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Gdańsk University of Technology

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  • Ultra-Wideband Vivaldi Antenna with an Integrated Noise-Rejecting Parasitic Notch Filter for Online Partial Discharge Detection
    • Sayed Mohammad Kameli
    • Shady S. Refaat
    • Haitham Abu-Rub
    • Ahmad Darwish
    • Ali Ghrayeb
    • Marek Olesz
    2024 IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT

    Power transformers and gas-insulated switchgear (GIS) play crucial roles in electrical power grids. However, they may suffer from degradation of insulation material due to wear and tear, leading to their imminent failure. Partial discharges (PDs) are an initial sign of insulation materials degradation which emit signals spanning various physical domains, including electromagnetic. PDs are temporally narrow, high-frequency, stochastic radiation sources. The Ultra-Wideband Vivaldi Antenna is the key element for the detection of PDs in power transformers and gas-insulated switchgear. However, they may be subject to different interference environments due to external sources of telecommunication radiation noise occupying the 2.4 GHz – 2.5 GHz band. Noise mixing with PD signals is challenging to resolve, especially for external sensors. Wi-Fi and Bluetooth signals from mobile devices easily overshadow faint PD signals. Band-reject frequency filters may be attached to the antenna, often at the detriment of the insertion loss. The integrated filter does not require any additional post-processing, making it less computationally demanding for smaller processors used in practice. Wi-Fi and Bluetooth degrade the PD signal, necessitating an integrated analog notch filter for noise removal. Therefore, an external ultra-wideband (UWB) Vivaldi antenna with an integrated noise-rejecting parasitic notch filter is designed, fabricated, and tested to detect PDs in electrical assets such as transformers, power cables, and GIS, with GIS being the focus in the experimental validation in this study. A comparative study of the proposed antenna is presented. This paper proposed an antenna that is designed to provide coverage of 95.516% of the 0.226 GHz – 3.506 GHz frequency band, with an average return loss of -16.04 dB and a peak gain of 5.5 in the working band, excluding the notched band. The peak return loss in the 2.4 GHz – 2.5 GHz rejection band is -2.68 dB, with an average attenuation of -35.74 dB. This wide coverage is demonstrated in this paper using simulation and experimentally.

  • Understanding the Dominant Physics Mechanisms on the p-i-n Perovskite Solar Cells Fabricated by Scalable Slot-Die Coating Process in Ambient Air
    • Damian Głowienka
    • Shih-Han Huang
    • Pei-Huan Lee
    • Feng-Yu Tsai
    • Wei-Fang Su
    2024 Full text Solar RRL

    Perovskite solar cells (PSC) are emerging technologies that have shown continuous improvement in power conversion efficiency (PCE) and stability. However, a very important aspect that has been seldom considered is the reproducibility of PCE of PSC devices. It is possible to achieve PCE from 10.21% to 17.05% using scalable slot-die-coating technique. However, a spatial distribution of performance is clearly observed for device samples on a 4 × 4 cm substrate. The relatively low PCE is mainly coming from the losses of electrical mechanism. To have in-depth understanding of the losses, the dominant loss analysis techniques including numerical simulations are used to explore the mechanism. In the results, it is indicated that a part of efficiency decrease is due to the increase of bulk defect density which linearly changes with the quality of the perovskite layer and related to recombination process. However, extremely high-charge-carrier transportation losses are found at the HTL/perovskite interface that are related to the Fermi-level pinning mechanism for low-efficiency device. The result of physics insight of perovskite solar cells leads to a strategy, where chemical passivation technique is used to achieve the PCE from 13.81% to 18.07% for the batch of devices with good reproducibility.

