Drones have become more common, and are commercially available for consumers. Small drones can be used for unauthorized information gathering, or to cause disruptions. This has created a need for safe, effective countermeasures against drones. In this thesis, a method for countermeasures against drone imaging is investigated. The method is based on aiming and focusing a laser beam toward the camera of the drone. The retroreflection from the target is used as a feedback signal. Risley prisms were used to aim the beam, and an electrowetting lens was used to control the focus. Control algorithms based on the method called Stochastic Parallel Gradient Descent (SPGD), line searching and the Kalman filter are presented and evaluated. An experimental setup was used to track a moving target and dazzle a camera, demonstrating the validity of the method. Additionally, a simulation environment was used to estimate the potential performance of the control algorithms in a realistic scenario, under ideal circumstances.

Este trabalho estuda a influência da utilização de resíduos de concreto (fração graúda ou miúda) nas características físicas e mecânicas de blocos de concreto estruturais, comparando-as com as características obtidas para blocos produzidos com agregados naturais. Foram utilizados resíduos obtidos de diferentes fontes oriundas de uma indústria de pré-moldados e pesquisados limites para a substituição dos agregados naturais por esses agregados reciclados. Inicialmente, foram realizados ensaios de caracterização dos agregados reciclados de concreto para avaliar o potencial de aplicação de cada um deles. Após serem selecionados os dois agregados mais apropriados para o estudo (resíduos de vigotas e blocos), foram produzidos corpos de prova com três traços em volume 1:20, 1:15 e 1:10, com substituições de 100% e 50% para agregados graúdos e de 33% para agregados miúdos. Quase todos esses traços e substituições foram utilizados para produzir blocos de concreto em uma indústria de pré-moldados, objetivando-se obter resistências à compressão de 4.5, 8.0 e 12.0 MPa. Os resultados obtidos para blocos com agregados reciclados foram então comparados com aqueles obtidos utilizando-se agregados naturais. Observou-se que, apesar de algumas propriedades apresentarem alterações, foram obtidos valores adequados para os parâmetros mais importantes, principalmente quanto à resistência à compressão e à absorção de água. Por fim, foram produzidos e ensaiados prismas com os blocos com agregados reciclados que apresentaram melhor desempenho, sendo avaliados a resistência à compressão e o módulo de deformação. Os resultados mostraram que os valores de eficiência prisma/bloco não foram significativamente alterados e os valores para os módulos de deformação resultaram próximos, tanto para blocos com agregados reciclados quanto para blocos com agregados naturais / This research deals with the influence of the use of recycled concrete aggregate (coarse and fine) for physical and mechanical characteristics of concrete blocks comparing them with those ones obtained from blocks produced with natural aggregates. Residues from different sources of a prefabricated concrete blocks factory were used and limits for substituting natural aggregates for recycled aggregate were tested. First, several characterization tests for different recycled concrete aggregates were carried out in order to evaluate their properties. Two of them were selected and test samples were produced considering three different mix proportions in volume: 1:20, 1:15 and 1:10, with replacements of 100% and 50% of coarse aggregates and 33% of fine aggregates. Almost all of these proportions were used for preparing concrete blocks with three classes of compression strength: 4.5, 8.0 and 12.5 MPa. Then the obtained results were compared with those ones obtained for blocks with natural aggregates. Despite the fact of the properties were not the same, the physical and mechanical characteristics could be considered adequate, mainly regarding compression and water absorption. Finally, some prisms with blocks of recycled aggregate were produced and tested evaluating the results for compression and deformation modulus. One could observe that the strength rate prism/block was not significantly modified and the deformation modulus were similar either considering blocks of recycled aggregate or blocks of natural aggregate

The main components of the vibration-based microgenerator incorporate vibratile structure, magnetic thin film, and coils. In this thesis work, bulk-micromachining technology and laser-micromachining technology were used to fabricate the vibratile structure of the microgenerator. And this is the beginning of the development of the microgenerator. Bulk-micromachining technology was widely used in micro-electromechanical system (MEMS). The most advantage of the technology is that it can be integrated with IC process in the future. And the roughness of the wafer is the key point of the etching process. In addition, 355nm UV Nd:YAG laser was also used to fabricate the vibratile structure. The period of fabricating prototype can be shortened by laser-micromachining. In laser-micromachining system, the dual-prism was used to change the direction of the laser beam by adjusting the initial phase of one of the prisms. When the laser beam moves relatively to workstation, the cutting process can be proceeded. By this system, the cutting linewidth is controllable. This technology has be used to fabricate the microstructure successfully, and the aspect ratio is up to 10, and the feature size is 50µm. Circular spiral spring structure was fabricated successfully, and it is to be the vibratile structure of the microgenerator. Finite element software ANSYS was used to simulate the dynamic characterization of the vibratile structure and the vibration testing experiment was carried out. The result shows that the experimental resonant frequency is very close to the simulative resonant frequency. So this vibratile structure can be used in microgenerator.

