GEOMORPHOLOGICAL CHANGES WITHIN A HILLSLOPE CAUSED BY A WINDTHROW EVENT IN THE TATRA MOUNTAINS,SOUTHERN POLAND

Tree uprooting plays an important role in hillslope evolution. The geomorphological impact of tree uprooting after a foehn wind occurrence, in December 2013 in the Tatra Mountains, was investigated. Geomorphological mapping was conducted in three watersheds. Additionally, in one of the watersheds, 459 windthrow pits were measured, in an area of 6.4 ha. The mean volume of a pit was 2.41 m³, and the mean surface area was 5.47 m². 3.9% of the area was affected by windthrow pits, however locally the magnitude of changes was significantly higher, reaching up to 14.5% of the surface area. Slope inclination weakly influenced the effects of uprooting, and a decrease in the average depth of pits on steep slopes was observed. Individual windthrow pits (five cases) initiated the activity of geomorphological processes, and two cases of periodic springs were noted. Changes in the relief of small landforms caused by tree uprooting were documented. Windthrow creation facilitated the delivery of the soil material from the slopes into the channels.     

Some remarks concerning the international ozone network

Summary The paper deals with the problem of the optimum distribution of ozone stations. The empirical orthogonal functions are applied.     

Decolourisation of Sugar Beet Molasses Vinasse by Ion Exchange

Sugar beet molasses vinasse is a by‐product of ethanol fermentation from sugar beet molasses. Its dark brown colour, which is attributable to the presence of caramels, melanoidins and invert alkaline degradation products, cannot be removed by biological methods. The novelty of this work lies in the use of conventional strongly alkaline ion‐exchange resins for the decolourisation of sugar beet molasses vinasse. The aim of the study was to determine the efficiency of two strong‐base ion‐exchange resins, Dowex 2 and Wofatit ES, when used for the decolourisation of sugar beet molasses vinasse. Optimal conditions and extent of decolourisation were related to the concentration and pH of the vinasse, the time of reaction with the resin, and also to the dose and type of the resin used. The greatest extent of decolourisation (92%) was achieved with Wofatit ES dosed in the amount of 5 g/100 mL of 25% vinasse with an initial pH of 10. The optimal time of reaction with the resin indispensable for attaining the maximal effect of decolourisation was 1.5 h for both resins. The highest extent of reduction in chemical oxygen demand (43%) during decolourisation of 25% vinasse (pH 10) was obtained with Dowex 2.     

Time-dependent shear velocities in channel routing

Abstract

The main aim of this study is the experimental investigation of friction velocities and shear stresses in rivers under unsteady flow conditions. Special measurements of mean velocities and other hydraulic parameters were made in two small lowland rivers in central Poland. Four controlled flood waves were released and analysed in the selected reaches. The main hydrometric characteristics and the relationship between water level and discharge were established. Friction velocities were obtained directly from the full St Venant equations of motion, as well as from only the steady momentum equation, and their time-dependent forms were established. Both these approaches provided similar results when the unsteadiness parameter was relatively low. It appeared that real friction velocities were much larger than those obtained from the common uniform flow formula. The passing hydrograph influenced the value of the shear velocity significantly.     

EPR and magnetism of the nanostructured natural carbonaceous material shungite

The X-band EPR and magnetic susceptibility in the temperature range 4.2–300 K study of the shungite-I, natural nanostructured material from the deposit of Shunga are reported. Obtained results allow us to assign the EPR signal to conduction electrons, estimate their number, N _P, and evaluate the Pauli paramagnetism contribution to shungite susceptibility. A small occupation (~5%) of the localized nonbonding π states in the zigzag edges of the open-ended graphene-like layers and/or on σ (sp ^2+x ) orbitals in the curved parts of the shungite globules has been also revealed. The observed temperature dependence of the EPR linewidth can be explained by the earlier considered interaction of conduction π electrons with local phonon modes associated with the vibration of peripheral carbon atoms of the open zigzag-type edges and with peripheral carbon atoms cross-linking different nanostructures. The relaxation time T ₂ and diffusion time T _D are found to have comparable values (2.84 × 10⁻⁸ and 1.73 × 10⁻⁸ s at 5.2 K, respectively), and similar dependence on temperature. The magnetic measurements have revealed the suppression of orbital diamagnetism due to small amount of large enough fragments of the graphene layers.