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Gdańsk University of Technology

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Publications from the year 2019

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  • Intelligent Autonomous Vehicles
    • Bogdan Wiszniewski
    • Zdzisław Kowalczuk
    • Mariusz Domżalski
    2019

    Advanced mobile vehicles and robots have long been one of the main issues in engineering. They have various applications in emergency, lifeguarding and entertainment as well as in various industrial, civil and military systems. Among them, you can distinguish robots that can move in an open environment or operate only in predetermined confined spaces. Open world robots are very demanding because they have to map their environment, adapt to changes and make their own decisions. In addition, current trends in robotics point to different social aspects and the importance of robot friendliness for humans.

  • Intelligent monitoring the vertical dynamics of wheeled inspection vehicles
    • Janusz Kozłowski
    • Zdzisław Kowalczuk
    2019 Full text IFAC-PapersOnLine

    The problem of intelligent monitoring of the vertical dynamics of wheeled inspection vehicles is addressed. With the independent MacPherson suspension system installed, the basic analysis focuses on the evaluation of the parameters of the so-called quarter car model. To identify a physically motivated continuous description, in practice, dedicated integral-horizontal filters are used. The obtained discrete model, which retains the original parameters, is effectively identified using the classic least squares procedure. Using the method of identification in the sense of the least sum of absolute values, the results of such an assessment become insensitive to sporadic outliers in the sampled data. However, the early signs of possible mechanical defects of the suspension can be seen using the forgetting mechanism. This helps to identify failures that can be recognized by changes in system parameters. Ultimately, the quality of the intelligent vehicle suspension monitoring developed is verified by means of numerical simulations. The problem of intelligent monitoring of the vertical dynamics of wheeled inspection vehicles is addressed. With the independent MacPherson suspension system installed, the basic analysis focuses on the evaluation of the parameters of the so-called quarter car model. To identify a physically motivated continuous description, in practice, dedicated integral-horizontal filters are used. The obtained discrete model, which retains the original parameters, is effectively identified using the classic least squares procedure. Using the method of identification in the sense of the least sum of absolute values, the results of such an assessment become insensitive to sporadic outliers in the sampled data. However, the early signs of possible mechanical defects of the suspension can be seen using the forgetting mechanism. This helps to identify failures that can be recognized by changes in system parameters. Ultimately, the quality of the intelligent vehicle suspension monitoring developed is verified by means of numerical simulations

  • Interactions of N-alkyl-N-methylmorpholinium based ionic liquids with acetonitrile studied by density and velocity of sound measurements and molecular dynamics simulations
    • Łukasz Marcinkowski
    • Maciej Śmiechowski
    • Emil Szepiński
    • Adam Kloskowski
    • Dorota Warmińska
    2019 JOURNAL OF MOLECULAR LIQUIDS

    Morpholinium-based ionic liquids (ILs) and their mixtures with polar co-solvents are an interesting class of emerging electrolytes in electrochemistry that is relatively poorly studied. In this work, densities and sound velocities of four ILs, N-ethyl-N-methylmorpholinium tetrafluoroborate, N-butyl-N-methylmorpholinium tetrafluoroborate, N-octyl-N-methylmorpho-linium tetrafluoroborate and N-decyl-N-methylmorpholinium tetrafluoroborate were measured in acetonitrile (AN) at T = (298.15–328.15) K and at atmospheric pressure. These data were used to calculate the apparent molar volumes and the apparent molar compressibilities as a function of molality. Then, an extrapolation procedure based on Masson and Redlich–Meyer equations were applied to evaluate the values of the limiting apparent molar volume and the limiting apparent molar compressibility. The limiting apparent molar expansibility coefficients were obtained from the slopes of the apparent molar volume at infinite dilution versus temperature. Using molecular dynamics simulations the degree of association of ILs in AN was calculated. Moreover, limiting apparent molar volumes were estimated and compared with the experimental values. The results indicate that the most significant factor controlling the volumetric and acoustic properties of the studied ILs in AN is the size of cation of the ionic liquid. Moreover, AN interacts more strongly with N-alkyl-N-methylmorpholinium tetrafluoroborates than dimethylsulfoxide and N, N-dimethylformamide, not only by strong ion-dipole interactions, but also by packing effect.

