2016 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2016

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Structured populations with diffusion and Feller conditions
- Agnieszka Bartłomiejczyk
- Henryk Leszczyński
2016 Mathematical Biosciences and Engineering
We prove a weak maximum principle for structured population models with dynamic boundary conditions. We establish existence and positivity of solutions of these models and investigate the asymptotic behaviour of solutions. In particular, we analyse so called size profile.
Struktura sektora bankowego w wybranych krajach Bałkanów Zachodnich
- Katarzyna Kubiszewska
2016 Pełny tekst Bezpieczny Bank
W sektorze bankowym zjawisko konkurencji pojawiło się później niż w tradycyjnych sektorach przemysłowych, lecz w warunkach współczesnych rozwija się bardzo dynamicznie i przybiera często agresywne formy. Sektory bankowe równią się pod względem struktur konkurencyjnych, jak i poziomów koncentracji. Celem artykułu jest zaprezentowanie struktury rynków bankowych w wybranych krajach Europy Bałkańskiej, przechodzących transformację systemową. Artykuł ma odpowiedzieć na pytanie, czy kraje wywodzące się z jednego państwa, rozwijają rynek bankowy, pod względem jego struktury, w analogiczny sposób. Badanie przeprowadzono za okres badawczy to lata 2004 – 2014, dla trzech sektorów tj. w Chorwacji, Serbii oraz Macedonii, w podziale na trzy grupy banków: małe, średnie oraz duże, uwzględniając zarówno liczbę działających banków, wartość aktywów, jak i poziom koncentracji rynków.
Struktura systemu sterowania statkiem dynamicznie pozycjonowanym.
- Roman Śmierzchalski
2016 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
W artykule przedstawiono funkcje i zadania systemu dynamicznego pozycjonowania (DP) statku. Omówiono zagadnienia sterowania - stabilizacji pozycji i kierunku (kursu rzeczywistego statku) przy małej prędkości manewrowania oraz modele statku DP. Określono wymagania towarzystw klasyfikacyjnych dla statków DP. Przedstawiono wielowarstwową strukturę systemu sterowania statkiem DP, gdzie do podstawowych problemów należy zaliczyć filtrację sygnałów oraz estymację wielkości mierzonych i niemierzonych, dobór metody sterowania i regulatora DP oraz alokację sterów i napędów.
Struktura źródeł finansowania ponadprzeciętnie rentownych przedsiębiorstw z sektora MSP
- Piotr Figura
2016 Pełny tekst Przedsiębiorstwo & Finanse
Celem artykułu jest przedstawienie w przekroju sektorowym kształtowania struktury finansowania przez MSP uzyskujące ponadprzeciętnie wysoką rentowność aktywów. W trakcie przeprowadzonych badań uwzględniono 109 174 sprawozdań finansowych przedsiębiorstw prowadzących działalność gospodarczą w 27 różnych działach gospodarki narodowej. Sektorowe zróżnicowanie wartości wskaźników struktury źródeł finansowania zostało potwierdzone przy użyciu testu nieparametrycznego Kruskala-Wallisa. Przeprowadzone badania dowiodły, że MSP należące do różnych działów gospodarki w odmienny sposób kształtują strukturę swoich źródeł finansowania. Do finansowania swojego majątku wykorzystują one przede wszystkim kapitał własny. Spośród zewnętrznych obcych źródeł finansowania zdecydowanie bardziej preferowany jest, przez te firmy, kapitał o charakterze krótkoterminowym. Artykuł zawiera także propozycje baz odniesienia dla wskaźników struktury źródeł finansowania, dostosowanych do specyfiki MSP z 27 różnych działów gospodarki narodowej.
Struktury supramolekularne
- Radosław Pomećko
- Kamila Sadowska
- Izabela Kondratowicz
2016
W 1987 roku, w uznaniu osiągnięć nad rozwojem i zastosowaniem cząsteczek zdolnych do selektywnych oddziaływań uzależnionych od struktury, Akademia Noblowska nagrodziła trzech naukowców - Donalda J. Crama, Jean-MArie Lehna i Charlesa Pedersena.
Studenci, doktoranci i stażyści z Ukrainy na polskich uczelniach
- Krystyna Gomółka
2016 Przegląd Wschodnioeuropejski
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Studenci wobec pracy - porównanie opinii osób studiujących w Polsce i w Finlandii
- Michał Tomasz Tomczak
2016 Pełny tekst Edukacja Ekonomistów i Menedżerów
W artykule podjęto próbę scharakteryzowania opinii i oczekiwań wobec pracy studentów polskich i fińskich. Materiał empiryczny pozyskano metodą sondażową, w oparciu o ankietę przeprowadzoną wśród studentów uczelni w Polsce i Finlandii. Wśród wniosków z badania, podkreślić należy przede wszystkim wysoki poziom identyfikacji z uczelnią i wydziałem u studentów polskich oraz ich chęć do doskonalenia kwalifikacji; obawę o znalezienie satysfakcjonującego zatrudnienia charakteryzującą obie badane grupy oraz większą chęć do pracy w zespołach wielokulturowych w przypadku studentów fińskich.
