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Gdańsk University of Technology

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  • Rapid tolerance‐aware design of miniaturized microwave passives by means of confined‐domain surrogates
    • Anna Pietrenko-Dąbrowska
    2020 INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS

    The effects of uncertainties, primarily manufacturing tolerances but also incomplete information about operating conditions or material parameters, can be detrimental to the performance of microwave components. Quantification of such effects is essential to ensure a meaningful evaluation of the structure, in particular, its reliability under imperfect fabrication procedures. The improvement of the circuit robustness can be achieved by reducing sensitivity to geometry/material parameter deviations, which requires optimization of suitably chosen statistical performance metrics such as the yield. The prerequisite for the latter is statistical analysis. In the case of compact circuits, it is executed through full‐wave electromagnetic (EM) analysis. The fundamental difficulty, that is, the high CPU cost, can be alleviated by the employment of fast surrogate models, which is the method of choice for the majority of contemporary approaches. Despite its advantages, a practical challenge of surrogate‐assisted design is the initial computational overhead related to metamodel construction. As a workaround, this work proposes the employment of a recently introduced concept of constrained modelling, where the surrogate domain is confined only to contain the essential subsets of the parameter space. In the context of yield optimization, the domain needs to correspond to directions featuring maximum variability of the circuit responses (particularly the parts thereof that affect the yield value in the most significant way) with respect to its geometry parameters. The small volume of the domain spanned by such directions permits setting up an accurate model using a fraction of training data samples required by conventional methods. The proposed technique is demonstrated using a miniaturized microstrip rat‐race coupler with its yield optimized at the cost of just a few dozen of EM simulations of the circuit. EM‐based Monte Carlo simulations corroborate the reliability of the approach.

  • Raportowanie obrotu produktami leczniczymi w doskonaleniu przepływu informacji o stanach magazynowych aptek
    • Olga Mąka
    • Anna Zielińska
    • Grzegorz Zieliński
    2020 Problemy Jakości

    Celem opracowania jest identyfikacja roli raportowania obrotu produktami leczniczymi w aptekach. Zaprezentowano podstawowe założenia wymogu raportowania stanów magazynowych, w odniesieniu do poszczególnych grup interesariuszy, związanych z informacją o stanach magazynowych w aptece. Zidentyfikowano również korzyści dla poszczególnych grup interesariuszy wynikające z konieczności przygotowania tego typu raportów.

  • Raportowanie społeczne w sądach powszechnych
    • Sylwia Morawska
    • Przemysław Banasik
    2020

    Pomimo upływu 20 lat od pojawienia się pierwszych pionierskich badań nad raportowaniem społecznym w organizacjach publicznych stan wiedzy w tym obszarze jest wciąż na wczesnym etapie. Liczba obecnych badań, chociaż wykazuje tendencję wzrostową, jest nadal niewielka i są one lokalne. Niedobór prac teoretycznych z pewnością stanowi hamulec dla pełnego rozwoju potencjału tej dziedziny badań. Intencją autorów rozdziału jest opracowanie modelu raportowania społecznego w sądach powszechnych. Wykorzystano literaturę krajową i międzynarodową dotyczącą prezentowanej tematyki, a także dokonano analizy stron internetowych wszystkich sądów powszechnych w celu identyfikacji sposobów komunikowania działań prospołecznych na rzecz interesariuszy przez sąd. Badania wykazują, że sądy sporadycznie komunikują działania prospołeczne na rzecz swoich interesariuszy. Żaden z badanych sądów nie opublikował na stronie internetowej raportu społecznego.

  • Reactive extrusion of biodegradable aliphatic polyesters in the presence of free-radical-initiators: A review
    • Marta Przybysz-Romatowska
    • Józef Haponiuk
    • Krzysztof Formela
    2020 POLYMER DEGRADATION AND STABILITY

    Nowadays, growing attention is being paid to the environment and sustainability, what fully justified research works focused on modification of biodegradable polymers and their composites. In this field of research reactive extrusion seems to be the most promising approach, which fits well to sustainable development strategy. In In the present work, the in-situ modification of biodegradable aliphatic polyesters and the compatibilization of their blends by the action of free-radical initiators has been reviewed. The main concerns are the mechanisms of the free radicals induced modification of aliphatic polyesters and their blends. The cross-linked, branched or degraded structures of the formed polymers/blends were comprehensively characterized as function of modifier type and processing conditions. Moreover, the reactive processing and various types of irradiation in respect to the inter chain modification of polymers were presented. Main advantages and disadvantages related to reactive extrusion of biodegradable aliphatic polyesters and their blends in presence of free-radical-initiators were also pointed and discussed.

  • Reactive Processing and Functionalization of Ground Tire Rubber
    • Łukasz Zedler
    • Marta Przybysz-Romatowska
    • Aleksander Hejna
    • Xavier Colom
    • Javier Cañavate
    • Mohammad Saeb
    • Krzysztof Formela
    2020

    The dynamic development of the automotive industry resulted in a sig- nificant increase in rubber wastes, especially end-of-life tires, which are a serious threat to the natural environment and human health. This situation has enforced the industry and academic research groups to search new and cost-effective methods for recycling waste tires. In this field of research, reactive processing and functionaliza- tion seem to be a very promising approach to extend recycling and the ‘up-cycling’ of ground tire rubber. This chapter presents recent progress in the modification of waste rubber and valorization strategies with special attention on structure-properties relationships of the products obtained.

  • Reactive Sintering of Ground Tire Rubber (GTR) Modified by a Trans-Polyoctenamer Rubber and Curing Additives
    • Łukasz Zedler
    • Daria Kowalkowska-Zedler
    • Xavier Colom
    • Javier Cañavate
    • Mohammad Reza Saeb
    • Krzysztof Formela
    2020 Full text Polymers

    The proposed method of ground tire rubber (GTR) utilization involves the application of trans-polyoctenamer rubber (TOR), a commercially available waste rubber modifier. The idea was to investigate the influence of various curing additives (sulfur, N-cyclohexyl-2-benzothiazole sulfenamide (CBS), dibenzothiazole disulfide (MBTS) and di-(2-ethyl)hexylphosphorylpolysulfide (SDT)) on curing characteristics, physico-mechanical, thermal, acoustic properties as well as the morphology of modified GTR, in order to evaluate the possibility of reclaiming GTR and the co-cross-linking between applied components. The results showed that the presence of the modifier without the addition of curing additives hinders the physico-mechanical properties of revulcanized GTR. The addition of SDT, CBS, MBTS and sulfur change the melting kinetics of TOR, indicating partial degradation and/or co-cross-linking between components. In the studied conditions, the best mechanical properties were obtained by the samples cured with sulfur. The morphology analysis, combined with the physico-mechanical results, indicated that when the surface of the GTR is more developed, obtained by the addition of TOR, the properties of the GTR improve.

