Publications Repository - Gdańsk University of Technology

Page settings

polski
Publications Repository
Gdańsk University of Technology

Show publications from the year

Recent items

  • Revisiting Supervision for Continual Representation Learning
    • Daniel Marczak
    • Sebastian Cygert
    • Tomasz Trzciński
    • Bartłomiej Twardowski
    2024

    "In the field of continual learning, models are designed to learn tasks one after the other. While most research has centered on supervised continual learning, there is a growing interest in unsupervised continual learning, which makes use of the vast amounts of unlabeled data. Recent studies have highlighted the strengths of unsupervised methods, particularly self-supervised learning, in providing robust representations. The improved transferability of those representations built with self-supervised methods is often associated with the role played by the multi-layer perceptron projector. In this work, we depart from this observation and reexamine the role of supervision in continual representation learning. We reckon that additional information, such as human annotations, should not deteriorate the quality of representations. Our findings show that supervised models when enhanced with a multi-layer perceptron head, can outperform self-supervised models in continual representation learning. This highlights the importance of the multi-layer perceptron projector in shaping feature transferability across a sequence of tasks in continual learning. The code is available on github."

  • RF Input-Quasi-Reflectionless Dispersive-Delay Structures Based on Complementary-Diplexer Circuits
    • Maciej Jasiński
    • Adam Lamęcki
    • Roberto Gómez-García
    • Michał Mrozowski
    2024

    A class of RF dispersive-delay structures (DDSs) with input-quasi-reflectionless behavior is reported. It is based on the exploitation of complementary-diplexer circuit networks, in which the out-of-band RF-input-power echoes reflected by the main bandpass-filter-(BPF)-type channel are dissipated by the resistively-terminated auxiliary bandstop-filter-(BSF)-type channel. Specifically, it is shown that the influence of the absorptive auxiliary channel over the in-band transmission-phase response of the main channel can be compensated to obtain the desired transmission-phase profile in the overall RF device. Thus, a multi-functional RF component with co-integrated DDS, BPF, and low-RF-input-reflection capabilities can be designed. Optimization-based synthesis examples at the coupling-routing-diagram level of third-and fifth-order input-quasi-reflectionless BPF-based DDSs, for which the in-band group-delay pattern increases linearly with frequency, are presented. Moreover, for practical-validation purposes, a 2-GHz microstrip prototype is built and measured.

  • Rhodotorulic Acid and its Derivatives: Synthesis, Properties, and Applications
    • Joanna Stefaniak-Skorupa
    • Michał Nowak
    • Andrzej Skwarecki
    2024 CURRENT MEDICINAL CHEMISTRY

    Siderophores are low molecular weight compounds produced by microorganisms to scavenge iron in iron-deficient environments. Rhodotorulic acid (RA), a natural hydroxamate siderophore, plays a vital role in iron acquisition for fungi and bacteria. As the simplest natural hydroxamate siderophore, RA exhibits a high affinity for ferric ions, enabling it to form stable complexes that facilitate iron uptake and transport within microorganisms. Insights into RA derivatives reveal distinct biological effects and applications, with potential in various fields, from antioxidants to antifungals. Rhodotorulic acid and its derivatives show promise for novel therapies, plant protection strategies, and iron supplementation in agriculture. Understanding their properties could advance science and medicine with sustainable practices.

  • Risk Assessment at Unsignalized Intersections Based on Human-Road-Environment-Vehicle System Applying Fuzzy Logic
    • Ievgen Medvediev
    • Dmitriy Muzylyov
    • Vitalii Ivanov
    • Jakub Montewka
    • Justyna Trojanowska
    2024

    The constant increase in motorization level and traffic density increases risks due to dangerous situations for road participants. Therefore, assessing the accident level of road network elements has been an urgent task over the past decades. However, existing approaches mainly rely on traffic flow parameters and account for dynamic vehicle characteristics. The research aims to design a model accounting for uncertain factors (weather conditions and pedestrian wear color) that directly impact the accident rate. For this, the mathematical toolkit of fuzzy logic is used. The study presented in this paper has yielded a model for assessing accident risk at unsignalized intersections. This model, known as the Fuzzy Model, considers various factors such as human behavior, road conditions, environmental factors, and vehicle characteristics. The model proposes accounting for the factors included in the four subsystems (Human-Road-Environment-Vehicle) that determine the transport mega system. Fuzzy Logic MATLAB Toolbox was used for modeling, and the model was assembled using Simulink Environment tools. The simulation used a full-factor experiment 34 for four factors at three variation levels for each parameter. A set of accident risk factors was obtained for 81 conducted tests. Based on the modeling, a 3-level table of accident risk measurement was formed at unsignalized intersections depending on the pedestrian's clothing color, intersection equipment level (illumination), weather conditions, and vehicle speed. The study results are due to a novel accident risk system that can be used for operational measures to increase safety levels at an unsignalized intersection.

  • Risk Assessment Due To Customs Delays In Supply Chains By Fuzzy Logic
    • Ievgen Medvediev
    • Dmitriy Muzylyov
    • Jakub Montewka
    2024

    Due to violations of existing trade relations, cargo flows between the European Union and Ukraine have been redistributed. As a result, new supply chains have been created that have increased the tension on ground transport, including road and rail. Unfortunately, this has caused significant delays when crossing the border, which has led to a greater increase in the total delivery time of goods. Therefore, to plan for effective delivery, it is important to consider risks associated with increased border passing time. A detailed study of the challenge revealed that these risks are caused by various hazards, which are often fuzzy. To address these risks, a modern mathematical approach is required. Fuzzy logic has proven to be successful in dealing with such research questions. According to the above, this study aims to design a fuzzy model that proactively assesses the risks of customs delays caused by operational, technical, human, and political hazards when crossing borders. The study identified four categories of hazards that can lead to delays or refusals in customs operations, resulting in increased border crossing times. These hazards are technical failures of the control system, border blocking due to human factors, formation of a queue for technological failures, and political influence. The proposed approach can take into account both quantitative and non-quantitative threats arising at the border. The study resulted in a decision support system that allows carriers to calculate possible risks and select the best alternative border crossing point in advance, reducing the risk of supply chain disruptions due to customs waivers.

  • Risk factor assessment in agricultural supply chain by fuzzy logic
    • Dmitriy Muzylyov
    • Ievgen Medvediev
    • Olexiy Pavlenko
    2024

    Significant uncertainty characterizes the harvest period. This aspect is due to various risks impacting agrifood supply chains. The occurrence of risks is due to hazards: technological failures, technical breakdowns, or adverse weather conditions. Hence, the operational time of the agricultural supply chain during the harvest period increases due to such risk factors. In essence, some hazards are fuzzy, and the nature of most threats is characterized by significant uncertainty. Classical risk assessment methods do not allow assessing simultaneously the impact of various risks, especially those expressed fuzzy (weather conditions). Therefore, the study objective is to design a fuzzy model assessing risk factors that impact the increase in the operating time of the agrifood supply chain during the harvest period. As initial parameters in the indistinct model, three groups of risk factors were accepted: weather conditions, technological failures and technical malfunctions. The MATLAB Fuzzy Toolbox is used to design the fuzzy model, and the model architecture is implemented in Simulink. The modelling results can be used to create the necessary reserves of the harvesting and transport complex to ensure timely harvesting and reduce the negative impact of hazards on the agricultural supply chain operating.

  • Risks caused by microbiologically influenced corrosion in diesel fuel storage tanks
    • Michał Kuna
    • Andrzej Miszczyk
    2024 Ochrona przed Korozją

    Microbiologically influenced corrosion (MIC) poses serious problems for the petrochemical and refinery industries. Particularly favourable conditions for MIC arise in storage tanks and transmission pipelines for mixtures of diesel oil with the addition of a biocomponent (in Poland 7%). The best conditions for the development of MIC occur at the fuel-water interface, where microorganisms are provided with a source of food and water, the presence of which is one of the basic conditions for the development of microorganisms. The development of microbiological deposits leads to the formation of sludge, causing fuel deterioration and corrosion that occurs under the resulting biomass. Studies have shown that biodiesel, alone as a substitute and as an additive to traditional fuels, increases the corrosion rate of carbon steel used in pipelines, storage tanks and other fuel infrastructure. Therefore, there is an increasing demand for research on methods of protecting steel surfaces in these conditions. The phenomena causing the corrosion of tanks and directions of research related to the protection against corrosion of infrastructure will be discussed.

