Greg Smestad, Leonardo Micheli, Thomas Germer, and Eduardo Fernández presented research on characterizing the optical effects of soiling on PV glass and modules. They measured the transmission of glass coupons exposed outdoors at multiple locations over 8 weeks and found soiling reduced transmission more at shorter wavelengths. Particle area coverage on the coupons correlated linearly with reduced hemispherical transmittance. Angular measurements showed soiling impacts transmission more for direct light than hemispherical. The research aims to better understand how soiling impacts PV performance globally.
This document provides supporting information for a research article on silicon nanowire solar cells. It describes the materials and methods used, including:
1) The synthesis of silicon nanowire cores and shells of different doping types using a home-built reactor.
2) Fabrication of nanowire devices, including contact deposition and measurements of current-voltage characteristics and quantum efficiency.
3) Finite-difference time-domain simulations of light absorption in nanowires compared to bulk silicon.
1. The document describes measuring and analyzing the radiation patterns of a dual-polarized meteorological radar antenna that was upgraded from single to dual polarization.
2. A Fresnel-zone holographic technique was used to measure the antenna's co-polarized and cross-polarized radiation patterns. The sidelobes were found to be higher than predicted.
3. Analysis of the aperture field data identified surface errors in the reflector dish and shadowing from the feed crook as contributing to the elevated sidelobes. Both theoretical modeling and manipulation of the measured data supported this finding.
The document describes a new algorithm for correcting the bidirectional reflectance distribution function (BRDF) of remote sensing reflectance measurements in coastal waters. Through radiative transfer simulations for a wide range of conditions, the authors developed a model relating remote sensing reflectance to the inherent optical properties of coastal waters. The new BRDF correction algorithm was shown to reduce uncertainty to below 1% when applied to both in situ and satellite ocean color data, improving on an existing open ocean algorithm. Its application significantly improved the match between in situ and MODIS satellite measurements of coastal waters.
The document discusses the challenge of characterizing particulate matter using remote sensing data due to the complex and multidimensional nature of aerosols. It presents results from using SeaWiFS satellite data combined with surface observations to characterize aerosols over the US from 2000-2003. Specific cases studied include quantifying smoke emissions from agricultural fires in Kansas in 2003 by analyzing the optical thickness and shape of smoke plumes. Summer climatologies of aerosol optical thickness over the US from 2000-2004 are also shown.
This document discusses a study on the influence of artificial soiling on the power losses of different photovoltaic (PV) technologies. Four types of artificial soiling (salt, sand, fine dust, coarse dust) were deposited on glass samples at different inclinations. The direct and hemispherical transmittance of the soiled samples was measured. Power losses were then calculated for concentrating photovoltaics and crystalline silicon, cadmium telluride, and copper indium gallium selenide PV technologies. Measurements on crystalline silicon solar cells validated that the calculations accurately predicted the power losses. The study found that power losses were always higher for concentrating PV compared to other technologies for the same soiling conditions.
http://www.surfacetreatments.it/thinfilms
Commissioning of the JLab Surface Impedance Characterization (SIC) System (Charles Reece - 20')
Speaker: Charles Reece - Jefferson Lab, Newport News (VA) USA | Duration: 20 min.
Abstract
Binping Xiao, Larry Phillips, and Charles Reece
A system for making direct calorimetric measurements of the surface resistance at 7.5 GHz of small samples of variously prepared superconducting surfaces has been commissioned at JLab. The flat, 50 mm diameter sample temperature is regulated independently of the balance of the TE011 sapphire-loaded cavity, enabling Rs and Δλ measurements from 2 K to Tc of the sample. Initial operation, limited by available rf power, has extended to Bpk of 18 mT. The calorimeter resolution is better than 10 nΩ, and the sampled surface area is ~ 0.8 cm2. The SIC has been commissioned with a bulk Nb sample, demonstrating excellent agreement with standard BCS characterizations. Initial application to SRF thin films has begun. We are eager to apply it to non-niobium materials. Preparations for a second generation with extended dynamic range have already begun.
The document discusses radiometric corrections for remote sensing images. It describes how digital numbers are converted to top-of-atmosphere reflectance values using calibration coefficients and solar irradiance normalization. Atmospheric corrections are needed to estimate top-of-canopy reflectance and account for effects of gas absorption, scattering, and emission using a radiative transfer model like 6S. Parameters for the 6S model include viewing geometry, atmospheric properties, and spectral filter functions. Aerosol optical thickness can be obtained from Aeronet ground stations. Radiometric calibration is needed using reference reflectance panels.
The document discusses image distortion effects in subsurface synthetic aperture radar (SAR) imaging of deserts and proposes an iterative corrective approach. It summarizes that subsurface SAR can map subsurface topography under sand but images are distorted due to geometric distortion and defocusing. It then proposes using dual-frequency SAR, with VHF penetrating sand and Ka imaging the surface, along with an iterative algorithm using the surface data to correct the VHF image and retrieve accurate subsurface heights. Simulation results showed the approach improved height resolution and coherence by 20-40% compared to conventional SAR.
This document provides supporting information for a research article on silicon nanowire solar cells. It describes the materials and methods used, including:
1) The synthesis of silicon nanowire cores and shells of different doping types using a home-built reactor.
2) Fabrication of nanowire devices, including contact deposition and measurements of current-voltage characteristics and quantum efficiency.
3) Finite-difference time-domain simulations of light absorption in nanowires compared to bulk silicon.
1. The document describes measuring and analyzing the radiation patterns of a dual-polarized meteorological radar antenna that was upgraded from single to dual polarization.
2. A Fresnel-zone holographic technique was used to measure the antenna's co-polarized and cross-polarized radiation patterns. The sidelobes were found to be higher than predicted.
3. Analysis of the aperture field data identified surface errors in the reflector dish and shadowing from the feed crook as contributing to the elevated sidelobes. Both theoretical modeling and manipulation of the measured data supported this finding.
The document describes a new algorithm for correcting the bidirectional reflectance distribution function (BRDF) of remote sensing reflectance measurements in coastal waters. Through radiative transfer simulations for a wide range of conditions, the authors developed a model relating remote sensing reflectance to the inherent optical properties of coastal waters. The new BRDF correction algorithm was shown to reduce uncertainty to below 1% when applied to both in situ and satellite ocean color data, improving on an existing open ocean algorithm. Its application significantly improved the match between in situ and MODIS satellite measurements of coastal waters.
