Comparison of Structural Concepts for Transport Aircraft with a Tail Cone Turbine

An evaluation of three structural concepts for an advanced aircraft design with a tail cone turbine is presented. Structural models were developed using an innovative rapid finite element modeling tool called Conceptual Design Shop (CDS). CDS is an attempt to fill a gap in current finite element modeling software to automatically connect wings and tails to the fuselage with sufficient support structure in airframe models. For comparison with actual aircraft structures, a model of a transport aircraft design developed using CDS is compared with published structural weight data for a Boeing 737-200. A method for computing aerodynamic stability parameters from an MSC/NASTRAN finite element analysis output deck is also discussed. Finally, the weight effects for using a tail cone turbine in an advanced transport aircraft design are evaluated by comparing three composite structural models, for which component thicknesses and cross-sections are sized by the Hypersizer software

Speckle interferometry at the Blanco and SOAR telescopes in 2008 and 2009

The results of speckle interferometric measurements of binary and multiple stars conducted in 2008 and 2009 at the Blanco and SOAR 4-m telescopes in Chile are presented. A total of 1898 measurements of 1189 resolved pairs or sub-systems and 394 observations of 285 un-resolved targets are listed. We resolved for the first time 48 new pairs, 21 of which are new sub-systems in close visual multiple stars. Typical internal measurement precision is 0.3 mas in both coordinates, typical companion detection capability is $\Delta m \sim 4.2$ at 0\farcs15 separation. These data were obtained with a new electron-multiplication CCD camera; data processing is described in detail, including estimation of magnitude difference, observational errors, detection limits, and analysis of artifacts. We comment on some newly discovered pairs and objects of special interest.Comment: Accepted for publication in Astronomical Journal. Tables 4,5,7 will be published electronically, they are available in full from the author

\u3ci\u3ePassage In The Night\u3c/i\u3e

The fire had gone out and I was unable to get it started again. I had been a Boy Scout and all that, but without dry kindling I could not get more than a few flickers of flame

Comparison of Abiotic and Biotic Factors Between Coves of Varying Connection to Harlan County Reservoir, Nebraska

Sediment berms of various heights have developed in the mouths of several coves within Harlan County Reservoir due to a combination of sediment deposition and lateral drift of eroded sediments. These berms can isolate coves from the main reservoir if the berm height is greater than the water elevation of the reservoir. Disconnection of coves may impact water quality, zooplankton, and fish within the isolated reservoir habitats. This study will examine differences in water quality parameters, zooplankton communities, and fish assemblages between disconnected coves, connected coves and the main reservoir. Water quality parameters related to water clarity and productivity differed between habitat types, with disconnected coves having higher turbidity and relative chlorophyll a readings, and lower secchi depths compared to the main reservoir. Connected coves had intermediate values between disconnected coves and the main reservoir. Disconnected coves also had increased densities of zooplankton. Zooplankton assemblages differed between habitats. Both cove types had increased abundance of rotifers within their assemblages, however this was more pronounced in disconnected coves. The main reservoir had increased Daphnia spp. compared to disconnected coves. Ordination of the zooplankton assemblages showed high community consistency within the main reservoir, compared to more variability within connected and disconnected coves. Connected coves had increased species richness and Shannon’s diversity compared to disconnected coves. Jaccard’s similarity index indicated that habitats were similar in species composition, however their assemblages had low similarity based on Renkonen Similarity Index. Ordination of the fish community showed connected coves had distinct fish assemblages compared to disconnected coves. Disconnected coves had large variability in fish assemblages. White Bass, Freshwater Drum, Channel Catfish, Gizzard Shad, River Carp Sucker, Walleye, Shortnose Gar, Northern Pike, Western Mosquitofish, Largemouth Bass, and Red Shiner were indicator species for connected coves. Disconnected coves had no species that were indicators