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Repozytorium publikacji
Politechniki Gdańskiej

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  • Lipidomika – strategie analityczne i zastosowania
    • Weronika Hewelt-Belka
    • Agata Kot-Wasik
    2020

    Bioanalityka, to interdyscyplinarna dziedzina wiedzy, która stanowi szybko rozwijający się obecnie dział chemii analitycznej. Bioanaliza zaczyna odgrywać kluczową rolę w szybko rozwijających się dziedzinach współczesnej bionauki w ramach genomiki, proteomiki, metabolomiki, lipidomiki i innych. Umiejętność doboru odpowiednich metod i narzędzi, w zależności od rodzaju podejmowanego problemu, jest niezwykle ważne i często decyduje o powodzeniu zarówno kolejnych etapów jak i całości badań. Duże zainteresowanie bioanalityką, w tym kształcenie na poziomie przedmiotów podstawowych i specjalnościowych, jak również funkcjonowanie specjalności „Bioanalityka” na wielu uczelniach, potrzeby laboratoriów klinicznych czy medycyny sądowej, czy kontroli jakości produktów spożywczych i żywności, skłoniły redaktorów naukowych do przygotowania niniejszej książki. Przedstawione w niej zagadnienia będą przydatne studentom i pracownikom naukowym, pracownikom laboratoriów badawczych również z pokrewnych dziedzin. Książka ta jest opracowaniem zbiorowym, w którym znakomici specjaliści z różnych ośrodków naukowych i badawczych w Polsce przedstawili – potencjał, aplikacje kliniczne i środowiskowe oraz perspektywy dalszego rozwoju bioanalityki.

  • Lipidy szkodliwe dla zdrowia
    • Izabela Sinkiewicz
    2020

    Lipidy są niezbędne w diecie człowieka.Są one źródłem energii, niezbędnych, nienasyconych kwasów tłuszczowych i cholesterolu. Jednakże przekroczenie ich spożycia w stosunku do zapotrzebowania, stanowi zagrożenie dla zdrowia.Znajomość i przestrzegania prawidłowych racji lipidów i ich rodzaju w żywieniu powinno zapewnić konsumentom profilaktykę metabolicznych chorób układu krążenia oraz zapobiec nowotworom i otyłości

  • Liquefaction of alder wood as the source of renewable and sustainable polyols for preparation of polyurethane resins
    • Kamila Gosz
    • Daria Kowalkowska-Zedler
    • Józef Haponiuk
    • Łukasz Piszczyk
    2020 WOOD SCIENCE AND TECHNOLOGY

    Liquefaction of wood-based biomass gives different polyol properties depending on the reagents used. In this article, alder wood sawdust was liquefied with glycerol and poly(ethylene glycol) solvents. Liquefaction reactions were carried out at temperatures of 120, 150 and 170 °C. The obtained bio-polyols were analyzed in order to establish the process efficiency, hydroxyl number, acid value, viscosity and structural characteristics using Fourier transform infrared (FTIR), carbon (13C) and proton (1H) NMR analyses. The results indicate that the optimal conditions for the liquefaction process are at 150 °C for 6 h. The results of the FTIR spectra analysis and the hydroxyl number in the range of 214–687 mg KOH/g showed that the obtained bio-polyols are a potential substitute for petrochemical polyols commonly used for the synthesis of polyurethane polymers. Polyurethane resins containing 90 wt% of bio-polyol were obtained by a one-step method using a hydraulic press. The material was pressed for 15 min (5 MPa) at 100 °C with an NCO/OH ratio in the range of 0.9–1.2. Dynamic mechanical thermal analysis (DMA) showed high cross-linking density and modulus of elasticity in a wide range of 62–1362 MPa.

