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Very soft grain assemblies have unique shape-changing capabilities that allow them to be compressed far beyond the rigid jammed state by filling void spaces more effectively. However, accurately following the formation of these systems by monitoring the creation of new contacts, monitoring the changes in grain shape, and measuring grain-scale stresses is challenging. We developed an experimental method that overcomes these challenges and connects their microscale behavior to their macroscopic response. By tracking the local strain energy during compression, we reveal a transition from granular-like to continuous-like material. Mean contact geometry is shown to vary linearly with the packing fraction, which is supported by a mean field approximation. We also validate a theoretical framework which describes the compaction from a local view. Our experimental framework provides insights into the granular micromechanisms and opens perspectives for rheological analysis of highly deformable grain assemblies in various fields ranging from biology to engineering.
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http://dx.doi.org/10.1103/PhysRevE.108.044901 | DOI Listing |
iScience
September 2025
College of Electronic Science and Technology, National University of Defense Technology, Changsha 410073, China.
Monopulse radar angle measurement technology is crucial for modern missile precision guidance systems due to its high accuracy and real-time capabilities. Cross-eye jamming (CEJ) is recognized as one of the most effective countermeasures against monopulse radar. However, traditional CEJ implementation requires complex amplitude and phase modulation through specialized hardware.
View Article and Find Full Text PDFDev Growth Differ
September 2025
Laboratory for Epithelial Morphogenesis, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan.
Multicellular organisms generate organizational complexity through morphogenesis, in which mechanical forces orchestrate the movements and deformations of cells and tissues, while chemical signals regulate the molecular events that generate and coordinate these forces. One common denominator that is critical both for mechanics and biochemistry is material property. Material properties define how materials deform or rearrange under applied forces, and how rapidly molecules interact or spread in space and time.
View Article and Find Full Text PDFPRX Life
February 2025
Department of Physics & Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
When cells in a primary tumor work together to invade into nearby tissue, this can lead to cell dissociations-cancer cells breaking off from the invading front-leading to metastasis. What controls the dissociation of cells and whether they break off singly or in small groups? Can this be determined by cell-cell adhesion or chemotactic cues given to cells? We develop a physical model for this question, based on experiments that mimic aspects of cancer cell invasion using microfluidic devices with microchannels of different widths. Experimentally, most dissociation events ("ruptures") involve single cells breaking off, but we observe some ruptures of large groups (~20 cells) in wider channels.
View Article and Find Full Text PDFACS Biomater Sci Eng
September 2025
Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611-6250, United States.
The development of thick, permeable, three-dimensional (3D) constructs is essential for advancing tissue engineering applications that require efficient mass transport and prolonged cell viability. In this study, a printable gelatin composite-poly(vinyl alcohol) (PVA) bioink is designed and evaluated for the self-supported fabrication of 3D thick porous constructs with satisfactory permeability. The proposed bioink incorporates gelatin solution, gelatin microgels, and PVA, which is utilized as a sacrificial porogen to facilitate postprinting pore formation.
View Article and Find Full Text PDFThis article investigates the SMFTSC for CPS facing jamming attacks and multiple physical faults. An intelligent attacker is capable of emitting interference power and adjusting its strategy by observing the transmitter's sending power, leading to packet dropouts in the controller-to-actuator channel. A Bayesian Stackelberg game is exploited to capture these competitive interactions between the two players, in which the transmitter and the intelligent attacker can only probabilistically obtain information about each other's channel state and transmission cost.
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