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  • Functionalized Peptide Fibrils as a Scaffold for Active Substances in Wound Healing
    • Justyna Sawicka
    • Emilia Iłowska
    • Milena Deptuła
    • Paweł Sosnowski
    • Piotr Sass
    • Katarzyna Czerwiec
    • Klaudia Chmielewska
    • Aneta Szymańska
    • Zuzanna Pietralik-Molińska
    • Maciej Kozak
    • Paweł Sachadyn
    • Michał Pikuła
    • Sylwia Rodziewicz-Motowidło
    2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Technological developments in the field of biologically active peptide applications in medicine have increased the need for new methods for peptide delivery. The disadvantage of peptides as drugs is their low biological stability. Recently, great attention has been paid to self-assembling peptides that can form fibrils. Such a formulation makes bioactive peptides more resistant to enzymatic degradation and druggable. Peptide fibrils can be carriers for peptides with interesting biological activities. These features open up prospects for using the peptide fibrils as long-acting drugs and are a valid alternative to conventional peptidic therapies. In our study, we designed new peptide scaffolds that are a hybrid of three interconnected amino acid sequences and are: pro-regenerative, cleavable by neutrophilic elastase, and fibril-forming. We intended to obtain peptides that are stable in the wound environment and that, when applied, would release a biologically active sequence. Our studies showed that the designed hybrid peptides show a high tendency toward regular fibril formation and are able to release the pro-regenerative sequence. Cytotoxicity studies showed that all the designed peptides were safe, did not cause cytotoxic effects and revealed a pro-regenerative potential in human fibroblast and keratinocyte cell lines. In vivo experiments in a dorsal skin injury model in mice indicated that two tested peptides moderately promote tissue repair in their free form. Our research proves that peptide fibrils can be a druggable form and a scaffold for active peptides.

  • Fundamentals of classical and analytical mechanics
    • Krzysztof Lipiński
    2021

    The book is a monographic description of the present attempt to Newtonian and Lagrangian mechanics. But also, it could be found as a supplementary educational material useful for the graduate courses in mechanics taken by students majoring in mechanical engineering, physics or physical science. In the book you can find a brief introduction to concepts and principles of algebra of vectors; Kinematics of particles, mainly focused on non-Cartesian coordinates used in the description of the kinematics; Dynamics of particles; focused on Newton's laws of motion; motion of particles in one and in three dimensions; description of dynamics in inertial and non-inertial frames of reference; linear and angular momentums; work and energy principles; Kinematics and dynamics of spherical motion of rigid bodies; Euler’s angles; angular velocities and accelerations; conical surfaces of angular velocity vectors, steady precession, angular momentum of bodies that performs spherical motion, Euler’s equations of dynamics for bodies in spherical motion and their kinetic energy formulas; Kinematics and dynamics of general motion of rigid bodies; linear velocity and linear acceleration of points of the bodies; linear and angular momentum of rigid bodies; Newton-Euler’s dynamics equations; kinetic energy; Simplified theory of gyroscope; Mechanics express with the Lagrangian formalism; constraints and the constraint equations; main principles used in classifications of the constraints; generalized coordinates; virtual displacements and consequences of the virtual work principle; virtual velocities and the virtual power; generalized forces and the generalized equation of dynamics (d’Alembert’s principle); two types of Lagrange’s equations; some alternative principles of equilibrium.

  • Funkcjonowanie zespołów napędu hydraulicznego maszyn w niskich temperaturach otoczenia. Wyd.2
    • Ryszard Jasiński
    2021

    W pracy przedstawiono cztery warianty klasyfikacji rozruchów oziębionego napędu hydraulicznego. Pierwsza sytuacja dotyczy zagadnienia, w którym wszystkie zespoły układu napędowego wraz z olejem mają taką samą niską temperaturę podczas rozruchu. Pozostałe warianty odnoszą się do rozruchu w warunkach szoku termicznego wywołanych zasilaniem ciepłym czynnikiem roboczym oziębionych zespołów hydraulicznych. Rozruch zespołów w takich warunkach powoduje wstąpienie wiele niekorzystnych zjawisk. Jednym z nich są zmiany luzów między współpracującymi elementami zespołów hydraulicznych. W Laboratorium Hydrauliki Wydziału Mechanicznego Politechniki Gdańskiej, na stanowiskach w komorach niskich temperatur, przebadano: pompy zębate, tłoczkowe osiowe i promieniowe, siłowniki, silniki satelitowe i orbitalne, silnik tłokowy promieniowy oraz rozdzielacze proporcjonalne i klasyczne oraz serwozawór. Podczas badań zespołów rejestrowano wiele parametrów, na podstawie których uzyskano dane o przebiegach zmian temperatury elementów zespołów hydraulicznych, ciśnienia w kanałach zespołów, prędkości obrotnej, natężenia przepływu, momentu obrotowego w funkcji czasu. Przeprowadzono analizę zjawisk cieplnych typowych zespołów hydraulicznych, uruchamianych w warunkach szoku termicznego. Opracowano i opisano trzy metody do określenia obszarów parametrów prawidłowego lub nieprawidłowego działania zespołu hydraulicznego w warunkach szoku termicznego na podstawie analizy zmian luzów efektywnych między współpracującymi elementami. Tymi metodami są: eksperymentalna, analityczna i symulacji komputerowej. Wyznaczono wartości współczynników przejmowania ciepła w zależności od prędkości obrotowej lub natężenia przepływu. Wyznaczone współczynniki przejmowania ciepła posłużyły do przeprowadzenia symulacji komputerowych procesów nagrzewania zespołów hydraulicznych. Uzyskano rozkłady pól temperatury elementów zespołów hydraulicznych oraz przebiegi temperatury tych elementów potrzebne do wyznaczenia luzów między współpracującymi elementami zespołów. W pracy pokazano rezultaty symulacji komputerowej niektórych zespołów hydraulicznych: pompy wielotłoczkowej osiowej, silnika satelitowego i rozdzielacza proporcjonalnego. Wyniki z symulacji komputerowej porównano z wynikami eksperymentalnymi i uzyskano dużą zbieżność przebiegów temperatury elementów z badań eksperymentalnych i symulacji komputerowych. Przedstawiono kilka sposobów zapobiegania zanikowi efektywnego luzu.

  • Future Directions in Quantum Materials Synthesis
    • Tyrel McQueen
    • Tanya Berry
    • Juan Chamorro
    • Alireza Ghasemi
    • W. Adam Phelan
    • Elizabeth Pogue
    • Lucas Pressley
    • Mekhola Sinha
    • Veronica J. Stewart
    • Thao Tran
    • Hector Vivanco
    • Michał Winiarski
    2021

    The following sections are included: Introduction The Current State of the Art The Frontiers Exploring the Frontiers Conclusion

  • G2DC-PL+: a gridded 2 km daily climate dataset for the union of the Polish territory and the Vistula and Odra basins
    • Mikołaj Piniewski
    • Mateusz Szcześniak
    • Ignacy Kardel
    • Somsubhra Chattopadhyay
    • Tomasz Berezowski
    2021 Pełny tekst Earth System Science Data

    G2DC-PL+, a gridded 2 km daily climate dataset for the union of the Polish territory and the Vistula and Odra basins, is an update and extension of the CHASE-PL Forcing Data – Gridded Daily Precipitation and Temperature Dataset – 5 km (CPLFD-GDPT5). The latter was the first publicly available, high-resolution climate forcing dataset in Poland, used for a range of purposes including hydrological modelling and bias correction of climate projections. While the spatial coverage of the new dataset remained the same, it has undergone several major changes: (1) the time coverage was increased from 1951–2013 to 1951–2019; (2) its spatial resolution increased from 5 to 2 km; (3) the number of stations used for interpolation of temperature and precipitation approximately doubled; and (4) in addition to precipitation and temperature, the dataset consists of relative humidity and wind speed data. The main purpose for developing this product was the need for long-term areal climate data for earth-system modelling, and particularly hydrological modelling. Geostatistical methods (kriging) were used for interpolation of the studied climate variables. The kriging cross-validation revealed improved performance for precipitation compared to the original dataset expressed by the median of the root mean squared errors standardized by standard deviation of observations (0.59 vs. 0.79). Kriging errors were negatively correlated with station density only for the period 1951–1970. Values of the root mean squared error normalized to the standard deviation (RMSEsd) were equal to 0.52 and 0.4 for minimum and maximum temperature, respectively, suggesting a small to moderate improvement over the original dataset. Relative humidity and wind speed exhibited lower performance, with median RMSEsd equal to 0.82 and 0.87, respectively. The dataset is openly available from the 4TU Centre for Research Data at https://doi.org/10.4121/uuid:a3bed3b8-e22a-4b68-8d75-7b87109c9feb (Piniewski et al., 2020).

