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Gdańsk University of Technology

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  • Usability of mobile applications: a systematic literature study
    • Paweł Weichbroth
    2020 Full text IEEE Access

    Since the release of the first mobile devices, the usability of on-board applications has been the concern not only of software vendors but hardware manufacturers as well. The academia community later willingly joined the discussion on usability in terms of theory and empirical measurement, having experience and knowledge in desktop settings. At first sight, such a background should guarantee a solid foundation to conduct research on software usability in a new setting. However, a preliminary study on the subject matter revealed methodological disorder in contemporary literature. As a matter of fact, a need emerged to review existing usability definitions, attributes and measures to recognize all associated aspects. In order to fill this void, we conducted a systematic literature review on usability studies indexed by the Scopus database and devoted to mobile applications. The input volume covers 790 documents from 2001 to 2018. The data analysis shows that the ISO 9241–11 usability definition has been adopted in an unchanged form and popularized as the standard by the HCI community. Secondly, in total, 75 attributes were identified and analysed. The most frequent are efficiency (70%), satisfaction (66%) and effectiveness (58%), which directly originate from the above definition. Subsequently, the less frequent are learnability (45%), memorability (23%), cognitive load (19%) and errors (17%). The last two concern simplicity (13%) and ease of use (9%). Thirdly, in the evaluation of usability, controlled observation and surveys are two major research methods applied, while eye-tracking, thinking aloud and interview are hardly used and serve as complementary to collect additional data. Moreover, usability evaluations are often confused with user experience dimensions, covering not only application quality characteristics, but also user beliefs, emotions and preferences. All these results indicate the need for further research on the usability of mobile applications, aiming to establish a consensus in the theory and practice among all interested parties.

  • Use of pyridinium and pyrrolidinium ionic liquids for removal of toluene from gas streams
    • Iwona Cichowska-Kopczyńska
    • Robert Aranowski
    2020 Full text JOURNAL OF MOLECULAR LIQUIDS

    Separation of toluene from a toluene/N2 gas mixture using supported liquid membranes based on a series of pyridinium (1-butylpyridinium- bis(trifluoromethylsulfonyl)imide - [C4Py][Tf2N], 1-hexylpyridinium trifluoromethanesulfone [C6Py][Tf2N]) and pyrrolidinium (1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide - [C4Pyrr][Tf2N], 1-hexyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide - [C6Pyrr][Tf2N], 1-butyl-1-methylpyrrolidinium trifluoromethanesulfone - [C4Pyrr][TfO]) ionic liquids (ILs) was studied over a wide range of temperatures. The toluene permeability and selectivity of separation was investigated in terms of cation and anion type. It was found that both pyridinium and pyrrolidinium ILs show high toluene permeability, up to 2034 barrers, with satisfying separation selectivity. An analysis of two key factors that have an influence on this process, that is diffusion in a form of resistance resulting from the viscosity of membrane liquid and the solubility expressed by the partition coefficient, was made.

  • Using Fast Frequency Hopping Technique to Improve Reliability of Underwater Communication System
    • Jan Schmidt
    2020 Full text Applied Sciences-Basel

    Acoustic underwater communication systems designed to work reliably in shallow coastal waters must overcome major limitations such as multipath propagation and the Doppler effect. These restrictions are the reason for the complexity of receivers being built, whose task is to decode a symbol on the basis of the received signal. Additional complications are caused by the low propagation speed of the acoustic wave in the water and the relatively narrow bandwidth. Despite the continuous development of communication systems using coherent modulations, they are still not as reliable as is desirable for reliable data transmission applications. This article presents an acoustic underwater communication system that uses one of the varieties of the spread spectrum technique i.e., the fast frequency hopping technique (FFH). This technique takes advantage of binary frequency-shift keying (BFSK) with an incoherent detection method to ensure the implementation of a system whose main priority is reliable data transmission and secondary priority is the transmission rate. The compromised choice of parameters consisted of the selection between the narrow band of the hydroacoustic transducer and the maximum number of carrier frequency hops, which results from the need to take into account the effects of the Doppler effect. In turn, the number of hops and the symbol duration were selected adequately for the occurrence of multipath propagations of an acoustic wave. In addition, this article describes experimental communication tests carried out using a laboratory model of the FFH-BFSK data transmission system in the shallow water environment of Lake Wdzydze/Poland. The test results obtained for three channels of different lengths are discussed.

  • Using Moodle as a Solution to Interdisciplinary E-collaboration Issues
    • Ewa Kozłowska
    2020 Full text International Journal of Research in E-learning

    Rapid technological development in recent years has contributed to numerous changes in many areas of life, including education and communication. Establishing interdisciplinary collaboration brings many benefits, however, it is often associated with numerous problems and inconveniences, as well as the need of constant improvement, lifelong learning, professional development (CPD) and finding an effective way of information transferring. Living in a constant rush makes logical order of information transferring become a key aspect, as more and more operations are being done chaotically using multiple online tools. Although collaboration happens to be complicated even for colleagues specializing in different aspects of the same profession, establishing cooperation between specific groups of interdisciplinary specialists, such as engineers and physicians, has a significant impact on modern diagnostics and medical treatment development. Based on some selected case studies investigated at Gdańsk University of Technology and Medical University of Gdańsk, supported by an overview of the available education and collaboration tools, a solution based on the Moodle LMS platform has been proposed, implemented, and analyzed.

  • Using UAV Photogrammetry to Analyse Changes in the Coastal Zone Based on the Sopot Tombolo (Salient) Measurement Project
    • Pawel Burdziakowski
    • Cezary Specht
    • Pawel S. Dabrowski
    • Mariusz Specht
    • Oktawia Lewicka
    • Artur Makar
    2020 Full text SENSORS

    The main factors influencing the shape of the beach, shoreline and seabed include undulation, wind and coastal currents. These phenomena cause continuous and multidimensional changes in the shape of the seabed and the Earth’s surface, and when they occur in an area of intense human activity, they should be constantly monitored. In 2018 and 2019, several measurement campaigns took place in the littoral zone in Sopot, related to the intensive uplift of the seabed and beach caused by the tombolo phenomenon. In this research, a unique combination of bathymetric data obtained from an unmanned surface vessel, photogrammetric data obtained from unmanned aerial vehicles and ground laser scanning were used, along with geodetic data from precision measurements with receivers of global satellite navigation systems. This paper comprehensively presents photogrammetric measurements made from unmanned aerial vehicles during these campaigns. It describes in detail the problems in reconstruction within the water areas, analyses the accuracy of various photogrammetric measurement techniques, proposes a statistical method of data filtration and presents the changes that occurred within the studies area. The work ends with an interpretation of the causes of changes in the land part of the littoral zone and a summary of the obtained results.

  • Utility analysis and rating of energy storages in trolleybus power supply system
    • Mikołaj Bartłomiejczyk
    • Leszek Jarzębowicz
    2020 Full text

    The article discusses two energy storage applications in power supply system of public electrified transport. The first application aims at reducing the peak power of the traction substation. The second application increases effectiveness of using solar power plant to cover partial power demand of traction supply system. These two applications were discussed and analyzed based on trolleybus supply system in Gdynia, where most measurements were recorded.

