Current methods of solar-grade silicon (SG-Si) production are energy intensive and costly. The possibility of using metallurgical techniques for refining metallurgical-grade Si (MG-Si) to SG-Si has been investigated. The main steps in the metallurgical refining route include alloying with copper to produce a 50-50wt% Cu-Si alloy, controlled solidification, crushing, and acid leaching. The controlled solidification process involved 5 variations to determine the best process to maximize Si dendrite agglomeration in the sample and produce the purest Si. This was determined by using various techniques, such as: optical imaging, dendrite analysis, EPMA and SEM analysis and ICP analysis. The crushing and acid leaching steps were carried out to remove the unwanted Cu3Si eutectic from the pure Si dendrite phase. Upon completion of the analysis techniques, the optimal cooling method was determined to be the top cooled, 0.5°C/min sample.

Mūsų gyvenamoji aplinka - gyvoji ir negyvoji gamta yra labai trapi ir pažeidžiama. Tarp daugelio cheminių teršalų ypatingą vietą užima sunkieji metalai. Jie pasižymi ilgalaikiu ir įvairiapusišku toksiniu poveikiu, keliančiu rimtą grėsmę gyvąjai gamtai ir žmonių sveikatai, o jų migracijos aplinkoje kasmet didėja. Medžiaga surinkta Saimos ežero pakrantėse, šalia urbanizacijos centų (Anttola, Astuvansalmi, Ristina, Imatra, Savonlinna, Orijärni, Mikkeli, Puumala) 2004 m. rudenį (spalio, lapkričio mėn.,) ir 2005 m. vasarą (birželio mėn.). Duomenys analizuoti naudojant Eric D. van Hullebusch 2004 m metodika – modifikuota A. Tessier metodika. Sunkiųjų metalų kiekiai nustatyti AAS ir voltimetru. Nustatyta, kad sunkieji metalai skirtinguose substratuose kaupiasi nevienodai, o didžiausias užterštumas jais teritorijose šalia trašų ir plieno fabrikų (Orijarni, Ristina) bei medžio apdirbimo įmonių (Anttola, Mikkeli). / Our living environment – the living nature and inanimate nature are extremely fragile and vulnerable. Among the various chemical pollutants the most prevalent are heavy metals. They are defined as the ones with permanent and various toxic effects, which endangers living nature and human health the most. The migration of this pollutant in the atmosphere is increasing every year. The samples were taken from the Saimaa lakeside near urban centres (Anttola, Astuvansalmi, Ristina, Imatra, Savonlinna, Orijärni, Mikkeli, Puumala ) in autumn 2004 (October, November) and summer 2005 (June). The materials were analyzed by using Eric D. van Hullebusch 2004 method – modified by A. Tessier methods. The quantity of heavy metals was measured by using a voltmeter and AAS. It was diagnosed that heavy metals are accumulating unevenly in the various substratum. And the biggest impurities were found in the territory around manufacturing of the chemical fertilizers and steel factories (Orijarni, Ristina), also wood processing factories(Anttola, Mikkeli).

The present review sought to clarify and synthesise the existing research of the role parental harshness and parental warmth have on children and adolescents with callous unemotional traits by comparing research across different study designs and study samples in a systematic review. The systematic review search rendered in 16 publications which revealed that callous unemotional traits moderate the relationship between parental harshness as well as parental warmth and behaviour problems in children and adolescents. The moderation effect was directed by the level of callous unemotional trait in the child or adolescent where those with low levels exhibited the most negative effects when exposed to parental harshness. Conversely, children or adolescents with elevated levels exhibited the most positive effects when being exposed to parental warmth. Furthermore, the review revealed that both forms of parenting predict changes in callous unemotional traits over time, where parental harshness increased traits and parental warmth decreased traits. These results are further discussed in relation to the contextual theories of Lykken’s parental competence and socialisation model as well as Kochanska’s conceptual model of conscience development.

