Search results for "NDT"

IMPLEMENTAZIONE DI TECNICHE DI TERMOGRAFIA ATTIVA IRNDT SU COMPOSITI GRP MEDIANTE LA DEPOSIZIONE DI IMPULSI TERMICI DI LUNGA DURATA

2011

Nel presente lavoro viene analizzata l’implementazione di tecniche attive di termografia ad infrarossi per analisi NDT su pannelli in composito. In particolare si propone l’uso di lampade alogene come sorgente di calore esterna, le quali richiedono tempi di accensione dell’ordine di diversi secondi al fine di depositare efficaci quantità di calore. Si discutono quindi le problematiche connesse all’implementazione di tecniche di Transient Thermography e di Lock-In Thermography in presenza di tempi lunghi di deposizione di calore. Viene implementata una tecnica di modulazione della deposizione di calore mediante treni di onde quadre di lunga durata (PMLT - Pulse Modulated Lock-In Thermography…

Computer-aided tool path generation for robotic Non-Destructive Inspection

2013

Compared to manual Non-Destructive Testing (NDT) for inspection of engineering components, automated robotic deployment of the same NDT techniques offers an increase in accuracy, precision and speed of inspection while reducing production time and associated labour costs. Traditionally, the robot tool path is either taught or programmed manually. Automation of NDT tool path generation, as presented in this paper, offers further significant time reduction, and an increase in the flexibility of inspection planning compared to manual robot teaching and programming. Moreover, such a solution helps to maintain a controlled probe orientation with respect to the scanned surface, and thus which can…

CFD prediction of flow, heat and mass transfer in woven spacer-filled channels for membrane processes

2021

Abstract Flow and heat or mass transfer in channels provided with woven spacers made up of mutually orthogonal filaments were studied by Computational Fluid Dynamics. The problem addressed was the combined effect of the parameters that characterize the process: pitch to height ratio P/H (2, 3 and 4), flow attack angle θ (0, 7, 15, 20, 30, 40 and 45°) and Reynolds number Re (from ~1 to ~4000). The Prandtl number was 4.33, representative of water at ~40°C, while the Schmidt number was 600, representative of NaCl solutions. Simulations were performed by the finite volume code Ansys CFX™ 18.1 using very fine grids of ~6 to ~14 million volumes. For Re > ~400, the SST turbulence model was used to…

Adaptive Type-2 Fuzzy Logic Control of Non-Linear Processes

2011

The main objective of this study is to provide a valid and effective approach for the design and development of an adaptive type-2 fuzzy controller (AT2FLC), based on the analysis of the nonlinear process dynamics and the use of an ANFIS technique for the optimization of the controller. The performance of the obtained AT2FLC, characterized by a few number of rules, is higher than the performance of a traditional type-2 fuzzy controller with a larger rule base. The proposed controller is particurarly suitable for the control of processes characterized by uncertainty and time varying parameters.

Dense Solid-Liquid Suspensions in Top-Covered Unbaffled Stirred Vessels

2011

In the present work solids suspension is investigated in an unbaffled tank stirred by a Rushton turbine and provided with a top-cover in order to avoid the formation of the well known central vortex. The data obtained are compared with those pertaining baffled stirred tanks via comparison with the well known Zwietering’s correlation. The dependence of Njs on particle concentration is found to be similar to that well established for baffled vessels, while, as a difference from the latter, Njs is found to decrease when liquid viscosity increases. Results also show that Njs is substantially independent of particle size, a feature that may advice the adoption of unbaffled tanks when large heavy…

CFD Simulation of Solid Liquid Suspensions in Baffled Stirred Vessels Below Complete Suspension Speed

2011

Suspension of solid particles into liquids within stirred vessels is a complex phenomenon encountered in several industrial applications. Most researchers have focused their attention on the assessment of the minimum impeller speed (Njs) able to guarantee the suspension of all particles. Actually, in a number of industrial cases an impeller speed N lower than Njs is chosen as typical operating condition (Oldshue, 1983) as the resulting energy savings well counterbalance the loss of active interfacial area. Therefore, the assessment of the amount of unsuspended particles at any given impeller speed represents the key to quantify the economical advantage/disadvantage of adopting an impeller s…

Città, diritti e pratiche di mutualismo: riflessioni a partire dalle istanze comunitarie ai tempi della pandemia

2022

During the pandemic crisis, the “community” practices of mutualism have characterized the urban space by operating in a subsidiary, if not a substitute, manner with respect to public institutions. Their actions have been political in the sense in which Hannah Arendt defined this concept. Starting from a reflection on vulnerabilities, taking a case study as the object, and dialoguing with Orsetta Giolo’s essay, The rights against the city. Urban space, subjectivity and the public sphere, published in 2021, the potential and limits of these practices will be analyzed, along with their relationship with established power, with respect to the renewed tension between rights and territoriality, w…

Wielandt's results for algebraic k-groups

2006

We analyze the relation between subnormality and nilpotence, the subnormal joint property, some criteria of subnormality, the norm and the Wielandt subgroup in the case of algebraic groups defined over an arbitrary field.

Varianti tonali al protocollo Arnoux-Sindt nel trattamento logopedia del granuloma laringeo posteriore

2009

Da Trump a Foucault. Postverità e parresia

2021

Vaccaro analyzes the philosophical-political status of the category "Post-Truth", from Arendt to Foucault, and opposes to it the concept of Parrhesia with its political radicality.