2018 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2018

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TIME SERIES DATA FOR 3D FLOOD MAPPING
- Beata Wieczorek
- Anna Sobieraj-Żłobińska
- Tomasz Sidorowicz
2018
Thanks to the ability to collect information about large areas and with high frequency in time areas threatened by floods can be closely monitored. The effects of flooding are socio-economic losses. In order to reduce those losses, actions related to the determination of building zones are taken. Moreover, the conditions to be met by facilities approved for implementation in such areas are determined. Therefore, satellite data from the Earth observation program play a key role in assessing water conditions that are variable in space and in time. The article specifies the probability of flooding the area in the vicinity of the Łyna River valley in the Sępopol commune. The analysis has been carried out for areas where floods have occurred. The spatial data from airborne laser scanning and satellite radar interferometry was examined in the context of its usefulness in the determination of the maximum possible extent of flooding. In order to transform data into useful information, it was necessary to integrate both the spatial and temporal dimension of the SAR time series. Finally, digital terrain model with high resolution was created.
Time-domain measurement methods for R, L and C sensors based on aversatile direct sensor-to-microcontroller interface circuit
- Zbigniew Czaja
2018 Full text SENSORS AND ACTUATORS A-PHYSICAL
tIn the paper new time-domain measurement methods for determining values of resistive (R), inductive(L) and capacitive (C) sensors based on a versatile direct sensor-to-microcontroller interface for microcon-trollers with internal analog-to-digital converters (ADCs) and analog comparators (ACs) are presented.The interface circuit consists of a reference resistor Rrworking as a voltage divider, a given R, L or C sensorand a microcontroller (its peripherals: an ADC, an AC, a timer, I/O pins buffered by an inverter). A pro-totype of the proposed complete solution of a compact smart sensor based on an 8-bit microcontrollerhas been developed and tested. The maximum possible relative inaccuracy of an indirectly measurableresistance, inductance and capacitance were analysed. Also, experimental researches were made. Thefollowing relative errors of the sensor value determination were achieved: for the R sensor less than 3%,as well as very good results for the L sensor (less than 0.3%) and for the C sensor (less than 0.2%).
Time-of-flight electron scattering from molecular hydrogen: Benchmark cross sections for excitation of the X1Σ+g→b3Σ+u transition
- Mateusz Zawadzki
- Robert Wright
- Grant Dolmat
- Merl Martin
- Leigh Hargreaves
- Dmitry Fursa
- Mark Zammit
- Liam Scarlett
- Jonathan Tapley
- Jeremy Savage
- Igor Bray
- Murtadha Khakoo
2018 Full text PHYSICAL REVIEW A
The electron impact X1Σ+g to b3Σ+u transition in molecular hydrogen is one of the most important dissociation pathways to forming atomic hydrogen atoms, and is of great importance in modeling astrophysical and industrial plasmas where molecular hydrogen is a substantial constituent. Recently it has been found that the convergent close-coupling (CCC) cross sections of Zammit et al. [Phys. Rev. A 95, 022708 (2017)] are up to a factor of two smaller than the currently recommended data. We have performed measurements of differential cross sections as ratios of the excitation to elastic scattering using a transmission-free time-of-flight electron spectrometer, and find excellent agreement with the CCC calculations. Since there is already excellent agreement for the absolute elastic differential cross sections, we establish new recommended differential and integrated cross sections with theory and experiment being essentially in complete agreement- unprecedented for differential electron impact excitation of any molecular transition to date.
