Dissertations / Theses on the topic 'Calibratori'

I calibratori di attività dei radionuclidi sono strumenti fondamentali per la pratica diagnostica e terapeutica in Medicina Nucleare. Il loro ruolo principale è quello di quantificare accuratamente l’attività dei radiofarmaci somministrata ai pazienti, vengono pertanto progettati per avere una accuratezza di misura ottimale per attività relativamente alte. Lo scopo di questo studio è stato quello di determinare il livello di minima attività rivelabile (o Minimum Detectable Activity, MDA) di diversi modelli di calibratori di attività, al fine di estendere l’utilizzo di questi strumenti ad altre applicazioni. E’ stata quindi eseguita un’estesa campagna di misure sperimentali sui principali modelli di calibratori commercialmente distribuiti. Le modalità di misura della MDA sviluppate sono basate su un adattamento delle tecniche di riferimento per altri tipi di strumenti; tali tecniche, non solo rispondono all’obiettivo immediato, ma hanno permesso di dimostrare che è possibile una determinazione generalizzata della MDA di questa classe di apparecchiature. I risultati che verranno presentati sono stati ottenuti con una metodologia indipendente dal tipo di apparecchiatura e sono basati su misurazioni che possono essere replicate in ogni laboratorio.

I calibratori di attività sono strumenti molto importanti per la pratica, diagnostica e terapeutica, in medicina nucleare, perché permettono di associare ad un radiofarmaco una misura accurata dell’attività dell’isotopo in esso contenuto; questo è fondamentale in quanto l’attività della sorgente esprime la quantità di farmaco somministrata al paziente. In questo lavoro è stato sviluppato il modello Monte Carlo di un calibratore di attività ampiamente diffuso nei laboratori di radiofarmacia (Capintec CRC-15), utilizzando il codice Monte Carlo FLUKA. Per realizzare il modello si è posta estrema attenzione nel riprodurre al meglio tutti i dettagli delle componenti geometriche della camera e dei campioni delle sorgenti radioattive utilizzati. A tale scopo, la camera di ionizzazione di un calibratore è stata studiata mediante imaging TAC. Un’analisi preliminare è stata eseguita valutando il confronto tra l’andamento sperimentale dell’efficienza della camera in funzione dell’energia dei fotoni incidenti e quello ottenuto in simulazione. In seguito si è proceduto con la validazione: si sono studiati a questo proposito la risposta del calibratore in funzione dell’altezza della sorgente e i confronti tra i fattori relativi (rispetto ad una sorgente certificata di 137Cs) e le misure di confronto sono state eseguite con diverse sorgenti certificate di 133Ba, 68Ge-68Ga, 177Lu ed uno standard tarato internamente di 99mTc. In tale modo, si è ricoperto l'intero campo di interesse dei principali radionuclidi impiegati nelle applicazioni diagnostiche e terapeutiche di Medicina Nucleare. Il modello sviluppato rappresenta un importante risultato per l’eventuale determinazione di nuovi fattori di calibrazione o per un futuro studio relativo all’ottimizzazione della risposta del calibratore.

Questo elaborato consiste nello sviluppo di una piccola galleria del vento a ciclo aperto finalizzata alla calibrazione di anemometri a filo caldo da impiegare negli ambienti del CICLoPE (Centre for International Cooperation in Long Pipe Experiments) dell'Università di Bologna. La necessità di un dispositivo siffatto nasce dall'impossibilità di calibrare correttamente le sonde nella sezione di test del laboratorio in quanto subentrano effetti perturbativi legati all'instabilità e non-uniformità del flusso. Per ovviare al problema è possibile sfruttare la regione potenziale di un getto libero. In questo caso l'apparecchiatura è stata ideata per generare un getto piano rettangolare in grado di consentire la calibrazione di più anemometri contemporaneamente. Caratteristica principale del dispositivo è quella di essere modulare, così da renderlo versatile e facile da mantenere e pulire. La fase concettuale del progetto è seguita dalla stima delle perdite di carico indotte dai componenti, necessaria alla selezione di un ventilatore centrifugo capace di sostentare il flusso d'aria.

Il presente elaborato propone un metodo di calibrazione alle basse velocità degli anemometri a filo caldo utilizzati nella galleria del vento presente al C.I.C.Lo.P.E. (Center for International Cooperation in Long Pipe Experiments) dell'Università di Bologna, potenzialmente estendibile ad applicazioni più generali. In seguito ad un'analisi teorica approfondita della fattibilità di una calibrazione alle basse velocità, si è dimensionato e realizzato un prototipo in P.V.C. a geometria convergente-divergente, ritenuto in grado di produrre un flusso uniforme in uscita tale da garantire una soluzione al problema della calibrazione all'interno della test-section della galleria. Completata la fabbricazione del componente si è condotta un'analisi sperimentale, con l'ausilio del C.A.T. (Coaxial Air Tunnel) presente nell'hangar della Scuola di Ingegneria, sede di Forlì, del flusso generato internamente al divergente del calibratore. Nonostante si sia rilevata, mediante lo studio sperimentale condotto, una non perfetta uniformità del flusso uscente dal componente, i risultati riscontrati hanno permesso di inquadrare approcci e soluzioni atti ad un'ottimizzazione del calibratore, lasciando ampio margine di miglioramento ai fini della calibrazione alle basse velocità mediante il metodo descritto.

This thesis presents a study of potential calibrators observed by the Karoo Array Telescope (KAT-7). The KAT-7 is an engineering prototype for the coming sensitive array, the MeerKAT, one of the pathfinders for the Square Kilometre Array (SKA). This thesis plays a supporting role in the ongoing commissioning activities of the KAT-7, whose construction started in early 2008, and which has been undergoing engineering and science verifications since late 2010. This thesis has achieved the first steps towards identifying possible flux-density standards for short baseline interferometers such as the KAT-7. The systematic error for flux-density calibration at KAT-7 was estimated relative to 3C123, and it was found to be ~5% of the measured flux density. 18 (~47%) of the 38 sources were identified as good flux density calibrator candidates, for their Modulation Index (MI) and Variability Index (VI) values were less than 0.05 and all the sources in the field had less than 10% of the peak flux density of the calibrator candidate. One source (PKS J0837-1951), which showed low variability and hence appeared to be a good flux-density calibrator candidate (class A), was deemed to be not a good flux-density calibrator candidate because a strong confusing source was found within its primary beam. Eight sources had MI or VI values between 0.05 and 0.09 and may deserve further study as potential flux calibrator candidates. Five sources had MI or VI values greater than 0.09 suggesting significant variability while 17 sources had only one or two observations so their suitability as potential flux calibrator candidates could not be evaluated. In addition, we used another measure of variability, the de-biased modulation index, for our sources comparing the observed modulation indices against Monte Carlo simulations. The result showed that the values of Md are largely as expected and the uncertainties therefore not substantially underestimated.