The document discusses the challenge of characterizing particulate matter using remote sensing data due to the complex and multidimensional nature of aerosols. It presents results from using SeaWiFS satellite data combined with surface observations to characterize aerosols over the US from 2000-2003. Specific cases studied include quantifying smoke emissions from agricultural fires in Kansas in 2003 by analyzing the optical thickness and shape of smoke plumes. Summer climatologies of aerosol optical thickness over the US from 2000-2004 are also shown.
This document discusses a study on the influence of artificial soiling on the power losses of different photovoltaic (PV) technologies. Four types of artificial soiling (salt, sand, fine dust, coarse dust) were deposited on glass samples at different inclinations. The direct and hemispherical transmittance of the soiled samples was measured. Power losses were then calculated for concentrating photovoltaics and crystalline silicon, cadmium telluride, and copper indium gallium selenide PV technologies. Measurements on crystalline silicon solar cells validated that the calculations accurately predicted the power losses. The study found that power losses were always higher for concentrating PV compared to other technologies for the same soiling conditions.
http://www.surfacetreatments.it/thinfilms
Commissioning of the JLab Surface Impedance Characterization (SIC) System (Charles Reece - 20')
Speaker: Charles Reece - Jefferson Lab, Newport News (VA) USA | Duration: 20 min.
Abstract
Binping Xiao, Larry Phillips, and Charles Reece
A system for making direct calorimetric measurements of the surface resistance at 7.5 GHz of small samples of variously prepared superconducting surfaces has been commissioned at JLab. The flat, 50 mm diameter sample temperature is regulated independently of the balance of the TE011 sapphire-loaded cavity, enabling Rs and Δλ measurements from 2 K to Tc of the sample. Initial operation, limited by available rf power, has extended to Bpk of 18 mT. The calorimeter resolution is better than 10 nΩ, and the sampled surface area is ~ 0.8 cm2. The SIC has been commissioned with a bulk Nb sample, demonstrating excellent agreement with standard BCS characterizations. Initial application to SRF thin films has begun. We are eager to apply it to non-niobium materials. Preparations for a second generation with extended dynamic range have already begun.
The document discusses radiometric corrections for remote sensing images. It describes how digital numbers are converted to top-of-atmosphere reflectance values using calibration coefficients and solar irradiance normalization. Atmospheric corrections are needed to estimate top-of-canopy reflectance and account for effects of gas absorption, scattering, and emission using a radiative transfer model like 6S. Parameters for the 6S model include viewing geometry, atmospheric properties, and spectral filter functions. Aerosol optical thickness can be obtained from Aeronet ground stations. Radiometric calibration is needed using reference reflectance panels.
The document discusses image distortion effects in subsurface synthetic aperture radar (SAR) imaging of deserts and proposes an iterative corrective approach. It summarizes that subsurface SAR can map subsurface topography under sand but images are distorted due to geometric distortion and defocusing. It then proposes using dual-frequency SAR, with VHF penetrating sand and Ka imaging the surface, along with an iterative algorithm using the surface data to correct the VHF image and retrieve accurate subsurface heights. Simulation results showed the approach improved height resolution and coherence by 20-40% compared to conventional SAR.
Explanation of very simple methods for atmospheric corrections and an example adapted from a paper of the Dept. of Thermodynamics, University of Valencia, Spain.
The document presents a method to retrieve properties of biomass burning aerosols using a combination of near-UV radiance measurements from the GOSAT/CAI sensor and near-IR polarimetry measurements from the PARASOL/POLDER sensor. The method involves estimating ground reflectance, atmospheric light, aerosol models using refractive indices, vertical aerosol profiles from CALIPSO data, and retrieving aerosol optical thickness, Angstrom exponent and single scattering albedo. Validation with AERONET data shows the retrieved aerosol optical thickness and Angstrom exponent values match partially. The method demonstrates the biomass burning aerosol properties vary over plumes with optical depth and Angstrom exponent
1) The document discusses using silver nanoparticles to enhance Raman scattering signals through surface enhanced Raman spectroscopy (SERS) for studying heat transport in quantum dots.
2) Different methods for synthesizing silver nanoparticles were explored and nanoparticles were used to significantly enhance, by at least a factor of 90, the Raman signal of a test molecule (crystal violet).
3) For future work, the researchers want to use the silver nanoparticles to enhance Raman scattering from quantum dots to study heat transport in these nanomaterials.
This document summarizes a new approach for classifying remote sensing signatures extracted from multispectral imagery. It combines spectral signatures to perform accurate classification. Simulation results are provided to verify the efficiency of the proposed weighted pixel statistics approach, which uses information from multiple spectral bands. It is shown to provide more accurate and less smoothed identification of classes compared to traditional weighted order statistics methods.
This document discusses the potential for x-ray interferometry and the Maxim Pathfinder mission concept. It describes how an x-ray interferometer could achieve much higher resolution than current x-ray telescopes by using multiple collector spacecraft separated by long distances. The Maxim Pathfinder would demonstrate 100 microarcsecond resolution using two spacecraft separated by 450 km. System modeling tools would be crucial for development and optimization of the interferometer design.
This study investigates the scale effect of the relationship between the normalized difference vegetation index (NDVI) and land surface temperature (T) and improves a thermal sharpening method called TsHARP. The study finds that the slope of the NDVI-T relationship increases more significantly with spatial extent than with spatial resolution alone. An improved TsHARP method is developed that establishes the NDVI-T regression relationship based on the spatial extent of individual thermal pixels, rather than the entire image extent. Testing shows the improved method produces a sharper and more accurate thermal sharpening result compared to the original TsHARP method.
This document discusses a project to use Medipix detectors to measure ambient radiation levels in the CMS cavern at CERN. Fourteen Medipix3RX detectors will be installed at seven locations to measure particle fluxes and residual radiation doses. The Medipix detectors will be read out using MARSTM electronics. Simulations using FLUKA were performed to predict radiation levels and optimize detector design. Detectors containing lithium fluoride or polyethylene conversion layers will be installed next year to distinguish neutron-induced signals from background radiation.
