3,102 research outputs found
Problems in determining sea surface topography
Anticipated problems for determining ocean dynamics signals from sea surface topography are discussed. The needs for repeated tracks are listed if oceanic tides or ocean turbulence are to be determined
Preliminary analysis of the span-distributed-load concept for cargo aircraft design
A simplified computer analysis of the span-distributed-load airplane (in which payload is placed within the wing structure) has shown that the span-distributed-load concept has high potential for application to future air cargo transport design. Significant increases in payload fraction over current wide-bodied freighters are shown for gross weights in excess of 0.5 Gg (1,000,000 lb). A cruise-matching calculation shows that the trend toward higher aspect ratio improves overall efficiency; that is, less thrust and fuel are required. The optimal aspect ratio probably is not determined by structural limitations. Terminal-area constraints and increasing design-payload density, however, tend to limit aspect ratio
Technical and Economic Evaluation of Advanced Air Cargo Systems
The current air cargo environment and the relevance of advanced technology aircraft in enhancing the efficiency of the 1990 air cargo system are discussed. NASA preliminary design studies are shown to indicate significant potential gains in aircraft efficiency and operational economics for future freighter concepts. Required research and technology elements are outlined to develop a better base for evaluating advanced design concepts. Current studies of the market operation are reviewed which will develop design criteria for a future dedicated cargo transport. Design features desirable in an all-freighter design are reviewed. NASA-sponsored studies of large, distributed-load freighters are reviewed and these designs are compared to current wide-body aircraft. These concepts vary in gross takeoff weight from 0.5 Gg (one million lbs.) to 1.5 Gg (three million lbs.) and are found to exhibit economic advantages over conventional design concepts
The promise of air cargo: System aspects and vehicle design
The current operation of the air cargo system is reviewed. An assessment of the future of air cargo is provided by: (1) analyzing statistics and trends, (2) by noting system problems and inefficiencies, (3) by analyzing characteristics of 'air eligible' commodities, and (4) by showing the promise of new technology for future cargo aircraft with significant improvements in costs and efficiency. The following topics are discussed: (1) air cargo demand forecasts; (2) economics of air cargo transport; (3) the integrated air cargo system; (4) evolution of airfreighter design; and (5) the span distributed load concept
Preliminary analysis of hub and spoke air freight distribution system
A brief analysis is made of the hub and spoke air freight distribution system which would employ less than 15 hub centers world wide with very large advanced distributed-load freighters providing the line-haul delivery between hubs. This system is compared to a more conventional network using conventionally-designed long-haul freighters which travel between numerous major airports. The analysis calculates all of the transportation costs, including handling charges and pickup and delivery costs. The results show that the economics of the hub/spoke system are severely compromised by the extensive use of feeder aircraft to deliver cargo into and from the large freighter terminals. Not only are the higher costs for the smaller feeder airplanes disadvantageous, but their use implies an additional exchange of cargo between modes compared to truck delivery. The conventional system uses far fewer feeder airplanes, and in many cases, none at all. When feeder aircraft are eliminated from the hub/spoke system, however, that system is universally more economical than any conventional system employing smaller line-haul aircraft
Characteristics of future air cargo demand and impact on aircraft development: A report on the Cargo/Logistic Airlift Systems Study (CLASS) project
Current domestic and international air cargo operations are studied and the characteristics of 1990 air cargo demand are postulated from surveys conducted at airports and with shippers, consignees, and freight forwarders as well as air, land, and ocean carriers. Simulation and route optimization programs are exercised to evaluate advanced aircraft concepts. The results show that proposed changes in the infrastructure and improved cargo loading efficiencies are as important enhancing the prospects of air cargo growth as is the advent of advanced freighter aircraft. Potential reductions in aircraft direct operating costs are estimated and related to future total revenue. Service and cost elasticities are established and utilized to estimate future potential tariff reductions that may be realized through direct and indirect operating cost reductions and economies of scale
Aeronautical fuel conservation possibilities for advanced subsonic transports
The anticipated growth of air transportation is in danger of being constrained by increased prices and insecure sources of petroleum-based fuel. Fuel-conservation possibilities attainable through the application of advances in aeronautical technology to aircraft design are identified with the intent of stimulating NASA R and T and systems-study activities in the various disciplinary areas. The material includes drag reduction; weight reduction; increased efficiency of main and auxiliary power systems; unconventional air transport of cargo; and operational changes
Demand for large freighter aircraft as projected by the NASA cargo/logistics airlift system studies
The market conditions are examined up through the year 2008 to provide a preliminary assessment of the potential for and the characteristics of an advanced, all-cargo transport aircraft. Any new freighter must compete with current wide-body aircraft and their derivatives. Aircraft larger than the wide-bodies may incur economic penalties and operational problems. A lower direct operating cost is not a sufficient criterion to base a decision for the initiation of a new aircraft development or to select aircraft characteristics. Other factors of equal importance that are reviewed in this paper include considerations of the system infrastructure, the economics of the airlines, and the aircraft manufacturer return on investment. The results of the market forecast and a computer simulation show that an advanced long range aircraft with a payload between 68 to 181 tonnes (75 to 200 tons) could generate a solid foothold beginning around 1994
An outlook for cargo aircraft of the future
An assessment is provided of the future of air cargo by analyzing air cargo statistics and trends, by noting air cargo system problems and inefficiencies, by analyzing characteristics of air-eligible commodities, and by showing the promise of new technology for future cargo aircraft with significant improvements in costs and efficiency. NASA's proposed program is reviewed which would sponsor the research needed to provide for development of advanced designs by 1985
Biopower: bodies, minds and biographical subjection in Victorian Lives of the Poets
This article discusses the diagnostic and exhibitionary character of nineteenth-century biographical discourse, with particular attention to Percy Bysshe Shelley. The article proposes that suggestive parallels between the life of the individual body and the textual materials of the written Life were often made in the nineteenth century. These parallels can be related to Foucauldian arguments about pastoral power and the individual subject, medicine and the case history, irrationality and juvenescence. The article argues that poetic subjects discussed as eccentric or pathological ‘genius’ were the ideal subjects and exemplify the proliferation and operation of forms of ‘biopower’. With these arguments in mind, the article analyses biographical writing about Shelley up to 1860. Specifically, the article discusses how Shelley’s biography moved from the somatic diagnosis of the poet’s ‘constitution consumptive’ in sketches by William Hazlitt and Leigh Hunt, to taking his thoughts, behaviour and writing as symptomatic of psychosomatic pathology. Looking in particular at the biographical productions of Thomas Jefferson Hogg and Thomas Medwin, the article suggests how ‘biopower’ compensated for the absence of the diagnosable body by concentrating on and disciplining the embodied mind, in line with nineteenth-century 'moral management', 'domestic psychiatry', and the construction of 'the mind of the child'. Finally, the article considers Victorian biography’s rhetoric of rational disenchantment and disillusionment, and suggests that it was conversely highly significant in establishing a version of beautifully and ineffectually irrational Romantic poetry. Looking forward to later periods, the article also proposes a pre-history of psychoanalytic or psycho-biographical criticism, and its ‘hermeneutics of suspicion’, in nineteenth- century biography
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