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1. Accretion–ablation mechanics

   https://doi.org/10.1098/rsta.2022.0373  

   Pradhan, Satya Prakash; Yavari, Arash (December 2023, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences)

   In this paper, we formulate a geometric nonlinear theory of the mechanics of accreting–ablating bodies. This is a generalization of the theory of accretion mechanics of Sozio & Yavari (Sozio & Yavari 2019J. Nonlinear Sci.29, 1813–1863 (doi:10.1007/s00332-019-09531-w)). More specifically, we are interested in large deformation analysis of bodies that undergo a continuous and simultaneous accretion and ablation on their boundaries while under external loads. In this formulation, the natural configuration of an accreting–ablating body is a time-dependent Riemannian $3$-manifold with a metric that is an unknowna prioriand is determined after solving the accretion–ablation initial-boundary-value problem. In addition to the time of attachment map, we introduce a time of detachment map that along with the time of attachment map, and the accretion and ablation velocities, describes the time-dependent reference configuration of the body. The kinematics, material manifold, material metric, constitutive equations and the balance laws are discussed in detail. As a concrete example and application of the geometric theory, we analyse a thick hollow circular cylinder made of an arbitrary incompressible isotropic material that is under a finite time-dependent extension while undergoing continuous ablation on its inner cylinder boundary and accretion on its outer cylinder boundary. The state of deformation and stress during the accretion–ablation process, and the residual stretch and stress after the completion of the accretion–ablation process, are computed. This article is part of the theme issue ‘Foundational issues, analysis and geometry in continuum mechanics’. 

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2. Optimal ablation for interpretability

   Li, Maximilian; Janson, Lucas (September 2024, NeurIPS 2024)
3. Synthesis of Ultrawide Band Gap TeO ₂ Nanoparticles by Pulsed Laser Ablation in Liquids: Top Ablation versus Bottom Ablation

   https://doi.org/10.1021/acsomega.3c10497  

   Subedi, Rajendra; Guisbiers, Grégory (June 2024, ACS Omega)
4. Remote ablation chamber for high efficiency particle transfer in laser ablation electrospray ionization mass spectrometry

   https://doi.org/10.1039/D0AN00984A  

   Dolatmoradi, Marjan; Fincher, Jarod A.; Korte, Andrew R.; Morris, Nicholas J.; Vertes, Akos (August 2020, The Analyst)

   null (Ed.)

   Laser ablation electrospray ionization (LAESI) driven by mid-infrared laser pulses allows the direct analysis of biological tissues with minimal sample preparation. Dedicated remote ablation chambers have been developed to eliminate the need for close proximity between the sample and the mass spectrometer inlet. This also allows for the analysis of large or irregularly shaped objects, and incorporation of additional optics for microscopic imaging. Here we report on the characterization of a newly designed conical inner volume ablation chamber working in transmission geometry, where a reduced zone of stagnation was achieved by tapering the sample platform and the chamber outlet. As a result, the transmission efficiency of both large (>7.5 μm) and smaller particulates (<6.5 μm) has increased significantly. Improved analytical figures of merit, including 300 fmol limit of detection, and three orders of magnitude in dynamic range, were established. Particle residence time, measured by the FWHM of the analyte signal, was reduced from 2.0 s to 0.5 s enabling higher ablation rates and shorter analysis time. A total of six glucosinolates (sinigrin, gluconapin, progoitrin, glucoiberin, glucoraphanin, and glucohirsutin) were detected in plant samples with ion abundances higher by a factor of 2 to 8 for the redesigned ablation chamber. 

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5. Atomic‐Scale Simulations of Meteor Ablation

   https://doi.org/10.1029/2020JA028229  

   Guttormsen, Gabrielle; Fletcher, Alex_C; Oppenheim, Meers_M (September 2020, Journal of Geophysical Research: Space Physics)

   Abstract Meteoroids smaller than a microgram constantly bombard the Earth, depositing material in the mesosphere and lower thermosphere. Meteoroid ablation, the explosive evaporation of meteoroids due to erosive impacts of atmospheric particles, consists of sputtering and thermal ablation. This paper presents the first atomic‐scale modeling of sputtering, the initial stage of ablation where hypersonic collisions between the meteoroid and atmospheric particles cause the direct ejection of atoms from the meteoroid surface. Because meteoroids gain thermal energy from these particle impacts, these interactions are important for thermal ablation as well. In this study, a molecular dynamics simulator calculates the energy distribution of the sputtered particles as a function of the species, velocity, and angle of the incoming atmospheric particles. The sputtering yield generally agrees with semi‐empirical equations at normal incidence but disagrees with the generally accepted angular dependence.Λ, the fraction of energy from a single atmospheric particle impact incorporated into the meteoroid, was found to be less than 1 and dependent on the velocity, angle, atmospheric species, and meteoroid material. Applying this newΛto an ablation model results in a slower meteoroid temperature increase and mass loss rate as a function of altitude. This alteration results in changes in the expected electron line densities and visual magnitudes of meteoroids. Notably, this analysis leads to the prediction that meteoroids will generally ablate 1–4 km lower than previously predicted. This affects analysis of radar and visual measurements, as well as determination of meteoroid mass. 

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