A grandeza produto kerma-área (PKA) é importante para estabelecer níveis de referência em exames de radiologia diagnóstica. Essa grandeza pode ser obtida por meio de medidores do PKA. O uso desses medidores é fundamental para avaliar a dose de radiação em procedimentos radiológicos, além de ser um bom indicador para que os limites de dose na pele do paciente não sejam excedidos. Algumas vezes, esses medidores vêm acoplados a equipamentos de radiação X, o que dificulta sua calibração. Neste trabalho foi desenvolvida uma metodologia de calibração de medidores do PKA. O instrumento utilizado para este fim foi o Patient Dose Calibrator (PDC). Ele foi desenvolvido para ser utilizado como referência na verificação da calibração de medidores do PKA e kerma no ar usados na dosimetria de pacientes e para verificação da consistência e do comportamento de sistemas de controle de exposição automáticos. Por se tratar de um equipamento novo, que, no Brasil, ainda não é utilizado como equipamento de referência para calibração, foi realizado, também o controle de qualidade deste equipamento, com testes de caracterização, a calibração e a avaliação da dependência energética. Após os testes, ficou provado que o PDC pode ser utilizado como instrumento de referência para a calibração a ser realizada in situ, de forma que as características de cada equipamento de radiação X onde os medidores do PKA são utilizados sejam consideradas. A calibração foi, então, realizada com medidores do PKA portáteis e em um equipamento de radiologia intervencionista que possui um medidor do PKA acoplado. Os resultados foram bons e ficou provada a necessidade de calibração desses medidores e a importância da calibração in situ com um medidor de referência.
The quantity kerma area product (PKA) is important to establish reference levels in diagnostic radiology exams. This quantity can be obtained using a PKA meter. The use of such meters is essential to evaluate the radiation dose in radiological procedures and is a good indicator to make sure that the dose limit to the patient\'s skin doesnt exceed. Sometimes, these meters come fixed to X radiation equipment, which makes its calibration difficult. In this work, it was developed a methodology for calibration of PKA meters. The instrument used for this purpose was the Patient Dose Calibrator (PDC). It was developed to be used as a reference to check the calibration of PKA and air kerma meters that are used for dosimetry in patients and to verify the consistency and behavior of systems of automatic exposure control. Because it is a new equipment, which, in Brazil, is not yet used as reference equipment for calibration, it was also performed the quality control of this equipment with characterization tests, the calibration and an evaluation of the energy dependence. After the tests, it was proved that the PDC can be used as a reference instrument and that the calibration must be performed in situ, so that the characteristics of each X-ray equipment, where the PKA meters are used, are considered. The calibration was then performed with portable PKA meters and in an interventional radiology equipment that has a PKA meter fixed. The results were good and it was proved the need for calibration of these meters and the importance of in situ calibration with a reference meter.

I calibratori di attività sono strumenti fondamentali in medicina nucleare, utilizzati da ogni struttura al fine di quantificare l’attività di radiofarmaco da somministrare al paziente. L'accurata taratura di questi strumenti richiederebbe la disponibilità di sorgenti di riferimento certificate per ciascun radionuclide di interesse; tuttavia vi è una importante serie di casi in cui questo metodo non è praticabile a causa delle caratteristiche del radionuclide, come ad esempio il brevissimo tempo di dimezzamento. Lo scopo di questo studio è stato determinare il fattore di taratura per un radioisotopo PET a brevissimo tempo di dimezzamento, il 11C, per il quale non sono commercialmente reperibili delle sorgenti certificate, eseguendo un’accurata misura dell’efficienza di rivelazione di un moderno rivelatore per spettrometria allo specifico valore di energia di 511 keV dei fotoni di annichilazione. Lo strumento utilizzato è un nuovo rivelatore a CZT (tellururo di cadmio-zinco), il Kromek GR1, un rivelatore compatto che opera a temperatura ambiente, caratterizzato da una interessante risoluzione energetica e da una efficienza di rivelazione contenuta, quest’ultima adeguata per l’analisi di campioni che hanno un’attività relativamente elevata, come di frequente accade nei siti di produzione dei nuclidi radioattivi. Le misure sperimentali sono state eseguite cercando di ottimizzare ogni passaggio al fine di minimizzare le incertezze, in modo da ottenere una stima accurata del fattore di taratura, secondo una modalità tracciabile ad uno standard accreditato NIST e riproducibile per qualunque altro radioisotopo PET. Potranno quindi essere constatati i fattori di taratura noti di altri radionuclidi e successivamente stimati i fattori per radioisotopi sperimentali anche mediante diversi modelli di calibratori.

Dynamic mechanical analysis (DMA) is the most preferred thermal analysis technique for determining the glass transition temperature (Tg) of polymer matrix composites because it is more sensitive to Tg measurements than other thermal analysis techniques. An interlaboratory study was developed and conducted by the American Society for Testing and Materials (ASTM) for its D7028-07 test standard (Tg by DMA). The results of the study indicated that reproducibility was poor between DMA instruments and laboratories. A reproducibility standard deviation of 15.09 degree F and 14.72 degree F for dry Tg and wet Tg measurements, respectively, was found. Poor reproducibility of Tg measurements creates uncertainty in cases where Tg measurements are utilized. Service temperature and process control determinations may be difficult to establish if reproducibility of Tg measurements remains poor. The goal of this research was to improve laboratory-to-laboratory and instrument-to-instrument reproducibility. To accomplish this, several potential influencers of Tg measurements, such as, thermocouple positioning, dimensional variation of specimens, and temperature calibration configurations and methods were evaluated. These evaluations were the framework to the development of thermocouple guidelines and temperature calibration procedures to aid test operators in areas where the test and calibration standards are not specific. To assess whether this goal was achieved, a follow-on interlaboratory study was conducted. A reproducibility standard deviation of 7.86 degree F and 7.30 degree F for dry Tg and wet Tg measurements, respectively, was determined. When compared with the interlaboratory study conducted by ASTM, the follow-on interlaboratory study indicated a 50% improvement in the reproducibility of Tg measurements was achieved with the implementation of the developed thermocouple guidelines and temperature calibration procedures.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering

Detailed knowledge of solar-type stars is essential in the understanding of the evolutionary past, presence and future of the Sun as well as the formation of its planetary system. Moreover, solar-type stars are of key significance for the study of the evolution of the Galaxy. The ages of solar-type stars map the full galactic evolution. Their surface layers are well mixed and just little affected by the interior nuclear processes. They may therefore be used as samples of the gas from which the stars were once formed. Models of stellar atmospheres are used to derive fundamental stellar quantities such as chemical composition, effective temperature, surface gravity, age and rotation. It is therefore also important to investigate the progress and shortcomings of the atmospheric models and the reliability of calibrations based upon these. In this thesis we explore the potential of synthetic uvbyHβ colours for deriving atmospheric parameters. The theoretical colours are derived using high-resolution synthetic spectra based on 1D atmosphere models of late-type stars. Furthermore, possible applications of the established synthetic colours on globular stellar clusters are tested. Observations of solar-type stars have demonstrated the existence of stars very similar to the Sun, so-called solar twins. A detailed chemical analysis of these stars, however, shows that most solar-twins are systematically richer, as compared with the Sun, in refractory elements such as Fe, Ni and Al, relative to volatile elements like C, N and O. This chemical abundance pattern has been suggested to be related to the formation of planets or the birth environment of the respective star. In this thesis we present a high-accuracy study on a solar-twin star in the old open cluster M67. We find that the star is very similar to the Sun when comparing their atmospheric parameters, effective temperature, surface gravity and metallicity. Remarkably enough, unlike most solar twins observed in the solar vicinity, the cluster twin shows the same refractory to volatile pattern as the Sun.The reason for this similarity is still unknown but further observations of the cluster will help to clarify the matter. M dwarfs constitute a large fraction of the detectable baryonic matter. In spite of this, detailed knowledge on the numerous neighbouring low-mass stars is still not available. The presence of strong molecular features in the spectra, and incomplete line lists for the corresponding molecules have made metallicity determinations of M dwarfs difficult. Furthermore, the faint M dwarfs require long exposure times for a signal-to-noise ratio sufficient for detailed spectroscopic abundance analysis. In this thesis we present a high resolution spectroscopic study of early-type M dwarfs in the infrared. The lack of prominent molecular bands in parts of the infrared J-band (1100--1400 nm) allows a precise continuum placement. Furthermore, we verify the adequacy of using the model atmospheres for abundance determination by observing a set of binary systems with a solar-type primary and an M dwarf companion. We present a reliable zero-point for the metallicity scale of early-type M dwarfs and verify the reliability of spectroscopic abundance analyses in the infrared.

