Group (pooled) testing, i.e., testing multiple subjects simultaneously with a single test, is essential for classifying a large population of subjects as positive or negative for a binary characteristic (e.g., presence of a disease, genetic disorder, or a product defect). While group testing is used in various contexts (e.g., screening donated blood or for sexually transmitted diseases), a lack of understanding of how an optimal grouping scheme should be designed to maximize classification accuracy under a budget constraint hampers screening efforts. We study Dorfman and Array group testing designs under subject-specific risk characteristics, operational constraints, and imperfect tests, considering classification accuracy-, efficiency-, robustness-, and equity-based objectives, and characterize important structural properties of optimal testing designs. These properties provide us with key insights and allow us to model the testing design problems as network flow problems, develop efficient algorithms, and derive insights on equity and robustness versus accuracy trade-off. One of our models reduces to a constrained shortest path problem, for a special case of which we develop a polynomial-time algorithm. We also show that determining an optimal risk-based Dorfman testing scheme that minimizes the expected number of tests is tractable, resolving an open conjecture. Our case studies, on chlamydia screening and screening of donated blood, demonstrate the value of optimal risk-based testing designs, which are shown to be less expensive, more accurate, more equitable, and more robust than current screening practices. / PHD / Group (pooled) testing, i.e., testing multiple subjects simultaneously with a single test, is essential for classifying a large population of subjects as positive or negative for a binary characteristic (e.g., presence of a disease, genetic disorder, or a product defect). While group testing is used in various contexts (e.g., screening donated blood or for sexually transmitted diseases), a lack of understanding of how an optimal grouping scheme should be designed to maximize classification accuracy under a budget constraint hampers screening efforts. We study Dorfman and Array group testing designs under subject-specific risk characteristics, operational constraints, and imperfect tests, considering classification accuracy-, efficiency-, robustness-, and equity-based objectives, and characterize important structural properties of optimal testing designs. These properties provide us with key insights and allow us to model the testing design problems as network flow problems, develop efficient algorithms, and derive insights on equity and robustness versus accuracy trade-off. We also show that determining an optimal risk-based Dorfman testing scheme that minimizes the expected number of tests is tractable, resolving an open conjecture. Our case studies, on chlamydia screening and screening of donated blood, demonstrate the value of optimal risk-based testing designs, which are shown to be less expensive, more accurate, more equitable, and more robust than current screening practices.

The thesis investigates the concept of trademark dilution under international and regional trademark law, and under the laws of selected jurisdictions; namely, the United States of America, Germany, the United Kingdom and the Republic of South Africa. The investigation includes measures undertaken to prohibit the internet-based dilution of famous marks through the registration of confusingly similar domain names. It is noted that dilution is imprecisely formulated under international trademark treaty law. In fact, the term "dilution" does not appear in international trademark treaties. To fill the gap of international trademark treaties, various policy initiatives, or `soft law' have been developed, which to some extent clarify both the concept of dilution, the type of mark protected from dilution, and the scope of such protection. The problem is that the policy initiatives are non-binding on States, so that different States have adopted different common law and statutory approaches to the protection of marks against dilution. This is demonstrated, for example, by the fact that the European Union and its Member States provide protection from dilution to "marks with a reputation", while the United States of America provides such protection only to "famous" marks, and the Republic of South Africa protects "marks which are well-known in the Republic" from dilution. The thesis analyses the protection granted in these jurisdictions, to determine the similarities and differences of approach, and to make appropriate law reform proposals to achieve uniformity of protection. In the final analysis, it is concluded that the burden of enforcing dilution provisions rest on the judiciary. This being so, the judiciary is urged to engage in a balancing exercise in deciding dilution cases. The courts should recognize that dilution provisions are powerful tools at the disposal of owners of trademarks with advertising value. At the same time, the courts should be steadfast in ensuring that protection from dilution does not stultify freedom of trade, or create absolute monopolies or a form of copyright in a trademark. / Jurisprudence / LL.D.

The thesis investigates the concept of trademark dilution under international and regional trademark law, and under the laws of selected jurisdictions; namely, the United States of America, Germany, the United Kingdom and the Republic of South Africa. The investigation includes measures undertaken to prohibit the internet-based dilution of famous marks through the registration of confusingly similar domain names. It is noted that dilution is imprecisely formulated under international trademark treaty law. In fact, the term "dilution" does not appear in international trademark treaties. To fill the gap of international trademark treaties, various policy initiatives, or `soft law' have been developed, which to some extent clarify both the concept of dilution, the type of mark protected from dilution, and the scope of such protection. The problem is that the policy initiatives are non-binding on States, so that different States have adopted different common law and statutory approaches to the protection of marks against dilution. This is demonstrated, for example, by the fact that the European Union and its Member States provide protection from dilution to "marks with a reputation", while the United States of America provides such protection only to "famous" marks, and the Republic of South Africa protects "marks which are well-known in the Republic" from dilution. The thesis analyses the protection granted in these jurisdictions, to determine the similarities and differences of approach, and to make appropriate law reform proposals to achieve uniformity of protection. In the final analysis, it is concluded that the burden of enforcing dilution provisions rest on the judiciary. This being so, the judiciary is urged to engage in a balancing exercise in deciding dilution cases. The courts should recognize that dilution provisions are powerful tools at the disposal of owners of trademarks with advertising value. At the same time, the courts should be steadfast in ensuring that protection from dilution does not stultify freedom of trade, or create absolute monopolies or a form of copyright in a trademark. / Jurisprudence / LL.D.

