Dongqin Li, Yili Zhang, Peng Li, Jingjing Dai and Guohuan Li
As a type of natural energy resource, wind power is used in the modern implementation of wind-assisted technologies as a method for reducing the fuel consumption and environmental pollution of ocean-going ships. In order to promote the full usage of ocean wind energy for cargo ships, an innovative type of ship propulsion-assisted wing sail is proposed in this paper. The propulsion efficiency of this new wing sail can be increased by enlarging its area in both the transverse and vertical directions in good weather conditions, and it can be folded up automatically in poor weather conditions, improving the sailing safety of the ship. The sail parameters relating to the gaps and rotation angles between different parts of the wing sail are compared, and the values giving the best aerodynamic performance are identified using CFD simulation technology. The results for the lift and drag coefficients for the new wing sail at different attack angles are also compared with those of traditional aerofoil sails, including an arc-shaped rigid sail and a variable-camber sail proposed in 2015. From the viewpoint of the sailing performance of the vessel, our results demonstrate that this new type of wing sail has good aerodynamic performance and can reduce fuel costs for commercial vessels.
Results of research of the identification of flooding as a result of groundwater table fluctuations on the example of the valley of the River Vistula, with the use of multi-spectral Sentinel-2 images from the years 2017–2018 are presented. An analysis of indexes of water use, calculated on the basis of green, red and shortwave infrared (SWIR) bands, for extraction of water objects and flooded areas was carried out. Based on the analyses conducted, a mapping method was developed, using three water indexes (MNDWI Modified Normalised Difference Water Index, NDTI Normalised Difference Index and NDPI Normalised Difference Pond Index). Results show that the 10 metre false colour composite RNDTIGNDPIBMNDWI obtained significantly improved submerged extractions more than did individual water indexes. Moreover, the 10-m-images of MNDWI and NDPI, obtained by the sharpening High Pass Filter (HPF), may represent more detailed spatial information on floods than the 20-m-MNDWI and NDPI, obtained from original images.
Andrzej Tomporowski, Ali Al-Zubiedy, Józef Flizikowski, Weronika Kruszelnicka, Patrycja Bałdowska-Witos and Jacek Rudnicki
The design of a floating, innovative device for river water aeration and conversion of mechanical energy to electrical energy required the analysis of a number of geometrical and dynamic features. Such an analysis may be carried out on the basis of existing methods of numerical fluid mechanics. Models of pressures, forces and torques characteristic for the conversion of watercourse energy were developed for two basic concepts of innovation. These pressures, forces and torques were calculated, designed, and experimentally determined for the variable geometric form and dimensions of the designed working elements of the innovative roller-blade turbine rotor.
Adam Bogacz, Maria Andrzejczak, Klara Tomaszewska and Magda Podlaska
Drainage and peat extraction may have a negative impact on existing hydrological conditions and, consequently, on the conditions of wetland ecosystems. The aim of this study was to assess human impact on the studied Trzcińskie Mokradła Peatland by comparing the concentrations and trace element (Pb, Zn, Cu, Cr and Ni) pools in the study area (extracted vs. non-extracted areas of peatland). The concentration of trace elements in organic soils and their pools were analysed in relation to their depth in the soil profiles, content of organic matter, soil pH values and the degree of decomposition of organic materials (peat, mursh). Fifteen soil profiles (90 samples) were examined. The total soil elements content was determined after digestion in a mixture of HCl+HNO3. The element pools were calculated and expressed in g m−2 of soil in 0–30 cm and 30–50 cm layers. Soils showed acidic or slightly acidic reactions. The high concentrations of Pb and Zn were mainly observed in the upper horizons. The deeper layers enriched with mineral fractions were also enriched in metals like Cr and Ni.
We investigated the spatial variation patterns of voting results in Polish parliamentary election in 2015 across 380 regions. That election was a milestone event in Polish politics that substantially affected Poland’s internal and foreign policy directions and promoted two emerging political parties as runners-up against the well-established ones. While socio-economic, cultural and geographical factors such as economic activity, historical legacies (post-Russian East vs post-German West) and economic dichotomies (cities vs the countryside) explain most variations for most parties, they do not appeared to fit as determinants of the new parties’ support, especially of right-wing populists. Demographic target groups of individual parties appear to be relatively unresponsive to their pre-election offerings. The spatial specification of econometric models considerably improves their statistical properties. We also examined mixed-W models to account for the unobservable spatial effects stemming from the construction of constituencies. Their distinctive sets of candidates added significantly to the explanation of the spatial variation in voting.