  • REALIZACJA USŁUGI DSR NA PRZYKŁADZIE DOMÓW JEDNORODZINNYCH
    • Paweł Bućko
    • Wiktoria Stahl
    2020 Full text Rynek Energii

    W artykule przedstawiono ideę usługi DSR, czyli reakcji strony popytowej, dla odbiorców rozproszonych. Polega ona na zmniejszeniu zapotrzebowania na energię elektryczną lub przesunięcia go w czasie. Wdrożenie usługi może w znaczny sposób wpłynąć na pracę systemu elektroenergetycznego – usługa DSR może wspomóc bilansowanie systemu elektroenergetycznego, a także pozytywnie oddziaływać na jego elastyczność, wydajność oraz stabilność. W artykule wykazano możliwy wpływ redukcji zapotrzebowania na energię elektryczną przez mieszkańców domów jednorodzinnych. Oszacowano spodziewany wpływ na obciążenie systemu skoordynowanego wykorzystania zagregowanych możliwości świadczenia usługi DSR przez większą grupę odbiorców indywidualnych w domach jednorodzinnych.

  • Realization, programming and controlling of the Stewart-Gough platform
    • Dawid Owoc
    • Krzysztof Ludwiczak
    • Robert Piotrowski
    2020 Full text Journal of Automation, Mobile Robotics and Intelligent Systems - JAMRIS

    This paper presents realizaon, programming, and controlling of a low cost Stewart-Gough plaorm (SGP) with rotary actuators. The realized SGP is applied in a ball & plate control system. Developed dedicated software consists of embedded and applicaon soware for both the SGP posioning system and the ball & plate control. system. A ball posion is being obtained using computer vision. The paper contains tests results for both an SGP posioning accuracy

  • Realizm kapitalistyczny. Czy nie ma alternatywy? / Mark Fisher; przełożył i posłowiem opatrzył Andrzej Karalus
    • Andrzej Karalus
    2020

    Praca rozważa, jak neoliberalna hegemonia instalując „ontologię biznesu” we wszystkich sferach rzeczywistości, formatuje niepostrzeżenie nasze pragnienia, aspiracje i nadzieje. Wbrew triumfalistycznej retoryce „efektywności” i „społecznej odpowiedzialności” realizm kapitalistyczny nie przestaje jednak generować systemowych zaburzeń, które w dłuższej perspektywie go destabilizują. Jest nie tylko przyczyną degradacji środowiska naturalnego i jednym z powodów, dla których mierzymy się z plagą depresji i neuroz, jest również odpowiedzialny za proliferację dużo mniej oczywistych i paradoksalnych zjawisk charakterystycznych dla post-fordowskiej fazy kapitalizmu: rozrostu biurokracji, „PRyzacji” rzeczywistości, sentymentalizacji polityki czy skasowania czasu. Fisher udanie łączy erudycję, zmysł obserwacji, krytyczną przenikliwość oraz wrażliwość na zjawiska i procesy kulturowe, nie uciekając przy okazji od pytań dotyczących kondycji współczesnej lewicy. Jak przełamać monopol realizmu kapitalistycznego i przezwyciężyć rodzące się tendencje autorytarne, nie popadając zarazem w paraliżujący tryb nostalgii i bezproduktywnej tęsknoty za państwem dobrobytu, dawno pogrzebanym światem powojennego konsensusu?

  • Real-Time Volatilomics: A Novel Approach for Analyzing Biological Samples
    • Tomasz Majchrzak
    • Wojciech Wojnowski
    • Małgorzata Rutkowska
    • Andrzej Wasik
    2020 Full text TRENDS IN PLANT SCIENCE

    The use of the ‘omics techniques in environmental research has become common-place. The most widely implemented of these include metabolomics, proteomics, genomics, and transcriptomics. In recent years, a similar approach has also been taken with the analysis of volatiles from biological samples, giving rise to the so-called ‘volatilomics’ in plant analysis. Developments in direct infusion mass spectrometry (DI-MS) techniques have made it possible to monitor the changes in the composition of volatile flux from parts of plants, single specimens, and entire ecosystems in real-time. The application of these techniques enables a unique insight into the dynamic metabolic processes that occur in plants. Here, we provide an overview of the use of DI-MS in real-time volatilomics research involving plants.

  • Recent advances in compatibilization strategies of wood-polymer composites by isocyanates
    • Aleksander Hejna
    • Marta Przybysz-Romatowska
    • Paulina Kosmela
    • Łukasz Zedler
    • Jerzy Korol
    • Krzysztof Formela
    2020 Full text WOOD SCIENCE AND TECHNOLOGY

    Wood-polymer composites technologies are gaining more and more attention in the scientific community, positively affecting the increase in their industrial applications, for example, automotive, building, 3D printing, etc. Many research works are focused on the improvement in matrix–lignocellulosic filler interactions to produce highly filled composites with satisfying performance properties. In this field of research, using isocyanates due to their versatile structure and functionality seems to be a very promising approach. This paper aims at reporting on recent advances in compatibilization strategies of wood-polymer composites by isocyanates. Particular attention is focused on the correlation between isocyanate structure, as well as modification conditions on the matrix–lignocellulosic filler interactions and their impact on the structure–property relationships of wood-polymer composites. Furthermore, limitations and future research trends related to applications of isocyanate to wood-polymer composites technologies are also discussed.

  • Recent advances in high-frequency modeling by means of domain confinement and nested kriging
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2020 Full text IEEE Access

    Development of modern high-frequency components and circuits is heavily based on full-wave electromagnetic (EM) simulation tools. Some phenomena, although important from the point of view of the system performance, e.g., EM cross-coupling effects, feed radiation in antenna arrays, substrate anisotropy, cannot be adequately accounted for using simpler means such as equivalent network representations. Consequently, the involvement of EM analysis, especially for tuning of geometry parameters, has become imperative in high-frequency electronics. Notwithstanding, excessive computational costs associated with massive full-wave simulations required by these procedures and even more by tasks such as uncertainty quantification or multi-criterial optimization, constitute a practical bottleneck. Repetitive evaluations of a structure can be facilitated by the use of fast replacement models (surrogates). Among available methods, approximation models are by far the most popular due to their flexibility and accessibility. Unfortunately, surrogate modeling of high-frequency structures is hindered by the curse of dimensionality and nonlinearity of system responses, primarily frequency characteristics. The recently proposed performance-driven techniques attempt to address this issue by appropriate confinement of the model domain to focus the modeling process only on the relevant part of the parameter space, i.e., containing the designs that are of high quality from the point of view the assumed performance figures. The nested kriging framework is perhaps the most advanced of these methods and allows for constructing reliable surrogates over broad ranges of the system parameters and operating conditions. This article summarizes the recent developments of the technique, including the basic formulation and several advancements aiming at the improvement of the surrogate predictive power or lowering the computational cost of training data acquisition. These include the incorporation of sensitivity data, as well as dimensionality reduction through principal component analysis. The problem of uniform data sampling in confined domains is also discussed. Our considerations are comprehensively illustrated using several examples of antennas and microwave circuits.

