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  • A note on simple bifurcation of equilibrium forms of an elastic rod on a deformable foundation
    • Marek Izydorek
    • Joanna Janczewska
    2023 TOPOLOGY AND ITS APPLICATIONS

    We study bifurcation of equilibrium states of an elastic rod on a two-parameter Winkler foundation. In the article "Bifurcation of equilibrium forms of an elastic rod on a two-parameter Winkler foundation" [Nonlinear Anal., Real World Appl. 39 (2018) 451-463] the existence of simple bifurcation points was proved by the use of the Crandall-Rabinowitz theorem. In this paper we want to present an alternative proof of this fact based on the Krasnosielski theorem.

  • A Novel [4+2] Cycloaddition Reaction Involving Lawesson’s Reagent. Structure and Specific Fragmentations of a New Cyclic 1,2-Thiaphosphinane-4-one
    • Witold Przychodzeń
    • Barbara Kusznierewicz
    2023 PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS

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

  • A novel approach in wood waste utilization for manufacturing of catalyst-free polyurethane-wood composites (PU-WC)
    • Adam Olszewski
    • Paulina Kosmela
    • Łukasz Piszczyk
    2023 Pełny tekst Sustainable Materials and Technologies

    In recent decades, due to the increase in environmental awareness and noticeable environmental degradation, the area of wood waste management has attracted increasing attention. The purpose of this study is to develop a new type of highly filled polyurethane wood-composite (PU-WC) by the utilization of large amount of wood wastes without addition of a catalyst. Although wood-plastic composites (WPCs) are widely known, there is still a lack of knowledge about WPCs with a polyurethane matrix. Obtained results showed that composites with a wood content of up to 80% show mechanical properties to commonly used MDF boards. This may be caused proper adhesion between polyurethane matrix and the wooden filler which was confirmed by scanning electron microscopy. The flexural strength of the manufactured composites varied between 19.25 and 25.11 MPa, while the flexural modulus varied between 966 and 1255 MPa. Dynamic mechanical analysis (DMA) of the composites showed a shift of Tgβ (from −70.3 to −52.3 °C) and Tgα (from 94.9 to 117.8 °C) to higher temperatures with increasing filler amount. The observed shift could be interpreted as a reduction of polymer chain mobility and an increase in cross-linking density of composites with a higher amount of wood. This is caused by chemical reactions between isocyanates and reactive hydroxyl groups on the wood surface. Thermogravimetric analysis has shown that PU-WC degrades in one step with Tmax at around 360 °C and T2% significantly reduce with greater addition of wood. Water absorption tests that water absorption strongly depends on wood content and varies between 13 and 80%. Moreover, cyclic water absorption tests showed no considerable difference between the water adsorption of samples after each cycle. Our work suggests that PU-WC can be used successfully as a potential substitute for wood or different types of wood-plastic composites (WPC).

  • A Novel Approach to Fully Nonlinear Mathematical Modeling of ‎Tectonic Plates
    • Shahriar Dastjerdi
    • Mohammad Malikan
    • Bekir Akgöz
    • Ömer Civalek
    • Victor Eremeev
    2023 Pełny tekst Journal of Applied and Computational Mechanics

    The motion of the Earth's layers due to internal pressures is simulated in this research with an efficient mathematical model. The Earth, which revolves around its axis of rotation and is under internal pressure, will change the shape and displacement of the internal layers and tectonic plates. Applied mathematical models are based on a new approach to shell theory involving both two and three-dimensional approaches. It is the first time studying all necessary measures that increase the accuracy of the obtained results. These parameters are essential to perform a completely nonlinear analysis and consider the effects of the Earth’s rotation around its axis. Unlike most modeling of nonlinear partial differential equations in applied mechanics that only considers nonlinear effects in a particular direction, the general nonlinear terms are considered in the present study, which increases the accuracy of the amount of displacement of the Earth's inner layers. Also, the fully nonlinear and dynamic differential equations are solved by a semi-analytical polynomial method which is an innovative and efficient method. Determining the amount of critical pressure at the fault location that will cause phenomena such as earthquakes is one of the useful results that can be obtained from the mathematical modeling in this research.

  • A novel concept of enhanced direct-contact condensation of vapour- inert gas mixture in a spray ejector condenser
    • Dariusz Mikielewicz
    • Milad Amiri
    • Michał Klugmann
    • Jaroslaw Mikielewicz
    2023 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

    An analytical model of direct steam condensation (DCC) in the novel idea of spray ejector condenser (SEC) in the presence of inert gas has been developed. It is based on continuity, momentum and energy equations for the steam-carbon dioxide mixture and direct contact condensation mechanisms due to heat transfer and concentration. Crucial in the process of DCC is atomisation of the motive fluid in the ejector. The effect of atomised droplet size is exhibiting a significant amplification influence with increasing size of the droplet. Motive fluid is driving the secondary fluid-mixture of steam and inert gas in the Venturi nozzle and is cold enough to cause direct condensation. The intensity of heat transfer process from steam to water when the phases are in direct contact is much higher than the heat transfer intensity in surface heat exchangers. The analytical model pertains to a subcritical flow of a mixture of steam and gas in SEC. The model exhibits satisfactory agreement with experimental data. The model of DCC predicts higher values of temperature drop between inlet and outlet from the mixing section for the case of smaller steam-CO2 flow rates. Increasing the flow rate of steam mixture from 1.2 g/s to 3.6 g/s results in a reduction of steam mixture temperature from 25 ◦C to 14 ◦C respectively, at CO2 flow rate of 6.8 m3 /h. Condensation without presence of CO2 in the same range of steam flow rate, i.e. from 1.2 g/s to 3.6 g/s results in reduction of steam mixture temperature from 56 ◦C to 25 ◦C respectively, confirming in such way the effect of CO2 presence on the efficiency of DCC. Such model allow for discussion of parameters affecting process of condensation in SEC and ability of application such condenser in power plants.

  • A novel DEM-based pore-scale thermal-hydro-mechanical model for fractured non-saturated porous materials
    • Marek Krzaczek
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    2023 Pełny tekst Acta Geotechnica

    Do propagacji pęknięć wykorzystano nowy oparty na DEM, termiczno-hydromechaniczny model dwufazowego przepływu płynu w skali porów rozszerzony o wymianę ciepła w nienasyconych materiałach porowatych o małej porowatości. Wykonano obliczenia numeryczne dla kohezyjnych próbek ziarnistych przy użyciu DEM w pełni sprzężonego z CFD (opartego na sieci przepływu płynu) i wymianą ciepła, który zintegrował mechanikę dyskretną z mechaniką płynów i wymianą ciepła w mezoskali. Zarówno płyn (dyfuzja i adwekcja) i kohezyjne cząstki (przewodnictwo) brały udział w przenoszeniu ciepła. Wyniki stosując sprzężony model termo-hydro-mechaniczny (THM) zostały najpierw porównane z rozwiązaniem analitycznym klasycznego jednowymiarowego transportu ciepła. Wyniki liczbowe i analityczne były w pełni zgodne. Wpływ adwekcji na ochłodzenie na zespół kohezyjnych cząstek został następnie zademonstrowany numerycznie dla niskich i wysokich liczb Pecleta. Wreszcie użyteczność modelu THM została udowodniona w teście skurczu termicznego, w którym zastosowano próbkę złożoną z kohezyjnych cząstek był poddany chłodzeniu, w wyniku czego powstało makropęknięcie. Zbadano wpływ makropęknięcia na rozkład ciśnienia płynu, gęstości, prędkości i temperatury.

