2013 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2013

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Study of the formation of calcareous deposits on cathodically protected steel in Baltic sea water
- Krzysztof Żakowski
- Michał Szociński
- Michał Narożny
2013 Pełny tekst ANTI-CORROSION METHODS AND MATERIALS
Purpose – The purpose of this paper is to investigate whether the sedimentation of calcareous deposits occurs on cathodically protected steel in Baltic sea water. Design/methodology/approach – Steel electrodes were cathodically polarized in natural Baltic sea water at potential þ0.150 V vs Zn electrode in potentiostatic mode. During exposure chronoamperometric measurements were carried out. After the exposure, the electrode’s surface was examined by scanning atomic force microscope (AFM) and by scanning electron microscope (SEM). Deposit composition was examined by energy-dispersive X-ray spectroscopy (EDX). Comparative investigation was carried out in 1 percent NaCl solution (comparable to the salinity of Baltic sea water). Findings – During cathodic polarization in Baltic sea water, non-conducting calcareous deposits developed on steel surface. These deposits significantly lowered the cathodic current demand. Morphology and EDX spectroscopy of the deposit indicated that it was built mainly of aragonite (polymorph of CaCO3). No non-conducting deposits on cathodically protected steel electrodes developed in 1 percent NaCl solution. Originality/value – Composition of Baltic sea water favours the formation of calcareous deposits on cathodically protected steel. Sedimentation is a beneficial and desired phenomenon from the point of view of cathodic protection system of maritime construction as it facilitates polarization. Evolution of calcareous deposits should be taken into account as one of the environmental factors when designing a cathodic protection system.
Study of the Influence of Heat Convection Coefficient on Predicted Performance of a Large Tilting-Pad Thrust Bearing
- Michał Wodtke
- Michel Fillon
- Andreas Schubert
- Michał Wasilczuk
2013 JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
Part of the heat generated by the shearing of the lubricating film during operation of a hydrodynamic bearing is transferred to the bearing components. In the case of the pad, which is usually fully submerged in the lubricating oil, heat is further transferred at the pad free walls to the oil by convection. This mechanism causes a thermal gradient in a pad and, consequently, its thermal deflection. In large hydrodynamic thrust bearings, thermal deflection of the pads is an important phenomenon influencing bearing performance. For such bearings, pad distortion can reach the level of hydrodynamic film thickness and can significantly change the bearing’s properties. In this paper, the study of the influence of the heat convection coefficient on the predicted performance of a large hydrodynamic thrust bearing is presented. Two sets of convection coefficients at the pad free surfaces are investigated with the use of thermo-elasto-hydrodynamic (TEHD) calculations. An analysis is carried out for the Itaipu hydro turbine thrust bearing with the outer diameter equal to 5.2 m, which is one of the biggest hydro power plants in the world. The results of the theoretical predictions are compared to the measured data collected during bearing operation.
Study on deformed steel columns subjected to impact load due to soft-storey failure in buildings during earthquakes
- Wojciech Migda
2013
The so called soft-storey failure is one of the most typical types of damage induced in buildings as the result of earthquake excitation. It has been observed during ground motions that the failure of an upper soft storey of a structure results in large vertical impact load acting on the lower floors. If the resistance of the structural members of the lower storeys is not sufficient it may further lead to progressive collapse of the whole building substantially intensifying material damages as well as human loses. The main aim of the dissertation is to study the behaviour of steel columns that experience horizontal deformations due to earthquake forces and are additionally subjected to vertical impact load (the effect of the soft-storey failure during ground motion). Furthermore, the response of a multi-storey steel frame building that suffers from a soft-storey failure under real earthquake excitation is also investigated in details. First, the horizontal stiffness degradation of deformed building steel columns subjected to vertical impact has been investigated. Then, the experimental investigation focused on the behaviour of models of deformed steel columns that are additionally subjected to vertical impact load, by dropping the steel sphere from different heights onto the top of the models, has been carried out. The detailed numerical investigation concerning the behaviour of a model of deformed steel column that is additionally subjected to vertical impact load has been studied in the next part of this dissertation. The geometric nonlinearity (large strain analysis) as well as the elasto-plastic material behaviour with the strain rate effect have been considered in the analysis. The accuracy of the numerical model of the specimen has been confirmed by comparing the results of the numerical analysis with the experimental results. Finally, the detailed, nonlinear, three-dimensional numerical analysis using FEM, focused on the behaviour of multi-storey steel frame building that suffers from a soft-storey failure under ground motion excitation, has been conducted. The geometric nonlinearity due to impact and the second order effects as well as the elasto-plastic material behaviour with the strain rate effect have been considered in the numerical analysis.
