2020 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2020

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The impedance of hydrogen oxidation reaction in a proton exchange membrane fuel cell in the presence of carbon monoxide in hydrogen stream
- Kazimierz Darowicki
- Łukasz Gaweł
- Michał Mielniczek
- Artur Zieliński
- Ewa Janicka
- Jurgen Hunger
- L. Jorissen
2020 Full text APPLIED ENERGY
Evaluation of performance of a proton exchange membrane fuel cell, which is affected by carbon monoxide that pollutes the hydrogen stream, was presented. This influence was studied for carbon monoxide concentration of 125–325 ppb, which are close to values specified in ISO 14687:2019 standard. Performed studies provided crucial information for further development of fuel cell as an energy source for automotive application. Impedance with the use of Dynamic Electrochemical Impedance Spectroscopy profile measurements were completed for chosen carbon monoxide concentration under a constant current load and anode impedance variations were determined as a function of the time exposed to carbon monoxide. A method to determine the impedance of hydrogen oxidation was proposed. It was determined how the carbon monoxide surface coverage of anodic catalyst varies as a function of time. The capacitance of the double electrical layer and the charge transfer resistance of anodic reaction are discussed to evaluate them with respect to exposure time and surface coverage. It has been shown that proposed methodology can be used as a universal tool for testing fuel cells for both research and industrial applications, with the overall aim of optimization, monitoring, and diagnostics of the fuel cell.
The In-Depth Studies of Pulsed UV Laser-Modified TiO2 Nanotubes: The Influence of Geometry, Crystallinity, and Processing Parameters
- Łukasz Haryński
- Katarzyna Grochowska
- Piotr Kupracz
- Jakub Karczewski
- Emerson Coy
- Katarzyna Siuzdak
2020 Full text Nanomaterials
The laser processing of the titania nanotubes has been investigated in terms of morphology, structure, and optical properties of the obtained material. The length of the nanotubes and crystallinity, as well as the atmosphere of the laser treatment, were taken into account. The degree of changes of the initial geometry of nanotubes were checked by means of scanning electron microscopy, which visualizes both the surface and the cross-section. The phase conversion from the amorphous to anatase has been achieved for laser-treated amorphous material, whereas modification of calcined one led to distortion within the crystal structure. This result is confirmed both by Raman and grazing incident XRD measurements. The latter studies provided an in-depth analysis of the crystalline arrangement and allowed also for determining the propagation of laser modification. The narrowing of the optical bandgap for laser-treated samples has been observed. Laser treatment of TiO2 nanotubes can lead to the preparation of the material of desired structural and optical parameters. The usage of the motorized table during processing enables induction of changes in the precisely selected area of the sample within a very short time.
The Indicators Assessment of Safety and Functionality of Tram Loops
- Agnieszka Tubis
- Mateusz Rydlewski
- Marcin Budzyński
2020 Full text Journal of KONBiN
The new requirements set for tram loops mean that all stakeholders' expectations regarding their safety and functionality change. This creates a need for new tools for tram loop assessment, which are important interchanges, especially for people living outside the city limits or on their outskirts. The aim of the authors ’research is to create a indicators for assessing the safety and functionality of tram loops. Therefore, the article presents an overview of the research results in the area of tram transport and interchanges safety. Then the proposed indicator assessment for tram loops was described.
The Influence of Camera and Optical System Parameters on the Uncertainty of Object Location Measurement in Vision Systems
- Jacek Skibicki
- Anna Golijanek-Jędrzejczyk
- Ariel Dzwonkowski
2020 Full text SENSORS
The article presents the influence of the camera and its optical system on the uncertainty of object position measurement in vision systems. The aim of the article is to present the methodology for estimating the combined standard uncertainty of measuring the object position with a vision camera treated as a measuring device. The identification of factors affecting the location measurement uncertainty and the determination of their share in the combined standard uncertainty will allow determining the parameters of the camera operation, so that the expanded uncertainty is as small as possible in the given measurement conditions. The analysis of the uncertainty estimation presented in the article was performed with the assumption that there is no influence of any external factors (e.g., temperature, humidity, or vibrations).