  • Utilization of Gaseous Carbon Dioxide and Industrial Ca-rich Waste for Calcium Carbonate Precipitation: A Review
    • Natalia Czaplicka
    • Donata Konopacka-Łyskawa
    2020 Full text ENERGIES

    Technologies for the management of various types of waste and the production of useful products from them are currently widely studied. Both carbon dioxide and calcium-rich waste from various production processes are problematic wastes that can be used to produce calcium carbonate. Therefore, the purpose of this paper is to provide an overview about the state of the development of processes that use these two wastes to obtain a valuable CaCO3 powder. The paper reviews the current research on the use of post-distillation liquid from the Solvay process, steelmaking slag, concrete, cement, and gypsum waste as well as some others industrial Ca-rich waste streams in the calcium carbonate precipitation process via carbonation route. This work is an attempt to collect the available information on the possibility of influencing the characteristics of the obtained calcium carbonate. It also indicates the possible limitations and implementation problems of the proposed technologies.

  • Utilizing Genome-Wide mRNA Profiling to Identify the Cytotoxic Chemotherapeutic Mechanism of Triazoloacridone C-1305 as Direct Microtubule Stabilization
    • Jarosław Króliczewski,
    • Sylwia Bartoszewska
    • Magdalena Dudkowska
    • Dorota Janiszewska
    • Agnieszka Biernatowska
    • David Crossman
    • Karol Krzymiński
    • Małgorzata Wysocka
    • Anna Romanowska
    • Maciej Bagiński
    • Michal Markuszewski
    • Renata J. Ochocka
    • James F. Collawn
    • Aleksander F. Sikorski
    • Ewa Sikora
    • Rafal Bartoszewski
    2020 Full text Cancers

    Rational drug design and in vitro pharmacology profiling constitute the gold standard in drug development pipelines. Problems arise, however, because this process is often dicult due to limited information regarding the complete identification of a molecule’s biological activities. The increasing aordability of genome-wide next-generation technologies now provides an excellent opportunity to understand a compound’s diverse eects on gene regulation. Here, we used an unbiased approach in lung and colon cancer cell lines to identify the early transcriptomic signatures of C-1305 cytotoxicity that highlight the novel pathways responsible for its biological activity. Our results demonstrate that C-1305 promotes direct microtubule stabilization as a part of its mechanism of action that leads to apoptosis. Furthermore, we show that C-1305 promotes G2 cell cycle arrest by modulating gene expression. The results indicate that C-1305 is the first microtubule stabilizing agent that also is a topoisomerase II inhibitor. This study provides a novel approach and methodology for delineating the antitumor mechanisms of other putative anticancer drug candidates.

  • UV Light-Modulated Fluctuation-Enhanced Gas Sensing by Layers of Graphene Flakes/TiO2 Nanoparticles
    • Janusz Smulko
    • Tomasz Chludziński
    • Umut Çindemir
    • Claes-Goran Granqvist
    • He Wen
    2020 Full text Journal of Sensors

    We present experimental results of fluctuation-enhanced gas sensing by low-cost resistive sensors made of a mixture of graphene flakes and TiO2 nanoparticles. Both components are photocatalytic and activated by UV light. Two UV LEDs of different wavelengths (362 and 394 nm) were applied to modulate the gas sensing of the layers. Resistance noise was recorded at low frequencies, between 8 Hz and 10 kHz. The sensors’ response was observed in an ambient atmosphere of synthetic air and toxic NO2 at selected concentrations (5, 10, and 15 ppm). We observed that flicker noise changed its frequency dependence at different UV light wavelengths, thereby providing additional information about the ambient atmosphere. The power spectral density changed by a few times as a result of UV light irradiation. The sensors were operated at 60 and 120°C, and the effect of UV light on gas sensing was most apparent at low operating temperature. We conclude that UV light activates the gas-sensing layer and improves gas detection at low concentrations of NO2. This result is desirable for the detection of the components of gas mixtures, and the modulated sensor can replace an array of independent resistive sensors which would consume much more energy for heating. We also suggest that a more advanced technology for preparing the gas-sensing layer, by use of spin coating, will produce corresponding layers with thickness of about a few μm, which is about ten times less than that for the tested samples. The effects induced by the applied UV light, having a penetration depth of only a few μm, would then be amplified.

  • Uwarunkowania realizacji kontrapasa autobusowego w zmiennokierunkowej organizacji ruchu
    • Jacek Oskarbski
    • Karol Żarski
    2020 Full text Transport Miejski i Regionalny

    Polskie miasta wprowadzają rozwiązania mające na celu zachęcanie do korzystania z alternatywnych do podróży samochodem sposobów przemieszczania się, w tym transportem zbiorowym, co może przyczynić się do zmniejszenia zatłoczenia sieci ulicznej. Jednym z przykładów takich działań jest wprowadzenie dedykowanego zmiennokierunkowego pasa autobusowego na jednej z głównych arterii miasta Gdyni. Jest to pierwsze rozwiązanie w Polsce, które zostało uruchomione pod koniec ubiegłego roku. Głównym celem artykułu jest przedstawienie innowacyjnego rozwiązania oraz wskazanie jego wad i zalet oraz problemów, które pojawiły się na etapie wdrożenia. Przedstawiono ponadto metodę szacowania efektywności zmian w organizacji ruchu na podstawie badań terenowych i symulacyjnych, którą zastosowano podczas procesu planowania usprawnień.

  • Uwarunkowania użytkowania podłóg przemysłowych - Błędy projektowe
    • Maciej Niedostatkiewicz
    • Tomasz Majewski
    2020 Full text Inżynier Budownictwa

    Celem artykułu jest wskazanie błędów popełnianych najczęściej przy projektowaniu podłóg przemysłowych. Opisane błędy mają wpływ na powstanie usterek i uszkodzeń zarówno przed, jak i w okresie ich eksploatacji.

  • Uwarunkowania użytkowania podłóg przemysłowych . Błędy wykonawcze
    • Maciej Niedostatkiewicz
    • Tomasz Majewski
    2020 Full text Inżynier Budownictwa

    Celem artykułu jest wskazanie błędów najczęściej popełnianych w trakcie realizacji podłóg przemysłowych. Podobnie jak błędy projektowe maja one wpływ na powstawanie usterek i uszkodzeń zarówno przed, jak również w okresie eksploatacji podłóg przemysłowych. Artykuł ma charakter studium przypadku i został ograniczony do wybranej sytuacji z praktyki inżynierskiej

  • Uwierzytelnienie i autoryzacja w systemie STRADAR
    • Sylwester Kaczmarek
    • Marcin Narloch
    • Maciej Sac
    2020 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Przedstawiono rozwiązanie serwera uwierzytelnienia i autoryzacji (AA) w rozproszonym systemie STRADAR, udostępniającym funkcjonalności dla prowadzenia działań operacyjnych Morskiego Oddziału Straży Granicznej. System umożliwia prezentację na stanowisku wizualizacji zdarzeń (SWZ) bieżącej i archiwalnej sytuacji na mapie (AIS, radary), obrazu z kamer, zdjęć, notatek, rozmów telefonicznych oraz plików i wiadomości tekstowych (SMS) wymienianych przez funkcjonariuszy Straży Granicznej. Serwer AA udostępnia administratorowi systemu STRADAR funkcje związane z zarządzaniem kontami operatorów SWZ, w tym dodawanie, edycję i usuwanie kont operatorów, definiowanie uprawnień operatorów, a także wyświetlenie historii działań na poszczególnych kontach operatorów. W artykule opisano architekturę, interfejs użytkownika oraz testy oprogramowania serwera AA.

