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Proactive ergonomics is generally considered to be a more efficient and cost effective way of designing working environments than reactive ergonomics. It often requires preemptively selecting working postures and forces to reduce potential injury risk. One major issue with proactive ergonomic design is correctly identifying the true manual forces that will be required of a worker to complete defined tasks. Typically, these forces are represented as in direct opposition to the forces required by a particular task. However, this is likely an oversimplification as forces often act in different directions than the task-required direction to increase required force level, enhance balance and reduce joint moments, depending on specific experimental conditions. This study aims to quantify these off-axis forces as they change with different required on-axis force intensities. This thesis evaluated the effects of force intensity on the presence of off-axis forces across four conditions, which included free and constrained postures, and with and without off-axis force. Eighteen female subjects performed static, unilateral, manual pushing and pulling exertions while seated and were limited to force contributions from the right upper extremity. Hand forces and location of bony landmarks were collected from each subject and force intensity consisted of both maximal and submaximal levels (5% to 50% of the maximum producible on-axis force in increments of 5%). All principle direction forces were scaled to the on-axis force level and anatomically relevant joint moments scaled to the maximum capacity joint moment. The main objective of this study was to analyze off-axis force production as force intensity was increased under various constraint conditions. The highest maximum on-axis force was in the fully free condition (off-axis force allowed and posture unconstrained) and as conditions became more constrained for both pushing and pulling exertions, maximum on-axis force production decreased (p=<0.0001). For submaximal exertions in the free posture, participants used off-axis forces to target the shoulder flexion-extension moment by pushing increasingly upwards (p=0.0122) and to the left by 5.6% on-axis (p=0.0025), and by pulling 12.6% on-axis downward (p=<0.0001) and 4.7% on-axis rightward (p=0.0024) compared to when off-axis force was not allowed. When comparing the free to the constrained posture while allowing off-axis force, participants pushed downwards instead of upwards by a difference of 12.9% on-axis (p=0.0002) and pulled less downward (becoming slightly upward) by an increasing difference (p=0.0002) and from decreasing to increasing rightward (p=0.0006). These changes in off-axis force showed a unifying strategy of using less shoulder flexion-extension strength by targeting wrist and elbow moments for pushing and pulling exertions. When in the constrained posture allowing and not allowing off-axis force resulted in more internal elbow flexion (p=0.0003) moment during pushing, and less internal shoulder flexion (p=0.0092), more internal shoulder adduction (p=0.0252), more to less internal elbow supination (p=0.0415), and increasingly less internal wrist flexion (p=0.0296) moments during pulling, which verified previously observed strategies. Finally, for both maximal and submaximal exertions, pulling was more sensitive to changes in off-axis forces compared to pushing which was more sensitive to postural flexibility. In conclusion, the underlying principles as to how and why off-axis forces change provides valuable knowledge to ergonomists so that they can more accurately predict force production in workplace design, ultimately reducing the potential for injury.

Currently, wind energy presents an excellent opportunity to satisfy the growing demand without the supply and environmental problems associated with conventional energy. The engineering in wind turbines is not fully mature. There are still phenomenon, particularly dynamic stall, that cannot accurately be modeled or controlled. Dynamic stall contributes to fatigue stress and premature failure in many turbine components. The three dimensionality of dynamic stall makes these structures unique for wind turbines. Currently, flow visualization of dynamic stall on a wind turbine rotor has not been achieved. These visualizations can reveal a lot about the structures that contribute to dynamic stall. Particle Image Velocimetry (PIV) is a powerful experimental technique that can take multiple non-intrusive flow measurements simultaneously of planar flow. Using high-speed cameras time resolved PIV can reveal the transient development of a given flow field. This technique is ideally suited to gain a better understanding of dynamic stall. A custom wind turbine is being built at the University of Waterloo to allow such measurements on the blade. A high speed camera is mounted on the hub and will take measurements within the rotating domain. Mirrors are used so that laser illumination rotates with the blade. The wind turbine will operate in controlled conditions provided by a large wind tunnel. High speed pressure data acquisition will be used in conjunction with PIV to get an understanding of the forces associated with the flow structures. Computational fluid dynamics was used to size the rotor within the wind tunnel. Laser based measurements required special considerations for stiffness. Many revealing experiments will be made possible by this apparatus. First, the flow structures responsible for the various forces can be identified. Quantitative measurements of the flow field will identify the development of the stall vortex. The quantified flow structures can be used verify and improve models. The high spatial resolution of PIV can map the three dimensional flow structure in great detail. The experimental apparatus is independent of the blade geometry, as such multiple blades can be used to identify the effect of blade geometry. Finally flow control research in the field of aviation can be applied to control dynamic stall.

