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Gdańsk University of Technology

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Publications from the year 2019

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  • Identification of Shear Modulus Parameters of Half-space Inhomogeneous by Depth
    • Vladimir Zelentsov
    • Polina Lapina
    • Victor Eremeev
    2019 Full text AIP Conference Proceedings

    The paper propose a method for determining of the parameters of the exponential shear modulus of a functionally graded half-space based on the solution of the problem of a pure shear of an elastic functionally graded half-space by a strip punch. The solution of the integral equation of the contact problem is constructed by asymptotic methods with respect to the dimensionless parameter. The dependence of contact stresses on the parameters of the shear modulus is analyzed. The determination of the parameters of the shear modulus of a functionally graded half-space is based on the values of shear stresses at the contact. By choosing proper shear modulus parameters of the functionally graded half-space, “approximately homogeneous” area inside of the functionally graded half-space are developed.

  • Identifying Selected Tram Transport Risks
    • Marcin Budzyński
    • Agnieszka Tubis
    • Kazimierz Jamroz
    2019 Full text IOP Conference Series: Materials Science and Engineering

    In the area of transport infrastructure risks, infrastructure is inspected for safety. It is an element of transport safety management based on risk management and forms part of preventative activities and measures. As regards tram infrastructure which is a component of urban transport infrastructure, there are potential collisions with cars, cyclists and pedestrians. Data from Gdansk Buses and Trams (GAiT) shows that between 2012 and 2016 on average there were about 650 incidents involving trams (collisions and accidents). The objective of inspection will be to identify sources of hazards which may lead to tram accidents or indirectly when tram infrastructuremay contribute to accidents not involving trams. The objective of the work is to identify the risks to urban public transport operation with a special focus on trams and to formulate recommendations on how to improve its quality and safety

  • Identyfikacja wad powierzchni tocznej szyn za pomocą sygnału wibroakustycznego
    • Roksana Licow
    • Franciszek Tomaszewski
    2019 Full text Problemy Kolejnictwa

    W artykule przedstawiono koncepcję metody identyfikacji najczęściej występujących wad powierzchni tocznej szyn za pomocą sygnałów wibroakustycznych. Opisano badane wady szyn take, jak: squat, head checking oraz wybuksowanie. Przedstawiono metodykę prowadzonych badań oraz wyniki analiz zarejestrowanych sygnałów dla warunków techniczno-eksploatacyjnych panujących na liniach kolejowych nr 213 Reda – Hel oraz nr 131 Chorzów Batory – Tczew. Wyniki badań drgań i hałasu dotyczą zarejestrowanych sygnałów dla odcinków toru z wadą oraz dla odcinków toru referencyjnego. Synteza wyników badań potwierdza zasadność rozwijania metody z wykorzystaniem sygnałów drganiowych do prowadzenia diagnostyki powierzchni tocznych szyn, jak również wskazuje na możliwość wykorzystania sygnałów wibroakustycznych do oceny innych elementów nawierzchni kolejowej.

  • Impact of Boundary Conditions on Acoustic Excitation of EntropyPerturbations in a Bounded Volume of Newtonian Gas
    • Anna Perelomova
    2019 Full text Archives of Acoustics

    Excitation of the entropy mode in the field of intense sound, that is, acoustic heating, is theoreticallyconsidered in this work. The dynamic equation for an excess density which specifies the entropy mode,has been obtained by means of the method of projections. It takes the form of the diffusion equation withan acoustic driving force which is quadratically nonlinear in the leading order. The diffusion coefficient isproportional to the thermal conduction, and the acoustic force is proportional to the total attenuation.Theoretical description of instantaneous heating allows to take into account aperiodic and impulsivesounds. Acoustic heating in a half-space and in a planar resonator is discussed. The aim of this studyis to evaluate acoustic heating and determine the contribution of thermal conduction and mechanicalviscosity in different boundary problems. The conclusions are drawn for the Dirichlet and Neumannboundary conditions. The instantaneous dynamic equation for variations in temperature, which specifiesthe entropy mode, is solved analytically for some types of acoustic exciters. The results show variationin temperature as a function of time and distance from the boundary for different boundary conditions.Keywords:nonlinear acoustics; acoustic heating in resonators; Burgers equation; first and second typeboundary conditions; acoustic heating in a half-space