  • Recent Advances in Performance-Driven Surrogate Modeling of High-Frequency Structures
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2020 Full text INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS

    Design of high‐frequency structures, including microwave and antenna components, heavily relies on full‐wave electromagnetic (EM) simulation models. Their reliability comes at a price of a considerable computational cost. This may lead to practical issues whenever numerous EM analyses are to be executed, e.g., in the case of parametric optimization. The difficulties entailed by massive simulations may be mitigated by the use of fast surrogates, among which data‐driven models are the most popular ones due to their versatility and accessibility. Unfortunately, conventional modeling techniques are significantly affected by the curse of dimensionality. It is particularly restrictive in the case of high‐frequency components, typically exhibiting highly nonlinear characteristics. Recently, the concept of performance‐driven modeling has been proposed where the surrogate model setup is focused on a small subset of the parameter space, containing the designs that are optimal or nearly optimal with respect to the considered performance figures. Domain confinement allows for a dramatic reduction of the number of training data samples needed for rendering reliable surrogates valid over wide ranges of the system parameters. In this paper, we review some of the recent techniques employing these concepts, discuss their properties, and illustrate them using real‐world examples of antenna and microwave components.

  • Recent advances in traffic optimisation: systematic literature review of modern models, methods and algorithms
    • Aleksander Rydzewski
    • Paweł Czarnul
    2020 IET Intelligent Transport Systems

    Over the past few decades, the increasing number of vehicles and imperfect road traffic management have been sources of congestion in cities and reasons for deteriorating health of its inhabitants. With the help of computer simulations, transport engineers optimise and improve the capacity of city streets. However, with an enormous number of possible simulation types, it is difficult to grasp valuable, innovative solutions which are of the greatest value to city citizens. In this work, the authors expose various problems within this area having reviewed and analysed over 130 papers selected out of 1200 works in the field of urban simulations. The study describes the selection process of important papers and highlights characteristics of microsimulations, macrosimulations, computation optimisations and other approaches found in the literature which are especially useful and should be further built on in the future. They present and compare results provided in reviewed works in terms of throughput improvement, queue, waiting and travel time reduction, vehicle speed increase, speed‐ups as well as assumed simulation parameters. Finally, they focus on research gaps, such as a small number of works considering crisis simulations, few real‐world scale simulations as well as on software architectural changes and low‐level optimizations.

  • Recent progress in the development of steroid sulfatase inhibitors – examples of the novel and most promising compounds from the last decade
    • Mateusz Daśko
    • Sebastian Demkowicz
    • Karol Biernacki
    • Olga Ciupak
    • Witold Kozak
    • Maciej Masłyk
    • Janusz Rachoń
    2020 Full text JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY

    The purpose of this review article is to provide an overview of recent achievements in the synthesis of novel steroid sulfatase (STS) inhibitors. STS is a crucial enzyme in the biosynthesis of active hormones (including estrogens and androgens) and, therefore, represents an extremely attractive molecular target for the development of hormone-dependent cancer therapies. The inhibition of STS may effectively reduce the availability of active hormones for cancer cells, causing a positive therapeutic effect. Herein, we report examples of novel STS inhibitors based on steroidal and nonsteroidal cores that contain various functional groups (e.g., sulfamate and phosphorus moieties) and halogen atoms, which may potentially be used in therapies for hormone-dependent cancers. The presented work also includes examples of multitargeting agents with STS inhibitory activities. Furthermore, the fundamental discoveries in the development of the most promising drug candidates exhibiting STS inhibitory activities are highlighted.

  • Recent total cross section measurements in electron scattering from molecules
    • Czesław Szmytkowski
    • Paweł Możejko
    2020 Full text EUROPEAN PHYSICAL JOURNAL D

    The grand-total cross sections (TCSs) for electron scattering from a range of molecules, measured over the period 2009-2019 in various laboratories, with the use of different electron transmission systems, are reviewed. Where necessary, the presented TCS data are also compared to earlier results. Collection of investigated molecular targets (biomolecules, biofuels, molecules of technological application,hydrocarbons) reflects their current interest in biology, medicine, ecology and industry. Most of measurements covered the energy range from about 1 eV to some hundreds of eV, with a few exceptions extending those limits down to near thermal or up to almost high impact energies. The importance of reliable TCS data in the field of electron-scattering physics is emphasized. Problems encountered in TCS experiments are also specified

  • Reclaimed Rubber/Poly(ε‐caprolactone) Blends: Structure, Mechanical, and Thermal Properties
    • Aleksander Hejna
    • Łukasz Zedler
    • Marta Przybysz-Romatowska
    • Javier Cañavate
    • Xavier Colom
    • Krzysztof Formela
    2020 Full text Polymers

    The amount of elastomeric waste, especially from tires is constantly increasing on a global scale. The recycling of these residua should be considered a priority. Compounding the waste rubbers with other polymers can be an excellent alternative to reuse waste materials. This procedure requires solving the issue of the lack of compatibility between the waste rubber particles and other polymers. Simultaneously, there is a claim for introducing biodegradable plastics materials to reduce their environmental impact. In this work, reclaimed rubber/poly(ε‐caprolactone) (RR/PCL) blends are proposed to enhance the recycling and upcycling possibilities of waste rubbers. The results show that the addition of PCL to the RR allows obtaining blends with improved mechanical properties, good thermal stability, and enhanced interfacial compatibility between the used components. Structure and properties of the proposed RR/PCL have been studied by means of static and dynamic mechanical testing, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA)‐FTIR analysis.

  • Reconfiguring Minimum Dominating Sets in Trees
    • Magdalena Lemańska
    • Paweł Żyliński
    2020 Full text Journal of Graph Algorithms and Applications

    We provide tight bounds on the diameter of γ-graphs, which are reconfiguration graphs of the minimum dominating sets of a graph G. In particular, we prove that for any tree T of order n ≥ 3, the diameter of its γ-graph is at most n/2 in the single vertex replacement adjacency model, whereas in the slide adjacency model, it is at most 2(n − 1)/3. Our proof is constructive, leading to a simple linear-time algorithm for determining the optimal sequence of “moves” between two minimum dominating sets of a tree.

  • Recovery and Management of Postindustrial Spaces in the City on Selected Examples od European Implementations
    • Anna Stasiak
    2020 Full text Przestrzeń i Forma

    Undeveloped, neglected and then abandoned post-industrial areas often located in a short distance from city centers have become, on one hand a major problem for city stewards due to the formation of dead urban tissue disturbing the continuity and cohesion of urbanized areas, on the other hand are spaces with high potential for a good location. The article aims to formulate, from the architectural and urban perspective, an answer to the important question arising in this context: what activities are carried out to recover and properly manage post-industrial spaces?