Volvo Car Corporation (VCC) uses Computational Fluid Dynamics (CFD) and wind tunnel during the aerodynamic development of new vehicles. In the past VCC main focus has been on the drag force correlation to the wind tunnel measurements but in recent years improved methods for lift force correlations has been highly wanted. Three objectives were considered in this study to improve the lift force correlation between the CFD simulations and wind tunnel measurements for geometrical configurations of the V60 and S60 models.Poor mesh resolution for the wall bounded flow existed for the VCC mesh method and therefore prisms layers were considered in this thesis to increase the mesh resolution inside the boundary layer.As slick tyres generally were used in the CFD simulations better geometrical correlation was wanted to be studied as it could improve the lift force correlation between CFD simulations and wind tunnel measurements. Therefore detailed tyres were considered in this study.As the coarsest surface mesh size was used for the underbody and the components inside the engine bay, where some of the highest flow velocities occurred, mesh refinements were investigated for engine bay and underbody in this study.The prisms layers improved the predicted behavior for the boundary layer as it captured the large velocity gradients more accurately. Due to this, the skin friction prediction was also improved. Different flow behavior around the front wheels and rear wake occurred due to earlier separation. The different flow field caused an improved correlation for the lift force but worsened correlation for the drag force due to increased pressure at the rear of the cars. However, the front lift force trend correlation for the considered configurations was improved with the prisms layer mesh method.The detailed tyres caused slight more disturbances for the underbody flow which caused more attached flow around the rear of the car hence lowered pressure. Earlier separation around the front wheels also occurred for the detailed tyre geometry as the disturbed flow around the wheels was increased. Slight improved correlation for the front and rear lift forces to the wind tunnel measurements could be seen with the detailed tyre compared to the slick tyre.The mesh refinements for the engine bay and underbody showed significant differences for the flow at the underbody which had significant impact on the flow at the rear wake for the V60 model. Minor differences could be seen for the aerodynamic forces for the baseline configuration for the V60 model while great differences occurred for the configurations affecting the underbody. Due to this significant improved correlation for the front and rear lift force trends were achieved for the underbody configurations with the refined engine bay and underbody mesh method.Conclusions could be drawn that the prisms layer caused earlier separation due to its increased mesh resolution for the wall bounded flow. However, finer mesh resolution was needed inside the boundary layer to ensure consistent separation behavior for both the considered models. Improved correlation for the front lift force could however be seen. The detailed tyre only had minor effects on the flow field and aerodynamic forces and therefore not so important to include for further studies. The refined engine bay and underbody caused significant improved lift force trend correlation to the wind tunnel measurements and should be considered for future studies. To improve the correlation between CFD simulations and wind tunnel measurements increased mesh resolution for the wall bounded flow should be considered to better capture the large velocity gradients close to the wall.

