Review of Cardiac Pacemaker Lead Designs for Computational Models in a VR Environment

2017 ◽  
Author(s):  
Bethany Tourek ◽  
Dan Orban ◽  
Lingyu Meng ◽  
Hakizumwami Birali Runesha ◽  
Dan Keefe ◽  
...  
Keyword(s):  
Computational Models ◽  
Cardiac Pacemaker ◽  
Model Complexity ◽  
Element Analysis ◽  
Parameterized Design ◽  
Pacemaker Leads ◽  
Computational Fluid Dynamics Cfd ◽  
The Right ◽  
Implantable Cardiac Pacemaker ◽  
Computational Resources

An implantable cardiac pacemaker is used to modify and treat irregular heartbeats [1] and invented in 1958 [2]. Devices have no fixation or fixed to the heart wall. No fixation leads lay in the bottom of heart cavities, while fixed leads have tines (passive) or a helix screw (active) to attach to the heart. Lead geometries and material properties vary between companies, with geometric sizing based primarily on the internal mechanics of the lead. Finite element analysis (FEA), computational fluid dynamics (CFD) and bench-top simulations are used to evaluate cardiac leads. These simulations analyze only one lead and struggle to compare and test variations in lead designs. Advanced computational resources can run many computer simulations of anatomical environments, however model complexity increases the time to run each simulation. To address this issue, we present a simplified parameterized design space for cardiac pacemaker leads in the right atrium. This information will be used to run multiple simulations of leads in blood flow, for visualization in a single virtual reality (VR) environment and allow the designer to iterate through many design variations (See Figure 1).

scholarly journals Experimental and Numerical Analysis of Deformation in a Rotating RC Helicopter Blade

2020 ◽  
Vol 5 (3) ◽  
pp. 13
Author(s):  
Pedro J. Sousa ◽  
Francisco Barros ◽  
Paulo J. Tavares ◽  
Pedro M. G. P. Moreira
Keyword(s):  
Computational Models ◽  
Measurement Techniques ◽  
Image Correlation ◽  
Element Analysis ◽  
Helicopter Blade ◽  
Structure Interaction ◽  
Image Sensing ◽  
3D Digital Image Correlation ◽  
Out Of Plane ◽  
Computational Fluid Dynamics Cfd

Rotating structures are important and commonly used in the transportation and energy generation fields, where a better understanding of the deformations these structures endure is essential for both the design and maintenance phases. This work presents a novel image sensing methodology for measuring the displacements of rotating parts in operation due to dynamic loading. This methodology employs 3D digital image correlation combined with a custom stroboscopic lighting solution to achieve apparent stillness of the target while it rotates and then processes the acquired data to remove small imprecisions and align it to the rotor’s intrinsic coordinate system. It was applied to an RC helicopter, whose blade deformation was measured and compared with a computational model, using fluid–structure interaction between computational fluid dynamics (CFD) and finite element analysis (FEA). Using live measurement techniques, it was possible to obtain the actual behaviour of the blades, which can be used to validate and tune computational models. The proposed methodology complements the methods available in the literature, which were centred around relative out-of-plane displacements, by enabling the comparison of absolute out-of-plane and in-plane ones.

Addressing Shell Mode Vibration in Ducts in Refinery With Computational Models and Field Data

2019 ◽  
Author(s):  
Ishita Chakraborty ◽  
Anup Paul ◽  
Gyorgy Szasz
Keyword(s):  
Computational Models ◽  
Field Measurements ◽  
Operating Conditions ◽  
Flow Induced Vibration ◽  
Element Analysis ◽  
Vibration Data ◽  
Response Data ◽  
Design Changes ◽  
Mode Vibration ◽  
Computational Fluid Dynamics Cfd

Abstract This paper describes the work performed to study the shell mode vibration of a large cross-section flue gas duct. The work involved the collection of field vibration data, as well as predictive computational models associated with finite element analysis (FEA) and computational fluid dynamics (CFD). The goal of this work was to use predictive models to ascertain whether a proposed design change would reduce the vibration levels of the duct under similar operating conditions. The vibration observed in the duct was identified as a flow induced vibration (FIV) which excited the shell modes of the duct walls. This case study serves as an example of using predictive computational models (FEA and CFD), calibrated with vibration response data from field measurements, to represent the real world situation as closely as possible within specified budget and schedule constraints. Such calibrated models can be useful for forecasting the effectiveness of various proposed design changes.

