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  • Time Domain Modeling of Propeller Forces due to Ventilation in Static and Dynamic Conditions
    • Anna Kozłowska
    2020 Pełny tekst Journal of Marine Science and Engineering

    This paper presents experimental and theoretical studies on the dynamic effect on the propeller loading due to ventilation by using a simulation model that generates a time domain solution for propeller forces in varying operational conditions. For ventilation modeling, the simulation model applies a formula based on the idea that the change in lift coefficient due to ventilation computes the change in the thrust coefficient. It is discussed how dynamic effects, like hysteresis effects and blade frequency dynamics, can be included in the simulation model. Simulation model validation was completed by comparison with CFD (computational fluid dynamics) calculations and model experiments. Experiments were performed for static and dynamic (heave motion) conditions in the large towing tank at the SINTEF Ocean in Trondheim and in the Marine Cybernetics Laboratories at NTNU (Norwegian University of Science and Technology). The main focus of this paper is to explain and validate the prediction model for thrust loss due to ventilation and out of water effects in static and dynamic heave conditions.

  • TiO2-based magnetic nanocomposites with core-shell structure
    • Zuzanna Bielan
    2020 Pełny tekst

    The main aim of the doctoral dissertation was preparation and characterization of photocatalysts, with particular emphasis on modified titanium (IV) oxide photocatalysts, which can be applied for the degradation of organic pollutants not susceptible to biodegradation. A particularly important aspect of the work was the development of preparation method of nanocomposites with the magnetic core-shell and photocatalyst shell (TiO2) structure, photocatalytic active under UV/Vis radiation. The use of the microemulsion method for the preparation of magnetic nanocomposites allowed for the creation of the desired structure, in which the core of the nanocomposite was iron (II) diiron (III), (Fe3O4), covered with a layer of inert silica and TiO2 photocatalyst. The second scientific aspect of the work was to increase the photocatalytic activity of the obtained nanocomposites in UV/Vis light and visible light by modifying the titanium(IV) oxide surface with platinum and copper, as well as introducing titanium defects into the crystal structure of TiO2. The obtained nanocomposites were used for the effective degradation of persistent organic pollutants present in flowback water after the hydraulic fracturing process and carbamazepine, a commonly used antiepileptic drug, classified as a pharmaceutical pollutant of the aquatic environment.

  • To Survive in a CBRN Hostile Environment: Application of CAVE Automatic Virtual Environments in First Responder Training
    • Paweł Maciejewski
    • Małgorzata Gawlik-Kobylińska
    • Jacek Lebiedź
    • Witold Ostant
    • Doğan Aydın
    2020

    This paper is of a conceptual nature and focuses on the use of a specific virtual reality environment in civil-military training. We analyzed the didactic potential of so-called CAVE automatic virtual environments for First Responder training, a type of training that fills the gap between First Aid training and the training received by emergency medical technicians. Since real training involves live drills based on unexpected situations, it is expensive and difficult to organize. We propose the application of virtual environments of three different sizes to increase the effectiveness of First Responder training. Our findings show that using the CAVEs allows for easier adaptation of the learning environment to a specific scenario while reducing costs from preparing training fields. The environments are also safer for trainees who must perform tasks related to hazardous materials. The analysis was based on the facilities at the Immersive 3D Visualization Lab (I3DVL) at Gdańsk University of Technology in Poland. We believe that, in the context of emerging threats of chemical, biological, radiological, and nuclear terrorism, such training is a necessity. The application of artificial intelligence can be considered as a further step in the facility development to increase the training fidelity.

  • Toksyny grzybów kapeluszowych. Rozdz. 10
    • Roman Kotłowski
    2020

    W rozdziale nr 10 brak abstraktu

  • Tool Wear Prediction in Single-Sided Lapping Process
    • Norbert Piotrowski
    2020 Pełny tekst Machines

    Single-sided lapping is one of the most effective planarization technologies. The process has relatively complex kinematics and it is determined by a number of inputs parameters. It has been noted that prediction of the tool wear during the process is critical for product quality control. To determine the profile wear of the lapping plate, a computer model which simulates abrasive grains trajectories was developed in MATLAB. Moreover, a data-driven technique was investigated to indicate the relationship between the tool wear uniformity and lapping parameters such as the position of conditioning rings and rotational speed of the lapping plate and conditioning rings.

  • Toolchain Modeling: Comprehensive Engineering Plans for Industry 4.0
    • Geza Kulcsar
    • Marek Tatara
    • Federico Montori
    2020 Pełny tekst

    The fourth industrial revolution (Industry 4.0) elevates the complexity and autonomy of industrial systems and engineering environments to levels not seen before. The novel challenges involve not only the software running on the partaking autonomous devices, but also architectural considerations and the technological infrastructure around the entire engineering process. In this paper, complementing the trends in industrial systems design, we propose an approach to toolchain modeling, i.e. an integrated specification for the interoperability of tools along with the holistic architectural framework, designed in the context of the Arrowhead Framework. In particular, we propose an intuitive, yet founded definition for toolchains and their mappings to a versatile engineering process model. Those definitions then serve as a basis for proposing our comprehensive toolchain modeling approach. The methodology is demonstrated using (simplified) real-world engineering case studies based on the Arrowhead Framework and platform.

  • Topological degree for equivariant gradient perturbations of an unbounded self-adjoint operator in Hilbert space
    • Piotr Bartłomiejczyk
    • Bartosz Kamedulski
    • Piotr Nowak-Przygodzki
    2020 Pełny tekst TOPOLOGY AND ITS APPLICATIONS

    We present a version of the equivariant gradient degree defined for equivariant gradient perturbations of an equivariant unbounded self-adjoint operator with purely discrete spectrum in Hilbert space. Two possible applications are discussed.

  • Torsional stability capacity of a nano-composite shell based on a nonlocal strain gradient shell model under a three-dimensional magnetic field
    • Mohammad Malikan
    • Maxim Krasheninnikov
    • Victor Eremeev
    2020 Pełny tekst INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE

    This paper considers a single-walled composite nano-shell (SWCNS) exposed in a torsional critical stability situation. As the magnetic field affects remarkably nanostructures in the small size, a three-dimensional magnetic field is assessed which contains magnetic effects along the circumferential, radial and axial coordinates system. Based on the results of the nonlocal model of strain gradient small-scale approach and the first-order shear deformation shell theory (FSDST), the problem is estimated. Afterward, the numerical results are taken analytically and compared with other existing literature. Hereafter, the influences of various factors, such as the magnetic field, are discussed deeply. It is observed that when the magnetic field is studied in three dimensions, the transverse magnetic effect is the most serious factor that affects fundamentally the torsional stability of the shell.

  • Total cross section measurements for electron scattering from tin(IV) chloride (SnCl4)
    • Paweł Możejko
    • Sylwia Stefanowska-Tur
    • Elżbieta Ptasińska-Denga
    • Czesław Szmytkowski
    2020 Pełny tekst Journal of Physics : Conference Series

    Total cross section for electron scattering from SnCl4 molecules has been measured for energies from 0.6 to 300 eV. Obtained results have been compared with total cross sections for electron scattering from other tetrachloride molecules: XCl4 where X=C, Si, Ge.

