1,799 research outputs found
Numerical simulation of the airflowârivulet interaction associated with the rain-wind induced vibration phenomenon
Rain-wind induced vibration is an aeroelastic phenomenon that occurs on the inclined cables of cable-stayed bridges. The vibrations are believed to be caused by a complicated nonlinear interaction between rivulets of rain water that run down the cables and the wind loading on the cables due to the unsteady aerodynamic flow field. Recent research at the University of Strathclyde has been to develop a numerical method to simulate the influence of the external air flow on the rivulet dynamics and vice versa, the results of which can be used to assess the importance of the water rivulets on the instability. The numerical approach for the first time couples a Discrete Vortex Method solver to determine the external flow field and unsteady aerodynamic loading, and a pseudo-spectral solver based on lubrication theory to model the evolution and growth of the water rivulets on the cable surface under external loading. The results of the coupled model are used to assess the effects of various loading combinations, and importantly are consistent with previous full scale and experimental observations of rain-wind induced vibration, providing new information about the underlying physical mechanisms of the instability
Developing preparedness for flexible delivery of training in enterprises
On a basis of research and literature review, Smith, in 2001, suggested a model for the development of preparedness of learners and their workplaces to support the flexible delivery of training in enterprises. Using the model as a framework, he then developed a detailed set of strategies that may be used in operating workplaces to develop learners and workplaces for effective flexible delivery. The research reported here was designed to test that strategy set in 12 different enterprises to assess the feasibility of their implementation in operating workplaces. The research shows that a majority of suggested strategies are feasible for implementation; some are feasible with qualification; and a minority were not seen as feasible.<br /
Importance of Outcrossing for Fruit Production in Slickspot Peppergrass, \u3cem\u3eLepidium Papilliferum\u3c/em\u3e L. (Brassicaceae)
Plants with insect-mediated pollination are often assumed to be obligate outcrossers; i.e., pollen must be supplied from flowers of other individuals for pollination and subsequent fruit production. Indeed, many flowers with insect-mediated pollination exhibit incompatibility to their own pollen or have a separation in time between pollen production and maturation of the stigma on a given flower (Proctor et al. 1996). However, because the breeding systems of plants are diverse and include varying levels of outcrossing and selfing, experiments are required to determine whether pollination in a particular species occurs via outcrossing, self-pollination, or both. Here I report the results of such a study on slickspot peppergrass, Lepidium papilliferum L. (Brassicaceae), a rare mustard endemic to sagebrush-steppe habitat in southwestern Idaho
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Problem solving from textbook examples
There has been a great deal of research into students' use of examples when solving problems in textbooks. Much of this work has been within the framework of analogical problem solving (APS). Indeed many researchers believe they can build adequate models of how students learn and solve exercise problems by analogy to worked examples. In the first part of this thesis I argue that this view of problem solving from examples is inappropriate and often misleading. Most students learning a subject for the first time tend to imitate examples. Imitative Problem Solving UPS)is a weak form of analogical problem solving. APS accounts assume that a solver has a representation of an earlier problem in memory. The difficulties involved are accessing that source problem and adapting it to solve the current one. WS does not assume t at the source is represented in memory, and even when the source example is available( as in textbook examples), the student may not understand it well enough to be able to adapt it to new situations.The second part of the thesis presents an interpretation theory for analysing both texts and the behaviour of solvers using those texts to solve exercise problems.The third part applies the interpretation theory to the solution explanation of a simple algebra word problem. Where an example problem fails to map directly onto an exercise problem, or where inferences have to be made to understand it, the solver win be unable to imitate the example and hence will have difficulties in proportion to the mapping inequalities between the two problems. That is, the interpretation theory allows us to predict precisely where solvers will have difficulty using an example to solve an exercise problem of the same type.The final part presents experimental tests of these predictions. The results confirm that the interpretation theory analysis can correctly identify possible areas of difficulty for the student due to a) the way an example problem is structured, and b) the nature of the transfer task
Timing verification of dynamically reconfigurable logic for Xilinx Virtex FPGA series
This paper reports on a method for extending existing VHDL design and verification software available for the Xilinx Virtex series of FPGAs. It allows the designer to apply standard hardware design and verification tools to the design of dynamically reconfigurable logic (DRL). The technique involves the conversion of a dynamic design into multiple static designs, suitable for input to standard synthesis and APR tools. For timing and functional verification after APR, the sections of the design can then be recombined into a single dynamic system. The technique has been automated by extending an existing DRL design tool named DCSTech, which is part of the Dynamic Circuit Switching (DCS) CAD framework. The principles behind the tools are generic and should be readily extensible to other architectures and CAD toolsets. Implementation of the dynamic system involves the production of partial configuration bitstreams to load sections of circuitry. The process of creating such bitstreams, the final stage of our design flow, is summarized
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