2016 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2016

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Influence of laser processing of the low alloy medium carbon structural steel on the development of the fatigue crack
- Marek Szkodo
- Anna Bień
2016 Full text SURFACE & COATINGS TECHNOLOGY
The paper contains the results of the structural analysis, hardness tests and fatigue tests conducted for the medium carbon structural steel with low content of Cr and Ni after its processing with CO2 laser beam. Pre-cracks were made in the round compact tension (RCT) specimen used for fatigue test. Next, four paths, parallel to each other, were melted on both sides of the samples using a laser beam. The paths were perpendicular to the direction of the axis of the cut notch. The first melted path ran at a distance of about 2.5 mm from the pre crack tip. Fatigue test results were compared with the sample which was not subjected to laser treatment. The fatigue tests showed that the sample with no laser treatment fractured after 270,000 cycles and the laser treated sample was able to withstand 7.2 million cycles for the same load and during this time the crack length increased only 0.4 mm. Hardness tests to estimate the residual internal stresses in the melted zone, in the heat affected zone (HAZ) and in the native material were carried out using nanoindenter. It was shown that compressive residual stress, in native material, close to HAZ in half-length of the melted path, just before the front of the crack, was 1165 MPa. These residual stresses contribute to the stopping of the development of the fatigue crack. It was also shown that the longitudinal manganese sulfide inclusions reduce crack development rate probably by blunting the crack blade.
INFLUENCE OF LOAD AND INFLATION PRESSURE ON THE TYRE ROLLING RESISTANCE
- Jerzy Ejsmont
- Stanisław Taryma
- Grzegorz Ronowski
- Beata Świeczko-Żurek
2016 Full text INTERNATIONAL JOURNAL OF AUTOMOTIVE TECHNOLOGY
Tyre load and inflation pressure are important factors controlling rolling resistance of road vehicles. The article presents results obtained in the Technical University of Gdańsk during laboratory and road measurements of different car tyres rolling on different pavements. The knowledge of rolling resistance characteristics is important for modelling car dynamics as well as fuel consumption. It is also necessary to establish proper test conditions in the future standardized on-road method of measuring rolling resistance. The results indicate that while an increase of load always leads to the increase of rolling resistance force, the influence on Coefficient of Rolling Resistance is more complicated and unpredictable. They also indicate that tyres with high rolling resistance are more sensitive to inflation pressure changes than low rolling resistance tyres.
Influence of local bush wear on water lubricated sliding bearing load carrying capacity
- Wojciech Litwin
2016 Full text TRIBOLOGY INTERNATIONAL
One of main problems concerning water-lubricated bearings is their durability. There are known cases of bearings with life time measured in decades, and some, whose refurbishment was necessary just days after start-up. Obtaining stable fluid film friction plays key role in the durability of these bearings. Unfortunately, their load-carrying capacity is limited due to water's low-viscosity. The conducted experimental research demonstrated that in water-lubricated bearing working under fluid lubrication regime, noticeable bush wear occurred at the edges. Detailed analysis of this phenomenon made it possible to propose a method for calculating load capacity of sliding bearings which provides for local bush wear.
INFLUENCE OF MEASURING CONDITIONS ON TYRE/ROAD NOISE
- Jerzy Ejsmont
- Berge Truls
- Beata Świeczko-Żurek
2016
A decisive factor for the development of tyres and road surfaces is the ability to conduct representative and reproducible measurements of selected characteristics related to the interaction of tyres and road surfaces. In terms of tyre/road noise measurements in Europe two methods described in ISO/FDIS 11819-2 and ECE Regulation No.117 are used. The latter is compulsory for assigning the tyre noise labels. The methodologies differ in both load and tyre inflation pressure, positioning of microphones (on-board versus stationary) and distance from the microphones to the test tyres. Within the Polish-Norwegian project LEO two research institutions - SINTEF, Norway and Technical University of Gdańsk, Poland conducted a series of road and laboratory tests to determine the effects of measuring methodology, inflation pressure and tyre load as well as road pavement on noise levels and sound spectra. The obtained results were also compared with the information stated on the tyres’ labels. Analysis of the results indicates that changing test parameters such as load and inflation pressure has an important impact on the noise emitted by tested tyres. It was also found that the tyre/road noise measured on typical European road surfaces correlates very poorly with the noise labels of tyres. This observation puts into question the correctness of the procedures described in Regulation No 117. It seems that the methodology for determining noise values, which are the basis for the labelling, should be substantially amended and should be based on one of the typical road pavements.
