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Gdańsk University of Technology

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  • Changes in conditions of acoustic wave propagation in the Gdansk deep as an effect of climate changes in the Baltic Sea region
    • Grażyna Grelowska
    • Eugeniusz Kozaczka
    2020 Full text MARINE POLLUTION BULLETIN

    The article presents the results from a research project investigating acoustic climate changes in the Gdansk Deep based on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in the scientific literature. The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea as Baltic Sea, the impact of depth is not substantial. The other two factors shape the hydroacoustic conditions. In the upper layer of seawater, the dominating factor is heat exchange at the water-atmosphere interface. The observed climate warming is reflected in the water temperature rise, which results in an increased speed of sound in the upper water layer. After years of sporadic salty inflows from the North Sea, the frequency of the phenomenon has increased since 2014. As a result, the salinity at the bottom exceeds values typical for that area.

  • Changes in the structure of Armenia’s labour resources between 1993 and 2020
    • Krystyna Gomółka
    • Karol Flisikowski
    2020 Economic Annals-XXI

    The article characterises the structure of Armenia’s labour resources in the period between1993 and 2020. It aims to assess the changes on the Armenian labour market by means of a deductive analysis of historical data and observation of changes in the structure of resources based on generally available macroeconomic data. The authors evaluate these processes against the background of demographic and economic changes, by presenting and describing statistical data. Variables such as data on the economic situation of the country (income capita, inflation rate and unemployment), demographic data (employment structure, population structure, migration) are used for the analysis. The analysis demonstrates that the COVID-19 pandemic and the Nagorno-Karabakh conflict led to an economic downturn in Armenia, with GDP per capita falling, and inflation rising. A more rapid decrease in employment could be observed in 2020, manifesting itself in a declining number of employees, selfemployed and entrepreneurs. A much more significant drop in employment was observed in urban areas than in the countryside, although the total number of agricultural workers in Armenia decreased compared to the 1990s. The governmental measures and programmes aimed at protecting jobs and businesses and mitigating the effects of the COVID-19 pandemic proved to be insufficient. In 2020, fewer citizens emigrated from Armenia as a result of the state of the emergency maintained from March to June 2020 and the closing of state borders.

  • Changes of Conformation in Albumin with Temperature by Molecular Dynamics Simulations
    • Piotr Weber
    • Piotr Bełdowski
    • Krzysztof Domino
    • Damian Ledziński
    • Adam Gadomski
    2020 Full text ENTROPY

    This work presents the analysis of the conformation of albumin in the temperature range of 300K – 312K, i.e., in the physiological range. Using molecular dynamics simulations, we calculate values of the backbone and dihedral angles for this molecule. We analyze the global dynamic properties of albumin treated as a chain. In this range of temperature, we study parameters of the molecule and the conformational entropy derived from two angles that reflect global dynamics in the conformational space. A thorough rationalization, based on the scaling theory, for the subdiffusion Flory–De Gennes type exponent of 0.4 unfolds in conjunction with picking up the most appreciable fluctuations of the corresponding statistical-test parameter. These fluctuations coincide adequately with entropy fluctuations, namely the oscillations out of thermodynamic equilibrium. Using Fisher’s test, we investigate the conformational entropy over time and suggest its oscillatory properties in the corresponding time domain. Using the Kruscal–Wallis test, we also analyze differences between the root mean square displacement of a molecule at various temperatures. Here we show that its values in the range of 306K – 309K are different than in another temperature. Using the Kullback–Leibler theory, we investigate differences between the distribution of the root mean square displacement for each temperature and time window.

