ABSTRACT The selective removal of polydimethylsiloxane (PDMS) coatings from nylon 6,6 airbag fabrics is essential for enabling circular reuse of high‐value technical textiles. In this study, a nonaqueous depolymerization method was developed using potassium hydroxide (KOH) as a catalyst in isopropyl alcohol (IPA) as the solvent, targeting siloxane bond exchange to cleave crosslinked PDMS networks. Among the solvents evaluated, IPA demonstrated optimal compatibility, enabling complete PDMS removal and efficient solvent recovery. KOH concentration emerged as a critical parameter, with 0.75 wt% resulting in effective depolymerization while minimizing the degradation of mechanical performance. Fourier‐transform infrared spectroscopy and scanning electron microscopy‐energy dispersive spectroscopy analyses confirmed the elimination of silicone residues and preservation of the nylon backbone. Mechanical and thermal characterizations demonstrated that key properties, including tensile strength, ductility, impact resistance, and heat deflection temperature (HDT), were retained after treatment. The proposed approach offers a scalable and fabric‐safe solution for the sustainable recycling of silicone‐coated textiles from end‐of‐life airbag materials, without the need for additional reinforcement or polymer modification. Key Points Applies siloxane exchange chemistry to enable selective depolymerization of silicone coatings. Combines polymer reaction engineering with solvent recovery strategies for scalable recycling. Connects materials chemistry and environmental engineering to advance circular use of airbag textiles.

ABSTRACT Elevated nitrate levels in surface and groundwater is a critical environmental problem, leading to devastating consequences for human health and natural ecosystems. This paper presents novel organosilica adsorbents that exhibit high efficiency in removing nitrates from contaminated water. Amino‐functionalized porous materials were synthesized via grafting and sol‐gel methods using various precursors. The sol–gel synthesis was carried out without tetraethoxysilane to increase the contents of amino groups, which act as adsorption sites for nitrate ions. Neither an acidic nor a basic catalyst was added to the reaction mixture. The sol–gel materials had higher contents of amino groups than the grafted ones (3.47–4.01 and 0.48–0.99 mmol/g, respectively). The amino groups were then converted to hydrochloride. It was found that even in the absence of a surfactant, the resulting material had a BET surface area of up to 217 m 2 /g, ensuring easy accessibility of surface amino groups for nitrate ions. The organosilica materials demonstrated excellent adsorption capacity for nitrate ions, which reached 3.68–4.04 mmol/g. These values exceed the corresponding literature data. The developed materials maintain high efficiency over a wide temperature range. They are recyclable and can be reused after regeneration. Biological testing confirmed significant inhibition of algae growth in contaminated water after treatment. The simplicity and environmental friendliness of production of these adsorbents using inexpensive and readily available chemicals, combined with their high adsorption efficiency, make them promising materials for removing nitrates from water to acceptable levels. Summary Effective organosilica adsorbents for removing nitrates from contaminated water were synthesized using an environmentally friendly method from inexpensive precursors. They demonstrated high adsorption capacity for nitrate ions, exceeding most published data under a wide range of conditions. The low cost of the developed materials and their recyclability suggest their potential for use in water purification.

Introduction: The availability of water supply infrastructure is a key determinant of spatial development. Insufficient infrastructure can trigger a range of adverse processes, including weaker economic performance, deteriorating hygienic and sanitary conditions, reduced quality of life, deruralization, as well as internal and external migration. Consequently, this represents a significant barrier to sustainable development. Regionalization of water supply systems is increasingly recognized as a viable solution to these challenges, with numerous successful examples across the European Union and the wider region. Regional systems provide substantial economic benefits and enable a reliable water supply for non-urban populations. The Republic of Srpska faces persistent difficulties in this regard, as much of its rural territory and a considerable number of underdeveloped municipalities remain uncovered by hydrotechnical infrastructure. Aim: This study aims to analyze the current state of water supply infrastructure and propose measures for optimizing the system in the Republic of Srpska through the establishment of regional supply networks. Materials and Methods: During the research, all scientific principles necessary to ensure objectivity and methodological rigor were observed. Relevant scholarly literature in the field, along with official spatial planning documentation pertaining to the study area, was thoroughly consulted. Analytical and synthetic methods were applied in processing the collected data, enabling the formulation of well-founded conclusions. Statistical methods were employed for the analysis of demographic data and water supply indicators, while the results of the research were presented through cartographic techniques. Results: Through the research findings, regions with the greatest shortage of water supply connections were identified, and planning measures for addressing the issue were proposed. Conclusion: The analysis of water supply infrastructure in the Republic of Srpska reveals significant spatial and infrastructural disparities among local government units. Strengthening water supply infrastructure and improving the efficiency of existing systems are essential to achieving sustainable and balanced spatial development. These objectives can be most effectively realized through the regionalization of water supply systems.