Influence of metallic porous microlayer on pressure drop and heat transfer of stainless steel plate heat exchanger
- Jan Wajs
- Dariusz Mikielewicz
2016 Full text APPLIED THERMAL ENGINEERING
The experimental analysis of passive heat transfer intensification in the case of plate heat exchanger has been carried out. The metallic porous layer was created on the heat transfer surface of analyzed unit. The experiment was accomplished in two stages. In the first stage the commercial stainless steel gasketed plate heat exchanger was investigated, while in the second one – the identical heat exchanger but with the modified heat transfer surface. The direct comparison of thermal and flow characteristics between both devices was possible due to the assurance of equivalent conditions during the experiment. Equivalent conditions mean the same volumetric flow rates and the same media temperatures at the inlet of heat exchangers in the corresponding measurement series. Experimental data were collected for the single-phase convective heat transfer in the water-ethanol configuration. The heat transfer coefficients were determined using the Wilson plot method. The results showed the advantages of such heat exchanger construction in some flow ranges and for some fluids.
Influence of nanoparticle concentration on convective heat transfer of water-Al2O3 nanofluids inside horizontal tubes
- Janusz Cieśliński
- Przemysław Kozak
2016 Applied Mechanics and Materials
Nanofluids came to be seen as a new generation of coolants, especially in single-phase systems. Conducted experiments indicate that the increase in thermal conductivity is not the only reason for the intensification of heat transfer when using nanofluids. Preliminary results of the experimental investigation of the forced convection heat transfer of water-Al2O3 nanofluids inside stainless steel tube with 8 mm internal diameter and 2000 mm length are presented. The Reynolds number range encompasses laminar as well as turbulent flows.
Influence of nanoparticle concentration on thermal properties of thermal oil-MWCNT nanofluid
- Janusz Cieśliński
- Katarzyna Krygier
- Sławomir Smoleń
2016 Applied Mechanics and Materials
Results of the measurements of dynamic viscosity, thermal conductivity, electrical conductivity and pH of thermal oil-MWCNT (TO-MWCNT) nanofluid have been presented. Nanoparticles were tested at the concentration of 0.001%, 0.005%, 0.01%, 0.05%, and 0,1% by weight. Thermal oil (TO) was selected as a base liquid, because of possible application in ORC systems as an intermediate heating agent. Multi-walled carbon nanotubes were used as nanoparticles because of their enormous thermal conductivity. The results obtained for the tested nanofluids were compared with predictions made by use of existing models for liquid/solid particles mixtures.
Influence of Nitriding and Laser Remelting on Properties of Austenitic Stainless Steel Type X10CrNi18-8 and Cavitation Erosion Resistance
- Artur Sitko
- Marek Szkodo
- Stanisław Kucharski
2016 Full text Advances in Materials Science
The paper presents properties of surface layers. Surface layers were obtained by using low temperature glow–discharge nitriding process and laser remelting carried out on austenitic stainless steel type X10CrNi18-8. Investigations were done by using an Ultra Nanoindentation Tester (UNHT) in the Warsaw Institute of Fundamental Technological Research. The influence of the above mentioned treatments on obtained surface layers is shown. The values of the Vickers hardness (HV), the irreversible indentation work (Wir), the reversible work (We) and the maximum depth (hmax) during indentation were determined using the method proposed by Oliver and Pharr [1]. On the basis of mechanical properties, the elasticity (Ie) and ductility (Iir) indexes were calculated. Moreover, microstructure cross-section of the austenitic stainless steel after nitriding process and laser remelting was observed using a scanning electron microscope. Cavitation test was performed at a vibratory rig with stationary specimen. On the basis of erosion curves the cavitation resistance was evaluated. Influence of Nitriding and Laser Remelting on Properties of Austenitic Stainless Steel Type X10CrNi18-8 and Cavitation Erosion Resistance. Available from: https://www.researchgate.net/publication/305842249_Influence_of_Nitriding_and_Laser_Remelting_on_Properties_of_Austenitic_Stainless_Steel_Type_X10CrNi18-8_and_Cavitation_Erosion_Resistance [accessed Dec 2, 2016].
