2013 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2013

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Experimental investigation of dryout of SES36, R134a, R123 and ethanol in vertical small diameter tubes
- Dariusz Mikielewicz
- Jan Wajs
- Michał Gliński
- Abdul-Baset R.s. Zrooga
2013 EXPERIMENTAL THERMAL AND FLUID SCIENCE
W publikacji przedstawiono wyniki badań eksperymentalnych kryzysu wrzenia typu dryout podczas wrzenia w przepływie czterech czynników (SES36, R134a, R123, alkohol etylowy) w kanałach o średnicy wewnętrznej 1.15 mm i 2.3 mm. Badania przeprowadzono w szerokim zakresie zmian stopnia suchości pary (0.65-1), gęstości strumienia masy (40-900 kg/(m2s)) i gęstości strumienia ciepła (20-220 kW/m2). W badaniach wykorzystano technikę termowizyjną do lokalizacji miejsca wysychania filmu cieczowego na ściance kanału. W oparciu o zgromadzoną bazę danych zaproponowano korelację opisującą krytyczny strumień ciepła dla minikanałów.
Experimental investigation of the PEM fuel cells performance for automotive and stationary applications
- Janusz Cieśliński
- Bartosz Dawidowicz
- Tomasz Kaczmarczyk
2013
The aim of the study was to provide dynamic characteristics of the PEM fuel cell system consisted of Nexa modules, provide steady-state characteristics of the for different values of air excess ratio and steady-state characteristics for different stack temperatures and given load.
Experimental Investigations of Fracture Process Using DIC in Plain and Reinforced Concrete Beams under Bending
- Łukasz Skarżyński
- Andrzej Tejchman-Konarzewski
2013 STRAIN
The fracture behaviour of concrete and reinforced concrete beams under quasi-static three-point bending was comprehensively investigated with experiments at laboratory scale. The eight various concrete mixes were tested. The influence of the shape, volume and size of aggregate particles and reinforcement on concrete fracture under bending was studied. Displacements on the surface of concrete beams were measured by means of the digital image correlation (DIC) technique. Attention was paid to the formation of a localized zone and its characteristics. In order to avoid the effect of the search patch size and the cut-off value at displacement and strain profiles, a consistent method was proposed to determine uniformly and accurately the width of a localized zone. Measured surface displacements from DIC were fitted by the error function ERF, whereas surface strains calculated from displacements were fitted by the usual normal distribution (Gauss) function. The width of a localized zone preceding a macro-crack grew strongly with increasing maximum aggregate size and slightly with diminishing aggregate volume. It did not depend on the aggregate roughness and reinforcement presence.
Experimental investigations of size effect in reinforced concrete beams failing by shear
- Ewelina Korol
- Andrzej Tejchman-Konarzewski
2013 ENGINEERING STRUCTURES
W artykule omówiono wyniki doświadczalne efektu skali w zbrojonych betonowych belkach niszczących się przez ścinanie. Doświadczenia wykonano dla belek o różnych wymiarach ze zbrojeniem stalowym i bazaltowym. Podczas doświadczeń pomierzono siłę oraz szerokości lokalizacji i rys. Wyniki porównano z modelem skali wg Bazanta.
Experimental ORC micro-power plant for CHP application Part A: power plant arrangement
- Krzysztof Kosowski
- Jarosław Mikielewicz
- Eugeniusz Ihnatowicz
- Dariusz Kardaś
- Dariusz Mikielewicz
- Zbigniew Kozanecki
- Marian Piwowarski
- Robert Stępień
- Wojciech Włodarski
- Maciej Kaniecki
2013
The co-generative micro-power plant with the HFE7100 applied as a working medium was designed and built for experimental investigations. The heat output of the plant was assumed equal to 20 kW, while the electric output amounted to about 3kW. Examples of the results of the preliminary experimental research on a boiler, heat exchangers, a pump and a turbine-generator set are presented and analysed.
Experimental ORC micro-power plant for CHP application Part B: Radial and Multi-stage axial turbines
- Krzysztof Kosowski
- Zbigniew Kozanecki
- Marian Piwowarski
- Robert Stępień
- Wojciech Włodarski
- Łukasz Hirt
2013
The co-generative micro-power plant with the HFE7100 applied as a working medium was designed and built for experimental investigations. Special attention is paid to a micro-turbine which was built and tested in two variants: a radial turbine and an axial turbine. A concept of a radial turbine with 2 centripetal and 2 centrifugal stages is shown. This prototype was equipped with an aerostatic gas bearing and, alternatively, with a foil bearing. An axial multi-stage turbine with partial admission of all the stages is described in detail and the results of experimental investigations and numerical calculations are presented, followed by a discussion and conclusions. The results showed that, for example, remarkable flow separation zones appeared in the nozzle flow channels placed at the edge of the admission segments. The modifications of these channels reduced the undesirable effect. All the stages were equipped with movable blade shields for reducing windage losses. The effect of the angular position of the shields in the succeeding stages was investigated numerically and experimentally. The details, including the strength of particular turbine elements, are discussed and the dynamic behaviour of the turbogenerator rotor system is also examined. The proposed axial micro-turbine has a relatively high efficiency and the rotor speed of about 8000rpm which seems to be a low value compared with the other considered variants.
