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  • Relationship between GIX, SIDX, and ROTI ionospheric indices and GNSS precise positioning results under geomagnetic storms
    • Grzegorz Nykiel
    • Juan Andrés Cahuasquí
    • Mohammed Mainul Hoque
    • Norbert Jakowski
    2024 Pełny tekst GPS SOLUTIONS

    Ionospheric indices give information about ionospheric perturbations, which may cause absorption, diffraction, refraction, and scattering of radio signals, including those from global navigation satellite systems (GNSS). Therefore, there may be a relationship between index values and GNSS positioning results. A thorough understanding of ionospheric indices and their relationship to positioning results can help monitor and forecast the reliability and accuracy of GNSS positioning and support the precision and safety of life applications. In this study, we present the relationship between three indices: Gradient Ionosphere indeX (GIX), Sudden Ionospheric Disturbance indeX (SIDX), and Rate of Total electron content Index (ROTI) in relation to precise positioning results. We used two approaches: precise point positioning (PPP) and relative positioning for long baselines. We focus on GNSS stations located in Europe for two selected geomagnetic storms: March 17, 2015, and May 22, 2015. Our results show that in the case of PPP, positioning degradation occurred mainly at high latitudes and was mostly caused by rapid small-scale changes in ionospheric electron content represented by SIDX and ROTI. We also showed a significant correlation between cycle slips of GNSS signals and ROTI (0.88). The most significant degradations for relative positioning for low and medium latitudes were associated with large spatial gradients reflected by the GIX.

  • Removal of phenolic inhibitor compounds from hydrolysates and post-fermentation broths by using a Hydrophobic Magnetic Deep Eutectic Solvent
    • Zhila Honarmandrad
    • Karolina Kucharska
    • Massoud Kaykhaii
    • Jacek Gębicki
    2024 Journal of Environmental Chemical Engineering

    Hydroxymethylfurfural (HMF), furfural (FF), hydroquinone (HQ), and vanillin (VAN) are among the main inhibitors generated during most of biomass pre-treatments prior to fermentation processes. They are recognized as toxic to several fermentative microorganisms and therefore cause a decrease in biohydrogen or biofuel production (after hydrolysis). Moreover, if they are released into aqueous solutions (after fermentation), they can be detrimental to the ecosystem. In this research, a new method for removing these inhibitor compounds from the broth after hydrolysis and fermentation is proposed. A hydrophobic magnetic deep eutectic solvent (HMDES), based on menthol: nonanoic acid in a mole ratio of 2:1 was prepared and magnetized with Fe3O4 nanoparticles and applied for effective sorption and removal of these inhibitors from the broth after fermentation and for biomass hydrolysates. Parameters affecting sorption, such as pH, volume of the inhibitors, initial concentration of inhibitors, volume of HMDES, temperature, stirring speed, and contact time, were studied and optimized. Under optimum conditions, the removal efficiency for HQ, HMF, FF, and VAN was obtained as 92.97, 86.72, 82.86 and 95.12% for the model samples. In addition, the removal efficiency of real samples after hydrolysis and fermentation for HQ, HMF, FF and VAN were higher than 83.3, 71.42, 69.99 and 76.80%, respectively. The studies on HMDES regeneration revealed that the removal efficiency remained constant even after undergoing 13 cycles of regeneration. The mechanism of inhibitor removal suggests that hydrogen bonding or van der Waals interactions may serve as the predominant factor influencing the extraction process.

  • Removal of selected sulfonamides and sulfonamide resistance genes from wastewater in full-scale constructed wetlands
    • Ewa Felis
    • Adam Sochacki
    • Sylwia Bajkacz
    • Aneta Łuczkiewicz
    • Krzysztof Józwiakowski
    • Joan García
    • Jan Vymazal
    2024 SCIENCE OF THE TOTAL ENVIRONMENT

    Sulfonamides are high-consumption antibiotics that reach the aquatic environment. The threat related to their presence in wastewater and the environment is not only associated with their antibacterial properties, but also with risk of the spread of drug resistance in bacteria. Therefore, the aim of this work was to evaluate the occurrence of eight commonly used sulfonamides, sulfonamide resistance genes (sul1–3) and integrase genes intI1–3 in five full-scale constructed wetlands (CWs) differing in design (including hybrid systems) and in the source of wastewater (agricultural drainage, domestic sewage/surface runoff, and animal runs runoff in a zoo). The CWs were located in low-urbanized areas in Poland and in Czechia. No sulfonamides were detected in the CW treating agricultural tile drainage water. In the other four systems, four sulfonamide compounds were detected. Sulfamethoxazole exhibited the highest concentration in those four CWs and its highest was 12,603.23 ± 1000.66 ng/L in a CW treating a mixture of domestic sewage and surface runoff. Despite the high removal efficiencies of sulfamethoxazole in the tested CWs (86 %–99 %), it was still detected in the treated wastewater. The sul1 genes occurred in all samples of raw and treated wastewater and their abundance did not change significantly after the treatment process and it was, predominantly, at the level 105 gene copies numbers/mL. Noteworthy, sul2 genes were only found in the influents, and sul3 were not detected. The sulfonamides can be removed in CWs, but their elimination is not complete. However, hybrid CWs treating sewage were superior in decreasing the relative abundance of genes and the concentration of SMX. CWs may play a role in the dissemination of sulfonamide resistance genes of the sul1 type and other determinants of drug resistance, such as the intI1 gene, in the environment, however, the magnitude of this phenomenon is a matter of further research.

