In this study, the aim has been to investigate how different educational materials in the nature science subjects are designed with the intention of how many and what types of laboratory activities the pupils will encounter to contextualize the abstract nature of science to develop their understanding of the content and working methods of science. In order for the pupils to have the opportunity to develop a scientific understanding, it is necessary that they have the opportunity to use their senses to interpret the text that is presented to them. Through various sensual, experimental, and practical activities, pupils can gain an understanding of the abstract phenomena, concepts, and explanatory models of natural science. In today's schools, there are many teachers who use educational materials as their point of departure when teaching science. Educational materials have an important role in science teaching, but depending on how the educational materials are designed, they provide different conditions for learning. In this study, the number of laboratory activities, that appear in different educational materials for science teaching, is investigated, as well as whether these laboratory activities are designed in terms of their degree of freedom and openness. The following questions have been addressed in order to achieve the purpose of the study: - How many laboratory activities can be found in the various educational materials?-  Are there more laboratory activities in any of the three nature-oriented subjects, biology, physics, or chemistry? - What types of laboratory activities do the pupils encounter in the educational materials and what degree of openness and freedom do they include? The investigation has been carried out through a qualitative and quantitative text and content analysis where various educational materials have been analyzed based on the context-based learning (CBL) theory and the theory of laboratory classification. The results of the qualitative and quantitative text and content analysis showed that certain educational materials give the pupils more opportunities to connect the scientific content to real experiences. The results also showed that some educational materials have a greater variety of different laboratory forms where the pupils have the opportunity to develop an understanding of the different working methods and content of the natural sciences. The conclusion that can be drawn after this study is therefore that it is important that teachers carefully review the various2educational materials to gain insight into their design. Through insight into the design of the educational materials, the teacher can then supplement the educational materials with, for example, laboratories of varying degrees of openness and freedom to give the pupils the opportunity to fulfill the goals in the curriculum.

O Tiro com Arco é uma modalidade olímpica na qual os atletas exibem diversas estratégias de coordenação muscular na preparação do disparo da flecha, principalmente no período da liberação do clicker, tornando dificultosa a interpretação da coordenação de arqueiros no que tange à sua pontuação. Deste modo, algumas técnicas, como a Análise de Vetor Codificado e co-ativação/inibição recíproca, provenientes de abordagens de Controle Motor, podem ajudar-nos a desvendar quais parâmetros em comum que estes arqueiros utilizam quando atiram e sua relação com seu desempenho obtido durante o disparo sequencial de flechas. O objetivo do trabalho foi o de avaliar a coordenação muscular utilizada por arqueiros da seleção brasileira durante uma simulação qualificatória olímpica, através da técnica eletromiográfica. Participaram 11 arqueiros da seleção brasileira; idade: 25,2±4,9 anos, altura: 1,72±0,12m, peso: 68,6±11,8 kg, FITA score: 1258±43 pontos, Qualificação: 632±20 pontos, Flecha média: 8,7±0,3 pontos. A análise EMG foi dividida em 0,5s antes e 0,15s após a liberação do clicker. Foi utilizado o valor RMS deste sinal de doze músculos: no lado que traciona a corda (dominante) - FSD (Flexor Superficial dos dedos); ED (Extensor dos dedos); BBL (Bíceps Braquial); TBL (Tríceps Braquial Cabeça longa); GD (Grande Dorsal) PMC (Peitoral Maior Clavicular); TS (Trapézio Superior); SAD (Serrátil Anterior); RA (Reto Abdominal) e ML (Multífido Lombar). Lado não dominante (nD) DPnD (Deltóide Posterior); SAnD (Serrátil Anterior), no qual foram criados em 14 pares de análise (agonista-antagonista: FSD-ED; BBL-TBL; GD-PMC; TS-SAD; RA-ML; distal-proximal: FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; e mistos: PMC-SAD; GD-TS; SAD-SAnD; SAnD-DPnD; GD-DPnD), para