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Gdańsk University of Technology

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  • User Orientation Detection in Relation to Antenna Geometry in Ultra-Wideband Wireless Body Area Networks Using Deep Learning
    • Sebastian Urwan
    • Krzysztof Cwalina
    2024 Full text SENSORS

    In this paper, the issue of detecting a user’s position in relation to the antenna geometry in ultra-wideband (UWB) off-body wireless body area network (WBAN) communication using deep learning methods is presented. To measure the impulse response of the channel, a measurement stand consisting of EVB1000 devices and DW1000 radio modules was developed and indoor static measurement scenarios were performed. It was proven that for the binary classification of user orientation, neural networks achieved accuracy that was more than 9% higher than that for the well-known threshold method. In addition, the classification of user position angles relative to the reference node was analyzed. It was proven that, using the proposed deep learning approach and the channel impulse response, it was possible to estimate the angle of the user’s position in relation to the antenna geometry. Absolute user orientation angle errors of about 4–7◦ for convolutional neural networks and of about 14–15◦ for multilayer perceptrons were achieved in approximately 85% of the cases in both tested scenarios.

  • User-oriented GIS tools in higher education of urban design and planning
    • Weronika Maria Mazurkiewicz
    • Anna Kaczorowska
    • Anna Rubczak
    • Justyna Wieczerzak
    • Dorota Dominika Kamrowska-Załuska
    2024 Full text World Transactions on Engineering and Technology Education

    Geographic information systems (GIS) have emerged as indispensable tools for decision-making, planning and problem-solving tasks across various domains in today’s evolving world. However, there exists a pressing need to augment the utilisation of GIS tools in higher education of urban design and planning to foster a user-oriented approach. This article explores the imperative of integrating GIS tools more comprehensively into higher education curricula to empower students with the skills necessary to leverage geographic information effectively. Selected cases from the Programmes of Architecture and Spatial Development at Gdańsk University of Technology (Gdańsk Tech), Poland, and Physical Planning at the Norwegian University of Science and Technology (NTNU), Trondheim, Norway, demonstrate students’ experience with user-oriented GIS tools. Results reveal there is a growing demand in higher education to integrate GIS tools into service design approaches and participatory practice. Enhancing access to GIS technologies for students and stakeholders will encourage collaboration between education and practice, facilitating real-time adjustments and crossdisciplinary efforts.

  • Utilizing Morphological and Physiological Parameters of Lemna minor for Assessing Tetracyclines’ Removal
    • Łukasz Sikorski
    • Agnieszka Bęś
    • Kazimierz Warmiński
    • Wojciech Truszkowski
    • Przemysław Kowal
    2024 MOLECULES

    Antibiotics with significant environmental toxicity, e.g., tetracyclines (TCs), are often used in large quantities worldwide, with 50–80% of the applied dose ending up in the environment. This study aimed to investigate the effects of exposure to tetracycline hydrochloride (TC) and minocycline hydrochloride (MIN) on L. minor. Our research evaluated the phytotoxicity of the TCs by analyzing plant growth and biomass and evaluating assimilation pigment levels and fluorescence. The research was extended with the ability potential of duckweed as a tool for removing TCs from water/wastewater. The results demonstrated that both TCs influenced Ir, Iy, biomass, and photosynthetic efficiency. The uptake of TC and MIN by duckweed was proportional to the concentration in the growth medium. The TC was absorbed more readily, reaching up to 8.09 mg × g−1 of dry weight (DW) at the highest concentration (19.2 mg × L−1), while MIN reached 6.01 mg × g−1 of DW. As indicated, the consequences of the influence of TC on plants were slightly smaller, in comparison to MIN, while the plants could biosorb this drug, even at the lowest tested concentration. This study has shown that using plants for drug biosorption can be an effective standalone or complementary method for water and wastewater treatment.

  • UV-assisted fluctuation-enhanced gas sensing by ink-printed MoS2 devices
    • Katarzyna Drozdowska
    • Janusz Smulko
    • Jakub Czubek
    • Sergey Rumyantsev
    • Andrzej Kwiatkowski
    2024 Full text Scientific Reports

    In this work, MoS2 flakes were printed on ceramic substrates and investigated toward 1–10 ppm of nitrogen dioxide (NO2), 2–12 ppm of ammonia (NH3), and 2–12 ppm acetone (C3H6O) under UV light (275 nm). The structure of overlapping MoS2 flakes and UV light assistance affected high responsivity to NO2 when DC resistance was monitored, and superior sensitivity to NH3 was obtained from the low-frequency noise spectra. MoS2 exhibited response and recovery times in hundreds of seconds and stability throughout the experiments conducted within a few months. MoS2 sensor exhibited a resistance drift during the detection of a specific relaxation time. Subtracting the baseline burden with exponential drift exposed the direction of changes induced by oxidizing and reducing gases and reduced DL to 80 ppb, 130 ppb, and 360 ppb for NO2, NH3, and C3H6O, respectively. The fluctuation-enhanced sensing (FES) revealed that the adsorption of NO2 on MoS2 decreases the noise intensity, whereas adsorbed NH3 increases the fluctuations of current flowing through the sensor, and these changes are proportional to the concentration of gases. The noise responses for NO2 and NH3 were opposite and higher than DC resistance responses with subtracted baseline (an increase of 50% for 10 ppm of NO2 and an increase of more than 600% for 12 ppm of NH3), showing that FES is a highly sensitive tool to detect and distinguish between these two gases. This way, we introduce a simple and low-cost method of gas sensor fabrication using ink-printed MoS2 and the possibility of enhancing its sensitivity through data processing and the FES method.

  • Vaccinium Species—Unexplored Sources of Active Constituents for Cosmeceuticals
    • Wirginia Kukuła-Koch
    • Natalia Dycha
    • Paulina Lechwar
    • Magdalena Lasota
    • Estera Okoń
    • Paweł Szczeblewski
    • Anna Wawruszak
    • Dominik Tarabasz
    • Jane Hubert
    • Piotr Wilkołek
    • Maria Halabalaki
    • Katarzyna Gaweł-Bęben
    2024 Biomolecules

    The genus Vaccinium is represented by shrubs growing in a temperate climate that have been used for ages as traditional remedies in the treatment of digestive problems, in diabetes, renal stones or as antiseptics due to the presence of polyphenols (anthocyanins, flavonoids and tannins) in their fruits and leaves. Recent studies confirm their marked potential in the treatment of skin disorders and as skin care cosmetics. The aim of this review is to present the role of Vaccinium spp. as cosmetic products, highlight their potential and prove the biological properties exerted by the extracts from different species that can be useful for the preparation of innovative cosmetics. In the manuscript both skin care and therapeutic applications of the representatives of this gender will be discussed that include the antioxidant, skin lightening, UV-protective, antimicrobial, anti-inflammatory, and chemopreventive properties to shed new light on these underestimated plants.

  • Validation of dynamic electrochemical impedance spectrograms using autocorrelation function
    • Kazimierz Darowicki
    • Szymon Wysmułek
    • Anna Karólkowska
    • Łukasz Gaweł
    2024 JOURNAL OF ELECTROANALYTICAL CHEMISTRY

    Validation of impedance data is essential for checking the reliability of experimental data. Kramers – Kronig transformation is used to verify data obtained from classical Electrochemical Impedance Spectroscopy (EIS) measurements. Data obtained from Dynamic Electrochemical Impedance Spectroscopy (DEIS) could be validated in the same way, but in this case, there is no information about internal consistency between every single spectrum in the whole spectrogram. To address these challenges, the authors proposed an approach using the autocorrelation function ACF to validate DEIS time series. The reasoning conducted showed that ACF function is appropriate tool for validating DEIS spectrograms.

