Nanoindentation has become a widely used technique to measure the mechanical properties of materials. Due to its capability to deform materials in micro- and nano-scale, nanoindentation has found more applications in characterizing the deformation behavior and determining the mechanical properties of thin films and coatings. This research deals with the characterization of samples received from Center for Advanced Microstructures and Devices (CAMD) and Integran Technologies Inc., Toronto, Canada and the objective of this investigation was to utilize the experimental data obtained from nanoindentation to determine the deformation behavior, mechanical properties of thin films on substrates and bulk materials, and the effect of geometrically different indenters (Berkovich, cubecorner, and conical). X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) analysis were performed on these materials to determine the crystal orientation, grain size of the material, and also to measure any substrate effects like pile-up or sin-in respectively. The results indicate that indentation size effect (ISE) strongly depends on shape of the indenter and less sensitive to penetration depth where as the hardness measurements depends on shape of indenter and depth of penetration. There is a negligible strain rate dependency of hardness at deeper depths and a significant increase in the hardness due to the decrease in grain size and results also indicate that there is no significant substrate effect on thin films for 10% and 20% of film thicknesses. Nanocrystalline material could not validate a dislocation based mechanisms deformation for indentation made by cubecorner and conical indenters in depths less than 1mm.

The majority of present-day horizontal axis wind turbine blade tips are simple designs based on historical trends. There is, however, some evidence that varying the design of the tip can result in significant changes in performance characteristics such as power output, noise, and structural loading. Very few studies have tested this idea on an actual rotating blade and there is much to be investigated. Thus, a project was devised to examine experimentally the effect of various tip designs on an operational rotating wind turbine rotor. A tapered, twisted blade 1.6 m in length was custom designed for use in the UW Wind Energy Research Facility using the blade element momentum (BEM) method. A coupling mechanism was designed such that the outer 10% of each blade could be exchanged to evaluate the effect of different tip designs. A set of three blades was fabricated out of fibre-reinforced plastic, while the tips were machined out of maple wood on a CNC milling machine. The blade was evaluated with a standard rectangular tip to establish baseline performance against which to compare the alternative tip configurations. The three-bladed rotor was tested at shaft speeds from 100 rpm to 240 rpm in wind speeds up to the facility maximum of 11.1 m/s. The rotor was found to have a maximum power coefficient of 0.42 at a tip speed ratio of 5.3 and a 1.45 kW rated power at a wind speed of 11 m/s. The performance was compared to predictions made using the BEM method with airfoil data generated using a modified Viterna method and the Aerodas method. While the Aerodas data was capable of predicting the power fairly accurately from 5 m/s to 10 m/s, the modified Viterna method predicted the entire curve much more accurately. Two winglet designs were also tested. The first (called Maniaci) was designed by David Maniaci of Pennsylvania State University and the other (called Gertz) was designed by the author. Both winglets were found to augment the power by roughly 5% at wind speeds between 6.5 m/s and 9.5 m/s, while performance was decreased above and below this speed range. It was calculated that the annual energy production could be increased using the Maniaci and Gertz winglets by 2.3% and 3%, respectively. Considering the preliminary nature of the study the results are encouraging and it is likely that more optimal winglet designs could be designed and evaluated using the same method. More generally, this study proved that the blades with interchangeable tips are capable of being used as an evaluation testbed for alternative wind turbine blade tip designs.

The majority of present-day horizontal axis wind turbine blade tips are simple designs based on historical trends. There is, however, some evidence that varying the design of the tip can result in significant changes in performance characteristics such as power output, noise, and structural loading. Very few studies have tested this idea on an actual rotating blade and there is much to be investigated. Thus, a project was devised to examine experimentally the effect of various tip designs on an operational rotating wind turbine rotor. A tapered, twisted blade 1.6 m in length was custom designed for use in the UW Wind Energy Research Facility using the blade element momentum (BEM) method. A coupling mechanism was designed such that the outer 10% of each blade could be exchanged to evaluate the effect of different tip designs. A set of three blades was fabricated out of fibre-reinforced plastic, while the tips were machined out of maple wood on a CNC milling machine. The blade was evaluated with a standard rectangular tip to establish baseline performance against which to compare the alternative tip configurations. The three-bladed rotor was tested at shaft speeds from 100 rpm to 240 rpm in wind speeds up to the facility maximum of 11.1 m/s. The rotor was found to have a maximum power coefficient of 0.42 at a tip speed ratio of 5.3 and a 1.45 kW rated power at a wind speed of 11 m/s. The performance was compared to predictions made using the BEM method with airfoil data generated using a modified Viterna method and the Aerodas method. While the Aerodas data was capable of predicting the power fairly accurately from 5 m/s to 10 m/s, the modified Viterna method predicted the entire curve much more accurately. Two winglet designs were also tested. The first (called Maniaci) was designed by David Maniaci of Pennsylvania State University and the other (called Gertz) was designed by the author. Both winglets were found to augment the power by roughly 5% at wind speeds between 6.5 m/s and 9.5 m/s, while performance was decreased above and below this speed range. It was calculated that the annual energy production could be increased using the Maniaci and Gertz winglets by 2.3% and 3%, respectively. Considering the preliminary nature of the study the results are encouraging and it is likely that more optimal winglet designs could be designed and evaluated using the same method. More generally, this study proved that the blades with interchangeable tips are capable of being used as an evaluation testbed for alternative wind turbine blade tip designs.

