5,721 research outputs found
Final Report: Wall Effects in Cavity Flows
The wall effects in cavity flows past an arbitrary two-dimensional body is investigated for both pure-drag and lifting cases based on an inviscid nonlinear flow theory. The over-all features of various theoretical flow models for inviscid cavity flows under the wall effects are discussed from the general momentum consideration in comparison with typical viscous, incompressible wake flows in a channel. In the case of pure drag cavity flows, three theoretical models in common use, namely, the open-wake, Riabouchinsky and re-entrant jet models, are applied to evaluate the solution. Methods of numerical computation are discussed for bodies of arbitrary shape, and are carried out in detail for wedges of all angles. The final numerical results are compared between the different flow models, and the differences pointed out. Further analysis of the results has led to development of several useful formulas for correcting the wall effect. In the lifting flow case, the wall effect on the pressure and hydrodynamic forces acting on arbitrary body is formulated for the choked cavity flow in a closed water tunnel of arbitrary shape, and computed for the flat plate with a finite cavity in a straight tunnel
Tradeoffs in manipulator structure and control. Part 1: Summary
The study of various aspects of manipulator design and control is summarized, focusing on the interaction of the structure's flexible dynamics and the dynamics of the joint control system, including specific information on modeling and design, modal analysis and control, and the flexible manipulator analysis computer program, FMAP
EC68-1814 Fire Blight of Apples and Pears
Extension Circular 68-1814 deals with fire blight. Fire blight is a common and frequently destructive bacterial disease of certain plants belonging to the rose family
Contracture of the Infraspinatus Muscle in the Dog
A tentative diagnosis of contracture of the infraspinatus muscle was made in a dog with a foreleg shoulder lameness causing a positional deformity and characteristic abnormal gait in the affected limb. Contracture of the infraspinatus muscle most commonly involves hunting breeds, particularly actively working dogs
Academic Perspectives on Agribusiness: An International Survey
The IFAMR is published by (IFAMA) the International Food and Agribusiness Management Review. www.ifama.orgpromotion and tenure, agribusiness, teaching, grantsmanship, research, Agribusiness, Institutional and Behavioral Economics, Productivity Analysis, Teaching/Communication/Extension/Profession, Q130,
The bisymplectomorphism group of a bounded symmetric domain
An Hermitian bounded symmetric domain in a complex vector space, given in its
circled realization, is endowed with two natural symplectic forms: the flat
form and the hyperbolic form. In a similar way, the ambient vector space is
also endowed with two natural symplectic forms: the Fubini-Study form and the
flat form. It has been shown in arXiv:math.DG/0603141 that there exists a
diffeomorphism from the domain to the ambient vector space which puts in
correspondence the above pair of forms. This phenomenon is called symplectic
duality for Hermitian non compact symmetric spaces.
In this article, we first give a different and simpler proof of this fact.
Then, in order to measure the non uniqueness of this symplectic duality map, we
determine the group of bisymplectomorphisms of a bounded symmetric domain, that
is, the group of diffeomorphisms which preserve simultaneously the hyperbolic
and the flat symplectic form. This group is the direct product of the compact
Lie group of linear automorphisms with an infinite-dimensional Abelian group.
This result appears as a kind of Schwarz lemma.Comment: 19 pages. Version 2: minor correction
Spitzer Observations of the HII Region NGC 2467: An Analysis of Triggered Star Formation
We present new Spitzer Space Telescope observations of the region NGC 2467,
and use these observations to determine how the environment of an HII region
affects the process of star formation. Our observations comprise IRAC (3.6,
4.5, 5.8, and 8.0 um) and MIPS (24 um) maps of the region, covering
approximately 400 square arcminutes. The images show a region of ionized gas
pushing out into the surrounding molecular cloud, powered by an O6V star and
two clusters of massive stars in the region. We have identified as candidate
Young Stellar Objects (YSOs) 45 sources in NGC 2467 with infrared excesses in
at least two mid-infrared colors. We have constructed color-color diagrams of
these sources and have quantified their spatial distribution within the region.
We find that the YSOs are not randomly distributed in NGC 2467; rather, over
75% of the sources are distributed at the edge of the HII region, along
ionization fronts driven by the nearby massive stars. The high fraction of YSOs
in NGC 2467 that are found in proximity to gas that has been compressed by
ionization fronts supports the hypothesis that a significant fraction of the
star formation in NGC 2467 is triggered by the massive stars and the expansion
of the HII region. At the current rate of star formation, we estimate at least
25-50% of the total population of YSOs formed by this process.Comment: Accepted to the Astrophysical Journal, set to appear in Volume 701;
18 pages, 13 figures, 4 tables. This version reflects a few major changes
made in the accepted version, including new figure
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Comparative study of design: application to Engineering Design
A recent exploratory study examines design processes across domains and compares them. This is achieved through a series of interdisciplinary, participative workshops. A systematic framework is used to collect data from expert witnesses who are practising designers across domains from engineering through architecture to product design and fashion, including film production, pharmaceutical drugs, food, packaging, graphics and multimedia and software. Similarities and differences across domains are described which indicate the types of comparative analysis we have been able to do from our data. The paper goes further and speculates on possible lessons for selected areas of engineering design which can be drawn from comparison with processes in other domains. As such this comparative design study offers the potential for improving engineering design processes. More generally it is a first step in creating a discipline of comparative design which aims to provide a new rich picture of design processes
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