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Gdańsk University of Technology

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Publications from the year 2025

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  • Text analytics for co-creation in public sector organizations: a literature review-based research framework
    • Nina Rizun
    • Aleksandra Revina
    • Noella Edelmann
    2025 Full text ARTIFICIAL INTELLIGENCE REVIEW

    The public sector faces considerable challenges that stem from increasing external and internal demands, the need for diverse and complex services, and citizens’ lack of satisfaction and trust in public sector organisations (PSOs). An alternative to traditional public service delivery is the co-creation of public services. Data analytics has been fueled by the availability of immense amounts of data, including textual data, and techniques to analyze data, so it has immense potential to foster data-driven solutions for the public sector. In the paper, we systematically review the existing literature on the application of Text Analytics (TA) techniques on textual data that can support public service co-creation. In this review, we identify the TA techniques, the public services and the co-creation phase they support, as well as envisioned public values for the stakeholder groups. On the basis of the analysis, we develop a Research Framework that helps to structure the TA-enabled co-creation process in PSOs, increases awareness among public sector organizations and stakeholders on the significant potential of TA in creating value, and provides scholars with some avenues for further research.

  • The Adsorption of Ru-Based Dyes on the TiO2 Surface to Enhance the Photovoltaic Efficiency of Dye-Sensitized Solar Cell Devices
    • Małgorzata Makowska-janusik
    • Katarzyna Filipecka-Szymczyk
    • Daniel Pelczarski
    • Waldemar Stampor
    • Maciej Zalas
    2025 MOLECULES

    Adsorption of mononuclear tris(bipyridine) ruthenium(II) complexes and binuclear tris(bipyridine) ruthenium(II) complexes equipped with carboxyl groups (-COOH) on the (111) surface of TiO2 crystal in anatase form was modeled using Monte Carlo simulations, applying the Universal force field. It was shown that the adsorption efficiency of the ruthenium-based dyes on the TiO2 surface depends on the position of the anchoring -COOH group in the molecular structure. The increase in the number of possible anchor groups in the dyes increases their ability to deposit on the surface of semiconductors. The chemisorbed molecules, such as mononuclear tris(bipyridine) ruthenium(II) complexes with the -COOH group in para position (RuLp) and binuclear tris(bipyridine) ruthenium(II) complexes called B3 with two anchoring -COOH groups and phenyl in the spacer, interact with the adsorber and other neighboring dyes, changing their electron and optical properties. The obtained computational results help to explain the behavior of the dyes on the TiO2 surface, giving impact on their DSSC applications.

  • The effect of hydrothermal carbonization (HTC) on entrained flow steam gasification of sewage sludge. Experimental validation of various gasification models
    • Jakub Mularski
    • Kamil Stasiak
    • Michał Ostrycharczyk
    • Michał Czerep
    • Mateusz Wnukowski
    • Krystian Krochmalny
    • Marcin Baranowski
    • Paweł Ziółkowski
    • Mateusz Kowal
    • Amit Arora
    • Mgr Inż Vishwajeet
    • Halina Pawlak-kruczek
    • Lukasz Niedzwiecki
    • Dariusz Mikielewicz
    2025 ENERGY

    Proper sewage sludge management is challenging due to legal requirements, environmental concerns, and logistical complexities. Steam gasification offers a promising solution by producing high-quality syngas. While research has largely focused on fixed bed gasifiers, their scalability limitations restrict their economic viability. Entrained flow gasifiers, scalable to hundreds of megawatts as demonstrated in coal gasification, present a practical alternative for large-scale bioenergy with carbon capture and storage (BECCS) applications. However, designing such systems requires precise modeling approaches. This study experimentally validates equilibrium models and a computational fluid dynamics (CFD) approach for steam gasification of raw sewage sludge and hydrothermally carbonized (HTC) sludge. HTC pretreatment improved syngas quality by facilitating the use of CO2 as a feedstock carrier for entrained flow gasifiers. Among the models tested, the CFD approach and a tuned semi-equilibrium model closely matched experimental data, with average absolute errors of 4.5 % and 2.9 % in mole fraction, respectively. Using a 3-m drop tube furnace, entrained flow steam gasification demonstrated the production of high-quality syngas and offering practical scalability. This scalability enables the development of efficient BECCS power plants with negative CO2 emissions, showcasing the potential of entrained flow gasifiers for sustainable energy and environmental management.

