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Gdańsk University of Technology

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  • Combined thrust radial bearing of a submarine main shaft – Design and analysis of failure
    • Michał Wasilczuk
    • Filip Wasilczuk
    2020 Full text ENGINEERING FAILURE ANALYSIS

    This paper presents an analysis of the combined thrust radial bearing of a submarine propulsion shaft. The lubrication system of the bearing is based on a fixed ring. The efficiency of the lubrication system depends on the shaft speed and temperature, which affects oil viscosity. In turn, the thrust bearing load also depends on the rotational speed of the shaft, because as the speed increases, the drag of the ship increases simultaneously, but this increase in load is accompanied by the increase of load capacity of the hydrodynamic thrust bearing. The analysis made it possible to assess the causes of bearing failure and formulate recommendations for bearing operation.

  • Comments on various extensions of the Riemann–Liouville fractional derivatives : About the Leibniz and chain rule properties
    • Anna Szafrańska
    • Jacky Cresson
    2020 Communications in Nonlinear Science and Numerical Simulation

    Starting from the Riemann–Liouville derivative, many authors have built their own notion of fractional derivative in order to avoid some classical difficulties like a non zero derivative for a constant function or a rather complicated analogue of the Leibniz relation. Discussing in full generality the existence of such operator over continuous functions, we derive some obstruction Lemma which can be used to prove the triviality of some operators as long as the linearity and the Leibniz property are preserved. As an application, we discuss some properties of the Jumarie’s fractional derivative as well as the local fractional derivative. We also discuss the chain rule property in the same perspective.

  • Communication Model Order Reduction in Hybrid Methods Involving Generalized Impedance Matrix
    • Grzegorz Fotyga
    • Damian Szypulski
    • Rafał Lech
    • Piotr Kowalczyk
    2020 Full text IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    A novel strategy for the efficient analysis of frequency-domain scattering electromagnetic problems in open and closed domains is presented. A fully automatic model-order reduction technique, called the enhanced reduced-basis method, is applied to increase the efficiency of the hybrid approach, which combines the finite-element and mode-matching methods. Numerical tests show that the proposed algorithm yields reliable and highly accurate results whereas the computational time is reduced by up to one order of the magnitude.

  • Compact Dual-Polarized Corrugated Horn Antenna for Satellite Communications
    • Manshari Saeed
    • Sławomir Kozieł
    • Leifur Leifsson
    2020 Full text IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    In this paper, a structure and design procedure of a novel compact dual-polarized corrugated horn antenna with high gain and a stable phase center for satellite communication is presented. The antenna incorporates an Ortho-Mode Transducer (OMT), a mode converter, and a corrugated structure. The compact OMT section is designed to be fed by standard WR-75 waveguides. The proposed compact design utilizes only ten corrugated slots to yield a symmetric radiation pattern. The antenna impedance bandwidth (VSWR < 1.5) is 10.2 GHz to 15 GHz. Furthermore, the antenna exhibits 14 dBi to 17 dBi gain, a constant 30-degree HPBW radiation pattern, and less than 9mm phase center variation over the operating frequency range. The aperture diameter is 7 cm and the total antenna length is 15 cm. Due to the aforementioned features, the proposed antenna is suitable as the feed reflector for both uplink and downlink satellite communication. The design is validated numerically and experimentally.

  • Comparability of Raman Spectroscopic Configurations: A Large Scale Cross-Laboratory Study
    • Shuxia Guo
    • Claudia Beleites
    • Ute Neugebauer
    • Sara Abalde-Cela
    • Nils Kristian Afseth
    • Fatima Alsamad
    • Suresh Anand
    • Cuauhtemoc Araujo-Andrade
    • Sonja Aškrabić
    • Ertug Avci
    • Monica Baia
    • Malgorzata Baranska
    • Enrico Baria
    • Luis A. E. Batista de Carvalho
    • Philippe de Bettignies
    • Alois Bonifacio
    • Franck Bonnier
    • Eva Maria Brauchle
    • Hugh J. Byrne
    • Igor Chourpa
    • Riccardo Cicchi
    • Frederic Cuisinier
    • Mustafa Culha
    • Marcel Dahms
    • Catalina David
    • Ludovic Duponchel
    • Shiyamala Duraipandian
    • Samir F. El-Mashtoly
    • David I. Ellis
    • Gauthier Eppe
    • Guillaume Falgayrac
    • Ozren Gamulin
    • Benjamin Gardner
    • Peter Gardner
    • Klaus Gerwert
    • Evangelos J. Giamarellos-Bourboulis
    • Sveinbjorn Gizurarson
    • Marcin Gnyba
    • Royston Goodacre
    • Patrick Grysan
    • Orlando Guntinas-Lichius
    • Helga Helgadottir
    • Vlasta Mohaček Grošev
    • Catherine Kendall
    • Roman Kiselev
    • Micha Kölbach
    • Christoph Krafft
    • Sivashankar Krishnamoorthy
    • Patrick Kubryck
    • Bernhard Lendl
    • Pablo Loza-Alvarez
    • Fiona M. Lyng
    • Susanne Machill
    • Cedric Malherbe
    • Monica Marro
    • Maria Paula M. Marques
    • Ewelina Matuszyk
    • Carlo Francesco Morasso
    • Myriam Moreau
    • Howbeer Muhamadali
    • Valentina Mussi
    • Ioan Notingher
    • Marta Z. Pacia
    • Francesco S. Pavone
    • Guillaume Penel
    • Dennis Petersen
    • Olivier Piot
    • Julietta V. Rau
    • Marc Richter
    • Maria Rybarczyk
    • Hamideh Salehi
    • Katja Schenke-Layland
    • Sebastian Schlücker
    • Markus Schosserer
    • Karin Schütze
    • Valter Sergo
    • Faris Sinjab
    • Janusz Smulko
    • Ganesh D. Sockalingum
    • Clara Stiebing
    • Nick Stone
    • Valérie Untereiner
    • Renzo Vanna
    • Karin Wieland
    • Jürgen Popp
    • Thomas Bocklitz
    2020 Full text ANALYTICAL CHEMISTRY

    The variable configuration of Raman spectroscopic platforms is one of the major obstacles in establishing Raman spectroscopy as a valuable physicochemical method within real-world scenarios such as clinical diagnostics. For such real world applications like diagnostic classification, the models should ideally be usable to predict data from different setups. Whether it is done by training a rugged model with data from many setups or by a primary-replica strategy where models are developed on a ‘primary’ setup and the test data are generated on ‘replicate’ setups, this is only possible if the Raman spectra from different setups are consistent, reproducible, and comparable. However, Raman spectra can be highly sensitive to the measurement conditions, and they change from setup to setup even if the same samples are measured. Although increasingly recognized as an issue, the dependence of the Raman spectra on the instrumental configuration is far from being fully understood and great effort is needed to address the resulting spectral variations and to correct for them. To make the severity of the situation clear, we present a round robin experiment investigating the comparability of 35 Raman spectroscopic devices with different configurations in 15 institutes within seven European countries from the COST (European Cooperation in Science and Technology) action Raman4clinics. The experiment was developed in a fashion that allows various instrumental configurations ranging from highly confocal setups to fibre-optic based systems with different excitation wavelengths. We illustrate the spectral variations caused by the instrumental configurations from the perspectives of peak shifts, intensity variations, peak widths, and noise levels. We conclude this contribution with recommendations that may help to improve the inter-laboratory studies.

