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  • A comparative analysis of numerically simulated and experimentally measured static responses of a floating dock
    • Jianan Zhang
    • Xueliang Wen
    • Aleksander Kniat
    • Muk Chen Ong
    2024 Ships and Offshore Structures

    Two numerical methods, dynamic and static analyses, are proposed to calculate the static responses of a floating dock under different ballast water distributions. Model-scale experimental tests were conducted to compare with these numerical methods. The dynamic analysis includes a 6-degree-of-freedom (6-DOF) model, a hydrostatic force model and a hydrodynamic force model to simulate the dock's freely floating processes. The dock's equilibrium position is identified when the difference in the dock’s motions between two successive time steps is below a specified tolerance value. In the static analysis, the static equilibrium equations in draught, heel, and trim are solved using the Newton-Raphson method. Both dynamic and static results of the draughts at the four corners, heel, and trim are in good agreement with the corresponding experimental results, which shows the reliability of the proposed numerical methods. Moreover, the static analysis exhibits quicker convergence, requiring fewer iteration steps than the dynamic analysis.

  • A Comparative Study of Precision Surface Grinding Using Additively Fabricated Acrylonitrile–Butadiene–Styrene (ABS) Wheels with Continuous and Serrated Working Surfaces
    • Dawid Zieliński
    • Mariusz Deja
    • Mateusz Zator
    2024 Pełny tekst Materials

    Nowadays, high requirements imposed by mechanical components make it necessary to develop modern production methods. Additive technologies have been dynamically developing in recent years, showing many advantages associated with the fabrication of elements with complex ge-ometries and structures. One of the areas where the potential of additive technologies is exploited is the rapid tooling sector, which is based on the rapid production of tools and components used in various manufacturing methods. Currently, apart from industrial additive fabrication using metal and plastic powders, desktop and low-cost devices for additive manufacturing are gaining more and more importance in the production of functional elements. This paper presents the experi-mental results obtained from testing the micro-abrasive acrylonitrile–butadiene–styrene ABS tools fabricated by fused filament fabrication (FFF) technology and reinforced with SD 28/20 diamond grains uniformly distributed on the working surface of the tools after they were made. Precision surface grinding operations of 41Cr4 alloy steel were carried out on a portable five-axis CNC milling machine using wheels with continuous and serrated working surfaces. The tool with a serrated working surface enabled a more efficient material removal and produced a better surface finish. In particular, a low wear rate of both FFF-printed tools was confirmed after all experiments. Promising results were obtained, showing the potential for a wider industrial application of the tested tools.

  • A Comparison of Directional Beamforming Capabilities: High-Order Ambisonic Microphone vs. Shotgun Microphones
    • Paweł Perkowski
    • Paweł Pławczyk
    • Bartłomiej Mróz
    • Józef Kotus
    • Ewa Kujawska
    • Kamil Klonowski
    • Radosław Wierzbicki
    • Patryk Kosior
    2024

    This article presents the practical implications of the directional beamforming capability of a higher-order ambisonic microphone compared with popular shotgun microphones. Five different microphones were used in the study: Sennheiser MKH 416, Rode NTG2, Panasonic AG-MC200, Zoom SGH-6, and Zylia ZM-1 (ambisonic microphone). The results highlight the versatility of higher-order ambisonics for non-immersive use, which allows for beamforming in any direction even in post-production, as opposed to typical shotgun recordings. Measurements indicate that shotgun microphones show directional characteristics with apparent frequency-dependent directivity. The Zylia microphone has 5 beamforming modes, among which the S1 and S2 modes exhibit directional characteristics similar to shotgun microphones.

  • A Comprehensive Approach to Azo Dichlorotriazine Dye Treatment: Assessing the Impact of Physical, Chemical, and Biological Treatment Methods through Statistical Analysis of Experimental Data
    • Gamal K. Hassan
    • Montaser Y. Ghaly
    • Ghada E. Ahmed
    • Rehab M. Mohamed
    • Heba A. El-Gawad
    • Przemysław Kowal
    • Hussein Al-Hazmi
    • Ahmed A. Afify
    2024 Water

    This exploration investigates integrated treatment systems combining advanced oxidation processes (Fenton and photo-Fenton) with biological methods for the effective elimination of stubborn organic compounds in simulated textile wastewater composed of azo Dichlorotriazine dye. A comprehensive optimization of key process factors including catalyst dosage, hydrogen peroxide quantity, irradiation duration, etc. was systematically conducted for both Fenton and photo-Fenton processes to realize maximum COD and color removal. Under ideal conditions (0.4 g/L photocatalyst, 1 mL/L H2O2, and 75-Watt UV intensity for 60 min), the photo-Fenton process realized 80% COD elimination and complete decolorization, meeting industrial discharge limits without needing extra biological treatment. Statistical models correlating process parameters to treatment efficiency were developed, giving important design insights. For Fenton, effluent COD exceeded discharge thresholds, so a post-biological treatment using activated sludge was essential to comply with regulations. This integrated Fenton–biological scheme utilizes synergism between chemical and biological processes for enhanced overall treatment. Notable economic benefits were achieved by photo-Fenton over conventional UV-only and UV/H2O2 methods regarding energy consumption and operating costs. Overall, this pioneering work successfully proves integrated advanced oxidation–biological systems as a superior, sustainable alternative to traditional techniques for economically removing obstinate pollutants, such as azo Dichlorotriazine dye, as it is a simulated textile wastewater treatment used to satisfy environmental standards.

  • A Comprehensive Review: Applications of the Kozeny–Carman Model in Engineering with Permeability Dynamics
    • Maryam Rehman
    • Muhammad Bilal Hafeez
    • Marek Krawczuk
    2024 ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING

    In this review article, we investigate the dynamic nature of the Kozeny–Carman Model concerning permeability and its application in engineering contexts. Providing insights into the changing dynamics of permeability within mining, petroleum, and geotechnical engineering, among other engineering applications. While some are complex and require additional modifcations to be applicable, others are simple and still function in specifc situations. Therefore, having a thorough understanding of the most recent permeability evolution model would help engineers and researchers in fnding the right solution for engineering issues for prospects. The permeability evolution model Kozeny–Carman (KC) put forth by previous and current researchers is compiled in this paper, with a focus on its features and drawbacks

  • A COMPREHENSIVE REVIEW OF LIFE CYCLE ASSESSMENT AND ENERGY EFFICIENCY IN 3D PRINTING FOR CONSTRUCTION: CURRENT STATE, BENEFITS, LIMITATIONS, AND FUTURE OUTLOOK
    • Semahat Merve Top
    • Jan Cudzik
    2024 Pełny tekst Journal of Green Building

    The agenda of Industry 4.0 strongly affects design and construction at all its phases, and three-Dimensional Printing (3DP) is an essential part of it. The emerging technology has the potential to become a more valid and accepted form of construction. This research is based on a literature review regarding the relationships between the concepts of Life Cycle Assessment (LCA) and energy efficiency for 3DP in construction research to understand the developments. Systematic bibliometric and scientometric analyses are used as data analysis techniques to make a detailed comparison. The comparison allowed for assessing and determining the current state, benefits, limitations, and future outlook. Current research is based on insights examining materials first (80%), followed by walls (15%), buildings (11%), and 3DP technology (6%). The findings highlight that 3DP technology offers significant advantages in terms of time efficiency, reliability, ecological impact, and sustainability within the construction industry. However, several challenges, such as the complexity of material mixture content design, the lack of standardized 3DP materials and codes, and the limited availability of experts in the field, prevent its widespread adoption. Further advancement of 3DP requires the development of standards, policies, training and materials for its full implementation in the construction industry.

