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Gdańsk University of Technology

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Publications from the year 2019

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  • Detekcja warunków LOS i NLOS w środowisku wewnątrz budynkowym przy użyciu algorytmu głębokiego uczenia
    • Alicja Olejniczak
    • Krzysztof Cwalina
    • Piotr Rajchowski
    • Jarosław Sadowski
    2019 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    W środowisku wewnątrzbudynkowym występuje wiele czynników negatywnie wpływających na transmitowane sygnały. Niniejszy artykuł przedstawia metodę opartą na koncepcji głębokich sieci neuronowych, służącą do detekcji warunków LOS i NLOS w środowisku wewnątrzbudynkowym. Algorytm opracowany i przetestowany został na podstawie pomiarów sygnałów UWB przeprowadzonych w rzeczywistym środowisku wewnątrzbudynkowym.

  • Determinants of Business Growth Aspirations among Polish Students: An Empirical Analysis
    • Krzysztof Zięba
    • Jakub Golik
    2019

    This paper aims to discuss the concept of growth aspirations and growth intentions, as well as to identify factors that influence growth aspirations expressed by students with regard to their future businesses. On the basis of a literature review potential determinants of growth aspirations have been identified and tested empirically using data obtained from 223 students from the Pomeranian region in Poland. The authors use Binomial Logistic Regression to propose an econometric model with endogenous variable Growth Aspiration. The results of the study show that from the set of chosen variables, surprisingly some turned out to be statistically insignificant i.a. entrepreneurial self-efficacy, entrepreneurial intention or risk propensity. Eventually, four of the variables have been found to influence declared growth aspirations of respondents in a statistically significant way, namely: gender, declared resistance to stress, perception of higher income being one of the most attractive feature of entrepreneurship and belief that prestige also belongs to the most attractive features of entrepreneurship. Research results are limited to students from one university only and as such, they cannot be perceived as representative for the whole country. Nevertheless, the findings of empirical analysis of growth aspirations determinants allow to identify factors that may decide whether entrepreneurial endeavours undertaken in the future will be intended to be high growth businesses. The paper contributes to a better understanding of the difference between growth aspirations and growth intentions. It also shows what factors shape business growth aspirations of students, which may impact the actual growth of their businesses in the future.

  • Determination and identification of organic acids in wine samples. Problems and challenges.
    • Alicia Robles
    • Magdalena Fabjanowicz
    • Tomasz Chmiel
    • Justyna Płotka-Wasylka
    2019 Full text TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    For long time, organic acids were underestimated. However, during last two decades there is an increasing interest of natural compounds having antioxidant, antimicrobial and anti-inflammatory properties thus organic acids are very preferable. Wine stands as one of the sources of organic acids since they are responsible for its organoleptic and aestethic character. Nevertheless, it is important to not exceed acceptable level of acidity at particular stage of vinification process. Therefore its determination and quantification is of high importance. Given study gathers data regarding current knowledge with respect to organic acids, focusing on their occurrence in different types of food including wines, their properties and effects on the human body, potential correlations between organic acids and other components of wine. Moreover, the comparison of analytical techniques used for the organic acids determination and challenges, considering their process and green assessment is provided.

  • Determination of Antioxidant Activity of Vitamin C by Voltammetric Methods
    • Klaudia Suliborska
    • Monika Baranowska
    • Agnieszka Bartoszek-Pączkowska
    • Wojciech Chrzanowski
    • Jacek Namieśnik
    2019 Full text Proceedings

    Voltammetric methods—cyclic (CV) and differential pulse voltammetry (DPV) are considered the most appropriate way to evaluate antioxidant activity of redox active compounds. They provide information about both mechanism and kinetics of electrochemical oxidation of antioxidants as well as their physical and chemical properties such as the redox potential or the number of electrons transferred. These methods are helpful for understanding the mechanisms of oxidation or reduction processes of antioxidant compounds. This work presents the electrochemical properties of vitamin C obtained by both CV and DPV methods.

