Evolution Of Thickness Research Articles

Operando Optical Imaging of Cathode Swelling Process Inside Lithium Primary Batteries: Comparative Studies between Different Structured CFx.

As a crucial cathode material with ultrahigh theoretical capacity (865 mAh/g) and energy density (>2100 Wh/kg), fluorinated carbon (CFx) is promising for lithium primary batteries. However, the operating performance of CFx cathode is hindered by nonuniform volume expansion during discharging. To investigate this, we used operando confocal microscopy to visualize the thickness evolution of two different CFx cathodes and quantified their swelling ratios as a function of the discharge depth. Our findings show that CFx synthesized from hard carbon (FHC), featuring a disordered structure and abundant pores, exhibits a swelling ratio lower than that of conventional layered fluorinated graphite (FG). This is due to different electrochemical mechanisms: lithium enters FG interlayers nonuniformly through "edge propagation" pathways while lithiation occurs homogeneously in FHC, unraveled by single-particle Raman and photoluminescence measurement. This work enhances our understanding on CFx volume expansion, offering important opportunities to address the cathode swelling issue and optimize electrochemical performance in Li/CFx batteries.

A simulation study on the influence of marginal pinching upon liquid film dynamics

In fluid dynamics, the generation and bursting of surface bubble liquid films in surfactant-laden environments involve complex phenomena, one of which is marginal pinching at the film's foot—a crucial yet inadequately understood aspect due to experimental limitations. Considering its profound impact on liquid film drainage and lifetime, we utilize high-resolution numerical simulations incorporating a weakly compressible scheme and adaptive mesh refinement to dissect the marginal pinching dynamics with unprecedented detail. Our approach elucidates the pinching dynamics and tracks the evolution of film thickness during the critical late-stage drainage process. By leveraging detailed geometric data from pinched regions, we significantly refine existing drainage models, enhancing their predictive accuracy regarding rupture thickness and film lifetime across various viscosities, surfactant concentrations, and bubble sizes. This refined model demonstrates robust alignment with our simulation results. Furthermore, we establish a quantifiable relationship between the prefactor governing reverse flow induced by the Marangoni effect and surfactant concentration. The methodologies and findings of this study provide foundational knowledge that paves the way for optimized industrial processes and an enhanced understanding of natural phenomena.

Nanoscale stress and microstructure gradients across a buckled Mo-Cu bilayer: Cu self-annealing triggered by interface delamination

Residual stresses in thin film structures significantly impact their mechanical properties and affect interface delamination. Highly compressively stressed thin films buckling is the predominant interfacial failure mode due to strain energy release. In the present study the effect of cross-sectional stress and microstructural gradients of thin films on the buckling behavior are explored in a model material system consisting of a thin Cu film sputtered onto glass and a highly compressively stressed 500 nm thick Mo overlayer causing buckling delamination at the Cu-glass interface. Employing synchrotron cross-sectional X-ray nano-diffraction, multiaxial X-ray elastic strain and microstructure distributions were explored across the cross-section of the adhering and buckled bilayer, respectively. In the adhering state, a gradual thickness evolution of columnar microstructure and residual stress was found for Mo, while in Cu, no microstructure changes and only minimal stress variations were detected along the film thickness. After delamination, diffraction peak broadening and changes in unstrained lattice parameters in the Cu sublayer indicated structural defect annihilation and grain coarsening. These microstructural changes were further validated via cross-sectional transmission electron microscopy. The evaluated residual stress distributions across the two sublayers of the pristine and buckled bilayer were used to quantify the released strain energy per unit area due to buckling, amounting to 0.61 J/m². Further cross-validation of experimental stress results with finite element simulations strengthened the experimental findings, providing a comprehensive understanding of the stress distribution across the buckled bilayer.