  • A Comprehensive Review of Reactive Flame Retardants for Polyurethane Materials: Current Development and Future Opportunities in an Environmentally Friendly Direction
    • Paulina Parcheta-Szwindowska
    • Julia Habaj
    • Izabela Krzemińska
    • Janusz Datta
    2024 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Polyurethanes are among the most significant types of polymers in development; thesematerials are used to produce construction products intended for work in various conditions. Nowa-days, it is important to develop methods for fire load reduction by using new kinds of additivesor monomers containing elements responsible for materials’ fire resistance. Currently, additiveantipyrines or reactive flame retardants can be used during polyurethane material processing. Theuse of additives usually leads to the migration or volatilization of the additive to the surface of thematerial, which causes the loss of the resistance and aesthetic values of the product. Reactive flameretardants form compounds containing special functional groups that can be chemically bonded withmonomers during polymerization, which can prevent volatilization or migration to the surface of thematerial. In this study, reactive flame retardants are compared. Their impacts on polyurethane flameretardancy, combustion mechanism, and environment are described.

  • A Comprehensive Review on DC Fast Charging Stations for Electric Vehicles: Standards, Power Conversion Technologies, Architectures, Energy Management, and Cybersecurity
    • Gabriele Arena
    • Andrii Chub
    • Mykola Lukianov
    • Ryszard Strzelecki
    • Dmitri Vinnikov
    • Giovanni De Carne
    2024 Pełny tekst IEEE Open Journal of Power Electronics

    This paper aims to review the main research points regarding DC fast charging stations. At the beginning, the paper addresses an overview of DC fast charging standards, galvanic isolation, EV powertrain, and some examples of real DC fast chargers. This part highlights that DC fast chargers are usually connected to an AC network or microgrid, whereas DC microgrids would be a better choice to increase the charging efficiency and reduce the costs. However, the lack of standards in terms of protection and metering made their spread limited for the moment. Moreover, the paper describes the power converter topologies typically adopted in DC fast charging stations and emerging solutions to interface EVs with both 400 V and 800 V powertrains. Then, the paper explains the main architectural features of DC fast charging stations connected to DC networks or microgrids because of their potential to become the standard infrastructure in this field. Furthermore, the energy management strategies for DC fast charging stations are discussed, taking into account their relevant goals. Finally, cybersecurity issues of charging stations are covered, also considering their impact on grid and electric vehicle supply equipment, and providing a particular discussion regarding DC fast charging stations.

  • A comprehensive review on economic, environmental impacts and future challenges for photovoltaic-based electric vehicle charging infrastructures
    • Haseeb Rashid
    • Liu Ming Hua
    • Lyu Guanghua
    • Rija Hasan
    • Abdulrahman AlKaseem
    • Aqsa Ali
    • Syed Hadi Hussain Shah
    • Shoaib Shaikh
    • Arsalan Muhammad Soomar
    • Piotr Musznicki
    2024 Pełny tekst Frontiers in Energy Research

    In this paper, a comprehensive review of the impacts and imminent design challenges concerning such EV charging stations that are based on solar photovoltaic infrastructures is presented, which is based on state-of-the-art frameworks for PV-powered charging stations and the latest case studies. The main factors that are targeted in this review are the management of an EV charging system that is a composite of PV and public grid, as well as a charging system business model that can affect consumer behavior by charging at different rates and the best design infrastructure for a PV electric vehicle charging services. The economic, environmental, and social impacts caused by the installation of PVdriven charging infrastructures are also compared. Moreover, the framework for recently emerging vehicle-to-grid and vehicle-to-home services, as well as the integration of these frameworks, is discussed. Finally, survey results for future EV demand and its public acceptance are presented. Appertaining to these issues, the case studies highlight that EV transportation between parking lots and charging stations is necessary to make the best use of the available charging stations. Statistically, in this study, it was inferred that there are no limitations on the amount of EV battery capacity that can be stored, and users of EVs can charge in both slow and fast modes. Furthermore, V2G systems are not suitable for widespread industrial use. Moreover, finding solutions and overcoming numerous obstacles remain unaddressed issues, and the size of the EV industry must reach a certain level to make profitable sales of V2B, V2H, V2G, and other V2X systems. The collected statistics indicate that although respondents generally have a favorable opinion of the mobility applications powered by photovoltaic cells, it seems unlikely that they will use them anytime soon.

  • A Computational Analysis of the Proton Affinity and the Hydration of TEMPO and Its Piperidine Analogs
    • Abolfazl Shiroudi
    • Maciej Śmiechowski
    • Jacek Czub
    • Mohamed A. Abdel-Rahman
    2024 CHEMPHYSCHEM

    The study investigated the impact of protonation and hydration on the geometry of nitroxide radicals using B3LYP and M06-2X methods. Results indicated that TEMPO exhibited the highest proton affinity in comparison to TEMPOL and TEMPONE. Two pathways contribute to hydrated protonated molecules. TEMPO shows lower first enthalpies of hydration (ΔH1-M), indicating stronger H-bonding interactions, while TEMPONE shows higher values, indicating weaker interactions with H2O. Solvent effects affect charge distribution by decreasing their atomic charge. Spin density (SD) is primarily concentrated in the NO segment, with minimal water molecule contamination. Protonation increases SD on N-atom, while hydration causes a more pronounced redistribution for water molecules. The stability of the dipolar structure (>N•+-O-) is evident in SD redistributions. The frontier molecular orbital (FMO) analysis of TEMPONE reveals a minimum EHOMO-LUMO gap (EH-L), enhancing the piperidine ring's reactivity. TEMPO is the most nucleophilic species, while TEMPONE exhibits strong electrophilicity. Transitioning from NO radicals to protonated forms increases the EH-L gap, indicating protonation stabilizes FMOs. Increased water molecules make the molecule less reactive, while increasing hydration decreases this energy gap, making the molecule more reactive. A smaller EH-L gap indicates the compound becomes softer and more prone to electron density and reactivity changes.

  • A Concept of Thermal Effort for Heat-Induced Metal Plasticity
    • Waldemar Dudda
    • Piotr Józef Ziółkowski
    • Paweł Ziółkowski
    • Mateusz Bryk
    • Janusz Badur
    2024 Materials

    This paper proposes a new concept of material effort that considers heat-induced plasticity for heat-resistant steels. These steels indicate a strength differential effect, a stress shearness effect, pressure sensitivity, and other features. Therefore, a three-parameter, temperature-dependent yield function was presented and, next, analytically and geometrically researched. To validate the accuracy of the formulated yield function, experiments were conducted with the designed specimens to characterize the heat-resistant steels St12T and 26H2MF, which underwent simple shear, uniaxial strain tension, and compression tests. The yield function was calibrated by using a simple analysis. Next, the calibrated constitutive equations were used to numerically determine the load–stroke responses of different tests. The numerical analysis showed that the proposed yield function based on three parameters could accurately describe the thermal effort in various loading conditions from the onset of yielding to the ultimate rupture. Accordingly, the proposed yield function is recommended to model material strength under various thermal loading conditions.

  • A dissimilar welded joint of grade 92 steel and AISI 304L steel obtained using IN82 buttering and IN617 fller: relationship of microstructure and mechanical properties
    • Hardik Sanjay Surkar
    • Amit Kumar
    • Sachin Sirohi
    • Shailesh M. Pandey
    • Aleksandra Świerczyńska
    • Dariusz Fydrych
    • Chandan Pandey
    2024 Archives of Civil and Mechanical Engineering

    Unfavourable operating conditions of equipment in the energy industry resulting from high-temperature loads determine the need to use special materials and technological solutions, including welding procedures. In this article, buttering using IN82 (ERNiCr-3) consumables was proposed as a method to improve the weldability of grade 92 steel joined by the gas tungsten arc welding (GTAW) process with AISI 304L (IN617 fller). The microstructural characterization of samples was carried out using an optical microscope, scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy. The welded joint was further characterized by hardness, tensile (room temperature and at 620 °C temperature) and impact tests. Additionally, the fracture surfaces of tensile and impact tests were studied by SEM. Despite the confrmation of the difusion of alloying elements and signifcant changes in their concentration, which indicates the formation of Ti and Nb-rich phases, no welding imperfections were detected and favourable joint structures and acceptable properties were obtained. In particular, this concerns the limitation of the formation of brittle structures and the elimination of the untempered martensitic layer. At the same time, there was a signifcant decrease in the maximum hardness of heat-afected zone (HAZ) on the grade 92 steel side to a relatively low value of 310 HV, and a minimum tensile strength criterion of 600 MPa was achieved with a simultaneous increase in ductility (35% elongation) of the joint. Comparatively, when compared to a non-buttered welded joint, the joint produced with a buttering layer exhibited an increase in the elongation and impact toughness of the welded joint without any compromise in ultimate tensile strength (Sut). The fracture surface of tensile and impact-tested specimens was also characterized using SEM/EDS. Summarizing all the results, it can be concluded that the proposed GTAW procedure of grade 92 and 304L steels can be used in extreme working conditions, in ultra-supercritical power units or the petrochemical and chemical industries.

