Journal articles on the topic 'Multiphysic imager'
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Zolotukhin P. A., Il'ichev E. A., Petrukhin G. N., Popov A. V., Rychkov G. S., and Teverovskaya E. G. "Calculation and optimization of the limiting characteristics of a single-channel dual-spectrum image receiver of objects emitting in the ultraviolet range." Technical Physics 92, no. 9 (2022): 1254. http://dx.doi.org/10.21883/tp.2022.09.54691.97-22.
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A single-channel, two-spectral image receiver of objects emitting in UV radiation, made in the image intensifier tube architecture, was proposed and investigated. With the help of the COMSOL Multiphysics software package, search optimal measurements of the potential on the elements of the image receiver (silicon membrane, germanium and diamond photocathode, MCP input and output sensors) were implemented, which provides the possibility of registering and presence of UV objects in relation to the terrain. Keywords: image intensifier tube, diamond photocathode, germanium photocathode, ultraviolet radiation, object imager, photoelectron emission, secondary electron emission.
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Kim, Yoon Young, Jae Chun Ryu, Eunil Kim, Hyoungkee Kim, and Byungseong Ahn. "A Variational Art Algorithm for Image Generation." Leonardo 49, no. 3 (June 2016): 226–31. http://dx.doi.org/10.1162/leon_a_00914.
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The authors propose a variational art algorithm: a virtual system-based optimization algorithm developed for generating images. Observing that the topology optimization method used for multiphysics system design can produce two- or three-dimensional layouts without baselines, the authors propose to expand it beyond engineering applications for generating images. They have devised a virtual physical system—a heat-path system—that “interprets” the optimization-based process of image generation as the simultaneous drawing of multiple strokes in a painting.
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Leslie, Nathaniel, and Janine Mauzeroll. "Simulating Scanning Electrochemical Microscopy Images of Arbitrarily Shaped Reactive Sites without a Site-Specific Model." ECS Meeting Abstracts MA2022-01, no. 46 (July 7, 2022): 1947. http://dx.doi.org/10.1149/ma2022-01461947mtgabs.
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Scanning electrochemical microscopy (SECM) yields two-dimensional electrochemical images when the current at a microelectrode is recorded as it moves above a surface generating redox species. As SECM images are often systematically compared to microstructure features obtained by electron microscopy there is a clear need to find ways to integrate electron microscopy images into SECM image simulations. Recently, finite element method simulations of sites where electrochemical reactions take place is employed to evaluate reactive feature size.[1] Current models move the microelectrode or the reacting surface, continuously changing the geometry of the simulation and thus requiring re-meshing, which increases the computation time. We present a modeling approach by which SECM images of arbitrarily-shaped reactive sites can be simulated using a grid of pixels that can be turned ‘on’ and ‘off’ using COMSOL® multiphysics. Specifically, COMSOL®’s Java API is used to change the selection of pixels that are turned ‘on’ to simulate the movement of the electrode without changing the geometry of the simulation. The mesh can be re-used for each data-point in the image, dramatically reducing the time needed to simulate SECM images. This work also presents a mostly automated workflow for using an electron microscopy image of a reactive site to determine which pixels should be turned ‘on’ and fitting the kinetics at these pixels by simulating their SECM image. [1] L. I. Stephens, N. A. Payne, S. A. Skaanvik, D. Polcari, M. Geissler, J. Mauzeroll, Evaluating the Use of Edge Detection in Extracting Feature Size from Scanning Electrochemical Microscopy Images. Analytical Chemistry 2019, 91, 3944-3950.
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Luo, Yongzhen, Guocong Lin, Xidong Ding, and Tao Su. "The detection of buried nanopillar based on electrostatic force microscopy simulation." AIP Advances 12, no. 6 (June 1, 2022): 065211. http://dx.doi.org/10.1063/5.0088843.
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Based on electrostatic force microscopy (EFM), the image of nano-objects buried below the surface was numerically simulated by using COMSOL Multiphysics® software. The shape and the approximate size of the buried pillar could be obtained from the simulated EFM images. It was demonstrated that the detection of the buried nanopillar based on EFM was feasible. When the image data measured by EFM were used as the input data for comparison with the simulated data, the three unknowns (relative dielectric constant ε r, p, buried depth d, and side length l) of the buried pillar could be obtained. In this paper, the simulated EFM image data were used as the input data. The accurate values of ε r, p, d, and l of the buried nanopillar could be obtained by comparing the input data with the data simulated with other known parameters. The results showed that EFM was a good candidate as a kind of three dimensional nanoscale tomographic technique. It could map the physical properties of buried nanomaterials, which are relevant to modern integrated circuits.
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Yang, Dan, Jiahua Liu, Yuchen Wang, Bin Xu, and Xu Wang. "Application of a Generative Adversarial Network in Image Reconstruction of Magnetic Induction Tomography." Sensors 21, no. 11 (June 3, 2021): 3869. http://dx.doi.org/10.3390/s21113869.
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Image reconstruction of Magnetic induction tomography (MIT) is an ill-posed problem. The non-linear characteristics lead many difficulties to its solution. In this paper, a method based on a Generative Adversarial Network (GAN) is presented to tackle these barriers. Firstly, the principle of MIT is analyzed. Then the process for finding the global optimum of conductivity distribution is described as a training process, and the GAN model is proposed. Finally, the image was reconstructed by a part of the model (the generator). All datasets are obtained from an eight-channel MIT model by COMSOL Multiphysics software. The voltage measurement samples are used as input to the trained network, and its output is an estimate for image reconstruction of the internal conductivity distribution. The results based on the proposed model and the traditional algorithms were compared, which have shown that average root mean squared error of reconstruction results obtained by the proposed method is 0.090, and the average correlation coefficient with original images is 0.940, better than corresponding indicators of BPNN and Tikhonov regularization algorithms. Accordingly, the GAN algorithm was able to fit the non-linear relationship between input and output, and visual images also show that it solved the usual problems of artifact in traditional algorithm and hot pixels in L2 regularization, which is of great significance for other ill-posed or non-linear problems.
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Grevcev A. S., Zolotukhin P. A., Il'ichev E. A., Petruhin G. N., Popov A. V., and Rychkov G. S. "The thermal image receiver realized in the electron-optical converter architecture." Technical Physics 92, no. 4 (2022): 419. http://dx.doi.org/10.21883/tp.2022.04.53597.270-21.
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An innovative design is considered, and the results of analysis and calculations of the characteristics of a thermal image receiver (3-15 microns), made in the electron-optical converter architecture, are presented. For the sensor-converting pyroelectric unit of the electron-optical converter, the spatial dependences of the electric field strengths and the values of the electric potentials on the spontaneous polarization of the film substance are calculated. Estimates are obtained and the characteristics of thermal-field-induced polarization of various pyroelectric films are discussed. The temperature dependences of the polarization characteristics of a number of pyroelectric films are calculated using the finite element method in the COMSOL Multiphysics software package. Possible contributions of the piezoelectric effect to the picture of the distribution of electric potentials from the thermal polarization of pyroelectric films are taken into account. Estimates are obtained for the limiting values of the main instrument characteristics of the electron-optical converter. Keywords: the electron-optical converter, spontaneous polarization, pyroelectric, bolometric thermal imagers, pyroelectric thermal imagers.
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Yang, Liu, Chun Guang Xu, Xiang Hui Guo, Xin Liang Li, Qi Lin, Ye Huang, and Hao Yu Sun. "Multi-Objects Ultrasonic Tomography by Immersion Circular Array." Advanced Materials Research 1006-1007 (August 2014): 879–83. http://dx.doi.org/10.4028/www.scientific.net/amr.1006-1007.879.
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The typical application of ultrasonic tomography is the determination of process parameters like component flow rates and material fractions in industrial environment. Another promising application is non-invasive health monitoring in medical care. Both acoustic attenuation and acoustic impedance inhomogeneity are the main physical quantities that are used to reconstruct the image. When transmission ultrasonic waves are shadowed by hard tissue because of severe attenuation, the reflection mode can be an effective supplement. This paper provides multi-objects reconstruction images by reflection ultrasonic tomography, demonstrating the multi-objects imaging capability of an immersion circular array system. The circular array consists of 36 ultrasonic transducers with 0.5MHz frequency which are ring arranged and embedded in the container wall to serve as both transmitter and receiver. Each time one transducer is fired and in the meantime other transducers are enabled to receive signals. Ultrasonic transmitting, propagating and receiving of the circular array system are simulated by COMSOL Multiphysics® software, after that a series of image reconstructions of the objects with different numbers are obtained through ellipse algorithm.
