SO2-rich equatorial basins and epeirogeny of Io

Comparison of Io's large scale topography with an SO2 abundance map shows that SO2 is concentrated in equatorial topographic basins. In these basins, about 30 pct. of the surface is covered by SO2 at all elevations above the mean triaxial figure, and SO2 coverage increases with decreasing elevation to as much as 56 pct. at elevations below -1.5 km. The correlation is not good from long 240 to 360 degs where bright areas are covered by red, Pele type plume fallout, and in the polar regions where the topography is poorly known. The histogram of SO2 abundance binned by elevation appears bimodal, with a secondary concentration of SO2 at high elevations, but it is not certain that this is significant. Additional observations suggest that the basins have relatively little higher frequency topographic relief. The distribution of active plumes and hotspots show no obvious correlation with the topography. However, the Pele type plume all erupted from regions higher than the mean figure, and five of the eight Prometheus type plumes are more energetic and are associated with high temperature hotspots, whereas Prometheus type plumes are long lived and require large volatile reservoirs

Digital cartography of Io

A high resolution controlled mosaic of the hemisphere of Io centered on longitude 310 degrees is produced. Digital cartographic techniques were employed. Approximately 80 Voyager 1 clear and blue filter frames were utilized. This mosaic was merged with low-resolution color images. This dataset is compared to the geologic map of this region. Passage of the Voyager spacecraft through the Io plasma torus during acquisition of the highest resolution images exposed the vidicon detectors to ionized radiation, resulting in dark-current buildup on the vidicon. Because the vidicon is scanned from top to bottom, more charge accumulated toward the bottom of the frames, and the additive error increases from top to bottom as a ramp function. This ramp function was removed by using a model. Photometric normalizations were applied using the Minnaert function. An attempt to use Hapke's photometric function revealed that this function does not adequately describe Io's limb darkening at emission angles greater than 80 degrees. In contrast, the Minnaert function accurately describes the limb darkening up to emission angles of about 89 degrees. The improved set of discrete camera angles derived from this effort will be used in conjunction with the space telemetry pointing history file (the IPPS file), corrected on 4 or 12 second intervals to derive a revised time history for the pointing of the Infrared Interferometric Spectrometer (IRIS). For IRIS observations acquired between camera shutterings, the IPPS file can be corrected by linear interpolation, provided that the spacecraft motions were continuous. Image areas corresponding to the fields of view of IRIS spectra acquired between camera shutterings will be extracted from the mosaic to place the IRIS observations and hotspot models into geologic context

The Crystal Structures of Some Mercury (II) Complexes and a Trihalide Compound

Chapter I reviews relevant structural knowledge of compounds containing mercury (II). Much of this material is to be found in a review by Deacon (1963), and will appear in a review by Grdenic (1965)

Disability in young people and adults one year after head injury: prospective cohort study

OBJECTIVE: To determine the frequency of disability in young people and adults admitted to hospital with a head injury and to estimate the annual incidence in the community. DESIGN: Prospective, hospital based cohort study, with one year follow up of sample stratified by coma score. SETTING: Five acute hospitals in Glasgow. SUBJECTS: 2962 patients (aged 14 years or more) with head injury; 549 (71%) of the 769 patients selected for follow up participated. MAIN OUTCOME MEASURES: Glasgow outcome scale and problem orientated questionnaire. RESULTS: Survival with moderate or severe disability was common after mild head injury (47%, 95% confidence interval 42% to 52%) and similar to that after moderate (45%, 35% to 56%) or severe injury (48%, 36% to 60%). By extrapolation from the population identified (90% of whom had mild injuries), it was estimated that annually in Glasgow (population 909 498) 1400 young people and adults are still disabled one year after head injury. CONCLUSION: The incidence of disability in young people and adults admitted with a head injury is higher than expected. This reflects the high rate of sequelae previously unrecognised in the large number of patients admitted to hospital with an apparently mild head injury

Aeroacoustic and aerodynamic performances of an aerofoil subjected to sinusoidal leading edges

This paper presents the preliminary results on the aeroacoustic and aerodynamic performances of a NACA65-(12)10 aerofoil subjected to 12 sinusoidal leading edges. The serration patterns of these leading edges are formed by cutting into the main body of the aerofoil, instead of extending the leading edges. Any of the leading edges, when attached to the main body of the aerofoil, will always result in the same overall chord length. The experiment was mainly performed in an aeroacoustic wind tunnel facility, although a separate aerodynamic type wind tunnel was also used for the force measurements. These sinusoidal leading edges were investigated for their effectiveness in suppressing the laminar instability tonal noise (trailing edge self-noise) and turbulence–leading edge interaction noise. The largest reduction in aerofoil noise tends to associate with the sinusoidal leading edge of the largest amplitude, and smallest wavelength. However, noticeable noise increase at high frequency is also observed for this combination of serration. In terms of the aerodynamic performance, increasing the serration wavelength tends to improve the stall angles, but the lift coefficient at the pre-stall regime is generally lower than that produced by the baseline leading edge. For a sinusoidal leading edge with large serration amplitude, the effect of the reduction in “lift-generating” surface is manifested in the significant reduction of the lift coefficients and lift curve slope. The sinusoidal leading edge that produces the best performance in the post-stall regime belongs to the largest wavelength and smallest amplitude, where the lift coefficients are shown to be better than the baseline leading edge. In conclusion, large amplitude and small wavelength is beneficial for noise reduction, whilst to maintain the aerodynamic lift a small amplitude and large wavelength is preferred