Volume 9, 2025

Table of contents

List of Reviewers
Materials Science

ADVANCED DIGITAL IMAGE PROCESSING FOR MATERIAL EVALUATION IN NUCLEAR APPLICATIONS

Ondřej Pašta, Jaroslav Knotek, Jan Blažek, Marcin Kopeć

DOI: 10.21175/RadProc.2025.01

Received: 5 SEP 2025, Reviews sent: 17 NOV 2025, Received revised: 2 DEC 2025, Accepted: 10 DEC 2025, Published online: 24 DEC 2025

| | | Full Text (PDF)

The integration of digital image processing (DIP), neural networks, and artificial intelligence (AI) is transforming materials science by enabling automated, high-resolution analysis of microscopic structures and supporting applications across nuclear research. At Research Centre Řež (CVR), DIP and AI have improved efficiency and reproducibility in workflows such as the classification of microstructural precipitates—both manufacturing- related secondary phase particles and radiation-induced precipitates—whose morphology and distribution affect key mechanical properties. These methods are also applied to the structural assessment of biological shielding concrete, where DIP detects and quantifies crack development, complementing traditional non-destructive testing. In fuel inspections and post-irradiation examinations, DIP enhances video analysis and microscopy, reducing manual bias while ensuring consistent evaluation of cladding and structural components. Overall, DIP technologies developed at CVR strengthen long-term operation (LTO) strategies in nuclear energy and offer versatile solutions for other sectors requiring precise microstructural or surface characterization.
  1. J.T. Busby, R.K. Nanstad, R.E. Stoller, Z. Feng, D.J. Naus, “Materials Degradation in Light Water Reactors: Life After 60?”, Oak Ridge National Laboratory, 2008.
    https://doi.org/10.2172/938766
  2. L.J. Bond, “Moving Beyond NDE to Proactive Management of Materials Degradation”, in Proc. ASME Pressure Vessels and Piping Conf. (PVP), 2011, pp. 205-214.
    https://doi.org/10.1115/PVP2010-26174
  3. T.S. Byun, D.A. Collins, T.G. Lach, E.L. Carter, “Degradation of impact toughness in cast stainless steels during long-term thermal aging”, J. Nucl. Mater., vol. 542, 152524, 2020.
    https://doi.org/10.1016/j.jnucmat.2020.152524
  4. O.Y. Chernousenko, T.V. Nikulenkova, A.H. Nikulenkov, “Milestones of Implementation of Aging Management for NPP Components”, Bull. NTU “KhPI”. Ser.: Power & Heat Eng. Proc. Equip., vol. 9 (1181), pp. 85–89, 2016.
    https://doi.org/10.20998/2078-774X.2016.09.12
  5. D. Plašienka, J. Knotek, M. Kopeć, M. Malá, J. Blažek, “Measurement of nuclear fuel assembly’s bow from visual inspection’s video record”, Nucl. Eng. Des., vol. 55, no. 4, pp. 1485-1494, 2023.
    https://doi.org/10.1016/j.net.2022.12.033
  6. H. Ebrahimgol, M. Aghaie, A. Zolfaghari, A. Naserbegi, "A novel approach in exergy optimization of a WWER1000 nuclear power plant using whale optimization algorithm", Ann. Nucl. Energy, vol. 145, p. 107540, 2020.
    https://doi.org/10.1016/j.anucene.2020.107540
  7. I. Maruyama et al., “Radiation-induced alteration of sandstone concrete aggregate”, J. Nucl. Mat., vol. 583, 154547, 2023.
    https://doi.org/10.1016/j.jnucmat.2023.154547
  8. ICIC – International Committee on Irradiated Concrete. [Online]. Available: https://icic2023.ornl.gov [Accessed: Sep. 24, 2025].
  9. T. Motta, A. Couet, R.J. Comstock, “Corrosion of zirconium alloys used for nuclear fuel cladding”, Annu. Rev. Mater. Res., vol. 45, pp. 311–343, 2015.
    https://doi.org/10.1146/annurev-matsci-070214-020951
  10. S. Zhao, G. Ran, Y. Guo, Q. Han, S. Liu, F. Gao, “Study on the mechanism of helium platelets formation at low temperatures in SiC from the perspective of atomic diffusion”, J. Nucl. Mater., vol. 542, p. 152507, 2020.
    https://doi.org/10.1016/j.jnucmat.2020.152507
  11. G. Van Rossum, F.L. Drake, Python 3 Reference Manual, CreateSpace, 2009.
  12. M. Abadi et al., TensorFlow: Large-Scale Machine Learning on Heterogeneous Systems, 2015
    arXiv:1603.04467
  13. A. Leenaers et al., “Post-irradiation examination of AlFeNi cladded U3Si2 fuel plates irradiated under severe conditions”, J. Nucl. Mater., vol. 375, no. 2, pp. 243–251, 2008.
    https://doi.org/10.1016/j.jnucmat.2008.01.013
  14. P. Mishra, V. Karthik, P.K. Shah, “Post Irradiation Examination of Fuel”, in Nuclear Fuel Cycle, Springer, 2023, pp. 185–212.
    https://doi.org/10.1007/978-981-99-0949-0_6
  15. J. Li, W. Xu, D. She, H. Xie, Z.-H. Liu, L. Shi, “Review of the development and application of high flux reactors”, Nucl. Sci. Tech., vol. 36, 227, 2025.
    https://doi.org/10.1007/s41365-025-01808-y
  16. J.-W. Cho, Y. Choi, K. Jeong, J.-C. Shin, “Measurement of nuclear fuel rod deformation using an image processing technique”, Nucl. Eng. Technol., vol. 43, no. 2, pp. 133–139, 2011.
    https://doi.org/10.5516/NET.2011.43.2.133
  17. F. Shadmehri, S.V. Hoa, “Digital Image Correlation Applications in Composite Automated Manufacturing, Inspection, and Testing”, Appl. Sci., vol. 9, no. 13, 2719, 2019.https://doi.org/10.3390/app9132719
  18. P. Murray, G. West, S. Marshall, S. McArthur, “Automated in-core image generation from video to aid visual inspection of nuclear power plant cores”, Nucl. Eng. Des., vol. 300, pp. 57–66, 2016.
    https://doi.org/10.1016/j.nucengdes.2015.11.037
  19. M. Devereux, P. Murray, G. West, S. Buckley-Mellor, G. Cocks, C. Lynch, A. Fletcher, “Automated analysis of AGR fuel channel inspection videos”, presented at 6th EDF-Energy Nuclear Graphite Conference, Kendal, UK, Oct. 2018.
    [Online]. Available: [https://pure.strath.ac.uk/ws/portalfiles/portal/87 986003/Devereux_etal_EDF_2018_Automated_a nalysis_of_AGR_fuel_channel_inspection.pdf]
    [Accessed: Sep. 24, 2025]
  20. J. Knotek, J. Blažek, M. Kopeć, “Simulating nuclear fuel inspections: Enhancing reliability through synthetic data”, Nucl. Eng. Technol., vol. 57, no. 8, 103571, 2025.
    https://doi.org/10.1016/j.net.2025.103571
Ondřej Pašta, Jaroslav Knotek, Jan Blažek, Marcin Kopeć, "Advanced digital image processing for material evaluation in nuclear applications", RAD Conf. Proc., vol. 9, 2025, pp. 1-6; http://doi.org/10.21175/RadProc.2025.01
Other topic

NON-LINEAR VISCOELASTIC BEAMS WITH TWO-DIMENSIONAL MATERIAL INHOMOGENEITY: A LONGITUDINAL FRACTURE ANALYSIS

Victor Rizov

DOI: 10.21175/RadProc.2025.02

Received: 4 AUG 2025, Reviews sent: 16 SEP 2025, Received revised: 6 OCT 2025, Accepted: 15 OCT 2025, Published online: 20 JAN 2026

| | | Full Text (PDF)