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Sukor, Nur Syafiqah Amirah Ab, Fatinah Mohd Rahalim, Juliza Jamaludin, and Normaliza Ab Malik. "A Conceptual Model of Dual-Mode Tomography Technique for Dental Diagnostics: Ultrasound and Light Propagation Analysis." Journal of Physics: Conference Series 2641, no. 1 (November 1, 2023): 012008. http://dx.doi.org/10.1088/1742-6596/2641/1/012008.
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Abstract Many advanced imaging modalities, such as magnetic resonance imaging (MRI), X-ray Computed Tomography, Positron Emission Tomography (PET), Ultrasound, Single Photon Emission Computed Tomography (SPECT), and the most recent, Optical Coherence Tomography (OCT), have been developed for identifying dental tissues images and detecting changes in early carious lesions. Some modalities use high doses of radiation and energy to obtain more information, which may be harmful to patient’s health. Most early commercial OCTs had drawbacks such as its bulky size and limited image resolution. In order to overcome these concerns, this paper presents a dual-mode tomography technique that combines OCT and ultrasound method using the COMSOL Multiphysics. The application of an ultrasound device helps overcome the limitation of OCT in detecting the penetration depth of a caries lesion. Several simulations were performed to analyse the light and ultrasonic propagated waves with different diameters of carious lesions. In response to this goal, the combination data of OCT and ultrasound provide a 3D image which offers the best approach for displaying and examining changes in the oral cavity.
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Razali, Nazirah Mohd, Muhammad Quisar Lokman, Siti Nur Fatin Zuikafly, Fauzan Ahmad, and Hafizal Yahaya. "Simulation of Self-Image Interference in Single Mode-No-Core-Single Mode Fiber with COMSOL Multiphysics®." Journal of Physics: Conference Series 2411, no. 1 (December 1, 2022): 012019. http://dx.doi.org/10.1088/1742-6596/2411/1/012019.
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Abstract Self-image interference in a single mode-no-core-single mode fiber plays an important role especially for length optimization before acting as a sensor. The interference can be observed through optical simulation software. Past literature has successfully demonstrated the interference via COMSOL Multiphysics®, but the simulation was not restricted to the use of important domains and settings such as perfectly matched layer and surrounding domain causing imprecise simulation results. This paper proposes a simulation of self-image interference in a single mode-no-core-single mode fiber by using the wave-optics module in COMSOL Multiphysics® software. The beam propagation method is used to observe the self-image interference for different self-image indexes ranging from one to four indexes while the self-image length is obtained from the theoretical calculation before a simulation is carried out. The results show that accurate results can be obtained with restricted simulation settings. The number of the self-image index and self-image length produced by the simulation are similar to the calculation. The self-image point is located exactly at the calculated length with a four-decimal point 0.0000 difference, thus overcoming the limitation of the simulated previous work. In the future, the simulation settings and results can be used for reference to simulate the single mode- no-core-single mode fiber structure.
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Chin, Lixin, Andrea Curatolo, Brendan F. Kennedy, Barry J. Doyle, Peter R. T. Munro, Robert A. McLaughlin, and David D. Sampson. "Analysis of image formation in optical coherence elastography using a multiphysics approach." Biomedical Optics Express 5, no. 9 (August 1, 2014): 2913. http://dx.doi.org/10.1364/boe.5.002913.
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Lad, Yash, Avesh Jangam, Hayden Carlton, Ma’Moun Abu-Ayyad, Constantinos Hadjipanayis, Robert Ivkov, Brad E. Zacharia, and Anilchandra Attaluri. "Development of a Treatment Planning Framework for Laser Interstitial Thermal Therapy (LITT)." Cancers 15, no. 18 (September 14, 2023): 4554. http://dx.doi.org/10.3390/cancers15184554.
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Purpose: Develop a treatment planning framework for neurosurgeons treating high-grade gliomas with LITT to minimize the learning curve and improve tumor thermal dose coverage. Methods: Deidentified patient images were segmented using the image segmentation software Materialize MIMICS©. Segmented images were imported into the commercial finite element analysis (FEA) software COMSOL Multiphysics© to perform bioheat transfer simulations. The laser probe was modeled as a cylindrical object with radius 0.7 mm and length 100 mm, with a constant beam diameter. A modeled laser probe was placed in the tumor in accordance with patient specific patient magnetic resonance temperature imaging (MRTi) data. The laser energy was modeled as a deposited beam heat source in the FEA software. Penne’s bioheat equation was used to model heat transfer in brain tissue. The cerebrospinal fluid (CSF) was modeled as a solid with convectively enhanced conductivity to capture heat sink effects. In this study, thermal damage-dependent blood perfusion was assessed. Pulsed laser heating was modeled based on patient treatment logs. The stationary heat source and pullback heat source techniques were modeled to compare the calculated tissue damage. The developed bioheat transfer model was compared to MRTi data obtained from a laser log during LITT procedures. The application builder module in COMSOL Multiphysics© was utilized to create a Graphical User Interface (GUI) for the treatment planning framework. Results: Simulations predicted increased thermal damage (10–15%) in the tumor for the pullback heat source approach compared with the stationary heat source. The model-predicted temperature profiles followed trends similar to those of the MRTi data. Simulations predicted partial tissue ablation in tumors proximal to the CSF ventricle. Conclusion: A mobile platform-based GUI for bioheat transfer simulation was developed to aid neurosurgeons in conveniently varying the simulation parameters according to a patient-specific treatment plan. The convective effects of the CSF should be modeled with heat sink effects for accurate LITT treatment planning.
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Geary, Andrew. "Seismic Soundoff." Leading Edge 40, no. 2 (February 2021): 160. http://dx.doi.org/10.1190/tle40020160.1.
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Lucy MacGregor highlights her 2021 Distinguished Lecture, “Multiphysics analysis: Extracting the most from diverse data sets.” She discusses how combining data sets can compensate for weaknesses in each, how utilizing gravity data improves the seismic image, the biggest obstacle in utilizing data sets, and more. Hear the full episode at https://seg.org/podcast/post/11276 .
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Liu, Jian Jun, and Wan Lin Chen. "Generational Technology of Computational Grid in Porous Media Based on Digital Image." Advanced Materials Research 524-527 (May 2012): 1429–34. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.1429.
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Based on digital imaging processing technology, a generational method of computational grid of porous media is developed for numerical simulation. Transformation of original microscopical image from grayscale into binary one and vector-graph are used for reconstructing a geometric model of porous media. Computational grid of porous media geometry model by COMSOL Multiphysics software can provide an effective way for the latter finite element analysis of porous media.
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Tu, Xiaolei, and Michael S. Zhdanov. "Joint Gramian inversion of geophysical data with different resolution capabilities: case study in Yellowstone." Geophysical Journal International 226, no. 2 (April 5, 2021): 1058–85. http://dx.doi.org/10.1093/gji/ggab131.
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SUMMARY Joint inversion of multiphysics data is a practical approach to the integration of geophysical data, which produces models of reduced uncertainty and improved resolution. The development of effective methods of joint inversion requires considering different resolutions of different geophysical methods. This paper presents a new framework of joint inversion of multiphysics data, which is based on a novel formulation of Gramian constraints and mitigates the difference in resolution capabilities of different geophysical methods. Our approach enforces structural similarity between different model parameters through minimizing a structural Gramian term, and it also balances the different resolutions of geophysical methods using a multiscale resampling strategy. The effectiveness of the proposed method is demonstrated by synthetic model study of joint inversion of the P-wave traveltime and gravity data. We apply a novel method based on Gramian constraints and multiscale resampling to jointly invert the gravity and seismic data collected in Yellowstone national Park to image the crustal magmatic system of the Yellowstone. Our results helped to produce a consistent image of the crustal magmatic system of the Yellowstone expressed both in low-density and low-velocity anomaly just beneath the Yellowstone caldera.
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Ciou, Yong Jie, Yean Ren Hwang, and Jing Chie Lin. "Theoretical Modeling and Fabrication of Two-Dimensional Microstructures by Using Micro-Anode-Guided Electroplating with Real-Time Image Processing." Key Engineering Materials 656-657 (July 2015): 604–14. http://dx.doi.org/10.4028/www.scientific.net/kem.656-657.604.
