scholarly journals Human Temporomandibular Joint Motion: A Synthesis Approach for Designing a Six-Bar Kinematic Simulator

2021 ◽  
pp. 1-12
Author(s):  
Michel Demuynck ◽  
Aidin Delnavaz ◽  
Jérémie Voix
Keyword(s):  
Temporomandibular Joint ◽  
Hearing Aids ◽  
Average Error ◽  
Joint Motion ◽  
Two Phase ◽  
Design Algorithm ◽  
Hearing Protectors ◽  
Hinge Axis ◽  
Synthesis Approach ◽  
Classical Optimization

Abstract The human earcanal can accommodate several types of in-ear devices including hearing aids, earphones, hearing protectors and earplugs. This canal-type home has a neighbor called the Temporomandibular Joint (TMJ) whose movements slightly deform the shape of the earcanal. While these cyclic deformations can influence the positioning, comfort and functioning of ear-fitted devices, they can also provide a significant amount of energy to harvest. Given their importance, the TMJ movements and earcanal deformations have been well studied. However, their mutual actions are still not fully understood. This paper presents the development of a six-bar kinematic TMJ simulator capable of replicating the complicated motion of the jaw. The development relies on a two-phase mechanism design algorithm to numerically optimize and analytically synthesize linkage mechanisms for which the classical optimization approaches cannot return a converged solution. The proposed algorithm enables the design of a kinematic simulator to generate the TMJ path with an average error as low as 1.65 % while respecting all the hinge-axis parameters of the jaw. This algorithm can be subsequently used to solve nonlinear complex linkage synthesis problems and ultimately, the developed kinematic simulator can be used to further investigate TMJ-earcanal interactions.

New Correlation for Two-Phase Flow in 90 Degree Horizontal Elbows

2010 ◽  
Author(s):  
Florencio Sanchez-Silva ◽  
Ignacio Carvajal-Mariscal ◽  
Rene Tolentino-Eslava
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Experimental Results ◽  
Galvanized Steel ◽  
Average Error ◽  
Phase Flow ◽  
Volumetric Fraction ◽  
Dean Number ◽  
Two Phase ◽  
Flow Pressure

The comparison of experimental data and results obtained from four global models — homogeneous, Dukler, Martinelli and Chisholm, used to evaluate the two-phase flow pressure drop in circular 90° horizontal elbows — is presented in this paper. An experimental investigation was carried out using three galvanized steel 90° horizontal elbows (E1, E2, E3) with internal diameters of 26.5, 41.2 and 52.5 mm, and curvature radii of 194.0, 264.0 and 326.6 mm, respectively. According to the experimental results, the model proposed by Chisholm best fitted them, presenting for each elbow an average error of E1 = 18.27%, E2 = 28.40% and E3 = 42.10%. Based on experimental results two correlations were developed. The first one is the classical Chisholm model modified to obtain better results in a wider range of conditions; it was adjusted by a dimensionless relationship which is a function of the homogeneous volumetric fraction and the Dean number. As a result, the predictions using modified Chisholm model were improved presenting an average error of 8.66%. The second developed correlation is based on the entire two-phase mass flow taken as liquid and adjusted by the homogeneous volumetric fraction ratio. The results show that this last correlation is easier and accurate than the adjusted Chisholm model, presenting an average error of 7.75%. Therefore, this correlation is recommended for two-phase pressure drop evaluation in horizontal elbows.

scholarly journals Optimizing the Geometry of Flexure System Topologies Using the Boundary Learning Optimization Tool

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Ali Hatamizadeh ◽  
Yuanping Song ◽  
Jonathan B. Hopkins
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Optimization Algorithm ◽  
Geometric Parameters ◽  
Average Error ◽  
Computational Tool ◽  
Model Training ◽  
Constraint Topologies ◽  
Synthesis Approach