Studzienka rewizyjna z tworzywa
- Ziemowit Suligowski
2013 Instal
Szczególne wymagania kanalizacyjnych studzienek z tworzyw sztucznych. Specyfika konstrukcji z tworzyw termoplastycznych. Problem wyboru rozwiązania, deklaracja na poziomie Specyfikacji Istotnych Warunków Zamówienia. Kategorie normowe, deklaracja producenta
Styrene Oxidation by Copper(II) Complexes Salen-Type Encapsulated into Nay Zeolite
- Iwona Kuźniarska-Biernacka
- M.a. Carvalho
- I. Correia Neves
- A. Mauricio Fonseca
- Agata Lisińska-Czekaj
- Dionizy Czekaj
2013 Pełny tekst ARCHIVES OF METALLURGY AND MATERIALS
The copper(II) complex with a Schiff-base salen-type ligand has been encapsulated in the nanopores of a NaY zeolite by using two different methodologies, the flexible ligand and in situ complex preparation methods. The encapsulated and non-encapsulated copper(II) complexes were screened as catalysts for styrene oxidation by using TBHP as the oxygen source in acetonitrile solvent. Under the optimized conditions, the catalysts exhibited moderate activity with higher selectivity to benzaldehyde. Both heterogeneous catalysts were found to be reusable after the catalytic cycle, but with some loss of activity.
Successfull urban regeneration project: Gdansk-Letnica district case study
- Elżbieta Urbańska-Galewska
- Magdalena Apollo
2013 Pełny tekst Civil and Environmental Engineering Reports
The paper presents the process of urban regeneration of Gdansk Letnica district, a project that from a very short time perspective can be described as successful. The paper present a brief district's history as well as analysis of circumstances that may have influenced Gdansk authorities' decision of starting an urban regeneration project.
Superconductivity in the Cu(Ir1-xPtx)2Se4 spinel
- Huixia Luo
- Tomasz Klimczuk
- Lukas Müchler
- Leslie Schoop
- Daigorou Hirai
- M. K. Fuccillo
- Claudia Felser
- Robert J. Cava
2013 Pełny tekst PHYSICAL REVIEW B
We report the observation of superconductivity in the CuIr2Se4 spinel induced by partial substitution of Pt for Ir. The optimal doping level for superconductivity in Cu(Ir1-xPtx )2Se4 is x = 0.2, where Tc is 1.76 K. A superconducting Tc vs composition dome is established between the metallic, normal conductor CuIr2Se4 and semiconducting CuIrPtSe4. Electronic structure calculations show that the optimal Tc occurs near the electron count of a large peak in the calculated electronic density of states and that CuIrPtSe4 is a band-filled insulator. Characterization of the superconducting state in this heavy metal spinel through determination of C/ã Tc indicates that it is BCS-like. The relatively high upper critical field at the optimal superconducting composition [Hc2(0) = 3.2 T] is much larger than that reported for analogous rhodium spinels and is comparable to or exceeds the Pauli field (ì0HP ), suggesting that strong spin-orbit coupling may influence the superconducting state. Further, comparison to doped CuIr2S4 suggests that superconductivity in iridium spinels is not necessarily associated with the destabilization of a charge-ordered spin-paired state through doping.
Superkomputerowy system identyfikacji pojazdów na podstawie numerów rejestracyjnych
- Andrzej Sobecki
- Marek Downar
2013 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
Opisano sposób identyfikacji pojazdów na podstawie numerów rejestracyjnych. Scharakteryzowano etapy identyfikacji i wymieniono algorytmy stosowane w ramach implementacji rozwiązania ESIP (Elektroniczny System Identyfikacji Pojazdów). Skuteczność zastosowanych algorytmów porównano z innymi rozwiązaniami dostępnymi na rynku. Opisano wdrożenie rozwiązania na superkomputerze GALERA. System ESIP umożliwia skuteczną identyfikację pojazdów na podstawie materiału wideo.