This paper is focussed on analysis of longitudinal fracture in non-linear viscoelastic beam structures with two- directional continuous material inhomogeneity (the material properties change continuously in both width and thickness directions). The viscoelastic model that is used for treating the mechanical behaviour of the beam represents a combination of four linear and two non-linear springs and dashpots. The model is under strains which change with time. The material properties involved in the constitutive law are distributed continuously in the cross-section. The strain energy release rate (SERR) is derived. For this purpose, the curvatures are determined by using the equilibrium equations. The method of the J-integral confirms the correctness of the SERR solution.
  1. K. Li, M. Zhang, Z. Zhang, P. Jin, Y. Wang, W. Yan, L. Zhu, D. Zhang, L. Murr, “High performance realization of functionally graded materials based on integrated optimal design and additive manufacturing: A reviewˮ, International Materials Reviews, vol. 70, no. 6, pp. 497-547, 2025.
    https://doi.org/10.1177/09506608251354889
  2. I.M. El-Galy, B.I. Saleh, M.H. Ahmed, “Functionally graded materials classifications and development trends from industrial point of view", SN Appl. Sci., vol. 1, p. 1378, 2019.
    https://doi.org/10.1007/s42452-019-1413-4
  3. Z. Hu, Z. Ma, L. Yu, Y. Liu, “Functionally graded materials with grain-size gradients and heterogeneous microstructures achieved by additive manufacturingˮ, Scripta Materialia, vol. 226, 115197, 2023.
    https://doi.org/10.1016/j.scriptamat.2022.115197
  4. Q. Chen, J. Lai, Y. Ye, Y. Tian, S. Guo, J. Zhang, “A simple and effective strategy for WCu functionally graded materials with continuous gradientˮ, International Journal of Refractory Metals and Hard Materials, vol. 128, 106974, 2025.
    https://doi.org/10.1016/j.ijrmhm.2024.106974
  5. H.S. Hedia, S.M. Aldousari, A.K. Abdellatif, N.A. Fouda, “New design of cemented stem using functionally graded materials (FGM)”, Biomed. Mater. Eng., vol. 24, no. 3, pp. 1575-1588, 2014.
    https://doi.org/10.3233/BME-140962
  6. N. Van Thinh, H. Van Tung, “Free Vibration and Dynamical Analyses of FGM Plates with Porosity and Tangential Edge Constraintsˮ, J. Vib. Eng. Technol., vol. 12, pp. 5291–5305, 2024.
    https://doi.org/10.1007/s42417-023-01205-y
  7. Vu Thanh Long, Hoang Van Tung, “Thermo-torsional buckling and postbuckling of thin FGM cylindrical shells with porosities and tangentially restrained edgesˮ, Mechanics Based Design of Structures and Machines, vol. 51, no. 12, pp. 7056-7075, 2023.
    https://doi.org/10.1080/15397734.2022.2084752
  8. N. Van Thinh, H. Van Tung, “Nonlinear vibration of geometrically imperfect CNT-reinforced composite cylindrical panels exposed to thermal environments with elastically restrained edgesˮ, Acta Mech, vol. 235, pp. 1147–1164, 2024.
    https://doi.org/10.1007/s00707-023-03791-0
  9. L. Tokova, A. Yasinskyy, C.-C. Ma, “Effect of the layer inhomogeneity on the distribution of stresses and displacements in an elastic multilayer cylinder”, Acta Mechanica, vol. 228, pp. 2865-2877, 2017.
    https://doi.org/10.1007/s00707-015-1519-8
  10. K. Bousmaha, S. A. Belalia, S. M. Chorfi, A. Tounsi, M. A. Al-Osta, A. E. Alluqmani, “On the dynamic behavior of plates made of porous advanced materials reinforced with carbon nanotubes using a p-version of finite element method”, Mechanics Based Design of Structures and Machines, pp. 1–30, 2025.
    https://doi.org/10.1080/15397734.2025.2534679
  11. A. Tounsi, Z. Belabed, F. Bounouara, M. Balubaid, S.R. Mahmoud, A.A. Bousahla, A. Tounsi, “A finite element approach for forced dynamical responses of porous FG nanocomposite beams resting on viscoelastic foundations”, Int. J. Struct. Stab. Dyn., 2650078, 2024.
    https://doi.org/10.1142/S0219455426500781
  12. R. M. Mahamood, E. T. Akinlabi, “Future Research Direction in Functionally Graded Materials and Summary,” in Functionally Graded Materials. Topics in Mining, Metallurgy and Materials Engineering, Springer, Cham, 2017.
    https://doi.org/10.1007/978-3-319-53756-6_6
  13. V. Rizov, “Delamination analysis of inhomogeneous viscoelastic beam of rectangular section subjected to torsion”, Coupled Systems Mechanics, vol. 12, no. 1, pp. 69-81, 2023.
    https://doi.org/10.12989/csm.2023.12.1.069
  14. V. Rizov, “Effects of Periodic Loading on Longitudinal Fracture in Viscoelastic Functionally Graded Beam Structures”, J. Appl. Comput. Mech., vol. 8, no. 1, pp. 370–378, 2022.
    https://doi.org/10.22055/JACM.2021.37953.3141
  15. Z.-H. Wang, L. Zhang, L.-C. Guo, “A viscoelastic fracture mechanics model for a functionally graded materials strip with general mechanical properties,” European Journal of Mechanics - A/Solids, vol. 44, pp. 75-81, 2024.
    https://doi.org/10.1016/j.euromechsol.2013.10.008
  16. M. Ciavarella, A. Papangelo, R. McMeeking, “Transient and steady state viscoelastic crack propagation in a double cantilever beam specimen”, International Journal of Mechanical Sciences, vol. 229, 107510, 2022.
    https://doi.org/10.1016/j.ijmecsci.2022.107510
  17. F. Pan, W. Li, B. Wang, X. Zhang, “Viscoelastic fracture of multiple cracks in functionally graded materials”, Computer Methods in Applied Mechanics and Engineering, vol. 198, no. 33-36, pp. 2643-2649, 2009.
    https://doi.org/10.1016/j.cma.2009.03.005
  18. D. Broek, Elementary engineering fracture mechanics, Springer, 1986.
Victor Rizov, "Non-linear viscoelastic beams with two-dimensional material inhomogeneity: A longitudinal fracture analysis", RAD Conf. Proc., vol. 9, 2025, pp. 7 - 12; http://doi.org/10.21175/RadProc.2025.02
Other topic

ANALYSIS OF MULTIPLE DELAMINATION IN VISCOELASTIC MULTILAYERED BEAMS WITH RECTANGULAR SECTION SUBJECTED TO PURE TORSION

Victor Rizov

DOI: 10.21175/RadProc.2025.03

Received: 4 AUG 2025, Reviews sent: 16 SEP 2025, Received revised: 6 OCT 2025, Accepted: 15 OCT 2025, Published online: 20 JAN 2026

| | | Full Text (PDF)

