25,075 research outputs found
Flight and wind-tunnel comparisons of the inlet-airframe interaction of the F-15 airplane
The design of inlets and nozzles and their interactions with the airplane which may account for a large percentage of the total drag of modern high performance aircraft is discussed. The inlet/airframe interactions program and the flight tests conducted is described. Inlet drag and lift data from a 7.5% wind-tunnel model are compared with data from an F-15 airplane with instrumentation to match the model. Pressure coefficient variations with variable cowl angles, capture ratios, examples of flow interactions and angles of attack are for Mach numbers of 0.6, 0.9, 1.2, and 1.5 are presented
Multivariate Time Series Approaches To Analysing The Northern Irish Conflict: Lessons For Future Sub-State Conflict Control
This paper is essentially an introduction to the use of multivariate time series analyses of the Northern Irish conflict from 1969-1981.It draws on the conceptual work of Paul Smoker to describe systemic conflict relationships between all the parties to this conflict. Using some of the most comprehensive statistical documentation ever compiled on an internal conflict, the authors present an innovative methodology to show the highly structured nature of this conflict over a long period of time. The paper and its ancillary web sites present not only the data archive, but also the univariate, bivariate and multivariate time series programmes used to make the analyses. The outputs are presented in the form of descriptions of associated influence or ‘systemograms’ which can describe the dynamic and changing conflict ecology where apparently disparate conflict behaviour such as house searches, plastic bullet firings and the killing of military personnel, are highly correlated. Measures of autocorrelation are used to suggest a loss of freedom in the actions of particular conflict participants. Particular attention is given to the use of “less-lethal weapons” and their impact on overall conflict dynamics. What emerges is that sectarian killings form a distinct conflict susbset, whereas the counter-insurgency behaviour of the state security forces act as a conflict driver, ratchet ting up the conflict as each more severe phase of the counterinsurgency programme is introduced. The paper attempts to introduce a whole systems conflict approach which is both dynamic and puzzling, since in many respects it indicates cooperation between the various participants to carry on the conflict at a systemic level. The provisional lessons of this study are that sub-state conflict control measures can prove dysfunctional. The work is very much a case of research in progress and the findings remain tentative. We are re-introducing it at this time since it does open the prospect of repeating the research methodology in other sub-state conflicts such as Israel and Iraq, if reliable data were ever to become available
High spatial resolution observations of CUDSS14A: a SCUBA-selected ultraluminous galaxy at high redshift
The definitive version is available at www.blackwell-synergy.com '. Copyright Blackwell Publishing DOI : 10.1046/j.1365-8711.2000.03822.xWe present a high-resolutionmillimetre interferometric image of the brightest SCUBA- selected galaxy from the Canada-UK deep SCUBA survey (CUDSS). We make a very clear detection at 1.3 mm, but fail to resolve any structure in the source.Peer reviewe
Remotely controlled mirror of variable geometry for small angle x-ray diffraction with synchrotron radiation
A total-reflecting mirror of 120-cm length was designed and built to focus synchrotron radiation emanating from the electron-positron storage ring at the Stanford Linear Accelerator Center (SPEAR). The reflecting surface is of
unpolished float glass. The bending and tilt mechanism allows very fine control of the curvature and selectability of the critical angle for wavelengths ranging from 0.5 to 3.0 Å. Elliptical curvature is used to minimize aberrations. The mirror is placed asymmetrically onto the ellipse so as to achieve a tenfold demagnification of the source. The bending mechanism reduces nonelastic
deformation (flow) and minimizes strains and stresses in the glass despite its length. Special design features assure stability of the focused image. The mirror
reduces the intensity of shorter wavelength harmonics by a factor of approximately 100
Boxfishes (Teleostei: Ostraciidae) as a model system for fishes swimming with many fins: kinematics
Swimming movements in boxfishes were much more
complex and varied than classical descriptions indicated.
At low to moderate rectilinear swimming speeds
(<5 TL s^(-1), where TL is total body length), they were
entirely median- and paired-fin swimmers, apparently
using their caudal fins for steering. The pectoral and
median paired fins generate both the thrust needed for
forward motion and the continuously varied, interacting
forces required for the maintenance of rectilinearity. It
was only at higher swimming speeds (above 5 TL s^(-1)), when
burst-and-coast swimming was used, that they became
primarily body and caudal-fin swimmers. Despite their
unwieldy appearance and often asynchronous fin beats,
boxfish swam in a stable manner. Swimming boxfish used
three gaits. Fin-beat asymmetry and a relatively nonlinear
swimming trajectory characterized the first gait
(0–1 TL s^(-1)). The beginning of the second gait (1–3 TL s^(-1))
was characterized by varying fin-beat frequencies and
amplitudes as well as synchrony in pectoral fin motions.
The remainder of the second gait (3–5 TL s^(-1)) was
characterized by constant fin-beat amplitudes, varying finbeat
frequencies and increasing pectoral fin-beat
asynchrony. The third gait (>5 TL s^(-1)) was characterized
by the use of a caudal burst-and-coast variant. Adduction
was always faster than abduction in the pectoral fins.
There were no measurable refractory periods between
successive phases of the fin movement cycles. Dorsal and
anal fin movements were synchronized at speeds greater
than 2.5 TL s^(-1), but were often out of phase with pectoral
fin movements
Bulk and shear relaxation in glasses and highly viscous liquids
The ratio between the couplings of a relaxational process to compression and
shear, respectively, is calculated in the Eshelby picture of structural
rearrangements within a surrounding elastic matrix, assuming a constant density
of stable structures in distortion space. The result is compared to
experimental data for the low-temperature tunneling states in glasses and to
Prigogine-Defay data at the glass transition from the literature.Comment: 6 pages, 2 figures, 53 references; version after understanding the
Prigogine-Defay ratio at the glass transition in the accompanying paper
arXiv:1203.3555 [cond-mat.dis-nn
PCV92 THE HEALTH AND ECONOMIC IMPACT OF SWITCHING FROM ATORVASTATIN TO GENERIC SIMVASTATIN IN BELGIUM
A study of the potential impacts of space utilization
Because the demand for comprehensive impact analysis of space technologies will increase with the use of space shuttles, the academic social sciences/humanities community was surveyed in order to determine their interests in space utilization, to develop a list of current and planned courses, and to generate a preliminary matrix of relevant social sciences. The academic scope/focus of a proposed social science space-related journal was identified including the disciplines which should be represented in the editorial board/reviewer system. The time and funding necessary to develop a self-sustaining journal were assessed. Cost income, general organizational structure, marking/distribution and funding sources were analyzed. Recommendations based on the survey are included
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