This article describes salt distribution (Ca2+, Mg2+, K+, Na+) in halophytic plants, common reed (Phragmites australis) taken from four locations in Ostrava - Důl Lazy, Karvinský potok, Heřmanický rybník, Nový rybník. The research aimed to find out where salts, but also other elements acting as contaminants in the environment are stored, how they are distributed, what physiognomic changes they cause in the plant, and to what extent common reed can face the stress conditions of salinity in the phytoremediation process.The experiment took place under controllable conditions in the phytotron - temperature 25 °C, light regime 12 hours day/12 hours night, air humidity 60 %, light intensity 150 μmol.m-2.s-1. Bunches of reeds were subjected to gradual salinization with 1% to 5% Darkov salt solutions. Biomass samples were analyzed by instrumental neutron activation analysis (NAA) and atomic absorption spectrometry (AAS) methods.Based on the results of measurements conducted using the AAS and NAA methods, it can be concluded that the dominant element in the reed beds at all four specified sites of interest is potassium. It is bioaccumulated in the aboveground part of the plant. The highest concentration of potassium was found in the aboveground part of the reeds from the Karvinský potok site; the lowest was observed in the aboveground part of the reeds from the Nový rybník site.The growth analysis was not conducted according to the methodology, but another interesting finding is that reed beds from the Nový rybník site exhibited the best tolerance to salt stress and the gradual process of salinization with 1% to 5% solutions of Darkov salt.
Photovoltaics are currently experiencing a huge boom in Europe. European policy is focusing on the deployment of renewables in the energy sector and the electrification of the European vehicle fleet. This article focuses on comparing the efficiency of different types of materials and technologies in the construction of PV panels and briefly summarises current technologies for recycling PV panels after the end of their productive life. One of the panels compared was part of a field measurement and its values are partly reported by the manufacturer, partly measured and partly calculated. The other values for the sample of materials used are obtained from scientific literature or annual reports of the manufacturers. The article shows that the original average values of 10% to 20% efficiency of PV panels are still shifting, and some materials and technologies now allow efficiencies of up to 38%. High hopes are especially placed on perovskite materials, GaAs cells, or combinations of these with other materials.Unfortunately, we have not made much progress in the recycling of photovoltaic panels and, with minor modifications, the methods already used for the first generation of photovoltaic panels are still used. These are mainly the mechanical method, the chemical method and combinations of these.
This research investigates the intrinsic value of stocks of companies within the oil extraction sector. The focus is on publicly traded corporations part of "Big Oil": ExxonMobil Corporation, Chevron Corporation, TotalEnergies SE, BP plc, Shell plc, and ENI S.p.A. The numerous fundamental analysis intrinsic value of stocks models is being applied to the Big Oil consortium. This article stands out for its unique focus on utilizing dividend discount models, earnings models, and cash flow models to calculate the intrinsic value of stocks in major oil companies, which is currently missing in existing studies as of April 2024. Through this approach, it not only forecasts stock prices but also provides investment recommendations, offering fresh insights into stock evaluation and uncovering potential investment prospects within these companies according to intrinsic value of stocks. Specific mathematical models for the intrinsic value of stocks are applied to each examined company for this calculation. The intrinsic value of stocks in companies recommended for investment was found to be undervalued by 7.25% for dividend discount models, 8.25% for earnings models, and 36.75% for cash flow models compared to their current market values. The assessment of intrinsic value of stocks reveals the suitability of investing in these companies: TotalEnergies SE, BP plc, Shell plc, ENI S.p.A. These results offer valuable insights for stock investors in the oil sector, as well as organizations under investigation and other stakeholders in the oil extraction industry.
Dendrological research investigating the influence of anthropogenic and natural factors on the dendroflora was carried out at six post-mining sites: the "Halda Ema" mine dump, part of the Terezie tailings, the slopes of the Petr Bezruč mine dump, the Mokroš wastepond, the Darkov Sea area and surroundings of Loucké ponds (Ostrava and Karviná regions). The reference area was a mixed deciduous forest in the Landek NNM in Ostrava. Our research findings confirm that anthropogenic and natural factors have a significant influence on the distribution and composition of woody flora in post-industrial sites. We noted significant differences in biodiversity between reclaimed areas and naturally regenerating areas, which points to the need for targeted management and conservation strategies to support the sustainable restoration of these landscapes. The highest levels of biodiversity were found at the "Halda Ema" mine dump, suggesting that site-specific characteristics are key to supporting species diversity. The results underline the importance of long-term monitoring and analysis of the influences that shape the woody flora in these areas, and emphasize the need to integrate ecological, social and economic aspects into the regeneration process. Variability in the biodiversity of woody plants between individual locations was revealed, with the greatest diversity at the "Halda Ema" dump and part of the Terezie tailings. Our study also reveals a higher prevalence of native plant species over invasive species in most of the monitored sites, which may reflect favorable ecological conditions or effective management strategies that prevent the spread of invasive species. These patterns, which agree with previous studies, suggest that ecological factors including habitat preference and human influence play a critical role in plant community dynamics. These findings expand our understanding of the process of landfill succession and the factors influencing biodiversity, reinforcing the importance of an integrated approach in ecological and environmental research to inform conservation and management practices.
