12 resultados para design based on origin

em AMS Tesi di Laurea - Alm@DL - Università di Bologna


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Hybrid vehicles represent the future for automakers, since they allow to improve the fuel economy and to reduce the pollutant emissions. A key component of the hybrid powertrain is the Energy Storage System, that determines the ability of the vehicle to store and reuse energy. Though electrified Energy Storage Systems (ESS), based on batteries and ultracapacitors, are a proven technology, Alternative Energy Storage Systems (AESS), based on mechanical, hydraulic and pneumatic devices, are gaining interest because they give the possibility of realizing low-cost mild-hybrid vehicles. Currently, most literature of design methodologies focuses on electric ESS, which are not suitable for AESS design. In this contest, The Ohio State University has developed an Alternative Energy Storage System design methodology. This work focuses on the development of driving cycle analysis methodology that is a key component of Alternative Energy Storage System design procedure. The proposed methodology is based on a statistical approach to analyzing driving schedules that represent the vehicle typical use. Driving data are broken up into power events sequence, namely traction and braking events, and for each of them, energy-related and dynamic metrics are calculated. By means of a clustering process and statistical synthesis methods, statistically-relevant metrics are determined. These metrics define cycle representative braking events. By using these events as inputs for the Alternative Energy Storage System design methodology, different system designs are obtained. Each of them is characterized by attributes, namely system volume and weight. In the last part the work, the designs are evaluated in simulation by introducing and calculating a metric related to the energy conversion efficiency. Finally, the designs are compared accounting for attributes and efficiency values. In order to automate the driving data extraction and synthesis process, a specific script Matlab based has been developed. Results show that the driving cycle analysis methodology, based on the statistical approach, allows to extract and synthesize cycle representative data. The designs based on cycle statistically-relevant metrics are properly sized and have satisfying efficiency values with respect to the expectations. An exception is the design based on the cycle worst-case scenario, corresponding to same approach adopted by the conventional electric ESS design methodologies. In this case, a heavy system with poor efficiency is produced. The proposed new methodology seems to be a valid and consistent support for Alternative Energy Storage System design.

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Through the use of Cloud Foundry "stack" concept, a new isolation is provided to the application running on the PaaS. A new deployment feature that can easily scale on distributed system, both public and private clouds.

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In the last twenty years aerospace and automotive industries started working widely with composite materials, which are not easy to test using classic Non-Destructive Inspection (NDI) techniques. Pairwise, the development of safety regulations sets higher and higher standards for the qualification and certification of those materials. In this thesis a new concept of a Non-Destructive defect detection technique is proposed, based on Ultrawide-Band (UWB) Synthetic Aperture Radar (SAR) imaging. Similar SAR methods are yet applied either in minefield [22] and head stroke [14] detection. Moreover feasibility studies have already demonstrated the validity of defect detection by means of UWB radars [12, 13]. The system was designed using a cheap commercial off-the-shelf radar device by Novelda and several tests of the developed system have been performed both on metallic specimen (aluminum plate) and on composite coupon (carbon fiber). The obtained results confirm the feasibility of the method and highlight the good performance of the developed system considered the radar resolution. In particular, the system is capable of discerning healthy coupons from damaged ones, and correctly reconstruct the reflectivity image of the tested defects, namely a 8 x 8 mm square bulge and a 5 mm drilled holes on metal specimen and a 5 mm drilled hole on composite coupon.

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In the field of Power Electronics, several types of motor control systems have been developed using STM microcontroller and power boards. In both industrial power applications and domestic appliances, power electronic inverters are widely used. Inverters are used to control the torque, speed, and position of the rotor in AC motor drives. An inverter delivers constant-voltage and constant-frequency power in uninterruptible power sources. Because inverter power supplies have a high-power consumption and low transfer efficiency rate, a three-phase sine wave AC power supply was created using the embedded system STM32, which has low power consumption and efficient speed. It has the capacity of output frequency of 50 Hz and the RMS of line voltage. STM32 embedded based Inverter is a power supply that integrates, reduced, and optimized the power electronics application that require hardware system, software, and application solution, including power architecture, techniques, and tools, approaches capable of performance on devices and equipment. Power inverters are currently used and implemented in green energy power system with low energy system such as sensors or microcontroller to perform the operating function of motors and pumps. STM based power inverter is efficient, less cost and reliable. My thesis work was based on STM motor drives and control system which can be implemented in a gas analyser for operating the pumps and motors. It has been widely applied in various engineering sectors due to its ability to respond to adverse structural changes and improved structural reliability. The present research was designed to use STM Inverter board on low power MCU such as NUCLEO with some practical examples such as Blinking LED, and PWM. Then we have implemented a three phase Inverter model with Steval-IPM08B board, which converter single phase 230V AC input to three phase 380 V AC output, the output will be useful for operating the induction motor.

