RUI: Experimental Investigation of the Physico-chemical Properties of Aqueous Organic and Mixed Organic/Inorganic Systems Important in the Upper Troposphere

我们将研究构成对流层中上层气溶胶粒子的水系统的热力学性质。由于这些气溶胶可能参与卷云的形成，并有助于地球的辐射平衡，因此将研究它们的相图和相对湿度/溶质浓度关系，这取决于它们的相态。利用湿度控制热重分析(HTGA)测量了303-253K范围内几种二元酸的随温度变化的潮解相对湿度(DRH)和浓度/活性关系：丙二酸(C3H4O4)、草酸(C2H2O4)、琥珀酸(C4H6O4)、马来酸(C4H4O4)、苹果酸(C4H6O5)和戊二酸(C5H8O4)。还将研究低温液/固平衡相图。利用差示扫描量热法(DSC)、薄膜红外光谱和高温气相沉积技术(HTGA)测量了二元酸、硫酸铵和水三元体系的相变热、随温度变化的DRH和浓度/活度关系。这项研究的结果将用于验证和约束大气气溶胶模型。本科生将广泛参与实验室实验工作、数据分析和结果交流。将购买一台新的研究级湿度控制热重分析仪(HTGA)，这将加强获得资助机构的研究和教学基础设施。学生将获得丰富的FTIR和DSC仪器以及HTGA的经验。

The thermodynamic properties of aqueous systems that constitute aerosol particles in the mid and upper troposphere will be investigated. Because, depending on their phase, these aerosols may be involved in cirrus cloud formation and contribute to earth's radiation balance, their phase diagrams and relative humidity/solute concentration relationships will be studied. Temperature-dependent deliquescence relative humidity (DRH) and concentration/activity relationships will be measured using humidity-controlled thermogravimetric analysis (HTGA) for several aqueous dicarboxylic acids in the range 303 - 253 K: malonic (C3H4O4), oxalic (C2H2O4), succinic (C4H6O4), maleic (C4H4O4), malic (C4H6O5), and glutaric (C5H8O4). Low temperature liquid/solid equilibrium phase diagrams will also be investigated. Enthalpies of transition, the temperature-dependent DRH, and concentration/activity relationships will be measured using differential scanning calorimetry (DSC), infrared spectroscopy of thin films, and HTGA for ternary systems of dicarboxylic acids, ammonium sulfate, and water.The results of this research will be used to validate and constrain atmospheric aerosol models. Undergraduate students will be extensively involved in laboratory experimental work, data analysis, and communication of results. A new research grade humidity-controlled thermogravimetric analyzer (HTGA) will be purchased, which will enhance the research and teaching infrastructure at the grantee institution. Students will gain extensive experience with FTIR and DSC instruments as well as the HTGA.