide range of offsets is critical for a more complete characterization of the near-surface. Because of the use of a non-linear frequency-domain approach to the solution of this inverse problem, low data frequencies are important in comparison with conventional reflection processing. Through the use of waveform tomography, we plan to build useful, detailed near-surface velocity models for both the reflection work flow and direct interpretation. Several difficulties exist in first-arrival analysis and waveform inversion of vibroseis data. The mixed-phase vibroseis source signature exhibits variations in phase with offset that are difficult to quantify without detailed a priori knowledge of the near-surface. This causes difficulties with picking and initial model building, which is critical for non-linear waveform inversion. A

  2. Estimation of Melt Ponds over Arctic Sea Ice using MODIS Surface Reflectance Data (United States)

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


    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

  3. Collection and corrections of oblique multiangle hyperspectral bidirectional reflectance imagery of the water surface (United States)

    Bostater, Charles R.; Oney, Taylor S.


    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.

  4. Spectrally adjusted surface reflectance and its dependence with NDVI for Landsat and Sentinel 2 (United States)

    Villaescusa, J. L.; Franch, B.; Roger, J. C.; Vermote, E.; Justice, C. O.


    Cross-calibration between sensors is necessary to bring measurements to a common radiometric scale; it allows a more complete monitoring of land surface processes and enhances data continuity and harmonization. However, differences in the Relative Spectral Response (RSR) of sensors generate uncertainties in the process (Teillet et al., 2004). For this reason, compensating for these differences is of great importance and can be achieved by using a spectral band adjustment factor (SBAF), which establishes a relationship between two spectrally adjusted bands. Nonetheless, this relationship has been shown to depend greatly on the surface's NDVI (Trishchenko et al., 2002) and therefore needs to be corrected. In this work, we use the Sentinel 2 and Landsat sensor's RSRs for both the Red and NIR bands to find the most accurate metric towards performing said relationship, and use surface reflectance spectral libraries with a wide variety of classes that include NDVI values ranging from -0.1 to 1 to analyze its dependence. We compute a quadratic fit of the metric used vs the surface's NDVI and propose an adjusted correction equation dependent on the NDVI value for both bands of all Landsat and Sentinel 2 sensors. Key words: Radiometric calibration, RSR, Spectral Adjustment, Landsat, Sentinel 2.

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

    Directory of Open Access Journals (Sweden)

    A. Ehrlich


    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.

  6. Reference-free total reflection X-ray fluorescence analysis of semiconductor surfaces with synchrotron radiation. (United States)

    Beckhoff, Burkhard; Fliegauf, Rolf; Kolbe, Michael; Müller, Matthias; Weser, Jan; Ulm, Gerhard


    Total reflection X-ray fluorescence (TXRF) analysis is a well-established method to monitor lowest level contamination on semiconductor surfaces. Even light elements on a wafer surface can be excited effectively when using high-flux synchrotron radiation in the soft X-ray range. To meet current industrial requirements in nondestructive semiconductor analysis, the Physikalisch-Technische Bundesanstalt (PTB) operates dedicated instrumentation for analyzing light element contamination on wafer pieces as well as on 200- and 300-mm silicon wafer surfaces. This instrumentation is also suited for grazing incidence X-ray fluorescence analysis and conventional energy-dispersive X-ray fluorescence analysis of buried and surface nanolayered structures, respectively. The most prominent features are a high-vacuum load-lock combined with an equipment front end module and a UHV irradiation chamber with an electrostatic chuck mounted on an eight-axis manipulator. Here, the entire surface of a 200- or a 300-mm wafer can be scanned by monochromatized radiation provided by the plane grating monochromator beamline for undulator radiation in the PTB laboratory at the electron storage ring BESSY II. This beamline provides high spectral purity and high photon flux in the range of 0.078-1.86 keV. In addition, absolutely calibrated photodiodes and Si(Li) detectors are used to monitor the exciting radiant power respectively the fluorescence radiation. Furthermore, the footprint of the excitation radiation at the wafer surface is well-known due to beam profile recordings by a CCD during special operation conditions at BESSY II that allow for drastically reduced electron beam currents. Thus, all the requirements of completely reference-free quantitation of TXRF analysis are fulfilled and are to be presented in the present work. The perspectives to arrange for reference-free quantitation using X-ray tube-based, table-top TXRF analysis are also addressed.

  7. Investigation of the surface adsorption and biotribological properties of mucins

    DEFF Research Database (Denmark)

    Madsen, Jan Busk

    to a surface. However, in other instances the inverse properties are desirable. Mucins are found on epithelial surfaces throughout the body and are a key component of the mucus barrier. Here, they facilitate friction reduction, thus lowering the impact of physical abrasions, but they also act as a physical...... and their aqueous lubrication properties have led to them being proposed as possible biocompatible lubricants. In this thesis, we investigate the biotribological properties of two commercially available mucins on the soft, elastomeric and hydrophobic surface of PDMS under different conditions. Due to the presence...... of a significant amount of non-mucin biomolecules in the commercial mucins, a mild single column protein purification protocol was established. In the mucin biotribology community, many employ the mucins either “as received” or after dialysis. It was therefore investigated how the established purification process...

  8. Effective modification of particle surface properties using ultrasonic water mist

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki


    The goal of the present study was to design a new technique to modify particle surface properties and, through that, to improve flowability of poorly flowing drug thiamine hydrochloride and pharmaceutical sugar lactose monohydrate of two different grades. The powdered particles were supplied...... properties. It was found that rapid exposition of pharmaceutical materials by water mist resulted in the improvement of powder technical properties. The evident changes in flowability of coarser lactose were obviously due to smoothing of particle surface and decreasing in the level of fines with very slight...... increment in particle size. The changes in thiamine powder flow were mainly due to narrowing in particle size distribution where the tendency for better flow of finer lactose was related to surface and size modifications. The aqueous mist application did not cause any alteration of the crystal structures...

  9. Relating Silica Scaling in Reverse Osmosis to Membrane Surface Properties. (United States)

    Tong, Tiezheng; Zhao, Song; Boo, Chanhee; Hashmi, Sara M; Elimelech, Menachem


    We investigated the relationship between membrane surface properties and silica scaling in reverse osmosis (RO). The effects of membrane hydrophilicity, free energy for heterogeneous nucleation, and surface charge on silica scaling were examined by comparing thin-film composite polyamide membranes grafted with a variety of polymers. Results show that the rate of silica scaling was independent of both membrane hydrophilicity and free energy for heterogeneous nucleation. In contrast, membrane surface charge demonstrated a strong correlation with the extent of silica scaling (R 2 > 0.95, p scaling, whereas a more negative membrane surface charge led to reduced scaling. This observation suggests that deposition of negatively charged silica species on the membrane surface plays a critical role in silica scale formation. Our findings provide fundamental insights into the mechanisms governing silica scaling in reverse osmosis and highlight the potential of membrane surface modification as a strategy to reduce silica scaling.

  10. Determination of Surface Properties of Liquid Transition Metals

    International Nuclear Information System (INIS)

    Korkmaz, S. D.


    Certain surface properties of liquid simple metals are reported. Using the expression derived by Gosh and coworkers we investigated the surface entropy of liquid transition metals namely Fe, Co and Ni. We have also computed surface tensions of the metals concerned. The pair distribution functions are calculated from the solution of Ornstein-Zernike integral equation with Rogers-Young closure using the individual version of the electron-ion potential proposed by Fioalhais and coworkers which was originally developed for solid state. The predicted values of surface tension and surface entropy are in very good agreement with available experimental data. The present study results show that the expression derived by Gosh and coworkers is very useful for the surface entropy by using Fioalhais pseudopotential and Rogers-Young closure

  11. LBA-ECO CD-34 Hyperion 30-m Surface Reflectance, Amazon Basin: 2002-2005 (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains 20 multispectral surface reflectance images collected by the EO-1 satellite Hyperion sensor at 30-m resolution and covering the...

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

  13. CLPX-Satellite: EO-1 Hyperion Surface Reflectance, Snow-Covered Area, and Grain Size, Version 1 (United States)

    National Aeronautics and Space Administration — This data set consists of apparent surface reflectance, subpixel snow-covered area, and grain size collected from the Hyperion hyperspectral imager. The Hyperion...

  14. MODIS/Aqua Surface Reflectance Daily L2G Global 1km and 500m SIN Grid V006 (United States)

    National Aeronautics and Space Administration — The MYD09GA Version 6 product provides an estimate of the surface spectral reflectance of AQUA MODIS Bands 1-7 corrected for atmospheric conditions such as gasses,...

  15. MODIS/Terra Surface Reflectance Daily L2G Global 1km and 500m SIN Grid V006 (United States)

    National Aeronautics and Space Administration — The MOD09GA Version 6 product provides an estimate of the surface spectral reflectance of Terra MODIS Bands 1-7 corrected for atmospheric conditions such as gasses,...

  16. The surface properties of biopolymer-coated fruit: A review

    Directory of Open Access Journals (Sweden)

    Diana Cristina Moncayo Martinez


    Full Text Available Environmental conservation concerns have led to research and development regarding biodegradable materials from biopolymers, leading to new formulations for edible films and coatings for preserving the quality of fresh fruit and vegetables. Determining fruit skin surface properties for a given coating solution has led to predicting coating efficiency. Wetting was studied by considering spreading, adhesion and cohesion and measuring the contact angle, thus optimising the coating formulation in terms of biopolymer, plasticiser, surfactant, antimicrobial and antioxidant concentration. This work reviews the equations for determining fruit surface properties by using polar and dispersive interaction calculations and by determining the contact angle.

  17. Plasma surface reflectance spectroscopy for non-invasive and continuous monitoring of extracellular component of blood (United States)

    Sakota, Daisuke; Takatani, Setsuo


    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.

  18. A prototype for automation of land-cover products from Landsat Surface Reflectance Data Records (United States)

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


    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.

  19. Properties of water surface discharge at different pulse repetition rates

    International Nuclear Information System (INIS)

    Ruma,; Yoshihara, K.; Hosseini, S. H. R.; Sakugawa, T.; Akiyama, H.; Akiyama, M.; Lukeš, P.


    The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H 2 O 2 ) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H 2 O 2 and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

  20. Influence of surface roughness on the friction property of textured surface


    Yuankai Zhou; Hua Zhu; Wenqian Zhang; Xue Zuo; Yan Li; Jianhua Yang


    In contrast with dimple textures, surface roughness is a texture at the micro-scale, essentially which will influence the load-bearing capacity of lubricant film. The numerical simulation was carried out to investigate the influence of surface roughness on friction property of textured surface. The lubricant film pressure was obtained using the method of computational fluid dynamics according to geometric model of round dimple, and the renormalization-group k–ε turbulent model was adopted in ...

  1. 30-m Land Surface Albedo by Integrating Landsat directional reflectance and MODIS anisotropic information (United States)

    Shuai, Y.; Masek, J. G.; Gao, F.; Schaaf, C.; Williams, C. A.; Wang, Z.


    Land surface albedo as a key physical variable determining the solar energy absorbed by the land surface, and can affect climate through ecosystem feedback processes. Some studies have highlighted that positive radiative forcing (warming) induced by increased forest cover and decreased albedo in temperate and boreal forest regions could offset the negative forcing expected from carbon sequestration (Betts 2000). However, these studies have not used data at the spatial resolution of human land dynamics (e.g. 30m Landsat resolution). Therefore, there is a need for improved estimates of land surface albedo at high resolution to fully understand the role of land cover change in climate forcing and carbon cycle. Following our initial "concurrent" approach applied to Landsat data acquired during the post-2000 MODIS era (Shuai et al.2011), we have developed a "pre-MODIS era" approach to generate 30-meter albedos using Landsat surface directional reflectance (1970s-2000) and Look-Up-Tables (LUT) of anisotropy information extracted from MODIS BRDF data. We use a NLCD (National Land Cover Dataset)-class-based LUT for non-disturbed land cover. Disturbed forest patches are identified from the Monitoring Trends in Burn Severity (MTBS) and North American Forest Dynamics (NAFD) datasets. For each category, high quality MODIS BRDF parameters (MCD43A1 product) are retrieved and used to populate the LUT. Each entry in the LUT reflects a unique combination of land cover type, disturbance age and type, season/month, and sensor bands. The initial BRDF LUT generated for the Pacific Northwest of the United States exhibits various BRDF evolution trajectories for disturbed classes, including different recovery trajectories for fire and non-fire disturbance. The albedo-to-nadir-ratio method (Shuai et al., 2011) is applied to the BRDF LUT to calculate spectral albedos, followed by a narrow-to-broadband conversion (Liang 2000) to generate broad-band shortwave albedo. Our preliminary

  2. Analysis of Visible/SWIR surface reflectance ratios for aerosol retrievals from satellite in Mexico City urban area

    Directory of Open Access Journals (Sweden)

    A. D. de Almeida Castanho


    Full Text Available The surface reflectance ratio between the visible (VIS and shortwave infrared (SWIR radiation is an important quantity for the retrieval of the aerosol optical depth (τa from the MODIS sensor data. Based on empirically determined VIS/SWIR ratios, MODIS τa retrieval uses the surface reflectance in the SWIR band (2.1 µm, where the interaction between solar radiation and the aerosol layer is small, to predict the visible reflectances in the blue (0.47 µm and red (0.66 µm bands. Therefore, accurate knowledge of the VIS/SWIR ratio is essential for achieving accurate retrieval of aerosol optical depth from MODIS. We analyzed the surface reflectance over some distinct surface covers in and around the Mexico City metropolitan area (MCMA using MODIS radiances at 0.66 µm and 2.1 µm. The analysis was performed at 1.5 km×1.5 km spatial resolution. Also, ground-based AERONET sun-photometer data acquired in Mexico City from 2002 to 2005 were analyzed for aerosol depth and other aerosol optical properties. In addition, a network of hand-held sun-photometers deployed in Mexico City, as part of the MCMA-2006 Study during the MILAGRO Campaign, provided an unprecedented measurement of τa in 5 different sites well distributed in the city. We found that the average RED/SWIR ratio representative of the urbanized sites analyzed is 0.73±0.06 for scattering angles <140° and goes up to 0.77±0.06 for higher ones. The average ratio for non-urban sites was significantly lower (approximately 0.55. In fact, this ratio strongly depends on differences in urbanization levels (i.e. relative urban to vegetation proportions and types of surface materials. The aerosol optical depth retrieved from MODIS radiances at a spatial resolution of 1.5 km×1.5 km and averaged within 10×10 km boxes were compared with collocated 1-h τa averaged from sun-photometer measurements. The use of the new RED

  3. 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)


    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.)

  4. Attenuated total reflectance Fourier-transform infrared spectroscopy of carboxylic acids adsorbed onto mineral surfaces (United States)

    Kubicki, J. D.; Schroeter, L. M.; Itoh, M. J.; Nguyen, B. N.; Apitz, S. E.


    A suite of naturally-occurring carboxylic acids (acetic, oxalic, citric, benzoic, salicylic and phthalic) and their corresponding sodium salts were adsorbed onto a set of common mineral substrates (quartz, albite, illite, kaolinite and montmorillonite) in batch slurry experiments. Solution pH's of approximately 3 and 6 were used to examine the effects of pH on sorption mechanisms. Attenuated total reflectance Fourier-transform infrared (ATR FTIR) spectroscopy was employed to obtain vibrational frequencies of the organic ligands on the mineral surfaces and in solution. UV/visible spectroscopy on supernatant solutions was also employed to confirm that adsorption from solution had taken place for benzoic, salicylic and phthalic acids. Molecular orbital calculations were used to model possible surface complexes and interpret the experimental spectra. In general, the tectosilicates, quartz and albite feldspar, did not chemisorb (i.e., strong, inner-sphere adsorption) the carboxylate anions in sufficient amounts to produce infrared spectra of the organics after rinsing in distilled water. The clays (illite, kaolinite and montmorillonite) each exhibited similar ATR FTIR spectra. However, the illite sample used in this study reacted to form strong surface and aqueous complexes with salicylic acid before being treated to remove free Fe-hydroxides. Chemisorption of carboxylic acids onto clays is shown to be limited without the presence of Fe-hydroxides within the clay matrix.

  5. Reversible Surface Properties of Polybenzoxazine/Silica Nanocomposites Thin Films

    Directory of Open Access Journals (Sweden)

    Wei-Chen Su


    Full Text Available We report the reversible surface properties (hydrophilicity, hydrophobicity of a polybenzoxazine (PBZ thin film through simple application of alternating UV illumination and thermal treatment. The fraction of intermolecularly hydrogen bonded O–H⋯O=C units in the PBZ film increased after UV exposure, inducing a hydrophilic surface; the surface recovered its hydrophobicity after heating, due to greater O–H⋯N intramolecular hydrogen bonding. Taking advantage of these phenomena, we prepared a PBZ/silica nanocomposite coating through two simple steps; this material exhibited reversible transitions from superhydrophobicity to superhydrophilicity upon sequential UV irradiation and thermal treatment.

  6. Enhancement of surface properties for coal beneficiation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chander, S.; Aplan, F.F.


    This report will focus on means of pyrite removal from coal using surface-based coal cleaning technologies. The major subjects being addressed in this study are the natural and modulated surface properties of coal and pyrite and how they may best be utilized to facilitate their separation using advanced surface-based coal cleaning technology. Emphasis is based on modified flotation and oil agglomerative processes and the basic principles involved. The four areas being addressed are: (1) Collectorless flotation of pyrite; (2) Modulation of pyrite and coal hydrophobicity; (3) Emulsion processes and principles; (4) Evaluation of coal hydrophobicity.

  7. 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


    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 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.

  8. Laser alloying of aluminium to improve surface properties - MSSA 2010

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB


    Full Text Available Aluminium is vastly used in industry due to its low cost, light weight and excellent workability, but lacks in wear resistance and hardness. Laser alloying is used to improve the surface properties such as hardness by modifying the composition...

  9. 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


    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.

  10. A sea surface reflectance model for (A)ATSR, and application to aerosol retrievals (United States)

    Sayer, A. M.; Thomas, G. E.; Grainger, R. G.


    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.

  11. Online Monitoring of Laser-Generated XUV Radiation Spectra by Surface Reflectivity Measurements with Particle Detectors

    Directory of Open Access Journals (Sweden)

    Andreas Hoffmann


    Full Text Available In this contribution, we present a wavelength-sensitive method for the detection of extreme ultraviolet (XUV photon energies between 30 eV and 120 eV. The method is based on 45° reflectivity from either a cesium iodide-coated or an uncoated metal surface, which directs the XUV beam onto an electron or ion detector and its signal is used to monitor the XUV beam. The benefits of our approach are a spectrally sensitive diagnosis of the XUV radiation at the interaction place of time-resolved XUV experiments and the detection of infrared leak light though metal filters in high-harmonic generation (HHG experiments. Both features were tested using spectrally shaped XUV pulses from HHG in a capillary, and we have achieved excellent agreement with XUV spectrometer measurements and reflectivity calculations. Our obtained results are of interest for time-resolved XUV experiments presenting an additional diagnostic directly in the interaction region and for small footprint XUV beamline diagnostics.

  12. Mixed polymer conductors for control of microwave reflectivity surfaces. Volume I

    International Nuclear Information System (INIS)

    Despotakis, A.


    The preparation and characterisation of polyaniline-silver-polymer electrolyte composite materials are described and their potential application as large area surfaces with microwave reflection/transmission controlled by application of an electric field ('microwave shutters') is investigated. The component polymer electrolyte (largely polyether-silver salt) and the polyaniline-silver salt mixtures have been separately investigated using a range of spectroscopic, microscopic and electrical impedance techniques. The redox behaviour of polyaniline versus silver in various cells incorporating polymer electrolytes have been studied in both ambient and 'dry' nitrogen environments using cyclic voltammetry and square wave potentiometry. It is proposed that the redox behaviour in dry nitrogen conditions involves the formation of leucoemeraldine-Ag + complex. This promotes the spontaneous reduction of emeraldine salt to leucoemeraldine by silver metal in contrast to the equilibrium status of the system in ambient conditions. In ambient conditions, the emeraldine undergoes an acid-base transition in the presence of silver salt (with(out) elemental silver). Furthermore, X-ray analysis has revealed that it is possible to chemically generate elemental silver after mixing its silver salt with the emeraldine (either salt or base form) in ambient conditions. Discs of various polyaniline-silver-polymer electrolyte compositions have been reported. Significant and rapid changes in microwave reflectivities have been observed. The mechanisms of electrochemical changes within the composites have been discussed and a 'cascade' process for the propagation of the switching effect across the areas of the discs has been proposed. (author)

  13. Experimental Analysis of Grease Friction Properties on Sliding Textured Surfaces

    Directory of Open Access Journals (Sweden)

    Xijun Hua


    Full Text Available There is comprehensive work on the tribological properties and lubrication mechanisms of oil lubricant used on textured surfaces, however the use of grease lubrication on textured surfaces is rather new. This research article presents an experimental study of the frictional behaviours of grease lubricated sliding contact under mixed lubrication conditions. The influences of surface texture parameters on the frictional properties were investigated using a disc-on-ring tribometer. The results showed that the friction coefficient is largely dependent on texture parameters, with higher and lower texture density resulting in a higher friction coefficient at a fixed texture depth. The sample with texture density of 15% and texture depth of 19 μm exhibited the best friction properties in all experimental conditions because it can store more grease and trap wear debris. The reduction of friction is mainly attributable to the formation of a stable grease lubrication film composed of oil film, transfer film and deposited film, and the hydrodynamic pressure effect of the surface texture, which increases the mating gap and reduces the probability of asperity contact. This result will help in understanding the tribological behaviour of grease on a textured surface and in predicting the lubrication conditions of sliding bearings for better operation in any machinery.

  14. Spatial and temporal variability of soil temperature, moisture and surface soil properties (United States)

    Hajek, B. F.; Dane, J. H.


    The overall objectives of this research were to: (l) Relate in-situ measured soil-water content and temperature profiles to remotely sensed surface soil-water and temperature conditions; to model simultaneous heat and water movement for spatially and temporally changing soil conditions; (2) Determine the spatial and temporal variability of surface soil properties affecting emissivity, reflectance, and material and energy flux across the soil surface. This will include physical, chemical, and mineralogical characteristics of primary soil components and aggregate systems; and (3) Develop surface soil classes of naturally occurring and distributed soil property assemblages and group classes to be tested with respect to water content, emissivity and reflectivity. This document is a report of studies conducted during the period funded by NASA grants. The project was designed to be conducted over a five year period. Since funding was discontinued after three years, some of the research started was not completed. Additional publications are planned whenever funding can be obtained to finalize data analysis for both the arid and humid locations.

  15. Study of surface tension and surface properties of binary alcohol/n-alkyl acetate mixtures. (United States)

    Rafati, Amir Abbas; Ghasemian, Ensieh


    The Butler equation is employed to describe quantitatively the nature, properties, and compositions of surface layers in binary liquid mixtures. Bulk mole fraction, surface molar area, and surface tension of pure components are necessary inputs for this equation. In addition, the UNIFAC group contribution method is applied to account for the nonideality of the bulk liquid as well as that of the surface layer. The average relative error obtained from the comparison of experimental and calculated surface tension values for 12 binary systems is less than 1%. Therefore, the model has good accuracy in comparison with other predictive equations. In addition to finding more information about the surface structure of binary mixtures, surface mole fraction was calculated using relative Gibbs adsorption values and an extended Langmuir model (EL). The obtained results show a good consistency between two models employed, i.e., the Gibbs adsorption model and EL model, based on the UNIFAC method.

