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Gdańsk University of Technology

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Publications from the year 2018

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  • 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 Full text 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 Full text 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 Full text 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.

  • The Impact of Building Performance Analysis on intuition Development and Decision Making Rationality
    • Maria Helenowska-Peschke
    2018

    Contemporary architectural workshop is characterized by the ability to efficiently collect and process huge amounts of geometric and non-geometric information. Virtual substitutes for buildings and structures allow to analyze various aspects of real life activity at various stages of the design process. The possibility of increased prognostic quantitative data acquisition, such as cost of energy consumption, shifts architectural practice towards rationalizing design decisions and multi-criteria objectivization. The article presents a view in the discussion on the importance of digital tools for building energy modelling and daylight simulation in the initial conceptual design phase for shaping architectural intuition and empowering design decisions. Issues related to the methodology of digital design, along with the possibilities and limitations of currently available tools tailored to the needs of architects will be discussed.

  • The impact of cooking method on the phenolic composition, total antioxidant activity and starch digestibility of rice (Oryza sativa L.)
    • Tomasz Chmiel
    • Irfan Estiono Saputro
    • Barbara Kusznierewicz
    • Agnieszka Bartoszek-Pączkowska
    2018 Full text JOURNAL OF FOOD PROCESSING AND PRESERVATION

    This study investigated changes in the phenolic composition, total antioxidant activity (TAA) and starch digestibility in white and brown rice due to three different cooking procedures, and subsequent reheating of cooked rice after storage. Among the analyzed samples, brown rice showed the highest TAA and phenolic content (622.5 mg kg-1 DW). All cooking methods resulted in significant decrease of phenolic content and TAA of rice (p<0.05). The greatest loss was observed after processing in rice cooker, which reduced phenolic content of both brown and polished rice by ∼30% and ABTS radical-scavenging activity by 20% and 28%, respectively. In general, the levels of polyphenols and TAA of cooked rice tended to further decline after storage and reheating, but to a much lesser extent when rice was prepared using microwaves. The application of in vitro digestion system disclosed that the microwave cooking resulted in the highest starch digestibility among cooking methods used. PRACTICAL APPLICATION: Rice is one of the most commonly consumed staple foods worldwide. Scientific and epidemiological studies have showed that their phytochemicals exhibit antioxidant, anti-inflammatory, antihypertensive and chemopreventive effects. Therefore, their high consumption, easy availability throughout the year and use as an additive to meat and high-fat foods may make rice, especially in the form of whole grains, potentially important chemopreventive component of the diet. The appriopriate cooking procedure of rice is crucial for preservation of bioactive compounds as well as digestion of starch and thus duration of the glycemic response. Preferably, this study is focused on the evaluation of the effect of cooking methods on the health-related quality of rice. The results provide practical advice that the consumption of freshly cooked rice ensures its highest nutritional quality, while rice microwaving is recommended both when cooked rice is reheated after storage (e.g. in restaurants) and accelerated starch digestion is in favour.

  • The Impact of Forms of Buildings on the Air Exchange in Their Environment. Based on the Example of Urban Development in Warsaw
    • Katarzyna Zielonko-Jung
    • Marta Poćwierz
    2018

    Possibilities for energy-efficient, natural ventilation of buildings in an urban environment depend on the airflow around them. This chapter deals with the issue of dependence of air exchange in urban spaces on the building forms used in them and on relative position of these buildings. The authors focused on the problem of air stagnation in dense urban development. This phenomenon increases the energy demand of buildings. The purpose of the following study is to present this problem and identify it in the selected example of existing settlements in Warsaw. The existing situation was compared with the revised spatial layout. The conclusions relate to spatial features of those building arrangements that are exposed to the problem of insufficient ventilation.

  • The Impact of Long-Time Chemical Bonds in Mineral-Cement-Emulsion Mixtures on Stiffness Modulus
    • Bohdan Dołżycki
    • Mariusz Jaczewski
    • Cezary Szydłowski
    2018 Full text Baltic Journal of Road and Bridge Engineering

    Deep cold in-place recycling is the most popular method of reuse of existing old and deteriorated asphalt layers of road pavements. In Poland, in most cases, the Mineral-Cement-Emulsion mixture technology is used, but there are also applications combining foamed bitumen and cement. Mineral-Cement-Emulsion mixtures contain two different binding agents – cement as well as asphalt from the asphalt emulsion. Asphalt creates asphalt bonding (responsible for flexible behaviour), whereas cement generates hydraulic bonds (responsible for stiffness of the layer). Final properties of Mineral- Cement-Emulsion mixtures are a result of a combination of both binding agents. While the stiffness of the material is unaffected by asphalt bonding, an increase in stiffness with time is visible for materials treated with hydraulic binders. This publication presents the change in stiffness modulus of Mineral-Cement-Emulsion mixtures by Simple Performance Test. For the analysis, two batches of specimens were used: the first was tested 28 days after compaction (period stated in Polish recommendations) and the second was tested 1.5 years after compaction. Analysis showed that after 1.5 years the stiffness modulus increased by about 10% in comparison to the 28 days after compaction. The change is minor but still significant. Unexpectedly, the level of the increase was unaffected by the combination of the binding agents (asphalt emulsion, cement).

