2014 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2014

Pokaż wszystkie

Failure Analysis of footbridge made of composite materials
- Jacek Chróścielewski
- Ireneusz Kreja
- Agnieszka Sabik
- Bartosz Sobczyk
- Wojciech Witkowski
2014
Finite element method analysis of a pedestrian footbridge made of sandwich material is presented. The internal structure of the material is modelled as a structural shell assuming the Equivalent Single Layer approach (ESL). Two FEM commercial codes are employed. The response of the structure is studied in order to determine the load level that activates Hashin and Tsai-Wu failure criteria. Some practical aspects of designing footbridges are also addressed.
Falowniki wielopoziomowe 6kV/1MVA do napędów o regulowanej prędkości obrotowej i układów kompensacji mocy biernej
- Marek Adamowicz
- Zbigniew Krzemiński
2014 Automatyka Elektryka Zakłócenia
W referacie przedstawiono konstrukcję modułowego tranzystorowego przekształtnika napięcia 6 kV/1 MVA nowej generacji o dwukierunkowym przepływie energii pomiędzy siecią średniego napięcia (SN) a silnikiem indukcyjnym klatkowym, przeznaczonego do napędów SN o regulowanej prędkości obrotowej. Istota rozwiązania przedstawionego przekształtnika zawiera się w zastosowaniu trójstopniowej struktury. Stopnień wejściowy oraz stopień wyjściowy są realizowane za pomocą wielopoziomowych przekształtników napięcia: wielopoziomowego prostownika aktywnego oraz wielopoziomowego falownika maszynowego. Stopień pośredni realizowany za pomocą izolowanych przetwornic dc-dc z transformatorami wysokiej częstotliwości (> 5 kHz) zapewnia izolację galwaniczną pomiędzy wejściem i wyjściem. Przy zasilaniu z sieci przemysłowej SN omawiany przekształtnik nie wymaga stosowania transformatora sieciowego dla eliminacji negatywnego wpływu pojemności pasożytniczych i napięć składowej zerowej. Odpowiednio zaprojektowany prostownik aktywny przekształtnika może służyć do kompensacji mocy biernej na szynach rozdzielnicy SN. Zasadę działania przekształtnika omówiono na przykładzie zrealizowanego przekształtnika 3,3 kV/0,6 MVA pracującego w napędzie pompy w odwiercie ropy naftowej.
Fast clutter cancellation for noise radars via waveform design
- Michał Meller
2014 IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
Canceling clutter is an important, but very expensive part of signal processing in noise radars. It is shown that considerable improvements can be made to a simple least squares canceler if minor constraints are imposed onto noise waveform. Using a combination of FPGA and CPU, the proposed scheme is capable of canceling both stationary clutter and moving targets in real-time, even for high sampling rates.
Fast Low-fidelity Wing Aerodynamics Model for Surrogate-Based Shape Optimization
- Leifur Leifsson
- Sławomir Kozieł
- Adrian Bekasiewicz
2014 Pełny tekst Procedia Computer Science
Variable-fidelity optimization (VFO) can be efficient in terms of the computational cost when compared with traditional approaches, such as gradient-based methods with adjoint sensitivity information. In variable-fidelity methods, the directoptimization of the expensive high-fidelity model is replaced by iterative re-optimization of a physics-based surrogate model, which is constructed from a corrected low-fidelity model. The success of VFO is dependent on the reliability and accuracy of the low-fidelity model. In this paper, we present a way to develop a fast and reliable low-fidelity model suitable for aerodynamic shape of transonic wings. The low-fidelity model is component based and accounts for the zero-lift drag, induced drag, and wavedrag. The induced drag can be calculated by a proper method, such lifting line theory or a panel method. The zero-lift drag and the wave drag can be calculated by two-dimensional flowmodel and strip theory. Sweep effects are accounted for by simple sweep theory. The approach is illustrated by a numerical example where the induced drag is calculated by a vortex lattice method, and the zero-lift drag and wave drag are calculated by MSES (a viscous-inviscid method). The low-fidelity model is roughly 320 times faster than a high-fidelity computational fluid dynamics models which solvesthe Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras turbulence model. The responses of the high- and low-fidelity models compare favorably and, most importantly, show the same trends with respect to changes in the operational conditions (Mach number, angle of attack) and the geometry (the airfoil shapes).
