In electromagnetic launcher (EML) systems, the behavior of the materials and forces at the armature-rail interface involves fluid mechanics, electromagnetics, thermal effects, contact mechanics and deformation mechanics. These factors must interact successfully in order for a launch to be successful. A lubricant film either deposited on the rails prior to launch or injected from the armature during launch has been suggested as a means of improving the electrical conductivity of the rail-armature interface and of avoiding the occurrence of arcing. The fluid pressure generated by such film, together with the magnetic force, the contact force and the uneven temperature field in the armature, deforms the armature and changes the interface gap shape. An analytical model to study the interfacial behavior under these influences is necessary in order to predict the performance of a potential EML design and to provide optimization information. Studies of this interfacial behavior have been done by a number of researchers. However, many critical factors were not included, such as surface roughness, cavitation, injection, magnetic lateral force, interface deformation and thermal effects. The three models presented in this study investigate the influence of those factors on the EML interface problem. The magneto-hydrodynamic (MHD) model establishes a description of the lubrication process under electromagnetic stress but neglects interface deformation. The magneto-elastohydrodynamic (MEHD) model extends the MHD model by considering the lateral magnetic force, interface contact force and elastic deformation. Finally, the magneto-elastothermohydrodynamic (METHD) model adds the thermal effects to the deformation analysis. A coupled analysis of the interface behavior with the METHD model is developed and the history of a typical launch is studied. Detailed injection, lubrication and launch processes are revealed and the performance is predicted. A failed launch is simulated and the cause of failure is identified to be debris left on the rails. Several operation and design parameters, such as rail surface profile, electric current pattern, reservoir load, lubrication length, pocket size and geometry, injection conduit diameter, are analyzed and a recommended injection design procedure is developed. A scaling study is performed by doubling the dimensions to predict the scaling effects. In the end, the base case configuration and scaled configuration are optimized using the technique developed in this study.

The objective of this diploma thesis is to perform a conceptual lay-out of a small launcher. Re- quirements have been defined in order to realize this first preliminary study and design of a small launcher. In that frame, a MATLAB code has been written in order to simulate the rocket tra- jectories. An optimization program on launcher staging has been written as well. To validate this code, the VEGA and Ariane 5 launchers have been used. Then from studies on existing launchers, simulations have been performed in order to find an optimum small launcher and later on to design more precisely the small launcher. As a requirement an upper stage has been newly designed for the purpose of the study. At the end, two small launchers have been considered: a three-stage launcher using the Zefiro 23 as a first stage, the Zefiro 9 as a second stage, and an upper stage using a 3kN thrust engine; a two-stage launcher using the Zenit booster engine in the first stage, and an upper stage using a 22kN thrust engine.

Future magnetic fusion reactors such as tokamaks will need innovative, fast, deep-fueling systems to inject frozen deuterium-tritium pellets at high speeds and high repetition rates into the hot plasma core. There have been several studies and concepts for pellet injectors generated, and different devices have been proposed. In addition to fueling, recent studies show that it may be possible to disrupt edge localized mode (ELM) formation by injecting pellets or gas into the fusion plasma. The system studied is capable of doing either at a variety of plasma and pellet velocities, volumes, and repetition rates that can be controlled through the formation conditions of the plasma. In magnetic or inertial fusion reactors, hydrogen, its isotopes, and lithium are used as fusion fueling materials. Lithium is considered a fusion fuel and not an impurity in fusion reactors as it can be used to produce fusion energy and breed fusion products. Lithium hydride and lithium deuteride may serve as good ablating sleeves for plasma formation in an ablation-dominated electrothermal plasma source to propel fusion pellets. Previous studies have shown that pellet exit velocities, greater 3 km/s, are possible using low-z propellant materials. In this work, a comprehensive study of solid lithium hydride and deuteride as a pellet propellant is conducted using the ETFLOW code, and relationships between propellants, source and barrel geometry, pellet volume and aspect ratio, and pellet velocity are determined for pellets ranging in volume from 1 to 100 mm3. / Master of Science

The purpose of this project was to build an automated padel ball launcher, with specific objectives set at the beginning. The launcher needed to be accurate enough to allow for repetitive practice, automated to function as a practical tool, and include remote control for ease of use. To achieve accuracy, the construction was designed to ensure each shot was performed similarly. Automation was achieved through the ball feeding sequence, launching the ball in a consistent manner each time. Remote control was possible via a WiFi module controlling both the feeding mechanism and motors. The prototype was constructed with readily available materials due to project constraints. The final prototype met all objectives and was tested to gather results. The results were positive, indicating the project was successful. Future development is possible based on these results. / Syftet med detta projekt var att bygga en automatiserad padelbollsmaskin utefter en målsätning som sattes från början. Maskinen behövde vara tillräckligt noggrann för att tillåta repetitiv träning, automatiserad för att fungera som ett praktiskt verktyg och inkludera fjärrstyrning för att vara användarvänlig. För att uppnå noggrannhet designades konstruktionen för att se till att varje skott utfördes på liknande sätt. Automatisering uppnåddes genom bollmatningssekvensen, vilket även såg till att bollen skjöts på ett konsekvent sätt varje gång. Fjärrstyrningen var möjlig via en WiFi-modul som kontrollerade både matningsmekanismen och motorerna. Prototypen byggdes med lättillgängliga material på grund av projektets begränsningar. Den slutliga prototypen uppfyllde alla mål och testades för att samla in resultat. Resultaten var positiva, vilket indikerade att projektet var framgångsrikt. Framtida utveckling är möjlig baserat på dessa resultat.

