0000000000948488
AUTHOR
G. Vella
showing 47 related works from this author
XPL, a Presentation Language based on User Interface Design Pattern
2007
The great diversity of presentations in software applications deals with fulfillment of various type of graphic interface constructions related to different programming Languages. Moreover, in the Internet era html pages play a main role because of the increasing complexity of Web applications. In Software Engineering, the use of design patterns is proven remarkable for the design and reuse of software components. Visual Design. Patterns (ViDP) are useful to define interaction schemas between. user and computer. By the some token, visual design. patterns are useful to incorporate common interfaces of interaction, schemas between user and computer. This paper describes the eXtensible Present…
An Agile methodology for Manufacturing Control Systems development
2007
Robotized manufacturing cells are required more and more often to process high variety of short life-cycle product. This increases the need for methods and techniques for easy reconfiguration of software programs running in Programmable Logic Controllers (PLC), i.e., devices able to control manufacturing systems. PLCs run embedded code characterized by a procedural nature that does not make it quite reconfigurable. In this paper we propose an AGIle COntrol System Development (AGICOSD) methodology that uses various practices of Agile software development methodologies and the Design By Contract (DBC) practice for modeling and programming manufacturing control systems. In this context we prop…
The eXtensible Dynamic Presentation Manager for content adaptation
2008
Human Computer Interaction studies deals with systems and tools that are able to improve user experience during interaction with computer. For this purpose, modern web application are expected to supply multimodal and multi-channel access, adaptivity and transcoding features. We will present in this work the eXtensible Dynamic Presentation Manager (XDPM) which is a set of innovative tools that support the eXtensible Presentation Language (XPL) in the adaptation of contents to different working contexts. The adaptation is performed according to the delivery context information which have been formalized by means of a profiler system. A profile holds information about the specific access devi…
Modelling and Simulation of Gas–liquid Hydrodynamics in a Rectangular Air-lift Reactor
2013
Abstract Computational Fluid Dynamics is a quite well established tool for carrying out realistic simulations of process apparatuses. However, as a difference from single phase systems, for multiphase systems the development of CFD models is still in progress. Among the two-phase systems, gas–liquid systems are characterised by an additional complexity level, related to the fact that bubble sizes are not known in advance, being rather the result of formation and breakage-coalescence dynamics and therefore of complex phenomena related to flow dynamics and interfacial effects. In the present work, Euler–Euler Reynolds-averaged flow simulations of an air-lift reactor are reported. All bubbles …
The hydraulic behaviour of the simulacrum of the Dome Liner of an ITER divertor cassette
2007
The hydraulic behaviour of the simulacrum of the Inner Vertical Target of an ITER divertor cassette
2007
Characterization of pressure retarded osmosis lab-scale systems
2016
Power generation from salinity gradient is a viable alternative to produce energy from renewable sources. Pressure Retarded Osmosis (PRO) is one of the technologies proposed so far for the exploitation of such energy source. In the present preliminary work, two different geometry modules were tested under atmospheric pressure (i.e. forward osmosis or depressurized-PRO conditions). The first one is a conventional planar geometry cell. The second is a customized cylindrical membrane module, able to mechanically support the osmotic membrane along with the spacers. The latter, thanks to its design, allows membranes and spacers to be easily changed for testing purposes. A novel simplified proced…
Modeling of Magnetic-Field-Assisted Fluidization: Model Development and CFD Simulation of Magnetically Stabilized Fluidized Beds
2014
Magnetic-field-assisted fluidization is starting to be considered as a viable alternative to standard fluidized beds for those operations (such as particle separations, filtration, adsorption) in which the solid phase can be made of magnetic particles or, alternatively, the fluidizing agent is a ferro-fluid; thus the fluid bed responds to the action of magnetic fields, and stabilized fluidization regimes can be generated. One of the major difficulties to be tackled is the development of a predictive model capable of estimating the stabilized-to-bubbling transition velocity for a given magnetic field or, on the other hand, the magnetic field intensity required to stabilize the bed to a quies…
On the bubbling dynamics of binary mixtures of powders in 2D gas-solid fluidized beds
2012
