Safe deployment of cluster-flying nano-satellites using relative E/I vector separation

2019 ◽  
Vol 64 (4) ◽  
pp. 964-981 ◽  
Author(s):  
Pengfei Liu ◽  
Xiaoqian Chen ◽  
Yong Zhao
Keyword(s):  
Vector Separation

scholarly journals Catalogue of Occultation Double Star Observations

1983 ◽  
Vol 62 ◽  
pp. 73-90
Keyword(s):  
Spectral Type ◽  
Position Angle ◽  
Double Star ◽  
Star Catalogue ◽  
Grade 3 ◽  
Vector Separation

The catalogue is divided into three sections: bright stars with magnitudes less than or equal to 6.7: other stars having numbers in the Smithsonian Astrophysical Star Catalogue with magnitudes greater than 6.7: and other stars with no SAO numbers, usually faint and with often only fragmentary information concerning their magnitudes or spectra.Each section has the following columns: SAO number, other name, magnitude, spectral type, run number of the observation, date in obvious coded form, grade — grade zero indicates no duplicity, grade 1 possible duplicity, grade 2 probable duplicity, and grade 3 certain duplicity. Grades are based on statements by observers. For grades other than zero the vector separation and its computed error are given in arc milliseconds. P.A. denotes the direction in which the vector separation is measured, that is the position angle on the lunar limb as modified by the slope deduced in favorable cases from the spacing of the diffraction bands on the occultation trace. The next column gives the limb slope and its error.

scholarly journals Vector separation of particles and cells using an array of slanted open cavities

Lab on a Chip ◽  
2013 ◽  
Vol 13 (6) ◽  
pp. 1086 ◽  
Author(s):  
Jorge A. Bernate ◽  
Chengxun Liu ◽  
Liesbet Lagae ◽  
Konstantinos Konstantopoulos ◽  
German Drazer
Keyword(s):  
Open Cavities ◽  
Vector Separation

Directional locking and deterministic separation in periodic arrays

2009 ◽  
Vol 627 ◽  
pp. 379-401 ◽  
Author(s):  
JOELLE FRECHETTE ◽  
GERMAN DRAZER
Keyword(s):  
External Force ◽  
Hydrodynamic Interactions ◽  
Square Lattice ◽  
Stokesian Dynamics ◽  
Particle Mobility ◽  
Periodic Arrays ◽  
Moving Particle ◽  
Dynamics Simulations ◽  
Solid Obstacles ◽  
Vector Separation

We investigate the dynamics of a non-Brownian sphere suspended in a quiescent fluid and moving through a periodic array of solid obstacles under the action of a constant external force by means of Stokesian dynamics simulations. We show that in the presence of non-hydrodynamic, short-range interactions between the solid obstacles and the suspended sphere, the moving particle becomes locked into periodic trajectories with an average orientation that coincides with one of the lattice directions and is, in general, different from the direction of the driving force. The locking angle depends on the details of the non-hydrodynamic interactions and could lead to vector separation of different species for certain orientations of the external force. We explicitly show the presence of separation for a mixture of suspended particles with different roughness, moving through a square lattice of spherical obstacles. We also present a dilute model based on the two-particle mobility and resistance functions for the collision between spheres of different sizes. This simple model predicts the separation of particles of different size and also suggests that microdevices that maximize the differences in interaction area between the different particles and the solid obstacles would be more sensitive for size separation based on non-hydrodynamic interactions.

scholarly journals The Discovery of Double Stars at Occultations

1983 ◽  
Vol 62 ◽  
pp. 63-72 ◽  
Author(s):  
David S. Evans
Keyword(s):  
Position Angle ◽  
Visual Observation ◽  
Double Star ◽  
Double Stars ◽  
Photoelectric Observations ◽  
Vector Separation ◽  
Successful Observation

When systematic photoelectric observations of occultations were started some dozen years ago it was realised that they yielded a significant crop of double star discoveries and observations. The limitations of the method were well recognised: only about ten percent of the area of the sky would ever be available and one could not choose which stars to be observed. Moreover the data obtained from a successful observation of a double star are less comprehensive than the normal visual observation. The result is the vector separation or the true separation projected along a line perpendicular to the actual lunar limb, that is the position angle of the point of occultation modified by the slope of the limb at that point.

