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Direct injection spark ignition (DISI) engines are the next generation of gasoline fuelled engines. Their greater fuel economy and reduced CO2 emissions compared with port fuel injection (PFI) engines has led to their popularity. However, DISI engines produce a greater number of particulate matter (PM) emissions than PFI engines. Concern over the health effects of PM emissions, and forthcoming European legislation to regulate them from gasoline powered vehicles has led to an increased interest in the study of PM formation, measurement, and characterisation. A model was developed by Aikawa et al, the PM index, correlating PM emissions with fuel composition. PM emissions are thought to be linked both to the vapour pressure (VP) and the double bond equivalent (DBE) of the components of the fuel. However, there was no independent control of these parameters and the study was undertaken on a PFI engine. In this thesis, experiments have been conducted to validate this model and extend it, as the PN index, to DISI engines. Fuels have been designed using Raoult’s law and UNIFAC (with careful consideration of octane number) such that the DBE and VP of the fuel mix could be varied independently. The design of the fuels was such that the component parts would co-evaporate upon injection into the cylinder, ensuring a homogeneous mixture of the components at the point of ignition. The PN index has been tested on a single cylinder engine, at a matrix of test points, using these model fuels, and their PM emissions have been analysed using a Cambustion DMS500. The results show that the PN index is followed closely using model fuels, provided that these model fuels contain a ‘light-end’ (in this case 5 % v/v n-pentane). Imaging of in-cylinder evaporation and in-cylinder measurement of hydrocarbons shows how the composition of model fuels affects their PM emissions. The PN index has also been tested using commercial fuels on a single cylinder engine and a Jaguar V8 engine; the results again show that the PN index is also an excellent predictor of PN emissions for market fuels from both of these engines. PN emissions have been evaluated from two fuels representing the EU5 reference fuel specification, developed using the PN index to give a difference in PM emissions. Testing these fuels on both a single cylinder engine and a Jaguar V8 engine has shown up to a factor of three variation in observed PN emissions. This has important implications for forthcoming European emissions legislation. The results of these tests were fed into the recommendations for the EU6 reference fuel specification. The PN index has also been investigated in a Jaguar V6 engine with five different fuels with a spread of calculated PN indices over a simulated NEDC. Here the PN emissions have been measured using two PN, and one PM instrument and the results compared. The results show that the trends of the PN index are followed, but not as closely as predicted. Detailed analysis shows that this discrepancy is due to other effects, for example cold start, dominating the PN emissions in certain phases. PN emissions have been measured from a highly boosted engine at a variety of operating points using 14 different fuels. It has been shown that for a large variety of engine operating parameters PN emissions from highly boosted engines behave as expected. When changing the fuels, the results show that a variation of over three orders of magnitude can be observed. The predictions of the PN index are inconclusive however, with further work suggested to fully evaluate the PN index on highly boosted engines.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Amostras de solos, minério de ferro e material particulado atmosférico foram analisadas com o objetivo de se investigar as diferentes propriedades físico-químicas de seus compostos ferruginosos e, dessa forma, identificar se as fontes de emissão do material particulado atmosférico da Região Metropolitana de Belo Horizonte são de origem natural, como por exemplo, da ressuspensão de partículas de solo, ou de origem antrópica, proveniente dos processos de mineração e/ou beneficiamento do minério de ferro. O modelo numérico denominado Industrial Source Complex - Short Term Version 3 foi utilizado para simular os processos de dispersão atmosférica do material particulado emitido em decorrência das atividades de mineração de ferro de empreendimentos localizados no Quadrilátero Ferrífero de Minas Gerais. Os resultados dessas simulações numéricas auxiliaram na escolha da localização dos pontos de amostragem de material particulado, uma vez que indicaram os pontos de maiores concentrações desse poluente na atmosfera da área em estudo. As amostras de material particulado foram coletadas com um amostrador de ar de grande volume (Hi-Vol). Todas as amostras foram caracterizadas por fluorescência de raios-X, difração de raios-X, magnetometria e espectroscopia Mössbauer do 57Fe. Os resultados dessas análises composicionais e estruturais mostraram que as amostras de solo analisadas possuem altas concentrações de silício, alumínio, material orgânico e baixos teores de ferro na forma de óxidos de ferro com baixa cristalinidade. Por outro lado, as amostras de minério de ferro apresentaram altos teores de ferro, predominantemente na fase de hematita com elevado grau de pureza e cristalização. As amostras de material particulado atmosférico apresentaram ferro, na forma predominante de hematita, silício, alumínio e cálcio em sua composição principal. Por meio da espectroscopia Mössbauer foi possível identificar características distintas entre a estrutura hiperfina do 57Fe da hematita presente nas amostras de minério de ferro e da hematita presente nas amostras de solo, contribuindo, portanto, para a identificação e quantificação das espécies químicas do minério nas amostras de material particulado atmosférico. Os resultados finais evidenciaram que nas amostras de particulados atmosféricos das regiões localizadas mais próximas aos empreendimentos de mineração, os teores de hematita provenientes do minério de ferro são maiores, se comparados aos teores obtidos naquelas amostras de particulados de locais mais distantes desses empreendimentos. Constatou-se também que mesmo as regiões mais distantes dos empreendimentos minerários não estão isentas desses impactos atmosféricos causados pela emissão de material particulado, demonstrando, portanto, a necessidade do controle efetivo das emissões de material particulado das atividades relacionadas à mineração de ferro no estado de Minas Gerais. / Samples of soil, iron ore and airborne atmospheric particulate matter were analysed with the main goal of investigating the different physicochemical properties of their ferruginous