Made available in DSpace on 2014-06-11T19:24:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-03-18Bitstream added on 2014-06-13T18:52:37Z : No. of bitstreams: 1 mauricio_rm_me_ilha_prot.pdf: 7189412 bytes, checksum: 165c0a934d87bdea5e70b44e57f92b0a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O principal objetivo do trabalho foi desenvolver o estudo de ligações diretas entre paredes de blocos de concreto em escala real e reduzida 1A. Foram realizados ensaios de resistência à compressão axial e medidas as deformações em blocos, prismas e paredes nas duas escalas. Também foram montadas paredes em forma de H assentadas sobre bases de concreto armado. Estas foram construídas de 2 formas: na primeira, chamada de PRl, foram construídas 3 (três) unidades de modo que a parede central não possuísse apoio em sua base, com isso, todo o carregamento aplicado foi transferido para as abas. Na segunda forma, chamada PH2, foram montadas 3 (três) unidades, e ,nestas, a parede central ficou apoiada em sua base, dessa maneira, observou-se os efeitos de transferência de carga entre paredes, simulando uma estrutura real, onde geralmente todas as paredes da edificação são apoiadas em outras paredes ou em vigas baldrames. Na confecção dos corpos-de-prova, nas duas escalas em estudo, foi empregada uma argamassa industrializada usada comercialmente. O carregamento foi introduzido de forma centrada, e as deformações foram medidas através de relógios comparadores e de extensômetros elétricos. Para a análise dos resultados foram empregados testes estatísticos, validando estatisticamente as conclusões. Também foi empregada uma análise através de elementos finitos, simulando os ensaios experimentais realizados, comparando-se os resultados e readequando o modelo numérico. Os resultados obtidos permitiram uma avaliação da eficiência dos modelos numéricos empregados e os ajustes necessários nos mesmos, o entendimento da forma de transferência das ações verticais entre as paredes interligadas e as correlações entre as escalas estudadas. / The main objective ofthis research was to develop a study of direct bond (stretcher bond) connections between walls of concrete blocks in real and 1:4 small-scale. In order to know the mechanical properties, it was accomplished shear and axial strength tests where it was also measured the strain in blocks, prisms and walls for both scales. It was executed walls in the H form supported by reinforced concrete base. These walls were done in two different ways, the first was called PRI, (with 3 specimens) it had no support in its central wall base, thus forcing that alI the load imposed to it was transferred to the lateral walIs throughout the connections. The second kind, which was called PH2, with also 3 specimens, was entirely support in its base. This was done in order to observe the load transference effects among walls simulating conventional structures, where all the walls are support over other walls or foundation beams. The specimens in both scales were made using industrialized mortar commercially used. The load was centralized imposed and strains were measurements by electrical displacement gages and strain gages. Statistical tests were used in the result analysis, statistically validating the conclusions. A finite element analysis was also used attempting to simulate the accomplished experimental tests, being this analytical model compared to the experimental results and then, by retrofitting the numerical analysis approaching their results. The obtained results allowed: an evaluation of the efficiency of the numeric models employed and the necessity of retrofitting the analysis; the comprehension in the way of transference of the vertical actions between the interlinked walls; and the correlations among the studied scales.

