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The Forest Vegetation Simulator (FVS) is a growth and yield modeling system widely-used for predicting stand and tree-level attributes for management and planning applications in North American forests. The accuracy of FVS predictions for a range of tree and stand level attributes depends a great deal on the performance of the diameter increment model and its predictions of change in diameter at breast height (DBH) over time. To address the challenge of predicting growth in highly variable and geographically expansive forest systems, FVS was designed to include an internal calibration algorithm that makes use of growth observations, when available, from permanent inventory plots. The basic idea is that observed growth rates on a collection of remeasured trees are used to adjust or "calibrate" FVS diameter growth predictions. Therefore, DBH modeling was the focus of this investigation. Five methods were proposed for local calibration of individual tree DBH growth predictions and compared to two sets of results generated without calibration. Data from the US Forest Service's Forest Inventory and Analysis (FIA) program were used to test the methods for eleven widely-distributed forest tree species in Virginia. Two calibration approaches were based on median prediction errors from locally-observed DBH increments spanning a five year average time interval. Two were based on simple linear regression models fitted to the locally-observed prediction errors, and one method employed a mixed effects regression model with a random intercept term estimated from locally-observed DBH increments. Data witholding, specifically a leave-one-out cross-validation was used to compare results of the methods tested. Results showed that any of the calibration approaches tested in general led to improved accuracy of DBH growth predictions, with either of the median-based methods or regression based methods performing better than the random-effects-based approach. Equivalence testing showed that median or regression-based local calibration methods met error tolerances within ± 12% of observed DBH increments for all species with the random effects approach meeting a larger tolerance of ± 17%. These results showed improvement over uncalibrated models, which failed to meet tolerances as high as ± 30% for some species in a newly-fitted DBH growth model for Virginia, and as high as ± 170% for an existing model fitted to data from a much larger region of the Southeastern United States. Local calibration of regional DBH increment models provides an effective means of substantially reducing prediction errors when a relatively small set of observations are available from local sources such as permanent forest inventory plots, or the FIA database. / MS / The Forest Vegetation Simulator (FVS) is a growth and yield model widely-used for predicting stand dynamics, management and decision support in North American forests. Diameter increment is a major component in modeling tree growth. The system of integrated analytical tools in FVS is primarily based on the performance of the diameter increment model and the subsequent use of predicted in diameter at breast height (DBH) over time in forecasting tree attributes. To address the challenge of predicting growth in highly variable and geographically expansive forest systems, FVS was designed to include an internal calibration algorithm that makes use of growth observations, when available, from permanent inventory plots. The basic idea was that observed growth rates on a small set of remeasured trees are used to adjust or “calibrate” FVS growth predictions. The FVS internal calibration was the subject being investigated here. Five alternative methods were proposed attributed to a specific site or stand of interest and compared to two sets of results, which were based on median prediction errors, generated without calibration. Results illustrated that median-based methods or regression based methods performed better than the random-effects-based approach using independently observed growth data from Forest Service FIA re-measurements in Virginia. Local calibration of regional DBH increment models provides an effective means of substantially reducing prediction errors. The results of this study should also provide information to evaluate the efficiency of FVS calibration alternatives and a possible method for future implementation.