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the purpose of this research was to develop a new micro-anode-guided electroplating (MAGE) system equipped by an image-guided positioning controller, to fabricate two-dimensional microstructures. From real-time image, the relative positions of the micro-anode and the microstructures tip can be located and maintained. When the relative position is adjusted, the deposition direction of the microstructures can be controllable and microstructures with different geometries can be fabricated. Moreover, the results of experiment can be explained by the distribution of electro field strength simulated by Comsol Multiphysics 4.2.
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Aleksanyan, Grayr, Nikolay Gorbatenko, Maria Konko, and Cuong Nguyen Manh. "Computer model for acquisition, processing, analysis and visualization of measurement data by electrical impedance tomography." E3S Web of Conferences 389 (2023): 07009. http://dx.doi.org/10.1051/e3sconf/202338907009.
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In this article, a computer model for the collection, processing, analysis and visualization of measurement data by the method of electrical impedance tomography has been developed. The essence of the work performed is to build a computer model of the phantom, electrodes, conductive medium and inhomogeneities in the COMSOL Multiphysics environment to study the conductivity of objects in order to reduce the error in determining the size of the inhomogeneity in the reconstructed image. The study is performed by placing an inhomogeneity phantom in the conductive region. Based on the data obtained, a matrix of potential differences is constructed using the “near neighbor” algorithm. On its basis, in the GNU Octave environment, using the EIDORS package, a reconstruction of the conducted studies is obtained. With the help of the developed software that implements the method and algorithm for refining the boundaries, filtered images of reconstructions of the results of the studies are obtained. The use of this algorithm makes it possible to reduce the measurement error by a factor of 1.44.
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Ye, Zhijun, Yi Chen, Chao Yang, Di Wu, Jia Wang, Liang Hu, Li Duan, and Qi Kang. "The Mechanism of Droplet Thermocapillary Migration Coupled with Multi-Physical Fields." Symmetry 15, no. 11 (November 15, 2023): 2069. http://dx.doi.org/10.3390/sym15112069.
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In this paper, the coupling effect of multiphysical fields of droplet migration is deeply studied by constructing a physical model of droplet migration with multiphysical fields. Digital holographic interferometry and particle image velocimetry are used to simultaneously measure the temperature and velocity fields of the mother liquor in the process of droplet migration for the first time. Due to the advancements of measuring, the zero-velocity region is also in the region where the thermal wake appears, four vortexes appear in the droplet migration and the off-axis behavior of double-droplet migration is found. The aim of this work is to analyze the coupling relationship of multiphysical fields, so as to reveal the physical laws of thermocapillary migration of single droplet and multiple droplets with the same phase and heterophase and to study the driving mechanism of the thermocapillary force and the flow of the mother liquor.
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Sfarra, Stefano, Clemente Ibarra-Castanedo, Carlo Santulli, Domenica Paoletti, and Xavier Maldague. "Monitoring of jute/hemp fiber hybrid laminates by nondestructive testing techniques." Science and Engineering of Composite Materials 23, no. 3 (May 1, 2016): 283–300. http://dx.doi.org/10.1515/secm-2013-0138.
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AbstractDamage following static indentation of jute/hemp (50 wt.% total fiber content) hybrid laminates was detected by a number of nondestructive testing (NDT) techniques, in particular, near (NIR) and short-wave (SWIR) infrared reflectography and transmittography, infrared thermography (IRT), digital speckle photography (DSP), and holographic interferometry (HI), to discover and evaluate real defects in a laminate with a complex structure. A comparative study between thermographic data acquired in the mid- (MWIR) and long-wave infrared (LWIR) spectrum bands, by pulsed (PT) and square pulse (SPT) thermography, is reported and analyzed. A thermal simulation by COMSOL® Multiphysics (COMSOL Inc., Burlington, MA, USA) to validate the heating provided is also added. The robust SOBI (SOBI-RO) algorithm, available into the ICALAB Toolbox (BSI RIKEN ABSP Lab, Hirosawa, Japan) and operating in the MATLAB® (The MathWorks, Inc., Natick, MA, USA) environment, was applied on SPT data with results comparable to the ones acquired by several thermographic techniques. Finally, segmentation operators were applied both to the NIR/SWIR transmittography images and to a characteristic principal component thermography (PCT) image (EOFs) to visualize damage in the area surrounding indentation.
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Shalaby, Noha, Nejib Zemzemi, and Khalil Elkhodary. "Simulating the effect of sodium channel blockage on cardiac electromechanics." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 234, no. 1 (October 18, 2019): 16–27. http://dx.doi.org/10.1177/0954411919882514.
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There is growing interest to better understand drug-induced cardiovascular complications and to predict undesirable side effects at as early a stage in the drug development process as possible. The purpose of this paper is to investigate computationally the influence of sodium ion channel blockage on cardiac electromechanics. To do so, we implement a myofiber orientation dependent passive stress model (Holzapfel-Ogden) in the multiphysics solver Chaste to simulate an imaged physiological model of the human ventricles. A dosage of a sodium channel blocker was then applied and its inhibitory effects on the electrical propagation across ventricles were modeled. We employ the Kerckhoffs active stress model to generate electrically excited contractile behavior of myofibers. Our predictions indicate that a delay in the electrical activation of ventricular tissue caused by the sodium channel blockage translates to a delay in the mechanical biomarkers that were investigated. Moreover, sodium channel blockage was found to increase left ventricular twist. A multiphysics computational framework from the cell level to the organ level was thus used to predict the effect of sodium channel blocking drugs on cardiac electromechanics.
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Ishak*, Nurfarahin, Chua King Lee, and Siti Zarina Mohd Muji. "A Simulation Magnetic Induction Tomography (MIT) for Agarwood using COMSOL Multiphysics." International Journal of Engineering and Advanced Technology 10, no. 3 (February 28, 2021): 67–71. http://dx.doi.org/10.35940/ijeat.c2174.0210321.
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Magnetic induction tomography is an imaging technique used to image electromagnetic properties of an object by using the eddy current effect. (MIT) is a non-destructive method that greatly is used in the agriculture industry. This method provided an opportunity to improve the quality of agricultural products. MIT simulation was used for agarwood existence detection. This paper presented for the simulation system contains 7 channel coils receiver and a channel transmitter which is a sensing detector. This experiment aims to demonstrate the reaction of induced current density and magnetic field at 10 MHz frequency. Then, it also determines the optimal solenoid coil to be used for a better outcome for the magnetic induction system. The simulation result shows that coil diameter, coil length, and coil layer have a crucial role in the great performance of the induced current and magnetic field. The more coil turns, the greater the strength of the permanent magnetic field around the solenoid coil. The result of the simulation is important and needs to be considered to verify the effectiveness of the system for developing the magnetic induction circuit design.
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Vishnuram, Pradeep, Sudhanshu Kumar, Vivek Kumar Singh, Thanikanti Sudhakar Babu, Ramani Kannan, and Khairul Nisak Bt Md Hasan. "Phase Shift-Controlled Dual-Frequency Multi-Load Converter with Independent Power Control for Induction Cooking Applications." Sustainability 14, no. 16 (August 18, 2022): 10278. http://dx.doi.org/10.3390/su141610278.
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Induction heating (IH) applications, assisted with converter topology and their control, have become very attractive in recent years. Independent power control for any induction cooking application with simple converter topology, multi-load handling capacity, and a control technique is still a research hot spot. This paper focuses on developing the dual-frequency converter for delivering power to two loads independently. The switching frequencies of the converter for loads 1 and 2 are selected as 20 and 80 kHz, respectively, and the inverter is operated by multiplexing two switching frequencies. The independent power control is performed using a phase shift control scheme and validated in real-time using a PIC16F877A microcontroller. The prototype of 1 kW is developed and load 1 is operated with 550 W and load 2 is operated with 270 W output power. The independent power control is verified for various values of the control angle (ϕ) and it is noticed that the efficiency is 91% at 0∘ and it is above 80% for other values of ϕ. The thermal model of the proposed system is studied using COMSOL multiphysics software and the experimental image is recorded using a FLIR thermal imager. It is noted that the temperature rise in the load is 78 ∘C and 38.5 ∘C for loads 1 and 2, respectively, at time t = 180 s.
