Additive manufacturing (AM) is a growing process interesting many companies in many industries. Thereare multiple processes within the familty of AM, but this study focuses on laser blown powder (LBP). LBP involves a laser beam focused on the substrate with powder being blown into the laser beam. The laser beam melts both the powder and the surface of the substrate and as the laser beam moves and the melt pool solidies it leaves a bead of solid material behind. These beads are placed next to each other creating a layer which are then stacked, building the wanted geometry. As the method develops new materials are tested and this study analyses Haynes 282 powder onto Inconel 718 substrate. Multiple process parameters are involved in the LBP method and this study focuses on the impact of laser effect and scanning speed. Each value on the process parameters was inspired by previous reports with similar equipment and process. The laser effect ranges from 1600 W to 700 W, scanning speed ranges between 900 mm/min to 300 mm/min and the powder feeding rate was also varied from 4 g/min to 3 g/min. Each sample was built as a single bead and a multilayer specimen, which is ve layers and 16 beadswide at the bottom and 12 beads wide at the top. When analyzing the samples images from microscopes were mostly used for obtaining results. An image software called ImageJ allowed measurements in an image to obtain penetration depth or primary dendrite arm spacing. ImageJ also allowed measurements of porosity by turning the image binary and calculate the fraction of white and black. The results consists of numerical values and visual analysis of the bead geometry, minimum and maximum penetration, microstructure, porosity, hardness and cracks. The results show an increased bead width around 2 mm to 4 mm and decreased bead height around 0,2 mm to 0,7 mm of single beads with increased laser effect. Increased maximum penetration depth around, 200 μm to 500 μm, withincreased laser effect. More remelt between each deposited layer causing longer dendrites with increasinglaser effect. Porosity is decreased with an increased laser power, going from 0,04 % to 0,15 %. No distinct difference in hardness is observed between the samples, ranging between 255 HV to 310 HV. It is believed that aging causes the increased hardness right above the fusion zone. Cracks were found between dendrites and is believed to be caused by Laves-phases. Most results are comparable to previous similar studies, both as trends and numerical values. The statistics of the study is limited, meaning that all results should not be taken as granted but as a general guide line for more studies. The purpose and goals of the study has been met and completed.

Influences on the interpretation of Tipton-Haynes State Historic Site have caused many alterations to the site and the presentation of its history. Scholars have described how public history sites have continually expanded their interpretations as growing desires and interests from external influences such as the general public, state agencies, and donors. However, Tipton-Haynes has also faced many internal influences. While the creators of the site aided in the limitation and exclusion of the site’s vital history, over time the involvement and opinions of the board of trustee members, directors, and staff shaped an increasingly inclusive and expansive interpretation of the site. Therefore, the experience at Tipton-Haynes suggests that scholars should also consider the innerworkings of a historic site and the opinions of not just the community but also the opinions and choices of the people involved in the site and its creation. The inclusivity allows for a more expansive history while also creating new connections between the history of Tipton-Haynes and the general public.

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The offshore oilfield industry is continuously developing unique and break-through technologies and systems to extract hydrocarbons from ever increasing ocean depths. Due to the extreme depths being explored presently, large anchors are being utilized to secure temporary and permanent facilities over their respective drilling/production site. A vertically loaded, torpedo-style, deepwater mooring anchor developed by Delmar Systems, Inc. is one of these anchors. The OMNI-Max anchor is an efficient, cost-effective alternative for use as a mooring system anchor intended for floating facilities. The OMNI-Max is designed to free-fall towards the ocean bottom and uses its kinetic energy for self-embedment into the soil, providing a mooring system anchor point. Values such as drag coefficient and terminal velocity are vital in predicting embedment depth to obtain the mooring capacity required by the floating facility. Two scaled models of the Mark I OMNI-Max anchor were subjected to a series of tests in the Haynes Coastal Engineering Laboratory at Texas A & M University to evaluate the overall drag coefficient and penetration depth. The 1/24 scale model was tested by measuring the amount of penetration into an artificial mud mixture. The 1/15 scale model was attached to a tow carriage and towed through a water-filled tank to measure the drag forces and evaluate the drag coefficient. The anchor terminal velocity was measured using underwater cameras to track the free fall of the model anchor through 15 ft of water inside the tow tank. The 1/24 scale model penetrated the mud an average of 22 inches from the leading tip of the anchor to the mud surface, approximately 1.5 anchor lengths. The penetration depth increased as impact velocity increased, while the penetration depth decreased as the fins were retracted. The 1/15 scale anchor was towed at 6 different velocities producing a varied total drag coefficient between 0.70 and 1.12 for Reynolds number flows between 3.08E 05 and 1.17E 06. The drag coefficient increased as the fins were retracted and when the mooring rope was attached. The 1/15 scale anchor was allowed to free-fall in the tow tank and obtained an average terminal velocity of and 14.6 feet per second. The drag coefficients ranged from 0.46 to 0.83, which increased as the fins were retracted. When using the results to estimate prototype sized anchor drag coefficient, the average value was estimated to be 0.75.