The properties of continuously inhomogeneous materials depend on the location. This paper is focussed on the problem of multiple delamination in viscoelastic multilayered rectangular beams under loading that induces torsion. Beam layers are made by different materials that are continuously inhomogeneous along the length. General approach for deducing the strain energy release rate (SERR) is developed. The approach considers a beam made of adhesively bonded inhomogeneous layers with parallel delamination cracks. The approach uses the compliance of the beam. The external torques applied on the beam is smooth functions of time. The internal torques are determined by solving an internal statically undeterminate beam structure. Analysis of the SERR in a cantilever beam structure with two parallel delaminations is presented. The SERR found by the general approach is checked by a method that is based on the energy balance in the beam.
  1. R.S. Parihar, S.G. Setti, R.K. Sahu, “Recent advances in the manufacturing processes of functionally graded materials: a review“, Science and Engineering of Composite Materials, vol. 25, no. 2, pp. 309-336, 2018.
    https://doi.org/10.1515/secm-2015-0395
  2. A. Garg, W. Zheng, R. Raman, L. Li, “Machine Learning in Functionally Graded Materials and Nano FGMs: A Comprehensive Review of Predictive Modeling for Mechanical Behavior”, Arch Computat Methods Eng, 2025.
    https://doi.org/10.1007/s11831-025-10316-6
  3. H. Yao, B. Du, Z. Wang, W. Li, J. Dong, H. Liang, “Research Progress on Functionally Graded Materials for Epoxy Insulators in HV GIL/GIS”, Chinese Journal of Electrical Engineering, vol. 11, no. 2, pp. 150-164, 2025.
    https://doi.org/10.23919/CJEE.2025.000145
  4. I. Meyer, L. Glitt, T. Ehlers, “Adjustment through Functionally Gradedˮ, in Innovative Produktentwicklung durch additive Fertigung: Innovative Product Development by Additive Manufacturing, pp. 231-246, 2025.
    https://doi.org/10.1007/978-3-662-69327-8_15
  5. R. Jain, B. Sahoo, S. Jain, S. et al., “Functionally Graded Metallic Materials Via Additive Manufacturing: Research Progress on Processing, Challenges, and Applicationsˮ, Int. J. of Precis. Eng. and Manuf.-Green Tech., vol. 13, pp. 281-328, 2026.
    https://doi.org/10.1007/s40684-025-00766-5
  6. S.A. Hussain, M.S. Charoo, M.I. Ul Haq, “3D printing of functionally graded materials: Overcoming challenges and expanding applicationsˮ, in Multi-material Additive Manufacturing, pp. 67-97, 2025.
    https://doi.org/10.1016/B978-0-443-29228-6.00004- 9
  7. I. Dahan, U. Admon, J. Sarei, B. Yahav, M. Amar, N. Frage, M.P. Dariel, “Functionally graded Ti-TiC multilayers: the effect of a graded profile on adhesion to substrate”, Materials Science Forum, vol. 308-311, no. 2, pp. 923-929, 1999.
    https://doi.org/10.4028/www.scientific.net/MSF.30 8-311.923
  8. N. Dolgov, “Determination of Stresses in a Two-Layer Coating,” Strength of Materials, vol. 37, no. 2, pp. 422-431, 2005.
    http://doi.org/10.1007/s11223-005-0053-7
  9. Y. Tokovyy, C.-C. Ma, “Three-Dimensional Temperature and Thermal Stress Analysis of an Inhomogeneous Layer”, Journal of Thermal Stresses, vol. 36, no. 8, pp. 790 – 808, 2013.
    http://doi.org/10.1080/01495739.2013.787853
  10. Y. Tokovyy, C.-C. Ma, “Axisymmetric Stresses in an Elastic Radially Inhomogeneous Cylinder Under Length-Varying Loadings”, ASME Journal of Applied Mechanics, vol. 83, no. 11, 111007, 2016.
    http://doi.org/10.1115/1.4034459
  11. L. Tokova, A. Yasinskyy, C.-C. Ma, “Effect of the layer inhomogeneity on the distribution of stresses and displacements in an elastic multilayer cylinder”, Acta Mechanica, vol. 228, no. 8, pp. 2865-2877, 2017.
    http://doi.org/10.1007/s00707-015-1519-8
  12. V. Rizov, “Analysis of cylindrical delamination cracks in multilayered functionally graded non-linear elastic circular shafts under combined loads,ˮ Frattura ed Integrità Strutturale, vol. 46, pp. 158– 177, 2018.
    https://doi.org/10.3221/IGF-ESIS.46.16
  13. J- H. Yu, S. Guo, D.A. Gillard, “Bimaterial curvature measurements for CTE of adhesives: optimization, modelling, and stabilityˮ, J. Adhes. Sci. Technol., vol. 17, no. 2, pp. 149-164, 2003.
    https://doi.org/10.1163/156856103762301970
  14. J.S. Kim, K.W. Paik, S.H. Oh, “The Multilayer-Modified Stoney’s Formula for Laminated Polymer Composites on a Silicon Substrateˮ, J. Appl. Phys., vol. 86, pp. 5474–5479, 1999.
    https://doi.org/10.1063/1.371548
  15. S.-N. Nguyen, J. Lee, M. Cho, “Efficient higher-order zig-zag theory for viscoelastic laminated composite platesˮ, International Journal of Solids and Structures, vol. 62, no. 2, pp. 174-185, 2015.
    http://doi.org/10.1016/j.ijsolstr.2015.02.027
  16. S.-N. Nguyen, J. Lee, J.-W. Han, M. Cho, “A coupled hygrothermo-mechanical viscoelastic analysis of multilayered composite plates for long-term creep behaviorsˮ, Composite Structures, vol. 242, 112030, 2020.
    https://doi.org/10.1016/j.compstruct.2020.112030
  17. E.A. Levashov, D.V. Larikhin, D.V. Shtansky, A.S. Rogachev, H.E. Grigoryan, J.J. Moore, “Self-Propagating High-Temperature Synthesis of Functionally Graded PVD Targets with a Ceramic Working Layer of TiB2-TiN or Ti5Si3-TiN”, Journal of Materials Synthesis and Processing, vol. 10, pp. 319-330, 2002.
    https://doi.org/10.1023/A:1023881718671
  18. I. Markov, D. Dinev, “Theoretical and experimental investigation of a beam strengthened by bonded composite strip”, Reports of International Scientific Conference VSU’2005, pp. 123-131, 2005.
  19. N.E. Dowling, Mechanical behaviour of materials, Pearson, 2011.
  20. K. Bousmaha, S.A. Belalia, S.M. Chorfi, A. Tounsi, M.A. Al-Osta, A.E. Alluqmani, “On the dynamic behavior of plates made of porous advanced materials reinforced with carbon nanotubes using a p-version of finite element method,” Mechanics Based Design of Structures and Machines, pp. 1–30, 2025.
    https://doi.org/10.1080/15397734.2025.2534679
  21. A. Tounsi, Z. Belabed, F. Bounouara, M. Balubaid, S.R. Mahmoud, A.A. Bousahla, A. Tounsi, “A finite element approach for forced dynamical responses of porous FG nanocomposite beams resting on viscoelastic foundations,” Int. J. Struct. Stab. Dyn., 2650078, 2024.
    https://doi.org/10.1142/S0219455426500781
  22. S.M. Lee, “An Edge Crack Torsion Method for Mode III Delamination Fracture Testing”, J. Compos. Technol. Res., vol. 15, no. 3, pp. 193–201, 1993.
    https://doi.org/10.1520/CTR10369J
  23. J. Li, Y. Wang, “Analysis of a symmetric laminate with mid-plane free edge delamination under torsion: theory and application to the edge crack torsion (ECT) specimen for mode III toughness characterization”, Engineering Fracture Mechanics, vol. 94, no. 2, pp. 179-194, 1994.
    https://doi.org/10.1016/0013-7944(94)90002-7
  24. P.-E. Mazeran, M.-F. Arvieu, M. Bigerelle, S. Delalande, “Torsion delamination test, a new method to quantify the adhesion of coating: Application to car coatings”, Progress in Organic Coatings, vol. 110, pp. 134-139, 2027.
    https://doi.org/10.1016/j.porgcoat.2017.03.001
  25. R. Tasmim, H.V. Pour, “Torsion of reinforced glued laminated timber beam”, in 14th World Conference on Timber Engineering 2025 (WCTE 2025), 22-26 June 2025, Brisbane, Australia, pp. 3429 – 3435.
    https://doi.org/10.52202/080513-0420
  26. V. Rizov, “Theoretical analysis of delamination in a viscoelastic multilayered bar built-up at both ends”, RAD Conf. Proc., vol. 8, pp. 12-15, 2024.
    https://doi.org/10.21175/RadProc.2024.03
  27. V. Rizov, “Inhomogeneous beam structures of rectangular cross-section loaded in torsion: a delamination study with considering creep”, Procedia Structural Integrity, vol. 41, pp. 94–102, 2022.
    https://doi.org/10.1016/j.prostr.2022.05.012
  28. K.S. Chobanian, Stresses in combined elastic solids, Science, 1997.
  29. V.G. Zubchaninov, Fundamentals of theory of elasticity and plasticity, Vishaya Shkola, 1990.
  30. A. Mladensky, “Analysis of cracks in composite materials”, PhD Thesis, 2013.
Victor Rizov, "Analysis of multiple delamination in viscoelastic multilayered beams with rectangular section subjected to pure torsion", RAD Conf. Proc., vol. 9, 2025, pp. 13 -18; http://doi.org/10.21175/RadProc.2025.03
Other topic

LENGTHWISE FRACTURE ANALYSIS OF INHOMOGENEOUS FRAMES AT CREEP

Victor Rizov

DOI: 10.21175/RadProc.2025.04

Received: 4 AUG 2025, Reviews sent: 16 SEP 2025, Received revised: 6 OCT 2025, Accepted: 16 OCT 2025, Published online: 20 JAN 2026

| | | Full Text (PDF)