  • Reduced-Cost Constrained Modeling of Microwave and Antenna Components: Recent Advances
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    • Leifur Leifsson
    2020

    Electromagnetic (EM) simulation models are ubiquitous in the design of microwave and antenna components. EM analysis is reliable but CPU intensive. In particular, multiple simulations entailed by parametric optimization or uncertainty quantification may considerably slow down the design processes. In order to address this problem, it is possible to employ fast metamodels. Here, the popular solution approaches are approximation surrogates, which are versatile and easily accessible. Notwithstanding, the major issue for conventional modeling methods is the curse of dimensionality. In the case of high-frequency components, an added difficulty are highly nonlinear outputs that need to be handled. A recently reported constrained modeling attempts to broaden the applicability of approximation surrogates by confining the surrogate model setup to a small subset of the parameter space. The said region contains the parameter vectors corresponding to high-quality designs w.r.t. the considered figures of interest, which allows for a dramatic reduction of the number of training samples needed to render reliable surrogates without formally restricting the parameter ranges. This paper reviews the recent techniques employing these concepts and provides real-world illustration examples of antenna and microwave structures.

  • Reducing common mode voltage and bearing currents in quasi - resonant DC - link inverter
    • Marek Turzyński
    • Piotr Chrzan
    2020 IEEE TRANSACTIONS ON POWER ELECTRONICS

    In the paper, a concept of separation of an inverter-fed induction motor drive from its mains supply by two transistor switches inserted in the dc-link circuit is reexamined based on the proposed parallel quasi-resonant dc-link inverter (PQRDCLI). The objective of the paper is to show an advantage of the proposed topology in limiting high frequency common mode voltage and bearing currents. In the laboratory setup, an induction machine was equipped with hybrid ceramic bearings and an insulated clutch to measure the shaft-to-frame bearing voltage and the shaft-grounding current. Experimental tests of the PQRDCLI confirm significant reduction of common mode voltage and shaft-to-frame bearing voltage at dc-link zero voltage notches. By controlling the output voltage slopes, the shaft-grounding brush current and the ground leakage current are also reduced. The efficiency measurement and evaluation of the proposed topology, as compared with a two-level hard switched inverter, reveal comparable efficiency of around 95% and indicate loss distributions in both inverters

  • Reduction of the Multipath Propagation Effect in a Hydroacoustic Channel Using Filtration in Cepstrum
    • Agnieszka Czapiewska
    • Andrzej Łuksza
    • Ryszard Studański
    • Andrzej Żak
    2020 Full text SENSORS

    During data transmission in a hydroacoustic channel, one of the problems is the multipath propagation effect, which leads to a decrease in the transmission parameters and sometimes completely prevents it. Therefore, we have attempted to develop a method, which is based on a recorded hydroacoustic signal, that allows us to recreate the original (generated) signal by eliminating the multipath effect. In our method, we use cepstral analysis to eliminate replicas of the generated signal. The method has been tested in simulation and during measurements in a real environment. Additionally, the influence of the method on data transmission in the hydroacoustic channel was tested. The obtained results confirmed the usefulness of the application of the developed method and improved the quality of data transmission by reducing the multipath propagation effect.

  • Refinement of the Hardening Soil model within the small strain range
    • Marcin Cudny
    • Andrzej Truty
    2020 Full text Acta Geotechnica

    The popularity of the elasto-plastic Hardening Soil (HS) model is based on simple parameter identification from standard testing and empirical formulas. The HS model is implemented in many commercial FE codes designed to analyse geotechnical problems. In its basic version, the stress–strain behaviour within the elastic range is subject to the hypoelastic power law, which assures the barotropy of the elastic stiffness. However, a proper modelling within the small strain range, i.e. strain-induced stiffness degradation and correct reproduction of the hysteretic behaviour, was one of the most important drawbacks in the HS formulation. The first small strain stiffness extension to the HS model was proposed by Benz (Small strain stiffness of soils and its numerical consequences, 2007), and the new model was called Hardening Soil Small (HSS). Despite the simple isotropic formulation, its applicability was proved in various numerical simulations in geotechnics. However, the HSS formulation exhibits a serious fault known in the literature as overshooting, i.e. uncontrolled reset of the loading memory after tiny unloading–reloading cycles. The authors’ main aim was to retain the set of material parameters for the HSS formulation and to propose a new small strain extension to the HS model without overshooting. The new proposal is based on the BRICK model which represents the concept of nested yield surfaces in strain space. The implementation aspects of the new HS-Brick model are described, and its performance is presented in some element tests and selected boundary value problems by comparisons with the HSS formulation.

  • Regulacja napięcia w sieci nN z rozproszonymi źródłami energii
    • Zbigniew Krzemiński
    2020 Full text Przegląd Elektrotechniczny

    Podłączanie rozproszonych źródeł energii do sieci energetycznych niskiego napięcia powoduje powstawanie problemów zmienności i niesymetrii napięcia, zwłaszcza w przypadku dużych odległości od transformatora zasilającego. W skrajnych przypadkach zachodzi konieczność redukcji mocy generowanej przez źródło podczas oddawaniu energii do sieci. Rozwiązaniem tego problemu jest zastosowanie energoelektronicznego regulatora napięcia składającego się z dwóch falowników, z których jeden służy do dodawania, za pomocą transformatora dodawczego, napięcia o regulowanej małej amplitudzie. Drugi falownik służy do dostarczania energii czynnej do układu regulacji oraz do korekty poboru mocy biernej w założonym zakresie. W referacie pokazano zastosowanie regulatora do stabilizacji napięcia sieci nN z generacją rozproszoną.

  • Regularity of weak solutions for aclass of elliptic PDEs in Orlicz-Sobolev spaces
    • Jakub Maksymiuk
    • Karol Wroński
    2020 Full text Topological Methods in Nonlinear Analysis

    We consider the elliptic partial differential equation in the divergence form $$-\div(\nabla G(\nabla u(x))) t + F_u (x, u(x)) = 0,$$ where $G$ is a convex, anisotropic function satisfying certain growth and ellipticity conditions We prove that weak solutions in $W^{1,G}$ are in fact of class $W^{2,2}_{loc}\cap W^{1,\infty}_{loc}$.