Evolution of Lubrication Characteristics of Double-Nut Ball Screws Based on an Efficient Surface Roughness Modeling Method

Abstract Accurate prediction of lubrication characteristics, specifically film thickness and pressure distribution, is pivotal for ensuring optimal performance in ball screws. Despite its significance, there is a notable dearth of studies investigating the evolution of lubrication characteristics resulting from the changing surface roughness over prolonged operation of ball screws. Furthermore, obtaining the surface roughness of ball screws poses a challenge due to the limited loading capacity of measurement instruments. Traditional methods involving cutting the screw for surface roughness measurement are impractical for continuous monitoring during extended operation. To address this issue, the present study introduces an efficient approach to model the surface roughness of the raceway in double-nut ball screws. A profilometer is employed to measure profile roughness along two directions (parallel and perpendicular to the rolling direction) without the need to cut the screw raceway. The 2D power spectral densities and height probability densities of profile roughness are calculated to model the surface roughness, and the synthesized data are utilized to solve the Reynolds equation. The simulation method is validated through friction torque tests, demonstrating a calculation accuracy exceeding 92%. The study further explores the evolution of film thickness and pressure distribution in double-nut ball screws during running-in and steady wear stages, revealing severe asperity contact in the two nuts. Additionally, variations in load ratio, friction coefficient, and film thickness ratio (λ) are investigated. Considering the load ratio and λ of the slave nut, it can be inferred that boundary lubrication persists in the two nuts throughout the operation.

Thin Liquid Film View and Shear Stress During the Sliding of Air Bubbles on Tilted Plates.

The challenge when studying the impact and sliding of free-rising air bubbles on tilted surfaces is an experimental limitation in obtaining the film thickness of thin liquid film (TLF) during the bubbles' sliding on tilted surfaces. In this work, spatiotemporal evolution in the film thickness of the moving TLF between a sliding air bubble and a tilted plate was monitored by using a two-wavelength synchronized reflection interferometry microscopy (SRIM) technique. The evolution of the film thickness was directly determined from a timed series of monochromatic interference fringes recorded simultaneously at two different wavelengths. From the film thickness profile, a shear stress map at a given time was determined at different bubble sizes and inclination angles. Results showed that the film thickness of TLFs during the bubbles' sliding on tilted surfaces was in the range of 300-1200 nm, depending on bubble size and tilting angles. Sliding of air bubbles on tilted plates over a thin gap with a few hundred nanometers thickness yielded shear stress in the order of 10-50 Pa. Both the larger bubble size and higher tilting angles yielded a higher shear stress. Experimental results were quantitatively compared to numerical results obtained using the Reynolds lubrication theory. A good match between the two results was achieved. Numerical results suggested that a maximum shear stress exerted on a tilted plate occurred at a 25° tilting angle. This is the first time that the spatiotemporal evolution of TLF during bubbles' sliding on tilted surfaces has been achieved, and the shear stress exerted on the tilted surface has been directly determined.

Probing Surface Dynamics of SiOx Thin-Film Electrodes during Cycling through X-Ray Photoemission Spectroscopy and Operando X-Ray Reflectivity.

SiOx electrodes are promising for high-energy-density lithium-ion batteries (LIBs) due to their ability to mitigate volume expansion-induced degradation. Here, we investigate the surface dynamics of SiOx thin-film electrodes cycled in different carbonate-based electrolytes using a combination of ex situ X-ray photoelectron spectroscopy (XPS) and operando synchrotron X-ray reflectivity analyses. The thin-film geometry allows us to probe the depth-dependent chemical composition and electron density from surface to current collector through the solid electrolyte interphase (SEI), the active material, and the thickness evolution during cycling. Results reveal that SiOx lithiation initiates below 0.4 V vs Li+/Li and indicate a close relationship between SEI formation and SiOx electrode lithiation, likely due to the high resistivity of SiOx. We find similar chemical compositions for the SEI in FEC-containing and FEC-free electrolytes but observe a reduced thickness in the former case. In both cases, the SEI thickness decreases during delithiation due to the removal or dissolution of some carbonate species. These findings give insights into the (de)lithiation of SiOx, in particular, during the formation stage, and the effect of the presence of FEC in the electrolyte on the evolution of the SEI during cycling.

New Method to Recover Activation Energy: Application to Copper Oxidation

The calculation of the activation energy helps to understand and to identify the underlying phenomenon of oxidation. We propose a new method without any a priori hypothesis on the oxidation law, to retrieve the activation energy of partially and totally oxidized samples subject to successive annealing. The method handles the uncertainties on the measurement of metal and oxide thicknesses, at the beginning and at the end of the annealing process. The possible change in oxidation law during annealing is included in the model. By using an adapted Particle Swarm Optimization method to solve the inverse problem, we also calculate the time of final oxidation during the last annealing. We apply the method to successive annealings of three samples with initial nanometric layers of copper, at ambient pressure, in the open air. One, two and three successive laws are recovered from experimental data. We found activation energy values about 105–108 kJ mol−1 at the beginning of the oxidation, 76–87 kJ mol−1 at the second step, and finally 47–59 kJ mol−1 in a third step. We also show that the time evolution of copper and oxide thicknesses can also be retrieved with their uncertainties.

