Vinča Institute of Nuclear Sciences
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Tailoring textural properties of activated carbon produced from Plane tree (Platanus) seeds using alkali (NaOH) activation with improved post-activation treatment procedure for environmental and energy applications
No full textA highly-ordered mesoporous/microporous activated carbon (AC) was successfully synthesized from rarely used biomass precursor (Plane tree seeds), through three-step production process. The process involved subjecting raw material to hydrothermal carbonization (HTC) in autoclave under moderate temperature conditions (250 °C), and then produced hydrochar was activated by alkali using NaOH, through dry impregnation. The third step was an improved post-activation period, which included high-temperature carbonization at 850 °C. The specific surface area of manufactured AC (PTS-AC-NaOH) was in a domain of the commercial carbons (SBET = 1508.6 m2/g). According to its textural and morphological characteristics, PTS-AC-NaOH is characterized by the most frequent pores with a diameter of 2.05 nm, as well as wider pores of 3 nm, and specific super-micropores, with diameter of 1.884 nm. Material contains mostly slit-shaped pores in micro-mesoporous domains, where additional analyses were showed that pores are relatively uniform in a size and shape. Due to its physicochemical properties, PTS-AC-NaOH has proven to be an ideal candidate for applications in purification of polluted aquatic environments, air and harmful industrial gases, and as a good choice for electrode material in supercapacitors. During thermal restoration process of PTS-AC-NaOH, a strong exothermic effect was identified, and it was attributed to intercalation of Na+ ions (at higher temperatures) into amorphous carbon structure, a most often on defects/edges and interlayer spaces. Observed phenomenon proved to be significant, in the sense, that restored material (with a changed carbon structure) can be used as good anode material for sodium-ion batteries. Complete restoration process was mechanistically described using various isoconversional methods, through changes in the values of effective kinetic parameters with conversion
A new paradigm of energy transition: security and economic aspects of small modular reactors
No full textSmall Modular Reactors (SMRs) represent an innovative and promising technology in nuclear energy, combining economic viability, operational flexibility, and enhanced security standards. This paper explores the economic benefits of SMRs, including lower capital costs, shorter construction timelines, and scalability, making them an attractive option for both developed and developing countries. Additionally, their advanced security features, such as resilience to external threats and reduced risk of nuclear material proliferation, address critical concerns associated with traditional nuclear reactors. The analysis also considers security challenges and the market acceptance of SMR technology, which remain key hurdles to its widespread adoption. SMRs offer significant potential for contributing to the energy transition by supporting the diversification of energy sources, reducing greenhouse gas emissions, and enhancing energy security, particularly in regions with limited access to reliable power. This paper emphasizes the importance of balancing economic feasibility with robust security measures, offering insights into how SMRs can play a transformative role in achieving sustainable energy goals.International Conference “Annual conference on Challenges of Contemporary Higher Education” : February 2nd-7th, 2025, Kopaonik
Shanghai cooperation organization - analysis of the model for further development
No full textThe Shanghai Cooperation Organization is one of the most important regional multilateral mechanisms in Eurasia. From an organization for the resolution of border disputes, it has developed into a complex system that includes eight full members, several observers and partners for dialogue. Today, the Shanghai Cooperation Organization represents a platform for strengthening regional stability, economic integration and the promotion of multilateralism. At the same time, the Shanghai Cooperation Organization faces enormous challenges, which are primarily reflected in defining its role in global politics. The aim of the work is to analyze models of possible further development of this organization. Also, the potential consequences of the expansion of its work are analyzed, especially in the context of new global initiatives and great power rivalry.International Conference “Annual conference on Challenges of Contemporary Higher Education” : February 2nd-7th, 2025, Kopaonik
Significance of Electrolytic Enrichment in the Determination of Tritium
