2013 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2013

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Mathematical Models of Control Systems of Angular Speed of Steam Turbines for Diagnostic Tests of Automatic and Mechatronic Devices
- Grzegorz Redlarski
- Janusz Piechocki
- Mariusz Dąbkowski
2013 Solid State Phenomena
Accurate modeling of physical processes of many automatics and mechatronics systems is often necessity. In power system such a process is control of angular velocity of power objects during connection to operation in parallel. This process is extremely dynamic. For this reason response of control system depends from changes of many physical parameters (temperature, pressure and flow of the medium, etc.). Precision modeling influences on testing process of automatic synchronizer in the laboratory, as well as the evaluation of possibility of connection process (realized without the automatic synchronizer). On the other hand complex ststems to tests and monitoring of the automatic automatic synchronizers are known, in the literature, as simulators. Hence to impose real conditions at work required to implement an appropriate models of control systems. One of such models - representative for the larger population of objects - is model of control systems of angular velocity. Previously described models, allow to approximate the response of real object or to impose higher restricted conditions at work. Furthermore their usage requires detailed knowledge of the object, and frequently, even time-consuming selection of manual procedure of certain substitute settings. In this paper to eliminate above inconveniences, the new mathematical modeling procedure has been presented. This allow in easy way to obtain much more accurate transitional characteristics of real objects.
Maturity Mismatch in the Polish Banking System and its Impact on the Economy
- Błażej Kochański
2013
In the article maturity mismatch in the Polish banking system is estimated based on the publicly available data. Then the impact on the economy is discussed. Based on Polish central bank’s data it may be estimated that between 1996 and 2012 the maturity gap increased significantly – average residual maturity of assets exceeds 6 years in 2012 (less than 2 years in 1996), while that of liabilities remains below 1 year. The gap between assets and liabilities is even wider if we take into account the fact that due to legal constraints practically all deposits in Poland are callable. Growing maturity mismatch in a particular bank may result in higher credit, liquidity, legal, model, interest rate and other risks. Risks accepted by banks may then propagate through the economy, which may lead to financial instability. Increasing gap affects monetary aggregates; additional imbalances catalyze asset bubbles, e.g. a boom in house prices. Also, it could be claimed that maturity mismatch distorts the economic incentives through lowered interest rates. Special case of the maturity mismatch is constituted in Poland by foreign currency denominated mortgages funded with short-term local currency deposits and hedged with short-term swaps.
MEAN SHIFT BASED SEGMENTATION FOR BLEEDING REGIONS IN ENDOSCOPIC VIDEOS
- Adam Brzeski
- Adam Blokus
- Jan Cychnerski
2013
With a set of 38 manually marked bleeding regions form endoscopic videos, the authors attempted to find an optimal image segmentation method for reproducing doctor’s markup. Mean shift segmentation combined with HSV histogram segmentation were used as a segmentation method, which was then optimized by tuning the parameters of the method using global optimization algorithm. A target function for measuring the quality of segmentation was proposed. The research resulted in a segmentation method for bleeding regions with similarity rate of 74% compared to the doctor’s markup.
MEASURE OF THE LEVEL OF SOCIO-ECONOMIC DEVELOPMENT IN PROVINCES
- Aneta Sobiechowska-Ziegert
- Aniela Mikulska
2013 Pełny tekst Metody Ilościowe w Badaniach Ekonomicznych
The scope of Polish macro-economic data for assessing the level of socio-economic development of the country is largely limited because of the regional variation. Therefore there is a need for cyclic selection and the verification of criteria which allow identifying regions with a similar level of socio-economic development or those that clearly differ from the mean values. The aim of the study is to compare Poland’s provinces in terms of their socio-economic development, which helps identify the most similar regions as far as the adopted criteria are concerned.
