Tres arquitecturas neuronales implementadas en la detección y categorización de anomalías en paneles fotovoltaicos

Solar panels are useful and efficient tools. They need to be kept in excellent working condition, but as time goes by, they suffer from external failures manifested in the environment. Therefore, the need for effective monitoring of such systems is highlighted. Neural models are perfect candidates to perform physical damage recognition. In this case, we compare the performance of three artificial neural networks, the multilayer perceptron, the densely connected neural network, and the ResNet-50 network in this identification problem. What is intended to be obtained from this method is the practical demonstration of the use of neural networks to solve real problems.Los paneles solares son herramientas útiles y eficientes. Necesitan mantenerse en excelente estado de funcionamiento, pero a medida que pasa el tiempo, sufren fallos por externos manifestados en el ambiente. Por lo tanto, se resalta la necesidad de hacer un seguimiento efectivo de dichos sistemas. Los modelos neuronales son candidatos perfectos para realizar el reconocimiento de los daños físicos. En este caso, se compara el desempeño de tres redes neuronales artificiales, el perceptrón multicapa, la red neuronal densamente conectada y la red ResNet-50 en este problema de identificación. Lo que se pretende obtener de este método es la demostración práctica del uso de las redes neuronales para solucionar problemas reales

Experimental study of honeycomb SiCSi under highly concentrated solar flux: Evolution of its thermo-radiative properties

The material that is used in solar receivers is subjected to intense cyclic thermal stresses and extreme temperatures, which are directly dependent on the intermittence of the solar resource. These factors accelerate the ageing mechanisms and reduce the durability of the receivers because of a reduction of their thermal performance. This study presents guidelines to study the thermo-radiative properties of an absorber material that is subjected to a highly concentrated solar flux. The material was a square honeycomb SiCSi structure that is typically used in volumetric air receivers. Accelerated ageing tests were performed by means of crashing thermal treatments, in which the modulus and period of the incident flux and the boundary conditions of the material were varied. The reflectivity and absorptivity of the material were experimentally characterized before and after the thermal treatments. The measurements were performed using two different reflectometers, one monochromatic and one in the solar band; the latter can measure at ambient temperature or high temperature that is representative of the operational conditions (400-700 degrees C). However, only the solar band reflectometer working at high temperature was able to detect the evolution of the thermo-radiative properties of the material, which highlights the important role of the temperature and the wavelength. Furthermore, the thermal treatments in which the samples were water-cooled and in which the solar flux was medial more quickly accelerated the ageing mechanism of the material and reduced its absorptivity.The authors acknowledge the financial support of the research programme of the Universidad Carlos III de Madrid, 2015, which made this study possible through a mobility grant. Moreover, this work was supported by the French "Investments for the future" programme, which is managed by the National Agency for Research under contract ANR-10-LABX-22-01 by Labex SOLSTICE and by the Spanish government under the project ENE2012-34255

Development of a new method to estimate the incident solar flux on central receivers from deteriorated heliostats

This work proposes a new empirical direct methodology to estimate both the solar flux distribution and intensity on the surface of central receivers. In solar power tower plants with deteriorated heliostats, the numerical simulations to estimate the incident solar flux are not precise. Hence the thermal behaviour of the receivers cannot be determined. In those cases, direct measurement or semi-empirical methodologies are required to characterize the radiant power on the receiver. The new methodology proposed, named "Superposition method", consists in the hourly characterization of the reflected solar beam of each individual heliostat by means of a pyrheliometer, a passive screen, a flux sensor, a camera and digital image analysis. According to the aiming strategy used during receiver operation, each individual solar flux distribution and intensity can be gathered to obtain the total incident radiant power on the solar receiver. This non-real-time method has the advantage of reproducing any solar flux distribution on the receiver at present and past time

Anticipated Discrimination, Choices, and Performance: Experimental Evidence

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.This paper studies experimentally whether potential perceived discrimination affects decisions in a labor-market setting with different stereotypes. Participants are assigned to a seven-person group and randomly allocated a role as a firm or worker. In each group, there are five workers and two firms. The only information firms have about each worker is a self-selected avatar (male, female or neutral) representing a worker's gender. Each firm then decides which worker to hire. Female workers react to potential discrimination when they know the task is math-related, but not otherwise. Men choose similar avatar patterns regardless of the task. Men do perform at much higher levels in the math-related task, but there is no difference in performance in the emotion-recognition task, where there is a strong female stereotype.American University of SharjahUniversity of Exete

