scholarly journals A TWO-DIMENSIONAL THERMODYNAMIC MODEL TO PREDICT HEART THERMAL RESPONSE DURING OPEN CHEST PROCEDURES

2016 ◽  
Vol 15 (1) ◽  
pp. 44
Author(s):  
F. G. Dias ◽  
J. V. C. Vargas ◽  
M. L. Brioschi
Keyword(s):  
Cardiac Surgery ◽  
Temperature Distribution ◽  
Thermodynamic Model ◽  
Thermal Effects ◽  
Computational Simulation ◽  
Thermal Response ◽  
Cardiac Response ◽  
The Finite Element Method ◽  
Thermal Distribution ◽  
Open Chest

In this work, the temperature distribution of the heart in an open chest surgery scenario is studied. It is also evaluated the cardiac thermal effects of the injection of a cooling liquid in the aorta root, which is used in infrared thermography. The finite element method was used to develop a model that predicts the temperature distribution modification in a 2-dimensional slice of the heart. This thermodynamic model allows the computational simulation of the thermal cardiac response to open chest procedures, which are required by cardiac surgery. The influence of several operating parameters (e.g., coronary flow rate, temperature) on the resulting thermal distribution is analyzed. Therefore, this analysis allows the identification of parameters that could be controlled to minimize the loss of energy, and consequently, avoiding the hazardous thermal distribution that could put the heart in danger during cardiac surgery.

scholarly journals Measurement of Windage Losses and Temperature Distribution for a High Speed Composite Rotor in a Stator Assembly at Low Air Pressures

2003 ◽  
Author(s):  
Jonathan Hahne ◽  
Mike Werst ◽  
Charles Penney ◽  
Hsing-Pang Liu ◽  
Jeremy O’Rarden ◽  
...  
Keyword(s):  
Experimental Data ◽  
Temperature Distribution ◽  
Thermal Effects ◽  
High Speed ◽  
Operating Conditions ◽  
Heat Distribution ◽  
Loss Analysis ◽  
Thermal Distribution ◽  
Specific Geometry ◽  
Proper Design

With the advancements in composite technology several innovative applications present themselves that involve high-speed composite rotors spinning in a stator assembly. As rotational speeds and rotor tip speeds increase, these rotors must operate in low air pressure environments to minimize windage losses and thermal effects of being at high speed for long durations. Accurately predicting this windage loss for a specific geometry and operating conditions is very important for a proper design. It is also very important to know the relative heat distribution that is seen by the rotor and stator from this windage loss. Analysis tools to date do not have a coupled link that calculates windage loss and a resultant thermal distribution to the rotor and stator surfaces. This paper presents the design and fabrication of a test setup to measure the total windage loss and temperature distribution from a high-speed composite rotor in a stator structure. Rotor speeds up to 40,000 rpm and rotor tip speeds up to 900 m/s with pressure ranges from 0.1 torr to 10 torr were operating parameters during the testing. The paper will also present experimental data obtained during the testing. Experimental data obtained during the testing will be used to evaluate new analysis methods for predicting the windage loss and thermal distribution in new high-speed rotor applications.

scholarly journals Influence of Sternotomy on Delta Pulse Pressure and Delta Down During Open Chest Cardiac Surgery: A Preliminary Study

2019 ◽  
Vol 33 (8) ◽  
pp. 2201-2207 ◽  
Author(s):  
Eric Deflandre ◽  
Simon Delande ◽  
Jerome Cauvain ◽  
Pierre Geradon ◽  
Anne-Francoise Donneau ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Pulse Pressure ◽  
Open Chest ◽  
Preliminary Study

scholarly journals Surveillance and control of M. chimaera infections in the Tuscany Region, Italy

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
B Casini ◽  
B Tuvo ◽  
M Totaro ◽  
A Baggiani ◽  
G Privitera
Keyword(s):  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Water Sample ◽  
Case Finding ◽  
Microbial Count ◽  
Clinical Specimens ◽  
Open Chest ◽  
Microbiological Parameters ◽  
History Of ◽  
And Control

Abstract Background Disseminated M. chimaera infections among patients who underwent open-chest surgery with cardiopulmonary bypass have been associated with the contamination of heater-cooler devices (HCDs). The Tuscany region in the Decree 3822/2019 issued recommendations for the surveillance and control of M. chimaera infections. Methods In three Tuscan cardiac surgery centers, the case finding was carried out through evaluation and testing of patients with a history of HCD exposure (past 6 years) was performed. Water and aerosol samples were analyzed from each HCDs to determine the microbiological parameters required by the Directive 98/83/CE and to assess the presence of non-tuberculous mycobacteria (NTMs), according to the regional protocol. Results M. chimaera infection was not found in any patient and all clinical specimens tested negative. 22 HCDs were sampled (n.12 LivaNova, n.1 Terumo and n.9 Maquet) for a total of 114 samples (45, 8, 2 and 59 respectively). All the microbiological parameters were compliant, excepted for total microbial count at 36 °C that exceeded 100 CFU/ml in 50% (57/114) of samples and for the presence of P.aeruginosa in 10% (12/114). NTMs were detected in 16% (18/114) of HCDs: M. chimaera was identified in 11% (13/114) of samples and in 4% (5/114) M. gordonae. All aerosol samples were negative for NTMs, but in the HCDs Maquet, B.cereus were detected in 7% (4/59) of the samples, K.oxytoca in 2% (1/59), B.ursincola in 2% (1/59) and S. paucimobilis in 3% (2/59). Only S. paucimobilis was isolated also in the same HCD water sample. Conclusions The implementation of maintenance and disinfection procedures of HCDs was able to reduce the risk of contamination and aerosolization by NTMs but not of other microorganisms. Key messages Further strategies should be put in place for the cases finding. Moreover, reliable decontamination and identification of agents that can disrupt biofilms and increase chlorine susceptibility of mycobacteria are required.