  • The Impact of 8- and 4-Bit Quantization on the Accuracy and Silicon Area Footprint of Tiny Neural Networks
    • Paweł Tumialis
    • Marcel Skierkowski
    • Jakub Przychodny
    • Paweł Obszarski
    2025 Electronics

    In the field of embedded and edge devices, efforts have been made to make deep neural network models smaller due to the limited size of the available memory and the low computational efficiency. Typical model footprints are under 100 KB. However, for some applications, models of this size are too large. In low-voltage sensors, signals must be processed, classified or predicted with an order of magnitude smaller memory. Model downsizing can be performed by limiting the number of model parameters or quantizing their weights. These types of operations have a negative impact on the accuracy of the deep network. This study tested the effect of model downscaling techniques on accuracy. The main idea was to reduce neural network models to 3 k parameters or less. Tests were conducted on three different neural network architectures in the context of three separate research problems, modeling real tasks for small networks. The impact of the reduction in the accuracy of the network depends mainly on its initial size. For a network reduced from 40 k parameters, a decrease in accuracy of 16 percentage points was achieved, and for a network with 20 k parameters, a decrease of 8 points was achieved. To obtain the best results, knowledge distillation and quantization-aware training methods were used for training. Thanks to this, the accuracy of the 4-bit networks did not differ significantly from the 8-bit ones and their results were approximately four percentage points worse than those of the full precision networks. For the fully connected network, synthesis to ASIC (application-specific integrated circuit) was also performed to demonstrate the reduction in the silicon area occupied by the model. The 4-bit quantization limits the silicon area footprint by 90%.

  • The impact of China’s One-Belt One-Road initiative on international trade and global value chains
    • Yuxin Lu
    • Joanna Wolszczak-Derlacz
    2025 Asia-Pacific Journal of Accounting & Economics

    This study examines the potential effects of China’s ‘One-Belt One-Road’initiative (OBOR) on trade flows and global value chain (GVC) connections.The empirical analysis is based on the augmented trade gravity model, which comprises 186 economies and 199 of their partners from 2000 to 2018. We also estimate the gravity model for involvement in GVC (domestic value added in intermediate exports, foreign value added in exports, and one country’s contributed value in another’s total exports). OBOR proves to be positively correlated with international trade and GVC, while some corridors seem to benefit more than others (e.g. China-Pakistan,China-Mongolia-Russian Federation, and Bangladesh-China-India-Myanmar).

  • The impact of goat hair as a natural animal fiber on properties of the lightweight cement composite
    • Najmeh Hassas
    • Farzam Omidi Moaf
    • Marzena Kurpińska
    • Teresa Bardzińska-Bonenberg
    • Justyna Borucka
    • Hakim S. Abdelgader
    • Rohan Soman
    • Mikołaj Miśkiewicz
    2025 Scientific Reports

    The increasing demand for sustainable and eco-friendly construction materials has prompted the exploration of natural fibers as reinforcement in cement composites. This study investigates the potential of goat hair as a natural fiber reinforcement in lightweight cement composites to enhance mechanical properties and sustainability. The research evaluates goat-hair-reinforced composites’ flexural and compressive strengths at 7 and 28 days after mixing. The results show that the inclusion of goat hair at a rate of 0.4% of cement, as a reinforcing material, leads to a significant increase in flexural and compressive strength. Specifically, flexural strength increased by 2.5% and 21.8%, while compressive strength improved by 5.5% and 21.5% at water-to-cement ratios of 0.4 and 0.5, respectively, compared to the control mixture. The findings demonstrate the effectiveness of goat hair in improving mechanical performance while reducing the environmental footprint of construction materials. This study highlights the need for further exploration of natural fibers in sustainable construction practices, focusing on optimizing mechanical performance and eco-friendly materials for broader applications.

