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We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was to open discussions related to the degradation observed in Sun-observing instruments exposed to the effects of the space environment. This article summarizes the various lessons learned and offers recommendations to reduce or correct expected degradation with the goal of increasing the useful lifespan of future and ongoing space missions.

We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was to open discussions related to the degradation observed in Sun-observing instruments exposed to the effects of the space environment. This article summarizes the various lessons learned and offers recommendations to reduce or correct expected degradation with the goal of increasing the useful lifespan of future and ongoing space missions.

During approximately 80% of its growing season, lowland flooded irrigated rice ecosystems in southern Brazil are kept within a 5–10-cm water layer. These anaerobic conditions have an influence on the partitioning of the energy and water balance components. Furthermore, this cropping system differs substantially from any other upland nonirrigated or irrigated crop ecosystems. In this study, daily, seasonal, and annual dynamics of the energy and water balance components were analyzed over a paddy rice farm in a subtropical location in southern Brazil using eddy covariance measurements. In this region, rice is grown once a year in low wetlands while the ground is kept fallow during the remaining of the year. Results show that the energy budget residual corresponded to up to 20% of the net radiation during the rice-growing season and around 10% for the remainder of the year (fallow). The energy and water balance analysis also showed that because of the high water table in the region, soil was near saturation most of the time, and latent heat flux dominated over sensible heat flux by up to one order of magnitude in some cases. The estimate of evapotranspiration ET using the crop coefficient multiplied by the reference evapotranspirationK c ETₒ and the Penman–Monteith equation ETPM, describing the canopy resistance through leaf area index (LAI) obtained by remote sensing, represent well the measured evapotranspiration, mainly in the fallow periods. Therefore, using a specific crop parameter like LAI and crop height can be an easy and interesting alternative to estimate ET in vegetated lowland areas.

Bismuth ferrite, whose formula is BiFeO 3 (BFO), is widely studied for its photovoltaic and photocatalytic properties. In this study, samples of this material were synthesized using the microwave-assisted hydrothermal method with the aim of measuring its ability to discolor contaminants present in water in previously formulated concentrations through photocatalysis. Photocatalysis is a process with great potential for applicability in the decontamination of effluents. The analysis process used a 1:1 molar ratio of bismuth nitrate to iron nitrate, with the addition of potassium hydroxide to the aqueous solution. Two samples were synthesized at different temperatures, specifically 140 °C and 160 °C. An X-ray diffraction analysis revealed that the synthesized samples were in an amorphous state. Photocatalytic tests were carried out to evaluate the ability of these materials to decolorize rhodamine B present in water in a previously known proportion. A sample synthesized at 140 °C successfully decolorized the solution within 60 min, providing its potential application in photocatalytic processes for decolorization of organic substances from wastewater. In turn, a sample synthesized at 160 °C discolored or contaminated in a slightly longer time. The samples were also subjected to a temperature of 750 ºC until crystallinity was reached. However, photocatalytic tests with crystalline samples performed less well than amorphous samples.

UV-screening by terrestrial plants is a crucial trait since colonization of terrestrial environments has started. In general, it is enabled by phenolic substances. Especially for grasses it remains unclear why plants grown under the absence of UV-B-radiation exhibit nonetheless a high UV-B-screening potential. But this may be explained by the UV-screening effect of the silicon double layer. It was shown for seedlings of soybeans (Glycine max L.) and wheat (Triticum aestivum L.) that enhanced silicon supply reduces stress induced by UV-radiation. Even more important is a direct correlation between silicon content in the epidermis near area (intercellular spaces) and the absorption of UV-radiation in this area shown in other papers. The silicon double layer may act like a glass layer and decreases the transmission of UV-radiation at the epidermis near area. In summary, the absorbance/reflection of ultraviolet radiation is dependent on the characteristics of the epidermis near area of leaves, particularly the occurrence (qualitatively and quantitatively) of phenolic substances and/or a silicon double layer in this area. Consequently, UV-screening by plant silicon double layer should get more attention in future research with emphasis on effects of UV-radiation on plant physiology.

