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Gdańsk University of Technology

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Publications from the year 2018

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  • Types of Surface Impurities versus the Quality of Brazed Joints
    • Jacek Tomków
    • Jacek Haras
    2018 Full text Biuletyn Instytutu Spawalnictwa w Gliwicach

    Brazing is one of the primary joining processes increasingly often applied in industry. Because of their mechanical properties, overlap joints are particularly popular when making brazed structures. The use of brazed joints in structures of critical importance requires that particular attention be paid to joint quality, e.g. by the appropriate cleaning of surfaces to be joined. The article presents results of non-destructive tests of brazed joints made in steel S235JRG2. Surfaces used in the tests were deliberately contaminated to simulate the presence of welding imperfections. Afterwards, the test specimens were subjected to non-destructive (visual and radiographic) tests aimed to determine the effect of surface impurities on the quality of brazed joints.

  • UAV Design and Construction for Real Time Photogrammetry and Visual Navigation
    • Paweł Burdziakowski
    2018 Full text

    A unmanned aerial vehicles applications in photogrammetry have increased rapidly last years. A fast data gathering and processing in real time in some cases become crucial and desired in some application. In the paper, a real time solution is proposed. A real time photogrammetry from UAV is proposed, where image data are gathered and processed on board UAV and finally reconstructed 3D model and measurements are delivered. The paper presents the design of sUAV (small unmanned air vehicle) for real time photogrammetry, visual navigation, real-time spectral data processing. Construction is based on newly designed quadcopter frame based on the experience and previous research, using CAD/CAM. No image data are transferred out of the board and overall photogrammetry process is calculated on board. Finally three dimensional measurements are delivered to the user in the same time, as sUAV flies, or in specified time just after the sUAV has landed.

  • UAV IN TODAYS PHOTOGRAMMETRY – APPLICATION AREAS AND CHALLENGES
    • Paweł Burdziakowski
    2018

    There a few important factors, that nowadays, unmanned aerial vehicles (UAV) are used by wider community, and for cases and applications, that cannot be performed never before. Small UAVs, as a photogrammetry measurement tool provide flexibility, reliability, are safe and easy to use, can be deployed in minutes, initial measurement can be delivered yet on the field, and final accurate measurements are calculated in a very short time, even using online services. A numerous cases was studied on Department of Geodesy at Gdansk University of Technology using popular and commercial drones. All cases was analyzed using modern methods, and the results was compared to laser scans measurements. The paper presents results, including challenges and conclusions for each studied case, especially for geodesy, architecture, heritage conservation, civil engineering, police work, forensic analysis and natural science.

  • UKŁAD I PROGRAM DO WYZNACZANIA PARAMETRÓW SCHEMATU ZASTĘPCZEGO SUPERKONDENSATORA
    • Karol Przybylski
    • Arkadiusz Szewczyk
    2018 Full text Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    W pracy przedstawiono prototyp urządzenia do wyznaczania parametrów schematu zastępczego superkondensatora na podstawie jego charakterystyk ładowania i rozładowania. Urządzenie składa się ze sterowanego źródła prądowego do ładowania i rozładowywania superkondensatora, przetwornika analogowo-cyfrowego do pomiaru prądu i napięcia w trakcie eksperymentu oraz mikroprocesora do sterowania pomiarem i komunikacji z komputerem na którym uruchomiony jest program sterujący. W celu sprawdzenia poprawności działania wykonanego prototypu urządzenia przeprowadzono szereg pomiarów dla wybranych dostępnych w handlu superkondensatorów. Przeprowadzone badania potwierdziły poprawność pracy zaprojektowanego układu.