Examensarbetet är utfört på avdelningen för Fluida och mekatroniska system vid Linköpings universitet i uppdrag åt Sunfab Hydraulics AB. Höga ljudnivåer är en stor nackdel vid användning av hydrauliska system. Ofta är det hydraulmaskiner av deplacementtyp som står för en stor del av ljudemissionerna. Eftersom maskinerna arbetar med stora tryckskillnader uppstår flödespulsationer vid in- och utlopp som fortplantar sig vidare i systemet. Dessa medför påfrestningar på maskinen som kan leda till läckage eller haveri. Flödespulsationer kan delas upp i två delar; kinematiska och kompressionsberoende. De kinematiska pulsationerna beror på det begränsade antalet cylindrar och kolvarnas varierande hastighet. På grund av oljans kompressibilitet uppstår pulsationer när cylindertrycket hastigt växlar mellan trycknivåerna. Arbetet har resulterat i en modell i programmet HOPSAN som kan simulera flödesdynamiken i en axialkolvmaskin med fast deplacement av typen bent-axis. I modellen kan bland annat ventilskivans geometri förändras för att studera hur flödespulsationerna påverkas vid olika driftspunkter. Simuleringsmodellen har med två-mikrofon metoden validerats för en maskin med deplacement 47.1 cm3/varv. Mätutrustningen som använts är anpassad för pumpar vilket innebär att vid mätningarna på motorlocket kördes maskinen som pump. För att underlätta tillverkningen av krypspår borras små hål vid dess spets. Dessa finns implementerade i modellen för att undersöka hur flödespulsationerna påverkas. Simuleringar påvisar ett större läckflöde mellan njurarna vilket resulterar i en liten minskning av den volymetriska verkningsgraden vid låga varvtal. För att bättre kunna använda modellen till utveckling av befintliga maskiner borde Sunfab se över om hålen kan tas bort. För- och nackdelar med stängd respektive öppen geometri kan undersökas i modellen. Den senare innebär att ett korsande flöde mellan hög- och lågtryckssidan tillåts. Simuleringar visar att vid låga varvtal är den volymetriska verkningsgraden lägre för motorlock med öppen geometri. Stängd geometri ger bättre startmoment på grund av frånvaron av läckflöde men ger däremot större flödespulsationer. Optimering av krypspåren visar att maximala tvärsnittsarean kan justeras lite för att minska amplituden av flödespulsationerna.

In this thesis it has been investigated if LQG control could be used to mitigate torsional oscillations in a variable speed, fixed pitch wind turbine. The wind turbine is a vertical axis wind turbine with a 40 m tall axis that is connected to a generator. The power extracted by the turbine is delivered to the grid via a passive rectifier and an inverter. By controlling the grid side inverter the current is controlled and hence the rotational speed can be controlled. A state space model was developed for the LQG controller. The model includes both the dynamics of the electrical system as swell as the two mass system, consisting of the turbine and the generator connected with a flexible shaft. The controller was designed to minimize a quadratic criterion that punishes both torsional oscillations, command following and input signal magnitude. Integral action was added to the controller to handle the nonlinear aerodynamic torque. The controller was compared to the existing control system that uses a PI controller to control the speed, and tested usingMATLAB Simulink. Simulations show that the LQG controller is just as good as the PI controller in controlling the speed of the turbine, and has the advantage that it can be tuned such that the occurrence of torsional oscillations is mitigated. The study also concluded that some external method of dampening torsional oscillations should be implemented to mitigate torsional oscillations in case of a grid fault or loss of PWM signal.

Currently, wind energy presents an excellent opportunity to satisfy the growing demand without the supply and environmental problems associated with conventional energy. The engineering in wind turbines is not fully mature. There are still phenomenon, particularly dynamic stall, that cannot accurately be modeled or controlled. Dynamic stall contributes to fatigue stress and premature failure in many turbine components. The three dimensionality of dynamic stall makes these structures unique for wind turbines. Currently, flow visualization of dynamic stall on a wind turbine rotor has not been achieved. These visualizations can reveal a lot about the structures that contribute to dynamic stall. Particle Image Velocimetry (PIV) is a powerful experimental technique that can take multiple non-intrusive flow measurements simultaneously of planar flow. Using high-speed cameras time resolved PIV can reveal the transient development of a given flow field. This technique is ideally suited to gain a better understanding of dynamic stall. A custom wind turbine is being built at the University of Waterloo to allow such measurements on the blade. A high speed camera is mounted on the hub and will take measurements within the rotating domain. Mirrors are used so that laser illumination rotates with the blade. The wind turbine will operate in controlled conditions provided by a large wind tunnel. High speed pressure data acquisition will be used in conjunction with PIV to get an understanding of the forces associated with the flow structures. Computational fluid dynamics was used to size the rotor within the wind tunnel. Laser based measurements required special considerations for stiffness. Many revealing experiments will be made possible by this apparatus. First, the flow structures responsible for the various forces can be identified. Quantitative measurements of the flow field will identify the development of the stall vortex. The quantified flow structures can be used verify and improve models. The high spatial resolution of PIV can map the three dimensional flow structure in great detail. The experimental apparatus is independent of the blade geometry, as such multiple blades can be used to identify the effect of blade geometry. Finally flow control research in the field of aviation can be applied to control dynamic stall.