  • Characterization of Defects Inside the Cable Dielectric With Partial Discharge Modeling
    • Khan Qasim
    • S. Shady Refaat
    • Haitham Abu-Rub
    • A. Hamid Toliyat
    • Marek Olesz
    • Ahmad Darwish
    2020 IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT

    The continuous monitoring of power system devices is an important step toward keeping such capital assets safe. Partial discharge (PD)-based measurement tools provide a reliable and accurate condition assessment of power system insulations. It is very common that voids or cavities exist in every solid dielectric insulation medium. In this article, different voids are modeled and analyzed using an advanced finite element (FE)-based computational algorithm. The proposed approach can be used to measure PD in cavities and voids regardless of their shape and size. The frequentative scripting approach with finite element modeling (FEM) provides the results which satisfy all PD conditions. PD behavior has been studied and analyzed through PD statistical features obtained from the simulated PD signal. A comparative study between simulated and experimental results is also performed to validate the accuracy of the proposed modeling approach. To further improve the accuracy of the model, the influence and optimization of certain free parameters required for modeling has been carried out. The article shows how PD is greatly influenced by the shape and size of voids in dielectric insulators. The research realized in this article further provides the PD statistical features and its variation with respect to void shape and size. These features are utilized for the assessment of insulation quality. The variation in PD parameters with respect to voltage level is also presented and discussed.

  • Characterization of the Functionally Graded Shear Modulus of a Half-Space
    • Vladimir Zelentsov
    • Polina Lapina
    • Boris Mitrin
    • Victor Eremeev
    2020 Full text Mathematics

    In this article, a method is proposed for determining parameters of the exponentialy varying shear modulus of a functionally graded half-space. The method is based on the analytical solution of the problem of pure shear of an elastic functionally graded half-space by a strip punch. The half-space has the depth-wise exponential variation of its shear modulus, whose parameters are to be determined. The problem is reduced to an integral equation that is then solved by asymptotic methods. The analytical relations for contact stress under the punch, displacement of the free surface outside the contact area and other characteristics of the problem are studied with respect to the shear modulus parameters. The parameters of the functionally graded half-space shear modulus are determined (a) from the coincidence of theoretical and experimental values of contact stresses under the punch and from the coincidence of forces acting on the punch, or (b) from the coincidence of theoretical and experimental values of displacement of the free surface of the half-space outside the contact and coincidence of forces acting on the punch, or (c) from other conditions. The transcendental equations for determination of the shear modulus parameters in cases (a) and (b) are given. By adjusting the parameters of the shear modulus variation, the regions of “approximate-homogeneous” state in the functionally graded half-space are developed.

  • CHARACTERIZATION STUDY ON MECHANICAL PROPERTIES OF POLYESTER COATED FABRIC
    • Andrzej Ambroziak
    2020 Full text Archives of Civil Engineering

    The scope of the paper is to determine the mechanical properties of the Precontraint 1302 polyester coated fabric under uniaxial and biaxial tensile tests. The results are compared for Precontraint 1302 fabric and other types of coated fabrics. The author applied an orthotropic model and a dense net model to reflect the polyester coated fabric performance under uniaxial and biaxial tensile tests. Material parameters are specified for both constitutive models. In order to observe the variation of immediate mechanical properties, the biaxial cyclic tests are performed for different load ratios. During uniaxial and 1:1 biaxial tensile tests it is barely observable to recognize warp or weft directions on the stress-strain curves. Load history acts strongly on the mechanical properties of the Precontraint 1302 polyester fabrics. The cyclic loads cause variation of immediate longitudinal stiffness with a comparison of values determined for unloaded coated fabrics. The paper can provide scientists, engineers, and designers an experimental and theoretical basis in the field of polyester coated fabrics.

  • Chemia, a ludzki mózg
    • Bartłomiej Cieślik
    2020 Full text

    Wiele substancji chemicznych ma udowodniony wpływ na funkcjonowanie mózgu. Część z nich, jak np. hormony, produkowane są przez sam mózg. Mogą one decydować o wielu naszych zachowaniach oraz, do pewnego stopnia, wpływać na podejmowanie decyzji. Istnieją również substancje wpływające na funkcjonowanie mózgu, które mogą być dostarczane z zewnątrz. Mogą mieć one zarówno pozytywny jak i negatywny wpływ na jego funkcjonowanie. Należy zdawać sobie sprawę, że przyjmowanie różnego rodzaju używek, stymulantów, czy nawet niektórych suplementów diety może mieć poważne konsekwencja. Świadome przyjmowanie ksenobiotyków jest zatem kluczowe w zachowaniu „higieny” naszego mózgu.