  • A Finite Element Approach for Wave Propagation in Elastic Solids
    • Arkadiusz Żak
    2024

    This book focuses on wave propagation phenomena in elastic solids modelled by the use of the finite element method. Although the latter is a well-established and popular numerical tool used by engineers and researchers all around the word the process of modelling of wave propagation can still be a challenge. The book introduces a reader to the problem by presenting a historical background and offering a broad perspective on the development of modern science and numerical methods. The principles of wave phenomena are clearly presented to the reader as well as the necessary background for understanding the finite element method, which is the following chapter of the book is viewed from the modeller point-of-view. Apart from the principles the book also addresses more advanced topics and problems including the use of the spectral-finite element method, the spline-based finite element method as well as the problems of undesired and hidden properties of discrete numerical models.

  • A framework for risk matrix design: A case of MASS navigation risk
    • Cunlong Fan
    • Jakub Montewka
    • Di Zhang
    • Zhepeng Han
    2024 ACCIDENT ANALYSIS AND PREVENTION

    Risk matrix, a tool for visualizing risk assessment results, is essential to facilitate the risk communication and risk management in risk-based decision-making processes related to new and unexplored socio-technical systems. The use of an appropriate risk matrix is discussed in the literature, but it is overlooked for emerging technologies such as Maritime Autonomous Surface Ships (MASS). In this study, a comprehensive framework for developing a risk matrix based on fuzzy Analytic Hierarchy Process (AHP) is proposed. In this framework, a linear function is defined where the risk index is treated as a response variable, while the probability and consequence indices are explanatory variables, with weights of these two indices representing their importance on given risk level. This significance is assessed by experts and quantified using AHP in interval type 2 fuzzy environment. A continuous risk diagram is then created and converted into a risk matrix that can be improved. To verify the feasibility of the proposed framework, a risk matrix is designed in the context of MASS grounding. The results show that the proposed approach is feasible. Our discussion results can provide new insights for the design of risk matrices and promote the management of MASS navigational risks.

  • A framework to analyse the probability of accidental hull girder failure considering advanced corrosion degradation for risk-based ship design
    • Krzysztof Wołoszyk
    • Floris Goerlandt
    • Jakub Montewka
    2024 RELIABILITY ENGINEERING & SYSTEM SAFETY

    Ship’s hull girder failure could result from maritime accident that can cause human life loss, environmental disaster, and major economic impacts. In risk-based ship design paradigm, accounting for rare phenomena (e.g. ship-ship collision or grounding) is important to provide safe and durable structure. In-service corrosion-induced hull degradation should be considered at the design stage, as it can significantly affect structural strength. The current study presents a novel framework to estimate the probability of ship hull girder failure, accounting for novel corrosion modelling techniques and accidental damage. The associated uncertainties are considered using statistical sampling from evidence-based distributions. A state-of-the-art deterministic model for ultimate strength calculation is applied using Monte Carlo simulation approach, resulting in the probability of hull failure through a reliability assessment. Wave and still-water bending moments are considered random variables. Two case studies of tanker ships with varying sizes are executed to show the applicability of the proposed framework. The results indicate that proper consideration of corrosion is of high importance, as ageing can significantly increase the probability of failure if accidental damage happens. Therefore, whereas future research and model refinement are discussed, the presented framework can serve for risk-based ship design tool and assess existing structures’ safety.

  • A gap waveguide-based mechanically reconfigurable phase shifter for high-power Ku-band applications
    • Ali Farahbakhsh
    • Davood Zarifi
    • Michał Mrozowski
    2024 Scientific Reports

    This paper presents a novel design of a low-loss, reconfgurable broadband phase shifter based on groove gap waveguide (GGW) technology. The proposed phase shifter consists of a folded GGW and three bends with a few pins forming the GGW and one bend attached to a movable plate. This movable plate allows for adjustments to the folded waveguide length, consequently altering the phase of electromagnetic waves. The advantage of GGW technology is that it does not require electrical contact between diferent parts of a structure. Therefore, it enables the moving parts to slide freely without electromagnetic energy leakage, resulting in improved insertion loss in high-power applications. In addition, in the proposed design, the position of the input and output waveguide ports of the phase shifter remains fxed, which is advantageous from a practical point of view. As shown by measurement and simulation results, there is nearly 37% impedance bandwidth with the highest insertion loss of 0.6 dB, and the developed device has a maximum phase shift of 770° at the center frequency of 13GHz. The phase shifter can be used for various radar and satellite applications that require phase control, such as beamforming networks and phased array antennas.

  • A green route for high-performance bio-based polyurethanes synthesized from modified bio-based isocyanates
    • Joanna Brzoska
    • Joanna Smorawska
    • Ewa Głowińska
    • Janusz Datta
    2024 INDUSTRIAL CROPS AND PRODUCTS

    The need for sustainability and a circular economy leads to the development of innovative greener materials and technologies. This paper is focused on a novel class of bio-based polyurethanes (PUs) synthesized with the use of bio-monomers including bio-based isocyanates. The novelty of this work is related to the usage of bio-based modified isocyanate via a two-step solvent-free synthesis of novel cast bio-based poly(ester-urethanes) and poly(ether-urethanes). The designed and prepared bio-based PUs were analysed in terms of their chemical structure, thermal stability, mechanical and thermomechanical properties. Fourier transform infrared spectroscopy confirmed the formation of urethane groups and allowed the calculation of the carbonyl index and the degree of phase separation. Differential scanning calorimetry and X-ray diffraction indicated the amorphous behavior of the obtained bio-based materials. It was established that not only the thermal stability but also the degradation steps depended on the structure of the hard segments and the phase separation between hard and soft segments. The modification of hard segments was also revealed in the results of thermomechanical and mechanical behavior of bio-PU which indicated a mixed phase structure.

  • A hierarchical observer for a non-linear uncertain CSTR model of biochemical processes
    • Mateusz Czyżniewski
    • Rafał Łangowski
    2024 Pełny tekst International Journal of Applied Mathematics and Computer Science

    The problem of estimation of unmeasured state variables and unknown reaction kinetic functions for selected biochemical processes modelled as a continuous stirred tank reactor is addressed in this paper. In particular, a new hierarchical (sequential) state observer is derived to generate stable and robust estimates of the state variables and kinetic functions. The developed hierarchical observer uses an adjusted asymptotic observer and an adopted super-twisting sliding mode observer. The stability of the proposed hierarchical observer is investigated under uncertainty in the system dynamics. The stability analysis of the estimation error dynamics is carried out based on the methodology associated with linear parameter-varying systems and sliding mode regimes. The developed hierarchical observer is implemented in the Matlab/Simulink environment and its performance is validated via simulation. The obtained satisfactory estimation results demonstrate high effectiveness of the devised hierarchical observer.

  • A learning community model: the Center for Innovative Education supporting academic didactics at Gdańsk University of Technology, Poland
    • Joanna Mytnik
    • Barbara Wikieł
    • Mariusz Kaczmarek
    2024 Global Journal of Engineering Education

    The current digital transformation requires academics to apply their pedagogical and technological skills to their teaching and professional development to address the newly emerging needs of the digital era. This study aims to analyse the operating model of the Center for Innovative Education (CIE) at Gdańsk University of Technology (Gdańsk Tech), Poland, as an incubator for professional development of academic staff at Gdańsk Tech, and outline the programmes carried out at the CIE. The focus is on systemic actions capable to elicit innovation at an organisational and personal level, including community building, higher education trend analyses, evidence-based professional training, designing new methods and tools for innovative teaching and appreciation programmes. The CIE’s offer extends to well-being support and providing measures against professional burnout. The establishment of the CIE enabled academic teachers at Gdańsk Tech to improve their professional competence and build a strong peer-learning community.

