Finite element analysis of helicopter structures

Application of the finite element analysis is now being expanded to three dimensional analysis of mechanical components. Examples are presented for airframe, mechanical components, and composite structure calculations. Data are detailed on the increase of model size, computer usage, and the effect on reducing stress analysis costs. Future applications for use of finite element analysis for helicopter structures are projected

A process yields large quantities of pure ribosome subunits

Development of process for in-vitro protein synthesis from living cells followed by dissociation of ribosomes into subunits is discussed. Process depends on dialysis or use of chelating agents. Operation of process and advantages over previous methods are outlined

K Giants in Baade's Window. II. The Abundance Distribution

This is the second in a series of papers in which we analyze spectra of over 400 K and M giants in Baade's Window, including most of the stars with proper motions measured by Spaenhauer et al. [AJ, 103, 297 (1992)]. In our first paper, we measured line--strength indices of Fe, Mg, CN and H$\beta$ and calibrated them on the system of Faber et al. [ApJS, 57, 711 (1985)]. Here, we use the $\langle{\rm Fe}\rangle$ index to derive an abundance distribution in [Fe/H] for 322 stars with effective temperatures between 3900 K and 5160 K. Our derived values of [Fe/H] agree well with those measured from high--resolution echelle spectra (e.g., McWilliam \& Rich [ApJS, 91, 749 (1994)]) for the small number of stars in common. We find a mean abundance $\langle{\rm [Fe/H]}\rangle = -0.11 \pm 0.04$ for our sample of Baade's Window K giants. More than half the sample lie in the range $-0.4 <$ \feh\ $<+0.3$. We estimate line--of--sight distances for individual stars in our sample and confirm that, in Baade's Window, most K giants with $V < 15.5$ are foreground disk stars, but the great majority (more than 80\%) with $V > 16$ belong to the bulge. We also compare the metallicities derived from the CN and Mg$_2$ indices to those from iron. Most of the metal--rich stars in our sample appear to be CN--weak, in contrast to the situation in metal--rich globular clusters and elliptical galaxies. The metal--poor half of our sample ([Fe/H] $< 0$) shows evidence for a mild Mg overenhancement ([Mg/Fe] $\sim +0.2$); but this is not seen in the more metal--rich stars ([Fe/H] $\geq$ 0). The K giants in Baade's Window therefore share some, but not all, of the characteristics of stars in elliptical galaxies as inferred from their integrated light.Comment: Accepted for publication in the Astronomical Journal, tentatively scheduled for July, 1996. LaTex source which generates 40 pages of text (no figures or tables). Complete (text + 15 figs + 5 tables) preprint in gzip/tar format is also available at ftp://bessel.mps.ohio-state.edu/pub/terndrup/kg2.tar.gz (227 kbyte

WFPC2 Observations of Star Clusters in the Magellanic Clouds: I. The LMC Globular Cluster Hodge 11

We present our analysis of Hubble Space Telescope Wide Field Planetary Camera 2 observations in F555W (broadband V) and F450W (broadband B) of the globular cluster Hodge 11 in the Large Magellanic Cloud galaxy. The resulting V vs. (B-V) color-magnitude diagram reaches 2.4 mag below the main-sequence turnoff (which is at V_TO = 22.65 +- 0.10 mag or M_V^TO = 4.00 +- 0.16 mag). Comparing the fiducial sequence of Hodge 11 with that of the Galactic globular cluster M92, we conclude that, within the accuracy of our photometry, the age of Hodge 11 is identical to that of M92 with a relative age-difference uncertainty ranging from 10% to 21%. Provided that Hodge 11 has always been a part of the Large Magellanic Cloud and was not stripped from the halo of the Milky Way or absorbed from a cannibalized dwarf spheroidal galaxy, then the oldest stars in the Large Magellanic Clouds and the Milky Way appear to have the same age.Comment: 14 pages (LaTeX+aaspp4.sty), 3 tables and 4 figures (Postscript, gzipped tar file). Postscript version of paper, tables, and full-resolution figures available at http://www.astro.columbia.edu/~mighell/hodge11.html To appear in the Astronomical Journa

Engineering Guidelines for Clean Assembly and Sterilization of Spaceflight Hardware

Engineering specifications for clean assembly and sterilization of space flight hardware to prevent contamination of planetary environment

Flight service evaluation of composite helicopter components

This first interim report presents the technical background for including environmental effects in the design of helicopter composite structures, and test results after approximately two year field exposure of components and panels. Composite structural components were removed from Sikorsky S-76 helicopters commercially operated in the Gulf Coast region of Louisiana. Fatigue tests were conducted for a graphite/epoxy tail rotor spar and static test for a graphite/epoxy and Kevlar/epoxy stabilizer. Graphite/epoxy and Kevlar/epoxy panels are being exposed to the outdoor environment in Stratford, Connecticut and West Palm Beach, Florida. For this reporting period the two year panels were returned, moisture measurements taken, and strength tests conducted. Results are compared with initial type certificate strengths for components and with initial laboratory coupon tests for the exposed panels. Comparisons are also presented with predicted and measured moisture contents

A SPATIAL MODEL OF ANIMAL DISEASE CONTROL IN LIVESTOCK: EMPIRICAL ANALYSIS OF FOOT AND MOUTH DISEASE IN THE SOUTHERN CONE

This paper presents a multi-market model of animal disease control that extends the current literature by accounting for spatial and inter-temporal relations in both epidemiological and economic variables. The model is applied to Foot and Mouth Disease control in Argentina, Uruguay and Paraguay, but it is broadly generalizable.Research Methods/ Statistical Methods,

Flight service evaluation of composite helicopter components

An assessment of composite helicopter structures, exposed to environmental effects, after four years of commercial service is presented. This assessment is supported by test results of helicopter components and test panels which have been exposed to environmental effects since late 1979. Full scale static and fatigue tests are being conducted on composite components obtained from S-76 helicopters in commercial operations in the Gulf Coast region of Louisiana. Small scale tests are being conducted on coupons obtained from panels being exposed to outdoor conditions in Stratford, Connecticut and West Palm Beach, Florida. The panel layups represent S-76 components. Moisture evaluations and strength tests are being conducted, on the S-76 components and panels, over a period of eight years. Results are discussed for components and panels with up to four years of exposure