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Recent items
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Microstructure and mechanical properties of a dissimilar metal welded joint of Inconel 617 and P92 steel with Inconel 82 buttering layer for AUSC boiler application
- Amit Kumar
- Sachin Sirohi
- Manohar Singh
- Dariusz Fydrych
- Chandan Pandey
The application of the novel dissimilar metal welded (DMW) joint, utilizing Inconel 617 and P92 steel, was showcased in the advanced ultra-supercritical (AUSC) boiler. The work has been performed to investigate the effect of Inconel 82 (ERNiCr-3) buttering layer on microstructure and mechanical properties (high-temperature tensile strength, impact strength and microhardness) of gas tungsten arc welded (GTAW) dissimilar joint between Inconel 617 and P92 steel fabricated using the Inconel 617 (ERNiCrCoMo-1) filler. For optical microscopy and scanning electron microscopy (SEM), samples were machined along a transverse direction which comprised the butter layer, weld metal, and heat-affected zone of both sides. The energy-dispersive X-ray spectroscopy (EDS) was used to map the interface of the buttering layer and weld metal and butter layer and P92 steel. The high-temperature tensile testing and Charpy impact testing at room temperature were conducted for the integrity assessment of the welded joint. The examination of microstructure and hardness revealed that the buttering layer of Inconel 82 filler successfully mitigated a significant portion of the brittle martensitic microstructure from the coarse-grained heat-affected zone (CGHAZ), along with hardness peaks on the side of P92 steel. The conventional method of DMW joint fabrication, without the use of a buttering layer, has been demonstrated to be less favourable compared to the new fabrication method, which incorporates a buttering layer. The TiC/NbC carbides were identified in the Inconel 82 buttering layer, whereas M23C6 and Mo6C carbides were found in the Inconel 617 filler weld. Near the interface of the Inconel 82 buttering layer and P92 steel, the formation of peninsula and island structures, as well as Type I and Type II boundaries, were confirmed. Additionally, element diffusion of Ni, Cr, and Fe was observed. The tensile test results indicated an ultimate tensile strength of 620 ± 4 MPa and % elongation of 19 ± 4 % at room temperature, with fracture occurring in the buttering layer near the interface of the buttering layer and P92 steel. At temperatures of 550 °C and 650 °C, the ultimate tensile strength decreased to 448 MPa and 326 MPa, respectively, with fractures occurring in the P92 steel, irrespective of temperature. The hardness of the Inconel 82 buttering layer and Inconel 617 filler weld were 219 ± 10 HV and 248 ± 11 HV, respectively.
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Mieszanki betonowe stosowane w technologii druku trójwymiarowego
- Andrzej Ambroziak
W niniejszej pracy dokonano przeglądu literatury z zakresu mieszanek i zapraw betonowych stosowanych w druku trójwymiarowym. Przegląd literatury przygotowano z zachowaniem chronologii pojawienia się danej publikacji (daty publikacji). Na podstawie przeprowadzonego przeglądu dokonano tabelarycznego zestawienia receptur mieszanek wykorzystywanych w wydrukach trójwymiarowych (3D). Przedstawiony przegląd literatury z zakresu mieszanek i zapraw betonowych stosowanych w druku trójwymiarowym można traktować jako wstęp do szczegółowych badań związanych z projektowaniem nowych typów mieszanek i receptur.
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Migration of trace elements and radioisotopes to various fractions of solid wastes generated as a result of the sewage sludge incineration process
- Oskar Ronda
- Bartłomiej Cieślik
- Barbara Piotrowska
- Krzysztof Isajenko
- Satoki Okabayashi
- Koichi Chiba
- Motohiro Tsuboi
- Justyna Płotka-Wasylka
The research was aimed at providing new knowledge in the field of chemical characteristics of solid waste generated in the process of combustion of sewage sludge in fluidized bed furnaces. The research material consisted of disposed fluidized beds (DFB), sewage sludge ash (SSA) and air pollution control residues (APC) from three Polish installations for the thermal treatment of sewage sludge. Natural radionuclides as well as anthropogenic isotope 137Cs were determined in the tested materials and the migration of a wide spectrum of trace elements to various waste fractions generated in the process of sewage sludge combustion was examined. It was observed that both radioisotopes and most of the trace elements determined accumulate in SSA and DFB, while the APC fraction contains a much smaller amount of them. The exceptions are mercury and selenium, whose volatile compounds migrate to the exhaust gas dedusting system and accumulate in the APC fraction (up to 40 mg/kg and 13 mg/kg, respectively). A potential threat from the 226Ra isotope in SSA is identified in the context of the management of this waste in the production of building materials because the typical activity of 226Ra in SSA collected from areas with very low Ra content in natural environment exceeds 1.5–6 times the activity of this isotope in conventional cement mixtures. When managing SSA and DFB, special attention should be paid to the content of metalloids such as As, B and Se, due to the high content of mobile forms of these elements in the mentioned materials.
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Millimeter Wave Negative Refractive Index Metamaterial Antenna Array
- Rao Aziz
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
In this paper, a novel negative refractive index metamaterial (NIM) is developed and characterized. The proposed metamaterial exhibits negative effective permittivity (εeffe) and negative effective permeability (µeffe) at millimeter wave frequency of 28GHz. This attractive feature is utilized to enhance the gain of a microstrip patch antenna (MPA). Two thin layers of 5 5 subwavelength unit cell array of NIM are placed above a single MPA to enhance the gain of the antenna. Each unit cell has an area of 3.4 3.4 mm2. A gain increase of 7.9dBi has been observed when using the proposed NIM as a superstrate. Furthermore, the NIM array is placed over a 2 2 array of MPAs with four ports to demonstrate versatility of the metamaterial. The total size of the 2 2 antenna array system with N-MTM is about 61.1 34 16mm3 (5.71λ 3.18λ 1.5λ, where λ is the free-space wavelength at 28 GHz). The measurement result indicate that the maximum gain of the antenna array is 13.5dBi. A gain enhancement of 7.55 dB in E-Plane and 7.25 dB in H-Plane at the resonant frequency of 28 GHz is obtained. The proposed antenna structure is suitable for 5G millimeter wave communications, in particular, for possible implementation in future millimeter wave access points and cellular base stations.
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Miniaturization-Oriented Design of Spline-Parameterized UWB Antenna for In-Door Positioning Applications
- Adrian Bekasiewicz
- Tom Dhaene
- Ivo Couckuyt
- Jacek Litka
Design of ultra-wideband antennas for in-door localization applications is a challenging task. It involves development of geometry that maintains appropriate balance between the size and performance. In this work, a topologically-flexible monopole has been generated using a stratified framework which embeds a gradient-based trust-region (TR) optimization algorithm in a meta-loop that gradually increases the structure dimensionality. The optimization has been performed using a composite objective function that maintains acceptable size/performance trade-off. The final design features a reflection below –10 dB within the UWB spectrum and a small footprint of only 182 mm2. The considered method has been benchmarked against a standard TR-based routine executed directly on a multi-dimensional electromagnetic model of the antenna.
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Minimization of a ship's magnetic signature under external field conditions using a multi-dipole model
- Mirosław Wołoszyn
- Jarosław Tarnawski
The paper addresses the innovative issue of minimizing the ship's magnetic signature under any external field conditions, i.e., for arbitrary values of ambient field modulus and magnetic inclination. Varying values of the external field, depending on the current geographical location, affect only the induced part of ship's magnetization. A practical problem in minimizing the ship signature is separating permanent magnetization from induced magnetization. When the ship position changes, a signature measurement has to be made under new magnetic field conditions to update the currents in the coils. This is impractical or even difficult to do (due to the need for a measuring ground), so there is a need to predict the ship's magnetization value in arbitrary geographical location conditions based on the reference signature determined on the measuring ground. In particular, the model predicting the signatures at a new geographical location must be able to separate the two types of magnetization, as permanent magnetization is independent of external conditions. In this paper, a FEM model of the vessel is first embedded in an external field and permanent magnetization is simulated using DC coils placed inside the model. Then, using the previously developed rules for data acquisition and determination of model parameters, a multi-dipole model is synthesized in which the induced and permanent parts are separated. The multi-dipole model thus developed has been successfully confronted with the initial model in FEM environment. The separation of permanent and induced magnetization allows the latter to be scaled according to new values of the external field. In the paper, the situation of determining a signature at one geographical position and its projection onto two other positions is analyzed. Having determined the signature with a high degree of accuracy anywhere in the world, it is possible to perform classical signature minimization by determining DC currents in coils placed inside the ship's hull. The paper also analyzes the effectiveness of ship's signature minimization and the influence of ship's course on the signature value. The advantage of the method presented in this paper is an integrated approach to the issue of scaling and minimization of ship magnetic signature, which has not been presented in the literature on such a scale before.