  • Galerkin formulations of isogeometric shell analysis: Alleviating locking with Greville quadratures and higher-order elements
    • Z. Zou
    • T.j.r. Hughes
    • M.a. Scott
    • Roger Sauer
    • E.j. Savitha
    2021 COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING

    We propose new quadrature schemes that asymptotically require only four in-plane points for Reissner–Mindlin shell elements and nine in-plane points for Kirchhoff–Love shell elements in B-spline and NURBS-based isogeometric shell analysis, independent of the polynomial degree p of the elements. The quadrature points are Greville abscissae associated with pth-order B-spline basis functions whose continuities depend on the specific Galerkin formulations, and the quadrature weights are calculated by solving a linear moment fitting problem in each parametric direction. The proposed shell element formulations are shown through numerical studies to be rank sufficient and to be free of spurious modes. The studies reveal comparable accuracy, in terms of both displacement and stress, compared with fully integrated spline-based shell elements, while at the same time reducing storage and computational cost associated with forming element stiffness and mass matrices and force vectors. The high accuracy with low computational cost makes the proposed quadratures along with higher-order spline bases, in particular polynomial orders, p = 5 and 6, good choices for alleviating membrane and shear locking in shells.

  • Gas mixtures recognition using an array of amperometric gas sensors with drifting or faulty sensors
    • Marta Dmitrzak
    • Paweł Kalinowski
    • Piotr Jasiński
    • Grzegorz Jasiński
    2021

    In this study, the possibility of using selected methods for diagnostics of performance of matrix composed with six amperometric electrochemical gas sensors is investigated. Measurements of sensor responses in selected concentrations of single toxic gases or gas mixtures were performed and were repeated over time to show sensor drift. Additionally, the studies on the sensors’ drift were performed. The drift has been recognized by Principal Component Analysis (PCA). The results show that the methods used in this work can be potentially applied to detect faulty or drifted sensor responses.

  • Gasification of Densified Biomass (DB) and Municipal Solid Wastes (MSW) Using HTA/SG Technology
    • Jan Stąsiek
    • Jacek Barański
    • Marcin Jewartowski
    • Jan Wajs
    2021 Pełny tekst Processes

    The necessity of economical and rational use of natural energy sources caused a rapid development of research on the possibilities of using non‐conventional energy resources. Taking the above into account, a new technological process of thermochemical conversion of biomass and communal waste, commonly known as High Temperature Air/Steam Gasification (HTA/SG) and Multi‐Staged Enthalpy Extraction Technology (HTAG‐MEET), was developed. In relation to traditional techniques of gasification or combustion of hydrocarbon fuels, the presented concept is characterized by higher thermal efficiency of the process, low emission of harmful compounds of carbon, sulfur, nitrogen, dioxins, furans and heavy metals. The use of a high‐temperature gasification factor causes an increased thermochemical decomposition of solid fuels, biomass and municipal waste into gaseous fuel (syngas), also with increased hydrogen content and Lower Calorific Value (LCV). In this study, the possibility of using a batch type reactor (countercurrent gasifier) was analyzed for gasification of biomass and municipal waste in terms of energy recovery and environmental protection. The proposed research topic was aimed at examining the possibility of using the thermal utilization of biomass and municipal waste through their high‐temperature decomposition in the presence of air, a mixture of air and steam. The main goals of the research were achieved during the implementation of several parallel stages of the schedule, which included, primarily: (a) study of the possibility of using thermal utilization of biomass and municipal waste through their high‐temperature gasification in the presence of air or a mixture of air and steam and, secondary (b) analytical and numerical modeling of high‐temperature gasification of biomass and municipal waste with the use of ANSYS CFD Fluent 6.3 software. Selected results of the experimental and numerical studies are properly presented. The higher temperature gasification concept shows the capability of this technology for maximizing the gaseous product yield in an up‐draft fixed bed gasifier. It was also observed that at a high temperature, steam addition contributed to the thermal conversion of biofuels to gas with higher production of hydrogen.

  • Gdyńskie perły czyli więcej niż modernizm
    • Patrycja Wójcik
    • Maria Sołtysik
    • Agata Abramowicz
    • Jacek Friedrich
    2021

    Monografia przedstawia różne tendencje stylowe w gdyńskie architekturze, zarówno w okresie międzywojennym jak i w latach powojennych

  • Gender and support Polish women at the beginning of their professional career in IT
    • Agnieszka Wałachowska
    2021

    The development of ICT should be understood not only as an increase in the number of users skilled in the use of new technologies, but also as an ever-increasing demand for qualified professionals capable of creating, administering, supporting, and servicing ICT systems. With regard to the continuous development of innovative technologies, there is a noticeably low share of women who actively create and co-create this sector, while at the same time providing an opportunity to increase efficiency in terms of adapting technologies to the expectations of a wider audience. In Poland, the share of women preparing to become ICT specialists by studying computer science is low, although constantly growing. The aim of the chapter is to notice the differences in the abilities and perception of their skills and professional ambitions between female and male IT students on the example of empirical data from the Gdańsk WSB University in the field of Computer Sciences and to indicate the initiative that helps to eliminate these differences. After outlining the problems underlying the dominance of men in the ICT sector, we show that even when women take up the challenge of studying IT, they still need support to overcome stereotypes. The IT for SHE initiative is described as an example of a program that offers such support. It is assessed in terms of diversity, flexibility, and an area directly related to strengthening the mentality. The conclusion of the work is that, because they have low self-esteem of their professional skills, talented IT students need help to enter the labor market and the diverse support programs are not indifferent in this role.

  • Generalization of Kramers-Krönig relations for evaluation of causality in power-law media
    • Jacek Gulgowski
    • Tomasz Stefański
    2021 Communications in Nonlinear Science and Numerical Simulation

    Classical Kramers-Krönig (K–K) relations connect real and imaginary parts of the frequency-domain response of a system. The K–K relations also hold between the logarithm of modulus and the argument of the response, e.g. between the attenuation and the phase shift of a solution to a wave-propagation problem. For square-integrable functions of frequency, the satisfaction of classical K–K relations implies causality in the time domain. On the other hand, when the K–K relations are checked for the logarithm of the system response, the function is not a square integrable one. Then one can employ classical K–K relations with subtractions, but their satisfaction for the logarithm of the system response does not imply causality of the original function. In this paper, the K–K relations are generalized towards functions which are not square-integrable, also allowing for causality evaluation when the logarithm of the system response is considered. That is, we propose generalization of the K–K relations with subtractions, whose validity for the logarithm of the system response and the satisfaction of additional assumptions imply causality of the originally considered function. The derived theory is then applied to electromagnetic media characterized by power-law frequency dispersion, i.e. the media which are described by fractional-order models (FOMs). In this case, the subtraction procedure generates functions which may be not square integrable, or even not locally integrable. However, we can rigorously analyse causality of the media described by FOM using the derived theory, as well as the parameter ranges for which such models are causal.