[ES] En los últimos años, las emisiones de hollín provenientes de los motores de combustión interna han recibido más atención debido al impacto negativo que éstas tienen no solo en el ambiente, sino también en la salud del ser humano. Como respuesta, leyes cada vez más estrictas han sido aplicadas impulsando así a la comunidad científica al desarrollo de motores más eficientes en el uso del combustible y por supuesto más limpios en términos de emisiones contaminantes. En este contexto, el modelado computacional ha sido la herramienta utilizada en numerosos esfuerzos que buscan contribuir a mejorar el entendimiento que se tiene sobre los altamente complejos fenómenos que componen el proceso de producción de hollín. El principal objetivo de esta tesis es simular la producción de hollín en chorros Diesel en condiciones de operación típicas de un motor de combustión interna utilizando CFD. La consecución del objetivo de la tesis comprende una evaluación preliminar de la configuración de los distintos modelos para el caso de chorros inertes. En segundo lugar, el estudio detallado de la hipótesis utilizada para caracterizar la estructura de la llama a nivel sub-grid (tomando como base los conceptos well-mixed o flamelet) y del enfoque para tener en cuenta la interacción entre turbulencia y química. Por último, se presentan resultados del modelado de la combustión y producción de hollín para diferentes condiciones de contorno de reactividad y mezcla del chorro utilizando un modelo de hollín de dos ecuaciones. En resumen, el lector encontrará a lo largo de este documento un estudio exhaustivo sobre la combustión y producción de hollín en chorros inyectados con toberas mono-orificio en ambientes quiescentes. De este tipo de chorros, el Spray A y Spray D de la Engine Combustion Network son utilizados como casos de referencia. / [CA] En els últims anys, les emissions de sutge provinents dels motors de combustió interna han rebut més atenció a causa de l'impacte negatiu que aquestes tenen no sols en l'ambient, sinó també en la salut de l'ésser humà. Com a resposta, lleis cada vegada més estrictes han sigut aplicades impulsant així a la comunitat científica al desenvolupament de motors més eficients en l'ús del combustible i per descomptat més nets en termes d'emissions contaminants. En aquest context, el modelatge computacional ha sigut l'eina utilitzada en nombrosos esforços que busquen contribuir a millorar l'enteniment que es té sobre els altament complexos fenòmens que componen el procés de producció de sutge. El principal objectiu d'aquesta tesi és simular la producció de sutge en rolls dièsel en condicions d'operació típiques d'un motor de combustió interna utilitzant CFD. La consecució de l'objectiu de la tesi comprèn una avaluació preliminar de la configuració dels diferents models per al cas de rolls inerts. En segon lloc, l'estudi detallat de la hipòtesi utilitzada per a caracteritzar l'estructura de la flama a nivell sub-grid (prenent com a base els conceptes well-mixed o flamelet) i de l'enfocament per a tindre en compte la interacció entre turbulència i química. Finalment, es presenten resultats del modelatge de la combustió i producció de sutge per a diferents condicions de contorn de reactivitat i mescla del doll utilitzant un model de sutge de dues equacions. En resum, el lector trobarà al llarg d'aquest document un estudi exhaustiu sobre la combustió i producció de sutge en dolls injectats amb toveres mono-orifici en ambients immòbils. D'aquesta mena de dolls, l'Spray A i Spray D de la Engine Combustion Network són utilitzats com a casos de referència. / [EN] Over the past few years, soot emissions from internal combustion engines have gained attention due to its impact on the environment and human health. In response, ever-stricter legislation has been enforced driving the research community toward more fuel-efficient and cleaner engines. Within this context, soot modeling has been the subject of many efforts seeking to contribute to the understanding of the highly complex phenomena that composes the soot production process. This thesis main objective aims at simulating soot production in Diesel sprays under engine-like conditions using computational fluid dynamics (CFD). The fulfillment of the thesis main objective entails a preliminary assessment of the inert spray computational setup for validation purposes. Then, a detailed study on the sub-grid flame structure and handling of turbulence-chemistry interaction is reported focusing on well-mixed and flamelet assumptions. Lastly, the study of reactivity and mixing boundary condition variations on combustion and soot production are assessed with a two-equation soot model. In summary, throughout this document the reader will find a comprehensive study of combustion and soot modeling in single-hole nozzle sprays in quiescent environments from which the Spray A and Spray D target conditions from the Engine Combustion Network are the main reference cases. / The respondent wishes to acknowledge the financial support received through Programa de Ayudas de Investigación y Desarrollo (PAID-01-16) and Ayudas para movilidad dentro del Programa para la Formación de Personal investigador 2017 of Universitat Politècnica de València and the Government of Spain through the CHEST Project (TRA2017-89139-C2-1-R). The respondent also wants to express his gratitude to Convergent Science for their kind support in the use of CONVERGE software for performing the CFD simulations. Parts of the work presented in this thesis have been supported in a collaborative framework with research partners at Argonne National Laboratory and their support is greatly acknowledged. / Pachano Prieto, LM. (2020). CFD modeling of combustion and soot production in Diesel sprays [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/142189

Yes / This paper presents a new method that provides the means to detect sunspots on full-disk solar images recorded by the Solar Diameter Imager and Surface Mapper (SODISM) on the PICARD satellite. The method is a totally automated detection process that achieves a sunspot recognition rate of 97.6%. The number of sunspots detected by this method strongly agrees with the NOAA catalogue. The sunspot areas calculated by this method have a 99% correlation with SOHO over the same period, and thus help to calculate the filling factor for wavelength (W.L.) 607nm.

