Connecting Glassy Dynamics to Micro-Scale Elasticity

将玻璃动力学与微尺度弹性联系起来

• 批准号: 1236378
• 负责人: David Pine
• 金额: $ 33万
• 依托单位: New York University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1236378&HistoricalAwards=false
• 关键词: Connecting; Glassy; Dynamics; Micro; Scale

1236378PI: WyartParticulate materials, such as suspensions or granular matter, are the most commonly used materials in industry after water. However, explaining their rheological properties remains a challenge. These systems are complicated by the presence of disorder as well as by structural and dynamical heterogeneities, often on multiple length scales. At high densities, such a granular fluid undergoes a jamming or glass transition where the dynamics stop. In recent years there has been a considerable effort to characterize this transition, and it has been realized that dynamical heterogeneities play a key role. However, there is no consensus concerning what causes such heterogeneities. This project will develop a novel method to measure the micro-scale elasticity of amorphous materials. This approach will be used both experimentally and numerically to characterize the disorder and heterogeneities of amorphous solids, and to investigate the jamming transition by which they are formed. The method consists of introducing probe particles of controlled shapes and sizes. Thermal noise causes the probe particles to rotate on a time scale governed by the elasticity of their local environment, and by their shape and size. Measuring the rotational dynamics of the probe by means of confocal microscopy, light scattering, or numerically in simulations will give access to local elastic properties. The range of time scales and length scales can be tuned by controlling the shape and size of the probes. This method will be employed in colloidal suspensions, both experimentally and numerically, to measure the evolution of elasticity and its spatial heterogeneities as the concentration of colloids is increased, and to test fundamental theories of the glass transition.This project will create an experimental method to probe the microscopic properties of disordered granular materials, the most commonly used materials in industry after water. This method will address questions of fundamental and practical importance in the fields of particle flow, biophysics, soil mechanics, and material science. Insights gained from this study will help improve the design of glassy materials and advance our understanding of clogging or jamming, which are of important for multi-phase flows relevant to the oil industry and potentially for the lethal vaso-occlusive eventt?clogging?occurring in sickle cell disease. In addition to these applications, the subject matter of this project lends itself to educational and community outreach activities.

1236378PI：Wyartparticulate材料（例如悬浮液或颗粒物）是水上工业中最常用的材料。但是，解释他们的流变特性仍然是一个挑战。这些系统的存在以及结构和动态异质性通常在多个长度尺度上变得复杂。在高密度下，这种颗粒状的流体经历了动态停止的干扰或玻璃过渡。近年来，已经做出了相当大的努力来表征这种过渡，并且已经意识到动态异质性起着关键作用。但是，关于导致这种异质性的原因尚无共识。该项目将开发一种新的方法来测量无定形材料的微尺度弹性。这种方法将在实验和数值上使用以表征无定形固体的疾病和异质性，并研究形成它们的干扰过渡。该方法包括引入受控形状和大小的探针颗粒。热噪声会导致探针颗粒在其本地环境的弹性以及其形状和大小的情况下，在时间尺度上旋转。通过共聚焦显微镜，光散射或在模拟中测量探针的旋转动力学将提供访问局部弹性特性。可以通过控制探针的形状和大小来调整时间尺度和长度尺度的范围。随着胶体的浓度的增加，该方法将在实验和数值上使用该方法来测量弹性的演变及其空间异质性，并测试玻璃过渡的基本理论。此项目将创建一种实验方法来探测最常用的材料的无序材料的微观特性，该物质使用了通常的材料。该方法将解决颗粒流，生物物理学，土壤力学和材料科学领域中基本和实际重要性的问题。从这项研究中获得的见解将有助于改善玻璃材料的设计，并提高我们对堵塞或堵塞的理解，这对于与石油工业相关的多相流量很重要，并且可能在镰状细胞疾病中发生致命的血管含量易变的事件。除了这些应用外，该项目的主题还提供了教育和社区外展活动。