An analysis of the gust-induced overspeed trends of helicopter rotors

Equations for analyzing the potential gust-induced overspeed tendency of helicopter rotors are presented. A parametric analysis was also carried out to illustrate the sensitivity of rotor angular acceleration to changes in rotor lift, propulsive force, tip speed, and forward velocity

A parametric study of blade-motion stability boundaries for an articulated rotor

Numerical solution of coupled, nonlinear, equation of motion for rigid blade to simulate response sensitivity and blade-motion stability of fully articulated roto

Blood transfusion in liver transplantation

Liver transplantation is a relatively new procedure in which unusually large quantities of blood are used. Blood use in 68 adult and 49 pediatric liver transplants was reviewed. The median (range) intraoperative red cell use for adults and children was 28.5 (3‐251) and 11 (2‐55), respectively. Blood use closely correlated with the patient's primary diagnosis. Adult patients with primary biliary cirrhosis and carcinoma used about one‐half as much blood as those with a diagnosis of sclerosing cholangitis, hepatitis, or cirrhosis. Patients in the former diagnostic groups also had better survival rates. Total red cell use for the patient's entire hospitalization was about twice that used during surgery. Fresh‐frozen plasma use paralleled red cell transfusions, but platelet use was modest. These data can serve as a baseline in helping other hospital transfusion services prepare for the advent of liver transplantation in their institutions. 1985 AAB

Secondary gamma-ray production in a coded aperture mask

The application of the coded aperture mask to high energy gamma-ray astronomy will provide the capability of locating a cosmic gamma-ray point source with a precision of a few arc-minutes above 20 MeV. Recent tests using a mask in conjunction with drift chamber detectors have shown that the expected point spread function is achieved over an acceptance cone of 25 deg. A telescope employing this technique differs from a conventional telescope only in that the presence of the mask modifies the radiation field in the vicinity of the detection plane. In addition to reducing the primary photon flux incident on the detector by absorption in the mask elements, the mask will also be a secondary radiator of gamma-rays. The various background components in a CAMTRAC (Coded Aperture Mask Track Chamber) telescope are considered. Monte-Carlo calculations are compared with recent measurements obtained using a prototype instrument in a tagged photon beam line

Operating characteristics of a prototype high energy gamma-ray telescope

The field of gamma-ray astronomy in the energy range from ten to several hundred MeV is severely limited by the angular resolution that can be achieved by present instruments. The identification of some of the point sources found by the COS-B mission and the resolution of detailed structure existing in those sources may depend on the development of a new class of instrument. The coded aperture mask telescope, used successfully at X-ray energies hold the promise of being such an instrument. A prototype coded aperture telescope was operated in a tagged photon beam ranging in energy from 23 to 123 MeV. The purpose of the experiment was to demonstrate the feasibility of operating a coded aperture mask telescope in this energy region. Some preliminary results and conclusions drawn from some of the data resulting from this experiment are presented

Delta isobar masses, large N_c relations, and the quark model

Motivated by recent remarks on the Delta+ mass and comparisons between the quark model and relations based on large-N_c with perturbative flavor breaking, two sets of Delta masses consistent with these constraints are constructed. These two sets, based either on an experimentally determined mass splitting or a quark model of isospin symmetry breaking, are shown to be inconsistent. The model dependence of this inconsistency is examined, and suggestions for improved experiments are made. An explicit quark model calculation and mass relations based on the large-N_c limit with perturbative flavor breaking are compared. The expected level of accuracy of such relations is realized in the quark model, except for mass relations spanning more than one SU(6) representation. It is shown that the Delta0 and Delta++ pole masses and Delta0 - Delta+ = (Delta- - Delta++)/3 about 1.5 MeV are more consistent with model expectations than the analogous Breit-Wigner masses and their splittings.Comment: 10 pages, including 1 eps figure, revte

Defining authorship in user-generated content : copyright struggles in The Game of Thrones

The notion of authorship is a core element in antipiracy campaigns accompanying an emerging copyright regime, worldwide. These campaigns are built on discourses that aim to ‘problematize’ the issues of ‘legality’ of content downloading practices, ‘protection’ for content creators and the alleged damage caused to creators’ livelihood by piracy. Under these tensions, fandom both subverts such discourses, through sharing and production practices, and legitimizes industry’s mythology of an ‘original’ author. However, how is the notion of authorship constructed in the cooperative spaces of fandom? The article explores the most popular fandom sites of A Song of Ice and Fire, the book series that inspires the TV-show Game of Thrones and argues that the notion of authorship is not one-dimensional, but rather consists of attributes that develop across three processes: community building, the creative and the industrial/production process. Here, fandom constructs a figure of the ‘author’ which, although more complex than the one presented by the industry in its copyright/anti-piracy campaigns, maintains the status quo of regulatory frameworks based on the idea of a ‘primary’ creator

Current collection to long conductors with wide geometries for bare electrodynamic tether applications - A laboratory update

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77101/1/AIAA-2002-1123-228.pd

Language and social/emotional problems identified at a universal developmental assessment at 30 months

Non peer reviewedPublisher PD

The Interstellar Environment of our Galaxy

We review the current knowledge and understanding of the interstellar medium of our galaxy. We first present each of the three basic constituents - ordinary matter, cosmic rays, and magnetic fields - of the interstellar medium, laying emphasis on their physical and chemical properties inferred from a broad range of observations. We then position the different interstellar constituents, both with respect to each other and with respect to stars, within the general galactic ecosystem.Comment: 39 pages, 12 figures (including 3 figures in 2 parts