2019 - Repozytorium publikacji - Politechnika Gdańska

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Effect of selective laser treatment on initiation of fatigue crack in the main part of an undercarriage drag strut
- Anna Bień
- Marek Szkodo
- Jerzy Doberski
- Bartłomiej Karpiński
2019 Pełny tekst Chinese Journal of Aeronautics
This paper presents the results of material characterization and a fatigue test conducted for a laser-re-melted drag strut used in an aircraft landing gear. The drag strut was re-melted with a CO2 laser beam. Eight re-melted paths were made in the form of spiral lines along the axis of the drag strut. Next, the drag strut was subjected to variable loads on a testing machine simulating loads occurring when an aircraft lands. The fatigue test showed that the laser-treated drag strut was able to withstand 1700 simulated cycles of landing. This result was 70% better than that obtained for a drag strut with no laser treatment. In order to find the reason for the increase in the number of cycles of simulated landings, tests were carried out using transmission and scanning electron microscopes, a computer microtomograph, an X-ray diffractometer, and a nanoindenter, respectively. Results of the conducted research indicated that the reasons for the increased fatigue life of the laser-treated undercarriage drag strut were both an ultra-fine cellular martensitic microstructure and compressing residual stresses generated during the laser re-melting of the surface layer of the material.
Effect of soil moisture on current-carrying capacity of low-voltage power cables
- Stanisław Czapp
- Filip Ratkowski
2019 Pełny tekst Przegląd Elektrotechniczny
One of the factors affecting current-carrying capacity of underground power cables is the thermal resistivity of soil. Its value in the close proximity of the cable is the most important, and for this reason, in some cases, the local soil is replaced with an another soil type or with a cement-sand mixture. The thermal resistivity of the soil is strongly affected by moisture, and in the case of a cement-sand mixture – as tested by the authors – also by this mixture initial water content. The paper presents results of investigation of soil moisture influence on the soil thermal resistivity, and an analysis of the current-carrying capacity of a low-voltage power cable for various soil parameters, in particular its part directly surrounding the cable.
Effect of solar radiation on current-carrying capacity of PVC-insulated power cables – the numerical point of view
- Stanisław Czapp
- Seweryn Szultka
- Adam Tomaszewski
- Agata Szultka
2019 Pełny tekst Tehnicki Vjesnik-Technical Gazette
Power cables are usually buried in the soil, which results in their relatively high current-carrying capacity. However, there are cases in which the starting/final section of a cable line runs along a pole of an overhead power line. Power cables can be directly exposed to solar radiation then, and this negatively influences their current-carrying capacity as well as estimated life of the cables’ insulation. An analysis of thermal phenomena in PVC-insulated low-voltage power cables, exposed to solar radiation, is conducted in the paper. Current-carrying capacity of an example cable system, for various placements of the cables, is evaluated. The analysis has shown that solar radiation may significantly reduce current-carrying capacity of PVC-insulated cables. A possible method of protection of cables against solar radiation, and its effectiveness, is presented. To investigate the mentioned thermal phenomena, a Computational Fluid Dynamics (CFD) has been used.
Effect of Storage Conditions of Rutile Flux Cored Welding Wires on Properties of Welds
- Aleksandra Świerczyńska
2019 Pełny tekst Advances in Materials Science
The influence of storage locations of two grades of rutile flux cored welding wires on their surface condition and the strength of the welds made with them were studied. Wires were stored in real urban conditions (Gdańsk and Katowice) for 1 month, simultaneously recording changes in conditions: temperature and relative humidity of the environment. Visual tests of wires in the delivered and stored condition as well as visual and tensile strength tests of welds made with them were carried out. It was found that the surface of the wires underwent more intense degradation (atmospheric corrosion) during storage in Katowice than in Gdańsk. Significant difference in tensile strength was observed only for padding welds made using Gdańsk stored wires. The lowest recorded tensile strength value was not lower than the standard requirements for the wires.
