Use of welded titanium alloy to aluminium alloy structures in the aerospace industry has a number of potential benefits for both cost and weight saving by enabling titanium to be used only in the most critical parts, with the cheaper and lighter aluminum alloy making up the rest of the structure. However, due to the formation of brittle intermetallic compounds (IMC) at interface and the enormous gap in melting point, the welding of titanium to aluminium remains a major challenge. Solid state welding processes are most likely to be successful since they do not involve any melting, and so issues associated with the large difference in melting point and the high reaction rate of the liquid phase are avoided. In this study, an emerging low energy input solid state welding process - high-power ultrasonic spot welding (USW) was applied to weld Al and Ti (AA6111-T4/Ti6Al4V and AA2139-T8/Ti6Al4V combinations). No obvious intermetallic reaction layer was observed on the Al/Ti interface even using transmission electron microscopy. As a result, the maximum joint strength measured reached the same level as similar Al-Al (AA6111) welds and greatly exceeded those observed in Al-Fe and Al-Mg joints made using the same technique, in which a brittle reaction layer forms rapidly. However, the Al/Ti welds always failed at the weld interface after natural ageing, which is not desirable due to the low fracture energy associated with interfacial fracture mode. By using high resolution STEM-EDS, residual oxides and Si segregation were detected on the as-welded Al/Ti interface, which are thought to be factors that result in the no reaction layer Al/Ti interface. The Si segregation is predicted to be able to increase the weld interface cohesion through thermodynamic calculation. A series of prolonged heat treatment experiments were performed to understand the Al-Ti reaction layer growth kinetics and to explain the lack of reaction layer in as-welded Al-Ti joint. Al3Ti (D022 structure) was the only Al-Ti intermetallic phase observed in the reaction layer (IMC layer). In pure Al/Ti joints, it is found that the very long slow-growth stage of IMC layer is probably caused by the residual oxides on the interface. Calculations show that grain boundary (GB) diffusion makes the major contribution to the effective diffusion coefficient in the Al3Ti layer. In AA2139/Ti joints, the IMC layer growth is significantly slower than that in pure Al/Ti joints. The effects of alloying elements on the IMC layer growth was studied in detail. Cu was observed to segregate on both the Al3Ti grain boundaries and the Al3Ti/Ti interface. Si also segregated on the the Al3Ti/Ti interface and enriched in the Al3Ti layer. Both Cu and Si are thought to retard IMC layer growth. Interestingly small patches of Al were found trapped in the IMC layer; its formation mechanism is discussed. In pure Al/Ti6Al4V joints, the IMC layer growth rate did not change significantly. The presence of V greatly retarded the Al3Ti grain growth at high annealing temperature (630 °C) and suppressed the anisotropic growth of Al3Ti at 600 °C. Overall this study successfully joined Al/Ti by USW and systematically investigated the grain size effect and alloying effects on the Al3Ti layer growth. The present study for the first time: (a) observed the no-IMC-layer Al/Ti weld interface; (b) observed Cu segeration on Al3Ti GBs; (c) quantitatively studied the grain size effect on Al3Ti layer growth kinetics; (d) observed the orientation relationship between trapped Al islands and the adjacent Al3Ti grains; (e) observed that V greatly retarded the anisotropic growth of Al3Ti grains.