Supply current signal and artificial neural networks in the induction motor bearings diagnostics
- Tomasz Ciszewski
- Leon Swędrowski
2013
This paper contains research results of the diagnostics of induction motor bearings based on measurement of the supply current with usage of artificial neural networks. Bearing failure amount is greater than 40% of all engine failures, which makes their damage-free operation crucial. Tests were performed on motors with intentionally made bearings defects. Chapter 2 introduces the concept of artificial neural networks. It presents the general structure of a multilayer neural network (Fig.1) and the model of a single neuron (Fig. 2) which explains how to create an output signal (1,2,3). As learning method for created network back-propagation algorithm was chosen. It uses equation (4) for calculating the errors in the k-th layer. As the model data for network learning, DREAM vibration diagnostics system results were used. Chapter 3 describes how the network input data were created. The essence of the algorithm is to choose the right set of weights for each rotor speed. This is innovative solution of this diagnostic problem. Results of this study are shown in Table 1. Equations (6) - (12) describe how each error was counted. Method shown in this paper, after development, can be useful for the industry.
Surface Dielectric Barrier Discharge Plasma Actuators
- E. Moreau
- A. Debien
- N. Benard
- T. N. Jukes
- R. D. Whalley
- K.-S. Choi
- Artur Berendt
- J. Podliński
- J. Mizeraczyk
2013 ERCOFTAC Bulletin
This paper presents a part of the works conducted in the Plasmaero European project (task 1.1) on surface dielectric barrier discharge actuators applied to airflow control. The study is divided into several parts. In the first part, the goal is to enhance the electric wind produced by a typical single DBD actuator by optimization of the active electrode shape. For instance, the use of a thin wire instead of a plate air-exposed electrode has shown that the body force can be increased from 65 to 97 mN/m for a power consumption of 1 W/cm. Secondly, plasma vortex generators are presented. The interaction between the spanwise-directed body force and the oncoming boundary layer is illustrated. In the third part, the interest of using threeelectrode based sliding discharges for largescale applications is highlighted. The final part deals with multi-DBD actuators that result in an increase of the electric wind velocity up to 10.5 m/s. This has been previous limited to about 7 m/s until now.
Surface Structure of Components Created by Stereolitography
- Stefan Dzionk
2013 Solid State Phenomena
Stereolithography is an additive rapid prototyping method. This method is based on the principle of solidifying a liquid photopolymer (resin) by laser radiation. Models obtained with this method are characterized by a specific surface structure called “stairstep effect”. It causes that, the surface should be processed by additional finishing (postprocessing). To minimize the additional machining process, the model should be set in the relation to incremental layers so that the roughness of significant surfaces be optimal.
Swarm Algorithms in Modern Engineering Optimization Problems
- Aleksander Pałkowski
- Grzegorz Redlarski
2013
Complexity of today engineering problems is constantly increasing. Scientists no longer are facing issues, for which simple, mathematical programming methods are sufficient. Issues like autonomic vehicle navigation or classification are considered to be challenging, and although there exist valid means to solve them, in some cases there still is some place for improvement. With emergence of a new type of optimization techniques – the swarm algorithms – new possibilities for dealing with those problems had risen. This article presents examples of successful implementation of swarm algorithms (i.e., the River Formation Dynamics and the Modified Cuckoo Search algorithms) into modern engineering optimization problems. Properties of the swarm algorithms made it possible to solve complex, multidimensional problems faster and more efficient than other comparable techniques.
Switched-capacitor DC-DC converters in arbitrary switching mode - topologically derived resistive models based on incremental graph approach.
- Marek Makowski
2013 Elektronika : konstrukcje, technologie, zastosowania
In the preceding paper we reviewed some of modeling approaches aimed at systematic formulation and solution of switched capacitor DC-DC converters. In our review, special attention was paid to computationally efficient and mathematically elegant methods. In so doing we had tried to demonstrate the virtues of unified Incremental Graph (IG) approach. Incremental Graph is, in concept, a tool originally created for analysis and synthesis of electrically degenerated energy conservative networks. We focused, in that former work, on typical conditions, i.e. two-phase converters in slow switching limit (SSL) mode only. In particular, we showed that both voltage gains and charge gains are easily determined on pure topological basis, in terms of IG. The results obtained directly led to a formula for output resistance. The approach is dedicated to SC DC-DC converters and provides a simple means for lossless and lossy model derivation. There, in prediction of further extensions and applications, we promptly communicated our research on models with dependence on duty cycle D and parasitics. In our latest note and in the present article we consequently use topological matrix-based methods instead of well adopted charge and power balance.