  • The Impact of Hybrid Flame Retardant Compositions on the Performance of Foamed Flexible Polyurethane/Ground Tire Rubber Composites
    • Paulina Kosmela
    • Adam Olszewski
    • Mateusz Barczewski
    • Adam Piasecki
    • Aleksander Hejna
    2025 JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE

    Current sustainability-oriented trends affect polyurethane (PU) materials and stimulate the incorporation of recycled or waste-based materials as fillers. Ground tire rubber (GTR) poses as an auspicious candidate due to the excellent performance of car tires. Despite the benefits related to the mechanical performance, it contributes to the increasing flammability of the resulting composites. Herein, presented work assessed the impact of hybrid flame retardant (FR) combinations of ammonium polyphosphate (APP) or melamine cyanurate (MC) with organophosphorus compounds on the performance of foamed flexible PU/GTR composites. Such works are of vital importance, because matching to the needs of material with the mode of action of particular FRs is quite challenging. Except for the flammability reduction, they also affect structure and performance of composites. Fire resistance was enhanced for all applied FRs compositions; however, APP was found more effective than MC due to the efficient formation of protective char layer. Moreover, introduction of MC induced heterogeneity of cellular structure and excessive stiffening of PU structure, which increased its friability and cells’ coalescence, deteriorating thermal insulation performance and damping ability.

  • The impact of mGlu2 or mGlu5 receptor activators on the production of l-arginine derivatives and the expression of PRMT5 or DDAH1 enzymes in animal models of cognitive decline
    • Agata Płoska
    • Adrianna Radulska
    • Anna Siekierzycka
    • Paulina Cieślik
    • Michał Santocki
    • Iwona T. Dobrucki
    • Leszek Kalinowski
    • Joanna M. Wierońska
    2025 NITRIC OXIDE-BIOLOGY AND CHEMISTRY

    L-arginine derivatives (ADMA, SDMA, NMMA) are endogenous inhibitors of nitric oxide (NO֗) production, which is essential in critical brain processes including blood-brain barrier (BBB) integrity and long-term potentiation (LTP). ADMA and NMMA are degraded by dimethylarginine dimethylaminohydrolase 1 (DDAH1) and protein arginine methyltransferase 5 (PRMT5) is an emerging epigenetic enzyme that mainly represses transcription of target genes via symmetric dimethylation of arginine residues. There is no data concerning the impact of metabotropic glutamate receptors (mGlu) ligands on this aspect of brain physiology. In the present studies the impact of positive allosteric modulators (PAM) of mGlu5 (CDPPB) and mGlu2 (LY487379) receptors on L-arginine derivatives, DDAH1 and PRMT5 expression in mouse models of cognitive dysfunction induced with MK-801(0.3 mg/kg) or scopolamine (1 mg/kg), was investigated. Experiments were performed both after acute and chronic (14 days) administration of the compounds, which were administered at the doses 0.1–5 mg/kg (CDBBB) and 0.1–1 mg/kg (LY487379). The chronic administration of both compounds normalized the level of L-arginine derivatives in MK-801 model (in brain and plasma) and only low dose of CDPPB prevented scopolamine-induced changes. The expression of DDAH1 and PRMT5 was modulated by CDPPB and LY487379, both in MK-801 and scopolamine models. In the novel object recognition (NOR) test low doses of the compounds, inactive after single administration, prevented cognitive decline after chronic injections. Our findings highlight the potential of mGlu receptor modulators in treating schizophrenia and possibly de-mentia by normalizing L-arginine derivatives production, preventing from nitric oxide synthases uncoupling.

  • The influence of brace to chord rotational connection stiffness on stability of the truss
    • Marcin Krajewski
    2025 Bulletin of the Polish Academy of Sciences-Technical Sciences

    The paper is devoted to the numerical analysis of the roof truss subjected to upward wind loading and braced at the tensioned top chord. The linear buckling analysis were performed for the beam and shell model of the structure. As the result the influence of rotational connection stiffness between the brace and the top chord on the truss stability was appointed. The biaxial strength testing machine was used to conduct the experimental tests of the rotational connection stiffness between selected steel profiles. The results in the form of measured structural displacements and rotations were presented. The static nonlinear analysis results performed for the shell model of the structural connection were compared to the results obtained on the experimental set-up.

