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Gdańsk University of Technology

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  • Low noise poroelastic road pavements based on modified asphalt binder
    • Jerzy Ejsmont
    • Beata Świeczko-Żurek
    • Władysław Gardziejczyk
    2020

    Tire/road noise is one of the most important environmental problems related to road traffic. As the most effective way to fight noise is reduction of sound emission from the source, a lot of work is being done to improve tire and road surfaces construction. This paper describes the first “road” results obtained within the SEPOR project, which is focused on developing a low noise poroelastic road surface based on bituminous binder. It is also a continuation of the paper presented during NOISE-CON 2019 conference that described the preliminary results of laboratory tests and small scale experiments. The paper presents results of measurements performed on two road sections paved with poroelastic material in 2019. The technologies used on these test sections were aimed at eliminating the problems that occurred with poroelastic surfaces using polyurethane binder and in particular increasing the durability of the surface (especially in terms of adhesion to the base layer) as well as reducing rolling resistance. The paper describes the results of tire noise, sound absorption, drainage properties and rolling resistance tests. Experience to date indicates that bituminous binder has eliminated the most troublesome problems of poroelastic road surfaces, but at this stage of development the achieved noise reduction is not as high as expected so more trials will be performed in 2020.

  • Low-Cost Automated Design of Compact Branch-Line Couplers
    • Adrian Bekasiewicz
    2020 Full text SENSORS

    Branch-line couplers (BLCs) are important components of wireless communication systems. Conventional BLCs are often characterized by large footprints which make miniaturization an important prerequisite for their application in modern devices. State-of-the-art approaches to design of compact BLCs are largely based on the use of high-permittivity substrates and multi-layer topologies. Alternative methods involve replacement of transmission-line sections of the circuit with their composite counterparts referred to as compact cells (CCs). Owing to efficient use of available space, CC-based couplers are often characterized by small footprints. Design of compact BLCs is normally conducted based on engineering experience. The process is laborious and requires many adjustments of topology followed by manual or, semi-automatic tuning of design parameters. In this work, a framework for low-cost automated design of compact BLCs using pre-defined CCs is proposed. Low cost of the presented design technique is ensured using equivalent-circuit models, space mapping correction methods, and trust-region-based local optimization algorithms. Performance of the framework is demonstrated using three examples concerning design of unequal-power split coupler, comparison of automatically generated compact BLCs, as well as rapid re-design of the coupler for different substrates. Furthermore, the approach has been benchmarked against the state-of-the-art methods for low-cost design of circuits.

  • Low-cost data-driven modelling of microwave components using domain confinement and PCA-based dimensionality reduction
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2020 IET Microwaves Antennas & Propagation

    Fast data-driven surrogate models can be employed as replacements of computationally demanding full-wave electromagnetic simulations to facilitate the microwave design procedures. Unfortunately, practical application of surrogate modelling is often hindered by the curse of dimensionality and/or considerable nonlinearity of the component characteristics. This paper proposes a simple yet reliable approach to cost-efficient modelling of miniaturized microwave components which adopts two fundamental mechanisms to improve the computational efficiency of setting up the surrogate. Firstly, the model domain is confined-using a set of pre-optimized reference designs-to the region of the parameter space containing high-quality designs with respect to the relevant performance figures. Secondly, the domain is spanned by the selected principal components of the reference set for dimensionality reduction. Consequently, the surrogate model, covering wide ranges of the device parameters and operating conditions, can be established using a fraction of training data samples required by conventional approaches, without compromising its predictive power. The proposed technique is illustrated using two miniaturized microstrip components: a rat-race coupler (RRC) and an impedance matching transformer. The following accuracies of the PCA-based surrogates have been obtained: 0.9% for RRC and 2.1% for the transformer (for 800 training data samples).

  • Low-cost performance-driven modelling of compact microwave components with two-layer surrogates and gradient kriging
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2020 Full text AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS

    Utilization of electromagnetic (EM) simulation tools has become indispensable for reliable evaluation of microwave components. As the cost of an individual analysis may already be considerable, the computational overhead associated with EM-driven tasks that require massive simulations (e.g., optimization) may turn prohibitive. One of mitigation methods is the employment of equivalent network models. Yet, they are incapable of accounting for cross-coupling effects that occur in devices of complex geometries. Another option are fast replacement models (surrogates), especially the data-driven ones: readily available, generic and problem independent. Unfortunately, due to the curse of dimensionality, their applicability is limited to low-dimensional parameter spaces and narrow parameter ranges. From the utility perspective, however, the surrogate has to be valid over broad ranges of parameters and operating conditions. The recently reported performance-modeling techniques (especially nested-kriging) allow for rendering such surrogates even for complex devices. Key concept is to carry out the modeling process within a confined domain, being a subset of the parameter space that encompasses the designs of high-quality regarding the performance figures of choice. The goal of this work is to reduce the cost of reference design acquisition, which adds up to the total cost of constructing the surrogate. Toward this end, gradient-enhanced kriging is incorporated into the performance-driven modeling framework. The predictive power of the surrogates rendered using our approach by far exceeds that of the conventional methods and is comparable to the original nested kriging technique while requiring a significantly smaller number of reference designs (thus, the CPU cost). These features are demonstrated using a three-section transformer and a rat-race coupler.

  • Low-Cost Surrogate Modeling of Miniaturized Microwave Components Using Nested Kriging
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2020 APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL

    In the paper, a recently reported nested kriging methodology is employed for modeling of miniaturized microwave components. The approach is based on identifying the parameter space region that contains high-quality designs, and, subsequently, rendering the surrogate in this subset. The results obtained for a miniaturized unequal-power-split rat-race coupler and a compact three-section impedance transformer demonstrate reliability of the method even for highly-dimensional parameter spaces, as well as its superiority over conventional modeling methods.

  • Low-Power Receivers for Wireless Capacitive Coupling Transmission in 3-D-Integrated Massively Parallel CMOS Imager
    • Grzegorz Blakiewicz
    • Miron Kłosowski
    • Waldemar Jendernalik
    • Jacek Jakusz
    • Stanisław Szczepański
    2020 Full text IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS

    The paper presents pixel receivers for massively parallel transmission of video signal between capacitive coupled integrated circuits (ICs). The receivers meet the key requirements for massively parallel transmission, namely low-power consumption below a single μW, small area of less than 205 μm2, high sensitivity better than 160 mV, and good immunity to crosstalk. The receivers were implemented and measured in a 3-D IC (two face-to-face stacked chips fabricated in CMOS 180 nm process). The maximum throughput of 20 Mbps of single receiver has been achieved using a return-to-zero (RZ) code. The static and dynamic power consumption of the single receiver are below 0.2 μW and 0.3 μW/MHz, respectively. The design approach for cost-effective inter-chip massively parallel transmission of photosensor signals with pulse position modulation (PPM) has been also performed. With this approach and the developed receivers it is possible to transfer between chips 9-10 bit images at a speed of over 1k fps.

  • LSTM-based method for LOS/NLOS identification in an indoor environment
    • Alicja Olejniczak
    • Olga Błaszkiewicz
    • Krzysztof Cwalina
    • Piotr Rajchowski
    • Jarosław Sadowski
    2020

    Due to the multipath propagation, harsh indoor environment significantly impacts transmitted signals which may adversely affect the quality of the radiocommunication services, with focus on the real-time ones. This negative effect may be significantly reduced (e.g. resources management and allocation) or compensated (e.g. correction of position estimation in radiolocalisation) by the LOS/NLOS identification algorithm. This paper investigates the idea of improving already existing method of LOS/NLOS classification, based on a deep feedforward neural network, by the LSTM-based model which allows extracting and analysing time-related dependencies occurring in a radio channel.