  • Chemometrics for Selection, Prediction, and Classification of Sustainable Solutions for Green Chemistry—A Review
    • Marta Bystrzanowska
    • Marek Tobiszewski
    2020 Full text Symmetry-Basel

    In this review, we present the applications of chemometric techniques for green and sustainable chemistry. The techniques, such as cluster analysis, principal component analysis, artificial neural networks, and multivariate ranking techniques, are applied for dealing with missing data, grouping or classification purposes, selection of green material, or processes. The areas of application are mainly finding sustainable solutions in terms of solvents, reagents, processes, or conditions of processes. Another important area is filling the data gaps in datasets to more fully characterize sustainable options. It is significant as many experiments are avoided, and the results are obtained with good approximation. Multivariate statistics are tools that support the application of quantitative structure–property relationships, a widely applied technique in green chemistry.

  • Chestnut-Derived Activated Carbon as a Prospective Material for Energy Storage
    • Katarzyna Januszewicz
    • Anita Cymann-Sachajdak
    • Paweł Kazimierski
    • Marek Klein
    • Justyna Łuczak
    • Monika Wilamowska-Zawłocka
    2020 Full text Materials

    In this work, we present the preparation and characterization of biomass-derived activatedcarbon (AC) in view of its application as electrode material for electrochemical capacitors. Porouscarbons are prepared by pyrolysis of chestnut seeds and subsequent activation of the obtainedbiochar. We investigate here two activation methods, namely, physical by CO2and chemical usingKOH. Morphology, structure and specific surface area (SSA) of synthesized activated carbons areinvestigated by Brunauer-Emmett-Teller (BET) technique and scanning electron microscopy (SEM).Electrochemical studies show a clear dependence between the activation method (influencing porosityand SSA of AC) and electric capacitance values as well as rate capability of investigated electrodes.It is shown that well-developed porosity and high surface area, achieved by the chemical activationprocess, result in outstanding electrochemical performance of the chestnut-derived porous carbons.

  • Child-Robot Interaction Studies During COVID-19 Pandemic
    • Pinar Uluer
    • Hatice Kose
    • Agnieszka Landowska
    • Tatjana Zorcec
    • Ben Robins
    • Duygun Erol Barkana
    2020

    The coronavirus disease (COVID-19) pandemic affected our lives deeply, just like everyone else, the children also suffered from the restrictions due to COVID-19 affecting their education and social interactions with others, being restricted from play areas and schools for a long time. Although social robots provide a promising solution to support children in their education, healthcare, and social interaction with others, the precautions due to COVID-19 also introduced new constraints in social robotics research. In this paper, we will discuss the benefits and challenges encountered in child-robot interaction due to COVID-19 based on two user studies. The first study involves children with hearing disabilities, and Pepper humanoid robot to support their audiometry tests. The second study includes the child-sized humanoid robot Kaspar and interaction games with children with autism spectrum disorder (ASD).

  • Chitin nanowhiskers from shrimp shell waste as green filler in acrylonitrile-butadiene rubber: Processing and performance properties
    • Midhun Dominic C.D.
    • Rani Joseph
    • P.m. Sabura Begum
    • Aswathy Raghunandanan
    • Nelwin T. Vackkachan
    • Dileep Padmanabhan
    • Krzysztof Formela
    2020 CARBOHYDRATE POLYMERS

    In this work, chitin nanowhiskers with high crystallinity index were obtained from shrimp shells waste using acid hydrolysis method and then comprehensively characterized. Subsequently, the impact of chitin nanowhisker content on processing and performance of acrylonitrile-butadiene rubber based nanocomposites was evaluated. The results showed that the addition of chitin nanowhiskers increased tensile strength and tear strength of nanocomposites by 116% and 54%, which was related to suitable dispersion of chitin nanowhiskers in matrix. Reinforcing effect of chitin nanowhiskers in acrylonitrile-butadiene rubber was also confirmed by Wolff activity coefficient, glass transition temperature and equilibrium swelling measurements. Moreover, it was found that higher content chitin nanowhiskers significantly improve the thermal stability of studied nanocomposites. The incorporation of chitin nanowhiskers resulted in increase of 74 °C for onset degradation temperature. This work confirmed that shrimp shell waste can be upcycled into chitin nanowhiskers - promising green filler in NBR for high-performance elastomeric applications.

