Breadfuit is a strange thing. It's a starchy potato-like sustenance not particularly noteworthy by most accounts. But it's history is amazing, an epic journey. Relocated from the Samoan island of Upalu to Oahu, Hawaii in the 12th Century as well as transplanted from Tahiti, as an economical food source for slaves in the West Indies in 1780 the lowly breadfruit has been held in the hands of Fletcher Christian, Captain Bligh, James Cook, King Kamehameha and innumerous other nameless individuals including Matt Spahr. This fruit contains the weight of colonialism, capitalism, exploration and tropical fantasy under its skin. The collision of histories such as these and the identities of related participants are the focus of the following essay.

The research presented here provides a basis for understanding the hydrodynamics of surfboard fin geometries. While there have been select studies on fins there has been little correlation to the shape of the fin and its corresponding hydrodynamic performance. This research analyzes how changing the planform shape of a surfboard fin effects its performance and flow field. This was done by isolating the taper and sweep distribution of a baseline geometry and varying each parameter individually whilst maintaining a constant span and surface area. The baseline surfboard fin was used as a template in Matlab to generate a set of x and y coordinates that defined the outline of the fin shape. These coordinates were then altered by changing either the sweep or taper distribution and resulted in new, unique planform shapes. The new shapes were used to generate 3D models with the NACA 0006 foil as the cross-section hydrofoil. After the geometry was modeled, each fin was meshed and simulated in CFD for incidence angles ranging from 0o to 20o and a fin Reynolds Number of 3.51x105. When the sweep distribution was changed, there was a direct correlation to vortex formation off the leading edge. Increasing the sweep generated a stronger vortex that persisted for higher angles of attack and resulted in higher moments but increased drag. Changing the taper distribution was not as influential. The tapered fin set showed similar flow fields and body forces to each other. Making a fin more rectangular had slight decreases in drag but made the shape more prone to separation.

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" Three dimensional travel in immersive virtual environments (IVE) has been a difficult problem since the beginning of virtual reality (VR), basically due to the difficulty of designing an intuitive, efficient, and precise three degrees of freedom (DOF) interface which can map the user's finite local movements in the real world to a potentially infinite virtual space. Inspired by the Silver Surfer Sci-Fi movie and the popularity of the Nintendo Wii Balance Board interface, a surfboard interface appears to be a good solution to this problem. Based on this idea, I designed and developed a VR Silver Surfer system which allows a user to surf in the sky of an infinite virtual environment, using either an isometric balance board or an elastic tilt board. Although the balance board is the industrial standard of board interface, the tilt board seems to provide the user more intuitive, realistic and enjoyable experiences, without any sacrifice of efficiency or precision. To validate this hypothesis we designed and conducted a user study that compared the two board interfaces in three independent experiments that break the travel procedure into separate DOFs. The results showed that in all experiments, the tilt board was not only as efficient and precise as the balance board, but also more intuitive, realistic and fun. In addition, despite the popularity of the balance board in the game industry, most subjects in the study preferred the tilt board in general, and in fact complained that the balance board could have been the cause of possible motion sickness. "

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-04-04T12:22:08Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) BIOMIMÉTICA E ARTEFATOS PARA AMBIENTES AQUÁTICOS - Estratégia de leveza e resistencia inspiradas na estrutura celular do ~1.pdf: 9452656 bytes, checksum: 5fc75ab99d22907c133d82009ac24b3d (MD5) / Made available in DSpace on 2017-04-04T12:22:08Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) BIOMIMÉTICA E ARTEFATOS PARA AMBIENTES AQUÁTICOS - Estratégia de leveza e resistencia inspiradas na estrutura celular do ~1.pdf: 9452656 bytes, checksum: 5fc75ab99d22907c133d82009ac24b3d (MD5) Previous issue date: 2015-12-21 / A biomimética visa o estudo das estratégias da natureza, tendo-a como princípio e inspiração para solução de problemas de design e outras áreas. Esta pesquisa é uma abordagem alternativa para processos de geração de soluções no design de estruturas de pranchas de surf. Atualmente os materiais e processos produtivos destes artefatos ainda estão distantes dos aspectos ecológicos e de um ciclo de vida de produto sustentável. Existem algumas alternativas, onde as pranchas são fabricadas com materiais orgânicos, como por exemplo, o Agave, porém ainda com processos ultrapassados, contrários às estratégias da natureza, que atuam num optimum de economia de matéria e energia, dentro de um ciclo de vida sustentável bem definido. Com base na metodologia DesignLens (Biomimicry Institute 3.8), os ensinamentos da natureza aliados à tecnologia representam potencial de inovação em design e sustentabilidade. Quando processos de design paramétrico foram incorporados à fabricação digital, se permitiu atingir um nível de materialização muito próximo das estratégias da natureza. Verificou-se que a aplicação de tecnologias digitais tem grande relevância para o futuro das áreas de projeto, principalmente quando alinhadas aos princípios de sistemas biológicos. Esta pesquisa obteve parte da validação através da impressão 3D de uma secção de uma prancha de surf como exemplo de aplicação, dentre muitas alternativas para as estratégias do Agave em estruturas. / Biomimetics aims study of the strategies of nature, having it as a principle and inspiration for design and troubleshooting other áreas. This research is an alternative approach to the processes of generation of solutions in the surfboards design. Currently the materials and production processes of these artifacts are still distant from ecological aspects and a sustainable product life cycle. There are some alternatives, where the boards are made with organic materials, as for example, Agave, but with outdated processes, contrary to nature, strategies that work in an optimum of economy of matter and energy, within a sustainable life cycle. Based on the DesignLens methodology (Biomimicry Institute 3.8), the teachings of nature coupled with technology represent potential for innovation in design and sustainability. When parametric design processes have been incorporated into the digital fabrication, if allowed to reach a level of materialization very close of the strategies of nature. The application of digital technologies has great relevance to the future of the project areas, especially when aligned to the principles of biological systems. This research obtained part of the validation through the 3D printing of a section of a surfboard as an example of application, among many alternatives for the strategies of Agave in structures.

