The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Itaru Mizoguchi - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of the finite helical axis and the Rectangular Coordinate System in representing orthodontic tooth movement
    Journal of biomechanics, 2005
    Co-Authors: Kazuo Hayashi, Ralph Delong, Itaru Mizoguchi
    Abstract:

    In orthodontics, tooth movement is typically described using the Rectangular Coordinate System (XYZ); however, this System has several disadvantages when performing biomechanical analyses. An alternative method is the finite helical axis (FHA) System, which describes movement as a rotation about and a translation along a single axis located in space. The purpose of this study was to examine differences between the FHA and the XYZ Systems in analyzing orthodontic tooth movement. Maxillary canine retraction was done using sliding mechanics or a retraction spring with midpalatal orthodontic implants used as measuring references. Tooth movement calculated with the FHA was compared with the corresponding movement in the Rectangular Coordinate System weekly over a 2-month interval in eight patients. The FHA showed that sliding mechanics controlled rotation of the canine better than the retraction spring (Ricketts retractor), and that the Ricketts retractor controlled tipping better. Changes in the FHA direction and position vectors with time showed that the biomechanical forces are not uniform during the treatment period. In both mechanics, the FHA provided a simple biomechanical model for canine retraction.

  • Basic behavior of the finite helical axis in a simple tooth movement simulation.
    Medical engineering & physics, 2004
    Co-Authors: Kazuo Hayashi, Humiki Tanaka, Kazuhiro Hikita, Itaru Mizoguchi
    Abstract:

    A finite helical axis (FHA) analysis can provide precise three-dimensional information on orthodontic tooth movement compared to an analysis based on a Rectangular Coordinate System. The FHA has already been applied in an analysis of orthodontic tooth movement. Interestingly, the position of the FHA changes dramatically in different stages of treatment; however, no previous report has provided detailed information of its basic behavior for clinicians. The purpose of this study was to clarify the basic behavior of the FHA in simple tooth movement, which could promote a better understanding of the 3-D orientation of and rotation about the FHA during tooth movement. Parameters of the FHA were calculated from a simulation of canine retraction. As the tipping angle of the canine was increased from 5 degrees to 30 degrees , the orientation vector of the FHA approached the most affected axis of rotation (on a Rectangular Coordinate System) in a non-linear manner. The angle of rotation about the FHA also increased in a non-linear manner. This non-linear problem was solved analytically. The basic behavior of the orientation vector of the FHA and the non-linear characteristics of the FHA parameters clarified in this study should be important for the future analysis of actual tooth movement based on the FHA. However, we must be aware that the non-linearity of the FHA itself may affect the analysis of the mechanical properties of the periodontal tissue.

Kazuo Hayashi - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of the finite helical axis and the Rectangular Coordinate System in representing orthodontic tooth movement
    Journal of biomechanics, 2005
    Co-Authors: Kazuo Hayashi, Ralph Delong, Itaru Mizoguchi
    Abstract:

    In orthodontics, tooth movement is typically described using the Rectangular Coordinate System (XYZ); however, this System has several disadvantages when performing biomechanical analyses. An alternative method is the finite helical axis (FHA) System, which describes movement as a rotation about and a translation along a single axis located in space. The purpose of this study was to examine differences between the FHA and the XYZ Systems in analyzing orthodontic tooth movement. Maxillary canine retraction was done using sliding mechanics or a retraction spring with midpalatal orthodontic implants used as measuring references. Tooth movement calculated with the FHA was compared with the corresponding movement in the Rectangular Coordinate System weekly over a 2-month interval in eight patients. The FHA showed that sliding mechanics controlled rotation of the canine better than the retraction spring (Ricketts retractor), and that the Ricketts retractor controlled tipping better. Changes in the FHA direction and position vectors with time showed that the biomechanical forces are not uniform during the treatment period. In both mechanics, the FHA provided a simple biomechanical model for canine retraction.