a análise dentro das técnicas de Co-ativação/Inibição Reciproca e Análise de Vetor Codificado. Nos resultados; oito pares (FSD-ED; BBL-TBL; TS-SAD; FSD-BBL; FSD-TBL; ED-TBL; SAD-SAnD; SAnD-DPnD) co-ativaram diferentemente na transição de blocos (p<0.05); e 12 (FSD-ED; BBL-TBL; GD-PMC; TS-SAD; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; PMC-SAD; SAD-SAnD; SAnD-DPnD; GD-DPnD) co-ativaram diferentemente na comparação do escore obtido (p<0.05). Em nove pares, os arqueiros, evidenciaram diferentes estratégias de inibição recíproca na transição de blocos (FSD-ED; BBL-TBL; TS-SAD; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; SAD-SAnD; SAnD-DPnD) (p<0.05); um (TS-SAD) na análise de flechas (p<0.05); e nove (FSD-ED; BBL-TBL; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; SAD-SAnD; SAnD-DPnD; GD-DPnD) na análise do escore. A análise de Vetor Codificado apresentou que, no total de flechas disparadas nove pares (FSD-ED; GD-PMC; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; PMC-SAD; SAD-SAnD; SAnD-DPnD) mudaram a moda de fase de coordenação na transição de ajustes posturais, enquanto no desempenho 11 pares (FSD-ED; BBL-TBL; GD-PMC; TS-SAD; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; PMC-SAD; SAD-SAnD; SAnD-DPnD) evidenciaram tais mudanças. As técnicas apresentadas no presente estudo revelaram parâmetros em comum associados com as sequências temporais de disparo de flechas e com os escores obtidos por arqueiros de elite, isto corrobora com a complexidade da análise do desempenho em atletas de alto rendimento, contudo também colocam a disposição técnicas que ajudam na filtragem e verificação desses parâmetros outrora divergentes / Archery is an Olympic sport in which the athletes exhibit several muscular coordination patterns in the arrow shooting, mainly in the clicker falls tempo, making difficult the interpretation of the coordination of archers in what concerns to their score. Thus, some techniques, such as Vector Coding and co-activation/reciprocal inhibition, from Motor Control approaches, can help us to discover what common patterns these archers use when firing and their relation to their obtained performance during the sequential firing of arrows. Aim: evaluate the muscular coordination used by archers of the Brazilian team during an Olympic qualifying simulation, using the electromyographic technique. Eleven archers of the Brazilian team participated; age: 25.2 ± 4.9 years, height: 1.72 ± 0.12m, weight: 68.6 ± 11.8 kg, FITA score: 1258 ± 43 points, Qualification: 632 ± 20 points, Mean arrow: 8.7 ± 0.3 points. The EMG analysis was divided in 0.5s before and 0.15s after the release of the clicker. The RMS value of this twelve-muscle signal was used: drawning arm (dominant side) - FDS (Flexor Digitorum Superficilis); ED (Extensor Digitorum); BB (Biceps Brachii); TBL (Triceps Brachii - Long Head); LD (Latissimus Dorsi) PMC (Pectoralis Major Clavicular Head); UT (Upper Trapezius); ASD (Anterior Serratus); RA (Rectus Abdominis) and LM (Lumbar Multifidus). Non-dominant side (nD) DPnD (Posterior deltoid) and ASnD (Anterior Serratus non-dominant side); pairs created (Agonist-Antagonist: FDS-ED, BBL-TBL, LD-PMC, UT-ASD, RA-LM; Distal-Proximal: FDS-BBL, FDS-TBL, ED-BBL, ED-TBL and the pairs glenohumeral-scapular: PMC-SAD, GD-TS, SAD-SAnD, SAnD-DPnD, GD-DPnD) for analysis of co-activation/reciprocal inhibition and Vector Coding. Results; eight pairs (FDS-ED, BB-TBL, UT-ASD, FDS-BB, FDS-TBL, ED-TBL, ASD-ASnD, ASnD-DPnD) coactivated differently in blocks transition (p<0.05); and 12 (FDS-ED, BB-TBL, LD-PMC, UT-ASD, FDS-BB, FDS-TBL, ED-BB, ED-TBL, PMC-ASD, ASD-ASnD, ASnD-DPnD, LD-DPnD) co-activated differently in the score comparison (p<0.05). Also, the archers displayed different strategies of reciprocal inhibition in the blocks transition (FDS-ED, BB-TBL, UT-ASD, FDS-BB, FDS-TBL, ED-BBL, ED-TBL, ASD-ASnD; ASnD-DPnD) (p<0.05); one (UT-ASD) in the arrow analysis (p<0.05); and nine (FDS-ED, BB-TBL, FDS-BBL, FDS-TBL, ED-BBL, ED-TBL, ASD-ASnD, ASnD-DPnD, LD-DPnD) in the score analysis. Nine Vector Coding pairs (FDS-BB, FDS-TBL, ED-BB, ED-TBL, PMC-ASD, ASD-ASnD, ASnD- DPnD) changed the coordination phase mode in postural adjustments transition, while 11 pairs (FDS-ED; BB-TBL; LD-PMC; UT-ASD; FDS-BB; FDS-TBL; ED-BB; ED-TBL, PMC-ASD, ASD-ASnD, ASnD-DPnD) showed such changes in score analysis. The techniques presented in the present study revealed common parameters associated with temporal shoot-out and scores obtained by elite archers, dispite the complexity of performance analysis in high-performance athletes

