Shape Deformation Research Articles

Dynamic Oscillation and Motion of Oil‐in‐Water Emulsion Droplets

AbstractThe interplay of interfacial tensions on droplets results in a range of self‐powered motions that mimic those of living systems and serve as a tunable model to understand their complex non‐equilibrium behavior. Spontaneous shape deformations and oscillations are crucial features observed in nature but difficult to incorporate in synthetic artificial systems. Here, we report sessile oil‐in‐water emulsions that exhibit rapid oscillating behavior. The oscillations depend on the nature and concentration of the surfactant, the chemical composition of the oil, and the wettability of the solid substrate. The rapid changes in the contact angle per oscillation are observed using side‐view optical microscopy. We propose that the changes in the interfacial tension of the oil droplets is due to the partitioning of the surfactant into the oil phase and the movement of self‐emulsified oil out of the parent droplets giving rise to the rhythmic variation in droplet contact‐line. The ability to control and understand droplet oscillation can help model similar oscillations in out‐of‐equilibrium systems in nature and reproduce biomimetic behavior in artificial systems for various applications, such as microfluidic lab‐on‐a‐chip and adaptive materials.

Ab initio calculations for well deformed nuclei: 40Mg and 42Si

We performed ab initio valence-space in-medium similarity renormalization group calculations based on chiral nucleon-nucleon and three-nucleon interactions to study the neutron-rich nuclei around N=28, where the experimental and theoretical evidence point to a rapid transition from spherical to rotational regimes. First, the rotational spectra of 40Mg, 42Si, and 44S are established theoretically, anchored by the calculated E2 transition strength. The results suggest that 40Mg and 42Si exhibit large deformations. After that, the erosion of the N=28 shell closure, especially the evolutions of shape deformation and the emergence of shape coexistence, are discussed in N=28 even-even isotones ranging from 40Mg to 48Ca. Finally, the shell evolution of N=28 in Mg and Si chains is discussed based on the experimental and predicted excitation energies of low-lying states. The results from our ab initio calculations align well with available experimental data, furnishing essential insights into the structure of neutron-rich nuclei, particularly deformations in the vicinity of 40Mg and 42Si.

Deformation behavior of TiB reinforced Ti and Ti6Al4V composite particles under in-situ microcompression

To reveal the role of nano-TiB whiskers in micromechanical behaviors of two common titanium composite particles (TCPs), this paper presents experimental investigation on the elastic and plastic deformation of micron-sized Ti-TiBw and Ti6Al4V-TiBw particles. Scanning electron microscope with in-situ uniaxial compression experiment of single TCP was performed within a diameter range of ∼1–5 μm. This study enables detailed insights into the elastic and plastic deformation and geometrical shape evolution of TiBw reinforced TCPs. It is found that, when the particle size decreases, the flow stress and contact yield stress in microcompression for both TCPs exceed the yield strength of bulk composite pillars with identical content of TiB. The contact yield stress is as high as ∼1.5 GPa and ∼1.3 GPa for the smallest Ti-TiBw (D∼1.45μm) and Ti6Al4V-TiBw (D∼1.78μm) particles measured, respectively. In elastic-plastic and fully plastic regime, the steady plastic flow for both particles can be maintained over ∼2 GPa till the engineering compressive strain of εE ∼ -0.4. Compared with bulk composites, higher strain hardening rate of ∼34.2 and ∼37.5 GPa for Ti-TiBw and Ti6Al4V-TiBw particles demonstrate remarkable pinning capacity induced by nano-TiBw network. No structural damage and microcracks was observed in surface morphology of severely deformed Ti6Al4V-TiBw particles, showing distinctive microscale plasticity. The deformation and strain hardening mechanism for such composite particles have been discussed in terms of grain size, aspect ratio of TiBw and the network architecture.

Enhancing ion mobility spectrometry performance through a programmable ion swarm shaping method based on Bradbury-Nielsen gates

The ion gate is a critical element in drift tube ion mobility spectrometry (IMS) as it directly influences the resolving power and sensitivity of the system. However, the conventional Bradbury-Nielsen gate (BNG) often leads to deformation of the ion swarm shape, resulting in reduced resolving power and significant discrimination effects. To address these limitations, we propose a novel method that incorporates a cutting phase following the gate opening. This approach effectively reduces trailing edge deformation, resulting in a maximum resolving power of over 100 and increased signal intensity. Additionally, this method maintains high resolving power even during longer gate opening times. Remarkably, this method not only significantly reduces the mobility discrimination effect but also enables the achievement of reverse discrimination by adjusting the duration of the cutting phase. Consequently, it demonstrates the potential to selectively amplify the peak height of target ions. Our method offers straightforward implementation across all IMS systems utilizing the BNG, thereby significantly improving system performance.