  • Determination of buckling strength of silos composed of corrugated walls and thin-walled-columns using simplified wall segment models
    • Piotr Iwicki
    • Karol Rejowski
    • Andrzej Tejchman-Konarzewski
    2019 THIN-WALLED STRUCTURES

    W artykule przedstawiono wyniki obszernych analiz numerycznych wyboczenia i stateczności metalowych silosów z blachy falistej wzmocnionych cienkościennymi słupami. Wykonano analizy liniowe i nieliniowe. Do obliczeń zaproponowano proste modele segmentów ścian zamiast skomplikowanych modeli całych silosów. Otrzymano bardzo dobrą zgodność wyników numerycznych. Wyniki obliczeń numerycznych porównano dodatkowo z wynikami normowymi.

  • Determination of free tyrosine in equestrian supplements by LC–MS/MS and comparison of its quantity with total free amino acids content in view of doping control
    • Emilia Waraksa
    • Konrad Kowalski
    • Rafał Rola
    • Ewa Kłodzińska
    • Tomasz Bieńkowski
    • Jacek Namieśnik
    2019 MICROCHEMICAL JOURNAL

    The reports on the probable beneficial impact of tyrosine (TYR) supplementation on performance enhancement have contributed to the growth of interest in TYR in equestrian sports field and related industries, such as the manufacture of dietary and nutritional supplements. In this study, the first attempt to the assessment of horses exposure to TYR during nutritional supplementation was demonstrated by quantification of unbound TYR and a total free amino acids (AAs), and subsequent determination of the ratio of TYR to a total free AAs content in equestrian supplement samples. Within the scope of this study, a rapid and sensitive LC–MS/MS-based method for the determination of unbound TYR and a simple spectrophotometric protocol for the quantification of a total free AAs have been developed and validated according to the international guidelines for bioanalytical methods. For sample preparation, an ultrasound-assisted solid-liquid extraction (USLE; for solid samples) and ultrasound-assisted liquid-liquid extraction (ULLE; for liquid samples) have been optimized. The comprehensive approach on the simultaneous assessment of matrix effect, recovery, process efficiency, accuracy, precision, curve factor and internal standard association demonstrated satisfactory validation parameters for LC–MS/MS-based procedure, such as global matrix effect in the range of 89.9–91.9%, good linearity (R2 > 0.9929), limit of detection (0.6 ng/mL) and recovery within 89.2–108.0%. For spectrophotometric method, limit of detection was 1100 ng/mL, recovery ranged from 103.2 to 108.8%, both, intra- and inter-day accuracy was within 89.5–108.7%, and both, intra- and inter-assay precision was below 8.5%. In view of the satisfactory validation parameters obtained for both methods, the procedures can be utilized for routine analysis of dietary and nutritional supplements.

  • Determination of heavy metals in eyeshadows from China
    • Lesław Świerczek
    • Bartłomiej Cieślik
    • Adrianna Matysiak
    • Piotr Konieczka
    2019 Full text MONATSHEFTE FUR CHEMIE

    Personal care products and cosmetics are used daily by many people, causing local exposure to certain chemical substances through the application directly inside the oral cavity, on the skin, lips, eyes, and mucosa. Eyeshadows are among the most commonly used types of cosmetics. According to scientifc reports, they may contain heavy metals, especially in non-original products. The exposure to said heavy metals may cause local skin irritation, sensitization, and allergy. Due to the fact that they are applied around the eyes, where the skin is relatively thin, it is likely that heavy metals can get into the bloodstream which may pose a threat to consumers’ health. In the described research, the analysis of eyeshadows from two palettes of generic alternatives to the original eyeshadows was presented. The determination of Zn, Ni, Cd, Cu, and Pb was conducted using atomic absorption spectrometry. Based on the analysis of the obtained results, it was shown that the content of some heavy metals in generic eyeshadows exceeds the acceptable standards.

