Diagnosis of Vertical Motion from VAS Retrievals

This paper proposes a body weight support (BWS) system with a series elastic actuator (SEA) to facilitate walking assistance and motor relearning during gait rehabilitation. This system comprises the following: a mobile platform that ensures movement of the system on the ground, a BWS mechanism with an SEA that is capable of providing the desired unloading force, and a pelvic brace to smooth the pelvis motions. The control of the body weight support is realized by an active weight-offload method, and a dynamic model of the BWS system with offload mass of a human is conducted to simulate the control process and optimize the parameters. Preliminary results demonstrate that the BWS system can provide the desired support force and vertical motion of the pelvis.

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Vertical Structure of Spiral Shocks in a Corrugated Galactic Disc

Symposium - International Astronomical Union ◽

10.1017/s007418090003268x ◽

1983 ◽

Vol 100 ◽

pp. 145-146

Author(s):

A. H. Nelson ◽

T. Matsuda ◽

T. Johns

Keyword(s):

Density Profile ◽

Vertical Velocity ◽

Gas Flow ◽

Vertical Structure ◽

Vertical Motion ◽

Shock Structure ◽

Galactic Disc ◽

Gaussian Density ◽

Abundant Evidence ◽

Steady Shock

Numerical calculations of spiral shocks in the gas discs of galaxies (1,2,3) usually assume that the disc is flat, i.e. the gas motion is purely horizontal. However there is abundant evidence that the discs of galaxies are warped and corrugated (4,5,6) and it is therefore of interest to consider the effect of the consequent vertical motion on the structure of spiral shocks. If one uses the tightly wound spiral approximation to calculate the gas flow in a vertical cut around a circular orbit (i.e the ⊝ -z plane, see Nelson & Matsuda (7) for details), then for a gas disc with Gaussian density profile in the z-direction and initially zero vertical velocity a doubly periodic spiral potential modulation produces the steady shock structure shown in Fig. 1. The shock structure is independent of z, and only a very small vertical motion appears with anti-symmetry about the mid-plane.

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Constraints on the vertical motion of eastern Australia during the Mesozoic

Basin Research ◽

10.1111/j.1365-2117.1994.tb00077.x ◽

1994 ◽

Vol 6 (2-3) ◽

pp. 77-94 ◽

Cited By ~ 42

Author(s):

KERRY Gallagher ◽

TREVOR A. Dumitru ◽

ANDREW J. W. Gleadow

Keyword(s):

Vertical Motion ◽

Eastern Australia

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Isolation Performance of Intelligent Seismic Isolation System Using Air Bearing

Volume 8: Seismic Engineering ◽

10.1115/pvp2009-77600 ◽

2009 ◽

Cited By ~ 1

Author(s):

Satoshi Fujita ◽

Keisuke Minagawa ◽

Mitsuru Miyazaki ◽

Go Tanaka ◽

Toshio Omi ◽

...

Keyword(s):

Seismic Isolation ◽

Seismic Waves ◽

Three Dimensional ◽

Vertical Motion ◽

Air Bearings ◽

Natural Period ◽

Isolation System ◽

Vertical Excitation ◽

Long Period ◽

Isolation Performance

This paper describes three-dimensional isolation performance of seismic isolation system using air bearings. Long period seismic waves having predominant period of from a few seconds to a few ten seconds have recently been observed in various earthquakes. Also resonances of high-rise buildings and sloshing of petroleum tanks in consequence of long period seismic waves have been reported. Therefore the isolation systems having very long natural period or no natural period are required. In a previous paper [1], we proposed an isolation system having no natural period by using air bearings. Additionally we have already reported an introduction of the system, and have investigated horizontal motion during earthquake in the previous paper. It was confirmed by horizontal vibration experiment and simulation in the previous paper that the proposed system had good performance of isolation. However vertical motion should be investigated, because vertical motion varies horizontal frictional force. Therefore this paper describes investigation regarding vertical motion of the proposed system by experiment. At first, a vertical excitation test of the system is carried out so as to investigate vertical dynamic property. Then a three-dimensional vibration test using seismic waves is carried out so as to investigate performance of isolation against three-dimensional seismic waves.

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Influence of the Upstream Terrain on the Formation of a Cold Frontal Snowband in Northeast China

Asia-Pacific Journal of Atmospheric Sciences ◽

10.1007/s13143-021-00243-4 ◽

2021 ◽

Author(s):

Na Li ◽

Baofeng Jiao ◽

Lingkun Ran ◽

Zongting Gao ◽

Shouting Gao

Keyword(s):

Gravity Waves ◽

Northeast China ◽

Large Scale ◽

Control Experiment ◽

Vertical Motion ◽

Near Surface ◽

Inertial Instability ◽

Two Factors ◽

Negative Effect ◽

Conditional Instability

AbstractWe investigated the influence of upstream terrain on the formation of a cold frontal snowband in Northeast China. We conducted numerical sensitivity experiments that gradually removed the upstream terrain and compared the results with a control experiment. Our results indicate a clear negative effect of upstream terrain on the formation of snowbands, especially over large-scale terrain. By thoroughly examining the ingredients necessary for snowfall (instability, lifting and moisture), we found that the release of mid-level conditional instability, followed by the release of low-level or near surface instabilities (inertial instability, conditional instability or conditional symmetrical instability), contributed to formation of the snowband in both experiments. The lifting required for the release of these instabilities was mainly a result of frontogenetic forcing and upper gravity waves. However, the snowband in the control experiment developed later and was weaker than that in the experiment without upstream terrain. Two factors contributed to this negative topographic effect: (1) the mountain gravity waves over the upstream terrain, which perturbed the frontogenetic circulation by rapidly changing the vertical motion and therefore did not favor the release of instabilities in the absence of persistent ascending motion; and (2) the decrease in the supply of moisture as a result of blocking of the upstream terrain, which changed both the moisture and instability structures leeward of the mountains. A conceptual model is presented that shows the effects of the instabilities and lifting on the development of cold frontal snowbands in downstream mountains.

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Design, static analysis and development of a new three-legged shake table

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211018487 ◽

2021 ◽

pp. 095440622110184

Author(s):

Ganesh Mangavu ◽

Anjan Kumar Dash

Keyword(s):

Vertical Motion ◽

Torsional Stiffness ◽

Shake Table ◽

Lateral Motion ◽

Sinusoidal Motion ◽

Gravity Load ◽

Simulation Results ◽

Electromechanical Actuation ◽

Translational Stiffness ◽

Earthquake Data

In this paper, an alternative design is proposed based on a family of three-legged manipulators. Such manipulators have two actuators (one vertical and one horizontal) in each leg, unlike the standard UP̅S Stewart platform, which has one actuator in each leg. The arrangement of the two actuators is such a way that, to have vertical motion of the shake table only the Vertical Motion Actuators (VMA) are actuated and for longitudinal or lateral motion, the Horizontal Motion Actuators (HMA) alone are moved. Due to its inherent features such as simplified kinematics, control and distributed loading, a study is carried out to determine the performance of such three-legged manipulators as a shake table. Sinusoidal motion and white noise motions are given to the actuators and shown that the VMA forces have linear relationship with the platform forces. The translational stiffness and the torsional stiffness are studied separately for the manipulators. In the dynamic analysis, it is highlighted that the gravity load of the legs is borne by the Vertical actuators, irrespective of the motion being spatial or planar. Hence, this topology provides scope for lighter electromechanical actuation. The performance analysis of the 3 legged configuration is accomplished using simulation results, in comparison to a 7-UP̅S configuration of shake table. A prototype of the shake table is fabricated and tested with earthquake data of El Centro.

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