Using Virtual Engineering Tools to Reduce NOx Emissions

2004 ◽  
Author(s):  
Douglas S. McCorkle ◽  
Kenneth M. Bryden ◽  
David A. Swensen
Keyword(s):  
Power Plants ◽  
Computational Models ◽  
Successful Implementation ◽  
Data Sets ◽  
Virtual Engineering ◽  
Thermal Fluids ◽  
Computational Fluid Dynamics Cfd ◽  
Reduction Of Nox ◽  
Computational Resources ◽  
Extensible Software

The use of computational fluid dynamics (CFD) to improve an engineer’s understanding of methods to reduce NOxemissions is becoming more prevalent as high-end computational resources become more economically accessible. These trends have allowed engineers to better design and improve the efficiency of power plants and thus reduce NOx. While these computational models have proven very useful over the past few years, the full extent to which they can be used to gain a better intuition about a design has not been fully explored. One such way to extract more information from these simulations is to use virtual engineering tools to interrogate these models. Currently, there are many virtual engineering tools that are being developed to facilitate the investigation of power plant systems. One such suite of virtual engineering tools is called Virtual Engineering Suite (VE-Suite). The capabilities of this suite include rapid CFD recalculation, optimization routines for large thermal fluids systems, coupling of multiple computational resources, hybrid CFD solvers, interaction with multiple CFD data sets, and manipulation of system geometry. VE-Suite is discussed as an initial platform for this integrated hierarchy of models that can provide a foundation for virtual engineering. VE-Suite has an extensible software architecture and is composed of several tools including VE-Builder, VE-Conductor, VE-Explorer, VE-Designer, and a Computational Engine. One example of the potential use of these virtual engineering tools in the reduction of NOx is presented. In addition, the factors for successful implementation of future virtual engineering tools for the reduction of NOx are proposed.

Sail Aero-Structures: Studying Primary Load Paths and Distortion

2005 ◽  
Author(s):  
Robert Ranzenbach ◽  
Zhenlong Xu
Keyword(s):  
Aerodynamic Load ◽  
Element Analysis ◽  
Strain Behavior ◽  
Construction Methods ◽  
Load Paths ◽  
Calculation Results ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Field ◽  
The Impact ◽  
Primary Load

A method is described to conduct an integrated Fluid-Structure Interaction (FSI) simulation of sails that is based upon knowledge of the sail’s design shape geometry and membrane material properties. A Finite Element Analysis (FEA) of the sail structure and a Computational Fluid Dynamics (CFD) model of the aerodynamic field are combined and iteratively solved to compute the actual flying shape of the sail under aerodynamic load, the stress strain behavior of the sail membrane, the integrated aerodynamic forces produced by the sail such as driving force and heel moment, and the resulting loads on sheets, halyards, etc. An important contribution of this particular method is the incorporation of wrinkling phenomena into the FEA portion of the calculation. Results from a study of working sails for a 30’ MORC racing yacht designed by Nelson-Marek (NM) in the 1990’s are presented and discussed with particular emphasis on the variability of primary load paths with changing trim and sailing conditions as well as the impact of sail deformation in the direction of relatively small stresses that is often poorly addressed in many proprietary sail construction methods.

Development of 1500-r/min 75-Inch Ultra-Long Last Stage Blades for Nuclear Steam Turbine

2017 ◽  
Author(s):  
Deqi Yu ◽  
Jiandao Yang ◽  
Wei Lu ◽  
Daiwei Zhou ◽  
Kai Cheng ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Vibration Monitoring ◽  
Steam Turbines ◽  
Element Analysis ◽  
Rotating Blade ◽  
Lifetime Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Last Stage

The 1500-r/min 1905mm (75inch) ultra-long last three stage blades for half-speed large-scale nuclear steam turbines of 3rd generation nuclear power plants have been developed with the application of new design features and Computer-Aided-Engineering (CAE) technologies. The last stage rotating blade was designed with an integral shroud, snubber and fir-tree root. During operation, the adjacent blades are continuously coupled by the centrifugal force. It is designed that the adjacent shrouds and snubbers of each blade can provide additional structural damping to minimize the dynamic stress of the blade. In order to meet the blade development requirements, the quasi-3D aerodynamic method was used to obtain the preliminary flow path design for the last three stages in LP (Low-pressure) casing and the airfoil of last stage rotating blade was optimized as well to minimize its centrifugal stress. The latest CAE technologies and approaches of Computational Fluid Dynamics (CFD), Finite Element Analysis (FEA) and Fatigue Lifetime Analysis (FLA) were applied to analyze and optimize the aerodynamic performance and reliability behavior of the blade structure. The blade was well tuned to avoid any possible excitation and resonant vibration. The blades and test rotor have been manufactured and the rotating vibration test with the vibration monitoring had been carried out in the verification tests.