  • A Low-Profile 3-D Printable Metastructure for Performance Improvement of Aperture Antennas
    • Md Yeakub Ali
    • Ali Lalbakhsh
    • Sławomir Kozieł
    • Łukasz Gołuński
    • Foez Ahmed
    • Mohsen Asadnia
    2024 Pełny tekst Scientific Reports

    In order to increase the radiation performance of aperture-type antennas, this paper demonstrates a low-profile, planar, single-layer, three-dimensional (3-D) printable metastructure. The proposed hybridized metastructure is highly transparent as it is made out of novel hybrid meta-atoms having transmission coefficient magnitudes greater than -0.72 dB and fully complies with the near-field phase transformation principle. The hybridized design approach makes the metastructure planar, low-profile, light in weight, and compatible with additive printing technology. For the proof-of-concept, such metastructure is developed and numerically verified to enhance the radiation performance of a resonant cavity antenna (RCA). With the proposed metastructure, the peak directivity of the RCA is improved by 8.6 dBi (from 11.4 dBi to 20 dBi) at the operating frequency of 12.4 GHz. The aperture efficiency and 3-dB directivity bandwidth of the RCA with the metastructure are 41.46% and 16.5%, respectively. Using readily accessible thermoplastics or polymers and copper with cost-effective fused deposition modeling (FDM) 3-D printing technology, the proposed planar hybridized metastructure can be prototyped commercially.

  • A Low-Profile Metal-backed Dipole Loaded with Closely Coupled Arc-shaped Open Stubs for On-metal Tag Design with Wide Frequency Tuning Capability
    • Fuad Erman
    • Sławomir Kozieł
    • Eng-Hock Lim
    • Leifur Leifsson
    • Effariza Hanafi
    • Muthukannan Murugesh
    2024 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    This research has presented a single-layer metal-backed dipole antenna, which consists of a feedline loaded with two pairs of closely-coupled arc-shaped open stubs, for designing a metal-mountable tag that features tuning capability over a wide range of frequency. Here, the stubs can generate sufficient inductive reactance for bringing down the tag resonant frequency tunable in both the regulated UHF RFID passbands (North American (NA) and Lower European (LEu) standards). Adjusting the stubs’ length can be utilized as a simple and effective tuning mechanism, enabling broadband frequency adjustment in between the two major spectra in a straightforward manner, while maintaining a maximum power transmission coefficient (τ=1). In addition, the proposed antenna structure is easy to construct. The tuning mechanism has enabled the antenna to match well with any commercial RFID chips, and it does not require the use of any external lumped components or shorting elements (vias or stubs). The proposed tag can be easily fabricated using an inexpensive flexible polytetrafluoroethylene (PTFE) substrate, which is broadly adopted by the RFID industry. Stable read performance is achievable, providing freedom of frequency tuning without the need to modify the radiator structure. The volume of the tag is reasonably small:   (28)2  1.5 mm3. It has a measured detection distance is 9.75 m (4 W EIRP) on metal surface in the NA RFID passband while 8.41 m (3.24 W EIRP) in the LEu passband.

  • A Machine Learning Approach for Estimating Overtime Allocation in Software Development Projects
    • Hammed Mojeed
    • Rafał Szłapczyński
    2024 Pełny tekst

    Overtime planning in software projects has traditionally been approached with search-based multi-objective optimization algorithms. However, the explicit solutions produced by these algorithms often lack applicability and acceptance in the software industry due to their disregard for project managers' intuitive knowledge. This study presents a machine learning model that learns the preferred overtime allocation patterns from solutions annotated by project managers and applied to four publicly available software development projects. The model was trained using 1092 instances of annotated solutions gathered from software houses, and the Random Forest Regression (RFR) algorithm was used to estimate the PMs' preference. The evaluation results using MAE, RMSE, and R2 revealed that RFR exhibits excellent predictive power in this domain with minimal error. RFR also outperformed the baseline regression models in all the performance measures. The proposed machine learning approach provides a reliable and effective tool for estimating project managers' preferences for overtime plans.

  • A machine learning approach to classifying New York Heart Association (NYHA) heart failure
    • Krystian Jandy
    • Paweł Weichbroth
    2024 Pełny tekst Scientific Reports

    According to the European Society of Cardiology, globally the number of patients with heart failure nearly doubled from 33.5 million in 1990 to 64.3 million in 2017, and is further projected to increase dramatically in this decade, still remaining a leading cause of morbidity and mortality. One of the most frequently applied heart failure classification systems that physicians use is the New York Heart Association (NYHA) Functional Classification. Each NYHA class describes a patient’s symptoms while performing physical activities, delivering a strong indicator of the heart performance. In each case, a NYHA class is individually determined routinely based on the subjective assessment of the treating physician. However, such diagnosis can suffer from bias, eventually affecting a valid assessment. To tackle this issue, we take advantage of the machine learning approach to develop a decision-tree, along with a set of decision rules, which can serve as additional blinded investigator tool to make unbiased assessment. On a dataset containing 434 observations, the supervised learning approach was initially employed to train a Decision Tree model. In the subsequent phase, ensemble learning techniques were utilized to develop both the Voting Classifier and the Random Forest model. The performance of all models was assessed using 10-fold cross-validation with stratification.The Decision Tree, Random Forest, and Voting Classifier models reported accuracies of 76.28%, 96.77%, and 99.54% respectively. The Voting Classifier led in classifying NYHA I and III with 98.7% and 100% accuracy. Both Random Forest and Voting Classifier flawlessly classified NYHA II at 100%. However, for NYHA IV, Random Forest achieved a perfect score, while the Voting Classifier reported 90%. The Decision Tree showed the least effectiveness among all the models tested. In our opinion, the results seem satisfactory in terms of their supporting role in clinical practice. In particular, the use of a machine learning tool could reduce or even eliminate the bias in the physician’s assessment. In addition, future research should consider testing other variables in different datasets to gain a better understanding of the significant factors affecting heart failure.

  • A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides
    • Nurhasima Phirisi
    • Justyna Płotka-Wasylka
    • Opas Bunkoed
    2024 JOURNAL OF CHROMATOGRAPHY A

    A magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@NGQDs@ Fe3O4–NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding with triazines. The MIP layer provided highly specific recognition sites for the selective adsorption of three target triazines. The extracted triazines were determined by high-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD). The developed method exhibited linearity from 1.5 to 100.0 μg L 1 with a detection limit of 0.5 μg L 1. Recoveries from spiked fruit juice samples were in the range of 80.1– 108.4 %, with a relative standard deviation of less than 6.0 %. The developed MMIP adsorbent demonstrated good selectivity, high extraction efficiency, ease of fabrication and use, and good stability.

  • A magnetic stir bar sorbent of metal organic frameworks, carbon foam decorated zinc oxide and cryogel to enrich and extract parabens and bisphenols from food samples
    • Sirintorn Jullakan
    • Natnaree Rattanakunsong
    • Justyna Płotka-Wasylka
    • Opas Bunkoed
    2024 JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES

    A porous composite magnetic stir bar adsorbent was fabricated for the extraction and enrichment of parabens and bisphenols from selected beverage samples. The adsorbent comprised a metal organic framework, carbon foam decorated zinc oxide and magnetic nanoparticles embedded in polyvinyl alcohol cryogel. The porous composite stir bar adsorbent could adsorb parabens and bisphenols via hydrogen bonding, π-π and hydrophobic interactions. In the best conditions, linearity was good from 5.0 to 200.0 µg/L for methyl paraben, ethyl paraben and bisphenol A and from 10.0 to 200.0 µg/L for bisphenol B and butyl paraben. Limits of detection ranged from 1.5 to 3.0 µg/L. The developed composite stir bar was successfully applied to extract and determine parabens and bisphenols in fruit juice, beer and milk. Recoveries ranged from 89.5 to 99.5 % with RSDs lower than 6 %. The developed sorbent and new methodology were evaluated in terms of its green character with satisfactory results.