  • Determination of moisture resistance of covered electrodes according to PN-EN ISO 14372
    • Katarzyna Mielnicka
    • Adrian Wolski
    • Aleksandra Świerczyńska
    • Grzegorz Rogalski
    • Dariusz Fydrych
    2019 Full text Przegląd Spawalnictwa

    Moisture present in the electrode covering is one of the sources of diffusible hydrogen in welded joints. In order to study the diffusible hydrogen content in deposited metal, a stand for moisturizing covered electrodes, in accordance with the PN-EN ISO 14372 standard, was built. After the stand was completed, a test of moisturizing the electrodes was carried out and measurements of the diffusible hydrogen content in deposited metal using the mercury method (according to PN-EN ISO 3690) were conducted. The research was aimed at verifying the correctness of the operation of test stand and indirect determination of the influence of storage of rutile-cellulose and cellulose electrodes under fixed conditions on the degree of moisturizing of the weld metal. Both tested electrode grades belong to the group of electrodes with a standard covering.

  • Determination of Odor Intensity of Binary Gas Mixtures Using Perceptual Models and an Electronic Nose Combined with Fuzzy Logic
    • Bartosz Szulczyński
    • Jacek Gębicki
    2019 Full text SENSORS

    Measurement and monitoring of air quality in terms of odor nuisance is an important problem. From a practical point of view, it would be most valuable to directly link the odor intensity with the results of analytical air monitoring. Such a solution is offered by electronic noses, which thanks to the possibility of holistic analysis of the gas sample, allow estimation of the odor intensity of the gas mixture. The biggest problem is the occurrence of odor interactions between the mixture components. For this reason, methods that can take into account the interaction between components of the mixture are used to analyze data from the e-nose. In the presented study, the fuzzy logic algorithm was proposed for determination of odor intensity of binary mixtures of eight odorants: n-Hexane, cyclohexane, toluene, o-xylene, trimethylamine, triethylamine, α-pinene, and β-pinene. The proposed algorithm was compared with four theoretical perceptual models: Euclidean additivity, vectorial additivity, U model, and UPL model.

  • Determination of Peak Impact Force for Buildings Exposed to Structural Pounding during Earthquakes
    • Seyed Mohammad Khatami
    • Hosein Naderpour
    • Carneiro Rui Barros
    • Anna Jakubczyk-Gałczyńska
    • Robert Jankowski
    2019 Full text Geosciences

    Structural pounding between adjacent, insufficiently separated buildings, or bridge segments, has been repeatedly observed during seismic excitations. Such earthquake-induced collisions may cause severe structural damage or even lead to the collapse of colliding structures. The aim of the present paper was to show the results of the study focused on determination of peak impact forces during collisions between buildings exposed to different seismic excitations. A set of different ground motion records, with various peak ground acceleration (PGA) values and frequency contents, were considered. First, pounding-involved numerical analysis was conducted for the basic parameters of colliding buildings. Then, the parametric study was carried out for different structural natural periods, structural damping ratios, gap sizes between buildings and coefficients of restitution. The results of the analysis conducted for the basic structural parameters indicate that the largest response of the analysed buildings was observed for the Duzce earthquake. The parametric study showed that the pounding-involved structural response depended substantially on all parameters considered in the analysis, and the largest response was observed for different ground motions. The results of the study presented in this paper indicate that the value of the peak impact force expected during the time of the earthquake does not depend on the PGA value of ground motion, but rather on the frequency contents of excitation and pounding scenario. It is therefore recommended that the peak impact force for buildings exposed to structural pounding during earthquakes should be determined individually for the specific structural configuration taking into account the design ground motion.