  • Reply to Comment on ‘Nanodiamond incorporated human liver mimicking phantoms: prospective calibration medium of magnetic resonance imaging’
    • Paweł Wierzba
    • Anna Sękowska-Namiotko
    • Agnieszka Sabisz
    • Monika Kosowska
    • Lina Jing
    • Robert Bogdanowicz
    • Małgorzata Szczerska
    2024 MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE

    Dependence of the spin–lattice (T1) relaxation times on the nanodiamond concentration in human liver phantoms is discussed. Factors affecting stability and and reproducibility of these phantoms are presented. The need for comparative measurements on multiple MRI scanners for better understanding of potential variations in the obtained imaging data is emphasised.

  • Research of chitosan coatings deposited by electrophoretic deposition method at various voltage and time parameters
    • Klaudia Malisz
    • Beata Świeczko-Żurek
    • Olive Jean-marc
    • Gilles Pecastaings
    • Alina Sionkowska
    • Aleksandra Laska
    • Grzegorz Gajowiec
    2024 MATERIALS CHEMISTRY AND PHYSICS

    The aim of this research is to estimate the electrophoretic deposition main parameters, such as voltage and time duration, that will provide optimal characteristics of the surface layer. Chitosan coatings were synthesized on biomedical Ti13Zr13Nb alloys at 20 V and 30 V and with deposit times of 2min, 5 min, 10 min, and 15 min. Evaluation of the coating was performed by using Scanning Electron Microscope (SEM), Energy-Dispersive Spectroscopy (EDS), Laser-Induced Breakdown Spectroscopy (LIBS), Atomic Force Microscopy (AFM), drop shape analyzer and nanoscratch tester. Homogeneous and continuous coatings are obtained for 2 min and 5 min, regardless of the voltage. Defects in form of bubbles are observed only for 20 V during 10 min, 20 V during 15 min, and 30 V during 10 min. All of the coatings show hydrophilic behavior. The critical loads for delamination range are between 100 mN and 300 mN. It is concluded, that the optimal coating for orthopedic implants is obtained at 20 V, 5 min, because of homogeneity, a contact angle supporting osseointegration and the best adhesion. The optimal one for implant in contact with blood is obtained at 20 V, 2 min, because it is homogenous and shows the lowest hydrophilicity, which should limit the thrombogenicity of the coating.

  • Residual current devices in electric vehicles charging installations
    • Stanisław Czapp
    2024 Pełny tekst Przegląd Elektrotechniczny

    The main requirements of national regulations and international standards regarding protection against electric shock in electric vehicle charging installations are presented. The principles of using residual current devices (RCDs) in such installations are discussed. It is pointed out that RCDs are mandatory equipment for safe charging of electric vehicles. It is noted that the standards require the use of RCDs having an appropriate type of tripping, due to the fact that in the event of an earth fault in the charging circuit, a DC component of significant value may appear in the earth fault current. A new type of residual current devices for DC installations (DC-RCD) has been indicated.

  • Resonant and nonresonant excitation of waves in a planar magnetosonic flow
    • Anna Perelomova
    2024 CONTRIBUTIONS TO PLASMA PHYSICS

    Forced propagation of perturbations in a magnetosonic wave are considered. The driving force may be caused by stimulated Mandelstam–Brillouin scattering of optic waves or by intense magnetosonic exciter. Some heating-cooling function which takes into account radiative cooling and unspecified heating is taken into consideration, as well as nonlinearity of a medium. Both these factors make the excitation particular. The analytical and numerical evaluations reveal that forced oscillations differ essentially from the free propagation and depend on a number of dimensionless parameters such as the ratio of speed of exciter to the eigen speed of excited wave, the ratio of speed of an excited wave to its eigen speed, and the dimensionless magnitude of an exciter. Forced excitation is resonant if speed of an exciter coincides with the eigen speed of excited wave but may give rise to the excited perturbations with the speed different from the eigen one. The preliminary evaluations may be helpful for the controlled excitation of perturbations in natural and laboratory plasma systems and indication of the parameters of an exciter.

