Metal additive manufacturing is an important tool for the creation of cost effective and environmentally friendly components for the future of the aerospace industry. Newly developed methods such as Direct Energy Deposition, Laser Beam Wire (DEDLB/w) have the potential to quickly and effciently manufacture aircraft engine components of high quality when utilising the correct set of process parameters. Establishing these parameters is a challenging task as product defects can be diffcult to detect and localise during the DEDLB/w process. This thesis explores the possibility of detecting crack type defects during the additive manufacturing of Nickel-Based Superalloy components using in process acoustic emission inspection and hierarchical clustering to evaluate DEDLB/w process parameter sets. After observing numerous material depositions made using DEDLB/w, crack-like signals were observed and clustered using features derived from Acoustic Emission (AE) data. The results were then evaluated and validated using X-Ray and X-Ray Computed Tomography (µCT) inspection. Crack-like acoustic emissions were recorded from depositions in which cracks were later found using X-rayand µCT inspection, and these emissions were successfully clustered over multiple depositions using statistical analysis and agglomerative clustering.

The Auroral Large Imaging System (ALIS) was proposed in 1989 by Åke Steen as a joint Scandinavian ground-based nework of automated auroral imaging stations. The primary scientic objective was in the field of auroral physics, but it was soon realised that ALIS could be used in other fields, for example, studies of Polar Stratospheric Clouds (PSC), meteors, as well as other atmospheric phenomena. This report describes the design, operation and scientic results from a Swedish prototype of ALIS consisting of six unmanned remote-controlled stations located in a grid of about 50 km in northern Sweden. Each station is equipped with a sensitive high-resolution (1024 x 1024 pixels) unintensified monochromatic CCDimager. A six-position filter-wheel for narrow-band interference filters facilitates absolute spectroscopic measurements of, for example, auroral and airglow emissions. Overlapping fields-of-view resulting from the station baseline of about 50 km combined with the station field-of-view of 50° to 60°, enable triangulation as well as tomographic methods to be employed for obtaining altitude information of the observed phenomena. ALIS was probably one of the first instruments to take advantage of unintensi- fied (i.e. no image-intensifier) scientific-grade CCDs as detectors for spectroscopic imaging studies with multiple stations of faint phenomena such as aurora, airglow, etc. This makes absolute calibration a task that is as important as it is dificult. Although ALIS was primarily designed for auroral studies, the majority of the scientific results so far have, quite unexpectedly, been obtained from observations of HF pump-enhanced airglow (recently renamed Radio-Induced Aurora). ALIS made the first unambiguous observation of this phenomena at high-latitudes and the first tomography-like inversion of height profiles of the airglow regions. The scientific results so far include tomographic estimates of the auroral electron spectra, coordinated observations with satellite and radar, as well as studies of polar stratospheric clouds. An ALIS imager also participated in a joint project that produced the first ground-based daytime auroral images. Recently ALIS made spectroscopic observations of a Leonid meteor-trail and preliminary analysis indicates the possible detection of water in the Leonid.

This thesis is a continuation of design automation studies within research projects financed by VINNOVA (the Swedish Governmental Agency for Innovation Systems) and Knowledge foundation that contributed to the development of producibility assessment system at a global aerospace products supplier, GKN Aerospace Sweden. A case study was carried at the company on Turbine Rear Structure (TRS) component design of a jet engine with the main objective to evaluate weld producibility assessment tools and to demonstrate system’s performance in multi-disciplinary design environment. The context of this thesis is a set-based product design development where several studies, i.e. thermal, structural, aerodynamic etc. are carried concurrently to gather knowledge between their parameter relations. The thesis contributes to the goal of fully integrated producibility assessment in multi-disciplinary studies to support product development process. The problems encountered during the thesis execution involved systematic analysis setup to extract and verify CAD geometry data, assessment of meaningfulness of producibility indicators, development of semi-automated data post-processing module and relating product design to its manufacturing aspects. Commercial and in-house developed software were used extensively to demonstrate the results of the system with the help of continuous company support to mitigate indispensable bottlenecks along the way. The work has led to systematic improvements, determined assessment limitations and most relevant weld producibility aspects. Collected feedback to evaluate prepared demonstrator showed promising results to support product design decisions considering both performance and producibility.