  • Determination of polycyclic aromatic hydrocarbons (PAHs) and other organic pollutants in freshwaters on the western shore of Admiralty Bay (King George Island, Maritime Antarctica).
    • Małgorzata Szopińska
    • Danuta Szumińska
    • Robert Józef Bialik
    • Tomasz Dymerski
    • Erwin Rosenberg
    • Żaneta Polkowska
    2019 Full text ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

    Organic contamination in freshwater samples has never been investigated at the western shore of Admiralty Bay. Therefore, the presence of polycyclic aromatic hydrocarbons (PAHs) in five different sites distributed along a shore running from the Arctowski Station to the Baranowski Glacier was studied. Moreover, organic compounds such as n-alkanes, toluene and ethylbenzene were also noted. Increased ΣPAHs in late Austral summer 2016 are the result of long-range atmospheric transport of air masses from South America, confirmed by 10-day backward air mass trajectories analysis. The presence of n-alkanes and other hydrocarbons, as well as the evaluation of PAH indices (e.g. ΣLMW/ΣHMW* > 1), shows the use of fuel and indicate local human activity. As a final conclusion, our analysis indicates a mixed origin of PAHs (global and local). The presence of PAHs and other hydrocarbons in the water environment may constitute a potentially negative effect on the Antarctic ecosystem and it should be investigated in detail during further research (//*ΣLMW—sum of low molecular weight PAHs (two- and three-ring PAHs); ΣHMW—sum of high molecular weight PAHs (four- and five-ring PAHs)//).

  • Determination of selected parameters/ analytes in surface water samples collected in the surroundings of the capital of Spitsbergen (Longyearbyen)
    • Ruman Marek
    • Michał Ciepły
    • Żaneta Polkowska
    2019 Full text AIP Conference Proceedings

    Polar regions are extremely sensitive to pollution such as harmful gases, particles or toxic substances which affect the Arctic climate and ecosystems. Spitsbergen, as well as all Arctic region, because of its geographically distant location and lack of industry sector, should be free of chemical pollution. Despite this, many pollutants could be found in the Polar environment, for example in freshwaters. Their occurrence is related with the global distillation process (Grasshopper effect) in which the contaminants from lower latitudes are transferred to the higher latitudes, resulting in the pollution of Arctic area. The purpose of the research was to determine the selected parameters: TOC (Total Organic Carbon) and formaldehyde, phenols in samples of freshwaterwater (surface water) collected in the area surrounding the capital of Spitsbergen (Longyearbyen). The aim was to investigate the pollution of Arctic freshwater. The obtained results of detected compounds may confirm the role of transport of contaminants over large distances in pollution of Polar regions.

  • Determination of the uncertainty of mass flow measurement using the orifice for different values of the Reynolds number
    • Anna Golijanek-Jędrzejczyk
    • Andrzej Mrowiec
    • Robert Hanus
    • Marcin Zych
    • Dariusz Świsulski
    2019 Full text

    Standard orifice flowmeters are widely used in the chemical and energy industry. Therefore, it is essential to know how accurate the measurements made with these instruments are. The paper presents an estimation of measurement uncertainty of a liquid mass flow using the orifice plate. The authors will present the influence of ranges of the Reynolds number on the estimated uncertainty, obtained on the basis of simulation and laboratory experiments. The research was conducted for the central orifice in the Reynolds number 8,000 < Re < 21,000. The results of estimating the extended uncertainty of the measurement of water flow using simulation and experimental method, are convergent. The maximum difference in the extended uncertainty values of flow measurement for the simulation and experiment was 0.04.10-3 kg/s.

  • Determination of Thermophysical Parameters Involved in The Numerical Model to Predict the Temperature Field of Cast-In-Place Concrete Bridge Deck
    • Aleksandra Kuryłowicz-Cudowska
    2019 Full text Materials

    The paper dealswith a concept of a practical computationmethod to simulate the temperature distribution in an extradosed bridge deck. The main goal of the study is to develop a feasible model of hardening of concrete consistent with in-situ measurement capabilities. The presented investigations include laboratory tests of high performance concrete, measurements of temperature evolution in the bridge deck and above all, numerical simulations of temperature field in a concrete box bridge girder. A thermal conductivity equation in the author’s program, using finite dierence method has been solved. New approach for identification of the model parameters and boundary conditions (heat transfer coecients) has been proposed. The numerical results are verified by means of a wide set of experimental tests carried out on three stages of the extradosed bridge studies. A high agreement between the concrete temperature distribution in the time and space domain was obtained. The temperature history of concrete hardening, supplemented with maturity method equations, made it possible to estimate an early-age compressive strength of the cast-in-place concrete. The proposed solution could be applied in a Structural Health Monitoring system for concrete objects.