  • Valorization of paper-mill sludge laden with 2-chlorotoluene using hydroxyapatite@biochar nanocomposite to enrich methanogenic community: A techno-economic approach
    • Rania H. Hafez
    • Ahmed Tawfik
    • Gamal K. Hassan
    • Magdy Zahran
    • Ahmed A. Younes
    • Aleksandra Ziembińska-Buczyńska
    • Filip Gamoń
    • Mahmoud Nasr
    2024 BIOMASS & BIOENERGY

    While several studies have investigated the anaerobic digestion of paper-mill sludge (PMS), this technology suffers from nutrient insufficiency, inhibition by aromatic compounds, and low bio-CH4 yield. Hence, PMS was anaerobically co-digested with chicken manure (CM) and supplemented by hydroxyapatite@biochar (HAP@BC) nanocomposite for enhancing 2-chlorotoluene degradation and enriching the methanogenic archaea. Multiple continuous stirred tank reactors (CSTRs) were operated at 12.6 h hydraulic retention time (HRT), using PMS (R1), CM (R2), PMS + CM (R3), PMS + CM+100 mg HAP/L (R4), and PMS + CM+100 mg HAP@BC/L (R5). The maximum bio-CH4 yield of 147.5 ± 9.1 mL/g COD and 2-chlorotoluene removal of 91.2 ± 6.8 % were obtained from R5, experiencing a sufficient C/N ratio of 14.7 and the highest activities of acidogenesis (42.0 %), aceto- genesis (37.9 %), and methanogenesis (42.1 %). The abundances of Euryarchaeota, Bacteroidota, and Chloroflexi at the phylum level, and Pseudomonas, and Bacillus at the genus level could highly contribute to the dechlori- nation mechanism and acetate transformation into CH4. This biomass-to-bioenergy project (10 m3/d capacity) could benefit from pollution reduction, biogas recovery, and carbon credit, giving 5.6 yr payback-period, 3503 USD net present value, and 12.1 % internal rate of return. Because R5 exhibited an efficient techno-economic anaerobic biodegradation performance, future studies are required to optimize its HRT condition and HAP@BC dosage.

  • Value co‐creation (VCC) and value co‐destruction (VCD) via open government data (OGD): Empirical case of Tanzania
    • Fredrick Ishengoma
    • Deo Shao
    • Raphael Gouvea da Silva
    • Guillherme Costa Wiedenhoft
    • Charalampos Harris Alexopoulos
    • Nina Rizun
    • Stuti Saxena
    2024 Electronic Journal of Information Systems in Developing Countries

    Having emphasized upon the potential benefits of Open Government Data (OGD) initiatives via value derivation and innovation pursuits of the stakeholders, it falls in place to complement this line of OGD research in the specific case of Tanzania, a developing country, to support the inferences. Specifically, it is important to understand the manner in which OGD VCC-one of the hinges of OGD initiatives- and OGD VCD-a possible fall out of OGD initiatives- happens to pass. Thus, a content analysis of the interviews of 15 public officials and managers was conducted to arrive at its conclusions. Thus, the interviewees aver that OGD Value Co-creation (VCC) may be facilitated on top-priority bases by consistent marketing efforts by the government as also the partnerships with the key stakeholders of the OGD ecosystem, and, among the prominent Value Co-Destruction (VCD) factors may be counted the issues linked with data privacy and resource restriction. Literature on OGD VCC is at a nascent stage and the one on OGD VCD is evolving. As an atypical empirical validation case vis-a-vis the emerging OGD VCC-VCD research, the study is an additional contribution to the extant literature with specific reference to the developing country's experiences where the OGD initiatives are at an evolving stage

  • Variable Data Structures and Customized Deep Learning Surrogates for Computationally Efficient and Reliable Characterization of Buried Objects
    • Reyhan Yurt
    • Hamid Torpi
    • Ahmet Kizilay
    • Sławomir Kozieł
    • Peyman Mahouti
    2024 Full text Scientific Reports

    In this study, in order to characterize the buried object via deep-learning-based surrogate modeling approach, 3-D full-wave electromagnetic simulations of a GPR model has been used. The task is to predict simultaneously and independent of each characteristic parameters of a buried object of several radii at different positions (depth and lateral position) in various dispersive subsurface media. This study has analyzed variable data structures (raw B-scans, extracted features, consecutive A-scans) with respect to computational cost and accuracy of surrogates. The usage of raw B-scan data and the applications for processing steps on B-scan profiles in the context of object characterization incur high computational cost so it can be a challenging issue. The proposed surrogate model referred to as the deep regression network (DRN) is utilized for time frequency spectrogram (TFS) of consecutive A-scans. DRN is developed with the main aim being computationally efficient (about 13 times acceleration) compared to conventional network models using B-scan images (2D data). DRN with TFS is favorably benchmarked to the state-of-the-art regression techniques. The experimental results obtained for the proposed model and second-best model, CNN-1D show mean absolute and relative error rates of 3.6mm, 11.8mm and 4.7%, 11.6% respectively. For the sake of supplementary verification under realistic scenarios, it is also applied for scenarios involving noisy data. Furthermore, the proposed surrogate modeling approach is validated using measurement data, which is indicative of suitability of the approach to handle physical measurements as data sources.

  • Variable Resolution Machine Learning Optimization of Antennas Using Global Sensitivity Analysis
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2024 Full text Scientific Reports

    The significance of rigorous optimization techniques in antenna engineering has grown significantly in recent years. For many design tasks, parameter tuning must be conducted globally, presenting a challenge due to associated computational costs. The popular bio-inspired routines often necessitate thousands of merit function calls to converge, generating prohibitive expenses whenever the design process relies on electromagnetic (EM) simulation models. Surrogate-assisted methods offer acceleration, yet constructing reliable metamodels is hindered in higher-dimensional spaces and systems with highly nonlinear characteristics. This work suggests an innovative technique for global antenna optimization embedded within a machine-learning framework. It involves iteratively refined kriging surrogates and particle swarm optimization for generating infill points. The search process operates within a reduced-dimensionality region established through fast global sensitivity analysis. Domain confinement enables the creation of accurate behavioral models using limited training data, resulting in low CPU costs for optimization. Additional savings are realized by employing variable-resolution EM simulations, where low-fidelity models are utilized during the global search stage (including sensitivity analysis), and high-fidelity ones are reserved for final (gradient-based) tuning of antenna parameters. Comprehensive verification demonstrates the consistent performance of the proposed procedure, its superiority over benchmark techniques, and the relevance of the mechanisms embedded into the algorithm for enhancing search process reliability, design quality, and computational efficiency.

  • Vehicle type recognition: a case study of MobileNetV2 for an image Classification task
    • Dariusz Kobiela
    • Jan Groth
    • Michał Hajdasz
    • Mateusz Erezman
    2024 Procedia Computer Science

    The goal of the research was to demonstrate the full data science lifecycle through a use case of the MobileNetv2 model for vehicle image Classification task using various validation and test sets, each with different difficulty level. Diverse model variations were employed, each designed to recognize images of ground vehicles and classify them into one of five possible classes: car, truck, motorcycle, bicycle, or bus. In terms of validation accuracy, the highest results were obtained by the model trained with uniformly designed train and val sets (with data normalization and augmentation), where train set also contained validation set. This model also obtained the highest accuracy results on both test sets. The superiority of MODEL 3 BASELINE is confirmed by other metrics as well: test loss, f1-score, AUC and confusion matrices (for both test sets). Results between MODEL 1 BASELINE and MODEL 2 BASELINE differed according to the test set 1 and 2 and other metrics and it was not possible to declare the superiority of one method of datasets preparation over another (original class distribution [no data normalization and no data augmentation] versus uniformly designed [with data normalization and augmentation]). The article also presents challenges and findings - the problems, key issues, and their solutions that arose during the process of data collection and tagging, as well as the preparation and evaluation of the model.

  • Versatile Unsupervised Design of Antennas Using Flexible Parameterization and Computational Intelligence Methods
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Stanisław Szczepański
    2024 Full text Scientific Reports

    Developing contemporary antennas is a challenging endeavor that requires considerable engineering insight. The most laborious stage is to devise an antenna architecture that delivers the required functionalities, e.g., multiband operation. Iterative by nature (hands-on topology modifications, parametric studies, trial-and-error geometry selection), it typically takes many weeks and requires considerable engagement from a human expert. Consequently, only a few possible design options concerning the fundamental antenna geometry may be considered. Automated topology rendition and geometry parameter optimization are highly relevant, especially from the industrial perspective. Therein, reducing time-to-market and limiting the involvement of trained experts is critical. This research proposes an innovative procedure for unsupervised development of planar antennas. Our method leverages flexible antenna parameterization based on re-sizable elliptical patches. It permits the realization of a massive number of geometries of diverse shapes and complexities using a small number of decision variables. Computational intelligence methods are employed to conduct antenna evolution exclusively based on specifications and possible constraints (e.g., maximum size). Fine-tuning of the structure geometry is achieved through low-cost local search routines. Our methodology is demonstrated by designing several antennas featuring distinct characteristics (broadband, single-, dual- and triple-band). The obtained results, supported by experimental data, underscore the presented approach’s versatility and capability to render unconventional topologies at reasonably low computational expenses. As mentioned earlier, the design process is fully automated without human expert involvement.