  • Chloroacridine derivatives as potential anticancer agents which may act as tricarboxylic acid cycle enzyme inhibitors
    • Miroslawa Cichorek
    • Anna Ronowska
    • Krystyna Dzierzbicka
    • Monika Gensicka-Kowalewska
    • Milena Deptuła
    • Iwona Pelikant-Malecka
    2020 Full text BIOMEDICINE & PHARMACOTHERAPY

    The chloroacridines affect biological forms of melanoma in different ways. Amelanotic (Ab) melanoma (with inhibited melanogenesis and higher malignancy) was particularly sensitive to the action of the chloroacridines. The Ab melanoma cells died through apoptosis and through death without caspase activation. Diminished activity of TAC enzymes was noticed among Ab melanoma cells together with ATP/NAD depletion, especially in the case of 1b. Our data show that the biological forms of the tumors responded to 1a and its 4-methylated analog in different ways. 1a and 1b could be inducers of regulated melanoma cell death, especially the amelanotic form. Although the mechanism of the cell death is not fully understood, 1b may act by interfering with the TAC enzymes and blocking specific pathways leading to tumor growth. This could encourage further investigation of its anticancer activity, especially against the amelanotic form of melanoma.

  • Choosing Exploration Process Path in Data Mining Processes for Complex Internet Objects
    • Teresa Zawadzka
    • Wojciech Waloszek
    2020 Advances in Intelligent Systems and Computing

    We present an experimental case study of a novel and original framework for classifying aggregate objects, i.e. objects that consist of other objects. The features of the aggregated objects are converted into the features of aggregate ones, by use of aggregate functions. The choice of the functions, along with the specific method of classification can be automated by choosing of one of several process paths, and different paths can be picked for different parts of the domain. The results are encouraging and show that our approach allowing for automated choice, can be beneficial for the data mining results.

  • Choosing Exploration Process Path in Data Mining Processes for Complex Internet Objects
    • Teresa Zawadzka
    • Wojciech Waloszek
    2020

    We present an experimental case study of a novel and original framework for classifying aggregate objects, i.e. objects that consist of other objects. The features of the aggregated objects are converted into the features of aggregate ones, by use of aggregate functions. The choice of the functions, along with the specific method of classification can be automated by choosing of one of several process paths, and different paths can be picked for different parts of the domain. The results are encouraging and show that our approach allowing for automated choice, can be beneficial for the data mining results.

  • Chór wirtualny
    • Mariusz Mróz
    • Bartłomiej Mróz
    2020

    Wiosna roku 2020 została zapisana emocjami, które należy zaliczać do tych niepożądanych. Praca on-line stała się jedyną możliwą formą pracy z zespołem. Prekursorem pomysłu wirtualnego chóru był amerykański kompozytor i dyrygent Eric Whitacre. Eric wybrał do wykonania przez chór wirtualny utwory posiadające wspólne cechy. Kolejnym poruszanym zagadnieniem jest stworzenie przestrzennego dźwięku. Technologia na której opiera się dźwięk przestrzenny nazywana jest ambisonią. Niewątpliwe walory chórów wirtualnych, i ich możliwości twórcze są wartością kultury XXI wieku. Koncert w realnym świecie jest żywy, kreuje dzieło muzyczne jedynie „tu i teraz”. Ubarwia emocjami wszystkich uczestników koncertu w danym miejscu i czasie. Wirtualna rzeczywistość może być piękna, jednak przeżywanie czegoś wyjątkowego zawsze wiąże się z koniecznością przebywania w centrum wydarzeń.

  • Chromatic cost coloring of weighted bipartite graphs
    • Tytus Pikies
    • Marek Kubale
    2020 APPLIED MATHEMATICS AND COMPUTATION

    Given a graph G and a sequence of color costs C, the Cost Coloring optimization problem consists in finding a coloring of G with the smallest total cost with respect to C. We present an analysis of this problem with respect to weighted bipartite graphs. We specify for which finite sequences of color costs the problem is NP-hard and we present an exact polynomial algorithm for the other finite sequences. These results are then extended to a substantial class of infinite sequences. We show that these results on both types of sequences partially transfer to unweighted bipartite graphs.