The present paper examines the lengthwise fracture of a continuously inhomogeneous portal frame by analyzing the time-dependent strain energy release rate (SERR). The frame is subjected to creep. The material of the frame has inhomogeneity in both thickness and width directions of the cross-section. The mechanical behavior of the material is treated by applying a non-linear stress-strain-time relationship. A solution to the SERR is derived assuming that the material properties involved in the non-linear stress-strain-time relationship vary continuously along the width and the thickness of the frame cross-section. The SERR is derived also by considering the complementary strain energy (CSE) for verification. The solution is applied to evaluate the variation of the SERR over the time. It is investigated how the material inhomogeneity along the width and the thickness of the frame affects the SERR.
  1. B.N. Kumar, H. Singh, H.S. Nanda, eds. Novel Applications of Functionally Graded Materials, CRC Press, 2025.
    https://doi.org/10.1201/9781003656333
  2. I. Meyer, L. Glitt, T. Ehlers, “Adjustment through Functionally Graded”, in Innovative Produktentwicklung durch additive Fertigung: Innovative Product Development by Additive Manufacturing 2023 (2025), pp. 231-246, 2025.
    https://doi.org/10.1007/978-3-662-69327-8_15
  3. R. Kumar, A. Agrawal, “Emerging Functionally Graded Materials for Bio-implant Applications—Design and Manufacturing”, in Additive Manufacturing of Bio-implants. Biomedical Materials for Multi-functional Applications, Springer, Singapore, 2024.
    https://doi.org/10.1007/978-981-99-6972-2_9
  4. R.F. Silva, P.G. Coelho, F.M. Conde, C.J. Almeida, A.L. Custódio, “Topology optimization of thermoelastic structures with single and functionally graded materials exploring energy and stress-based formulations”, Struct Multidisc Optim, vol. 68, 11, 2025.
    https://doi.org/10.1007/s00158-024-03929-1
  5. J. Toudehdehghan, W. Lim, K.E. Foo1, M.I.N. Ma’arof, J. Mathews, “A brief review of functionally graded materials”, MATEC Web of Conferences, vol. 131, 03010, 2017.
    https://doi.org/10.1051/matecconf/201713103010
  6. Y. Tokovyy, C.-C. Ma, “Axisymmetric Stresses in an Elastic Radially Inhomogeneous Cylinder Under Length-Varying Loadings”, J. Appl. Mech., vol. 83, no. 11, 111007, 2016.
    http://doi.org/10.1115/1.4034459
  7. K. Bousmaha, S.A. Belalia, S.M. Chorfi, A. Tounsi, M.A. Al-Osta, A.E. Alluqmani, “On the dynamic behavior of plates made of porous advanced materials reinforced with carbon nanotubes using a p-version of finite element method”, Mechanics Based Design of Structures and Machines, pp. 1–30, 2025.
    https://doi.org/10.1080/15397734.2025.2534679
  8. A. Tounsi, Z. Belabed, F. Bounouara, M. Balubaid, S.R. Mahmoud, A.A. Bousahla, A. Tounsi, “A finite element approach for forced dynamical responses of porous FG nanocomposite beams resting on viscoelastic foundations”, Int. J. Struct. Stab. Dyn., 2650078, 2024.
    https://doi.org/10.1142/S0219455426500781
  9. S.A. Meftah, S.M. Aldosari, A. Tounsi, T. Cuong-Le, K.M. Khedher, A.E. Alluqmani, “Simplified homogenization technique for nonlinear finite element analysis of in-plane loaded masonry walls”, Engineering Structures, vol. 306, 117822, 2024.
    https://doi.org/10.1016/j.engstruct.2024.117822
  10. N.E. Dowling, Mechanical behaviour of materials, Pearson, 2011.
  11. J. Chen, S. Tu, S. “Creep fracture parameters of functionally graded coating”, Journal of the Chinese Institute of Engineers, vol. 27, pp. 805–812, 2004.
    https://doi.org/10.1080/02533839.2004.9670931
  12. H. Guo, W. Tang, X. Tong, “Analysis of the Constraint-Based Creep Fracture Behavior of a Reactor Pressure Vessel with a Surface Crack Under Extreme High Temperature”, Nuclear Science and Engineering, pp. 1–11, 2025.
    https://doi.org/10.1080/00295639.2025.2503124
  13. S. Yu, W. Dong, F.M. Xu, M.B. Fu, Y. Tan, “Effects of heat treatment on the creep crack growth behavior in Al/Al-4wt% Cu functionally graded material”, Adv. Mater. Res., vol. 711, pp. 81-86, 2013.
    https://doi.org/10.4028/www.scientific.net/AMR.711. 81
  14. V. Rizov, “Non-linear fracture in bi-directional graded shafts in torsion”, Multidiscipline Modeling in Materials and Structures, vol. 15, pp. 156-169, 2018.
    https://doi.org/10.1108/MMMS-12-2017-0163
  15. V. Rizov, “Viscoelastic inhomogeneous beam under time-dependent strains: A longitudinal crack analysis”, Advances in computational design, vol. 6, no. 2, pp. 153-168, 2021.
    https://doi.org/10.12989/acd.2021.6.2.153153
  16. V. Rizov, “Analysis of Two Lengthwise Cracks in a Viscoelastic Inhomogeneous Beam Structure”, Engineering Transactions, vol. 68, pp. 397-415, 2020.
    https://doi.org/10.24423/EngTrans.1214.20201125
  17. D. Broek, Elementary engineering fracture mechanics, Springer, 1986.
Victor Rizov, "Lengthwise fracture analysis of inhomogeneous frames at creep", RAD Conf. Proc., vol. 9, 2025, pp. 19 - 25; http://doi.org/10.21175/RadProc.2025.04
Radiation Effects

THE EFFECT OF METALLIC MATERIALS ON THE FILTERING OF THE SPECTRUM OF MOBILE X-RAY GENERATORS WITH REGARD TO THE POSSIBLE INITIATION OF IMPROVISED EXPLOSIVE DEVICES

David Zoul, Marián Zelený, Pavlo Bakhmachuk, Jakub Haberhauer

DOI: 10.21175/RadProc.2025.05

Received: 29 SEP 2025, Reviews sent: 30 NOV 2025, Received revised: 6 JAN 2026, Accepted: 4 FEB 2026, Published online: 22 FEB 2026

| | | Full Text (PDF)

This work deals with the study of changes in the spectrum of X-ray radiation produced by mobile generators, when passing through various metallic filters. The main goal is to provide an overview of the effect of these materials on the radiation spectrum, which is crucial for applications in the field of IEDs (Improvised Explosive Devices) detection and other security measures. The results will be used serve as study material for students dealing with this issue addressing this topic. In the detection of suspicious objects or IEDs, X-ray systems play a key role. In practice, however, IEDs can also be found equipped with sensors that react to X-ray radiation, and single pulse is often enough to initiate an unwanted detonation of an explosive device. For this reason, filters made of various metals are used in portable X- ray systems, which reduce the probability of activation of the IEDs sensor. The filters are installed directly in front of the X-ray generator. The aim of our work was to determine the effect of filtration with various materials on the spectrum and to determine the extent of this effect on the function of IEDs switches. There is an urgent need to determine what number of photons for specific energies is safe for X-ray sensitive sensors that could be used in IEDs. It is therefore necessary to conduct a professional study that would allow to investigate the issue more thoroughly based on scientific data. Using High-Purity Germanium (HPGe) gamma spectrometer GC2018 (CANBERRA), we measured the X-ray spectra of continuous portable X-ray source ECO 200DS, transmitted through filters made of Al, Ti, Brass, Cu, Zr, Pb, and W of different thicknesses. The results show that heavier and thicker filters effectively reduce low-energy X-rays, thereby “hardening” the spectrum and lowering total radiation intensity. Lead and tungsten filters were found to be most effective in preventing the triggering of X-ray sensitive sensors commonly used in improvised explosive devices (IEDs), although at the cost of reduced image resolution. The best results with regard to the quality of the captured image were achieved by using a 2 mm thick Cu filter, or a 0.5 mm thick Pb filter at a source-detector distance of approximately 2 m. Below the mentioned filter thicknesses, some sensors were already triggered occasionally.
  1. J. Howell, “Filters for Portable X-rays: What do they actually do?”, Linkedin, 2020.
  2. Teledine ICM, “PIR Sensors in IEDs using constant potential generators”, Counter-IED Report, 2023.
    https://counteriedreport.com/wp-content/uploads/2023/05/63-67-Teledyne-ICM-article-Counter-IED-Report-Spring-Summer-2023.pdf
  3. International Bomb Disposal and Counter IED Professionals, “Passive Infrared Sensors (PIR) vs Fixed and Adjustable Kv portable X-Ray Generators”, Linkedin, 2021.
  4. D. Zoul, M. Zelený, “Vliv metalických materiálů na filtraci spektra brzdného záření pulzních generátorů s ohledem na možnou iniciaci nástražných výbušných systémů (The influence of metallic materials on the filtering of the bremsstrahlung spectrum of pulse generators with regard to the possible initiation of improvised explosive devices)”, Jaderná energie (Nuclear energy), 2/2024, pp. 30-37.
  5. Comet X-ray, Comet Portables and Mobile Catalog v 5. [Online]. Available: https://issuu.com/comet-xray/docs/comet_portables_and_mobile_catalog_v_5
  6. ELP GmbH, Golden Engineering XRS3 Gen 4. [Online]. Available: https://www.elp-gmbh.com/en/produkte/golden-engineering-xrs3-gen-4/
  7. X. Ma, M. Buschmamm, E. Unger, P. Homolka, “Classification of X-Ray Attenuation Properties of Additive Manufacturing and 3D Printing Materials Using Computed Tomography From 70 to 140 kVp”, Front. Bioeng. Biotechnol., vol. 9, 2021.
    https://doi.org/10.3389/fbioe.2021.763960
  8. NIST, X-Ray Mass Attenuation Coefficients. [Online]. Available: https://www.nist.gov/pml/x-ray-mass-attenuation-coefficients
  9. NIST, X-Ray Mass Attenuation Coefficients - Table 3. [Online]. Available: https://physics.nist.gov/PhysRefData/XrayMassCoef/tab3.html
  10. R. Taleei, M. Shahriari, “Monte Carlo simulation of X-ray spectra and evaluation of filter effect using MCNP4C and FLUKA code”, Appl. Radiat. Isot., vol. 67, no. 2, pp. 266-271, 2009.
    https://doi.org/10.1016/j.apradiso.2008.10.007
David Zoul, Marián Zelený, Pavlo Bakhmachuk, Jakub Haberhauer, "The effect of metallic materials on the filtering of the spectrum of mobile X-ray generators with regard to the possible initiation of improvised explosive devices", RAD Conf. Proc., vol. 9, 2025, pp. 26 - 30; http://doi.org/10.21175/RadProc.2025.05
Biochemistry