  • Użytkownicy sieci portów jachtowych obszaru South Coast Baltic w świetle badań
    • Marcin Forkiewicz
    2020

    South Coast Baltic jest obszarem turystyki żeglarskiej od Stralsundu w Niemczech, przez polskie wybrzeże Morza Bałtyckiego, do Kłajpedy na Litwie, obejmującym także duńską wyspę Bornholm oraz okolice rosyjskiego Kaliningradu. Głównym produktem turystycznym destynacji South Coast Baltic jest transgraniczna sieć portów jachtowych zlokalizowanych w ponad 130 miastach i miejscowościach, oferująca swoim klientom ok. dziesięć tysięcy miejsc postoju jachtów. Celem pracy jest identyfikacja form współpracy i organizacji portów jachtowych obszaru South Coast Baltic przez pryzmat wielokryterialnej charakterystyki ich użytkowników, tj. żeglarzy odbywających wielodniowe rejsy jachtami żaglowymi i motorowymi. Zdefiniowanej w ten sposób kategorii klientów, porty jachtowe oferują usługi związane postojem jachtów prywatnych i czarterowanych oraz pobytem członków załóg. Charakterystyka użytkowników sieci portów jachtowych obszaru South Coast Baltic stanowi pierwszy etap analizy strategicznej destynacji turystyki żeglarskiej południowego wybrzeża Morza Bałtyckiego. Dzięki kompleksowemu ujęciu problematyki klientów portów jachtowych zawiera mnóstwo inspirujących wskazówek do dalszych badań w wielu aspektach, np. morskiej turystyki żeglarskiej, zarządzania portami jachtowymi oraz rozwoju regionalnego miejscowości portowych i regionów nadmorskich. Ich celem powinno być opracowanie zintegrowanej strategii zarządzania obszarem South Coast Baltic z jego kluczowym transgranicznym produktem turystycznym – międzyorganizacyjną siecią portów jachtowych. Książka jest adresowana do wszystkich interesariuszy portów jachtowych południowego wybrzeża Morza Bałtyckiego.

  • Vacuum ultraviolet photoionization and ionic fragmentation of the isoxazole molecules
    • Tomasz Wąsowicz
    • Antti Kivimaki
    • Daniele Catone
    • Robert Richter
    2020 INTERNATIONAL JOURNAL OF MASS SPECTROMETRY

    The photofragmentation of the isoxazole molecules producing ionized atomic and molecular fragments was investigated in the photon energy range of 9e32 eV, using synchrotron radiation excitation combined with ion time-of-flight spectrometry. Twenty-one well resolved cations were identified in the mass spectra of the isoxazole, and their appearance energies were determined. The yield curves of these cations were obtained in the photon energy ranges from their appearance energies up to 32 eV. Moreover, the total ion yield of isoxazole was recorded with high precision in the photon energy range of 9.9e10.5 eV. This allowed the determination of the adiabatic ionization energy of 9.96 (0.02) eV in excellent agreement with earlier spectroscopic studies. Our results show that the dissociative ionization of isoxazole starts from the ring-opening and isomerization of isoxazole, and further it follows strictly through its ionic states. Possible ionic fragmentation channels yielding particular ions are discussed.

  • Validation Process for Computational Model of Full-Scale Segment for Design of Composite Footbridge
    • Tomasz Ferenc
    • Tomasz Mikulski
    2020 Full text Polish Maritime Research

    Experimental tests and numerical simulations of a full-scale segment of a foot and cycle bridge made of polymer composites are presented in the paper. The analysed structure is made of sandwich panels, which consist of glass fibre reinforced polymer (GFRP) multi-layered laminate faces and a PET foam (obtained from recycling) core. The dimensions of the segment cross-section are the same as for the target footbridge; however, span length was reduced to 3 m. The experimental tests were conducted in a laboratory of the Faculty of Ocean Engineering and Ship Technology at Gdansk University of Technology. A single vertical force was generated by a hydraulic cylinder and was applied to the platform of the structure. The experimental tests were supported by numerical analyses performed in Femap with NX Nastran software by means of the finite element method (FEM). Results obtained in the computational model were compared with results from experiments. Thus, the numerical model was validated and the obtained conclusions were used in the next step of the design process of a composite footbridge with a span length of 14.5 m.

  • Variable‐fidelity modeling of antenna input characteristics using domain confinement and two‐stage Gaussian process regression surrogates
    • Pieter Jacobs
    • Sławomir Kozieł
    2020 Full text INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS

    The major bottleneck of electromagnetic (EM)-driven antenna design is the high CPU cost of massive simulations required by parametric optimization, uncertainty quantification, or robust design procedures. Fast surrogate models may be employed to mitigate this issue to a certain extent. Unfortunately, the curse of dimensionality is a serious limiting factor, hindering the construction of conventional data-driven models valid over wide ranges of the antenna parameters and operating conditions. This paper proposes a novel surrogate modeling approach that capitalizes on two recently proposed frameworks: the nested kriging approach and two-stage Gaussian process regression (GPR). In our methodology, the first-level surrogate of nested kriging is applied to define the confined domain of the model in which the final surrogate is constructed using two-stage GPR. The latter permits blending information from a sparsely-sampled high-fidelity EM simulation model and a densely-sampled low-fidelity (or coarse-mesh) model. This combination enables significant computational savings in terms of training data acquisition while retaining excellent predictive power of the surrogate. At the same time, the proposed framework inherits all the benefits of nested kriging, including ease of uniform sampling of the confined domain as well as straightforward generation of a good initial design for surrogate model optimization. Comprehensive benchmarking carried out using two antenna examples demonstrates superiority of our technique over conventional surrogates (unconfined domain), and standard GPR applied to the confined domain. Application examples for antenna optimization are also provided.

  • Vehicle Detection with Self-Training for Adaptative Video Processing Embedded Platform
    • Sebastian Cygert
    • Andrzej Czyżewski
    2020 Full text Applied Sciences-Basel

    Traffic monitoring from closed-circuit television (CCTV) cameras on embedded systems is the subject of the performed experiments. Solving this problem encounters difficulties related to the hardware limitations, and possible camera placement in various positions which affects the system performance. To satisfy the hardware requirements, vehicle detection is performed using a lightweight Convolutional Neural Network (CNN), named SqueezeDet, while, for tracking, the Simple Online and Realtime Tracking (SORT) algorithm is applied, allowing for real-time processing on an NVIDIA Jetson Tx2. To allow for adaptation of the system to the deployment environment, a procedure was implemented leading to generating labels in an unsupervised manner with the help of background modelling and the tracking algorithm. The acquired labels are further used for fine-tuning the model, resulting in a meaningful increase in the traffic estimation accuracy, and moreover, adding only minimal human effort to the process allows for further accuracy improvement. The proposed methods, and the results of experiments organised under real-world test conditions are presented in the paper.