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Les procédés de fabrication de produits carnés stables à température ambiante s'articulent autour de la théorie des barrières et du couplage d'opérations unitaires telles que le salage, le séchage, la fermentation, le fumage. Dans les pays du Nord, ces procédés traditionnels ou industrialisés, aboutissent à des produits finis à la fois stables à température ambiante et prêts-à-consommer. Pour contrecarrer l'altération de la viande, accrue en conditions tropicales ou en conditions d'hygiène non maîtrisées, les procédés traditionnels du Sud mettent en œuvre des traitements plus drastiques et aboutissent à des produits nécessitant une préparation ultérieure pour être consommés (cuisson, dessalage).L'objectif général de ce travail est de proposer un procédé innovant adapté aux pays du Sud aboutissant à un produit carné salé/séché/fermenté stable à température ambiante et prêt-à-consommer. L'innovation consiste à traiter des morceaux de viande en couplant une pré-stabilisation par Déshydratation-Imprégnation par Immersion (DII) à une étape maîtrisée de fermentation de surface. Par une stratégie expérimentale progressive associée à la modélisation, cette thèse étudie le couplage DII/fermentation de surface et détermine quels leviers sont à disposition pour optimiser ce couplage. Les réponses apportées s'appuient sur trois parties. Une première étude sur aliment réel a validé le couplage de la DII avec une fermentation de surface par Lactobacillus sakei. Dans un deuxième temps, une étude en milieu modèle a mis en évidence l'influence des facteurs environnementaux d'intérêt (activité en eau, teneur en sel, pH et teneur en acide lactique) sur la croissance en surface de L. sakei. Enfin, un modèle global a été construit pour analyser le couplage entre les transferts de matière (eau, sel, sucres et acide) entre la surface et le cœur de l'aliment, et le métabolisme fermentaire à la surface du produit.Mots-clés : produits carnés, Déshydratation-Imprégnation par Immersion, fermentation de surface, Lactobacillus sakei, cinétiques de croissance, transferts de matière. / The fabrication of shelf-stable cured meat products is based on the hurdle technology and on the coupling of unit-operations such as salting, drying, fermentation and smoking. In Northern countries, these processes whether traditional or industrialized, lead to end-products which are both shelf-stable and ready-to-eat. Meat spoilage is accelerated in tropical conditions or when the general hygiene is not controlled. In order to counteract it, traditional processes in these conditions use more drastic treatments leading to end-products which require an additional preparation step before being consumed (cooking, desalting).The general objective of this work is to propose an innovative process adapted to Southern countries and leading to a salted/dried/fermented meat product which is shelf-stable and ready-to-eat. The innovation consists in treating meat pieces by coupling a pre-stabilization by Dehydration-Impregnation by Soaking (DIS) with a controlled surface fermentation step. By means of a progressive experimental strategy associated with modelization, this thesis studies the DIS/surface fermentation coupling and determines which levers are available to optimize it.The answers comprised three parts. Firstly, a study on the real food product validated the coupling of DIS with a surface fermentation by Lactobacillus sakei. Secondly, a study on a model device showed the influence of relevant environmental factors (water activity, salt content, pH and lactic acid content) on the surface growth of L. sakei. Finally, a global model was built to analyze the coupling of mass transfers (water, salt, sugars, acid) between the surface and the core of the product, and the fermentative metabolism at the surface of the product.Keywords: meat products, Dehydration-Impregnation by Soaking, surface fermentation, , Lactobacillus sakei, growth kinetics, mass transfers.

A produção de biofármacos segue um crescente interesse industrial e social. Atualmente existem vários tipos de tratamento contra o câncer, porém, a maioria desses tratamentos não atua unicamente no alvo terapêutico. Um estudo realizado por pesquisadores do Instituto Butantan identificou uma proteína com ação anticoagulante e antitumoral, codificada por um gene proveniente das glândulas salivares do carrapato Amblyoma cajennense . Esse gene foi inserido em um plasmídeo e expresso com sucesso na bactéria Escherichia coli BL21DE3. Estudos pré-clínicos mostraram que a injeção in vivo de Amblyomin-X reduziu a formação de massa tumoral induzida por células de melanoma B16F10 em camundongos. Este trabalho contempla o estudo das condições de cultivo para obtenção da proteína Amblyomin-X com a linhagem Escherichia coli BL21DE3 recombinante em biorreatores. Para se determinar a melhor condição de biossíntese da proteína recombinante Amblyomin-X estabeleceu-se uma estratégia de cultivo para a etapa de crescimento do microrganismo e