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1.
Investigations of chemical element distributions in soil, North Macedonia—a review
Trajče Stafilov, Robert Šajn, Jasminka Alijagić, 2024, izvirni znanstveni članek

Povzetek: This review article considers the following aspects: naturally distributed chemical elements and their enrichments, and the increased occurrence of PTEs due to anthropogenic and urban activities, as well as due to the geochemical uniqueness of certain geochemical landscapes, depending on the lithological environment. The review article is the result of many years of successful cooperation between the Geological Survey of Slovenia and the Faculty of Natural Sciences in Skopje, Ss. Cyril and Methodius University in Skopje, as well as several other institutions from North Macedonia, Russia and Romania but, also, through the voluntary and enthusiastic work of Prof. Trajče Stafilov’s PhD and Master’s students. To create the Geochemical Atlas, the territory of North Macedonia was covered with 995 sampling locations, but 16 separate areas with soil contamination were additionally sampled. The total sum of all collected soil samples was 3983 from 2449 different sampling sites in the period from 2006 to 2017. The analyses were performed at the Institute of Chemistry, Faculty of Natural Sciences in Skopje, at the Ss. Cyril and Methodius University in Skopje, North Macedonia, at the Research Institute for Analytical Instrumentation (ICIA), Cluj-Napoca, Romania, at the Joint Institute for Nuclear Research in Dubna, Moscow Region, Russia, and at Acme Labs in Vancouver, Canada. The sum of all analysed soil samples in all four mentioned laboratories was 7991 from 2006 to 2017. Using advanced mathematical methods such as multivariate statistical methods (HCA, FA, PCA) and artificial neural networks–multilayer perceptron (ANN-MP), predictions were made about the concentrations of potentially toxic elements (PTEs) and their distribution in real space. In less than two decades (2007–2023) of fruitful collaboration, a large number of scientific works have been published: 188 scientific publications, 8 geochemical atlases and 23 chapters in monographs.
Ključne besede: chemical elements, distribution, pollution, soil, North Macedonia
Objavljeno v DiRROS: 25.03.2024; Ogledov: 47; Prenosov: 13
.pdf Celotno besedilo (86,55 MB)

2.
Numerical modelling of macrosegregation in three-dimensional continuous casting of steel billets
Katarina Mramor, Robert Vertnik, Božidar Šarler, 2023, objavljeni znanstveni prispevek na konferenci

Povzetek: Macrosegregation presents a considerable defect in the continuous casting of billets and can critically affect the final properties of the product. The numerical modelling can help to predict and better understand the segregation and flow patterns inside the mould. The process is modelled with a physical model described by a set of conservation equations describing the t heat transfer, turbulence, fluid flow, solidification and segregation. A two-equation low-Re k-epsilon model and Abe-Kondoh-Nagano closures are used to close governing equations in this incompressible fluid flow example. The Boussinesq approximation is applied to account for the thermo-solutal buoyancy effects, and the Darcy approximation is applied for the description of the flow through the porous mushy zone. On a microscale, a lever rule solidification model is used to couple liquid fraction, temperature and concentration. The three-dimensional model is solved with the method based on local collocation with multiquadric radial basis functions on seven-nodded subdomains. The aim of this contribution is to explore the three-dimensional macrosegregation patterns of 0.51 wt% carbon steel in the solidified shell of the steel in the mould.
Ključne besede: modeling, continuous casting of steel, CFD, turbulence modeling, LES, meshless methods, RANS
Objavljeno v DiRROS: 21.03.2024; Ogledov: 56; Prenosov: 39
.pdf Celotno besedilo (1,48 MB)
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Moss as a biomonitor to identify atmospheric deposition of minor and trace elements in Macedonia
Robert Šajn, Katerina Bačeva Andronovska, Trajče Stafilov, Lambe Barandovski, 2024, izvirni znanstveni članek

Povzetek: The present work was carried out to obtain and highlight the fifth comprehensive baseline dataset on atmospheric deposition of trace elements and to assess air quality in Macedonia. In the period from August to September 2020, a total of 72 moss samples were collected in accessible areas in the country. The content of 28 elements (Ag, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Sr, Ti, U, and Zn) was determined using inductively coupled plasma–mass spectrometry. Based on the data obtained on the content of the elements, a factor analysis was carried out to identify and characterise different sources of pollution. In addition, distribution maps were created for all elements to show the regions most affected by anthropogenic activities. The survey conducted in 2020 has shown that air pollution with potentially toxic elements (PTEs) has slightly decreased compared to the results of the previous survey from 2015. This is due to the fact that, despite the operation of all mining and smelting facilities with the same capacity, government regulations for the installation of cleaning systems and additional regulations to reduce pollution have been introduced in the last five years. Nevertheless, the fact remains that the highest anthropogenic air pollution with PTEs is still caused by the operation of the ferronickel smelter in Kavadarci (Ni and Cr) in the southern part and by the lead and zinc mines in Probištip, Makedonska Kamenica, and Kriva Palanka in the eastern part of the country (Cd, Pb, and Zn).
Ključne besede: moss, atmospheric deposition, trace elements, air quality, Macedonia
Objavljeno v DiRROS: 20.03.2024; Ogledov: 54; Prenosov: 19
.pdf Celotno besedilo (9,64 MB)

