Higher Institute on Territorial Systems for Innovation
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Origami Pythagorean Tree, Natural Numbers' Powers, Sum and Series
No full textWe show an example of a lesson, tested with teen-agers and children, in which, by developing an idea of Albert E. Bosman, we propose an origami model to depict geometric forms in order to help learning of arithmetical topics such as powers of natural numbers and their sum, and also the principle of induction, with a tactile, visual and motion experience
Real operation data analysis on district heating load patterns
No full textDistrict heating networks play an important role in the heating and cooling sector, serving up to 60% of the citizens in some countries. The availability of a thermal network supplying multiple users allows producing heat from different sources and multiple technologies. The possibility of relying on different solutions allows the system manager to optimize the heat generation by choosing the best unit for each operation condition. This choice is based on a deep knowledge of heat load profiles, that are related to users' behavior, network performances and control logics. This paper provides an analysis of a DH system operation over ten heating seasons, with the aim of highlighting the main characteristics of the heat load variations and finding the fundamental drivers for heat load prediction. Although the system has seen a significant development throughout the years, the specific energy consumption has been found to be comparable on the whole duration of the analysis. Two main patterns are highlighted, based on the different operation settings along the hours of the day and the outdoor temperature as the main weather driver for building's heat demand
Design of non conventional Synchronous Reluctance machine
No full textSynchronous reluctance (SyR) and Permanent magnet Synchronous Reluctance (PM-SyR) machines represent an answer to the growing emphasis on higher efficiency, higher torque density and overload capability of ac machines for variable-speed applications. Their high performance is particularly attractive in electric traction and industry applications. The SyR technology represents a convenient solution to obtain high efficiency machines at reduced cost and high reliability. The manufacturing costs are comparable to other existing technologies such as induction motors. Different SyR and PM-SyR machines with different ratings and applications were designed, for comparison with induction motors having equal frame. An accurate comparison between Induction motors, SyR and PM-SyR machines is reported, with reference to the IE4 and IE5 efficiency specifications that could become mandatory in the next years. Three studies are classified under the term "Non-Conventional" machines: Line-Start SyR motor: is a special SyR machine designed for constant speed applications, line supplied. The rotor flux barriers are filled with aluminum, to obtain a squirrel cage that resembles the one of an induction motor. The manufacturing costs are comparable to those of the induction motor, and the efficiency is higher. Two prototypes were realized and tested. FSW-SyR: tooth-wound coils and fractional slot per pole combinations were investigated. They are of interest because they permit a simplification and higher degree of automatization of the manufacturing process. However, FSW-SyR machines are known for their high torque ripple, low specific torque and power factor. The number of slots per pole was optimized to maximize the torque density. Dealing with the torque ripple, a lumped parameters model was used together with optimization in SyRE. A design with minimized ripple was obtained, comparable to a distributed winding machine in this respect. This design was prototyped and tested. Mild Overlapped SyR: this study shows a new winding configuration applied to SyR and PM-SyR machines. The proposed case is in the direction to find a hybrid solution between distributed winding and tooth winding motors, that permits to reduce costs and improve performances. One limitation of this solution is that only number of pole pairs equal to five or higher are feasible, and this reduces the applicability of the solution to classical industry applications, where one to three pole pairs are normally used
Embedded Systems Secure Path Verification at the HW/SW Interface
No full textEmbedded systems, like medical or automotive, require basic security functions, often referred to as "secure communications". Interest has been growing around defining and formally verifying security related properties, as potentially able to catch hard-to-detect problems. We follow novel research works focused on formalizing security requirements for information flow. We compare State Properties to Path Properties, as two approaches able to capture different aspects on how to leak/corrupt secure data via unexpected taints and paths. We also discuss tools used to verify Path and State properties, on two existing Secure Embedded Architectures, and we discuss the advantages and drawbacks of each approach
Improvement of Lap-Time of a Rear Wheel Drive Electric Racing Vehicle by a Novel Motor Torque Control Strategy
No full textThis paper presents a novel strategy for the control of the motor torques of a rear wheel drive electric vehicle with the objective of improving the lap time of the vehicle around a racetrack. The control strategy is based upon increasing the size of the friction circle by implementing torque vectoring and tire slip control. A two-level nested control strategy is used for the motor torque control. While the outer level is responsible for computing the desired corrective torque vectoring yaw moment, the inner level controls the motor torques to realize the desired corrective torque vectoring yaw moment while simultaneously controlling the wheel longitudinal slip. The performance of the developed controller is analyzed by simulating laps around a racetrack with a non-linear multi-body vehicle model and a professional human racing driver controller setting. The advantage of the developed control strategy is studied by looking qualitatively and quantitatively at the sectors of the track where the controlled vehicle gains lap time. Simulation results indicate improvement in the vehicle controllability due to oversteer control and in the racetrack lap time due to better utilization of the available tire grip
Assessment of Cost and Energy Requirements of Electron Beam Melting (EBM) and Machining Processes
No full textAdditive Manufacturing is under the spotlight as potential disruptive technology, particularly for the production of complex-shaped structural metallic components. However, the actual AM process capabilities present some limitations in achieving the strict part quality requirements imposed by the aerospace and automotive sectors. Therefore, the integration of AM and conventional manufacturing represents an emerging scenario to be investigated. In this paper, a pure machining process and a hybrid production route (based on EBM and finish machining) are compared. The influence of material usage-related factors on costs and energy demand is discussed. The results prove that, despite precise process judgments are case-specific, the proposed methodologies are suitable to provide guidelines for identifying the optimal manufacturing route under multiple design objectives
Composition law of κ-entropy for statistically independent systems
No full textThe intriguing and still open question concerning the composition law of κ--entropy is here reconsidered and solved. It is shown that, for a statistical system described by a probability distribution, made up of two statistically independent subsystems, described through the probability distributions p and q respectively, the joint κ--entropy S(q,p) can be obtained starting from the κ--entropies, S(q) and S(P), and additionally from the κ--entropic functionals S(q/e), S(p/e) , being e the κ-Napier number. The composition law of the κ-entropy is given in closed form and emerges as a one-parameter generalization of the ordinary additivity law of Boltzmann-Shannon entropy recovered in the κ→0 limit