  • The influence of chitosan's molecular weight, concentration, and dissolution method on the properties of electrophoretically deposited coatings on the Ti13Nb13Zr alloy surface
    • Łukasz Pawłowski
    • Szymon Mania
    • Adrianna Banach-Kopeć
    • Karol Staszczyk
    • Aleksandra Mirowska
    • Aleksandra Mielewczyk-Gryń
    • Robert Tylingo
    2025 MATERIALS CHEMISTRY AND PHYSICS

    In this study, the effects of molecular weight (high, medium, and low), concentration (0.1 and 0.5 %) and dissolution method (in a rarely used hydroxyacetic acid and utilizing a novel CO2 saturation) of chitosan on the microstructure, chemical composition, wettability, surface roughness, adhesion, corrosion resistance and antibacterial activity of chitosan coatings electrophoretically deposited (10 V, 1 min) on β titanium alloy Ti13Nb13Zr were investigated. Microstructural analysis showed that low molecular weight chitosan at low concentrations formed uniform coatings while increasing these parameters resulted in uneven coatings with agglomerates. Energy-dispersive X-ray and Fourier transform infrared spectroscopy analyses confirmed the presence of chitosan on all coated samples. Higher concentrations of chitosan yielded thicker coatings. Wettability tests confirmed hydrophilic properties for all samples, with contact angles around 70°. Surface roughness varied with chitosan concentration, showing increased roughness for higher concentrations. Adhesion tests showed the highest critical load for high molecular weight chitosan coatings with a concentration of 0.1 %. Corrosion tests revealed that low molecular weight chitosan coatings provided the best protection. Antimicrobial assays showed that chitosan coatings prepared using acid dissolution had strong bactericidal activity against both Gram-positive and Gram-negative bacteria, while those prepared using CO2 saturation showed limited bacteriostatic activity. These findings suggest that chitosan coatings, especially those prepared using acid dissolution, hold promise for biomedical applications requiring corrosion resistance and antibacterial properties.

  • The influence of printing strategies on the fatigue crack growth behaviour of an additively manufactured Ti6Al4V Grade 23 titanium alloy
    • Rui F. Martins
    • Ricardo Branco
    • José Camacho
    • Wojciech Macek
    • Zbigniew Marciniak
    • António Silva
    • Cândida Malça
    2025 INTERNATIONAL JOURNAL OF FATIGUE

    The selective laser melting (SLM) process, a type of laser powder-bed fusion (LPBF) in additive manufacturing (AM), uses a high-power density laser to melt metallic powders. This study involved 3D printing Compact Tension (CT) specimens from titanium alloy Ti6Al4V, known for its rigidity, corrosion resistance, and biocompatibility, making it suitable for aerospace and medical applications. To predict fatigue life, it is essential to assess fatigue crack growth rates (FCGR) in the presence of cracks. This investigation tested three printing strategies − transversal, longitudinal, and cross − under constant amplitude loading (R = 0.2) and compared the results with reference titanium alloys. Scanning electron microscopy (SEM) was used to analyze the fracture surfaces. The results indicated that the as-built AM transversal CT specimens (R = 0.2) had superior FCGR compared to the longitudinal and cross specimens, closely matching those of SLM-produced Ti6Al4V heat-treated at 670 °C (R = 0.05). The transverse deposition mode yielded the best performance, with fracture surfaces exhibiting mainly transgranular propagation. In addition, fracture surface topography measurements showed a strong correlation with fatigue life, particularly the relationship between the mean depth of furrows and the number of cycles to failure.

  • The influence of selected metal oxides and laser modification on the surfaces of titanium alloys – Bibliometric and systematic review
    • Dominika Kwidzińska
    • Magdalena Jażdżewska
    • Dariusz Fydrych
    2025 OPTICS AND LASER TECHNOLOGY

    Manufacturing of oxide coatings (ZnO, ZrO2 , CuO) and laser processing are methods for modifying the surface of titanium and its alloys. It is particularly useful in implantology, where these techniques allow for proper connection of the implant to human tissue. The article consists of two complementary parts: a bibliographic review and a literature survey. The results of a bibliographic analysis conducted for a set of 429 publications indexed in the Web of Science (WOS) database regarding laser treatment of titanium and its alloys were pre sented. Using WOS, VOSviewer and Biblioshiny tools a comprehensive view of the development and dynamics of changes in the considered topics was determined and summarized. The most frequently discussed topics are aimed at determining structure–property relationships (microstructure, mechanical properties and corrosion resistance). The most active research centers and teams (from China, Poland, Germany, France) and journals (Surface Coatings Technology, Applied Surface Science, Materials) and the relationship between them are demonstrated. A systematic review of the literature shows that the surface properties of titanium are influenced by both the selected oxide and the method used to coat its surface. Literature analysis also indicated that a promising direction of research is to generate the synergy effect through processes using different surface modification methods. The ultimate goal of the article is not only the determination of gaps in the state of knowledge but also the identification of gaps requiring special research attention in future scientific works.