Finite Element Calculation and Pushing Construction Analysis on the Superstructure of Beijiang Auxiliary Channel Bridge

2012 ◽  
Vol 204-208 ◽  
pp. 2167-2171
Author(s):  
Yu Lan Wang ◽  
Guo Dong Zheng
Keyword(s):  
Finite Element ◽  
Reference Value ◽  
Construction Process ◽  
Element Calculation ◽  
Box Girders ◽  
Element Analysis ◽  
Shrinkage And Creep ◽  
Load Effects ◽  
Live Loads ◽  
The Right

Finite element analysis and calculation are held on the superstructure of the auxiliary channel bridge at the right branching of Beijiang Bridge for a short condition and the service phase. The theoretical launching force is calculated and amended in construction. The results show that when considering load effects such as the dead loads of box girders, the live loads of decks and the pre-stressed secondary forces, the eccentric stress state will appear on the webs, and the steel stress produced by shrinkage and creep of concrete can not be ignored. So the launching force must be amended during the construction process. These conclusions have a certain reference value on the bridge design and construction.

Giant Pseudoaneurysm of the Extracranial Vertebral Artery Successfully Treated Using Intraoperative Balloon Catheters

Neurosurgery ◽  
1991 ◽  
Vol 28 (5) ◽  
pp. 738-742 ◽  
Author(s):  
Junya Hanakita ◽  
Hideyuki Suwa ◽  
Kiyoshi Nishihara ◽  
Koji Iihara ◽  
Hiroshi Sakaida
Keyword(s):  
Vertebral Artery ◽  
Cardiac Pacemaker ◽  
Innominate Artery ◽  
Anatomical Location ◽  
High Morbidity ◽  
Vertebrobasilar System ◽  
Balloon Catheters ◽  
Extracranial Vertebral Artery ◽  
The Right ◽  
Giant Pseudoaneurysm

Abstract Traumatic pseudoaneurysms of the extracranial vertebral artery rarely occur, because of its deeply protected anatomical location. Because the direct surgical approach has resulted in high morbidity and mortality rates, ligation of the vertebral artery has been adopted, but this can cause an ischemia in the vertebrobasilar system. We report the case of a 73-year-old woman with a huge pseudoaneurysm of the right vertebral artery that occurred after attempted placement of a cardiac pacemaker. The aneurysm was 7 x 7 x 5 cm in size and its neck was situated just distal to the right subclavian artery. Direct surgical repair of the injured vessel and removal of the aneurysm were successfully performed using balloon catheters placed intraoperatively in both the innominate artery and the right vertebral artery.

scholarly journals Design and Simulation of Nozzle for Pure Water Jet Portable Cutting Tool

2019 ◽  
Vol 8 (12S2) ◽  
pp. 703-706
Keyword(s):  
Pressure Drop ◽  
Cross Sections ◽  
Pure Water ◽  
Water Jet ◽  
Element Analysis ◽  
Cutting Machine ◽  
Water Jet Cutting ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
The Impact

A pure water jet at subsonic speed provides an opportunity for application in cutting soft material with the advantage of not contaminating the workpiece. Inside the nozzle, water is flowing through various cross sections, which lead to pressure drop and loss of energy. This requires a nozzle with a design that causes minimum pressure drop. In this work, Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) were used to analyse the flow through five different nozzles. For each nozzle, the pressures of 10 MPa, 20 MPa and 30 MPa were applies at the inlet. For the inlet pressure of 10 MPa, the highest outlet velocity us 136.12 m/s at the pressure of 9.261 MPa. The impact pressure at stand distance of 0.5 mm and 1.0 mm were 8.26 MPa and 8.02 MPa, respectively. For this nozzle, the Factor of Safety for 10 MPa, 20 MPa and 30 MPa were 6.4, 3.2 and 2.961, respectively. The findings are relevant to the development of pure water jet cutting machine

scholarly journals Characteristics and Dynamics of Full Arch Distalization Using Transpalatal Arches with Midpalatal and Interradicular Miniscrews as Temporary Anchorage Devices: A Preliminary Finite Element Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Mashallah Khanehmasjedi ◽  
Sepideh Bagheri ◽  
Vahid Rakhshan ◽  
Mojtaba Hasani
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Orthodontic Appliances ◽  
Element Analysis ◽  
Midpalatal Suture ◽  
Second Molar ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
The Right