Studenckie seminaria naukowe na Wydziale Mechanicznym Politechniki Gdańskiej - 50 lat historii
- Adam Barylski
2016 Technika Chłodnicza i Klimatyzacyjna
Omówiono historię studenckich seminariów naukowych organizowanych przez koła naukowe na Wydziale Mechanicznym Politechniki Gdańskiej od roku 1965. Organizowało je Koło Naukowe Studentów Mechaników Technologów, a od 1997 r. Koło Naukowe "Mechanik". Wymieniono organizatorów poszczególnych edycji i zwycięzców kolejnych sesji w kategorii studenci, absolwenci i doktoranci.
Studies of the mechanism of metal metal dusting of 10CrMo9-10 steel after 10 years of operation in trhe semi-regenerative catalytic reformer
- Marek Szkodo
- Grzegorz Gajowiec
2016 Pełny tekst CORROSION SCIENCE
The study showed that metal dusting mechanism of 10CrMo9-10 steel operated in industrial environment differs from models developed in laboratories. Significant differences lie in the fact that the models developed in laboratories only assume the formation of metastable carbide M3C, while studies have shown that the formation of M3C carbides is associated with the transformation of primary carbides and in the next stage is preceded by formation of the M23C6 carbides, which nucleate at M3C carbides/metal matrix interfaces. Their growth results in a spheroidal precipitates, and content of Cr & Mo in carbides increases with increasing distance from the surface.
Studies of the separation performance of silanized silica gel for simulated distillation
- Grzegorz Boczkaj
- Malwina Momotko
- Andrzej Przyjazny
- Marian Antoni Kamiński
2016 JOURNAL OF SEPARATION SCIENCE
We present the results of investigations of the chromatographic (sorptive) properties of silanized silica gel as a stationary phase for gas chromatography used for simulated distillation. Commercially available silanized sorbent (particle diameter range 63–200 m, average pore size 60 Å) was sieved to obtain the 80–100 mesh fraction (180–150 m). The obtained results revealed that silanized silica gel allows the complete separation of a mixture of nand iso-alkanes in the C1–C7 range. Such a separation is achieved with a temperature program starting with an initial temperature of 50°C, which is advantageous because the gas chromatograph oven does not have to be cooled below room temperature. The use of temperature programming with a final temperature of 300°C ensures separation and elution of all mixture components from C1 to n-C28 in one run. This study confirms the applicability of silanized silica gel as a stationary phase for the investigation of distillation temperature distribution of gasoline and diesel fuel based on the simulated distillation procedure according to ASTM D2887. The deviations of individual points of distillation curve obtained using ASTM D2887 and columns packed with silanized silica gel were within the reproducibility range of the standard procedure.
Study of displacements of a bridge abutment using FEM
- Michał Wymysłowski
- Zygmunt Kurałowicz
2016 Pełny tekst Studia Geotechnica et Mechanica
Steel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented to demonstrate these effects. The structure described is located over the Wieceminka river in the town of Kolobrzeg, Poland. It is a single-span road bridge with reinforced concrete slab.
STUDY OF SEASONAL ACOUSTIC PROPERTIES OF SEA WATER IN SELECTED WATERS OF THE SOUTHERN BALTIC
- Grażyna Grelowska
2016 Pełny tekst Polish Maritime Research
Climate Research of the globe is a current task, in particular to confirm the general hypothesis of global warming associated with an increase in average temperature. The sea acoustic climate is derived from the concept of climate and refers to the conditions of propagation of acoustic waves in a particular basin. In this paper, the results of systematic measurements of temperature, salinity and velocity distributions of sound in the area of the southern Baltic will be present. The focus will be on the results of extensive measurements carried out „in situ” in particular
Study of the effect of residues of pharmaceuticals on the environment on the example of bioassay Microtox®
- Monika Wieczerzak
- Błażej Kudłak
- Jacek Namieśnik
2016 Pełny tekst MONATSHEFTE FUR CHEMIE
Residues of pharmaceuticals present in the aqueous environment can be found in a mixture of different substances wherein drugs not remain inert with respect to each other. In such mixtures a phenomenon of synergism or antagonism may occur, which can contribute to increase or decrease the overall toxicity of the mixture of drugs. Pharmaceuticals namely: diclofenac (sodium salt), oxyteracycline hydrochloride, fluoxetine hydrochloride, chloramphenicol, progesterone, estrone, androstendione, ketoprofen and gemfibrozil were mixed with each other at different ratios of EC50 (effective concentration) and tested using MICROTOX®. Attempt was also made to determine whether a pH change of the sample containing pharmaceuticals affects the total toxicity of the sample. The most toxic mixtures of selected pharmaceuticals proved to be those containing diclofenac and chloramphenicol, reaching up to 90% of the toxicity against the test organism. Based on results obtained, it can be concluded that the change of pH has a significant effect on the toxicity of androstenedione, gemfibrozil, oxytetracycline hydrochloride, diclofenac and progesterone.
