scholarly journals A Biomechanical and Thermal Analysis for Bone Augmentation of the Proximal Femur

2018 ◽  
Author(s):  
Amirhossein Farvardin ◽  
Mahsan Bakhtiari Nejad ◽  
Michael Pozin ◽  
Mehran Armand
Keyword(s):  
Proximal Femur ◽  
Maximum Temperature ◽  
Average Error ◽  
Fe Model ◽  
Temperature Profiles ◽  
Bone Augmentation ◽  
Bone Surface ◽  
Promising Tool ◽  
Injection Temperature ◽  
Simulation Results

In this study, we aim to create and validate a Finite Element (FE) model to estimate the bone temperature after cement injection and compare the simulation temperature results with experimental data in three key locations of the proximal femur. Simulation results suggest that the maximum temperature-rise measured at the bone surface is 10°C which occurs about 12 minutes after the injection. Temperature profiles measured during the experiment showed an agreement with those of the simulation with an average error of 1.73 °C Although additional experiments are required to further validate the model, results of this pilot study suggest that this model is a promising tool for bone augmentation planning to lower the risk of thermal necrosis.

Comparison of Crash Test and Simulation Results for Impact of Silverado Pickup into New Jersey Barrier under Manual for assessing Safety Hardware

2012 ◽  
Vol 2309 (1) ◽  
pp. 114-126 ◽  
Author(s):  
Dhafer Marzougui ◽  
Cing-Dao (Steve) Kan ◽  
Kenneth S. Opiela
Keyword(s):  
New Jersey ◽  
Primary Objective ◽  
Crash Test ◽  
Fe Model ◽  
George Washington ◽  
Statistical Measures ◽  
Detailed Simulation ◽  
Analysis Center ◽  
Simulation Results ◽  
Concrete Barrier

The National Crash Analysis Center (NCAC) at the George Washington University simulated the crash of a 2,270-kg Chevrolet Silverado pickup truck into a standard 32-in. New Jersey shape concrete barrier under the requirements of Test 3–11 of the Manual for Assessing Safety Hardware (MASH). The new, detailed finite element (FE) model for the Chevrolet Silverado was used as the surrogate for the MASH 2270P test vehicle. An FE model of the New Jersey barrier was drawn from the array of NCAC hardware models. The primary objective of this analysis was to simulate the crash test conducted to evaluate how this commonly used, NCHRP 350–approved device would perform under the more rigorous MASH crashworthiness criteria. A secondary objective was to use newly developed verification and validation (V&V) procedures to compare the results of the detailed simulation with the results of crash tests undertaken as part of another project. The crash simulation was successfully executed with the detailed Silverado FE model and NCAC models of the New Jersey concrete barrier. Traditional comparisons of the simulation results and the data derived from the crash test suggested that the modeling provided viable results. Further comparisons employing the V&V procedures provided a structured assessment across multiple factors reflected in the phenomena importance ranking table. Statistical measures of the accuracy of the test in comparison with simulation results provided a more robust validation than previous approaches. These comparisons further confirmed that the model was able to replicate impacts with a 2270P vehicle, as required by MASH.

Study on the Thermo-Hydrodynamic of a Dry Gas Seal in Helium Circulator for High Temperature Gas-Cooled Reactor

2011 ◽  
Author(s):  
Jianshu Lin ◽  
Hong Wang
Keyword(s):  
High Temperature ◽  
Film Flow ◽  
Three Dimensional ◽  
Maximum Temperature ◽  
Analysis Method ◽  
Dry Gas Seal ◽  
Safety Requirements ◽  
Simulation Results ◽  
Gas Seals ◽  
High Temperature Gas

