scholarly journals 3-Dimensional Physiologic Postural Range of the Mandible: A Computerized-Assisted Technique—A Case Study

2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Todd Shewman
Keyword(s):  
Muscle Activity ◽  
3 Dimensional ◽  
Spatial Range ◽  
Physiologic Parameters ◽  
Closed Position ◽  
Jaw Position ◽  
Spatial Kinematics ◽  
Open Position ◽  
Antagonistic Muscles

Previous studies demonstrated that while the mandible assumes its resting position in space, antagonistic muscles should assume minimal muscle activity within a spatial range. This zone of mandibular rest has been mapped using physiologic parameters of muscle activity and incisal spatial kinematics. This case study expands on previous research by monitoring incisal and posterior jaw position and includes lateral pterygoid muscle activity, thus allowing for determining the spatial range including additional relevant coordinates and muscle activity. Four positions were evaluated: a maximum physiologic open position, a maximum physiologic closed position, physiologic rest position, and maximum physiologic protrusion position. Within the physiologic zone of rest formed by these 4 positions, the vertical and anterior borders of the envelope of function may be documented for the incisal and posterior mandible in true 3-dimensional fashion to assist the clinician in determining a physiologic interocclusal freeway space and vertical dimension of occlusion. Advantages and limitations are discussed.

Valve Operability During a Fire

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Karan Sotoodeh
Keyword(s):  
Thermal Expansion ◽  
The Body ◽  
Valve Body ◽  
Gas Processing ◽  
Oil Export ◽  
Closed Position ◽  
Fire And Explosion ◽  
Open Position ◽  
Refinery Gas

Fire and explosion are a major cause of concern for refinery, gas processing, petrochemical, and gas installations. The safest way to deal with a fire is to prevent it. However, fire prevention strategies are not always successful, and fires can happen. Therefore, valves should be designed and tested to be fire-safe. This paper reviews valve design features that can help prevent fires, including secondary sealing between the ball and body in case of losing a soft seat, a graphite fire-safe ring design for stem and seat sealing, antistatic devices, and antistatic tests to ensure that the valve is fire-safe. In addition to design considerations, a fire-safe design should be validated through tests defined in standards such as API 607, API RP 6FA, and ISO 10497. The API RP 6FA tests reviewed in this paper include seven tests that check the operability of the valve from closed to open position. A case study was done to prove the operability of a fail close 38″ pipeline ball valve on an oil export pipeline in case of fire during the first 20 s from the open to the closed position. Thermal analysis on the body of the valve proved that there was no thermal expansion inside the valve after 150 s of fire. Additionally, the maximum radial displacement on the valve body after 150 s of fire was 0.34 mm which is negligible. Thus, the valve thermal expansion did not disturb the operation of the valve after 20 s.

scholarly journals Clinical Use of Surface Electromyography to Track Acute Upper Extremity Muscle Recovery after Stroke: A Descriptive Case Study of a Single Patient

2021 ◽  
Vol 4 (2) ◽  
pp. 32
Author(s):  
Heather A. Feldner ◽  
Christina Papazian ◽  
Keshia M. Peters ◽  
Claire J. Creutzfeldt ◽  
Katherine M. Steele
Keyword(s):  
Muscle Activity ◽  
Surface Electromyography ◽  
Inpatient Rehabilitation ◽  
Stroke Survivor ◽  
Structured Interview ◽  
Routine Care ◽  
Stroke Recovery ◽  
Descriptive Case Study ◽  
Sensing Technology

Arm recovery varies greatly among stroke survivors. Wearable surface electromyography (sEMG) sensors have been used to track recovery in research; however, sEMG is rarely used within acute and subacute clinical settings. The purpose of this case study was to describe the use of wireless sEMG sensors to examine changes in muscle activity during acute and subacute phases of stroke recovery, and understand the participant’s perceptions of sEMG monitoring. Beginning three days post-stroke, one stroke survivor wore five wireless sEMG sensors on his involved arm for three to four hours, every one to three days. Muscle activity was tracked during routine care in the acute setting through discharge from inpatient rehabilitation. Three- and eight-month follow-up sessions were completed in the community. Activity logs were completed each session, and a semi-structured interview occurred at the final session. The longitudinal monitoring of muscle and movement recovery in the clinic and community was feasible using sEMG sensors. The participant and medical team felt monitoring was unobtrusive, interesting, and motivating for recovery, but desired greater in-session feedback to inform rehabilitation. While barriers in equipment and signal quality still exist, capitalizing on wearable sensing technology in the clinic holds promise for enabling personalized stroke recovery.

scholarly journals An empirical study on open position risk assessment using VAR and regression analysis: A case study of Iranian banking industry

2012 ◽  
Vol 2 (6) ◽  
pp. 2135-2140 ◽  
Author(s):  
Mohammad Khodaei Valahzaghard ◽  
Mina Ghavidel ◽  
Mojtaba Heidar ◽  
Elmira Mahmoudzadeh
Keyword(s):  
Risk Assessment ◽  
Regression Analysis ◽  
Empirical Study ◽  
Banking Industry ◽  
Open Position

Wing Mechanics and Take-Off Preparation of Thrips (Thysanoptera)

