Tiziano Leidi

Bio: Tiziano Leidi is an academic researcher from SUPSI. The author has contributed to research in topics: Lattice Boltzmann methods & Stream processing. The author has an hindex of 8, co-authored 26 publications receiving 141 citations.

Design and implementation of industrial automation control systems: A survey

Abstract: The level of automation in factories and plants, and the need for their fast design and customization, increases steadily. These systems are often designed with various means, and controlled by heterogeneous embedded hard- and software. These circumstances raise the problem complexity and the time to be invested. The state-of-the art and the trends in design and engineering for the industrial automation have not yet provided an applicable solution to the mentioned issues. Hence a new European project tries to overcome the previous problems with a new component based approach for automatically linking the design and implementation phases. This document resumes and analyses the results of a survey conducted among the project industrial partners about their current design and implementation processes. What emerges is the need and the lack of connection, and even transformation rules, between the two aforementioned processes.

Surface growth effects on reactive capillary-driven flow: Lattice Boltzmann investigation

Abstract: The Washburn law has always played a critical role for ceramics. In the microscale, surface forces take over volume forces and the phenomenon of spontaneous infiltration in narrow interstices becomes of particular relevance. The Lattice Boltzmann method is applied in order to ascertain the role of surface reaction and subsequent deformation of a single capillary in 2D for the linear Washburn behavior. The proposed investigation is motivated by the problem of reactive infiltration of molten silicon into carbon preforms. This is a complex phenomenon arising from the interplay between fluid flow, the transition to wetting, surface growth and heat transfer. Furthermore, it is characterized by slow infiltration velocities in narrow interstices resulting in small Reynolds numbers that are difficult to reproduce with a single capillary. In our simulations, several geometric characteristics for the capillaries are considered, as well as different infiltration and reaction conditions. The main result of ou...

Surface growth effects on reactive capillary-driven flow: Lattice Boltzmann investigation

Abstract: The Washburn law has always played a critical role for ceramics. In the microscale, surface forces take over volume forces and the phenomenon of spontaneous infiltration in narrow interstices becomes of particular relevance. The Lattice Boltzmann method is applied in order to ascertain the role of surface reaction and subsequent deformation of a single capillary in 2D for the linear Washburn behavior. The proposed investigation is motivated by the problem of reactive infiltration of molten silicon into carbon preforms. This is a complex phenomenon arising from the interplay between fluid flow, the transition to wetting, surface growth and heat transfer. Furthermore, it is characterized by slow infiltration velocities in narrow interstices resulting in small Reynolds numbers that are difficult to reproduce with a single capillary. In our simulations, several geometric characteristics for the capillaries are considered, as well as different infiltration and reaction conditions. The main result of our work is that the phenomenon of pore closure can be regarded as independent of the infiltration velocity, and in turn a number of other parameters. The instrumental conclusion drawn from our simulations is that short pores with wide openings and a round-shaped morphology near the throats represent the optimal configuration for the underlying structure of the porous preform in order to achieve faster infiltration. The role of the approximations is discussed in detail and the robustness of our findings is assessed.

Simulation of capillary infiltration into packing structures for the optimization of ceramic materials using the lattice Boltzmann method

Abstract: This study uses the lattice Boltzmann method (LBM) to simulate in 2D the capillary infiltration into porous structures obtained from the packing of particles. The experimental problem motivating the work is the densification of carbon preforms by reactive melt infiltration. The aim is to determine the optimization principles for the manufacturing of high-performance ceramics. Simulations are performed for packings with varying structural properties. The results suggest that the observed slow infiltrations can be ascribed to interface dynamics. Pinning represents the primary factor retarding fluid penetration. The mechanism responsible for this phenomenon is analyzed in detail. When surface growth is allowed, it is found that the phenomenon of pinning becomes stronger. Systems trying to reproduce typical experimental conditions are also investigated. It turns out that the standard for accurate simulations is challenging. The primary obstacle to overcome for enhanced accuracy seems to be the over-oc...

Lattice Boltzmann simulations on the role of channel structure for reactive capillary infiltration

Abstract: It is widely recognized that the structure of porous media is of relevance for a variety of mechanical and physical phenomena. The focus of the present work is on capillarity, a pore-scale process occurring at the micron scale. We attempt to characterize the influence of pore shape for capillary infiltration by means of Lattice Boltzmann simulations in 2D with reactive boundaries leading to surface growth and ultimately to pore closure. The systems under investigation consist of single channels with different simplified morphologies: namely, periodic profiles with sinusoidal, step-shaped and zigzag walls, as well as constrictions and expansions with rectangular, convex and concave steps. This is a useful way to break the complexity of typical porous media down into basic structures. The simulations show that the minimum radius alone fails to properly characterize the infiltration dynamics. The structure of the channels emerges as the dominant property controlling the process. A factor responsible for this...

An overview of AspectJ

Abstract: Aspect] is a simple and practical aspect-oriented extension to Java With just a few new constructs, AspectJ provides support for modular implementation of a range of crosscutting concerns. In AspectJ's dynamic join point model, join points are well-defined points in the execution of the program; pointcuts are collections of join points; advice are special method-like constructs that can be attached to pointcuts; and aspects are modular units of crosscutting implementation, comprising pointcuts, advice, and ordinary Java member declarations. AspectJ code is compiled into standard Java bytecode. Simple extensions to existing Java development environments make it possible to browse the crosscutting structure of aspects in the same kind of way as one browses the inheritance structure of classes. Several examples show that AspectJ is powerful, and that programs written using it are easy to understand.

IEC 61499 as Enabler of Distributed and Intelligent Automation: State-of-the-Art Review

Abstract: This review paper discusses the industrial and research activities around the IEC 61499 architecture for distributed automation systems. IEC 61499 has been developed to enable intelligent automation where the intelligence is genuinely decentralized and embedded into software components, which can be freely distributed across networked devices. With the recent emergence of professionally made software tools and dozens of hardware platforms, IEC 61499 is getting recognition in industry. This paper reviews research results related to the design of distributed automation systems with IEC 61499, the supporting tools and the aspects related to the execution of IEC 61499 on embedded devices. The promising application areas of IEC 61499 include flexible material handling systems, in particular airport baggage handling, flexible reconfigurable manufacturing automation, intelligent power distribution networks and SmartGrid, as well as the wide range of embedded networked systems.

Software Factories: Assembling Applications with Patterns, Models, Frameworks and Tools

Abstract: Increasingly complex and rapidly changing requirements and technologies are making application development increasingly difficult. This talk examines this phenomenon, and presents a simple pattern for building languages, patterns, frameworks and tools for specific domains, such as user interface construction or database design. Software Factories integrate critical innovations in adaptive assembly, software product lines, and model driven development to reduce the cost of implementing this pattern, making it cost effective for narrower and more specialized domains, such as B2B commerce and employee self service portals.