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Overview of global long-distance road Transportation of industrial roundwood
Kärhä Kalle, Milla Seuri, Patricio Miguel Mac Donagh, Mauricio Acuna, Christian Kanzian, Vladimir Petković, Robert Renato Cesar Gonçalves, Costa Luis Henrique Suppi, da Cruz Rodrigo Coelho, Tihomir Krumov, Matevž Triplat, 2024, pregledni znanstveni članek

Povzetek: The aim of the study was to provide a comprehensive overview of global long-distance road transportation of industrial roundwood. The study focused on the maximum gross vehicle weight (GVW) limits allowed with different timber truck configurations, typical payloads in timber trucking, the road transportation share of the total industrial roundwood longdistance transportation volume, and the average long-distance transportation distances and costs of industrial roundwood. The study was carried out as a questionnaire survey. The questionnaire was sent to timber transportation logistics experts and research scientists in the 30 countries with the largest industrial roundwood removals in Europe, as well as selected major forestry countries in the world (Argentina, Australia, Brazil, Canada, Chile, China, Japan, New Zealand, South Africa, Türkiye, the United States of America and Uruguay) in February 2022, and closed in May 2022. A total of 31 countries took part in the survey. The survey illustrated that timber trucking was the main long-distance transportation method of industrial roundwood in almost every country surveyed. Road transportation averaged 89% of the total industrial roundwood long-distance transportation volume. Timber truck configurations of 4 to 9 axles with GVW limits of around 30 tonnes to over 70 tonnes were most commonly used. The results indicated that higher GVW limits allowed significantly higher payloads in timber trucking, with the lowest payloads at less than 25 tonnes, and the highest payloads more than 45 tonnes. The average road transportation distance with industrial roundwood was 128 km, and the average long-distance transportation cost in timber trucking was €11.1 per tonne of timber transported. In the entire survey material, there was a direct relationship between transportation distance and transportation costs and an inverse relationship between maximum GVW limits and transportation costs. Consequently, in order to reduce transportation costs, it is essential to maximise payloads (within legal limits) and minimise haul distances. Several measures to increase cost- and energy-efficiency, and to reduce greenhouse gas emissions in road transportation logistics, are discussed in the paper. On the basis of the survey, it is recommended that upto-date statistical data and novel research studies on the long-distance transportation of industrial roundwood be conducted in some countries in the future.
Ključne besede: timber logistics, timber hauling, timber trucking, gross vehicle weight, payload, transportation distance, transportation cost, cost efficiency, limit payload
Objavljeno v DiRROS: 28.02.2024; Ogledov: 96; Prenosov: 47
.pdf Celotno besedilo (1,77 MB)
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7.
Influence of the cell casing on the impedance of the lithium metal electrode
Sara Drvarič Talian, Jože Moškon, Elena Tchernychova, Robert Dominko, Miran Gaberšček, 2023, izvirni znanstveni članek

Objavljeno v DiRROS: 26.02.2024; Ogledov: 111; Prenosov: 57
.pdf Celotno besedilo (1,45 MB)
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8.
Assessment of differential expression of oncogenes in adenocarcinoma of stomach with fluorescent labeling and simultaneous amplification of gene transcripts
Uroš Rajčević, Petra Hudler, Gordan Mijovski, Gregor Gorjanc, Georg Hölzl, Stanislav Repše, Robert Juvan, Milena Kovač, Christian G. Huber, Radovan Komel, 2007, izvirni znanstveni članek

Povzetek: Background. Gastric cancer is one of the leading malignancies with a poor prognosis and low survival rates. Although the mechanisms underlying its development are still unknown, there is a consensus that genetic instability, inactivation of tumor suppressor genes and over-expression of oncogenes are involved in the early and late stages of gastric carcinogenesis. In the present study we wanted to display differential expression of seven oncogenes,namely CCNE1, EGF, ERBB3, FGF4, HRG1, HGFR and TDGF1. Patients and methods. We employed a method based on the multiplex reverse transcription polymerase chain (RT-PCR) method with a fluorescence detection. Results. More than half of patients (74.3%) out of total 74 with gastric adenocarcinoma had over-expressed at least one oncogene, with the exception of FGF4, which was expressed in tumor tissue of less than one third of patients. 56.8% of the patients patients showed over-expression of two or more oncogenes. Conclusions. Patients with precancerous lesions had elevated levels of TDGF1 or cripto-1 (64.9%) and CCNE1 (57.1%), suggesting that they could be used as markers for an early detection of malignant changes in stomach. Finally, the fluorescent multiplex RT-PCR method could be of value for rapid assessment of oncogene mRNA levels in small samples of tumor or precancerous biopsies.
Objavljeno v DiRROS: 20.02.2024; Ogledov: 94; Prenosov: 27
.pdf Celotno besedilo (86,60 KB)