Influence of Processing Conditions on Crystal Structure of Bi6Fe2Ti3O18 Ceramics
- Agata Lisińska-Czekaj
- Martyna Lubina
- Dionizy Czekaj
- Michał Rerak
- Barbara Garbarz-Glos
- Wojciech Bąk
2016 Full text ARCHIVES OF METALLURGY AND MATERIALS
Aim of the present research was to apply a solid state reaction route to fabricate Aurivillius-type ceramics described with the formula Bi6Fe2Ti3O18 (BFTO) and reveal the influence of processing conditions on its crystal structure. Pressureless sintering in ambient air was employed and the sintering temperatures were 850 and 1080 °C. It was found that the fabricated BFTO ceramics were multiphase ones. They consisted of two Bim+1Fem-3Ti3O3m+3 phases, namely the phase with m=5 (i.e. the stoichiometric phase) and m=4 (i.e. the phase with a reduced number of layers in the slab). Detailed X-ray diffraction patterns analysis showed that both phases adopted the same orthorhombic structure described with Fmm2 (42) space group. The ratio of weight fractions of the constituent phases (m=5): (m=4) was ~30:70.
Influence of Protonation State on the Excited State Dynamics of a Photobiologically Active Ru(II) Dyad
- Christian Reichardt
- Tariq Sainuddin
- Maria WäCHTLER
- Susan Monro
- Stephan Kupfer
- Julien Guthmuller
- Stefanie Gräfe
- Sherri A. Mcfarland
- Benjamin Dietzek
2016 JOURNAL OF PHYSICAL CHEMISTRY A
The influence of ligand protonation on the photophysics of a ruthenium (Ru) dyad bearing the 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]-phenanthroline (ippy) ligand was investigated by time-resolved transient absorption spectroscopy. It was found that changes in the protonation state of the imidazole group led to changes in the electronic configuration of the lowest lying excited state. Formation of the fully deprotonated imidazole anion resulted in excited state signatures that were consistent with a low-lying intraligand (IL) triplet state. This assignment was supported by time-dependent density functional theory (TDDFT) calculations. IL triplet states have been suggested to be potent mediators of photodynamic effects. Thus, these results are of interest in the design of Ru metal complexes as photosensitizers (PSs) for photodynamic therapy (PDT).
Influence of Sb-substitution on ionic transport in lanthanum orthoniobates
- Sebastian Lech Wachowski
- Aleksandra Dorota Mielewczyk-Gryń
- Krzysztof Zagórski
- Cheng Li
- Piotr Jasiński
- Stephen J. Skinner
- Reidar Haugsrud
- Maria Gazda
2016 Full text Journal of Materials Chemistry A
The results of ionic transport measurements for the lanthanum orthoniobate substituted with 10 and 30 mol% of antimony (LaNb0.9Sb0.1O4 and LaNb0.7Sb0.3O4) are presented and discussed. The influence of calcium co-doping on these properties has also been analysed. It has been shown that for the investigated material protonic conductivity predominates at temperatures up to 800 °C in oxidizing atmospheres under wet conditions. The maximum observed protonic conductivity reaches ∼10−4 S cm−1 at 800 °C (in humidified air); under dry conditions, the increasing influence of oxygen vacancies and holes is detected. Oxygen self-diffusivity has also been analysed by isotopic exchange to investigate the possible diffusion paths.
Influence of Self-Similar Traffic Type on Performance of QoS Routing Algorithms
- Michał Czarkowski
- Sylwester Kaczmarek
- Maciej Wolff
2016 Full text International Journal of Electronics and Telecommunications
Providing a Quality of Services (QoS) into current telecommunication networks based on packet technology is a big challenge nowadays. Network operators have to support a number of new services like voice or video which generate new type of traffic. This traffic serviced with QoS in consequence requires access to appropriate network resources. Additionally, new traffic type is mixed with older one, like best-effort. Analysis of these new and mixed traffic types shows that this traffic is self-similar. Network mechanisms used for delivery of quality of services may depend on traffic type especially from the performance point of view. This paper presents a feasibility study done into the effect of traffic type influence on performance of routing algorithm while the routing algorithm is treated as one of the mechanisms to support QoS in the network.