  • Interactions of selected mono- and disaccharides with precipitated calcium carbonate particles
    • Natalia Czaplicka
    • Donata Konopacka-Łyskawa
    2019

    Calcium carbonate is a widespread compound in nature and it can be produced by living organisms in the biomineralization process. Calcite, aragonite and vaterite are anhydrous polymorphic forms of calcium carbonate, wherein the calcite is the most thermodynamically stable. Vaterite is the metastable crystalline phase, which can be a precursor of calcite and aragonite, because it can easily transformed by dissolution and re crystallization into more stable forms. Synthetic CaCO3 obtained in the precipitation process is used as an additive in many products. There are two main methods for the production of precipitated calcium carbonate (PCC) on the industrial scale, i.e. precipitation in the gas liquid system and in the liquid liquid system. Diverse PCC applications require the use of well defined particles which are characterized by the polymorph composition, the particle morphology and the crystal size distribution. The concentration of reagents, temperature, pH, duration of the reaction and the presence of inorganic and organic additives play an important role during the calcium carbonate formation and influence on the product characteristics. The effect of glucose, fructose, sucrose and trehalose on the precipitation of CaCO3 in the gas liquid system has been investigated and it has been shown that the addition of saccharides into the reaction mixture can influence the polymorph composition of produced precipitates. Saccharides are characterized by different pKa values. The lower the pKa of the saccharide, the lower the initial pH of the aqueous solution. As a consequence, it leads to a longer initial time of reaction. The presence of saccharides in the solution increases the rate of the CO2 absorption. In addition, mono- and disaccharides are able to stabilize the pre-nucleation clusters of CaCO3, i.e. prevent their aggregation and coalescence. In this work, the interaction of selected saccharides has been studied using the NP-HPLC technique. As a stationary phase vaterite and rhombohedral calcite were used, while DMSO was an eluent. Solutions of saccharides in DMSO were samples injected to the tested columns. Among the analyzed disaccharides, trehalose is characterized by the smallest capacity factor for both calcium carbonate polymorphs, thus, it exhibits the weakest adsorptive interactions. Comparing monosaccharides, fructose interacts stronger with vaterite, while higher adsorptive interactions with calcite has been observed for glucose.

  • Interactions of telomeric proteins with nucleic acids: sequence recognition on intact and oxidatively damaged telomeres
    • Miłosz Wieczór
    2019 Full text

    Telomeres are complex nucleoprotein assemblies that play a vital role in the maintenance of functional ends of linear chromosomes. Telomeric DNA, composed of tandem repeats of the 5'-TTAGGG-3' motif, solves the so-called end replication problem: as chromosomes shorten with each cell division, no information is lost, and the telomere can be re-extended. In the cell, many protein factors regulate telomere length, nuclear positioning and conformation in response to cell cycle progression and the cell's proliferative status. Several proteins bind directly to single- or double-stranded telomeric DNA to assemble the main shelterin complex or play accessory roles. However, these interactions will be perturbed when the easily oxidized telomeric DNA is exposed to oxidative stress. In my doctoral work, I used Molecular Dynamics approaches to study the dynamics of protein-DNA complex formation at telomeres on the atomistic level, arriving at the most comprehensive thermodynamic, kinetic and mechanistic description of this process to date, including the first observation of spontaneous complex formation. I then investigated the impact of oxidative lesions on telomeric proteins, showing how base modifications disrupt sequence recognition on telomeric DNA. Finally, I used quantum chemical simulations to assess the feasibility of covalent protein-DNA cross-link formation on telomeres.

