Calculations of electric currents in Europa

Electrical currents should flow in the Galilean satellite, Europa, because it is located in Jupiter's corotating magnetosphere. The possible magnitudes of these currents are calculated by assuming that Europa is a differentiated body consisting of an outer H2O layer and a silicate core. Two types of models are considered here: one in which the water is completely frozen and a second in which there is an intermediate liquid layer. For the transverse electric mode (eddy currents), the calculated current density in a liquid layer is approximately 10 to the -5/Am. For the transverse magnetic mode (unipolar generator), the calculated current density in the liquid is severely constrained by the ice layer to a range of only 10 to the -10 to -11th power/ Am, for a total H2O thickness of 100 km, provided that neither layer is less than 4 km thick. The current density is less for a completely frozen H2O layer. If transient cracks were to appear in the ice layer, thereby exposing liquid, the calculated current density could rise to a range of 10 to the -6 to 10 to the -5/Am, depending on layer thicknesses, which would require an exposed area of 10 to the -9 to 10 to the -8 of the Europa surface. The corresponding total current of 2.3x10 to the 5th power A could in 1 yr. electrolyze 7x10 to the 5th power kg of water (and more if the cells were in series), and thereby store up to 10 the 8th power J of energy, but it is not clear how electrolysis can take place in the absence of suitable electrodes. Electrical heating would be significant only if the ice-layer thickness were on the order of 1 m, such as might occur if an exposed liquid surface were to freeze over; the heating under this condition could hinder the thickening of the ice layer

Diurnal variations in optical depth at Mars: Observations and interpretations

Viking lander camera images of the Sun were used to compute atmospheric optical depth at two sites over a period of 1 to 1/3 martian years. The complete set of 1044 optical depth determinations is presented in graphical and tabular form. Error estimates are presented in detail. Optical depths in the morning (AM) are generally larger than in the afternoon (PM). The AM-PM differences are ascribed to condensation of water vapor into atmospheric ice aerosols at night and their evaporation in midday. A smoothed time series of these differences shows several seasonal peaks. These are simulated using a one-dimensional radiative convective model which predicts martial atmospheric temperature profiles. A calculation combining these profiles with water vapor measurements from the Mars Atmospheric Water Detector is used to predict when the diurnal variations of water condensation should occur. The model reproduces a majority of the observed peaks and shows the factors influencing the process. Diurnal variation of condensation is shown to peak when the latitude and season combine to warm the atmosphere to the optimum temperature, cool enough to condense vapor at night and warm enough to cause evaporation at midday

Factors governing water condensation in the Martian atmosphere

Modeling results are presented suggesting a diurnal condensation cycle at high altitudes at some seasons and latitudes. In a previous paper, the use of atmospheric optical depth measurements at the Viking lander site to show diurnal variability of water condensation at different seasons of the Mars year was described. Factors influencing the amount of condensation include latitude, season, atmospheric dust content and water vapor content at the observation site. A one-dimensional radiative-convective model is used herein based on the diabatic heating routines under development for the Mars General Circulation Model. The model predicts atmospheric temperature profiles at any latitude, season, time of day and dust load. From these profiles and an estimate of the water vapor, one can estimate the maximum occurring at an early morning hour (AM) and the minimum in the late afternoon (PM). Measured variations in the atmospheric optical density between AM and PM measurements were interpreted as differences in AM and PM condensation

Public Opinion Reform in China

As the People\u27s Republic of China shifts toward a more market-oriented economic system, it has also begun exploring another Western institution: scientific public opinion polling. As Yang Guansan, one of China\u27s leading pollsters, said recently in the Beijing Review: Only five or six years ago, the public opinion poll was considered to be a \u27bourgeois\u27 or \u27capitalist\u27 method of social survey ... Now the taboo has been swept away in the strong tide of reform, which is challenging all of China\u27s traditions, stereotypes and prejudices

Comparison of the mean photospheric magnetic field and the interplanetary magnetic field

Polarity comparison of solar magnetic field and interplanetary magnetic fiel

The Induced Magnetic Field of the Moon: Conductivity Profiles and Inferred Temperature

Electromagnetic induction in the moon driven by fluctuations of the interplanetary magnetic field is used to determine the lunar bulk electrical conductivity. The present data clearly show the north-south and east-west transfer function difference as well as high frequency rollover. The difference is shown to be compatible over the mid-frequency range with a noise source associated with the compression of the local remanent field by solar wind dynamic pressure fluctuations. Models for two, three, and four layer; current layer, double current layer, and core plus current layer moons are generated by inversion of the data using a theory which incorporates higher order multipoles. Core radii conductivities generally are in the range 1200 to 1300 km and 0.001 to 0.003 mhos/m; and for the conducting shell 1500 to 1700 km with 0.0001 to 0.0007 mhos/m with an outer layer taken as nonconducting. Core temperature based on available olivine data is 700 to 1000 C

Synthesis of functionalized membranes for metal capture to tunable separations

Membrane pores functionalized with appropriate macromolecules provide applications ranging from tunable flux and separations at low pressure, toxic metal capture, chemical synthesis, to protein separations. The synthesis may involve direct pore surface grafting of macromolecules or in-situ polymerization in MF type membrane pores. Traditionally, microfiltration membranes have been used for filtration of suspended solids, bacteria, viruses, etc. However, microfiltration membranes (eg, cellulosics, silica, polysulfone, polycarbonate, alumina) can be functionalized with a variety of reagents. Depending on the types of functionalized groups (such as, chain length, charge of groups, biomolecule, etc.) and number of layers, these types of membranes could be used in applications A. Colburn ranging from environmental applications to various organics separations.. In addition, electrostatic self assembly in pores (layer-by-layer, LBL) can also be achieved through alternate adsorption of cationic and anionic polyelectrolytes under convective flow conditions. Non-stoichiometric immobilization of charged multilayers within a confined pore geometry leads to an enhanced volume density of ionizable groups in the membrane phase. For example, the use of polypeptides with helix-coil transitions allows nano-domain interactions in membrane pores for selective environmental separations (using layer-by-layer nano-assembly in pores), and for the capture of various toxic metals. Multilayer assemblies of polyelectrolytes also provide excellent platform for protein/enzyme immobilization by providing reusability and high reactivity. The (1) presentation will include the media synthesis and the role of nano-domain interactions for selective separations, (2) polypeptide/polyeletrolyte assembly in membrane pores for high capacity metal capture to other separation applications, and (3) tunable separations with pH and temperature responsive membrane systems. The author would like to thank NSF KY EPSCoR (Grant no: 1355438) program and by NIH-NIEHS-SRC (Award number: P42ES007380) program for funding various aspects of this work

Unipolar induction in the moon and a lunar limb shock mechanism

Unipolar induction mechanism for electrical field profiles calculation of moon interio

Communications Biophysics

Contains reports on five research projects.National Institutes of Health (Grant 1 P01 GM-14940-01)Joint Services Electronics Program under Contract DA 28-043-AMC-02536(E