Additive manufacturing (AM), also called 3D-printing, are technologies where parts are formed from the bottom up by adding material layer-by-layer on top of each other. Electron Beam Melting (EBM) is an AM technique capable of manufacturing fully solid metallic parts, using a high-intensity electron beam to melt powder particles in layers to form finished components. Compared to conventional machining, EBM offers enhanced efficiency for production of customized and patient specific parts such as e.g. dental prosthetics. However, dental prosthetics are challenging to produce by EBM, as their small sizes mean that mechanical and surface properties may be altered as part sizes decreases. The aim of this thesis is to gain new insights that could lead to optimization for production of small sized components in the EBM. The work is focused to understand the process-property relationships for small size components production. To improve the surface resolution and part detailing, a smaller sized powder was used for production and compared to parts made with standard sized powder. The surface-, chemical and mechanical properties were evaluated for parts produced with both types of powders. The results indicate that the surface roughness may be influenced by powder and build layer thickness size, whereas the mechanical properties showed no influence of the layer-wise production. However, the mechanical properties are dependent on part size. The outermost surface of the parts consists of a surface oxide dominated by TiO2, formed as a result of reaction between the surface and residual gases in the EBM build chamber. The surface oxide thickness is comparable to that of a conventionally machined surface, but is dependent on build height. This work concludes that the surface resolution and component detailing can be improved by various measures. Provided that proper process themes are used, the EBM manufactured material is homogenous with properties comparable to conventional produced titanium. It has also been shown that the material properties will be altered for small components. The results point towards different ways of optimizing manufacturing of dental prosthetics by EBM, which will make dental prosthetics available for an increased number of patients.

Chemnitz, Techn. Univ., Diss., 2003. / Auch im Shaker-Verl. ersch. u.d.Titel: Herstellung, Charakterisierung und Bewertung von leitfähigen Diffusionsbarrieren auf Basis von Ta, Ti und W für die Kupfermetallisierung von Siliciumschaltkreisen, 2004 (3-8322-2532-3).

La presente investigación pretende dilucidar ciertas relaciones entre los mecanismos operantes en un tipo de literatura contemporánea chilena que, particularmente, llama la atención por erigirse en una esfera genérica textual ambigua, a partir del criterio distintivo tradicional. Es decir que, los límites de tal distinción, en un segundo acercamiento al texto, se difuminan, configurando un discurso híbrido, que, en su propia actualización literaria, insta tácitamente al lector a dar un siguiente paso en la indagación de los presupuestos y enunciados latentes. Decimos “híbrido” en el sentido en que sus elementos discursivos provienen tanto de la literatura como de la historia . Probablemente nos preguntaremos cómo dos registros, aparentemente lejanos, pueden converger en un mismo ámbito textual, pues bien, intentaremos constatar que tal distancia se presenta solo a nivel de superficie, mientras que en profundidad, dichos elementos logran corresponderse e incluso identificarse. Baste decir que tal presunción se sustenta, básicamente, en que ambos registros comparten el ser sustancialmente discurso.