La tecnologia MdP odierna risente di grosse limitazioni a causa di una inadeguata divulgazione, soprattutto a livello universitario, delle conoscenze sulle teorie dei processi e della progettazione di impianti ad essa legati. La conseguenza è l’accentramento del know-how all’interno delle aziende del settore (progettazione presse e impianti di sinterizzazione, sviluppo materie prime, progettazione stampi e cicli produttivi…) le quali, nel tempo, hanno creato al loro interno tecnici specializzati, laboratori di ricerca e sofisticati reparti R&D. Nonostante il risultato evidente oggi in Europa sia una buona preparazione tecnica da parte delle aziende operanti nel settore, la scarsa diffusione di conoscenze anche negli altri ambiti dell’ingegneria e della progettazione meccanica rende spesso difficile l’incontro tra due realtà che potrebbero invece aprire nuovi settori di produzione e/o il miglioramento di progetti noti. Questo lavoro è fondato sulla base di tali considerazioni e svolto interamente all’interno di una delle più importanti realtà industriali nazionali in questo campo: Sinteris S.p.A. (Bologna). Dopo una descrizione del processo classico, si passerà ad analizzare, tramite prove in laboratorio, il processo di calibratura di rotori pompa per circuiti lubrificanti in campo automotiv. Lo studio riguarda il rilievo e il confronto delle variazioni dimensionali ottenute a diverse percentuali di calibratura su rotori di diverse altezze (entro e oltre i limiti progettuali fino ad oggi realizzati in Sinteris) allo scopo di far luce sulle deformazioni plastiche che condizionano la conformità dei pezzi sinterizzati sottoposti a calibratura entro stampi rigidi di dimensioni note. Lo scopo ideale di questa ricerca è trovare una legge su base empirica che consenta all’Engineering di progettare stampi di calibratura e percentuali di schiacciamento che garantiscano, ad ogni montaggio, la conformità dimensionale di attuali e futuri progetti di pompe a lobi.