  • Robust asymptotic super twisting sliding mode observer for non-linear uncertain biochemical systems
    • Mateusz Czyżniewski
    • Rafał Łangowski
    2024 JOURNAL OF PROCESS CONTROL

    The problem of state estimation (reconstruction of the state vector) for a given class of biochemical systems under uncertain system dynamics has been addressed in this paper. In detail, the bioreactor at a water resource recovery facility represents the considered biochemical systems. The biochemical processes taking place in the bioreactor have been modelled using an activated sludge model. Based on this model, an appropriate utility model has been derived for estimation purposes. The internal dynamics of the model have been burdened with unstructured and parametric uncertainty due to the unknown reaction kinetics functions. Taking this uncertainty into account, an analysis of the observability and detectability of the utility model has been carried out. The utility model and the available set of inputs and measured outputs have been used to design a new robust non-linear observer that allows the estimation of state variables in the presence of uncertainty. In the synthesis of the observer, the asymptotic observer methodology has been combined with a second-order sliding mode observer, a so-called super twisting algorithm. The developed observer generates not only robust and stable estimates of the state variables but also enables the reconstruction of unknown kinetic functions. The stability of the designed observer has been proven using the Lyapunov stability theory. The observer has been implemented in the Matlab/Simulink environment. The comprehensive simulation studies carried out show the high efficiency of the estimation process using the developed state observer.

  • Rola zieleni w kształtowaniu tożsamości przestrzennej miasta na przykładzie Gdyni
    • Maura Zaworska
    2024

    Istnienie miast bez zieleni jest prawie niemożliwe, dlatego rola zieleni w kształtowaniu tożsamości przestrzennej miast była ważnym czynnikiem przy podejmowaniu prób tworzenia zieleni tam urządzonej. Sztuka kształtowania terenów zieleni w Gdyni obecna była od początku istnienia miasta, a nawet wcześniej. W pracy uporządkowano aparat pojęciowy związany z zagadnieniami architektury krajobrazu towarzyszącymi pojęciom tożsamości przestrzennej. Zebrano i usystematyzowano podstawowe definicje w oparciu o przegląd literatury naukowej i doświadczenia własne autorki. W kolejnych etapach pracy omówiono ewolucję koncepcji zieleni miejskiej oraz tendencje jej projektowania. Wykazano, że wraz ze wzrostem świadomości przemian cywilizacyjnych złożoność zagadnień przyrodniczych staje się domeną interdyscyplinarnych dyskursów nad rolą zieleni w kształtowaniu przyszłości życia w terenach zurbanizowanych. Od końca XIX wieku wyraźny jest wzrost świadomego udziału zieleni w kształtowaniu tożsamości przestrzennej miast. Wskazano, że zieleń komponowana w Gdyni towarzyszyła jej rozwojowi już w okresie przedmiejskim i była nieodłącznym elementem rozwoju miasta w okresie dwudziestolecia międzywojennego, następnie wojny i okresu powojennego aż do dziś. Na podstawie przeglądu literatury wskazano, że pamięć o przeszłości Gdyni stanowi istotny element w kształtowaniu jej tożsamości przestrzennej oraz że występuje silny związek terenów zieleni z kreowaniem tożsamości przestrzennej miasta. W różnych okresach rozwojowy miasta relacja ta przyjmuje odmienny charakter, bazując na innych komponentach przyrodniczych oraz ideowych....

  • Role of buttering layer composition on microstructural heterogeneity and mechanical properties of Alloy 617 and P92 steel dissimilar welded joints for future Indian AUSC program
    • Saurabh Rathore
    • Amit Kumar
    • Sachin Sirohi
    • Vivek Singh
    • Ankur Gupta
    • Dariusz Fydrych
    • Chandan Pandey
    2024 INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY

    Restrictive operating conditions (even exceeding 700 °C) of materials in advanced ultra super critical (AUSC) power plants and the need to minimize manufacturing and maintenance costs require the production of dissimilar metal welded joints (DMW). Significant differences in the physical and chemical properties of welded materials lead to phenomena that reduce the weldability of the metals used and force the search for solutions that limit unfavorable phenomena, e.g., the use of buttering layers. The study presents a comparison of two types of joints with Alloy 617 (UNS N06617) and ferritic P92 (UNS K92460) steel made using Inconel 82 (ENiCrFe-3) and Inconel 617 (ERNiCrCoMo-1) alloys buttering layer and the corresponding chemical composition of filler metals. All areas of the joints made with the gas tungsten arc welding process were subjected to structural investigations (optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) and mechanical tests (microhardness, room and high temperature tensile, and toughness testing). Despite the more complicated welding procedure, sound welded joints were obtained with favorable properties resulting, inter alia, from the reduced thickness of the martensite layer in HAZ of P92 steel and the limited diffusion of alloy components compared to welded joints without the buttering layer. This also resulted in a reduction of the maximum hardness (especially in the case of Inconel 82 buttering—by 15–30 HV0.5 in comparison with Inconel 617 buttering) and an increase in strength while limiting the decrease in plasticity (even 663 MPa tensile strength and 21% of elongation for Inconel 617 buttered joint). Moreover, improved high-temperature performance (approximately 70–100 MPa) of the welded joint following the application of the buttering layer was confirmed. The presented results allow for drawing general conclusions that both proposed welding procedures can be recommended for use in the working conditions occurring at AUSC.

  • Room vs. Body Temperature to Evaluate Electrical Interface Parameters of State-Of-The-Art PEDOT : PSS-Based Electrodes
    • Karolina Cysewska
    2024 ChemElectroChem

    In this work, the effect of the simulated body fluid temperature on the electrical interface parameters of the state-of-the-art PEDOT-PSS electrode was studied. PEDOT-PSS was synthesized by electrodeposition on graphite and gold-coated-graphite electrodes. All electrochemical measurements were performed in phosphate-buffered saline aqueous solution (pH 7.4) at room temperature (25 °C) and body temperature (37 °C). The results of the work confirmed that the modification of the carbon or metallic electrode with conducting polymer PEDOT : PSS significantly reduced the interfacial impedance and improved charge storage capacity and current injection limit due to its high electroactive surface area, roughness and porosity compared to the bare substrates. The work showed that solution temperature is a critical factor that can influence the electrical interface parameters of electrodes for neural stimulation. Understanding and controlling these temperature-dependent effects are essential for ensuring the reliability, safety, and efficacy of neural stimulation applications in both research and clinical settings.

  • Rotating rod and ball
    • Sergey Kryzhevich
    • Alexander Plakhov
    2024 JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS

    We consider a mechanical system consisting of an infinite rod (a straight line) and a ball (a massless point) on the plane. The rod rotates uniformly around one of its points. The ball is reflected elastically when colliding with the rod and moves freely between consecutive hits. A sliding motion along the rod is also allowed. We prove the existence and uniqueness of the motion with a given position and velocity at a certain time instant. We prove that only 5 kinds of motion are possible: a billiard motion; a sliding motion; a billiard motion followed by sliding; a sliding motion followed by a billiard one; and a constant motion when the ball is at the center of rotation. The asymptotic behaviors of time intervals between consecutive hits and of distances between the points of hits on the rod are determined.

  • Rotational stiffness of a connection made using a single prestressed bolt
    • Paweł Pieczka
    • Piotr Iwicki
    2024 Full text ENGINEERING STRUCTURES

    The often overlooked rotational stiffness of connections utilizing a single prestressed bolt leads to the common assumption of treating such connections as pinned or even modeling them as rigid. Nevertheless, considering the friction between interconnected elements, it is evident that the actual rotational stiffness lies between these simplified assumptions. This study is dedicated to quantifying this stiffness and addressing the question of whether simplifying such connections to pinned or rigid is justifiable. Experimental, theoretical, and numerical analyses were conducted. The results reveal a substantial variability in this phenomenon, which can be effectively described by a normal distribution. Illustrated through a case study involving built-up battened columns, it was demonstrated that the maximum normal force in the column, when considering rotational stiffness of connections, significantly surpasses that obtained for a model assuming pinned connections. This underscores the necessity of employing a model with nonlinear rotational stiffness for an accurate analysis of such constructions.

