2018 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2018

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The effect of high molecular weight bio-based diamine derivative of dimerized fatty acids obtained from vegetable oils on the structure, morphology and selected properties of poly(ether-urethane-urea)s
- Marcin Włoch
- Janusz Datta
- Kamila Błażek
2018 Pełny tekst JOURNAL OF POLYMERS AND THE ENVIRONMENT
In this work, the effect of the high molecular weight bio-based diamine on the chemical structure and selected properties of poly(ether-urethane-urea)s has been investigated. The ether-urethane prepolymer was cured using 1,4-butanediol and/or bio-based diamine. Mentioned chain extenders were used separately or in the mixture, and their different molecular weight and chemical structure resulted in obtaining materials with diversified mechanical performence. The presence of specific chemical groups (i.e. urethane and urea groups) was confirmed by FTIR method. For the synthesized poly(ether-urethane-urea)s morphology and fracture mechanism, thermo-mechanical properties and mechanical properties were determined and discussed. Results confirmed that bio-based diamine acts as soft segments, and this is connected with changing of mechanical and thermo-mechanical properties of prepared partially bio-based poly(etherurethane-urea)s. The increasing content of bio-based diamine resulted in increasing of tensile modulus and decreasing of tensile strength and elongation at break, and this is resulted from chemical structure of biobaseddiamine (i.e. presence of aliphatic side chains).
The Effect of Long Term Service at Elevated Temperatures on Microstructure Degradation of Austenitic Reformer Tubes
- Jerzy Łabanowski
- Mateusz Jurkowski
- Michał Landowski
2018 Pełny tekst Advances in Materials Science
The paper analyses the relationship between an increase of the inner diameter of tubes made of Manaurite XM cast steel and transformations occurring in their microstructure due to long-lasting operation in methane reformer. Examinations included metallographic analysis with light microscope (LM), scanning electron microscope (SEM) and microanalysis of the chemical composition of precipitates (EDX). It was indicated that there is a relationship between the microstructure degradation ratio, morphology of the precipitates and an increase of the inner diameter of the tubes.
The effect of macro polymer fibres length and content on the fibre reinforced concrete
- Aleksandra Kuryłowicz-Cudowska
- Marzena Kurpińska
2018 Pełny tekst MATEC Web of Conferences
The paper presents studies of a ready-mix concrete containing polymer fibres of three different lengths: 24, 38 and 54 mm. The performed tests allowed to determine the effect of fibre volume fraction and length on the concrete strength. The basic parameters of concrete mixture (consistency, air content and bulk density) were identified. Fibre reinforced concrete belongs to a group of composite materials. The polymer fibres are applied in the concrete in structures where the reduction of shrinkage cracking as well as corrosion resistance and fire temperatures are required. It is widely known, that the cracking behaviour of concrete structures depends on flexural tensile strength of concrete. The addition of fibres significantly improves the tensile strength. The experimental study, including axial compressive strength and center-point loading flexural tensile strength, was carried out. The scope of the research was also expanded by the usage of a scanning microscope. The test results showed the effect of fibre length and fibre combinations on mechanical properties of concrete. The effect of the research is to formulate guidelines due to the quantity of macro polymer fibres. In general, appropriate fibre content brings a beneficial effect e.g. improves better workability of a concrete
THE EFFECT OF NOTCH DEPTH ON CTOD VALUES IN FRACTURE TESTS OF STRUCTURAL STEEL ELEMENTS
- Jakub Kowalski
- Janusz Kozak
2018 Pełny tekst Polish Maritime Research
In elements of steel structures working at low temperatures, there is a risk of appearance of brittle fracture. This risk is reduced through the use of certified materials having guaranteed strength at a given temperature. A method which is most frequently used to determine brittle fracture toughness is the Charpy impact test, preformed for a given temperature. For offshore structures intended to work in the arctic climat e, the certifying institutions more and more often require Crack Tip Opening Displacement (CTOD) tests instead of conventional impact tests, especially for steel and welded joints of more than 40 mm in thickness in the case of high-strength steel, and more than 50 mm for the remaining steels. The geometry of specimens and the test procedure are standardised; however, these standards provide some margin for specimen notch depth. The paper analyses the effect of notch depth difference, within the range permitted by the standards, on the recorded CTOD values of a given material. The analysis was performed via numerical modelling of destruction of specimens with different notch geometries and further verification of the obtained numerical results in laboratory tests. The calculations were carried out at the Academic Computer Centre in Gdansk.
