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Towards Circularity in Serbian Mining: Unlocking the Potential of Flotation Tailings and Fly Ash
No full textThis paper examines sustainable industrial practices in Serbia, particularly in the mining and energy sector, focusing on the potential of flotation tailings and fly ash, as materials with the largest share in disposed waste in Serbia in 2023 (95%). It highlights the environmental challenges of mining waste and explores innovative approaches to waste management within the circular economy framework. The study analyzes the current state of mining waste in Serbia, particularly in copper mining regions in the east of the country. It discusses the potential for metal recovery from waste and its reuse in various industries. The research also investigates the use of fly ash from thermal power plants as a valuable resource in the construction industry and other sectors. The paper reviews existing initiatives and legislation in Serbia in order to promote sustainable mining practices and waste utilization. By presenting case studies and potential applications, the study demonstrates how implementing circular economy principles in the mining sector can contribute to environmental protection, resource conservation, and economic growth in Serbia. The comprehensive overview of the current state in Serbia provides a solid foundation for establishing a higher degree of circularity in the mining and energy sectors
Distribution of radionuclides and associated radiological risk assessment of soils from Niška Banja, Serbia
No full textThe activity concentrations of 226Ra, 232Th and 40K were determined in 43 soil samples collected from 0 to 10 cm and 10 to 50 cm depths of Niška Banja region, Serbia, using a low background gamma spectroscopy with 3″ × 3″ NaI(Tl) scintillation detector. The mean absorbed dose rate of 0–10 cm and 10–50 cm depth soil were 66.1 and 60.4 nGy/h, respectively which was close to UNSCEAR worldwide value. The radium equivalent and annual effective dose effect were lower than the permissible level. Therefore, there is no significant radiological risk from the soil to residents living in this region
Goat milk powders enriched with grape pomace seed extract: Physical and techno-functional properties
No full textThis study aimed to evaluate the physical (particle size and ζ-potential) and techno-functional properties (emulsifying and foaming) of goat milk powders enriched with grape pomace seed extract (TME), as promising food ingredients in the formulation of functional food. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Raman spectroscopies, along with advanced chemometric tools were employed as well as Scanning Electron Microscopy (SEM) for analyzing TME powders. All powders exhibited a unimodal particle size distribution and ζ-potential values more negative than −36 mV. ATR-FTIR and Raman spectroscopies combined with principal component analysis (PCA) demonstrated distinct separation among skimmed goat milk (M), thermally treated skimmed goat milk (TM), and TME powders in different spectral regions (amide I, II, III, and fingerprint region). This separation resulted from the applied thermal treatment, the presence of phenolic compounds and their complexes with goat milk proteins, and the formation of Maillard reaction products. SEM analysis confirmed the different morphology and shapes of M, TM and TME powders. The 0.1% solutions of M, TM and TME exhibited good emulsifying properties (emulsion activity index and emulsion stability index) but showed poor foaming properties, except for the M sample. Solution concentrations higher than 0.1% for all samples (0.5% and 1.0%) displayed poor techno-functional properties. In summary, a schematic representation of the arrangement of casein micelles in 0.1% M, TM and TME samples, on oil/water and air/water surfaces was provided. The production of TME powders represents an innovative strategy for waste recovery in the production of functional food ingredients with good emulsifying properties
High Pressure Densities and Derived Thermodynamic Properties of Pure (1R)-(+)-α-Pinene, (1S)-(−)-β-Pinene, and Linalool: Experiment and Modeling
No full textTerpenes usually found in plants have a wide range of applications, especially as additives in various types of fuels, and most recently in the aviation industry, where they can be blended with jet fuels or kerosene. In this work, the densities of pure terpenes (1R)-(+)-α-pinene, (1S)-(−)-β-pinene, and linalool were measured over the temperature range T = (293.15 to 413.15) K and at high pressures p = (0.1 to 60) MPa. The experimental density data were fitted by the modified Tammann-Tait equation where the absolute average percentage deviation between measured and calculated densities was less than 0.02%, the percentage maximum deviation was less than 0.2%, and the average percentage deviation was less than 0.02% for all three measured terpenes. The obtained parameters were used to determine isothermal compressibility (κT), isobaric thermal expansivity (αp), internal pressure (pint), and the difference between specific heat capacity at constant pressure (cp) and constant volume (cv). Furthermore, the PC-SAFT model was applied for liquid density prediction at high pressures. Derived thermodynamic properties such as isothermal compressibility and isobaric thermal expansivity increase as temperature increases and decrease with pressure for all of the studied compounds.Published as part of Journal of
Chemical & Engineering Data virtual special issue “Proceedings of PPEPPD 2023”
Chitosan-pectin multilayer coating with anthocyanin grape dye as pH indicating wound dressing: Synthesis and characterization
No full textEnvironmentally benign pH-indicating wound dressing comprised of carbohydrates chitosan (CH) and pectin (P), and anthocyanin grape (AG) dye is created via layer-by-layer assembly. Cotton fabric coated with eight bilayers of (CH-AG)4/(P-AG)4 deposited 1.97 % AG-dye. It exhibited a visible and immediate color change from pink to violet-blue while increasing its pH value from 6 to pH 7, matching the turning pH point of healing into an infected wound. Color transition of AG-dye in water-based buffers, tested by VIS-spectroscopy, shows the same color change when the pH value increased from 6 to 7. This coating imparts excellent antimicrobial activity against Gram-positive bacteria Staphylococcus aureus and yeast Candida albicans, moderate antibacterial activity against Gram-negative Escherichia coli bacteria, and no cytotoxicity on human fibroblast cells (MRC-5). This research proposes a sustainable, low-cost, and simple method for obtaining smart wound dressing that provides real-time monitoring of the wound pH
