Particle resuspension due to mechanical impulse was studied for spherical polymethylmethacrylate (pmma) particles ranging from 1.7 to 14.4 μm in diameter on titanium dioxide (TiO2) and silicon dioxide (SiO2) wafers. Dry powders were dispersed, electrostatically neutralized, and allowed to deposit under the influence of gravity. Contaminated surfaces were then mechanically excited with a 5 MHz piezoelectric transducer where surface accelerations (106 m/s2) and resuspension ratios were quantified with laser Doppler vibrometry (LDV) and digital microscopy, respectively. For TiO2, experiments were performed over a broad range of relative humidity (25 to 95%) to assess the effects of capillary condensation. Resuspension was a monotonically decreasing function of relative humidity. Existing theories were used to separate data into two adhesion regimes based on capillary bridge formation: van der Waals (vdW) and capillary dominated adhesion. For relative humidity above 60%, resuspension forces were nondimensionalized by the theoretical capillary force. Resuspension data for all particle sizes and relative humidity were described by a single sigmoid function dependent on the dimensionless resuspension force. Below 60% relative humidity, resuspension forces were nondimensionalized by the vdW force calculated with Johnson-Kendall-Roberts adhesion theory. The experimental work of adhesion (pmma-TiO2) was optimized such that the dimensionless resuspension curves, for capillary and vdW forces, had equivalent dimensionless resuspension forces at 50% resuspension. The calculated value, 0.047 J/m2, was within the range of values expected from other published works. Resuspension was not observed for particles on SiO2 substrates. This result was attributed to electrostatic surface charge patches where particle charge and surface resistivities were measured to analyze the relative influence of electrostatic adhesion forces.Copyright 2012 American Association for Aerosol ResearchView full textDownload full textRelated var addthis_config = { ui_cobrand: "Taylor & Francis Online", services_compact: "citeulike,netvibes,twitter,technorati,delicious,linkedin,facebook,stumbleupon,digg,google,more", pubid: "ra-4dff56cd6bb1830b" }; Add to shortlist Link Permalink http://dx.doi.org/10.1080/02786826.2012.708464
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机译：研究了由于机械脉冲而导致的颗粒重悬，研究了球形聚甲基丙烯酸甲酯（pmma）颗粒在二氧化钛（TiO 2 ）和二氧化硅（SiO 2 ）晶圆。将干粉分散，静电中和，并使其在重力作用下沉积。然后，用5 MHz压电换能器对受污染的表面进行机械激励，在该传感器中，表面加速度（10 6 m / s 2 ）和再悬浮比通过激光多普勒振动法（LDV）进行定量，并数字显微镜。对于TiO 2 ，在宽范围的相对湿度（25％至95％）上进行了实验，以评估毛细管冷凝的影响。重悬是相对湿度的单调递减函数。现有的理论用于根据毛细管桥的形成将数据分为两种粘附方式：范德华（vdW）和毛细管占主导的粘附。对于高于60％的相对湿度，理论毛细力无法确定悬浮力。所有颗粒尺寸和相对湿度的重悬数据均由一个S型函数描述，具体取决于无量纲的重悬力。相对湿度低于60％时，悬浮力无法通过Johnson-Kendall-Roberts附着力理论计算出的vdW力来确定。优化了附着力（pmma-TiO 2 ）的实验工作，以使毛细管力和vdW力的无量纲重悬曲线在50％重悬力下具有等效的无量纲重悬力。计算值0.047 J / m 2 在其他已发表作品的预期值范围内。在SiO 2 衬底上未观察到颗粒的重悬。该结果归因于静电表面电荷斑块，其中测量了颗粒电荷和表面电阻率以分析静电粘附力的相对影响。版权所有2012美国气溶胶研究协会查看全文下载全文相关变量var addthis_config = {ui_cobrand：“泰勒和弗朗西斯在线” ，services_compact：“ citeulike，netvibes，twitter，technorati，美味，linkedin，facebook，stumbleupon，digg，google，更多”，发布号：“ ra-4dff56cd6bb1830b”}；添加到候选列表链接永久链接http://dx.doi.org/10.1080/02786826.2012.708464
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