  • Impact of Cyclist Facility Availability at Work on the Number of Bike Commuters
    • Romanika Okraszewska
    2019 Advances in Intelligent Systems and Computing

    The article describes the results of research designed to establish whether cycle provision can influence the number of employees commuting by bike. To that end, employee surveys were conducted in three IT companies in 2012 and 2016. The questionnaire asked about travel behaviour and what the staff thought about their company’s provision of cyclist facilities. Since 2012 each of the companies has moved its head office and the facilities for cyclists have improved. The studies from 2012 indicated a greater impact of an unseen level of organizational culture than that of artifacts such as facilities for cyclists at the company or its location relative to the system of city cycle paths. Results from 2016 indicate that when significant changes are made on the artifacts level the influence on the number of cyclists can be noticeable.

  • Impact of digital signal processing on FOC current feedback in high-speed PMSM drive
    • Leszek Jarzębowicz
    • Miroslav Gutten
    2019 Full text

    In applications where size and weight of the electric motor are among major design concerns, Permanent Magnet Synchronous Motors (PMSMs) with wide operational speed-range are commonly preferred. Due to limited inverter switching frequency, high-speed operation of a drive results in a low ratio between the switching frequency and the fundamental frequency of motor voltage. Such operating conditions have been recently identified as a source of errors in determining motor current feedback using the typical technique dedicated for microprocessor-based controllers. First, sampling the phase currents synchronously with the peaks of modulation carrier provides results of mean currents under an assumption of linear current changes in steady voltage intervals. This assumption is over-simplistic in high-speed drives. Second, transforming the phase currents into a rotating reference frame, required in Field Oriented Control (FOC), is carried out using discretized rotor angle. If rotor covers a substantial angular distance in the control cycle, such simplification distorts transformation results considered as mean values. This paper analyses the joint impact of both these oversimplifications on the errors of field-oriented current components derived in a microprocessor as a feedback to the control algorithm. The analysis was carried out for a high-speed PMSM drive operating at switching frequency of 5 kHz and maximal fundamental frequency of 350 Hz. Simulation results show that the considered oversimplifications lead to notable errors in digital processing of current feedback. The direct-axis current is affected by a notable offset, while the quadrature-axis current is supplemented with a high-frequency error component.

  • Impact of high temperature drying process on beech wood containing tension wood
    • Ivan Klement
    • Tatiana Vilkovská
    • Uhrín Miroslav
    • Jacek Barański
    • Aleksandra Konopka
    2019 Full text Open Engineering

    The technology of high temperature drying has a great inuence on dimensional and selected physical changes in tension wood. Article is focused on the measurement properties such as moisture content, color changes and longitudinal warping. The quality of beech wood is determined based on structure and properties of wood, frequency of defects in wood material. The tension wood is considered as an important wood defect causing negative alterations in solidwood quality and limits industrial application ofwood. The dierent values of longitudinalwarpingwhichwere measured after dryingwere higher in tensionwood than in normalwood. Impact of radial and tangential angle of growth rings is non-signicant factor.

  • Impact of polder flood plain of the Cisowska Struga on the transformation of flood waves between Gdynia and Rumia
    • Michał Szydłowski
    • Wojciech Szpakowski
    2019 Full text Acta Scientiarum Polonorum Formatio Circumiectus

    The paper presents the results of hydraulic calculations (numerical simulations), which were made to investigate the role of floodplain (polder) adjacent to the left bank of Cisowska Struga in Gdynia downstream Hutnicza St. in the process of retention and transformation of flood waves occurring in this river due to torrential rainfall. The paper also addressed the issue of the impact of potential changes in the development of the retention area under consideration for the flood risk in Rumia.