FREE FATTY ACIDS AND INFLAMMATION AS RISK FACTORS OF TYPE 2 DIABETES

Šaćira Mandal

DOI: 10.21175/RadProc.2025.06

Received: 29 OCT 2025, Reviews sent: 14 JAN 2026, Received revised: 4 FEB 2026, Accepted: 16 FEB 2026, Published online: 13 MAR 2026

| | | Full Text (PDF)

Type 2 diabetes (T2D) as a common type of diabetes mellitus is influenced by various factors such as genetics and environment. One of the most important risk factors for the development of T2D is insulin resistance (IR), the underlying mechanisms of which include impaired free fatty acid (FFA) metabolism and inflammation. Chronically elevated levels of plasma free fatty acids appear to disrupt normal glucose homeostasis, while increased levels of a key inflammatory marker, C-reactive protein (CRP), lead to endothelial dysfunction and other T2D complications. The aim of this study was to examine the relationship between plasma FFA concentration and CRP as an inflammatory marker in patients with diabetes. The research included 82 participants, 42 of whom were patients with type 2 diabetes and 40 healthy individuals as a control group, aged 40 to 65 years. Clinical and biochemical characteristics including body mass index (BMI), fasting glucose levels, HbA1c, insulin, CRP and lipid profile were determined using standard clinical methods, while the levels of individual FFAs were measured by gas chromatography. The results showed a positive correlation between myristic acid (C14:0) and CRP levels, as well as a negative association of docosapentaenoic acid (C22:5) with CRP levels (p<0.05) in control subjects. In the group of diabetics, a negative correlation of gamma-linolenic acid (C18:3) with CRP levels was observed (p<0.001). These findings suggest that concentrations of individual free fatty acids, with different chain lengths and degrees of saturation, such as C14:0 and C18:3, can be used as potential markers of low-grade inflammation and disease prognosis in T2D patients.
  1. International Diabetes Federation, Diabetes Atlas — 10th Edition, Diabetes Atlas, 2021.
  2. G.S. Hotamisligil, “Inflammation and metabolic disorders”, Nature, vol. 14, no. 7121, pp. 860–867, 2006.
    https://doi.org/10.1038/nature05485
  3. C. de Luca, J.M. Olefsky, “Inflammation and insulin resistance”, FEBS Letters, vol. 582, no. 1, pp. 97–105, 2008.
    https://doi.org/10.1016/j.febslet.2007.11.057
  4. M.C. Calle, M.L. Fernandez, “Inflammation and type 2 diabetes”, Diabetes Metab., vol. 38, no. 3, pp. 183–191, 2012.
    https://doi.org/10.1016/j.diabet.2011.11.006
  5. Š. Mandal, “Association of free fatty acid concentrations with glucose levels in Bosnian subjects”, RAD Conf. Proc, vol. 7, pp. 47–51, 2023.
    http://dx.doi.org/10.21175/RadProc.2023.09
  6. A. Pan, Y. Wang, J.M. Yuan, W.P. Koh, “High-sensitive C-reactive protein and risk of incident type 2 diabetes: a case-control study nested within the Singapore Chinese Health Study,” BMC Endocr Disord., vol. 17, no. 1, pp. 1–8, 2017.
    https://doi.org/10.1186/s12902-017-0159-5
  7. V.T. Samuel, G.I. Shulman, “The pathogenesis of insulin resistance: integrating signaling pathways and substrate flux”, J. Clin. Invest., vol. 126, no. 1, pp. 12–22, 2016.
    https://doi.org/10.1172/JCI77812
  8. A.I.S. Sobczak, C.A. Blindauer, A.J. Stewart, “Changes in plasma free fatty acids associated with type 2 diabetes”, Nutrients, vol. 11, no. 9, pp. 1–42, 2019.
    https://doi.org/10.3390/nu11092022
  9. C. Menni, et al., “Biomarkers for type 2 diabetes and impaired fasting glucose using an ontargeted metabolomics approach,” Diabetes, vol. 62, no. 12, pp. 4270–4276, 2013.
    https://doi.org/10.2337/db13-0570
  10. D. Tripathy, et al., “Elevation of free fatty acids induces inflammation and impairs vascular reactivity in healthy subjects”, Diabetes, vol. 52, no. 12, pp. 2882–2887, 2003.
    https://doi.org/10.2337/diabetes.52.12.2882
  11. J. Stanimirovic, et al., “Role of C-reactive protein in diabetic inflammation“, Mediators Inflamm., vol. 2022, 3706508, 2022.
    https://doi.org/10.1155/2022/3706508
  12. M.S. Barbalho, et al., “Association between hyperglycemia, C-reactive protein and other risk factors in patients at cardiovascular risk”, Journal of Diabetes Mellitus, vol. 6, no. 1, pp. 16–24, 2016.
    http://dx.doi.org/10.4236/jdm.2016.61003
  13. K. Eguchi, I. Manabe, “Islet inflammation in type 2 diabetes and physiology“, J Clin Invest., vol. 127, no. 1, pp. 14–23, 2017.
    https://doi.org/10.1172/jci88877
  14. C. Löwbeer, L. Mårtensson, E. Berg, H. Wallinder, “Associations between C-reactive protein and apolipoproteins, lipoprotein(a) and conventional serum lipids in outpatients: correlations and time trends”, Open Journal of Clinical Diagnostics, vol. 5, no. 2, pp. 33–40, 2015.
    http://dx.doi.org/10.4236/ojcd.2015.52006
  15. A.P. Simopoulos, “An increase in the omega-6/omega-3 fatty acid ratio increases the risk for obesity”, Nutrients, vol. 8, no. 3, pp. 1–17, 2016.
    https://doi.org/10.3390/nu8030128
  16. K. Eguchi, I. Manabe, “Macrophages and islet inflammation in type 2 diabetes,” Diabetes, Obesity and Metabolism, vol. 15 (Suppl 3), pp. 152–158, 2013.
    https://doi.org/10.1111/dom.12168
  17. M. Ebrahimi, et al., “Association of serum hs-CRP levels with the presence of obesity, diabetes mellitus, and other cardiovascular risk factors”, Journal of Clinical Laboratory Analysis, vol. 30, pp. 672-676, 2016.
    https://doi.org/10.1002/jcla.21920
  18. T.V. Velikova, P.P. Kabakchieva, Y.S. Assyov, T.А. Georgiev, “Targeting Inflammatory Cytokines to Improve Type 2 Diabetes Control,” Hindawi BioMed Res. Inter., vol. 2021, 7297419, 2021.
    https://doi.org/10.1155/2021/7297419
  19. D.R. Matthews, et al., “Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man”, Diabetologia, vol. 28, no. 7, pp. 412–19, 1985.
    https://doi.org/10.1007/bf00280883
  20. WHO, “Physical status: the use and interpretation of anthropometry. Report of a WHO Expert Committee”, World Health Organ Tech Rep Ser., no. 854, pp. 1–452, 1995.
  21. J. Folch, M. Lees, G.H.S. Stanley, “A simple method for the isolation and purification of total lipids from animal tissues”, J Biol Chem., vol. 226, no. 1, pp. 497–509, 1957.
    https://pubmed.ncbi.nlm.nih.gov/13428781
  22. G. Lepage, C.C. Roy, “Specific methylation of plasma nonesterified fatty acids in a one-step reaction”, J Lipid Res., vol. 29, no. 2, pp. 227–235, 1988.
    https://pubmed.ncbi.nlm.nih.gov/3367090
  23. L.I. Rachek, “Free fatty acids and skeletal muscle insulin resistance”, Prog Mol Biol Transl Sci., vol. 121, pp. 267–292, 2014.