Triazenido ions are isoelectronic to amidinato anions,[R'N C(R)=NR']- and have a broad versatility in coordination chemistry. Metal complexes including triazenido ligands find applications in various areas of chemistry. Triazenes and complexes including triazole derivatives show extensive applicability as for example in supramolecular chemistry and pharmacological compounds. This work presents deals with the study of new triazene derivatives with triazole substituents resulting from the click reactions, acting as ligands in complexes with Cu(I), Cu(II) and Au(I). The following ligands 1,3-bis(2-azidophenyl)triazene (2), 1-(methyl)-3-(2-(4-phenyl-1,2,3-triazole)triazene-N-oxide (4), 1-(phenyl)-3-(2-(4-phenyl-1,2,3-triazole)triazene (5), 1,3-bis(2-(4-phenyl-1,2,3-triazole)triazene (6) and, complexes 1,3-bis(2-azidophenyl)triazenide-κN11- triphenylphosphine-gold(I) (2a), bis-{1-(methyl)-3-[2-(4-phenyl-1,2,3-triazole-κN2)]triazenide-1-oxide-κ2N3,O}copper(II) (4b), 1-(phenyl)-3-(2-(4-phenyl-1,2,3-triazole)triazenide-κN- triphenylphosphine-κP-gold(I) (5a), 1,3-bis(2-(4-phenyl-1,2,3-triazole)triazenide-κN- triphenylphosphine-κP-gold(I) (6a), bis[1,3-bis(2-(4-phenyl-1,2,3-triazole-κN2)-μ-N3-triazenide]-κN11,κN13 copper(I)κN13,κN11´copper(I) (Cu Cu) (6b) were investigated. The compounds were characterized by IR, UV-Vis and NMR (1H e 13C) spectroscopy, low or high resolution mass spectrometry (EI, ESI, ESI(+)-TOF and ESI(-)-TOF) and X-ray diffraction on single crystal. Triazene (2) and complex (2a) exhibit intramolecular assembling through classical and non-classical hydrogen bonding. Complexes with Au(I), (2a), (5a) e (6a), the metal atom show linear coordination geometry. The metal atom in complex (6b) shows a T distorted coordination geometry, which is extended to a quadratic coordination resulting from d10 d10 interactions between Cu(I) ions. Triazene (6) and its respective complexes (6a) e (6b) exhibit intermolecular interactions of the type C−H···M. Antibacterial activity of triazene (5) and complex (5a) were assayed resulting to be inactive against the bacteria tested. / Os compostos triazenidos são isoeletrônicos a íons amidinatos [R'NH C(R)=NR'], e têm sido usados com sucesso na química de coordenação. A complexação a íons metálicos possibilita a sua aplicação em diversas áreas da química. Assim como os triazenos, os triazóis possuem vasta aplicabilidade, desde a química supramolecular até a área farmacológica. Este trabalho apresenta o estudo inédito de pré-ligantes triazenos contendo substituintes triazóis os quais foram obtidos a partir de reações de Click, e seus respectivos complexos de Cu(I), Cu(II) e Au(I). Foram sintetizados os pré-ligantes 1,3-bis(2-azidofenil)triazeno (2), 1-(metil)-3-(2-(4-fenil-1,2,3-triazol)triazeno-N-óxido (4), 1-(fenil)-3-(2-(4-fenil-1,2,3-triazol)triazeno (5), 1,3-bis(2-(4-fenil-1,2,3-triazol)triazeno (6) e os complexos 1,3-bis(2-azidofenil)triazenido-κN11-trifenilfosfina-ouro(I) (2a), bis-{1-(metil)-3-[2-(4-fenil-1,2,3-triazol-κN2)]triazenido-1-óxido-κ2N3,O}cobre(II) (4b), 1-(fenil)-3-(2-(4-fenil-1,2,3-triazol)triazenido-κN-trifenilfosfina-κP-ouro(I) (5a), 1,3-bis(2-(4-fenil-1,2,3-triazol)triazenido-κN-trifenilfosfina-κP-ouro(I) (6a), bis[1,3-bis(2-(4-fenil-1,2,3-triazol-κN2)-μ-N3-triazenido]-κN11,κN13 - cobre(I)κN13,κN11´cobre(I) (Cu Cu) (6b). Estes foram caracterizados por espectroscopia de IV, UV-Vis e RMN (1H e 13C), espectrometria de massas de baixa ou alta resolução (EI, ESI, ESI(+)-TOF e ESI(-)-TOF) e difração de raios X em monocristal. O triazeno (2) e complexo (2a) apresentam ligações de hidrogênio intermoleculares e intramoleculares do tipo clássica e não-clássica. Os complexos de Au(I), (2a), (5a) e (6a) possuem geometria de coordenação linear. O complexo (6b) apresenta uma geometria T distorcida, a qual é estendida para quadrática pela interação d10 d10 entre os átomos de Cu(I), o triazeno (6) e seus complexos (6a) e (6b) apresentam ainda ligações intermoleculares do tipo C−H···M. Foi testada a atividade antibacteriana do triazeno (5) e o complexo (5a), os quais mostraram-se inativos frente às bactérias testadas.