Effect of the Catalytic Center on the Electron Transfer Dynamics in Hydrogen-Evolving Ruthenium-Based Photocatalysts Investigated by Theoretical Calculations
- Magdalena Staniszewska
- Stephan Kupfer
- Julien Guthmuller
2019 Pełny tekst Journal of Physical Chemistry C
The light-induced relaxation pathways in the molecular photocatalyst [(tbbpy)2Ru(tpphz)PtCl2]2+ are investigated with time-dependent density functional theory calculations together with the Marcus theory of electron transfer (ET). The calculations show that metal (Ru) to ligand (tpphz) charge transfer (MLCT) triplet states are populated following an excitation in the longer wavelength range of the absorption spectrum, but that an ET toward the catalytic center (PtCl2) from these states is thermodynamically unfavorable, implying that charge separation can only occur via higher energy states in this system. Moreover, low-lying Pt-centered states can be populated and the calculations predict that they can form an excited state equilibrium with MLCT states localized on the tpphz ligand. A comparison with previously reported results for the photocatalyst [(tbbpy)2Ru- (tpphz)PdCl2]2+, based on a PdCl2 catalytic center, is provided in order to decipher the effect of the catalytic center on their respective photochemistry (Staniszewska, M.; Kupfer, S.; Guthmuller, J. Chem.Eur. J. 2018, 24, 11166−11176).
Effect of the North Atlantic Thermohaline Circulation on changes in climatic conditions and river flow in Poland
- Wrzesiński Dariusz
- Marsz Andrzej
- Anna Styszyńska
- Leszek Sobkowiak
2019 Pełny tekst Water
: The purpose of this study is to find connections between the North Atlantic Thermohaline Circulation (NA THC), climate elements, such as cloud cover, precipitation, air temperature, sunshine duration, and relative humidity, and flow of rivers in Poland. The intensity of NA THC was characterized by the DG3L index, which was established to assess changes in the amount of heat transported by NA THC along with the transport of water to the Arctic. The paper explains and discusses the mechanism of impact of the NA THC changeability on the elements of the catchment water balance variability. The positive and negative phases of the DG3L index are strongly correlated with the heat anomalies in the upper layer of the North Atlantic waters. The obtained results show that changes of NA THC have significant impact on weather conditions and selected climate elements in Poland. Statistically significant positive correlations were found between the DG3L index and average annual air temperatures, particularly in April, July, and August, while negative between the DG3L index and the total cloud cover. Consequently, in the years with the positive values of the DG3L index, there are favorable conditions for the strong increase in evaporation and evapotranspiration from the ground surface. This has impact on flow of rivers in Poland, which shows considerable regional differences.
Effect of the welding environment and storage time of electrodes on the diffusible hydrogen content in deposited metal
- Jacek Tomków
- Dariusz Fydrych
- Grzegorz Rogalski
- Jerzy Łabanowski
2019 Pełny tekst REVISTA DE METALURGIA
In the study the glycerin displacement method was used for determination of diffusible hydrogen content in deposited metal. Specimens were welded in the air and in the water with covered rutile electrodes. The first part of the specimens was made immediately after opening the package of the electrodes. The electrodes were then stored in opened packages in laboratory conditions that allowed for contact with the air for three years. After that time, the second part of the samples was made. The results of the measurements of the diffusible hydrogen amount in deposited metal ranged from 32.61 to 39.95 ml/100 g for specimens welded in the air and from 51.50 to 61.34 ml/100 g for specimens made in the water. The statistical analyses were performed in a Statistical software package using the ANOVA module (one-way analysis of variance) with an assumed significance level α = 0.05. The assumption of normality was verified by the Shapiro-Wilk test. The homogeneity of variance was verified by the Levene test. In the next step, post-hoc analyzes were made. The aim was to determine which averages are significantly different. Scheffe, Tukey, NIR Fisher, Newman-Keuls and Duncan tests were used. Possible changes in the diffusible hydrogen content in deposited metal resulting from storage time of electrodes (3 years) were verified by Student’s t-test. All of the statistical analysis shows that the storage time of the electrodes has no significant influence on the diffusible hydrogen content in deposited metal regardless of the welding environment.
