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Gdańsk University of Technology

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  • Bringing Bathymetry LiDAR to Coastal Zone Assessment: A Case Study in the Southern Baltic
    • Paweł Tysiąc
    2020 Full text Remote Sensing

    One of the major tasks in environmental protection is monitoring the coast for negative impacts due to climate change and anthropopressure. Remote sensing techniques are often used in studies of impact assessment. Topographic and bathymetric procedures are treated as separate measurement methods, while methods that combine coastal zone analysis with underwater impacts are rarely used in geotechnical analyses. This study presents an assessment of the bathymetry airborne system used for coastal monitoring, taking into account environmental conditions and providing a comparison with other monitoring methods. The tests were carried out on a section of the Baltic Sea where, despite successful monitoring, coastal degradation continues. This technology is able to determine the threat of coastal cliff erosion (based on the geotechnical analyses). Shallow depths have been reported to be a challenge for bathymetric Light Detection and Ranging (LiDAR), due to the difficulty in separating surface, water column and bottom reflections from each other. This challenge was overcome by describing the classification method used which was the CANUPO classification method as the most suitable for the point cloud processing. This study presents an innovative approach to identifying natural hazards, by combining analyses of coastal features with underwater factors. The main goal of this manuscript is to assess the suitability of using bathymetry scanning in the Baltic Sea to determine the factors causing coastal erosion. Furthermore, a geotechnical analysis was conducted, taking into account geometrical ground change underwater. This is the first study which uses a coastal monitoring approach, combining geotechnical computations with remote sensing data. This interdisciplinary scientific research can increase the awareness of the environmental processes.

  • Buckling analysis of a non-concentric double-walled carbon nanotube
    • Mohammad Malikan
    • Victor Eremeev
    • Hamid M. Sedighi
    2020 Full text ACTA MECHANICA

    On the basis of a theoretical study, this research incorporates an eccentricity into a system of compressed double-walled carbon nanotubes (DWCNTs). In order to formulate the stability equations, a kinematic displacement with reference to the classical beam hypothesis is utilized. Furthermore, the influence of nanoscale size is taken into account with regard to the nonlocal approach of strain gradient and the van der Waals interaction for both inner and outer tubes is also considered based on the Lennard-Jones model. Galerkin decomposition technique is employed to numerically deal with the governing equations. It is evidently demonstrated that the geometrical eccentricity remarkably affects the stability threshold and its impact is to increase the static stability of DWCNTs.

  • Budownictwo morskie. Wybrane zagadnienia wraz z przykładami obliczeniowymi
    • Waldemar Magda
    2020

    Jednym z głównych zadań projektanta budowli morskiej jest poprawne uwzględnienie kombinacji oddziaływań takich czynników jak: falowanie, prądy morskie, wiatr, zjawiska sejsmiczne. Innym istotnym elementem jego pracy jest zagwarantowanie spełnienia warunków stateczności budowli poprzez umiejętną analizę współoddziaływania środowiska morskiego i budowli morskiej z jednoczesnym interaktywnym projektowaniem geometrii budowli oraz doborem właściwych parametrów materiałowych. Niniejsza publikacja dotyczy wybranych zagadnień związanych z inżynierią morską. Na przykładzie typowych budowli morskich: falochronu pionowościennego, falochronu narzutowego oraz rurociągu podmorskiego przedstawiono metody umożliwiające określenie obciążenia tych budowli – zarówno w postaci obciążenia hydrostatycznego, jak i obciążenia hydrodynamicznego. Autor krok po kroku prezentuje szczegółowe rozwiązania licznych zadań rachunkowych, w których uwzględniono typowe schematy obciążeń, możliwe do zaistnienia w warunkach rzeczywistej pracy budowli morskiej. Aby ułatwić Czytelnikowi do maksimum osiągnięcie pozytywnych wyników samokształcenia na bazie prezentowanej książki, autor daje Czytelnikowi możliwość skorzystania z darmowej wersji wykonawczej autorskiego programu komputerowego, przygotowanego specjalnie jako uzupełnienie materiału przedstawionego w książce. Książka przeznaczona jest dla pracowników biur projektów budownictwa hydrotechnicznego, osób na stanowiskach związanych z projektowaniem, wykonawstwem i nadzorem w czasie procesu inwestycyjnego, a także pracowników naukowych oraz studentów budownictwa hydrotechnicznego i inżynierii morskiej i brzegowej.