  • Regulation of the First Committed Step in Lipopolysaccharide Biosynthesis Catalyzed by LpxC Requires the Essential Protein LapC (YejM) and HslVU Protease
    • Daria Biernacka
    • Patrycja Gorzelak
    • Gracjana Klein-Raina
    • Satish Raina
    2020 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    We previously showed that lipopolysaccharide (LPS) assembly requires the essential LapB protein to regulate FtsH-mediated proteolysis of LpxC protein that catalyzes the first committed step in the LPS synthesis. To further understand the essential function of LapB and its role in LpxC turnover, multicopy suppressors of ΔlapB revealed that overproduction of HslV protease subunit prevents its lethality by proteolytic degradation of LpxC, providing the first alternative pathway of LpxC degradation. Isolation and characterization of an extragenic suppressor mutation that prevents lethality of ΔlapB by restoration of normal LPS synthesis identified a frame-shift mutation after 377 aa in the essential gene designated lapC, suggesting LapB and LapC act antagonistically. The same lapC gene was identified during selection for mutations that induce transcription from LPS defects-responsive rpoEP3 promoter, confer sensitivity to LpxC inhibitor CHIR090 and a temperature-sensitive phenotype. Suppressors of lapC mutants that restored growth at elevated temperatures mapped to lapA/lapB, lpxC and ftsH genes. Such suppressor mutations restored normal levels of LPS and prevented proteolysis of LpxC in lapC mutants. Interestingly, a lapC deletion could be constructed in strains either overproducing LpxC or in the absence of LapB, revealing that FtsH, LapB and LapC together regulate LPS synthesis by controlling LpxC amounts.

  • Reinforced Secure Gossiping Against DoS Attacks in Post-Disaster Scenarios
    • Christian Esposito
    • Zhongliang Zhao
    • Jacek Rak
    2020 Full text IEEE Access

    During and after a disaster, the perceived quality of communication networks often becomes remarkably degraded with an increased ratio of packet losses due to physical damages of the networking equipment, disturbance to the radio frequency signals, continuous reconfiguration of the routing tables, or sudden spikes of the network traffic, e.g., caused by the increased user activity in a post-disaster period. Several techniques have been introduced so far (mainly using data retransmission mechanisms) to tolerate such circumstances. Among them, gossiping has been shown to be efficient in the recovery from message losses. However, a conventional gossiping scheme may exhibit security problems, which can be exploited for further attacks (such as Denial of Service – DoS attack). For instance, the flooding method used by the gossiping can be used to forward the traffic towards many vulnerable nodes to drain their resources and compromise them. Typically, protection against DoS attacks is realized by using cryptographic primitives. However, their scalability limits and costs make them improper for emergency communications after a disaster. In this article, we introduce an approach based on reinforcement learning and game theory to protect the gossiping scheme from DoS attacks without incurring the costs of cryptographic primitives. In our method, nodes properly select which requests to satisfy, which in turn helps other nodes to avoid receiving manipulated gossip messages from malicious and colluded nodes. Additionally, our method operates without exploiting any cryptographic primitives, which prevents excessive energy waste that is undesired in post-disaster resilient networking. Simulation experiments performed in OMNeT++ confirmed the advantages of our approach over the reference schemes in terms of reliability, security, overhead, latency, and power efficiency.

  • Relacje międzyorganizacyjne w dobie Industry 4.0
    • Anna Horzela
    • Ewa Salecka
    • Edyta Gołąb-Andrzejak
    • Anna Tomaszuk
    2020 Full text

    Strukturę opracowania zbudowano w odniesieniu do zagadnienia relacji międzyorganizacyjnych. Omawianą kwestię osadzono w obecnych realiach Industry 4.0. Celem monografii jest omówienie roli Industry 4.0 w budowaniu i rozwoju relacji międzyorganizacyjnych oraz w kształtowaniu ich specyfiki. W pięciu rozdziałach przedstawiono aspekty „sieciowego” powiązania różnych podmiotów i jednostek na gruncie teorii zarządzania. Opracowanie otwiera nakreślenie założeń dotyczących koncepcji Industry 4.0. Kolejny rozdział poświęcono koncepcji kapitału relacyjnego przedsiębiorstw. W nawiązaniu do tematyki rozdziału 2 w kolejnym dokonano rozwinięcia koncepcji organizacji sieciowych. W kolejnych rozdziałach (4 i 5) zaprezentowano przykłady rozwoju relacji międzyorganizacyjnych: koncepcję zaangażowania klientów biznesowych (BCE) oraz koncepcję społecznej odpowiedzialności biznesu (CSR).

  • Relatively high-Seebeck thermoelectric cells containing ionic liquids supplemented by cobalt redox couple
    • Anita Sosnowska
    • Edith Laux
    • Herbert Keppner
    • Tomasz Puzyn
    • Maciej Bobrowski
    2020 Full text JOURNAL OF MOLECULAR LIQUIDS

    Meanwhile no general and reliable equation determining the Seebeck coefficient (S e ) and involving electro-chemical reaction effects was derived for solutions. We reported the database of 15,000 ionic liquids supplemented by three different redox couple systems: 0.01 mol/l Co 3+/2+ (bpy) 3 , 0.01 mol/l I 3-/3I- and 0.2 mol/l 3- /3I- , and the corresponding estimated Seebeck coefficients. We also reported methods for estimating Seebeck coefficients for those systems. First, Seebeck coefficients were measured for 17 ionic liquids and the 3 redox couples independently, and afterwards an analytical QSPR equation was derived after which the Seebeck coefficients for all possible combinations of cations and anions (resulting in 15,000 conceivable ionic liquid compounds) were derived. Following this, we analyzed the data and discovered tendencies and regularities. It was revealed that small, symmetrical and not branched cations and anions which contained less electronegative atoms, made the Seebeck increased. The highest S e = 2.3 mV/K, was observed for small ammonium and phosphonium cations with a triethyl-n-hexylboride anion. We also discovered that for thermo-electric applications cobalt-based redox couples are much better than the ones based on the iodine/iodide system.

  • Reliability of Corroded Stiffened Plate Subjected to Uniaxial Compressive Loading
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    2020 International Journal of Maritime Engineering

    The work is focused on the reliability of corroded stiffened plates subjected to compressive uniaxial load based on the progressive collapse approach as stipulated by the Common Structural Rules for Bulk Carriers and Oil Tankers, employing the limit state design. Two different cases have been investigated. In the first model, the corrosion degradation led to uniform thickness loss, whereas the mechanical properties were unchanged, as given in the Rules. In the second model, the plate thickness degradation was followed by mechanical properties reduction. The uncertainties related to the mechanical properties, thicknesses, and initial imperfections of the corroded stiffened plate were taken into account. Several initial design solutions of stiffened plates, as well as different severity levels of corrosion degradation were investigated. The results show that structural reliability significantly decreases with corrosion development, especially when in addition to the initial imperfections and corrosion plate thickness reduction, corroded plate surface roughness and the changes in the mechanical properties were considered. The uncertainties, their origins and confidence levels are discussed. It was found that non-linear time-dependent corrosion degradation accounting not only for the thickness reduction due to corrosion wastage but also the subsequent decrease of mechanical properties lead to a significant reduction in the reliability index. Additionally, it was defined that the reliability estimate is very sensitive to the uncertainties related to the initial thickness and the spread of corrosion degradation as a function of the time. Incorporating the probability of corrosion detection into the original reliability model introduces additional information about the validity of structural degradation that may lead to a higher beta reliability index estimate compared to the original model.

