2019 - Repozytorium publikacji - Politechnika Gdańska

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Examination of fresh water chemistry in maritime Antarctica during austral summer 2017
- Małgorzata Szopińska
- Ruman Marek
- Robert Józef Bialik
- Żaneta Polkowska
2019 Pełny tekst AIP Conference Proceedings
Due to the fact that Antarctica is one of the least polluted places on Earth, it is a perfect place to observe the spread of global pollution. Therefore, research conducted on this continent is important due to the possibility of investigating the type of pollution and their way of transport. This work considers presence of organic contaminants in Maritime Antarctica in unexplored until now, Lions Rump headland. Qualitative and quantitative analysis of samples were carried out in order to determine the content of analytes such as polycyclic aromatic hydrocarbons (PAHs). Among all determined PAHs in water samples the highest concentrations was observed for naphthalene and anthracene, which is the result of their higher volatility in comparison to the High Molecular Weight PAHs. The presence of PAHs in the water environment may constitute potential negative effect on Antarctic ecosystem and it should be investigated in detail. Moreover, possibility of undertaking various actions reducing contaminants emission are also very important. We hope that improved fossil fuel economy, and not only on the local scale, would help reduce PAH levels in Maritime Antarctica.
Examining Ownership Equity as a Psychological Factor on Tourism Business Failure Forecasting
- Tomasz Korol
- Anastasia Spyridou
2019 Pełny tekst Frontiers in Psychology
This paper examines ownership equity as a predictor of future business failure within the tourism and hospitality sectors. The main goals of this study were to examine which ratios are the most important for a tourism business failure forecasting model and how significant is the “total percentage of equity ownership by company directors” ratio compared with other ratios associated with the probability of bankruptcy. A stepwise weight assessment ratio analysis (SWARA) was applied, and 12 tourism bankruptcy experts evaluated key ratios. Total percentage of equity ownership by company directors is considered a psychological factor, and it was identified as the fourth most important ratio for a business failure forecasting model. Academicians and practitioners can use the findings of this study whenever developing a forecasting model for tourism and hospitality enterprises.
Exchange-Traded Funds in Europe
- Adam Marszk
- Ewa Lechman
2019
Exchange-Traded Funds in Europe provides a single point of reference on a diverse set of regional ETF markets, illuminating the roles ETFs can play in risk mitigation and speculation. Combining empirical data with models and case studies, the authors use diffusion models and panel/country-specific regressions—as well as graphical and descriptive analyses— to show how ETFs are more than conventional, passive investments. With new insights on how ETFs can improve market efficiency and how investors can benefit when using them as investment tools, this book reveals the complexity of the world’s second largest ETF market and the ways that ETFs are transforming it.
Excitation of Non-Wave Modes by Sound of Arbitrary Frequency in a Chemically Reacting Gas
- Anna Perelomova
2019 Pełny tekst ACTA ACUSTICA UNITED WITH ACUSTICA
The nonlinear phenomena in the field of high intensity sound propagating in a gas with a chemical reaction, are considered. A chemical reaction of A → B type is followed by dispersion and attenuation of sound which may be atypical during irreversible thermodynamic processes under some conditions. The first and second order derivatives of heat produced in the chemical reaction evaluated at the equilibrium temperature, density and mass fraction of reagent A, are taken into account. The instantaneous equations are derived which govern dynamics of perturbations in non-acoustic modes, and conclusions of the efficiency of their nonlinear excitation by sound are drawn. The advantage of this study is accurate description of dispersion. Acoustic perturbations of any characteristic duration as compared to the duration of chemical reaction are considered, along with periodic, aperiodic perturbations and impulses. The conclusions concern also acoustically active gases.
Excited state properties of a series of molecular photocatalysts investigated by time dependent density functional theory.
- Miłosz Martynow
- Kupfer Stephan
- Sven Rau
- Julien Guthmuller
2019 Pełny tekst PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Time dependent density functional theory calculations are applied on a series of molecular photocatalysts of the type [(tbbpy)2M1(tpphz)M2X2]2+ (M1 = Ru, Os; M2 = Pd, Pt; X = Cl, I) in order to provide information concerning the photochemistry occurring upon excitation of the compounds in the visible region. To this aim, the energies, oscillator strengths and orbital characters of the singlet and triplet excited states are investigated. The structural modifications of the complexes have a strong impact on the excited states properties. In particular, it is found that the main differences concern the energies of the charge-separated and metal-centered states. The analysis of these differences provides general trends for the efficiency of population transfers between the states, particularly regarding the charge separation and electron recombination processes.