  • Machine Learning and Text Analysis in an Artificial Intelligent System for the Training of Air Traffic Controllers
    • Tetiana Shmelova
    • Yuliya Sikirda
    • Nina Rizun
    • Vitaliy Lazorenko
    • Volodymyr Kharchenko
    2020 Full text

    This chapter presents the application of new information technology in education for the training of air traffic controllers (ATCs). Machine learning, multi-criteria decision analysis, and text analysis as the methods of artificial intelligence for ATCs training have been described. The authors have made an analysis of the International Civil Aviation Organization documents for modern principles of ATCs education. The prototype of the neural network for evaluating the timeliness and correctness of the decision making by ATCs has been developed. The new theoretical and practical tasks for simulation and pre-simulation training have been obtained using expert judgment method. The methodology for sentiment analyzing the airline customers' opinions has been proposed. In addition, the examples of artificial intelligence systems and expert systems by the authors, students and colleagues from National Aviation University, Ukraine and Gdansk University of Technology, Poland have been proposed.

  • Magnetic switching of Kerker scattering in spherical microresonators
    • Grigorios P. Zouros
    • Georgios D. Kolezas
    • Evangelos Almpanis
    • Konstantinos Baskourelos
    • Tomasz Stefański
    • Kosmas L. Tsakmakidis
    2020 Full text Nanophotonics

    Magneto-optical materials have become a key tool in functional nanophotonics, mainly due to their ability to offer active tuning between two different operational states in subwavelength structures. In the long-wavelength limit, such states may be considered as the directional forward- and back-scattering operations, due to the interplay between magnetic and electric dipolar modes, which act as equivalent Huygens sources. In this work, on the basis of full-wave electrodynamic calculations based on a rigorous volume integral equation (VIE) method, we demonstrate the feasibility of obtaining magnetically-tunable directionality inversion in spherical microresonators (THz antennas) coated by magneto-optical materials. In particular, our analysis reveals that when a high-index dielectric is coated with a magneto-optical material, we can switch the back-scattering of the whole particle to forward-scattering simply by turning off/on an external magnetic field bias. The validity of our calculations is confirmed by reproducing the above two-state operation, predicted by the VIE, with full-wave finite-element commercial software. Our results are of interest for the design of state-of-the-art active metasurfaces and metalenses, as well as for functional nanophotonic structures, and scattering and nanoantennas engineering.

  • Magnetoacoustic Heating of Plasma Caused by Periodic MagnetosoundPerturbations with Discontinuities in a Quasi-Isentropic Magnetic Gas
    • Anna Perelomova
    2020 Full text Archives of Acoustics

    The magnetoacoustic heating of plasma by harmonic or periodic saw-tooth perturbations at a trans-ducer is theoretically studied. The planar fast and slow magnetosound waves are considered. The wavevector may form an arbitrary angleθwith the equilibrium straight magnetic field. In view of variableθand plasma-β, the description of magnetosound perturbations and appropriate magnetosound heatingis fairly difficult. The scenario of heating depends not only on plasma-βandθ, but also on a balancebetween nonlinear attenuation at the shock front and inflow of energy into a system. Under some condi-tions, the average over the magnetosound period force of heating may tend to a positive or negative limit,tend to zero, or may remain constant when the distance from a transducer tends to infinity. Dynamicsof temperature specifying heating differs in thermally stable and unstable cases and occurs unusually inthe isentropically unstable flows.

  • Making full and immediate Open Access a reality through the repository route – the role of open repositories in implementation of Plan S.
    • Anna Wałek
    2020 Full text Przegląd Biblioteczny

    Thesis/Objective: In 2018, research funding institutions associated in cOAlitionS issued PlanS document which aims to accelerate the transition to full and immediate Open Access to publications from publicly funded research until January 2021. Among the recommendations, which mainly relate to publishing in the Open Access model and its financing, there are also guidelines on the implementation of Plan S assumptions through the so-called “green route”, or “repository route”. These requirements are particularly important for libraries whose role in creating tools and platforms for Open Science is crucial. One of the Coalition S member organisations is the National Science Centre (NSC), which in May 2020 introduced an Open Access policy, thus implementing the Plan S assumptions in Poland. The article presents the requirements of Plan S concerning open repositories. It defines their role in implementing the vision of openness on the example of the Bridge of Knowledge repository, created by the Gdańsk University of Technology. Research methods: The critical literature review was used to analyse the content of foreign and Polish LIS literature published in the years 2018-2020. Also, official documents issued by the European Commission were analysed, as well as websites devoted to Open Access and PlanS implementation. Results and conclusions: For research financed by cOAlition S covered by the requirements of Plan S, all peer-reviewed scientific articles must be published in locations that meet specific needs. If such an article is published at the subscription site and then immediately submitted to the Open Access repository, the requirements for repositories must also be met. Although the primary attention of the institutions implementing Plan S is focused on financing publications, especially under the so-called transformation agreements, the repository option should also be monitored and developed. It is associated with lower costs, and at the same time provides immediate open access, even to articles in subscription journals. By analysing the requirements and comparing them with the existing solutions, the repositories can be checked for compliance with Plan S. Not all criteria are, however, entirely clear to interpret and possible to implement.

  • Manufacturing of Lightweight Aggregates as an Auspicious Method of Sewage Sludge Utilization
    • Jerzy Korol
    • Marcin Głodniok
    • Aleksander Hejna
    • Tomasz Pawlik
    • Błażej Chmielnicki
    • Jan Bondaruk
    2020 Full text Materials

    : Sewage sludge is a high-volume and low-cost waste commonly generated worldwide, so its utilization is a vital issue. The application of this waste in the manufacturing of lightweight aggregates was investigated. The process was performed using intensive mixers with volumes of 5 and 30 L, as well as the industrial 500 L mixer. Then, granulates were sintered in a tube furnace. The influence of composition and mixer size on the particle size, microstructure, mechanical performance, and stability of lightweight aggregates in different environments was analyzed. The best results were obtained for a 500 L mixer, enhancing the industrial potential of the presented process. Increasing the share of sewage sludge in the composition of aggregates enhanced their porosity and reduced the specific weight, which caused a drop in compressive strength. Nevertheless, for all analyzed materials, the mechanical performance was superior compared to many commercial products. Therefore, sewage sludge can be efficiently applied as a raw material for the manufacturing of lightweight aggregates. The presented results confirm that a proper adjustment of composition allows easy the tailoring of aggregates’ performance and cost.

  • Manufacturing Parameters, Materials, and Welds Properties of Butt Friction Stir Welded Joints–Overview
    • Aleksandra Laska
    • Marek Szkodo
    2020 Full text Materials

    The modern and eco-friendly friction stir welding (FSW) method allows the combination of even such materials that are considered to be non-weldable. The development of FSW technology in recent years has allowed a rapid increase in the understanding of the mechanism of this process and made it possible to perform the first welding trials of modern polymeric and composite materials, the joining of which was previously a challenge. The following review work focuses on presenting the current state of the art on applying this method to particular groups of materials. The paper has been divided into subchapters focusing on the most frequently used construction materials, with particular emphasis on their properties, applications, and usage of the FSW method for these materials. Mechanisms of joint creation are discussed, and the microstructure of joints and the influence of material characteristics on the welding process are described. The biggest problems observed during FSW of these materials and potential causes of their occurrence are quoted. The influence of particular parameters on the properties of manufactured joints for each group of materials is discussed on the basis of a wide literature review.

