2015 - Repozytorium publikacji - Politechnika Gdańska

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ANALYSIS OF BRACE STIFFNESS INFLUENCE ON STABILITY OF THE TRUSS
- Marcin Krajewski
- Piotr Iwicki
2015 Pełny tekst International Journal of Applied Mechanics and Engineering
The paper is devoted to the numerical and experimental research of stability of a truss with side elastic supports at the top chord. The structure is a model of a real roof truss scaled by factor ¼. The linear buckling analysis and non-linear static analysis were carried out. The buckling length factor for the compressed top chord was calculated and the limit load for the imperfect truss shell model with respect to brace stiffness was obtained. The relation between brace normal force and loading of the truss is presented. The threshold stiffness of braces necessary to obtain the maximum buckling load was found. The truss load bearing capacity obtained from numerical analysis was compared with Eurocode 3 requirements.
Analysis of electromagnetic disturbances in DC network of grid connected building-integrated photovoltaic system
- Marcin Ruciński
- Piotr Chrzan
- Piotr Musznicki
- Jean-Luc Schanen
- Antoine Labonne
2015
This paper focuses on conducted electromagnetic interference (EMI) emissions and propagation in the DC network of grid connected building integrated photovoltaic (PV) system. The investigated PV system, consists of ten solar panels, cabling and the grid-connected one phase inverter. The EMI simulation model of the real PV system has been developed with the aid of impedance analyzer measurements of solar panels and the DC network cable. Simulation study was carried out in the LTspice software environment. Next, the common and differential mode disturbances paths impedances (seen from inverter terminals), were calculated by two methods. First method was based on voltage and current spectra obtained during PV system operation. The second method resulted from impedance measurement at the disconnected inverter terminals. Comparison of simulation and experimental differential and common mode paths impedances indicates coherency level strongly dependent of the EMI frequency range.
Analysis of impact of audio modifications on the robustness of watermark for non-blind architecture
- Janusz Cichowski
- Andrzej Czyżewski
- Bożena Kostek
2015 Pełny tekst MULTIMEDIA TOOLS AND APPLICATIONS
The aim of this paper is to assess the robustness of the non-blind audio content watermarking scheme proposed by the authors. The authors present the architecture of the designed system along with the employed workflows for embedding and extracting the watermark followed by the implementation phase description and the analysis of the experimental results. Some possible attack simulations on the embedded watermarks are reviewed, and the robustness of the proposed approach is evaluated in the context of the influence of lossy compression on the watermark degradation. Subjective and objective analyses are performed for the algorithm proposed by the authors and compared with the Audio Watermarking Tools (AWT) encoder. Finally, the advantages and drawbacks of the proposed approach are debated followed by the conclusion section outlining possible improvements to the proposed method.
Analysis of Interspike-Intervals for the General Class of Integrate-and-Fire Models with Periodic Drive
- Justyna Signerska-Rynkowska
2015 Pełny tekst Mathematical Modelling and Analysis
We study one-dimensional integrate-and-fire models of the general type x˙=F (t, x) and analyze properties of the firing map which iterations recover consecutive spike timings. We impose very week constraints for the regularity of the function F (t, x), e.g. often it suffices to assume that F is continuous. If additionally F is periodic in t, using mathematical study of the displacement sequence of an orientation preserving circle homeomorphism, we provide a detailed description of the regularity properties of the sequence of interspike-intervals and behaviour of the interspike-interval distribution.
Analysis of positioning error and its impact on high frequency properties of differential signal coupler
- Marek Zmuda
- Stanisław Szczepański
- Sławomir Kozieł
2015 Pełny tekst Bulletin of the Polish Academy of Sciences-Technical Sciences
This paper presents the analysis of the effect of differential signal coupler positioning accuracy on its high frequency performance parameters for contact-less high speed chip-to-chip data transmission on PCB application. Our considerations are continuation of the previous works on differential signal coupler concept, design methodology and analysis for high speed data transmission monitoring. The theoretical analysis of possible coupler positioning innaccuracies is extended for representative design cases by simulations carried out using EM simulator. The results reported here confirm that the concept of contactless monitoring of high speed chip-to-chip data transmission in a pair of coupled microstrip lines is of practically usefulness without applying the expensive and precise positioning system.