  • The impact of the shape of deep drilled well screen openings on the filtration process in full saturation conditions
    • Barbara Wilk
    • Aleksander Urbański
    2018 Full text Czasopismo Techniczne

    The authors propose a supplementary method of modelling seepage flow around the deep drilled well screen. The study applies 3D numerical modelling (FEM) in order to provide an in-depth analysis of the seepage process. The analysis of filtration parameters (flow distribution q(x,t) and pressure distribution p) was conducted using the ZSoil.PC software system. The analysis indicates that the shape of perforation is of secondary importance during the deep bore well screen selection.

  • The Implementation of Fuzzy Logic in Forecasting Financial Ratios
    • Tomasz Korol
    2018 Full text Contemporary Economics

    This paper is devoted to the issue of forecasting financial ratios. The objective of the conducted research is to develop a predictive model with the use of an innovative methodology, i.e., fuzzy logic theory, and to evaluate its effectiveness. Fuzzy logic has been widely used in machinery, robotics and industrial engineering. This paper introduces the use of fuzzy logic for the financial analysis of enterprises. While many current phenomena in finance and economics are fuzzy, they are treated as if they are crisp. Fuzzy logic provides an appropriate tool for modeling imprecise, uncertain and ambiguous phenomena. Because the financial situation of a company is affected by many factors (economic, political, psychological, etc.) that cannot be precisely and unambiguously defined, the approach used in this paper greatly enhances the predictive power of financial analysis and makes it an economically useful tool for the management of enterprises. Empirically, this paper employs three testing samples: Central European enterprises, Latin American companies and global firms. From the verification of these models, it is evident that the refined processes are effective in improving the forecasting of financial situations of all three types of enterprises. The models created by the author are characterized by high efficiency. This study is one of the world’s first attempts to combine ratio analysis with fuzzy logic to predict the financial situations of companies

  • The influence of a change in the meniscus cross-sectional shape on the medio-lateral translation of the knee joint and meniscal extrusion
    • Piotr Luczkiewicz
    • Karol Daszkiewicz
    • Wojciech Witkowski
    • Jacek Chróścielewski
    • Tomasz Ferenc
    • Boguslaw Baczkowski
    2018 Full text PLOS ONE

    Objective The purpose of this study was to evaluate the influence of a change in the meniscus cross sectional shape on its position and on the biomechanics of a knee joint. Methods One main finite element model of a left knee joint was created on the basis of MRI images. The model consisted of bones, articular cartilages, menisci and ligaments. Eight variants of this model with an increased or decreased meniscus height were then prepared. Nonlinear static analyses with a fixed flexion/extension movement for a compressive load of 1000 N were performed. The additional analyses for those models with a constrained medio-lateral relative bone translation allowed for an evaluation of the influence of this translation on a meniscus external shift. Results It was observed that a decrease in the meniscus height caused a decrease in the contact area, together with a decrease in the contact force between the flattened meniscus and the cartilage. For the models with an increased meniscus height, a maximal value of force acting on the meniscus in a medio-lateral direction was obtained. The results have shown that the meniscus external shift was approximately proportional to the meniscus slope angle, but that relationship was modified by a medio-lateral relative bone translation. It was found that the translation of the femur relative to the tibia may be dependent on the geometry of the menisci. Conclusions The results have suggested that a change in the meniscus geometry in the cross sectional plane can considerably affect not only the meniscal external shift, but also the medio-lateral translation of the knee joint as well as the congruency of the knee joint.

  • The influence of anchoring group position in ruthenium dye molecule on performance of dye-sensitized solar cells
    • Maciej Zals
    • Błażej Gierczyk
    • Alberto Bossi
    • Patrizia Romana Mussini
    • Maciej Klein
    • Radosław Pankiewicz
    • Małgorzata Makowska-janusik
    • Łukasz Popenda
    • Waldemar Stampor
    2018 Full text DYES AND PIGMENTS

    The effect of anchoring group position and, in consequence, the orientation of the ruthenium dye molecule on titania surface on the performance of dye-sensitized solar cells has been studied intensively. Three model ruthenium sensitizing dyes bearing carboxylic anchoring group in ortho, meta or para position were synthesized and well characterized by spectroscopic, electrochemical, photophysical and photochemical measurements. The results were confronted with the quantum-mechanical calculations and discussed. The para derivative has been found as the most effective sensitizer with the cells efficiency twice higher than the meta and four times higher than the ortho derivatives.

