Osteoarthritis (OA) is a group of diseases entailing degradation of joints, and has been designated as one of the key conditions for special attention during the World Health Organization’s Bone and Joint Decade (2000-2010) (Brooks & Hart, 2000). Research has demonstrated that body weight is the number one modifiable risk factor associated with the onset and progression of knee OA (Felson, 1996). However, exercise programs that aim to initiate weight loss and improve pain and function in knee OA often increase loading on the knee joint, contributing to degeneration of the knee and progression of the disease (Miyazaki et al, 2002). The introduction of a new anti-gravity treadmill, which utilizes a technology called Lower Body Positive Pressure (LBPP), allows the examination of the relationship between weight, knee pain and knee loading via knee acceleration during exercise. The null hypothesis states that there will be no significant difference in knee pain, knee function and knee joint acceleration when comparing full weight bearing and LBPP treadmill walking exercise in a young knee OA population. Twenty-two overweight/obese patients with mild or moderate early-onset knee OA were recruited to complete two 25 minute treadmill walking sessions (one full weight-bearing and one LBPP walking session) one week apart and two walkway walking sessions. Knee pain and knee acceleration were recorded. Paired t-tests and ANOVAs were used to compare conditions. On average, an LBPP of 12.3% body weight reduction reduced knee pain in our population. Knee pain was significantly lower during LBPP walking than during full weight-bearing walking. Knee acceleration decreased with increasing LBPP. Heel strike and toe-off data from walkway walking trials illustrated significantly different knee acceleration about the knee (slow walking loads were lower / fast walking were higher), as compared to treadmill walking sessions. This study illustrates that treadmill walking at a minimal level of LBPP can decrease knee pain and attenuate knee joint loads while allowing patients to complete exercise programs aimed at initiating weight loss and improving pain and function in knee OA. LBPP appears to be a promising tool for rehabilitation for those with painful knee OA and other lower body musculoskeletal conditions.

A co-simulation methodology is explored whereby a finite element code and a multi-body dynamics code featuring flexible cantilevered beams can be coupled and interactively executed. The floating frame of reference formulation is used to develop the equations of motion. The floating frame is fixed at the blade root. Such a formulation results in ordinary differential equations without added algebraic constraints. A variety of loose coupling and tight coupling schemes are examined for this problem. To synchronize the coupling variables, a Gauss-Seidel type iterative algorithm is used. The resulting fixed-point iterations are accelerated using Aitken’s adaptive relaxation technique. The methodology is evaluated for FAST, a wind turbine aeroelastic simulation code developed by NREL. As with FAST, many multi-body codes which can model flexibility employ modal methods. A proposed addition for FAST to simulate flexible effects using a finite element method module offers a potential to include a variety of non-linearities and also provides possibilities for using a high-fidelity aerodynamics module. The coupling schemes are compared and their applicability and limitations for different scenarios are pointed out. Results validating the approach are provided.

In order to accelerate logic simulation, it is highly beneficial to simulate the circuit design on FPGA hardware. However, limited hardware resources on FPGAs prevent large designs from being implemented on a single FPGA. Hence there is a need to partition the design and simulate it on a multi-FPGA platform. In contrast to existing FPGA-based post-synthesis partitioning approaches which first completely flatten the circuit and then possibly perform bottom-up clustering, we perform a selective top-down flattening and thereby avoid the potential netlist blowup. This also allows us to preserve the design hierarchy to guide the partitioning and to make subsequent debugging easier. Our approach analyzes the hierarchical design and selectively flattens instances using two metrics based on slack. The resulting partially flattened netlist is converted to a hypergraph, partitioned using a public domain partitioner (hMetis), and reconverted back to a plurality of FPGA netlists, one for each FPGA of the FPGA-based accelerated logic simulation platform. We compare our approach with a partitioning approach that operates on a completely flattened netlist. Static timing analysis was performed for both approaches, and over 15 examples from the OpenCores project, our approach yields a 52% logic simulation speedup and about 0.74x runtime for the entire flow, compared to the completely flat approach. The entire tool chain of our approach is automated in an end-to-end flow from hierarchy extraction, selective flattening, partitioning, and netlist reconstruction. Compared to an existing method which also performs slack-based partitioning of a hierarchical netlist, we obtain a 35% simulation speedup.

Beams of polarized protons play an important part in the study of the spin dependence of the nuclear force by measuring the analyzing power in nuclear reactions. The source at iThemba LABS produces a beam of polarized protons that is pre-accelerated by an injector cyclotron (SPC2) to a energy of 8 MeV before acceleration by the main separated-sector cyclotron to 200 MeV for physics research. The polarized ion source is one of the two external ion sources of SPC2. Inside the ion source hydrogen molecules are dissociated into atoms in the dissociator and cooled to a temperature of approximately 30 K in the nozzle. The atoms are polarized by a pair of sextupole magnets and the nucleus is polarized by RF transitions between hyperfine levels in hydrogen atoms. The atoms are then ionized by electrons in the ionizer. The source has various sensitive devices, which influence beam intensity and polarization. Nitrogen gas is used to prevent recombination of atoms after dissociation. The amount of nitrogen and the temperature at which it is used plays a very important role in optimizing the beam current. The number of electrons released in the ionizer is influenced by the size and shape of the filament. Optimization of the source will ensure that beams of better quality (a better current and stability) are produced.