This has been a project with the aim to develop a product which will solve what I consider to be the biggest difficulty and problem in the sport of wave surfing. That is to get enough speed to be able to stand up on the board and surf without the wave passing you. Today this is done only by paddling with your arms and this project has developed a product that helps the surfer to generate enough speed. This it makes wave surfing easier, especially for beginners and people with less physical ability. Another benefit with the product is that it enhances safety due to the possibility to start surfing further from the shore where stones and swimmers can be present. At the moment of standing up and starting to surf the risk of falling and possibly colliding with obstacles is the highest. A functional prototype has been developed that does this in an effective way, both economically and function wise. A general plan for development and introduction to the market has been developed. / Detta projekt har haft som mål att utveckla en produkt som löser vad jag anser är den största svårigheten inom vågsurfing, vilket är att uppnå tillräckligt med fart för att kunna ställa sig upp och surfa utan att vågen passerar förbi. Det görs i dagsläget genom att paddla med händerna och detta projekt har utvecklat en produkt som hjälper surfaren att uppnå tillräcklig med fart. Den gör vågsurfing enklare, särskilt för nybörjare och personer med begränsade fysiska förutsättningar. En ytterligare fördel med produkten är att den ger ökad säkerhet tack vare att man kommer med vågorna längre ifrån stranden där det kan finnas stenar och badande människor. Vid just detta momentet, då man ställer sig upp på brädan, är risken för att falla och eventuellt kollidera med hinder som störst. En prototyp har utvecklats som gör detta på ett effektivt sätt, både funktionsmässigt och ekonomiskt. En övergripande plan för utveckling och lansering av produkten har tagits fram.

New technology in radar opens up new possibilities for cheap and easily integrated human body presence detection. In this work, we aim to make a proof of concept that replaces the "dead man’s grip" on an electric surfboard with a more convenient wireless system based on micro radars. To answer the research questions identified, an artifact was created. To guide the research process and ensure that rigorous methods are used for constructing and evaluating the artifact, this thesis employs the research paradigm Design Science Research. The result was that the radar signal is completely degraded without a radome when the radar is wet. With a radome, the signal strength is a third wet compared to dry. Therefore, a radome is required to protect the radar and its function from the elements. The need for blockage detection was also defined. Observing how the direct leakage signal deviates from its normal state can determine whether the sensor is being blocked. Several algorithms were developed and tuned to prove the concept. Coverage and detection speed was tested and optimized. Overall, the potential of micro radars to replace a dead man’s grip on a surfboard is very promising. / Ny radarteknik öppnar nya möjligheter för billig och lättintegrerad upptäckt av människokroppens närvaro. I det här arbetet vill vi göra ett konceptbevis som ersätter "dödmansgreppet" på en elektrisk surfbräda med ett bekvämare trådlöst system baserat på mikroradar. För att besvara de identifierade forskningsfrågorna skapades en artefakt. För att vägleda forskningsprocessen och se till att rigorösa metoder används för att konstruera och utvärdera artefakten används forskningsparadigmet Design Science Research i denna avhandling.  Resultatet var att radarsignalen försämras fullständigt utan radom när radarn är våt. Med en radome är signalstyrkan en tredjedel våt jämfört med torr. Därför krävs en radome för att skydda radarn och dess funktion från väder och vind. Behovet av blockaddetektering definierades också. Genom att observera hur den direkta läckagesignalen avviker från sitt normala tillstånd kan man avgöra om sensorn är blockerad. Flera algoritmer utvecklades och justerades för att bevisa konceptet. Täckning och detektionshastighet testades och optimerades. På det hela taget ser mikroradarns potential att ersätta dödmansgrepp på en surfbräda mycket lovande ut.