A comprehensive analysis method is proposed to resolve the problem of simulating a complex thermo-flow with two kinds of distinct characteristic length in the dry gas seal, and a conjugated simulation of the complicated heat transfer and the gas film flow is carried out by using the commercial CFD software CFX. By using the proposed method, a three dimensional of velocity and pressure field in the gas film flow and the temperature distribution within the sealing rings are investigated for three kinds of film thickness, respectively. A comparison of thermo-hydrodynamics of the dry gas seals is conducted between the sealed gas of air and helium. The latter one is used in a helium circulator for High Temperature Gas-cooled Reactor (HTGR). From comparisons and discussions of a series of simulation results, it will be found that the comprehensive proposal is effective and simulation results are reasonable, and the maximum temperature rise in the dry gas seal is within the acceptable range of HTGR safety requirements.

scholarly journals FINITE ELEMENT ANALYSIS OF THE HEAT TRANSFER IN A PISTON

2020 ◽  
Vol 4 (1) ◽  
pp. 45-51
Author(s):  
Aisha Muhammad ◽  
Shanono Ibrahim Haruna
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Numerical Simulations ◽  
Internal Combustion Engines ◽  
Thermal Stresses ◽  
Maximum Temperature ◽  
Cylinder Wall ◽  
Fe Model ◽  
Piston Cylinder ◽  
Piston Head

The gas expansion process that takes place in a piston cylinder assembly have been used in numerous applications. However, the time-dependent process of heat transfer is still not fully apprehended as the expansion processes are complex and difficult due to the unsteady property of the turbulent flow process. Internal combustion Engines(ICE) designs are conducted with the aim of achieving higher efficiency in the thermal characteristics. To optimize these designs, numerical simulations are conducted. However, modelling of the process in terms of heat transfer and combustion is complex and challenging. For a designer to understand, calculate and quantify the thermal stresses and heat losses at different sections of the structure, understanding the piston-cylinder wall is needed. This study carried out a numerical simulations based on Finite Element Method (FEM) to investigatethe stresses in the piston, and temperature after loading. Appropriate boundary conditions were set on different surfaces for FE model. The study includes the effects of the thermal conductivity of the material of piston, cylinder wall, and connecting rod. Results show the maximum Von-misses stress occurs on the piston head with a value of 3486. 1MPa. The maximum temperature of the piston head and cylinder wall stands at 68.252 and 42.704 degree Celsius respectively.

Dynamic Co-opetitive Network Organization Supported by Multi Agent Architecture

2011 ◽  
pp. 165-183
Author(s):  
Paolo Renna
Keyword(s):  
Simulation Tool ◽  
Informal Networks ◽  
Agent Architecture ◽  
Industrial Economy ◽  
Participation Decision ◽  
Promising Tool ◽  
Multi Agent ◽  
Simulation Results ◽  
Operational Activities ◽  
New Feature

The emergence of institutional or informal networks, formed by cluster groups appears to be a major new feature of the contemporary industrial economy. The focus of this chapter is the development of a Multi Agent Architecture to support a network of enterprises that collaborate in a co-opetition relationships environment. The research concerns the investigation of a life cycle of the network in which the partners change dynamically. In particular, the enterprises that participate in the network can exit or continue to participate, while the enterprises that operate outside the network can evaluate to participate in the network. A simulation environment is developed to implement and test the proposed Multi Agent Architecture. The simulation tool allows to evaluate the proposed approach in a co-opetitive network during the operational activities. The simulation results show that the proposed approach is a very promising tool to support the plant’s participation decision.

scholarly journals Three Alkaloids from an Apocynaceae Species, Aspidosperma spruceanum as Antileishmaniasis Agents by In Silico Demo-case Studies

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 983 ◽  
Author(s):  
Diana Morales-Jadán ◽  
José Blanco-Salas ◽  
Trinidad Ruiz-Téllez ◽  
Francisco Centeno
Keyword(s):  
Free Energy ◽  
Active Site ◽  
In Silico ◽  
Binding Free Energy ◽  
New Drugs ◽  
Neglected Tropical Disease ◽  
Physiological Importance ◽  
Promising Tool ◽  
Binding Pockets ◽  
Simulation Results