<p>Glucose metabolism remains an intensely explored topic of cancer biology since the initial discoveries of Otto Warburg nearly 80 years ago. Many solid tumors metabolize glucose primarily to lactate despite the availability of oxygen, revealing a dependence on glycolysis that may serve as a basis for targeted therapy. In particular, a diet devoid of carbohydrate may minimize the growth capabilities of glucose-dependent cancers. As our interests lie in prostate cancer, we examined whether a ketogenic diet devoid of carbohydrate (NCKD) would reduce the growth rate of tumors derived from human prostate cancer cell lines in a murine xenograft model.</p> <p>Our initial experiments utilized the LAPC-4 cell line, a human androgen-sensitive prostate cancer cell line, in a SCID-mouse xenograft model to determine the effects of an NCKD on tumor growth and animal survival relative to two other diets: (1.) a Western-type diet (WD) reflecting consumptions patterns of men diagnosed with prostate-cancer in the Western world and (2.) a low-fat diet (LFD) representing the present standard of care. Following this study, we conducted a second study utilizing a different human prostate cancer cell line (LNCaP) in order to assess whether our initial observations were robust across multiple prostate cancer tumor models and to also further explore the molecular underpinnings of our observations. Both studies revealed the NCKD leads to a reduction in tumor growth rate and greater overall mouse survival relative to the WD. In addition, the NCKD was equivalent in these parameters to the LFD. We also observed key associations between survival and extent of urinary ketosis as well as favorable changes in insulin and insulin-like growth factor-1 (IGF-1) and gene expression that would be predictive of prolonged survival in mice consuming the NCKD.</p> <p>We believe these data provide compelling evidence to consider a potential therapeutic role for dietary carbohydrate restriction in prostate cancer. We hope these results ultimately serve as a basis to conduct future clinical trials assessing whether dietary carbohydrate restriction, either alone or in combination with more conventional therapies, provides clinicians with an additional weapon against prostate cancer.</p> / Dissertation

Shear-mode thin film bulk acoustic resonator (TFBAR) devices with c-axis tilted AlN films are fabricated for the application of liquid sensors. To fabricate shear-mode TFBAR devices, the off-axis RF magnetron sputtering method for the growth of piezoelectric AlN thin films is adopted and influences of the relative distance and the sputtering parameters are investigated. The shrar-mode phenomenon of a TFBAR results from the tilted crystalline orientation of AlN thin films. In this thesis, the AlN thin films are deposited with tilting angles of 15¢X and 23¢X, set by controlling the deposition parameters. The properties of the AlN thin films are investigated by X-ray diffraction and scanning electron microscopy. The frequency response is measured using an HP8720 network analyzer and a CASCADE probe station. The frequency response of the TFBAR device with 23¢X tilted AlN thin film is measured to reveal its ability to provide shear-mode resonance. The resonance frequencies of the longitudinal and shear modes are 2.07 GHz and 1.17 GHz, respectively. To investigate the sensing characteristics of TFBAR, two basic experiments of mass and liquid loading are carried out. The sensitivities of the longitudinal and shear modes to mass loading are calculated to be 2295 Hz cm2/ng and 1363 Hz cm2/ng with the mechanical quality factors of 588 and 337, respectively. However, the mechanical quality factors of the longitudinal mode of TFBAR without and with a liquid loading decreased from 588 to 0, whereas those remain almost the same for the shear mode under liquid loading. The sensitivities of the longitudinal and shear modes are calculated to be 0 and 17.88 Hz cm2/£gg for liquid loading.

A novel liquid sensor is designed and fabricated by using thin film bulk acoustic resonator (TFBAR) devices with c-axis 23¢X-tilted ZnO films. To fabricate TFBAR devices, the off-axis RF magnetron sputtering method for the growth of piezoelectric ZnO thin films is adopted. The influences of the relative distance and sputtering parameters are investigated. In this report, the piezoelectric ZnO thin films with tilting angle of 23¢X are set by controlling the deposition parameters. The properties of the c-axis 23¢X-tilted ZnO thin films are investigated by X-ray diffraction and scanning electron microscopy. The frequency response is measured using an HP8720 network analyzer with a CASCADE probe station. The TFBAR devices with 23¢X-tilted ZnO thin films display shear and longitudinal resonant modes at 752.75 MHz and 1.70 GHz, respectively. The mechanical quality factors (QL for longitude mode and QS for shear mode) are thus the important parameters of dual-mode TFBAR devices used in liquid environments. QL decreased from 545 to 0 upon in liquid loading, whereas QS remained almost unchanged at 296 in all environments. Moreover, the sensitivity of the shear mode to liquid loading is calculated to be 13 Hz cm2/£gg.