https://hdl.handle.net/20.500.14178/908 2026-09-08T10:09:43Z https://hdl.handle.net/20.500.14178/3935 Resource potential of slags from Zambian copper smelters Ettler, Vojtěch; Lichovník, Martin; Mihaljevič, Martin; Kříbek, Bohdan; Nyambe, Imasiku; Ziwa, Gabriel Millions of tonnes of pyrometallurgical slags from copper smelters in the Copperbelt Province and North-Western Province of Zambia have been deposited on dumps near mining and ore processing operations and represent potential sources of valuable elements for the future. Here, we analysed archived and freshly collected copper slag samples (n = 48) from five historical and currently operating Zambian copper smelters to assess their chemical compositions, solid speciation of valuable elements, and resource potential. Elevated values of Cu (mean: 1.43 wt%, up to 9.5 wt %), Co (mean: 4450 mg/kg, up to 2.4 wt%), Ni (mean: 69.2 mg/kg, up to 935 mg/kg) and Mo (mean: 169 mg/kg, up to 422 mg/kg) were detected, predominantly bound in the entrapped matte and metallic droplets. The image analysis of scanning electron micrographs (SEM) was used for the assessment of the size distribution of sulfide/metallic droplets and indicated that copper slags from Nkana (Kitwe) and Mufulira, with the most abundant fraction >100 mu m, are the best candidates for further reprocessing by crushing, milling, and flotation. Nevertheless, slag reprocessing must be carried out in an environmentally friendly way to limit dust generation, which can have implications for the environment (soil systems) and human health. 2026-01-01T00:00:00Z https://hdl.handle.net/20.500.14178/3934 A portable thermo-Raman system for the in-situ analysis of macro-scale mineral samples Mráček, Jan; Tuhý, Marek; Košek, Filip A portable thermo-Raman system (PTRS) for the in-situ analysis of macro-scale materials is presented and evaluated. The system integrates a compact Raman spectrometer with a custom-built resistive heating stage and standoff optics, enabling measurements at working distances of 10-25 cm without the need for optical windows. This design allows for a spatially averaged analysis of heterogeneous bulk samples and facilitates measurements under conditions that are not accessible to conventional laboratory setups. The temperature calibration demonstrated linear heating behavior with deviations within +/- 6 K. The performance of the PTRS was assessed using reference materials (silicon carbide, potassium nitrate) and synthetic hydrated sulfates. The system reliably tracked phase evolution and dehydration processes, with results consistent with laboratory thermo-Raman measurements and literature data. Systematic shifts in the apparent transition temperatures (typically 5-20 degrees C) were observed and are attributed to differences in the heat transfer, sample geometry, and thermal equilibration. The results demonstrate that PTRS provides robust qualitative information on thermally induced phase transformations in bulk materials. Due to its portability and mechanical simplicity, the system represents a promising approach for field-based thermoanalytical investigations of metastable and environmentally sensitive mineral phases. 2026-01-01T00:00:00Z https://hdl.handle.net/20.500.14178/3914 Modeling glacial lake bathymetry and water storage from UAV data in proximity to former Gornersee, Monte Rosa Massif, Western Alps Pandey, Aayushi; Kropáček, Jan Formation and sudden drainage of glacial lakes pose increasing hazards in high-mountain regions, threatening downstream communities, infrastructure and ecosystems. Accurate bathymetric reconstruction and lake volume estimation are crucial for flood modeling, hazard assessment, and monitoring climate-driven glacial lake dynamics. This study uses a recently drained lake at the margin of Gornergletscher, Monte Rosa Massif, Western Alps, to reconstruct its bathymetry and estimate its volume by combining a high-resolution digital elevation model (DEM) from low-cost uncrewed aerial vehicle (UAV) imagery with multispectral Sentinel-2 data. The UAV data were used to generate an orthomosaic and a high-resolution DEM of the empty lake basin. Lake extents corresponding to five filling stages, together with the DEM, enabled pixelwise depth estimation, yielding a mean lake depth for maximal filling of 21.94 m and an estimated corresponding water volume of 0.298 +/- 0.11 & times; 10(6) m3. Field observations indicated direct glacier contact and subglacial drainage through vertical conduits. Sentinel-2 also revealed smaller lakes in 2017 and 2018. Comparative analysis of climate variables from lake (2017, 2018 and 2022) and no-lake (2019-21) years highlighted higher April-June temperatures as the dominant factor controlling lake formation. This study demonstrates the value of integrating UAV three-dimensional (3-D) terrain modeling with satellite remote sensing for high-resolution glacial lake monitoring. 2026-01-01T00:00:00Z https://hdl.handle.net/20.500.14178/3913 Frequency-dependent climate sensitivity of sub-daily radial growth of tree stems at the dry Arctic treeline Tumajer, Jan; Grudd, Hakan; Kuželová, Hana; Lange, Jelena Ana; Treml, Václav Radial growth of tree stems shows remarkable variability over the year but also within individual days. Understanding the frequency-dependent growth sensitivity, i.e., the shifting responses of wood formation to meteorological conditions between annual and daily temporal scales, is essential for predicting forest growth under future climates. However, this knowledge is limited for the cold Arctic margins of species distribution. To address this gap, we monitored intra-annual and sub-daily stem radius variation of Pinus sylvestris L. for 2 years using xylogenesis microsampling and dendrometers at the cold-dry treeline beyond the Arctic Circle near Abisko, Northern Sweden. Using linear statistics, cell growth modeling and wavelet transformation, we separated individual frequencies of stem oscillations, ranked their statistical importance and identified immediate and lagged meteorological drivers of stem radius increment. Radial growth of tree stems showed overlapping oscillations at annual and daily frequencies. On an annual scale, radial growth and cell production peaked during the warm summer months. However, within the summer, stem radius increment accelerated toward the cool, moist midnight hours and ceased during the day as the temperature and solar altitude increased. Accordingly, we identified two growth-optimal intervals with peak growth rates, jointly accounting for 68% of the total growth: (i) an air temperature of 8-16 degrees C with a vapor pressure deficit (VPD) of <0.2 kPa, and (ii) an air temperature of 4-16 degrees C and VPD = 0 kPa. While correlations between peak-summer growth rates and immediate temperature and VPD were negative, these correlations switched to positive when considering lagged meteorological variables preceding growth by up to 4 days. Our results suggest frequency-dependent shifts and lagged responses of radial growth to meteorological variables at the Arctic treeline, particularly for air temperature and humidity. We propose that the midday growth reduction during summer may help explain non-linear responses of northern boreal forests to recent climate warming. 2026-01-01T00:00:00Z