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Solovchuk, Maxim, Tony Wen-Hann Sheu, and Marc Thiriet. "Multiphysics Modeling of Liver Tumor Ablation by High Intensity Focused Ultrasound." Communications in Computational Physics 18, no. 4 (October 2015): 1050–71. http://dx.doi.org/10.4208/cicp.171214.200715s.
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AbstractHigh intensity focused ultrasound is a rapidly developing technology for the ablation of tumors. Liver cancer is one of the most common malignancies worldwide. Since liver has a large number of blood vessels, blood flow cooling can reduce the necrosed volume and may cause regeneration of the tumor to occur. All cancer cells should be ablated without damaging of the critical tissues. Today, treatment planning tools consider liver as a homogeneous organ. This paper is a step towards the development of surgical planning platform for a non-invasive HIFU tumor ablative therapy in a real liver geometry based on CT/MRI image. This task requires coupling of different physical fields: acoustic, thermal and hydrodynamic. These physical fields can influence each other. In this paper we illustrate how a computational model can be used to improve the treatment efficiency. In large blood vessel both convective cooling and acoustic streaming can change the temperature considerably near blood vessel. The whole tumor ablation took only 30 seconds in the considered simulation case, which is very small comparing with the current treatment time of several hours. Through this study we are convinced that high ultrasound power and nonlinear propagation effects with appropriate treatment planning can sufficiently reduce the treatment time.
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Henke, Christian H., Markus H. Krieger, Kurt Strack, and Andrea Zerilli. "Subsalt imaging in northern Germany using multiphysics (magnetotellurics, gravity, and seismic)." Interpretation 8, no. 4 (July 23, 2020): SQ15—SQ24. http://dx.doi.org/10.1190/int-2020-0026.1.
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Imaging subsalt is still a challenging task in oil and gas exploration. We have used magnetotellurics (MT) to improve the integration of seismic and gravity data to image the Wedehof salt dome, located in the Northern German Basin. High-density natural field source broadband MT data were acquired and enhanced the definition of the top and overhanging salt structures in addition to imaging the salt dome root. Salt boundaries show strong resistivity contrasts with the surrounding sediments and thus represent a good target for electromagnetic measurements, especially for top salt and salt flanks imaging. With integrated 3D gravity modeling focusing on the salt dome’s flanks at intermediate depths, an improved model was achieved. The new model provided sound input to a follow-up seismic depth migration that led to an improved imaging of the subsalt target proven by subsequent exploration drilling. The integrated interpretation of MT, gravity, and seismic combines the strengths of the different physics, thus increasing imaging reliability and reducing exploration drilling risks. Using a conservative workflow that included a feasibility study with field noise evaluation and careful acquisition parameter testing prior to survey start, a broadband array data acquisition, and advanced processing, the survey area's severe cultural noise issues could be overcome.
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Ahmad, Irfana Kabir, Muhammad Mukhlisin, and Hassan Basri. "Comparisons of Sensor Position for Electrical Capacitance Volume Tomography (Ecvt)." Modern Applied Science 10, no. 4 (February 2, 2016): 150. http://dx.doi.org/10.5539/mas.v10n4p150.
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<strong><strong></strong></strong><p>Tomography is a technique used to produce true reconstructed images from signal data. This data projection is measured capacitance by numerous sensors located on the surface of the object at different position. Sensitivity matrix with three-dimensional variation, especially in axial (z-axiz) direction are required for imaging a three-dimensional object to differentiate the depth along the sensor length so that the electrical field intensity can be distributed equally all over the three dimension space. In ECVT, when a dielectric material is introduced into the vessel, the variation in the electrical capacitance between all possible combinations of electrodes are measured. These changes are caused by diference in the permittivity of that material. From these capacitance measurements, an image based on the variation of the permittivity of the cross section contents can be obtained. In this study a numerical model using combine COMSOL MULTIPHYSICS v3.5 and MATLAB 2008a for imaging of an object was developed. Three different position of rectangular sensor: 1-sided sensor, 3-sided and U-shape sensor was designed and analyzed. 1-sided sensor displayed comparatively more uniform in both radial and axial direction in the comparisons of sensitivity distribution.</p>
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Avudaiappan, Siva, Supriya Prakatanoju, Mugahed Amran, Radhamanohar Aepuru, Erick I. Saavedra Flores, Raj Das, Rishi Gupta, Roman Fediuk, and Nikolai Vatin. "Experimental Investigation and Image Processing to Predict the Properties of Concrete with the Addition of Nano Silica and Rice Husk Ash." Crystals 11, no. 10 (October 12, 2021): 1230. http://dx.doi.org/10.3390/cryst11101230.
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The use of the combination of ultrafine rice husk ash (RHA) and nano silica (NS) enhances the compactness of hardened concrete, but there is still a lack of studies that address the effects of NS and RHA on the workability, mechanical properties and pore microstructure of concrete. This study mainly aims to investigate the influence of the pore size distribution in multiphysics concrete model modified by NS and RHA and to determine the workability and mechanical properties of concrete with NS and RHA. In this work, NS and RHA were used as 0, 5, 10, 15 and 20% replacements of ordinary Portland cement (OPC) in concrete grade M20. Concrete mixed with NS and RHA showed improved performance for up to 10% addition of NS and RHA. Further addition of NS and RHA showed a decrease in performance at 7, 14 and 28 days. The decrease in concrete porosity was also found to be up to 10% when adding NS and RHA to cement. Image processing was performed on the cement-based materials to describe the microstructure of the targeted material without damage. The results from the experimental and tomography images were utilized to investigate the concrete microstructure and predict its inner properties.
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Janicijevic, Milovan, Milesa Sreckovic, Branka Kaludjerovic, Mirko Dinulovic, Zoran Karastojkovic, Predrag Jovanic, and Zorica Kovacevic. "Evaluation of laser beam interaction with carbon based material - glassy carbon." Chemical Industry and Chemical Engineering Quarterly 21, no. 1-1 (2015): 63–69. http://dx.doi.org/10.2298/ciceq140131006j.
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Laser beam interaction with carbon based material (glassy carbon) is analyzed in this paper. Nd3+:YAG laser beam (1.06?m i.e. near infrared, NIR range) in ms regime with various energy densities is used. In all experiments, provided in applied working regimes, the surface damages have occurred. The results of laser damages are analyzed by light and electron scanning (SEM) microscopies. Program Image J is executed for quantitative analysis of generated damages based on micrographs obtained by light and SEM microscopes. Temperature distribution in exposed samples is evaluated by numerical simulations based on program packages COMSOL Multiphysics 3.5 in limited energy range.
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Rabbani, Arash, Brittany Wojciechowski, and Bhisham Sharma. "Imaging based pore network modeling of acoustical materials." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A361. http://dx.doi.org/10.1121/10.0019165.
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The acoustical behavior of porous materials is dictated by their underlying pore network geometry. Given the complexity of accurately characterizing the various pore network features, current acoustical models instead rely on indirectly incorporating these features by accounting for them within acoustical transport properties, such as tortuosity, viscous and thermal characteristic lengths, and flow resistivity. In turn, these transport properties are currently identified using inverse characterization techniques or using multiphysics modeling techniques. Here, we propose the use of advanced image processing methods to characterize the pore network of acoustical materials and allow the direct calculation of their transport and acoustical properties. To establish the feasibility of this idea, we create 3D printable CAD models of porous materials with controlled pore geometries and use a Matlab-based watershed segmentation technique to calculate their effective pore and throat size distributions. These distributions are then used to calculate their transport properties and predict their sound absorption coefficients using the Johnson–Champoux–Allard model. For comparison, we calculate the transport properties using the hybrid multiphysics modeling technique and the inverse characterization method. The predictions from the three different methods are then compared with experimental measurements obtained by printing and testing the models using an impedance tube.
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Handayani, Nita, Kharisma Fajar H, Freddy Haryanto, Siti Nurul K, Marlin R. Baidillah, and Warsito P. Taruno. "Simulasi Rekonstruksi Citra Pada Sensor Brain ECVT (Electrical Capacitance Volume Tomography) dengan Metode ILBP (Iterative Linear Back Projection)." INDONESIAN JOURNAL OF APPLIED PHYSICS 6, no. 02 (February 28, 2017): 107. http://dx.doi.org/10.13057/ijap.v6i02.1480.
