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Gdańsk University of Technology

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Publications from the year 2018

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  • The Antimicrobial Potential of Bacteria Isolated from Honey Samples Produced in the Apiaries Located in Pomeranian Voivodeship in Northern Poland
    • Magdalena Pajor
    • Randy Worobo
    • Sławomir Milewski
    • Piotr Szweda
    2018 Full text International Journal of Environmental Research and Public Health

    The principal objective of this study was to determine whether the honeys produced in apiaries located in Pomeranian Voivodeship (Northern Poland) contain bacteria producing metabolites with growth inhibition potential against important human and animal pathogens. The pathogens included Staphylococcus aurues, Staphyloccocus epidermidis, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Candida albicans. From 12 samples of honey, 163 strains of bacteria were isolated. Activity against reference staphylococci: S. aurues ATCC 25923; S. aureus ATCC 29213; S. epidermidis 12228 was observed in 33 (20.3%), 38 (23.3%), and 41 (25.1%) isolates, respectively. High inhibitory activity was also found against Listeria monocytogenes ATCC 7644 in 34 strains (20.9%). Activity against Candida albicans ATCC 10231 and especially Gram-negative bacteria: Pseudomonas aeruginosa ATCC 27857 and Escherichia coli ATCC 25922 was rarely observed. Production of metabolites exhibiting activity against the three pathogens mentioned above was confirmed for 13 (7.8%), 3 (1.8%), and 2 (1.2%) isolates, respectively. Forty-six isolates were selected for further analysis. Within this group, metabolites synthesized by 18 producing strains (39.13%) inhibited growth of only one of the reference strains of pathogenic microorganisms. However, 14 (30.44%), 8 (17.39%), and 6 (13.04%) strains produced agents active against three, two, and four pathogens, respectively. Sequencing of the 16S rRNA gene revealed that 80.4% of these 46 producing strains belong to the genus Bacillus. However, some producing strains belonging to the genus of Peanibacillus, Lysinibacillus, Microbacterium, and Staphylococcus were also identified. Furthermore, the analysis of the sequences of 16S rRNA, as well as RAPD-PCR, exhibited a significant diversity in the strains tested, even in the case of bacteria isolated from the same honey (and classified to the same genus, usually Bacillus spp.). This observation suggests environmental origin (nectar, water, or pollen) of the producing strains. The research carried out confirmed that honey produced in Northern Poland is a promising source of strains of bacteria producing metabolites with antimicrobial activity.

  • The applicability of low-cost PM10 sensors for atmospheric air quality monitoring
    • Bartosz Szulczyński
    • Jacek Gębicki
    2018 Full text

    Described in this work are the results of field tests carried out in the Tricity Agglomeration between 01 April 2018 and 30 June 2018 in order to evaluate the usefulness of low-cost PM10 sensors in atmospheric air quality monitoring. The results were juxtaposed with the results obtained using reference methods. The results were validated based on the measurement uncertainty as described in the EU report "Demonstration of Equivalence of Ambient Air Monitoring Methods. EC Work ing Group on Guidance for the Demonstration of Equivalence". Moreover, the impact of external factors (humidity, pressure, temperature) on the obtained results was also assessed. It was shown that the low-cost sensors display measurement uncertainty which exceeds the acceptable values as compared to the reference methods and correction factors depending on the measured PM10 concentration need to be introduced in order to fulfil the criteria of equivalence.

  • The application of environmental issues in designing urban structures – a framework for comprehensive local planning policies
    • Joanna Badach
    2018 World Scientific News

    The implementation of environmental issues in planning and designing urban structures is becoming a novel approach and a common practice consistent with the paradigm of sustainable development. Maintaining environmental quality in urban areas, managing natural resources and understanding the complexity of urban systems is becoming increasingly challenging. Therefore, it is important to develop strategies for the integration of environmental quality research into urban planning policies and for the development of alternative spatial solutions for the existing urban structure which are aimed at improving environmental quality in urban areas. The aim of the article is to review contemporary theoretical and practical approaches towards the implementation of environmental issues within the process of urban planning in order to present a framework for local planning policies. Described is the research into spatial and design solutions which can efficiently reduce noise levels, mitigate atmospheric pollution and odour nuisance or prevent the negative effects of local microclimate effect. The possibility of application of design guidelines aimed at achieving environmental objectives in local planning documents is also assessed.