Experience based decisional DNA to support smart product design
- Muhammad Ahmed
- Cesar Sanin
- Syed Imran Shafiq
- Edward Szczerbicki
2019 JOURNAL OF INTELLIGENT & FUZZY SYSTEMS
This paper presents the idea of Smart Virtual Product Development (SVPD) system to support product design. The foundations of the system are based upon smart knowledge management techniques called Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA). It enhances the industrial product development process by using the previous experiential knowledge gathered from the formal decisional activities. This experiential knowledge is collected from the group of similar products having some common functions and features. The developed system comprises of three modules: design knowledge management (DKM), manufacturing capability analysis and process planning (MCAPP), and product inspection planning (PIP). The working of design knowledge management module is presented in this study and is validated by using an industrial case study, which suggests that it is capable of capturing and reusing the required design knowledge for material selection process. The developed system has the capability to facilitate decision making and mistake proofing during early stages of product design. It can be beneficial for small and medium enterprises (SMEs) involved in product development.
Experience based knowledge representation for Internet of Things and Cyber Physical Systems with case studies
- Cesar Sanin
- Zhang Haoxi
- Imran Shafiq
- Md Waris
- Caterine Silva de Oliveira
- Edward Szczerbicki
2019 Future Generation Computer Systems-The International Journal of Grid Computing-Theory Methods and Applications
Cyber Physical Systems and Internet of Things have grown significant attention from industry and academia during the past decade. The main reason behind this interest is the capabilities of such technologies to revolutionize human life since they appear as seamlessly integrating classical networks, networked objects and people to create more efficient environments. However, enhancing these technologies with intelligent skills becomes an even more interesting and enticing scenario. In this paper, we propose and illustrate through a number of case studies how Decisional DNA, a multi-domain knowledge structure based on experience, can be implemented as a comprehensive embedded knowledge representation for Internet of Things and Cyber Physical Systems. Decisional DNA gathers explicit experiential knowledge based on formal decision events and uses this knowledge to support decision-making processes. The main advantages of using Decisional DNA are as follows: (i) offers a standardized form of the collected knowledge and experience, (ii) provides versatility and dynamicity of the knowledge structure, (iii) stipulates storage of day-to-day explicit experience in a single configuration, (iv) delivers transportability and shareability of the knowledge, and (v) provides predicting capabilities based on the collected experience. Consequently, test and results of the presented implementation of Decisional DNA case studies support it as a technology that can improve and be applied to the aforementioned technologies enhancing them with intelligence by predicting capabilities and facilitating knowledge engineering processes.
Experiences and Challenges in Fatality Reduction on Polish Roads
- Kazimierz Jamroz
- Marcin Budzyński
- Aleksandra Romanowska
- Joanna Żukowska
- Jacek Oskarbski
- Wojciech Kustra
2019 Pełny tekst Sustainability
According to the UN, road safety is the key to achieving sustainable development goals, yet the complexity of how road accidents happen makes this a difficult challenge leaving many countries struggling with the problem. For years, Poland has infamously been one of the EU’s top countries for road-accident fatality rates. Despite that, it has made significant progress in the last thirty years with a fatality reduction of more than 60%. A number of factors have contributed to this result: improving the socioeconomic situation, improving road safety measures, changing road user behaviour and changing national road safety programmes. This article presents Poland’s approach to road safety and, in particular, Vision Zero, adopted in 2005. Poland’s road safety changed over the years as the country learned from its successes and failures. Tools for forecasting fatalities were developed and used to identify the main factors that have helped to reduce deaths. An assessment was conducted on how Poland could implement Vision Zero until 2050 under different road safety scenarios. It was found that in order to achieve the EU’s goal for 2030, Poland must reduce fatalities to 1200. While it is an ambitious goal, it is also an important step towards zero fatalities in 2050.