Ces travaux de thèse portent sur la physico-chimie de l'interface fibre/matrice appliquée aux composites Carbone/Carbone. La surface des fibres de carbone est modifiée par divers traitements de surface (voie gazeuse et voie humide). L'impact de ces différents procédés sur l'état de surface des fibres a été évalué par chromatographie gazeuse en phase inverse à dilution infinie, MEB, AFM, MET, RAMAN… Suite à ces caractérisations, des traitements de surface ont été retenus pour la réalisation de composite C/C. Les propriétés notamment mécaniques des matériaux composites à interfaces modulées (force de la liaison fibre/matrice) ont pu être évaluées. Finalement, il a pu être établi une relation entre modifications de surface des fibres de carbone et comportement macroscopique des composites C/C. / This work focuses on the physical chemistry of the fiber/matrix interface applied to composites carbon/carbon. The surface of carbon fibers was modified by various surface treatments. The carbon fibers surface variation was evaluated by inverse gas chromatography at infinite dilution, SEM, AFM, TEM, Raman... After these characterizations, surface treatments were selected for the realization of C/C composites. The mechanical properties of composites at modulated interfaces (fibers/matrix bonding) were evaluated. Finally, a correlation between surface modification of carbon fibers and macroscopic behavior of composite C/C was established.

Ce travail s'intéresse à la compréhension du comportement des flammes non-prémélangées issues d'un jet de méthane assisté par un coflow d'air dilué avec du CO2, ou d'autres gaz chimiquement inertes pour discriminer les différents phénomènes impliqués dans la dilution. Les phénomènes transitionnels, décrochage et extinction, quantifiés par des limites de stabilité, sont analysés à l'aide de grandeurs physiques représentatives. Le domaine de stabilité de flamme est limité par des surfaces 3D dans le domaine physique ( Qdiluant/Qair (taux de dilution), Uair (vitesse d'air), UCH4 (vitesse de méthane)), révélant un effet compétitif entre l'aérodynamique et la dilution. Des cartographies génériques de décrochage et d'extinction communes à tous ces diluants sont proposées. Des grandeurs liées à la stabilisation sont toutes soumises à des lois d'évolution auto-simlilaires. Il en ressort que la vitesse de propagation de flamme est l'élément clé du mécanisme de stabilisation lors de la dilution. / This work focuses on the understanding of the behaviours of non-premixed methane flame inside an air coflow diluted by carbon dyoxide (CO2) or by other chemically inert diluents in order to discriminate different phenomena involved in dilution. Transitional phenomena (liftoff and extinction) quantified trough the stability limits, are analyzed trough representative physical quantities. The flame stability domain is limited by 3D-surfaces (liftoff and extinction) in the physical domain (Qdiluant/Qair (dilution level), Uair (air velocity), UCH4 (methane velocity)) revealing a competitive effect between aerodynamics and dilution. Generic diagrams of flame liftoff and extinction are proposed for all the diluents. Physical quantities related to flame stabilization process are all submitted to, regardless of diluent, self-similar laws. This is explained by flame burning velocity which is considered as the key element in the flame stabilization mechanism with air-side dilution.

Ce travail de thèse porte sur l’analyse des effets de la recirculation des gaz de combustion, via l’étude de la dilution par le dioxyde de carbone et plus particulièrement de la vapeur d’eau sur des flammes méthane/air enrichi en dioxygène, dans le cas d’une combustion prémélangée pressurisée rencontrée dans les turbines à gaz. Des mesures de vitesses de flammes CH4/O2/H2O/N2 laminaires pressurisées ont été obtenues à l’aide d’une flamme sphérique se propageant librement dans une enceinte close. L’analyse des résultats expérimentaux a permis de vérifier la validité du schéma cinétique GRIMech ?3.0 au travers des calculs numériques de flammes libres monodimensionnelles. Des calculs complémentaires ont permis l’établissement d’une base de données (vitesse de flamme laminaire, longueur de Markstein et nombre de Lewis, température adiabatique de combustion et épaisseur de flamme) en fonction des paramètres d’entrées de la combustion (température, pression, X(H2O), richesse et enrichissement en dioxygène. L’étude expérimentale complémentaire en régime turbulent des flammes diluées à l’H2O ou au CO2 a permis de mettre en avant l’effet de la vitesse laminaire de flamme sur les structures moyennes et la stabilité des flammes turbulentes. Elle a également permis d’analyser les paramètres (température adiabatique, X(H2O), X(CO2), X(N2), Vitesse de flamme laminaire) ayant un rôle important sur la production des polluants CO et NO. / This PhD thesis deals with the analysis of the effects of exhaust gas recirculation (EGR) through the study of the dilution by carbon dioxide and more particularly of the water steam on dioxygen enriched methane/air flames, in the case of a premixed pressurized combustion encountered in gas turbines. CH4/O2/H2O/N2 pressurized laminar burning velocity measurement were obtained using a spherical flame propagating freely in a closed chamber. The analysis of the experimental results made it possible to check the validity of the kinetic scheme GRIMech.3.0 through numerical calculations of one-dimensional free flames. Further calculations allowed the establishment of a database (laminar burning velocity, Markstein length and Lewis number, adiabatic combustion temperature and flame thickness) as a function of combustion input parameters (temperature, pressure, X(H2O), equivalence ratio and dioxygen enrichment). The additional experimental study under turbulent regime, the flames diluted with H2O and CO2 allowed to highlight the effect of the laminar burning velocity on the average structures and the stability of turbulent flames. It also allowed to analyze the parameters (adiabatic flame temperature, pressure, X(H2O), X(CO2), X(N2), laminar burning velocity) which have an important role in the production of CO pollutants and NO.