  • Ciprofloxacin-modified degradable hybrid polyurethane-polylactide porous scaffolds developed for potential use as an antibacterial scaffold for regeneration of skin
    • Iga Carayon
    • Agata Terebieniec
    • Marcin Łapiński
    • Natalia Filipowicz
    • Justyna Kucińska-Lipka
    2020 Full text Polymers

    The aim of the performed study was to fabricate an antibacterial and degradable scaffold that may be used in the field of skin regeneration. To reach the degradation criterion for the biocompatible polyurethane (PUR), obtained by using amorphous α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA), was used and processed with so-called “fast-degradable” polymer polylactide (PLA) (5 or 10 wt %). To meet the antibacterial requirement obtained, hybrid PUR-PLA scaffolds (HPPS) were modified with ciprofloxacin (Cipro) (2 or 5 wt %) and the fluoroquinolone antibiotic inhibiting growth of bacteria, such as Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, which are the main causes of wound infections. Performed studies showed that Cipro-modified HPPS, obtained by using 5% of PLA, possess suitable mechanical characteristics, morphology, degradation rates, and demanded antimicrobial properties to be further developed as potential scaffolds for skin tissue engineering.

  • Circular polarization diversity implementation for correlation reduction in wideband low-cost multiple-input-multiple-output antenna
    • Ubaid Ullah
    • Muath Al-hasan
    • Sławomir Kozieł
    • Ismail Mabrouk
    2020 Full text IEEE Access

    In this paper, a multiple-input-multiple-output (MIMO) antenna featuring circular polarization diversity, and designed on a common coplanar ground is presented. The proposed antenna design utilizes a coplanar waveguide (CPW) feeding technique with three parallel coplanar ground planes, and two feedlines in-between. For circular polarization (CP), quasi-loops are created by etching slots on the outermost ground planes. With this configuration, circular polarization diversity is induced in the MIMO antenna with the left-hand CP (LHCP) from one antenna and the right-hand CP (RHCP) from the other. The total footprint of the antenna radiator is only 0.78λ0 × 0.55λ0 = 0.42λ02. Experimental results show perfectly overlapping impedance and axial ratio bandwidths of 39.3% (4.5 GHz to 6.7 GHz). In addition, average in-band isolation |S21| ≤ –15 dB without any added complexity or active circuit elements. The peak realized gain of the antenna is 5.8 dBic with broadside radiation pattern in the +z- direction and envelope correlation coefficient (ECC) of 0.005. The antenna is suitable for multiple applications in the C-band that includes WLAN (5 GHz, 5.2 GHz and 5.8 GHz) and WiMAX (5.5 GHz).

  • Civil liability for artificial intelligence products versus the sustainable development of CEECs: which institutions matter?
    • Małgorzata Godlewska
    • Sylwia Morawska
    • Przemysław Banasik
    2020 Full text Ruch Prawniczy, Ekonomiczny i Socjologiczny

    The aim of this paper is to conduct a meta-analysis of the EU and CEECs civil liability institutions in order to find out if they are ready for the Artificial Intelligence (AI) race. Particular focus is placed on ascertaining whether civil liability institutions such as the Product Liability Directive (EU) or civil codes (CEECs) will protect consumers and entrepreneurs, as well as ensure undistorted competition. In line with the aforementioned, the authors investigate whether the civil liability institutions of the EU and CEECs are based on regulations that can be adapted to the new generation of robots that will be equipped with learning abilities and have a certain degree of unpredictability in their behaviour. The conclusion presented in the paper was drawn on the basis of a review of the current literature and research on national and European regulations. The primary contribution that this article makes is to advance the current of the research concerning the concepts of AI liability for damage and personal injury. A second contribution is to show that the current civil liability institutions of the EU as well as the CEECs are not sufficiently prepared to address the legal issues that will start to arise when self-driving vehicles or autonomous drones begin operating in fully autonomous modes and possibly cause property damage or personal injury.