Purpose Although silicon is not an essential element in sensu stricto for plant growth, it affects plant stress resistance and may affect the composition of cell wall compounds, especially of grasses. Where silicon availability alters the stoichiometry of macro nutrients in grasses, data on the interaction with calcium and micro nutrients are rare and hence are focussed on in this study. Methods The effect of silicon availability on calcium and micro nutrient content of the leaf blades of common reed, Phragmites australis , were assessed in a pot experiment with three levels of silicon supply. Results Calcium and micro nutrient concentrations and stoichiometry in leaf blades is altered by changing silicon availability during plant growth. In addition, Scanning Electron Microscopy (SEM) reveals that elevated silicon supply promotes silica deposition and changes the element content of micro and macro nutrients in the near epidermis tissue of P. australis leaves. Conclusion Silicon availability has a major impact on calcium and micro nutrient content and stoichiometry in grasses. This in turn may considerably affect the nutrient cycling in grass dominated ecosystems.

Systems with a ferroelectric to paraelectric transition in the vicinity of room temperature are useful for devices. Adjusting the ferroelectric transition temperature ( T c ) is traditionally accomplished by chemical substitution—as in Ba x Sr 1- x TiO 3 , the material widely investigated for microwave devices in which the dielectric constant ( ε r ) at GHz frequencies is tuned by applying a quasi-static electric field 1 , 2 . Heterogeneity associated with chemical substitution in such films, however, can broaden this phase transition by hundreds of degrees 3 , which is detrimental to tunability and microwave device performance. An alternative way to adjust T c in ferroelectric films is strain 4 , 5 , 6 , 7 , 8 . Here we show that epitaxial strain from a newly developed substrate can be harnessed to increase T c by hundreds of degrees and produce room-temperature ferroelectricity in strontium titanate, a material that is not normally ferroelectric at any temperature. This strain-induced enhancement in T c is the largest ever reported. Spatially resolved images of the local polarization state reveal a uniformity that far exceeds films tailored by chemical substitution. The high ε r at room temperature in these films (nearly 7,000 at 10 GHz) and its sharp dependence on electric field are promising for device applications 1 , 2 .

The very decorative heartwood of Brosimum guianense is internationally well known. Snakewood, as it is colloquially known, is represented in wood databases (e.g. the DELTA or InsideWood) as well as in lists of commercial timbers of many timber trading companies. The very decorative heartwood is hardly available and gains prices of up to 25 [Euro Sign]/kg in form of half stems. In the present study, the chemical composition and especially the subcellular cell structure was analysed by means of UV microspectrophotometry to explain the high natural durability and some extraordinary physical properties in addition to the anatomical composition. The heartwood consists of approximately 39% lignin, 54% carbohydrates and 0.4% lipophilic compounds of unspecified origin. The fibres are very thick-walled. Numerous sclerotic tyloses and organic deposits are present in the vessel. The extractives in high content are also components of parenchyma cells as well as in tyloses, respectively. These detected phenolic extractives, partly of flavonoid character, are also part of the cell wall. Calcium oxalate crystals are deposited in the upright and square cells of rays and sporadically in axial parenchyma cells. These facts are reasons for the famous natural durability of Snakewood. The sapwood density ranges from 1.1 to 1.4 g/cm³ for heartwood (12% mc). The compression strength (119 N/mm²), the bending strength (241 N/mm²), the modulus of elasticity (23,200 N/mm²) and the hardness (196 N/mm²) indicate exceedingly high elastomechanical properties.

Geralmente, o enterro do ser humano pode contribuir para a poluição da água subterrânea, quando do contato com o lixiviado gerado a partir da decomposição dos corpos na zona não saturada do subsolo. O monitoramento desse tipo de atividade foi realizado neste trabalho, que teve como objetivo a determinação da qualidade da água subterrânea em zona ocupada por cemitério. Para isto, utilizou-se a técnica de Espectrometria de Fluorescência de Raios-X por Energia Dispersiva (EDXRF) para a caracterização química da água subterrânea. Foram construídos cinco poços de monitoramento, de acordo com os padrões brasileiros. Foi estimada a flutuação do lençol freático, a superfície potenciométrica e as concentrações dos elementos cálcio, cobre, ferro, fósforo e silício. O Nível da água apresentou-se bastante superficial, variando entre 0,48 a 0,95 m no período seco. A concentração de cálcio variou entre 4,65 a 17,85 mg L-1, cobre entre 0,02 ± 0,29 mg L-1, ferro variou de 0,57 a 15,96 mg L-1, fósforo entre 12 a 13,98 mg L-1, e por último o silício, variando entre 35,55 a 79,12 mg L-1. Conclui-se que o uso da técnica de EDXRF demonstrou ser rápida e eficiente para quantificação de alguns constituintes em águas subterrâneas coletadas em poços de monitoramento sob a influência de cemitério em terreno silto-argiloso.