  • Rotor flux and EEMF observer for interior permanent magnet synchronous machine
    • Deepak Vyas
    • Marcin Morawiec
    • Daniel Wachowiak
    2024 Full text Bulletin of the Polish Academy of Sciences-Technical Sciences

    In recent years, the use of the interior permanent magnet synchronous machine (IPMSM) in various applications has grown significantly due to numerous benefits. Sensors are used to achieve high efficiency and good dynamic response in IPMSM drives but due to their high cost and reduced overall size of the system, sensorless control techniques are preferred. Non-sinusoidal distribution of rotor flux and slot harmonics are present in the considered IPMSM. In this article, these problems are considered control system disturbances. With the above-mentioned problems, the classical observer structure based on (d-q) fails to estimate at low-speed ranges. This article proposes an observer structure based on a rotor flux vector in (-) stationary reference frame, which works using the adaptive control law to estimate speed and position, and a non-adaptive EEMF-based observer to estimate speed and position. Moreover, a comparative analysis between both observer structures at different speed ranges is also considered in this article. The effectiveness of the observer structure is validated by simulation tests and experimental tests using the sensorless control system with a field-oriented control scheme for a 3.5 kW IPMSM drive system.

  • Roughness measurement results evaluation of 6082 aluminium alloy specimens after fatigue bending tests
    • Przemysław Podulka
    • Wojciech Macek
    • Robert Owsiński
    • Ricardo Branco
    • Jarosław Trembacz
    2024 PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISIONENGINEERING AND NANOTECHNOLOGY

    In this paper, the topography of 6082 aluminium alloy specimens after fatigue bending tests was studied with a comprehensive evaluation of measurement noise caused by vibration. Roughness results were acquired by contactless Focus Variation Microscopy (FVM). Studied data were pre-processed, removing the non-measured points and outliers with regular methods, respectively, and high-frequency noise was considered. The variations in ISO 25178 roughness parameters were studied. Based on the previous studies, it was found that surfaces after fatigue bending tests can be difficult to consider when analyzing the measurement noise in a selected bandwidth. Some advantages of profile data extraction in selected directions, like horizontal, vertical or crack, were found deficient, even in studies by various functions, like autocorrelation, power spectral density, or texture direction ratio. When noise suppression methods depend on the details studied, boundary areas were extracted to compare and highlight the presence of high-frequency data characteristics. The proposed method was validated when contrasting standardised Gaussian or median filtering techniques with the spline filtering approach. A proper filter for the reduction of vibrational noise from the results of FVM topography measurements was suggested based on the proposed procedure. Finally, it was proposed how use the new method for reducing errors caused by high-frequency measurement noise in the surface topography of specimens after fatigue bending tests.

  • Rozwój nowej generacji bezzałogowych pojazdów nawodnych i podwodnych z wykorzystaniem zaawansowanych technologii i osiągnięć w zakresie zastosowania systemów sterowania przez sztuczną inteligencję AI
    • Mirosław Gerigk
    • Mateusz Gerigk
    2024

    Ostatnia dekada to ciągła praca nad dalszym rozwojem i wdrażaniem bezzałogowych pojazdów morskich. Między nimi są autonomiczne pojazdy podwodne (ang. autonomous underwater vehicle - AUV) i bezzałogowe pojazdy nawodne (ang. unmanned surface vehicle - USV). Niektóre pojazdy USV mogą być typu WIG (ang. wing in ground, 'w ziemi'), co związane jest z wykorzystaniem efektu przypowierzchniowego występującego w czasie ruchu skrzydła w pobliżu powierzchni czy swobodnej powierzchni wody. Rośnie zainteresowanie opracowywaniem i wdrażaniem w pełni rozwiniętych implementacji bezzałogowych pojazdów morskich. Głównym motorem rozwoju takich pojazdów są technologie, takie jak innowacyjne formy kadłuba pojazdu, innowacyjne materiały konstrukcyjne, w tym nanomateriały i materiały ,,inteligentne", innowacyjne źródła zasilania w energię, układy napędowe łączące wydajne i ciche silniki i pędniki, technologie systemów autonomicznych, technologie systemów sensorycznych i efektorowych oraz innowacyjne technologie informatyczne, w tym zaawansowane systemy nawigacji, komunikacji i sterowania. Pomiędzy tymi technologiami ważną rolę do odegrania ma sztuczna inteligencja wykorzystywana przez zaawansowane systemy sterowania. Dodatkowy zestaw cech, jakie mogą posiadać morskie pojazdy bezzałogowe, oferują rozwiązania oparte na technologii stealth i biotechnologii.

  • Saint-Venant torsion based on strain gradient theory
    • Przemysław Podulka
    • Wojciech Macek
    2024 INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES

    In this study, the Saint-Venant torsion problem based on strain gradient theory is developed. A total form of Mindlin's strain gradient theory is used to acquire a general Saint-Venant torsion problem of micro-bars formulation. A new Finite Element formulation based on strain gradient elasticity theory is presented to solve the Saint-Venant torsion problem of micro-bars. Moreover, the problem is solved for both micro and macro scale. In addition, six different cross sections in solid and hollow condition are considered, which the Saint-Venant torsion problem is solved on them. Torsional response of micro-bars is predicted by using the modified couple stress theory and the strain gradient theory of Aifantis which both of them employ only one length scale parameter. Some micro-bars with different cross-sectional area are investigated to show the performance of current study and conclusions are drawn from the micron-scale torsional feedback for micro-bars.

  • Sampling-based novel heterogeneous multi-layer stacking ensemble method for telecom customer churn prediction
    • Fatima E. Usman-Hamza
    • Abdullateef O. Balogun
    • Ramoni Tirimisiyu Amosa
    • Luiz Fernando Capretz
    • Hammed Mojeed
    • Shakirat A. Salihu
    • Abimbola G. Akintola
    • Modinat Abolore Mabayoje
    2024 Full text Scientific African

    In recent times, customer churn has become one of the most significant issues in business-oriented sectors with telecommunication being no exception. Maintaining current customers is particularly valuable due to the high degree of rivalry among telecommunication companies and the costs of acquiring new ones. The early prediction of churned customers may help telecommunication companies to identify the causes of churn and design industrial tactics to address or mitigate the churn problem. Controlling customer churn by developing efficient and reliable customer churn prediction (CCP) solutions is essential to achieving this objective. Findings from existing CCP studies have shown that numerous methods, such as rule-based and machine-learning (ML) mechanisms, have been devised to solve the CCP problem. Nonetheless, the problems of adaptability and the resilience of rule-based CCP solutions are its major weaknesses, and the skewed pattern of churn datasets (class imbalance) is detrimental to the prediction performances of conventional ML models in CCP. Hence, this research developed a robust heterogeneous multi-layer stacking ensemble method (HMSE) for effective CCP. Specifically, in the HMSE method, the prediction prowess of five ML classifiers (Random Forest (RF), Bayesian network (BN), Support Vector Machine (SVM), K-Nearest Neighbour (KNN), and Repeated Incremental Pruning to Produce Error Reduction (RIPPER)) with distinct computational characteristics are ensembled based on stacking and the resulting model is further enhanced using a forest penalizing attribute (FPA) model. The synthetic minority oversampling technique (SMOTE) is integrated with the proposed HMSE to balance the skewed class label present in the original experimental datasets. Extensive tests were carried out to determine the effectiveness of the proposed HMSE and S-HMSE on standard telecom CCP datasets. Observed findings from the experimental results showed that HMSE and S-HMSE can effectively predict churners even with the class imbalance (skewed datasets) problem. In addition, comparison studies demonstrated that the suggested S-HMSE offered improved prediction performance and optimum solutions for CCP in the telecom sector in comparison with baseline classifiers, homogeneous ensemble methods, and current CCP approaches.

  • Scale transformations in model exchange potentials in low energy electron-atom scattering
    • Felipe Arretche
    • Eliton Popovicz Seidel
    • Wagner Tenfen
    2024 JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA

    Model exchange potentials are particularly interesting to account for the indistinguishability between the projectile and target electrons in electron-atom scattering in vacuo and plasma environments. It is well known that their performance is pretty satisfactory in the high energies but also that discrepancies from the results obtained with exact exchange are found toward the zero energy limit. In this article, we examine how well established model exchange potentials based on the free electron gas approach compare to phase shifts calculated considering exchange in exact form. In particular, we show that the Hara and the semiclassical exchange potentials are able to reproduce reference low energy phase shifts through a simple scale transformation, in opposition to the previous approaches where energy dependent corrections to the local momentum were adopted. We provide the scale factors and phase shifts for electron scattering by He, Ne and Ar atoms for < 1,0 a.u. Such scaling factors can be determined reproducing the scattering length and the number of s-wave bound states from exact exchange calculations. We also show that the scaling procedure works for electronic densities that present the physically correct asymptotic behavior. The present results are important to the research field, since they form the basis to construction of scattering models based on optical potential approaches.

