Realistic 3D Geometry Research Articles

Enhanced Tailings Dam Beach Line Indicator Observation and Stability Numerical Analysis: An Approach Integrating UAV Photogrammetry and CNNs

Tailings ponds are recognized as significant sources of potential man-made debris flow and major environmental disasters. Recent frequent tailings dam failures and growing trends in fine tailings outputs underscore the critical need for innovative monitoring and safety management techniques. Here, we propose an approach that integrates UAV photogrammetry with convolutional neural networks (CNNs) to extract beach line indicators (BLIs) and conduct enhanced dam safety evaluations. The significance of real 3D geometry construction in numerical analysis is investigated. The results demonstrate that the optimized You Only Look At CoefficienTs (YOLACT) model outperforms in recognizing the beach boundary line, achieving a mean Intersection over Union (mIoU) of 72.63% and a mean Pixel Accuracy (mPA) of 76.2%. This approach shows promise for future integration with autonomously charging UAVs, enabling comprehensive coverage and automated monitoring of BLIs. Additionally, the anti-slide and seepage stability evaluations are impacted by the geometry shape and water condition configuration. The proposed approach provides more conservative seepage calculations, suggesting that simplified 2D modeling may underestimate tailings dam stability, potentially affecting dam designs and regulatory decisions. Multiple numerical methods are suggested for cross-validation. This approach is crucial for balancing safety regulations with economic feasibility, helping to prevent excessive and unsustainable burdens on enterprises and advancing towards the goal of zero harm to people and the environment in tailings management.

Sensitivity analysis of transabdominal fetal pulse oximetry using MRI-based simulations.

Transabdominal fetal pulse oximetry offers a promising approach to improve fetal monitoring and reduce unnecessary interventions. Utilizing realistic 3D geometries derived from MRI scans of pregnant women, we conducted photon simulations to determine optimal source-detector configurations for detecting fetal heart rate and oxygenation. Our findings demonstrate the theoretical feasibility of measuring fetal signals at depths up to 30 mm using source-detector (SD) distances greater than 100 mm and wavelengths between 730 and 850 nm. Furthermore, we highlight the importance of customizing SD configurations based on fetal position and maternal anatomy. These insights pave the way for enhanced non-invasive fetal monitoring in clinical application.

A geometry model of the porcine stomach featuring mucosa and muscle layer thicknesses

The stomach is a vital organ responsible for food storage, digestion, and transport. Stomach diseases are of great economic and medical importance and require a large number of bariatric surgeries every year. To improve medical interventions, in silico modeling of the gastrointestinal tract has gained popularity in recent years to study stomach functioning. Because of the great structural and nutritional similarity between the porcine and human stomach, the porcine stomach is a suitable surrogate for the development and validation of gastric models. This study presents a realistic 3D geometry model of the porcine stomach based on a photogrammetric reconstruction of a real organ. Layer thicknesses of the stomach wall's mucosa and tunica muscularis were determined by more than 1900 manual measurements at different locations. Layer thickness distributions show mean mucosal and muscle thicknesses of 2.29 ± 0.45 mm and 2.83 ± 0.99 mm, respectively. In general, layer thicknesses increase from fundus (mucosa: 1.82 ± 0.19 mm, muscle layer: 2.59 ± 0.32 mm) to antrum (mucosa: 2.69 ± 0.31 mm, muscle layer: 3.73 ± 1.05 mm). The analysis of stomach asymmetry with respect to an idealized symmetrical stomach model, an approach often used in the literature, revealed volumetric deviations of 45%, 15%, and 92% for the antrum, corpus, and fundus, respectively. The present work also suggests an algorithm for the computation of longitudinal and circumferential directions at local points. These directions are useful for the implementation of material anisotropy. In addition, we present data on the passive pressure-volume relationship of the organ and perform an exemplary finite-element simulation, where we demonstrate the applicability of the model. We encourage others to utilize the geometry model featuring profound asymmetry for future model-based investigations on stomach functioning.