  • A novel hybrid adaptive framework for support vector machine-based reliability analysis: A comparative study
    • Shiyuan Yang
    • Zhenyu He
    • Jiangbo Chai
    • Debiao Meng
    • Wojciech Macek
    • Ricardo Branco
    • Shun-Peng Zhu
    2023 Structures

    This study presents an innovative hybrid Adaptive Support Vector Machine - Monte Carlo Simulation (ASVM-MCS) framework for reliability analysis in complex engineering structures. These structures often involve highly nonlinear implicit functions, making traditional gradient-based first or second order reliability algorithms and Monte Carlo Simulation (MCS) time-consuming. The application of surrogate models has proven effective in addressing computational challenges associated with a large number of simulations. Support Vector Machine (SVM), as an emerging machine learning method suitable for small-sample scenarios, offers a well-established theoretical foundation and presents an effective model substitution approach for reliability analysis in engineering structures. However, the existing literature lacks a comprehensive and thorough comparative analysis of SVM's hybrid adaptive modeling approach, encompassing initial sampling methods and learning functions, with regards to both computational efficiency and accuracy. Additionally, there is a gap in adaptive modeling methods capable of accommodating diverse types of input uncertainty, the nonlinearity of limit state functions, and various application scenarios. In response to these gaps, this article introduces the ASVM-MCS framework, which addresses these challenges by considering different types of input variables and various failure modes. Moreover, this study provides a comprehensive evaluation of the ASVM-MCS framework's performance, including its initial sampling methods and learning functions, across a range of application scenarios, such as scenarios involving only random variables, mixed variables, and the reliability of series-parallel systems.

  • A Novel Spatio–Temporal Deep Learning Vehicle Turns Detection Scheme Using GPS-Only Data
    • Mussadiq Abdul Rahim
    • Sultan Daud Khan
    • Salabat Khan
    • Muhammad Rashid
    • Rafi Ullah
    • Hanan Tariq
    • Stanisław Czapp
    2023 Pełny tekst IEEE Access

    Whether the computer is driving your car or you are, advanced driver assistance systems (ADAS) come into play on all levels, from weather monitoring to safety. These modern-day ADASs use various assisting tools for drivers to keep the journey safe; these sophisticated tools provide early signals of numerous events, such as road conditions, emerging traffic scenarios, and weather warnings. Many urban applications, such as car-sharing and logistics, rely on accurate and up-to-date road map data. Map generation methods use a variety of data sources, including but not limited to global positioning systems (GPS). In this research we propose a GPS-only data trajectory analysis and a novel scheme to convert GPS trajectory data to image-based data to train a custom Convolutional Neural Network (CNN) model. The empirical results with an extensive 5-fold cross-validation show that the proposed scheme identifies turn and not turn with more than 94% recall. It outperforms the existing turn detection schemes on two major frontiers, the required data and the accuracy achieved in detecting different driving behaviors.

  • A Numerical Study on Baseline-Free Damage Detection Using Frequency Steerable Acoustic Transducers
    • Octavio Reyes Márquez
    • Beata Zima
    • Jochen Moll
    • Masoud Mohammadgholiha
    • Luca Marchi De
    2023 Pełny tekst

    In structural health monitoring (SHM) a considerable amount of damage detection algorithms based on guided waves (GW) have been developed. Most of them rely on extensive transducer networks, besides preliminary reference measurements of the structures. This originated a growing demand for hardware simplification and cost reduction of the wave-based SHM methods, driving the conception of new solutions enabling both: the reduction in the amount of sensors required for doing measurements, as well as a diminution of quantity of signals needed for the algorithms to work. The simplification in damage detection procedures can be achieved by using a novel type of special shaped frequency steerable acoustic transducers (FSATs). The spiral shape of these FSATs allows focusing wave energy in a certain direction, which is associated with their excitation frequency. Thanks to this property, presence of damage can be established by identifying signal reflections, while its localization can be determined based on time of flight and the relationship between direction of propagation and its spectral content. This article presents the concept of baseline-free damage detection using FSATs over an aluminium plate with point damage through Finite Element (FE) analysis. Numerical simulations were performed for several cases, varying excitation frequency and damage position.

  • A Parallel Corpus-Based Approach to the Crime Event Extraction for Low-Resource Languages
    • Nina Khairova
    • Orken Mamyrbayev
    • Nina Rizun
    • Mariia Razno
    • Galiya Ybytayeva
    2023 Pełny tekst IEEE Access

    These days, a lot of crime-related events take place all over the world. Most of them are reported in news portals and social media. Crime-related event extraction from the published texts can allow monitoring, analysis, and comparison of police or criminal activities in different countries or regions. Existing approaches to event extraction mainly suggest processing texts in English, French, Chinese, and some other resource-rich and well-annotated languages. This paper presents a parallel corpus-based approach that follows a closed-domain event extraction methodology to event extraction from web news articles in low-resource languages. To identify the event, its arguments, and the arguments’ roles in the sourcelanguage part of the corpus we utilize an enhanced pattern-based method that involves the multilingual synonyms dictionary with knowledge about crime-related concepts and logic-linguistic equations. The event extraction from the target-language part of the corpus uses a cross-lingual crime-related event extraction transfer technique that is based on supplementary knowledge about the semantic similarity patterns of the considered pair of languages. The presented approach does not require a preliminarily annotated corpus for training making it more attractive to low-resource languages and allows extracting TRANSFER, CRIME, and POLICE types of events and their seven subtypes from various topics of news articles simultaneously. Implementation of our approach for the Russian-Kazakh parallel corpus of news portals articles allowed obtaining the F1-measure of crime-related event extraction of over 82% for the source language and 63% for the target language.

  • A Perspective on Missing Aspects in Ongoing Purification Research towards Melissa officinalis
    • Roberto Castro Munoz
    • Grzegorz Boczkaj
    • Rene Cabezas
    2023 Pełny tekst Foods

    Melissa officinalis L. is a medicinal plant used worldwide for ethno-medical purposes. Today, it is grown everywhere; while it is known to originate from Southern Europe, it is now found around the world, from North America to New Zealand. The biological properties of this medicinal plant are mainly related to its high content of phytochemical (bioactive) compounds, such as flavonoids, polyphenolic compounds, aldehydes, glycosides and terpenes, among many other groups of substances. Among the main biological activities associated with this plant are antimicrobial activity (against fungi and bacteria), and antispasmodic, antioxidant and insomnia properties. Today, this plant is still used by society (as a natural medicine) to alleviate many other illnesses and symptoms. Therefore, in this perspective, we provide an update on the phytochemical profiling analysis of this plant, as well as the relationships of specific biological and pharmacological effects of specific phytochemicals. Currently, among the organic solvents, ethanol reveals the highest effectiveness for the solvent extraction of precious components (mainly rosmarinic acid). Additionally, our attention is devoted to current developments in the extraction and fractionation of the phytochemicals of M. officinalis, highlighting the ongoing progress of the main strategies that the research community has employed. Finally, after analyzing the literature, we suggest potential perspectives in the field of sustainable extraction and purification of the phytochemical present in the plant. For instance, some research gaps concern the application of cavitation-assisted extraction processes, which can effectively enhance mass transfer while reducing the particle size of the extracted material in situ. Meanwhile, membrane-assisted processes could be useful in the fractionation and purification of obtained extracts. On the other hand, further studies should include the application of ionic liquids and deep eutectic solvents (DES), including DESs of natural origin (NADES) and hydrophobic DESs (hDES), as extraction or fractionating solvents, along with new possibilities for effective extraction related to DESs formed in situ, assisted by mechanical mixing (mechanochemistry-based approach).

  • A piece of corporate finance
    • Katarzyna Kubiszewska
    • Jarosław Ziętarski
    2023 Pełny tekst

    The handbook presents the subject of financial liquidity and CVP analysis. The handbook uses different types of information: definitions of the issues; “real life” examples illustrating a given theoretical issue in practice; mathematical formulas necessary to calculate a certain value; types of method used. In addition to traditional resources such as drawings, diagrams, tables and photos, the handbook also includes resources of an interactive nature, e.g. answers to tasks.