Les mécanismes de formation de phases dans des films minces du système ternaire Al-Cu-Fe et des systèmes binaires Al-Cu, Al-Fe et Cu-Fe ont été étudiés. Dans chacun des systèmes, plusieurs échantillons avec des compositions distinctes ont été préparés par pulvérisation cathodique. Des couches d’aluminium, de cuivre et de fer ont été déposées séquentiellement sur des substrats de silicium oxydé et ont été traités thermiquement par différentes méthodes puis caractérisés. Des mesures de diffraction de rayons X et de résistivité in-situ ont été effectuées pour suivre la formation des phases. Des recuits thermiques suivis de trempe ont été réalisés et les échantillons ont été caractérisés par diffraction des rayons X. L’analyse enthalpique différentielle a également été utilisée ainsi que des mesures simultanées in-situ de résistivité et de diffraction des rayons X. L’ensemble des résultats obtenus nous a permis de proposer des mécanismes de formation de phases pour chacun des échantillons étudiés et en utilisant des modèles théoriques de croissance de phases nous avons pu déterminer des données cinétiques sur la formation de phases dans ces films. / The mechanisms of phase formation in thin films have been studied in the Al-Cu, Al-Fe, Fe-Cu and Al-Cu-Fe systems. Several samples with different compositions have been prepared by sputtering. Aluminium, copper and iron layers were deposited onto oxidized silicon substrates, they were heat treated and characterized by using several techniques. In situ X-ray diffraction and resistivity measurements were used to follow the phase formation. Thermal annealings followed by quenching have also been carried out to get additional information.Differential Scanning Calorimetry and coupled in-situ resistivity and X-ray diffractionmeasurements were performed. The whole results allowed us to suggest a mechanism of phase formation for each sample and by using theoretical models of growth we determined kinetic data on the phase formation.

The purpose of this research was to generate the knowledge for formulating low-Cu and Cu-free brake friction materials without using and releasing hazardous materials that are listed on Washington State and California State Senate Bills. Model brake material samples were manufactured and tested in the Friction Assessment and Screening Test (FAST) and the full scale automotive brake dynamometer (Dyno) using a SAE J2430 test procedure. The SAE recommended a J2430 test procedure which provided the necessary data for the Brake Effectiveness Evaluation Procedure (BEEP) by the Brake Manufacturers' Council. The newly developed low-Cu and Cu-free brake friction materials were formulated by modifying a typical Non Asbestos Organic (NAO) (T-Baseline) formulation and a typical Semi-Metallic (M-Baseline) formulation. The NAO Cu-free brake friction materials contain geopolymer and natural hemp fibers as a partial replacement of phenolic resin and synthetic Kevlar fibers, respectively. Friction performance and wear data from a series of FAST tests were used to train an artificial neural network, which was used to optimize the NAO Cu-free formulations. Then, the optimized low-Cu and Cu-free brake friction materials were tested on the Dyno. Dyno test results showed that all NAO Cu-free brake friction materials have passed the Brake Effectiveness Evaluation Procedure (BEEP), did not exhibit thermal fade when temperature was increased and were slightly sensitive to speed. The NAO Cu-free brake friction materials exhibits slightly lower average friction level when compared to the baseline materials (T-Baseline). The Cu-free brake friction materials, as well as the rotors, exhibit higher wear than the detected wear on the T-Baseline material. The semi-metallic low-Cu and Cu-free brake friction materials have also passed the BEEP. Dyno test results indicated that the semi-metallic low-Cu and Cu-free friction materials did not exhibit thermal fade and were slightly sensitive to speed. The semi-metallic low-Cu and Cu-free materials exhibited lower friction level and higher wear on the pads when compared to the M-Baseline material. The semi-metallic Cu-free material outperformed the M-Baseline material in term of rotor wear. Analyses using scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) microanalysis on the tested materials show that the friction surface of the T-baseline material was covered with fully developed and stable friction layer (third body) consisting mostly of Fe-oxides, different forms of carbon and compounds of materials originally present in the bulk material. The NAO Cu-free materials (T30-15 and T30-16) did not develop a sufficient friction layer. The friction layer seemed to be responsible for the detected lower wear in the T-Baseline compared to the NAO Cu-free materials (T30-15 and T30-16), and it acted as a solid lubricant on the interface between the rubbing pad and the cast iron rotor lowering the adhesive forces. The friction and wear of the T-Baseline material was controlled by adhesive mechanisms. The NAO Cu-free materials (T30-15 and T30-16) with content of geopolymer replacing phenolic resin matrix exhibited extensive abrasive wear in addition to adhesive mechanisms. The capacity to form a friction layer on the surface plays a considerable role when lowering the wear of NAO brake friction materials. The friction layer was formed by compaction and interaction of brake wear particles, and its stability and character depend on the chemistry of the bulk materials in contact as well as the temperature, pressure and sliding speed during a friction process. SEM and EDX analyses also showed that the semi-metallic pads have developed friction layer on the friction surfaces. The difference was that the M-Baseline material had well developed friction layer, but the Low-Cu (M4) and Cu-free (M5) materials, had many smaller patches of friction layer disturbed on the surfaces.

