Progettazione di algoritmi per l'elaborazione di mappe georadar su piattaforma FPGA

Questo elaborato è il frutto di una collaborazione con Tertium Technology s.r.l. iniziata già in occasione della tesi per la laurea triennale. Questa azienda ha sede a Pisa e, in quella occasione, mi fece conoscere i sistemi georadar prodotti da IDS - Ingegneria Dei Sistemi, un'altra azienda sempre del territorio. Tertium Technology si occupava, e si occupa tuttora, della produzione e dello sviluppo delle unità di acquisizione dati per questi sistemi georadar (denominate DAD). Pochi giorni dopo l'inizio della mia tesi triennale è iniziata anche la mia esperienza lavorativa presso Tertium Technology come operatore dei collaudi e del controllo qualità delle DAD, situazione che con il tempo è evoluta in termini di coinvolgimento e responsabilità occupandomi attualmente dell'intero processo produttivo. Per il progetto relativo a questa tesi è stata ovviamente coinvolta anche IDS - Ingegneria Dei Sistemi; per la definizione degli obiettivi ho partecipato a vari incontri con l'ing. Guido Manacorda di IDS Ingegneria Dei Sistemi ed il dott. Marco Consani di Tertium Technology, durante i quali sono emerse le possibili evoluzioni delle unità di acquisizione DAD attualmente in produzione. Essendo l'architettura della DAD basata su un dispositivo FPGA, è stata valutata l'opportunità di sfruttare tale dispositivo per implementare alcuni tra i principali algoritmi di elaborazione dati georadar, dotando quindi la DAD di capacità di elaborazione della quale attualmente è priva. In particolare sono stati considerati gli Algoritmi di visualizzazione e gli Algoritmi di migrazione, risultati i più interessanti rispetto allo sviluppo che interesserà in futuro i sistemi georadar IDS. In seguito il dott. Axel Penzo di Tertium Technology mi ha illustrato il funzionamento del software K2 Detector, da lui sviluppato ed attualmente utilizzato nei sistemi IDS per l'elaborazione dati georadar: l'obiettivo infatti è stato individuato nel dimostrare che grazie alla presenza del dispositivo FPGA nella DAD sarebbe stato possibile svolgere le principali elaborazioni sui dati georadar direttamente nell'unità di acquisizione DAD e non più nell'unità di elaborazione (composta da un PC sul quale è installato il software K2 Detector). L'obiettivo è stato raggiunto quando, una volta progettate le reti per l'esecuzione degli algoritmi sopracitati e descritte in VHDL, è stato dimostrato che con le simulazioni si ottengono gli stessi risultati che con il software K2 Detector, partendo dagli stessi dati georadar in ingresso. Riassumendo, l'obiettivo della presente tesi è l'implementazione all'interno di un dispositivo FPGA di alcuni algoritmi per l'elaborazione dei segnali georadar. I vantaggi ottenibili sarebbero: - Migliore utilizzo delle risorse del sistema Georadar IDS con conseguenti riduzioni del carico di lavoro dell'unità di elaborazione e dei tempi di elaborazione. - Possibilità di realizzazione di dispositivi georadar privi dell'unità di elaborazione ma dotati di interfacce uomo/macchina come ad esempio touchscreen, avvisatori acustici o luminosi, riducendo dimensioni e costi. - L'elaborazione dati all'interno della DAD consente anche la possibilità di individuare e trasmettere all'unità di elaborazione solamente le informazioni utili, con conseguente riduzione della banda necessaria alla trasmissione. Ciò consentirebbe la trasmissione dati anche in situazioni critiche nelle quali il canale di comunicazione è intrinsecamente limitato dato il contesto applicativo, come ad esempio la testa di scavo in una macchina per le trivellazioni