  • A Probe into the Corrosion Behavior of a WE43B Magnesium Alloy in a Simulated Body Fluid using Dynamic Electrochemical Impedance Spectroscopy
    • Husnu Gerengi
    • Sergio Lorenzi
    • Moses Solomon
    • Paweł Ślepski
    • Marina Cabrini
    2023 JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE

    WE43B is one of the newest Mg alloys with practical application in biomedical implant technology. This work attempts to scrutinize the corrosion characteristics of WE43B alloy in a simulated body fluid (SBF) at a typical body temperature. The dynamic-electrochemical impedance spectroscopy with the capacity to track changes on surfaces in a dynamic corrosive system is used in combination with other classical techniques namely, linear polarization, EIS, and hydrogen evolution to track the corrosion pattern of the alloy in SBF for 24 h. The electrochemical results reveal a steady increase in the corrosion resistance of the alloy with immersion time reaching 1398 Ω cm2 at 24 h. This corroborates the hydrogen evolution results in which a declining trend in the corrosion rate with immersion time is observed. The corrosion rate of the alloy is in the range of 1.326-1.338 mm y−1 at 24 h. The results from the applied techniques are comparable. The surface analysis (scanning electron microscope, energy-dispersive x-ray spectroscopy, atomic force microscopy AFM) results conform with the results obtained from applied methods.

  • A Review: Applications of the Spectral Finite Element Method
    • Muhammad Bilal Hafeez
    • Marek Krawczuk
    2023 Pełny tekst ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING

    The Spectral Finite Element Technique (SFEM) has Several Applications in the Sciences, Engineering, and Mathematics, which will be Covered in this Review Article. The Spectral Finite Element Method (SFEM) is a Variant of the Traditional Finite Element Method FEM that Makes use of Higher Order Basis Functions (FEM). One of the most Fundamental Numerical Techniques Employed in the Numerical Simulation is the SFEM, which Outperforms Other Techniques in Terms of Faster Convergence, Reduced Difusion and Dispersion Errors, Simplicity of the Application as well as Shorter time of Computation. The Spectral Finite Element Technique Combines the Characteristics of Approximating Polynomials of Spectral Methods. The Approach to Discretizing the Examined Region Unique to the FEM is a mix of both Approaches. Combining These Techniques Enables Quicker (Spectral) Convergence of Solutions, Higher Approximation Polynomial Order, the Removal of Geometric Constraints on the Examined Areas, and much Lower Discretization Density Requirements. Spectral Element Methods used in Diferent Applications are Presented Along with a Statistical Overview of Studies During 2010–2022.

  • A Review of Hyperelastic Constitutive Models for Dielectric Elastomers
    • Amin Alibakhshi
    • Shahriar Dastjerdi
    • Mohammad Malikan
    • Victor Eremeev
    2023

    Dielectric elastomers are smart materials that are essential components in soft systems and structures. The core element of a dielectric elastomer is soft matter, which is mainly rubber-like and elastomeric. These soft materials show a nonlinear behaviour and have a nonlinear strain-stress curve. The best candidates for modelling the nonlinear behaviour of such materials are hyperelastic strain energy functions. Hyperelastic functions have been extensively used for modelling dielectric elastomer smart structures. This review paper introduces hyperelastic constitutive laws for modelling dielectric elastomers. For this purpose, first, a general scheme of hyperelastic models is expressed. Then, some well-known hyperelastic models are introduced. Finally, we review in detail the utilized hyperelastic models for different configurations of dielectric elastomers. Possible future works in this field are outlined eventually.

  • A review of methods of blood supply to organs of the gastrointestinal tract. State of art
    • Zieliński Jacek
    • Adam Bujnowski
    • Norbert Szram
    • Weronika Szczecińska
    • Jakub Woźniak
    • Sergii Girnyi
    • Michalina Ciosek
    • Magdalena Tulińska
    • Jerzy Wtorek
    2023 EJSO-EUR J SURG ONC

    The correct assessment of blood supply is essential to eliminate possible postoperative complications. Re-anastomosis of the gastrointestinal tract after its resection must be preceded by the analysis of blood supply to the anastomosed fragments. It is important that the blood supply assessment procedure is reliable but also non-absorbing and, if possible, short. It should also be possible to repeat the procedure due to the need to change the anastomosed part. If the blood supply to the tissues is incorrectly estimated and, as a result, an inappropriate anastomosis, e.g. of the intestine, postoperative complications may occur, which in their mildest stage necessitate corrective surgery, and in their worst stage may lead to serious consequences, including death of the patient.

  • A review of phase change materials and heat enhancement methodologies
    • Muhammad Saqib
    • Rafał Andrzejczyk
    2023 Pełny tekst Wiley Interdisciplinary Reviews-Energy and Environment

    Phase change materials (PCMs) are an efficient alternative to store and release heat at a specific range of temperature. Here PCMs and heat enhancement methodologies for PCM storage are reviewed. A short overview of PCMs and their applications is presented in addition to the progress during the last 10 years. Heat enhancement techniques, that is, extended surfaces, multiple and composite PCMs, and encapsulation techniques, are presented along with a statistical overview of studies during 2016–2021. The importance of various fin and storage tank geometries (extended surfaces) is discussed in detail. Advancement in the latest heat enhancement techniques such as use of nano-enhanced PCMs is presented. Recommendations for future research are provided.

  • A selectively reduced degree basis for efficient mixed nonlinear isogeometric beam formulations with extensible directors
    • Myung-Jin Choi
    • Roger Sauer
    • Sven Klinkel
    2023 Pełny tekst COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING

    The effect of higher order continuity in the solution field by using NURBS basis function in isogeometric analysis (IGA) is investigated for an efficient mixed finite element formulation for elastostatic beams. It is based on the Hu–Washizu variational principle considering geometrical and material nonlinearities. Here we present a reduced degree of basis functions for the additional fields of the stress resultants and strains of the beam, which are allowed to be discontinuous across elements. This approach turns out to significantly improve the computational efficiency and the accuracy of the results. We consider a beam formulation with extensible directors, where cross-sectional strains are enriched to avoid Poisson locking by an enhanced assumed strain method. In numerical examples, we show the superior per degree-of-freedom accuracy of IGA over conventional finite element analysis, due to the higher order continuity in the displacement field. We further verify the efficient rotational coupling between beams, as well as the path-independence of the results.

  • A Series of Novel 3D Coordination Polymers Based on the Quinoline-2,4-dicarboxylate Building Block and Lanthanide(III) Ions—Temperature Dependence Investigations
    • Dmytro Vlasyuk
    • Renata Łyszczek
    • Mazur Liliana
    • Agnieszka Pladzyk
    • Zbigniew Hnatejko
    • Przemysław Woźny
    2023 Pełny tekst MOLECULES

    A series of novel 3D coordination polymers [Ln2(Qdca)3(H2O)x]yH2O (x = 3 or 4, y = 0–4) assembled from selected lanthanide ions (Ln(III) = Nd, Eu, Tb, and Er) and a non-explored quinoline- 2,4-dicarboxylate building block (Qdca2 = C11H5NO4 2) were prepared under hydrothermal conditions at temperatures of 100, 120, and 150 C. Generally, an increase in synthesis temperature resulted in structural transformations and the formation of more hydrated compounds. The metal complexes were characterized by elemental analysis, single-crystal and powder X-ray diffraction methods, thermal analysis (TG-DSC), ATR/FTIR, UV/Vis, and luminescence spectroscopy. The structural variety of three-dimensional coordination polymers can be ascribed to the temperature effect, which enforces the diversity of quinoline-2,4-dicarboxylate ligand denticity and conformation. The Qdca2 ligand only behaves as a bridging or bridging–chelating building block binding two to five metal centers with seven different coordination modes arising mainly from different carboxylate group coordination types. The presence of water molecules in the structures of complexes is crucial for their stability. The removal of both coordinated and non-coordinated water molecules leads to the disintegration and combustion of metal–organic frameworks to the appropriate lanthanide oxides. The luminescence features of complexes, quantum yield, and luminescent lifetimes were measured and analyzed. Only the Eu complexes show emission in the VIS region, whereas Nd and Er complexes emit in the NIR range. The luminescence properties of complexes were correlated with the crystal structures of the investigated complexes.