We introduce a new computational tool called the Boundary Learning Optimization Tool (BLOT) that identifies the boundaries of the performance capabilities achieved by general flexure system topologies if their geometric parameters are allowed to vary from their smallest allowable feature sizes to their largest geometrically compatible feature sizes for given constituent materials. The boundaries generated by the BLOT fully define the design spaces of flexure systems and allow designers to visually identify which geometric versions of their synthesized topologies best achieve desired combinations of performance capabilities. The BLOT was created as a complementary tool to the freedom and constraint topologies (FACT) synthesis approach in that the BLOT is intended to optimize the geometry of the flexure topologies synthesized using the FACT approach. The BLOT trains artificial neural networks to create models of parameterized flexure topologies using numerically generated performance solutions from different design instantiations of those topologies. These models are then used by an optimization algorithm to plot the desired topology’s performance boundary. The model-training and boundary-plotting processes iterate using additional numerically generated solutions from each updated boundary generated until the final boundary is guaranteed to be accurate within any average error set by the user. A FACT-synthesized flexure topology is optimized using the BLOT as a simple case study.

scholarly journals Bioengineered Temporomandibular Joint Disk Implants: Study Protocol for a Two-Phase Exploratory Randomized Preclinical Pilot Trial in 18 Black Merino Sheep (TEMPOJIMS)

2017 ◽  
Vol 6 (3) ◽  
pp. e37 ◽  
Author(s):  
David Faustino Ângelo ◽  
Florencio Gil Monje ◽  
Raúl González-García ◽  
Christopher B Little ◽  
Lisete Mónico ◽  
...  
Keyword(s):  
Temporomandibular Joint ◽  
Study Protocol ◽  
Pilot Trial ◽  
Two Phase ◽  
Merino Sheep

Validation of a Simplified Transient Multiphase Flow Model for Any Pipe Inclination With Gulf of Mexico Field Data

2021 ◽  
Author(s):  
Ligia Tornisiello ◽  
Francisco Bruno Xavier Teles ◽  
Paulo J. Waltrich
Keyword(s):  
Field Data ◽  
Transient Flow ◽  
Two Phase Flow ◽  
Simplified Model ◽  
Average Error ◽  
Phase Flow ◽  
Two Phase ◽  
Validation Data ◽  
Data Set ◽  
Pipe Inclination

Abstract This paper presents a simplified model for transient two-phase flow in pipes of any inclinations, for slow transients. Such simplified model facilitates its use for real-time monitoring and machine leaning implementations. An improved correlation for the drift flux parameters is adopted in the model, which enables the utilization of the model for simulating transient flow scenarios for any pipe inclination and extends its applicability to a wider range of conditions. From the formulation, an equation has also been proposed to quantitatively define the application of the concept of slow transient. This equation indicates if a case of interest can be classified as a slow transient, which consequently implies that the use of the proposed model would likely provide accurate results. The model has been validated with experimental and field data, and also compared to the state-of-the-art commercial simulator for transient two-phase flow in pipes. The results showed an agreement within the range of ±30% for the holdup predictions for 65% of the scenarios, and an agreement within the range of ±30% for the pressure predictions for 82% of the scenarios considered in the validation data set. The model performance evaluation with data from a well in the GOM showed a maximum error of 30% in terms of predicted bottomhole pressure and an average error of 9% for the simulation of two years of transient flows.

A New Model for Predicting the Maximum Gas Entrapment Concentration in a Yield Stress Fluid

SPE Journal ◽  
2022 ◽  
pp. 1-15
Author(s):  
Shaowei Pan ◽  
Zhiyuan Wang ◽  
Baojiang Sun
Keyword(s):  
Yield Stress ◽  
Maximum Error ◽  
Critical Distance ◽  
Single Bubble ◽  
Average Error ◽  
Two Phase ◽  
Yield Stress Fluid ◽  
Multiple Bubbles ◽  
Gas Entrapment ◽  
First Time

Summary Gas entrapment is a typical phenomenon in gas-yield stress fluid two-phase flow, and most of the related research focuses on the entrapped condition of the single bubble. However, the amount of entrapped gas, which is more meaningful for engineering, is rarely involved. In this paper, a theoretical model for calculating the maximum gas entrapment concentration (MGEC) is established for the first time. The critical distance between horizontal and vertical entrapped bubbles was determined by the yielded region caused by the buoyancy and the coupled stress field around the multiple bubbles. The MGEC is the ratio of a single bubble volume to its domain volume, which is calculated from the distance between the vertical and the horizontal bubbles. By comparing with the experimental results, the average error of MGEC calculated by this model is 4.42%, and the maximum error is 7.32%. According to the prediction results of the model, an empirical equation that can be conveniently used for predicting MGEC is proposed.