  • Generalized temperature dependence model for anammox process kinetics
    • Dominika Sobotka
    • Jun Zhai
    • Jacek Mąkinia
    2021 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    Temperature is a key operational factor influencing the anammox process kinetics. In particular, at temperatures below 15 °C, the specific anammox activity (SAA) considerably decreases. This study aimed to describe the temperature dependence of the anammox process kinetics in the temperature range from 10 to 55 °C, including the specific characteristics of“cold anammox”. The commonly used Arrhenius and extended and modifiedRatkowsky equations were examined. The Ratkowskyequationsyieldedastrong correlation (coefficient of determination, R2= 0.93–0.96) between the measured and predicted data over the analyzed temperature range(10–55 °C). However, these equations could not correctly reflect the anammox temperature dependence at temperatures below 15 °C (R2= 0.36–0.48). Therefore, a new generalized temperature model was proposed. The generalized temperature equation (GTE) considered the division of the analyzed temperature range into three temperature ranges: 10–15 °C, 15–35 °C and 35–55 °C. The ranges correspond to“cold anammox”,“(low)mesophilic anammox” and “thermophilic anammox”. The applied approach yielded a strong correlation between the measured and predicted SAA (R2= 0.97) over the temperature range from 10 to 55 °C and over the low-temperature range from 10 to 15 °C (R2= 0.99). Overall, the GTE could enhance the predictions of the temperature dependence of the anammox process kinetics. The GTE can help examine anammox-based bioaugmentation systems operating at both high temperatures (sidestream reactors) and low temperatures (mainstream reactors).

  • Generation-recombination and 1/f noise in carbon nanotube networks
    • A. Rehman
    • A. Krajewska
    • B. Stonio
    • K. Pavlov
    • G. Cywinski
    • D. Lioubtchenko
    • W. Knap
    • S. Rumyantsev
    • Janusz Smulko
    2021 Pełny tekst APPLIED PHYSICS LETTERS

    The low-frequency noise is of special interest for carbon nanotubes devices, which are building blocks for a variety of sensors, including radio frequency and terahertz detectors. We studied noise in as-fabricated and aged carbon nanotube networks (CNNs) field-effect transistors. Contrary to the majority of previous publications, as-fabricated devices demonstrated the superposition of generation-recombination (GR) and 1/f noise spectra at a low-frequency range. Although all the devices revealed identical current–voltage characteristics, GR noise was different for different transistors. This effect is explained by the different properties and concentrations of trap levels responsible for the noise. Unexpectedly, exposure of these devices to the atmosphere reduced both the resistance and GR noise due to nanotube’s p-doping by adsorbed water molecules from the ambient atmosphere. The presence of the generation recombination noise and its dependences on the environment provides the basis for selective gas sensing based on the noise measurements. Our study reveals the noise properties of CNNs that need to be considered when developing carbon nanotubes-based selective gas sensors.

  • Generowanie tekstu z użyciem sieci typu Transformer
    • Julian Szymański
    • Michał Wilk
    • Radosław Baziak
    2021

    Opisano działanie wybranych modeli uczenia maszynowego znajdujących zastosowanie w przetwarzaniu języka naturalnego w szczególności wy- korzystywanych do generowania tekstu. Przedstawiono również model BERT i jego różne wersje, a także praktyczne wykorzystanie modeli typu Transformer. Przedstawiono ich działanie w aplikacji zmieniającej nastrój tekstu w sposób sekwencyjny.

  • Genetic Background and Antibiotic Resistance Profiles of K. pneumoniae NDM-1 Strains Isolated from UTI, ABU, and the GI Tract, from One Hospital in Poland, in Relation to Strains Nationally and Worldwide
    • Magdalena Wysocka
    • Roxana Zamudio
    • Marco R Oggioni
    • Justyna Gołębiewska
    • Marek Bronk
    • Beata Krawczyk
    2021 Pełny tekst Genes

    In recent years, there has been an observed increase in infections caused by carbapenem-resistant Klebsiella pneumonia (Kp) strains. The aim of this study was the phenotypic and genotypic analysis of eight K. pneumoniae NDM (Kp NDM) isolates, recovered in Poland during the years 2016 and 2018 from seven patients with urinary tract infections (UTIs), asymptomatic bacteriuria (ABU), or colonization of the gut. PCR melting profile genotyping indicated a close relationship between the strains derived from 2018, which were not related to the strain isolated in 2016. WGS results were analyzed in relation to international Kp isolates. Clonal and phylogenetic analyses were performed based on multilocus sequence typing (MLST) and single nucleotide polymorphisms (SNPs) of the core genome. The metallo-β-lactamase was assigned to the NDM-1 type and the sequence was identified as ST11. Eleven antimicrobial resistance genes were detected, mostly from plasmid contigs. Unprecedented profiles of plasmid replicons were described with the IncFII/pKPX-1 dominant replicon. In terms of the KL24 and O2v1 capsular antigen profiles, these isolates corresponded to Greek strains. Strains isolated from UTI, ABU, and colonization GI tract patients were not carrying environment-specific virulence genes. Based on the assessment of strain relationships at the genome level and their direction of evolution, the international character of the sublines was demonstrated, with a documented epidemic potential in Poland and Greece. In con-clusion, some groups of patients, e.g., renal transplant recipients or those with complicated UTIs, who are frequently hospitalized and undergoing antibiotic therapy, should be monitored not only for the risk of UTI, but also for colonization by Kp NDM strains.

  • Geo-Questionnaire for Environmental Planning: The Case of Ecosystem Services Delivered by Trees in Poland
    • Patrycja Przewoźna
    • Adam Inglot
    • Marcin Mielewczyk
    • Krzysztof Mączka
    • Piotr Matczak
    • Piotr Wężyk
    2021 Pełny tekst Data

    Studies on society and the environment interface are often based on simple questionnaires that do not allow for an in-depth analysis. Research conducted with geo-questionnaires is an increasingly common method. However, even if data collected via a geo-questionnaire are available, the shared databases provide limited information due to personal data protection. In the article, we present open databases that overcome those limitations. They are the result of the iTre-es project concerning public opinion on the benefits provided by trees and shrubs in four different research areas. The databases provide information on the location of trees that are valuable to the residents, the distances from the respondents’ residence place, their attitude toward tree removal, socio-demographic variables, attachment to the place of life, and environmental attitudes. The presentation of all these aspects was possible thanks to the appropriate aggregation of the results. A method to anonymize the respondents is presented. We discuss the collected data and their possible areas of application.

  • Gigantic electro-chemo-mechanical properties of nanostructured praseodymium doped ceria
    • Victor Buratto Tinti
    • Ahsanul Kabir
    • Jin Kyu Han
    • Sebastian Molin
    • Vincenzo Esposito
    2021 NANOSCALE

    Some oxygen defective fluorites are non-Newnham electrostrictors, i.e., the electromechanical response does not depend on their dielectric properties. Here, we show gigantic electrostriction in nanocrystalline 25 mol% praseodymium doped ceria (PCO) bulk ceramics. The material was fabricated with a fieldassisted spark plasma sintering (SPS) process from high-purity nanoscale PCO powders (<20 nm). The SPS process consolidates the powders into a single-phase, highly dense material with a homogeneous microstructure and large grain boundary extension. Various thermally and chemically stable ionic defects are incorporated into the nanostructure, leading to superior electrical conductivity. The material shows an electrostriction strain coefficient (M33) of ∼10−16 m2 V−2 at frequencies below 100 Hz at room temperature. Such performance is comparable and even superior to Newnham’s electrostrictors, such as ferroelectric ceramics and polymeric actuators. Comparative analysis with polycrystals suggests that nanostructured PCO possesses electromechanically active nanodomains of Pr3+–VO pairs. Such results are unexpected and open novel insights on non-Newnham electrostrictors