MRI-based numerical modeling of cardiac pulsed field ablation (PFA) with sub-microsecond pulses

Abstract Background The use of irreversible electroporation (IRE) for cardiac ablation in the management of cardiac arrhythmias, known as Pulsed Field Ablation (PFA), has gained the attention of many researchers, physicians and companies. Despite the demonstrated efficacy and safety profiles of the technique, there are still many open questions. One of them deals with the effective electric field thresholds necessary for cardiac tissue ablation. Contrary to radiofrequency (RF) ablation, where the thermotemporal thresholds for tissue damage are well established, the electric field thresholds for effective IRE are uncertain and depend on the tissue type and the waveform characteristics of the delivered electric field. Purpose The use of numerical models to understand the electric field distribution and the corresponding lesion for a specific electrode geometry are widely used in IRE for cancer treatment. Models can predict ablation volumes when the field thresholds are known or can be used to estimate the field thresholds when the lesion geometry is established post-treatment. The goal of the present study was to build a subject-specific realistic 3D numerical model to assess the ability of modeling to predict PFA lesions. Methods PFA experiments were performed in male mongrel dogs following a protocol approved by the Mayo Clinic Institutional Animal Care and Use Committee. Briefly, animals were sedated and intubated, and two non-irrigated deflectable catheters with an 8-mm tip were positioned on both sides of the interventricular septum under fluoroscopy guidance. Submicrosecond pulses were delivered in a bipolar fashion across both catheters. Sequences of pulses of 300 ns duration (or other durations in that range) were repetitively applied with voltage levels in the kV range. 30 days after the procedure, MRI with late gadolinium enhancement (LGE) were acquired to assess the presence of ablation lesions in the treated tissue. Ventricular areas were segmented from MRI images and 3D volumes were created. The generated 3D geometries were imported into software COMSOL Multiphysics. Realistic 3D geometries of the catheters were placed in the same positions than during the experiments, fluoroscopy videos recorded during the procedures were used as a guidance. The computed electric field intensity distributions were compared to the LGE areas to extract the range of electric field thresholds where the predicted lesion size was compatible with the real size of the LGE areas for each application site and pulsing protocol. Results and conclusions Our results show how the numerical model is able to reproduce the shape of the LGE fibrotic lesion areas observed 30 days after the procedure. Additionally, the model clearly confirms the dose-dependent lesion sizes observed experimentally. This study supports that numerical modeling is a valuable tool for understanding PFA treatments and that it could be used as patient-specific treatment planning tool. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie

Development of a new bio-microscope for 3D geometry characterization of fruit single cells.

Fruit cells are living irregular three-dimensional (3D) transparent objects which makes them challenging to determine their real 3D size and shape through only two-dimensional (2D) images using the existing biological microscope. This study deals with a newly self-developed biological microscope including a microscope imaging system, a light source system, a stage and a support base for the 3D size characterization of fruit single cells. The main design concept is based on two optical path systems set up at the front (x-axis) and bottom (z-axis) directions of a transparent chamber containing single cells that allow the front view and bottom view of the single cell to be observed. Performance indicators such as mass, size, observation range, objective magnification, total magnification, focal range, focal accuracy, and resolution of the developed biological microscope were estimated. Finally, the 3D geometry size of single tomato cells was measured by the new biological microscope to demonstrate the relative ease at which accurate real 3D geometry information of single fruit cells could be obtained, which echoes its scientific value.