  • A Mammography Data Management Application for Federated Learning
    • Dmytro Tkachenko
    • Magdalena Mazur-Milecka
    2024

    This study aimed to develop and assess an application designed to enhance the management of a local client database consisting of mammographic images with a focus on ensuring that images are suitably and uniformly prepared for federated learning applications. The application supports a comprehensive approach, starting with a versatile image-loading function that supports DICOM files from various medical imaging devices and settings. It also aims to standardize the labeling and pre-processing of new images, statistical analysis and data visualization of mammographic images across all participating healthcare units. Initial image preprocessing is significantly enhanced through the use of Wiener and CLAHE filters, aimed at reducing noise and improving contrast, respectively, to ensure the highest quality of images for diagnostic purposes. Further refinement in the preprocessing pipeline is achieved with a U-Net model, trained on publicly available databases, which excels in segmenting the breast tissue from images, thereby eliminating irrelevant background and artifacts. This meticulous preparation of images not only standardizes data quality across multiple medical institutions but also facilitates collaborative model training within federated learning frameworks. The program allows for the review of images and their metadata, enables labeling of images with the ability to mark regions of interest (ROI), and utilize a pre-trained model for preliminary BI-RADS classification. A notable addition to the application is the integration of functionalities, thanks to the implementation of Grad-CAM model, designed to elucidate the decision-making processes of deep learning models. This integration further enriches the application's utility in supporting diagnostic and analytical tasks in mammography, providing clear insights into the interpretive reasoning behind model predictions.

  • A method to synthesise groove cam Geneva mechanisms with increased dwell period
    • Viacheslav Pasika
    • Pavlo Nosko
    • Oleksii Nosko
    • Oleksandr Bashta
    • Volodymyr Heletiy
    • Volodymyr Melnyk
    2024 Pełny tekst PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE

    The present study develops a method to synthesise the groove cam Geneva mechanism with increased dwell period. The main condition of the synthesis is to provide the desired law of motion of the wheel. Additional synthesis conditions are the limitation of the maximum pressure angle and the limitation of the minimum curvature radius of the cam profile. Unlike the conventional Geneva mechanisms, the synthesised groove cam Geneva mechanisms enable motion of the wheel due to an arbitrarily specified law, double locking of the wheel at its dwell-to-motion and motion-to-dwell transitions, absence of soft impacts in the extreme positions. The analysis shows that for the cycloidal law of motion, number of slots in range 3 to 15 and additional dwell coefficient in range 0 to 0.7, the operating time coefficient can be provided in wide range from 0.053 to 0.765. The effectiveness of the method is illustrated by numerical examples.

  • A methodology for ultimate strength assessment of ship hull girder accounting for enhanced corrosion degradation modelling
    • Krzysztof Wołoszyk
    • Floris Goerlandt
    • Jakub Montewka
    2024 MARINE STRUCTURES

    The presented work shows a methodology for the ultimate strength assessment of a ship hull, considering enhanced corrosion modelling. The approach is based on the classical Smith method. However, the recent findings regarding the impact of corrosion degradation on ultimate strength are incorporated. To this end, the stress–strain relationships for particular elements composing ship hull cross-section are modified using a specially developed correction factor. The proposed approach is validated with experimental results of the corroded box girders available in the literature, showing very good agreement. Further, a case study of a VLCC tanker ship is presented, and a comparison between contemporary and enhanced corrosion degradation modelling in terms of resulting ultimate strength is presented. The results indicate that the currently used method may significantly overestimate the hull’s structure capacity, especially considering the long exploitation period. Thus, current approaches lead to a non-conservative assessment of the ship hull girder’s ultimate strength, potentially increasing the risk of failure. It is therefore recommended to further investigate the proposed method, especially in the context of risk-based ship design approaches and holistic maritime transportation risk management.

  • A model for agribusiness supply chain risk management using fuzzy logic. Case study: Grain route from Ukraine to Poland
    • Ievgen Medvediev
    • Dmitriy Muzylyov
    • Jakub Montewka
    2024 Pełny tekst TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANSPORTATION REVIEW

    In order to establish new logistics routes, it is necessary to address several technical and organizational issues, among others. One of the most important criteria for evaluating the performance of a supply chain is the delivery time, proactive consideration of potential hazards and associated uncertainties that may occur along the route. However, the existing solutions are often passive and reactive, based on statistics, thus not leaving much room for proactive risk mitigation measures. Therefore, there is a need for a foreseeing modern approach to account for the impact of anticipated hazards on delivery time. The aim of this study is to develop a model for determining delivery time considering expected risk factors (RF), based on mathematical tools of fuzzy logic and actual background knowledge elicited from the literature and experts. The paper identifies primary technical and operational hazards that occur during loading and transport and converts them into risk factors. The risk factors are then quantified and fed into a fuzzy model developed with the Matlab Fuzzy Logic Toolbox and assembled in the Simulink environment. The application of the model is demonstrated in three case studies reflecting three potential grain supply chains (SC) from Ukraine to Poland: classical transport by rail grain hoppers (SC1); transport by containers on railway platforms (SC2); transport by bulk grain trucks (SC3). The resulting travel time for the analysed SCs is between 49 and 71 hours for SC1, between 45 and 62 hours for SC2 and between 42 and 62 hours for SC3. In addition, the outliers of the travel time values beyond the 1.5 quantiles were defined according to the uncertainty band. The results of the fuzzy model were compared with the results of the deterministic approach in the concurrent validation and a good agreement was found. This proves the appropriateness of the fuzzy model calculations and the possibility of using alternative SCs in grain delivery. The main benefit of the proposed model is a new universal tool based on a holistic and active approach to risk assessment using fuzzy logic.

  • A multiparameter simulation-driven analysis of ship response when turning concerning a required number of irregular wave realizations
    • Przemysław Krata
    • Mateusz Gil
    • Tomasz Hinz
    • Paweł Kozioł
    2024 OCEAN ENGINEERING

    The growing implementation of Decision Support Systems on modern ships, digital-twin technology, and the introduction of autonomous vessels cause the marine industry to seek accurate modeling of vessel response. Despite the contemporary 6DOF models can be used to predict ship motions in irregular waves, the impact of their stochastic realization is usually neglected and remains under-investigated. Especially in the case of turning, differences arising from the stochastic representation of the waves may result in excessive ship motions or even stability failure during maneuver execution. Therefore, in this study, statistical distributions of maximum amplitudes of roll, pitch, and lateral acceleration calculated in two representative locations on board a passenger vessel were analyzed concerning stochastic wave realization and existing extremes. The research utilized 6DOF simulation data and numerous realizations of the irregular wave with random phases of its components. Furthermore, the required number of wave realizations allowing for capturing the actual ranges of ship response at an assumed confidence level has been determined and analyzed. Ultimately, the results were compared in the safety-critical cases concerning various wave and operational conditions. The outcome of this study may be found useful by all parties involved in developing maritime autonomous systems and modeling ship motions.

  • A multiparameter simulation-driven analysis of ship turning trajectory concerning a required number of irregular wave realizations
    • Mateusz Gil
    • Przemysław Krata
    • Paweł Kozioł
    • Tomasz Hinz
    2024 OCEAN ENGINEERING

    In times of progressive automation of the marine industry, accurate modeling of ship maneuvers is of utmost importance to all parties involved in maritime transportation. Despite the existence of modern collisionavoidance algorithms using 6DOF motion models to predict ship trajectories in waves, the impact of stochastic realization of irregular waves is usually neglected and remains under-investigated. Therefore, herein, this phenomenon and its impact were investigated in the case study of the passenger ship’s turning. To this end, statistical and spatiotemporal distributions of ship positions and corresponding trajectory parameters were analyzed. This was made using massive 6DOF simulation data with particular attention to the observed extremes. Additionally, the minimum number of wave realizations has been determined using different methods in various simulation scenarios and afterward compared concerning parameters’ impact and existing dependencies. The results indicate that for simulated scenarios, the required number of wave realizations should be at least 20, but in rough seas should be greater than 30. These values satisfy an acceptable and operationally reasonable error limit reaching 15% of the ship’s length overall. The obtained results may be of interest to autonomous ship developers, scholars, and marine industry representatives working on intelligent collision-avoidance solutions and ship maneuvering models.