The Influence of COD Fraction Forms and Molecules Size on Hydrolysis Process Developed by Comparative OUR Studies in Activated Sludge Modelling
- Jakub Drewnowski
- Bartosz Szeląg
- Li Xie
- Xi Lu
- Mahesh Ganesapillai
- Chinmoy Kanti Deb
- Joanna Szulżyk-Cieplak
- Grzegorz Łagód
2020 Full text MOLECULES
The activated sludge models (ASMs) commonly used by the International Water Association (IWA) task group are based on chemical oxygen demand (COD) fractionations. However, the proper evaluation of COD fractions, which is crucial for modelling and especially oxygen uptake rate (OUR) predictions, is still under debate. The biodegradation of particulate COD is initiated by the hydrolysis process, which is an integral part of an ASM. This concept has remained in use for over 30 years. The aim of this study was to verify an alternative, more complex, modified (Activated Sludge Model No 2d) ASM2d for modelling the OUR variations and novel procedure for the estimation of a particulate COD fraction through the implementation of the GPS-X software (Hydromantis Environmental Software Solutions, Inc., Hamilton, ON, Canada) in advanced computer simulations. In comparison to the original ASM2d, the modified model more accurately predicted the OUR behavior of real settled wastewater (SWW) samples and SWW after coagulation–flocculation (C–F). The mean absolute relative deviations (MARDs) in OUR were 11.3– 29.5% and 18.9–45.8% (original ASM2d) vs. 9.7–15.8% and 11.8–30.3% (modified ASM2d) for the SWW and the C–F samples, respectively. Moreover, the impact of the COD fraction forms and molecules size on the hydrolysis process rate was developed by integrated OUR batch tests in activated sludge modelling.
The influence of combination of binding agents on fatigue properties of deep cold in-place recycled mixtures in Indirect Tensile Fatigue Test (ITFT)
- Bohdan Dołżycki
- Cezary Szydłowski
- Mariusz Jaczewski
2020 Full text CONSTRUCTION AND BUILDING MATERIALS
The publication presents fatigue properties of cold recycled mixtures for eight combinations of binding agents (cement and bituminous emulsion). Cold recycled mixtures were evaluated in Indirect Tensile Fatigue Test (ITFT) at the temperature of 20 C in controlled stress mode. As a function of horizontal stress, fatigue life is strongly influenced by combination of the binding agents. When fatigue life is analyzed as a function of initial horizontal strain, the difference between different combinations decreases. In all cases, the influence of a specific binding agent is more visible for combinations with lower total amounts of the two agents.
The influence of polypropylene-block/graft-polycaprolactone copolymers on melt rheology, morphology, and dielectric properties of polypropylene/polycarbonate blends
- Anton Ginzburg
- Vaidyanath Ramakrishnan
- Luca Rongo
- Artur Rozanski
- Miloud Bouyahyi
- Lidia Jasinska-Walc
- Rob Duchateau
2020 RHEOLOGICA ACTA
The paper discusses the relationship between rheology and morphology of immiscible polypropylene (matrix))/polycarbonate (dispersed phase) blends compatibilized with novel polypropylene-polycaprolactone block and graft copolymers. Transmission electron microscopy (TEM) experiments revealed uniform droplet morphologies and a reduction of the average size of the dispersed phase upon addition of the compatibilizer. The results suggested the influence of the molecular weight distribution (MWD)/chemical composition distribution (CCD) and topology of the compatibilizer on the compatibilizing performance. Graft copolymers were found to be most effective in reducing the size of the dispersed phase, whereas the performance of block copolymers appeared to be highly dependent on the block length of PP. Small-amplitude oscillatory rheological experiments revealed an increase in elasticity at low frequencies caused by the interfacial interactions induced by the compatibilizer. The effect was quantified using the relaxation time spectrums that displayed the additional peak at longer relaxation times via Gramespacher-Meissner method. Broadband dielectric spectroscopy (BDS) revealed the influence of the copolymer architecture and molecular weight of the polypropylene blocks on the properties of the interfacial polarization, which was in line with both rheology and morphology data.
