100,470 research outputs found
Contenitori in Alluminio per Bevande: Processi Degenerativi del Rivestimento Interno e Rilascio di Metallo verso il Contenuto. Valutazioni Corrosionistiche e Tossicologiche
No full textCopper-based nanocluster composite silica films by rf-sputtering deposition
No full textPrescribed nanocluster composite glass features require the control of the cluster formation and growth, and therefore the definition of effective preparation protocols. In this work, copper-containing silica films were synthesized by sputtering co-deposition of copper and silica in a radiofrequency magnetron sputtering apparatus. The composite system was sequentially thermally-treated in different annealing environment (oxidizing and/or reducing). Characterization of samples along the various preparation steps was performed by Rutherford backscattering spectrometry, X-ray diffraction, and optical absorption spectroscopy. The copper behavior during the composite formation was complex: copper migration and aggregation depend critically on the annealing conditions, and quite different stable structures actually result, such as fcc Cu and/or monoclinic CuO nanoparticles
[Intrinsic ureteral endometriosis: description of a striking instance.]
No full textIntrinsic ureteral endometriosis is a very rare condition. A 41 y. o. woman with right hydroureteronephrosis and other aspecific symptoms came to our attention. The CT scan showed an ureteral obstacle causing the hydroureteronephrosis. She underwent ureterorenoscopy with biopsies of the lesion that did not result to be diriment. Suspecting a ureteral neoplasm, the patient then underwent ureteral resection and ureterocystoneostomy, and the extemporary histological examination resulted as endometriosis. The abdominal exploration showed a parametrial and a peritoneal growth - both compatible with the extemporary histological examination - that were also excised. The post-operative course was uneventful. The definitive hystological examination confirmed the perioperatory diagnosis. Intrinsic ureteral endometriosis is confirmed as a rare pathology with an indefinite clinical presentation; its typical presentation, namely cyclic hematuria, seems to be an anecdotal feature. Therefore the diagnostics of intrinsic ureteral endometriosis is still difficult even despite such a striking presentation
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Forecasting sugarcane yields using agro-climatic indicators and Canegro model : a case study in the main production region in Brazil
No full textTimely crop yield forecasts at regional and national level are crucial to manage trade and industry planning and to mitigate price speculations. Sugarcane is responsible for 70% of global sugar supplies, thus making yield forecasts essential to regulate the global commodity market. In this study, a sugarcane forecasting system was developed and successfully applied to São Paulo State, the largest cane producer in Brazil. The system is based on multiple linear regressions relating agro-climatic indicators and outputs of the sugarcane model Canegro to historical yield records. The resulting equations are then used to forecast the yield of the current season using 10-day period updated values of indicators and model outputs as the season progresses. We quantified the reliability of the forecasting system in different stages of the sugarcane cycle by performing cross-validations using the 2000–2013 time series of official stalk yields. Agro-climatic indicators alone explained from 38% of inter-annual yield variability (at State level) during the boom growth phase (i.e., January–April) to 73% during the second half of the harvesting period (i.e., September–October). When Canegro outputs were added to the regressor set, the variability explained increased to 63% for the boom growth phase and 90% after mid harvesting, with the best performances achieved while approaching the end of the harvesting window (i.e. at the beginning of October, SDEP = 0.8 t ha− 1, R2cv = 0.93). It is concluded that the overall performances of the system are satisfactory, considering that it was the first attempt based on information exclusively retrieved from the literature. Further improvements to operationalize the system could be possibly achieved by the use of more accurate inputs possibly supplied by the collaboration with local authorities
On the synthesis and thermal stability of RuN, an uncommon nitride
No full textRuthenium nitride (RuN) is a compound that under ambient conditions presents positive enthalpy of formation. Recently, we synthesized RuN thin films in the zinc-blende structure by radiofrequency magnetron sputtering. The effect of changing the synthesis parameters was investigated in detail, but many questions remained open. Now we are able to disclose relevant aspects of the effect of the direct energy deposition by particles striking the substrates during the film growth. This has been accomplished by modifying the configuration of the source magnets from the unbalanced to the balanced one. The thermal stability of the synthesized compound has been investigated by annealing either in ultra-high-vacuum (UHV) or in air. In UHV the nitride was stable up to about 230 °C; at higher temperatures there was a marked loss of nitrogen and formation of metallic hexagonal close-packed ruthenium was observed. In air the stability limit was close to 200 °C; at higher temperatures we observed a slow nitrogen loss and an increase of oxygen incorporation. This behavior is due to the occurrence of chemical reactions leading to the formation of a surface layer containing oxynitride, hydroxide and oxide species. At 350 °C ruthenium oxide and metallic hexagonal close-packed ruthenium are present below the surface
Small angle scattering of Ag-1 wt.% Mg alloys internally oxidized at high temperatures: a model of interacting spherical clusters
No full textStrong interference effects in the X-ray small angle scattering (SAXS) intensity vs. scattering-angle plot are shown to appear in foil specimens of a relatively concentrated Ag-Mg alloy (1 wt.% Mg corresponding to 4.3 at.% Mg) treated in air under two very different high temperature conditions. Such interference effects are ascribed to MgOv clusters formed during an internal oxidation process and are quantitatively evaluated applying a special theoretical approach based on a model of interacting spherical particles. It is found that, in the sample oxidised at 1023 K for 2 min, particles with a surface-weighted average diameter of 1.4 nm are present and occupy 5.4% of the sample volume. In the sample oxidised at 1123 K for 6 h, the particles are larger (3.3 nm) and represent a 3.8% volume fraction. The clusters formed at lower temperatures for a few minutes are much richer in oxygen (v=1.6) than those formed at higher temperatures for some hours, which are composed of stoichiometric (v=1) magnesium oxide
Copper-based nanocluster composite silica films by rf-sputtering deposition
No full textPrescribed nanocluster composite glass features require the control of the cluster formation and growth, and therefore the definition of effective preparation protocols. In this work, copper-containing silica films were synthesized by sputtering co-deposition of copper and silica in a radiofrequency magnetron sputtering apparatus. The composite system was sequentially thermally-treated in different annealing environment (oxidizing and/or reducing). Characterization of samples along the various preparation steps was performed by Rutherford backscattering spectrometry, X-ray diffraction, and optical absorption spectroscopy. The copper behavior during the composite formation was complex: copper migration and aggregation depend critically on the annealing conditions, and quite different stable structures actually result, such as fcc Cu and/or monoclinic CuO nanoparticles
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