  • The interactions of Pu22 G-quadruplex, derived from c-MYC promoter sequence, with antitumor acridine derivatives – an NMR/MD combined study
    • Tomasz Laskowski
    • Michał Kosno
    • Witold Andrałojć
    • Julia Pakuła
    • Rafał Stojałowski
    • Julia Borzyszkowska-Bukowska
    • Ewa Paluszkiewicz
    • Zofia Mazerska
    2025 Molecular Therapy-Nucleic Acids

    Unsymmetrical bisacridines (UAs) represent a novel class of anticancer agents that exhibit significant antitumor activity against a wide range of cancer cell lines and solid tumors in vivo. UAs consist of two different acridine-based ring systems, which are connected by an aminoalkyl linker. Recent studies have demonstrated that UAs can suppress the c-MYC protooncogene, which is overexpressed in many tumor types. As a proposed molecular basis for this activity, UAs have been suggested to stabilize the G-quadruplex structure formed within the promoter region of c-MYC. In this study, we performed spectroscopic and computational analyses to investigate the stereochemistry of the c-MYC NHE III1 representative G-quadruplex, codenamed Pu22, in complex with two promising bisacridines, C-2045 and C-2053, as well as their monomeric counterparts, C-1311 and C-1748. C-1311 formed a well-defined 1:2 mol/mol DNA:ligand non-covalent adduct, whose solution structure was determined via 2D NMR. In contrast, C-1748 displayed weak and nonspecific interactions with the Pu22 G-quadruplex. Finally, the Pu22:UAs complexes were examined using a combination of NMR and molecular modeling approaches, including umbrella sampling simulations. These results provide insights into the interaction mechanisms of UAs with G-quadruplex structures and highlight their potential as therapeutic agents targeting c-MYC.

  • The Laser Processing of the Stainless-Steel Surface Layer of a Heat Exchanger Membrane in Order to Enhance Its Heat Transfer Coefficient
    • Ewa Kozłowska
    • Marek Szkodo
    • Tomasz Muszyński
    • Paulina Adamska
    2025 Coatings

    Research on temperature regulation is essential for ensuring thermal comfort and optimizing machine performance. Effective cooling systems are critical in industrial processes and everyday electronic devices in order to prevent overheating. Laser-modified heat exchangers can enhance heat dissipation without increasing weight, addressing the need for energy-efficient solutions in the market. The main aim of this experimental research was to establish an efficient method for altering the surface layer of AISI 316L stainless steel with laser pulses and to determine the effectiveness of the laser alterations to the surface layer in the context of intensifying the convective heat transfer. A series of laser-texturing processes was performed on the surface layer of AISI 316L steel using a Nd: YAG pulse laser. Selected samples were subjected to a series of measurements using a recuperator-type heat exchanger. Based on the measurements’ results, the heat transfer coefficients, α, obtained from the modified surfaces were determined. The results were compared with other data from the existing literature and those obtained from unmodified reference samples. The intensification of the convective heat transfer was achieved for 43% of the modifications conducted with a pulsed laser. The highest observed average increase in the heat transfer coefficient, α, was 16.53%. However, the effective intensification of the convective heat transfer, in some cases, was only observed for a certain range of temperatures or flow dynamics parameters.

  • The role of nanomaterials in tailoring electromembrane extraction performance: A review
    • Wajid Ali Khan
    • Muhammad Balal Arain
    • Stig Pedersen-Bjergaard
    • Hameed Ul Haq
    • Roberto Castro Munoz
    • Grzegorz Boczkaj
    2025 TALANTA.The International Journal of Pure and Applied Analytical Chemistry