1980 ◽  
Vol 85 (1) ◽  
pp. 129-136 ◽  
Author(s):  
C. P. ELLINGTON
Keyword(s):  
Leading Edge ◽  
Morphological Features ◽  
Inertial Forces ◽  
Wing Area ◽  
Trailing Edge ◽  
Lateral Projection ◽  
Parking Problem ◽  
Closed Position ◽  
Open Position ◽  
Fringe System

1. All of the wing fringe cilia of Thrips physapus, except those along the hindwing leading edge, pivot in elongated sockets which lock them into two positions. 2. The wings lie parallel over the abdomen when not in use, with the cilia locked in the closed position at an angle of 15-20° to the wing axis. The closing of the fringes prevents entanglement of the trailing edge cilia and lateral projection of the forewing leading edge cilia. 3. During flight the cilia are locked in the open position, doubling the wing area. The locking force is stronger than the combined aerodynamic and inertial forces on the cilia. 4. The fringes are opened by abdominal combing and closed by tibial combing. 5. The same morphological features are found in other members of the sub-order Terebrantia. Parallel wings at rest are characteristic of this suborder, and the collapsible fringe system is viewed as an effective method for parking the wings. 6. The fringes of the sub-order Tubulifera are not collapsible. The wings overlap on the abdomen at rest and a similar parking problem does not arise.

Modelling Techniques and Case Study of Explicit 3D FE-Simulation of Ridge Loads Against an Offshore Structure

2009 ◽  
Author(s):  
Jaakko Heinonen
Keyword(s):  
Friction Angle ◽  
Material Model ◽  
Dimensional Structure ◽  
Constant Thickness ◽  
Fe Model ◽  
Offshore Structure ◽  
3 Dimensional ◽  
Modelling Techniques ◽  
User Material Subroutine

A ridge interaction with an offshore structure, Norstro¨msgrund lighthouse in the Gulf of Bothnia, was simulated by the finite element method (FEM) utilizing the explicit solution algorithm. The explicit method in a dynamic analysis enabled an efficient way to simulate the failure of a ridge. A shear-cap material model describing the ice rubble mechanical behaviour was developed for the 3-dimensional analysis and implemented into ABAQUS FEM-software as a user material subroutine. The FE-model described the ridge: the sail and keel consisting of ice rubble and the consolidated layer close to the waterline. A selected ridge-interaction event was simulated with a simplified geometry, based on measurements carried out in the STRICE project. The ridge field was idealized to have a constant thickness. The shape of a 3-dimensional structure was modelled using rigid elements. The phenomenological model can be utilized to gain an understanding of how the ridge fails during the interaction with an offshore structure, what the ridge loads are, and how they are distributed against the structure. A parametric study was carried out to study how the mechanical properties, i.e. the cohesion and friction angle of the rubble and the strength of the consolidated layer influence the forces and failure mechanisms.

Probability of Uncontrolled External Leakage During the Production Phase of a Subsea Well

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
André L. R. Alves ◽  
T. A. Netto
Keyword(s):  
Failure Modes ◽  
Base Case ◽  
Component Reliability ◽  
Production Phase ◽  
Distribution Parameters ◽  
Common Cause Failures ◽  
Integrity Management ◽  
Closed Position ◽  
The Impact

Abstract This work presents a methodology for evaluating the uncontrolled external leakage probability of a subsea well during the production phase. Based on a barrier diagram, an algorithm for possible leak path identification is proposed, considering different operation modes: gas lift operation, free-flowing, or well closed at the subsea Christmas tree. Considering the equivalency between these paths and the minimum cut sets from a fault tree modeling, the uncontrolled external leakage probability is calculated using the upper bound approximation. The effect of common cause failures is considered for the failure mode fail-to-close-valve. The instantaneous availability function of each component is considered. Non-repairable, repairable, and periodically tested items are used. Probability distribution parameters are estimated in order to make a case study. The failure rate functions determined are used as input for the proposed model, regarding the following failure modes: fail-to-close, external-leakage, and internal-leakage at the closed position. Finally, failure probability results and sensitivity analysis are demonstrated for a base case study. Parameters like time between tests, inspections, and component reliability are varied in order to identify the impact on the uncontrolled external leakage probability. The main objective of the proposed methodology is to support decision-making on the well integrity management system during the production phase of a subsea well. To this end, actual and reliable input data should be considered.

scholarly journals Evaluation of Seabed Stability and Scour Control Around Subsea Gravity Protection Structures

2010 ◽  
Author(s):  
Richard J. S. Whitehouse ◽  
Carlos Lam ◽  
Stephen Richardson ◽  
Peter Keel
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
North Sea ◽  
Cfd Analysis ◽  
Cfd Model ◽  
3 Dimensional ◽  
Computational Fluid Dynamics Cfd ◽  
The Uk ◽  
Study Application

Results from an advanced 3-dimensional Computational Fluid Dynamics (CFD) model have proven to form an effective basis on which to design stable and scour resistant subsea structures in areas of seabed which are prone to scouring. A case study application from the UK sector of the southern North Sea is presented to demonstrate the benefits of the CFD analysis.

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