Effective configuration of a double triad planar parallel manipulator for precise positioning of heavy details during their assembling process
- Krzysztof Lipiński
2019 Pełny tekst
In the paper, dynamics analysis of a parallel manipulator is presented. It is an atypical manipulator, devoted to help in assembling of heavy industrial constructions. Few atypical properties are required: small workspace; slow velocities; high loads. Initially, a short discussion about definition of the parallel manipulators is presented, as well as the sketch of the proposed structure. In parallel, some definitions, assumptions and equations are presented for the used multibody methodology. The main part of the paper presents results of the numerical tests performed in order to determinate the best work configuration of the proposed structure. It is verified, that with the initially proposed one, not all of the work requirements are satisfied, mainly about the load distribution. Obtained numerical results are confirmed by some diagrammatic simplified analysis of the load distribution. With the same diagrammatic method, alternative configurations are proposed and verified numerically, next. At the end, final configuration is presented as the one satisfying the requirements.
Effective degradation of sulfide ions and organic sulfides in cavitation-based Advanced Oxidation Processes (AOPs)
- Michał Gągol
- Reza Soltani
- Andrzej Przyjazny
- Grzegorz Boczkaj
2019 Pełny tekst ULTRASONICS SONOCHEMISTRY
The paper presents the results of investigations on the effectiveness and reaction rate constants of the oxidation of sulfide ions and organic sulfides in real industrial effluents from the production of bitumens (2000 mg S2- L-1) using hydrodynamic and acoustic cavitation. The content of the effluents was analysed in terms carbon disulfide, dimethyl sulfide, and di-tert-butyl disulfide concentration. A possibility of complete oxidation of sulfides by cavitation alone as well as by its combination with external oxidants such as hydrogen peroxide, ozone or peroxone was demonstrated. The oxidation time for the most effective processes is as little as 15 min. Due to the presence of sulfide ions, the effluents from the production of bitumens were oxidized at a strongly alkaline pH. The results of this study reveal the advantage of performing advanced oxidation processes (AOPs) at a basic pH. The effective degradation of sulfide ions enables performance of further degradation of organic contaminants at an acidic pH, ensuring high efficiency of treatment based, for example, on the Fenton reaction without the risk of release of hydrogen sulfide to the atmosphere. The results of this research are applicable to all kinds of caustic effluents for which the lack of possibility of pH adjustment limits their efficient treatment.
Effective Formula for Impact Damping Ratio for Simulation of Earthquake-induced Structural Pounding
- Seyed Khatami
- Hosein Naderpour
- Rui Barros
- Anna Jakubczyk-Gałczyńska
- Robert Jankowski
2019 Pełny tekst Geosciences
Structural pounding during earthquakes may cause substantial damage to colliding structures. The phenomenon is numerically studied using different models of collisions. The aim of the present paper is to propose an effective formula for the impact damping ratio, as a parameter of the impact force model used to study different problems of structural pounding under seismic excitations. Its accuracy has been verified by four various approaches. Firstly, for the case of collisions between two structural elements, the dissipated energy during impact has been compared to the loss of kinetic energy. In the second stage of verifications, the peak impact forces during single collision have been analyzed. Then, the accuracy of different equations have been verified by comparing the impact force time histories for the situation when a concrete ball is dropped on a rigid concrete surface. Finally, pounding between two structures during earthquakes has been studied. The results of the analysis focused on comparison between dissipated and kinetic energy show relatively low errors between calculated and assumed values of the coefficient of restitution when the proposed equation is used. In addition, the results of the comparison between experimentally and numerically determined peak impact forces during single collision confirm the effectiveness of the approach. The same conclusion has been obtained for the whole impact time history for collision between a ball and a rigid surface. Finally, the results of the comparative analysis, conducted for pounding between two structures during an earthquake, confirm the simulation accuracy when the proposed approach is used. The above conclusions indicate that the proposed formula for impact damping ratio, as a parameter of impact force model for simulation of earthquake-induced structural pounding, is very effective and accurate in numerical simulations in the case of different scenarios.
