CAREER: Thermal Gradient Microflow Calorimetry using Anisotropic Temperature Sensors

提议的工作将寻求一种独特类型的单向温度传感器的特性和应用。这种传感器的应用将在差示扫描量热法（DSC）领域得到广泛应用。DSC是一门广泛的科学，它研究由温度变化引发的分子间反应中给定物质释放或吸收的能量。这些能量变化通常是在样品随时间稳定加热或冷却时测量的。这种方法天生是一种缓慢的方法，因为在任何时刻，物质内部的温度变化都会给系统带来误差。这个项目将试图改变这种模式。温度梯度本身可以作为分析的中心驱动机制，而不是减速加热使温度梯度无关紧要。通过采用单向温度传感器，快速加热引起的温度变化对能量测量基本上是不可见的，这可以在没有信号失真的情况下实现。这将允许以更快的速度进行高精度DSC，从而揭示分子间反应最难以捉摸的动力学。此外，这种方法将允许为现场采样设计DSC仪器，因为驱动分析的温度梯度自然是由常见事件产生的，例如：将探针插入烤箱或炉子，局部点火或燃烧过程，甚至只是通过管道呼气。它是独特的传感器，将使温度梯度功能，而不是问题。虽然这种提出的分析技术有很多潜在的用途，但它与标准实践有很大的偏差，具有根本不同的热传递行为。因此，围绕其效用的基础科学目前是不完整的。该建议的智力价值涉及到这种新的DSC技术的性能表征。所提出的系统的独特之处在于它将把反应热作为功率而不是能量来检测。该项目将评估这将对热信号的产生、积累、探测和随后的消耗产生的影响。这种提议的DSC方法也具有稳定的传热（称为“等通量”）而不是可忽略的传热（称为“准平衡”）环境的独特特征。这项工作将评估两种情况的相对测量灵敏度，以及每种类型的系统在分析之间返回其基线温度分布的速度。我们还将努力寻找一种优化方案，以进一步提高等通量系统的性能。除了这项工作将对热量学科学界产生直接影响外，这项工作还包含一个教育成分，将服务于多个群体。通过持续的新课程开发、高级设计团队赞助和学生研究机会，将在大学内提供许多新的学习机会。这项工作的范围还包括扩大正在进行的努力，以扩大微流体研究技术的可及性。将开展更多的外联活动，影响代表性不足的人口。一个非常成功的夏令营项目——部分由美国国家科学基金会赞助——将被修改成可移植的形式。教育工作者将能够在整个地区建立这个项目。这将对经济紧张的地区产生特别的影响，在这些地区，参加集中营地计划通常是不现实的。

PI: CrewsCBET-1151148The proposed effort will seek to characterize and apply a unique type of one-directional temperature sensor. The utility of such a sensor will be most felt within the field of differential scanning calorimetry (DSC). DSC is a broad science that examines the energy given off or absorbed by a given substance during intermolecular reactions triggered by temperature change. These energy changes are typically measured while a sample is steadily heated or cooled over time. This approach is innately a slow one, since the presence of temperature variation within the substance at any moment introduces error into the system. This project will seek to change that paradigm. Rather than decelerate heating to make temperature gradients insignificant, temperature gradients themselves can be used as the central driving mechanism of the analysis. This can be achieved without signal distortion by employing a one-directional temperature sensor in a way that the temperature variation caused by rapid heating is essentially invisible to the energy measurement. This will allow for high-precision DSC at faster rates, thereby exposing the most elusive kinetics of the intermolecular reactions. Moreover, this approach will allow for DSC instrumentation to be designed for field sampling, since the temperature gradients driving the analysis naturally result from common events, such as: insertion of a probe into an oven or furnace, a localized ignition or combustion process, or even simply exhaling through a tube. It is the unique sensor that will enable temperature gradients to be functional rather than problematic. Although there is much potential usefulness for this proposed analytical technique, it represents a significant deviation from standard practice, having fundamentally different thermal transport behavior. Therefore, the basic science surrounding its utility is currently incomplete. The intellectual merit of the proposal relates to the performance characterization of this new DSC technique. The proposed system is unique in that it will detect the heat of reaction as power rather than as energy. This project will evaluate the impact this will have on the generation, buildup, detection, and subsequent depletion of heat signatures. This proposed DSC methodology is also uniquely characterized as a steady heat transfer (called "iso-flux") rather than a negligible heat transfer (called "quasi-equilibrium") environment. This work will evaluate the relative measurement sensitivities of both scenarios, as well as the speed with which each type of system will return to its baseline temperature distribution between analyses. Effort will also be made to discover an optimization scheme by which isoflux system performance can be further enhanced.In addition to the direct impact this effort will have on the calorimetric science community, this work contains an educational component that will serve multiple groups. Many new learning opportunities will be made available within the university through a continuation of new course development, senior design team sponsorship, and student research opportunities. The scope of this work also includes an expansion of ongoing efforts to expand the accessibility of microfluidic research technologies. Additional outreach activities will be performed which will impact under-represented populations. A highly successful summer camp program - developed in part through NSF-sponsorship - will be modified into a portable format. Educators will then be able to establish this program across the region. This will have particular impact on the economically-stressed areas, where participation in the centralized camp programs is not generally realistic.