3,056 research outputs found
Landing impact studies of a 0.3-scale model air cushion landing system for a Navy fighter airplane
An experimental study was conducted in order to determine the landing-impact behavior of a 0.3-scale, dynamically (but not physically) similar model of a high-density Navy fighter equipped with an air cushion landing system. The model was tested over a range of landing contact attitudes at high forward speeds and sink rates on a specialized test fixture at the Langley aircraft landing loads and traction facility. The investigation indicated that vertical acceleration at landing impact was highly dependent on the pitch angle at ground contact, the higher acceleration of approximately 5g occurring near zero body-pitch attitude. A limited number of low-speed taxi tests were made in order to determine model stability characteristics. The model was found to have good pitch-damping characteristics but stability in roll was marginal
Small-scale Minimal-maintenance Anaerobic Digestion of Food Waste for Solids Reduction and Methane Production: Feasibility Study
Six gallons of food waste was anaerobically digested for 76 days in two small-scale digesters sitting by a lab window. The main difference, besides waste sources, of these digesters was substrate processing: chopping versus blending. An effort was made to minimize the maintenance of the digesters, however, after 45 days of overly acidic (p
Review of \u3ci\u3e Ice Age Peoples of North America: Environments, Origins, and Adaptations of the First Americans\u3c/i\u3e Edited by Robson Bonnichsen and Karen L. Turnmire
This collection of nineteen articles presents up-to-date regional or topical syntheses of the best data relating to the last Ice Age inhabitants in Northeast Asia, Beringia, and North America. Many of the papers were given in 1989 at the First World Summit, sponsored by the Center for the Study of the First Americans at the University of Maine. Authors were given the opportunity to update their syntheses to include new finds in their regions during the decade between the Summit and the book\u27s publication, though some contributors waived the opportunity
A comparison of six farrowing house slat materials
There were 410 crossbred Duroc, Hampshire, Landrace and Yorkshire sows and their litters used in this study to compare the self-cleaning properties of six different slat types and to relate slat cleanliness to pig performance. Each litter was raised to weaning (about 5 weeks of age) in a 24-crate environment controlled confinement farrowing house. Each partially slatted farrowing crate utilized one of six different slat types in the rear 30 inches of the crate. The slat materials, #9 expanded metal, Behlen stainless steel, round rods, flat steel, plastic and aluminum, were evaluated for cleanliness by objective numeric scoring of the slatted area at weekly intervals. Slat cleanliness was primarily related to percent void (slot) space in the slat section. Expanded metal, Behlen stainless steel and round rod slats had a greater percent void space and scored significantly cleaner than flat steel, aluminum and plastic slats. The slats constructed of materials more readily available for on-farm construction such as expanded metal, round rods and flat steel self-cleaned more effectively than the specialty slat materials such as stainless steel, plastic and aluminum. The age and number of pigs in the litter had little influence on slat cleanliness. Year and season of year differences affected the cleanliness of all slat types but did not affect the differences among slat types. Slat cleanliness had little influence on the percentage of pigs weaned of those born alive; however, the slat material itself significantly affected the percentage weaned. Expanded metal, round rods, Behlen stainless steel and flat steel slat materials were those associated with the lower weaning percentages of 74.3 and 69.5, respectively. There were no significant differences in adjusted 35-day pig weaning weight
Review of \u3ci\u3e Ice Age Peoples of North America: Environments, Origins, and Adaptations of the First Americans\u3c/i\u3e Edited by Robson Bonnichsen and Karen L. Turnmire
This collection of nineteen articles presents up-to-date regional or topical syntheses of the best data relating to the last Ice Age inhabitants in Northeast Asia, Beringia, and North America. Many of the papers were given in 1989 at the First World Summit, sponsored by the Center for the Study of the First Americans at the University of Maine. Authors were given the opportunity to update their syntheses to include new finds in their regions during the decade between the Summit and the book\u27s publication, though some contributors waived the opportunity
Calopogon pulchellus R. Br.
https://thekeep.eiu.edu/herbarium_specimens_byname/21301/thumbnail.jp
Calopogon pulchellus R. Br.
https://thekeep.eiu.edu/herbarium_specimens_byname/21301/thumbnail.jp
A Fight \u27Till the Death: Congress\u27s Usurpation of State Court Power in End-of-Life Matters
In the spring of 2005, the United States Congress passed An Act for the Relief for the Parents of Theresa Marie Schiavo ( the Act ) in response to numerous requests by Michael Schiavo, Theresa\u27s husband, to have Theresa\u27s feeding tube removed. Michael Schiavo argued that, prior to her accident, Theresa ( Terri ) made oral statements expressing her wish not to be kept alive in a persistent vegetative state. The Act provided a mechanism for the parents of Terri Schiavo to institute legal proceedings to prevent the removal of Terri\u27s feeding tube
Estimating firm technical efficiency using alternative frontier function approaches: an application to farrow to finish hog production units
The purpose of this study was to estimate the relative technical efficiency of individual farrow-to-finish swine production units and to analyze the relationship between firm technical efficiency and selected swine production practices. Study areas included 11 states in the North Central region and seven states in the Southeast region of the U.S. hog enterprise production data were obtained from a cross-sectional cost of production study conducted by the Economic Research Service, U.S.D.A. in 1981. Information available for 216 farrow-to-finish swine units in the North Central region and 339 farrow-to-finish swine units in the Southeast region was used to derive the empirical data on annual output and resource use of each swine unit. Technical efficiency was estimated for each firm using alternative frontier production function approaches. The frontier function approaches used were (1) the Farrell linear programming approach to estimating multifactor productivity measures of technical, scale, and input congestion efficiency, and (2) a statistical composed error frontier approach to measuring technical efficiency relative to a random stochastic frontier. The resulting estimates of technical efficiency were used as dependent variables in explanatory regression models which related technical efficiency among firms to specified production characteristics. Production characteristics specified as independent variables were sow herd production intensity, level of confinement, type of management,type of farm business organization, type of manure handling practices, and type of feed and feed processing practices. Linear programming measures of technical efficiency permitted the derivation of estimates of scale efficiency and congestion efficiency for each hog unit. Mean technical efficiency for hog units in each sample was higher as the frontier function was altered to allow variable returns to scale and weak input disposability in the frontier relation-ship. Results showed scale and congestion inefficiency to be minor compared to technical inefficiency among swine units in each regional sample. The statistical, stochastic frontier approach gave results showing that technical efficiency was higher for larger size hog units and the estimates of the parameters of the frontier indicated the elasticity of production was less than one for each factor and for all factors collectively. Results derived from regression models using the deterministic measure of technical efficiency showed very little explanatory power and in many instances the signs, magnitude of the coefficients obtained for explanatory variables were contrary to expectations. Estimates from the regression models using the stochastic frontier indicated a moderate degree of explanation for the variation in technical among firms and estimated coefficients were more plausible. The existence of technical inefficiency in the hog production process seems quite well documented, but the determinants of hog farm technical efficiency are still unclear based on the results of this study
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