2015 - Repozytorium publikacji - Politechnika Gdańska

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Study of Noise Propagation for Small Vessels
- Mateusz Weryk
- Eugeniusz Kozaczka
- Grażyna Grelowska
2015 Pełny tekst Archives of Acoustics
The paper presents the results of the noise propagation analysis in ship structures tested in a number of AHTS (Anchor Handling Tug Supply) vessels. Statistical Energy Analysis (SEA) based on numerical model developed specially for the purpose of this numerical investigation were conducted. This numerical model enabled the analysis of both the structural elements and the acoustic spaces. For the detailed studies 47 points fixed at various ship locations were selected. Prediction results with use of the numerical model were compared with the experimental results carried out in six identical AHTS vessels. Experimental studies were performed in accordance with the requirements of the International Maritime Organization (IMO) Resolution A.468 (XII). As a result one presented a comparison of the model analysis and experimental tests results.
Study of the effect of thermally reduced graphene oxide on the physical and mechanical properties of flexible polyurethane foams
- Łukasz Piszczyk
- Michał Strankowski
- Paulina Kosmela
2015 POLYMER COMPOSITES
Flexible polyurethane foams were obtained from a two-component system via the one-step method. The foams were modified with thermally reduced graphene oxide added in the amount equal to 0.25, 0.5 and 0.75 wt%. The morphology, static and dynamic properties, and thermal stability of modified foams were determined. The application of carbon filler resulted in the visible increase in the cell size, apparent density and rigidity of the modified systems, as confirmed by the measurements of glass transition temperature. Glass transition temperature increased with increasing content of nanofiller. Also, thermally reduced graphene oxide had an effect on the thermal stability of the obtained foam systems. The addition of 0.5 wt% of nanofiller resulted in an increase in T5 by 16ºC compared to the reference foam. This study also demonstrated that after exceeding a specific content of thermally reduced graphene oxide, i.e. 0.5%, the physicochemical properties of the obtained systems start to deteriorate. The research results showed that thermally reduced graphene oxide can be successfully used as a modifier of mechanical and thermal properties in flexible polyurethane foams.
Study of the Operation of Synchronous Generator Voltage Regulator During the Creation of Post Blackout Start-up Path
- Robert Małkowski
- Stanisław Czapp
- Robert Kowalak
- Maciej Łosiński
2015
This paper presents the influence of automatic voltage regulator (AVR) of synchronous generator on the process of creation of post black-out start-up path. Two elements of AVR have a significant impact on this process: underexcitation limiter (UEL) and load compensation (LC). The authors present a theoretical investigation and simulation results that illustrate how the mentioned elements of AVR affect voltage levels in a power system during the creation of start-up path. The results of the study show that present procedures of the preparation of start-up path in Polish Power System should be modified.
Subcritical bifurcation of free elastic shell of biological cluster
- Hanna Guze
- Joanna Janczewska
2015 NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS
In this paper we will investigate symmetry-breaking bifurcation of equilibrium forms of biological cluster. A biological cluster is a two-dimensional analogue of a gas balloon. The cluster boundary is connected with its kernel by elastic links. The inside part is filled with compressed gas or fluid. Equilibrium forms of biological cluster can be found as solutions of a certain second order ordinary functional-differential equation with four physical parameters: an elasticity coefficient of boundary, an elasticity coefficient of links and two parameters describing compressed gas or fluid. For each multiparameter, this equation possesses a radially symmetric solution. Applying a finite-dimensional reduction and a key function method we will prove the subritical behaviour of biological cluster.
Submerged objects modeling and storing in a global reference context using multiresolution spline technique,
- Jerzy Demkowicz
2015 Pełny tekst HYDROACOUSTICS
Contemporary records from multibeam sonars or even elevations from 3D shuttle radar topography missions feature high resolution. On the other hand, bathymetric models of a different resolution from different sensors are available as well, beginning from very high resolution MBS records and low resolution records coming from regular scattered measurements. Approximating and eventually visualizing the high volume scattered 3D raster data of different resolutions results in some difficulties related to the extent of computer processing power. The paper presents some advantages of using multiresolution splines combined with the Hilbert curve approach in the context. The proposed approach consists of two stages: firstly, data pertaining to different resolutions are interpolated using the spline technique and finally the knots and control points are saved using the Hilbert curve. Such an approach particularly facilitates high volume spatial data for the level of details (LoD)visualization technique.
