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背景相互作用有很强的相关性。 因此，粒度分析是沉积学分析中的一个有力工具，因为物质（例如沉积物、土壤、羽流、气溶胶）粒度的可变性为评估环境中物理特性的性质和历史提供了宝贵的数据。 这些合作研究人员参与了各种沉积学、水文学、古气候学、古湖泊学和生态学研究，其中各种粒度分析方法可用于提供重要的古环境数据。市场上有三种类型的实用粒度分析仪器：沉积仪、激光粒度分析仪和库尔特计数器。 出于下述原因，coulter计数器最符合合作研究者的要求。 沉降仪测量颗粒的动态粒度，可用于区分1-63µm范围内的颗粒。不幸的是，这些仪器对63µm以上的颗粒和占样品5%以下的任何粒度级的分辨率都很差。激光颗粒分析仪通过分析激光束在颗粒周围的前向散射来测量颗粒尺寸。 这些仪器提供了关于30µm以上粒度分布的出色数据，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电解质中颗粒的电荷位移来测量粒度，然后用于确定随后转换为等效球形直径的颗粒体积。 该仪器可以精确地测定1 - 1000µm之间的材料的粒度，因此最适合共同研究者所需的粒度范围和分辨率。 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者的研究要求，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.