Determination of Arbitrary Tooth Displacements

1978 ◽  
Vol 57 (5-6) ◽  
pp. 663-674 ◽  
Author(s):  
R.J. Pryputniewicz ◽  
C.J. Burstone ◽  
W.W. Bowley
Keyword(s):  
Dimensional Space ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Double Exposure ◽  
Maxillary Central Incisor ◽  
Modern Technique ◽  
Hologram Interferometry ◽  
Component Loading ◽  
Three Dimensional Space

The noninvasive, modern technique based on the method of double-exposure hologram interferometry was used to measure arbitrary displacements of teeth in the three dimensional space. The experimental studies were carried out on an idealized model of the maxillary central incisor. The results show that the experimental data, based on component loading, are inadequate to accurately predict tooth displacement from an arbitrary force acting in the three dimensional space.

Moire´-Holographic Technique for Three-Dimensional Stress Analysis

1970 ◽  
Vol 37 (1) ◽  
pp. 180-185 ◽  
Author(s):  
C. A. Sciammarella ◽  
G. Di Chirico ◽  
T.-Y. Chang
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Reconstruction Process ◽  
Double Beam ◽  
Out Of Plane ◽  
Hologram Interferometry ◽  
Moire Method ◽  
Diffraction Patterns ◽  
Good Agreement ◽  
Three Dimensional Space

The moire´ method is combined with hologram interferometry to obtain the three displacements of an arbitrarily deformed plane in the three-dimensional space. Double beam interference patterns are utilized. The interfering beams are obtained from the diffraction patterns of a grating printed in the analyzed plane. The in-plane and the out-of-plane displacements are measured in separate steps and yield separate patterns. The patterns are generated by double exposure and observed by a wave front reconstruction process. The experimental results included in the paper show a good agreement with theoretical results, proving the feasibility of the proposed technique.

Determination of the modulated structure of Sr14/11CoO3 through a (3 + 1)-dimensional space description and using non-harmonic ADPs

1999 ◽  
Vol 55 (6) ◽  
pp. 841-848 ◽  
Author(s):  
O. Gourdon ◽  
V. Petricek ◽  
M. Dusek ◽  
P. Bezdicka ◽  
S.  Durovic ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Atomic Displacement ◽  
Atomic Displacement Parameter ◽  
Third Order ◽  
Modulated Structure ◽  
New Phase ◽  
Space Description ◽  
Three Dimensional Space

Sr14/11CoO3 (i.e. Sr14Co11O33, tetradecastrontium undecacobalt tritriacontaoxide), a new phase in the hexagonal perovskite Sr x CoO3 system, has been prepared and its structure solved from single-crystal X-ray data within the (3 + 1)-dimensional formalism. Sr14/11CoO3 crystallizes in the trigonal symmetry, R3¯m(00γ)0s superspace group with the following lattice parameters: as = 9.508 (2), cs = 2.5343 (7) Å, q = 0.63646 (11)c * and Vs = 198.40 (13) Å3. With the commensurate versus incommensurate test not being conclusive, the structure was considered as commensurate (P32 three-dimensional space group), but refined within the (3 + 1)-dimensional formalism to a residual factor R = 0.0351 for 47 parameters and 1169 independent reflections. Crenel functions were used for the oxygen and cobalt description and a Gram–Charlier expansion up to the third order of the atomic displacement parameter was employed for one Co atom. The structure is similar to that of Sr6/5CoO3, but with a different sequence of the octahedra and trigonal prism polyhedra along the [CoO3] chains. An interesting feature evidenced by the non-harmonic expansion is the displacement of the prismatic Co atoms from the site center, towards the prism rectangular faces.

scholarly journals Vector Products As A Tool For The Investigation Of The Isometric Transformation Of Objects

2015 ◽  
Vol 98 (1) ◽  
pp. 60-71
Author(s):  
Ryszard Józef Grabowski
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Necessary Condition ◽  
Vector Product ◽  
Isometric Transformation ◽  
Check Points ◽  
Normal Vectors ◽  
Definition Of ◽  
Three Dimensional Space

Abstract The identification of isometric displacements of studied objects with utilization of the vector product is the aim of the analysis conducted in this paper. Isometric transformations involve translation and rotation. The behaviour of distances between check points on the object in the first and second measurements is a necessary condition for the determination of such displacements. For every three check points about the measured coordinate, one can determine the vector orthogonal to the two neighbouring sides of the triangle that are treated as vectors, using the definition of the vector product in three-dimensional space. If vectors for these points in the first and second measurements are parallel to the studied object has not changed its position or experienced translation. If the termini of vectors formed from vector products treated as the vectors are orthogonal to certain axis, then the object has experienced rotation. The determination of planes symmetric to these vectors allows the axis of rotation of the object and the angle of rotation to be found. The changes of the value of the angle between the normal vectors obtained from the first and second measurements, by exclusion of the isometric transformation, are connected to the size of the changes of the coordinates of check points, that is, deformation of the object. This paper focuses mainly on the description of the procedure for determining the translation and rotation. The main attention was paid to the rotation, due to the new and unusual way in which it is determined. Mean errors of the determined parameters are often treated briefly, and this subject requires separate consideration.

