The research was conducted in the area of Northern Serbia. The lowland hygrophilous forests of Gornji Srem where pedunculate oak is the dominant tree species were studied. In the paper was investigated the content of essential and non-essential heavy metals (Cu, Zn, As, Mn, Co, Pb, Ni, Cd) on two different soil types: hydromorphic (fluvisol) and automorphic (chernozem). Three experimental plots were analyzed on each soil type. Soil loading with heavy metals was studied by soil horizons. Based on the obtained results, it was established that the concentrations of all elements are within the allowed concentrations, except for nickel (Ni), whose values on some experimental plots and horizons exceed the maximum allowed concentrations. Content of all investigated elements are higher on fluvisol, except for As, whose amount is similar on both soil types. The obtained results indicate that the loading of heavy metals in both soil types is within the allowed limits and there is no significant negative impact on the development and production characteristics of the forest ecosystems located in researched area.

One of the tasks of mathematics education is to develop students' logical thinking. Logical problems that require a certain level of sharpness, ingenuity, and rational reasoning present a good challenge that can further motivate students to engage with mathematics. The progress of science and technology has led to the emergence of numerous tools that can be used in mathematics education. With the advent of artificial intelligence, these tools got a more active role as communication with users reached a new user-friendly dimension resembling human-to-human interaction. The unpredictability of the flow and the speed of development of artificial intelligence raises the question of whether it will ever reach or surpass the level of human sharpness and ingenuity. This paper illustrates inaccurate and partially accurate reasoning of artificial intelligence in solving logical problems.

This paper aimed to examine specific factors that influence and have prognostic power on the profitability of selected insurance companies in the Republic of Serbia. Panel data were used for four insurance companies operating in the Republic of Serbia from 2013 to 2022, to estimate a linear model between the determinants that are theoretically expected to affect the performance and profitability of insurance companies. The findings of the paper revealed that company size according to all three methods (method of least squares, method of fully modified least squares, and robust method of least squares) has a significantly positive influence on the profitability of insurance companies. Also, the growth rate of the premium according to the fully modified least squares method has a positive (significant) impact on the profitability indicator, i.e. ROA. Seen from the other side, the weakest i.e., negative (significant) impact on the profitability of insurance companies in the Republic of Serbia was achieved by the independent variable expense ratio.

Red mud, byproduct of the aluminum industry, poses a significant environmental problem due to its chemical composition and the large quantities generated. This study explores the potential for its valorization through a multi-step process that includes reduction, leaching with acid solution, purification, and ultrasonic spray pyrolysis (USP). In the first step, red mud undergoes carbothermal reduction, during which metal oxides are transformed into metal phase and slag. In the second step, the slag is subjected to leaching under various conditions, including changes in pressure, temperature, and acid concentration, which allows the recovery of titanium in the form of titanium oxysulfate and other metals. Finally, after purifying the solution using precipitation or solvent extraction, ultrasonic spray pyrolysis is used to synthesize titanium dioxide (TiO₂) nanopowders from titanium oxysulfate (TiOSO₄). This integrated approach not only reduces waste but also produces high-value materials with broad industrial applications.

This paper aims to compare the mechanical and structural properties of butt-welded properties of dissimilar aluminum alloys 2024-T351 and AA 6082-T6 obtained by MIG and TIG welding processes. Alloy AA 6082 T6 is well weldable by classic fusion welding processes (MIG and TIG), while alloy 2024-T351 is almost non-weldable. For the welding of these two different Al alloys, MIG and TIG welding procedures were used on 8 mm thick sheet metal using additional material 4043A (AlSi5) and a mixture of argon and helium as a protective gas for the MIG welding process, or pure argon for the TIG welding process. The paper compares the mechanical properties of welded joints obtained by MIG and TIG welding. The microstructural evolution of the welded joint of dissimilar aluminum alloys AA6082-T6 and AA2024-T351 is compared. The mechanical properties of welded joints of dissimilar aluminum alloys are compared based on the results of Vickers hardness tests, tensile and bending tests of welded samples.