  • The application of microscopic models in the study of pedestrian traffic
    • Lucyna Gumińska
    • Jacek Oskarbski
    2018 Full text MATEC Web of Conferences

    Cities (especially in Central and Eastern Europe) focus on improving the road network, which aims to improve the efficiency of motor traffic and minimize congestion. Most of existing tools for analysing the effectiveness of urban transport networks do not assume to analyse the impact of walking and cycling on efficiency of transport systems. It is therefore necessary to develop solutions that on the one hand will reduce congestion, and on the other hand, improve the safety and quality of travel of vulnerable road users. One of the tasks to be developed in order to improve pedestrian conditions is to determine the relationship between pedestrian and vehicle traffic. An attempt has been made to establish the relationship between pedestrians and vehicle trafficin order to describe traffic conditions and pedestrian safety at pedestrian crossings. The analyseswere based on simulations carried out using the PTV Vissm/Viswalk software and with the use of surrogate safety measures.

  • The application of non-destructive methods in the diagnostics of the approach pavement at the bridges
    • Mikołaj Miśkiewicz
    • Jacek Lachowicz
    • Paweł Tysiąc
    • Piotr Jaskuła
    • Krzysztof Wilde
    2018 Full text IOP Conference Series: Materials Science and Engineering

    The article presents the possibility of using non-destructive methods of road pavement diagnostics as an alternative to traditional means to assess the reasons for premature cracks adjacent to bridge objects. Two scanning methods were used: laser scanning to measure geometric surface deformation and ground penetrating radar (GPR) inspection to assess the road pavement condition. With the use of a laser scanner, an effective tool for road deformation assessment several approach pavement surfaces next to the bridges were scanned. As the result, a point cloud was obtained including spatial information about the pavement deformation. The data accuracy was about 3 mm, the deformations were presented in the form of deviation maps between the reference surface and the actual surface. Moreover characteristic pavement surface cross-sections were presented. The in situ measurements of the GPR method were performed and analysed in order to detect non-homogeneity in the density of structural layers of the pavement. Due to the analysis of the permittivity of individual layers, it was possible to detect non-homogeneity areas. The performed GPR measurements were verified by standard invasive tests carried out by drilling boreholes and taking cores from the pavement and testing the compaction and air voids content in asphalt layers.. As a result of the measurements made by both methods significant differences in layer compacting factor values were diagnosed. The factor was much smaller in the area directly next to the bridgehead and much larger in the zone located a few meters away. The research showed the occurrence of both design and erection errors as well as those related to the maintenance of engineering structures.

  • The Application of Vibration Recording and Analysis in Tribological Research on Sliding Friction
    • Jacek Łubiński
    • Krzysztof Druet
    2018

    The paper reports on a tribological research on the macroscopic manifestation and characteristics of sliding friction. The aim of the task was to measure friction in lubricated sliding contacts and test the interactions between the environment (the test rig) and the experimental friction contact. Friction-induced vibrations were observed and studied as a manifestation of the process. The typical set of velocity and force/torque transducers was supplemented with a multi-channel vibration detection system. The vibro-diagnostic augmentation of the tribological experiment gave a new insight into the nature of motion of the system and load–velocity–friction relations. Modes of operation of the system were identified by spectral analysis in confrontation with natural frequencies of vibration of the test rig’s sub-systems.

  • The buckling analysis of a cold-formed steel C-sectional column resting on an elastic foundation
    • Patryk Deniziak
    • Piotr Iwicki
    2018 Full text MATEC Web of Conferences

    The paper is focused on stability analysis of different models of steel cold-formed C-section column. The analysed element may be applied as a primary load-bearing member in steel trusses or silo columns. The column can be used as a support for a wall of roof plates made of corrugated sheets. The wall sheeting that restrains the column against buckling may be considered as an elastic foundation. Due to the design solutions the foundation may be modelled as a series of lateral translational or rotational elastic supports. Such model is used for example in silo column analysis. In the paper linear bifurcation analysis (LBA) of axially compressed columns with different type of elastic foundation is carried by means of ABAQUS software. The analysed thin-walled column (C 250×100×33×4) is regarded as a load-bearing element in a steel hall. The column was modelled by shell elements, the foundation modelled by means of elastic supports. The column length was 5000 mm. The authors present a 3D image of an influence of lateral translational and rotational elastic supports on the buckling resistance of the column.