9.
Assessment of atmospheric deposition of potentially toxic elements in Macedonia using a moss biomonitoring technique
Lambe Barandovski, Trajče Stafilov, Robert Šajn, Katerina Bačeva Andronovska, Marina V. Frontasyeva, Inga Zinicovscaia, 2024, izvirni znanstveni članek

Povzetek: This study aims to investigate the changes in atmospheric deposition trends in Macedonia, using a moss biomonitoring technique. This technique has been used to assess the content of potentially toxic elements in Macedonia in 2002, 2005, 2010, and 2015, within the framework of the International Cooperative Program on Effects of Air Pollution on Natural Vegetation and Crops. The content of 42 elements was analyzed using instrumental neutron activation analysis (INAA), inductively coupled plasma–atomic emission spectrometry (ICP–AES), and atomic absorption spectrometry (AAS), on 72 moss samples collected in the summer of 2015. The median values of the elements studied were compared with data from previous years and with median values obtained from comparable studies in Norway and the neighboring countries. Through factor and cluster analysis, three geogenic factors were identified: Factor 1, which includes the elements Al, Ce, Fe, Hf, La, Li, Na, Sc, Sm, Tb, Ti, Th, V, and U; Factor 4, which includes As, Cl, and I; and Factor 5, which includes the elements Ba and Sr. In addition, one geogenic-anthropogenic factor containing Co, Cr, and Ni (Factor 2), was identified, and one anthropogenic factor containing Cd, Pb, Sb, and Zn (Factor 3). The lead and zinc mines near the towns of Kriva Palanka, Probištip, and Makedonska Kamenica in the eastern region of the country, the former lead and zinc smelter in the town of Veles, and the ferronickel smelter near Kavadarci, have continuously had the greatest anthropogenic impact on the atmospheric deposition of potentially toxic elements during the time period of the study. In addition to the human influences, the lithology and the composition of the soil continue to play a significant role in the distribution of the elements.
Ključne besede: moss, biomonitoring, air pollution, potentially toxic elements, Macedonia
Objavljeno v DiRROS: 06.02.2024; Ogledov: 128; Prenosov: 40
.pdf Celotno besedilo (9,82 MB)

10.
Secondary deposits as a potential REEs source in South-Eastern Europe
Robert Šajn, Jasminka Alijagić, Ivica Ristović, 2024, izvirni znanstveni članek

Povzetek: The main objective of this manuscript is to collect, classify, and compile all available data about secondary mineral sources of REEs in the South-Eastern Europe (SEE). The material is generated from the extracting and processing sector, that might be possibly transformed in the business process becoming an important raw material for another industry. The management inventory guide will strengthen communication and dissemination efforts and simultaneously contribute to Europe’s self-sufficiency and support transitioning to green and digital technology. Identification of the knowledge gaps associated with secondary sources of REEs in SEE will contribute to connections between all partners being involved at the beginning, during the lifetime of products and at the end of the life cycle, represented with deposit owners, technology developers and potential processors, producers, and potential users. At the investigated area it was found 1835 individual landfills, most of them belonging to waste rocks. The total quantity of all material in SRM is about 3.2 billion tons on an area of about 100 km2. The largest 95 individual landfills were selected as potential prospective landfills, containing about 1600 million tons of material. The estimated total potential of REEs (ΣREE) is more than 200 Kt. The largest quantities are found in landfills for coal fly ash and Cu flotation, which correspond to more than 80% of the ΣREE. Most of the promising sites are located in Serbia and North Macedonia. It has been calculated that the valorisation potential and perspectivity of REE2O3 is about 32.5 billion USD (prices from December 2022). According to the average concentrations of REEs, the most prospective are the red mud dams but their total volume is limited compared to massive amounts of coal fly ash landfills. The REEs content in all type of investigated materials, especially in coal fly ash in North Macedonia is twice as high as in other countries.
Ključne besede: secondary raw materials, ESEE, rare elements, economic prospective
Objavljeno v DiRROS: 06.02.2024; Ogledov: 108; Prenosov: 27
.pdf Celotno besedilo (12,40 MB)

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