Total angle about the vertex of a cone in Galilean space

1988 ◽  
Vol 43 (5) ◽  
pp. 379-382
Author(s):  
A. Artykbaev
Keyword(s):  
Galilean Space ◽  
Total Angle

GENERALIZED HANNAY ANGLE FOR THE MOST GENERAL TIME-DEPENDENT HARMONIC OSCILLATOR

1993 ◽  
Vol 07 (28) ◽  
pp. 4827-4840 ◽  
Author(s):  
DONALD H. KOBE ◽  
JIONGMING ZHU
Keyword(s):  
Harmonic Oscillator ◽  
Berry Phase ◽  
Time Dependent ◽  
Canonical Momentum ◽  
Gauge Invariant ◽  
Classical Counterpart ◽  
Mass Spring ◽  
Adiabatic Case ◽  
General Time ◽  
Total Angle

The most general time-dependent Hamiltonian for a harmonic oscillator is both linear and quadratic in the coordinate and the canonical momentum. It describes in general a harmonic oscillator with mass, spring “constant,” and friction (or antifriction) “constant,” all of which are time dependent, that is acted on by a time-dependent force. A generalized Hannay angle, which is gauge invariant, is defined by making a distinction between the Hamiltonian and the energy. The generalized Hannay angle is the classical counterpart of the generalized Berry phase in quantum theory. When friction is present the generalized Hannay angle is nonzero. If the Hamiltonian is (incorrectly) chosen to be the energy, the generalized Hannay angle is different. Nevertheless, in the adiabatic case the same total angle is obtained.

Quantitative studies of the reactions to horizontal angular accelerations in axolotls. I. The head-turning reflexes of normal animals

1977 ◽  
Vol 66 (1) ◽  
pp. 1-14
Author(s):  
K. Brandle
Keyword(s):  
Stimulus Intensity ◽  
Time Course ◽  
Maximum Velocity ◽  
Afferent Input ◽  
Head Turning ◽  
Mean Values ◽  
Quantitative Studies ◽  
The Mean ◽  
Negative Exponential ◽  
Total Angle

1. Artifically metamorphosed axolotls were exposed to both brief (impulse) and long-lasting horizontal angular accelerations on a turn-table. The animals responded with a head-turning reaction. 2. The general course of the reaction to impulse acceleration was independent of stimulus intensity. The velocity of the head movement first increased to a maximum exponentially and then decreased in a negative exponential manner. Stimulus intensity had a linear relationship to the mean maximum velocity and mean total angle covered by head-turning. The average velocity-time curves at various stimulus intensities differed only by a velocity factor. 3. During long-lasting constant accelerations the velocity of the head-turning increased to a maximum velocity in a sigmoid time-course and then decreased, first to a constant velocity, and then further. Mean values of the maximum velocity were correlated linearly with the stimulus intensity. 4. It was concluded that the head-turning reflexes in axolotls do not agree with the accepted movements of the vertebrate cupula and therefore are not a simple ‘copy’ of the afferent input. It is also suggested that the reaction threshold differes from that for the labyrinthine input.

Assistive Force Redirection of Crutch Gait Produced by the Kinetic Crutch Tip

2017 ◽  
Author(s):  
Fatemeh Rasouli ◽  
Alex Torres ◽  
Kyle B. Reed
Keyword(s):  
Carbon Fiber ◽  
Healthy Subjects ◽  
Human Factor ◽  
Free Fall ◽  
Horizontal Force ◽  
Fiber Reinforced ◽  
3D Printed ◽  
Carbon Fiber Reinforced ◽  
Total Angle

This paper investigates how crutch tip designs affect the user’s gait. Five Kinetic Crutch Tips (KCT), each with different durometers (i.e., stiffnesses) along with one carbon fiber reinforced nylon 3D printed KCT and one Standard Rubber Tip were tested. The first experiment examined eight healthy subjects to determine the assistive horizontal force generated and crutch angle range. The second experiment eliminates the human factor and uses a weighted crutch in free fall to investigate transitional angles between forward and backward motions. It was found that the KCT had a larger transitional angle than the Standard Rubber Tip. This increases the assistive forward forces of the crutch due to the surface kinetic shape of KCTs; however, the total angle of different crutch tips remains the same when used by the subjects. The assistive forces were present for the longest amount of time for the highest durometer KCT.