TiO 2 Co x O y composite nanotube arrays via one step electrochemical anodization for visible light–induced photocatalytic reaction
- Marek Kobylański
- Paweł Mazierski
- Anna Malankowska
- Magda Kozak
- Magdalena Diak
- Michał Jerzy Winiarski
- Tomasz Klimczuk
- Wojciech Lisowski
- Grzegorz Nowaczyk
- Adriana Zaleska-Medynska
2018 Surfaces and Interfaces
TiO2CoxOy (x = 1, y = 1 or x = 3, y = 4) composite photocatalysts have been synthesized via one step anodic anodization of TiCo alloys. The effects of the cobalt content in the alloy (5, 10 and 15 wt%), water content (2, 5 and 10%) in the electrolyte solution, and applied voltage (30, 40 and 50 V) during the anodization process on the morphology and surface properties. Additionally, the dependence of cobalt content in the nanotubes (0.06–0.09 at. %) on photocatalytic properties of the obtained materials have been investigated systematically. It was shown that the amount of cobalt in the TiCo alloy affected morphology as well as photocatalytic activity of obtained composites. Moreover, the diameter and wall thickness of the TiO2CoxOy composites could be precisely controlled by applied voltage value, water content in electrolyte and cobalt content in the working electrode. The TiO2CoxOy composite nanotubes exhibit enhanced photocatalytic degradation rate of 0.444 µmol·dm−3·min−1 for phenol under visible light compared with unmodified TiO2 NTs 0.140 µmol·dm−3·min−1. XPS analysis revealed that the content of Co species in the surface layer of nanotubes is similar (from 0.06 to 0.09 at.%), independently on cobalt amount in used substrate, due to leakage of Co ions to the electrolyte during anodic oxidation. Phenol degradation in the presence of scavengers shown that the superoxide radical species O2•− were found to be main active species responsible for high efficiency of degradation.
TIRE/ROAD NOISE AND TIRE ROLLING RESISTANCE ON PROTOTYPE PERS SURFACE
- Stanisław Taryma
- Ryszard Woźniak
- Jerzy Ejsmont
- Piotr Mioduszewski
- Grzegorz Ronowski
2018 Full text IOP Conference Series: Materials Science and Engineering
Poroelastic road surfaces are characterized by low noise of tires running on them.Road pavements of this type are promising solution to problems related to traffic noise in cities and on rural roads. Some technical problems still have to be solved, in particular regarding durability and skid resistance on wet surface. Ongoing and planned works are to contribute to create a quiet, durable and safe road surface, which will become an alternative to acoustic screens and vehicle speed reduction as an efficient noise reduction measure. The paper presents the results of laboratory and road tests of tire/road noise and rolling resistance on the prototype poroelastic surface (PERS) compared to the surfaces selected as a reference.
Tire/Road Noise On Poroelastic Road Surfaces - Results Of Laboratory Measurements
- Jerzy Ejsmont
- Beata Świeczko-Żurek
- Wojciech Owczarzak
- Sławomir Sommer
- Grzegorz Ronowski
2018 Full text
Tire/road noise is the most important part of traffic noise for medium and high speed driving both in the case of passenger cars and trucks. The potential to make modification of tires that significantly reduce tire/road noise in nearly over, at least for conventional tires so the only promising action is to improve road pavements. One of the innovative solutions is poroelastic road pavement (PERS) that reduces airflow related noise mechanisms due to its porosity and impact related mechanisms owing to its elasticity. Although the existing PERS test sections are still struggling with certain problems most notably non satisfactory durability and somewhat low friction, the experiments show that substantial progress is possible and the acoustic performance of PERS is very good making it the most quiet road pavements so far. The paper presents results of laboratory tests of PERS performed at the Technical University of Gdańsk both for car and truck tires.
Titania nanotubes modified by a pyrolyzed metal-organic framework with zero valent iron centers as a photoanode with enhanced photoelectrochemical, photocatalytical activity and high capacitance
- Mariusz Szkoda
- Konrad Trzciński
- Andrzej Nowak
- Emerson Coy
- Leszek Wicikowski
- Marcin Stanisław Łapiński
- Katarzyna Siuzdak
- Anna Lisowska-Oleksiak
2018 ELECTROCHIMICA ACTA
The paper discusses the synthesis, photoelectrochemical and electrochemical behaviour of titania nanotube arrays modified by a pyrolyzed metal-organic framework (MOF). A poly(3,4–ethylenedioxyphene) (PEDOT) matrix with an embedded inorganic network of iron hexacyanoferrate (BP) covering TiO2 nanotubes (TNT) is used as a MOF for the further sintering procedure, resulting in a novel, thin film of carbonaceous wrap supported Fe catalytic centers: TNT@C:Fe. UV–Vis and Raman spectroscopies were utilized to characterize the absorbance capability and the crystalline phase of titania, respectively. XPS was used for identification of the valence stage of iron Fe(0), Fe(II), Fe(III) in the shell part of the novel composite TNT@C:Fe. The electrochemical performance of the modified nanotubular TiO2 electrodes has been monitored by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge cycles in an aqueous electrolyte. TNT@C:Fe exhibited the capacitance of 9.1 mF cm−2 even after 5000 cycles, being much higher than pure titania (2.1 mF cm−2). The photocurrent density reached 304 μA cm−2 for TNT@C:Fe, whereas only 32 μAcm−2 was registered for pure titania nanotubes under simulated solar light illumination at a potential of +0.5 V. An improved decolorization rate of methylene blue in water confirms enhanced photoactivity of TNT@C:Fe in comparison with pristine titania nanotubes.