  • Comparative Analysis of Carbon, Ecological, and Water Footprints of Polypropylene-Based Composites Filled with Cotton, Jute and Kenaf Fibers
    • Jerzy Korol
    • Aleksander Hejna
    • Dorota Burchart-Korol
    • Jan Wachowicz
    2020 Full text Materials

    Composites containing natural fibers are considered environmentally friendly materials which is related to the reduced use of fossil fuels and the emission of carbon dioxide compared to petroleum-based polymers. Nevertheless, a complete evaluation of their environmental impact requires a broader view. This paper presents a carbon, ecological, and water footprints assessment of polypropylene-based composites filled with cotton, jute, and kenaf fibers based on a standardized European pallet (EUR-pallet) case study. Obtained results were compared with unmodified polypropylene and composite with glass fibers. Incorporation of 30 wt% of cotton, jute, and kenaf fibers into a polypropylene matrix reduced its carbon footprint by 3%, 18%, and 18%, respectively. Regarding the ecological footprint, an 8.2% and 9.4% reduction for jute and kenaf fibers were noted, while for cotton fibers, its value increased by 52%. For these footprints, the use of jute and kenaf fibers was more beneficial than glass fibers. Nevertheless, the application of natural fibers caused a 286%, 758%, and 891% drastic increase of water footprint of the final product, which was mainly affected by cultivation and irrigation of crops. Therefore, in a holistic view, the incorporation of natural fibers into the polypropylene matrix definitely cannot be impartially considered as an environmentally friendly solution.

  • Comparative DEM calculations of fracture process in concrete considering real angular and artificial spherical aggregates
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    2020 Full text ENGINEERING FRACTURE MECHANICS

    Artykuł omawia wyniki obliczeń numerycznych pękania dla betonu stosując metodę elementów dyskretnych (DEM). Beton był opisany jako materiał 4-fazowy i był poddany zginaniu. Zbadano wpływ kształtu kruszywa na proces pekania i na zalezność obciązenia od ugięcia. Wyniki dwuwymiarowe i trzywymiarowe porównano bezpośrednio z doświadczeniami. Wyniki pokazały duzy wpływ kształtu kruszywa na wyniki numeryczne.

  • Comparative Lipidomic Study of Human Milk from Different Lactation Stages and Milk Formulas
    • Weronika Hewelt-Belka
    • Dorota Garwolińska
    • Michał Młynarczyk
    • Agata Kot-Wasik
    2020 Full text Nutrients

    In this report, we present a detailed comparison of the lipid composition of human milk (HM) and formula milk (FM) targeting different lactation stages and infant age range. We studied HM samples collected from 26 Polish mothers from colostrum to 19 months of lactation, along with FM from seven brands available on the Polish market (infant formula, follow-on formula and growing-up formula). Lipid extracts were analysed using liquid chromatography coupled to high-resolution mass spectrometry (LC–Q-TOF–MS). We found that the lipid composition of FM deviates significantly from the HM lipid profile in terms of qualitative and quantitative differences. FM had contrasting lipid profiles mostly across brands and accordingly to the type of fat added but not specific to the target age range. The individual differences were dominant in HM; however, differences according to the lactation stage were also observed, especially between colostrum and HM collected in other lactation stages. Biologically and nutritionally important lipids, such as long-chain polyunsaturated fatty acids (LC-PUFAs) containing lipid species, sphingomyelines or ether analogues of glycerophosphoethanoloamines were detected in HM collected in all studied lactation stages. The observed differences concerned all the major HM lipid classes and highlight the importance of the detailed compositional studies of both HM and FM.

  • Comparative study of a bottoming SRC and ORC for Joule–Brayton cycle cooling modular HTR exergy losses, fluid-flow machinery main dimensions, and partial loads
    • Tomasz Kowalczyk
    • Janusz Badur
    • Paweł Ziółkowski
    2020 Full text ENERGY

    Energy conversion efficiency increase in power plants with high-temperature gas-cooled reactors via implementation of the bottoming cycle was investigated under nominal and minimal thermal load of a high-temperature reactor (HTR). Heat transfer surface area and turbine outlet volumetric flow rate in bottoming cycles was also investigated. Water and two low-boiling point working fluids (ammonia and ethanol) were analyzed. Analyzed thermodynamic cycles consisted of a closed Joule-Brayton cycle with helium as working medium, which was investigated in configurations with heat regeneration, compressor intercoolers, and in a simple design. Organic versus steam Rankine cycles were compared; low-boiling point fluids under supercritical conditions in some configurations provide higher cycle energy efficiency than the gas-steam cycle. Volumetric flow rates in the last turbine stages were reduced against the steam turbine to 38% and 0.8% with ethanol and ammonia, respectively. The steam Rankine cycle configuration provided the smallest heat transfer surface increase compared with the base cycle.

  • Comparative Study of Integer and Non-Integer Order Models of Synchronous Generator
    • Szymon Racewicz
    • Filip Kutt
    • Michał Michna
    • Łukasz Sienkiewicz
    2020 Full text ENERGIES

    This article presents a comparison between integer and non-integer order modelling of a synchronous generator, in the frequency domain as well as in the time domain. The classical integer order model was compared to one containing half -order systems. The half-order systems are represented in a Park d-q axis equivalent circuit as impedances modelled by half-order transmittances. Using a direct method based on the approximation of the half-order derivatives by the Grünwald–Letnikov definition, a state-space equation system was solved. For both models, a computational program written in Matlab software was used. For the purpose of time domain simulation, the machine models were connected to an electric load composed of an RL circuit. To validate and compare both models, simulation results of a three-phase short-circuit and a no-load voltage recovery were compared with corresponding measurements performed on a solid salient-pole synchronous generator of 125 kVA.

  • Comparing the permeability of human and porcine small intestinal mucus for particle transport studies
    • Lukasz Krupa
    • Balazs Bajka
    • Robert Staroń
    • Didier Dupont
    • Harjinder Singh
    • Krzysztof Gutkowski
    • Adam Macierzanka
    2020 Full text Scientific Reports

    The gastrointestinal mucus layer represents the last barrier between ingested food or orally administered pharmaceuticals and the mucosal epithelium. This complex gel structure plays an important role in the process of small intestinal absorption. It provides protection against hazardous particles such as bacteria but allows the passage of nutrients and drug molecules towards the intestinal epithelium. In scientific research, mucus from animal sources is usually used to simulate difficult-to-obtain human small intestinal mucus for investigating the intramucus transport of drug delivery systems or food nanoparticles. However, there is a lack of evidence the human mucus can be reliably substituted by animal counterparts for human-relevant transport models. In this report, a procedure for collecting human mucus has been described. More importantly, the permeability characteristics of human and porcine small intestinal mucus secretions to sub-micron sized particles have been compared under simulated intestinal conditions. Negatively charged, 500 nm latex beads were used in multiple-particle tracking experiments to examine the heterogeneity and penetrability of mucus from different sources. Diffusion of the probe particles in adult human ileal mucus and adult pig jejunal and ileal mucus revealed no significant differences in microstructural organisation or microviscosity between the three mucus types (P > 0.05). In contrast to this interspecies similarity, the intraspecies comparison of particle diffusivity in the mucus obtained from adult pigs vs. 2-week old piglets showed better penetrability of the piglet mucus. The mean Stokes–Einstein viscosity of the piglet jejunal mucus was approx. two times lower than the viscosity of the pig jejunal mucus (P < 0.05). All mucus structures were also visualised by scanning electron microscopy. This work validates the use of porcine small intestinal mucus collected from fully-grown pigs for studying colloidal transport of sub-micron sized particles in mucus under conditions mimicking the adult human small intestinal environment.