estudaram-se três diferentes fatores na etapa posterior à do crescimento microbiano, ou seja, na etapa de biossíntese da proteína: i) a concentração do indutor IPTG (Isopropil β-D-1-tiogalactopiranosídeo) no momento de indução da proteína; ii) a temperatura de cultivo durante a etapa de biossíntese da proteína; e iii) a concentração celular no início da etapa de biossíntese da proteína. Para a realização dos ensaios foi proposto um planejamento experimental delineamento composto central rotacional (DCCR) escolhido para os três fatores em estudo e resultou na condução de 17 ensaios. Os ensaios foram realizados com a estratégia de condução proposta, mantendo o valor de &#956x entre 0,20 e 0,23 h-1 na etapa de batelada alimentada, o que possibilitou atingir a concentração celular desejada com a formação de ácido acético em concentrações não inibitórias. Como resultado do planejamento experimental, a obtenção dos valores ótimos dos fatores para a etapa de produção da proteína: temperatura de 38 °C, concentração celular de 35,27 g/L e concentração do indutor IPTG de 0,10 mM resultou em um protocolo de processo que obteve 8,07 g/L de proteína recombinante, valor máximo obtido e validado. / The production of biopharmaceuticals follows an increasing industrial and social interest. Currently there are several types of cancer treatment, however, most of these treatments do not only act on the therapeutic target. A study by researchers at the Butantan Institute identified a protein with anticoagulant and antitumor action, encoded by a gene from the salivary glands of the Amblyoma cajennense tick. This gene was inserted into a plasmid and successfully expressed on the bacterium Escherichia coli BL21DE3. Preclinical studies have shown that the in vivo injection of Amblyomin-X reduced the tumor mass formation induced by B16F10 melanoma cells in mice. This work includes the study of the culture conditions to obtain Amblyomin-X protein with the recombinant Escherichia coli strain BL21DE3 in bioreactors. In order to determine the best biosynthesis condition of the recombinant Amblyomin-X protein, a culture strategy was established for the growth stage of the microorganism and three different factors were studied in the post-microbial growth stage, that is, in the biosynthesis stage of the protein: i) the concentration of the IPTG (Isopropyl β-D-1-thiogalactopyranoside) inducer at the time of induction of the protein; ii) the culture temperature during the protein biosynthesis step; and iii) the cell concentration at the beginning of the protein biosynthesis step. For the accomplishment of the tests it was proposed an experimental design - central rotational compound design (DCCR) - chosen for the three factors under study and resulted in the conduction of 17 tests. The tests were performed with the proposed conduction strategy, maintaining the value of µ &x between 0.20 and 0.23 h-1 in the fed batch stage, which allowed to reach the desired cellular concentration with the formation of acetic acid in non-inhibitory concentrations. As a result of the experimental design, obtaining the optimum values of the factors for the protein production step: temperature of 38 °C, cell concentration of 35.27 g/L and concentration of the IPTG inductor of 0.10 mM resulted in a process protocol which obtained 8.07 g / L of recombinant protein, maximum value obtained and validated.

Rokshana Parvin Molecular epidemiology and biological properties of avian influenza viruses of subtype H5N1 and H9N2 Institute of Virology Submitted in November 2014 Pages 106, Figures 7, Table 1, References 339, Publications 4 Keywords: Avian Influenza Virus, H5N1, H9N2, Reassortment, Mutation, Replication and Growth kinetics Introduction Avian influenza viruses (AIVs) are the major cause of significant disease outbreaks with high morbidity and mortality worldwide in domestic birds resulting in great economic losses. Especially the subtypes of highly pathogenic avian influenza viruses (HPAIV) H5N1 and low pathogenic avian influenza viruses (LPAIV) H9N2 became the most prevalent AIVs in poultry causing regular disease outbreaks in many countries of Asia, the Middle East and Europe and are still ongoing events. Therefore, continues monitoring, surveillance and characterization of the circulating viruses are of high priority. Objectives The current study was designed for three main objectives; i) Molecular epidemiology of the HPAIV H5N1 in migratory birds in Bangladesh, ii) Molecular characterization of the AIV subtype H9N2 and iii) Biological properties of the AIV subtype H9N2. Materials and methods In first the part of the investigations, two HPAIV H5N1 strains were confirmed from 205 pools of fecal surveillance samples in Bangladesh. The two isolated H5N1 viruses were characterized by genome amplification and sequence analysis of the all eight genome segments. In the second part of the investigations, a confirmed AIV H9N2 from a retrospective analysis derived from a poultry farm in Bangladesh was characterized. Furthermore, three AI-H9N2 