Study of characteristics of plasma nitriding and oxidation of superalloy IN738LC

IN738LC is a nickel base superalloy, widely used in various applications in turbine engines at high temperatures. Its oxidation and nitriding characteristics were focused in this study. Oxidation kinetics of IN738LC in dry air was studied at selected temperatures, specially chosen depending on the chemical dynamics of the alloy at such high temperatures during annealing. Isothermal oxidation in dry air was carried out at 1000°C, 1090°C, 1140°C and 1190°C. XRD results indicated an interesting onset of preferred orientation in the ã’ depleted layer in all the samples. The XPS and XRD analyses revealed the main oxide phases present in the oxide layers. Volatilization of Cr2O3 was found to be the reason for the weight loss in the superalloy. Al2O3 formed a reliable and stable oxide layer above 1100°C. Above 1140°C two different FCC solid solutions were found to be formed and the superalloy oxidized heavily and lost weight. Intensified plasma-assisted nitriding (IPAN) is one of the most widely used surface nitriding techniques. The surface of the as-received IN738LC was nitrided using this technique. Preferred orientation was observed in the samples nitrided with 0.5, 1.0 and 1.5 mA of current density. The XPS analysis showed the formation of TiN and CrN along with TiO2. Nano precipitates of TiN were observed on the ã\u27 precipitates. IPAN improved the microhardness value of the superalloy by about 70% and its wear resistance by about 10%

FPGA BASED IMPLEMENTATION OF A POSITION ESTIMATOR FOR CONTROLLING A SWITCHED RELUCTANCE MOTOR

Rotor Position information is essential in the operation of the Switched Reluctance Motor (SRM) for properly controlling its phase currents. This thesis uses Field Programmable Gate Array (FPGA) technology to implement a method to estimate the SRMs rotor position using the inverse inductance value of the SRMs phases. The estimated rotor position is given as input to the Commutator circuit, also implemented in the FPGA, to determine when torque-producing currents should be input in the SRM phase windings. The Estimator and Commutator design is coded using Verilog HDL and is simulated using Xilinx tools. This circuit is implemented on a Xilinx Virtex XCV800 FPGA system. The experimentally generated output is validated by comparing it with simulation results from a Simulink model of the Estimator. The performance of the FPGA based SRM rotor position estimator in terms of calculation time is compared to a digital signal processor (DSP) implementation of the same position estimator algorithm. It is found that the FPGA rotor position Estimator with a 5MHz clock can update its rotor position estimate every 7s compared to an update time of 50s for a TMS320C6701-150 DSP implementation using a commercial DSP board. This is a greater than 7 to one reduction in the update time

Indicadores da arquitetura poética em contextos históricos

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Biosolids affect the growth, nitrogen accumulation and nitrogen leaching of barley

Biosolids are organic fertilisers derived from treated and stabilised sewage sludge that increase soil fertility and supply nitrogen to crops over a long period, but can also increase the risk of nitrogen (N) leaching. In this work, spring barley was grown in lysimeters filled with soil amended with biosolids, and with and without mineral N fertilisation. Biomass and the N concentration and content of shoots and roots were determined at flowering and maturity, and the N remobilization was calculated during grain filling. Drainage water was collected and analysed for N leaching. Biosolids increased soil porosity and soil nitrate, and positively affected the growth and N uptake of barley. Compared to mineral fertilisers, biosolids produced 18% higher vegetative biomass and 40% higher grain yield. During grain filling, both N uptake and N remobilization were higher with biosolids, which increased the grain N content by 32%. Nitrogen loss in leachates was 1.2% of plant uptake with mineral fertilisers and 1.7% with biosolids. Thus, soil fertilisation with biosolids greatly benefits spring barley, only slightly increasing N leaching

Design and Development of a Novel Computer Vision System for Large Plant Inspections: an application in the Railway Industry.

