Uso da radiação solar pelo milho sob diferentes preparos do solo, espaçamento e disponibilidade hídrica

O objetivo deste trabalho foi avaliar a eficiência de interceptação e de uso da radiação fotossinteticamente ativa (RFA) pela cultura do milho em diferentes sistemas de manejo do solo, arranjos de plantas e disponibilidade hídrica. O milho foi cultivado em plantio direto e preparo convencional, na combinação com duas disponibilidades hídricas (irrigado e sequeiro) e espaçamentos de 40 e 80 cm entre fileiras de plantas. Em cada tratamento, foram instalados sensores para medida da RFA transmitida pela cultura, na superfície do solo, ao passo que a RFA incidente foi medida acima da cultura. A redução da distância entre fileiras aumentou a eficiência de interceptação em todos os tratamentos. Sob plantio direto, a cultura apresentou maior eficiência de interceptação em relação ao preparo convencional. O deficit hídrico diminuiu a eficiência de interceptação devido ao enrolamento foliar, e esse efeito foi mais pronunciado em preparo convencional, em ambos espaçamentos estudados. Embora a eficiência de interceptação tenha sido maior no espaçamento de 40 cm, a eficiência de uso não diferiu entre espaçamentos, mas diminuiu em condições de deficit hídrico.

Solar radiation use efficiency by soybean under field conditions in the Amazon region

The objective of this work was to evaluate the efficiency of soybean (Glycine max) in intercepting and using solar radiation under natural field conditions, in the Amazon region, Brazil. The meteorological data and the values of soybean growth and leaf area were obtained from an agrometeorological experiment carried out in Paragominas, Pará state, during 2007 and 2008. The radiation use efficiency (RUE) was obtained from the ratio between the above-ground biomass production and the intercepted photosynthetically active radiation (PAR) accumulated to 99 and 95 days after sowing, in 2007 and 2008, respectively. Climatic conditions during the experiment were very distinct, with reduction in rainfall in 2007, which began during the soybean mid-cycle, due to the El Niño phenomenon. An important reduction in the leaf area index and biomass production was observed during 2007. Under natural field conditions in the Amazon region, the values of RUE were 1.46 and 1.99 g MJ-1 PAR in the 2007 and 2008 experiments, respectively. The probable reason for the differences found between these years might be associated to the water restriction in 2007 coupled with the higher air temperature and vapor pressure deficit, and also to the increase in the fraction of diffuse radiation that reached the land surface in 2008.

Forecasting the Earth"s radiation belts and modeling solar energetic particle events: Recent results from SPACECAST

High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7-8 October 2012, and the period following a fast solar wind stream on 25-26 October 2012 to within a factor of 5 or so. At lower energies of 10- a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.

Intercepted solar radiation by maize crops subjected to different tillage systems and water availability levels

The objective of this work was to evaluate changes in the photosynthetic photon flux density (PPFD) interception efficiency and PPFD extinction coefficient for maize crop subjected to different soil tillage systems and water availability levels. Crops were subjected to no-tillage and conventional tillage systems combined with full irrigation and non-irrigation treatments. Continuous measurements of transmitted PPFD on the soil surface and incoming PPFD over the canopy were taken throughout the crop cycle. Leaf area index and soil water potential were also measured during the whole period. Considering a mean value over the maize cycle, intercepted PPFD was higher in the conventional tillage than in the no-tillage system. During the initial stages of plants, intercepted PPFD in the conventional tillage was double the PPFD interception in the no-tillage treatment. However, those differences were reduced up to the maximum leaf area index, close to tasseling stage. The lowest interception of PPFD occurred in the conventional tillage during the reproductive period, as leaf senescence progressed. Over the entire crop cycle, the interception of PPFD by the non-irrigated plants was about 20% lower than by the irrigated plants. The no-tillage system reduced the extinction coefficient for PPFD, which may have allowed a higher penetration of solar radiation into the canopy

A numeric model to simulate solar individual ultraviolet exposure.

Exposure to solar ultraviolet (UV) light is the main causative factor for skin cancer. UV exposure depends on environmental and individual factors. Individual exposure data remain scarce and development of alternative assessment methods is greatly needed. We developed a model simulating human exposure to solar UV. The model predicts the dose and distribution of UV exposure received on the basis of ground irradiation and morphological data. Standard 3D computer graphics techniques were adapted to develop a rendering engine that estimates the solar exposure of a virtual manikin depicted as a triangle mesh surface. The amount of solar energy received by each triangle was calculated, taking into account reflected, direct and diffuse radiation, and shading from other body parts. Dosimetric measurements (n = 54) were conducted in field conditions using a foam manikin as surrogate for an exposed individual. Dosimetric results were compared to the model predictions. The model predicted exposure to solar UV adequately. The symmetric mean absolute percentage error was 13%. Half of the predictions were within 17% range of the measurements. This model provides a tool to assess outdoor occupational and recreational UV exposures, without necessitating time-consuming individual dosimetry, with numerous potential uses in skin cancer prevention and research.