Measurement methods for assessing insulation condition of underground pipelines
- Krzysztof Żakowski
2013 Ochrona przed Korozją
The paper discusses the most frequently applied measurement methods for assessing the quality of external insulation along pipelines and detecting defect locations in the protective coating. The quality of coating along a given pipeline section under investigation is assessed by determining unitary resistance of the coating, which is calculated on the basis of measurement results obtained along a pipeline subjected to cathodic polarization. In order to locate defects in insulation of pipelines, methods consisting in measurements of direct current voltage gradient (DCVG) or alternative current voltage gradient (ACVG) are used, mainly on the ground surface for pipelines subjected to polarization by dc or ac current.
Measurement of complex refractive index of human blood by low-coherence interferometry
- Małgorzata Szczerska
2013 Pełny tekst The European Physical Journal-Special Topics
In this article, the usefulness of the optical technique for measurements of blood complex refractive index has been examined. Measurement of optical properties of human blood is difficult to perform because of its nonuniform nature. However, results of my investigation have shown the usefulness of low-coherencei nterferometry for measurement complex refractive index of human blood. Furthermore, mathematical analysis of spectrum of measured signal have made possible to determined relationship between complex refractive index and hematocrit level in human blood.
Measurement system for nonlinear surface spectroscopy by atomic force microscopy for corrosion processes monitoring
- Sylwia Babicz-Kiewlicz
- Artur Zieliński
- Janusz Smulko
- Kazimierz Darowicki
2013
In addition to traditional imaging the surface, atomic force microscopy (AFM) enables wide variety of additional measurements. One of them is higher harmonic imaging. In tapping mode the nonlinear contact between tip and specimen results in higher frequency vibrations. More information available from the higher harmonics analysis proves to be helpful for more detailed imaging. Such visualization is especially useful for heterogeneous surfaces which are studied to understand corrosion mechanisms. In this paper the measurement system for nonlinear surface spectroscopy by AFM for corrosion processes monitoring is presented.
Measurements of acoustic crosstalk cancellation efficiency in mobile listening conditions
- Kuba Łopatka
- Andrzej Czyżewski
2013
The cancellation of acoustic crosstalk is employed to enhance the stereo image in mobile listening conditions. The implementation of the crosstalk cancellation algorithm in Matlab is introduced. The measurement signals and equipment are described. A practical setup employing a mobile computer and a head and torso simulator is employed. The results of the measurements provided conclusions regarding the employment of acoustic crosstalk cancellation in mobile computers.
Measurements of Spectral Spatial Distribution of Scattering Materials for Rear Projection Screens used in Virtual Reality Systems
- Adam Mazikowski
- Michał Trojanowski
2013 Pełny tekst Metrology and Measurement Systems
Rapid development of computing and visualisation systems has resulted in an unprecedented capability to display, in real time, realistic computer-generated worlds. Advanced techniques, including three-dimensional (3D) projection, supplemented by multi-channel surround sound, create immersive environments whose applications range from entertainment to military to scientific. One of the most advanced virtual reality systems are CAVE-type systems, in which the user is surrounded by projection screens. Knowledge of the screen material scattering properties, which depend on projection geometry and wavelength, is mandatory for proper design of these systems. In this paper this problem is addressed by introducing a scattering distribution function, creating a dedicated measurement setup and investigating the properties of selected materials used for rear projection screens. Based on the obtained results it can be concluded that the choice of the screen material has substantial impact on the performance of the system
Measurements of Subnanometer Molecular Layers
- Maciej Kokot
2013
Selected methods of formation and detection of nanometer and subnanometer molecular layers were shown. Additionally, a new method of detection and measurement with subnanometer resolution of layers adsorbed or bonded to the gate dielectric of the ion selective field effect transistor (ISFET) was presented.
Measuring radioactive powder samples on the highresolution powder diffraction beamline at the European Synchrotron Radiation Facility
- Adrian Hill
- Tomasz Klimczuk
- Ross Springell
- Helen Walker
2013 Journal of Applied Crystallography
This laboratory note describes a new sample preparation technique to enable high-resolution powder diffraction experiments at the European Synchrotron Radiation Facility on radioactive samples. The sample preparation involves setting the active material in resin and several layers of encapsulation suitable for measurement at the beamline. This has allowed low-temperature measurements on very small quantities of samples, providing new insights into materials that are notoriously difficult to measure elsewhere.