This thesis contains the results of optical flame emission measurements of the Vulcain 2.1engine and the plasma emission spectroscopy of the Lumen Project engine. The plume spectroscopyis analyzed, ordered and studied in detail to offer the best possible molecular composition.The main focus relied on the hydroxide radical, blue radiation and other moleculesanalysis of the intensities encountered during the tests. The plasma emission spectroscopy isfocused on the determination of the plasma temperature value in LIBS measurements. Thehydrogen plasma temperature determination of the local thermodynamic equilibrium, followedby the carbon and sequentially oxygen plasma is obtained. The quality of the LTE isto be determined to judge the truthworthness of the determined temperatures. Both the testsare analyzed thanks to the use of spectrographs, cameras and dedicated software for opticalapplications. The results related to the Vulcain 2.1 LOX/LH2 engine showed the evolutionof the plume in different ROF or pressure variations. Furthermore, the results of the LumenProject LOX/methane engine led to the determination of the plasma temperatures and a firstestimation of the LTE quality. / Die vorliegende Arbeit präsentiert die Ergebnisse der Abgasstrahlspektroskopie des H2/LOXVulcain 2.1 Triebwerks und der Zündplasma Spektroskopie des CH4/LOX Triebwerks desLUMEN Projektes. Die Abgasstrahlspektroskopie wurde analysiert und im Detail untersuchtum die am besten passende molekulare Zusammensetzung herauszuarbeiten. DasHauptaugenmerk liegt dabei auf dem Hydroxyl- Radikal, der Blauen Strahlung und molekularerIntensitätsanalyse. Bei der Zündplasmaanalyse liegt der Fokus auf der Bestimmungdes LTE Zustands (Lokales thermodynamisches Gleichgewicht) in LIBS. Die Temperaturdes Wasserstoff-, Kohlenstoff und Sauerstoffplasmas wird herangezogen, um die Qualitätdes LTE Zustands zu beurteilen. Für die Testdurchführung wurden Spektrographen, Kamerasund bestimmte Auswertungstools für optische Anwendungen benutzt. Das Verhaltendes Vulcain 2.1 Abgasstrahls abhängig von verschiedenen ROF und Druckstufen ist in denErgebnissen beschrieben. Für das LUMEN Triebwerk konnten erste Zündplasmatemperaturenbestimmt werden und geben einen Rückschluss auf die Qualität des LTE.

<p>Humanity has always dreamed about a better world. These dreams has manifested themselves in the vision of Utopia - the good place, but also the non-existing place. Up until World War II man still wrote optimistic descriptions of this ideal world, and spread the idea through literature. In the aftermath of the atomic bomb and under the influence of the cold war, these publications seized to surface in literary surroundings. Despite this utopia did not die - it has only changed. Today you can find utopia, not primarily in books, but in Science Fiction. TV’s biggest Science Fiction-series, Star Trek, is perhaps the best example of this. The Master's thesis "Utopia Trek - a travel through Star Trek with the concept of utopia" takes you through the history of utopia and into its new habitat, Star Trek, where the essence of a utopia for the 21th century is found, discussed and reevaluated.</p> / <p>Mänskligheten har alltid drömt om en bättre värld. Dessa drömmar har manifesterats i visionen om Utopia - den goda platsen, men också platsen som inte existerar. Fram till andra världskriget skrev man fortfarande optimistiska beskrivningar av denna idealvärld, och spred idén via litteraturen. Efter hotet från atombomben och under påverkan av det kalla kriget, slutade dessa publikationer att dyka uppi litterära sammanhang. Trots detta dog inte drömmen utopia - det har bara förändrats. Idag kan man finna utopia, inte företrädesvis i böcker, utan i science fiction. Tv:s största science fiction-serie, Star Trek, är kanske det bästa exemplet på detta. Magisteruppsatsen "Utopia Trek - utopibegreppets resa genom Star Trek" tar dig genom utopias historia och in i dess nya hemvist, Star Trek, där essensen av ett utopia för 2000-talet upptäcks, diskuteras och omvärderas. </p>

