Higher Institute on Territorial Systems for Innovation
PORTO Publications Open Repository TOrinoNot a member yet
91193 research outputs found
Sort by
Worst-case EMC investigation of single-wire transmission lines based on taylor arithmetic
No full textElectromagnetic compatibility (EMC) investigations often involve the assessment of whether signal integrity (SI) and radiated susceptibility (RS) in transmission lines comply with design margins and/or maximum levels provided by EMC regulations. Hence, worst-case analysis is a useful tool to flag potential problems in the early design stage. This paper presents a novel paradigm for the worst-case SI/RS analysis of single-wire transmission lines. The method is based on the theoretical framework of Taylor arithmetic, which represents each variable as a Taylor expansion, function of the selected design parameter, complemented by an interval remainder that encompasses all approximation and round-off errors in a conservative way. A suitable modification of the basic algebraic and nonlinear operations allows propagating this representation from the input design parameter to the desired outputs. The methodology is applied to the SI analysis of a coaxial cable with uncertain shield radius, and to the RS assessment of a wire illuminated by an impinging plane wave with uncertain polarization
LUP and multi-risk: The mutual influence of natural and anthropic impacts
No full textIn Italy, the different territorial risks are managed through completely separate plans, that the Municipalities (local scale) should apply on their territory with direct interventions; anyway, the current approach, which does not consider the interactions between risks, could decrease the efficiency of the planning and emergency actions. Therefore, the research here exposed, deriving from a PhD thesis, aimed at developing a quick and easy to use methodology, able to identify and rate the main risks which characterize a territory, and to simulate the possible effects of their interaction on the territorial and environmental vulnerabilities. The methodology was tested on the case study of Mantua, where both industrial, seismic and hydrogeological risks are present. Each step of the methodology proceeds simultaneously with a GIS Map, which helps to spatially understand the extension and gravity of each risk
Anomaly Detection in a Reactor Coolant Pump Flywheel System via Pulse Shape Analysis
No full textIn this study, a method that discriminates between anomalies present or absent in the vibration signal of a flywheel system is developed. First by means of MATLAB and Simulink, a simple flywheel system under different feasible conditions is simulated using equations of motion to capture the dynamic behaviors of the components of the system along their lines of action. The resulting vibration signals obtained from the simulations are combined with varying levels of noise and then subjected to pulse shape analysis (PSA). PSA is a tool that has been mostly used in the field of nuclear engineering, and it is explored and used differently here with the objective of developing a suitable PSA algorithm that can differentiate between vibration signals based on the presence or absence of an anomaly. The algorithm is a time-domain technique with minimal computational time that can be very easily applied. At the end, it is shown that the developed PSA algorithm can identify an anomaly in a vibration signal on the basis of a defined pattern under certain attainable conditions
Thermomechanical Response of Advanced Materials under Quasi Instantaneous Heating
No full textThe study of the thermomechanical response of materials to a time dependent heat load is of paramount importance in the design of a variety of components widely adopted in the industry and in research laboratories. Three regimes can be identified in the thermomechanical problem, depending on the heating rate: quasi static, slow transient and quasi instantaneous heating. This PhD thesis focuses on the latter scenario, where the heat deposition rate is high enough to lead to the origination of stress waves, propagating from the locally-heated zone to the surrounding of the structure, and superposing with the quasi-static stress field. In the first part of the thesis, the dynamic response of materials to quasi instantaneous heating is evaluated as a function of the stress waves generated. At low thermal energies, stress waves remain below the yield stress of the material, in the elastic regime. When the amplitude of the wave surpasses the yield stress of the material, plasticity takes place and the signal is dispersed into an elastic wave travelling at the speed of sound, and plastic waves at lower velocity. Finally, the shock regime can be attained only at critical levels of energy and pressure induced by the fast heating. This scenario features a sharp discontinuity in temperature, pressure and density, requiring the adoption of finite element codes for the solution of the thermomechanical problem. The hydrostatic response of shocked materials depends on the equation of state (EOS), while the deviatoric contribution to the stress tensor is controlled by the strength model. Failure models govern fracture mechanisms due to void coalescence, spallation and micro spallation. Examples of the main categories of EOS, strength and failure models, are given in this thesis. A new method to explore unusual regions of the EOS, based on intense isochoric heating driven by particle beams, is also introduced. In the second part of the thesis, the several phenomena induced by a quasi instantaneous heating, due to particle beam impact on the matter, are explored in detail. Such phenomena involve changes of phase, cylindrical pressure waves at the elastic, plastic and shock regime, as well as spallation and micro spallation fracture. To explore