Helicopter technology benefits and needs. Volume 2: Appendices

Vehicle design, avionics and flight systems; safety and reliability; navigation, guidance and flight control; propulsion; auxiliary systems; human factors; and monitoring and diagnostic systems are the technology areas involved in solving operational and technical problems related to the use of helicopters. Tables show the problems encountered and the proposed research and technology for helicopter use for search and rescue; emergency medical services; law enforcement; environmental control; fire fighting; and resource management

Creep of plasma sprayed zirconia

Specimens of plasma-sprayed zirconia thermal barrier coatings with three different porosities and different initial particle sizes were deformed in compression at initial loads of 1000, 2000, and 3500 psi and temperatures of 1100 C, 1250 C, and 1400 C. The coatings were stabilized with lime, magnesia, and two different concentrations of yttria. Creep began as soon as the load was applied and continued at a constantly decreasing rate until the load was removed. Temperature and stabilization had a pronounced effect on creep rate. The creep rate for 20% Y2O3-80% ZrO2 was 1/3 to 1/2 that of 8% Y2O3-92% ZrO2. Both magnesia and calcia stabilized ZrO2 crept at a rate 5 to 10 times that of the 20% Y2O3 material. A near proportionality between creep rate and applied stress was observed. The rate controlling process appeared to be thermally activated, with an activation energy of approximately 100 cal/gm mole K. Creep deformation was due to cracking and particle sliding

Mapping and Characterizing Subtidal Oyster Reefs Using Acoustic Techniques, Underwater Videography and Quadrat Counts

Populations of the eastern oyster Crassostrea virginica have been in long-term decline in most areas. A major hindrance to effective oyster management has been lack of a methodology for accurately and economically obtaining data on their distribution and abundance patterns. Here, we describe early results from studies aimed at development of a mapping and monitoring protocol involving acoustic techniques, underwater videography, and destructive sampling (excavated quadrats). Two subtidal reefs in Great Bay, New Hampshire, were mapped with side-scan sonar and with videography by systematically imaging multiple sampling cells in a grid covering the same areas. A single deployment was made in each cell, and a 5-10-s recording was made of a 0.25-m2 area; the location of each image was determined using a differential global position system. A still image was produced for each of the cells and all (n = 40 or 44) were combined into a single photomontage overlaid onto a geo-referenced base map for each reef using Arc View geographic information system. Quadrat (0.25 m2 ) samples were excavated from 9 or 10 of the imaged areas on each reef, and all live oysters were counted and measured. Intercomparisons of the acoustic, video, and quadrat data suggest: (1) acoustic techniques and systematic videography can readily delimit the boundaries of oyster reefs; (2) systematic videography can yield quantitative data on shell densities and information on reef structure; and (3) some combination of acoustics, systematic videography, and destructive sampling can provide spatially detailed information on oyster reef characteristics

Simulator evaluation of separation of display parameters in path-following tasks

A five degree of freedom, fixed base simulation changing the location of the displays for bank angle, pitch angle, heading angle, and the vertical and lateral displacement from an instrument landing system path was studied. It is shown that the accuracy of the lateral path following and the pilot aircraft system dynamic characteristics deteriorate when bank angle is displayed separated from the other attitudes. It is found that best results are obtained when bank, heading, and pitch angles are displayed together and vertical and lateral displacements are displayed at another location in the display

Efficiency of cloud condensation nuclei formation from ultrafine particles

Atmospheric cloud condensation nuclei (CCN) concentrations are a key uncertainty in the assessment of the effect of anthropogenic aerosol on clouds and climate. The ability of new ultrafine particles to grow to become CCN varies throughout the atmosphere and must be understood in order to understand CCN formation. We have developed the Probability of Ultrafine particle Growth (PUG) model to answer questions regarding which growth and sink mechanisms control this growth, how the growth varies between different parts of the atmosphere and how uncertainties with respect to the magnitude and size distribution of ultrafine emissions translates into uncertainty in CCN generation. The inputs to the PUG model are the concentrations of condensable gases, the size distribution of ambient aerosol, particle deposition timescales and physical properties of the particles and condensable gases. It was found in most cases that condensation is the dominant growth mechanism and coagulation with larger particles is the dominant sink mechanism for ultrafine particles. In this work we found that the probability of a new ultrafine particle generating a CCN varies from <0.1% to ~90% in different parts of the atmosphere, though in the boundary layer a large fraction of ultrafine particles have a probability between 1% and 40%. Some regions, such as the tropical free troposphere, are areas with high probabilities; however, variability within regions makes it difficult to predict which regions of the atmosphere are most efficient for generating CCN from ultrafine particles. For a given mass of primary ultrafine aerosol, an uncertainty of a factor of two in the modal diameter can lead to an uncertainty in the number of CCN generated as high as a factor for eight. It was found that no single moment of the primary aerosol size distribution, such as total mass or number, is a robust predictor of the number of CCN ultimately generated. Therefore, a complete description of the emissions size distribution is generally required for global aerosol microphysics models

Twenty-One New Light Curves of OGLE-TR-56b: New System Parameters and Limits on Timing Variations

Although OGLE-TR-56b was the second transiting exoplanet discovered, only one light curve, observed in 2006, has been published besides the discovery data. We present twenty-one light curves of nineteen different transits observed between July 2003 and July 2009 with the Magellan Telescopes and Gemini South. The combined analysis of the new light curves confirms a slightly inflated planetary radius relative to model predictions, with R_p = 1.378 +/- 0.090 R_J. However, the values found for the transit duration, semimajor axis, and inclination values differ significantly from the previous result, likely due to systematic errors. The new semimajor axis and inclination, a = 0.01942 +/- 0.00015 AU and i = 73.72 +/- 0.18 degrees, are smaller than previously reported, while the total duration, T_14 = 7931 +/- 38 s, is 18 minutes longer. The transit midtimes have errors from 23 s to several minutes, and no evidence is seen for transit midtime or duration variations. Similarly, no change is seen in the orbital period, implying a nominal stellar tidal decay factor of Q_* = 10^7, with a three-sigma lower limit of 10^5.7.Comment: 14 pages, 5 figures, accepted to Ap