Palaeomagnetic study of a subaerial volcanic ridge (São Jorge Island, Azores) for the cobb mountain subhron, volcano flank instability and tectonomagmatic implications

We present a palaeomagnetic study on 38 lava flows and 20 dykes encompassing the past 1.3 Myr on S. Jorge Island (Azores ArchipelagoNorth Atlantic Ocean). The sections sampled in the southeastern and central/western parts of the island record reversed and normal polarities, respectively. They indicate a mean palaeomagnetic pole (81.3 degrees N, 160.7 degrees E, K= 33 and A95= 3.4 degrees) with a latitude shallower than that expected from Geocentric Axial Dipole assumption, suggesting an effect of non-dipolar components of the Earth magnetic field. Virtual Geomagnetic Poles of eight flows and two dykes closely follow the contemporaneous records of the Cobb Mountain Subchron (ODP/DSDP programs) and constrain the age transition from reversed to normal polarity at ca. 1.207 +/- 0.017 Ma. Volcano flank instabilities, probably related to dyke emplacement along an NNWSSE direction, led to southwestward tilting of the lava pile towards the sea. Two spatially and temporally distinct dyke systems have been recognized on the island. The eastern is dominated by NNWSSE trending dykes emplaced before the end of the Matuyama Chron, whereas in the central/western parts the eruptive fissures oriented WNWESE controlled the westward growth of the S. Jorge Island during the Brunhes Chron. Both directions are consistent with the present-day regional stress conditions deduced from plate kinematics and tectonomorphology and suggest the emplacement of dykes along pre-existing fractures. The distinct timing and location of each dyke system likely results from a slight shift of the magmatic source.

Agenesia do ligamento cruzado anterior – estudo de caso

A agenesia do ligamento cruzado anterior é uma condição extremamente rara. Dada a importância desta estrutura na função muscular, cinética e cinemática do joelho, especula-se que muitas serão as alterações decorrentes desta patologia . Perante o caso de uma atleta com agenesia do ligamento cruzado anterior, este trabalho pretendeu estudar os possíveis défices resultantes desta condição e, perceber se as alterações encontradas no membro com agenesia constituem uma estratégia de compensação eficaz, para um joelho com ausência do ligamento cruzado anterior. Desta forma , foi realizada uma avaliação da força dos músculos quadricípite e isquiotib iais , num dinamómet ro isocinético, a 60°/s e 180°/s. Fo i também recolhido o sinal electromiográfico do vasto medial, bicípite femural e gastrocnémio medial, durante a realização do salto vertical e horizontal. Os dados foram comparados bilateralmente. Os resultados evidenciaram um défice de força dos extensores do joelho com agenesia do LCA. No entanto, para os isqu iotibiais esse défice não foi evidente. A electromiografia não revelou uma estratégia de compensação consistente. Contudo, os resultados realçaram a importância dos flexores do joelho e plantares na estabilização dinâmica de um joelho com ausência do ligamento cruzado anterior. Concluiu-se que as alterações encontradas não formam uma adaptação eficiente .

A study on the modeling of sandwich functionally graded particulate composites

Dual-phase functionally graded materials are a particular type of composite materials whose properties are tailored to vary continuously, depending on its two constituent's composition distribution, and which use is increasing on the most diverse application fields. These materials are known to provide superior thermal and mechanical performances when compared to the traditional laminated composites, exactly because of this continuous properties variation characteristic, which enables among other advantages smoother stresses distribution profile. In this paper we study the influence of different homogenization schemes, namely the schemes due to Voigt, Hashin-Shtrikman and Mod-Tanaka, which can be used to obtain bounds estimates for the material properties of particulate composite structures. To achieve this goal we also use a set of finite element models based on higher order shear deformation theories and also on first order theory. From the studies carried out, on linear static analyses and on free vibration analyses, it is shown that the bounds estimates are as important as the deformation kinematics basis assumed to analyse these types of multifunctional structures. Concerning to the homogenization schemes studied, it is shown that Mori-Tanaka and Hashin-Shtrikman estimates lead to less conservative results when compared to Voigt rule of mixtures.