  • Understanding the Ukrainian Migrants Challenges in the EU: A Topic Modeling Approach
    • Nina Khairova
    • Nina Rizun
    • Charalampos Harris Alexopoulos
    • Magdalena Ciesielska
    • Arsenii Lukashevskyi
    • Ivan Redozub
    2024 Full text

    Confronted with the aggression against Ukraine in 2022, Europe faces one of the most important humanitarian challenges - the migration of war refugees from Ukraine, most of them women with children and the elderly. Both international institutions such as the European Union and the United Nations, but also national governments and, above all, local governments, which are the main providers of services and resources for refugees, are taking a number of measures to meet the needs. The extraordinary nature and extensive humanitarian needs pose exceptional challenges for both governments and Non-Governmental Organizations (NGOs) as well as civil society. The European countries adopted distinct reception procedures to accommodate war refugees in their territories. The purpose of this paper is to examine the challenges of war refugees from Ukraine and gain an understanding of how they vary across selected European countries. Using a text analytics approach such as BERTopic topic modeling, we analyzed text messages published on Telegram channels from February 2022 to September 2023, revealing 12 challenges facing Ukrainian migrants. Furthermore, our study delves into these challenges distribution across 6 major European countries with significant migrant populations, providing insights into regional differences. Additionally, temporal changes in 8 narrative themes in discussions of Ukrainian migration, extracted from official government websites, were examined. Together, this research contributes (1) to demonstrating how analytics-driven methodology can potentially be used to extract in-depth knowledge from textual data freely available on social media; and (2) to a deeper understanding of the various issues affecting the adaptation of Ukrainian migrants in European countries. The study also provides recommendations to improve programs and policies to better support the successful integration of Ukrainian migrants in host countries

  • Underwater Electrochemical Offshore Tests of a Paint Coating Applied in Water on the Legs of an Oil Production Platform
    • Juliusz Orlikowski
    • Krzysztof Żakowski
    • Michał Szociński
    • Piotr Igliński
    • Agata Jazdzewska
    • Łukasz Gaweł
    2024 Materials

    This paper presents the methodology developed for underwater measurements using electrochemical impedance spectroscopy (EIS) technique, aimed at determining the resistance of an epoxy coating applied in seawater to the legs of an oil production platform. Performing such underwater tests in an offshore environment was technically challenging. The results of measurements obtained on the platform were confronted with comparative results obtained in the laboratory, where the properties of the coating applied in water collected from the Baltic Sea (thickness, hardness, adhesion, and electrical resistance) were examined. This made it possible to conclude about the correctness of the paint coating application by divers on the legs of the platform. The single-layer epoxy coating applied by brush to the platform legs had a resistance above 10 kΩ·cm2 and thus met the assumed minimum resistance of the protective coating cooperating with cathodic protection as the anti-corrosion protection system of the platform legs. The synergy of these two technologies ensures full protection of offshore structures against corrosion. Measurements of the potential of the platform legs confirmed this. Before painting, the potential value at a depth of 0–15 m was 310 ÷ 320 mV versus the zinc reference electrode, while after painting the potential value decreased to 220 ÷ 240 mV, which means that the effect of full cathodic protection was achieved and the platform legs were protected from corrosion. The developed methodology for underwater EIS measurements on the high seas can be applied to any underwater metal structure to assess the quality of protective coatings.

  • Unequally-Spaced Slot Strategy for Radiation Null Reduction in Single SIW-Embedded Antenna Element
    • Meha Agrawal
    • Ravi Yadav
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2024 Full text Scientific Reports

    The incorporation of higher-order modes (HOMs) can substantially augment the antenna gain and bandwidth, but this improvement is typically accompanied by compromised radiation performance including radiation nulls and higher side lobe levels. In this study, an inventive strategy is introduced to reduce the radiation nulls and the side lobe levels of a single antenna element by positioning multiple slots of the radiating element at unequal spacing. Dual hybrid HOMs are analyzed inside a Substrate Integrated Waveguide (SIW)-based cavity to design a wide band, enhanced gain dual-polarized antenna. The radiating element of the antenna is designed with multiple slots positioned at unequal spacing but symmetrical along the origin. This methodology provides three-fold advantages: a reduction of side lobes, an adjustment of phase center, and a significant reduction of radiation nulls. The antenna has been fabricated, and experimentally validated. The antenna exhibits a reduction in radiation null to –0.5 dB, a phase adjustment of the main lobe to 0°, and a reduction in side lobe level from -14.4 dB (N = 2, equal spacing) and –15.5 dB (N = 4, equal spacing) a maximum of -19.7 dB (N = 4, unequal spacing) at 12.35 GHz in the phi-0 plane. Excellent agreement between measured and simulated results corroborates the efficacy of the proposed approach. The significant improvement in the radiation performance of the single-element antenna design sets the antenna design apart from the state-of-the-art solutions.