  16. Relationship between the velvet-like texture of flower petals and light reflection from epidermal cell surfaces. (United States)

    Zhang, Yang; Sun, Tianxun; Xie, Linan; Hayashi, Takahiro; Kawabata, Saneyuki; Li, Yuhua


    Texture such as velvet lustre contributes to the ornamental character of a flower, along with shape and colour. This study aims to clarify the relationship between the formation of the velvet lustre texture and the optical characteristics of light reflection from irradiated surfaces of velvety and non-velvety petals from 30 cultivars or varieties of ornamental plants representing 19 species from various families. The angle of incident light from the petal surface was set at 90°, 60° or 30°, then light reflection from the petal surfaces was observed using a digital microscope. The observed reflected light was composed of "exterior" reflected light (ERL), which is observed as sparkling white spots on the surface of the epidermal cells, and "interior" reflected light (IRL), which is reflected from inside the petal and determines the base colour of the petals. Velvety petals had two common characteristics: conical-papillate or domed epidermal cells and a dark colour. As the angle between the petal and the incident light decreased, the ERL spots took on a belt-like shape, and total ERL intensity became stronger. We concluded that the velvety texture is derived from characteristic ERL rays coupled with dark IRL. The long sloping surface of the epidermal cells contributes to the higher ERL intensity as petals are observed from more horizontal angles, causing characteristic reverse shading effects on velvety petals.

  17. Membranes with Surface-Enhanced Antifouling Properties for Water Purification (United States)

    Shahkaramipour, Nima; Tran, Thien N.; Ramanan, Sankara; Lin, Haiqing


    Membrane technology has emerged as an attractive approach for water purification, while mitigation of fouling is key to lower membrane operating costs. This article reviews various materials with antifouling properties that can be coated or grafted onto the membrane surface to improve the antifouling properties of the membranes and thus, retain high water permeance. These materials can be separated into three categories, hydrophilic materials, such as poly(ethylene glycol), polydopamine and zwitterions, hydrophobic materials, such as fluoropolymers, and amphiphilic materials. The states of water in these materials and the mechanisms for the antifouling properties are discussed. The corresponding approaches to coat or graft these materials on the membrane surface are reviewed, and the materials with promising performance are highlighted. PMID:28273869

  18. The practice of reflection in the russian goodwill when buying enterprises as a property complex

    Directory of Open Access Journals (Sweden)

    O. A. Ovchinnikova


    Full Text Available When buying enterprises as a property complex, firm-the buyer can pay for it as excess cost of the acquired entity on its balance sheet, and an amount less than the value of the assets on the balance sheet of the acquiree. Based on the requirements of the Russian legislation, in the account of the buyer acquires an intangible asset that distinguishes the Russian from the international practice. International financial reporting standards do not recognize goodwill an intangible asset of the buyer enterprise. Therefore, it is necessary to specify the Russian practice of accounting transactions in the purchase of enterprises as property complex. The article presents a definition of the property complex, based on the requirements of the Civil Code of the Russian Federation, highlighted the stages of transfer of the property complex of the specified accounting documents that must be decorated, the analysis of the approaches of domestic and foreign authors to the recognition and measurement of goodwill, studied the specificity of the requirements of the Russian normative-legislative acts to the category “goodwill”, “intangible asset”. Based on the requirements of the Russian legislation, a positive goodwill is recognized in intangible asset (goodwill, in contrast to the negative goodwill (badwill, which immediately applies on other income of the organisation – the buyer of the enterprise – a property complex. On the positive business reputation, then the requirements of the Russian legislation, a positive goodwill is recognized intangible asset. In this paper, the authors proposed a model accounting for the purchase of enterprise as property complex as a result of which the acquisition price of an enterprise as a property complex exceeds its carrying amount of the assessment, therefore, in accounting, the buyer acquires an intangible asset in the form of a positive business reputation, compiled and substantiated recommended to reflect this

  19. Mechanical and tribological properties of ion beam-processed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kodali, Padma [Univ. of Maryland, College Park, MD (United States)


    The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness.

  20. Mechanical and tribological properties of ion beam-processed surfaces

    International Nuclear Information System (INIS)

    Kodali, P.


    The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness

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

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


    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. Reflectance properties of one-dimensional metal-dielectric ternary photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, G. N., E-mail: [Department of Physics, Amity Institute of Applied Sciences, AmityUniversity, Noida (U.P.) (India); Kumar, Narendra [Department of Physics (CASH), Modi University of Science and Technology, Lakshmangarh, Sikar, Rajsthan (India); Thapa, Khem B. [Department of Physics, U I E T, ChhatrapatiShahu Ji Maharaj University, Kanpur- (UP) (India); Ojha, S. P. [Department of Physics IIT, Banaras Hindu University (India)


    Metallic photonic crystal has a very important application in absorption enhancement in solar cells. It has been found that an ultra-thin metallic layer becomes transparent due to internal scattering of light through the each interface of the dielectric and metal surfaces. The metal has absorption due to their surface plasmon and the plasmon has important parameters for changing optical properties of the metal. We consider ternary metallic-dielectric photonic crystal (MDPC) for having large probabilities to change the optical properties of the MDPC and the photonic crystals may be changed by changing dimensionality, symmetry, lattice parameters, Filling fraction and effective refractive index refractive index contrast. In this present communication, we try to show that the photonic band gap in ternary metal-dielectric photonic crystal can be significantly enlarged when air dielectric constant is considered. All the theoretical analyses are made based on the transfer matrix method together with the Drude model of metal.

  3. Surface-defect induced modifications in the optical properties of α-MnO2 nanorods

    International Nuclear Information System (INIS)

    John, Reenu Elizabeth; Chandran, Anoop; Thomas, Marykutty; Jose, Joshy; George, K.C.


    Graphical abstract: - Highlights: • Alpha-MnO 2 nanorods are prepared by chemical method. • Difference in surface defect density is achieved. • Characterized using XRD, Rietveld, XPS, EDS, HR-TEM, BET, UV–vis absorption spectroscopy and PL spectroscopy. • Explains the bandstructure modification due to Jahn–Teller distortions using crystal field theory. • Modification in the intensity of optical emissions related to defect levels validates the concept of surface defect induced tuning of optical properties. - Abstract: The science of defect engineering via surface tuning opens a new route to modify the inherent properties of nanomaterials for advanced functional and practical applications. In this work, two independent synthesis methods (hydrothermal and co-precipitation) are adopted to fabricate α-MnO 2 nanorods with different defect structures so as to understand the effect of surface modifications on their optical properties. The crystal structure and morphology of samples are investigated with the aid of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Atomic composition calculated from energy dispersive spectroscopy (EDS) confirms non-stoichiometry of the samples. The surface properties and chemical environment are thoroughly studied using X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis. Bond angle variance and bond valence sum are determined to validate distortions in the basic MnO 6 octahedron. The surface studies indicate that the concentration of Jahn–Teller manganese (III) (Mn 3+ ) ion in the samples differ from each other which results in their distinct properties. Band structure modifications due to Jahn–Teller distortion are examined with the aid of ultraviolet–visible (UV) reflectance and photoluminescence (PL) studies. The dual peaks obtained in derivative spectrum conflict the current concept on the bandgap energy of MnO 2 . These studies suggest that

  4. [Corrosion resistant properties of different anodized microtopographies on titanium surfaces]. (United States)

    Fangjun, Huo; Li, Xie; Xingye, Tong; Yueting, Wang; Weihua, Guo; Weidong, Tian


    To investigate the corrosion resistant properties of titanium samples prepared by anodic oxidation with different surface morphologies. Pure titanium substrates were treated by anodic oxidation to obtain porous titanium films in micron, submicron, and micron-submicron scales. The surface morphologies, coating cross-sectional morphologies, crystalline structures, and surface roughness of these samples were characterized. Electrochemical technique was used to measure the corrosion potential (Ecorr), current density of corrosion (Icorr), and polarization resistance (Rp) of these samples in a simulated body fluid. Pure titanium could be modified to exhibit different surface morphologies by the anodic oxidation technique. The Tafel curve results showed that the technique can improve the corrosion resistance of pure titanium. Furthermore, the corrosion resistance varied with different surface morphologies. The submicron porous surface sample demonstrated the best corrosion resistance, with maximal Ecorr and Rp and minimal Icorr. Anodic oxidation technology can improve the corrosion resistance of pure titanium in a simulated body fluid. The submicron porous surface sample exhibited the best corrosion resistance because of its small surface area and thick barrier layer.

  5. Continuity of Reflectance Data between Landsat-7 ETM+ and Landsat-8 OLI, for Both Top-of-Atmosphere and Surface Reflectance: A Study in the Australian Landscape

    Directory of Open Access Journals (Sweden)

    Neil Flood


    Full Text Available The new Landsat-8 Operational Land Imager (OLI is intended to be broadly compatible with the previous Landsat-7 Enhanced Thematic Mapper Plus (ETM+. The spectral response of the OLI is slightly different to the ETM+, and so there may be slight differences in the reflectance measurements. Since the differences are a function not just of spectral responses, but also of the target pixels, there is a need to assess these differences in practice, using imagery from the area of interest. This paper presents a large scale study of the differences between ETM+ and OLI in the Australian landscape. The analysis is carried out in terms of both top-of-atmosphere and surface reflectance, and also in terms of biophysical parameters modelled from those respective reflectance spectra. The results show small differences between the sensors, which can be magnified by modelling to a biophysical parameter. It is also shown that a part of this difference appears to be systematic, and can be reliably removed by regression equations to predict ETM+ reflectance from OLI reflectance, before applying biophysical models. This is important when models have been fitted to historical field data coincident with ETM+ imagery. However, there will remain a small per-pixel difference which could be an unwanted source of variability.

  6. Investigation of magnetorheological elastomer surface properties by atomic force microscopy

    International Nuclear Information System (INIS)

    Iacobescu, G.E.; Balasoiu, M.; Bica, I.


    Magnetorheological elastomers consist of a natural or synthetic rubber matrix interspersed with micron-sized ferromagnetic particles. The magnetoelastic properties of such a composite are not merely a sum of elasticity of the polymer and stiffness and magnetic properties of the filler, but also the result of a complex synergy of several effects, relevant at different length scales and detectable by different techniques. In the present work we investigate the microstructures, the surface magnetic properties and the elastic properties of new isotropic and anisotropic magnetorheological elastomer prepared using silicone rubber and soft magnetic carbonyl iron microspheres. The measurements were performed by atomic force microscopy in the following modes: standard imaging-non-contact atomic force microscopy, magnetic force microscopy and nanoindentation. A comparative study for the samples with different particle concentrations and strength of magnetic field applied during the polymerization process is developed

  7. Surface and mechanical properties of polypropylene/clay nanocomposite

    Directory of Open Access Journals (Sweden)

    Dibaei Asl Husein


    Full Text Available Huge consumption of polypropylene in the industries like automotive motivates academic and industrial R&Ds to find new and excellent approaches to improve the mechanical properties of this polymer, which has no degradation effect on other required performance properties like impact resistance, controlled crystallinity, toughness and shrinkage. Nowadays, nanoparticles play a key role in improving the mechanical and surface properties of polypropylene. In this study, three compositions of "Polypropylene/nanoclay", containing 0%, 2% and 5% of nanoclay were prepared in internal mixer. For characterizing the nanoclay dispersion in polymer bulk, TEM and XRD tests were used. For scratch resistance test, scratch lines were created on the load of 900 grain on sheets and SEM images were taken and compared with neat PP scratch image. Crystallinity and mechanical behavior were studied. The results showed that mechanical properties and scratch resistance of the composites have been improved.

  8. Shear-wave seismic reflection imaging and impedance inversion for a near-surface point-bar (United States)

    Benton, N. W.; Morrison, M.; Lorenzo, J. M.; Odom, B.; Clift, P. D.; Olson, E.; Gostic, A.


    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

  9. Phase analysis for three-dimensional surface reconstruction of apples using structured-illumination reflectance imaging (United States)

    Lu, Yuzhen; Lu, Renfu


    Three-dimensional (3-D) shape information is valuable for fruit quality evaluation. This study was aimed at developing phase analysis techniques for reconstruction of the 3-D surface of fruit from the pattern images acquired by a structuredillumination reflectance imaging (SIRI) system. Phase-shifted sinusoidal patterns, distorted by the fruit geometry, were acquired and processed through phase demodulation, phase unwrapping and other post-processing procedures to obtain phase difference maps relative to the phase of a reference plane. The phase maps were then transformed into height profiles and 3-D shapes in a world coordinate system based on phase-to-height and in-plane calibrations. A reference plane-based approach, coupled with the curve fitting technique using polynomials of order 3 or higher, was utilized for phase-to-height calibrations, which achieved superior accuracies with the root-mean-squared errors (RMSEs) of 0.027- 0.033 mm for a height measurement range of 0-91 mm. The 3rd-order polynomial curve fitting technique was further tested on two reference blocks with known heights, resulting in relative errors of 3.75% and 4.16%. In-plane calibrations were performed by solving a linear system formed by a number of control points in a calibration object, which yielded a RMSE of 0.311 mm. Tests of the calibrated system for reconstructing the surface of apple samples showed that surface concavities (i.e., stem/calyx regions) could be easily discriminated from bruises from the phase difference maps, reconstructed height profiles and the 3-D shape of apples. This study has laid a foundation for using SIRI for 3-D shape measurement, and thus expanded the capability of the technique for quality evaluation of horticultural products. Further research is needed to utilize the phase analysis techniques for stem/calyx detection of apples, and optimize the phase demodulation and unwrapping algorithms for faster and more reliable detection.

  10. Thermal repellent properties of surface coating using silica (United States)

    Lee, Y. Y.; Halim, M. S.; Aminudin, E.; Guntor, N. A.


    Extensive land development in urban areas is completely altering the surface profile of human living environment. As cities growing rapidly, impervious building and paved surfaces are replacing the natural landscape. In the developing countries with tropical climate, large masses of building elements, such as brick wall and concrete members, absorb and store large amount of heat, which in turn radiate back to the surrounding air during the night time. This bubble of heat is known as urban heat island (UHI). The use of high albedo urban surfaces is an inexpensive measure that can reduce surrounded temperature. Thus, the main focus of this study is to investigate the ability of silica, SiO2, with high albedo value, to be used as a thermal-repelled surface coating for brick wall. Three different silica coatings were used, namely silicone resin, silicone wax and rain repellent and one exterior commercial paint (jota shield paint) that commercially available in the market were applied on small-scale brick wall models. An uncoated sample also had been fabricated as a control sample for comparison. These models were placed at the outdoor space for solar exposure. Outdoor environment measurement was carried out where the ambient temperature, surface temperature, relative humidity and UV reflectance were recorded. The effect of different type of surface coating on temperature variation of the surface brick wall and the thermal performance of coatings as potential of heat reduction for brick wall have been studied. Based on the results, model with silicone resin achieved the lowest surface temperature which indicated that SiO2 can be potentially used to reduce heat absorption on the brick wall and further retains indoor passive thermal comfortability.

  11. Dynamic Optoelectronic Properties in Perovskite Oxide Thin Films Measured with Ultrafast Transient Absorption & Reflectance Spectroscopy (United States)

    Smolin, Sergey Y.

    Ultrafast transient absorption and reflectance spectroscopy are foundational techniques for studying photoexcited carrier recombination mechanisms, lifetimes, and charge transfer rates. Because quantifying photoexcited carrier dynamics is central to the intelligent design and improvement of many solid state devices, these transient optical techniques have been applied to a wide range of semiconductors. However, despite their promise, interpretation of transient absorption and reflectance data is not always straightforward and often relies on assumptions of physical processes, especially with respect to the influence of heating. Studying the material space of perovskite oxides, the careful collection, interpretation, and analysis of ultrafast data is presented here as a guide for future research into novel semiconductors. Perovskite oxides are a class of transition metal oxides with the chemical structure ABO3. Although traditionally studied for their diverse physical, electronic, and magnetic properties, perovskite oxides have gained recent research attention as novel candidates for light harvesting applications. Indeed, strong tunable absorption, unique interfacial properties, and vast chemical flexibility make perovskite oxides a promising photoactive material system. However, there is limited research characterizing dynamic optoelectronic properties, such as recombination lifetimes, which are critical to know in the design of any light-harvesting device. In this thesis, ultrafast transient absorption and reflectance spectroscopy was used to understand these dynamic optoelectronic properties in highquality, thin (gap of LFO at 2.4 eV and at the higher energy absorption edge at 3.5 eV. Using a combination of temperature-dependent, variable-angle spectroscopic ellipsometry and time-resolved ultrafast optical spectroscopy on a type I heterostructure, we clarify thermal and electronic contributions to spectral transients in LaFeO3. Upon comparison to thermally

  12. Surface and subsurface hydrogen: adsorption properties on transition metals and near-surface alloys. (United States)

    Greeley, Jeff; Mavrikakis, Manos


    Periodic, self-consistent DFT-GGA calculations are used to study the thermochemical properties of both surface and subsurface atomic hydrogen on a variety of pure metals and near-surface alloys (NSAs). For surface hydrogen on pure metals, calculated site preferences, adsorption geometries, vibrational frequencies, and binding energies are reported and are found to be in good agreement with available experimental data. On NSAs, defined as alloys wherein a solute is present near the surface of a host metal in a composition different from the bulk composition, surface hydrogen generally binds more weakly than it binds to the pure-metal components composing the alloys. Some of the NSAs even possess the unusual property of binding hydrogen as weakly as the noble metals while, at the same time, dissociating H(2) much more easily. On both NSAs and pure metals, formation of surface hydrogen is generally exothermic with respect to H(2)(g). In contrast, formation of subsurface hydrogen is typically endothermic with respect to gas-phase H(2) (the only exception to this general statement is found for pure Pd). As with surface H, subsurface H typically binds more weakly to NSAs than to the corresponding pure-metal components of the alloys. The diffusion barrier for hydrogen from surface to subsurface sites, however, is usually lower on NSAs compared to the pure-metal components, suggesting that population of subsurface sites may occur more rapidly on NSAs.

  13. Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties

    Directory of Open Access Journals (Sweden)

    Variola F


    Full Text Available Fabio Variola,1,2 Sylvia Francis Zalzal,3 Annie Leduc,3 Jean Barbeau,3 Antonio Nanci31Faculty of Engineering, Department of Mechanical Engineering, 2Faculty of Science, Department of Physics, University of Ottawa, Ottawa, ON, 3Faculty of Dental Medicine, Université de Montréal, Montreal, QC, CanadaAbstract: Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explored. The main objective of this study was to test the effects of such surfaces on the adherence of two common bacteria and one yeast strain that are responsible for nosocomial infections in clinical settings and biomedical applications. In addition, because surface characteristics are known to affect bacterial adhesion, we further characterized the physicochemical properties of the mesoporous surfaces. Focused ion beam (FIB was used to generate ultrathin sections for elemental analysis by energy-dispersive X-ray spectroscopy (EDS, nanobeam electron diffraction (NBED, and high-angle annular dark field (HAADF scanning transmission electron microscopy (STEM imaging. The adherence of Staphylococcus aureus, Escherichia coli and Candida albicans onto titanium disks with mesoporous and polished surfaces was compared. Disks with the two surfaces side-by-side were also used for direct visual comparison. Qualitative and quantitative results from this study indicate that bacterial adhesion is significantly hindered by the mesoporous surface. In addition, we provide evidence that it alters structural parameters of C. albicans that determine its invasiveness potential, suggesting that microorganisms can sense and respond to the mesoporous surface. Our findings demonstrate the efficiency of a simple chemical oxidative treatment in generating nanotextured surfaces with antimicrobial capacity with potential applications in the implant manufacturing industry and hospital setting

  14. Microstructure and properties of cast iron after laser surface hardening

    Directory of Open Access Journals (Sweden)



    Full Text Available Laser surface hardening of cast iron is not trivial due to the material’s heterogeneity and coarse-grained microstructure, particularly in massive castings. Despite that, hardening of heavy moulds for automotive industry is in high demand. The present paper summarises the findings collected over several years of study of materials structure and surface properties. Phase transformations in the vicinity of graphite are described using examples from production of body parts in automotive industry. The description relates to formation of martensite and carbide-based phases, which leads to hardness values above 65 HRC and to excellent abrasion resistance.

  15. Updating Landsat time series of surface-reflectance composites and forest change products with new observations (United States)

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


    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

  16. Objective and Subjective Evaluation of Reflecting and Diffusing Surfaces in Auditoria (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

  17. Friction Properties of Surface-Fluorinated Carbon Nanotubes (United States)

    Wal, R. L. Vander; Miyoshi, K.; Street, K. W.; Tomasek, A. J.; Peng, H.; Liu, Y.; Margrave, J. L.; Khabashesku, V. N.


    Surface modification of the tubular or sphere-shaped carbon nanoparticles through chemical treatment, e.g., fluorination, is expected to significantly affect their friction properties. In this study, a direct fluorination of the graphene-built tubular (single-walled carbon nanotubes) structures has been carried out to obtain a series of fluorinated nanotubes (fluoronanotubes) with variable C(n)F (n =2-20) stoichiometries. The friction coefficients for fluoronanotubes, as well as pristine and chemically cut nanotubes, were found to reach values as low as 0.002-0.07, according to evaluation tests run in contact with sapphire in air of about 40% relative humidity on a ball-on-disk tribometer which provided an unidirectional sliding friction motion. These preliminary results demonstrate ultra-low friction properties and show a promise in applications of surface modified nanocarbons as a solid lubricant.

  18. Surface properties of Ti-6Al-4V alloy part I: Surface roughness and apparent surface free energy. (United States)

    Yan, Yingdi; Chibowski, Emil; Szcześ, Aleksandra


    Titanium (Ti) and its alloys are the most often used implants material in dental treatment and orthopedics. Topography and wettability of its surface play important role in film formation, protein adhesion, following osseointegration and even duration of inserted implant. In this paper, we prepared Ti-6Al-4V alloy samples using different smoothing and polishing materials as well the air plasma treatment, on which contact angles of water, formamide and diiodomethane were measured. Then the apparent surface free energy was calculated using four different approaches (CAH, LWAB, O-W and Neumann's Equation of State). From LWAB approach the components of surface free energy were obtained, which shed more light on the wetting properties of samples surface. The surface roughness of the prepared samples was investigated with the help of optical profilometer and AFM. It was interesting whether the surface roughness affects the apparent surface free energy. It was found that both polar interactions the electron donor parameter of the energy and the work of water adhesion increased with decreasing roughness of the surfaces. Moreover, short time plasma treatment (1min) caused decrease in the surface hydrophilic character, while longer time (10min) treatment caused significant increase in the polar interactions and the work of water adhesion. Although Ti-6Al-4V alloy has been investigated many times, to our knowledge, so far no paper has been published in which surface roughness and changes in the surface free energy of the alloy were compared in the quantitative way in such large extent. This novel approach deliver better knowledge about the surface properties of differently smoothed and polished samples which may be helpful to facilitate cell adhesion, proliferation and mineralization. Therefore the results obtained present also potentially practical meaning. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Magnetic Nanoparticles: Surface Effects and Properties Related to Biomedicine Applications


    Issa, Bashar; Obaidat, Ihab M.; Albiss, Borhan A.; Haik, Yousef


    Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways (e.g., chemical and physical) with controllable sizes enabling their comparison to biological organisms from cells (10–100 μm), viruses, genes, down to proteins (3–50 nm). The opti...

  20. A far ultraviolet spectroscopic study of the reflectance, luminescence and electronic properties of SrMgF4 single crystals

    International Nuclear Information System (INIS)

    Ogorodnikov, I.N.; Pustovarov, V.A.; Omelkov, S.I.; Isaenko, L.I.; Yelisseyev, A.P.; Goloshumova, A.A.; Lobanov, S.I.


