Chlorophyll fluorescence is a well-established method to estimate chlorophyll content in leaves. A popular fluorescence-based meter, the Opti-Sciences CCM-300 Chlorophyll Content Meter (CCM-300), ...utilizes the fluorescence ratio F735/F700 and equations derived from experiments using broadleaf species to provide a direct, rapid estimate of chlorophyll content used for many applications. We sought to quantify the performance of the CCM-300 relative to more intensive methods, both across plant functional types and years of use. We linked CCM-300 measurements of broadleaf, conifer, and graminoid samples in 2018 and 2019 to high-performance liquid chromatography (HPLC) and/or spectrophotometric (Spec) analysis of the same leaves. We observed a significant difference between the CCM-300 and HPLC/Spec, but not between HPLC and Spec. In comparison to HPLC, the CCM-300 performed better for broadleaves (r = 0.55, RMSE = 154.76) than conifers (r = 0.52, RMSE = 171.16) and graminoids (r = 0.32, RMSE = 127.12). We observed a slight deterioration in meter performance between years, potentially due to meter calibration. Our results show that the CCM-300 is reliable to demonstrate coarse variations in chlorophyll but may be limited for cross-plant functional type studies and comparisons across years.
Superduplex stainless steel is a widely used material in many industrial areas, due to its significant properties in terms of mechanical and corrosion resistance. In order to guarantee the quality of ...these steels, the ferrite evaluation is an important analysis since many properties depend on the control of the ferrite content. During equipment manufacturing or field inspections, the most conventional way to evaluate the ferrite content is through ferritoscope measurements, due to its portability and easy interpretation. However, it has been observed that the calibration pattern used for ferritoscope calibration can lead to inaccurate ferrite quantification in superduplex inspection. In order to analyze this influence, different characterization techniques were performed in superduplex samples, such as optical microscopy, X-ray diffraction, and vibrating sample magnetometer, to compare with the measurements obtained by a ferritoscope. It was concluded that for high ferrite values, with the calibration made from the calibration pattern provided by the ferritoscope manufacturers, the ferrite values measured showed significant deviations from the real values. The current work presents a solution for using the ferritoscope for a more accurate quantification of the ferrite content in superduplex stainless steels.
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