Heliostat Characterization by Optical Techniques and Image Processing

Author(s):  
Manuel I. Peña-Cruz ◽  
Camilo A. Arancibia-Bulnes ◽  
Cuitlahuac Iriarte-Cornejo ◽  
Rafael E. Cabanillas ◽  
Claudio A. Estrada

In the framework of the National Laboratory of Solar Concentrating and Solar Chemistry Systems (LACYQS, for its Spanish acronym), a Heliostat Test Field (HTF) was built in México. This research facility is located 10 km away from the city of Hermosillo, in the state of Sonora. The main purpose of the HTF, at the present stage, is to serve as platform for the development and testing of heliostat technology. In order to evaluate the performance of heliostats, various optical tests have been implemented. In the sun tracking test, the heliostat is operated as a solar tracker. A camera is attached to the heliostat, which is pointed directly to the sun. Images are captured throughout the day to quantify the wandering of the solar disc in the image. In the reflected spot test, the image produced on the Lambertian target by the concentrating heliostat, due to the reflection of the sun, is recorded by a CCD camera throughout the day. Image processing algorithms calculate the centroid of energy of the image and evaluate the position and wandering across the white screen at all times. After this information is gathered, and the influence of wind and external factors eliminated, data are interpreted to characterize the behavior of solar projection algorithms and mechanical components. In the fringe projection analysis, also known as deflectometry, fringe patters are projected at night on a Lambertian target. The image of the pattern reflected by the heliostat is recorded with a camera. Distortions in the fringes, due to mirror stress and canting, allows the characterization of the surface error of the facets.

Author(s):  
D. L. Beshears ◽  
G. J. Capps ◽  
D. D. Earl ◽  
J. K. Jordan ◽  
L. C. Maxey ◽  
...  

As part of the design and development effort for the “Hybrid Lighting System,” Oak Ridge National Laboratory (ORNL) scientists have evaluated two potential candidate-tracking systems for the solar collector. The first system, the WattSun Solar Tracker, built by Array Technologies, utilizes a patented, closed loop, optical sun sensor to sense the sun’s position and track it. The second tracking system, SolarTrak Controller, built by Enhancement Electronics, Inc., is a micro controller-based tracking system. The SolarTrak micro controller-based Tracker’s sun position is determined by computing the celestial bearing of the sun with respect to the earth using the local time, date, latitude, longitude and time zone rather than sensing the relative bearing of the sun with optical receptors. This system connects directly to the mechanical system hardware supplied by Array Technologies. Both the WattSun Solar Tracker and the SolarTrak Controller were mounted on the prototype “Hybrid Lighting” mechanical system (array) hardware. A simple switch allowed independent testing of each system. Upon completion of the evaluation of the two systems we found the WattSun Solar Tracker controller to be unacceptable for use with our prototype hybrid lighting system. The SolarTrak Controller has performed well to date and provides suitable tracking accuracy for use with our prototype “Hybrid Lighting System”. After a six-month evaluation period at ORNL, the first prototype “Hybrid Lighting System” was installed at Ohio University as part of an “Enhanced Practical Photosynthetic CO2 Mitigation.” This document will highlight the results of the tracker investigation and outline the remaining issues to be addressed, to provide a suitable tracking system for our “Hybrid Lighting” collector.


2017 ◽  
Vol 866 ◽  
pp. 41-44
Author(s):  
Paisan Kanthang

MinD proteins play important roles during cell division process. These proteins show significant characteristics of periodic pole-to-pole propagation along the cell length. The characterizations of these protein behaviors are required to be determined accurately. Usually by using a fluorescent technique, visual motion of proteins in the cell could possibly be made and observed through a CCD. Due to the nature of low intensity of these proteins, the images obtained from the CCD camera were required to subject to noise interference and as a result digital image processing was also required. In this paper, several techniques were tried to facilitated improve the image quality. From our finding, the fluorescent technique could affect the intensity fading of the protein detected, but not to the numbers of the proteins in the cell.


Author(s):  
Weiping Liu ◽  
Jennifer Fung ◽  
W.J. de Ruijter ◽  
Hans Chen ◽  
John W. Sedat ◽  
...  

Electron tomography is a technique where many projections of an object are collected from the transmission electron microscope (TEM), and are then used to reconstruct the object in its entirety, allowing internal structure to be viewed. As vital as is the 3-D structural information and with no other 3-D imaging technique to compete in its resolution range, electron tomography of amorphous structures has been exercised only sporadically over the last ten years. Its general lack of popularity can be attributed to the tediousness of the entire process starting from the data collection, image processing for reconstruction, and extending to the 3-D image analysis. We have been investing effort to automate all aspects of electron tomography. Our systems of data collection and tomographic image processing will be briefly described.To date, we have developed a second generation automated data collection system based on an SGI workstation (Fig. 1) (The previous version used a micro VAX). The computer takes full control of the microscope operations with its graphical menu driven environment. This is made possible by the direct digital recording of images using the CCD camera.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amy Gaye ◽  
Tolla Ndiaye ◽  
Mouhamad Sy ◽  
Awa B. Deme ◽  
Alphonse B. Thiaw ◽  
...  