Determination of Translation Component of Screw Axis From Double-Exposure Holographic Interferograms

1996 ◽  
Author(s):  
L. A. Sanchez ◽  
A. D. Zurek ◽  
J. A. Griffis
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Rigid Bodies ◽  
Optical Methods ◽  
Screw Axis ◽  
Double Exposure ◽  
Translation Component ◽  
Fringe Patterns ◽  
Relative Motions

Abstract In mechanism design, it is often necessary to accurately measure the relative motions produced by an assembly of rigid bodies connected by joints. A number of analytical tools exist for the theoretical kinematic analysis of the relative motions produced by such an assembly. However, a relatively limited number of corresponding experimental methods for handling such motions exist. Optical methods are especially useful because they do not require that the measurement system touch the assembly being analyzed. A photo-optical method, holographic interferometry, is presented for the experimental determination of finite screw displacements. The purpose of this paper is to show how double-exposure holographic interferograms can be used to provide information about screw axes for general motions of an object in three-dimensional space. This investigation deals with the translation component of a screw axis and categorizes the fringe patterns resulting from in-plane and out-of-plane translations and their combinations. The resulting screw axis for each special displacement case is computed.

Determination of Sound Velocity in Three-Dimensional Space by Optical Probe

2008 ◽  
Vol 47 (5) ◽  
pp. 3959-3961 ◽  
Author(s):  
Takeshi Ohbuchi ◽  
Koichi Mizutani ◽  
Naoto Wakatsuki ◽  
Hiroyuki Masuyama
Keyword(s):  
Sound Velocity ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Optical Probe ◽  
Three Dimensional Space

A 3D stable trot of a quadruped robot over uneven terrains

2016 ◽  
Vol 231 (3) ◽  
pp. 555-573 ◽  
Author(s):  
Mahdi Khorram ◽  
S Ali A Moosavian
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Quadruped Robot ◽  
Legged Robots ◽  
Whole Body ◽  
Main Body ◽  
Stable Gait ◽  
Three Dimensional Space

Legged robots have superior advantages rather than wheeled robots for moving over uneven terrains in the presence of various obstacles. The design of an appropriate path for the main body and legs is an important issue for such robots especially on the uneven terrains. In this paper, the focus is to develop a stable gait for a quadruped robot to trot on uneven terrains. First, a stability condition is developed for a whole-body quadruped robot over uneven terrains based on avoiding the tumbling. By using a simple model, a point with zero moments is calculated in the three-dimensional space. Then, the reference path of this point is determined so that the tumbling moments become zero. The path of the main body will be calculated by using an optimal controller. The main feature of the proposed gait generation framework is that the height of robot can change continuously and stably on uneven terrains. To evaluate the robot stability, the tumbling moments around diagonal lines are calculated and some methods are proposed to reduce these moments to improve the robot stability. The tip of swing foot is also planned to avoid any collision with the environment. The proposed method will be demonstrated using an 18-Degrees of freedom (DOF) quadruped robot in simulation and experimental studies. The experimental setup is a small-size quadruped robot, which is composed of a rectangular plate as its main body with four legs that each one has three active joints with DC servo motors. Obtained results reveal that the robot can trot on uneven terrains stably. Besides, the comparison with the previous methods approves the merits of proposed algorithm on uneven terrains.

MAP FORMATION IN PROPRIOCEPTIVE CORTEX

1994 ◽  
Vol 05 (02) ◽  
pp. 87-101 ◽  
Author(s):  
SUNGZOON CHO ◽  
JAMES A. REGGIA
Keyword(s):  
Primary Motor Cortex ◽  
Dimensional Space ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Muscle Length ◽  
Muscle Group ◽  
Feature Maps ◽  
Organizational Issues ◽  
Muscle Groups ◽  
Three Dimensional Space

Current understanding of feature maps in proprioceptive cortex is quite limited. To complement experimental studies, we developed a computational model of map formation in proprioceptive cortex. Muscle length and tension from six muscle groups controlling the position of a model arm in three-dimensional space served as input to the simulated cortex. The resultant feature map consisted of regularly spaced clusters of cortical columns representing individual muscle lengths and tensions. Cortical units became tuned to plausible combinations of tension and length, and multiple representations of each muscle group were present. The map was organized such that compact regions within which all muscle group lengths and tensions are represented could be identified. Most striking was the observation that, although not explicitly present in the input, the cortical map developed a representation of the three-dimensional space in which the arm moved. These findings represent testable predictions about proprioceptive cortex, and may also help clarify some organizational issues concerning primary motor cortex.

In Vivo Determination of the Direction of Rotation and Moment-Angle Relationship of Individual Elbow Muscles

1998 ◽  
Vol 120 (5) ◽  
pp. 625-633 ◽  
Author(s):  
L. Zhang ◽  
J. Butler ◽  
T. Nishida ◽  
G. Nuber ◽  
H. Huang ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Elbow Flexion ◽  
Joint Movement ◽  
Flexion Extension ◽  
Relationship Of ◽  
Three Dimensional Space

The direction of rotation (DOR) of individual elbow muscles, defined as the direction in which a muscle rotates the forearm relative to the upper arm in three-dimensional space, was studied in vivo as a function of elbow flexion and forearm rotation. Electrical stimulation was used to activate an individual muscle selectively, and the resultant flexion-extension, supination-pronation, and varus-valgus moments were used to determine the DOR. Furthermore, multi-axis moment-angle relationships of individual muscles were determined by stimulating the muscle at a constant submaximal level across different joint positions, which was assumed to result in a constant level of muscle activation. The muscles generate significant moments about axes other than flexion-extension, which is potentially important for actively controlling joint movement and maintaining stability about all axes. Both the muscle DOR and the multi axis moments vary with the joint position systematically. Variations of the DOR and moment-angle relationship across muscle twitches of different amplitudes in a subject were small, while there were considerable variations between subjects.

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