Este trabalho estuda a influência da utilização de resíduos de concreto (fração graúda ou miúda) nas características físicas e mecânicas de blocos de concreto estruturais, comparando-as com as características obtidas para blocos produzidos com agregados naturais. Foram utilizados resíduos obtidos de diferentes fontes oriundas de uma indústria de pré-moldados e pesquisados limites para a substituição dos agregados naturais por esses agregados reciclados. Inicialmente, foram realizados ensaios de caracterização dos agregados reciclados de concreto para avaliar o potencial de aplicação de cada um deles. Após serem selecionados os dois agregados mais apropriados para o estudo (resíduos de vigotas e blocos), foram produzidos corpos de prova com três traços em volume 1:20, 1:15 e 1:10, com substituições de 100% e 50% para agregados graúdos e de 33% para agregados miúdos. Quase todos esses traços e substituições foram utilizados para produzir blocos de concreto em uma indústria de pré-moldados, objetivando-se obter resistências à compressão de 4.5, 8.0 e 12.0 MPa. Os resultados obtidos para blocos com agregados reciclados foram então comparados com aqueles obtidos utilizando-se agregados naturais. Observou-se que, apesar de algumas propriedades apresentarem alterações, foram obtidos valores adequados para os parâmetros mais importantes, principalmente quanto à resistência à compressão e à absorção de água. Por fim, foram produzidos e ensaiados prismas com os blocos com agregados reciclados que apresentaram melhor desempenho, sendo avaliados a resistência à compressão e o módulo de deformação. Os resultados mostraram que os valores de eficiência prisma/bloco não foram significativamente alterados e os valores para os módulos de deformação resultaram próximos, tanto para blocos com agregados reciclados quanto para blocos com agregados naturais / This research deals with the influence of the use of recycled concrete aggregate (coarse and fine) for physical and mechanical characteristics of concrete blocks comparing them with those ones obtained from blocks produced with natural aggregates. Residues from different sources of a prefabricated concrete blocks factory were used and limits for substituting natural aggregates for recycled aggregate were tested. First, several characterization tests for different recycled concrete aggregates were carried out in order to evaluate their properties. Two of them were selected and test samples were produced considering three different mix proportions in volume: 1:20, 1:15 and 1:10, with replacements of 100% and 50% of coarse aggregates and 33% of fine aggregates. Almost all of these proportions were used for preparing concrete blocks with three classes of compression strength: 4.5, 8.0 and 12.5 MPa. Then the obtained results were compared with those ones obtained for blocks with natural aggregates. Despite the fact of the properties were not the same, the physical and mechanical characteristics could be considered adequate, mainly regarding compression and water absorption. Finally, some prisms with blocks of recycled aggregate were produced and tested evaluating the results for compression and deformation modulus. One could observe that the strength rate prism/block was not significantly modified and the deformation modulus were similar either considering blocks of recycled aggregate or blocks of natural aggregate

Daylighting is the use of natural light to replace artificial light. In traditional rooms sunlight will only illuminate the area closest to the window due to the high solar angle. The rear of the room appears gloomy and occupants will use electric lighting even though there is sufficient daylight to illuminate the interior. The first section of this thesis reports on the application of micro-prisms to glazing. Such systems could improve the penetration of the light and reduce the energy bill. Fig 1: (Left): A traditional window. (Right) A window with the top third coated in microprisms. The aim of the work is to develop suitable structures than can be easily and cheaply mass produced using an industrial UV embossing process. Whenever possible the requirements of this process dictate the physical characteristics of the microstructures. The development process includes all the stages from design to full-scale testing of the prototypes in an office. Several different mechanical methods are used to produce prismatic arrays that conform to an initial design calculation. Each sample is evaluated in terms of its physical characteristics, its optical properties and finally its ability to improve illumination within a room. The latter aspect is determined, not only by measurement, but also the subjective assessment of occupants. The second micro-textured surface to be examined is the microlens. Three systems are investigated: - A controlled diffuser incorporating cylindrical lenses to improve the distribution of the daylight. - An afocal pair of lenses to improve the penetration of daylight through beam-steering. - An angular filter to exclude direct sunlight while admitting diffuse light. Most of the research is concerned with the third system. On sunny days windows can cause sufficient glare that occupants will pull the venetian blinds. Not only will this exclude the direct sunlight but also the diffuse daylight, cause darkening of the room and leading to the use of artificial light. The angular filter or 'solar shade' uses microlenses to image the direct sunlight which can then be blocked by circular obturations. The diffuse sunlight is not focused and therefore transmitted so the room is not darkened. The research is based on experimentation with small-scale systems and computer modelling to optimise the system. The results show potential improvements over new 'smart' windows although mechanical tolerances are high.

