117,457 research outputs found
Biogas in formato "alpino": fonti rinnovabili: quanta energia dal settore agricolo? Uno studio della FEM
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Relazioni tra prestazioni nella lettura e abilità di denominazione rapida (RAN): uno studio su bambini di scuola primaria
No full textDiversi studi hanno cercato di identificare quali sono gli indici predittivi delle capacità di lettura in campioni di bambini in età prescolare e scolare mettendo in luce la presenza di relazioni significative tra le prestazione nella lettura e alcune abilità cognitive. L’obiettivo di questa ricerca, condotta in Italia su un campione di 38 bambini di classe prima primaria, è quello di analizzare le reazioni tra le abilità di decodifica della lettura e la capacità di denominazione rapida automatizzata di figure, numeri e colori (RAN), uno degli indici predittivi più correlati alle abilità di decodifica. Ai partecipanti sono state somministrate una prova di lettura di parole e non parole e una prova di lettura sublessicale oltre a un test di RAN di numeri e colori. I risultati evidenziano la presenza di correlazioni forti tra alcune prove RAN e la performance di lettura, in particolare a livello di rapidità
Environmental, economic and energetic sustainability of anaerobic digestion plants in alpine regions
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DNA damage in Eelpout (Zoarces viviparus) from Göteborg harbor: a Comet assay evaluation
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Tribological and electrochemical performances of HVOF sprayed NbC-NiCr coatings
No full textA wide range of mechanical parts are protected against wear and corrosion by thermally sprayed WC- or Cr3C2-based hardmetals. However, little is known about the potential of other hardmetal coating formulations. Since promising results were obtained with bulk NbC-based hardmetal cutting tools, in this work we investigated NbC-based coatings, which have not been reported yet in the literature. NbC particles were homogeneously dispersed with volume fractions of 25 % and 40 % in a Ni-20wt.%Cr matrix by mechanical alloying, and the resulting powders were sprayed onto stainless steel substrates by the High-Velocity Oxygen Fuel (HVOF) process.Irrespective of the process parameters, the coatings exhibit low porosity (<1 vol%) and hardness values of about 900 HV0.3 (NbC-25NiCr) and 1000 HV0.3 (NbC-40NiCr). The composition with higher amount of NbC phase is less hard because its greater brittleness results in cracking during indentation.The sliding wear resistance of the NbC-based coatings, tested by ball-on-disc tribometry from room temperature up to 600 degrees C, is generally intermediate between that of WC-CoCr and Cr3C2-NiCr references, and it is usually comparable to that of TiC-NiCr, another type of alternative hardmetal coating, tested in our previous work. Though the NbC-NiCr coatings exhibited limited three-body abrasion resistance due to the occurrence of some brittle fracture together with ductile grooving, they offer a particularly interesting performance at 400 degrees C, with lower wear rates than Cr3C2-NiCr and TiC-NiCr.Additionally, the NbC-NiCr coatings tested in this work, especially the one with 40 vol% matrix phase, exhibit excellent corrosion resistance. Corrosion current densities (similar to 0.1 mu A/cm(2)) and passive current densities (<1 mu A/cm(2)), both obtained by electrochemical polarization tests, were lower than the corresponding values found for all reference coatings (WC-CoCr, Cr3C2-NiCr and TiC-NiCr),Thus, the NbC-NiCr coatings are promising for applications where a good balance between corrosion resistance and wear resistance over a range of temperatures is required
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