The Effect of Curvature and Torsion on the Temperature Distribution in a Helix

1985 ◽  
Vol 52 (3) ◽  
pp. 529-532 ◽  
Author(s):  
D. D. Sayers ◽  
M. C. Potter
Keyword(s):  
Differential Equation ◽  
Finite Element Method ◽  
Partial Differential Equation ◽  
Temperature Distribution ◽  
Strong Dependence ◽  
Maximum Temperature ◽  
Nonuniform Heating ◽  
The Finite Element Method ◽  
Curvature Parameter ◽  
Curvature And Torsion

Traditional analysis treats the helix as a straight wire with the effects of nonuniform heating, torsion, and large curvature ignored. Using a helical coordinate system the governing partial differential equation including these effects is derived. The equation is then solved numerically using the finite element method. The results indicate a strong dependence of the temperature on the torsion parameter when the curvature parameter is significant. As the curvature parameter increases, the temperature distribution becomes skew-symmetric and the maximum temperature in the helix increases. Nonuniform heating influences the temperature distribution independent of the curvature and torsion.

Computer Modelling of Temperature Distribution in Brake Drums for Fade Assessment

1988 ◽  
Vol 202 (4) ◽  
pp. 257-264 ◽  
Author(s):  
V T V S Ramachandra Rao ◽  
H Ramasubramanian ◽  
K N Seetharamu
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Temperature Distribution ◽  
Present Model ◽  
Computer Modelling ◽  
Convective Heat Transfer Coefficient ◽  
The Finite Element Method ◽  
Data Logging ◽  
Brake Drum ◽  
Predicted Values

Simulation of the temperature distribution in a brake drum of a commercial truck is carried out using the finite element method. Verification of the predicted values is done using an inertia dynamometer with a data logging system. The effect of variable convective heat-transfer coefficient and the effect of contact area are also studied. From the investigation it is concluded that the present model can be used for the simulation of temperature distribution in rigid brake drums during a fade test.

Assessing volume responsiveness during open chest conditions in cardiac surgery patients

2004 ◽  
Vol 21 (Supplement 33) ◽  
pp. 2
Author(s):  
D. A. Reuter ◽  
T. Goresch ◽  
M. S.G. Goepfert ◽  
M. Schmoeckel ◽  
E. Kilger ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Volume Responsiveness ◽  
Open Chest

Application of the Finite Element Method (FEM) through GFAS Software to the study of a tunnel

2021 ◽  
Vol 4 (2) ◽  
pp. 001
Author(s):  
Maurizio Ponte ◽  
◽  
Filippo Catanzariti ◽  
Gloria Campilongo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computational Simulation ◽  
Theoretical Method ◽  
The Finite Element Method ◽  
Tunnel Excavation ◽  
Analysis System ◽  
Quality Of Products ◽  
Element Method

Computational simulation is widely used in companies to perform analysis and improve the quality of products and projects. Most of these analyses are carried out using software that uses the Finite Element Method, which allows to obtain answers to numerous engineering problems. In this study, two examples of application to the study of tunnels of the Finite Element Method using the Geostru Software "GFAS - Geotechnical F.E.M. Analysis System" are proposed. The case of a tunnel excavated inside a granite rock massif was analyzed, first determining the state of stresses in the cavity contour through a theoretical method and comparing these results with those obtained in the software. Then, by means of finite element modeling, the settlements induced by the excavation were determined. Finally, the problem of tunnel excavation in a viscoplastic rock mass is presented and the authors propose a comparison of the analytical and numerical method.

scholarly journals Thermal distribution analysis of inner defects in TSV

2018 ◽  
Vol 38 ◽  
pp. 04026
Author(s):  
Chuan Kai Jiang ◽  
Lei Nie ◽  
Wen Jia ◽  
Yu Ning Zhong
Keyword(s):  
Thermal Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Temperature Variation ◽  
Finite Element Models ◽  
Distribution Analysis ◽  
Internal Defects ◽  
External Temperature ◽  
Thermal Distribution ◽  
Distinct Temperature

In order to uncover the external manifestations of TSV internal defects, the finite element models of typical internal defects, which were filling missing, axial cavity and end cavity, were established. The thermal analysis was carried out using thermoelectric coupling method. The temperature distribution of TSV with and without defects were obtained. And the temperature variation profiles on the defined paths of TSV layer were also analyzed. The analysis indicated that all the defective TSV showed distinct temperature distribution with the defect-free TSV. Among three typical defects, TSV with filling missing showed the most obvious difference on the temperature distribution and path variation. TSV with end cavity has relatively weak affect and the slightest defect was TSV with axial cavity. Therefore, it could be seen that the external temperature difference caused by the internal defects of TSV could provide effective information for the identification and detection in TSV with internal defects.

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