[EN] Neutrino astronomy is a booming field in astroparticle physics. Due to the particular characteristics of neutrinos, these particles offer great advantages as probes for the study of the far and high-energy Universe. It is extensively accepted by the scientific community that a multi-messenger approach with the combination of information provided by neutrinos, photons and charged particles (cosmic rays) is possible to obtain a more complete image of the fundamental astrophysics processes taking place in our Universe. Since neutrinos are neutral and very weak interacting particles they can reach the Earth from astrophysical sources without deflection by magnetic fields and almost without energy losses and absorption, contrarily to the rest of messengers. The other side of the coin of neutrino properties is that detection of neutrinos is very challenging and big highly instrumented detection volumes are needed. Natural media (deep sea, lakes or ice in the Antarctica) host this kind of experiments using the water (or ice) as target material where the neutrino interaction is produced. ANTARES is the first undersea neutrino telescope, located at 2475 m depth in the Mediterranean Sea. ANTARES is optimized for optical detection of the Cerenkov light induced by relativistic muons produced by high energy neutrino interactions near the detector. The charge, position and arrival time of the photons to the optical modules which compose the detector allows the muon track reconstruction, and thus, knowing the neutrino coming direction. Some information of the event energy is also derived. ANTARES is also hosting the AMADEUS experiment which is investigating the feasibility of the acoustic detection of Ultra-High Energy (UHE) neutrinos. The framework of this thesis is the ANTARES experiment. As commonly done in the thesis developed in this experiment (and in this field), the work has been divided in two different areas. On the one hand, a part more devoted to technological aspects related to the detector and, on the other hand, a part dedicated to ANTARES data analysis. The first part of the thesis is focused in the development of a calibrator able to reproduce the acoustic signal generated in the UHE neutrino interaction with a water nucleus which, roughly speaking, generates a highly directive bipolar acoustic pulse. Having a good calibrator is crucial to test and tune the telescope response for this kind of signals. The second part of the thesis, the data analysis part, is centred in the analysis of the ANTARES data in order to constrain possible Dark Matter models. This work is focused on the detection of products resulting of the Dark Matter annihilation trapped in the centre of the Sun. Specifically, the Secluded Dark Matter (SDM) model has been tested by the detection of di-muons (co-linear muon pair) and/or neutrinos coming from Sun direction. Broadly speaking, this model is based on the idea of the existence of a mediator resulting of the Dark Matter annihilation which, subsequently, would decay into standard model particles as muons or neutrinos. These models have been proposed in order to explain some experimental "anomalies" observed, such as the electron-positron ratio spectrum detected in satellites, measured recently with high accuracy by AMS-II. The study of this thesis constitutes the first search of experimental evidences of this kind of models in neutrino telescopes.
[ES] La astronomía de neutrinos es un campo en auge dentro de la Física de Astropartículas. Los neutrinos ofrecen grandes ventajas como sondas para estudiar el Universo lejano y de alta energía. Es extensamente aceptado que mediante la combinación de la información que proporcionan los neutrinos junto a la obtenida mediante fotones de alta energía (rayos gamma) y partículas cargadas (rayos cósmicos) se podría obtener una imagen más completa de los procesos astrofísicos fundamentales que tienen lugar a lo largo de nuestro Universo.La razón fundamental por la que los neutrinos son tan altamente valorados como mensajeros es la baja interacción con el medio que los rodea. Al ser partículas sin carga interactúan muy débilmente con la materia, por ello pueden escaparse de la fuente donde se han producido y, al contrario de lo que ocurre con el resto de mensajeros, pueden llegar a la Tierra sin ser desviados por los campo magnéticos y sin prácticamente pérdida de energía. Esta misma razón que los hace tan valorados es a su vez la que los hace tan difíciles de detectar. Se impone la necesidad de construir detectores de grandes volúmenes, del orden del km3, altamente instrumentados. Se utilizan medios naturales (en el fondo del mar, en lagos o en enterrados en el hielo de la Antártida) aprovechando el agua (o hielo) como material diana donde se espera que interaccione el neutrino. ANTARES es el primer telescopio submarino de neutrinos construido en el fondo del mar Mediterráneo. Está optimizado para la detección óptica de la luz Cherenkov inducida por los muones relativistas producidos en la interacción de neutrinos de alta energía en los alrededores del detector. La información de la carga, posición y tiempo de llegada de los fotones a los fotomultiplicadores que componen el detector permite tanto la reconstrucción de la trayectoria del neutrino como el conocimiento de su energía. Además, ANTARES acoge el experimento AMADEUS mediante el cual se está investigando y testeando la detección acústica de neutrinos de muy alta energía que, al interaccionar en el agua, producen un pulso termo-acústico que se pretende registrar con una red de hidrófonos. El trabajo desarrollado en esta tesis se engloba bajo el marco del experimento ANTARES. Como es común en las tesis desarrolladas en este experimento, el trabajo se ha dividido en dos áreas diferenciadas: por un lado, una parte de enfoque más tecnológico y, por otro lado, una parte analítica de datos tomados por el telescopio. La primera parte de la tesis está centrada en el desarrollo de un calibrador capaz de reproducir la señal acústica que se emite en la interacción de un neutrino de alta energía con un núcleo de agua que, generalizando, es un pulso bipolar altamente directivo. El disponer de un buen calibrador es clave a la hora de testear la detección acústica en el telescopio y poder sintonizar y "entrenar" los los receptores para este tipo de señales. La segunda parte de la tesis se ha centrado en el análisis de datos registrados por ANTARES con el fin de contrastar posibles modelos astrofísicos para la búsqueda de materia oscura. Este trabajo ha focalizado en la detección de los productos de la aniquilación de materia oscura atrapada en el centro del Sol. Se ha testeado el modelo de Secluded Dark Matter (SDM) a través de la detección de di-muones (pareja de muones co-lineales) y neutrinos en la dirección del Sol. A grandes rasgos, este modelo se basa en la idea de la existencia de un mediador resultado de la aniquilación de materia oscura que posteriormente decaería en partículas del modelo estándar como muones o neutrinos. Estos modelos han sido propuestos con el fin de explicar ciertas 'anomalías' experimentales observadas, tales como el espectro del flujo de positrones detectado en satélites, medido recientemente con gran precisión por AMS-II. realizado en esta tesis constituye la primera búsqueda de evidencias
[CAT] L'astronomia de neutrins és un camp en auge dins la Física d'Astropartícules. Els neutrins ofereixen grans avantatges com a sondes per estudiar l'Univers llunyà i d'alta energia. Es extensament acceptat que mitjançant la combinació de la informació proporcionada pels neutrins junt a la obtinguda mitjançant fotons d'alta energia (rajos gamma) i partícules carregades (rajos còsmics) es podria obtindre una imatge més completa dels processos astrofísics fonamentals que es donen al llarg del nostre Univers. La raó fonamental per la qual els neutrins són altament valorats com a missatgers és la baixa interacció amb el medi que els envolta. Al ser partícules sense càrrega interactuen molt dèbilment amb la matèria, per això poden escapar-se de la font on s'han produït i, al contrari del que ocorre amb la resta de missatgers, poden arribar a La Terra sense desviar-se pels camps electromagnètics i sense pràcticament pèrdua d'energia. Aquesta mateixa raó que els fan tan valorats és al mateix temps la que els fa tan difícil de detectar. S'imposa la necessitat de construir detectors amb grans volums de detecció, de l'ordre del km3, altament instrumentats. S'utilitzen medis naturals (al fons de la mar, en llacs, al gel de l'Antàrtida) aprofitant l'aigua (o el gel) com a material diana on interaccionen el neutrins. ANTARES és el primer telescopi submarí de neutrins construït al fons de la mar Mediterrània. Està optimitzat per a la detecció òptica de la llum de Cherenkov induïda pels muons relativistes produïts en la interacció de neutrins d'alta energia als voltants del detector. La informació de la carrega, posició i temps d'arribada dels fotons als fotomultiplicadors que composen el detector permet tant la reconstrucció de la trajectòria del neutrí, amb gran resolució angular, com el coneixement de la seua energia. A més, ANTARES acull l'experiment AMADEUS mitjançant el qual s'està investigant i testejant la detecció acústica de neutrins de molt alta energia, que, al interaccionar a l'aigua produeixen un pols termo-acústic que es pretén registrar amb una xarxa d'hidròfons. El treball dut a terme en esta tesi s'engloba baix el marc de l'experiment ANTARES. Com es comú en les tesis desenvolupades en aquest experiment, el treball s'ha dividit en dues àrees diferenciades: per una banda una part d'enfocament mes tecnològic i, d'altra banda, una part analítica de les dades preses pel telescopi. La primera part de la tesi està centrada en el desenvolupament d'un calibrador capaç de reproduir la senyal acústica que es genera en la interacció d'un neutrí d'alta energia amb un nucli de l'aigua que, generalitzant, és un pols bipolar altament directiu. Disposar d'un bon calibrador es clau a l'hora de testejar la detecció acústica al telescopi i poder sintonitzar i "entrenar" els receptors a aquest tipus de senyals. La segona part de la tesi, amb caràcter d'anàlisi de dades, s'ha centrat en l'anàlisi de les dades registrades per ANTARES amb el fi de contrastar possibles models astrofísics per a la recerca de matèria fosca. Aquest treball es centra en la detecció dels productes d'aniquilació de matèria fosca atrapada al centre del Sol. En concret, s'ha testejat el model de Secluded Dark Matter (SDM) a través de la detecció de di-muons (parell de muons co-lineals) i neutrins en la direcció del Sol. A grans trets, aquest model es basa en la idea de l'existència d'un mediador resultat de l'aniquilació de matèria fosca que posteriorment decauria en partícules del model estàndard com muons o neutrins. Aquests models han sigut proposats amb la fi d'explicar certes "anomalies" experimentals observades, tals com l'espectre del flux de positrons detectat en satèl¿lits, mesurat recentment amb gran precisió per AMS-II. L'estudi realitzat en esta tesi constitueix la primera recerca d'evidències experimentals d'aquest tipus de models en telescopis de neutrins.
Adrián Martínez, S. (2015). Design and Development of an Acoustic Calibrator for Deep-Sea Neutrino Telescopes and First Search for Secluded Dark Matter with ANTARES [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48877
TESIS