AbstractDengue virus is a major and rapidly growing public health concern in tropic and subtropic regions across the globe. In late 2018, Senegal experienced its largest dengue virus outbreak to date, covering several regions. However, little is known about the genetic diversity of dengue virus (DENV) in Senegal. Here we report complete viral genomes from 17 previously undetected DENV cases from the city of Thiès. In total we identified 19 cases of DENV in a cohort of 198 individuals with fever collected in October and November 2018. We detected 3 co-circulating serotypes; DENV 3 was the most frequent accounting for 11/17 sequences (65%), 4 (23%) were DENV2 and 2 (12%) were DENV1. Sequences were most similar to recent sequences from West Africa, suggesting ongoing local circulation of viral populations; however, detailed inference is limited by the scarcity of available genomic data. We did not find clear associations with reported clinical signs or symptoms, highlighting the importance of testing for diagnosing febrile diseases. Overall, these findings expand the known range of DENV in Senegal, and underscore the need for better genomic characterization of DENV in West Africa.


2019 ◽  
Vol 34 (4) ◽  
pp. 419-437 ◽  
Author(s):  
Roberto Rocco ◽  
Luciana Royer ◽  
Fábio Mariz Gonçalves

2017 ◽  
Vol 864 ◽  
pp. 224-228
Author(s):  
Seung Hyeon You ◽  
Jeong Hwan Lee ◽  
Sung Hoon Oh

This study has developed street lamp lighting device material that was turned on and off by self-power supply without additional power by using the rays of the sun. Lighting devices have been applied with polycarbonate materials that were outstanding with light transmissivity while using LED light and economic value. Lighting devices are easily installed in various places since external power is not necessary. In addition, it also serves as a function of preventing crime by acquiring intensity of illumination in crime-ridden district in the night. Lighting device can also serve as a function of improving fine view in the city by establishing eco-friendly circumstances including parks, areas around shopping district, and housing areas after being manufactured in the form of flowerpot where can grow plants in the future.


2007 ◽  
Vol 1047 ◽  
Author(s):  
Eleni Pavlidou ◽  
N. Civici ◽  
E. Caushi ◽  
L. Anastasiou ◽  
T. Zorba ◽  
...  

AbstractIn this paper are presented the studies of the paint materials and the technique used in 18th century wall paintings, originated from the orthodox church of St Athanasius, in the city of Maschopolis, a flourishing economical and cultural center, in Albania. The church was painted in 1745 by Konstantinos and Athanasios Zografi, and during the last years, restoration activities are being performed at the church. Samples that included plasters and pigments of different colors were collected from important points of the wall paintings. Additionally, as some parts of the wall-paintings were over-painted, the analysis was extended to the compositional characterization of these areas. The identification of the used materials was done by using complementary analytical methods such as Optical Microscopy, Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM-EDS) and X-ray fluorescence (TXRF).The presence of calcite in almost all the pigments is indicative for the use of the fresco technique at the studied areas, while the detection of gypsum and calcium oxalate, indicates an environmental degradation along with a biodegradation. Common pigments used in this area at 15-16th centuries, such as cinnabar, green earth, manganese oxide, carbon black and calcite were identified.


2021 ◽  
Vol 13 (6) ◽  
pp. 3272
Author(s):  
Paúl Carrión-Mero ◽  
Maribel Aguilar-Aguilar ◽  
Fernando Morante-Carballo ◽  
María José Domínguez-Cuesta ◽  
Cristhian Sánchez-Padilla ◽  
...  

In the last decade, in the mining district of Zaruma-Portovelo, there has been significant land subsidence related to uncontrolled mining activity. The purpose of this work was to carry out a surface and underground geomechanical characterization of a mining sector north of the city of Zaruma that allows the definition of potentially unstable areas susceptible to the mass movement. The methodology used consists of the following stages: (i) compilation of previous studies; (ii) surface and underground characterization of rocky material to establish its susceptibility to mass movement; (iii) interpretation of results; and (iv) proposal of action measures. Among the most relevant results, it stands out that 26.1% of the 23 stations characterized on the surface present conditions that vary from potentially unstable to unstable. In underground galleries, the studied mean values of the 17 stations indicate that the rock has a medium to good quality, representing a medium susceptibility to gallery destabilization. The results obtained for the surface areas (depths up to 50 m, where altered materials predominate) and the underground areas (depths > 50 m, where the alterations are specific) can be used to identify the areas with a more significant potential for instability. For both cases, it has been possible to define specific monitoring, control, and planning actions for sensitive areas.


2013 ◽  
Vol 321-324 ◽  
pp. 1138-1144
Author(s):  
Chao Liu ◽  
Jing Hui

Based on analyzing the development and the performance feature of existing solar tracker, we propose a solar Maximum Power Point Tracking (MPPT) strategy which combines photoelectric sensor and image processing. Firstly, photoelectric tracking mode positions the sun in the field of view of the image sensor. Then, the position of the sun image is captured by the image sensor. After that, we can find the coordinates of the sun spot in the field of view through image binarization processing. According to the number of steps of stepper motor rotation which is calculated by the deviation of coordinates, the controller drives the biaxial photosensitive (PV) array tracking device, making the sun spot always fall in the centre of the image. Tests show that the elevation angle and azimuth angle of the tracking range of the photovoltaic array are both 0~270°.The average tracking error of elevation angle is less than 0.7°, and the average tracking error of azimuth angle is less than 0.5°.


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