On-Demand 3D Spatial Distribution of Magnetic Permeability Based on Fe3 O4 Nanoparticle Liquid Toward Micro-Cavity Detectors.

The change of 3D spatial distribution of magnetic permeability can lead to the generation of introduced electrical signals. However, present studies can only achieve rough regulation by simple shape deformation of magnetic elastomers such as compression, bending, or stretching. Accurate control of the 3D spatial distribution of magnetic permeability is still an open question. In this study, an on-demand 3D spatial distribution of magnetic permeability by controlled flowing of Fe3 O4 nanoparticle liquid (FNL) is demonstrated. The flowing routes of FNL are tuned by a 3D-printed cage with pre-designed hollow structure, thus changing the 3D spatial distribution of magnetic permeability. Then, eight symmetrically distributed coils under cage are used to receive characteristic induction voltage signals. Maxwell numerical simulation reveals the working mechanism of signal generation. Notably, those eight coils can detect FNL flowing status in eight directions, allowing recognition of up to 255 different FNL flowing combinations. By introducing machine learning, the micro-cavity detector based on FNL can distinguish nine kinds of micro-cavity structures with an accuracy of 98.77%. This work provides a new strategy for the adjustment of the 3D spatial distribution of the magnetic permeability and expands the application of FNL in the field of space exploration.

Single-cell characterization of deformation and dynamics of mesenchymal stem cells in microfluidic systems: A computational study.

Understanding the homing dynamics of individual mesenchymal stem cells (MSCs) in physiologically relevant microenvironments is crucial for improving the efficacy of MSC-based therapies for therapeutic and targeting purposes. This study investigates the passive homing behavior of individual MSCs in micropores that mimic interendothelial clefts through predictive computational simulations informed by previous microfluidic experiments. Initially, we quantified the size-dependent behavior of MSCs in micropores and elucidated the underlying mechanisms. Subsequently, we analyzed the shape deformation and traversal dynamics of each MSC. In addition, we conducted a systematic investigation to understand how the mechanical properties of MSCs impact their traversal process. We considered geometric and mechanical parameters, such as reduced cell volume, cell-to-nucleus diameter ratio, and cytoskeletal prestress states. Furthermore, we quantified the changes in the MSC traversal process and identified the quantitative limits in their response to variations in micropore length. Taken together, the computational results indicate the complex dynamic behavior of individual MSCs in the confined microflow. This finding offers an objective way to evaluate the homing ability of MSCs in an interendothelial-slit-like microenvironment.

Hygromechanical study of a 16th century painted wooden panel: In-situ experiments to quantify the mechanical effect of the frame and the cradle

In order to prevent damage to painted wooden panels from the cultural heritage sector, curators and conservators must provide the hygroscopic and thermal conditions necessary for their conservation. Furthermore, the design of physical reinforcements such as frames or cradles has to be considered. In this paper, experiments were designed to determine the kinematic response of a painting to hygrometric variations both before and after remedial conservation treatments were undertaken. This study was carried out in the Fabre Museum, Montpellier on the panel painting “La Sainte Trinité couronnant la Vierge” (« The Coronation of the Virgin by the Holy Trinity »), which was placed in a climate-controlled showcase in a museum exhibition space. A glass panel on either side allowed visitors to see both sides of the panel during the experiment. At the same time, two stereoscopic devices allowed us to follow the relief, the shape deformation and surface strain of the panel on its front and back sides. First, the mechanical effect of the frame and cradle was studied. The majority of the deformation was found to be due to the cradle; initially the panel had a complex warp (-5 to 10 mm), decreasing to (-1 to +2 mm) when the cradle was removed. The continuous monitoring (two images per hour) was carrried out to assess the behaviour of the panel during imposed relative humidity (RH) variations of about 13 % RH (between 65 % RH for the maximum and 52 % RH for the minimum) for both the absorption and desorption phases. The global mechanical effect on the curvature was very clear with an opposite direction of deflection between absorption and desorption phases. A comparison of the behaviour of the panel with and without the cradle showed that the change in curvature was about twice as great (4 mm) without the cradle, and its direction moved from an initial slight negative curvature state to a positive one. In terms of strain on both the surfaces, we observed a horizontal shrinkage of about -0.1 % during the desorption phase and a swelling of about +0.1 % during the absorption phase for both the front and back sides of the panel. A further local study allowed us to assess the mechanical phenomenon for each board with the local determination of cupping angles and surface strains. This local study highlighted the change in behaviour of the panel without the cradle. On both sides, the local surface strains were decomposed into the mean strain and the deviation from the mean strain. The study highlighted the fact that the intensity of the mean strain (local swelling or shrinkage due to the hygroscopic changes) was the same for each configuration and was about 0.1 %. Nevertheless, in the case of the panel without the cradle, the imposed variation of relative humidity was smaller (8 % RH instead of 13 % RH), so proportionally the mean strain is higher compared to the case with a cradle. This study over five years has been success in terms of innovative development and multidisciplinary research.

