Cette thèse fait partie du projet beyond the sea® qui a pour but de développer la traction par cerf-volant à boudins gonflés (kite) comme système de propulsion auxiliaire des navires. Comme le kite est une structure souple, il est nécessaire de mettre en place une boucle d’interaction fluide-structure pour calculer la géométrie du kite en vol et ses performances aérodynamiques. Un modèle de Ligne Portante 3D Non-Linéaire a été développé pour pouvoir gérer ces ailes non planes, avec des angles de dièdre et de flèche qui varient le long de l’envergure, et également pour pouvoir prendre en compte la non-linéarité du coefficient de portance de la section aérodynamique. Le modèle a été vérifié par des simulations RANSE sur différentes géométries et donne des résultats satisfaisants pour des angles d’incidence et de dérapage variant jusqu’à 15°, avec des différences relatives de quelques pour cent pour l’estimation de la portance globale de l’aile. Les résultats locaux sont aussi correctement estimés, le modèle est capable d’estimer la position du minimum et du maximum de chargement local, selon l’envergure de l’aile, et cela même pour une aile en dérapage. En parallèle, un modèle structure a été développé. L’idée principale du modèle Kite as a Beam est de réduire le kite à un ensemble d’éléments poutre, chacun équivalent à une partie du kite composé d’une section du boudin d’attaque, de deux lattes gonflées et de la canopée correspondante. Le modèle Kite as a Beam a été comparé à un modèle éléments finis complet du kite sur des cas de déplacements élémentaires. Les résultats montrent certaines différences de comportement entre les deux modèles, avec notamment une surestimation de la raideur en torsion pour le modèle Kite as a Beam. Finalement, le modèle Kite as a Beam a été couplé avec la Ligne Portante 3D Non-Linéaire, puis comparé au modèle éléments finis, couplé également avec la Ligne Portante. La réduction du temps de calcul est réellement importante mais les résultats de la comparaison montrent la nécessité de calibrer le modèle Kite as a Beam pour pouvoir retrouver correctement les résultats du modèle éléments finis. / The present thesis is part of the beyond the sea® project which aims to develop tethered kite systems as auxiliary devices for ship propulsion. As a kite is a flexible structure, fluid-structure interaction has to be taken into account to calculate the flying shape and aerodynamic performances of the wing. A 3D Non-Linear Lifting Line model has been developed to deal with non-straight kite wings, with dihedral and sweep angles variable along the span and take into account the non-linearity of the section lift coefficient. The model has been checked with 3D RANSE simulations over various geometries and produces satisfactory results for range of incidence and sideslip up to 15°, with typical relative differences of few percent for the overall lift. The local results are also correctly estimated, the model is able to predict the position of the minimum and maximum loading along the span, even for a wing in sideslip. Simultaneously, a structure model has been developed. The core idea of the Kite as a Beam model is to approximate a Leading Edge Inflatable kite by an assembly of beam elements, equivalent each to a part of the kite composed of a portion of the inflatable leading edge, two inflatable battens and the corresponding canopy. The Kite as a Beam model has been compared to a complete kite Finite Element model over elementary comparison cases. The results show the behaviour differences of the two models, for example the torsion stiffness is globally overestimated by the Kite as a Beam model. Eventually, the Kite as a Beam model coupled with the 3D Non-Linear Lifting Line model is compared to the complete finite element model coupled with the 3D Non-Linear Lifting Line model. The gain in computation time is really significant but the results show the necessity of model calibration if the Kite as a Beam model should be used to predict the results of the complete finite element model.

The subject of the diploma thesis is the elaboration of the technological project of the multifunctional building DASS in Martin. It is a two-storey building that will serve for the needs of DASS company. The diploma thesis assesses the building as a whole and focuses on selected technological processes. The work consists of the technical report, study of the implementation of the main technological stages of the main building, technological regulations for monolithic reinforced concrete horizontal structures and for vegetation flat roof, design of main construction machines and mechanisms, design and assessment of lifting mechanism and control-test plans for structures from technological regulations. Furthermore, a time and financial plan is developed. Than staff balance and a schedule of selected technological processes of the main building is processed. At the same time a construction site project, a health and safety plan, a noise study and LEED 2009 CORE & SHELL are prepared for the construction of a multifunctional building. The work is further supplemented by a specialization focused on the analysis of the contribution of green roofs on energy efficiency of buildings.

No description available.

