2020 - Repozytorium publikacji - Politechnika Gdańska

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Degradation of Kinematic PPP of GNSS Stations in Central Europe Caused by Medium-Scale Traveling Ionospheric Disturbances During the St. Patrick’s Day 2015 Geomagnetic Storm
- Mateusz Poniatowski
- Grzegorz Nykiel
2020 Pełny tekst Remote Sensing
In solar cycle 24, the strongest geomagnetic storm took place on March 17, 2015, when the geomagnetic activity index was as high as -223 nT. To verify the impact that the storm had on the Global Navigation Satellite System (GNSS)’s positioning accuracy and precision, we used 30-s observations from 15 reference stations located in Central Europe. For each of them, we applied kinematic precise point positioning (PPP) using gLAB software for the day of the storm and, for comparison, for a selected quiet day (13 March 2015). Based on the conducted analyses, we found out that the position root mean square (RMS) values on the day of the geomagnetic storm were significantly high and amounted to several dozen centimeters. The average RMS for the altitude coordinates was 0.58 m between 12:00 and 24:00 (GPS time), and 0.37 and 0.26 m for directions North and East, respectively. The compromised accuracy level was caused by a sudden decrease in the number of satellites used for calculations. This was due to a high number of cycle slips (CSs) detected during this period. The occurrence of these effects was strictly correlated with the appearance of traveling ionospheric disturbances (TIDs). This was proven by analyzing changes in the total electron content (TEC) estimated for each station–satellite pair.
Degree of monopoly and market power vs. price flexibility in Polish economy: empirical analysis based on COICOP classification
- Paweł Umiński
2020 Pełny tekst Oeconomia Copernicana
Research background: The issue of price flexibility is crucial in the economy both in the aspect of company theory and its macroeconomic consequences. In a number of publications, the sources of variable price flexibility are linked to the market power of enterprises as well as the market structure that has developed in a given branch. It is difficult to indicate empirical studies that would state clearly whether price flexibility depends on the degree of monopoly or the market power of enterprises. This paper concerns that particular field of study. Purpose of the article: The purpose of the paper is to present the statistical dependence of the degree of monopoly and market power vs. price flexibility in the economy. Methods: The analysis has been conducted using aggregated data concerning Polish economy in the period from 2001 to 2013, based on COICOP. The degree of monopoly indicator was the average number of companies in a given branch, following the classical models of market structures; the market power indicator was the average net revenue from sales of products per enterprise representing a given branch; the measure of price flexibility was the probability of price variation estimated using the Calvo pricing model. It is, therefore, a frequency-based approach to price flexibility. Statistical dependence was analyzed using the Spearman's rank and Kendall’s tau correlation coefficient and simple regression models. Findings & Value added: The outcomes indicate that in the case of Poland in the analyzed period there is no statistically significant relation between the degree of monopoly and price flexibility and also between the market power and price flexibility. Thus, the findings of the analysis support the studies which reject the assumption that higher degree of monopoly or higher market power of an enterprise is followed by less flexible prices.
Density functional LCAO calculations of vibrational modes and phonon density of states in the strained single-layer phosphorene
- Krzysztof Pyrchla
- Robert Bogdanowicz
2020 Pełny tekst APPLIED SURFACE SCIENCE
The paper presents an investigation of phosphorene under axial strain on the phonon density of states and vibrational modes. The studies were performed by means of density functional theory (DFT) within the linear combination of atomic orbitals (LCAO). The strained models were constructed using optimised supercell techniques. The vibrational mode spectra were estimated for strains applied for both the zigzag and armchair directions of phosphorene. This approach is an attractive candidate for the calculation the dynamical matrix of the system because its numerical complexity gradually increases together with the size of the analysed cell. The shift of peaks in the PDOS of black phosphorene is monotonic, and inversely proportional to the applied strain over the zigzag direction. This relation is valid for small strains (below 10%) of peaks corresponding to modes B2g and Ag2. For a strain applied over the armchair PDOS, the shifts are proportional to the strain. The peak shifts tend to become higher as the strain increases. This dependence is not monotonic, and is clearly more rapid for compressing strains. Moreover, the peaks shift slower for an armchair strain than for a zigzag strain, revealing its strong anisotropy.