This thesis derives working expressions from electromagnetic physical laws to gain a deeper understanding of the nature of railguns. The expressions are refined for ease of use and then compared to electromagnetic simulators that solve complex equations that arise from different rail geometry. Further simplifications lead to an expression for the final velocity of the projectile and showcase the importance of the system resistance to projectile flux gain ratio. A Simulink simulation then incorporates the resulting non-linear differential equations and approximates the projectile velocity over time based on physical dimensions and material properties. Some equations derived can be found in literature regarding the subject but often lack explanation. This work is intended to provide a thorough derivation of all the relative constituent relations between the critical characteristics of the gun such as the strength of the forces acting on the rail and projectile, rail current, and initial velocity of the projectile. This makes it easier to identify what influences acceleration of the projectile, how much bracing each rail needs, how much initial velocity to give the projectile, etc. Design options discussed besides the standard design include the augmented rail system, a magnetic shell design, and a “wrap around” design. The tradeoffs encountered in each design are discussed in length. Due to the lack of a sufficient power source during testing the projectile was unable to travel down the length of the rails due to metal binding, insufficient pulse duration, and too much circuit resistance. It was found that using copper tungsten for the rails ensures that the rails can withstand the arcing inflicted by the kilo-Ampere current along the rails very well compared to other materials. Also, the copper in the tungsten alloy ensures high conductivity while the tungsten provides structural integrity to the rails during arcing between them and the projectile. Frequency response of conductive projectiles is characterized and improvements such as laminated projectiles are suggested as solutions to mitigate eddy currents induced in the projectile and improve performance.

The design of complex systems such as a launcher, or subsystems like its pressurization system, is known to be fastidious and expensive especially in the space domain. However, the recent emergence of new actors in this domain has been a game changer, binding these systems to fulfil more and more requirements (cheap, efficient, rapidly produced, aesthetic, environmentally friendly…) in order to compete with the market. For these reasons, engineers now need more than ever to consider the full picture of a system or subsystem in order to optimize it. In this context, this document aims to present the method and the results obtained in the optimization of the pressurization system of a reusable rocket first stage named Themis 3. The modelling of the pressurization system has been realized through a software called Geeglee. In order to cover as many impacts of this system as possible, an important part of the rocket stage has been considered and modelled (from the pressurization gases to the propellant tanks, passing by the pressurant and propellant feeding lines). Three High Level Requirements (HLR) have been identified as of major importance for the trade-off in the design of the pressurization system: the total mass impact, the total Recursive Cost (RC) impact and the total Non-Recursive Cost (NRC) impact. This optimization has in particular permitted to confirm some well-known results, so to say that exogenous pressurization systems represent a smaller mass impact on the vehicle, at the expense of a higher RC compared with autogenous systems. / Utformningen av komplexa system, som till exempel en bärraket, eller delsystem som dess trycksättningssystem, är känd för att vara krävande och kostsam, särskilt inom rymdteknikområdet. Den senaste tidens uppkomst av nya aktörer på detta område har dock förändrat spelregler då dessa system tvingas uppfylla allt fler krav (billiga, effektiva, snabbt producerade, estetiska, miljövänliga etc.) kunna vara konkurrenskraftiga på marknaden. Av dessa skäl måste ingenjörer nu mer än någonsin beakta hela bilden av ett system eller delsystem för att kunna optimera det. I detta sammanhang syftar detta dokument till att presentera metoden och resultaten från optimeringen av trycksättningssystemet för en återanvändbar rakets första steg som heter Themis 3. Modelleringen av trycksättningssystemet har genomförts med hjälp av ett systemmodelleringsverktyg som kallas Geeglee. För att täcka in så många effekter av detta system som möjligt har en viktig del av raketsteget beaktats och modellerats (från trycksättningsgaserna till drivmedelstankarna, via tryck- och drivmedelsmatningsledningarna). Tre krav på hög nivå har identifierats som mycket viktiga för avvägningen vid utformningen av trycksättningssystem konstruktion: den totala masspåverkan, den totala icke-rekursiva kostnaden och den totala rekursiva kostnaden. Denna optimering har framför allt gjort det möjligt att bekräfta vissa välkända resultat, dvs. att exogena trycksättningssystem ger en mindre masspåverkan på fordonet, på bekostnad av en högre RC jämfört med autogena system.