  • Literature review of user needs, toward user requirements
    • Claudia Naves David Amorim
    • David Geisler-Moroder,
    • Thorbjörn Laike
    • Justyna Martyniuk-Pęczek
    • Barbara Szybińska-Matusiak
    • Wilfried Pohl
    • Natalia Sokół
    2020

    This report has been developed in the frame of the IEA SHC Task 61 Subtask A “User requirements”. The main objective was to rethink and reformulate user requirements to lighting (daylighting and electric lighting) in public buildings on the basis of a thorough literature study. The work is a joint effort of a number of scientists and represents collective knowledge in this topic. The concept of Lighting quality is the one, among many lighting concepts, which expresses the user perspective best. Lighting quality is the important goal of lighting designers and planners; however, it is difficult to define and to measure. The following definition of lighting quality has been used for many years: Lighting quality is a concept that allows excellent vision while providing high comfort. (Kruisselbrink, Dangol and Rosemann) (2018) In this recent paper, the authors try to find measures that could be directly used for describing the lighting quality: quantity, glare, spectral power distribution, distribution of light, directionality and dynamics. The overview also shows that the luminance distribution is a suitable way for at least getting useful information of the lighting quality. If spectral distribution is added to these measurements an even better description of the lighting quality is obtained. The above-mentioned definition of lighting quality focuses at humans, but it does not take into consideration aspects of light that have indirect and profound impact on human health and well-being. Those are the non-image forming aspects of light and some psychological aspects. In this report those additional aspects are included and structured in chapters as follows: 1. Perception of light 2. Visual Comfort 3. Psychological aspects of lighting (view out, perceived quality of space, privacy, etc.) 4. Non-image forming aspects of light (ipRGCs action spectrum, hormones, etc.) By using these four different basic aspects we have the possibility to define several criteria for lighting quality, both image-forming and non-image forming. We have also the possibility to compare between qualities of electric lighting and daylighting. During the last twenty years the knowledge about light and lighting has developed and at the same time the technological development has been immense. Today we are able to get much more electrical lighting with less energy than ever before, but is the light of good quality? We need to develop evaluation methods.

  • LNG TANK IN ŚWINOUJŚCIE: NONLINEAR ANALYSIS OF THE TANK DOME ELEMENTS BEHAVIOUR
    • Bartosz Sobczyk
    2020 Pełny tekst Polish Maritime Research

    In this paper, the dome of a tank in the Świnoujście LNG terminal is analysed. Some of the rafter ribs at the connection with hangers were not mounted during construction of the tank dome. Therefore, it has become necessary to estimate its response, which has been done with the aid of some computational models of the dome, that have been created in the finite element method environment. Different local models are studied, aiming to recreate possible outermost conditions of the tank dome response, i.e. with or without composite action between steel and concrete parts of the tank dome. Static calculations with material and geometric nonlinearities are carried out on the computational models, enabling the creation of a load capacity envelope of the rafter with or without ribs. The obtained results are then used to decide if repair works need to be done and whether the missing ribs should be welded.

  • Local and global response of sandwich beams made of GFRP facings and PET foam core in three point bending test
    • Łukasz Pyrzowski
    • Bartosz Sobczyk
    2020 Pełny tekst COMPOSITE STRUCTURES

    In the paper behaviour of laminated sandwich beams (FRP face sheet – PET foam core – FRP face sheet) subjected to three point bending is studied. The paper aim is to find practical descriptions enabling effective and accurate estimation of the elastic response, damage and failure of the beams, basing on experiments and static calculations. Therefore a number of tests are described, that were done on laminated coupons and foam specimens in order to choose appropriate material models and find their constants. Experimental results of three-point bending tests of sandwich beams with three types of PET cores are analysed to evaluate the chosen material laws. The beam responses are predicted in numerical static simulations. The equations of problem are solved by means of finite element method (FEM). In the end the experimental and FEM results are compared. They are similar in terms of both their quantity and quality.

