2016 - Repozytorium publikacji - Politechnika Gdańska

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Evaluation of apparent Young׳s modulus of the composite polymer layers used as sliding surfaces in hydrodynamic thrust bearings
- Michał Wodtke
- Michał Wasilczuk
2016 Pełny tekst TRIBOLOGY INTERNATIONAL
Hydrodynamic bearings with a polymer sliding layer are able to operate in severe conditions, mainly due to favorable properties of the polymers. The goal of this research was to evaluate apparent Young׳s modulus of two types of the polymer composite layers used for sliding surfaces in hydrodynamic bearings, as a function of temperature. The Young׳s modulus was evaluated on the basis of compression tests carried out on samples obtained from thrust bearing pads. Measurements were accompanied by additional FEM calculations, reproducing the experiment. The results presented in the paper prove that apparent Young׳s moduli of the studied types of the composite layers depend significantly on temperature and their values differ from existing information in available data on polymers.
Evaluation of applicability of classic methods of a fault loop impedance measurement to circuits with residual current devices
- Stanisław Czapp
- Kornel Borowski
2016 Pełny tekst Acta Energetica
Measurement of fault loop impedance in low voltage grids and systems is in most cases performed to verify the effectiveness of protection against electric shock by automatic disconnection of supply. For the sake of measurement accuracy, it is advisable to perform it using large current. Unfortunately, in circuits with residual current devices which are very widely used nowadays, a large measurement current may trigger those devices unnecessarily. The study presents results of an investigation of residual current devices behaviour during measurements of fault loop impedance performed with selected measuring devices. The tests have been performed on circuits with residual current devices with a rated residual operating current IΔn = 30 mA, of AC and A type. Based on the performed tests and analyses, a method for measurement of fault loop impedance which does not unnecessarily trigger residual current devices has been proposed.
Evaluation of candidate reference material obtained from selenium - enriched sprouts for the purpose of selenium speciation analysis
- Małgorzata Bodnar
- Piotr Konieczka
2016 LWT-FOOD SCIENCE AND TECHNOLOGY
Selenium is an essential element in animals and humans. Diet supplementation with selenium-rich vegetables has better chemoprotective effect than Se (IV) and SeMet. The production of selenium-enriched vegetables requires a preliminary stage in soil preparation, which may subsequently pose a risk of soil contamination. It seems that the sprouting of seeds under controlled conditions would be a good solution for delivering SeMetSeCys to the human organism. The certified reference material is necessary in order to follow the safety rules during the application of selenium-enriched foods in cancer prevention. Such reference material will contribute to the development of research methods for determining specific species of selenium. Therefore, we undertook an effort to produce the appropriate reference material for Se speciation analysis by using Se-enriched sprouts. Six types of sprouts, mainly from the family Brassicaceae, were selected for the study. The sprouts grown in both media accumulate significant amounts of selenium. However, only the plants cultivated in the medium containing Na2SeO3 are capable of converting inorganic selenium into SeMetSeCys and SeMet. The sprouts of broccoli and white mustard grown in the medium containing 10 mg/L Na2SeO3 were selected as potential candidates for certified reference materials.
Evaluation of organic coatings condition with AFM-based method
- Michał Szociński
2016 Surface Innovations
The paper presents an atomic force microscopy (AFM)-based approach to evaluation of local protective properties of organic coatings. Apart from topography, it provides local ac and dc characteristics of examined coating. The method consists in application of ac voltage perturbation signal between conductive AFM tip and coated metal substrate. The resulting current is used to determine local impedance characteristics. Both impedance imaging and impedance spectroscopy modes are available. The measurements are performed in contact AFM regime either for continuous scanning of the tip over the surface or for stationary positioning of the tip over the area of interest. Application of dc bias voltage between the AFM tip and the coated metal substrate makes it possible to verify coating continuity and to identify the potential sites with through-the-coating defects, which penetrate the coating down to the metal substrate. Description of the fundamentals of the technique is supported with selected examples of research results. The obtained topographical images, impedance images, local impedance spectra and dc current maps are correlated as well as supplementary with respect to each other showing that the proposed approach is capable of providing additional information about local behaviour and durability of organic coatings.
