Rheology of nanocrystal-bearing technical and natural silicate melts

纳米尺寸的晶体（也称为纳米晶体）是火山熔体的关键成分。它们对岩浆粘度的影响尚未被理解，因为目前的流变参数化在模拟含纳米颗粒的悬浮液的流变学时必然会失败。因此，该研究项目的目的是通过研究玄武岩和流纹岩熔体的流变学作为浓度，几何形状，表面性质和纳米颗粒团聚程度的函数，获得基本物理过程的基本知识。一个多方法的国家的最先进的分析工具的方法将被用来探索分子和介观结构的含纳米颗粒的悬浮液之前（和之后）的流变测量。该项目将特别关注玻璃熔体中纳米晶的形成，特别是使用重复过冷差示扫描量热法探索液体到固体转化的早期阶段的动力学。结果将被用来提供限制的临界冷却速率和条件下，纳米粒子将形成在过冷的粘性熔体。流变学和动力学数据的结合将是必不可少的进行相关的数值模拟，探索纳米颗粒轴承悬浮液的流体动力学的影响，并提供准确的预测上升岩浆的时间依赖性流变学。

Nano-sized crystals (also called nanolites) are emerging key components of volcanic melts. Their effect on the magma viscosity has not yet been understood as current rheological parameterisations are bound to fail in modelling the rheology of nanoparticle-containing suspensions. The research project aims therefore in gaining basic knowledge of the underlying physical processes by studying the rheology of basaltic and rhyolitic melts as a function of concentration, geometry, surface property and degree of agglomeration of nanoparticles. A multi-method approach of state-of-the-art analytic tools will be used to explore the molecular and mesoscopic structure of nanoparticle-containing suspensions before (and after) the rheometric measurements. The project will pay particular attention to the formation of nanolites in the glass melts by exploring the kinetics of the early stage of the liquid-to-solid transformation using inter alia repetitive supercooling differential scanning calorimetry. Results will be used to provide constraints on the critical cooling rate and the conditions under which nanolites will form in the undercooled viscous melt. The combination of rheometric and kinetic data will be essential to carry out relevant numerical simulations to explore the implications for the fluid dynamics of nanoparticle-bearing suspensions and to offer accurate predictions of the time-dependent rheology of a rising magma.