Soot Source Identification by Laser Derivatization (SSILD)

激光衍生化烟灰源识别 (SSILD)

• 批准号: 1236757
• 负责人: Randy Vander Wal
• 金额: $ 34.29万
• 依托单位: Pennsylvania State Univ University Park
• 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: 2012-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1236757&HistoricalAwards=false
• 关键词: Soot; Source; Identification; Laser; Derivatization

1236757Vander WalSoot varies, in physical structure and chemical composition, as dependent upon its source, primarily diesel engines, combustors or power plants. Prior studies have shown the near atomic level structure of soot to be dependent upon the source via quantification of physical structure parameters extracted from HRTEM images. In principle this permits identification of the soot source and its contribution to any particular receptor site. Yet many structural aspects are subtle and the variable chemistry of the particles remains unaddressed. This project will investigate the process of transient laser processing to highlight compositional and structural differences, thereby distinctively and uniquely identifying the source of the soot. The significance of pulsed laser processing is that the material transforms to yield distinctive patterns, dependent upon the combination of initial chemistry and structure. The goal is then to develop the laser-based processing as an analytical tool and identify the process conditions and operational parameters for optimal transformation. Specific objectives directed towards achieving this goal include identifying laser operational parameters, defining dependence upon initial structure and composition, demonstrating differentiation between soot from different sources and quantifying the structural changes statistically.Soot is routinely emitted from heavy-duty trucks, power plants and even jet aircraft such as upon takeoff. Soot is the byproduct of incomplete combustion. Its formation reflects combustion inefficiency and its release imposes health risks and environmental concerns. According to the EPA, soot from anthropogenic sources is responsible for many negative health consequences including asthma, heart arrhythmias and even hospitalizations. New findings show soot may be contributing to climate changes happening near the North Pole, such as accelerating melting of sea ice and snow and changing atmospheric temperatures. Although black carbon is hydrophobic (water hating), chemical and physical changes occurring at its surface can cause it to become hydrophilic (waer loving). Such changes determine soot's contribution to cloud formation, its susceptibility to atmospheric washout and its participation in atmospheric heterogeneous reactions. All such processes significantly impact the atmospheric radiative balance. Recent estimates place black carbon radiative forcing as nearly half that attributed CO2. Therein tracking soot dispersion and source identification is a starting point to address these issues.

1236757Vander WalSoot 的物理结构和化学成分各不相同，具体取决于其来源，主要是柴油发动机、燃烧器或发电厂。先前的研究表明，通过量化从 HRTEM 图像中提取的物理结构参数，烟灰的近原子级结构取决于来源。原则上，这允许识别烟灰源及其对任何特定受体位点的贡献。然而，许多结构方面是微妙的，并且颗粒的可变化学性质仍未得到解决。该项目将研究瞬态激光加工过程，以突出成分和结构差异，从而独特地识别烟灰的来源。脉冲激光加工的重要性在于，材料会转变为产生独特的图案，具体取决于初始化学和结构的组合。然后的目标是开发基于激光的加工作为分析工具，并确定最佳转换的工艺条件和操作参数。实现这一目标的具体目标包括识别激光操作参数、定义对初始结构和成分的依赖性、展示不同来源烟灰的区别以及统计结构变化的量化。烟灰通常从重型卡车、发电厂甚至喷气式飞机中排放飞机，例如起飞时。烟灰是不完全燃烧的副产品。它的形成反映了燃烧效率低下，其释放会带来健康风险和环境问题。据美国环保局称，人为来源的烟尘会造成许多负面健康后果，包括哮喘、心律失常甚至住院。新的发现表明，烟尘可能会导致北极附近发生的气候变化，例如加速海冰和雪的融化以及大气温度的变化。尽管黑碳是疏水性的（憎水），但其表面发生的化学和物理变化会导致其变得亲水（喜水）。这些变化决定了烟尘对云形成的贡献、其对大气冲刷的敏感性以及其参与大气非均质反应。所有这些过程都会显着影响大气辐射平衡。最近的估计表明，黑碳辐射强迫几乎占二氧化碳辐射强迫的一半。其中跟踪烟灰扩散和来源识别是解决这些问题的起点。