The effect of numerical 2D and 3D FEM element modelling on strain and stress distributions at laser weld notches in steel sandwich type panels
- Karol Niklas
- Janusz Kozak
2018 Pełny tekst Polish Maritime Research
Like other means of transport, merchant ships face the problem of increasing requirements concerning the environment protection, which, among other issues, implies the reduction of fuel consumption by the ship. Here, the conventional approach which consists in making use of higher strength steels to decrease the mass of the ship hull can be complemented by the use of new steel structures of sandwich panel type. However, the lack of knowledge and experience concerning, among other issues, fatigue strength assessment of thin-walled sandwich structures makes their use limited. Untypical welds imply the need for individual approach to the fatigue analysis. The article presents the effect of numerical FEM modelling with the aid of two-dimensional (2D) and three-dimensional (3D) elements on the results of strain and stress distributions in the areas of toe and root notches of the analysed laser weld. The presented results of computer simulation reveal that modelling of strain and stress states in 2D (instead of full 3D) affects only the results in close vicinity of the notch, and the observed differences rapidly disappear at a distance of 0.05 mm from the bottom of the notch. The obtained results confirm the possibility of use of numerically effective 2D strain and stress state models for analysing the fatigue strength of laser weld according to local approach.
The Effect of Oxygenated Diesel-N-Butanol Fuel Blends on Combustion, Performance, and Exhaust Emissions of a Turbocharged CRDI Diesel Engine
- Gvidonas Labeckas
- Stasys Slavinskas
- Jacek Rudnicki
- Ryszard Zadrąg
2018 Pełny tekst Polish Maritime Research
The article deals with the effects made by using various n-butanol-diesel fuel blends on the combustion history, engine performance and exhaust emissions of a turbocharged four-stroke, four-cylinder, CRDI 1154HP (85 kW) diesel engine. At first, load characteristics were taken when running an engine with normal diesel fuel (DF) to have ‘baseline’ parameters at the two ranges of speed of 1800 and 2500 rpm. Four a fossil diesel (class 1) and normal butanol (n-butanol) fuel blends possessing 1 wt%, 2 wt%, 3 wt%, and 4 wt% (by mass) of n-butanol-bound oxygen fractions were prepared by pouring 4.65 wt% (BD1), 9.30 wt% (BD2), 13.95 wt% (BD3), and 18.65 wt% (BD4) n-butanol to diesel fuel. Then, load characteristics were taken when an engine with n-butanol-oxygenated fuel blends at the same speeds. Analysis of the changes occurred in the autoignition delay, combustion history, the cycle-to-cycle variation, engine efficiency, smoke, and exhaust emissions NOx, CO, THC obtained with purposely designed fuel blends was performed on comparative bases with the corresponding values measured with ‘baseline’ diesel fuel to reveal the potential developing trends.
The effect of reduced pressure on carbon dioxide flow boiling heat transfer in minichannels
- Dariusz Mikielewicz
- Blanka Jakubowska
2018
. In the paper presented are the results of the study on the effect of reduced pressure on flow boiling heat transfer data in minichannels as well as conventional ones. That effect renders that most of heat transfer correlations fail to return appropriate results of predictions. Mostly they have been developed for the reduced pressures from the range 0.1-0.3. The special correction has been postulated to the in-house model of flow boiling and condensation which modifies the two-phase flow multiplier as well as the temperature gradient in pool boiling. Four two-phase flow multiplier models were tested for this purpose, i.e. due to Friedel, Tran, Müller-Steinhagen and Heck and finally its in-house modification for applicability to minichannels. The model has been tested against a large selection of experimental data collected from various researchers to investigate the sensitivity of the in-house developed model. The collected experimental data came from various studies from literature and were conducted for the full range of quality variation and a wide range of mass velocity and saturation temperatures. In the work are presented the results of calculations obtained using the in-house developed semi empirical model on selected experimental flow boiling data related to carbon dioxide.