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Web is constantly evolving, thanks to the 2.0 transition, HTML5 new features and the coming of cloud-computing, the gap between Web and traditional desktop applications is tailing off. Web-apps are more and more widespread and bring several benefits compared to traditional ones. On the other hand reference technologies, JavaScript primarly, are not keeping pace, so a paradim shift is taking place in Web programming, and so many new languages and technologies are coming out. First objective of this thesis is to survey the reference and state-of-art technologies for client-side Web programming focusing in particular on what concerns concurrency and asynchronous programming. Taking into account the problems that affect existing technologies, we finally design simpAL-web, an innovative approach to tackle Web-apps development, based on the Agent-oriented programming abstraction and the simpAL language. == Versione in italiano: Il Web è in continua evoluzione, grazie alla transizione verso il 2.0, alle nuove funzionalità introdotte con HTML5 ed all’avvento del cloud-computing, il divario tra le applicazioni Web e quelle desktop tradizionali va assottigliandosi. Le Web-apps sono sempre più diffuse e presentano diversi vantaggi rispetto a quelle tradizionali. D’altra parte le tecnologie di riferimento, JavaScript in primis, non stanno tenendo il passo, motivo per cui la programmazione Web sta andando incontro ad un cambio di paradigma e nuovi linguaggi e tecnologie stanno spuntando sempre più numerosi. Primo obiettivo di questa tesi è di passare al vaglio le tecnologie di riferimento ed allo stato dell’arte per quel che riguarda la programmmazione Web client-side, porgendo particolare attenzione agli aspetti inerenti la concorrenza e la programmazione asincrona. Considerando i principali problemi di cui soffrono le attuali tecnologie passeremo infine alla progettazione di simpAL-web, un approccio innovativo con cui affrontare lo sviluppo di Web-apps basato sulla programmazione orientata agli Agenti e sul linguaggio simpAL.

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Laser Shock Peening (LSP) is a surface enhancement treatment which induces a significant layer of beneficial compressive residual stresses of up to several mm underneath the surface of metal components in order to improve the detrimental effects of the crack growth behavior rate in it. The aim of this thesis is to predict the crack growth behavior in metallic specimens with one or more stripes which define the compressive residual stress area induced by the Laser Shock Peening treatment. The process was applied as crack retardation stripes perpendicular to the crack propagation direction with the object of slowing down the crack when approaching the peened stripes. The finite element method has been applied to simulate the redistribution of stresses in a cracked model when it is subjected to a tension load and to a compressive residual stress field, and to evaluate the Stress Intensity Factor (SIF) in this condition. Finally, the Afgrow software is used to predict the crack growth behavior of the component following the Laser Shock Peening treatment and to detect the improvement in the fatigue life comparing it to the baseline specimen. An educational internship at the “Research & Technologies Germany – Hamburg” department of AIRBUS helped to achieve knowledge and experience to write this thesis. The main tasks of the thesis are the following: •To up to date Literature Survey related to “Laser Shock Peening in Metallic Structures” •To validate the FE model developed against experimental measurements at coupon level •To develop design of crack growth slowdown in Centered Cracked Tension specimens based on residual stress engineering approach using laser peened strip transversal to the crack path •To evaluate the Stress Intensity Factor values for Centered Cracked Tension specimens after the Laser Shock Peening treatment via Finite Element Analysis •To predict the crack growth behavior in Centered Cracked Tension specimens using as input the SIF values evaluated with the FE simulations •To validate the results by means of experimental tests

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Conventional inorganic materials for x-ray radiation sensors suffer from several drawbacks, including their inability to cover large curved areas, me- chanical sti ffness, lack of tissue-equivalence and toxicity. Semiconducting organic polymers represent an alternative and have been employed as di- rect photoconversion material in organic diodes. In contrast to inorganic detector materials, polymers allow low-cost and large area fabrication by sol- vent based methods. In addition their processing is compliant with fexible low-temperature substrates. Flexible and large-area detectors are needed for dosimetry in medical radiotherapy and security applications. The objective of my thesis is to achieve optimized organic polymer diodes for fexible, di- rect x-ray detectors. To this end polymer diodes based on two different semi- conducting polymers, polyvinylcarbazole (PVK) and poly(9,9-dioctyluorene) (PFO) have been fabricated. The diodes show state-of-the-art rectifying be- haviour and hole transport mobilities comparable to reference materials. In order to improve the X-ray stopping power, high-Z nanoparticle Bi2O3 or WO3 where added to realize a polymer-nanoparticle composite with opti- mized properities. X-ray detector characterization resulted in sensitivties of up to 14 uC/Gy/cm2 for PVK when diodes were operated in reverse. Addition of nanoparticles could further improve the performance and a maximum sensitivy of 19 uC/Gy/cm2 was obtained for the PFO diodes. Compared to the pure PFO diode this corresponds to a five-fold increase and thus highlights the potentiality of nanoparticles for polymer detector design. In- terestingly the pure polymer diodes showed an order of magnitude increase in sensitivity when operated in forward regime. The increase was attributed to a different detection mechanism based on the modulation of the diodes conductivity.