Abstract The bubbling behavior of fluidized beds has been thoroughly investigated in the last decades by means of several techniques (e.g. X-ray, Inductance, Resistance and Impedance based techniques). In recent years, Digital Image Analysis Techniques have shown their potential for accurate and cost effective measurements. Most of the works related to the experimental analysis of bubble behavior in the field of gas-solid fluidization actually deal with monodispersed particles although almost all industrial equipments operate with mixtures of particles. Among the works available in literature dealing with mixtures of particles having different diameters and/or densities, most of them aim at…
Quasi-isoactinic reactor for photocatalytic kinetics studies
2007
Photochemical reactors characterized by almost uniform values of the local volumetric rate of photon absorption (LVRPA), i.e., quasi-isoactinic photoreactors, are particularly suitable for assessing the influence of radiant field intensity in kinetic studies. In this work, Monte Carlo simulations have been performed to obtain LVRPA values in a flat photoreactor irradiated on both sides. This configuration appears to be particularly suitable for obtaining quasi-isoactinic conditions. The influence of catalyst albedo and scattering phase function is assessed, and the conditions for obtaining iso-actinicity are discussed. Finally, these conditions are related to an easy-to-measure parameter, n…
Experimental analysis of bubble size distributions in 2D gas fluidized beds
2010
Abstract The present work focuses on the development of a novel statistical approach for the analysis of the behavior of a 2D fluidized bed operating under bubbling and slugging conditions. Experimental data were collected by means of a purposely built lab-scale 2D fluidized bed and an original digital image analysis technique (DIAT), allowing the acquisition of a number of data sufficient to perform a statistical analysis of bubble dynamics. In particular, measurements of bubble size distributions (BSD) along the bed were performed. The analysis allowed to characterize the shape of BSD for different particle systems and fluidization gas velocities; interestingly a bimodal shape of BSD is o…
Estimating radiant fields in flat heterogeneous photoreactors by the six-flux model
2006
Heterogeneous photoreactor modeling is a task complicated by the integro-differential nature of the Radiation Transfer Equation (RTE) when scattering phenomena are important. In the present work, a novel “Six Flux Model” (SFM) is proposed, which may be regarded as a step forward with respect to the previously proposed “Two Flux Model” (TFM). In order to validate the newly proposed model, Monte Carlo simulations of an indefinite plane-slab photoreactor have been performed. As no simplifying assumptions are involved in this case, the information obtained may be regarded as “pseudo-experimental,” and therefore compared with the predictions of both TFM and SFM models. Results show that the nove…
XPL and the Synchronization of Multimodal User Interfaces based on Design Pattern
2008
The great diversity of presentations in software applications deals with fulfilment of various types of user interface constructions related to different programming languages. Furthermore, the growing interest for multimodal applications entails that their user interfaces have to support multiple access channels within a single development framework. User Interfaces Design Patterns (UIDPs) are helpful to define interaction schemas between user and computer and they provide remarkable tools for the design and reuse of software components. This paper describes the eXtensible Presentation architecture and Language (XPL), a framework aimed at streamlining multi-channel interface design process…
The hydraulic behaviour of the simulacrum of the Outer Vertical Target of an ITER divertor cassette
2007
XPL the Extensible Presentation Language
2009
The last decade has witnessed a growing interest in the development of web interfaces enabling both multiple ways to access contents and, at the same time, fruition by multiple modalities of interaction (point-and-click, contents reading, voice commands, gestures, etc.). In this paper we describe a framework aimed at streamlining the design process of multi-channel, multimodal interfaces enabling full reuse of software components. This framework is called the eXtensible Presentation architecture and Language (XPL), a presentation language based on design pattern paradigm that keeps separated the presentation layer from the underlying programming logic. The language supplies a methodology to…
CFD prediction of bubble behavior in two-dimensional gas-solid fluidized beds
2009
This work focuses on the computational fluid dynamics (CFD) simulation of a laboratory-scale, two-dimensional fluidized bed and the relevant experiments in order to validate the prediction capability of the adopted codes and models. Both experimental and computational quantitative data were analyzed by means of an original digital image analysis technique, allowing for coherent comparison of computational and experimental results. In particular, this work analyzes the capability of the CFD simulations in predicting the fluctuating behavior of bubbling fluidized beds by means of frequency analysis of bubble-related phenomena.