La pollution atmosphérique est une problématique urbaine majeure, avec des concentrations de polluants dépassant fréquemment les seuils de recommandations pour la santé. Les véhicules participent fortement à la pollution atmosphérique malgré l’intégration de systèmes de dépollution dans leur ligne d’échappement. L’objectif de ce travail de recherche était de caractériser les émissions primaires à l’échappement des véhicules ainsi que leur évolution physique en champ proche pour mieux comprendre la contribution des émissions primaires liées au trafic à la pollution atmosphérique urbaine. L’évolution des émissions a été étudiée dans une chambre de simulation atmosphérique qui a permis de simuler des conditions atmosphériques contrôlées.La première partie de ce travail était centrée sur les mesures d’émissions à l’échappement des véhicules récents qui sont ou seront majoritaires dans le parc automobile français dans les prochaines années. Pour cela, un échantillon de véhicules regroupant les principales technologies de dépollution commercialisées a été testé. Les gaz d’échappement émis par les véhicules ont été analysés lors de tests sur un banc à rouleau suivant différentes conditions de conduites. Les polluants soumis aux réglementations Européennes ont été mesurés, ainsi que certains composés non-réglementés par les normes Européennes mais dont la dangerosité a été mise en évidence par la communauté scientifique.La deuxième partie de ce travail se concentre sur l’évolution en champ proche des polluants particulaires dans les heures qui suivent leur rejet dans l’atmosphère. L’effet de la dilution soudaine des gaz en sortie de pot d’échappement a été étudié en utilisant une méthodologie innovante de prélèvement directement à l’échappement. Ensuite l’évolution des particules dans les premières heures après leur rejet a été étudiée dans une chambre de simulation atmosphérique de 8 m3, construite spécifiquement dans le cadre de cette thèse pour être couplé au banc à rouleau. / Air pollution is a major urban issue, with pollutant concentrations frequently exceeding health recommendations. Vehicles are highly involved in air pollution despite the integration of pollution control systems. The objective of this research is to characterise the primary exhaust emissions of vehicles and their physical evolution in the near field to better understand the impact of primary emissions related to traffic on urban air pollution. Emissions evolution was studied in an atmospheric simulation chamber with controlled atmospheric conditions. The first part of this work aims to determine the exhaust emissions of recent vehicles that are or will be major in the French car fleet in the coming years. A sample of vehicles grouping the main commercialised depollution technologies was tested on a chassis dynamometer according to different driving conditions and the emissions from their exhaust gas were analysed. The pollutants subject to European regulations were taken into account, as well as compounds not regulated by European standards but whose toxicity has been highlighted by the scientific community.The second part of this work focuses on the near-field evolution of particulate pollutants in the hours following their release into the atmosphere. The effect of the abrupt gas dilution at the end of the exhaust has been studied using an innovative sampling methodology directly at the exhaust of the vehicles. Then the evolution of the particles in the first hours after their rejection was studied in an atmospheric simulation chamber of 8 m3, built specifically within the framework of this thesis to be coupled with the dynamometer.