1) P-band SAR tomography can provide 3D images of tropical forests with resolution along the vertical direction, exploiting the relationship between reflectivity and multi-baseline signals.
2) Analysis of SAR tomography data from French Guiana showed scattering mechanisms are linked to the ground level and canopy level, with HV polarization dominating volume scattering at the canopy.
3) Relating scattering to independently measured biomass at two sites showed significant correlation between biomass and backscattering from layers between 20-40m above the ground, indicating sensitivity to total above-ground biomass.
The document describes different methodologies used by various teams to measure the spectral reflectance of the Tuz Gölü site in Turkey for satellite calibration validation purposes. It discusses the principles of field reflectance measurement, instrumentation used including spectroradiometers and reference panels, and different spatial sampling strategies employed, such as spaced point sampling averaging multiple measurements, sampling with local variability assessment, and in-motion continuous sampling. Preliminary results showed good agreement between teams for a smaller area but less consistency for a larger area likely due to differences in spatial and temporal sampling.
The document describes an x-ray scattering study of capillary condensation in mesoporous silica. The researchers developed a new wide-angle x-ray scattering (WAXS) method to measure the Poisson's ratio and Young's modulus of nanoporous materials using capillary condensation. They used x-ray scattering techniques and gas sorption analysis to determine strains and stresses in mesoporous silica samples from capillary forces during condensation. Comparing slopes from small-angle and wide-angle x-ray data, they calculated the Poisson's ratio and elastic modulus of the samples, finding annealing increased the strength of one sample significantly.
This study evaluated the use of multispectral and hyperspectral sensor data to estimate crop residue cover over agricultural areas. Hyperspectral data provided more accurate residue cover estimates than multispectral data due to greater spectral sensitivity. Models using a cellulose absorption index performed best. Residue cover estimates from hyperspectral data were substituted into models developed using multispectral data, improving accuracy of estimates from broader coverage sensors. Future work will focus on sensor fusion methods and integrating residue cover information into hydrologic models.
This document discusses several approaches for atmospheric correction of remote sensing imagery:
1) Image-based methods like the dark pixel method and regression method estimate and remove atmospheric path radiance.
2) The empirical line method uses ground targets of known reflectance to model atmospheric effects.
3) Radiative transfer models precisely account for atmospheric conditions using numerical models like MODTRAN or 6S to convert pixel values to surface reflectance.
4) Relative correction methods normalize images without absolute calibration to surface reflectance. Atmospheric correction is needed to accurately analyze surface properties from remote sensing data and compare images acquired at different times or wavelengths.
Synthesis, Electrical and Optical Properties of Nickel Sulphate Hexa Hydrate ...IJERA Editor
This document summarizes the synthesis and characterization of nickel sulfate hexa hydrate (NSH) single crystals doped with L-arginine. NSH crystals were grown using the slow evaporation technique with L-arginine doping concentrations from 0.2 to 1 mole%. The grown crystals were characterized through X-ray diffraction, dielectric, and optical studies. XRD analysis confirmed the crystalline structure of the doped crystals. Dielectric measurements showed an increase in dielectric constants and conductivity with increasing temperature. UV-visible spectroscopy revealed that doping altered the band gap of pure NSH crystals. The study suggests doped crystals could have applications in microelectronics due to their low dielectric properties.
1) Raman spectroscopy was used to study the thermal maturity of solid bitumen from a sample with low maturity (0.61% reflectance). However, initial measurements showed intense fluorescence that obscured the typical Raman bands.
2) Repeated measurements at the same location caused the fluorescence background to decrease over time, revealing the Raman bands more clearly without artificially altering the sample.
3) Multiple measurements allowed the fluorescent component to be isolated from the Raman spectrum, producing a clean spectrum free of background interference. This method provides a way to apply Raman spectroscopy to samples that normally exhibit strong fluorescence.
Atmospheric Correction of Remotely Sensed Images in Spatial and Transform DomainCSCJournals
Remotely sensed data is an effective source of information for monitoring changes in land use and land cover. However remotely sensed images are often degraded due to atmospheric effects or physical limitations. Atmospheric correction minimizes or removes the atmospheric influences that are added to the pure signal of target and to extract more accurate information. The atmospheric correction is often considered critical pre-processing step to achieve full spectral information from every pixel especially with hyperspectral and multispectral data. In this paper, multispectral atmospheric correction approaches that require no ancillary data are presented in spatial domain and transform domain. We propose atmospheric correction using linear regression model based on the wavelet transform and Fourier transform. They are tested on Landsat image consisting of 7 multispectral bands and their performance is evaluated using visual and statistical measures. The application of the atmospheric correction methods for vegetation analyses using Normalized Difference Vegetation Index is also presented in this paper.
This document summarizes a study that investigated whether the spectral reflectance of common plant species is affected by exposure to volatile organic compounds (VOCs). Researchers from Infoterra Ltd and the Centre for Ecology and Hydrology conducted a field experiment with six open-top chambers, three with VOC treatment and three controls. Over 1000 leaf specimens from different plant species were measured twice during the growing season. The mean reflectance of leaves from treated and control dock plants was found to be very similar across all wavelengths, indicating no significant effect of the VOC mixture on spectral reflectance. The document also describes the Network for Calibration and Validation of Earth Observation data, a knowledge transfer network aimed at disseminating best practices for calibration and validation of
Exploring Sources of Uncertainties in Solar Resource Measurements
The presentation explored various sources of uncertainty in solar resource measurements, including calibration differences, spectral mismatch, and soiling effects. Calibration differences between manufacturers and outdoor methods provided irradiance differences up to 2% for pyranometers and 1% for pyrheliometers. Spectral mismatch contributed to spectral errors up to 1.6% and soiling reduced instrument output by 0.2-27% due to decreased transmittance. Quantifying uncertainty from multiple sources is essential for accurate solar resource assessment and project performance.