Computer Vision is one of the emerging fields in computer science. It presents a lot of challenges, that are not so easy to deal with. In this thesis it is shown the process of design and development of a computer vision system, that is able to reconstruct the three-dimensional surface of a train. This work describes the process of analysis and design of the vision system, the process of hardware's selection in such a way to meet the requirements, and the architectural aspects in order to manage a big quantity of data that comes from the vision system. The core of this work is the development of a 3D Structured Light scanner, that is able to reconstruct the 3D Geometry of the external surface of a train. It shows the importance of the image pre-processing in order to improve the accuracy and the robustness of the reconstruction. Finally, it presents some results of the tests did, at the moment, in the laboratory

Grain legumes differ in nitrogen accumulation and remobilisation during seed filling.

n grain legumes, the N requirements of growing seeds are generally greater than biological nitrogen fixation (BNF) and soil N uptake during seed filling, so that the N previously accumulated in the vegetative tissues needs to be redistributed in order to provide N to the seeds. Chickpea, field bean, pea, and white lupin were harvested at flowering and maturity to compare the relative contribution of BNF, soil N uptake, and N remobilisation to seed N. From flowering to maturity, shoot dry weight increased in all crops by approximately 50%, root did not appreciably change, and nodule decreased by 18%. The amount of plant N increased in all crops, however in field bean (17 g m−2) it was about twice that in chickpea, pea, and lupin. The increase was entirely due to seeds, whose N content at maturity was 26 g m−2 in field bean and 16 g m−2 in chickpea, pea, and lupin. The seed N content at maturity was higher than total N accumulation during grain filling in all crops, and endogenous N previously accumulated in vegetative parts was remobilised to fulfil the N demand of filling seeds. Nitrogen remobilisation ranged from 7 g m−2 in chickpea to 9 g m−2 in field bean, and was crucial in providing N to the seeds of chickpea, pea, and lupin (half of seed N content) but it was less important in field bean (one-third). All the vegetative organs of the plants underwent N remobilisation: shoots contributed to the N supply of seeds from 58% to 85%, roots from 11% to 37%, and nodules less than 8%. Improving grain legume yield requires either reduced N remobilisation or enhanced N supply, thus, a useful strategy is to select cultivars with high post-anthesis N2 fixation or add mineral N at flowering

Monitoring and Mapping Solutions Using Sensor Nodes and Drones

Researchers are always looking for innovative ways to collect the environmental data and ease the process of data collection on the field. Advancement in sensor technologies and drones has led to easy technological access to design custom solutions even with basic electronics and technical knowledge. This paper documents, construction and working of “ITT Smart Sense”, which is a low power, easy to use and cost effective environment monitoring system using wireless sensor network that runs autonomously on battery power for an extended period of time. Along with that, a UAV based platform, titled “ITT Smart Sense Fly”, focused on environmental monitoring and scientific research and is tailored to the needs of researchers has been proposed in this paper. This platform is comprised of an autonomous unmanned aerial vehicle (UAV)/Drone with a camera sensor, an autopilot mobile app for mission planning and other required Photogrammetry tools. The drone navigates over the area of interest based on a pre-programmed flight plan and captures a series of photographs using the on-board camera. The collected image data set is processed to create orthomosaics, high resolution maps and 3D point cloud. The proposed solutions were demonstrated with three distinct case studies

Nitrogen and phosphorus accumulation and remobilization of durum wheat as affected by soil gravel content

Soil gravel content affects many soil physical properties, as well as crop yield. Little is known regarding the influence of soil gravel content on growth and nutrient uptake of durum wheat (Triticum durum Desf.). The accumulation of nitrogen and phosphorous during the vegetative and reproductive periods and the contribution of pre-anthesis assimilates to grain N and P con- tent have been evaluated in two durum wheat varieties grown on soils with 0, 10, 20 and 30% gravel content. The two varieties showed similar behaviour and the increase of soil gravel de- creased plant biomass during the entire biological cycle. Nitrogen and P concentration of all plant parts was not affected by soil gravel content, while N and P content was greatly reduced, owing to the effect on dry matter yield. Post-anthesis accumulation and remobilization of N and P were greatly reduced: the decrease from gravel-free soil to 30% gravel content was about 41 kg N ha–1 and 4 kg P ha–1 for the former and 14 kg N ha–1 and 2 kg P ha–1 for the latter. The differences in growth rate were attributed to differences in development of the root system due to the restricted soil volume