ANALYSIS OF POSSIBILITIES FOR THE USE OF VOLUME-DELAY FUNCTIONS IN THE PLANNING MODULE OF THE TRISTAR SYSTEM
- Jacek Oskarbski
- Kazimierz Jamroz
- Leszek Smolarek
- Michał Miszewski
- Marcin Zawisza
2015
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Analysis of radiation and scattering problems with the use of hybrid techniques based on the discrete Green's function formulation of the FDTD method
- Tomasz Stefański
- Sławomir Orłowski
- Bartosz Reichel
2015
In this contribution, simulation scenarios are presented which take advantage of the hybrid techniques based on the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method. DGF-FDTD solutions are compatible with the finite-difference grid and can be applied for perfect hybridization of the FDTD method. The following techniques are considered: (i) DGF-FDTD for antenna simulations, (ii) DGF-based FDTD on disjoint domains, and (iii) hybrid technique combining FDTD and its convolution formulation based on DGF. The presented research employs the new formulation of the FDTD-compatible dyadic DGF derived with the use of scalar DGF and the multidimensional Z-transform. Its software implementation is straightforward because only elementary functions are involved and a single function requires computations in the multiple-precision arithmetic.
ANALYSIS OF THE INCREASE OF CONSTRUCTION COSTS IN URBAN REGENERATION PROJECTS
- Magdalena Apollo
- Emilia Miszewska
2015 Pełny tekst Advances in Science and Technology Research Journal
The subject of this paper is the analysis and evaluation of the reasons for construction costs increases in urban regeneration projects. The analysis considers major refurbishments of real estates’, as well as heavy repair and modernization of the road system. For the period mentioned, the costs from works and expenditure schedules were compared with the costs of additional works, which shows the percentage cost increase in relation to initial project budget assumptions of the case study. The analysis revealed that due to difficulties in assessing technical state of inhabited buildings, the investor and potential contractor should pay special attention to the character of issues presented in this paper, taking into account an increased risk of their occurrence.
ANALYSIS OF THE p53 PROTEIN GENE EXPRESSION MODEL
- Agnieszka Bartłomiejczyk
- Marek Bodnar
- Monika Piotrowska
2015
We study the asymptotic behaviour of the solutions of the p53-Mdm2 model proposed by Monk (2003). The p53 gene is crucial for cellular inhibition of the angiogenesis process, while Mdm2 is a negative regulator of the p53 tumor-suppressor. We investigate the stability of the positive steady state and perform some numerical experiments.
Analysis of the possibility of increasing thermal-electric energy conversion ratio in CHP units based on micro gas turbine
- Tomasz Kowalczyk
- Janusz Badur
2015
The aim of this paper is to analyze the possibility of increasing thermal energy to electricity conversion efficiency in combined heat and power (CHP) units based on micro gas turbine during low heat demand periods. At the beginning sustainable development postulates under power engineering are explained. Next micro CHP as part of distributed generation idea is presented. The main part of the article is based on results of thermodynamic and preliminary flow calculation for micro steam turbine cooperating with Capstone C200 micro gas turbine. An analysis of ’hot beginning’ and ’cool end’ of the turbine parameters due to flow limits is carried out. The ending contains a summation of the calculation results and a conclusion about combining steam and gas micro generating units.
Analysis of unsteady flow forces on the thermowell of steam temperature sensor
- Sebastian Kornet
- Daniel Sławiński
- Paweł Ziółkowski
- Janusz Badur
2015 Transactions of the Institute of Fluid-Flow Machinery
In this paper, 3D numerical analysis of unsteady flow forces acting on the measuring sheath of steam temperature is presented. According to that purpose, the CFD (Computation Fluid Dynamic [1]) approach has been used. The nonstationary of fluid acting on the measuring sheath such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity etc. are studied analytically and numerically. Examined two cases of flow with changing both temperature, pressure and mass flow rate (operating daily and night in the unit with capacity of 373 MWe). The main aim of the paper is to refer to the standards of ASME PTC 19.3 TW-2010 [2]. We should add that a large number of experimental and numerical studies [3-7] of the wake behind the obstacles and vortex induced vibration have been performed. In accordance with the standards ASME PTC 19.3 TW-2010 the possibility of entry into resonance has been examined.