Evaluation of Pavement Temperatures in Poland During Winter Conditions
- Marek Pszczoła
- Józef Judycki
- Dawid Ryś
2016 Transportation Research Procedia
The paper presents the analysis of pavement temperatures from meteorological stations located at the Polish national roads during the impact of low winter temperatures. Presented issue is particularly important in view of the problem of low-temperature cracks that occur in the asphalt pavement under the influence of low temperatures. For each location of meteorological station there were analysed measurements of the temperature on the road pavement surface, at depth of 5 cm and 30 cm in the pavement structure and air temperature 20 cm above the pavement surface. The analysis of the data included determination of minimum surface temperatures, duration of low temperatures, distributions of temperatures at the depth of pavement structure and the rate of cooling of the pavement surface. The number of temperature transitions for a specified level of low temperatures: 0 degrees C, -5 degrees C, -10 degrees C, -15 degrees C and -20 degrees C were also determined. It was found that the longest uninterrupted period of surface temperature hold below -20 degrees C is 18 hours, but below -15 degrees C is already 85 hours. On the basis of the distributions of temperature at the depth of pavement structure it was found that the recorded values of the minimum temperature of up to -25 degrees C on the surface of the asphalt pavement, the temperature at a depth of 5 cm, is higher by about 2-4 degrees C than the surface temperature, while at depth of 30 cm it is already higher by about 20 degrees C than the surface temperature. Another important factor affecting the performance of asphalt pavement and in particular the resistance to low-temperature cracking is the cooling rate. With increase of cooling rate during severe winter conditions the probability of low temperature cracking increase. It was found that the cooling rate of the asphalt pavement surface is up to 3 degrees C/h.
Evaluation of respiration rate and pattern using a portable thermal camera
- Jacek Rumiński
2016
The goal of this paper was to analyze the accuracy of the proposed method for the evaluation of respiration rate and respiration rhythm patterns (e.g. inspiration slope) using the portable and mobile thermal camera module that could be a part of smart glasses. Parameters were analyzed for 12 volunteers in two experiments, when subjects speak and do not speak. The pressure, chest belt was used as a reference measurement method. Data analysis showed that respiration rate and some respiration-related parameters could be accurately measured with the used methodology.
Evaluation of the content of inorganic anions in tree saps
- Maciej Bilek
- Kinga Stawarczyk
- Piotr Kuniar
- Marcin Olszewski
- Katarzyna Kędziora
- Ewa Cielik
2016 Pełny tekst Journal of Elementology
Tree saps were once commonly used in the countries of Northern, Central and Eastern Europe. Although once almost forgotten, their popularity has been growing recently as part of an interest in organic food and traditional medicine. Tree saps, tapped mainly from birch and maple trees, are drunk both fresh and fermented or are used as raw material for the production of food products, e.g. syrups. The aim of this study was to determine the content of inorganic anions in tree saps, as this parameter is often associated with toxicity of plant products. We measured the content of chlorides, nitrates and sulphates in the saps of six tree species with high pressure ion chromatography with the conductometric detection method. We detected the presence of chlorides, nitrates and sulphates in the studied tree saps. The highest concentration of nitrates was in the saps tapped from Norway maple (65.578 mg dm-3) and boxelder (108.313 mg dm-3). On the other hand, the highest concentration of sulphates was detected in the white willow tree saps (112.512 and 35.389 mg dm-3), while the one of chlorides, in the hornbeam tree sap (47.257 mg dm-3) and the Norway maple tree sap (41.143 mg dm-3). The detected content of chlorides, sulphates and nitrates in the tree saps under study does not reach toxic levels. Therefore we conclude that tree saps do not pose any health threat to consumers regarding their content of inorganic ions. Additionally, we observed a high intra- and interspecies variability in the concentration of inorganic anions in saps. This observation should be taken into account while designing any quality monitoring protocol regarding tree saps.