  • Ulga podatkowa jako mechanizm stymulowania zachowań mikro i małych przedsiębiorstw. Prezentacja wyników badań
    • Piotr Kasprzak
    2018 Full text Finanse, Rynki Finansowe, Ubezpieczenia

    Cel – Celem niniejszego artykułu jest prezentacja wyników badań przeprowadzonych w okresie styczeń–kwiecień 2018 roku. Celem badania było zdefiniowanie, przedstawienie i określenie stymulacyjnej roli podatku dochodowego realizowanej za pośrednictwem ulg i zwolnień podatkowych w polskim systemie podatkowym w stosunku do przedsiębiorstw sektora MŚP. Autor za cel dodatkowy postawił wskazanie możliwości, z których mogą korzystać przedsiębiorstwa sektora MŚP w zakresie mechanizmów ulg i zwolnień oraz określenie świadomości polskich przedsiębiorstw sektora mikro i małych firm w zakresie możliwości korzystania z ulg i preferencji podatkowych, a także zidentyfikowanie przesłanek i barier stosowania mechanizmów ulg i zwolnień podatkowych. Metodologia badania – Metodyka obejmuje empiryczne badania o charakterze jakościowym zrealizowane za pośrednictwem kwestionariusza skierowanego do sektora mikro i małych przedsiębiorstw. Niniejszy artykuł uzupełniono o przeprowadzone studia literaturowe. Wynik – Wyniki przeprowadzonego badania wskazują, iż poziom wykorzystania ulg i zwolnień wśród przedsiębiorstw sektora MŚP jest niski. Najczęściej spowodowane jest to zarówno brakiem wiedzy w tym zakresie, jak i wysokim poziomem skomplikowania procedur biurokratycznych. Badani przedsiębiorcy potrafią jednak co do zasady wskazać wybrane metody obniżania zobowiązań podatkowych z wykorzystaniem ulg i zwolnień. Wyniki badania wskazują także postulowany przez przedsiębiorców kierunek i zakres zmian w omawianym obszarze. Oryginalność/wartość – Przeprowadzone przez autora badania miały charakter pilotażowy, a ich wyniki mogą stanowić bazę do dalszych, bardziej pogłębionych analiz.

  • Unassisted formation of hemiaminal ether from 4-aminopyridine and o-vanillin - experimental and theoretical study
    • Agnieszka Mielcarek
    • Aleksandra Wiśniewska
    • Anna Dołęga
    2018 Full text STRUCTURAL CHEMISTRY

    The reactions between o-vanillin and three isomeric aminopyridines lead to imines of diverse spatial conformation and reactivity. The direct products of these simple reactions carried out in methanol are either imine compounds formed in the reactions of 2- amino- and 3-aminopyridine with o-vanillin or the α-aminoether formed in the reaction of o-vanillin with 4-aminopyridine. The Schiff-type derivative of 4-aminopyridine and o-vanillin, which is described in this paper for the first time, is very reactive and can only be obtained indirectly from the α-aminoether in anhydrous conditions. All compounds are characterized by X-ray diffraction and FT-IR and NMR spectroscopies. The DFT calculations at all-electron BLYP/Q4ZP level of theory are utilized to explain the differences between the reactivity of isomeric aminopyridines and their imine derivatives.

  • Uncertainty of the liquid mass flow measurement using the orifice plate
    • Anna Golijanek-Jędrzejczyk
    • Dariusz Świsulski
    • Robert Hanus
    • Marcin Zych
    • Leszek Petryka
    2018 Full text FLOW MEASUREMENT AND INSTRUMENTATION

    The article presents an estimation of measurement uncertainty of a liquid mass flow using the orifice plate. This subject is essential because of the widespread use of this type of flow meters. Not only the quantitative estimation but also the qualitative results of those measurements are important. To achieve these results the authors of the paper propose to use the theory of uncertainty. The article shows the analysis of the measurement uncertainty using two methods: one based on the ‘Guide to the expression of uncertainty in measurement’ (GUM) of the International Organization for Standardization by means of the law of propagation of uncertainty, and the second one by means of the Monte Carlo numerical method. The paper presents a comparative analysis of the results obtained by employing both of these methods for the centric and eccentric orifice plate. In both of the examples, the resulting uncertainty of flow measurement is approximately 1%. The uncertainty determined by the analytical method was higher than what was obtained from the Monte Carlo simulations with a difference of 0.04%.

