CAREER: Yield Behavior of Particulate Aggregates and Gels

职业：颗粒聚集体和凝胶的屈服行为

• 批准号: 9876135
• 负责人: Kelly Miller
• 金额: $ 28.27万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2004-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9876135&HistoricalAwards=false
• 关键词: CAREER; Yield; Behavior; Particulate; Aggregates

9876135MillerThe yield properties of gels of aggregated particles are of great economic significance in the ceramics manufacturing, chemical processing, and mining industries, yet remain very poorly understood. Progress has been hampered by the lack of experimental techniques to directly examine the deformation properties of particle aggregates and gels. This Faculty Early CAREER Development project utilizes newly developed digital video microscopy and micromechanical testing techniques to gain a quantitative understanding of the mechanisms, frequencies, and forces required for particles to rearrange during shear and compression. Particulate gel deformation will be observed in-situ to determine the different rearrangement modes which occur, as well as their frequency. Micromechanical testing will directly measure the forces required for particle rearrangement. The micromechanical testing methods have great potential in the study of colloids - with further development, these methods may be able to rival the force resolution of colloidal probe atomic force microscopy. The experiments will be conducted using a variety of model and technically relevant colloids, systematically varying particle size, particle volume fraction, and interparticle potential. It is anticipated that this work will serve as the experimental basis needed to guide the theoretical modeling of particulate gel rheological behavior. Continuing development of undergraduate and graduate level courses will be a major educational goal. Specific projects include the implementation of web-based three dimensional crystal structure models for a structure of materials class, development of a graduate lecture/-laboratory class in ceramics processing, and implementation of new course assessment techniques. Outreach activities will focus upon development of a professional enhancement course for high school science teachers, emphasizing the use of examples from materials science and engineering in standards-based education. The course will be offered in two forms: a lecture/-discussion format to be taught at the Colorado School of Mines, and a web-based distance learning format. It is anticipated that the latter effort will be especially attractive to teachers in rural and disadvantaged areas.The proposed research utilizes new developed digital video microscopy and micromechanical testing techniques to quantitatively examine the deformation modes of particulate gels. The educational component of the plan includes mentoring of freshmen and undergraduate researchers, teaching at all student levels, and course development. The outreach activities are focused upon developing and teaching professional development courses for high school science teachers. The use of visualization techniques to enhance understanding is a theme running throughout the proposed activities.

聚集体颗粒凝胶的产率特性在陶瓷制造、化学加工和采矿工业中具有重要的经济意义，但人们对其了解甚少。由于缺乏直接检测颗粒聚集体和凝胶的变形特性的实验技术，进展受到阻碍。这个学院早期职业发展项目利用新开发的数字视频显微镜和微力学测试技术来定量了解剪切和压缩过程中颗粒重新排列所需的机制、频率和力。将在现场观察颗粒凝胶变形，以确定发生的不同重排模式以及它们的频率。微观力学测试将直接测量粒子重排所需的力。微力学测试方法在胶体研究中具有很大的潜力，随着进一步的发展，这些方法可能能够与胶体探针原子力显微镜的力分辨率相媲美。实验将使用各种模型和技术上相关的胶体，系统地改变颗粒大小，颗粒体积分数和颗粒间势。预计这项工作将作为指导颗粒凝胶流变行为理论建模所需的实验基础。继续发展本科和研究生水平的课程将是一个主要的教育目标。具体项目包括为材料结构课程实施基于网络的三维晶体结构模型，开发陶瓷加工研究生讲座/实验课程，以及实施新的课程评估技术。外联活动将侧重于为高中科学教师开发一门专业提高课程，强调在基于标准的教育中使用材料科学和工程方面的例子。该课程将以两种形式提供：一种是由科罗拉多矿业学院讲授的讲座/讨论形式，另一种是基于网络的远程学习形式。预计后一项努力将特别吸引农村和处境不利地区的教师。提出的研究利用新开发的数字视频显微镜和微力学测试技术来定量检查颗粒凝胶的变形模式。该计划的教育部分包括对新生和本科生研究人员的指导，对所有学生水平的教学以及课程开发。外联活动的重点是为高中科学教师开发和教授专业发展课程。使用可视化技术来增强理解是贯穿整个活动的主题。