scholarly journals Unifying static and dynamic properties in three-dimensional quantum antiferromagnets

2017 ◽  
Vol 96 (17) ◽  
Author(s):  
H. D. Scammell ◽  
Y. Kharkov ◽  
Yan Qi Qin ◽  
Zi Yang Meng ◽  
B. Normand ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Three Dimensional ◽  
Quantum Antiferromagnets

scholarly journals Fast Overlap Detection between Hard-Core Colloidal Cuboids and Spheres. The OCSI Algorithm

Algorithms ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 72
Author(s):  
Luca Tonti ◽  
Alessandro Patti
Keyword(s):  
Colloidal Particles ◽  
Dynamic Properties ◽  
Wide Spectrum ◽  
Three Dimensional ◽  
Hard Core ◽  
Detection Algorithm ◽  
Three Dimensional Objects ◽  
Aggregation Behaviour ◽  
Sphere Radius ◽  
User Friendly

Collision between rigid three-dimensional objects is a very common modelling problem in a wide spectrum of scientific disciplines, including Computer Science and Physics. It spans from realistic animation of polyhedral shapes for computer vision to the description of thermodynamic and dynamic properties in simple and complex fluids. For instance, colloidal particles of especially exotic shapes are commonly modelled as hard-core objects, whose collision test is key to correctly determine their phase and aggregation behaviour. In this work, we propose the Oriented Cuboid Sphere Intersection (OCSI) algorithm to detect collisions between prolate or oblate cuboids and spheres. We investigate OCSI’s performance by bench-marking it against a number of algorithms commonly employed in computer graphics and colloidal science: Quick Rejection First (QRI), Quick Rejection Intertwined (QRF) and a vectorized version of the OBB-sphere collision detection algorithm that explicitly uses SIMD Streaming Extension (SSE) intrinsics, here referred to as SSE-intr. We observed that QRI and QRF significantly depend on the specific cuboid anisotropy and sphere radius, while SSE-intr and OCSI maintain their speed independently of the objects’ geometry. While OCSI and SSE-intr, both based on SIMD parallelization, show excellent and very similar performance, the former provides a more accessible coding and user-friendly implementation as it exploits OpenMP directives for automatic vectorization.

scholarly journals Design, Fabrication, and Testing of a Novel 3D 3-Fingered Electrothermal Microgripper with Multiple Degrees of Freedom

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 444
Author(s):  
Guoning Si ◽  
Liangying Sun ◽  
Zhuo Zhang ◽  
Xuping Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Polyimide Film ◽  
Zebrafish Embryos ◽  
Multiple Degrees Of Freedom ◽  
Electrothermal Actuator ◽  
3D Space ◽  
Pick And Place

This paper presents the design, fabrication, and testing of a novel three-dimensional (3D) three-fingered electrothermal microgripper with multiple degrees of freedom (multi DOFs). Each finger of the microgripper is composed of a V-shaped electrothermal actuator providing one DOF, and a 3D U-shaped electrothermal actuator offering two DOFs in the plane perpendicular to the movement of the V-shaped actuator. As a result, each finger possesses 3D mobilities with three DOFs. Each beam of the actuators is heated externally with the polyimide film. The durability of the polyimide film is tested under different voltages. The static and dynamic properties of the finger are also tested. Experiments show that not only can the microgripper pick and place microobjects, such as micro balls and even highly deformable zebrafish embryos, but can also rotate them in 3D space.

An Investigation of the Structural Dynamics of a Racing Yacht

1999 ◽  
Author(s):  
Frederic Louarn ◽  
Pandeli Temarel
Keyword(s):  
Dynamic Properties ◽  
Three Dimensional ◽  
Element Model ◽  
Point Of View ◽  
Mode Shapes ◽  
Function Technique ◽  
Operational Conditions ◽  
Principal Coordinates ◽  
Modal Summation ◽  
Structural Responses

