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This research explores the efficacy of word cards as a deliberate vocabulary learning technique and investigates the effects of testing on motivation for deliberate vocabulary study. While word cards are a widely supported method of deliberately studying target foreign language vocabulary, there is a surprising lack of research-based evidence supporting them, and very few researchers have asked students how they feel about word card learning. In addition, it is well known that testing can increase extrinsic motivation, but the motivational effects of regular vocabulary testing has so far been largely overlooked. The first two experiments in this study investigated the learning outcomes associated with making and studying from word cards. Experiment 1 is unique in that it is the first known study to isolate the learning outcomes of making word cards. The results indicated that the process of making word cards results in significant initial vocabulary learning, but a substantial amount of this new knowledge is lost in a relatively short period of time if no further study is carried out. The second experiment compared the use of self-made word cards with premade cards. The results indicated that although both methods are effective in the short and long-term, learners might be better studying from premade cards. However, the results of the third experiment led to the conclusion that premade cards are best suited to motivated learners. Qualitative data analysis revealed that learners generally have positive views of word card learning and understand the benefits it offers over other methods such as learning from lists or notebooks. The final experiment in this study examined the motivational effects of regular student-generated vocabulary testing and investigated whether learners can act as reliable raters of their peers’ vocabulary development. Results indicated that peer-to-peer vocabulary testing increases motivation for deliberate vocabulary learning even if test scores do not affect the students’ grades. Surprisingly, the student-generated and administered tests were more intrinsically motivating than extrinsically so. Taken together, the results of the various experiments offer support for the use of word cards for foreign language vocabulary learning and indicate that motivation for such types of learning can be increased by through peer testing. / Teaching & Learning

The nitrate radical (NO3·) was first identified as early as the 1881, but its role in atmospheric oxidation has only been identified within recent decades. Due to its high one-electron reduction potential and its reactivity toward a diverse set of substrates, it dominates nighttime atmospheric oxidation and has since been the subject of much work. Despite this, studies on NO3· hydrogen atom transfer reactions have been somewhat neglected in favor of its more reactive oxidative pathways. The first section of the dissertation will highlight the role of substrate structure, solvent effects, and the presence of a polar transition state on NO3· hydrogen abstractions from alcohols, alkanes, and ethers. In this work the acquisition of absolute rate constants from previously unexamined substrates was analyzed alongside a curated list of common organic pollutants degraded through hydrogen atom abstraction. It was found that NO3· reacts with low selectivity through an early polarized transition state with a modest degree of charge transfer. Compared to the gas-phase, condensed-phase reactions experience rate enhancement—consistent with Kirkwood theory—as a result of the polarized transition state. These insights are then applied to abstractions by NO3· from carboxylic acids in the next section. It was found that the rate constants for abstraction of α-carbons were diminished through induction by the adjacent carbonyl compared to the activation seen for the aforementioned substrates. The deactivation of abstraction by the carbonyl was found to be dramatically reduced as the substrate's alkyl chain was lengthened and/or branched. This apparent change in mechanism coincides with hydrogen abstraction of the alkyl chain for sufficiently large carboxylic acids and rules out the possibility of concerted bond breaking elsewhere in the molecule. Finally, the dissertation will cover some additional projects related to the overall nature of the work including examination of the kinetics of radical clock systems when complexed with metal ions and the examination of a highly oxidative biosourced monomer. / Doctor of Philosophy / The nitrate radical (NO3·) was first identified as early as the 1881, but its role in the breakdown of atmospheric pollutants