Haynes 282 is a gamma prime (𝛾′)-strengthened nickel base superalloy developed in 2005, exhibiting a good combination of high temperature properties and fabricability. Microstructural features such as 𝛾′ and carbides play an important role in deriving the mechanical properties of the alloy during heat treatment. As Haynes 282 is a relatively new alloy with insufficient literature availability, the present thesis is aimed at studying the evolution of microstructure for different heat treatment times and temperature with a special focus on 𝛾′ phase precipitation kinetics with different initial conditions for the material. The study is divided into two sections with objectives which are focused on the different ends to the heat-treatment time scales. The first objective of this study was to investigate γ' precipitation at short heat treatment times and develop Time-Temperature Precipitation (TTP) and Hardness (TTH) diagrams for Haynes 282 using a novel arc heat treatment. In this technique, a steady state temperature gradient, covering room temperature to liquidus, was created using stationary TIG arc on a disc mounted on a water-cooled chamber. Aged and solutionized samples were arc heat treated for 1.5 minutes, 30 minutes and 4 hours. The study was complemented with temperature modelling, thermodynamic calculations, and 𝛾′ precipitation simulation. A unique graded microstructure formed, consisting of dendritic region in fusion zone; dissolution area of all phases including MC carbides, grain boundary carbides, and 𝛾′; grain boundary carbide zone, 𝛾′ band; and base metal. 𝛾′ precipitate size increased with increasing time and temperature. 𝛾′ precipitation simulation model was developed, and it showed very good agreement with experimental results. Finally, the results were summarized in TTH and TTP diagrams. The second objective in this work was to study understand the coarsening behaviour of 𝛾′ phase with an initial pre-heat-treated GKN heat treatment using furnace heat treatment. Isothermal heat treatments for temperatures from 800°C to 1120°C and times from 30 seconds to 96 hours were performed. Morphological changes in 𝛾′ phase, particle size distribution, grain sizes and hardness on these isothermal heat-treated states are presented in this work. Additionally, A TC PRISMA precipitation model was evaluated to predict 𝛾′sizes and compare it with the measurements. It was concluded that complex initial microstructure, containing bimodal distribution of 𝛾′ precipitates, caused deviations between predicted and measured values, while the model, in the previous objective, predicted the sizes in close approximation to the experimental values. Therefore, further understanding and development of precipitation kinetics with the software should be done to achieve closer results to the experiment. / Haynes 282 är ett gamma prime (𝛾′) - förstärkt superlegering av nickelbas som utvecklades 2005 och uppvisar en god kombination av högtemperaturegenskaper och tygbarhet. Mikrostrukturella egenskaper såsom 𝛾′ och karbider spelar en viktig roll för att få de mekaniska egenskaperna hos legeringen under värmebehandling. Eftersom Haynes 282 är en relativt ny legering med otillräcklig litteraturtillgänglighet syftar den aktuella avhandlingen till att studera utvecklingen av mikrostruktur för olika värmebehandlingstider och temperatur med ett särskilt fokus på 𝛾′ fasutfällningskinetik med olika initiala förhållanden för materialet. Studien är uppdelad i två sektioner med mål som är inriktade på de olika ändarna på värmebehandlings tidsskalorna. Det första syftet med denna studie var att undersöka 𝛾′nederbörd vid korta värmebehandlingstider och utveckla Time-Temperature Precipitation (TTP) och Hardness (TTH) diagram för Haynes 282 med användning av en ny bågvärmebehandling. I denna teknik skapades en jämn temperaturgradient, som täcker rumstemperatur till liquidus, med användning av stationär TIG-båge på en skiva monterad på en vattenkyld kammare. Åldriga och lösningsbara prover bågvärmebehandlades under 1,5 minuter, 30 minuter och 4 timmar. Studien kompletterades med temperaturmodellering, termodynamiska beräkningar och 𝛾′utfällningssimulering. En unik graderad mikrostruktur bildad, bestående av dendritisk region i fusionszon; upplösningsområde för alla faser inklusive MC-karbider, korngränsande karbider och 𝛾′; korngränsen karbidzon, 𝛾′ band; och oädel metall. 𝛾′utfällningsstorlek ökade med ökande tid och temperatur. 