8,001 research outputs found

    Development of an advanced composite aileron for the L-1011 transport aircraft

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    Significant improvements in structural efficiency can be achieved by the utilization of advanced composites for construction of aircraft secondary structures. Careful evaluation of alternate designs and materials for the L-1011 advanced composite inboard aileron has led to the selection of several unique material combinations and easily manufactured structural configurations. The advanced composite aileron is a direct replacement for the metal aileron with a weight savings of 23 percent. Due to the configurational simplicity of the components within the composite aileron, and because it contains 50 percent fewer parts and fasteners than the metal aileron, it is predicted that the composite aileron will be cost competitive with the metal aileron in a production environment. Structural analysis of the composite aileron, in conjunction with the design data, concept verification, and ground tests, indicates that the composite aileron design meets or exceeds structural requirements

    Study of radiatively sustained cesium plasmas for solar energy conversion

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    The results of a study aimed at developing a high temperature solar electric converter are reported. The converter concept is based on the use of an alkali plasma to serve as both an efficient high temperature collector of solar radiation as well as the working fluid for a high temperature working cycle. The working cycle is a simple magnetohydrodynamic (MHD) Rankine cycle employing a solid electrode Faraday MHD channel. Research milestones include the construction of a theoretical model for coupling sunlight in a cesium plasma and the experimental demonstration of cesium plasma heating with a solar simulator in excellent agreement with the theory. Analysis of a solar MHD working cycle in which excimer laser power rather than electric power is extracted is also presented. The analysis predicts a positive gain coefficient on the cesium-xenon excimer laser transition

    SUSY sine-Gordon theory as a perturbed conformal field theory and finite size effects

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    We consider SUSY sine-Gordon theory in the framework of perturbed conformal field theory. Using an argument from Zamolodchikov, we obtain the vacuum structure and the kink adjacency diagram of the theory, which is cross-checked against the exact S-matrix prediction, first-order perturbed conformal field theory (PCFT), the NLIE method and truncated conformal space approach. We provide evidence for consistency between the usual Lagrangian description and PCFT on the one hand, and between PCFT, NLIE and a massgap formula conjectured by Baseilhac and Fateev, on the other. In addition, we extend the NLIE description to all the vacua of the theory. (C) 2003 Elsevier B.V. All rights reserved

    Associate to owner transition: When should a dental practice be valued?

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    One of the key issues toward a smooth transition of an associate to a practice owner is when a general dental practice is valued. This editorial explores three basic options for the timing of practice valuations and their relative favorability to the owner and associate during the transition from associate to owner

    Etiquette in making the transition into private practice

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    In this article, the author offers several tips for students who are making transition into private dental practice. It suggests not disclosing the agreed terms and information related with negotiating practice or dentist or organization. It states that the initial focus should not be concentrated on salary or compensation or practice performance indicators. It mentions that before getting into details of each opportunity, students needs to decide their priorities

    Dental student debt in the U.S.: A mountain to be scaled

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    Dental student educational debt in the United States continues to grow as a concern for both dental educators and dental students. While certainly warranted, this concern needs to be understood from the perspective of return on investment. The student debt issue remains a critical one. However, this debt is essentially “good” debt when viewed as an investment made by associates/ employees of general dental practices and general dental practice owners

    Introduction to the special issue on practice management

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    This special issue on practice management represents a labor of love from some of the key thinkers/leaders in the field of dental practice management in the United States. The topics covered in the articles are current and, in some cases, somewhat controversial. I hope the readers find the articles both stimulating and insightful

    Advanced composite aileron for L-1011 transport aircraft: Design and analysis

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    Detail design of the composite aileron has been completed. The aileron design is a multi-rib configuration with single piece upper and lower covers mechanically fastened to the substructure. Covers, front, spar and ribs are fabricated with graphite/epoxy tape or fabric composite material. The design has a weight savings of 23 percent compared to the aluminum aileron. The composite aileron has 50 percent fewer fasteners and parts than the metal aileron and is predicted to be cost competitive. Structural integrity of the composite aileron was verified by structural analysis and an extensive test program. Static, failsafe, and vibration analyses have been conducted on the composite aileron using finite element models and specialized computer programs for composite material laminates. The fundamental behavior of the composite materials used in the aileron was determined by coupon tests for a variety of environmental conditions. Critical details of the design were interrogated by static and fatigue tests on full-scale subcomponents and subassemblies of the aileron
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