Vacuum ultraviolet radiation in and from an atmospheric pressure plasma source

This work presents a computational study of the atmospheric pressure plasma of the COST jet source in He + 0.1% N2 buffer gas, incorporating the treatment of the VUV resonant radiation from He atoms at a wavelength of 58.4 nm. The plasma is driven by single- and multi-frequency waveforms at various peak-to-peak voltages between 400 V and 685 V. The simulations, which include the photoemission of electrons from the electrodes as well as the photoionization of the N2 molecules indicate that these processes, induced by the VUV radiation, have relatively little influence on the discharge characteristics due to other more efficient charged particle production mechanisms, e.g., Penning ionization. While the plasma characteristics are computed along one spatial dimension perpendicular to the electrodes, the tracing of the VUV photons is executed in the real 3D geometry of the plasma source to allow the computation of the VUV photon flux leaving the device through the orifice. Photon fluxes up to cm−2 s−1, corresponding to an energy flux of ≈18 mW cm−2 are found at multi-frequency operation.

High-performance 3D Unstructured Mesh Deformation Using Rank Structured Matrix Computations

The Radial Basis Function (RBF) technique is an interpolation method that produces high-quality unstructured adaptive meshes. However, the RBF-based boundary problem necessitates solving a large dense linear system with cubic arithmetic complexity that is computationally expensive and prohibitive in terms of memory footprint. In this article, we accelerate the computations of 3D unstructured mesh deformation based on RBF interpolations by exploiting the rank structured property of the matrix operator. The main idea consists in approximating the matrix off-diagonal tiles up to an application-dependent accuracy threshold. We highlight the robustness of our multiscale solver by assessing its numerical accuracy using realistic 3D geometries. In particular, we model the 3D mesh deformation on a population of the novel coronaviruses. We report and compare performance results on various parallel systems against existing state-of-the-art matrix solvers.

Performances of the Passive SAR Imaging of Jupiter’s Icy Moons

With the development of the JUICE/RIME (ESA) and Europa-Clipper/REASON (NASA) instruments, designed to study the subsurface of the Galilean moons, interest has been growing to study the performances of sounding radar orbiting these bodies. In the presence of strong Jupiter’s radio emissions, probing in a passive mode using these emissions as the emitter is considered. However, radar performances in this bistatic mode are dependent on the entire geometry of observation: the position of the source of emission, the spacecraft trajectory, and on the region probed. 3D Simulations are necessary to estimate the performances of these measurements. We analyze the influence of the geometry of observation by approximating Jovian radio bursts as radio impulses, simulating the signal scattered by a point target in a realistic 3D geometry and computing the resolution. This allows a preliminary identification of scenarios of observation best suited for this radar mode. The influence of the correct localization of Jupiter’s emissions on the SAR image is investigated as well, and interest in recovering the true position of Jupiter’s source is highlighted.

Spontaneous Ca2+ Fluctuations Arise in Thin Astrocytic Processes With Real 3D Geometry.

Fluctuations of cytosolic Ca2+ concentration in astrocytes are regarded as a critical non-neuronal signal to regulate neuronal functions. Although such fluctuations can be evoked by neuronal activity, rhythmic astrocytic Ca2+ oscillations may also spontaneously arise. Experimental studies hint that these spontaneous astrocytic Ca2+ oscillations may lie behind different kinds of emerging neuronal synchronized activities, like epileptogenic bursts or slow-wave rhythms. Despite the potential importance of spontaneous Ca2+ oscillations in astrocytes, the mechanism by which they develop is poorly understood. Using simple 3D synapse models and kinetic data of astrocytic Glu transporters (EAATs) and the Na+/Ca2+ exchanger (NCX), we have previously shown that NCX activity alone can generate markedly stable, spontaneous Ca2+ oscillation in the astrocytic leaflet microdomain. Here, we extend that model by incorporating experimentally determined real 3D geometries of 208 excitatory synapses reconstructed from publicly available ultra-resolution electron microscopy datasets. Our simulations predict that the surface/volume ratio (SVR) of peri-synaptic astrocytic processes prominently dictates whether NCX-mediated spontaneous Ca2+ oscillations emerge. We also show that increased levels of intracellular astrocytic Na+ concentration facilitate the appearance of Ca2+ fluctuations. These results further support the principal role of the dynamical reshaping of astrocyte processes in the generation of intrinsic Ca2+ oscillations and their spreading over larger astrocytic compartments.