  • A New Approach of Solidification Analysis in Modular Latent Thermal Energy Storage Unit Based on Image Processing
    • Rafał Andrzejczyk
    • Muhammad Saqib
    • Michał Rogowski
    2024 Pełny tekst APPLIED THERMAL ENGINEERING

    The solidification process of RT18HC in a cylindrical shell and tube storage unit has been studied using a new methodology based on image processing. The main idea of the algorithm is to label the region of solidification and use statistical functions to calculate the dimensions of the solidification front over time. Said analysis includes two methods. The first method is to measure the solid fraction changes during solidification. The novelty of this method, as compared to other literature findings, is that pre-processing and calculation process occurs automatically via a calculation algorithm. This method is used to calculate the solid fraction of RT18HC which is reported to be a bit fast at the beginning that 40 % of its volume solidified in 1000 s while the rest of the process is completed in almost 6500 s. The second method is used to measure and calculate the thickness of the solid front by using image processing. This method’s error is calculated to be less than 7% throughout the entire process. The second method also acts as an experimental database of front thickness to use in a novel, simplified, semi-theoretical model proposed to calculate the solid front thickness as a function of time in this paper. It is also worth presenting solution extended by a general definition of thermal resistance for a cylindrical partition. The above study will enable the development of an enhanced and optimized model for complex geometries based on image processing techniques in the future. It will also allow the investigation of both processes i.e. solidification and melting alongside other influencing parameters such as the geometry of the storage unit in future.

  • A new strategy for PET depolymerization: Application of bimetallic MOF-74 as a selective catalyst
    • Mateusz Baluk
    • Patrycja Jutrzenka Trzebiatowska
    • Aleksandra Pieczyńska
    • Damian Makowski
    • Malwina Kroczewska
    • Justyna Łuczak
    • Adriana Zaleska-Medynska
    2024 JOURNAL OF ENVIRONMENTAL MANAGEMENT

    Large-volume production of poly(ethylene terephthalate) (PET), especially in the form of bottles and food packaging containers, causes problems with polymer waste management. Waste PET could be recycled thermally, mechanically or chemically and the last method allows to obtain individual monomers, but most often it is carried out in the presence of homogeneous catalysts, that are difficult to separate and reuse. In view of this, this work reports for the first time, application of bimetallic MOF-74 – as heterogeneous catalyst - for depolymerization of PET with high monomer bishydroxyethyl terephthalate, BHET) recovery. The effect of type and amount of second metal in the MOF-74 (Mg/M) was systematically investigated. The results showed increased activity of MOF-74 (Mg/M) containing Co2+, Zn2+ and Mn2+ as a second metal, while the opposite correlation was observed for Cu2+ and Ni2+. It was found that the highest catalytic activity was demonstrated by the introduction of Mg–Mn into MOF-74 with ratio molar 1:1, which resulted in complete depolymerization of PET and 91.8% BHET yield within 4 h. Furthermore, the obtained catalyst showed good stability in 5 reaction cycles and allowed to achieve high-purity BHET, which was confirmed by HPLC analysis. The as-prepared MOF-74 (Mg/Mn) was easy to separate from the post-reaction mixture, clean and reuse in the next depolymerization reaction.

  • A note on the Morse homology for a class of functionals in Banach spaces involving the 2p-area functional
    • Luca Asselle
    • Maciej Starostka
    2024 NODEA-NONLINEAR DIFFERENTIAL EQUATIONS AND APPLICATIONS

    In this paper we show how to construct Morse homology for an explicit class of functionals involving the 2p-area functional. The natural domain of definition of such functionals is the Banach space W_0^{1,2p}(\Omega), where p > n/2 and \Omega \subet R^n is a bounded domain with sufficiently smooth boundary. As W_0^{1,2p}(\Omega) is not isomorphic to its dual space,critical points of such functionals cannot be non-degenerate in the usual sense, and hence in the construction of Morse homology we only require that the second differential at each critical point be injective. Our result upgrades, in the case p > n/2 , the results in Cingolani and Vannella (Ann Inst H Poincaré Anal Non Linéaire 2:271–292, 2003; Ann Mat Pura Appl 186:155–183, 2007), where critical groups for an analogous class of functionals are computed, and provides in this special case a positive answer to Smale’s suggestion that injectivity of the second differential should be enough for Morse theory

  • A Novel [4+2] Cycloaddition Reaction Involving Lawesson’s Reagent. Structure and Specific Fragmentations of a New Cyclic 1,2-Thiaphosphinane-4-one
    • Witold Przychodzeń
    • Barbara Kusznierewicz
    2024 PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS

    A crude morpholine enamine of acetone treated with Lawesson’s reagent unexpectedly yielded a six-membered thiaphosphinane-4-one. This compound is the first example of a new class of heterocycles. It has been proven that it is formed from 4-methyl-2-morpholino-1,3-pentadiene which is usually present in crude morpholine enamine batches. A mechanism of this regioselective reaction was postulated and a characteristic chair-like conformation of the product was examined in detail. Additionally, some unusual primary fragmentations of the product with the loss of H2S and isobutylene were observed for positive and negative ESI ionization mode, respectively.

  • A novel approach to enhance high optically active L-lactate production from food waste by landfill leachate
    • Wenjuan Zhang
    • Jiaxin Shi
    • Yue Li
    • Yonghong Ma
    • Aisha Khanzada
    • Hussein Al-Hazmi
    • Xianbao Xu
    • Xiang Li
    • Gamal K. Hassan
    • Gang Xue
    • Jacek Mąkinia
    2024 Pełny tekst JOURNAL OF ENVIRONMENTAL MANAGEMENT

    The recycling of food waste (FW) through anaerobic fermentation into lactic acid (LA), with two isomers L-LA and D-LA, aligns with the principles of a bio-based circular economy. However, FW fermentation is often limited by competing pathways, acidification inhibition, and trace metals deficiency. This study investigates the introduction of landfill leachate, containing buffering agents (ammonia) and trace metals, into FW fermentation. Various dosages of landfill leachate, ranging from 90 (LN-90) to 450 mg/L (LN-450) based on inclusive ammonia calculation, were employed. Results showed that LA production peaked at 43.65 ± 0.57 g COD/L in LN-180 on day 6, with a high optical activity of L-LA at 92.40 ± 1.15 %. Fermentation pathway analysis revealed that landfill leachate amendment enhances hydrolysis (as evidenced by increased activity of amylase, α-glucosidase, and protease) and glycolysis (resulting in enhanced utilization of carbohydrates and glucose). The inclusive ammonia in leachate plays a crucial role as a buffer, maintaining optimal pH conditions (5–7), thereby reducing volatile fatty acid production and thus intensifying LA orientations. The increased activity of L-lactate dehydrogenase (L-LA generation) and decreased NAD-independent lactate dehydrogenase (LA consumption) in properly dosed leachate further explained the high accumulation of L-LA. Dominance of lactic acid bacteria, including Streptococcus, Enterococcus, Klebsiella, Bifidobacterium, Bavariicoccus, and Lacticaseibacillus, accounted for 91.08% (LN-90), while inhibitory effects were observed in LN-450 (4.45%). Functional gene analysis further supported the enhanced glycolysis, L-lactate dehydrogenase, and nitrogen assimilation. Finally, a network analysis indicates a beneficial effect on the genus Enterococcus and Klebsiella by landfill leachate addition. This study demonstrates the efficiency of utilizing landfill leachate to enhance LA recycling from FW fermentation, aligning with the concept of circular economy by transforming waste into valuable resources.

  • A Novel Device and System for Fall Detection Under the Shower
    • Adam Bujnowski
    • Bartłomiej Rajzer
    • Aleksey Andrushevich
    • Artur Poliński
    • Mariusz Kaczmarek
    • Jerzy Wtorek
    2024

    In this paper, device construction and preliminary results for shower safety assistance are presented. The device allows monitoring of shower-taking persons without violating privacy and intimacy, while it has the ability to detect a persons entering and leaving the shower and detecting fall conditions. It allows better supervision of elders living independently at their locations.