An improved immersed boundary method for turbulent flow simulations on Cartesian grids: extension of a global geometric approach for thin boundary layers and strong flow incidence

This paper presents further improvements to the immersed boundary method introduced in [1]. The proposed developments take place during the pre- and post-processing stages of the simulation workflow and aim to further increase the accuracy of the approach for steady-state simulations of high Reynolds number turbulent flows around aerodynamic geometries facing strong incidence. To this end, the location of the forcing points is further optimized prior to simulation, with an adaptive and local modeling height that accounts for the evolution of the turbulent boundary layer thickness, especially at the leading edge. In addition, the direct extrapolation of the pressure solution at the wall is replaced by first- and second-order reconstructions using the normal pressure gradients interpolated at a new set of image points. This second approach is used only in post-processing, after the simulation, and prevents the degradation of the wall pressure in the presence of strong curvatures or thin boundary layers. These developments have been validated by simulating subsonic turbulent flows around the NACA0012 profile, 2D multi-element airfoil (2DMEA), and HL-CRM half-plane at significant angles of attack. Smooth and accurate skin pressure and friction coefficients are observed, in excellent agreement with body fitted wall-resolved solutions, even for coarser Cartesian meshes. Better drag and lift coefficients calculated by direct near-field integrations are obtained, along with accurate predictions of the near-wall flow physics throughout the turbulent boundary layer.

Pentoxifylline ameliorates subclinical atherosclerosis progression in patients with type 2 diabetes and chronic kidney disease: a randomized pilot trial

BackgroundDiabetic kidney disease (DKD) is associated with a higher risk of cardiovascular disease (CVD). Pentoxifylline (PTF), a nonselective phosphodiesterase inhibitor with anti-inflammatory, antiproliferative, and antifibrotic actions, has demonstrated renal benefits in both clinical trials and meta-analyses. The present work aimed to study the effects of PTF on the progression of subclinical atherosclerosis (SA) in a population of patients with diabetes and moderate to severe chronic kidney disease (CKD).MethodsIn this open-label, randomized controlled, prospective single-center pilot study the evolution of carotid intima-media thickness (CIMT) and ankle-brachial index (ABI) were determined in 102 patients with type 2 diabetes mellitus and CKD assigned to PTF, aspirin or control groups during 18 months. We also determined the variations in the levels of inflammatory markers and Klotho (KL), a protein involved in maintaining cardiovascular health, and their relationship with the progression of SA.ResultsPatients treated with PTF presented a better evolution of CIMT, increased KL mRNA levels in peripheral blood cells (PBCs) and reduced the inflammatory state. The progression of CIMT values was inversely related to variations in KL both in serum and mRNA expression levels in PBCs. Multiple regression analysis demonstrated that PTF treatment and variations in mRNA KL expression in PBCs, together with changes in HDL, were significant determinants for the progression of CIMT (adjusted R2 = 0.24, P < 0.001) independently of traditional risk factors. Moreover, both variables constituted protective factors against a worst progression of CIMT [OR: 0.103 (P = 0.001) and 0.001 (P = 0.005), respectively].ConclusionsPTF reduced SA progression assessed by CIMT variation, a beneficial effect related to KL gene expression in PBCs.Trial registrationThe study protocol code is PTF-AA-TR-2009 and the trial was registered on the European Union Drug Regulating Authorities Clinical Trials (EudraCT #2009–016595–77). The validation date was 2010-03-09.

