Investigation of methods for predicting the aerodynamic characteristics of two-lobed parawings

Accurate methods for predicting longitudinal aerodynamic characteristics of two-lobed conical parawings with leading edge boom

A new genus and species of stygobiontic dytiscid beetle, Comaldessus stygius (Coleoptera: Dytiscidae: Bidessini) from Comal Springs, Texas

A new genus and species of stygobiontic bidessine dytiscid beetle, Comaldessus stygius, from Comal Springs, Texas, is described and compared with the proposed sister epigean genus Uuarus and the only other known stygobiontic bidessine water beetles, Trogloguignotus concii Sanfilippo from Venezuela and Uvarus chappuisi (Peschet) from Africa. Distinctive characters of the adult are illustrated with pen and ink drawings and scanning electron micrographs. The new taxon is the second stygobiontic bidessine genus with rudimentary eyes known from the Western Hemisphere and the first known from North America

A new genus and species of stygobiontic dytiscid beetle, \u3ci\u3eComaldessus stygius \u3c/i\u3e (Coleoptera: Dytiscidae: Bidessini) from Comal Springs, Texas

A new genus and species of stygobiontic bidessine dytiscid beetle, Comaldessus stygius, from Comal Springs, Texas, is described and compared with the proposed sister epigean genus Uuarus and the only other known stygobiontic bidessine water beetles, Trogloguignotus concii Sanfilippo from Venezuela and Uvarus chappuisi (Peschet) from Africa. Distinctive characters of the adult are illustrated with pen and ink drawings and scanning electron micrographs. The new taxon is the second stygobiontic bidessine genus with rudimentary eyes known from the Western Hemisphere and the first known from North America

A new genus and species of stygobiontic dytiscid beetle, \u3ci\u3eComaldessus stygius \u3c/i\u3e (Coleoptera: Dytiscidae: Bidessini) from Comal Springs, Texas

A new genus and species of stygobiontic bidessine dytiscid beetle, Comaldessus stygius, from Comal Springs, Texas, is described and compared with the proposed sister epigean genus Uuarus and the only other known stygobiontic bidessine water beetles, Trogloguignotus concii Sanfilippo from Venezuela and Uvarus chappuisi (Peschet) from Africa. Distinctive characters of the adult are illustrated with pen and ink drawings and scanning electron micrographs. The new taxon is the second stygobiontic bidessine genus with rudimentary eyes known from the Western Hemisphere and the first known from North America

Calculation of the longitudinal aerodynamic characteristics of wing-flap configurations with externally blown flaps

A theoretical investigation was carried out to extend and improve an existing method for predicting the longitudinal characteristics of wing flap configurations with externally blown flaps (EBF). Two potential flow models were incorporated into the prediction method: a wing and flap lifting-surface model and a turbofan engine wake model. The wing-flap model uses a vortex-lattice approach to represent the wing and flaps. The jet wake model consists of a series of closely spaced vortex rings normal to a centerline which may have vertical and lateral curvature to conform to the local flow field beneath the wing and flaps. Comparisons of measured and predicted pressure distributions, span load distributions on each lifting surface, and total lift and pitching moment coefficients on swept and unswept EBF configurations are included. A wide range of thrust coefficients and flap deflection angles is considered at angles of attack up to the onset of stall. Results indicate that overall lift and pitching-moment coefficients are predicted reasonably well over the entire range. The predicted detailed load distributions are qualitatively correct and show the peaked loads at the jet impingement points, but the widths and heights of the load peaks are not consistently predicted

An exploratory aerodynamic and structural investigation of all-flexible parawings

Aerodynamic and structural aspects of all-flexible parawing

Computer Simulation of Cytoskeleton-Induced Blebbing in Lipid Membranes

Blebs are balloon-shaped membrane protrusions that form during many physiological processes. Using computer simulation of a particle-based model for self-assembled lipid bilayers coupled to an elastic meshwork, we investigated the phase behavior and kinetics of blebbing. We found that blebs form for large values of the ratio between the areas of the bilayer and the cytoskeleton. We also found that blebbing can be induced when the cytoskeleton is subject to a localized ablation or a uniform compression. The results obtained are qualitatively in agreement with the experimental evidence and the model opens up the possibility to study the kinetics of bleb formation in detail.Comment: To appear in Physical Review

Assessment of a wake vortex flight test program

A proposed flight test program to measure the characteristics of wake vortices behind a T-33 aircraft was investigated. A number of facets of the flight tests were examined to define the parameters to be measured, the anticipated vortex characteristics, the mutual interference between the probe aircraft and the wake, the response of certain instruments to be used in obtaining measurements, the effect of condensation on the wake vortices, and methods of data reduction. Recommendations made as a result of the investigation are presented

High intensity 5 eV O-atom exposure facility for material degradation studies

An atomic oxygen exposure facility was developed for studies of material degradation. The goal of these studies is to provide design criteria and information for the manufacture of long life (20 to 30 years) construction materials for use in low Earth orbit. The studies that are being undertaken will provide: (1) absolute reaction cross sections for the engineering design problems, (2) formulations of reaction mechanisms for use in the selection of suitable existing materials and the design of new more resistant ones, and (3) the calibration of flight hardware (mass spectrometers, etc.) in order to directly relate experiments performed in low Earth orbit to ground based investigations. The facility consists of a CW laser sustained discharge source of O-atoms, an atomic beam formation and diagnostics system, a spinning rotor viscometer, and provision for using the system for calibration of actual flight instruments

Mass spectrometers and atomic oxygen

The likely role of atmospheric atomic oxygen in the recession of spacecraft surfaces and in the shuttle glow has revived interest in the accurate measurement of atomic oxygen densities in the upper atmosphere. The Air Force Geophysics Laboratory is supplying a quadrupole mass spectrometer for a materials interactions flight experiment being planned by the Johnson Space Center. The mass spectrometer will measure the flux of oxygen on test materials and will also identify the products of surface reactions. The instrument will be calibrated at a new facility for producing high energy beams of atomic oxygen at the Los Alamos National Laboratory. The plans for these calibration experiments are summarized