Complex dynamics in the trajectory control of redundant manipulators

Redundant manipulators allow the trajectory optimization, the obstacle avoidance, and the resolution of singularities. For this type of manipulators, the kinematic control algorithms adopt generalized inverse matrices that may lead to unpredictable responses. Motivated by these problems this paper studies the complexity revealed by the trajectory planning scheme when controlling redundant manipulators. The results reveal fundamental properties of the chaotic phenomena and give a deeper insight towards the development of superior trajectory control algorithms.

Trajectory planning of redundant manipulators using genetic algorithms

The trajectory planning of redundant robots is an important area of research and efficient optimization algorithms are needed. This paper presents a new technique that combines the closed-loop pseudoinverse method with genetic algorithms. The results are compared with a genetic algorithm that adopts the direct kinematics. In both cases the trajectory planning is formulated as an optimization problem with constraints.

Dynamic behaviour of soft core sandwich beam structures using kriging-based layerwise models

Sandwich structures with soft cores are widely used in applications where a high bending stiffness is required without compromising the global weight of the structure, as well as in situations where good thermal and damping properties are important parameters to observe. As equivalent single layer approaches are not the more adequate to describe realistically the kinematics and the stresses distributions as well as the dynamic behaviour of this type of sandwiches, where shear deformations and the extensibility of the core can be very significant, layerwise models may provide better solutions. Additionally and in connection with this multilayer approach, the selection of different shear deformation theories according to the nature of the material that constitutes the core and the outer skins can predict more accurately the sandwich behaviour. In the present work the authors consider the use of different shear deformation theories to formulate different layerwise models, implemented through kriging-based finite elements. The viscoelastic material behaviour, associated to the sandwich core, is modelled using the complex approach and the dynamic problem is solved in the frequency domain. The outer elastic layers considered in this work may also be made from different nanocomposites. The performance of the models developed is illustrated through a set of test cases. (C) 2015 Elsevier Ltd. All rights reserved.

On the requirements of interpolating polynomials for path motion constraints

In the framework of multibody dynamics, the path motion constraint enforces that a body follows a predefined curve being its rotations with respect to the curve moving frame also prescribed. The kinematic constraint formulation requires the evaluation of the fourth derivative of the curve with respect to its arc length. Regardless of the fact that higher order polynomials lead to unwanted curve oscillations, at least a fifth order polynomials is required to formulate this constraint. From the point of view of geometric control lower order polynomials are preferred. This work shows that for multibody dynamic formulations with dependent coordinates the use of cubic polynomials is possible, being the dynamic response similar to that obtained with higher order polynomials. The stabilization of the equations of motion, always required to control the constraint violations during long analysis periods due to the inherent numerical errors of the integration process, is enough to correct the error introduced by using a lower order polynomial interpolation and thus forfeiting the analytical requirement for higher order polynomials.

Modeling and Control of a Dragonfly-Like Robot

Dragonflies demonstrate unique and superior flight performances than most of the other insect species and birds. They are equipped with two pairs of independently controlled wings granting an unmatchable flying performance and robustness. In this paper it is studied the dynamics of a dragonfly-inspired robot. The system performance is analyzed in terms of time response and robustness. The development of computational simulation based on the dynamics of the robotic dragonfly allows the test of different control algorithms. We study different movement, the dynamics and the level of dexterity in wing motion of the dragonfly. The results are positive for the construction of flying platforms that effectively mimic the kinematics and dynamics of dragonflies and potentially exhibit superior flight performance than existing flying platforms.