  • Toward Robust Pedestrian Detection With Data Augmentation
    • Sebastian Cygert
    • Andrzej Czyżewski
    2020 Pełny tekst IEEE Access

    In this article, the problem of creating a safe pedestrian detection model that can operate in the real world is tackled. While recent advances have led to significantly improved detection accuracy on various benchmarks, existing deep learning models are vulnerable to invisible to the human eye changes in the input image which raises concerns about its safety. A popular and simple technique for improving robustness is using data augmentation. In this work, the robustness of existing data augmentation techniques is evaluated to propose a new simple augmentation scheme where during training, an image is combined with a patch of a stylized version of that image. Evaluation of pedestrian detection models robustness and uncertainty calibration under naturally occurring corruption and in realistic cross-dataset evaluation setting is conducted to show that our proposed solution improves upon previous work. In this paper, the importance of testing the robustness of recognition models is emphasized and it shows a simple way to improve it, which is a step towards creating robust pedestrian and object detection models.

  • Towards a Lightweight Approach for the Evaluation of Requirements Engineering Impact on Other IT Project Areas
    • Aleksander Jarzębowicz
    • Katarzyna Poniatowska
    2020 Pełny tekst

    Requirements Engineering (RE) is recognized as one of the most important, but difficult areas of software engineering, with a significant impact on other areas of the IT project and its final outcome. The empirical studies investigating this impact are hard to conduct, mainly due to large effort required. It is thus difficult for researchers and even more for industry practitioners to make evidence-based evaluations, how decisions about RE (e.g. RE process improvements, RE techniques selection) translate into requirements quality and influence other project areas. We propose an idea of a lightweight approach, utilizing the popular tools adopted by numerous software companies, to enable such evaluation without an excessive effort. The proposal is illustrated with a pilot study, where the data from 6 industrial projects from a single organization was analyzed and 3 metrics regarding requirements quality, rework effort and testing were used to demonstrate the impact of different RE techniques applied among considered projects. We also discuss the factors important to enabling adoption of the proposed approach.

  • Towards Changes of Macro-Economic Structures in Middle Eastern Countries. Empirical Evidence for 1970–2018
    • Ewa Lechman
    • Radosław Ślosarski
    2020

    Middle East countries share a wide bundle of specific structural economic features and one of the latest is a high dependency of these economies on fossil fuels, which is quantitatively demonstrated through the share of oil and gas revenues in total export, but also in gross domestic product composition. This high economic dependency on natural resources on one hand has recently generated a material wealth of Middle Eastern countries which is demonstrated in a gross domestic product, but—on the other hand, contemporary global challenges such as price shocks on international commodity markets are calling for urgent diversification of national economies. This research aims to review key structural features of the economies of the six-member states of the Gulf Cooperation Council and changes in their macroeconomic structures between 1970-2018. It shows country-wise evidence, with respect to diversification of gross domestic product composition, identifying structural shifts between industry, service and agricultural sector. To provide more specific insight into the structure of national economies it examines time changes in oil rents (as a share of GDP), natural gas rents (as a share of GDP), fuel exports (share of merchandise exports). Finally, to verify the hypothesis that shifts in economic structure and GDP composition are accompanied by changes in sources of electricity production. Hence we additionally rely on data regarding sources of electricity production like coal, natural gas, oil, hydroelectric power plants (hydropower) and renewable sources (excluding hydroelectric but including geothermal, solar, tides, wind, biomass, and biofuels). Our methodological settings combine elementary descriptive statistics, time trends analysis, locally weighted polynomial smoothers for visual inspection of pair-wise correlations and panel regression models to capture statistical relationships between data examined. All macroeconomic data used in this research are exclusively extracted from World Development Indicators 2019.

  • Towards Extending Wikipedia with Bidirectional Links
    • Szymon Olewniczak
    • Tomasz Boiński
    • Julian Szymański
    2020 Pełny tekst

    In this paper, we present the results of our WikiLinks project which aims at extending current Wikipedia linkage mechanisms. Wikipedia has become recently one of the most important information sources on the Internet, which still is based on relatively simple linkage facilities. A WikiLinks system extends the Wikipedia with bidirectional links between fragments of articles. However, there were several attempts to introduce bidirectional fragment-fragment links to the Web, WikiLinks project is the first attempt to bring the new linkage mechanism directly to Wikipedia.

  • Towards Greater Citizen Participation in Financing Public Cultural Institutions—Legal Barriers and Proposed Solutions
    • Anna Modzelewska
    • Sebastian Skuza
    • Marta Szeluga-Romańska
    • Marta Materska-Samek
    2020 Pełny tekst Sustainability

    The paper contains a conceptual proposal that aims at indicating new models of participatory financing of cultural institutions as well as actions towards supporting culture. It presents results of a qualitative study in the form of action research, on identifying legal barriers of financing of cultural institutions in Poland. Additionally, it presents practical suggestions to the encountered problems that were worked out after discussions with cultural managers, taxpayers, and government administration decision-makers. The unique value of the study is a multidimensional and complex analysis of participatory financing of culture, citing varied sources and bearing a structured research procedure. We suggest a new discussion on establishing legal solutions for increasing of the funding or making the financing of cultural institutions more flexible, which appears to be particularly important in crisis times. All is presented as an original concept of participatory citizen-enterprise fiscal mechanism of supporting cultural institutions. We present a pragmatic solution to a problem of additional public support of culture, which can be put into practice parallel to state mechanisms, considering culture as a part of sustainable development.

  • Towards Improving Optimised Ship Weather Routing
    • Roberto Vettor
    • Joanna Szłapczyńska
    • Rafał Szłapczyński
    • Wojciech Tycholiz
    • Carlos Guedes Soares
    2020 Pełny tekst Polish Maritime Research

    The aim of the paper is to outline a project focusing on the development of a new type of ship weather routing solution with improved uncertainty handling, through better estimation of ship performance and responses to sea conditions. Ensemble forecasting is considered to take into account the uncertainty levels that are typical of operations in a stochastic environment. Increased accuracy of weather prediction is achieved through the assimilation of real-time data, measured by an on-board monitoring system. The proposed system will allow smooth integration of short-term Decision Support Systems for ship handling in dangerous or peculiar situations with long-term Decision Support Systems for weather routing. An appropriate user interface is also a critical part of the project and it will be implemented in a commercial Electronic Nautical Chart environment. A prototype of the full system will be installed and tested on a commercial vessel in regular operations and under real environmental conditions.

  • Towards Synthetic and Balanced Digital Government Benchmarking
    • Jaromir Durkiewicz
    • Tomasz Janowski
    2020 Pełny tekst

    Reliable benchmarking is essential for effective management of the government digitalization efforts. Existing benchmarking instruments generally fail to support this target. One problem is the diversity of instruments, resulting in a split image of digital progress and adding ambiguity to policy decisions. Another problem is disconnect in assessing progress between digital and traditional “analog” governance, lending support to a dangerous idea that countries can compensate for lack of progress in their governance systems by simply digitalizing them. This paper provides a path to addressing both problems by: aggregating relevant indicators of the World Economic Forum’s Network Readiness Index (NRI) to obtain a single synthetic measure of digital government, balancing this measure with progress in analog governance using World Bank’s Worldwide Governance Indicators (WGI), calculating new measures for the latest editions of NRI and WGI, and discussing results. Technically, the paper applies multidimensional linear ordering and factor analysis.