Subsoil degradation effect in reliability analysis of the jack-up platform structure
- Bogdan Rozmarynowski
- Marek Krzysztof Jasina
2015 Pełny tekst Logistyka
Structural reliability analysis is considered, by FORM and SORM applied to a certain idealized soil-platform structure interaction problem due to cyclic water wave and wind loads. Wave and wind loads are random variables, whereas dead load is deterministic. Load parameters are typical for storm conditions in the Baltic Sea. The soil-structure interaction is idealized as a set of linear translational and rotational springs. Due to a cyclic type of wave loads, the contact area between the structure and subsoil reveals a degradation phenomenon expressed as Young’s modulus degradation. Numerical calculations of β index provide practical conclusions
Super Dominating Sets in Graphs
- Magdalena Lemańska
- V. Swaminathan
- Y. Venkatakrishnan
- R. Zuazua
2015 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES
In this paper some results on the super domination number are obtained. We prove that if T is a tree with at least three vertices, then n2≤γsp(T)≤n−s, where s is the number of support vertices in T and we characterize the extremal trees.
Superconductivity in the niobium-rich compound Nb5Se4
- Tomasz Klimczuk
- K. Baroudi
- J.w. Krizan
- Agnieszka Kozub
- R.j. Cava
2015 JOURNAL OF ALLOYS AND COMPOUNDS
The niobium rich selenide compound Nb5Se4 was synthesized at ambient pressure by high-temperature solid–state reaction in a sealed Ta tube. Resistivity and heat capacity measurements reveal that this compound is superconducting, with a Tc = 1.85K. The electronic contribution to the specific heat γ and the Debye temperature are found to be 18.1 mJmol−1K−2 and 298 K respectively. The calculated electron-phonon coupling constant λep = 0.5 and the ΔCp/γTc = 1.42 ratio imply that Nb5Se4 is a weak coupling BCS superconductor. The upper critical field and coherence length are found to be 1.44 T and 15.1 nm, respectively.
Surface sediments pollution due to shipwreck s/s “Stuttgart”: a multidisciplinary approach
- Justyna Rogowska
- Błażej Kudłak
- Stefan Tsakovski
- Agnieszka Gałuszka
- Gabriela Bajger-Nowak
- Vasil Simeonov
- Piotr Konieczka
- Lidia Wolska
- Jacek Namieśnik
2015 STOCHASTIC ENVIRONMENTAL RESEARCH AND RISK ASSESSMENT
Shipwrecks may pose a serious source of pollution for marine ecosystems. For this reason, it is of great importance to perform a marine ecosystem risk assessment due to plausible wreck presence. One of elements of such an assessment is determining the state of the environment in the vicinity of the wreck. In the work presented, the results of studies on surface sediments samples collected around the s/s Stuttgart ship sunk during WW2 in the Gulf of Gdan´sk (Southern Baltic) are given. 23 samples of sediments were collected and subsequently 12 metals (Cd, Co, Cr, Cu, Fe, Hg, Mg, Mo, Ni, Pb, V, Zn), 16 PAHs and 7 PCBs were determined. Metals were measured with ICPMS and AAS while organics with GC–MS. The chemometric evaluation was performed in order to determine possible similarity patterns between the chemicals measured. Clear dependence between PAHs and PCBs was stated as well as spatial similarities between the content of the chemicals determined.