Deformation prediction and shape compensation model of circular channels using laser powder bed fusion

Laser powder bed fusion (L-PBF) technology offers significant advantages, such as lightweight and miniaturized product fabrication and short manufacturing cycles. Circular channels are widely utilized in hydraulic manifold blocks due to their favorable hydrodynamic properties. However, when manufactured using L-PBF, circular channels often exhibit shape deviations caused by residual stresses. In this study, Ti6Al4V (TC4) circular channels with various processing parameters were produced through L-PBF. The influence of scanning speed and laser power on the actual channel profile was investigated. A novel deformation prediction model for circular channels was established based on the Euler–Bernoulli theory. This model accurately predicts deformations resulting from residual stresses during horizontal manufacturing of circular channels using L-PBF, considering the interaction between forces and deformations across different manufactured layers. Furthermore, the model can be employed for channel shape compensation design. The results indicated excellent agreement between the proposed deformation prediction model and the profile of the experimentally manufactured samples. Using the channel shape compensation model for circular channels substantially can reduce the root mean square (RMS) deviation, thereby improving dimensional accuracy.

The Effect of Asynchronous Grouting Pressure Distribution on Ultra-Large-Diameter Shield Tunnel Segmental Response

The complex distribution of synchronous grouting pressure results in excessive tunnel deformation and various structural diseases, especially for ultra-large-diameter shield tunnels. In this study, to reduce the risk of tunnel failure, a three-dimensional refined finite element model was established for the Wuhan Lianghu highway tunnel project, taking into account the non-uniform distribution of synchronous grouting pressure. This study focuses on investigating the development patterns of internal forces, deformations, and damages in segment structures under varying grouting pressure ratios. The results indicate that the primary failure mode of a segment is tensile failure occurring at the outer edge of the arch. Moreover, an increased ratio of grouting pressure between the arch bottom and top leads to a higher positive bending moment value and greater tensile damage at the arch waist. The tunnel ring gradually exhibits distinct “horizontal duck egg” shape deformation. When the grouting pressure ratio is 2.8, there is a risk of tensile cracking at the outer edge of the arch waist. At this time, the segment convergence deformation is 39.71 mm, and the overall floating amount reaches 43.12 mm. This research offers engineering reference for the prediction of internal forces and deformations in ultra-large-diameter shield tunnels during grouting construction, thereby facilitating their application in the development of resilient cities.

A flexible and efficient optimization design framework for the shape of blend-wing-body underwater glider

Shape optimization design plays an important role in improving the gliding performance of blended-wing-body underwater glider (BWBUG), but it faces the challenges of how to handle the geometric constraints and improve the optimization efficiency when building the surrogate-based optimization (SBO) framework. To address these issues, a flexible and efficient optimization design framework for the shape of BWBUG is proposed to perform the shape optimization design of BWBUG. In the framework, an axis-driven geometric free-form deformation method is presented to reduce cost of the BWBUG shape deformation by reasonably controlling the scale of optimization variables, and the rapid calculation method of geometric constraints are derived for the proposed shape deformation method. Based on these, a constrained SBO optimization strategy is developed to directly employ the geometric constraints into the training dataset generation and infill criteria. Finally, the shape of one BWBUG example is optimized, and the results show the flexibility and efficiency of the proposed optimization framework.