Measuring the density of DNA films using ultraviolet-visible interferometry
- Małgorzata Śmiałek-Telega
- Nykola C. Jones
- Soren Vronning Hoffmann
- Nigel J. Mason
2013 Pełny tekst PHYSICAL REVIEW E
In order to determine a proper value for the density of dry DNA films we have used a method based upon the measurement of interference effects in transmission spectra of thin DNA layers. Our results show that the methodology is effective and the density of DNA in this state, 1.407 g/cm3, is much lower than the commonly used 1.7 g/cm3. Obtaining accurate values for the DNA film density will allow the optical constants for DNA to be recalculated, which were previously obtained assuming a higher DNA density. Furthermore, since our recent investigations have shown a strong dependence of the sample composition on DNA film formation and thus on its density, such a method will be important in characterizing particle interactions with DNA film and their dose dependence.
Mechanical behaviour of the implant used in human hernia repair under physiological loads
- Katarzyna Szepietowska
- Izabela Lubowiecka
2013 Pełny tekst Acta of Bioengineering and Biomechanics
In laparoscopic operations of abdominal hernias some recurrences still take place, even when applying a surgical mesh. This is usually caused by a failure of the connection between the tissue and the implant. The study deals with the influence of an implant’s orientation on forces in joints, which connect the mesh to human tissues. In the paper, the implant is modelled as a membrane structure within framework of the Finite Element Method. Two models are analysed: in the first one interaction between the mesh and a fascia is taken into account, in the second this interaction is not considered. Computations are conducted for two different material types of the implants: one with isotropic properties and second one with orthotropic properties. The models are validated by comparing dynamic numerical analysis with experimental outcomes, where load was simulating intraabdominal pressure during postoperative cough. Due to displacements of joints during activities like bending sideways or torsion of an abdomen, influence of kinematic extortions on forces in the joints is analysed. The outcome shows that position of the orthotropic implants is crucial and may strongly change the level of forces in the joints
MECHANICAL PROPERTIES OF BOTTOM ASH – DREDGED MATERIAL MIXTURES IN LABORATORY TESTS
- Lech Bałachowski
- Zbigniew Sikora
2013 Pełny tekst Studia Geotechnica et Mechanica
Bottom ash from EC Gdańsk and dredged material taken from the mouth of The Vistula were mixed to form an engineering material used for dike construction. Mixtures with different bottom ash content were tested in laboratory to determine its basic physical and mechanical properties. The optimum bottom ash–dredged material mixture, built in the corps of the test dike, contains 70% of ash. The optimum bottom ash content in the mixture was chosen taking into account high internal friction angle, good compaction and reduced filtration coefficient. The maximum dry density of the mixtures was measured in Proctor test for the mixtures formed in laboratory and on samples taken from the test dike. Minimum and maximum void ratio were also determined.
Mechanical properties of sisal fiber-reinforced soybean oil-based polyurethane biocomposites
- Ewa Głowińska
- Janusz Datta
- Justyna Kamerke
2013
In this paper the results of the mechanical properties of polyurethane biocomposites reinforced with short sisal fibers are presented. The fillers were added in different amount: 5, 10 and 15% by mass. Tensile test, hardness, abrasion resistance, elasticity were determined according to the standards.
Mechanical testing of technical woven fabrics
- Andrzej Ambroziak
- Paweł Kłosowski
2013 JOURNAL OF REINFORCED PLASTICS AND COMPOSITES
This article presents a review of technical fabrics testing methods used by the authors on the basis of their experience with research on properties of polytetrefluoroethylene-coated fabrics used for Forest Opera in Sopot (Poland). First, the different types of testing methods used for description of mechanical properties (uniaxial tensile tests, biaxial tensile tests and shear tests) of technical woven fabrics are described. The authors present the collection of test methods and discuss the results of these tests for different fabrics. Finally, the effects of temperature on mechanical properties are studied.