has only been identified within recent decades. Operating primarily at night, NO3· serves as a major atmospheric oxidant—it breaks down pollutants by reactions that involve the removal of electrons from those substrates. This chemistry is particularly important in understanding the consequences of an increasingly industrialized world and the subsequent short-term health and environmental implications. Geographically, these reactions will occur in large concentrations near locations that contribute greatly to atmospheric pollution, such as above coal-powered plants, heavily industrialized areas, above the canopy of large forests, and immediately behind the engines of airplanes as they move through the sky. The proximity of these locations to large population centers has caused the pollutants to greatly impact human health. These contaminants have been linked to several of the leading global causes of death, such as ischemic heart disease, stroke, and respiratory illnesses. The first section of the dissertation will focus on the role of pollutant structure, the medium in which the reaction occurs, and the development of a charged complex when NO3· reacts with alcohols, alkanes, and ethers. These substrates are often found as the result of incomplete combustion when burning fuel or as products of even more sustainable biodiesels. In this work the exact rate constants were found for substrates that were previously unexamined and compared with similar known reaction rates. It was found that NO3· has a low preference for what it reacts with and passes through a modestly charged complex early in the reaction. Compared to gaseous reactions, reactions in a liquid environment proceed faster due to the formation of a charged complex. This was then applied to reactions with carboxylic acids in the next section. Carboxylic acids are often found in large concentrations above the canopy of large forests resulting from the oxidation of isoprenes that are naturally released from broad-leaf trees. It was found that these reactions were slower than reactions with alkanes as the development of the charged complex was inhibited due to the presence of an adjacent dipole. When the carboxylic acid was longer and/or more branched, the formation of the charged complex was no longer inhibited as the reaction site moved further from the dipole. A change in reaction pathway was observed when the acids were sufficiently large. This ruled out the possibility of the reaction occurring simultaneously with a fracturing and rearrangement elsewhere. Finally, the dissertation will cover some additional projects that share some overlap with the work already described including the study of the rates of radical clock systems in the presence of metal ions and the study of naturally sourced monomers that are prone to losing electrons.

Due to the rapid proliferation of the World Wide Web (WWW) in recent years, many educators are now seeking to improve the effectiveness of their instruction by providing interactive, web-based course material to their students. The purpose of this thesis is to document a set of eight online learning modules created to improve the effectiveness of learning the fundamentals of Computer Science. The modules are as follows: • <A HREF="http://courses.cs.vt.edu/csonline/Algorithms/Lessons/index.html">Algorithms</A> - Definition and specification of algorithms, with a comparison and analysis of several sorting algorithms as examples. • <A HREF="http://courses.cs.vt.edu/csonline/AI/Lessons/index.html">Artificial Intelligence</A> - Overview of current applications in this discipline. • <A HREF="http://courses.cs.vt.edu/csonline/DataStructures/Lessons/index.html">Data Structures</A> - Explanation of basic data structures, including an introduction to computer memory and pointers, and a comparison of logical and physical representations of commonly used data structures. • <A HREF="http://courses.cs.vt.edu/csonline/MachineArchitecture/Lessons/index.html">Machine Architecture</A> - Explanation of data storage, gates and circuits, and the central processing unit. • <A HREF="http://courses.cs.vt.edu/csonline/NumberSystems/Lessons/index.html">Number Systems</A> - Discussion of number representation and arithmetic in number systems other than the decimal number system, with a focus on binary numbers and binary arithmetic. • <A HREF="http://courses.cs.vt.edu/csonline/OS/Lessons/index.html">Operating Systems</A> - Explanation of the purpose of operating systems and the major components that make up an operating system. • <A HREF="http://courses.cs.vt.edu/csonline/ProgrammingLanguages/Lessons/index.html">Programming Languages</A> - Explanation of the fundamental concepts in procedural