Les résidus de médicaments font partie des polluants dits « émergents » pour lesquels il n’existe actuellement pas de réglementation quant à leur présence dans l’environnement. Afin d’anticiper un risque éventuel pour l’Homme et les milieux aquatiques il est, entre autres, nécessaire de réaliser un état des lieux de la contamination des systèmes aquatiques par ce type de micropolluants. Dans ce contexte, disposer de données de mesures de qualité (traçables et comparables) constitue un prérequis indispensable pour décider au mieux des politiques à conduire dans ce domaine. L’étude des psychotropes présente un enjeu important d’autant plus qu’il s’agit de molécules abondamment consommées.Les travaux conduits lors de cette thèse avaient deux objectifs principaux. Le premier était de caractériser l’occurrence environnementale de composés psychotropes. Le second objectif était de proposer des outils métrologiques permettant d’assurer l’exactitude, la traçabilité, la comparabilité mais également la représentativité des résultats de mesure.Dans un premier temps, une méthode multi-résidus par SPE-LC-MS² a été développée pour une sélection de composés psychotropes et d’autres médicaments de consommation courante. Les limites de quantification de la méthode étaient de l’ordre du ng.L-1. Cela a permis de caractériser leur occurrence dans différents cours d’eau et rejets de station d’épuration en France. En parallèle, une approche par échantillonnage intégratif a été développée et déployée dans différents sites. Cette stratégie complémentaire a permis d’établir les niveaux d’occurrence des 68 psychotropes et traceurs sélectionnés et de conduire une démarche de hiérarchisation dans le but d’établir une liste restreinte de composés d’intérêt. Enfin, une méthode de référence associant la dilution isotopique à la spectrométrie de masse (DI-MS) a été développée pour l’analyse de 24 psychotropes dans les eaux de surface. Elle se caractérise par des incertitudes élargies (k=2) inférieures à 10%. La mise en oeuvre de cette méthode dans des études environnementales a permis de mettre en évidence l’importance de la contribution de l’incertitude liée à l’échantillonnage par rapport à l’incertitude totale de mesure. / Pharmaceuticals and their residues belong to the so-called “emerging” pollutants for which no current regulation is applied regarding their presence in the environment. Monitoring the contamination of aquatic resources by these kinds of micropollutants is a necessity in order to anticipate potential effects regarding human health and ecosystems. In this context, data quality (traceability and comparability) is compulsory so as to take better decisions regarding policies to be driven. Psychotropic compounds, which are widely consumed, display a great concern in that field.This thesis aimed at characterizing occurrence of psychotropic compounds in the environment and putting forward metrological tools insuring accuracy, traceability, comparability as well as representativity of the measurement results.To that purpose, a SPE-LC-MS² multi-residue method has been developed for a selection of psychotropic compounds and other commonly consumed drugs. Method limits of quantification were in the range of ng.L-1 which enabled to characterize their occurrence in several surface waters and treated wastewaters. Concurrently, usage of integrative samplers was evaluated and applied on the field in different locations. Occurrence levels of 68 selected compounds were established by implementation of this complementary strategy in aquatic systems. Furthermore, results from measurement campaigns were used to rank studied compounds into a short list of interest. Finally, a reference method using isotopic dilution and mass spectrometry (DI-MS) was developed for the characterization of 24 psychotropic compounds in surface waters. Expanded uncertainties (k=2) inferior to 10% were obtained. Last be not least, implementing this method to environmental analysis emphasized the importance of sampling related uncertainties regarding to global measurement uncertainties.

[ES] Desde la irrupción de los vehículos eléctricos en el mercado automotriz como una opción de transporte limpia y asequible, los fabricantes de motores han estado buscando nuevas formas de reducir la huella ambiental de los actuales motores de combustión interna alternativos (MCIA). Hoy en día, la mayoría de las investigaciones en aplicaciones de vehículos de pasajeros se centran en desarrollar aún más los motores de encendido provocado (MEP) para promover una nueva generación de sistemas de propulsión sostenibles y de alto rendimiento. En este contexto, el concepto de encendido de precámara se está convirtiendo en una solución atractiva para aumentar la eficiencia térmica de los futuros MEP para vehículos de pasajeros, debido a su capacidad de acelerar el proceso de combustión. Además, la combinación de esta estrategia de encendido con mezclas diluidas (ya sea con aire o gases de escape) tiene el potencial de mejorar aún más el rendimiento del motor. En particular, en comparación con los sistemas de precámara activa con suministro de combustible auxiliar, la versión pasiva ofrece ventajas evidentes en términos de simplicidad mecánica, ensamblaje y coste. Sin embargo, todavía existen importantes obstáculos relacionados con la comprensión de los aspectos fisicoquímicos fundamentales del concepto (turbulencia, aerodinámica, conversión de energía, dinámica de los chorros, geometría de precámara...), que en última instancia han limitado la integración de esta tecnología en producción. Por lo tanto, esta tesis doctoral pretende extender el nivel de conocimiento de este concepto de encendido mediante el uso de un modelo CFD de última generación, validado con un extenso conjunto de medidas experimentales y siguiendo