Deodorization of model biogas by means of novel non-ionic deep eutectic solvent
- Edyta Słupek
- Patrycja Makoś
- Jacek Gębicki
2020 Pełny tekst Archives of Environmental Protection
The paper presents new non-ionic deep eutectic solvent (DES) composed of natural and non-toxic components i.e. guaiacol, camphor and levulinic acid in 1:1:3 molar ratio as a promising absorbent for removal of selected volatile organic compounds (VOCs) including dichloromethane, toluene, hexamethyldisiloxane and propionaldehyde from model biogas. The affi nity of DES for VOCs was determined as vapour-liquid coeffi cients and the results were compared with several well-known DESs based on quaternary ammonium salt as well as n-hexadecane and water. For new DES, the absorption process was carried out under dynamic conditions. The results indicate that non-ionic DES has high affi nity and capacity for VOCs being comparable to n-hexadecane. In addition, absorbed VOCs could be easily desorbed from DES using activated carbon and absorbent could be re-use minimum five times without signifi cant loss of absorption capacity
DESIGN ANALYSIS OF HYBRID GAS TURBINE - FUEL CELL POWER PLANT IN STATIONARY AND MARINE APPLICATIONS
- Tomasz Kwaśniewski
- Marian Piwowarski
2020 Pełny tekst Polish Maritime Research
The paper concerns design analysis of a hybrid gas turbine power plant with a fuel cell (stack). The aim of this work was to find the most favorable variant of the medium capacity (approximately 50 MW) hybrid system. In the article, computational analysis of two variants of such a system was carried out. The analysis let to calculate capacity, efficiency of both variants and other parameters like flu gas temperature. The paper presents that such a hybrid cycles can theoretically achieve extremely high efficiency over 60%. The most favorable one was selected for further detailed thermodynamic and flow calculations. As part of this calculation, a multi-stage axial compressor, axial turbine, fuel cell (stack) and regenerative heat exchanger were designed. Then an analysis of the profitability of the installation was carried out, which showed that the current state of development of this technology and its prices make the project unprofitable. For several years, however, tendencies of decreasing prices of fuel cells have been observed, which allows to conclude that hybrid systems will start to be created. This may apply to both stationary and marine applications. Hybrid solutions related to electrical power transmission, including fuel cells, are real and very promising for smaller car ferries and shorter ferry routes.
Design Analysis of Micro Gas Turbines in Closed Cycles
- Krzysztof Kosowski
- Marian Piwowarski
2020 Pełny tekst ENERGIES
The problems faced by designers of micro-turbines are connected with a very small volume flow rate of working media which leads to small blades’ height and high rotor speed. In the case of gas turbines this limitation can be overcome by the application of a closed cycle with very low pressure at the compressor inlet (lower than atmospheric pressure). In this way we may apply a micro gas turbine unit of accepted efficiency to work in a similar range of temperatures and the same pressure ratios, but in the range of smaller pressure values and smaller mass flow rate. Thus, we can obtain a gas turbine of a very small output but of the efficiency typical of gas turbines with a much higher power. In the paper the results of the thermodynamic calculations of the turbine cycles are discussed and the designed gas turbine flow parts are presented. Suggestions of the design solutions of micro gas turbines for different values of power output are proposed. This new approach to gas turbine arrangement makes it possible to build a gas turbine unit of a very small output and a high efficiency. The calculations of cycle and gas turbine design were performed for different cycle parameters and different working media (air, nitrogen, hydrogen, helium, xenon and carbon dioxide).
Design and characterization of apatite La9.8Si5.7Mg0.3O26±δ-based micro-tubular solid oxide fuel cells
- Sea-Fue Wang
- Yung-Fu Hsu
- Pu Hsia
- Wei-Kai Hung
- Piotr Jasiński
2020 JOURNAL OF POWER SOURCES
In this study, electrolyte-supported (Cell A) and anode-supported (Cell B) micro-tubular solid oxide fuel cells (SOFCs) based on the La9.8Si5.7Mg0.3O26±δ (LSMO) electrolyte is built through an extrusion and dip-coating processes. The formulations and process conditions for these cells are established and optimized. Both cell configurations show no visible delamination or cracking, and reaction zones and inter-diffusion of any species are absent at the interfaces of the multilayer structures. The micro-tubes LSMO and LSMO-NiO have a high flexural strength of ~70 MPa. Cell B with a 3.33 mm outer diameter, a 12 μm LSMO electrolyte layer, a ~300 μm LSMO-NiO functional anode layer, a 9 μm NiO current-collector layer, and a 44 μm La0.6Sr0.4Co0.2Fe0.8O3-δ cathode layer has superior electrochemical performances than does Cell A. The polarization resistance (Rp) value for Cell B accounts for 67.6% and 50.5% of the total resistance (Rt) value at 700 °C and 895 °C, respectively, suggesting that Rp dominates at low temperatures and ohmic resistance (Ro) and Rp values are equally important at high temperatures. Cell B's open-circuit voltages (OCVs) are slightly below the theoretical value due to poor sealing of cells. The maximum power densities (MPDs) of Cell B, increase with increasing operating temperature and are 0.12, 0.24, and 0.27 W cm−2 at 750 °C, 850 °C, and 895 °C, respectively. Compared to Cell A, Cell B displays lower OCV values but higher MPD (0.27 W cm−2 vs. 0.06 W cm−2 at 895 °C) due to its significantly lower Ro value, mainly due to the thin layer of LSMO electrolytes.