programming languages. • <A HREF="http://courses.cs.vt.edu/csonline/SE/Lessons/index.html">Software Engineering</A> - Introduction to software life cycle models and an overview of the procedural and object-oriented paradigms. Each module consists of a set of lessons and review questions written in HyperText Markup Language (HTML). Embedded in these pages are various interactive components implemented as Flash animations or Java applets. The modules currently reside on the Computer Science courseware server of Virginia Polytechnic Institute and State University (Virginia Tech) and can be viewed at the following WWW site: <A HREF="http://courses.cs.vt.edu/csonline/index.html">http://courses.cs.vt.edu/csonline/</A> / Master of Science

[ES] La inyección de combustible es, entre los temas de investigación de motores, una de las piezas críticas para obtener un motor eficiente. El papel es aún más significativo cuando se persigue una estrategia de inyección directa. La geometría interna y el movimiento de la aguja determinan el comportamiento del flujo del inyector, que se sabe que afecta enormemente al desarrollo externo del spray y, en última instancia, al rendimiento de la combustión dentro de la cámara. La conciencia sobre el cambio climático y los contaminantes ha ido creciendo, impulsando el esfuerzo en motores más limpios. En este sentido, los motores de gasolina tienen un margen más amplio para mejo- rar que los motores diesel. La evolución de los antiguos PFI a las modernas estrategias de inyección directa, que se utilizan en los motores de nueva generación, demuestra esta tendencia. Los sistemas GDI tienen el potencial de cumplir con las estrictas emisiones y aumentar el ahorro de combustible, sin embargo, todavía se enfrenta a muchos desafíos. Este trabajo implica el uso de dos inyectores, uno es una moderna tobera de GDI de investigación designada por el Engine Combustion Network (ECN), y el otro es una unidad de inyección de producción (PIU) con la misma tecnología y una geometría ligeramente diferente. Ambos equipos se someten a una completa caracterización (flujo interno y externo) que abarca las técnicas más avanzadas en diversas instalaciones experimentales. Además, se diseña y construye una nueva instalación para realizar experimentos en condiciones de evaporación instantánea (cuando la presión de vapor del combustible inyectado es superior a la presión del volumen de descarga). La instalación construida está diseñada para simular un ambiente de descarga en ciertas condiciones del motor en las que podrían producirse fenómenos de flash boiling. Así, debido a las propiedades típicas del combustible de gasolina, era un requisito operar con presiones de cámara de 0,2 a 15 bares. Además, la temperatura ambiente se controlaba mediante la implementación de una resistencia que puede calentar el gas ambiente. La instalación funciona en un bucle abierto, pudiendo renovar el volumen de gas entre las inyecciones. Por último, se construyeron tres amplios accesos ópticos para acomodar muchas técnicas de diagnóstico óptico como DBI, MIE, shadowgraphy o PDA, entre otros. Para la evaluación del flujo interno se determinó la geometría de las toberas y la orientación de los agujeros, el movimiento de la aguja y, por último, la caracterización del ratio de inyección (ROM) y el momento de inyección (ROI) de ambas toberas. La geometría de las toberas y la elevación de la aguja se midieron mediante técnicas avanzadas de rayos X en el Laboratorio Nacional de Argonne (ANL). Las mediciones de ROI y ROM se realizaron utilizando las instalaciones de CMT-Motores Térmicos siguiendo los conocimientos técnicos aplicados en los inyectores de gasóleo y adaptándolos a las toberas de GDI. El ROI nos permitió comparar las boquillas, cuyo número de orificios y geometría eran diferentes, aunque entregan aproximadamente la misma cantidad de combustible. Se ensayó la respuesta a condiciones típicas de motor como variaciones en la presión del rail, la presión de descarga, la temperatura del combustible, etc. Para el inyector de investigación "Spray G", se desarrolló un modelo 0-D de la velocidad de inyección que permite obtener la señal para diferentes condiciones y duración de la inyección, lo cual es útil para la calibración del motor y la validación del CFD. Además, para la caracterización de la ROM, se desarrolló la metodología de la técnica de deformación plástica para obtener la orientación del cono del spray y orientar adecuadamente los chorros de combustible para la medición de ROM. En el análisis hidráulico se combinaron los datos para estudiar los bajos valores del coeficiente de descarga y / [CA] La injecció de combustible és, entre els temes d'investigació de