Yes / The surface of the sun often shows visible sunspots which are located in magnetically active regions of the Sun, and whose number is an indicator of the Sun’s magnetic activity. The detection and classification of sunspots are useful techniques in the monitoring and prediction of solar activity. The automated detection of sunspots from digital images is complicated by their irregularities in shape and variable contrast and intensity compared with their surrounding area. The main aim of this paper is to detect sunspots using images from the Solar Diameter Imager and Surface Mapper (SODISM) on the PICARD satellite and calculate their filling factors. A comparison over time with sunspot numbers obtained using images from the SOHO satellite is also presented.

Roxtecs RM-moduler består av en kärna samt två profiler med ett bandpaket bestående av hoppressade blå och svarta band i vardera. I dagsläget kan kärnan till de mindre modulsorterna tillverkas först efter de övriga komponenterna provmonterats, då dess diameter behöver dimensioneras utifrån mätningar av de provmonterade bitarna för att få bra passform. Med målsättningen att eliminera de extra ställ- och väntetider som det här medför gjordes det här examensarbetet, i syftet att utreda ifall kärnorna till två av de här modulsorterna kan dimensioneras utifrån beräkningar baserade på uppmätta band- och profildimensioner. Arbetet inleddes med att generera mätdata för bandtjocklekarna och profilradierna, som sedan skulle användas för att beräkna tjockleken på bandpaketen och innerdiametern i modulerna. Det här genom att beräkna medelvärdet och spridningen för de här måtten, genom att bearbeta den generade mätdatan i Matlab med avseende på RSS-metoden. Beräkningssteget följdes av mätningar av innerdiametrar samt bandpaket, i syftet att verifiera resultaten som givits från beräkningarna. Resultatet från arbetet visade att beräkningarna för tjockleken på bandpaketen till de två modul A-batcherna, gav medelvärden som låg nära de tjocklekar som uppmättes för de pressade bandpaketen. Det visade även att de framräknade innerdiametervärdena var cirka en 1 procentenhet högre än de värden som uppmättes med måttpinnar, vilket innebar att kärnor med den framräknade diameter-värdena passade modulerna ganska bra. Däremot gav beräkningarna för modul B-batchen aningen lägre värden för bandpakets-tjockleken och betydligt högre värden för innerdiametrarna, än vad mätningarna för de här måtten gav, vilket kan bero på förekomst av felaktiga banddata. Å andra sidan avvek innerdiameterintervallet betydligt mer, vilket tyder på att den stora avvikelsen uppkom snarare vid beaktningen av profildatan. Därför är det lämpligt att testa arbetsmetoden för fler batcher för att kunna dra säkrare slutsatser gällande det här och metodens tillförlitlighet, samt för att enklare kunna identifiera eventuella förbättringsmöjligheter och mönster. Det här för att göra dimensioneringen av modulkärnorna mer tids- och kostnadseffektiv. / Roxtec’s RM modules consists of a core and two profiles, with a band package consisting of compressed blue and black band in each profile. In the present time, the cores to the small RM modules can be manufactured first after the other components have been test mounted, since the diameter must be dimensioned from measurements of the test mounted part to get a good fit. With the goal to eliminate the extra time for changeover and waiting that this entails, this bachelor thesis was done, with the purpose to investigate if the cores to two of these module sorts can be dimensioned from calculations based on measured band and profile dimensions. The work was started by generating data for the band thicknesses and the profile radiuses, which then were to use to calculate the thickness of the band packages and the inner diameter of the modules. This by calculating the average value and distribution of those things, by processing the data in Matlab considering the RSS method. The calculation step was followed by measurements of inner diameters and of band packages, in the purpose of verifying the results that had been from the calculations. The result from the bachelor thesis showed that the calculations for the thickness of the band packages for the two module A batches, gave average values close to measured value for the compressed band packages. It also showed that the calculated inner diameter values were approximately 1 percent unit higher than the values that was measured with cylindrical measuring pins, which meant that cores with the calculated diameter values fitted the modules quite good. On the contrary, the calculations for the module B batch gave slightly lower values for the band package thickness, and considerably higher values for the inner diameters, than the measurements of those things gave, which may be to occurrence of incorrect band data. On the other hand, the inner diameter interval deviated considerably more, which indicates that the great deviation occurs rather when the profile data is considered. Therefore, it is appropriate to test the work method for more batches to be able to make more accurate conclusions regarding that and the method’s reliability, and to make it easier to identify possible improvement opportunities and patterns. This to be make the dimensioning of the module cores more time and cost effective.