MODELING STUDY OF LASER BEAM SCATTERING BY DEFECTS ON SEMICONDUCTOR WAFERSjmicro
Accurate modeling of light scattering from nanometer scale defects on Silicon wafersiscritical for enabling
increasingly shrinking semiconductor technology nodes of the future. Yet, such modeling of defect
scattering remains unsolved since existing modeling techniques fail to account for complex defect and
wafer geometries. Here, we present results of laser beam scattering from spherical and ellipsoidal
particles located on the surface of a silicon wafer. A commercially available electromagnetic field solver
(HFSS) was deployed on a multiprocessor cluster to obtain results with previously unknown accuracy
down to light scattering intensity of -170 dB. We compute three dimensional scattering patterns of silicon
nanospheres located on a semiconductor wafer for both perpendicular and parallel polarization and show
the effect of sphere size on scattering. We further computer scattering patterns of nanometer scale
ellipsoidal particles having different orientation angles and unveil the effects of ellipsoidal orientation on
scattering.
MODELING STUDY OF LASER BEAM SCATTERING BY DEFECTS ON SEMICONDUCTOR WAFERSjmicro
Accurate modeling of light scattering from nanometer scale defects on Silicon wafersiscritical for enabling
increasingly shrinking semiconductor technology nodes of the future. Yet, such modeling of defect
scattering remains unsolved since existing modeling techniques fail to account for complex defect and
wafer geometries. Here, we present results of laser beam scattering from spherical and ellipsoidal
particles located on the surface of a silicon wafer. A commercially available electromagnetic field solver
(HFSS) was deployed on a multiprocessor cluster to obtain results with previously unknown accuracy
down to light scattering intensity of -170 dB. We compute three dimensional scattering patterns of silicon
nanospheres located on a semiconductor wafer for both perpendicular and parallel polarization and show
the effect of sphere size on scattering. We further computer scattering patterns of nanometer scale
ellipsoidal particles having different orientation angles and unveil the effects of ellipsoidal orientation on
scattering.
This document discusses microfabrication processes used to manufacture microelectromechanical systems (MEMS) and microsystems. It describes that traditional machine tools cannot be used at the microscale, so physical-chemical processes developed for integrated circuits are adopted. Key microfabrication processes discussed include photolithography, ion implantation, diffusion, oxidation, deposition, and etching. Photolithography involves using a photosensitive film and optical image to produce patterns on a substrate. Ion implantation and diffusion are methods for doping silicon substrates with dopants like boron and phosphorus. Fick's laws of diffusion and the diffusion equation are provided to analyze dopant distribution over time.
Explanation of very simple methods for atmospheric corrections and an example adapted from a paper of the Dept. of Thermodynamics, University of Valencia, Spain.
The document presents a method to retrieve properties of biomass burning aerosols using a combination of near-UV radiance measurements from the GOSAT/CAI sensor and near-IR polarimetry measurements from the PARASOL/POLDER sensor. The method involves estimating ground reflectance, atmospheric light, aerosol models using refractive indices, vertical aerosol profiles from CALIPSO data, and retrieving aerosol optical thickness, Angstrom exponent and single scattering albedo. Validation with AERONET data shows the retrieved aerosol optical thickness and Angstrom exponent values match partially. The method demonstrates the biomass burning aerosol properties vary over plumes with optical depth and Angstrom exponent
1) The document discusses using silver nanoparticles to enhance Raman scattering signals through surface enhanced Raman spectroscopy (SERS) for studying heat transport in quantum dots.
2) Different methods for synthesizing silver nanoparticles were explored and nanoparticles were used to significantly enhance, by at least a factor of 90, the Raman signal of a test molecule (crystal violet).
3) For future work, the researchers want to use the silver nanoparticles to enhance Raman scattering from quantum dots to study heat transport in these nanomaterials.
This document summarizes a new approach for classifying remote sensing signatures extracted from multispectral imagery. It combines spectral signatures to perform accurate classification. Simulation results are provided to verify the efficiency of the proposed weighted pixel statistics approach, which uses information from multiple spectral bands. It is shown to provide more accurate and less smoothed identification of classes compared to traditional weighted order statistics methods.
This document discusses the potential for x-ray interferometry and the Maxim Pathfinder mission concept. It describes how an x-ray interferometer could achieve much higher resolution than current x-ray telescopes by using multiple collector spacecraft separated by long distances. The Maxim Pathfinder would demonstrate 100 microarcsecond resolution using two spacecraft separated by 450 km. System modeling tools would be crucial for development and optimization of the interferometer design.
This study investigates the scale effect of the relationship between the normalized difference vegetation index (NDVI) and land surface temperature (T) and improves a thermal sharpening method called TsHARP. The study finds that the slope of the NDVI-T relationship increases more significantly with spatial extent than with spatial resolution alone. An improved TsHARP method is developed that establishes the NDVI-T regression relationship based on the spatial extent of individual thermal pixels, rather than the entire image extent. Testing shows the improved method produces a sharper and more accurate thermal sharpening result compared to the original TsHARP method.
This document discusses a project to use Medipix detectors to measure ambient radiation levels in the CMS cavern at CERN. Fourteen Medipix3RX detectors will be installed at seven locations to measure particle fluxes and residual radiation doses. The Medipix detectors will be read out using MARSTM electronics. Simulations using FLUKA were performed to predict radiation levels and optimize detector design. Detectors containing lithium fluoride or polyethylene conversion layers will be installed next year to distinguish neutron-induced signals from background radiation.
1) P-band SAR tomography can provide 3D images of tropical forests with resolution along the vertical direction, exploiting the relationship between reflectivity and multi-baseline signals.
2) Analysis of SAR tomography data from French Guiana showed scattering mechanisms are linked to the ground level and canopy level, with HV polarization dominating volume scattering at the canopy.
3) Relating scattering to independently measured biomass at two sites showed significant correlation between biomass and backscattering from layers between 20-40m above the ground, indicating sensitivity to total above-ground biomass.
The document describes different methodologies used by various teams to measure the spectral reflectance of the Tuz Gölü site in Turkey for satellite calibration validation purposes. It discusses the principles of field reflectance measurement, instrumentation used including spectroradiometers and reference panels, and different spatial sampling strategies employed, such as spaced point sampling averaging multiple measurements, sampling with local variability assessment, and in-motion continuous sampling. Preliminary results showed good agreement between teams for a smaller area but less consistency for a larger area likely due to differences in spatial and temporal sampling.