  • Glass-ceramic sealants and steel interconnects: accelerated interfacial stability and reactivity tests at high temperature
    • Agnieszka Drewniak
    • Damian Koszelow
    • Patryk Błaszczak
    • Karolina Górnicka
    • Kacper Jurak
    • Hassan Javed
    • Antonio Gianfranco Sabato
    • Piotr Jasiński
    • Sebastian Molin
    • Federico Smeacetto
    2021 Pełny tekst MATERIALS & DESIGN

    High-temperature reactions between glass-ceramic sealants and Fe-Cr alloy interconnects may lead to the formation of undesirable phases, and consequently degradation of solid oxide fuel/electrolyser devices. In this work, three different glass-ceramic sealants (Na-containing, Ba-containing, Sr-containing compositions) and Fe22Cr stainless steel powders (raw and pre-oxidised) are considered in order to test their chemical reactivity at 750°C and 850 °C for 500 h in static air. The novelty of this approach is related to the use of powder mixtures instead of studying the reactivity on planar interfaces, which allows a better evaluation the materials’ reactivity. Oxidation tests indicate that the Sr-containing glass-ceramic/steel couple is the least reactive among the aged samples. For the Ba-containing samples, the formation of an undesirable phase of BaCrO4 is observed by diffractometry and photoelectron spectroscopy analyses. The present research explores, for the first time, the effects of exposing the high surface area of the alloy powder and glass-ceramic sealant interface, assessed by oxidation testing and microstructural analysis. The results show that by using mixed powders with large interface surface areas, degradation of the materials can be observed after relatively short times, allowing accelerated screening of the reactivity of materials, and thus their further development.

  • Global EM-Driven Optimization of Multi-Band Antennas Using Knowledge-Based Inverse Response-Feature Surrogates
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2021 Pełny tekst KNOWLEDGE-BASED SYSTEMS

    Electromagnetic simulation tools have been playing an increasing role in the design of contemporary antenna structures. The employment of electromagnetic analysis ensures reliability of evaluating antenna characteristics but also incurs considerable computational expenses whenever massive simulations are involved (e.g., parametric optimization, uncertainty quantification). This high cost is the most serious bottleneck of simulation-driven design procedures, and may be troublesome even for local tuning of geometry parameters, let alone global optimization. On the one hand, globalized search is often necessary because the design problem might be multimodal (i.e., the objective function features multiple local optima) or a reasonably good initial design may not be available. On the other hand, the computational efficiency of popular algorithmic approaches, primarily, nature-inspired population-based algorithms, is generally poor. Combining metaheuristics procedures with surrogate modeling techniques and sequential sampling methods alleviates the problem to a certain extent but modeling of nonlinear antenna responses over broad frequency ranges is extremely challenging, and the aforementioned solutions are normally limited to rather simple structures described by a few parameters. This paper proposes a novel approach to global optimization of multi-band antennas. The major component of the presented framework is the knowledge-based inverse surrogate constructed at the level of response features (e.g., frequency and level locations of the antenna resonances). The surrogate facilitates decision-making process of inexpensive identification of the most promising regions of the parameter space, and a rendition of the good-quality initial design for further local tuning. Our methodology is validated using three examples of dual- and triple-band antennas. The average optimization cost is only 150 full-wave antenna analyzes while ensuring precise allocation of the antenna resonances at the target frequencies. This performance is demonstrated superior over both local optimizers and population-based metaheuristics.

  • Globalized parametric optimization of microwave components by means of response features and inverse metamodels
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2021 Pełny tekst Scientific Reports

    Simulation-based optimization of geometry parameters is an inherent and important stage of microwave design process. To ensure reliability, the optimization process is normally carried out using full-wave electromagnetic (EM) simulation tools, which entails significant computational overhead. This becomes a serious bottleneck especially if global search is required (e.g., design of miniaturized structures, dimension scaling over broad ranges of operating frequencies, multi-modal problems, etc.). In pursuit of mitigating the high-cost issue, this paper proposes a novel algorithmic approach to rapid EM-driven global optimization of microwave components. Our methodology incorporates a response feature technology and inverse regression metamodels to enable fast identification of the promising parameter space regions, as well as to yield a good quality initial design, which only needs to be tuned using local routines. The presented technique is illustrated using three microstrip circuits optimized under challenging scenarios, and demonstrated to exhibit global search capability while maintaining low computational cost of the optimization process of only about one hundred of EM simulations of the structure at hand on the average. The performance is shown to be superior in terms of efficacy over both local algorithms and nature-inspired global methods.

  • Godna praca – koncepcja, pomiar i praktyka w wymiarze rynkowym i organizacyjnym
    • Łukasz Sienkiewicz
    2021

    W opracowaniu przedstawiono koncepcję „godnej pracy”, podejmując próbę analizy definicyjnej tego złożonego pojęcia. Dokonano analizy istniejących podejść, wychodząc od prac Międzynarodowej Organizacji Pracy służących wzmacnianiu godnej pracy w wymiarze globalnym, a także działań podejmowanych na rzecz rozwoju koncepcji „jakości pracy” w wymiarze europejskim. Dokonano przeglądu metod pomiaru godnej pracy oraz pracy wysokiej jakości, w tym stosowanych w tym zakresie mierników i narzędzi pomiarowych. Wskazano również na determinanty godnej pracy w trzech wymiarach: rynkowym, organizacyjnym i indywidualnym. Dokonano przeglądu badań dotyczących godnej pracy przed i po wybuchu pandemii Covid-19.

  • Gossiping by energy-constrained mobile agents in tree networks
    • Jurek Czyzowicz
    • Dariusz Dereniowski
    • Robert Ostrowski
    • Wojciech Rytter
    2021 THEORETICAL COMPUTER SCIENCE

    Every node of an edge-weighted tree network contains a data packet. At some nodes are placed mobile agents, each one possessing an amount of energy (not necessarily the same for all agents). While walking along the network, the agents spend the energy proportionally to the distance traveled and collect copies of the data packets present at the visited network nodes. An agent visiting a node deposits there copies of all currently possessed data packets and collects a copy of every data packet present at this node. Two agents meeting at a node may exchange any amount of currently possessed energy. The gossiping problem asks whether it is possible to achieve that a copy of the original data packet of each node may reach every other node of the network. We prove that the gossiping problem can be solved in time for an n-node tree network T, where k is the number of agents. Moreover, we prove that in order to compute a gossiping strategy, it is enough to start with a minimum-cost convergecast that ends with all data packets and all remaining energy being present at some node of T, and then finish with a minimum-cost broadcast from this configuration. Thus, we obtain two structural properties of the gossiping problem. First, if a gossiping is feasible and r is the first node receiving all information, then there is one that is a concatenation of a convergecast to r and a broadcast from r. Secondly, it is sufficient to consider only optimal convergecast strategies. This is natural to expect but hard to prove, as locations of agents after a convergecast (moved in this stage) are essential. Hence, the convergecast has to be optimal with regards to both spent energy as well as the resulting configuration of agents, which matters in the next stage.