viruses were isolated and characterized from a commercial broiler and broiler breeder flock with clinical respiratory manifestations in Egypt. Full length genome amplification, cloning, sequencing and comprehensive phylogenetic analyses were performed for all eight genome segments. In the final part of the study, four selected Eurasian lineage H9N2 viruses - three G1 sub-lineages H9N2 and one European wild bird H9N2 virus - were propagated in embryonated chicken eggs (ECE) and Madin-Darby canine kidney epithelial cell culture systems. The ECE-grown and cell culture-grown viruses were monitored for replication kinetics based on tissue culture infectious dose (TCID50), hemagglutination assay (HA) and quantitative real time RT-PCR (qRT-PCR). The cellular morphology after infections was analyzed by immunofluorescence assay and cellular ELISA was performed to screen the sensitivity of the viruses to amantadine. Results The two newly isolated HPAIV H5N1 strains from migratory birds belonged to clade 2.3.2.1 and clustered together with other recently isolated viruses in Bangladesh derived from ducks, chickens, quails and crow. The amino acid sequences were also genetically similar although, some unique amino acid substitutions were observed. These substitutions were not related to the known conserved region of the molecular determinants of the virus. The phylogenetic analyses of the isolated AIV H9N2 from Bangladesh and Egypt revealed their close relationship with their respective contemporary isolates and maintained ancestor relation with A/Quail/HK/G1/1997 confirming that all studied H9N2 belonged to G1 sub-lineage. All six internal gene segments of the Bangladeshi AIV H9N2 showed high sequence homology with the HPAIV subtype H7N3 from Pakistan. In addition, also the PB1 internal gene showed high nucleotide homologies with a recently circulating HPAI-H5N1 virus from Bangladesh. Thus, the Bangladeshi AIV H9N2 is genetically a unique strain which shares internal gene segments with different HPAI viruses and takes part in reassortment events. On the other hand, the internal gene segments of the Egyptian H9N2 viruses were similar to the other members of the G1 sub-lineage with no evidence of reassortment events. In this virus rather point mutations within their respective gene segments are observed. With regard to the biological characterization, the three G1-H9N2 viruses produced comparatively higher titer than the Eurasian wild type-AIV H9N2. Overall, the ECE-grown viruses yielded higher titers than cell culture-grown viruses. Following a single passage in cell culture, individual nucleotide substitutions were noticed in HA, NA and NS gene sequences but none of them are related to the conserved region that can alter virus pathogenesis or virulence. All of the studied H9N2 viruses were sensitive to amantadine. Conclusion The present study demonstrated for the first time the presence of HPAI H5N1 in the wild migratory bird population in Bangladesh and determine as one of the major cause to introduce the new clade of HPAIV H5N1 into the Bangladeshi poultry flocks. The Bangladeshi AIV H9N2 strain has exhibited two independent reassortment events with HPAIV of subtype H7N3 and H5N1.The Egyptian AIV H9N2 strains were limited to regular point mutations which is very common for AIVs. The G1-H9N2 viruses showed a higher replication profile when compared to European wild bird-AIV H9N2. Both the ECE and MDCK cell system allowed efficient replication but the ECE system is considered as the better cultivation system for H9N2 viruses in order to get maximum amounts of virus within a short time period. In this study new strains of AIV H9N2 and H5N1 with significant genetic constitutions were described. Thus, continuous monitoring of the field samples, rapid reporting soon after outbreaks, molecular characterization to confirm the emergence of new reassortant strains and the biological properties to know its impact on the virulence are recommended. / Rokshana Parvin Molekulare Epidemiologie und biologische Charakterisierung von aviären Influenzaviren der Subtypen H5N1 und H9N2 Institut für Virologie Eingereicht im November 2014 Seiten 106, Abbildungen 7, Tabelle 1, Literaturangaben 339 , Publikationen 4 Schlüsselwörter: Aviäres Influenza Virus, H5N1, H9N2, Reassortment, Mutation, Replikation und Wachstumskinetik Einleitung Weltweit kommt es in der Geflügelproduktion durch Infektionen mit aviären Influenzaviren (AIV) zu hohen Morbiditäts- und Mortalitätsraten und damit verbunden zu hohen wirtschaftlichen Verlusten. Zu den bedeutenden AIV in der Geflügelwirtschaft werden die hoch pathogenen aviären Influenzaviren (HPAIV) des Subtyps H5N1 sowie AIV des Subtyps H9N2 gezählt. Letztere besitzen die Charakteristika von niedrigpathogenen aviären Influenzaviren. Durch diese Subtypen kommt es regelmäßig in vielen Ländern in Asien, im Nahen Osten und Europa zu wiederholten Krankheitsgeschehen. Dies bedingt die dringende Notwendigkeit von andauerndem Monitoring, Überwachung und Charakterisierung der zirkulierenden