Thermal modeling for breast tumor detection using thermography

The paper aims to complement thermography with numerical analysis in order to use patients’ personalized data such as precise breast geometry and temperature patterns to detect tumors inside the breast. Previous studies in the literature use idealized semi-spherical breast models without experimental validation and personalized data. To improve the accuracy and reliability of computer-aided diagnosis of breast tumors, this study uses realistic 3D breast geometry, based on 3D scanning, in its numerical model, which is then validated by experiments through fabricating the breast using 3D printing and molding. It is shown in the combined numerical and experimental study that breast geometry is very important in determining the temperature field and detecting the tumor inside the breast. Further computational study shows that for breasts with and without tumors for cup sizes ranging from 120 to 260 mm and tumor depth from 5 to 25 mm, the maximum differences in surface temperatures can range from 0.34 to 1.37 °C. The difference become insignificant with large cup sizes. Thus, it can be concluded that the major important factors for precision tumor detection are tumor depth and breast geometry.

Fluid structure interaction study of stenosed carotid artery considering the effects of blood pressure

Atherosclerosis is the most common cardiovascular disease (CVD) causing increased morbidity. Although atherosclerosis is a general disease involving several factors, it preferentially affects the wall of the vessel bifurcations. The use of advanced Computational Fluid Dynamics (CFD) techniques has the potential to shed more light in the further understanding of the causes of the disease and perhaps in its early diagnosis. In this work, a three-dimensional (3D) Fluid Structure Interaction (FSI) study was carried out for a patient specific carotid artery. By considering physiological conditions, first the normal and then with hypertension disease, haemodynamic parameters were evaluated to better understand the genesis and progression of atherosclerotic plaques in the carotid artery bifurcation. Two-way FSI was performed by applying a fully implicit second-order backward Euler differencing scheme using commercial software ANSYS and ANSYS CFX (version 19.0). Arbitrary Lagrangian–Eulerian (ALE) formulation was employed to calculate the arterial response by using the temporal blood response. Due to arterial bifurcation, obvious velocity reduction and backflow formation were observed which decreased shear stress and made it oscillatory at the starting point of the internal carotid artery near the carotid sinus, which resulted in low shear stress. Oscillatory Shear Index (OSI) signifies oscillatory behaviour of artery wall shear stress. By using anatomically realistic 3D geometry and representative physiological conditions, the results obtained for shear stress are more acceptable. Comparison of the results of this study with those in the published literature shows that the regions with low wall shear stress and with OSI value greater than 0.3 pose potential risk to the development of plaques. It was observed that haemodynamics of the carotid artery was very much affected by the geometry and flow conditions. Furthermore, regions of relatively low wall shear stress were observed post stenosis, which is a known cause of plaque development and progression.

Foam EOR performance in homogeneous porous media: simulation versus experiments

In petroleum industry after primary production, associated gas released from separators or an inert gas from an external resource is injected into reservoir to push the oil toward production wells. The most important issue in injection process is that highly mobile fluids prefer to channel through porous media outgoing the oil phase. To overcome this problem, foam is injected into reservoir to increase sweep efficiency via reducing mobility ratio. Foam EOR performance in porous media depends on several factors including foam texture, media characteristics and injection scenarios. In this work, we used {text{MATLAB}} software to numerically simulate foam core flooding and also to fit {text{STARS}} parameters with data achieved from two previously performed foam injection experiments in Bentheimer core samples with lengths of 6.7″ and 15.1″. Then we used {text{CMG}} software to outstretch foam {text{EOR}} simulations to more realistic 2D and 3D geometries which were designed to study override issue in slant formations and also well patterns influence on foam {text{EOR}} performance. Results show that foam {text{EOR}} performance in slant pay zones with severe dip angles highly depends on foam strength, pay zone thickness and injection well location. Results also show that since foam always exhibits shear thinning characteristic, well patterns which use higher number of wider spread injection wells can aid to improve oil extraction efficiency during foam flooding.

