Given the increasing consciousness toward the environmental footprint of mobility, accommodating environmental objectives in existing transport planning strategies is imperative for research and practice. In this paper, we use the link macroscopic fundamental diagram (MFD) model to develop optimal routing strategies that minimize total system emissions (TSE) in multiple origin-destination (OD) networks. Piecewise linear (PWL) functions are used to approximate MFD for individual links, and to define link-level emissions. Dynamic network constraints, non-vehicle holding constraints, and convex formulations of the PWL functions are considered. Thus, the system-optimum dynamic traffic assignment (SO-DTA) problem with environmental objectives is formulated as a mixed integer linear program (MILP). Finally, on a synthetic network, numerical examples demonstrate the performance of the proposed framework.

Spin-vortices in vertically spaced pairs of thin elliptical Permalloy nanoparticles are investigated. The two vortex cores with parallel out-of-plane magnetization exhibit a strong monopole-like attraction through the spacer much thinner than the core length, thus forming a bound core-core pair. The material of the spacer is designed to suppress both direct and indirect exchange interactions, so the remaining inter-vortex coupling is purely dipolar. In the investigated vortex pairs, the in-plane magnetization in the vortex periphery, outside the vortex cores, curl in opposite directions (have opposite chirality). As a result, the two cores move in opposite directions in response to an in-plane magnetic field, the Zeeman effect of which acts to decouple the core-core pair. This leads to unique dynamics of the spin-vortex parallel-core/antiparallel-chirality pair, which strongly depend on whether the pair is coupled or decoupled. In the coupled state, the cores are held close together by the core-core attraction, which results in short-radius oscillations and a resonance frequency of about 2 GHz for the main rotational eigen-mode. In the decoupled state, the cores are separated by a distance much greater than the core length and gyrate independently with a resonance frequency of the order of 100 MHz. The dynamics of the vortex pair are investigated at 77 K, where there is a bistability between the coupled and decoupled core states. Resonant excitations are used to decouple the cores with pulses of ∼10 Oe in amplitude and ∼100 ps in duration. The ability to decouple a vortex pair using such fast low-power pulses can be useful for multifrequency oscillators and vortex based memory. A search for quantum effects is undertaken at sub-Kelvin temperatures using a dilution refrigerator. Square pulses of 100 ns duration and amplitudes of the order of 1 Oe are applied in-plane to bring the system closer to decoupling, giving the cores a chance to tunnel through the barrier between the coupled and decoupled states. The amplitude required for decoupling is measured as a function of temperature and a leveling off in the decoupling probability is seen below 400 mK, giving some indication of core tunneling. Macroscopic quantum tunneling of magnetization is interesting from the fundamental physics point of view, e.g., as a model system for studying the measurement paradox in quantum mechanics, as well as for current and future computer technology in terms of understanding the ultimate limitations of miniaturizing magnetic memory elements. / I detta arbete studeras spinnvirvlar i elliptiska skivor av Permalloy ordnade i vertikala par. Kärnor av parallell vertikal magnetisering attraherar varandra likt monopoler genom en film mycket tunnare än kärnorna och bildar därmed ett sammankopplat par. Materialet i filmen mellan virvlarna är designat för att förhindra både direkt och indirekt utbytesväxelverkan och lämnar endast kärnornas dipolväxelverkan. I de virvelpar som studeras går den plana magnetiseringen i virvlarnas periferi runt kärnorna åt olika håll (de har motsatt kiralitet). På grund av detta rör sig kärnorna åt olika håll vid applikation av magnetfält i planet (Zeeman effekten) vilket kan leda till att de kopplas isär. Detta ger virvelpar med parallella kärnor och antiparallell kiralitet unika dynamiska egenskaper som ändras med deras tillstånd, sammankopplade eller isärkopplade. I det sammankopplade tillståndet hålls kärnorna ihop av monopolattraktionen vilket gör att de bara kan röra sig i små banor kring sitt magnetiska masscentrum, med en resonansfrekvens på circa 2 GHz. I det isärkopplade tillståndet är kärnorna separerade med ett avstånd som är mycket större än kärnornas diameter, och de rör sig oberoende av varandra med en resonansfrekvens i storleksordningen 100 MHz. Virvelparets dynamik undersöks vid 77 K, där det finns en bistabilitet mellan det sammankopplade och det isärkopplade tillståndet. Pulser med längd ∼100 ps och styrka ∼10 Oe i resonans med det sammankopplade tillståndet används för att koppla isär kärnorna. Att kunna koppla isär dem med så korta lågeffektspulser kan vara användbart för virvelbaserade minnen och multifrekvensoscillatorer. Ett sökande efter kvanteffekter påbörjas vid temperaturer under 1 K med hjälp av en utspädningskyl. Fyrkantsvågor med en längd på 100 ns och en styrka i storleksordningen 1 Oe, orienterade i planet, används för att ge kärnorna en chans att tunnla genom barriären mellan det sammankopplade och det isärkopplade tillståndet. Den vågamplitud som krävs för att koppla isär kärnorna plottas mot temperaturen och kan ses plana ut under 400 mK, vilket ger viss indikation av tunnling. Dessa undersökningar av makroskopisk kvanttunnling av magnetisering kan vara användbar i grundforskning för att studera mätparadoxen i kvantmekanik, men också i modern datorteknologi för att förstå de absoluta begränsningarna i hur små magnetiska minneselement kan göras.

