Magnetic resonance electrical properties tomography for small anomalies using boundary conditions: A simulation study

2017 ◽  
Vol 44 (9) ◽  
pp. 4773-4785 ◽  
Author(s):  
Joonsung Lee ◽  
Narae Choi ◽  
Jin Keun Seo ◽  
Dong-Hyun Kim
Keyword(s):  
Magnetic Resonance ◽  
Electrical Properties ◽  
Boundary Conditions ◽  
Simulation Study

scholarly journals Effects of Loading and Boundary Conditions on the Performance of Ultrasound Compressional Viscoelastography: A Computational Simulation Study to Guide Experimental Design

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2590
Author(s):  
Che-Yu Lin ◽  
Ke-Vin Chang
Keyword(s):  
Boundary Conditions ◽  
Simulation Study ◽  
Viscoelastic Properties ◽  
Measurement Accuracy ◽  
Computational Simulation ◽  
Vertical Direction ◽  
Fixation Method ◽  
Element Analysis ◽  
Sample Container

Most biomaterials and tissues are viscoelastic; thus, evaluating viscoelastic properties is important for numerous biomedical applications. Compressional viscoelastography is an ultrasound imaging technique used for measuring the viscoelastic properties of biomaterials and tissues. It analyzes the creep behavior of a material under an external mechanical compression. The aim of this study is to use finite element analysis to investigate how loading conditions (the distribution of the applied compressional pressure on the surface of the sample) and boundary conditions (the fixation method used to stabilize the sample) can affect the measurement accuracy of compressional viscoelastography. The results show that loading and boundary conditions in computational simulations of compressional viscoelastography can severely affect the measurement accuracy of the viscoelastic properties of materials. The measurement can only be accurate if the compressional pressure is exerted on the entire top surface of the sample, as well as if the bottom of the sample is fixed only along the vertical direction. These findings imply that, in an experimental validation study, the phantom design should take into account that the surface area of the pressure plate must be equal to or larger than that of the top surface of the sample, and the sample should be placed directly on the testing platform without any fixation (such as a sample container). The findings indicate that when applying compressional viscoelastography to real tissues in vivo, consideration should be given to the representative loading and boundary conditions. The findings of the present simulation study will provide a reference for experimental phantom designs regarding loading and boundary conditions, as well as guidance towards validating the experimental results of compressional viscoelastography.

Diffusion tensor magnetic resonance imaging

2018 ◽  
pp. 624-628
Author(s):  
David Sosnovik
Keyword(s):  
Magnetic Resonance Imaging ◽  
Heart Failure ◽  
Magnetic Resonance ◽  
Electrical Properties ◽  
Diffusion Tensor ◽  
Resonance Imaging ◽  
Mechanical And Electrical Properties ◽  
Clinical Scenarios ◽  
Translational Studies ◽  
Whole Heart

The microstructure of the heart has a major impact on its mechanical and electrical properties. Diffusion tensor magnetic resonance imaging (DTI) exploits the anisotropic restriction of water diffusion in the myocardium to resolve its microstructure. Recent advances in the field have included the development of acceleration-compensated diffusion-encoded sequences, the investigation of sheet dynamics, and the development of highly accelerated techniques to enable whole heart coverage. Translational studies have demonstrated the utility of DTI in heart failure and other cardiomyopathies. While DTI of the heart remains investigational, ongoing advances in the field will soon allow the technique to be performed reliably and quickly in appropriate clinical scenarios.

scholarly journals Impact of Boundary Conditions on the Performance Enhancement of Advanced Control Strategies for a Residential Building with a Heat Pump and PV System with Energy Storage

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1413
Author(s):  
Emmanouil Psimopoulos ◽  
Fatemeh Johari ◽  
Chris Bales ◽  
Joakim Widén
Keyword(s):  
Energy Storage ◽  
Boundary Conditions ◽  
Heat Pump ◽  
Simulation Study ◽  
Control Strategies ◽  
Thermal Storage ◽  
Hot Water ◽  
Final Energy ◽  
Advanced Control ◽  
The Impact

Operational control strategies for the heating system of a single-family house with exhaust air heat pump and photovoltaic system and “smart” utilization of energy storage have been developed and evaluated in a simulation study. The main aim and novelty of this study is to evaluate the impact on the benefit of these advanced control strategies in terms of performance (energy use and economic) for a wide range of boundary conditions (country/climate, occupancy and appliance loads). Short-term weather data and historic price data for the same year as well as stochastic occupancy profiles that include the domestic hot water load are used as boundary for a parametric simulation study for the system modeled in detail in TRNSYS 17. Results show that the control using a forecast of dynamic electricity price leads to greater final energy savings than those due to the control using thermal storage for excess PV production in all of the examined locations except Sweden. The impact on self-consumption using thermal storage of heat produced by the heat pump using excess PV production is found to decrease linearly with increasing household electricity for all locations. A reduction in final energy of up to 842 kWh year−1 can be achieved just by the use of these algorithms. The net energy cost for the end-user follows the same trend as for final energy and can result in cost savings up to 175 € year−1 in Germany and Spain due to the use of the advanced control.

Divergence-Based Magnetic Resonance Electrical Properties Tomography

2021 ◽  
Vol 68 (1) ◽  
pp. 192-203 ◽  
Author(s):  
Chunyi Liu ◽  
Lei Guo ◽  
Mingyan Li ◽  
Haiwei Chen ◽  
Jin Jin ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Electrical Properties
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