  • A significance of multi slip condition for inclined MHD nano-fluid flow with non linear thermal radiations, Dufuor and Sorrot, and chemically reactive bio-convection effect
    • Bilal Ahmad
    • Muhammad Ozair Ahmad
    • Muhammad Farman
    • Ali Akgül
    • Muhammad Riaz
    2023 Pełny tekst South African Journal of Chemical Engineering

    The aim of this research is to discuss the significance of slip conditions for magnetized nanofluid flow with the impact of nonlinear thermal radiations, activation energy, inclined MHD, sorrot and dufour, and gyrotactic micro motile organisms over continuous stretching of a two-dimensional sheet. The governing equations emerge in the form of partial differential equations. Since the resultant governing differential equations are nonlinear, the partial differential equations are transformed into ordinary differential equations using a workable similarity transformation. By using the Bvp4c module of the MATLAB program, the simplified mathematical framework can be numerically solved. The computation of Coefficients of skin friction, Nusselt numbers, different patterns of velocity profiles, fluid temperature, and concentration profiles reveals the physical nature of this study. As compared to earlier investigations, it was found that the obtained results demonstrated high degrees of symmetry and precision. A decline observes in velocity for boosted values of MHD, inclination, and rotatory parameter. However thermal transportation increases by increasing brownien motion, thermophoresis, radiation and Sorrot effect. The study has significant application in heat control systems, food factories, thermal exchangers, biomechanics, biomedical engineering, and aero dynamical systems

  • A simplified approach to determine the expiration date of certified reference material based on the results of monitoring long-term stability
    • Chintankumar Padariya
    • Małgorzata Rutkowska
    • Piotr Konieczka
    2023 MICROCHEMICAL JOURNAL

    All components of the quality assurance (QA) system for measurement results depend heavily on certified reference materials (CRMs). There is a need for a comprehensive discussion of the stability study using the CRM statistical method. Monitoring involves periodic sampling and analysis of the CRM at predetermined intervals to continuously monitor stability without compromising its integrity. The obtained stability data is then subjected to statistical analysis, considering factors such as trends, variability, and acceptable limits. In this study, we propose a simplified approach as a linear trend to determine the expiration date of CRM. A case study is conducted using the application of the mentioned statistical approaches according to ISO GUIDE 35:2017 with the inclusion of a linear trend for four MODAS CRMs based on the total mercury (THg) content, which all met the positive criteria for each test and CRM. The proposed approach may be helpful when the requirements stated in section B.4.2 (NOTE 3) are not met of the ISO GUIDE 35:2017. Although the shelf-life is an estimated value, it is, therefore, possible to apply simplifications in the course of its determination. The linear trend analysis would serve an ideal role while accessing the long-term stability study of the CRMs.

  • A simplified method to assess the impact of ship-to-ship collision on the risk of tanker ship hull girder breaking accounting for the effect of ageing
    • Krzysztof Wołoszyk
    • Jakub Montewka
    • Floris Goerlandt
    2023 Pełny tekst

    One of the most critical structural failures is the exceedance of the ship hull girder’s ultimate strength, which may result in hull breaking, and subsequent severe consequences, including loss of life and property as well as environmental damage in case of an oil spill. A cause for such loss of structural continuity can be triggered by a collision with another vessel. In addition, the ageing mechanisms of the hull structure could increase this risk. However, the majority of models for damage risk dedicated to collision and grounding accidents do not sufficiently account for the ageing effect. Furthermore, current risk models usually only consider oil spills due to perforation of the ship side, neglecting the ensuing risks of hull girder breaking. Therefore, in the presented work, we propose a simplified method to assess the probability of exceedance of the hull girder’s ultimate strength of a tanker ship, accounting both for the impact of corrosion degradation and the loss of the part of the midship cross-section due to collision with another vessel. A case study of a VLCC tanker ship is analysed to demonstrate the proposed methodology. Further ensuing consequences related to a hull girder failure are briefly discussed. Finally, key conclusions are given, and future research directions are outlined.

  • A Simplified SVPWM Technique for Five-leg Inverter with Dual Three-phase Output
    • Dmytro Kondratenko
    • Arkadiusz Lewicki
    2023 Pełny tekst

    This article proposes a simplified space vector pulse-width modulation (SVPWM) technique five-leg inverter with dual three-phase output. An idea to fed the dual tree-phase machine by the multiphase voltage source inverters (VSIs) is not new. Dual- and multi-motor drive systems are widely used in the industry applications. The most popular fields are: electric vehicles (EVs) and traction systems. Moreover, the specific characteristic of the dual-drive systems allow to use them in the paper and textile production process. Mostly these solutions utilize carrier-based PWM (CBPWM) techniques for the output voltage generation, however the SVPWM techniques might be also used for this purpose. The main idea of this paper is to simplify the modulation process and obtain the similar algorithms complexity and execution times for the space-vector and carrier-based PWM techniques. The proposed SVPWM strategy allows to decrease the number of calculations at the initial stage of the algorithm. The output voltages for both loads/motors can be generated independently, with different frequencies and amplitudes. Simulation results were obtained using the PLECS software package. The experimental investigation with RL load were conducted as well. The carried tests proved the effectiveness of the proposed modulation strategy. All results are shown in this paper.

  • A Simplistic Downlink Channel Estimation Method for NB-IoT
    • Jarosław Magiera
    2023 Pełny tekst Applied Sciences-Basel

    This paper presents a downlink channel estimation method intended for a Narrowband Internet of Things (NB-IoT) access link. Due to its low computational complexity, this method is well suited for energy-efficient IoT devices, still providing acceptable reception quality in terms of signal-to-noise (SNR) performance. This paper describes the physical layer of NB-IoT within the scope of channel estimation, and also reviews existing channel estimation methods for OFDM signals. The proposed method, based on linear interpolation of channel coefficients, is described as a three-step procedure. Next, indicators of channel quality assessment, which may be determined without prior knowledge about the transmitted signal, are defined. Two variants of channel estimation, differing in the frequency domain processing, are evaluated to assess the significance of frequency selectivity in an NB-IoT downlink. The chosen method is compared with another method implemented in MATLAB LTE ToolboxTM. An analysis of the computation time is conducted, subsequently demonstrating the definite advantage of the proposed method.

  • A Study of Mutual Coupling Suppression between Two Closely Spaced Planar Monopole Antenna Elements for 5G New Radio Massive MIMO System Applications
    • Rao Aziz
    • Sławomir Kozieł
    • Leifur Leifsson
    • Stanisław Szczepański
    2023 Pełny tekst Electronics

    5G NR (new radio) introduces the concept of massive MIMO (multiple-input-multiple-output) technology, in which a larger number of antenna arrays are installed on the transceiver. Due to the increased number of antenna elements allocated close to each other (approximately at half-wavelength distance), mutual coupling becomes a serious problem leading to performance degradation of the MIMO communication system. In this communication, two different config-urations of closely-spaced antenna array elements are studied. In order to reduce the mutual coupling, a combination of a metamaterial-based frequency selective surface (FSS), a metallic strip, and a slot element in the ground plane, is examined. It has been found that the proposed technique significantly suppresses mutual coupling from –12dB to –25dB. Both designs are fab-ricated and experimentally validated. The simulation results are in good agreement with the measurements. The proposed mutual coupling reduction technique may be suitable for massive MIMO systems in the fifth-generation (5G) new radio applications.