Influence of separation gap on the response of colliding models of steel structures under seismic and paraseismic excitations
- Barbara Sołtysik
- Robert Jankowski
2016
As a result of high urbanization, the need to erect closely-spaced buildings forces designers to consider collisions between structures taking place during ground motions. Experimental and numerical studies have confirmed that such collisions (often referred to as structural pounding) may cause serious damage to the structural elements and even lead to total collapse of colliding structures. The main reason of earthquake-induced structural pounding, besides insufficient in-between gap size, is related to the differences in stiffness and/or mass of colliding structures. The aim of the study is to present the results of experimental investigation focused on dynamic behavior of closely-separated steel structures under seismic and paraseismic excitations. To perform this study, models of three steel towers, with different dynamic parameters, have been constructed and mounted to the platform of a shaking table. The influence of the size of separation gap (=0 mm; =30 mm; =60 mm) on the response of colliding structures has been investigated. Experimental study confirms that earthquake-induced pounding may lead to significant changes in the structural behavior. The smallest structural response has been observed for the case of zero gap size as well as when the gap size is large enough to prevent pounding.
Influence of Sn and Pb Ions Substitutions on Dielectric Properties of Barium Titanate
- W Bąk
- C. Kajtoch
- S. Ptaszek
- Agata Lisińska-Czekaj
- Dionizy Czekaj
- D. Ziętek
- T. Glos
- B Garbarz-Glos
2016 Full text ARCHIVES OF METALLURGY AND MATERIALS
The results of the microstructural and dielectric measurements of (Ba1-xPbx)(Ti1-xSnx)O3 (BPTSx) (x = 0, 0.05, 0.10, 0.30) polycrystalline samples are presented. The samples were obtained by means of a high temperature synthesis and their expected stoichiometry was confirmed by energy dispersive spectroscopy (EDS) measurements. The dielectric properties of BPTSx were studied with the use of broadband dielectric spectroscopy. The measurements over a wide range of temperature (from 140 K to 600 K) and frequency (from 0.1 Hz to 10 MHz) were performed. The experimental results indicate an influence of Pb ions in a sublattice A and Sn ions in a sublattice B substitution on paraelectric – ferroelectric phase transition parameters. Diffused phase transitions from a paraelectric to ferroelectric state (for x = 0.10 and x = 0.30) were observed. From the electric modulus measurements in the frequency domain the relaxation times and the activation energy were determined
Influence of S-Oxidation on Cytotoxic Activity of Oxathiole-Fused Chalcones
- Marek T. Konieczny
- Anita Bułakowska
- Danuta Pirska
- Wojciech Konieczny
- Andrzej Składanowski
- Michał Sabisz
- Marek Wojciechowski
- Krzysztof Lemke
2016 Chemical Biology & Drug Design
Synthesis, in vitro cytotoxic activity, and interaction with tubulin of oxidized, isomeric 1-(5-alkoxybenzo[d] [1,3]oxathiol-6-yl)-3-phenylprop-2-en-1-ones and 1-(6- alkoxybenzo[d][1,3]oxathiol-5-yl)-3-phenylprop-2-en-1- ones are described. Most of the compounds demonstrated cytotoxic activity at submicromolar concentrations. It was found that oxidation of sulfur atom of the oxathiole-fused chalcones strongly influenced activity of the parent compounds, and that depending on relative position of the sulfur atom in the molecule, the activity was either increased or diminished. For isomers with sulfur atom para to the chalcone carbonyl group, oxidation led to increase in activity, while for isomers with sulfur atom meta to the carbonyl the activity dropped down. It was demonstrated that the compounds interact with tubulin at the colchicine binding site, and the interaction was evaluated using molecular modeling. It was concluded that the observed profound influence of oxidation of the sulfur atom on cytotoxic activity cannot be solely related to interaction of the compounds with tubulin.
Influence of span length and impulse front time on earthing measurement accuracy of power line towers
- Stanisław Wojtas
2016 Full text Przegląd Elektrotechniczny
The article discusses the issue of measuring and assessing the features of power line tower earthings using fast-changing waveform. The study analyses the effect of impulse front time and the line span length on errors made during these measurements using impulse meters. It has been found that the assessment conditions similar to the static measurement results occur for the use of 4 μs current impulses and such procedure is useful for evaluating power line tower earthings.
Influence of temperature on the activity of anammox granular biomass.
