16,046 research outputs found
A new concept for airship mooring and ground handling
Calculations were made to determine the feasibility of applying the negative air cushion (NAC) principle to the mooring of airships. Pressures required for the inflation of the flexible trunks are not excessive and the maintenance of sufficient hold down force is possible in winds up to 50 knots. Fabric strength requirements for a typical NAC sized for a 10-million cubic foot airship were found to be approximately 200 lbs./in. Corresponding power requirements range between 66-HP and 5600-HP. No consideration was given to the internal airship loads caused by the use of a NAC and further analysis in much greater detail is required before this method could be applied to an actual design, however, the basic concept appears to be sound and no problem areas of a fundamental nature are apparent
An Educational Pathway for Geriatric Home Caregivers
The establishment of a multi-tiered educational pathway for geriatric home caregivers would support efforts to meet the needs of an increasing number of community dwelling older adults who require assistance with activities of daily living, while generating a cadre of qualified employees for an expanding non-medical private home care market. An educational pathway for geriatric home caregivers would also standardize the training of home care assistants while providing these individuals access to routine, high quality continuing education opportunities and the potential for career advancement. This issue brief provides two model educational pathways toward becoming a Geriatric Home Caregiver
A softer look at MCG--6-30-15 with XMM-Newton
We present analysis and results from the Reflection Grating Spectrometer
during the 320 ks XMM observation of the Seyfert 1 galaxy MCG-6-30-15. The
spectrum is marked by a sharp drop in flux at 0.7 keV which has been
interpreted by Branduardi-Raymont et al. as the blue wing of a relativistic
OVIII emission line and by Lee at al. as a dusty warm absorber. We find that
the drop is well explained by the FeI L2,3 absorption edges and obtain
reasonable fits over the 0.32-1.7 keV band using a multizone, dusty warm
absorber model. Some residuals remain which could be due to emission from a
relativistic disc, but at a much weaker level than from any model relying on
relativistic emission lines alone. A model based on such emission lines can be
made to fit if sufficient (warm) absorption is added, although the line
strengths exceed those expected. The EPIC pn difference spectrum between the
highest and lowest flux states of the source indicates that this is a power-law
in the 3-10 keV band which, if extrapolated to lower energies, reveals the
absorption function acting on the intrinsic spectrum, provided that any
emission lines do not scale exactly with the continuum. We find that this
function matches our dusty warm absorber model well. The soft X-ray spectrum is
therefore dominated by absorption structures, with the equivalent width of any
individual emission lines in the residuals being below about 30 eV. (abridged)Comment: 8 pages, 10 figures, submitted to MNRA
Multirole cargo aircraft options and configurations
A future requirements and advanced market evaluation study indicates derivatives of current wide-body aircraft, using 1980 advanced technology, would be economically attractive through 2008, but new dedicated airfreighters incorporating 1990 technology, would offer little or no economic incentive. They would be economically attractive for all payload sizes, however, if RD and T costs could be shared in a joint civil/military arrangement. For the 1994-2008 cargo market, option studies indicate Mach 0.7 propfans would be economically attractive in trip cost, aircraft price and airline ROI. Spanloaders would have an even lower price and higher ROI but would have a relatively high trip cost because of aerodynamic inefficiencies. Dedicated airfreighters using propfans at Mach 0.8 cruise, laminar flow control, or cryofuels, would not provide any great economic benefits. Air cushion landing gear configurations are identified as an option for avoiding runway constraints on airport requirements and/or operational constraints are noted
Technology requirements and readiness for very large aircraft
Common concerns of very large aircraft in the areas of economics, transportation system interfaces and operational problems were reviewed regarding their influence on vehicle configurations and technology. Fifty-four technology requirements were identified which are judged to be unigue, or particularly critical, to very large aircraft. The requirements were about equally divided among the four general areas of aerodynamics, propulsion and acoustics, structures, and vehicle systems and operations. The state of technology readiness was judged to be poor to fair for slightly more than one-half of the requirements. In the classic disciplinary areas, the state of technology readiness appears to be more advanced than for vehicle systems and operations
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