The aim of this study is to differentiate old-field plant communities along the abandonment time and/or environmental gradient in the landscape surrounded villages with established Czech settlers in Romanian Banat area conserving traditional agriculture, and to identify site factors which cause plant diversity of particular vegetation types. Study area: Wider territory centered by the village Sfânta Elena, southern Romania ((44°40’ N; 21°43’ E). Methods: We collected 97 phytosociological relevés covered the same number of old-fields in the area and the following habitat parameters were measured: soil pH, available phosphorus, total carbon and nitrogen, Heat Load Index. Software TURBOVEG / JUICE was used to collect and elaborate the data set of relevés. Old-field vegetation was classified into five basic plant communities using TWINSPAN (all the botanical material includes 291 plant species). For each community, we detected diagnostic species according to their fidelity index. The presence of mowing, grazing or burning was registered for recorded stands. Ecological preferences of each community were examined using one-way analysis of variance (ANOVA). Vegetation-environment relationships were analysed using ordination method – Cannonical correspondence analysis (CCA) in CANOCO for Windows (version 4.5) to find the main variability gradients within the dataset. Scatter plot relationships between variables were constructed. Main results and conclusions: Dependence of number of species (alpha diversity) on the abandoned field’s age exhibits an unimodal shape of this relationship with the maximum peak of species diversity in plant stands aged approximately 13 years. The most importnat ecological factors and/or type of management in the relationship to the old-field plant composition show the following significance order: available phosphorus content in the soil (P), total nitrogen content in the soil (N), presence of burning, length of abandonment (old-field age), carbon/nitrogen ratio in the soil (C/N). Other parameters (grazing, mowing, zero management) do not demonstrate effective impact according to our dataset and seem to be equal to the absence of burning.
Jan Prostředník, Vítězslav Kuželka, Lenka Kovačiková and Jan Novák
Archaeological research in the area of the chateau park uncovered the relic of the Gothic church of St. Elisabeth, dated to the second half of the 13th century. It is a single-nave building with a rectangular finish (length 25 m, boat width 13 m, presbytery width 10.5 m). The church probably had an older predecessor - a wooden structure on a stone foundation, dating from the mid-13th century. At the same time, the church site was a burial place: a grave of a young woman and a 1.5-year-old child, dated 13th/14th century were found outside the presbytery wall. In the presbytery, there were 3 graves of men dating back to the 14th century. It is very likely that these are the Lords of the Wallenstein family. Archaeological research in graves in the Church of St. Elisabeth unearthed a small collection of animal bone remains. The occurrence of bones of young and mature cattle and domestic fowls, which are abundant in the archaeozoological assemblage, indicates the prevailing meat consumption of these animals. The butchering marks on their bones document removal of meat from the carcasses.
L. Blaga, Ioana Josan, G. V. Herman, V. Grama, S. Nistor and N.-Sz. Suba
The present study deals with the estimation of the evolution tendency of the environmental stage of a protected habitat with predominant forest vegetation, during a short period of time, using techniques specific to remote sensing. Therefore, two important spectral indexes were tested while assessing the health of the forest ecosystems: i.e. the Normalized Difference Vegetation Index (NDVI) and the Structure Insensitive Pigment Index (SIPI). The period of time taken into consideration for the study was, 2013 - 2019, having used medium resolution satellite photos, Landsat 8 OLI, having initially undergone standard pre-processing operations (resize data, radiometric calibration, atmospheric correction). The satellite images modified according to the Top of Atmosphere Reflectance and corrected topographically resulted into getting values for the two before mentioned indexes. The quantity-spatial results obtained, correlated to the monthly values of the precipitations processed in order to obtain the SPI (Standardized Precipitation Index), mostly reveal, in what SIPI and also NDVI are concerned, a slight decrease in the quality of the forest on the analysed area in the sense that the vegetation stress is increased under meteorological factors, expressed differently depending on the morphometric and pedological parameters of the habitat.