  • Toxoplasma gondii Recombinant antigen AMA1: Diagnostic Utility of Protein Fragments for the Detection of IgG and IgM Antibodies
    • Bartłomiej Ferra
    • Lucyna Holec-Gąsior
    • Justyna Gatkowska
    • Bożena Dziadek
    • Katarzyna Dzitko
    2020 Pełny tekst Pathogens

    Toxoplasma gondii is an important zoonotic protozoan that infects a wide variety of vertebrates as intermediate hosts. For this reason, the diagnosis of this disease is very important and requires continuous improvement. One possibility is to use recombinant antigens in serological tests. Apical membrane antigen 1 (AMA1), a protein located in specific secretory organelles (micronemes) of T. gondii, is very interesting in regard to its potential diagnostic utility. In the present study, we attempted to identify a fragment of the AMA1 protein with a high sensitivity and specificity for the serological diagnosis of human toxoplasmosis. The full-length AMA1 and two different fragments (AMA1N and AMA1C) were produced using an Escherichia coli expression system. After purification by metal affinity chromatography, recombinant proteins were tested for their utility as antigens in enzyme-linked immunosorbent assays (ELISAs) for the detection of IgG and IgM anti-T. gondii antibodies in human and mouse immune sera. Our data demonstrate that the full-length AMA1 recombinant antigen (corresponding to amino acid residues 67–569 of the native protein) has a better diagnostic potential than its N- or C-terminal fragments. This recombinant protein strongly interacts with specific anti-T. gondii IgG (99.4%) and IgM (80.0%) antibodies, and may be used for developing new tools for diagnostics of toxoplasmosis.

  • Toxoplasma gondii Recombinant Antigens in the Serodiagnosis of Toxoplasmosis in Domestic and Farm Animals
    • Bartłomiej Ferra
    • Lucyna Holec-Gąsior
    • Weronika Grąźlewska
    2020 Pełny tekst Animals

    Toxoplasmosis is caused by an intracellular protozoan, Toxoplasma gondii, and is a parasitic disease that occurs in all warm-blooded animals, including humans. Toxoplasmosis is one of the most common parasitic diseases of animals and results in reproductive losses. Toxoplasmosis in humans is usually caused by eating raw or undercooked meat or consuming dairy products containing the parasite. Diagnosis of toxoplasmosis is currently based on serological assays using native antigens to detect specific anti-T. gondii antibodies. Due to the high price, the available commercial agglutination assays are not suited to test a large number of animal serum samples. The recent development of proteomics elucidated the antigenic structure of T. gondii and enabled the development of various recombinant antigens that can be used in new, cheaper, and more effective diagnostic tools. Continuous development of scientific disciplines, such as molecular biology and genetic engineering, allows for the production of new recombinant antigens and provides the basis for new diagnostic tests for the detection of anti-T. gondii antibodies in animal serum samples.

  • Trace elements content of surface peat deposits in the Solovetsky Islands (White Sea)
    • Krystyna Kozioł
    • Joanna Korzeniowska
    • Daniel Okupny
    • Elżbieta Bezak-mazur
    • Stanisław Żurek
    2020 Pełny tekst Mires and Peat

    Peatlands form environmental archives of trace element deposition. In this regard they are particularly valuable for areas such as the Arctic, where regular pollution monitoring is either impossible or extremely costly. The aim of this study was to assess pollution in the Solovetsky Islands (65° 05' N, 35° 53' E) by examining the spatial variability in trace element content of the uppermost layer of peat, immediately below the surface layer of green vegetation. We evaluated Cr, Cd, Ni and Pb contents in samples taken from ombrotrophic (raised bog) and mesotrophic (transitional) mires and in different microtopographical settings (hummock/hollow), and calculated the following pollution indices: geoaccumulation index (Igeo), contamination factor (Cf) and degree of contamination (Cdeg). The contents of these elements were markedly lower in the Solovetsky Islands than reported from other parts of central and northern Europe. Depending on the pollution index considered, the studied peat samples could be classified as unpolluted to considerably polluted. The local spatial patterns showed the highest values of Cd in samples collected near the sea, while the highest contents of Cr and Ni were noted at sampling points located farther inland. Moreover, Cr and Pb concentrations were higher in raised bogs than in transitional mires, and this contrast was accentuated if raised bog was represented by hummocks alone. These patterns are consistent with the likely sources of Cr, Ni and Pb being atmospheric pollution; and with higher mobility of Cd in seawater, which periodically floods the transitional mires. Amongst the trace elements determined, the most consistent values across peat types and sampling locations were found for Ni, which could be successfully used for pollution monitoring even in transitional mires.

  • Transformacja Dworca Morskiego w Gdyni na Muzeum Emigracji
    • Robert Hirsch
    2020 Pełny tekst Ochrona Dziedzictwa Kulturowego

    Artykuł omawia współczesne adaptacje budynków historycznych w Polsce, określając dwa główne nurty: komercyjny i niekomercyjny. Jako przykład niekomercyjnej transformacji przedstawiony został przypadek modernistycznego Dworca Morskiego w Gdyni z lat 30. XX w. przekształconego na Muzeum Emigracji. Przedsięwzięcie zakończone uroczystym otwarciem muzeum w 2015 r. zyskało wiele przychylnych opinii i zostało laureatem w konkursie "Zabytek zadbany", organizowanym przez Generalnego Konserwatora Zabytków. Pomimo pozytywnych efektów tej transformacji, w artykule podjęto próbę krytycznej oceny tej inwestycji pod względem konserwatorskim.

  • Transient modeling in common DC link of power converters
    • A. Anuchin
    • G.l. Demidova
    • Ryszard Strzelecki
    • M.s. Yakovenko
    2020 Pełny tekst Science, Technology and Arts Research Journal

    Предмет исследования. Представлена математическая модель силовых преобразователей электропривода, питающихся от общего звена постоянного тока, на примере тяговых электроприводов карьерного самосвала БЕЛАЗ-90 мощностью 280 кВт. Модель выполнена в пакете MATLAB/Simulink. Новизна предложенной модели заключается в применении новой топологии силовой схемы для исследования работы двух инверторов, под- ключенных к одному звену постоянного тока. Представлена возможность исследования переходных процессов в распределенном звене постоянного тока с целью уменьшения пульсаций тока, как в конденсаторной батарее инверторов, так и в общем звене постоянного тока. Метод. В целях снижения пульсаций на аппаратном уровне предложен метод введения дополнительной индуктивности между конденсаторами инверторов. С этой же целью при широтно-импульсной модуляции на алгоритмическом уровне предложено введение фазового сдвига опор- ных сигналов двух параллельно работающих инверторов. Разработана математическая модель, позволяющая оценивать пульсации тока между инвертором и конденсатором звена постоянного тока и между конденсатором и источником питания. Основные результаты. Показано, что алгоритмический метод вдвое снижает пульсации тока между инвертором и конденсатором звена постоянного тока и до 10 раз снижает ток между конденсатором инвертора и источником питания. Практическая значимость. Предложенная модель может быть использована при проверке токовой нагрузки элементов силового преобразователя в процессе проектирования систем мно- годвигательного электропривода (станочные приводы, гибридные транспортные средства).