Surface treatment of C80U steel by long CO2 laser pulses
- Anna Bień
- Marek Szkodo
2015 Pełny tekst JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
The paper presents the results of laser-melted C80U steel. The processed steel was placed between two permanent magnets and laser beam whose scanning velocity was 10 mm/s. CO2 laser beam was working in pulse mode. Pulses were generated at 100% of the average preset power of 700W, with 45 ms irradiation, zero interval between pulses and beginning of pulse repetition upon the achievement of the average laser power. During the operation, the laser beam generated plasma. The cyclic process of plasma generation induced by long laser pulses was validated experimentally with the use of a high-speed camera. Calculated speed of the plasma propagation velocity was 5.255 × 102 cm/s. The melted path had characteristic “folds”, and it comprised of a series of overlapping melted areas. The distance between adjacent “folds” correlated with beam displacement velocity which indicates that plasma plumes were generated cyclically atthe beginning ofthe generation of successive laser pulses. Hardness test ofthe processed steel revealed that surface irregularities were caused by mechanical effects of pulsed plasma. The hardness of the analyzed C80U steel varied significantly between areas of measurement. In selected measurement points, hardness values reached 3200–3100 HV, 1800 HV and 400–300 HV. XRD and SAD investigation revealed in microstructure of processed steel martensite, partially dissolved cementite (FeCrMn)3C and small amount of retained austenite. The microstructure revealed by TEM indicates that in areas with greater hardness there were higher dislocations and twins density. Hardness test with a multiple load cycle with increasing load from 0.5 N to 20 N showed that shock waves formed as a result of plasma plume propagation interacting with the melted steel, thus contributing to the strain hardening of processed steel and providing an occurrence of the biggest residual stresses near the surface and reducing them with the depth of melted steel. Impact stress generated by extending plasma also facilitated the phase transformation of austenite and thus reduced the amount of retained austenite
Survey of Radio Navigation Systems
- Przemysław Falkowski-Gilski
- Jacek Stefański
2015 Pełny tekst International Journal of Electronics and Telecommunications
At present, there is a growing demand for radio navigation systems, ranging from pedestrian navigation to consumer behavior analysis. These systems have been successfully used in many applications and have become very popular in recent years. In this paper we present a review of selected wireless positioning solutions operating in both indoor and outdoor environments. We describe different positioning techniques, methods, systems, as well as information processing mechanisms.
Survey on Applications of Multimedia Technology to Examine Impact of Roadside Advertising on Drivers
- Andrzej Czyżewski
- Adam Korzeniewski
- Piotr Odya
- Piotr Szczuko
- Bożena Kostek
2015
The correct location of ads, both static and moving, in close proximity of the roadway is an issue of high significance in the context of road safety. This publication aims to provide support in solving these issues by presenting a range of options for the implementation of extensive, multi-faceted research, using modern technology to allow an objective assessment of the risks arising from the presence of advertising spots in the roadway. The chosen research tools include the drivers’ reaction tracking systems based on the use of advanced multimedia technology. These systems may be integrated in the actual vehicle, allowing for performing the tests in real-life conditions or as part of an extended driving simulator. In addition, a part of the proposed approaches to researching the problem is to check drivers’ opinion using questionnaires and to analyze the traffic accidents taking place in close proximity to road advertising.
SURVEY SIMULATOR – PLATFORMA VR DLA EDUKACJI W PRZEMYŚLE MORSKIM
- Cezary Żrodowski
2015 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Artykuł przedstawia założenia, architekturę i główne funkcje programu DNVGL Survey Simulator. Program, bazujący na wizualizacji 3D okrętów i platform wiertniczych, został stworzony w celu wspomagania profesjonalnego szkolenia załóg pływających. Realizuje on model kształcenia w znacznej mierze odmienny od akademickiego, skoncentrowany przede wszystkim na problemach praktycznych i procedurach obowiązujących w przemyśle. Przedstawione zostały również pierwsze wyniki jego implementacji w procesie nauczania na Wydziale Oceanotechniki i Okrętownictwa Politechniki Gdańskiej.