    Electromembrane extraction (EME) is a membrane-based miniaturized microextraction technique used to extract ionized analytes from complex mixtures. EME extracts can be analyzed using all major analytical instrumental techniques. The major advantages of EME include short extraction time, low consumption of organic solvents and chemicals, high extraction capability, high selectivity, and efficient sample cleanup. Numerous modifications to EME, such as the use of microfluidic devices, green solvents, biobased renewable membranes, and hyphenation with other separation techniques, have increased the selectivity and sensitivity of EME. Furthermore, nanomaterials have been used to improve the efficiency, selectivity, and stability of EME systems. Various nanomaterials have been proposed for the modification of EME-based separation systems. The larger surface area, high porosity, and various interactions with the target analytes are the most important properties of nanomaterials and nanocomposites in improving the figures of merit of EME. Nanomaterials have mainly been used to modify the chemical composition of the liquid membrane in EME, but modifications of the polymeric support membrane and the electrodes have also been reported. Therefore, this review highlights the transformative role of nanomaterials in EME, focusing on their application in enhancing extraction efficiency, selectivity, and stability. Key advancements include modifying supported liquid membranes (SLMs), membrane decoration, and optimizing electrode performance. The review also critically examines challenges, such as pore blockage and electrolysis-induced instability, offering insights into future directions for nanomaterial-enhanced EME. Despite of the numerous benefits of nanomaterials, their environmental toxicity cannot be overlooked and should be carefully examined for each new case. A bio-based and biopolymer-based nanomaterials in future EME studies can significantly address these issues while remaining aligned with green chemistry principles. Artificial intelligence-based models should be applied to predict effective nanomaterials in EME, thus significantly reduce chemical costs and consumption while also increasing the greenness level of developed EME approaches. Finally, long-term stability of new developed solutions should be an obligatory part of each new research in this field.

  • The solvent-assisted dispersive solid-phase extraction method revisited. Application for the determination of anionic surfactants
    • Serhii Zaruba
    • Patrycja Makoś-Chełstowska
    • Vasil Andruch
    2025 Advances in Sample Preparation

    A new approach in solvent-assisted dispersive solid-phase extraction (SA-DSPE) procedure using a supercooled liquid was developed. It demonstrates the first use of a supercooled liquid in this technique, in particular, and in chemical analysis in general. Moreover, to the best of our knowledge, this is the first work devoted to the determination of the total concentration of anionic surfactants (as LAS, Linear alkylbenzene sulfonate) using a micro-SPE technique. The method is based on the formation of an ion pair between astraphloxine (cationic dye) and an anionic surfactants, with subsequent extraction of the ion pair formed onto a benzophenone sorbent generated in situ after injection of its 5 % solution in an acetone:water 80:20 v/v mixture into an aqueous sample. The resulting turbidness was sedimented by centrifugation. The addition of a few crystals of benzophenone then leads to the solidification of a supercooled solution of the sorbent, which facilitates the separation. Afterwards, the bulk of the aqueous phase was easily decanted, and the resulting sediment was dissolved with 500 μL of acetone; absorbance measurements were carried out in a semi-microcuvette. The calibration plot was linear up to 0.5 µmol L−1 of sodium dodecylbenzene sulfonate (SDBS). The LOD and LOQ, were 9.0 and 30 nmol L-1 of SDBS, respectively. The developed procedure was applied for the determination of anionic surfactants in various real water samples.

  • The strategies of nutrient removal compounds from wastewater by using aquatic plants in the Green deal implementation
    • Larysa Sablii
    • Veronika Zhukova
    • Jakub Drewnowski
    2025 Full text Desalination and Water Treatment

    The aim of the study was to determine the efficiency of wastewater treatment from nitrogen compounds - ammonium, nitrite, nitrate, and phosphate - using Lemna minor and Spirogyra sp. in the context of the strategies toward Green Deal Implementation. Meanwhile, the various biological treatment methods of nutrients according to the value-added and application prospects were also discussed as a future solution in the Circular Economy Model. The complementary effect of Lemna minor and other higher aquatic plants, in particular Spirogyra sp. was established. The efficiency of nitrate removal for 7 days was 86.4 %, andphosphate removal was 78 %. The concentration of NO3 - ions after treatment was 6.8 mg/dm3, and phosphate (P2O5) 2.2 mg/dm3. It was noted that the simultaneous use of an increased dose of duckweed Lemna minor and the algae Spirogyra sp. significantly increases the efficiency of nitrate removal from the experimental samples, and the efficiency of phosphate removal did not change compared to the experiment without the use of the algae Spirogyra sp. and with the use of a double dose of duckweed. Under these conditions, the nitrate removal efficiency for a duration of 7 days was 92 % and the phosphate removal efficiency was 80 %. The concentration of NO3 - ions after treatment was 4 mg/ dm3, and phosphate (P2O5) 2 mg/dm3.