  • Coin
    • Luciano Segreto
    2020

    .

  • Collaborative Data Acquisition and Learning Support
    • Tomasz Boiński
    • Julian Szymański
    2020 Full text International Journal of Computer Information Systems and Industrial Management Applications

    With the constant development of neural networks, traditional algorithms relying on data structures lose their significance as more and more solutions are using AI rather than traditional algorithms. This in turn requires a lot of correctly annotated and informative data samples. In this paper, we propose a crowdsourcing based approach for data acquisition and tagging with support for Active Learning where the system acts as an oracle and repository of training samples. The paper presents the CenHive system implementing the proposed approach. Three different usage scenarios are presented that were used to verify the proposed approach.

  • COLLABORATIVE LEARNING ENVIRONMENT FOR ENGINEERING EDUCATION (COLED)
    • Anna Grabowska
    • Anna Czaja
    • Ewa Kozłowska
    • Jacek Zieliński
    2020

    Collaborative Learning Environment for Engineering Education is a European project implemented under the Erasmus + program, The main goal of 5 partners from 4 different European countries – Bulgaria, Poland, Portugal and Romania is to develop an innovative collaborative training approach, encompassing curricula related to the introduction of enterprise automation. Project activities are carried out in the period from Dctober 2018 to December 2020.

  • Collision-induced luminescence spectra of pyridine bombarded by 1000 eV He+ cations
    • Tomasz Wąsowicz
    2020 Full text Results in Physics

    Here we show collision-induced luminescence spectra measured for collisions of the He+cations with thearomatic six-membered ring of the pyridine molecule (C5H5N). Distinct emission bands due to the CH(A2Δ→X2Πr;B2Σ+→X2Πr;C2Σ+→X2Πr), CN(B2Σ+→X2Σ+), C2(d3Πg→a3Πu), and NH(A3Π→X3Σ−) transitions, aswell as atomic H, He, and C lines have been observed. Apart from the He atoms, all the emitters arise from thefragmentation of the pyridine ring. The identification of the helium lines indicates a single electron transferreaction from the pyridine molecule to the He+cations. The products’intensities relative to the Hβintensityhave also been obtained and compared with the intensity ratios determined for He++ furan collisions.

  • Colloidal transport of lipid digesta in human and porcine small intestinal mucus
    • Adam Macierzanka
    • Olivia Ménard
    • Didier Dupont
    • Krzysztof Gutkowski
    • Robert Staroń
    • Lukasz Krupa
    2020 Full text FOOD RESEARCH INTERNATIONAL

    Small intestinal mucus transport of food-derived particulates has not been extensively studied, despite mucus being a barrier nutrients need to cross before absorption. We used complex dispersions of digesta obtained from simulated, dynamic gastrointestinal digestion of yogurt to examine the penetrability of human and porcine mucus to the particles formed of lipolysis products. Quantitative, time-lapse confocal microscopy revealed a sieve-like behaviour of the pig jejunal and ileal mucus. The digesta diffusivity decreased significantly over the first 30 min of mucus penetration, and then remained constant at ca. 5×10-12 m2s-1 (approx. 70% decrease from initial values). A non-significantly different penetrability was recorded for the ileal mucus of adult humans. The digesta diffusion rates in neonatal, jejunal mucus of 2 week old piglets were 5–8 times higher than in the three different types of adult mucus. This is the first report that validates the mucus of fully-grown pigs as a human-relevant substitute for mucus permeation studies of nutrients/bio-actives and/or complex colloidal dispersions (e.g., post-digestion food particulates, orally-administrated delivery systems).