  • Local buckling of composite channel columns
    • Czesław Szymczak
    • Marcin Kujawa
    2020 Pełny tekst CONTINUUM MECHANICS AND THERMODYNAMICS

    The investigation concerns local buckling of compressed flanges of axially compressed composite channel columns. Cooperation of the member flange and web is taken into account here. The buckling mode of the member flange is defined by rotation angle a flange about the line of its connection with the web. The channel column under investigation is made of unidirectional fibre-reinforced laminate. Two approaches to member orthotropic material modelling are performed: the homogenization with the aid of theory of mixture and periodicity cell or homogenization upon the Voigt–Reuss hypothesis. The fundamental differential equation of local buckling is derived with the aid of the stationary total potential energy principle. The critical buckling stress corresponding to a number of buckling half-waves is assumed to be a minimum eigenvalue of the equation. Some numerical examples dealing with columns are given here. The analytical results are compared with the finite element stability analysis carried out by means of ABAQUS software. The paper is focused on a close analytical solution of the critical buckling stress and the associated buckling mode while the web–flange cooperation is assumed.

  • Lokalizacja terminala ruchomego w korytarzu przy użyciu kabli promieniujących
    • Olga Błaszkiewicz
    • Jarosław Sadowski
    • Jacek Stefański
    2020 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    W referacie przedstawiono wyniki testów możliwości określania położenia terminala ruchomego wzdłuż korytarza na podstawie propagacji sygnałów w kablach promieniujących w dwóch kierunkach. Opisane zostało stanowisko pomiarowe oraz wyniki uzyskane przy różnych sposobach wytwarzania sygnałów pomiarowych w instalacji jedno- i dwuprzewodowej.

  • Long Distance Geographically Distributed InfiniBand Based Computing
    • Karol Niedzielewski
    • Marcin Semeniuk
    • Jarosław Skomiał
    • Jerzy Proficz
    • Piotr Sumionka
    • Bartosz Pliszka
    • Marek Michalewicz
    2020 Pełny tekst Supercomputing Frontiers and Innovations

    Collaboration between multiple computing centres, referred as federated computing is becom- ing important pillar of High Performance Computing (HPC) and will be one of its key components in the future. To test technical possibilities of future collaboration using 100 Gb optic fiber link (Connection was 900 km in length with 9 ms RTT time) we prepared two scenarios of operation. In the first one, Interdisciplinary Centre for Mathematical and Computational Modelling (ICM) in Warsaw and Centre of Informatics – Tricity Academic Supercomputer & networK (CI- TASK) in Gdan ́sk prepared a long distance geographically distributed computing cluster. System consisted of 14 nodes (10 nodes at ICM facility and 4 at TASK facility) connected using Infini- Band. Our tests demonstrate that it is possible to perform computationally intensive data analysis on systems of this class without substantial drop in performance for a certain type of workloads. Additionally, we show that it is feasible to use High Performance Parallex [1], high level abstrac- tion libraries for distributed computing, to develop software for such geographically distributed computing resources and maintain desired efficiency. In the second scenario, we prepared distributed simulation - postprocessing - visualization workflow using ADIOS2 [2] and two programming languages (C++ and python). In this test we prove capabilities of performing different parts of analysis in seperate sites.

  • Long-Period Gratings and Microcavity In-Line Mach Zehnder Interferometers as Highly Sensitive Optical Fiber Platforms for Bacteria Sensing
    • Tinko Eftimov
    • Monika Janik
    • Marcin Koba
    • Mateusz Śmietana
    • Predrag Mikulic
    • Wojtek J. Bock
    2020 Pełny tekst SENSORS

    Selected optical fiber sensors offer extraordinary sensitivity to changes in external refractive (RI), which make them promising for label-free biosensing. In this work the most sensitive ones, namely long-period gratings working at (DTP-LPG) and micro-cavity in-line Mach-Zehnder interferometers (µIMZI) are discussed for application in bacteria sensing. We describe their working principles and RI sensitivity when operating in water environments, which is as high as 20,000 nm/RIU (Refractive index unit) for DTP-LPGs and 27,000 nm/RIU for µIMZIs. Special attention is paid to the methods to enhance the sensitivity by etching and nano-coatings. While the DTP-LPGs offer a greater interaction length and sensitivity to changes taking place at their surface, the µIMZIs are best suited for investigations of sub-nanoliter and picoliter volumes. The capabilities of both the platforms for bacteria sensing are presented and compared for strains of Escherichia coli, lipopolysaccharide E. coli, outer membrane proteins of E. coli, and Staphylococcus aureus. While DTP-LPGs have been more explored for bacteria detection in 102–106 Colony Forming Unit (CFU)/mL for S. aureus and 103–109 CFU/mL for E. coli, the µIMZIs reached 102–108 CFU/mL for E. coli and have a potential for becoming picoliter bacteria sensors.