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<p>The purpose of this study is to simulate the sensor 32-channel Brain ECVT image reconstruction using ILBP (Iterative Linear Back Projection) methods. ECVT is a dynamic volume imaging technique that utilizes non-linear difference of electric field distribution to determine the distribution of permittivity in the sensing area. ECVT has measured the capacitance of data as a result of changes in the permittivity distribution between the electrode pairs. ECVT device consists of three main parts: helmet-shaped sensors, DAS (Data Acquisition System), PC for display and image reconstruction process. Simulation of sensor design using COMSOL Multiphysics 3.5 software, while the process of image reconstruction and analysis of the results using Matlab software 2009a. The principle of ECVT includes two stages of data collection capacitance of electrodes (forward problem) and image reconstruction from the measured capacitance (inverse problem). In the study, the simulation of image reconstruction was done by varying the object position, the number of objects and charge density of the object. From the simulation results showed that the reconstructed image with ILBP method is influenced by several parameters: the object's position in the sensor,charge density value of the object, an alpha value and the number of iterations was selected.</p>
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Zhan, Zhigang, Hao Song, Xiaoxiang Yang, Panxing Jiang, Rui Chen, Hesam Bazargan Harandi, Heng Zhang, and Mu Pan. "Microstructure Reconstruction and Multiphysics Dynamic Distribution Simulation of the Catalyst Layer in PEMFC." Membranes 12, no. 10 (October 14, 2022): 1001. http://dx.doi.org/10.3390/membranes12101001.
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Due to the complexity of both material composition and the structure of the catalyst layer (CL) used in the proton-exchange membrane fuel cell (PEMFC), conjugated heat and mass transfer as well as electrochemical processes simultaneously occur through the CL. In this study, a microstructure model of CL was first reconstructed using images acquired by Nano-computed tomography (Nano-CT) of a real sample of CL. Then, the multiphysics dynamic distribution (MPDD) simulation, which is inherently a multiscale approach made of a combination of pore-scale and homogeneous models, was conducted on the reconstructed microstructure model to compute the corresponded heat and mass transport, electrochemical reactions, and water phase-change processes. Considering a computational domain with the size of 4 um and cube shape, this model consisting of mass and heat transport as well as electrochemical reactions reached a stable solution within 3 s as the convergence time. In the presence of sufficient oxygen, proton conduction was identified as the dominant factor determining the strength of the electrochemical reaction. Additionally, it was concluded that current density, temperature, and the distribution of water all exhibit similar distribution trends, which decrease from the interface between CL and the proton-exchange membrane to the interface between CL and the gas-diffusion layer. The present study not only provides an in-depth understanding of the mass and heat transport and electrochemical reaction in the CL microstructure, but it also guides the optimal design and fabrication of CL components and structures, such as improving the local structure to reduce the number of dead pores and large agglomerates, etc.
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Cunha, Cristina, Catarina Monteiro, António Vaz, Susana Silva, Orlando Frazão, and Susana Novais. "Enhanced Sensitivity in Optical Sensors through Self-Image Theory and Graphene Oxide Coating." Sensors 24, no. 3 (January 30, 2024): 891. http://dx.doi.org/10.3390/s24030891.
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This paper presents an approach to enhancing sensitivity in optical sensors by integrating self-image theory and graphene oxide coating. The sensor is specifically engineered to quantitatively assess glucose concentrations in aqueous solutions that simulate the spectrum of glucose levels typically encountered in human saliva. Prior to sensor fabrication, the theoretical self-image points were rigorously validated using Multiphysics COMSOL 6.0 software. Subsequently, the sensor was fabricated to a length corresponding to the second self-image point (29.12 mm) and coated with an 80 µm/mL graphene oxide film using the Layer-by-Layer technique. The sensor characterization in refractive index demonstrated a wavelength sensitivity of 200 ± 6 nm/RIU. Comparative evaluations of uncoated and graphene oxide-coated sensors applied to measure glucose in solutions ranging from 25 to 200 mg/dL showed an eightfold sensitivity improvement with one bilayer of Polyethyleneimine/graphene. The final graphene oxide-based sensor exhibited a sensitivity of 10.403 ± 0.004 pm/(mg/dL) and demonstrated stability with a low standard deviation of 0.46 pm/min and a maximum theoretical resolution of 1.90 mg/dL.
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Furlan, Rogerio, Joel A. M. Rosado, and Ana Neilde Rodrigues Da Silva. "Formation of Oriented Fibers Using Injection of PEO Solutions inside Electric Fields Defined by Two Parallel Suspended Electrodes." Journal of Integrated Circuits and Systems 6, no. 2 (December 27, 2011): 122–26. http://dx.doi.org/10.29292/jics.v6i2.348.
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Formation of oriented fibers using injection of polyethylene oxide (PEO) solutions inside electric fields defined by two parallel suspended electrodes is investigated. Images of streams formed with the injection of a large amount of polymeric solution reveal good agreement with electric field distributions obtained with numerical simulation (COMSOL Multiphysics) when appropriate boundary conditions are defined. Oriented fibers with diameters in the range of hundreds of nanometers to micrometers result connected between electrodes (separated by several centimeters) and can be easily collected/transferred keeping their orientation. Fibers with this characteristic find applications in topics such as tissue and sensors engineering. Also, the fibers are flexible and can be shaped with the stylus of a profilometer.
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Daniel, Jackson, A. Abudhahir, and J. Janet Paulin. "Tsallis Entropy Segmentation and Shape Feature-based Classification of Defects in the Simulated Magnetic Flux Leakage Images of Steam Generator Tubes." International Journal of Pattern Recognition and Artificial Intelligence 34, no. 01 (May 29, 2019): 2054002. http://dx.doi.org/10.1142/s0218001420540026.
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Early detection of water or steam leaks into sodium in the steam generator units of nuclear reactors is an important requirement from safety and economic considerations. Automated defect detection and classification algorithm for categorizing the defects in the steam generator tube (SGT) of nuclear power plants using magnetic flux leakage (MFL) technique has been developed. MFL detection is one of the most prevalent methods of pipeline inspection. Comsol 4.3a, a multiphysics modeling software has been used to obtain the simulated MFL defect images. Different thresholding methods are applied to segment the defect images. Performance metrics have been computed to identify the better segmentation technique. Shape-based feature sets such as area, perimeter, equivalent diameter, roundness, bounding box, circularity ratio and eccentricity for defect have been extracted as features for defect detection and classification. A feed forward neural network has been constructed and trained using a back-propagation algorithm. The shape features extracted from Tsallis entropy-based segmented MFL images have been used as inputs for training and recognizing shapes. The proposed method with Tsallis entropy segmentation and shape-based feature set has yielded the promising results with detection accuracy of 100% and average classification accuracy of 96.11%.
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Song, Rui, Mengmeng Cui, Jianjun Liu, P. G. Ranjith, and Yun Lei. "A Pore-Scale Simulation on Thermal-Hydromechanical Coupling Mechanism of Rock." Geofluids 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/7510527.
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Thermal-hydromechanical (THM) coupling process is a key issue in geotechnical engineering emphasized by many scholars. Most existing studies are conducted at macroscale or mesoscale. This paper presents a pore-scale THM coupling study of the immiscible two-phase flow in the perfect-plastic rock. Assembled rock matrix and pore space models are reconstructed using micro-CT image. The rock deformation and fluid flow are simulated using ANSYS and CFX software, respectively, in which process the coupled physical parameters will be exchanged by ANSYS multiphysics platform at the end of each iteration. Effects of stress and temperature on the rock porosity, permeability, microstructure, and the displacing mechanism of water flooding process are analyzed and revealed.
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Hua, Chengjian, Yanping Bao, and Min Wang. "Multiphysics Numerical Simulation Model and Hydraulic Model Experiments in the Argon-Stirred Ladle." Processes 10, no. 8 (August 10, 2022): 1563. http://dx.doi.org/10.3390/pr10081563.