  • Mapping the Structural and Dynamic Determinants of pH-Sensitive Heparin Binding to Granulocyte Macrophage Colony Stimulating Factor
    • Jennifer Cui
    • Fuming Zhang
    • Łukasz Nierzwicki
    • Giulia Palermo
    • Robert Linhardt
    • George Lisi
    2020 BIOCHEMISTRY-US

    Granulocyte macrophage colony stimulating factor (GMCSF) is an immunomodulatory cytokine that is harnessed as a therapeutic. GMCSF is known to interact with other clinically important molecules, such as heparin, suggesting that endogenous and administered GMCSF has the potential to modulate orthogonal treatment outcomes. Thus, molecular level characterization of GMCSF and its interactions with biologically active compounds is critical to understanding these mechanisms and predicting clinical consequences. Here, we dissect the biophysical factors that facilitate the GMCSF–heparin interaction, previously shown to be pH-dependent, using nuclear magnetic resonance spectroscopy, surface plasmon resonance, and molecular dynamics simulations. We find that the affinity of GMCSF for heparin increases not only with a transition to acidic pH but also with an increase in heparin chain length. Changes in local flexibility, including a disruption of the N-terminal helix at acidic pH, also accompany the binding of heparin to GMCSF. We use molecular dynamics simulations to propose a mechanism in which a positive binding pocket that is not fully solvent accessible at neutral pH becomes more accessible at acidic pH, facilitating the binding of heparin to the protein.

  • Mapping the Transglycosylation Relevant Sites of Cold-Adapted β-D-Galactosidase from Arthrobacter sp. 32cB
    • Maria Rutkiewicz
    • Marta Wanarska
    • Anna Bujacz
    2020 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    B-Galactosidase from Arthrobacter sp. 32cB (ArthbetaDG) is a cold-adapted enzyme able to catalyze hydrolysis of beta-D-galactosides and transglycosylation reaction, where galactosyl moiety is being transferred onto an acceptor larger than a water molecule. Mutants of ArthbetaDG D207A and E517Q were designed to determine the significance of specific residues and to enable formation of complexes with lactulose and sucrose and to shed light onto the structural basis of the transglycosylation reaction. The catalytic assays proved loss of function mutation E517 into glutamine and a significant drop of activity for mutation of D207 into alanine. Solving crystal structures of two new mutants, and new complex structures of previously presented mutant E441Q enables description of introduced changes within active site of enzyme and determining the importance of mutated residues for active site size and character. Furthermore, usage of mutants with diminished and abolished enzymatic activity enabled solving six complex structures with galactose, lactulose or sucrose bounds. As a result, not only the galactose binding sites were mapped on the enzyme’s surface but also the mode of lactulose, product of transglycosylation reaction, and binding within the enzyme’s active site were determined and the glucopyranose binding site in the distal of active site was discovered. The latter two especially show structural details of transglycosylation, providing valuable information that may be used for engineering of ArthbetaDG or other analogous galactosidases belonging to GH2 family.

  • Maritime Communications Network Development Using Virtualised Network Slicing of 5G Network
    • Sławomir Gajewski
    2020 Full text Nase More

    The paper presents the review on perspectives of maritime systems development at the context of 5G systems implementation and their main properties. Firstly, 5G systems requirements and principles are discussed, which can be important for maritime applications. Secondly, the problems of network softwarisation, virtualisation and slicing, and possible types of services for potential implementation in 5G marine applications are described. Next, the proposed model for network slicing dedicated to maritime systems is discussed, and 5G maritime systems architectures, including both terrestrial and satellite communications, are presented. The goal of the paper is to present the actual state of the art of 5G solutions for maritime applications as well as the analysis of network slicing and virtualisation for marine services implementation. The paper is based on original author contribution for network slicing models dedicated to marine applications which has not been previously published anywhere.

  • Mark Fisher: między krytyką kultury a libidynalną ekonomią polityczną
    • Andrzej Karalus
    2020

    Artykuł omawia dorobek Marka Fishera, znanego brytyjskiego krytyka kultury i filozofa, autora głośnej książki Capitalist Realism. Autor artykułu krótko rekapituluje główne tezy jego książki oraz omawia samą koncepcję "realizmu kapitalistycznego", porusza również te zagadnienia, które nie doczekały się teoretycznej artykulacji bądź były analizowane w innych książkach i artykułach Fishera. Zagadnienia te to: libidinalna ekonomia polityczna późnego kapitalizmu, anihilacja czasowości i poczucia linearności czasu oraz kwestia uwiądu energii utopijnych we współczesnej kulturze.

  • Market Structure and Market Power in Selected Sectors of The Polish Economy Based on COICOP Classification
    • Paweł Umiński
    2020

    This paper present new and simple measures of market structure and market power. Based on the classical models of market structures, where a given structure is determined by the number of enterprises, indexes of degree of monopoly have been estimated, representing an average number of entities per branch. Additionally, market power indexes have been determined as an average revenue per an enterprise in a given branch. This approach has been employed to the analysis of market structure and market power in the Polish economy in the period from 2001 to 2013, according to COICOP classification. The obtained results indicate that both market structures and market power of companies are quite diversified. Classes with large number of entities, e.g. Medical Services and low number of entities (Gas) could be indicated. Market power is also diversified – relatively low rates occurred in Medical Services class, while the highest rates were determined for Fuels class. The conclusions from the analysis imply that in many sectors with considerable market power, State Treasury is highly significant. Established measure of market power was compared with the well-known measures – Lerner's index and HHI. Correlation coefficients indicate that the relation is statistically significant but moderate or weak.

  • Marketing relacji we współczesnym świecie
    • Anna Drapińska
    2020

    Teoria i praktyka marketingu ulegają ciągłej ewolucji, podążając za zmianami gospodarczymi, społecznymi oraz technologicznymi i dostosowując się do nich. Obecne trendy, które napędzają zmiany w globalnym świecie biznesu powodują, że silne relacje z klientami są bardziej niż kiedykolwiek, niezbędne dla strategii firm, które chcą osiągać przewagę konkurencyjną. Nowe warunki działania przedsiębiorstw to również świat, w którym miesza się rzeczywistość online i offline. Przedsiębiorstwa muszą odna¬leźć w tym świecie własną drogę, która pozwoli im na wzmocnienie swojej po¬zycji na rynku. Taką propozycję stanowi marketing relacji, którego istotą jest budowanie długookresowych, korzystnych dla obu stron relacji z klientami i partnerami, opartych na obopólnym zadowoleniu, zaufaniu i współdziałaniu. Celem niniejszej książki jest zebranie najważniejszej dotychczasowej – ciągle aktualnej – wiedzy dotyczącej marketingu relacji, a także jej wzbogacenie, zwłasz¬cza w kontekście nowej, wirtualnej rzeczywistości i rozwijających się działań w ob¬szarze online. Książka składa się z czterech rozdziałów. W pierwszym opisano korzenie i ewolucję marketingu relacji, a także trendy umacniające pozycję tej koncepcji we współczesnym świecie. Odniesiono się także do koncepcji po¬krewnych, jakim są marketing doświadczeń i zarządzanie relacjami z klientami (CRM). Rozdział drugi koncentruje się na dogłębnym wyjaśnieniu pojęcia relacji i lojal¬ności. W rozdziale trzecim opisane zostały wybrane determinanty relacji. Skoncentrowano się tu na budowa¬niu zadowolenia, a także na zaufaniu i zaangażowaniu. Scharakteryzowano również przekaz ustny (word-of-mouth) jako jedną z najistot¬niejszych obecnie form komunikacji oraz jego nową, elektroniczną fomę (eWOM). Ostatni rozdział skupia się na współczesnym kliencie. Opisano tu proces współtworzenia wartości, pokazano nowe ścieżki zakupowe klientów, które co¬raz częściej przeplatają w sobie elementy świata offline i online. Zaprezentowano także genezę i charakterystykę marketingu relacji w świecie cyfrowym. Książka kończy się autorską propozycją koncepcji współczesnego marketingu relacji, któ¬ry powinien odpowiadać na potrzebę partnerskiego traktowania klientów. Zwró¬cenie się ku autentycznym potrzebom, zaspokajanym w uczciwy i rzetelny sposób, pewność, że dana firma jest godna zaufania i wykazuje rzeczywistą troskę o swo¬ich klientów, mogą się stać najważniejszymi atutami prowadzącymi do lojalności klientów i przewagi konkurencyjnej