This paper is focused on demonstrating with a real case that Ethnobotany added to Bioinformatics is a promising tool for new drugs search. It encourages the in silico investigation of “challua kaspi”, a medicinal kichwa Amazonian plant (Aspidosperma spruceanum) against a Neglected Tropical Disease, leishmaniasis. The illness affects over 150 million people especially in subtropical regions, there is no vaccination and conventional treatments are unsatisfactory. In attempts to find potent and safe inhibitors of its etiological agent, Leishmania, we recovered the published traditional knowledge on kichwa antimalarials and selected three A. spruceanum alkaloids, (aspidoalbine, aspidocarpine and tubotaiwine), to evaluate by molecular docking their activity upon five Leishmania targets: DHFR-TS, PTR1, PK, HGPRT and SQS enzymes. Our simulation results suggest that aspidoalbine interacts competitively with the five targets, with a greater affinity for the active site of PTR1 than some physiological ligands. Our virtual data also point to the demonstration of few side effects. The predicted binding free energy has a greater affinity to Leishmania proteins than to their homologous in humans (TS, DHR, PKLR, HGPRT and SQS), and there is no match with binding pockets of physiological importance. Keys for the in silico protocols applied are included in order to offer a standardized method replicable in other cases. Apocynaceae having ethnobotanical use can be virtually tested as molecular antileishmaniasis new drugs.

Thermal Analysis of Laser Irradiation of Fused Silica

2011 ◽  
Vol 314-316 ◽  
pp. 1960-1964 ◽  
Author(s):  
Peng Yao ◽  
Ya Dong Gong ◽  
Suo Xian Yuan ◽  
Tian Feng Zhou ◽  
Ji Wang Yan ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Surface Roughness ◽  
Laser Irradiation ◽  
Fused Silica ◽  
Maximum Temperature ◽  
Precision Grinding ◽  
Micro Cracks ◽  
Ductile Mode ◽  
Ultra Precision ◽  
Simulation Results

To grind fused silica in ductile mode, surface and subsurface micro cracks (SSMC) on ground fused silica should be repaired by CO2 laser irradiation before ultra-precision grinding. In this paper, 2D thermal analysis of single pass laser irradiation of fused silica was conducted, and the simulation results were discussed by comparing with the experiment results. To repair SSMC and decrease the surface roughness of ground fused silica simultaneously, the maximum temperature on the surface during laser irradiation should be controlled higher than 3280 K and lower than 3550 K.

A Conductive Cooling Scheme for Bone Augmentation of the Proximal Femur With PMMA: An Experimental and Finite Element Study

2019 ◽  
Author(s):  
Mahsan Bakhtiarinejad ◽  
Amirhossein Farvardin ◽  
Alireza Chamani ◽  
Mehran Armand
Keyword(s):  
Finite Element ◽  
Cooling System ◽  
Peak Temperature ◽  
Curing Temperature ◽  
Maximum Temperature ◽  
Data Simulation ◽  
Cement Injection ◽  
Simulation Results ◽  
One Year ◽  
Ice Water

Abstract The rate of one-year mortality after osteoporotic hip fracture in elderly is reported to be more than 20%. Hip augmentation using polymethylmethacrylate (PMMA) is an alternative preventive approach for patients at the highest risk of osteoporotic fracture. Excessive injection volumes of PMMA however may introduce the risk of thermal osteonecrosis. We have previously proposed a Finite element (FE) simulation to estimate the bone temperature elevations after cement injection in three key locations and demonstrated an agreement between the simulation results and the temperature measurements during the experiment. Previous study showed that the maximum temperature-rise measured at the hip surface is 10°C. The aim of this study is to introduce a cooling approach to reduce the PMMA’s curing temperature after cement injection during hip augmentation. For this purpose, we perform a conductive cooling experiment with a metallic K-wire attached to an ice-water bath. We also create a finite element simulation model for the proposed cooling system to estimate the peak temperature reduction and compare the simulation results with experimental data. Simulation results demonstrate the decrease of 80% of peak curing temperature during PMMA polymerization; similarly, sawbone experiments also show that on average the peak temperature has been reduced 64% when cooling system is integrated to the hip augmentation procedure.

