Aerodynamic interference effects on tilting proprotor aircraft

The Green's function method was used to study tilting proprotor aircraft aerodynamics with particular application to the problem of the mutual interference of the wing-fuselage-tail-rotor wake configuration. While the formulation is valid for fully unsteady rotor aerodynamics, attention was directed to steady state aerodynamics, which was achieved by replacing the rotor with the actuator disk approximation. The use of an actuator disk analysis introduced a mathematical singularity into the formulation; this problem was studied and resolved. The pressure distribution, lift, and pitching moment were obtained for an XV-15 wing-fuselage-tail rotor configuration at various flight conditions. For the flight configurations explored, the effects of the rotor wake interference on the XV-15 tilt rotor aircraft yielded a reduction in the total lift and an increase in the nose-down pitching moment. This method provides an analytical capability that is simple to apply and can be used to investigate fuselage-tail rotor wake interference as well as to explore other rotor design problem areas

Improvements in Space Geodesy Data Discovery at the CDDIS

The Crustal Dynamics Data Information System (CDDIS) supports data archiving and distribution activities for the space geodesy and geodynamics community. The main objectives of the system are to store space geodesy and geodynamics related data products in a central data bank. to maintain information about the archival of these data, and to disseminate these data and information in a timely manner to a global scientific research community. The archive consists of GNSS, laser ranging, VLBI, and DORIS data sets and products derived from these data. The CDDIS is one of NASA's Earth Observing System Data and Information System (EOSDIS) distributed data centers; EOSDIS data centers serve a diverse user community and arc tasked to provide facilities to search and access science data and products. Several activities are currently under development at the CDDIS to aid users in data discovery, both within the current community and beyond. The CDDIS is cooperating in the development of Geodetic Seamless Archive Centers (GSAC) with colleagues at UNAVCO and SIO. TIle activity will provide web services to facilitate data discovery within and across participating archives. In addition, the CDDIS is currently implementing modifications to the metadata extracted from incoming data and product files pushed to its archive. These enhancements will permit information about COOlS archive holdings to be made available through other data portals such as Earth Observing System (EOS) Clearinghouse (ECHO) and integration into the Global Geodetic Observing System (GGOS) portal

Voters, legislators and bureaucracy: Institutional design in the public sector

The purpose of this paper is to outline a theory of representative democracy which explains why rational actors construct an excessively bureaucratized government. We define excessive bureaucratization as the selection of an inefficient production technology for the public sector, characterized by relative factor proportions that entail more bureaucracy than the proportions that would minimize total costs. Thus, the question of excessive bureaucracy is related to but conceptually different from whether a particular policy is worthwhile. Furthermore, it presumes a concern more fundamental than the observation that implementing a public policy inevitably requires the expenditure of scarce resources

Majority rule models and legislative elections

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New calibrations and time stability of the response of the INTERCAST CR-39

We present new calibrations of different production batches (from 1989 to 1999) of the INTERCAST CR-39, using the BNL-AGS 1 A GeV iron beam. The comparison with previous results, obtained with the 158 A GeV lead beam from the CERN-SPS shows that, while each production batch has a different calibration curve (mainly due to minor differences in the production conditions), the aging effect is negligible. We also tested the dependence of the CR-39 response from the time elapsed between exposure and analysis (fading effect). The fading effect, if present, is less than 10%. It may be compatible with the experimental uncertainties on the bulk etching rate vB.Comment: 9 pages, 4 EPS figures, .pdf file. Talk presented by M. Giorgini at the 20 Int. Conf. on Nuclear Tracks in Solids, Portoroz (Slovenia), Aug 28-Sep 1, 200

Remediation of Contaminated Sites — Case Histories

In this paper, two major remediation projects located in the German Ruhr District will be introduced. The key to an effective land re-utilization plan is a harmonized management of ground investigation, risk assessment and clean-up strategies. Geotechnical and hydrogeological techniques, as well as economical risks involved in the recycling of industrial wasteland will be discussed. Criteria which led to the acceptance of certain remediation techniques will be reflected and their validity will be examined. It will be analyzed whether the projected performance objectives have been met and the demands of both, the investors and the environmental protection agencies have been satisfied. Special attention will be paid to the cost-effectiveness of the remediation strategies proposed

The Economics of Boxing Regulation in California

Boxing was legalized in California through a statewide referendum in 1924that simultaneously set up a regulatory authority with broad powers to control the industry. This study examines the economic performance of the boxing industry, the case for regulatory intervention, and the effects of the specific kinds of regulatory rules that have been imposed. While regulation in California is widely believed to be an important factor explaining the unusually low rates of death and injury in boxing matches in the state, it is also shown to have anticompetitive effects. Several changes in regulatory procedures are proposed that would not reduce the extent to which regulation protects boxers, but would serve to enhance the competitive performance of the industry

Design of a flight control architecture using a non-convex bundle method

We design a feedback control architecture for longitudinal flight of an aircraft. The multi-level architecture includes the flight control loop to govern the short term dynamics of the aircraft, and the autopilot to control the long term modes. Using H1 performance and robustness criteria, the problem is cast as a non-convex and non-smooth optimization program. We present a non-convex bundle method, prove its convergence, and show that it is apt to solve the longitudinal flight control problem