Fast Multi-Objective Antenna Design Through Variable-Fidelity EM Simulations
- Sławomir Kozieł
- Adrian Bekasiewicz
- Włodzimierz Zieniutycz
2014
A technique for fast multi-objective antenna optimization is introduced. A kriging interpolation surrogate constructed from sampled coarse-mesh EM simulations is utilized by multi-objective evolutionary algorithm (MOEA) to obtain the initial Pareto front approximation. The surrogate is defined in a subset of the original design space, determined by means of independently optimized individual objectives. Response correction techniques are subsequently used to refine the designs selected from the initial Pareto set. Our approach is demonstrated using a planar UWB dipole antenna.
Fatigue and burnout in police officers: the mediating role of emotions
- Beata Basińska
- Izabela Wiciak
- Anna Maria Dåderman
2014 POLICING-AN INTERNATIONAL JOURNAL OF POLICE STRATEGIES & MANAGEMENT
Purpose – The policing profession is associated with psychosocial hazard. Fatigue and burnout often affect police officers, and may impair the functioning of the organization and public safety. The relationship between fatigue and burnout may be modified by job-related emotions. While negative emotions have been extensively studied, the role of positive emotions at work is relatively less known. Additionally, there is insufficient knowledge about the role of the intensity of emotions. The purpose of this paper is to examine the role of job-related emotions in the relationship between fatigue and burnout in police officers. Design/methodology/approach – In all, 169 police officers (26 women) completed a test battery that assessed acute fatigue, burnout (Oldenburg Burnout Inventory: exhaustion and disengagement), and emotions (Job-related Affective Well-being Scale). Findings – Acute fatigue was associated more strongly with exhaustion than with disengagement. Low-arousal negative emotions partially mediated the relationship between fatigue and exhaustion. High-arousal positive and negative emotions were partial mediators between fatigue and disengagement experienced by police officers. Research limitations/implications – The results show that high-arousal emotions were associated with changes in work motivation, while low-arousal negative emotions reduced energetic ability to work. Originality/value – This paper enhances understanding of burnout among police officers and the mediating role of emotions. The patterns of the relationships between fatigue, burnout and emotions are discussed in the context of the conservation of resources theory and the tripartite model of anxiety and depression.
FE analysis of size effects in reinforced concrete beams without shear reinforcement based on stochastic elasto-plasticity with non-local softening.
- Ewelina Korol
- Andrzej Tejchman-Konarzewski
- Z. Mróz
2014 FINITE ELEMENTS IN ANALYSIS AND DESIGN
W artykule przedstawiono wyniki analizy MES dotyczącej deterministycznego i statystycznego efektu skali w żelbetowych belkach bez zbrojenia na ścinanie. W analizie zastosowano prawo sprężysto-plastyczne z nielokalnym osłabieniem. Wyniki analizy porównano z doświadczeniami i modelem skali Bazanta.
Fianl report on carrying out tasks within the project Best Agers Lighthouses - strategic age management for SME in the Baltic Sea Region.
- Krzysztof Zięba
2014
The report presents the origin of the project, as well as its characteristics and aims. Project partners are workpackages are described and main project results are listed. the report is concluded with the part dedicated to dissemination measures carried out within the project
Filozofia codzienności a wyzwania współczesności na przykładzie badań uczennic szkół gimnazjalnych w wybranych gminach województwa pomorskiego
- Paweł Bykowski
2014
W artykule dokonano próby przedstawienia wyrażonych przez uczennice szkół gimnazjalnych z terenu województwa pomorskiego ocen i opinii dotyczących charakterystycznych procesów, jakie zachodzą w otaczającej rzeczywistości.
Finite-element analysis of a base-isolated multi-storey steel building under seismic motions
- Tomasz Falborski
- Robert Jankowski
2014
Numerical simulation of the seismic behaviour of a multi-storey steel building, both fixed-base and base-isolated, under the 1940 El Centro earthquake was performed in this paper. The analyzed 4-storey building was decoupled from the shaking ground with the Polymeric Bearings, which can be considered a proposal of a new seismic isolation system. It consists of rectangular-shaped blocks made of a specially prepared flexible polymeric material whose chemical composition includes certain additives so as to improve its damping potential. The basic mechanical properties of this material have been already determined in experimental studies and the results have been presented in previous publications. Moreover, shaking table experimental study, using the prototype of the Polymeric Bearings supporting a 1.20 m high single-storey and a 2.30 m high two-storey steel structure models, was also performed and the results have proven the effectiveness of this base isolation system in suppressing structural vibrations during dynamic. The 5-parameter Mooney-Rivlin material was adopted to simulate the behaviour of seismic isolation bearings. This hyperelastic model provided the best fit with the previously obtained experimental results.
Firm-Level Internationalisation from the Theoretical Perspective: Knowledge-based Approach
- Nelly Daszkiewicz
2014
The objective of the paper is to present the role of knowledge in internationalisation process of the firm as well as the selected theoretical proposals which assume that the role of knowledge in international expansion of firms is crucial. The article first presents the selected but best known, the oldest internationalisation paradigms. Then it shows the direction of development of theoretical perspectives.