Experiment-aided virtual prototyping to minimize tool-workpiece vibration during boring of large-sized structures
- Krzysztof Jan Kaliński
- Marek Galewski
- Michał Mazur
- Natalia Morawska
2019 Pełny tekst
The paper presents the author's method of solving the problems of vi-bration suppression during boring of large-sized workpieces by means of an in-novative method of adjusting the rotational speed of the boring bar. It consists in selecting the spindle speed in accordance with the results of the cutting process simulation. The method includes identification of the model of the finite element method of the boring bar. The Root Mean Square (RMS) values of the time plots and dominant values of the peaks in the frequency spectra were obtained during the boring process. The effectiveness of the proposed attempt is demonstrated by the selected mechatronic design technique, known as Experiment-Aided Vir-tual Prototyping (E-AVP). The proposed method has been verified based on the results of experimental research.
Experimental and numerical analysis of the modified TB32 crash tests of the cable barrier system
- Dawid Bruski
- Stanisław Burzyński
- Jacek Chróścielewski
- Kazimierz Jamroz
- Łukasz Pachocki
- Wojciech Witkowski
- Krzysztof Wilde
2019 ENGINEERING FAILURE ANALYSIS
Road restraint systems, including safety barriers, are one of the means used to improve road safety. Currently, they can be allowed to general use after passing the specific crash tests. However, it is always important and desirable to evaluate their performance under various realistic conditions, which can happen on the roads. In this study, the behaviour of the cable barrier system in impact conditions different than assumed by EN 1317 standard was analysed. For this purpose, a full-scale crash test was performed and on the basis of this the validation process of numerical simulations was carried out. Correctly and carefully developed numerical simulations give unique insight into the impact mechanism and allows for comprehensive understanding of barrier responses. The accuracy of the numerical models was assessed by comparing the results of the simulation with the crash test. The research showed that the analysed barrier work correctly, it contained and then properly redirected 1500 kg car back onto the road and ensured safety for the vehicle occupants at the same time.
Experimental determination of H2 mass stopping powers for low-energy electrons
- Mateusz Zawadzki
- Murtadha Khakoo
2019 Pełny tekst PHYSICAL REVIEW A
We present experimental mass stopping powers of electrons in gaseous H2 obtained with an electron time- of-flight spectrometer, for the incident electron energy range of 11 to 25 eV. In our procedure, the average energy loss is derived from conversion of the measured electron time-of-flight spectra into equivalent electron energy-loss spectra. Our present results are compared with the only available experimental measurement and with theoretical models. The measurements are a significant improvement to the available experimental data to date.
Experimental investigation into surface texture effect on journal bearings performance
- Lidia Galda
- Jaroslaw Sep
- Artur Olszewski
- Tomasz Żochowski
2019 TRIBOLOGY INTERNATIONAL
The aim of this study was to analyse the performance of journal bearings with specially created dimples on the sliding surface and operating under various conditions. The texture was created on the bearing surface that co-acted with the smooth journal; moreover, the variation of the textured surface of the journal mating with the smooth bearing was tested, and the results were compared to those obtained with the standard smooth journal bearing.
Experimental investigation of heat transfer enhancement in straight and U-bend double-pipe heat exchanger with wire insert
- Rafał Andrzejczyk
- Tomasz Muszyński
- Przemysław Kozak
2019 CHEMICAL ENGINEERING AND PROCESSING
In this paper, the possibility of heat transfer enhancement in the U-bend exchanger was presented. Experimental research has been carried out for four individual heat exchanger constructions i.e. plain tube in tube, turbulized tube in tube, plain U-bend and U-bend with turbulator. Also, heat transfer experiments for various boundary conditions were performed to obtain reference values. In case of U-bend exchanger with and without turbulator, tests were conducted based on the water-water system. The study covered a wide measuring range, i.e. Re = 800–9000 - on the jacket side, Pel = 500–1400 W (for reference) cold water temperature of 9°C and hot water of 50°C. The exchangers were made from a copper pipe with an external diameter of 10 mm and 18 mm and wall thickness of 1 mm. The helicoidal vortex generator was made from brass wire with a diameter of 2.4 mm, coil diameter 13 mm and pitch 11 mm. For these geometries, the values of pressure drop and rate of heat transfer were determined. The comparison of heat transfer efficiency was performed based on NTU-ε method. For the same thermal-flow parameters, wire inserts provide up to 280% heat transfer enhancement and 85% higher heat transfer rate.