No full textTritium, a radioactive isotope of hydrogen, is commonly found in environmental water samples at very low concentrations. This radionuclide occurs in nature, originating from natural sources (produced in the atmosphere from the interaction of cosmic radiation with atmospheric nitrogen) and anthropogenic sources (nuclear weapons tests, the operation of nuclear power plants, reprocessing of nuclear fuels). Its presence in the environment can be an indication of the presence of other artificial radionuclides, so the knowledge of the concentration of this isotope is of great importance. Tritium is pure beta emitter, with low energy (maximum energy=18.6 keV), and the common methods for counting of tritium are either gas-proportional counting (GPC) or liquid scintillation counting (LSC). Due to the low specific activity in water, direct measurement is not suitable without prior preparation of the sample using electrolytic enrichment. Electrolytic enrichment increases the tritium activity in water samples at measurable level, thereby improving the sensitivity and accuracy of measurements. During electrolysis, the sample volume is reduced for 10-15 times, making detection via liquid scintillation counting more effective. The analysis of the results obtained as part of the intercomparison, in the case of samples with low activity of tritium, shows that the application of electrolysis for the purpose of determining the concentration of tritium is much better. The application of electrolytic enrichment is significant during the tritium determination in environmental waters (precipitation, drinking water, surface water, groundwater).5th International Meeting on Materials Science for Energy Related Applications, September 25-26, 2025, Belgrade
Multifunctional Ho-Doped BiFeO₃ Nanopowders: A Potential Platform for Energy Conversion and Storage Applications
No full textBi1-xHoxFeO3 ultrafine nanopowders were synthesized by the hydrothermal method. Here we use a simple, low-cost and energy-saving hydrothermal method, which has advantages over the conventional methods. The diffraction pattern was recorded at room temperature and atmospheric pressure in the absence of any re-heating of the sample. A fitting refinement procedure using the Rietveld method was performed, which showed the incorporation of Ho3+ ions in the BiFeO3 crystal lattice, where they substitute Bi3+ ions. All the samples belong to the R3c space group. Furthermore, bond valence calculations (BVC) identified six energetically favourable structural modifications of the Ho-doped system: a- , b-, g-, R-, T₁-, and T₂-phases. These structural configurations were further examined using advanced computational simulations based on density functional theory (DFT) to evaluate the stability of different magnetic orderings, electronic structures, and the evolution of ferroelectric properties with increasing Ho concentration. The results of our theoretical and experimental investigations reveal a rich spectrum of electronic and magnetic phenomena in Ho-doped BFO, offering new insights into the control of multiferroicity through doping. These findings have significant implications for further research and the development of advanced multiferroic materials with enhanced functional properties, suitable for innovative nanoelectronic and spintronic applications.5th International Meeting on Materials Science for Energy Related Applications, September 25-26, 2025, Belgrade
Investigation and characterization of Co0.9Gd0.1MoO4 nanopowders obtained by modified glycine nitrate procedure
No full textThe glycine nitrate procedure (GNP) is a highly efficient method for controlling the composition and morphology of Co0.9Gd0.1MoO4 synthesis. This combustion technique allows for precise management of stoichiometry, homogeneity, and purity. By combining metal nitrates with glycine in specific ratios, GNP produces Co0.9Gd0.1MoO4, a material known for its unique properties. Once the synthesis is complete, the resultant samples undergo a rigorous and comprehensive analysis utilizing an array of sophisticated characterization techniques. These include Differential Thermal Analysis (DTA), which provides insights into thermal stability; X-ray Diffraction (XRD), revealing crystal structure and phase identification; Fourier Transform Infrared Spectroscopy (FT-IR), which uncovers molecular bonding and functional groups; and Field Emission Scanning Electron Microscopy (FESEM), offering high-resolution imaging of particle morphology. Additionally, nitrogen adsorption methods are employed to assess surface area and porosity. This multifaceted analysis uncovers a notable degree of anisotropy in both the shape and size of the synthesized particles, which frequently coalesce into complex agglomerates. Furthermore, significant variations in the microstructure manifest, leading to the formation of strikingly organized plate-like crystals that exhibit both aesthetic and functional significance. Moreover, when the synthesized materials undergo thermal treatment, a remarkable transformation occurs, evidenced by a vivid change in color—from deep, saturated tones to lighter, more luminous shades. This vibrant color shift is intricately linked to pronounced changes in the dominant wavelength, as measured in nanometers, and an increase in color purity. This transformation is particularly striking when comparing the starting sample to one heated to a high temperature of 1100 °C, and these changes can be primarily attributed to fluctuations in cobalt concentration within the material. Such insights into the synthesis and post-synthesis alterations underscore the sophistication of the GNP method and its profound implications for material science advancements.5th International Meeting on Materials Science for Energy Related Applications, September 25-26, 2025, Belgrade
Electrochemical Surface Modification and Effects on the Catalytic Activity of Nickel-based Electrodes for Hydrogen Evolution