motors, una de les peces crítiques per a obtindre un motor eficient. El paper és encara més significatiu quan es persegueix una estratègia d'injecció directa. La geometria interna i el moviment de l'agulla determinen el comportament del flux de l'injector, que se sap que afecta enormement el desenvolupament extern de l'esprai i, en última instància, al rendiment de la combustió dins de la cambra. La consciència sobre el canvi climàtic i els contaminants ha anat creixent, impulsant l'esforç en motors més nets. En aquest sentit, els motors de gasolina tenen un marge més ampli per a millorar que els motors dièsel. L'evolució dels antics PFI a les modernes estratègies d'injecció directa, que s'utilitzen en els motors de nova generació, demostra aquesta tendència. Els sistemes GDI tenen el potencial de complir amb les estrictes emissions i aug- mentar l'estalvi de combustible, no obstant això, encara s'enfronta a molts desafiaments. Aquest treball implica l'ús de dos injectors, un és una moderna tovera de GDI d'investigació designada pel Engine Combustion Network (ECN), i l'altre és una unitat d'injecció de producció (PIU) amb la mateixa tecnologia i una geometria lleugerament diferent. Tots dos equips se sotmeten a una completa caracterització (flux intern i extern) que abasta les tècniques més avançades en diverses instal·lacions experimentals. A més, es dissenya i construeix una nova instal·lació per a realitzar experiments en condicions d'evaporació instantània (quan la pressió de vapor del combustible injectat és superior a la pressió del volum de descàrrega). La instal·lació construïda està dissenyada per a simular un ambient de descàrrega en certes condicions del motor en les quals podrien produir-se fenòmens de flash boiling. Així, a causa de les propietats típiques del combustible de gasolina, era un requisit operar amb pressions de cambra de 0,2 a 15 bars. A més, la temperatura ambient es controlava mitjançant la implementació d'una resistència que pot calfar el gas ambiente. La instal·lació funciona en un bucle obert, podent renovar el volum de gas entre les injeccions. Finalment, es van construir tres amplis accessos òptics per a acomodar moltes tècniques de diagnòstic òptic com DBI, MIE, shadowgraphy o PDA, entre altres. Per a l'avaluació del flux intern es va determinar la geometria de les toveres i l'orientació dels forats, el moviment de l'agulla i, finalment, la caracterització del ràtio d'injecció (ROM) i el moment d'injecció (ROI) de totes dues toveres. La geometria de les toveres i l'elevació de l'agulla es van mesurar mitjançant tècniques avançades de raigs X en el Laboratori Nacional de Argonne (ANL). Els mesuraments de ROI i ROM es van realitzar utilitzant les instal·lacions de CMT-Motores Térmicos seguint els coneixements tècnics aplicats en els injectors de gasoil i adaptant-los a les toveres de GDI. El ROI ens va permetre comparar els filtres, el nombre d'orificis dels quals i geometria eren diferents, encara que entreguen aproximadament la mateixa quantitat de combustible. Es va assajar la resposta a condicions típiques de motor com a variacions en la pressió del rail, la pressió de descàrrega, la temperatura del combustible, etc. Per a l'injector d'investigació "Esprai G", es va desenvolupar un model 0-D de la velocitat d'injecció que permet obtindre el senyal per a diferents condicions i duració de la injecció, la qual cosa és útil per al calibratge del motor i la validació del CFD. A més, per a la caracterització de la ROM, es va desenvolupar la metodologia de la tècnica de deformació plàstica per a obtindre l'orientació del con de l'esprai i orientar adequadament els dolls de combustible per al mesurament de ROM. En l'anàlisi hidràulica es van combinar les dades per a estudiar els baixos valors del coeficient de descàrrega i del coeficient d'àr / [EN] Fuel injection is among the engine research topics one of the critical pieces to obtain an efficient engine. The role is even more significant when a direct injection strategy is pursued. The internal geometry and pintle movement determine the injector flow behavior, which is known to hugely affect the external spray development and, ultimately, the combustion performance inside the chamber. Climate change and pollutants awareness has been growing, pushing forward the effort on cleaner engines. In this regard, gasoline en- gines have a wider margin to improve than diesel engines. The evolution from old Port Fuel Injectors to modern direct injection strategies, which are used in new generation engines, demonstrates this trend. GDI systems have the potential to comply with stringent emissions and increase fuel economy, however, it still faces many challenges. This work involves the use