Two-phase electro-magneto-fluid dynamics model and its computational fluid dynamics implementation
No full textIn this work, we present a two-phase electro-magneto-fluid dynamics (EMFD) model that merges electromagnetics and fluid dynamics. The model is suitable for use in computational fluid dynamics (CFD) software and was incorporated into OpenFOAM® after deriving appropriate equations that bypassed certain limitations of the software. Currently, there is lack of even single-phase EMFD models that can be incorporated into CFD software; however, simpler models from electrohydrodynamics (EHD) and magnetohydrodynamics (MHD) are being implemented although they have certain approximations that can limit their applicability. We conclude that the derived EMFD model is applicable, and show its quality by implementing it and analyzing the results. We use cases with a droplet and the electrospinning process for verification. The drop deformations obtained were closer to analytical predictions than in the literature for two EHD models, but some oscillations were observed. We compared one simulation to the prediction of an analytical equation from MHD, and good agreement was shown. Finally, we simulate the electrospinning process, and the results were very close to the analytical predictions. We conclude that the implementation can be used for both EHD and MHD cases.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in S. A. Bošković & B. Bugarski, Phys. Fluids 36, 022019 (2024) and may be found at [https://doi.org/10.1063/5.0190651].Peer reviewed manuscript: [https://technorep.tmf.bg.ac.rs/handle/123456789/7288
Microstructure, mechanical and corrosion properties of anodized ultrafine-grained titanium based materials for medical application
No full textBroccoli, Amaranth, and Red Beet Microgreen Juices: The Influence of Cold-Pressing on the Phytochemical Composition and the Antioxidant and Sensory Properties
No full textThe aim of this study was to analyze in detail the phytochemical composition of amaranth (AMJ), red beet (RBJ), and broccoli (BCJ) microgreens and cold-pressed juices and to evaluate the antioxidant and sensory properties of the juices. The results showed the presence of various phenolic compounds in all samples, namely betalains in amaranth and red beet microgreens, while glucosinolates were only detected in broccoli microgreens. Phenolic acids and derivatives dominated in amaranth and broccoli microgreens, while apigenin C-glycosides were most abundant in red beet microgreens. Cold-pressing of microgreens into juice significantly altered the profiles of bioactive compounds. Various isothiocyanates were detected in BCJ, while more phenolic acid aglycones and their derivatives with organic acids (quinic acid and malic acid) were identified in all juices. Microgreen juices exhibited good antioxidant properties, especially ABTS•+ scavenging activity and ferric reducing antioxidant power. Microgreen juices had mild acidity, low sugar content, and good sensory acceptability and quality with the typical flavors of the respective microgreen species. Cold-pressed microgreen juices from AMJ, RBJ, and BCJ represent a rich source of bioactive compounds and can be characterized as novel functional products
Quantitative Crystal Structure Analysis of A Selected Spirohydantoin Derivative
No full textAn analysis of structural features of new compounds with multiple hydrogen-bond donating and
accepting groups can enhance our understanding of development of supramolecular assemblies
with potential for application in life sciences. Using the quantum chemical calculations,
formation of the crystal structure of cyclohexane-5-spirohydantoin bearing a 4-tert-butylbenzoyl
group (Fig. 1) was analysed in terms of a number of dimeric motifs associated with
intermolecular interactions. The crystal structure retains the motif commonly found in hydantoin
derivatives, where two molecules related by inversion are linked by a pair of N‒H‧‧‧O
hydrogen bonds [1]. This motif is involved in two types of double chains, which further form a
layer. Together with the dispersion interactions (π‒π and hydrophobic), C‒H‧‧‧O interactions
act as the source of attraction between the layers. Intermolecular interactions were also
investigated using the Hirschfield surface analysis, enabling to additionally estimate quantitative
contributions of intermolecular interactions to the crystal packing
Comparative Analysis of Electrokinetic Properties of Periodate- and TEMPO-Oxidized Regenerated Cellulose Fabric Functionalized with Chitosan
No full textThe electrokinetic properties of materials give useful insight into the behavior of surfaces in contact with liquids and other compounds and their quantification is a powerful tool to predict their behavior during further processing and application, especially in textile materials. In this work, we perform a comparative analysis of influence of the two most common selective oxidative protocols for viscose (regenerated cellulose) fabrics on subsequent functionalization with chitosan, and cellulose fabrics’ electrokinetic properties, zeta potential in a pH range of approx. 3–10, and isoelectric point (IEP). For oxidation before deposition of chitosan, sodium periodate and 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO) were used. The content of functional groups in oxidized cellulose fabric (carboxyl and carbonyl groups) was determined by titration methods, while amino functional groups’ availability in samples with chitosan was determined using the CI acid orange 7 dye absorption method. This study reveals that the periodate oxidation (PO) of cellulose is more effective for binding chitosan onto material, which gave rise to higher availability of amino groups onto cellulose/chitosan material, which also influenced the shift in zeta potential curve towards positive values at a pH below 5. Analysis of a relationship between zeta potential increase at pH 4.4 and amino groups’ amount measured using absorption of CI acid orange 7 dye at pH 4.4 revealed dependency that can be fitted linearly or exponentially, with the latter providing the better fit (R2 = 0.75)