On the 14th of June 2001 the Cluster spacecraft made multiple encounters of the dawn- side flank ... more On the 14th of June 2001 the Cluster spacecraft made multiple encounters of the dawn- side flank magnetopause. The characteristics of the plasma population varied between cold dense magnetosheath plasma and warmer more rareified boundary layer plasma on a quasi-periodic basis. The demaraction between the two plasma populations could be readily identifed by gradients in the scalar temperature moment. An analysis of the differences in the observed timings of these gradient maxima indicated that these magnetopause crossings were consistent with a surface wave moving at approximately 100 km/s in an anti-sunward direction with a wavelength of approximately 1.5Re The leading edges of these waves were approximately 45 degrees steeper than the trailing edges consistent with Kelvin-Helmholtz (KH) driven waves.
We are developing and testing a multimedia system for remote operation of transmission electron m... more We are developing and testing a multimedia system for remote operation of transmission electron microscopes and using it to control the Kratos 1500 keV microscope in Berkeley during in situ experiments. Tests, including heating and cooling of specimens on-line under control of the remote operator, have been conducted from Washington (D.C.) and Kansas City. Such in situ experiments subject the specimen under observation to external stimuli (such as heating, cooling, and straining). Full operational control requires adjustments of external stimuli, adjustment of specimen position and orientation, and manipulation of microscope controls such as illumination, magnification, and focus. In conventional (non-remote) operation, a local operator makes adjustments in response to the image from the microscope; in remote mode, current wide area networks cannot offer the real-time delivery guarantees required for the adjustments necessary for dynamic in situ studies. We have designed a system that minimizes the real-time delivery requirement by incorporating local automation of stage control and microscope focus. The system corrects for specimen drift (often severe during rapid heating and cooling) by controlling stage movement with optical flow fields; it provides automatic focus using wavelet coefficients with Daubechies kernels. Wavelet transforms are also used for image compression. During remote operation, we obtained 640x480-pixel images at a rate of 0.6 fps, providing effective operator control of the microscope and the experiment.
... In order to begin to answer that question, we need to look still further back: back before th... more ... In order to begin to answer that question, we need to look still further back: back before the brief affair between Carmen Sternwood and Owen Taylor, before Chandler and before the invention of hard-boiled detective fiction, back to the sources of narrative film. ...
A method is described to directly measure mean spiral diameter in a magnetically confined electro... more A method is described to directly measure mean spiral diameter in a magnetically confined electron beam. In collision experiments, spiraling affects polarization measurements and effective path length assessment; and in experiments using colliding beams, the collision energy or energy spread can be significantly altered. The technique described here allows experimental correction for these effects. Magnitudes of transverse velocities from various
In-situ instrumentation for proposed future solar and heliophysics missions close to the sun, e.g... more In-situ instrumentation for proposed future solar and heliophysics missions close to the sun, e.g., ESA's Solar Orbiter and NASA's Solar Sentinels, have challenging requirements. Notably, the two major challenges are the large dynamic range required to be covered and the mission lifetime. For example, the proposed orbit of Solar Orbiter ranges from 0.22 AU to 1.39 AU, resulting in up to 2 orders of magnitude change in flux that the instrument is required to handle, with a proposed mission life of greater than 10 years. We present details of a prototype instrument that is currently being developed to address some of these challenges. The instrument is a conventional "top-hat" type symmetric quadrispheric analyzer with a pair of electrostatic deflector plates designed to accept approximately +/- 40° in elevation. Optimization of the geometry of the deflector plates will be discussed and preliminary results of the performance of the instrument will be presented. In addition, some of the other techniques and strategies that will be required to deliver the necessary performance will also be discussed.
Pmeridge Press, April 1982, 300 pp, ISBN 0-906674-19-0 The text comprises ten chapters contribute... more Pmeridge Press, April 1982, 300 pp, ISBN 0-906674-19-0 The text comprises ten chapters contributed by recogmsed scientists and engineers working on the numerical analysis of nonlinear continua. Techmques are discussed for the efficient solution of nonlinear problems under quaslstatlc, slow transient and dynamic condltmns. As well as equation solutmn methods, processes are discussed for load incrementatmn m the vxcmlty of limit points. Attention is also focused on the stabdlty characteristics of tranment solution schemes. Nonhnear behawours arising from elastoplasticity, elasto-wscoplastlclty and geometric nonlinear effects are consxdered either together or separately.