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L'étude présente est avant tout le résultat d'une préoccupation personnelle de longue durée, qui commence avec mes premières leçons de piano et mes tentatives de jouer la musique de Beethoven. Le désir de savoir autant que possible sur la personnalité, la vie, les événements et les situations qui ont conduit à la naissance d'une œuvre est apparu très tôt. Il est évident et simple à démontrer, par ses propres notes et les témoignages de ceux qui ont écrit sur lui depuis presque deux cents ans, que Beethoven a eu des circonstances extérieures, des événements et des occurrences sociales, même historiques, qui ont déclenché certains thèmes musicaux, auxquels son propre génie et sa sensibilité ont trouvé la forme d'expression qui nous est connue aujourd'hui. Ensuite, deuxièmement, il s'agit dans cette étude d'un engagement strictement théorique. Je souhaite exposer les liens formés le long des presque trois décennies de maladie, entre la déficience auditive et la création musicale de Beethoven. Au-delà de la situation de nature médicale qu'il a accueillie avec une explicable panique, avec un mélange d'impuissance et de dépression, qui l'ont mené au seuil du suicide, presque, environ l'année 1803, la perte de l'ouïe a ouvert un horizon agonique dans l'existence du compositeur, un horizon qui a marqué sa lutte avec le destin. Celui-ci est le thème, sa perception, qui le déterminera à assumer l'image et le rôle du Héros, du Titan tendu sous les épreuves sombres des machinations divines qu'il accueille avec courage et, des fois, même avec défi. C'est de ces tensions que jaillissent quelques-unes de ses œuvres les plus complexes, puissantes, expressives et novatrices, depuis la Symphonie no.3 et jusqu'à la 9ème, les sonates pour piano et certaines de ses compositions pour cordes. Le modèle héroïque a été sans doute salvateur, une circonstance d'émulation titanique qui a aidé Beethoven à mener si loin, dans le sens créatif, sa lourde et, en quelque sorte, ironique déficience. Il faut admettre, d'autre part, que, en dehors de ce modèle romantique de se rapporter au destin par le recours au Héros et au Titan - figures de la grandiose culture grecque classique - on a du mal à déceler la relation du compositeur avec Dieu dans le sens chrétien, sa manière d'intégrer une vision, un sens de la vie fondé sur celui-ci. Certes, Missa Solemnis en Ré majeur op.123, la Symphonie no.9 et quelques autres ouvrages ou parties d'ouvrages, entretiennent l'avis que Beethoven a composé, tout comme Bach, son modèle et maître favori, de la musique de glorification de Dieu. Et si cela est tout à fait vrai, alors notre mission de comprendre son passage par des modèles culturels et religieux si différents devient encore plus difficile. / This study is, above all, the outcome of a long-lasting personal concern that goes back to the period of my first music lessons and my attempts to play Beethoven's music on the piano. My passion for certain musical compositions, the care to interpret them in the way, with the sensitivity and in keeping with their creator's intentions might be translated as follows: 1 wish to perform as if he could hear me and could recognize himself in the music I performed. I was fi lied, at a very early age, with the desire to know as much as possible about his personality, his life, the events and the circumstances that led to the birth of his work. It is obvious and easy to prove, based on Beethoven's own notes and the testimonies of those who have written about him for nearly two hundred years, that there were external triggers, such as social and even historical events or happenings, which activated certain musical themes that his genius and sensitivity gave expression in the form known to us today. In this study, I will speak, at the appropriate time, about situations, contexts and events of this kind: family problems, like the affair involving his nephew Karl, or sentimental issues, like the "lmmortal Beloved" (Der Unsterbliche Geliebte), the drama entailed by hearing Joss, the evolution of event on the European stage during the Napoleonic and post­ Napoleonic periods, etc. Second, this study represents a strictly theoretical undertaking. I wish to present, according to my own understanding, the connections formed throughout the nearly three decades of disease between Beethoven's hearing impairment and his musical creation. Beyond the medical situation that he responded to with understandable panic, with a mixture of helplessness, tremor and depression, which brought him close to the brink of suicide in around the year 1803, the Joss of hearing opened an agonizing horizon in the composer's existence, a horizon against which he waged his battle with destiny. This is the theme, his perception, which led him to take on the image and role of a Hero, of a Titan, strained under the bleak attempts of the divine machinations that he met with courage and, sometimes, even with defiance. It was from these strains that some of his most complex, powerful, expressive and innovative works gushed forth, from his Third and Ninth Symphonies to the piano sonatas and several other compositions for strings. Beethoven was, according to Wagner's very suggestive comparison, the equivalent of Tiresias. Thus, shifting between levels of expression, he could hear pure music with an ear that was no longer disturbed or corrupted by outside sounds. The music he heard and transmitted gushed out of himself, from the depths of his being, which was marked by dignity and prophetic drama in equal measure. His internal hearing was already sensitive to the sounds of the World, to the rhythms of Phenomena, to the turmoil and syncopes of Life. Like Tiresias, Beethoven was a prophet who could hear, understand and transmit the mysterious music of the world to the future centuries. He could hear the music of paradise and convey it in the Pastoral Symphony, he could hear the sublime joy of human brotherhood and convey it at the end of the Ninth Symphony, he could hear the sounds of death and hell and convey them in the serious, funeral passages of the Eroica Symphony of the Hammerklavier Sonata. He could hear the ceaseless melody of life's flow through time, he could understand the sonata of nature, the dance of light, the verve of joy, but also the twilight, pain and night, the end. He could hear the music from which this universe of illusory, transient and capricious forms was made, this universe which we call reality. This, I believe, is the "Last" Beethoven.

