Geosciences and Engineering

Symbols used on ethnic maps in the early decades of the 20th century

János Jeney — 2024-09-21

While most maps are a representation of the surface of the earth at a reduced scale, some maps known as thematic maps are a representation of data distributed on the face of the earth. Within thematic maps, ethnic maps make up a special group since they have played a large role in defining state borders, especially during and after the First World War when territorial demands were made which were justified using ethnic maps. Many different mapping methods have been tried and while many can give a very accurate picture their interpretation is time-consuming hence they cannot be presented to decision-makers. This paper presents those mapping methods together with their scale which are ideal to be used for decisions on borders and analyzes their accuracy.

Application of column tests to derive transport parameters of manganese in mine waste dump material of Rudabánya

Márton Tóth — 2024-10-07

The most accurate method to create a transport model of an area is to determine the transport parameters of a contaminant in the investigated porous media. The batch and column tests are the tools that can be used to derive this information. To describe the transport process in a column, 1D transport equation is applicable therefore the equation's analytical solution becomes possible. In our work, two-column test setups were investigated from the aspect of their accuracy in the determination of longitudinal dispersivity, retardation factor, and irreversible reaction rate constant, respectively. In the first measurement method, a solution with constant concentration (0.01 M Mn solution) was percolated through the column filled with mine waste dump material. In the second measurement method, distilled water was percolated through the column continuously but in a moment an impulse amount of manganese (10 ml 0.5 M Mn solution) was injected into the column at its bottom. The first measurement served the breakthrough curve (BTC), and the second measurement resulted the impulse curve (IMP). The retardation factor of Mn found in the media is similar in both measurement setups (R_BTC=1.87, R_IMP=1.47). The value of the irreversible reaction rate constant differs in the two experiments; an order of magnitude difference was found between the result of the breakthrough test (µ_BTC=6.94·10^-5 1/s) and the impulse test (µ_IMP=2.09·10^-4 1/s).

On the impact of hydrocarbon contamination on compaction and plasticity behavior of sandy clay soil. Case study: Northeast Hungary

Sirine Trabelsi — 2025-01-21

This study investigates the behavior of hydrocarbon-contaminated soils, using Atterberg tests and Modified Proctor Tests (MPT) conducted on sandy clay soil samples. By exposing the soil to higher artificial contamination percentages than has been reported in the literature, our approach gives a further comprehensive
analysis and provides a complex interpretation of the contamination process and its impact on compaction. The oil contamination led to an increase in the plastic limit and a decrease in the plasticity index. It also influenced the compaction behavior, resulting in a decrease in the maximum dry density. The analysis emphasizes the significance of considering higher contamination levels for a more robust understanding with implications for diverse engineering applications.

Direct porosity measurement using single chamber gas pycnometers

Roland Dócs — 2025-02-18

During porosity measurements, error most certainly originates from the incorrect determination of the samples total geometrical volume. This uncertainty will affect all porosity measurement procedures with greater degree on the indirect methods. However, there is a solution where the effect of the sample volume can be eliminated. If both the matrix and pore volume of the sample is measured the porosity can be calculated using those values instead of the bulk and pore volumes. The two-chamber gas pycnometer is the most used method for determining the matrix volume. The procedure applies Boyle's principle which can also be used to determine the pore volume directly using a single chamber construction, if the difficulties discussed in this article are solved.

Combustion properties of hydrogen-natural gas mixtures from 0 to 100 % hydrogen content

Katalin Tomkóné Nyiri — 2025-07-04

In the past few years, a rising interest has been seen in the use of hydrogen. In the long term, the aim is to replace natural gas, as it is one of the most frequently used energy sources in the EU. In the meantime, blending hydrogen into the existing natural gas pipeline network is also thought to be a promising strategy in environmental aspects. One of the most important environmental benefits of switching from natural gas to hydrogen is the decreasing amount of greenhouse gases coming from combustion. This study focuses on the changes that injecting hydrogen into the natural gas grid causes the combustion characteristics of the mentioned substances. This paper investigates whether the combustion characteristics change drastically if the volume of hydrogen varies between 0-100 % or not.

Preparation of a candlestick-shaped stalagmite’s digital 3d shape

Dóra Rábai — 2025-07-07

A digital 3D model of the tallest and most vulnerable stalagmite in the Plavecká priepast (Detrekői-zsomboly) in the Little Carpathians (Slovakia) has been created from laser scanning data captured by a Leica BLK 360 instrument. The point cloud was processed using the Leica Cyclone and Cloud Compare software. The 3D digital model was compared with a previous model made in 2015. This comparison provides information not only on the growth of the stalagmite, but also on the discrepancies between surveys taken at different times.

Analyses of graphite-bearing schists from Fertőrákos, Sopron mts., NW-Hungary

Lívia Leskóné Majoros — 2025-07-07

Potential graphite-bearing schists are investigated from Fertőrákos (Sopron Mts., NW-Hungary) with ore microscopy, scanning electron microscopy, Raman spectroscopy, X-ray powder diffraction and X-ray fluorescence spectrometry. Disordered graphite is identified by Raman spectroscopy, which appears as <50 µm sized flakes, and as 50–300 µm sized lense-forming granular aggregates in the deformed zones of the samples detected by ore and scanning electron microscopy. Using graphite geothermometry on Raman spectra, the average formation temperature of the Fertőrákos samples is ~440 °C (±50 °C).

Mitigating metal loss in waste printed circuit boards reverse flotation: The critical role of particle dispersion

Alaa Abbadi — 2025-07-21

Froth flotation is emerging as a key step in waste printed circuit board recycling (WPCB) recycling, enabling the selective separation of metals from nonmetals. This study investigates the aggregation and dispersion behavior of WPCB particles during pulping and evaluates intense agitation as a pretreatment strategy. The inherent hydrophobicity of WPCB nonmetals drives spontaneous aggregation, which entraps metallic particles and stabilizes persistent foam layers that hinder separation. Intense agitation effectively disrupts these aggregates, releasing entrapped metals and improving dispersion. Under optimized conditions, this pretreatment significantly enhanced flotation performance by mitigating metal losses to the overflow.