  • Developing a Framework for the Implementation of Landscape and Greenspace Indicators in Sustainable Urban Planning. Waterfront Landscape Management: Case Studies in Gdańsk, Poznań and Bristol
    • Joanna Badach
    • Elżbieta Raszeja
    2019 Full text Sustainability

    Urban landscape (UL) management and urban greenspace (UG) delivery require effective planning tools. The aim of the study is to develop a conceptual framework for the implementation of ecological, structural and visual landscape and greenspace indicators (LGI) in spatial development of urban areas. The UL and UG management provisions in Poland are identified at various levels of urban planning (local, municipal and regional). Furthermore, the applicability of the selected set of LGI in the Polish planning system is considered based on the existing planning documents. The quality of UL and UG transformation is discussed in three case studies in Bristol, Gda ´nsk and Pozna ´n in the broader context of the English and Polish spatial planning systems. Bristol is used as a point of reference for the evaluation of UL and UG management in Poland and for the comparison between English and Polish landscape policies. Based on the conceptual framework and the analysis of the case studies, critical areas of UL and UG management in Poland are identified. The existing planning system often fails to ensure the continuity of landscape structures, and it does not include its preservation and enhancement to a sufficient extent. Therefore, the implementation of the proposed LGI framework could significantly improve the ecological and visual quality, as well as the structural diversity of UL and UG. Moreover, the article concludes by indicating some practical implications of the proposed LGI framework for urban planners, policy makers and other stakeholders in terms of improving the modes of governance for UL and UG management as well as of accounting for human health and well-being.

  • Developing Novel Solutions to Realise the European Energy - Information Sharing & Analysis Centre
    • Rafał Leszczyna
    • Tania Wallis
    • Michał Wróbel
    2019 Full text DECISION SUPPORT SYSTEMS

    For more effective decision making in preparation for and response to cyberevents in the energy sector, multilevel situation awareness, from technical to strategic is essential. With an uncertain picture of evolving threats, sharing of the latest cybersecurity knowledge among all sector stakeholders can inform and improve decisions and responses. This paper describes two novel solutions proposed during the formation of the European Energy -- Information Sharing \& Analysis Centre (EE-ISAC) to build situation awareness and support information sharing. The development of the EE-ISAC towards regular information sharing among members is described. This demonstrates the foundations achieved so far upon which a situation awareness network can be built for the energy sector.

  • Development and validation of a model that includes two ultrasound parameters and the plasma D-dimer level for predicting malignancy in adnexal masses: an observational study
    • Maciej Stukan
    • Michał Badocha
    • Karol Ratajczak
    2019 Full text BMC CANCER

    Background: Pre-operative discrimination of malignant from benign adnexal masses is crucial for planning additional imaging, preparation, surgery and postoperative care. This study aimed to define key ultrasound and clinical variables and develop a predictive model for calculating preoperative ovarian tumor malignancy risk in a gynecologic oncology referral center. We compared our model to a subjective ultrasound assessment (SUA) method and previously described models. Methods: This prospective, single-center observational study included consecutive patients. We collected systematic ultrasound and clinical data, including cancer antigen 125, D-dimer (DD) levels and platelet count. Histological examinations served as the reference standard. We performed univariate and multivariate regressions, and Bayesian information criterion (BIC) to assess the optimal model. Data were split into 2 subsets: training, for model development (190 observations) and testing, for model validation (n = 100). Results: Among 290 patients, 52% had malignant disease, including epithelial ovarian cancer (72.8%), metastatic disease (14.5%), borderline tumors (6.6%), and non-epithelial malignancies (4.6%). Significant variables were included into a multivariate analysis. The optimal model, included three independent factors: solid areas, the color score, and the DD level. Malignant and benign lesions had mean DD values of 2.837 and 0.354 μg/ml, respectively. We transformed established formulae into a web-based calculator (http://gin-onc-calculators.com/gynonc.php) for calculating the adnexal mass malignancy risk. The areas under the curve (AUCs) for models compared in the testing set were: our model (0.977), Simple Rules risk calculation (0.976), Assessment of Different NEoplasias in the adneXa (ADNEX) (0.972), Logistic Regression 2 (LR2) (0.969), Risk of Malignancy Index (RMI) 4 (0.932), SUA (0.930), and RMI3 (0.912). Conclusions: Two simple ultrasound predictors and the DD level (also included in a mathematical model), when used by gynecologist oncologist, discriminated malignant from benign ovarian lesions as well or better than other more complex models and the SUA method. These parameters (and the model) may be clinically useful for planning adequate management in the cancer center. The model needs substantial validation.