  • Virtual Escape Room in Mathematics
    • Radosław Baziak
    • Tomasz Daruk
    • Karol Żyra
    • Dorota Żarek
    • Jacek Lebiedź
    2024

    The paper presents developing a virtual reality-based escape room to teach mathematical concepts. The goal was to create an immersive game to engage students in actively solving math puzzles. The research team built the application for use in the Immersive 3D Visualization Lab at the Gdańsk University of Technology. The escape room comprises an introductory room followed by three themed rooms with 13 puzzles total that involve mathematical thinking. To assess the tool’s educational impact, the team prepared surveys and planed an experiment with students. Key outcomes delivered were the completed application configured for the target lab, plus the surveys to quantitatively measure math comprehension before and after students use the escape room. Overall this project combined virtual reality and game design concepts to create an innovative approach for engaging students in learning math concepts in an interactive, visually stimulating setting.

  • Virtual tour as an innovative tool for architectural education - from understanding heritage to creativity stimulation
    • Karolina Życzkowska
    • Doria Elisabetta
    • Justyna Borucka
    2024 World Transactions on Engineering and Technology Education

    The article presents the potential of the virtual tour in architectural education as an innovative tool to better understand heritage and stimulate creativity. A methodology for creating a virtual tour based on a point cloud obtained from a survey based on 360° camera images is presented. Two different purposes for the use of point clouds are presented from reliable indicators of heritage documentation useful for digital twin modelling and architectural analysis, to the creation of thematic virtual tours enabling the testing of different scenarios. The article focuses on the case of virtual tours that were created as part of the 2023 Gdańsk Summer School associated with the H2020 PROMETHEUS project, in collaboration between Gdańsk University of Technology (Gdańsk Tech), Poland, and the University of Pavia, Italy. A virtual tour was created for a significant part of the Royal Way in Gdańsk. A comparison of the different types of virtual tours is presented in relation to their objectives (educational, tourist, entertainment), the characteristics of the scenarios (place, time, story, characters) and the experience environment (virtual, augmented or immersive space).

  • Vitamin B9 as a new eco-friendly corrosion inhibitor for copper in 3.5% NaCl solution
    • Hubert Kwiatkowski
    • Stefan Krakowiak
    • Łukasz Gaweł
    2024 Full text JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY

    Folic acid salt (sodium folate) was studied as an eco-friendly and non-toxic copper corrosion inhibitor in 3.5% NaCl solution. Electrochemical impedance spectroscopy, polarization resistance and weight-loss measurements show that the inhibitor efficiency increases with concentration (the highest value- approx. 96% was reported for the solution containing 16 mM sodium folate after 24 h). EIS data and Tafel plots indicate that sodium folate is a barrier, mixed-type (with predominant cathodic character) inhibitor. Inhibitor efficiency decreases with temperature, which suggests that adsorption has physical character rather than chemical one - adsorption free energy calculated using the Langmuir model is consistent with this statement. Activation energy determined from the Arrhenius plot increases as a result of inhibitor presence. Efficiency of the inhibitor increases systematically during the first 12 hours of immersion. Potential chemical changes in sodium folate solution were investigated using UV-VIS spectroscopy. Furthermore, copper surface after immersion in the presence and absence of inhibitor was characterized with scanning electron microscopy, energy-dispersive X-Ray spectroscopy and microscopic photographs.

  • Voltage and Current Unbalance Reduction in Power Networks with Distributed Generation and Electric Vehicles
    • Krzysztof Dobrzyński
    • Stanisław Czapp
    2024 Full text ENERGIES

    The current development of prosumer microsources and the expected spread of electric vehicles may cause the appearance of significant current and voltage unbalance in low-voltage (LV) networks. This unbalance, which is an unfavorable phenomenon, may occur when using single-phase photovoltaic (PV) microsources and single-phase home chargers for electric vehicles. This paper presents a proposal for the symmetrization of the LV network using devices for the reconfiguration of phases in the power supply. Both the different locations of these devices and the different objective functions for device implementation are analyzed. The research was carried out on an example LV network, taking into account several variants of the development of PV microsources and home chargers for electric vehicles. The analysis indicates that the appropriate location of phase reconfiguration devices and the use of an appropriate objective function leads to a significant reduction in unfavorable unbalancing in the LV network.

  • Voltage Control of a Stand-Alone Multiphase Doubly Fed Induction Generator
    • Krzysztof Blecharz
    • Marcin Morawiec
    • Roland Ryndzionek
    • Michał Michna
    2024 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    This article presents a multiphase doubly fed induction generator (MDFIG) with a dedicated and unique control algorithm in a stand-alone wind energy conversion system. The algorithm has been developed and elaborated in the case of different emergency modes. Compared with the traditional double-fed induction generator, the MDFIG has increased reliability, reduced current level per phase, and low rotor harmonic currents. The control system is based on a classical mathematical model and the stator field-oriented control method. However, especially for the wind turbine system, the control system has been extended for dedicated five-phase operation and additional scenarios have been added. First, the dynamic states of the generator operation under normal operating conditions with voltage variation and load were simulated and compared with laboratory tests. Second, the fault-tolerance results of rotor phase failures with different states and loads were presented. This performance is validated in the laboratory with a 4 kW prototype MDFIG. The method presented in this article is simple, robust, and cost effective with MDFIG and has significantly improved the reliability of the power generation system.

  • Walther H. Nernst - noblista z Wąbrzeźna
    • Adam Barylski
    2024 Przegląd Techniczny

    Przedstawiono życiorys i osiągnięcia naukowe prof. Walthera Hermanna Nernsta, urodzonego 25 czerwca 1864 r. w Wąbrzeźnie, laureata Nagrody Nobla z dziedziny chemii z roku 1921. W. Nernst jest autorem m.in. III zasady termodynamiki oraz konstruktorem tzw. lampy Nernsta. Była to jedna z pierwszych lamp elektrycznych, oświetlająca wieżę Eiffla i pawilon niemiecki na Światowej Wystawie w Paryżu w 1890 r. W roku 1914 zostaje honorowym doktorem politechniki w Gdańsku. W roku 1991 na domu w którym się urodził w Wąbrzeźnie umieszczono tablicę pamiątkową, podobnie jak w roku 2021 na murach szkoły w Grudziądzu, do której uczęszczał. W 120-lecie Politechniki Gdańskiej z uznaniem warto wspomnieć postać profesora, mniej nam znanego niż jego osiągnięcia naukowe.

  • Warstwowa ocena epidemiologiczna architektury zakładów opiekuńczo-leczniczych i zakładów gieriatycznych = Layer based epidemiological quality assessment of architecture of care security and geriatric wards
    • Wacław Szarejko
    • Rafał Janowicz
    2024 MEDYCYNA PRACY

    W artykule opisano możliwość wykorzystania autorskiej metody warstwowej oceny epidemiologicznej (WOE) do oceny potencjalnego ryzyka zakażeń w obiektach przeznaczonych dla osób starszych. Materiał i metody: W celu weryfikacji możliwości użycia metody WOE do oceny zagrożeń w zakresie bezpieczeństwa epidemiologicznego środowiska zbudowanego poddano analizie dostępne źródła literatury związane z obowiązującymi w Polsce wymaganiami prawnymi w zakresie oceny ergonomii obiektów medycznych pod względem transmisji zakażeń. W artykule odniesiono się również do wytycznych Komisji Europejskiej w zakresie Nowego Europejskiego Bauhausu i systemu oceny jakości Davos Baukultur Quality System jako standaryzowanej metody oceny jakości przestrzeni zbudowanej. W pracy przedstawiono podstawowe założenie autorskiej metody WOE pozwalającej na ocenę ryzyka transmisji zakażeń oddzielnie dla poszczególnych grup elementów, z których składa się budynek. Skuteczność metody wykazano poprzez wykorzystanie jej do oceny ryzyka zakażeń na przykładzie pokoju oddziału geriatrycznego. Wyniki: W artykule pokazano możliwość zastosowania narzędzia warstwowej oceny struktury budynku jako skutecznej metody wspomagającej działania ograniczające ryzyko epidemiczne. Wykorzystanie WOE umożliwia czytelne rozróżnienie potencjalnych dróg zakażeń w obrębie analizowanych obiektów i przyporządkowanie ich poszczególnym elementom składowym budynków. Dodatkowo przedstawiona metoda umożliwia zdefiniowanie koniecznych do wykonania procedur i opracowanie schematu działań minimalizujących ryzyko rozprzestrzenienia zakażeń w obrębie analizowanych nieruchomości. Wnioski: Zastosowanie WOE do oceny rozwiązań architektonicznych obiektów przeznaczonych do pobytu osób starszych wiąże się z wieloma korzyściami. Metoda ta może stanowić narzędzie eksperckie pozwalające na szybką i precyzyjną ocenę potencjalnych zagrożeń epidemiologicznych. Ważną zaletą jest także możliwość wykorzystania jej, w sposób odrębny, w przypadku różnorodnych typów zagrożeń epidemiologicznych cechujących się różnymi drogami transmisji zakażeń

