Haptic interfaces are robotic force-feedback devices that give the user a sense of touch as they interact with virtual or remote environments. These interfaces act as input devices, mapping the 3-dimensional (3D) motions of the user's hand into 3D motions in a slave system or simulated virtual world. A major challenge in haptic interfaces is ensuring that the user's experience is a realistic depiction of the simulated environment. This requires the interface's design to be such that it does not hinder the user's ability to feel the forces present in the environment. This "transparency" is achieved by minimizing the device's physical properties (e.g., weight, inertia, friction). The primary objective of the work is to utilize compliant mechanisms as a means to improve transparency of a haptic interface. This thesis presents work toward the design of a fully compliant mechanism that can be utilized in haptic interfaces as a means to reduce parasitic forces. The approach taken in this work is to design a series of mechanisms that when combined act as a statically balanced compliant joint (SBCJ). Simulated and experimental results show that the methods presented here result in a joint that displays a significant decrease in return-to-home behavior typically observed in compliant mechanisms. This reduction in the torque needed to displace the joint and the absence of friction suggest that the joint design is conducive to the methods previously proposed for increasing transparency in haptic interfaces.

In the development of battery electric trucks is one of the main concerns how to minimize the energy consumption of all the different subsystems on the truck. One of these energyconsuming systems is the active cab suspension. The load sensing (active) cab systems used today is using pressurized air, pneumatics, to keep the cab at correct ride height. Currently is this pressurized air produced with a big, bulky and heavy compressor that continuously is running to compress air for multiple different subsystems. The alternative to the load sensing active cab suspension is to use non-load sensing (passive) suspension. This option is limiting the comfort and appearance of the cab but is neither using any energy. The goal of this master thesis is to find a suspension solution that is both load sensing and energy-efficient. To find a suitable load sensing solution was cab suspension system on other types of heavy machines inspected, together with suspension systems overall. There could be seen that the use of hydraulics gave the adjustability needed, without consuming any energy when the adjustments had been done. The system could also be very compact. It is easy to adapt the existing suspension components to work together with the hydraulic cylinders, and the hydraulic suspension systems have the possibility to be merged with other hydraulic systems on the truck. / I utvecklingen av el- och batteridrivna lastbilar är en stor del av utmaning att minimera energianvändningen hos lastbilens alla olika delsystem, där ibland hyttfjädringen. Dagens lastkännande (aktiva) fjädringssystem på lastbilshytter drivs med tryckluft och arbetar kontinuerligt med att hålla lastbilshytten på rätt höjd. Tryckluften kommer ifrån en stor och tung kompressor som ständigt arbetar för att komprimera luft till lastbilens alla olika delsystem. Alternativet till den aktiva lastkännande hyttfjädringen är att använda en icke lastkännande (passiv) fjädring. Detta begränsar dock lastbilens komfort och utseende, men förbrukar heller ingen energi. Målet med detta examensarbete var att finna en fjädringslösning som både är lastkännande och energieffektiv. För att hitta en lämplig lastkännande lösning gjordes en grundlig undersökning av hyttfjädringslösningar på andra tunga fordon, samt olika fjädringssystem överlag. Det visade sig att användandet av hydraulik ger en tillfredsställande justerbarhet, utan att förbruka någon energi när systemet är i vila (inte aktivt justerar). Systemet skulle även kunna göras mycket kompakt. Det är lätt att anpassa dagens befintliga fjädringskomponenter för att kunna fungera ihop med justerbara hydraulcylindrar, och fjädringens hydraulsystem skulle kunna drivas ihop med övriga hydraulsystem på lastbilen.

The objective of this research is to determine the three-dimensional stiffness matrix of a rectangular cross-section helical coil compression spring. The stiffnesses of the spring are derived using strain energy methods and Castigliano's second theorem. A theoretical model is developed and presented in order to describe the various steps undertaken to calculate the spring's stiffnesses. The resulting stiffnesses take into account the bending moments, the twisting moments, and the transverse shear forces. In addition, the spring's geometric form which includes the effects of pitch, curvature of wire and distortion due to normal and transverse forces are taken into consideration. Similar methods utilizing Castigliano's second theorem and strain energy expressions were also used to derive equations for a circular cross-section spring. Their results are compared to the existing solutions and used to validate the equations derived for the rectangular cross-section helical coil compression spring. A finite element model was generated using IDEAS (Integrated Design Engineering Analysis Software) and the stiffness matrix evaluated by applying a unit load along the spring's axis, then calculating the corresponding changes in deformation. The linear stiffness matrix is then obtained by solving the linear system of equations in changes of load and deformation. This stiffness matrix is a six by six matrix relating the load (three forces and three moments) to the deformations (three translations and three rotations). The natural frequencies and mode shapes of a mechanical system consisting of an Additional mass and the spring are also determined. Finally, a comparison of the stiffnesses derived using the analytical methods and those obtained from the finite element analysis was made and the results presented. / Master of Science