  • Comparing traffic intensity estimates employing passive acoustic radar and microwave Doppler radar sensor
    • Andrzej Czyżewski
    2020 Journal of the Acoustical Society of America

    The purpose of our applied research project is to develop an autonomous road sign with built-in radar devices of our design. In this paper, we show that it is possible to calibrate the acoustic vector sensor so that it can be used to measure traffic volume and count the vehicles involved in the traffic through the analysis of the noise emitted by them. Signals obtained from a Doppler radar are used as a reference source. Although the acoustical vector sensor (AVS), being the embodiment of acoustic radar, has a lower accuracy than Doppler radar in vehicle counting and cannot measure the vehicle speed with the same precision has certain advantages over the Doppler sensor. Namely, it does not emit any signals, it is not susceptible to electromagnetic interferences, and it allows for further analysis of audio signals, such as assessment of the road surface state (e.g., wet/dry). The acoustic radar employing AVS we developed is a new proposition of the acoustic method for road traffic monitoring. Our research also allowed a comparison of the efficiency of both methods, namely microwave and acoustic ones. In this paper, we also provide a short review of previous publications on the project.

  • Comparison of Cadmium Cd2+ and Lead Pb2+ Binding by Fe2O3@SiO2‐EDTA Nanoparticles – Binding Stability and Kinetic Studies
    • Amanda Kulpa
    • Jacek Ryl
    • Grzegorz Skowierzak
    • Adrian Koterwa
    • Grzegorz Schroeder
    • Tadeusz Ossowski
    • Paweł Niedziałkowski
    2020 Full text ELECTROANALYSIS

    This study describes the synthesis and characterization of ethylenediaminetetraacetic acid (EDTA) functionalized magnetic nanoparticles of 20 nm in size – Fe3O4@SiO2‐EDTA – which were used as a novel magnetic adsorbent for Cd(II) and Pb(II) binding in aqueous medium. These nanoparticles were obtained in two‐stage synthesis: covering by tetraethyl orthosilicate and functionalization with EDTA derivatives. Nanoparticles were characterized using TEM, FT‐IR, and XPS methods. Metal ions were detected under optimized experimental conditions using Differential Pulse Anodic Stripping Voltammetry (DPASV) and Hanging Mercury Drop Electrode (HDME) techniques. We compared the ability of Fe3O4@SiO2‐EDTA to bind cadmium and lead in concentration of 553.9 μg L−1 and 647.5 μg L−1, respectively. Obtained results show that the adsorption rate of cadmium binding was very high. The equilibrium for Fe3O4@SiO2‐EDTA‐Cd(II) was reached within 19 min while for the Fe3O4@SiO2‐EDTA‐Pb(II) was reached within 25 minutes. About 2 mg of nanoparticles was enough to bind 87.5 % Cd(II) and 54.1 % Pb(II) content. In the next step the binding capacity of Fe3O4@SiO2‐EDTA nanoparticles was determined. Only 1.265 mg of Fe3O4@SiO2‐EDTA was enough to bind 96.14 % cadmium ions while 5.080 mg of nanoparticles bound 40.83 % lead ions. This phenomenon proves that the studied nanoparticles bind Cd(II) much better than Pb(II). The cadmium ions binding capacity of Fe3O4@SiO2‐EDTA nanoparticles decreased during storage in 0.5 M KCl solution. Two days of Fe3O4@SiO2‐EDTA storage in KCl solution caused the 32 % increase in the amount of nanoparticles required to bind 60 % of cadmium while eight‐days storage caused further increase to 328 %. The performed experiment confirmed that the storage of nanoparticles in solution without any surfactants reduced their binding capacity. The best binding capacity was observed for the nanoparticles prepared directly before the electrochemical measurements.

  • Comparison of near infrared spectroscopy (NIRS) and near-infrared transillumination-backscattering sounding (NIR-T/BSS) methods
    • Agnieszka Gruszecka
    • Marcin Gruszecki
    • Patric J. Neary
    • Jyotpal Singh
    • Taylor Teckchandani
    • Monika Waskow
    • Magdalena Wszedybyl-Winklewska
    • Wojciech Gumiński
    • Andrzej F. Frydrychowski
    • Jacek Rumiński
    • Piotr Lass
    • Gregory Kratzig
    • Paweł J. Winklewski
    2020 Full text Scientific Reports

    The aim of the study was to compare simultaneously recorded a NIR-T/BSS and NIRS signals from healthy volunteers. NIR-T/BSS is a device which give an ability to non-invasively detect and monitor changes in the subarachnoid space width (SAS). Experiments were performed on a group of 30 healthy volunteers (28 males and 2 females, age 30.8 ± 13.4 years, BMI = 24.5 ± 2.3 kg/m2). We analysed recorded signals using analysis methods based on wavelet transform (WT) for the wide frequency range from 0.0095 to 2 Hz. Despite the fact that both devices use a similar radiation source both signals are distinct from each other. We found statistically significant differences for WT amplitude spectra between both signals. Additionally, we showed different relationships of both signals to blood pressure. Collectively, based on the present findings and those of previous studies, we can conclude that the combination of NIR-T/BSS or NIRS signals and time–frequency analysis opens new frontiers in science, and give possibility to understand and diagnosis of various neurodegenerative and ageing related diseases to improve diagnostic procedures and patient prognosis.

  • Comparison of sound of organ pipes in contemporary and historical instruments
    • Marta Kalman
    • Damian Koszewski
    • Bartłomiej Mróz
    2020

    The aim of this research is to examine the differences in the timbre of organ pipes’ sound between a historical and a contemporary organ instrument. The historical instrument is the Oliwa organ from Gdansk, Poland, and the contemporary one is from Kartuzy, Poland. Recordings are made of single notes played by an open labial pipe that belongs to the Principal rank. The analyses and comparison of several sound features compatible with audio descriptors defined in MPEG-7 standard are performed in the MATLAB environment. The influence of the distance between the microphone and the sound source on sound features is also examined, in order to judge whether the comb filter appears in close distances from the sound source.

  • Comparison of the Physical and Sensory Properties of Hybrid Citrus Fruit Jaffa® Sweetie in Relation to the Parent Fruits
    • Martyna Lubinska-Szczygeł
    • Żaneta Polkowska
    • Tomasz Dymerski
    • Shela Gorinstein
    2020 Full text MOLECULES

    In the presented study, an overall Jaffa sweetie evaluation was made to find a correlation between Citrus grandis Osbeck × Citrus paradisi Macf. and its parent fruits’ (Citrus grandis Osbeck, Citrus paradisi Macf.) properties. Based on the sensory analysis, it was found that the taste and aroma of the new hybrid fruit are close to pummelo. By the use of chromatographic analysis, the selected monoterpenes present in the fruits were quantified. α-terpineol was typed as the main monoterpene compound in the headspace of sweetie and grapefruit, with the concentrations: 20.96 and 87.9 µg/g, respectively. In turn, γ-terpinene was chosen as the most important monoterpene determining the flavor of sweetie fruit. Based on two-dimensional gas chromatography (GC × GC-TOF-MS) and principal component analysis (PCA) of the data, several volatile compounds were associated with analyzed fruits’ aroma. Jaffa Sweetie is the hybrid fruit with sensory properties similar to pummelo with a higher content of monoterpenes, which improves its health benefits compared to the parent fruit. The research presents an instrumental method for assessing the aroma properties of the fruit as a reference method for sensory analysis, commonly used in the industry.