una metodología especialmente desarrollada para este trabajo de investigación. Los resultados obtenidos se dividieron en tres partes: La primera parte evaluó un MEP monocilíndrico de investigación, representativo de vehículos automóviles, que integraba el concepto de precámara pasiva en condiciones estequiométricas sin dilución. Aquí se evaluó el impacto del punto de operación del motor, el avance del encendido y la geometría de la precámara sobre los procesos físicos y termoquímicos que intervienen en este concepto de combustión. La segunda parte del estudio se centró en caracterizar el concepto en condiciones diluidas con aire y recirculación de gases de escape (EGR). Se analizó en profundidad la evolución del proceso de combustión y la distribución de energía en la precámara y cámara principal para los límites de dilución experimentales. Además, también se evaluó el uso de hidrógeno para ampliar el límite de dilución con aire. La última etapa de la investigación consistió en evaluar una posible aplicación tecnológica de este concepto de encendido a partir de los conocimientos adquiridos. Por ello, se desarrolló una metodología de diseño de precámara que combina herramientas numéricas 0D/1D y CFD. Posteriormente, la metodología fue validada en el banco de ensayos del motor, y la precámara resultante ofreció buenos niveles de rendimiento térmico y fue capaz de extender el límite de dilución con EGR. Con ello, la presente tesis doctoral supone un avance significativo en el campo del análisis del impacto de la integración de sistemas avanzados en MCIA en general, y en MEP en particular, con el objetivo de mejorar sus prestaciones, emisiones o rendimiento, contribuyendo al esfuerzo que está realizando la comunidad científica para mitigar el impacto ambiental del sector del transporte. / [CAT] Des de la irrupció dels vehicles elèctrics en el mercat automotriu com una opció de transport neta i assequible, els fabricants de motors han estat buscant noves maneres de reduir la petjada ambiental dels actuals motors de combustió interna alternatius (MCIA). Hui dia, la majoria de les investigacions en aplicacions de vehicles de passatgers se centren a desenvolupar encara més els motors d'encesa provocada (MEP) per a promoure una nova generació de sistemes de propulsió sostenibles i d'alt rendiment. En aquest context, el concepte d'encesa de precàmera s'està convertint en una solució atractiva per a augmentar l'eficiència tèrmica dels futurs MEP per a vehicles de passatgers, a causa de la seua capacitat d'accelerar el procés de combustió. A més, la combinació d'aquesta estratègia d'encesa amb mescles diluïdes (siga amb aire o productes de la combustió) té el potencial de millorar encara més el rendiment del motor. En particular, en comparació amb els sistemes de precàmera activa amb subministrament de combustible auxiliar, la versió passiva ofereix avantatges evidents en termes de simplicitat mecànica, assemblatge i cost. No obstant això, encara existeixen importants obstacles relacionats amb la comprensió dels aspectes fisicoquímics fonamentals del concepte (turbulència, aerodinàmica, conversió d'energia, dinàmica d'ejecció, geometria de precàmera...), que en última instància han limitat la integració d'aquesta tecnologia a la producció en sèrie. Per tant, aquesta tesi doctoral pretén estendre el nivell de coneixement d'aquest concepte d'encesa mitjançant l'ús d'un model CFD d'última generació, validat amb un extens conjunt de mesures experimentals i seguint una metodologia especialment desenvolupada per a aquest treball de recerca. Els resultats obtinguts es divideixen en tres parts. La primera part estudia un MEP monocilíndric d'investigació, representatiu dels vehicles actuals d'automoció, que integra el concepte de precàmera passiva en condicions estequiomètriques sense dilució. Ací s'avalua l'impacte del punt d'operació del motor, l'avanç de l'encesa i la geometria de la precàmera sobre els processos físics i termoquímics que intervenen en aquest concepte de combustió. La segona part de l'estudi se centra a caracteritzar el concepte en condicions diluïdes amb aire i recirculació de gasos produïts per la combustió (EGR). S'analitza en profunditat l'evolució del procés de combustió i la distribució d'energia en la precàmera i en cambra principal per als límits de dilució experimentals. A més, també s'avalua l'ús d'hidrogen per a ampliar el límit de dilució amb aire. L'última etapa de la investigació consisteix a avaluar una possible aplicació tecnològica d'aquest concepte d'encesa a partir dels coneixements adquirits. Per això, es desenvolupa una metodologia de disseny de precàmera que combina eines numèriques 0D/1D i CFD. Posteriorment, la metodologia és validada al banc d'assajos del motor, on la precàmera resultant ofereix bons nivells de rendiment tèrmic i és capaç d'estendre el límit de dilució amb EGR. Amb això, la present tesi doctoral suposa un avanç significatiu en el camp de l'anàlisi de l'impacte de la integració de sistemes avançats en MCIA en general, i en MEP en particular, amb l'objectiu de millorar les seues prestacions, emissions o rendiment, contribuint a l'esforç que està realitzant la comunitat científica per a mitigar l'impacte ambiental del sector del transport. / [EN] Since the irruption of electric vehicles in the automotive market as a clean and affordable transportation option, engine manufacturers have been looking for new ways to reduce the environmental footprint of current internal combustion engines (ICE's). Nowadays, most of the research efforts in passenger car applications focus on further developing spark-ignition (SI) engines to promote a new generation of high-performance and sustainable powertrains. In this context, the pre-chamber ignition concept is becoming an attractive solution to increase the thermal