each of these mechanisms, numerical studies by means of implicit and explicit finite element codes are presented and combined, when available, with analytical methods and experimental tests performed in particle accelerator facilities. In the final part of the thesis, the studies performed are applied to the design and engineering of CERN HL LHC accelerator components known as collimators. These components, closely interacting with the beam particles, are potentially submitted to accidental impacts, whose consequences on the collimator and on the overall machine must be minimized. With this goal, new composites were developed at CERN in recent years to replace the carbon fibre reinforced carbon (CFC) currently adopted in the present LHC, combining the good thermal and electrical properties of metals with the high thermal stability of carbon allotropes such as graphite and diamond. The most promising ones are Copper Diamond (CuCD) and Molybdenum Graphite (MoGr); these materials were fully characterized in order to derive EOS and constitutive models necessary for the study of their response under intense isochoric heating. To prove the accuracy of such models, and to experimentally verify the collimator resistance under the direct impact of proton beams involving energy densities typical of the HL LHC design scenarios, a test was devised and performed in 2015 at the CERN HiRadMat facility. Three collimator jaws, in CFC, MoGr and CuCD, were extensively instrumented, and submitted to proton impacts at increasing intensities. Experimental results of the tests and comparisons with the numerical predictions are presented
Decision Support Tool for Multi-Criteria Analyses of the Quality of Large Building Stock
No full textTheory of Games and Contracts to define the Client role in Building Information Modeling
No full text
Car as a moving meteorological integrated sensor
No full textNowadays, common cars are equipped with set of sensors, systems and technologies commonly used to improve car and passengers' safety and comfort. These cars are often referred to with the innovative conception of "car as a sensor". A car can be also thought as a moving integrated weather sensor since it can provide meteorological information along specific tracks, exploiting all the information acquired by the installed sensors processed by specific ad-hoc software and technologies. The paper will present an analysis of the sensor installed on car with a panoramic of the software and technologies that can be used to use the car as integrated moving sensor for meteorological purposes, including also some communications techniques. The descriptions of some activities are presented, some technical points are addressed and some examples of applications are reported
Thermal Stability and Fire Retardant Properties of Polyamide 11 Microcomposites containing different Lignins
No full textThis study investigates the influence of various lignins and their content on the thermal stability and fire retardancy of bio-based polyamide 11 (PA). Microcomposites based on PA and containing 5, 10, 15 and 20 wt.% of different lignins were prepared with a twin-screw extruder. Morphological analysis showed good interfacial interaction and uniform distribution of lignin particles within the resulting microcomposites. Further, thermogravimetric analyses carried out in inert atmosphere indicated that, unlike kraft lignin, which is able to give rise to the formation of lower char residue (41 - 48 wt.% at 600 °C), the sulphonated counterpart provides a higher thermal stability as well as a higher char residue (55 - 58 wt.%). Furthermore, vertical flame spread tests clearly showed that 15 wt.% is the optimum of kraft or sulphonated lignin loading to achieve improved flame retardant properties and V1 rating. In addition, cone calorimeter was exploited to study forced combustion behaviour; in particular the microcomposites containing sulphonated lignin revealed a significant reduction of peak of heat release rate (-51%), of total heat release (-23%) and a lower average mass loss rate together with a noticeable increase of the final residual mass (about 9 wt.%). Conversely, the microcomposites containing kraft lignins showed opposite effect, since HRR and THR values increased in the presence of kraft lignin
Promising Antimicrobial Properties of Silicon-Based Thin-Film Coatings
No full textSilicon-based thin films, such as silicon and silicon-based alloys, have been intensively studied, especially for their use in microelectronics and large area electronics. However, they also show interesting properties regarding their biological interaction, although these characteristics have been studied to a lower extent. Recently, promising antibacterial properties of some silicon-based materials have been investigated, showing their potential ability to reduce the adhesion of some types of bacteria on the surfaces onto which they are applied. Since these properties rely on the reduction of bacterial adhesion, instead of exploiting the release of antibacterial agents such as Ag ions or nanoparticles, they show the advantage of preventing potentially harmful long-time effects that could be exerted by these agents in the host tissues. Moreover, this approach avoids the risk that the release intensity of these agents is reduced over time due to their depletion inside the material. Due to the wide range of interesting properties of silicon-based materials, including biocompatibility increase, barrier action against the release of chemicals, and tuning of surface energy, the production of multifunctional coatings could also be possible. In this chapter, the most important properties of silicon-based thin films are reviewed, and some results concerning the potential antibacterial properties of silicon-oxygen amorphous thin-film alloys (a-SiOx) are presented in detail