  • Resource constrained neural network training
    • Mariusz Pietrołaj
    • Marek Blok
    2024 Pełny tekst Scientific Reports

    Modern applications of neural-network-based AI solutions tend to move from datacenter backends to low-power edge devices. Environmental, computational, and power constraints are inevitable consequences of such a shift. Limiting the bit count of neural network parameters proved to be a valid technique for speeding up and increasing efficiency of the inference process. Hence, it is understandable that a similar approach is gaining momentum in the field of neural network training. In the face of growing complexity of neural network architectures, reducing resources required for preparation of new models would not only improve cost efficiency but also enable a variety of new AI applications on modern personal devices. In this work, we present a deep refinement of neural network parameters limitation with the use of the asymmetric exponent method. In addition to the previous research, we study new techniques of floating-point variables limitation, representation, and rounding. Moreover, by leveraging exponent offset, we present floating-point precision adjustments without an increase in variables’ bit count. The proposed method allowed us to train LeNet, AlexNet and ResNet-18 convolutional neural networks with a custom 8-bit floating-point representation achieving minimal or no results degradation in comparison to baseline 32-bit floating-point variables.

  • Response Feature Technology for High-Frequency Electronics. Optimization, Modeling, and Design Automation
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2024

    This book discusses response feature technology and its applications to modeling, optimization, and computer-aided design of high-frequency structures including antenna and microwave components. By exploring the specific structure of the system outputs, feature-based approaches facilitate simulation-driven design procedures, both in terms of improving their computational efficiency and reliability. These benefits are associated with the weakly nonlinear relationship between feature point coordinates and design variables, which—in the context of optimization—leads to inherent regularization of the objective functions. The book provides an overview of the subject, a definition and extraction of characteristic points, and feature-based design problem reformulation. It also outlines a number of numerical algorithms developed to handle local, global, and multi-criterial design, surrogate modeling, as well as uncertainty quantification. The discussed frameworks are extensively illustrated using examples of real microwave and antenna structures, along with numerous design cases. Introductory material on simulation-driven design, numerical optimization, as well as behavioral and physics-based surrogate modeling is also included. The book will be useful for readers working in the area of high-frequency electronics, including microwave engineering, antenna design, microwave photonics, magnetism and especially those who utilize electromagnetic (EM) simulation models in their daily routines.

  • Response to David Steigmann’s discussion of our paper
    • Thang X. Duong
    • Mikhail Itskov
    • Roger Sauer
    2024 Pełny tekst MATHEMATICS AND MECHANICS OF SOLIDS

    We respond to David Steigmann's discussion of our paper "A general theory for anisotropic Kirchhoff-Love shells with in-plane bending of embedded fibers, Math. Mech. Solids, 28(5):1274-1317" (arXiv:2101.03122). His discussion allows us to clarify two misleading statements in our original paper, and confirm that its formulation is fully consistent with the formulation of Steigmann. We also demonstrate that some of our original statements criticized by Steigmann are not wrong.

  • Reverberation divergence in VR applications
    • Patryk Rolkowski
    • Piotr Odya
    • Bartłomiej Mróz
    2024 International Journal of Electronics and Telecommunications

    This project aimed to investigate the correlation between virtual reality (VR) imagery and ambisonic sound. With the increasing popularity of VR applications, understanding how sound is perceived in virtual environments is crucial for enhancing the immersiveness of the experience. In the experiment, participants were immersed in a virtual environment that replicated a concert hall. Their task was to assess the correspondence between sound scenes (which differed in reverberation times and their characteristics) and the observed invariant visual scene. The research was conducted using paired tests. Participants were asked to identify the sound scene they considered more closely matched the concert hall seen in the VR goggles for each pair. Each sound scene differed in the employed impulse response. All the impulse responses were recorded in real venues such as concert halls, auditoriums, churches, etc. To provide a realistic auditory experience, the sound scenes were processed using third-order ambisonics and decoded using binaural techniques with HRTFs. The virtual concert hall was generated using the Unreal Engine and was the same for all the tests. One of the major conclusions drawn from the conducted research was confirming the role of spatial sound in creating immersive VR experiences. The study demonstrated that appropriately matching spatial sound to the VR visual scene is essential for achieving complete immersion. Additionally, expectations and preferences regarding reverberation characteristics in different types of spaces were discovered. These findings have significant implications for the design of virtual environments, and understanding these aspects can contribute to improving VR technology and creating more immersive and realistic virtual experiences for users.