The dissertation examines the Student Construction Brigade Movement (SCBM) in the context of Soviet internationalism and the Cold War and portrays it as one of the most unique youth movements in the world at that time. Under the umbrella of the SCBM and in the name of internationalism, students from both socialist and non-socialist countries voluntarily expressed a desire to engage in construction and agricultural work activities as well as cultural exchange. While examining these interactions, I argue that during the Cold War, global youth emerged as one key agent of internationalism through cooperative economic, political, and cultural activities on construction sites around the world. My research not only identifies the Soviet state’s goals in the SCBM (such as ideological indoctrination and demonstration of Soviet influence in beyond the country’s borders), but also reveals that the lived experience of the student exchange went far beyond politics or economics. Students of different nationalities and cultures directly communicated with each other, shared their worldviews, and created a positive basis for expanding their professional and personal contacts.

Flexographic printing involves driving a paper substrate through the gap between two cylinders, where one of the cylinders has a print form layer covered in ink. The ink transfer from the print form to the paper is dependent on the pressure between the paper substrate and the cylinders. Knowledge about how the paper substrate reacts to compression is therefore important when aiming for high quality flexography printing. In this project the paper substrate in focus is corrugated board consisting of a top liner, a bottom liner and a fluted paper material in between the liners. To gain knowledge about the compression dynamics of the boards they are subjected to compression experiments with and without print form. The compression experiments are filmed and the videos are then analyzed using thresholding and tracking methods. The developed thresholding method is able to measure the thickness of each material separately in each frame while the developed tracking method is able to track the movement of the top and bottom metal blocks compressing the materials. The strains calculated from the image analysis measurements are then used as input values to the Maxwell spring-dashpot model with the intention of modelling the stress. Analysis of the compression experiment videos shows that the material properties of thecorrugated board may not be constant for the duration of the compression. This is because the fluting changes its shape when being compressed. Comparing the modelled stress to the stress measured by the press used in the experiments shows that the Maxwell spring-dashpot model is not able to model the stress accurately when the corrugated board goes through multiple stages of compression. The model works better for compression where the shape of the fluting is not significantly changed.

American Geopolitical Culture strongly rejects the concept of spheres of influence, but great power competition often dictates a tacit acceptance of rival powers' privileged zones of control. During the Cold War, the Soviet Union sought to maintain a sphere of influence along its border, and on multiple occasions resorted to the use of force to maintain control over foreign states. How did the United States react to the Soviet use of force in sovereign territory that fell within the Soviet privileged spheres of influence? This paper looks at three case studies, the Hungarian Revolution, the Prague Spring, and the Soviet Invasion of Afghanistan, and provides an analysis of the American foreign policy response, and the geopolitical and cultural values that informed policymakers' decision-making. Despite the limited interventions pursued by the United States, the United States constantly sought to undermine Soviet efforts to maintain a sphere of influence. In Hungary and Czechoslovakia, the United States prioritized long-term strategies on a global scale to weaken the Soviet Union in lieu of tactical interventions in opposition to the Soviet use of force. In Afghanistan, the United States continued to maintain its long-term strategies, while taking advantage of unique local factors to place additional strain on the Soviet Union. Across all three case studies the United States consistently pursued strategies that sought to weaken the Soviet Union as a whole, rather than just target individual spheres of influence. / Doctor of Philosophy / This dissertation examines the American response to the Soviet use of force within its spheres of influence during the Cold War. American politicians have strongly rejected the validity of spheres of influence and consider them to be a form of imperialism that undermines a state's sovereign right to govern its own affairs. During the Cold War, the Soviet Union used military force to exert control over spheres of influence in Hungary, Czechoslovakia, and Afghanistan. The American response to each of these case studies varied. In Hungary and Czechoslovakia, the United States actively avoided intervening against the Soviet invasion, while in Afghanistan the United States provided extensive aid in the form of weapons, training, and intelligence. What explains the difference in the American approach to each of these case studies? This dissertation argues Soviet sphere of influence dynamics were stronger in Hungary and Czechoslovakia, which acted as a deterrent to any American intervention. Rather than engaging the USSR in its established spheres of influence, the United States prioritized opposing Soviet expansion elsewhere while propagandizing Soviet brutality to sway world opinion away from the Soviet Block. In Afghanistan, Soviet influence was considerably weaker, allowing the United States greater opportunities to contest the Soviet invasion directly.