    https://doi.org/10.1016/b978-0-12-800101-1.00008-9
  24. A.T. Kharroubi, H.M. Darwish, “Diabetes mellitus: The epidemic of the century”, World J Diabetes, vol. 6, no. 6, pp. 850-867, 2015.
    https://doi.org/10.4239/wjd.v6.i6.850
  25. Y.A. Nasykhova, et al., “Recent advances and perspectives in next generation sequencing application to the genetic research of type 2 diabetes”, World J Diabetes, vol. 10, no. 7, pp. 376–396, 2019.
    https://doi.org/10.4239/wjd.v10.i7.376
  26. D.E. King, A.G. Mainous, T.A. Buchanan, W.S. Pearson, “C-reactive protein and glycemic control in adults with diabetes”, Diabetes Care, vol. 26, no. 5, pp. 1535–9, 2003.
    https://doi.org/10.2337/diacare.26.5.1535
  27. C. Klein-Platat, J. Drai, M. Oujaa, J.-L. Schlienger, C. Simon, “Plasma fatty acid composition is associated with the metabolic syndrome and low-grade inflammation in overweight adolescents”, Am J Clin Nutr., vol. 82, no. 6, pp. 1178–84, 2005.
    https://doi.org/10.1093/ajcn/82.6.1178
  28. H. Petersson, et al., “Relationships between serum fatty acid composition and multiple markers of inflammation and endothelial function in an elderly population,” Atherosclerosis, vol. 203, no. 1, pp. 298–303, 2009.
    https://doi.org/10.1016/j.atherosclerosis.2008.06.020
  29. N. Rajkovic, et al., “Relationship between obesity, adipocytokines and inflammatory markers in type 2 diabetes: relevance for cardiovascular risk prevention”, Int. J. Environ. Res. Public Health, vol. 11, no. 4, pp. 4049–4065, 2014.
    https://doi.org/10.3390/ijerph110404049
  30. S. Santos, A. Oliveira, C. Lopes, “Systemic review saturated fatty acids on inflammation and circulating levels of adipokines”, Nutr. Res., vol. 33, no. 9, pp. 687–695, 2013.
    https://doi.org/10.1016/j.nutres.2013.07.002
  31. C. Nienaber-Rousseau, et al., “Interactions between C-reactive protein genotypes with markers of nutritional status in relation to inflammation”, Nutrients, vol. 6, no. 11, pp. 5034–5050, 2014.
    https://doi.org/10.3390/nu6115034
  32. M. Perreault, et al., “Plasma levels of 14:0, 16:0, 16:1 n-7, and 20:3 n-6 are positively associated, but 18:0 and 18:2 n-6 are inversely associated with markers of inflammation in young healthy adults”, Lipids, vol. 49, no. 3, pp. 255–263, 2014.
    https://doi.org/10.1007/s11745-013-3874-3
  33. D. Wu, et al., “Palmitic acid exerts proinflammatory effects on vascular smooth muscle cells by inducing the expression of C reactive protein, inducible nitric oxide synthase and tumor necrosis factor α”, International Journal of Molecular Medicine, vol. 34, no. 6, pp. 1706–1712, 2014.
    https://doi.org/10.3892/ijmm.2014.1942
  34. I.D. Santaren, et al., “Individual serum saturated fatty acids and markers of chronic subclinical inflammation: The Insulin Resistance Atherosclerosis Study (IRAS)”, J. Lipid Res., vol. 58, no. 11, pp. 2171–2179, 2017.
    https://doi.org/10.1194/jlr.p076836
  35. S.A. Khan, R.T. Jackson, “Polyunsaturated fatty acids, inflammation, and metabolic syndrome in South Asian Americans in Maryland”, Food Sci Nutr., vol. 6, no. 6, pp. 1575–1581, 2018.
    https://doi.org/10.1002/fsn3.698
  36. A.Z. Lalia, et al., “Effects of dietary n-3 fatty acids on hepatic and peripheral insulin sensitivity in insulin-resistant humans”, Diabetes Care, vol. 38, no. 7, pp. 1228–1237, 2015.
    https://doi.org/10.2337/dc14-3101
  37. C. Itsiopoulos, et al., “The role of omega-3 polyunsaturated fatty acid supplementation in the management of type 2 diabetes mellitus: A narrative review”, J. Nutr. Intermed. Metab., vol. 14, pp. 42–51, 2018.
    https://doi.org/10.1016/j.jnim.2018.02.002
  38. L. Kaska, et al., “The relationship between specific fatty acids of serum lipids and serum high sensitivity C- reactive protein levels in morbidly obese women”, Cell Physiol Biochem, vol. 34, no. 4, pp. 1101–1108, 2014.
    https://doi.org/10.1159/000366324
  39. E. Alvarez-Curto, G. Milligan, “Metabolism meets immunity: The role of free fatty acid receptors in the immune system”, Biochem. Pharmacol., vol. 114, pp. 3–13, 2016.
    https://doi.org/10.1016/j.bcp.2016.03.017
  40. A. Coope, A.S. Torsoni, L.A. Velloso, “Metabolic and inflammatory pathways on the pathogenesis of type 2 diabetes”, Eur. J. Endocrinol., vol. 174, no. 5, pp. R175–R187, 2016.
    https://doi.org/10.1530/eje-15-1065
  41. Š. Mandal, A. Čaušević, “The correlation between C-reactive protein and regulation of glycemia in type-2 diabetic patients”, Bull. Chem. Technol. Bosnia Herzegovina, vol. 48, pp. 5–8, 2017.
    https://hemija.pmf.unsa.ba/glasnik/index.php/2014-03-20-22-03-11/issue-48
  42. K.M. Dinh, et al., “Low-grade inflammation is negatively associated with physical health-related quality of life in healthy individuals: results from The Danish Blood Donor Study (DBDS)”, PLoS One., vol. 14, no. 5, pp. e0216339, 2019.
    https://doi.org/10.1371/journal.pone.0214468
  43. S. Kanmani, et al., “Association of C-reactive protein with risk of developing type 2 diabetes mellitus, and role of obesity and hypertension: a large population-based Korean cohort study”, Sci Rep., vol. 9, 4573, 2019.
    https://doi.org/10.1038/s41598-019-40987-8
  44. Š. Mandal, “Association of marker of inflammation, hepatic enzymes and lipid profile in Type 2 diabetes”, RAD Conf. Proc, vol. 6, pp. 119–123, 2022.
    http://doi.org/10.21175/RadProc.2022.21
  45. Š. Mandal, A. Causevic, H. Dzudzevic-Cancar, S. Semiz, “Free fatty acid profile in type 2 diabetic subjects with different control of glycemia,” in CMBEBIH 2017, Springer, 2017, pp. 781–786.
    https://doi.org/10.1007/978-981-10-4166-2_119
  46. M. Poreba, et al., “Relationship between polyunsaturated fatty acid composition in serum phospholipids, systemic low-grade inflammation, and glycemic control in patients with type 2 diabetes and atherosclerotic cardiovascular disease,” Cardiovasc Diabetol., vol. 17, no. 1, 29, 2018.
    https://doi.org/10.1186/s12933-018-0672-5
Šaćira Mandal, "Free fatty acids and inflammation as risk factors of type 2 diabetes", RAD Conf. Proc., vol. 9, 2025, pp. 31 - 36; http://doi.org/10.21175/RadProc.2025.06
Health and Environment

CHROMIUM CONTENT IN THE DRINKING WATER OF PLEVEN REGION – SOURCES AND HEALTH CONTROL

Emilia Bankova, Vanya Birdanova, Tsvetelina Vitkova, Dima Tsanova, Suzana Nikolova, Ivan Traykov

DOI: 10.21175/RadProc.2025.07

Received: 30 OCT 2025, Reviews sent: 25 JAN 2026, Received revised: 3 FEB 2026, Accepted: 18 FEB 2026, Published online: 13 MAR 2026

| | | Full Text (PDF)