  • Underwater Navigation System Based on Doppler Shifts of a Continuous Wave
    • Zawisza Ostrowski
    • Jacek Marszal
    • Roman Salamon
    2018

    The paper describes a concept of an underwater navigation system designed to determine the location and speed of its ROVs or divers. Conducted by the Department of Marine Electronic Systems at the Gdansk University of Technology for several years, research has focused on navigation systems which determine positions on the basis of Doppler shifts of echo signals reflected from a moving object. This article presents a different version of such a system. With a source of a sinusoidal acoustic wave placed on a moving object, four hydrophones, transmitting and receiving electronics and a computer, the system determines Doppler deviations of the received signals and calculates the position and speed of the moving object. Simulation studies and experiment results have shown that the system can offer an alternative solution for tracking its underwater objects.

  • Uniform sampling in constrained domains for low-cost surrogate modeling of antenna input characteristics
    • Sławomir Kozieł
    • Ari Sigurdsson
    • Stanisław Szczepański
    2018 Full text IEEE Antennas and Wireless Propagation Letters

    In this letter, a design of experiments technique that permits uniform sampling in constrained domains is proposed. The discussed method is applied to generate training data for construction of fast replacement models (surrogates) of antenna input characteristics. The modeling process is design-oriented with the surrogate domain spanned by a set of reference designs optimized with respect to the performance figures and/or operating conditions that are of interest. The reference designs are triangulated and the resulting simplexes are extended in orthogonal directions. Our methodology is demonstrated using two examples: a dual-band dipole and an ultra-wideband monopole. The results indicate that the proposed sampling technique leads to considerable improvement of the surrogate model predictive power as compared to random sampling. Numerical results are supported by application studies (antenna optimization) and experimental validation.

  • UN’IPERTROFIA INEVITABILE? LA MOBILITAZIONE INDUSTRIALE E LA TRASFORMAZIONE DELL’APPARATO AMMINISTRATIVO PER LO SFORZO BELLICO
    • Luciano Segreto
    2018

    Il capitolo esamina le trasformazioni dell'apparato amministrativo in relazione alle esigenze dello sforzo bellico

  • Uniwersalna metoda obliczania wartości prądów w przewodach odgromowych linii napowietrznych
    • Jacek Klucznik
    2018 elektro.info

    W artykule przedstawiono nowatorską metodę obliczania wartości prądów płynących w przewodach odgromowych linii elektroenergetycznych w czasie zwarć. Metoda może być stosowana dla złożonych układów sieciowych, składających się z kilku stacji oraz różnych typów linii. Analizowane mogą być linie jedno- i dwutorowe z jednym bądź dwoma przewodami odgromowymi. Metoda pozwala na dobór przewodów odgromowych pod względem wytrzymałości cieplnej z mniejszym ryzykiem niepewności niż powszechnie stosowane metody. Prezentowana metoda obliczeniowa pozwala również na ocenę ochrony przeciwporażeniowej linii, poprzez wyznaczenie wartości prądów płynących w uziomach słupów.

  • Unravelling the role of electron–hole pair spin in exciton dissociation in squaraine-based organic solar cells by magneto-photocurrent measurements
    • Maciej Klein
    • Sayani Majumdar
    • Paweł Zassowski
    • Waldemar Stampor
    2018 Journal of Materials Chemistry C

    A high absorption coefficient and narrow absorption bands in squaraine (SQ) dyes have resulted in rapidly growing interest in them as a donor material in photovoltaic devices. The exciton dissociation process in organic systems proceeds via a multistep mechanism where the electron–hole pairs (charge transfer states) involved in the current generation process determine the recombination losses and subsequently limit the overall performance of organic solar cells. In this work, these basic electronic processes are investigated by magneto-photocurrent measurements (MPC, the photocurrent change induced by the external magnetic field) of SQ:PC60BM bulk-heterojunction solar cells with varying electron acceptor concentrations under magnetic fields up to 9 T and at different temperatures. Under a weak external magnetic field, the change in photocurrent is due to electron and hole (e–h) pairs that experience a modulating hyperfine interaction associated with nuclear (mainly proton) magnetic moment, while in strong magnetic fields the photocurrent is affected by the Δg mechanism with spin dephasing due to different Lande factors of the electron and hole entities (Δg ≈ 10−3). To consistently interpret the amplitudes and lineshapes of the MPC signals at various temperatures, charge carrier hopping in a disordered environment competing with the magnetic dipole spin precession is proposed. The requirements for efficient small-molecular weight organic:fullerene bulk-heterojunction solar cells are briefly discussed.