Due to the escalating demand for traffic information and management, the significance of traffic state estimation, which involves the assessment of traffic conditions on road segments with limited measurement data, is increasing. Two primary estimation methods are model-driven and data-driven. The former uses traffic flow models, while the latter relies on extensive historical data to explore relationships between traffic states. Due to the uninterrupted nature of highway traffic flow, conventional model-driven approach is adopted in the study to estimate traffic information from sensing data. Data-driven approach is applied to enhance the estimation results. The project mainly focuses on comparing the estimation performance between the Particle Filter and the commonly used Extended Kalman Filter. These two methods are implemented in combination with two typical traffic flow models: Cell Transmission Model and METANET. Moreover, the project investigates the potential of using vehicle-to-everything (V2X) data in traffic state estimation, either alone or combined with traditional inductive loop detector (ILD) data. Being an emerging traffic data source, V2X communication has been recently installed and tested on the motorways near Stockholm. This study provides essential insights into how V2X data can benefit existing traffic information estimation and its performance. To evaluate the models mentioned above, the estimation algorithms and traffic flow models are implemented in a self-developed platform, which may be useful for further work. Results from simulation experiments show that Particle Filter can carry out traffic state estimation with comparable accuracy to Extended Kalman Filter. While standalone V2X speed data falls short, effective fusion methods are implemented to combine both data types, ultimately achieving the desired accuracy. These fusion methods encompass direct filtering, weighted averaging, and linear regression. Future investigations could broaden their scope to include new data sources, such as unmanned aerial vehicles (UAVs), and delve into advanced data fusion techniques, such as deep learning. / På grund av den ökande efterfrågan på trafikinformation och trafikhantering ökar betydelsen av trafiklägesuppskattning, vilket innebär bedömning av trafikförhållandena på vägsegment med begränsade mätningsdata. Två primära uppskattningsmetoder är modellbaserade och datadrivna metoder. Den förra använder trafikflödesmodeller, medan den senare förlitar sig på omfattande historiska data för att utforska samband mellan trafiklägen. På grund av det oavbrutna vägtrafikflödet antas en konventionell modellbaserad metod i studien för att uppskatta trafikinformation från sensordata. Den datadrivna metoden används för att förbättra estimatresultaten. Projektet fokuserar främst på att jämföra prestandan i uppskattningen mellan Partikelfiltret och den vanligtvis använda Extended Kalman Filter. Dessa två metoder implementeras i kombination med två typiska trafikflödesmodeller: Cell Transmission Model och METANET. Dessutom undersöker projektet möjligheterna att använda fordons-till-allt (V2X) data i trafiklägesuppskattning, antingen ensamt eller i kombination med data från traditionella induktiva slingdetektorer (ILD). Som en framväxande källa till trafikdata har V2X-kommunikation nyligen installerats och testats på motorvägarna nära Stockholm. Denna studie ger väsentlig inblick i hur V2X-data kan gynna befintlig uppskattning av trafikinformation och dess prestanda. För att utvärdera ovan nämnda modeller implementeras uppskattningsalgoritmerna och trafikflödesmodellerna i en självutvecklad plattform, vilket kan vara användbart för framtida arbete. Resultaten från simuleringsexperiment visar att Partikelfiltret kan utföra trafiklägesuppskattning med jämförbar noggrannhet jämfört med Extended Kalman Filter. Medan fristående V2X-hastighetsdata inte når hela vägen fram implementeras effektiva sammanslagningsmetoder för att kombinera båda datatyperna och slutligen uppnå önskad noggrannhet. Dessa sammanslagningsmetoder omfattar direkt filtrering, viktad medelvärdesbildning och linjär regression. Framtida undersökningar kan utvidga deras omfattning för att inkludera nya datakällor, såsom obemannade flygfordon (UAV:er), och utforska avancerade tekniker för datafusion, såsom djupinlärning.

