CDI-Type II: Collaborative Research: Computational Homology, Jamming, and Force Chains in Dense Granular Flows

摘要领导：0835742非领导：0835571,0835611,0835621PI：C.O？Hern(领导)，R.Behringer，L.Kondic，K.MischaikowCDI-类型II：协作研究：密集颗粒流中的计算同源性、干扰和力链这个项目将采用高度跨学科的方法，集成新的几何技术、建模和实验来解决有关颗粒介质和其他堵塞材料(如玻璃、泡沫和胶体)的物理属性的基本、公开的问题。堵塞材料的特点是它们像固体一样抵抗外力，但像液体一样无序。此外，当施加外力时，许多被阻塞的材料具有被称为力链网络的异质分支结构。虽然力链的存在早在几十年前就已为人所知，但事实证明，对它们在物理过程中的作用的定量理解是难以捉摸的，部分原因是之前的研究无法为它们设计出一个公正和普遍的定义。准确识别和描述力链和堵塞材料对外力的反应可能会在许多领域产生变革性的影响。例如，仅在美国，处理和加工颗粒状材料的财务和能源成本估计就至少达到1万亿美元，这些成本通常效率低下。此外，雪崩和地震都是颗粒介质不可预测的行为对人类造成有害影响的例子。在这项工作中，我们将应用新的数学技术结合计算机模拟和实验来获得对堵塞材料的定量、预测性描述。该项目的外联工作强调向代表人数不足的群体的学生提供教育机会。我们将组织教育和招生旅行，前往东北部以女性为主的文理学院和北卡罗来纳州历史上的黑人学校，如北卡罗来纳州中央大学和东南部的其他学校。这些旅行将包括进行技术和受欢迎的讲座，包括演示，以表明对堵塞材料的研究是有趣和重要的。在与学生的非正式会议中，我们将强调，科学和技术领域的职业是有益的，对那些代表性不足的群体开放。为了进一步激发学生对这项研究的兴趣，我们将举行为期两年两天的实验室开放日，让有前途的本科生能够接触到我们研究的实验和理论方面。为了鼓励堵塞材料领域的研究人员密切合作，我们将举办一年两次的跨学科研讨会。首期研讨会“计算同源工具在颗粒材料中的干扰和流动中的应用”定于2009年冬天举行。

AbstractLead: 0835742 Non-leads: 0835571, 0835611, 0835621PIs: C. O?Hern (Lead), R. Behringer, L. Kondic, K. MischaikowCDI-Type II: Collaborative Research: Computational Homology, Jamming, and Force Chains in Dense Granular FlowsThis project will employ a highly interdisciplinary approach that integrates new geometrical techniques, modeling, and experiments to address fundamental, open questions concerning the physical properties of granular media and other jammed materials such as glasses, foams, and colloids. The hallmark of jammed materials is that they resist applied forces like solids, but are disordered like liquids. In addition, many jammed materials possess heterogeneous, ramified structures known as force chain networks when external forces are applied. Although the existence of force chains has been known for decades, a quantitative understanding of their role in physical processes has proved elusive in part because previous studies have been unable to devise an unbiased and general definition for them. Precise identification and characterization of force chains and the response of jammed materials to applied forces will likely have a transformative impact in many arenas. For example, financial and energy costs of handling and processing of granular materials, typically with high inefficiency, is estimated to be at least one trillion dollars in the US alone. Also, avalanches and earthquakes are examples where the unpredictable behavior of granular media detrimentally impacts mankind. In this work, we will apply novel mathematical techniques coupled with computer simulations and experiments to obtain a quantitative, predictive description of jammed materials. The outreach efforts of this project emphasize providing educational opportunities to students from underrepresented groups. We will organize education and recruiting trips to predominantly female liberal arts colleges in the Northeast and historically black schools in North Carolina, such as North Carolina Central University, and others in the Southeast. These trips will include giving technical and popular lectures, including demonstrations to show that research on jammed materials is intriguing and important. During informal meetings with students we will emphasize that careers in science and technology are rewarding and open to those in underrepresented groups. To stimulate further student interest in this research, we will hold biannual 2-day lab open houses so that promising undergraduates can be exposed to both experimental and theoretical aspects of our research. To encourage close collaboration among researchers in the field of jammed materials, we will organize biannual interdisciplinary workshops. The inaugural workshop, ``Computational Homology Tools Applied to Jamming and Flow in Granular Materials'' is scheduled for the winter of 2009.