The Influence of Sulfate on Anaerobic Ammonium Oxidation in a Sequencing Batch Reactor
- Dominika Grubba
- Joanna Majtacz
2020 Full text Water
Anaerobic ammonia-oxidizing bacteria have a more comprehensive metabolism than expected - there may be other electron acceptors that oxidize ammonium nitrogen under anaerobic conditions, in addition to the well-known nitrite nitrogen, one of which is sulfate in the sulfammox process. Sulfate-containing compounds are part of the medium for the anammox process, but their concentrations are not particularly high (0.2 g MgSO4 ∙ 7H2O/dm3 and 0.00625 g FeSO4/dm3). They can react to some extent with influent ammonium nitrogen. In this work, tests were carried out in two sequencing batch reactors with granular sludge. The first reactor (R1) operated in a 6 hour cycle, and the concentration of the inflowing sulfate was kept at 44 mg/dm3∙d. The second reactor (R2) was operated until the 36th day in a 6 hour cycle; the influencing concentration was 180 mg SO42−/dm3∙d from the 37th to 64th day in a 3 hour cycle, with an influencing concentration of 360 mg SO42−/dm3∙d; and from the 65th to 90th day, the reactor was operated again in a 6 hour cycle with an influencing concentration of 180 mg SO42−/dm3∙d. Along with the increased share of sulfate, both the ammonium utilization rate and specific anammox activity showed an increasing trend. As soon as the sulfate dosage was reduced, the ammonium utilization rate and specific anammox activity values dropped. Therefore, it can be concluded that sulfate-containing compounds contribute to the efficiency and rate of the anammox process.
The Influence of the Aircraft Operating Fluids on the Mechanical Parameters of the Airport Surface Concrete
- Wojciech Żebrowski
- Paweł Wolka
- Marzena Kurpińska
2020 Full text Materials
The authors of the article assessed the impact of operating fluids used to service aircraft on changing mechanical parameters of cement concrete intended for airport pavement. The research concerned concrete designed with the use of CEM I 42.5N LH NA low-alkali cement, broken granite aggregate, fine washed aggregate, and admixtures. The analysis included the assessment of changes in dierences in endurance parameters over various research periods of up to 140 days. The obtained results allowed to carry out statistical analysis using the student’s T-test. Research has shown a significant impact of operational fluids used in aircraft on the surface concrete properties of the airport. A reduction in the compressive strength of concrete exposed to one of the tested operating liquid to a reduction of 7.2% was observed over a period of 140 days, while there was no significant impact of operating fluids on tensile strength at splitting.
The influence of the Cu2O deposition method on the structure, morphology and photoresponse of the ordered TiO2NTs/Cu2O heterojunction
- Zuzanna Molenda
- Katarzyna Grochowska
- Jakub Karczewski
- Jacek Ryl
- Kazimierz Darowicki
- Jakub Rysz
- Adam Cenian
- Katatrzyna SiuzdaK
2020 Materials Research Express
The increased interest in highly ordered titania structures exhibiting tubular shape that could be directly formed onto the stable substrate is related with the intensive research on their modification enabling absorption of light within the wide solar spectrum and its further conversion into electric or chemical energy. Among others, formation of uniform 3D heterojunctions based on the TiO2 nanotubes attracts attention since porous structure provides highly developed surface area whereas tubular shape ensures facilitated charge transport. Following that, we focus on the comparison of different electrochemical routes leading to the formation of Cu2O onto the titania nanotubes platform to improve energy harvesting. Proposed approach includes optimized potentiostatic and pulsed polarization of titania immersed in the basic electrolyte composed of Cu2+ ions stabilized by lactic acid. In this work, we demonstrate that at strictly selected deposition parameters, namely time, pulse width and cycle number, one can obtain titania nanotubes overgrown by Cu2O species uniformly distributed across the whole TiO2 layer as proved by secondary ion mass-spectrometry. X-ray photoelectron spectroscopy studies indicated purely Cu(I) oxide formation for pulsed deposition route. The photoactivity of obtained materials was verified both under vis and UV–vis irradiation. Depending on the incident light spectrum, variation in photoactivity was observed that is directly related with the charges generation and their transport within the junction. The transient photocurrent measurements show strong photocurrent enhancement for Cu2O modified titania comparing to pristine support and satisfactory photostability under visible light without any protective coating.