  • Review of Recent Advancement on Nature/Bio-inspired Antenna Designs
    • Farooq Azam
    • Syed Shah
    • Shahid Bashir
    • Sławomir Kozieł
    2024 Pełny tekst IEEE Access

    This article presents an extensive examination of antennas rooted in nature and biology, showcasing their remarkable performance across a wide spectrum of frequencies—from microwave to terahertz. The limitations of traditional antenna design have become increasingly evident in the face of burgeoning demands for novel communication technologies. Conventional analytical-equation-based approaches struggle to deliver the combined performance characteristics – encompassing bandwidth, gain, radiation pattern, and miniaturization – that emerging technologies necessitate. This has fueled an explosive interest in bio-inspired antenna designs, a paradigm shift drawing inspiration from the ingenious structural solutions found in the living and non-living world, from plant leaves to bird feathers. These bio-inspired designs offer distinct advantages such as broader bandwidth and reduced sizes, making them highly appealing alternatives to the limitations of conventional antenna designs. This review explores a diverse range of bio-inspired designs. Among them are fractal geometries, inspired by self-repeating patterns in nature, which achieve optimal performance. Numerous designs in this category draw inspiration from nature, incorporating patterns observed in snowflakes, tree branches, clouds, and butterflies. Furthermore, nano-antennas have attracted significant attention for their vast potential applications in microwave and optical frequencies, playing a pivotal role in high-resolution spectroscopy, biomedical diagnosis and sensing, quantum photonics, and solar cell applications. By examining design methodologies and potential benefits, this article highlights the transformative potential of nature-inspired antennas. The compelling advantages of bio-inspired approaches necessitate a thorough exploration of their potential, paving the way for the development of next-generation communication systems with unprecedented capabilities.

  • Review of Segmentation Methods for Coastline Detection in SAR Images
    • Marcin Ciecholewski
    2024 Pełny tekst ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING

    Synthetic aperture radar (SAR) images acquired by airborne sensors or remote sensing satellites contain the necessary information that can be used to investigate various objects of interest on the surface of the Earth, including coastlines. The coastal zone is of great economic importance and is also very densely populated. The intensive and increasing use of coasts and changes of coastlines motivate researchers to try to assess the pace of these changes. As remote sensing develops, coastlines are detected using various image processing and analysis methods, including segmentation methods. Segmentation is to allow separating water and land areas in order to obtain contours representing the shorelines of coasts. Its result has direct impact on the accuracy of the obtained contours and is one of the most important steps in image processing. This article presents an overview of state-of-the-art segmentation methods used for detecting and extracting coastlines from SAR images, taking into account the evaluation metrics used in them. Segmentation methods can be divided into three main groups: thresholding methods, active contours, and machine learning approaches. This article presents the theoretical and practical properties of individual groups of segmentation methods, their advantages and disadvantages, and also promising research directions. This article is intended to give researchers insight into existing approaches and to help them propose new, better solutions

  • 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.

  • 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 Pełny tekst 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.

  • 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 Pełny tekst 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.

  • Schemat powstawania rys na przykładzie osiowo rozciąganego pręta żelbetowego
    • Marek Wesołowski
    • Maciej Solarczyk
    2024 Pełny tekst 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.

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

    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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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.

  • 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.

  • 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 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 Pełny tekst 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.

  • 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.

  • Simple smartphone-based methods for the determination of bioactive compounds in wine
    • Kaja Kalinowska
    • Muhammad Saad Hussain
    • Gerjen Herman Tinnevelt
    • Marek Tobiszewski
    2024 FOOD CHEMISTRY

    A set of simple smartphone-based methods of bioactive compounds determination were developed for wine analysis. Procedures for smartphone-based determination of the total content of phenolic compounds, flavonoids, anthocyanins and biogenic amines, as well as measurement of antioxidant activity were developed and fully validated. The experimental setup is based on smartphone and 3D-printed device, though it is very simple and can be conveniently applied in lab and in field. The proposed solutions have satisfactory figures of merit with R2 in the range of 0.9860–0.9981 for linear range. The recoveries were in range 98.6–102%, RSDs up to 4.2% and LODs below 2.3 mg/L. In order to demonstrate the applicability of the proposed procedures, wine samples were analysed using spectrophotometry and newly developed methods. The results of application of smartphone and spectrophotometer are comparable, in terms of validation parameters and measured concentrations in real samples.

  • Simulation Model for Application of the SDN Concept in IMS/NGN Network Transport Stratum
    • Sylwester Kaczmarek
    • Maciej Sac
    • Jakub Adrych
    2024

    The paper presents a simulation model allowing examination of cooperation between two currently used telecommunication networks concepts: IP Multimedia Subsystem/Next Generation Network (IMS/NGN) and Software-Defined Networking (SDN). Application of the SDN architecture elements in IMS/NGN networks will enable unified control and management of transport resources for various transport technologies and equipment manufacturers. However, such a cooperation is a new concept requiring verification, which is the aim of this paper. The structure of the modeled multidomain network and details about the simulator operation are described. Tests proving correctness of its operation are carried out. Selected research results regarding mean Call Set-up Delay and mean Call Disengagement Delay in the considered network are presented demonstrating that the cooperation between IMS/NGN and SDN is possible.