Experimental research on helical coil biomass boiler with oil as a heating fluid
- Tomasz Turzyński
- Dariusz Kardaś
2013 Transactions of the Institute of Fluid-Flow Machinery
This paper presents an experimental research of helical coil biomass boiler with thermal oil heating agent. Heat exchanger consists of two coaxial helical coils swept by the flue gases. The burner is a single vertical retort connected to the fuel tank (wooden pellets). The boiler is a part of micro-power plant in which the heat from the boiler is exchanged with low-boiling HFE7100 to produce steam for a custom steam turbine. The electrical output from the power plant is designed to be approximately 2kW. Experiments have been conducted without the ORC plant section – the heat from the thermal oil is being exchanged with a glycol-water solution and dumped to the atmosphere in air cooler. The mass flow-rate of glycol solution was fixed during the experiments. The measurement and acquisition system has been designed to be able to register and automatically store all characteristic parameters such as temperatures of thermal oil on inlet/outlet from the boiler, temperatures and flow rate of flue gases inside the exchanger and stack, flow rates of air and oil. The composition of flue gases has been measured independently by a separate analyzer. Acquired data was used to create complete characteristics of the device, verify the design and recognize several adjustments to be implemented in the next prototype.
Experimental study on ultrasonic monitoring of splitting failure in reinforced concrete
- Magdalena Rucka
- Krzysztof Wilde
2013 Pełny tekst JOURNAL OF NONDESTRUCTIVE EVALUATION
This paper investigates inspection of reinforced concrete elements sensitive to the splitting failure. The behaviour of a reinforced concrete specimen subjected to a tensile stress is considered. The damage detection procedure is based on the ultrasonic wave propagation technique. The piezoelectric transducers are located on both ends of the specimen and the measurements are taken periodically during the incrementally increased loading. The features of measured signals in time and frequency domains as well as wavelet transforms before and after the splitting failure are studied. The experimental results show that proposed method can be used for monitoring of damage evolution in concrete elements. The method makes possible detection of the moment just before the splitting failure occurs.
Exploring the factor structure and the validity of the abbreviated Basic and Earning Self-Esteem Scales
- Anna Maria Dåderman
- Beata Basińska
2013 Nordic Psychology
The original longer versions (Forsman & Johnson, 1996) and abbreviated versions of the Basic and Earning Self-Esteem Scales have been used in clinical and non-clinical settings, but little is known about the factor structure and the validity of these scales in their abbreviated forms. The original longer versions of the scales comprise several dimensions, but both abbreviated versions of the scales have been interpreted as if they were 1D. The abbreviated versions of the Basic and Earning Self-Esteem Scales have been translated into Polish from Swedish and administered to 175 students (103 female; mean age ¼ 22.7 years, SD ¼ 3.3 years) studying management at the Gdansk University of Technology. The aim of the present study was to investigate the factor structure and the validity of the abbreviated versions of the scales. We were also interested in the differences between women and men. Exploratory factor analyses identified one dimension of the Basic Self-Esteem Scale, compatible with Rosenberg’s et al. (1995) and Rogers’ (1951) concepts. We identified two components (High Ambition and Others’ Appraisal) of the Earning Self-Esteem Scale, similar to the original longer version. Convergent and discriminant validity proved to be theoretically solid. The abbreviated versions of the Basic and Earning Self-Esteem Scales are appended. Further research on these scales involving other groups is needed, as is further development of these self-esteem scales for adults. Evidence of the derived factors’ internal consistency and of the convergent and discriminant validity suggests that the factor structure and the reliability of the abbreviated versions of psychological tools need to be investigated.
Exploring the role of social networks among entrepreneurial Polish immigrants
- Marzena Starnawska
2013
The paper reports on the explanatory case study among seven Polish enterprising migrants from Aberdeen Scotland. The aim of the paper is to examine role of social support structure and social networks for enterprising Poles. It also attempts to extend of Waldinger et al (2000) ethnic business development model in the context of entrepreneurial strategies taken from by immigrants from their country of origin, claiming that transition economy has significantly shaped enterprising behaviours of many generations.
