Collaborative Research: SGER: Measuring Forces in Three-Dimensional Granular Materials

*非技术摘要*颗粒材料，如颗粒、雪、沙、煤等，可以像流体一样流动，也可以迅速恢复到固体状态(如在岩石和雪崩中)。对这种致密颗粒物质的认识远远落后于对固体、液体和气体等普通物质的认识。这笔探索性研究的小额赠款支持一个项目，目标是开发一种技术，首次允许研究力如何在静止的三维颗粒状集合中分布的细节。这一成功的结果将有助于解决在处理和处理颗粒材料方面的许多重大实际问题，以及在处理土壤稳定性和滑坡行为方面。同时，对于有能力的研究生来说，这是一个很好的项目，提供了物理、电气和机械设计与施工以及编写软件方面的挑战。*技术摘要*这项探索性研究的小额助学金支持研究型大学和非营利组织的研究人员之间的合作。该项目旨在使用磁共振弹性成像(MRE)来确定全三维颗粒材料中颗粒之间的作用力，这是磁共振成像的一种形式。颗粒材料是当前统计物理学中最大的挑战之一，特别是在颗粒长时间接触的致密相中。力在这些材料中传递的方式具有根本的科学意义。了解这些力量是如何携带的，将为从处理散装工业颗粒物到制药加工的各种技术流程提供信息。尽管已经有广泛的理论发展试图对这种状态进行建模，但目前的实验技术还无法在完全三维的样本中获得粒子之间的力。该项目将首次提供这样的信息，并确定三维颗粒材料中力结构的性质。参与的研究生将学习与物理、电气和机械设计与施工相关的技能，以及编写软件。他们还将接受一个非营利性组织的研究。

*****NON-TECHNICAL ABSTRACT*****Granular materials, such as grains, snow, sand, coal, etc., can flow like fluids or rapidly revert to a solid state (as in a rock and snow avalanches). The understanding of such dense granular matter lags far behind the knowledge of normal matter such as solids, liquids, and gases. This Small Grant for Exploratory Research supports a project with the goal of developing a technique that for the first time should permit the study of the details of how force is distributed in a three dimensional granular assembly at rest. A successful result will contribute significantly to solving many major practical problems in handling and processing granular materials, as well as in dealing with stability of soil and the behavior of landslides. At the same time, this is an excellent project for competent graduate students providing challenges in physics, electrical and mechanical design and construction, and writing software. *****TECHNICAL ABSTRACT*****This Small Grant for Exploratory Research supports a collaboration between researchers at a research university and a not-for-profit organization. The project is directed towards determining forces between grains in fully three-dimensional granular materials using Magnetic Resonance Elastography (MRE), which is a form of Magnetic Resonance Imaging. Granular materials present one of the greatest current challenges in statistical physics, particularly in the dense phases where particles remain in contact for extended periods of time. The way in which forces are carried through these materials is of fundamental interest scientifically. Knowledge of how these forces are carried would inform technical processes ranging from the handling of bulk industrial particulates to pharmaceutical processing. Although there have been extensive theoretical developments that attempt to model this state, current experimental techniques have not been able to access the forces between particles within a fully three-dimensional sample. This project would provide for the first time such information and establish the nature of force structures in 3D granular materials. The graduate students involved will learn skills relevant to physics, electrical and mechanical design and construction, and writing software. They will also be exposed to research at a not-for-profit organization.