  • Material Identification of the Human Abdominal Wall Based On the Isogeometric Shell Model
    • Bartosz Borzeszkowski
    • Thang X. Duong
    • Izabela Lubowiecka
    • Roger Sauer
    2020

    The human abdominal wall is an object of interest to the research community in the context of ventral hernia repair. Computer models require a priori knowledge of constitutive parameters in order to establish its mechanical response. In this work, the Finite Element Model Updating (FEMU) method is used to identify an heterogeneous shear modulus distribution for a human abdominal wall model, which is based on nonlinear isogeometric Kirchhoff-Love shell formulation and the geometry obtained experimentally. Displacements on the boundary are fixed, and an intraperitoneal pressure of 1600 Pa is applied. A hyperelastic Koiter-Gasser-Ogden-Holzapfel shell material model is used. The heterogeneous distribution of the shear modulus is interpolated by 24 nodal values. The inverse solution is obtained by the minimization of the objective function, based on the difference between the deformation obtained from the analysis and the experiment – here an experiment-like FE solution with prescribed reference material distribution, and addition of Gaussian noise. The mean relative error between reference solution and identified parameters is 1.34 %, while stress and bending moments deviations are below 0.01%.

  • Material Parameters Identification of Historic Lighthouse Based on Operational Modal Analysis
    • Agnieszka Tomaszewska
    • Milena Drozdowska
    • Marek Szafrański
    2020 Full text Materials

    In the present paper, the identification of the material parameters of a masonry lighthouse is discussed. A fully non-invasive method was selected, in which the material properties were determined via numerical model validation applied to the first pair of natural frequencies and their related mode shapes, determined experimentally. The exact structural model was built by means of the finite element method. To obtain experimental data for the inverse analysis, operational modal analysis was applied to the structure. Three methods were considered: peak picking (PP), eigensystem realization algorithm (ERA) and natural excitation technique with ERA (NExT-ERA). The acceleration’s responses to environmental excitations, enhanced in some periods of time by sheet piling hammering or by sudden interruptions like wind stroke, were assumed within the analysis input. Different combinations of the input were considered in the PP and NExT-ERA analysis to find the most reasonable modal forms. A number of time periods of a free-decay character were considered in the ERA technique to finally calculate the averaged modal forms. Finally, the elastic modulus, Poisson’s ratio and material density of brick, sandstone and granite masonry were determined. The obtained values supplement the state of the art database concerning historic building materials. In addition, the numerical model obtained in the analysis may be used in further cases of structural analysis.

  • Materiały biologiczne pochodzące od ptaków morskich oraz renifera Svalbardzkiego, jako źródło informacji o zanieczyszczeniu środowiska polarnego
    • Aneta Pacyna-Kuchta
    2020 Full text

    Wykorzystanie nie-destrukcyjnie pobranych tkanek takich jak sierść oraz pióra umożliwia pobieranie próbek od żywych osobników, nie naruszając struktury populacji oraz kwestii moralnych związanych z odłowem. W związku z tym możliwe jest śledzenie zmian spowodowanych podwyższonym poziomem zanieczyszczeń. W ostatnich latach, wykorzystanie próbek pobranych nie-destrukcyjnie staje się istotną częścią badań środowiskowych. Poziomy zanieczyszczeń różnią się w zależności od rodzaju tkanki i ich zdolności do akumulacji związków, co ma wpływ na wiarygodny monitoring. Przykładowo tkanka skeratynizowana, taka jak pióro stanowi źródło informacji o elementach obecnych we krwi podczas jego wzrostu. Kiedy krew jest dostarczana do pióra, związki o wysokim powinowactwie do grup funkcyjnych keratyny wiążą się z wiązaniami disiarczkowymi zawartymi w strukturze pióra. Kiedy piórko jest w pełni uformowane, naczynie krwionośne zanika, i pióro zostaje odizolowane od dalszego pobierania związków chemicznych. W badaniach będących podstawą rozprawy doktorskiej wykorzystane zostały próbki pobrane nie-destrukcyjnie od kluczowych gatunków polarnego ekosystemu morskiego oraz lądowego. Ekosystem morski jest reprezentowany przez trzy gatunki ptaków morskich: oceannika czarnobrzuchego i żółtopłetwego oraz alczyka. Ptaki morskie odgrywają szczególną role w środowisku, i są jednym z bardziej charakterystycznych części polarnego środowiska morskiego. Gatunki lądowe są rzadziej badaną, jednak szczególnie ważną częścią ekosystemu polarnego. Renifer Svalbardzki jest jedynym dużym ssakiem roślinożernym zamieszkującym obszar Arktyki Europejskiej. Analizy wykonane zostały pod kątem obecności wybranych metali, nie-metali oraz metalloidów (wykonane przy zastosowaniu ICP-MS, ICP-OES, Bezpośredniego Analizatora Rtęci) głównie w tkankach skeratynizowanych (pióra oraz sierść) oraz dodatkowo w odchodach renifera oraz skorupkach powylęgowych alczyka. Próbki sierści dodatkowo przeanalizowano pod kątem obecności polichlorowanych bifenyli, wielopierścieniowych węglowodorów aromatycznych oraz pestycydów chloroorganicznych (przy zastosowaniu GC-MS/MS). Badania są dowodem, iż materiały biologiczne pobrane w sposób nie-destrukcyjny stanowią cenne źródło informacji w badaniach ekotoksykologicznych, i mogą być szczególnie użyteczne w przypadku chronionych gatunków polarnych.

  • Mathematical modelling and computer simulation of activated sludge systems.Second edition
    • Jacek Mąkinia
    • Ewa Zaborowska
    2020

    Mathematical Modelling and Computer Simulation of Activated Sludge Systems – Second Edition, provides, from the process engineering perspective, a comprehensive and up-to-date overview regarding various aspects of the mechanistic (“white box”) modelling and simulation of advanced activated sludge systems performing biological nutrient removal. In the new edition of the book, a special focus is given to nitrogen removal and an overview of the latest developments in modelling the innovative nitrogen removal processes is provided. Furthermore, a new section on micropollutant removal has been added. The focus of modelling has been shifting in the last years to models that can describe the performance of a whole plant (plant-wide modelling). The expanded part of this new edition introduces models describing the most important processes interrelated with the mainstream activated sludge systems as well as models describing the energy balance, operating costs and environmental impact. The complex process evaluation, including minimization of energy consumption and carbon footprint, is in line with the present and future wastewater treatment goals. By combining a general introduction and a textbook, this book serves both intermediate and more experienced model users, both researchers and practitioners, as a comprehensive guide to modeling and simulation studies. The book can be used as a supplemental material at graduate and post-graduate levels of wastewater engineering/modelling courses.