  • Schemat powstawania rys na przykładzie osiowo rozciąganego pręta żelbetowego
    • Marek Wesołowski
    • Maciej Solarczyk
    2024 Full text Inżynieria i Budownictwo

    W artykule przedstawiono w sposób schematyczny ideę powstawania kolejnych rys w konstrukcjach żelbetowych na przykładzie osiowo rozciąganego pręta. Opisano początkowy oraz końcowy stan zarysowania. Wyprowadzono wzór na szerokość rysy. Przedstawiono interpretację geometryczną rys dla fazy początkowego zarysowania oraz efekt tension stiffening na przykładzie elementu osiowo rozciąganego. Przedstawiono przykładowe obliczenia miary efektu tension stiffening, szerokości rys oraz średnich naprężeń przyczepności dla fazy początkowych rys.

  • Schottky Junction-Driven Photocatalytic Effect in Boron-Doped Diamond-Graphene Core–Shell Nanoarchitectures: An sp3/sp2 Framework for Environmental Remediation
    • Surya Kanta Ghadei
    • Mateusz Ficek
    • Salila Kumar Sethy
    • Jacek Ryl
    • Mukul Gupta
    • Ramasamy Sakthivel
    • Kamatchi J Sankaran
    • Robert Bogdanowicz
    2024 ACS Applied Materials & Interfaces

    Self-formation of boron-doped diamond (BDD)-multilayer graphene (MLG) core–shell nanowalls (BDGNWs) via microwave plasma-enhanced chemical vapor deposition is systematically investigated. Here, the incorporation of nitrogen brings out the origin of MLG shells encapsulating the diamond core, resulting in unique sp3/sp2 hybridized frameworks. The evolution mechanism of the nanowall-like morphology with the BDD-MLG core–shell composition is elucidated through a variety of spectroscopic studies. The photocatalytic performance of these core–shell nanowalls is examined by the deterioration of methylene blue (MB) and rhodamine B (RhB) dyes beneath low-power ultraviolet (UV) light irradiation. Starting with 5 ppm dye solutions and employing BDGNWs as the photocatalyst, remarkable degradation efficiencies of 95% for MB within 100 min and 91% for RhB within 220 min are achieved. The effect of varying dye concentrations was also examined. The enhanced photocatalytic activity is driven by carrier photogeneration and mediated by the Schottky junction formed between BDD and MLG, promoting efficient photoinduced charge separation. The stability of the BDGNW photocatalyst is examined, and after five test runs, the photocatalytic behavior for MB and RhB degradation decreases to 87 and 85%, respectively, from initial values of 96 and 91%, demonstrating excellent photostability. These findings underscore the significance of diamond-graphene nanoarchitectures as promising green carbonaceous photocatalysts.

  • Screening evaluation of the quality of commercially available cigars, cigarillos, and bidis based on emission levels of selected terpenes and terpenoids
    • Mariusz Marć
    • Sylwia Bednarska
    • Paweł Hać
    • Piotr Konieczka
    2024 MICROCHEMICAL JOURNAL

    The aim of the research was to verify the use of the solvent-free, non-destructive and easy to operate analytical method to study and compare the emissions of 16 representatives of terpenes and terpenoids from commercially available cigars, cigarillos and bidis − a potential screening analysis for the quality of combustible tobacco products. To assess the amount of organic compounds emitted to the gaseous phase from investigated tobacco samples, the stationary emission chambers system (at the sample conditioning stage) and gas chromatography with flame ionization detector (at the final analyte determination stage) were used. Studied samples represented five origins: the Dominican Republic, Nicaragua, Mexico, Cuba, and India and two manufacture approaches: machine-made and handmade. The assessed values of total volatile organic compounds (TVOCs) was from 0.58 to 28 µg·g−1 (at 60 °C) and from 26 to 430 µg·g−1 (at 120 °C). For Dominican products, Camphene and α-Cedrene were characterized by the highest emission level (233 ± 34 ng·g−1 and (3.7 ± 1.4) × 102 ng·g−1, respectively). In a case of Mexican and Cuban products it was noticed that the emission level of determined terpenes and terpenoids is higher in the case of hand-rolled tobacco products than mechanically manufactured ones. In a case of Nicaraguan hand-rolled products, Camphene, L-(−)-Fenchone, and α-Cedrene were characterized by the highest emission rate at 120 °C (213 ± 81 ng·g−1, 191 ± 45 ng·g−1 and 213 ± 84 ng·g−1, respectively). The highest emission level for Indian products in 120 °C was observed for α-Cedrene and Geranyl Acetate – respectively 181.6 ± 4.4 ng·g−1 and 101 ± 13 ng·g−1. The results of this study may indicate that sometimes cheaper products such as cigarillo have an emission profile that classifies them between expensive products such as “large cigars.”

  • Screening of perfluoroalkyl substances and their environmental impact in sequencing batch reactors combined with nature-based solutions
    • Grażyna Gałęzowska
    • Katarzyna Kołecka
    • Monika Cieszyńska-Semenowicz
    • Vladyslaw Redko
    • Magdalena Gajewska
    2024 Full text ECOLOGICAL ENGINEERING

    Perfluoroalkyl substances (PFAS) are a growing problem in the environment. The research indicates that they are present in surface water, groundwater, drinking water sources, wastewater treatment plant (WWTP) effluents, and landfill leachates. Additionally, the conventional methods of wastewater treatment are ineffective in their removal. This study aimed to indicate the concentration of PFAS in wastewater during treatment processes in sequential biological reactors (SBRs), followed by two ponds working in series. Samples were collected after individual stages of treatment, during the beginning of touristic seasonality. The research also determined the environmental impact of the PFAS by determining the ecotoxicity and performing a risk assessment of the analyzed wastewater. The analyzed wastewater samples were collected from the different stages of the WWTP in Swarzewo, which uses SBRs. In the collected samples, basic parameters such as total suspended solids (TSS), biological oxygen demand (BOD5), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), as well as identification and concentrations of PFAS were determined. Based on this data, an ecotoxicological assessment and risk assessment of the wastewater was performed. The research indicated that the basic parameters and Microtox toxicity assay are not sensitive to changes in the PFAS content in wastewater. As the hydrophobicity of the PFAS increases, their solubility in the water decreases. However, these substances may still be present in suspended particles, leading to an increase in their global concentration in the water and, consequently, may pose environmental hazards. The proposed technology of wastewater treatment is an effective PFAS retention system in the sediment (removal of over 90 %). Meteorological conditions affect the PFAS transformation processes taking place in SBRs.

  • Screening stability, thermochemistry, and chemical kinetics of 3-hydroxybutanoic acid as a bifunctional biodiesel additive
    • Mohamed A. Abdel-Rahman
    • Abolfazl Shiroudi
    • Jacek Czub
    • Hao Zhao
    2024 Full text JOURNAL OF PHYSICAL CHEMISTRY A

    The thermo-kinetic aspects of 3-hydroxybutyric acid (3-HBA) pyrolysis in the gas phase were investigated using density functional theory (DFT), specifically the M06-2X theoretical level in conjunction with the cc-pVTZ basis set. The obtained data were compared with benchmark CBS-QB3 results. The degradation mechanism was divided into 16 pathways, comprising 6 complex fissions and 10 barrierless reactions. Energy profiles were calculated and supplemented with computations of rate coefficients and branching ratios over the temperature range of 600–1700 K at a pressure of 1 bar using transition state theory (TST) and Rice–Ramsperger–Kassel–Marcus (RRKM) methods. Thermodynamics results indicated the presence of six stable conformers within a 4 kcal mol–1 energy range. The estimated chemical kinetics results suggested that TST and RRKM approaches are comparable, providing confidence in our calculations. The branching ratio analysis reveals that the dehydration reaction pathway leading to the formation of H2O and CH3CH═CHCO2H dominates entirely at T ≤ 650 K. At these temperatures, there is a minor contribution from the simple homolytic bond fission reaction, yielding related radicals [CH3•CHOH + •CH2CO2H]. However, at T ≥ 700 K, this reaction becomes the primary decomposition route. At T = 1700 K, there is a minor involvement of a reaction pathway resulting in the formation of CH3CH(OH)•CH2 + •CHO(OH) with an approximate contribution of 16%, and a reaction leading to [•CH3 + •CH2OHCH2CO2H] with around 9%.