Submitted by Luiz Felipe Barbosa (luiz.fbabreu2@ufpe.br) on 2015-04-17T14:27:33Z No. of bitstreams: 2 TESE Flávia Lucena.pdf: 1461854 bytes, checksum: c95dfad3364a7959e3f68649485b4dfb (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-04-17T14:27:33Z (GMT). No. of bitstreams: 2 TESE Flávia Lucena.pdf: 1461854 bytes, checksum: c95dfad3364a7959e3f68649485b4dfb (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013 / Relatos na literatura vêm utilizando nanoparticulas com o objetivo de carrear drogas e diminuir seus efeitos colaterais. Dentro dessa perspectiva estão às redes coordenadas a metais orgânicos ou MOFs. Este trabalho teve como objetivo realizar a incorporação de um fármaco antitumoral em uma rede de coordenação, visando melhorar sua biodisponibilidade para o organismo, bem como avaliar a toxicidade deste sistema in vitro e in vivo. Para isso foi realizado estudo teórico-computacional que nos permitiu a escolher o melhor fármaco a ser utilizado (5-fluorouracil) e a melhor rede de coordenação (Cu-BTC MOF), levando em consideração os tamanhos das moléculas dos mesmos em relação ao tamanho dos poros das MOFs Cu-BTC e MIL-53(Al). Os resultados das caracterizações químicas realizadas (UV-VIS, IV, CNHS, DRX, TGA/DTG e DSC) indicaram uma incorporação de 0,82 g de 5-fluorouracil para cada 1 g de MOF Cu-BTC após sete dias de agitação. A cultura celular in vitro demonstrou que o sistema 5-FU + Cu-BTC MOF apresentou atividade citotóxica significante quando comparado ao fármaco em solução. O teste de verificação do mecanismo de morte celular utilizando a citometria de fluxo indicou ser a apoptose o mecanismo de ação responsável para eliminação das células tumorais. O estudo de dissolução indicou uma liberação lenta e controlada de 39% do fármaco nos primeiros 30 minutos seguida da liberação de 82% do fármaco em 48 horas. Alterações histológicas só foram evidenciadas quando utilizada a dose de 750mg/kg sendo esta, a dose letal (DL50) encontrada. O teste da peritonite, verificação dos níveis de citocinas pro-inflamatórias e produção de óxido demonstraram que o sistema 5-FU + Cu-BTC MOF reduziu o número de leucócitos, os níveis de citocinas pró-inflamatórias e óxido nítrico, indicando que o sistema apresentou também atividade antiinflamatória para os testes realizados. Os resultados indicaram ser o sistema 5-FU+Cu-BTC MOF um excelente carreador de fármaco, com indicação de atividade anti-inflamatória, excelente atividade citotóxica via mecanismo de apoptose e liberação lenta e gradual do fármaco, o que possibilitou a diminuição na toxicidade do mesmo acompanhado de uma significante melhora terapêutica.