Ensuring access to high-quality drinking water in Bulgaria presents significant challenges due to an aging and deteriorating water distribution network, anthropogenic pollution of water sources, and the natural migration of chemical elements from geological substrates into groundwater. These factors contribute to the contamination of water resources with harmful substances such as heavy metals, pesticides, and fertilizers, posing serious risks to human health. Particular concern arises from chromium contamination, especially in regions with naturally elevated chromium levels. Hexavalent chromium (Cr6+) is toxic and carcinogenic, whereas trivalent chromium (Cr3+) is an essential trace element. This study analyses data on chromium concentrations in drinking water across the Pleven region over an eight- year period, based on monitoring conducted by the Regional Health Inspectorate – Pleven. Results show that approximately 26% of the 1,242 samples collected exceeded the maximum allowable chromium concentration of 50 μg/L, with the highest recorded value reaching 138.82 μg/L. According to both national and European legislation, the established limit applies to total chromium, without differentiating between its hexavalent and trivalent forms. These findings highlight the urgent need for increased monitoring and implementation of modern water treatment technologies to reduce chromium levels and ensure safe drinking water in the affected areas, with the primary goal of protecting public health and promoting sustainable management of Bulgaria's water resources.
  1. K.R. Vasilev, P. Gatseva, Hygiene of Waters. Textbook on Hygiene for Dental Medicine Students and Other Medical Specialties, edited by Prof. Dr. Tanya Tarnovska, MD, DSc. Lax Book, Plovdiv, 2021. ISBN 978-619-189-160-3.
  2. K. Petrov, “Geo-economic Significance of the Water Sector for the Regional Development of Bulgaria”, Business Directions, vol. 1, pp. 14–39, 2020 (in Bulgarian).
    https://bjournal-bfu.bg/uploads/posts/2020_1_14_39_bg.pdf
  3. R. Gyurov, Kh. Kharizanov, “Geopathogenic Zones in Bulgaria and Quality of Life”, Yearbook of the Department of Natural Sciences 2014, NBU, pp. 66-78, 2015.
  4. D. Dermatas, C. Vatserisb, I. Panagiotakis, M. Chrysochoou, “Potential Contribution of Geogenic Chromium in Groundwater Contamination of a Greek Heavily Industrialized Area”, Chem. Eng. Trans., vol. 28, pp. 217–222, 2012.
    https://doi.org/10.3303/CET1228037
  5. P. Kalinkov, I. Angelova, “Solving the Problem of Hexavalent Chromium Presence in Groundwater Used for Drinking and Domestic Purposes in Several Settlements in Bulgaria”, BULAKVA Journal, vol. 3, pp. 75–79, 2016 (in Bulgarian).
    https://drive.google.com/file/d/0B-LENp4qQ5lbM21hXzBSanNNdmM/edit?resourcekey=0-0kAo2dWthyn510UjBJ6Ceg
  6. I. Angelova, I. Ivanov, S. Lazarova, T. Venelinov, “Use of combined approach for the determination of hexavalent chromium origin in the ground water”, Annual of the University of Architecture, Civil Engineering and Geodesy (UACEG), vol. 51, no. 6, pp. 45–60, 2018.
  7. National Statistical Institute (NSI), “Population by Statistical Regions, Districts, Municipalities, Settlements, Sex and Age”. [Online]. Available: https://infostat.nsi.bg/infostat/pages/reports/query.jsf?x_2=1962 [Accessed: Feb. 15, 2024].
  8. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy, Official Journal of the European Communities, L 327, pp. 1–73, 2000.
    http://data.europa.eu/eli/dir/2000/60/oj
  9. Water Act of the Republic of Bulgaria, State Gazette No. 67/27.07.1999 (final amendment Gazette No. 104/5.12.2025).
    https://lex.bg/laws/ldoc/2134673412
  10. Kh. Antonov, D. Danchev, Groundwaters in the People’s Republic of Bulgaria, State Publishing House 'Technica', Sofia, 1980.
  11. Basin Directorate “Danube Region”, “Interim Review of Identified Significant Water Management Problems in the Danube River Basin District”, 2014.
    https://www.bd-dunav.bg/content/upravlenie-na-vodite/plan-za-upravlenie-na-rechniia-baseyn/purb-2010-2015-v-dunavski-rayon-/
  12. E. Bankova, K. Vasilev, D. Zlatanova et al., “GIS Prognosis for Nitrate Pollution of Shallow Groundwater Sources“, Ecologia Balkanica, vol. 16, no. 2, pp. 137–148, 2024.
    https://eb.bio.uni-plovdiv.bg/wp-content/uploads/2024/12/eb20242137.pdf
  13. Regulation No. 9 of 16 March 2001 on the Quality of Water Intended for Drinking and Domestic Purposes, State Gazette No. 30, Sofia, Bulgaria, 2001.
    https://lex.bg/laws/ldoc/-549175806
  14. Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption, Official Journal of the European Communities, L 330, pp. 32–54, 1998.
    http://data.europa.eu/eli/dir/1998/83/oj
  15. E. Bankova, K. Vasilev, V. Birdanova et al., “Assessment of Groundwater Sources for Small Settlements in Pleven District for Ensuring Standard Drinking Water with Respect to Nitrate Content”, in Proc. 6th Natl. Conf. Bulgarian Society for Hygiene and Public Health, Medical University – Pleven, 2023, pp. 463–471.
  16. G. Genchi, G. Lauria, A. Catalano, A. Carocci, M.S. Sinicropi, “The Double Face of Metals: The Intriguing Case of Chromium”, Applied Sciences, vol. 11, no. 2, 638, 2021.
    https://doi.org/10.3390/app11020638
  17. W.L. Guo et al., “Hypoglycemic and Hypolipidemic Mechanism of Organic Chromium Derived from Chelation of Grifola frondosa Polysaccharide-Chromium (III) and Its Modulation of Intestinal Microflora in High-Fat Diet and STZ-Induced Diabetic Mice”, Int. J. Biol. Macromol., vol. 145, pp. 1208–1218, 2020.
    https://doi.org/10.1016/j.ijbiomac.2019.09.206
  18. V. John, “New evidence against Chromium as an essential trace element”, J. Nutr., vol. 147, no. 12, pp. 2212-2219, 2017.
    https://doi.org/10.3945/jn.117.255901
  19. D.M. Hausladen, S. Fendorf, “Hexavalent Chromium Generation within Naturally Structured Soils and Sediments”, Environ. Sci. Technol., vol. 51, no. 4, pp. 2058–2067, 2017.
    https://doi.org/10.1021/acs.est.6b04039
  20. R. Saha, R. Nandi, B. Saha, “Sources and toxicity of hexavalent chromium”, J. Coord. Chem., vol. 64, no. 10, pp. 1782–1806, 2011.
    https://doi.org/10.1080/00958972.2011.583646
  21. M.N. Sepehr et al., “Removal of Cr(III) from tanning effluent by Aspergillus niger in an airlift bioreactor”, Sep. Purif. Technol., vol. 96, pp. 256–262, 2012.
    https://doi.org/10.1016/j.seppur.2012.06.013
  22. H. Sun, J. Brocato, M. Costa, “Oral Chromium Exposure and Toxicity”, Curr. Environ. Health Rep., vol. 2, pp. 295–303, 2015.
    https://doi.org/10.1007/s40572-015-0054-z
  23. G. Hu, P. Zheng, H. Feng, G. Jia, “Imbalance of Oxidative and Reductive Species Involved in Chromium(VI)-Induced Toxic Effects”, React. Oxyg. Species, vol. 3, pp. 1–11, 2017.
    https://doi.org/10.20455/ros.2017.803
  24. United States Environmental Protection Agency (US EPA). “Chromium in Drinking Water”. [Online]. Available: https://www.epa.gov/sdwa/chromium-drinking-water [Accessed: Feb. 27, 2024].
  25. P. Rizza et al., “3-(Dipropylamino)-5-hydroxybenzofuro[2,3-f]quinazolin-1(2H)-one (DPA-HBFQ-1) Plays an Inhibitory Role on Breast Cancer Cell Growth and Progression”, Eur. J. Med. Chem., vol. 107, pp. 275–287, 2016.
    https://doi.org/10.1016/j.ejmech.2015.11.004
  26. Regulation No. 1 of 10 October 2007 on the Exploration, Use, and Protection of Groundwater, State Gazette No. 87 (amended No. 102/23.12.2016).
    https://lex.bg/laws/ldoc/2135569070/
  27. B. Saha, C. Orvig, “Biosorbents for hexavalent chromium elimination from industrial and municipal effluents”, Coord. Chem. Rev., vol. 254, no. 23-24, pp. 2959-2972, 2010.
    https://doi.org/10.1016/j.ccr.2010.06.005
  28. M.H. Mondal et al., “A comprehensive review on chromium chemistry along with detection, speciation, extraction and remediation of hexavalent chromium in contemporary science and technology”, Vietnam J. Chem., vol. 59, no. 6, pp. 711- 732, 2021.
    https://doi.org/10.1002/vjch.202100048
Emilia Bankova, Vanya Birdanova, Tsvetelina Vitkova, Dima Tsanova, Suzana Nikolova, Ivan Traykov, "Chromium content in the drinking water of Pleven region – sources and health control", RAD Conf. Proc., vol. 9, 2025, pp. 37 - 42; http://doi.org/10.21175/RadProc.2025.07
Medical Science