  • The Caustic in the Acoustics of Historic Interiors
    • Andrzej Kulowski
    2018 Full text APPLIED ACOUSTICS

    In the paper, caustics are discussed as ordered forms of focus broadening occurring in concave mirrors. Presented are examples of caustics formed in natural conditions and application of the phenomenon in different fields of science and technology. Against this factual background, the possibility to observe caustics in rooms is pointed out. Special emphasis is put on large rooms of historic character, as such interiors frequently include acoustic mirrors in the form of arched vaults and concave walls. As a case study, the eighteenth-century Whispering Grottoes representing one of attractions of the Oliwa Park in Gdańsk was selected, where the phenomenon of forming a caustic was used intentionally to obtain the desired acoustic effect.

  • The changes of crosslink density of polyurethanes synthesised with using recycled component. Chemical structure and mechanical properties investigations.
    • Patrycja Jutrzenka Trzebiatowska
    • Arantzazu Santamaria-Echart
    • Tamara Calvo-Correas
    • Arantxa Eceiza
    • Janusz Datta
    2018 Full text PROGRESS IN ORGANIC COATINGS

    This paper aims at the utilisation of glycerolysate (Gly) obtained in polyurethane recycling process by means of crude glycerine, which has in its structure hydroxyl end groups that allow for further processing. Polyurethanes (PUs) were synthesised using prepolymer method with the mixture of neat polyol and glycerolysate, in different ratios, with 4,4-diphenylmethane diisocyanate (MDI). The prepolymer was subsequently extended using 1,4-butanediol (BD). The incorporation of glycerolysate caused the crosslinking of obtained polyurethane materials. The crosslink density was calculated from swelling measurements by means of Flory and Rehner equation. The effect of recycled component content on the structure, thermal and mechanical properties were investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and mechanical tests, respectively. Morphology was also analysed by atomic force microscopy (AFM). As the content of recycled component increased, the swelling ratio decreased and simultaneously crosslink density increased, resulting in the increase of glass transition and storage modulus at room temperature. Thermomechanical stability, tensile strength, elastic modulus and hardness of PUs also increased with the incorporation of glycerolysate. Although elongation at break decreased, the recoverable deformation increased with the content of glycerolysate. Morphology reveals the transition from a microphase-separated microstructure to an interconnected hard segments domain structure with the incorporation of glycerolysate. These materials can be applied as protective coatings.

  • The circle object detection with the use of Msplit estimation
    • Artur Janowski
    2018

    The paper presents the use of Msplit(q) - estimation in the filtration and aggregation of point clouds containing a known number of elliptical shapes with preliminary unknown - locations and dimensions. These theoretical solutions may have practical relevance especially in the modelling of terrestrial laser scanning data of objects that have similar shape to circles. Mentioned shapes can be scanned of tree trunks, columns, gutters, etc., that are elliptical in the horizontal plane. The results are satisfied and encourage furthermore detailed research, particularly with the extension of 3D applications.

  • The Comparison of the Crypto- and Fiat Currencies’ Exchange Rate Volatility in The Years 2015–2017
    • Robert Sterniński
    2018 Full text Przedsiębiorczość i Zarządzanie

    The article describes the issues related to exchange rate volatility of crypto- and fiat currencies. The first part presents the issue of exchange rate volatility as well as methods of its evaluation and criteria of the conducted research. In the next part the author presented the essence of currencies and the main currency i.e. fiat money in the global economy in terms of the volume of transactions on the FOREX market. Then the main idea of crypto currency was presented – together with its advantages as well as disadvantages and main currencies in the economic cycle in terms of their market capitalization. Next, the results of research on exchange rate volatility in the time horizons were presented: 1-day, 1-week, 1-month and 1-year. The exchange rate fluctuations of EUR, JPY, GBP and BTC, ETH, XRP cryptocurrencies against the US dollar were analyzed. The article was concluded with a summary, which shows that cryptocurrencies are characterized by significantly greater exchange rate volatility against the so-called traditional currencies.