Evaluation of the suitability of electronic nose based on fast GC for distinguishing between the plum spirits of different geographical origins
- Magdalena Śliwińska
- Paulina Wiśniewska
- Tomasz Dymerski
- Waldemar Wardencki
- Jacek Namieśnik
2016 Pełny tekst EUROPEAN FOOD RESEARCH AND TECHNOLOGY
Plum spirits are obtained exclusively via the alcoholic fermentation and distillation of meaty plums or must composed of plums, with or without stones. The European countries such as Poland, the Slovak Republic, the Czech Republic, Bulgaria and Romania are the leading producers of this alcoholic beverage. Information about the authentication of plum spirits produced in different countries can be found in the published literature. Gas chromatography, sensory analysis and spectroscopic techniques were the most frequently used research tools in those studies. So far, there were no available published reports about the suitability of an electronic nose based on fast GC for analyzing plum spirits. The volatile fractions of six samples of four different origins (Poland, Czech Republic, the Slovakia and Romania) with 40 % alcoholic content were analyzed using electronic nose based on fast GC (Heracles II). Four data analysis methods were used, namely principal component analysis, discriminant function analysis, soft independent modeling of class analogies and statistical quality control. In this work, for discrimination of results was used Euclidean distance between each sample, standard deviation and coefficient of variation. Conducted research was aimed at the evaluation of the suitability of an electronic nose based on fast GC for distinguishment between the volatile profiles of plum spirits of different geographical origins. These studies are the foundation for further work on discrimination of samples of plum spirits produced within a greater number of geographical regions. All the applied chemometric methods turned out to be effective.
Evaluation of Vehicle Routing Problem Algorithms for Transport Logistics Using Dedicated GIS System
- Krzysztof Bruniecki
- Andrzej Chybicki
- Marek Moszyński
- Mateusz Bonecki
2016
The development and research related to optimization of fleet management is of high interest among many industrial and scientific entities related to logistics and transport. Optimal distribution of transportation resources leads to significant cost reduction. In this context, scientific research related to so called Vehicle Routing Problem (VRP) which relies on determining the shortest transport routes for a strictly limited number of means of transport, whose aim is to handle a set of customers located in different geographic locations while maintaining defined restrictions is of high interest. In the paper, the process of design and implementation of the dedicated ICT system for optimization of fleet management using VRP class solving algorithms is presented. The theoretical background, the technical description of the proposed system and the evaluation of proposed theoretical approaches is described.
Evolution of electrohydrodynamic flow of sduspended particles in a needle-to-plate negative DC corona discharge in air
- Jerzy Mizeraczyk
- Artur Berendt
- Janusz Podliński
- Anna Niewulis
2016 International Journal of Plasma Environmental Science & Technology
Corona discharges are used for collecting dust in electrostatic precipitators (ESPs). The dust collection is mainlyrealized by the electric forces which move the ionized dust particles to the collecting electrodes. However, the presence of coronadischarge in the space between the charging and collecting electrodes in ESPs causes also the so-called ionic wind which set the gasmolecules and dust particles in motion. As a consequence, a secondary electrohydrodynamic (EHD) flow is formed, which affectsthe primary flow of the dust-polluted gas and the collection of the dust particles.In this communication we present images and velocity field maps and showing the temporal and spatial evolution of the EHD flowof the air and suspended dust particles in a needle-to-plate DC corona discharge arrangement, simulating an ESP. The measurementswere mainly focused on the time period just after the corona discharge onset. The experimental apparatus for our study of EHDflow consisted of a needle-to-plate electrode ESP, high voltage power supply and standard 2D Particle Image Velocimetry (PIV)equipment.The needle-to-plate electrode arrangement consisted of a needle (1 mm in diameter) electrode made of a stainless-steel, the endof which had a tapered profile with the tip having a radius of curvature of 75μm. The interelectrode distance was 25 mm. Negativevoltage of 8 kV was supplied to the needle electrode. An acrylic box, with the needle-to-plate electrode arrangement inside, wasfilled with air seeded with dust particles (incense smoke).The flow and velocity field (PIV) images, recorded just after the corona discharge onset (in intervals from tens to hundreds ms)illustrate the temporal and spatial evolution of the EHD flow (air and the suspended particles) between the needle-to-plate electrodearrangement. They clearly show the formation of a ball-like structure of the particle flow at the needle tip and its evolution intoa mushroom-like object moving with an average velocity of about 2.5 m/s towards the collecting electrode. This movement initiatesa flow of the seeded air from the needle-tip vicinity into the space between electrodes. Then the EHD flow develops into two veryregular vortices, rotating in opposite directions, and eventually the regular vortices disappear.
