Solar X-ray studies

The hard X-ray component in the impulsive phase of solar flares is reported. Observations from OGO-5 OSO-7 show no center-to-limb effect of soft X-ray flare. These soft events were plotted separately as a function of solar longitude

The triggering and subsequent development of a solar flare

High temporal and spatial resolution solar X-ray pictures of a flare at 1827 UT on 5 September 1973 were taken with the S-056 telescope on the Apollo telescope mount. Photographs taken at 9 sec intervals allow detailed information to be obtained about the site of the energy release, as well as about the evolution of the flare itself. Observations suggest that the flare occurred in an entire arcade of loops rather than in any single loop. Sequential brightening of different X-ray features indicates that some excitation moved perpendicular to the magnetic field of the arcade at velocities of 180 to 280 km/sec. The most intense X-ray features were located in places where the magnetic field composing the arcade had a small radius of curvature with horizontal field gradients higher than the surroundings region and where the axis of the arcade changed direction. It was felt that the arcade geometry strongly influenced the propagation of the triggering disturbance, as well as the storage and site of the subsequent deposition of energy. A magnetosonic wave is suggested as the propagating mechanism triggering instabilities that may have existed in the preflare structure

Investigation of the deformation of in-vessel components of a nuclear fusion experiment using optical strain sensors

A fibre-optic, EM-insensitive measurement for the deformation of in-vessel components has successfully been installed and operated at the nuclear fusion experiment ASDEX Upgrade. The sensors were tested for their neutron tolerance and vacuum compatibility. Installation was done by copper-steel laser beam welding. Measurements of in-service oscillations due to all three existing types of load cases show good agreement with theory and simulations. A fatigue lifetime assessment was performed

Identification of the hard X-ray pulse in the flare of September 11-12, 1968

A hard X-ray pulse in the 11–12 September 1968 flare is identified with the formation of a brilliant kernel. Each stage in the X-ray event corresponds to a definite phase in flare development

Identification of the hard X-ray pulse in the flare of September 11-12, 1968

A hard X-ray pulse in the 11–12 September 1968 flare is identified with the formation of a brilliant kernel. Each stage in the X-ray event corresponds to a definite phase in flare development

Influence of Structural Redundancy on Fatigue Life of Offshore Wind Turbine Jacket Structures

The concept of structural redundancy is implemented in the fatigue analysis of an offshore wind turbine jacket structure. The analyzed jacket is a real life example. Time domain analyses are performed for the most representative design load case. The uni-directional and multidirectional simulations of the offshore wind turbine system are carried out using a coupling of the aero-elastic code and the finite element code. Fatigue analyses are performed using hot spot stress approach and Miner's rule. Comparative studies show that considering structural redundancy leads to expanded fatigue life of the offshore wind turbine jacket structures. © 2017 ISOPEEC/Horizon202

Contact lens field examiner

Low vision aids have not been successfully prescribed for many patients with peripheral visual field loss. In this experiment, visual field and visual acuity measurements for eighteen subjects with artificially restricted fields were made with and without two contact lens field expanders. The calculated visual efficiency was significantly improved with these devices which led the experimenters to believe that the potential of this device is very good for being a useful low vision aid

Observations of the structure and evolution of solar flares with a soft X-ray telescope

Soft X ray flare events were observed with the S-056 X-ray telescope that was part of the ATM complement of instruments aboard SKYLAB. Analyses of these data are reported. The observations are summarized and a detailed discussion of the X-ray flare structures is presented. The data indicated that soft X-ray emitted by a flare come primarily from an intense well-defined core surrounded by a region of fainter, more diffuse emission. An analysis of flare evolution indicates evidence for preliminary heating and energy release prior to the main phase of the flare. Core features are found to be remarkably stable and retain their shape throughout a flare. Most changes in the overall configuration seem to be result of the appearance, disappearance or change in brightness of individual features, rather than the restructuring or reorientation of these features. Brief comparisons with several theories are presented

Modeling of offshore wind turbines with braced support structures

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Ein Fall von Melaena neonatorum, hervorgerufen durch Blutung aus angeborenen Phlebektasien des Oesophagus

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