  • Mathematical Modelling of Drive System with an Elastic Coupling Based on Formal Analogy between the Transmission Shaft and the Electric Transmission Line
    • Andrzej Popenda
    • Marek Lis
    • Marcjan Nowak
    • Krzysztof Blecharz
    2020 Full text ENERGIES

    In the paper, the kinematic structure of the transmission shaft between the driving motor and the working mechanism is studied. The analysis is based on electrical and mechanical similarities. The equivalent circuits, typical for electrical systems, are defined for the transmission shaft concerned. Modelling of the transmission shaft based on a formal analogy between the transmission shaft and the electric transmission line is also proposed. The results of a computer simulation and experimental test are presented. The results confirm the high conformity of the proposed mathematical model with the physical object.

  • Measurement of expenditure efficiency of Polish cities with county rights in the context of quality of life
    • Alicja Sekuła
    2020 Full text

    The article is devoted to the measurement of efficiency of overall expenditures. The purpose of the study is to evaluate the efficiency of use of budget resources by local government units in the context of fostering quality of life. The subject of the study is 65 Polish cities with county rights (county status). Calculations were carried out using Data Envelopment Analysis (DEA). The results of analysis confirm the two research hypotheses: the efficiency of budget expenditures is higher in larger cities with county rights (status), and the efficiency of budget expenditures is higher in cities with county rights (status) with lower overall per capita expenditures.

  • Measurements of Activity Coefficients at Infinite Dilution for Organic Solutes in the Ionic Liquids N-Ethyl- and N-Octyl-N-methylmorpholinium Bis(trifluoromethanesulfonyl)imide. A Useful Tool for Solvent Selection
    • Łukasz Marcinkowski
    • Joachim Eichenlaub
    • Elham Ghasemi
    • Żaneta Polkowska
    • Adam Kloskowski
    2020 Full text MOLECULES

    In recent years, many papers describing ionic liquids (IL) as promising solvents in separation techniques have been published. The conscious choice of appropriate ionic liquid as absorption media in effective extraction of selected types of analytes requires deeper understanding of the analyte−IL interactions. Therefore, intensive research is conducted to determine the values of activity coefficient at infinite dilution, which allows us to characterize the nature of these interactions. Based on the inverse gas chromatography retention data, activity coefficients at infinite dilution γ∞13 of 48 different organic compounds in the ionic liquids N-ethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide [C2C1Mor][TFSI] and N-octyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide [C8C1Mor][TFSI] were determined. The measurements covered a broad range of volatile organic compounds, including n-alkanes, n-alkenes, n-alkynes, alcohols, aldehydes, ketones, aromatic compounds and common polar solvents, representing different types of interactions. Activity coefficients at infinite dilution were measured in the temperature range from 313.15 to 363.15 K. The excess partial molar enthalpies and entropies at infinite dilution were determined. Selectivity at infinite dilution was also calculated for exemplary separation processes in the hexane/benzene system. The obtained results were analyzed and compared with literature data for ionic liquids containing the same anion [TFSI]¯ and different cations. The study results indicate that some potential applications of the investigated ionic liquids in separation problems exist.

  • Measurements of displacement and acceleration of the railway bridge at km 333-254 of the Vilnius - Klaipeda railway line
    • Adam Nadolny
    • Łukasz Filar
    • Jerzy Kałuża
    • Marek Wazowski
    • Mikołaj Miśkiewicz
    • Jacek Chróścielewski
    • Krzysztof Wilde
    • Łukasz Pyrzowski
    • Paweł Tysiąc
    • Bartosz Sobczyk
    • Karolina Makowska
    2020

    The purpose of this work is to perform a report of static and dynamic test realized on the bridge at km 333-254 of the Vilnius - Klaipeda railway line over the Salantas River in Kūlupėnų.

  • Mechanical and Corrosion Properties of Laser Surface-Treated Ti13Nb13Zr Alloy with MWCNTs Coatings
    • Beata Majkowska-Marzec
    • Patryk Tęczar
    • Michał Bartmański
    • Bartosz Bartosewicz
    • Bartłomiej J. Jankiewicz
    2020 Full text Materials

    : Titanium and its alloys is the main group of materials used in prosthetics and implantology. Despite their popularity and many advantages associated with their biocompatibility, these materials have a few significant disadvantages. These include low biologic activity—which reduces the growth of fibrous tissue and allows loosening of the prosthesis—the possibility of metallosis and related inflammation or other allergic reactions, as well as abrasion of the material during operation. Searching for the best combinations of material properties for implants in today0 s world is not only associated with research on new alloys, but primarily with the modification of their surface layers. The proposed laser modification of the Ti13Nb13Zr alloy with a carbon nanotube coating is aimed at eliminating most of the problems mentioned above. The carbon coating was carried out by electrophoretic deposition (EPD) onto ground and etched substrates. This form of carbon was used due to the confirmed biocompatibility with the human body and the ability to create titanium carbides after laser treatment. The EPD-deposited carbon nanotube coating was subjected to laser treatment. Due to high power densities applied to the material during laser treatment, non-equilibrium structures were observed while improving mechanical and anti-corrosive properties. An electrophoretically deposited coating of carbon nanotubes further improved the effects of laser processing through greater strengthening, hardness or Young0 s modulus similar to that required, as well as led to an increase in corrosion resistance. The advantage of the presented laser modification of the Ti13Nb13Zr alloy with a carbon coating is the lack of surface cracks, which are difficult to eliminate with traditional laser treatment of Ti alloys. All samples tested showed contact angles between 46◦ and 82◦ and thus, based on the literature reports, they have hydrophilic surfaces suitable for cell adhesion.

  • Mechanical and Microstructural Characterization of TIG Welded Dissimilar Joints between 304L Austenitic Stainless Steel and Incoloy 800HT Nickel Alloy
    • Grzegorz Rogalski
    • Aleksandra Świerczyńska
    • Michał Landowski
    • Dariusz Fydrych
    2020 Full text Metals

    In this article, the mechanical properties and microstructure of 304L austenitic stainless steel/Incoloy 800HT nickel alloy dissimilar welded joints are investigated. The joints were made of 21.3 mm × 7.47 mm tubes using the TIG process with the use of S Ni 6082 nickel filler metal. No welding imperfections were found and high strength properties of joints were obtained, meeting the assumed acceptance criteria of the product’s standards. The tensile strength of the welded joints was higher than for the joined materials (Incoloy 800HT). Macro- and microscopic metallographic tests revealed the correct morphology of the joints and the appropriate structures in their critical zones. However, differences were found in the morphologies of the zones between the weld and the base materials. In fusion boundary from the side of the Incoloy 800HT alloy, no clear outline of the fusion line was observed (type A fusion boundary), while increased grain size and an epitaxial structure were observed. In turn, in the zone: weld–304L steel, a distinct fusion line was observed with areas with an increased amount of high-temperature δ ferrite (type B fusion boundary). No precipitates were found that could reduce the resistance of the joints to intergranular corrosion. A hardness decrease (approximately 30 HV0.1) in the transition zone: austenitic steel–weld and an increase of hardness (approximately 10 HV0.1) on the opposite side of the welded joint were observed.