No description available.

This dissertation presents the results from an experimental study of three-dimensional turbulent tip gap flow in a linear cascade wind tunnel with 3.3% chord tip clearance with and without moving endwall simulation. Experimental measurements have been completed in Virginia Tech low speed linear cascade wind tunnel. A 24" access laser-Doppler velocimeter (LDV) system was developed to make simultaneous three-velocity-component measurements. The overall size of the probe is 24"à 37"à 24"and measurement spatial resolution is about 100 μm. With 24" optical access distance, the LDV probe allows measurements to be taken from the side of the linear cascade tunnel instead of through the bottom of the tunnel floor. The probe has been tested in a zero-pressure gradient two-dimensional turbulent boundary layer. Experimental measurements (oil flow visualization, pressure measurement, and LDV measurement) for the stationary wall captured the major flow structures of the tip leakage flow in the linear compressor cascade, such as tip leakage vortex, tip leakage vortex separation and tip separation vortex. Large velocity gradients in the tip leakage vortex separation, tip leakage vortex, and tip separation vortex regions generate large production of the Reynolds stresses and turbulent kinetic energy. One of the most interesting features of the tip leakage flow is the bimodal velocity probability histograms of the v component due to the unsteady motion of the flow in the interaction region between the tip leakage vortex and tip leakage jet. The tip separation vortex, tip leakage vortex separation, and tip leakage vortex contain most of turbulent kinetic energy and generate the highest dissipation rate. Relative motion of the endwall significantly affects the tip gap flow structures, especially in the near wall region. Compared to the stationary wall case, velocity gradients in the near wall region for the moving wall case are much smaller and lower velocity gradients in the near wall region cause the low production of Reynolds stresses and turbulent kinetic energy. Similar to the stationary wall case, high Reynolds stresses and turbulent kinetic energy values are mainly located in the vicinity of the tip leakage vortex and tip separation vortex region. The bimodal velocity probability histograms of the v component are also found at the same locations. The tip separation vortex with most of the turbulent kinetic energy generates the highest dissipation rate. The dissipation rate in the tip leakage vortex region is reduced with the decrease of turbulent kinetic energy under the moving wall effect. / Ph. D.

Tip growth, the mechanism by which hyphae, pollen tubes, root hairs, and algal rhizoids extend, is a complex and dynamic process that is characterised by localised extension at the extreme apex of the cell and morphological polarity. Its complexity suggests that high degree of regulation is needed to ensure that the characteristics of a particular cell type are maintained during growth. Regulation is likely to come about through bidirectional interplay between the cell wall and cytoplasm, although the mechanisms by which such cross-talk might occur are unknown. Results of this thesis present immunocytochemical data that indicate the presence of, and a close association between β4 integrin subunit-like proteins and proteins containing phosphorylated tyrosine residues in the oomycete Achlya bisexualis. When hyphae were plasmolysed, these proteins were present in wall-membrane attachment sites where there was also F-actin. A combination of immunoblots, ELISA, and a coupled enzyme assay suggest that phosphorylation may occur by both autophosphorylation and through the possible action of a tyrosine kinase. Tyrphostins, which are inhibitors of tyrosine kinases, abolished the anti-phosphotyrosine staining, inhibited the kinase activity, slowed tip growth and affected the organisation of the actin cytoskeleton, in a dose-dependent manner. In addition, results show A. bisexualis contains proteins epitopically similar to the rod domain of animal talin. However, these proteins do not co-localise with F-actin, and mainly locate at the sub-apical region in hyphae. For comparative purposes, Saccharomyces cerevisiae was also used to investigate the presence of β4 integrin subunit-like proteins and tyrosine phosphorylation. Immunoblotting showed that S. cereviaise contains a protein, which is found in the microsomal pellet fraction, that cross reacts with anti-β4 integrin subunit antibody. Furthermore, there are a number of proteins containing phosphotyrosine residues. Immunocytochemistry shows that this anti-β4 integrin staining is at the cortical site but anti-phosphotyrosine residues are distributed throughout cells. On the basis of an ELISA and a coupled enzyme assay, it is suggested that a soluble fraction of S. cerevisiae contains tyrosine kinase activity. This activity is strongly inhibited by tyrphostins.