  • Impact of probability distribution on the uncertainty of resistance measurement
    • Stanisław Szczesny
    • Anna Golijanek-Jędrzejczyk
    • Dariusz Świsulski
    2019 Full text ITM Web of Conferences

    The paper presents studies on the influence of probability distributions on the expanded uncertainty of the resistance measurement. Choosing the correct probability distribution is very important to estimate of measurement uncertainty. The paper presents the results of analysis of the resistance measurement uncertainty using the technical method of resistance: 100 G. The analysis of the uncertainty measurement of resistance was carried out repeatedly, each time assuming a different probability distribution of measuring instruments (normal, quadratic, U and triangular distribution).The results of the research presented in the article show that the influence of the assumed probability distributions on the result of the measurement uncertainty analysis is significant and results discrepancies can reach up to 40%.

  • Impact of reclaimed asphalt pavement (RAP) on low-temperature properties of asphalt concrete
    • Mariusz Jaczewski
    • Bohdan Dołżycki
    • Jacek Alenowicz
    • Piotr Jaskuła
    2019 Full text Roads and Bridges - Drogi i Mosty

    Hot mix recycling is a practice which enables reusing materials from old asphalt pavements. Current Polish regulations allow usage of RAP only for binder and base courses, and its amount is limited. Asphalt mixtures with RAP material have to fulfil requirements stated for typical asphalt mixtures. The research presents low-temperature properties of twelve different asphalt concretes with RAP material, determined using three-point bending test. Mixtures differed in: type (for wearing, binder or base courses), content of RAP (from 0% up to 60%), quality of RAP material and application of rejuvenator. For all mixtures, RAP content strongly influences mechanical properties – critical strain and flexural strength. Their values decreased with an increase in the used amount of RAP. The greatest decrease was observed for wearing and binder courses. The changes were much smaller for base course mixtures, even with higher amounts of RAP.

  • Impact of slow breathing on the blood pressure and subarachnoid space width oscillations in humans
    • Magdalena Nuckowska
    • Marcin Gruszecki
    • Jacek Kot
    • Jacek Wolf
    • Wojciech Gumiński
    • Andrzej F. Frydrychowski
    • Jerzy Wtorek
    • Krzysztof Narkiewicz
    • Krzysztof Narkiewicz
    • Pawel Winklewski
    2019 Full text Scientific Reports

    The aim of the study was to assess cardiac and respiratory blood pressure (BP) and subarachnoid space (SAS) width oscillations during the resting state for slow and fast breathing and breathing against inspiratory resistance. Experiments were performed on a group of 20 healthy volunteers (8 males and 12 females; age 25.3 ± 7.9 years; BMI = 22.1 ± 3.2 kg/m2). BP and heart rate (HR) were measured using continuous finger-pulse photoplethysmography. SAS signals were recorded using an SAS monitor. Oxyhaemoglobin saturation (SaO2) and end-tidal CO2 (EtCO2) were measured using a medical monitoring system. Procedure 1 consisted of breathing spontaneously and at controlled rates of 6 breaths/minute and 6 breaths/minute with inspiratory resistance for 10 minutes. Procedure 2 consisted of breathing spontaneously and at controlled rates of 6, 12 and 18 breaths/minute for 5 minutes. Wavelet analysis with the Morlet mother wavelet was applied for delineation of BP and SAS signals cardiac and respiratory components. Slow breathing diminishes amplitude of cardiac BP and SAS oscillations. The overall increase in BP and SAS oscillations during slow breathing is driven by the respiratory component. Drop in cardiac component of BP amplitude evoked by slow-breathing may be perceived as a cardiovascular protective mechanism to avoid target organ damage. Further studies are warranted to assess long-term effects of slow breathing.