  • Mechanical and radiation shielding properties of concrete reinforced with boron--basalt fibers using Digital Image Correlation and X--ray micro--computed tomography
    • Łukasz Skarżyński
    2020 Full text CONSTRUCTION AND BUILDING MATERIALS

    The paper presents experimental investigations of the radiation shielding, mechanical and fracture properties of concrete reinforced with 5 kg/m3 of novel basalt fibers infused with boron oxide (BBF). However, further studies concerning other dosages i.e. 1 kg/m3, 10 kg/m3, 15 kg/m3 and 20 kg/m3 are currently carried out. Experiments with neutron source revealed that addition of BBF as a dispersed concrete reinforcement could improve the neutron radiation shielding of plain concrete by up to 25%. On the basis of mechanical tests, it turned out that compressive strength, tensile splitting strength and flexural of concrete reinforced with BBF were lower by up to 15% than analogous values for plain concrete. Simultaneously, shrinkage strain of BBF concrete was lower by about 10% than of plain concrete. Fracture process zone development on the surface of samples was investigated by Digital Image Correlation (DIC) using camera with the 36 megapixel matrix that allowed to obtain pixel size of 18 µm resulting in the length resolution equal approximately 60 pixel/mm whereas analyses of 3D material micro-structure, air voids, width and curvature of crack were carried out by X-ray micro-computed tomography (micro-CT) with 0.2 mm brass filter, voltage and the current equal 130 keV and 61 µA, respectively. The voxel size of the X-ray micro-CT was 39.68 microns. Experiments revealed that basalt fibers infused with boron oxide as a concrete dispersed reinforcement improved the ability of limiting micro-cracking area and bridging macro-cracking by up to 28%.

  • Mechanical and structural investigations of wings of selected insect species
    • Michał Landowski
    • Zuzanna Kunicka-kowalska
    • Krzysztof Sibilski
    2020 Full text Acta of Bioengineering and Biomechanics

    This paper presents research and measurements leading to obtaining the Young’s modulus of wing bearing structures of selected insect species. A small testing machine intended for three-point bending and equipped with instruments registering low forces was constructed for the needs of the experiment. The machine was used to perform numerous bending tests of wings of three species of insects (obtained from a breeding farm): Attacus atlas, Vespa crabro, Libellula Depressa at various air-humidity conditions. Values of the force and displacement obtained in the course of the tests were used to calculate Young’s modulus. In order to do so, it was also necessary to obtain the moment of inertia of the wing cross-section. These values were measured on the basis of the images obtained with a SEM microscope. Obtained results were averaged and presented with a breakdown by air-humidity conditions. It was observed that Young’s modulus decreased with an increase of humidity, hence the calculations of the percentage decrease of this mechanical parameter were performed. Obtained results were compared with the observed structure which was also presented under light microscope. It transpired that the construction of a wing does not only influence the mechanical values but also it influences their susceptibility to the changes occurring in the environment. Thereby, differences between Lepidoptera and Hymenoptera insects were indicated also within the aspect discussed in this paper.

  • Mechanical exfoliation and layer number identification of single crystal monoclinic CrCl3
    • S Kazim
    • M Alì
    • S Palleschi
    • G D’Olimpio
    • D Mastrippolito
    • A Politano
    • Roberto Gunnella
    • Andrea DiCicco
    • M Renzelli
    • G Moccia
    • O A Cacioppo
    • R Alfonsetti
    • Judyta Strychalska-Nowak
    • Tomasz Klimczuk
    • R. J. Cava
    • Luca Ottaviano
    2020 NANOTECHNOLOGY

    After the recent finding that CrI3, displays ferromagnetic order down to its monolayer, extensive studies have followed to pursue new two-dimensional (2D) magnetic materials. In this article, we report on the growth of single crystal CrCl3 in the layered monoclinic phase. The system after mechanical exfoliation exhibits stability in ambient air (the degradation occurs on a time scale at least four orders of magnitude longer than is observed for CrI3). By means of mechanical cleavage and atomic force microscopy (AFM) combined with optical identification, we demonstrate the systematic isolation of single and few layer flakes onto 270 nm and 285 nm SiO2/Si (100) substrates with lateral size larger than graphene flakes isolated with the same method. The layer number identification has been carried with statistically significant data, quantifying the optical contrast as a function of the number of layers for up to six layers. Layer dependent optical contrast data have been fitted within the Fresnel equation formalism determining the real and imaginary part of the wavelength dependent refractive index of the material. A layer dependent (532 nm) micro-Raman study has been carried out down to two layers with no detectable spectral shifts as a function of the layer number and with respect to the bulk.

  • Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder
    • Olga Mysiukiewicz
    • Paulina Kosmela
    • Mateusz Barczewski
    • Aleksander Hejna
    2020 Full text Materials

    Investigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry), thermal (differential scanning calorimetry), as well as static (tensile tests, hardness, rebound resilience) and dynamic (dynamical mechanical analysis) mechanical properties of composites were investigated. The incorporation of 1 and 2 wt% of aluminum filler resulted in small enhancements of mechanical properties, while loadings of 5 and 10 wt% provided materials with a similar performance to neat HDPE. Such results were supported by the lack of disturbances in the rheological behavior of composites. The presented results indicate that a significant content of aluminum filler may be introduced into the HDPE matrix without additional pre-treatment and does not cause the deterioration of composites’ performance, which should be considered beneficial when engineering PE/metal composites.

  • Mechanical-Level Hardware-In-The-Loop and Simulation in Validation Testing of Prototype Tower Crane Drives
    • Michał Michna
    • Filip Kutt
    • Łukasz Sienkiewicz
    • Roland Ryndzionek
    • Grzegorz Kostro
    • Dariusz Karkosiński
    • Bartłomiej Grochowski
    2020 Full text ENERGIES

    In this paper, the static and dynamic simulations, and mechanical-level Hardware-In-the-Loop (MHIL) laboratory testing methodology of prototype drive systems with energy-saving permanent-magnet electric motors, intended for use in modern construction cranes is proposed and described. This research was aimed at designing and constructing a new type of tower crane by Krupiński Cranes Company. The described research stage was necessary for validation of the selection of the drive system elements and confirmation of its compliance with applicable standards. The mechanical construction of the crane was not completed and unavailable at the time of testing. A verification of drive system parameters had to be performed in MHIL laboratory testing, in which it would be possible to simulate torque acting on the motor shaft. It was shown that the HIL simulation for a crane may be accurate and an effective approach in the development phase. The experimental tests of selected operating cycles of prototype crane drives were carried out. Experimental research was performed in the LINTE^2 laboratory of the Gdańsk University of Technology (Poland), where the MHIL simulator was developed. The most important component of the system was the dynamometer and its control system. Specialized software to control the dynamometer and to emulate the load subjected to the crane was developed. A series of tests related to electric motor environmental parameters was carried out.

  • Mechaniczne Metody Badań Materiałów
    • Wiktoria Wojnicz
    • Edmund Wittbrodt
    2020 Full text

    W podręczniku zawarto opis Laboratorium Wytrzymałości Materiałów znajdującego się w Katedrze Mechaniki i Mechatroniki na Wydziale Mechanicznym Politechniki Gdańskiej oraz instrukcje do szesnastu ćwiczeń laboratoryjnych dla studentów wszystkich kierunków studiów oferowanych na Wydziale. Ćwiczenia dotyczą zagadnień związanych ze statycznymi i dynamicznymi próbami niszczącymi, badań materiałów na ściskanie i rozciąganie, badań twardości, udarności, wytrzymałości zmęczeniowej i propagacji pęknięcia zmęczeniowego oraz badań lin stalowych, prób technologicznych i badań niszczących złączy spawanych metali. Są to badania odnoszące się do metali pracujących nie tylko w temperaturze otoczenia, ale także w podwyższonej temperaturze. W opisach poszczególnych ćwiczeń podano cel prowadzonych badań, podstawowe definicje, metody realizacji badań ze szczególnym omówieniem próbek do badań, maszyn i urządzeń wytrzymałościowych niezbędnych do realizacji badań oraz sposobu analizy i opracowywania wyników. Podano również wykaz polskich i europejskich norm, według których prowadzone są badania.