  • Verification of GNSS Measurements of the Railway Track Using Standard Techniques for Determining Coordinates
    • Cezary Specht
    • Andrzej Wilk
    • Władysław Koc
    • Krzysztof Karwowski
    • Paweł Dąbrowski
    • Mariusz Specht
    • Sławomir Grulkowski
    • Piotr Chrostowski
    • Jacek Szmagliński
    • Krzysztof Czaplewski
    • Jacek Skibicki
    • Sławomir Judek
    • Roksana Licow
    2020 Full text Remote Sensing

    The problem of the reproduction of the railway geometric layout in the global spatial system is currently solved in the form of measurements that use geodetic railway networks and also, in recent years, efficient methods of mobile positioning (mainly satellite and inert). The team of authors from the Gdańsk University of Technology and the Maritime University in Gdynia as part of the research project InnoSatTrack is looking for effective and efficient methods for the inventory of railway lines. The research is part of a wider investigation BRIK (Research and Development in Railway Infrastructure, in polish: Badania i Rozwój w Infrastrukturze Kolejowej). This paper presents a comparative analysis of the problem of the reproduction of the trajectory of the measuring system using tacheometry, satellite measurements made using a measurement trolley, and mobile satellite measurements. Algorithms enabling the assessment of the compliance of satellite measurements with classic tacheometric measurements were presented. To this end, the authors held measurement sessions using modern geodetic instruments and satellite navigation on a section of the railway line. The results of the measurements indicate the convergence of the level of accuracy achieved by different measuring techniques.

  • Vibration and buckling characteristics of nonlocal beam placed in a magnetic field embedded in Winkler–Pasternak elastic foundation using a new refined beam theory: an analytical approach
    • Subrat Kumar Subrat
    • S. Chakraverty
    • Mohammad Malikan
    2020 Full text European Physical Journal Plus

    In this article, a new refined beam theory, namely one variable first-order shear deformation theory, has been employed to study the vibration and buckling characteristics of nonlocal beam. The beam is exposed to an axial magnetic field and embedded in Winkler–Pasternak foundation. The von Kármán hypothesis along with Hamilton’s principle has been implemented to derive the governing equations for both the vibration and buckling studies, and closed-form solutions are obtained for simply supported beam using the Navier’s approach. Further, a parametric study has been conducted to explore the impacts of small-scale parameter, Winkler modulus, shear modulus and magnetic field intensity on natural frequencies and critical buckling loads.

  • Virtual inertia in Electric Power System
    • Zbigniew Lubośny
    2020 Automatyka Elektryka Zakłócenia

    The article presents the idea of introducing virtual inertia system to the electric power systems. The virtual inertia aim is to reduce or eliminate the effect of reducing the inertia of the power system as a result of replacing classic electricity generating units with renewable renergy sources (RES). The considerations are ilustrated by a computational example.

  • Virtual reality technology in architectural education
    • Agnieszka Gębczyńska-Janowicz
    2020 Full text World Transactions on Engineering and Technology Education

    Contemporary virtual reality (VR) technology allows the recreation of non-existent architectural objects of which there may be no trace remaining. Virtual reality applications allow access to digital models, which visualise the lost architecture. The popularity of VR has resulted in it being applied not only to computer games, but also in visualising the past. Maps allow movement through historical trails and 3D models of architecture that no longer exist can be activated on tablets that allow topographic points of modern space to be overlaid with virtual perspectives of historical architecture. In the future, such technology will be applied to develop outdoor exhibitions in memorial sites. They are nowadays used by students during classes in architectural and urban design, so as to make the visualisation of design issues more interesting. The aim of this article is to review the possibilities of the application of VR technologyin student projects in architectural education.

  • Virtual reality tools in teaching the conservation and history of Polish architecture
    • Szymon Kowalski
    • Piotr Samól
    • Robert Hirsch
    2020 Full text World Transactions on Engineering and Technology Education

    Virtual reality and its impact on teaching conservation and architectural history is the subject of this article. During the COVID-19 crisis in 2020, the education of students of architecture was transferred by Gdańsk University of Technology (GUT), Gdańsk, Poland, to distance learning. This method has provided academics an opportunity to examine the impact of virtual reality and remote education on architectural history and conservation. The outcome of that examination - not of graphical skills typical of architecture - but rather of spatial imagination in a three-dimensional environment is presented and discussed in this article.

  • Virulence, antifungal susceptibility and molecular mechanisms of echinocandin resistance among Candida isolates recovered from clinical specimens
    • Martyna Mroczyńska
    2020

    Fungi of the genus Candida belong to the natural microflora of healthy individuals. However, they can also be a cause of opportunistic infections especially among patients with an impaired immune system. The first line therapy of Candida infections is based on triazoles. However, in recent years there an increase of azole resistant Candida spp., in particular C. glabrata and C. krusei, has been observed. For this reason, echinocandin drugs are increasingly being used. Epidemiological studies conducted around the world indicate a low level of Candida resistance to echinocandins. However, echinocandin resistance for C. glabrata is still increasing and in 2015 it was estimated to be over 13%. In the presented PhD dissertation, the echinocandin susceptibility tests was performed for the first time on a microdilution broth of 242 Candida isolates collected from Polish hospitals, and resulted in the finding that 6.6% of isolates are echinocandin resistant. Moreover, the molecular mechanism was investigated by the examination of the mutations occurring in the FKS1 gene encoding the glucan synthase – the molecular target of echinocandin. The FKS1 gene mutation (T4072C) that contributes to echinocandin resistance has been identified in single C. albicans and C. inconspicua isolates. Another part of this research was to investigate the influence of anidulafungin and micafungin exposure to the susceptibility to echinocandin and the expression level of CHS1, CRZ1, CRZ2, UTR2 and HSP90 genes. Anidulafungin exposure cause the overexpression of CHS1 and CRZ2. After the exposure of anidulafungin and then the removal of this compound from the medium the expression level of CHS1, UTR2 and CRZ1 was higher than the initial expression of these genes. The pathogenicity of Candida isolates was also tested using Galleria mellonella larvae as the host organism. The obtained results were compared with the enzymatic activity of different virulence factors. Mortality of G. mellonella larvae infected with different Candida species was distinguished between virulent and non-virulent phenotypes. C. albicans were the most pathogenic species and produced the highest amount of virulence factors, while most C. parapsilosis isolates were avirulent. The pathogenicity of Candida isolates examined in G. mellonella larvae is correlated with protease, haemolysins and esterase activity among Candida clinical isolates.

