https://sci.ldubgd.edu.ua/jspui/handle/123456789/11173 Sun, 11 Jan 2026 19:32:43 GMT 2026-01-11T19:32:43Z https://sci.ldubgd.edu.ua/jspui/handle/123456789/11192 Title: Lead Speciation in the Technogenesis Zone of Coal Mining Sites (Case of Vizeyska Mine of Chervonohrad Mining Area, Lviv Region, Ukraine Authors: Karabyn, Oksana; Karabyn, Vasyl; Kochmar, Iryna Abstract: Total forms and "mobile" fractions of lead in dump rocks and adjacent territories of the impact zone of the Vizeyska mine of the Lviv-Volyn coal basin have been investigated. Environmental hazard caused by distribution of various forms of lead is analyzed basing on establishment of regularities of lead distribution in technogenesis zone. The concentration of lead in total form and acid-soluble, acetate ammonium and water-soluble extracts have been detected in argillites, siltstones, sandstones, coal from waste heaps, as well as in the soil at a distance of 50 m and 200 m from the foot of the heap. The content of total forms of lead in the waste heaps ranges from 4.72 mg/kg to 16.97 mg/kg. The concentration of lead in the acid-soluble extract is the highest in unburned coal - 3.39 mg/kg, the lowest in unburned siltstone 1.88 mg/kg. The reduction of lead content in ammonium acetate extract is somewhat different - from 1.5 mg/kg in unburned siltstone and burnt siltstone to 0.99 mg/kg in burnt sandstone. The lead content in the aqueous extract ranges from 1.25 mg/kg in unburned coal to 0.48 mg/kg in unburned argillite. The coefficients of lead concentration in the samples were determined by relation to the total form. The coefficients of lead concentration in the rocks species were determined by relation to the clarke. Due to the results of the research the waste heap rocks of the Vizeyska mine can be regarded as safe for the environment and suitable for use in terms of the distribution of various forms of lead in rocks and soils. Sat, 01 Jan 2022 00:00:00 GMT https://sci.ldubgd.edu.ua/jspui/handle/123456789/11192 2022-01-01T00:00:00Z https://sci.ldubgd.edu.ua/jspui/handle/123456789/11174 Title: Mathematical and Computer Model of the Tree Crown Ignition Process from a Mobile Grassroots Fire Authors: Karabyn, Oksana; Smotr, Olga; Kuzyk, Andrij; Malets, Igor; Karabyn, Vasyl Abstract: Forest fires cause great damage to the environment and are difficult to predict and eliminate. Mathematical models of temperature regimes of forest fires can create a scientific basis for improving the effectiveness of firefighting measures. The study of fire propagation pro cesses and temperature regimes during a fire is an urgent task that many researchers are engaged in. The processes of heat exchange in the process of fire are very complex and include many factors. For this reason, they are difficult to model. The equations of heat transfer processes them selves are also difficult to solve and obtain analytical solutions.The aim of this work is to create a mathematical model of the ignition of a needle from the flame of a moving ground fire. The solution of the set tasks was carried out by the method of direct integration.The model of the process of heating the lower part of the tree crown due to the moving grass fire described in this paper has the advantage that it is based on mathemat ical calculations that can be easily performed using the mathematical software package Maple. The program in the Maple package is offered, which, depending on the input data: the size of the fire area, the speed of fire spread, the distance from the ground to the bottom of the crown, calculates the air temperature. These results can be used to calculate and assess the operational situation during forest fires. Mon, 01 Aug 2022 00:00:00 GMT https://sci.ldubgd.edu.ua/jspui/handle/123456789/11174 2022-08-01T00:00:00Z