Sustainble Court (Sąd przyszłości) a budowa kapitału społecznego
- Sylwia Morawska
- Przemysław Banasik
2015
Wzrost zaufania do wymiaru sprawiedliwości może wpłynąć pozytywnie na relacje z interesariuszami zewnętrznymi. Budowa sądu przyszłości – sądu odpowiedzialnego (Responsibility Court) rozwijającego komunikację ze wszystkimi interesariuszami może nastąpić poprzez doskonalenie komunikacji zewnętrznej. Komunikacja jest jednym z kluczowych obszarów zarządzania wiedzą. Komunikacja rozumiana szeroko obejmuje oprócz komunikacji zewnętrznej, stanowiącej doskonale źródło wiedzy o funkcjonowaniu sądu:  komunikację wewnętrzną (m. in. z takimi interesariuszami, jak pracownicy),  komunikację, która nie sprowadza się jedynie do wymiany informacji, ale ma na celu przekazywanie wiedzy – w tym uczenie się organizacji,  komunikację międzyludzką, ale również komunikację na styku system informacyjny (w tym przede wszystkim IT) – człowiek. W niniejszym rozdziale zaprezentowano także „dobre praktyki mające na celu budowę sądu przyszłości – sądu odpowiedzialnego (Responsibility Court). Rozdział odpowiada na trzy podstawowe pytania: (1) po co, dlaczego?, (2) na jakiej zasadzie? oraz jak? prowadzić działania mające na celu wzrost wartości społecznej (pozytywnej zmiany społecznej) organizacji wymiaru sprawiedliwości dostosowanej do potrzeb jej interesariuszy. Pytanie pierwsze należy do porządku aksjologicznego, normatywnego. Drugie pytanie przynależy do systemowego, instytucjonalnego. Pytanie trzecie dotyczy instrumentalnego, operacyjnego wymiaru działania. W rozdziale wykorzystano następujące metody badawcze: 1. Studia literaturowe 2. Case study.
SVC and power transformers controllers coordination
- Robert Małkowski
- Robert Kowalak
- Jacek Klucznik
2015
The use of shunt compensators such as FACTS (for example SVC) in power systems gives possibility of fast and flexible control of voltage or reactive power. An efficient cooperation between a transformer and compensator connected to busbars, or transformer’s tertiary winding, requires a proper coordination of controls. The article contains theoretical considerations and simulation results which indicate that such co-ordination is necessary. The principal recommendations for the transformer and compensator controllers settings and the co-ordination between control systems have been presented.
Sympathetic Activation Does Not Affect the Cardiac and Respiratory Contribution to the Relationship between Blood Pressure and Pial Artery Pulsation Oscillations in Healthy Subjects
- Pawel Winklewski
- Yurii Tkachenko
- Kamila Mazur
- Jacek Kot
- Marcin Gruszecki
- Wojciech Gumiński
- Krzysztof Czuszyński
- Jerzy Wtorek
- Andrzej Frydrychowski
2015 Pełny tekst PLOS ONE
Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) and subarachnoid width (sas-TQ) in humans, we assessed the influence of sympathetic activation on the cardiac and respiratory contribution to blood pressure (BP) cc-TQ oscillations in healthy subjects. The pial artery and subarachnoid width response to handgrip (HGT) and cold test (CT) were studied in 20 healthy subjects. The cc-TQ and sas-TQ were measured using NIR-T/BSS; cerebral blood flow velocity (CBFV) was measured using Doppler ultrasound of the left internal carotid artery; heart rate (HR) and beat-to-beat mean BP were recorded using a continuous finger-pulse photoplethysmography; respiratory rate (RR), minute ventilation (MV), end-tidal CO2 (EtCO2) and end-tidal O2 (EtO2) were measured using a metabolic and spirometry module of the medical monitoring system. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations. HGT evoked an increase in BP (+15.9%; P<0.001), HR (14.7; P<0.001), SaO2 (+0.5; P<0.001) EtO2 (+2.1; P<0.05) RR (+9.2%; P = 0.05) and MV (+15.5%; P<0.001), while sas-TQ was diminished (-8.12%; P<0.001), and a clear trend toward cc-TQ decline was observed (-11.0%; NS). CBFV (+2.9%; NS) and EtCO2 (-0.7; NS) did not change during HGT. CT evoked an increase in BP (+7.4%; P<0.001), sas-TQ (+3.5%; P<0.05) and SaO2(+0.3%; P<0.05). HR (+2.3%; NS), CBFV (+2.0%; NS), EtO2 (-0.7%; NS) and EtCO2 (+0.9%; NS) remained unchanged. A trend toward decreased cc-TQ was observed (-5.1%; NS). The sas-TQ response was biphasic with elevation during the first 40 seconds (+8.8% vs. baseline; P<0.001) and subsequent decline (+4.1% vs. baseline; P<0.05). No change with respect to wavelet coherence and wavelet phase coherence was found between the BP and cc-TQ oscillations. Short sympathetic activation does not affect the cardiac and respiratory contribution to the relationship between BP—cc-TQ oscillations. HGT and CT display divergent effects on the width of the subarachnoid space, an indirect marker of changes in intracranial pressure.