  • Development of beltless respiration and heartbeat sensor based on flexible piezoelectric film
    • Łukasz Sienkiewicz
    • Roland Ryndzionek
    • Mieczysław Ronkowski
    2019 Full text

    The main goal of this work is to report initial development on a respiration and heartbeat measurement sensor that can be used in continuous monitoring conditions at a minimal impact on the patient. General description of the sensor, consisting of a PVDF film and the bonding layer, is given. Open-circuit voltage generated by the sensor is estimated by analytical and numerical calculations. Analog and digital interface used to extract the bio-data is briefly described. Finally, signal conditioning with digital filters, as well as, measurements of respiration and heart rate at two locations are presented and discussed.

  • Development of Intelligent Road Signs with V2X Interface for Adaptive Traffic Controlling
    • Andrzej Czyżewski
    • Andrzej Sroczyński
    • Tomasz Śmiałkowski
    • Piotr Hoffmann
    2019 Full text

    The objective of this paper is to present a practical project of intelligent road signs, under which a series of new products for the regulation of traffic is being created. The engineering part of the project, described in this paper, was preceded by a series of experimental studies, the results of which were described in another paper accepted for publication at the MTS-ITS conference 2019, entitled "Comparative study on the effectiveness of various types road traffic detectors". A new kind of intelligent road signs which will enable the prevention of the most common collisions on highways, resulting from the rapid stacking of vehicles resulting most often from accidental heavy braking. A range of products is being developed, including intelligent road signs: standing, hanging and mobile ones, displaying dynamically updated driving the speed limit, determined automatically, through an embedded electronic module, enabling multimodal measurement of traffic conditions. Solving a number of research and construction problems, such as: effective and independent of weather conditions traffic monitoring based on simultaneous analysis of several types of data representation, development of a method of calculating gradients and histograms of vehicle speed for various types of road situations or traffic topologies. Moreover, creating a platform for self-organizing reliable wireless connections among road signs equipped with innovative displays and power supplies and carrying out prototype tests are carried out. As a result, advanced conceptually products for increasing road safety for which there is a market demand are being prepared for future implementation.

  • Diagnosing wind turbine condition employing a neural network to the analysis of vibroacoustic signals
    • Andrzej Czyżewski
    2019 Full text Journal of the Acoustical Society of America

    It is important from the economic point of view to detect damage early in the wind turbines before failures occur. For this purpose, a monitoring device was built that analyzes both acoustic signals acquired from the built-in non-contact acoustic intensity probe, as well as from the accelerometers, mounted on the internal devices in the nacelle. The signals collected in this way are used for long-term training of the autoencoder neural network. The appropriately trained network automatically detects deviations, signaling them to technical service. The applied methods of analysis of vibroacoustic signals and neural network training are the subject of the presented paper. In addition, the motion magnification of video is used for extracting information on vibrations of the whole wind turbine construction. Finally, spectral analysis is applied for detecting unnatural components presence meaning defects in both: visual and vibroacoustic representations. The process of reduction and construction of a wind turbine model is discussed with a particular emphasis on application to perform extensive tests of the developed methods and algorithms. [The research was subsidized by the Polish National Centre for Research and Development within the project “STEO—System for Technical and Economic Optimization of Distributed Renewable Energy Sources”, No. POIR.01.02.00-00-0357/16.]