  • Transient States during Short-circuit in a Line Powered by UPS and its Impact on Earth Fault Loop Impedance Measurement and Power Quality
    • Jacek Katarzyński
    • Marek Olesz
    2020

    The short-circuit in a line powered by Uninterruptible Power Supply (UPS) during different UPS operation modes is presented in the article. The transient state condition related to the short-circuit in a line fed from double conversion On-line UPS is discussed in detail. The results of the measurements of earth fault loop impedance (FLI) in circuits powered by UPS with the instruments of various manufacturers are presented. The dispersion of the measurement results, depending on UPS operation mode and on the instrument test current value is observed. The uncertainty of FLI measurement in UPS-powered circuits is pointed out, and its impact on the power quality and the evaluation of effectiveness of protection against electric shock is explained.

  • Transport of paracetamol in swellable and relaxing polyurethane nanocomposite hydrogels
    • Marta Motke
    • Justyna Strankowska
    • Jerzy Kwela
    • Marek Józefowicz
    • Michał Strankowski
    2020 Pełny tekst POLYMER BULLETIN

    Polyurethane hydrogels are potentially attractive materials for biomedical applications. They are able to absorb large amount of water, biological fluids or active substances, and thus, they have potential to be used as absorbents or wound-healing dressings. They are also used for the controlled release of therapeutics because of their capacity to embed biologically active agents in their water-swollen network. The presence of organofillized montmorillonite (Cloisite® 30B) in polyurethane nanocomposite hydrogels remarkably improves the swelling capability, but on the other hand slows down the release process of an active substance from the matrix. The swelling of paracetamol solution by the nanocomposite matrix and the release process of this active substance from the hydrogel were investigated using gravimetric analysis and spectroscopic method. The kinetics of both these processes were accurately analyzed by the use of Korsmeyer–Peppas and modified Hopfenberg and Weibull models. In the present paper, three different nanocomposite systems with various amounts of Cloisite® 30B were studied. The results of these studies confirm beneficial impact of the nanosize effect on the drug diffusion processes in polyurethane nanocomposite hydrogels.

  • Transverse surface waves on a cylindrical surface with coating
    • Victor Eremeev
    • Giuseppe Rosi
    • Salah Naili
    2020 Pełny tekst INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE

    We discuss the propagation of transverse surface waves that are so-called whispering-gallery waves along a surface of an elastic cylinder with coating. The coating is modelled in the framework of linearized Gurtin–Murdoch surface elasticity. Other interpretations of the surface shear modulus are given and relations to so-called stiff interface and stiff skin model are discussed. The dispersion relations are obtained and analyzed.

  • Trendy rozwojowe współczesnej telekomunikacji i wynikające z tego zagrożenia
    • Ryszard Katulski
    2020 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Telekomunikacja to dziedzina wiedzy i techniki, której przeznaczeniem jest przenoszenie informacji, z założenia z dowolnego miejsca do innego dowolnego miejsca nie tylko na kuli ziemskiej, lecz także w dostępnej nam przestrzeni. Walorem szczególnym tego jest telekomunikacja radiowa, która umożliwia tworzenie połączeń telekomunikacyjnych w sposób bezprzewodowy, za pomocą zjawiska fali radiowej, które – jak wiadomo – ma naturę pola elektromagnetycznego. Pozwala to przekazywać informacje od nadawców do odbiorców znajdujących się w stanie ruchu, a więc potencjalnie obsługiwać każdego użytkownika wyposażonego w tzw. terminal końcowy. Przy czym jest to możliwe w każdym czasie i w dowolnym miejscu. Jak widać, znaczenie telekomunikacji we współczesnym świecie trudno jest przecenić.

  • Tribological Properties of Ni-P/Si3N4 Nanocomposite Layers Deposited by Chemical Reduction Method on Aluminum Alloy AW-7075
    • Kazimierz Czapczyk
    2020 Pełny tekst Materials

    The article presents the results of tribological tests of Ni-P/Si3N4 nanocomposite and Ni-P nickel layers deposited on the AW-7075 aluminum alloy by chemical reduction method, and the AW-7075 alloy without coating. Nanocomposite layers were produced using Si3N4 siliconnitride in the form of a polydisperse powder whose particle sizes ranged from 20 to 25 nm. The influence of the content of the dispersion phase layer material on the abrasive wear, which was determined as the “ball on disc” method, was analyzed. Surface topography was examined by the contact method using a profilometer. The purpose of introducing Si3N4 particles into the Ni-P layer was to increase the wear resistance of AW-7075 aluminum alloy parts with an embedded nanocomposite coating. Based on the obtained test results, it was found that the Ni-P/Si3N4 layers are more resistant to wear than the Ni-P layers and the AW-7075 alloy layers, and are a good barrier against abrasive wear at various loads and environmental conditions.

  • Trimethylamine N-oxide and the reverse cholesterol transport in cardiovascular disease: a cross-sectional study
    • Laura Bordoni
    • Joanna J. Samulak
    • Angelika K. Sawicka
    • Iwona Pelikant-Malecka
    • Adrianna Radulska
    • Lukasz Lewicki
    • Leszek Kalinowski
    • Rosita Gabbianelli
    • Robert Olek
    2020 Pełny tekst Scientific Reports

    The early atherosclerotic lesions develop by the accumulation of arterial foam cells derived mainly from cholesterol-loaded macrophages. Therefore, cholesterol and cholesteryl ester transfer protein (CETP) have been considered as causative in atherosclerosis. Moreover, recent studies indicate the role of trimethylamine N-oxide (TMAO) in development of cardiovascular disease (CVD). The current study aimed to investigate the association between TMAO and CETP polymorphisms (rs12720922 and rs247616), previously identified as a genetic determinant of circulating CETP, in a population of coronary artery disease (CAD) patients (n = 394) and control subjects (n = 153). We also considered age, sex, trimethylamine (TMA) levels and glomerular filtration rate (GFR) as other factors that can potentially play a role in this complex picture. We found no association of TMAO with genetically determined CETP in a population of CAD patients and control subjects. Moreover, we noticed no differences between CAD patients and control subjects in plasma TMAO levels. On the contrary, lower levels of TMA in CAD patients respect to controls were observed. Our results indicated a significant correlation between GFR and TMAO, but not TMA. The debate whether TMAO can be a harmful, diagnostic or protective marker in CVD needs to be continued.

  • Tripped at the Finishing Line: The Åland Islands Internet Voting Project
    • David Duenas Cid
    • Iuliia Krivonosova
    • Radu Serrano
    • Marlon Freire
    • Robert Krimmer
    • David Duenas-Cid
    2020 Pełny tekst

    The Åland Islands spent years preparing an internet voting system, to be implemented for the first time in October 2019 for Parliamentary Elections. Despite this, the project was canceled the evening before the expected release date. In this paper, we explore the causes of this failure using a two-pronged approach including Information System failure perspectives and the approach to e-voting Mirabilis, focusing on organizational elements which provoked the decision not to use the system.

  • Trouble in Paradise? Barriers to Open Innovation in Regional Clusters in the Era of the 4th Industrial Revolution
    • Marita Mcphillips
    2020 Pełny tekst Journal of Open Innovation: Technology, Market, and Complexity

    The purpose of this paper is to provide an insight into the barriers faced by clusters as open innovation intermediaries. Literature review and an empirical study were performed, involving a nation-wide survey, case studies, and in-depth interviews with cluster actors involved in open innovation activities. This article conceptually links open innovation and clusters in the context of the fourth industrial revolution, empirically identifies barriers hindering open innovation in clusters, and indicates factors that might affect the open innovation processes in networked ecosystems. The findings confirm that the perception of barriers hindering open innovation in clusters differs between clusters already implementing open innovation and those which are still not active in this area. The findings contribute to a comprehensive understanding of the potential roles of clusters as open innovation intermediaries in the context of transitioning economies. With clusters playing a role in open innovation intermediary, public support at cluster level could increase openness to cooperation not only for member companies, but all participants in the regional innovation ecosystem.