The Influence of the Cuboid Float’s Parameters on the Stability of a Floating Building
- Artur Karczewski
- Łukasz Piątek
2020 Full text Polish Maritime Research
Usually, the concept of sufficient stability of a floating structure is connected with the capacity to keep a small heel angle despite the moment of heeling. The variable responsible for these characteristics is the initial metacentric height, which is the relation between the hydrostatic features of the pontoon and the mass properties of the entire object. This article answers the questions of how heavy the floating system should be, what the minimum acceptable draft is, and whether it is beneficial to use internal fixed ballast. To cover various technologies, a theoretical model of a cuboid float with average density representing different construction materials was analysed. The results indicate that the common practice of using heavy and deep floating systems is not always reasonable. In the case of floating buildings, which, unlike ships, can be exploited only under small heel angles, the shape and width of the submerged part of the object may influence the stability more than the weight or draft.
The Influence of the Depth of Cut in Single-Pass Grinding on the Microstructure and Properties of the C45 Steel Surface Layer
- Marek Szkodo
- Karolina Chodnicka-Wszelak
- Mariusz Deja
- Alicja Stanisławska
- Michał Bartmański
2020 Full text Materials
The paper contains the results of a metallographic examination and nanoindentation test conducted for the medium carbon structural steel with low content of Mn, Si, Cu, Cr, and Ni after its grinding to a depth ranging from 2 μm to 20 μm, at constant cutting speed (peripheral speed) of vs = 25 ms−1 and constant feed rate of vft = 1 m/min. Applied grinding parameters did not cause the surface layer hardening, which could generate an unfavorable stress distribution. The increase in the surface hardness was obtained due to the work hardening effect. Microstructure, phase composition, and chemical composition of the grinded surface layer were examined using an X‐ray diffractometer, light microscope, and scanning microscope equipped with X‐ray energy‐dispersive spectroscopy, respectively. Hardness on the grinded surface and on the cross‐section was also determined. It was shown that the grinding of C45 steel causes work hardening of its surface layer without phase transformation. What is more, only grinding to a depth of 20 μm caused the formation of an oxide scale on the work‐hardened surface layer. Nanoindentation test on the cross‐ section, at a short distance from the grinded surface, has shown that ferrite grains were more susceptible to work hardening than pearlite grains due to the creation of an equiaxed cellular microstructure, and that different dislocation substructure was created in the work‐hardened surface layer after grinding to different depths.
The Influence of the Electrodeposition Parameters on the Properties of Mn-Co-Based Nanofilms as Anode Materials for Alkaline Electrolysers
- Karolina Cysewska
- Maria Rybarczyk
- Grzegorz Cempura
- Jakub Karczewski
- Marcin Łapiński
- Piotr Jasiński
- Sebastian Molin
2020 Full text Materials
In this work, the influence of the synthesis conditions on the structure, morphology, and electrocatalytic performance for the oxygen evolution reaction (OER) of Mn-Co-based films is studied. For this purpose, Mn-Co nanofilm is electrochemically synthesised in a one-step process on nickel foam in the presence of metal nitrates without any additives. The possible mechanism of the synthesis is proposed. The morphology and structure of the catalysts are studied by various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The analyses show that the as-deposited catalysts consist mainly of oxides/hydroxides and/or (oxy)hydroxides based on Mn2+, Co2+, and Co3+. The alkaline post-treatment of the film results in the formation of Mn-Co (oxy)hydroxides and crystalline Co(OH)2 with a β-phase hexagonal platelet-like shape structure, indicating a layered double hydroxide structure, desirable for the OER. Electrochemical studies show that the catalytic performance of Mn-Co was dependent on the concentration of Mn versus Co in the synthesis solution and on the deposition charge. The optimised Mn-Co/Ni foam is characterised by a specific surface area of 10.5 m2·g−1, a pore volume of 0.0042 cm3·g−1, and high electrochemical stability with an overpotential deviation around 330–340 mV at 10 mA·cm−2geo for 70 h.
