The giant planets and their satellites: Report on the Cospar Symposium,Ottawa, Canada,May 18–21, 1982

A $\text{Symposium on the Giant Planets and Their Satellites}$ was presented in conjunction with the Twenty-fourth Plenary Meeting of the Committee on Space Research. This paper summarizes the talks presented and places the remaining papers of this volume in context.     

Thin-film Li-LiMn2O4 batteries

Thin-film rechargeable Li-LiMn₂O₄ batteries have been fabricated and characterized. Following deposition by electron beam evaporation of LiMn₂O₄, the amorphous as-deposited cathode films 1 cm² in area by 0.3to 4-μm thick were annealed at 700°C to 800°C in oxygen in order to form the crystalline spinet phase. The specific capacity of the cells between 4.5 V to 3.8 V ranged from 50 μAh/mg to 120 μAh/mg. When cycled over this range, the batteries exhibited excellent secondary performance with capacity losses as low as 0.001% per cycle. On charging to 5.3 V, a plateau with a median voltage of 5.1 V was observed. The total charge extracted between 3.8 V to 5.3 V corresponded to about 1 Li/Mn₂ O₄     

Heavy ion action on yeast cells: inhibition of ribosomal-RNA synthesis, loss of colony forming ability and induction of mutants.

The action of heavy ions (Ar to U) accelerated to specific energies up to about 10 MeV/u (u=atomic mass unit) on different functions of yeast cells was studied. Ribosomal-RNA synthesis is inhibited according to a single-hit mechanism. Inactivation cross-sections were linearly related to the ratio of the squares of the effective charge Z* and the velocity of the ions. It is concluded from the analysis that the range of the most energetic delta-electrons is larger than previously assumed. There is no such dependence for survival and induction of mutants. In both cases cross-sections increase with the ion's specific-energy indicating an important contribution of long-range delta-electrons. The analysis shows that diploid yeast is not killed by a single-hit mechanism even by very heavy ions if the track width is too small. The relative importance of the penumbral region is even more pronounced with the more sensitive strains.     

Utility of landsat data in mineral exploration — a case study from Orissa,India

The utility of Landsat data in geosciences has been established beyond doubt. In this paper utility of Landsat data in mineral exploration has been highlighted.The geologic and geomorphic interpretation of Landsat data brought out two very significant and characteristic features in scene 152-046 in the southern part of Orissa. One was distinct tonal anomaly and other was occurance of flat planated surface devoid of vegetation and drainage on top of hills. This when checked on ground at Gandhmardan was found to be bauxite bearing lateritic plateau. When this known information was extrapolated over other regions in scenes 151-046 and 152-046, all other bauxitic — lateritic plateaus were picked up very easily on Landsat imagery.The information was further extrapolated in the southern scene No.152-047 where without doing much detailed geologic and geomorphic interpretation almost all other bauxitic — lateritic bodies occuring in the region were picked up. This proves the utility of Landsat data in mineral exploration.Moreover delineation of extent of such bodies could be done very accurately on Landsat imagery thus saving considerable time in the exploration programme.     

The Magellan project

Magellan is one of the future space projects being studied by the European Space Agency. The aim is to provide high resolution (λ/Δλ ≥ 2.5 × 10⁴) spectra in the far and extreme UV (between 500 and 1550 Å) of faint galactic and extragalactic objects (V ≤ 16^m). The instrument consists of a mechanical collimator, a concave holographic grating and a bidimensional photon-counting detector. A low resolution mode (λ/Δλ ≥ 10³) will provide spectra of objects as faint as 18^m.5. Magellan is planned as an observatory, operated in real time, and allowing interaction with the observer.     

Causes of aircraft electrical failures

The results of a survey of data on failures of aircraft electronic and electrical components that was conducted to identify problematic components are reported. The motivation for the work was to determine priorities for future work on the development of accident investigation techniques for aircraft electrical components. The primary source of data was the Airforce Mishap Database, which is maintained by the Directorate of Aerospace Safety at Norton Air Force Base. Published data from the Air Force Avionics Integrity Program (AVIP) and Hughes Aircraft were also reviewed. Statistical data from these three sources are presented. Two major conclusions are that problems with interconnections are major contributors to aircraft electrical equipment failures, and that environmental factors, especially corrosion, are significant contributors to connector problems     

Radiation transmission in adverse weather

A simplified practical approach to determining the effects of weather on the transmission of radiation at visible, infrared (IR), and millimetre (mm) wavelengths, with particular reference to the aircraft landing problem, is outlined. Passive landing systems are studied. Landing categories related to visibility are defined. An extinction coefficient used to relate the effect of the atmosphere on the radiation detected by the human eye (or an imaging sensor onboard the aircraft) to the landing category and the calculation of this coefficient are discussed. The approach makes use of data from openly available literature. Results have been found useful in indicating the effects of adverse weather on imaging sensor performance for an enhanced vision aircraft-mounted landing system. As an example of the technique, the method of determining the extinction coefficients in fog for infrared radiation is outlined     

Development of B-1 antenna measurement test bed

The establishment of a B-1 test bed is chronicled from identification of the requirement to the initial measurements program. Disassembly, modification, and reassembly of the airframe are covered. Future modifications and measurements are previewed. The facilities at which the B-1 test bed is located are briefly discussed     

High performance magnetostrictive actuators

The application of magnetostriction in the design of a hybrid, electromechanical/hydraulic high-performance linear (large force and stroke) and/or rotational (large moment and angle) actuator is considered. The design concept combines the high power density of actuation possible with magnetostriction (approaching 0.1 HP/cm³ of the magnetostrictive material assuming 3 kHz excitation frequency) and the design flexibility of hydraulics. The objective of the research described was to validate the concept theoretically and to study alternatives and improvements. The system, as currently envisioned, offers very small packaging volume (approximately an order of magnitude smaller than conventional electromechanical systems), flexible packaging (relative location of the major system components is not critical), and easy control (precise control of actuation speed, quick reverse time, and inherent position lockup). The major technical problems associated with the design are outlined, and results of a computer simulation of a prototype actuator are presented     

Energy and charge localization in irradiated DNA.

The relation between the site of energy deposition and the site of its biological action is an important question in radiobiology. Even at 77 degrees K, evidence is clear that these two sites must be separated since energy deposition is random but specific products are formed. Several processes that may contribute to this separation are: 1) hole migration and stabilization through deprotonation to give neutral oxidation product radicals; 2) electron trapping and transfer to form specific radical anions, possibly followed by protonation to give neutral reduction product radicals; and 3) recombination of spatially separated charges or radicals. These microscopic processes will be reviewed critically in an analysis using electron paramagnetic resonance spectroscopy (EPR) evidence for and against long-range transfer of energy and/or charge in frozen, hydrated DNA.