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Publikacje z roku 2019

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  • Potyczki algorytmiczne, czyli Alicja i Bogdan w różnych sytuacjach. Alicja i Bogdan w krainie czarów
    • Marek Kubale
    2019 Pismo PG

    Wprowadzono w zagadnienia NP-zupełności na przykładzie problemu Suma Podzbioru

  • Potyczki algorytmiczne, czyli Alicja i Bogdan w różnych sytuacjach. Alicja i Bogdan w kuchni
    • Marek Kubale
    2019 Pismo PG

    W pierwszym odcinku serii zagadek algorytmicznych przedstawiamy problem podziału pizzy oraz grę naleśnikową

  • Potyczki algorytmiczne, czyli Alicja i Bogdan w różnych sytuacjach. Alicja i Bogdan w samochodzie
    • Marek Kubale
    2019 Pismo PG

    Przedstawiono dwie zagadki algorytmiczne ilustujące przeszukiwanie wyczerpujące

  • Potyczki algorytmiczne, czyli Alicja i Bogdan w różnych sytuacjach. Alicja i Bogdan wśród ludożerców
    • Marek Kubale
    2019 Pismo PG

    Wprowadzono do zagadnień złożoności czasowej i pamięciowej

  • Potyczki algorytmiczne, czyli Alicja i Bogdan w różnych sytuacjach. Alicja i Bogdan wyprawiają wesele
    • Marek Kubale
    2019 Pismo PG

    Wprowadzono w zagadnienie przeglądania z dwoma wartownikami

  • Powder metallurgy of the porous Ti-13Nb-13Zr alloy of different powder grain size
    • Tomasz Seramak
    • Andrzej Zieliński
    • Waldemar Serbiński
    • Katarzyna Zasińska
    2019 MATERIALS AND MANUFACTURING PROCESSES

    The objective of the present project was to determine the effects of powder granulation (fraction of grain size) for the Ti-13Nb-13Zr alloy, produced by powder metallurgy, on its porosity, grain cohesion, compressive strength, and Young`s modulus. Two powder fractions, 45–105 µm, and 106–250 µm were applied. The 50 mass pct of NH4HCO3 was added as a space holder. The specimens were in compaction stage uniaxially pressed at pressure 625 MPa for 120 s. The brown bodies were sintered at a temperature 1150°C for 3.5 h. The well-joined grains were observed for both powder granulations. The increase in powder granulation resulted in an increase of porosity from 51% to 59%, and it was only 30% with no space holder used. The compressive strength increased with decreased porosity from 57 to 236 MPa. Young`s modulus was measured as 4.8 GPa for finer powder and 0.9 GPa for coarser powder. It is evident from the results obtained that the applied process parameters, the space holder and its fraction, and the use powder granulation between 45 and 105 µm bring out the porous material fulfilling mechanical and biological requirements specific of load-bearing titanium implants.

  • Prace doktorskie, habilitacje oraz profesury o tematyce chemii analitycznej i pokrewnej w 2018 r.
    • Marek Biziuk
    • Żaneta Polkowska
    2019 Analityka: Nauka i Praktyka

    Zestawienie prac doktorskich habilitacji oraz profesur o tematyce chemii analitycznej i pokrewnej w 2018 r. w Polsce.

  • Prace Komisji Historycznej SEP przy wydaniu "Historii Elektryki Polskiej"
    • Dariusz Świsulski
    2019 Wiadomości Elektrotechniczne

    Przedstawiono prace Komisji Historycznej Stowarzyszenia Elektryków Polskich związane ze zbieraniem materiałów i wydaniem pięciotomowego opracowania Historia Elektryki Polskiej.

  • Prądy łożyskowe w układach napędowych z silnikami indukcyjnymi
    • Jarosław Guziński
    • Krzysztof Łuksza
    2019 Automatyka Elektryka Zakłócenia

    W pracy przedstawiono problemy występujące w układach napędowych z silnikami indukcyjnymi zasilanymi z falownika napięcia. Zwrócono uwagę na rosnącą liczbę uszkodzeń silników w napędach przekształtnikowych. Wskazano przyczyny wynikające z charakteru zasilania przekształtnikowego silnika. Główną uwagę poświęcono prądowi łożyskowemu, który odpowiada za większość awarii maszyn. Przedstawiono rodzaje prądów łożyskowych, wyjaśniając fizykę zjawisk. Wymieniono sposoby ochrony silników przed oddziaływaniem prądów łożyskowych. Zaprezentowano przykładowe rozwiązanie filtru składowej zerowej.