Centre d’Assistència Primària, Aparcament i Urbanització exterior al solar d'equipament Can Bruguera, Vilassar de Dalt

Award-winning

Forecasting the Earth"s radiation belts and modeling solar energetic particle events: Recent results from SPACECAST

High-energy charged particles in the van Allen radiation belts and in solar energetic particle events can damage satellites on orbit leading to malfunctions and loss of satellite service. Here we describe some recent results from the SPACECAST project on modelling and forecasting the radiation belts, and modelling solar energetic particle events. We describe the SPACECAST forecasting system that uses physical models that include wave-particle interactions to forecast the electron radiation belts up to 3 h ahead. We show that the forecasts were able to reproduce the >2 MeV electron flux at GOES 13 during the moderate storm of 7-8 October 2012, and the period following a fast solar wind stream on 25-26 October 2012 to within a factor of 5 or so. At lower energies of 10- a few 100 keV we show that the electron flux at geostationary orbit depends sensitively on the high-energy tail of the source distribution near 10 RE on the nightside of the Earth, and that the source is best represented by a kappa distribution. We present a new model of whistler mode chorus determined from multiple satellite measurements which shows that the effects of wave-particle interactions beyond geostationary orbit are likely to be very significant. We also present radial diffusion coefficients calculated from satellite data at geostationary orbit which vary with Kp by over four orders of magnitude. We describe a new automated method to determine the position at the shock that is magnetically connected to the Earth for modelling solar energetic particle events and which takes into account entropy, and predict the form of the mean free path in the foreshock, and particle injection efficiency at the shock from analytical theory which can be tested in simulations.

Fachada solar como pieza singular de arquitectura sostenible

Articulo sobre la importancia de las energias renovables y su integración arquitectónica en el camino hacia una arquitectura sostenible. Descripción y evaluación del proyecto Fachada Solar SCHOTT Iberica.

Documentació arqueològica del Fortí del Rei (S. XVIII): intervenció en el solar núm. 54 de l'Avinguda de la Reina Maria Cristina de Tarragona

L'exercici de l'arqueologia urbana a Tarragona ha permès la documentació de restes arquitectòniques del fortí del Rei, bastit en el context de la Guerra de Successió. L'element més significatiu és la documentació d'una galeria i/o camí protegit que connectava aquest fortí amb el de l'Oliva.

Estimating the contribution of occupational solar ultraviolet exposure to skin cancer

BACKGROUND: Exposure to solar ultraviolet (UV) light is the main causative factor for skin cancer. Outdoor workers are at particular risk because they spend long working hours outside, may have little shade available and be bound to take their lunch at their workplace. Despite epidemiological evidence of a doubling in risk of squamous cell carcinoma in outdoor workers, the recognition of skin cancer as an occupational disease remains scarce. OBJECTIVE: To assess occupational solar UV doses and its contribution to skin cancer risk. METHODS: A numerical model (SimUVEx) was used to assess occupational and lunch break exposures, characterize exposure patterns and anatomical distribution. Risk of squamous cell carcinoma (SCC) was estimated from an existing epidemiological model. RESULTS: Horizontal body locations received 2.0-2.5 times more UV than vertical locations. Dose associated to lunch outdoor every day was similar to outdoor work one day per week but only half of a seasonal worker. Outdoor workers are associated with an increased risk of SCC but also of frequent acute episodes. CONCLUSION: Occupational solar exposure contributes largely to the overall lifetime UV dose, resulting in an excess risk of SCC. The magnitude of the estimated excess in risk supports the recognition of SCC as an occupational disease.

Análise físico-química, microbiológica e sensorial de frutos de manga submetidos à desidratação osmótico-solar

Polpas de mangas foram submetidas a um processo de secagem solar após pré-tratamento osmótico, com o intuito de obter-se produtos de umidade intermediária. Foram testados quatro pré-tratamentos osmóticos, ou seja, imersão em xaropes de sacarose com 45º Brix, 55º Brix, 65º Brix e imersão seqüenciada em xaropes de 45; 55 e 65º Brix. O processamento envolveu os seguintes passos: desidratação osmótica nas soluções de sacarose adicionadas de substâncias conservantes e secagem solar. Após a secagem, os tratamentos com 45 e 65º Brix foram selecionados através de análise sensorial para avaliação da estabilidade durante 180 dias de armazenamento à temperatura ambiente (28º C). Durante todo o processamento e/ou após a obtenção dos produtos finais, três tipos de avaliações foram realizadas: determinações físico-químicas (atividade de água, pH, acidez total, vitamina C, sólidos solúveis, umidade, açúcar total e açúcares redutores), análises microbiológicas e testes sensoriais. De acordo com os resultados obtidos, os dois produtos apresentaram boa estabilidade no que se refere às propriedades microbiológicas e sensoriais durante o armazenamento.

Projecte per la instal·lació de calefacció i A.C.S. solar en una vivenda unifamiliar

Es té una vivenda unifamiliar, de nova construcció, en la que s'ha elaborat un projecte per proporcionar-li un sistema de calefacció, i aprofitant l'energia solar produir ACS. S'han calculat les necessitats tèrmiques de la vivenda considerant que s'ha construit l'envolvent tèrmic de la vivenda segons CTE. S'han estudiat els possibles sistemes de calefacció i s'ha escollit el de radiadors d'aigua calenta amb distribució bitubular i caldera de gasoil. S'han determinat les necessitats d'ACS i s'ha projectat la instal·lació solar amb captadors de tubs de buit i recolzament auxiliar de la pròpia caldera de calefacció. Les instal·lacions s'han projectat complint els requisits de la normativa d'obligat compliment.