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The argon-stirred ladle is a standard piece of steelmaking refining equipment. The molten steel quality will improve when a good argon-stirred process is applied. In this paper, a Multiphysics model that contained fluid flow, bubble transport, alloy transport, bubble heat flux, alloy heat flux, alloy melting, and an alloy concentration species transport model was established. The fluid model and bubble transport model that were used to calculate the fluid velocity were verified by the hydraulic model of the ladle that was combined with particle image velocimetry measurement results. The numerical simulation results of the temperature fields and steel–slag interface shape were verified by a ladle that contained 25 t of molten steel in a steel plant. The velocity difference between the hydraulic model and numerical model decreased when the CL (integral time-scale constant) increased from 0 to 0.3; then, the difference increased when the CL increased from 0.3 to 0.45. The results showed that a CL of 0.3 approached the experiment results more. The bubble heat flux model was examined by the industrial practice, and the temperature decrease rate was 0.0144 K/s. The simulation results of the temperature decrease rate increased when the initial bubble temperature decreased. When the initial bubble temperature was 800 °C, the numerical simulation results showed that the temperature decrease rate was 0.0147 K/s, and the initial bubble temperature set at 800 °C was more appropriate. The average melting time of the alloy was 12.49 s and 12.71 s, and the mixture time was approximately the same when the alloy was added to two slag eyes individually. The alloy concentration had fewer changes after the alloy was added in the ladle after 100 s.
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Gonzalez, Andres, Lawrence Kanyan, Zoya Heidari, and Olivier Lopez. "Integrated Multiphysics Workflow for Automatic Rock Classification and Formation Evaluation Using Multiscale Image Analysis and Conventional Well Logs." Petrophysics – The SPWLA Journal of Formation Evaluation and Reservoir Description 61, no. 5 (October 1, 2020): 495–518. http://dx.doi.org/10.30632/pjv61n5-2020a7.
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Zulkiflli, N. A., M. D. Shahrulnizahani, X. F. Hor, F. A. Phang, M. F. Rahmat, A. W. Y. Khang, Z. Zakaria, R. Mohamed, P. L. Leow, and J. Pusppanathan. "Electrical Capacitance Tomography (ECT) Electrode Size Simulation Study for Cultured Cell." Journal of Physics: Conference Series 2071, no. 1 (October 1, 2021): 012052. http://dx.doi.org/10.1088/1742-6596/2071/1/012052.
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Abstract Cell sensing and monitoring using capacitive sensors are widely used in cell monitoring because of the flexible and uncomplicated design and fabrication. Previous work from many different fields of applications has integrated capacitive sensing technique with tomography to produce cross-sectional images of the internal dielectric distribution. This paper carried an investigation on the capabilities of four 16-channel sensor electrodes with different electrode sizes to detect the change in the dielectric distribution of the cultured cells. All three 16-channel sensor electrodes are designed and simulate on COMSOL 6.3a Multiphysics. The pre-processing results obtained from three finite element models (FEM) of ECT sensor configurations in detecting the cell phantom shows that bigger electrodes size are more sensitive to permittivity distribution.
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Jin, Xinfang, Puvikkarasan Jayapragasam, and Yasser Shoukry. "Multiphysics Modeling for Solid Oxide Electrolyzer Cell with Heterogenous Synthetic Microstructure." ECS Meeting Abstracts MA2023-01, no. 54 (August 28, 2023): 163. http://dx.doi.org/10.1149/ma2023-0154163mtgabs.
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Solid oxide fuel cell (SOFC) and electrolyzer cell (SOEC) are the main focus for researchers in recent times to diminish greenhouse gas emissions and meet cleaner energy demand, as these devices have highest energy conversion rates and efficiencies [1]. The major hinderance in commercializing SOEC is due to its faster cell degradation under higher current density, compared against its SOFC counterpart. The delamination of oxygen electrode (OE) from the electrolyte (EL) is one of the major causes for the cell degradation [2]. We employed a multi-physics numerical model to understand the electrochemical performance of a SOEC half-cell more precisely at a microscale. In this study, widely used mixed ionic and electronic conductor (MIEC) La1-xSrxCo1-yFeyO3-d (LSCF) and Gadolinium-doped Ceria (GDC) composite is used as the oxygen electrode and, pure ionic conductor 8 mol% Y2O3 doped ZrO2 (YSZ) is used as the electrolyte. A GDC buffer layer is tucked in between to prevent undesirable side reactions between OE and EL during long term polarization operation. Until now, a homogenous OE structure has commonly been used with effective physicochemical properties to predict the performance of SOFC/SOEC [3,4]. Only a few researchers have worked on heterogenous microstructure model [5] and simulated the electrochemical performance of the cell. Synthetic microstructure of LSCF-GDC porous electrode as shown in Figure 1 are constructed with an opensource software Dream 3D with particle size ranging from 0.45um - 1.5um. We developed in-house Matlab code for labelling domains, interfaces (2PB and 3PB) and digitally removing the unconnected phases to reduce numerical instabilities while solving the mathematical model in COMSOL Multiphysics 6.0. Mesh in these domains is constructed using Iso2Mesh toolbox [6] and translated as mphtxt file which is later imported into COMSOL. This practice reduces the computational time and memory. We employed Nernst-Planck theory for solving the transport of species like vacancy, hole and electron within LSCF inside OE. Multi-step charge transfer at two phase boundary (2PB) and triple phase boundary (3PB) interfaces for oxygen evolution reaction are formulated by Butler-Volmer expressions [4]. A physics-based impedance model under DC bias is developed to separate the electrochemical contributions from 2PB and 3PB transport pathways. The voltage-current curve during long-term polarization test is coupled with the model for validation and approximation of process parameters. Furthermore, we will simulate the crack propagation at OE-buffer layer interface in various directions and orientations to understand the failure mechanism on the synthetically constructed microstructure. References: A. Laguna-Bercero, “Recent advances in high temperature electrolysis using solid oxide fuel cells: a review”, J. Power Sources, vol. 203, no. 4, 2012 N. Rashkeev and M. V. Glazoff, “Atomic-scale mechanisms of oxygen electrode delamination in solid oxide electrolyzer cells”, Int. J. Hydrogen Energy, vol. 37, no. 2, pp. 1280–1291, 2012 Pakalapati, K. Gerdes, H. Finklea, M. Gong, X. Liu and I. Celik, “Micro scale dynamic modeling of LSM/YSZ composite cathodes”, Solid State Ionics, vol. 258, pp. 45-60, 2014 Cook, J. Wrubel, Z. Ma, K. Huang, X. Jin, “Modeling Electrokinetics of Oxygen Electrodes in Solid Oxide Electrolyzer Cells”, Journal of The Electrochemical Society, vol. 168, no. 11, pp. 114510, 2021 Su, Z. Zhong and Z. Jiao, “A novel multi-physics coupled heterogenous single-cell numerical model for solid oxide fuel cell based on 3D microstructure reconstructions”, Energy & Environmental Science, vol. 15 pp. 2410 – 2424, 2022 Fang and D. Boas, “Tetrahedral mesh generation from volumetric binary and grayscale images”, Proceedings of IEEE International Symposium on Biomedical Imaging, 2009, pp. 1142–1145 Figure 1
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Li, Yan, Ze Yun, Xiang Zhou, and Chuansong Wu. "Fundamental understanding of open keyhole effect in plasma arc welding." Physics of Fluids 35, no. 4 (April 2023): 043316. http://dx.doi.org/10.1063/5.0144148.
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The keyhole arc welding technique has the advantage of improving welding efficiency by utilizing a stable keyhole mode. Accurate understanding of the keyhole effect is necessary to enhance the welding quality. Due to the high temperature and strong arc force involved, the complex gas–liquid–solid interactions in the complete keyhole process need to be explored. In order to fully demonstrate open keyhole mode welding, a three-tier sandwiched model based on multiphysics and multiphase effects was developed. The top layer of the model is filled with plasma arc, which gradually fuses and penetrates through the middle metal layer. Finally, it enters the third layer, resulting in an open keyhole mode. Multiphysics phenomena due to the plasma arc are fully included in the model, and the gas–liquid–solid interactions are calculated by combining the Volume of Fluid technique and the Enthalpy-porous technique. Arc ignition and dynamic open keyhole effect are demonstrated, and an arc discharge is shown from the open keyhole exit. The arc reflection phenomenon is observed as the arc is blocked by the weld pool frontier. The electric current path varies with the welding movement, and most of the current comes from the weld pool frontier. An experiment was conducted to obtain weld pool and keyhole images, which basically agree with the calculated results. Additionally, the calculated open keyhole time and electric potential drops also coincide well with experimental data.