Symulacja komputerowa obiektu dynamicznego na przykładzie biogazowni
- Emilian Piesik
- Tomasz Barnert
- Marcin Śliwiński
2013 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
W artykule przedstawiono symulator czasu rzeczywistego biogazowni rolniczej. Przedstawiony symulator obejmuje obiegi biomasy, biogazu a także obieg grzewczy wraz z systemem sterowania urządzeniami układów biogazowni oraz wizualizacją procesów. Badania koncentrowały się na wykonaniu symulatora, który odzwierciedla istniejące instalacje. Oprogramowaniem służącym do symulacji jest system CFD (Computational Fluid Dynamics) dający możliwość symulacji obiegów grzewczych, przepływu medium a także systemów sterowania. Przedstawiona symulacja może posłużyć jako narzędzie do analizy stanów awaryjnych. Wyniki symulacji pozwalają na optymalizowanie realizowanego obiektu pod względem produkcji lub optymalizowania kosztów budowy. Symulator tworzy podstawę szkoleniową dla kadry operatorskiej.
Symulator szybkich procesów dynamiki reaktora jądrowego wodno ciśnieniowego
- Kazimierz Duzinkiewicz
- Arkadiusz Cimiński
- Łukasz Michalczyk
2013 Pełny tekst Pomiary Automatyka Robotyka
Artykuł przedstawia symulator dynamiki reaktora jądrowego (RJ) zbudowany w oparciu o punktowe modele matematyczne procesów reaktora typu wodnego ciśnieniowego (ang. Pressurized Water Reactor – PWR) i zaimplementowany w środowisku MATLAB/Simulink. Symulator wykorzystywany jest obecnie jako narzędzie pomocne w dydaktyce i wstępnych badaniach w zakresie energetyki jądrowej na Politechnice Gdańskiej. W pierwszej części artykuł Autorzy skupili się na szybkich procesach i szybkich oddziaływaniach regulacyjnych, czyli kinetyce neutronów, wymianie ciepła w obszarze rdzenia reaktora oraz regulacji kasetami sterującymi. Model obejmuje efekty reaktyw-nościowe wpływające na procesy kinetyki neutronów wynikające ze zmiany stanu termicznego rdzenia oraz położenia kaset regulacyjnych. W drugiej części artykuł zawiera przedstawienie cech funkcjonalnych symulatora.
Synergistic effect of multi walled carbon nanotubes and reduced graphene oxides in natural rubber for sensing application
- Deepalekshmi Ponnamma
- Kishor Kumar Sadasivuni
- Michał Strankowski
- Qipeng Guo
- Sabu Thomas
2013 SOFT MATTER
Utilizing the electrical properties of polymer nanocomposites is an important strategy to develop high performance solvent sensors. Here we report the synergistic effect of multi walled carbon nanotubes (MWCNTs) and reduced graphene oxide (RGO) in regulating the sensitivity of the naturally occurring elastomer, natural rubber (NR). Composites were fabricated by dispersing CNTs alone and together with exfoliated RGO sheets (thermally reduced at temperatures of 200 and 600 C ) in NR by a solution blending method. RGO exfoliation and the uniform distribution of fillers in the composites were studied by atomic force microscopy, Fourier transformation infrared spectroscopy, X-ray diffraction, transmission electron microscopy and Raman spectroscopy.