Evolving neural network as a decision support system — Controller for a game of “2048” case study
- Arkadiusz Kwasigroch
- Michał Grochowski
2016
The paper proposes an approach to designing the neuro-genetic self-learning decision support system. The system is based on neural networks being adaptively learned by evolutionary mechanism, forming an evolved neural network. Presented learning algorithm enables for a selection of the neural network structure by establishing or removing of connections between the neurons, and then for a finding the beast suited values of the network weights and biases. The algorithm was validated on problem of learning to play the game of “2048”. The game has in fact very simple rules however it is very important to have a proper control strategy in order to gain high score. Moreover, existence of random factors makes it more difficult. The evolved neural controller is trying itself to discover and to learn the best strategy leading to the highest score. In the result, the controller has obtained a game score at a level similar to medium advanced human player. It is interesting that strategies developed by the controller are similar to the strategies that are applied by experienced human players. The paper provides an overview and an analysis of the impact of the main system factors on obtained results. Finally, the most important findings are indicated and future work is specified.
Ewaluacja jakości kształcenia w kadecji 2012-2016, podsumowanie i wnioski
- Alicja Konczakowska
2016 Dzień Jakości PG
przedstawiono działalność Uczelnianej Komisji ds. Jakości Kształcenia w czasie kadencji 2012-2016
Ewolucja rachunkowości chińskiej na tle czynników kulturowych determinujących jej rozwój
- Celina Bójczuk
2016 Pełny tekst Przestrzeń Ekonomia Społeczeństwo
Rachunkowość jest złożonym systemem, którego kształt uwarunkowany jest wieloma czynnikami, także czynnikami środowiska, w którym realizuje swoje zadania. Wśród tych czynników ważne miejsce zajmuje kultura, właściwa dla danego kraju, która odbija swe piętno na celach i sposobie funkcjonowania systemu pomiaru i ujawnień rachunkowych. Dobitnym przykładem występowania korelacji pomiędzy kształtem rachunkowości a czynnikami kultury są Chiny, które mogą się poszczycić długą i barwną historią rachunkowości. W całym okresie ewolucji chińskiej rachunkowości ukazuje się jej podporządkowanie wyzwaniom stawianym przed nią przez środowisko jej funkcjonowania, kształtowane m.in. przez konfucjanizm, buddyzm czy feng shui. Celem niniejszego opracowania jest próba prezentacji czynników wpływających na kształt rachunkowości Kraju Środka oraz prezentacja na ich tle zmian w rachunkowości chińskiej na przestrzeni wieków.
Examination method of the effect of the incidence angle of laser beam on distance measurement accuracy to surfaces with different colour and roughness
- Karol Daliga
- Zygmunt Kurałowicz
2016 Pełny tekst Boletim de Ciencias Geodesicas
Interest in the influence of the incidence angle of a laser beam to distance measurements can be seen in many areas of science and technology: geodesy, glaciology, archaeology, machine automation, and others. This paper presents results of measurements of the effect of the incidence angle of a laser beam to distance measurements to the surfaces of different colour and roughness by Topcon's electro-optical total station with an accuracy of 3 mm. Measurement method and the method of elimination of test stand errors are presented. The results of measurements have been analysed and the influence of selected factors (surface colour and roughness, lack of instrument rectification) on the distance measurement have been discussed. It is also shown the critical incidence angle above which it can be impossible to measure distances to reflective foil with tested total station
Examples of Original Descriptive Geometry Task Items
- Bożena Kotarska-Lewandowska
2016 Pełny tekst The Journal of Polish Society for Geometry and Engineering Graphics
The paper presents several descriptive geometry drawing tasks and a comprehensive approach to their evaluation. The results as the task profile include the most important features and enable interpretation of the tasks in the educational system.
Excavation induced cast iron pipeline failure – a numerical study
- Krzysztof Szarf
- Rafał Ossowski
2016 Pełny tekst Inżynieria Morska i Geotechnika
Numerical study on impact of an unsecured excavation on an underground pipeline. Analysis focused on investigation of pipeline displacement generated by soil movement caused by excavation and heavy traffic. Numerical calculations and soil parameter sensitivity analysis based on Finite Element Method. Some comparisons of results with real-life failure cases.