The Aw-Rascle-Zhang (ARZ) model has become a favorable ``second order" macroscopic traffic model, which corrects several shortcomings of the Payne-Whitham (PW) model. The ARZ model possesses a family of flow rate versus density (FD) curves, rather than a single one as in the ``first order" Lighthill-Whitham-Richards (LWR) model. This is more realistic especially during congested traffic state, where the historic fundamental diagram data points are observed to be set-valued. However, the ARZ model also possesses some obvious shortcomings, e.g., it assumes multiple maximum traffic densities which should be a ``property" of road. Instead, we propose a Generalized ARZ (GARZ) model under the generic framework of ``second order" macroscopic models to overcome the drawbacks of the ARZ model. A systematic approach is presented to design generic ``second order" models from historic data, e.g., we construct a family of flow rate curves by fitting with data. Based on the GARZ model, we then propose a phase-transition-like model that allows the flow rate curves to coincide in the free flow regime. The resulting model is called Collapsed GARZ (CGARZ) model. The CGARZ model keeps the flavor of phase transition models in the sense that it assume a single FD function in the free-flow phase. However, one should note that there is no real phase transition in the CGARZ model. To investigate to which extent the new generic ``second order" models (GARZ, CGARZ) improve the prediction accuracy of macroscopic models, we perform a comparison of the proposed models with two types of LWR models and their ``second order" generalizations, given by the ARZ model, via a three-detector problem test. In this test framework, the initial and boundary conditions are derived from real traffic data. In terms of using historic traffic data, a statistical technique, the so-called kernel density estimation, is applied to obtain density and velocity distributions from trajectory data, and a cubic interpolation is employed to formulate boundary condition from single-loop sensor data. Moreover, a relaxation term is added to the momentum equation of selected ``second order" models to address further unrealistic aspects of homogeneous models. Using these inhomogeneous ``second order" models, we study which choices of the relaxation term &tau are realistic. / Mathematics

Travel-time information is essential in Advanced Traveler Information Systems (ATISs) and Advanced Traffic Management Systems (ATMSs). A key component of these systems is the prediction of the spatiotemporal evolution of roadway traffic state and travel time. From the perspective of travelers, such information can result in better traveler route choice and departure time decisions. From the transportation agency perspective, such data provide enhanced information with which to better manage and control the transportation system to reduce congestion, enhance safety, and reduce the carbon footprint of the transportation system. The objective of the research presented in this dissertation is to develop a framework that includes three major categories of methodologies to predict the spatiotemporal evolution of the traffic state. The proposed methodologies include macroscopic traffic modeling, computer vision and recursive probabilistic algorithms. Each developed method attempts to predict traffic state, including roadway travel times, for different prediction horizons. In total, the developed multi-tool framework produces traffic state prediction algorithms ranging from short – (0~5 minutes) to medium-term (1~4 hours) considering departure times up to an hour into the future. The dissertation first develops a particle filter approach for use in short-term traffic state prediction. The flow continuity equation is combined with the Van Aerde fundamental diagram to derive a time series model that can accurately describe the spatiotemporal evolution of traffic state. The developed model is applied within a particle filter approach to provide multi-step traffic state prediction. The testing of the algorithm on a simulated section of I-66 demonstrates that the proposed algorithm can accurately predict the propagation of shockwaves up to five minutes into the future. The developed algorithm is further improved by incorporating on- and off-ramp effects and more realistic boundary conditions. Furthermore, the case study demonstrates that the improved algorithm produces a 50 percent reduction in the prediction error compared to the classic LWR density formulation. Considering the fact that the prediction accuracy deteriorates significantly for longer prediction horizons, historical data are integrated and considered in the measurement update in the developed particle filter approach to extend the prediction horizon up to half an hour into the future. The dissertation then develops a travel time prediction framework using pattern recognition techniques to match historical data with real-time traffic conditions. The Euclidean distance is initially used as the measure of similarity between current and historical traffic patterns. This method is further improved using a dynamic template matching technique developed as part of this research effort. Unlike previous approaches, which use fixed template sizes, the proposed method uses a dynamic template size that is updated each time interval based on the spatiotemporal shape of the congestion upstream of a bottleneck. In addition, the computational cost is reduced using a Fast Fourier Transform instead of a Euclidean distance measure. Subsequently, the historical candidates that are similar to the current conditions are used to predict the experienced travel times. Test results demonstrate that the proposed dynamic template matching method produces significantly better and more stable prediction results for prediction horizons up to 30 minutes into the future for a two hour trip (prediction horizon of two and a half hours) compared to other state-of-the-practice and state-of-the-art methods. Finally, the dissertation develops recursive probabilistic approaches including particle filtering and agent-based modeling methods to predict travel times further into the future. Given the challenges in defining the particle filter time update process, the proposed particle filtering algorithm selects particles from a historical dataset and propagates particles using data trends of past experiences as opposed to using a state-transition model. A partial resampling strategy is then developed to address the degeneracy problem in the particle filtering process. INRIX probe data along I-64 and I-264 from Richmond to Virginia Beach are used to test the proposed algorithm. The results demonstrate that the particle filtering approach produces less than a 10 percent prediction error for trip departures up to one hour into the future for a two hour trip. Furthermore, the dissertation develops an agent-based modeling approach to predict travel times using real-time and historical spatiotemporal traffic data. At the microscopic level, each agent represents an expert in the decision making system, which predicts the travel time for each time interval according to past experiences from a historical dataset. A set of agent interactions are developed to preserve agents that correspond to traffic patterns similar to the real-time measurements and replace invalid agents or agents with negligible weights with new agents. Consequently, the aggregation of each agent's recommendation (predicted travel time with associated weight) provides a macroscopic level of output – predicted travel time distribution. The case study demonstrated that the agent-based model produces less than a 9 percent prediction error for prediction horizons up to one hour into the future. / Ph. D.

