Super-speed centrifugation at sea using a gimballed platform

The use of a super-speed centrifuge at sea for the recovery of suspended solids or interstitial pore fluids requires a stabilizing platform. In this report, we describe a simple platform gimball and magnetic rotor stabilizer that have been fitted to a Sorvall model SS_?3 super-speed centrifuge. In principle, any centrifuge of comparable weight (86 kg) could be easily adapted for use at sea with gimbals of similar design.The magnetic rotor coupler is designed to eliminate rotor precession when the centrifuge is operated at sea. This attachment is particularly useful when the Sorvall SS_?3 (equipped with a conventional rotor) is used to recover interstitial pore fluids.     

Random vectors and spatial analysis by geostatistics for geotechnical applications

Geostatistics is extended to the spatial analysis of vector variables by defining the estimation variance and vector variogram in terms of the magnitude of difference vectors. Many random variables in geotechnology are in vectorial terms rather than scalars, and its structural analysis requires those sample variable interpolations to construct and characterize structural models. A better local estimator will result in greater quality of input models; geostatistics can provide such estimators: kriging estimators. The efficiency of geostatistics for vector variables is demonstrated in a case study of rock joint orientations in geological formations. The positive cross-validation encourages application of geostatistics to spatial analysis of random vectors in geoscience as well as various geotechnical fields including optimum site characterization, rock mechanics for mining and civil structures, cavability analysis of block cavings, petroleum engineering, and hydrologic and hydraulic modelings.     

Venus cloud microphysics

Because sulfuric acid does not wet sulfur, composite drops in the atmosphere of Venus cannot have sulfur “cores,” but must instead have sulfur coats. Both components then communicate with the vapor phase. Drops that are fully coated with sulfur are immune to coalescence; this sets a limit to growth that may explain “Mode 3” particles. The sulfur coating is probably responsible for the anomalously low refractive indices derived from entry-probe nephelometer data. There appears to be about an order of magnitude less elemental sulfur than sulfuric acid in the clouds.     

On the cooling of the moon by solid convection

If a molten, or partially molten, lunar core exists at present, constraints would be placed on the viscosity of the solid mantle and the distribution of radioactive heat sources. Models in which the heat sources have been concentrated near the surface would rapidly solidify if the effective viscosity was equal to, or less than, 10²² cm² s⁻¹. Retention of most of the heat sources throughout the mantle would permit present day solid convection to occur without cooling the core.     

A new interpretation of the Venera 11 spectra of Venus: I. The 0.94-μm water band

Band models for CO₂ and H₂O absorption are described, and used to model the Venera 11 spectra near 1 μm. An effective-path approximation is used to allow for scattering in the clouds. The model has 10 layers and uses 211 CO₂ and 15 H₂O vibrational transitions, at 5 cm^? resolution. Within a factor of 2, a maximum absorption in the 0.94-μm H₂O band just below the clouds, corresponding to 200 ppm by volume, in agreement with V. I. Moroz, N. A. Parfen'ev, and N. F. San'ko (1979, Cosmic Res. 17, 601–614) is found. More accurate band strenghts are needed to model the bottom scale height accurately. The possibility that the 0.94-μm feature is blended with a band of some other molecule has been examined. Ten possible chemical species were examined, with negative results.     

Measuring the accessibility of critical facilities in the presence of hurricane-related roadway closures and an approach for predicting future roadway disruptions

Natural Hazards - Roadway closures magnify the adverse effects of disasters on people since any type of such disruption increases the emergency response travel time (ERTT), which is of central...     

Television photometry: The Mariner 9 experience

Television photometry is compared to conventional techniques. Reduced data from the Mariner 9 cameras should, under optimum conditions, have been accurate to a few percent. However, a combination of unstable camera properties and various unfortunate circumstances (see Appendix A) produced serious nonlinearities (typically 20–40%) and other systematic errors. The means of estimating these errors are described in detail; they lean heavily on the fortuitous presence of a few specks of dust on the faceplate of one vidicon (see Appendix B). Crude corrections, shown in Figs. 2 and 4, will (if applied by hand to “reduced” data) probably improve the photometric quality from that of the Bonner Durchmusterung to nearly that of the Revised Harvard Photometry, for the two most-used filter positions of the A camera. It would be very difficult to improve the photometry further (Appendix C). In view of their low photometric accuracy and detective quantum efficiency (Appendix D), vidicons do not seem likely to replace conventional photography, except for special applications.