Polyline simplification using a region proposal network integrating raster and vector features

ABSTRACT Polyline simplification is crucial for cartography and spatial database management. In recent decades, various rule-based algorithms for vector polyline simplification have been proposed. However, most existing algorithms lack parameter self-adaptive capabilities and require repeated manual parameter adjustments when applied to different polylines. While deep-learning-based methods have recently been introduced for raster polyline image simplification, they cannot achieve end-to-end simplification when the input data and output results are vector polylines. This paper proposes a new deep-learning-based method for vector polyline simplification by integrating both the vector and raster features of the polyline. Specifically, a deep separable convolutional residual neural network was first used to extract the convolutional features of each image. Then, the region proposal network was modified to generate proposal boxes using vector coordinates, and these proposal boxes were used to locate the convolutional feature maps of bends. Finally, convolutional feature maps were fed into a binary classification network to identify unimportant vertices that should be omitted for vector polyline simplification. The experimental results indicated that the proposed method can exploit raster and vector features to achieve automatic and effective polyline simplification without prior map generalization knowledge and manual settings of rules and parameters. The polyline simplification results of the proposed method have a higher compression ratio of coordinate points and lower shape deformation and deviation than the results generated by the classic Wang and Müller (WM) algorithm and Support Vector Machine (SVM) based algorithm, which shows the potential of the proposed method for future applications in map generalization.

Modeling shape deformation of ferrofluid ring section and secondary flow in ferrofluid seals with rectangular polar teeth using BEM and FVM

The focus of this study is on modeling the shape deformation of ferrofluid ring sections and secondary flows in ferrofluid seals with a rectangular polar tooth. These factors determine the sealing capability and homogenization of particles in ferrofluids. The model consists of governing equations for ferrofluid flows, the balance equation of normal stresses on ferrofluid free surfaces, the magnetic field equations and the ferrofluid volume equation. To solve the mathematical model, a method utilizing a combination of boundary element method and finite volume method is proposed. Discretizing the azimuthal velocity equation with boundary element method enables efficient determination of ferrofluid-ring section shape deformation. Furthermore, a discretely fitting method is proposed to solve the issue of lack of analytic expressions for the magnetic field distribution in sealing structures with rectangular polar teeth. Numerical tests of the magnetic field and azimuthal velocity distribution verify the validity and accuracy of the proposed solution method. Numerical experiments conducted on an actual ferrofluid sealing structure show that increasing the rotational speed of the shaft, in conjunction with effect of the centrifugal force, leads to deformation of the ferrofluid-ring section shape and reduces the contact area between the ferrofluid ring and shaft. This results in a decrease in pressure resistance. Typically, at a speed of 10 m/s, the pressure resistance falls by around 20%. The maximum value of secondary-flow velocity is significantly affected by the rotational speed of the shaft, although it does not exceed 0.8% of the linear velocity on the shaft surface in our study.

Modelling of Functional Profiles and Explainable Shape Shifts Detection: An Approach Combining the Notion of the Fréchet Mean with the Shape-Invariant Model

A modelling framework suitable for detecting shape shifts in functional profiles combining the notion of the Fréchet mean and the concept of deformation models is developed and proposed. The generalized mean sense offered by the Fréchet mean notion is employed to capture the typical pattern of the profiles under study, while the concept of deformation models, and in particular of the shape-invariant model, allows for interpretable parameterizations of the profile’s deviations from the typical shape. The EWMA-type control charts compatible with the functional nature of data and the employed deformation model are built and proposed, exploiting certain shape characteristics of the profiles under study with respect to the generalized mean sense, allowing for the identification of potential shifts concerning the shape and/or the deformation process. Potential shifts in the shape deformation process are further distinguished into significant shifts with respect to amplitude and/or the phase of the profile under study. The proposed modeling and shift detection framework is implemented to a real-world case study, where daily concentration profiles concerning air pollutants from an area in the city of Athens are modeled, while profiles indicating hazardous concentration levels are successfully identified in most cases.