of two injectors, one is a modern research GDI nozzle appointed by the Engine Combustion Network (ECN), and the other is a production injector unit (PIU) with the same technology and slightly different geometry. Both hardware's undergo a complete characterization (internal and external flow) covering the state- of-the-art techniques in various experimental facilities. Furthermore, a new facility is designed and built to perform experiments under flash boiling conditions (when the fuel injected's vapor pressure is higher than the pressure in the discharge volume). The developed facility is designed to simulate a discharge ambient at certain engine conditions in which flash boiling phenomena could occur. Thus, due to typical gasoline fuel properties, it was a requirement to operate from chamber pressures from 0.2 bar to 15 bar. Also, the ambient temperature was controlled by implementing a resistor that can heat the ambient gas. The facility operates in an open loop, being able to renovate the gas volume between injections. Finally, three wide optical accesses were built to accommodate many optical diagnostic techniques such as DBI, MIE, shadowgraphy, or PDA, among others. For the internal flow description, it was determined the nozzles geometry and holes orientation, the pintle movement, and finally, the characterization of the rate of momentum (ROM) and rate of injection (ROI) of both nozzles. The nozzles geometry and needle lift were measured using advanced optical x-ray techniques at Argonne National Laboratory (ANL). The ROI and ROM measurements were performed using CMT-Motores Térmicos facilities follow- ing the know-how applied in diesel injectors and adapting it to GDI nozzles. The ROI allowed us to compare the nozzles, whose orifices number and geometry were different, although they deliver approximately the same amount of fuel. It was tested their response to typical boundary conditions such as rail pressure, discharge pressure, fuel temperature, etc. For the research nozzle "Spray G", it was developed a 0-D model of the rate of injection allowing to obtain the signal for different injection duration and conditions, which is useful in engine calibration and CFD validation. Furthermore, for the ROM characterization, the plastic deformation technique methodology was developed to obtain spray cone orientation and adequately guide the fuel jets for measuring ROM. The hydraulic analysis combined the data to study the low discharge coefficient and area coefficient values, which could result from low needle lift combined with novel hole designs in both nozzles that promote cavitation and air interaction from inside the orifice. In the external flow characterization, it was used the new developed vessel to study the external spray covering flash boiling conditions. It was employed four surrogate fuels to simulate different volatility properties of gasoline com- pounds and ultimately reproduce more extreme flashing conditions. It was used lateral visualization using DBI and Schlieren in addition to frontal MIE visualization. Some of t / Bautista Rodríguez, A. (2021). Study of the Gasoline Direct Injection Process under Novel Operating Conditions [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/167809

[EN] Bile acids are a family of amphiphilic steroids that play a pivotal role in physiological functions such as elimination of cholesterol or solubilization of lipids. Chemically, they share a steroidal skeleton with an unusual cis fusion between rings A and B, a short lateral chain ending in a carboxylic acid moiety and different number of hydroxyl groups on the alpha-face. Hence, bile acids offer a versatile architecture that can be used to investigate photophysical processes of interest such as hydrogen atom transfer, through-bond energy trasfer, through-bond exciplex formation and DNA photodamage-related reactions. First, unmodified bile acids have been used to evaluate hydrogen atom trasfer to benzophenone-like triplet carbonyls. Dehydrogenation of bile acids at positions C-3 and/or C-7 by a radical-mediated mechanism from the excited state of benzophenone has been demonstrated. Moreover, synthesized lithocholic acid derivatives including benzophenone or carbazole as donors and a naphthalene, biphenyl or thymine as acceptors have been employed to investigate through-bond energy transfer and exciplex formation processes. Thus, energy transfer from benzophenone to naphthalene or biphenyl and extended through-bond exciplex formation in benzophenone/naphthalene and benzophenone/biphenyl linked systems has been demostrated by laser flash photolysis. Finally, bile acid derivatives incorporating one benzophenone and two thymine units with different