2015 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2015

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Effect of temperature and ionic strength on volumetric and acoustic properties of solutions of urea alkil derivatives in aqueous NaCl
- Joanna Krakowiak
- Jarosław Wawer
2015 JOURNAL OF CHEMICAL THERMODYNAMICS
The present work was undertaken to study volumetric and acoustic properties for diluted solutions of tetramethylurea in pure water and for urea, n-propylurea, n-butylurea and tetramethylurea in 0.5 or 1 moldm3 aqueous solutions of sodium chloride. This paper presents measured values of densities and sound velocities at T = (288.15, 298.15 and 308.15) K. From these data the apparent molar volumes, , adiabatic compressibilities, S, and apparent molar adiabatic compressions, , were obtained. The values of apparent molar volumes for infinite dilution and limited apparent adiabatic compressions were calculated from extrapolation of the concentration dependence. Further, the corresponding transfer data as well as hydration number of urea and its derivatives in the studied systems were estimated. The obtained parameters are discussed in terms of various solute-solvent and solute-cosolute interactions.
Effect of underwater wet welding conditions on the diffusible hydrogen content in deposited metal
- Dariusz Fydrych
- Aleksandra Świerczyńska
- Grzegorz Rogalski
2015 METALLURGIA ITALIANA
In the study mercury displacement method was used for determination of diffusible hydrogen amount in deposited metal obtained during underwater wet welding with covered electrodes in laboratory conditions according to a two-level full factorial design for three factors. The factors and their levels were chosen among conditions and parameters of welding in accordance with the results of own preliminary studies. A statistical analysis succeeded in establishing an equations to correlate conditions of wet welding with diffusible hydrogen content in deposited metal. A comparison of the influence of studied variables with the results of preliminary studies was also made. In order to minimize diffusible hydrogen level, underwater wet welding with covered electrodes is to be carried out with negative polarity as well as the minimum value of welding current. Results of measurements of the diffusible hydrogen amount in deposited metal were in the range from 39.54 to 61.86 ml/100g. These results imply that it is possible to obtain in wet welding conditions level of diffusible hydrogen content characteristic for welding in the air.
EFFECT OF WORKING FLUID SELECTION ON THERMAL PERFORMANCE OF HEAT EXCHANGER FILLED BY THE POROUS MATERIAL
- Paweł Szymański
2015 Full text Journal of Polish CIMEEAC
Thermal management of electronics semiconductor technologies that are located i.e. in a novel marine power plants or computer server rooms become very important issue for designers of such systems. Motivation and need for research in development of novel cooling strategies for modern electronics is of paramount importance. Heat exchangers filled by the porous material are a novel research topic in current heat pipe science. The design of such heat exchangers is rather complex with many things to consider. In this paper the focused is the get knowledge about who to select the working fluid to be used.
Effective Short -term Forecasting of Wind Farms Power
- Elżbieta Bogalecka
- Tomasz Rubanowicz
2015 Full text Acta Energetica
Forecasting a specific wind farm's generation capacity within a 24 hour perpective requires both a reliable forecast of wind, as well as supporting tools. This tool is a dedicated model of wind farm power. This model should include not only general rules of wind to mechanical energy conversion, but also the farm's specific features. This paper present analytical, statistical, and neuron models of wind farm power. The study is based on data from a real wind farm. Most attention is paid to the neuron models, due to a neuron network's capacity to restore farm-specific details. The research aim to answer the headline question: whether and to what extent a wind farm's power can be forecast short-term.
Effectiveness of the robust PSS design
- Zbigniew Lubośny
- Krzysztof Dobrzyński
- Jacek Klucznik
2015
The paper discusses optimal PSS of synchronous generator synthesis. The optimal controller is an Hinf controller, what means that minimises Hinf norm of transfer function between the exogenous signals such as reference inputs and disturbances, and the error signals which are to be minimised to meet the control objective. The dynamic properties of the plant are shaped by choosing appropriate weighting function applied to the plant output and input signals. Question appears: does such type of PSS design lead to effective PSS design which can be used in real power system?
