9,844 research outputs found

    Magnetoresistor monitors relay performance

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    Magnetoresistor monitors the action of relays without disturbing circuit parameters or degrading relay performance. The magnetoresistor measures the relay magnetic flux produced under transient conditions to establish the characteristic signature of the relay

    Test instrumentation evaluates electrostatic hazards in fluid system

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    RJ-1 fuel surface potential is measured with a probe to determine the degree of hazard originating from static electricity buildup in the hydraulic fluid. The probe is mounted in contact with the fluid surface and connected to an electrostatic voltmeter

    The reaction pi N -> pi pi N in chiral effective field theory with explicit Delta(1232) degrees of freedom

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    The reaction pi N -> pi pi N is studied at tree level up to next-to-leading order in the framework of manifestly covariant baryon chiral perturbation theory with explicit Delta(1232) degrees of freedom. Using total cross section data to determine the relevant low-energy constants, predictions are made for various differential as well as total cross sections at higher energies. A detailed comparison of results based on the heavy-baryon and relativistic formulations of chiral perturbation theory with and without explicit Delta degrees of freedom is given.Comment: 30 pages, 13 figure

    The Rating Agencies: Where We Have Been and Where Do We Go From Here?

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    The credit rating agencies are supposed to be gatekeepers to the public securities markets. As “gatekeepers,” they are reputational intermediaries in the investment process. Other gatekeepers include: independent auditors, credit rating agencies, securities analysts, investment bankers, and attorneys. The function of these reputational intermediaries is to act as neutral third party advisors to the investment process. While these intermediaries are paid for their opinions by one or more parties to a transaction, in theory the opinions will be neutral. This is due to the thought that any resulting reputational damage from non-neutral opinions would severely damage long-term profitability, in exchange for mere short-term profits. The rating agencies are very different from other gatekeepers, as they exist in a position of profitable limbo somewhere between market journalist and state authority. They claim they are merely reputational intermediaries sought by numerous market participants for neutral opinions on the safety of securities products. At the same time, they uniquely occupy a niche where government regulation mandates that market participants utilize their ratings; they are, in fact, selling compliance with official regulation. This puts them in a position of incredible power and provides them with little accountability. With the recent explosion of unregulated securities and the ensuing near collapse of the financial markets, it seems these agencies are perhaps not gatekeepers, but rather mechanics, greasing the wheels of a giant runaway train of dangerous financial products. This article will explore the rating agencies\u27 role in this recent crisis and will discuss the need for increased regulation or liability for the agencies to function effectively. This comment will ask what is the most realistic way to accomplish this. Part II is an introduction to who the rating agencies are and what they do. Part III looks at how we got where we are and explores two common criticisms against the agencies that even their former employees attest to. Part IV navigates recent responses, both by the agencies to criticism and by the government through the SEC. Part V looks at past liability exposure to the agencies and common defenses they have raised. There will also be some discussion of whether legislation passed has changed anything, as well as a look at a common barrier to litigation against the agencies. Finally, Part VI offers the author\u27s own opinions on where we go from here

    Use of computer-aided analysis techniques for cover type mapping in areas of mountainous terrain

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    There are no author-identified significant results in this report

    Design, Fabrication and Test of Composite Curved Frames for Helicopter Fuselage Structure

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    Aspects of curved beam effects and their importance in designing composite frame structures are discussed. The curved beam effect induces radial flange loadings which in turn causes flange curling. This curling increases the axial flange stresses and induces transverse bending. These effects are more important in composite structures due to their general inability to redistribute stresses by general yielding, such as in metal structures. A detailed finite element analysis was conducted and used in the design of composite curved frame specimens. Five specimens were statically tested and compared with predicted and test strains. The curved frame effects must be accurately accounted for to avoid premature fracture; finite element methods can accurately predict most of the stresses and no elastic relief from curved beam effects occurred in the composite frames tested. Finite element studies are presented for comparative curved beam effects on composite and metal frames

    Complex-mass renormalization in hadronic EFT: applicability at two-loop order

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    We discuss the application of the complex-mass scheme to multi-loop diagrams in hadronic effective field theory by considering as an example a two-loop self-energy diagram. We show that the renormalized two-loop diagram satisfies the power counting.Comment: 8 pages, 2 figures, version accepted for publication in EPJ

    Elastic pion-nucleon scattering in chiral perturbation theory: A fresh look

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    Elastic pion-nucleon scattering is analyzed in the framework of chiral perturbation theory up to fourth order within the heavy-baryon expansion and a covariant approach based on an extended on-mass-shell renormalization scheme. We discuss in detail the renormalization of the various low-energy constants and provide explicit expressions for the relevant β\beta-functions and the finite subtractions of the power-counting breaking terms within the covariant formulation. To estimate the theoretical uncertainty from the truncation of the chiral expansion, we employ an approach which has been successfully applied in the most recent analysis of the nuclear forces. This allows us to reliably extract the relevant low-energy constants from the available scattering data at low energy. The obtained results provide a clear evidence that the breakdown scale of the chiral expansion for this reaction is related to the Δ\Delta-resonance. The explicit inclusion of the leading contributions of the Δ\Delta-isobar is demonstrated to substantially increase the range of applicability of the effective field theory. The resulting predictions for the phase shifts are in an excellent agreement with the ones from the recent Roy-Steiner-equation analysis of pion-nucleon scattering
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