2019 - Repozytorium publikacji - Politechnika Gdańska

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Capacity analysis of the selected track system in partially ordered space
- Eligiusz Mieloszyk
- Anita Milewska
- Sławomir Grulkowski
2019 Pełny tekst MATEC Web of Conferences
A proper location of the interval sections has significant impact on the traffic flow in the railway track network. This issue is critical during line modernization as well as when a new solution accounting for the traffic forecast at particular element of the railway track network is developed . However, the situation is more complex and more expensive for railway stations since improvement of the capacity requires critical organizational changes and additional investments. We have applied partially ordered linear spaces to study the capacity of a track system.
Capon-like DoA estimator for rotating arrays
- Michał Meller
- Kamil Stawiarski
2019 Pełny tekst
We propose a nonparametric superresolution DoA estimator that is suitable for use with rotating arrays. The proposed method can be regarded as an extension of the Capon approach. We investigate its properties using computer simulations and present results obtained by processing of real world data.
Catalytic Activity of Nickel and Ruthenium–Nickel Catalysts Supported on SiO2, ZrO2, Al2O3, and MgAl2O4 in a Dry Reforming Process
- Izabela Wysocka
- Andrzej Rogala
- Jan Hupka
2019 Pełny tekst Catalysts
Dry reforming of methane (DRM) is an eco-friendly method of syngas production due to the utilization of two main greenhouse gases—methane and carbon dioxide. An industrial application of methane dry reforming requires the use of a catalyst with high activity, stability over a long time, and the ability to catalyze a reaction, leading to the needed a hydrogen/carbon monoxide ratio. Thus, the aim of the study was to investigate the effect of support and noble metal particles on catalytic activity, stability, and selectivity in the dry reforming process. Ni and Ni–Ru based catalysts were prepared via impregnation and precipitation methods on SiO2, ZrO2, Al2O3, and MgAl2O4 supports. The obtained catalysts were characterized using X-ray diffractometry (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES), Brunauer–Emmett–Teller (BET) specific surface area, and elemental carbon-hydrogen-nitrogen-sulphur analysis (CHNS) techniques. The catalytic activity was investigated in the carbon dioxide reforming of a methane process at 800 ◦C. Catalysts supported on commercial Al2O3 and spinel MgAl2O4 exhibited the highest activity and stability under DRM conditions. The obtained results clearly indicate that differences in catalytic activity result from the dispersion, size of an active metal (AM), and interactions of the AM with the support. It was also found that the addition of ruthenium particles enhanced the methane conversion and shifted the H2/CO ratio to lower values.
Causes of damage and methods of repairing floor made on polystyrene concrete
- Paweł Piotrkowski
- Łukasz Drobiec
2019 Pełny tekst MATEC Web of Conferences
The paper describes damages, tests and repair of the floor made on existing ceiling and expanded polystyrene concrete underlay. The floor was built on a reinforced concrete ceiling with an area of about 1050 m2. Significant damage in the form of cracks, detachments and unevenness was found in the floor. In order to determine the causes of damage, in situ tests and laboratory tests were carried out. It was found that the damage was caused by numerous performance errors. A test repair of the damage (4.7x6.0 m) was carried out, and then the repair method was applied on the entire floor surface.
Cavitation Erosion Resistance Influence of Material Properties
- Dominika Zakrzewska
- Alicja Krella
2019 Pełny tekst Advances in Materials Science
The cavitation erosion is the phenomena that causes degradation of fluid flow machinery components due to repetitive implosion of cavitation bubbles adjacent to the solid surface. Cavitation erosion is a complex phenomenon, which includes not only hydrodynamic factors of liquid, but also properties of erodible material e.g. microstructure, hardness or Young modulus. In order to reduce the negative impact of erosion on machine components, there are many methods to increase cavitation erosion resistance. The paper discusses the correlations between structural and mechanical properties and the resistance to cavitation erosion (CER) of pure materials, their alloys and coatings. Methods to increase CER have also been described - using heat / thermochemical treatment and application of coatings by various methods.
Ceglana tożsamość. Dziedzictwo materialne jako rdzeń gdańskich tożsamości
- Jakub Szczepański
2019 Pełny tekst Miscellanea Anthropologica et Sociologica
Artykuł dotyczy cegły elewacyjnej jako materiału budowlanego będącego istotnym elementem kształtowania gdańskiej tożsamości.