Extending Service Selection Algorithms with Interoperability Analysis
- Paweł Kaczmarek
2013 Communications in Computer and Information Science
Application development by integration of existing, atomic services reduces development cost and time by extensive reuse of service components. In Service Oriented Architecture, there exist alternative versions of services supplying the same functionality but differing in Quality of Service (QoS) attributes, which enables developers to select services with optimal QoS. Existing algorithms of service selection focus on the formal model of the composite service refraining from interoperability issues that may affect the integration process. In this paper, the author proposes a methodology that extends existing service selection algorithms by introducing additional constraints and processing rules representing interoperability. Two computational models are considered: the graph-based model and the combinatorial model. The extensions enable a straightforward application of a wide range of existing algorithms. The paper also describes a system that implements chosen service selection algorithms together with appropriate extensions for interoperability analysis.
Extracellular proteolytic activity of Deinococcus geothermalis
- Olga Pietrow-Tobiszewska
- Anna Panek
- Józef Synowiecki
2013 AFRICAN JOURNAL OF BIOTECHNOLOGY
Production of extracellular protease by extremophilic bacteria Deinococcus geothermalis cultivated in liquid media containing 0.1% (w/v) of peptone K, 0.1% yeast extract and 0.2% marine salt reached a maximum in 14 h of the cell growth at 45°C and pH 8.0. The enzyme was purified by a two-step procedure using fractionation by a graded ammonium sulphate precipitation technique and gel filtration on Sephadex G-100 column. Protease from D. geothermalis with a molecular mass of 24 kDa was active at 60°C and pH 9.0. The enzyme solution was stable for 1 h at 60°C and displayed about 60% of the initial activity after 1 h incubation at pH values 5.0 and 11. The phenylmethanesulfonyl fluoride (PMSF) at 1 mM concentration decreased proteolytic activity up to 27.4% of the initial value and it suggests that the enzyme is a serine protease. The activity was stimulated by Ca2+, Na+, Mg2+ and strongly inhibited by Hg2+, Cu2+, Zn2+ and Fe3+. Nonionic detergents like Triton X-100 and Tween 80 did not affect catalytic properties. It suggested that the enzyme produced by D. geothermalis could be used as a component of detergents.
Fabrication, Microstructure and High Temperature Corrosion Resistance of Porous Alloys for Solid Oxide Fuel Cells
- Sebastian Molin
- Katarzyna Dunst
- Magdalena Biczyńska
- Jakub Karczewski
- Piotr Jasiński
2013
Porous alloys find use in modern Solid Oxide Fuel Cells as the supporting structures. As they are exposed to high temperatures (> 500°C) an oxide scale forms on their surface due to high temperature corrosion phenomena. Since the ratio between the surface area and volume is much higher than for planar samples, formation of the oxide can lead to a breakaway oxidation after relatively short times. Therefore corrosion properties of possible candidate alloys should be studied. In this work corrosion kinetics of IN625 alloy is studied in the temperature range of 700°C – 800°C in air and hydrogen atmosphere for up to 100 hours. Moreover, a method of reducing corrosion rates of porous alloys by the infiltration of simple rare earths elements is shown. Modification by the Y precursor reduces corrosion rate by a factor of 50 in air at 700°C so that the lifetime of the infiltrated alloy is greatly extended.
Factors determining selection of production planning and control system
- Jolanta Łopatowska
2013
The article contains a comparative characteristics of selected systems of production planning and control, such as: MRP, kanban/JiT, DBR/TOC. The results of the performed analyses served as a basis for determining key market factors related to production planning and control functions, which determine the choice of an appropriate system.
Fast Collaborative Graph Exploration
- Dariusz Dereniowski
- Yann Disser
- Adrian Kosowski
- Dominik Pająk
- Przemysław Uznański
2013 LECTURE NOTES IN COMPUTER SCIENCE
We study the following scenario of online graph exploration. A team of k agents is initially located at a distinguished vertex r of an undirected graph. At every time step, each agent can traverse an edge of the graph. All vertices have unique identifiers, and upon entering a vertex, an agent obtains the list of identifiers of all its neighbors. We ask how many time steps are required to complete exploration, i.e., to make sure that every vertex has been visited by some agent. We consider two communication models: one in which all agents have global knowledge of the state of the exploration, and one in which agents may only exchange information when simultaneously located at the same vertex. As our main result, we provide the first strategy which performs exploration of a graph with n vertices at a distance of at most D from r in time O(D), using a team of agents of polynomial size k = D n^{1 + ε} < n^{2 + ε} , for any ε > 0. Our strategy works in the local communication model, without knowledge of global parameters such as n or D. We also obtain almost-tight bounds on the asymptotic relation between exploration time and team size, for large k. For any constant c > 1, we show that in the global communication model, a team of k = D n^c agents can always complete exploration in D(1+1/(c−1)+o(1)) time steps, whereas at least D(1+1/c−o(1)) steps are sometimes required. In the local communication model, D(1+2/(c−1)+o(1)) steps always suffice to complete exploration, and at least D(1+2/c−o(1)) steps are sometimes required. This shows a clear separation between the global and local communication models.