Weak magnetohydrodynamic turbulence and intermittency

2015 ◽  
Vol 770 ◽  
Author(s):  
R. Meyrand ◽  
K. H. Kiyani ◽  
S. Galtier
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Three Dimensional ◽  
Leading Order ◽  
Magnetohydrodynamic Turbulence ◽  
Asymptotic Regime ◽  
Resonant Interactions ◽  
Vector Separation ◽  
Parallel Current

Three-dimensional numerical simulation is used to investigate intermittency in incompressible weak magnetohydrodynamic turbulence with a strong uniform magnetic field $\boldsymbol{b}_{\mathbf{0}}$ and zero cross-helicity. At leading order, this asymptotic regime is achieved via three-wave resonant interactions with the scattering of a wave on a 2D mode for which $k_{\Vert }=0$. When the interactions with the 2D modes are artificially reduced, we show numerically that the system exhibits an energy spectrum with $k_{\bot }^{-3/2}$, whereas the expected exact solution with $k_{\bot }^{-2}$ is recovered with the full nonlinear system. In the latter case, strong intermittency is found when the vector separation of structure functions is taken transverse to $\boldsymbol{b}_{\mathbf{0}}$. This result may be explained by the influence of the 2D modes whose regime belongs to strong turbulence. In addition to shedding light on the origin of this intermittency, we derive a log-Poisson law, ${\it\zeta}_{p}=p/8+1-(1/4)^{p/2}$, which fits the data perfectly and highlights the important role of parallel current sheets.

scholarly journals Occultation Binaries Observed from KPNO: Astrometry Corrections Using the Observed Rate of Lunar Motion

1992 ◽  
Vol 135 ◽  
pp. 570-572
Author(s):  
Paul C. Schmidtke
Keyword(s):  
Binary Stars ◽  
Binary Star ◽  
Angular Separation ◽  
Position Angle ◽  
Background Intensity ◽  
Minimum Number ◽  
The Difference ◽  
Predicted Values ◽  
Occultation Data ◽  
Vector Separation

Lunar occultation data often are reduced by means of a multiparameter least-squares fitting routine. For binary stars the minimum number of free parameters is five: the time of geometric occultation for each star, the intensity of each component, and the background intensity. From these values the magnitude difference between components can be calculated as well as the angular separation of the binary in the direction perpendicular to the lunar limb (i.e. the lunar position angle). If the observed rate of motion of the lunar limb can be determined as an additional free parameter, then the difference between observed and predicted values can be interpreted in terms of a local lunar slope. Therefore, in principal the observed rate of motion can be used to correct the vector separation — both angular separation and direction — of the binary. In this paper four occultation binaries observed from KPNO are examined to determine whether binary-star astrometry can be improved using these corrections.

scholarly journals Discussions on the Processing of the Multi-Component Seismic Vector Field

2019 ◽  
Vol 9 (9) ◽  
pp. 1770
Author(s):  
Wang ◽  
Wang ◽  
Sun ◽  
Li
Keyword(s):  
Vector Field ◽  
Seismic Data ◽  
Main Stream ◽  
Processing Methods ◽  
Compressional Waves ◽  
Vector Processing ◽  
Information Research ◽  
The Individual ◽  
Processing Techniques ◽  
Vector Separation

Multi-component seismic data contain a great deal of vector field information that reflects the situation of the underground medium. However, the processing methods used for multi-component seismic data are still being developed, and effectively retaining and using this information is the difficulty and the focus of the task. Currently, the main-stream processing techniques of multi-component seismic data treat the individual components independently as a scalar field; in this way, they do not excavate the vector features of the wavefield, thus restricting the potential utilities of the effective information. Research into processing methods that are suitable for use with the vector field, which can better retain and use the orientations and the relative amplitude relationship between multi-component seismic data, is urgently needed and represent an important direction for the current development of multi-component seismic data processing techniques. In this paper, we introduce and summarize several existing vector pre-processing techniques, including polarization filtering, de-noising using vector order statistics, group sparse representation, and vector separation of compressional waves and shear waves, to help scholars develop more effective vector field processing methods and to promote the development of vector processing techniques for multi-component seismic data.

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