Grain size analysis instrument for sedimentological, land use change characterization, paleoclimate, paleolimnological and ecological research

沉积颗粒的大小和比例与颗粒如何与环境环境相互作用有很强的相关性。因此，颗粒分析是沉积学分析的有力工具，因为物质(如沉积物、土壤、羽流、气溶胶)的颗粒大小的变异性为评估环境中物理性质的性质和历史提供了宝贵的数据。合作调查者参与了广泛的沉积学、水文学、古气候、古湖泊和生态研究，其中各种粒度分析方法可用于提供重要的古环境数据。市场上有三种实用的粒度分析仪器；沉降仪、激光颗粒分析仪和库尔特计数器。出于以下概述的原因，库尔特计数器最符合合作研究人员的要求。-沉降仪测量颗粒的动态粒度，在区分1-63微米范围内的颗粒方面很有用。不幸的是，这些仪器对于63微米以上的颗粒和任何大小的样品组成&lt；5%的颗粒分辨率都很低。激光颗粒分析仪通过分析激光在颗粒周围的前向散射来测量颗粒大小。这些仪器提供了关于30微米以上颗粒尺寸分布的出色数据，但严重低估了细粒颗粒的百分比，特别是对于非常细的板状粘土。库尔特计数器通过使用颗粒在电解液中的电荷位移来测量颗粒大小，该仪器可以准确地测定1-1000微米之间材料的粒度，因此最适合合作研究人员所需的大小范围和分辨率。我们建议从Beckman-Coulter购买Multisizer 3 Coulter计数器。该仪器不仅满足研究合作研究人员的研究要求，而且是所获得的仪器报价中最便宜的。

The size and proportions of a sedimentary particle has a strong correlation to how the grain will interact with the environmental setting.  Grain size analysis is thus a powerful tool in sedimentological analysis, as the variability in grain size of a material (e.g. sediment, soil, plume, aerosol) provides invaluable data for assessing the nature and history of physical properties within an environment.  The co-investigators are involved in a wide variety of sedimentological, hydrological, paleoclimate, paleolimnological and ecological research where various grain size analysis methodologies can be utilized to provide important paleoenvironmental data.There are three types of practical grain size analysis instruments on the market; sedigraphs, laser particle analyzers, and coulter counters.  For the reasons outlined below the coulter counter best meets the requirements of the co-investigators.  A sedigraph measures the dynamical grain size of particles and is useful in distinguishing particles in the 1-63µm range. Unfortunately, these instruments have poor resolution for grains above 63µm and for any size fractions comprising < 5% of a sample. Laser particle analyzers measure particle sizes by analyzing the forward scattering of a laser beam around a particle.  These instruments provide excellent data on the distribution of grain sizes above 30µm but severely underestimate the percentage of fine-grained particles, particularly for very fine plate-like clays.  Coulter counters measure grain size by using the charge displacement of a particle in an electrolyte, which is then used to determine a particle volume that is subsequently converted to an equivalent spherical diameter.  This instrument can accurately determine grain size for material between 1 - 1000µm and as such is best suited for the size range and resolution required by the co-investigators.  We propose to purchase the Multisizer 3 Coulter Counter from Beckman-Coulter.  The instrument not only meets the research requirements of the research co-investigators but also was the cheapest of the instrument quotations obtained.