  • Precipitation of Spherical Vaterite Particles via Carbonation Route in the Bubble Column and the Gas-Lift Reactor
    • Donata Konopacka-Łyskawa
    • Barbara Kościelska
    • Marcin Stanisław Łapiński
    2019 Pełny tekst JOM-US

    Spherical vaterite particles were produced by carbonation of calcium chloride solution with addition of ammonia to facilitate CO2 absorption. Synthesis of calcium carbonate was carried out in a bubble column or gas-lift reactor. The course of the reaction was monitored by pH measurements. Precipitated solids were analyzed by Fourier-transformed infrared spectroscopy, x-ray powder diffraction and scanning electron microscopy, and the particle size distribution was determined by a laser diffraction method. Synthesized calcium carbonate products were mainly vaterite. The calcium chloride concentration and carbon dioxide volume fraction in a gas phase had the main impact on the size of the produced particles in both reactors. A slight decrease in the mean particle size was observed for the highest mixing intensity. Both tested reactors can be applied to produce vaterite particles, although formation of homogeneous nonagglomerated spherical particles in a gas-lift reactor required careful selection of the process parameters.

  • Precise Bathymetry as a Step Towards Producing Bathymetric Electronic Navigational Charts for Comparative (Terrain Reference) Navigation
    • Andrzej Stateczny
    • Daria Gronska-Sledz
    • Weronika Motyl
    2019 Pełny tekst JOURNAL OF NAVIGATION

    Bathymetric Electronic Navigational Charts (bENCs) contain only bathymetry data and can be used in applications such as underwater positioning, dredging and piloting. According to International Hydrographic Organization (IHO) standard S-57, Electronic Navigational Charts (ENCs) contain depth information with pure density of depth contours. Typical depth contours encoded by Hydrographic Offices are limited to 2, 5, 10 and 20 m. Availability of more depth contours in bENCs would allow the visualisation of a safety contour which is closer to users’ specific needs, especially in restricted waters such as ports, lakes and rivers. Another problem is non – Global Navigation Satellite System (GNSS) Unmanned Underwater Vehicle (UUV) navigation. bENCs could be used as reference data for UUV comparative navigation. This is called terrain reference navigation. This article presents the results from bathymetric data processing that was performed to convert data contained in bENCs into a reference for underwater comparative navigation. We use data obtained using a multibeam echo sounder to produce depth data with a horizontal spacing of 0·10m that is suitable for use in restricted waters. The experimental data was collected in and around the Port of Gdansk, Poland.

  • Predicting Performance of Lightweight Concrete with Granulated Expanded Glass and Ash Aggregate by Means of Using Artificial Neural Networks
    • Marzena Kurpińska
    • Leszek Kułak
    2019 Pełny tekst Materials

    Lightweight concrete (LWC) is a group of cement composites of the defined physical, mechanical, and chemical performance. The methods of designing the composition of LWC with the assumed density and compressive strength are used most commonly. The purpose of using LWC is the reduction of the structure’s weight, as well as the reduction of thermal conductivity index. The highest possible strength, durability and low thermal conductivity of construction materials are important factors and reasons for this field’s development, which lies largely in modification of materials’ composition. Higher requirements for construction materials are related to activities aiming at environment protection. The purpose of the restrictions is the reduction of energy consumption and, as a result, the reduction of CO2 emission. To limit the scope of time-consuming and often high-cost laboratory works necessary to calibrate models used in the test methods, it is possible to apply Artificial Neural Networks (ANN) to predict any of the concrete properties. The aim of this study is to demonstrate the applicability of this tool for solving the problems, related to establishing the relation between the choice of type and quantity of lightweight aggregates and the porosity, bulk density and compressive strength of LWC. For the tests porous lightweight Granulated Expanded Glass Aggregate (GEGA) and Granulated Ash Aggregate (GAA) have been used.