  • Interdisciplinary Design Teams in Poland - Architecture as a Tool for Preventing Hospital-Acquired Infections
    • Rafał Janowicz
    2019 Advances in Intelligent Systems and Computing

    Hospital-acquired infections pose a problem, which directly affects the safe usage of healthcare facilities. On a global scale, the level of hospital-acquired infections (HAI) is estimated to affect 5–15% of those hospitalised. The World Health Organization (WHO) estimates that, on an annual basis, procedures preventing hospital-acquired infections consume 80 billion dollars [1]. In this context, it becomes important to create conditions, which will significantly reduce the occurrence of hospital-acquired infections. Preliminary research in this field has shown that a correctly functioning system reduces the risk of the occurrence of hospital-acquired infections by anywhere from 55% to as much as 70% [2]. Architectural solutions affect sanitary and hygienic safety, as well as epidemiological safety, by appropriately shaping spatial parameters. The article is set to show the relations between architectural actions and epidemiological safety, as well as presenting the need for an on-going assessment of architectural solutions by interdisciplinary teams of specialists.

  • INTERDYSCYPLINARNOŚĆ W EDUKACJI STUDENTÓW ARCHITEKTURY. NA PRZYKŁADZIE BADANIA ZJAWISK WIATROWYCH W ŚRODOWISKU ZABUDOWANYM
    • Katarzyna Zielonko-Jung
    2019

    Celem artykułu jest prezentacja możliwości włączenia badań w zakresie aerodynamiki w proces kształcenia studentów wydziałów architektury. Opisano metodę pracy ze studentami uwzględniającą badania eksperymentalne w tunelu aerodynamicznym. Pozwala ona na rozpoznanie charakteru badanych zjawisk oraz na szersze spojrzenie na interdyscyplinarność w projektowaniu architektonicznym.

  • Inter-governmental Collaborative Networks for Digital Government Innovation Transfer -Structure, Membership, Operation
    • Magdalena Ciesielska
    • Tomasz Janowski
    2019 Full text

    Digital government refers to the transformation of government organizations and their relationships with citizens, business and each other through digital technology. It entails digital innovation in processes, services, organizations, policies, etc. which are increasingly developed and tested in one country and transferred, after adaptation, to other countries. The process of innovation transfer and the underlying information and knowledge sharing increasing take place through networks. The aim of this study is to identify various forms of such networks, their structures, membership criteria and modes of operation. The study relies on the analysis of literature on innovation transfer, collaborative networks and inter-governmental collaboration, and a survey of existing inter-governmental networks for digital government innovation transfer. The key finding is that such networks are a growing form of international collaboration and an instrument in global economy.

  • INTERNATIONALIZATION OF ENTERPRISES IN KAZAKHSTAN AS AN EXAMPLE OF INTERNATIONALIZATION PATTERNS IN THE AREA OF THE EURASIAN ECONOMIC UNION.
    • Inna Suchkova
    2019

    The article aims to show the specificity of the internationalization of Kazakh enterprises, in particular, the pace, scope, intensity, and forms of their internationalization in the Eurasian Economic Union (EEU). The EEU is a relatively young grouping that was established in 2015 by the Republic of Armenia, the Republic of Belarus, the Republic of Kazakhstan, the Kyrgyz Republic and the Russian Federation. EEU creators try to give the Eurasian integration process a different direction in contrast to the structures that were created in the post-Soviet space, namely, they want use experience form European Union integration. In this paper is shown the most important effects of international economic integration, and in particular the functioning of the Eurasian Economic Union (EEU) and characterizes the economy of Kazakhstan. Furthermore, the research conducted on exporters operating on the territory of the Republic of Kazakhstan, were shown. The research sample is 108 companies including 32 small & micro (<100 employees), 33 medium (101-250 employees) and large (>250 employees), resulting in median transnationalization index at 13.3. This shows still poor internationalization, however it is growing year to year.

  • Internationalization patterns of Polish family high-tech firms
    • Nelly Daszkiewicz
    2019 Full text Entrepreneurial Business and Economics Review

    The objective of the article is to explore internationalisation patterns of family high-tech firms, especially their internationalisation motives, intensity, speed, and entry modes. The empirical part adopts a quantitative approach. The results of the survey are presented on the sample of 263 high-tech production firms from Poland, including 101 family firms. The survey was conducted in all 16 Polish regions. The calculations from obtained survey results were made using Statistica PL 10.