CeIr3: superconductivity in a phase based on tetragonally close packed clusters
- Karolina Górnicka
- Elizabeth M. Carnicom
- Sylwia Gołąb
- Marcin Stanisław Łapiński
- Bartłomiej Wiendlocha
- Weiwei Xie
- Dariusz Kaczorowski
- Robert J. Cava
- Tomasz Klimczuk
2019 SUPERCONDUCTOR SCIENCE & TECHNOLOGY
We present the crystallographic analysis, superconducting and spectroscopic characterization, and theoretical modeling of CeIr3. Lattice parameters a = 5.2945(1) Å and c = 26.219(1) Å are found for the R-3m symmetry crystal structure, which are close to the literature values. CeIr3 is a moderate type-II superconductor (κ GL = 17, λ e–p = 0.65) below 2.5 K. Ce ions exhibit a strongly intermediate valence character as evidenced by x-ray photoelectron spectroscopy. The normal state magnetic susceptibility is weakly temperature dependent and follows the inter-configuration fluctuation model with a singlet Ce−4 f 0 ground state. Theoretical calculations support a non-magnetic ground state of the system and reveal that Ir−5d states are dominant at the Fermi level.
Cel i funkcje zamówień publicznych
- Mariusz Zaborowski
2019 Pełny tekst Optimum. Studia Ekonomiczne
System zamówień publicznych, obok zagadnień prawnych, obejmuje między innymi również zagadnienia organizacyjne, czy też ekonomiczne. Dlatego elementy systemowe należy rozpatrywać w bardzo szerokim ujęciu i nie można zawężać ich tylko do zagadnień prawnych. Cele i funkcje zamówień przeplatają się nawzajem i tym samym są od siebie niezależne. Nie można mówić o celach bez wyraźnego oparcia w funkcjach zamówień publicznych i odwrotnie. Dlatego treść i cel systemu zamówień publicznych determinuje wielość funkcji, jakie pełni jego regulacja i tym samym wpływa na gospodarkę i podmioty występujące na rynku.
Centralny serwer w multimedialnym systemie dyspozytorsko-teleinformatycznym STRADAR
- Marek Blok
- Sylwester Kaczmarek
- Maciej Sac
2019 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
Przedstawiono architekturę i najnowsze funkcje centralnego serwera (Centrum) w rozproszonym systemie monitorowania akwenów morskich opracowanym dla straży granicznej. System umożliwia prezentację bieżącej i archiwalnej sytuacji na mapie, obrazu z kamer, rozmów telefonicznych oraz plików i wiadomości tekstowych (SMS) wymienianych przez funkcjonariuszy straży granicznej. W artykule skupiono się na nowych funkcjonalnościach centrum, związanych ze sterowaniem kamerami oraz wizualizacją danych radarowych przechowywanych w serwerach archiwizacji pochodzących z radarów ARPA oraz Terma SCANTER 2001.
CFGFRPT Piles with a Circular Cross-Section and their Application in Offshore Structures
- Eligiusz Mieloszyk
- Marcin Abramski
- Anita Milewska
2019 Pełny tekst Polish Maritime Research
The possibilities of using concrete piles in a polymer composite reinforced with glass fibres in offshore facilities were shown. Laboratory tests of CFGFRPT type piles compressed axially and in eccentric compression for the analysis of CFGFRPT piles were used. Methods of analysis of dynamic systems for mathematical modelling of the displacement of the hammer in the pile driving process were applied. The possibilities of combining CFGFRPT piles, including the creation of hybrid piles were also presented. For example, concrete piles can be combined with concrete piles in a polymer composite reinforced with glass fibres with different fibre beam angles. The possibilities of using such hybrid piles in offshore facilities were indicated.
CHALK & TALK OR SWIPE & SKYPE?
- Ewa Kozłowska
- Rob Howard
2019 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Technology in classroom is a matter of heated discussions in the field of education development, especially when multidisciplinary education goes along with language skills. Engineers’ education requires theoretical and practical knowledge. Moreover, dedicated computer skills become crucial for both young graduates and experienced educators on the labor market. Teaching online with or without using different Learning Management Systems (LMS) became an integrated part of teaching and grading systems at most of the universities. Unfortunately, the overuse of technology happens to result in lower learning efficiency instead of bringing development. In this article examples of overuse or misuse of technology in the classroom were discussed and some case study improvements were presented, based on case studies investigated by the representatives of Gdansk University of Technology and Online Language Center.
Change in Heavy Metals Concentrations in Sediments Deposited in Retention Tanks in a Stream after a Flood
- Nicole Nawrot
- Karolina Matej-Łukowicz
- Ewa Wojciechowska
2019 Pełny tekst POLISH JOURNAL OF ENVIRONMENTAL STUDIES
Our paper presents the results of heavy metal (HM) (Zn, Cu, Pb, Cd) content in bottom sediments from retention tanks along Oliwa Stream in Gdańsk, Poland, before a flood (BF) and after a flood (AF) 14-15 July 2016. The flood had a huge impact on the quality of bottom sediments and their displacement. The concentrations of HM differed significantly for research series conducted 3 months BF and 8 months AF. The concentration of Cu increased from 3.5 mg/kg to 88.8 mg/kg BF and from 12.1 mg/kg to 1,114.3 mg/kg AF, Zn from 27.4 mg/kg to 129.9 mg/kg BF; and 42.3 mg/kg to 244.8 mg/kg AF, Cd from 0.04 mg/kg to 0.47 mg/kg BF, and 0.08 mg/kg to 0.47 mg/kg AF. Also, the migration of some metals, mostly Cu to retention tanks located downstream, was observed, resulting from the washing away of sediments in the upper part of the stream. Since the stream inflows to the Gulf of Gdansk, urban flooding created a risk of migration of contaminants to the Baltic Sea.
