595 research outputs found

    Preliminary Model Tests of a Wing-Duct Cooling System for Radial Engines, Special Report

    Get PDF
    Wind-tunnel tests were conducted on a model wing-nacelle combination to determine the practicability of cooling radial engines by forcing the cooling air into wing-duct entrances located in the propeller slipstream, passing the air through the engine baffles from rear to front, and ejecting the air through an annular slot near the front of the nacelle. The tests, which were of a preliminary nature, were made on a 5-foot-chord wing and a 20-inch-diameter nacelle. A 3-blade, 4-foot-diameter propeller was used. The tests indicated that this method of cooling and cowling radial engines is entirely practicable providing the wing of the prospective airplane is sufficiently thick to accommodate efficient entrance ducts , The drag of the cowlings tested was definitely less than for the conventional N.A.C.A. cowling, and the pressure available at low air speed corresponding to operation on the ground and at low flying speeds was apparently sufficient for cooling most present-day radial engines

    Preliminary Tests of Nose- and Side- Entrance Blower Cooling Systems for Radial Engines, Special Report

    Get PDF
    Two cowling systems intended to reduce the drag and improve the low-speed cooling characteristics of conventional radial engine cowlings were tested in model form to determine the practicability of the methods. One cowling included a blower mounted on the rear face of a large propeller spinner which drew cooling air in through side entrance ducts located behind the equivalent engine orifice plate. The air was passed through the equivalent engine orifice plate from rear to front and out through a slot between the spinner and the engine plate. The blower produced substantially all the power necessary to circulate the cooling air in some cases, so the quantity of air flowing was independent of the air speed, Two types of blowers were used, a centrifugal type and one using airfoil blades which forced the air outward from the center of rotation. The other cowling was similar to the conventional N.A.C.A. cowling except for the addition of a large propeller spinner nose. The spinner was provided with a hole in the nose to admit cooling air and blower blades to increase the pressure for cooling at low speeds. The tests show that with both cowling types the basic drag of the nacelle was reduced substantially below that for the N.A.C.A. cowling by virtue of the better nose shape made possible by the spinner . The drag due to the side-entrance ducts was nearly zero when the openings were closed or when the blower was drawing in a certain quantity of air in proportion to the air speed. The drag increased, however, when air mas allowed to spill from the openings. The nose-entrance blower showed considerable promise as a cooling means although the blower tested was relatively inefficient, owing to the fact that the blower compartments evidently were expanded too rapidly under the conditions imposed. by the design

    Preliminary Tests of Blowers of Three Designs Operating in Conjunction with a Wing-Duct Cooling System for Radial Engines, Special Report

    Get PDF
    This paper is one of several dealing with methods intended to reduce the drag of present-day radial engine installations and improve the cooling at zero and low air speeds, The present paper describes model wind-tunnel tests of blowers of three designs tested in conjunction with a wing-nacelle combination. The principle of operation involved consists of drawing cooling air into ducts located in the wing root at the point of maximum slipstream velocity, passing the air through the engine baffles from rear to front, and exhausting the air through an annular slot located between the propeller and the engine with the aid of a blower mounted on the spinner. The test apparatus consisted essentially of a stub wing having a 5-foot chord and a 15-foot span, an engine nacelle of 20 inches diameter enclosing a 25-horsepower electric motor, and three blowers mounted on propeller spinners. Two of the blowers utilize centrifugal force while the other uses the lift from airfoils to force the air out radially through the exit slot. Maximum efficiencies of over 70 percent were obtained for the system as a whole. Pressures were measured over the entire flight range which were in excess of those necessary to cool present-day engines, The results indicated that blowers mounted on propeller spinners could be built sufficiently powerful and efficient to warrant their use as the only, or chief, means of forcing air through the cooling system, so that cooling would be independent of the speed of the airplane

    Privatizing Functions of State Government

    Get PDF
    Privatization of traditional governmental functions has been extensively discussed in the United States for more than two decades, and states have chosen a wide range of programs for privatization and selected a variety of implementation and oversight strategies. In this report we examine the potential for privatization, privatization pitfalls, and ways to optimize the success of privatization effects. Privatization can be attractive for one of two different reasons. It may provide a revenue benefit when the contracting entity can provide the service at a lower cost than that experienced by the governing entity. Typically, lower costs arise from lower personnel costs or through the use of less expensive methods and technologies, including IT solutions. It may also be attractive because privatization may allow government to perform specific services more effectively or more efficiently than it could with its own employees. Typically, these situations occur when a private entity can be more flexible in the deployment of personnel and resources andwhen dealing with new technologies or processes.Includes bibliographical reference

    Institutional Effects of Term Limits In Missouri1

    Get PDF
    Missouri adopted term limits in 1992 but the limits did not take full effect until 2003 in the House and will take full effect in the Senate in 2005. Missouri's limit is a lifetime limit of eight years in each chamber, for a total of sixteen years. Initially the limit applied to partial terms for those elected in a special election but the amendment was revised in 2002 to exclude from the circulation service of less then one-half a term (i.e. one year in the House or two years in the Senate). The amendment can be found in article III, section 8 of the Missouri Constitution. In January 2003, no member of the House had served more than six consecutive years and in January 2005, no member of the Senate will have served more than six consecutive years. Those who have written about term limits do not agree about the probable effects and researchers have found that the effects of term limits vary significantly from state to state (see attached bibliography). This report draws on legislative data compiled by the Missouri Secretary of State, a legislative survey, and interviews to examine the impact of term limits on legislative leaders, new member learning and specialization, the role of legislative staff, and evolving lobbyingstrategies.Includes bibliographical reference

