Search results for "weather"
showing 10 items of 360 documents
Influence of climatic variables on acute myocardial infarction hospital admissions
2009
BACKGROUND: Seasonal peaks in acute myocardial infarction (AMI) incidence have been widely reported. Weather has been postulated to be one of the elements at the basis of this association. The aim of our study was to determine the influence of seasonal variations and weather on AMI hospital admissions. METHODS: We correlated the daily number of AMI cases admitted to a western Sicily hospital over twelve years and weather conditions on a day-to-day basis. Information on temperature, humidity, wind force and direction, precipitation, sunny hours and atmospheric pressure was obtained from the local Birgi Air Force base. A total of 3918 consecutive patients were admitted with AMI over the perio…
Extracting science from Mössbauer spectroscopy on Mars
2003
[1] Deployment by the Mars Exploration Rovers of backscatter Mossbauer spectrometers offers an incredible opportunity to (1) elucidate the iron mineralogies of rocks, soils, and atmospheric dust and (2) gain insight into the physical event by which the mineralogy came into existence and consequently acquire information having potential for yielding ancient planetary history relevant to broad issues including the question of life. Determining the mineralogy is done by subjecting raw data to reduction algorithms and generating products known as Mossbauer parameters, which are highly characteristic. Mixed mineralogies are treated through deconvolution. Through being able to exploit Mossbauer m…
Search for magnetic minerals in Martian rocks: Overview of the Rock Abrasion Tool (RAT) magnet investigation on Spirit and Opportunity
2008
[1] The Rock Abrasion Tool (RAT) on board the Mars Exploration Rovers (MER) is a grinding tool designed to remove dust coatings and/or weathering rinds from rocks and expose fresh rock material. Four magnets of different strengths that are built into the structure of the RAT have been attracting substantial amounts of magnetic material during RAT activities from rocks throughout both rover missions. The RAT magnet experiment as performed on Spirit demonstrates the presence of a strongly ferrimagnetic phase in Gusev crater rocks, which based on Mossbauer and visible/near-infrared reflectance spectra is interpreted as magnetite. The amount of abraded rock material adhering to the magnets vari…
Weathering of Fe-bearing minerals under Martian conditions, investigated by Mössbauer spectroscopy
2004
Abstract The surface of Mars is covered by weathered material. Mars' rusty red colour in particular is commonly ascribed to ferric iron-bearing minerals. The planet's surface is generally iron rich. Mossbauer spectroscopy is a powerful tool for quantitative mineralogical analysis of Fe-bearing minerals. Consequently, the miniaturized Mossbauer spectrometer MIMOS II is part of the payload of NASA's twin Mars Exploration Rovers “Spirit” and “Opportunity”, and ESA's ill-fated Mars Express lander “Beagle 2”. Both Mars Exploration Rovers are currently conducting successful surface operations on Mars. In this paper, we give a brief insight into mission operations with respect to the reconstructio…
Effect of nano zinc oxide as UV stabilizer on the weathering performance of wood-polyethylene composite
2016
Abstract In this study, the effect of using nano-sized zinc oxide (ZnO) particles on the enhancement if the degradation resistance of wood-high density polyethylene (HDPE) composite was investigated through artificial weathering. Samples with different amounts of ZnO mixing ratio (0, 1, 2, and 4 wt%) were manufactured using an internal mixer followed by compression molding. The prepared samples were then exposed to the artificial weathering process in a QUV weatherometer. The weathering behavior of samples was characterized using tensile strength, contact angle analysis, colorimetry, ATR-FTIR spectroscopy and FE-SEM. The results indicated that the amount of surfaces crack, tensile strength …
Materials, Techniques, and Conservation of Historic Stained Glass “Grisailles”
2015
A grisaille is a brown-blackish paint applied onto the inner surface of stained glass to draw the contours and details of the figures and to produce the effect of shades and volumes. Grisailles were traditionally made of finely ground oxides of iron but also of copper, zinc, lead, or manganese mixed with a flux such as lead ground glass and a binder and fixed onto the flat glass by firing. The grisailles have typical layer thickness varying between 10 and 100 µm and are formed by a complex mixture of pigment particles, crystalline, and amorphous reaction compounds, aging, and weathering compounds. The high brilliance, collimation, energy selection, and monochromacity of the SR beam are idea…
Rheological, mechanical and morphological characterization of monopolymer blends made by virgin and photo-oxidized polypropylene
2021
In this work, monopolymer blends of virgin polypropylene and photo-oxidized polypropylene were prepare and characterized. The polypropylene samples were subjected to accelerated ageing to simulate the effects of outdoor exposure of polypropylene. After exposure, samples were pelletized and mixed with the same virgin polymer. The rheological, mechanical and morphological characterization was conducted on both the polymers and the blends. Both viscosity and mechanical properties decrease with increases in the content of recycled, photo-oxidized components and of the level of degradation of this component. In addition, the experimental data were compared with a model that takes into account bo…
Semiconducting properties of passive films and corrosion layers on weathering steel
2020
Abstract Anodic films were grown on Weathering Steel by potentiostatic polarization in slightly alkaline solution. The photoelectrochemical results reveal that they are n-type iron oxide with Eg = 2.0 eV. Rust layer grown by atmospheric corrosion are n-type semiconductors with a band gap higher than that estimated for the anodic film attributed to the formation of γ-lepidocrocite. The electrochemical impedance spectra allow to evidence that rust layers have a higher conductivity with respect to anodic films due to the presence of highly doped iron oxide layers. The use of Mott-Schottky theory to model the dependence of oxide capacitance as function of potential is critically discussed.
Inhibition of Cor-Ten steel corrosion by “green” extracts of Brassica campestris
2018
Abstract Extract of Brassica campestris was tested as potential corrosion inhibitor for Cor-Ten steel in NaCl and acidic solutions, simulating a marine and an urban-industrial environment, respectively. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were performed both in absence and in presence of the extract at room temperature. The surface chemical analysis was investigated by X-ray Photoemission Spectroscopy (XPS), before and after corrosion. Electrochemical results demonstrated that a very small concentration of Brassica campestris extracts can inhibit Cor-Ten corrosion in NaCl solution (inhibition efficiency of 80–84%) better than in acidic solutions. Su…
Accelerated weathering of PP based nanocomposites: Effect of the presence of maleic anhydryde grafted polypropylene
2013
Polymer nanocomposites are currently a topic of great interest. The increasing importance they are gaining also in the standpoint of industrial applications, is giving concerns regarding their environmental stability and, in general, their behaviour in outdoor applications, under direct solar irradiation. Papers available in the literature have highlighted the different influences of different nanosized fillers, in particular clay-based nanofillers; however, few data are available regarding other nanosized fillers. Furthermore, the research on polymer nanocomposites has clearly pointed out that the use of compatibilizers is required to improve the mechanical performance and the dispersion o…