  • Water retention curves of sandy soils obtained from direct measurements, particle size distribution, and infiltration experiments
    • Umar Farooq
    • Wioletta Gorczewska-Langner
    • Adam Szymkiewicz
    2024 VADOSE ZONE JOURNAL

    Accurate information about soil water retention curves (SWRCs) of sands is essential for evaluating groundwater recharge and vulnerability to contamination in many shallow sandy aquifers which are widespread on post glacial areas in Northern Europe and North America. Pedotransfer functions (PTFs) allow to estimate SWRC from basic physical characteristics of soils, such as textural composition. However, in the case of clean sands which are dominated by a single textural fraction, PTFs should be based on more detailed information given by the particle size distribution. In this study we evaluated three parametric PTFs, which estimate parameters of the van Genuchten SWRC based on empirical correlations to the parameters of soil particle size distribution, and five semi-physical PTFs, which derive the pore size distribution from particle size distribution. PTFs were compared to SWRCs fitted to the results of drainage experiments on sandy soil samples from six locations in Gdańsk region (northern Poland). Although in all samples the content of silt and clay fractions was low (<3.5%), the differences in actual content of fines strongly influenced the shape of SWRC. In contrast, the amount of gravel fraction (varying from 1% to 35%) did not have significant effect on SWRC. Semi-physical PTFs were found to be more accurate than parametric PTFs. The best overall performance was shown by the semi-physical Chang and Cheng PTF. Among the parametric PTFs the best accuracy was obtained with the Schaap and Bouten method. However, all considered functions showed limited accuracy in higher suction range. Additionally, infiltration experiments were performed on four sites. SWRCs were obtained from ring infiltrometer tests using the Beerkan estimation of soil transfer parameters (BEST) method and from the tension infiltrometer (TI) tests using numerical solution of the inverse problem based on the Richards equation. In almost all cases the wetting SWRCs were characterized by higher values of the pressure scaling parameter α compared to SWRCs measured in drainage experiments, which is consistent with the well-known phenomenon of hysteresis in soils. However, the BEST method resulted in significantly higher α and hydraulic conductivity Ks than TI, probably due to activation of the largest soil pores during ponded infiltration.

  • Wavelet transform analysis reveals differences between patients with impaired LVEF and healthy individuals
    • Marcin Gruszecki
    • Damian Kaufmann
    • Michał Świątczak
    • Krzysztof Młodziński
    • J Neary
    • Jyotpal Singh
    • Jacek Rumiński
    • Ludmiła Danilowicz-szymanowicz
    2024 Full text Kardiologia Polska

    Heart failure (HF) is a global pandemic. It af- fects 64 million people worldwide, with stead- ily increasing incidence, morbidity, mortality, and economic burden [1]. Forecasts indicate continued rising prevalence, especially among the elderly and in low-to-middle socio-de- mographic index regions [2]. Left ventricular ejection fraction (LVEF) significantly impacts HF treatment and prognosis [3]. The sequence of physiological changes related to reduced LVEF remains uncertain, and only limited re- search has explored these mechanisms. This study employed wavelet transformation (WT) to investigate oscillatory interactions, exploring aging and decreased LVEF effects on cardiovascular dynamics. We analyzed central (electrocardiogram [ECG]) and pe- ripheral (blood pressure [BP]) measurements, hypothesizing modified wavelet quantities in HF patients compared to healthy individuals.

  • Weakly Hydrated Solute of Mixed Hydrophobic–Hydrophilic Nature
    • Aneta Panuszko
    • Maciej Śmiechowski
    • Maciej Pieloszczyk
    • Adrian Malinowski
    • Janusz Stangret
    2024 JOURNAL OF PHYSICAL CHEMISTRY B

    Infrared (IR) spectroscopy is a commonly used and invaluable tool in studies of solvation phenomena in aqueous solutions. Concurrently, density functional theory calculations and ab initio molecular dynamics simulations deliver the solvation shell picture at the molecular detail level. The mentioned techniques allowed us to gain insights into the structure and energy of the hydrogen bonding network of water molecules around methylsulfonylmethane (MSM). In the hydration sphere of MSM, there are two types of populations of water molecules: a significant share of water molecules weakly bonded to the sulfone group and a smaller share of water molecules strongly bonded to each other around the methyl groups of MSM. The very weak hydrogen bond of water molecules with the hydrophilic group causes the extended network of water hydrogen bonds to be not "anchored" on the sulfone group, and consequently, the MSM hydration shell is labile.

  • Wet H2S corrosion and degradation of pipeline in amine regeneration system
    • Juliusz Orlikowski
    • Maciej Kalinowski
    • Igor Lasota
    • Piotr Maruszewski
    • Michał Szociński
    • Kazimierz Darowicki
    2024 MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION

    The paper presents the results of NDT examinations, metallographic tests and risk assessment of degradation related to corrosion of amine regeneration unit in a desulphurisation system. Intensive corrosion resulting from acid gases environment upon water condensation causes perforation of the pipeline. Detailed analysis reveals cracking related to the mechanism of wet H2S. Hydrogen penetration, resulting from the wet H2S process, causes a decrease in mechanical properties of steel and an increase in hydrogen content inside steel. Corrosion results mostly from high stream velocity, the presence of acid gases (with high ammonia content), the presence of amine and low stream temperature.

  • What drives sustainable investing? Adoption determinants of sustainable investing exchange-traded funds in Europe
    • Adam Marszk
    • Ewa Lechman
    2024 Structural Change and Economic Dynamics

    Despite the growing interest in various topics related to sustainable (ESG) investing, some issues remain understudied, such as the determinants of their utilization at the macro level. This paper contributes to the state of knowledge two-directionally. First, it shows the development of sustainable investing exchange-traded funds (ETFs) in European countries. Second, it traces the significant determinants of adopting sustainable investing/ESG ETFs in Europe. More specifically, we aim to determine which financial, technological, social or institutional factors have the most significant impact on the growth of levels and over-time dynamics of the sustainable investing ETFs. The empirical sample covers five European economies: France, Germany, Italy, Switzerland, and the United Kingdom and the period of the analysis is 2006-2020. Adopting panel regression analysis, we investigate twenty different variables that potentially impact the development of sustainable investing ETFs across examined countries. Our results confirm the positive effects of the development of insurance companies and pension funds for the assets of the ESG ETFs. Also, factors such as stock markets development, ICT adoption, financial access and literacy, and the prevalence of tertiary-level education demonstrate a positive impact on ESG ETFs. The role of the financial performance and tax levels resulted in being neutral, thus indicating the lesser importance of the financial motives in relation to the other factors. The results were mixed in the case of the mutual funds and institutional variables.

  • What is the future of digital education in the higher education sector? An overview of trends with example applications at Gdańsk Tech, Poland
    • Alina Guzik
    • Michał Tomczak
    • Małgorzata Gawrycka
    2024 Full text Global Journal of Engineering Education

    Universities worldwide recognise the need to adapt to changes in society, the economy and the way young people prefer to learn. Additionally, the impetus to improve the digital approach in higher education intensifies as educational institutions have to remain competitive with commercial providers of education. Following the latest technological trends and implementing strategies to develop new digital solutions helps to improve the teaching process and the quality of academic teaching. The purpose of this article is to identify, analyse and discuss digital education trends and development directions targeted at the higher education sector. The authors provide a comprehensive overview of the current situation and illustrate practical implementations through examples from Gdańsk University of Technology (Gdańsk Tech), Poland. These include e-learning, micro-credentials, extended reality (XR) technologies, gamification, digital textbooks and generative artificial intelligence (AI). Possible new directions of on-line digital education in the higher education sector development, as well as the benefits and associated risks, are also identified and discussed.