No description available.

<p>In order to monitor a nuclear boiling water reactor fixed and movable detectors are used, such as the neutron sensitive LPRM (Local Power Range Monitors) detectors and the gamma sensitive TIP (Traversing Incore Probe) detectors. These provide a mean to verify the predictions obtained from core simulators, which are used for planning and following up the reactor operation. The core simulators calculate e.g. the neutron flux and power distribution in the reactor core. The simulators can also simulate the response in the LPRM and TIP detectors. By comparing with measurements the accuracy of the core simulators can be quantified. The core simulators used in this work are PHOENIX4 and POLCA7. Because of the complexity of the calculations, each fuel assembly is divided axially into typically 25 nodes, which are more or less cubic with a side length of about 15 cm. Each axial segment is simulated using a 2D core simulator, in this work PHOENIX4, which provides data to the 3D code, in this case POLCA7, which in turn perform calculations for the whole core. The core simulators currently use both radial pin weights and axial node weights to calculate the gamma TIP detector signal. A need to bring forward new weight factors has now been identified because of the introduction of new fuel designs. Therefore, the gamma TIP detector response has been simulated using a Monte Carlo code called MCNPX for a modern fuel type, SVEA-96 Optima2, which is manufactured by Westinghouse. The new weights showed some significant differences compared to the old weights, which seem to overestimate the radial weight of the closest fuel pins and the axial weight of the node in front of the detector. The new weights were also implemented and tested in the core simulators, but no significant differences could be seen when comparing the simulated detector response using new and old weights to authentic TIP measurements.</p>

In order to monitor a nuclear boiling water reactor fixed and movable detectors are used, such as the neutron sensitive LPRM (Local Power Range Monitors) detectors and the gamma sensitive TIP (Traversing Incore Probe) detectors. These provide a mean to verify the predictions obtained from core simulators, which are used for planning and following up the reactor operation. The core simulators calculate e.g. the neutron flux and power distribution in the reactor core. The simulators can also simulate the response in the LPRM and TIP detectors. By comparing with measurements the accuracy of the core simulators can be quantified. The core simulators used in this work are PHOENIX4 and POLCA7. Because of the complexity of the calculations, each fuel assembly is divided axially into typically 25 nodes, which are more or less cubic with a side length of about 15 cm. Each axial segment is simulated using a 2D core simulator, in this work PHOENIX4, which provides data to the 3D code, in this case POLCA7, which in turn perform calculations for the whole core. The core simulators currently use both radial pin weights and axial node weights to calculate the gamma TIP detector signal. A need to bring forward new weight factors has now been identified because of the introduction of new fuel designs. Therefore, the gamma TIP detector response has been simulated using a Monte Carlo code called MCNPX for a modern fuel type, SVEA-96 Optima2, which is manufactured by Westinghouse. The new weights showed some significant differences compared to the old weights, which seem to overestimate the radial weight of the closest fuel pins and the axial weight of the node in front of the detector. The new weights were also implemented and tested in the core simulators, but no significant differences could be seen when comparing the simulated detector response using new and old weights to authentic TIP measurements.

Steady, three-dimensional viscous numerical analysis of airflow over a rectangular NACA 0012 base wing (BW) with a rounded tip and with three NACA 0015 tip-sails (WTS) is performed. The flow physics and aerodynamic forces are studied at Reynolds numbers (Re) of 60,000 and 600,000, angles of attack (α) of 0, 5, 7.5, and 10°, and two sets of tip-sail dihedral angles (leading to trailing tip-sail): 50, 45, and 40° and 60, 45, and 30°. The Shear Stress Transport turbulence and intermittency-transition Reynolds number transitional turbulence models were used. For α > 0°, the WTS produced higher lift coefficients (CL) and drag coefficients (CD) than the BW. At Re = 600,000 and α > 0°, the CL/CD was higher for the WTS than the BW. Good agreement was seen with experimental data at Re = 600,000 for the BW results and the WTS CL but not the WTS CD. / October 2015