340,690 research outputs found

    Application of shape grammar theory to underground rail station design and passenger evacuation

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    This paper outlines the development of a computer design environment that generates station ‘reference’ plans for analysis by designers at the project feasibility stage. The developed program uses the theoretical concept of shape grammar, based upon principles of recognition and replacement of a particular shape to enable the generation of station layouts. The developed novel shape grammar rules produce multiple plans of accurately sized infrastructure faster than by traditional means. A finite set of station infrastructure elements and a finite set of connection possibilities for them, directed by regulations and the logical processes of station usage, allows for increasingly complex composite shapes to be automatically produced, some of which are credible station layouts at ‘reference’ block plan level. The proposed method of generating shape grammar plans is aligned to London Underground standards, in particular to the Station Planning Standards and Guidelines 5th edition (SPSG5 2007) and the BS-7974 fire safety engineering process. Quantitative testing is via existing evacuation modelling software. The prototype system, named SGEvac, has both the scope and potential for redevelopment to any other country’s design legislation

    Bell v. Cheswick Generating Station

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    ABSTRACT This case addressed the issue of whether the Clean Air Act (CAA) preempts state law tort claims of private landowners brought in the state where emissions are occurring. Additionally, the case determined whether the political question doctrine barred the complaint as a policy-making decision constitutionally allocated to the U.S. Congress. The court decided that the cooperative purpose of the CAA is not frustrated when actions are brought under the law of the pollution’s source state, rather than the state law of affected parties. The federal regulations serve as a floor that state law may exceed but not lower. The court also determined that no court has ever held, under the political question doctrine, that the legislative branch carries constitutional authority to redress private property rights regarding air pollution, so the claim was constitutional. It was thus proper for the Bell parties to seek redress for individual tort damages under the CAA

    Evaluation of an operating MOD-OA 200 kW wind turbine blade

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    Operating loads and structural damage were monitored during operation of the MOD-OA electric generating system. The turbine was damaged locally between stations 48 and 125 after 2.8 million rotations. Loads due to degraded yaw stiffness and fretting at rib station 48 were identified as primary to this distress. The repaired blades operated an additional 4.8 million rotations without problems

    VHF downline communication system for SLAR data

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    A real time VHF downlink communication system is described for transmitting side-looking airborne radar (SLAR) data directly from an aircraft to a portable ground/shipboard receiving station. Use of this receiving station aboard the U.S. Coast Guard icebreaker Mackinaw for generating real-time photographic quality radar images is discussed. The system was developed and demonstrated in conjunction with the U.S Coast Guard and NOAA National Weather Service as part of the Project Icewarn all weather ice information system for the Great Lakes Winter Navigation Program

    Conceptual design and integration of a space station resistojet propulsion assembly

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    The resistojet propulsion module is designed as a simple, long life, low risk system offering operational flexibility to the space station program. It can dispose of a wide variety of typical space station waste fluids by using them as propellants for orbital maintenance. A high temperature mode offers relatively high specific impulse with long life while a low temperature mode can propulsively dispose of mixtures that contain oxygen or hydrocarbons without reducing thruster life or generating particulates in the plume. A low duty cycle and a plume that is confined to a small aft region minimizes the impacts on the users. Simple interfaces with other space station systems facilitate integration. It is concluded that there are no major obstacles and many advantages to developing, installing, and operating a resistojet propulsion module aboard the Initial Operational Capability (IOC) space station

    Advancing automation and robotics technology for the Space Station and for the US economy. Volume 1: Executive overview

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    In response to Public Law 98-371, dated July 18, 1984, the NASA Advanced Technology Advisory Committee has studied automation and robotics for use in the Space Station. The Executive Overview, Volume 1 presents the major findings of the study and recommends to NASA principles for advancing automation and robotics technologies for the benefit of the Space Station and of the U.S. economy in general. As a result of its study, the Advanced Technology Advisory Committee believes that a key element of technology for the Space Station is extensive use of advanced general-purpose automation and robotics. These systems could provide the United States with important new methods of generating and exploiting space knowledge in commercial enterprises and thereby help preserve U.S. leadership in space

    Dynamic safety assessment of a nonlinear pumped-storage generating system in a transient process

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    This paper focuses on a pumped-storage generating system with a reversible Francis turbine and presents an innovative framework for safety assessment in an attempt to overcome their limitations. Thus the aim is to analyze the dynamic safety process and risk probability of the above nonlinear generating system. This study is carried out based on an existing pumped-storage power station. In this paper we show the dynamic safety evaluation process and risk probability of the nonlinear generating system using Fisher discriminant method. A comparison analysis for the safety assessment is performed between two different closing laws, namely the separate mode only to include a guide vane and the linkage mode that includes a guide vane and a ball valve. We find that the most unfavorable condition of the generating system occurs in the final stage of the load rejection transient process. It is also demonstrated that there is no risk to the generating system with the linkage mode but the risk probability of the separate mode is 6 percent. The results obtained are in good agreement with the actual operation of hydropower stations. The developed framework may not only be adopted for the applications of the pumped-storage generating system with a reversible Francis turbine but serves as the basis for the safety assessment of various engineering applications.National Natural Science Foundation of ChinaFundamental Research Funds for the Central UniversitiesScientific research funds of Northwest A&F UniversityScience Fund for Excellent Young Scholars from Northwest A&F University and Shaanxi Nova progra

    Motion for a "Just Transition" in Response to Closure of the Mohave Generating Station

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    Mohave Generating Station closed on December 31, 2005. The Grand Canyon Trust organized an innovative proposal to the California Public Utility Commission to direct the use of revenues from the sale of Mohave's sulfur credits to benefit tribal communities affected by the closure of Black Mesa coal mine that supplied coal to the power plant. The "Just Transition Coalition" is engaged an developing alternative proposals that would reinvest approximately $30 million in annual revenues from the sale of sulfur credits with other sources such as clean and renewable energy bonds to create equity ownership options for tribes in wind and solar projects.Founded by an alliance of Navajo and Hopi interest groups, the Trust, and Sierra Club, the Just Transition Coalition is now supported by dozens of chapters, villages, and an increasing number of tribally elected officials
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