  • Segmentation-Based BI-RADS ensemble classification of breast tumours in ultrasound images
    • Maciej Bobowicz
    • Mikołaj Badocha
    • Katarzyna Gwozdziewicz
    • Marlena Rygusik
    • Paulina Kalinowska
    • Edyta Szurowska
    • Tomasz Dziubich
    2024 Full text INTERNATIONAL JOURNAL OF MEDICAL INFORMATICS

    Background: The development of computer-aided diagnosis systems in breast cancer imaging is exponential. Since 2016, 81 papers have described the automated segmentation of breast lesions in ultrasound images using arti- ficial intelligence. However, only two papers have dealt with complex BI-RADS classifications. Purpose: This study addresses the automatic classification of breast lesions into binary classes (benign vs. ma- lignant) and multiple BI-RADS classes based on a single ultrasonographic image. Achieving this task should reduce the subjectivity of an individual operator’s assessment. Materials and Methods: Automatic image segmentation methods (PraNet, CaraNet and FCBFormer) adapted to the specific segmentation task were investigated using the U-Net model as a reference. A new classification method was developed using an ensemble of selected segmentation approaches. All experiments were performed on publicly available BUS B, OASBUD, BUSI and private datasets. Results: FCBFormer achieved the best outcomes for the segmentation task with intersection over union metric values of 0.81, 0.80 and 0.73 and Dice values of 0.89, 0.87 and 0.82, respectively, for the BUS B, BUSI and OASBUD datasets. Through a series of experiments, we determined that adding an extra 30-pixel margin to the segmentation mask counteracts the potential errors introduced by the segmentation algorithm. An assembly of the full image classifier, bounding box classifier and masked image classifier was the most accurate for binary classification and had the best accuracy (ACC; 0.908), F1 (0.846) and area under the receiver operating char- acteristics curve (AUROC; 0.871) in the BUS B and ACC (0.982), F1 (0.984) and AUROC (0.998) in the UCC BUS datasets, outperforming each classifier used separately. It was also the most effective for BI-RADS classification, with ACC of 0.953, F1 of 0.920 and AUROC of 0.986 in UCC BUS. Hard voting was the most effective method for dichotomous classification. For the multi-class BI-RADS classification, the soft voting approach was employed. Conclusions: The proposed new classification approach with an ensemble of segmentation and classification approaches proved more accurate than most published results for binary and multi-class BI-RADS classifications.

  • Seismic probabilistic assessment of steel and reinforced concrete structures including earthquake-induced pounding
    • Farzin Kazemi
    • Neda Asgarkhani
    • Ahmed Manguri
    • Robert Jankowski
    2024 Full text Archives of Civil and Mechanical Engineering

    Recent earthquakes demonstrate that prioritizing the retrofitting of buildings should be of the utmost importance for enhancing the seismic resilience and structural integrity of urban structures. To have a realistic results of the pounding effects in modeling process of retrofitting buildings, the present research provides seismic Probability Factors (PFs), which can be used for estimating collision effects without engaging in intricate and time-intensive analysis. To include the low-, to mid-rise buildings, the 3-Story, 5-Story, and 9-Story adjacent steel and Reinforced Concrete (RC) moment-resisting frames were modeled in OpenSees software capable to take into account the structure in a state of collapse during the analysis, which can provide the real condition of buildings under seismic excitations. Results of analysis confirmed that the impact force can considerably affect the moment–rotation curve of beams and columns, in which, it can affect the structural response of structures during earthquakes. Therefore, seismic PFs proposed to examine the possibility of changes in the performance levels and fragility assessments. Moreover, proposed PFs can be used as coefficient factors to facilitate the retrofitting process of buildings and improve the environmental effects.

  • Seismic response and performance prediction of steel buckling-restrained braced frames using machine-learning methods
    • Neda Asgarkhani
    • Farzin Kazemi
    • Anna Jakubczyk-Gałczyńska
    • Benyamin Mohebi
    • Robert Jankowski
    2024 Full text ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE

    Nowadays, Buckling-Restrained Brace Frames (BRBFs) have been used as lateral force-resisting systems for low-, to mid-rise buildings. Residual Interstory Drift (RID) of BRBFs plays a key role in deciding to retrofit buildings after seismic excitation; however, existing formulas have limitations and cannot effectively help civil engineers, e.g., FEMA P-58, which is a conservative estimation method. Therefore, there is a need to provide a comprehensive tool for estimating seismic responses of Interstory Drift (ID) and RID with novel approaches to fulfill the shortcomings of existing formulas. The Machine Learning (ML) method is an interdisciplinary approach that makes it possible to solve these types of engineering problems. Therefore, the current study proposes ML algorithms to provide a prediction model for determining the seismic response, seismic performance curve, and seismic failure probability curve of BRBFs. To train ML-based prediction models, Nonlinear Time-History Analysis (NTHA) and Incremental Dynamic Analysis (IDA) were performed on the 2-, to 12-Story BRBFs subjected to 78 far-field ground motions, and 606944 data points were prepared for different prediction purposes. The results indicate that the considered approaches are justified. For instance, the proposed ML methods have the ability to predict the maximum ID, maximum RID and maximum roof ID with the accuracy of even 98.7%, 95.2%, and 93.8%, respectively, for the 4-Story BRBF. Moreover, a general preliminary estimation tool is introduced to provide predictions based on the input parameters considered in the study.

  • Selected aspects of performance of organic Rankine cycles incorporated into bioenergy with carbon capture and storage using gasification of sewage sludge
    • Kamil Stasiak
    • Paweł Ziółkowski
    • Dariusz Mikielewicz
    2024 Full text JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME

    The study aims to investigate the application of the Organic Rankine Cycle (ORC) in the bioenergy with carbon capture and storage (BECCS) using gasification of sewage sludge. The tool used in the investigation is the Aspen Plus software with REFPROP property methods for calculating fluid properties. The reason for this study is that a detailed analysis of the proposed BECCS process flow diagram indicates that a certain amount of waste heat is available in the exhaust gas from the high-to-intermediate pressure gas turbine. Some of this energy can be used by applying expansion in a low-pressure turbine, optionally by applying of regenerative water heating, which is then redirected to the combustion chamber, or finally by incorporating the ORC into the main cycle. For the ORC cycle, different configurations are studied, with regeneration and using different working fluids. For the highest efficiency of the cycle, the regenerative heating of high-pressure water is applied and a suitable ORC working fluid with optimal saturation parameters and mass flow is selected. Such modified proposed BECCS power plant hybrid systems with ORC are compared to the reference case with lower pressure expansion. A study of the heat duty and temperature distribution in heat exchangers is carried out. Five ORC fluids were investigated, namely ethanol, refrigerants R236-ea, R245-fa, R1233zd(E) and water, which gave a net efficiency of the whole power plant of 39.71%, 40.02%, 40.26%, 40.34% and 39.35% respectively, while the proposed BECCS reference case gave 38.89%.

  • Selected aspects of the operation of Dual Active Bridge DC/DC converters
    • Serafin Bachman
    • Marek Turzyński
    • Marek Jasinski
    2024 Full text Bulletin of the Polish Academy of Sciences-Technical Sciences

    This review paper discusses the concept of a bidirectional dual active bridge (DAB) DC/DC converter. Practical applications and control methods are explored, and various types of DAB converters are introduced and characterized. Aspects of operation are discussed, and enriched by the results of theoretical analyses, simulations, and experimental measurements of the original authors’ work.

  • Selected symmetrically substituted carbazoles: Investigation of anticancer activity and mechanisms of action at the cellular and molecular levels
    • Mateusz Olszewski
    2024 Full text

    DNA topoisomerases play a critical role as essential enzymes in controlling alterations in the topology of DNA. They achieve this by orchestrating the coordinated process of breaking and rejoining DNA strands, which is crucial for maintaining the proper structure of DNA during regular cellular development. The search for and development of new potential anticancer drugs is a challenging yet immensely important area of research that can contribute significantly to advancements in the treatment and combat of cancer-related diseases. In the scope of my doctoral work, research was conducted on three heterocyclic compounds derived from carbazole, aiming to identify their anticancer mechanism of action. The studies demonstrated that these compounds act as non-intercalating DNA inhibitors of human topoisomerase I and IIα. Among the three investigated compounds, 36a exhibited notably higher inhibitory activity against the IIα isoform compared to IIβ. Additionally, their cytotoxic and antiproliferative properties were determined, along with their ability to inhibit tyrosine protein kinases and induce cell death. The conducted experiments allowed to determine the main mechanisms of action of these anticancer compounds, which could in the future contribute to the design and synthesis of new potential drug candidates.