Made available in DSpace on 2014-12-17T14:16:22Z (GMT). No. of bitstreams: 1 LucianaRS_Pre_textuais.pdf: 37160 bytes, checksum: 5c10ca3517f836e974edc672ecd286cb (MD5) Previous issue date: 2008-02-12 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The inorganic actives, represented mainly by microfine zinc oxide and titanium dioxide, have shown great potential to protect against large UV spectrum. The aim of this study is the development, characterization and analysis of stability in the short term of microemulsions containing inorganic fotoprotection agents. The microemulsions identified by the phases diagram containing the metallic oxides were produced by two different methods and subjected to the centrifugation test and thermal stress cycles, and subsequently characterized by macroscopic evaluation, test dilution, electrical conductivity, pH, particle size, and zeta potential. This study highlights the influence of the metal oxides addition in the structure and distribution of micelles in the microemulsions / Os agentes fotoprotetores inorg?nicos, representados principalmente pelo ?xido de zinco e di?xido de tit?nio microfinos, t?m mostrado grande potencial de prote??o contra amplo espectro de radia??o UV. O objetivo deste trabalho consiste no desenvolvimento, caracteriza??o e estudo de estabilidade a curto termo de microemuls?es contendo agentes fotoprotetores inorg?nicos. As microemuls?es identificadas pelo diagrama de fases e adicionadas dos ativos fotoprotetores foram elaboradas a partir de dois m?todos diferentes e submetidas ao teste de centrifuga??o e ciclos gelo-degelo, sendo posteriormente caracterizadas pela avalia??o macrosc?pica, teste de dilui??o, condutividade el?trica, pH, granulometria e determina??o de potencial zeta. Este estudo evidencia a influ?ncia da adi??o dos ?xidos met?licos na estrutura??o micelar e distribui??o de tamanho de part?culas das microemuls?es

Phase transitions and other intrinsic properties (shape, size, architecture) of molecularly structured aerosol particles are important for understanding their role in planetary atmospheres and for technical applications. By combining bath gas cooling with time resolved mid-infrared spectroscopy and modeling, information is obtained on dynamic processes and intrinsic properties of fluoroform and ethane aerosol particles. The distinct infrared spectral features of fluoroform aerosol particles make it a particularly suitable model system. Homogeneous crystallization rates of the sub-micron sized aerosol particles are determined (JV = 10⁸ - 10¹⁰ cm-³s-¹ or JS = 10³ – 10⁵ cm-²s-¹ at a temperature of T = 78 K), and the controversial question regarding volume versus surface nucleation in freezing aerosols is addressed. It is demonstrated that current state of the art measurements of droplet ensembles cannot distinguish between the two mechanisms due to inherent experimental uncertainties. The evolution of particle shape from spherical supercooled droplets to cube-like crystalline particles and eventually to elongated crystalline particles is recorded and analyzed in detail with the help of vibrational exciton model calculations. Phase behaviour of pure ethane aerosols and ethane aerosols formed in the presence of other ice nuclei under conditions mimicking Titan’s atmosphere provide evidence for the formation of supercooled liquid ethane aerosol droplets, which subsequently crystallize. The observed homogeneous freezing rates (JV = 10⁷ – 10⁹ cm-³s-¹) imply that supercooled ethane could play a similar role in ethane rich regions of Titan’s atmosphere as supercooled water does in the Earth’s atmosphere. / Science, Faculty of / Chemistry, Department of / Graduate

Bibliographische Beschreibung und Referat Falko Schlottig In der vorliegenden Arbeit wird die Moeglichkeit der anodischen Festkoerpersynthese in ausgewaehlten annaehernd nichtwaessrigen Systemen gezeigt. Die Synthesen wurden sowohl unter anodischen als auch unter anodischen Plasmabedingungen durchgefuehrt. Die entstehenden heterogenen Konversionsschichten wurden mit verschiedenen festkoerperanalytischen Methoden untersucht. Sie sind sind unter den vorgegebenen Darstellungsbedingungen aus nichtoxidischen und oxidischen Phasen zusammengesetzt. Die durchgefuehrten Untersuchungen beziehen sich hauptsaechlich auf die Synthese im System Dimethylacetamid/ Hexamethylentetramin/ KBF4 an Aluminium unter anodischen Plasmabedingungen und auf die Schichtbildung in Acetonitril an Titan unter anodischen Bedingungen. Die an Titan in Acetonitril synthetisierten Konversionsschichten wurden vorwiegend mit Elektronenbeugung und Photoelektronenspektroskopie untersucht. Die Schicht ist aus nitridischen, carbidischen und oxidischen Phasen aufgebaut. Die Struktur und Zusammensetzung der einzelnen Schichtphasen sind von der Synthesespannung abhaengig. Bei Ueberschreitung eines kritischen Potentials wird das bestehende Schichtsystem durch Plasma- und Pyrolysereaktionen modifiziert. Im System Dimethylacetamid/ Hexamethylentetramin/ KBF4 werden unter anodischen Plasmabedingungen an Aluminium kristalline AlF3 - Schichten gebildet, in die KF-Kristallite eingeschlossen sind. Dabei sind Schichtzusammensetzung und -morphologie von der Konzentration des Elektrolyten abhaengig. Waehrend der Plasmareaktion existiert ein Temperaturgradient in der Schicht. Eine nachfolgende thermische Behandlung der Schichtkomponenten unterhalb der eigentlichen Plasmatemperatur fuehrt zu einer Veraenderung der Schichteigenschaften.

