Object-based classification of mixed forest types in Mongolia

The aim of this study is to produce updated forest map of the Bogdkhan Mountain, Mongolia using multitemporal Sentinel-2A images. The target area has highly mixed forest types and it is very difficult to differentiate the fuzzy boundaries among different forest types. To extract the forest class information, an object-based classification technique is applied and a rule-base to separate the mixed classes is developed. The rule-base uses a hierarchy of rules describing different conditions under which the actual classification has to be performed. To compare the result of the developed method with a result of a pixel-based approach, a Bayesian maximum likelihood classification is applied. The final result indicates overall accuracy of 90.87% for the object-based classification, while for the pixel-based approach it is 79.89%. Overall, the research indicates that the object-based method that uses a thoroughly defined segmentation and a well-constructed rule-base can significantly improve the classification of mixed forest types and produce of a reliable forest map

Selective Precipitation of Th and Rare-Earth Elements from HCl Leach Liquor

In this study, selective precipitation of thorium and rare-earth elements was investigated. The leach liquor contains Th, Ce, La, Nd, Pr, and Sm. Precipitation process was realized by using oxalic acid and selectivity of process was provided with the addition of oxalic acid at different volumes. The concentration of oxalic acid and settling duration were selected as parameters. The pH change of leach liquor was controlled during the experiments. The precipitation order was identified as Th, Sm, Nd and Pr, Ce, and La due to increasing of the oxalic acid volume. The precipitation efficiencies were calculated with remaining metals in leach liquor. The elemental analysis of solutions was realized with Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES), and the phase analysis of the precipitates was realized with X-ray diffractometer (XRD)