  • „Gra (5)” (Alphago vs Sedol)
    • Krzysztof Wróblewski
    2021

    To już trzydziesta, jubileuszowa edycja przedsięwzięcia organizowanego przez Stowarzyszenie „Wielkie Serce” na rzecz Specjalnego Ośrodka Szkolno-Wychowawczego nr 1 im. J. Matejki w Krakowie. Po raz kolejny, ze względu na pandemię, aukcja zostanie zrealizowana w formule internetowej – finał Aukcji odbędzie się 27 listopada, początek o godz. 16.00. Gospodynią wieczoru będzie Anna Dymna. Zanim jednak odbędzie się sama aukcja, od 13 do 26 listopada w Muzeum Inżynierii Miejskiej trwała wystawa przedaukcyjna. Jednocześnie 13 listopada, o godz. 12.00 za pośrednictwem portalu artinfo.pl rozpoczęła się aukcja internetowa. Przedsięwzięcie po raz kolejny wsparli wybitni twórcy. W tegoroczną jubileuszową edycję aukcji włączyło się blisko dwustu polskich artystów. Podczas aukcji będzie można znaleźć dzieła m.in. takich twórców, jak: Magdalena Abakanowicz, Zdzisław Beksiński, Jan Berdyszak, Rafał Bujnowski, Tadeusz Dominik, Stanisław Dróżdż, Edward Dwurnik, Ryszard Horowitz, Jan Młodożeniec, Jerzy Kałucki, Ewa Kuryluk, Tomasz Kołodziejczyk, The Krasnals, Jarosław Modzelewski, Jan Młodożeniec, Jerzy Nowosielski, Stanisław Rodziński, Franciszek Starowieyski, Wilhelm Sasnal, Marek Sobczyk, Natalia LL, Jan Tarasin, Jerzy Tchórzewski, Ewa Zawadzka. Aukcja to wyjątkowa okazja dla miłośników i kolekcjonerów polskiej sztuki współczesnej. Kolejny raz będzie można obcować z dziełami artystów, którzy tworzą kanon grafiki i malarstwa polskiego, a wybrane prace będą dostępne już od kilkuset złotych.

  • Gradient versus proper gradient homotopies
    • Piotr Bartłomiejczyk
    • Piotr Nowak-Przygodzki
    2021 Homology Homotopy and Applications

    We compare the sets of homotopy classes of gradient and proper gradient vector fields in the plane. Namely, we show that gradient and proper gradient homotopy classi cations are essentially different. We provide a complete description of the sets of homotopy classes of gradient maps from R^n to R^n and proper gradient maps from R^2 to R^2 with the Brouwer degree greater or equal to zero.

  • Grafo-mania, czyli rzecz o grafach i algorytmach. Prawie 300 lat teorii powstałej blisko Gdańska
    • Marek Kubale
    2021 Pismo PG

    W niniejszym numerze inaugurujemy nową kolumnę popularnonaukową w dziale Edukacja. Będzie ona zawierała szkice poświęcone grafom i algorytmom dyskretnym

  • Grafo-mania, czyli rzecz o grafach i algorytmach. Spłaszczanie grafów
    • Marek Kubale
    2021 Pismo PG

    W eseju poruszono problem rysowania grafów na płaszczyźnie.

  • Grafo-mania, czyli rzecz o grafach i algorytmach. Twierdzenie o czterech barwach
    • Marek Kubale
    2021 Pismo PG

    Przedstawiono istotę i historię twierdzenia o 4 barwach.

  • Grafy w Imperium Rzymskim
    • Joanna Raczek
    2021 Pełny tekst Pismo PG

    Teoria grafów znalazła zastosowanie w sieciach telekomunikacyjnych, transporcie, bioinformatyce, zarządzaniu i w wielu innych dziedzinach. Ale co ma ona wspólnego z Imperium Rzymskim?

  • Graph Representation Integrating Signals for Emotion Recognition and Analysis
    • Teresa Zawadzka
    • Tomasz Wierciński
    • Grzegorz Meller
    • Mateusz Rock
    • Robert Zwierzycki
    • Michał Wróbel
    2021 Pełny tekst SENSORS

    Data reusability is an important feature of current research, just in every field of science. Modern research in Affective Computing, often rely on datasets containing experiments-originated data such as biosignals, video clips, or images. Moreover, conducting experiments with a vast number of participants to build datasets for Affective Computing research is time-consuming and expensive. Therefore, it is extremely important to provide solutions allowing one to (re)use data from a variety of sources, which usually demands data integration. This paper presents the Graph Representation Integrating Signals for Emotion Recognition and Analysis (GRISERA) framework, which provides a persistent model for storing integrated signals and methods for its creation. To the best of our knowledge, this is the first approach in Affective Computing field that addresses the problem of integrating data from multiple experiments, storing it in a consistent way, and providing query patterns for data retrieval. The proposed framework is based on the standardized graph model, which is known to be highly suitable for signal processing purposes. The validation proved that data from the well-known AMIGOS dataset can be stored in the GRISERA framework and later retrieved for training deep learning models. Furthermore, the second case study proved that it is possible to integrate signals from multiple sources (AMIGOS, ASCERTAIN, and DEAP) into GRISERA and retrieve them for further statistical analysis.

  • Graphs hard-to-process for greedy algorithm MIN
    • Marcin Jurkiewicz
    • Krzysztof Pastuszak
    • Mateusz Szypulski
    2021

    We compare results of selected algorithms that approximate the independence number in terms of the quality of constructed solutions. Furthermore, we establish smallest hard- to-process graphs for the greedy algorithm MIN.

  • Green analytical chemistry as an integral part of sustainable education development
    • Justyna Płotka-Wasylka
    • Heba M. Mohamed
    • Aleksandra Kurowska-Susdorf
    • Rajkumar Dewani
    • Michel Y. Fares
    • Vasil Andruch
    2021 Pełny tekst Current Opinion in Green and Sustainable Chemistry

    Green chemistry is an important way of thinking in the field of chemistry and aims to conduct processes in accordance with the principles of sustainable development. It is the application of a wide range of principles that minimize the impact of both chemical processes and products on the environment. And what about analytical chemistry? Without a doubt, analytical chemistry plays an important role in the sustainable development of the planet. However, this only applies if analytical procedures are of high quality (sensitive, precise and accurate) and also in line with the principles of environmental sustainability. This essay presents a brief discussion of the evolution of green chemistry and its multidimensional impacts, including the “industry” of analytical chemistry as well as academic education and research. We emphasize the difference between the term “sustainability” and “greenness”. Therefore, at least basic information on sustainability in analytical chemistry is provided. We hope that our considerations will inspire analytical chemists and will contribute to the further development of both green analytical chemistry and sustainable analytical chemistry.

  • Green TPUs from Prepolymer Mixtures Designed by Controlling the Chemical Structure of Flexible Segments
    • Paulina Kasprzyk
    • Ewa Głowińska
    • Paulina Parcheta-Szwindowska
    • Kamila Rohde
    • Janusz Datta
    2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    This study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols—poly(trimethylene glycol)s—with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4?- diphenylmethane diisocyanates and the bio-based 1,4-butanodiol (used as a chain extender and used to control the [NCO]/[OH] molar ratio). The impacts of the structure of flexible segments, the amount of each type of prepolymer, and the [NCO]/[OH] molar ratio on the chemical structure and selected properties of the TPUs were verified. By regulating the number of flexible segments of a given type, different selected properties of TPU materials were obtained. Thermal analysis confirmed the high thermal stability of the prepared materials and revealed that TPUs based on a higher amount of prepolymer synthesized from PO3G2700 have a tendency for cold crystallization. An increase in the amount of PO3G1000 at the flexible segments caused an increase in the tensile strength and decrease in the elongation at break. Melt flow index results demonstrated that the increase in the amount of prepolymer based on PO3G1000 resulted in TPUs favorable in terms of machining.