Effective Friction Angle Of Deltaic Soils In The Vistula Marshlands
- Kamila Międlarz
- Jakub Konkol
- Lech Bałachowski
2019 Pełny tekst Studia Geotechnica et Mechanica
This article presents the results of laboratory tests on soft, normally consolidated soils from the Vistula Marshlands. Samples of high-plasticity organic soils (muds) taken from 3.2–4.0 m and 9.5–10.0 m depth, as well as peat deposit at 14.0 m, are analysed. Presented case study confirms the applicability of the Norwegian Institute of Technology (NTH) method based on Cone Penetration Tests (CPTU) and allows for a conservative estimation of effective friction angle for muds. The plastification angle equal to 14.5° for organic silt, applied in the modified NTH method, fits well the triaxial test (TX) results. Moreover, the dilative-contractive behaviour according to the CPTU soil classification based on the Robertson’s proposal from 2016 corresponds well with volumetric changes observed in the consolidated drained triaxial compression tests. The internal friction angles of the Vistula Marshlands’ muds and peats are lower in comparison with the database of similar soft soils.
Effective yttrium based coating for steel interconnects of solid oxide cells: Corrosion evaluation in steam-hydrogen atmosphere
- Sebastian Molin
- Å.h. Persson
- T.l. Skafte
- A.l. Smitshuysen
- S.h. Jensen
- K. H. Andersen
- H. Xu
- Ming Chen
- Peter Vang Hendriksen
2019 JOURNAL OF POWER SOURCES
This work describes manufacture, analysis and test of a new well conducting corrosion-protection coating that can be applied on steel types with high chromium content. Electrolytic deposition of yttrium salts is used to form thin (<100 nm) coatings on both flat steel sheets (material: Crofer 22 APU) and its properties are proven on woven wire-meshes (materials from two different sources: SUS316 and SUS316L). The oxide scale on the coated Crofer 22 APU sheet remains intact after 2000 h operation at 750 °C in H2 with 90% H2O. The corrosion rate at 750 °C of the coated Crofer 22 APU sheets is compared with that of uncoated samples and of samples with a commercial magneton sputtered CGO coating revealing that the coatings reduce the parabolic rate constant characteristic of the corrosion by a factor of 10 and 20 for the CGO and the Y, respectively.
Effects of electrophoretic deposition times and nanotubular oxide surfaces on properties of the nanohydroxyapatite/nanocopper coating on the Ti13Zr13Nb alloy
- Michał Bartmański
- Andrzej Zieliński
- Magdalena Jażdżewska
- Joanna Głodowska
- Pamela Kalka
2019 CERAMICS INTERNATIONAL
Load-bearing implants are developed with a particular emphasis placed on an application of ceramic hydroxyapatite coatings in order, to enhance the bioactivity of titanium implants and to shorten the healing time. Therefore, thin, fully crystalline coatings that are, highly adhesive, hydrophilic and demonstrating antibacterial properties are ly looked for. The aim of this research was to develop and characterize the properties of (nano)hydroxyapatite coatings implemented with nanocopper particles and obtained by the electrophoretic method. The deposition was carried out on the Ti13Zr13Nb alloy, either on a bare surface or a nanotubular oxide layer. The deposition was made for 1 or 2 min. The chemical composition, phase composition, coating structure, homogeneity, thickness, nanoindentation and nanomechanical properties, adhesion determined by a nanoscratch test, and wettability measured by a contact angle were investigated. The presence of nanotubular oxide layers caused no significant change in nanoindentation and nanomechanical propertie and an increase in adhesion strength and a decrease in the contact angle. The increase in deposition time resulted in an increased thickness, a decreased hardness, an increased adhesion strength and wettabilty. The observed effects in the composite (nano)HAp/Cu – (nano)TiO2 coatings are attributed to the change in the structure of coatings following the increasing deposition time and coating thickness.
Effects of mechanical stress on electrical arameters and noise of supercapacitors
- Arkadiusz Szewczyk
- Łukasz Lentka
- Janusz Smulko
2019 Pełny tekst
Results of noise and electrical parameters measurements of prototype electrochemical double layer capacitors (EDLC) are reported at the presence of selected mechanical stress. This issue is of great importance due to future applications in wearable technology. The measurement results are compared, and we may conclude than flicker noise is more sensitive to any stress than other considered electrical parameters.