  • Uniwersalne uchwyty obróbkowe wykorzystujące siły magnetyczne
    • Adam Barylski
    2024 Projektowanie i Konstrukcje Inżynierskie

    Przedstawiono współczesne konstrukcje uniwersalnych uchwytów przedmiotowych wykorzystujące do zamocowania przedmiotów obrabianych siły magnetyczne. Analizowano uchwyty magnetyczne i elektromagnetyczne w technologia obróbki wiórowej i ściernej oraz w technikach spawalniczych.

  • Unraveling the role of boron dimers in the electrical anisotropy and superconductivity in boron-doped diamond
    • Michał Sobaszek
    • Soonho Kwon
    • Tomasz Klimczuk
    • Paweł P. Michałowski
    • Jacek Ryl
    • Bogdan Rutkowski
    • Dongying Wang
    • Xinwei Li
    • Marc Bockrath
    • Robert Bogdanowicz
    • William A. Goddard III
    2024 CARBON

    We use quantum mechanics (QM) to determine the states formed by B dopants in diamond. We find that isolated B sites prefer to form BB dimers and that the dimers pair up to form tetramers (BBCBB) that prefer to aggregate parallel to the (111) surface in the <110> direction, one double layer below the H-terminated surface double layer. These tetramers lead to metallic character (Mott metal Insulator Transition) with holes in the valence band near the point and electrons in the BBCBB tetramer promoted band along the X direction. Our experiments find very significant anisotropy in the superconductivity for boron-doped diamond thin films prepared with Microwave Plasma Assisted Chemical Vapor Deposition using deuterium-rich plasma. This leads to much higher conductivity in the X direction than the Y direction, as predicted by the QM. This phase transition to the anomalous phase is linked with the emergence of boson quantum entanglement states behaving as a bosonic insulating state. These anisotropic superconducting properties of the diamond film might enable applications such as single-photon detectors. We expect that this formation of a dirty superconductivity state is related to the BBCBB tetramers found in our QM calculations.

  • Unsupervised Learning for Biomechanical Data Using Self-organising Maps, an Approach for Temporomandibular Joint Analysis
    • Mateusz Troka
    • Wiktoria Wojnicz
    • Katarzyna Szepietowska
    • Izabela Lubowiecka
    2024

    We proposed to apply a specific machine learning technique called Self-Organising Maps (SOM) to identify similarities in the performance of muscles around human temporomandibular joint (TMJ). The performance was assessed by measuring muscle activation with the use of surface electromyography (sEMG). SOM algorithm used in the study was able to find clusters of data in sEMG test results. The SOM analysis was based on processed sEMG data collected when testing subjects performing four mandibular motions: opening, closing, protrusion and retrusion. Muscle activation of four TMJ muscles (masseter right, masseter left, temporalis right and temporalis left) were used as input variables for SOM algorithm. The results of the network are presented on U-matrix maps. These maps consist of formed groupings that correspond to similarities in data points that clustered together. The clustering implies similarity in muscle activation of different subjects. The results show that it is possible to cluster medical datasets with SOM algorithm in the analysis of full jaw motions, which may support the diagnostic process.