  • Comparison of two methods of sound extraction from guitar string video recordings
    • Marta Stefaniak
    • Andrzej Czyżewski
    2020

    A comparison of two sound extraction methods from guitar string video recordings is presented in the paper. A brief overview of highframe rate camera technology and possible applications are included. The method using the image analysis from two such cameras is presented. The cameras are placed at the angle of 90 degrees for recording the image in three planes. The results achieved with the setup proposed by ourselvesare comparedto the results of recording with a single highframe rate camera used for the Visual Microphone method developed by scientists from MIT. Spectrograms and signal spectra of recordings were compared and discussed, revealing that both methods of sound extraction from video brought the ability to reproduce sound, but with some distortions.Finally, the options for future experiments are considered.

  • Compensation of supply current harmonics, reactive power, and unbalanced load current balance in the closed-loop control of a shunt active power filter
    • Agata Bielecka
    • Daniel Wojciechowski
    2020 Full text Zeszyty Naukowe Akademii Morskiej w Szczecinie

    This paper presents the compensation tasks performed by a shunt active power filter, including compensation of harmonic currents, reactive power, and an unbalanced load current. The paper demonstrates novel control of the shunt active power filter in a closed-loop system. The control algorithm was verified by performing simulations and compared the simulated results with those obtained in an open-loop control system. All simulations were conducted in the PLECS program using a control algorithm written in C programming language.

  • Competencies of graduates as future labour market participants – preliminary study
    • Małgorzata Gawrycka
    • Justyna Kujawska
    • Michał Tomasz Tomczak
    2020 Full text Economic Research-Ekonomska Istrazivanja

    The aim of article is to examine and compare the views of employers and future employees on the desirable competencies of the potential labour market participants. The applied research method is a combination of qualitative and quantitative methods – interviews conducted among recruiters (representing potential employers) and a survey of university graduates (future employees). The study shows that both the Polish graduates and the employers identify the deficits of professional competencies. The differences of opinions were related to their assessment of generic competencies, the deficits of which were pointed to by the interviewed recruiters, who described them at the same time as fundamental to obtaining the employment. Meanwhile, the graduates assessed their generic competencies as the highest. According to the recruiters, the future employees lack also practical experience. On the other hand, the employers believe that the graduates are not prepared to using the possessed theoretical knowledge in practice. It should be noted, however, that employers perceive a great potential for the development of graduate competencies, which, together with acquiring practical experience, will probably lead to the narrowing of the competence gap.

  • Complex Predictive Solution for Computerized Processes in Tire Industry
    • Jan Piesik
    • Kazimierz Kosmowski
    2020 Full text

    Following increasing market needs of productivity, cost reduction and safety requirements, computerized industry are faced to finding optimum between economic aspects of business and safety-related risk management. Modern factories equipped with computerized processes and extended diagnostic tools to support operator do not often use of all information’s which comes from the equipment. Some of the relations between the events are also omitted or neglected. Authors after analyzing the defects of modern production lines with batch production, noticed a correlation between the defects and the historical information registered by the supervisory system controlling the production process. The problem is that with the multitude of appearing information, they are not analyzed on an ongoing basis. This article presents a new approach to increase machinery reliability, safety and quality increase through predictive data analysis.

  • Comprehensive Evaluation of the Biological Properties of Surface-Modified Titanium Alloy Implants
    • Piotr Piszczek
    • Aleksandra Radtke
    • Michalina Ehlert
    • Tomasz Jędrzejewski
    • Alicja Sznarkowska
    • Beata Sadowska
    • Michał Bartmański
    • Yasar Kemal Erdogan
    • Batur Ercan
    • Waldemar Jędrzejczyk
    2020 Full text Journal of Clinical Medicine

    An increasing interest in the fabrication of implants made of titanium and its alloys results from their capacity to be integrated into the bone system. This integration is facilitated by different modifications of the implant surface. Here, we assessed the bioactivity of amorphous titania nanoporous and nanotubular coatings (TNTs), produced by electrochemical oxidation of Ti6Al4V orthopedic implants’ surface. The chemical composition and microstructure of TNT layers was analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). To increase their antimicrobial activity, TNT coatings were enriched with silver nanoparticles (AgNPs) with the chemical vapor deposition (CVD) method and tested against various bacterial and fungal strains for their ability to form a biofilm. The biointegrity and anti-inflammatory properties of these layers were assessed with the use of fibroblast, osteoblast, and macrophage cell lines. To assess and exclude potential genotoxicity issues of the fabricated systems, a mutation reversal test was performed (Ames Assay MPF, OECD TG 471), showing that none of the TNT coatings released mutagenic substances in long-term incubation experiments. The thorough analysis performed in this study indicates that the TNT5 and TNT5/AgNPs coatings (TNT5—the layer obtained upon applying a 5 V potential) present the most suitable physicochemical and biological properties for their potential use in the fabrication of implants for orthopedics. For this reason, their mechanical properties were measured to obtain full system characteristics.

  • Compressive Sensing Approach to Harmonics Detection in the Ship Electrical Network
    • Beata Palczynska
    • Romuald Maśnicki
    • Janusz Mindykowski
    2020 Full text SENSORS

    The contribution of this paper is to show the opportunities for using the compressive sensing (CS) technique for detecting harmonics in a frequency sparse signal. The signal in a ship’s electrical network, polluted by harmonic distortions, can be modeled as a superposition of a small number of sinusoids and the discrete Fourier transform (DFT) basis forms its sparse domain. According to the theory of CS, a signal may be reconstructed from under-sampled incoherent linear measurements. This paper highlights the use of the discrete Radon transform (DRT) techniques in the CS scheme. In the reconstruction algorithm section, a fast algorithm based on the inverse DRT is presented, in which a few randomly sampled projections of the input signal are used to correctly reconstruct the original signal. However, DRT requires a very large set of measurements that can defeat the purpose of compressive data acquisition. To acquire the wideband data below the Nyquist frequency, the K-rank-order filter is applied in the sparse transform domain to extract the most significant components and accelerate the convergence of the solution. While most CS research efforts focus on random Gaussian measurements, the Bernoulli matrix with different values of the probability of ones is applied in the presented algorithm. Preliminary results of numerical simulation confirm the effectiveness of the algorithm used, but also indicate its limitations. A significant advantage of the proposed approach is the speed of analysis, which uses fast Fourier transform (FFT) and inverse FFT (IFFT) algorithms widely available in programming environments. Moreover, the data processing algorithm is quite simple, and therefore memory usage and burden of the data processing load are relatively low.

  • Computational Fluid Dynamics Simulation of Gas–Liquid Multiphase Flow in T-junction for CO2 Separation
    • Sylwia Wrzesień
    • Paweł Madejski
    • Paweł Ziółkowski
    2020 Prace Naukowe Wydziału Architektury Politechniki Wrocławskiej

    The article presents the results of a computational fluid dynamics (CFD) analysis of gas-liquid multiphase flow. The simulation was conducted using CFD code and the Euler–Euler approach. The presented study relates to the non–reactive, steady-state, turbulent flow of water and carbon dioxide mixture in a 3D pipe. Separation phenomenon between phases is observed. The solution was obtained using a mixture model. Different values of carbon dioxide volume fraction were taken into account in the analysis of the results. The analysed cases were compared thanks to the obtained calculations results. The main purpose of the simulations was to show streamlines, velocity, pressure, and volume fraction distribution that could be useful in developing pipeline systems in many industrial applications, especially for CO2 separator.