This thesis studies the influence of internal nozzle flow characteristics over a large spectrum of experimental conditions and diagnostics. Experiments were carried out for two nozzle geometries---cylindrical and conical single hole nozzles---and three different fuels. Two of the fuels are pure components---n-heptane and n-dodecane---while the third fuel consists of a three-component surrogate to better represent the physical and chemical properties of diesel fuel. Measurements include a complete hydraulic characterization consisting of instantaneous injection rate and spray momentum flux measurements; a high-speed visualization of isothermal liquid spray; a high-speed visualization of the evaporative inert spray, imaging liquid and vapor phases simultaneously and finally, a high-speed visualization of the high temperature reactive spray, imaging vapor phase and OH* chemiluminescence for each injection event. All high-temperature diagnostics were performed in a continuous flow test chamber that allows an accurate control on a wide range of thermodynamic conditions (up to 1000 K and 15 MPa). The experimental findings from this work, and the large database obtained (available for download at: http://www.cmt.upv.es/DD01.aspx), could be used to validate CFD models that could help the community understand the fundamental driving mechanisms behind these observations. / En esta tesis se estudia la influencia del flujo interno sobre un amplio espectro de condiciones y diagnósticos experimentales. Se realizaron experimentos para dos geometrías de tobera---toberas cilíndrica y cónica de un único orificio---y tres combustibles. Dos de los combustibles son puros---n-heptano y n-dodecano--- mientras el tercero es un combustible sustituto que consiste en una mezcla de tres componentes que busca representar mejor las propiedades físicas y químicas del diesel. Las medidas incluyen una caracterización hidráulica completa, compuesta por tasa de inyección y cantidad de movimiento instantáneas; una visualización de alta velocidad del chorro líquido isotermo; una visualización de alta velocidad del chorro inerte evaporativo, con captura simultánea de las fases líquida y vapor y, finalmente, una visualización del chorro reactivo a alta temperatura, con captura de la fase vapor y la quimioluminiscencia del radical OH* para cada evento de inyección. Todos los diagnósticos en condiciones de alta temperatura fueron realizados en una maqueta de alta presión y temperatura de flujo constante que permite controlar con precisión un rango amplio de condiciones termodinámicas (hasta 1000 K y 15 MPa). Los resultados experimentales y la gran base de datos obtenida en este trabajo (disponible en: http://www.cmt.upv.es/DD01.aspx), podrían ser utilizados para validar modelos CFD detallados que podrían ayudar a la comunidad científica a entender mejor los mecanismos fundamentales que producen los resultados observados. / Aquesta tesi estudia la influència del flux intern sobre un gran espectre de condicions i diagnòstics experimentals. Es van realitzar experiments per a dos geometries de tovera---toveres ci¿líndrica i cónica amb un únic orifici---i tres combustibles. Dos dels combustibles són purs---n-heptà i n-dodecà--- mentre el tercer combustible consisteix en una mescla de tres components que formen un combustible substitut que busca representar millor les propietats físiques i químiques del dièsel. Les mesures inclouen una caracterització hidràulica completa, composta per taxa d'injecció i quantitat de moviment instantanis; visualització d'alta velocitat del doll líquid isoterme; visualització d'alta velocitat del doll inert evaporatiu, capturant simultàniament les fases líquid i vapor i, finalment, una visualització del doll reactiu a alta temperatura, capturant la fase vapor i la quimioluminiscència del radical OH per a cada esdeveniment d'injecció. Tots els diagnòstics en condicions d'alta temperatura van ser realitzats en una insta¿lació d'alta pressió i temperatura amb flux constant que permet controlar amb precisió un ampli rang de condicions termodinàmiques (fins a 1000 K i 15 MPa). Els resultats experimentals i la gran base de dades obtinguda en aquest treball (disponible a la web en: http://www.cmt.upv.es/dd01.aspx), podrien ser utilitzats per tal de validar models CFD detallats que podrien ajudar a la comunitat científica a entendre millor els mecanismes fonamentals que produeixen aquestes observacions. / Viera Sotillo, JP. (2017). Experimental study of the effect of nozzle geometry on the performance of direct-injection diesel sprays for three different fuels [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/81857

En la exploración de nuevos métodos para el mejoramiento de la eficiencia y rendimiento del motor diésel, es claro que un gran esfuerzo debe estar enfocado en el proceso de inyección de combustible. La eficiencia de la combustión y las emisiones, se ven muy afectadas por el proceso de atomización, y se ha demostrado que incrementos en presiones de inyección conllevan un gran potencial para mejorar el ahorro de combustible, producir mejores mezclas de aire y combustible, y por tanto menor generación de emisiones contaminantes. Últimamente, las presiones de inyección han aumentado de alrededor de 50 MPa en los años 70 hasta 250 MPa en los días actuales. Presiones de inyección muy altas (250-300 MPa) o incluso ultra altas (> 300 MPa) vienen siendo materia de investigación con el fin de ser implementadas de manera comercial en un futuro próximo. La estructura y desarrollo del spray diésel pueden ser caracterizados desde un punto de vista microscópico por medio de la medición del tamaño de gotas del spray y sus velocidades. En condiciones no-evaporativas, técnicas como el PDPA (Phase Doppler Particle Analyzer) vienen siendo utilizadas para la obtención de perfiles de diámetros y velocidades de gota con una alta resolución temporal. Desde el punto de vista macroscópico, existen parámetros específicos que permiten caracterizar a un chorro diésel, estos son: la penetración de vapor y líquida junto con el ángulo de apertura del chorro. La penetración líquida es un indicador claro de la capacidad de evaporación del combustible utilizado, mientras