Tłumienie drgań w elektromechanicznych strukturach periodycznych
- Wiktor Waszkowiak
2018 Full text
Praca dotyczy wykorzystania elektromechanicznych struktur periodycznych do tłumienia drgań jedno- i dwuwymiarowych elementów konstrukcyjnych. Głównym celem pracy było opracowanie modeli numerycznych jedno- i dwuwymiarowych struktur periodycznych, zarówno pasywnych jak i aktywnych oraz jednowymiarowych wykorzystujących elementy piezoelektryczne. Cel ten osiągnięto dzięki przeprowadzeniu symulacji komputerowych w oparciu o opracowane modele numeryczne na bazie metody spektralnych elementów skończonych w dziedzinie czasu i częstotliwości. Uzyskane wyniki symulacji zostały zweryfikowane eksperymentalnie dzięki wykorzystaniu laserowej wibrometrii skaningowej. W odniesieniu do jedno- i dwuwymiarowych pasywnych struktur periodycznych analizie poddano drgania własne: wzdłużne, giętne i skrętne belek izotropowych oraz tarcz i płyt. Zbadano również efektywność tłumienia fal sprężystych w jedno- i dwuwymiarowych strukturach periodycznych. W odniesieniu do jednowymiarowych struktur aktywnych, wykorzystujących elementy piezoelektryczne pracujące w układzie rezonansowym RLC, analizie poddano drgania wymuszone wzdłużne i giętne oraz badano propagacje fal wzdłużnych i giętnych. Sprawdzono również wpływ parametrów układu rezonansowego RLC na drgania i fale propagowane w strukturach. Uzyskane wyniki badań pozwoliły na określenie ogólnych zależności występowania zjawisk wynikających z periodyczności struktury, manifestujących się obecnością pasm zabronionych, od parametrów struktury periodycznej, czy to pasywnej czy aktywnej, i jej komórki elementarnej. Pokazano, że struktury periodyczne z aktywnymi elementami piezoelektrycznymi włączonymi w obwód rezonansowy RLC mogą być z powodzeniem wykorzystywane do tłumienia drgań w sposób kontrolowany.
Tome-lapse X-ray tomography imaging of flow patterns in versatile silo model
- Laurent Babout
- Krzysztof Grudzień
- Selam Waktola
- Maciej Niedostatkiewicz
- Adrien Jerome
- Maire Eric
2018
The paper introduces a new versatile silo model that was especially designed for in situ X-ray tomography studies of silo discharge for various flow conditions, namely concentric and eccentric. The presented work focuses on organic granular materials where low fraction of short-grain white rice is mixed with spheroidal sorghum particles. The high-quality tomography images combined with adequate image processing strategy allows to unambiguously analyze individual grains dynamic behavior during silo discharge. The quantitative image analysis also reveals granular compaction rates in different zones of the funnel flow, which are in agreement with the literature. The proposed experimental methodology is proven to be solid enough to investigate in more details dynamic phenomena during silo discharge. It can also serve as a strong baseline for numerical calibration and predications.