compounds and thereby identifying whether the sources of the particulate matter in the Metropolitan Area of Belo Horizonte are of natural origin, such as, resuspension of particles from soil, or due to anthropogenic origin arising from mining and processing of iron ore. The Industrial Source Complex - Short Term model (ISCST3) was used to simulate the atmospheric dispersion processes of particulate matter emitted as a result of iron mining activities in the Iron Quadrangle of Minas Gerais. The results of these numerical simulations aided in determining the location with highest concentration of particulate matter in the study area. Airborne particulate matter was then collected in each place using high volume air samplers (Hi-Vol). All samples were characterized by X-ray fluorescence, powder X-ray diffraction, magnetometry and 57Fe-Mössbauer spectroscopy. The results of compositional and structural analyzes showed that soil samples are rich in quartz, aluminum, organic material and have low contents of iron, mainly iron oxide with low crystallinity. The samples of iron ore, in turn, have high concentration of iron, predominantly in the hematite phase with high purity and crystallization. The samples of atmospheric particulate matter have iron, predominantly hematite, as well as quartz, aluminum and calcium. Mössbauer spectroscopy permitted the quantification of different characteristics based on the hyperfine structure of 57Fe of the hematite in iron ore samples and of the hematite in soil samples. These results contributed to the identification and quantification of the different hematite phases in the particulate material samples. The final results showed that the hematite content from iron ore present in the particulate matter from samples collected in regions located close to mining enterprises are higher those present in samples from more distant places, so that the direct influence of the extraction of iron ore upon the composition of the atmospheric particulate matter could be clearly proved. It could be also demonstrated that even regions more distant from the mining activities are not exempt from these atmospheric impacts indicating the need for effective control of particulate matter emissions from activities related to iron mining in the State of Minas Gerais.

The control of particle emissions from an oil refinery is often difficult, due to changing operational conditions and the limited range of available treatment options. Excessive particle emissions have often been attributed start up problems with Fluidized Catalytic Cracker Units (FCCU) and little information is available regarding the exact composition and nature of these excessive emissions. Due to the complex nature of a FCCU, it has in the past been difficult to identify and control emissions, without the use of expensive end of pipe technologies. An Australian Oil Refinery, concerned with their catalyst emissions, sponsored this study of FCCU particle emissions. Due to the industrial nature of the project, a holistic approach to the management of emissions was taken, instead of a detailed investigation of a single issue. By looking at the broader range of issues, practical and useful outcomes can be achieved for the refinery. Initially, detailed emissions samplings were conducted to investigate the degree of particle emissions under start up conditions. Stack emissions were collected during a standard start up, and analysed to determine the particle size distribution and metal concentration of the emitted material. Three distinct stages of emissions were discovered, initially a high concentration of larger particles, followed by a peak in the very fine particles and finally a reduction of particle emissions to a more steady or normal operational state. The variation in particle emissions was caused by operational conditions, hardware design and catalyst characteristics. Fluctuations in the gas velocity through the system altered the ability of the cyclones to collect catalyst material. Also, the low bed level allowed air bypass to occur more readily, contributing to the increased emissions levels seen during the initial stage of the start up. Reduced fluidity characteristics of the circulating catalyst also affected the diplegs operations, altering the collection efficiency of the cyclone. During the loading of catalyst into the system, abraded material was quickly lost due to its particle size, contributing to fine particle emissions levels. More importantly, thermal fracturing of catalyst particles occurred when the cold catalyst was fed into the hot regenerator. Catalyst particles split causing the generation of large amounts of fine particle material, which is easily lost from the system. This loading of catalyst directly linked to the period of high concentration of fine particles in the emissions stream. It was found that metals, and in particular iron, calcium and silicon form a thick layer on the outside of the catalyst, with large irregular shaped metal ridges, forming along the surface of the particle. These ridges reduce the fluidity of the catalyst, leading to potential disruptions in the regenerator. In addition to this, the metal rich ridges are preferentially removed via attrition, causing metal rich material to be emitted into the atmosphere. To overcome these high particle emissions rates from the FCCU the refinery should only use calcinated catalyst to reduce the influence of thermal process and particle fracture and generation. Although the calcinated catalyst can fracture when added to the system, it is far less than that obtained with uncalicinated catalyst. To further reduce the risk of particle fracture due to thermal stresses the refinery should consider reducing the temperature gradients between the hot and cold catalyst. Due to the economics involved with the regenerator, possible pre-warming of catalyst before addition into system is the preferred option. This pre-heating of catalyst should also incorporate a controlled attrition stage to help remove the build up of metals on the surface of the particles whilst allowing this material to be collected before it can be released into the atmosphere. The remove of the metal crust will also improve the fluidity of the system and reduce the chance of catalyst blockages occurring. Finally, modelling of the system has shown that control of key parameters such as particle size and gas velocity are essential to the management of air emissions. The refinery should look at adjusting start up procedures to remove fluctuations in these key parameters. Also the refinery should be careful in using correlation found in the literature to predicted operational conditions in the system as these correlations are misleading when used under industrial situations.