  • What makes them dream big? Determinants of business growth aspirations among Polish students
    • Jakub Golik
    2024 Entrepreneurial Business and Economics Review

    The objective of the article is to explore the concept of business growth aspirations and identify its determinants at an early stage of the entrepreneurial process. In this exploratory study, I focused on the underexplored approach to entrepreneurial process i.e. to study the growth aspirations and its determinants alongside entrepreneurial intentions. Studying growth aspirations and their determinants provides valuable insights into how these aspirations form. This contributes to the literature and future empirical studies on the entrepreneurial process. The results show that entrepreneurial self-efficacy and entrepreneurial intention proved to be statistically insignificant. Eventually, I found six of the variables to influence the declared growth aspirations of respondents in a statistically significant way, namely: gender, family business background, entrepreneurial role model, declared resistance to stress, and perception of higher income and prestige as the most attractive features of entrepreneurship. Moreover, I identified a gender gap in growth aspirations. Finally, I verified five out of eight proposed research hypotheses and discussed the conclusions. The most important finding shows the presence of a gender gap in growth aspirations as early as at the time of studies. Therefore, it is advised that policymakers focus on this gap while designing entrepreneurship courses and take it into account. Secondly, it is important to accurately measure stress resistance among students, to show it as a potential advantage, and to teach safe coping strategies. Furthermore, it is recommended to promote the high social status of entrepreneurs, both in the financial (potentially higher income) and non-financial sense (prestige and satisfaction) while at the same time consciously educating about potential dangers. The study makes an original contribution to the literature on growth aspirations by answering the call to further explore their potential antecedents and is one of the first to do so at the earliest stage of the entrepreneurial process. It is achieved by studying determinants pertaining to sociocultural and individual dimensions which – according to some studies – require further investigation. Moreover, it is done in an unexplored context of students in a developing country in Europe. Finally, the article recognises the ambiguity in defining growth aspirations and suggests a clear distinction to be included in the literature and future research.

  • When Does Automation in Government Thrive or Flounder?
    • Elsa Estevez
    • Tomasz Janowski
    • David Benjamin Roseth
    2024

    Government organizations worldwide are harvesting the transformative potential of digital technologies to automate interactions with citizens, businesses, and each other. Automation can bring benefits, such as an increase the efficiency of government operations, quality of government decisions, and convenience of government-citizen interactions. It can also produce adverse outcomes, such as compromising social value for economic gains, misjudging citizen circumstances, and having to compensate for the effects of algorithmic errors. This publication delves into the implications of automation and how to implement initiatives that increase its benefits and manage its risks. Specific questions include: (i) how to identify areas of public policy and public services that are most apt for automation; (ii) what questions, regarding potential benefits and costs, should governments ask before embarking on a process of automation; (iii) how governments should monitor the benefits and costs in the process of automation and establish whether automation has had the desired impact; and (iv) how to organize and manage automation efforts. The authors explore these issues through 12 case studies from 8 countries (Argentina, Chile, France, Norway, Paraguay, Singapore, Spain, Sweden), the European Union, and 7 government sectors (administration, border control, finance, justice, procurement, registry, and welfare). Each case study identifies the problem automation was designed to resolve or service it was designed to deliver; potential benefits and costs of automation that were relevant in each context; and examples of how automation was implemented to reduce costs and monitored to ensure high impact without unintended negative consequences. The cases guide the formulation of a taxonomy of benefits and risks of government automation initiatives and the four broad factors that government organizations should consider when aiming to realize the benefits and manage the risks of such initiatives: institutional readiness, human capacity, process innovation, and whole-of-government approach. It also presents strategies for implementing the factors and discusses how they help produce public value.

  • Why Are Left-Handed G-Quadruplexes Scarce?
    • Michał Jurkowski
    • Mateusz Kogut
    • Subrahmanyam Sappati
    • Jacek Czub
    2024 Full text Journal of Physical Chemistry Letters

    G-quadruplexes (G4s) are nucleic acid structures crucial for the regulation of gene expression and genome maintenance. While they hold promise as nanodevice components, achieving desired G4 folds requires understanding the interplay between stability and structural properties, like helicity. Although right-handed G4 structures dominate the experimental data, the molecular basis for this preference over left-handed helicity is unclear. To address this, we employ all-atom molecular dynamics simulations and quantum chemical methods. Our results reveal that right-handed G4s exhibit greater thermodynamic and kinetic stability as a result of favorable sugar–phosphate backbone conformations in guanine tracts. Moreover, while hydrogen-bonding patterns influence helicity-specific G4 loop conformations, they minimally affect stability differences. We also elucidate the strong correlation between helicity and the strand progression direction, essential for G4 structures. These findings deepen our understanding of G4s, providing molecular-level insights into their structural and energetic preferences, which could inform the design of novel nanodevices.

  • Why do Open Government Data initiatives fail in developing countries? A root cause analysis of the most prevalent barriers and problems
    • Charalampos Harris Alexopoulos
    • Stuti Saxena
    • Marijn Janssen
    • Nina Rizun
    • Martin Lnenicka
    • Ricardo Matheus
    2024 Full text Electronic Journal of Information Systems in Developing Countries

    Open government data (OGD) include the provision of government data, which have so far been reserved for the provision of public utilities and services, wherein different stakeholders may create value out of the same source. Recently, OGD initiatives around the world have dampened or were found to be inadequate for one or other reasons. The present study seeks to underline the root causes behind these inadequate or stalled initiatives with a specific focus on the developing countries. This article undertakes a literature review of the most significant studies in this area, followed by a root cause analysis wherein the database across Scopus and Web of Science has been explored with the set inclusion and exclusion criteria being set in line with the research focusing on the hinderances and bottlenecks behind the failure of OGD initiatives (n 15), thus not only summarizing what has been revealed in previous studies but also identifying these “root-cause” relationships, which are responsible for the stalled OGD projects. A deep understanding of the literature on OGD shows that research of OGD barriers repeat each other. The results show that the main root causes include politico-administrative, social, technological, legal and organizational (inter- and intra) dimensions including aspects like state of the economy, infrastructural issues, the tendency to copy the OGD initiative without need to institutionalize the same, and so forth. Whereas a number of studies are available covering the barriers in the roll-out and implementation of OGD initiatives, the root causes behind the existence of these barriers have not been identified so far-the present study seeks to plug this gap. Besides being a contribution to the extant OGD literature in general, the study seeks to leave academic and practical implications for furthering up deliberations and discussions on the OGD themes with specific impetus upon the cause analysis of the failure in OGD initiatives and the manner in which the same may be corrected or preempted

  • Wideband High-Gain Low-Profile Series-Fed Antenna Integrated with Optimized Metamaterials for 5G millimeter Wave Applications
    • Bashar Esmail
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Dustin Isleifson
    2024 Full text Scientific Reports

    This paper presents a series-fed four-dipole antenna with a broad bandwidth, high gain, and compact size for 5G millimeter wave (mm-wave) applications. The single dipole antenna provides a maximum gain of 6.2 dBi within its operational bandwidth, which ranges from 25.2 to 32.8 GHz. The proposed approach to enhance both gain and bandwidth involves a series-fed antenna design. It comprises four dipoles with varying lengths, and a truncated ground plane. These dipoles are connected in series on both sides, running in parallel through a microstrip line. The proposed design significantly enhances the bandwidth, which extends from 26.5 to 40 GHz. This frequency range effectively covers the 5G bands of 28 and 38 GHz. The expedited trust-region (TR) gradient-based search algorithm is utilized to optimize the dimensions of the antenna components, resulting in a maximum gain of 11.2 dBi at 38 GHz. To further enhance the gain, modified H-shaped metamaterial (MTM)-based unit cells are integrated into the antenna substrate. The TR algorithm is employed once more to optimize the MTM dimensions, yielding a maximum gain of 15.1 dBi at 38 GHz. The developed system is experimentally validated, showing excellent agreement between the simulated and measured data.