  • Greencoin: a Pro­environmental Action-­Reward System
    • Kacper Radziszewski
    • Helena Anacka
    • Paweł Weichbroth
    2021 Pełny tekst

    The massive destruction of the natural environment is rapidly eroding the world’s capacity to provide food and water, threatening the security of billions of people. In order to facilitate green lifestyles – understood in terms of both pro-environmental behaviors and green self-image on the one hand, and to build sustainable local and global communities, on the other, we put forward an idea of a novel action-reward system based on an application solution, namely Greencoin. In this paper, the framework of the pilot system, underpinning its earnings and value, is introduced. The novelty of the Greencoin system is in introducing an application adjusted to the local needs, that is, based on gamification and aims at encouraging, facilitating and rewarding citizens who undertake pro-environmental actions. In this context, we have formulated and answered two research questions, namely: what practical pro-environmental activities an individual can practice and evidence, as well as what rewards can be offered to an individual for performing such activities in the Greencoin application. To explore these topics, we adopted the literature review (along with the content analysis) method as the methodology for the research. The results concern a broad and multifaceted review of the literature on individual pro-environmental behavior through multiple disciplinary and subject-matter lenses, outlining the corresponding system of rewarding its participants (citizens) with non-monetary and monetary benefits that are to be used in the Greencoin pilot. The study contributes to the topic of smart cities, in particular digital and mobile eco-innovations, resulting in significant progress toward the goal of sustainable development by promoting and facilitating a more efficient and responsible use of natural resources.

  • Greencoin: prototype of a mobile application facilitating and evidencing pro-environmental behavior of citizens
    • Kacper Radziszewski
    • Helena Anacka
    • Hanna Obracht-Prondzyńska
    • Dorota Tomczak
    • Kacper Wereszko
    • Paweł Weichbroth
    2021 Pełny tekst

    Among many global challenges, climate change is one of the biggest challenges of our times. While it is one of the most devastating problems humanity has ever faced, one question naturally arises: can individuals make a difference? We believe that everyone can contribute and make a difference to the community and lives of others. However, there is still a lack of effective strategies to promote and facilitate pro-environmental behavior of individuals. To fill this gap, in this paper, we introduce and discuss the Greencoin mobile application prototype. The app is built on existing intelligent data-driven technologies, including supervised and unsupervised learning techniques. Since its end-users will mostly concern the city dwellers, the project falls into the scope of the ongoing research in the area of smart city applications. Nevertheless, the application is still in the design phase, we believe it is a good starting point to spark discussion on its further directions of development, as well as to draw the attention of both national and international audiences to the issues raised.

  • Gronden en afbeeldsels der voornaamste gebouwen, Van alle die Philips Vingboons geordineert heeft
    • Anna Sobolewska
    2021

    Nota katalogowa zawiera informacje nt autora ksiązki, holenderskiego architekta Philipa Vingeboons (1607-1678) i stylu jego zmysłu architektonicznego w projektowaniu amsterdamskich kamienic.

  • Ground Tire Rubber Filled Flexible Polyurethane Foam—Effect of Waste Rubber Treatment on Composite Performance
    • Paulina Kosmela
    • Adam Olszewski
    • Łukasz Zedler
    • Paulina Burger
    • Adam Piasecki
    • Krzysztof Formela
    • Aleksander Hejna
    2021 Pełny tekst Materials

    The application range of flexible polyurethane (PU) foams is comprehensive because of their versatility and flexibility in adjusting structure and performance. In addition to the investigations associated with further broadening of their potential properties, researchers are looking for new raw materials, beneficially originated from renewable resources or recycling. A great example of such a material is ground tire rubber (GTR)—the product of the material recycling of post-consumer car tires. To fully exploit the benefits of this material, it should be modified to enhance the interfacial interactions between PU and GTR. In the presented work, GTR particles were thermo-mechanically modified with the addition of fresh and waste rapeseed oil in the reactive extrusion process. The introduction of modified GTR particles into a flexible PU matrix caused a beneficial 17–28% decrease in average cell diameters. Such an effect caused an even 5% drop in thermal conductivity coefficient values, enhancing thermal insulation performance. The application of waste oil resulted in the superior mechanical performance of composites compared to the fresh one and thermo-mechanical modification without oils. The compressive and tensile performance of composites filled with waste oil-modified GTR was almost the same as for the unfilled foam. Moreover, the introduction of ground tire rubber particles enhanced the thermal stability of neat polyurethane foam.

  • Group-9 Transition-Metal Suboxides Adopting the Filled-Ti2Ni Structure: A Class of Superconductors Exhibiting Exceptionally High Upper Critical Fields
    • KeYuan Ma
    • Robin Lefèvre
    • Karolina Górnicka
    • Harald O. Jeschke
    • Xiaofu Zhang
    • Zurab Guguchia
    • Tomasz Klimczuk
    • Fabian O. von Rohr
    2021 CHEMISTRY OF MATERIALS

    Ti2Ni and the related η-carbide structure are known to exhibit various intriguing physical properties. The Ti2Ni structure with the cubic space group Fd3̅m is surprisingly complex, consisting of a unit cell with 96 metal atoms. The related η-carbide compounds correspond to a filled version of the Ti2Ni structure. Here, we report on the structure and superconductivity in the η-carbide-type suboxides Ti4M2O with M = Co, Rh, and Ir. We have successfully synthesized all three compounds in the single-phase form. We found all three compounds to be type-II bulk superconductors with transition temperatures of Tc = 2.7, 2.8, and 5.4 K and with normalized specific heat jumps of ΔC/γTc = 1.65, 1.28, and 1.80 for Ti4Co2O, Ti4Rh2O, and Ti4Ir2O, respectively. We found that all three superconductors exhibit high upper critical fields. Particularly noteworthy in this regard is Ti4Ir2O with an upper critical field of μ0Hc2(0) = 16.06 T, which exceeds by far the weak-coupling Pauli limit─widely considered as the maximal upper critical field─of μ0HPauli = 9.86 T. The role of the void-filling light atom X has so far been uncertain for the overall physical properties of these materials. Herein, we have successfully grown single crystals of Ti2Co. In contrast to the metallic η-carbide-type suboxides Ti4M2O, we found that Ti2Co displays a semimetallic behavior down to 0.75 K. Below 0.75 K, we observe a broad decrease in the resistivity, which can most likely be attributed to an onset of a superconducting transition at lower temperatures. Hence, the octahedral void-filling oxygen plays a crucial role in the overall physical properties, even though its effect on the crystal structure is small. Our results indicate that the design of new superconductors by incorporation of electron–acceptor atoms may in the Ti2Ni-type structures and other materials with crystallographic void position be a promising future approach. The remarkably high upper critical fields, in this family of compounds, may furthermore spark significant future interest.

  • Grywalizacja zajęć akademickich na Politechnice Gdańskiej
    • Joanna Mytnik
    • Brygida Mielewska
    • Aneta Sobiechowska-Ziegert
    • Katarzyna Kubiszewska
    • Natalia Gietka
    2021 Pismo PG

    Jak wyglądają zgrywalizowane zajęcia akademickie na Politechnice Gdańskiej i co sądzą o nich studenci? Zaprezentowano cztery wybrane wdrożenia prototypów zrealizowane w roku akademickim 2020/2021.

  • GTR/NBR/Silica Composites Performance Properties as a Function of Curing System: Sulfur versus Peroxides
    • Łukasz Zedler
    • Xavier Colom
    • Javier Cañavate
    • Krzysztof Formela
    2021 Pełny tekst Materials

    In this work, conventional sulfur and two types of organic peroxides (dicumyl peroxide (DCP) and di-(2-tert-butyl-peroxyisopropyl)-benzene (BIB)) curing systems were used to investigate the possibility for tailoring of the performance properties of GTR/NBR blends reinforced with a variable content of highly dispersive silica (0–30 phr). The curing characteristics, static mechanical and acoustical properties, swelling behavior, thermal stability, and microstructure of the prepared composites were investigated. The results show that regardless of the curing system used, increasing the content of highly dispersive silica resulted in the improvement of the mechanical properties of the studied materials. It was observed that sulfur-based systems are the best choice in terms of cross-linking efficiency determined based on torque increment and cross-link density parameters. However, further analysis of the physico-mechanical properties indicated that the cross-linking efficiency does not match the performance of specimens, and the materials obtained using organic peroxides show higher tensile properties. This is due to the improved physical interactions between the GTR/NBR matrix and highly dispersive silica when using peroxide systems. It was confirmed using the analysis of the Wolff activity coefficient, indicating the enhanced synergy.

