The master´s thesis concentrates on a project of steam turbine with controlled extraction points destined for a communal waste incineration plant. First, there the history of devices using steam as a moving medium is introduced and than follows the description of computing program, where the calculation was running. The master´s thesis subject consists in the thermodynamic project of turbine vaning, in basic project of gearbox including the check calculations and in technical economic comparison of single shaft and twin shaft constructional design. The design documentation is worked up according to the calculated outcomes and contains longitudinal section of turbine and dispositional turbine and gearbox settlement.

INTRODUCTION: The aim of this thesis is to identify the effect of trunk stabilization training based on Dynamic Neuromuscular Stabilization (DNS) on maximum kayak ergometer power output and reported self-disability in the shoulder girdle area. METHOD: Thirty flatwater kayakers of both genders (17 - 25 years old) were randomly divided into two groups. Crossover design was used for this study. Subjects in the experimental group (group A) integrated DNS exercises into standard flatwater training during the first phase. The control group (group B) conducted only common flat water training at the same time. After 6 weeks, the groups were switched. Then group B underwent the same DNS exercise with the same intensity and the same time. The intervention was the same for both phases and took 6 weeks. Group A performed only standard off-season training during the second phase. The maximum power output on kayak ergometer was measured three times (before study, after 6 weeks and after 12 weeks). Disabilities of the Arm, Shoulder and Hand (DASH) were analyzed at the same time. RESULTS: Initially, no significant differences in maximum power output on kayak ergometer and the DASH questionnaire score were identified between the groups. During the first phase the experimental group (group A) improved the maximum...

Virtual Power Plants (VPPs) are an emerging form of technology that allows owners of electricity producing appliances, such as electric vehicles, to partake in a pool of producers of sustainable energy. The Swedish electricity grid owner Svenska Kraftnät hosts a platform where VPPs act as intermediaries between energy producing customers and third party buyers. A requirement to participate in these transactions, however, is to post a bid specifying the amount of power that can be produced from a VPP during a given hour at least 48 hours into the future. This is where forecasting comes into the picture. This report compares the accuracy of eight different machine learning models when tasked with forecasting power output using the same training data from an electric vehicle-based VPP. The study also examines which inferences about customer behavior can be drawn from the same data and give strategic recommendations to VPPs based on the findings of the study. Upon evaluating the results, it was found that deep learning models outperformed autoregressive models, which in turn outperformed Random Forest Regression and Support Vector Regression. As for customer behaviors found in the data, a small negative correlation between spot prices and delivered output was found, suggesting that customers limit their charging when spot prices are high. Further, more power is generally produced during nighttime and on weekends. The data also shows an autocorrelation with a lag of 24 hours, suggesting that charging behaviors on a given day influence charging behaviors the subsequent day. / Virtuella kraftverk (VPPs) är en framväxande form av teknologi som tillåter ägare av elproducerande enheter, till exempel elbilar, att delta i ett nätverk av producenter av hållbar energi. Den svenska elnätsägaren Svenska Kraftnät driver en plattform där VPPs agerar mellanhänder mellan energiproducerande kunder och tredjepartsköpare. Ett krav för att delta i budgivningen är dock att som VPP kunna lägga ett bud som specificerar hur stor effekt som kan produceras under en viss timme, minst 48 timmar i framtiden. Här kommer prognoser in i bilden. Denna rapport jämför precisionen för åtta olika maskininlärningsmodeller som har i uppgift att predicera effektproduktion med hjälp av samma data från ett elbilsbaserat VPP. Denna studie undersöker också vilka slutsatser som kan dras angående kundbeteenden från given data och ger strategiska rekommendationer baserat på studiens resultat. Efter utvärdering av resultaten kunde det konstateras att Deep Learning-modeller överträffade autoregressiva modeller, som i sin tur överträffade Random Forest Regression och Support Vector Regression. Vad gäller kundbeteenden i given data, kan sägas att en låg negativ korrelation fanns mellan spotpriser och effektproduktion, vilket tyder på att kunder begränsar laddning av elbilar när spotpriserna är höga. Vidare kan sägas att mer effekt generellt sett produceras på kvällar och helger. Studiens data visar också på en autokorrelation med en eftersläpning (lag) på 24 timmar, vilket tyder på att laddningsmönster under en given dag influerar laddningsmönster under nästkommande dag.

<p> Three symbiotic systems are considered. These include the possibility of coupling the tritium production in a fission reactor with the fertile conversion in a fusion blanket. Equations for the fuel dynamics, power output, efficiency and costs of a symbiotic, selfcontained power station are developed and evaluated for a specific, 1500 MWe fission reactor operating on a thorium cycle and some fusion parameters. It is concluded that a system using the tritium produced in a fission reactor has lower costs and increased power output when compared to an alternate system. </p> / Thesis / Master of Engineering (MEngr)

No description available.

