New instrumentation for optical measuring of oxygen in gas or dissolved in liquids.

The optical oxygen sensor is a novel device for the determination of oxygen in gases or dissolved in liquids. It is based on the measurement principle of fluorescence quenching, which is completely different from that of polarographic oxygen sensors (today the most widespread devices of oxygen detection). The new instrument offers features and advantages, which render it not only a realistic alternative, but, for specific applications, make it superior to existing electrochemical methods. The system is based on low-cost semiconductor devices (light-emitting diodes, photodiodes, low-cost analogue and digital components) and new LED-compatible oxygen-sensitive membranes. The flow cell of the instrument may be thermostatted and the sensor can be calibrated by a simple two-point calibration procedure. The optical oxygen sensor is particularly suitable for measuring dissolved oxygen in respirometry, since no oxygen is consumed by the device and the signal is independent of sample flowrate or stirring speed. Typical fields of application are monitoring of oxygen in ground and drinking water, in process control in bioreactors and in breath gas and blood gas analysis.     

Injuries to plants from controlled environment contaminants.

The use of controlled environments is subject to problems from contaminants emitted from materials of the system and from plants. Many contaminants are difficult to identify because injurious dosages are very low, there is a lack of information on what compounds injure plants, because species and cultivars differ greatly in their sensitivity to injury and injury symptoms often are not distinctive. Plastics have been shown to emit many different volatile compounds. The compound, di-butyl phthalate, contained in certain flexible plastics, has been shown to be very toxic to plants. Other injuries have been produced by caulking compounds and bonded screening. Paints have been shown to release xylene that is toxic to plants. Steam for humidification can cause problems because of hydroxylamines and other compounds added to steam used for heating to control fungal growth in return lines. Mercury, from broken thermometers is a particular problem in growth chambers because small quantities can collect in cracks and slowly volatilize to slow growth of plants. Plants themselves release large quantities of volatile hydrocarbons, with ethylene being the commonly recognized chemical that can be damaging when allowed to accumulate. People release large quantities of carbon dioxide which can cause variations in the rate of growth of plants. Contaminant problems can be controlled through filtering of the air or ventilation with make-up air, however the potential for problems is always present and careful testing should be undertaken with the particular species and cultivars being grown insure that there are no toxic agents altering growth in each particular controlled environment being utilized.     

Large-size space laboratory for biological orbit experiments.

The study of space factors on living systems has great interest and long-term experiments during orbital flight will be important tool for increasing our knowledge. Realization of such experiments is limited by constraints of modern space stations. A new technology of large-size space laboratory for biological experiments has been developed on the basis of polymerization techniques. Using this technique there are no limits of form and size of laboratory for a space station that will permit long term experiments on Earth orbit with plants and animals in sufficient volume for creation of closed self-regulating ecological systems. The technology is based on experiments of the behavior of polymer materials in simulated free space conditions during the reaction of polymerization. The influences of space vacuum, sharp temperature changes and space plasma generated by galactic rays and Sun irradiation on chemical reaction were evaluated in their impact on liquid organic materials in laboratory conditions. The results of our study shows, that the chemical reaction is sensitive to such space factors. But we believe that the technology of polymerization could be used for the creation of space biological laboratories in Earth orbit in the near future.     

Protection by WR-2721 and WR-151327 against late effects of gamma rays and neutrons.

Two thiophosphoroate compounds WR-2721 and WR-151327 were assessed for their ability to modify the deleterious effects (life shortening and carcinogenesis) of fission-spectrum neutrons (kerma-weighted mean energy of 0.85 MeV) or gamma rays on B6CF1 hybrid mice. Male and female mice, 200 of each sex per experimental group, were irradiated individually at 110 days of age. Radioprotectors (400 mg/kg of WR-2721 or 580 mg/kg of WR-151327) were administered intraperitoneally 30 min prior to irradiation. Neutron doses were 10 cGy or 40 cGy and gamma ray doses were 206 cGy or 417 cGy. Animals were housed five to a cage; cage locations in the holding rooms were randomized by computer. Animals were checked daily and all deceased animals were necropsied. WR-2721 afforded protection against both neutron- and gamma-ray-induced carcinogenesis and subsequent life shortening. Cumulative survival curves for unirradiated mice of either sex were unaffectecd by protectors. WR-2721 protected irradiated groups against life shortening by approximately 10 cGy of neutrons or 100 cGy of gamma rays. WR-151327 was as effective as WR-2721 against neutron irradiation.     

A large flat panel multifunction display for military and spaceapplications

A flat panel multifunction display (MFD) that offers the size and reliability benefits of liquid crystal display technology while achieving near-CRT display quality is presented. Display generation algorithms that provide exceptional display quality are being implemented in custom VLSI components to minimize MFD size. A high-performance processor converts user-specified display lists to graphics commands used by these components, resulting in high-speed updates of two-dimensional and three-dimensional images. The MFD uses the MIL-STD-1553B data bus for compatibility with virtually all avionics systems. The MFD can generate displays directly from display lists received from the MIL-STD-1553B bus. Complex formats can be stored in the MFD and displayed using parameters from the data bus. The MFD also accepts direct video input and performs special processing on this input to enhance image quality     

Safety testing of lithium ion batteries for navy devices

Lithium ion battery technology is being introduced into power supplies used by our armed forces for a variety of applications. In many cases, the same cells and design parameters that support commercial battery packs are being used in military battery packs. This approach is expected to result in a major decrease in the total life cycle cost of the equipment these batteries support. On June 13, 1991, NAVSEA issued INST9310.1B1, which states that all lithium battery powered equipment must undergo safety evaluation and approval prior to fleet use. This safety program governs a process whereby approvals are issued for lithium batteries to be used in specific equipment on ground facilities, surface combatants, air combatants, and/or submarines. The Naval Ordnance Safety and Security Activity (NOSSA) manages the program. The chief technical advisors are Code 644 at NSWC Carderock Division and Code 609A at NSWC Crane Division. This paper describes three battery designs that incorporate lithium ion technology, and the results of battery safety tests conducted in accordance with navy requirements.     

Chromosome instability of HPRT-mutant subclones induced by ionising radiation of various LET.

The induction of HPRT-mutations and survival of Chinese hamster cells (line B11ii-FAF28, clone 431) were studied after irradiation by 4He and 12C-ions of various LET (20-360 keV/micrometers), produced by the U-200 heavy ion accelerator. The RBE increases with LET up to the maximum at 100-200 keV/micrometers and then decreases. Cytogenetic analysis was performed on the HPRT-mutant subclones selected from unirradiated Chinese hamster V-79 cells and from HPRT-mutant subclones that arose after exposure to gamma-rays, 1 GeV protons and 14N-ions (LET-77 keV/micrometers), produced by the synchrophasotron and the U-400M heavy ion accelerator. Slow growing mutant subclones were observed. The cytogenetic properties of individual clones were highly heterogeneous and chromosome instability was observed in both spontaneous and radiation-induced mutants. Chromosome instability was highest among spontaneous mutants and decreased with increasing LET.     

Controlled solar sail transfers into the near-sun orbits

We present results of numerical simulations of trajectories of a space probe with a flat solar sail which moves from a circular Earth orbit to near-Sun regions. We consider the upper limit of the sail temperature as the basic restriction. We also examine the planar (ecliptic) solar sail transfer with gravity-assist flybys around planets.     

Analysis of radiation risk from alpha particle component of solar particle events.

The solar particle events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and linear energy transfer (LET) spectra in shielding discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.