  • Visual Capacity Assessment of the Open Landscape in Terms of Protection and Shaping: Case Study of a Village in Poland
    • Anna Górka
    2020 Full text Sustainability

    This article describes the methodology and results of research on landscape visual capacity. The aim of the project was to develop a tool that would support planning and design decisions at the level of communal management in rural areas in Poland through systematic application of visual criteria. Their importance in the protection, management and shaping of space is underlined by the document produced at the European Landscape Convention of 2000 (ELC). To date, ELC recommendations have not been fully implemented in Poland. The author of the study used the methods of the Krakow School of Landscape Architecture in assessing cultural landscapes and referred to the assumptions of the British Landscape Character Assessment (LCA). The analysis was based on the results of a landscape identification conducted in a part of the Cekcyn commune. The assessment of visual capacity was conducted for the village of Nowy Sumin, located in that commune. The eect of the study is the classification of open landscapes with respect to the assessment of visual changes resulting from potential residential development. The results obtained prompt the conclusion that the applied method can eectively support local spatial planning as it takes national conditions into account.

  • Visual Content Representation for Cognitive Systems: Towards Augmented Intelligence
    • Caterine Silva de Oliveira
    • Cesar Sanin
    • Edward Szczerbicki
    2020

    Cognitive Vision Systems have gained significant attention from academia and industry during the past few decades. One of the main reasons behind this interest is the potential of such technologies to revolutionize human life since they intend to work robustly under complex visual scenes (which environmental conditions may vary), adapting to a comprehensive range of unforeseen changes, and exhibiting prospective behavior. The combination of these properties supports the creation of more intelligent and efficient environments by mimicking the human capabilities. Nonetheless, preserving the environment involves gathering visual and other sensorial information and translating it into knowledge to be useful, which still remains a challenge for real time cognitive vision applications due to the complexity of such process. Experts believe the starting point is to establish a knowledge representation for Cognitive Vision technologies as a unique standard that could integrate image/video modularization and virtualization, together with information from other sources (wearable sensors, machine signals, context, etc.) and capture its knowledge. In this chapter, we present a multi-domain knowledge structure based on experience, which can be used as a comprehensive embedded knowledge representation for Cognitive Vision System, addressing the representation of visual content issue and facilitating its reuse. In addition, a successful representation and management of knowledge in cognitive systems would support communication and collaboration between humans and machines, for increased learning capabilities and enhanced decision making; this concept is a pathway towards what is called Augmented Intelligence. The implementation of such representation has been tested in a Cognitive Vision Platform for Hazard Control (CVP-HC) to address the issue of workers’ exposure to risks in industrial environments, in special for the non-use of personal protective equipment, facilitating knowledge engineering processes through a flexible and adaptable implementation.

  • Visual TreeCmp : Comprehensive Comparison of Phylogenetic Trees on the Web
    • Tomasz Goluch
    • Damian Bogdanowicz
    • Krzysztof Giaro
    2020 Full text Methods in Ecology and Evolution

    1. We present Visual TreeCmp—a package of applications for comparing phylogenetic tree sets. 2. Visual TreeCmp includes a graphical web interface allowing the visualization of compared trees and command line application extended by comparison methods recently proposed in the literature. 3. The phylogenetic tree similarity analysis in Visual TreeCmp can be performed using eighteen metrics, of which 11 are dedicated to rooted trees and seven to the un-rooted ones. Additionally, in the case of different sets of labels, the compared trees can be pruned so that the sets are identical. 4. The Visual TreeCmp is dedicated to people who need a universal and easy-to-use tool designed to compare arbitrary (not necessary binary) phylogenetic trees. An example of its use in a supertree accuracy analysis is described in section 3. 5. The Visual TreeCmp package Web application is available at: (https://eti.pg.edu.pl/TreeCmp), and its source codes available under the GNU license can be reached through several repositories located at: (https://github.com/TreeCmp)

  • VUV photofragmentation of the six-membered heterocyclic molecules containing oxygen
    • Michał Jurkowski
    • Antti Kivimaki
    • Robert Richter
    • Tomasz Wąsowicz
    2020 Synchrotron Radiation in Natural Science

    Cancer is a significant public health concern worldwide, which results in millions of deaths each year. The standard cure routine for cancer is surgery, and nowadays, radiotherapy or a hadrontherapy. Depending on the type of cancer, patients may undergo additional treatment, including targeted therapy. A combination of radio- or hadron-therapy with proper drug treatment can inhibit the proliferation of cancer cells and thus can significantly improve survival rates. This is because the interaction of radiation on those drugs can lead to their fragmentation, which additionally increases the number of reactive species that interact with the adjacent medium. For example, anthracyclines, a class of drugs build on tetrahydropyran ring, are broad-spectrum antitumor agents that induce, among other things, indirect damage to DNA via reactions involving reactive oxygen species.

  • Wage response to global production links: evidence for workers from 28 European countries (2005–2014)
    • Aleksandra Parteka
    • Joanna Wolszczak-Derlacz
    2020 Full text REVIEW OF WORLD ECONOMICS

    Using rich individual-level data on workers from 28 European countries, this study provides the first so extensive cross-country assessment of wage response to global production links within GVC in the period 2005–2014. Unlike the other studies, the authors (i) address the importance of backward linkages in globally integrated production structures (capturing imports of goods and services needed in any stage of the production of the final product); (ii) measure occupational task profile of workers with country-specific indices of routinisation; (iii) compare the impact of global production links on wages between workers from Western, Central-Eastern and Southern Europe; employed in manufacturing and non-manufacturing sectors; (iv) account for direct and indirect dependence on GVC imports from developing and high-income countries. The study takes into account the potential endogeneity issues. The results suggest that global import intensity of production exhibits negative pressure on wages in Europe. This effect concerns mainly workers from Western Europe employed in manufacturing and is driven by production links with non-high income countries but our counterfactual estimates suggest that the effect is economically small.

  • Waste Rubber Pyrolysis: Product Yields and Limonene Concentration
    • Katarzyna Januszewicz
    • Paweł Kazimierski
    • Tomasz Suchocki
    • Dariusz Kardaś
    • Witold Lewandowski
    • Ewa Klugmann-Radziemska
    • Justyna Łuczak
    2020 Full text Materials

    Tires, conveyor belts, floor mats, and shoe soles form a main-stream of rubber waste. The amount of these used materials continuously increases due to development of the rubber market. Therefore, pro-ecological utilization (i.e., energy recycling instead of burning) and recovering valuable and recyclable materials becomes an urgent necessity. In this regard, this work was devoted to the chemical recycling of selected used rubber products, and it especially explores the possibility of limonene production. Different types of waste rubber were characterized and pyrolyzed at microgram and laboratory scales, and the results were compared. Additionally, the pyrolysis of tires, the most significant stream of rubber waste, was also conducted in a semi-technical scale reactor. The effectiveness of limonene formation in the liquid fractions obtained from different types of waste rubber was compared.

  • Waste tire rubber as low-cost and environmentally-friendly modifier in thermoset polymers – a review
    • Aleksander Hejna
    • Jerzy Korol
    • Marta Przybysz-Romatowska
    • Łukasz Zedler
    • Błażej Chmielnicki
    • Krzysztof Formela
    2020 Full text WASTE MANAGEMENT

    Nowadays, waste tire rubber (WTR) management is a growing and serious problem. Therefore, research works focused on the development of cost-effective and environmentally-friendly methods of WTR recycling are fully justified. Incorporation of WTR into polymer matrices and composite materials attracts much attention, because this approach allows sustainable development of industrially applicable waste tires recycling technologies. Generally, utilization of WTR as a filler for polymer composites noticeably reduces materials costs, while suitable modification/functionalization of WTR may significantly enhance the performance of plastics and rubbers. This work aims to summarize the literature reports related to the thermoset/WTR composites based on various matrices such as: polyurethanes, epoxy and other resins. It particularly focuses on compatibilization strategies in thermosets/WTR systems and their impact on the chemistry and physical interfacial interactions between thermoset matrix and WTR filler phase, what significantly affecting performance properties of prepared materials. Moreover, future trends and limitation related to thermoset/WTR composites development are discussed.