  • Mechanizm współpracy z gruntem pali prefabrykowanych wbijanych w świetle próbnych obciążeń pali oprzyrządowanych
    • Adam Krasiński
    • Kazimierz Gwizdała
    • Tomasz Kusio
    • Paweł Więcławski
    • Mateusz Wiszniewski
    2020 Full text Inżynieria Morska i Geotechnika

    Opis badań i wyniki próbnych obciążeń statycznych dwóch pali prefabrykowanych wbijanych oprzyrządowanych w aparaturę do pomiaru rozkładu siły osiowej wzdłuż trzonu pala. Analiza wpływu czasu i procesu wbijania na charakterystykę osiadania pali prefabrykowanych wbijanych. Identyfikacja siły rezydualnej w palu prefabrykowanym wbijanym i jej wpływ na interpretację pomiarów ekstensometrycznych w próbnym obciążeniu pala. Wnioski na temat problemów w interpretacji wyników badań pali prefabrykowanych wbijanych oprzyrządowanych pomiarowo.

  • Membrane technologies assisting plant-based and agro-food by-products processing: A comprehensive review
    • Roberto Castro-Muñoz
    • Grzegorz Boczkaj
    • Emilia Gontarek
    • Alfredo Cassano
    • Vlastimil Fíla
    2020 Full text TRENDS IN FOOD SCIENCE & TECHNOLOGY

    Background Nowadays, membrane-based technologies (e.g. microfiltration, ultrafiltration, nanofiltration, membrane distillation, and pervaporation) have demonstrated to meet the requirements to be involved in different food and bioproduct processes. Scope and approach Several applications have been developed, including either separation, recovery or concentration of bioactive molecules from agro-food products and by-products, treatment of natural extracts, recovery of aromas from natural and processed products, production of non-alcoholic beverages, as the most popular ones. Therefore, the goal of this review is to give a comprehensive outlook of the latest developments focused on the separation, fractionation and concentration of several bioactive compounds contained in their original sources, as well as the food processes-assisted by membrane technologies. Key findings and conclusions Throughout this review, ongoing literature has been analysed, discussing the relevant insights according to the type of membrane-based separation process, properties of molecules, membrane features and key factors influencing the separation performance of those technologies. Specific applications have been analysed and discussed, highlighting typical advantages and drawbacks over conventional technologies.

  • Membranes for toxic- and heavy-metal removal
    • Roberto Castro-Muñoz
    • Emilia Gontarek
    • Alberto Figoli
    2020

    Since time ago, membranes have greatly attracted the attention of researchers for different types of water-treatment applications, such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, and heavy metals. Nowadays, one of the current challenges of research community definitely deals with the removal of toxic and heavy metals from water. In this regard, the current chapter provides enough inputs about the current advances and approaches of the use of membranes for such removal task, thereby addressing the highlighted literature survey of using polymeric and nanocomposite membranes for heavy-metal removal. Moreover, it gives up-to-date information related to those novel nanocomposite membranes and their contribution for water-treatment applications.

  • Meso-mechanical modelling of damage in concrete using discrete element method with porous ITZs of defined width around aggregates.
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    2020 Full text ENGINEERING FRACTURE MECHANICS

    Artykuł omawia wyniki obliczeń numerycznych pękania dla betonu stosując metodę elementów dyskretnych. Beton był opisany jako materiał 4-fazowy i był poddany zginaniu. W obliczeniach uwzględniono strefy ITZ o skończonej szerokości dookoła wszystkich ziaren kruszywa. Nacisk położono na przebieg mikropęknięć przy kruszywie. Wyniki porównano bezpośrednio z doświadczeniami. Obliczenia wykonano także dla szorstkich ziaren kruszywa. Wyniki zaprezentowane w artykule oferują nową perspektywę w zrozumieniu procesu powstawanie pęknięć w obciążonym betonie.

  • Mesophilic and thermophilic dark fermentation course analysis using sensor matrices and chromatographic techniques
    • Edyta Słupek
    • Patrycja Makoś
    • Karolina Kucharska
    • Jacek Gębicki
    2020 Full text CHEMICAL PAPERS

    Production of biofuels from biomass is expected to benefit the society and the environment. At present, bio waste residues processing includes hydrolysis, dark fermentation, photofermentation, pyrolysis, gasification, and chemical synthesis. As the composition and the chemical structure of organic substances affect the efficiency of mentioned processes, it is believed that the glucose concentration is a crucial parameter for the evaluation of the efficiency of biological processes. Also, the control of by-products formulated during each stage of biomass processing affects the course of dark fermentation. Therefore, model processes regarding mesophilic and thermophilic dark fermentation were carried out. Glucose as a sole carbon source was applied as the fermentation broth and Faloye-pretreated activated municipal wastewater sludge was introduced as the source of sporulating microorganisms. Production of hydrogen and methane was controlled by means of sensor matrices. Obtained results are comparable to those obtained using the standard method based on gas chromatography and indicate the suitability of their application for online routine analyses of hydrogen and methane during fermentation processes. In addition, the fermentation broth was also examined by means of gas and liquid chromatography in the scope of glucose reduction, and generation of volatile fatty acids and phenols.

  • Metal ion directed template synthesis using 2-acetyl-1,3-indandione and ethylenediamine: steric and electronic restrictions
    • Anife Ahmedova
    • Sonya Zareva
    • Anna Dołęga
    2020 MENDELEEV COMMUNICATIONS

    A template synthesis using 2-acetyl-1,3-indandione and ethylenediamine results in formation of octahedral Ni complex, whose crystal structure has been resolved using single crystal X-ray diffraction. The structure indicates that only exocyclic enolic oxygen atom of the triketone takes part in the condensation with ethylenediamine.

  • Metal-Organic Framework (MOF)/Epoxy Coatings: A Review
    • Farzad Seidi
    • Maryam Jouyandeh
    • Mohsen Taghizadeh
    • Ali Taghizadeh
    • Henri Vahabi
    • Sajjad Habibzadeh
    • Krzysztof Formela
    • Mohammad Saeb
    2020 Full text Materials

    Epoxy coatings are developing fast in order to meet the requirements of advanced materials and systems. Progress in nanomaterial science and technology has opened a new era of engineering for tailoring the bulk and surface properties of organic coatings, e.g., adhesion to the substrate, anti-corrosion, mechanical, flame-retardant, and self-healing characteristics. Metal-organic frameworks (MOFs), a subclass of coordinative polymers with porous microstructures, have been widely synthesized in recent years and applied in gas and energy storage, separation, sensing, environmental science and technology, and medicine. Nevertheless, less attention has been paid to their performance in coatings. Well-known as micro- and nanoporous materials, with a tailorable structure consisting of metal ions and organic linkers, MOFs have a huge loading capacity, which is essential for the delivery of corrosion inhibitors. This review paper attempts to highlight the importance of epoxy/MOF composites for coating applications. A particular emphasis was explicitly placed on the anti-corrosion, flame-retardant, mechanical, and dielectric properties of epoxy/MOF coatings.