The effect of road restraint systems on the level of road safety - Polish experience
- Marcin Budzyński
- Kazimierz Jamroz
- Łukasz Jeliński
2018
Roadside accidents happen when a vehicle runs off the road. The majority of these accidents are very severe because leaving the road is usually followed by hitting a solid obstacle (tree, pole, support, culvert front wall, barrier). Roadsides are some of the most important issues of road safety. They have been studied for years to identify roadside hazards and the effectiveness of road safety measures such as restraint systems. While restraint systems prevent crashes into obstacles or running off the road down steep slopes, they are obstacles themselves. If wrongly designed and located, restraints may pose a serious risk to the safety of road users. Examples of safety barrier models were analysed to understand how barriers change safety. It was found that the models differ and use different methodologies and data. In building a new analytical tool, the models’ differentiating factors were combined to create a comprehensive model to match the Polish conditions. Fieldwork focussed on sections outside built-up areas, i.e. on national roads of the total length of app. 3,000 km. The data were inventoried separately for the left and right edge of the road and for the central reservation. Potential roadside hazards were identified (e.g. trees, slopes, utility poles, engineering structures) as well as the type of cross-section and existing types of safety barriers (concrete, steel, wire rope). Using the data collected, models of road safety measures were developed. By combining the effect of the roadside and safety measures, the models will help to build tools for road network management at the operational level (concrete locations on the road network) and select the right types of restraint systems and design the clearance zone.
The effectiveness of polymer adhesive in reduction of vibrations of structural members
- Natalia Lasowicz
- Arkadiusz Kwiecień
- Robert Jankowski
2018 Pełny tekst MATEC Web of Conferences
In this paper, the idea of using polymer adhesive as a damping layer is proposed. An experimental study of two aluminium cantilevered beams has been conducted. One of them presents a plain cantilevered beam, while the second one considers two aluminium beams bonded with a polymer adhesive of different thickness (0,5; 1,2; 1,75; 3,1 and 5 mm). The polymer adhesive considered in the study is a specially designed flexible two-component grout, which has high damping properties. The aim of the study is to determine dynamic parameters, such as natural frequencies and damping ratios of both beams, based on the tests in which analyzed elements have been induced to vibrations by a modal hammer. The behaviour of the beams under different additional weight, installed at the end of elements, has been studied. The results of the study clearly show that the response of the composite aluminium beam with polymer adhesive inside is substantially different then the response of the plain beam. The application of polymer adhesive leads to significant increase in structural damping. Based on the results, the method of using the polymer adhesive can be considered as an effective one in reduction of structural vibrations.
The effects of offshoring to low-wage countries on domestic wages: a worldwide industrial analysis
- Joanna Wolszczak-Derlacz
- Aleksandra Parteka
2018 Pełny tekst Empirica
This paper extends the literature on the implications of offshoring for labour markets by investigating its effect on the wages of different skill groups in a broad global context. The analysis draws on input–output data from the WIOD project, and in the panel analysed (13 manufacturing industries, 40 countries, 1995–2009) we account for up to 96 % of the international trade in manufacturing inputs. Being particularly interested in the wage effects of offshoring to low-wage countries (LWC), we use precise LWC classifications (varying across industries and time) to decompose overall offshoring by source country. We use a decomposition of the conventional offshoring measure in order to capture its pure international component, which is further instrumented using a gravity-based strategy. According to the estimation results, the negative impact of offshoring on wages mainly concerns low and medium skilled workers. However, in terms of magnitude, the downward pressure on domestic wages exhibited by offshoring to LWC is relatively small.
The effects of perceived risk, brand value, and brand trust on eWOM
- Magdalena Brzozowska-Woś
2018 Pełny tekst Handel Wewnętrzny
Unrestricted access to the Internet, mobile devices, social applications and offering shopping comment options via online stores and platforms, encourages customers to generate online reviews about brands. That is why it became important to learn about the factors that motivate customers to create electronic word of mouth (eWOM). The survey aimed to check if there are links between perceived brand value, perceived risk, brand trust and consumers' willingness to express opinions online about products bought online. Structural equation modelling (SEM) was applied to analyse the data from the study (340 respondents). Five of the six hypotheses were confirmed. The direct impact of perceived brand value on generating eWOM has not been established. Perceived product value has a more significant effect on brand trust than perceived risk. The adverse effect of perceived risk on the perceived brand value by consumers was also confirmed. It also turned out that trust in the brand has a more significant effect on the significance of eWOM than the perceived risk.