The dynamic behaviour of a WOR 60 is investigated using three dimensional hydroelasticity theory. Global structural responses (e.g. stresses) in waves are obtained corresponding to the upright as well as to the more realistic heeled sailing configurations, revealing the connection between the ballast keel and the hull as being a critical area of the structure. For the "dry hull" analysis, a global finite element model has been developed, incorporating the hull and deck shell, the internal structure, the ballast keel and the rig together with rigging loads. The modular nature of the model has been used to assess the relative influence of each of the aforementioned components upon the required characteristic dynamic properties (e.g. natural frequencies and principal mode shapes). Regarding the "wet hull" analysis, a three dimensional Green's function technique, using pulsating sources distributed over the wetted surface, provides a numerical solution to the case of the yacht sailing in regular waves at arbitrary heading. Principal coordinates for the rigid body motions and flexible distortions of interest are evaluated and the latter are used to obtain the dynamic stresses in waves using modal summation. This paper will describe the modelling techniques used and discuss the applicability / limitations of hydroelasticity theory regarding this type of structures in the light of the results obtained for the upright and heeled operational conditions, as well as from the point of view of design aspects such as "L" and "T" keel configurations. The ABS design criteria will provide a practical reference for comparing the results from the dynamic analysis.

Proprioceptive control of interjoint coordination

1995 ◽  
Vol 73 (2) ◽  
pp. 273-284 ◽  
Author(s):  
Claude Ghez ◽  
Robert Sainburg
Keyword(s):  
Internal Model ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Specific Response ◽  
Proprioceptive Information ◽  
Dynamic Interactions ◽  
Line Segments ◽  
Interjoint Coordination ◽  
Straight Line ◽  
Interaction Torques

This paper reviews a series of experiments comparing intact controls with functionally deafferented patients to determine the role of proprioception in controlling dynamic interactions between limb segments during movement. We examine the control of hand path in a planar movement-reversal task and in a familiar three-dimensional gesture with similar biomechanical characteristics. In the planar task subjects had to move their hand out and back along a series of straight-line segments in the horizontal plane without visual feedback. The lengths and directions of the target line segments were chosen to require different amounts of shoulder motion while requiring the same elbow excursion. In controls, hand paths were, as required, straight with sharp bends at the outermost point. In patients, however, distinctive errors appeared at movement reversals, consisting of widened hand paths resulting from desynchronization in the reversals of elbow and shoulder motions. These errors reflected an inability to program elbow muscle contractions in accord with interaction torques produced at the elbow by variations in acceleration of the shoulder. The reversal errors were substantially reduced after patients had practiced for a few trials while visually monitoring movements of their arm. The improvement was not limited to the direction where they had practiced with vision, but also extended to other directions in which the elbow torques were different. This suggests that practice with vision of the arm served to improve the general rules that subjects used to plan movement, rather than simply improving the performance of a specific response. Similar to their performance on the planar task, the patients made errors in interjoint coordination during unconstrained three-dimensional gestures with movement reversals. We conclude (i) that both the planning and the learning of movement required an internal model of the dynamic properties of the limb that takes account of interaction torques acting at different joints; (ii) that this internal model is normally established and updated using proprioceptive information; but (iii) that when proprioception is lacking, vision of the limb in motion partially substitutes for proprioception.Key words: proprioception, multijoint coordination, limb movement, multijoint dynamics, deafferentation.

VIBRATION OF CIRCULAR BLADED DISK WITH IMPERFECTIONS

2011 ◽  
Vol 21 (10) ◽  
pp. 2893-2904 ◽  
Author(s):  
LADISLAV PŮST ◽  
LUDĚK PEŠEK
Keyword(s):  
Dynamic Properties ◽  
Single Point ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Fe Model ◽  
Rotating Disks ◽  
Response Curves ◽  
State Response ◽  
Bladed Disk ◽  
Linear Damping

The steady state response of a model of circular bladed disk with imperfection is investigated. Disk imperfection results from additional two groups of damping heads fixed on opposite ends of one diameter. These damping heads are introduced into the computing model as additional point mass, damping and stiffness. Such type of imperfection causes the bifurcation of double eigenfrequencies into pairs of close eigenfrequencies. The effect of imperfection is examined both numerically on three-dimensional nonrotating FE-model and analytically on a simplified split 2DOF model of rotating disk excited by single point harmonic force. Nonlinear friction connection is analyzed and equivalent linear damping coefficient is derived and used in the calculation procedure. It is shown that nonproportional distribution of damping strongly influences the high of resonance peaks. Some examples of response curves illustrate the dynamic properties of stationary and rotating disks with mass-damping-stiffness imperfection.