Εξ’ αιτίας της ραγδαίας αύξησης στη χρήση σύνθετων υλικών, στην παρούσα εργασία ασχοληθήκαμε με σύνθετο υλικό μήτρας εποξικής ρητίνης και ενίσχυσης κόκκους αλουμινίου με μέση διάμετρο 63 μm. Σκοπός της έρευνας αυτής είναι κατά πρώτον να μελετήσει τη συμπεριφορά του συνθέτου σε στατική κάμψη αναλόγως της κατά βάρος περιεκτικότητά του σε κόκκους και να συγκρίνει τα πειραματικά αποτελέσματα με αντίστοιχες θεωρητικές προβλέψεις και κατά δεύτερον να μελετήσει την επίδραση βλάβης λόγω ύπαρξης εγκοπής ή θερμικής κόπωσης στην υποβάθμιση του σύνθετου υλικού και να προβλέψει την παραμένουσα μηχανική συμπεριφορά χρησιμοποιώντας το μοντέλο R.P.M. Τρία διαφορετικά μοντέλα πρόβλεψης, ανεπτυγμένα απ’ το CMG (Composite Material Group) του Πανεπιστημίου Πατρών, θα εφαρμοστούν για τις προβλέψεις και δύο απ’ αυτά θα συγκριθούν και με άλλα μοντέλα ανεπτυγμένα από άλλους ερευνητές. Κατ’ αρχήν, για τον υπολογισμό της μέγιστης τάσης εφαρμόστηκε το μοντέλο του τμηματικού κόκκου. Σύμφωνα με το μοντέλο αυτό, ο κόκκος χωρίζεται σε άπειρο αριθμό ινών και σύμφωνα με την θεωρία του Cox μπορεί να υπολογιστεί η μέση τάση που ασκείται σε κάθε ίνα του κόκκου. Στη συνέχεια, για τον υπολογισμό του μέτρου ελαστικότητας συναρτήσει της κατά βάρους περιεκτικότητας σε κόκκους αλουμινίου εφαρμόστηκε το μοντέλο της μεσοφάσης. Το μοντέλο αυτό λαμβάνει υπόψιν την ύπαρξη μιας τρίτης φάσης ανάμεσα στις δύο κύριες (μήτρα-ενίσχυση) και η οποία αποτελεί μια σημαντική παράμετρο επίδρασης στη συμπεριφορά οποιουδήποτε σύνθετου υλικού. Τέλος, στις περιπτώσεις της ύπαρξης εγκοπής και της θερμικής κόπωσης εφαρμόστηκε το μοντέλο R.P.M. Το μοντέλο αυτό μπορεί να εφαρμοστεί για την περιγραφή της υποβάθμισης των ιδιοτήτων των υλικών μετά από βλάβη και στη συγκεκριμένη εργασία εφαρμόστηκε για να περιγράψει τις μεταβολές στην μέγιστη τάση του υλικού και στο μέτρο ελαστικότητάς του συναρτήσει του μήκους εγκοπής ή του αριθμού των θερμικών κύκλων. / -

19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 1983" Fei Tang. 12/19/2004. Report is also available in paper and microfiche from NTIS.

