COMPUTATIONAL SIMULATION OF HYGROTHERMAL PERFORMANCE OF PLASTERS WITH ENHANCED MOISTURE ACCUMULATION CAPABILITY

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Jan Kočí ◽  
Jan Fořt ◽  
Jiří Maděra
Keyword(s):  
Temperature Distribution ◽  
Input Parameter ◽  
Computational Simulation ◽  
Reference Sample ◽  
Building Envelope ◽  
Computational Simulations ◽  
Surface Layers ◽  
Hygrothermal Performance ◽  
Thermal Buffering ◽  
Hygric Properties

Series of computational simulations are performed within this paper in order to investigate the hygrothermal response of several plasters with enhanced accumulation properties. The newly developed plasters are modified from the reference sample by adding various amounts of super absorbent polymers. Then, the basic physical, thermal and hygric properties are determined in the laboratory conditions and subsequently used as an input parameter in the computational simulations. The simulation output showed that even a thin layer of exterior and interior plaster may significantly affect the hygrothermal performance of the entire building envelope due to increased moisture and thermal buffering of the surface layers. Differences in relative humidity distribution across the studied construction were generally up to 10 % between individual plasters, differences of temperature distribution were mostly negligible, except for the cases when sudden changes of surface temperature were observed. Then, the thermal buffering was evident and the differences of temperature in surface layers were up to 4°C among studied plasters.

Effect of Zeolite Admixture on Freeze/Thaw Resistance of Concrete Exposed to the Dynamic Climatic Conditions

2014 ◽  
Vol 982 ◽  
pp. 27-31 ◽  
Author(s):  
Václav Kočí ◽  
Miloš Jerman ◽  
Jiří Maděra ◽  
Robert Černý
Keyword(s):  
Service Life ◽  
Computational Simulation ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Point Of View ◽  
Freeze Thaw ◽  
Hygrothermal Behavior ◽  
Hygrothermal Performance ◽  
Concrete Building ◽  
Positive Effect

This paper aims at computational simulation of effect of zeolite admixture on service life of concrete building envelope from point of view of freeze/thaw resistance. Hygrothermal behavior of two types of concrete is studied in this paper: reference concrete without any admixtures and zeolite concrete with 40 % zeolite as cement replacement. The computations are performed using computer simulation tool HEMOT, which processes the input parameters using finite element method. The simulation is assumed under dynamic climatic conditions of Prague. As the results of the computational simulations showed, assuming analyzed amount of zeolite, any positive effect of on freeze/thaw resistance was not found related to unprotected building envelope. However, the results indicated, hygrothermal performance of zeolite concrete can be very considerate to applied external layers and thus extend their service life.

Hygrothermal performance of various Typha–clay composite

2018 ◽  
Vol 42 (3) ◽  
pp. 316-335 ◽  
Author(s):  
Ibrahim Niang ◽  
Chadi Maalouf ◽  
Tala Moussa ◽  
Christophe Bliard ◽  
Etienne Samin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Optimal Composition ◽  
Volume Weight ◽  
Hygrothermal Behavior ◽  
Three Samples ◽  
Hygrothermal Performance ◽  
Absolute Density ◽  
Typha Australis ◽  
Hygric Properties ◽  
Made In

This article deals with the influence of both morphology and amount of Typha on hygrothermal behavior of a Typha–clay composite for building application. An agromaterial containing the fiber mix of Typha Australis and clay was made in three samples: three fiber mixtures were prepared with different amounts Typha and cut type (transversal or longitudinal). The physical properties of these materials were studied in terms of porosity, apparent and absolute density, thermal conductivity, and hygric properties. Results show a real impact of the Typha fraction type and its volume content on hygrothermal properties of the studied material due to the porosity. The transversal fraction of Typha (80% in volume weight) seems to be the optimal composition for a better hygrothermal behavior.