Small amounts of oil that can persist for decades in the intertidal zone of coarse-sediment beach... more Small amounts of oil that can persist for decades in the intertidal zone of coarse-sediment beaches have been documented in a few well-studied cases. Oil that survives attenuation over the short-term (weeks to months) will persist until there is a change in the environmental conditions, as might occur where there is a seasonal storm-wave climate or as a beach undergoes long-term (erosional) changes. Oil residues can persist on the beach surface as tar mats, asphalt-like pavements, or as veneers on sediment particles or hard surfaces. Subsurface oil residues can persist in similar forms or as fill or partial fill of the pore spaces between coarse-sediment particles. Oil penetrates until it reaches fine-grained sediment, the water table, bedrock, or other penetration-limiting layers. Amounts of persistent oil are very small fractions of the volumes that were originally stranded and these protected residues can continue to biodegrade as they become thinner and more discontinuous.
Aims A National Screening Programme for diabetic eye disease in the UK is in development. We prop... more Aims A National Screening Programme for diabetic eye disease in the UK is in development. We propose a grading and early disease management protocol to detect sight-threatening diabetic retinopathy and any retinopathy, which will allow precise quality assurance at all steps while minimizing false-positive referral to the hospital eye service.
This excellent volume provides a comprehensive review of the recent research in non-linear comput... more This excellent volume provides a comprehensive review of the recent research in non-linear computational mechanics. The reviewer believes that anyone desiring to seek a numerical solution of non-linear mechanics problems will benefit immensely by studying the book. Each one of the ten chapters in the book has been written by an eminent researcher. The authors have summarised the current state of the knowledge in their respective areas of research and have provided an extensive list of references. Some prior understanding of the basics of linear elasticity, plasticity and the finite element method has been presumed of the reader.
This excellent volume provides a comprehensive review of the recent research in non-linear comput... more This excellent volume provides a comprehensive review of the recent research in non-linear computational mechanics. The reviewer believes that anyone desiring to seek a numerical solution of non-linear mechanics problems will benefit immensely by studying the book. Each one of the ten chapters in the book has been written by an eminent researcher. The authors have summarised the current state of the knowledge in their respective areas of research and have provided an extensive list of references. Some prior understanding of the basics of linear elasticity, plasticity and the finite element method has been presumed of the reader.
On the 14th of June 2001 the Cluster spacecraft made multiple encounters of the dawn- side flank ... more On the 14th of June 2001 the Cluster spacecraft made multiple encounters of the dawn- side flank magnetopause. The characteristics of the plasma population varied between cold dense magnetosheath plasma and warmer more rareified boundary layer plasma on a quasi-periodic basis. The demaraction between the two plasma populations could be readily identifed by gradients in the scalar temperature moment. An analysis of the differences in the observed timings of these gradient maxima indicated that these magnetopause crossings were consistent with a surface wave moving at approximately 100 km/s in an anti-sunward direction with a wavelength of approximately 1.5Re The leading edges of these waves were approximately 45 degrees steeper than the trailing edges consistent with Kelvin-Helmholtz (KH) driven waves.
We are developing and testing a multimedia system for remote operation of transmission electron m... more We are developing and testing a multimedia system for remote operation of transmission electron microscopes and using it to control the Kratos 1500 keV microscope in Berkeley during in situ experiments. Tests, including heating and cooling of specimens on-line under control of the remote operator, have been conducted from Washington (D.C.) and Kansas City. Such in situ experiments subject the specimen under observation to external stimuli (such as heating, cooling, and straining). Full operational control requires adjustments of external stimuli, adjustment of specimen position and orientation, and manipulation of microscope controls such as illumination, magnification, and focus. In conventional (non-remote) operation, a local operator makes adjustments in response to the image from the microscope; in remote mode, current wide area networks cannot offer the real-time delivery guarantees required for the adjustments necessary for dynamic in situ studies. We have designed a system that minimizes the real-time delivery requirement by incorporating local automation of stage control and microscope focus. The system corrects for specimen drift (often severe during rapid heating and cooling) by controlling stage movement with optical flow fields; it provides automatic focus using wavelet coefficients with Daubechies kernels. Wavelet transforms are also used for image compression. During remote operation, we obtained 640x480-pixel images at a rate of 0.6 fps, providing effective operator control of the microscope and the experiment.
... In order to begin to answer that question, we need to look still further back: back before th... more ... In order to begin to answer that question, we need to look still further back: back before the brief affair between Carmen Sternwood and Owen Taylor, before Chandler and before the invention of hard-boiled detective fiction, back to the sources of narrative film. ...