    The electronic properties of single crystals of SrMgF 4 have been determined using low-temperature (10–293 K) time-resolved vacuum ultraviolet synchrotron radiation spectroscopy, far ultraviolet (3.7–36 eV) reflectance spectra and calculations for the spectra of optical functions. The bandgap of investigated compound was found at E g =12.55eV, the energy threshold for creation of the unrelaxed excitons at E n=1 =11.37eV, and the low-energy fundamental absorption edge at 10.3 eV. Two groups of photoluminescence (PL) bands have been identified: the exciton-type emissions at 2.6–3.3 and 3.3–4.2 eV and defect-related emissions at 1.8–2.6 and 4.2–5.5 eV. It was shown that PL excitation (PLE) for the exciton-type emission bands occurs mainly at the low-energy tail of the fundamental absorption of the crystal with a maximum at 10.7 eV. At excitation energies above E g the energy transfer from the host lattice to the PL emission centers is inefficient. The paper discusses the origin of the excitonic-type PLE spectra taking into account the results of modeling the PLE spectra shape in the framework of a simple diffusion theory and surface energy losses. -- Highlights: • Far-ultraviolet reflection spectra of SrMgF 4 were studied. • Photoluminescence (PL) emission and PL excitation spectra were studied. • Optical function spectra were calculated on the basis of experimental data. • Electronic structure properties of undoped SrMgF 4 crystals were determined

  1. Electrokinetic Properties of TiO2 Nanotubular Surfaces (United States)

    Lorenzetti, Martina; Gongadze, Ekaterina; Kulkarni, Mukta; Junkar, Ita; Iglič, Aleš


    Surface charge is one of the most significant properties for the characterisation of a biomaterial, being a key parameter in the interaction of the body implant with the surrounding living tissues. The present study concerns the systematic assessment of the surface charge of electrochemically anodized TiO2 nanotubular surfaces, proposed as coating material for Ti body implants. Biologically relevant electrolytes (NaCl, PBS, cell medium) were chosen to simulate the physiological conditions. The measurements were accomplished as titration curves at low electrolytic concentration (10-3 M) and as single points at fixed pH but at various electrolytic concentrations (up to 0.1 M). The results showed that all the surfaces were negatively charged at physiological pH. However, the zeta potential values were dependent on the electrolytic conditions (electrolyte ion concentration, multivalence of the electrolyte ions, etc.) and on the surface characteristics (nanotubes top diameter, average porosity, exposed surface area, wettability, affinity to specific ions, etc.). Accordingly, various explanations were proposed to support the different experimental data among the surfaces. Theoretical model of electric double layer which takes into account the asymmetric finite size of ions in electrolyte and orientational ordering of water dipoles was modified according to our specific system in order to interpret the experimental data. Experimental results were in agreement with the theoretical predictions. Overall, our results contribute to enrich the state-of-art on the characterisation of nanostructured implant surfaces at the bio-interface, especially in case of topographically porous and rough surfaces.

  2. Specular and non-specular X-ray reflection from a single-crystal molybdenum mirror surface

    CERN Document Server

    Mizusawa, M


    The surface morphology of a super-polished mirror of single-crystal molybdenum has been studied by grazing-incidence X-ray reflection. It yields a rather high specular reflectivity (82.0%) for 16.0 keV X-rays below the critical angle. The data suggest that the mirror has a small roughness (0.7 nm rms) unlike other metal mirrors, but, on the other hand, strongly damaged layers (6.35 nm in total) exist at the near surface. It has been also found that the surface has a large correlation length (>3 mu m) and a small Hurst parameter (0.2-0.3) from the non-specular reflection.

  3. Surface, structural and tensile properties of proton beam irradiated zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Rafique, Mohsin; Chae, San; Kim, Yong-Soo, E-mail:


    This paper reports the surface, structural and tensile properties of proton beam irradiated pure zirconium (99.8%). The Zr samples were irradiated by 3.5 MeV protons using MC-50 cyclotron accelerator at different doses ranging from 1 × 10{sup 13} to 1 × 10{sup 16} protons/cm{sup 2}. Both un-irradiated and irradiated samples were characterized using Field Emission Scanning Electron Microscope (FESEM), X-ray Diffraction (XRD) and Universal Testing Machine (UTM). The average surface roughness of the specimens was determined by using Nanotech WSxM 5.0 develop 7.0 software. The FESEM results revealed the formation of bubbles, cracks and black spots on the samples’ surface at different doses whereas the XRD results indicated the presence of residual stresses in the irradiated specimens. Williamson–Hall analysis of the diffraction peaks was carried out to investigate changes in crystallite size and lattice strain in the irradiated specimens. The tensile properties such as the yield stress, ultimate tensile stress and percentage elongation exhibited a decreasing trend after irradiation in general, however, an inconsistent behavior was observed in their dependence on proton dose. The changes in tensile properties of Zr were associated with the production of radiation-induced defects including bubbles, cracks, precipitates and simultaneous recovery by the thermal energy generated with the increase of irradiation dose.

  4. Surface, structural and tensile properties of proton beam irradiated zirconium (United States)

    Rafique, Mohsin; Chae, San; Kim, Yong-Soo


    This paper reports the surface, structural and tensile properties of proton beam irradiated pure zirconium (99.8%). The Zr samples were irradiated by 3.5 MeV protons using MC-50 cyclotron accelerator at different doses ranging from 1 × 1013 to 1 × 1016 protons/cm2. Both un-irradiated and irradiated samples were characterized using Field Emission Scanning Electron Microscope (FESEM), X-ray Diffraction (XRD) and Universal Testing Machine (UTM). The average surface roughness of the specimens was determined by using Nanotech WSxM 5.0 develop 7.0 software. The FESEM results revealed the formation of bubbles, cracks and black spots on the samples' surface at different doses whereas the XRD results indicated the presence of residual stresses in the irradiated specimens. Williamson-Hall analysis of the diffraction peaks was carried out to investigate changes in crystallite size and lattice strain in the irradiated specimens. The tensile properties such as the yield stress, ultimate tensile stress and percentage elongation exhibited a decreasing trend after irradiation in general, however, an inconsistent behavior was observed in their dependence on proton dose. The changes in tensile properties of Zr were associated with the production of radiation-induced defects including bubbles, cracks, precipitates and simultaneous recovery by the thermal energy generated with the increase of irradiation dose.

  5. [Light reflection zone on the incisors' surface--a new parameter for smile esthetics evaluation]. (United States)

    Brezniak, N; Wasserstein, A; Shmuli, T


    The light reflection zone (LRZ) is a bright white dot or area that appears on the surface of the maxillary central incisors and/or the gingiva of the front teeth, visible in intra-oral and smile extra-oral photographs. Previously, a positive correlation between the location of the LRZ as observed in intra-oral frontal photographs and the inclination of the upper central incisors as measured on lateral headfims was found. The purpose of this study was to find whether this LRZ location can serve as a new parameter influencing the level of smile esthetics. Twelve pairs of facial photographs, including 10 of ordinary smiling persons and 2 of smiling models, were presented to 138 participants. The only difference between each pair was the location of the LRZ that was moved, compared to the original photograph, gingivally or incisally respectively, using Photoshop (Adobe). Each participant was asked to mark whether he/she noticed a difference between the 2 pictures, and if so, to score the nicer smile. Data analysis was carried out using Chi square test and Fisher's exact test (SPSS v17). The results showed that most of the participants did not recognize the differences between the pairs however, when differences were recognized, most of the participants pointed on the smile where the LRZ was located gingivally as the nicer one. This result was with statistical significance for the 2 models (p < 0.05), In conclusion, the LRZ is a new, yet unrecognized, parameter that can serve as a tool for the diagnosis of esthetic smile. The general population defines a nicer smile when the LRZ is located in the gingival area of the upper central incisors' surface rather than the incisal third. The LRZ should probably be studied not only in Orthodontics but also in other branches of dentistry.

  6. Microstructure and surface properties of fibrous and ground cellulosic substrates. (United States)

    Csiszár, Emília; Fekete, Erika


    Cotton and linen fibers were ground in a ball-mill, and the effect of grinding on the microstructure and surface properties of the fibers was determined by combining a couple of simple tests with powerful techniques of surface and structure analysis. Results clearly proved that the effect of grinding on cotton fiber was much less severe than on linen. For both fibers, the degree of polymerization reduced (by 14.5% and 30.5% for cotton and linen, respectively) with a simultaneous increase in copper number. The increased water sorption capacity of the ground substrates was in good agreement with the X-ray results, which proved a less perfect crystalline structure in the ground samples. Data from XPS and SEM-EDS methods revealed that the concentration of oxygen atoms (bonded especially in acetal and/or carbonyl groups) on the ground surfaces increased significantly, resulting in an increase in oxygen/carbon atomic ratio (XPS data: from 0.11 to 0.14 and from 0.16 to 0.29 for cotton and linen, respectively). Although grinding created new surfaces rich in O atoms, the probable higher energy of the surface could not be measured by IGC, most likely due to the limited adsorption of the n-alkane probes on the less perfect crystalline surfaces. © 2011 American Chemical Society

  7. Effect of Surface Treatment on the Properties of Wool Fabric (United States)

    Kan, C. W.; Yuen, C. W. M.; Chan, C. K.; Lau, M. P.

    Wool fiber is commonly used in textile industry, however, it has some technical problems which affect the quality and performance of the finished products such as felting shrinkage, handle, lustre, pilling, and dyeability. These problems may be attributed mainly in the presence of wool scales on the fiber surface. Recently, chemical treatments such as oxidation and reduction are the commonly used descaling methods in the industry. However, as a result of the pollution caused by various chemical treatments, physical treatment such as low temperature plasma (LTP) treatment has been introduced recently because it is similarly capable of achieving a comparable descaling effect. Most of the discussions on the applications of LTP treatment on wool fiber were focused on applying this technique for improving the surface wettability and shrink resistance. Meanwhile, little discussion has been made on the mechanical properties, thermal properties, and the air permeability. In this paper, wool fabric was treated with LTP treatment with the use of a non-polymerizing gas, namely oxygen. After the LTP treatment, the fabrics low-stress mechanical properties, air permeability, and thermal properties were evaluated and discussed.


    Rao, Archana N.; Grainger, David W.


    Both clinical and analytical metrics produced by microarray-based assay technology have recognized problems in reproducibility, reliability and analytical sensitivity. These issues are often attributed to poor understanding and control of nucleic acid behaviors and properties at solid-liquid interfaces. Nucleic acid hybridization, central to DNA and RNA microarray formats, depends on the properties and behaviors of single strand (ss) nucleic acids (e.g., probe oligomeric DNA) bound to surfaces. ssDNA’s persistence length, radius of gyration, electrostatics, conformations on different surfaces and under various assay conditions, its chain flexibility and curvature, charging effects in ionic solutions, and fluorescent labeling all influence its physical chemistry and hybridization under assay conditions. Nucleic acid (e.g., both RNA and DNA) target interactions with immobilized ssDNA strands are highly impacted by these biophysical states. Furthermore, the kinetics, thermodynamics, and enthalpic and entropic contributions to DNA hybridization reflect global probe/target structures and interaction dynamics. Here we review several biophysical issues relevant to oligomeric nucleic acid molecular behaviors at surfaces and their influences on duplex formation that influence microarray assay performance. Correlation of biophysical aspects of single and double-stranded nucleic acids with their complexes in bulk solution is common. Such analysis at surfaces is not commonly reported, despite its importance to microarray assays. We seek to provide further insight into nucleic acid-surface challenges facing microarray diagnostic formats that have hindered their clinical adoption and compromise their research quality and value as genomics tools. PMID:24765522

  9. Improved Aerosol Optical Thickness, Columnar Water Vapor, and Surface Reflectance Retrieval from Combined CASI and SASI Airborne Hyperspectral Sensors

    Directory of Open Access Journals (Sweden)

    Hang Yang


    Full Text Available An increasingly common requirement in remote sensing is the integration of hyperspectral data collected simultaneously from different sensors (and fore-optics operating across different wavelength ranges. Data from one module are often relied on to correct information in the other, such as aerosol optical thickness (AOT and columnar water vapor (CWV. This paper describes problems associated with this process and recommends an improved strategy for processing remote sensing data, collected from both visible to near-infrared and shortwave infrared modules, to retrieve accurate AOT, CWV, and surface reflectance values. This strategy includes a workflow for radiometric and spatial cross-calibration and a method to retrieve atmospheric parameters and surface reflectance based on a radiative transfer function. This method was tested using data collected with the Compact Airborne Spectrographic Imager (CASI and SWIR Airborne Spectrographic Imager (SASI from a site in Huailai County, Hebei Province, China. Various methods for retrieving AOT and CWV specific to this region were assessed. The results showed that retrieving AOT from the remote sensing data required establishing empirical relationships between 465.6 nm/659 nm and 2105 nm, augmented by ground-based reflectance validation data, and minimizing the merit function based on AOT@550 nm optimization. The paper also extends the second-order difference algorithm (SODA method using Powell’s methods to optimize CWV retrieval. The resulting CWV image has fewer residual surface features compared with the standard methods. The derived remote sensing surface reflectance correlated significantly with the ground spectra of comparable vegetation, cement road and soil targets. Therefore, the method proposed in this paper is reliable enough for integrated atmospheric correction and surface reflectance retrieval from hyperspectral remote sensing data. This study provides a good reference for surface

  10. The multispectral reflectance of shortwave radiation by agricultural crops in relation with their morphological and optical properties

    NARCIS (Netherlands)

    Bunnik, N.J.J.


    Relations between morphological properties of uniform canopies. optical properties of the leaves and reflection of shortwave radiation, in the visible light region and the near infrared, by crops are the subject of this thesis.

    The aim of the study was a further investigation of

  11. Ice sintering timescales at the surface of Europa and implications for surface properties (United States)

    Phillips, C. B.; Molaro, J.; Meirion-Griffith, G.


    The planned exploration of Europa by NASA's Europa Clipper Mission and the possibility of a future Europa lander have driven the need to characterize its surface strength, roughness, porosity, thermal conductivity, and regolith depth in order to accurately interpret remote sensing data and develop appropriate spacecraft landing systems. Many processes contribute to Europa's landscape evolution, such as sputtering, mass wasting, thermal segregation, and impact gardening, driving the creation and distribution of icy regolith across the surface. While the efficacy of these processes are not well constrained, any amount of regolith emplaced at the surface will undergo subsequent processing due to sintering. Ice sintering is a form of frost metamorphism whereby contacting ice grains experience the diffusion of material into their contact region, forming a "neck" between them and densifying over time. Over long enough timescales, ice aggregates will sinter into solid material, which may contribute to the incorporation of non-ice material into Europa's subsurface and help to drive subsurface chemistry. Sintering also interacts with other processes, adding to the complexity of icy surface evolution. For example, sputtering preferentially removes larger grains and may enhance sintering rates, and changes in ice porosity may affect the response of the surface to micrometeorite impacts. Quantifying the effects of ice sintering will allow us to predict the microstructural properties of Europa's surface at spacecraft scales. To this end, we have modeled pressure-less (no overburden) sintering of spherical water-ice grains and validated the results with a laboratory experiment. We also modeled ice at the surface of Europa to obtain a first-order approximation of the sintering timescale and surface properties. Preliminary results indicate that ice grains will experience neck growth but not significant densification over Europa's surface age, suggesting that loose surface ice

  12. Plasma immersion ion implantation of polyurethane shape memory polymer: Surface properties and protein immobilization (United States)

    Cheng, Xinying; Kondyurin, Alexey; Bao, Shisan; Bilek, Marcela M. M.; Ye, Lin


    Polyurethane-type shape memory polymers (SMPU) are promising biomedical implant materials due to their ability to recover to a predetermined shape from a temporary shape induced by thermal activation close to human body temperature and their advantageous mechanical properties including large recovery strains and low recovery stresses. Plasma Immersion Ion Implantation (PIII) is a surface modification process using energetic ions that generates radicals in polymer surfaces leading to carbonisation and oxidation and the ability to covalently immobilise proteins without the need for wet chemistry. Here we show that PIII treatment of SMPU significantly enhances its bioactivity making SMPU suitable for applications in permanent implantable biomedical devices. Scanning Electron Microscopy (SEM), contact angle measurements, surface energy measurements, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterise the PIII modified surface, including its after treatment aging kinetics and its capability to covalently immobilise protein directly from solution. The results show a substantial improvement in wettability and dramatic changes of surface chemical composition dependent on treatment duration, due to the generation of radicals and subsequent oxidation. The SMPU surface, PIII treated for 200s, achieved a saturated level of covalently immobilized protein indicating that a full monolayer coverage was achieved. We conclude that PIII is a promising and efficient surface modification method to enhance the biocompatibility of SMPU for use in medical applications that demand bioactivity for tissue integration and stability in vivo.

  13. Imaging the spectral reflectance properties of bipolar radiofrequency-fused bowel tissue (United States)

    Clancy, Neil T.; Arya, Shobhit; Stoyanov, Danail; Du, Xiaofei; Hanna, George B.; Elson, Daniel S.


    Delivery of radiofrequency (RF) electrical energy is used during surgery to heat and seal tissue, such as vessels, allowing resection without blood loss. Recent work has suggested that this approach may be extended to allow surgical attachment of larger tissue segments for applications such as bowel anastomosis. In a large series of porcine surgical procedures bipolar RF energy was used to resect and re-seal the small bowel in vivo with a commercial tissue fusion device (Ligasure; Covidien PLC, USA). The tissue was then imaged with a multispectral imaging laparoscope to obtain a spectral datacube comprising both fused and healthy tissue. Maps of blood volume, oxygen saturation and scattering power were derived from the measured reflectance spectra using an optimised light-tissue interaction model. A 60% increase in reflectance of visible light (460-700 nm) was observed after fusion, with the tissue taking on a white appearance. Despite this the distinctive shape of the haemoglobin absorption spectrum was still noticeable in the 460-600 nm wavelength range. Scattering power increased in the fused region in comparison to normal serosa, while blood volume and oxygen saturation decreased. Observed fusion-induced changes in the reflectance spectrum are consistent with the biophysical changes induced through tissue denaturation and increased collagen cross-linking. The multispectral imager allows mapping of the spatial extent of these changes and classification of the zone of damaged tissue. Further analysis of the spectral data in parallel with histopathological examination of excised specimens will allow correlation of the optical property changes with microscopic alterations in tissue structure.

  14. Electronic and Optical Properties of Aluminum Oxide Before and After Surface Reduction by Ar+ Bombardment

    Directory of Open Access Journals (Sweden)

    D. Tahir


    Full Text Available The electronic and optical properties of a-Al2O3 after induced by 3-keV Ar+ sputtering have been studied quantitatively by use of reflection electron energy loss spectroscopy (REELS spectra. The band gap values of a-Al2O3 was determined from the onset values of the energy loss spectrum to the background level of REELS spectra as a function of time Ar+ bombardment. The bandgap changes from 8.4 eV before sputtering to 6.2 eV after 4 minutes of sputtering.The optical properties of α-Al2O3 thin films have been determined by comparing the experimental cross section obtained from reflection electron energy loss spectroscopy with the theoretical inelastic scattering cross section, deduced from the simulated energy loss function (ELF by using QUEELS-ε(k-REELS software. The peak assignments are based on ELF and compared with reported data on the electronic structure of α-Al2O3 obtained using different techniques. The results demonstrate that the electronic and optical properties before and after surface reduction will provide further understanding in the fundamental properties of α-Al2O3 which will be useful in the design, modeling and analysis of devices applications performance.

  15. Stable isotopes of Hawaiian spiders reflect substrate properties along a chronosequence

    Directory of Open Access Journals (Sweden)

    Susan R. Kennedy


    Full Text Available The Hawaiian Islands offer a unique opportunity to test how changes in the properties of an isolated ecosystem are propagated through the organisms that occur within that ecosystem. The age-structured arrangement of volcanic-derived substrates follows a regular progression over space and, by inference, time. We test how well documented successional changes in soil chemistry and associated vegetation are reflected in organisms at higher trophic levels—specifically, predatory arthropods (spiders—across a range of functional groups. We focus on three separate spider lineages: one that builds capture webs, one that hunts actively, and one that specializes on eating other spiders. We analyze spiders from three sites across the Hawaiian chronosequence with substrate ages ranging from 200 to 20,000 years. To measure the extent to which chemical signatures of terrestrial substrates are propagated through higher trophic levels, we use standard stable isotope analyses of nitrogen and carbon, with plant leaves included as a baseline. The target taxa show the expected shift in isotope ratios of δ15N with trophic level, from plants to cursorial spiders to web-builders to spider eaters. Remarkably, organisms at all trophic levels also precisely reflect the successional changes in the soil stoichiometry of the island chronosequence, demonstrating how the biogeochemistry of the entire food web is determined by ecosystem succession of the substrates on which the organisms have evolved.

  16. Surface Properties of Photo-Oxidized Bituminous Coals: Final report

    Energy Technology Data Exchange (ETDEWEB)



    Natural weathering has a detrimental effect on the hydrophobic nature of coal, which in turn can influence clean-coal recovery during flotation. Few techniques are available that can establish the quality of coal surfaces and that have a short analysis time to provide input for process control. Luminescence emissions which can be quantified with an optical microscope and photometer system, are measurably influenced by degree of weathering as well as by mild storage deterioration. In addition, it has been shown that when vitrinite is irradiated with a relatively high intensity flux of violet- or ultraviolet- light in the presence of air, photo-oxidation of the surface occurs. The combination of measuring the change in luminescence emission intensity with degree of surface oxidation provided the impetus for the current investigation. The principal aim of this research was to determine whether clear correlations could be established among surface oxygen functionality, hydrophobicity induced by photo-oxidation, and measurements of luminescence intensity and alteration. If successful, the project would result in quantitative luminescence techniques based on optical microscopy that would provide a measure of the changes in surface properties as a function of oxidation and relate them to coal cleanability. Two analytical techniques were designed to achieve these goals. Polished surfaces of vitrain bands or a narrow size fraction of powdered vitrain concentrates were photo-oxidized using violet or ultraviolet light fluxes and then changes in surface properties and chemistry were measured using a variety of near-surface analytical techniques. Results from this investigation demonstrate that quantitative luminescence intensity measurements can be performed on fracture surfaces of bituminous rank coals (vitrains) and that the data obtained do reveal significant variations depending upon the level of surface oxidation. Photo-oxidation induced by violet or ultraviolet light

  17. An internally reflecting Cherenkov detector (DIRC): Properties of the fused silica radiators

    International Nuclear Information System (INIS)

    Adam, I.; Aston, D.


    The DIRC, a new type of ring-imaging Cherenkov detector that images internally reflected Cherenkov light, is being constructed as the main hadronic particle identification component of the BABAR detector at SLAC. The device makes use of 5 meter long fused silica (colloquially called quartz) bars, which serve both as the Cherenkov radiators and as light pipes for transmitting the light to an array of photo-multiplier tubes. This paper describes a program of research and development aimed at determining whether bars that meet the stringent requirements of the DIRC can be obtained from commercial sources. The results of studies of bulk absorption of fused silica, surface finish, radiation damage and bulk inhomogeneities are discussed

  18. Constraining the surface properties of effective Skyrme interactions (United States)

    Jodon, R.; Bender, M.; Bennaceur, K.; Meyer, J.