Diversity and abundance of rotifers during an annual cycle in the reservoir Valerio Trujano (Tepecoacuilco, Guerrero, Mexico)

We analyzed the diversity and density of monogonont rotifers collected from 10 sites, 5 in the littoral zone and 5 in the pelagic zone, during a 1-year period from March 2010 to April 2011 in the reservoir Valerio Trujano, altitude 820 m a.s.l. (Tepecoacuilco de Trujano, State of Guerrero, Mexico). We also measured physicochemical variables such as temperature, pH, hardness, nitrates, and phosphates. The rotifers were identified to species level and quantified using a Sedgwick-Rafter chamber. We found 62 species belonging to 28 genera and 19 families, representing 22% of total species reported for Mexico. The most abundant species were Brachionus caudatus, B. falcatus, Horaëlla thomassoni, Filinia longiseta, Conochilus dossuarius, and Keratella cochlearis. The highest rotifer densities were those of B. caudatus (around 300 ind. L-1) in June and July. The common phytoplankton genera were Pediastrum, Cosmarium, Closterium, Nitzschia, Suriella, Microcystis, Oscillatoria, and Merismopedia. The species diversity of Rotifera in the reservoir ranged from 1.3 to 3.2 in both the littoral and the pelagic regions. The saprobic index varied from 1.2 to 2 in the pelagic and 1.4 to 2.1 in the littoral region of the reservoir. Nutrient levels and indicator species (Brachionus and Trichocerca) showed that the reservoir, which was nitrogen rather than phosphorus limited, is eutrophic and moderately polluted by organic matter

Optical properties from extinction cross-section of single pollen particles under laboratory-controlled relative humidity

This work was supported by the Spanish Ministry of Science and Innovation through projects ELPIS (PID2020-12001-5RB-I00), by the Junta de Andalucía Excellence project ADAPNE (P20-00136), AEROPRE (P-18-RT-3820), FEDER Una manera de hacer Europa, EQC2019-006423-P, INTEGRATYON (PID2020-117825 GB-C21 and PID2020-117825 GB-C22), the European Union's Horizon 2020 research and innovation program through project ACTRIS. IMP (grant agreement No 871115), and ATMO-ACCESS (grant agreement No 101008004), and ACTRIS-España (RED2022-134824-E), FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades project DEM3TRIOS (A-RNM-430-UGR20) and by University of Granada Plan Propio through Excellence Research Unit Earth Science and Singular Laboratory AGORA (LS2022-1) programs and project Pre-GREENMITIGATION (PP2022.PP.34).A growing body of research suggests that pollen suspended in the atmosphere have a major environmental and climatic impact. However, our current knowledge of pollen is rather limited with respect to its extinction capacity, its optical properties and how these vary with atmospheric water content. Understanding their water absorption capacity can improve our understanding of their radiative effects and, thus, improve climate models. In this work, an electrodynamic Paul trap was coupled to a cavity ring down spectroscopy (CRDS) to directly measure the ring down time () of four individual types of pollen particles: Olea, Fraxinus, Populus and Salix exposed to changing relative humidity (RH). Resonant structures in values between ∼90 and 45 % RH indicated that pollen was wettable at high RHs. was used to calculate light extinction cross-section at 532 nm as a function of RH. Optical growth factor () was evaluated as the ratio between and From , the semi-empirical single hygroscopicity parameter () was found to be 0.038–0.058 for the four pollen types. Under controllable treatment of the water content and an adequate selection of complex refractive index , CRDS- data was fitted to theoretical from Mie theory. The reasonable agreement achieved allowed for gaining knowledge about the and how particle size shrugged during dehydration. As a result, a climate-lowering effect of Olea pollen particles, which contain a fraction of scattered aerosol, should be considered in the models.Spanish Ministry of Science and Innovation (PID2020-12001-5RB-I00)Junta de Andalucía Excellence: ADAPNE (P20-00136), AEROPRE (P-18-RT-3820), FEDER Una manera de hacer Europa, EQC2019-006423-P, INTEGRATYON (PID2020-117825GB-C21, PID2020-117825GB-C22)European Union's Horizon 2020 CTRIS.IMP 871115ATMO-ACCESS 101008004ACTRIS-España (RED2022-134824-E)FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades DEM3TRIOS (A-NM-430-UGR20)University of Granada LS2022-1, PP2022.PP.3

Agronomic biofortification with selenium improves the yield and nutraceutical quality in tomato under soilless conditions