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M-integral for finite anti-plane shear of a nonlinear elastic matrix with rigid inclusions
- Victor Eremeev
- Konstantin Naumenko
The path-independent M-integral plays an important role in analysis of solids with inhomogeneities. However, the available applications are almost limited to linear-elastic or physically non-linear power law type materials under the assumption of infinitesimal strains. In this paper we formulate the M-integral for a class of hyperelastic solids undergoing finite anti-plane shear deformation. As an application we consider the problem of rigid inclusions embedded in a Mooney–Rivlin matrix material. With the derived M-integral we compute weighted averages of the shear stress acting on the inclusion surface. Furthermore, we prove that a system of rigid inclusions can be replaced by one effective inclusion.
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Missing Puzzle Pieces in Dementia Research: HCN Channels and Theta Oscillations
- Paulina Kaźmierska-Grębowska
- Maciej Jankowski
- Bruce M. MacIver
Increasing evidence indicates a role of hyperpolarization activated cation (HCN) channels in controlling the resting membrane potential, pacemaker activity, memory formation, sleep, and arousal. Their disfunction may be associated with the development of epilepsy and age-related memory decline. Neuronal hyperexcitability involved in epileptogenesis and EEG desynchronization occur in the course of dementia in human Alzheimer’s Disease (AD) and animal models, nevertheless the underlying ionic and cellular mechanisms of these effects are not well understood. Some suggest that theta rhythms involved in memory formation could be used as a marker of memory disturbances in the course of neurogenerative diseases, including AD. This review focusses on the interplay between hyperpolarization HCN channels, theta oscillations, memory formation and their role(s) in dementias, including AD. While individually, each of these factors have been linked to each other with strong supportive evidence, we hope here to expand this linkage to a more inclusive picture. Thus, HCN channels could provide a molecular target for developing new therapeutic agents for preventing and/or treating dementia.
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Mixed, quantum-classical description of electron density transfer in the collision process
- Paweł Wojda
- Marta Łabuda
- Sergey Kshevetskii
In this work, we investigate an ion-atom model describing the time-dependent evolution of electron density during the collision. For a S3+- H system, numerical simulations are based on classical trajectory calculations, and the electron density behaviour is described with the time-dependent Schrödinger equation. We apply the finite difference method to obtain quantitative insights into the charge transfer dynamics, providing detailed information about the spatial and temporal evolution of the collision process. The results are given for representative examples of the collision, from eV to keV range of energies, in head-on collision as well as for different values of impact parameter. A validity and precision of the proposed model and interpretation of the particle collision in terms of eigenstates are also discussed.
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Mixed-use buildings as the basic unit that shapes the housing environment of smart cities of the future
- Mateusz Gerigk
The contemporary approach to creating the residential function is confronted with the trend of increasing the volume of buildings and expectations regarding the future urban environment focused on sustainable development. This paper presents an overview of the residential structure in the context of defined thematic scopes. Namely, it is a systemic approach to the problem of designing mixed-use buildings which create a modern residential structure in developing urban centres. The creation of smart cities from existing urban areas and newly designed centres involves comprehensively defined design guidelines. The key is the integrity and interoperability of the dynamic structure which can serve as a basis for developing new systems and/or improving the existing ones. The developed model structure for creating and maintaining the system is based on a genetic algorithm and is presented in the form of a neural network that involves the use of artificial intelligence (AI). The specific structure is intended as a tool to support supervision and decision-making in the process of designing and managing contemporary mixed-use buildings in their newly planned surroundings.
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Mobilenet-V2 Enhanced Parkinson's Disease Prediction with Hybrid Data Integration
- Sameer Ahmad Bhat
- Piotr Szczuko
This study investigates the role of deep learning models, particularly MobileNet-v2, in Parkinson's Disease (PD) detection through handwriting spiral analysis. Handwriting difficulties often signal early signs of PD, necessitating early detection tools due to potential impacts on patients' work capacities. The study utilizes a three-fold approach, including data augmentation, algorithm development for simulated PD image datasets, and the creation of a hybrid dataset. MobileNet-v2 is trained on these datasets, revealing higher generalization or prediction accuracy of 84% with hybrid datasets. Future research will explore the impact of high variability synthetic datasets on prediction accuracies and investigate the MobileNet-v2 architecture's memory footprint for timely inferences with low latency
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Model Management for Low-Computational-Budget Simulation-Based Optimization of Antenna Structures Using Nature-Inspired Algorithms
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
The primary objective of this study is investigation of the possibilities of accelerating nature-inspired optimization of antenna structures using multi-fidelity EM simulation models. The primary methodology developed to achieve acceleration is a model management scheme which the level of EM simulation fidelity using two criteria: the convergence status of the optimization algorithm, and relative quality of the individual designs within the solution pool. The search process is initiated using the lowest-fidelity (therefore, the fastest) EM model. The fidelity is step-by-step increased towards the conclusion of the process. At the same time, lower-quality designs are evaluated at lower resolution level as compared to the better ones. Our technique has been extensively validated using several microstrip antennas, and particle swarm optimization (PSO) algorithm as the search engine. The obtained results demonstrate that making the EM model fidelity dependent on just the convergence status of the algorithm allows for relative savings from forty to seventy percent, depending on the algorithm setup. At the same time, managing model fidelity as a function of both convergence status and relative design quality (within the population processed by the algorithm) allows for up to 85 percent savings, as compared to high-fidelity-based algorithms. Furthermore, the achieved acceleration is not detrimental to the optimization process reliability. Apart from the computational efficiency, the attractive feature of the proposed approach is implementation simplicity and versatility: the presented management scheme can be readily incorporated into most nature-inspired routines.
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Model oceny dojrzałości przedsiębiorstw do zastosowania zwinnych metodyk zarządzania projektami IT
- Piotr Zejer
Dysertacja koncentruje się na budowie modelu, który ocenia gotowość przedsiębiorstw do wdrożenia zwinnych metodyk zarządzania projektami IT. Analizuje istniejące metody oceny dojrzałości projektowej i wprowadza własny model, biorąc pod uwagę krytyczne czynniki sukcesu i skuteczność zwinnych metod. Rozprawa zawiera badania literaturowe, empiryczne studium przypadku oraz weryfikację i rekomendacje modelu, dostarczając wglądu w praktyczne zastosowanie zwinnych metod zarządzania projektami w sektorze IT. Głównym celem modelu jest wskazanie uwarunkowań i obszarów funkcjonalnych przedsiębiorstwa, które wymagają poprawy dla skutecznego stosowania tych metod. Praca dostarcza praktycznego narzędzia dla organizacji, umożliwiającego ocenę ich dojrzałości w kontekście zwinnych praktyk zarządzania projektami, co ma kluczowe znaczenie dla sukcesu projektów IT w dynamicznie zmieniającym się środowisku biznesowym.
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Model Pomorskiej Nagrody Jakości w świetle wyników badań opinii stron zainteresowanych
- Anna Wendt
- Piotr Grudowski
Cel - prezentacja oryginalnego modelu wykorzystywanego do oceny/samooceny organizacji w regionalnym konkursie o Pomorską Nagrodę Jakości na podstawie oceny dotychczasowych doświadczeń oraz badania opinii i potrzeb głównych interesariuszy tej inicjatywy. Podstawowym założeniem przy opracowaniu tego modelu jest jego dostosowanie do współczesnych trendów dotyczących doskonałości organizacyjnej oraz upowszechnienie jego stosowania jako obiektywnej podstawy ewaluacji skuteczności i efektywności organizacji prywatnych i publicznych. Projekt badania, metodyka badawcza, koncepcja - na podstawie integracyjnego przeglądu literatury określono cel opracowania. Dla osiągnięcia tego celu przeprowadzono badania empiryczne, które wykorzystują studium przypadku (case study) konkursów o Pomorską Nagrodę Jakości. W tym kontekście zastosowano metody badań jakościowych takie jak ustrukturyzowane wywiady bezpośrednie, analizę materiałów źródłowych oraz obserwacje uczestniczące. Wyniki/ wnioski - uczestnicy konkursów pozytywnie ocenili proces organizacji konkursu. Dostrzegali jednak problemy związane z wykorzystaniem arkusza samooceny. Były to m.in. zbyt duża pracochłonność związana z wypełnianiem arkusza przez uczestników konkursu oraz niezrozumienie zawartych w nim stwierdzeń i pojęć. Uwagi te potwierdzili także organizatorzy konkursu. W związku z aktualizacją Modelu EFQM, na którego założeniach i zasadach opierały się stosowane dotąd kryteria konkursowe, postanowiono uaktualnić Model Pomorskiej Nagrody Jakości. W tym celu wykorzystano Model EFQM w wersji z roku 2020, aktualną wersję modelu CAF oraz wnioski z przeprowadzonych przez autorów badań jakościowych. Opracowano nową wersję kwestionariusza samooceny oraz dostosowano skalę ocen i punktację stanowiącą podstawę określenia wyników w konkursach. Zastosowanie praktyczne - opracowany w roku 2023 model oceny w ramach Pomorskiej Nagrody Jakości może być stosowany jako podstawa rozwoju systemu zarządzania organizacją. Ankieta samooceny jest narzędziem doskonalenia obejmującym wiele obszarów działalności organizacji. Sam udział w konkursie jest poświadczeniem wysokiego poziomu świadomości projakościowej organizacji oraz sprzyjać może wymianie dobrych praktyk na szczeblu regionalnym oraz krajowym i międzynarodowym.