  • The influence of different glycerine purities on chemical recycling process of polyurethane waste and resulting semi‐products
    • Patrycja Jutrzenka Trzebiatowska
    • Agata Dzierbicka
    • Natalia Kamińska
    • Janusz Datta
    2018 Full text POLYMER INTERNATIONAL

    Chemical recycling is the most favourable recycling method due to the possibility of polyol recovery. This work is dedicatedto the utilisation of crude glycerine and polyurethane waste. It aims at determining the impact of the use of glycerine fromthe production of biodiesel with various degrees of purity as a cleavage agent on the decomposition process of polyurethanefoam. The influence of glycerine purit y on the chemical structure of recycling products was analysed using Fourier transforminfrared and1H NMR spectroscopies and gel permeation chromatography. Hydroxyl and amine values were determined, andrheological measurements were performed. Glycerolysates showed minor structural differences due to the presence of aminegroups and exhibited heterogeneous structure compared to original polyols. The ones obtained in decomposition using 84and 99.5% glycerine had a lower viscosity below 0.45 Pa s at 50∘C and higher hydroxyl number of 183 and 220 mg KOH g−1,respectively, compared to the ones obtained with glycerine purity of 40 and 62% due to a different chemical struc ture. All ofthe products of decomposition were defined as non-Newtonian fluids, where viscosity depended on the shear rate. Selectedglycerolysates were used in the production of cast polyurethanes with satisfactory mechanical properties.

  • The influence of historical conditions on time and cost of construction project
    • Magdalena Apollo
    • Beata Grzyl
    • Jakubowicz Paweł
    2018 Full text

    Conducting construction works in a building or in an area entered in the historic register is associated with the contracting authority's risk of incurring higher than planned costs of works, as well as delays in their implementation. In many cases, these deviations are completely independent of contracting authority and contractor. The aim of this article is to indicate the reasons for cost and time changes in the construction project, which is influenced by the historical conditions of the building site's location. In practice, the detailed considerations presented in the article may contribute to increasing the efficiency of spending public funds in the implementation of construction projects of a specific nature. Based on the selected example - reconstruction of the Old Pharmacy building located in the historic part of the old city of Gdańsk, the authors analyze and classify factors affecting the cost and time of construction works taking into account the historical conditions of the location of the facility.

  • The Influence of LED Lighting Sources on the Nature of Power Factor
    • Mirosław Włas
    • Stanisław Galla
    2018 Full text ENERGIES

    This article presents measurements of electric power absorbed by a newly built facility for office and scientific research activities. These measurements highlighted the need for compensation of capacitive reactive power—not predicted by the designer—due to the vast use of LED lighting in the facility. The article also describes a reactive power compensation system, designed on the basis of the above-mentioned measurements, and the introduced control and measurement system that enables on-site monitoring and online analysis of consumed energy and power. The research was carried out using popular LED lighting sources available on the local market (Poland). Basic electrical parameters of the locally available LEDs were measured as a function of the changes in harmonic levels occurring in the supply voltage. The test illustrated that samples were characterized by a very low power factor, which decreased as the level of harmonic disturbances increased. On the basis of the measurements, the authors suggest that obligatory requirements should be introduced in regard to the minimum power factor at the level of 0.9 for popular LED lighting sources (below 25 W)

  • The influence of microjet array area ratio on heat transfer in the compact heat exchanger
    • Tomasz Muszyński
    2018 Full text EXPERIMENTAL THERMAL AND FLUID SCIENCE

    The paper describes the comprehensive study on the effect of microjet array geometrical parameters on the heat transfer enhancement in the modular heat exchanger. The conducted experimental study provides an experimental database on single phase submerged microjet heat transfer. The Wilson plot method was applied to determine the heat transfer coefficients in the laminar and transition flow regimes of a liquid-to-liquid heat exchanger. The heat exchanger was capable of exchanging 296 W of thermal energy at LMTD of 44 K. The obtained heat transfer coefficient reaches over 24,000 W/m2 K. Average Nusselt number predictions of the Wen and Jang (2003) correlation were in best agreement with the experimentally determined average Nusselt numbers. In the whole tested flow range, Nusselt numbers were not well correlated by any of the correlations from the literature. The experimentally determined Nusselt numbers were significantly lower than expected, due to limited applicability of given literature correlations. The author also proposed own experimental correlation for jet impingement heat transfer coefficient, predicting the experimental results within 30%.

  • THE INFLUENCE OF PHASE SHIFTERS ON THE VOLTAGE STABILITY OF CONNECTED POWER SYSTEMS
    • Ryszard Zajczyk
    • Piotr Szczeciński
    2018

    The paper presents the results of simulation tests of connected power systems in which phase shifters were installed on cross-border links. The analysis was carried out in terms of assessing the impact of shifters on node voltage stability. Individual systems were characterized by different balance of active power: deficit or excess. The evaluation of voltage stability was based on the dU/dQ and dU/dP criteria.