  • Computationally-efficient design optimisation of antennas by accelerated gradient search with sensitivity and design change monitoring
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2020 Full text IET Microwaves Antennas & Propagation

    Electromagnetic (EM) simulation tools are of primary importance in the design of contemporary antennas. The necessity of accurate performance evaluation of complex structures is a reason why the final tuning of antenna dimensions, aimed at improvement of electrical and field characteristics, needs to be based on EM analysis. Design automation is highly desirable and can be achieved by coupling EM solvers with numerical optimisation routines. Unfortunately, its computational overhead may be impractically high for conventional algorithms. This study proposes an efficient gradient search algorithm with numerical derivatives. The acceleration of the optimisation process is obtained by means of the two mechanisms developed to suppress some of finite-differentiation-based updates of the antenna response sensitivities that involve monitoring and quantifying the gradient changes as well as design relocation between the consecutive algorithm iterations. Both methods considerably reduce the need for finite differentiation, leading to significant computational savings. At the same time, excellent reliability and repeatability is maintained, which is demonstrated through statistics over multiple algorithm runs with random initial designs. The proposed approach is validated using a benchmark set of wideband antennas. The proposed algorithm is competitive to both the reference trust-region algorithm as well as its recently reported accelerated versions.

  • Computations of the least number of periodic points of smooth boundary-preserving self-maps of simply-connected manifolds
    • Grzegorz Graff
    • Jerzy Jezierski
    • Adrian Myszkowski
    2020 Topological Methods in Nonlinear Analysis

    Let $r$ be an odd natural number, $M$ a compact simply-connected smooth manifold, $\dim M\geq 4$, such that its boundary $\partial M$ is also simply-connected. We consider $f$, a $C^1$ self-maps of $M$, preserving $\partial M$. In [G. Graff and J. Jezierski, Geom. Dedicata 187 (2017), 241-258] the smooth Nielsen type periodic number $D_r(f;M,\partial M)$ was defined and proved to be equal to the minimal number of $r$-periodic points for all maps preserving $\partial M$ and $C^1$-homotopic to $f$. In this paper we demonstrate a purely combinatorial method of calculation of the invariant and illustrate it in various cases.

  • Computed tomography indicators of cerebral microperfusion improve long term after carotid stenting in symptomatic patients
    • Paweł J. Winklewski
    • Mariusz Kaszubowski
    • Grzegorz Halena
    • Agnieszka Sabisz
    • K Chojnicki
    • Jaroslaw Dzierzanowski
    • Maciej Piskunowicz
    • N. Kurhaluk
    • Edyta Szurowska
    • Arkadiusz Szarmach
    2020 Full text Acta Biochimica Polonica

    OBJECTIVES: We tested the hypothesis that computed tomography (CT) perfusion markers of cerebral microcirculation would improve 36 months after internal carotid artery stenting for symptomatic carotid stenosis while results obtained 6-8 weeks after the stenting procedure would yield a predictive value. METHODS: We recruited consecutive eligible patients with >70% symptomatic carotid stenosis with a complete circle of Willis and normal vertebral arteries to the observational cohort study. We detected changes in the cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP) and permeability surface area-product (PS) before and after carotid stenting. We have also compared the absolute differences in the ipsilateral and contralateral CT perfusion markers before and after stenting. The search for regression models of "36 months after stenting" results was based on a stepwise analysis with bidirectional elimination method. RESULTS: A total of 34 patients completed the 36 months follow-up (15 females, mean age of 69.68±S.D. 7.61 years). At 36 months after stenting, the absolute values for CT perfusion markers had improved: CBF (ipsilateral: +7.76%, contralateral: +0.95%); CBV (ipsilateral: +5.13%, contralateral: +3.00%); MTT (ipsilateral: -12.90%; contralateral: -5.63%); TTP (ipsilateral: -2.10%, contralateral: -4.73%) and PS (ipsilateral: -35.21%, contralateral: -35.45%). MTT assessed 6-8 weeks after stenting predicted the MTT value 36 months after stenting (ipsilateral: R2=0.867, contralateral R2=0.688). CONCLUSIONS: We have demonstrated improvements in CT perfusion markers of cerebral microcirculation health that persist for at least 3 years after carotid artery stenting in symptomatic patients. MTT assessed 6-8 weeks after stenting yields a predictive value.

  • Concentration of Potentially Bioactive Compounds in Italian Extra Virgin Olive Oils from Various Sources by Using LC-MS and Multivariate Data Analysis
    • Anna Różańska
    • Marina Russo
    • Francesco Cacciola
    • Fabio Salafia
    • Żaneta Polkowska
    • Paola Dugo
    • Luigi Mondello
    2020 Full text Foods

    High quality extra virgin olive oils represent an optimal source of nutraceuticals. The European Union (EU) is the world’s leading olive oil producer, with the Mediterranean region as the main contributor. This makes the EU the greatest exporter and consumer of olive oil in the world. However, small olive oil producers also contribute to olive oil production. Beneficial effects on human health of extra virgin olive oil are well known, and these can be correlated to the presence of vitamin E and phenols. Together with the origin of the olives, extraction technology can influence the chemical composition of extra virgin olive oil. The aim of this study was to investigate the concentration of potentially bioactive compounds in Italian extra virgin olive oils from various sources. For this purpose, vitamin E and phenolic fractions were characterized using high-performance liquid chromatography (HPLC) coupled with fluorescence, photodiode array and mass spectrometry detection in fifty samples of oil pressed at industrial plants and sixty-six samples of oil produced in low-scale mills. Multivariate statistical data analysis was used to determine the applicability of selected phenolic compounds as potential quality indicators of extra virgin olive oils.

  • Concept of a swirling diffuser in batch blending tanks
    • Wojciech Artichowicz
    • Jerzy Sawicki
    2020 Full text CHINESE JOURNAL OF CHEMICAL ENGINEERING

    The mixing of two or more components belongs to the category of the most common unit operations, both in technology and in nature. One particular version is homogenization (blending), the effectivity of which is strongly related to the blending time. Among many differentiated individual solutions of mixing systems used in blenders, one should distinguish the class of agitators with diffusers. An analysis of the character of the velocity field during a blending chamber operation leads to the conclusion that it would be of avail to outfit a straight diffuser with different setup of elbows. In consequence, the vertical direction of the inflowing fluid stream would be changed into the horizontal direction of the outflowing stream, which should intensify the blending process. The concept has been verified experimentally, making use of the tracer methodology. The obtained results confirmed the theoretical conclusion, that the blending time for the swirling-diffuser was shorter than for the classical straight one.

  • Concrete Compressive Strength Under Changing Environmental Conditions During Placement Processes
    • Andrzej Ambroziak
    • Patryk Ziółkowski
    2020 Full text Materials

    The technological process of concrete production consists of several parts, including concrete mix design, concrete mix production, transportation of fresh concrete mix to a construction site, placement in concrete framework, and curing. Proper execution of these steps provides good quality concrete. Some factors can disturb the technological process, mainly temperature and excessive precipitation. Changing daily temperature and rainfall during fabrication, transportation, and placement can shape not only the properties of the concrete mix but also the compressive strength of hardened concrete. In this paper, we tried to answer the question of how temperature and precipitation affect concrete production. The scope of this study was to determine the change of compressive strength of the hardened concrete in a specific period for selected concrete mix recipes, taking into account changing daily temperature and precipitation magnitude. The investigated concrete mixes concrete compressive strength beyond that of the concrete grade, termed "concrete superstrength.” This concrete post limiting behaviour of concrete is also discussed.