    Background: Deformation energy surfaces map how the total binding energy of a nuclear system depends on the geometrical properties of intrinsic configurations, thereby providing a powerful tool to interpret nuclear spectroscopy and large-amplitude collective-motion phenomena such as fission. The global behavior of the deformation energy is known to be directly connected to the surface properties of the effective interaction used for its calculation. Purpose: The precise control of surface properties during the parameter adjustment of an effective interaction is key to obtain a reliable and predictive description of nuclear properties. The most relevant indicator is the surface-energy coefficient asurf. There are several possibilities for its definition and estimation, which are not fully equivalent and require a computational effort that can differ by orders of magnitude. The purpose of this study is threefold: first, to identify a scheme for the determination of asurf that offers the best compromise between robustness, precision, and numerical efficiency; second, to analyze the correlation between values for asurf and the characteristic energies of the fission barrier of 240Pu; and third, to lay out an efficient and robust procedure for how the deformation properties of the Skyrme energy density functional (EDF) can be constrained during the parameter fit. Methods: There are several frequently used possibilities to define and calculate the surface energy coefficient asurf of effective interactions built for the purpose of self-consistent mean-field calculations. The most direct access is provided by the model system of semi-infinite nuclear matter, but asurf can also be extracted from the systematics of binding energies of finite nuclei. Calculations can be carried out either self-consistently [Hartree-Fock (HF)], which incorporates quantal shell effects, or in one of the semiclassical extended Thomas-Fermi (ETF) or modified Thomas-Fermi (MTF) approximations. The

  19. Surface Charge and Ion Sorption Properties of Titanium Dioxide (United States)

    Ridley, M. K.; Machesky, M. L.; Wesolowski, D. J.; Finnegan, M. P.; Palmer, D. A.


    The interaction of submicron metal oxide particles with natural aqueous solutions results in the hydroxylation of surface sites, which impart a pH-dependent surface charge. The charged submicron particles influence processes such as nanoparticle assembly and alteration, crystal growth rates and morphologies, colloid flocculation, and contaminant transport. The surface charge and ion sorption properties of metal-oxide particles may be studied by potentiometric titrations, using hydrogen-electrode concentration-cells or traditional glass electrodes and an autotitrator. These techniques have been used to quantify the adsorption of various ions (Na+, Rb+, Ca2+, Sr2+, Cl-) on rutile, at ionic strengths up to 1.0 molality and temperatures to 250° C. The crystalline rutile used in these studies is less than 400 nm in diameter, has a BET surface area of 17 m2/g, and the 110 and 100 faces predominate. The negative surface charge of the rutile was enhanced by increasing temperature, increasing ionic strength, and decreasing the ionic radii of the electrolyte cation. Moreover, the addition of a divalent cation significantly enhances the negative charge of the rutile surface. These data have been rationalized with the MUSIC model of Hiemestra and van Riemsdijk, and a Basic Stern layer description of the electric double layer (EDL). Model fitting of the experimental data provides binding constants for the adsorbed counterions and divalent cations, and capacitance values as well as corresponding electrical potential values of the binding planes. Recently, new studies have been initiated to determine particle size affects on the proton induced surface charge and ion sorption properties of titanium dioxide. In these studies, anatase with a BET surface area of 40 and 100 m2/g (primary particle sizes of 40 and 10 nm, respectively) is being investigated. The complexity of both the experimental and modeling procedures increases with decreasing particle size. For example, the fine

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

    Directory of Open Access Journals (Sweden)

    David J. Diner


    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.

  1. Non-invasive identification of metal-oxalate complexes on polychrome artwork surfaces by reflection mid-infrared spectroscopy. (United States)

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


    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.

  2. Influence of short chain organic acids and bases on the wetting properties and surface energy of submicrometer ceramic powders. (United States)

    Neirinck, Bram; Soccol, Dimitri; Fransaer, Jan; Van der Biest, Omer; Vleugels, Jef


    The effect of short chained organic acids and bases on the surface energy and wetting properties of submicrometer alumina powder was assessed. The surface chemistry of treated powders was determined by means of Diffuse Reflectance Infrared Fourier Transform spectroscopy and compared to untreated powder. The wetting of powders was measured using a modified Washburn method, based on the use of precompacted powder samples. The geometric factor needed to calculate the contact angle was derived from measurements of the porous properties of the powder compacts. Contact angle measurements with several probe liquids before and after modification allowed a theoretical estimation of the surface energy based on the surface tension component theory. Trends in the surface energy components were linked to observations in infrared spectra. The results showed that the hydrophobic character of the precompacted powder depends on both the chain length and polar group of the modifying agent. Copyright 2010 Elsevier Inc. All rights reserved.

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

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


    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 (light, MRSA concentrations on average were reduced by 5.2 log 10 (1.4 log 10 GSD) with standard paint and 5.1 log 10 (1.2 log 10 GSD) with UV-reflective paint (p = 0.017) and VRE by 4.4 log 10 (1.4 log 10 GSD) with standard paint and 5.3 log 10 (1.1 log 10 GSD) with UV-reflective paint (p bacteria on various surfaces compared to standard paint, particularly at a surface placement site indirectly exposed to UVC light.

  4. Influence of surface roughness on the friction property of textured surface

    Directory of Open Access Journals (Sweden)

    Yuankai Zhou


    Full Text Available In contrast with dimple textures, surface roughness is a texture at the micro-scale, essentially which will influence the load-bearing capacity of lubricant film. The numerical simulation was carried out to investigate the influence of surface roughness on friction property of textured surface. The lubricant film pressure was obtained using the method of computational fluid dynamics according to geometric model of round dimple, and the renormalization-group k–ε turbulent model was adopted in the computation. The numerical simulation results suggest that there is an optimum dimensionless surface roughness, and near this value, the maximum load-bearing capacity can be achieved. The load-bearing capacity is determined by the surface texture, the surface roughness, and the interaction between them. To get information of friction coefficient, the experiments were conducted. This experiment was used to evaluate the simulation. The experimental results show that for the frequency of 4 and 6 Hz, friction coefficient decreases at first and then increases with decreasing surface roughness, which indicates that there exists the optimum region of surface roughness leading to the best friction reduction effect, and it becomes larger when area fractions increase from 2% to 10%. The experimental results agree well with the simulation results.

  5. Magnetic nanoparticles: surface effects and properties related to biomedicine applications. (United States)

    Issa, Bashar; Obaidat, Ihab M; Albiss, Borhan A; Haik, Yousef


    Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways (e.g., chemical and physical) with controllable sizes enabling their comparison to biological organisms from cells (10-100 μm), viruses, genes, down to proteins (3-50 nm). The optimization of the nanoparticles' size, size distribution, agglomeration, coating, and shapes along with their unique magnetic properties prompted the application of nanoparticles of this type in diverse fields. Biomedicine is one of these fields where intensive research is currently being conducted. In this review, we will discuss the magnetic properties of nanoparticles which are directly related to their applications in biomedicine. We will focus mainly on surface effects and ferrite nanoparticles, and on one diagnostic application of magnetic nanoparticles as magnetic resonance imaging contrast agents.

  6. In vivo characterization of structural and optical properties of human skin by combined photothermal radiometry and diffuse reflectance spectroscopy (United States)

    Verdel, Nina; Marin, Ana; Vidovič, Luka; Milanič, Matija; Majaron, Boris


    We have combined two optical techniques to enable simultaneous assessment of structure and composition of human skin in vivo: Pulsed photothermal radiometry (PPTR), which involves measurements of transient dynamics in midinfrared emission from sample surface after exposure to a light pulse, and diffuse reflectance spectroscopy (DRS) in visible part of the spectrum. Namely, while PPTR is highly sensitive to depth distribution of selected absorbers, DRS provides spectral information and thus enables differentiation between various chromophores. The accuracy and robustness of the inverse analysis is thus considerably improved compared to use of either technique on its own. Our analysis approach is simultaneous multi-dimensional fitting of the measured PPTR signals and DRS with predictions from a numerical model of light-tissue interaction (a.k.a. inverse Monte Carlo). By using a three-layer skin model (epidermis, dermis, and subcutis), we obtain a good match between the experimental and modeling data. However, dividing the dermis into two separate layers (i.e., papillary and reticular dermis) helps to bring all assessed parameter values within anatomically and physiologically plausible intervals. Both the quality of the fit and the assessed parameter values depend somewhat on the assumed scattering properties for skin, which vary in literature and likely depend on subject's age and gender, anatomical site, etc. In our preliminary experience, simultaneous fitting of the scattering properties is possible and leads to considerable improvement of the fit. The described approach may thus have a potential for simultaneous determination of absorption and scattering properties of human skin in vivo.

  7. Mechanical properties and surface characteristics of three archwire alloys. (United States)

    Krishnan, Vinod; Kumar, K Jyothindra


    Recent developments in material science have presented newer archwire materials as well as improvements in the properties of existing ones. Proper selection and understanding of the biomechanical requirement of each case requires proper characterization studies on archwire alloys. The present study characterizes and compares three orthodontic archwire alloys, stainless steel, beta titanium alloy (TMA), and a newly introduced titanium alloy (TiMolium), for the parameters (1) ultimate tensile strength (UTS), 0.02% offset yield strength (YS), and modulus of elasticity (E); (2) load deflection characteristics; (3) frictional properties; (4) surface characteristics and (5) elemental analysis for TiMolium. Seven specimens of each archwire alloy were used for evaluating each parameter. An instron universal testing machine was used for tensile testing, three-point bend testing, and evaluation of frictional characteristics. Scanning electron microscope was used for surface evaluation and X-ray fluorescence for elemental analysis of TiMolium wire specimens. Stainless steel was the strongest archwire alloy with high UTS, E, 0.02% offset YS, and less friction at the archwire-bracket interface. TMA wires exhibited better load deflection characteristics with less stiffness than the other two wires. The surface of TMA appeared rough and exhibited very high values for friction at the archwire-bracket interface. TiMolium appeared to be an alpha-beta titanium alloy composed of titanium, aluminum, and vanadium and intermediate in nature for all the parameters evaluated.

  8. Land Surface Reflectance Retrieval from Hyperspectral Data Collected by an Unmanned Aerial Vehicle over the Baotou Test Site (United States)

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


    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

  9. Land surface reflectance retrieval from hyperspectral data collected by an unmanned aerial vehicle over the Baotou test site. (United States)

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


    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).

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

    Energy Technology Data Exchange (ETDEWEB)

    Takaura, Norikatsu


    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

  11. Light depolarization in off-specular reflection on submicro rough metal surfaces with imperfectly random roughness. (United States)

    Liu, Linsheng; Li, Xuefeng; Nonaka, Kazuhiro


    Depolarization at a rough surface relates to its roughness and irregularity (e.g., sags and crests) besides the material property. However, there is still lack of general theory to clearly describe the relationship between depolarization ratios and surface conditions, and one important reason is that the mechanism of depolarization relates to geometric parameters such as microcosmic height/particle distributions of sub-micro to nm levels. To study the mechanism in more detail, a compact laser instrument is developed, and depolarization information of a linearly polarized incident light is used for analyzing the roughness, during which a He-Ne laser source (λ = 632.8 nm) is used. Three nickel specimens with RMS roughness (Rq) less than λ/4 are fabricated and tested. Six different areas in each specimen are characterized in detail using an AFM. Rq are in the range of 34.1-155.0 nm, and the heights are non-Gaussian distribution in the first specimen and near-Gaussian distribution in the others. Off-specular inspection is carried out exactly on these 18 characterized areas, and results show that the cross-polarization ratios match quite well with Rq values of the first sample that has Rq ≤ λ/10 (or Rt ≤ λ), while they match well with maximum height, Rt, values of the other two that have Rt > λ (the maximum derivation is 11%). In addition, since this instrument is simple, portable, stable, and low-cost, it has great potential for practical online roughness testing after a linear calibration.

  12. Measurements of reflectance spectra of ion-bombarded ice and application to surfaces in the outer Solar System

    International Nuclear Information System (INIS)

    O'Shaughnessy, D.J.; Boring, J.W.; Johnson, R.E.


    A number of the icy satellites of the outer planets exhibit interesting hemispherical differences in brightness which have been attributed to enhanced bombardment by the local plasma of one hemisphere. The plasma bombardment is thought to erode the icy surfaces and implant species, thereby altering the surface reflectance spectra, as well as producing fresh plasma. Here we present the first results of laboratory measurements of the wavelength dependence of the alteration of the visible reflectance spectra of H 2 O ice irradiated by keV ions. When the implanted species is chemically neutral, absorption is slightly enhanced below 0.55 μm. For an incident species containing sulphur, a strong absorption feature is produced at 0.4 μm corresponding (probably) to S 3 . This occurs at too large a wavelength to account for the absorption feature observed at Europa by Voyager and therefore casts doubt on the recent interpretations of the reflectance data of Europa. (author)

  13. MODIS/Aqua L2 Surface Reflectance, 5-Min Swath 250m, 500m, and 1km (United States)

    National Aeronautics and Space Administration — MODIS/Aqua L2 Surface Reflectance, 5-Min Swath 250m, 500m, and 1km (MYD09). This product is computed from the MODIS Level 1B land bands 1, 2, 3, 4, 5, 6, and 7...

  14. MODIS/Aqua Near Real Time (NRT) Surface Reflectance Daily L2G Global 500m SIN Grid (United States)

    National Aeronautics and Space Administration — The MODIS Near Real Time (NRT) Surface Reflectance Daily L2G Global 500m SIN Grid product, MYD09GHK, is a seven-band product computed from the MODIS Level 1B land...

  15. Fluorine-containing composition for forming anti-reflection film on resist surface and pattern formation method (United States)

    Nishi, Mineo; Makishima, Hideo


    A composition for forming anti-reflection film on resist surface which comprises an aqueous solution of a water soluble fluorine compound, and a pattern formation method which comprises the steps of coating a photoresist composition on a substrate; coating the above-mentioned composition for forming anti-reflection film; exposing the coated film to form a specific pattern; and developing the photoresist, are provided. Since the composition for forming anti-reflection film can be coated on the photoresist in the form of an aqueous solution, not only the anti-reflection film can be formed easily, but also, the film can be removed easily by rinsing with water or alkali development. Therefore, by the pattern formation method according to the present invention, it is possible to form a pattern easily with a high dimensional accuracy.

  16. Combined surface acoustic wave and surface plasmon resonance measurement of collagen and fibrinogen layer physical properties

    Directory of Open Access Journals (Sweden)

    J.-M. Friedt


    Full Text Available We use an instrument combining optical (surface plasmon resonance and acoustic (Love mode surface acoustic wave device real-time measurements on a same surface for the identification of water content in collagen and fibrinogen protein layers. After calibration of the surface acoustic wave device sensitivity by copper electrodeposition and surfactant adsorption, the bound mass and its physical properties – density and optical index – are extracted from the complementary measurement techniques and lead to thickness and water ratio values compatible with the observed signal shifts. Such results are especially usefully for protein layers with a high water content as shown here for collagen on an hydrophobic surface. We obtain the following results: collagen layers include 70±20% water and are 16±3 to 19±3 nm thick for bulk concentrations ranging from 30 to 300 μg/ml. Fibrinogen layers include 50±10% water for layer thicknesses in the 6±1.5 to 13±2 nm range when the bulk concentration is in the 46 to 460 μg/ml range. Keywords: surface acoustic wave, surface plasmon resonance, collagen, fibrinogen, density, thickness

  17. Nonlinear mean field theory for nuclear matter and surface properties

    International Nuclear Information System (INIS)

    Boguta, J.; Moszkowski, S.A.


    Nuclear matter properties are studied in a nonlinear relativistic mean field theory. We determine the parameters of the model from bulk properties of symmetric nuclear matter and a reasonable value of the effective mass. In this work, we stress the nonrelativistic limit of the theory which is essentially equivalent to a Skyrme hamiltonian, and we show that most of the results can be obtained, to a good approximation, analytically. The strength of the required parameters is determined from the binding energy and density of nuclear matter and the effective nucleon mass. For realistic values of the parameters, the nonrelativistic approximation turns out to be quite satisfactory. Using reasonable values of the parameters, we can account for other key properties of nuclei, such as the spin-orbit coupling, surface energy, and diffuseness of the nuclear surface. Also the energy dependence of the nucleon-nucleus optical model is accounted for reasonably well except near the Fermi surface. It is found, in agreement with empirical results, that the Landau parameter F 0 is quite small in normal nuclear matter. Both density dependence and momentum dependence of the NN interaction, but especially the former, are important for nuclear saturation. The required scalar and vector coupling constants agree fairly well with those obtained from analyses of NN scattering phase shifts with one-boson-exchange models. The mean field theory provides a semiquantitative justification for the weak Skyrme interaction in odd states. The strength of the required nonlinear term is roughly consistent with that derived using a new version of the chiral mean field theory in which the vector mass as well as the nucleon mass is generated by the sigma-field. (orig.)

  18. Microstructure and surface mechanical properties of pulse electrodeposited nickel

    Energy Technology Data Exchange (ETDEWEB)

    Ul-Hamid, A., E-mail: [Center of Research Excellence in Corrosion (CoRE-C), Research Institute, King Fahd University of Petroleum and Minerals, P.O. Box 1073, Dhahran 31261 (Saudi Arabia); Dafalla, H.; Quddus, A.; Saricimen, H.; Al-Hadhrami, L.M. [Center of Research Excellence in Corrosion (CoRE-C), Research Institute, King Fahd University of Petroleum and Minerals, P.O. Box 1073, Dhahran 31261 (Saudi Arabia)


    The surface of carbon steel was modified by electrochemical deposition of Ni in a standard Watt's bath using dc and pulse plating electrodeposition. The aim was to compare the microstructure and surface mechanical properties of the deposit obtained by both techniques. Materials characterization was conducted using field emission scanning electron microscope fitted with scanning transmission electron detector, atomic force microscope and X-ray diffractometer. Nanoindentation hardness, elastic modulus, adhesion, coefficients of friction and wear rates were determined for both dc and pulse electrodeposits. Experimental results indicate that pulse electrodeposition produced finer Ni grains compared to dc plating. Size of Ni grains increased with deposition. Both dc and pulse deposition resulted in grain growth in preferred (2 0 0) orientation. However, presence of Ni (1 1 1) grains increased in deposits produced by pulse deposition. Pulse plated Ni exhibited higher hardness, creep and coefficient of friction and lower modulus of elasticity compared to dc plated Ni.

  19. Surface Properties of Metal Hydroxide Microparticles in the Ambient Air

    Directory of Open Access Journals (Sweden)

    Zakharenko Valery


    Full Text Available The adsorption and photoadsorption properties of Mg(OH2 and Ca(OH2 microparticles in the ambient air were investigated. The compositional analysis of an adsorption layer of microparticles was carried out. The kinetics of photodesorption of molecules from microcrystal surfaces and the interaction of HCFC-22 (CHF2Cl in the dark and under light were studied. Quantum yields and their spectral dependencies were determined for CO2 photodesorption, O2 and CO photoadsorption. The effect of weakly bound CO displacement from the surface of microparticles was revealed during dark adsorption of HCFC-22. It is supposed that adsorbed CO is formed as a result of atmospheric CO2 reduction after the break of Mg—OH bonds. In case of calcium hydroxide, CO is generated during the interaction of calcium hydroxide with carbon dioxide in the presence of water.

  20. Molecular dynamics simulations on surface properties of silicon dioxide melts

    CERN Document Server

    Röder, A


    In the present thesis the surface properties of a silicon dioxide melt were studied. As first systems drops (i.e. sytems without periodic boundary conditions) of N=432, 1536, as well as 4608 atoms were considered. The second analyzed geometry corresponds to that of a thin film, i. e. periodic boundary conditions in x- and y-direction were present, while in z-direction one had a free surface. In this case a system of N=1152 atoms was considered. As model potential the two-body potential proposed by Beest, Kramer, and van Santen was applied. For both geometries five temperatures were considered, which lied in the range of 3000 K

  1. Surface properties of poly(imide-co-siloxane) block copolymers

    Czech Academy of Sciences Publication Activity Database

    Novák, I.; Sysel, P.; Chodák, I.; Špírková, Milena; Janigová, I.


    Roč. 103, č. 13 (2009), s76-s78 ISSN 0009-2770. [PMA 2009 &20th SRC . Bratislava, 21.04.2009/23.04.2009] R&D Projects: GA AV ČR IAA100100622; GA AV ČR IAA400500505 Grant - others:Slovak Scientific Agency(SK) VEGA2/7103/27 Institutional research plan: CEZ:AV0Z40500505 Keywords : Poly(imide-siloxane) * surface properties * morphology Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.717, year: 2009

  2. Surface property modification of coatings via self-stratification (United States)

    Pieper, Robert Joseph

    Biological fouling occurs everywhere in the marine environment and is a significant problem for marine vessels. Anti-fouling coatings have been used effectively to prevent fouling; however, these coatings harm non-targeted sea-life. Fouling-release coatings (FRC) appear to be an alternative way to combat fouling. FRC do not necessarily prevent the settlement of marine organisms but rather allow their easy removal with application of shear to the coatings surface. These coatings must be non-toxic, non-leaching, have low surface energy, low modulus, and durability to provide easy removal of marine organisms. Here the goal is to develop FRC based on thermosetting siloxane-polyurethane, amphiphilic polyurethane, and zwitterionic/amphiphilic polyurethane systems. A combinatorial high-throughput approach has been taken in order to explore the variables that may affect the performance of the final coatings. Libraries of acrylic polyols were synthesized using combinatorial high-throughput techniques by either batch or semi-batch processes. The design of the experiments for the batch and semi-batch processes were done combinatorially to explore a range of compositions and various reaction process variables that cannot be accomplished or are not suitable for single reaction experiments. Characterization of Rapid-GPC, high-throughput DSC, and gravimetrically calculated percent solids verified the effects of different reaction conditions on the MW, glass transition temperatures, and percent conversion of the different compositions of acrylic polyols. Coatings were characterized for their surface energy, pseudobarnacle pull-off adhesion, and were subjected to bioassays including marine bacteria, algae, and barnacles. From the performance properties results the acrylic polyol containing 20% hydroxyethyl acrylate and 80% butyl acrylate was selected for further siloxane-polyurethane formulations and were subjected to the same physical, mechanical, and performance testing

  3. Molluscicidal properties and selective toxicity of surface-active agents (United States)

    Visser, S. A.


    Of over 100 commercially produced surface-active agents tested against the bilharziasis vector snail Biomphalaria sudanica, 13 were found to possess considerable and highly selective molluscicidal properties at concentrations of less than 1 ppm for exposures of 48 hours. Against crustacea, fish, water plants, mosquito larvae, mice, and the eggs of B. sudanica, the toxicities of the 13 surfactants were slight. The chemicals did not appear to be absorbed by organic matter to any appreciable extent. It is thought that the toxicity to B. sudanica is of both a chemical and a physical nature. PMID:5294185

  4. Effect of nanofillers' size on surface properties after toothbrush abrasion. (United States)

    Cavalcante, Larissa M; Masouras, Konstantinos; Watts, David C; Pimenta, Luiz A; Silikas, Nick


    To investigate the effect of filler-particle size of experimental and commercial resin composites, undergoing toothbrush abrasion, on three surface properties: surface roughness (SR), surface gloss (G) and color stability (CS). Four model (Ivoclar/Vivadent) and one commercial resin composite (Tokuyama) with varying filler-size from 100-1000 nm were examined. Six discs (10 mm x 2 mm) from each product were prepared and mechanically polished. The samples were then submitted to 20,000 brushing strokes in a toothbrush abrasion machine. SR parameters (Ra, Rt and RSm), G, and CS were measured before and after toothbrush abrasion. Changes in SR and G were analyzed by 2-way ANOVA, with Bonferroni post hoc test. CS values were submitted to one-way ANOVA and Bonferroni post hoc test (alpha=0.05). Initial G values ranged between 73-87 gloss units (GU) and were reduced after toothbrush abrasion to a range of 8-64 GU. Toothbrush abrasion resulted in significant modifications in SR and G amongst the materials tested, attributed to filler sizes. There was statistically significant difference in color (delta E* ranged from 0.38-0.88). Filler size did not affect color stability. Toothbrush abrasion resulted in rougher and matte surfaces for all materials tested. Although the individual differences in surface roughness among filler sizes were not always significant, the correlation showed a trend that larger filler sizes resulted in higher surface roughness after abrasion for the SR parameters Ra and Rt (r = 0.95; r = 0.93, respectively). RSm showed an increase after toothbrush abrasion for all resin composites, however no significant correlation was detected (r = 0.21).There was a significant correlation between G and Ra ratios (r = - 0.95).