CHANGES TAKING PLACE IN THE KINETIC ARCHITECTURE OVER THE 20TH AND 21ST CENTURIES
- Jan Cudzik
2019 Pełny tekst Przestrzeń i Forma
Kinematics has accompanied architecture from its beginning and is strongly associated with its evolution. Over the centuries, it has changed form and function. However, its rank grew at the beginning of the 20th century. Along with the widespread change of the design method in the early 90s of the twentieth century, its forms have become more complex. The study showed that with the development of design techniques, this time should be treated as a breakthrough in the design of kinematic architecture.
Channel Blockage and Flow Maldistribution during Unsteady Flow in a Model Microchannel Plate heat Exchanger
- Paweł Dąbrowski
- Michał Klugmann
- Dariusz Mikielewicz
2019 Pełny tekst Journal of Applied Fluid Mechanics
This paper describes the problem of channel blockage as a result of flow maldistribution between the channels of a model mini channel plate heat exchanger consisting of one pass on each leg. Each leg of the heat exchanger contains 51 parallel and rectangular minichannels of four hydraulic diameters namely 461 μm, 571 μm, 750 μm and 823 μm. In addition, a more complex geometry has been investigated where for the sake of breaking the development length the inclined transverse cuts have been incorporated. The moment of liquid phase transition through the exchanger (the working medium: water) was recorded for the mass fluxes ranging from 18.67 to 277.76 kg/m2s in 51 parallel channels with the use of a fast speed camera. The Reynolds numbers Re in the individual channels were from 10.76 to 90.04. The relationship between the mass flux and the size of the minichannels in the presence of the maldistribution is discussed here. The existence of the threshold in the mass flux below which the phenomenon occurs has been shown. Two mechanisms of channel blocking have been recorded and described in detail. A miniscale variation of one of them containing the extended geometry was created as well.
Characterization methods of nickel nano-particles obtained by the ex-solution process on the surface of Pr, Ni-doped SrTiO3 perovskite ceramics
- Bartosz Kamecki
- Tadeusz Miruszewski
- Karolina Górnicka
- Tomasz Klimczuk
- Jakub Karczewski
2019 Pełny tekst SN Applied Sciences
In this paper, a novel electrode material based on Pr, Ni co-doped strontium titanate ( Sr0.7Pr0.3)xTi1−yNiyO3 with constant amount of 30% praseodymium dopant, different amount of nickel (y = 0.06 and y = 0.10) and additional nonstoichiometry in Sr-site (x = 1; x = 0.9 and x = 0.8) was investigated as fuel electrode for SOEC devices. A porous ceramics were prepared by solid-state reaction method. X-ray diffraction measurements revealed single phase materials with perovskite structure. Ex-solution method makes the grain surface covered by nickel nanoparticles. The influence of nickel amount, non-stoichiometry, synthesis and reduction conditions on formation of nanoparticles was investigated. Size, distribution and ability to agglomeration of Ni nanoparticles were analyzed by the scanning electron microscopy. The quantity of ex-soluted Ni particles was calculated from magnetization measurement. The total electrical conductivity of samples was measured by DC 4-wire method in the range of 100–800 °C at different atmospheres. Electrical measurements showed total electrical conductivity higher than 10 S cm−1 in a wide temperature range. All obtained results confirmed that analyzed donor and acceptor co-doped SrTiO3 materials with Ni nanoparticles after ex-solution process should be a good candidate to improve a catalysis process on fuel electrode surface.
Characterization of Slow and Fast Fading in Off-Body Communication at 2.45 GHz with Space Diversity Scheme in an Indoor Environment
- Szymon Wiszniewski
- Sławomir Ambroziak
2019 Pełny tekst International Journal of Antennas and Propagation
The characterization of slow and fast fading in wireless body area networks with space diversity scheme has been presented. The analysis, based on the measurements at 2.45 GHz in an indoor environment, has shown that for all investigated configurations of receiving wearable antennas, the correlation coefficient values of the received signals’ parameters are below the assumed value of 0.5, being close to zero for the vast majority of cases. It has been shown that the slow fading component may be modelled by a lognormal distribution with zero average and the standard deviation from the range of [1.43, 1.98] dB. The fast fading component is the best modelled by a Rice distribution with the noncentrality parameter and the scale parameter being in the range [0.8125, 0.9624] and [0.5269, 0.6954], respectively.
