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A Fiber Optic Probe for Tumor Laser Ablation with Integrated Temperature Measurement Capability
No full textThe paper presents the characterization results of a new all-optical applicator for improved tumor laser ablation treatments that features customized irradiation pattern and builtin temperature sensors. The probe exploits a double cladding optical fiber to integrate some Bragg gratings acting as temperature sensing elements in the core, while guiding the high power beam used for the ablation in the inner cladding. The assessment of the probe behavior has been conducted in two steps: first, with an agar gel phantom to characterize the irradiation pattern and to validate the Bragg grating based measurement setup in comparison with a thermographic camera; then, simulating actual treatments using an ex-vivo animal liver
Multi-gate FinFET Mixer Variability assessment through physics-based simulation
No full textIn this paper we show that innovative physics-based simulations can be used for a comprehensive analysis of RF stages subject to random variations of technological parameters, including the computation of the average (deterministic) RF performance along with their statistical deviation. The variability analysis is addressed by means of the recently developed physicsbased sensitivity analysis of AC parameters through Green's functions [1], [2]. To demonstrate the technique, we address the analysis of a FinFET mixer exploiting an innovative Independent Gates topology, showing that a careful design allows to maximize the mixer conversion gain while minimizing its variability vs. several physical parameters, such as the gate length, oxide thickness and fin width
Nucleic acids from agro-industrial wastes: a green recovery method for fire retardant applications
No full textTwo different agro-industrial biological wastes, namely spent brewer's yeast and vegetable scraps have been considered as inexpensive sources of nucleic acids (NAs) to be employed for conferring flame retardant features to cotton fabrics. A simple, cheap and green extraction method has been set-up for each matrix. The yields, purity grades and molecular sizes have been assessed and compared with two different commercially available purified DNA. The developed extraction procedures have shown a high level of reliability for the recovery of nucleic acids from both agro-industrial wastes. The results of the flammability tests with the extracted NAs clearly indicated that, the add-on value on the fabrics being equal, the NAs extracted from spent brewer's yeast cells are able to provide self-extinction to cotton and reproduce the fire behaviour obtained with highly expensive commercially purified DNAs. Thus, the proposed procedures may be applied for large-scale NA recovery from inexpensive agro-food wastes to obtain partially purified NA suitable for fire retardant applications. Moreover, the developed extraction procedures can be considered an addition to the growing body of more rational waste valorisation techniques within the bio-refinery approach and circular economy concept
Effects of rockfall on an elastic-plastic member: A novel compliance contact model and dynamic response
No full textThe study presents the dynamic structural response of steel member subjected to a localized impact from falling rock blocks in rockfall areas. A novel compliance contact model is derived for the interaction between the elastic-plastic member (the target) and an impacting rock block. Unlike other existing models, the proposed compliance contact model accurately evaluates the material properties of the rock block (considered as a deformable indenter) and of the steel target (considered as an elastic-plastic target of finite thickness). A simplified two degrees of freedom (2-DOF) lumped masses model accounting for nonlinear contact interaction and material nonlinearities is used to describe the dynamics of the phenomenon. The proposed contact law and the 2-DOF model are validated with detailed static and dynamic analyses conducted with finite element software ANSYS. The results are compared and commented in order to be implemented in future civil engineering applications
The cogging torque measurement through a new validated methodology
No full textThe recent activity of the authors, concerning different types of small PM machines, brought to the necessity to measure the respective cogging torques. Normally such a measure (including the hysteresis and bearing torque components), is realized with a prime motor to drag the machine under exam at very low speed and adopting a very good gearbox (classical method). During the activity a new method has been introduced adopting a step motor dragging directly the machine to be tested. The measure has been carried out with both systems; the results obtained with the classical method constitute the reference for the new one adopting the step motor, with a very good agreement. The reason to adopt the new method is related to the great elasticity which the step motor and its control may allow; that appears useful, for example, to try to separate the actual cogging torque from the hysteresis and bearing torque components, which results impossible with the classical method
Personalised community maps
No full textWith the convergence of geographical information systems (GIS) and internet technology, the public administration is starting to use online maps as a web-based bidirectional communication channel with the population: maps are used: i) in public portals, for publishing and crowdsourcing information about the territory; ii) in policy-making, for defining a community vision of the territory and for involving people in public choices. Both cases raise challenges related to the large amount of data handled in the maps, and to their lack of group collaboration support. We attempted to address these issues by developing an information-sharing model, and a testbed software application, that support group management and the generation of persistent, custom community maps focused on the user's interests. Our model builds on tag-based user profiles and on information filtering. This paper describes our model and the results of an evaluation of the GroupMapping application, based on it
Methodology for the Safety and Reliability assessment of hypersonic transportation systems in conceptual design activities
No full textOpen-source implementation of an ad-hoc IEEE802.11a/g/p software-defined radio on low-power and low-cost general purpose processors
No full textThis work proposes a low-cost and low-power software-defined radio open-source platform with IEEE 802.11 a/g/p wireless communication capability. A state-of-the-art version of the IEEE 802.11 a/g/p software for GNU Radio (a free and open-source software development framework) is available online, but we show here that its computational complexity prevents operations in low-power general purpose processors, even at throughputs below the standard. We therefore propose an evolution of this software that achieves a faster and lighter IEEE 802.11 a/g/p transmitter and receiver, suitable for low-power general purpose processors, for which GNU Radio provides very limited support; we discuss and describe the software radio processing structuring that is necessary to achieve the goal, providing a review of signal processing techniques. In particular, we emphasize the advanced reduced instruction set (RISC) machine (ARM) study case, for which we also optimize some of the processing libraries. The presented software will remain open-source