A framework for the assessment and control of ITER main chamber heat loads

A control-oriented approach, based on real-time equilibrium reconstruction, has been developed to monitor power fluxes to ITER plasma-facing components (PFC). The model describes the deposited heat flux as a poloidal flux function with two main input parameters: the power exhausted across the plasma boundary and the scrape-off layer heat flux width. A module containing weighting factors accounts for the real PFC 3D geometry. These factors are obtained using a new sophisticated GUI interface, SMITER, hosting a magnetic field line tracing code permitting the import and appropriate meshing of full PFC CAD descriptions. This new methodology has been used to examine two critically important first wall (FW) power loading issues for ITER: the start-up phase at low current and power, but requiring direct contact with the inboard wall, and the case of an upward plasma shift in a diverted configuration under high power, high current H-mode burning plasma conditions, which imposes very high power loads on the upper chamber FW panels.

Three‐dimensional vorticity and time‐constrained evolution of the Main Central Thrust zone, Garhwal Himalaya (NW India)

AbstractVorticity estimates based on porphyroclasts analysis are limited by the extrapolation to three dimensions of two‐dimensional data. We describe a 3D approach based on the use of X‐ray micro‐computed tomography that better reflects the real 3D geometry of the porphyroclasts population. This new approach for kinematic vorticity analysis in the Munsiari Thrust mylonites, the lower boundary of the Main Central Thrust zone (MCTz) in Indian Himalaya, indicates a large pure shear component during non‐coaxial shearing. 40Ar/39Ar ages of micas along the mylonitic foliation of the Munsiari and Vaikrita thrusts (the upper boundary of the MCTz) constrain thrust activity to 5–4 and 8–9 Ma, respectively. Available kinematic vorticity analyses of the Vaikrita mylonites suggest the dominance of a simple shear component. Combining these data, we suggest that the southward and structurally downward shift of deformation along the MCTz was accompanied by a progressive increase in the pure shear component in a general shear flow.

3D digital outcrop model reconstruction of the Kimberley outcrop (Gale crater, Mars) and its integration into Virtual Reality for simulated geological analysis

Structure-from-Motion photogrammetry has recently become a cheap and efficient method to reconstruct accurate and highly-resolved 3D Digital Outcrop Model (DOM) from a single set of images. This enables the 3D visualization of hardly accessible and/or remote geological scenes, which is of strong interest for planetary bodies. This paper focuses on the reconstruction of the DOM of the Kimberley outcrop (Gale crater, Mars) using the Agisoft PhotoScan Professional software. This software is used to compute an accurate, scaled and georeferenced 3D mesh of this outcrop from set of multi-scale images taken by the Mars Science Laboratory rover Curiosity. This model was merged with a 3D model computed from orbital images from the High Resolution Imaging Science Experiment camera (HiRISE) to provide the context. One of the challenges is to integrate data coming from different cameras (with varying optical parameters) not specifically designed for 3D rendering, and with limited points of views. While the obtained DOM allows to observe and characterize geological features of Kimberley’s sedimentary series, classic viewing methods through a 2D screen limits the understanding of the real 3D geometry and scale of the outcrop, as there is no feature such as trees or roads on Mars to provide size references to the user. To overcome this issue and facilitate the interpretation of the DOM, the latter is integrated into a Virtual Reality (VR) environment that enables one or several users working in a collaborative mode to experience a real scale, reliable and realistic depiction of the actual geometries of the geological features reconstructed on the mesh. Precise and accurate description, contextualization of the samplings and mapping of the Kimberley outcrop can therefore be achieved in VR allowing for more precise characterization and interpretations, the same way one would do on a real geological field trip.