The involvement of youth in the sport of weightlifting and the use of weightlifting methods as part of training for youth sport performance appears to be increasing. Weightlifting for children and adolescents has been criticized in some circles and is a controversial aspect of resistance training for young people. Although injuries can occur during weightlifting and related activities, the incidence and rate of injury appear to be relatively low and severe injury is uncommon. A number of performance, physical, and physiological variables, such as body composition, strength, and power, are improved by weightlifting training in children, adolescents, and young athletes. Manipulating program variables, when appropriate, can have a substantial and profound influence on the psychological, physiological, physical, and performance aspects of weightlifters. An understanding of the sport, scientific training principles, and musculoskeletal growth development is necessary to properly construct a reasonable and appropriate training program. A scientific background aids in providing an evidenced basis and sound rationale in selecting appropriate methods and directing adaptations toward more specific goals and enables the coach to make choices about training and competition that might not otherwise be possible. If weightlifting training and competition are age group appropriate and are properly supervised, the sport can be substantially safe and efficacious.

No description available.

No description available.

In the construction industry of today, many projects are getting bigger, higher and more complicated than ever before. The most important material in these projects is concrete and the process of casting has developed a lot during the last century. One specific casting procedure, the slipforming technique, is a well established method throughout the world and it is profitable when there are high demands on the aesthetics, the given time period is short, the structures are high and big or when a large number of standardized structures are to be cast. Slipforming is performed around the clock and due to the generally high work phase of today, slipforming is suitable because it can keep a steady phase without stopping. The material concrete is a subject that is constantly evolving and often new prescriptions, grades and types appear on the market. Experiments about for example alternative binders and different recipes have resulted in concrete being more flexible now than ever before. In general, one cannot find much information about how the concrete mix specifically should be when slipforming. Therefore, there is a need for investigating this further. This master thesis examines important properties and features that a concrete mix should possess to be suitable for slipforming. The choice of material composition and other affecting parameters are put forward to get a clear picture of how to accomplish an eminent slipform process. The study includes thorough investigations regarding both concrete and slipforms which formed an adequate foundation for the further research. Also, an examination on literature of how the two components work together, i.e. how the concrete behaves in a slipform, was carried out to the greatest possible extent. As expected, there was not much information written down about this subject which supported the alleged gap in the current literature. Subsequently, to obtain a deeper understanding of the matter, fifteen interviews were performed. The interviews formed a qualitative research process and the interviewees were consultants specialized in slipforming, project contractors and employees at concrete manufacturers. From the results, it can be concluded that there is no specific concrete mix advocated for slipforming. Important parameters such as stickiness, workability and hardening procedure are key aspects that need to be considered to create an adequate concrete mix. The basic things to keep in mind are that the amount of fine material should be small to avoid a sticky concrete, if crushed gravel is used it should be washed, the alternative binder should be adapted to the CEM I and the recommended alternative binders are PFA and GGBS. Further, the concrete mix is dependent on various other parameters that can be difficult to predict, such as weather and temperature at site, transport distance to site from the concrete factory and how well the site can keep a constant workflow around the clock. Accordingly, there is no standard recipe that is guaranteed to work in every project, but the most appropriate method is to perform tests on the possible mixes to be able to foresee how they will behave in the slipform. / Idag är byggprojekten större, högre och mer komplicerade än någonsin tidigare. Det viktigaste materialet i dessa projekt är betong och själva gjutningsprocessen har utvecklats väldigt mycket under det senaste århundradet. Glidformsgjutning är en väletablerad metod över hela världen och den är lönsam att använda när det ställs höga krav på estetiken, den angivna tidsperioden är kort, konstruktionerna är höga och stora eller när ett stort antal standardiserade konstruktioner ska gjutas. Glidformsgjutning utförs dygnet runt och på grund av den idag generellt höga arbetstakten är glidformsgjutning lämplig eftersom den kan hålla ett stadigt tempo utan att arbetet behöver stanna upp. Betong är ett material som ständigt utvecklas och det är inte sällan som det dyker upp nya recept, kvaliteter och typer på marknaden. Experiment med exempelvis alternativa bindemedel och olika recept har resulterat i att betongen nu är mer flexibel än någonsin tidigare. Generellt finns inte mycket nedskriven information om hur en betongblandning som specifikt lämpar sig för glidformsgjutning ska vara, därför finns det ett behov av att undersöka och sammanställa detta. Detta examensarbete utreder viktiga variabler, egenskaper och funktioner som en betongblandning bör ha för att lämpa sig för glidformsgjutning. Materialkomposition och andra parametrar som påverkar tas fram för att få en tydlig bild av hur man bäst åstadkommer en lyckad glidformsprocess. Studien omfattar en grundlig undersökning av både betong och glidformar som senare kom att verka som en grund för den vidare utredningen. Därtill genomfördes en litteraturstudie om hur de två komponenterna fungerar tillsammans, dvs. hur betongen beter sig i en glidform. Som förväntat fanns det inte mycket information om detta ämne vilket styrker det påstådda glappet i litteraturen. Därefter genomfördes 15 intervjuer med sakkunniga personer i branschen för att få en djupare förståelse av ämnet. Dessa intervjuer la grunden till den kvalitativa forskningsprocess som genomförts och de intervjuvade personerna var konsulter specialiserade på glidformsgjutning, projektentrepenörer och anställda hos betongtillverkare. Av resultatet att döma kan en slutsats dras om att det inte finns en enda, specifik betongblandning som lämpar sig för glidformsgjutning. Viktiga parametrar som klibbighet, arbetbarhet och härdningstid är nyckelaspekter som sätter grunden för att en lämplig betongmix kan tas fram. De grundläggande delarna att ha med sig är att mängden finmaterial ska vara liten för att undvika en klibbig betong, om krossgrus används ska det tvättas, det alternativa bindemedlet ska anpassas till cementet och de rekommenderade alternativa bindemedlen är masugnsslagg och flygaska. Vidare beror betongmixen också av ytterligare parametrar som kan vara svåra att förutse, som exempelvis väder och temperatur, transportsträcka till arbetsplatsen från betongfabriken samt huruvida arbetsplatsen kan hålla öppet dygnet runt eller inte. Således finns inget standardrecept som garanterat fungerar till samtliga projekt, utan det är lämpligast att göra tester för att kunna förutse hur betongmixen kommer att agera i glidformen och på så sätt prova sig fram.