  • Waste Tyres Pyrolysis for Obtaining Limonene
    • Katarzyna Januszewicz
    • Paweł Kazimierski
    • Wojciech Kosakowski
    • Witold Lewandowski
    2020 Full text Materials

    This review deals with the technologies of limonene production from waste tyre pyrolysis. Thermal decomposition is attractive for tackling the waste tyre disposal problem, as it enables both: energy to be recovered and limonene to be obtained. This material management recycling of tyres is environmentally more beneficial than the burning of all valuable products, including limonene. Given this recoverability of materials from waste tyres, a comprehensive evaluation was carried out to show the main effect of process conditions (heating rate, temperature, pressure, carrier gas flow rate, and type of volatile residence and process times) for different pyrolytic methods and types of apparatus on the yield of limonene. All the results cited are given in the context of the pyrolysis method and the type of reactor, as well as the experimental conditions in order to avoid contradictions between different researchers. It is shown that secondary and side reactions are very sensitive to interaction with the above-mentioned variables. The yields of all pyrolytic products are also given, as background for limonene, the main product reported in this study.

  • Wavelet Transform Analysis of Heart Rate to Assess Recovery Time for Long Distance Runners
    • Grzegorz Redlarski
    • Janusz Siebert
    • Marek Krawczuk
    • Arkadiusz Żak
    • Ludmiła Danilowicz-szymanowicz
    • Łukasz Doliński
    • Piotr Gutknecht
    • Bartosz Trzeciak
    • Wojciech Ratkowski
    • Aleksander Pałkowski
    2020 Full text Electronics

    The diagnostics of the condition of athletes has become a field of special scientific interest and activity. The aim of this study was to verify the effect of a long (100 km) run on a group of runners, as well as to assess the recovery time that is required for them to return to the pre-run state. The heart rate (HR) data presented were collected the day before the extreme physical effort, on the same day as, but after, the physical effort, as well as 24 and 48 h after. The Wavelet Transform (WT) and the Wavelet-based Fractal Analysis (WBFA) were implemented in the analysis. A tool was constructed that, based on quantitative data, enables one to confirm the completion of the recovery process that is related to the extreme physical effort. Indirectly, a tool was constructed that enables one to confirm the completion of the recovery process. The obtained information proves that the return to the resting state of the body after a significant physical effort can be observed after two days entirely through the analysis of the HR. Certain practical measures were used to differentiate between two substantially different states of the human body, i.e., pre- and post-effort states were constructed. The obtained results allow for us to state that WBFA appears to be a useful and robust tool in the determination of hidden features of stochastic signals, such as HR time signals. The proposed method allows one to differentiate between particular days of measurements with a mean probability of 92.2%.

  • We are in touch
    • Krzysztof Wróblewski
    2020

    In Touch - opis pracy „Dłonie stanowią część indywidualnej osobowości i charakteru, ale wykonują również swoje niezależne działania, i jako wyposażone we własny język, mają kluczowe znaczenie dla ludzkiej komunikacji.” Myśląca dłoń, J. Pallasmaa Obraz In Touch powstał z potrzeby zbudowania metafory czasu, którego aktualnie doświadczamy. Popularny w języku angielskim, wyrażający intencję pozostania w kontakcie, zwrot we are in touch zawiera w sobie problematyczny obecnie rzeczownik „dotyk”. Dłoń, część naszego ciała, która jest jednym z podstawowych narzędzi komunikowania emocji oraz materializacji myśli, została wyrugowana z przyjętego rytuału witania się, ponieważ nagle obarczono ją winą za przekazywanie zarazy. Nasze palce odczuwające subtelność materii pokryły lateksowe izolatory. Podniesiona dłoń pozostaje jeszcze gestem pozdrowienia, ale zaczęła też wyrażać komunikat – trzymaj dystans! nie zbliżaj się! Poprosiłem pewną grupę moich przyjaciół, znajomych i bliskich mieszkających w Gdańsku oraz w innych częściach Polski i poza jej granicami, aby obrysowali obie swoje dłonie, a następnie przesłali zdjęcie konturów Internetem lub jako SMS. Z niektórymi spotykam się sporadycznie, z innymi często. Dzięki ich partycypacji ze zbioru zarysów rąk kobiet, mężczyzn oraz dzieci w różnym wieku ułożyłem kompozycję zajmującą lewą połowę obrazu In Touch. Kontury przeniesionych na płótno dłoni zachowałem w skali 1:1, oddając przy tym indywidualną aurę każdej osoby. Na pierwszy rzut oka dłonie mają przywodzić na myśl porozrzucane rękawiczki. Ich układ tworzy arytmiczny ornament. Po prawej stronie obrazu znajdują się zbudowane z układu trójkątów nieregularne geometryczne figury. Można je interpretować na wiele sposobów – przypominają zamaskowane twarze, ale też komórki tkanek albo jakieś struktury krystaliczne. Chciałem, aby całość, tzn. lewa i prawa strona obrazu, nasuwała skojarzenie z miękką, koronkową siatką przypominającą firankę, która częściowo zasłania, ale też jest przezierna. Inspiracją do namalowania obrazu In Touch była aura negatywów dłoni znajdujących się wśród prehistorycznych malunków, m.in. w grotach Lascaux i Altamiry. Sylwety dłoni niczym fotografie zachowały indywidualne cechy osób. Ukryte w ziemi przetrwały tysiące lat, świadcząc o atawistycznej potrzebie zostawienia po sobie śladu przez ludzi próbujących, tak jak my teraz, zrozumieć własną egzystencję. Krzysztof Wróblewski Gdańsk, maj 2020

  • Weak localization competes with the quantum oscillations in a natural electronic superlattice: The case of Na1.5(PO2)4(WO3)20
    • Kamil Kolincio
    • Olivier Pérez
    • Enric Canadell
    • Pere Alemany
    • Elen Duverger-Nédellec
    • Arianna Minelli
    • Alexei Bosak
    • Alain Pautrat
    2020 Full text PHYSICAL REVIEW B

    We report an investigation of the combined structural and electronic properties of the bronze Na1.5(PO2)4(WO3)20. Its low-dimensional structure and possible large reconstruction of the Fermi surface due to charge density wave instability make this bulk material a natural superlattice with a reduced number of carriers and Fermi energy. Signatures of multilayered two-dimensional (2D) electron weak localization are consequently reported, with an enhanced influence of quantum oscillations. A crossover between these two antagonistic entities, previously observed only in genuine low-dimensional materials and devices, is shown to occur in a bulk crystal due to its hidden 2D nature.