Chaos Dynamics in the Trajectory Conjtrol of Redundant Manipulators

Nonlinear Dynamics, chaos, Control, and Their Applications to Engineering Sciences: Vol. 6 - Applications of nonlinear phenomena

Contributo para o desenvolvimento de uma metodologia que avalia a posição da omoplata: fidedignidade intra e interobservador e validade concorrente

RESUMO: Introdução: A relação cinemática entre as articulações do CAO apresenta grande importância na função do MS, e é por isso cada vez mais investigada e descrita. O posicionamento da omoplata ganha um importante papel para compreender as DCAO. É indiscutível o importante papel da omoplata na dinâmica do MS, bem como o posicionamento escapular como parâmetro clínico de disfunção do CAO. Todos estes factores criam a necessidade de desenvolver instrumentos de avaliação da posição da articulação ET. A grande maioria dos testes de avaliação, restringem a sua avaliação às disfunções da articulação GU, não integrando uma avaliação mais dinâmica e interactiva que respeite os pressupostos teóricos inerentes ao REU. È importante também que os métodos de avaliação sejam de fácil aplicabilidade clínica e que avaliem fidedignamente e com validade os outcomes. Objectivos: Contribuir para o desenvolvimento de uma metodologia de avaliação da omoplata em diferentes amplitudes do MS, através do estudo da validade concorrente, da fidedignidade intra e inter-observador. Metodologia: A amostra foi constituída por 20 elementos seleccionados por conveniência, entre o corpo de discentes da ESS-IPS, sem história de disfunção do CAO. Foi realizada uma análise cinemática ao MS de cada sujeito, usando um aparelho de análise por varrimento electromagnético, o FOB. Em cada sujeito foram ainda medidas, as distâncias escapulares em estudo, usando a fita métrica. Cada método de medição foi constituído por dois momento (teste e reteste), em cada momento, as medidas eram recolhidas por dois investigadores distintos. Resultados e Discussão: Foram considerados como positivos os resultados que se apresentassem acima do limiar de 0,5, que classifica uma correlação como moderada a excelente. Os resultados da validade mostram que para o investigador 1 nas medidas M1e M2 apenas houve correlação com valores excelentes a moderados até aos 30º de elevação do MS. Já para M3 apenas aos 30º no plano da omoplata essa mesma correlação não tem valores próximos do cutpoint. Em M4 nenhum valor tem correlação significativa com os valores do FOB, chegando mesmo a haver correlação negativa para os 120º no plano da omoplata. Em M5 apenas os 0º mostram valores correlacionais excelentes a moderados. Para o investigador 2, em M1 e M2 á semelhança do investigador 1, só existem valores de correlação significativos até aos 30º de elevação do MS. Já para M3 todos os valores mostram excelente a moderada correlação á excepção dos 120º no plano frontal. Em M4 este investigador apresenta maus resultados. Já em M5 os valores de correlação são moderados aos 0º e aos 90º. No que diz respeitos aos resultados dos CCI intra-observador,podemos afirmar que foi em M5 que estes valores mais se aproximaram do cut point. M1 e M2 são as medidas onde se encontram resultados menos satisfatórios. É aos 60º que existem valores mais satisfatórios, seguidos pelos 0º e 30º, quando nos aproximamos de graus mais elevados, como 90º e 120º, estes valores tendem a baixar. Quanto á fidedignidade inter-observador para M1 apenas aos 90º e aos 120º houve valores de correlação abaixo do cutpoint. Em M2, só os 60º do plano sagital não teve valores acima do cutpoint, em M3 apenas os 30º plano sagital não obtiveram valores acima do cut-point, o mesmo acontece para M3 aos 30º plano da omoplata e em M5 aos 30º e 120º no plano frontal. Conclusão: Os resultados deste estudo indicam que a metodologia em causa apresenta elevado grau de fidedignidade inter-observador, já no que toca é fidedignidade intra-observador o grau de semelhança não é tão elevado. Também o erro associado á medida não ultrapassou 1,5cm, sendo considerado baixo. Na validade concorrente concluímos que é aos 0º que a metodologia se torna uma opção válida na aferição das distâncias medidas com uma boa a excelente concordância com o FOB. As medidas consideradas como opções válidas, nas diferentes amplitudes, podem funcionar como parâmetros clínicos de caracterização do posicionamento da omoplata, podendo vir a contribuir ainda para a caracterização da orientação da mesma.-------------------- ABSTRACT:Introduction: The kinematic relationship between the joints of the CAO has great importance in the function of MS, which is why more and more investigated and described. The positioning of the blade gets an important role in understanding the DCAO. There is no doubt the important role of the scapula in the dynamics of MS as well as the positioning of scapular dysfunction as a clinical parameter of the CAO. All these factors create the need to develop tools for evaluating the place of articulation ET. Most assessment tests, restrict its assessment to GU joint disorders, not incorporating a more dynamic and interactive way that respects the theoretical assumptions inherent in the REU. It is also important that the methods are easy to apply clinical and reliably to assess the validity and outcomes. Objectives: To contribute to the development of a methodology for evaluating the scapula in different ranges of MS, through the study of concurrent validity, reliability of intra-and inter-observer. Methodology: The sample consisted of 20 selected elements for convenience, between the body of students of IPS-ESS with no history of dysfunction of the CAO. We performed a kinematic analysis of each subject to MS, using a scanning device for electromagnetic analysis, the FOB. In each subject were also measured, the scapular distances under study, using tape measure. Each method of measuring the time consisted of two (test and retest), in each moment, the measures were collected by two different investigators. Results and Discussion: We considered as positive results that were above the threshold of 0.5, which ranks as a moderate to excellent correlation. The results show that the validity for the researcher in an action M1e M2 was only correlated with moderate to excellent values up to 30º of elevation of the MS. As for M3 only to 30º in the plane of the scapula has the same correlation values near the cutpoint. M4 has no value in correlation with the values of the FOB, and even negative correlation to 120 ° in the plane of the scapula. In M5 show only the values 0 ° correlational excellent to moderate. For investigator 2 in M1 and M2 will be like an investigator, there are only significant correlation values up to 30º of elevation of the MS. As for M3 all the values show excellent correlation to moderate with the exception of 120 ° in the frontal plane. In this researcher M4 has bad results. M5 already in the correlation values are moderate to 0º and 90 º. Regarding the results of ICC intra-observer, we can say that M5 was that these values come closest to the cut point. M1 and M2 are measures which are less than satisfactory results. At 60 ° there are more satisfactory values, followed by 0º and 30º, when we approached the highest levels, such as 90 ° and 120 °, these values tend to decrease. The inter-observer reliability for M1 only to 90 º and 120 ºcorrelation values were below the cutpoint. In M2, only 60 of the sagital plane did not have values above the cutpoint in M3 only 30º sagital plane did not obtain values above the cut-point, the same goes for M3 at 30 ° plane of the scapula and M5 at 30 º and 120 º in frontal plane. Conclusion: The results of this study indicate that the methodology in question has a high degree of inter-observer reliability, as far as intra-observer reliability is the degree of similarity is not as high. Also the error of measure did not exceed 1.5 cm, and is considered low. In concurrent validity conclude that it is at 0 ° the methodology becomes a valid option for the measurement of distances measured with a good to excellent agreement with the FOB. The measures considered as valid options in different amplitudes, can function as clinical parameters to characterize the positioning of the shoulder blade and could further contribute to the characterization of the orientation of the same.

