Molecular Dynamic Assessment of Carbon Nanotube Drag In Physiologic Conditions

生理条件下碳纳米管阻力的分子动态评估

• 批准号: 8513992
• 负责人: ADRIN GHARAKHANI
• 金额: $ 7.53万
• 依托单位: APPLIED SCIENTIFIC RESEARCH
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-19 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8513992
• 关键词: Accounting; Address; Adoption; Aerosols; Air; Caliber; Carbon Nanotubes; Communities; Computer software; Data; Dependence; Deposition; Development; Drug Formulations; Environmental Health; Exposure to; Fiber; Future; Health; Heart; Human; Humidity; Journals; Length; Link; Liquid substance; Literature; Lung; Measurement; Measures; Mechanics; Modeling; Motion; Nanotubes; Outcome; Particulate; Physiological; Production; Property; Publications; Relative (related person); Research; Respiratory System; Respiratory tract structure; Review Literature; Risk; Series; Shapes; Solid; Toxic effect; Ultrafine; Upper respiratory tract; Water; base; density; experience; exposed human population; fibrogenesis; interest; literature survey; manufacturing process; molecular dynamics; nanomaterials; nanoscale; particle; respiratory; simulation; supercomputer; symposium; tool; ultrafine particle

DESCRIPTION (provided by applicant): The growing ubiquity of carbon nanotubes (CNTs) has raised serious concerns about the potential human health and environmental implications of ultrafine particles in general, and manufactured nanomaterials in particular. To this end, while significant research is conducted to ascertain the material toxicity of nanotubes and their potential, for example, to stimulate pulmonary fibrogenesis, aerosol dynamics simulation tools can serve as a valuable complementary asset to investigate the link between the respiratory flow, the ensuing dynamics of nanotubes in the respiratory tracts, and the eventual deposition of CNTs on the respiratory system walls. A typical outcome of such an analysis would be an estimate of how deep, and at what concentration levels and distributions, CNTs of various sizes and types would penetrate in the respiratory tract under physiologic flow conditions. At the heart of a successful nanotube dynamics simulation lies the availability of accurate models for forces experienced by the nanotube. The dominant forces in the nanometer scale are drag and Brownian motion, where the former is the focus of this proposal. An order of magnitude analysis of the length scales reveals that, depending on the size and orientation of the CNT with respect to the freestream, there may be two flow regimes of relevance to CNT drag - free-molecule and transition. Yet, a review of the literature reveals an absence of drag formulae for nanotubes in these flow regimes. To address this critical and unmet CNT dynamics modeling need, the Specific Aim proposed for this project is to perform a series of Molecular Dynamics simulations of air flow over CNTs under physiologically realistic conditions, and to obtain the drag on the CNT as a function of the relative humidity of the respiratory tract; the flow rate; the inclination angle of the CNT with respect to the streamwise direction; as well as the CNT diameter, chirality, aspect ratio, and end effects. The simulation data will be analyzed and reduced into a drag coefficient function. The results will be presented at an aerosol-related conference and subsequently submitted to (aerosol) journals for publication so as to make the drag coefficient function available to the wider scientific community; thereby, enabling future aerosol dynamics simulations of CNT flow in dry or moist air.

描述（由申请人提供）：碳纳米管（CNTS）的普遍存在引起了人们对超紧身颗粒的潜在人类健康和环境影响的严重关注，尤其是制造的纳米材料。为此，尽管进行了重大研究以确定纳米管的材料毒性及其潜力，例如刺激肺纤维化，但气溶胶动力学模拟工具可以用作有价值的互补资产，以研究呼吸道流动之间的联系，即在呼吸道中随之而来的nanotubes intract syracts wall and contirs and contsostim and Cntsostim os cons of cons oss of cons notifor notifor sy。这种分析的典型结果将是估计在生理流动条件下，在呼吸道中，各种大小和类型的浓度水平和分布的深度和分布都将在呼吸道中渗透。成功的纳米管动力学仿真的核心是纳米管所经历的力的准确模型的可用性。纳米量表中的主要力是阻力和布朗运动，前者是该提议的重点。对长度尺度的数量级分析表明，取决于CNT相对于自由式的大小和方向，可能有两个与CNT拖动的流程度 - 自由分子和过渡。然而，对文献的综述揭示了这些流程度中缺乏纳米管的阻力公式。为了满足这一关键和未完成的CNT动力学建模需求，该项目提出的具体目的是在生理上现实的条件下对CNT上的气流进行一系列分子动力学模拟，并在CNT上获得CNT作为呼吸道相对湿度的函数。流速；倾向 CNT相对于流向方向的角度；以及CNT直径，手性，纵横比和最终影响。模拟数据将进行分析并简化为阻力系数函数。结果将在与气雾相关的会议上提出，随后提交给（气溶胶）期刊以进行出版，以使更广泛的科学界的阻力系数功能可用；从而实现了干燥或潮湿空气中CNT流动的未来气溶胶动力学模拟。