ISCCP cloud analysis algorithm intercomparison

The International Satellite Cloud Climatology Project (ISCCP) will provide a uniform global climatology of satellite-measured radiances and derive a climatology of cloud radiative properties from these radiances. For this purpose, a pilot study of cloud analysis algorithms was initiated to define a state-of-the-art algorithm for ISCCP. This study compared the results of applying the nine different algorithms to the same satellite radiance data. The comparison allowed for a sharper understanding of the process of detecting clouds and shows that all algorithms can be improved by better information about clear sky radiance values (essentially equivalent to surface property information) and by better understanding of cloud size distribution variations. The dependence of all methods on cloud size distribution led to selection of an advanced bispectral threshold technique for ISCCP because this method is currently better understood and more developed. Further research on cloud algorithms is clearly suggested by these results.     

A Digital Map Set for the Night Attack Aircraft

There has been much interest recently in applying cartographic digital data bases to advanced avionics systems as a solution to specific problems associated with night attack aircraft missions. The tremendous computer horsepower required to accomplish this task in real-time in an airborne environment is well documented. Hardware implementation of complex algorithms traditionally has produced custom devices which accomplish a specific function on a specific data structure. Historically, this has resulted in powerful but inflexible systems incapable of adapting to the changing requirements of military missions. In an age of evolving technology, these pitfalls must be avoided by incorporating expected changes into the design of digital map systems. If they are made to accommodate a variety of cartographic data bases and allow for programmable manipulation of those bases, this new class of digital map sets can be reconfigured at the software level to meet the changing requirements of aircraft missions. This paper addresses current design concepts for such a map system on a Night Attack aircraft. The focus is on issues concerning the development and handling of existing map data products to meet current system requirements. This system, called the Digital Map Set (DMS), is being designed to accomplish the classical manipulations of Defense Mapping Agency Digital Land Mass System data. Additionally, aeronautical charts, aerial reconnaissance photos, flight plan data, and other two-dimensional bit mapped graphics also are accommodated. Mission requirements relating to the cartographic data bases shall be discussed along with ground support station and airborne system design issues.     

Maglev systems development status

The current status and future potential of Maglev systems is reviewed. Modes of noncontact suspension and propulsion are described, and prototype systems and design concepts are indicated. A number of existing systems are described in more detail     

Infrared detection,review of existing and future devices

I present the current status of arrays of detectors operating in the 1–200 micron range, restricted to mature devices, and two recent concepts of infrared detection which could lead to future developments.     

Crop yield and light/energy efficiency in a closed ecological system: Laboratory Biosphere experiments with wheat and sweet potato.

Two crop growth experiments in the soil-based closed ecological facility, Laboratory Biosphere, were conducted from 2003 to 2004 with candidate space life support crops. Apogee wheat (Utah State University variety) was grown, planted at two densities, 400 and 800 seeds m-2. The lighting regime for the wheat crop was 16 h of light-8 h dark at a total light intensity of around 840 micromoles m-2 s-1 and 48.4 mol m-2 d-1 over 84 days. Average biomass was 1395 g m-2, 16.0 g m-2 d-1 and average seed production was 689 g m-2 and 7.9 g m-2 d-1. The less densely planted side was more productive than the denser planting, with 1634 g m-2 and 18.8 g m-2 d-1 of biomass vs. 1156 g m-2 and 13.3 g m-2 d-1; and a seed harvest of 812.3 g m-2 and 9.3 g m-2 d-1 vs. 566.5 g m-2 and 6.5 g m-2 d-1. Harvest index was 0.49 for the wheat crop. The experiment with sweet potato used TU-82-155 a compact variety developed at Tuskegee University. Light during the sweet potato experiment, on a 18 h on/6 h dark cycle, totaled 5568 total moles of light per square meter in 126 days for the sweet potatoes, or an average of 44.2 mol m-2 d-1. Temperature regime was 28 +/- 3 degrees C day/22 +/- 4 degrees C night. Sweet potato tuber yield was 39.7 kg wet weight, or an average of 7.4 kg m-2, and 7.7 kg dry weight of tubers since dry weight was about 18.6% wet weight. Average per day production was 58.7 g m-2 d-1 wet weight and 11.3 g m-2 d-1. For the wheat, average light efficiency was 0.34 g biomass per mole, and 0.17 g seed per mole. The best area of wheat had an efficiency of light utilization of 0.51 g biomass per mole and 0.22 g seed per mole. For the sweet potato crop, light efficiency per tuber wet weight was 1.33 g mol-1 and 0.34 g dry weight of tuber per mole of light. The best area of tuber production had 1.77 g mol-1 wet weight and 0.34 g mol-1 of light dry weight. The Laboratory Biosphere experiment's light efficiency was somewhat higher than the USU field results but somewhat below greenhouse trials at comparable light levels, and the best portion of the crop at 0.22 g mol-1 was in-between those values. Sweet potato production was overall close to 50% higher than trials using hydroponic methods with TU-82-155 at NASA JSC. Compared to projected yields for the Mars on Earth life support system, these wheat yields were about 15% higher, and the sweet potato yields averaged over 80% higher.     

DNA DSB induced by iron ions in human fibroblasts: LET dependence and shielding efficiency.

This paper reports on DNA DSB induction in human fibroblasts by iron ions of different energies, namely 5, 1 GeV/u, 414 and 115 MeV/u, in absence or presence of different shields (PMMA, Al and Pb). Measure of DNA DSB was performed by calibrated Pulsed Field Gel Electrophoresis using the fragment counting method. The RBE-LET relationships for unshielded and shielded beams were obtained both in terms of dose average LET and of track average LET. Weak dependence on these parameters was observed for DSB induction. The shielding efficiency, evaluated by the ratio between the cross sections for unshielded and shielded beams, depends not only on the shield type and thickness, but also on the beam energy. Protection is only observed at high iron ions energy, especially at 5 GeV/u, where PMMA shield gives higher protection compared to Al or Pb shields of the same thickness expressed in g/cm2.     

Estimates of HZE particle contributions to SPE radiation exposures on interplanetary missions.

Estimates of radiation doses resulting from possible HZE (high energy heavy ion) components of solar particle events (SPEs) are presented for crews of manned interplanetary missions. The calculations assume a model spectrum obtained by folding measured solar flare HZE particle abundances with the measured energy spectra of SPE alpha particles. These hypothetical spectra are then transported through aluminum spacecraft shielding. The results, presented as estimates of absorbed dose and dose equivalent, indicate that HZE components by themselves are not a major concern for crew protection but should be included in any overall risk assessment. The predictions are found to be sensitive to the assumed spectral hardness parameters.     

A review of the hot-wire technique in 2-D compressible flows

In this paper the use of hot-wire anemometers for obtaining turbulence data in two-dimensional compressible flows has been reviewed. Based on the existing experimental results, the methods of extracting different turbulent quantities from the output signal of the hot-wire anemometer in a given flow environment have been described and evaluated. Comparison between the results obtained with the laser Doppler velocimeter (LDV) and the hot-wire anemometer clearly shows that the latter should still be considered as one of the main tools for turbulence research in compressible non-separated turbulent flows not only for its comparable accuracy but also for its much lower cost and ease of operation as compared with the optical methods.