  • LONG-TERM RISK CLASS MIGRATIONS OF NON-BANKRUPT AND BANKRUPT ENTERPRISES
    • Tomasz Korol
    2020 Pełny tekst Journal of Business Economics and Management

    This paper investigates how the process of going bankrupt can be recognized much earlier by enterprises than by traditional forecasting models. The presented studies focus on the assessment of credit risk classes and on determination of the differences in risk class migrations between non-bankrupt enterprises and future insolvent firms. For this purpose, the author has developed a model of a Kohonen artificial neural network to determine six different classes of risk. Long-term analysis horizon of 15 years before the enterprises went bankrupt was conducted. This long forecasting horizon allows one to identify, visualize and compare the intensity and pattern of changes in risk classes during the 15-year trajectory of development between two separate groups of companies (150 bankrupt and 150 non-bankrupt firms). The effectiveness of the forecast of the developed model was compared to three popular statistical models that predict the financial failure of companies. These studies represent one of the first attempts in the literature to identify the long-term behavioral pattern differences between future “good” and “bad” enterprises from the perspective of risk class migrations.

  • Looking for the Optimal Location of an Eco-District within a Metropolitan Area: The Case of Tricity Metropolitan Area
    • Julia Kurek
    • Justyna Martyniuk-Pęczek
    2020 Pełny tekst Sustainability

    Compact housing structures located in city centers are considered to be the most energy and environmentally eective, mainly due to the access to services, transport networks and municipal infrastructures. There is the question of why so many of the acknowledged ecological housing complexes are located on the outskirts of cities or suburbs. Numerous cities decide to introduce strategies either to densify city centers, hoping to improve energy eciency. The Tricity metropolitan area is a special case undergoing dynamic transformation, and its development overlaps with the processes of both planned densification of the center as well as uncontrolled suburbanization. The goal of this study was to find the correlation between optimal location of an eco-district from the functional center of the Tricity metropolitan area, allowing for the most favorable energy and environmental parameters related both to the architectural and urban scale. The research was conducted in four dierent scenarios, concerning present and future development. In these scenarios, specific locations were examined, and the following were compared: total energy consumption, ecological footprint and CO2 lifecycle emissions. This study shows the possibility for suburban housing complexes with appropriate parameters in an edge city model to have the same or better results than complexes situated closer to the functional center of the city. This is mainly due to the building’s energy eciency, sustainable mobility, municipal infrastructure and relevant service access. The research proves the importance of implementing sustainable energy-saving and environmentally oriented activities at both an architectural and urban scale planning process.

  • Love your mistakes!—they help you adapt to change. How do knowledge, collaboration and learning cultures foster organizational intelligence?
    • Wioleta Kucharska
    • Denise A. D. Bedford
    2020 Pełny tekst JOURNAL OF ORGANIZATIONAL CHANGE MANAGEMENT