  • Column base fixity in steel moment frames: Observations from instrumented buildings
    • Tomasz Falborski
    • Ahmad Hassan
    • Amit Kanvinde
    2020 JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH

    The rotational fixity of column base connections in Steel Moment Resisting Frames (SMRFs) strongly influences their seismic response. However, approaches for estimating base fixity have been validated only against laboratory test data. These approaches are examined based on strong motion recordings from four instrumented SMRF buildings in California to informbest practices for seismic response simulation. These buildings represent a range of structural properties, including height, layout, as well as different types of base connections and foundations. Three-dimensional simulationmodels are constructed for these buildings, including the gravity framing and nonstructural stiffness. For each building, base fixities are parametrically varied. These include pinned and fixed bases, aswell as intermediate fixities determined frompreviously developedmodels that are appropriate for simulating the specific types of base connections used in the buildings. The simulated response of these buildings is comparedwith strong motion recordings to informoptimal approaches for simulating column bases. The results indicate that: (1) for frames with exposed base plate connections, model-based estimates of base fixity result in the least error with respect to the recordings, compared to both pinned and fixed estimates, (2) for frames with embedded base connections, model-based estimates, as well as the fixed base assumption are equivalent, resulting in the least error, whereas the pinned base estimate results in large error, and (3) if simulated with the appropriate estimate of fixity as inferred fromthese observations, the simulations predict peak displacements and accelerations with good accuracy.

  • Combination of instrumental and qualitative descriptive analysis for evaluation of selected tonic waters quality features
    • Ewa Marjańska
    • Maria Szpakowska
    2020 JOURNAL OF TEXTURE STUDIES

    The combination of sensory and instrumental analysis was applied for quality assurance of selected tonic waters. The Quantitative Descriptive Analysis (QDA) in terms of fourteen sensory attributes (aroma, astringency, bite, burn, numbing, tongue heaviness, carbonation, mouth coating, sweet taste, sour taste, bitter taste, sweet aftertaste, sour aftertaste, bitter aftertaste) of selected tonic waters was performed by sensory experts. The results of this analysis were bound with potentiometric sensor results to elaborate mathematical models for prediction of these attributes by Partial Least Squares (PLS) analysis. Predicted values of sensory attributes were in a good agreement with those obtained by sensory experts since the standard deviation on predicted values were relatively low and determination coefficients were high. The only exception was for sweet aftertaste attribute, which model was not so well-fitted, probably due to specific interactions of tonic waters’ sweet components. This approach may ensure the standards of food quality regarding sensory parameters with diminishing assessment’s time and costs. Practical application Elaborated models based on instrumental analysis with potentiometric sensor for prediction of sensory attributes (aroma, astringency, bite, burn, numbing, tongue heaviness, carbonation, mouth coating, sweet taste, sour taste, bitter taste, sweet aftertaste, sour aftertaste, bitter aftertaste) for a group of similar tonic waters ensure the highest standards of food quality assessment in terms of consumers’ sensory preferences. These models might even diminish the role of uncomfortable and expensive, sensory analysis. Elaborated models can be successfully used for quality assessment of given tonic waters before entering the sales network. This new approach to quality assessment can be applied also for other groups of similar beverages.

  • Combined Long-Period Fiber Grating and Microcavity In-Line Mach–Zehnder Interferometer for Refractive Index Measurements with Limited Cross-Sensitivity
    • Monika Janik
    • Marcin Koba
    • Krystian Król
    • Predrag Mikulic
    • Wojtek J. Bock
    • Mateusz Śmietana
    2020 Full text SENSORS

    This work discusses sensing properties of a long-period grating (LPG) and microcavity in-line Mach–Zehnder interferometer (µIMZI) when both are induced in the same single-mode optical fiber. LPGs were either etched or nanocoated with aluminum oxide (Al2O3) to increase its refractive index (RI) sensitivity up to ≈2000 and 9000 nm/RIU, respectively. The µIMZI was machined using a femtosecond laser as a cylindrical cavity (d = 60 µm) in the center of the LPG. In transmission measurements for various RI in the cavity and around the LPG we observed two effects coming from the two independently working sensors. This dual operation had no significant impact on either of the devices in terms of their functional properties, especially in a lower RI range. Moreover, due to the properties of combined sensors two major effects can be distinguished—sensitivity to the RI of the volume and sensitivity to the RI at the surface. Considering also the negligible temperature sensitivity of the µIMZI, it makes the combination of LPG and µIMZI sensors a promising approach to limit cross-sensitivity or tackle simultaneous measurements of multiple effects with high efficiency and reliability.

  • 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.