Tribocorrosion of couplings in seawater environment: An investigation on the positive-negative role of synergy

Tribocorrosion is a recent paradigm of tribology defined as the combination of simultaneous mechanical and chemical wear of couplings. To date, this phenomenon is common in several engineering fields, such as the naval sector where marine equipment, offshore platforms and so on are clear examples. In this regard, the synergy between the mechanical and the chemical effects has a notable effect on the behavior of couplings in seawater environment. Nevertheless, the latter can act also as antagonistic factor. Hence, in this manuscript, an investigation was conducted on a tribosystem composed of an alumina sphere and a stainless-steel AISI 316 L flat, immersed in an artificial seawater solution of 3.8 % NaCl and a pH of 8.2. The analysis, carried out by a reciprocating tribometer equipped with a two/three-electrode potentiostat, was performed for different loads and frequency values, and their correlation with synergistic effects was investigated. The open-circuit potential, friction coefficient, tribocorrosive current and total wear were evaluated for different tribological conditions. It was found that the force and sliding velocity had a significant position in the synergistic response, passing from positive to negative mainly due to the protective action of oxide layer and lubrication behavior of corrosion products formed during the motion. Moreover, the current was modeled via two analytical laws discussed in literature, providing a good agreement with experimental data. Lastly, was provided the oxide thickness evolution formed on the samples surface and its relationship with total wear.

Enhancing Methylated Amorphous Silicon Anode Performances in Li-Ion Batteries By Boron Doping

Methylated amorphous silicon has already demonstrated some advantages as compared to silicon in terms of mechanical properties and cyclability for Li-ion batteries (LIB) [1]. However, the conductivity of methylated amorphous silicon drops by several orders of magnitude when increasing the methyl content in the material, which prevents investigating methyl contents higher than 10%. It is well known that doping significantly improves the conductivity of crystalline or amorphous silicon, and has sometimes been reported to improve the material cyclability when used as a LiB anode [2].Here, boron-doped methylated amorphous silicon electrodes with different methyl contents were investigated as anodes for LiB in half-cell configuration. Boron doped methylated silicon thin films (100nm thick) with various methyl content were cycled in the range 0.025V – 1V at C/2 rate (electrolyte: LP30 with 5%FEC). 10% methylated amorphous silicon with 2% boron doping performs a capacity retention of 77% after 1000 cycles (exhibiting a capacity around 1800 mAh.g-1) of full lithiation/delithiation. Figure 1a shows a clearly improved performance as compared to the undoped material. The stability upon cycling of higher methyl contents (15% and 20%) electrodes is further increased, with a capacity retention exceeding 80% over 1000 cycles of full lithiation/delithiation.The evolution of the SEI thickness can be quantitatively determined from IR spectra during cycling. The thickness in the delithiated state is found to increase from cycle to cycle, but with a lower rate for the doped 10% methylated electrodes (thickness lower than 25 nm after 40 cycles and 30 nm after 80 cycles) than for the undoped ones (thickness larger than 35 nm after 40 cycles), see Figure 1b. The SEI evolution upon cycling for higher methyl content is currently under investigation. Reference [1] L. Touahir, A. Cheriet, D. A. D. Corte, J.-N. Chazalviel, C. H. Villeneuve, F. Ozanam, I. Solomon, A. Keffous, N. Gabouze et M. Rosso, «Methylated silicon: A longer cycle-life material for Li-ion batteries,» Journal of Power Sources, vol. 240, pp. 551-557, 10 2013. [2] M. Salah, C. Hall, P. Murphy, C. Francis, R. Kerr, B. Stoehr, S. Rudd et M. Fabretto, «Doped and reactive silicon thin film anodes for lithium ion batteries: A review,» Journal of Power Sources, vol. 506, p. 230194, 9 2021. Figure 1

Revisiting zircon Eu anomaly as a proxy for crustal thickness: A case study of the Sierra Nevada Batholith

We analyzed detrital zircon from the Sierra Nevada Batholith, western USA, to reassess whether zircon Eu/Eu* can be used to reconstruct crustal thickness in the past. Our reconstruction shows two episodes of crustal thickening between 80–200 Ma in the Sierra Nevada region—one during the Jurassic (170—140 Ma) and the other in the Cretaceous (110—80 Ma). These findings are consistent with the results obtained using the whole-rock La/Yb proxy and observations on crustal deformation. Our results underscore the validity of zircon Eu/Eu* proxy for tracing the evolution of crustal thickness at the batholith or orogen scale, provided that a sufficient number of analyses are obtained. Recent petrologic models questioned the validity of the zircon Eu/Eu* proxy because of the complex interplay among various factors that may affect zircon Eu/Eu*. These models, however, overlooked the interconnections between these factors. In particular, magma redox condition and water content, which are known to significantly impact zircon Eu/Eu*, may also be controlled by differentiation pressure and thus crustal thickness. Therefore, rather than complicating the interpretation, these factors could potentially enhance the pressure control on zircon Eu/Eu*.

