Granular Electrification in Aeolian Sand Transport: Paradox or Enigma?

风沙在许多环境中都是一种众所周知的自然灾害。流沙对住区和基础设施构成威胁，增加了粉尘排放，造成一系列人类健康和环境退化问题。人们不太了解的是沙子运输引起的静电的产生。感应电荷可能强到足以增加粉尘的产生，改变沉积物的输送速率；引起输电线路闪络和击穿；或中断信号传输。该项目旨在首次测量自然环境中颗粒电气化的细节，并利用这些数据开发更好的运输模型，以实现电气化。这里的成功有助于理解和预测常见的沉积风成体系（如沙丘场）的演化和迁移。对气候变化影响的预测包括荒漠化加剧和目前稳定的草原（如内布拉斯加州沙丘）的重新恢复。更好的沙流模型将是规划适应以管理未来沙流的宝贵工具。该项目通过建立一个涉及六个国家的国际研究合作网络和培养未来的科学家，包括一名女博士生和几名硕士和本科生，为科学的基础设施做出了贡献。该项目与科学教育中心、大学大气研究公司合作，开发STEM培训教材和视频；与阿拉巴马州运动中的科学计划合作，举办讲习班，培训教师了解地球和空间科学；并提供简单的沙子运输和电气化基础课程示范。该项目将开展全面的实地活动，阐明颗粒电气化对风沙输运速率的影响，并利用结果开发更好的沙输运模型，可应用于当前和未来的地面和地外环境。将获得描述风速的数据；沙子运输;颗粒电荷、大气电荷和表面电荷；跳跃强度;砂粒尺寸和含水率；以及空气温度和相对湿度。数据将用多元回归和其他统计方法进行分析，以量化电气化效应的大小和方向。实验设计将确保得到的数据集具有最高的质量标准，并达到很少（如果有的话）达到的详细程度。成功将导致包括颗粒电气化条件的更强大的输运率模型，从而提高理解沙流、沙丘形成、风蚀和粉尘产生动力学的能力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Wind-blown sand is a well known, natural hazard in many environments. Drifting sand threatens settlements and infrastructure, and enhances dust emissions, with a suite of consequential human health and environmental degradation issues. Less understood is the generation of static electricity caused by sand transport. The induced electric charges may be strong enough to enhance dust generation, alter sediment transport rates; cause flashover and breakdown in transmission lines; or interrupt signal transmission. This project aims to measure, for the first time, details of granular electrification in a natural environment and to use the data to develop better transport models that account for electrification. Success here contributes to understanding and predicting the evolution and migration of common sedimentary aeolian systems such as dune fields. Projections of the impacts of climate change include increased desertification and remobilization of currently stabilized grasslands, such as the Nebraska Sandhills. Better sand transport models will be valuable tools for planning adaptations to manage future sand drift. The project contributes to the infrastructure of science by developing an international research collaboration network involving six countries and training future scientists, including a female Ph.D. student and several M.S. and undergraduate students. The project partners with the Center for Science Education, University Corporation for Atmospheric Research to develop teaching materials and videos for STEM training; work with the Alabama Science in Motion program to conduct workshops for training teachers about Earth and Space science; and deliver simple class demonstrations of fundamentals of sand transport and electrification. This project will conduct a comprehensive field campaign to elucidate the influence of granular electrification on aeolian sand transport rates and use the results to develop better sand transport models that can be applied to current and future terrestrial and extraterrestrial environments. Data will be obtained to describe wind speeds; sand transport; granular, atmospheric, and surficial electrical charges; saltation intensity; sand size and moisture content; and air temperature and relative humidity. The data will be analyzed with multiple regression and other statistical methods to quantify the magnitude and direction of electrification effects. The experimental design will ensure that the resulting data set will be of the highest standards of quality and at a level of detail seldom (if ever) achieved. Success will lead to more robust transport rates models that include granular electrification terms, leading to enhanced ability to understand the dynamics of sand drift, dune building, aeolian abrasion, and dust generation.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.