  • Unusual dynamics and nonlinear thermal self-focusing of initially focused magnetoacoustic beams in a plasma
    • Anna Perelomova
    2024 Full text CONTRIBUTIONS TO PLASMA PHYSICS

    Unusual thermal self-focusing of two-dimensional beams in plasma which axis is parallel to the equilibrium straight magnetic field is considered. The equi- librium parameters of plasma determine scenario of a beam divergence (usual or unusual) which is stronger as compared with a flow without magnetic field. Nonlinear thermal self-action of a magnetosonic beam behaves differently in the ordinary and unusual cases. Damping of wave perturbations and normal defocusing in gases leads to reduction of the magnitude of initially planar per- turbations at the axis of a beam. Additional thermal self-focusing nonspecific for gases occurs in plasma under some condition which counteracts this reduc- tion. The theory and numerical examples concern thermal self-action of initially focused (defocused) magnetosonic beam. Dynamics of perturbations in a beam is determined by dimensionless parameters responsible for diffraction, damp- ing of the wave perturbations, initial radius of a beam’s front curvature, and the ratio of viscous to thermal damping coefficients.

  • Unveiling the electron-induced ionization cross sections and fragmentation mechanisms of 3,4-dihydro-2H-pyran
    • Tomasz Wąsowicz
    • Michał Jurkowski
    • Allison Harris
    • Ivan Ljubić
    2024 Full text JOURNAL OF CHEMICAL PHYSICS

    The interactions of electrons with molecular systems under various conditions are essential to interdisciplinary research fields extending over the fundamental and applied sciences. In particular, investigating electron-induced ionization and dissociation of molecules may shed light on the radiation damage to living cells, the physicochemical processes in interstellar environments, and reaction mechanisms occurring in combustion or plasma. We have, therefore, studied electron-induced ionization and dissociation of the gas phase 3,4-dihydro-2H-pyran (DHP), a cyclic ether appearing to be a viable moiety for developing efficient clinical pharmacokinetics and revealing the mechanisms of biofuel combustion. The mass spectra in the m/z = 10–90 mass range were measured at several different energies of the ionizing electron beam using mass spectrometry. The mass spectra of DHP at the same energies were simulated using on-the-fly semi-classical molecular dynamics (MD) within the framework of the QCxMS formalism. The MD settings were suitably adjusted until a good agreement with the experimental mass spectra intensities was achieved, thus enabling a reliable assignment of cations and unraveling the plausible fragmentation channels. Based on the measurement of the absolute total ionization cross section of DHP (18.1 ± 0.9) × 10−16 cm2 at 100 eV energy, the absolute total and partial ionization cross sections of DHP were determined in the 5–140 eV electron energy. Moreover, a machine learning algorithm that was trained with measured cross sections from 25 different molecules was used to predict the total ionization cross section for DHP. Comparison of the machine learning simulation with the measured data showed acceptable agreement, similar to that achieved in past predictions of the algorithm.

  • Upward convergence patterns in chosen environmental-related SDGs
    • Marta Kuc-Czarnecka
    • Iwona Markowicz
    • Agnieszka Sompolska-Rzechuła
    2024 Full text ECOLOGICAL INDICATORS

    Sustainable development is a challenge facing humanity. EU countries not only strive to reach their specific objectives, but they also work collaboratively towards shared goals. There is a need to balance synergies and compromises to address these objectives effectively. When discussing countries' development and people's well-being, one often focuses on socio-economic development. However, it is crucial not to overlook the environmental repercussions and the need to care for the planet. Thus, our article pays attention to the sustainable development objectives of the “planets” group. We analysed upward convergence in the scope of the “Planet” goals, i.e. the analysis of improving the results of Member States and, at the same time, reducing the differences between them. Convergence trends were examined individually for each variable and then for all variables combined (Planet). Our article fills a research gap because, to our knowledge, analyses of the trajectories of achieving individual goals in such a context have not been analysed so far. The results of our study indicate a favourable situation in the case of six out of eight examined variables. Areas in which intensification of activities is necessary for some EU countries are an increase in energy productivity and a reduction in net greenhouse gas emissions of land use. The second stage of the study concerned the development paths of individual countries. The most challenging situation concerns the variable sdg_07_20 (final energy consumption in households per capita). In this case, as many as 12 countries belong to the weak group.