  5. A Framework for Estimating the 30 m Thermal-Infrared Broadband Emissivity From Landsat Surface Reflectance Data (United States)

    Cheng, Jie; Liu, Hao; Liang, Shunlin; Nie, Aixiu; Liu, Qiang; Guo, Yamin


    The land surface thermal-infrared broadband emissivity (BBE) is a vital variable for estimating land surface radiation budgets (SRBs). We develop a framework for retrieving the 30 m BBE from Landsat surface reflectance data to estimate SRBs at finer scales and validate coarse resolution data. In the developed framework, the land surface is classified as bare soils and vegetated surfaces to allow different algorithms to be used for the BBE estimation. We propose a downscaling algorithm that uses the empirical relationship between the Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) BBE and Landsat surface reflectance at 90 m to retrieve the 30 m BBE over bare soils. A look-up table (LUT)-based algorithm is proposed for vegetated surfaces. The BBE is interpolated from a LUT that is constructed from the 4SAIL radiative transfer model with inputs of the leaf BBE, the soil background BBE, and the leaf area index (LAI). Ground measurements that were collected at 11 relatively homogeneous sandy sites during three independent field campaigns are used to validate the proposed algorithm over bare soils. The average difference between the retrieved and field-measured BBEs is 0.012. We produce the land surface BBE of China in 2008 by using the developed framework and composited winter and summer seasonal BBE maps. The composited seasonal BBE maps are compared to the seasonal BBE maps derived from the ASTER emissivity product. The bias is within ±0.005 over bare soils and ranges from 0.012 to 0.019 over vegetated surfaces. Combined with the validated results in this study and published references, the comparison results demonstrate the good performance of the developed framework. This study provides a new perspective on estimating BBEs from sensors with only a thermal-infrared channel.

  6. Surface orientation effects on bending properties of surgical mesh are independent of tensile properties. (United States)

    Simon, David D; Andrews, Sharon M; Robinson-Zeigler, Rebecca; Valdes, Thelma; Woods, Terry O


    Current mechanical testing of surgical mesh focuses primarily on tensile properties even though implanted devices are not subjected to pure tensile loads. Our objective was to determine the flexural (bending) properties of surgical mesh and determine if they correlate with mesh tensile properties. The flexural rigidity values of 11 different surgical mesh designs were determined along three textile directions (machine, cross-machine, and 45° to machine; n = 5 for each) using ASTM D1388-14 while tracking surface orientation. Tensile testing was also performed on the same specimens using ASTM D882-12. Linear regressions were performed to compare mesh flexural rigidity to mesh thickness, areal mass density, filament diameter, ultimate tensile strength, and maximum extension. Of 33 mesh specimen groups, 30 had significant differences in flexural rigidity values when comparing surface orientations (top and bottom). Flexural rigidity and mesh tensile properties also varied with textile direction (machine and cross-machine). There was no strong correlation between the flexural and tensile properties, with mesh thickness having the best overall correlation with flexural rigidity. Currently, surface orientation is not indicated on marketed surgical mesh, and a single mesh may behave differently depending on the direction of loading. The lack of correlation between flexural stiffness and tensile properties indicates the need to examine mesh bending stiffness to provide a more comprehensive understanding of surgical mesh mechanical behaviors. Further investigation is needed to determine if these flexural properties result in the surgical mesh behaving mechanically different depending on implantation direction. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 854-862, 2018. © 2017 Wiley Periodicals, Inc.

  7. Modification of polyvinyl alcohol surface properties by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Pukhova, I.V., E-mail: [National Research Tomsk State University, 36 Lenin Ave, Tomsk 634050 (Russian Federation); Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation); Kurzina, I.A. [National Research Tomsk State University, 36 Lenin Ave, Tomsk 634050 (Russian Federation); Savkin, K.P. [Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation); Laput, O.A. [National Research Tomsk Polytechnic University, 30 Lenin Ave, Tomsk 634050 (Russian Federation); Oks, E.M. [Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation)


    We describe our investigations of the surface physicochemical properties of polyvinyl alcohol modified by silver, argon and carbon ion implantation to doses of 1 × 10{sup 14}, 1 × 10{sup 15} and 1 × 10{sup 16} ion/cm{sup 2} and energies of 20 keV (for C and Ar) and 40 keV (for Ag). Infrared spectroscopy (IRS) indicates that destructive processes accompanied by chemical bond (−C=O) generation are induced by implantation, and X-ray photoelectron spectroscopy (XPS) analysis indicates that the implanted silver is in a metallic Ag3d state without stable chemical bond formation with polymer chains. Ion implantation is found to affect the surface energy: the polar component increases while the dispersion part decreases with increasing implantation dose. Surface roughness is greater after ion implantation and the hydrophobicity increases with increasing dose, for all ion species. We find that ion implantation of Ag, Ar and C leads to a reduction in the polymer microhardness by a factor of five, while the surface electrical resistivity declines modestly.

  8. Recent research on anidolic daylighting systems: highly reflective coating materials and chronobiological properties (United States)

    Linhart, Friedrich; Wittkopf, Stephen K.; Münch, Mirjam; Scartezzini, Jean-Louis


    Making daylight more available in buildings is highly desirable for reasons of energy efficiency, visual comfort, occupant well-being and health. The Anidolic Integrated Ceiling (AIC) is a highly efficient daylighting system, designed to gather and redirect daylight from the outside of a building into its interior with minimal losses. The reflective coating materials used within AICs have a major impact on the optical efficiency of such systems. The first part of our article presents a new computer model of an AIC consisting of more than 30 distinct components. We discuss on which of them the use of expensive, highly reflective coatings makes the most sense. We conclude that coating the component "Anidolic element 1" is always a good choice and that considerable financial savings can be obtained by following an appropriate optimization sequence.The second part of our article discusses chronobiological properties of Anidolic Daylighting Systems (ADS). We recorded daytime irradiance values for several weeks from March to May 2009 in an experimental office setup in our laboratory using a portable digital spectroradiometer. Our results showed to which extent different sky conditions influenced daylight exposure of office workers in an ADS-equipped office room. We conclude that for the tested ADS-equipped office room, daylight supply can be considered largely sufficient during long periods on most working days. However, complementary artificial lighting with blue-enriched polychromatic fluorescent tubes might be useful on days with predominantly overcast skies as well as before 09:00 and after 16:30 on all days.

  9. Engineered Surface Properties of Porous Tungsten from Cryogenic Machining (United States)

    Schoop, Julius Malte

    Porous tungsten is used to manufacture dispenser cathodes due to it refractory properties. Surface porosity is critical to functional performance of dispenser cathodes because it allows for an impregnated ceramic compound to migrate to the emitting surface, lowering its work function. Likewise, surface roughness is important because it is necessary to ensure uniform wetting of the molten impregnate during high temperature service. Current industry practice to achieve surface roughness and surface porosity requirements involves the use of a plastic infiltrant during machining. After machining, the infiltrant is baked and the cathode pellet is impregnated. In this context, cryogenic machining is investigated as a substitutionary process for the current plastic infiltration process. Along with significant reductions in cycle time and resource use, surface quality of cryogenically machined un-infiltrated (as-sintered) porous tungsten has been shown to significantly outperform dry machining. The present study is focused on examining the relationship between machining parameters and cooling condition on the as-machined surface integrity of porous tungsten. The effects of cryogenic pre-cooling, rake angle, cutting speed, depth of cut and feed are all taken into consideration with respect to machining-induced surface morphology. Cermet and Polycrystalline diamond (PCD) cutting tools are used to develop high performance cryogenic machining of porous tungsten. Dry and pre-heated machining were investigated as a means to allow for ductile mode machining, yet severe tool-wear and undesirable smearing limited the feasibility of these approaches. By using modified PCD cutting tools, high speed machining of porous tungsten at cutting speeds up to 400 m/min is achieved for the first time. Beyond a critical speed, brittle fracture and built-up edge are eliminated as the result of a brittle to ductile transition. A model of critical chip thickness ( hc ) effects based on cutting

  10. Assessment of Various Organic Matter Properties by Infrared Reflectance Spectroscopy of Sediments and Filters (United States)

    Alaoui, G.; Leger, M.; Gagne, J.; Tremblay, L.


    The goal of this work was to evaluate the capability of infrared reflectance spectroscopy for a fast quantification of the elemental and molecular compositions of sedimentary and particulate organic matter (OM). A partial least-squares (PLS) regression model was used for analysis and values were compared to those obtained by traditional methods (i.e., elemental, humic and HPLC analyses). PLS tools are readily accessible from software such as GRAMS (Thermo-Fisher) used in spectroscopy. This spectroscopic-chemometric approach has several advantages including its rapidity and use of whole unaltered samples. To predict properties, a set of infrared spectra from representative samples must first be fitted to form a PLS calibration model. In this study, a large set (180) of sediments and particles on GFF filters from the St. Lawrence estuarine system were used. These samples are very heterogenous (e.g., various tributaries, terrigenous vs. marine, events such as landslides and floods) and thus represent a challenging test for PLS prediction. For sediments, the infrared spectra were obtained with a diffuse reflectance, or DRIFT, accessory. Sedimentary carbon, nitrogen, humic substance contents as well as humic substance proportions in OM and N:C ratios were predicted by PLS. The relative root mean square error of prediction (%RMSEP) for these properties were between 5.7% (humin content) and 14.1% (total humic substance yield) using the cross-validation, or leave-one out, approach. The %RMSEP calculated by PLS for carbon content was lower with the PLS model (7.6%) than with an external calibration method (11.7%) (Tremblay and Gagné, 2002, Anal. Chem., 74, 2985). Moreover, the PLS approach does not require the extraction of POM needed in external calibration. Results highlighted the importance of using a PLS calibration set representative of the unknown samples (e.g., same area). For filtered particles, the infrared spectra were obtained using a novel approach based on

  11. Morphology and electronic properties of silicon carbide surfaces (United States)

    Nie, Shu


    Several issues related to SiC surfaces are studied in the thesis using scanning tunneling microscopy/spectroscopy (STM/S) and atomic force microscopy (AFM). Specific surfaces examined include electropolished SiC, epitaxial graphene on SiC, and vicinal (i.e. slightly miscut from a low-index direction) SiC that have been subjected to high temperature hydrogen-etching. The electropolished surfaces are meant to mimic electrochemically etched SiC, which forms a porous network. The chemical treatment of the surface is similar between electropolishing and electrochemical etching, but the etching conditions are slightly different such that the former produces a flat surface (that is amenable to STM study) whereas the latter produces a complex 3-dimensional porous network. We have used these porous SiC layers as semi-permeable membranes in a biosensor, and we find that the material is quite biocompatible. The purpose of the STM/STS study is to investigate the surface properties of the SiC on the atomic scale in an effort to explain this biocompatibility. The observed tunneling spectra are found to be very asymmetric, with a usual amount of current at positive voltages but no observable current at negative voltages. We propose that this behavior is due to surface charge accumulating on an incompletely passivated surface. Measurements on SiC surfaces prepared by various amounts of hydrogen-etching are used to support this interpretation. Comparison with tunneling computations reveals a density of about 10 13 cm-2 fixed charges on both the electro-polished and the H-etched surfaces. The relatively insulating nature observed on the electro-polished SiC surface may provide an explanation for the biocompatibility of the surface. Graphene, a monolayer of carbon, is a new material for electronic devices. Epitaxial graphene on SiC is fabricated by the Si sublimation method in which a substrate is heated up to about 1350°C in ultra-high vacuum (UHV). The formation of the graphene is

  12. Principal component analysis for surface reflection components and structure in facial images and synthesis of facial images for various ages (United States)

    Hirose, Misa; Toyota, Saori; Ojima, Nobutoshi; Ogawa-Ochiai, Keiko; Tsumura, Norimichi


    In this paper, principal component analysis is applied to the distribution of pigmentation, surface reflectance, and landmarks in whole facial images to obtain feature values. The relationship between the obtained feature vectors and the age of the face is then estimated by multiple regression analysis so that facial images can be modulated for woman aged 10-70. In a previous study, we analyzed only the distribution of pigmentation, and the reproduced images appeared to be younger than the apparent age of the initial images. We believe that this happened because we did not modulate the facial structures and detailed surfaces, such as wrinkles. By considering landmarks and surface reflectance over the entire face, we were able to analyze the variation in the distributions of facial structures and fine asperity, and pigmentation. As a result, our method is able to appropriately modulate the appearance of a face so that it appears to be the correct age.

  13. Effect of growth time on the surface and adhesion properties of Lactobacillus rhamnosus GG. (United States)

    Deepika, G; Green, R J; Frazier, R A; Charalampopoulos, D


    To investigate the changes in the surface properties of Lactobacillus rhamnosus GG during growth, and relate them with the ability of the Lactobacillus cells to adhere to Caco-2 cells. Lactobacillus rhamnosus GG was grown in complex medium, and cell samples taken at four time points and freeze dried. Untreated and trypsin treated freeze dried samples were analysed for their composition using SDS-PAGE analysis and Fourier transform infrared spectroscopy (FTIR), hydrophobicity and zeta potential, and for their ability to adhere to Caco-2 cells. The results suggested that in the case of early exponential phase samples (4 and 8 h), the net surface properties, i.e. hydrophobicity and charge, were determined to a large extent by anionic hydrophilic components, whereas in the case of stationary phase samples (13 and 26 h), hydrophobic proteins seemed to play the biggest role. Considerable differences were also observed between the ability of the different samples to adhere to Caco-2 cells; maximum adhesion was observed for the early stationary phase sample (13 h). The results suggested that the adhesion to Caco-2 cells was influenced by both proteins and non-proteinaceous compounds present on the surface of the Lactobacillus cells. The surface properties of Lact. rhamnosus GG changed during growth, which in return affected the ability of the Lactobacillus cells to adhere to Caco-2 cells. The levels of adhesion of Lactobacillus cells to Caco-2 cells were influenced by the growth time and reflected changes on the bacterial surface. This study provides critical information on the physicochemical factors that influence bacterial adhesion to intestinal cells.

  14. Electronic properties of semiconductor surfaces and metal/semiconductor interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Tallarida, M.


    This thesis reports investigations of the electronic properties of a semiconductor surface (silicon carbide), a reactive metal/semiconductor interface (manganese/silicon) and a non-reactive metal/semiconductor interface (aluminum-magnesium alloy/silicon). The (2 x 1) reconstruction of the 6H-SiC(0001) surface has been obtained by cleaving the sample along the (0001) direction. This reconstruction has not been observed up to now for this compound, and has been compared with those of similar elemental semiconductors of the fourth group of the periodic table. This comparison has been carried out by making use of photoemission spectroscopy, analyzing the core level shifts of both Si 2p and C 1s core levels in terms of charge transfer between atoms of both elements and in different chemical environments. From this comparison, a difference between the reconstruction on the Si-terminated and the C-terminated surface was established, due to the ionic nature of the Si-C bond. The growth of manganese films on Si(111) in the 1-5 ML thickness range has been studied by means of LEED, STM and photoemission spectroscopy. By the complementary use of these surface science techniques, two different phases have been observed for two thickness regimes (<1 ML and >1 ML), which exhibit a different electronic character. The two reconstructions, the (1 x 1)-phase and the ({radical}3 x {radical}3)R30 -phase, are due to silicide formation, as observed in core level spectroscopy. The growth proceeds via island formation in the monolayer regime, while the thicker films show flat layers interrupted by deep holes. On the basis of STM investigations, this growth mode has been attributed to strain due to lattice mismatch between the substrate and the silicide. Co-deposition of Al and Mg onto a Si(111) substrate at low temperature (100K) resulted in the formation of thin alloy films. By varying the relative content of both elements, the thin films exhibited different electronic properties

  15. Controllable surface morphology and properties via mist polymerization on a plasma-treated polymethyl methacrylate surface. (United States)

    Wan, S J; Wang, L; Xu, X J; Zhao, C H; Liu, X D


    Surface modification by grafting polymers on solid materials is an important strategy used to improve surface properties. This article reports that under appropriate conditions, very thin layers with desired morphologies may be constructed on a plasma-treated substrate by feeding a small quantity of a monomer with a mist stream carrying droplets produced from monomer solutions. We investigate the effects of process parameters that affect layer morphology, including exposure time to the mist stream, concentration of the monomer solution, and solvent selectivity. For a methyl methacrylate solution in ethanol, nanoparticles are uniformly grown with increasing monomer concentration or exposure time and finally form a porous layer at 3.65 mol L(-1) for 30 min. Decreasing solvent polarity not only affects surface morphology, but also increases hydrophobicity of the resulting surface. With 2,2,3,4,4,4-hexafluorobutyl methacrylate as the monomer, SEM and AFM micrographs indicated that mist polymerization results in numerous microspheres on the activated surface. These experimental results were interpreted by a mechanism in terms of an in situ polymerization accompanied by a phase transformation of the resulting polymer. Specifically, plasma treatment provides highly active cations and radicals to initiate very rapid polymerization, and the resulting polymers are consequently deposited from the liquid onto the surface under phase transition mechanisms.

  16. Electrical properties of Titan's surface from Cassini RADAR scatterometer measurements (United States)

    Wye, Lauren C.; Zebker, Howard A.; Ostro, Steven J.; West, Richard D.; Gim, Yonggyu; Lorenz, Ralph D.; The Cassini Radar Team


    albedo feature Shangri-La is best fit by a Hagfors model with a dielectric constant close to 2.4 and an rms slope near 9.5°. From the modeled backscatter curves, we find the average radar albedo in the same linear (SL) polarization to be near 0.34. We constrain the total-power albedo in order to compare the measurements with available groundbased radar results, which are typically obtained in both senses of circular polarization. We estimate an upper limit of 0.4 on the total-power albedo, a value that is significantly higher than the 0.21 total albedo value measured at 13 cm [Campbell, D., Black, G., Carter, L., Ostro, S., 2003. Science 302, 431-434]. This is consistent with a surface that has more small-scale structure and is thus more reflective at 2-cm than 13-cm. We compare results across overlapping observations and observe that the reduction and analysis are repeatable and consistent. We also confirm the strong correlations between radar and near-infrared images.

  17. Collimated light reflection and transmission of a surface partially covered by large and tenuous particles. (United States)

    Vázquez-Estrada, Omar; García-Valenzuela, Augusto


    We derive simple approximate expressions for the reflectivity and transmissivity of light from disordered monolayers of tenuous particles of dimensions larger than the wavelength and supported by a flat interface. The expressions derived can be used for different particle shapes and for moderate angles of incidence. We then investigate the effects of particle shape and orientation on reflectivity and transmissivity spectra of a monolayer of tenuous particles containing an optical chromophore in a solution in their interior. We also simulate the effects of a particle's shape and orientation on the angle dependence of the optical reflectivity and transmissivity. In our examples, we consider disordered monolayers of particles analogous to some biological cells.

  18. Preferential affinity of calcium ions to charged phosphatidic acid surface from a mixed calcium/barium solution: X-ray reflectivity and fluorescence studies. (United States)

    Bu, Wei; Flores, Kevin; Pleasants, Jacob; Vaknin, David


    X-ray reflectivity and fluorescence near total reflection experiments were performed to examine the affinities of divalent ions (Ca(2+) and Ba(2+)) from aqueous solution to a charged phosphatidic acid (PA) surface. A phospholipid (1,2-dimyristoyl-sn-glycero-3-phosphate, DMPA), spread as a monolayer at the air/water interface, was used to form and control the charge density at the interface. We find that, for solutions of the pure salts (i.e., CaCl(2) and BaCl(2)), the number of bound ions per DMPA at the interface is saturated at concentrations that exceed 10(-3) M. For 1:1 Ca(2+)/Ba(2+) mixed solutions, we find that the bound Ca(2+)/Ba(2+) ratio at the interface is 4:1. If the only property determining charge accumulation near PA were the ionic charges, the concentration of mixed Ca(2+)/Ba(2+) at the interface would equal that of the bulk. Our results show a clear specific affinity of PA for Ca compared to Ba. We provide some discussion on this issue as well as some implications for biological systems. Although our results indicate an excess of counterion charge with respect to the surface charge, that is, charge inversion, the analysis of both reflectivity and fluorescence do not reveal an excess of co-ions (namely, Cl(-) or I(-)).

  19. Measurements of the reflectance, contrast ratio, and scattering properties of digital micromirror devices (DMDs) (United States)

    Vorobiev, Dmitry; Travinsky, Anton; Quijada, Manuel A.; Ninkov, Zoran; Raisanen, Alan D.; Robberto, Massimo; Heap, Sara


    Digital micromirror devices (DMDs) are micro-electro- mechanical systems, originally developed to display images in projector systems. A DMD in the focal plane of an imaging system can be used as a reprogrammable slit mask of a multi-object spectrometer (MOS) by tilting some of the mirrors towards the spectrometer and tilting the rest of the mirrors away, thereby rejecting the unwanted light (due to the background and foreground objects). A DMD-based MOS can generate new, arbitrary slit patterns in seconds, which significantly reduces the overhead time during astronomical observations. Critically, DMD-based slit masks are extremely lightweight, compact and mechanically robust, which makes them attractive for use in space-based telescopes. As part of a larger effort to investigate the use of DMDs in space telescopes (sponsored by a NASA Strategic Astrophysics Technologies grant), we characterized the optical performance of Texas Instruments DMDs to determine their suitability for use in multi-object spectrometers. The performance of a DMD-based MOS is significantly affected by its optical throughput (reflectance), contrast ratio (the ability of the DMD to reject unwanted light) and scattering properties (which could lead to crosstalk and reduced signal-to-noise ratio in the spectrometer). We measured and quantified the throughput and contrast ratio of a Texas Instruments DMD in several configurations (which emulate the operation of a typical DMD-based MOS) and investigated the scattering properties of the individual DMD mirrors. In this work we present the results of our analysis, describe the performance of a typical DMD- based MOS and discuss the practical limitations of these instruments (such as maximum density of sources and expected signal-to- noise ratio).

  20. Yttrium ion implantation on the surface properties of magnesium

    International Nuclear Information System (INIS)

    Wang, X.M.; Zeng, X.Q.; Wu, G.S.; Yao, S.S.


    Owing to their excellent physical and mechanical properties, magnesium and its alloys are receiving more attention. However, their application has been limited to the high reactivity and the poor corrosion resistance. The aim of the study was to investigate the beneficial effects of ion-implanted yttrium using a MEVVA ion implanter on the surface properties of pure magnesium. Isothermal oxidation tests in pure O 2 at 673 and 773 K up to 90 min indicated that the oxidation resistance of magnesium had been significantly improved. Surface morphology of the oxide scale was analyzed using scanning electron microscope (SEM). Auger electron spectroscopy (AES) and X-ray diffraction (XRD) analyses indicated that the implanted layer was mainly composed of MgO and Y 2 O 3 , and the implanted layer with a duplex structure could decrease the inward diffusion of oxygen and reduce the outward diffusion of Mg 2+ , which led to improving the oxidation resistance of magnesium. Potentiodynamic polarization curves were used to evaluate the corrosion resistance of the implanted magnesium. The results show yttrium implantation could enhance the corrosion resistance of implanted magnesium compared with that of pure magnesium

  1. Improved antifouling properties of photobioreactors by surface grafted sulfobetaine polymers. (United States)

    Wang, Dongwei; Wu, Xia; Long, Lixia; Yuan, Xubo; Zhang, Qinghua; Xue, Shengzhang; Wen, Shumei; Yan, Chenghu; Wang, Jianming; Cong, Wei


    To improve the antifouling (AF) properties of photobioreactors (PBR) for microalgal cultivation, using trihydroxymethyl aminomethane (tris) as the linking agent, a series of polyethylene (PE) films grafted with sulfobetaine (PE-SBMA) with grafting density ranging from 23.11 to 112 μg cm -2 were prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). It was found that the contact angle of PE-SBMA films decreased with the increase in the grafting density. When the grafting density was 101.33 μg cm -2 , it reached 67.27°. Compared with the PE film, the adsorption of protein on the PE-SBMA film decreased by 79.84% and the total weight of solid and absorbed microalgae decreased by 54.58 and 81.69%, respectively. Moreover, the transmittance of PE-SBMA film recovered to 86.03% of the initial value after cleaning, while that of the PE film recovered to only 47.27%. The results demonstrate that the AF properties of PE films were greatly improved on polySBMA-grafted surfaces.