  • Selecting a transport and forwarding company for meeting a customer’s needs when organizing international road cargo transportation
    • Ievgenii Lebid
    • Nataliia Luzhanska
    • Iryna Lebid
    • Alexander Mazurenko
    • Inesa Halona
    • Kateryna Kovtsur
    • Tetiana Yarmak
    • Tetiana Sotnikova
    • Ievgen Medvediev
    2024 Full text Eastern-European Journal of Enterprise Technologies [ Восточно-Европейский журнал передовых технологий ]

    The object of this study is the process of planning the work of a manufacturing enterprise that needs transport and forwarding services when exporting goods to counterparties in different countries of the world. The problem being solved is predetermined by the need to devise recommendations for choosing a transport and forwarding company when serving an individual customer, based on its individual needs and conditions of cooperation. A simulation model for the selection of a transport and forwarding company was constructed and implemented to meet the customer’s needs when exporting goods, applying the GPSS World simulation automation package. The model provides for the optimization of the choice of a transport and forwarding company for servicing counterparties based on the assessment of their activity indicators over previous periods of cooperation. When building the model, the types of commercial conditions of the exporter’s cooperation with the transport and forwarding company, indicators of the quality assessment of the basic level of service and the duration of service at all stages of the foreign trade operation were taken into account. The application of the constructed model in practice will enable exporters and importers to choose a transport and forwarding company depending on the individual needs of customers in the delivery of goods. The simulation results reflect the performance indicators of the provision of transport and forwarding services by various specialized enterprises. This will make it possible to involve in the transport and forwarding service of a separate counterparty an organization that will meet all the requirements of goods buyer in accordance with the terms of the international economic contract. At the same time, the duration of choosing and agreeing the terms of cooperation could be reduced by 12–15 % while the efficiency of transport and forwarding services would increase by 13–16 %.

  • Selective H2 production from plastic waste through pyrolysis and in-line oxidative steam reforming
    • Mayra Suarez
    • Katarzyna Januszewicz
    • Maria Cortazar
    • Lopez Gartzen
    • Laura Santamaria
    • Martin Olazar
    • Maite Artetxe
    • Maider Amutio
    2024 Full text ENERGY

    This study deals with the proposal of pyrolysis and in-line oxidative steam reforming (P-OSR) for plastic waste valorization and assesses the potential of this strategy for the selective production of H2. Overall, the study aims at progressing towards the fine-tuning of the pyrolysis-reforming technology by co-feeding O2. Thus, a multi-point O2 injection system has been developed to ensure a suitable O2 distribution in the reforming reactor and avoid the formation of hot spots, as they may cause catalyst deactivation by metal sintering. Moreover, as O2 is directly supplied into the catalytic bed, pre-combustion of the volatile stream before contacting the catalyst is avoided and in-situ coke combustion is promoted. The P-OSR of HDPE was carried out in a two-step reaction system, which combines CSBR (conical spouted bed reactor) and FBR (fluidized bed reactor) technologies. The experiments were conducted in continuous mode and the influence of the main process conditions at zero time on stream was analyzed. Thus, the effect of reforming temperature was studied in the 550–750 °C range, that of the space time from 3.12 to 15.62 gcat min gHDPE−1, steam to plastic (S/P) ratio between 2 and 5 and equivalence ratio (ER) from 0 to 0.3. Under the optimum conditions (700 °C, S/P of 3, 12.5 gcat min gHDPE−1 and ER of 0.2), a H2 production of 25.0 wt% was obtained, which is only 28.6 % lower than that obtained in the conventional pyrolysis-steam reforming (P-SR) process. The results obtained confirm the potential of continuous P-OSR process for the selective production of H2.

  • Self-assembled concentric stripes of diamond particles by a pinning-depinning mechanism
    • Paulina Czarnecka-Trela
    • Adam M. Wojciechowski
    • Mariusz Mrózek
    • Maciej Głowacki
    • Robert Bogdanowicz
    • Wojciech Gawlik
    2024 Full text DIAMOND AND RELATED MATERIALS

    We describe the novel mechanism of spontaneous formation of the concentric stripe patterns of microdiamonds via gradual solvent evaporation from a suspension confined in a teardrop well. The self-organized patterns exhibit a series of arcs with regular spacings varying between hundreds of micrometers and millimeters. They result from an interplay between the directional forced circulation of the solvent and a stick-slip movement of its contact line during the gradual drying of the suspension. We reveal the mechanism of the phenomenon and discuss the effects of various parameters on the obtained structures.

  • Self-organising maps in the analysis of strains of human abdominal wall to identify areas of similar mechanical behaviour.
    • Mateusz Troka
    • Katarzyna Szepietowska
    • Izabela Lubowiecka
    2024 Full text Journal of the Mechanical Behavior of Biomedical Materials

    The study refers to the application of a type of artificial neural network called the Self-Organising Map (SOM) for the identification of areas of the human abdominal wall that behave in a similar mechanical way. The research is based on data acquired during in vivo tests using the digital image correlation technique (DIC). The mechanical behaviour of the human abdominal wall is analysed during changing intra-abdominal pressure. SOM allow to study simultaneously three variables in four time/load steps. The variables refer to the principal strains and their directions. SOM classifies all the abdominal surface data points into clusters that behave similarly in accordance with the 12 variables. The analysis of the clusters provides a better insight into abdominal wall deformation and its evolution under pressure than when observing a single mechanical variable. The presented results may provide a better understanding of the mechanics of the living human abdominal wall. It might be particularly useful when selecting proper implants as well as for the design of surgical meshes for the treatment of abdominal hernias, which would be mechanically compatible with identified regions of the human anterior abdominal wall, and possibly open the way for patient-specific solutions.

  • Self-Perceived Personal Brand Equity of Knowledge Workers by Gender in Light of Knowledge-Driven Organizational Culture: Evidence From Poland and the United States
    • Wioleta Kucharska
    2024 Full text SAGE Open

    This study contributes to the limited literature on the personal branding of knowledge workers by revealing that a culture that incorporates knowledge, learning, and collaboration supports (explicit and tacit) knowledge sharing among employees and that sharing matters for knowledge workers’ self-perceived personal brand equity. Analysis of 2,168 cases from the United States and Poland using structural equation modeling (SEM) showed that this knowledge-sharing mechanism differs by country and gender. Findings revealed that in the United States, the knowledge culture and collaboration culture are highly correlated and dominate the learning culture. In both countries, the mistake acceptance component of the learning culture is not supported by knowledge culture as strongly as is the climate component. These findings reveal a bias concerning the acceptance of mistakes as a potential source of learning observed if the culture of knowledge dominates. Moreover, this study uncovers some significant gender differences that might be caused by the gender stereotypes existing in STEM (science, technology, engineering, mathematics). Finally, the study confirms that knowledge workers’ personal branding is a potent motive to smoothen and increase the knowledge-sharing flow in knowledge-driven organizations.

  • Semi-definite programming and quantum information
    • Piotr Mironowicz
    2024 Full text Journal of Physics A-Mathematical and Theoretical

    This paper presents a comprehensive exploration of semi-definite programming (SDP) techniques within the context of quantum information. It examines the mathematical foundations of convex optimization, duality, and SDP formulations, providing a solid theoretical framework for addressing optimization challenges in quantum systems. By leveraging these tools, researchers and practitioners can characterize classical and quantum correlations, optimize quantum states, and design efficient quantum algorithms and protocols. The paper also discusses implementational aspects, such as solvers for SDP and modeling tools, enabling the effective employment of optimization techniques in quantum information processing. The insights and methodologies presented in this paper have proven instrumental in advancing the field of quantum information, facilitating the development of novel communication protocols, self-testing methods, and a deeper understanding of quantum entanglement.

  • Sensitive method for determination of benzoic acid in beverages and food samples using air–assisted hydrophobic deep eutectic solvent-based dispersive liquid-liquid microextraction
    • Hameed Haq
    2024 Sustainable Chemistry and Pharmacy

    A simple, reliable and rapid air–assisted hydrophobic deep eutectic solvent-based dispersive liquid–liquid microextraction (AA-HDES-DLLME) was developed for analysis of benzoic acid in various beverages and food samples. The final determination stage was performed via UV–visible spectrophotometry. The key parameters (extraction time, HDES type and volume, dispersant volume, pH and sample volume) of the AA-HDES-DLLME method were optimized in detailed using Box–Behnken design. Analysis of variance was used for statistical analysis. Under the optimized conditions, limit of detection (12.1 μg L−1), limit of quantification (40 μg L−1), linearity range (40–1000 μg L−1), and preconcentration factor (140) were determined. While the accuracy of the AA-HDES-DLLME method was investigated with the standard addition approach, its precision was investigated with intraday/interday studies. The method proved to be effective for routine analytical practice for a wide variety of samples. The novelty of the AA-HDES-DLLME method is that it enables the extraction of benzoic acid without the need for heating or centrifugation steps. In this way, the AA-HDES-DLLME method enabled selective extraction of benzoic acid in a shorter time and using less energy compared to similar studies.

