Interparticle forces in granular materials are intimately linked to mechanical properties and are known to self-organize into heterogeneous structures, or force chains, under external load. Despite progress in understanding the statistics and spatial distribution of interparticle forces in recent decades, a systematic method for measuring forces in opaque, three-dimensional (3D), frictional, stiff granular media has yet to emerge. In this Letter, we present results from an experiment that combines 3D x-ray diffraction, x-ray tomography, and a numerical force inference technique to quantify interparticle forces and their heterogeneity in an assembly of quartz grains undergoing a one-dimensional compression cycle. Forces exhibit an exponential decay above the mean and partition into strong and weak networks. We find a surprising inverse relationship between macroscopic load and the heterogeneity of interparticle forces, despite the clear emergence of two force chains that span the system.
Readers construct at least 2 interrelated mental representations when they comprehend a text: a textbase and a situation model. Two experiments were conducted with recognition memory to examine how domain knowledge and text coherence influence readers' textbase and situation-model representations. In Experiment 1, participants made remember-know judgments to text ideas. Knowledge and coherence interacted to influence remember judgments differently than know judgments. In Experiment 2, the authors used the process-dissociation procedure to obtain recollection and familiarity estimates. Knowledge and coherence interacted to influence recollection estimates but not familiarity estimates. The authors claim that recollection and familiarity can be used as markers of the different processes involved in constructing a textbase and a situation model.
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