The influence of thermal treatment on electrocatalytic properties of Mn-Co nanofilms on nickel foam toward oxygen evolution reaction activity
- Karolina Cysewska
- Grzegorz Cempura
- Jakub Karczewski
- Marcin Łapiński
- Piotr Jasiński
- Sebastian Molin
2020 MATERIALS LETTERS
This work evaluates electrodeposited and differently treated Mn-Co catalysts for their oxygen evolution reaction activity. Catalysts are evaluated in the as-deposited and heat treated state: after 350 C and 600 C. Results show that the highest electrochemical activity is obtained for the as-deposited Mn-Co oxyhydroxide, which possibly possess a layered double hydroxide structure. After the heat treatment process, especially after 600 C, the electrochemical performance decreases considerably.
The Influence of Water and Mineral Oil on Mechanical Losses in a Hydraulic Motor for Offshore and Marine Applications
- Paweł Śliwiński
2020 Full text Polish Maritime Research
In this paper, mechanical losses in a hydraulic motor supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were onducted using a special design (prototype) of a hydraulic satellite motor. The design of the satellite motor is presented. This motor was developed to supply both with water and mineral oil and features a non-circular tooth working mechanism. The paper also characterizes sources of mechanical losses in this motor. On this basis, a mathematical model of these losses has been developed nd presented. The results of calculation of mechanical losses according to the model are compared with the experimental results. Experimental studies have shown that the mechanical losses in the motor supplied with water are 2.8 times greater than those in the motor supplied with oil. The work demonstrates that the mechanical losses in both the motor supplied with water and the one supplied with oil are described well by the mathematical model. It has been found that for the loaded motor working at high speed, the simulation results differ from experimental ones by no more than 3% for oil and 4% for water.
The influence of welding heat input on the quality and properties of high strength low-alloy dissimilar steel butt joints
- Jacek Tomków
- Jacek Haras
2020 Full text Przegląd Spawalnictwa
The paper presents the results of non-destructive and destructive tests of dissimilar highstrength low-alloy S460ML and S460N steel butt joints. These steels are characterized by similar mechanical properties, but their carbon equivalent CeIIW values are much different. The joints were made using different values of heat input for each welding bead. They were tested by non-destructive methods: visual, penetrant, radiographic and ultrasonic tests. Then, the destructive tests were made: static tensile test, bending test, impact test and Vickers HV10 hardness measurements. The results of prepared examinations showed, that welding with higher heat input has significant impact on the mechanical properties of the dissimilar steel joints the joint welded with bigger heat input was characterized by better mechanical properties.
The Influent Effects of Flow Rate Profile on thePerformance of Microbial Fuel Cells Model
- Szymon Potrykus
- Sara Mateo
- Janusz Nieznański
- Francesco Jesus Fernández-Morales
2020 Full text ENERGIES
The energy contained in wastewaters has been identified as a promising sustainableenergy resource that could be harvested by using microbial fuel cells (MFC). When dealing with realwastewaters, the MFCs should be able to manage high flow rates and flow rates fluctuations. In thiswork, the short-term effects of the influent flow rate variations on the performance of a microbialfuel cell has been studied. With this aim, the influent flow rate was stepwise increased from 0.72 to7.2 L/d and then stepwise decreased. The obtained results indicate that, on the one hand, an increasein the influent flow rate leads to higher chemical oxygen demand removal rates up to 396 g/(L/d) andhigher electric power generation almost 18 mW/m2, but to lower coulombic efficiencies. On the otherhand, the reduction of the flow rate increases the coulombic efficiencies, as well as the percentageof chemical oxygen demand removed, but decreases electric power generation. In the short-term,the exposition to higher influent flow rates causes the growth of the microbial population of the MFC,the growth of the non-electrogenic microorganisms being higher than that of the electrogenic ones.The higher growth of non-electrogenic microorganisms may lead to lower coulombic efficiencies.