Dynamic behaviors of shear-thinning droplet impacting on a spherical particle surface

Non-Newtonian droplet impact is common in nature and industry. The viscosity of non-Newtonian liquids changes with shear stress, leading to different impact behaviors compared to Newtonian liquids. This study prepared shear-thinning solutions by adding HPMC polymer into deionized water and investigated its impact dynamics on hydrophobic spherical surface. The evolution patterns of droplet spreading factor, film thickness, and dynamic contact angle are investigated under different impact conditions. The results show that addition of polymers increases the energy dissipation during impact and suppresses droplet rebound from spherical surface compared to Newtonian droplet with similar viscosity. The droplet-impacting process is distinguished into three phases: (I) initial deformation, (II) inertia-dominated, and (III) viscosity-dominated phases. The temporal evolution of film thickness in Phases I and II is fitted by simple equations. In addition, an empirical formula that integrates Weber and Reynold numbers is proposed to predict the maximum spreading factor of HPMC droplets.

Atomic layer deposition of Al-doped ZnO nanomembrane with in situ monitoring

Due to shortcomings such as poor homogeneity of Al doping, precisely controlling the thickness, inability to conformally deposit on high aspect ratio devices and high pinhole rate, the applications of Al-doped ZnO (AZO) nanomembrane in integrated optoelectronic devices are remarkably influenced. Here, we report in situ monitoring during the atomic layer deposition (ALD) of AZO nanomembrane by using an integrated spectroscopic ellipsometer. AZO nanomembranes with different compositions were deposited with real-time and precise atomic level monitoring of the deposition process. We specifically investigate the half-reaction and thickness evolution during the ALD processes and the influence of the chamber temperature is also disclosed. Structural characterizations demonstrate that the obtained AZO nanomembranes without any post-treatment are uniform, dense and pinhole-free. The transmittances of the nanomembranes in visible range are >94%, and the optimal conductivity can reach up to 1210 S cm−1. The output of current research may pave the way for AZO nanomembrane to become promising in integrated optoelectronic devices.

Analysis of wall thickness evolution and forming quality of sheet metal manufactured by wrinkles-free forming method

Analysis of wall thickness evolution and forming quality of sheet metal manufactured by wrinkles-free forming method

Mechanisms of void nucleation on neat and Glass Syntactic PolyPropylene using in situ synchrotron radiation tomography

The mechanisms of void nucleation of a hollow glass syntactic foam during tensile loading were studied in depth. Flat-notched geometries, cut-out from neat and Glass Syntactic PolyPropylene (GSPP), were investigated by in situ microtomography. Notched specimens with two notch root radii, 4 mm and 0.15 mm named respectively N4 and N0.15, to set initial triaxial stress state in the minimum cross section, were observed. Tomographic data sets, with a resolution of 1.3μm, from stepwise tensile loading, at the SOLEIL synchrotron radiation facilities, were retrieved from the notched zone. In addition, they allowed gathering both the width and thickness evolution in the minimum cross section, and the notch opening displacement during the tests.In line with literature, neat PolyPropylene (PP) showed crazes concentration at the specimen core in N4 specimen, whereas, in N0.15 specimen, they were located at the notch root. In isolated Hollow Glass Microspheres (HGM), mechanisms of crazing and debonding were correspondingly highlighted in the PP matrix and at the poles of HGM. Finally, in GSPP, decohesion follows the same trend as in neat PP, i.e. at the specimen core and near the notch, respectively in N4 and in N0.15 geometry. Scenarios of void nucleation and propagation were outlined. The initiation of the brittle crack in the GSPP is mainly due to the matrix-HGM decohesion followed by the coalescence of near neighbouring caps.