Parametric Design and Shape Sensing of Geared Back Frame Shell Structure for Floating Cylindrical Reflector Antenna off the Coast

At present, numerous reflector antennas have been constructed worldwide on land. However, there are few applications of reflector antennas directly set off the coast. To expand the application region of reflector antennas, a floating cylindrical reflector antenna (FCRA) driven by the moving mass was developed to implement the elevation angle adjustment. Firstly, the structure design is introduced in detail. The design parameters are stated and analyzed to obtain the kinematic relationship while considering the water surface constraint. Then, the effects of each variable on the rotation capacity and structural stability are discussed. Further, the feasibility of the elevation angle adjustment process is demonstrated by using a prototype model test and software simulation. Finally, the deformation analyses and shape sensing of the back frame are carried out on the basis of the inverse finite element method (iFEM). We concluded that this new structure is feasible and expected to sit off the coast. In addition, the iFEM algorithm with sub-region reconstruction was proved to be suitable for the shape sensing of the over-constrained FCRA during the angle adjustment process via several quasi-static sampling moments.

The role of the water–air and pulp-froth interfaces on particle detachment: Impact of particle size, type, contact angle and bubble rise velocity

Although the pulp-froth interface is thought to be very important to particle detachment and therefore overall flotation recovery, experimental evidence to back this is contradictory with recent observation indicating that detachment may not be as rigorous as previously thought. We investigate the effect of the interface (air–water and froth-water) on particle detachment as function of particle size, density, hydrophobicity, and bubble sizes. Bubbles were loaded with particles of size classes between 53 µm and 1018 µm and were allowed to collide with the a given interface while videos of the interaction were taken. using a high-speed video camera. The results from the experiments indicate that particles attached to bubbles do not detach when a loaded bubble collides with the interfaces. Further, the particle properties - (size and type of the particles, and contact angle) and bubble had no influence on particle detachment at the interface. However, the particles attached as agglomerates dropped off upon impact and as a result of bubble shape deformations. Further, observations from the water froth interface show that the impact upon collision can significantly shake of particles from within the froth while the particles on the bubble remain attached. Under our experimental conditions, coalescence was also observed not to be as rapid, with loaded bubbles remaining in contact with the water-froth interface for not less than 26 s.

Non-Newtonian pulsatile blood flow through the stenosed arteries: comparison between the viscoelastic and elastic arterial wall in response to the alterations

:In this study, we investigate the impact of aortic stenosis on the hemodynamics of pulsatile blood flow within a 3D aortic model. Employing a non-Newtonian Casson model with a hematocrit of 45%, our study introduces a preliminary hypothesis to simulate blood flow dynamics, incorporating both linear elastic and viscoelastic models to define the mechanical characteristics of the artery. Through simulations conducted with Ansys-Cfx (version 15), we utilize a 2-way fluid-structure interaction (FSI) approach, employing a Lagrangian-Eulerian formulation with second-order accuracy. We explore the influence of stenosis severity on variables including velocity profiles, pressure distribution, shear stress, wall displacement, and changes in the OSI parameter. Our investigation encompasses arteries with both elastic and viscoelastic walls. The key findings that arise from our results highlight the viscoelastic model’s demonstration of reduced radial wall displacement when compared to the linear elastic model. Additionally, we observe that elevated arterial stenosis percentages lead to the elongation of vortex length, heightened wall shear stress, and increased slope of velocity profiles downstream of the stenosed region. Furthermore, bulky obstruction of viscoelastic arteries as opposed to elastic, resulted in a maximum 5 percent increase in velocity profile and a 29.6% decrease in radial displacement. The zenith of shear stress occurs concomitantly with the velocity’s peak within the stenosed area. Viscoelastic arterial wall shear stress at the stenosis site escalates due to the rapid expansion of the stenosis. The viscoelastic wall, responding with a blend of viscous and elastic characteristics to applied stress, undergoes slight deformation in shape. Following stress reduction, the wall gradually reverts to its original form, thus alleviating some of the applied stress. In contrast, the elastic wall retains its altered shape due to stress preservation within the material. Additionally, we ascertain an augmentation in radial displacement corresponding with increased artery stenosis.