Orientador: Ulisses Rocha Antuniassi
Banca: Paulo Roberto Arbex Silva
Banca: Kléber Pereira Lanças
Banca: Marco Antonio Gandolfo
Banca: Otavio Jorge Grigoli Abi Saab
Resumo: Os objetivos deste trabalho foram analisar os erros dos métodos usuais de calibração dos pulverizadores e quantificar o impacto econômico de problemas detectados na inspeção periódica de pulverizadores nas principais regiões produtoras de grãos no Brasil. A base do trabalho envolveu uma coleta de dados nos moldes do projeto IPP (Inspeção Periódica de Pulverizadores), englobando estudos dos equipamentos de pulverização de propriedades rurais nos Estados do Paraná (PR), Rio Grande do Sul (RS), Mato Grosso do Sul (MS) e Mato Grosso (MT). De posse da base de dados foram desenvolvidos modelos de simulação para avaliação dos métodos de calibração, estimativa de erros e dos prejuízos causados pelos mesmos. Os resultados mostraram que todas as máquinas apresentaram falhas de manutenção e calibração, com destaques para problemas no estado e conservação das pontas de pulverização. No MT 82,4% das pontas de pulverização encontravam-se inadequadas para o uso, seguido de PR com 72,5%, MS com 62,5% e RS 59,3%. Os erros na taxa de aplicação foram significativos, com valores de 70,6% para o PR, 60,2% para o RS, 37,5% para o MS e 61,8% para o MT. No que se refere ao método de calibração, o módulo dos erros médios de leitura do copo calibrador variaram de 1,8% (RS) a 2,7% (PR), enquanto o módulo dos erros médios de calibração do sensor de fluxo dos computadores variou de 5,3% (RS) a 8,8% (MT). A maior freqüência de prejuízos devido a erros de calibração da taxa de aplicação ficou na faixa de R$ 4.000,00 por ano por pulverizador. Entretanto, os fatores ligados a calibração geraram perdas maiores que R$ 10.000,00 por pulverizador por ano em alguns casos. Os problemas de manutenção também causam prejuízos, com grande freqüência de valores até R$ 4.000,00 por ano por pulverizador. De acordo com os resultados obtidos nas coletas de dados e nas simulações... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The aim of this study was to analyze errors on the sprayer calibration process and to quantify the economic impact of problems detected on periodic inspection of crop sprayers on the main soybean production regions in Brazil. This work was based on the IPP Project (Periodic Inspection of Sprayers) with focus on sprayers used on the States of Paraná (PR), Rio Grande do Sul (RS), Mato Grosso do Sul (MS) e Mato Grosso (MT). After the data collection process, some models were developed in order to analyze the calibration methods and the economic losses related to it. The results showed that all the sprayers presented failures, with emphasis on nozzle problems (82.4% on MT, 72.5% on PR, 62.5% on MS and 59.3% on RS). The frequency of errors on spray volume calibration were 70.6% on PR, 60.2% on RS, 37.5% on MS and 61,8% on MT. On the calibration process, the absolute mean errors on using the measuring cylinder range were 1.8% (RS) to 2.7% (PR), while the absolute mean errors for the calibration of the flow sensor range were 5.3% (RS) to 8,8% (MT). The higher frequency of economic losses related to the calibration process was within R$ 4,000.00 per year per sprayer. However, this value was found higher that R$ 10,000.00 per year per sprayer in some cases. Problems related to maintenance caused losses frequently up to R$ 4,000.00 per year per sprayer. Based on the data collected and the simulation using the models it was concluded that the calibration process based on the measuring cylinder present errors both related to the visual use of it the and the variability of nozzle flow along the boom. The calibration of the sprayers with electronic control showed errors above to those found on the measuring cylinder calibration process and this may be due to a chain of errors that should be further studied. As a general view the calibration process based on the measuring cylinder shower errors that... (Complete abstract click electronic access below)
Doutor

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Os objetivos deste trabalho foram analisar os erros dos métodos usuais de calibração dos pulverizadores e quantificar o impacto econômico de problemas detectados na inspeção periódica de pulverizadores nas principais regiões produtoras de grãos no Brasil. A base do trabalho envolveu uma coleta de dados nos moldes do projeto IPP (Inspeção Periódica de Pulverizadores), englobando estudos dos equipamentos de pulverização de propriedades rurais nos Estados do Paraná (PR), Rio Grande do Sul (RS), Mato Grosso do Sul (MS) e Mato Grosso (MT). De posse da base de dados foram desenvolvidos modelos de simulação para avaliação dos métodos de calibração, estimativa de erros e dos prejuízos causados pelos mesmos. Os resultados mostraram que todas as máquinas apresentaram falhas de manutenção e calibração, com destaques para problemas no estado e conservação das pontas de pulverização. No MT 82,4% das pontas de pulverização encontravam-se inadequadas para o uso, seguido de PR com 72,5%, MS com 62,5% e RS 59,3%. Os erros na taxa de aplicação foram significativos, com valores de 70,6% para o PR, 60,2% para o RS, 37,5% para o MS e 61,8% para o MT. No que se refere ao método de calibração, o módulo dos erros médios de leitura do copo calibrador variaram de 1,8% (RS) a 2,7% (PR), enquanto o módulo dos erros médios de calibração do sensor de fluxo dos computadores variou de 5,3% (RS) a 8,8% (MT). A maior freqüência de prejuízos devido a erros de calibração da taxa de aplicação ficou na faixa de R$ 4.000,00 por ano por pulverizador. Entretanto, os fatores ligados a calibração geraram perdas maiores que R$ 10.000,00 por pulverizador por ano em alguns casos. Os problemas de manutenção também causam prejuízos, com grande freqüência de valores até R$ 4.000,00 por ano por pulverizador. De acordo com os resultados obtidos nas coletas de dados e nas simulações...
The aim of this study was to analyze errors on the sprayer calibration process and to quantify the economic impact of problems detected on periodic inspection of crop sprayers on the main soybean production regions in Brazil. This work was based on the IPP Project (Periodic Inspection of Sprayers) with focus on sprayers used on the States of Paraná (PR), Rio Grande do Sul (RS), Mato Grosso do Sul (MS) e Mato Grosso (MT). After the data collection process, some models were developed in order to analyze the calibration methods and the economic losses related to it. The results showed that all the sprayers presented failures, with emphasis on nozzle problems (82.4% on MT, 72.5% on PR, 62.5% on MS and 59.3% on RS). The frequency of errors on spray volume calibration were 70.6% on PR, 60.2% on RS, 37.5% on MS and 61,8% on MT. On the calibration process, the absolute mean errors on using the measuring cylinder range were 1.8% (RS) to 2.7% (PR), while the absolute mean errors for the calibration of the flow sensor range were 5.3% (RS) to 8,8% (MT). The higher frequency of economic losses related to the calibration process was within R$ 4,000.00 per year per sprayer. However, this value was found higher that R$ 10,000.00 per year per sprayer in some cases. Problems related to maintenance caused losses frequently up to R$ 4,000.00 per year per sprayer. Based on the data collected and the simulation using the models it was concluded that the calibration process based on the measuring cylinder present errors both related to the visual use of it the and the variability of nozzle flow along the boom. The calibration of the sprayers with electronic control showed errors above to those found on the measuring cylinder calibration process and this may be due to a chain of errors that should be further studied. As a general view the calibration process based on the measuring cylinder shower errors that... (Complete abstract click electronic access below)

Spatially-resolved studies of nearby star-forming galaxies are essential to understand various physical and chemical phenomena at play in the interstellar medium in the galaxies, and consequently to obtain a comprehensive picture of galaxy formation and evolution. In this thesis, I perform spatially-resolved analyses of chemical abundances and star-formation in nearby star-forming galaxies - blue compact dwarf galaxies (BCDs) and spiral galaxies. I map various properties of H II regions and the surrounding gas within three BCDs, using integral field spectroscopic (IFS) data from the Gemini Multi-Object Spectrograph-North. While answering questions related to chemical homogeneity, ionisation mechanisms and stellar populations within BCDs, I address more profound issues, which go beyond the characterisation of studied BCDs and aim to explain global phenomena with broader implications. The BCD NGC 4449 hosts a metal-poor central star-forming region, which I explain by various scenarios related to the interplay between star-formation, metal-distribution and gas dynamics within galaxies. The BCD NGC 4670 shows an unusual negative relationship between the nitrogen-to-oxygen ratio and oxygen abundance at spatially-resolved scales. I explore this relation with chemical evolution models and by comparison to other star-forming galaxies and suggest that nitrogen enrichment, variations in star-formation efficiency or hydrodynamical effects may be responsible for the observed relation. For another BCD, SBS 1415+437, the spatially-resolved abundances on average agree with the integrated abundance, implying that low-redshift spatially-resolved results may be directly compared with unresolved high-redshift results. I study spiral galaxies to address long-standing issues related to the reliability of metallicity calibrators and the Schmidt Law of star-formation. Using IFS data of twenty-four spiral galaxies taken with the Multi-Unit Spectroscopic Explorer, I find that the current strong-line metallicity calibrators for H II regions are unsuitable for regions dominated by diffuse ionised gas (DIG). I devise new recipes for estimating the metal-content of the DIG. For another set of nine spiral galaxies, I use multi-wavelength data to show that the spatially-resolved Schmidt relation is very sensitive to the consideration of diffuse background, which is a component unrelated to the current star-formation. Removal of this component from the SFR tracers and the atomic gas results in similar local and global Schmidt relation. To conclude, the spatially-resolved analyses presented in this thesis have led to discoveries and further questions, which I will address in my ongoing and future works.

