Energy Efficient Engine Program Advanced Turbofan Nacelle Definition Study

Advanced, low drag, nacelle configurations were defined for some of the more promising propulsion systems identified in the earlier Benefit/Cost Study, to assess the benefits associated with these advanced technology nacelles and formulate programs for developing these nacelles and low volume thrust reversers/spoilers to a state of technology readiness in the early 1990's. The study results established the design feasibility of advanced technology, slim line nacelles applicable to advanced technology, high bypass ratio turbofan engines. Design feasibility was also established for two low volume thrust reverse/spoiler concepts that meet or exceed the required effectiveness for these engines. These nacelle and thrust reverse/spoiler designs were shown to be applicable in engines with takeoff thrust sizes ranging from 24,000 to 60,000 pounds. The reduced weight, drag, and cost of the advanced technology nacelle installations relative to current technology nacelles offer a mission fuel burn savings ranging from 3.0 to 4.5 percent and direct operating cost plus interest improvements from 1.6 to 2.2 percent

Energy Efficient Engine: Control system preliminary definition report

The object of the Control Preliminary Definition Program was to define a preliminary control system concept as a part of the Energy Efficient Engine program. The program was limited to a conceptual definition of a full authority digital electronic control system. System requirements were determined and a control system was conceptually defined to these requirements. Areas requiring technological development were identified and a plan was established for implementing the identified technological features, including a control technology demonstration. A significant element of this program was a study of the potential benefits of closed-loop active clearance control, along with laboratory tests of candidate clearance sensor elements for a closed loop system

Energy Efficient Engine: High-pressure compressor test hardware detailed design report

The objective of the NASA Energy Efficient Engine program is to identify and verify the technology required to achieve significant reductions in fuel consumption and operating cost for future commercial gas turbine engines. The design and analysis is documented of the high pressure compressor which was tested as part of the Pratt and Whitney effort under the Energy Efficient Engine program. This compressor was designed to produce a 14:1 pressure ratio in ten stages with an adiabatic efficiency of 88.2 percent in the flight propulsion system. The corresponding expected efficiency for the compressor component test rig is 86.5 percent. Other performance goals are a surge margin of 20 percent, a corrected flow rate of 35.2 kg/sec (77.5 lb/sec), and a life of 20,000 missions and 30,000 hours. Low loss, highly loaded airfoils are used to increase efficiency while reducing the parts count. Active clearance control and case trenches in abradable strips over the blade tips are included in the compressor component design to further increase the efficiency potential. The test rig incorporates variable geometry stator vanes in all stages to permit maximum flexibility in developing stage-to-stage matching. This provision precluded active clearance control on the rear case of the test rig. Both the component and rig designs meet or exceed design requirements with the exception of life goals, which will be achievable with planned advances in materials technology

Media Coverage and Perceived Policy Influence of Environmental Actors: Good Strategy or Pyrrhic Victory?

In this article we analyze how media coverage for environmental actors (individual environmental activists and environmental movement organizations) is associated with their perceived policy influence in Canadian climate change policy networks. We conceptualize media coverage as the total number of media mentions an actor received in Canada’s two main national newspapers—the Globe and Mail and National Post. We conceptualize perceived policy influence as the total number of times an actor was nominated by other actors in a policy network as being perceived to be influential in domestic climate change policy making in Canada. Literature from the field of social movements, agenda setting, and policy networks suggests that environmental actors who garner more media coverage should be perceived as more influential in policy networks than actors who garner less coverage. We assess support for this main hypothesis in two ways. First, we analyze how actor attributes (such as the type of actor) are associated with the amount of media coverage an actor receives. Second, we evaluate whether being an environmental actor shapes the association between media coverage and perceived policy influence. We find a negative association between media coverage and perceived policy influence for individual activists, but not for environmental movement organizations. This case raises fundamental theoretical questions about the nature of relations between media and policy spheres, and the efficacy of media for signaling and mobilizing policy influence

Electron Correlations in the Low Carrier Density LaFeAsO0.89F0.11 Superconductor (Tc = 28 K)