Viren. Ziele der Untersuchungen Die vorliegende Studie soll folgende drei Hauptfragestellungen beantworten: i) Molekulare Epidemiologie des HPAIV H5N1 bei Zugvögeln in Bangladesch, ii) Molekulare Charakterisierung von AIV des Subtyps H9N2 und iii) Biologische Eigenschaften von AIV des Subtyps H9N2. Materialien und Methoden Der erste Teil der Arbeit befasst sich mit zwei HPAIV Stämmen des Subtyps H5N1, welche im Monitoring Programm in Bangladesch von insgesamt 205 gepolten Kotproben, isoliert wurden. Die Charakterisierung der beiden Isolate erfolgte durch Vervielfältigung der acht Genomsegmente und nachfolgende phylogenetische Analysen. Der zweite Teil der Arbeit beschreibt die retrospektive Analyse eines AIV des Subtyps H9N2, welches von einer Geflügelproduktionsanlage in Bangladesch eingesandt wurde. Weiterhin wurden aus einer Geflügelmast- und Legehennenhaltung mit respiratorischer Symptomatik drei AIV des Subtyps H9N2 isoliert und charakterisiert. Auch hier wurde das gesamte Genom amplifiziert, kloniert und nachfolgend phylogenetisch analysiert. Im letzten Teil der Studie wurden vier europäische AIV H9N2 Isolate, von welchen 3 Isolate zur H9N2 Sublinie G1 gehören und ein Isolat von einem Wildvogel selektiert und in embryonierten Hühnereiern (EHE) und auf Madin-Darby canine kidney (MDCK) Zellen passagiert. Mittels 50% tissue culture infectious dose (TCID50), Hämagglutinationstest (HA) und RT-real-time-PCR (qRT-PCR) wurden von diesen so passagierten Viren die Vermehrungskinetik bestimmt. Die Morphologie der infizierten Zellen nach Infektion wurde mittels Immunfluoreszenztest analysiert. Eine Bestimmung der Amantadin Empfindlichkeit dieser Viren erfolgte mit einem ELISA. Ergebnisse Die beiden neuen HPAIV des Subtyps H5N1 von Zugvögeln können in die Clade 2.3.2.1 eingeordnet werden und clustern mit kürzlich aus Enten, Hühnern, Wachteln und Krähen isolierten AIV aus Bangladesch. Eine Verwandtschaft der Viren konnte auch auf Ebene der Aminosäure Sequenz gezeigt werden, obwohl einige einzigartige Aminosäure Austausche nachgewiesen wurden. Diese Austausche zeigen keine Verbindung mit bekannten konservierten Regionen der molekularen Determinanten der Viren. Die phylogenetische Analyse der AIV aus Bangladesch und Ägypten zeigt eine deutliche Verbindung mit den derzeit zirkulierenden AIV auf diesem geographischen Gebiet sowie die Verwandtschaft zu dem Isolat A/Quail/HK/G1/1997. Dies bestätigt, dass die in dieser Studie analysierten AIV zu der Subline G1 gehören. Alle sechs internen Gensegmente des AIV H9N2 aus Bangladesch zeigen eine hohe Sequenz Homologie mit einem HPAIV des Subtyps H7N3 aus Pakistan. Zusätzlich zeigt das interne Gene PB1 eine hohe Homologie auf Nukleinsäureebene zu einem derzeit in Bangladesch zirkulierenden HPAIV des Subtyps H5N1. Somit ist das AIV H9N2 aus Bangladesch als ein einzigartiges Isolat anzusehen, welches durch Reassortierung interne Gensegmente mit hochpathogenen AIV teilt. Im Gegensatz dazu, sind die internen Gene des AIV H9N2 aus Ägypten sehr ähnlich zu anderen Mitgliedern der Sublinie G1, welche keine Hinweise auf Reassorierung zeigen. Nur einzelne Punktmutationen konnten in den entsprechenden Gensegmenten nachgewiesen werden. In Hinblick auf die biologische Charakterisierung, konnte in den drei AIV H9N2 der Sublinie G1 vergleichsweise höhere Titer nachgewiesen werden als in einem europäischen AIV H9N2 Wildtypisolat. Insgesamt zeigten die in EHE passagierten Viren höhere Titer als die MDCK-Zell passagierten Viren. Schon nach einer Passage auf Zellkultur konnten einzelne Nukleotidaustausche in den HA, NA und NS kodierenden Gensegmenten nachgewiesen werden, wobei keine dieser Veränderungen einen Einfluss auf konservierte Regionen haben, die die Pathogenese oder Virulenz der Viren beeinflussen. Alle untersuchten H9N2 Viren sind sensitiv gegenüber Amantadin. Schlussfolgerungen Die vorliegende Studie zeigt erstmalig das Vorkommen von HPAIV H5N1 bei Zugvögeln in Bangladesch, welches als Haupteintragsquelle der neuen HPAIV H5N1 in der dortigen Geflügelhaltung angesehen wird. Das AIV H9N2 aus Bangladesch zeigt zwei unabhängige Reassortierungen mit HPAIV des Subtyps H7N3 und H5N1. Hingegen zeigt das ägyptische AIV H9N2 Punktmutationen, welche sehr typisch für diese Viren sind. Die hier untersuchten AIV H9N2 der Sublinie G1 zeigen im Vergleich zu einem europäischen AIV H9N2 eine höhere Replikationsrate. Eine Replikation der Viren konnte in EHE und MDCK-Zellen gezeigt werden, jedoch wird das EHE als das geeignetere System für die Kultivierung von H9N2 Viren betrachtet, da hier in einer kürzeren Zeitspanne mehr Virus produziert werden kann. Des Weiteren konnten in dieser Studie neue Isolate von AIV des Subtyps H9N2 und H5N1mit einem bedeutenden genetischen Aufbau beschrieben werden. Daher wird ein kontinuierliches Monitoring von Feldproben, unverzügliche Meldung von Ausbruchsgeschehen, die molekulare Charakterisierung zur Dokumentation eventuell auftretender neuer Reassortanten sowie Untersuchungen der biologischer Eigenschaften zur Virulenzbestimmung empfohlen.