Le transport routier est responsable d’une part des émissions de particules fines, notamment dans les grandes agglomérations. Celles-ci ayant des répercussions graves sur la santé humaine et l’environnement, des normes d’émissions des véhicules de plus en plus strictes sont mises en place. Des limites en nombre de particules sont imposées et une obligation de connaitre l’état de santé des organes de post-traitement des gaz d’échappement est également entrée en vigueur (On-Board Diagnostic : OBD).Les capteurs résistifs ont montré de bons résultats pour la mesure de la concentration massique des particules et ont l’avantage d’être simples à mettre en oeuvre, robustes et peu onéreux. Le principe de fonctionnement du capteur est basé sur la mesure de la conductance entre des électrodes de platine. Celle-ci augmente avec le dépôt de suies.L’objectif de ce travail de thèse est de parvenir à déterminer les paramètres clés qui affectent la réponse du capteur. Trois flux de suies présentant des distributions en taille différentes ont été sélectionnés et caractérisés. Un quatrième flux de suies a permis d’appréhender l’impact d’une concentration massique inférieure. La réponse du capteur à ces différents flux de suies a été étudiée. Nous avons montré que la sensibilité et le temps de réponse du capteur sont optimaux pour une tension de polarisation donnée entre les deux électrodes dont la valeur dépend de la distribution en taille des suies. Ce phénomène a été expliqué par les propriétés électriques différentes des suies et modélisé par un équilibre entre accumulation et combustion par effet Joule des suies déposées permettant de simuler la réponse temporelle du capteur. / Road transport contributes to a part of the particulate matter emissions, especially in big cities. Due to the negative effect of these pollutants on the human health and environment, more and more stringent emission standards for automotive are applied. These emissions are now limited in number of particles per kilometer and the vehicle need to indicate when there is some failure of the systems of depollution (OBD: On-Board diagnostic).Resistive sensors have shown good results to measure soot particles mass concentration. They have advantage of being a simple and robust technology that can be easily manufactured at a cheap price. The sensor principle consists of conductance measurement between two platinum electrodes. Conductance increases with soot deposition. This work aims to define the key parameters that affect the sensors response. Three particles flow with different particles size distributions (centered at 90, 70 and 50 nm) were used and characterized. A fourth flow was used to see the impact of a lower mass concentration. The sensor response exposed to these different flows was studied. It was shown that the sensor sensibility and response times are optimal for a given polarization voltage between the electrodes whose value depends on the size distribution. This phenomenon was explained by the different electrical properties of the soot particles and modeled by equilibrium of soot accumulation and their combustion by Joule heating that permitting to simulate the sensor temporal response.

Die gesundheitsschädliche Wirkung unreiner Luft ist Gegenstand unzähliger Studien und wurde bereits hinreichend nachgewiesen. Der Straßenverkehr ist dabei eine der wesentlichsten Schadstoffquellen, denen der Mensch im Alltag ausgesetzt ist. Ziel dieser Arbeit ist es, die Schadstoffbelastung von Nutzern des Straßenverkehrs vertiefend abzubilden. Im Rahmen eines Literaturreviews werden insgesamt 50 wissenschaftliche Studien analysiert. Obwohl sich viele Studien mit dem Vergleich der Verkehrsmittel bezüglich der Immissionsexposition auseinandersetzen, widersprechen sich ihre Ergebnisse je nach Schadstoff regelmäßig hinsichtlich der Reihenfolge der Verkehrsmittel oder auch grundsätzlich bezüglich der Signifikanz der Verkehrsmittelwahl. Ursache dafür sind die zahlreichen Einflussfaktoren, die sich von Arbeit zu Arbeit unterscheiden und eine Vergleichbarkeit der Messergebnisse stark erschweren. Trotz einer steigenden Anzahl an Studien zum Thema mangelt es den Messmethoden an einem strengen Qualitätsstandard sowie einer ausführlichen Dokumentation der Messbedingungen. Eine Verallgemeinerung und Vergleichbarkeit der Forschungsergebnisse untereinander ist damit bislang nicht gewährleistet. Die Betrachtung der Luftqualität bildet die wissenschaftliche Grundlage, um Grenzwertüberschreitungen aufzuspüren, Gegenmaßnahmen zu erarbeiten und diese auf ihre Wirksamkeit zu kontrollieren. Die Werte stationärer Messeinrichtungen geben dabei ein nur unzureichend genaues Bild über die Immissionen, denen die Nutzer des Straßenverkehrs ausgesetzt sind. Um ein realistischeres Bild über die Immissionsbelastung von Verkehrsteilnehmern zu gewinnen, wird mittels eines mobilen Messgeräts die PM10-Belastung für Radfahrer in Teilen des Dresdner Straßennetzes bestimmt. Dabei wird deutlich, dass die gemessene Schadstoffkonzentration sowohl räumlich innerhalb einer Messstrecke als auch zeitlich im Laufe des Tages variiert. Um den weitestgehend emissionsarmen Rad- und Fußverkehr weiter zu fördern und auszubauen, ist es nötig, die Schadstoffbelastung dieser Verkehrsteilnehmer noch besser zu verstehen und quantifizieren zu können. Nur dann sind Verkehrsplaner und Entscheidungsträger in der Lage, eine Infrastruktur zu schaffen, die ihre Nutzer so wenig wie möglich gesundheitlich beeinträchtigt.