    Purpose: The study aims to determine how the acceptance of mistakes is related to adaptability to change in a broad organizational context. Therefore it explores how knowledge, collaboration, and learning culture (including “acceptance of mistakes”) might help organizations overcome their resistance to change. Methodology: The study uses two sample groups: students aged 18–24 (330 cases) and employees aged >24 (326 cases) who work in knowledge-driven organizations. Structural equation models were developed, assessed, and compared. Findings: The effect of the “learning climate” on “adaptability to change” mediated by “acceptance of mistakes” has been detected for young students aged 18-24; however this relationship is not significant for business employees aged >24. This result suggests that organizations, unlike universities, do not use mistakes as a tool to support learning that is to lead to change. Limitations: Both samples used in the study come from Poland. The business sample is in the majority represented by small and medium-sized enterprises. Therefore the presented findings may only apply to Poland. Practical implications: Acceptance of mistakes is vital for developing a learning culture. Mistakes help employees adapt to change. Hence, a learning culture that excludes the acceptance of mistakes is somehow artificial and may be unproductive. Paradoxically, the findings reveal that the fact that employee intelligence (adaptability to change) improves via mistakes does not mean that organizational intelligence will also increase. Thus, organizations that do not develop mechanisms of learning from mistakes lose the learning potential of their employees. Scientific implications: The study presents mistakes as a valuable resource that enables the adaptation and development of intelligence. Hence, this study brings to attention a promising research area of “learning from organizational mistakes” in the context of adaptability to change. The study should be replicated for large Polish companies, international companies, and other countries to get a total picture of this phenomenon. Moreover, the acceptance of mistakes would be a significant step to advance learning technologies. Novelty: This study proposes a constant learning culture scale that includes the “acceptance of mistakes” and “learning climate” dimensions. Further, it empirically proves the value of mistakes for adaptability to change.

  • Low energy differential elastic electron scattering from trichloromethane
    • B Diaz
    • G Tatreau
    • Borna Hlousek
    • Mateusz Zawadzki
    • Murtadha Khakoo
    2020 Pełny tekst Journal of Physics : Conference Series

    Experimental differential cross sections for low energy electron scattering from trichloromethane is measured utilizing a crossed electron-molecular beam experiment via the relative flow method, for the incident electron energies in the range of E = 0.5 eV-30 eV and the scattering angles in the range of θ = 10◦ − 130◦ .

  • Low energy elastic electron scattering from benzonitrile (C6H5CN)
    • G Tatreau
    • B Diaz
    • F Alharthi
    • Mateusz Zawadzki
    • Murtadha Khakoo
    2020 Pełny tekst Journal of Physics : Conference Series

    We present experimental differential elastic scattering cross sections (DCSs) for low energy electron scattering from benzonitrile along with integral and momentum-transfer cross sections that are determined from these DCSs. The measurements of DCSs are obtained using the relative flow method with helium as the standard gas, in a crossed electron-molecular gas beam arrangement. Our measurements are made at incident electron energies in the range of 1 − 30 eV and scattering angles in the range of (10◦ -130◦ ).

  • Low energy electron mass stopping power in H2
    • Mateusz Zawadzki
    • Murtadha Khakoo
    2020 Pełny tekst Journal of Physics : Conference Series

    We present experimental mass stopping powers of electrons in gaseous H2 obtained with a newly developed electron time-of-flight spectrometer, for the incident electron energy range of 10eV to 25eV. In our procedure the average energy loss is derived from our conversion of measured electron time-of-flight spectra into equivalent electron energy loss spectra so as to obtain the values of mass stopping power for electron scattering from H2.

  • Low energy inelastic electron scattering from carbon monoxide: I. excitation of the a3Π, a’3Σ+ and AΠ1 electronic states.
    • Mateusz Zawadzki
    • Morty Khakoo
    • Logan Voorneman
    • Luka Ratkovic
    • Zdenek Masin
    • Karel Houfek
    • Amar Dora
    • Russ Laher
    • Jonathan Tennyson
    2020 JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS

    Differential scattering cross sections for electron excitation of the three lowest excited electron states of carbon monoxide are obtained experimentally using low-energy electron energy-loss spectroscopy and theoretically using the R-matrix method. The incident electron energies range from near-threshold of 6.3 eV to 20 eV. Experimental scattering angles range from 20◦ to 120◦. The normalization of the experimental cross sections is made to available experimental elastic scattering data (Gibson et al 1996 J. Phys. B: At. Mol. Opt. Phys. 29 3197). The R-matrix calculations use three distinct close-coupling models and their results are compared to available experimental and theoretical cross sections. The overall comparison leads to significantly improved description of the excitation cross sections for this target.

  • 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst

    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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst

    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 Pełny tekst 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 Pełny tekst

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