L’objectif de ce travail porte sur le développement d’un modèle d’interaction fluide-structure adapté à la dynamique des éoliennes de grandes tailles avec des pales flexibles qui se déforment de manière significative sous l’effet de la pression exercée par le vent. Le modèle développé est basé sur une approche efficace d’IFS partitionnée pour un fluide incompressible et non visqueux en interaction avec une structure flexible soumise a des grandes transformations. Il permet de fournir une meilleure estimation de la charge aérodynamique et de la réponse dynamique associée du système (pales, mat, attachements, câbles) avec un temps de calcul raisonnable et pour des simulations sur des longues périodes. Pour la modélisation structurale, un élément fini de type solide 3D est développé pour l’étude dynamique des pales d’éolienne soumises à des grands déplacements et des grandes rotations. Une amélioration du comportement en flexion est proposée par l’introduction des degrés de liberté en rotation et l’enrichissement du champ de déplacements afin de décrire plus précisément la flexibilité des pales. Cet élément solide est apte de capter des modes de hautes fréquences qui peuvent s’avérer néfastes pour la stabilité du calcul. Deux techniques sont donc proposées pour les contrôler : la régularisation de la matrice masse et le développement des schémas d’intégration robustes de conservation et de dissipation d’énergie. Les chargements aérodynamiques sont modélisés en utilisant la Panel Method. Il s’agit d’une méthode aux frontières, relativement rapide par rapport à la CFD mais suffisamment précise pour calculer la distribution de la pression exercée sur la pale. Les modèles fluide et structure interagissent via un algorithme de couplage partitionné itératif dans lequel des considérations particulières sont prises en compte dans le contexte des grandes transformations. Dans un effort visant à instaurer un indicateur de fatigue dans la méthodologie proposée, des câbles précontraints sont introduits reliant le mat de l’éolienne au support. Une nouvelle formulation complémentaire en termes de contraintes est ainsi développée pour l’analyse dynamique des câbles 3D en comportement élasto-visco-plastique. Chaque méthode proposée a été d’abord validée sur des cas tests pertinents. Par la suite, des simulations numériques d’éoliennes avec des pales flexibles sont effectuées en vue d’affiner la compréhension de leur comportement dynamique et l’intérêt que la flexibilité des pales peut apporter à leur fonctionnement. / In this work, a numerical model of fluid-structure interaction is developed for dynamic analysis of giant wind turbines with flexible blades that can deflect significantly under wind loading. The model is based on an efficient partitioned FSI approach for incompressible and inviscid flow interacting with a flexible structure undergoing large transformations. It seeks to provide the best estimate of true design aerodynamic load and the associated dynamic response of such system (blades, tower, attachments, cables). To model the structure, we developed a 3D solid element to analyze geometrically nonlinear statics and dynamics of wind turbine blades undergoing large displacements and rotations. The 3D solid bending behavior is improved by introducing rotational degrees of freedom and enriching the approximation of displacement field in order to describe the flexibility of the blades more accurately. This solid iscapable of representing high frequencies modes which should be taken under control. Thus, we proposed a regularized form of the mass matrix and robust time-stepping schemes based on energy conservation and dissipation. Aerodynamic loads are modeled by using the 3D Vortex Panel Method. Such boundary method is relatively fast to calculate pressure distribution compared to CFD and provides enough precision. The aerodynamic and structural parts interact with each other via a partitioned coupling scheme with iterative procedure where special considerations are taken into account for large overall motion. In an effort to introduce a fatigue indicator within the proposed framework, pre-stressed cables are added to the wind turbine, connecting the tower to the support and providing more stability. Therefore, a novel complementary force-based finite element formulation is constructed for dynamic analysis of elasto-viscoplastic cables. Each of theproposed methods is first validated with differents estexamples.Then,several numerical simulations of full-scale wind turbines are performed in order to better understand its dynamic behavior and to eventually optimize its operation.