  • Sensorless Control of Induction Motor Based on Super-Twisting Sliding Mode Observer With Speed Convergence Improvement
    • Lelisa Wogi
    • Marcin Morawiec
    • Tadele Ayana
    2024 Full text IEEE Access

    The super twisting sliding-mode observer (ST-SMO) has been proposed to achieve an effective method for alleviating low-order harmonics of measured quantities, issues related to DC drift, and suppression of chattering due to low-frequency sampling. The conventional ST-SMO, on the other hand, suffers from control delay in the convergence trajectory due to the system disturbance, resulting in decreased anti-disturbance capability and impacting the estimation accuracy and energy consumption. This paper proposed an ST-SMO with convergence improvement to address the issue related to the sliding mode controller along the sliding surface. A nonlinear sliding mode manifold is created to achieve the optimal ST-SMO convergence trajectory along the sliding surface. Then, a disturbance compensation term is added to the control law to eliminate the system control delay. In comparison to the conventional ST-SMO, the investigated method can effectively improve the anti-disturbance capability of the induction motor (IM) Observer, resulting in improved speed estimation (rotor flux control under applied load torque disturbances, speed reversal, and zero speed operation), good performance, and stability. The simulation and experimental studies are carried out for an induction motor with a 5.5kW rating. Both simulation and experimental results prove good robustness against the applied load torque disturbances and convergence of rotor speed to its actual value.

  • Sensorless Predictive Multiscalar-Based Control of the Five-Phase IPMSM
    • Deepak Vyas
    • Marcin Morawiec
    • Grzegorz Kostro
    • Andrzej JąDerko
    • Janusz Baran
    2024 Full text IEEE Access

    This article proposes multi-scalar variables based predictive control of sensorless multiphase interior permanent magnet synchronous machine. Estimated parameters from adaptive observers are used to implement the proposed control scheme. The control approach is divided into two parts: for the fundamental plane, torque and its dual quantity from the multi-scalar model are directly predicted by the controller, and torque density is improved by injecting a third harmonic current in the second plane. The multi-scalar model of the 3rd harmonic plane is controlled by classical linear controllers. The analysis of the five-phase interior permanent magnet synchronous machine is done deeply in the stationary reference frame. Moreover, the proposed control scheme is compared with traditional predictive control-based field-oriented control for the fundamental plane and the field-oriented control (linear controllers-based) for the second plane in the (d-q) reference frame. Compared with the previous control strategy, the proposed control structure provides a fastdynamic response, reduces the computation resources by eliminating the reference frame transformation to obtain control signals, and improves overall control dynamics. The performance of the proposed control scheme is formally validated by simulation and experimental results.

  • Separation of C6 hydrocarbons on sodium dithionite reduced graphene oxide aerogels
    • Maksymilian Plata Gryl
    • Roberto Castro Munoz
    • Emilia Gontarek-Castro
    • Grzegorz Boczkaj
    2024 JOURNAL OF CHROMATOGRAPHY A

    The ability of reduced graphene oxide aerogels (rGOAs) for challenging gas-phase separation was investigated with hexane isomers and benzene (C6 hydrocarbons) using inverse gas chromatography (IGC). For the first, rGOAs were synthesized with sodium dithionite (DTN) as a reductant. Experiments revealed that the most optimal DTN to graphene oxide mass ratio was 2:1, resulting in the highest specific surface area of 432.3 m2 g−1 and the highest degree of graphitization among analyzed samples. C6 hydrocarbon adsorption tests demonstrated the dominant role of the kinetic effect for the adsorption of branched and cyclic hexane isomers -the partition coefficient decreased as the molecule kinetic diameter increased. The contribution of thermodynamic effects was distinguished for molecules with uneven charge distribution. A comparison of the partition coefficient ratios for different pairs of hydrocarbons demonstrated the potential of rGOAs in separating various C6 hydrocarbons. The selectivity, calculated from binary-component adsorption tests of benzene (Bz)/cC6 equimolar mixture, was 13.7, 8.5 and 2.8 for DTN4, DTN2, and DTN1. The research indicates that rGOAs may have potential as adsorbents for the selective separation of hydrocarbons, however, the competitive adsorption and performance at high surface coverages of adsorbates have to be accounted for in further research to assess the applicability of rGOAs reliably.

  • settingsOrder Article Reprints This is an early access version, the complete PDF, HTML, and XML versions will be available soon. Open AccessArticle Investigation of the Frying Fume Composition During Deep Frying of Tempeh Using GC-MS and PTR-MS
    • Rohmah Nur Fathimah
    • Tomasz Majchrzak
    2024 MOLECULES

    This study employed proton transfer reaction mass spectrometry (PTR-MS) and gas chromatography–mass spectrometry (GC-MS) to identify and monitor volatile organic compounds (VOCs) in frying fumes generated during the deep frying of tempeh. The research aimed to assess the impact of frying conditions, including frying temperature, oil type, and repeated use cycles, on the formation of thermal decomposition products. A total of 78 VOCs were identified, with 42 common to both rapeseed and palm oil. An algorithm based on cosine similarity was proposed to group variables, resulting in six distinct emission clusters. The findings highlighted the prominence of saturated and unsaturated aldehydes, underscoring the role of fatty acid oxidation in shaping the frying fume composition. This study not only corroborates previous research but also provides new insights into VOC emissions during deep frying, particularly regarding the specific emission profiles of certain compound groups and the influence of frying conditions on these profiles.

  • Sewage sludge co-pyrolysis with agricultural/forest residues: A comparative life-cycle assessment
    • Mohamed A. Badr
    • Roger Ruan
    • Muhammad Bilal
    • Selvakumar Periyasamy
    • Mukesh Kumar Awasthi
    • Natarajan Rajamohan
    • Lijian Leng
    2024 RENEWABLE & SUSTAINABLE ENERGY REVIEWS

    This study aims to determine the sustainability and energy efficiency of co-pyrolysis scenarios as treatment processes for municipal sewage sludge through a life cycle assessment (LCA). In addition, sensitivity and energy recovery analyses are conducted to determine the possible methods for optimizing the co-pyrolysis process from a circular bioeconomy perspective. Corncob and wood residue have been selected as potential co-feed materials for co-pyrolysis with sewage sludge at three mixing ratios (25, 50, and 75 wt%). The functional unit (FU) for this study is 1000 kg of dried single or mixed feedstock. LCA results indicate that sewage sludge, in a singular pyrolysis scenario, demonstrated the most unfavorable outcome by causing a rise in all negative environmental indicators. In contrast, the overall environmental impacts are reduced by up to 48 %, when the sewage sludge is mixed with co-feed biomass (wood or corncobs), with corncob co-pyrolysis performing better than wood residue in most impact indicators. Energy recovery from a gas turbine provides significant benefits, generating about nine times of the required energy for gas turbine operation and supplying sufficient energy to sustain the whole process. This is notably evident for corncob co-pyrolysis, where the energy produced from gas recovery is equivalent to 59–181 % of energy requirement of the whole process and achieved the highest net positive energy balance (+1368 kWh/FU). Sensitivity analysis indicates that co-pyrolysis is more sensitive to bio-oil yield fluctuations and feedstock transportation. In conclusion, this study establishes that sewage sludge co-pyrolysis is a more environmentally friendly treatment approach when compared to single pyrolysis.