The efficiency and technological reliability of biogenic compounds removal during long-term operation of a one-stage subsurface horizontal flow constructed wetland
- Krzysztof Jóźwiakowski
- Piotr Bugajski
- Karolina Kurek
- Maria De
- Maria Almeida
- Tadeusz Siwiec
- Gabriel Borowski
- Wojciech Czekała
- Jacek Dach
- Magdalena Gajewska
2018 SEPARATION AND PURIFICATION TECHNOLOGY
The paper presents the results of a study of the efficiency and technological reliability of total nitrogen and total phosphorus removal during long term operation of a one-stage constructed wetland system with subsurface horizontal wastewater flow. The flow rate of the wastewater treatment plant was 1.2m3/d during the research period. Physical and chemical analyses of raw wastewater and treated effluent were carried out in the years 1997–2010 (14 years). During this study period, 56 series of analyses were performed and 112 wastewater samples were collected. It was observed that the average efficiency of total nitrogen and total phosphorus removal amounted to 51% and 73%, respectively. The technological reliability, determined by means of the Weibull reliability method, was 45% for total nitrogen removal and 48% in the case of total phosphorus removal. Total nitrogen and total phosphorus concentrations in the treated wastewater did not exceed the permissible values in 39.3% and 37.5% of cases, respectively. A negative correlation was found between the sorption capacity of the soil-plant filter for the removal of total phosphorus and the time of plant operation. The efficiency of total nitrogen removal was stable over time.
The Emission and Combustion Characteristics of Marine Diesel Engine with Extreme Throttled of Air or Exhaust Ducts
- Jerzy Kowalski
2018 Pełny tekst New Trends in Production Engineering
Presented paper shows the results of the laboratory tests on the relationship between the extreme throttling of both air intake duct and exhaust gas duct and gaseous emission from the marine engine. The object of research is a laboratory, 4-stroke, DI diesel engine, operated at loads from 50 kW to 250 kW at a constant speed equal to 750 rpm. During the laboratory tests the thermodynamic and exhaust gas emission characteristics of the engine were measured with technical condition recognized as "working properly" and with simulated throttling of both air intake duct and exhaust gas duct. Air intake duct throttling by 60% causes visible changes at both gas temperature and pressure behind the intercooler. The study results show significant changes of NOx and CO2 emission for considered air intake duct throttling. The best indicator of exhaust gas duct throttling among considered thermodynamic parameters of the engine is mean in-cylinder pressure. In the case of measuring the composition of exhaust gas, the throttling of the exhaust gas duct causes visible changes in CO2 and NOx emission. The conclusion is that the results of measurements of the composition of the exhaust gas may contain valuable diagnostic information about the technical condition of air intake and exhaust gas duct of the marine engine
The energy consumption during the birch tree sap concentration process using the reverse osmosis system
- Jarosław Wawer
- Bilek Maciej
- Sosnowski Stanisław
2018 Econtechmod. An International Quarterly Journal on Economics of Technology and Modelling Processes
Birch tree sap was concentrated by mens of the reversed osmosis technique. The energy consumption in a small-scale pilot apparatus was estimated. The threshold value for the water removal above which the specific energy consumption significantly increased was identified. Below the threshold value the reversed osmosis had low energy demand and could be an attractive method for the production of birch tree sap-based beverages.
The entrepreneurship of host cities of the Olympic Games – Between success and social destruction
- Jarosław Ziętarski
- Jedel Joanna
2018 Pełny tekst Baltic Journal of Health and Physical Activity
Many publications focus on the deficit nature of the Olympic Games organisation, when considered from the point of view of host cities – organisers of such events. However, does such an event actually affect the region and the host country in a positive way? The presented article aims at the assessment of the organisation of mass sports events, such as the Olympic Games, taking into consideration entrepreneurial activities which can be defined in terms of a productive, destructive or socially destructive category. In order to determine the relevant types of entrepreneurship, the authors refer to well-established definitions (in the case of productive and socially destructive types) and to their own, original definition of destructive entrepreneurship.
