Bio-Mediated Technique to Control Phase Changes of Porous Media in Seasonally Frozen Ground

该奖项将开发一种生物中介技术，使用来自嗜冷(嗜寒)微生物的抗冻蛋白(AFP)减少土壤中的冻结和冰晶形成。季节性冻土中的水分在经历冻融循环时会形成大的冰透镜，降低民用基础设施的性能，并影响陆地表面的特征，如辐射平衡和潜热交换。目前，大量的修复工作、化学品和保守的设计方法被用于维护寒冷地区的基础设施，使其处于可使用的状态。我们的解决方案是从嗜冷菌中提取AFP，并使用它们来改变土壤中水的冻结特性，以防止有害冰透镜的形成。这项研究将通过建立一个教育和推广计划来补充，该计划旨在让本科生对复杂工程问题的生物启发解决方案进行趋同研究，并将寒冷地区的生物岩土工程纳入课程。该项目的目标是调查、优化和开发一种生物中介的可持续方法，以控制季节性冻结土壤多孔介质中存在的孔隙水的相变。冰透镜在多孔介质中的生长是一个复杂的热力学过程，它依赖于冻结速率、热提取、热、力和化学力的平衡以及土骨架上的有效应力。我们将研究以下具体目标：(1)表征来自不同嗜冷菌的中到超活性AFP的抗冻性能；(2)调查生物处理土壤的热特征，包括热滞后、相变化、冰点，并评估相应的冰抑制、冰成形和冰重结晶活动；以及(3)评估生物中介技术在冻融循环中的弹性，并调查未经处理和生物处理土壤的强度和变形特征。该项目将推进AFP、冰力学和土-冰界面应用方面的知识库，以提高寒冷地区基础设施的弹性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award will develop a bio-mediated technique to reduce freezing and ice lens formation in soils using antifreeze proteins (AFPs) from psychrophilic (cold-loving) microorganisms. The moisture in the seasonally frozen ground, when subjected to freeze-thaw cycles, can develop large ice lenses that degrade the performance of civil infrastructure and affects land surface characteristics such as radiation balance and latent heat exchange. A significant amount of rehabilitation efforts, chemicals, and conservative design approaches are currently used to maintain cold-region infrastructure in serviceable conditions. Our solution is to extract AFPs from psychrophiles and use them to change the freezing characteristics of water in soil to prevent the formation of the detrimental ice lenses. The research will be complemented by establishing an educational and outreach program to engage undergraduate students in convergence research on bio-inspired solutions to complex engineering problems and incorporate cold-region bio-geotechnics in the curriculum.The goal of this project is to investigate, optimize, and develop a bio-mediated sustainable approach to control the phase change transformations of the pore-water present in the porous media of seasonally frozen ground. The growth of ice-lenses in porous soil media is a complex thermomechanical process that depends on freezing rate, heat extraction, the equilibrium of thermal, mechanical, and chemical forces, and effective stress on soil skeleton. We will investigate the following specific objectives: (1) characterize the antifreeze properties of moderate to hyperactive AFPs from different psychrophiles; (2) investigate the bio-treated soils’ thermal characteristics including thermal hysteresis, phase changes, freezing point and evaluate corresponding ice inhibition, ice shaping, and ice recrystallization activities; and (3) evaluate the resiliency of the bio-mediated technique to freeze-thaw cycles and investigate the strength and deformation characteristics of the untreated and bio-treated soils. This project will advance the knowledge base in applications of AFPs, ice mechanics, and soil-ice interfaces to enhance resiliency of cold region infrastructure.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.