  • The concept of anti-collision system of autonomous surface vehicle
    • Andrzej Stateczny
    • Waldemar Gierski
    2018

    The use of unmanned vehicles in various fields of science and the economy is becoming more common. An extremely important aspect of creating this type of solution is to provide autonomous vehicle navigation, which does not require interference of the human factor or in which it is limited to a minimum. This article discusses the concept of autonomous anti-collision system of unmanned surface vehicle. It proposed a sensor system for the comprehensive implementation of the vehicle path in an automatic manner and presented the idea of remote sensing data fusion.

  • The concept of estimation of elevator shaft control measurement results in the local 3D coordinate system.
    • Daria Filipiak-Kowszyk
    • Waldemar Gierski
    • Waldemar Kamiński
    • Karolina Makowska
    2018

    Geodetic control measurements play an important part because they provide information about the current state of repair of the construction, which has a direct impact on the safety assessment of its exploitation. Authors in this paper have focused on control measurements of the elevator shaft. The article discusses the problem of determining the deviation of elevator shaft walls from the vertical plane in the local 3D coordinate system. It presents a concept of estimation of measurements results base on the parametric method with conditions on parameters. The simulated measurement results were used to verify the concept presented in the paper.

  • THE CONCEPT OF MODELING OF SNOW IMPACT ON THE STRUCTURE OF THE SUSPENDED TAURON ARENA ROOF IN CRACOW
    • Karol Grębowski
    2018

    The article presents studies and numerical simulations on modeling snow influence on TAURON ARENA suspended roof structure in Cracow. The scope of work includes experimental tests, functions solutions taking into account various cases of snow impact according to PN and EC, as well as numerical simulations for the sport and entertainment arena in the Czyzyny district. The FEM roof structure model developed in the SOFISITK software consists of bar and surface elements. The structure is made of bar elements, whereas the facade and the roof slope are made of surface elements. Finite element method meshing is developed using the Coons' method and four-node elements with six degrees of freedom are applied on each node. The conducted research and numerical analyses allowed for establishing a proper way of snow distribution on the load bearing elements of the structure. The results of the work will act as a guidelines for services dealing with the roof maintenance, and will minimize the risk of a collapse caused by improper snow removal.

  • The condition of economies. Do most valuable global brands matter?
    • Karol Flisikowski
    • Wioleta Kucharska
    2018 Full text EQUILIBRIUM Quarterly Journal of Economics and Economic Policy

    Research background: Brands are considered to be the most valuable asset of a company. Some of them achieve spectacular global results. The significance of global brands is proved by the fact that their value is often greater than the sum of all company’s net assets. Purpose of the article: The aim of this article is to highlight that brand value does not only create company’s value, but also leverages economies. The Authors claim that even though global brands are sold worldwide and are a part of “global factories”, they strongly relate to the development of economies in the countries where these brands’ headquarters are located. Methods: Based on 500 Brandirectory, the Most Valuable Global Brands ranking powered by Brand Finance, an analysis of spatial autocorrelation of brand values, GDP per capita was performed and also the interdependency between them was illustrated with the use of the spatial cross-regressive model (SCM). The SCM approach allowed us to include spatial effects of brand values into the final form of the estimated equation. The empirical analysis was performed for 33 countries in 2014. Findings & Value added: Findings confirm the hypothesis that there is a highly statistically significant relationship between brand value and GDP per capita and, what’s more, it is observed that spatial dependencies matter for brand values. The evidence is based on the results of spatial cross-regressive model (SCM).

  • The conducted EMI in DC-DC converters
    • Piotr Musznicki
    2018

    This book presents the phenomena of conducted electromagnetic interference (EMI) generation in DC-DC converters. The measurement and simulation are used to analyze the impact of the most important parameters on the character, level and propagation path of interference. In this book, the analysis of the interference generation and propagation is presented on the example of three basic converters. The wide banded behavior of all components is presented including basic elements and its parasitic and the connection layout. It focuses on the influence of parasitic components on the nature of interference in the frequency domain up to 30MHz was carried out. The book includes practical design and operation tips that will help to reduce the EMI. It provides useful knowledge about designing of the converters with the low level of outgoing EMI.