Computational Investigation and Histopathological Validation of Interaction Between Stent Graft and Aorta in Retrograde Type A Dissection After TEVAR in Canine Models

2021 ◽  
pp. 152660282110385
Author(s):  
Tao Ma ◽  
Min Zhou ◽  
Zhuang Yuan Meng ◽  
Shengzhang Wang ◽  
Zhi Hui Dong ◽  
...  
Keyword(s):  
Aortic Wall ◽  
Computational Simulation ◽  
Elastic Fiber ◽  
False Lumen ◽  
Type A ◽  
Computational Simulations ◽  
Landing Zone ◽  
Custom Made ◽  
Medial Necrosis ◽  
Type A Dissection

Purpose: Retrograde type A dissection (RTAD) after thoracic endovascular aortic repair (TEVAR) has been a major drawback of endovascular treatment. To our knowledge, no studies have simulated and validated aortic injuries caused by stent grafts (SGs) in animal models. Therefore, the aim of this study was to evaluate and quantify the SG–aorta interaction through computational simulations and to investigate the underlying mechanism through histopathological examinations. Methods: Two custom-made Fabulous® (DiNovA Meditech, Hang Zhou, China) SGs were implanted in 2 canine aortas with a 5-mm difference in the distance in landing locations. The aortic geometries were extracted from RTAD and non-RTAD cases. A computational SG model was assembled based on the implanted SG using the software Pro-ENGINEER Wildfire 5.0 (PTC Corporation, Needham, Mass). TEVAR simulations were performed 7 times for each canine model using Abaqus software (Providence, RI, USA), and the maximum aortic stress (MAS) was calculated and compared among the groups. Three months after SG implantation, the canine aortas were harvested, and were examined using hematoxylin and eosin staining and Elastica Van Gieson (EVG) staining to evaluate histopathological changes. Results: In the computational models for both canines, MAS was observed at the proximal bare stent (PBS) at aortic greater curve. The PBS generated higher stress toward the aortic wall than other SG parts did. Moreover, the MAS was significantly higher in canine No.1 than in canine No.2 (0.415±0.210 versus 0.200±0.160 MPa) (p<0.01). Notably, in canine No.1, an RTAD developed at the MAS segment, and histopathological examinations of the segment showed an intimal flap, a false lumen, elastin changes, and medial necrosis. RTAD was not observed in canine No.2. In both SG-covered aortas, medial necrosis, elastic fiber stretching, and inflammatory infiltration were seen. Conclusion: The characteristic MAS distribution remained at the location where the apex of the PBS interacted with the aortic wall at greater curve. RTAD histopathological examinations showed intimal damage and medial necrosis at the proximal landing zone, at the same MAS location in computational simulations. The in vivo results were consistent with the computational simulations, suggesting the MAS at greater curve may cause RTAD, and the potential application of computational simulation in the mechanism study of RTAD.

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 Optimizing the computational simulations of air-flammable gas explosions using HPC and Ansys software

2020 ◽  
Vol 305 ◽  
pp. 00052
Author(s):  
Laurenţiu Munteanu ◽  
Marius Cornel Şuvar ◽  
Ligia Ioana Tuhuţ
Keyword(s):  
Fluid Dynamics ◽  
High Performance ◽  
Computational Simulation ◽  
Scientific Work ◽  
Phase Method ◽  
Separate Analysis ◽  
Computational Simulations ◽  
Ansys Fluent ◽  
Gas Explosions ◽  
Future Extension

The purpose of this scientific work is to improve computer simulations of flammable air-gas explosions with HPC systems. Computational Fluid Dynamics (CFD) is increasingly used for obtaining variable values of fluid flow areas, respectively for the manner in which fluids react with limited surfaces. For a separate analysis of liquids and gases is used CFD, and for more realistic results is used the multi-phase method performed by ANSYS Fluent, which improves the calculation scalability and power. For increasing the processing speed for complex analyses, with multiple geometries and fine meshes, ANSYS provides the user HPC (High Performance Computing) tools applicable for structural, thermal, electromagnetic, fluid dynamics and explicit dynamics solvers. HPC configuration is characterized by a good scalability, having the capacity for future extension of cores or processors. For decreasing the computational simulation time for explosions, the proposed solution consists in running complex simulations on the servers of a HPC cluster. In this way is provided the possibility for a parallel or distributed running on one or several calculation systems. Using HPC along ANSYS applications may be activated by GPU acceleration, while other applications are limited to processing using CPUs. INSEMEX develops technical investigations of explosions and fires occurred in the industrial or civilian field, in compliance with Government Decision 1461/2006, based on the verification of scenarios using virtual computational simulations.

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