Topological modifications for performance improvement and size reduction of wideband antenna structures
- Adrian Bekasiewicz
- Sławomir Kozieł
2018 Full text
Compact antennas belong to the key components of modern communication systems. Their miniaturization is often achieved by introducing appropriate topological changes such as simple ground plane slots or tapered feeds. More sophisticated modifications are rarely considered in the literature because they normally lead to significant increase of the number of tunable parameters, which makes the antenna design process more challenging. On the other hand, complex topological changes are questionable as their effects on radiator performance and/or size reduction are difficult to be verified in practice. In particular, parameter sweeping commonly used for dimension adjustment is incapable of their appropriate handling. In this work, the effect of feed line and ground plane modifications on performance and size reduction of a wideband antenna is investigated. Considered geometrical changes include a ground plane slot and a stepped impedance feed line (both with gradually increasing number of sections). The modified structures have been optimized for minimum in-band reflection and minimum size using a robust gradient-based algorithm. The obtained results demonstrate that complex topological modifications may be useful for achieving both good performance and small size when handled comprehensively.
Torsional buckling and post-buckling of columns made of aluminium alloy
- Czesław Szymczak
- Marcin Kujawa
2018 Full text APPLIED MATHEMATICAL MODELLING
The paper concerns torsional buckling and the initial post-buckling of axially compressed thin-walled aluminium alloy columns with bisymmetrical cross-section. It is assumed that the column material behaviour is described by the Ramberg–Osgood constitutive equation in non-linear elastic range. The stationary total energy principle is used to derive the governing non-linear differential equation. An approximate solution of the equation determined by means of the perturbation approach allows to determine the buckling loads and the initial post-buckling behaviour. Numerical examples dealing with simply supported I-column are presented and the effect of material elastic non-linearity on the critical loads and initial post-buckling behaviour are compared to the linear solution.
Total domination in versus paired-domination in regular graphs
- Joanna Cyman
- Magda Dettlaff
- Michael A. Henning
- Magdalena Lemańska
- Joanna Raczek
2018 Full text Discussiones Mathematicae Graph Theory
A subset S of vertices of a graph G is a dominating set of G if every vertex not in S has a neighbor in S, while S is a total dominating set of G if every vertex has a neighbor in S. If S is a dominating set with the additional property that the subgraph induced by S contains a perfect matching, then S is a paired-dominating set. The domination number, denoted γ(G), is the minimum cardinality of a dominating set of G, while the minimum cardinalities of a total dominating set and paired-dominating set are the total domination number, \gt(G), and the paired-domination number, \gp(G), respectively. For k ≥ 2, let G be a connected k-regular graph. It is known [Schaudt, Total domination versus paired domination, Discuss. Math. Graph Theory 32 (2012) 435--447] that \gpr(G)/γt(G) \le (2 k)/(k + 1). In the special case when k = 2, we observe that \gpr(G)/γt(G) \le 4/3, with equality if and only if G \cong C5. When k = 3, we show that \gpr(G)/γt(G) \le 3/2, with equality if and only if G is the Petersen graph. More generally for k ≥ 2, if G has girth at least 5 and satisfies \gpr(G)/γt(G) = (2 k)/(k + 1), then we show that G is a diameter-2 Moore graph. As a consequence of this result, we prove that for k ≥ 2 and k \ne 57, if G has girth at least 5, then \gpr(G)/γt(G) \le (2 k)/(k + 1), with equality if and only if k=2 and G \cong C5 or k = 3 and G is the Petersen graph.
Total Domination Versus Domination in Cubic Graphs
- Joanna Cyman
- Magda Dettlaff
- Michael A. Henning
- Magdalena Lemańska
- Joanna Raczek
2018 Full text GRAPHS AND COMBINATORICS
A dominating set in a graph G is a set S of vertices of G such that every vertex not in S has a neighbor in S. Further, if every vertex of G has a neighbor in S, then S is a total dominating set of G. The domination number,γ(G), and total domination number, γ_t(G), are the minimum cardinalities of a dominating set and total dominating set, respectively, in G. The upper domination number, \Gamma(G), and the upper total domination number, \Gamma_t(G), are the maximum cardinalities of a minimal dominating set and total dominating set, respectively, in G. It is known that γ_t(G)/γ (G)≤2 and \Gamma_t(G)/ \Gamma(G)≤2 for all graphs G with no isolated vertex. In this paper we characterize the connected cubic graphs G satisfying γ_t(G)/γ (G)=2, and we characterize the connected cubic graphs G satisfying \Gamma_t(G)/ \Gamma(G)=2.