The crystal structure and numerous normal and superconducting state properties of layered tetragonal (P4/nmm) LaFeAsO, with F-doping of 11 %, are reported. Resistivity measurements give an onset transition temperature Tc = 28.2 K, and low field magnetic susceptibility data indicate bulk superconductivity. In applied magnetic field, analysis of the resistive transition results in a critical field Hc2 = 30 T and a coherence length 35 A. An upper limit for the electron carrier concentration of 1 x 10^21 cm-3 is inferred from Hall data just above Tc. Strong electron-electron correlations are suggested from temperature-dependent resistivity, Seebeck coefficient, and thermal conductivity data. Anomalies near Tc are observed in both Seebeck coefficient and thermal conductivity data.Comment: 13 pages, 8 figure

Dynamics of the DBI Spike Soliton

We compare oscillations of a fundamental string ending on a D3-brane in two different settings: (1) a test-string radially threading the horizon of an extremal black D3-brane and (2) the spike soliton of the DBI effective action for a D3-brane. Previous work has shown that overall transverse modes of the test-string appear as l=0 modes of the transverse scalar fields of the DBI system. We identify DBI world-volume degrees of freedom that have dynamics matching those of the test-string relative transverse modes. We show that there is a map, resembling T-duality, between relative and overall transverse modes for the test-string that interchanges Neumann and Dirichlet boundary conditions and implies equality of the absorption coefficients for both modes. We give general solutions to the overall and relative transverse parts of the DBI coupled gauge and scalar system and calculate absorption coefficients for the higher angular momentum modes in the low frequency limit. We find that there is a nonzero amplitude for l>0 modes to travel out to infinity along the spike, demonstrating that the spike remains effectively 3+1-dimensional.Comment: 15 pages, 1 figur

Book Reviews

Reviews of the following books: The Lobster Coast: Rebels, Rusticators, and the Struggle for Forgotten Frontier by Colin Woodard; Writing on Stone: Scenes from a Maine Island Life by Christina Marsden Gillis; photographs by Peter Ralston and Forward by Philip Conkling; Owascoag, Black Poynt, Mayne: History of Black Point (Scarborough) Maine, ca. 1600-1800: A Narrative by Patricia Bowden Corey; Continental Liar from the State of Maine: James G. Blaine by Neil Rolde; No Flies on Bill : The Story of an Uncontrollable Old Woman, My Grandmother, Ethel Billie Gammon by Darcy Wakefield; An Upriver Passamaquoddy by Allan J. Sockabasin; Rug Hooking in Maine, 1838 - 1940 by Mildred Cole Peladea

Book Reviews

Reviews of the following books: Mount Hope Cemetery of Bangor, Maine: The Complete History by Trudy Irene Scee; The Reverend Jacob Bailey, Maine Loyalist: For God, King, Country and for Self by James S. Leamon; The Barns of Maine: Our History, Our Stories by Don Perkins; Gateway to Vacationland: The Making of Portland, Maine by John F. Bauman; Maine: The Wilder Half of New England by William David Berry; The Cross of War: Christian Nationalism and U.S. Expansion in the Spanish-American War by Matthew McCullough; Omaha Beach: The Life and Military Service of a Penobscot Indian Elder by Charles Norman Shay

Exploring stakeholder perceptions of conservation outcomes from alternative income generating activities in Tanzanian villages adjacent to Eastern Arc Mountain forests

AbstractCritical evaluation of the impact of conservation actions is essential to meet the challenges posed by the biodiversity crisis. Conservationists need to understand which interventions work or fail, and how to improve them in order to invest limited funds wisely. Alternative income-generating activities (IGAs) are widely implemented within conservation and development projects, but their impact is rarely evaluated. The “ranked outcomes” evaluation methodology converts qualitative information on planned and realised outcomes into a score for comparison between projects. We test this methodology in two ways using a set of small scale IGAs implemented in communities adjacent to the Uzungwa Scarp proposed Nature Reserve in the Tanzanian Eastern Arc Mountains. The first approach used an independent evaluator and the second assessed project impacts from the perspective of target communities. Both evaluations rated Tree Planting as the most socially beneficial IGA, followed by Fish Farming. However, there was a high level of heterogeneity of perception between and within stakeholder groups (implementers and target communities), both in terms of which outcomes were most important and how well they had been achieved. Ranked outcomes emerged as a flexible framework that defines the terms of the evaluation for all stakeholders from the outset, even in cases when evaluation and clear goal-setting are omitted from original project design and planning. It can be modified for use as a component of rigorous impact assessment, to incorporate perspectives of all stakeholders, and provides important insights in data-poor situations and where baselines are not available