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This master thesis proposes a solution to the approach problem in case of unknown severe microburst wind shear for a fixed-wing aircraft, accounting for both longitudinal and lateral dynamics. The adaptive controller design for wind rejection is also addressed, exploiting the wind estimation provided by suitable estimators. It is able to successfully complete the final approach phase even in presence of wind shear, and at the same time aerodynamic envelope protection is retained. The adaptive controller for wind compensation has been designed by a backstepping approach and feedback linearization for time-varying systems. The wind shear components have been estimated by higher-order sliding mode schemes. At the end of this work the results are provided, an autonomous final approach in presence of microburst is discussed, performances are analyzed, and estimation of the microburst characteristics from telemetry data is examined.

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Due to the low cost, lightness and flexibility, Polymer Solar Cell (PSC) technology is considered one of the most promising energy technologies. In the past decades, PSCs using fullerenes or fullerene derivatives as the electron acceptors have made great progress with best power conversion efficiency (PCE) reaching 11%. However, fullerene type electron acceptors have several drawbacks such as complicated synthesis, a low light absorption coefficient and poor tuning in energy levels, which prevent the further development of fullerene-based PSCs. Hence the need to have a new class of electron acceptors as an alternative to conventional fullerene compounds. Non-fullerene acceptors (NFAs) have developed rapidly in the last years and the maximum PCEs have exceeded 14% for single-junction cells and 17% for double-junction tandem cells. By combining an electron-donating backbone, generally with several fused rings with electron-withdrawing units, we can simply construct NFA of the acceptor–donor–acceptor type (A–D–A). Versatile molecular structures have been developed using methods such as acceptor motif engineering and donor motif engineering. However, there are only a few electron-donating backbones that have been proved to be successful. Therefore, it is still necessary to develop promising building blocks to further enrich the structural diversity. An indacenodithiophene (IDT) unit with just five fused rings has a sufficiently rigid coplanar structure, which has been regarded as one of the promising electron-rich units to design high-performance A–D–A NFAs. In this work, performed at the King Abdullah University of Science and Technology in Saudi Arabia, a new nine-cyclic building block (TBIDT) with a two benzothiophene unit was synthesized and used for designing new non-fullerene electron acceptors.

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In this thesis work, a cosmic-ray telescope was set up in the INFN laboratories in Bologna using smaller size replicas of CMS Drift Tubes chambers, called MiniDTs, to test and develop new electronics for the CMS Phase-2 upgrade. The MiniDTs were assembled in INFN National Laboratory in Legnaro, Italy. Scintillator tiles complete the telescope, providing a signal independent of the MiniDTs for offline analysis. The telescope readout is a test system for the CMS Phase-2 upgrade data acquisition design. The readout is based on the early prototype of a radiation-hard FPGA-based board developed for the High Luminosity LHC CMS upgrade, called On Board electronics for Drift Tubes. Once the set-up was operational, we developed an online monitor to display in real-time the most important observables to check the quality of the data acquisition. We performed an offline analysis of the collected data using a custom version of CMS software tools, which allowed us to estimate the time pedestal and drift velocity in each chamber, evaluate the efficiency of the different DT cells, and measure the space and time resolution of the telescope system.

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Recent years have witnessed an increasing evolution of wireless mobile networks, with an intensive research work aimed at developing new efficient techniques for the future 6G standards. In the framework of massive machine-type communication (mMTC), emerging Internet of Things (IoT) applications, in which sensor nodes and smart devices transmit unpredictably and sporadically short data packets without coordination, are gaining an increasing interest. In this work, new medium access control (MAC) protocols for massive IoT, capable of supporting a non-instantaneous feedback from the receiver, are studied. These schemes guarantee an high time for the acknowledgment (ACK) messages to the base station (BS), without a significant performance loss. Then, an error floor analysis of the considered protocols is performed in order to obtain useful guidelines for the system design. Furthermore, non-orthogonal multiple access (NOMA) coded random access (CRA) schemes based on power domain are here developed. The introduction of power diversity permits to solve more packet collision at the physical (PHY) layer, with an important reduction of the packet loss rate (PLR) in comparison to the number of active users in the system. The proposed solutions aim to improve the actual grant-free protocols, respecting the stringent constraints of scalability, reliability and latency requested by 6G networks.