Coupled Fan–Stator Aerodynamic and Acoustic Response to Inflow Distortion

Abstract Turbofan rotor–stator aeromechanic and aeroacoustics modeling has been traditionally developed by considering separately the aerodynamic and acoustic response of the fan and the stator to inflow nonuniformities. The present paper develops a model for the coupled fan–stator response for a realistic 3D geometry. The coupling mechanism is assumed to be mainly carried by scattered waves bouncing back and forth between the fan and the stator. The relationship between sources and state elements at three regions (inlet (1), in-between fan and stator (2), and exit (3)) is derived in terms of a scattering matrix S. The model is applied to two fan configurations: (1) a fully subsonic fan and (2) a transonic tip speed fan. The scattering matrix terms, up to the 5th blade passing frequency (BPF), are calculated by using CAAT, an Euler-based code. Results show coupling adds about 6 dB to the sound power level (PWL) of the transonic fan configuration but has a small effect for the subsonic fan configuration. The analysis of the propagating modes shows that, for the transonic configuration, the inlet mode at 1BPF propagates in regions 2 and 3 but is cut off in region 1. This reinforces the coupling process by trapping the acoustic mode 1BPF in region 2. Although this trapped energy is mainly due to the 1BPF of the fan wake, the fan scatters this energy into higher order acoustic modes and thus produces redistribution toward higher frequency of the acoustic spectra. Finally, adding a liner in region 2 reduces the energy of 1BPF mode propagating upstream and impinging on the fan. This mitigates the effect of the fan–stator coupling.

Development of a finite element musculoskeletal model with the ability to predict contractions of three-dimensional muscles

Representation of realistic muscle geometries is needed for systematic biomechanical simulation of musculoskeletal systems. Most of the previous musculoskeletal models are based on multibody dynamics simulation with muscles simplified as one-dimensional (1D) line-segments without accounting for the large muscle attachment areas, spatial fibre alignment within muscles and contact and wrapping between muscles and surrounding tissues. In previous musculoskeletal models with three-dimensional (3D) muscles, contractions of muscles were among the inputs rather than calculated, which hampers the predictive capability of these models. To address these issues, a finite element musculoskeletal model with the ability to predict contractions of 3D muscles was developed. Muscles with realistic 3D geometry, spatial muscle fibre alignment and muscle-muscle and muscle-bone interactions were accounted for. Active contractile stresses of the 3D muscles were determined through an efficient optimization approach based on the measured kinematics of the lower extremity and ground force during gait. This model also provided stresses and strains of muscles and contact mechanics of the muscle-muscle and muscle-bone interactions. The total contact force of the knee predicted by the model corresponded well to the in vivo measurement. Contact and wrapping between muscles and surrounding tissues were evident, demonstrating the need to consider 3D contact models of muscles. This modelling framework serves as the methodological basis for developing musculoskeletal modelling systems in finite element method incorporating 3D deformable contact models of muscles, joints, ligaments and bones.

Effect of Shallow Slip Amplification Uncertainty on Probabilistic Tsunami Hazard Analysis in Subduction Zones: Use of Long-Term Balanced Stochastic Slip Models

The complexity of coseismic slip distributions influences the tsunami hazard posed by local and, to a certain extent, distant tsunami sources. Large slip concentrated in shallow patches was observed in recent tsunamigenic earthquakes, possibly due to dynamic amplification near the free surface, variable frictional conditions or other factors. We propose a method for incorporating enhanced shallow slip for subduction earthquakes while preventing systematic slip excess at shallow depths over one or more seismic cycles. The method uses the classic k−2 stochastic slip distributions, augmented by shallow slip amplification. It is necessary for deep events with lower slip to occur more often than shallow ones with amplified slip to balance the long-term cumulative slip. We evaluate the impact of this approach on tsunami hazard in the central and eastern Mediterranean Sea adopting a realistic 3D geometry for three subduction zones, by using it to model ~ 150,000 earthquakes with M_{w} from 6.0 to 9.0. We combine earthquake rates, depth-dependent slip distributions, tsunami modeling, and epistemic uncertainty through an ensemble modeling technique. We found that the mean hazard curves obtained with our method show enhanced probabilities for larger inundation heights as compared to the curves derived from depth-independent slip distributions. Our approach is completely general and can be applied to any subduction zone in the world.