A abordagem de linha de produtos de software oferece benefícios ao desenvolvimento de software como economia, qualidade e desenvolvimento rápido, pois se baseia em reuso de arquitetura de software mais planejado e direcionado a um domínio específico. Neste contexto, o gerenciamento da variabilidade é uma questão chave e desafiadora, já que esta atividade auxilia a identificação, projeto e implementação dos novos produtos derivados da linha de produtos de software. O objetivo deste trabalho é definir um processo de gerenciamento de variabilidade de linha de produtos de software. Este processo, denominado GVLPS, identifica a variabilidade, extraindo as variantes a partir de diagramas de casos de uso e modelando-as através de features, especifica a variabilidade identificada e utiliza como suporte, na criação de variantes, um mecanismo de variabilidade baseado em modelos de objetos adaptáveis e em reflexão. A aplicação do processo é realizada através de um estudo de caso sobre o software de um veículo espacial hipotético, o Lançador de Satélites Brasileiro (LSB). / The Software Product Line approach offers benefits such as savings, large-scale productivity and increased product quality to the software development because it is based on software architecture reuse which is more planned and aimed to a specific domain. The management of variability is a key and challenging issue, since this activity helps identifying, designing and implementing new products derived from software products line. This work defines a process for the variability management of software product line, called GVLPS. After modeling the variability, extracting the variants from use case diagrams and features, the next step is to specify the variability that was identified. Finally, the proposed process uses a variability mechanism based on adaptive object model and reflection as support in the creation of variants. The proposed process uses as case study the software system of a hypothetic space vehicle, the Brazilian Satellites Launcher (LSB).

A abordagem de linha de produtos de software oferece benefícios ao desenvolvimento de software como economia, qualidade e desenvolvimento rápido, pois se baseia em reuso de arquitetura de software mais planejado e direcionado a um domínio específico. Neste contexto, o gerenciamento da variabilidade é uma questão chave e desafiadora, já que esta atividade auxilia a identificação, projeto e implementação dos novos produtos derivados da linha de produtos de software. O objetivo deste trabalho é definir um processo de gerenciamento de variabilidade de linha de produtos de software. Este processo, denominado GVLPS, identifica a variabilidade, extraindo as variantes a partir de diagramas de casos de uso e modelando-as através de features, especifica a variabilidade identificada e utiliza como suporte, na criação de variantes, um mecanismo de variabilidade baseado em modelos de objetos adaptáveis e em reflexão. A aplicação do processo é realizada através de um estudo de caso sobre o software de um veículo espacial hipotético, o Lançador de Satélites Brasileiro (LSB). / The Software Product Line approach offers benefits such as savings, large-scale productivity and increased product quality to the software development because it is based on software architecture reuse which is more planned and aimed to a specific domain. The management of variability is a key and challenging issue, since this activity helps identifying, designing and implementing new products derived from software products line. This work defines a process for the variability management of software product line, called GVLPS. After modeling the variability, extracting the variants from use case diagrams and features, the next step is to specify the variability that was identified. Finally, the proposed process uses a variability mechanism based on adaptive object model and reflection as support in the creation of variants. The proposed process uses as case study the software system of a hypothetic space vehicle, the Brazilian Satellites Launcher (LSB).

The increasing market of small and affordable space systems requires fast and reliablelaunch capabilities to cover the current and future demand. This project aims to studyand implement guidance and control schemes for vertical ascent and descent phases ofa reusable launcher. Specifically, the thesis focuses on developing and applying ModelPredictive Control (MPC) and optimisation techniques to several kino-dynamic modelsof rockets. Moreover, the classical MPC method has been modified to include a decreasingfactor for the horizon used, enhancing the performance of the guidance and control.Multiple scenarios of vertical launch, landing and full fligth guidance on Earth and Mars,along with Monte Carlo analysis, were carried out to demonstrate the robustness of thealgorithm against different initial conditions. The results were promising and invite tofurther research.

The master's thesis deals with simultaneous film interpreting and pre-prepared electronic subtitles at film festivals in the Czech Republic. Simultaneous film interpreting used to be a widespread mode of audiovisual translation at film festivals. However, today it has been mostly replaced with subtitles; these are often pre-prepared electronic subtitles manually projected under the film screen by a so-called subtitle launcher. These types of audiovisual translation are generally characterized in the theoretical part of the thesis. In the empirical part, the research first focuses on film interpreting at the Karlovy Vary International Film Festival. As films are no longer interpreted at the festival, the research method of interviews with the then interpreters was chosen. Based on the information obtained from the interviews, it is described how films were interpreted and what working conditions interpreters had. General information on film interpreting was also gathered during the interviews. The second chapter of the empirical part deals with pre-prepared subtitles: first with the process of subtitle launching and subtitle launchers' working conditions, and then with the audience's opinion, which was elicited in a questionnaire survey at the Summer Film School Uherske Hradiste. The questionnaire...