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The main objective of this bachelor thesis was to gain awareness of accuracy and precision in total station measurements. Experiments were designed, executed and analyzed.   The approach to the subject was to examine measurements made with various prism set-ups. Prisms are supposed to be directed to the total station with the front face in the line of sight. In the experiment the prisms were directed in various angles in order to measure in non-perfect measuring arrangement and the behavior of the precision and accuracy were noted.   The mean values and standard uncertainties were calculated from the material as well as RMS Error in the cases where reference values could be used as true values. The reference values for comparison were available due to the possibility to use a test field – a network of concrete pillars with well-defined coordinates.   To see whether the precision (the standard uncertainty) changed between a measurement sample made with correctly positioned prisms and a measurement sample towards the angled prisms, a statistical test method was used. (The test method is recommended in the international standard ISO 17123-1; Optics and optical instruments, Field procedures for testing geodetic and surveying instruments, Part 1: Theory).   The results from the experiments showed that there were larger standard uncertainties in the slope distance measurements towards extreme angled prisms than to correctly directed prisms. Surprisingly it was also larger standard uncertainty in vertical angle measurements toward correctly directed prisms than slightly angled prisms. The mean values of the horizontal angle measurement drifted sideways in the measurements made towards one extreme angle to the opposite extreme so that a total shift of around one centimeter was detected at short distances as well as up to 100 m distance.    When aiming in between the separate prisms of 360-degree targets the standard uncertainty were larger in horizontal angle measurements at a few occasions where it seemed like the autolock function had chosen two different prisms to lock on to, at separate occasions. The standard uncertainties were also larger in all vertical angle measurements when aiming in between the prisms.   The results showed clearly that even when the standard uncertainties of the measurements were of equal size, the mean values – when measuring in the different test positions – could vary substantially. / Huvudsyftet med detta kandidatarbete var att öka medvetenheten angående noggrannhet och precision i mätningar utförda av en totalstation. Ett antal experiment planerades, genomfördes och analyserades.   De områden som undersöktes i projektet var hur mätningarna påverkades av olika sätt att vinkla prismor mot totalstationen. Det rekommenderas att rikta ett prismas framsida mot totalstationens siktlinje. I experimentet vinklades prismorna i olika lägen för att mätningar skulle utföras i icke-perfekta förhållanden.   Medelvärden och standardosäkerheter beräknades ur mätdatan samt RMSE i de fall där det fanns referensvärden att jämföra med. Dessa referensvärden var tillgängliga tack vare möjligheten att få utnyttja ett testfält med betongpelare med kända koordinater.   För att utröna om precisionen (standardosäkerheten) ändrades mellan mätningar på korrekt inriktade prismor och de mätningar som gjordes mot vinklade prismor, utfördes ett statistiskt test. (Testmetoden rekommenderas i den internationella standarden ISO 17123-1, Optics and optical instruments - Field procedures for testing geodetic and surveying instruments - Part 1: Theory).   Resultaten av undersökningarna visade att där var större standardosäkerheter i mätningar av den lutande längden när prismorna var extremt vinklade än när de var korrekt orienterade. Standardosäkerheten var något överraskande också större med korrekt riktade prismor i vertikalvinkel-mätningarna med autolockfunktionen än om prismorna var något utåtvinklade. Medelvärdena på horisontalvinklarna drev sidleds i mätningar gjorda i en extrem vinkelposition till den motsatta extremen så att en total förflyttning på runt en centimeter konstaterades på korta avstånd likväl som på avstånd upp till 100 m.   Vid inriktning av siktet mot områdena mellan de separata prismorna i 360-gradsmålen så ökade standardosäkerheten i horisontalvinkel vid ett par positioner då det verkade som att autolockfunktionen valde båda prismorna på var sida, vid olika tillfällen. Standardosäkerheten var också större vid samtliga vertikalvinkelmätningar mot områdena mellan prismorna.   Resultaten visade tydligt att även om standardosäkerheterna i mätningarna var i samma storleks-ordning så kunde medelvärdena av mätstorheten mellan de olika testpositionerna variera substantiellt.