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     

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     

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     

A target cueing and tracking system (TCATS) for smart videoprocessing

A smart system that uses state-of-the-art image processing techniques to detect and track targets moving in video or infrared imagery is presented. It is a general-purpose system that was developed to be independent of the application and the user interface. TCATS has successfully demonstrated a high detection capability and the ability to ignore exterior environmental conditions, such as cloud shadows moving through the scene, snow, blowing dust, rain and moderate camera motion. TCATS can handle many targets and retain the identity of each object from one frame to the next. Special rugged hardware has been developed to reduce the size, cost, and power consumption and to increase the processing rate, reliability, and environmental operating capability of the system. TCATS can be incorporated into an existing video assessment system without a major cost outlay intruder. The TCATS algorithms, custom-developed hardware, and preliminary field test results are described     

Prebiotic oligodeoxynucleotide synthesis in a cyclic evaporating system at low temperatures.

Deoxynucleoside 5'-monophosphates were condensed by cyanamide or by l-ethyl-3-(3-dimethylaminopropyl) carbodiimide in the presence of ammonium chloride at 0 degree, 37 degrees or 60 degrees C through several cycles of evaporation to dryness with replenishment of all reactants at each cycle. We found that at 37 degrees or 60 degrees cyanamide gives distinctly more high molecular weight material than does carbodiimide. Indeed, the yield of condensed products for the cyanamide reaction (dimers and higher oligomers) was found to be between 60 percent and 80 percent. The molecular weight distribution of the product shifts to higher molecular weights as cycling continues at 37 degrees or 60 degrees for both condensing agents. The water soluble carbodiimide gives higher yields of low molecular weight product but much lower yields of the higher molecular weight products. At 0 degree yields of high molecular weight product were low for both condensing agents. Results of characterization of the products demonstrate the synthesis of oligodeoxynucleotides including tetramers, with 3'-5' phosphodiester linkages.     

Visual thematic mapping from Landsat and collateral data in support of mineral development

Over the past ten years, the authors and their associates have used Landsat images and collateral data to prepare visual thematic maps. The data are used in a projection-compositor (Procom) system that enlarges Landsat images and other data to scales as great as 1:15 000. Revisions of existing maps for simple themes (e.g. topographic maps) can be completed quickly, accurately and inexpensively. Complex themes, such as geological formations and structures, can be mapped through the optical merging of collateral data sets (e.g. Landsat, geophysics, geology) at a common scale. Such mapping has led to the recognition of a non-parallactic means of obtaining whole image stereo-models with large vertical exaggerations using Landsat images.     

A global HF telecommand system for long duration balloon flights

An HF telecommand system for the control of long duration balloon flights at any point on the globe is described. The system proposed consists of a network of low-power transmitters operating at the same carrier frequency. The choice of transmitter frequency, power and location are presented. Control of the transmitters may be performed remotely by means of the public switched telephone network; an assessment of the error-rate in the system as a whole is given.     

Evaluation of light emitting diode characteristics for a space-based plant irradiation source.

Light emitting diodes (LEDs) are a promising irradiation source for plant growth in space. Improved semiconductor technology has yielded LED devices fabricated with gallium aluminum arsenide (GaAlAs) chips which have a high efficiency for converting electrical energy to photosynthetically active radiation. Specific GaAlAs LEDs are available that emit radiation with a peak wavelength near the spectral peak of maximum quantum action for photosynthesis. The electrical conversion efficiency of installed systems (micromole s-1 of photosynthetic photons per watt) of high output LEDs can be within 10% of that for high pressure sodium lamps. Output of individual LEDs were found to vary by as much as 55% from the average of the lot. LED ratings, in mcd (luminous intensity per solid angle), were found to be proportional to total photon output only for devices with the same dispersion angle and spectral peak. Increasing current through the LED increased output but also increased temperature with a consequent decrease in electrical conversion efficiency. A photosynthetic photon flux as high as 900 micromoles m-2 s-1 has been produced on surfaces using arrays with LEDs mounted 7.6 mm apart, operating as a current of 50 mA device-1 and at an installed density of approximately 17,200 lamps m-2 of irradiated area. Advantages of LEDs over other electric light sources for use in space systems include long life, minimal mass and volume and being a solid state device.     

Computer analysis of the lineaments of Nepal

Various information has been obtained by computer analysis of the lineaments of Nepal. The data were carefully studied and correlated to establish the relationships of lineaments with geological units, structure, mineralization, etc. The lineament map of Nepal was prepared during 1977–1978; the lineament data were digitized in 1982—using a Hewlett Packard system 45 desktop computer—separated by area (east, central and west Nepal) and also according to geological units. By trial and error and using all variables, the different preferred orientation classes were identified for east, central and west Nepal. Lineaments were grouped according to length into less than 10 km, 10–20 km, 20–30 km and more than 30 km, for the entire country and also for major geological units, i.e., Siwalik (sub-Himalaya), Lesser Himalaya (midlands) and Higher Himalaya. Various rose diagrams and histograms showing frequency and lengths of lineaments were plotted for the different geological units and the different sectors. Lineaments associated with granites of major subdivisions were plotted separately and analysed.     

Synoptic observations of coronal transients and their interplanetary consequences

A small coronagraph has been placed in orbit to monitor the sun's outer corona from 2.5 to 10.0 solar radii, and five years of nearly continuous synoptic observations have now been completed. Rapid and sensitive image processing techniques have been developed to screen the data for transient phenomena, particularly coronal mass ejections (CMEs). About 50,000 coronal images have been examined, out of a five-year total of 68,000, and a standardized listing of more than 1,200 coronal transients for the period 1979–1982 has been prepared. These data have been analysed in the light of other available information, particularly on conditions in the interplanetary plasma. The dynamical characteristics of the active corona, as they are beginning to emerge from the data, are presented. We find that coronal mass ejections exercise significant influence on the interplanetary solar wind. They are the source of disturbances that are frequent and energetic, that tend to be somewhat focussed, that often reach shock intensity, and that propagate to large heliocentric distances, sometimes causing major geomagnetic storms.