  • Usability of Mobile Applications: A Consolidated Model
    • Paweł Weichbroth
    2024 Full text IEEE Access

    Mobile devices have become an integral part of the digital ecosystem, connecting people, businesses, and information around the world in ways never before possible. In particular, smartphones, tablets and other handheld devices equipped with mobile applications have changed every aspect of our lives. Today, a user can choose from nearly five million applications available for both Android and iOS operating systems. However, only 0.5 percent of applications succeed in the marketplace. Many factors contribute to their failure, including poor design, lack of value, privacy violations, and usability issues. While usability is often identified as a major concern, there seems to be no agreement between researchers and practitioners on its nature, although many models have been developed. This paper attempts to find a consensus by synthesizing the state of the art literature. More specifically, we aim to develop a consolidated, universal usability model for mobile applications, through the lens of existing human computer interaction theory. In order to achieve this goal, our study uses a mix of qualitative and quantitative methods. Overall, the research methodology consisted of two steps. First, we conducted a systematic literature review to identify, collect, and analyze current research on mobile usability. Second, we used the meta-analysis approach to quantitatively describe the extracted data and summarize the findings. The PACMAD+3 model was developed and discussed in light of the results obtained and the PACMAD model. While our model borrows seven attributes from its ancestor, the remaining three attributes were derived from the synthesis of other studies, along with three external factors adopted from the ISO 9241-11 standard. In addition, we reviewed existing definitions of usability attributes. We expect that this unified approach will lead to a better understanding of mobile usability, including all relevant attributes and factors, thus making a significant contribution to theory. On the other hand, in practice, the PACMAD+3 model can be used to translate abstract attributes into tangible terms, which is particularly useful in empirical research focused on measuring and evaluating the usability of mobile applications.

  • Usability Testing of Mobile Applications: A Methodological Framework
    • Paweł Weichbroth
    2024 Full text Applied Sciences-Basel

    Less than five percent of all mobile applications have become successful throughout 2023. The success of a new mobile application depends on a variety of factors ranging from business understanding, customer value, and perceived quality of use. In this sense, the topic of usability testing of mobile applications is relevant from the point of view of user satisfaction and acceptance. However, the current knowledge seems to be fragmented, scattered across many papers and reports, and sometimes poorly documented. This paper attempts to fill this gap by investigating the current state of knowledge by reviewing the previous literature relevant to the research topic and developing a unified view. In particular, the methodological framework is outlined and discussed, including the discourse on settings for laboratory and field studies, data collection techniques, experimental designs for mobile usability testing, and a generic research framework. Therefore, the paper contributes to both the theory and practice of human–computer interaction by providing methodological foundations for usability testing of mobile applications, paving the way for further studies in this area. Moreover, the paper provides a better understanding of the related topics, in particular shedding light on methodological foundations, key concepts, challenges, and issues, equipping readers with a comprehensive knowledge base to navigate and contribute to the advancement of the field of mobile usability.

  • User experience evaluation study on the quality of 1K, 2K, and 4K H.265/HEVC video content
    • Przemysław Falkowski-Gilski
    • Tadeus Uhl
    • Christian Hoppe
    2024 Full text Zeszyty Naukowe Akademii Morskiej w Szczecinie

    Nowadays, most content creators focus on distributing rich media at the highest possible resolution. Currently, the majority of sold consoles, media players, computer hardware, as well as displays and TVs are advertised as 4K-compatible. The same trend is observed in the case of popular online streaming services and terrestrial TV broadcasts. Generally speaking, it is assumed that higher bitrates provide higher subjective judgements. In this paper, we present the results of a user experience (UX) evaluation study on the quality of video content coded and transmitted in different resolutions in the internet protocol (IP) environment. The image resolutions include 1K (1920×1080 pixels; full-HD), 2K (2560×1440 pixels; wide-QHD), and 4K (3840×2160 pixels; ultra-HD) content that are processed in the H.265/HEVC (high-efficiency video coding) format. A subjective evaluation is carried out in a laboratory consisting of 20 iMacs with a 21.5-inch 4K Retina (4096×2304 pixels) display. The group of viewers included 28 individuals aged between 21‒35 years old, comprising people with and without visual impairments. The obtained UX results are compared with previous experiments, including both objective quality of service (QoS) and subjective quality of experience (QoE), as well as the impact of down-scaling to 1K from 2K and 4K. The outcomes of this study may be of particular interest to any party interested in video content processing and distribution, as well as consumption and storage.