  • Impact of Tetrazolium Ionic Liquid Thermal Decomposition in Solvothermal Reaction on the Remarkable Photocatalytic Properties of TiO2 Particles
    • Marta Paszkiewicz-Gawron
    • Anna Gołąbiewska
    • Anna Pancielejko
    • Wojciech Lisowski
    • Julia Zwara
    • Monika Paszkiewicz
    • Adriana Zaleska-Medynska
    • Justyna Łuczak
    2019 Full text Nanomaterials

    Ionic liquids (ILs) could serve as a structuring agent, a solvent, or a source of dopant during solvothermal synthesis of semiconductors particles. To understand the role of IL during formation of TiO2 particles, it is necessary to study the stability of this IL in solvothermal synthesis conditions, as well as studying the surface properties of formed TiO2 particles. In view of this, the effect of the 2,3,5-triphenyltetrazolium chloride IL ([TPTZ][Cl]) thermal decomposition during the solvothermal reaction and IL content in the reaction system on photoactivity of TiO2 microparticles has been systematically investigated. The samples obtained by using [TPTZ][Cl] exhibited remarkable photocatalytic properties in phenol degradation reaction under visible light. HPLC analysis of the solvothermal reaction medium and X-ray photoelectron spectroscopy (XPS) analysis of TiO2 particles revealed that [TPTZ][Cl] was decomposed completely and was incorporated into the TiO2 lattice. Generally, increasing the reaction time (1, 4, 12, and 24 h) promoted the TiO2 microspheres formation, as well as raising the visible light-induced photocatalytic activity of the photocatalysts. Longer reaction time was also accompanied by an increase in the efficiency of 2,3,5-triphenyltetrazolium chloride decomposition. The properties of the photocatalysts were investigated by means of UV-VIS diffuse reflectance spectroscopy (DRS), BET surface area measurements, scanning electron microscopy (SEM), X-ray powder diffraction (XRD) analysis, and XPS.

  • Impact of the Artificial Strait in the Vistula Spit on the Hydrodynamics of the Vistula Lagoon (Baltic Sea)
    • Michał Szydłowski
    • Tomasz Kolerski
    • Piotr Zima
    2019 Full text Water

    In the Vistula Lagoon, storm surges are induced by variable sea levels in the Gulf of Gdańsk and wind action. The rising of the water level in the southern part of the basin, exceeding 1.0 m above mean sea level, can be dangerous for the lowland area of Żuławy Elbląskie, causing the inundation of the polders adjacent to the lagoon. One of the potential possibilities to limit the flood risk is to decrease the water level in the lagoon during strong storm surges by opening an artificial canal to join the lagoon with the Gulf of Gdańsk. The decision to build a new strait in the Vistula Spit was made in 2017. In order to analyze the impact of the artificial connection between the sea and the lagoon during periods of high water stages in the southern part the lagoon, mathematical modelling of the hydrodynamics of the Vistula Lagoon is required. This paper presents the shallow water equations (SWEs) model adapted to simulate storm surges driven by the wind and sea tides, and the numerical results obtained for the present (without the new strait) and future (with the new strait) configuration of the Vistula Lagoon.

  • IMPACT OF THE ORGANISATION OF MEGA SPORTING EVENTS ON SELECTED ELEMENTS OF THE TOURISM SECTOR
    • Krystian Zawadzki
    2019 Full text Polish Journal of Sport and Tourism