Fast High-Impedance Spectroscopy Method Using SINC Signal Excitation
- Michał Kowalewski
- Grzegorz Lentka
2013 Pełny tekst Metrology and Measurement Systems
In this paper the method of fast impedance spectroscopy of technical objects with high impedance (|Zx| > 1 Gohm) is evaluated by means of simulation and practical experiment. The method is based on excitation of an object with a sinc signal and sampling response signals proportional to current flowing through and voltage across the measured impedance. The object impedance spectrum is obtained with use of continuous Fourier transform on the basis of linear approximations between samples in two acquisition sections, connected with the duration of the sinc signal. The method is first evaluated in MATLAB by means of simulation. An influence of the sinc signal duration and the number of samples on impedance modulus and argument measurement errors is explored. The method is then practically verified in a constructed laboratory impedance spectroscopy measurement system. The obtained acceleration of impedance spectroscopy in low frequency range (below 1 Hz) and decrease of the number of acquired samples enable to recommend the worked out method for implementation in portable impedance analyzers destined for operation in the field.
FATE OF LAS SURFACT ANTS IN WWTPs BASED ON MEASURED CONCENTRATIONS IN WASTEWATER AND SLUDGE
- Elżbieta Hallmann
- Renata Tomczak-Wandzel
- Krystyna Mędrzycka
2013
The fate of the surfactant LAS in the two different types of Waste Water Treatment Plants has been reviewed: the small “Swarzewo” WWTP (45 000 PE), and large WWTP “Wschód” (760 000 PE). The elimination of LAS from the water stream in Swarzewo (98,7%), is better than that found in Gdańsk (97,6%). In the sludge treatment course, the reduction of LAS in Swarzewo is greater than that in Gdańsk due to the greater biodegradation of LAS surfactant in composting treatment that take place in Swarzewo WWTP.
Feature-based generation of machining process plans for optimised parts manufacture
- Mariusz Deja
- Mieczysław Siemiątkowski
2013 Pełny tekst JOURNAL OF INTELLIGENT MANUFACTURING
Przedstawiono aktualne zagadnienia związane z integracją systemów CAD/CAM/CAPP. Opracowano model informacyjny danych dla systemu CAPP w postaci zapisu macierzowego. Zawarto algorytm tworzenia rozwiązań wariantowych i wyboru optymalnego procesu technologicznego obróbki. Proponowany algorytm działania zweryfikowano na rzeczywistym przykładzie z praktyki przemysłu.
Features of Nonlinear Sound Propagation in Vibrationally Excited Gases
- Anna Perelomova
- Magdalena Kuśmirek-Ochrymiuk
2013 Pełny tekst Archives of Acoustics
Weakly nonlinear sound propagation in a gas where molecular vibrational relaxation takes place is studied. New equations which govern the sound in media where the irreversible relaxation may take place are derived and discussed. Their form depends on the regime of excitation of oscillatory degrees of freedom, equilibrium (reversible) or non-equilibrium (irreversible), and on the comparative frequency of the sound in relation to the inverse time of relaxation. Additional nonlinear terms increase standard nonlinearity of the high-frequency sound in the equilibrium regime of vibrational excitation and decrease otherwise. As for the nonlinearity of the low-frequency sound, the conclusions are opposite. Appearance of a non-oscillating additional part which is a linear function of the distance from the transducer is an unusual property of nonlinear distortions of harmonic at the transducer high-frequency sound.
Fecal indicators resistance to antimicrobial agents present in municipal wastewater
- Aneta Łuczkiewicz
- Krystyna Olańczuk-Neyman
- Ewa Felis
- Aleksandra Ziembińska
- Anna Gnida
- Joanna Surmacz-Górska
2013
In this study removal rate of six antimicrobial compounds (belonging to folate pathway inhibitors and macrolides class) was analyzed in processes of local wastewater treatment plant (WWTP) together with susceptibility patterns of erythromycin (E) resistant Enterococcus spp. and trimethoprim/sulfamethoxazole (SXT) resistant Escherichia coli. According to the obtained data, six of tested antimicrobial agents, namely erythromycin, clarithromycin, trimethoprim, roxithromycin, sulfamethoxazole and N-acetyl-sulfamethoxazole were detected in both raw and treated wastewater samples. Among tested E. coli resistance to SXT was highly correlated with resistance to penicillins as well as to tetracycline (88% and 75%, respectively) while E-resistant E. faecalis and E. faecium showed significant differences in resistance patterns. Among tested isolates of wastewater origin resistance phenotype of clinical importance were detected. Thus, further study is needed to evaluate dissemination of antimicrobial resistance via treated wastewater.