The 3D Numerical Simulation of Flow Field on Y-Shape Flaring Gate Piers Combined with Stepped Spillway

2013 ◽  
Vol 864-867 ◽  
pp. 2200-2206
Author(s):  
Ju Rui Yang ◽  
Xiao Xia Hou ◽  
Qiu Yue Zhang
Keyword(s):  
Water Vapor ◽  
Flow Velocity ◽  
Three Dimensional ◽  
Iterative Solution ◽  
Average Error ◽  
Stepped Spillway ◽  
Two Phase ◽  
Vof Model ◽  
The Right ◽  
Volume Method

The energy dissipater of stepped spillway combined with flaring gate pier is widely used in china's hydraulic engineering. The finite volume method is applied to discrete analysis, with the RNG turbulence model and VOF model of water vapor two-phase, iterative solution of geometry reconstruction format unsteady flow to generate free surface. Adopting structured grid for geometric shape, numerically simulated the water vapor two-phase flow from the reservoir to stilling basin. The parabolic water-vapor interface , overall flow pattern, water wings, section depth and other hydraulic characteristics was produced by simulating the three-dimensional flow field.Compared the simulated results of water depth, flow velocity in stilling pool, the board pressure with experiment data, the average error is: the left side depth of 3 # table hole of 7.1%, and the right of 7.4%; the underside flow velocity of 3 # table hole of 5%;1 # table hole stilling pool board pressure of 7.6%,3 # table hole stilling pool board pressure of 6.6%.

Cinematic Study of Temporomandibular Joint Motion Using Ultra-fast Magnetic Resonance Imaging

CRANIO® ◽  
1999 ◽  
Vol 17 (4) ◽  
pp. 262-267 ◽  
Author(s):  
Armelle Manière-Ezvan ◽  
Thierry Havet ◽  
Jean-Michel Franconi ◽  
Jean-Claude Quémar ◽  
Jacques-Donald de Certaines
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Temporomandibular Joint ◽  
Joint Motion ◽  
Resonance Imaging ◽  
Fast Magnetic Resonance Imaging

Temporomandibular joint motion: efficacy of fast low-angle shot MR imaging.

Radiology ◽  
1989 ◽  
Vol 172 (3) ◽  
pp. 821-826 ◽  
Author(s):  
W F Conway ◽  
C W Hayes ◽  
R L Campbell ◽  
D M Laskin
Keyword(s):  
Mr Imaging ◽  
Temporomandibular Joint ◽  
Joint Motion

Flow Boiling of R134a in Circular Microtubes—Part I: Study of Heat Transfer Characteristics

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Saptarshi Basu ◽  
Sidy Ndao ◽  
Gregory J. Michna ◽  
Yoav Peles ◽  
Michael K. Jensen
Keyword(s):  
Heat Transfer ◽  
Flow Boiling ◽  
Saturation Pressure ◽  
Heat Fluxes ◽  
Average Error ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Mass Fluxes ◽  
Two Phase Heat Transfer

An experimental study of two-phase heat transfer coefficients was carried out using R134a in uniformly heated horizontal circular microtubes with diameters from 0.50 mm to 1.60 mm over a range of mass fluxes, heat fluxes, saturation pressures, and vapor qualities. Heat transfer coefficients increased with increasing heat flux and saturation pressure but were independent of mass flux. The effects of vapor quality on heat transfer coefficients were less pronounced and varied depending on the quality. The data were compared with seven flow boiling correlations. None of the correlations predicted the experimental data very well, although they generally predicted the correct trends within limits of experimental error. A correlation was developed, which predicted the heat transfer coefficients with a mean average error of 29%. 80% of the data points were within the ±30% error limit.

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