    Introduction. In the world-wide literature, there is no unanimity in the assessment of the impact of mega sporting events on the tourism sector. Therefore, the main purpose of this study was to quantify the impact of mega sporting events on changes in tourist inflow and the amount of expenditure incurred by visitors. Material and methods. In this study, an ex-post analysis of many different categories of mega sporting events was carried out in the context of their impact on selected aspects of the tourism sector in host countries. The study examined events organised in the years 1996-2014 classified into one of four categories: the Summer Olympic Games (SOG), the Winter Olympic Games (WOG), the Football World Cup (FIFA), and the European Football Championship (UEFA). The approach adopted made it possible to analyse the impact of sporting events on the tourism sector over 15 years. Data on both the inflow of tourists and the expenditure generated by them were taken from a single source – reports of the United Nations World Tourism Organization (UNWTO). Results. The results obtained are characterised by ambiguity, although the study identified the categories of sporting events and the sporting event phase in which clearly positive or negative effects on the tourism sector could be observed. Conclusions. The difficulty in confirming unambiguously positive, tangible effects on the tourism sector resulting from the organisation of mega sporting events makes it problematic to justify the commitment of large expenditure to preparing and conducting these events. It is necessary to look for other, intangible benefits related to the organisation of these events. It also seems appropriate to continue the research undertaken in the future on the basis of data disaggregated at the regional level.

  • Implementation of Addition and Subtraction Operations in Multiple Precision Arithmetic
    • Kamil Rudnicki
    • Tomasz Stefański
    2019

    In this paper, we present a digital circuit of arithmetic unit implementing addition and subtraction operations in multiple-precision arithmetic (MPA). This adder-subtractor unit is a part of MPA coprocessor supporting and offloading the central processing unit (CPU) in computations requiring precision higher than 32/64 bits. Although addition and subtraction operations of two n-digit numbers require O(n) operations, the efficient implementation of these operations can provide valuable time-savings for the MPA coprocessor. Furthermore, MPA numbers are usually stored with the use of the sign-magnitude representation which is not so straightforward for addition/subtraction implementation as the two's complement representation. Our adder-subtractor unit is implemented using the very high speed integrated circuit hardware description language (VHDL) and benchmarked on Xilinx Artix-7 FPGA. The developed digital circuit of the MPA adder-subtractor works with integer numbers of precision varying in the range between 64 bits and 32 kbits with the limb size set to 64 bits. It can currently work with the clock frequency exceeding 450 MHz. For the developed implementation, the addition of two k-limb numbers takes 33+k clock cycles. Hence, the developed coprocessor is 1.7 times faster than a single core of modern i7 processor for precision set to 32704 bits.

  • Implementation of control system and tracking objects in a Quadcopter
    • Siva Ariram
    • Juha Roning
    • Zdzisław Kowalczuk
    2019 Full text

    In this paper, we implement a quadcopter assembly with control and navigation module. The project also includes the design of the control panel for the operator which consists of a set of the micro-controller and the glove equipped with sensors and buttons. The panel has a touch screen which displays current parameters such as vehicle status, including information about orientation and geographical coordinates. The concept of quadcopter control is based on the movement of the operator hand. In addition, we have included the object detection for detecting the objects from the quadcopter view of point. To detect an object, we need to have some idea of where the object may be and how the image is divided into segments. It creates a kind of chicken and egg problem, where we must recognize the shape (and class) of the object knowing its location and recognize the location of the object knowing its shape. Some visual characteristics such as clothing and the human face, they can be part of the same subject, but it is difficult to recognize this without recognizing the object first.

  • Implementing Smart Virtual Product Development (SVPD) to Support Product Manufacturing
    • Muhammad Ahmed
    • Cesar Sanin
    • Edward Szczerbicki
    2019

    This paper illustrates the concept of providing the manufacturing knowledge during early stages of product life cycle to experts working on product development. The aim of this research is to enable a more collaborative product development environment by using Smart Virtual Product Development (SVPD) system, which is powered by Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA). It enhances the industrial product development process by storing, using and sharing previous manufacturing experience and knowledge. This knowledge is stored in form of formal decisional events after being collected from the set of similar products having some common functions and features. The proposed system uses a collective, team-like knowledge developed by product designers, manufactures, and metrologists. Implementing this system in the process of product development enables the small and medium enterprises (SMEs) to take proper decisions at appropriate time by reducing mistakes at an early stages of product development.