  • Weak Solutions within the Gradient-Incomplete Strain-Gradient Elasticity
    • Victor Eremeev
    • Francesco dell'Isola
    2020 Full text Lobachevskii Journal of Mathematics

    In this paper we consider existence and uniqueness of the three-dimensional static boundary-value problems in the framework of so-called gradient-incomplete strain-gradient elasticity. We call the strain-gradient elasticity model gradient-incomplete such model where the considered strain energy density depends on displacements and only on some specific partial derivatives of displacements of first- and second-order. Such models appear as a result of homogenization of pantographic beam lattices and in some physical models. Using anisotropic Sobolev spaces we analyze the mathematical properties of weak solutions. Null-energy solutions are discussed.

  • Wear of electroplated diamond tools in lap-grinding of Al2O3 ceramic materials
    • Mariusz Deja
    • Dawid Zieliński
    2020 Full text WEAR

    Current development of modern products, together with ever-increasing demands for their operation and usage, necessitate the search for new processing methods. Abrasive machining is widely used in many industrial areas, especially for processing difficult-to-machine materials such as advanced ceramics. Grinding with lapping kinematics, also called lap-grinding, is still one of the innovative methods of abrasive processing being under continuous development. It combines the advantages of grinding and lapping, allowing for meeting high design requirements and, at the same time, ensuring efficient and safe machining. This paper presents experimental and modelling results on the application of electroplated wheels with diamond grains (D107 and D64) in the lapgrinding of Al2O3 ceramic materials in a single-disc lapping machine configuration. The grain size along with the thickness of the nickel bond influenced the material removal rate and surface roughness obtained. The relationship between the material removal and the processing time was approximated by asymptotic mathematical functions. Moreover, the empirical models were modified according to the Preston’s equation when the unit pressure increased. The linear and nonlinear regression models enabled accurate curve fitting to the surface roughness data. Microscopic images of the active surface of electroplated diamond tools were analyzed in the aspects of the resultant tool wear and technological effects. In addition, the results were referred to the analysis of microscopic images of the suspension taken from the active surface of the tool after subsequent tests. The suspension consisted of particles of fragmented abrasive grains as well as chips removed from the machined surface.

  • Wear Resistance Enhancement of Al6061 Alloy Surface Layer by Laser Dispersed Carbide Powders
    • Rafał Jendrzejewski
    • Jacek Łubiński
    • Gerard Śliwiński
    2020 Full text Materials

    In this paper, results of the experimental study on improving wear resistance in sliding friction of Al-based alloy are presented. The technique used involves the formation of a metal matrix composite (MMC) in the alloy surface layer by laser dispersion of carbide powders such as WC, TiC and SiC. For WC and TiC MMC surface coatings fabricated under conditions typical for most of the technologically relevant solid-state lasers (wavelength range of 0.8–1.1 μm), the nearly inversely proportional dependence of the required laser energy density on the powder mass density is observed. Highly homogenous distribution of powder particle content (up to 40%) in the MMC surface coatings of a thickness between 0.8 and 1.6 mm obtained by multiple scanning is observed in the cross-section of specimens processed within a rather narrow parameter window. Tribological tests and comparison to untreated material reveal wear resistance increases by five- and ten-fold, observed in samples with laser-dispersed TiC and WC powders, respectively. Results indicate that substantial modification and reinforcement of the surface layer can be achieved in Al alloy in a one-step process without substrate preheating.

  • Weighted Clustering for Bees Detection on Video Images
    • Julian Szymański
    • Jerzy Dembski
    2020 Full text

    This work describes a bee detection system to monitor bee colony conditions. The detection process on video images has been divided into 3 stages: determining the regions of interest (ROI) for a given frame, scanning the frame in ROI areas using the DNN-CNN classifier, in order to obtain a confidence of bee occurrence in each window in any position and any scale, and form one detection window from a cloud of windows provided by a positive classification. The process has been performed by a method of weighted cluster analysis, which is the main contribution of this work. The paper also describes a process of building the detector, during which the main challenge was the selection of clustering parameters that gives the smallest generalization error. The results of the experiments show the advantage of the cluster analysis method over the greedy method and the advantage of the optimization of cluster analysis parameters over standard-heuristic parameter values, provided that a sufficiently long learning fragment of the movie is used to optimize the parameters.

  • Werner Siemens i jego upamiętnienie
    • Dariusz Świsulski
    2020 Wiadomości Elektrotechniczne

    Werner Siemens żył w latach 1816-1892, w czasach niezwykłego postępu w naukach przyrodniczych i największych odkryć w zakresie elektrotechniki. Jako osoba z wykształceniem technicznym i niezwykłym zacięciem naukowym, przez całe życie łączył te dwie działalności. Jego prace naukowe służyły rozwojowi techniki, a wdrażane rozwiązania techniczne wymuszały tematy prowadzonych badań. Wykazał się też talentem jako przedsiębiorca. Założone przez niego w Niemczech, ale też Rosji, czy Anglii firmy funkcjonowały z sukcesami, stanowiąc podstawę działającego dzisiaj międzynarodowego koncernu Siemens AG. W artykule przypomniano najważniejsze osiągnięcia Wernera Siemensa, ilustrowane poświęconymi mu pamiątkami: medalami, plakietami i wydawnictwami pocztowymi.

  • WHAT DRIVES CROSS-COUNTRY DIFFERENCES IN EXPORT VARIETY? A BILATERAL PANEL APPROACH
    • Aleksandra Parteka
    2020 Full text ECONOMIC MODELLING

    A worldwide event like the 2020 Coronavirus outbreak can only reinforce the interest in modelling trade diversification as a key factor in countries’ vulnerability to external shocks. This paper adopts a detailed relative framework to study the determinants of product-level export variety in a large bilateral panel of developing and developed economies (16,770 country pairs in the period 1988–2014). We find that country pairs characterized by large differentials in productivity and in the makeup of the labour force differ in export variety patterns. This result holds after controlling for other endowments and for trade costs. Further, productivity plays a significant role in the reduction of export variety dissimilarities between countries belonging to different income groups. Hence, without successful technological convergence the low-income economies will not be able to reduce their exposure to export risk.

  • What fosters firm-level labour productivity in Eastern European and Central Asian countries?
    • Aleksandra Kordalska
    • Magdalena Olczyk
    2020 Full text Bank i Kredyt

    This study examines labour productivity performance and its determinants in Eastern European and Central Asian (EECA) firms using micro-level data. We find significant differences in labour productivity among members of the European Union in Eastern Europe and other Eastern European and Central Asian countries. We also confirm the important impact of foreign ownership, exporter status, and highly skilled workers on productivity levels. However, we reveal a non-linear relationship between firm age and labour productivity. Additionally, significant differences in labour productivity determinants between services and manufacturing are found. The productivity of service firms, unlike manufacturing firms, is much more sensitive to changes in productivity factors.