ANALYSIS OF WORKING CONDITIONS OF BEARINGS NO.1 & NO.2 OF TURBINE 13K200 AND DESIGN DEVELOPMENT OF NEW BEARINGS FOR THE TURBINE AFTER RETROFITTING
- Artur Olszewski
2015
The main goal of the work consisted of preparing an analysis of working conditions of bearings No.1 and No.2 in the existing turbine 13K200, as well as designing geometries of new bearings which would allow for their proper functioning in the turbine following its retrofitting (work under higher load).
Analytical aspects of model compounds toxicity assessment using MTT and Microtox bioanalytica assays
- Błażej Kudłak
- Zofia Mazerska
- Jacek Namieśnik
- Katarzyna Owczarek
2015
More and more increased intensity of anthropopressure processes can be observed, among other things, in the release of great quantities of synthetic substances into the environment, including the Endocrine Disrupting Compounds. The effects of the above-mentioned human impact on the environment not only can be noticed in the homeostasis disturbance in ecosystems, but they are also visible with respect to human. The high incidence rate of cancer and other civilization diseases has become a serious social problem. Therefore, all attempts to broaden the knowledge about the relations and mechanisms triggering the development of relevant diseases are justified. The goal of the conducted research was to use bioanalytic methods to evaluate cytotoxicity and acute toxicity of the selected EDCs which cause serious food contamination (bisphenol A, 4-nonynphenol, 4-t-octylphenol, diethylstilbestrol, bisphenol A diglycidyl ether and its derivatives and phthalates) with MTT cel viability assay and Microtox® assay.
Analytical fluctuation enhanced sensing by resistive gas sensors
- Robert Macku
- Janusz Smulko
- Pawel Koktavy
- Maciej Trawka
- Petr Sedlak
2015 SENSORS AND ACTUATORS B-CHEMICAL
Resistance fluctuations across polarised resistive gas sensors were studied in detail to evaluate sensor working conditions for detecting methane and ammonia at various concentrations. The 1/f noise component typically dominates other noise sources up to a few kHz and can be utilised to improve gas selectivity when compared with measurements of the sensor DC resistance. The Arrhenius plot was created and the activation energy for the investigated gases was evaluated. Using this method, different ambient gases can be potentially detected only by means of a single commercial Taguchi gas sensor and 1/f noise measurements at different temperatures of the gas sensing layer without a need of intense computations to get reliable results.
Analytical method of determining dynamic properties of thermocouples used in measurements of quick – changing temperatures of exhaust gases in marine diesel engines
- Zbigniew Korczewski
- Patrycja Puzdrowska
2015 Pełny tekst Combustion Engines
The article presents selected issues of mathematical modeling of heat exchange between the thermocouple and the exhaust gas flowing them, in unsteady conditions. On the way of energy balancing consideration of thermodynamic processes developed differential equations describing the dynamic properties for three versions of the design sheathed thermocouples: with weld isolated from the sheath, with weld welded the sheath and with the open weld. On this basis were determined the equations describing the time constants. After substituting the appropriate the input data: materials and heat-flow, provided by the manufacturer (the company "TermoPrecyzja") it was possible to compare the numerical values of the time constants of thermocouples and make a rational choice for the diagnostic tests conducted marine diesel engines.
Android OS: A Review
- Przemysław Falkowski-Gilski
- Jacek Stefański
2015 Pełny tekst Tem Journal
Due to the technological development, mobile terminals have evolved into functionally sophisticated devices such as smartphones and tablets. The Android platform has become one of the most popular operating system with millions of new users each year. Despite many studies, none have provided a comprehensive description of this operating system. In this paper we present a review of the Android OS. We describe the platforms history including improvements involved in each release as well as the systems architecture and project structure.