Study of the electrochemical stability of polypyrrole coating on iron in sodium salicylate aqueous solution
- Karolina Cysewska
- Sannakaisa Virtanen
- Piotr Jasiński
2016 SYNTHETIC METALS
In this work electrochemical stability of optimized PPy film on iron in aqueous solution of sodium salicylate is studied. The main drawback of conducting polymers is their possibility to undergo an irreversible degradation (overoxidation). The overoxidized polymers lose their properties, for example, conductivity and redox activity, what excludes them from some practical applications. This study demonstrates that lowering the concentration of salicylate in the electrolyte increases the electrode potential, at which overoxidation of PPy begins. It widens the electrode potentials, within which such a polymer can be used. Moreover, it is evidenced that even though the electrolyte concentration is lowered, the redox activity and the electrical properties of the PPy film are retained.
Study on a polish peat bog “Rucianka” as a source of yeast strains capable of effective phenol biodegradation
- Natalia Filipowicz
- Malwina Momotko
- Hubert Cieśliński
- Grzegorz Boczkaj
- Ewelina Krajewska
- Monika Wicka-Grochocka
- Marta Wanarska
- Józef Kur
2016 New Biotechnology
Phenol is one of the most widely distributed environmental pollutants which can be found in wastewaters and industrial effluents. Due to its toxicity and resistance to self-degradation, it could become even lethal for humans and animals. The treatment of this toxic compound is focused on psychical–chemical methods, although biological treatment of phenol is preferable for economic aspects related to relatively low cost of mineralization process and rare possibility of toxic secondary metabolites production. The aim of this study is to isolate yeasts from peat bog with potential for biodegradation of phenol at wide spectrum of con- centration. Isolated strains can be valuable for wastewater or soil treatments in temperate climate. In the proposed study 39 strains of yeast were isolated from soil and water samples collected from Rucianka raised bog. A prelim- inary test for screening of yeast capable of phenol biodegradation was performed on YNB slants with phenol concentration gradient. In the next step, strains were cultivated in MSM mineral medium with phenol at concentration 500–2000 mg/l, as a sole source of carbon, along with monitoring of OD 600 and phenol concentration by means of gas chromatography with flame ionization detector (GC-FID). All strains were cultivated under 18 ◦ C. The studies revealed that three strains exhibited an effective degradation of phenol at 500 mg/l and 750 mg/l concentration. Two strains were able to degradation of phenol at 1000 mg/l concen- tration. In all experiments, complete degradation of phenol was possible in less than 2 days.
Study on surface termination of boron-doped diamond electrodes under anodic polarization in H2SO4 by means of dynamic impedance technique
- Jacek Ryl
- Łukasz Burczyk
- Robert Bogdanowicz
- Michał Sobaszek
- Kazimierz Darowicki
2016 Pełny tekst CARBON
Anodic oxidation is a popular way to modify termination bonds at boron doped diamond electrodes altering their electrochemical and physicochemical properties. Our studies, performed with dynamic electrochemical impedance spectroscopy technique, supported with X-ray photoelectron spectroscopy and ellipsometry analysis prove its utility in continuous on-line monitoring of impedance changes on the electrode surface under polarization conditions, which may be of great use for the optimization of working conditions of the process. Based on our results, it can be observed that oxidation of termination bonds is a multistep process, each stage initiated at different anodic polarization potential. The factors influencing oxidation of termination bonds are presented and discussed. It was also possible to draw a conclusion about the removal of sp2 carbon impurities from the electrode surface as a precondition to activate the oxidation process. The depth and time of polarization, boron uptake at the grain boundaries, as well as crystallographic orientation of individual grains influence the heterogeneity of the oxidation process. Its partial reversibility was observed as a result of cathodic polarization in the range of hydrogen evolution, however due to irreversible corrosion of sp2 impurities, hydrogenation is not complete. This form of hydrogenation additionally contaminates the electrode surface with sulphur
STUDY ON THE EFFECTIVENESS OF THE TURBINE CONDENSER AIR EXTRACTION SYSTEM USING HYDRO EJECTORS
- Janusz Badur
- Tomasz Kowalczyk
- Paweł Ziółkowski
- Tokarczyk Piotr
- Woźniak Mariusz
2016 Transactions of the Institute of Fluid-Flow Machinery
The aim of the paper is to investigate the effectiveness of the 18K380 steam turbine condenser air extraction system using hydro ejectors. Motivation for the analysis is a need of improvement of the energy conversion ratio of the power plant. To achieve this goal it is necessary to establish efficiency of each subsystem of the energy cycle. The air extraction system is not a highly power consuming system but it has great impact on the steam cycle efficiency by influence on the condensation temperature. The air extraction system effectiveness depends on a weather conditions, exactly on the ambient temperature, this raises the question whether it is worth to modernize the hydro ejectors or replace them by a centrifugal vacuum pumps. To establish the vacuum system effectiveness a new innovative mass flow measuring system has been implemented to measure an air-steam mixture flow and the share of the air mass in the mixture. The measuring system is based on a Venturi nozzle supplemented with a temperature drop during the mixture expansion.