  • Method of estimating the rolling resistance coefficient of vehicle tyre using the roller dynamometer
    • Adrian Soica
    • Adian Budala
    • Vlad Monescu
    • Sławomir Sommer
    • Wojciech Owczarzak
    2020 PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING

    The tendency in the past few years has been to introduce tyres with lower rolling resistance coefficients to the market. This paper presents a mathematical method for determining the rolling resistance coefficients variation depending on the speed. The method uses power balance which results from automobile dynamics while rolling on chassis dynamometer. The rolling resistance coefficients of tyres obtained through ‘drum test method’, for which the rolling resistance coefficients variation is known in terms of vehicle speed, are considered as reference values, while than rolling resistance coefficients of tyres obtained through ‘MAHA roller dynamometer’ using the recorded lost drag power in the roll-out phase on the stand are considered as tested values. The rolling resistance coefficients variation could be determined up to the maximum permissible speed of the tyre, for all wheels trained on the stand and not just for one tyre, as determined in laboratory conditions. The test conditions are similar to those in real road conditions, where the temperature of the environment and wheels cannot be controlled. The values obtained by the authors’ proposed method were compared with the values obtained by the ‘drum test method’. The main contribution of the proposed method is to estimate the rolling resistance coefficients without using a very expensive test facility.

  • Methodology for Carrying Out Measurements of the Tombolo Geomorphic Landform Using Unmanned Aerial and Surface Vehicles near Sopot Pier, Poland
    • Cezary Specht
    • Oktawia Lewicka
    • Mariusz Specht
    • Paweł Dąbrowski
    • Paweł Burdziakowski
    2020 Full text Journal of Marine Science and Engineering

    The human impact on the ecosystem has been particularly evident in the last century; it transforms the Earth’s surface on an unprecedented scale and brings about irreversible changes. One example is an oceanographic phenomenon known as a tombolo, i.e., a narrow belt connecting the mainland with an island lying near the shore formed as a result of sand and gravel being deposited by sea currents. The phenomenon contributes to an increase in the biogenic substance content in the littoral zone, which leads to increased cyanobacteria blooming in the summer period. Moreover, the debris accumulation in the littoral zone results in the mud formation, which makes the beach landscape less attractive. One of the main features of the tombolo phenomenon is its variability of shape, which includes the form of both the shore and the seabed adjacent to it. Therefore, to describe its size and spatio-temporal variability, it is necessary to apply methods for geodetic (the land) and hydrographic (the sea) measurements that can be carried out in different ways. The aim of the paper is to present the methodology for carrying out measurements of the tombolo oceanographic phenomenon using Unmanned Aerial Vehicles (UAV) and Unmanned Surface Vehicles (USV) on the example of a waterbody adjacent to the Sopot pier. It also presents the results of surveys carried out in November 2019 within this area. The study demonstrated that the integration of two measuring devices whose development began in the second decade of the 20th century, i.e., UAVs and USVs, enables accurate (even up to several centimeters) and reliable determination of the scale and variability of the phenomena occurring in the littoral zone.

  • Methodology for hospital design in architectural education
    • Rafał Janowicz
    2020 Full text World Transactions on Engineering and Technology Education

    The architecture of a hospital should be a response to strong user requirements. Recommendations on how to shape the environment of such facilities are highly complex, integrating guidelines from many fields of science. If contradictions between them exist, the designer is required to set priorities for spatial activities. This issue is particularly important during architectural education. The learning process should include projects with a high level of complexity, thus providing students with the opportunity to prepare works in planning medical facilities. These works should include consideration that medical architecture is a multifaceted task, both in theoretical and practical terms. In this case, the methodology of improvement is a helpful teaching tool. The intent in producing this article was to illustrate the possibility of using process analysis to approximate the performance of medical procedures in the teaching process and their impact on the design of hospital buildings as complex engineering facilities.

  • Methylation effect in e−— scattering on methyl-substituted ethylenes
    • Sylwia Stefanowska-Tur
    • Czesław Szmytkowski
    • Elżbieta Ptasińska-Denga
    • Paweł Możejko
    2020 Full text Journal of Physics : Conference Series

    Methylation effect has been observed and studied in electron-scattering from selected hydrocarbon molecules. In measured total cross section (TCS) functions we have noticed energy shifts and changes in the intensity of observed structures.

  • Metoda lokalizowania sensorów IoT przy użyciu mobilnej stacji bazowej
    • Jacek Stefański
    • Jarosław Sadowski
    2020 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    W artykule opisano innowacyjną metodę lokalizowania obiektów dla potrzeb Internetu rzeczy (IoT). Przedstawiono matematyczną analizę metody. Opisano również wyniki kompleksowych badań symulacyjnych efektywności pracy zaproponowanej metody dla wybranych parametrów radiowej sieci sensorowej.

  • Metodologia badania skrzyni biegów z wykorzystaniem układu hydraulicznego jako hamowni
    • Marcin Bąk
    • Piotr Patrosz
    2020 Full text Napędy i Sterowanie

    W artykule przedstawiono metodologię prowadzenia badań mechanicznej skrzyni biegów. Sposób prowadzenia pomiarów zaprezentowano na przykładzie badań wybranej przekładni. Przedstawiono i opisano różne konfiguracje stanowiska badawczego wykorzystującego układ hydrauliczny, który pełnił funkcję hamowni. Zawarto opis konstrukcji prototypowej przekładni będącej obiektem badań. Ponadto omówiono przykładowe charakterystyki uzyskane w ramach przeprowadzonych testów.

  • Metodyka systematycznego przeglądu literatury w zakresie konkursów o nagrody jakości opartych na modelach doskonałości
    • Anna Wendt
    2020

    Model doskonałości można zdefiniować jako zbiór zasad kompleksowej oceny organizacji , który często wykorzystywany jest jako podstawa konkursów jakości. Celem niniejszego referatu jest systematyczny przegląd literatury o tematyce konkursów jakości opartych na modelach doskonałości, szczególnie związanych z modelem EFQM – modelem europejskim. Podczas badań wykorzystano trzy bazy literaturowe dostępne na Politechnice Gdańskiej – Taylor&Francis, Web of Science oraz Scopus. Za pomocną powyższej metody zdiagnozowany został stan faktyczny związany z konkursami na świecie. Uzyskano informacje na temat: liczby publikacji o tej tematyce, rozpoznawalności modeli doskonałości na świecie oraz o możliwościach ich wykorzystania. Ukazano lukę badawczą związaną z konkursami o charakterze krajowym i regionalnym.

  • Microcrystalline Cellulose Management in the Production of Poly(ether-urethane)s- Structure, Morphology, and Thermal Characteristic
    • Paulina Kasprzyk
    • Kamila Błażek
    • Janusz Datta
    2020 FIBERS AND POLYMERS

    In response to the demand of polymer industry for reducing the use of synthetic chemicals, eco-friendly materials are investigated. In the presented study, bio-based poly(ether-urethane)s were prepared by using microcrystalline cellulose (MCC) and polyether polyol and 1,3-propanediol derived from corn sugar. A step towards sustainability was taken by incorporating bio-based compounds and cellulose, consequently, bio-waste are utilized in a smart way. The new materials were synthesized via prepolymer method, while the cellulose fibers were added after the reaction. Structural studies of biocomposites were realized by FTIR technique. The number of free and hydrogen-bonded carbonyl groups was determined based on the deconvolution of C=O band. Crystallinity was assessed on the basis of X-ray diffraction analysis. The influence of the MCC content on the thermo-mechanical, thermal and selected mechanical properties has been demonstrated. Results obtained by SEM method showed that the higher degree of reinforcement led to the formation of aggregates reflecting their poor dispersion in the polymer matrix. It may probably result from the relatively weaker interaction between MCC and PU matrix. On the other hand, it was found that the incorporation of fibers improved the thermo-mechanical and thermal properties of the prepared materials. This work provides an effective way of using bio-renewable chemicals in the polyurethane industry without using additional processing apparatus and chemical processes. The used method makes it possible to obtain materials with high bio-content and satisfactory thermal characteristic.