𝛾′utfällningssimuleringsmodell utvecklades, och den visade mycket bra överensstämmelse med experimentella resultat. Slutligen sammanfattades resultaten i TTH- och TTP-diagram. Det andra syftet med detta arbete var att studera förstå det förgrovning beteendemönster hos 𝛾′ fasen med en initial förvärmebehandlad GKN-värmebehandling med ugnsvärmebehandling. Isotermiska värmebehandlingar för temperaturer från 800 ° C till 1120 ° C och gånger från 30 sekunder till 96 timmar utfördes. Morfologiska förändringar i 𝛾′fasen, partikelstorleksfördelning, kornstorlekar och hårdhet på dessa isotermiska värmebehandlade tillstånd presenteras i detta arbete. Dessutom utvärderades en TC PRISMA-nederbördsmodell för att förutsäga 𝛾′ storlekar och jämföra den med mätningarna. Det drogs slutsatsen att komplex initial mikrostruktur, innehållande bimodal fördelning av 𝛾′-fällningar, orsakade avvikelser mellan förutspådda och uppmätta värden, medan modellen i det tidigare målet förutspådde storleken i nära anpassning till experimentvärdena. Därför bör ytterligare förståelse och utveckling av utfällningskinetik med programvaran göras för att uppnå närmare resultat till experimentet.

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Dans le cadre du développement des Réacteurs à Haute Température (RHT), un des systèmes retenus pour la quatrième génération de centrale nucléaire, l’utilisation d’un cycle indirect est envisagée. Ce type d’installation, utilisant de l’hélium comme caloporteur, nécessite un échangeur intermédiaire de chaleur (Intermediate Heat eXchanger, IHX) le plus compact possible entre les circuits primaire et secondaire. Les contraintes imposées par la conception ainsi que les conditions sévères d’utilisation pour ce type d’installation (température maximale 850°C à 950°C, durée de vie 20000 h) ont orienté le choix des matériaux constitutifs de l’IHX vers deux alliages base nickel en solution solide : l’Inconel 617 et le Haynes 230. Le premier matériau a été largement étudié dans les années 1980 lors du projet allemand sur les RHT car possédant de bonnes propriétés mécaniques et en corrosion à haute température mais sa forte teneur en cobalt potentiellement activable est à considérer. Le Haynes 230, plus récent, possède des caractéristiques similaires à celles de l’alliage 617, le cobalt ayant été remplacé par du tungstène. L’objectif de cette thèse est d’étudier le comportement mécanique à haute température de ces deux alliages en relation avec les évolutions de leur microstructure. Les observations microstructurales à l’état de réception révèlent la présence de carbures primaires (M6C), la majorité étant répartie de manière homogène. Des carbures secondaires M23C6, peu nombreux, sont visibles à l’état de réception pour les deux matériaux. Les vieillissements thermiques imposés aux alliages à 850°C permettent une précipitation importante de carbures M23C6 sur les lignes de glissement et aux joints de grains, la taille de ces carbures augmentant et leur nombre réduisant avec la durée de traitement. A 950°C, l’évolution microstructurale conduit à une précipitation intragranulaire beaucoup plus limitée et à une évolution intergranulaire plus importante. Pour les deux matériaux, les observations de la microstructure et les résultats de dureté montrent que la majorité des évolutions microstructurales se produisent avant 1000 h aux deux températures étudiées. Les caractéristiques mécaniques de ces alliages ont été testées en traction, en fluage et en fatigue et fatigue relaxation. En particulier, les propriétés à 850°C et 950°C ont été étudiées pour différentes charges (en fluage), vitesses de déformation (en traction) et durées de relaxation (fatigue relaxation). Les effets d’un traitement initial ont également été étudiés, tels que l’effet d’un vieillissement thermique testé en fluage et traction et l’effet d’une prédéformation sur le fluage. Il ressort de cette étude que différents mécanismes de déformation sont mis en jeu successivement ou en parallèle au cours des essais réalisés. Ainsi, l’importance de la précipitation des carbures sur les propriétés mécaniques de l’Inconel 617 et du Haynes 230 a pu être démontrée, malgré leur statut d’alliages en solution solide. Par ailleurs, un même mécanisme thermiquement activé opère sur une très large gamme de vitesses de déformation, correspondant aux essais de traction, fluage et relaxation. Cette mise en relation entre microstructure et propriétés mécaniques permet de déterminer les avantages de chaque alliage ainsi que leurs limites d’utilisation dans le cadre de la fabrication d’un échangeur de chaleur de centrale nucléaire. / High Temperature Reactors (HTR), is one of the innovative nuclear reactor designed to be inherently safer than previous generation and to produce minimal waste. The most critical metallic component in that type of reactor is the Intermediate Heat eXchanger (IHX). The constraints imposed by the conception and the severe operational conditions (high temperature of 850°C to 950°C, lifetime of 20,000 h) have guided the IHX material selection toward two solid solution nickel base alloys, the Inconel 617 and the Haynes 230. Inconel 617 is the primary candidate alloy thanks to its good high temperature mechanical and corrosion properties and the large data base developed in previous programs. However, its high cobalt content has to be considered as an issue (nuclear activation). The more recent alloy Haynes 230, in which most of the cobalt has been replaced by tungsten, present characteristics similar to the 617 alloy. The objective of this thesis is to study the high temperature mechanical behaviour of both alloys in relation with their microstructural evolutions. The as received microstructural observations have revealed primary carbides (M6C). Most of this precipitates are evenly distributed in the materials. Few M23C6 secondary carbides are observed in both alloys in the as received state. Thermal ageing treatments at 850°C lead to an important M23C6 precipitation on slip lines and at grain boundaries. The size of this carbides increases and their number decreases with increasing ageing duration. The intragranular precipitation of secondary carbides at 950°C is more limited and the intergranular evolution more important than at 850°C. The microstructural observations and the hardness evolution of both alloys show that the main microstructural evolutions occur before 1,000 h at both studied temperatures. The mechanical properties of the Inconel 617 and the Haynes 230 have been studied using tensile, creep, fatigue and relaxation-fatigue tests. Particularly, the properties at 850°C and 950°C have been evaluated using several stress levels (creep), strain rates (tensile) and relaxation duration (fatigue). The effects of initial treatments have also been studied, i.e.ageing treatments effects on creep and tensile properties and cold-work effects on creep properties. At high temperature, the as received Inconel 617 does not show classical creep behaviour. This study shows the importance of the fast carbides precipitation on their mechanical properties, despite the fact that the Inconel 617 and the Haynes 230 are listed as solid solution alloys. Low cycle fatigue tests with and without holding time have been performed at 850°C under air and under vacuum on both alloys. The results showed that cyclic hardening, cyclic stability and life time are closely related to the duration of the holding time. Furthermore, a single thermally activated mechanism operates over a very wide range of strain rates, corresponding to tensile tests, creep and relaxation. The link between microstructure and mechanical behaviour presented in this thesis helps to determine the advantages as the operation limits of each alloy in order to manufacture a nuclear power plant heat exchanger

Jazz music is transmitted by aural and oral means. As recording and broadcast mediums became increasingly ubiquitous, starting in the mid twentieth-century, an ever greater proportion of jazz’s aural transmission would be mediated by these developing technologies. Many commentators address sound’s mediation from one state to another by identifying the resulting recording as an object. This object transcends temporal and spacial proximity, possessing inherent authority with implications for authorship, related work-concepts, and even issues of cultural assimilation. From a perspective informed by writings in musicology, philosophy, and sound studies, I examine recorded jazz music from the twentieth-century. I begin by positioning the history of jazz music in relation to the emergence of recording technologies to establish recordings as authoritative texts. I then translate (by transcription) primarily non-literate jazz recordings into the primarily literate discourse of musicology. In the course of examining music by James Moody, Eddie Jefferson, Bud Powell, Chick Corea, and others, I conclude that they all exemplify musical intertextuality. In some cases, technological mediation connects the texts. I then turn to an examination of recordings specifically. I begin by questioning musical notation as an adequate description of sound and move to developing a broader analytical framework. This thesis culminates with a comparison of Bud Powell’s 1949 recording of Bouncin’ With Bud and Chick Corea’s 1997 recording. Using the framework mentioned, disparate potentialities afforded by each recording’s mediation are connected to musical characteristics. / Graduate

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