  • Prediction of ship resistance with the use of Full-scale CFD simulations
    • Karol Niklas
    • Hanna Pruszko
    2019

    In recent years, the IMO has introduced new regulations to reduce the negative impact of ships on the natural environment. A particularly important step forcing technological innovations is the increasing requirement of ship energy efficiency. It is expressed by the Energy Efficiency Design Index (EEDI). Another important step towards green shipping is rising the required quality of fuel used for propulsion, so called Tier limits. Higher demand of Low Sulfur Fuel Oil resulted in its price raised up b 200% in recent 2 years. All these aspects increase the importance of ship’s fuel economy. As a result, the hull resistance reduction plays a significant role in a design process of a new vessels. For vessels operating at sites with moderate and rough waves the shape of a hull, and in particular of a bow section, plays an important role. The paper presents results of some of the research carried out as a part of the "Smart Propulsion System" research project. The presented stage of the work includes a fullscale CFD simulation for a case study ship redesigned from 'as built' V-shaped bulbous bow to three different innovative variants. Changes in a hull form were made in such a way that the redesigned hull versions preserved main dimensions and hydrostatic parameters of the original design. The paper presents ship resistance analysis on calm water as a part of seakeeping analysis. Scope of the work was full-scale CFD simulations of four innovative hull forms in order to determine total resistance, dynamic trim and sinkage. The influence of bow and stern shape, wetted surface area and waterplane area on a total resistance was investigated. Main conclusions were formulated for novel hull forms being analyzed. Scope of further work was formulated and it included assessment of combined influence of the ship’s speed and waving conditions on the performance at specific operational site. To reduce fuel consumption the optimal design and operation of the ship are equally important and can be supported by fullscale CFD simulations.

  • Prediction of the Biogenic Amines Index of Poultry Meat Using an Electronic Nose
    • Wojciech Wojnowski
    • Kaja Kalinowska
    • Tomasz Majchrzak
    • Justyna Płotka-Wasylka
    • Jacek Namieśnik
    2019 Pełny tekst SENSORS

    The biogenic amines index of fresh chicken meat samples during refrigerated storage was predicted based on the headspace analysis using an electronic nose equipped with an array of electrochemical sensors. The reference biogenic amines index values were obtained using dispersive liquid–liquid microextraction–gas chromatography–mass spectrometry. A prototype electronic nose with modular construction and a dedicated sample chamber was used to rapidly analyze the volatile fraction of chicken meat samples, with a single measurement time of five minutes. Backpropagation artificial neural network was used to estimate the biogenic amines index of the samples with a determination coefficient of 0.954 based on ten-fold stratified cross-validation. The results indicate that the determination of the biogenic amines index is a good reference method for studies in which the freshness of meat products is assessed based on headspace analysis and fingerprinting, and that the described electronic device can be used to assess poultry meat freshness based on this value with high accuracy.

  • Predykcyjne sterowanie równoległym filtrem aktywnym ze sprzężeniem od prądu zasilającego
    • Agata Bielecka
    • Daniel Wojciechowski
    2019 Pełny tekst Przegląd Elektrotechniczny

    Artykuł przedstawia nowatorską strategię predykcyjnego sterowania równoległym energetycznym filtrem aktywnym (EFA). Proponowane sterowanie zawiera sprzężenie zwrotne od prądu zasilającego i wiąże zalety sterowania w układzie otwartym oraz zamkniętym – szybkość reakcji na zmianę prądu odbioru i bardzo wysoką skuteczność kompensacji. Wysoka jakość prądu kompensacyjnego wynika również z zastosowania w sterowaniu algorytmów predykcyjnych, a także z faktu przyłączenia przekształtnika do sieci poprzez obwód LCL. W artykule przedstawiono wyniki badań symulacyjnych proponowanego algorytmu sterowania.

  • Preference-based evolutionary multi-objective optimization in ship weather routing
    • Joanna Szłapczyńska
    • Rafał Szłapczyński
    2019 Pełny tekst APPLIED SOFT COMPUTING

    In evolutionary multi-objective optimization (EMO) the aim is to find a set of Pareto-optimal solutions. Such approach may be applied to multiple real-life problems, including weather routing (WR) of ships. The route should be optimal in terms of passage time, fuel consumption and safety of crew and cargo while taking into account dynamically changing weather conditions. Additionally it must not violate any navigational constraints (neither static nor dynamic). Since the resulting non-dominated solutions might be numerous, some user support must be provided to enable the decision maker (DM) selecting a single ‘‘best’’ solution. Commonly, multi-criteria decision making methods (MCDM) are utilized to achieve this goal with DM’s preferences defined a posteriori. Another approach is to apply DM’s preferences into the very process of finding Pareto-optimal solutions, which is referred to as preference-based EMO. Here the Pareto-set is limited to those solutions, which are compliant with the pre-configured user preferences. The paper presents a new tradeoff-based EMO approach utilizing configurable weight intervals assigned to all objectives. The proposed method has been applied to ship WR problem and compared with a popular reference point method: r-dominance. Presented results prove applicability and competitiveness of the proposed method to solving multi-objective WR problem.