THE EUROPEAN UNION AND JAPAN TOWARDS STRATEGIC PARTNERSHIP AGREEMENT AND ECONOMIC PARTNERSHIP AGREEMENT
- Izabela Borucińska
2018 Pełny tekst Regional Formation and Development Studies
This study aims to reveal the evolution of EU-Japan relations towards comprehensive and fully formalized strategic partnership, the main determinants of that process, as well the importance of the political and economic alliance. In the evolution of EU-Japan relations, there were identified four stages - 1960-1990, 1991-2000, 2001-2010, 2011-2018 - which had led up to strategic partnership regulated by the framework political and economic agreements. Strategic Partnership Agreement and Economic Partnership Agreement might enhance the regional and global influence of the EU and Japan in future.
The Experimental Determination of Bearings Dynamic Coefficients in a Wide Range of Rotational Speeds, Taking into Account the Resonance and Hydrodynamic Instability
- Łukasz Breńkacz
- Grzegorz Żywica
- Marta Drosińska-Komor
- Natalia Szewczuk-Krypa
2018
Methods for the experimental determination of dynamic coefficients are commonly used for the analysis of various types of bearings, including hydrodynamic, aerodynamic and foil bearings. There are currently several algorithms that allow estimating bearing dynamic coefficients. Such algorithms usually use various excitation techniques applied to rotor–bearings systems. So far only a small number of scientific publications show how calculated dynamic coefficients of bearings change as speed rises. In the literature, there are no computation results that demonstrate changes in these coefficients either in a broad range of speeds (that would cover resonant speeds) or at speeds at which a phenomenon of hydrodynamic instability can be observed. This article fills the literature gap in question. For calculation purposes, the impulse response method based on an in-house algorithm (with a linear approximation using the least squares method) was applied. On its basis, the stiffness, damping and mass coefficients of a rotor–bearings system were calculated. It turns out that some of the obtained values of damping coefficients are negative at the resonant speed. Moreover, if the values are calculated at a speed at which the hydrodynamic instability phenomenon is present they are accompanied by considerably higher standard deviations. On the basis of our computation results and the literature review, capabilities and limitations of the method used for the experimental identification of dynamic coefficients of hydrodynamic bearings were discussed
The forming and emission of high power electromagnetic pulses
- Kazimierz Jakubiuk
- Daniel Kowalak
- Mikołaj Nowak
2018
An impulse energy source, a power conditioning system and an electromagnetic field emitter are essential to generate an electromagnetic field pulse (EMFP) with a specific frequency bandwidth. Selected simulation results for a power conditioning system consisting of a fuse opening switch and a paraboloidal electromagnetic emitter have been presented in this article. The synthetic system examined in the simulation is powered by an impulse capacitor instead of a flux compression generator (FCG) used in practice. The obtained results confirm that pulse generation and emission of high-power EMFP is possible.
The homometallic warwickite V 2 OBO 3
- Elizabeth M. Carnicom
- Karolina Górnicka
- Tomasz Klimczuk
- Robert J. Cava
2018 JOURNAL OF SOLID STATE CHEMISTRY
The synthesis, structure and elementary magnetic characterization of the homometallic warwickite V2OBO3 are reported. The material adopts the orthorhombic warwickite structure type at room temperature, space group Pnma (No. 62) with lattice parameters a = 9.2317(1) Å, b = 3.1172(1) Å, and c = 9.5313(1) Å. Temperature-dependent magnetic susceptibility, electrical resistivity, and specific heat measurements show anomalies near 35 K, between 135 K and 150 K, and near 260 K, with the transition at ~ 35 K likely to a ferrimagnetic state.
The Imaging of Gdansk Bay Seabed by Using Side Sonar
- Grażyna Grelowska
- Eugeniusz Kozaczka
- Dominika Witos-Okrasińska
- Wojciech Szymczak
2018 Pełny tekst Polish Maritime Research
This paper is mainly aimed at presentation of an impact of environmental conditions on imaging accuracy by using hydro-acoustic systems in waters of a high non-uniformity of spatial distribution of hydrological parameters. Impact of refraction on erroneous estimation of range, in case of wave radiation into water under a large angle, like in side sonars or multi-beam echo-sounders, is especially important. In this paper seasonal changes in sound speed and its impact on acoustic beam refraction is discussed. And, examples which illustrate errors in determination of side sonar range occurred during last investigations carried out in Gdansk Bay waters are presented.