  • What Potential Entrepreneurs from Generation Y and Z Lack-IEO and the Role of EE
    • Julita Wasilczuk
    • Anita Richert-Kaźmierska
    2020 Full text Education Sciences

    This paper addresses the issue of individual entrepreneurship orientation (IEO) and entrepreneurship education (EE), which are both important for modern economic development. Intergenerational differences in these areas were discussed, especially characteristics of Generations Y and Z. The results of research conducted among 757 Polish students showing their IEO are presented. 80% of respondents displayed high levels of proactivity (primarily directed at meeting their own needs), whilst only 56% exhibited innovativeness and only 47% risk-taking. On the basis of the research results, the authors formulated recommendations for entrepreneurship education, aimed at strengthening IEO among representatives of Generations Y and Z.

  • Wirtualna rekonstrukcja Jaszczurki Gierłowskiej = Virtual reconstruction of Gierłowska’s Lizard
    • Jacek Lebiedź
    2020 Bursztynisko

    Gdańsk znany jest z posiadania wielu osobliwości. Jedną z nich jest niewielka, choć licząca aż 44 miliony lat jaszczurka (podrząd Sauria, rodzina Lacertidae) zatopiona w trzyipółcentymetrowej bryłce bursztynu bałtyckiego – sukcynitu. Określa się ją mianem Jaszczurki Gierłowskiej, jako że w czerwcu 1997 r. znalazła ją na gdańskich Stogach bursztynniczka Gabriela Gierłowska. Obecnie bursztyn z jaszczurką oglądać można w Muzeum Bursztynu będącym oddziałem Muzeum Gdańska. Jest to bodaj najbardziej znany eksponat tego muzeum.

  • Właściwości elektryczne i magnetyczne szkła Fe2O3 – SiO2 – PbO
    • Ariel Lenarciak
    2020 Full text

    Szkło Fe2O3–SiO2–PbO wydaje się być obiecującym materiałem do zastosowań w urządzeniach elektrycznych takich jak rdzenie cewek, czujniki pola magnetycznego oraz mikrotransformatory. Jest to spowodowane korzystnymi właściwościami takimi jak stosunkowo wysoka rezystywność oraz w miarę duża przenikalność magnetyczna. Pierwsza wymieniona cecha skutkuje brakiem strat energii na prądy wirowe. Natomiast druga cecha oznacza potencjalną przydatność materiału do zastosowań na rdzenie magnetyczne. Powszechnie stosowanymi w technice materiałami o podobnych właściwościach magnetycznych i elektrycznych do omawianych szkieł są ferryty. Szkła tlenkowe posiadające strukturę amorficzną mogą wykazywać inne cechy, być może korzystniejsze w niektórych zastosowaniach niż ferryty, a przez to rozszerzyć pulę dostępnych materiałów o nowych właściwościach. Wytworzono próbki szkła tlenkowego o składzie: x Fe2O3–50 SiO2–(50-x) PbO, gdzie x=12,5; 15; 17,5 za pomocą dwóch metod, to jest metody szybkiego chłodzenia i tradycyjnej metody wytopu. W toku pracy potwierdzono amorficzną strukturę wytworzonych próbek. Próbki poddano badaniom magnetyzacji stałoprądowej, spektroskopii impedancyjnej, skaningowej mikroskopii elektronowej wraz z spektroskopią dyspersji energii promieniowania rentgenowskiego, mikroskopii sił atomowych, mikroskopii sił magnetycznych, skaningowej kalorymetrii różnicowej, termograwimetrii, dylatometrii, rentgenowskiej spektroskopii fotoelektronów oraz dyfraktometrii rentgenowskiej. Zaproponowano mechanizmy przewodzenia elektrycznego w badanym szkle oraz uzyskano parametry procesu przewodnictwa elektrycznego. Zmierzono magnetyzację w funkcji pola magnetycznego i otrzymano pętle histerezy magnetycznej. Wyznaczono także temperatury zeszklenia próbek oraz ich współczynnik rozszerzalności termicznej. Przeanalizowano wpływ metody wytopu na strukturę, właściwości elektryczne i magnetyczne badanego szkła. Zaproponowano także wyjaśnienie niemonotonicznej zmiany przewodnictwa elektrycznego i magnetyzacji wraz ze wzrostem koncentracji tlenku żelaza przez klasterowanie jonów żelaza.

  • Wodór jako paliwo cz. 1
    • Bartosz Dawidowicz
    2020 Fizyka w Szkole

    W artykule przedstawiono wodór jako nowoczesny nośnik energii oraz jego zastosowanie techniczne w ujęciu konwersji energii. Przybliżono jego odkrycie, właściwości oraz jego wykorzystanie od odkrycia do współczesności. Dokonano opisu budowy i zasady działania ogniw paliwowych. Omówiono ich podział przedstawiając zalety i wady każdego rozwiązania oraz ich zastosowanie techniczne w zależności od typu ogniwa.

  • Wodór jako paliwo cz. 2
    • Bartosz Dawidowicz
    2020 Fizyka w Szkole

    W artykule scharakteryzowano aktualne i przyszłościowe metody wytwarzania wodoru. Przedstawiono problem związany z przechowywaniem wodoru oraz ukazano aktualne i przyszłościowe rozwiązania dotyczące magazynowania wodoru.

  • WORK MOTIVATION PROFILES AND WORK PERFORMANCE IN A GROUP OF CORPORATE EMPLOYEES: A TWO-STEP CLUSTER ANALYSIS
    • Beata Basińska
    2020 Full text Roczniki Psychologiczne

    Few studies have applied a person-centered approach to work motivation using cluster or profile analyses. Thus, little is known about which configurations of work motivations characterize professionals. The aim of this study is to establish the structure of work motivation profiles under the framework of self-determination theory and to examine the relationship between work motivation and subjective work performance. The study involved 147 corporate employees who completed the Multidimensional Work Motivation Scale and self-rated their work performance. The two-step cluster analysis was applied, followed by a one-way ANOVA and a post-hoc Bonferroni test. The findings revealed differences between the five profiles for all forms of motivational regulation on the self-determination continuum (large effect sizes). Further examination revealed that the employees’ current work performances differed across motivational profiles (medium effect size). Strongly and poorly motivated as well as autonomously motivated employees reported better subjective work performance compared to unmotivated individuals. In line with self-determination theory, the quantity and shape of motivation can be simultaneously considered in terms of both theoretical and practical implementation.

  • Wpływ błędów projektowych, wykonawczych oraz sposobu eksploatacji na trwałość podłóg przemysłowych
    • Maciej Niedostatkiewicz
    • Tomasz Majewski
    2020 Full text Izolacje

    Celem artykułu jest wskazanie najczęściej popełnianych błędów przy projektowaniu podłóg przemysłowych. Artykuł stanowi częśc 1 serii publikacji. Artykuł ma charakter studium przypadku i został ograniczony do wybranych przypadków z praktyki inżynierskiej

  • Wpływ błędów projektowych, wykonawczych oraz sposobu eksploatacji na trwałość podłóg przemysłowych
    • Maciej Niedostatkiewicz
    • Tomasz Majewski
    2020

    W artykule przedstawiono syntetyczna analizę przyczyn obniżonej trwałośc ibetonowych posadzek przemysłowych. Podano inżynierskie spsobu usuwania usterek i uszkodzeń będących następstwem niedociągnięć i błędów projektowych, wykonawczych, jak również niewłaściwego sposobu eksploatacji