Microstructure-based finite element model of left ventricle passive inflation

Isolating the role(s) of microstructural pathological features in affecting diastolic filling is important in developing targeted treatments for heart diseases. We developed a microstructure-based constitutive model of the myocardium and implemented it in an efficient open-source finite element modeling framework to simulate passive inflation of the left ventricle (LV) in a representative 3D geometry based on experimentally measured muscle fiber architecture. The constitutive model was calibrated using previous tissue-level biaxial mechanical test data derived from the canine heart and validated with independent sets of measurements made at both the isolated constituent and organ level. Using the validated model, we investigated the load taken up by each tissue constituent and their effects on LV passive inflation. The model predicts that the LV compliance is sensitive to the collagen ultrastructure, specifically, the collagen fiber azimuthal angle with respect to the local muscle fiber direction and its waviness. The model also predicts that most of the load in the sub-epicardial and sub-endocardial regions is taken up, respectively, by the muscle fibers and collagen fiber network. This result suggests that normalizing LV passive stiffness by altering the collagen fiber network and myocyte stiffness is most effective when applied to the sub-endocardial and sub-epicardial regions, respectively. This finding may have implication for the development of new pharmaceutical treatments targeting individual cardiac tissue constituents to normalize LV filling function in heart diseases. Statement of SignificanceCurrent constitutive models describing the tissue mechanical behavior of the myocardium are largely phenomenological. While able to represent the bulk tissue mechanical behavior, these models cannot distinguish the contribution of the tissue constituents and their ultrastructure to heart function. Although microstructure-based constitutive models can be used to isolate the role of tissue ultrastructure, they have not been implemented in a computational framework that can accommodate realistic 3D organ geometry. The present study addresses these issues by developing and validating a microstructure-based computational modeling framework, which is used to investigate the role of tissue constituents and their ultrastructure in affecting heart function.

Physical Mechanisms Create and Loop the Embryonic Heart

The morphogenetic mechanisms that drive heart early development are poorly understood. The objective of this study was to determine the role played by physical forces in formation and looping of the heart tube. The work involved integrating experiments on chick embryos with computational models based on the fundamental laws of mechanics.For decades, it was commonly thought that the bilateral heart fields in the early embryo fold directly toward the midline, where they meet and fuse to form the primitive heart tube. Recent studies have challenged this view, however, suggesting that the heart fields fold in a diagonal pattern that carries their cranial aspects toward the midline. Our experiments and models suggest that differential anisotropic growth between mesoderm and endoderm drives diagonal folding to simultaneously create both the heart tube and foregut. Then, contraction along the anterior intestinal portal generates tension that elongates both structures.After the heart tube forms, it begins to loop to create the basic pattern of the mature heart. During the first phase of looping (c‐looping), the heart tube bends and twists into a c‐shaped tube. First, we created cylindrical finite‐element models to simulate the bending process in isolated hearts. With the number of free parameters reduced as much as possible, numerical distributions of mechanical stress and strain were compared to those measured in cultured chick hearts. The results show that published patterns of hypertrophic growth yield results that agree reasonably well with the trends in our data. Next, we extended our model to include realistic 3D geometry and the effects of external loads, including those exerted by the omphalomesenteric veins at the caudal end of the heart tube and splanchnopleuric membrane against the ventral surface. The bending and torsional behaviors of the model are in reasonable agreement with available experimental data from both control and perturbed embryos, suggesting that a combination of differential growth and external loads drives cardiac c‐looping.Support or Funding InformationThis research was supported by NIH grants R01 GM075200, R01 HL083393, and R01 NS070918.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.