Submitted by Israel Vieira Neto (israel.vieiraneto@ufpe.br) on 2015-03-04T16:38:17Z No. of bitstreams: 2 DISSERTAÇÃO Emerson Marcello Ferreira Anastácio.pdf: 10089049 bytes, checksum: 0eb60791ae3e8e6cb281ce1df85c67e2 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-04T16:38:17Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Emerson Marcello Ferreira Anastácio.pdf: 10089049 bytes, checksum: 0eb60791ae3e8e6cb281ce1df85c67e2 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013-07-18 / A área investigada situa-se entre Fagundes e Itatuba (PB), geologicamente inserida no Terreno Alto Moxotó (TAM), Subprovíncia Transversal (DZT), Província Borborema, Nordeste do Brasil. Localmente ocorre um conjunto de corpos tabulares, lenticulares e sub-elípticos, de uma suíte de rochas graníticas e metamáfico-ultramáficas com lentes de rochas metacarbonáticas associadas, além de skarns, encaixados em um embasamento gnáissico-migmatítico (Complexo Floresta). Lentes de rochas metamáficas-ultramáficas, pertencentes a uma série basalto-toleiítica com afinidades de MORB, hospedam importantes ocorrências de Fe-Ti. Os skarns abrigam uma associação de quartzo-epidoto-sulfetos (Fe-Cu), disposta em estruturas do tipo brechada e stockwork, formadas por hidrotermalismo tardio que pode ter gerado mineralizações com potencial interessante, (e.g. Fe, Cu, Au), como já constatado em outros skarns da Província Borborema. Visando elucidar de modo mais realístico o modelo genético da mineralização estudada, no contexto temporal do hidrotermalismo, foi realizado o estudo geocronológico da principal ocorrência de skarns mineralizados em Fe-Cu, utilizando-se o par isotópico Re-Os em calcopirita (sulfeto dominante na paragênese do minério estudado). Embora o erro nas análises das razões isotópicas entre Re e Os ter sido aceitável (< 1 %), as amostras de calcopirita analisadas registraram concentrações extremamente baixas de Re (7 a 20 ppb) e Os (6 a 98 ppb), que ocasionaram uma tendência não-linear no diagrama concórdia, não permitindo um cálculo preciso da idade. Assim, após várias tentativas de geração de idades interpretáveis diante do contexto geológico local, este cálculo foi feito individualmente para as quatro frações analisadas, sendo que as que forneceram dados plausíveis no contexto geológico da área retornaram idades entre 0,52 Ga (amostra YK-566-1) e 2,05 Ga (YK-566-4). Enquanto a idade obtida pela amostra YK-566-1 pode representar o momento da precipitação dos sulfetos na área, associado ao hidrotermalismo tardio, durante o Estágio 3 Cambriano (~520 Ma), a amostra YK-566-4 (2,05 Ga) provavelmente possui informações isotópicas herdadas do episódio juvenil mais antigo relatado até o momento (2308 ± 22,5 Ma) ou de seu metamorfismo posterior em 2,012 Ga. Embora os métodos utilizados não tenham permitido considerações e conclusões mais consistentes, face ao contexto geológico da área estudada como conhecido até o momento, os dados de Carmona (2006) combinados com os de Santos et al. (2013a), bem como os gerados neste trabalho, permitem, de fato, traçar uma evolução aceitável, onde a granitogênese neoproterozoica provavelmente seria a responsável pelo hidrotermalismo da área (~547 Ma), embora a mineralização primária de Fe-Cu provavelmente seja orosiniana (2,050-1,800 Ga).

Le développement de cancer entraîne une dérégulation du métabolisme du cuivre (Cu) qui a notamment été étudiée par analyse de la composition isotopique naturelle du Cu. Les cellules tumorales hépatiques sont enrichies en isotopes lourds du Cu par rapport aux cellules péri-tumorales. Le but de cette thèse est d'identifier les mécanismes responsables de cette différence, en utilisant la levure Saccharomyces cerevisiae dont les mécanismes de réduction et d'import du Cu sont proches de ceux de l'Homme. En mutant les gènes codants pour les importateurs ou les réductases du Cu, j’ai montré que son import protéique génère un enrichissement intracellulaire en isotopes légers du Cu, qui est modulé par l'activité des réductases. Une modélisation numérique m’a permis de montrer que le flux de Cu par les importateurs haute-affinité Ctr est linéairement et négativement corrélé à la composition isotopique du Cu. Ce flux étant modulé par la capacité de réduction membranaire du Cu, j’ai pu lier l'enrichissement en isotopes lourds du Cu des cellules hépatiques tumorales à une diminution de l'activité des réductases membranaires. Par ailleurs, pour un même fond génétique, j'ai mis en évidence une corrélation entre un moindre enrichissement en isotopes légers du Cu et une résistance accrue à un médicament anticancéreux, le cisplatine. De plus, le traitement au cisplatine entraîne un enrichissement des cellules en isotopes lourds du Cu d'autant plus petit que la souche est résistante au cisplatine. Ainsi, ces résultats montrent que la mesure de la composition isotopique du Cu avant et après traitement au cisplatine pourrait permettre de suivre l'apparition d’une chimiorésistance chez les malades, caractérisée par un enrichissement en isotopes lourds du Cu dans les tumeurs, ce qui ouvre la voie au développement d'un nouveau