Design and Evaluation of the Platform for Weight-Shifting Exercises with Compensatory Forces Monitoring
- Wiktor Sieklicki
- Robert Barański
- Szymon Grocholski
- Patrycja Matejek
- Mateusz Dyrda
2020 Pełny tekst Communications in Computer and Information Science
Details of a platform for the rehabilitation of people with severe balance impairment are discussed in the paper. Based upon a commercially available static parapodium, modified to fit force sensors, this device is designed to give a new, safe tool to physiotherapists. It is designed for the patients who cannot maintain equilibrium during a bipedal stance and need to hold to or lean on something during the rehabilitation. Visual, real-time information about weight distribution between left and right leg as well as the information about the force applied to the pillows supporting the patient's body is provided to the patient with help of a LED display. The control system allows registering forces applied by the patient to the device and analyze them after the therapy. The results of a preliminary evaluation of the device are presented in the paper with four healthy and one Cerebral Palsy ataxic participants. Two exercise scenarios are tested showing significant dependence between balance impairment and compensatory forces measured by the device, as well as a notable difference in how the subject strives for better results if the visual feedback is provided.
DESIGN AND THEORETICAL ANALYSIS OF A PROTOTYPE TILTING-PAD RADIAL BEARING WITH ADJUSTABLE CLEARANCE
- Artur Olszewski
- Grzegorz Żywica
- Tomasz Żochowski
2020 Pełny tekst TRIBOLOGIA
The article introduces a design and analysis results of a prototype ORC (organic Rankine cycle) turbo generator rotor assembly of 300kW power, supported by tilting-pad bearings of original design. The calculations were performed for a prototype turbo generator rotor. The shaft of this machine is supported with two radial bearings, lubricated with an unusual lubricant – a low-boiling-point agent. The main objective of the presented research was to perform calculations verifying the feasibility of using hydrodynamic tilting-pad radial bearings with a low-viscosity lubricant to support a rather massive and high-speed rotor of the developed turbo generator and to determine the geometry and design of the bearings which would ensure optimal kinetostatic and dynamic properties of the rotating system, while simultaneously providing ease of assembly and smooth clearance adjustment.
Design aspects of a low-cost prosthetic arm for people with severe movement disabilities
- Tomasz Kocejko
- Radosław Węglarski
- Tomasz Zubowicz
- Jacek Rumiński
- Jerzy Wtorek
- Krzysztof Armiński
2020
In this paper the main aspects of mechanical design behind the low-cost prosthetic arm are presented. The fundamentals of a proper design has been defined to obtain functional 3D printed 5 degree of freedom (DOF) prosthesis. The designed prosthetic arm is a part of the hybrid interface with eye tracking movement control. The main focus was to create affordable but usable prosthesis which corresponds in size and weights to the human arm. The iterative process (starting from the final segment of the arm) was used to design fully functioning arm. All the elements were evaluated regarding total weight and the maximum load that can be carried by the arm. The result of this work is a prototype that weighs below 6kg and has a range of motion comparable to the human's arm. Final product is able to freely move an object of a total weight of 1 kg. All the mechanical parts of the designed arm were 3D printed which therefore presented construction can be adopted by people with different disabilities and (when connected to interfaces like EEG, EMG or eye tracking) provide support in everyday life activities.