Spacecraft missions such as spacecraft docking and formation flying require high precision relative position and attitude data. Although Global Positioining Systems can provide this capability near the earth, deep space missions require the use of alternative technologies. One such technology is the vision-based navigation (VISNAV) sensor system developed at Texas A&M University. VISNAV comprises an electro-optical sensor combined with light sources or beacons. This patented sensor has an analog detector in the focal plane with a rise time of a few microseconds. Accuracies better than one part in 2000 of the field of view have been obtained. This research presents a new approach involving simultaneous activation of beacons with frequency division multiplexing as part of the VISNAV sensor system. In addition, it discusses the synchronous demodulation process using digital heterodyning and decimating filter banks on a low-power fixed point DSP, which improves the accuracy of the sensor measurements and the reliability of the system. This research also presents an optimal and computationally efficient six-degree-of-freedom estimation algorithm using a new measurement model based on the attitude representation of Modified Rodrigues Parameters.

Spacecraft missions such as spacecraft docking and formation flying require high precision relative position and attitude data. Although Global Positioining Systems can provide this capability near the earth, deep space missions require the use of alternative technologies. One such technology is the vision-based navigation (VISNAV) sensor system developed at Texas A&M University. VISNAV comprises an electro-optical sensor combined with light sources or beacons. This patented sensor has an analog detector in the focal plane with a rise time of a few microseconds. Accuracies better than one part in 2000 of the field of view have been obtained. This research presents a new approach involving simultaneous activation of beacons with frequency division multiplexing as part of the VISNAV sensor system. In addition, it discusses the synchronous demodulation process using digital heterodyning and decimating filter banks on a low-power fixed point DSP, which improves the accuracy of the sensor measurements and the reliability of the system. This research also presents an optimal and computationally efficient six-degree-of-freedom estimation algorithm using a new measurement model based on the attitude representation of Modified Rodrigues Parameters.

At the beginning of this master’s thesis the definition of types of robots using parallel kinematics are presented, its possibilities of usage and current prototypes are described. The second chapter focuses on the proposal of robot construction and sizing electric and non-electric components of robot hardware. Derivation of direct and inverse transform mechanisms with creating flowcharts of their algorithms are stated in the two following chapters. The state machine controlled from user interface is then programmed based on these flowcharts. At the end of the work, cable-driven robot positioning accuracy is evaluated and platform workspace, together with motion and electric parameters, are measured.

Designing mechanical products in a competitive environment can present unique challenges, and designers constantly search for innovative ways to increase efficiency. One way to save space and reduce cost is to use ortho-planar compliant mechanisms which can be made from sheets of material, or lamina emergent mechanisms (LEMs). This thesis presents principles which can be used for designing LEMs. Pop-up paper mechanisms use topologies similar to LEMs, so it is advantageous to study their kinematics. This thesis outlines the use of planar and spherical kinematics to model commonly used pop-up paper mechanisms. A survey of common joint types is given, as well as an overview of common monolithic and layered mechanisms. In addition, it is shown that more complex mechanisms may be created by combining simple mechanisms in various ways. The principles presented are applied to the creation of new pop-up joints and mechanisms, which also may be used for lamina emergent mechanisms. Models of the paper mechanisms presented in Chapter 2 of the thesis are found in the appendix, and the reader is encouraged to print, cut out and assemble them. One challenge associated with spherical and spatial LEM design is creating joints with the desired motion characteristics, especially where complex spatial mechanism topologies are required. Hence, in addition to a study of paper mechanisms, some important considerations for designing joints for LEMs are presented. A technique commonly used in robotics, using serial chains of revolute and prismatic joints to approximate the motion of complex joints, is presented for use in LEMs. Important considerations such as linkage configuration and mechanism prototyping are also discussed. Another challenge in designing LEMs is creating multi-stable mechanisms with the ability to have coplanar links. A method is presented for offsetting the joint axes of a spatial compliant mechanism to introduce multi-stability. A new bistable spatial compliant linkage that uses that technique is introduced. In the interest of facilitating LEM design, the final chapter of this thesis presents a preliminary design method. While similar to traditional methods, this method includes considerations for translating the mechanism topology into a suitable configuration for use with planar layers of material.