Introduction. Miniscrews have proved quite effective in fixed orthodontic treatment. They can be placed in areas like palatal interradicular zones or midpalatal suture. Despite the value of these methods and their ever-increasing use, their characteristics are not assessed before when implanted in palatal interradicular areas or in the midpalatal suture. We aimed to assess, for the first time, the dynamics of full arch distalization using such miniscrews. Methods. A 3D model of maxilla with all permanent dentition was created from a CT scan volume. Tissues were segmented and differentiated. Afterward, miniscrews and appliances were designed, and the whole model was registered within a finite element analysis software by assigning proper mechanical properties to tissues and orthodontic appliances. The full arches were distalized using transpalatal arches with miniscrews as anchorage devices (in two different models). The extents of stresses and patterns of movements of various elements (teeth, miniscrews, appliances, tissues) were estimated. Results and Conclusions. Comparing the two models, it is obvious that in both models, the stress distribution is the highest in the TPA arms and the head of the miniscrew where the spring is connected. In comparison with the displacement in the X-axis, the “mesial in” rotation is seen in the first molar of both models. But there is one exception and that is the “mesial out” rotation of the right second molar. In all measurements, the amount of movement in Model 2 (with palatal interradicular miniscrews) is more than that in Model 1 (with midpalatal miniscrew). In the Y-axis, more tipping is seen in Model 2, especially the anterior teeth (detorque) and the first molar, but in Model 1, bodily movement of the first molar is more evident. Along the Z-axis, the mesial intrusion of the first molar and the distal extrusion of this tooth can be seen in both models. Again, the displacement values are higher in the second model (with interradicular miniscrews). In comparison with micromotion and stress distribution of miniscrews, in Model 1, maximum stress and micromotion is observed at the head of the miniscrew where it is attached to the spring. Of course, this amount of micromotion increases over time. The same is true for Model 2, but with a lower micromotion. As for the amount of stress, the stress distribution in both miniscrews of both models is almost uniform and rather severe.

scholarly journals Persistent Cutibacterium (Formerly Propionibacterium) acnes Bacteremia and Refractory Endocarditis in a Patient with Retained Implantable Pacemaker Leads

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
M. Freedman ◽  
J. O. Aflatooni ◽  
R. Foster ◽  
P. G. Haggerty ◽  
C. J. Derber
Keyword(s):  
Electronic Device ◽  
Cardiac Pacemaker ◽  
Etiologic Agent ◽  
Implantable Devices ◽  
Blood Cultures ◽  
Cardiac Device ◽  
Pacemaker Leads ◽  
Lead Endocarditis ◽  
Positive Results ◽  
Implantable Pacemaker

Cutibacterium (formerly Propionibacterium) acnes (C. acnes) is a commensal bacteria commonly found on the human skin and in the mouth. While the virulence of C. acnes is low in humans, it does produce a biofilm and has been identified as an etiologic agent in a growing number of implant-associated infections. C. acnes infections can prove diagnostically challenging as laboratory cultures can often take greater than 5 days to yield positive results, which are then often disregarded as contaminant. Patients with recurrent bacteremia in the setting of implantable devices warrant further studies to evaluate for an associated valvular or lead endocarditis. The patient in this report demonstrates how cardiac device-related endocarditis secondary to C. acnes can be overlooked due to the indolent nature of this pathogen. This patient presented with an implanted cardiac pacemaker device, as well as retained leads from a prior pacemaker. Transesophageal echocardiography was required to confirm the diagnosis in the setting of multiple positive blood cultures and negative transthoracic echocardiograms over a period of 4 years. The purpose of this report is to highlight the difficulties encountered in diagnosing C. acnes endocarditis in a patient with a cardiac implantable electronic device and persistently positive blood cultures.

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