The document describes an x-ray scattering study of capillary condensation in mesoporous silica. The researchers developed a new wide-angle x-ray scattering (WAXS) method to measure the Poisson's ratio and Young's modulus of nanoporous materials using capillary condensation. They used x-ray scattering techniques and gas sorption analysis to determine strains and stresses in mesoporous silica samples from capillary forces during condensation. Comparing slopes from small-angle and wide-angle x-ray data, they calculated the Poisson's ratio and elastic modulus of the samples, finding annealing increased the strength of one sample significantly.
This study evaluated the use of multispectral and hyperspectral sensor data to estimate crop residue cover over agricultural areas. Hyperspectral data provided more accurate residue cover estimates than multispectral data due to greater spectral sensitivity. Models using a cellulose absorption index performed best. Residue cover estimates from hyperspectral data were substituted into models developed using multispectral data, improving accuracy of estimates from broader coverage sensors. Future work will focus on sensor fusion methods and integrating residue cover information into hydrologic models.
This document discusses several approaches for atmospheric correction of remote sensing imagery:
1) Image-based methods like the dark pixel method and regression method estimate and remove atmospheric path radiance.
2) The empirical line method uses ground targets of known reflectance to model atmospheric effects.
3) Radiative transfer models precisely account for atmospheric conditions using numerical models like MODTRAN or 6S to convert pixel values to surface reflectance.
4) Relative correction methods normalize images without absolute calibration to surface reflectance. Atmospheric correction is needed to accurately analyze surface properties from remote sensing data and compare images acquired at different times or wavelengths.
Synthesis, Electrical and Optical Properties of Nickel Sulphate Hexa Hydrate ...IJERA Editor
This document summarizes the synthesis and characterization of nickel sulfate hexa hydrate (NSH) single crystals doped with L-arginine. NSH crystals were grown using the slow evaporation technique with L-arginine doping concentrations from 0.2 to 1 mole%. The grown crystals were characterized through X-ray diffraction, dielectric, and optical studies. XRD analysis confirmed the crystalline structure of the doped crystals. Dielectric measurements showed an increase in dielectric constants and conductivity with increasing temperature. UV-visible spectroscopy revealed that doping altered the band gap of pure NSH crystals. The study suggests doped crystals could have applications in microelectronics due to their low dielectric properties.
1) Raman spectroscopy was used to study the thermal maturity of solid bitumen from a sample with low maturity (0.61% reflectance). However, initial measurements showed intense fluorescence that obscured the typical Raman bands.
2) Repeated measurements at the same location caused the fluorescence background to decrease over time, revealing the Raman bands more clearly without artificially altering the sample.
3) Multiple measurements allowed the fluorescent component to be isolated from the Raman spectrum, producing a clean spectrum free of background interference. This method provides a way to apply Raman spectroscopy to samples that normally exhibit strong fluorescence.
Atmospheric Correction of Remotely Sensed Images in Spatial and Transform DomainCSCJournals
Remotely sensed data is an effective source of information for monitoring changes in land use and land cover. However remotely sensed images are often degraded due to atmospheric effects or physical limitations. Atmospheric correction minimizes or removes the atmospheric influences that are added to the pure signal of target and to extract more accurate information. The atmospheric correction is often considered critical pre-processing step to achieve full spectral information from every pixel especially with hyperspectral and multispectral data. In this paper, multispectral atmospheric correction approaches that require no ancillary data are presented in spatial domain and transform domain. We propose atmospheric correction using linear regression model based on the wavelet transform and Fourier transform. They are tested on Landsat image consisting of 7 multispectral bands and their performance is evaluated using visual and statistical measures. The application of the atmospheric correction methods for vegetation analyses using Normalized Difference Vegetation Index is also presented in this paper.
This document summarizes a study that investigated whether the spectral reflectance of common plant species is affected by exposure to volatile organic compounds (VOCs). Researchers from Infoterra Ltd and the Centre for Ecology and Hydrology conducted a field experiment with six open-top chambers, three with VOC treatment and three controls. Over 1000 leaf specimens from different plant species were measured twice during the growing season. The mean reflectance of leaves from treated and control dock plants was found to be very similar across all wavelengths, indicating no significant effect of the VOC mixture on spectral reflectance. The document also describes the Network for Calibration and Validation of Earth Observation data, a knowledge transfer network aimed at disseminating best practices for calibration and validation of
Exploring Sources of Uncertainties in Solar Resource Measurements
The presentation explored various sources of uncertainty in solar resource measurements, including calibration differences, spectral mismatch, and soiling effects. Calibration differences between manufacturers and outdoor methods provided irradiance differences up to 2% for pyranometers and 1% for pyrheliometers. Spectral mismatch contributed to spectral errors up to 1.6% and soiling reduced instrument output by 0.2-27% due to decreased transmittance. Quantifying uncertainty from multiple sources is essential for accurate solar resource assessment and project performance.
MODELING STUDY OF LASER BEAM SCATTERING BY DEFECTS ON SEMICONDUCTOR WAFERSjmicro
Accurate modeling of light scattering from nanometer scale defects on Silicon wafersiscritical for enabling
increasingly shrinking semiconductor technology nodes of the future. Yet, such modeling of defect
scattering remains unsolved since existing modeling techniques fail to account for complex defect and
wafer geometries. Here, we present results of laser beam scattering from spherical and ellipsoidal
particles located on the surface of a silicon wafer. A commercially available electromagnetic field solver
(HFSS) was deployed on a multiprocessor cluster to obtain results with previously unknown accuracy
down to light scattering intensity of -170 dB. We compute three dimensional scattering patterns of silicon
nanospheres located on a semiconductor wafer for both perpendicular and parallel polarization and show
the effect of sphere size on scattering. We further computer scattering patterns of nanometer scale
ellipsoidal particles having different orientation angles and unveil the effects of ellipsoidal orientation on
scattering.