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Modeling and Accuracy Assessment of Determining the Coastline Course Using Geodetic, Photogrammetric and Satellite Measurement Methods: Case Study in Gdynia Beach in Poland
- Francesco Giuseppe Figliomeni
- Mariusz Specht
- Claudio Parente
- Cezary Specht
- Andrzej Stateczny
The coastal environment represents a resource from both a natural and economic point of view, but it is subject to continuous transformations due to climate change, human activities, and natural risks. Remote sensing techniques have enormous potential in monitoring coastal areas. However, one of the main tasks is accurately identifying the boundary between waterbodies such as oceans, seas, lakes or rivers, and the land surface. The aim of this research is to evaluate the accuracy of coastline extraction using different datasets. The images used come from UAV-RGB and the Landsat-9 and Sentinel-2 satellites. The method applied for extracting the coast feature involves a first phase of application of the Normalized DifferenceWater Index (NDWI), only for satellite data, and consequent application of the maximum likelihood classification, with automatic vectorization. To carry out a direct comparison with the extracted data, a coastline obtained through a field survey using a Global Navigation Satellite System (GNSS) device was used. The results are very satisfactory as they meet the minimum requirements specified by the International Hydrographic Organization (IHO) S-44. Both the UAV and the Sentinel-2 reach the maximum order, called the Exclusive order (Total Horizontal Uncertainty (THU) of 5 m with a confidence level of 95%), while the Landsat-9 falls into the Special order (THU of 10 m with a confidence level of 95%).
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Modeling and Strength Calculations of Parts Made Using 3D Printing Technology and Mounted in a Custom-Made Lower Limb Exoskeleton
- Szczepan Śpiewak
- Wiktoria Wojnicz
- Jan Awrejcewicz
- Magdalena Mazur
- Michał Ludwicki
- Bartosz Stańczyk
- Bartłomiej Zagrodny
This study is focused on the application of 3D-printed elements and conventional elements to create a prototype of a custom-made exoskeleton for lower limb rehabilitation. The 3D-printed elements were produced by using Fused Deposition Modeling technology and acrylonitrile butadiene styrene (ABS) material. The scope of this work involved the design and construction of an exoskeleton, experimental testing of the ABS material and numerical research by using the finite element method. On the basis of the obtained results, it was possible to deduce whether the load-bearing 3D-printed elements can be used in the proposed mechanical construction. The work contains full data of the material models used in FEM modeling, taking into account the orthotropic properties of the ABS material. Various types of finite elements were used in the presented FE models. The work is a comprehensive combination of material testing issues with the possibility of implementing the obtained results in numerical strength models of machine parts.
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Modeling lignin extraction with ionic liquids using machine learning approach
- Karol Baran
- Beata Barczak
- Adam Kloskowski
Lignin, next to cellulose, is the second most common natural biopolymer on Earth, containing a third of the organic carbon in the biosphere. For many years, lignin was perceived as waste when obtaining cellulose and hemicellulose and used as a biofuel for the production of bioenergy. However, recently, lignin has been considered a renewable raw material for the production of chemicals and materials to replace petrochemical resources. In this context, an increasing demand for high-quality lignin is to be expected. It is, therefore, essential to optimize the technological processes of obtaining it from natural sources, such as biomass. In this work, an investigation of the use of machine learning-based quantitative structure-property relationship (QSPR) modeling for the preliminary processing of lignin recovery from herbaceous biomass using ionic liquids (ILs) is described. Training of the models using experimental data collected from original publications on the topic is assumed, and molecular descriptors of the ionic liquids are used to represent structural information. The study explores the impact of both ILs' chemical structure and process parameters on the efficiency of lignin recovery from different bio sources. The findings give an insight into the extraction process and could serve as a foundation for further design of efficient and selective processes for lignin recovery using ionic liquids, which can have significant implications for producing biofuels, chemicals, and materials.
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Modeling of free vibrations and resonant frequencies of simply-supported submerged horizontal plate
- Justyna Slawinska-Budzich
- Wojciech Sulisz
- Jarosław Przewłócki
A theoretical approach was applied to study the vibration of simple-supported submerged horizontal plate. The derived analytical solution was used to determine natural frequencies for a horizontal plate vibrating in fluid. The investigations were conducted for a very wide range of material density and elasticity modulus covering all materials used in engineering practice. Analysis shows that plate vibration frequency decreases with increasing plate width and draft, and decreases with decreasing plate thickness. Moreover, the results show that a substantial effect on vibration of submerged plate has mass of water above plate. The results also show that plate vibration frequency decreases with increasing plate material density and decreases with decreasing elasticity modulus. The dominant factors affecting the vibration of the submerged plate are the plate width, the plate thickness, and elasticity modulus. For moderate and low values of elasticity modulus, vibration frequency is becoming lower than frequency of water waves. This is very important because wave frequencies overlap with the natural plate vibration frequencies, which may lead to resonance and failure of a structure. The problem is that the overlap of plate vibration frequencies and wave frequencies occurs for very wide range of wave and plate parameters. Laboratory experiments confirm theoretical results.
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Modelling and Control of a Brushless Multiphase Doubly-Fed Induction Generator in a Stand-Alone Wind Generation System
- Krzysztof Blecharz
- Roland Ryndzionek
- Filip Kutt
The development of the novel multiphase brushless doubly-fed generator system and voltage controller for stand-alone mode configuration is proposed in this paper. The generator system is based on the new machine construction with multiphase control winding and traditional three-phase power winding. The dynamic model of multiphase brushless doubly-fed generator is presented, and the control strategy for voltage amplitude and frequency is developed. The simulation and experimental results are used to validate the performance of the topology of the multi-phase brushless double-fed generator and of the control system. The tests of the generator system have been carried out for the normal operating state of the system and for the case where one of the control phase is inactive. This situation is equivalent to a failure in the power path of the control winding.
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Modelling and simulations in time-fractional electrodynamics based on control engineering methods
- Damian Trofimowicz
- Tomasz Stefański
- Jacek Gulgowski
- Tomasz Talaśka
In this paper, control engineering methods are presented with regard to modelling and simulations of signal propagation in time-fractional (TF) electrodynamics. That is, signal propagation is simulated in electromagnetic media described by Maxwell’s equations with fractional-order constitutive relations in the time domain. We demonstrate that such equations in TF electrodynamics can be considered as a continuous-time system of state-space equations in control engineering. In particular, we derive continuous-time analytical solutions based on state-transition matrices for electromagnetic-wave propagation in the TF media. Then, discrete-time zero-order-hold equivalent models are developed and their analytical solutions are derived. It is demonstrated that the proposed models give the same results as other reference methods presented in the literature. However, due to the application of finite-difference scheme, they remain more flexible in terms of the number of simulation scenarios which can be tackled.