  • A Novel Iterative Decoding for Iterated Codes Using Classical and Convolutional Neural Networks
    • Marek Blok
    • Bartosz Czaplewski
    2024

    Forward error correction is crucial for communication, enabling error rate or required SNR reduction. Longer codes improve correction ratio. Iterated codes offer a solution for constructing long codeswith a simple coder and decoder. However, a basic iterative code decoder cannot fully exploit the code’s potential, as some error patterns within its correction capacity remain uncorrected.We propose two neural network-assisted decoders: one based on a classical neural network, and the second employing a convolutional neural network. Based on conducted research, we proposed an iterative neural network-based decoder. The resulting decoder demonstrated significantly improved overall performance, exceeding that of the classical decoder, proving the efficient application of neural networks in iterative code decoding.

  • A Numerical Model Study on Grasse River Ice Control Structures
    • Tomasz Kolerski
    • Hung Tao Shen
    2024 Pełny tekst CANADIAN JOURNAL OF CIVIL ENGINEERING

    Ice jams in the Grasse River have caused the erosion of capping material designed to prevent the resurfacing of the bed sediment in the PCB-contaminated area. Two in-stream ice-control structures are proposed to avoid the jam-induced erosion of the capping material. These two ice-control options are a pier-type ice-control structure and a reconstruction of a small hydropower dam upstream of the capping site. A numerical model study using the DynaRICE model is conducted to evaluate the effectiveness of the proposed design. Flow and ice conditions corresponding to the 100-year return period of ice jam events obtained from analyzing historical breakup ice jam data are used in the evaluation. The results showed that these ice-control structures could reduce the ice discharge downstream and the size of the ice jam at the capping site to prevent the erosion and scour of the PCB-contaminated bed.

  • A palatal prosthesis from archaeological research in the St Francis of Assisi church in Cracow (Poland)
    • Anna E. Spinek
    • Marta Kurek
    • Krzysztof Demidziuk
    • Marcin Nowak
    • Magdalena Śliwka-Kaszyńska
    • Anna Drążkowska
    2024 Journal of Archaeological Science-Reports

    The hard palate is a septum that not only prevents food from entering between the oral and nasal cavity, but also plays an important role during breathing or speech. The presence of cavities within it negatively affects the comfort of life of people with this type of impairment. Hence, in the literature one can find examples of the use of hard palate prostheses to restore the separation between the nasal and oral cavity. During archaeological research conducted in 2017–18 in the church of St Francis of Assisi in Cracow, the remains of a man with a cleft palate, who died at the age of about 50, were found. His burial is dated to the eighteenth century. Within his mouth, the presence of a palatal prosthesis was noted. This is the first case in Poland of finding an individual with an obturator tailored to its needs. The aim of the work is to present the structure and elemental composition of the found prosthesis and comparisons to the other obturators known from written sources. Macroscopic analysis showed the presence of an elliptical-shaped metal diaphragm and a textile “tampon” entering nasal cavity. The metal part of the prosthesis was made of copper alloy, covered with a layer of silver and gold. The comparison of the analysed obturator with examples from the literature indicates its great similarity to those used in the sixteenth and eighteenth centuries.

  • A Planar-Structured Circularly Polarized Single-Layer MIMO Antenna for Wideband Millimetre-Wave Applications
    • Ubaid Ullah
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Shahanawaz Kamal
    2024 Pełny tekst Engineering Science and Technology-An International Journal-JESTECH

    In this paper, a simple geometry, planar-structured printed multiple-input-multiple-output (MIMO) antenna utilizing dual circular polarization (CP) is presented. The proposed numerically and experimentally validated design features a fully grounded coplanar waveguide (CPW) and a systematically perturbed feedline radiator. The fringing electric (E) field along the feedline is altered by extruding periodic stubs on each side of the microstrip line extended from a grounded CPW. The different physical size of the stubs on each side, plus a slight offset introduced between the stubs breaks the symmetry of the vector E-fields on both side of the edges. The asymmetric E-field weakens the intensity of the respective magnetic current on the opposite side for a wider spectrum, resulting in a wideband operation. The asymmetric vertical magnetic current along the length of the stubs and the combined current on the horizontal edges yield 90-degree out-of-phase orthogonal field components, radiating circularly polarized waves. The proposed design has the advantage of topological simplicity and ease of polarization sense alteration. Owing to this, the design is implemented in MIMO configuration with each port radiating a different sense of CP. The antenna's simulated and measured -10 dB impedance bandwidth is more than 26.5% ranging from 24.6 GHz to 32.1 GHz frequency. Additionally, the antenna retains an axial ratio (AR) of 3 dB or less from 26 GHz to 31.8 GHz. The peak realized gain (RG) of the antenna is 10.3 dBic with an average value of ~ 9.5 dBic across the bandwidth confirming stable radiation in the broadside direction. At the same time, the envelop correlation coefficient and the diversity gain are about 0.01 and 10 dB, respectively over the operating band.

  • A probabilistic-driven framework for enhanced corrosion estimation of ship structural components
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    2024 Pełny tekst RELIABILITY ENGINEERING & SYSTEM SAFETY

    The work proposes a probabilistic-driven framework for enhanced corrosion estimation of ship structural components using Bayesian inference and limited measurement data. The new approach for modelling measurement uncertainty is proposed based on the results of previous corrosion tests that incorporate the non-uniform character of the corroded surface of structural components. The proposed framework's basic features are outlined, and the detailed algorithm is presented. Further, the proposed framework is validated by comparison with the classical statistical approach and mass measurements, considering previous experimental work results. Notably, the impact of the number of measuring points is investigated, and the accuracy index is proposed to identify the optimum number of measurements. The developed framework has a significant advantage over the classical approach since measuring uncertainty is incorporated. Additionally, the confidence intervals of both mean value corrosion depth and standard deviation could be gathered due to the probabilistic character of the framework. Thus, the presented approach can potentially be used in the structural health monitoring of ship structural components and reliability analysis.

  • A procedure for the identification of effective mechanical parameters of additively manufactured elements using integrated ultrasonic bulk and guided waves
    • Erwin Wojtczak
    • Magdalena Rucka
    • Angela Andrzejewska
    2024 MEASUREMENT

    The subject of the current work was a simple but robust novel two-stage procedure for the non-destructive determination of effective elastic constants using ultrasonic wave propagation. First, ultrasonic bulk wave velocities measured on cubic samples were used to calculate most of the elements of the stiffness matrix. Secondly, the remaining elements were determined using the dispersion curves of elastic guided waves measured on plate samples. Based on the complete stiffness matrix it was possible to calculate the complete set of effective elastic constants. The algorithm was verified for AM elements produced from PLA filament satisfying the conditions of transversely isotropic and orthotropic material models. For the transversely isotropic samples, Young’s moduli (E) varied from 2.6 to 2.9 GPa, shear moduli (G) equalled between 0.9 and 1.2 GPa, whereas Poisson’s ratios (ν) ranged between 0.20 and 0.32. In orthotropic sample the corresponding values were: E = 1.3–2.8 GPa, G = 0.6–1.2 GPa, and ν = 0.07–0.59. The results of the current study have been compared with references from the literature, giving satisfactory agreement.

  • A procedure for the visualization of fingerprint traces on standard and thermal paper using the electron excitation energy of 1,8-diazafluoren-9- one aggregates in a polyvinylpyrrolidone polymer
    • Aneta Lewkowicz
    • Martyna Czarnomska
    • Emilia Gruszczyńska
    • Katarzyna Karpienko
    • Maciej Wróbel
    • Michalina Chabowska
    • Piotr Bojarski
    2024 Pełny tekst Z Zagadnień Nauk Sądowych

    The scope of this study is a new procedure for visualizing dactyloscopic traces on an absorbent surface using a solution based on aggregates of 1,8-diazafluoren-9-one (DFO) in a polyvinylpyrrolidone polymer (PVP). An absorbent surface is defined as a plain or thermal paper, which is considered to be a difficult surface due to its varying chemical composition. In the case of the thermal paper surface, the procedure can be further improved by the addition of Au/Ag nanoparticles, which cause an enhancement of the fluorescence phenomenon from the surface of the fingerprint. The procedure requires the use of forensic illuminators and filters to reveal traces at the crime scene. Regarding the visualization of fingerprint prints in the forensic laboratory, the use of a stereo fluorescence microscope provides higher-resolution images when analyzing single patterns in the form of minutiae. The presented procedure is competitive with known, highly toxic current methods for revealing dactyloscopic traces using the DFO molecule. It also represents a key contribution to the development of methods for visualizing traces on thermal paper using fluorescent dyes and suitable control of their spectroscopic properties.