NUTRITION AND ACNE: EXPLORING THE CONNECTION

Vanya Birdanova, Preslav Vasilev, Ivelina Ruseva, Ivelina Yordanova, Iveta Petrova, Valentina Kozova

DOI: 10.21175/RadProc.2025.08

Received: 30 OCT 2025, Accepted: 13 MARCH 2026, Published online: 02 APR 2026

| | | Full Text (PDF)

Acne vulgaris is a persistent inflammatory skin condition affecting the pilosebaceous unit. Its development involves a combination of factors, including increased sebum production, altered keratinization, microbial colonization by Cutibacterium acnes, and inflammation. Additional contributors include hormonal changes, genetic predisposition, stress, and dietary habits. Foods with a high glycemic index, dairy products, and energy-dense meals may influence acne severity, particularly in Western-type diets. This study examined the relationship between acne severity and dietary habits among 46 Bulgarian women aged 14–40 years. Acne severity was graded using the Global Acne Grading System (GAGS), and diet was assessed through a Food Frequency Questionnaire (FFQ). Lower daily consumption of antioxidant- and fiber-rich foods (fruits, vegetables, whole grains, and legumes) was observed. Acne severity showed a significant negative correlation with nut intake (r = –0.51; p < 0.05) and positive correlations with milk (r = 0.46; p < 0.043), sugary foods and honey (r = 0.61; p < 0.016). Frequent consumption of sunflower oil, processed meats, and beer was more common among participants with severe acne. These findings suggest that energy-dense foods rich in fats and sugars, as well as milk and alcohol, may exacerbate acne development in young women.
  1. A.M. Layton, D. Thiboutot, J. Tan, “Reviewing the global burden of acne: how could we improve care to reduce the burden?”, Br. J. Dermatol., vol. 184, no. 2, pp. 219–225, 2021.
    https://doi.org/10.1111/bjd.19477
  2. D.D. Lynn, T. Umari, C.A. Dunnick, R.P. Dellavalle, “The epidemiology of acne vulgaris in late adolescence”, Adolesc. Health Med. Ther., vol. 7, pp. 13–25, 2016.
    https://doi.org/10.2147/AHMT.S55832
  3. E.A. Tanghetti, et al., “Understanding the burden of adult female acne”, J. Clin. Aesthet. Dermatol., vol. 7, no. 2, pp. 22–30, 2014.
    https://jcadonline.com/understanding-the-burden-of-adult-female-acne/
  4. B. Dréno, V. Bettoli, E. Araviiskaia, M. Sanchez Viera, A. Bouloc, “The influence of exposome on acne”, J. Eur. Acad. Dermatol. Venereol., vol. 32, no. 5, pp. 812–819, 2018.
    https://doi.org/10.1111/jdv.14820
  5. L. Penso, et al., “Association between adult acne and dietary behaviors: findings from the NutriNet-Santé prospective cohort study”, JAMA Dermatol., vol. 156, no. 8, pp. 854–862, 2020.
    https://doi.org/10.1001/jamadermatol.2020.1602
  6. J.S. Barbieri, “Diet and acne – challenges of translating nutritional epidemiologic research into clinical practice”, JAMA Dermatol., vol. 156, no. 8, pp. 841–843, 2020.
    https://doi.org/10.1001/jamadermatol.2020.1601
  7. J.Y. Jung, et al., “Effect of dietary supplementation with omega-3 fatty acid and gamma-linolenic acid on acne vulgaris: a randomized, double-blind, controlled trial,” Acta Derm. Venereol., vol. 94, no. 5, pp. 521–525, 2014.
    https://doi.org/10.2340/00015555-1802
  8. J. Meixiong, C. Ricco, C. Vasavda, B.K. Ho, “Diet and acne: a systematic review”, JAAD Int., vol. 7, pp. 95–112, 2022.
    https://doi.org/10.1016/j.jdin.2022.02.012
  9. A. Doshi, A. Zaheer, M.J. Stiller, “A comparison of current acne grading systems and proposal of a novel system”, Int. J. Dermatol., vol. 36, no. 6, pp. 416–418, 1997.
    https://doi.org/10.1046/j.1365-4362.1997.00099.x
  10. Ministry of Health of the Republic of Bulgaria and NCPHA, Healthy Eating Guidelines for Students Aged 7–19 Years in Bulgaria, Sofia, 2020.
    https://ncpha.government.bg/uploads/pages/3001/NPPNCD_2014-2020_Healthy_eating-students-7-19.pdf
  11. Ministry of Health of the Republic of Bulgaria and NCPHA, Healthy Eating Guidelines for the Population Aged 18 Years and Over in the Republic of Bulgaria, Sofia, 2020.
    https://ncpha.government.bg/uploads/pages/3001/NPPNCD_2014-2020_Healthy_eating.pdf
  12. K. Bhate, H.C. Williams, “Epidemiology of acne vulgaris”, Br. J. Dermatol., vol. 168, no. 3, pp. 474–485, 2013.
    https://doi.org/10.1111/bjd.12299
  13. F.W. Danby, “Nutrition and acne”, Clin. Dermatol., vol. 28, no. 6, pp. 598–604, 2010.
    https://doi.org/10.1016/j.clindermatol.2010.03.020
  14. B.C. Melnik, “Linking diet to acne metabolomics, inflammation, and comedogenesis: an update”, Clin. Cosmet. Investig. Dermatol., vol. 8, pp. 371–388, 2015.
    https://doi.org/10.2147/CCID.S69135
  15. R.N. Smith, et al., “The effect of a high-protein, low glycemic-load diet on acne vulgaris and the hormonal markers of acne”, J. Am. Acad. Dermatol., vol. 57, no. 2, pp. 247–256, 2007.
    https://doi.org/10.1016/j.jaad.2007.01.046
  16. N.H. Ismail, Z.A. Manaf, N.Z. Azizan, “High glycemic load diet, milk and ice cream consumption are related to acne vulgaris in Malaysian young adults: a case control study”, BMC Dermatol., vol. 12, p. 13, 2012.
    https://doi.org/10.1186/1471-5945-12-13
  17. H.H. Kwon, et al., “Clinical and histological effect of a low glycemic load diet in treatment of acne vulgaris in Korean patients: a randomized, controlled trial”, Acta Derm. Venereol., vol. 92, no. 4, pp. 341–346, 2012.
    https://doi.org/10.2340/00015555-1262
  18. T.S.S. Suppiah, et al., “Acne vulgaris and its association with dietary intake: a Malaysian perspective”, Asia Pac. J. Clin. Nutr., vol. 27, no. 5, pp. 1141–1145, 2018.
    https://doi.org/10.6133/apjcn.072018.01
  19. A. Guertler, et al., “Exploring the potential of omega-3 fatty acids in acne patients: a prospective intervention study,” J. Cosmet. Dermatol., vol. 23, no. 10, pp. 3295–3304, 2024.
    https://doi.org/10.1111/jocd.16434
  20. I. Ryguła, W. Pikiewicz, K. Kaminiów, “Impact of diet and nutrition in patients with acne vulgaris”, Nutrients, vol. 16, p. 1476, 2024.
    https://doi.org/10.3390/nu16101476
  21. B. Dreno, et al., “Female type of adult acne: physiological and psychological considerations and management”, J. Dtsch. Dermatol. Ges., vol. 16, no. 10, pp. 1185–1194, 2018.
    https://doi.org/10.1111/ddg.13664
Vanya Birdanova, Preslav Vasilev, Ivelina Ruseva, Ivelina Yordanova, Iveta Petrova, Valentina Kozova, "Nutrition and acne: exploring the connection", RAD Conf. Proc., vol. 9, 2025, pp. 43 - 46; http://doi.org/10.21175/RadProc.2025.08