Toughness augmentation by fibrillation and yielding in nanostructured blends with recycled polyurethane as a modifier
- Arunima Reghunadhan
- Janusz Datta
- Nandakumar Kalarikkal
- Józef Haponiuk
- Sabu Thomas
2018 APPLIED SURFACE SCIENCE
In the present paper, we have carefully investigated the morphology and fracture mechanism of the recycled polyurethane (RPU) /epoxy blend system. The second phase (RPU) added to the epoxy resin has a positive effect on the overall mechanical properties. Interestingly, the recycled polymer has a remarkable effect on the fracture toughness of epoxy resin. The mechanism behind the fracture toughness improvement up on the addition of RPU was found to be very similar to that of the incorporation of hyperbranched polymers in epoxy resin. Brittle to ductile fracture was clear in the case of higher loadings such as 20 and 40 phr of RPU in the epoxy resin. The mechanism behind improvement of fracture toughness was found to fibrillation of the RPU phase which was evidenced by the fracture morphology. In fact the force applied to the epoxy matrix was effectively transferred to the added RPU phase due to its strong interaction with the epoxy phase. This effective transfer of force to the RPU phase protects the epoxy matrix without catastrophic failure and we observed 44% increase in G1C values at an addition of 40 phr RPU. This results in the extensive fibrillation of RPU which causes the generation of new surfaces. Thus the impact energy has been fully utilized by the RPU phase. The mechanism is termed as simultaneous reinforcing and toughening and normally reported as a result of cavitations and yielding. SEM, HRTEM and AFM analyses clearly demonstrated the fibrillated morphology of the fracture surface and the formation of nanostructures. This report is first of its kind in the case of both epoxy modification and the elastomer toughening.
Toward Intelligent Vehicle Intrusion Detection Using the Neural Knowledge DNA
- Fei Li
- Haoxi Zhang
- Juan Wang
- Cesar Sanin
- Edward Szczerbicki
2018 Full text CYBERNETICS AND SYSTEMS
In this paper, we propose a novel intrusion detection approach using past driving experience and the neural knowledge DNA for in-vehicle information system security. The neural knowledge DNA is a novel knowledge representation method designed to support discovering, storing, reusing, improving, and sharing knowledge among machines and computing systems. We examine our approach for classifying malicious vehicle control commands based on learning from past valid driving behavior data on a simulator.
Towards a method for detecting large roll motions suitable for oceangoing ships
- Maria Acanfora
- Przemysław Krata
- Jakub Montewka
- Pentti Kujala
2018 APPLIED OCEAN RESEARCH
The concept of autonomous merchant ships is quite recent. The increasing interest in autonomous vessels is nowadays calling for smart technologies that are supposed to replace the human actions on board. This involves troublesome issues related to ship safety. In the future, decision-making processes that are conventionally performed by human beings on board ship will be moved ashore to the control centre and maybe even completely replaced by computers and smart technologies. This paper proposes a method suitable for oceangoing ships, providing an autonomous routine for the avoidance of two dangerous phenomena involving excessive motions of the ship, e.g. the synchronous roll and the parametric resonance, both taking place in rough seas. The method is two-fold, since it pertains to the process of route planning and route monitoring and it encompasses two submethods (A and B). Submethod A is used to define a set of operational scenarios to be avoided due to excessive accelerations, with the use of a numerical ship motion model. This is applied at the route-planning stage. Submethod B is developed to monitor ship motions and to detect large roll motion for a ship in the seaway. It also raises alerts at two levels, first when the large roll motions are expected to develop (leaving ample time for remotely located operators to react), second when the large roll motions are developing (leaving a short time window for action taken on board the ship). The main sources of uncertainty are defined and the solutions to address those are proposed. Finally, the method is applied on simulated time histories of ship motion, which is a container ship traversing the Pacific Ocean. The obtained results are promising; however, further work is required with respect to various manoeuvers performed by a ship in the seaway.