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Zagubisalo, Peter S., Andrey G. Paulish, and Sergey A. Kuznetsov. "Simulation of thermal processes in metamaterial millimeter-wave to infrared converter for millimeter-wave imager." International Journal of Modeling, Simulation, and Scientific Computing 05, supp01 (October 2014): 1441009. http://dx.doi.org/10.1142/s1793962314410098.
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The main characteristics of millimeter-wave (MM-wave) image detector were simulated by means of accurate numerical modeling of thermophysical processes in a metamaterial MM-to-IR converter. The converter represents a multilayer structure consisting of an ultra thin resonant metamaterial absorber and a perfect emissive layer. The absorber consists of a dielectric self-supporting film that is metallized from both sides. A micro-pattern is fabricated from one side. Resonant absorption of the MM waves induces the converter heating that yields enhancement of IR emission from the emissive layer. IR emission is detected by IR camera. In this contribution an accurate numerical model for simulation of the thermal processes in the converter structure was created by using COMSOL Multiphysics software. The simulation results are in a good agreement with experimental results that validates the model. The simulation shows that the real-time operation is provided for the converter thickness less than 3 μm and time response can be improved by decreasing of the converter thickness. The energy conversion efficiency of MM waves into IR radiation is over 80%. The converter temperature increase is a linear function of a MM-wave radiation power within three orders of the dynamic range. The blooming effect and ways of its reducing are also discussed. The model allows us to choose the ways of converter structure optimization and improvement of image detector parameters.
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Yang, Jixin, Pengliang Yu, Suran Wang, and Zheng Sun. "CO2 Storage Monitoring via Time-Lapse Full Waveform Inversion with Automatic Differentiation." Nanomaterials 14, no. 2 (January 7, 2024): 138. http://dx.doi.org/10.3390/nano14020138.
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In the field of CO2 capture utilization and storage (CCUS), recent advancements in active-source monitoring have significantly enhanced the capabilities of time-lapse acoustical imaging, facilitating continuous capture of detailed physical parameter images from acoustic signals. Central to these advancements is time-lapse full waveform inversion (TLFWI), which is increasingly recognized for its ability to extract high-resolution images from active-source datasets. However, conventional TLFWI methodologies, which are reliant on gradient optimization, face a significant challenge due to the need for complex, explicit formulation of the physical model gradient relative to the misfit function between observed and predicted data over time. Addressing this limitation, our study introduces automatic differentiation (AD) into the TLFWI process, utilizing deep learning frameworks such as PyTorch to automate gradient calculation using the chain rule. This novel approach, AD-TLFWI, not only streamlines the inversion of time-lapse images for CO2 monitoring but also tackles the issue of local minima commonly encountered in deep learning optimizers. The effectiveness of AD-TLFWI was validated using a realistic model from the Frio-II CO2 injection site, where it successfully produced high-resolution images that demonstrate significant changes in velocity due to CO2 injection. This advancement in TLFWI methodology, underpinned by the integration of AD, represents a pivotal development in active-source monitoring systems, enhancing information extraction capabilities and providing potential solutions to complex multiphysics monitoring challenges.
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Qiu, Cheng, Anam Abbas, and Feruza Amirkulova. "Pentamode metamaterial design via generative modeling and deep learning." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A255. http://dx.doi.org/10.1121/10.0011241.
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In this talk, the deep learning-assisted models will be presented for the design of pentamode unit cells to construct a 3-D lattice structure that can mimic the acoustic properties of water. The pentamode models were implemented and modified by altering the properties of the structure during the full-wave simulation performed on COMSOL Multiphysics software to ensure they meet the requirements of specific appliances for manufacture. The design is further improved by the inverse design technique. The implementation of conditional Wasserstein Generative Adversarial Networks with gradient penalty (cWGAN-GP) for the inverse design will be illustrated by showing examples of 3-D titanium pentamode structures on the hexagonal lattice. The cWGAN was set up using critic and generator with CoordConv layers, along with regressor to produce images matching the desired labels. The convolutional neural network was used as an auxiliary regressor to predict all design parameters for the cell images. The expected PM lattice structure has a high bulk modulus, low-shear modulus and behaves as metal water at a broad range of frequencies including higher frequencies.
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Zhang, Yuejin, Mengqiu Ye, Juan Wang, Guanghui Li, Meiling Zhong, and Aiyun Zhan. "Modeling analysis of microenvironment of 3D cell mechanics based on machine vision." Open Physics 20, no. 1 (January 1, 2022): 117–29. http://dx.doi.org/10.1515/phys-2022-0013.
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Abstract Aiming at the problem of poor construction accuracy of the cellular three-dimensional (3D) mechanical microenvironment, this article studies the cellular 3D mechanical microenvironment based on machine vision. The gelatin methacrylate microgel column was prepared by NIH/3T3 mouse fibroblast and precursor solution of gelatin methacrylate microgel. The gelatin methacrylate microgel array with magnetic end was adopted. The external magnetic field was used to load microgel array and build 3D mechanics microenvironment model. The deformed pictures of hydrogel under magnetic field were obtained by fluorescence microscope. The scanning electron microscope was used to characterize the pore structure of gelatin methacrylate hydrogel. The pictures obtained by machine vision method were used to calculate the deformed parameters of sample. The machine vision method adopted the discrete cosine transform for autofocus, and then used the image analysis and processing technology to identify and estimate the cell motion parameters. After getting the cell motion parameters, Comsol multiphysics (COMSOL) multiphysics multifield coupling finite element analysis software was adopted. The correlative numerical simulation method and gel deformed simulation method were used to obtain the mechanical changes of cells in the 3D mechanical microenvironment. Experimental results show that the modulus of gelatin methacrylate microgel is changed significantly during the tensile loading. The tensile strain and the cell spreading area are nonlinearly related. The increase in stiffness of the hydrogel substrate helps to promote cell proliferation to a certain extent.
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Cooper, L. J., K. R. Daly, P. D. Hallett, M. Naveed, N. Koebernick, A. G. Bengough, T. S. George, and T. Roose. "Fluid flow in porous media using image-based modelling to parametrize Richards' equation." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 473, no. 2207 (November 2017): 20170178. http://dx.doi.org/10.1098/rspa.2017.0178.
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The parameters in Richards' equation are usually calculated from experimentally measured values of the soil–water characteristic curve and saturated hydraulic conductivity. The complex pore structures that often occur in porous media complicate such parametrization due to hysteresis between wetting and drying and the effects of tortuosity. Rather than estimate the parameters in Richards' equation from these indirect measurements, image-based modelling is used to investigate the relationship between the pore structure and the parameters. A three-dimensional, X-ray computed tomography image stack of a soil sample with voxel resolution of 6 μm has been used to create a computational mesh. The Cahn–Hilliard–Stokes equations for two-fluid flow, in this case water and air, were applied to this mesh and solved using the finite-element method in COMSOL Multiphysics. The upscaled parameters in Richards' equation are then obtained via homogenization. The effect on the soil–water retention curve due to three different contact angles, 0°, 20° and 60°, was also investigated. The results show that the pore structure affects the properties of the flow on the large scale, and different contact angles can change the parameters for Richards' equation.
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Soleimani, Hassan, Hassan Ali, Noorhana Yahya, Leila Khodapanah, Maziyar Sabet, Birol M. R. Demira, and Gregory Kozlowski. "Dynamics and Geometry Effects on the Capillary Flows in Porous Media for Enhanced Oil Recovery." Defect and Diffusion Forum 413 (December 17, 2021): 77–83. http://dx.doi.org/10.4028/www.scientific.net/ddf.413.77.
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The continuing depletion of light oil supplies and the rapidly growing demand for energy are forcing oil and gas companies to explore unconventional oil extraction techniques. The structure and flow rate implies an impact on the trapping and mobilization of oil in the reservoir. This article studies the effect of pore geometry and dynamics on water-oil displacement as a two-phase flow system. The pore geometries of sandstone were extracted using the non-destructive 3D micro computational tomography (micro-CT) technique. Two-phase flow simulations were performed using COMSOL Multiphysics on the micro-CT images to show the effect of the capillary number and the flow pattern. Velocity and relative permeability of the non-wetting phase at different points of the porous structure was computed. The effect of viscosity of wetting fluid on the pore structure was also studied to evaluate the parameters affecting enhanced oil recovery (EOR).