MODELING STUDY OF LASER BEAM SCATTERING BY DEFECTS ON SEMICONDUCTOR WAFERSjmicro
Accurate modeling of light scattering from nanometer scale defects on Silicon wafersiscritical for enabling
increasingly shrinking semiconductor technology nodes of the future. Yet, such modeling of defect
scattering remains unsolved since existing modeling techniques fail to account for complex defect and
wafer geometries. Here, we present results of laser beam scattering from spherical and ellipsoidal
particles located on the surface of a silicon wafer. A commercially available electromagnetic field solver
(HFSS) was deployed on a multiprocessor cluster to obtain results with previously unknown accuracy
down to light scattering intensity of -170 dB. We compute three dimensional scattering patterns of silicon
nanospheres located on a semiconductor wafer for both perpendicular and parallel polarization and show
the effect of sphere size on scattering. We further computer scattering patterns of nanometer scale
ellipsoidal particles having different orientation angles and unveil the effects of ellipsoidal orientation on
scattering.
This document discusses microfabrication processes used to manufacture microelectromechanical systems (MEMS) and microsystems. It describes that traditional machine tools cannot be used at the microscale, so physical-chemical processes developed for integrated circuits are adopted. Key microfabrication processes discussed include photolithography, ion implantation, diffusion, oxidation, deposition, and etching. Photolithography involves using a photosensitive film and optical image to produce patterns on a substrate. Ion implantation and diffusion are methods for doping silicon substrates with dopants like boron and phosphorus. Fick's laws of diffusion and the diffusion equation are provided to analyze dopant distribution over time.
About The Importance Of The Definition Of Reflectance Quantities-Results Of C...Jim Webb
1) The document discusses the importance of properly defining reflectance quantities used in remote sensing studies. It notes inconsistencies in how terms like "albedo" have been used in different studies.
2) It summarizes definitions of key reflectance terms like BRDF, BRF, DHR, HDRF, and provides examples of measurable versus conceptual quantities.
3) Case studies are presented comparing modeling results for directional versus hemispherical reflectance quantities for a black spruce forest canopy and snow cover, as well as MISR satellite data products, to demonstrate differences between these reflectance definitions.
Analysis of the_optical_density_profile_of_otolith_of_icefishryszardtraczyk
The document analyzes optical density profiles of otoliths from two fish species, Ps. georgianus and Ch. gunnarii, using computer measurement and harmonic analysis to investigate daily and other increments. For Ps. georgianus, the average width of daily larval otolith increments was 9.41 * 10-4 mm, while for juvenile Ch. gunnarii it was 0.0024 mm. Cyclical increments in larval Ps. georgianus otoliths followed a sine wave pattern.
The document describes the FAST (Fluorescence detector Array of Single-pixel Telescopes) project. FAST aims to measure ultra-high energy cosmic rays above 1019.5 eV using an array of single-pixel telescopes to detect air fluorescence. Each FAST station would have 12 telescopes covering a 30°×360° field of view. With 500 stations spaced 20 km apart over 150,000 km2, FAST could detect over 5,000 events per year above 57 EeV and 650 above 100 EeV. Prototype FAST telescopes have been installed and observed laser shots and cosmic ray air showers in coincidences with the Telescope Array fluorescence detector.
- The document discusses using a flame synthesis technique called flame stabilization on a rotating surface (FSRS) to produce TiO2 nanoparticles and thin films for use in dye-sensitized solar cells (DSSCs).
- FSRS allows for one-step particle synthesis and film deposition, controlling properties like particle size and crystal phase that impact DSSC efficiency. DSSCs made with FSRS-produced films show efficiencies up to 7.6%.
- Parameters like particle size, crystal phase, thickness, and surface area can be controlled in FSRS and significantly impact DSSC performance. Smaller particles and the anatase crystal phase produce higher photocurrents and efficiencies.
Synthesis and characterisation of k doped zno 1Jeslin Mattam
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Microscopy microanalysis microstructures_the european physical journal_applie...Andrea Sentimenti
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We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
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Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
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Exposé invité Journées Nationales du GDR GPL 2024
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Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
2. • Soiling Overview
• Ångström formula
• Experimental Procedure
• Transmission Results
• Coupon vs. PV Module
• Angle of Incidence effects
– Model vs. Experiments
• Conclusions
Outline
Ambient Particulates
(PM)
Deposited PM Reduces
Transmittance to PV
Graphic: M.H. Bergin et al, Duke University, Durham, NC
3. Ambient Particulates
(PM)
Deposited PM Reduces
Transmittance to PV
Graphic: M.H. Bergin et al, Duke University, Durham, NC
"Large Reduc>ons in
Solar Energy
Produc>on Due to
Dust and Par>culate
Air Pollu>on", Mike H.
Bergin, Chinmay
Ghoroi, Deepa Dixit,
James J. Schauer, and
Drew T. Shindell,
Environ. Sci. Technol.
LeX., 2017.
6. Defini#on of Par#culate MaBer
ø < 10
um ø < 2.5
um
Particulate matter (PM): concentration (µg/m3) of solid
particles and liquid droplets suspended in 1 m3 of air.
PM10 Sources:
Crushing or grinding
operations
Dust stirred up by
vehicles on roads
PM2.5 Sources:
Motor vehicles,
power plants,
residential wood
burning, forest
fires, agricultural
burning, industrial
processes.
Source: https://www.airnow.gov/index.cfm?action=aqibasics.particle6
7. PV EL and Soiling
associated with a more constant voltage potential between the
external glass surface and the active cell circuit of the
module—but lower net current magnitude [17].
a
b
Fig. 4. Subtractive electroluminescence images taken at 4.1-A
forward-bias current on module type A with salt; (a), 73.3% power
remaining; (b) without salt, 84.7% power remaining. Degraded
areas appear dark.
Peter Hacke, et al, Effects of
Photovoltaic Module Soiling on
Glass Surface Resistance and
Potential-Induced Degradation,
Conference Paper, NREL/
CP-5J00-64492 December 2015
7
8. Diagram Courtesy of Al Hicks, NREL8
The Optical Path of the Light (clean vs. soiled)
9. Particle size is smaller
than one- tenth the
wavelength of light
DIFFUSE
(a) RAYLEIGH SCATTERING
Particle size is
approximately
one-fourth the
wavelength
of light
DIFFUSE
Particle size is
larger than the
wavelength
of light
(b) MIE SCATTERING
An Introduction to Solar Radiation,
Muhammad Iqbal, Academic Press,
New York, 1983, Chapter 6.