Avatar modeling: a telepresence study with natural user interface

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

Stromal vascular fraction cell sheets angiogenic potential for tissue engineering and regenerative medicine applications

One of the biggest concerns in the Tissue Engineering field is the correct vascularization of engineered constructs. Strategies involving the use of endothelial cells are promising but adequate cell sourcing and neo-vessels stability are enduring challenges. In this work, we propose the hypoxic pre-conditioning of the stromal vascular fraction (SVF) of human adipose tissue to obtain highly angiogenic cell sheets (CS). For that, SVF was isolated after enzymatic dissociation of adipose tissue and cultured until CS formation in normoxic (pO2=21%) and hypoxic (pO2=5%) conditions for 5 and 8 days, in basal medium. Immunocytochemistry against CD31 and CD146 revealed the presence of highly branched capillary-like structures, which were far more complex for hypoxia. ELISA quantification showed increased VEGF and TIMP-1 secretion in hypoxia for 8 days of culture. In a Matrigel assay, the formation of capillary-like structures by endothelial cells was more prominent when cultured in conditioned medium recovered from the cultures in hypoxia. The same conditioned medium increased the migration of adipose stromal cells in a scratch assay, when compared with the medium from normoxia. Histological analysis after implantation of 8 days normoxic- and hypoxic-conditioned SVF CS in a hindlimb ischemia murine model showed improved formation of neo-blood vessels. Furthermore, Laser Doppler results demonstrated that the blood perfusion of the injured limb after 30 days was enhanced for the hypoxic CS group. Overall, these results suggest that SVF CS created under hypoxia can be used as functional vascularization units for tissue engineering and regenerative medicine.