Concentrazioni di gas radon in ambienti lavorativi di diverse regioni italiane
2008
MODELING OF A TiO2-COATED QUARTZ -WOOL PACKED-BED PHOTOCATALYTIC REACTOR
2010
A fixed-bed, photocatalytic laboratory reactor aimed to degrade pollutants from water streams was designed and built. Quartz wool coated with a thin film of TiO2 was employed as the reactor filling. The photocatalyst was placed in the reactor forming a loose packing to guarantee the intimate contact among reactants, photons, and the photocatalytic surface. This reactor was employed to study the photocatalytic decomposition of a model pollutant (formic acid). A reactor–radiation–reaction model was developed, which was comprised of the reactor mass balance, radiation model, and kinetic model for the degradation of formic acid. The local superficial rate of photon absorption, which was necessa…
Gas-Fluidization Characteristics of Binary Mixtures of Particles in 2D Geometry
2012
The bubbling behaviour of fluidized beds has been thoroughly investigated in the last decades by means of several techniques, e.g. X-ray, Inductance, Resistance and Impedance based techniques, PIV. In recent years, Digital Image Analysis Techniques have shown their potential for accurate and cost effectively measurements.Most of the work related to bubble behaviour analysis deals with single-sized particles, while almost all industrial equipment operates with multi-sized particles. Although considerable work has been done in the past with focus on the analysis of the mixing-segregation behaviour and predictions of fluid dynamics regime transitions, a lack of knowledge still exists in the an…
Enabling Multimodal Interaction in XPL – the eXtensible Presentation Language
2007
This paper introduces the multimodal extension of the eXtensible Presentation architecture and Language (XPL), a framework aimed at streamlining multi-channel interface design process and enabling full component reuse. XPL incorporates a presentation language based on design pattern paradigm, which supplies a clear distinction between the presentation layer and the corresponding programming logic, promoting contents aggregation and a variety of event handlers described without relying on a (procedural) scripting language. In this paper, the design pattern concept is extended to voice-based interaction, and two verbal design pattern (VeDP) are introduced along to their visual counterparts. T…
Misura della concentrazione di Radon in diverse sedi lavorative distribuite sul territorio nazionale
2007
Thermo-mechanical testing of Li-ceramic for the helium cooled pebble bed (HCPB) breeding blanket
2004
The helium cooled pebble bed (HCPB) Test blanket module (TBM) for the DEMO Reactor foresees the utilization of lithiate ceramics as breeder in form of pebble beds. The pebbles are organized in several layers alternatively stacked among couples of cooling plates (CP). ENEA has launched an experimental programme for the out-of-pile thermo-mechanical testing of mock-ups simulating a portion of the HCPB-TBM. The programme foresees the fabrication and testing of different mock-ups, to be tested in the HE-FUS3 facility at ENEA Brasimone. The paper describes the HELICHETTA III campaign carried-out in 2003. In particular, the test section layout, the pebble filling procedure, the experimental set-u…
Measurement of Multiphase Flow Characteristics Via Image Analysis Techniques: The Fluidization Case Study
2012
In this chapter, an overview on some imaging-based experimental techniques for the analysis of complex multiphase systems is reported. In particular, some techniques aimed at the study of fluidization dynamics will be analyzed and discussed, as developed by our research group
Analysis of the bubbling behaviour of 2D gas solid fluidized beds
2008
Abstract In the field of gas–solid fluidization, bubbles, and all features regarding them, have a very great importance, as they significantly affect the process performance. Numerous experimental studies on bubbles, and their formation, evolution, and properties, have been performed in the past. These investigations appear particularly difficult, due to the nature of these systems, since the gas phase is distributed in both the bubble and the emulsion phase. Several experimental approaches have been developed to tackle this study. Among these, the Digital Image Analysis Technique purposely developed in Part I of the present work, based on the use of a video camera for monitoring the phenom…
Solid–Liquid Suspensions in Top-Covered Unbaffled Vessels: Influence of Particle Size, Liquid Viscosity, Impeller Size, and Clearance
2014
Particle suspension in liquids is a unit operation commonly encountered in the process industry. Although it is usually carried out in baffled stirred tanks, there are some specific applications where the presence of baffles may be undesirable. In the present work solid-liquid suspensions are investigated in a radially stirred unbaffled tank provided with a top cover. The minimum impeller speed at which all solid particles get suspended (Njs) and the relevant power requirements (Pjs) are assessed. The dependence of these two parameters on physical properties (liquid viscosity, particle concentration, and size) and system geometrical configurations (impeller diameter and clearance) is invest…