  • Reliability-Based Stability Analysis of a Baltic Cliff by the Combined Response Surface Method
    • Karol Winkelmann
    • Lesław Zabuski
    • Jarosław Przewłócki
    • Jarosław Górski
    2020 Full text Geotechnical and Geological Engineering

    A simple, straightforward computational procedure was proposed, incorporating the Response Surface Method (RSM) linked with the standard Monte Carlo (MC) simulation method and the Point Estimate Method (PEM). PEM samples make it possible to analyse the sensitivity of the cliff’s stability to variation in subsoil parameters and to reduce the number of random variables of the problem. The proposed methods were tested in two cases: a high failure probability (undrained state) and a moderate failure probability (drained case). The proposed method (CRSM) has been applied to probabilistic stability analysis of a Baltic cliff in Jastrzebia Gora, Poland.

  • Reliable OFDM Data Transmission with Pilot Tones and Error-Correction Coding in Shallow Underwater Acoustic Channel
    • Iwona Kochańska
    2020 Full text Applied Sciences-Basel

    The performance of Underwater Acoustic Communication (UAC) systems are strongly related to the specific propagation conditions of the underwater channel. Horizontal, shallow-water channels are characterised by extremely disadvantageous transmission properties, due to strong multipath propagation and refraction phenomena. The paper presents the results of communication tests performed during a shallow, inland-water experiment with the use of a laboratory model of a UAC system implementing the Orthogonal Frequency-Division Multiplexing (OFDM) technique. The physical layer of data transmission is partially configurable, enabling adaptation of the modulation and channel coding parameters to the specific propagation conditions. The communication tests were preceded by measurement of the UAC channel transmission properties. Based on the estimated transmission parameters, four configurations of OFDM modulation parameters were selected, and for each of them, communication tests were performed with the use of two Error-Correction Coding (ECC) techniques. In each case, the minimum coding rate was determined for which reliable data transmission with a Bit Error Rate (BER) of less than 10−4 is possible

  • Reliable Surrogate Modeling of Antenna Input Characteristics by Means of Domain Confinement and Principal Components
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2020 Full text Electronics

    A reliable design of contemporary antenna structures necessarily involves full-wave electromagnetic (EM) analysis which is the only tool capable of accounting, for example, for element coupling or the effects of connectors. As EM simulations tend to be CPU-intensive, surrogate modeling allows for relieving the computational overhead of design tasks that require numerous analyses, for example, parametric optimization or uncertainty quantification. Notwithstanding, conventional data-driven surrogates are not suitable for handling highly nonlinear antenna characteristics over multidimensional parameter spaces. This paper proposes a novel modeling approach that employs a recently introduced concept of domain confinement, as well as principal component analysis. In our approach, the modeling process is restricted to the region containing high-quality designs with respect to the performance figures of antennas under design, identified using a set of pre-optimized reference designs. The model domain is spanned by the selected principal components of the reference design set, which reduces both its volume and dimensionality. As a result, a reliable surrogate can be constructed over wide ranges of both operating conditions and antenna parameters, using small training datasets. Our technique is demonstrated using two antenna examples and is favorably compared to both conventional and constrained modeling approaches. Application case studies (antenna optimization) are also discussed.

  • Remote Sensing in Vessel Detection and Navigation
    • Henning Heiselberg
    • Andrzej Stateczny
    2020 Full text SENSORS

    The Special Issue (SI) “Remote Sensing in Vessel Detection and Navigation” highlighted a variety of topics related to remote sensing with navigational sensors. The sequence of articles included in this Special Issue is in line with the latest scientific trends. The latest developments in science, including artificial intelligence, were used. The 15 papers (from 23 submitted) were published.

  • REPORT Verification expertise of Detroit Diesel engines 16V149TI on the vessel ORP GEN. PUŁASKI
    • Zbigniew Korczewski
    • Jacek Rudnicki
    2020

    Verification expertise of propulsion engines for generating sets of the ORP GEN. PUŁASKI - type 16V149TI related to a complaint sent by the shipowner to Shiprepair Yard NAUTA S.A.

  • Research of electric drive systems with real time software configurable control
    • A. Anuchin
    • G.l. Demidova
    • Yu. Vagapov
    • Ryszard Strzelecki
    2020 Full text Science, Technology and Arts Research Journal

    Предмет исследования. Представлен учебно-лабораторный стенд для исследования систем управления элек- троприводами. Стенд используется для обучения студентов системам управления электроприводами и предна- значен для повышения эффективности усвоения материала. Метод. В основу предлагаемого решения положен метод взаимного нагружения электрических машин, питаемых от силовых преобразователей с общим звеном постоянного тока. Это позволяет использовать одну электрическую машину в качестве испытуемой, а другую — в качестве нагрузочной, и наоборот. Обеспечивается переток мощности от машины, работающей в генераторном режиме, к машине, функционирующей в двигательном. Подобное решение обеспечивает энергосберегающий режим работы — из сети потребляются только мощности для покрытия потерь в силовых преобразователях и машинном агрегате. Для изучения различных структур систем управления электродвигателей постоянного и переменного тока предложен способ организации программного обеспечения со свободно конфигурируемой структурой. Основные результаты. Приведено описание лабораторных стендов. Каждый стенд содержит двухмашинный агрегат, где электродвигатель получает питание от своего полупроводникового преобразователя, управляемого в реальном времени микроконтроллерной системой. Созданное программное обеспечение позво- ляет синтезировать исследуемую структуру управления с помощью настроек системы управления. Настройка осуществляется с использованием ряда свободно конфигурируемых управляющих элементов, которые ком- пилируются в алгоритм управления микроконтроллером. Безопасное выполнение эксперимента обеспечивает алгоритм управления, работающий во взаимодействии с основной программой, работающей в реальном времени. Таким образом, обеспечивается защита электродвигателей и силовых преобразователей. Наличие встроенных программных средств защиты позволило добиться надежной работы электроприводов мощностью 1,5 кВт и обе- спечить близкие к промышленным характеристики. Приведено подробное описание особенности лабораторного оборудования и его программного обеспечения для системы векторного управления асинхронным двигателем. Пример демонстрирует настройку систем управления, компиляцию исполняемого кода, процедуру проведения эксперимента и анализ результатов. Представленные результаты могут быть полезны научным и научно-педагогическим работникам, занимающимся подготовкой специалистов в области систем управления электроприводами.

  • RESEARCH ON ORGANIC COATINGS DESIGNED FOR UNDERWATER APPLICATIONS
    • Juliusz Orlikowski
    • Agata Jażdżewska
    • Kacper Jurak
    2020 Full text ARCHIVES OF METALLURGY AND MATERIALS

    Underwater steel structures require periodic maintenance. In the case of vessels, anti-corrosion works are carried out in the shipyard, where very good conditions for applying organic protective coatings can be provided. Very good surface preparation can be obtained by the use of abrasive blasting. The well-prepared metal surface is free from impurities (particularly inorganic salts). Suitable conditions for the application and renovation of coatings are also ensured (creating appropriate climatic conditions, drying the air, setting the appropriate air temperature). However, there are underwater constructions that cannot be transferred above the water level and, therefore, their conservation against corrosion can take place only under the surface of the water, which significantly hinders the execution of renovation works. In this work, protective coatings for underwater application were tested. The application of coatings on selected steel surfaces over and under the water was carried out. Physico-mechanical and electrochemical tests were carried out in order to assess the quality of the obtained corrosion protection. The possible difficulties faced when applying coatings in marine conditions were discussed.