Improved calculation of alpha decay half-life by incorporating nuclei deformation shape and proximity potential

Accurate evaluation of alpha decay half-life is essential for understanding nuclear stability, ensuring nuclear safety, optimizing medical treatments, and studying astrophysical processes. Considering the deformed shape of nuclei, we calculated the alpha-decay half-life of 359 nuclei using the proximity potential. In addition, we employed the Wentzel–Kramers–Brillouin approximation to compute the penetration probability through the potential barrier comprising nuclear, Coulomb, and centrifugal potentials. Our calculations revealed that the penetration probability, and hence the alpha-decay half-life, depend on the direction of alpha particle emission relative to the axial symmetry of the nucleus. Furthermore, our results suggested that the dependence of alpha-decay on parent nuclei temperature needs to be reassessed. We tabulated the alpha-decay half-life for various nuclei, and our results showed better agreement with experimental data compared to theoretical data in the literature.

Thermal-structural hybrid Lagrangian solver and numerical simulation-based correction of shape deformation of stainless-steel parts produced by laser powder bed fusion

An efficient thermal-structural numerical solver for Additive Manufacturing has been developed based on a modified Lagrangian approach to solve the energy conservation equations in differential form. The heat transfer is modeled using the finite difference method applied to a deforming Lagrangian mesh. The structural solver has been enhanced with the proposed effective quasi-elastic differential approach for modeling the elastoplastic behavior of materials. The algorithm is relatively simple to implement yet is highly effective. The solver can predict shape deformations of metal parts printed using the laser powder bed fusion technique. The second key capability of the solver is the auto-compensation of distortions of 3D-printed parts by proposing a corrected geometry of a surface to be printed, in order to ensure minimal deviation of the actual printed part from the desired one, even under non-optimal operating conditions or for complex shapes. All the simulation results have been verified in real-life experiments for 3D parts of sizes ranging from 10 to 15 mm up to 40 mm.

Dynamic diselenide bond‐enabled liquid crystal elastomer‐based two‐way shape memory aerogels with weldability and closed‐loop recyclability

AbstractTwo‐way shape memory polymeric aerogels (2W‐SMPAs), with the ability to undergo reversible shape deformation in response to external stimuli, have extensive application in diverse fields such as actuators, sensors, robotics, and other relevant domains. In this study, we introduce a novel approach for fabricating a 2W‐SMPA material based on liquid crystal elastomers (LCEs) incorporating dynamic diselenide bonds. The aerogel exhibits liquid crystal phases, excellent compressibility and shape stability, and the mesogens are uniaxial‐oriented along the stretching direction. By capitalizing on the dynamic diselenide bonds, the LCE‐based aerogel demonstrated remarkable reprogrammability, weldability, and recyclability through thermal reorganization. The shape‐programmed aerogel sample exhibits reversible shrinking deformation during the heating and cooling cycles, ultimately achieving a maximum shrinkage ratio of 26.1%. Moreover, the LCE‐based aerogel's porous structure and monodomain orientation effectively enable the adsorption of the photothermal dye DR1 and facilitated the reversible photothermal‐induced shape deformation when exposed to 520 nm light irradiation. These findings reveal the potential application of this innovative LCE‐based aerogel material, enabled by dynamic diselenide bonds, in various areas including control devices, soft actuators, and other diverse fields.

Stabilities of substitutional solutes in α-iron under uniaxial strain

Nonuniform strain fields in ferritic/martensitic steels working in extreme conditions might induce segregation of alloying solutes. We optimized the structures of iron alloy systems under uniaxial tensile strains along [001] direction within density-functional theory. The calculated segregation energies of solutes Ni, Cu, Al, and Si decrease drastically in a linear fashion as the tensile strain increases up to 17.5%, while those of Co and Ti only change slightly. The segregation energies of solutes V, Nb, Ta, Cr, Mo, and W first decrease and then increase. These results might indicate that, for all solutes studied except Co and Ti, segregation behaviors happen in ferritic/martensitic steels under tensile strains. The shape deformation effect plays a major role in the segregation energies of solutes Cu, Al, Si, Ni, Nb, Ta, Cr, and Mo, while the volumetric effect is dominant for solutes V and W. The segregation energy changes owing to the tensile strain increase from 8% to 14% exhibit a linear relation with the Young modulus changes of the alloys relative to α-iron, which indicates a correlation between the stabilities of solutes and their bonding strength with iron neighbors. The linearly decreasing mixing energies of solutes Mg, Zn and Ga in α-iron with increasing uniaxial strain might suggest a new possible way of fabricating supersaturated iron solid solutions.