Radiation model of a TiO2-coated, quartz wool, packed-bed photocatalytic reactor
2010
The radiation field of a packed-bed photocatalytic reactor filled with quartz wool coated with titanium dioxide was modeled using the Monte Carlo technique and the following information: the radiation flux emitted by the lamps, the diameter size distribution of the quartz fiber cloth, the mass of quartz fibers and of TiO2 that was immobilized on the fiber surface as well as the refractive index and the spectral absorption coefficient of the materials of the system. Modeling predictions were validated with radiometer measurements of the transmitted radiation through the reactor, the root mean square error being < 9.7%. Finally, by means of a parametric study, the validated model was used to …
Linear stability analysis of gas-fluidized beds for the prediction of incipient bubbling conditions
2010
Abstract This work focuses on the development of a novel linear stability criterion for the state of homogeneous fluidization regime, based on a new mathematical model for gas-fluidized beds. The model is developed starting from the well-known particle bed model. A mono-dimensional momentum balance is derived leading to a set of equations which explicitly include voidage-gradient dependent terms (elastic force) for both solid and fluid phases. A fully predictive criterion for the stability of homogeneous fluidization state is here proposed, based on the well-known Wallis’ linear stability analysis. The criterion requires the choice of an appropriate averaging distance, which in the present …
Le architetture ferroviarie della Sicilia Centrale: analisi tipologico-costruttiva
2012
Caratterizzata in principio dalla contrapposizione tra realtà contrastanti, tradizione e innovazione ovvero storicismo e modernismo, l’architettura ferroviaria si ritrova più volte al centro del dibattito architettonico, nel tentativo di individuare un linguaggio formale specifico e connotativo per questa tipologia. Questo tema si ripropone spesso, trattandosi di manufatti soggetti da una parte allo scorrere del tempo inteso come evoluzione tecnica, dall’altra allo scorrere del tempo come mutamento del contesto e delle esigenze dell’utenza. L’adeguarsi al continuo divenire delle evoluzioni tecnologiche e dei mutamenti sociali, che comportano l’erogazione di nuovi servizi, costituisce un pot…
On a computational study of the hydraulic behavior of the ITER divertor cassette full-scale prototype
2009
Studio della risposta nucleare del Water-Cooled Lithium Lead Test Blanket Module nel reattore ITER-FEAT
2002
Studio del comportamento termico di letti di sfere tramite il metodo dell’impulso di corrente
2003
On the nuclear response of the HCLL-TBM in ITER-FEAT
2003
HEXCALIBER TEST SECTION. Preliminary thermo-mechanical analysis
2007
On the thermal conductivity of a single size beryllium pebble bed
2002
Thermal analysis of the Helium-Cooled Lithium Lead Test Blanket Module to be irradiated in ITER
2009
Lab-scale investigation of a pressure retarded osmosis module fed by "non-conventional" salinity gradient
2015
Aim of this work has been to investigate the feasibility of PRO technology for power generation from saline streams originated by different water treatments plants, namely brine from a thermal desalination plant and fresh water from a sewage treatment plant.
Fusion pebble bed thermo-mechanical modelling. Status of the research activity at the DIN
2002
Analysis, by RELAP5 code, of Boron Dilution Phenomena in a Small Break LOCA Transient, Performed in PKL III E2.2 Test
2007
On the use of the Porous Elasticity and the Drucker-Prager models in the numerical simulations of the pebble beds thermo-mechanical behavior
2000
Fusion pebble bed thermo-mechanical modelling. Final report A. Status of the research activity at the DIN
2002
On the nuclear impact of different coolants in the HCLL-TBM in ITER-FEAT
2003
Fusion pebble bed thermo-mechanical modelling. Final report B. Coupled thermo-mechanical analyses in presence of volumetric heat sources
2002
La sezione di prova HELICHETTA. Analisi termomeccaniche numeriche e sperimentali
2003
Fruition and valorisation of disused manufacturing settlements: the "tonnare" of the Gulf of Castellammare case-studies. The Gulf of Castellammare: s…
2013
The issue about enhancement, fruition and management of manufacturing settlements, obsolete in relation with technological developments is not new and stands still at the centre of a heated debate, full of causes for reflection. Buildings assigned to fishing, processing and conservation of tuna (called tonnare) are emblematic. Process of decay involved Castellammare territory, in Sicily, wich is characterized by the presence of many artefacts.