  • Trust-Based Model for the Assessment of the Uncertainty of Measurements in Hybrid IoT Networks
    • Piotr Cofta
    • Cezary Orłowski
    • Jacek Lebiedź
    2020 Pełny tekst SENSORS

    The aim of this paper is to introduce a NUT model (NUT: network-uncertainty-trust) that aids the decrease of the uncertainty of measurements in autonomous hybrid Internet of Things sensor networks. The problem of uncertainty in such networks is a consequence of various operating conditions and varied quality of measurement nodes, making statistical approach less successful. This paper presents a model for decreasing the uncertainty through the use of socially inspired metaphors of reputation, trust, and confidence that are the untapped latent information. The model described in the paper shows how the individual reputation of each node can be assessed on the basis of opinions provided by other nodes of the hybrid measurement network, and that this method allows to assess the extent of uncertainty the node introduces to the network. This, in turn, allows nodes of low uncertainty to have a greater impact on the reconstruction of values. The verification of the model, as well as examples of its applicability to air quality measurements are presented as well. Simulations demonstrate that the use of the model can decrease the uncertainty by up to 55% while using the EWMA (exponentially weighted moving average) algorithm, as compared to the reference one.

  • Tuning the extraction properties of ionogel-coated Solid-phase microextraction fibers based on the solvation properties of the ionic liquids
    • Kateryna Yavir
    • Karolina Konieczna
    • Łukasz Marcinkowski
    • Adam Kloskowski
    2020 SEPARATION AND PURIFICATION TECHNOLOGY

    A silica-based network was used to immobilize ionic liquid-based ionogels and applied as a fiber coating forsolid-phase microextraction (SPME). The ionogels were prepared by a sol–gel process, using two ionic liquids,triethylsulfonium bis(trifluoromethylsulfonyl)imide ([Set3][TFSI]) and 1-butyl-1-methylpiperidinium bis(tri-fluoromethylsulfonyl)imide ([C4C1Pip][TFSI]), as well as their equimolar mixture. Methyltrimethoxysilane wasused as the sol–gel precursor, and trifluoroacetic acid as a reaction catalyst.The fabricated ionogel fibers were evaluated as sorbent coating in headspace SPME combined with gaschromatography with barrier ionization discharge detection for volatile organic compounds (VOCs). The fibersshowed a high affinity to aromatic VOCs, yielding good sensitivity and precision. Then, the developed methodwas applied to the analysis of aqueous samples.During the study, the main extraction parameters, i.e., salt concentration, extraction time, and temperature,were optimized for maximum fiber sorption and to maximize the enrichment factors. The average limits ofdetection were found to be 0.15 μg L−1, 0.40 μg L−1, and 0.07 μg L−1, and the enrichment factors were in the25700–61000, 33200–84700, and 29100–96500 ranges for [Set3], [C4C1Pip] and [Set3/C4C1Pip], respectively.The single fiber and fiber-to-fiber reproducibilities were below 11.2% and 30.6%, respectively. The results of thiswork suggest the possibility of fabricating selected extractants based on the physicochemical properties of theionic liquids and target analytes.

  • Two kinds of oxygen vacancies in lithium titaniate doped with copper as detected by EPR
    • Marcin Łapiński
    • Lidia Piekara-Sady
    • Robert Kozioł
    • Wojciech Sadowski
    • Barbara Kościelska
    2020 SOLID STATE SCIENCES

    Lithium titanate (Li1+xTi2-xO4) doped with Cu2+ ions was synthesized by sol-gel processing method. The structure and morphology are characterized by X-ray Diffraction (XRD), X-ray Photoemission Spectroscopy (XPS), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). Spin Hamiltonian parameters describing Zeeman and hyperfine interaction for 63Cu2+ ions were obtained from EPR spectra simulations. The spectra are characteristic for (Cu-VO)0 close-associate pairs consisting of copper replacing Ti4+ ion and an adjacent doubly ionized oxygen vacancy. These oxygen vacancies serve as charge compensators for the substituting copper ions. However, there are additional narrow EPR signals at g = 2.004 in all samples, including the sample of LiTi2O4 without dopant. These signals are ascribed to single-electron trapped oxygen vacancies VO●. Superconductivity was not confirmed down to 4.2 K by magnetic measurements in all samples studied.

  • Tworzenie wartości wspólnej w uniwersytecie
    • Elżbieta Karwowska
    2020

    Problemem badawczym jest brak definicji pojęcia i modelu teoretycznego tworzenia wartości wspólnej w uniwersytecie, który jest przeszkodą dla przeprowadzenia dyskursu naukowego zmierzającego do zbadania jej możliwości oraz zasadności. Lepsze zrozumienie możliwości i zasadności tworzenia wartości wspólnej w uniwersytecie stworzy zaś nową przestrzeń do opracowania narzędzi wspomagających rozwijanie społecznej odpowiedzialności uniwersytetu. Celem rozprawy jest zdefiniowanie pojęcia oraz zbadanie możliwości i zasadności tworzenia wartości wspólnej w uniwersytecie. Aby osiągnąć przyjęty cel rozprawy, w pierwszej kolejności rozpoznano, jak rozumiane było dotąd pojęcie CSV w kontekście społecznej odpowiedzialności uniwersytetu. Następnie zaproponowano model tworzenia wartości wspólnej w uniwersytecie (CSVU, Creating Shared Value by the University) oraz zdefiniowano to pojęcie w oparciu o zaproponowany model. Kolejnym krokiem było zbadanie możliwości oraz zasadności tworzenia wartości wspólnej w uniwersytecie z perspektywy uczelni oraz z perspektywy jej otoczenia: administracji publicznej oraz biznesu. Eksploracja możliwości i zasadności CSVU z perspektywy uczelni nastąpiła za pomocą analizy tematycznej danych jakościowych zebranych za pomocą wywiadów z reprezentantami uczelni. Możliwość i zasadność CSVU z perspektywy administracji publicznej zbadano na podstawie analizy dokumentów i aktów prawnych, regulujących społeczną odpowiedzialność uczelni i ich relacje z otoczeniem społecznym i gospodarczym. Możliwość i zasadność CSVU z perspektywy biznesu zbadano zaś na podstawie analizy raportów z badań wtórnych, dotyczących opinii przedsiębiorców na temat współpracy z uczelniami. Rezultatem przeprowadzonych analiz jakościowych jest zidentyfikowanie szeregu uwarunkowań, a także szans i zagrożeń, które wpływają na możliwość i zasadność tworzenia wartości wspólnej w uniwersytecie. Wyniki przeprowadzonych badań mają również walor utylitarny, dzięki rekomendacjom w formie listy, która stanowi praktyczne wytyczne dla uniwersytetów, zainteresowanych tworzeniem wartości wspólnej.