Effects of Store Brand Perceived Risk on Buyers’ Behavior – Four Decades of Research Overview = Wpływ postrzeganego ryzyka związanego z markami własnymi na zachowania nabywców – przegląd czterech dekad badań
- Przemysław Łukasik
- Bruno Schivinski
2015 Full text Annales Universitatis Mariae Curie-Skłodowska, Sectio H Oeconomia
Abstract. The aim of this paper is to present the concept of store brand perceived risk and the most important studies on its measurement that were being conducted for 40 years. For this purpose, an extensive literature review is introduced. Some aspects of the risk constructs and major effects of store brand perceived risk are emphasized. This paper provides key directions to brand managers regarding store brand assortment.
Efficiency of gas detection algorithms using fluctuation enhanced sensing
- Łukasz Lentka
- Janusz Smulko
- Radu Ionescu
2015
Efficiency of various gas detection algorithms by applying fluctuation enhanced sensing method was discussed. We have analyzed resistance noise observed in resistive WO3- nanowires gas sensing layers. Power spectral densities of the recorded noise were used as the input data vectors for two algorithms: the principal component analysis (PCA) and the support vector machine (SVM). The data were used to determine gas concentration by regression methods. Additionally, the SVM algorithm used the slope of 1/f noise estimated for consecutive low frequency bands only to reduce the volume of computation by limiting the input data vector size. The results show that the SVM method gives the best results when the input vector is a power spectral density.
Efficient algorithm for blinking LED detection dedicated to embedded systems equipped with high performance cameras
- Michał Tarkowski
- Przemysław Woźnica
- Łukasz Kulas
2015
This paper presents the concept and implementation of an efficient algorithm for detection of blinking LED or similar signal sources. Algorithm is designed for embedded devices equipped with high performance cameras being a part of an indoor positioning embedded system. An algorithm to be implemented in such a system should be efficient in terms of computational power what is hard to be achieved when large amount of data from camera devices have to be processed. Together with increasing number of MPs (Megapixels) of camera sensor the possibility of accurate detection of LED signal source also increases, especially when the distance between the source and a camera is long. High number of FPS (Frames Per Second) is necessary if the time period for optical signal transmission have to be short. This condition is important for high detection and identification speed and also makes the whole system less sensitive to tracked object motion and changes in the scene. The cost of these advantages is larger amount of data to be processed by a computation unit what can cause a problem, when the system needs to work in close to real time conditions. In the paper the proposed efficient algorithm for blinking LED detection is described and experimental results are presented as the evaluation of algorithm performance.
Efficient knowledge-based optimization of expensive computational models using adaptive response correction
- Sławomir Kozieł
- Leifsson Leifur
2015 Journal of Computational Science
Computer simulation has become an indispensable tool in engineering design as they allow an accurate evaluation of the system performance. This is critical in order to carry out the design process in a reliable manner without costly prototyping and physical measurements. However, high-fidelity computer simulations are computationally expensive. This turns to be a fundamental bottleneck when it comes to design automation using numerical optimization techniques. In particular, direct optimization of simulation models, typically, requires a large number of model evaluations, which may be impractical or even infeasible in a reasonable timeframe. Possibly the most promising approach to alleviate this difficulty is surrogate-based optimization (SBO), where direct optimization of expensive models is replaced by an iterative enhancement and re-optimization of fast surrogate models. While a large variety of surrogate modeling and optimization are available, the methods exploiting the so-called physics-based surrogates seem to be the most efficient ones because the knowledge about the system of interest embedded in the underlying (often simulation-based) low-fidelity model ensures good generalization of the surrogate and a rapid convergence of the SBO algorithm. In this paper, we review a specific technique of this class, that is, the adaptive response correction (ARC). We discuss the formulation of the method, its limitations and generalizations, as well as illustrate its application for solving problems in various areas, including microwave engineering, antenna design, and aerodynamic shape optimization.