Mechanical, thermo-mechanical properties of epoxy/glass composites with submicron particles
- Janusz Datta
- Marcin Włoch
2013
In this research the influence of submicron zinc oxide and silicon dioxide particles on mechanical, thermo-mechanical properties of epoxy matrix composites reinforced with glass fibres was investigated. Composites were fabricated using hand lay-up method. Materials contained 39-41 wt.% of glass fibres. The bending tests, dynamic mechanical analysis and tribological tests were performed on each group of composites and also for reference samples (without submicron particles). The results showed that 2 wt.% addition of silica or 4 wt.% of zinc oxide to epoxy matrix improved the flexural strength and flexural modulus of composites. DMA investigation showed increasing of storage and loss modulus, for mentioned content of submicron particles. It can be attributed to the good dispersion and interaction between particles and polymer matrix. It was also found that addition of submicron silica particles increased of abrasion resistance.
Mechanism of the Reaction of Amines with 5-[(Aryl- or Alkylamino)hydroxymethylene]-2,2-dimethyl-1,3-dioxane-4,6-diones in the Presence of Chlorotrimethylsilane (Me3SiCl);
- Karolina Janikowska
- Sławomir Makowiec
- Janusz Rachoń
2013 Pełny tekst HELVETICA CHIMICA ACTA
Addition of chlorotrimethylsilane (Me3SiCl) to the mixture of a carbamoyl‐substituted Meldrum's acid, i.e., a 5‐[(arylamino)hydroxymethylene]‐2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione of type 1 and a secondary amine as nucleophile strongly accelerated the rate of their reaction. The reason for this phenomenon observed, during our previous research, remained, however, unclear. To elucidate the mechanism of this reaction, we assumed and verified three possible pathways for the action of Me3SiCl (cf. Scheme 2): The acceleration of the reaction is caused i) by formation of a O‐trimethylsilylated Meldrum's acid of type 2, ii) by the silylated amine 3, or iii) by the presence of HCl liberated from Me3SiCl. The performed experiments revealed that the faster course of reaction is caused by the formation of N‐trimethylsilylated amines of type 3.
Mechanizmy odkrywania usług i integracji międzysieciowej w samoorganizujących systemach bezprzewodowych standardu IEEEE 802.11s
- Krzysztof Gierłowski
2013 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
Wobec gwałtownie rosnącej popularności urządzeń mobilnych rośnie również zainteresowanie bezprzewodowymi systemami dostępowymi. Wśród nich ciekawą propozycją są systemy sieci samoorganizujących się typu mesh, których przykładem może być standard IEEE 802.11s. W artykule przedstawiono propozycje rozbudowy wybranych jego mechanizmów, w wyraźny sposób zwiększające efektywność współpracy sieci mesh z sieciami zewnętrznymi oraz rozwiązaniami aplikacyjnymi zrealizowanymi w architekturze klient-serwer.
Media społecznościowe a wizerunek marki
- Magdalena Brzozowska-Woś
2013 Zarządzanie i Finanse
Jeszcze do niedawna wydawało się, że social media, podobnie jak komunikatory internetowe, będą stanowiły kolejne narzędzie wykorzystywane w komunikacji ze znajomymi, a ich tematyka będzie związana głównie z rozrywką i chęcią podtrzymania więzi społecznych. Jednak, z obserwacji wielu autorów wynika, iż obecnie można już mówić o trendzie social media lub też Web 2.0, a z roku na rok internetowe witryny o charakterze społecznościowym, podobnie jak komunikacja mobilna, stają się coraz bardziej popularne. Media społecznościowe przekształciły się w bazy informacji, z których można czerpać wiedzę i w których ludzie mogą wymieniać się opiniami dotyczącymi różnorodnej tematyki. Dlatego obecnie działania kreujące i wzmacniające wizerunek marki, a co za tym idzie organizacji lub produktów, nie mogą pomijać obszaru social media. Celem artykułu jest ukazanie wagi prowadzenia profilu biznesowego w serwisie społecznościowym zgodnie z potrzebami jego użytkowników, z uwagi na wpływ profilu na wizerunek promowanej w ten sposób marki.