que la penetración de vapor, por su parte, es indicativo del proceso de mezcla y la probabilidad de colisión con las paredes de la cámara de combustión; factores claves a la hora de la generación de emisiones contaminantes. En esta tesis se estudia la influencia de presiones bajas, medias y muy altas presiones inyección, sobre un amplio espectro de condiciones y diagnósticos experimentales, y desde el punto de vista macroscópico y microscópico. Se realizaron experimentos para tres diferentes inyectores, 2 solenoides y un piezo eléctrico, este último con la capacidad de alcanzar presiones de inyección cercanas a 270 MPa. Las medidas incluyen una caracterización hidráulica, compuesta por tasa de inyección; una visualización de alta velocidad del chorro líquido isotermo; una visualización de alta velocidad del chorro inerte evaporativo, con captura simultánea de las fases líquida y vapor; y finalmente, una caracterización microscópica por medio de la obtención de distribución de tamaño de gotas y sus velocidades. Con respecto a los ensayos microscópicos, se desarrolló una metodología para el aislamiento y alineación de sprays con un error de medición muy bajo de 0,22°. Se llevaron a cabo mediciones de velocidad de gotas, cuyos resultados mostraron buen ajuste con perfiles teóricos de velocidad. De igual manera, una correlación para el tamaño de gota SMD se obtuvo mostrando un alto nivel de ajuste y siendo representativa para todo el rango de presiones de inyección estudiados. En el caso de la caracterización macroscópica del chorro isotermo, se han detectado variaciones macroscópicas en el desarrollo del chorro con propiedades de gas, inclusive en condiciones de motor comunes. Para estimar estos efectos y otros que las presiones de inyección muy altas tendrían sobre la estructura del chorro, se incentivó la aparición de ondas de choque controlando la velocidad del sonido del ambiente. Se usaron tres gases ambientales (SF6 N2 y CO2) con diferentes velocidades de sonido, promoviendo de esta manera chorros supersónicos en determinados casos. Al comparar ensayos con mismas densidades y diferentes gases ambientales, se encontró que todas las tendencias cercanas al estado transónico (0.8 <M <1.2) tenían una mayor penetración y menor ángulo de chorro. / En l'exploració de nous mètodes per al millorament de l'eficiència i rendiment del motor dièsel, és clar que un gran esforç s'ha enfocar en el procés d'injecció de combustible. L'eficiència de la combustió i les emissions, es veuen molt afectades pel procés d'atomització, i s'ha demostrat que increments en pressions d'injecció comporten un gran potencial per a millorar l'estalvi de combustible, produir millors mescles d'aire i combustible, i per tant menor generació d'emissions contaminants. Últimament, les pressions d'injecció han augmentat d'al voltant de 50 MPa en els anys 70 fins a 250 MPa en els dies actuals. Pressions d'injecció molt altes (250-300 MPa) o inclús ultra altes (> 300 MPa) vénen sent matèria d'investigació a fi de ser implementades de manera comercial en un futur pròxim. L'estructura i desenrotllament de l'esprai dièsel poden ser caracteritzats des d'un punt de vista microscòpic per mitjà del mesurament de la grandària de gotes de l'esprai i les seues velocitats. En condicions no-evaporatives, tècniques com el PDPA (Phase doppler particle analyzer) vénen sent utilitzades per a l'obtenció de perfils de diàmetres i velocitats de gota amb una alta resolució temporal. Des del punt de vista macroscòpic, hi ha paràmetres específics que permeten caracteritzar a un doll dièsel, estos són: la penetració de vapor i la penetració líquida junt amb l'angle d'obertura del doll. La penetració líquida és un indicador clar de la capacitat d'evaporació del combustible utilitzat, mentres que la penetració de vapor, per la seua banda, és indicatiu del procés de mescla i la probabilitat de col·lisió amb les parets de la cambra de combustió; factors claus a l'hora de la generació d'emissions contaminants. En esta tesi s'estudia la influència de pressions d' injecció baixes, mitges i molt altes, sobre un ampli espectre de condicions i diagnòstics experimentals, i des del punt de vista macroscòpic i microscòpic. Es van realitzar experiments per a tres injectors diferents, 2 solenoides i un piezo elèctric, este últim amb la capacitat d'aconseguir pressions d'injecció pròximes a 270 MPa. Les medides inclouen una caracterització hidràulica, composta per taxa d'injecció; una visualització d'alta velocitat del doll líquid isoterm; una visualització d'alta velocitat del doll inert evaporativo, amb captura simultània de les fases líquida i vapor; i finalment, una caracterització microscòpica per mitjà de l'obtenció de distribució de grandària de gotes i les seues velocitats. Respecte als assajos microscòpics, es va desenrotllar una metodologia per a l'aïllament i alineació d'esprais amb un error de mesurament molt davall de 0,22°. Es van dur a terme mesuraments de velocitat de gotes, els resultats van mostrar bon ajust amb perfils teòrics de velocitat. De la mateixa manera, una correlació per a la grandària de gota SMD es va obtindre mostrant un alt nivell d'ajust i sent representativa per a tot el rang de pressions d'injecció estudiats. En el cas de la caracterització macroscòpica del doll isoterm, s'han detectat variacions macroscòpiques en el desenrotllament del doll amb propietats de gas, inclusivament en condicions de motor comú. Per a estimar estos efectes i altres que altes pressions d'injecció tindrien sobre l'estructura del doll, es va incentivar l'aparició d'ones de xoc controlant la velocitat del so de l'ambient. Es van usar tres gasos ambientals (SF6, N2 i CO2) amb diferents velocitats de so, promovent d'esta manera dolls supersònics en determinats casos. Al comparar assajos amb mateixes densitats i diferents gasos ambientals, es va trobar que totes les tendències pròximes a l'estat transónic (0.8 < M < 1.2) tenien una major penetració i menor angle de doll. Respecte al doll evaporatiu, per a pressions d'injecció molt altes com 270MPa, els efectes dels paràmetres ambientals i d'injecció van romandre iguals respecte a totes les carac / In the exploration of new methods for improving the