  • Gustav Oelsners Werk aus polnischer Perspektive. das Erbe der moderne in der polnischen Architektur und Stadtplannung
    • Gabriela Rembarz
    2021

    Die Leistungen des Architekten Gustav Oelsner sind ein Beispiel für das gemeinsame Erbe der Region, das gemeinsam betrachtet werden sollte – ohne eine de facto künstliche Aufteilung in die Aktivitäten deutscher und polnischer Künstler. Eine solche Herangehensweise ist notwendig bei der Analyse der Biographie nicht nur des Altonaer Architekten, sondern vieler anderer, die das Schicksal der Geschichte in die nationale Einteilung einordneten und damit das Wissen um ihre Leistungen auf recht hermetischen Forschungsgebieten schlossen. Oelsners Werk kann ein wertvoller Leitfaden sein, der sowohl die Besonderheiten der modernistischen Architektur der Zwischenkriegszeit in Deutschland als auch in Mittel- und Osteuropa vorstellt. Die Publikation beschreibt das Schicksal des modernistischen Erbes in Polen vor dem Hintergrund der politischen Bedingungen des 20. Jahrhunderts. Die Bezüge der Architekten zu zeitgenössischen Herausforderungen dieser Zeit machen die Biografien progressiver Stadtarchitekten der Zwischenkriegszeit zu einer äußerst aktuellen Inspiration angesichts der zeitgenössischen Herausforderungen, nicht nur in Polen.

  • GVC and wage dispersion. Firm-level evidence from employee-employer database
    • Dagmara Nikulin
    • Joanna Wolszczak-Derlacz
    • Aleksandra Parteka
    2021 Pełny tekst EQUILIBRIUM Quarterly Journal of Economics and Economic Policy

    Research background: Wage inequalities are still part of an interesting policy-oriented research area. Given the developments in international trade models (heterogeneity of firms) and increasing availability of micro-level data, more and more attention is paid to wage differences observed within and be-tween firms. Purpose of the article: The aim of the paper is to address the research gap concerning limited cross-country evidence on a nexus of wage inequality–global value chains (GVCs), analysed from the perspective of wage inequality components within and between firms. Methods: This paper uses a large employee–employer database derived from the European Structure of Earnings Survey (SES), combined with sector-level indicators of GVC involvement based on the World Input-Output Database (WIOD). As a result, a rich database covering more than 7.5 million observations is created. The regression-based decomposition modelling technique developed by Fiorio and Jenkins (2010) is used to identify the contributions of different factors to wage inequalities, focusing on the components within and between firms. Findings & value added: The analysis presented in this paper aimed to show the contribution of GVC involvement, among various other factors, to the observed inequality of wages. Due to the use of a rich database that merges employer and employee data, the effects materialised with respect to different types of wages could be analysed separately, in particular components between and within firms. The general conclusion from the regression-based decomposition in log wages is that GVCs contribute marginally to the observed wage inequality in the European sample analysed in this paper. Some differences confronting the components within and between firms (the latter dominates) are observed; there is also certain intra sample heterogeneity in the estimated results (e.g. due to sector type or country group), but the general result is robust.

  • Health System Efficiency in European Countries: Network Data Envelopment Analysis Approach
    • Justyna Kujawska
    2021 Pełny tekst European Research Studies Journal

    Purpose: The article's main aim is to investigate the effectiveness of health systems in European countries based on EUROSTAT data. A comparative analysis of the health systems' effectiveness in different countries is based on their improvement (reform), using the best practices approach. Design/Methodology/Approach: The network DEA model and a slack-based model (NDEA – SBM) are used. A non-oriented model is used. The research sample covers 30 countries (28 EU plus Norway and Island). The health system considers two factors: lifestyle (LF) and primary medical care resources (MC). Lifestyle factors included, alcohol consumption, smoking, and being overweight. The primary resources of medical care are medical personnel, hospital beds, and finances. The subjective assessment of health status and healthy life expectancy is taken as direct outputs. As an intermediate product (link), the expenditure on prevention is assumed as a percentage of GDP. Findings: Health systems in five countries are identified as fully efficient. These countries have also achieved total efficiency for both divisions, lifestyle factors and medical care. The average efficiency of health systems for all countries is low and amounts to 0.619, and the average efficiency for the LF division is 0.580, with huge variations between countries. In the MC division, the average efficiency for all countries is 0.72. However, the difference between countries is more minor. For inefficient countries, the projection of necessary changes to achieve total efficiency has been calculated. Practical Implications: The network DEA model allows a better understanding of the functioning of the complex health care system by analyzing the effectiveness of two separate areas (lifestyle and health care). The values of the forecasted variables are also determined, inputs, outputs, and the linking variable that may help determine priority actions in the field of improving the efficiency of health systems. Originality/value: This paper contributes to the literature by applying the network model to assess the effectiveness of health systems. It enables simultaneous research of various areas related to health. Few publications have attempted to use the network model in the area of health protection.

  • Heat exchange enhancement of jet impingement cooling with the novel humped-cone heat sink
    • Marcin Froissart
    • Paweł Ziółkowski
    • Waldemar Dudda
    • Janusz Badur
    2021 Pełny tekst Case Studies in Thermal Engineering

    Jet impingement cooling technology is applicable to control temperature of devices, where very high heat flux is generated within a small area. This paper is about the improvement of the jet impingement cooling efficiency by the heat sink geometry modification. Two reference cases were sourced from the literature – flat heat sink and modified one with cone in the jet stagnation region. Such a change improves cooling capability by more than 10%. Presented thermal fluid-solid interaction numerical results are focused to understand better the physics of that improvement and proposed the next step of shape optimization. Two geometrical parameters were investigated – cooling channel’s height and cone’s side wall deformation radius. That includes twenty radiuses for each of three heights. Together with two reference cases, sixty-two shapes were analysed. Such extensive parametrical study was possible thanks to the usage of 2D axisymmetric model, which very well matched to the referenced 3D analysis and experiment. It was concluded, that cone deformation impact varies with the cooling channel’s height. For the optimum geometrical configuration, 11% cooling capability improvement was concluded in comparison to the reference flat surface (8% due to the channel height’s reduction and 3% due to the cone’s deformation).

  • HEAVE MOTION OF A VERTICAL CYLINDER WITH HEAVE PLATES
    • Ewelina Ciba
    2021 Pełny tekst Polish Maritime Research

    The shape of a vertical cylinder resembles the classic form of a spar platform. Spar platforms are floating platforms that are successfully used in waters of great depths and have several advantages that mean they are readily used in the oil industry. Many of these advantages are also relevant to their application for offshore wind turbines, which is currently being considered. In the hydrodynamic analysis of spar platforms, the determination of their hydrodynamic coefficients plays an important role. They can be determined based on the free decay test. The study presents a method for determining the hydrodynamic coefficients of an object based on the free decay test. The results of free oscillation calculations with the help of numerical fluid mechanics tools are presented and compared with the results of the experiment and analytical solution. The application of determined coefficients and their significance for floating platforms are discussed. The influence of change in the form of an additional damping element on the behaviour of spar structures is shown.