L’automazione è, negli anni, diventata un aspetto di rilievo in numerosi settori, permettendo la gestione di macchine e processi produttivi più svariati e riducendo la necessità dell’intervento umano per l’esecuzione di operazioni ripetitive e complesse. L’automazione applicata al settore ortofrutticolo ha portato allo studio di sistemi sempre più completi, in grado di semplificare la filiera che porta il prodotto dai campi di raccolta ai supermercati per la vendita; si tratta di un ambiente in cui gli standard di lavorazione diventano ogni giorno più stringenti e di alto livello grazie alle alte tecnologie ed alla grande attenzione per i dettagli. Questi standard hanno condotto alla ricerca di nuovi sistemi per la gestione della produzione, che mirano ad un raggruppamento per categorie del prodotto, il quale deve essere selezionato in relazione a considerazioni sui seguenti parametri di calibrazione: peso, diametro, colore, qualità esterna e qualità interna. Questi sistemi, per l’appunto, prendono il nome di calibratrici. Questa tesi ha lo scopo di studiare meccanicamente e costruttivamente un impianto costituito da quattro calibratrici appaiate che lavorano datteri.

The thesis deals with a problems of measuring small alternating voltage. The aim of the thesis is to explain in general problems of influences on measurement of small alternating voltage and to carry out a concrete measurement according to instructions of CMI. In the next part the thesis deals with the problems of uncertainties for measurement of small AC voltage and a concrete calculation of uncertainties has been made for measurement made in the first part of this thesis.

Riscaldamento e raffrescamento sono la principale causa del fabbisogno energetico degli edifici. Per ridurre il consumo di energia e migliorare il comfort termoigrometrico, il primo elemento su cui agire è l’involucro della costruzione. La soluzione studiata nel presente lavoro consiste in una facciata ventilata naturalmente. Per misurare l’efficacia del suddetto sistema, è stata sviluppata una simulazione energetica dinamica, validata per mezzo del confronto con i dati sperimentali acquisiti durante l’arco del 2019 su un edificio test situato a San Mauro Pascoli (FC). Oggi, nella progettazione delle costruzioni, le simulazioni energetiche rappresentano uno strumento essenziale per garantirne le prestazioni e fornire una stima accurata dei consumi e dei costi ad essi associati, data la difficoltà di rappresentazione di sistemi energetici complessi come gli edifici e i relativi impianti. Nella prima parte viene illustrato il programma di simulazione EnergyPlus, insieme ai metodi utilizzati per creare e calibrare un modello dell’edificio test. Sono stati testati e simulati vari tipi di rivestimenti esterni; i parametri scelti per il confronto tra dati simulati e misurati includono velocità e temperatura dell’aria nella cavità insieme alle temperature superficiali sul lato esterno e sul lato interno dei vari elementi della costruzione. Nella parte finale, una volta caratterizzato il comportamento energetico della facciata ventilata grazie alle simulazioni calibrate, le varie soluzioni sono applicate a un edificio esistente, anch’esso modellato attraverso EnergyPlus, al fine di operare un confronto tra i summenzionati sistemi e un tradizionale isolamento a cappotto. I risultati delle simulazioni hanno evidenziato la capacità delle strutture ventilate di ridurre i consumi energetici per il raffrescamento, a fronte di un leggero incremento della domanda per il riscaldamento, con un risparmio globale di energia su tutto l’anno rispetto all’isolamento tradizionale.

碩士
國立中央大學
遙測科技碩士學位學程
99
A tunable Doppler shift active radar calibrator (ARC) system has been developed in 2007 to produce two symmetric point targets along the SAR track [1]. It was further improved in order to generate much more frequency shift points up[2]. Because of the fixed frequency shifts and thus equal spacing on the image, it makes the site restricted in experiments, and the output power is not constant over these points. This study focuses on designing a digital Doppler shift in ARC system that produce artificial point targets at adjustable spacing and constant output power serving as control points for both geometric and radiometric calibrations. Furthermore, a combination of digital time delay and Doppler shift is simulated for feasibility study of a hybrid ARC system that generate point target on both azimuth and range direction.

博士
國立臺北科技大學
機電科技研究所
98
A hydraulic step calibrator called HS calibrator was developed for the dynamic calibration of pressure sensors. Using the spool-valve mechanism, the HS calibrator was objective to generate hydraulic step waves with the quick transient response that existing hydraulic step calibrators can not achieved yet. Like conventional function generators, the HS calibrator was then employed to excite three pressure sensors. The transfer functions of the test pressure sensors were obtained experimentally via the identification with the autoregressive exogenous model (ARX). The contact-seal mechanism was applied to seal the HS calibrator realized by the interference fit between the movable spool and the stationary housing. Moreover, a two-degree-of-freedom model was firstly introduced to describe and predict the pressure transient of the hydraulic step waves generated by the HS calibrator. The experimental results demonstrate that the developed HS calibrator successfully yields the hydraulic step wave with the short rise time. The test pressure sensors were finally described by the Bode diagram and unit-step response based on the derived transfer functions.

碩士
國立臺灣師範大學
物理學系
107
Photon calibrator (Pcal) is an independent device that can provide artificial input to an interferometric gravitational-wave detector by exerting the radiation pressure of its own laser on the test mass mirror in the interferometer. It not only can provide a fiducial length reference for calibration purpose but also can inject simulated gravitational waveforms to verify the response of the interferometer to the astrophysical gravitational waves, known as hardware injection test. Currently, the injection signals (Excitations) are produced by KAGRA Digital System(DGS). These signals change the intensity of PCal Laser by acousto-optic modulators (AOM) inside the transmitter module of PCal. However, if the output signal from the Digital System is noisy, it force AOM to modulate laser intensity according to such noisy control signal, resulting in noisy radiation force on the End Test Mirror (ETM). In this dissertation, we implemented and characterized an analog filter known as the De-Whitening filter. We installed it between Digital System output and PCal to address the noise problem while keeping the accuracy of injected signals.