Excitation energy transfer in partly ordered polymer films differing in donor and acceptor transition moments orientation
- Anna Synak
- Piotr Bojarski
- Michał Sadownik
- Leszek Kułak
- Ignacy Gryczyński
- Beata Grobelna
- Simeonika Rangełowa-Jankowska
- Dawid Jankowski
- Aleksander Kubicki
2016 OPTICAL MATERIALS
Based on spectroscopic measurements selected properties of nonradiative Förster energy transport are studied in uniaxially stretched polyvinyl alcohol thin films for three systems differing in donor and acceptor transition moments orientation relative to the axis of stretching. In particular, donor – acceptor emission anisotropy spectra yield completely different regularities for these systems in uniaxially stretched films, whereas they are similar in unstretched films. In particular it is shown that acceptor fluorescence can be either strongly polarized after nonradiative energy transfer in stretched films or depolarized depending on the angular distribution of acceptor transition moments in the matrix. Donor and acceptor emission anisotropy decays exhibit similar regularities to those of steady-state measurements. The obtained results are analyzed with the help of Monte Carlo simulations.
Executing Multiple Simulations in the MERPSYS Environment
- Paweł Rościszewski
2016
The chapter investigates the steps necessary to perform a simulation instance in the MERPSYS environment and discusses potential limitations in case when vast numbers of simulations are required. An extended architecture is proposed which includes a JMS-based simulation queue and multiple distributed simulators, overcoming the potential bottlenecks. The chapter introduces also methods for preparing suites of multiple simulations for parallel execution. Additionally, potential use cases of the framework are discussed, including a concept of parallel application optimizer.
EXHAUST GAS TEMPERATURE MEASUREMENTS IN DIAGNOSTICS OF TURBOCHARGED MARINE INTERNAL COMBUSTION ENGINES PART II DYNAMIC MEASUREMENTS
- Zbigniew Korczewski
2016 Pełny tekst Polish Maritime Research
The second part of the article describes the technology of marine engine diagnostics making use of dynamic measurements of the exhaust gas temperature. Little-known achievements of Prof. S. Rutkowski of the Naval College in Gdynia (now: Polish Naval Academy) in this area are presented. A novel approach is proposed which consists in the use of the measured exhaust gas temperature dynamics for qualitative and quantitative assessment of the enthalpy flux of successive pressure pulses of the exhaust gas supplying the marine engine turbocompressor. General design assumptions are presented for the measuring and diagnostic system which makes use of a sheathed thermocouple installed in the engine exhaust gas manifold. The corrected thermal inertia of the thermocouple enables to reproduce a real time- history of exhaust gas temperature changes.
Expedited constrained multi-objective aerodynamic shape optimization by means of physics-based surrogates
- Sławomir Kozieł
- Yonatan Tesfahunegn
- Leifur Leifsson
2016 Pełny tekst APPLIED MATHEMATICAL MODELLING
In the paper, computationally efficient constrained multi-objective design optimization of transonic airfoil profiles is considered. Our methodology focuses on fixed-lift design aimed at finding the best possible trade-offs between the two objectives: minimization of the drag coefficient and maximization of the pitching moment. The algorithm presented here exploits the surrogate-based optimization principle, variable-fidelity computational fluid dynamics (CFD) models, as well as auxiliary data-driven surrogates (here, using Kriging). In order to permit computationally feasible construction of the Kriging models, initial design space reduction is also utilized. The design process has three major stages: (i) identification of the extreme points of the Pareto front through single-objective optimization (one objective at a time), (ii) construction of the Kriging model and initial Pareto front generation using multi-objective evolutionary algorithm (MOEA), and (iii) Pareto front refinement using response correction techniques and local response surface approximation (RSA) models. For the sake of computational efficiency, stages (i) and (ii) are realized at the level of coarse-discretization CFD model. The RSA models are also utilized to predict the angle of attack necessary to achieve the target lift coefficient, which considerably reduces the CFD simulation effort involved in the design process. Two design case studies are considered involving B-spline-parameterized airfoil shapes with 8 and 12 design variables. The 10-element Pareto front representations are obtained at the cost corresponding to just over two hundred of high-fidelity CFD model evaluations. This cost is not only considerably lower (up to two orders of magnitude) than the cost of direct high-fidelity model optimization using metaheuristics but, more importantly, renders multi-objective optimization of aerodynamic components computationally tractable even at the level of accurate CFD models.