efficiency and performance of the diesel engine, it is clear that a great effort should be focused on the fuel injection process. The efficiency of combustion and emissions are greatly affected by the atomization process, and it is considered that injection pressures increments have a great potential to improve fuel economy, produce better air and fuel mixtures, and thus low generation of polluting emissions. Lately, injection pressures have increased from around 50 MPa in the 70's to 250 MPa in the current days, even very high injection pressures (250-300 MPa) or ultra high pressures (> 300 MPa) have been the subject of the scientific community in order to be implemented in future injection systems. The structure and development of the diesel spray can be characterized from a microscopic point of view by means of estimation of droplets size and velocities. At non-evaporative conditions, techniques such as PDPA (Phase Doppler Particle Analyzer) are being used to obtain diameters and velocity profiles a with high temporal resolution. From the macroscopic point of view, there are specific parameters that allow characterizing the diesel spray, these are: the liquid and vapor penetration along with the spray angle. The liquid penetration is a clear indicator of the evaporation capacity of the fuel used, whilst the vapor penetration, on the other hand, is an indicative of the mixing process and the probability of collision with the combustion chamber walls; key factors when generating polluting emissions. In this thesis the influence of low and very high injections pressures over the macro and micro characteristics of the diesel spray is studied, over a wide spectrum of conditions and experimental diagnoses. Experiments were carried out for three different injectors, two solenoids and one piezoelectric, the latter with the capacity to reach injection pressures close to 270MPa. The measurements include a hydraulic characterization; a high speed visualization of the liquid spray at isothermal conditions; a high-speed visualization of the evaporative spray, with simultaneous capture of the liquid and vapor phases; and finally, a microscopic characterization. Regarding the microscopic tests, a methodology was developed for the spray isolation and alignment with a very low measurement error of 0.22° Droplets velocity measurements were carried out, the results showed good adjustment with theoretical velocity profiles. Similarly, a correlation for SMD droplet size was obtained showing a high level of adjustment and being representative for the entire range of injection pressures studied. In the case of the macroscopic characterization of the isothermal spray, variations have been detected in the development of the jet with gas properties, even at common engine injection conditions. To estimate these effects and others that very high injection pressures would have on the spray structure, the apparition of shock waves was enhanced by controlling the speed of sound of the environment using three ambient gases with different speed of sound (SF6, N2 and CO2). When comparing tests with same densities and different ambient gases, it was found that all the tendencies near the transonic state (0.8 <M <1.2) had a higher penetration and lower spray angle. With respect to the evaporative jet, for very high injection pressures like 270MPa, the effects of the environmental and injection parameters remained the same with respect to all the macroscopic characteristics. / Giraldo Valderrama, JS. (2018). Macroscopic and microscopic characterization of non-reacting diesel sprays at low and very high injection pressures [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/113643

[pt] A Mecânica Quântica é uma das teorias mais bem sucedidas de todos os tempos. Não apenas tem um grande poder preditivo, como também mudou completamente a maneira como entendemos a física. No entanto, a Mecânica Quântica não prevê o próprio alcance, e, em princípio, a descrição probabilística deveria ser válida em nosso mundo macroscópico. Mas isso não acontece. Um ponto central do porquê a descrição quântica é substituída pela Mecânica Clássica, é a descoerência. A interação dos muitos graus de liberdade de um ambiente macroscópico faz com que seja extremamente difícil medirmos as propriadades quânticas de um sistema. Nesse contexto, exploramos como ainda podemos detectar efeitos não-clássicos de osciladores harmônicos em um regime intermediário, através da optomecânica. Neste trabalho apresentamos fundamentos do formalismo da optomecânica, tanto a dinâmica unitária, quanto para sistemas quânticos abertos. Depois, discutimos dois sistemas optomecânicos distintos, ressaltando como podemos investigar a presença de características quânticas. Além disso, discutiremos outras abordagens para identifcar características quânticas de osciladores harmônicos em situações cada vez mais próximas ao regime macroscópico. / [en] Quantum Mechanics is one of the most successful theories of all time. It not only has a great predictive power, but also has completely changed the way physics is understood. However, Quantum Mechanics does not predict its own range of validity, and, in principle, the probabilistic description should be valid in our macroscopic world. But it does not happen. In the core of the explanation of why the description from Quantum Mechanics is substituted by Classical Mechanics lies decoherence. The interaction of the many unseen degrees of freedom from a macroscopic environment with a quantum system makes it extremely hard to measure its quantum properties. In this context, we explore how one can still detect non-classicality of oscillators in a intermediate regime, whether in a mesoscopic scale or a oscillator with a macroscopic number of excitations, via an optomechanical description. In this work, we present the basics of the formalism of optomechanics, both in the unitary dynamics and in an open quantum system approach. We then discuss two different optomechanical systems, highlighting how we can perceive its quantum features. At last, we discuss other possible schemes to identify the quantum nature of harmonic oscillators in situations of increasing macroscopic nature.