  • Residue-Pole Methods for Variability Analysis of S-parameters of Microwave Devices with 3D FEM and Mesh Deformation
    • Mehrdad Rahimzadeh Rufuie
    • Adam Lamęcki
    • Piotr Sypek
    • Michał Mrozowski
    2020 Full text RADIOENGINEERING

    This paper presents a new approach for variability analysis of microwave devices with a high dimension of uncertain parameters. The proposed technique is based on modeling an approximation of system by its poles and residues using several modeling methods, including ordinary kriging, Adaptive Polynomial Chaos (APCE), and Support Vector Machine Regression (SVM). The computational cost is compared with the traditional Monte-Carlo method. To improve the efficiency, mesh deformation is applied within 3D FEM framework.

  • Resilience of 5G Mobile Communication Systems to Massive Disruptions
    • Tibor Cinkler
    • Akos Ladanyi
    • Jacek Rak
    • Christian Esposito
    • Gianluca Rizzo
    2020

    This chapter discusses vital techniques to enhance the resilience of 5G systems. It starts with dependability assessment of 5G networks. Next, it describes (a) the frequency fallback technique to improve availability and survivability of 5G services, (b) segment interleaving scheme to enhance communications resilience between base stations and the remaining part of the network and (c) multi-operator protection to address the resilience issues in a multi-operator scenario when one of the operators fails to deliver services, and the backup service can be provided to its users by another operator. Finally, it focuses on energy-aware techniques for dynamic management of base station configuration and of load distribution aimed at maximizing network survivability in case of disaster.

  • Respiratory signals derived from capacitive electrocardiogram on the smart chair
    • Adam Bujnowski
    • Mariusz Kaczmarek
    • Jerzy Wtorek
    • Kamil Osiński
    • Clemens Nieke
    • Edith Birrer
    2020 Full text

    Capacitive electrocardiogram (CECG) tends to deliver basic cardiac signals without need to use traditional glued electrodes. In the paper analysis of possibility if the ECG derived respiratory waveforms out of the CECG.

  • Response of cylindrical steel tank under stochastically generated non-uniform earthquake excitation
    • Daniel Burkacki
    • Robert Jankowski
    2020 Full text AIP Conference Proceedings

    Cylindrical steel tanks are very important structures in industrial facilities since their application is related to storing different types of products. Their safety and reliability have become a crucial issue because any damage may cause significant consequences, including ecological disaster. The most dangerous dynamic load acting on cylindrical steel tanks is related to earthquakes, especially that the seismic excitation may differ from place to place due to spatial seismic effects related to the propagation of seismic wave. Previous studies have confirmed that such non-uniform earthquake excitation may influence the response of large structures significantly. Stochastic methods of analysis have become an advantageous approach to simulate a spatiotemporal variation of ground motion field for the earthquake engineering problems. The aim of the present paper is to show the results of FEM numerical investigation focused on the response of a cylindrical steel tank under stochastically generated non-uniform earthquake excitation. The analysis has been conducted for the tank fully filled with petroleum. A method of conditional stochastic simulation of ground motions, using the spatiotemporal correlation function, has been applied to generate unknown acceleration time histories for different support locations, based on the earthquake record specified for one location. The results of the analysis clearly indicate that the consideration of spatial effects related to seismic wave propagation leads to the considerable changes in the response of cylindrical steel tank under earthquake excitation. It has also been shown that the application of the stochastic simulation with the spatiotemporal correlation function is an effective method which can be successfully used to generate earthquake records in different locations so as to consider the non-uniform ground motion excitation.

  • Results from a Genome-Wide Association Study (GWAS) in Mastocytosis Reveal New Gene Polymorphisms Associated with WHO Subgroups
    • Bogusław Nedoszytko
    • Marta Sobalska-Kwapis
    • Dominik Strapagiel
    • Magdalena Lange
    • Aleksandra Górska
    • Joanne N.G. Oude Elberink
    • Jasper van Doormaal
    • Marcin Słomka
    • Leszek Kalinowski
    • Marta Gruchała-Niedoszytko
    • Roman J. Nowicki
    • Peter Valent
    • Marek Niedoszytko
    2020 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Mastocytosis is rare disease in which genetic predisposition is not fully understood. The aim of this study was to analyze associations between mastocytosis and single nucleotide polymorphisms (SNPs) by a genome-wide association study (GWAS) approach. A total of 234 patients were enrolled in our study, including 141 with cutaneous mastocytosis (CM; 78 children and 63 adults) and 93 with systemic mastocytosis (SM, all adults). The control group consisted of 5606 healthy individuals. DNA samples from saliva or blood were genotyped for 551 945 variants using DNA microarrays. The prevalence of certain SNPs was found to vary substantially when comparing patients and healthy controls: rs10838094 of 5OR51Q1 was less frequently detected in CM and SM patients (OR = 0.2071, p = 2.21 × 10 − 29 ), rs80138802 in ABCA2 (OR = 5.739, p = 1.98 × 10 − 28 ) , and rs11845537 in OTX2-AS (rs11845537, OR = 6.587, p = 6.16 × 10 − 17 ) were more frequently detected in CM in children and adults. Additionally, we found that rs2279343 in CYP2B6 and rs7601511 in RPTN are less prevalent in CM compared to controls. We identified a number of hitherto unknown associations between certain SNPs and CM and / or SM. Whether these associations are clinically relevant concerning diagnosis, prognosis, or prevention remains to be determined in future studies.

  • Retrievable strain measuring system in screw displacement piles - readings and results interpretation problems
    • Mateusz Wiszniewski
    • Adam Krasiński
    2020

    Static load tests on foundation piles are generally carried out in order to determine load – displacement characteristic of the pile. For more detailed information, e.g. force distribution along the shaft, load transfer mechanism and characteristics of soil-structure interaction (unit resistance curves t-z, q-z) additional pile instrumentation is required. Most popular techniques focus on direct concrete strain measurements and their conversion into calculated loads. However, proper determination of that forces requires the exact value of pile material stiffness (EA). Due to difficulties in determination of that stiffness, additionally hampered by the practical lack of knowledge about the pile shafts real geometry, very often the interpretation results of instrumented load tests are inadequate and can be subjected to significant errors. This short paper presents general problems concerning the determination of reinforced concrete properties used to interpret the results of static load tests on instrumented piles. Characteristics of elastic modulus variability with strain and depth, shaft deformations and possible changes in cross section area are determined. Several case stories of instrumented pile load tests, geometry check, material laboratory testing are discussed in the paper and will be presented during the conference.