  • CONCRETE MIX DESIGN USING SIMPLE EQUATIONS
    • Hakim Abdelgader
    • Ramadan Suleiman
    • Abdalla Adam
    • Jamal Khatib
    2020 Full text BAU Journal - Science and Technology

    The behaviour of concrete, whether fresh or har dened, depends basically on the beha viour of its components and the r elationship between them, ther efore, obtaining a concr ete with cer tain pr operties depends fundamentally on the concr ete mix design. Concr ete mix design gener ally includes two main steps: 1-Selection of the main components suitable for the concr ete (cement, aggr egate, water , and additiv es); 2-Determination of mor e economical mix r atios t o fulfil the workability , str ength and efficiency requirements. Curr ently, ther e ar e many international methods locally appr oved for mix designs. The y are all r elated t o each other , the y giv e r elatively the same quantities of the mix components and the y are all capable of pr oviding a good concr ete mix. It is impor tant t o consider that these methods giv e approximate quantities which should be check ed b y experimental mix es in or der t o obtain r esults suitable for the r equirements of the local envir onment and local materials. The A CI and BS methods ar e the most commonly used. Both of these methods depend on gr aphs and standar d tables deriv ed fr om pr evious research experience and actual concr ete pr oduction as well as studies of the pr operties of the materials used. This paper illustr ates a new appr oach for concr ete mix design named as: “Double Coating Method”, which is curr ently used in some r esearch centers in the r epublic of P oland and was r ecently applied in the laboratories of the Civil Engineering Depar tments in the Univ ersities of T ripoli and Benghazi in Lib ya. This paper describes experiment in which 24 mixtur es wer e used t o assess the usefulness of this technique for problem of pr oportioning concr ete mixtur es in gener

  • Concrete-filled FRP tubular members in marine and bridge structures
    • Marcin Abramski
    2020

    Concrete core of the concrete-filled tubes (CFTs) with circular cross-section is in the case of an axial compression subjected to a spatial state of compressive stresses. This state leads to enhancement in the concrete strength. The enhancement is utilized in Eurocode 4 design procedures for CFSTs (i.e. CFTs with tube made of steel). The structural design of CFFTs (i.e. CFTs with tube made of Fibre Reinforced Polymer - FRP) is normalized in LFRD Guide Specifications released by AASHTO in 2012. The mathematical model of confined concrete adopted in these design guidelines has also regard to the concrete strength enhancement. The differences between the both models of triaxially compressed concrete are discussed in the paper. The latter model was used in an author’s computer program developed to calculate the load-carrying capacity of 15 CFFT columns which were previously experimentally investigated in the axial and eccentric compression. The calculated and experimentally obtained capacities are compared. The auctorial program predicted the columns load-carrying capacity with a safety margin of 33% on average.

  • Conductivity, structure, and thermodynamics of Y2Ti2O7–Y3NbO7 solid solutions
    • Piotr Winiarz
    • Aleksandra Mielewczyk-Gryń
    • Kristina Lilova
    • Sebastian Wachowski
    • Tamilarasan Subramani
    • Mykola Abramchuk
    • Ewa Dzik
    • Alexandra Navrotsky
    • Maria Gazda
    2020 Full text DALTON TRANSACTIONS

    The defect fluorite yttrium niobate Y3NbO7 and pyrochlore yttrium titanate Y2Ti2O7 solid solutions have been synthesized via a solid state synthesis route. The resulting stoichiometry of the oxides is Y2+xTi2−2xNbxO7, where x = 0 to x = 1. All of the samples were single-phase; however, for those with a predominant fluorite phase, a small amount of additional pyrochlore phase was detected. The volume of the solid solution unit cells linearly increases with increase in yttrium niobate content. The water uptake increases with (x) and the protonic defect concentration reaches almost 4.5 × 10−3 mol mol−1 at 300 °C. The calculated enthalpy of formation from oxides suggests strong stability for all of the compositions, with the values of enthalpy ranging from −84.6 to −114.3 kJ mol−1 . The total conductivity does not have a visible dependence on Y3NbO7 content. For each compound, the total conductivity is higher in wet air. Interestingly, for samples where x < 0.5, the ratio of conductivity in hydrogen to air increases with increasing temperature, while for x > 0.5, the trend is the opposite.

  • Conjugates of Ciprofloxacin and Levofloxacin with Cell-Penetrating Peptide Exhibit Antifungal Activity and Mammalian Cytotoxicity
    • Natalia Ptaszyńska
    • Katarzyna Gucwa
    • Katarzyna Olkiewicz
    • Mateusz Heldt
    • Marcin Serocki
    • Anna Stupak
    • Dorota Martynow
    • Dawid Dębowski
    • Agata Gitlin-Domagalska
    • Jan Lica
    • Anna Łęgowska
    • Sławomir Milewski
    • Krzysztof Rolka
    2020 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Seven conjugates composed of well-known fluoroquinolone antibacterial agents, ciprofloxacin (CIP) or levofloxacin (LVX), and a cell-penetrating peptide transportan 10 (TP10-NH2) were synthesised. The drugs were covalently bound to the peptide via an amide bond, methylenecarbonyl moiety, or a disulfide bridge. Conjugation of fluoroquinolones to TP10-NH2 resulted in congeners demonstrating antifungal in vitro activity against human pathogenic yeasts of the Candida genus (MICs in the 6.25 – 100 μM range), whereas the components were poorly active. The antibacterial in vitro activity of most of the conjugates was lower than the activity of CIP or LVX, but the antibacterial effect of CIP-S-S-TP10-NH2 was similar to the mother fluoroquinolone. Additionally, for two representative CIP and LVX conjugates, a rapid bactericidal effect was shown. Compared to fluoroquinolones, TP10-NH2 and the majority of its conjugates generated a relatively low level of reactive oxygen species (ROS) in human embryonic kidney cells (HEK293) and human myeloid leukemia cells (HL-60). The conjugates exhibited cytotoxicity against three cell lines, HEK293, HepG2 (human liver cancer cell line), and LLC-PK1 (old male pig kidney cells), with IC50 values in the 10 – 100 μM range and hemolytic activity. The mammalian toxicity was due to the intrinsic cytoplasmic membrane disruption activity of TP10-NH2 since fluoroquinolones themselves were not cytotoxic. Nevertheless, the selectivity index values of the conjugates, both for the bacteria and human pathogenic yeasts, remained favourable.

  • Considerations about the applicability of the Reynolds equation for analyzing high-speed near field levitation phenomena
    • Noël Brunetière
    • Michał Wodtke
    2020 Full text JOURNAL OF SOUND AND VIBRATION

    equation for analyzing near field levitation (NFL) phenomena. Two separate approaches were developed, experimentally verified, and applied to meet the research objective. One was based on the Reynolds equation and the other was based on general conservation equations for fluid flow solved using computational fluid dynamic (CFD). Comparing the calculation results revealed that, for certain operating conditions, differences in the predicted system parameters appear. It was proven that both the Reynolds and Helmholtz numbers define border operating conditions for the applicability of the Reynolds equation to analyze NFL problems.