Styrene epoxidation over heterogeneous manganese(III) complexes
- Iwona Kuźniarska-Biernacka
- Agata Lisińska-Czekaj
- Dionizy Czekaj
- M Jose Alves
- A. Mauricio Fonseca
- Isabel Correia Neves
2016 Pełny tekst ARCHIVES OF METALLURGY AND MATERIALS
The manganes(III) complex functionalised with 2,3-dihydropyridazine has been encapsulated in the supercages of the NaY zeolite using two different procedures, flexible ligand and in situ complex. The parent zeolite and the encapsulated manganese(III) complexes were screened as catalysts for styrene oxidation by using t-BOOH as the oxygen source in acetonitrile. Under the optimized conditions, the catalysts exhibited moderate activity with high selectivity to benzaldehyde
Styrene-Butadiene Rubber/Modified Ground Tire Rubber Blends Co-Vulcanization: Effect of Accelerator Type
- Krzysztof Formela
- Magdalena Formela
- Sabu Thomas
- Józef Haponiuk
2016 MACROMOLECULAR SYMPOSIA
Ground tire rubber was thermo-mechanically modified with using a co-rotating twin screw extruder. Modification of GTR was conducted in autothermal conditions. Styrene-butadiene rubber and modified ground tire rubber blends were prepared via two-roll milling. Obtained compounds were cured with conventional system (sulfur/vulcanization accelerator ratio was 2:1). During this research three commonly vulcanization accelerators (MBT, TBBS, TMTD) were used. Curing characteristics, static mechanical properties (tensile strength, elongation at break, hardness, resilience), dynamic mechanical properties, swelling degree and thermal properties of obtained SBR/mGTR blends were determined. SBR/modified GTR blends with higher amount of modified GTR shown improvement in tensile strength, on the other hand vulcanization accelerator type had strong influence on curing parameters, tensile strength, elongation at break, swelling degree and glass transition temperature. The best curing and mechanical properties were estimated for SBR/mGTR blend with 50 phr mGTR cured with TMTD accelerator.
Sub-regional service centres in reality and regional planning in Poland = Podregionalne osrodki obsługi w sferze realnej i planowaniu regionalnym w Polsce
- Jacek Sołtys
2016 Pełny tekst PRACE NAUKOWE UNIWERSYTETU EKONOMICZNEGO WE WROCŁAWIU
Sub-regional centres are defined as towns where the services of the sub-regional level are concentrated. In Poland these are such services that can be located in several towns in a voivodeship (region), but not in every capital of a poviat (county). The transformation of civilization has influenced changes in Christaller’s model of settlement network, but re-gularities are still valid. Models derived from Christaller's Central Place Theory have been used not only in describing reality, but also in planning, e.g. in Germany. In Poland, centres established in the spatial development plans for voivodeships are not used as a tool for the localization of services. The issue of sub-regional centres in Poland defined by sets of services has not been researched recently. Also, the role of a hierarchical service model in regional policy has not yet been researched. Thus, the objectives of the presented research were to verify: 1) whether any regularities of a hierarchical model for the localization of services exist at the sub-regional level in Poland, 2) to what extent regional planning in Poland operates according to a hierarchical model of service. Methods of research included: identification and classification of sub-regional centres (apart from metropolitan areas), which were examined on the basis of four kinds of services, and analysis of spatial development plans for voivodeships. Research shows that some towns can be identified as complete or incomplete sub-regional centres (depending on the extent of equipment provided), and that the levels of hierarchical centres established in the regional plans fail to specify whether those centres are in fact service centres.