  • Interpretable Deep Learning Model for the Detection and Reconstruction of Dysarthric Speech
    • Daniel Korzekwa
    • Roberto Barra-Chicote
    • Bożena Kostek
    • Thomas Drugman
    • Mateusz Łajszczak
    2019 Full text

    We present a novel deep learning model for the detection and reconstruction of dysarthric speech. We train the model with a multi-task learning technique to jointly solve dysarthria detection and speech reconstruction tasks. The model key feature is a low-dimensional latent space that is meant to encode the properties of dysarthric speech. It is commonly believed that neural networks are black boxes that solve problems but do not provide interpretable outputs. On the contrary, we show that this latent space successfully encodes interpretable characteristics of dysarthria, is effective at detecting dysarthria, and that manipulation of the latent space allows the model to reconstruct healthy speech from dysarthric speech. This work can help patients and speech pathologists to improve their understanding of the condition, lead to more accurate diagnoses and aid in reconstructing healthy speech for afflicted patients.

  • Introduction to MIP synthesis, characteristics and analytical application
    • Mariusz Marć
    • Piotr Paweł Wieczorek
    2019

    One of the trends in analytical chemistry is associated with designing and developing new types of sample preparation techniques, which might significantly increase the efficiency and selectivity of the analytes isolation or/and preconcentration process. One of the most widely employed solutions are selective sorption materials, defined as molecularly imprinted polymers (MIPs), as well as the sorbents with the molecular fingerprint. Due to their simple preparation protocol, mechanical, thermal and chemical stability and selectivity, MIPs have found application as a stationary phase in separation techniques such as liquid chromatography or capillary electrophoresis, in electrochemical sensors or as a specific sorption medium in solid phase extraction (SPE) technique. The preparation of a new type of polymer material is based on a specific template molecule using selected polymerization technique and characterization of the morphological and physicochemical properties of the obtained MIP. At the end, the studies which concern the suitability and usability of the obtained MIP material under real conditions, i.e. in the analysis of environmental samples (selectivity and efficiency of the isolation and/or preconcentration of analytes from environmental samples characterized by the complex matrix) should be performed. The following chapter contains the basic information about the MIP preparation protocols and potential fields of application of these selective sorption materials in analytical and environmental chemistry.

  • Inverse and forward surrogate models for expedited design optimization of unequal-power-split patch couplers
    • Sławomir Kozieł
    • Adrian Bekasiewicz
    2019 Full text Metrology and Measurement Systems

    In the paper, a procedure for precise and expedited design optimization of unequal power split patchcouplers is proposed. Our methodology aims at identifying the coupler dimensions that correspond to thecircuit operating at the requested frequency and featuring a required power split. At the same time, thedesign process is supposed to be computationally efficient. The proposed methodology involves two typesof auxiliary models (surrogates): an inverse one, constructed from a set of reference designs optimized forparticular power split values, and a forward one which represents the circuit S-parameter gradients as afunction of the power split ratio. The inverse model directly yields the values of geometry parameters ofthe coupler for any required power split, whereas the forward model is used for a post-scaling correction ofthe circuit characteristics. For the sake of illustration, a 10-GHz circular sector patch coupler is considered.The power split ratio of the structure is re-designed within a wide range of

  • Inverse heat transfer problem solution of sounding rocket using moving window optimization
    • Adam Dąbrowski
    • Leszek Dąbrowski
    2019 Full text PLOS ONE

    An Inverse Heat Transfer Problem is solved for a sounding rocket module given its geometry and measured temperature profile. The solution is obtained via moving window optimization, a technique for solving inverse dynamics. An analysis is performed to modify the method to avoid oscillatory behavior of the resulting heat flux profile. The method parameters are tuned in relation to characteristic phases of the flight. Results are presented and correlated with measured flight data. Conclusions are drawn for better experiments for measuring heat flux on a sounding rocket skin.