  • 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 Mazurkiewicz
    • Anna Kaczorowska
    • Anna Rubczak
    • Justyna Wieczerzak
    • Dorota 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.

  • 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.

  • 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.

  • Virtual tour as an innovative tool for architectural education - from understanding heritage to creativity stimulation
    • Karolina Życzkowska
    • Doria Elisabetta
    • Justyna Borucka
    2024 Global Journal of Engineering 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).

  • 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.

  • 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.

  • 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.

  • 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.

  • 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 stosowanych praktyk rolniczych na dopływ wód podziemnych oraz azotanów do Zatoki Puckiej
    • Dawid Potrykus
    2024 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 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 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.

  • 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.

  • Wytwarzanie i modyfikacja powierzchni porowatych struktur tytanowych przeznaczonych na implanty
    • Magda Rościszewska
    2024 Full text

    Celem pracy było wytworzenie stopu Ti-13Nb-13Zr z wykorzystaniem technologii selektywnego topienia laserowego (SLM) oraz jego biofunkcjonalizacja za pomocą utleniania mikrołukowego (MAO), a następnie określenie wpływu parametrów procesowych na właściwości otrzymanych materiałów pod kątem ich zastosowania na implanty. Oceniono wpływ napięcia, natężenia i czasu procesu MAO przeprowadzanego w elektrolicie zawierającym wapń i fosfor na charakterystykę warstw. Następnie zbadano wpływ bioaktywnych dodatków srebra i galu na charakterystykę otrzymanych warstw, oraz porównano właściwości uzyskanych warstw MAO w zależności od metody wytwarzania materiału referencyjnego. Metodyka badań obejmowała charakteryzację topografii powierzchni (SEM, AFM), składu chemicznego (EDS) i fazowego (XRD), pomiary kąta zwilżania (tensjometr optyczny), badania mechaniczne (nanoindentacja i test zarysowania), ocenę wstępnej bioaktywności (test immersji), badania uwalniania jonów (MP-AES), test żywotności komórek (MTT) oraz ocenę cytotoksyczności (zliczanie kolonii bakterii). Badania wykazały, że warstwy MAO, zawierające wapń i fosfor z dodatkiem srebra lub galu, wytworzone przy odpowiedniej kombinacji parametrów procesu zwiększają biozgodność oraz aktywność biologiczną implantu tytanowego, a charakterystyka materiałów wytworzonych SLM, w tym ich mikrostruktura, istotnie wpływa na właściwości warstw MAO.

  • Wyzwania współpracy z robotem jako członkiem zespołu
    • Beata Krawczyk-Bryłka
    • Krzysztof Nowicki
    2024 Full text Zeszyty Naukowe Uniwersytetu Ekonomicznego w Krakowie