  • A study on microcrack monitoring in concrete: discrete element method simulations of acoustic emission for non-destructive diagnostics
    • Magdalena Rucka
    • Magdalena Knak
    • Michał Nitka
    2023 Pełny tekst ENGINEERING FRACTURE MECHANICS

    The research is focused on the monitoring of fracture evolution in concrete beams under three-point bending using the acoustic emission technique and the discrete element method. The main objective of the study was to numerically and experimentally investigate the mechanism behind the generation of elastic waves during acoustic emission events and their interaction with micro- and macro-cracking in concrete beams under monotonic quasi-static loading. This was achieved through the development of a DEM model and numerical modelling of AE effects. An improved 4-phase DEM model of concrete including real mesostructured specimens and the ability to simulate aggregate breakage was introduced. The propagation of elastic waves, recorded in both laboratory experiments and numerical calculations, was given particular attention. The results showed the high suitability of the developed DEM model for monitoring crack initiation, development and propagation, as well as for supporting the interpretation of diagnostic results obtained by acoustic emission techniques.

  • A survey of automatic speech recognition deep models performance for Polish medical terms
    • Marta Zielonka
    • Wiktor Krasiński
    • Jakub Nowak
    • Przemysław Rośleń
    • Jan Stopiński
    • Mateusz Żak
    • Franciszek Górski
    • Andrzej Czyżewski
    2023

    Among the numerous applications of speech-to-text technology is the support of documentation created by medical personnel. There are many available speech recognition systems for doctors. Their effectiveness in languages such as Polish should be verified. In connection with our project in this field, we decided to check how well the popular speech recognition systems work, employing models trained for the general Polish language. For this purpose, we selected 100 words from the International Classification of Diseases dictionary, the Polish-language version of the International Statistical Classification of Diseases and Health Problems. The words were read into a microphone by five women and five men and also generated with a speech synthesizer using a male and a female voice. This resulted in 1,200 recordings tested with the following systems: Whisper, Google speech-to-text, and Microsoft Azure speech-to-text. The achieved word recognition performance is reflected by the calculated metrics: WER, WIL, Levenshtein distance, Jaccard distance, MER, and CER. Results show that the highest efficiency for most cases was obtained by Azure speech-to-text. However, none of the tested models is ready for voice-filling medical records, describing cases, or prescribing treatment, because the number of errors made when converting speech to text is too high.

  • A Web-GIS tool for diagnosing spatial orientation of young adults: design and evaluation of Geo-Survey
    • Marcin Kulawiak
    • Dominik Krajnik
    • Marta Czaplicka
    • Agnieszka Dawidowicz
    2023 Pełny tekst Scientific Reports

    Spatial orientation is the effectiveness with which one is able to assess the mutual location of objects relative to a point of reference or a system of coordinates. Traditionally, this ability has been evaluated through field navigation tests, which do not take into account the prevailing influence of free online maps and virtual walks on a person’s interpretation of space. In this context, this study presents a Web-GIS tool designed and developed to examine spatial orientation skills in the context of the used map type. The tool, named Geo-Survey, enables combination of survey questions with customized maps, providing users with a set of possible answer types. Moreover, using the unique concept of predefined answers, the tool attempts to automate the process of analysing research results. The tools’ performance is evaluated via assessing the spatial orientation skills of a group of young adults.

  • A Wideband Rotary-Joint-Free H-Plane Horn Antenna With 360° Steerable Radiation Pattern Using Gap Waveguide Technology
    • Ali Karami Horestani
    • Michał Mrozowski
    2023 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    Considering the limitations of electronically steerable antennas such as limited steering span, gain degradation for large steering angles, complexity, and cost, this article is focused on the design of a simple mechanically steerable H-plane horn antenna. It is shown that since there is no need for an electrical connection between the top and bottom sections of a gap waveguide (GWG), if a sectoral horn is properly designed and realized using this technology, the pattern of the antenna can be easily steered without a rotary joint. To demonstrate this concept, a rotary-joint-free H-plane horn antenna is designed, and its performance is predicted using EM simulations. The antenna offers a wide operating band covering almost the entire Ku-band and provides a full 360◦ continuous steering span. Additionally, the proposed antenna benefits from a constant gain over the full range of steering angles. This is in contrast to phased array antennas whose gain degrades when the main beam is steered away from the broadside. The proposed concept and computed characteristics are verified by the good agreement between the simulated and measured characteristics of the fabricated prototype

  • Ab initio chemical kinetics of Isopropyl acetate oxidation with OH radicals
    • Mohamed A. Abdel-Rahman
    • Mohamed F. Shibl
    • Abolfazl Shiroudi
    • Mohamed A. M. Mahmoud
    2023 Pełny tekst Green Chemistry Letters and Reviews

    Global reactivity descriptors of isopropyl acetate (IPA) and thermo-kinetic aspects of its oxidation via OH radicals have been studied. Transition state theory (TST) was utilized to estimate the bimolecular rate constants. Ten oxidation pathways have been investigated, and all of them are exothermic. The potential energy diagram has been sketched using different pre- and post-reactive complexes for all reaction pathways. Rate coefficient calculations were obtained directly by connecting the separated reactants with different transition states. The results indicate that the reaction of IPA with OH radicals occurs in the ground state rather than the excited state, and the rate constants obtained directly and from the effective approach are the same, which confirmed the accuracy of the estimated pre-reactive complexes and the reaction mechanism. Rate constants and branching ratios show that hydrogen atom abstraction from the iso C − H (C2 atom) bond is the most kinetically preferable route up to 1000 K, while at higher temperatures, H-atom abstraction from the out-of-plane CH3 group (C3 atom) became the most dominant route with high competition with that of the in-plane CH3 group (C4 atom).

  • About definition of modes and magnetosonic heating in a plasma’s flow: Especial cases of perpendicular and nearly perpendicular wave vector and magnetic field
    • Anna Perelomova
    2023 Pełny tekst CONTRIBUTIONS TO PLASMA PHYSICS

    Dynamics of hydrodynamic perturbations in a plasma depend strongly on an angle between the wave vector and equilibrium straight magnetic field. The case of perpendicular propagation is especial. There are only two (fast) magnetosonic modes since two (slow) ones degenerate into the stationary one with zero speed of propagation. This demands individual definition of wave modes by the links of hydrodynamic relations. These links are not limiting case of the relations in the case of non-zero angle. The nonlinear excitation of the entropy mode in the field of intense magnetosonic perturbations is also unusual. Bulk and shear viscosity and thermal conduction are considered as the damping mechanisms in a weakly nonlinear flow. The leading-order dynamic equation is derived which governs perturbation of density in the entropy mode. The links of magnetosonic perturbations and magnetosonic heating may be indicators of plasma-, geometry of a flow, damping coefficients and type of wave motion. The “almost resonant” character of magnetosonic heating excited by the slow magnetosonic wave in the course of nearly perpendicular wave propagation, is discussed.

  • Accelerated Parameter Tuning of Antenna Structures by Means of Response Features and Principal Directions
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2023 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    Popularity of numerical optimization has been steadily on the rise in the design of modern antenna systems. Resorting to mathematically rigorous parameter tuning methods is a matter of practical necessity as interactive techniques (e.g., parameter sweeping) are no longer adequate when handling several performance figures over multi-dimensional parameter spaces. The most common design scenarios involve local tuning since decent initial designs are often rendered at the early phases of the design process. Notwithstanding, antenna optimization is usually executed using full-wave electromagnetic (EM) simulation tools, inevitably requiring considerable amount of computational resources. This paper introduces a novel technique for expedited gradient-based antenna optimization with numerical derivatives. The two major acceleration mechanisms, both of which exploit the problem-specific knowledge carried by the antenna characteristics, include the response feature methodology and sparse sensitivity updates restricted to selected principal vectors. The former permits flattening the landscape of the objective function, whereas the latter effectively reduces the problem dimensionality to dimensions that have the most significant effect on antenna characteristics, which are established using an automated decision-making procedure. Our methodology is applied to optimize three antenna structures. Comparisons with several benchmark procedures indicate the relevance of the adopted mechanisms and considerable computational savings that can be achieved. The average savings amount to 50 percent over conventional trust-region gradient search, and slightly lower, yet still significant, over accelerated versions thereof.