In der Humanmedizin wird zur Beurteilung der Magenschleimhautproben das aktualisierte Sydney-System nach STOLTE (1997) angewendet. Das Ziel war es herauszufinden, ob das histologische Grading System auch in der Veterinärmedizin, für die Beurteilung von Pferdemagenschleimhautpräparaten, genutzt werden kann und ob daraus neue Erkenntnisse erwachsen. Von 60 Pferden wurden direkt post mortem Schleimhautproben aus der Pars glandularis (Drüsenschleimhaut), im Bereich der großen Kurvatur und dem Pylorus, entnommen. Die Patienten wurden in 4 Gruppen, 10 operierte (Kolik)pferde, 36 Pferde mit Kolik und infauster Prognose, 6 Pferde mit hochgradigen Magenulzera und 8 Pferde, die nicht auf Grund einer Kolik euthanasiert wurden, eingeteilt. Die makroskopische Beurteilung der 60 Pferdemägen erfolgte nach MURRAY et al. (1989) und MACALLISTER et al. (1995). Die histopathologische Beurteilung erfolgt in der Humanmedizin anhand der Helicobacter-like-Organismen Dichte, dem Grad der chronischen Entzündung, der Aktivität der Gastritis, der Atrophie und der intestinalen Metaplasie. Nach diesen Beurteilungsvariablen wurden die 120 Proben aus den 60 Pferdemägen beurteilt. Die ätiologischen Diagnosen sind in der Humanmedizin das Ergebnis jahrzehntelanger Forschung. Beim Pferd liegen dagegen zur Ätiologie der Gastritis noch keine gesicherten Erkenntnisse vor. Beim Pferd gibt es bestimmte Gastritisformen, die denen des Menschen ähnlich sind. Doch können die morphologischen Befunde in der Veterinärmedizin, nach den jetzigen Erkenntnissen, keinen Ätiologien zugeordnet werden. Die ätiologischen Diagnosen in dieser veterinärmedizinischen Studie beruhen auf der Diagnostik am Menschen und wurden noch nicht auf ihre Richtigkeit beim Pferd überprüft. Von den 60 untersuchten Pferdemägen wiesen 31 makroskopisch Läsionen in der Magenschleimhaut auf. 20 Pferde mit Veränderungen hatten diese in der Pars glandularis. Bei 44 der Pferde bestätigt der histologische Befund, nach dem aktualisierten Sydney- System, das makroskopische Grading. 13 der Pferde hatten nach dem aktualisierten Sydney-System histologisch einen pathologischen Befund, obwohl makroskopisch die Schleimhaut keine Auffälligkeiten aufwies. Bei nur 3 von den 60 Pferden konnte der histologische den makroskopischen Befund nicht bestätigen. Ätiologisch wurde, nach humanmedizinischen Beurteilungskriterien, bei 18 Pferden im Bereich der großen Kurvatur der Pars glandularis und, oder im Bereich des Pylorus eine C-Gastritis (chemische Gastritis), bei 11 Pferden eine like B-Gastritis (bakterielle Gastritis ohne den Nachweis von Helicobacter-like-Organismen), 3 Pferden eine B-Gastritis (bakterielle Gastritis mit dem Nachweis von Helicobacter-like-Organismen) und bei 9 Pferden eine Sonderform der Gastritis diagnostiziert. 6 Pferde bekamen die Diagnose: zur Zeit nicht klassifizierbar und 7 Pferde die deskriptive Diagnose erosive oder ulzerative Gastritis gestellt. 24 Pferde hatten keinen pathologischen Befund in einem der oben genannten Bereiche der Schleimhaut. Die histopathologischen Befunde der Pferde mit einer like-B-Gastritis oder einer B-Gastritis entsprachen nach humanmedizinischen Gesichtspunkten dem Bild einer Helicobacter-pylori-Gastritis beim Menschen. Bandartige Anordnung der Lymphozyten in der Lamina propria mucosae und neutrophile Granulozyten in Verbindung mit einer Atrophie des Drüsenkörpers, intestinaler Metaplasie und Erosionen. Bei drei Pferden konnte in der Warthin–Starry-Färbung und in der IHC-Reaktion Helicobacter-like-Organismen nachgewiesen werden. Die Pylorusschleimhaut war doppelt so häufig, im Vergleich zur Drüsenschleimhaut der großen Kurvatur, von einer like-B-Gastritis oder B-Gastritis betroffen. Die histologische Auswertung von Magenschleimhautbioptaten, in dieser Studie nach dem aktualisierten Sydney-System aus der Humanmedizin, komplettiert die makroskopische (endoskopische) Diagnostik. Nach den Ergebnissen der vorliegenden Studie gehört in der Pferdemedizin zu jeder Gastroskopie die Bioptatentnahme. Das aktualisierte Sydney-System kann in Zukunft in der Veterinärmedizin als Arbeitsgrundlage für die weitere wissenschaftliche Forschung genutzt werden. / Stolte’s updated Sydney system is used in the field of human medicine for grading the gastric mucosa (STOLTE 1997). The goal of this study was to determine whether this system could also be applied for histological parameter grading in veterinary medicine, in order to gain new insights into medications for treating equine gastric mucosa. Post mortem biopsies of mucosa were taken from 60 equines along the greater curve and pylorus of the pars glandularis. The test animals were divided into four groups: 10 post-colic surgery equines, 36 with colic and an infaust prognosis, six with chronic EGUS (equine gastric ulcer syndrome), and eight equines not euthanized for reasons other than colic. Macroscopic grading of the 60 equine stomachs was performed in accordance with MURRAY et al. (1989) and MACALLISTER et al. (1995). In human medicine, histological scoring is based on the following five parameters: density of Helicobacter-like organisms, grade of the chronic inflammation, level of gastric activity, atrophy, and intestinal metaplasia. A total of 120 biopsies taken from the 60 equines were graded according to these parameters. Etiologic diagnoses for humans are the outcome of decades of research, but the etiology of equine gastritis lacks an