Introduction: In this paper, the current state of tourist attractions (values), facilities, and their potential in the territory of the city of Niš is analyzed, as well as their projected potential state in case of undertaking measures and activities that would result in greater attractiveness of the city area of Niš. The introductory part of the paper deals with the presentation and description of chosen natural and cultural tourist values and accompanying facilities (traffic infrastructure, hotels, tourist information centers) in GIS software, which can provide a clear visual representation of tourist values. Aim: The aim of this research is to use Geographic Information System (GIS) methods to analyze tourist attractions, facilities, and their potential within the territory of the city, identify spatial patterns, and visualize tourist resources, which can provide information on the accessibility of tourist assets and define recommendations for improving the tourist offer. Materials and Methods: The analytical–synthetic, cartographic, and geospatial analysis methods were applied in the paper. As a relevant parameter in mapping tourist facilities, the directions of tourist movement during visits to attractions and sites were taken into account. Results: The results of the research should give us an insight into the identification of less accessible attractions, the density of facilities, and spatial distribution, and the measures and activities that should be taken to improve the overall tourist offer of the city of Niš. Conclusion: The research confirms that GIS methodology has significant application in the analysis of tourism potential and facilities and provides an effective tool for the cartographic visualization of tourist assets and the creation of tourist routes, while the research results can contribute to further strategic tourism planning in the city of Niš.

Introduction: Accessibility of healthcare facilities is a key indicator of the functionality of the public health system, and its spatial assessment enables informed decision-making in planning the healthcare network. The municipality of Bujanovac, as a border and predominantly rural area in southern Serbia, faces significant infrastructural and demographic challenges that may affect the quality and availability of healthcare services. Aim: The aim of this research is to conduct a comprehensive assessment of the spatial accessibility of healthcare facilities within the municipality using Geographic Information Systems (GIS) methods, to identify critical zones with limited access, and to define recommendations for improving spatial coverage of healthcare services. Materials and Methods: The methodological framework involves the integration of vector and raster data (administrative boundaries, settlement networks, road infrastructure, locations of healthcare facilities, demographic indicators, and a digital elevation model) and the application of network analysis methods. Time accessibility zones (5, 10, and 15 minutes of driving distance) around the nearest healthcare facility were created, along with an analysis of their overlap with the spatial distribution of the population. Results: The results indicate that a significant number of settlements, especially in hilly and mountainous areas, remain outside the optimal time accessibility zones. Based on the findings, interventions have been proposed, including the establishment of additional clinics, the deployment of mobile healthcare teams, and improvements to transportation connectivity, to reduce spatial inequalities in access to healthcare. Conclusion: The study confirms that GIS methodology provides a reliable and efficient tool for quantitative and visual assessment of accessibility and can significantly contribute to strategic planning and the optimization of the healthcare network at the local level.

Introduction: Open-area fires are a major environmental problem and, in most cases, are caused by human negligence. They are often limited in scope and intensity, but can spread and cause serious consequences for natural ecosystems and endanger the lives of people and animals. The municipality of Aleksinac faces similar challenges, as open fires are frequently recorded in its territory. Aim: The aim of the study was to analyse the spatial and temporal distribution of open-area fires and to observe patterns of their occurrence and spatial grouping. Materials and Methods: Fire data recorded by MODIS sensors were downloaded from NASA’s FIRMS platform. Subsets of historical fire locations, registered between January 1, 2001, and July 9, 2025, were downloaded in vector data format. The spatial and temporal analysis was carried out using the QGIS and PAST programmes. Results: The highest number of registered fires in one year was recorded in 2007, when a total of 31 fires were registered. A large number of fires were the result of low rainfall and high air temperatures. In periods when the average monthly air temperatures were lower and the monthly amount of precipitation was above the multi-year average, the number of fires was significantly lower. The spatial analysis identified 10 clusters, 5 of which are located in the South Morava Valley. The largest number of fires was registered in Cluster 4, which included the areas west and northwest of Aleksinac, and which spatially coincided with the most intense hotspot of fire occurrence. Conclusion: Meteorological conditions play a key role in the occurrence and spread of fires in the area of the municipality of Aleksinac, while the frequent fires in October and March are a consequence of increased agricultural activity. Non-irrigated arable land has the highest risk of open-area fires.