  • Importance of Specific Heat Characterization when Reporting New Superconductors: An Example of Superconductivity in LiGa2Rh
    • Elizabeth M. Carnicom
    • Weiwei Xie
    • Zoe Yang
    • Karolina Górnicka
    • Tai Kong
    • Tomasz Klimczuk
    • Robert J. Cava
    2019 CHEMISTRY OF MATERIALS

    We show that the full-Heusler compound LiGa2Rh is a superconductor with Tc = 2.4 K. The new superconductor was found as a result of an intuition-based extension of a database search for superconductors that looked for the presence of peaks in the electronic band structure near the Fermi energy. The measurement of the entropy loss during the transition from the nonsuperconducting to the superconducting state, a straightforward measurement rarely presented in reports of “new” superconducting materials, played a critical role in identifying and isolating the superconducting compound. This study presents a particularly good example of how specific heat measurements are important for the identification and isolation of a new superconductor, since much more frequently reported resistive and magnetic susceptibility characterizations are often not enough to confirm the identification of a new superconducting material.

  • Improved Empirical Coefficients for Estimating Water Vapor Weighted Mean Temperature over Europe for GNSS Applications
    • Zofia Baldysz
    • Grzegorz Nykiel
    2019 Full text Remote Sensing

    Development of the so-called global navigation satellite system (GNSS) meteorology is based on the possibility of determining a precipitable water vapor (PWV) from a GNSS zenith wet delay (ZWD). Conversion of ZWD to the PWV requires application of water vapor weighted mean temperature (Tm) measurements, which can be done using a surface temperature (Ts) and its linear dependency to the Tm. In this study we analyzed up to 24 years (1994–2018) of data from 49 radio-sounding (RS) stations over Europe to determine reliable coefficients of the Tm-Ts relationship. Their accuracy was verified using 109 RS stations. The analysis showed that for most of the stations, there are visible differences between coefficients estimated for the time of day and night. Consequently, the ETm4 model containing coefficients determined four times a day is presented. For hours other than the primary synoptic hours, linear interpolation was used. However, since this approach was not enough in some cases, we applied the dependence of Tm-Ts coefficients on the time of day using a polynomial (ETmPoly model). This resulted in accuracy at the level of 2.8 ± 0.3 K. We also conducted an analysis of the impact of this model on the PWV GNSS. Analysis showed that differences in PWV reached 0.8 mm compared to other commonly used models.

  • Improved energy management technique in pipe-embedded wall heating/cooling system in residential buildings
    • Marek Krzaczek
    • Jarosław Florczuk
    • Andrzej Tejchman-Konarzewski
    2019 APPLIED ENERGY

    Effective and environmentally responsive techniques of energy management in residential buildings are desirable for the resulting reduction of energy costs and consumption. In this paper, an improved and efficient technique of energy management in pipe-embedded wall heating/cooling systems, called the Thermal Barrier, is described. Specifically, the Thermal Barrier is a technique focused on the management and control of heat supply into and heat extraction from external walls containing embedded pipes. The installed pipe-embedded wall heating/cooling system is fully controlled by a special fuzzy logic program that synchronizes the heat supply/extraction with variable heat loads. The main operation rule of the Thermal Barrier is to keep changes of the wall internal energy close to zero for the given reference temperature of a pseudo-surface created by an embedded pipe system of the wall heat exchanger. Comprehensive field measurement results associated with an example Thermal Barrier System installed in a residential two-story house are presented. These measurements confirmed the high-efficiency of the Thermal Barrier and its ability to use low-grade heat sources and sinks to effectively control an indoor climate. The supply water temperature was very low (25.3 °C) in the winter and very high (20.5 °C) in the summer. Daily variations of the indoor air temperature did not exceed 0.8 °C throughout the year. During the summer, the Thermal Barrier System operated in cooling-mode only from a low-grade renewable heat sink. The flexibility of the Thermal Barrier also allows for using heat sources/sinks different from those in the test house.