Convergence acceleration techniques for the iterative solution of system of equations arising in the discretisations of compressible flow problems governed by the steady state Euler or Navier-Stokes equations is considered. The system of PDE is discretised using a finite difference or finite volume method yielding a large sparse system of equations. A solution is computed by integrating the corresponding time dependent problem in time until steady state is reached. A convergence acceleration technique based on semicirculant approximations is applied. For scalar model problems, it is proved that the preconditioned coefficient matrix has a bounded spectrum well separated from the origin. A very simple time marching scheme such as the forward Euler method can be used, and the time step is not limited by a CFL-type criterion. Instead, the time step can asymptotically be chosen as a constant, independent of the number of grid points and the Reynolds number. Numerical experiments show that grid and parameter independent convergence is achieved also in more complicated problem settings. A comparison with a multigrid method shows that the semicirculant convergence acceleration technique is more efficient in terms of arithmetic complexity. Another convergence acceleration technique based on fundamental solutions is proposed. An algorithm based on Fourier technique is provided for the fast application. Scalar model problems are considered and a theory, where the preconditioner is represented as an integral operator is derived. Theory and numerical experiments show that for first order partial differential equations, grid independent convergence is achieved.

This study examines the effects of acceleration on fluid forces acting on the hand in swimming and presents a new pressure method to predict fluid forces acting on the accelerating hand. Swimmers and coaches require accurate information about swimmers� fluid forces, propulsion and drag, in order to improve performance. In general, swimmers are likely to generate propulsion mainly with their hands in the front crawl stroke, butterfly and back crawl stroke. Researchers have attempted to estimate the fluid forces on the hands with various techniques including a cinematographic method (a "quasi-static" approach), a pressure method and a numerical method of computational fluid dynamics. However, the effect of accelerations on fluid forces acting on the hand has not yet been well quantified. Understanding of the effect of acceleration on fluid forces on the hand can provide useful information to enhance swimming performance. Also the developments of a method to predict fluid forces acting on the accelerating hand in swimming can be used to evaluate swimming performance more accurately. The present study used a hand model attached to a load cell to measure forces in three orthogonal directions and pressure sensors to measure pressures on the hand model rotated in the flume. The model position was measured by a potentiometer fixed to the axis of the model rotation. The quantification of the effect of acceleration was based on a simple theoretical understanding for fluid mechanics, using the inertia coefficients and the coefficients of fluid forces, that is widely accepted in other disciplines. The quantification was focused mainly in the direction tangential to the model rotation because the magnitude of the velocity changed in this direction. The overall effect of acceleration on fluid forces on the hand model was that the inertia coefficients increased rapidly in the early phase of the model movement, then in the final deceleration phase of model movement the inertia coefficients decreased to a negative value and then became small. The inertia coefficient increased in the impulsive start of the hand model, indicating that fluid forces acting on the hand increased as accelerations of the hand increased. This result was consistent with the simple theoretical understanding to induce additional fluid forces on the hand, that is, fluid forces on the hand increased as accelerations increased. However, the inertia coefficient decreased and reached large negative values in the late phase of the model movement involving decelerated motion, indicating that fluid forces on the hand increased as acceleration of the hand decreased to negative values (decelerations). That result was not consistent with the simple theoretical understanding to induce additional fluid forces on the hand because the simple theoretical understanding cannot take account of the preceding history of the fluid motion around the hand model associated with the formation of vortices. Thus, more sophisticated theory is needed. The dynamic pressure measured by the pressure sensors implied that the induced fluid forces might be due to large attached vortices behind the hand model. The hand was considered as a blunt body when the angle of attack was large (maximum = 90�) and an aerofoil shape when the angle of attack was small. The inertia coefficients became large when the hand model was set at the large angles of attack, indicating that the effect of accelerations on the hand model increased when the hand surface was directed to the on-coming flows (blunt body). For the development of the new pressure method, a regression analysis was used to build a single best-fit equation to predict fluid forces acting on the accelerating hand model. The single best-fit equation was acquired for various orientations of the hand model. The accuracy of prediction of fluid forces acting on the accelerating hand model was checked by a root mean square (RMS) difference. The RMS difference by the pressure method was approximately half of the RMS difference by the "quasi-static" approach that has been a major method to predict fluid forces exerted by the hand in swimming. The present study has quantified the effect of acceleration on fluid forces acting on the hand in swimming and developed a new pressure method including acceleration effects to predict fluid forces acting on the accelerating hand.

Thesis (Ph.D.)--McMaster University, 2006. / Supervisors: K. Behdinan, A.D. Spence. Includes bibliographical references (leaves 225-238).

Thesis (Ed. D.)--UCLA, 2007. / Vita. Includes bibliographical references (leaves 160-172).

Thesis (Ed. D.)--Illinois State University, 2004. / Title from title page screen, viewed March 21, 2005. Dissertation Committee: Paul Baker, Margaret B. Kolloff (co-chairs), Patricia H. Klass, Lucille T. Eckrich. Includes bibliographical references (leaves 176-183) and abstract. Also available in print.

Thesis, PlanB (M.S.)--University of Wisconsin--Stout, 2005. / Includes bibliographical references.