1,807 research outputs found
Prolate spheroidal slosh model for fluid motion
Mathematical model, designed for zero gravity conditions, analyzes dynamic effects of large amplitude fluid motion interior to a rigid body. It has two advantages over other mathematical models: (1) constrains slosh motion to given region in natural manner, and (2) allows equilibrium position of slosh mass to be anywhere on slosh surface
Kinematic capability in the SVDS
The details of the Remote Manipulator System kinematic model implemented into the Space Vehicle Dynamics Simulation are given. Detailed engineering flow diagrams and definitions of terms are included
RMS massless arm dynamics capability in the SVDS
The equations of motion for the remote manipulator system, assuming that the masses and inertias of the arm can be neglected, are developed for implementation into the space vehicle dynamics simulation (SVDS) program for the Orbiter payload system. The arm flexibility is incorporated into the equations by the computation of flexibility terms for use in the joint servo model. The approach developed in this report is based on using the Jacobian transformation matrix to transform force and velocity terms between the configuration space and the task space to simplify the form of the equations
The GOAL-to-HAL/S translator specification
The specification sets forth a technical framework within which to deal with the transfer of specific GOAL features to HAL/S. Key technical features of the translator are described which communicate with the data bank, handle repeat statements, and deal with software interrupts. GOAL programs, databank information, and GOAL system subroutines are integrated into one GOAL in HAL/S. This output is fully compatible HAL/S source ready for insertion into the HAL/S compiler. The Translator uses a PASS1 to establish all the global data needed for the HAL/S output program. Individual GOAL statements are translated in PASS2. The specification document makes extensive use of flowcharts to specify exactly how each variation of each GOAL statement is to be translated. The specification also deals with definitions and assumptions, executive support structure and implementation. An appendix, entitled GOAL-to-HAL Mapping, provides examples of translated GOAL statements
Maxwell's Equations in a Uniformly Rotating Dielectric Medium and the Wilson-Wilson Experiment
This note offers a conceptually straightforward and efficient way to
formulate and solve problems in the electromagnetics of moving media based on a
representation of Maxwell's equations in terms of differential forms on
spacetime together with junction conditions at moving interfaces. This
framework is used to address a number of issues that have been discussed
recently in this journal about the theoretical description underlying the
interpretation of the Wilson-Wilson experiment.Comment: 16 pages, 2 figure
On the Spinning Motion of the Hovering Magnetic Top
In this paper we analyze the spinning motion of the hovering magnetic top. We
have observed that its motion looks different from that of a classical top. A
classical top rotates about its own axis which precesses around a vertical
fixed external axis. The hovering magnetic top, on the other hand, has its axis
slightly tilted and moves rigidly as a whole about the vertical axis. We call
this motion synchronous, because in a stroboscopic experiment we see that a
point at the rim of the top moves synchronously with the top axis. We show that
the synchronous motion may be attributed to a small deviation of the magnetic
moment from the symmetry axis of the top. We calculate the minimum angular
velocity required for stability in terms of the moments of inertia and magnetic
field and show that it is different from that of a classical top. We also give
experimental results that were taken with a top whose moment of inertia can be
changed. These results show very good agreement with our calculations.Comment: 19 pages (including 3 figures named fig1.eps-fig3.eps), uses amssymb,
epsf and amsbsy (AMSLaTeX
The affine preservers of non-singular matrices
When K is an arbitrary field, we study the affine automorphisms of M_n(K)
that stabilize GL_n(K). Using a theorem of Dieudonn\'e on maximal affine
subspaces of singular matrices, this is easily reduced to the known case of
linear preservers when n>2 or #K>2. We include a short new proof of the more
general Flanders' theorem for affine subspaces of M_{p,q}(K) with bounded rank.
We also find that the group of affine transformations of M_2(F_2) that
stabilize GL_2(F_2) does not consist solely of linear maps. Using the theory of
quadratic forms over F_2, we construct explicit isomorphisms between it, the
symplectic group Sp_4(F_2) and the symmetric group S_6.Comment: 13 pages, very minor corrections from the first versio
Topological aspect of graphene physics
Topological aspects of graphene are reviewed focusing on the massless Dirac
fermions with/without magnetic field. Doubled Dirac cones of graphene are
topologically protected by the chiral symmetry. The quantum Hall effect of the
graphene is described by the Berry connection of a manybody state by the filled
Landau levels which naturally possesses non-Abelian gauge structures. A generic
principle of the topologically non trivial states as the bulk-edge
correspondence is applied for graphene with/without magnetic field and explain
some of the characteristic boundary phenomena of graphene.Comment: 12 pages, 8 figures. Proceedings for HMF-1
Comment on "Geometric phase of the gyromotion for charged particles in a time-dependent magnetic field" [Phys. Plasmas 18, 072505 (2011)]
The geometric analysis of the gyromotion for charged particles in a
time-dependent magnetic field by J. Liu and H. Qin [Phys. Plasmas 18, 072505
(2011)] is reformulated in terms of the spatial angles that represent the
instantaneous orientation of the magnetic field. This new formulation, which
includes the equation of motion for the pitch angle, clarifies the
decomposition of the gyroangle-averaged equation of motion for the gyrophase
into its dynamic and geometric contributions.Comment: 4 page
On the Theory of Superfluidity in Two Dimensions
The superfluid phase transition of the general vortex gas, in which the
circulations may be any non-zero integer, is studied. When the net circulation
of the system is not zero the absence of a superfluid phase is shown. When the
net circulation of the vortices vanishes, the presence of off-diagonal long
range order is demonstrated and the existence of an order parameter is
proposed. The transition temperature for the general vortex gas is shown to be
the Kosterlitz---Thouless temperature. An upper bound for the average vortex
number density is established for the general vortex gas and an exact
expression is derived for the Kosterlitz---Thouless ensemble.Comment: 22 pages, one figure, written in plain TeX, published in J. Phys. A24
(1991) 502
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