  2. Surface structure, crystallographic and ice-nucleating properties of cellulose (United States)

    Hiranuma, Naruki; Möhler, Ottmar; Kiselev, Alexei; Saathoff, Harald; Weidler, Peter; Shutthanandan, Shuttha; Kulkarni, Gourihar; Jantsch, Evelyn; Koop, Thomas


    Increasing evidence of the high diversity and efficient freezing ability of biological ice-nucleating particles is driving a reevaluation of their impact upon climate. Despite their potential importance, little is known about their atmospheric abundance and ice nucleation efficiency, especially non-proteinaceous ones, in comparison to non-biological materials (e.g., mineral dust). Recently, microcrystalline cellulose (MCC; non-proteinaceous plant structural polymer) has been identified as a potential biological ice-nucleating particle. However, it is still uncertain if the ice-nucleating activity is specific to the MCC structure or generally relevant to all cellulose materials, such that the results of MCC can be representatively scaled up to the total cellulose content in the atmosphere to address its role in clouds and the climate system. Here we use the helium ion microscopy (HIM) imaging and the X-ray diffraction (XRD) technique to characterize the nanoscale surface structure and crystalline properties of the two different types of cellulose (MCC and fibrous cellulose extracted from natural wood pulp) as model proxies for atmospheric cellulose particles and to assess their potential accessibility for water molecules. To complement these structural characterizations, we also present the results of immersion freezing experiments using the cold stage-based droplet freezing BINARY (Bielefeld Ice Nucleation ARaY) technique. The HIM results suggest that both cellulose types have a complex porous morphology with capillary spaces between the nanoscale fibrils over the microfiber surface. These surface structures may make cellulose accessible to water. The XRD results suggest that the structural properties of both cellulose materials are in agreement (i.e., P21 space group; a=7.96 Å, b=8.35 Å, c=10.28 Å) and comparable to the crystallographic properties of general monoclinic cellulose (i.e., Cellulose Iβ). The results obtained from the BINARY measurements suggest

  3. Surface-atmosphere interactions with coupled within-canopy aerodynamic resistance and canopy reflection. (United States)

    Timmermans, J.; van der Tol, C.; Verhoef, W.; Su, Z.


    Models that describe the exchange of CO2 and H2O between the surface and atmosphere use bulk-parametrization of the within-canopy aerodynamic resistance and leaf area density (eq. LAI). This bulk parametrization is based on the Monin-Obukhov Similarity (MOS) theory. The MOS theory however breaks down for sparse canopies and it cannot couple profiles in the leaf density to profiles in the within-canopy aerodynamic resistance. The objective of this research is to create a simple model that is able to couple the within-canopy aerodynamic resistance and canopy reflection for different levels in the canopy. This model should be able to represent the canopy using as fewer parameters as possible, in order to facilitate inversion of remote sensing imagery. A virtual canopy was simulated using an L-systems approach, Lindenmayer 1968. The L-system approach was chosen because it describes the canopy with fractals. It therefore needs very little inputs to simulate a virtual canopy. A vertical profile of leaf density was calculated for 60 levels from this virtual canopy. The within-canopy aerodynamic resistance was modeled from the vertical leaf density profile using foliage drag coefficient, Massman 1997. A modified version of the SCOPE (Soil Canopy Observations and Photosynthesis) model was used to calculate the H2O and CO2 fluxes using the vertical profiles of leaf density and within-canopy aerodynamic resistance. The simulated fluxes are compared with field measurements over a vineyard and a forested area. The field measurements in both areas are acquired using the same setup: a basic flux tower in addition with an eddy-covariance setup. We present in this article the methodology and the results, as a proof of concept. references Massman, W.J., An Analytical One-Dimensional Model of Momentum Transfer by vegetation of arbitrary structure, Boundary-Layer Meteorology, 1997, 83, 407-421 Lindenmayer, A., Mathematical Models for Cellular Interactions in Development, Journal of

  4. Surface properties, solubility and dissolution kinetics of bamboo phytoliths (United States)

    Fraysse, Fabrice; Pokrovsky, Oleg S.; Schott, Jacques; Meunier, Jean-Dominique


    Although phytoliths, constituted mainly by micrometric opal, exhibit an important control on silicon cycle in superficial continental environments, their thermodynamic properties and reactivity in aqueous solution are still poorly known. In this work, we determined the solubility and dissolution rates of bamboo phytoliths collected in the Réunion Island and characterized their surface properties via electrophoretic measurements and potentiometric titrations in a wide range of pH. The solubility product of "soil" phytoliths ( pKsp0=2.74 at 25 °C) is equal to that of vitreous silica and is 17 times higher than that of quartz. Similarly, the enthalpy of phytoliths dissolution reaction (ΔHr25-80°C=10.85kJ/mol) is close to that of amorphous silica but is significantly lower than the enthalpy of quartz dissolution. Electrophoretic measurements yield isoelectric point pH IEP = 1.2 ± 0.1 and 2.5 ± 0.2 for "soil" (native) and "heated" (450 °C heating to remove organic matter) phytoliths, respectively. Surface acid-base titrations allowed generation of a 2-p K surface complexation model. Phytoliths dissolution rates, measured in mixed-flow reactors at far from equilibrium conditions at 2 ⩽ pH ⩽ 12, were found to be intermediate between those of quartz and vitreous silica. The dissolution rate dependence on pH was modeled within the concept of surface coordination theory using the equation: R=k1·{>SiOH2+}n+k2·{>SiOH0}+k3·{>SiO-}m, where {> i} stands for the concentration of the surface species present at the SiO 2-H 2O interface, ki are the rate constants of the three parallel reactions and n and m represent the order of the proton- and hydroxy-promoted reactions, respectively. It follows from the results of this study that phytoliths dissolution rates exhibit a minimum at pH ˜ 3. This can explain their good preservation in the acidic soil horizons of Réunion Island. In terms of silicon biogeochemical cycle, phytoliths represent a large buffering reservoir

  5. Surface properties of SAR11 bacteria facilitate grazing avoidance. (United States)

    Dadon-Pilosof, Ayelet; Conley, Keats R; Jacobi, Yuval; Haber, Markus; Lombard, Fabien; Sutherland, Kelly R; Steindler, Laura; Tikochinski, Yaron; Richter, Michael; Glöckner, Frank Oliver; Suzuki, Marcelino T; West, Nyree J; Genin, Amatzia; Yahel, Gitai


    Oceanic ecosystems are dominated by minute microorganisms that play a major role in food webs and biogeochemical cycles 1 . Many microorganisms thrive in the dilute environment due to their capacity to locate, attach to, and use patches of nutrients and organic matter 2,3 . We propose that some free-living planktonic bacteria have traded their ability to stick to nutrient-rich organic particles for a non-stick cell surface that helps them evade predation by mucous filter feeders. We used a combination of in situ sampling techniques and next-generation sequencing to study the biological filtration of microorganisms at the phylotype level. Our data indicate that some marine bacteria, most notably the highly abundant Pelagibacter ubique and most other members of the SAR 11 clade of the Alphaproteobacteria, can evade filtration by slipping through the mucous nets of both pelagic and benthic tunicates. While 0.3 µm polystyrene beads and other similarly-sized bacteria were efficiently filtered, SAR11 members were not captured. Reversed-phase chromatography revealed that most SAR11 bacteria have a much less hydrophobic cell surface than that of other planktonic bacteria. Our data call for a reconsideration of the role of surface properties in biological filtration and predator-prey interactions in aquatic systems.

  6. Identification of rheological properties of human body surface tissue. (United States)

    Benevicius, Vincas; Gaidys, Rimvydas; Ostasevicius, Vytautas; Marozas, Vaidotas


    According to World Health Organization obesity is one of the greatest public health challenges of the 21st century. It has tripled since the 1980s and the numbers of those affected continue to rise at an alarming rate, especially among children. There are number of devices that act as a prevention measure to boost person's motivation for physical activity and its levels. The placement of these devices is not restricted thus the measurement errors that appear because of the body rheology, clothes, etc. cannot be eliminated. The main objective of this work is to introduce a tool that can be applied directly to process measured accelerations so human body surface tissue induced errors can be reduced. Both the modeling and experimental techniques are proposed to identify body tissue rheological properties and prelate them to body mass index. Multi-level computational model composed from measurement device model and human body surface tissue rheological model is developed. Human body surface tissue induced inaccuracies can increase the magnitude of measured accelerations up to 34% when accelerations of the magnitude of up to 27 m/s(2) are measured. Although the timeframe of those disruptions are short - up to 0.2 s - they still result in increased overall measurement error. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Optical properties of WO{sub 3} thin films using surface plasmon resonance technique

    Energy Technology Data Exchange (ETDEWEB)

    Paliwal, Ayushi; Sharma, Anjali; Gupta, Vinay, E-mail:, E-mail: [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Tomar, Monika [Department of Physics, Miranda House, University of Delhi, Delhi 110007 (India)


    Indigenously assembled surface plasmon resonance (SPR) technique has been exploited to study the thickness dependent dielectric properties of WO{sub 3} thin films. WO{sub 3} thin films (80 nm to 200 nm) have been deposited onto gold (Au) coated glass prism by sputtering technique. The structural, optical properties and surface morphology of the deposited WO{sub 3} thin films were studied using X-ray diffraction, UV-visible spectrophotometer, Raman spectroscopy, and Scanning electron microscopy (SEM). XRD analysis shows that all the deposited WO{sub 3} thin films are exhibiting preferred (020) orientation and Raman data indicates that the films possess single phase monoclinic structure. SEM images reveal the variation in grain size with increase in thickness. The SPR reflectance curves of the WO{sub 3}/Au/prism structure were utilized to estimate the dielectric properties of WO{sub 3} thin films at optical frequency (λ = 633 nm). As the thickness of WO{sub 3} thin film increases from 80 nm to 200 nm, the dielectric constant is seen to be decreasing from 5.76 to 3.42, while the dielectric loss reduces from 0.098 to 0.01. The estimated value of refractive index of WO{sub 3} film is in agreement to that obtained from UV-visible spectroscopy studies. The strong dispersion in refractive index is observed with wavelength of incident laser light.

  8. Kaguya observations of the lunar wake in the terrestrial foreshock: Surface potential change by bow-shock reflected ions (United States)

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


    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.

  9. Monitoring polymer properties using shear horizontal surface acoustic waves. (United States)

    Gallimore, Dana Y; Millard, Paul J; Pereira da Cunha, Mauricio


    Real-time, nondestructive methods for monitoring polymer film properties are increasingly important in the development and fabrication of modern polymer-containing products. Online testing of industrial polymer films during preparation and conditioning is required to minimize material and energy consumption, improve the product quality, increase the production rate, and reduce the number of product rejects. It is well-known that shear horizontal surface acoustic wave (SH-SAW) propagation is sensitive to mass changes as well as to the mechanical properties of attached materials. In this work, the SH-SAW was used to monitor polymer property changes primarily dictated by variations in the viscoelasticity. The viscoelastic properties of a negative photoresist film were monitored throughout the ultraviolet (UV) light-induced polymer cross-linking process using SH-SAW delay line devices. Changes in the polymer film mass and viscoelasticity caused by UV exposure produced variations in the phase velocity and attenuation of the SH-SAW propagating in the structure. Based on measured polymer-coated delay line scattering transmission responses (S(21)) and the measured polymer layer thickness and density, the viscoelastic constants c(44) and eta(44) were extracted. The polymer thickness was found to decrease 0.6% during UV curing, while variations in the polymer density were determined to be insignificant. Changes of 6% in c(44) and 22% in eta(44) during the cross-linking process were observed, showing the sensitivity of the SH-SAW phase velocity and attenuation to changes in the polymer film viscoelasticity. These results indicate the potential for SH-SAW devices as online monitoring sensors for polymer film processing.

  10. 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.


    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

  11. Micromechanical and surface adhesive properties of single saccharomyces cerevisiae cells (United States)

    Farzi, Bahman; Cetinkaya, Cetin


    The adhesion and mechanical properties of a biological cell (e.g. cell membrane elasticity and adhesiveness) are often strong indicators for the state of its health. Many existing techniques for determining mechanical properties of cells require direct physical contact with a single cell or a group of cells. Physical contact with the cell can trigger complex mechanotransduction mechanisms, leading to cellular responses, and consequently interfering with measurement accuracy. In the current work, based on ultrasonic excitation and interferometric (optical) motion detection, a non-contact method for characterizing the adhesion and mechanical properties of single cells is presented. It is experimentally demonstrated that the rocking (rigid body) motion and internal vibrational resonance frequencies of a single saccharomyces cerevisiae (SC) (baker’s yeast) cell can be acquired with the current approach, and the Young’s modulus and surface tension of the cell membrane as well as surface adhesion energy can be extracted from the values of these acquired resonance frequencies. The detected resonance frequency ranges for single SC cells include a rocking (rigid body) frequency of 330  ±  70 kHz and two breathing resonance frequencies of 1.53  ±  0.12 and 2.02  ±  0.31 MHz. Based on these values, the average work-of-adhesion of SC cells on a silicon substrate in aqueous medium is extracted, for the first time, as WASC-Si=16.2+/- 3.8 mJ {{m}-2} . Similarly, the surface tension and the Young’s modulus of the SC cell wall are predicted as {{σ }SC}=0.16+/- 0.02 N {{m}-1} and {{E}SC}= 9.20  ±  2.80 MPa, respectively. These results are compared to those reported in the literature by utilizing various methods, and good agreements are found. The current approach eliminates the measurement inaccuracies associated with the physical contact. Exciting and detecting cell dynamics at micro-second time-scales is significantly faster than the

  12. Analysis of bacteria on steel surfaces using reflectance micro-Fourier transform infrared spectroscopy. (United States)

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


    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.

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

    DEFF Research Database (Denmark)

    Rindel, Jens Holger


    The author’s research on reflectors over nearly 25 years is summarized. The influence of curvature was analyzed by a geometrical model in order to quantify the attenuation by a simple expression. Reflection from a finite size plate was studied using the Kirchhoff-Fresnel approximation and the des......The author’s research on reflectors over nearly 25 years is summarized. The influence of curvature was analyzed by a geometrical model in order to quantify the attenuation by a simple expression. Reflection from a finite size plate was studied using the Kirchhoff-Fresnel approximation...... in the refurbishment of the concert hall of the Danish Radio in Copenhagen 1989, and later in many other halls. In order to describe the scattering due to edge diffraction the directional characteristic of reflections from a finite-size plate has been studied and a simple approximation valid for octave bands has been...

  14. Optical properties and surface morphology studies of palladium contacts on mercuric iodide single crystals

    Energy Technology Data Exchange (ETDEWEB)

    George, M.A.; Azoulay, M.; Burger, A.; Biao, Y.; Silberman, E. [Fisk Univ., Nashville, TN (United States). Dept. of Physics; Nason, D. [EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations


    Palladium is chemically suitable for electric contacts on mercuric iodide detectors for photon and nuclear radiation detection, so the understanding of palladium contacts is important for fundamental and practical scientific purposes. A study has been conducted on the surface morphology of evaporated contacts using Atomic Force Microscopy (AFM) and optical transmission and reflection. Evaporated palladium coatings are typically nonuniform and may deposit selectively on mercuric iodide surface defects. Reflection measurements show that coating thickness and surface treatment affect intensity, position and shape of a reflected peak characteristic of the mercuric iodide structure. Results indicate that the band gap energy in the surface of the mercuric iodide is lowered by palladium contacts.

  15. 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


    Theoretical calculations and experimental studies were carried out on polyurethane (PU)–TiO2 composite coatings on bright and matte aluminium surfaces with an aim to understand and tailor the light scattering from particles incorporated into an anodised layer for designing the optical appearance...... 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...

  16. European spruce bark beetle (Ips typographus, L.) green attack affects foliar reflectance and biochemical properties (United States)

    Abdullah, Haidi; Darvishzadeh, Roshanak; Skidmore, Andrew K.; Groen, Thomas A.; Heurich, Marco


    The European spruce bark beetle Ips typographus, L. (hereafter bark beetle), causes major economic loss to the forest industry in Europe, especially in Norway Spruce (Picea abies). To minimise economic loss and preclude a mass outbreak, early detection of bark beetle infestation (so-called ;green attack; stage - a period at which trees are yet to show visual signs of infestation stress) is, therefore, a crucial step in the management of Norway spruce stands. It is expected that a bark beetle infestation at the green attack stage affects a tree's physiological and chemical status. However, the concurrent effect on key foliar biochemical such as foliar nitrogen and chlorophyll as well as spectral responses are not well documented in the literature. Therefore, in this study, the early detection of bark beetle green attacks is investigated by examining foliar biochemical and spectral properties (400-2000 nm). We also assessed whether bark beetle infestation affects the estimation accuracy of foliar biochemicals. An extensive field survey was conducted in the Bavarian Forest National Park (BFNP), Germany, in the early summer of 2015 to collect leaf samples from 120 healthy and green attacked trees. The spectra of the leaf samples were measured using an ASD FieldSpec3 equipped with an integrating sphere. Significant differences (p < 0.05) between healthy and infested needle samples were found in the mean reflectance spectra, with the most pronounced differences being observed in the NIR and SWIR regions between 730 and 1370 nm. Furthermore, significant differences (p < 0.05) were found in the biochemical compositions (chlorophyll and nitrogen concentration) of healthy versus green attacked samples. Our results further demonstrate that the estimation accuracy of foliar chlorophyll and nitrogen concentrations, utilising partial least square regression model, was lower for the infested compared to the healthy trees. We show that early stage of infestation reduces not only

  17. Interactions of satellite-speed helium atoms with satellite-surfaces. 1. Spatial distributions of reflected helium atoms

    International Nuclear Information System (INIS)

    Liu, S.M.; Rodgers, W.E.; Knuth, E.L.


    Interactions of satellite-speed helium atoms with practical satellite surfaces were investigated experimentally, and spatial distributions of satellite-speed helium beams scattered from four different engineering surfaces were measured. The 7000-m/s helium beams were produced using an arc-heated supersonic molecular beam source. The test surfaces included cleaned 6061-T6 aluminum plate, anodized aluminum foil, white paint, and quartz surfaces. Both in-plane (in the plane containing the incident beam and the surface normal) and out-of-plane spatial distributions of reflected helium atoms were measured for six different incidence angles (0, 15, 30, 45, 60, and 75 deg from the surface normal). It was found that a large fraction of the incident helium atoms were scattered back in the vicinity of the incoming beam, particularly in the case of glancing incidence angles. This unexpected scattering feature results perhaps from the gross roughness of these test surfaces. This prominent backscattering could yield drag coefficients which are higher than for surfaces with either forward-lobed or diffusive (cosine) scattering patterns

  18. Analysis of human perception of facial skin radiance by means of image histogram parameters of surface and subsurface reflections from the skin. (United States)

    Matsubara, Akira; Liang, Zhiwu; Sato, Yuji; Uchikawa, Keiji


    The appearance of the skin is the result of complicated light-skin interactions involving surface and subsurface reflections. Radiant skin is a complicated attribute but is important for skin beauty. The aim of the present study was to achieve an understanding of the association between human perceptions of skin radiance and image histogram parameters from technically recorded images of surface and subsurface reflections. Facial images of 45 subjects were evaluated visually by 30 respondents and were also computer analyzed in terms of their image histogram parameters. A partial least squares regression model was created to explain visual perceptions in terms of the image histogram parameters. Visual perceptions of subsurface reflections can be explained in terms of the mean from the subsurface reflection image histogram, and visual perceptions of surface reflections can be explained in terms of the standard deviation (SD) and skewness from the surface reflection image histogram. Skin radiance can be explained in terms of the mean from the subsurface reflection and the SD from the surface reflection. To acquire skin radiance, a surface reflection component that makes the skin look shiny and a subsurface reflection component that is in line with skin fairness are both needed. A balance of these features provides the origin of skin radiance. © 2011 John Wiley & Sons A/S.

  19. A decade of silicone hydrogel development: surface properties, mechanical properties, and ocular compatibility. (United States)

    Tighe, Brian J


    Since the initial launch of silicone hydrogel lenses, there has been a considerable broadening in the range of available commercial material properties. The very mobile silicon-oxygen bonds convey distinctive surface and mechanical properties on silicone hydrogels, in which advantages of enhanced oxygen permeability, reduced protein deposition, and modest frictional interaction are balanced by increased lipid and elastic response. There are now some 15 silicone hydrogel material variants available to practitioners; arguably, the changes that have taken place have been strongly influenced by feedback based on clinical experience. Water content is one of the most influential properties, and the decade has seen a progressive rise from lotrafilcon-A (24%) to efrofilcon-A (74%). Moduli have decreased over the same period from 1.4 to 0.3 MPa, but not solely as a result of changes in water content. Surface properties do not correlate directly with water content, and ingenious approaches have been used to achieve desirable improvements (e.g., greater lubricity and lower contact angle hysteresis). This is demonstrated by comparing the hysteresis value of the earliest (lotrafilcon-A, >40°) and most recent (delefilcon-A, silicone hydrogels. Although wettability is important, it is not of itself a good predictor of ocular response because this involves a much wider range of physicochemical and biochemical factors. The interference of the lens with ocular dynamics is complex leading separately to tissue-material interactions involving anterior and posterior lens surfaces. The biochemical consequences of these interactions may hold the key to a greater understanding of ocular incompatibility and end of day discomfort.

  20. 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: [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)


    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.

  1. Critical and creative reflective inquiry: surfacing narratives to enable learning and inform action

    NARCIS (Netherlands)

    Rn, MscN Shaun Cardiff


    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

  2. 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.


    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

  3. 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


    rotating it 90 degrees around its normal axis. We build an analytic anisotropic reflectance model based on the microstructure engineered to obtain such contrast. Using our model to render synthetic images, we predict the above mentioned contrasts and compare our predictions with the measurements reported...

  4. Effect of surface energy of solid surfaces on the micro- and macroscopic properties of adsorbed BSA and lysozyme. (United States)

    Sharma, Indu; Pattanayek, Sudip K


    The surface energy, a macroscopic property, depends on the chemical functionality and micro- and macroscopic roughness of the surface. The adsorption of two widely used proteins bovine serum albumin (BSA) and lysozyme on surfaces of four different chemical functionalities were done to find out the interrelation between macroscopic and microscopic properties. We have observed the secondary structure of protein after its adsorption. In addition, we observed the variation of surface energy of proteins due to variation in adsorption time, change in protein concentration and effect of a mixture of proteins. Surfaces of three different chemical functionalities namely, amine, hydroxyl and octyl were obtained through self-assembled monolayer on silica surfaces and were tested for responses towards adsorption of lysozyme and BSA. The adsorbed lysozyme has higher surface energy than the adsorbed BSA on amine and octyl surfaces. On hydroxyl functional surface, the surface energy due to the adsorbed lysozyme or BSA increases slowly with time. The surface energy of the adsorbed protein increases gradually with increasing protein concentration on hydrophobic surfaces. On hydrophilic surfaces, with increasing BSA concentration in bulk solution, the surface energy of the adsorbed protein on GPTMS and amine surfaces is maximum at 1μM concentration. During the adsorption from a mixture of BSA and lysozyme on octyl surface, first lysozyme adsorbs and subsequent BSA adsorption leads to a high surface energy. Copyright © 2016. Published by Elsevier B.V.