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Modelling tunnelling-induced deformation in stiff soils with a hyperelastic–plastic anisotropic model
- Marcin Cudny
- Katarzyna Lisewska
- Manuel Winkler
- Thomas Marcher
In this paper, the tunnelling-induced deformation in anisotropic stiff soils is analysed using FE modelling. The influence of material description is investigated rather than an advanced simulation of the tunnelling method. A new hyperelastic– plastic model is proposed to describe the anisotropic mechanical behaviour of stiff highly overconsolidated soil. This model can reproduce the superposition of variable stress-induced anisotropy and constant inherent cross-anisotropy of the small strain stiffness. Additionally, a Brick-type framework accounts for the strain degradation of stiffness. Formulation of the novel model is presented. The tunnelling-induced deformation is first investigated in plane strain conditions for a simple boundary value problem of homogeneous ground. The influence of initial stress anisotropy and inherent cross- anisotropy is inspected. Later, the results of 2D simulations are compared with the analogous results of 3D simulations considering different excavated length of the tunnel sections. The tunnelling process is reproduced by introduction of a supported excavation and a lining contraction stage in undrained conditions. Finally, the tunnelling case study at St James Park is back analysed using the proposed material model in plane strain conditions. The obtained calculation results are compared with the field measurements and discussed.
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Modelowanie dokładności radiolokalizowania w różnych warunkach środowiskowych przy wykorzystaniu interfejsu radiowego 5G-NR
- Piotr Rajchowski
- Luis M. Correia
- Krzysztof Cwalina
W artykule przedstawiono wyniki eksperymentalnych badań dokładności estymacji położenia terminala użytkownika korzystającego~z interfejsu radiowego 5G-NR. W środowisku miejskim dokonano rejestracji rzeczywistych sygnałów sieci 5G, a następnie przeprowadzono badania numeryczne. Celem było zweryfikowanie różnic dokładności estymacji położenia w trzech różnych środowiskach: wewnątrz- i zewnątrzbudynkowym oraz tzw. deep-indoor.
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Modern control strategy of bidirectional DAB converter with consideration of control nonlinearity
- Serafin Bachman
- Marek Turzyński
- Marek Jasiński
This paper focuses on the control strategy for modern universal bidirectional Dual Active Bridge (DAB) converters for microgrid systems. An analysis of the converter equations was carried out, and typical problems related to the influence of dead time on the system operation were discussed. A closed control loop was developed, then tested by simulation and on a laboratory stand.
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Modification of gradient HPLC method for determination of small molecules' affinity to human serum albumin under column safety conditions: Robustness and chemometrics study
- Mateusz Woziński
- Katarzyna Greber
- Monika Pastewska
- Piotr Kolasiński
- Weronika Hewelt-Belka
- Beata Żołnowska
- Jarosław Sławiński
- Daniel Szulczyk
- Wiesław Sawicki
- Krzesimir Ciura
In the early stages of drug discovery, beyond the biological activity screening, determining the physicochemical properties that affect the distribution of molecules in the human body is an essential step. Plasma protein binding (PPB) is one of the most important investigated endpoints. Nevertheless, the methodology for measuring %PPB is significantly less popular and standardized than other physicochemical properties, like lipophilicity. Here, we proposed how to modify protocols presented by Valko into column safety conditions and evaluated their robustness using fractional factorial design. For robustness testing, four factors were selected: column temperature, mobile phase flow rate, maximum isopropanol concentration in the mobile phase, and buffer pH. Elaborate methods have been applied for the analysis of HSA affinity for three groups of antibiotic-oriented substances that vary in chemical structure: fluoroquinolones, sulfonamides, and tetrazole derivatives. Furthermore, based on the reversed-phase chromatography the workflow of pilot studies was proposed to select molecules that have high affinity to HSA and can not be eluted from the HSA column using the concentration of organic modifier recommended by the column manufacturer
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Modified sliding mode control for seamless integration of P.V. energy in A.C. grid
- Shoaib Shaikh
- Arsalan Muhammad Soomar
- Kifayat Ullah
- Emad A.A. Ismail
- Fuad A. Awwad
- Muhammad Kamran
- Piotr Musznicki
- Syed Hadi Hussain Shah
Solar energy is a potentially abundant and reliable source of renewable energy. While it can undoubtedly increase grid reliability and efficiency, the inverted voltage generated from PV. sources may introduce distortion into the AC. grid. The proposed control mechanism, modified sliding mode control (MSMC), can seamlessly integrate the inverter output generated by obtaining DC. voltage from the boost converter linked with the PV. output. This research confirms the validity of the proposed method by comparing its results with a similar system that is only integrated through filters and with a system with a P.I. control technique. The simulation proves the effectiveness of seamlessly integrating the Photovoltaic (PV) source into the AC. grid.
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Molecular Design Using Selected Concentration Effects in Optically Activated Fluorescent Matrices
- Aneta Lewkowicz
- Katarzyna Walczewska-Szewc
- Martyna Czarnomska
- Emilia Gruszczyńska
- Mattia Pierpaoli
- Robert Bogdanowicz
- Zygmunt Gryczynski
Molecular physics plays a pivotal role in various fields, including medicine, pharmaceuticals, and broader industrial applications. This study aims to enhance the methods for producing specific optically active materials with distinct spectroscopic properties at the molecular level, which are crucial for these sectors, while prioritizing human safety in both production and application. Forensic science, a significant socio-economic field, often employs hazardous substances in analyzing friction ridges on porous surfaces, posing safety concerns. In response, we formulated novel, non-toxic procedures for examining paper evidence, particularly thermal papers. Our laboratory model utilizes a polyvinyl alcohol polymer as a rigid matrix to emulate the thermal paper’s environment, enabling precise control over the spectroscopic characteristics of 1,8-diazafluoro-9-one (DFO). We identified and analyzed the cyclodimer 1,8-diazafluoren-9-one (DAK DFO), which is a non-toxic and biocompatible alternative for revealing forensic marks. The reagents used to preserve fingerprints were optimized for their effectiveness and stability. Using stationary absorption and emission spectroscopy, along with time-resolved emission studies, we verified the spectroscopic attributes of the new structures under deliberate aggregation conditions. Raman spectroscopy and quantum mechanical computations substantiated the cyclodimer’s configuration. The investigation provides robust scientific endorsement for the novel compound and its structural diversity, influenced by the solvatochromic sensitivity of the DFO precursor. Our approach to monitoring aggregation processes signifies a substantial shift in synthetic research paradigms, leveraging simple chemistry to yield an innovative contribution to forensic science methodologies.
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Molecular transformation of dissolved organic matter in manganese ore-mediated constructed wetlands for fresh leachate treatment
- Md. Hasibur Rahaman
- Tong Yang
- Zhongyi Zhang
- Wenbo Liu
- Zhongbing Chen
- Jacek Mąkinia
- Jun Zhai
The organic matter (OM) and nitrogen in Fresh leachate (FL) from waste compression sites pose environmental and health risks. Even though the constructed wetland (CW) can efficiently remove these pollutants, the molecular-level transformations of dissolved OM (DOM) in FL remain uncertain. This study reports the molecular dynamics of DOM and nitrogen removal during FL treatment in CWs. Two lab-scale vertical-flow CW systems were employed: one using only sand as substrates (act as a control, CW-C) and the other employing an equal mixture of manganese ore powder and sand (experimental, CW-M). Over 488 days of operation, CW-M exhibited significantly higher removal rates for chemical oxygen demand (COD), ammonia nitrogen (NH4 +-N), and dissolved organic matter (represented by dissolved organic carbon, DOC) at 98.2 ± 2.5%, 99.2 ± 1.4%, and 97.9 ± 1.9%, respectively, in contrast to CW-C (92.8 ± 6.8%, 77.1 ± 28.1%, and 74.7 ± 9.5%). The three-dimensional fluorescence excitation-emission matrix (3D-EEM) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analyses unveiled that the influent DOM was predominantly composed of readily biodegradable protein-like substances with high carbon content and low unsaturation. Throughout treatment, it led to the degradation of low O/C and high H/C compounds, resulting in the formation of DOM with higher unsaturation and aromaticity, resembling humic-like substances. CW-M showcased a distinct DOM composition, characterized by lower carbon content yet higher unsaturation and aromaticity than CW-C. The study also identified the presence of Gammaproteobacteria, reported as Mn-oxidizing bacteria with significantly higher abundance in the upper and middle layers of CW-M, facilitating manganese cycling and improving DOM removal. Key pathways contributing to DOM removal encompassed adsorption, catalytic oxidation by manganese oxides, and microbial degradation. This study offers novel insights into DOM transformation and removal from FL during CW treatment, which will facilitate better design and enhanced performance.