  • Acceleration of Electromagnetic Simulations on Reconfigurable FPGA Card
    • Tomasz Topa
    • Artur Noga
    • Tomasz Stefański
    2023

    In this contribution, the hardware acceleration of electromagnetic simulations on the reconfigurable field-programmable-gate-array (FPGA) card is presented. In the developed implementation of scientific computations, the matrix-assembly phase of the method of moments (MoM) is accelerated on the Xilinx Alveo U200 card. The computational method involves discretization of the frequency-domain mixed potential integral equation using the Rao-Wilton-Glisson basis functions and their extension to wire-to-surface junctions. Hardware resources in our FPGA card allow for synthesizing nine independent processing paths. The implementation is evaluated in a numerical test, which involves a simulation of radiation from a monopole antenna mounted on the roof of Dodge Shelby Charger car. Results show that the developed acceleration is 9.49× faster than a traditional (i.e., serial) central processing unit (CPU) MoM implementation, and about 1.66× faster than a parallel six-core CPU MoM implementation. However, in the considered numerical benchmark, the execution of the same computations on the hybrid CPU/FPGA platform reduces the power consumption 2.1× in comparison with the multicore implementation, hence, it allows for the reduction of environmental effects of scientific computing.

  • Accounting for the distributions of input quantities in the procedure for the measurement uncertainty evaluation when calibrating the goniometer
    • Igor Zakharov
    • Iryna Zadorozhna
    • Dariusz Świsulski
    • Dimitar Diakov
    2023 Pełny tekst Ukrainian Metrological Journal

    The discords concerning the measurement uncertainty evaluation in the Guide to the Expressing of Uncertainty in Measurement (GUM) and its Supplement 1 are considered. To overcome these discords, the authors of the paper propose to use the kurtosis method and the law of the propagation of the expanded uncertainty. Using the example of the goniometer calibration, the features of accounting for the distribution laws of input quantities in the procedure for the measurement uncertainty evaluation are shown. A model for direct measurements of the value of a reference measure of the angle using a goniometer is written, the procedures for the measurement uncertainty evaluation are described, and uncertainty budgets for each of the methods are given. An example of the measurement uncertainty evaluation when calibrating a digital goniometer using a 24-sided reference prism is described. An estimate of the expanded measurement uncertainty for this example was made based on the web-based software application NIST Uncertainty Machine, which showed a good agreement with the estimates obtained by the considered methods. The technology of applying this software application for the confidence level of 0,9545, which the software lacks, is shown. The estimates of the measurement uncertainty obtained by the proposed methods, Monte Carlo method and methodology of the Guide to the Expressing of Uncertainty in Measurement are compared.

  • Accurate electrothermal modelling of high frequency DC-DC converters with discrete IGBTs in PLECS software
    • Pawel Gorecki
    • Daniel Wojciechowski
    2023 Pełny tekst IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    In the paper, a novel, improved method of the IGBT junction temperature computations in the PLECS simulation software is presented. The developed method aims at accuracy of the junction temperature computations in PLECS by utilising a more sophisticated model of transistor losses, and by taking into account variability of transistor thermal resistance as a function of its temperature. A detailed description of the proposed method, as well as the parameter estimation procedure is given. The method is verified experimentally for the case of a DC-DC boost converter. Any discrepancies between simulations and measurements are discussed in detail. The proposed method is well suited for accurate electrothermal circuit-level simulations of power electronics converters.

  • Accurate Lightweight Calibration Methods for Mobile Low-Cost Particulate Matter Sensors
    • Per-Martin Jørstad
    • Marek Wójcikowski
    • Tuan-Vu Cao
    • Jean-Marie Lepioufle
    • Krystian Wojtkiewicz
    • Phuong Hoai Ha
    2023

    Monitoring air pollution is a critical step towards improving public health, particularly when it comes to identifying the primary air pollutants that can have an impact on human health. Among these pollutants, particulate matter (PM) with a diameter of up to 2.5 μ m (or PM2.5) is of particular concern, making it important to continuously and accurately monitor pollution related to PM. The emergence of mobile low-cost PM sensors has made it possible to monitor PM levels continuously in a greater number of locations. However, the accuracy of mobile low-cost PM sensors is often questionable as it depends on geographical factors such as local atmospheric conditions. This paper presents new calibration methods for mobile low-cost PM sensors that can correct inaccurate measurements from the sensors in real-time. Our new methods leverage Neural Architecture Search (NAS) to improve the accuracy and efficiency of calibration models for mobile low-cost PM sensors. The experimental evaluation shows that the new methods reduce accuracy error by more than 26% compared with the state-of-the-art methods. Moreover, the new methods are lightweight, taking less than 2.5 ms to correct each PM measurement on Intel Neural Compute Stick 2, an AI-accelerator for edge devices deployed in air pollution monitoring platforms.

  • AC-DC-DC Converter for Small Power Energy Storage Systems
    • Szymon Piasecki
    • Serafin Bachman
    • Jaroslaw Zaleski
    • Marek Jasinski
    • Marek Turzyński
    2023 Pełny tekst ENERGIES

    The energy transformation driven by the development of renewable energy sources has become a reality for all power grid users. Prosumer energy, primarily utilizing photovoltaic installations, is one of the fastest-growing market segments. The advancement of technology, a decrease in electrochemical energy storage prices, and changes in the legal framework governing energy billing for grid-fed power have led to a growing interest in expanding prosumer installations with energy storage modules. This article presents the authors’ concept and expected functionalities of a prosumer system equipped with energy storage based on theoretical assumptions, simulation analyses, and experimental research. Additionally, it covers the design and functionality of a hybrid converter; its experimental validation, including an analysis of operational modes; the development of a control algorithm under real conditions; and the efficiency testing of the device

  • Acoustic evaluation of road surfaces using different Close Proximity testing devices
    • Piotr Mioduszewski
    • Wojciech Sorociak,
    2023 APPLIED ACOUSTICS

    According to the valid standard, Close Proximity (CPX) method intends to evaluate the influence of road surfaces on traffic noise. Measurements may be carried out with the use of a self-powered vehicle or a special test trailer equipped with testing tyre towed by another vehicle. Two different testing devices took part in the research organized in Poland in order to determine the ranking of road surfaces in terms of acoustic parameters. Two tests (in the year 2018 and 2019) were carried out on 6 different road sections with different wearing courses. Road surfaces were ranked, which enabled comparison of the two measuring systems, based on the same standard. Obtained results revealed some differences within measured values ranging from about 1 dB to + 2 dB, which led to ranking changes concerning the best road surface in terms of limitation of traffic noise.

  • Activated persulfate and peroxymonosulfate based advanced oxidation processes (AOPs) for antibiotics degradation – A review
    • Zhila Honarmandrad
    • Xun Sun
    • Zhaohui Wang
    • Naushad Muhd
    • Grzegorz Boczkaj
    2023 Pełny tekst Water Resources and Industry

    Sulfate radical AOPs (SR-AOP) were successfully utilized in degradation of antibiotics in water and wastewater treatment. The review discusses details on SR-AOPs mechanisms and applications for antibiotics degradation. The progress in this field was discussed, highlighting the most promising developments and remaining challenges. The applicability of SR-AOPs was summarized revealing the most susceptible and persistent to oxidation groups of pharmaceuticals. Highest effectiveness was reported for degradation of pharmaceuticals on ppb level. Systems revealed a scavenging effect in case of oxidant dose 0.7mM of the PS and 2mM of PMS. Future development demands simple persulfates activation systems for real matrix treatment.

