scholarly journals 04/02902 Solar position algorithm for solar radiationapplications

2004 ◽  
Vol 45 (6) ◽  
pp. 410
Keyword(s):  
Solar Position

Solar Tracking Device Based on Electronic Compass and Accelerometer

2014 ◽  
Vol 981 ◽  
pp. 522-525 ◽  
Author(s):  
Zhong Ran Zhang ◽  
Yuan Ma ◽  
Bo Jiao ◽  
Tong Liang Liu
Keyword(s):  
Elevation Angle ◽  
Least Square Method ◽  
Least Square ◽  
Stable Operation ◽  
Solar Tracking ◽  
High Flexibility ◽  
Tracking Device ◽  
Solar Position ◽  
Electronic Compass ◽  
The Magnetic Field

A solar tracking device was designed in this paper. First, In order to determine the initial direction of the mechanism and the east, HMC5883L was used for measuring the magnetic field of earth. Then, the mechanism began to operate according to the solar position which was confirmed though the astronomical calculation. Finally, the azimuth and the elevation angle of solar were measured and corrected by HMC5883L and MPU6050 respectively. HMC5883L was calibrated by the ellipse fitting, which was obtained though the least square method. The horizontal error of HMC5883L was compensated. The experimental study was performed. And the results show that the solar tracking device has the characteristics of stable operation, high flexibility and low requirement of installation precision.

An algorithm for the computation of the solar position

Solar Energy ◽  
2008 ◽  
Vol 82 (5) ◽  
pp. 462-470 ◽  
Author(s):  
Roberto Grena
Keyword(s):  
Solar Position

scholarly journals VISIBILITY MONITORING USING MOBILE APPLICATION

2018 ◽  
Vol XLII-5 ◽  
pp. 883-891
Author(s):  
S. Purohit ◽  
P. Chauhan
Keyword(s):  
Mobile Application ◽  
Smart Phone ◽  
Quantitative Measure ◽  
Weather Conditions ◽  
Optical Instruments ◽  
Important Concern ◽  
Transport Safety ◽  
Continuous Power ◽  
Variable Weather ◽  
Solar Position

<p><strong>Abstract.</strong> Visibility is clarity with which the distant objects are perceived in the atmosphere with the naked eye. Visibility monitoring is an important concern in health, environment and transport safety context. Quantitative measures of visibility are increasingly becoming important in various areas as they are representative of the particles present in the environment that causes degradation of the visibility. Existing techniques of visibility estimation employ human observers, optical instruments, chemical sensors or combination of some of them. These techniques suffer from poor spatial and temporal resolution, high cost of installation and maintenance, need of specialized personnel, continuous power supply requirement and difficulty in portability. We propose a smart phone-based visibility monitoring system which estimates air visibility/quality in terms of a quantitative measure: Turbidity. In principle, the application calculates turbidity as difference of intensity of captured sky image and analytical value of sky luminance obtained by implementing Perez model. The estimated turbidity tagged with date, time, location, solar position and luminance is sent to the backend server generating consolidated database for mapping of turbidity and generating various analytical reports. The application can easily be deployed to be used by large number of people facilitating citizen science. The results from application were validated against the observations from SAFAR INDIA application at different stations in Ahmedabad, dates and under variable weather conditions.</p>

scholarly journals ASDToolkit: A Novel MATLAB Processing Toolbox for ASD Field Spectroscopy Data

2020 ◽  
Author(s):  
Kathryn Elmer ◽  
Raymond Soffer ◽  
J. Pablo Arroyo-Mora ◽  
Margaret Kalacska
Keyword(s):  
Individual Characteristics ◽  
Atmospheric Conditions ◽  
Current Effort ◽  
Data Product ◽  
Field Spectroscopy ◽  
The Individual ◽  
Solar Position ◽  
Derived Data

Over the past 30 years, the use of field spectroscopy has risen in importance in remote sensing studies for the characterization of the surface reflectance of materials in situ within a broad range of applications. Potential uses range from measurements of individual targets of interest (e.g. vegetation, soils, validation targets etc.), to characterizing the contributions of different materials within larger spatially-mixed areas as would be representative of the spatial resolution captured by a sensor pixel (UAV to satellite scale). As such, it is essential that a complete and rigorous assessment of both the data-acquisition procedures, and the suitability of the derived data product be carried out. The measured energy from solar-reflected range spectroradiometers is influenced by the viewing and illumination geometries and the illumination conditions which vary due to changes in solar position and atmospheric conditions. By applying corrections, the estimated absolute reflectance (Rabs) of targets can be calculated. This property is independent of illumination intensity or conditions and is the metric commonly suggested to be used to compare spectra even when data are collected by different sensors or acquired under different conditions. By standardizing the process of estimated Rabs, as is provided in the described toolkit, consistency and repeatability in processing are ensured and the otherwise labor intensive and error-prone processing steps are streamlined. The resultant end data product (Rabs) represents our best current effort to generate consistent and comparable ground spectra which have been corrected for viewing and illumination geometries as well as other factors such as the individual characteristics of the reference panel used during acquisition.