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Molecularly imprinted polymers based on deep eutectic solvents as a greenest materials for selective extraction of emerging contaminants from complex samples
- Mariusz Marć
- Natalia Jatkowska
- Justyna Płotka-Wasylka
- Daniel Gallart-Mateu
- Francesc A. Esteve‐turrillas
- Miguel De la Guardia
Some of the reagents applied in the synthesis of molecularly imprinted polymers (MIPs) may impact on health and the environment. Thus, a new generation of promising green chemicals are nowadays introduced and investigated, including deep eutectic solvents (DESs). DESs seems to be a reasonable choice as they are characterized as non-toxic, low cost, easy to prepare and biodegradable chemicals. This review presents the information on imprinted materials prepared using versus polymerization techniques on which DESs were applied as a more green reagents. Paper presents the benefits and roles of DESs application in the synthesis of MIPs and their potential application area such as selective and reversible sorbents/resins in analytes extraction process as well as chromatographic stationary phases. Furthermore, the specific fields of application of new type of DES-based MIPs in environmental, food and biological samples analysis are described and the future remarks in the area of DES-based MIPs are discussed.
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Molecularly imprinted polymers for the detection of volatile biomarkers
- Tomasz Wasilewski
- Sinem Orbay
- Nathália F. Brito
- Karol Sikora
- Ana Claudia A. Melo
- Matias E. Melendez
- Bartosz Szulczyński
- Amitav Sanyal
- Wojciech Kamysz
- Jacek Gębicki
In the field of cancer detection, the development of affordable, quick, and user-friendly sensors capable of detecting various cancer biomarkers, including those for lung cancer (LC), holds utmost significance. Sensors are expected to play a crucial role in the early-stage diagnosis of various diseases. Among the range of options, sensors emerge as particularly appealing for the diagnosis of various diseases, owing to their cost-effectiveness, simplicity, and promising analytical performance. There is growing interest in the application of molecularly imprinted polymers (MIPs) as promising recognition elements in gas sensors. MIPs, as a leading technology for sensing analytes where no suitable bioreceptor exists, are commonly used in artificial sensing that can be applied in key fields like early disease diagnostics, based on the detection of volatile biomarkers. There is an extensive demand for early, non-invasive detection of various diseases and for the self-monitoring of health conditions. Detection of biomarkers in point-of-care mode remains challenging and is limited by various factors. Hence, breath analysis has received enormous attention in healthcare due to its relatively low cost, non-invasive sampling method, and rapid detection capabilities. The latest developments in MIP-based sensors and their utility in disease diagnosis through the detection of volatile biomarkers are comprehensively and critically evaluated in this review. Furthermore, the challenges and perspectives of MIP-based sensors are elaborated upon, with a view towards introduction to the market and successful commercialization.
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Monte-Carlo Modeling of Optical Sensors for Postoperative Free Flap Monitoring
- Paulina Stadnik
- Ignacy Rogoń
- Mariusz Kaczmarek
This work aims to develop a numerical tissue model and implement software to simulate photon propagation using the Monte Carlo method to determine design guidelines for a physical measurement system. C++ was used for the simulation program, and Python as a programming environment to create an interface that allows the user to customize individual simulation elements, allowing for increased accuracy and flexibility when simulating photon movement. This allows the user to customize the simulation to their specific requirements, ensuring the results are as accurate and reliable as possible. It also models the detector to determine if a given photon is in the desired location. The program simulates the propagation of light from a normal illumination medium with anisotropic scattering and records the escape of photons on the upper surface. The simulation also takes into account absorption and scattering coefficients for a given wavelength, and data regarding these parameters are read from a .csv file. The variance reduction technique is used to improve the efficiency of the simulation. The user interface allows users to define their own parameters, such as wavelength, anisotropy coefficient, refractive index, and layer thickness. In this paper, we simulate four photodiodes and different distances between the source and detector to determine the most suitable model for designing a physical sensor.
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More than just a beer – Brewers' spent grain, spent hops, and spent yeast as potential functional fillers for polymer composites
- Aleksander Hejna
- Mateusz Barczewski
- Paulina Kosmela
- Joanna Aniśko
- Joanna Szulc
- Katarzyna Skórczewska
- Adam Piasecki
- Tairong Kuang
Beer is among the most popular beverages in the world, with the production distributed uniformly between the biggest continents, so the utilization of brewing by-products is essential on a global scale. Among their potential recipients, the plastics industry offers extensive range of potential products. Herein, the presented study investigated the application of currently underutilized solid brewing by-products (brewers' spent grain, spent hops, spent yeast) as fillers for highly-filled poly(ε-caprolactone)-based composites, providing the first direct connection between spent hops or spent yeast and the polymer composites. Comprehensive by-product characterization revealed differences in chemical composition. The elemental C:O ratio, protein content, and Trolox equivalent antioxidant capacity varied from 1.40 to 1.89, 12.9 to 32.4 wt%, and 2.41 to 10.24 mg/g, respectively, which was mirrored in the composites' structure and performance. Morphological analysis pointed to the composition-driven hydrophilicity gap limiting interfacial adhesion for high shares of brewers' spent grain and spent hops, due to high hydrophilicity induced by carbohydrate content. Phytochemicals and other components of applied by-products stimulated composites' oxidative resistance, shifting oxidation onset temperature from 261 °C for matrix over 360 °C for high spent yeast shares. Simultaneously, spent yeast also provided compatibilizing effects for poly(ε-caprolactone)-based composites, reducing complex viscosity compared to other fillers and indicating its highest affinity to poly(ε-caprolactone)due to the lowest hydrophilicity gap. The presented results indicate that the proper selection of brewing by-products and adjustment of their shares creates an exciting possibility of engineering composites' structure and performance, which can be transferred to other polymers differing with hydrophilicity.
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Morphology and internal structure of small-scale washovers formed in the coastal zone of the semi-enclosed tideless basin, Gulf of Gdańsk, Baltic Sea
- D. Moskalewicz
- F. Bahr
- Łukasz Janowski
- K. Leszczyńska
- P. Sitkiewicz
- M. Słowik
- K. Stattegger
- Paweł Tysiąc
- C. Winter
This study explores the morphological features and internal structure of small-scale washovers along the southeastern Baltic Sea coast, providing insights into these most widespread yet often neglected deposits in the recent research of geomorphological and sedimentary record of storm surges. A 15-year-long record of morphological changes of the coast was acquired from regional orthophotos to analyse their geometry and spatial characteristics. Sedimentological analyses comprising a description of deposits, grain size and shape analyses, and Ground Penetrating Radar profiling were undertaken to investigate the internal structure of washovers. The formation of washovers appeared to be correlated with the average winter NAO (North Atlantic Oscillation) index. The study revealed different scaling relationships of selected spatial parameters in two coastal settings and extended previously hypothesized relationships of length-area, area-volume, and length-volume. The internal structure of washovers is defined by low-angle planar cross-stratification and horizontal stratification, both disrupted by small troughs. Grain-size data indicated extremely short transport of dune and beach sediments, lately deposited in the form of washovers. The study proves that in all domains, the geomorphological characteristics of washovers are scalable, despite the different coastal settings, and even small-scale washovers fit the existing development models
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Most średnicowy w Warszawie. Koncepcja przebudowy
- Krzysztof Żółtowski
- Mikołaj Binczyk
- Przemysław Kalitowski
- Piotr Żółtowski
- Sebastian Chylewski
- Daniel Pełka
- Tomasz Jabłoński
Artykuł omawia koncepcję przebudowy Mostu Średnicowego w Warszawie, który, ze względu na zły stan techniczny i nieprzystosowanie do współczesnych wymagań, wymaga rekonstrukcji. Planowana przebudowa obejmuje wykorzystanie istniejących filarów nurtowych oraz wydłużenie mostu, co pozwoli na eliminację wiaduktów nad Wisłostradą i Wybrzeżem Szczecińskim. Przedstawiono trzy warianty konstrukcyjne: kratownicę o zmiennej wysokości, skrzynkowe przęsła blachownicowe oraz konstrukcję nawiązującą do pierwotnego projektu z lat 20. XX wieku. Analizy nośności i detali konstrukcyjnych wykonano przy użyciu zaawansowanych modeli numerycznych w środowisku MES SOFiSTiK. Ostatecznie inwestor wybrał do dalszego projektowania wariant łukowy. Prace projektowe były częścią większej modernizacji całej Linii Średnicowej w Warszawie, której realizacja ma kluczowe znaczenie dla funkcjonowania stołecznego węzła kolejowego.