  • Activated sodium percarbonate-ozone (SPC/O3) hybrid hydrodynamic cavitation system for advanced oxidation processes (AOPs) of 1,4-dioxane in water
    • Kirill Fedorov
    • Manoj P Rayaroth
    • Noor Shah
    • Grzegorz Boczkaj
    2023 CHEMICAL ENGINEERING JOURNAL

    Hydrodynamic cavitation (HC) was employed to activate sodium percarbonate (SPC) and ozone (O3) to degrade recalcitrant 1,4-dioxane. The degradation efficiency > 99 % with a rate constant of 4.04 × 10−2 min−1 was achieved in 120 min under the optimal conditions of cavitation number (Cv) 0.27, pH 5, molar ratio of oxidant to pollutant (rox) 8, ozone dose of 0.86 g h−1 under 25 ± 2 °C with initial concentration of 1,4-dioxane 100 ppm. The application of HC with SPC/O3 increased the degradation efficiency by 43.32 % in 120 min, confirming a synergistic effect between the coupled processes. In addition, the degradation efficiency of 1,4-dioxane in HC/SPC/O3 was superior as compared to HC/H2O2/O3, suggesting that the presence of SPC has a significant role in degradation of 1,4-dioxane. Radical quenching experiment revealed highest contribution of hydroxyl (HOradical dot) radicals in the degradation of 1,4-dioxane among carbonate (CO3radical dot−) and superoxide (O2radical dot−) radicals. The presence of co-existing anions resulted in an inhibitory effect in the following order: SO42− > NO3− > Cl−. Based on GC–MS analysis, ethylene glycol diformate (EGDF) was detected as the main degradation product of 1,4-dioxane. The observed intermediate supports the radical route of 1,4-dioxane oxidation, which involves H-abstraction, ΔC-C splitting at the α-C position, subsequent dimerization, fragmentation and mineralization. Electric energy per order (EEO) for best process was 102.65 kWh·m−3·order−1. Total cost of treatment was estimated as approx. 12 USD/m3. These findings confirmed the SPC as an efficient, environmentally-friendly alternative to H2O2 and broadened the scope of HC-based AOPs for water and wastewater treatment.

  • Activated Tungsten Inert Gas Weld Characteristics of P91 Joint for Advanced Ultra Supercritical Power Plant Applications
    • Vishwa Bhanu
    • Dariusz Fydrych
    • Shailesh M. Pandey
    • Ankur Gupta
    • Chandan Pandey
    2023 JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE

    Activated Tungsten Inert Gas (A-TIG) welding, a variant of tungsten inert gas (TIG) welding, was used for welding P91. In Generation IV power plants, P91 welds are prone to premature failure due to the presence and formation of brittle phases and creep at high temperatures. When performing A-TIG welding, the flux composition plays a role in the reversal of the Marangoni flow in the weld pool, which ultimately determines the level of penetration achieved. A-TIG gave a complete penetration of 8 mm in the P91 weld. The weldment exhibited non-uniform growth of microstructures with varying grain sizes and precipitates, resulting in variation in mechanical properties. The weld fusion zone (WFZ) had a martensitic structure. The standard flat tensile test specimens were found to fail in the base metal and the fine-grain heat affected zone (FGHAZ) region. The sub-size flat tensile test specimen gave a high strength of 863 ± 10 MPa, failing in the WFZ. The high temperature tensile test specimens had the tensile strength of 512 ± 10 MPa (at 450 °C) and 469 ± 10 MPa (at 450 °C). In both the high temperature tensile test specimens, failure occurred in the base metal region. The impact toughness was recorded at 76 ± 15 Joules due to the presence of untempered martensite in the AW state, and in the PWHT state, the impact toughness increased up to 98 ± 15 Joules. In the AW state, the coarse grain heat affected zone (CGHAZ) region was observed with a maximum microhardness of 450 ± 5 HV and WFZ 460 ± 5 HV. The post-weld heat treatment (PWHT) was successfully performed to temper the martensite and impart some ductility to the weld. The A-TIG weld had sufficient benchmark strength, and the study successfully concluded its aim.

  • Activation of Metabotropic Glutamate Receptor (mGlu2) and Muscarinic Receptors (M1, M4, and M5), Alone or in Combination, and Its Impact on the Acquisition and Retention of Learning in the Morris Water Maze, NMDA Expression and cGMP Synthesis
    • Joanna M. Wierońska
    • Paulina Cieślik
    • Grzegorz Burnat
    • Leszek Kalinowski
    2023 Pełny tekst Biomolecules

    The Morris water maze (MWM) is regarded as one of the most popular tests for detecting spatial memory in rodents. Long-term potentiation and cGMP synthesis seem to be among the crucial factors involved in this type of learning. Muscarinic (M1, M4, and M5 receptors) and metabotropic glutamate (mGlu) receptors are important targets in the search for antipsychotic drugs with the potency to treat cognitive disabilities associated with the disorder. Here, we show that muscarinic receptor activators (VU0357017, VU0152100, and VU0238429) and an mGlu2 receptor activator, LY487379, dose-dependently prevented the development of cognitive disorders as a result of MK-801 administration in the MWM. The dose-ranges of the compounds were as follows: VU0357017, 0.25, 0.5, and 1 mg/kg; VU0152100, 0.05, 0.25, and 1 mg/kg; VU0238429, 1, 5, and 20 mg/kg; and LY487379, 0.5, 3, and 5 mg/kg. The co-administration of LY487379 with each of the individual muscarinic receptor ligands showed no synergistic effect, which contradicts the results obtained earlier in the novel object recognition (NOR) test. MWMlearning resulted in increased cGMP synthesis, both in the cortex and hippocampi, when compared to that in intact animals, which was prevented by MK-801 administration. The investigated compounds at the highest doses reversed this MK-801-induced effect. Neither the procedure nor the treatment resulted in changes in GluN2B-NMDA expression.

  • Active Control of Highly Autocorrelated Machinery Noise in Multivariate Nonminimum Phase Systems
    • Michał Meller
    • Adam Lasota
    2023 Pełny tekst CIRCUITS SYSTEMS AND SIGNAL PROCESSING

    In this paper, a novel multivariate active noise control scheme, designed to attenuate disturbances with high autocorrelation characteristics and preserve background signals, is proposed. The algorithm belongs to the class of feedback controllers and, unlike the popular feedforward FX-LMS approach, does not require availability of a reference signal. The proposed approach draws its inspiration from the iterative learning control and repetitive mode control methods, and employs a modified inverse model learning law. The classical inverse model learning law is well known to offer fast convergence and high steady-state performance, provided that the secondary path is minimum phase and well known. The proposed modified inverse model learning law employs a spectral factorization trick, which allows one to use the method with nonminimum phase plants of arbitrary order. Moreover, our scheme includes a controller bandwidth limiting mechanism that can be used to tune the disturbance rejection bandwidth and to improve the closed-loop robustness to errors in the model of the secondary path. The algorithm’s behavior and performance are verified with computer simulations that demonstrate suppression of electrical transformer noise and include realistic models of the secondary path. The results show high-level selective attenuation and fast convergence.