Efficient Multi-Fidelity Design Optimization of Microwave Filters Using Adjoint Sensitivity
- Adrian Bekasiewicz
- Sławomir Kozieł
2015 INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING
A simple and robust algorithm for computationally efficient design optimiza-tion of microwave filters is presented. Our approach exploits a trust-region (TR)-based algorithm that utilizes linear approximation of the filter response obtained using adjoint sensitivity. The algorithm is sequentially executed on a family of electromagnetic (EM)-simulated models of different fidelities, starting from a coarse-discretization one, and ending at the original, high-fidelity filter model to be optimized. Switching between the models is determined using suitably defined convergence criteria. This arrangement allows for sub-stantial cost reduction of the initial stages of the optimization process without compromising the accuracy and resolution of the final design. The performance of our technique is illus-trated through the design of a fifth-order waveguide filter and a coupled iris waveguide fil-ter. We also demonstrate that the multi-fidelity approach allows for considerable computational savings compared to TR-based optimization of the high-fidelity EM model (also utilizing adjoint sensitivity).
Efficient quadrature for fast oscillating integralof paraxial optics
- Sergei Kshevetskii
- Paweł Wojda
2015 Full text Mathematica Applicanda (Matematyka Stosowana)
The study concerns the determination of quadrature for the integral solutionof the paraxial wave equation. The difficulty in computation of the integral isassociated with the rapid change of the integrand phase. The developed quadraturetakes into account the fast oscillating character of the integrand. The presentedmethod is an alternative to the commonly used methods based on the use of theFourier transform. The determination of the quadrature is discussed on the exampleof the integral arisen in the theory of propagation and focusing on hard X-rayswaves. Due to the generality of the presented quadrature, it may also be applied toissues related to standard optics and acoustics.
Efficient signal processing in spectroscopic optical coherence tomography
- Maciej Kraszewski
- Michał Trojanowski
- Marcin Strąkowski
2015
Spectroscopic optical coherence tomography (SOCT) is an extension of a standard OCT technique, which allows to obtain depth-resolved, spectroscopic information on the examined sample. It can be used as a source of additional contrast in OCT images e.g. by encoding certain features of the light spectrum into the hue of the image pixels. However, SOCT require computation of time-frequency distributions of each OCT A-scan, what is a very time consuming procedure. This is particularly important in a real-time OCT imaging. Here, we present a new approach to SOCT signal processing that allows for nearly tenfold reduction of a required computation time. The presented approach is based on a recursive analysis of OCT scan in time-domain without necessity of computing neither short-time Fourier transform or any other time-frequency distribution.
EHV transmission lines wires location on line operation issues - case studies
- Jacek Klucznik
- Zbigniew Lubośny
- Krzysztof Dobrzyński
- Stanisław Czapp
2015
Transmission lines towers construction affects the line parameters and influences on its operation in the future. Misguided design of the tower can lead to serious problems such as overvoltages, electric arc extinction difficulties, voltage asymmetry, resonance phenomena or increasing of magnetic field near the line. The paper points out those threats on example of 400 kV double circuit overhead transmission line with shunt reactors. The paper discuses the impact of circuits orientation of the transmission line, phase wires arrangement and line transpositions on above problems. The study includes steady state analyses and transient analyses (EMT simulations).
Ekoinżynieria w zintegrowanym odwadnianiu i stabilizacji osadów ściekowych w systemach trzcinowych
- Hanna Obarska-Pempkowiak
- Katarzyna Kołecka
- Katarzyna Buchholtz
- Magdalena Gajewska
2015 Przemysł Chemiczny
W artykule przedstawiono zasady budowy i pracy systemów trzcinowych do zintegrowanego odwadniana i stabilizacji osadów ściekowych oraz ogólne zasady dotyczące projektowania oraz eksploatacji systemów, a także określono ekonomiczne i środowiskowe aspekty wynikające ze stosowania tej technologii na podstawie najnowszych doniesień literatury oraz doświadczeń własnych. Eksploatacja odpowiednio zaprojektowanych systemów trzcinowych polega na okresowym nawadnianiu osadami o małej zawartości suchej masy wynoszącej 0,5– 1,0%. Czas zatrzymania osadów w celu odwodnienia i stabilizacji wynosi 10–15 lat. Osady ulegają przekształceniu w substancję humusową, która po sprawdzeniu właściwości mikrobiologicznych i fizyczno- chemicznych może być wykorzystywana rolniczo.