  • Wind Speed Probabilistic Forecast Based Wind Turbine Selection and Siting for Urban Environment
    • Piotr Doerffer
    • Shivangi Sachar
    • Shubham Shubham
    • Anton Ianakiev
    • Paweł Flaszyński
    2024 Full text IET Renewable Power Generation

    Wind energy being a free source of energy is becoming popular over the past decades and is being studied extensively. Integration of wind turbines is now being expanded to urban and offshore settings in contrast to the conventional wind farms in relatively open areas. The direct installation of wind turbines poses a potential risk, as it may result in financial losses in scenarios characterized by inadequate wind resource availability. Therefore, wind energy availability analysis in such urban environments is a necessity. This research paper presents an in-depth investigation conducted to predict the exploitable wind energy at four distinct locations within Nottingham, United Kingdom. Subsequently, the most suitable location, Clifton Campus at Nottingham Trent University, is identified where a comprehensive comparative analysis of power generation from eleven different wind turbine models is performed. The findings derived from this analysis suggest that the QR6 wind turbine emerges as the optimal choice for subsequent experimental investigations to be conducted in partnership with Nottingham Trent University. Furthermore, this study explores the selection of an appropriate probability density function for assessing wind potential considering seven different distributions namely, Gamma, Weibull, Rayleigh, Log-normal, Genextreme, Gumbel, and Normal. Ultimately, the Weibull probability distribution is selected, and various methodologies are employed to estimate its parameters, which are then ranked using statistical assessments.

  • Window frame integrable air recuperation minichannel/minigap heat exchanger
    • Paweł Dąbrowski
    • Rafał Andrzejczyk
    • Maciej Wacławik
    • Dariusz Mikielewicz
    2024 APPLIED THERMAL ENGINEERING

    This article describes an evaluation of mini heat exchangers operation as a decentralized mechanical ventilation system with recuperative heat recovery that can be integrated into the window frame. The relatively small yet efficient air recuperation system allows for retrofitting existing buildings by reducing the overall energy consumption and thus the CO2 emissions. The proposed design, unlike existing systems, is easy to scale up to various room sizes and is a promising solution for buildings where a centralized recuperation system cannot be implemented or interfering with the building’s facade is not allowed. The experimental research was carried out enabling to collect temperature, pressure drop, and volumetric flow rate measurements in a recuperation system with various minigeometries, namely minichannels with a hydraulic diameter of 3.00 mm, minigaps with a hydraulic diameter of 5.82 mm, and minigaps with a hydraulic diameter of 1.98 mm. The system was tested for a room air temperature of 22°C and three values of outside air temperatures, namely 5°C, 10°C, and 15°C. The volumetric flow rate for a single heat exchanger ranged from 4.1 m3/h to 20.4 m3/h. The results showed that higher temperature rise of supplied air and higher energy efficiency of the heat recovery can be achieved for smaller airflows and higher differences between outside and room temperatures. For an exemplary 34 m2 office room, the 0.8-fold air exchange rate can be provided and 1 667.1 kWh of annual energy savings can be achieved, corresponding to 50.3% of total energy required for heating the air. Heat exchangers equipped with 3.00 mm minichannels recover a similar amount of heat as the ones equipped with 5.82 mm minigaps, even though the hydraulic diameter of the minichannel is almost 2 times smaller. Meanwhile, a 5.82 mm minigap reduces the pressure drop by 76% compared to a 3.00 mm minichannel.

  • Wireless Charging Station Design for Electric Scooters: Case Study Analysis
    • Viktor Shevchenko
    • Oleksandr Husev
    • Dmitri Vinnikov
    • Ryszard Strzelecki
    • Bohdan Pakhaliuk
    2024 Full text ENERGIES

    This study proposes an example of a wireless charging station design for a small-scale vehicle available on the market. The article analyzes basic transmitter inverter topologies and their compensation methods in terms of flexibility of control, tolerance to uncertainty in positioning, and the possibility of decreasing the integration price. Our comprehensive analysis focuses on the battery voltage range, energy capacity, cost, and travel distance. We evaluate the constraints of efficiency, transmitted power, amount of used material, and size of the energy delivery system based on our design example. The aim is to increase the penetration of wireless technology in terms of convenience and integration capabilities.

  • Wirtualny pokój zagadek z zakresu matematyki
    • Radosław Baziak
    • Tomasz Daruk
    • Karol Żyra
    • Dorota Żarek
    • Jacek Lebiedź
    2024 Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    W artykule przedstawiono realizację pokoju z zagadkami matematycznymi opartego na rzeczywistości wirtualnej. Celem było stworzenie wciągającej gry z zakresu matematyki, w którą aktywnie angażują się studenci. Zespół badawczy zbudował aplikację do wykorzystania w Laboratorium Zanurzonej Wizualizacji Przestrzennej na Politechnice Gdańskiej. Gra składa się z czterech pokojów: pokoju wprowadzającego i trzech pokojów tematycznych. Łącznie w pokojach znajduje się 13 zagadek wymagających matematycznego myślenia. W celu oceny walorów edukacyjnych narzędzia, przygotowano ankiety i przeprowadzono eksperyment ze studentami pierwszego i trzeciego roku studiów. W artykule autorzy omówili zastosowanie rzeczywistości wirtualnej i koncepcji pokoju zagadek (ang. escape room) w celu stworzenia innowacyjnego narzędzia angażującego studentów w proces nauki matematyki w interaktywnej, stymulującej wizualnie scenografii.

  • Właściwości i potencjalne zastosowania azobenzokoron: hydroksyazobenzokorony
    • Paulina Szulc
    2024 Full text

    W rozprawie doktorskiej przedstawiono właściwości oraz metody syntezy azobenzokoron oraz hydroksyazobenzokoron. Opisano również zastosowanie związków makrocyklicznych jako chromojonoforów w czujnikach optycznych. W ramach pracy zbadano wpływ pH, rozpuszczalników oraz obecności jonów na równowagę tautomeryczną wybranych hydroksyazobenzokoron. Zbadano również równowagę kompleksowania jonów metali przez te związki oraz sprawdzono ich użyteczność jako materiał sensorowy. Przeprowadzone badania pozwoliły stwierdzić, że 19-członowa para-hydroksyazobenzokorona z dwoma podstawnikami fenylowymi kompleksuje m.in. jony glinu. Badania nad optodami na bazie porowatego szkła modyfikowanego polistyrenem z zastosowaniem tego związku jako chromojonoforu potwierdziły ich czułość na obecność tych jonów w roztworze wodnym. Po raz pierwszy scharakteryzowano także właściwości fluorescencyjne para hydroksyazobenzokoron. Wyznaczono wartości wydajności kwantowych oraz wartości stałej Sterna Volmera dla szeregu tych związków oraz określono zależność między strukturą a właściwościami fluorescencyjnymi. Opisano również nową metodę otrzymywania azobenzokoron z wykorzystaniem tlenku manganu(IV) jako utleniacza. Określono najbardziej optymalne warunku tego typu reakcji i otrzymano na tej drodze nowy związek: 19-członową azobenzokoronę z dwoma podstawnikami tert-oktylowymi.

  • Wpływ dawkowania pasty ściernej na intensywność docierania próbek płaskich
    • Adam Barylski
    • Patrycja Janczurewicz
    2024 Inżynieria Materiałowa

    Przedstawiono wyniki badań intensywności docierania próbek płaskich ze stopu aluminium, brązu aluminiowego i żeliwa sferoidalnego na docierarce jednotarczowej. Analizowano wpływ okresowego dawkowania elektrokorundowej pasty ściernej na wydajność obróbki w funkcji czasu, w zależności od położenia próbek w separatorach oraz liczby próbek docieranych jednocześnie i wywieranego nacisku jednostkowego.

  • Wpływ parametrów strugi paliwa wtryskiwanego do cylindra silnika okrętowego na początkową fazę rozpylania
    • Joanna Grochowalska
    2024 Full text

    Przedmiotem rozprawy jest analiza procesu wtrysku oleju napędowego do cylindra silnika okrętowego z zapłonem samoczynnym i bezpośrednim wtryskiem paliwa. Analiza tego zagadnienia została przeprowadzona w aspekcie wpływu makro parametrów strugi na początkową fazę rozpylania oleju napędowego. Celem niniejszej pracy jest określenie wpływu współczynnika L/D (długość otworu/średnica) otworu wylotowego wtryskiwacza na zmianę charakterystyki zasięgu strugi oraz kąta stożka strugi w czasie w początkowej fazie rozpylania. W tym celu przeprowadzono badania eksperymentalne, podczas których olej napędowy wtryskiwano do komory o stałej objętości pod różnym ciśnieniem. Metodę optyczną techniką Mie scattering wykorzystano do wizualizacji propagacji wtryskiwanego paliwa. Wyniki badań pokazały, że L/D otworu wylotowego, ciśnienie wtryskiwanego paliwa i przeciwciśnienie w komorze wpływają na makro parametry strugi w początkowej fazie rozpylania. Na podstawie wyników badań eksperymentalnych zostały zbudowane modele matematyczne pozwalające na obliczenie makro parametrów strugi rozpylanego oleju napędowego zmiennych w czasie w początkowej fazie rozpylania. Zbudowane modele poddano ocenie oraz weryfikacji oryginalnymi wynikami badań eksperymentalnych.