  • Re-use of the 20th century aviation infrastructure.=Adaptacje XX-wiecznej infrastruktury lotniskowej
    • Agnieszka Szuta
    2020 Full text Przestrzeń i Forma

    This article explores issues related to the adaptation of former aviation infrastructure. For research purposes, several adaptations of former airports and airplane hangars are selected and presented. Those examples show the importance of this infrastructure in today's urbanized landscape, as well as in history, and thus the social and cultural values it brings. The benefits of the redevelopment of former airport sites are also presented. W niniejszym artykule poruszone zostają kwestie związane z adaptacjami dawnej infrastruktury lotniskowej. W celach badawczych z grupy opuszczonych lotnisk wybrano i przeanalizowano kilka zaadaptowanych obiektów. Wyselekcjonowane przykłady pozwoliły na przedstawienie istotnej roli XX-wiecznej infrastruktury lotniskowej w dzisiejszym krajobrazie zurbanizowanym oraz jej wartości społeczne i kulturowe. Ukazano również zalety ponownego wykorzystania dawnych terenów lotni-czych i znajdujących się tam obiektów.

  • REVIEW OF CURRENT RESEARCH ON CHITOSAN AS A RAW MATERIAL IN THREE-DIMENSIONAL PRINTING TECHNOLOGY IN BIOMEDICAL APPLICATIONS
    • Szymon Mania
    • Adrianna Banach
    • Robert Tylingo
    2020 Full text Progress on Chemistry and Application of Chitin and Its Derivatives

    Three-dimensional (3D) biomaterial manufacturing strategies show an extraordinary driving force for the development of innovative solutions in the biomedical sector, including drug delivery systems, disease modelling and tissue and organ engineering. Due to its remarkable and promising biological and structural properties, chitosan has been widely studied for decades in several potential applications in the biomedical field. However, tools in the form of 3D printers have created new possibilities for the production of chitosan models, implants and scaffolds for cell cultures that are much more precise than existing ones. The article presents current achievements related to the possibility of using chitosan to create new materials for 3D printing in the form of chitosan bioinks, filaments, resins and powders dedicated for bioprinting, fused deposition modelling, stereolithography/digital light processing and selective laser sintering methods, respectively.

  • Review of the Application of Graphene-Based Coatings as Anticorrosion Layers
    • Karolina Ollik
    • Marek Lieder
    2020 Full text Coatings

    Due to the excellent properties of graphene, including flexibility that allows it to adjust to the curvature of the substrate surface, chemical inertness, and impermeability, graphene is used as an anticorrosion layer. In this review, we present the current state-of-the-art in the application of graphene in the field of protective coatings. This review provides detailed discussions about the protective properties of graphene coatings deposited by dierent methods, graphene-based organic coatings, the modification of graphene-based coatings, and the effects of graphene functionalization on the corrosion resistance of protective coatings.

  • Review on Current Status of Echinocandins Use
    • Martyna Mroczyńska
    • Anna Brillowska-Dąbrowska
    2020 Full text Antibiotics-Basel

    Fungal infections are rising all over the world every year. There are only five medical compound classes for treatment: triazoles, echinocandins, polyenes, flucytosine and allylamine. Currently, echinocandins are the most important compounds, because of their wide activity spectrum and much lower sides effects that may occur during therapy with other drugs. Echinocandins are secondary metabolites of fungi, which can inhibit the biosynthesis of β-(1,3)-D-glucan. These compounds have fungicidal and fungistatic activity depending on different genera of fungi, against which they are used. Echinocandin resistance is rare—the major cause of resistance is mutations in the gene encoding the β-(1,3)-D-glucan synthase enzyme. In this review of the literature we have summarized the characteristics of echinocandins, the mechanism of their antifungal activity with pharmacokinetics and pharmacodynamics, and the resistance issue.

  • Revisiting the estimation of cutting power with different energetic methods while sawing soft and hard woods on the circular sawing machine: a Central European case
    • Kazimierz Orłowski
    • Tomasz Ochrymiuk
    • Ludka Hlaskova
    • Daniel Chuchała
    • Zdenek Kopecky
    2020 Full text WOOD SCIENCE AND TECHNOLOGY

    In the classical approaches, used in Central Europe in practice, cutting forces and cutting power in sawing processes of timber are commonly computed by means of the specific cutting resistance kc. It needs to be highlighted that accessible sources in handbooks and the scientific literature do not provide any data about wood provenance, nor about cutting conditions, in which cutting resistance has been empirically determined. In the analyses of sawing processes, the use of a model with elements of fracture mechanics involved is an alternative way. In this work, predictions of the newly developed model (FRAC_MOD) for the circular sawing machine are presented. Thanks to this modern approach, it was possible to reveal the usefulness of the FRAC_MOD, using experimental results data on fracture toughness and shear yield stresses of both Polish pine (Pinus sylvestris L.) and Czech beech wood (Fagus sylvatica L.). The achieved results were compared to the forecasted values obtained with classical models (CLAS_PL and CLAS_CZ), which are commonly applied in Central European sawmills. The carried out analyses allowed us to discover undesired effects in the form of underestimation of cutting power when applying the CLAS_PL and CLAS_CZ models. For that reason, the FRAC_MOD cutting model could be suggested for the prediction of energetic effects in cases of dynamical analyses and even unsteady cases.

  • REVITALIZATION PROJECT OF SLUM TRANSFORMATION: A CASE STUDY HAY-AL TANAK,BEIRUT,LEBANON
    • Dorota Wojtowicz-Jankowska
    • Bahaa Boukalfouni
    2020 Full text Przestrzeń i Forma

    Slums are global phenomena that exist as a solution for those who couldn’t afford a house. This phenomenon is growing accompanying the rapid urbanization and the growth of the urban population, three-quarter of the world population anticipated to live in an urban environment by 2050 (Avis, 2016, p. 57). This paper reviews slum's evaluation of the revitalization project for one of the poorest slums in Beirut called Hay-Al Tanak. Improving both physical and social environments with a long term design intervention aiming to create a new sustainable housing development and up-grading the existing structure. Enhancing the responsibility for urgent action to support the present and secure the future generation

  • R/EXAMS JAKO WSPARCIE W WERYFIKACJI WIEDZY STUDENTÓW
    • Agnieszka Wałachowska
    2020 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Przydatność zasobów e-learningowych, takich jak testy i quizy online, można dostrzec w wielu sytuacjach: duża liczba studentów uczęszczających na dane zajęcia, utrwalanie, podsumowanie i weryfikacja wiedzy czy nauczanie na odległość. Celem artykułu jest zaprezentowanie pakietu R/exams dostępnego w programie statystycznym R jako wsparcia do tworzenia losowych i dynamicznych pytań oraz ich wykorzystania na platformie Moodle. Omówione zostaną różne typy pytań na przykładzie zadań ze statystyki.