biomarqueur non-invasif de l'apparition d'une résistance au cisplatine. / Cancer development leads to Cu metabolism disregulation which were especially studied by the natural copper (Cu) isotopic composition. Hepatocellular carcinoma (hCC) are enriched in heavy Cu isotopes compared to peri-tumoral cells. The goal of this thesis is to identify the mechanism responsible for this difference. I used the yeast Saccharomyces cerevisiae where Cu reduction and Cu import mechanism are close to the human. By mutating the genes coding for Cu reductases or Cu importers, I showed that protein Cu import generate an intracellular light Cu enrichment which is modulated by Cu reductases activity. With a numerical modelisation I calculated that the Cu flux through high-affinity Cu importers is linearly and negatively correlated to the natural Cu isotopic composition. This flux is modulated by the cell reduction ability. Therefore, I have linked the heavy Cu isotopes enrichment in hCC to a lower reductases activity. Besides, for a same genetic background, I observed a correlation between a lower light Cu enrichment and an higher resistance to a anti-tumoral drug, the cisplatin. Moreover, I observed that cisplatin treatment leads to an enrichment in heavy Cu isotopes which is lower for resistant to cisplatin strains. Those results shown that the Cu isotopes measurement in tumors before and after the cisplatin treatment might be used to trace the chemoresistance apparition in patient with cancer which is characaterize by a tumoral heavy Cu isotopes enrichment. This results might pave the way to the development of a new prognosis biomarker of the cisplatin resistance apparition.

The recognition of the negative impact of NOx resulted in increasingly tighter automotive emission regulations. Companies are under pressure to develop methods, which can meet the legislative demands. After treatment solutions, and especially Selective Catalytic Reduction, became the focus of research and have shown so far promising results. However, more in depth understanding of the SCR process under different conditions is needed. This thesis describes an investigation of the SCR performance using gas and urea injections under steady state and transient conditions undertaken on a light duty diesel engine using a 1D exhaust system designed for uniform flow across the catalyst. Under steady state conditions, the SCR performance was examined for low and high temperature conditions. Ammonia was supplied either as 5% ammonia gas or in form of urea injection. The engine was operating at 1500 rpm and 6 and 8 bar BMEP to provide an exhaust gas temperature of 210 °C and 265 °C respectively. Also, the effect of SCR brick length on the NOx conversion was investigated using SCR catalysts of length 30, 45 and 75 mm. To measure the influence of NO2:NOx ratio on the SCR performance, different sizes of standard DOC were used. NH3:NOx dosage levels included; α~0.5 - deficient ammonia, α~1.0 - stoichiometric ammonia, α~1.25 - excess ammonia. Gas emissions were measured before and after the SCR catalysts with a Horiba FTIR analyser during steady state and long transient tests. It was found that conditions such as temperature and NO2:NOx had the biggest impact on the SCR performance. During the steady state engine conditions, at α~1.0 ammonia dosing and NO2:NOx ratio of 0, only 17% of NO was converted in the first 30 mm of the SCR brick length. The conversion was improved at high temperature (263 °C) to 31%. A fast response CLD analyser was used during short transient testing to sample emissions with a high resolution. The short transient test with standard 0.5 and 1 DOC, and fixed ammonia dosing, showed that NOx conversion was reduced during the ramp event due to deficient ammonia and a drop in the supplied NO2:NOx ratio. During urea injection experiments, urea was injected either through an oblique pipe arrangement with a mixer device placed downstream or directly into a mixing can. In this case the mixer device was replaced with a straight pipe. A 75mm SCR was fitted and to ensure that supplied NO2:NOx ratio was zero, a palladium only DOC was used post a DPF. It was found that a large proportion of urea decomposition and hydrolysis was occurring on the surface of the SCR catalyst. Comparing NOx performance between urea injection and ammonia gas dosing experiment, more NO was converted for a given NH3:NOx ratio when ammonia was supplied in the form of gas. That was true for low and high temperature tests. For most studies, a long 10 degree diffuser was used in front of the SCR to provide uniform gas distribution across the catalyst. In addition SCR performance was investigated with a 180 degree sudden expansion diffuser in order to measure the influence of temperature and velocity profiles. During this study, a 45 mm SCR catalyst was used to provide a moderate amount of NO conversion and ammonia slip. The results showed that the flow and temperature distribution upstream of the SCR catalyst will have an effect on the NOx conversion, and that gas velocity has bigger impact on NOx conversion than gas temperature.