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MSP for port areas – To what extent should we interfere with governance of ports’ waters? Case study of Polish seaports
- Ernest Czermański
- Magdalena Matczak
- Aneta Oniszczuk-Jastrząbek
- Karolina Krośnicka
- Joanna Witkowska
The EU MSP Directive imposed the requirement to develop plans for all water areas under the jurisdiction of an EU country by the end of March 2021. Poland is the only country in the Baltic Sea Region whose maritime administration has decided to elaborate detailed maritime spatial plans for port waters. The aim of the paper is to draw conclusions from the work carried out so far on the MSP for Polish port water areas. For this purpose, the drafts of the first ever plans for port areas, constituting Poland’s internal marine waters, were considered. The authors analysed planning efforts concerning Polish port water areas in two stages, quantitative and qualitative. The subjects of the analysis were the draft spatial maritime plans, prepared or in preparation, for three selected ports – Gdańsk, Szczecin and Elbląg. These study cases were chosen to represent the best variety of approaches (they were elaborated by different planning companies, having very different planning backgrounds) and were the basis for evaluating the solutions proposed in the draft plans in terms of possible interpretations of the plan’s provisions. The paper raises such questions as: What kind of functions (uses) occur while elaborating the maritime spatial plan of the port’s waters?; How are the functions distinguished within the ports’ plans interpreted by planers originating from different environments and having different types of planning experience?; How could the process of maritime spatial planning for port waters be coordinated between port authorities, maritime administration, and municipal authorities?
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Multi-Analytical Techniques for the Study of Burial Clothes of Polish King Sigismund III Vasa (1566–1633) and His Wife Constance Habsburg (1588–1631)
- Magdalena Śliwka-Kaszyńska
- Maria Cybulska
- Anna Drążkowska
- Sławomir Kuberski
- Jakub Karczewski
- Anna Marzec
- Przemysław Rybiński
The subjects of this research are the burial clothes of Polish King Sigismund III Vasa and his wife Constance, which were woven and embroidered with silk and metal threads. Fragments of the textiles underwent spectroscopic, spectrometric, and thermogravimetric analyses. The hydrofluoric acid extraction method was improved to isolate various classes of dyes from the textile samples that had direct contact with human remains. High-performance liquid chromatography, coupled with diode array and tandem mass spectrometry detectors with electrospray ionization (HPLC-DAD-ESIMS/ MS) facilitated the detection and identification of colorants present in the textiles. Cochineal, indigo-, madder-, orchil-, and tannin-producing plants were identified as the sources of dyes used. Scanning electron microscopy with an energy-dispersive X-ray detector (SEM-EDS) was employed to identify and characterize the silk fibers and mordants and the metal threads. The presence of iron, aluminum, sodium, and calcium in the silk threads suggests their potential use as mordants. The analysis of the metal threads revealed that most of them were made from flattened gilded silver wire, with only a few being cut from a sheet of metal. Typical degradation mechanisms of metal threads were shown, resulting from both burial environment and earlier manufacturing process, and the use of the textiles in clothing, i.e., a significant loss of the gold layer was observed in most of silver gilt threads, caused by abrasion and delamination. The results of the thermal analysis confirmed the presence of silk and silver threads in the examined textiles.
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Multi-channel radio-over-fiber communication systems through modulation instability phenomenon
- Rasul Azizpour
- Hassan Zakeri
- Gholamreza Moradi
- Mohammad Alibakhshikenari
- Francisco Falcone
- Liu Bo
- Tayeb Dendini
- Imko Park
- Sławomir Kozieł
- Ernesto Limiti
Recent advancements in Radio-over-Fiber (RoF) technology have positioned it as a promising solution for highcapacity wireless communications. This paper explores novel applications of RoF systems in enhancing phased array antenna (PAA) performance for multi-channel wireless communication applications through the modulation instability (MI) phenomenon. Utilizing fibers experiencing MI with varying group velocity dispersions (β2) of -20, -11.3, -3.2, and -2 ps2/km, the RoF system achieves operational flexibility across distinct central frequencies of 12, 16, 30, and 38 GHz, respectively. This approach represents a significant advancement in wireless communication technology, leveraging MI gain and an MI-based control system architecture to enhance performance across diverse frequency bands. The study investigates the impact of MI on modulation efficiency, presenting experimental results validating the feasibility and effectiveness of the proposed approach. The maximum MI gain by employing a 30 km fiber under MI is 18 dB, experimentally. Further optimization, achieved by increasing the fiber length to 45 km and adjusting nonlinear parameters and input power, demonstrates a remarkable MI gain of 38.1 dB. MIbased true time delay (TTD) techniques also address beam squint challenges, enhancing beamforming capabilities. The findings suggest that integrating MI into RoF systems holds excellent potential for improving wireless communication capabilities with reduced costs and space requirements compared to conventional methods. This research contributes to the growing body of knowledge in the field of RoF systems and offers insights into their practical applications in modern wireless communication networks.
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Multi-factor fuzzy sets decision system forecasting consumer insolvency risk
- Tomasz Korol
The objective of this study is to develop a multi-factor decision system predicting insolvency risk for natural persons with the use of fuzzy sets. Considering that the financial situation of households is affected by various endogenous and exogenous factors, the main assumption of this study is that the system for predicting financial difficulties should not be limited to the use of only a few financial variables concerning consumers, but also include variables describing the environment. The author proposes a system consisting of three different forecasting models that connect the macroeconomic and microeconomic environments. It monitors the economic situation of households by also identifying those environmental variables, which may directly, or indirectly, endanger the consumer, such as unemployment rate (job market situation), inflation and interest rates, exchange rates, or economic situation in the country (GDP growth rate, the dynamics of retail sales, etc.). Moreover, the created multi-factor tool is in the form of a flexible application that can be easily adapted to changing economic conditions. Another unique feature of the study is the proposed use of newly developed ratios in household finance, similar to that in financial ratio analysis, which is commonly used in corporate finance. The proposed ratios demonstrated high predictive abilities. The paper also identifies the predictive capabilities of selected macroeconomic variables from the perspective of their impact on the risk of consumer insolvency. The research relies on four samples consisting of a total of 2,400 consumers from Taiwan and Poland. The author created three forecasting models separately for the South-East Asian and Central European regions, and two multi-factor systems, each consisting of 1260 decision rules. The findings clearly showed that a multi-factor system is a significantly more effective method compared to single forecasting models.
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Multi-instrument analysis of L-band amplitude scintillation observed over the Eastern Arabian Peninsula
- Abdollah Masoud Darya
- Muhammad Mubasshir Shaikh
- Grzegorz Nykiel
- Essam Ghamry
- Ilias Fernini
The study of scintillation-causing ionospheric irregularities is important to mitigate their effects on satellite communications. It is also important due to the spatial and temporal variability of these irregularities, given that their characteristics differ from one region to another. This study investigates the spatial and temporal characteristics of L1 amplitude scintillation-causing ionospheric irregularities over the Eastern Arabian Peninsula during the ascending phase of solar cycle 25 (years 2020–2023). The temporal occurrences of weak and strong scintillation were separated by sunset, with weak scintillation observed predominantly pre-sunset during the winter solstice and strong scintillation observed mainly post-sunset during the autumnal equinox. Strong scintillation was much more pronounced in 2023 compared to the other three years, indicating a strong influence of solar activity. Spatially, weak-scintillation-causing irregularities exhibited a wide distribution in azimuth and elevation, while strong-scintillation-causing irregularities were concentrated southwards. The combined analysis of S4 and rate of total electron content index (ROTI) suggested that small-scale ionospheric irregularities were present in both pre- and post-sunset periods, while large-scale irregularities were only seen during the post-sunset period. Furthermore, the presence of southward traveling ionospheric disturbances (TIDs) during the 2023 autumnal equinox was confirmed with the total electron content anomaly (dTEC), while the Ionospheric Bubble Index (IBI) provided by the Swarm mission was unable to confirm the presence of equatorial plasma bubbles during the same period. Observations from the FORMOSAT-7/COSMIC-2 mission indicated that strong-scintillation-causing irregularities were more prevalent under the F2-layer peak, while the weak-scintillation-causing irregularities were mostly observed at the E-layer, F2-layer, and above the F2-layer. This study aims to contribute insights into the behavior of scintillation-causing ionospheric irregularities in the region, with implications for future research during the peak of the 25th solar cycle.