  • Adapting education to a changing climate: preparing architecture students for climate-resilient design
    • Izabela Burda
    • Jakub Kołodziejczak
    2023 Pełny tekst World Transactions on Engineering and Technology Education

    In this article, the authors explore the connection between climate change and the fields of architecture and urban planning. With the increasing frequency of flooding and extreme weather events, the built environment is confronting challenges in terms of sustainability and resilience. To meet these problems, it is necessary to prepare various specialists to assume responsibility for making future decisions. The authors of this article examine whether students in the Faculty of Architecture at Gdańsk University of Technology, Poland, are well-prepared for the posed challenges. For that purpose, a survey was undertaken to gather the students’ viewpoints on the roles of architecture and urban planning in addressing climate change and their expectations concerning the coverage of this topic in their studies. The authors also analyse the methods used in the architectural education that facilitate an understanding of the interaction between climate change and the evolving urban landscape. Furthermore, they indicate the issues that should be incorporated into the curriculum to enhance students’ ability to create under changing climatic conditions.

  • Adaptive Dynamical Systems Modelling of Transformational Organizational Change with Focus on Organizational Culture and Organizational Learning
    • Lars Rass
    • Jan Treur
    • Wioleta Kucharska
    • Anna Monika Wiewiora
    2023 Pełny tekst Cognitive Systems Research

    Transformative Organizational Change becomes more and more significant both practically and academically, especially in the context of organizational culture and learning. However computational modeling and a formalization of organizational change and learning processes are still largely unexplored. This paper aims to provide an adaptive network model of transformative organizational change and translate a selection of organizational learning and change processes into computationally modeled processes. Additionally, it sets out to connect the dynamic systems view of organizations to self-modelling network models. The creation of the model and the implemented mechanisms of organizational processes are based on extrapolations of an extensive literature study and grounded in related work in this field, and then applied to a specified hospital-related case scenario in the context of safety culture. The model was evaluated by running several simulations and variations thereof. The results of these were investigated by qualitative analysis and comparison to expected emergent behaviour based on related available academic literature. The simulations performed confirmed the occurrence of an organizational transformational change towards a constant learning culture by offering repeated and effective learning and changes to organizational processes. Observations about various interplays and effects of the mechanism have been made, and they exposed that acceptance of mistakes as a part of learning culture facilitates transformational change and may foster sustainable change in the long run. . Further, the model confirmed that the self-modelling network model approach applies to a dynamic systems view of organizations and a systems perspective of organizational change. The created model offers the basis for the further creation of self-modelling network models within the field of transformative organizational change and the translated mechanisms of this model can further be extracted and reused in a forthcoming academic exploration of this field.

  • Adaptive stochastic and hybrid nonlinear optimization algorithms for improving the effectiveness of the biological processes at WWTP
    • Robert Piotrowski
    • Krzysztof Milewski
    • Bartosz Maciąg
    2023 BIOCHEMICAL ENGINEERING JOURNAL

    Wastewater treatment plays an important factor in the modern world. Insufficient treatment may result in environmental pollution which can further lead to disasters and diseases. However, processes that take place inside wastewater treatment plants (WWTP) are highly complex in nature, therefore it is difficult to design an efficient, optimal control system. The problem regarding biochemical reactions inside Sequential Batch Reactor (SBR) is analyzed in this paper and the optimization problem is defined. Next, chosen optimization methods including both deterministic and metaheuristic algorithms are carefully described. Series of simulation experiments are conducted based on a verified model of SBR from Swarzewo Wastewater Treatment Plant (WWTP) - Northern Poland. The proposed optimal control system allowed to increase the efficiency, improve the quality of outflow (reduction of Chemical Oxygen Demand (COD), total nitrogen (Ntot) and total phosphorus (Ptot)) and reduce wastewater treatment costs.

  • Adaptive Wavelet-Based Correction of Non-Anechoic Antenna Measurements
    • Adrian Bekasiewicz
    • Vorya Waladi
    • Marek Wójcikowski
    • Tom Dhaene
    2023 Pełny tekst

    Non-anechoic measurements represent an affordable alternative to evaluation of antenna performance in expensive, dedicated facilities. Due to interferences and noise from external sources of EM radiation, far-field results obtained in non-ideal conditions require additional post-processing. Conventional correction algorithms rely on manual tuning of parameters, which make them unsuitable for reliable testing of prototypes. In this work, a wavelet-based correction method with an adaptively adjusted setup has been proposed. The performance of the presented framework has been demonstrated using an electrically small monopole antenna evaluated in the non-anechoic test site (here, a regular office room). The method has been favorably compared against the existing techniques from the literature.

  • Addressing Challenges in AI-based Systems Development: A Proposal of Adapted Requirements Engineering Process
    • Kamil Jabłoński
    • Aleksander Jarzębowicz
    2023 Pełny tekst

    [Context] Present-day IT systems are more and more dependent on artificial intelligence (AI) solutions. Developing AI-based systems means facing new challenges, not known for more conventional systems. Such challenges need to be identified and addressed by properly adapting the existing development and management processes. [Objective] In this paper, we focus on the requirements engineering (RE) area of IT projects and aim to propose the RE process that would be able to address at least some of the reported challenges. No proposal of such process could be found in the existing literature. [Method] We conducted a literature review using a snowballing technique to identify RE-related challenges for AI-based systems. Then, we compared several RE industry guides, selected a well-established RE process and adapted it by introducing additional practices. The additional practices were proposed as result of brainstorming and ideation process. [Results] The contributions of this paper include: a list of identified challenges, a set of additional practices to mitigate challenges and a model of the adapted RE process which integrates such practices. [Conclusions] The proposed process is available for validation activities and can be used by researchers and practitioners as a base for further adaptations of RE approaches to AI solutions.

  • Advanced fatigue and rutting characterisation of Polish asphalt mixtures based on the VECD model and viscoplastic shift model
    • Sara Spadoni
    • Lorenzo Paolo Ingrassia
    • Piotr Jaskuła
    • Francesco Canestrari
    2023 Road Materials and Pavement Design

    The advanced asphalt mixture performance-related specifications (AM-PRS) recently developed in USA can allow an optimisation of the design process of asphalt pavements thanks to the possibility to fully take into account the intrinsic material properties. In this study, four typical Polish mixtures, i.e. a Stone Mastic Asphalt (SMA) for wearing course, two mixtures for binder course with neat bitumen or Polymer modified Bitumen (PmB), and a mixture for asphalt base course with neat bitumen, were investigated by applying such advanced framework. The fatigue performance was studied through the simplified viscoelastic continuum damage (S-VECD) approach, whereas the rutting properties were assessed through the viscoplastic theory of the shift model. The findings were consistent with the composition of the studied mixtures, demonstrating the reliability and applicability of the AM-PRS even for typical Polish mixtures. Specifically, the high amount of soft PmB made the SMA mixture tough against fatigue cracking, but also more prone to rutting. The two binder mixtures exhibited good performance against both fatigue and rutting, and the polymer modification improved the toughness and increased the stiffness at high temperatures. The base mixture is expected to suffer fatigue cracking more than rutting, likely due to the low amount of bitumen and coarser aggregate gradation. These results can be used in the future for pavement performance predictions with FlexPAVETM software programme to ultimately optimise the design of Polish pavements.

  • Advanced numerical modelling for predicting residual compressive strength of corroded stiffened plates
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    2023 Pełny tekst THIN-WALLED STRUCTURES

    An advanced methodology for predicting the residual compressive strength of corroded stiffened plates is developed here using the non-linear finite element method. The non-uniform loss of a plate thickness is accounted for on a macro-scale. In contrast, mechanical properties are changed using the constitutive model to reflect the corrosion degradation impact on a micro-scale. Three different stiffened plate thicknesses are considered, and ultimate compressive capacity is analysed for different severity of corrosion degradation. First, the deterministic analysis is performed, and numerical results are validated against the experiment. Then, the corrosion fields are modelled with the use of random fields. Different statistical characteristics of the generated random fields are investigated to identify their impact on the resulting structural behaviour. It was found that severe corrosion degradation could cause an excessive reduction of structural capacity even at 50%. Finally, the results of the present study are compared with the already studied corrosion models showing a highly non-conservative solution of the latter, where the plate thickness is reduced only due to the corrosion degradation progress.