  • Two-step mechanism of J-domain action in driving Hsp70 function
    • Bartlomiej Tomiczek
    • Wojciech Delewski
    • Łukasz Nierzwicki
    • Milena Stolarska
    • Igor Grochowina
    • Brenda Schilke
    • Rafal Dutkiewicz
    • Marta A. Uzarska
    • Szymon Ciesielski
    • Jacek Czub
    • Elizabeth Craig
    • Jaroslaw Marszalek
    2020 Pełny tekst PLoS Computational Biology

    J-domain proteins (JDPs), obligatory Hsp70 cochaperones, play critical roles in protein homeostasis. They promote key allosteric transitions that stabilize Hsp70 interaction with substrate polypeptides upon hydrolysis of its bound ATP. Although a recent crystal structure revealed the physical mode of interaction between a J-domain and an Hsp70, the structural and dynamic consequences of J-domain action once bound and how Hsp70s discriminate among its multiple JDP partners remain enigmatic. We combined free energy simulations, biochemical assays and evolutionary analyses to address these issues. Our results indicate that the invariant aspartate of the J-domain perturbs a conserved intramolecular Hsp70 network of contacts that crosses domains. This perturbation leads to destabilization of the domain-domain interface—thereby promoting the allosteric transition that triggers ATP hydrolysis. While this mechanistic step is driven by conserved residues, evolutionarily variable residues are key to initial JDP/Hsp70 recognition—via electrostatic interactions between oppositely charged surfaces. We speculate that these variable residues allow an Hsp70 to discriminate amongst JDP partners, as many of them have coevolved. Together, our data points to a two-step mode of J-domain action, a recognition stage followed by a mechanistic stage.

  • Tynki - wykonywanie i pielęgnacja
    • Maciej Niedostatkiewicz
    • Tomasz Majewski
    2020 Pełny tekst Inżynier Budownictwa

    W artykule przedstawiono podstawowe wymagania jakie powinny być zachowane podczas realizacji oraz późniejszej eksploatacji tynków tak aby jak najdłużej zachowac je w stanie wysokiej sprawności technicznej

  • Udział Biblioteki Politechniki Gdańskiej w procesie umiędzynarodowiania uczelni
    • Urszula Szybowska
    2020 Pełny tekst Pismo PG

    Umiędzynarodowienie szkolnictwa wyższego definiowane jest zasadniczo jako podejmowanie studiów na zagranicznych uczelniach oraz udział w międzynarodowych projektach badawczych i szkoleniowych. Umiędzynarodowienie szkół wyższych jest jednym z elementarnych wskaźników, które określają dziś rozwój nauki i szkolnictwa wyższego. Biblioteka PG na różnych polach wspiera uczelnię w procesie internacjonalizacji. Strategia rozwoju usług Biblioteki PG funkcjonującej w międzynarodowym środowisku opiera się zasadniczo na trzech filarach: dostosowaniu swoich zbiorów i usług do potrzeb użytkowników zagranicznych, uczestniczeniu w programie Erasmus+ oraz dynamicznym rozwijaniu współpracy z organizacjami międzynarodowymi.

  • Udział w wystawie zbiorowej WETWARE: PROLIFERACJA I PRZECZUCIE
    • Patryk Różycki
    2020

    „WETWARE: PROLIFERACJA I PRZECZUCIE” Wystawa w Instytucie Cybernetyki Sztuki Dzieła sztuki w ich materialnym aspekcie możemy postrzegać jako nośniki informacji programujące i stymulujące przebieg procesów społecznych. Wystawa proponuje namysł nad dziełami sztuki i aktywnościami artystycznymi poprzez pryzmat terminu WETWARE – rozrostu struktur biologicznych i fizycznych umożliwiających przejawianie się procesów mentalnych. Psycholog Karl H. Pribram ukuł termin „wetware”1, dla podkreślenia specyfiki biologicznej w zakresie zdolności przenoszenia poprzez struktury biologiczne (neurony) różnego rodzaju informacji. Marek Rogulski artystki i artyści: Marcin Bożek, Marta Branicka, Flora Ćwirko + Jan Maurycy Adamski, Jowan Czerkas, Urszula Dulewicz, Dorota Grubba Thiede + Danuta Ćwirko Godycka, Tomasz Kopcewicz, Marta Koniarska, Maria Krupa, Monika Krygier + Stefan Krygier + Włodzimierz Pietrzyk, Przemysław Kryszk, Ryszard Ługowski, Krzysztof Malec, Anna Malinowska, Andrzej Egon Fietke Miastkowski, Piotr Tadeusz Mosur, Mateusz Pęk, Katarzyna Podpora, Marek Rogulski, Magdalena Rosman, Patryk Różycki, Wojtek Sosnowski, Urszula Śliz, Xenia Uranova, Marcelo Zammenhoff, Sofia Żezmer.

  • Układy dynamiczne w analizie zachowania się geosyntetyków w kolejowych konstrukcjach inżynierskich
    • Eligiusz Mieloszyk
    • Anita Milewska
    • Sławomir Grulkowski
    2020 Pełny tekst Przegląd Komunikacyjny

    W analizie współpracy geosyntetyków z elementami konstrukcji inżynierskiej możemy je traktować jako membrany sprężyste lub powłoki posadowione na różnych rodzajach podłoża. Modelowanie układu rzeczywistego oznacza jego idealizację pod kątem uwzględnienia tych cech ośrodka i jego elementów, które wydają się najistotniejsze z punktu widzenia analizowanego problemu. Zbudowany zostanie model fizyczny, a następnie matematyczny przedstawiony w postaci uogólnionego układu dynamicznego. W tym opisie wykorzystuje się różne operatory. Prowadzą one do układów ciągłych o parametrach rozłożonych. Rozpoczynając od opisu z wykorzystaniem układów dynamicznych ciągłych można przejść do układów dynamicznych dyskretnych. Pozwala na to teoria uogólnionych układów dynamicznych, poprzez wykorzystanie innych operatorów. Takie podejście umożliwia prowadzenie analizy problemu z wykorzystaniem sygnałów ciągłych i dyskretnych. Otrzymane wyniki pozwalają też wyznaczać odpowiedzi analizowanych układów metodami analitycznymi, numerycznymi lub hybrydowymi.

  • Ultrafast degradation of brilliant cresyl blue under hydrodynamic cavitation based advanced oxidation processes (AOPs)
    • Elvana Cako
    • Kumaravel Dinesh Gunasekaran
    • Reza Darvishi Cheshmeh Soltani
    • Grzegorz Boczkaj
    2020 Pełny tekst Water Resources and Industry

    The study highlights effectiveness of hydrodynamic cavitation (HC) in the degradation of effluents polluted by Brilliant Cresyl Blue (BCB) dye. Optimal process parameters were cavitation number 0.27, inlet pressure 1.70 bar, temperature 20 °C and pH 7. The efficiency of HC was investigated in combination with other advanced oxidation processes, including the addition of external oxidants (hydrogen peroxide, ozone, and sodium persulfate) and photooxidation. A detailed investigation of reactive radical species present in the system is also presented. Hybrid processes based on HC revealed the highest synergism. Finally, ultrafast degradation of target oxazine dye (decolorization efficiency of 100%) within the short treatment time of 1 min was developed. The most effective process was a combination of hydrodynamic cavitation and ozonation with a synergistic coefficient of 1.84 and electrical energy per order EEO of 0.03 kWh m⁻³ order⁻¹. The presented solution is ready to be implemented as technology for industrial practice.