This study presents the design and optimization of a test rig tailored for upcoming wind turbine design applications. Initial decisions were made regarding component selection, focusing on a gearbox, electric motor, and motor controller. Requirements included continuous power output of 300 kW from the electric motor and the gearbox's ability to handle specified torque and reduce input speed to match the structural limitations. Key challenges revolved around gearbox design and performance, necessitating a right-angle configuration for converting horizontal to vertical torque efficiently. To meet the rotational speed requirements, a 30 to 1 ratio gearbox was selected, ensuring compatibility with the maximum structural rotational speed of 50 revolutions per minute. The electric motor, pivotal in the drivetrain, was chosen based on a balance between economic viability and rotational speed, resulting in a four-pole motor configuration. Coupling mechanisms were employed to connect the motor and gearbox, facilitating energy transfer between shafts. A motor controller was integrated to regulate current flow, voltage application, and frequency modulation, enhancing operational control and adaptability to specific requirements. Radial ball bearings were selected to minimize energy expenditure during rotation, particularly due to downward compressive forces. The test rig setup, situated indoors on a concrete floor, mandated a metal plate foundation to ease component attachment without drilling into the floor. Data simulations were conducted to determine bolt specifications capable of withstanding motor-induced forces. Furthermore, collaboration with industry experts facilitated component selection and quotation analysis, ensuring an optimized drivetrain solution meeting both technical and economic criteria. This research contributes to the advancement of wind turbine design testing methodologies, providing insights into component selection, integration, and optimization for enhanced performance and reliability.

Many athletes incorporate high training volumes and limited recovery periods into their training regimes. This may disrupt the fragile balance and the accumulation of exercise stress may exceed an athlete's finite capacity of resistance. A state of elevated fatigue, increased mood disturbance and decreased exercise performance can result. This is commonly known as overreaching and if increased training and limited recovery is continued, it is believed that the more serious state of overtraining may develop. This is relatively commonly experienced in athletes, however little scientific investigation has been conducted to determine the characteristics and underlying mechanisms. The overall aim of this thesis was to gain a greater understanding of the state of overreaching and to specifically provide new information on potential markers of this state as well as possible mechanisms. To study the cumulative effects of exercise stress and subsequent recovery on performance changes, fatigue indicators and possible mechanisms, the training of endurance cyclists was systematically controlled and monitored in two separate investigations. A number of variables were assessed including performance, physiological, biochemical, psychological, immunological and hormonal variables. In addition heart rate variability and serotonergic responsiveness were also assessed. Some of the more pertinent effects of overreaching included an increase in heart rate variability, a reduction in carbohydrate oxidation, an increase in serotonergic responsiveness and a reduction in stress hormone concentrations. These results suggest that autonomic imbalance in combination with decreased hormonal release appears to be related to the decline in performance and elevated fatigue apparent in overreached athletes. Additionally it also appears that alterations in the hypothalamic-pituitary adrenal axis may occur in overreached athletes.

La récupération, grâce aux hydroliennes, de l’énergie cinétique de courants marins et fluviaux constitue une source d’énergie renouvelable considérable et prédictible. La simulation fine, par une description statistique instationnaire de type URANS, de l’écoulement autour d’une hydrolienne isolée à axe vertical, bi-rotor et munie d’un carénage (hydrolienne de type HARVEST) donne accès à une estimation précise de la puissance produite. Cependant, le coût élevé de cette approche URANS la rend inadaptée à la simulation d’un parc de machines. Une analyse de la littérature conduit à retenir un modèle basse-fidélité de type Blade Element Momentum (BEM) pour décrire à moindre coût l’effet du rotor de la turbine sur l’écoulement, dans le contexte d’une description 2D (coupe horizontale). La performance de l’hydrolienne est alors prédite par un calcul RANS incluant des termes sources distribués dans un anneau rotor virtuel et conservant le maillage des parties fixes (carénage). Ces termes sources sont construits grâce à une procédure originale exploitant les conditions locales de l’écoulement en amont des cellules du rotor virtuel et le débit de l’écoulement traversant l’hydrolienne. Les coefficients hydrodynamiques utilisés pour le calcul des termes sources BEM-RANS sont construits une fois pour toutes en exploitant une série de simulations URANS préliminaires ; ils intègrent les effets du carénage et le fonctionnement de chaque rotor à une vitesse de rotation optimale (maximisant la puissance produite) grâce au système de régulation de l’hydrolienne. Le modèle BEM-RANS développé est validé par comparaison avec des simulations URANS de référence : il fournit une estimation fiable de la puissance produite (erreur de quelques % par rapport à l’approche URANS) pour un coût réduit de plusieurs ordres de grandeur. Ce modèle est appliqué à l'analyse de la puissance produite par une rangée d’hydroliennes HARVEST dans un canal pour différents facteurs de blocage et d’espacement latéral ainsi qu’à une ferme marine composée de trois hydroliennes. / The capture, thanks to hydrokinetic turbines, of the kinetic energy generated by sea and river currents provides a significant and predictable source of renewable energy. The detailed simulation, using an unsteady statistical description of URANS type, of the flow around an isolated water turbine of HARVEST type (cross flow vertical axis ducted water turbine) provides an accurate estimate of the power output. However, the cost of the URANS approach is much too expensive to be applied to a farm of several turbines. A review of the literature leads to select a low-fidelity model of Blade Element Momentum (BEM) type to describe at a reduced cost the rotor effect on the flow, in a 2D context (horizontal cross-section). The turbine performance is then predicted using a steady RANS simulation including source terms distributed within a virtual rotor ring and preserving the mesh of the turbine fixed parts (duct). These source terms are derived using an original procedure which exploits both the local flow conditions upstream of the virtual rotor cells and the flow rate through the turbine. The hydrodynamic coefficients used to compute the BEM-RANS source terms are built once for all from a series of preliminary URANS simulations; they include the effects of the duct on the flow and the rotor operating at optimal rotational speed (maximizing the power output) thanks to the turbine regulation system. The BEM-RANS model is validated against reference URANS simulations: it provides a reliable prediction for the power output (within a few % of the URANS results) at a computational cost which is lowered by several orders of magnitude. This model is applied to the analysis of the power produced by a row of Vertical Axis Water Turbines in a channel for various values of the blockage ratio and lateral spacing as well as to a 3-machine sea farm.