  • Constitutive Modelling of Knitted Abdominal Implants in Numerical Simulations of Repaired Hernia Mechanics
    • Agnieszka Tomaszewska
    • Daniil Reznikov
    • Czesław Szymczak
    • Izabela Lubowiecka
    2020 Full text

    The paper presents a numerical approach to describe mechanical behavior of anisotropic textile material, which is a selected abdominal prosthesis. Two constitutive nonlinear concepts are compared. In the first one the material is considered composed from two families of threads (dense net model) and in the second one the material is homogeneous but anisotropic (as proposed by Gassel, Ogden, Holzapfel). Parameters of both models are identified based on experimental tensile tests (uni-axial and bi-axial, simple and cyclic). The constitutive relations are applied in numerical membrane model of the prosthesis applied in the abdominal wall. Its mechanical responses to the pressure loading has been compared, also to deflection experimentally observed in physical model of the operated hernia of the same geometry. The authors find that both constitutive models properly describe the implant’s mechanics, but further studies are needed to possibly approach the outcome of hyperelastic anisotropic model to experimental results obtained for synthetic knit mesh

  • Constructing a Dataset of Speech Recordingswith Lombard Effect
    • Dawid Weber
    • Szymon Zaporowski
    • Daniel Korzekwa
    2020

    Thepurpose of therecordings was to create a speech corpus based on the ISLEdataset, extended with video and Lombard speech. Selected from a set of 165sentences, 10, evaluatedas having thehighest possibility to occur in the context ofthe Lombard effect,were repeated in the presence of the so-called babble speech to obtain Lombard speech features. Altogether,15speakers were recorded, and speech parameterswere calculated and analyzed. First, a brief summary of the research related to the Lombard effect is given. Then, therecording studiocharacteristicsand the equipment utilizedfor recordings areshown.Examples of analyses are included,concerning both non-Lombard and Lombard speech. Finally, a recapitulation of experiments performedalong with further researchplans is given.The link to the data is also provided.

  • Consumerism in Poland – a fact or a myth?
    • Anna Drapińska
    2020

    Purpose Consumerism, understood as excessive consumption, poses a vital problem in the world, and requires taking appropriate steps and actions in individual countries depending on the extent and nature of this phenomenon. The purpose of this paper is to examine the phenomenon of consumerism in Poland, with partial reference to other EU countries and to answer the question whether there is consumerism as such in Poland. Design/methodology/approach Data from secondary sources were used for the purpose of the paper. The study is based on statistical data analysis (Eurostat, Polish Statistical Main Office) and surveys of national experts, institutions and research agencies. The time span of the data observed extended from 2010 to 2018. The applied method can be defined as a descriptive statistics method with elements of quantitative analysis. Findings The study shows that the phenomenon of consumerism in Poland is not yet developed to the extent comparable to Western European countries. With the basic needs of the majority of average Polish households consuming the major part of their income, combined with the necessity to rationalize spending, which is forced by social and economic situation, consumers are more inclined to reasonably manage their resources. Polish consumers are still trying to catch up and meet their needs at a level similar to that in highly developed countries. Nevertheless, one can observe some symptoms of consumerist behaviour, e.g. spending on pleasure and entertainment prevails over saving, buying unnecessary things, or pleasure shopping. Originality/value Until now, the subject of consumerism in Poland was tackled very rarely and in a fragmentary way. No answer was given to the question whether there is consumerism in Poland and what is the level of its advancement. This paper is an attempt to identify this phenomenon based on available secondary sources. In addition it has been shown that statistics indicating the fifth place of Poland in Europe in terms of food waste are 'best estimates' mainly based on 2006 data from Eurostat and unfortunately no data were available from Poland.

  • Contact force network evolution in active earth pressure state of granular materials: photo‑elastic tests and DEM
    • Leśniewska Danuta
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    • M. Pietrzak
    2020 Full text GRANULAR MATTER

    Artykuł omawia ewolucję sieci sił kontaktowych w materiałach granulowanych podczas quasi-statycznego stanu aktywnego. Doświadczenia foto sprężyste zostały wykonane dla kulek szklanych. Doświadczenia zostały symulowane stosując metodę elementów dyskretnych (DEM). Model DEM prawidłowo przewidział strukturę sił kontaktowych i ich wielkość, lokalizację odkształceń oraz obszary zmian fazowych.

  • Contamination of Arctic Lakes with Persistent Toxic PAH Substances in the NW Part of Wedel Jarlsberg Land (Bellsund, Svalbard)
    • Sara Lehmann-konera
    • Ruman Marek
    • Łukasz Franczak
    • Żaneta Polkowska
    2020 Full text Water

    The expansion of glacier‐free areas in polar regions favours the appearance of lakes in the non‐glaciated parts of glacier basins. This paper presents the differentiation of organic compound concentrations in fifty‐four Arctic lakes collected in four locations (Logne Valley, in the vicinity of the Scott, Renard and Antonia glaciers). We cover meteorological measurements, chemical analysis of sixteen dioxin‐like compounds (Polycyclic Aromatic Hydrocarbons (PAHs)), formaldehyde (HCHO), sum parameters of phenolic compounds (Σphenols) and dissolved organic carbon (DOC). The most contaminated with PAH compounds were lakes exposed to the influence of the Greenland Sea (Logne Valley lakes) and to the prevailing winds (Scott and Renard lakes). Interpretation of the PAH compounds results allowed for identification of pyrogenic sources as the main sources of PAH compounds in the year 2012. The highest levels of HCHO and Σphenols were observed for the Scott lakes, while the highest DOC levels were noted in Antonia lakes.

  • Contemporary architecture within the context of architectural education
    • Agnieszka Malinowska
    • Karolina Taraszkiewicz
    2020 Full text World Transactions on Engineering and Technology Education

    Analysed in this article are the diploma projects of students of architecture in European countries. The aim was to examine how students approach an important issue related to sustainable development, i.e. the integration of newly designed architecture into the existing historical, cultural and natural context. The rational use and protection of the environment requires the skilful shaping of urbanised space. Many changes in the surrounding space, which result from the work of architectural engineers, have a huge impact on the quality of this space. Special emphasis was placed on creating methods for educating future professional engineer architects to understand the need for the proper coexistence of newly designed urban and architectural solutions within the existing historical, cultural and natural context, as well as having the skills to create such solutions.

  • Contextual ontology for tonality assessment
    • Wojciech Waloszek
    • Nina Rizun
    2020 Full text Procedia Computer Science

    classification tasks. The discussion focuses on two important research hypotheses: (1) whether it is possible to construct such an ontology from a corpus of textual document, and (2) whether it is possible and beneficial to use inferencing from this ontology to support the process of sentiment classification. To support the first hypothesis we present a method of extraction of hierarchy of contexts from a set of textual documents and encoding this hierarchy into a multi-level contextual ontology. To support the second hypothesis, we present a method of reasoning from the ontology, and results of experimental verification, which show that use of this reasoning method can increase accuracy of sentiment classification for longer text documents

  • Control of nonlinear and linearized model of self-balancing electric motorcycle
    • Adam Wonia
    • Michał Wonia
    • Robert Piotrowski
    2020 Full text

    Self-Balancing Electric Motorcycle (SBEM) is a dynamic and nonlinear electro-mechanical system. In this paper, the process of mathematical modelling and line-arization of SBEM is presented. The model of the control system in Matlab envi-ronment is implemented. The control system using the PID controller is designed. The operation of particular structures of the PID controller on the simulation model is compared. Due to simulation research, the most appropriate structure and parameters of the PID controller are chosen.

  • Convenient and Efficient Synthesis of Functionalized 2-Sulfenylindoles
    • Justyna Doroszuk
    • Mateusz Musiejuk
    • Bartosz Jędrzejewski
    • Juliusz Walczak
    • Dariusz Witt
    2020 Full text Materials

    A simple, efficient, and practical sulfenylation at the C2 position of N-tosylindoles under mild conditions was developed. The designed transformation is based on the reaction of N-tosylindoles with BuLi and S-alkyl, and S-aryl phosphorodithioates or thiotosylates to produce 2-sulfenylindoles in moderate to high yields. The presence of additional hydroxy, carboxy, or amino functionalities did not disturb the formation of products

  • Convergence of Monte Carlo algorithm for solving integral equations in light scattering simulations
    • Maciej Kraszewski
    • Jerzy Pluciński
    2020 Full text OPTICA APPLICATA

    The light scattering process can be modeled mathematically using the Fredholm integral equation. This equation is usually solved after its discretization and transformation into the system of algebraic equations. Volume integral equations can be also solved without discretization using the Monte Carlo (MC) algorithm, but its application to the light scattering simulations has not been sufficiently studied. Here we present implementation of this algorithm for one- and three-dimensional light scattering computations and discuss its applicability in this field. We show that the MC algorithm can provide valid and accurate results but, due to its convergence properties, it might be difficult to apply for problems with large volumes or refractive indices of scattering objects.