Atmospheric Scattering
9
can be applied to
particles on the glass
10. β → 0.0 to 0.5 or even higher
• An index representing the
amount of aerosols (particles)
present
• Wavelength (λ) exponent
• Generally 0.5 to 2.5 (Ångström suggested 1.3)
ma is the optical path length
Ångström turbidity formula
𝛼=4 for small non-absorbing particles
𝛼=1 for small absorbing particles
𝛼=0 for large particles
10
12. Experimental procedure
- Seven 4 cm x 4 cm x 3 mm-thick low iron glass coupons shipped to
each location.
- Coupon 1 to 6 installed outdoors at zero tilt angle for eight weeks.
- Coupon 0 kept in a dust free container and used to calibrate each
spectrophotometer.
- Weekly transmission measurements for coupons 1, 2, 3.
- Daily weather and particulate matter (PM) concentration recorded.
- A dry cleaning is performed by using a microfiber cleaning cloth.
• Coupon 1 cleaned every week, Coupon 2 every four weeks.
12
14. Ångström equation returns in both cases high R2 (≥90%), and low RMSE (<0.3%).
Fidng San José and Chennai Data
(aaer 8 weeks)
15. Ångström equation returns in both cases high R2 (≥90%), and low RMSE (<0.3%).
…but fitting at low wavelengths can still be improved.
Fidng San José and Chennai Data
(aaer 8 weeks)
15
16. First results
Absolute direct and hemispherical transmittance of coupon 3 in Golden,
CO. Wavelengths between 500 and 1100 nm have been averaged.
17. Hemispherical transmittance (8 weeks)
Hemispherical transmittance in the visible and NIR range of coupon 5 for all the sites
(above) and for the low soiling sites (below), referenced to the transmittance of
coupon 0. The spectra were measured using a PerkinElmer Lambda 1050 UV/Vis
spectrophotometer with a 150 mm integrating sphere at NREL and processed using a
local regression technique to remove noise.
18. Par>cle Area and Hemispherical TransmiXance
• Average particle area was determined by high resolution optical
microscopy.
• Percentage of the surface covered by particles was estimated.
• A linear correlation, with R2 higher than 0.99, is found by comparing the
percentage area covered by particles to the hemispherical transmission.
• The broadband hemispherical transmission could be directly obtained from
the coverage area, independently of location, dust type and composition.
• See the subsequent plot (slide).
• Broadband hemispherical transmittance (300-2500 nm)
was measured.
18
19. Fractional Loss versus Particle Coverage
5% 10% 15% 20% 25% 30% 35% 40%
0%
5%
10%
15%
20%
25%
FractionalParticleCoverage
Fraction Loss
slope = 0.80±0.02
R2
= 0.99
19
20. The Dust & Rain in Spain falls mainly…
Predication: 6-months of outdoor exposure at Jáen, Spain.
Estimated weekly evolution of Soiling Ratio index estimated for three PV materials.
20
From the transmission of glass coupons times the solar spectrum times the PV spectral response or QE. There was a
Saharan dust storm at week 6 and then rain.
21. 28 Chapter 2
Fig. 2.10 Geometry for calculation of the absorptivity from a polished (left side) and
textured (right side) light absorber. In each case, a summation of multiple reflections must
be made in order to calculate the absorptivity. The angle q is measured from the surface
normal.
These equations can be used to predict the reflectivity, otherwise known as
the reflection coefficient, of a solar cell absorber material. The index of n value
for Si, for example, is approximately 4 at a wavelength of 600 nm (see Fig. 2.3).
Library of Congress Cataloging-in-Publication Data
Smestad, Greg P.
Optoelectronics of solar cells / by Greg P. Smestad.
p. cm.-- (SPIE Press monograph ; PM115)
Includes bibliographical references and index.
ISBN 0-8194-4440-5 (softcover)
1. Solar cells. 2. Optics. I. Title. II. Series.
or soiled
Op>cs of a PV Module (right) does not
match that of the coupons (lea)
or clean
glass
air
22. iθ
rθ
rφ
i 180φ = °
rdΩ
β
Angular Measurements and Model
scattering azimuth
or
“out-of-plane
scattering angle”
scattering angle
incident angle
differential
solid angle
incident azimuth
sample rotation
Thomas A. Germer, Sensor Science Division, NIST
23. Describing the scaBer from a
delocalized scaBerer
The Bidirectional Scattering Distribution Function
(BSDF) is the fraction of power scattered per unit
projected solid angle.
r
r
0
i r
lim
cos
P
f
P θ→Ω Ω
= [sr-1]
Scattered
power [W]
Incident power [W]
Solid angle [sr]
Polar scattering
angle
Thomas A. Germer, Sensor Science Division, NIST23
24. IEST-STD-CC 1246E Distribution
The cumulative distribution is
the number of particles between
1 µm and D. Shown here are
the distribution density, dN(D)/
dD, and the distribution density
weighted by area and volume.
Notice how much the peak
appears to change. It is hard to
eyeball a peak size in a
distribution from an image.
1 10 100 1000
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
NormalizedDistributionDensity
D / µm
N(D)
N(D) D2
N(D) D3
Thomas A. Germer, NIST 24
25. -90° -60° -30° 0° 30° 60° 90°
10- 5
10
- 4
10- 3
10
- 2
10- 1
10
0
101
10
2
103
10
4
105
C7
C3D
Control
Model
BTDF/sr-1
θt
The Transmission Data (San José)
Thomas Germer, NIST25
26. Reflectance for collimated incident light
Ωr
With a lot of experimental geometries, the incident light is close
to collimated. Then, the reflectance is
r
r
i i r r i i r r r
r r r r r
r
i i r r
( , ; ) ( , ; , ) cos d
d d sin cos ( , ; , )
f
f
ρ θ φ θ φ θ φ
θ φ θ θ φ φ
θ
θ θ
Ω
Ω
=Ω Ω
=
∫
∫
Program INTEGRATED.MIST calculates the hemispherical
reflectance for any BRDF model. Thomas A. Germer, NIST
27. -90° -60° -30° 0° 30° 60° 90°
10- 4
10
- 3
10
- 2
10- 1
10
0
10
1
102
10
3
10
4
105
2.5°
70°
60°C7
Model
BRDF/sr-1
θs
45°
The Reflection data
Thomas A. Germer, NIST
28. 0° 30° 60° 90°
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
ρ(θi
,2π)
θi
specular reflectance of glass
IEST-STD-CC 1246E
Cleanliness 1000
Predicted Reflectivity vs incidence angle
Thomas A. Germer, NIST28
29. 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
0.026
0.027
0.028
0.029
0.030
0.031
0.032
ρ(θi
,2π)
λ / µm
Calculated Hemispherical Reflectance of Soot Particles
Using IEST-STD-CC 1246E Distribution Cleanliness 1000
Thomas Germer, NIST29
30. Conclusions (Optics of PV soiling)
• Estimating soiling losses using the transmission from glass
coupons may not easily translate to knowledge about
power losses from PV modules.