efficiency of future light-duty SI engines, due to its inherent capability of enhancing the combustion process. Moreover, combining this ignition strategy with diluted mixtures (either with air or exhaust gases) has the potential to further improve the engine performance and reduce pollutant emissions. In particular, compared to active pre-chamber systems with an auxiliary fuel supply, the passive version provides advantages in terms of mechanical simplicity, packaging and cost-effectiveness. However, there are still major hurdles related to the understanding of the fundamental physicochemical aspects of the concept (turbulence, scavenging, energy conversion, jet dynamics, pre-chamber geometry...), that ultimately have limited the integration of this technology into production vehicles. Therefore, this doctoral thesis intends to fill these knowledge gaps by using a state-of-the-art CFD model, validated with an extensive set of engine tests and following a simulation methodology specially developed for this research work. The obtained results were divided into three parts: The first part evaluated a research single-cylinder SI engine, representative of light-duty applications, operating with the passive pre-chamber system in un-diluted stoichiome\-tric conditions. Here, the impact of the engine operating point, spark timing and pre-chamber geometry over the physical and thermochemical processes that are involved in this combustion concept were evaluated. The second part of the study focused on characterizing the concept in diluted conditions with air and exhaust gas re-circulation (EGR). The combustion evolution and energy distribution in the pre-chamber and main chamber for the experimental dilution limits were deeply analyzed. In addition, the use of hydrogen to extend the air-dilution limit was also assessed. The final part of the investigation consisted in developing a potential technological application of this ignition concept from the acquired knowledge. Therefore, a pre-chamber design methodology combining 0D/1D and CFD numerical tools was developed and validated in the engine test bench. The resulting pre-chamber offered good levels of thermal efficiency and was able to extend the EGR dilution limit. This doctoral thesis represents a significant advancement in the frame of analyzing the impact of advanced ignition systems and their integration in ICE's in general, and in SI engines in particular, with the aim of improving the global features of these powerplants (efficiency and emissions), contributing to the effort that the scientific community is carrying out to mitigate the environmental impact of the transportation sector. / Barbery Avila, II. (2023). CFD Modelling and Analysis of the Passive Pre-Chamber Ignition Concept for Future Generation Spark-Ignition Engines [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/193035

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The Constitutional Court in the Republic of South African indicated in 2006 (Laugh It Off Promotions CC v SAB International (Finance) BV t/a Sabmark International (Freedom of Expression Institute as amicus curiae), 2006 (1) SA 144 (CC)) that a senior trademark cannot be provided with anti-dilution protection if the senior trademark cannot demonstrate a probability of substantial economic harm. In the United States of America, legislation (Trademark Dilution Revision Act of 2006) corrected an earlier Supreme Court decision (Moseley v Victoria's Secret Catalogue, Inc., 537 U.S. 418 (2003)), and as a result evidence of a probability of dilution is now required to provide a senior trademark with anti-dilution protection. Senior trademarks experienced mixed success in courts in the Republic of South Africa as well as the United States of America when requesting anti-dilution protection. The reason is that when empirical evidence is offered of trademark dilution the nature of the evidence is usually limited and the method of obtaining it is often flawed. The response of brand managers to trademark infringement also seems to be limited to decisions contemplating litigation. Therefore, to assist both the legal and marketing fraternity when trademark infringement is thought to occur, this study investigates the nature and extent of trademark dilution. A literature review revealed the elements and forms (tarnishing and blurring) of trademark dilution and the motivation for using the concept ‘brand’ and the construct ‘brand equity’ to conceptualise trademark value. The limitations of previous research in measuring trademark dilution and commentary on court decisions provided the basis of the conceptualisation of trademark dilution as an undesirable effect on customer-based brand equity, operationalised as brand attitude. Brand attitude is a higher level brand value creator and five sub-components (affect, cognition, attitude valence and stability, attitude accessibility, purchase intention) were identified that measures brand attitude accurately. Brand attitude is also preceded by brand familiarity and leads to brand loyalty. Furthermore, brand attitudes can also be explained according to four types of decision-making processes: the type of decisions (high and low involvement) and type of motivations (informational and transformational). The purpose of this study was to investigate the nature and extent of trademark dilution, (tarnishing and blurring) on components of customer-based brand equity. The study used an experimental research strategy and an electronic survey instrument (Qualtrics) with self-administered questionnaires. Six hypotheses were formulated to assess whether trademark tarnishing and blurring had an effect on any component of customer-based brand equity when trademarks/brands were considered collectively and individually. The study was designed