The role of new types of urban green for the environmental regeneration of the contemporary city
No full textContemporary cities are always more overheated for the anthropogenic effect linked to the general process of warming of the climate, but also because of their conformation, of vehicular traffic, of mineralized materials, and - in particular - of the decrease of the relation between built heritage and vegetable biomass. Instead the cities which have maintained large green surfaces inside them, have pleasing environmental conditions, because the vegetation, as well as improving the climate, filters out pollution, absorbs noise, increases biodiversity and contributes to many recreational, cultural and educational activities. Since the seventies, the green systems are starting to be seen as focal centers of the environmental regeneration of the city, both in the recovery of built heritage that in new buildings. In the last thirty years the structural integration of the green with the building envelope was a new challenge - even technological - for the project, which is outlined with green walls solutions, "green skin", vertical green, green roofs, etc. The paper aims to illustrate the new urban green types, designed as a microclimate control tool of urban areas, in order to improve the conditions of environmental and psychological wellbeing, especially in high-density residential areas and also to highlight the critical issues of a project culture which is not always able to fully control the new technological solutions of detail
Integration of Active Systems for a Global Chassis Control Design
No full textVehicle chassis control active systems (braking, suspension, steering and driveline), from the first ABS/ESC control unit to the current advanced driver assistance systems (ADAS), are progressively revolutionizing the way of thinking and designing the vehicle, improving its interaction with the surrounding world (V2V and V2X) and have led to excellent results in terms of safety and performances (dynamic behavior and drivability). They are usually referred as intelligent vehicles due to a software/hardware architecture able to assist the driver for achieving specific safety margin and/or optimal vehicle dynamic behavior. Moreover, industrial and academic communities agree that these technologies will progress till the diffusion of the so called autonomous cars which are able to drive robustly in a wide range of traffic scenarios. Different autonomous vehicles are already available in Europe, Japan and United States and several solutions have been proposed for smart cities and/or small public area like university campus. In this context, the present research activity aims at improving safety, comfort and performances through the integration of global active chassis control: the purposes are to study, design and implement control strategies to support the driver for achieving one or more final target among safety, comfort and performance. Specifically, the vehicle subsystems that are involved in the present research for active systems development are the steering system, the propulsion system, the transmission and the braking system. The thesis is divided into three sections related to different applications of active systems that, starting from a robust theoretical design procedure, are strongly supported by objective experimental results obtained fromHardware In the Loop (HIL) test rigs and/or proving ground testing sessions. The first chapter is dedicated to one of the most discussed topic about autonomous driving due to its impact from the social point of view and in terms of human error mitigation when the driver is not prompt enough. In particular, it is here analyzed the automated steering control which is already implemented for automatic parking and that could represent also a key element for conventional passenger car in emergency situation where a braking intervention is not enough for avoiding an imminent collision. The activity is focused on different steering controllers design and their implementation for an autonomous vehicle; an obstacle collision avoidance adaptation is introduced for future implementations. Three different controllers, Proportional Derivative (PD), PD+Feedforward (FF) e PD+Integral Sliding Mode (ISM), are designed for tracking a reference trajectory that can be modified in real-time for obstacle avoidance purposes. Furthermore, PD+FF and PD+ISM logic are able to improve the tracking performances of automated steering during cornering maneuvers, relevant fromthe collision avoidance point of view. Path tracking control and its obstacle avoidance enhancement is also shown during experimental tests executed in a proving ground through its implementation for an autonomous vehicle demonstrator. Even if the activity is presented for an autonomous vehicle, the active control can be developed also for a conventional vehicle equipped with an Electronic Power Steering (EPS) or Steer-by-wire architectures. The second chapter describes a Torque Vectoring (TV) control strategy, applied to a Fully Electric Vehicle (FEV) with four independent electric motor (one for each wheel), that aims to optimize the lateral vehicle behavior by a proper electric motor torque regulation. A yaw rate controller is presented and designed in order to achieve a desired steady-state lateral behaviour of the car (handling task). Furthermore, a sideslip angle controller is also integrated to preserve vehicle stability during emergency situations (safety task). LQR, LQR+FF and ISM strategies are formulated and explained for yaw rate and concurrent yaw rate/sideslip angle control techniques also comparing their advantages and weakness points. The TV strategy is implemented and calibrated on a FEV demonstrator by executing experimental maneuvers (step steer, skid pad, lane change and sequence of step steers) thus proving the efficacy of the proposed controller and the safety contribution guaranteed by the sideslip control. The TV could be also applied for internal combustion engine driven vehicles by installing specific torque vectoring differentials, able to distribute the torque generated by the engine to each wheel independently. The TV strategy evaluated in the second chapter can be influenced by the presence of a transmission between themotor (or the engine) and wheels (where the torque control is supposed to be designed): in addition to the mechanical delay introduced by transmission components, the presence of gears backlashes can provoke undesired noises and vibrations in presence of torque sign inversion. The last chapter is thus related to a new method for noises and vibration attenuation for a Dual Clutch Transmission (DCT). This is achieved in a new way by integrating the powertrain control with the braking system control, which are historically and conventionally analyzed and designed separately. It is showed that a torsional preload effect can be obtained on transmission components by increasing the wheel torque and concurrently applying a braking wheel torque. For this reason, a pressure following controller is presented and validated through a Hardware In the Loop (HIL) test rig in order to track a reference value of braking torque thus ensuring the desired preload effect and noises reduction. Experimental results demonstrates the efficacy of the controller, also opening new scenario for global chassis control design. Finally, some general conclusions are drawn and possible future activities and recommendations are proposed for further investigations or improvements with respect to the results shown in the present work