Fitting the mobile device characteristics to the user's hearing preferences
- Kuba Łopatka
- Piotr Suchomski
- Andrzej Ciarkowski
- Piotr Odya
- Andrzej Czyżewski
2014
A method for fitting the mobile computer audio characteristics to the user's hearing preferences is proposed. The process consists of two stages: calibration and dynamics processing. During the calibration phase the user performs a loudness scaling test giving their response regarding the perceived loudness. The dynamics processing made on above basis sets the loudness to the most comfortable level. The processing accounts both for the user's hearing preferences (or possible deficiencies) and for the playback characteristics of the device. The solution is implemented as a standalone PC calibration application and as an APO object installed in the system's audio driver.
Five-phase induction motor drive with sine-wave filter
- Paweł Stec
- Jarosław Guziński
- Patrick Strankowski
- Atif Iqbal
- Ahmad Anad Abduallah
- Haitham Abu-Rub
2014
The paper presents closed loop ac drive with 5 phase induction motor operating with voltage source inverter and sine wave filter. The motor supply voltages and currents have sinusoidal shape. For well known adjustable electric drives the field oriented control method with flux and speed co ntrol can be applied. In the presence of output filter both control and estimation algorithms should be modified due to sine wave filter installation. The major advantage of the drive with speed observer is an operation without motor speed sensor based on inverter currents and voltage embedded sensors. In this paper sensorless operation of a five phase induction motor drive with inverter output filter is accomplished. The validation of the drive operation was proved by simulation and experiments. The test bench was developed with prototype of 5 phase 4.3 kW induction motor and inverter with DSP control and sine wave filter is designed and built.
Flow of liquid in flat gaps of the satellite motor working mechanism
- Paweł Śliwiński
2014 Pełny tekst Polish Maritime Research
The article describes the methodology and results of investigations of the flow of oil and HFA-E emulsion in flat gaps of the working mechanism of a satellite motor. The flow of liquid in those gaps is turbulent and not fully developed. The article presents two methods of modelling this flow. Method I makes use of the Darcy-Weisbach formula, while Method II bases on the assumption that in the variable-length gaps the flow is turbulent in the area where the length is the smallest and laminar where the length is the largest. Consequently, the flow in such gaps can be modelled as the sum of laminar and turbulent flows. The results obtained in the experiment have made the basis for calculating relevant coefficients and assessing the proportion of turbulence in the flow modelled using both methods.
Flow structure, heat transfer and scaling analysis in the case of thermo-magnetic convection in a differentially heated cylindrical enclosure
- Elżbieta Fornalik-Wajs
- Piotr Filar
- Jan Wajs
- A. Roszko
- L. Pleskacz
- H. Ozoe
2014 Pełny tekst Journal of Physics : Conference Series
The experimental, numerical and scaling analysis in the case of thermo-magnetic convection in a thermosyphon-like enclosure filled with a paramagnetic fluid is presented. Visualization of temperature field together with the numerical simulation gave an information about the flow structure, which indicated “finger-like” structures of hot and cold streams advecting each other. Their number depended on the Rayleigh number and also on the magnetic induction. In the basis of thermal measurements the average Nusselt number was determined for various strength of magnetic field and in presented configuration increasing magnetic field caused increase in the Nusselt number. With the assumptions of two dimensional flow and the constant fluid properties, in the studied temperature range, the scaling analysis led to the Nusselt number correlation in dependence on the thermo-magnetic Rayleigh number. Very good agreement between the experimental results and scaling equation was observed.
Fluctuation enhanced gas sensing using UV irradiated Au-nanoparticle-decorated WO3-nanowire films
- Maciej Trawka
- Janusz Smulko
- Lech Hasse
- Claes G. Granqvist
- Radu Ionescu
- Fatima E. Annanouch
- Eduard Llobet
- Laszlo B. Kish
2014
WO3 nanowires (WO3-NWs) decorated with gold nanoparticles (AuNPs) were utilized in resistive gas sensor devices to detect ethanol by use of fluctuation enhanced sensing (FES). The experimental system records both DC resistance and fluctuations of the sensing film. Our data verify that the sensitivity and selectivity of the gas sensor are improved by applying FES when the sensor is stimulated with a combination of UV light and heating. We conclude that UV light can produce improved gas sensing at low operating temperatures for the investigated AuNP-decorated WO3-NWs films.