Effects of Na+, K+ and B3+ Substitutions on the Electrical Properties of La10Si6O27 Ceramics
- Sea-Fue Wang
- Yung-Fu Hsu
- Yi-Le Liao
- Ting-Ting Yang
- Piotr Jasiński
2019 JOURNAL OF ELECTRONIC MATERIALS
Doping of Na and K at La sites and of B at Si site in La10Si6O27 with oxyapatite structure and fabrication of their ceramics were made by the solid-state reaction method. It was found that partial substitution of Na+ and K+ on La sites decreased the sinterability of the La10Si6O27 based ceramics, whereas partial substitution of B3+ on the Si site improved the sinterability. Na+ and K+ substitutions in La10−xNaxSi6O27−x and La10−xKxSi6O27−x can suppress second-phase La2SiO5 formation, and, in this study, as the x value of the two substitutions reached 0.7 and 0.5, respectively, the La2SiO5 phase disappeared. Doping of Na+, K+, and B3+ all displayed the hindering effect of grain growth during sintering. Compositions of La9.3Na0.7Si6O26.3, La9.5K0.5Si6O26.5, and La10Si5.5B0.5O26.75 revealed the highest electrical conductivity in each system. La10Si5.5B0.5O26.75 ceramic sintered at 1575°C showed the highest electrical conductivity at temperatures above 600°C among all the apatite ceramics evaluated. The electrical conductivities of La10Si5.5B0.5O26.75 at 700°C and 800°C reported 0.011 S cm−1 and 0.024 S cm−1, respectively, which are superior or comparable to previous studies, and their activation energies for conduction were calculated to be 0.80 eV.
Effects of Na+, K+ and B3+ Substitutions on the Electrical Properties of La10Si6O27 Ceramics
- Sea-Fue Wang
- Yung-Fu Hsu
- Yi-Le Liao
- Ting-Ting Yang
- Piotr Jasiński
2019 ECS Transactions
Doping of Na and K at La sites and of B at Si site in La10Si6O27 with oxyapatite structure and fabrication of their ceramics were made by solid-state reaction method. It was found that partial substitution of Na+ and K+ on La sites decreased the sinterability of the La10Si6O27 based ceramics, whereas partial substitution of B3+ on Si site imporved the sinterability. Na+ and K+ substitutions in La10-xNaxSi6O27-x and La10-xKxSi6O27-x were found to suppress second-phase La2SiO5 formation. La10Si5.5B0.5O26.75 ceramic sintered at 1575ºC showed the highest electrical conductivity at temperatures above 600ºC among all the apatite ceramics evaluated. The electrical conductivities of La10Si5.5B0.5O26.75 at 700ºC and 800ºC reported 0.011 and 0.024 S cm-1, respectively, which are superior or comparable to previous studies, and their activation energies for conduction were calculated to be 0.80 eV.
Effects of n-butanol presence, inlet loading, empty bed residence time and starvation periods on the performance of a biotrickling filter removing cyclohexane vapors from air
- Piotr Rybarczyk
- Bartosz Szulczyński
- Milena Gospodarek
- Jacek Gębicki
2019 Pełny tekst CHEMICAL PAPERS
This paper presents the results of investigations on the removal of cyclohexane vapors from air using a peat-perlite packed biotrickling filter. Effects of basic process parameters i.e. IL (inlet loading) and EBRT (empty bed residence time) as well as introduction of n-butanol to the treated air stream and starvation periods on the process performance were evaluated. The results show that the introduction of hydrophilic n-butanol results in an enhanced removal of hydrophobic cyclohexane comparing to the experiments where only cyclohexane was treated. Additionally, the biotrickling filter performance after the starvation events is regained to more extent for mixed system than for the single cyclohexane. A novel and interesting element of the paper is the application of an electronic nose for the process monitoring. Obtained results are discussed in the perspective of an influence of the presence of a compound with different affinity to aqueous phase on the removal efficiency of the compound with opposite chemical properties.
