Emergent Behaviors of Dense Active Suspensions Under Shear

剪切下致密主动悬架的突现行为

• 批准号: 2327094
• 负责人: Itai Cohen
• 金额: $ 70.91万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2327094&HistoricalAwards=false
• 关键词: Emergent; Behaviors; Dense; Active; Suspensions

Non-Technical AbstractThe flow of dense suspensions comprised of microscopic particles in solution is important to a variety of industrial processes ranging from 3D printing to polishing of semiconductor components. This project seeks to develop a new knob for manipulating the flow of such materials. In particular, it is proposed that particle activity, i.e. using electric fields to inject energy in the form of particle rotations or other motions at the single particle level, can be developed into a novel knob for manipulating the properties of flowing suspensions. The work capitalizes on a novel combination experimental, simulation, and theory techniques developed by the PIs to map out the range of behaviors that activity in flowing suspensions can induce and determine the underlying organization of the suspended particles that drives these changes to the flow. In addition to these technological impacts, a number of education and outreach activities are proposed including science communication workshops, participation in research experience for undergraduate summer activities, and various outreach activities to the broader public.Technical AbstractActive matter has become a major branch of statistical mechanics where energy, rather than being conserved, is pumped into the system at the particle level. One of the great anticipated potentials of synthetic active materials is the ability to tune their macroscopic bulk properties through control of the microscopic interactions governing their constituents. To date, however, most active systems have been limited in their manufacturing scalability making it difficult to investigate bulk properties. This project capitalizes on the development of new Quincke rotor active systems that enable the investigation of the effect of activity on the bulk rheological properties of suspensions. The proposed work focuses on the effects of activity in the dense 3D regime since this is the regime where particles couple most strongly with one another and with the flow. In particular, it aims to determine how activity alters the rheological properties of suspensions including shear thickening and jamming transitions. Specifically, it is proposed to use experiments, simulations, and theory to determine: 1) how activity alters the shear behavior (e.g. thickening) of dense suspensions; 2) how the active particle interactions affect formation of mesoscale load bearing structures, and 3) how the force networks driving these behaviors are organized spatially. These investigations will provide a new knob, activity, for tuning the rheological behaviors of suspensions, an important material system for processes ranging from 3D printing, to polishing in semiconductor processes. In addition to these technological impacts, a number of education and outreach activities are proposed including science communication workshops, participation in research experience for undergraduate activities, and various outreach activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要溶液中由微观颗粒组成的密集悬浮液的流动对于从3D打印到半导体组件抛光的各种工业过程很重要。该项目旨在开发一种新的旋钮来操纵此类材料的流动。特别是，提出粒子活性，即使用电场以粒子旋转的形式注入能量或在单个粒子水平上的其他运动，可以将其发展为一种新型旋钮，以操纵流动悬浮液的特性。 PIS开发的新型组合实验，模拟和理论技术将其资本化，以绘制出流动悬浮液中活动的行为范围，可以诱导和确定将这些变化驱动到流动的悬浮粒子的基本组织。除了这些技术影响外，还提出了许多教育和推广活动，包括科学沟通研讨会，参与本科夏季活动的研究经验以及向更广泛的公众进行各种外展活动。技术抽象的问题已成为统计机制的主要分支，在这些机制中，能源而不是保存的能量，在粒子水平上泵入系统。合成活性材料的巨大预期潜力之一是能够通过控制其成分的微观相互作用来调整其宏观体积特性。但是，迄今为止，大多数活跃系统的制造可伸缩性受到限制，因此很难研究散装特性。该项目利用了新的Quincke转子活性系统的开发，该系统能够研究活动对悬浮液的整体流变特性的影响。提出的工作重点是在密集的3D制度中的活动影响，因为这是粒子彼此最强烈彼此和流动的界面。特别是，它旨在确定活动如何改变悬浮液的流变特性，包括剪切增厚和干扰过渡。具体而言，建议使用实验，仿真和理论来确定：1）活动如何改变致密悬浮液的剪切行为（例如增厚）； 2）活性颗粒相互作用如何影响中尺度负载轴承结构的形成，以及3）如何在空间上组织驱动这些行为的力网络。这些调查将提供一种新的旋钮，用于调整悬浮液的流变行为，这是一个重要的材料系统，用于从3D打印到半导体过程中的抛光。除了这些技术影响外，还提出了许多教育和推广活动，包括科学沟通研讨会，参加本科活动的研究经验以及各种外展活动。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响来通过评估来支持的。