Experimental investigations of damage evolution in concrete during bending by continuous micro-CT scanning
- Łukasz Skarżyński
- Andrzej Tejchman-Konarzewski
2019 Pełny tekst MATERIALS CHARACTERIZATION
The paper describes experimental investigation results of fracture in notched concrete beams under quasi-static three-point bending. To visualize 3D fracture in concrete under bending, an extended X-ray micro-computed tomography system was used, i.e. the tomography system SkyScan 1173 was connected to the loading machine ISTRON 5569. This combined system enabled to shot images of deforming concrete beams during a continuous deformation process, i.e. without beams' unloading for scanning. The shape, volume, size of cracks and pores were non-destructively measured during deformation. The maximum crack width during continuous micro-CT scanning was higher by about 20–30% than in the beam that was subjected to unloading for scanning.
Experimental research on marine oil-lubricated stern tube bearing
- Wojciech Litwin
2019 Pełny tekst PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
Bearings of propeller shafts are very crucial elements of the propulsion system of each of the ships. The safety of shipping depends on their durability and reliability. The new legal restrictions mean that today we are looking for environmentally friendly solutions. That is why water-lubricated bearings are becoming more and more popular. So, will oil-lubricated shaft bearings belong to the past? The bearing with a white metal bushing lubricated with mineral oil, which was subjected to experimental tests, has a number of advantages. First of all, it works in the area of full fluid friction, and in typical shipbuilding conditions it has a significant excess of hydrodynamic load capacity. Therefore, replacing mineral oil with an environmentally friendly lubricant with a similar viscosity seems to be a promising solution. Motion resistance larger than that in water-lubricated bearings compensates for the reliability and durability of this solution.
Experimental Research on the Energy Efficiency of a Parallel Hybrid Drive for an Inland Ship
- Wojciech Litwin
- Wojciech Leśniewski
- Daniel Piątek
- Karol Niklas
2019 Pełny tekst ENERGIES
The growing requirements for limiting the negative impact of all modes of transport on the natural environment mean that clean technologies are becoming more and more important. The global trend of e-mobility also applies to sea and inland water transport. This article presents the results of experimental tests carried out on a life-size, parallel diesel-electric hybrid propulsion system. The eciency of the propulsion system was analysed for two modes of operation (electric and diesel) and for dierent engine speeds and loads. Analysis of the impact of using a hybrid propulsion system on fuel consumption was carried out on a case study vessel and for six actual journeys. The use of hybrid propulsion in “zero emission” mode enables up to four times higher energy eciency when compared to a conventional drive, while reducing CO2 emissions and air pollution to zero, as well as a hundred-fold reduction in noise emissions. High flexibility in the operation of such a drive enables the use of intelligent power control technology (smart propulsion). This article shows that the use of hybrid propulsion reduces the negative impact on the environment to a minimum and allows for a significant reduction in the vessel’s operating costs.
Experimental studies on the impact of changing the pipe material on the propagation of the pressure wave during water hammer
- Natalia Krystyna Gietka
2019 Pełny tekst Acta Scientiarum Polonorum Formatio Circumiectus
Aim of the paper is to present the results studying the water hammer phenomenon in pipes made of different materials, and to show the impact of changing the type of material of the pipe on the velocity of the pressure wave during the transient flow in the pipes. In terms of research material and methods, pipes made of galvanized steel and high-density polyethylene were tested. Measurements were made using strain gauges with a high accuracy of measurement. The results of the pressure wave velocity range from 205 to 247 m/s for the polyethylene pipe, and from 426 to 1351 m/s for the steel pipe. Therefore, the change in the type of the pipe material has a significant effect on the velocity of the pressure wave during the water hammer. The value of this velocity is influenced not only by the properties of the material itself or of the liquid, but also of the length of the sections and their position relative to each other. It is evident that the velocity in the polyethylene pipe does not change significantly in relation to the situation where the pipe has constant material characteristics. The situation is radically different in the case of a steel pipe, where the velocity of the pressure wave changes along with the length of the pipe and its position relative to the tank. The lowest value of the velocity in the elastic pipe is achieved when the latter is on the valve side and is only 13.15 m long, while the highest value is reached when the 13.24 m steel pipe is located on the side of the tank.