- Dominika Sobotka
- Krzysztof Czerwionka
- Jacek Mąkinia
2016 WATER SCIENCE AND TECHNOLOGY
The aim of this study was to determine a short-term and long-term effect of temperature on the anammox rate and determination of temperature coefficients in the Arrhenius and Ratkowsky equations. The short-term effects of temperature on the anammox granular biomass were investigated in batch tests at ten different temperatures in the range of 10–55 °C. The maximum overall nitrogen removal rate of 1.3 gN gVSS−1·d−1 was observed at 40 °C (VSS: volatile suspended solids). The minimum rate, close to 0 gN gVSS−1·d−1, was observed for the limits of the analyzed temperature range (10 and 55 °C). The activity tests carried out at 55 °C showed an irreversible loss of the activity due to the observed biomass lysis. Subsequently to the batch tests, a sequencing batch reactor (SBR) was operated at different temperatures (from 30 to 11 °C) to determine the long-term effects of temperature. The system was successfully operated at 15 °C, but when temperature was decreased to 11 °C, nitrite started to accumulate and the system lost its stability. The temperature coefficient (θ) was 1.07 for the batch tests carried out in the temperature range of 10–40 °C. In contrast, during the long-term SBR operation, substantially different θ had to be estimated for two temperature ranges, 1.07 (T = 15–30 °C) and 1.65 (T = 11–15 °C).
INFORMATION ABOUT DYNAMICS OF THE SEA SURFACE AS A MEANS TO IMPROVE SAFETY OF THE UNMANNED VESSEL AT SEA
- Marek Przyborski
2016 Full text Polish Maritime Research
One of the fundamental states of the sea surface is its heave. Despite of years of the intense scientific inquiry, no clear understanding of the influence of this aspect on the dynamics of the sea environment has emerged. The separation of two nearby fluid elements which one may observed for example as a free floating of small objects on the sea surface (rescuers on the rough sea or small research vessels) is caused by the interaction of different components. On the other hand one may say that the heave of the sea is also a summary interaction of a few components describing the dynamics of the sea. Therefore it is the most important aspect, which influenced the dispersion phenomenon. This observation has important consequences for many different problems as for example conducting Search and Rescue missions and using unmanned ships. We would like to present results of our experiment focused on finding the answer to question about nature of the heave of the sea and its influence on safety of Unmanned Surface Vessels (USV).
Inhomogeneity of low-noise wearing courses evaluated by tire/road noise measurements using the close-proximity method
- Piotr Mioduszewski
- Władysław Gardziejczyk
2016 APPLIED ACOUSTICS
Performing numerous analyses of tire/road noise measurements on low-noise pavements during the last several years, the authors observed significant inhomogeneity of the wearing course in numerous cases, while similar problems were almost non-existent when dense pavements were measured. Three main causes of low-noise pavement inhomogeneity can be defined. The first one is imperfections in the technology used for asphalt mix production and/or errors made during the laying process of the wearing course. The second one is clogging that takes place during the pavement’s service life. The third reason is related to uneven and/or excessive wear of the pavement (raveling and stripping of the aggregate may appear in this case). Findings of analyses of noise data acquired from low-noise pavements (based on 10 m long segments), using the close-proximity (CPX) method, are presented and discussed herein. Significant differences in measured averaged noise levels, up to 1.7 dB, between test sections of opengraded wearing courses that were the same in principle, located on the same road but in different lanes were found when performing CPX measurements. At the same time the test sections of a dense pavement differed by max. 0.5 dB only. The calculated A-weighted sound pressure level variability index Scpx, considered to be an indication of pavement homogeneity, reached the value of 1.69 dB over a 500 m long test section of the porous pavement while the Scpx values for dense pavements were much below 0.5 dB.
Innovative cold-formed GEB section under compression
- Patryk Deniziak
- Małgorzata Gordziej-Zagórowska
- Agnieszka Łukowicz
- Marcin Szczepański
- Wojciech Migda
2016
Cold-formed steel sections extensively affect the modern steel construction industry. Not only are they used as secondary elements like purlins or sheeting, but also they can serve as primary load-bearing members in fabricated steel panels and trusses. A new cross-section called shortly a GEB may serve as that member. However, its existence of the metal building structures industry depends on the exact, optimal dimensional parameters which are associated with its production possibility and ultimate and serviceably limit states criteria. According to the European Standard EN 1993-1-3 every new section shape should be tested to assign the cross sectional deformation behavior and capacity. That is why this innovative profile inter alia was tested for axial compression. The paper reports the results of experimental test and also computational analysis in RFEM software e.g. deformation modes and maximum axial load. Simultaneously, values of cross-section capacity were assigned based on Standards.