[pt] Atualmente está bem difundido o uso de novas modelagens matemáticas para o estudo do comportamento de micro e nano sistemas mecânicos e eléctricos. O problema de escala é notável quando o tamanho das moléculas, partículas, grãos ou cristais de um sólido é relativamente considerável em relação ao comprimento do microdispositivo. Nesses casos a teoria clássica dos meios contínuos não descreve apropriadamente a solicitação estrutural e é necessária uma abordagem mais geral através de teorias generalizadas não-clássicas que contém a elasticidade clássica como um caso particular delas, onde os parâmetros constitutivos que representam às partículas são desprezíveis. Quando os efeitos microestruturais são importantes, o comportamento não responde como um material homogêneo se não como um material homogêneo. Cem anos atrás os irmãos Cosserat desenvolveram uma teoria de grãos rígidos imersos dentro de um macromeio elástico; posteriormente Toupin, Mindlin e outros pesquisadores na década de 60 formularam a chamada teoria gradiente de deformações, que recentemente é um objeto de muitas investigações analíticas e experimentais. Na década de oitenta, Aifantis e colaboradores conseguiram desenvolver uma teoria de gradiente de deformações simplificada, baseada em só uma constante elástica adicional não-clássica representativa da energia de deformação volumétrica para caracterizar satisfatoriamente os padrões dos fenômenos não-clássicos. Beskos e colaboradores estenderam o campo de aplicações da proposta inicial de Aifantis e fizeram as primeira implementações de elementos de contorno 2D e 3D para análises de elasticidade gradiente estática, no domínio da frequência e a mecânica da fratura. Desde o tempo de Toupin e Mindlin, procura-se estabelecer uma base variacional da teoria e uma formulação consistente das condições de contorno cinemáticas e de equilíbrio, o que parece ter tido êxito com os recentes trabalhos de Amanatidou e Aravas. Esta tese apresenta a formulação do método híbrido de elementos de contorno e finitos na elasticidade gradiente desenvolvida por Dumont e Huamán decompondo o potencial de Hellinger-Reissner em dois princípios de trabalhos virtuais: o primeiro em deslocamentos virtuais e o segundo em forças virtuais. Com esta finalidade é considerado além dos parâmetros clássicos, o trabalho realizado pelas tensões, deformações, forças e deslocamentos não-clássicos. É apresentado o desenvoltimento das soluções fundamentais singulares e polinomiais atráves das equações diferenciais de sexta ordem obtidas da equação de equilíbrio em termos de deslocamento na elasticidade gradiente. É apresentada também a aplicaçõ do método híbrido de contorno para problemas de tensão axial unidimensional e flexão bidimensional de vigas. Finalmente mostra-se a aplicação numérica do método em elementos finitos, é verificado o patch test de elementos finitos de diferentes ordem e mostra-se também análises de convergência. / [en] The use of new mathematical modeling in the study of micro and Nano electro mechanical systems is currently becoming widespread. The scaling problem is apparent when the length of molecules, particles or grains immersed in the material is relatively important compared with the whole micro device dimension. Under this approach the classical theories of mechanics cannot describe suitably the structural requirement and it is necessary a more general outlook through non classical generalized theories which enclose the classical elasticity as a particular case where the non-classical constitutive parameters are negligible. When the microstructural effects are important, the material does not respond as a homogeneous but as a non-homogeneous one. A hundred years ago Cosserat brothers formulated a new theory of rigid grains which were embedded in an elastic macro medium; later Toupin, Mindlin along others researchers in 1960s developed a gradient strain theory which has been recently the source of many analystics and experimental investigations. In 1980s Ainfantis et al could develop a simplified strain gradient theory with just one additional non classical elastic constant which represents the volumetric elastic strain energy and characterized successfully the whole non classical pattern phenomenon. Beskos et al extended the treatment proposed initially by Aifantis and developed the first numerical applications for 2D and 3D boundary element methods and solved static as dynamic and crack problems. Since the times of Toupin and Mindlin it is looking for to establish a variational theory with a consistent cinematic and equilibrium boundary conditions, which seemed to have had success in the recent works of Amanatiodou and Aravas. This work presents the formulation of the hybrid boundary and finite element methods under the strain gradient scope which were developed by Dumont and Huamán through the versatile decomposition of the Hellinger-Reissner potential in two work principles: the displacements virtual work and the forces virtual work; both principles contain the virtual work performed by the non-classical magnitudes. Following, it is presented the complete development of singular and polynominal fundamental solutions abtained through the sixth order strain gradient differential equilibrium equations in terms of displacements. Next it is shown an application of the method to unidimensional truss element and bidimensional beam. Finally, it is presented a numerical application to strain gradient finite element, it is checked the patch tests to different elements orders and it is also shown a series of convergence analysis.