Experimental Investigations of the Contact Freezing Properties of Mineral Particles Using Optical Tweezers

光镊矿物颗粒接触冷冻特性的实验研究

• 批准号: 1213718
• 负责人: Ryan Sullivan
• 金额: $ 40.83万
• 依托单位: Carnegie-Mellon University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1213718&HistoricalAwards=false
• 关键词: Experimental; Investigations; Contact; Freezing; Properties

The Environmental Chemical Sciences Program in the Chemistry Division at the National Science Foundation supports the research of Professor Ryan Sullivan at Carnegie-Mellon who will determine the contact freezing properties of atmospherically relevant mineral particle compositions using optical tweezers. Professor Sullivan and his students will determine the ability of various types of mineral dust particles to catalyze the spontaneous heterogeneous freezing of supercooled droplets through contact freezing. The droplets will be suspended in a focus laser beam using a refrigerated optical tweezers system. The retrieved Raman spectrum will provide key information on the droplet?s physical and chemical state just prior to and when freezing occurs. The number of dust particle-droplet collisions that occur before freezing will be explicitly known, and contact freezing will also be discriminated from immersion freezing mechanisms. This research will help to resolve long outstanding questions regarding the prevalence of contact freezing in the atmosphere, and its potential importance for modifying cloud properties and inducing precipitation.The proposed research will help fill an important knowledge gap regarding a fundamental phase transition of a ubiquitous molecule in our environment: water. The results will impact a wide range of fields from physical chemistry to biogeochemistry and atmospheric science, and increase our understanding of aerosols-cloud-climate interactions. The findings will be particularly important for improving the outdated descriptions of heterogeneous ice nucleation currently used in weather forecast and global climate models. The project will provide students with valuable experience in the novel use of optical tweezers to study heterogeneous ice nucleation for the first time. Our international collaboration with scientists at the University of Bristol will afford our students with the unique opportunity to be trained by experts in the use of optical tweezers for atmospheric aerosol particle research. The project will provide training opportunities for students in a research area of great societal importance.

美国国家科学基金会化学部的环境化学科学项目支持卡内基梅隆大学的Ryan Sullivan教授的研究，他将使用光学镊子确定与大气相关的矿物颗粒组成的接触冻结特性。沙利文教授和他的学生将通过接触冻结来确定各种类型的矿物粉尘颗粒催化过冷液滴自发非均质冻结的能力。液滴将通过冷冻光镊系统悬浮在聚焦激光束中。检索到的拉曼光谱将提供液滴的关键信息。在冷冻前和冷冻时的物理和化学状态。在冻结之前发生的粉尘颗粒-液滴碰撞次数将被明确地知道，并且接触冻结机制也将与浸入冻结机制区分开来。这项研究将有助于解决长期悬而未决的关于大气中接触冻结的普遍性的问题，以及它对改变云性质和诱导降水的潜在重要性。拟议的研究将有助于填补关于我们环境中普遍存在的分子的基本相变的重要知识空白：水。这些结果将影响从物理化学到生物地球化学和大气科学的广泛领域，并增加我们对气溶胶-云-气候相互作用的理解。这些发现对于改进目前用于天气预报和全球气候模式的非均质冰成核的过时描述将特别重要。本项目将为学生首次使用光学镊子研究非均质冰核提供宝贵的经验。我们与布里斯托尔大学的科学家的国际合作将为我们的学生提供独特的机会，由专家在使用光学镊子进行大气气溶胶粒子研究方面进行培训。该项目将为学生在具有重大社会意义的研究领域提供培训机会。

项目成果

In Situ pH Measurements of Individual Levitated Microdroplets Using Aerosol Optical Tweezers

• DOI: 10.1021/acs.analchem.9b04152
• 发表时间: 2020-01-07
• 期刊: ANALYTICAL CHEMISTRY
• 影响因子: 7.4
• 作者: Boyer, Hallie C.;Gorkowski, Kyle;Sullivan, Ryan C.
• 通讯作者: Sullivan, Ryan C.

Aerosol Optical Tweezers Constrain the Morphology Evolution of Liquid-Liquid Phase-Separated Atmospheric Particles

• DOI: 10.1016/j.chempr.2019.10.018
• 发表时间: 2020-01-09
• 期刊: CHEM
• 影响因子: 23.5
• 作者: Gorkowski, Kyle;Donahue, Neil M.;Sullivan, Ryan C.
• 通讯作者: Sullivan, Ryan C.