DESIGN LOGICAL LINGUISTIC MODELS TO CALCULATE NECESSITY IN TRUCKS DURING AGRICULTURAL CARGOES LOGISTICS USING FUZZY LOGIC
- Ievgen Medvediev
- Dmitriy Muzylyov
- Natalya Shramenko
- Pavlo Nosko
- Peter Eliseyev
- Vitalii Ivanov
2020 Pełny tekst Acta Logistica
: The study is aimed to develop the logic-linguistic models to design a number of rules for the correct calculation of the vehicles needed, taking into account the technical, technological, and weather and climate conditions of the harvesting and transport complex. The article has shown that the construction of the design of logic-linguistic models was not performed earlier to solve the problem of the agro-industrial production transportation support, considering the opportunity of forecasting size of influences of the weather and climatic factors on improving the productivity of the harvesting and transport complex elements. It is determined that the experience of applying the fuzzy logic theory in many practice situations confirms the universality of the mathematical apparatus. This toolkit provides better results than classical approaches (set theory, probability theory). This aspect indicates the expediency of the chosen mathematical apparatus for solving the tasks. The article using fuzzy logic explores the relationship and interdependence of technical, technological factors and weather and climate conditions for modeling transport support in harvesting and transport complex. Fuzzification of the parameters is carried out, based on the compiled equations using trapezoidal and triangular membership functions. The set of rules necessary for the creation of logical-linguistic models (LLM) for each factor has been arranged. LLMs were developed for dependent parameters, which will allow further modeling of the transport support of the harvesting and transport complex in the Fuzzy Logic Toolbox application of the MATLAB package.
Design of battery charging system update for glider launcher
- Wojciech Rosiński
- Szymon Potrykus
- Michał Michna
2020 Pełny tekst Archives of Electrical Engineering
This paper presents an innovative solution for increasing life of lead-acid batteries used in a glider launcher. The study is focused on upgrading a charging system instead of a costly full replacement of it. Based on literature review, the advanced three-stage charging profile was indicated. The new topology of the power converter was proposed and a simulation model was developed. A simulation study was performed which leads to a conclusion that the suggested solution can be successfully applied to the studied device. As a result, the conclusion of this work is the recommendation for modification of the launching system with an additional converter enabling 3 stage charging.
Design of new cholinesterase inhibitors based on phosphorus analogs of tacrine as potential anti-Alzheimer’s disease agents
- Maja Przybyłowska
- Krystyna Dzierzbicka
- Iwona Inkielewicz-Stępniak
2020
Based on the analysis of the determined free binding energy (using the AutoDock Vina 1.1.2 docking program), the most potent cholinesterase inhibitors were selected. Moreover, studies of 3D visualization of the results of molecular modeling led to the identification of potential sites for the interaction of new potential inhibitors with amino acid residues building active sites of investigated cholinesterases.
Design of optimal state feedback controller with observer for multidimensional electrical system
- Robert Piotrowski
- Maciej Szafrański
- Konrad Żuk
2020 Pełny tekst Przegląd Elektrotechniczny
From the control point of view, two-input-two-output RC electrical system is a linear and multidimensional system. In this paper, integral control and closed-loop observer are verified whether they can be used and designed. To verify this, Kalman tests are made. These structures are presented and discussed. Integral Control is tested with some base disturbances impact and checked whether it can handle them. The estimated values from the observer are compared with the original states. Simulation tests and real tests of control systems are presented.
Design of poroelastic wearing course with the use of direct shear test
- Dawid Ryś
- Piotr Jaskuła
- Marcin Stienss
- Cezary Szydłowski
2020 Pełny tekst
Poroelastic Road Surfaces (PERS) are characterized by porous structure with at least 20% of air void content and stiffness almost 10 times lower than typical asphalt course. Such properties enable noise reduction up to 12 dB in comparison to SMA 11 mixture. However, the main disadvantage of previously used poroelastic mixtures, based on resin type binders, was their low durability, which resulted in raveling and delamination from the lower layer. This paper presents initial results obtained for new type of PERS mixture, based on highly modified bitumen as a binder instead of resin type binder. The direct shear test was applied to estimate resistance of the mixture to raveling as well as to evaluate interlayer bond quality. Observations of first short test sections with different compositions of new PERS mixtures yielded promising results.
Design of power cable lines partially exposed to direct solar radiation – special aspects
- Stanisław Czapp
- Seweryn Szultka
- Adam Tomaszewski
2020 Pełny tekst ENERGIES
Power cable lines are usually buried in the ground. However, in some cases, their ending sections are mounted along the supports of overhead lines. This leads to a situation where the cables are exposed to direct solar radiation and, consequentially, overheat. The paper presents the advanced computer modelling of power cables’ heating, considering their insolation as well as the effect of wind. The temperature and current-carrying capacity of power cables – during exposure to direct solar radiation – are evaluated. An effective method of limiting the unfavourable impact of the sun is discussed. In the presence of solar radiation, the proposed method enables a significant increase in the power cables current-carrying capacity.