<p>This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two specific physical systems are considered, namely artificially excited magnetic field-aligned irregularities (striations) and naturally excited lower hybrid solitary structures (LHSS). Striations are mainly density depletions of a few percent that are observed when a powerful electromagnetic wave, a pump wave, is launched into the ionosphere. The striations are formed by upper hybrid (UH) oscillations that are localized in the depletion where they are generated by the linear conversion of the pump field on the density gradients. However, the localization is not complete as the UH oscillation can convert to a propagating electromagnetic Z mode wave. This process, termed Z mode leakage, causes damping of the localized UH oscillation. The Z mode leakage is investigated and the theory predicts non-Lorentzian skewed shapes of the resonances for the emitted Z mode radiation. Further, the interaction between individual striations facilitated by the Z mode leakage is investigated. The LHSS are observed by spacecraft in the ionosphere and magnetosphere as localized waves in the lower hybrid (LH) frequency range that coincides with density cavities. The localized waves are immersed in non-localized wave activity. The excitation of localized waves with frequencies below LH frequency is modelled by scattering of electromagnetic magnetosonic (MS) waves off a preexisting density cavity. It is shown analytically that an incident MS wave with frequency less than the minimum LH frequency inside the cavity is focused to localized waves with left-handed rotating wave front. In addition, the theory is shown to be consistent with observations by the Freja satellite. For frequencies between the minimum LH frequency inside the cavity and the ambient LH frequency, the MS wave is instead mode converted and excites pressure driven LH oscillations. This process is studied in a simplified geometry.</p>

This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two specific physical systems are considered, namely artificially excited magnetic field-aligned irregularities (striations) and naturally excited lower hybrid solitary structures (LHSS). Striations are mainly density depletions of a few percent that are observed when a powerful electromagnetic wave, a pump wave, is launched into the ionosphere. The striations are formed by upper hybrid (UH) oscillations that are localized in the depletion where they are generated by the linear conversion of the pump field on the density gradients. However, the localization is not complete as the UH oscillation can convert to a propagating electromagnetic Z mode wave. This process, termed Z mode leakage, causes damping of the localized UH oscillation. The Z mode leakage is investigated and the theory predicts non-Lorentzian skewed shapes of the resonances for the emitted Z mode radiation. Further, the interaction between individual striations facilitated by the Z mode leakage is investigated. The LHSS are observed by spacecraft in the ionosphere and magnetosphere as localized waves in the lower hybrid (LH) frequency range that coincides with density cavities. The localized waves are immersed in non-localized wave activity. The excitation of localized waves with frequencies below LH frequency is modelled by scattering of electromagnetic magnetosonic (MS) waves off a preexisting density cavity. It is shown analytically that an incident MS wave with frequency less than the minimum LH frequency inside the cavity is focused to localized waves with left-handed rotating wave front. In addition, the theory is shown to be consistent with observations by the Freja satellite. For frequencies between the minimum LH frequency inside the cavity and the ambient LH frequency, the MS wave is instead mode converted and excites pressure driven LH oscillations. This process is studied in a simplified geometry.

Humanity has always dreamed about a better world. These dreams has manifested themselves in the vision of Utopia - the good place, but also the non-existing place. Up until World War II man still wrote optimistic descriptions of this ideal world, and spread the idea through literature. In the aftermath of the atomic bomb and under the influence of the cold war, these publications seized to surface in literary surroundings. Despite this utopia did not die - it has only changed. Today you can find utopia, not primarily in books, but in Science Fiction. TV’s biggest Science Fiction-series, Star Trek, is perhaps the best example of this. The Master's thesis "Utopia Trek - a travel through Star Trek with the concept of utopia" takes you through the history of utopia and into its new habitat, Star Trek, where the essence of a utopia for the 21th century is found, discussed and reevaluated. / Mänskligheten har alltid drömt om en bättre värld. Dessa drömmar har manifesterats i visionen om Utopia - den goda platsen, men också platsen som inte existerar. Fram till andra världskriget skrev man fortfarande optimistiska beskrivningar av denna idealvärld, och spred idén via litteraturen. Efter hotet från atombomben och under påverkan av det kalla kriget, slutade dessa publikationer att dyka uppi litterära sammanhang. Trots detta dog inte drömmen utopia - det har bara förändrats. Idag kan man finna utopia, inte företrädesvis i böcker, utan i science fiction. Tv:s största science fiction-serie, Star Trek, är kanske det bästa exemplet på detta. Magisteruppsatsen "Utopia Trek - utopibegreppets resa genom Star Trek" tar dig genom utopias historia och in i dess nya hemvist, Star Trek, där essensen av ett utopia för 2000-talet upptäcks, diskuteras och omvärderas.