  • Sex contribution to average age at onset of Huntington's disease depends on the number of (CAG)n repeats
    • Anna Stanisławska-Sachadyn
    • Michał Krzemiński
    • Daniel Zielonka
    • Magdalena Krygier
    • Ewa Ziętkiewicz
    • Jarosław Sławek
    • Janusz Limon
    2024 Scientific Reports

    Huntington’s disease (HD) is a hereditary neurodegenerative disorder caused by the extension of the CAG repeats in exon 1 of the HTT gene and is transmitted in a dominant manner. The present study aimed to assess whether patients’ sex, in the context of mutated and normal allele length, contributes to age on onset (AO) of HD. The study population comprised a large cohort of 3723 HD patients from the European Huntington’s Disease Network’s REGISTRY database collected at 160 sites across 17 European countries and in one location outside Europe. The data were analyzed using regression models and factorial analysis of variance (ANOVA) considering both mutated allele length and sex as predictors of patients’ AO. AO, as described by the rater’s estimate, was found to be later in affected women than in men across the whole population. This difference was most pronounced in a subgroup of 1273 patients with relatively short variants of the mutated allele (40–45 CAG repeats) and normal alleles in a higher half of length distribution—namely, more than 17 CAG repeats; however, it was also observed in each group. Our results presented in this observational study point to sex-related differences in AO, most pronounced in the presence of the short mutated and long normal allele, which may add to understanding the dynamics of AO in Huntington’s Disease.

  • Shallow Water Communication with an Object Buried in Bottom Sediments
    • Roman Salamon
    • Jacek Marszal
    • Iwona Kochańska
    2024 International Journal of Electronics and Telecommunications

    Underwater acoustic communications (UAC) in shallow water applications is a very difficult task. This task becomes even more difficult when there is a need to ensure reliable communication with an object buried in bottom sediments. The article presents a simulation of an acoustic transmission channel in conditions of strong multi-path propagation to an object buried in bottom sediments. The impulse response method was used, supported by a technique derived from the ray tracing image source method. Simulation results are presented for both narrowband and broadband signals with LFM frequency modulation. Based on the simulation, the conditions that should be met by the transmission signals to ensure correct communication were determined. Examples of data transmission to an object buried in bottom sediments in a simulated shallow channel with multi-path propagation were also presented.

  • Shallow-Water Acoustic Communications in Strong Multipath Propagation Conditions
    • Iwona Kochańska
    • Aleksander Schmidt
    • Jan Schmidt
    2024

    A phenomenon that has a strong impact on signal transmission conditions in Underwater Acoustic Communication (UAC) systems is multipath propagation. As a result of multipath propagation, the transmitted signal undergoes time dispersion which results in inter-symbol interference observed on the receiving side. Time dispersion is large, especially in horizontal channels in shallow waters which significantly limits the transmission capabilities of UAC systems operating in these channels. In particularly difficult propagation conditions, such as observed in very shallow-water channel, it may be impossible to obtain reliable data transmission without using a matched filtering algorithm in the receiver.The paper presents the results of data transmission tests using three kinds of signals that require the matched filters in the receiver, namely: Direct-Sequence Spread Spectrum (DSSS) waveforms, Linear Frequency Modulated (LFM) waveforms, and Multi-LFM waveforms. The tests were performed with the use of impulse responses of the UAC channel measured during the experiment in a very shallow water in a configuration where the receiving transducer is located at the bottom of the reservoir.

  • Short-Term Observations of Rainfall Chemistry Composition in Bellsund (SW Spitsbergen, Svalbard)
    • Sara Lehmann-konera
    • Marek Ruman
    • Marcin Frankowski
    • Łukasz Małarzewski
    • Krzysztof Raczyński
    • Filip Pawlak
    • Joanna Jóźwik
    • Joanna Potapowicz
    • Żaneta Polkowska
    2024 Full text Water

    Global warming results in increasingly widespread wildfires, mostly in Siberia, but also in North America and Europe, which are responsible for the uncontrollable emission of pollutants, also to the High Arctic region. This study examines 11 samples of rainfall collected in August in a coastal area of southern Bellsund (Svalbard, Norway). It covers detailed analysis of major ions (i.e., Cl−, NO3−, and SO42−) and elements (i.e., Cu, Fe, Mn, Pb, and Zn) to Hybrid Single-Particle Langrarian Integrated Trajectory( HYSPLIT) backward air mass trajectories. The research of wildfires, volcanic activities, and dust storms in the Northern Hemisphere has permitted the assessment of their relations to the fluctuations and origins of elements. We distinguished at least 2 days (27 and 28 August) with evident influence of volcanic activity in the Aleutian and Kuril–Kamchatka trenches. Volcanic activity was also observed in the case of the Siberian wildfires, as confirmed by air mass trajectories. Based on the presence of non-sea K (nsK), non-sea sulphates (nss), and Ca (the soil factor of burned areas), the continuous influence of wildfires on rainfall chemistry was also found. Moreover, dust storms in Eurasia were mainly responsible for the transport of Zn, Pb, and Cd to Svalbard. Global warming may lead to the increased deposition of mixed-origin pollutants in the summer season in the Arctic

  • Siedlce nieoczywiste
    • Marta Koperska-Kośmicka
    • Agnieszka Kurkowska
    2024

    Wycieczka dydaktyczna z elementami urban sketchingu, mająca za zadanie przybliżyć uczestnikom historię architektury gdańskiej dzielnicy Siedlce. Szybkie szkice in situ były rodzajem notatnika terenowego, pozwalającego na graficzny zapis poznawanej przestrzeni.

  • Sign Language Recognition Using Convolution Neural Networks
    • Jarosław Kobiela
    • Dariusz Kobiela
    • Adam Artemiuk
    2024 Full text

    The objective of this work was to provide an app that can automatically recognize hand gestures from the American Sign Language (ASL) on mobile devices. The app employs a model based on Convolutional Neural Network (CNN) for gesture classification. Various CNN architectures and optimization strategies suitable for devices with limited resources were examined. InceptionV3 and VGG-19 models exhibited negligibly higher accuracy than our own model, but they also had more complicated architectures. The best method for network optimization became Layer Decomposition which achieved the lowest inference time in classification effectiveness. Each optimization method reduced the inference time of our model at the small expense of classification accuracy. The accelerators with the shortest inference time were GPU and CPU in a configuration of 5 threads. For the purpose of loading the trained models, running and testing their effectiveness under different hardware configurations a prototype of the mobile application was developed: https://github.com/DariuszKobiela/sign-language-recognition-using-CNN

  • Silver nanoparticles incorporated with superior silica nanoparticles-based rice straw to maximize biogas production from anaerobic digestion of landfill leachate
    • Mona T. Al-shemy
    • Filip Gamoń
    • Aly Al-sayed
    • Mohamed S. Hellal
    • Aleksandra Ziembińska-Buczyńska
    • Gamal K. Hassan
    2024 JOURNAL OF ENVIRONMENTAL MANAGEMENT

    Treating hazardous landfill leachate poses significant environmental challenges due to its complex nature. In this study, we propose a novel approach for enhancing the anaerobic digestion of landfill leachate using silver nanoparticles (Ag NPs) conjugated with eco-friendly green silica nanoparticles (Si NPs). The synthesized Si NPs and Ag@Si NPs were characterized using various analytical techniques, including transmission electron micro- scopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The anaerobic digestion performance of Si NPs and Ag@Si NPs was tested by treating landfill leachate samples with 50 mg/L of each NP. The results demonstrated an enhancement in the biogas production rate compared to the control phase without the nano- composite, as the biogas production increased by 14% and 37% using Si NPs and Ag@Si NPs. Ag@Si NPs effectively promoted the degradation of organic pollutants in the leachate, regarding chemical oxygen demand (COD) and volatile solids (VS) by 58% and 65%. Furthermore, microbial analysis revealed that Ag@Si NPs enhanced the activity of microbial species responsible for the methanogenic process. Overall, incorporating AgNPs conjugated with eco-friendly green Si NPs represents a sustainable and efficient approach for enhancing the anaerobic digestion of landfill leachate.

  • Simple Measurement Method for Resistive Sensors Based on ADCs of Microcontrollers
    • Zbigniew Czaja
    2024 IEEE SENSORS JOURNAL

    A new, complete measurement method for resistance measurement of resistive sensors for systems based on microcontrollers equipped with analog-to-digital converters (ADCs) is proposed. The interface circuit consists of only four resistors, including a resistive sensor and a reference resistor, connected directly to the microcontroller pins. It is activated only during measurements, which significantly reduces power consumption. The measurement procedure consists of measuring three voltages via the ADC. Thanks to this, the measurement results of the resistance are independent of the supply and reference voltages, the ON-resistance of the microcontroller pin, and also the offset and gain errors of the ADC. The method is illustrated in the example of a system consisting of an Arduino Micro and a Pt1000. Experimental studies have shown that the relative systematic measurement error of the sensor resistance is less than 0.29%, and the relative random error is less than 0.56%. They result solely from the quantization error of the 10-bit ADC. An oversampling method has also been proposed. With 64 times oversampling, the above errors were reduced to 0.27% and 0.11%, respectively.