Anharmonic Infrared Spectroscopy through the Fourier Transform of Time Correlation Function Formalism in ONETEP
- Valerio Vitale
- Jacek Dziedzic
- Simon Dubois
- Hans Fangohr
- Chris-Kriton Skylaris
2015 Journal of Chemical Theory and Computation
Density functional theory molecular dynamics (DFT-MD) provides an efficient framework for accurately computing several types of spectra. The major benefit of DFTMD approaches lies in the ability to naturally take into account the effects of temperature and anharmonicity, without having to introduce any ad hoc or a posteriori corrections. Consequently, computational spectroscopy based on DFT-MD approaches plays a pivotal role in the understanding and assignment of experimental peaks and bands at finite temperature, particularly in the case of floppy molecules. Linear-scaling DFT methods can be used to study large and complex systems, such as peptides, DNA strands, amorphous solids, and molecules in solution. Here, we present the implementation of DFT-MD IR spectroscopy in the ONETEP linear-scaling code. In addition, two methods for partitioning the dipole moment within the ONETEP framework are presented. Dipole moment partitioning allows us to compute spectra of molecules in solution, which fully include the effects of the solvent, while at the same time removing the solvent contribution from the spectra.
ANODOWE WARSTWY KATALITYCZNE DLA TLENKOWYCH OGNIW PALIWOWYCH ZASILANYCH BIOGAZEM
- Chlewińska Magdalena
- Niańkowski Dominik
- Tadeusz Miruszewski
- Beata Bochentyn
2015
W pracy wytworzono materiały (LiLaNi-Al2O3) oraz (Sm0.2Ce0.8O1.9), jako potencjalne katalizatory reakcji reformingu biogazu w tlenkowych ogniwach paliwowych. Syntezę przeprowadzono metodą Pechini’ego. Zbadano skład chemiczny oraz strukturę uzyskanych związków. Ponadto ogniwo sprawdzono podczas pracy z biogazem pod kątem odporności na osadzenie węgla, a także wpływu na długość pracy ogniwa.
Antibiotic resistance and prevalence of class 1 and 2 integrons in Escherichia coli isolated from two wastewater treatment plants, and their receiving waters (Gulf of Gdansk, Baltic Sea, Poland)
- Ewa Kotlarska
- Aneta Łuczkiewicz
- Marta Pisowacka
- Artur Burzyński
2015 Pełny tekst ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
In this study, antimicrobial-resistance patterns were analyzed in Escherichia coli isolates from raw (RW) and treated wastewater (TW) of two wastewater treatment plants (WWTPs), their marine outfalls (MOut), and mouth of the Vistula River (VR). Susceptibility of E. coli was tested against different classes of antibiotics. Isolates resistant to at least one antimicrobial agent were PCR tested for the presence of integrons. Ampicillin-resistant E. coli were the most frequent, followed by amoxicillin/clavulanate (up to 32 %), trimethoprim/sulfamethoxazole (up to 20 %), and fluoroquinolone (up to 15 %)-resistant isolates. Presence of class 1 and 2 integrons was detected among tested E. coli isolates with rate of 32.06 % (n = 84) and 3.05 % (n = 8), respectively. The presence of integrons was associated with increased frequency of resistance to fluoroquinolones, trimethoprim/sulfamethoxazole, amoxicillin/clavulanate, piperacillin/tazobactam, and presence of multidrug-resistance phenotype. Variable regions were detected in 48 class 1 and 5 class 2 integron-positive isolates. Nine different gene cassette arrays were confirmed among sequenced variable regions, with predominance of dfrA1-aadA1, dfrA17-aadA5, and aadA1 arrays. These findings illustrate the importance of WWTPs in spreading of resistance genes in the environment and the need for inclusion of at least monitoring efforts in the regular WWTP processes.
Antimicrobial properties of chitosan solutions, chitosan films and gelatin-chitosan films
- Edyta Malinowska-Pańczyk
- Hanna Staroszczyk
- Karolina Gottfried
- Ilona Kołodziejska
- Anna Wojtasz-Pająk
2015 Pełny tekst Polimery
The antimicrobial properties of chitosan solutions and films against selected bacteria and the effect of chitosan incorporation into gelatin films were studied. The bactericidal effect of chitosan solutions increased with time and temperature of sample incubation. Two psychrotrophic strains Pseudomonas fluorescens and Listeria innocua were more sensitive to chitosan than mesophilic strains Escherichia coli and Staphylococcus aureus. The growth of bacteria under chitosan discs was inhibited. In the case of two component gelatin-chitosan films strong antimicrobial effect was also observed.