scholarly journals A Three-Dimensional Finite-Element Model of a Human Dry Skull for Bone-Conduction Hearing

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Namkeun Kim ◽  
You Chang ◽  
Stefan Stenfelt
Keyword(s):  
Finite Element ◽  
Bone Conduction ◽  
Three Dimensional ◽  
Human Head ◽  
Element Model ◽  
Fe Model ◽  
Lateral Direction ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Three Dimensional Finite Element

A three-dimensional finite-element (FE) model of a human dry skull was devised for simulation of human bone-conduction (BC) hearing. Although a dry skull is a simplification of the real complex human skull, such model is valuable for understanding basic BC hearing processes. For validation of the model, the mechanical point impedance of the skull as well as the acceleration of the ipsilateral and contralateral cochlear bone was computed and compared to experimental results. Simulation results showed reasonable consistency between the mechanical point impedance and the experimental measurements when Young’s modulus for skull and polyurethane was set to be 7.3 GPa and 1 MPa with 0.01 and 0.1 loss factors at 1 kHz, respectively. Moreover, the acceleration in the medial-lateral direction showed the best correspondence with the published experimental data, whereas the acceleration in the inferior-superior direction showed the largest discrepancy. However, the results were reasonable considering that different geometries were used for the 3D FE skull and the skull used in the published experimental study. The dry skull model is a first step for understanding BC hearing mechanism in a human head and simulation results can be used to predict vibration pattern of the bone surrounding the middle and inner ear during BC stimulation.

Simulation on Flow Field and Temperature Field in Water Cooling Tuyere of Blast Furnace

2013 ◽  
Vol 753-755 ◽  
pp. 2709-2712 ◽  
Author(s):  
Ya Na Qie ◽  
Shu Hui Zhang ◽  
Qing Lv ◽  
Li Hong Zhang
Keyword(s):  
Temperature Field ◽  
Economic Benefit ◽  
Cfd Simulation ◽  
Water Pressure ◽  
High Yield ◽  
Maximum Temperature ◽  
Water Cooling ◽  
Direct Motion ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

Life span of water cooling tuyere is one of important factors of blast furnace’s direct motion and high yield. In order to improve the life of tuyere, the flow fleld and temperature field of tuyere were simulated by using computational fluid dynamics (CFD). Simulation results show that the maximum temperature appears at the front margin of tuyere outlet side. The highest temperature of tuyere reduces significantly with the increase of water pressure below 0.4MPa. When the water pressure exceeds 0.4Pa, the highest temperature reduces slowly. In consideration of economic benefit and cooling effect, the best point of inlet pressure is 0.4MPa or so.

Evolution of Temperature Profiles during Stress-Induced Transformation in NiTi Thin Films

2013 ◽  
Vol 738-739 ◽  
pp. 287-291 ◽  
Author(s):  
Berthold Krevet ◽  
Viktor Pinneker ◽  
Magnus Rhode ◽  
Christoph Bechthold ◽  
Eckhard Quandt ◽  
...  
Keyword(s):  
Temperature Compensation ◽  
Room Temperature ◽  
Tensile Loading ◽  
Element Model ◽  
Maximum Temperature ◽  
Strain Rates ◽  
Temperature Profiles ◽  
Temperature Decrease ◽  
Time Resolved ◽  
Local Generation

This paper presents a time-resolved investigation of tensile loading induced temperature profiles in pseudoelastic NiTi thin film specimens. A finite element model for coupled mechanical and time dependent thermal analysis is presented that accounts for the different effects of local generation of latent heat and heat transfer. For strain rates larger than 0.24/s, the maximum temperature increases from room temperature to above 50 °C. Subsequent stress relaxation after temperature compensation results in a temperature decrease from room temperature down to -20 °C. The observed evolution of temperature profiles is in qualitative agreement with infrared thermography experiments on NiTi films fabricated by magnetron sputtering.

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