  5. Measuring and modeling the effect of surface moisture on the spectral reflectance of coastal beach sand

    NARCIS (Netherlands)

    Nolet, Corjan; Poortinga, Ate; Roosjen, Peter; Bartholomeus, Harm; Ruessink, Gerben|info:eu-repo/dai/nl/169093360


    Surface moisture is an important supply limiting factor for aeolian sand transport, which is the primary driver of coastal dune development. As such, it is critical to account for the control of surface moisture on available sand for dune building. Optical remote sensing has the potential to measure

  6. Adaptive Surface Modeling of Soil Properties in Complex Landforms

    Directory of Open Access Journals (Sweden)

    Wei Liu


    Full Text Available Abstract: Spatial discontinuity often causes poor accuracy when a single model is used for the surface modeling of soil properties in complex geomorphic areas. Here we present a method for adaptive surface modeling of combined secondary variables to improve prediction accuracy during the interpolation of soil properties (ASM-SP. Using various secondary variables and multiple base interpolation models, ASM-SP was used to interpolate soil K+ in a typical complex geomorphic area (Qinghai Lake Basin, China. Five methods, including inverse distance weighting (IDW, ordinary kriging (OK, and OK combined with different secondary variables (e.g., OK-Landuse, OK-Geology, and OK-Soil, were used to validate the proposed method. The mean error (ME, mean absolute error (MAE, root mean square error (RMSE, mean relative error (MRE, and accuracy (AC were used as evaluation indicators. Results showed that: (1 The OK interpolation result is spatially smooth and has a weak bull's-eye effect, and the IDW has a stronger ‘bull’s-eye’ effect, relatively. They both have obvious deficiencies in depicting spatial variability of soil K+. (2 The methods incorporating combinations of different secondary variables (e.g., ASM-SP, OK-Landuse, OK-Geology, and OK-Soil were associated with lower estimation bias. Compared with IDW, OK, OK-Landuse, OK-Geology, and OK-Soil, the accuracy of ASM-SP increased by 13.63%, 10.85%, 9.98%, 8.32%, and 7.66%, respectively. Furthermore, ASM-SP was more stable, with lower MEs, MAEs, RMSEs, and MREs. (3 ASM-SP presents more details than others in the abrupt boundary, which can render the result consistent with the true secondary variables. In conclusion, ASM-SP can not only consider the nonlinear relationship between secondary variables and soil properties, but can also adaptively combine the advantages of multiple models, which contributes to making the spatial interpolation of soil K+ more reasonable.

  7. Study of Surface Wettability Change of Unconsolidated Sand Using Diffuse Reflectance Infrared Fourier Transform Spectroscopy and Thermogravimetric Analysis. (United States)

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


    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.

  8. Directional reflectance factors for monitoring spatial changes in soil surface structure and soil organic matter erosion in agricultural systems (United States)

    Croft, H.; Anderson, K.


    Soils can experience rapid structural degradation in response to land cover changes, resulting in reduced soil productivity, increased erodibility and a loss of soil organic matter (SOM). The breakdown of soil aggregates through slaking and raindrop impact is linked to organic matter turnover, with subsequently eroded material often displaying proportionally more SOM. A reduction in aggregate stability is reflected in a decline in soil surface roughness (SSR), indicating that a soil structural change can be used to highlight soil vulnerability to SOM loss through mineralisation or erosion. Accurate, spatially-continuous measurements of SSR are therefore needed at a variety of spatial and temporal scales to understand the spatial nature of SOM erosion and deposition. Remotely-sensed data can provide a cost-effective means of monitoring changes in soil surface condition over broad spatial extents. Previous work has demonstrated the ability of directional reflectance factors to monitor soil crusting within a controlled laboratory experiment, due to changes in the levels of self-shadowing effects by soil aggregates. However, further research is needed to test this approach in situ, where other soil variables may affect measured reflectance factors and to investigate the use of directional reflectance factors for monitoring soil erosion processes. This experiment assesses the potential of using directional reflectance factors to monitor changes in SSR, aggregate stability and soil organic carbon (SOC) content for two agricultural conditions. Five soil plots representing tilled and seedbed soils were subjected to different durations of natural rainfall, producing a range of different levels of SSR. Directional reflectance factors were measured concomitantly with sampling for soil structural and biochemical tests at each soil plot. Soil samples were taken to measure aggregate stability (wet sieving), SOC (loss on ignition) and soil moisture (gravimetric method). SSM

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

    KAUST Repository

    Yao, Yuan


    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.

  10. 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

    of elastic symmetry are obtained in terms of the direction cosines of the propagation vector. It is shown that ... In general, the particle motion is neither ... qP waves at the plane free boundary of a mon- oclinic half-space. In a subsequent paper, Chat- topadhyay et al (1996) studied the reflection of. qSV waves. Since, in both of ...

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

    CERN Document Server

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


    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.

  12. Gravimetric and density profiling using the combination of surface acoustic waves and neutron reflectivity. (United States)

    Toolan, Daniel T W; Barker, Robert; Gough, Tim; Topham, Paul D; Howse, Jonathan R; Glidle, Andrew


    A new approach is described herein, where neutron reflectivity measurements that probe changes in the density profile of thin films as they absorb material from the gas phase have been combined with a Love wave based gravimetric assay that measures the mass of absorbed material. This combination of techniques not only determines the spatial distribution of absorbed molecules, but also reveals the amount of void space within the thin film (a quantity that can be difficult to assess using neutron reflectivity measurements alone). The uptake of organic solvent vapours into spun cast films of polystyrene has been used as a model system with a view to this method having the potential for extension to the study of other systems. These could include, for example, humidity sensors, hydrogel swelling, biomolecule adsorption or transformations of electroactive and chemically reactive thin films. This is the first ever demonstration of combined neutron reflectivity and Love wave-based gravimetry and the experimental caveats, limitations and scope of the method are explored and discussed in detail. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Investigation of physical properties and surface morphology of Cu nanolayer deposited on glass and (Al, Fe) thin films by DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, P.A. [Islamic Azad Univ., North Tehran (Iran, Islamic Republic of). Dept. of Chemistry; Islamic Azad Univ., Tabriz (Iran, Islamic Republic of). Dept. of Science-Applied Chemistry; Laheghi, S.N.; Ghoranneviss, M. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Plasma Research Center; Moradi, S. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Chemistry; Aberumand, P. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Science and Research Laboratory Complex


    The applications for copper (Cu) thin films with micro or nanostructural dimensions range from catalysis to microelectronic devices. This paper reported on a study in which DC magnetron sputtering was used to coat iron (Fe), copper (Cu) and aluminum (Al) on glass substrate under a particular voltage, time and optimized deposition pressure. The samples were then coated with Cu using the same technique in preparation of different multilayers. Physical properties such as transmission and reflection per cent, magnetic and electrical properties, size and surface morphology were analyzed using data from AFM, XRD, SEM, Four point probe, and magneto resistive spectrophotometers. The study showed that the size, surface morphology and some physical properties of Cu nanolayer depend on substrate materials, surface morphology and physical properties below the nanolayer. Future work will focus on chemical properties such as catalytic and electrochemical properties. Copper nanoparticles will also be synthesized on other materials such as ZnO. 14 refs., 1 tab., 3 figs.

  14. Designed cellulose nanocrystal surface properties for improving barrier properties in polylactide nanocomposites. (United States)

    Espino-Pérez, Etzael; Bras, Julien; Almeida, Giana; Plessis, Cédric; Belgacem, Naceur; Perré, Patrick; Domenek, Sandra


    Nanocomposites are an opportunity to increase the performance of polymer membranes by fine-tuning their morphology. In particular, the understanding of the contribution of the polymer matrix/nanofiller interface to the overall transport properties is key to design membranes with tailored selective and adsorptive properties. In that aim, cellulose nanocrystals (CNC)/polylactide (PLA) nanocomposites were fabricated with chemically designed interfaces, which were ensuring the compatibility between the constituents and impacting the mass transport mechanism. A detailed analysis of the mass transport behaviour of different permeants in CNC/PLA nanocomposites was carried out as a function of their chemical affinity to grafted CNC surfaces. Penetrants (O 2 and cyclohexane), which were found to slightly interact with the constituents of the nanocomposites, provided information on the small tortuosity effect of CNC on diffusive mass transport. The mass transport of water (highly interacting with CNC) and anisole (interacting only with designed CNC surfaces) exhibited non-Fickian, Case II behaviour. The water vapour caused significant swelling of the CNC, which created a preferential pathway for mass transport. CNC surface grafting could attenuate this phenomenon and decrease the water transport rate. Anisole, an aromatic organic vapour, became reversibly trapped at the specifically designed CNC/PLA interface, but without any swelling or creation of an accelerated pathway. This caused the decrease of the overall mass transport rate. The latter finding could open a way to the creation of materials with specifically designed barrier properties by designing nanocomposites interfaces with specific interactions towards permeants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Influence of surface PMPC brushes on tribological and biocompatibility properties of UHMWPE (United States)

    Xiong, Dangsheng; Deng, Yaling; Wang, Nan; Yang, Yuanyuan


    Extremely efficient lubrication has been observed between natural joint surfaces and the friction coefficients can reach as low as 0.001. However, attaining the ultra-low friction coefficients between articulating cartilage surfaces in any artificial joints remains a challenge for bio-tribologists. In order to obtain the ultra-low friction coefficients as in natural joints, a biomimetic zwitterionic monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) was grafted on the ultra high molecular weight polyethylene (UHMWPE) by UV radiation and self-polymerized to form brush-like structure. The results of total reflection (FT-IR/ATR) spectra and X-ray photoelectron spectroscopy (XPS) spectra indicated successful grafting of PMPC on to the UHMWPE surface (Polymerization of 2-methacryloyloxyethyl phosphorylcholine). The water contact angle of UHMWPE decreased from 80° to 15° after grafting PMPC for 45 min. Tribological properties were tested under high contact stress for a longer duration of time. The friction coefficient of the sample grafted with PMPC was found to be much lower than that of untreated UHMWPE at initial stage which increased gradually with the increase of the cycle till it attained the same level as that observed for untreated UHMWPE. The wear rate of modified samples was decreased by 37% and 46% in distilled water and saline, respectively. The highly hydrated PMPC layer provided efficient lubrication at the interface between the sliding couple leading to wear reduction of UHMWPE. Furthermore, blood compatibility of modified artificial joint materials was improved significantly, which has been attributed to the properties and structures of PMPC grafted on the UHMWPE surface.

  16. Calculated Fermi surface properties of LaSn3 and YSn3 under pressure

    International Nuclear Information System (INIS)

    Kanchana, V.


    The electronic structure, Fermi surface and elastic properties of the iso-structural and iso-electronic LaSn 3 and YSn 3 intermetallic compounds are studied under pressure within the frame work of density functional theory including spin-orbit coupling. The LaSn 3 Fermi surface consists of two sheets, of which the second is very complex. Under pressure a third sheet appears around compression V/V 0 =0.94, while a small topology changes in the second sheet is seen at compression V/V 0 =0.90. This may be in accordance with the anomalous behavior in the superconducting transition temperature observed in LaSn 3 , which has been suggested to reflect a Fermi surface topological transition, along with a non-monotonic pressure dependence of the density of states at the Fermi level. The similar behavior is not observed in YSn 3 for which the Fermi surface includes three sheets already at ambient conditions, and the topology remains unchanged under pressure. The reason for the difference in behavior between LaSn 3 and YSn 3 is the role of spin-orbit coupling and the hybridization of La-4f state with the Sn-p state in the vicinity of the Fermi level, which is well explained using the band structure calculation. The elastic constants and related mechanical properties are calculated at ambient as well as at elevated pressures. The elastic constants increase with pressure for both compounds and satisfy the conditions for mechanical stability under pressure. (author)

  17. Reflection electron energy loss spectroscopy as efficient technique for the determination of optical properties of polystyrene intermixed with gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Deris, Jamileh [Department of Physics, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Hajati, Shaaker, E-mail: [Department of Physics, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of); Department of Semiconductors, Materials and Energy Research Center, Karaj 3177983634 (Iran, Islamic Republic of)


    Highlights: • Reflection Electron Energy Loss Spectroscopy of nano-metalized polymer. • Determination of real part of the dielectric function of nanostructured sample. • Determination of imaginary part of the dielectric function of nanostructured sample. • Determination of refractive index and coefficient of extinction of the sample. • Determination of reflection and absorption coefficients of nano-metalized Polymer. - Abstract: The electronic properties (electron inelastic cross section, energy loss function) of a nano-metalized polystyrene obtained by reflection electron energy loss spectroscopy (REELS) in a previous study [J. Deris, S. Hajati, S. Tougaard, V. Zaporojtchenko, Appl. Surf. Sci. 377 (2016) 44–47], which relies on the Yubero-Tougaard method, were used in the complementary application of Kramers-Kronig transformation to determine its optical properties such as the real part (ε{sub 1}) and imaginary part (ε{sub 2}) of the dielectric function (ε), refractive index (n), coefficients of extinction (k), reflection (R) and absorption (μ). The degree of intermixing of polystyrene thin film and gold nanoparticles of sizes 5.5 nm was controlled by annealing the sample to achieve a morphology in which the nanoparticles were homogeneously distributed within polystyrene. It is worth noting that no data are available on the optical properties of metalized polymers such as gold nanoparticles intermixed with polystyrene. Therefore, this work is of high importance in terms of both the sample studied here and the method applied. The advantage of the method applied here is that no information on the lateral distribution of the nanocomposite sample is required. This means that the REELS technique has been presented here to suitably, efficiently and easily obtain the optical properties of such nano-metalized polymer in which the metal nanoparticles have been vertically well distributed (homogeneous in depth). Therefore, for vertically homogeneous and

  18. Acrotelm pedogenesis of a Sphagnum bog is reflected in effective unsaturated hydraulic properties (United States)

    Weber, Tobias K. D.; Iden, Sascha C.; Durner, Wolfgang


    In ombrotrophic peatlands, the moisture content of the vadose zone (acrotelm) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Whether peatlands act as sinks or sources of atmospheric carbon thus relies on variably saturated flow processes. Modeling of these processes is crucial in assessing effects of changed environmental conditions on the future development of these ecosystems. The Richards equation (RE) is the standard model for water flow in soils, but it is not clear whether it can be applied to simulate water flow in live Sphagnum moss. To check the suitability of the RE to describe the water dynamics in drying moss and peat we conducted transient laboratory evaporation experiments on undisturbed samples from the entire acrotelm. The experimental data consisted of measured pressure heads in two depths and water fluxes, and were evaluated by inverse modelling using the RE as process model. The results showed that the measurements could be matched very well only if the soil hydraulic properties (SHPs) were represented by a suitable model. A successful parameterisation of the SHPs of the moss was based on pore-size distributions (PSD) which combine three distinct pore systems of the Sphagnum moss, reflecting an inter-, intra-, and inner-plant pore space. We had to extend the traditional van Genuchten-Mualem model to account for non-capillary water storage and flow to obtain consistent descriptions of the observations. For the deeper samples, the pedogenesis of the acrotelm, a process of compaction and biochemical degradation of the solid matrix, had considerably impact on the shape of the SHPs. The collapse of the inter-plant pores and their filling with smaller particles led gradually to bi-modal PSDs with increasing depth. This coincides with a homogenisation and a considerably reduction in horizontal variability of SHPs at greater depths. We conclude that the RE with adequate representation of SHPs is a valid process

  19. TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method. (United States)

    Wong, Yinting; Zhong, Dan; Song, Aotian; Hu, Yan


    This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 and a superhydrophobic agent were coated on the HGM surface in one step. TBT and PFOTES were selected as the Ti source and the superhydrophobic agent, respectively. They were both coated on the HGM, and after the hydrothermal process, the TBT turned to anatase TiO2. In this way, a PFOTES/TiO2-coated HGM (MCHGM) was prepared. For comparison, PFOTES single-coated HGM (F-SCHGM) and TiO2 single-coated HGM (Ti-SCHGM) were synthesized as well. The PFOTES and TiO2 coatings on the HGM surface were demonstrated through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive detector (EDS) characterizations. The MCHGM showed a higher contact angle (153°) but a lower sliding angle (16°) than F-SCHGM, with a contact angle of 141.2° and a sliding angle of 67°. In addition, both Ti-SCHGM and MCHGM displayed similar IR reflectivity values, which were about 5.8% higher than the original HGM and F-SCHGM. Also, the PFOTES coating barely changed the thermal conductivity. Therefore, F-SCHGM, with a thermal conductivity of 0.0479 W/(m·K), was quite like the original HGM, which was 0.0475 W/(m·K). MCHGM and Ti-SCHGM were also similar. Their thermal conductivity values were 0.0543 W/(m·K) and 0.0543 W/(m·K), respectively. The TiO2 coating slightly increased the thermal conductivity, but with the increase in reflectivity, the overall heat-insulation property was enhanced. Finally, since the IR-reflecting property is provided by the HGM coating, if the coating is fouled, the reflectivity decreases. Therefore, with the superhydrophobic coating, the surface is protected from fouling, and its lifetime is also prolonged.

  20. Classification of reflected signals from cavitated tooth surfaces using an artificial intelligence technique incorporating a fiber optic displacement sensor (United States)

    Rahman, Husna Abdul; Harun, Sulaiman Wadi; Arof, Hamzah; Irawati, Ninik; Musirin, Ismail; Ibrahim, Fatimah; Ahmad, Harith


    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.

  1. Study on the surface density of surface-active substances through total-reflection X-ray absorption fine structure measurement. (United States)

    Kashimoto, Kaoru; Takata, Youichi; Matsuda, Takashi; Ikeda, Norihiro; Matsubara, Hiroki; Takiue, Takanori; Aratono, Makoto; Tanida, Hajime; Watanabe, Iwao


    The total-reflection X-ray absorption fine structure (XAFS) method previously employed for the adsorption of dodecyltrimethylammonium bromide (DTAB) at the air/water interface was applied to that in the presence of NaBr. The surface concentration of the bromide ions Gamma(X)(B) of DTAB and NaBr was evaluated by using the Br K-edge absorption jump values of the total-reflection XAFS spectra and was compared to the corresponding value Gamma(H)(B) estimated from the dependence of surface tension on the bulk concentrations of DTAB m(1) and NaBr m(2). The Gamma(X)(B) values trace almost perfectly the Gamma(X)(B) versus m(1) curve up to a concentration near the critical micelle concentration (cmc) and deviate gradually above the concentration. This behavior is basically similar to that of the single DTAB system and ensures that the XAFS method is also applicable to the DTAB system, even in the presence of NaBr. In addition, this method was extended to the single nonionic amphiphile with covalently bonded bromine, and the surface concentrations of 6-bromo-1-hexanol (BrC6OH), Gamma(X)(1) and Gamma(H)(B), were evaluated and compared with each other. It was found that the Gamma(X)(1) value almost perfectly traces the Gamma(H)(1) versus m(1) curve, even at high surface concentrations. The excellent coincidence confirmed that the total-reflection XAFS method can be applied to the nonionic amphiphile system as well as a cationic surfactant with or without an added salt system. Finally, the difference between the Gamma(X)(B) and Gamma(H)(B) values observed in the DTAB with and without an added salt system is briefly described.

  2. Spectral reflectance characteristics of different snow and snow-covered land surface objects and mixed spectrum fitting (United States)

    Zhang, J.-H.; Zhou, Z.-M.; Wang, P.-J.; Yao, F.-M.; Yang, L.


    The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area. The result showed that for a pure snow spectrum, the snow reflectance peaks appeared from visible to 800 nm band locations; there was an obvious absorption valley of snow spectrum near 1030 nm wavelength. Compared with fresh snow, the reflection peaks of the old snow and melting snow showed different degrees of decline in the ranges of 300~1300, 1700~1800 and 2200~2300 nm, the lowest was from the compacted snow and frozen ice. For the vegetation and snow mixed spectral characteristics, it was indicated that the spectral reflectance increased for the snow-covered land types(including pine leaf with snow and pine leaf on snow background), due to the influence of snow background in the range of 350~1300 nm. However, the spectrum reflectance of mixed pixel remained a vegetation spectral characteristic. In the end, based on the spectrum analysis of snow, vegetation, and mixed snow/vegetation pixels, the mixed spectral fitting equations were established, and the results showed that there was good correlation between spectral curves by simulation fitting and observed ones(correlation coefficient R2=0.9509).

  3. Surface electromyography assessment of back muscle intrinsic properties. (United States)

    Larivière, Christian; Arsenault, A Bertrand; Gravel, Denis; Gagnon, Denis; Loisel, Patrick


    The purpose of this study was to assess (1) the reliability and (2) the sensitivity to low back pain status and gender of different EMG indices developed for the assessment of back muscle weakness, muscle fiber composition and fatigability. Healthy subjects (men and women) and chronic low back pain patients (men only) performed, in a static dynamometer, maximal and submaximal static trunk extension tasks (short and long duration) to assess weakness, fiber composition and fatigue. Surface EMG signals were recorded from four (bilateral) pairs of back muscles and three pairs of abdominal muscles. To assess reliability of the different EMG parameters, 40 male volunteers (20 controls and 20 chronic low back pain patients) were assessed on three occasions. Reliable EMG indices were achieved for both healthy and chronic low back pain subjects when specific measurement strategies were applied. The EMG parameters used to quantify weakness and fiber composition were insensitive to low back status and gender. The EMG fatigue parameters did not detect differences between genders but unexpectedly, healthy men showed higher fatigability than back pain patients. This result was attributed to the smaller absolute load that was attributed to the patients, a load that was defined relative to their maximal strength, a problematic measure with this population. An attempt was made to predict maximal back strength from anthropometric measurements but this prediction was prone to errors. The main difficulties and some potential solutions related to the assessment of back muscle intrinsic properties were discussed.

  4. Characterization, optical properties and laser ablation behavior of epoxy resin coatings reinforced with high reflectivity ceramic particles (United States)

    Li, Wenzhi; Kong, Jing; Wu, Taotao; Gao, Lihong; Ma, Zhuang; Liu, Yanbo; Wang, Fuchi; Wei, Chenghua; Wang, Lijun


    Thermal damage induced by high power energy, especially high power laser, significantly affects the lifetime and performance of equipment. High-reflectance coating/film has attracted considerable attention due to its good performance in the damage protection. Preparing a high-reflectance coating with high reaction endothermal enthalpy will effectively consume a large amount of incident energy and in turn protect the substrate from thermal damage. In this study, a low temperature process was used to prepare coatings onto substrate with complex shape and avoid thermal effect during molding. An advanced high reflection ceramic powder, La1‑xSrxTiO3+δ , was added in the epoxy adhesive matrix to improve the reflectivity of coating. The optical properties and laser ablation behaviors of coatings with different ceramic additive ratio of La1‑xSrxTiO3+δ and modified epoxy-La1‑xSrxTiO3+δ with ammonium polyphosphate coatings were investigated, respectively. We found that the reflectivity of coatings is extremely high due to mixed high-reflection La1‑xSrxTiO3+δ particles, up to 96% at 1070 nm, which can significantly improve the laser resistance. In addition, the ammonium polyphosphate modifies the residual carbon structure of epoxy resin from discontinuous fine particles structure to continuous and porous structure, which greatly enhances the thermal-insulation property of coating. Furthermore, the laser ablation threshold is improved obviously, which is from 800 W cm‑2 to 1000 W cm‑2.

