Interfacial Melting and Frost Heave in Ice

冰中的界面融化和冻胀

• 批准号: 9908945
• 负责人: John Wettlaufer
• 金额: $ 39.93万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-15 至 2003-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9908945&HistoricalAwards=false
• 关键词: Interfacial; Melting; Frost; Heave; Ice

This project is a three-year continuation of a theoretical and experimental study of the dynamics of liquid water existing at the boundaries of ice crystal at temperatures below the freezing point of pure water. This process, called premelting, has significant consequences in the redistributing of brine in sea ice, the apparent migrating of contaminants through glacier ice, and the rate of frost heave and weathering in soils and rocks.Premelting is common to virtually all types of materials, but has been most extensively studied in ice. It can be caused by adsorption forces, wetting, size effects, or substrate disorder, and involves many aspects of surface physics and phase transition phenomena. The study program will include the observing of ice crystal growth from a contaminated solution; of unfrozen water transport between crystals as functions of temperature and temperature differences, as well as such studies between ice crystals and various substrates. An important objective will be the development of useful models for ice growth and impurity transport under natural conditions in order to assess how grain interfaces may serve as chemical conduits. The macroscale consequences of these molecular-scale processes include the evolution of the electromagnetic properties of sea ice which are important in remote sensing, the uptake of chlorine on polar stratospheric cloud particles which are important in the chemistry of ozone destruction, the migration of impurities in ice cores which affect the stratigraphic isochrone estimates, and the penetration of atmospheric pollutants into permafrost and firn.

该项目是对在低于纯水冰点的温度下存在于冰晶边界处的液态水的动力学进行的理论和实验研究的三年延续。 这一过程被称为预融，对海冰中盐水的重新分布、污染物通过冰川冰的明显迁移以及土壤和岩石的冻胀和风化速率都有重要影响。预融几乎常见于所有类型的材料，但在冰中的研究最为广泛。 它可以由吸附力、润湿、尺寸效应或基底无序引起，并且涉及表面物理和相变现象的许多方面。 该研究计划将包括从受污染的溶液中观察冰晶生长;晶体之间的未冻结水传输作为温度和温差的函数，以及冰晶和各种基质之间的研究。 一个重要的目标将是发展有用的模型，在自然条件下的冰的生长和杂质运输，以评估颗粒界面如何可能作为化学管道。这些分子级过程的宏观影响包括：海冰电磁特性的演变，这对遥感十分重要;极地平流层云粒子吸收氯，这对臭氧破坏的化学作用十分重要;冰芯中杂质的迁移，这影响到地层等时线的估计;以及大气污染物渗入永久冻土和积雪。