SYMPTOMY ASYMETRII WIRNIKA W UKŁADACH NAPĘDOWYCH O ZMIENNEJ PRĘDKOŚCI KĄTOWEJ WAŁU Z SILNIKIEM KLATKOWYM
- Piotr Kołodziejek
2015 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
W artykule przedstawiono badania eksperymentalnesymptomów asymetrii wirnika silnika indukcyjnego klatkowego wynikającej z uszkodzenia. Uwzględniono współczesne struktury układów sterowania napędami o zmiennej prędkości kątowej wału, sterowania z pomiarem prędkości kątowej wału oraz sterowaniabezczujnikowego. Wyniki przeprowadzonych badań znajdują zastosowanie w diagnostyce układu napędowego. Wybór sygnału diagnostycznego istotnie wpływa na możliwości detekcji uszkodzenia we wczesnej fazie rozwoju lub przy ograniczonymobciążeniu silnika. Przedstawiono badania wrażliwości zmiennych stanu oraz zmiennych sterujących na asymetrię wirnika.
Symulacja obróbki na bazie pliku CLData za pomocą oprogramowania Matlab
- Adam Barylski
- Norbert Piotrowski
2015 Pełny tekst Mechanik
W artykule przedstawiono niekonwencjonalne podejście w modelowaniu obrabiarek. Obrabiarkę, którą zamodelowano, jest 5-osiowa frezarka ze stołem wychylno-obrotowym. Poza opracowanymi równaniami opisującymi ruchy poszczególnych osi, utworzono model graficzny w oprogramowaniu Matlab. Program umożliwia również wczytanie ścieżek obróbkowych wygenerowanych w systemie CAM. Przeprowadzono symulację przykładowych ścieżek i opisano inne możliwości, jakie umożliwia symulacja obróbki w Matlabie.
SYMULACJA PRACY GRUNTOWEGO WYMIENNIKA CIEPŁA - UŻYCIE METOD NUMERYCZNYCH
- Tomasz Muszyński
- Rafał Andrzejczyk
- Tomasz Mania
2015
Artykuł poświęcony jest zagadnieniu wykorzystania symulacji numerycznych do projektowania GWC( Gruntowego Wymiennika Ciepła). W artykule opisano różne rodzaje gruntowych wymienników ciepła. Aparaty te używane są do wykorzystania pojemności cieplnej gleby w połączeniu z pompą ciepła dla zwiększenia ich skuteczności. Jedno, dwu i trój wymiarowe modele obliczeniowe procesu wymiany ciepła znaleźć można w literaturze. Modele symulacyjne mogą być z powodzeniem stosowane do określenia wymiarów i przewidywania wydajności cieplnej gruntowych wymienników ciepła. Systemy te zwykle dostarczają więcej ciepła i energii od energii pierwotnej, zużytej do zasilania wentylatorów lub pomp. Według przedstawionych w niniejszym opracowaniu badań, na dostatecznej głębokości, temperatura podłoża jest zawsze wyższa od powietrza na zewnątrz w zimie i niższa w lecie. Ta różnica temperatur może być wykorzystana przez GWC do ogrzewania zimą i chłodzenia latem.
Symulacja pracy przesuwnika fazowego w sieci elektroenergetycznej przy połączeniu transformatora szeregowego w gwiazdę
- Marcin Sarnicki
- Bartosz Tarakan
- Krzysztof Tarakan
- Ryszard Zajczyk
2015 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Poniższy artykuł prezentuje sposób regulacji mocy czynnej i biernej za pomocą przesuwnika fazowego, którego uzwojenie transformatora dodawczego (szeregowego) jest połączone w gwiazdę. W artykule pokazano regulację mocy czynnej i biernej na przykładzie wybranego systemu elektroenergetycznego. Omawiany przesuwnik fazowy reguluje jednocześnie przepływem mocy czynnej i biernej w danym systemie elektroenergetycznym.