  • Wpływ popiołu lotnego na wybrane cechy mechaniczne gruntów organicznych
    • Witold Tisler
    • Dominik Maciejewski
    • Paweł Markowski
    • Mateusz Michalski
    • Marta Moroz
    2024 Builder

    Wzmacnianie gruntów polega na poprawie ich właściwości poprzez dodawanie innych materiałów lub spoiw. Obecnie stosuje się głównie wapno palone i cement, które są skuteczne, ale drogie i nieekologiczne. Produkcja cementu emituje znaczne ilości CO2, dlatego poszukuje się alternatywy, którą może być popiół lotny. W niniejszej pracy do badań wykorzystano popiół lotny klasy F (wg ASTM) i sprawdzono czy mimo mniejszej zawartości tlenku wapnia jest w stanie być alternatywą dla cementu czy wapna. Przeprowadzono serię badań polegających na wymieszaniu gruntu organicznego (namuł) z cementem oraz popiołem, a następnie zbadano wytrzymałość jednoosiową po 7 oraz 28 dniach. Uzyskane wyniki pokazują, że popiół może być alternatywą dla cementu. Kluczowy jest jednak okres dojrzewania oraz powstanie reakcji pucolanowych, których efektem jest wzrost wytrzymałości gruntu.

  • WPŁYW SKŁADU ANODY NA WYDAJNOŚĆ I STABILNOŚĆ TLENKOWYCH OGNIW PALIWOWYCH NIO+YSZ/YSZ/LACOFEO3-Δ
    • Aleksander Mroziński
    • Krzysztof Szostak
    • Jan Kulawik
    • Sebastian Molin
    • Dagmara Uhl
    • Piotr Jasiński
    • Beata Synkiewicz-musialska
    2024 Full text Elektronika : konstrukcje, technologie, zastosowania

    Badano wpływ proporcji składników anody na mikrostrukturę, widma impedancyjne i charakterystyki prądowo napięciowe testowych ogniw paliwowych z elektrolitem stałym na bazie tlenku cyrkonu stabilizowanego tlenkiem itru (YSZ), anodą NiO+YSZ i katodą LaCoFeO3-δ. Pomiary przeprowadzono dla różnej zawartości pary wodnej, ciśnienia parcjalnego wodoru, a także po starzeniu pod obciążeniem 300 mA/cm2. Najlepszą wydajność i stabilność uzyskano dla ogniw ze zwiększoną ilością grafitu w wyjściowym składzie materiału anodowego.

  • Wpływ stosowanych praktyk rolniczych na dopływ wód podziemnych oraz azotanów do Zatoki Puckiej
    • Dawid Potrykus
    2024 Full text Przegląd Geologiczny

    Eutrophication of marine basins associated with submarine groundwater discharge is currently one of the most important challenges in modern coastal hydrogeology, and is classified as a serious global environmental problem. A particular source of groundwater pollution is agricultural activity, which is commonly carried out in the coastal zone. Research was conducted on a representative part of the Bay of Puck watershed, dominated by agricultural land use. The geological setting of the study area is heterogeneous, which has a significant influence on groundwater flow and occurrence in the multi-aquifer hydrosystem, draining into Puck Bay. The impact of agricultural practices on groundwater and nitrate discharge to the Puck Bay was determined, by an integrated modeling approach, developed using combination of the SWAT, MODFLOW-NWT and MT3DMS codes. Spatial and seasonal variations of the N-NO3 load leached from the soil profile and the infiltration of precipitation are convergent with observed trends in the discharge of groundwater and N-NO3 loads into Puck Bay. The simulations show that 1,355.13 m3/h of groundwater and 1.87 kg/h (16.4 t/year) of N-NO3 load are discharged into Puck Bay from the aquifers analyzed, the majority of which comes from an upper aquifer. The distribution of the values as determined was found to be influenced by agricultural practices, resulting from changes in crop structure, fertilizer management, cultivation methods and grazing.

  • Wpływ widma promieniowania optycznego i położenia oprawy oświetleniowej wykorzystującej źródła elektroluminescencyjne na efektywność i minimalizację zużycia energii elektrycznej w farmie wertykalnej
    • Mateusz Feldzensztajn
    2024 Full text

    Rozprawa poświęcona jest optymalizacji modułów oświetlenia upraw roślinnych. W rozprawie wzięto pod uwagę zarówno wpływ widma światła modułów oświetlenia na własności użytkowe roślin, jak również aspektów energetycznych (oszczędność energii elektrycznej) oraz ogólnej sprawności modułów oświetlenia. W rozprawie udowodniono, że zindywidualizowany dobór widma promieniowania optycznego oprawy oświetleniowej stosowanej do uprawy roślin pozwala na poprawę własności użytecznych i wizualnych zbiorów wybranych gatunków roślin. Wśród tych właściwości można wyróżnić wzrost masy, lepsze wybarwienie, zwiększenie zawartości chlorofilu, zwiększenie ilości antocyjanów, poprawa ogólnej kondycji roślin. Wykazano również, że optymalizacja konstrukcji oraz odpowiedni dobór diod LED i sposobu montażu oprawy oświetleniowej pozwala na oszczędności energii elektrycznej oraz redukcji kosztów w oświetlaniu upraw roślin. W ramach pracy opracowano trzy stanowiska doświadczalne wyposażone w moduły oświetleniowe oraz przeprowadzono uprawy doświadczalne w formie farmy wertykalnej. Podsumowanie pracy zawiera wnioski ogólne, oryginalne osiągnięcia autora oraz prezentuje kierunki rozwoju prowadzonych badań.

  • Wpływ wysokiej osteotomii piszczelowej na mechanikę stawu kolanowego
    • Sebastian Grelik-Urbanowski
    2024 Full text

    W rozprawie podjęto próbę weryfikacji wpływu zabiegu chirurgicznego wysokiej osteotomii piszczelowej na mechanikę stawu kolanowego. Po wykonanym przeglądzie literatury, postawiono trzy hipotezy, które poddano weryfikacji na drodze badań numerycznych. Otrzymane wyniki zwalidowano poprzez badania nacisków powierzchniowych występujących w stawach kolanowych świni domowej, prowadzonych na maszynie do jednoosiowego ściskania. Praca posiada również cel utylitarny, jakim jest wyznaczenie nowej metody określania kąta korekcji w zabiegu wysokiej osteotomii piszczelowej. Pierwsza hipoteza dotyczy wpływu odmiennych wartości modułów Younga tkanki kostnej i materiału płyty stabilizującej na otrzymaną korekcję. Badania numeryczne wykazały, że wpływ wynosi 0,08o. Uzyskana wartość jest klinicznie nieznacząca. Druga hipoteza dotyczy przywrócenia fizjologicznych nacisków powierzchniowych na powierzchniach stawowych po zabiegu. Analizy wykazały brak przywrócenia fizjologicznych nacisków powierzchniowych. Trzecia hipoteza dotyczy przywrócenia anatomicznego położenia łąkotek po zabiegu. Badania numeryczne wykazały, że zabieg nie przywraca anatomicznego położenia łąkotek. Badania walidacyjne potwierdziły wyniki otrzymane w analizach numerycznych. Cel utylitarny został spełniony, a nowa metoda wyznaczania kąta korekcji zbliżyła wartości i rozkład nacisków w stawie po zabiegu, do stanu w stawie zdrowym.

  • Wpływ zawartości grafitu na właściwości mechaniczne warstw hybrydowych Ni-P/Si3N4/grafit osadzonych na stopie AW-7075 metodą redukcji chemicznej.
    • Kazimierz Czapczyk
    2024 Full text Przemysł Chemiczny

    Przedstawiono wpływ obecności grafitu jako fazy dyspersyjnej na właściwości mechaniczne warstw hybrydowych Ni-P/Si3N4/grafit, które osadzono metodą redukcji chemicznej na stopie glinu AW-7075. Wykonano badania morfologii powierzchni warstw metodą mikroskopii świetlnej i skaningowej. Dalszą część pracy stanowiły badania mechaniczne, czyli pomiary mikrotwardości warstw oraz ich adhezji do aluminiowego podłoża, a także analizy wpływu obecności grafitu na podstawowe właściwości materiału powłokowego. Zbadano próbki ze stopu AW-7075, na których osadzono metodą bezprądową powłoki hybrydowe i porównawczo nanokompozytowe o różnym składzie chemicznym, modyfikowanym zawartością faz dyspersyjnych.