Characterization of slow and fast fading in off-body communication at 2.45 GHz with space diversity scheme in indoor environment
- Szymon Wiszniewski
- Sławomir Ambroziak
2019
The characterization of slow and fast fading in Wireless Body Area Networks with space diversity scheme has been presented. The analysis, based on the measurements at 2.45 GHz in indoor environment, has shown that for all investigated configurations of receiving wearable antennas the correlation coefficient values of received signals’ parameters are below the assumed value of 0.5, being close to zero for the vast majority of cases. It has been shown that the slow fading component may be modelled by a lognormal distribution with zero average and the standard deviation from the range of [1.43, 1.98] dB. The fast fading component is the best modelled by a Rice distribution with the non-centrality parameter and the scale parameter being in the range [0.8125, 0.9624], and [0.5269, 0.6954], respectively.
Charakterystyka elektrochemiczna odporności korozyjnej aluminium i jego stopów w wodnych środowiskach zasadowych
- Joanna Wysocka
2019 Pełny tekst
Rozprawa doktorska przedstawia charakterystykę elektrochemiczną odporności korozyjnej aluminium i jego stopów w wodnych środowiskach zasadowych. Główne elementy pracy to część literaturowa, w której zarysowano problem badawczy i szczegółowo omówiono zagadnienia związane z korozją aluminium oraz, po przedstawieniu tez pracy i jej zakresu, część eksperymentalna i badawcza. Praca skupia się na kompleksowemu opisowi mechanizmów korozji aluminium. Ukazano w niej również wpływ czynników mikrostrukturalnych na kinetykę procesu degradacji, wynikającą z obecności dodatków stopowych. Główny trzon pracy opiera się na opisie roli dodatku związków nieorganicznych i organicznych w środowisku elektrolitycznym na ograniczenie degradacji stopów aluminium. Na wybranych przykładach opisano różnice dotyczące typu i liczby grup funkcyjnych występujących w obrębie analizowanej molekuły inhibitora, podjęto też próbę klasyfikacji związków o charakterze inhibitorów korozji, obecnych w obrębie złożonych mieszanin ekstraktów naturalnych. W ramach pracy zaproponowano nowatorską metodykę pomiarową do wyznaczania izoterm adsorpcji, bazującą na chwilowych pomiarach impedancji układu zmieniającego się na skutek nastrzyku inhibitora. Metodykę tę cechuje wyższa dokładność i szybkość realizacji pomiaru, a także możliwość oznaczenia granicznego stężenia inhibitora, dla którego metal pokrywa się monowarstwą adsorpcyjną.
CHARAKTERYSTYKA I ZAKRES STOSOWANIA TYNKÓW
- Maciej Niedostatkiewicz
- Tomasz Majewski
2019 Pełny tekst Izolacje
Wyprawy tynkarskie, potocznie nazywane tynkami, wykorzystywane są w budownictwie od wielu tysiącleci. Niektóre rodzaje tynków stosowane są w niemal niezmienionej postaci do dnia dzisiejszego, jednak wiele nowych typów wypraw tynkarskich opracowano w ciągu ostatnich kilkudziesięciu lat. Kiedyś przeważnie były przygotowywane w całości na budowie, obecnie w większości przypadków wytwarzane są w postaci suchych mieszanek, gotowych do zarobienia wodą, lub jako gotowe masy tynkarskie do ułożenia na powierzchni.
Charakterystyka oporności Klebsiella pneumoniae New Delhi na karbapenemy
- Magdalena Fordon
- Beata Krawczyk
2019 Pełny tekst
Bakterie Klebsiella pneumoniae New Delhi, posiadające gen oporności na karbapenemy (blaNDM) zostały po raz pierwszy wyizolowane w 2008 roku w Szwecji od pacjenta wcześniej hospitalizowanego w Indiach. Bakterie te szybko rozprzestrzeniają się po całym świecie, a od 2011 roku występują również w Polsce. Stanowią one wysokie ryzyko epidemiologiczne, ponieważ gen oporności na karbapenemy przekazywany jest pomiędzy bakteriami poprzez horyzontalny transfer genów, a międzynarodowe podróże dodatkowo sprzyjają migracji szczepów NDM-pozytywnych. Badania mające na celu ułatwienie różnicowania genetycznego tych szczepów oraz ich charakterystykę są zatem niezwykle istotne. Praca miała na celu charakterystykę oporności szczepów Klebsiella pneumoniae New Delhi na karbapenemy, z uwzględ-nieniem budowy, funkcjonowania oraz różnych wariantów enzymu za nią odpowiedzialnego.