Low back pain (LBP) remains the most prevalent and costly work-related disability worldwide and is directly associated with "physical" risk factors prevalent in manual material handling (MMH) tasks. Back-support exoskeletons (BSEs) are a promising ergonomic intervention to mitigate LBP risk, by reducing muscular exertion and spine loading. The purpose of this work was to help better understand both the "intended" and "unintended" consequences of BSE use on physical risk factors for LBP, as an essential prerequisite for the safe and effective implementation of this technology in actual workplaces. The first study assessed the effects of using two BSEs on objective and subjective responses during repetitive lifting involving symmetric and asymmetric postures. Wearing both BSEs significantly reduced peak levels of trunk extensor muscle activity and reduced energy expenditure. Such reductions, though, were more pronounced in the symmetric conditions and differed between the two BSEs tested. The second study quantified the assistive torque profiles of two passive BSEs using a computerized dynamometer, with both human subjects and a mannequin. Clear differences in torque magnitudes were evident between the BSEs, though both generated more assistive torques during flexion than extension. The third study estimated the effects of BSE use on lumbosacral compressive and shear forces during repetitive lifting using an optimization-based model. Using both BSEs reduced peak compression and anteroposterior shear forces, but these effects differed between tasks and BSE designs. Reductions in composite measures of trunk muscle activity did not correspond consistently with changes in spine forces when using a BSE. The fourth study quantified the effects of two passive BSEs on trunk stability and movement coordination during repetitive lifting. Some adverse effects on stability were evident for pelvis and thorax movements and coupling of these body segments, suggesting that caution is needed in selecting a BSE for a given MMH task. Overall, we found that the efficacy of BSEs is design- and task-specific. Important safety features of the exoskeletons were also identified, providing insights on their performance boundaries. Overall, the BSEs tested were more effective and safer in tasks closer to the mid-sagittal plane and with moderate degrees of trunk flexion. / Doctor of Philosophy / Low back pain (LBP) remains the most prevalent and costly work-related disability worldwide, and the risk of LBP is related to "physical" risk factors common in manual material handling (MMH) tasks. Back-support exoskeletons (BSEs) are a new ergonomic intervention that may reduce the risk of occupational LBP, by reducing muscular efforts and loads on the spine. For the safe use of BSEs, though, it is critical to better understand both the "intended" and "unintended" consequences of this emerging technology. In this dissertation, such consequences of BSE use were evaluated in the context of repetitive lifting tasks. The first study assessed the efficacy of two BSEs in terms of physical demands during repetitive lifting tasks involving a range of torso bending and twisting. Wearing both BSEs reduced the physical demands on back muscles and decreased energy consumption. Larger reductions, though, were observed in forward bending and such reductions differed between the two BSEs tested. The second study measured the amount of support provided by two BSEs using a new measurement method, which was examined for both human subjects and a mannequin. Clear differences in the BSE support were evident between the BSEs, and both devices generated more support during torso forward bending than returning upright. The third study estimated the effects of BSE use on low back loadings during repetitive lifting using a computational model. Using both BSEs reduced loads on the low back region, though such reductions were task-specific and depended on the BSE design. The fourth study quantified the effects of the BSE use on torso stability and movement patterns during repetitive lifting. Some adverse effects on stability were evident for lower and upper torso, suggesting that caution is needed in selecting a BSE for a given MMH task. Findings from this work show the potential benefits of BSEs for use in MMH tasks, yet such benefits can depend on the BSE design and the MMH task they are used for. Further, BSE use can lead to adverse effects, especially with tasks involving extreme working postures.