  • Wybrane teoretyczne i aplikacyjne własności Msplit estymacji
    • Marek Zienkiewicz
    2024

    Praca składa się z siedmiu rozdziałów. Rozdział pierwszy jest poświęcony M-estymacji traktowanej jako uogólnienie MNW. Szczególną uwagę zwrócono w nim na odporną klasę M-estymatorów stanowiącą bazę porównawczą w analizie odporności Msplit estymatorów. W rozdziale drugim przedstawiono teoretyczne podstawy Msplit estymacji oraz jej rozwinięć i przypadków szczególnych (kwadratowej Msplit estymacji, Shift-Msplit estymacji i Msplit (q) estymacji). Zwrócono uwagę na podobieństwa i różnice pomiędzy tą metodą a klasyczną M-estymacją. Kwadratową Msplit estymację uzupełniono statystycznym modelem obserwacji zawierającym wspólną dla rozszczepionych modeli macierz kofaktorów (lub wag) i rozszczepione nieznane współczynniki wariancji. Zasadniczą część monografii stanowią jej pozostałe rozdziały, które obok części teoretycznych zawierają także analizy o charakterze empiryczno-numerycznym. W rozdziale trzecim zaproponowano sposób oceny dokładności kwadratowych Msplit estymatorów oraz konkurencyjnych poprawek i wyrównanych obserwacji wyznaczanych na ich podstawie. Przedstawiono macierze kowariancji tych wielkości i ustalono estymatory rozszczepionych współczynników wariancji. Rozdział czwarty zawiera opis oraz analizę Msplit i Shift- Msplit estymacji uzupełnionych o wirtualne modele funkcjonalne absorbujące „nietypowe” obserwacje. Koncepcja takiego uzupełnienia, dającego szczególny typ odporności Msplit i Shift- Msplit estymatorom, została już wcześniej opublikowana przez autora niniejszej pracy. W ramach uzupełnienia zawartych tam wyników tutaj przeprowadzono dodatkowe testy o charakterze empirycznym. W rozdziale piątym analizie numerycznej (z zastosowaniem metody Monte Carlo) poddano własności Msplit estymacji w kontekście odporności na błędy grube i w porównaniu z odpornymi M-estymatorami. Treść rozdziału szóstego stanowi uogólnienie kwadratowej Msplit estymacji na przypadek zmiennych zależnych. Rozdział siódmy zawiera podsumowanie i wnioski. Pracę kończy zestawienie piśmiennictwa.

  • Wybrane zagadnienia obliczeniowe w procesie projektowania kolejowego mostu łukowego z wieszakami w układzie siatkowym
    • Przemysław Kalitowski
    • Krzysztof Żółtowski
    • Nikodem Górski
    • Mariusz Łucki
    • Michał Stalmirski
    2024 Mosty

    Artykuł omawia proces projektowania mostu łukowego nad rzeką Dunajec w ramach modernizacji linii kolejowej nr 104 Chabówka – Nowy Sącz. Autorzy przedstawiają szczegółowe analizy koncepcyjne i statyczno-wytrzymałościowe, które doprowadziły do wyboru konstrukcji łukowej z siatkowym układem wieszaków (network arch) zamiast kratownicy. Decyzja ta umożliwiła optymalizację zużycia materiałów oraz zwiększenie walorów estetycznych mostu. Przeprowadzono kompleksowe analizy MES dotyczące nośności, rozkładu wieszaków, stateczności łuku i dynamiki przęsła, które pozwoliły na spełnienie normowych wymagań dotyczących mostów kolejowych. Ostateczny projekt przewiduje sprężony pomost betonowy, który zapewnia większą sztywność poprzeczną. Po przeprowadzeniu zaawansowanych analiz dynamicznych, stwierdzono brak efektów rezonansu między przęsłem a wieszakami, co gwarantuje bezpieczeństwo i komfort użytkowania konstrukcji. Projekt mostu jest obecnie realizowany, a jego oddanie do użytku planowane jest na 2025 rok.

  • Wykorzystanie pomiarów wyładowań niezupełnych do oceny układu izolacyjnego izolatora przepustowego średniego napięcia do zastosowań technologicznych
    • Paweł Pankowski
    • Marek Olesz
    • Sayed Mohammad Kameli
    2024 Full text Przegląd Elektrotechniczny

    W artykule przedstawiono wyniki badań wyładowań niezupełnych (wnz) w układzie izolacyjnym eksploatowanego izolatora przepustowego średniego napięcia (SN) mierzonych bezpośrednią metodą elektryczną i innymi technikami pomiarowymi wykorzystującymi czujniki pojemnościowe, indukcyjne, elektromagnetyczne oraz metodą chemiczną. Wykorzystane metody pomiarowe umożliwiają nie tylko detekcję wyładowań niezupełnych, ale również umożliwiają wnioskowanie dotyczące rodzaju wady i zaawansowania procesu starzenia układu izolacyjnego. Badania izolatora przepustowego wykonano przy różnych napięciach, aby określić, czy przy napięciu znamionowym pracy będzie możliwe wykrycie typowych wnz rozwijających się podczas eksploatacyjnego starzenia. Dodatkowo przeprowadzone badania pozwoliły zweryfikować hipotezy badawcze wynikające z symulacji komputerowych układu izolacyjnego przepustu.

  • Wykorzystanie rachunku niecałkowitego rzędu w sterowaniu suwnicą 3D
    • Michał Kędziora
    • Krzysztof Leszczyński
    • Robert Piotrowski
    2024 Full text Pomiary Automatyka Robotyka

    Suwnica 3D jest obiektem stosowanym w różnych gałęziach przemysłu. Z punktu widzenia sterowania, jest to system dynamiczny, nieliniowy i wielowymiarowy. W artykule zaprojektowano dwa układy regulacji: z klasycznym regulatorem PID oraz z regulatorem PID ułamkowego rzędu. Przedstawiono analizę porównawczą zaprojektowanych układów regulacji.

  • Wypalenie zawodowe: czy potrzebne jest leczenie?
    • Beata Basińska
    2024 Psychiatria po Dyplomie

    Professional burnout syndrome is an indicator of a process of health deterioration related to work. According to the Job Demands-Resources Theory, professional burnout develops in the workplace as a result of excessive job demands that are not balanced by personal and organizational resources. Professional burnout can affect employees across various sectors and organizations. The World Health Organization defines burnout as a syndrome caused by chronic workplace stress that has not been successfully managed. It is characterized by feelings of energy depletion, increased mental distance from one’s job, and reduced professional efficacy. According to the latest research, the main components of burnout are exhaustion, distancing from work, and impaired cognitive and emotional functioning. These core symptoms may be accompanied by secondary symptoms, such as low mood or nonspecific signs of distress. Professional burnout shares common variance with other mental health problems, particularly anxiety and depression, yet they are not identical phenomena. Furthermore, research on the prevalence of burnout among employees should include individuals seeking psychological and medical help. Burnout impacts both professional and personal quality of life. Consequently, preventive measures addressing burnout are increasingly seen as a domain of organizational improvement, while interventions and treatments for mental health issues remain the domain of medical professionals.

  • wystawa pokonkursowa Ogólnopolskiego Konkursu Prototypów Koncepcji Kreatorskich ‘NIE_MATERIA
    • Agnieszka Kurkowska
    • Anna Wróblewska
    2024

    Prezentacja przedstawiana na wystawie składa się z cyklu akwareli, rysunków koncepcyjnych, schematów na kartach prezentacyjnych z opisem koncepcji oraz dwóch plansz z esejem referującym projekt i obrazu na płótnie wykonanego akrylem.

  • Wystawa VI Ogólnopolskiego Konkursu Malarskiego im. Leona Wyczółkowskiego w Bydgoszczy
    • Łukasz Ławrynowicz
    2024

    I Ogólnopolski Konkurs Malarski im. Leona Wyczółkowskiego w Bydgoszczy to kolejna edycja wydarzenia w formule biennale, którego celem jest prezentacja, konfrontacja oraz gratyfikacja najlepszych reprezentantów współczesnego malarstwa z całej Polski. Konkurs ma formę otwartą, skierowaną zarówno do artystów debiutujących, jak i mogących poszczycić się bogatym i uznanym dorobkiem artystycznym.