Virtual reality (VR) är ett begrepp som blivit allt mer välkänt de senaste åren. VR kan beskrivas som en datorgenererad virtuell omvärld som användaren omsluts av. VR-miljön upplevs genom människans sinnen såsom syn, hörsel och känsel.Syftet med examensarbetet är att undersöka hur realistisk en kommersiellt tillgänglig VR-flygsimulator upplevs av piloter och undersöka om VR-teknik kan vara ett användbart läroverktyg för t.ex. flygskolor. VR-tekniken har under de senaste åren utvecklats väldigt mycket vilket gjort att många av de implementations svårigheter som VR-tekniken inneburit till stor del lösts. Nya helintegrerade head mounted displays (HMD) med inbyggd kompatibilitet gör att integreringsproblemen nästan helt försvunnit. Eftersom VR-tekniken nu är mer tillgänglig och lätthanterlig ligger det helt rätt i tiden att undersöka hur VR-teknik kan användas inom flygbranschen.Metoden för examensarbetet inleddes med informationsinsamling om VR-teknik och traditionella flygsimulatorer. Utifrån denna information skapades sedan en undersökning som bestod av två delar. Den första delen var ett experiment med en VR-flygsimulator och den andra delen var en intervju som utfördes direkt efter experimentet. Sju stridspiloter deltog i undersökningen.Resultaten av undersökningen visar att VR-flygsimulatorer upplevs som mer realistiska jämfört med traditionella flygsimulatorer. Undersökningen tyder också på att VR-teknik kan vara ett bra läroverktyg om de problem som identifierats lösts på ett tillfredsställande sätt. / Virtual reality (VR) is a rising phenomenon that has skyrocket in popularity the past year. VR is often referred to as a computer generated virtual environment the user gets immersed in. The VR environment is experienced through different types of sensory stimuli.The purpose of this thesis is to examine how realistic a commercially available VR flight simulator is being perceived by real pilots as well as examine if VR technology could be a viable educational tool for flight schools. The motivations of this thesis are the facts that the VR-technology has advanced in a quick phase. Many of the past difficulties with implementing VR technology have been addressed with new fully integrated head mounted displays therefor capability issues are no longer a big problem. Because of the simplicity of new VR-systems it’s a good time to investigate VR uses and how it compares to traditional flight simulator techniques.The method used for the thesis started with collecting information about VR technology and traditional flight simulators. With that information a survey consisting of two parts was created. The first part was an experiment with a VR flight simulator, and the second part was an interview conducted directly after the experiment. Seven jet fighter pilots participated in the survey.Our results show that a VR flight simulator is perceived as more realistic compared to a traditional flight simulator. It is also shown that VR technology could be a good educational tool if some of the issues that were found are resolved or improved upon.

The aerospace industry is constantly striving to becoming more economical and environmentally friendly. One of many efforts to achieve this is the Lightcam project which in this case is evaluating the use of additive manufacturing in the form of electron beam melting in conjunction with the nickel-based superalloy, Alloy 718. This combination is not fully explored and examined. For this purpose, a demonstrator vane was produced and it was subsequently evaluated in this thesis. The evaluation was performed in as-built condition and was divided in non-destructive testing, evaluation of these methods and metallographic review to confirm the results, and potentially revealing more properties. The non-destructive testing was performed using conventional radiography and computed tomography. Both methods struggled to deliver complete and reliable results, for varying reasons. Radiography could deliver results of the whole vane, but these were impossible to evaluate due to the rough surface created by the electron beam melting process. The computed tomography on the other hand was not affected by the rough surface and produced usable, though not complete, results of the vane. The reason for the computed tomography’s inability to deliver complete results was the material, varying thickness and complex geometry of the vane. As a complement and to verify the results from the non-destructive testing, a metallographic examination was conducted. These tests were conducted with the aim of answering the following three questions:  What non-destructive testing methods are suitable to evaluate Alloy 718 components manufactured with electron beam melting? - Neither radiography nor computed tomography are suitable as a sole evaluation method, for various reasons. All surface dependent methods were deemed unsuitable without testing due to the rough surface. What types of defects and in what quantity can they be found in the produced vane? - Defects found are: Porosity and lack of fusion, both found as internal and partially external and in varying sizes. Where are the defects located? - Pores are mainly found in the center of sections modeled to a 3mm thickness. Lack of fusion was found between build layers in all thicknesses. Apart from these results, hardness was found to vary depending on build height, increasing from the bottom towards the top. Microstructure was also found to vary with the build height, but always consisting of either equiaxed or columnar grains. / Lightcam