Numerical simulation of the airflow–rivulet 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

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

Basal narcosis: with special reference to the use of tri-bromethanol (Avertin)

CONCLUSIONS: (1) Every patient about to undergo a surgical operation should have the benefit of basal narcosis in some shape or form. (2) At the present time Avertin is the most satisfactory and generally applicable basal narcotic available. (3) Avertin is invariably safe if a dosage of 1 gram per kilogram of bodyweight be not exceeded. (4) Morphia should not be used as a premedicament as it is unnecessary and adds to the risk. (5) Avertin is essentially a basal narcotic and not a general anaesthetic. (6) The supplementary anaesthetic is of great importance in obtaining successful after -results and a simple technique for its administration is detailed. Emphasis is laid on the use of CO₂ and oxygen after operation. (7) Avertin may be used with advantage in obstetrics but it is probably inferior to nembutal and chloral as a routine anaesthetic, especially where working single-handed. (8) Practically every surgical condition can be dealt with under avertín. The contra-indications to its use are according to the condition of the patient rather than to the procedure to be adopted, with the exception of operations on the anus and rectum, and tonsillectomy. (9) Tonsillectomy should not be performed under avertin unless a special technique is adopted. (10) Certain conditions of the patient are better treated by avertie than by other means. These are cases of thyroid disease, diabetes, heart cases and all patients of a particularly nervous temperaument. (11) There is a definite .field for the use of avertie in ophthalmology. (12) In the foregoing series of cases the results of Avertin narcosis were uniformly satisfactory (with the exception of the two tonsil cases mentioned above) and post -operative complications were conspicuous by their absence.Though the series is small it covers many different varieties of surgical procedure and the results obtained have been so successful as to warrant the continued use of the drug

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

Investigations and Developments Relevant to a Prototype Laser Interferometric Gravitational Wave Detector

Gravitational waves are travelling distortions in the curvature of space-time. They are a prediction of most relativistic theories of gravity, including general relativity. Their coupling to matter is extremely weak and the only sources likely to be detectable are violent astrophysical events where huge amounts of matter are accelerated very rapidly. Gravitational radiation is quadrupole in nature. It causes a tidal strain in space. With the prototype detector at Glasgow we aim to detect this strain by measuring the differential length change induced in two orthogonal reference arms. This is done using optical interferometry. Chapter 1 is a general introduction to gravitational radiation. The first part is a short review of the sources likely to be detectable by terrestrial interferometric detectors and bar detectors. This is followed by a review of the main features of both resonant bar detectors and interferometric detectors, including a discussion of the main noise sources in both types of detector. The frequency of the illuminating laser needs to be stabilised in interferometric gravitational wave detectors and this is dealt with in the next three chapters. Chapter 2 is a review of the methods used to improve the frequency stability of lasers. It concentrates on continuous, single mode gas lasers such as the argon ion laser used to illuminate the detector at Glasgow. In our prototype detector the laser is frequency locked to one of the 10m long Fabry-Perot cavities. To achieve the desired sensitivity the residual frequency noise must be 2 x 10e7 at 1kHz. Chapter 3 describes a new frequency stabilisation system which acheives this performance. The system is narrow band, as would be required for a large scale detector. It employs two nested servo loops to achieve the desired gain. Chapter 4 is an analysis of the gain and stability of the nested servo loop system described in the previous chapter. The next two chapters concern a 100 hour data run with the prototype detector. Chapter 5 describes the preparation for the run. It includes details of the timing system used and a description of each of the signals that were recorded. Chapter 6 describes the preliminary analysis of the data taken during the run. This analysis was carried out to look at the behaviour of the detector rather than to look for signals from astrophysical sources. The variation of the noise level with time, noise statistics of the data and possible contamination of the data by acoustic and seismic noise were investigated. Chapter 7 starts with a discussion of the results of some calculations of the seismic isolation and thermal noise in some single and double pendulum suspension systems. These show that thermal noise in the lowest stage of the suspension system is likely to be dominant. Measurements of the Q of the suspension of the test masses and of the test masses themselves are then described. Appendix A contains diagrams of the circuits used in the frequency stabilisation system described in chapters 3 and 4, some of their special features are commented on. In appendix B the results of intensity noise measurements in three large frame argon ion lasers are given. These show that the level of high frequency intensity noise varies widely depending on the type of plasma tube used. The measurements were taken in the range 0-7MHz. Appendix C contains two of the data analysis programs