• The affect on direct transmission is greater than
hemispherical.
• There is a linear correlation between the area covered by
particles and the broadband hemispherical transmittance.
• Soiling produces a higher attenuation at shorter
wavelengths (Ångström turbidity formula) compared to
longer wavelengths.
• The impact of soiling is likely higher on PV materials with
larger bandgap (a-Si, CdTe).
• Soiling Losses are certainly a function of input angle.
31. • EPSRC SUPERGEN SuperSolar Hub’s “International and
industrial engagement fund” for the project “Global investigation
on the spectral effects of soiling losses”
• University of Exeter, UK; National Renewable Energy Laboratory
(NREL), USA; University of Jáen, Spain; Sol Ideas Technology
Development, San José (CA), USA; Tezpur University, Tezpur,
India; Robert Gordon University, Aberdeen, UK; South Valley
University, Qena, Egypt; British University in Egypt, El Sherouk
City, Egypt; BITS Pilani, Dubai Campus, Dubai, UAE; Academy of
Scientific and Innovative Research, Chennai, India; CSIR-Central
Electronics Engineering Research Institute, Chennai, India; Indian
Institute of Technology Madras, Chennai, India.
Acknowledgments
Greg P. Smestad, Sol Ideas Technology Development
smestad@solideas.com — www.solideas.com
32. The International PV Quality Assurance Task Force
(PVQAT, "PV cat”) TG-12. Website: http://www.pvqat.org
Soiled Residential PV System of David Bernal
in Los Angeles (Photo by Greg Smestad)
Greg P. Smestad, Sol Ideas
Technology Development
smestad@solideas.com —
www.solideas.com
33. Background, Supporting Information
Leonardo Micheli, Eduardo F. Fernández, Greg P. Smestad, et
al, "A unique global investigation on the spectral effects of
soiling losses of PV glass substrates: preliminary results".
• Paper & Poster available
• Presented at ieee-pvsc.org/PVSC44/
• Download the materials for free here:
http://www.solideas.com/projects/pvquality/index.html
35. 6.2 Attenuation of Direct Solar Radiation 109
/ *Οηλ
Figure 6.2.2 Attenuation of direct radia-
tion through a homogeneous atmosphere.
J χ
ηλ
or Beer's law. According to Bouguer's law, the attenuation of light through a
medium is proportional to the distance traversed in the medium and to the
local flux of radiation. This simple law applies in most instances (with the
exception of absorption by gases), whether the energy is absorbed or scat-
tered. Moreover, this law applies to monochromatic radiation only. In terms
of this law,
4A = A)nAexp(-/cAm), (6.2.1)
where
kx is the monochromatic extinction or attenuation coefficient,
m is the optical path length, and
kxm is the monochromatic extinction optical thickness3
(dimensionless).
Bouguer's law - the attenuation
of light through a medium is
proportional to the distance
traversed in the medium.
kλ is the monochromatic
extinction or attenuation
coefficient
m is the optical path length
kλm is the monochromatic
extinction optical thickness
particularly useful when one or more of the atte
not obey the simple Bouguer's law. The monoch
ue to direct radiation can be written as
^ = r L
= ΪΊΚΑ,
transmittance due to a single process i and τλ is due t
ined. The transmittance due to a single process is g
τίλ = exp(-feamI).
w accurately represents attenuation processes of scAn Introduction to Solar Radiation, Muhammad Iqbal, Academic Press, New York, 1983, Chapter 6.
3
5
36. Figure 6,6,1 Variation of the horizontal visibility with a and ß.
I.OP
* 0.8
Id
U
i 0.6
Z
<
O 0.4
o
£T
UJ
<
0 . 2 h
0.0
L^^^^^iSm « 0.05
Γ x
•"
•
•
J ^.-~
-■»
«^* ^«-~·-"""~
l· " ^-^*
^-~—-·"""
ψΛ
--*·*^
1 ^>^ „--' / ?s^ / ' ^.
L x' ' ^ϊ^Γ X / X ^^<^/ / ' ^ ^ ' '/ ' s ^*^ *'
/ ' ~ <ί^^ ^
r/ / ^>^^ / ^^/ / ^^ ' ^*—
Ϊ / /? /^'^Γ / / ' '^^
/ / ' ' %έ^1 / / / Jr / / /^y a = 0.7
ψ /<>' —.-..31 ^* s
st '{ySS *
I'-*' 1 1 1 t 1 1 1 _L
^***^
~Ί
0.4 2 . 00.8 1.2 1.8
WAVELENGTH ( p )
Figure 6,6,2 Aerosol spectral transmittance as a function of a and ßm.
An Introduction to Solar Radiation, Muhammad Iqbal, Academic Press, New York, 1983, Chapter 6.
37. First results: Coupon 5 (2 months of outdoor exposure)
Broadband hemispherical transmittance (300-2500 nm), average particle area,
and percentage of the surface covered by particles, measured at the end of the
data collection. Unsoiled PV glass transmittance is 90.4%
• A linear correlation, with R2 higher than 0.99, is found by comparing the
percentage area covered by particles to the hemispherical transmission
• The broadband hemispherical transmission could be directly obtained from
the covered area, independently of dust type and composition.