Skip to main content

Michela Geri

Assistant Professor in the Thomas Lord Department of Mechanical Engineering and Materials Science
Thomas Lord Department of Mechanical Engineering and Materials Science

Selected Publications

Interplay between wall slip and shear banding in a thixotropic yield stress fluid.

Journal Article Soft matter · July 2024 We study the local dynamics of a thixotropic yield stress fluid that shows a pronounced non-monotonic flow curve. This mechanically unstable behavior is generally not observable from standard rheometry tests, resulting in a stress plateau that stems from t ... Full text Cite

High-frequency optimally windowed chirp rheometry for rapidly evolving viscoelastic materials: Application to a crosslinking thermoset

Journal Article Journal of Rheology · May 1, 2024 Knowledge of the evolution in the mechanical properties of a curing polymer matrix is of great importance in composite parts or structure fabrication. Conventional rheometry, based on small amplitude oscillatory shear, is limited by long interrogation time ... Full text Cite

Mandelbrot granular raft

Journal Article Physical Review Fluids · November 1, 2023 This paper is associated with a video winner of a 2022 APS/DFD Gallery of Fluid Motion Award for work presented at the DFD Gallery of Fluid Motion. The original video is available online at the Gallery of Fluid Motion, ... Full text Cite

The hidden hierarchical nature of soft particulate gels

Journal Article Nature Physics · August 1, 2023 Soft particulate gels are composed of a small amount of particulate matter dispersed in a continuous fluid phase. The solid components assemble to form a porous matrix, providing rigidity and control of the mechanical response, despite being the minority c ... Full text Cite

Rheo-chemistry of gelation in aiyu (fig) jelly

Journal Article Food Hydrocolloids · February 1, 2022 We investigated the gelation characteristics of aiyu jelly derived from the polymeric extract obtained by washing the seeds of Ficus Pumila var. Awkeotsang. The main gel component is low methoxyl pectin, which forms crosslinks with divalent ions that bind ... Full text Cite

Time-connectivity superposition and the gel/glass duality of weak colloidal gels.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · April 2021 Colloidal gels result from the aggregation of Brownian particles suspended in a solvent. Gelation is induced by attractive interactions between individual particles that drive the formation of clusters, which in turn aggregate to form a space-spanning stru ... Full text Cite

Self-assembly of aramid amphiphiles into ultra-stable nanoribbons and aligned nanoribbon threads.

Journal Article Nature nanotechnology · April 2021 Small-molecule self-assembly is an established route for producing high-surface-area nanostructures with readily customizable chemistries and precise molecular organization. However, these structures are fragile, exhibiting molecular exchange, migration an ... Full text Cite

Medium amplitude parallel superposition (MAPS) rheology. Part 2: Experimental protocols and data analysis

Journal Article Journal of Rheology · September 1, 2020 Featured Publication An experimental protocol is developed to directly measure the new material functions revealed by medium amplitude parallel superposition (MAPS) rheology. This protocol measures the medium amplitude response of a material to a simple shear deformation compo ... Full text Cite

Viscoelastic fishbones

Journal Article Physical Review Fluids · October 24, 2019 This paper is associated with a poster winner of a 2018 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original poster is available from the Gallery of Fluid Motion, ... Full text Cite

Time-Resolved Mechanical Spectroscopy of Soft Materials via Optimally Windowed Chirps

Journal Article Physical Review X · December 6, 2018 Featured Publication The ability to measure the bulk dynamic behavior of soft materials with combined time and frequency resolution is instrumental for improving our fundamental understanding of connections between the microstructural dynamics and the macroscopic mechanical re ... Full text Cite

Computing the linear viscoelastic properties of soft gels using an optimally windowed chirp protocol

Journal Article Journal of Rheology · July 1, 2018 We use molecular dynamics simulations to investigate the linear viscoelastic response of a model three-dimensional particulate gel. The numerical simulations are combined with a novel test protocol (the optimally windowed chirp or OWCh), in which a continu ... Full text Cite

Thermal delay of drop coalescence

Journal Article Journal of Fluid Mechanics · December 25, 2017 Featured Publication We present the results of a combined experimental and theoretical study of drop coalescence in the presence of an initial temperature difference ΔT0 between a drop and a bath of the same liquid. We characterize experimentally the dependence of the residenc ... Full text Cite

Thermokinematic memory and the thixotropic elasto-viscoplasticity of waxy crude oils

Journal Article Journal of Rheology · May 1, 2017 Featured Publication The effect of thermal and shear history on the rheology of waxy crude oils is studied in detail. A protocol sequence is presented, which enables us to systematically extract the main thixotropic features of a model waxy oil by a series of steady state and ... Full text Cite

Cell separation using tilted-angle standing surface acoustic waves.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · September 2014 Separation of cells is a critical process for studying cell properties, disease diagnostics, and therapeutics. Cell sorting by acoustic waves offers a means to separate cells on the basis of their size and physical properties in a label-free, contactless, ... Full text Cite