  • Unusual Influence of Fluorinated Anions on the Stretching Vibrations of Liquid Water
    • Maciej Śmiechowski
    2018 Full text JOURNAL OF PHYSICAL CHEMISTRY B

    Infrared (IR) spectroscopy is a commonly used and invaluable tool in the studies of solvation phenomena in aqueous solutions. Concurrently, ab initio molecular dynamics (AIMD) simulations deliver the solvation shell picture at a molecular detail level and allow for a consistent decomposition of the theoretical IR spectrum into underlying spatial correlations. Here, we demonstrate how the novel spectral decomposition techniques can extract important information from the computed IR spectra of aqueous solutions of BF<sub>4</sub><sup>−</sup> and PF<sub>6</sub><sup>−</sup>, interesting weakly coordinating anions that have been known for a long time to alter the IR spectrum of water in an unusual manner. The distance-dependent spectra of both ions are analyzed using the spectral similarity method that provides a quantitative picture of both the spectrum of the solute-affected solvent and the number of solvent molecules thus altered. We find, in accordance with previous experiments, a considerable blue shift of the ν<sub>OH</sub> stretching band of liquid water by 264 cm<sup>−1</sup> for BF<sub>4</sub><sup>−</sup> and 306 cm<sup>−1</sup> for PF<sub>6</sub><sup>−</sup> , with the affected numbers being 3.7 and 4.2, respectively. Considering also the additional information on solute−solvent dipolar couplings delivered by radially and spatially resolved IR spectra, the computational IR spectroscopy based on AIMD simulations is shown to be a viable predictive tool with strong interpretative power.

  • Up-conversion white emission and other luminescence properties of a YAG:Yb2O3·Tm2O3·Ho2O3@SiO2 glass-nanocomposite
    • Andrzej M. Kłonkowski
    • Benedykt Kukliński
    • Mariusz Kubus
    • Jacek Ryl
    • Karol Szczodrowski
    • Dorota Wileńska
    • H. Jurgen Meyer
    2018 Full text RSC Advances

    We report on a glass-nanocomposite material consisting of yttrium aluminum garnet (Y3Al5O12, YAG) nanocrystals co-doped with Yb3+, Tm3+ and Ho3+ ions as well as entrapped into a SiO2 xerogel. This 94YAG·5Yb2O3·0.8Tm2O3·0.2Ho2O3@SiO2 (abbr. YAG:YbTmHo@SiO2) nanocomposite material has been prepared by sol–gel procedure. Its structure and morphology has been characterized by means of X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques as well as energy dispersive X-ray (EDX), X-ray photoelectron (XPS) and luminescence spectroscopies. The luminescent glass-nanocomposite exhibited an up-conversion effect under λexc = 980 nm and emission when excited under 355 nm in steady-state conditions. Then time-resolved luminescence emission was observed, when the sample was excited at 290 and 355 nm by a pulse laser. Average decay times for the SiO2 matrix and for some transitions of the Tm3+ and Ho3+ dopants present in the YAG:YbTmHo@SiO2 material have been evaluated. The luminescent nanocomposite when excited under 290 or 355 nm wavelengths in both conditions emits blue light. However, the nanocomposite is promising as a single-source white-light phosphor owing to its up-conversion luminescence under 980 nm excitation. Such optical features make the studied material an alternative phosphor.

  • Updating the Coupling Algorithm between HYDRUS and MODFLOW in the HYDRUS Package for MODFLOW
    • Sahila Beegum
    • Jiří Šimůnek
    • Adam Szymkiewicz
    • K Sudheer
    • Indumathi Nambi
    2018 Full text VADOSE ZONE JOURNAL