碩士
國立中央大學
遙測科技碩士學位學程
98
Synthetic aperture radar(SAR) is capable of observing the changes of the earth surface in all weather. It has a great deal of the advantages to analyze and to collect the information about the environment on the earth, such as geological survey, the movement of the surface of the earth, and the ocean polluted extent, to name a few. However the precise geometric and radiometric calibrations are the critical points for SAR image processing. Our team has developed the delay line and the multiplier to produce the shift points at range direction and azimuth directions respectively. For the consideration of costs, convenience and efficiency, the focus in this study is to design a digital delay in active radar calibrator that can produce equal distance point target responses that serve as control points for both geometric and radiometric calibrations, by using FPGA. Performance of the digital ARC is tested on C-band ERS-2 SAR image. From the experimental results, the FPGA circuit can produce one to six calibration points of any time delay . In addition, the time delay error of the second-generation analog devices active radar calibrator is about 30ns to 50ns while the third one is less than 10ns. And the stability of the time delay and output power in the third one are both much better than in the second one.

碩士
國立中央大學
通訊工程研究所
92
This paper developed an Active Radar Calibrator to calibrate the C-band SAR imaging radar system, we carried out the design process of the Active Radar Calibrator (ARC) and calibration experiment of the C-band synthetic aperature radar (SAR) of both ERS-2 and ENVISAT. On I March 2002, the European Space Agency launched ENVISAT, an advanced polar-orbiting Earth observation satellite which will provide measurements of the atmosphere, ocean, land, and ice over a five year period. The ENVISAT satellite has an ambitious and innovative payload that will ensure the continuity of the data measurements of the ESA ERS satellite. The ARC is designed return both V and H radar signals with two transmission antennas and it was identified clearly including a 4 s delay and system gain(RCS=75.97dBm2) for radiometric calibration. For calibration of the C-band SAR, we have employed an ARC located in grassland near the Jhong-Ping elementary school in Chung-Li, Taiwan. We estimate the accurate azimuth and elevation angles in order to acquire the calibration constant (K) from the image data, we have examined image amplitude (date numbers) and locations of the ARC. It is seen in the SAR image, as expected, that the positions of the ARC delay points are shifted depending on the delay time.This paper describes (1) The ARC design process and laboratory measurement performed to characterize the hardware performance, with measurement of component and propagation delay. (2) the method and preliminary results of the calibration constant (K) from the image date.

碩士
大葉大學
電信工程學系碩士班
92
In the recent years, SAR（Specific Absorption Rate）has become an important issue between mobile communications and human health due to the rising development of wireless communication technologies. The measurement system mostly used the E-Probe to measure the values of SAR. However the E-Probe which we employ to perform the SAR measurement will gradually lose its precision and accuracy. Consequently, we must send it back to the original manufacturer for calibration to ensure the accuracy of the E-Probe. In view of this, in order to save the time and the huge expense of calibration, we try to research a calibration system so that we can calibrate the E-Probe ourselves in our country. In this thesis, we calibrate the SAR Probe under two circumstances. One condition is that we calibrate the probe in the air and the other is in the tissue equivalent liquid. Before we implement these two calibrations, we have to fabricate a waveguide which is at desired operating frequency. When calibrating in the air, we put the E-Probe in the center of the waveguide aperture and gradually extend it inwardly. Then we have to record the measured SAR vaules. Nevertheless, when calibrating in the tissue equivalent liquid, we put a Teflon container filled with the tissue equivalent liquid on the top of the interior of the waveguide. Then we place the E-Probe in the center of the Teflon container and rise the E-Probe from the bottom of the container slowly. The following work is to estimate and record the SAR values the E-Probe measured. Up to the present , we have finished the measurement of electric fields within the waveguide and the inner electric fields after the Teflon is added to the waveguide. In the future, we will go on calibrating the E-Probe in anechoic chamber and calibrate it after the Teflon container is filled with the tissue equivalent liquid and so on. Eventually we will aim for using numerical methods to verify the accuracy of our simulated and measured result.

碩士
國立中央大學
遙測科技碩士學位學程
101
Abstract Radiometric calibration is essential for multi-temporal SAR image change detection and quantitative remote sensing. This study focuses on developing and implementing a power-tuning active radar calibrator (ARC). The objects are: First is tuning ARC’s power for overload of critical point in SAR image. Second is that difference of ARC’s receiving signal is large at different range in airplane SAR, so we want to tune ARC’s power. Third is the power-tuning and time-delay ARC can be used to simulate radar transmitting and receiving signal in order to test and analyze the characteristic for purpose of developing a new radar system. After extensive measurements by the power-tuning ARC, the gain stability is less than 0.6dB. The differences between power-tuning RCS experimental results and theoretical values are less than 0.2dB. Hence, the new power-tuning ARC offers very precise radiometric calibration for radar system.

碩士
國立臺灣大學
電子工程學研究所
94
The multimode TRL calibration methods is known as an approach for the measurement of multi-conductor transmission line devices. The propagation constants of different modes propagating along the multi-conductor transmission line must be different when using this method. However, in general multi-port networks, the propagating constants at each port may be equal. The thru-reflection-unequal-line (TRuL) calibration method with asymmetric R calibrator for the calibration of the equal propagation constant case is proposed. Lines of unequal length are used to make the eigenvalues unequal during calibration process. This will greatly simplify the calculation. Asymmetric “R” calibrator is proposed to simplify the sign ambiguity resolution process. The measured scattering matrices of a branch line coupler on FR4 and Rogers RO4003C substrate using proposed “TRuL” calibration method shows good agreement with EM simulation.

In this study, an optimization and search technique, based on the genetic algorithms (GAs) approach, is successfully used to develop an automatic model calibrator for the UBC Watershed Model. Unlike the existing random search calibration procedure, which limits the number of simultaneously calibrated modeling parameters to groups of about three to six at a time, the new GA-based calibrator allows all modeling parameters to be simultaneously evaluated. Because of the non-linear interactions between the modeling parameters, the simultaneous evaluation of all modeling parameters is demonstrated to achieve a good model calibration efficiently and quickly. The fundamental components of GAs as inspired by the Darwinian principle of natural selection are explained in detail in order to develop a complete GA-based model calibrator. A flow chart is used to illustrate the computational implementation of the GA procedures. Why GAs can work efficiently in finding an optimal set of modeling parameter values is explained by the schema theory with mathematical proofs provided. To test the soundness of the GA code developed for the automatic calibrator of the UBC Watershed Model, two well-studied watersheds in the Province of British Columbia, Campbell River and Illecillewaet River, are used. The effects of genetic operators (crossover, niching and elitism) on GA search efficiency are individually demonstrated. To objectively determine the performance of a calibrated watershed model, the difference between the observed and simulated streamflows is statistically measured. Four statistical measures are evaluated: coefficient of linear correlation (or coefficient of determination), Nash & Sutcliffe coefficient of efficiency (e!), least squares objective function and least absolute difference objective function are introduced. GA computational experiments show that the Nash & Sutcliffe coefficient of efficiency (e!) exhibits the most consistently decreasing trend of streamflow volume error (dV/V) as the coefficient value increases. A fifth statistical measure, the modified Nash & Sutcliffe coefficient (eopt!), is also used to quantify the difference between the observed and simulated streamflow data, and ensures the optimal or near-optimal set of model parameter values found at the end of a GA search achieves both high el and low dV/V at the same time.