Effects of Road Infrastructure on Pedestrian Safety
- Marcin Budzyński
- Lucyna Gumińska
- Kazimierz Jamroz
- Tomasz Mackun
- Piotr Tomczuk
2019 Pełny tekst IOP Conference Series: Materials Science and Engineering
The objective of the work was to identify risks for pedestrians that involve road infrastructure and roadside and to define how selected elements of geometry and traffic layout affect driver behaviour (speed on approaching pedestrian crossings). The results have helped to formulate recommendations on pedestrian crossing design. The research included an analysis of 2013-2017 statistics to identify the circumstances and causes of pedestrian accidents. Field work at about 2,000 unsignalized pedestrian crossings was the basis for assessing the safety of these crossings. Assessment criteria were selected and a safety classification was made with specific recommendations made for possible treatments. More field work was designed to measure speeds near pedestrian crossings in three cases: no pedestrians in the crossing area, a pedestrian is approaching a crossing, a pedestrian is waiting to cross the road. The study was conducted in different areas (city, transit roads passing through small towns, non-built-up areas) for different cross-sections (one carriageway and two lanes –1x2, two carriageways with two or three lanes each –2x2, 2x3, one carriageway and four lanes –1x4). The study also looked at speed limits –50 and 70 km/h. The share of drivers giving way to pedestrians waiting to cross was also assessed. Pedestrians were surveyed and asked about how safe they feel crossing the road. The survey also asked drivers about driver behaviour and use of speed management measures.Statistical analyses show the circumstances and causes of pedestrian accidents
Efficiency and proportions of waste tyre pyrolysis products depending on the reactor type—A review
- Witold Lewandowski
- Katarzyna Januszewicz
- Wojciech Kosakowski
2019 Pełny tekst JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
This article discusses the current use of different pyrolytic reactors, their constructions and operating principles regarding the yields of main products of waste tyre pyrolytic recycling. Whether one makes a larger or smaller profit, or even a loss due to a surcharge being levied on waste tyre recycling, depends on the sale of the pyrolysis products (gas, char, oil), the proportions and market prices of which differ. The cheapest is gas, which can be used as a source of technological heat of energetically self-sufficient pyrolysis or after purification, can be burned in a boiler and converted into heat or electricity. Raw char is not expensive either. It requires upgrading and then, as carbon black, can be re-used for the production of tyres or in the form of improved carbon can be used as an absorber or catalyst. The most expensive is oil, containing mainly aromatic compounds, on the condition that it will not be burned as diesel or liquid fuel. Hence, the oil yields obtained in various types of pyrolysers are given. This review of pyrolysis reactors is organised according to the criterion of charge movement in the reactor and the means of bringing this about. Depending on the method and speed of movement of the load in reactors, they are classified as fixed-bed and movable-bed reactors. The latter group is subdivided, depending on the method of inducing this movement, into pneumatic (bubbling, spouted, circulating or transport fluidised beds), mechanical (rotary kiln, rake, auger, ablative, stirred) reactors and reactors in which the charge moves under gravity. This review focuses on the construction and operating principles of the reactors and the yields of the products of pyrolytic thermal decomposition of scrap tyres. The summary and comparison of main product yields (oil/ gas/coal) obtained in different reactors and by different authors, presented in graphical and tabular form, constitute a summary and supplement to this work.
Efficient Finite Element Analysis of Axially Symmetrical Waveguides and Waveguide Discontinuities
- Małgorzata Warecka
- Rafał Lech
- Piotr Kowalczyk
2019 Pełny tekst IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
A combination of the body-of-revolution and finite element methods is adopted for full-wave analysis of waveguides and waveguide discontinuities involving angular field variation. Such an approach is highly efficient and much more flexible than analytical techniques. The method is performed in two different cases: utilizing a generalized impedance matrix to determine the scattering parameters of a single waveguide section and utilizing periodic boundary conditions without sources. In order to confirm the validity and efficiency of both approaches, a few examples of axially symmetrical structures have been analyzed. The obtained results are compared to those obtained from commercial software and available in the literature.