No full textThis study explores the impact of electrochemical surface preparation on the catalytic activity of nickel-based electrodes for the hydrogen evolution reaction (HER) in alkaline media. Two distinct forms of nickel hydroxides, α-Ni(OH)₂ and β-Ni(OH)₂, were synthesized through potential cycling within specific voltage ranges and subsequently evaluated for their catalytic performance. Carbon-based materials doped with nickel nanoparticles were used as catalytic substrates, and their suspensions were applied to glassy carbon electrode surfaces to create working electrodes. Electrochemical characterization, including polarization curve analysis and Tafel slope evaluation, was conducted to assess the catalytic efficiency and reaction kinetics. The results indicate that both hydroxide forms exhibit comparable catalytic activity, with β-Ni(OH)₂ showing slightly superior performance due to lower overpotential and a more favorable Tafel slope. The kinetic analysis confirmed a diffusion-controlled reaction mechanism for both forms, with β-Ni(OH)₂ demonstrating subtly enhanced reaction kinetics. These findings underline the significance of surface modification in optimizing nickel-based catalysts for HER and provide insights into the role of nickel oxidation states in catalytic processes.9th International Hydrogen Technologies Congress, 25-28 May 2025
Combined effects of the effective thermal conductivity and ash deposit thickness on the results of numerical simulations
No full textThe most important thermophysical property for heat transfer through the ash deposits, accumulated at the waterwalls of the pulverized coal-fired furnaces, is the effective thermal conductivity. It affects the values of the wall variables: heat flux, temperature, and emissivity, and furnace temperature. In numerical simulations, the values of the effective thermal conductivity are used in combination with the ash deposit thicknesses. The objective of this investigation was to find the combined effects of the effective thermal conductivity and deposit thicknesses on the results of numerical simulations. Three curves were formed on the basis of the data available in literature. For every curve, three thicknesses of the non-uniform ash deposits were determined on the basis of the base normal distribution. The thickness of every surface zone was determined as a product of the number obtained from the diagram which shows dependence of the mean wall flux vs. uniform thickness and corresponding thickness of the base distribution. The wall variables and flame temperatures were compared for the three values of the mean wall fluxes. The results showed that type of the curve did not influence the mean values of the wall variables and flame temperatures. The curves influenced the distribution of the wall variables very little. The maximal mean relative difference was obtained for the wall flux and it was less than 2%. The results indicates that the level of slagging can be defined by the ratio of the mean wall fluxes of the clean and wall covered by the ash deposit
Application of waste materials in green roofs
No full textGreen roofs are becoming increasingly popular as a sustainable architectural solution that provides numerous economic, environmental, and social benefits. Selecting a suitable substrate and drainage layers is important for having a sustainable green roof with good water retention and energy-saving potential, runoff water quality, and plant growth. There is a need to replace materials currently used in green roofs with more environmentally friendly products. Within such context, this paper discusses the application of different recycled and waste materials in green roofs and identifies what waste materials can be used in green roofs in Serbia. The use of locally available recycled materials can reduce the carbon footprint of green roofs, improve their life cycle, and reduce the cost of construction. This paper sheds light on the design of green roofs with better performance and reduced environmental impact.IOC2025 : 56th International October Conference on Mining and Metallurgy; October 22-25, 2025, Bor Lake, Serbia
Nanoemulsification synthesis and spark plasma sintering of ternary-substituted hydroxyapatite
No full textHydroxyapatite (HA) remains a leading candidate among bioceramic materials for
bone repair, owing to its high biocompatibility and close chemical resemblance to
natural bone. Nevertheless, its poor mechanical resilience continues to hinder its
widespread use. To address this limitation, ionic substitution at calcium lattice sites has
gained attention as a method to enhance HA’s structural and functional characteristics. In
this work, we report the successful synthesis of a novel ternary-substituted
hydroxyapatite with the composition (Ca,Sr,Ba)5(PO4)3(OH), produced via the Ouzo
nanoemulsification technique at room temperature and subsequently calcined at 700 °C
for 3 hours. X-ray diffraction analysis confirmed the formation of the apatite phase
without the presence of secondary phases. The resulting powders were densified using
spark plasma sintering, achieving near-theoretical density without phase decomposition.
Microstructural characterization demonstrated a dense and homogenous grain structure.
Mechanical testing indicated enhanced hardness and a Young’s modulus comparable to
conventional HA. Furthermore, immersion in simulated body fluid led to apatite
formation within 24 hours, indicating preserved bioactivity. These findings demonstrate
that co-substitution with Sr2+ and Ba2+ contributes to improved sinterability and
mechanical performance while retaining the material’s bioactivity, highlighting its
promise for use in bone repair and implant applications.16th ECerS Conference for Young Scientists in Ceramics, October 15-18, 2025, Novi Sad, Serbia