  • The consequences of applying a new Polish Water Law Act for protection against urban flooding
    • Ziemowit Suligowski
    • Nicole Nawrot
    2018 Full text E3S Web of Conferences

    Previous legal regulations did not create conditions for a comprehensive solution to the problems of the urban melioration complex. For over 20 years, urban flooding caused by atmospheric precipitation has been systematically recurring in Poland. The article was elaborated on the experience resulting from the 2001 and 2016 floods in Gdansk (Poland). The newly adopted Water Law Act creates a foundation for a systemic solution to previously neglected issues. A new supervisory authority has been introduced as ‘Polish Water’ (in the Polish nomenclature: Państwowe Gospodarstwo Wodne “Wody Polskie”). The Act takes into account the problems of flood risk management and counteracting the effects of drought.

  • The content of conjugated linoleic acid and vaccenic acid in the breast milk of women from Gdansk and the surrounding district, as well as in, infant formulas and follow-up formulas. Nutritional recommendation for nursing women
    • Dorota Martysiak-Żurowska
    • Bogumiła Kiełbratowska
    • Agnieszka Szlagatys-Sidorkiewicz
    2018 Full text Medycyna Wieku Rozwojowego

    Fatty acids are some of the most important components of human milk. Polyunsaturated fatty acids (PUFAs) are essential nutrients required for the optimal growth and development of infants, especially the central nervous system, brain and retina. AIM: To determine the conjugated linolenic acid (CLA) and vaccenic acid (VA) content of human breast milk from mothers consuming different diets, and to compare the results with CLA and VA levels in infant formulas (IF) and follow-up formulas (FF). MATERIAL AND METHODS: Fifty healthy mothers were classified according to their diet status into one of two groups: diet low in dairy products and conventional diet without limiting the intake of dairy products. Dietary intake of dairy fat was determined based on 3-day food diaries. Fatty acid (FA) composition in samples were analyzed by High Resolution Gas Chromatography (HR-GC). RESULTS: In the group of 20 mothers whose diets were deficient in dairy products, the average CLA content of breast milk fat was determined to be 0.27% of total FA, the VA 0.36%. In the group of 30 women consuming dairy products, the average content of CLA and VA in breast milk fat was statistically significantly higher: 0.49% and 0.69% of total FAs, respectively. In the fat of the IF and FF tested (n=11) only trace amounts of both FA were found. CONCLUSION: The results of the study indicate that CLA and VA concentrations of human milk can be influenced by diet. It is recommended that the source of these FAs in the diet of breastfeeding women are natural products and not dietary supplements. The majority of commercially available IF and FF do not contain sufficient amounts of CLA and VA, and that their FA composition is deficient in comparison with breast milk fat.

  • The criteria for evaluation and selection the best tender applied by the authorities in Poland and selected EU countries
    • Beata Grzyl
    • Magdalena Apollo
    • Emilia Miszewska-Urbańska
    • Adam Kristowski
    2018 Full text MATEC Web of Conferences

    The aim of the regulation in EU countries concerning public procurement is to ensure efficient spending of funds by evaluating and choosing the most advantageous offer. The aim of the conducted research is to determine the extent the Polish contracting entities benefit from the possibility of broad selection of various criteria for tender evaluation. On the basis of the analysis of 500 notices on work procedures conducted in the third quarter of 2016 - the third quarter of 2017 in open and restricted tenders in Poland and 500 tenders in open and restricted proceedings in five selected EU countries, the authors compared and classified of applied the practical criteria to evaluate and select the best offer. In order to collect the information presented in the article, the authors applied the documentary method using domestic and foreign literature regarding the subject and official publications.

  • The Diffusion of Information and Communication Technologies
    • Ewa Lechman
    2018

    This book provides extensive evidence on information and communication technologies development patterns and dynamics of this process across developed economies over the period 1980 to the present day. It adopts newly developed methodology to identification of the ‘critical mass’ and isolation of technological takeoff intervals, which are intimately related to the process of technology diffusion. The statistically robust analysis of country-specific data demonstrates the key economic, social and institutional prerequisites of ICT diffusion across examined countries, indicating what factors significantly foster or – reversely – hinder the process.