degrees of freedom have been prepared to investigate the photochemical formation of oxetanes or thymine dimers. Photosensitized formation of cyclobutane pyrimidine dimers through the generation of a delocalized triplet excited state has been demonstrated in intermolecular systems, while oxetane formation is observed when the degrees of freedom are reduced. / [ES] Los ácidos biliares son una familia de esteroides anfifílicos que juegan un papel clave en diferentes funciones fisiológicas tales como la eliminación del colesterol o la solubilización de lípidos. Su estructura química está constituida por un esqueleto esteroideo con una fusión cis poco común entre los anillos A y B, una cadena lateral corta que termina con una función ácida y un número variable de grupos hidroxilo en la cara alfa. Por tanto, los ácidos biliares ofrecen una estructura versátil que puede ser utilizada para investigar procesos fotofísicos de interés como abstracción de hidrógeno, transferencia de energía y formación de exciplejos a larga distancia o reacciones relacionadas con el daño fotoinducido al ADN. En esta Tesis, en primer lugar, los ácidos biliares naturales se han utilizado para evaluar la abstracción de hidrógeno a carbonilos triplete en compuestos derivados de la benzofenona, demostrándose la deshidrogenación de los ácidos biliares en las posiciones C-3 y/o C-7 por un mecanismo radicalario desde el mencionado triplete de la benzofenona. En segundo lugar, se han preparado derivados de ácido litocólico que incluyen los dadores benzofenona o carbazol y los aceptores naftaleno, bifenilo o timina, que a continuación se han utilizado para investigar los procesos de transferencia de energía y formación de exciplejo intramolecular a larga distancia. De hecho, en los sistemas benzofenona/naftaleno y benzofenona/bifenilo, se demostró por fotólisis de destello láser la transferencia de energía desde benzofenona a naftaleno o bifenilo y la formación de exciplejo a larga distancia. Por último, se han preparado derivados de ácidos bliares que incorporan una unidad de benzofenona y dos de timina en diferentes posiciones del esqueleto para investigar la influencia de los diferentes grados de libertad en la formación fotosensibilizada de oxetanos o dímeros de timina. Gracias a ellos, se ha demostrado la formación fotosensibilizada de dímeros ciclobutánicos pirimidínicos a través de la generación de estados excitados triplete deslocalizados en sistemas en los que la benzofenona es intermolecular, mientras que se observa formación de oxetanos cuando los grados de libertad se ven reducidos. / [CA] Els àcids biliars són una família d'esteroides anfifílics que juguen un paper clau en funcions fisiològiques com l'eliminació del colesterol o la solubilització de lípids. La seua estructura química està constituïda per un esquelet esteroïdal amb una fusió cis entre els anells A i B poc comuna, una cadena lateral curta que acaba amb una funció àcida i un nombre diferent de grups hidroxil en la cara alfa. D'aquesta manera, els àcids biliars ofereixen una estructura versàtil que pot ser utilitzada per investigar processos fotofísics d'interès com abstracció d'hidrogen, transferència d'energia i formació de exciplexes a llarga distància o reaccions relacionades amb el dany a l'ADN induït per llum. En primer lloc, els àcids biliars naturals s'han utilitzat per avaluar la abstracció d'hidrogen a carbonils triplets derivats de la benzofenona, demostrant-se la deshidrogenació dels àcids biliars en les posicions C-3 i/o C-7 per un mecanisme radicalari des de l'estat excitat de la benzofenona. A més, derivats d'àcid litocòlic que inclouen els donadors benzofenona o carbazol i els acceptors naftalé, bifenil o timina s'han utilitzat per investigar els processos de transferència d'energia i formació de exciplexe a llarga distància. En els sistemes benzofenona /naftalé i benzofenona/bifenil la fotòlisis làser va demostrar la transferència d'energia des de benzofenona a naftalé o bifenil i la formació d'exciplexe a llarga distància. Finalment, per tal d'investigar la formació fotosensibilitzada d'oxetans o dímers de timina, s'han preparat derivats d'àcids bliars que incorporen una unitat de benzofenona i dues de timina amb diferents graus de llibertat. La formació fotosensibilitzada de dímers ciclobutànics pirimidínics mitjançant la generació d'estats excitats triplet deslocalitzats ha estat demostrada en sistemes intermoleculars, mentre que la formació d'oxetans s'observa quan els graus de llibertat es veuen reduïts. / Miró Richart, P. (2016). Hydrogen-Abstraction, Energy Transfer and Exciplex Formation in Photoactive Systems Based on Bile Acids [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/64084