scholarly journals First Gaia dynamical model of the Milky Way disc with six phase space coordinates: a test for galaxy dynamics

2020 ◽  
Vol 494 (4) ◽  
pp. 6001-6011 ◽  
Author(s):  
Maria Selina Nitschai ◽  
Michele Cappellari ◽  
Nadine Neumayer
Keyword(s):  
Phase Space ◽  
Milky Way ◽  
Dynamical Model ◽  
Total Density ◽  
Dark Halo ◽  
Stellar Kinematics ◽  
Galaxy Dynamics ◽  
Dispersion Tensor ◽  
External Galaxies ◽  
Solar Position

ABSTRACT We construct the first comprehensive dynamical model for the high-quality subset of stellar kinematics of the Milky Way disc, with full 6D phase-space coordinates, provided by the Gaia Data Release 2. We adopt an axisymmetric approximation and use an updated Jeans Anisotropic Modelling (JAM) method, which allows for a generic shape and radial orientation of the velocity ellipsoid, as indicated by the Gaia data, to fit the mean velocities and all three components of the intrinsic velocity dispersion tensor. The Milky Way is the first galaxy for which all intrinsic phase space coordinates are available, and the kinematics are superior to the best integral-field kinematics of external galaxies. This situation removes the long-standing dynamical degeneracies and makes this the first dynamical model highly overconstrained by the kinematics. For these reasons, our ability to fit the data provides a fundamental test for both galaxy dynamics and the mass distribution in the Milky Way disc. We tightly constrain the volume average total density logarithmic slope, in the radial range 3.6–12 kpc, to be αtot = −2.149 ± 0.055 and find that the dark halo slope must be significantly steeper than αDM = −1 (NFW). The dark halo shape is close to spherical and its density is ρDM(R⊙) = 0.0115 ± 0.0020 M⊙ pc−3 (0.437 ± 0.076 GeV cm−3), in agreement with previous estimates. The circular velocity at the solar position vcirc(R⊙) = 236.5 ± 3.1 km s−1 (including systematics) and its gently declining radial trends are also consistent with recent determinations.

scholarly journals Distribution and kinematics of 26Al in the Galactic disc

2020 ◽  
Vol 497 (2) ◽  
pp. 2442-2454 ◽  
Author(s):  
Yusuke Fujimoto ◽  
Mark R Krumholz ◽  
Shu-ichiro Inutsuka
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Spiral Structure ◽  
Rotation Speed ◽  
Scale Height ◽  
Stellar Winds ◽  
Galactic Disc ◽  
Stellar Feedback ◽  
Self Gravity ◽  
Solar Position

ABSTRACT 26Al is a short-lived radioactive isotope thought to be injected into the interstellar medium (ISM) by massive stellar winds and supernovae (SNe). However, all-sky maps of 26Al emission show a distribution with a much larger scale height and faster rotation speed than either massive stars or the cold ISM. We investigate the origin of this discrepancy using an N-body + hydrodynamics simulation of a Milky-Way-like galaxy, self-consistently including self-gravity, star formation, stellar feedback, and 26Al production. We find no evidence that the Milky Way’s spiral structure explains the 26Al anomaly. Stars and the 26Al bubbles they produce form along spiral arms, but, because our simulation produces material arms that arise spontaneously rather than propagating arms forced by an external potential, star formation occurs at arm centres rather than leading edges. As a result, we find a scale height and rotation speed for 26Al similar to that of the cold ISM. However, we also show that a synthetic 26Al emission map produced for a possible Solar position at the edge of a large 26Al bubble recovers many of the major qualitative features of the observed 26Al sky. This suggests that the observed anomalous 26Al distribution is the product of foreground emission from the 26Al produced by a nearby, recent SN.

scholarly journals Application of Photocatalytic Concrete Paving Blocks in Poland—Verification of Effectiveness of Nitric Oxides Reduction and Novel Test Method

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5183
Author(s):  
Hubert Witkowski ◽  
Janusz Jarosławski ◽  
Anna Tryfon-Bojarska
Keyword(s):  
Test Method ◽  
Light Irradiation ◽  
Nitric Oxides ◽  
Field Campaign ◽  
Airborne Pollutants ◽  
The Past ◽  
Nitric Oxide Reduction ◽  
Photocatalytic Concrete ◽  
Solar Position ◽  
Investigation Process

Photocatalytic concrete is one of the most promising concrete technologies of the past decades. Application of nanometric TiO2 to cement matrices enables the reduction of harmful airborne pollutants. Although a number of implementations of this technology are described in this paper, problems related to test conditions are also reported. One major issue is the sufficient light irradiation that for higher latitudes can be significantly reduced. In this paper, a field campaign on the implementation of photocatalytic concrete pavement in Warsaw (52.23° N) is briefly described. Based on experience from the field campaign, a novel test method is developed. In the research, the effectiveness of nitric oxide reduction is verified at natural light irradiation for various dates of solar position at noon in central Poland (51.83° N). The results confirm the benefits of using photocatalytic materials at higher latitudinal locations. The experimental setup presented in the study combines the advantages of controlled measurement conditions typical in laboratory tests with the possibility of including natural sunlight conditions in the investigation process.

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