A method is described to directly measure mean spiral diameter in a magnetically confined electro... more A method is described to directly measure mean spiral diameter in a magnetically confined electron beam. In collision experiments, spiraling affects polarization measurements and effective path length assessment; and in experiments using colliding beams, the collision energy or energy spread can be significantly altered. The technique described here allows experimental correction for these effects. Magnitudes of transverse velocities from various
In-situ instrumentation for proposed future solar and heliophysics missions close to the sun, e.g... more In-situ instrumentation for proposed future solar and heliophysics missions close to the sun, e.g., ESA's Solar Orbiter and NASA's Solar Sentinels, have challenging requirements. Notably, the two major challenges are the large dynamic range required to be covered and the mission lifetime. For example, the proposed orbit of Solar Orbiter ranges from 0.22 AU to 1.39 AU, resulting in up to 2 orders of magnitude change in flux that the instrument is required to handle, with a proposed mission life of greater than 10 years. We present details of a prototype instrument that is currently being developed to address some of these challenges. The instrument is a conventional "top-hat" type symmetric quadrispheric analyzer with a pair of electrostatic deflector plates designed to accept approximately +/- 40° in elevation. Optimization of the geometry of the deflector plates will be discussed and preliminary results of the performance of the instrument will be presented. In addition, some of the other techniques and strategies that will be required to deliver the necessary performance will also be discussed.
Pmeridge Press, April 1982, 300 pp, ISBN 0-906674-19-0 The text comprises ten chapters contribute... more Pmeridge Press, April 1982, 300 pp, ISBN 0-906674-19-0 The text comprises ten chapters contributed by recogmsed scientists and engineers working on the numerical analysis of nonlinear continua. Techmques are discussed for the efficient solution of nonlinear problems under quaslstatlc, slow transient and dynamic condltmns. As well as equation solutmn methods, processes are discussed for load incrementatmn m the vxcmlty of limit points. Attention is also focused on the stabdlty characteristics of tranment solution schemes. Nonhnear behawours arising from elastoplasticity, elasto-wscoplastlclty and geometric nonlinear effects are consxdered either together or separately.
Small amounts of oil that can persist for decades in the intertidal zone of coarse-sediment beach... more Small amounts of oil that can persist for decades in the intertidal zone of coarse-sediment beaches have been documented in a few well-studied cases. Oil that survives attenuation over the short-term (weeks to months) will persist until there is a change in the environmental conditions, as might occur where there is a seasonal storm-wave climate or as a beach undergoes long-term (erosional) changes. Oil residues can persist on the beach surface as tar mats, asphalt-like pavements, or as veneers on sediment particles or hard surfaces. Subsurface oil residues can persist in similar forms or as fill or partial fill of the pore spaces between coarse-sediment particles. Oil penetrates until it reaches fine-grained sediment, the water table, bedrock, or other penetration-limiting layers. Amounts of persistent oil are very small fractions of the volumes that were originally stranded and these protected residues can continue to biodegrade as they become thinner and more discontinuous.
Aims A National Screening Programme for diabetic eye disease in the UK is in development. We prop... more Aims A National Screening Programme for diabetic eye disease in the UK is in development. We propose a grading and early disease management protocol to detect sight-threatening diabetic retinopathy and any retinopathy, which will allow precise quality assurance at all steps while minimizing false-positive referral to the hospital eye service.
This excellent volume provides a comprehensive review of the recent research in non-linear comput... more This excellent volume provides a comprehensive review of the recent research in non-linear computational mechanics. The reviewer believes that anyone desiring to seek a numerical solution of non-linear mechanics problems will benefit immensely by studying the book. Each one of the ten chapters in the book has been written by an eminent researcher. The authors have summarised the current state of the knowledge in their respective areas of research and have provided an extensive list of references. Some prior understanding of the basics of linear elasticity, plasticity and the finite element method has been presumed of the reader.
This excellent volume provides a comprehensive review of the recent research in non-linear comput... more This excellent volume provides a comprehensive review of the recent research in non-linear computational mechanics. The reviewer believes that anyone desiring to seek a numerical solution of non-linear mechanics problems will benefit immensely by studying the book. Each one of the ten chapters in the book has been written by an eminent researcher. The authors have summarised the current state of the knowledge in their respective areas of research and have provided an extensive list of references. Some prior understanding of the basics of linear elasticity, plasticity and the finite element method has been presumed of the reader.
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