  • Heavy metal accumulation and distribution in Phragmites australis seedlings tissues originating from natural and urban catchment
    • Nicole Nawrot
    • Ewa Wojciechowska
    • Karolina Matej-Łukowicz
    • Jolanta Walkusz-miotk
    • Ksenia Pazdro
    2021 Pełny tekst ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

    The retention of heavy metal (HM) was studied in root and rhizomes (BLG), stems (ST), and leaves (LF) of Phragmites australis (common reed) seedlings collected from different locations, differing in the scale of anthropogenic interference. The analysis includes the reference samples of sediments in uncontaminated lake Garczonki and contaminated roadside ditch in Cieplewo. The concentrations of Zn, Cu, Pb, Cd, Ni, and Cr were analyzed in plant tissues and sediments using the atomic absorption spectrometry and inductively coupled plasma mass spectrometry. The general assessment of sediments collected in the Garczonki lake showed a good environmental status; while in the roadside ditch in Cieplewo, the sediments were considerably polluted with HM. In the first stage of plant growth, all of the analyzed HMs are mainly inhibited by BLG system. The decreasing trend of elements was as follows: BLG > ST > LF. The organs followed different decreasing trends of HM concentration; the trend Zn > Cu > Ni > Cr > Pb > Cd was found in ST and LF for the Garczonki lake seedlings and for BLG and LF for the roadside ditch in Cieplewo seedlings. Zn showed the highest concentration, while Cd the lowest concentration in each of the examined organs. The bioaccumulation factor indicated the higher mobility of HM in seedlings in the Garczonki lake than in the roadside ditch in Cieplewo. The morphological studies suggest the good state and health of seedling from both sites; however, the reduction of root hair surface was observed for the roadside ditch seedlings. The anatomical studies present changes in the size of the nucleus and count of chloroplasts in LF. No reaction on HM contamination sediments in the seedlings from the roadside ditch in Cieplewo in the aerenchyma was noted. Potentially, both types of seedlings can be used to decontaminate environments rich in HM. However, the level of HM absorbed by seedlings (in the first stage of growth) should be considered due to the behavior in the target phytoremediation site.

  • Helium-assisted, solvent-free electro-activation of 3D printed conductive carbon-polylactide electrodes
    • Maciej Jerzy Głowacki
    • Mateusz Cieślik
    • Mirosław Sawczak
    • Adrian Koterwa
    • Iwona Kaczmarzyk
    • Rafał Jendrzejewski
    • Łukasz Szynkiewicz
    • Tadeusz Ossowski
    • Robert Bogdanowicz
    • Paweł Niedziałkowski
    • Jacek Ryl
    2021 APPLIED SURFACE SCIENCE

    Fused filament fabrication is one of the most rapidly developing 3D printing techniques, with numerous applications, including in the field of applied electrochemistry. Here, the utilisation of conductive carbon black polylactic acid (CB-PLA) for 3D printouts is the most promising. To use CB-PLA as an electrode material, an activation process must be performed, removing the polymer matrix and uncovering the electrically conductive filler. We present a novel, alternative approach towards CB-PLA activation with Nd:YAG (λ = 1064 nm) laser ablation. We present and discuss the activation efficiency based on various laser source operating conditions, and the gas matrix. The XPS, contact angle, and Raman analyses were performed for evaluation of the surface chemistry and to discuss the mechanism of the activation process. The ablation process carried out in an inert gas matrix (helium) delivers a relatively high electrochemically active surface area of the CB-PLA electrode, while the resultant charge transfer process is hindered when activated in the air plausibly due to the formation of thermally induced oxide layers. The electroanalytical performance of laser-treated CB-PLA in a He atmosphere was confirmed through caffeine detection, offering detection limits of 0.49 and 0.40 μM (S/N = 3) based on CV and DPV studies, respectively.

  • Hidden Champions of Poland
    • Grażyna Leśniak- Łebkowska
    • Magdalena Popowska
    • Małgorzata Godlewska
    • Mirosław Łukasiewicz
    2021 Pełny tekst

    Poland is a country with a strong entrepreneurial spirit. The hidden champions’ performance has been closely related to political and economic changes: the fall of communism in 1989 and the transition from a centrally planned economy to a market economy. This led to the emergence of small private businesses focused on the domestic market. The accession to the European Union in 2004 created new perspectives for the hidden champions’ growth after the opening of the international markets, financial, educational, and institutional support, legal regulations, and FDI inflow with new technologies. Liberal democracy enabled the hidden champions to emerge in almost all industries. The majority of them have been taken over by large international companies. This has enabled their high performance. In the Global Competitiveness Index, Poland moved from 57th position in 2011 to 37th in 2018. Polish hidden champions build their positions using strong partnerships with suppliers and customers. Their competitive position is weaker than that of leading Western companies due to Poland’s less developed business culture and the complexity of regulations increasing the transaction costs and business risks. Hidden champions go international with their products and services and are masters in securing their access to scarce resources. They offer strongly innovative products based on their own R&D and develop their brands and new distribution channels, such as e-commerce and digital marketing. Poland is one of the world’s leaders in the business services sector and provides a friendly environment to start-ups.

  • Hierarchical 2-step neural-based LEGO bricks detection and labeling
    • Tomasz Boiński
    2021 Pełny tekst

    LEGO bricks are extremely popular and allow the creation of almost any type of construction due to multiple shapes available. LEGO building requires however proper brick arrangement, usually done by shape. With over 3700 different LEGO parts this can be troublesome. In this paper, we propose a solution for object detection and annotation on images. The solution is designed as a part of an automated LEGO bricks arrangement. The proposed approach consists of 2 stages – object detection and labeling. The paper discusses different approaches and points out a final model. A 2-step, hierarchical model and the results are presented. An evaluation of the proposed solution is also given.

  • High load capacity spur gears with conchoidal path of contact
    • Pavlo Tkach
    • Pavlo Nosko
    • Oleksandr Bashta
    • Yurii Tsybrii
    • Oleksii Nosko
    2021 Pełny tekst Mechanics & Industry

    The present study is devoted to investigation of spur gears with a conchoidal path of contact and a convex-convex contact between teeth. The load capacity and energy efficiency were evaluated using both theoretical and experimental approaches. The theoretical analysis showed that the conchoidal gear pairs are 5–21% stronger in terms of contact stress and have similar energy efficiency as compared to the involute gear pairs of the same configuration. Experiments were conducted on a gear test rig. Its energy efficiency was determined by measuring the active power of the motor driving the pinion shaft and controlling the torque at the gear shaft. The load capacity of the tested gear pair was estimated by analysing changes in the energy efficiency. It was found that the conchoidal gear pair has more than 20% higher load capacity and slightly higher energy efficiency, which agrees well with the mentioned theoretical results. Thereby, the study concludes a substantially higher load capacity of the conchoidal gears compared to the traditional involute ones.

  • High Performance Control of AC Drives with Matlab/ Simulink
    • Abu-rub Haitham
    • Atif Iqbal
    • Jarosław Guziński
    2021

    Explore this indispensable update to a popular graduate text on electric drive techniques and the latest converters used in industry. The Second Edition of High Performance Control of AC Drives with Matlab®/Simulink delivers an updated and thorough overview of topics central to the understanding of AC motor drive systems. The book includes new material on medium voltage drives, covering state-of-the-art technologies and challenges in the industrial drive system, as well as their components, and control, current source inverter-based drives, PWM techniques for multilevel inverters, and low switching frequency modulation for voltage source inverters. This book covers three-phase and multiphase (more than three-phase) motor drives including their control and practical problems faced in the field (e.g., adding LC filters in the output of a feeding converter), are considered. The new edition contains links to Matlab®/Simulink models and PowerPoint slides ideal for teaching and understanding the material contained within the book. Readers will also benefit from the inclusion of: - A thorough introduction to high performance drives, including the challenges and requirements for electric drives and medium voltage industrial applications - An exploration of mathematical and simulation models of AC machines, including DC motors and squirrel cage induction motors - A treatment of pulse width modulation of power electronic DC-AC converter, including the classification of PWM schemes for voltage source and current source inverters - Examinations of harmonic injection PWM and field-oriented control of AC machines - Voltage source and current source inverter-fed drives and their control - Modelling and control of multiphase motor drive system Supported with a companion website hosting online resources. Perfect for senior undergraduate, MSc and PhD students in power electronics and electric drives, High Performance Control of AC Drives with Matlab®/Simulink will also earn a place in the libraries of researchers working in the field of AC motor drives and power electronics engineers in industry.