Towards Audio Signal Equalization Based on Spectral Characteristics of a Listening Room and Music Content Reproduced
- Piotr Hoffmann
- Bożena Kostek
2018
This study presents investigations of the influence of the room acoustics on the frequency characteristic of the audio signal playback. First, the concept of a novel spectral equalization method of the room acoustic conditions is introduced. On the basis of the room spectral response, a system for room acoustics compensation based on an equalizer designed is proposed. The system settings depend on music genre recognized automatically. In order to acquire room acoustic characteristics, a series of measurements are performed. The impact of the enclosure on particular music genre spectral characteristics has also been presented. In the analyses a comparison of spectral characteristics obtained with pink noise and music genres as measurement signals is presented.
Towards Contactless, Hand Gestures-Based Control of Devices
- Krzysztof Czuszyński
- Jacek Rumiński
2018
Gesture-based intuitive interactions with electronic devices can be an important part of smart home systems. In this paper, we adapt the contactless linear gesture sensor for the navigation of smart lighting system. Set of handled gestures allow to propose two methods of active light source selection, continuous dimming, and turning on and off based on discrete gestures. The average gesture recognition accuracy was 97.58% in the first of proposed methods of lamp selection and 95.45% in the second method. Apart of the accuracy of the gesture sensor in the real case implementation the user convenience of navigation was monitored. 72.73% of users pointed the first method as more intuitive and convenient to use. 63.64% of users indicated that the dimming of light is more intuitive when moving a hand along the sensor than closing it towards the package. The impact of utilizing dirty or gloved hand on the pose recognition accuracy of the sensor was verified as well. The results indicate the capability of incorporating considered touchless gesture sensor to homes, factories or operating rooms. These are places where the need of the functionality of discrete and continuous gestures for handling some basic devices or functions can be limited due to dirty hand scenarios or sterility requirements.
Towards high quality ITO coatings: the impact of nitrogen admixture in HiPIMS discharges
- Vitezslav Stranak
- Robert Bogdanowicz
- Petr Sezemsky
- Harm Wulff
- Angela Kruth
- Mateusz Smietana
- Jiri Kratochvil
- Martin Cada
- Zdenek Hubicka
2018 SURFACE & COATINGS TECHNOLOGY
The paper reports controlled deposition of optically transparent and electrically conductive ITO films prepared by a combination of rf (13.56 MHz) and High Power Impulse Magnetron Sputtering (HiPIMS) systems without any post deposition thermal treatment/annealing. It is shown that (i) reactive admixture of N2 gas to the process and (ii) pressure in the deposition chamber enable to optimize optical properties of ITO films. Furthermore, the changes of electrical resistivity were observed, too. The variation of these ITO properties are attributed to change of crystalline structure measured by XRD methods.
Towards New Mappings between Emotion Representation Models
- Agnieszka Landowska
2018 Full text Applied Sciences-Basel
There are several models for representing emotions in affect-aware applications, and available emotion recognition solutions provide results using diverse emotion models. As multimodal fusion is beneficial in terms of both accuracy and reliability of emotion recognition, one of the challenges is mapping between the models of affect representation. This paper addresses this issue by: proposing a procedure to elaborate new mappings, recommending a set of metrics for evaluation of the mapping accuracy, and delivering new mapping matrices for estimating the dimensions of a Pleasure-Arousal-Dominance model from Ekman’s six basic emotions. The results are based on an analysis using three datasets that were constructed based on affect-annotated lexicons. The new mappings were obtained with linear regression learning methods. The proposed mappings showed better results on the datasets in comparison with the state-of-the-art matrix. The procedure, as well as the proposed metrics, might be used, not only in evaluation of the mappings between representation models, but also in comparison of emotion recognition and annotation results. Moreover, the datasets are published along with the paper and new mappings might be created and evaluated using the proposed methods. The study results might be interesting for both researchers and developers, who aim to extend their software solutions with affect recognition techniques.