    Economic Impact of Gulf of Mexico Ecosystem Goods and Services and Integration Into Restoration Decision-Making

    Get PDF
    Sustainability of natural resources requires balancing exploitation and conservation, enabled by management based on the best available scientific and economic information. Valuation of ecosystem goods and services is an important tool for prioritizing restoration efforts, recognizing the economic importance of conserving natural capital, and raising public awareness about the contribution of healthy ecosystems to social welfare, now and for future generations. The Deepwater Horizon oil spill (DHOS) in 2010 was a Gulf of Mexico ecological and economic disaster adding to decades-long degradation of the region’s coastal and marine environment. In 2010, revenues from provisioning ecosystem goods and services generated by the five U.S. states bordering the Gulf of Mexico contributed over 2trillionperyeartothenation’sgrossdomesticproduct,including2 trillion per year to the nation’s gross domestic product, including 660 billion from the coastal county revenues and 110billionfromoceanrevenues.MexicoandCubacontributeatleastanother110 billion from ocean revenues. Mexico and Cuba contribute at least another 40 billion per year from their Gulf coastal and ocean economies. Total economic value of Gulf ecosystem goods and services also requires valuation of nonmarket regulating, cultural, and supporting services, which are far more difficult to assess, but add billions more dollars per year. In light of this total economic value and trends in ecosystem stressors, new investment is necessary to ensure completeness, accuracy, and availability of Gulf economic impact data. Civil and criminal settlements related to the DHOS provide unprecedented opportunities for improving integration of ecosystem goods and services into decisions that affect Gulf restoration and sustainability. This paper highlights the economic contributions of Gulf ecosystem goods and services to the nation’s welfare, and recommends actions and investments required to ensure that they are valued, and integrated into decision-making

    Mapping the Human Plasma Proteome by SCX-LC-IMS-MS

    Get PDF
    The advent of on-line multidimensional liquid chromatography-mass spectrometry has significantly impacted proteomic analyses of complex biological fluids such as plasma. However, there is general agreement that additional advances to enhance the peak capacity of such platforms are required to enhance the accuracy and coverage of proteome maps of such fluids. Here, we describe the combination of strong-cation-exchange and reversed-phase liquid chromatographies with ion mobility and mass spectrometry as a means of characterizing the complex mixture of proteins associated with the human plasma proteome. The increase in separation capacity associated with inclusion of the ion mobility separation leads to generation of one of the most extensive proteome maps to date. The map is generated by analyzing plasma samples of five healthy humans; we report a preliminary identification of 9087 proteins from 37,842 unique peptide assignments. An analysis of expected false-positive rates leads to a high-confidence identification of 2928 proteins. The results are catalogued in a fashion that includes positions and intensities of assigned features observed in the datasets as well as pertinent identification information such as protein accession number, mass, and homology score/confidence indicators. Comparisons of the assigned features reported here with other datasets shows substantial agreement with respect to the first several hundred entries; there is far less agreement associated with detection of lower abundance components

    A Database of Alkaline-Earth-Coordinated Peptide Cross Sections: Insight into General Aspects of Structure

    Get PDF
    Abstract. A database of 1470 collision cross sections (666 doubly-and 804 triplycharged) of alkaline-earth-coordinated tryptic peptide ions [where the cation (M 2+ ) correspond to Mg 2+ , Ca 2+ , or Ba 2+ ] is presented. The utility of such an extensive set of measurements is illustrated by extraction of general properties of M 2+ -coordinated peptide structures. Specifically, we derive sets of intrinsic size parameters (ISPs) for individual amino acid residues for M 2+ -coordinated peptides. Comparison of these parameters with existing ISPs for protonated peptides suggests that M 2+ binding occurs primarily through interactions with specific polar aliphatic residues (Asp, Ser, and Thr) and the peptide backbone. A comparison of binding interactions for these alkaline-earth metals with interactions reported previously for alkali metals is provided. Finally, we describe a new analysis in which ISPs are used as probes for assessing peptide structure based on amino acid composition

    Better Pumps: Reliable Handpump Infrastructure

    Get PDF
    Approximately 90 million people in Africa lack access to safe drinking water, despite having water infrastructure installed in their community. The India Mark II and the Afridev handpumps are among the most widely used handpumps in the world. Sadly, studies show that approximately 30% of these handpumps are non-operational due to failures of the bearings, seals, head flange, and other common components. The Better Pumps team of the Collaboratory provides engineering support for partners who are working to improve handpump sustainability. We partnered with Tony Beers and AlignedWorks to validate a bearing test methodology for the India Mark II handpump. By modifying the loading conditions in our handpump test machine, we were able to replicate failures observed by AlignedWorks in a field trial of their bearing design. We partnered with Matt Schwiebert and Living Water International to test new seal designs for the India Mark II and Afridev handpumps and to measure head flange deflections in the India Mark II handpump. Seal performance data collected by the team was used to validate a new design in advance of field trials by Living Water International. Head flange deflection data was collected for partner benchmarking of their computational analysis. Test methodologies and results are reported.https://mosaic.messiah.edu/engr2021/1000/thumbnail.jp
    • …
    corecore