Design of Resilient Vehicle-to-Infrastructure Systems
- Jacek Rak
- Magnus Jonsson
- Alexey Vinel
- Karol Jurczenia
2020
Vehicular ad hoc networks (VANETs) have recently gained noticeable attention due to advantages in improving road traffic safety, shaping the road traffic and providing infotainment opportunities to travellers. However, transmission characteristics following from the IEEE 802.11p standard and the high mobility of VANET nodes remarkably reduce the lifetime, reach and capacity of wireless links, and often lead to simultaneous disruptions of communications at multiple links. In this chapter, we present a set of solutions to enhance the performance of VANETs (which can be applied independently of particular applications) concerning (a) design of the VANET infrastructure (location of road-side units—RSUs and gateways), (b) communications along vehicle-to-infrastructure (V2I) links and (c) resilience of VANET services to malicious human activities.
Design, synthesis and high antitumor potential of new unsymmetrical bisacridine derivatives towards human solid tumors, specifically pancreatic cancers and their unique ability to stabilize DNA G-quadruplexes
- Ewa Paluszkiewicz
- Barbara Horowska
- Barbara Borowa-Mazgaj
- Grażyna Peszyńska-Sularz
- Jolanta Paradziej-Łukowicz
- Ewa Augustin
- Jerzy Konopa
- Zofia Mazerska
2020 EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
New promising unsymmetrical bisacridine derivatives (UAs), have been developed. Three groupsincluding 36 compounds were synthesized by the condensation of 4-nitro or 4-methylacridinone, imi-dazoacridinone and triazoloacridinone derivatives with 1-nitroacridine compounds linked with anaminoalkyl chain. Cytotoxicity screening revealed the high potency of these compounds against severaltumor cell lines. Particularly, imidazoacridinone-1-nitroacridine dimers strongly inhibited pancreaticPanc-1, Mia-Pa-Ca-2, Capan-2 and prostate cancer DU-145 cell growth. The studied compounds showedvery strong antitumor activity (T/C>300%) against Walker 256 rat adenocarcinoma. The selected 26 UAswere tested against 12 human tumor xenografts in nude mice, including colon, breast, prostate andpancreatic cancers. The studies on the molecular mechanism of action demonstrated that these un-symmetrical dimers significantly responded to the presence of G-quadruplex not to dsDNA. Structure-activity relationships for UAs potency to G-quadruplex stabilization indicated that thermal stability ofthis drug-G-quadruplex complex depended not only on the structure of heterocyclic rings, but also onthe properties of dialkylamino chains of the ring linkers. In conclusion, the presented studies identifiedthe new group of effective antitumor agents against solid human tumors, particularly pancreatic Panc-1,BxPC-3 and Mia-Pa-Ca-2 and strongly indicated their distinctive interactions with DNA. In contrast tomonomers, G-quadruplex not dsDNA is proposed to be thefirst molecular target for these compounds.
Design thinking (DT) for the design and planning education of engineer-architects
- Dorota Kamrowska-Załuska
- Tomasz Parteka
2020 Pełny tekst World Transactions on Engineering and Technology Education
Engineers are facing new challenges connected with globalisation, digitisation and the increased complexity of the design process. This calls for new, more interdisciplinary and user-oriented approaches to problem- solving. In this article, the authors analyse design thinking (DT) as a method to support the education of engineers specialising in architecture and urban planning. Identified in this study are the opportunities this method offers to solve design and planning problems, as well as the limitations of the method. It is based on experience gained, while conducting regional and urban planning courses for engineers in the Faculty of Architecture at Gdańsk University of Technology (FA-GUT). Gdańsk, Poland, The design thinking method is not a remedy for all design problems, but the user-centric, iterative and experimental approach that can help to prepare future professionals to conduct participatory design in the changing conditions of the modern world.
Designing control strategies of aeration system in biological WWTP
- Robert Piotrowski
- Tomasz Ujazdowski
2020 Pełny tekst ENERGIES
The paper presents the complete design processes of a novel aeration control systems in the SBR (Sequencing Batch Reactor) wastewater treatment plant (WWTP). Due to large energy expense and high influence on biological processes, the aeration system plays a key role in WWTP operation. The paper considers the aeration system for a biological WWTP located in the northeast of Poland. This system consists of blowers, the main collector pipeline, three aeration lines with different diameters and lengths, and diffusers. Classical control systems applied for this type of installation are based on PID (Proportional–Integral–Derivative) controllers, the settings of which are often found experimentally. The article presents the optimization of these settings and the design of an alternative control algorithm – the fuzzy controller.