The human body has substantial kinetic and kinematic degrees-of-freedoms, so redundant solutions are available for the central nervous system (CNS) to perform a repetitive task. Due to these redundancies, inherent variations exist in human movement, called motor variability (MV). Current evidence suggests that MV can be beneficial, and that there is an inverse association between MV and risk of injury. To better understand how the CNS manipulates MV to reduce injury risks, we investigated the effects of individual differences, task-relevant aspects, and psychological factors as modifiers of MV. Earlier work found that experienced workers adapted more stable movements than novices in repetitive lifting tasks. To expand on this, we quantified how MV differs between experienced workers and novices in different lifting conditions (i.e., lifting asymmetry and fatigue). Three different measures (cycle-to-cycle SD, sample entropy, and the goal equivalent manifold) were used to quantify MV. In a symmetric lifting task, experienced workers had more constrained movement than novices, and experienced workers exhibited more consistent behavior in the asymmetric condition. Novices constrained their movements, and could not maintain the same level of variability in the asymmetric condition. We concluded that experienced workers adapt stable or flexible strategies depending on task difficulty. In a prolonged lifting task, both groups increased their MV to adapt to fatigue; they particularly increased variability in a direction that had no effects on their main task goal. Developing fatigue also makes it difficult for individuals maintain the main goal. Based on these results, we conclude that increasing variability is an adaptive strategy in response to fatigue. We also assessed variability in gait parameters to compare gait adaptability using a head-worn display (HWD) compared with head-down displays for visual information presentation. An effective strategy we observed for performing a cognitive task successfully during walking was to increase gait variability in the goal direction. In addition, we found that head-up walking had smaller effects on MV, suggesting that HWDs are a promising technology to reduce adverse events during gait (e.g., falls). In summary, these results suggest that MV can be a useful indicator for evaluating some occupational injury risks. / Ph. D.

Recovering 3D human motion from monocular video sequences poses a significant challenge in computer vision, particularly when the camera itself is in motion. The ambiguity introduced by dynamic recording setups necessitates methods to lift camera-local 3D human motions into a consistent, global world frame. This thesis proposes a novel, modular approach to monocular multi-person motion capture, combining regression techniques and global optimization for enhanced accuracy. Our pipeline for 3D motion recovery begins with image-based detection to localize multiple human subjects within each frame. We then fit parametric human body models (SMPL) to estimate the subjects’ 3D poses, resulting in camera-local human pose tracks. To recover camera motion, we implement a visual odometry (VO) algorithm. Next, we port a state-of-the-art global motion regression network to initially lift camera-local motions into a fixed world frame. Finally, we apply a global optimization process guided by re-projection quality, motion realism, and motion smoothness to refine the lifted motion estimates within the global 3D world frame. The core contribution of this thesis is the demonstration of the effectiveness of combining global motion regression with optimization in a chained manner. Ablation studies confirm that this hybrid approach yields superior results compared to the isolated use of either regression or optimization techniques. Our experimental results show that the proposed method achieves performance closely aligned with the state-of-the-art in SMPL-based human motion recovery. / Att återställa mänskliga 3D-rörelser från monokulära videosekvenser utgör en betydande utmaning i datorseende, särskilt när själva kameran är i rörelse. Den tvetydighet som introduceras av dynamiska inspelningsinställningar kräver metoder för att lyfta kameralokala 3D-mänskliga rörelser till en konsekvent global världsram. Denna avhandling föreslår ett nytt, modulärt tillvägagångssätt för monokulär multi-person motion capture, som kombinerar regressionstekniker och global optimering för ökad noggrannhet. Vår pipeline för 3D-rörelseåterställning börjar med bildbaserad detektering för att lokalisera flera mänskliga motiv inom varje bildruta. Vi anpassar sedan parametriska mänskliga kroppsmodeller (SMPL) för att uppskatta motivens 3D-poser, vilket resulterar i kameralokala mänskliga poseringsspår. För att återställa kamerarörelser implementerar vi en visuell odometri (VO) algoritm. Därefter portar vi ett toppmodernt globalt rörelseregressionnätverk för att initialt lyfta kameralokala rörelser till en fast världsram. Slutligen tillämpar vi en global optimeringsprocess som styrs av omprojektionskvalitet, rörelserealism och rörelsejämnhet för att förfina de lyfta rörelseuppskattningarna inom den globala 3D-världsramen. Kärnbidraget i denna avhandling är demonstrationen av effektiviteten av att kombinera global rörelseregression med optimering på ett kedjat sätt. Ablationsstudier bekräftar att denna hybridmetod ger överlägsna resultat jämfört med den isolerade användningen av antingen regression eller optimeringsteknik. Våra experimentella resultat visar att den föreslagna metoden uppnår prestanda som är nära anpassade till det senaste inom SMPL-baserad mänsklig rörelseåterhämtning.