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Hassanabadi, Massoud, Shahid Akhtar, and Ragnhild E. Aune. "Study and Modelling of Fluid Flow in Ceramic Foam Filters." Materials 16, no. 17 (August 30, 2023): 5954. http://dx.doi.org/10.3390/ma16175954.
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To investigate the fluid flow characteristics of conventional Ceramic Foam Filters (CFFs) of grades 30 and 50, a 2D macro-scale geometry was generated by converting pixel grid images of the filters into vector format images. The flow behaviour through the filter channels was then numerically modelled using the Stocks equation within the Creeping Flow interface of COMSOL Multiphysics®. Through modelling, the average interstitial velocity was estimated and found to be higher than the corresponding value obtained from the Dupuit–Forchheimer equation. The discrepancy obtained suggested that the flow behaviour within the filter channels differed from that based on the simplified assumptions of the equation. The porosity and permeability of the CFFs were evaluated during the post-processing stage using surface integration and user-defined equations. The experimentally determined porosity closely matched the values obtained from the simulation model, demonstrating the reliability of the numerical approach. However, the permeability values from the simulation of CFFs of grades 30 and 50 were higher than those obtained experimentally. This discrepancy can be attributed to the larger channels in the generated geometrical pattern compared to the original CFF structure. The present findings highlight the effectiveness of the proposed methodology in developing a representative macro-scale geometry for CFFs and in simulating fluid flow behaviour.
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Hanon, Muammel M., Ziad A. Taha, and László Zsidai. "Simulation of laser drilling of Inconel X-750 and Ti-5Al-2.5Sn sheets using COMSOL." Acta Polytechnica 61, no. 4 (August 31, 2021): 526–36. http://dx.doi.org/10.14311/ap.2021.61.0526.
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The ability of COMSOL Multiphysics 5.2 software to carry out the simulation of laser drilling processes in Inconel X-750 and Ti-5Al-2.5Sn sheets was investigated in this study. A JK 701 pulsed Nd:YAG laser was used for drilling through the entire depth of Inconel X-750 and Ti-5Al-2.5Sn plates of 2 mm and 3 mm thicknesses using laser pulses of a millisecond in time. The laser parameters are varied in different combinations for well-controlled drilling through the entire thickness of the plates. Effects of laser peak power and pulse duration have been determined via the studying of the temperature distribution on the cross-section of the images taken in the simulation tests. Characterizing the optimum conditions obtained from the combination of parameters that improve hole quality is an essential aim in this paper. This work's outcomes might be helpful for researchers in terms of the optimum parameters proposed when studying the laser drilling of the mentioned alloys experimentally.
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Xu, Minming, and Yun Ouyang. "Exploration of Flood Prediction in Watersheds Based on the Fusion Analysis of Remote Sensing Big Data with Multiple Physical Fields." Journal of Function Spaces 2022 (July 16, 2022): 1–10. http://dx.doi.org/10.1155/2022/9422553.
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It is well known that flooding brings great losses to people’s production and life, just because it is unsuspected, is extremely extensive, and has high frequency. More than half of the people in China live in flood-prone areas, and their lives and properties are threatened. Flood risk assessment is one of the measures of flood management, and it is economically and socially important to assess flood risk. The scope of the traditional monitoring and forecasting early warning system is mainly limited to the area affected by flash floods, while the objective reality of real-time monitoring, forecasting, and early warning of flood disasters in the area affected by river floods and by the scheduling of riverine terrace power stations is not possible. The multiphysics remote sensing big data fusion analysis can divide the data into grids according to the grid method in the sliding time window, filter the normal data by information entropy in each grid, judge the remaining data that may be abnormal by using local abnormality factor, and eliminate the abnormal data according to the judgment result. This paper introduces the application of remote sensing in flood control field, proposes the framework of basin flood prediction based on multiphysics field remote sensing big data fusion analysis, and designs each functional module of the system according to the object-oriented idea to realize the functions of data management, image processing, spatial analysis, and simulation output. The method can change the problems of cumbersome data processing and basic parameter rate determination in traditional hydrological methods and can find certain regularity through the connection between all related factors. Meanwhile, the use of artificial intelligence and other technical means makes the calculation speed faster and the obtained results are closer to the actual measured values, which is beneficial to guide the practical work.
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Kabachek, V. V., N. S. Davydova, M. M. Mezhennaya, and M. V. Davydov. "Anthropomorphic Brain Models Based on Magnetic Resonance Imaging." Digital Transformation 28, no. 2 (September 2, 2022): 61–69. http://dx.doi.org/10.35596/2522-9613-2022-28-2-61-69.
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The article is devoted to the creation of a method for generating anthropomorphic brain models based on magnetic resonance imaging. The selection of the magnetic field amplitude for transcranial magnetic stimulation (TMS) is carried out through modeling using the finite element method (FEM). These FEM models graphically demonstrate information on the distribution of the magnetic field and, therefore, on the occurring neurophysiological and behavioral changes based on the dose of the TMS, the specific resistance of the head tissue and its anatomy. Thus, these models are an integral tool used to design, configure, and program TMS devices, as well as to study parameters such as magnetic field strength and tension. A distinctive aspect of this work is the quality of the resulting head models. When creating the calculated FEM models, an MRI image of the head was used to perform segmentation in the FreeSurfer environment. Next, the image was converted in the Matlab environment. After the assembly of the head model in COMSOL Multiphysics, the TMS was simulated. The results of the transformations is a head model made in the form of a three-dimensional grid, which is suitable for modeling. The obtained data can be used to personalize the TMS method in medicine.
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Гревцев, А. C., П. А. Золотухин, Э. А. Ильичев, Г. Н. Петрухин, А. В. Попов, and Г. С. Рычков. "Расчетная модель приемника тепловых изображений в архитектуре электронно-оптического преобразователя." Журнал технической физики 92, no. 4 (2022): 507. http://dx.doi.org/10.21883/jtf.2022.04.52237.270-21.
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An innovative design is considered, and the results of analysis and calculations of the characteristics of a thermal image receiver (3-15 microns), made in the electron-optical converter architecture, are presented. For the sensor-converting pyroelectric unit of the electron-optical converter, the spatial dependences of the electric field strengths and the values of the electric potentials on the spontaneous polarization of the film substance are calculated. Estimates are obtained and the characteristics of thermal-field-induced polarization of various pyroelectric films are discussed. The temperature dependences of the polarization characteristics of a number of pyroelectric films are calculated using the finite element method in the COMSOL Multiphysics software package. Possible contributions of the piezoelectric effect to the picture of the distribution of electric potentials from the thermal polarization of pyroelectric films are taken into account. Estimates are obtained for the limiting values of the main instrument characteristics of the electron-optical converter.
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Stavropoulou, Eleni, and Lyesse Laloui. "Insights into the interaction of a shale with CO2." Solid Earth 13, no. 12 (December 5, 2022): 1823–41. http://dx.doi.org/10.5194/se-13-1823-2022.
Full textAbstract:
Abstract. Caprock formations, such as shales, play a key role in safe underground CO2 storage since they serve as a hydromechanical barrier that prevents migration of the injected CO2 to the surface. While their hydromechanical response is important to ensure their sealing capacity, interaction with the injected CO2 involves additional thermo–hydro–chemo–mechanical (THCM) phenomena that may threaten the long-term integrity of the caprock. The low-transport properties of shales make them a suitable caprock material, but at the same time challenging to study due to the very long timescales (months/years) that are required for the various THCM processes to manifest. In this work, the long-term multiphysical interaction of the Opalinus Clay shale with liquid and supercritical CO2 is studied in 3D with live X-ray tomography. Three-dimensional analysis reveals the localised response of the coupled THCM processes that is often indistinguishable with conventional lab testing protocols. To improve spatial and temporal resolution while applying field-representative pressure and temperature conditions, small-sized samples are studied. Long-term injection of liquid CO2 resulted in significant fissuring of calcite-rich zones that were for the first time visualised and quantified from the X-ray images. Additionally, a re-arrangement of the pre-existing micro-fissures in the clay matrix was observed. The volumetric response during direct exposure of an Opalinus Clay sample to supercritical CO2 revealed an initial swelling at pre-fissured zones and initiation of new micro-fissures at areas of direct contact with the anhydrous CO2 due to pore water evaporation. Advanced 3D image analysis showed an increasing CO2 uptake in the caprock material with time, suggesting potential CO2 trapping in the material.