Introduction: Potamopyrgus antipodarum (J. E. Gray, 1843) is an invasive freshwater and brackish water snail native to New Zealand, spreading across Europe since the 19th century. The first records in Bosnia and Herzegovina were published in 2005 in the Krivaja River. Later, the presence of this invasive snail species was also recorded in several springs of the rivers Bosna and Vrbas. Morphometric characteristics and fecundity are very important for a species’ adaptability and reproductive potential. These parameters have not previously been investigated in Bosnia and Herzegovina’s populations. Aim: To determine shell dimensions and the number of embryos of P. antipodarum from a selected spring on the right bank of the Vrbas River in Banja Luka, and to examine a possible relationship between shell size and fecundity. Materials and Methods: From the total number of individuals, 30 were randomly selected for morphometric analysis. After photographing each individual with a Leica EZ4D stereomicroscope, the following parameters were measured: total shell height, aperture height, total shell width, aperture width, and spire height above the aperture. Sex and number of embryos were determined for the same individuals. Descriptive statistics were performed. Pearson’s correlation coefficient (r) was calculated between total shell height and the number of embryos. Results: The average value of total shell height was 4.03 ± 0.30 mm, total shell width 2.14 ± 0.17 mm, aperture height 1.49 ± 0.13 mm, and aperture width 1.28 ± 0.10 mm. The number of embryos varied from 13 to 36. The lowest coefficient of variation was observed for total shell height (7.44%), and the highest for the number of embryos (28.49%). A moderate positive correlation was found between shell size and number of embryos (r = 0.54), which suggests that larger individuals produce more embryos. Conclusion: The mean shell parameters and number of embryos fall within the known range. Fecundity of this invasive species increases with shell size.

Introduction: Classical orthogonal polynomials such as the Legendre, Laguerre, Hermite, and Chebyshev polynomials have a wide range of applications across various domains of science and engineering. Aim: The aim of this research paper is to present selected recent developments in the theory of orthogonal polynomials, with particular emphasis on their analytical properties and their role in approximation theory. Methods: The study employs a combined quantitative-qualitative research methodology. It is based on the analysis of relevant scientific literature, from which data significant to the subject matter were collected, interpreted, and systematically examined. Results: The results indicate that contemporary research in probability theory, graph theory, coding theory, and related areas increasingly relies on the theory of orthogonal polynomials. This paper provides a theoretical analysis of the connection between orthogonal polynomials and their applications in specific computational problems. Fundamental properties of these polynomials are presented and illustrated through selected examples that contribute to a clearer understanding of their structure and practical relevance. Conclusion: The approximation of the transfer function of a low-pass filter can be achieved through a straightforward adaptation of orthogonal Jacobi polynomials. Furthermore, Gaussian quadrature represents a powerful numerical technique for the approximation of definite integrals, utilizing optimally chosen nodes and weight functions to achieve high accuracy with minimal computational effort. Orthogonal polynomials thus serve as a significant link between pure mathematics and engineering disciplines, highlighting the importance of further study on their properties and applications.

Introduction: Natural resources are often the basis for creating additional value in the economy of a region. In the case of the Niš region, they have a special importance to agriculture, tourism, the processing industry, and even to the energy sector, and despite the great potential, many resources remain underutilized or managed inefficiently. Aim: The objective of this paper is to present and evaluate the natural resources of the Niš region, identify their impact on economic development, and offer guidelines for their more efficient and sustainable use. Materials and Methods: The methodological approach involves the analysis of available statistical data, scientific literature, as well as relevant strategic documents of the Republic of Serbia. By combining desk analysis and a comparative approach, we will try to offer a complete insight into the state of the natural resources of this region and the possibilities of their economic valorization. Results: During the analysis, it was found that the main obstacles to development are inefficient management, lack of strategic planning, insufficient investment in infrastructure, and outdated technology. The problem of neglected agricultural areas, insufficiently developed ecotourism and spa tourism, as well as inadequate use of geothermal sources, is particularly pronounced. The decrease in the number of inhabitants, as well as the outflow of young people from the region, also contribute to these challenges. Conclusion: The Niš region has extremely valuable and diverse natural resources that represent one of the key potentials for its economic and social development. Fertile lands, numerous watercourses, thermal and mineral waters, forest area, and a rich biodiversity base provide the basis for the development of agriculture, tourism, energy, and the processing industry.

ABSTRACT Dengue remains a major public health threat in tropical and subtropical regions. We develop a general human–vector SEIR–SEI optimal‐control framework that integrates four time‐dependent interventions: public awareness/behavioral protection, , enhanced clinical management , adulticide spraying , and larval‐source reduction/larvicide . The controls act by reducing effective human–vector contact, increasing human recovery, increasing adult mosquito mortality, and suppressing vector recruitment, respectively. The objective is to minimize a weighted sum of infectious burden in humans and vectors and the quadratic costs of implementation over a finite horizon, subject to epidemiological dynamics and standard control bounds 0 ≤ u i ( t ) ≤ 1. Using Pontryagin's Maximum Principle, we derive the necessary conditions for optimality and solve the resulting two‐point boundary value problem numerically. Numerical simulations conducted in MATLAB, calibrated with real data from Bangladesh, perform uncertainty and sensitivity analyses around the basic reproduction number and key transmission, and control parameters reveal that Strategy‐4, which includes public awareness, treatment, and insecticide spraying (), is the most effective and cost‐efficient approach. This strategy reduces the time to disease elimination from over 100 days to approximately 74.7 days, achieving a 72.66% faster reduction than natural decay. The findings demonstrate that the proposed control strategies can significantly curb the progression of dengue and support targeted public health interventions to manage outbreaks effectively.