as a 3 x 2 x 2 factorial experiment. It consisted of three factors (type of dilution; type of decision; type of motivation) with different levels (undiluted/tarnish/blur; high involvement/low involvement; informational/transformational). Twelve different questionnaires were administered to a convenience sample of 3 441 potential respondents. The data generated by the 12 questionnaires was analysed using ANOVA and Mann-Whitney U tests. The results suggested that trademark tarnishing did have statistically significant effects on components of customer-brand equity as far all trademarks/brands were concerned and that the effect of trademark tarnishing and blurring were different when all trademarks/brands were considered together. Tarnishing and blurring had statistically significant effects on components of customer-based brand equity when individual trademarks/brands were considered, but the effect seemed to be specific to the type of decision (high/low involvement) taken and not the type of motivation (informational/transformational) involved. Tarnishing and blurring, when compared, had different and similar, but varying in intensity, effects on components of customer-based brand equity for individual trademarks/brands. Tarnishing and blurring, when considered separately, had different and similar, but varying in intensity, effects on components of customer-based brand equity. The study made a theoretical contribution which should be of value to members of the legal and marketing fraternity. The study showed in the first instance that trademark tarnishing and blurring are independent constructs that had different or similar, but varying in intensity, effects on components of customer-based brand equity. The effect of trademark dilution, tarnishing and blurring, is not limited to brand recall and recognition and brand attitude accessibility. Trademark tarnishing also had different or similar, but varying in strength, effects on individual trademarks/brands, as did trademark blurring. The type of decision (high or low) and type of motivation (informational or transformational) therefore play a role in the unique effect trademark tarnishing or blurring will have on components of customer-based brand equity. Secondly, the effect of trademark tarnishing and blurring may not be unfavourable by implication. In fact, blurring had a positive effect on components of customer-based brand equity, at least after a single exposure. This finding implies that trademark tarnishing has a more severe and faster effect on customer-based brand equity compared to trademark blurring. A brand manager will, as a result of the study, know how to respond, if at all, when a junior mark emerges that is similar to their senior trademark and seemingly dilutes the senior trademark. An attorney whose client requests anti-dilution protection will know, as a result of the study, whether litigation is indeed the answer to the problem. The study provides insight, not only regarding the nature of trademark dilution, as explained by the impact of trademark tarnishing and blurring on specific components of customer-based brand equity, but also regarding the extent of trademark dilution. Trademark dilution has an effect on trademarks/brands, but the effect, be it in respect of a specific component or the intensity of the effect on the component, may not be what is expected. Based on the results of this study several recommendations can be offered to brand managers and trademark attorneys. Brand managers (senior trademarks) should not respond to junior marks using their brands (senior trademarks) without first assessing the nature and extent of the effect of the junior mark on the senior trademark’s customer-based brand equity. Similarly, attorneys should also first examine the nature and extent of trademark dilution and advise their clients accordingly. Once the nature and extent of trademark dilution have been determined, a brand manager can customise his response according to the component of customer-based brand equity affected as well as the intensity of the effect. Attorneys can support at least part of their arguments to obtain anti-dilution protection for their clients, on very exact indications of the effect of use by a junior mark on customer-based brand equity. / AFRIKAANSE OPSOMMING: Die Konstitusionele Hof van die Republiek van Suid-Afrika het in 2006 (“Laugh it Off Promotions CC vs SAB International (Finance) BV t/a Sabmark International (Freedom of Expression Institute as amicus curiae),” 2006 (1) SA 144 (CC)) bevind dat ‘n senior handelsmerk nie anti-skendingsbeskerming kan geniet tensy die senior handelsmerk ‘n waarskynlikheid van wesenlike finansiële skade kan demonstreer nie. In die Verenigde State van Amerika het wetgewing ‘n Hooggeregshof-uitspraak (“Moseley v Victoria’s Secret Catalogue, Inc.,” 537 U.S. 418 (2003)) gekorrigeer sodat sederdien slegs bewys van ‘n waarskynlikheid van skending nou benodig word vir ‘n senior handelsmerk om anti-skendingsbeskerming te kan geniet. Senior handelsmerke het gemengde welslae in beide die Republiek van Suid-Afrika sowel as die Verenigde State van Amerika behaal wanneer hulle anti-skendingsbeskerming versoek het omrede die empiriese bewyse wat normaalweg aangebied is, beperkend van aard was en die data-insamelingsmetode gebrekkig. Die reaksie van handelsmerkbestuurders op handelsmerk-oortreding was tot dusver beperk tot besluite ten gunste van litigasie al dan nie. Derhalwe ondersoek hierdie studie die aard en omvang van handelsmerk-skending om sodoende beide die regskundige en bemarkingsgemeenskappe te ondersteun wanneer handelsmerk-oortreding vermoed word. ‘n Literatuur oorsig het die elemente en vorme (besmetting en verdowwing) van handelsmerk-skending geidentifiseer asook die motivering om die konsep van ‘handelsmerk’ en die konstruk van ‘handelsmerkwaarde’ te gebruik. Die beperkings van vorige navorsing om handelsmerk-skending te meet en kommentaar op hofbeslissings het die basis van die voorstelling van handelsmerk-skending as ‘n ongewenste effek op kliënt-gebaseerde handelsmerkwaarde neergelê en dit geoperasionaliseer as handelsmerk-ingesteldheid. Handelsmerk-ingesteldheid is ‘n hoë-vlak handelsmerkwaardeskepper en vyf subkomponente (gevoelsinhoud/emosie; denke/kennis; polariteit en stabiliteit van ingesteldheid; ingesteldheidstoeganklikheid/reaksie latentheid; aankoopvoorneme) is geïdentifiseer wat handelsmerk-ingesteldheid akkuraat meet. Handelsmerk-ingesteldheid word voorafgegaan deur handelsmerk-bekendheid en gevolg deur handelsmerk-lojaliteit. Verder kan handelsmerk-ingesteldheid ook verklaar word aan die hand van vier soorte besluitnemingsprosesse: die tipe besluit (hoë betrokkenheid of lae betrokkenheid) en die tipe motivering (informatief of transformerend). Die doel van die studie was om die aard en omvang van handelsmerk-skending, (besmetting en verdowwing) op die komponente van kliënt-gebaseerde handelsmerkwaarde te ondersoek. Die studie het ‘n eksperimentele navorsingstrategie gevolg en van ‘n elektroniese opname-instrument (Qualtrics) met self-geadministreerde vraelyste gebruik gemaak. Ses hipoteses is geformuleer om vas te stel of besmetting of verdowwing ‘n effek op enige komponent van kliënt-gebaseerde handelsmerkwaarde het wanneer alle handelsmerke gesamentlik beskou word sowel as afsonderlik. Die studie was ontwerp as ‘n 3 x 2 x 2 faktoriale eksperiment. Dit het bestaan uit drie faktore (tipe skending; tipe besluit; tipe motivering) met verskillende vlakke (onbenadeel/besmet/verdof; hoë betrokkenheid/lae betrokkenheid; informatief/transformerend). Twaalf verskillende vraelyste is aan ‘n geriefsteekproef van 3 441 moontlike respondente gestuur. Die data word deur die 12 vraelyste gegenereer is met behulp van ANOVA en Mann Whitney U toetse ontleed. Die resultate het aangetoon dat besmetting ‘n statisties betekenisvolle effek op die komponente van kliënt-gebaseerde handelsmerkwaarde het wanneer die handelsmerke gesamentlik beskou word, asook dat die effek van besmetting en verdowwing verskillend is wanneer al die handelsmerke gesamentlik beskou word. Bemetting en verdowwing het statisties betekenisvolle effekte op die komponente van handelsmerkwaarde wanneer handelsmerke afsonderlik beskou word, maar die effek blyk verwant aan die tipe besluit (hoë betrokkenheid/lae betrokkenheid) te wees en nie aan die tipe motivering (informatief/transformerend) nie. Besmetting en verdowwing, wanneer dit vergelyk word, het verskillende of soortgelyke, maar veranderend invloede ten opsigte van intensiteit, effekte op die komponente van kliënt-gebaseerde handelsmerkwaarde. Die studie lewer ‘n teoretiese bydrae gelewer aan lede van die regskundige-en bemarkingsgemeenskappe. Die studie het ten eerste getoon dat handelsmerk-besmetting en –verdowwing onafhanklike konstrukte is wat verskillende of soortgelyke, maar veranderend in intensiteit, effekte op kliënt-gebaseerde handelsmerkwaarde het. Die effek van handelsmerk-skending, besmetting en verdowwing, is nie net beperk tot handelsmerk-herroeping en -herkenning en handelsmerk-ingesteldheidstoeganklikheid nie. Handelsmerk-besmetting het ook verskillende of soortgelyke, maar verskillend in intensiteit, effekte op die handelsmerke afsonderlik, wat ook geld in handelsmerk-verdowwing. Die tipe besluit (hoë betrokkenheid of lae betrokkenheid) en tipe motivering (informatief of transformerend) speel derhalwe ‘n rol in die unieke effek wat besmetting of verdowwing op die komponente van kliënt-gebaseerde handelsmerkwaarde het. Tweedens is die effek van besmetting en verdowwing nie noodwendig ongunstig nie. Trouens, verdowwing het ‘n versterkende effek op sommige komponente van kliënt-gebaseerde handelsmerkwaarde gehad, ten minste ná ‘n enkele blootstelling. Dit impliseer dat besmetting ‘n veel erger en vinniger effek op kliënt-gebaseerde handelsmerkwaarde as verdowwing het. ‘n Handelsmerkbestuurder sal na aanleiding van die studie weet hoe om te reageer, indien enigsins, wanneer ‘n junior merk verskyn wat soortgelyk aan die senior handelsmerk is. ‘n Prokureur wie se kliënt anti-skendingsbeskerming versoek sal weet, na aanleiding van die studie, of litigasie inderdaad die antwoord op die probleem is. Die studie verskaf insig, nie net ten opsigte van die aard van handelsmerkskending soos beskryf deur die impak van handelsmerkbesmetting en –verdowwing op sekere komponente van kliënt-gebaseerde handelsmerkwaarde nie, maar ook ten opsigte van die omvang van handelsmerkskending. Handelsmerkskending het ‘n effek op handelsmerke, maar die effek, of dit op ‘n sekere komponent of op die intensiteit van die effek op die kompenent mag wees, is moontlik anders as wat verwag is. Gabaseer op die resultate kan verskeie aanbevelings aan handelsmerkbestuurders en handelsmerkprokureurs gemaak word. Handelsmerkbestuurders (senior handelsmerke) behoort nie te reageer op junior merke wat hul merk (senior handelsmerk) gebruik sonder om die aard en omvang van die effek van die junior merk op die senior handelsmerk se kliënt-gebaseerde handelsmerkwaarde te bepaal nie. Eweneens behoort handelsmerkprokureurs eers die aard en omvang van die handelsmerkskending te bepaal en hul kliënte dienooreenkomstig adviseer. Sodra die aard en omvang van handelsmerkskending bepaal is, kan ‘n handelsmerkbestuurder sy reaksie volgens die geaffekteerde komponent van die handelsmerk, sowel as die intensiteit daarvan, aanpas. Prokureurs kan ten minste sommige van hul argumente om anti-skendingsbeskerming vir hul kliënte te verkry, ondersteun deur baie duidelike aanduidings van die effek van die gebruik van ‘n junior merk op kliënt-gebaseerde handelsmerkwaarde.