碩士
國立臺灣大學
電子工程學研究所
107
A multiplying delay-locked loop (MDLL) with a background coarse-frequency selector and a frequency calibrator is presented. To reduce the reference spur due to the frequency error, a frequency calibrator using a delay-calibrated SSPD is presented. The phase noise of the CP and the SSPD is not multiplied by N2. To cover a wide frequency variation, the background coarse-frequency selector is also presented. This MDLL is fabricated in 40-nm CMOS technology. The active area is 0.013mm2, and the power consumption is 5.2mW from a supply of 1V. It exhibits a root-mean-square jitter of 229fs at 2.4GHz output and the reference spur of -54.3dBc under a reference clock of 150MHz.

A presente dissertação teve como principal objetivo a execução e implementação de protocolos de Controlo de Qualidade (CQ) dos principais aparelhos dos Serviços do HPPMedicina Molecular do Porto (HPP) e da Lenitudes-Medical Center & Research (LMCR) do Grupo Lenitudes SGPS como parte integrante do sistema de Garantia de Qualidade. O CQ da instrumentação de medicina nuclear é crucial ao seu desempenho preciso e reprodutível, garantindo o funcionamento adequado, bem como a segurança dos pacientes e trabalhadores e a garantia de procedimentos corretos de diagnóstico e terapêutica. Neste sentido, foram realizados testes de rotina de CQ aos equipamentos existentes em ambos os serviços, nomeadamente aos calibradores de dose, câmaras gama e PET/TC. Numa primeira fase, avaliou-se a exatidão, a constância, a linearidade e a geometria dos calibradores de dose. Seguidamente, realizaram-se os testes de CQ das câmaras gama: teste da uniformidade, centro de rotação e resolução e linearidade espaciais. Por fim, foi analisada a qualidade de imagem de PET/TC. Os resultados obtidos foram comparados aos limites de aceitação presentes na legislação portuguesa, com as especificações dos fabricantes dos equipamentos e guidelines internacionais. A sua análise permitiu observar a coerência dos valores e o bom funcionamento dos aparelhos, assim como solicitar e executar medidas corretivas. A partir da execução dos CQ e a sua análise, foram elaborados protocolos de CQ a serem implementados em ambos os serviços. Os procedimentos são apresentados como diretrizes para futuros CQ realizados nos serviços.
The main objective of the present dissertation was to execute and implement Quality Control (QC) protocols of the main equipment of the HPP-Molecular Medicine of Porto (HPP) and the Lenitudes- Medical Center & Research (LMCR) from the Lenitudes Group SGPS as an integrative part of the Quality Guarantee system. The QC nuclear medicine instrumentation is crucial due to its precise and reproducible performance that ensures an adequate operative system, the safety of patients and professional workers and guarantees the correct diagnostic and therapeutical procedures. Hence, routine QC tests of the existing equipment were carried out in both services, specifically dose calibrators, gamma cameras and PET/CT tests. In an initial phase, the accuracy, constancy, linearity and the geometry of the dose calibrators were evaluated. Next, QC tests of the gamma cameras were performed such as uniformity tests, center of rotation and the spatial resolution and linearity. Ultimately, the quality of the PET/TC image was analyzed. The obtained results were compared to the limits accepted by the current Portuguese legislation, with the manufacturers’ specifications and international guidelines. The detection of coherent values and the good operation of the equipment were observed from the analysis of the results. Furthermore, the application and execution of corrective measures were also deduced from the results analysis. From the QC execution and its analysis, QC protocols were developed and implemented in both services. The procedures are represented as future guidelines for QC analysis in the medical services.

Tese de doutoramento em Science and Polymer Engineering and Composites
In the profile extrusion, the experience of the die designer is crucial for obtaining good results. In industry, it is quite usual the need of several experimental trials for a specific extrusion die before a balanced flow distribution is obtained. This experimental based trial-and-error procedure is time and money consuming, but, it works, and most of the profile extrusion companies rely on such method. However, the competition is forcing the industry to look for more effective procedures and the design of profile extrusion dies is not an exception. For this purpose, computer aided design seems to be a good route. Nowadays, the available computational rheology numerical codes allow the simulation of complex fluid flows. This permits the die designer to evaluate and to optimize the flow channel, without the need to have a physical die and to perform real extrusion trials. In this work, a finite volume based numerical code was developed, for the simulation of non-Newtonian (inelastic) fluid and non-isothermal flows using unstructured meshes. The developed code is able to model the forming and cooling stages of profile extrusion, and can be used to aid the design of forming tools used in the production of complex profiles. For the code verification three benchmark problems were tested: flow between parallel plates, flow around a cylinder, and the lid driven cavity flow. The code was employed to design two extrusion dies to produce complex cross section profiles: a medical catheter die and a wood plastic composite profile for decking applications. The last was experimentally validated. Simple extrusion dies used to produced L and T shaped profiles were studied in detail, allowing a better understanding of the effect of the main geometry parameters on the flow distribution. To model the cooling stage a new implicit formulation was devised, which allowed the achievement of better convergence rates and thus the reduction of the computation times. Having in mind the solution of large dimension problems, the code was parallelized using graphics processing units (GPUs). Speedups of ten times could be obtained, drastically decreasing the time required to obtain results.
No processo de extrusão de perfis, a experiência do projetista é crucial para a obtenção de bons resultados. Na indústria, é bastante usual serem necessárias várias modificações na geometria do canal de fluxo da cabeça de extrusão para a obtenção de distribuição de fluxo equilibrada. Geralmente, o procedimento é baseado num processo de tentativa-e-erro, que consome muito tempo e dinheiro, mas funciona, e muitas das empresas de extrusão utilizam esta metodologia. A concorrência tem forçando a indústria a procurar procedimentos mais eficientes, e o projeto de cabeças de extrusão não é exceção. Para este efeito, o projeto assistido por computador parece ser uma boa via. Atualmente, os códigos numéricos de reologia computacional permitem simular escoamentos de fluidos complexos. Este facto permite ao projetista avaliar e otimizar o canal de fluxo, sem a necessidade de ter, fisicamente, uma cabeça de extrusão e fazer testes experimentais. Neste trabalho foi desenvolvido um código numérico baseado no método dos volumes finitos, para a simulação de escoamentos de fluídos não-Newtonianos (inelásticos) e não isotérmicos, usando malhas não estruturadas. O código desenvolvido é capaz de modelar as etapas de extrusão e arrefecimento do perfil extrudido, e pode ser usado para auxiliar o projeto de ferramentas de extrusão empregues na produção de perfis complexos. Para verificar o código foram testados três problemas de referência: fluxo entre placas paralelas, fluxo à volta de cilindro e escoamento em cavidade bidimensional. O código foi usado no projeto de duas cabeças de extrusão para a produção de perfis de secção transversal com geometria complexa: um cateter para aplicações médicas e um perfil em madeira compósita para aplicações em pisos de áreas externas. A última foi validada experimentalmente. O desempenho de cabeças de extrusão para a produção de perfis simples, em forma de L e T, foi estudado em detalhe, permitindo compreender o efeito dos principais parâmetros geométricos na distribuição do fluxo. Para modelar o arrefecimento foi desenvolvida uma nova implementação implícita, que permitiu obter melhores taxas de convergência e consequentes reduções de tempos de cálculo. Tendo em mente a resolução de problemas de grandes dimensões, o código foi paralelizado em placas gráficas (GPUs). Com esta melhoria obtiveram-se acelerações de cálculo em cerca de dez vezes, diminuindo drasticamente os tempos necessários para efetuar as simulações.