  • Investigation of optical properties of Infitec and Active Stereo stereoscopic techniques for CAVE-type virtual reality systems
    • Adam Mazikowski
    2019 Full text Metrology and Measurement Systems

    In recent years, many scientific and industrial centres in the world developed virtual reality systems or laboratories. At present, among the most advanced virtual reality systems are CAVE-type (Cave Automatic Virtual Environment) installations. Such systems usually consist of four, five, or six projection screens arranged in the form of a closed or hemi-closed space. The basic task of such systems is to ensure the effect of user “immersion” in the surrounding environment. The effect of user “immersion” into virtual reality in such systems is largely dependent on optical properties of the system, especially on quality of projection of three-dimensional images. In this paper, techniques of projection of three-dimensional (3D) images in CAVE-type virtual reality systems are analysed. The requirements of these techniques for such virtual reality systems are outlined. Based on the results of measurements performed in a unique CAVE-type virtual reality laboratory equipped with two different 3D projection techniques, named Immersive 3D Visualization Lab (I3DVL), that was recently opened at the Gdańsk University of Technology, the stereoscopic parameters and colour gamut of Infitec and Active Stereo stereoscopic projection techniques are examined and discussed. The obtained results enable to estimate the projection system quality for application in CAVE-type virtual reality installations.

  • Investigation of the Combustion Processes in the Gas Turbine Module of an FPSO Operating on Associated Gas Conversion Products
    • Oleksandr Cherednichenko
    • Serhiy Serbin
    • Marek Dzida
    2019 Full text Polish Maritime Research

    In this paper, we consider the issue of thermo-chemical heat recovery of waste heat from gas turbine engines for the steam conversion of associated gas for offshore vessels. Current trends in the development of offshore infrastructure are identified, and the composition of power plants for mobile offshore drilling units and FPSO vessels is analyzed. We present the results of a comparison of power-to-volume ratio, power-to-weight ratio and efficiency for diesel and gas turbine power modules of various capacities. Mathematical modeling methods are used to analyze the parameters of an alternative gas turbine unit based on steam conversion of the associated gas, and the estimated efficiency of the energy module is shown to be 50%. In the modeling of the burning processes, the UGT 25000 serial low emission combustor is considered, and a detailed analysis of the processes in the combustor is presented, based on the application of a 35-reaction chemical mechanism. We confirm the possibility of efficient combustion of associated gas steam conversion products with different compositions, and establish that stable operation of the gas turbine combustor is possible when using fuels with low calorific values in the range 7–8 MJ/kg. It is found that the emissions of NOx and CO during operation of a gas turbine engine on the associated gas conversion products are within acceptable limits.

  • Investigation of the temperature modulation parameters on semiconductor gas sensor response
    • Łukasz Woźniak
    • Paweł Kalinowski
    • Grzegorz Jasiński
    • Piotr Jasiński
    2019

    In this work we present the results of the investigation of the sensing properties of semiconductor gas sensors with a sinusoidally modulated temperature in the presence of synthetic air (SA) and three volatile air pollutants, i.e. NH3, NO2 and SO2. The measurements were performed for different average sensor heater temperatures and the amplitude of the modulation signal. In addition, the extraction of features from the sensor response using FFT analysis was performed. The results were compared with the results obtained by approach in which the sensors were supplied with a constant value of the heater voltage. The significance of the amplitudes of higher harmonics in the FFT signal was examined in relation to the parameters of modulating signal of the sensor. The goal of this study is to investigate the performance of sensor under different ranges of the working temperature.

  • Investigation of the thermal effects in water-lubricated journal bearings with axial grooves
    • Michał Wodtke
    • Wojciech Litwin
    2019