Proteins are important biological products with unique functions, annually produced at the hundreds of millions of dollars value on a worldwide basis. The application of crystallization for these materials primarily was led by structural biologists and crystallographers who are keen on obtaining large and well-ordered crystals for protein structure determination via X-ray diffraction. Usually for this, crystallization is done on a small scale by vapor diffusion using a supersaturated solution of the material. In the past decades, production crystallization has slowly received increasing attention for the large-scale recovery of proteins. Among the numerous products, an industrial enzyme (alpha-amylase) that is extensively involved in food processing and laundry products was chosen for examination due to the lack of relevant data in the literature and the potential industrial interest in crystallizing this material. The chosen alpha-amylase is a product of Genencor International (the Danisco division) and is derived from a genetically modified Bacillus licheniformis. In parallel to the underlying principles that govern the bulk crystallization of small molecules, the broad topics of investigation for this macromolecular material included determination of solubility, studies of nucleation thresholds, and investigation of crystal growth kinetics and special phenomena accompanying the crystallization process. All these studies were preceded by a series of characterization tests conducted for the material. On the whole, this study aimed to extend the existing fundamental knowledge of bulk crystallization for biological macromolecules. Specifically, it intended to enrich the solubility and crystallization kinetic data for the alpha-amylase. The experimental data of this study were all obtained at conditions in line with industrial practice, which included the use of moderate temperatures, mild pH conditions and simple inorganic salts ((NH4)2SO4, Na2SO4 and NaCl) in order for the findings to be transferred to the industry directly. In a 20 mM sodium phosphate buffer (with no added salts), alpha-amylase solubility increased with solvent temperature and had a minimum at pH between 6.4 and 7.1. A generalized equation (as a function of pH and temperature) was obtained to correlate the data. The three inorganic salts examined affected the alpha-amylase solubility in a different manner, both qualitatively and quantitatively. Evidently, the interaction effect of a salt varied with solution pH. This confirms the importance of studying solubility with the two or more condition parameters at the same time. With relevance to crystal growth, the metastable region of the material was relatively wide at (NH4)2SO4 and Na2SO4 concentrations corresponding to maximum solubility. For example, σSNT was 1.2  0.2 in solutions with 5 wt% ammonium sulfate at pH 7.0 and 25oC. A wide metastability range is useful for the practical operation of batch crystallizers as nucleation can be minimized. This range, however, diminished as the salt concentration increased beyond the maximum solubility points, imposing a limit on the range of salt concentration favorable for growth processes. In systems with no added salts at pH 7.0, the solution metastability was slightly higher at 10oC than at 40oC. This would suggest a future further examination of the salt system at a lower temperature, say of 10oC. To develop a batch crystallizer, the growth kinetic data of the material have to be known. Throughout the growth studies, the alpha-amylase crystals obtained were lozenge-shaped thin plates. Apparently, habit was not influenced by the crystallization conditions chosen. Similar to other proteins crystallized in bulk, the growth rate of alpha-amylase demonstrated a second-order dependence upon supersaturation. Importantly, the alpha-amylase demonstrated crystal growth rate dispersion (GRD) under all the conditions tested. To simplify the analysis of growth kinetic results, the seed crystals used were common history (CH) seeds whose growth rates are proportional to their sizes. The spread of growth rates (CV) was 0.54 for the unsieved CH seeds used. Due to GRD, growth rate coefficient data varied with crystal size. For instance, in solutions containing 5 wt% ammonium sulfate at pH 7.0 and 25oC, the growth rate coefficient for seed crystals initially at 20 m was 2.47 m/hr. This order of magnitude was equivalent to that of many other proteins. Although being small, industrial crystallization was feasible with these kinetics, as demonstrated by the sample design calculations included. To improve the design, it is recommended to further examine the solubility, metastability and growth kinetics of the above system at other temperatures to obtain a wider growth rate range. As the important phenomenon of growth rate dispersion has seldom been examined for protein and enzyme materials in the crystallization literature, this study is a significant contribution to this area.