Fluorescent analogs of trypsin inhibitor SFTI-1 isolated from sunflower seeds-synthesis and applications
- Adam Lesner
- Natalia Karna
- Mateusz Psurski
- Anna Łęgowska
- Magdalena Wysocka
- Katarzyna Guzow
- Adam Sieradzan
- Marcin Sieńczyk
- Piotr Trzonkowski
- Pikuła Marek
- Maciej Zieliński
- Kosikowska Paulina
- Rałał Łukajtis
- Łęgowska Monika
- Dawid Dębowski
- Wiesław Wiczk
- Krzysztof Rolka
- Rafał Łukajtis
2014 BIOPOLYMERS
This article describes the synthesis and enzymatic study of newly synthesized analogs of trypsin inhibitors SFTI-1 that were fluorescent labeled on their N-terminal amino groups. Two fluorescent derivatives of benzoxazole (3-[2-(4-diphenylaminophenyl) benzoxazol-5-yl]-L-alanine[(4NPh(2)) Ph] Box-Ala and 3-[2-(2', 4', 5'-trimethoxyphenyl) benzoxazol-5-yl]-l-alanine-[2,4,5-(OMe)3Ph] Box-Ala) were used as efficient fluorescent labels. The compounds obtained preserved their inhibitory activity and were efficient inhibitors of bovine trypsin or chymotrypsin. Nevertheless, their association inhibition constants were one or two orders of magnitude lower than those determined for unlabeled monocyclic SFTI-1 or [Phe(5)] SFTI-1, respectively. The conjugates obtained were found to be proteolytically stable in the presence of cognate enzymes. Applying such fluorescent peptides, we were able to investigate enzyme-inhibitor complex formation using fluorescent techniques. We found that such compounds were rapidly internalized by the fibroblast or cancer cells with no cytotoxic effects. (C) 2013 Wiley Periodicals, Inc.
Food analysis using artificial senses.
- Magdalena Śliwińska
- Paulina Wiśniewska
- Tomasz Dymerski
- Jacek Namieśnik
- Waldemar Wardencki
2014 JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
Nowadays, consumers are paying great attention to the characteristics of food such as smell, taste, and appearance. This motivates scientists to imitate human senses using devices known as electronic senses. These include electronic noses, electronic tongues, and computer vision. Thanks to the utilization of various sensors and methods of signal analysis, artiﬁcial senses are widely applied in food analysis for process monitoring and determining the quality and authenticity of foods. This paper summarizes achievements in the ﬁeld of artiﬁcial senses. It includes a brief history of these systems, descriptions of most commonly used sensors (conductometric, potentiometric, amperometic/voltammetric, impedimetric, colorimetric, piezoelectric), data analysis methods (for example, artiﬁcial neural network (ANN), principal component analysis (PCA), model CIE L*a*b*), and application of artiﬁcial senses to food analysis, in particular quality control, authenticity and falsiﬁcation assessment, and monitoring of production processes.
"Food Oxidants and Antioxidants" Book review
- Izabela Sinkiewicz
2014 Polish Journal of Food and Nutrition Sciences
The book is the 14th title in the CRC series Chemical and Functional Properties of Food Components, edited since 2001 by Zdzisław E. Sikorski. The editor of the book, a professor in the University of Łódź and member of the Polish Academy of Sciences, is an internationally recognized authority in biochemistry and biophysics of reactive oxygen species. In Poland Grzegorz Bartosz has a reputation as the author of his most interesting book The Second Face of Oxygen (Druga twarz tlenu) published by the science publisher PWN in 1995 and in 2013 (second edition). The book has been prepared by 40 contributors from Australia, Denmark, Germany, Italy, Lithuania, Poland, Slovakia, Spain, and USA, specialized in various aspects of the broad fi eld of oxidants and antioxidants – concentration of these compounds in foods, measuring of their activity, mechanisms of interactions, factors affecting the rate of these reactions, effects on the sensory properties of food products, as well as their biological role and mode of action in the human organism when delivered in the diet.
Foreign visitors from Visegrad countries with regard to road safety in Poland
- Dagmara Jankowska
- Justyna Wacowska-Ślęzak
- Joanna Żukowska
2014 Pełny tekst Periodica Polytechnica transportation Engineering
In the paper the authors present road safety situation in the Polish regions mostly visited by Czech, Slovakian and Hungarian tourists. These regions include Mazowieckie, Dolnoslaskie, Slaskie and Malopolskie voivodeships. After description of the regions and main touristic destinations for foreigners from Visegrad countries, a detailed road safety analysis performed for the period 2007-2012 is given. The paper ends with conclusions in which the authors underline the main road safety problems and recommend the steps that should be undertaken in order to improve the road safety level.