equivalent foundation. Equines exhibit forms of gastritis similar to those in humans, but their morphology cannot be classified into any specific etiology. In this study, the etiological diagnoses were based on human diagnostics, but their validity for equines has yet to be substantiated. Of the 60 equine stomachs examined, 31 showed lesions in the gastric mucosa, while 20 of those with changes had lesions in the pars glandularis. Histological findings of 44 equines confirmed the macroscopic grading according to the updated Sydney system. Thirteen equines exhibited pathological findings based on the updated Sydney system histology, although no abnormalities were discovered in the macroscopic examination. The histological diagnosis did not confirm the macroscopic grading for only three of the 60 subjects. The following etiological findings were reached in terms of human medicine: 18 equines with type C gastritis (chemical gastritis) along the greater curve of the pars glandularis and/or pylorus, 11 equines with type B-like gastritis (bacterial gastritis without evidence of H-like organisms), three equines with type B gastritis (bacterial gastritis with evidence of H-like organisms), and nine with a special form of gastritis. Six of the equines could not be classified, while seven showed erosive gastritis or ulceration. A total of 24 equines exhibited no pathological findings along any of the above-mentioned mucosae. The histopathological findings of the equines with either type B-like gastritis or type B gastritis corresponded with H pylori gastritis seen in humans, as ligamental lymphocytes in the lamina propria mucosae and neutrophilic granulocytes associated with atrophy of the glandular corpus, intestinal metaplasia, and erosion. Warthin-Starry staining and the IHC reaction confirmed H-like organisms in three of the equines. The frequency of type B-like gastritis or type B gastritis was observed to be twice as high in the pylorus mucosa as along the glandular mucosa of the greater curve. This study has demonstrated that histological analysis of gastric mucosa biopsies graded according to the updated Sydney system for human medicine significantly complements veterinary gastroscopy, which should therefore always include a biopsy. The updated Sydney system can thus serve as a platform for future scientific research in the field of veterinary medicine.

The study investigated South African Grade 10 Physical science learners’ reasoning about basic chemical phenomena at sub-microscopic level. The study adopted a non-experimental, exploratory and descriptive method and was principally guided by the ex-post facto research design using a concurrent embedded strategy of mixed qualitative and qualitative approach. A total of 280 grade 10 physical science learners in their intact classes and six of their teachers participated in the study. The 280 physical science learners comprised of 100 students from two top performing schools, 100 learners from two middle performing schools and the last 80 learners were drawn from two poor performing schools in Gauteng Department of Education’s Tshwane North District. A two-tier multiple-choice paper and pencil Test of Basic Chemistry Knowledge (TBCK) based on the three levels of chemical representation of matter was administered to the 280 physical science learners in their Grade 11 first term to collect both quantitative and qualitative data. In addition to the TBCK, focus group discussions (FGDs) with learners, teacher interviews and document analysis were used to triangulate data. The results revealed that most Grade 10 learners find it easy to identify pure elements and the solid state but find it difficult to negotiate between the three levels (macroscopic, sub-microscopic and symbolic) of chemical representation of matter. It became clear that learners experienced more difficulties in the concepts of basic solutions, acidic solutions, concentration and ionic compounds in solution. It also became apparent that some learners could not tell differences between a diatomic element and a compound indicating conceptual problems when they reason at particle level, and as a result they could not identify a mixture of elements. The results also indicated that the concepts of pure compounds and mixtures of compounds were not easy to comprehend as most learners took a pure compound for a mixture of atoms and a mixture of compounds for a mixture of elements. It is therefore concluded that learners find it difficult negotiating the three levels of chemical representation of matter. However, it is not clear whether the misconceptions the learners showed could be completely attributable to the concepts involved or the nature of the sub-microscopic models that were used in the test as it was also revealed that most teachers were not using sub-microscopic representations during instruction to enable learners to think at particle level. Furthermore, justifications to the multiple-choice tasks revealed lack of understanding of basic chemical concepts as well as language problems amongst learners as they could not clearly express their reasoning. Based on the results, some recommendations to educators, chemistry curriculum planners, teacher education and the chemistry education research field are suggested. / Science and Technology Education / D. Phil. ((Philosophy in Mathematics, Science and Technology Education)