CAREER: Nuclear Magnetic Resonance Microscopy Studies of Microfluidic and Porous Media Transport

abstractcts - 0348076 j。Seymour，蒙大拿州立大学小通道中胶体悬浮液运输的建模与传感器技术的微流体装置混合、医疗植入物感染中微生物细菌的吸附和地球形成生物修复以及用于分离的过滤装置和其他多孔介质有关。这种系统的改进模型可以通过设计医疗传感器和过滤设备以及环境生物修复策略对社会产生广泛的影响。本研究的假设是利用核磁共振显微镜可以表征微通道、毛细管网络和多孔介质中胶体悬浮液流动的非平衡微观结构和动力学。胶体颗粒在100微米通道中的动力学与微流体应用有关，如生物传感器和“芯片实验室”系统，并且是多孔介质中孔隙空间网络中胶体传输的基础。核磁共振显微镜方法允许非侵入性测量时间和长度尺度依赖于不透明系统内的位移，如胶体悬浮液，并为概念和数值模型的测试提供独特的数据。研究将从库埃特几何模型球形胶体颗粒的直线流动开始，然后发展到单毛细血管、毛细血管分叉、毛细血管网络和多孔介质。血液和微生物细菌的细胞悬浮液将在这些相同的流动系统中进行研究，以测试硬球胶体模型与自然系统运输的相关性。本研究的目的是：1)利用核磁共振显微镜方法测量模型和细胞悬浮液在Couette流动中的微观结构、速度分布和扩散张量，对胶体流变学的计算机模型进行测试；2)测量直毛细管微通道中模型和细胞胶体悬浮液的浓度分布、速度和水动力弥散张量；毛细管微通道分叉和网络，以便模拟与微流体和生理流动相关的混合过程，并将目标1中的流变学数据纳入这些模型3)提供浓度分布的首次非侵入性测量；利用核磁共振显微镜流动可视化技术，将微流体装置和多孔介质中的多相输运整合到本科和研究生课程中。这些目标将提供影响胶体流变学的微尺度流体动力学的量化，微流体流动中的混合以及胶体在多孔介质中的运输和沉积。这项工作的意义在于，通过提供其他技术无法获得的不透明胶体分散动力学数据，有可能对现有理论和实验产生新的见解。胶体运输问题在工业、生物医学和环境应用中的普遍存在，校园核磁共振设施DRX250的计算机和数字化升级将使所有用户受益，使该项目对社会产生更广泛的影响。探索核磁共振显微镜在微流控输运中测量非平衡输运系数的下限，这些方法尚未应用，将为宏观系统行为和微尺度动力学的先前数据之间提供关键联系，为微流控中的缩小工程问题提供见解。核磁共振显微镜的流动可视化方面将用于将胶体流变学与微流体混合和多孔介质沉积的概念整合到本科课程中，为泰勒-阿里斯分散等输运现象的核心概念与非确定性混沌混合等高级概念之间提供联系。

AbstractCTS-0348076J. Seymour, Montana State UniversityThe modeling of colloidal suspension transport in small channels is relevant to mixing in microfluidic devices for sensor technology, to the sorption of microbial bacteria in medical implant infections and earth formation bioremediation and to filtration devices and other porous media used for separations. Improved models of such systems could have a broad impact to society through design of medical sensors and filtration devices and environmental bioremediation strategies. The hypothesis of the research is that the nonequilibrium microstructure and dynamics of colloid suspension flows in micro-channels, capillary networks and porous media can be characterized using NMR microscopy. Dynamics of colloidal particles in channels of the order of 100 micrometers are relevant to microfluidic applications such as biosensors and 'lab on a chip' systems and are the basis of colloid transport in the network of pore spaces in porous media. NMR microscopy methods allow noninvasive measurement of time and length scale dependent displacements within opaque systems such as colloidal suspensions and provide unique data for testing of conceptual and numerical models. The research will begin with rectilinear flows of model spherical colloidal particles in a Couette geometry and progress to single capillaries, capillary bifurcations, capillary networks and porous media. Cellular suspensions of blood and microbial bacteria will be studied in these same flow systems to test the relevance of hard sphere colloid models to transport of natural systems.The objectives of the research are:1) To test computer models of colloid rheology by measurement of the microstructure, velocity distribution and diffusion tensor of model and cellular suspensions in Couette flows using NMR microscopy methods2) To measure the concentration distribution, velocity and hydrodynamic dispersion tensor of model and cellular colloid suspension flows in straight capillary microchannels, capillary microchannel bifurcations and networks in order to model mixing processes relevant to microfluidic and physiological flows and incorporate rheological data from objective 1) into such models3) To provide the first non-invasive measurements of concentration distribution, velocity and hydrodynamic dispersion in model and cellular colloidal suspension flows through porous media in order to incorporate microhydrodynamics into models for colloid deposition and transport in porous media4) To integrate multiphase transport in microfluidic devices and porous media into the undergraduate and graduate curricula using NMR microscopy flow visualization.These objectives will provide quantification of the microscale hydrodynamics influencing colloidrheology, mixing in microfluidic flows and colloid transport and deposition in porous media. The significance of this work lies in the potential for new insight into existing theory and experiments by providing data on opaque colloidal dispersion dynamics not available by other techniques.The prevalence of colloid transport issues in industrial, biomedical and environmental applications and the computer and digitizer upgrades of the campus NMR facility DRX250 that will benefit all users, gives the project broader impacts to society.The exploration of the lower resolution limits of NMR microscopy for measurement ofnonequilibrium transport coefficients in microfluidic transport, where these methods have yet to be applied, will provide a key link between prior data on macroscopic system behavior andmicroscale dynamics, lending insight into issues of scale down engineering in microfluidics. The flow visualization aspects of NMR microscopy will be used to integrate concepts from colloidrheology with mixing in microfluidics and deposition in porous media into the undergraduate curricula, providing a connection between core concepts in transport phenomena like Taylor-Aris dispersion and advanced concepts such as non deterministic chaotic mixing.