EN The present diploma thesis is focused on optimization methods of titanium and phosphorus concentration for their use in the colloidal solution of TiO2 nanoparticles modified by bisphosphonates. For these analyses was used atomic absorption spectrometry with flame and electrothermal atomization. The characteristics of the two analytes were compared to two different spectrometers. Using the F-AAS technique on the GBC 933 AA spectrometer has been achieved a detection limit of 5,2 mg l-1 for titanium and a detection limit of 163 mg l-1 for the phosphorus. Using the ContrAA 700 spectrometer, F-AAS has been achieved an almost five times lower detection limit of 1,1 mg l-1 for titanium determination. For determination of phosphorus using this spectrometer, was obtained a similar value of 151 mg l-1 , as using the GBC 933 AA spectrometer. The determination of phosphorus by the ET-AAS technique using the ContrAA 700 spectrometer resulted in a detection limit of 1,23 mg l-1 , which is a significant difference compared to the flame system. It has been proved that optimized methods are consistent with the intention, which was confirmed by the analysis of real titanium and phosphorus samples in the colloidal solution of TiO2 nanoparticles modified bisphosphonates.

Da in der Natur die Festigkeit der Stoffe bzw. Werkstoffe mit deren Massendichte korreliert [1], bieten sich dem Werkstoffingenieur zwei Möglichkeiten das genannte Ziel zu erreichen: Entweder er reduziert die effektive Dichte bereits sehr fester Werkstoffe durch konstruktive bzw. geometrische Optimierungen, oder es gelingt sehr leichte Werkstoffe mit deutlich gesteigerter Festigkeit herzustellen. Die erstgenannte Verfahrensweise stellt zu großen Teilen ein konstruktives bzw. fertigungstechnisches Problem dar. Von werkstoffwissenschaftlichem Interesse ist deshalb nur die zweite Möglichkeit. Dabei sollen sämtliche derzeit bekannte festigkeitssteigernde Faktoren und möglicherweise auch deren Synergien genutzt werden um einen hochfesten Leichtbauwerkstoff herzustellen. Dazu muss gleichzeitig ein neuartiges Hochumformverfahren für Leichtmetallverbundwerkstoffe erarbeitet werden, das diesen Anforderungen entspricht und eine dafür geeignete Werkstoffkombination gefunden werden. Konventionelle Verfahren zur Hochumformung erlauben häufig nur unter erheblichem Mehraufwand die Verarbeitung von Verbundwerkstoffen, weshalb die Hochumformung von Leichtmetallverbundwerkstoffen zur Festigkeitssteigerung in der Literatur praktisch keine Rolle spielt. Deshalb soll in dieser Arbeit das Umformverfahren Rundkneten zur Anwendung kommen, das die Hochumformung auch sehr heterogener Werkstoffe erlaubt. Darüber hinaus wird eine zusätzliche positive Wirkung auf die Festigkeit durch eingebaute Grenzflächen auf den Gesamtverbund erwartet. Wie sich im Laufe der Arbeit heraus stellte, eignet sich das verwendete Verfahren nicht ausschließlich zur Festigkeitssteigerung von Verbundwerkstoffen. Durch die sehr regelmäßige und fraktale Anordnung der Komponenten im Gesamtverbund ergaben sich auch einige Anknüpfungspunkte, die weit über die Eignung im Sinne eines Leichtbauwerkstoffes hinaus gehen. Aus diesem Grund liegt der Schwerpunkt der Arbeit zwar auf der mechanischen Charakterisierung der hergestellten Verbunde, in Kapitel 6 werden aber auch weitere Nutzungsmöglichkeiten diskutiert. Die gewählte Materialkombination Titan-Aluminium ist als Beispiel zu verstehen. Prinzipiell ist das vorgestellte Verfahren auf viele weitere Materialkombinationen anwendbar, solange grundlegende umformtechnische Regeln beachtet werden. [1] Ashby, M. F.: Materials Selection in Mechanical Design. Heidelberg: Spektrum Akademischer Verlag, 2006. 648 S.