Στη διπλωματική εργασία προς παρουσίαση, πραγματευόμαστε ένα νέο είδος γραφημάτων, τα χρονικά γραφήματα, και διάφορες παραλλαγές τους. Ένα χρονικό γράφημα είναι μια διατεταγμενη τριάδα G={V,E,L}, όπου V ένα μη κενό πεπερασμένο σύνολο που καλείται σύνολο κορυφών, E ένα σύνολο m στοιχείων, καθένα από τα οποία είναι δισύνολο στοιχείων του V (καλείται σύνολο ακμών), και L= {L_e, για κάθε e στοιχείο του E} = {L_e_1, L_e_2, ..., L_e_m}, όπου L_e_i, i = 1,..., m, σύνολο θετικών ακεραίων τιμών που αντιστοιχίζονται στην ακμή e_i του συνόλου E (καλείται ανάθεση χρονικών ετικετών ή απλώς ανάθεση). Οι τιμές που αντιστοιχίζονται σε κάθε ακμή του γραφήματος καλούνται χρονικές ετικέτες της ακμής και δηλώνουν τις χρονικές στιγμές, κατά τις οποίες έχουμε τη δυνατότητα να τη διασχίσουμε (από το ένα της άκρο προς το άλλο). Για να αντιληφθεί κανείς το ενδιαφέρον των χρονικών γραφημάτων, μπορεί να σκεφτεί τη δυνατότητα εφαρμογής τους στην καθημερινότητα. Για παράδειγμα, οι χρονικές ετικέτες που ανατίθενται σε μία ακμή ενός κατευθυνόμενου χρονικού γραφήματος μπορούν να παραλληλιστούν με τις ώρες, στις οποίες γίνονται αναχωρήσεις αεροπλάνων από μία πόλη προς μια άλλη. Έτσι, η μελέτη των χρονικών γραφημάτων θα μπορούσε να συμβάλει στην οργάνωση των πτήσεων ενός αεροδρομίου. Ένα χρονικό μονοπάτι (ή «ταξίδι») σε ένα χρονικό γράφημα είναι ένα μονοπάτι, στις ακμές του οποίου μπορούμε να βρούμε αυστηρά αύξουσα σειρά χρονικών ετικετών. Στην εργασία, μεταξύ άλλων, γίνεται μελέτη της συνδετικότητας στα χρονικά γραφήματα, καθώς και κατασκευή και μελέτη αλγορίθμων εύρεσης χρονικών μονοπατιών («ταξιδίων») που φθάνουν το δυνατόν συντομότερα στον προορισμό τους (τελική κορυφή μονοπατιού). Επιπλέον, μελετώνται στατιστικά τα Χρονικά Γραφήματα, με επικέντρωση στο αναμενόμενο πλήθος χρονικών μονοπατιών σε ένα γράφημα, καθώς και στη Χρονική Διάμετρο ενός γραφήματος, όπως αυτή ορίζεται στην εργασία. / In the thesis, we are dealing with a new type of graphs,called Temporal Graphs, and several variants. A temporal graph is an ordered triplet G={V,E,L}, where V stands for a nonempty finite set (called set of vertices), E stands for a set of m elements, each of which are 2-element subsets of V (called set of edges), and L= {L_e, for all e in E} = {L_e_1, L_e_2, ..., L_e_m}, where L_e_i, i = 1, ..., m, is a set of positive integers mapped to edge e_i in E (called assignment of time labels or simply assignment). The values assigned to each edge of the graph are called time labels of the edge and indicate the times at which we can cross it (from one end to the other). In order to understand the interest of temporal graphs, one may think their applicability to everyday life. For example, the time labels assigned to an edge of a directed temporal graph can be paralleled to the flight departure times from one city to another. Therefore, the study of temporal graphs could contribute to the organization of flights at an airport. A temporal path (or «journey») in a temporal graph is a path, on the edges of which we can find strictly ascending time labels. In the thesis, among others, we study the connectivity of temporal graphs and we construct and study several algorithms that find temporal paths which arrive the soonest possible at their destination (final vertice of the path). Furthermore, we examine temporal graphs statistically, focusing on the expected number of temporal paths in a graph as well as in the Temporal Diameter of a graph, also defined in the thesis.