Search results for "init"
showing 10 items of 6629 documents
Investigations on the linear friction welding process through numerical simulations and experiments
2012
Abstract Linear Friction Welding (LFW) is a solid-state joining process applied to non-axisymmetric components. LFW involves joining of materials through the relative motion of two components undergoing an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and eventually bonding conditions. In the paper the authors present a designed and assembled laboratory fixture for LFW operations and the results of an experimental and numerical campaign aimed to weld steel parts. The dedicated fixture permitted to highlight the effect of the most important process parameters. Process conditions allowing ef…
The global cracking laws for a finite-element model of no-tension material
1992
Abstract For perfect no-tension materials (NRT) the validity of the local stability postulate of Drucker, well known in plasticity, has been assumed so far and utilized to derive the local cracking laws, which relate cracking strain states and stress states to each other. On this base a finite-element (FE) model with suitable constitutive behaviour for the single FE is presented. Classical FE approaches enforce the cracking laws at the Gauss points of the FEs. In this work it is shown that taking into account cracking strains, suitably modelled, over the whole domain of the FE and making use of an energy approach lead to general cracking laws describing the constitutive behaviour of the who…
Comparison of 2D versus 3D diffusion analysis at Nanowire Electrodes: Finite element analysis and experimental study
2021
In electroanalysis, finite element simulations of electrochemical processes occurring at electrodes are used to provide key insight into experimental design in relation to diffusion profiles and expected currents. The diffusion domain approach (DDA) offers a means of reducing a three dimensional design to two dimensions to ease computational demands. However, the DDA approach can be limited when basic assumptions, for example that all electrodes in an array are equivalent, are incorrect. Consequently, to get a more realistic view of molecular diffusion to nanoelectrodes, it is necessary to undertake simulations in 3D. In this work, two and three dimensional models of electrodes comprising o…
Mechanism of aluminium incorporation into C–S–H from ab initio calculations
2014
Blended cements have great potential to reduce the CO2 footprint due to cement production. C(alcium)–S(ilicate)–H(ydrate) in these novel materials is known to incorporate a considerable amount of Al. We have for the first time applied large-scale first principles calculations to address the mechanism of Al incorporation into low C/S ratio C–S–H. In agreement with state-of-the-art NMR information, our calculations show that Al substitutes Si in bridging tetrahedra only, and that substitutions in pairing tetrahedra are strongly disfavoured in a wide range of conditions. In broad terms, the energy penalty for having an Al atom in a pairing position is of about 20 kcal mol−1. Al in bridging tet…
Effect of different aqueous solutions of pure salts and salt mixtures in reverse electrodialysis systems for closed-loop applications
2018
Abstract Reverse Electrodialysis (RED) in a closed-loop arrangement is a viable way to convert low-grade heat into electric power. The present work experimentally investigates the use of pure salt- and equimolar two salts-water solutions as feeds in a lab-scale RED unit. RED performances were analysed in terms of Open Circuit Voltage (OCV), stack resistance and corrected power density. The pure salts and the mixtures employed were chosen via a computational analysis. Effect of feed solution velocity and concentration was investigated. Results concerning the pure salt-water experiments show that NH4Cl is the most performing salt in the concentration range probed, while higher power density v…
Thermal-hydraulic behaviour of the DEMO divertor plasma facing components cooling circuit
2017
Abstract Within the framework of the Work Package DIV 1 – “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. A comparative evaluation study has been performed considering three different options for the cooling circuit layout of the divertor Plasma Facing Components (PFCs). The potential improvement in the thermal-hydraulic performance of the cooling system, to be achieved by modifying cooling circuit layout, has been also assessed and discussed in terms of optimization strategy. The research acti…
Tracking Changes in Frontal Lobe Hemodynamic Response in Individual Adults With Developmental Language Disorder Following HD tDCS Enhanced Phonologic…
2020
Background: Current research suggests a neurobiological marker of developmental language disorder (DLD) in adolescents and young adults may be an atypical neural profile coupled with behavioral performance that overlaps with that of normal controls. Although many imaging techniques are not suitable for the study of speech and language processing in DLD populations, fNIRS may be a viable option. In this study we asked if fNIRS can be used to identify atypical cortical activation patterns in individual adults with DLD and track potential changes in cortical activation patterns following a phonological working memory training protocol enhanced with anodal HD tDCS stimulation to the presuppleme…
Espressione scritta per lo sviluppo della creatività e della capacità critica in Università
2018
La scoperta della scrittura ha svincolato il pensiero dal contesto e lo ha reso capace di interpretare i messaggi linguistici a partire solamente dalla parola e dalle loro connessioni logiche, ragionamento logico che permette argomentazioni più ampie, categorizzazioni più sistematiche, codificazioni sempre più precise. L’attività di scrittura favorisce l’acquisizione di schemi cognitivi utili alla strutturazione logica del pensiero, promuove abilità di pianificazione e di organizzazione delle proprie idee in modo rigoroso, contribuisce allo sviluppo di capacità espressive formali. I saggi sono stati corretti usando “la Guida per la correzione dei temi” di Calonghi e Boncori (2006). Dalla co…
From Mannose to Small Amphiphilic Polyol: Perfect Linearity Leads To Spontaneous Aggregation
2016
Terminally unsaturated and diastereochemically pure polyol derived from d-mannose shows spontaneous aggregation behavior in water solution. In order to study and clarify this unforeseen phenomenon, a conformational study based on NMR spectroscopy combined with ab initio structure analysis using the COSMO-solvation model was pursued. The results, together with X-ray diffraction studies, suggest a low energy linear conformation for this particular substrate both in solid states and in solution. For such small-sized acyclic carbohydrate derivatives, the linear conformation appears to be a key prerequisite for the unusual molecular self-assembly reported herein. peerReviewed
Pressure-Driven Isostructural Phase Transition in InNbO4: In Situ Experimental and Theoretical Investigations
2017
[EN] The high-pressure behavior of technologically important visible-light photocatalytic semiconductor In.NbO4, adopting a monoclinic wolframite-type structure at ambient conditions, was investigated using synchrotron-based X-ray diffraction, Raman spectroscopic measurements, and first-principles calculations. The experimental results indicate the occurrence of a pressure-induced isostructural phase transition in the studied compound beyond 10.8 GPa. The large volume collapse associated with the phase transition and the coexistence of two phases observed over a wide range of pressure shows the nature of transition to be first-order. There is an increase in the oxygen anion coordination num…