  5. Tailoring Novel PTFE Surface Properties: Promoting Cell Adhesion and Antifouling Properties via a Wet Chemical Approach. (United States)

    Gabriel, Matthias; Niederer, Kerstin; Becker, Marc; Raynaud, Christophe Michel; Vahl, Christian-Friedrich; Frey, Holger


    Many biomaterials used for tissue engineering applications lack cell-adhesiveness and, in addition, are prone to nonspecific adsorption of proteins. This is especially important for blood-contacting devices such as vascular grafts and valves where appropriate surface properties should inhibit the initial attachment of platelets and promote endothelial cell colonization. As a consequence, the long-term outcome of the implants would be improved and the need for anticoagulation therapy could be reduced or even abolished. Polytetrafluoroethylene (PTFE), a frequently used polymer for various medical applications, was wet-chemically activated and subsequently modified by grafting the endothelial cell (EC) specific peptide arginine-glutamic acid-aspartic acid-valine (REDV) using a bifunctional polyethylene glycol (PEG)-spacer (known to reduce platelet and nonspecific protein adhesion). Modified and control surfaces were both evaluated in terms of EC adhesion, colonization, and the attachment of platelets. In addition, samples underwent bacterial challenges. The results strongly suggested that PEG-mediated peptide immobilization renders PTFE an excellent substrate for cellular growth while simultaneously endowing the material with antifouling properties.

  6. Detection of egg yolk antibodies reflecting Salmonella enteritidis infections using a surface plasmon resonance biosensor

    NARCIS (Netherlands)

    Thomas, M.E.; Bouma, A.; Eerden, van E.; Landman, W.J.M.; Knapen, van F.; Stegeman, J.A.; Bergwerff, A.A.


    A surface plasmon resonance (SPR) biosensor assay was developed on the basis of a lipopolysaccharide antigen of Salmonella enterica serovar enteritidis (S. enterica serovar enteritidis) to detect egg yolk antibodies against S. enterica serovar enteritidis. This biosensor assay was compared to two

  7. 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


    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

  8. 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


    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

  9. Neutron and X-ray reflection from surface monolayers of a lipopolyoxazoline

    DEFF Research Database (Denmark)

    Wurlitzer, A.; Politsch, E.; Cevc, G.


    were investigated as a function of surface pressure. The data are consistent with a fraction of the polyoxazoline moieties in brush-like conformations coexisting with a smaller fraction that is closely associated with the interface. Across the phase transition that is detected in the isotherm...

  10. The structure and properties of fluorite crystal surfaces


    Tasker, P.


    The surface energies, tensions and structure of the (111) and (110) surfaces of CaF2, SrF2, BaF2 and UO2, ThO2, PrO2, PuO2, CeO2 have been calculated using an ionic shell model. The surface energies for the natural cleavage plane (111) are compared with the available experimental data and agree well. The surface tensions indicate a compressive stress in both surfaces. The surface structures show increasing relaxation with increasing ion size and the rumpling of the (110) surface indicates a q...


    Directory of Open Access Journals (Sweden)

    V. P. Veiko


    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.

  12. Measurement of sugar content of watermelon using near-infrared reflectance spectroscopy in comparison with dielectric property (United States)

    Tao, Xuemei; Bao, Yidan


    The sugar content of watermelon is important to its taste thus influences the market. It's difficult to know whether the melon is sweet or not for consumers. We tried to develop a convenient meter to determine the sugar of watermelon. The first objective of this paper was to demonstrate the feasibility of using a near-infrared reflectance spectrometer (NIRS) to investigate the relationship between sugar content of watermelon and absorption spectra. The NIRS reflectance of nondestructive watermelon was measured with a Visible/NIR spectrophotometer in 325-1075nm range. The sugar content of watermelon was obtained with a handhold sugar content meter. The second objective was to measure the watermelon's dielectric property, such as dielectric resistance, capacitance, quality factor and dielectric loss. A digital electric bridge instrument was used to get the dielectric property. The experimental results show that they were related to watermelon's sugar content. A comparison between the two methods was made in the paper. The model derived from NIRS reflection is useful for class identification of Zaochun Hongyu watermelon though it's not quite accurate in sweetness prediction (the max. deviation is 0.7). Electric property bears little relation to sugar content of watermelon at this experiment and it couldn't be used as non-destructive inspection method.

  13. 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.


    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

  14. Enhancing light reflective properties on ITO glass by plasmonic effect of silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Dezhong Zhang

    Full Text Available The preparation of well-defined silver (Ag nanoparticle arrays is reported in this paper. Ag nanoparticles are electrodeposited on Indium tin oxide (ITO coated glass substrates at 30 °C. The size, shape and periodicity of the Ag nanoparticle arrays are well-controlled. We study the effect of particle size and interparticle distance on reflection enhancement. The sample at the deposition potential of −0.2 V for an electrodeposition time of 3600 s exhibits an enhancement of 28% in weighted reflection in contrast with bare ITO glass. This study reports the high reflection of Ag nanoparticle arrays by electrodeposition method might be application to large-scale photovoltaic devices.

  15. Frequency averaging of fluctuations in the cross-correlation reception of noiselike signals reflected from a rough sea surface (United States)

    Baranov, V. F.; Gerasimova, T. I.; Gulin, É. P.


    For noiselike signals reflected from a rough sea surface and received by a correlation receiver, the effect achieved at the receiver output as a result of frequency averaging of signal fluctuations is considered. Expressions characterizing the effect of frequency averaging are derived by using the generalized two-scale model describing the frequency correlation of strong fluctuations of the transfer function. Results of numerical calculations for the variance of fluctuations at the output of the correlation receiver are presented for different relative values of the frequency bandwidth of noiselike signals and the frequency correlation scales for the cases of both weak and strong fluctuations.

  16. Investigation of surface properties of physico-chemically modified natural fibres using inverse gas chromatography

    CSIR Research Space (South Africa)

    Cordeiro, N


    Full Text Available Inverse gas chromatography (IGC) is a suitable method to determine surface energy of natural fibres when compared to wetting techniques. In the present study, the surface properties of raw and modified lignocellulosic fibres have been investigated...

  17. Model of coordination melting of crystals and anisotropy of physical and chemical properties of the surface (United States)

    Bokarev, Valery P.; Krasnikov, Gennady Ya


    Based on the evaluation of the properties of crystals, such as surface energy and its anisotropy, the surface melting temperature, the anisotropy of the work function of the electron, and the anisotropy of adsorption, were shown the advantages of the model of coordination melting (MCM) in calculating the surface properties of crystals. The model of coordination melting makes it possible to calculate with an acceptable accuracy the specific surface energy of the crystals, the anisotropy of the surface energy, the habit of the natural crystals, the temperature of surface melting of the crystal, the anisotropy of the electron work function and the anisotropy of the adhesive properties of single-crystal surfaces. The advantage of our model is the simplicity of evaluating the surface properties of the crystal based on the data given in the reference literature. In this case, there is no need for a complex mathematical tool, which is used in calculations using quantum chemistry or modeling by molecular dynamics.

  18. 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.


    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.)

  19. On fatigue crack growth mechanisms of MMC: Reflection on analysis of 'multi surface initiations'

    International Nuclear Information System (INIS)

    Mkaddem, A.; El Mansori, M.


    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.

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

    Directory of Open Access Journals (Sweden)

    S. Zhang


    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.

  1. Proteome of conidial surface associated proteins of Aspergillus fumigatus reflecting potential vaccine candidates and allergens. (United States)

    Asif, Abdul R; Oellerich, Michael; Amstrong, Victor W; Riemenschneider, Birgit; Monod, Michel; Reichard, Utz


    Aspergillus fumigatus is a mold causing most of the invasive fungal lung infections in the immunocompromised host. In addition, the species is the causative agent of certain allergic diseases. Both in invasive and in allergic diseases, the conidial surface mediates the first contact with the human immune system. Thus, conidial surface proteins may be reasonable vaccine candidates as well as important allergens. To broaden the list of those antigens, intact viable Aspergillus conidia were extracted with mild alkaline buffer at pH 8.5 in the presence of a 1,3-beta-glucanase. The proteome of this fraction was separated by two- dimensional gel electrophoresis (2-DE) and analyzed by liquid chromatography coupled with tandem mass spectrometry. Altogether 26 different A. fumigatus proteins were identified, twelve of which contain a signal for secretion. Among these were the known major conidial surface protein rodlet A, one acid protease PEP2, one lipase, a putative disulfide isomerase and a putative fructose-1,6-biphosphatase. The known allergen Aspf 3 was identified among the proteins without a signal for secretion. On the basis of the recently annotated A. fumigatus genome (Nature 2005, 438, 1151-1156), proteome analysis is now a powerful tool to confirm expression of hypothetical proteins and, thereby to identify additional vaccine candidates and possible new allergens of this important fungal pathogen.

  2. Deriving surface soil moisture from reflected GNSS signal observations from a grassland site in southwestern France (United States)

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


    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.

  3. High-directional light source using photon recycling with a retro-reflective Dome incorporated with a textured LED die surface. (United States)

    Sun, Ching-Cherng; Chung, Shuang-Chao; Yang, Shuang-Hao; Yu, Yeh-Wei; Chien, Wei-Ting; Chen, Huang-Kuen; Chen, Shih-Peng


    This paper demonstrates a novel retro-reflective dome that enhances the directionality of a light emitting diode (LED) by recycling photons reflected by a textured LED die surface. A simulation model is developed to describe both the photon recycling process within the dome and the role of specific pyramid patterns on the top surface of the LED die. Advanced simulations showed that a perfectly polished surface with 100% reflectivity potentially enhances the directionality of the dome by 340%, 250%, and 240% using reflective domes with 10°, 20°, and 30° light cones, respectively. In the experiment, the directionality of the domes exhibiting surface imperfections is enhanced by approximately 160%, 150%, and 130% using 10°, 20°, and 30° light cones, respectively. By incorporating a textured top surface on the LED die, the proposed dome effectively increases the directionality of the LED light source.

  4. Determination of Mechanical and Surface Properties of Semicrystalline Polyhedral Oligomeric Silsesquioxane (POSS) Nanocomposites

    National Research Council Canada - National Science Library

    Moody, Laura E; Marchant, Darrell; Grabow, Wade W; Lee, Andre Y; Mabry, Joseph M


    INTRODUCTION: (1) Nanomodification of semicrystalline polymers -- unequalled thermal, mechanical and surface properties at low volume fractions that cannot be obtained using conventional fillers; (2...

  5. Determination of Mechanical and Surface Properties of Semicrystalline Polyhedral Oligomeric Silsequioxane (POSS) Nanocomposites

    National Research Council Canada - National Science Library

    Moody, Laura E; Marchant, Darrell; Grabow, Wade W; Lee, Andre Y; Mabry, Joseph M


    .... This study examines the ability of POSS to improve the mechanical and surface properties of three semicrystalline polymers, fluorinated ethylene-propylene (FEP), poly(vinylidene fluoride) (PVDF...

  6. Exploring Vesta's Surface Roughness and Dielectric Properties Using VIR Spectrometer and Bistatic Radar Observations by the Dawn Mission (United States)

    Palmer, E. M.; Heggy, E.; Capria, M. T.; Tosi, F.; Kofman, W. W.; Russell, C. T.


    Multiple lines of evidence from NASA's Dawn mission suggest transient volatile presence at the surface of asteroid Vesta. Radar remote sensing is a useful technique for the investigation of volatile content at the surface and shallow subsurface, but requires the use of accurate dielectric and topographic models in order to deconvolve the effect of surface roughness from the total observed radar backscatter. Toward this end, we construct a dielectric model for the dry, volatile-poor case of Vesta's surface to represent average surface conditions, and to assess the expected average range of dielectric properties due to known variations in mineralogy, temperature, and density as inferred from Dawn VIR data. We employ dielectric studies of lunar samples to serve as a suitable analog to the Vestan regolith, and in the case of 10-wavelength penetration depth of X-band frequency radar observations, our model yields ɛ' from 2.5 to 2.6 from the night to dayside of Vesta, and tan δ from 0.011 to 0.014. Our estimation of ɛ' corresponds to specular surface reflectivity of ~0.05. In addition to modeling, we have also conducted an opportunistic bistatic radar (BSR) experiment at Vesta using the communications antennas aboard Dawn and on Earth. In this configuration, Dawn transmits a continuous radar signal toward the Earth while orbiting Vesta. As the Dawn spacecraft passes behind Vesta (entering an occultation), the line of sight between Dawn and Earth intersects Vesta's surface, resulting in a reflection of radar waves from the surface and shallow subsurface, which are then received on Earth for analysis. The geometry of the Dawn BSR experiment results in high incidence angles on Vesta's surface, and leads to a differential Doppler shift of only a few 10s of Hz between the direct signal and the surface echo. As a consequence, this introduces ambiguity in the measurement of bandwidth and peak power of each surface echo. We report our interpretations of each surface echo in

  7. Geotechnical properties of surface sediments in the INDEX area

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    As a part of the environmental impact assessment studies, geotechnical properties of sediments were determined in the Central Indian Basin. The undrained shear strength and index properties of the siliceous sediments were determined on 20 box cores...

  8. Genomic signatures of paleodrainages in a freshwater fish along the southeastern coast of Brazil: genetic structure reflects past riverine properties. (United States)

    Thomaz, A T; Malabarba, L R; Knowles, L L


    Past shifts in connectivity in riverine environments (for example, sea-level changes) and the properties of current drainages can act as drivers of genetic structure and demographic processes in riverine population of fishes. However, it is unclear whether the same river properties that structure variation on recent timescales will also leave similar genomic signatures that reflect paleodrainage properties. By characterizing genetic structure in a freshwater fish species (Hollandichthys multifasciatus) from a system of basins along the Atlantic coast of Brazil we test for the effects of paleodrainages caused by sea-level changes during the Pleistocene. Given that the paleodrainage properties differ along the Brazilian coast, we also evaluate whether estimated genetic diversity within paleodrainages can be explained by past riverine properties (i.e., area and number of rivers in a paleodrainage). Our results demonstrate that genetic structure between populations is not just highly concordant with paleodrainages, but that differences in the genetic diversity among paleodrainages correspond to the joint effect of differences in the area encompassed by, and the number of rivers, within a paleodrainage. Our findings extend the influence of current riverine properties on genetic diversity to those associated with past paleodrainage properties. We discuss how these findings may explain the inconsistent support for paleodrainages in structuring divergence from different global regions and the importance of taking into account past conditions for understanding the high species diversity of freshwater fish that we currently observe in the world, and especially in the Neotropics.

  9. Variations within class-A β-lactamase physiochemical properties reflect evolutionary and environmental patterns, but not antibiotic specificity. (United States)

    Verma, Deeptak; Jacobs, Donald J; Livesay, Dennis R


    The bacterial enzyme β-lactamase hydrolyzes the β-lactam ring of penicillin and chemically related antibiotics, rendering them ineffective. Due to rampant antibiotic overuse, the enzyme is evolving new resistance activities at an alarming rate. Related, the enzyme's global physiochemical properties exhibit various amounts of conservation and variability across the family. To that end, we characterize the extent of property conservation within twelve different class-A β-lactamases, and conclusively establish that the systematic variations therein parallel their evolutionary history. Large and systematic differences within electrostatic potential maps and pairwise residue-to-residue couplings are observed across the protein, which robustly reflect phylogenetic outgroups. Other properties are more conserved (such as residue pKa values, electrostatic networks, and backbone flexibility), yet they also have systematic variations that parallel the phylogeny in a statistically significant way. Similarly, the above properties also parallel the environmental condition of the bacteria they are from in a statistically significant way. However, it is interesting and surprising that the only one of the global properties (protein charge) parallels the functional specificity patterns; meaning antibiotic resistance activities are not significantly constraining the global physiochemical properties. Rather, extended spectrum activities can emerge from the background of nearly any set of electrostatic and dynamic properties.

  10. Bone density does not reflect mechanical properties in early-stage arthrosis

    DEFF Research Database (Denmark)

    Ding, M.; Danielsen, C.C.; Hvid, I.


    : medial arthrosis, lateral control, normal medial and normal lateral controls. The specimens were tested in compression to determine mechanical properties and then physical/compositional properties. Compared to the normal medial control, we found reductions in ultimate stress, Young's modulus, and failure...

  11. Properties of weak contrast PP reflection/transmission coefficients for weakly anisotropic elastic media

    Czech Academy of Sciences Publication Activity Database

    Pšenčík, Ivan; Martins, J. L.


    Roč. 45, č. 2 (2001), s. 176-199 ISSN 0039-3169. [ICTCA'99. Trieste, 10.05.1999-14.05.1999] Institutional research plan: CEZ:AV0Z3012916 Keywords : elastic media * anisotropy * seismic reflection Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.680, year: 2001

  12. Wavelet Analysis of Soil Reflectance for the Characterization of Soil Properties (United States)

    Wavelet analysis has proven to be effective in many fields including signal processing and digital image analysis. Recently, it has been adapted to spectroscopy, where the reflectance of various materials is measured with respect to wavelength (nm) or wave number (cm-1). Spectra can cover broad wave...

  13. Reflected and diffuse ions backstreaming from the earth's bow shock 1. Basic properties

    International Nuclear Information System (INIS)

    Bonifazi, C.; Moreno, G.


    Plasma data supplied by the ISEE 2 solar wind experiment are used to perform the first extended statistical analysis of the basic moments of the ions backstream from the earth's bow shock. The analysis is based on 3253 ion spectra, corresponding to a total observation time of approx. =87 hours. It turns out that the density and total energy density of the backstream ions are, on the average, equal to approx. =1% and approx. =10% of those of the solar wind, respectively. The distinction between the 'reflected' and 'diffuse' populations has been confirmed and put on a quantitive basis using the ratio A = V /sub B/P/w/sub B/P between the bulk velocity and the rms thermal speed of the ions. The reflected ions are characterized by a bulk velocity V/sub B/P of the order of 2 times the solar wind velocity and by a temperature of approx.7 x 10 6 K. In contrast, the diffuse ions have, on the average, a bulk velocity 1.2 times the solar wind velocity and a temperature of 40 x 10 6 K. Therefore the total energy density of the diffuse ions is approx. =30% larger than that of the reflected ions. Finally, the kinetic and thermal energy densities are distributed quite differently in the two ion populations: in fact, approx. =70% of the total energy density is kinetic for the reflected ions, while this percentage decreases to approx. =20% for the diffuse ions

  14. Investigations of the Electronic Properties and Surface Structures of Aluminium-Rich Quasicrystalline Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, Jason A. [Iowa State Univ., Ames, IA (United States)


    equations. Transport behavior is described in terms of charge carriers and the mean-free time between carrier collisions. It is concluded that the mean-free time is much longer in the periodic direction than in the aperiodic direction. This difference produces the observed anisotropy in thermal transport. The third study presented a detailed analysis of the reversible, sputter-induced phase transformation which occurs on the 5-fold surface of an icosahedral Al-Cu-Fe quasicrystal. Reflection high-energy electron diffraction (RHEED), x-ray photoemission spectroscopy (XPS), and ultra-violet photoemission spectroscopy (UPS) data were collected as a function of annealing temperature and were used to probe surface structure, surface composition, and electronic structure, respectively. The composition and structure of the sputtered surface are consistent with a transformation to the β-Al-Cu-Fe cubic structure, and shows a sharp metallic cut-off in the spectral intensity of the electronic structure at the Fermi edge. Upon annealing the surface reverts to a quasicrystalline composition and structure. This transformation has been correlated with a reduction in the spectral intensity of the electronic structure at the Fermi level. This data clearly demonstrates that the observed reduction is intrinsic to a quasicrystalline surface. It is concluded that this is due to the opening of a pseudo-gap in the electronic density of states as the surface reverts from β-Al-Cu-Fe to quasicrystalline.

  15. Modeling the Acid-Base Properties of Montmorillonite Edge Surfaces. (United States)

    Tournassat, Christophe; Davis, James A; Chiaberge, Christophe; Grangeon, Sylvain; Bourg, Ian C


    The surface reactivity of clay minerals remains challenging to characterize because of a duality of adsorption surfaces and mechanisms that does not exist in the case of simple oxide surfaces: edge surfaces of clay minerals have a variable proton surface charge arising from hydroxyl functional groups, whereas basal surfaces have a permanent negative charge arising from isomorphic substitutions. Hence, the relationship between surface charge and surface potential on edge surfaces cannot be described using the Gouy-Chapman relation, because of a spillover of negative electrostatic potential from the basal surface onto the edge surface. While surface complexation models can be modified to account for these features, a predictive fit of experimental data was not possible until recently, because of uncertainty regarding the densities and intrinsic pK a values of edge functional groups. Here, we reexamine this problem in light of new knowledge on intrinsic pK a values obtained over the past decade using ab initio molecular dynamics simulations, and we propose a new formalism to describe edge functional groups. Our simulation results yield reasonable predictions of the best available experimental acid-base titration data.

  16. 1D Seismic reflection technique to increase depth information in surface seismic investigations (United States)

    Camilletti, Stefano; Fiera, Francesco; Umberto Pacini, Lando; Perini, Massimiliano; Prosperi, Andrea


    1D seismic methods, such as MASW Re.Mi. and HVSR, have been extensively used in engineering investigations, bedrock research, Vs profile and to some extent for hydrologic applications, during the past 20 years. Recent advances in equipment, sound sources and computer interpretation techniques, make 1D seismic methods highly effective in shallow subsoil modeling. Classical 1D seismic surveys allows economical collection of subsurface data however they fail to return accurate information for depths greater than 50 meters. Using a particular acquisition technique it is possible to collect data that can be quickly processed through reflection technique in order to obtain more accurate velocity information in depth. Furthermore, data processing returns a narrow stratigraphic section, alongside the 1D velocity model, where lithological boundaries are represented. This work will show how collect a single-CMP to determine: (1) depth of bedrock; (2) gravel layers in clayey domains; (3) accurate Vs profile. Seismic traces was processed by means a new software developed in collaboration with SARA electronics instruments S.r.l company, Perugia - ITALY. This software has the great advantage of being able to be used directly in the field in order to reduce the times elapsing between acquisition and processing.

  17. Detection of aflatoxin and surface mould contaminated figs by using Fourier transform near-infrared reflectance spectroscopy. (United States)

    Durmuş, Efkan; Güneş, Ali; Kalkan, Habil


    Aflatoxins are toxic metabolites that are mainly produced by members of the Aspergillus section Flavi on many agricultural products. Certain agricultural products such as figs are known to be high risk products for aflatoxin contamination. Aflatoxin contaminated figs may show a bright greenish yellow fluorescence (BGYF) under ultraviolet (UV) light at a wavelength of 365 nm. Traditionally, BGYF positive figs are manually selected by workers. However, manual selection depends on the expertise level of the workers and it may cause them skin-related health problems due to UV radiation. In this study, we propose a non-invasive approach to detect aflatoxin and surface mould contaminated figs by using Fourier transform near-infrared (FT-NIR) reflectance spectroscopy. A classification accuracy of 100% is achieved for classifying the figs into aflatoxin contaminated/uncontaminated and surface mould contaminated/uncontaminated categories. In addition, a strong correlation has been found between aflatoxin and surface mould. Combined with pattern classification methods, the NIR spectroscopy can be used to detect aflatoxin contaminated figs non-invasively. Furthermore, a positive correlation between surface mould and aflatoxin contamination leads to a promising alternative indicator for the detection of aflatoxin-contaminated figs. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  18. Properties that influence the specific surface areas of carbon nanotubes and nanofibers. (United States)

    Birch, M Eileen; Ruda-Eberenz, Toni A; Chai, Ming; Andrews, Ronnee; Hatfield, Randal L


    Commercially available carbon nanotubes and nanofibers were analyzed to examine possible relationships between their Brunauer-Emmett-Teller specific surface areas (SSAs) and their physical and chemical properties. Propertie