Introduction: Metacognition, which refers to the ability to oversee and regulate one's cognitive activities, plays a crucial role in medical education. Evaluating metacognitive awareness is particularly important for university students, as it impacts their learning strategies and academic performance. The objective of this study was to examine the psychometric characteristics of the Serbian adaptation of the Metacognitive Awareness Inventory (MAI), with an emphasis on its construct validity and internal consistency. Materials and methods: This was a cross-sectional study conducted at the Faculty of Medicine University of Belgrade, on third-year medical students during October 2024. The psychometric properties of the Serbian version of the MAI were evaluated by assessing its factorial structure and internal consistency. The MAI consists of 52 items, comprising two primary components: 'Knowledge of Cognition' and 'Regulation of Cognition'. The subcomponent of "knowledge of cognition" were categorized into declarative knowledge, procedural knowledge, and conditional knowledge, whereas "regulation of cognition" subcomponent were classified into planning, information management strategies, comprehension monitoring, debugging, and evaluation. Results: A total of 426 medical students were included in the study. The mean age of the respondents was 21.3 ± 1.4 years, and the majority were females (68.5%). The mean score of the scale was 199.0. The internal consistency analysis of the Serbian version of the MAI questionnaire yielded a Cronbach's a of 0.94, and a McDonald's o of 0.95 for the entire scale, which indicates excellent scale reliability. The Serbian version of the MAI questionnaire was validated using confirmatory factor analysis, supporting both the hypothesized eight-factor and two-factor structures. The eight-factor model showed good fit indices (IFI = 0.908, CFI = 0.905, RMSEA = 0.042), with statistically significant factor loadings (p < 0.05). Similarly, the two-factor model demonstrated adequate fit (IFI = 0.921, CFI = 0.918, RMSEA = 0.039), with all loadings also significant (p < 0.05). Conclusion: The present study revealed the Serbian version of MAI as reliable and valid tool for identifying medical students' metaconginive awareness.

TIG welding is used when a good weld appearance and a highest quality of the weld are required Nevertheless, the process has also some major disadvantages like relatively shallow penetration capability and low productivity. To increase the penetration and/or productivity, instead of traditional pure Ar, gas mixtures containing gases with high thermal conduction can be used. For austenitic stainless steels, as they are not prone to hydrogen cracking, also H2 is suitable. As H2 is active gas, the process is called Tungsten Active Gas (TAG). In this research, austenitic stainless steel sheet was welded with a competitive welding speed of 40 cm min−1, with pure argon and with Ar+7.5 H2 mixture. With pure Ar, a welding current of 220 A was far too small to reach full penetration in 3 mm sheet. With the 7.5 H2 active gas mixture, only 130 A was sufficient with unchanged welding speed.

Background: Degenerative aortic stenosis is a prevalent and severe condition necessitating aortic valve replacement (AVR) when the valve area critically narrows to 0.7 cm² or when symptoms are manifested. Traditional AVR via median sternotomy, poses considerable risks for patients with comorbidities or advanced age. Objective: This study evaluates the efficacy and safety of mini sternotomy aortic valve replacement (MSAVR), a minimally invasive technique designed to reduce surgical trauma, improve postoperative recovery, and lower healthcare costs. Methods: A reversed L-type upper partial sternotomy (RLUPS) approach was performed in five patients focusing on standardized surgical procedures, and rigorous postoperative care. Key findings indicate that MSAVR markedly reduces postoperative complications, ICU stay, and overall hospital stay compared to traditional sternotomy. Results: The median postoperative length of stay was seven days for MSAVR versus 12 days for traditional sternotomy, with ICU stays of 52 hours and 119 hours, respectively. Our study also highlights the cost-effectiveness of MSAVR, with decreased hospital costs per patient due to reduced ICU resource utilization and shorter hospital stays. These findings suggest that MSAVR is a valuable and advantageous alternative to traditional sternotomy, offering substantial benefits in terms of patient outcomes and healthcare efficiency. Conclusion: Our work underscores the potential of minimally invasive techniques in improving the management of severe degenerative aortic stenosis, marking a significant advancement in the field of cardiac surgery.

The first industrial robots appeared in the production processes of the 60s of the last century, and they are implemented to this day in all production processes in the world. The biggest application of industrial robots has been found in three industries in the world: the automotive industry, the electrical/electronic industry and the metal industry. The automotive industry is the first to implement the most industrial robots, and in recent years the electrical/electronics industry has also joined in, as these two industries in the world implement more than 60% of the total industrial robots implemented in the world. The use of industrial robots has been used to perform those tasks that are tiring and hazardous to the health of workers, which include welding, and the performance of these operations is mostly n the automotive industry. To date, the most implemented industrial robots of the first generation, which are robustly surrounded by fences (for the protection of workers), take up a lot of space and are complicated to reprogram. Development of new technologies such as: sensor technology, Internet of Things (IoT), big data, „cloud computing“, virtual and augmented reality (AR), artificial intelligence (AI), advanced security systems and others is credited with the development of robotic technology. In this paper is shown the trend of implementing industrial robots and their role in the welding process.