Development of a prototype automatic controller for liquid cooling garment inlet temperature

The development of a computer control of a liquid cooled garment (LCG) inlet temperature is descirbed. An adaptive model of the LCG is used to predict the heat-removal rates for various inlet temperatures. An experimental system that contains a microcomputer was constructed. The LCG inlet and outlet temperatures and the heat exchanger outlet temperature form the inputs to the computer. The adaptive model prediction method of control is successful during tests where the inlet temperature is automatically chosen by the computer. It is concluded that the program can be implemented in a microprocessor of a size that is practical for a life support back-pack

Issues in providing a reliable multicast facility

Issues involved in point-to-multipoint communication are presented and the literature for proposed solutions and approaches surveyed. Particular attention is focused on the ideas and implementations that align with the requirements of the environment of interest. The attributes of multicast receiver groups that might lead to useful classifications, what the functionality of a management scheme should be, and how the group management module can be implemented are examined. The services that multicasting facilities can offer are presented, followed by mechanisms within the communications protocol that implements these services. The metrics of interest when evaluating a reliable multicast facility are identified and applied to four transport layer protocols that incorporate reliable multicast

Relationship between clear-sky atmospheric greenhouse effect and deep convection during the Central Equatorial Pacific Experiment: Model calculations and satellite observations

This study investigates the relation between tropical convection and the atmospheric greenhouse effect using data collected during the Central Equatorial Pacific Experiment (CEPEX). We present calculations of total clear-sky greenhouse effect and its partitioning between the lower, middle, and upper troposphere using high-quality balloon soundings of temperature and humidity as input to a radiative transfer model. The soundings were taken from a ship every 6 hours from March 7 to 20, 1993, in the central Pacific. We examine the influence on atmospheric greenhouse effect due to changes in humidity and lapse rate and investigate the relationship between atmospheric greenhouse effect, water vapor, and deep convection. Our observations indicate that periods of active or suppressed convection with timescales of the order of days can produce large spatial gradients in clear-sky atmospheric greenhouse trapping in warm, climatologically convective regions. While the sea surface temperature (SST) decreased by 2 K from west to east, temperatures above 850 mbar showed considerably less variation. Accordingly, lapse rate changes occurred primarily in the boundary layer and such changes account for 80% of the gradient in boundary layer greenhouse effect. The column-integrated water vapor content from the surface to 850 mbar was nearly constant in each of the regimes. Conversely, large variations in column-integrated water vapor above 850 mbar and particularly above 500 mbar account for nearly all the gradient in the greenhouse effect in the middle and upper troposphere. Coincident outgoing longwave radiation (OLR) analyses derived from satellite observations show active deep convection in areas with high clear-sky greenhouse trapping and upper level moisture and generally clear, suppressed conditions elsewhere. In addition, the surface net flux and outgoing flux emitted to space decreased with increased SST. The reduced cooling of the ocean-atmosphere system is consistent with a supergreenhouse effect operating in regions of deep convection

Pulsed Doppler lidar for the detection of turbulence in clear air

A pulsed C02 Doppler lidar system is described and demonstration tests in ground-based and airborne flight operations are discussed. As a ground-based system, it can detect wind shears in thunderstorm gust fronts to a range of 6 km. When in the airborne configuration, the lidar can detect clear air turbulence in advance of the aircraft encountering clear air turbulence. The data provided by the lidar included turbulence location and intensity with intensity being indicated by the measured spectral width which is proportional to the wind gust velocity

Failure of the ERBE scanner instrument aboard NOAA 10 spacecraft and results of failure analysis

The Earth Radiation Budget Experiment (ERBE) scanner instrument on the NOAA 10 spacecraft malfunctioned on May 22, 1989, after more than 4 years of in-flight operation. After the failure, all instrument operational mode commands were tested and the resulting data analyzed. Details of the tests and analysis of output data are discussed therein. The radiometric and housekeeping data appear to be valid. However, the instrument will not correctly execute operational scan mode commands or the preprogrammed calibration sequences. The data indicate the problem is the result of a failure in the internal address decoding circuity in one of the ROM (read only memory) chips of the instrument computer

Local Ferroelectricity in SrTiO_3 Thin Films

The temperature-dependent polarization of SrTiO_3 thin films is investigated using confocal scanning optical microscopy. A homogeneous out-of-plane and inhomogeneous in-plane ferroelectric phase are identified from images of the linear electrooptic response. Both hysteretic and non-hysteretic behavior are observed under a dc bias field. Unlike classical transitions in bulk ferroelectrics, local ferroelectricity is observed at temperatures far above the dielectric permittivity maximum. The results demonstrate the utility of local probe experiments in understanding inhomogeneous ferroelectrics.Comment: 8 pages, 3 figures, accepted for publication in PR

Photonic excess noise and wave localization

This is a theory for the effect of localization on the super-Poissonian noise of radiation propagating through an absorbing disordered waveguide. Localization suppresses both the mean photon current I and the noise power P, but the Fano factor P/I is found to remain unaffected. For strong absorption the Fano factor has the universal value 1+3f/2 (with f the Bose-Einstein function), regardless of whether the waveguide is long or short compared to the localization length.Comment: 3 pages including 3 figure