    – Cel: Ocena, jakie są przekonania dotyczące współpracy z robotami w zespole, jakie są obawy i oczekiwania związane z „zatrudnianiem” robotów. – Metodyka badań: Badania ilościowe zrealizowane z zastosowaniem kwestionariusza ankiety w grupie 593 specjalistów IT. – Wyniki badań: Roboty nadal traktowane są głównie jako narzędzia, nie jako podmioty uczestniczące w pracy zespołu. Przekonanie, że obecność robota w zespole nie wyeliminuje człowieka, a raczej zastąpi go w wykonywaniu niebezpiecznych i niekomfortowych zadań i zapewni przestrzeń do skupienia się na bardziej kreatywnych działaniach to podstawy pozytywnej postawy do zatrudniania robotów w zespołach. – Wnioski: Konieczne jest budowanie świadomości twórców robotów, że będą one członkami zespołów, które wchodzą w relacje z ludźmi, z którymi realizują zadania zawodowe. Przygotowanie do współpracy w takich zespołach to ważne współczesne zadanie z zakresu zarządzania zasobami ludzkimi. – Wkład w rozwój dyscypliny: Badania dotyczące zespołów, w których roboty współpracują z ludźmi w roli członków zespołów pracowniczych to nowość w polskiej literaturze przedmiotu. Artykuł może być źródłem inspiracji do dalszej eksploracji tego obszaru badawczego.

  • YADE - An extensible framework for the interactive simulation of multiscale, multiphase, and multiphysics particulate systems
    • Vasileios Angelidakis
    • Katia Boschi
    • Karol Brzeziński
    • Robert Caulk
    • Bruno Chareyre
    • Carlos Andrés del Valle
    • Jérôme Duriez
    • Anton Gladky
    • Dingeman L.H. van der Haven
    • Jan Kozicki
    • Gerald Pekmezi
    • Luc Scholtès
    • Klaus Thoeni
    2024 Full text COMPUTER PHYSICS COMMUNICATIONS

    This contribution presents the key elements of YADE, an extensible open-source framework for dynamic simulations. During the past 19 years, YADE has evolved from "Yet Another Dynamic Engine"' to a versatile multiscale and multiphysics solver, counting a large, active, and growing community of users and developers. The computationally intense parts of the source code are written in C++, using flexible object models that allow for easy implementation of new features. The source code is wrapped in Python, equipping the software with an interactive kernel used for rapid and concise scene construction, simulation control, post-processing, and debugging. The project, including documentation and examples, is hosted on https://yade-dem.org, while the source code is freely available on GitLab. Over the last decade, YADE has expanded in terms of capabilities thanks to the contribution of many developers from different fields of expertise, including soil and rock mechanics, chemical engineering, physics, bulk material handling, and mineral processing. The rapid growth of YADE can be attributed to (1) the careful and robust design of the framework core, (2) a continuous integration pipeline with fully embedded thorough tests which are executed upon each merge request, ensuring stable compilation for various operating systems, and (3) user-friendliness, facilitated by the Python interface, detailed documentation, and rigorous user support. In this paper, we review the main features of YADE, highlighting its versatility in terms of applications, its flexibility in terms of code development, as well as recent improvements in terms of computational efficiency.

  • Zaawansowany układ samoczynnego załączania rezerwy oparty na sterowniku WAGO PFC200
    • Andrzej Augusiak
    • Remigiusz Izbaner
    • Jakub Labudda
    2024 Wiadomości Elektrotechniczne

    Artykuł opisuje projekt i wykonanie układu samoczynnego załączania rezerwy (SZR) na potrzeby stacji elektroenergetycznej Laboratorium LINTE^2 na Politechnice Gdańskiej. Układ SZR został zbudowany na podstawie modułowego sterownika PLC WAGO PFC200. W artykule omówiono zasadę działania układu, a także jego program sterowania i aplikację panelu HMI, opracowane w zintegrowanym środowisku programistycznym CoDeSys 3.5. Oprócz zadań typowego układu SZR (takich jak sterowanie łącznikami, czy blokady przed wykonaniem niedozwolonych operacji łączeniowych), zaproponowany algorytm sterowania realizuje zaawansowane funkcje dodatkowe. Na szczególną uwagę zasługuje współpraca układu SZR z instalacją fotowoltaiczną, którą układ ten odłącza od sieci podczas realizacji zasilania rezerwowego z jednego z dwóch agregatów prądotwórczych. Innym przykładem zaawansowanych funkcji układu SZR jest wybór agregatu rezerwowego na podstawie informacji o ilości paliwa dostępnego w zbiornikach.