  • Preliminary Citation and Topic Analysis of International Conference on Agile Software Development Papers (2002-2018)
    • Muhammad Ahmad
    2019 Pełny tekst Annals of Computer Science and Information Systems

    This study utilizes citation analysis and automated topic analysis of papers published in International Conference on Agile Software Development (XP) from 2002 to 2018. We collected data from Scopus database, finding 789 XP papers. We performed topic and trend analysis with R/RStudio utilizing the text mining approach, and used MS Excel for the quantitative analysis of the data. The results show that the first five years of XP conference cover nearly 40\% of papers published until now and almost 62\% of the XP papers are cited at least once. Mining of XP conference paper titles and abstracts result in these hot research topics: ``Coordination'', ``Technical Debt'', ``Teamwork'', ``Startups'' and ``Agile Practices'', thus strongly focusing on practical issues. The results also highlight the most influential researchers and institutions. The approach applied in this study can be extended to other software engineering venues and applied to large-scale studies.

  • Preliminary Investigation on Auto-Thermal Extrusion of Ground Tire Rubber
    • Łukasz Zedler
    • Daria Kowalkowska-Zedler
    • Henri Vahabi
    • Mohammad Saeb
    • Xavier Colom
    • Javier Cañavate
    • Shifeng Wang
    • Krzysztof Formela
    2019 Pełny tekst Materials

    Ground tire rubber (GTR) was processed using an auto-thermal extrusion as a prerequisite to green reclaiming of waste rubbers. The reclaimed GTR underwent a series of tests: thermogravimetric analysis combined with Fourier-transform infrared spectroscopy (TGA-FTIR), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and static headspace and gas chromatography-mass spectrometry (SHS-GC-MS) in order to evaluate the impact of barrel heating conditions (with/without external barrel heating) on the reclaiming process of GTR. Moreover, samples were cured to assess the impact of reclaiming heating conditions on curing characteristics and physico-mechanical properties. Detailed analysis of the results indicated that the application of auto-thermal extrusion is a promising approach for the sustainable development of reclaiming technologies.

  • Preliminary results from HEDGEHOG REXUS Project - sounding rocket experiment on accelerations, vibrations and heat flow
    • Adam Dąbrowski
    • Karol Pelzner
    • Szymon Krawczuk
    • Jacek Goczkowski
    • Agnieszka Elwertowska
    2019

    As access to space conditions becomes more available, both technically and economically, scientists' interest in launching finer and more sophisticated experiments grows. This applies now more than ever to fragile by nature biological and chemical experiments. To be qualified for launch, such experiments need to be carefully tested prior to the event. The tests should represent actual launch conditions as closely and in as detailed manner as possible. For this reason, comprehensive measurements of launch conditions are required. Most important acceptance tests required for module acceptance are vibration tests and thermal tests. This experiment focuses on measuring acceleration and vibrations (especially eigenfrequencies) conditions and heat transfer inside a sounding rocket as a reference for future ground acceptance tests. The experiment's scientific challenge is to obtain precise information on acceleration and vibration environment that payload is subject to during whole course of sounding rocket an envelope of environmental conditions is known and publicly available, including spectral data their application is usually limited to serving as general guideline due to their lack of details. In case of vibrations, this is usually low frequency range of measurements, as high frequency vibrations tend to be less important for sturdy REXUS experiments. The second scientic objective is to measure temperaturein various locations of the section of the sounding rocket. With such data, it would be possible to create the model of heat cation of future payload. Previous REXUS experiments typically included single point temperature measurements, focusing on local effects rather than heat transfer phenomena. Preliminary results from flight that took place in early March 2019 in Kiruna, Sweden will be presented. Copyright © 2019 by the International Astronautical Federation (IAF). All rights reserved.

  • Preliminary Results of a System-theoretic Assessment of Maritime Autonomous Surface Ships' Safety
    • Krzysztof Wróbel
    • Przemysław Krata
    • Jakub Montewka
    2019 Pełny tekst TransNav - The International Journal on Marine Navigation and Safety of Sea Transportation

    While a system‐theoretic approach to the safety analysis of innovative socio‐technical systems gains a growing acceptance among academia, safety issues of Maritime Autonomous Surface Ships (MASS) remain largely unexplored. Therefore, we applied a System‐Theoretic Process Analysis to develop and analyze a preliminary model of the unmanned shipping system in order to elaborate safety recommendations for future developers of the actual system. Results indicate that certain advancements shall be undertaken in relation to MASS’ software solutions in particular.