The interaction parameters for solutions of n-butylurea in aqueous solutions of N-methylacetamide – The volumetric and compressibility studies between 288.15 K and 308.15 K
- Emilia Kaczkowska
- Jarosław Wawer
- Magdalena Tyczyńska
- Małgorzata Jóźwiak
- Joanna Krakowiak
2020 JOURNAL OF CHEMICAL THERMODYNAMICS
Densities and speed of sound were measured for solutions of n-butylurea in aqueous solution of Nmethylacetamide 2, 4, 6 and 8 (mol/kg) at T = (288.15, 298.15 and 308.15) K. From these data the apparent molar volumes, Vf, the apparent molar isentropic compressions, KSf, of the solute were determined. The concentration dependencies of the calculated quantities have been used to obtain the standard partial molar parameters. The latter values were combined with the previously published volumetric and compressibility data for n-butylurea in pure water to obtain the partial molar properties of transfer from water to aqueous N-methylacetamide solutions. These parameters were used to determine the interaction parameters according to the McMillan-Mayer theory. The calculated parameters and their temperature characteristics are discussed in terms of solute–solvent, solute–solute and solute–cosolute interactions.
The managerial role in organizational culture as perceived by management students
- Marta Szeluga-Romańska
- Anna Modzelewska
2020 Full text Journal of Entrepreneurship, Management and Innovation
This paper aims at illustrating the multidimensional role of the manager and its mutual influence on organizational culture from amanagement students’ perspective. The main part of the text was based on own qualitative research – interviews, a questionnaire, and a narrative collage – which was conducted over a 10 year period among management students. Ninety-seven students from the Jagiellonian University and the Gdańsk University of Technology took part in the research. In order to gather, analyze and interpret the data, and to achieve reliable results, we followed the thematic analysis rules. We investigated the empirical material, provided by the management students responses to the research questions posed in the questionnaire, in the search for interesting threads, seeking a definition and an understanding of the term “manager” and the specifics of a manager’s work. We also presented several quotes from the data in accordance with the principles of data analysis in qualitative research methodology. Four different prisms were identified: gender, relational, constant learning and professional, described as the areas of managerial duties, features, and expectations. The article’s key value is the focus on students’ perception – an idealized construct of the managerial role, which states a benchmark for their own actual and prospect managerial performance. Such a perspective is very important for practice as well as for education. From a practical point of view, some management students will manage teams or organizations in the future. They should be aware of managerial duties’ elaborate character and the multiple demands on the role’s performance. They will shape the role by themselves. On the other hand, from an educational point of view, it is essential to give students some insight into their prospective role, understand the elaborate organizational relations, and the activities that appear in organizational culture that always influence management.
The mechanical properties and bactericidal degradation effectiveness of tannic acid-based thin films for wound care
- B. Kaczmarek
- Marcin Wekwejt
- K. Nadolna
- A. Owczarek
- O. Mazur
- Anna Pałubicka
2020 Full text Journal of the Mechanical Behavior of Biomedical Materials
The surface area is the most important aspect when considering the interactions between a material and the surrounding environment. Chitosan (CTS) and tannic acid (TA) were previously successfully tested by us to obtain thin films to serve as wound dressings or food packaging materials. However, surface properties as well as the antimicrobial activity of the material were not considered. They are important if the material is likely to find application in biomedical or food packaging application. Thereby, this study is a further investigation of chitosan/tannic acid films surface properties. The results showed that higher content of tannic acid increases the surface free energy and roughness, which is beneficial when considering the application of the materials as wound dressings. However, higher content of chitosan provides better antibacterial properties. Hence, the most optimal complex of chitosan and tannic acid for proposed application is the ratio 80/20.