No description available.

Background: A squat is a common exercise that is used in many areas of strength training and for different purposes and the literature is inconclusive when it comes to whether the weight lifting belt (WB) affects performance and/or is injury-preventing. The use of breathing techniques is common during heavy lifting and therefore the practice of the breathing teqnice; valsalva maneuver (VM) may be of interest to study and if this along with the WB can provide some advantages in power output and velocity. Aim: The specific aim of the study was to evaluate whether the velocity in the eccentric and the concentric phase of the squat, and the peak velocity in the concentric phases are affected in power output through the use of the VM when the subjects use or did not use a WB. Method: Fifteen subjects (10 men and 5 women) volunteered freely to participate and did a total of 12 squats divided in four different sets with three repetitions each on 75% of their self-reported one repetition maximum (1RM). The first two sets were either with or without WB and the third and fourth sets were either with or without the practice of the VM. The three conditions (with WB, with WB + VM and VA only) were compared to each other and to the control group (without any instructions and no WB) in terms of power output and velocity in the eccentric, concentric and peak velocity in the concentric phase of the squat. Result: There was no significant difference in power output when comparing the four different test conditions. The velocity in the eccentric, concentric and peak velocity in the concentric phase did not have a significant difference between the different test conditions. Conclusions: This study shows a different output compared to previous literature. The WB and the practice of VM did not affect the power output and velocity in a squat, alone or together. / Bakgrund: Det finns många olikheter i litteraturen när det gäller huruvida tyngdlyftarbältet påverkar prestationen och/eller om det minskar skaderisken. En knäböj är en vanlig övning som används inom många områden av styrketräning och för olika ändamål. Användning av andningstekniker är vanligt vid tunga lyft och därför kan utförandet av andningstekniken; valsalvamanövern vara av intresse att studera och om det tillsammans med lyftbältet kan ge effekt på effektutveckling och hastighet i lyft. Syfte: Syftet med studien var att utvärdera hastigheten i en knäböjs olika faser (excentriska, koncentriska och topphastigheten i den koncentriska fasen) och hur effektutvecklingen påverkas av lyftarbälte och valsalvamanövern. Metod: Femton personer (10 män och 5 kvinnor) deltog frivilligt och utförde totalt 12 knäböj i fyra olika sets med tre repetitioner på 75 % av testpersonernas självrapporterade 1RM. De första två seten var utförda antingen med eller utan tyngdlyftarbälte och de tredje och fjärde seten var utförda antingen med eller utan utövande av valsalvamanövern. Dessa tre förhållanden ( med lyftarbälte, med lyftarbälte + VA och VA endast) jämfördes med varandra och med kontrollgruppen ( ingen VM och inget lyftarbälte) med avseende på effektutveckling och hastigheten i den excentriska, koncentriska och topphastighet i knäböjens koncentriska fas. Resultat: Effektutvecklingen gav ingen signifikant skillnad i någon av de fyra olika förutsättningarna (med lyftarbälte, utan lyftarbälte, med bälte och valsalvamanövern och utan bälte och valsalvamanövern). Hastigheten i den excentriska, koncentriska och topphastigheten i den koncentriska fasen visade ingen signifikant skillnad mellan de fyra olika seten. Konklusion: Studien visade ingen skillnad vilket kan jämföras med tidigare litteratur där en skillnad fanns. Lyftarbältet och utförandet av valsalva manövern påverkade inte effektutvecklingen och/eller hastigheten när en knäböj utfördes.