  • Ultrasound assisted solvent extraction of porous membrane-packed samples followed by liquid chromatography-tandem mass spectrometry for determination of BADGE, BFDGE and their derivatives in packed vegetables
    • Natalia Szczepańska
    • Paweł Kubica
    • Justyna Płotka-Wasylka
    • Błażej Kudłak
    • Jacek Namieśnik
    2020 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    The problem of the presence of trace organic pollutants in food is of growing importance due to increasing awareness about their impact on newborns, infants and adults of reproductive age. Despite the fact that packaged food products offer many advantages, packaging can be a source of contamination for stored food. Thus, monitoring such pollution in food is of high importance. In this work, a novel methodology based on the solvent extraction of porous membrane-packed samples followed by liquid chromatography-tandem mass spectrometry was applied for the determination of bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE) and their derivatives in packed vegetables. Several parameters of the extraction process were optimized, including the volume and type of extraction solvent as well as the sonication time. Due to advantages such as simplicity of use, short analysis time, and a reduction in the required amount solvent, the developed procedure can be considered green. In addition, the developed methodology was characterized by good validation parameters. Limit if quantitation (LOQ) was found to be in the range of 0.8 to 1.5 ng/g. The obtained recoveries varied from 78.3% to 111.2%. The repeatability of the extraction ranged between 0.6% and 5.8% (RSD). The proposed method was successfully applied to determine the presence of BADGE, BFDGE and their derivative compounds in the vegetable samples stored in different types of containers. The obtained data indicate that the majority of investigated samples were contaminated by chlorinated and hydroxyl derivatives of BADGE.

  • Ultrasound assisted synthesis of 3-alkynyl substituted 2-chloroquinoxaline derivatives: Their in silico assessment as potential ligands for N-protein of SARS-CoV-2
    • Shaik Shahinshavali
    • Kazi Hossain
    • Abbaraju Venkata Durga Nagendra Kumar
    • Alugubelli Gopi Reddy
    • Deepti Kolli
    • Ali Nakhi
    • Mandava Venkata Basaveswara Rao
    • Manojit Pal
    2020 TETRAHEDRON LETTERS

    In view of recent global pandemic the 3-alkynyl substituted 2-chloroquinoxaline framework has been explored as a potential template for the design of molecules targeting COVID-19. Initial in silico studies of representative compounds to assess their binding affinities via docking into the N-terminal RNA-binding domain (NTD) of N-protein of SARS-CoV-2 prompted further study of these molecules. Thus building of a small library of molecules based on the said template became essential for this purpose. Accordingly, a convenient and environmentally safer method has been developed for the rapid synthesis of 3-alkynyl substituted 2-chloroquinoxaline derivatives under Cu-catalysis assisted by ultrasound. This simple and straightforward method involved the coupling of 2,3-dichloroquinoxaline with commercially available terminal alkynes in the presence of CuI, PPh3 and K2CO3 in PEG-400. Further in silico studies revealed some remarkable observations and established a virtual SAR (Structure Activity Relationship) within the series. Three compounds appeared as potential agents for further studies.

  • Ultrasound-assisted heterogeneous activation of persulfate and peroxymonosulfate by asphaltenes for the degradation of BTEX in water
    • Kirill Fedorov
    • Maksymilian Plata-Gryl
    • Javed Khan
    • Grzegorz Boczkaj
    2020 Pełny tekst JOURNAL OF HAZARDOUS MATERIALS

    This study investigated – for the first time - the simultaneous degradation of benzene, toluene, ethylbenzene and o-xylene (BTEX) by persulfate (PS) and peroxymonosulfate (PMS) activated by asphaltenes (Asph) under ultrasound (US) irradiation. Advantageous properties such as high thermal stability, low production cost and extensive availability make asphaltenes as an appealing carbonaceous material for heterogeneous catalysis. The application of asphaltenes in PS/US increased the degradation of BTEXs from 31%, 34%, 35%, 32% to 78%, 94%, 98% and 98%, while the removal of these compounds in PMS/US system was improved from 26%, 27%, 24%, 20% to 76%, 91%, 97%, 97%, respectively. PS and PMS activation followed a typical sulfate-radical based advanced oxidation processes. In terms of activation of PS and PMS, the particles of asphaltenes intensified formation of reactive radicals by creating additional centers of cavitational events. Moreover, owing to π–π stacking interaction between asphaltenes and sp2-hybridized systems of BTEX, the contaminants undergo adsorption on the surface of asphaltenes and subsequent oxidation by formed radicals. The radical route of BTEX degradation in both PS/US/Asph and PMS/US/Asph systems was mainly contributed by sulfate (SO4•−) and hydroxyl radicals (HO•) and coexisting superoxide radical anions (O2•−) played a minor role.

  • Ultrastructural analysis of the submandibular sialoliths: Raman spectroscopy and electron back-scatter studies
    • Dmitry Tretiakov
    • Andrzej Skorek
    • Jacek Ryl
    • Joanna Wysocka
    • Kazimierz Darowicki
    • Dmitry Tretiakow
    2020 Pełny tekst ULTRASTRUCTURAL PATHOLOGY

    The aim of work was the epidemiological analysis of the occurrence of sialolithiasis of the submandibular gland in adults and the evaluation of the ultrastructure of salivary stones. The study sample consisted of 44 sialoliths. Analysis of the structure and chemical composition of sialoliths was performed using a Scanning Electron Microscope and Raman Spectroscopy. Comparing our results with the literature we can say that the epidemiology of sialolithiasis has not changed significantly over the past 50 years. A wide variety of sialoliths structure was observed. In 75% (33) cases a layered structure of salivary stones was observed, while in 25% (11) – homogeneous structure. The various distribution of organic and inorganic components was observed among all the analyzed sialoliths. Raman spectroscopy allows for preliminary analysis of the sialoliths structure with only a qualitative assessment of their composition, which significantly reduces the research value of this method. The presence of organic and inorganic compounds in the core and inner layers of the salivary glands stones confirms 2 basic theories of the formation of sialoliths: inflammation and deposition of the inorganic component as a result of disruption of saliva flow in the salivary glands.

  • Uncertainty of mass flow measurement using centric and eccentric orifice for Reynolds number in the range 10,000 ≤ Re ≤ 20,000
    • Anna Golijanek-Jędrzejczyk
    • Andrzej Mrowiec
    • Robert Hanus
    • Marcin Zych
    • Dariusz Świsulski
    2020 Pełny tekst MEASUREMENT

    The article analyses the impact of the Reynolds number on the estimated uncertainty of the mass flow rate measurement using an orifice plate. The objects of the research were two types of orifices: centric (ISA) and eccentric, with the diameter ratio β = 0.5. Studies were performed by Monte Carlo simulation and experiments for Reynolds numbers in the range 10,000 ≤ Re ≤ 20,000. The obtained results have shown that for both orifice types, the results obtained from the experiments and from the Monte Carlo simulation are similar. The nature of changes in the expanded uncertainty of the flow measurement is very similar for each type. For the both types of orifices, the value of the expanded uncertainty of the flow measurement increases linearly with the increasing Reynolds number.