Mesoscopic investigation of layered graded metallic foams under dynamic compaction

2018 ◽  
Vol 21 (14) ◽  
pp. 2081-2098 ◽  
Author(s):  
Jinhua Zhang ◽  
Yadong Zhang ◽  
Junyu Fan ◽  
Qin Fang ◽  
Yuan Long
Keyword(s):  
Impact Loading ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Metallic Foam ◽  
Layer By Layer ◽  
Metallic Foams ◽  
Mesoscopic Model ◽  
Layer Arrangement ◽  
Computed Tomography Images ◽  
Closed Cell

This article is aimed to reveal the dynamic response of layered graded metallic foam under impact loading using a three-dimensional mesoscopic model. First, a mesoscopic model for closed-cell metallic foam is proposed based on the X-ray computed tomography images. Second, a numerical analysis approach is presented and validated with test data. Third, it studies the dynamic behavior of the layered graded metallic foam under impact loading numerically. The metallic foam specimen is composed layer by layer. The porosity, which is a fraction of the voids volume over the total volume, is different with each other for the layers. Simulations are conducted to the specimen with increasing and decreasing porosity arrangement. Results show that the layer arrangement is critical to the dynamic properties. The mesoscopic deformation of cell walls and the energy absorption capability are also affected significantly. This article gives insights into the mechanical properties and mesoscopic deformation of layered graded metallic foam.

The three-dimensional solution structure and dynamic properties of the human FADD death domain 1 1Edited by A. Fersht

2000 ◽  
Vol 302 (1) ◽  
pp. 171-188 ◽  
Author(s):  
Helena Berglund ◽  
Dionne Olerenshaw ◽  
Andrew Sankar ◽  
Matthias Federwisch ◽  
Neil Q McDonald ◽  
...  
Keyword(s):  
Solution Structure ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Death Domain ◽  
Dimensional Solution

An Automated Three-Dimensional Particle Tracking Technique for the Study of Modeled Arterial Flow Fields

1995 ◽  
Vol 117 (2) ◽  
pp. 211-218 ◽  
Author(s):  
R. Tsao ◽  
S. A. Jones ◽  
D. P. Giddens ◽  
C. K. Zarins ◽  
S. Glagov
Keyword(s):  
Particle Tracking ◽  
Dynamic Properties ◽  
Video Recording ◽  
Three Dimensional ◽  
Flow Fields ◽  
Laser Doppler ◽  
Tracking Data ◽  
Tracking Technique ◽  
Doppler Data ◽  
Particle Paths

An automated three-dimensional particle tracking technique has been developed to study particle motion in modeled flow fields. A high speed video recording system, Kodak Ektapro 1000, with two cameras airanged relatively orthogonally is used for this technique. The particle tracking data are compared to theoretical Poiseuille flow and to laser Doppler data from an axisymmetric stenosis model. The particle tracking data are in good agreement with both theoretical and laser Doppler data, and at least 79 percent of the particle paths were determined successfully. Fluid dynamic properties derived by this technique are: 3-D particle paths, velocity, and particle residence time.

Dynamic Properties of Tilting-Pad Journal Bearings: Experimental and Theoretical Investigation of Frequency Effects due to Pivot Flexibility

2006 ◽  
Vol 129 (3) ◽  
pp. 865-869 ◽  
Author(s):  
Waldemar Dmochowski
Keyword(s):  
High Speed ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Damping Properties ◽  
Frequency Effects ◽  
Tilting Pad ◽  
Stiffness And Damping ◽  
Tilting Pad Journal Bearings

Tilting-pad journal bearings (TPJBs) dominate as rotor supports in high-speed rotating machinery. The paper analyzes frequency effects on the TPJB’s stiffness and damping characteristics based on experimental and theoretical investigations. The experimental investigation has been carried out on a five pad tilting-pad journal bearing of 98mm in diameter. Time domain and multifrequency excitation has been used to evaluate the dynamic coefficients. The calculated results have been obtained from a three-dimensional computer model of TPJB, which accounts for thermal effects, turbulent oil flow, and elastic effects, including that of pad flexibility. The analyzes of the TPJB’s stiffness and damping properties showed that the frequency effects on the bearing dynamic properties depend on the operating conditions and bearing design. It has been concluded that the pad inertia and pivot flexibility are behind the variations of the stiffness and damping properties with frequency of excitation.

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