Experimental study and comparison with predictive methods for flow boiling heat transfer coefficient of HFE7000
- Blanka Jakubowska
- Dariusz Mikielewicz
- Michał Klugmann
2019 Pełny tekst INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
This article describes an experimental study of flow boiling of HFE7000 inside a smooth vertical channel. The investigation has been carried out in a circular stainless-steel tube with an inner diameter of 2.3 mm. The data have been collected for the applied heat fluxes q ranging from 61 to 205 kW/m2, the mass flux G ranging from 214 to 1006 kg/(m2 s), the saturation temperature Tsat ranging from 30 to 54 °C and the full range of vapour quality x. The collected experimental data base amounted to 1217 experimental points. The acquired results indicated that heat flux and saturation temperature have the most significant impact on the heat transfer coefficient. The local heat transfer coefficient increases with both the heat flux and saturation temperature, while the mass flux did not exhibit a significant effect on the variation of the heat transfer coefficient. The present experimental data have been compared with various heat transfer correlations from literature including the recently enhanced in-house model. The results of comparisons indicated the superiority of the in-house model over other correlations.
Experimental Study on Dynamics of Wooden House Wall Panels with Different Thermal Isolation
- Marcin Szczepański
- Wojciech Migda
- Robert Jankowski
2019 Pełny tekst Applied Sciences-Basel
Wood frame buildings are very popular in regions that are exposed to different dynamic excitations including earthquakes. Therefore, their seismic resistance is really important in order to prevent structural damages and human losses. The aim of the present paper is to show the results of experimental tests focused on the dynamic response of wall panels of a wooden frame building with thermal isolation made of mineral wool and polyurethane foam. Firstly, the static and the dynamic mechanical analysis (DMA) tests were conducted so as to determine the basic thermomechanical properties of the analyzed isolation materials. Then, the elements of the exterior walls with two types of thermal insulation were tested under harmonic excitation for different amplitudes of displacement. The results of the static material tests indicate that the polyurethane foam behaves in a highly nonlinear way both during compression and tension. Moreover, the results of the DMA tests show that the storage and loss modulus of the polyurethane foam are significantly larger in relation to the values obtained for the mineral wool. The results of the dynamic tests on wall panels show that the use of polyurethane foam as thermal isolation leads to a substantial increase in stiffness and damping properties, as compared to the case when the mineral wood is used.
Experimental study on models of cylindrical steel tanks under mining tremors and moderate earthquakes
- Daniel Burkacki
- Robert Jankowski
2019 Earthquakes and Structures
The aim of the study is to show the results of complex shaking table experimental investigation focused on the response of two models of cylindrical steel tanks under mining tremors and moderate earthquakes, including the aspects of diagnosis of structural damage. Firstly, the impact and the sweep-sine tests have been carried out, so as to determine the dynamic properties of models filled with different levels of liquid. Then, the models have been subjected to seismic and paraseismic excitations. Finally, one fully filled structure has been tested after introducing two different types of damages, so as to verify the method of damage diagnosis. The results of the impact and the sweep-sine tests show that filling the models with liquid leads to substantial reduction in natural frequencies, due to gradually increasing overall mass. Moreover, the results of sweep-sine tests clearly indicate that the increase in the liquid level results in significant increase in the damping structural ratio, which is the effect of damping properties of liquid due to its sloshing. The results of seismic and paraseismic tests indicate that filling the tank with liquid leads initially to considerable reduction in values of acceleration (damping effect of liquid sloshing); however, beyond a certain level of water filling, this regularity is inverted and acceleration values increase (effect of increasing total mass of the structure). Moreover, comparison of the responses under mining tremors and moderate earthquakes indicate that the power amplification factor of the mining tremors may be larger than the seismic power amplification factor. Finally, the results of damage diagnosis of fully filled steel tank model indicate that the forms of the Fourier spectra, together with the frequency and power spectral density values, can be directly related to the specific type of structural damage. They show a decrease in the natural frequencies for the model with unscrewed support bolts (global type of damage), while cutting the welds (local type of damage) has resulted in significant increase in values of the power spectral density for higher vibration modes.