Equipment Grant for Interfacial Velocimetry and 3D Liquid-Phase Thermometry in Microfluidic Devices

0933360 Yoda该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。微流控“芯片实验室”通过将分析化学实验室的内容缩小到几平方厘米，改变了各种生化分析。进一步缩小规模，最终在单分子水平上进行测定，需要对界面转运有基本的了解。在这些尺度下，整个流动将在壁的1微米内，表面（例如静电）力变得显著。PI的团队已经率先开发了非侵入式光学技术来研究界面传输，使用基于倏逝波的光学技术，如粒子图像测速法（PIV）和双示踪剂荧光测温法（DFT）来测量400 nm壁内的速度和温度场。最近，他们已经使用多层纳米PIV（MnPIV）来测量速度梯度（即，壁面剪切应力）和滑移长度的关系，并表明在微尺度PIV技术中使用的胶体粒子示踪剂的不均匀分布会显著影响滑移长度的估计。PI的小组还开发了一种DFT技术，可以测量水溶液中的温度场，其空间分辨率小至3微米，灵敏度是以前DFT方法的三倍以上。这一小笔设备赠款将通过支持购买一台可成像40 nm的“下一代”电子倍增CCD相机，（和较小的）示踪剂MnPIV在短暂的曝光所需的最小化布朗效应;和一个旋转盘共焦附件，用于现有的显微镜，以获得三个-“真实的时间”中的三维温度场，由高达70 × 512 × 512个样本组成，空间分辨率小至1.3微米。该设备将支持目前由NSF和海军研究办公室资助的两个亚微米尺度速度和温度测量研究项目。 这些研究项目将通过提高微尺度速度测量技术的准确性和空间分辨率，特别是在近壁区域，并通过首次开发一种温度测量技术来促进对微尺度传输的认识和理解，该技术可以获得三维液相温度场，其空间分辨率足以用于微流体设备。 最后，该设备将支持在全国最大的机械工程项目的研究生和本科生研究人员的教育和（根据2008年的数据）在教育非洲裔美国人和西班牙裔工程师的领导者之一。该奖项是共同资助的TTP计划在CBET。

0933360YodaThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Microfluidic 'Labs on a Chip' have transformed a wide variety of biochemical assays by shrinking the contents of an analytical chemistry laboratory down to a few square centimeters. Scaling down even further, ultimately to assays at the single-molecule level, requires a fundamental understanding of interfacial transport. At these scales, the entire flow will be well within 1 micron of the wall, surface (e.g. electrostatic) forces become significant. The PI's group has led in developing non-intrusive optical techniques to study interfacial transport, using evanescent wave-based optical techniques such as particle image velocimetry (PIV) and dual-tracer fluorescence thermometry (DFT) to measure velocity and temperature fields within 400 nm of the wall. Recently, they have used multilayer nano-PIV (MnPIV) to measure velocity gradient (i.e., wall shear stress) and slip length in Poiseuille flows through hydrophilic and hydrophobically coated microchannels, and shown that the nonuniform distribution of the colloidal particle tracers used in microscale PIV techniques can significantly affect estimates of slip length. The PI's group has also developed a DFT technique that can measure temperature fields in aqueous solutions with a(n in-plane) spatial resolution as small as a 3 micron with a sensitivity more than triple that of previous DFT methods. This small equipment grant will extend the microscale transport diagnostic capabilities of the PI's group by supporting the acquisition of a 'next generation' electron multiplying CCD camera to image 40 nm (and smaller) tracers for MnPIV over the brief exposures required to minimize Brownian effects; and a spinning-disk confocal attachment for an already existing microscope to acquire three-dimensional temperature fields in 'real time' consisting of up to 70 × 512 × 512 samples with a spatial resolution as small as 1.3 micron. This equipment will support two current research projects funded by NSF and the Office of Naval Research for velocity and temperature measurement at sub-micron scales. These research projects will advance knowledge and understanding of microscale transport by improving the accuracy and spatial resolution of microscale velocimetry techniques, especially in the near-wall region, and by developing, for the first time, a thermometry technique that can obtain 3D liquid-phase temperature fields with a spatial resolution fine enough for microfluidic devices. Finally, this equipment will support the education of graduate students and undergraduate researchers at the largest Mechanical Engineering program in the nation and (based on 2008 data) one of the leaders in educating African-American and Hispanic engineers.This award is cofunded with the TTP program in CBET.