  • Coordination complexes of Mn(II), Co(II), Ni(II), Zn(II) and Cd(II) with histaminol – Crystal structures and formation constants in aqueous solution
    • Piotr Maślewski
    • Dariusz Wyrzykowski
    • Weronika Kentner
    • Anna Ciborska
    • Anna Dołęga
    2020 POLYHEDRON

    Stability constants were determined for a series of coordination complexes of Mn(II), Co(II), Ni(II), Zn(II) and Cd(II) with histaminol in aqueous solution. The tendency of histaminol to form chelate complexes has been confirmed by the isolation of several complex species in the monocrystalline form and determination of their molecular structures.

  • Copolymerization of Styrene and Pentadecylphenylmethacrylate (PDPMA): Synthesis, Characterization, Thermomechanical and Adhesion Properties
    • Tomy Muringayil
    • Sumi Murali Nair
    • Suresh Kattimuttathu Ittara
    • Józef Haponiuk
    • Sabu Thomas
    2020 Full text Polymers

    The copolymerization of styrene (St) with a bioderived monomer, pentadecylphenylmethacrylate (PDPMA), via atom transfer radical polymerization (ATRP) was studied in this work.The copolymerization reactivity ratio was calculated using the composition data obtained from1HNMR spectroscopy, applying Kelen-Tudos and Finemann-Ross methods. The reactivity ratio of styrene (r1=0.93) and PDPMA (r2=0.05) suggested random copolymerization of the two monomers with alternation. The copolymerization conversion increased with increasing PDPMA concentrationof the feed, upto 70 wt % PDPMA, but decreased thereafter. The molecular weight determined by gel permeation chromatography was lower than the theoretical values and the polydispersity increased from 1.32 to 2.19, with increasing PDPMA content in the feed. The influence of styrene content on the glass transition and thermal decomposition behavior of the copolymers was studied bydifferential scanning calorimetry (DSC) and thermogravimetric analysis, respectively. Morphologicalcharacterization by transmission electron microscopy (TEM) revealed a phase separated soft core-hardshell type structure. The complex viscosity and adhesion properties like peel strength and lap shear strength of the copolymer on different substrates increased with increasing styrene content

  • Corporate Entrepreneurship: A Literature Review and Future Research Perspectives
    • Magdalena Popowska
    2020 Full text International Journal of Contemporary Management

    Background. Nowadays, corporate entrepreneurship (CE) is perceived as an essential approach to boost the innovation and creativity within existing organizations for achieving higher opportunities in the market. This paper examines this concept, which has been largely discussed in the Anglo-Saxon world over the last thirty years. Like for many other phenomena, also in case of CE, this discussion has provided numerous conceptualizations, and consequently, there is not one unique definition of CE. In this respect, the search for an appropriate basis for understanding and describing the phenomenon of CE engenders a challenging issue for entrepreneurship researchers. Research aims. This paper aims at creating a large platform for understanding the concept of CE by means of a clarification effort through the review of the most important papers in this field and identification of the existing research gaps. Methodology. Systematic literature survey is the applied methodology. EBSCO and Taylor & Francis database were used as a source for the sampling process. Key findings. The analysis does acknowledge the need for more qualitative and rigorous research in this field and brings several recommendations for the future studies. The main conclusions also do urge for a more diversified research in terms of the sectors discussed, as the biggest gap identified is in the services sector. There is also a need for a more structured classification of the measures, depending on the real research focus: CE antecedents or outcomes.

  • Corporate social responsibility practices incomes and outcomes: Stakeholders' pressure, culture, employee commitment, corporate reputation, and brand performance. A Polish–German cross‐country study
    • Rafał Kowalczyk
    • Wioleta Kucharska
    2020 Full text Corporate Social Responsibility and Environmental Management

    This study aims to compare employee perception of corporate social responsibility (CSR) practice incomes and outcomes in the construction industry in Poland and Germany. It proposes a model that examines the influence of stakeholder pressure, culture, and CSR practices on company brand performance, reputation, and employee identification. The findings suggest that the structure of relationships varies for project‐managed construction companies in a developed country such as Germany and a rapidly transformed Poland. The structural equation modeling method was adopted to analyze the differences between the structures of relationships using AMOS and Process software. The key finding reveals that stakeholder pressure can lead to consistent CSR‐oriented system in the business environment. This study was first conducted in 2018 and then replicated in 2019 to confirm the results with 1,674 cases. The novelty essence is the comparison of the Polish and German structure of CSR practice incomes and outcomes related to employee perception.

  • Correction of determined coordinates of railway tracks in mobile satellite measurements
    • Andrzej Wilk
    • Cezary Specht
    • Krzysztof Karwowski
    • Władysław Koc
    • Jacek Skibicki
    • Krzysztof Czaplewski
    • Piotr Chrostowski
    • Paweł Dąbrowski
    • Sławomir Grulkowski
    • Sławomir Judek
    • Mariusz Specht
    • Jacek Szmagliński
    2020 Full text Diagnostyka

    This article examines one of the basic issues related to the technique of mobile satellite measurements in railway tracks. This problem concerns the correction of the determined coordinates of the track centerline. The need to perform this operation results from the GNSS receivers positioning at a certain height above the level of the existing track axis, leading to longitudinal and lateral shifts of antennas. The key problem here is the determination of the local horizontal coordinate system in each measured position. For the analysis, the authors defined the directional baseline vector of the measuring platform on the basis of positions given by two satellite antennas, positioned over the pivots of its bogies. This work presents the procedure for determining the corrections values

  • Correlation between partial inhibition of hydrogen evolution using thiourea and catalytic activity of AB5-type hydrogen storage alloy towards borohydride electrooxidation
    • Małgorzata Graś
    • Jarosław Wojciechowski
    • Katarzyna Lota
    • Tomasz Buchwald
    • Jacek Ryl
    • Grzegorz Lota
    2020 Full text JOURNAL OF ALLOYS AND COMPOUNDS

    Direct borohydride fuel cells (DBFCs) are devices which directly convert the chemical energy stored in the borohydride ion and oxidant into electrical energy as a result of redox reactions. Unfortunately, a significant amount of fuel is lost as a result of the undesirable hydrolysis reaction. The selection of an efficient borohydride hydrolysis inhibitor requires detailed knowledge regarding the interaction mechanism between the inhibitor molecule and electrode surface. In this study, various amounts of thiourea additives (0.011–1.600 mM) were tested to select the best fuel composition for DBFC application. When AB5-type anode was used, only partial inhibition of sodium borohydride hydrolysis was a desirable phenomenon. Partially released hydrogen results in the improvement of catalytic properties of the alloy. The addition of 0.016 mM thiourea does not inhibit the oxidation of borohydride, on the contrary, it increases the practical capacity from 27% to 41% of the theoretical value. Moreover, we indicate that the addition of thiourea prevents corrosion as well as degradation of the electrode surface. Pressure measurements confirmed the effectiveness of thiourea in relation to hydrogen evolution, while X-ray photoelectron spectroscopy and Raman spectroscopy revealed that the electrode surface was not poisoned.