    Water-lubricated hydrodynamic journal bearings are frequently applied as stern tube bearings due to their advantages over other bearing types. They are environmentally friendly, can operate without sealings and in conditions of low friction losses. The most popular are bearings with open axial grooves, which require, for proper operation, forced axial flow of the lubricating water. Correctly designed and operated stern tube bearings can successfully work in the fluid friction regime. The dynamic viscosity of water is relatively low compared to oil. This results in smaller minimum film thickness and lower ability to carry the load for water-lubricated bearings in comparison to oil-lubricated bearings under similar operating conditions. This is considered as a disadvantage of this bearings type. However, at the same time, the lower water viscosity limits the temperature rise in the lubricating film and reduces friction losses. For this reason, it is common practice to not include thermal effects in the theoretical analysis of water lubricated bearings and to assume an isothermal flow in the gap. On the other hand, it is known from such bearings exploitation that they can fail due to overheating, resulting in melting of polymer material of the bush. Experimental tests of water-lubricated bearings with polymeric bushes have shown that the gradual reduction of axial water flow often results in excessive temperature rise. However, this was not valid for all tested bearing materials. In this paper, an investigation of thermal effects accompanying operation of water-lubricated journal bearing is presented. For this purpose, numerical bearing model was developed using FSI (Fluid-Solid Interaction) simulation. It allowed to take into account complexity of the important phenomena for the hydrodynamic performance of the bearing, as for example: heat generation in the fluid film due to shearing, deformations of the bush or forced axial water flow. A water-lubricated bearing from theoretical investigation was also tested experimentally with the use of a full-scale test stand. Experimental investigations under limited axial water flow through the bearing revealed significant rise of the measured temperature of the bush. Measured amount of the heat generated in the bearing friction zone was much higher compared to calculated values. ture rise and enlarged heat generation.

  • Investigation of Thermoplastic Polyurethanes Synthesized via Two Different Prepolymers
    • Paulina Kasprzyk
    • Ewelina Sadowska
    • Janusz Datta
    2019 Full text JOURNAL OF POLYMERS AND THE ENVIRONMENT

    The man aim of this work was to investigate the effect of the molecular weight of polyols, mixture of prepolymers, and [NCO]/[OH] molar ratio used during the prepolymer chain extending step on the chemical structure, thermomechanical and mechanical properties, and thermal stability of thermoplastic poly(ether-urethane)s In this work thermoplastic poly(ether-urethane)s were synthesized by using polyols with a various molecular weight, 4,4′-diphenylmethane diisocyanate and bio-based glycol. Materials were obtained by a two-step method. The tests were carried out for polyurethanes obtained from a mixture of prepolymers and for reference samples. In the case of materials obtained with using mixture of prepolymers, the ratio of both prepolymers was determined on 50/50 weight percent. Soft segments of materials prepared with using mixture consist of two different polyols. The chemical structure was analyzed using FTIR spectroscopy. The Gaussian deconvolution technique was used to study the hydrogen bonding as well as to decompose carbonyl region of three peaks in various TPUs. The thermal degradation behavior was investigated by using thermogravimetric analysis at heating rates of 10 °C/min. It was confirmed that the mixture of prepolymers has an effect of the degree of phase separation, thermal stability and selected properties of synthesized thermoplastic poly(ether-urethane)s.

  • Investigation of Weigh-in-Motion Measurement Accuracy on the Basis of Steering Axle Load Spectra
    • Dawid Ryś
    2019 Full text SENSORS

    Weigh-in-motion systems are installed in pavements or on bridges to identify and reduce the number of overloaded vehicles and minimise their adverse eect on road infrastructure. Moreover, the collected trac data are used to obtain axle load characteristics, which are very useful in road infrastructure design. Practical application of data from weigh-in-motion has become more common recently, which calls for adequate attention to data quality. This issue is addressed in the presented paper. The aim of the article is to investigate the accuracy of 77 operative weigh-in-motion stations by analysing steering axle load spectra. The proposed methodology and analysis enabled the identification of scale and source of errors that occur in measurements delivered from weigh-in-motion systems. For this purpose, selected factors were investigated, including the type of axle load sensor, air temperature and vehicle speed. The results of the analysis indicated the obvious eect of the axle load sensor type on the measurement results. It was noted that systematic error increases during winter, causing underestimation of axle loads by 5% to 10% for quartz piezoelectric and bending beam load sensors, respectively. A deterioration of system accuracy is also visible when vehicle speed decreases to 30 km/h. For 25% to 35% of cases, depending on the type of sensor, random error increases for lower speeds, while it remains at a constant level at higher speeds. The analysis also delivered a standard steering axle load distribution, which can have practical meaning in the improvement of weigh-in-motion accuracy and trac data quality.