Graphene is a two dimensional carbon material whose outstanding properties have been envisaged for a variety of applications. Cu-catalyzed chemical vapour deposition (Cu-CVD) is promising for large scale production of high quality monolayer graphene. But the existing Cu-CVD technology is not ready for industry-level production. It still needs to be improved on some aspects, three of which include synthesizing industrially useable graphene films under safe conditions, visualizing the domain boundaries of the continuous graphene, and understanding the kinetic features of the Cu-CVD process. This thesis presents the research aiming at these three objectives. By optimizing the Cu pre-treatments and the CVD process parameters, continuous graphene monolayers with the millimetre-scale domain sizes have been synthesized. The process safety has been ensured by delicately diluting the flammable gases. Through a novel optical microscope set up, the spatial distributions of the domains in the continuous Cu-CVD graphene films have been directly imaged and the domain boundaries visualised. This technique is non-destructive to the graphene and hence could help manage the domain boundaries of the large area graphene. By establishing the novel rate equations for graphene nucleation and growth, this study has revealed the essential kinetic characteristics of general Cu-CVD processes. For both the edge-attachment-controlled and the surface-diffusion-controlled growth, the rate equations for the time-evolutions of the domain size, the nucleation density, and the coverage are solved, interpreted, and used to explain various Cu-CVD experimental results. The continuous nucleation and inter-domain competitions prove to have non-trivial influences over the growth process. This work further examines the temperature-dependence of the graphene formation kinetics leading to a discovery of the internal correlations of the associated energy barriers. The complicated effects of temperature on the nucleation density are explored. The criteria for identifying the rate-limiting step is proposed. The model also elucidates the kinetics-dependent formation of the characteristic domain outlines. By accomplishing these three objectives, this research has brought the current Cu-CVD technology a large step forward towards practical implementation in the industry level and hence made high quality graphene closer to being commercially viable.

Comissão Nacional de Energia Nuclear / A corrosão causada por H2S biogênico frequentemente resulta em danos extensos na indústria do petróleo. O presente trabalho avaliou parâmetros de crescimento microbiano e aplicou metodologias de determinação de sulfetos por técnicas espectrofotométrica na região da luz visível e radiorespirométrica para avaliação da atividade metabólica, correlacionando com a população de bactérias redutoras de sulfato, determinada através da técnica do Número Mais Provável (NMP). Amostras de água de formação e consórcio de BRS foram avaliadas através do arraste de sulfetos estáveis produzidos biogenicamente e quantificados por espectrofotometria. O cálculo das velocidades instantâneas e específicas de produção de sulfetos permitiu avaliar de que maneira alguns parâmetros de crescimento microbiano podem afetar o metabolismo das BRS. A detecção de concentrações traço de sulfetos biogênicos pode ser realizada através de ensaios radiorespirométricos. Para isto, diluições em série de água do mar sintética com três amostras distintas foram avaliadas. Os testes realizados indicam que o acréscimo do tempo de incubação de cultura microbiana anaeróbia mista contribuiu para o aumento das capacidades de redução de sulfato, assim como o aumento das fontes de carbono. Ambas as técnicas provaram ser um rápido teste para a detecção de sulfetos biogênicos, particularmente aqueles associados aos produtos de corrosão, sendo uma ferramenta muito útil para monitoração e controle de tanques de armazenamento de água e óleo, plataformas continentais de petróleo e diversos tipos de reservatórios. O presente trabalho prevê a continuidade dos experimentos, através de avaliação de um maior universo de amostras da indústria do petróleo e medições menos espaçadas da técnica espectrofotométrica, além da avaliação radiorespirométrica em modo contínuo, evitando os efeitos inibitórios do H2S / Corrosion caused by biogenic H2S often results in extensive damage, being one of the main problems of petroleum industry. The objective of the present work was to evaluate microbial growth parameters and apply methodologies for sulfide detection by spectrometric at visible light and radiorespirometric techniques for estimate the metabolic activity, correlating with population of Sulfate Reducing Bacteria, through the More Probable Number (MPN) technique. Samples of formation water and SBR consortium were evaluated through drag of stable