  • The tensile strength of different methods of anterior cruciate ligament graft end stitches in an animal model
    • Marcin Dembski
    • Patryk Kawa
    • Jakub Tarnawski
    • Marcin Ceynowa
    • Krzysztof Żerdzicki
    • Paweł Kłosowski
    2025 Full text KNEE

    Background: There are several methods for stitching graft ends in anterior cruciate liga-ment reconstructive surgery. The tendon-suture construct should be able to withstand ten-sioning until the graft is stabilized with an implant. Methods: In this biomechanical study, 40 porcine lower extremity tendons ends were stitched with No. 2 suture, secured to the grips of the Zwick-Roell testing machine and tested for load at failure and type of failure (tendon v/s suture thread). The applied force was linear, the results are given in Newtons (N) as a mean. The Mann-Whitney U test was used for statistical analysis. The following constructs were compared: a whipstitch of each tendon end individually with 3, 4, and 5 passes through the tendon, a whipstitch of both tendon ends folded together and a tendon end knot without stitching. Results: All specimens survived the minimum tensile load of 80 N. The load at failure for whipstitch with 3,4 and 5 passes were 175 N, 211 N and 254 N respectively. The load at failure was greater for individual whipstitch than for both ends folded together (261 N v/s 152 N). The mean load at failure for braided graft was 209 N. The braided graft slips off the tendon before failure leading to uneven strength distribution during tensioning. Conclusion: Increasing number of suture passes resulted in higher load at failure. Individual tendon ends whipstitched with 5 passes was the strongest construct. All of the investigated techniques are sufficient to withstand the suggested optimal graft tension of 80 N.

  • Theoretical design of nanocatalysts based on (Fe2O3)n clusters for hydrogen production from ammonia
    • Sapajan Ibragimov
    • Andrey Lyalin
    • Sonu Kumar
    • Yuriko Ono
    • Tetsuya Taketsugu
    • Maciej Bobrowski
    2025 Full text JOURNAL OF CHEMICAL PHYSICS

    The catalytic activities of high-spin small Fe(III) oxides have been investigated for efficient hydrogen production through ammonia decomposition, using the artificial force induced reaction method within the framework of density functional theory with the B3LYP hybrid exchange–correlation functional. Our results reveal that the adsorption free energy of NH3 on (Fe2O3 )n (n = 1–4) decreases with increasing cluster size up to n = 3, followed by a slight increase at n = 4. The strongest NH3 adsorption energy, 28.55 kcal/mol, was found for Fe2O3 , where NH3 interacts with a two-coordinated Fe site, forming an Fe–N bond with a length of 2.11 Å. A comparative analysis of NH3 dehydrogenation and H2 formation on various Fe(III) oxide sizes identifies the rate-determining steps for each reaction. We found that the rate-determining step for the full NH3 dehydrogenation on (Fe2 O3 )n (n = 1–4) is size-dependent, with the NH* → N* + H* reaction acting as the limiting step for n = 1–3. In addition, our findings indicate that H2 formation is favored following the partial decomposition of NH3 on Fe(III) oxides.

  • Thermal affection on hydrogen diffusion in different structures of nickel alloy
    • Pasquale Cavaliere
    • Behzad Sadeghi
    • Chen Zhenghan
    • Alicja Stanisławska
    2025 Multidiscipline Modeling in Materials and Structures

    Purpose Based on previous research, we choose nickel alloy 718 as the research material and use finite element analysis (FEA) to simulate the hydrogen diffusion in lattice, grain, boundary grain and dislocation in different thermal loads, aiming to understand the intricate mechanisms underlying hydrogen diffusion in nickel-based alloys, which will contribute to driving progress in the field of hydrogen diffusion for understanding and management HE. Design/methodology/approach In this research, we focus on nickel alloy 718, creating a numerical model with traps to simulate the hydrogen diffusion in lattice, grain, boundary grain and dislocation with different thermal loads, by FEA. Findings The results demonstrated that traps improve the hydrogen saturation in materials, and because of thermal saturation and heat flux, higher temperatures decrease the hydrogen solubility and increase hydrogen diffusion velocity, which can decrease hydrogen saturation. Originality/value Based on our previous research and publications, we developed a finite element model to define the hydrogen trapping in different microstructural features of nickel-based superalloys. The model is very complex with a very large number of elements capable of obtaining very affordable results.