This qualitative research aims to understand better how the multi-dimensional autonomy facilitated by social media activism influenced the dynamics of the Arab Spring, with a particular focus on the Egyptian Revolution of 2011. Based on semi-structured interviews with earlier Egyptian activists, social media significantly provided individuals with platforms to express their opinions more freely, engage in dialogue, and foster a sense of solidarity and empowerment, which enhanced their feeling of autonomy. Moreover, social media provided safe spaces and fostered a sense of unity and collective strength among activists. On the other side, activists faced challenges related to misinformation and censorship, which has affected interviewees’ individual autonomy negatively. This research also highlights the concept of liberty as non-domination and the need for individuals to be free from arbitrary control or interference by others, allowing them to act autonomously. Based on the interviews, the activists faced various forms of domination and control, such as government surveillance and harassment, which limited the extent to which social media could provide a platform for liberty as non-domination. However, the activists demonstrated resilience and adaptability in these challenges.

This thesis proposes a method to simulate the dynamics of an autonomous underwater vehicle towing another autonomous underwater vehicle of equivalent size using a marine cable in the vertical and horizontal plane. There is a coupling effect between the two vehicles because the towed vehicle is of equivalent size. This means that the towed vehicle cannot be modeled as just a payload but rather, must incorporate the forces and moments experienced and acting on it. In this work, only AUVs with symmetrical hulls are considered, where the towing AUV is moving at a constant velocity with a set thrust while the towed AUV has no thrust. The rope system is another important component that needs to be modeled correctly because the rope material and type significantly impact the motion of the vehicles. The rope system in this study is modeled using a numerical approach called the lumped mass spring damper method which is easy to understand and computationally inexpensive. The rope model accounts for buoyancy differences in different ropes and permits cable flexibility. This thesis enables us to study the motion of multiple combinations of different ropes and axi-symmetric types of underwater vehicles with any fixed or movable fin configuration. / M.S. / This thesis studies the motion of an autonomous underwater vehicle towing another autonomous underwater vehicle which is a large as it is. The towed vehicle cannot be assumed to be just a mass attached to the towing vehicle. There is an interaction between the two vehicle. The towed vehicle places a force on the towed vehicle and the towed vehicle likewise places a force on the towing vehicle. This interaction needs to be modeled correctly to fully capture the impact of both vehicles and their appendages. Additionally, the rope system poses a huge impact on the two vehicle depending on what type of rope is selected. Multiple factors affect the performance of a rope such as the shape and the elasticity. Some ropes may also be denser due to their material type and are less buoyant than others. These factors are considered in the modeling of the overall system and allows us to study different combinations of ropes and symmetric hulled autonomous underwater vehicles.

This paper analyzes the use of Igor Stravinsky's ballet, Le Sacre de Printemps (The Rite of Spring) in shows that are in the Drum Corps International circuit since 2000. The paper is divided into five main sections that cover information about drum corps, The Rite and its music, corps that use The Rite as their show theme, corps that use The Rite as movement, and other uses of The Rite in shows. The Rite of Spring is a renowned piece of orchestral and ballet repertoire that has become increasingly popular in drum corps shows.

This thesis describes a method of modeling financial markets by utilizing concepts from mechanical vibration. The models developed represent multi-degree of freedom, mass-spring systems. The economic principles that drive the design are supply and demand, which act as springs, and shareholders, which act as masses. The primary assumption of this research is that events cannot be predicted but the responses to those events can be. In other words, economic stimuli create responses to a stock’s price that is predictable, repeatable and scientific. The approach to determining the behavior of various financial markets encompassed techniques such as Fast Fourier Transform and discretized wavelet analysis. The researched developed in three stages; first an appropriate model of causation in the stock market was established. Second, a model of steady state properties was determined. Third, experiments were conducted to determine the most effective model and to test its predictive capabilities on ten stocks. The experiments were evaluated based on the model’s hypothetical return on investment. The results showed a positive gain on capital for nine out of the ten stocks and supported the claim that stocks behave in accordance to the natural laws of vibration. As scientific approaches to modeling the stock market are beginning to develop, engineering principles are proving to be the most relevant and reliable means of financial market prediction.