Synteza i właściwości fizyko-chemiczne polimerowych mikrosfer zawierających ugrupowania pirolidonowe
- Małgorzata Maciejewska
- Joanna Osypiuk-Tomasik
- Katarzyna Księżniak
2013 ZESZYTY NAUKOWE POLITECHNIKI RZESZOWSKIEJ, SERIA: CHEMIA
Intensywny rozwój nauki i techniki, a w konsekwencji także przemysłu stwarza ogromne zapotrzebowanie na nowe materiały. Stosowane tradycyjnie od stuleci kamień, drewno, bawełna czy stal zostają zastąpione przez ich polimerowe odpowiedniki. Wśród ogromnej rzeszy materiałów polimerowych szczególną pozycję zajmują polimerowe mikrosfery [1]. Są one wykorzystywane jako specyficzne sorbenty, nośniki leków, katalizatory, wypełnienia kolumn do HPLC, GC, SPE. Większość handlowo dostępnych i powszechnie stosowanych polimerowych adsorbentów wykazuje silnie hydrofobowy charakter, znacznie ograniczający spektrum ich zastosowań. Z tego powodu trwają intensywne prace nad syntezą bardziej polarnych materiałów. Wśród wykorzystywanych w tym celu monomerów szczególne miejsce zajmują związki zawierające ugrupowania pirolidonowe. Są one nietoksyczne, biokompatybilne, wykazują duże zdolności kompleksujące [2]. W niniejszej pracy prezentujemy syntezę i analizę właściwości fizyko-chemicznych porowatych mikrosfer zawierających ugrupowania pirolidonowe otrzymanych techniką suspensyjną. Ugrupowania pirolidonowe zostały wprowadzone w sieć polimerową w wyniku bezpośredniej reakcji z 1-winylo-2-pirolidonem (VP) z dimetakrylanem glikolu etylenowego (DMGE) oraz poprzez modyfikację pirolidonem grupy epoksydowej kopolimeru dimetakrylanu glikolu etylenowego z metakrylanem glicydylu (GMA).
Syntheses, spectroscopic and structural properties of phenoxysilyl compounds: X-ray structures, FT-IR and DFT calculations
- Agnieszka Jabłońska
- Łukasz Ponikiewski
- Krzysztof Ejsmont
- Aleksander Herman
- Anna Dołęga
2013 JOURNAL OF MOLECULAR STRUCTURE
The reaction of silicon disulfide with alkylphenols leads to tetraphenoxysilane, cyclodisilthiane and silanethiol. The products of the reaction of silicon disulfide with phenols are characterized by FT-IR, NMR, X-ray diffraction and DFT calculations. The intramolecular interactions in the compounds are mainly XH---π (X = C, S) whereas the intermolecular interactions are either very weak CH---π/CH---O contacts found in aryloxysilane or electrostatic dipole–dipole attraction in cyclodisilthiane and silanethiol. The S–H---π interactions in the obtained silanethiol are analyzed with the use of DFT/GGA BLYP-D XC potentials.
Synthesis and biological activity of mycophenolic acid-amino acid derivatives
- Dorota Iwaszkiewicz-Grześ
- Grzegorz Cholewiński
- Agata Kot-Wasik
- Piotr Trzonkowski
- Krystyna Dzierzbicka
2013 Pełny tekst EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
In search of new immunosuppressants, mycophenolic acid (MPA) was coupled with amino acid methyl esters followed by hydrolysis to analogs bearing free carboxylic groups. The obtained compunds were tested in vitro as growth inhibitors of lymphoid cell line (Jurkat) and human peripheral blood mononuclear cells (PBMC) from healthy donors. According to obtained results recovering of free carboxylic group increased their activity. Additionally, the cytotoxic properties depends on the substituent and configuration at chiral center in amino acid unit. Three derivatives revealed higer potency than parent MPA.
Synthesis and characterization of novel renewable polyesters based on 2,5-furandicarboxylic acid and 2,3-butanediol
- Erik Gubbels
- Lidia Jasińska-Walc
- Cor E. Koning
2013 JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
Novel polyesters from 2,5-furandicarboxylic acid or 2,5-dimethyl-furandicarboxylate and 2,3-butanediol have been synthesized via bulk polycondensation catalyzed by titanium (IV) n-butoxide, tin (IV) ethylhexanoate, or zirconium (IV) butoxide. The polymers were analyzed by size exclusion chromatography, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy (FTIR), matrix-assisted laser ionization-desorption time-of-flight mass spectrometry, electrospray ionization time-of-flight mass spectrometry, electrospray ionization quadruple time-of-flight mass spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. Fully bio-based polyesters with number average molecular weights ranging from 2 to 7 kg/mol were obtained which can be suitable for coating applications. The analysis of their thermal properties proved that these polyesters are thermally stable up to 270-300 °C, whereas their glass transition temperature (Tg) values were found between 70 and 110 °C. Furthermore, a material was prepared with a molecular weight of 13 kg/mol, with a Tg of 113 °C. This high Tg would make this material possibly suitable for hot-fill applications