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Multilayer coatings based on cerium oxide and manganese cobaltite spinel for Crofer22APU SOC interconnects
- Elisa Zanchi
- Justyna Ignaczak
- Grzegorz Cempura
- Sebastian Molin
- Aldo R. Boccaccini
- Federico Smeacetto
The current state of the art steel interconnect coating materials are based on critical raw material - Co-oxide spinels. Replacing Co-oxide spinels with alternative, abundant materials can reduce the dependence on the critical raw materials. Cobalt-free coatings with the general formula Mn2-xCuFexO4, where x = 0, 0.1, 0.3, were electrophoretically deposited on a ferritic stainless-steel support and evaluated. Prior to deposition, the powders were prepared by a soft chemistry process and studied in terms of crystallographic phase analysis, electrical conductivity, thermal expansion, and sinterability behaviour. Coated steel samples were oxidised in an air atmosphere at 750 °C for 3000 h. In parallel, a state-of-the-art MnCo2O4 spinel oxide was tested as a reference. The coatings and oxide scale microstructures of the surfaces and cross-sections were examined by XRD, and SEM-EDX. TEM-EDX, XRF, and micro-XRD were also performed on the cross-section lamellae. The electrical properties of the steel-coating system were evaluated by Area Specific Resistance measurement. The results confirm that Mn–Cu–Fe oxides exhibit higher conductivity and lower TEC than Mn–Co oxide. Based on the obtained results, it might be concluded that the proposed coatings are a promising alternative to coatings that contain cobalt.
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Multimodal analysis of traction forces and the temperature dynamics of living cells with a diamond-embedded substrate
- Tomasz Kołodziej
- Mariusz Mrózek
- Saravanan Sengottuvel
- Maciej Głowacki
- Mateusz Ficek
- Wojciech Gawlik
- Zenon Rajfur
- Adam M. Wojciechowski
Cells and tissues are constantly exposed to chemical and physical signals that regulate physiological and pathological processes. This study explores the integration of two biophysical methods: traction force microscopy (TFM) and optically detected magnetic resonance (ODMR) to concurrently assess cellular traction forces and the local relative temperature. We present a novel elastic substrate with embedded nitrogen-vacancy microdiamonds that facilitate ODMR-TFM measurements. Optimization efforts focused on minimizing sample illumination and experiment duration to mitigate biological perturbations. Our hybrid ODMR-TFM technique yields TFM maps and achieves approximately 1 K precision in relative temperature measurements. Our setup employs a simple wide-field fluorescence microscope with standard components, demonstrating the feasibility of the proposed technique in life science laboratories. By elucidating the physical aspects of cellular behavior beyond the existing methods, this approach opens avenues for a deeper understanding of cellular processes and may inspire the development of diverse biomedical applications.
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Multiscalar Control Based Airgap Flux Optimization of Induction Motor for Loss Minimization
- Tadele Ayana
- Marcin Morawiec
- Lelisa Wogi
Based on the induction motor model, considering the core loss resistance that accounts for magnetic characteristic saturation, a speed control approach is devised with an adaptive full-order (AFO) speed observer. The induction motor model analysis is done sincerely in a stationary reference frame. The control approach incorporates a flux reference generator designed to meet optimal operational circumstances and a nonlinear speed controller. The machine state variables are involved in flux generation and speed control rules. The performance of the proposed control strategy is formally studied by simulation and demonstrated through experiments. The technique exhibits fast convergence to the optimal flux level, reduces computational resource requirements, and enhances torque production and loss minimization accuracy. It eliminates the excessive flux demands compared to open-loop steady-state values, which will necessitate greater current levels without justification, resulting in an increased power dissipated. This optimum flux level minimizes induction motor losses for efficiency increments.
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Multi-Taper-Based Automatic Correction of Non-Anechoic Antenna Measurements
- Mariusz Dzwonkowski
- Vorya Waladi
- Adrian Bekasiewicz
Prototype measurements belong to the key steps in the development of antenna structures. Although accurate validation of their far-field performance can be realized in dedicated facilities, such as anechoic chambers, the high cost of their construction and maintenance might not be justified if the main goal of measurements is to support teaching or low-budget research. Instead, they can be performed in non-anechoic conditions and then refined using appropriate correction algorithms. Unfortunately, the existing post-processing methods suffer from multiple challenges that include manual setup of parameters as well as validation of performance in idealized conditions. In this communication, a multi-taper-based framework for correction of antenna characteristics obtained in non-anechoic environments has been proposed. The algorithm augments one-shot measurements of the structure under test in order to extract the line-of-sight responses while attenuating the interferences pertinent to multi-path propagation and noise from external sources of radiation. The performance of the proposed correction routine has been demonstrated in two test sites using a geometrically small Vivaldi radiator and validated against state-of-the-art techniques from the literature. The uncertainty budget for the measurements performed using the approach amounts to 0.26 dB, which is low given challenging propagation conditions considered for experiments.
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Multitaper-Based Post-processing of Compact Antenna Responses Obtained in Non-anechoic Conditions
- Mariusz Dzwonkowski
- Adrian Bekasiewicz
- Sławomir Kozieł
The process of developing antenna structures typically involves prototype measurements. While accurate validation of far-field performance can be performed in dedicated facilities like anechoic chambers, high cost of construction and maintenance might not justify their use for teaching, or low-budget research scenarios. Non-anechoic experiments provide a cost-effective alternative, however the performance metrics obtained in such conditions require appropriate correction. In this paper, we consider a multitaper approach for post-processing antenna far-field characteristics measured in challenging, non-anechoic environments. The discussed algorithm enhances one-shot measurements to enable extraction of line-of-sight responses while attenuating interferences from multi-path propagation and the noise from external sources of electromagnetic radiation. The performance of the considered method has been demonstrated in uncontrolled conditions using a compact spline-based monopole. Furthermore, the approach has been favorably validated against the state-of-the-art techniques from the literature.
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MXene-based composites for capacitive deionization – The advantages, progress, and their role in desalination - A review
- Bakhtiar Ali Samejo
- Kainat Naseer
- Suraya Samejo
- Farooque Janjhi
- Najma Memon
- Roberto Castro Munoz
- Grzegorz Boczkaj
MXenes, a novel large family of 2D transition metal carbides, carbonitrides and nitrides are currently a “hot topic” in science due to their several fascinating physical and chemical properties. It follows from a rich diversity of their elemental compositions and chemical functionalities. MXenes can form composites with many substances, including polymers or metal oxides, which allows to effective “tune” MXene characteristics to a fit-to-the-purpose applications. Capacitive deionization (CDI) is currently widely studied as advanced desalination technique due to the advantages of cost-effectiveness, eco-friendly, and high salt removal capacity. One of key fields for CDI development relates to the ion's intercalation materials as concept taken from the sodium ion batteries, which is used in CDI because of their excellent desalination capacity. These materials provide effective sodium ions removal from the brine based on intercalation mechanism as well as redox reactions. In this review, we timely review an up-to-date accomplishment in the advancement of distinct MXene-based composite materials used as CDI electrodes, along with discussion of fundamental electrochemical energy storage mechanisms. The most relevant outcomes are highlighted together with the phenomena observed when applied in desalination applications. Finally, potential solutions as well as challenges in this field are summarized.
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Nadmiarowe zgony podczas pandemii COVID-19 w Polsce i ocena skuteczności szczepień
- Błażej Kochański
- Jakub Sochacki
Z powodu pandemii COVID-19 zmarły miliony ludzi na całym świecie. Jak wynika z wielu badań, szczepienia przeciw chorobie wywołanej wirusem SARS-CoV-2 okazały się środ-kiem ograniczającym skalę zachorowań i liczbę zgonów. Celem badania omawianego w artyku-le jest pomiar skali pandemii w Polsce za pomocą liczby nadmiarowych zgonów w podregio-nach według klasyfikacji NUTS 3 i w grupach wieku, a następnie określenie zależności pomiędzy zróżnicowaniem regionalnym względnej nadwyżki zgonów podczas czwartej fali pandemii a stopniem zaszczepienia populacji. Nadmiarowe zgony są rozumiane jako nadwyżka zgonów zarejestrowanych w stosunku do przewidywanego poziomu. Badaniem objęto okres od marca 2020 r. do lutego 2022 r. Korzystano z zasobów Eurostatu i Głównego Urzędu Statystycznego oraz danych pobranych z rządowego portalu Otwarte Dane. Analiza liczby nadmiarowych zgonów w podziale na grupy wieku wskazuje, że niemal 90% to zgony osób starszych (w wieku 60 lat i więcej). Z kolei pomiar w podziale na podregiony pozwala stwierdzić, że korelacja nadmiarowych zgonów i udziału zaszczepionych jest ujemna i dość silna. Przy założeniu występowania prostej regresji liniowej okazuje się, że dodatkowy 1% osób zaszczepionych w starszych grupach wieku przełożyłby się średnio na spadek liczby zgonów podczas czwartej fali pandemii o blisko 2000 w skali kraju. Ten wynik świadczy o tym, że szczepienia przeciw COVID-19 były skuteczne w zapobieganiu zgonom z powodu tej choro-by wśród osób starszych.