From tennis through volleyball to athletic sports, clay plays important role as subsoil. The bulk material, clay, is cheap, because it is recycled product made at low cost by crushing bricks and clay tiles. Due to its compressibility and friction properties, it is an ideal material to produce clay courts. Therefore, friction parameters, compressibility factors and flowability were investigated. These mechanical-physical properties are also important for the practical handling of these materials, such as storage and transport of the material. For this purpose, three basic types of clay powder were characterized and compared. Experimental work was performed using Schulze RST-01 rotary shear tester, Powder Rheometer FT4, laser particle analyzer Cilas 1190 and particle analyzer CAMSIZER. Shape analysis of the samples was also performed. The subject of the research was how the volume changes depending on the applied normal stress, and the dependence of the internal friction angle. Initial results showed that variations in the shape and size of the clay particles can cause differences in the behavior of the tested powders.
In today's Europe, passporting is mainly carried out by private landscaping companies, which offer their customers a complete appreciation of their property on the market. From the private sector of individuals, this is not a frequent phenomenon in our country. In the Czech Republic, this trend is limited mainly by the financial situation of the majority of the population. These services are thus used in the state sector by the administration of parks and greenery, which must keep records of all costs of maintaining public greenery.The inventory of greenery is discussed abroad mainly in connection with forest management, which, in contrast to orchard evaluation, broadens its horizons to other attributes, including substance flows, soil erosion, the amount of biomass and the amount of excavated material. With the growing consumption of wood and the global problems related to this issue, the ecological value of greenery, which is often introduced into legislation, is being emphasized in EU countries, but also in the Western world.The thesis focuses on the passportization of vegetation greenery in the Šenov Chateau Park. It deals mainly with a new method of evaluation, which consists of calculations using a professional calculator prepared by the Agency for Nature and Landscape Protection. Furthermore, this thesis deals in detail with the changes that have taken place since the last inventory within the revitalization of the Castle Park, which was carried out by Ing. Petr Ondruška. At the end of the thesis, there is a map and a proposal for further care. Lists of taxa can be viewed in the appendices, which are a guide for the entire evaluation.
The phenomenon of water erosion is a complex one that is very much in evidence around the world and also in the watersheds of northern Algeria, where the physical, hydroclimatic, geomorphological, and socioeconomic conditions are highly conducive to the onset and acceleration of this phenomenon. Our country is characterized by a semi-arid climate and is threatened by erosion of agricultural land. High concentrations of suspended sediments carried by wadis towards dams and hill reservoirs significantly reduce the capacity of these structures. The majority of Algeria's wadis are not gauged, which complicates the collection of data on solid transport. In the absence of such data, water resource planners find it even more difficult to assess this important hydrological feature. To this end, we are proposing a methodology for calculating the solid transport of rivers that are not gauged by hydrometric stations. To make the model more rigorous, we used data from 132 hydrometric stations. We applied Principal Component Analysis to the monthly mean solid flows of 132 hydrometric stations, and the results show the existence of four hydrologically homogeneous groups. Each group is influenced by distinct parameters, given the complexity of this phenomenon. In the absence of measurement data, these results can be used by engineers and planners working in the hydraulics sector, often without the benefit of normative documents.
The accumulation of heavy metals in rivers’ sediments near industrial wastes and mining activities has been a serious issue in developing countries including Rwanda and it has caused different environmental impacts on aquatic and terrestrial lives. Environmental studies have reported heavy metals pollution (lead, manganese, copper, zinc, nickel, iron, and cadmium) in major Rwandese rivers such as Mpazi, Rusine, and Nyabugogo. The increase in heavy metal concentrations in the environment results in abnormal enrichment, which in turn, affects the surrounding environment. This study aimed to investigate the heavy metals in Nyabarongo sediments, Mageragere sector using both X-ray fluorescence (XRF) and Atomic Absorption Spectrometer (AAS) instruments. Sediments samples were collected systematically on four sampling stations and the results showed that the Cadmium (Cd), Lead (Pb), and Manganese (Mn) concentrations among the investigated heavy metals are above the Rwanda Standard Board (RSB) and World Health Organization (WHO) guidelines for soils and sediments, meaning that those metals are the measure pollutants in the sediments of Nyabarongo River and the study has recommended the people around the river to reinforce the erosion control measures and not to use Nyabarongo water for domestic use and animal farming activities because of the concentration of heavy metals it contains that are toxic to animals, plants and micro-organisms. Keywords: Heavy metals; Nyabarongo River; Pollution; River sediments; World Health Organization (WHO).
A detailed geophysical investigation was carried out to determine if the subsurface geology is responsible for the failures along this road section. This study aims to image and identify competent, moderately competent, and incompetent zones of the subsurface soil and thus to find out if geology is responsible for the failure along this section of the road. Electrical Resistivity Imaging (ERI) using the Wenner array 2D Imaging, and Vertical Electrical Sounding (VES) using the Schlumberger array were adopted for this survey. The geoelectric section from the VES revealed the presence of 3 lithological layers; topsoil, weathered layer (clay, sandy clay, clayey sand), and basement, which is also true for the electrical resistivity images revealed by the 2D electrical resistivity imaging. The results showed that the shallow subsurface beneath the road section is mostly underlain with clay that is geotechnically incompetent and not suitable for construction. The causes of road failure are believed to be the result of the incompetent clayey topsoil and the weathered layer seen in the profiles, which expand when absorbing water and shrink when drying, thus causing instability beneath the pavement due to the low shear strength and high compressibility, and also due to fractured basement rocks at shallow depths. Keywords: Basement; Clay; Resistivity; Road failure, Subsurface; Topsoil.