A case study of product usability of a pelvic device used by children with neuromotor impairments

On assistive technology targeted for people with activity limitations and participation, usability issues becomes an essential tool to ensure that the product has the appropriate ergonomics characteristics, in other words, ensure that it fits the specific user´s needs. The aim of this study was to analyze the usability of an adaptive seating device for children with neuromotor impairments, by using kinematic indicators of the reaching movement. The study sample consisted of 13 children with associated neurologic conditions. The tests were developed by using a wooden bench height adjustable, integrated with the adaptive seating device under study, and a system to capture three-dimensional image, called Qualisys Track Manager. The following reaching kinematics variables were measured: maximum reaching velocity, movement duration, index of curvature, and unit movements. It was found that the use of the adaptive seating device had a positive impact on upper limb function in children with neuromotor impairments. It was also noticed an improvement in the reaching movement kinematics, which was statistical significant for the index of curvature and unit movements. As main conclusions, it is possible to point out some positive effects that the product under study seems to have on users' movements, such as the improved movement quality of the upper limb, which could mean a better postural adjustments and higher trunk postural control. By identifying new measures of usability in terms of effectiveness and efficiency for the analyzeddevice, the results obtained may serve also as performance indicators, providing new data that may help to improve the product and eventually modifying it, in order to turn it more compatible with the needs of the considered target population.

Centrality and rapidity dependence of inclusive jet production in sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Measurements of the centrality and rapidity dependence of inclusive jet production in sNN−−−√=5.02 TeV proton--lead (p+Pb) collisions and the jet cross-section in s√=2.76 TeV proton--proton collisions are presented. These quantities are measured in datasets corresponding to an integrated luminosity of 27.8 nb−1 and 4.0 pb−1, respectively, recorded with the ATLAS detector at the Large Hadron Collider in 2013. The p+Pb collision centrality was characterised using the total transverse energy measured in the pseudorapidity interval −4.9<η<−3.2 in the direction of the lead beam. Results are presented for the double-differential per-collision yields as a function of jet rapidity and transverse momentum (pT) for minimum-bias and centrality-selected p+Pb collisions, and are compared to the jet rate from the geometric expectation. The total jet yield in minimum-bias events is slightly enhanced above the expectation in a pT-dependent manner but is consistent with the expectation within uncertainties. The ratios of jet spectra from different centrality selections show a strong modification of jet production at all pT at forward rapidities and for large pT at mid-rapidity, which manifests as a suppression of the jet yield in central events and an enhancement in peripheral events. These effects imply that the factorisation between hard and soft processes is violated at an unexpected level in proton--nucleus collisions. Furthermore, the modifications at forward rapidities are found to be a function of the total jet energy only, implying that the violations may have a simple dependence on the hard parton--parton kinematics.

Modelling Z→ττ processes in ATLAS with τ-embedded Z→μμ data

This paper describes the concept, technical realisation and validation of a largely data-driven method to model events with Z→ττ decays. In Z→μμ events selected from proton-proton collision data recorded at s√=8 TeV with the ATLAS experiment at the LHC in 2012, the Z decay muons are replaced by τ leptons from simulated Z→ττ decays at the level of reconstructed tracks and calorimeter cells. The τ lepton kinematics are derived from the kinematics of the original muons. Thus, only the well-understood decays of the Z boson and τ leptons as well as the detector response to the τ decay products are obtained from simulation. All other aspects of the event, such as the Z boson and jet kinematics as well as effects from multiple interactions, are given by the actual data. This so-called τ-embedding method is particularly relevant for Higgs boson searches and analyses in ττ final states, where Z→ττ decays constitute a large irreducible background that cannot be obtained directly from data control samples.