QCT-based spatio-temporal aging atlas of the proximal femur BMD and cortical geometry

Aging is associated with an increased risk of fragility fractures at the hip, resulting from a loss of bone mass. While this loss is typically reported as a decreased mean areal bone mineral density (aBMD) in the proximal femur or the femoral neck, its evolution is spatially inhomogeneous, which might also contribute to the increased risk of fractures. Yet, little is known about the evolution of BMD distribution and cortical thickness with age in the proximal femur. We propose a 3D spatio-temporal atlas of the proximal femur to identify regions with high BMD losses and cortical thinning. The atlas is based on 532 post-mortem QCT scans from donors aged 20 to 94, including 179 female subjects. A point cloud with anatomically corresponding positions was defined for each femur based on a personalized coordinate system. The evolution of BMD and cortical thickness was computed as a multiple linear regression with age and BMI, for female and male subjects separately. The average BMD decrease with age was significant in all subregions for both sexes but higher in females. High BMD losses were observed in the superior and middle neck regions, in the medial part of the head, and in the trochanteric trabecular bone. BMD was well preserved in the inferior neck and, for males, in cortical regions. In both sexes, the cortical thickness decreased significantly in the superior and posterior neck cortex and increased significantly in the inferior neck. Higher BMI was associated with increased BMD in the inferior neck and medial shaft cortex, as well as with increased cortical thickness in all neck and shaft regions for both sexes. The spatio-temporal atlas showed the evolution of BMD distribution and cortical thickness in the proximal femur, with high losses in typical fracture locations, such as the femoral neck and pertrochanteric regions.

Exploring the evolution of mass density and thickness of N-doped Ge-rich GeSbTe during multistep crystallization

Among phase change materials, Ge-rich GeSbTe alloys (GGST) are key alloys for the next generation of embedded phase change memories because of their good thermal stability, allowing their use for the automotive applications. Several studies have investigated GGST crystallization, which takes place in several stages, including phase separation in the amorphous material, the crystallization of the cubic Ge and GST phases before a complete crystallization for higher thermal budget. So far, however, no information is available on the possible changes in density and thickness of such alloys. This paper investigates such variations in density and thickness for a N-doped GGST layer (GGSTN) during isothermal annealing, following the four main stages of its multistep crystallization process. X-ray reflectivity (XRR) and X-ray diffraction were employed for analysis. The study reveals that density and thickness exhibit distinct changes during crystallization, with density increasing by approximately 9% during transition from amorphous to crystalline states. These changes are attributed to alterations in layer morphology, particularly at the Ge crystallization temperature and at the onset of GST crystal formation. Additionally, at high thermal budgets, discrepancies between XRR analysis methods suggest the formation of a thin, lower density layer near the top interface of the GGSTN layer. These results provide insights into the structural evolution of the GGSTN layer, which is crucial for phase change random access memory applications.

Global cloud optical depth daily variability based on DSCOVR/ EPIC observations

When investigating the potential effects of cloud changes on climate, the interday and intraday variabilities should be distinguished. Historically, studies have focused on the long-term cloud changes, and the intraday cycles of cloud properties have been mostly ignored partly owing to the limited availability of global datasets to study higher frequency variabilities. In this regard, DSCOVR’s vantage point at the Lagrange L1 point overcomes the temporal limitations of polar orbiters as well as the limited spatial views of geostationary satellites, allowing characterization of the daytime variability of cloud properties using a single sensor. In previous analyses, we used DSCOVR’s EPIC instrument to characterize the diurnal cycles of cloud height and cloud fraction; here, we expand on previous studies to additionally investigate the variability of cloud optical thickness. We observe a recurring diurnal pattern of cloud optical thicknesses for different latitudinal zones that reaches a maximum around noon regardless of the underlying surface. Once we separate the clouds based on their optical thickness into optically thin (0–3), intermediate (3–10), and thick (10–25), we find that these cloud classes follow different optical thickness diurnal cycles on the global scale. We further explore these differences by combining the evolution of cloud fraction and optical thickness of each group to obtain the diurnal evolution of cloud-fraction-weighted optical depths.

Two-interface and thin-filament approximation in Hele-Shaw channel flow

When a viscous fluid partially fills a Hele-Shaw channel, and is pushed by a pressure difference, the fluid interface is unstable due to the Saffman–Taylor instability. We consider the evolution of a fluid region of finite extent, bounded between two interfaces, in the limit that the interfaces are close, that is, when the fluid region is a thin liquid filament separating two gases of different pressure. In this limit, we derive a second-order ‘thin-filament’ model that describes the normal velocity of the filament centreline, and evolution of the filament thickness, as functions of the thickness, centreline curvature and their derivatives. We show that the second-order terms in this model, that include the effect of transverse flow along the filament, are necessary to regularise the instability. Numerical simulation of the thin-filament model is shown to be in accordance with level-set computations of the complete two-interface model. Solutions ultimately evolve to form a bubble of rapidly increasing radius and decreasing thickness.