  • Underfrequency Load Shedding: An Innovative Algorithm Based on Fuzzy Logic
    • Robert Małkowski
    • Janusz Nieznański
    2020 Pełny tekst ENERGIES

    In contemporary power systems, the load shedding schemes are typically based on disconnecting a pre-specified amount of load after the frequency drops below a predetermined value. The actual conditions at the time of disturbance may largely dier from the assumptions, which can lead to non-optimal or ineective operation of the load shedding scheme. For many years, increasing the eectiveness of the underfrequency load shedding (UFLS) schemes has been the subject of research around the world. Unfortunately, the proposed solutions often require costly technical resources and/or large amounts of real-time data monitoring. This paper puts forth an UFLS scheme characterized by increased eectiveness in the case of large disturbances and reduced disconnected power in the case of small and medium disturbances compared to the conventional load-shedding solutions. These advantages are achieved by replacing time-consuming consecutive load dropping with the simultaneous load dropping mechanism and by replacing ineective fixed-frequency activation thresholds independent of the state of the system with implicit adaptive thresholds based on fuzzy logic computations. The proposed algorithm does not require complex and costly technical solutions. The performance of the proposed scheme was validated using multivariate computer simulations. Selected test results are included in this paper.

  • Understanding the formation of metastable furan dication in collisions with ions
    • Ewa Erdmann
    • Suvasthika Indrajith
    • Jacopo Chiarinelli
    • Sergio Díaz-Tendero
    • Nestor F. Aguirre
    • Manuel Alcamí
    • Alicja Domaracka
    • Patrick Rousseau
    • Bernd Alan Huber
    • Paola Bolognesi
    • Lorenzo Avaldi
    • Marta Łabuda
    2020 Pełny tekst Journal of Physics : Conference Series

    This work relies on complementary theoretical and experimental studies of the processes induced by ion-furan collisions. Results of the Molecular Dynamics simulations and exploration of the energy profiles combined with coincidence mass spectrometry provide complete picture of the fragmentation of furan dication.

  • Underwater in situ local heat treatment by additional stitches for improving the weldability of steel
    • Jacek Tomków
    • Anna Janeczek
    2020 Pełny tekst Applied Sciences-Basel

    In this paper the influence of in situ local heat treatment performed by additional stitches on the weldability of high-strength low-alloy (HSLA) S355J2C+N steel was tested. The investigated steel is characterized by high susceptibility to cold cracking. It is necessary to find a method to improve the quality of welded joints. The local heat treatment was applied as an eect of bead-on plate welding made on the face of a Tekken test joint. The specimens were made by the use of covered electrodes in the water environment. For testing weldability, Tekken test specimens were made. Then, the dierent number of the pad welds with dierent overlapping were laid on the face of the tested welds. Non-destructive (NDT) visual and penetrant tests were undertaken. During the NDT, imperfections like shape mistakes and spatters were found. Then, metallographic macro- and microscopic testing were performed. The macroscopic observations proved that water environment can generate imperfections like cracking and pores. However, for specimens with additional stitches the number of imperfections decreased. Microscopic tests proved that the proposed technique aected the structure of the heat-aected zone (HAZ). The specimens without the application of additional stitches are characterized by brittle bainitic and martensitic structure. Specimens, in which the additional stitches were applied, contain tempered martensite, fine ferrite and fine pearlite in their HAZ. It was also observed that the number of cracks decreased for in situ local heat-treatment specimens. The final step was Vickers HV10 hardness measurement. These measurements confirmed previous results. The heat from additional stitches aected the steel by significantly decreasing the hardness by 80–100 HV10. The results of experiments showed that the heat from pad welds provided microstructural changes in heat-aected zones and a decrease in the susceptibility to cold cracking, which results in improvement in the weldability of HSLA steel in wet welding conditions.

  • Underwater Local Cavity Welding of S460N Steel
    • Jacek Tomków
    • Anna Janeczek
    • Grzegorz Rogalski
    • Adrian Wolski
    2020 Pełny tekst Materials

    In this paper, a comparison of the mechanical properties of high-strength low-alloy S460Nsteel welded joints is presented. The welded joints were made by the gas metal arc welding (GMAW)process in the air environment and water, by the local cavity welding method. Welded joints were testedfollowing the EN ISO 15614-1:2017 standard. After welding, the non-destructive—visual, penetrant,radiographic, and ultrasonic (phased array) tests were performed. In the next step, the destructive tests,as static tensile-, bending-, impact- metallographic (macroscopic and microscopic) tests, and VickersHV10 measurements were made. The influence of weld porosity on the mechanical properties of thetested joints was also assessed. The performed tests showed that the tensile strength of the jointsmanufactured in water (567 MPa) could be similar to the air welded joint (570 MPa). The standarddeviations from the measurements were—47 MPa in water and 33 MPa in the air. However, it was alsostated that in the case of a complex state of stress, for example, bending, torsional and tensile stresses,the welding imperfections (e.g., pores) significantly decrease the properties of the welded joint.In areas characterized by porosity the tensile strength decreased to 503 MPa. Significant differenceswere observed for bending tests. During the bending of the underwater welded joint, a smallerbending angle broke the specimen than was the case during the air welded joint bending. Also,the toughness and hardness of joints obtained in both environments were different. The minimumtoughness for specimens welded in water was 49 J (in the area characterized by high porosity) and inthe air it was 125 J (with a standard deviation of 23 J). The hardness in the heat-affected zone (HAZ)for the underwater joint in the non-tempered area was above 400 HV10 (with a standard deviation of37 HV10) and for the air joint below 300 HV10 (with a standard deviation of 17 HV10). The performedinvestigations showed the behavior of S460N steel, which is characterized by a high value of carbonequivalent (CeIIW) 0.464%, during local cavity welding.

  • Underwater Navigation Ssystem Based on Doppler Shift – Measurements and Error Estimations
    • Zawisza Ostrowski
    • Roman Salamon
    • Iwona Kochańska
    • Jacek Marszal
    2020 Pełny tekst Polish Maritime Research

    A new acoustic navigation system was developed to determine the position and speed of moving underwater objects such as divers and underwater vehicles. The path of an object and its speed were determined by the Doppler shifts of acoustic signals emitted by a transmitter placed on the object and received by four hydrophones installed at the periphery of the monitored body of water. The position and speed measurements were affected by errors mainly caused by acoustic reflections (returns) from the water body boundaries and surface reverberations. This paper discusses the source of the disturbances with the results of a simulation test and experimental measurements. It was demonstrated that the magnitude of the errors could be acceptable in most of the potential applications of the acoustic navigation system.

  • Unidirectional DC/DC Converter with Voltage Inverter for Fast Charging of Electric Vehicle Batteries
    • Jerzy, Ryszard Szymanski
    • Marta Żurek-mortka
    • Daniel Wojciechowski
    • Nikolai Poliakov
    2020 Pełny tekst ENERGIES

    The paper proposes the adaptation of the industrial plant’s power network to supply electric vehicle (EV) fast-charging converters (above 300 kW) using renewable energy sources (RESs). A 600 V DC microgrid was used to supply energy from RESs for the needs of variable speed motor drives and charging of EV batteries. It has been shown that it is possible to support the supply of drive voltage frequency converters (VFCs) and charging of EV batteries converters with renewable energy from a 600 V DC microgrid, which improves the power quality indicators in the power system. The possibility of implementing the fast EV batteries charging station to the industrial plant’s power system in such a way that the system energy demand is not increased has also been shown. The EV battery charging station using the drive converter has been presented, as well as the results of simulation and laboratory tests of the proposed solution.