  • A prototype information system for managing and pricing e-waste
    • Krystian Jandy
    • Paweł Weichbroth
    2024 Pełny tekst

    There is no doubt that innovation drives development in all areas of human activity, including electrical and electronic equipment. However, the production of new equipment has a significant impact on the natural environment and a relatively high consumption of natural resources. To address these issues, the circular economy has been implemented in recent years by promoting and introducing numerous measures to facilitate the recycling of used goods. However, it has been found that there are many obstacles and difficulties currently faced by decision and policy makers. In this paper, we try to fill the research gap by presenting the prototype of an information system (IS) that could help not only these stakeholders, but also other interested parties, to move towards a circular economy through the efficient management of used electrical and electronic equipment (e-waste). In this context, we present the prototype of the system and elaborate on its two main components, namely functionality and user interface. Furthermore, we discuss the future research directions regarding the development of existing and new system features, followed by a comprehensive usability testing.

  • A random field-based simulational identification of possible levels of material imperfections of adhesive-bonded joints
    • Karol Winkelmann
    • Faizullah Jan
    • Łukasz Smakosz
    • Violetta Konopińska-Zmysłowska
    • Victor Eremeyev
    • Marcin Kujawa
    2024 Bulletin of the Polish Academy of Sciences-Technical Sciences

    Recently, structural adhesives have become significant in the shaping of structural elements, especially in thin-walled structures, where they replace or supplement traditional connection methods. However, adhesive-bonded joints are highly susceptible to internal structural imperfections due to their application technique and the nature of the adhesive. These material inconsistencies impact the strength parameters and the mechanical behavior of the entire connection. This study proposes a simplified method for the probabilistic numerical modeling of structural imperfections in an adhesive layer. The adhesive is modeled as an uncorrelated random field with weakened elements representing structural imperfections randomly scattered throughout its entire volume. The percentage of these imperfections (in relation to the total volume) is adopted a random variable.By conducting experimental tests on dogbone specimens of a selected adhesive and comparing them to adequate numerical tests with varying volumes of weakened elements, the determination of the representative imperfection volume of the investigated adhesive was possible. Based on these tests, the calibration of the probability density function to describe the volume of the imperfections may be performed. Furthermore, the application of the random model for an adhesive-bonded single lap-joint is shown to be viable. Finally, the calculation of a probability-based mechanical response (in this case, the normal force at critical elongation) of the single lap-joint with structural imperfections is performed, and its resultant reliability is assessed and evaluated.

  • A Residential Building Extension Prototype to face Post-Pandemic Needs: Foreseen Challenges and Impacts
    • Anna Stefańska
    • Carlos C. Duarte
    • Katarzyna Zielonko-Jung
    • Nuno D. Cortiços
    • Daniel Mateus
    2024 Green Energy & Environment

    The COVID-19 pandemic highlighted the importance of outdoor spaces for maintaining physical and mental well-being. However, many urban residents lack private outdoor areas, which led to harmful health consequences during lockdowns. The research project aims to address and solve this issue by developing a physical/digital prototype called “X-TEND” that extends living space outdoors by attaching it to existing multi-story residential building facades. This prototype intends to promote healthier lifestyles, improving the well-being of individuals and positively impacts the urban surroundings aesthetics. X-TEND prototype uses a light, modular, and prefabricated approach for cost-effectiveness and environmental sustainability. It incorporates generative processes for structural and bioclimatic optimisation complemented by green building strategies to reduce environmental impact while maximising thermal and energy performance. Ultimately, X-TEND prototype contributes to a more sustainable built environment, fostering healthier and more liveable cities for current and future generations.

  • A review of explainable fashion compatibility modeling methods
    • Karolina Selwon
    • Julian Szymański
    2024 ACM COMPUTING SURVEYS

    The paper reviews methods used in the fashion compatibility recommendation domain. We select methods based on reproducibility, explainability, and novelty aspects and then organize them chronologically and thematically. We presented general characteristics of publicly available datasets that are related to the fashion compatibility recommendation task. Finally, we analyzed the representation bias of datasets, fashion-based algorithms’ sustainability, and explainable model assessment. The paper describes practical problem explanations, methodologies, and published datasets that may serve as an inspiration for further research. The proposed structure of the survey organizes knowledge in the fashion recommendation domain and will be beneficial for those who want to learn the topic from scratch, expand their knowledge, or find a new field for research. Furthermore, the information included in this paper could contribute to developing an effective and ethical fashion-based recommendation system.

  • A Review of Recent Advances in Human-Motion Energy Harvesting Nanogenerators, Self-Powering Smart Sensors and Self-Charging Electronics
    • Justyna Gołąbek
    • Michał Strankowski
    2024 Pełny tekst SENSORS

    In recent years, portable and wearable personal electronic devices have rapidly developed with increasing mass production and rising energy consumption, creating an energy crisis. Using batteries and supercapacitors with limited lifespans and environmental hazards drives the need to find new, environmentally friendly, and renewable sources. One idea is to harness the energy of human motion and convert it into electrical energy using energy harvesting devices—piezoelectric nanogenerators (PENGs), triboelectric nanogenerators (TENGs) and hybrids. They are characterized by a wide variety of features, such as lightness, flexibility, low cost, richness of materials, and many more. These devices offer the opportunity to use new technologies such as IoT, AI or HMI and create smart self-powered sensors, actuators, and self-powered implantable/wearable devices. This review focuses on recent examples of PENGs, TENGs and hybrid devices for wearable and implantable self-powered systems. The basic mechanisms of operation, micro/nano-scale material selection and manufacturing processes of selected examples are discussed. Current challenges and the outlook for the future of the nanogenerators are also discussed.

  • A review on analytical models of brushless permanent magnet machines
    • Ahmed Abbas
    • Atif Iqbal
    • Arkadiusz Lewicki
    • Reddy B. Prathap
    • M Mnzool
    2024 Pełny tekst INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS

    This study provides an in-depth investigation of the use of analytical and numerical methods in analyzing electrical machines. Although numerical models such as the finite-element method (FEM) can handle complex geometries and saturation effects, they have significant computational burdens, are time-consuming, and are inflexible when it comes to changing machine geometries or input values. Analytical models based on magnetic equivalent circuits (MEC) or solving Maxwell's equations can be faster and more flexible, but less accurate for complex machine structures. The paper focuses on the recent development of analytical models for brushless permanent-magnet (PM) machines that have become increasingly popular in low and medium- power applications. The literature review covers the recent developments in analytical models for PM machines with respect to various machine quantities such as magnetic flux density components, induced voltage, inductances, electromagnetic force/torque, efficiency, or unbalanced magnetic force (UMF). It outlines the advantages and disadvantages of different analytical models such as the zero-dimensional (0-D), one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) analytical methods, as well as the Maxwell and basic mathematical analysis. Although the MEC models are faster than the numerical model, they are not as accurate for various structures of electrical machines including a great magnetic air gap. They also note that the analytical models based on the Maxwell equations are faster than the numerical ones and have the potential to obtain acceptable accuracy similar to the numerical models in electrical machines. Overall, this literature review provides valuable insights for researchers and engineers in selecting appropriate analytical models for PM machines. It highlights the trade-offs between accuracy and computational efficiency when choosing between numerical and analytical models, and the flexibility of analytical models to address changes in machine geometries or input values. Additionally, this helps researchers save time in determining appropriate references regarding the analytical models of brushless PM machines.