    The HYDRUS-based flow package for MODFLOW (the HPM or the HYDRUS package) is an existing unsaturated zone flow package for MODFLOW. In MODFLOW with the HPM, the groundwater modeling domain is discretized into regular grids that can be combined into multiple zones based on similarities in soil hydrology, topographical characteristics, and the depth to the groundwater. Each of these zones is assigned one unsaturated soil profile (the HPM profile). In this model, after every MODFLOW time step, the flux at the bottom of the HPM profile is given as an input recharge flux to MODFLOW. MODFLOW simulates groundwater flow, and the water table depth at the end of the MODFLOW time step is assigned as the bottom boundary condition in the HPM profile. The current coupling algorithm assumes that the groundwater table in the HPM profile remains constant throughout the entire MODFLOW time step. This results in unrealistic sudden inflow and/or outflow fluxes at the bottom of the HPM profile after every time step. The objective of this study was to develop a methodology to eliminate the error in the determination of the recharge flux at the bottom of the HPM profile. This was achieved by updating or modifying the pressure head profile in the HPM profile after every MODFLOW time step. The effectiveness and the applicability of the new coupling algorithm were evaluated using different case studies. The new coupling algorithm is effective in eliminating unrealistic sudden variations in the bottom flux in the HPM profiles.

  • Urban Freight Transport Demand Modelling and Data Availability Constraints
    • Daniel Kaszubowski
    2018

    The paper provides a review of urban freight transport demand modelling approaches confronted with constrains regarding adequate data provision from a perspective of the local authorities. Demand estimation models has been selected as a reference because they are the most representative in terms of inclusion of urban freight indicators which can be transformed into a decision-support tool for evaluation of freight measures. The main concern is to find a balance between an effort required to create a reliable urban freight analysis framework and transport policy’s objectives. Delivery-based models has been considered as the most promising in terms of possible results and ability to represent different aspects of urban supply chains in a coherent way. As they use a vehicle movement as a descriptor, the results can be presented in measurable way in terms of general transport planning framework.

  • Urban Prototyping in CAVE Cooperation Between the Academy of Fine Arts in Gdansk and the Gdansk University of Technology
    • Iwona Dzierżko-Bukal
    • Jacek Lebiedź
    2018

    The paper describes results of cooperation between the Passive Architecture Laboratory at the Academy of Fine Arts in Gdańsk and the Immersive 3D Visualization Lab at the Gdańsk University of Technology. The authors as the design supervisors (respectively for a team of architects and a team of IT specialists) present advantages and disadvantages of urban design with use of virtual reality.

  • Urban space recovery. Landscape-beneficial solutions in new estates built in post-industrial and post-military areas in Bristol, Poznań and Gdańsk
    • Elżbieta Raszeja
    • Joanna Badach
    2018 Full text Miscellanea Geographica

    The limitation of territorial expansion and the implementation of the idea of a compact city are generally accepted paradigms of spatial development of contemporary cities. In consequence, actions are taken to improve the quality of city landscape and revitalise vacant areas. This study approaches the process of city regeneration as transformation and supplementation of the existing urban structure as well as creation of multifunctional, structurally, socially and ecologically sustainable spaces. The article presents the problem of creation of new-inner city residential areas. The study was conducted on three housing estates located in post-industrial and post-military areas: Harbourside Development in Bristol (UK), City Park and Ułańskie Estate in Poznań (Poland) and Browar Gdański in Gdańsk (Poland). The article includes analyses of relations between the estates and their surroundings, spatial structure parameters and architectural, urban and scenic characteristics. It includes assessment of the legibility, consistency, diversity and quality of the urban landscape.

  • Urbanistyka i architektura dawnego garnizonu w Gdańsku Strzyży
    • Aleksander Piwek
    2018

    Przedstawione zostały dzieje budowy i rozwoju urbanistycznego dawnych koszar w Gdańsku-Strzyży. Scharakteryzowano także architekturę poszczególnych obiektów z podaniem ich pierwotnych jak i późniejszych funkcji. Opisano szczegółowo d. koszary jednostki taborów, I. i 2. Regimentu Huzarów Przybocznych, późniejsze uzupełnienia zespołu koszar, zabudowę składu wozowni, także zabudowę wojskową pozostającą poza obrębem koszar.

  • Urine headspace analysis in medical diagnostics
    • Kaja Kalinowska
    • Jacek Namieśnik
    2018 Full text World Scientific News

    The analysis of the volatile organic compounds in the bodily fluids such as urine may provide useful information on the patients’ general health. The potential application of urine headspace analysis could facilitate the diagnostics of various diseases such as metabolic disorders, urinary tract diseases and gastrointestinal conditions. Described in this paper are the currently available techniques of urine sample analysis as well as their different application in medical diagnostics.