Selenium (Se) is an essential element for humans. Its consumption comes from food of animal or vegetal origin; whose content varies widely depending on its availability in soil or anthropogenic sources. Biofortification improves food nutritional quality, and its consumption has a positive influence in human health. Thus, the objective of this research was to assess agricultural biofortification with Se in tomato fruit and its effects on yield, nutraceutical quality, and antioxidant capacity.  Five Se doses (0, 2, 4, 6, and 8 mg L-1) in the form of sodium selenite (Na2SeO3) were added in a nutritional solution in a hydroponic system.  The results obtained indicated that agricultural biofortification with Se applied in the nutritional solution improved yield, nutraceutical quality, and Se concentration in tomato fruit. The optimum Se dose that maximized yield and nutraceutical quality, as well as the recommended consumption concentration in tomato fruit in this study was 2 mg L-1 (Na2SeO4) because higher doses decreased yield and bioactive compound biosynthesis. Incorporating Se in the nutritional solution is an alternative to increase phytochemical compound biosynthesis in tomato fruit and yield with the possibility of improving public health with its consumption

A geodetic study of the 2003 January 22 Tecomán, Colima, Mexico earthquake

We use coseismic displacements and aftershock information from Global Positioning System (GPS) measurements at 27 sites in western Mexico and a 12-station local seismic network to determine the characteristics of the 2003 January 22 M_w = 7.2 subduction thrust earthquake near Tecomán, Colima, Mexico. Estimates of the earthquake moment, slip direction and best-fitting slip distribution are derived by optimizing the fit to the GPS displacements for a 3-D finite element mesh that simulates the study area. The calculated moment release is 9.1 × 10^(19) N m (M_w = 7.2) , with maximum slip of 2 m at a depth of 24 km and a maximum rupture depth of 35–40 km. The inversion indicates that coseismic rupture extended downdip from depths of 9 to 40 km along a 80 km along-strike region that is bounded by the edges of the Manzanillo Trough. The optimal solution is robust with respect to plausible changes in the subduction interface geometry and differing subsets of the data. A comparison of the cumulative post-seismic slip that can be inferred separately from earthquake aftershocks and GPS measurements within a year of the earthquake indicates that 95 per cent or more of the post-seismic deformation was aseismic. Near-term post-seismic measurements indicate that slip propagated downdip to areas of the subduction interface beneath the coastline within days following the earthquake, as also occurred after the nearby M_w = 8.0 Colima-Jalisco subduction earthquake in 1995. The similar behaviours and locations of the 1995/2003 earthquake sequence to two earthquakes in June of 1932 suggests that thrust earthquakes along the subduction interface northwest of the Manzanillo Trough may trigger earthquakes in the vicinity of the Manzanillo Trough; however, our modelling of Coulomb stress changes caused by the 1995 earthquake indicate that it induced only modest unclamping of the subduction interface in the vicinity of the Tecomán rupture. In addition, GPS measurements indicate that elastic shortening characterized areas onshore from the Tecomán rupture from mid-1997 up until the time of the rupture, consistent with progressively stronger clamping of the subduction interface during this period. This precludes any obvious triggering relationship with the 1995 earthquake. The apparent coincidence of the edge of both the 1932 and 1995/2003 rupture sequences with the edge of the Manzanillo Trough may indicate that the trough is a mechanical barrier to along-strike rupture propagation. This implies a limit to the area of potential slip and hence rupture magnitude during future large earthquakes in this region

Impact of manufacturing tolerances on axial flux permanent magnet machines with ironless rotor core: a statistical approach

Axial Flux Permanent Magnet (AFPM) machines with ironless rotors are an attractive and recently studied solution in low-speed applications, due to their potentially high power/weight ratio, high aspect ratio, and high efficiency. Nevertheless, these machines are prone to be affected by manufacturing tolerance during its fabrication process and consequently, the magnets may move freely inside the rotor structure. This work presents a statistical analysis of manufacturing tolerances of an AFPM machine with an ironless rotor, considering several magnet fault types. A computationally efficient superposition method is developed and implemented to obtain both the cogging torque and rated torque considering several tolerance combinations with acceptable accuracy. The results obtained from a statistical analysis of 10,000 designs of a two-stator one rotor tooth coil winding AFPM (TCW-AFPM) machine allowed us to identify the parameters with the most impact on relevant performance indicators and disclosed a substantial increase in cogging and ripple torque when unavoidable combined tolerances are present