  • Basic behavior of the finite helical axis in a simple tooth movement simulation.
    Medical engineering & physics, 2004
    Co-Authors: Kazuo Hayashi, Humiki Tanaka, Kazuhiro Hikita, Itaru Mizoguchi
    Abstract:

    A finite helical axis (FHA) analysis can provide precise three-dimensional information on orthodontic tooth movement compared to an analysis based on a Rectangular Coordinate System. The FHA has already been applied in an analysis of orthodontic tooth movement. Interestingly, the position of the FHA changes dramatically in different stages of treatment; however, no previous report has provided detailed information of its basic behavior for clinicians. The purpose of this study was to clarify the basic behavior of the FHA in simple tooth movement, which could promote a better understanding of the 3-D orientation of and rotation about the FHA during tooth movement. Parameters of the FHA were calculated from a simulation of canine retraction. As the tipping angle of the canine was increased from 5 degrees to 30 degrees , the orientation vector of the FHA approached the most affected axis of rotation (on a Rectangular Coordinate System) in a non-linear manner. The angle of rotation about the FHA also increased in a non-linear manner. This non-linear problem was solved analytically. The basic behavior of the orientation vector of the FHA and the non-linear characteristics of the FHA parameters clarified in this study should be important for the future analysis of actual tooth movement based on the FHA. However, we must be aware that the non-linearity of the FHA itself may affect the analysis of the mechanical properties of the periodontal tissue.

Xian Yong - One of the best experts on this subject based on the ideXlab platform.

  • Three-dimensional Simulation of Flight Trajectory of Ballistic Missile
    Computer Simulation, 2005
    Co-Authors: Xian Yong
    Abstract:

    External modeling tool is used to construct geometric model of the earth and ballistic missile, and corresponding texture map Coordinates are generated in this paper. Moreover, graph interface module of OpenGL is also used to realize three-dimensional simulation of the earth moving object, and the space Rectangular Coordinate System of the earth is established according to the texture Coordinates. On this basis, by means of the transform relation between the constructed launch Coordinate System, the geocentric Rectangular Coordinate System and the model Coordinate System, the three-dimensional display of the flight trajectory, firepower circle, defense area of ballistic missile are realized. With visual, real-time and interactive property as its main advantages, this method breaks the limitation of the traditional two-dimensional display method by which the trajectory of missile or satellite is displayed in the form of projection on map plane.

Irving Israel Ruiz-lópez - One of the best experts on this subject based on the ideXlab platform.

  • Analytical solution of simultaneous heat and mass transfer equations during food drying
    Journal of Food Engineering, 2014
    Co-Authors: Miguel Ángel García-alvarado, F.m. Pacheco-aguirre, Irving Israel Ruiz-lópez
    Abstract:

    Abstract A rigorous dimensionless analysis of simultaneous heat and mass transfer equations for food drying was developed and simplified for constant properties. From the simplified result, an analytical solution in 1D Rectangular Coordinate System was obtained. As opposed to Luikov’s Equations (LE), the reported solution considers the effect of temperature on interface moisture content. The analytical solution was obtained by Laplace transform and complex inversion integral with space dependent function as initial conditions. The solution behavior compared with some experimental data was detailed, and the potential of the reported solution for the study of interface phenomena and variable mass transfer properties was discussed.

Ralph Delong - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of the finite helical axis and the Rectangular Coordinate System in representing orthodontic tooth movement
    Journal of biomechanics, 2005
    Co-Authors: Kazuo Hayashi, Ralph Delong, Itaru Mizoguchi
    Abstract:

    In orthodontics, tooth movement is typically described using the Rectangular Coordinate System (XYZ); however, this System has several disadvantages when performing biomechanical analyses. An alternative method is the finite helical axis (FHA) System, which describes movement as a rotation about and a translation along a single axis located in space. The purpose of this study was to examine differences between the FHA and the XYZ Systems in analyzing orthodontic tooth movement. Maxillary canine retraction was done using sliding mechanics or a retraction spring with midpalatal orthodontic implants used as measuring references. Tooth movement calculated with the FHA was compared with the corresponding movement in the Rectangular Coordinate System weekly over a 2-month interval in eight patients. The FHA showed that sliding mechanics controlled rotation of the canine better than the retraction spring (Ricketts retractor), and that the Ricketts retractor controlled tipping better. Changes in the FHA direction and position vectors with time showed that the biomechanical forces are not uniform during the treatment period. In both mechanics, the FHA provided a simple biomechanical model for canine retraction.