• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Atmospheric Measurement Techniques >Dual-wavelength light-scattering technique for selective detection of volcanic ash particles in the presence of water droplets
【24h】

Dual-wavelength light-scattering technique for selective detection of volcanic ash particles in the presence of water droplets

机译：双波长光散射技术在水滴存在下选择性检测火山灰颗粒

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A new method is presented in this paper which analyses the scattered light of individual aerosol particles simultaneously at two different wavelengths in order to retrieve information on the particle type. We show that dust-like particles, such as volcanic ash, can be unambiguously discriminated from water droplets on a single-particle level. As a future application of this method, the detection of volcanic ash particles should be possible in a humid atmosphere in the presence of cloud droplets. The characteristic behaviour of pure water's refractive index can be used to separate water droplets and dust-like particles which are commonly found in the micrometre size range in the ambient air. The low real part of the water's refractive index around 2700–2800 nm results in low scattered light intensities compared to e.g. the visible wavelength range, and this feature can be used for the desired particle identification. brbr The two-wavelength measurement set-up was theoretically and experimentally tested and studied. Theoretical calculations were done using Mie theory. Comparing the ratio of the scattered light at the two wavelengths (visible-to-IR (infrared), iR/i value) for water droplets and different dust types (basalt, andesite, African mineral dust, sand, volcanic ash, pumice) showed at least 9-times-higher values (on average 70 times) for water droplets than for the dust types at any diameter within the particle size range of 2–20 μm. The envisaged measurement set-up was built up into a laboratory prototype and was tested with different types of aerosols. We generated aerosols from the following powders, simulating dust-like particles: cement dust, ISO 12103-1 A1 Ultrafine Test Dust and ash from the 2012 eruption of the Etna volcano. Our measurements verified the theoretical considerations; the median experimental iR/i value is 8–21 times higher for water than for the "dust" particles.
机译：本文提出了一种新方法，该方法同时分析两个不同波长下的单个气溶胶颗粒的散射光，以检索有关颗粒类型的信息。我们表明，尘埃状颗粒（例如火山灰）可以与水滴在单个颗粒水平上明确区分。作为该方法的未来应用，应该可以在潮湿的环境中在存在云滴的情况下检测火山灰颗粒。纯净水的折射率的特征行为可用于分离通常在环境空气的微米范围内发现的水滴和粉尘状颗粒。相对于例如，水在2700-2800 nm左右的折射率的低实部导致较低的散射光强度。可见波长范围，并且此功能可用于所需的粒子识别。 对两个波长的测量装置进行了理论和实验测试和研究。理论计算是使用米氏理论进行的。比较水滴和不同粉尘类型（玄武岩，安山岩，非洲矿物粉尘，沙子，火山岩）在两个波​​长（可见光（红外）， R ）的散射光的比率在2至20μm的粒径范围内，任何直径的水滴的粉尘值至少比尘埃类型高9倍（平均70倍）。设想的测量设置已建立在实验室原型中，并已使用不同类型的气溶胶进行了测试。我们从以下粉末中生成了气溶胶，模拟了类似粉尘的颗粒：水泥粉尘，ISO 12103-1 A1超细测试粉尘和2012年埃特纳火山爆发时产生的粉尘。我们的测量验证了理论上的考虑;水的实验性 R 中值比“粉尘”颗粒高8-21倍。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号