sulfides biogenically produced and quantified by spectrometry. The calculations of instant and specific rates of sulfide production allow evaluating how some microbial growth parameters may affect the SRB metabolism. The detection of trace concentrations of biogenic sulfides, undetectable by spectrometry technique, may be realized by radiorespirometric assays. For this step, serial dilutions of synthetic seawater with three distinct samples were evaluated. The realized test indicates that increasing the time of incubation of a mixed anaerobic microbial culture contributed to an increase in the capabilities of sulfate reduction, as well as the amount of carbon source. Both techniques proved to be a rapid test for the detection of biogenic sulfides, particularly those associated to corrosion products, being an useful tool for monitoring and controlling oil/water storage tanks, petroleum continental platforms and several types of reservoirs. The present work provides the continuous of the experiments, using a bigger universe of samples of petroleum industry and less spaced measuring of spectrometric technique, further the radiorespirometric evaluation in continuous mode, avoiding the H2S inhibitory effects

Comissão Nacional de Energia Nuclear / A corrosão causada por H2S biogênico frequentemente resulta em danos extensos na indústria do petróleo. O presente trabalho avaliou parâmetros de crescimento microbiano e aplicou metodologias de determinação de sulfetos por técnicas espectrofotométrica na região da luz visível e radiorespirométrica para avaliação da atividade metabólica, correlacionando com a população de bactérias redutoras de sulfato, determinada através da técnica do Número Mais Provável (NMP). Amostras de água de formação e consórcio de BRS foram avaliadas através do arraste de sulfetos estáveis produzidos biogenicamente e quantificados por espectrofotometria. O cálculo das velocidades instantâneas e específicas de produção de sulfetos permitiu avaliar de que maneira alguns parâmetros de crescimento microbiano podem afetar o metabolismo das BRS. A detecção de concentrações traço de sulfetos biogênicos pode ser realizada através de ensaios radiorespirométricos. Para isto, diluições em série de água do mar sintética com três amostras distintas foram avaliadas. Os testes realizados indicam que o acréscimo do tempo de incubação de cultura microbiana anaeróbia mista contribuiu para o aumento das capacidades de redução de sulfato, assim como o aumento das fontes de carbono. Ambas as técnicas provaram ser um rápido teste para a detecção de sulfetos biogênicos, particularmente aqueles associados aos produtos de corrosão, sendo uma ferramenta muito útil para monitoração e controle de tanques de armazenamento de água e óleo, plataformas continentais de petróleo e diversos tipos de reservatórios. O presente trabalho prevê a continuidade dos experimentos, através de avaliação de um maior universo de amostras da indústria do petróleo e medições menos espaçadas da técnica espectrofotométrica, além da avaliação radiorespirométrica em modo contínuo, evitando os efeitos inibitórios do H2S / Corrosion caused by biogenic H2S often results in extensive damage, being one of the main problems of petroleum industry. The objective of the present work was to evaluate microbial growth parameters and apply methodologies for sulfide detection by spectrometric at visible light and radiorespirometric techniques for estimate the metabolic activity, correlating with population of Sulfate Reducing Bacteria, through the More Probable Number (MPN) technique. Samples of formation water and SBR consortium were evaluated through drag of stable sulfides biogenically produced and quantified by spectrometry. The calculations of instant and specific rates of sulfide production allow evaluating how some microbial growth parameters may affect the SRB metabolism. The detection of trace concentrations of biogenic sulfides, undetectable by spectrometry technique, may be realized by radiorespirometric assays. For this step, serial dilutions of synthetic seawater with three distinct samples were evaluated. The realized test indicates that increasing the time of incubation of a mixed anaerobic microbial culture contributed to an increase in the capabilities of sulfate reduction, as well as the amount of carbon source. Both techniques proved to be a rapid test for the detection of biogenic sulfides, particularly those associated to corrosion products, being an useful tool for monitoring and controlling oil/water storage tanks, petroleum continental platforms and several types of reservoirs. The present work provides the continuous of the experiments, using a bigger universe of samples of petroleum industry and less spaced measuring of spectrometric technique, further the radiorespirometric evaluation in continuous mode, avoiding the H2S inhibitory effects