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Nadzór i monitorowanie dostępności ZIntegrowanych Węzłów Przesiadkowych
- Marcin Budzyński
- Tomasz Mackun
- Jacek Szmagliński
- Romanika Okraszewska
- Kazimierz Jamroz
- Lech Michalski
- Joanna Wachnicka
Audyt dostępności dla planowanych, projektowanych i istniejących węzłów przesiadkowych musi być przeprowadzony w kontekście społecznym i prawnym, w którym re- alizowany jest projekt. W Polsce prawa osób z niepełnosprawnościami reguluje m.in. ustawa z dnia 19 sierpnia 1997 r. o rehabilitacji zawodowej i społecznej oraz zatrudnianiu osób niepełnosprawnych oraz ustawa z dnia 27 sierpnia 1997 r. o rehabilitacji społecznej i zawodowej oraz zatrudnianiu osób niepełnosprawnych. Obie ustawy określają prawa osób z niepełnosprawnościami, m.in. w zakresie dostępności do budynków i urządzeń użyteczności publicznej. Ponadto w Polsce obowiązuje ustawa z dnia 19 lipca 2019 r. o zapewnieniu dostępności osobom ze szczególnymi potrzebami. Ustawa ta nakłada na podmioty publiczne i prywatne obowiązek zapewnienia dostępności swoich usług, w tym węzłów przesiadkowych, dla osób o szczególnych potrzebach. W kontekście społecznym należy zwrócić uwagę na fakt, że osoby z niepełnosprawnościami stanowią znaczącą część społeczeństwa. Z danych Głównego Urzędu Statystycznego wynika, że w Polsce mieszka około 4,5 mln osób z niepełnosprawnościami. Dlatego projektowanie węzłów przesiadkowych musi uwzględniać potrzeby tej grupy osób. Warto również zwrócić uwagę na fakt, że projektowanie węzłów przesiadkowych i ich przekształcanie z myślą o dostępności dla osób o szczególnych potrzebach może wpłynąć pozytywnie na poprawę jakości życia całego społeczeństwa. Dostępność do transportu publicznego dla osób z niepełnosprawnościami może przyczynić się do zwiększenia ich aktywności i integracji ze społeczeństwem. W kontekście społecznym i prawnym audyt dostępności dla węzłów przesiadkowych jest nie tylko konieczny, ale również pozytywnie wpłynie na poprawę jakości życia osób z niepełnosprawnościami oraz całego społeczeństwa.
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Nanofiltration-Assisted Concentration Processes of Phenolic Fractions and Carotenoids from Natural Food Matrices
- Roberto Castro Munoz
In new food formulations, carotenoids and phenolic compounds are likely to be the most sought after food ingredients according to their bioactivity, nutraceutical, nutritional value, and compatibility properties once incorporated into food formulations. Such solutes are naturally present in many plant-based sources, and some portions are directly consumed when enriching food products and formulations; however, some portions, which are contained in the parts of the plant sources not considered edible, including the leaves, peel, and seeds, among other by-products, are commonly wasted. Related to this, scientists have found a new window for obtaining these bioactive molecules, but their recovery remains a challenge. To some extent, the final purification and polishing requires highly selective performance to guarantee the desired properties and concentration. In this regard, membrane technologies, such as nanofiltration (NF), represent an alternative, owing to their highly selective properties when separating low-molecular-weight compounds. NF becomes immediately suitable when the pretreated extracts are subjected to further efficient concentration, fractionation, and polishing of phenolic fractions and carotenoids. The separation efficiency (usually higher than 97%) of NF technology is high according to the low pore size of NF membranes, but the low temperature in process separation also contributes to the separation of thermolabile compounds. Therefore, this paper reviews the ongoing cases of studies reporting the successful separation and polishing of phenolic fractions and carotenoids from distinct sources. In particular, we have focused our attention on the main interactions during the separation process and the drawbacks and advantages of using membranes for such a case study.
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Nanomateriały o właściwościach magnetycznych, fotokatalitycznych, biobójczych
- Izabela Malinowska
Tematyka badawcza pracy doktorskiej obejmuje preparatykę i charakterystykę nanomateriałów o właściwościach magnetycznych, fotokatalitycznych, biobójczych. Celem pracy była preparatyka nanomateriałów na bazie TiO2 oraz ZnFe2O4 oraz zastosowanie nanokompozytów w fotokatalizie heterogenicznej do degradacji ksenobiotyków niepodatnych na rozkład biologiczny i otrzymywania funkcjonalnych materiałów budowlanych. Otrzymane nanokompozyty scharakteryzowano za pomocą analizy powierzchni właściwej BET wraz z objętością porów, analizy rentgenograficznej XRD, analizy pętli histerezy magnetycznej oraz analizy mikroskopii elektronowej STEM. Otrzymane nanomateriały charakteryzują się właściwościami magnetycznymi, fotokatalitycznymi, biobójczymi. Taka hybrydowość właściwości pozwala na zastosowanie opisywanych materiałów jako fotokatalizatorów oraz dodatków do powszechnie znanych powłok ochronno-dekoracyjnych w celu nadania im nowych hybrydowych właściwości.
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Nanoparticle-assisted biohydrogen production from pretreated food industry wastewater sludge: Microbial community shifts in batch and continuous processes
- Mohamed Saad Hellal
- Filip Gamoń
- Grzegorz Cema
- Gamal K. Hassan
- Ginedy Mohamed Gehad
- Aleksandra Ziembińska-Buczyńska
Biohydrogen production from industrial waste has gained a significant attention as a sustainable energy source. In this study, the enrichment of biohydrogen production from pretreated dissolved air flotation (DAF) sludge, generated from food industry wastewater treatment plants, was investigated using SiO2@Cu-Ag dendrites cor- e–shell nanostructure (NS). The effect of NS on the changes of the microbial community and biohydrogen yield was evaluated through batch and continuous tests. In batch mode, various nanomaterial doses were investigated with several concentrations ranging from 20 to 50 mg/L for hydrogen production using glucose as a substrate. The optimum core–shell NS amount was 40 mg/L, achieving a maximum H2 yield of 163 mL/g volatile solids (VS) compared to the control’s 79 mL/g VS. However, 50 mg/L NS inhibited most bacteria in the sludge. The continuous experiment used a continuous stirring tank reactor (CSTR) with 40 mg/L SiO2@Cu-Ag core–shell NS and pretreated industrial sludge as substrate. The H2 yield increased to 115 L/kg VS compared to the control reactor’s 89 L/kg VS. The gas analysis showed compositional proportions of 83 % H2, 7 % CO2, and 4.5 % methane, while the microbial community analysis indicated the development of hydrogen-producing species such as Clostridium. In conclusion, SiO2@Cu-Ag core–shell NS addition enhanced anaerobic degradation of organic matter and its conversion to biohydrogen. The selected nanomaterial can be used for an effective continuous treatment system for industrial sludge while promoting dark fermentation.
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Napęd z silnikiem indukcyjnym i 4-gałęziowym falownikiem SiC do turbosprężarek powietrza ogniw paliwowych dużej mocy
- Marek Adamowicz
- Sebastian Giziewski
Wysoka cena ogniw paliwowych utrudnia ich szerokie zastosowanie w transporcie i przemyśle. Należy szukać możliwości obniżenia ich kosztu również poprzez obniżenie kosztu i zwiększenie wydajności urządzeń pomocniczych ogniwa paliwowego (Balance of the Plant). Autorzy proponują aby w napędzie sprężarki powietrza, zastosować wysokoobrotowy silnik indukcyjny, który jest tańszy od stosowanych obecnie silników PMSM. W referacie zaproponowano napęd z czterogałęziowym falownikiem SiC i wysokoobrotowym silnikiem indukcyjnym o mocy 6,3 kW, prędkości obrotowej 79 800 obr/min i częstotliwości zasilania 2667 Hz, który może być zastosowany do turbosprężarki powietrza ogniwa paliwowego o mocy 100 kW.