scholarly journals Scalable Bi-Directional SMA-Based Rotational Actuator

Actuators ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 60 ◽  
Author(s):  
Rouven Britz ◽  
Paul Motzki ◽  
Stefan Seelecke
Keyword(s):  
Modular Design ◽  
High Weight ◽  
State Of The Art ◽  
Industrial Applications ◽  
Combustion Engines ◽  
Rotational Angle ◽  
Output Torque ◽  
Rotational Actuator ◽  
Rotatory Motion ◽  
Total Angle

In industrial applications, rotatory motions and torques are often needed. State-of-the-art actuators are based on either combustion engines, electro-motors, hydraulic, or pneumatic machines. The main disadvantages are the construction space, the high weight, and a large amount of needed peripheral devices. To overcome these limitations, compact and light-weight actuator systems can be built by using shape memory alloys (SMAs), which are known for their superior energy density. In this paper, the development of a scalable bi-directional rotational actuator based on SMA wires is presented. The scalability was based on a modular design, which allowed the actuator to be adapted to various application specifications by customizing the rotational angle and the output torque. On the mechanical side, each module enabled a small rotatory motion, which added up to the total angle of the actuator. The SMA wires were arranged in an agonist-antagonist configuration to provide active rotation in both directions. The presented prototype achieved a total rotation of 100°. The modularity of the mechanical concept is also reflected in the electronics, which is discussed in this paper as well. This consideration allows the electronics to be adapted to the mechanics with minimal changes. As a result, a prototype, including the presented mechanical and electronic design, is reported in this study.

GALILEAN AND DISCRETE SPACE-TIME SYMMETRIES OF ROY-SINGH DETERMINISTIC QUANTUM MECHANICS

1995 ◽  
Vol 10 (32) ◽  
pp. 4641-4650
Author(s):  
ARVIND KUMAR
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Time Reversal ◽  
Space Time ◽  
Discrete Space ◽  
Galilean Space

The recent deterministic quantum theory of Roy and Singh is shown to be covariant with respect to Galilean, space reflection and time reversal transformations.

An Experimental Investigation of the Transitory Stall Regime in Two-Dimensional Diffusers

1974 ◽  
Vol 96 (1) ◽  
pp. 11-15 ◽  
Author(s):  
C. R. Smith ◽  
S. J. Kline
Keyword(s):  
Experimental Investigation ◽  
Flow Behavior ◽  
Flow Patterns ◽  
Two Dimensional ◽  
Stall Inception ◽  
The Mean ◽  
Mach Numbers ◽  
Total Angle

A study of flow behavior of transitory stall in two-dimensional diffusers at low Mach numbers is reported. The changes in flow patterns from stall inception to full-stall are described; the geometries for maximum fluctuations are located. The mean times and distribution of stall build-up and wash-out periods are given for a series of units of varying total angle. The mean times are found to scale on total stall volume, and a nondimensional correlation of stall period is given. The distribution of stall periods, for random inlet fluctuations, is found to be broad and strongly skewed toward lower periods. Comparable results are found in water for R∼104 and in air at R∼105. A further series of tests with periodic inlet disturbances indicates that the stall behavior is modified strongly when the pulsing period is 0.5 to 1.0 times the natuarl mean period, but not otherwise. Details of flow patterns and blockage are summarized.

Stokes Flow in a Driven Sector by Two Different Methods

1980 ◽  
Vol 47 (3) ◽  
pp. 482-484 ◽  
Author(s):  
J. Sanders ◽  
V. O’Brien ◽  
D. D. Joseph
Keyword(s):  
Finite Difference ◽  
Series Expansion ◽  
Stokes Flow ◽  
Finite Difference Approximation ◽  
Difference Approximation ◽  
Mutual Support ◽  
Biorthogonal Series ◽  
Total Angle

A biorthogonal series expansion and a numerical finite-difference approximation are applied to the problem of steady Stokes flow in a driven sector of 10° total angle, providing mutual support of the theoretical techniques. For this problem the method of biorthogonal series is faster, cheaper, and more accurate.

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