Ekologiczne pianki poliuretanowe otrzymane z surowców odnawianych
- Paulina Kosmela
- Michał Gągol
- Krzysztof Formela
- Kamila Gosz
- Lukasz Piszczyk
2015
Przedmiotem pracy była charakterystyka ekologicznych, sztywnych pianek poliuretanowych otrzymanych z biopoliolu uzyskanego w wyniku upłynniania biomasy celulozowej frakcją glicerynową. Sztywne pianki otrzymano metodą jednoetapową z układu dwukomponentowego przy stosunku grup NCO do OH wynoszącym 2:1. Udział biopoliolu w stosunku do zawartości komercyjnego poliolu wynosił odpowiednio 25, 50, 75 oraz 100 % mas. Otrzymane układy scharakteryzowano pod kątem właściwości fizyko-mechanicznych (gęstość pozorna, wytrzymałość na ściskanie) oraz mikrostruktury przy użyciu mikroskopii optycznej. Na podstawie otrzymanych wyników określono wpływ biopoliolu na właściwości użytkowe sztywnych pianek poliuretanowych.
Ekonomiczna analiza motywacji polskiego sędziego i czynniki wpływające na jego decyzje związane z wyborem zawodu i efektywnością
- Przemysław Banasik
2015 Full text Journal of Public Governance
W artykule przedstawiono motywy, którymi kieruje się polski sędzia przy wyborze zawodu, a także jakie czynniki w ramach wykonywanego przez niego zawodu jest skłonny brać pod uwagę aby zwiększyć swoją efektywność. W pracy posłużono się badaniem ilościowym oraz jakościowym.
Ekonomiczne i środowiskowe aspekty skoncentrowanej fotowoltaiki
- Jolanta Fieducik
- Jan Godlewski
2015 Full text Przegląd Elektrotechniczny
W artykule przeanalizowano możliwość wykorzystania promieniowania słonecznego do wytwarzania energii elektrycznej, ze szczególnym uwzględnieniem roli skoncentrowanego promieniowania słonecznego. Skoncentrowana fotowoltaika (CPV), przy użyciu wielowarstwowych ogniw fotowoltaicznych, pozwala na obniżenie kosztów instalacji oraz kosztów wytwarzania energii elektrycznej. Rozwój nowych technologii wytwarzania energii elektrycznej z użyciem skupionego promieniowania słonecznego pozwala także na wykorzystanie korzystających z wysokiej temperatury do generacji energii elektrycznej na różnej drodze. W artykule przeanalizowano także aspekt ekonomiczny i środowiskowy, wynikający z wprowadzania nowych technologii do wytwarzania energii elektrycznej z promieniowania słonecznego.
Ekspertyza : Mapa rozwoju dyscypliny Elektrotechnika : Systemy Elektroenergetyczne
- Zbigniew Szczerba
- Maciej Pawlik
- Jacek Marecki
- Bolesław Zaporowski
- Marian Sobierajski
- Kazimierz Wilkosz
- Józef Lorenc
- Waldemar Szpyra
- Zbigniew Lubośny
- Jacek Wańkowicz
2015 Full text Przegląd Elektrotechniczny
W publikacji przedstawiono trendy rozwojowe dyscypliny elektrotechnika opracowanej przez Komitet Elektrotechniki PAN.
Ekspertyza dla Rady Dzielnicy Gdańsk Orunia -Św. Wojciech-Lipce - w sprawie wniosku do sporządzanego Studium Uwarunkowań i Kierunków Zagospodarowania Przestrzennego Miasta Gdańska
- Gabriela Maria Rembarz
2015
Ekspertyza posłużyła jako podstawa do sporządzenia Uchwały Nr IX/25/2015 z dnia 09.12.2015 Rady Dzielnicy Gdańsk Orunia -Św. Wojciech-Lipce - w sprawie wniosku do sporządzanego Studium Uwarunkowań i Kierunków Zagospodarowania Przestrzennego Miasta Gdańska
Ekspertyza dla Rady Dzielnicy Gdańsk Osowa - w sprawie wniosku do Studium uwarunkowań i kierunków zagospodarowania przestrzennego Miasta Gdańska
- Justyna Martyniuk-Pęczek
2015
Ekspertyza posłużyła jako podstawa do sporządzenia Uchwały Rad Dzielnic do Studium nr XI/24/2015 z dnia 9 grudnia 2015 w sprawie wniosków do Studium uwarunkowań i kierunków zagospodarowania przestrzennego Miasta Gdańska