  • Bulk-Surface Modification of Nanoparticles for Developing Highly-Crosslinked Polymer Nanocomposites
    • Maryam Jouyandeh
    • Mohammad Ganjali
    • Mustafa Aghazadeh
    • Sajjad Habibzadeh
    • Krzysztof Formela
    • Mohammad Saeb
    2020 Full text Polymers

    Surface modification of nanoparticles with functional molecules has become a routine method to compensate for diffusion-controlled crosslinking of thermoset polymer composites at late stages of crosslinking, while bulk modification has not carefully been discussed. In this work, a highly-crosslinked model polymer nanocomposite based on epoxy and surface-bulk functionalized magnetic nanoparticles (MNPs) was developed. MNPs were synthesized electrochemically, and then polyethylene glycol (PEG) surface-functionalized (PEG-MNPs) and PEG-functionalized cobalt-doped (Co-PEG-MNPs) particles were developed and used in nanocomposite preparation. Various analyses including field-emission scanning electron microscopy, Fourier-transform infrared spectrophotometry (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM) were employed in characterization of surface and bulk of PEG-MNPs and Co-PEG-MNPs. Epoxy nanocomposites including the aforementioned MNPs were prepared and analyzed by nonisothermal differential scanning calorimetry (DSC) to study their curing potential in epoxy/amine system. Analyses based on Cure Index revealed that incorporation of 0.1 wt.% of Co-PEG-MNPs into epoxy led to Excellent cure at all heating rates, which uncovered the assistance of bulk modification of nanoparticles to the crosslinking of model epoxy nanocomposites. Isoconversional methods revealed higher activation energy for the completely crosslinked epoxy/Co-PEG-MNPs nanocomposite compared to the neat epoxy. The kinetic model based on isoconversional methods was verified by the experimental rate of cure reaction.

  • Burnout as a State: Random-Intercept Cross-Lagged Relationship Between Exhaustion and Disengagement in a 10-Day Study
    • Beata Basińska
    • Ewa Gruszczyńska
    2020 Full text Psychology Research and Behavior Management

    Background: Burnout has been traditionally seen as a chronic and stable state in response to prolonged stress. However, measures of momentary burnout are not well established, even though the within-person approach suggests that the symptoms of burnout may vary from day to day for the same employee. The aim of this study is to examine the daily inter- and intra-personal variability of the symptoms of burnout and the cross-lagged relationship between two components of burnout, exhaustion and disengagement. Methods: An online diary study over 10 consecutive workdays was conducted among 235 civil servants (75% women, average tenure of 15 years). Daily burnout was measured with the eight-item Oldenburg Burnout Inventory. Results: The intra-class correlation coefficients indicate that, although significant betweenperson variability exists, most of the burnout variance is within persons. Using the random intercept cross-lagged panel (RI-CLP) model to control for these between-person differences, mainly insignificant “pure” within-person cross-lagged relationships between exhaustion and disengagement were revealed. Moreover, day-to-day autoregressive effects were weaker than same-day residual correlations. Conclusion: This is one of the first studies to use daily diaries and the RI-CLP model to study burnout, including the separation of the more stable and more dynamic parts of each component. When stable parts were controlled for, the same-day relationships between exhaustion and disengagement were more pronounced than day-to-day effects. This might suggest stronger situational influences than carryover mechanism. Thus, conceptualizing burnout in terms of daily symptoms may shed promising insights into how it develops and add implications for pro-healthy changes in the workplace.

  • Burnout as a State: Random-Intercept Cross-Lagged Relationship Between Exhaustion and Disengagement in a 10-Day Study [Response to Letter]
    • Beata Basińska
    • Ewa Gruszczyńska
    2020 Psychology Research and Behavior Management

    We are writing in response to the Letter to the Editor by Block, Bair, and Carillo regarding our study, which took a multilevel approach to examine cross-lagged and co-existing relationships between exhaustion and disengagement, measured daily for ten consecutive working days using the Oldenburg Burnout Inventory (OLBI). We assessed the job burnout symptoms using only eight items, all of them worded negatively. Following Block, Bair, and Carillo’s request, we are happy to provide supplementary cross-sectional results from the first day of our study.

  • Buzz-based recognition of the honeybee colony circadian rhythm
    • Tymoteusz Cejrowski
    • Julian Szymański
    • Doina Logofătu
    2020 Full text COMPUTERS AND ELECTRONICS IN AGRICULTURE

    Honeybees are one of the highly valued pollinators. Their work as individuals is appreciated for crops pollination and honey production. It is believed that work of an entire bee colony is intense and almost continuous. The goal of the work presented in this paper is identification of bees circadian rhythm with a use of sound-based analysis. In our research as a source of information on bee colony we use their buzz that have been analysed using algorithms. For the purpose of bees day/night definition, a dedicated electronic system has been developed. The data analysis involves demonstration of the circadian rhythm based on the RMS signal level. Method for defining the start and end of the presumed bees’ night was also presented. Mel Frequency Cepstral Coefficients (MFCCs) features and SVM classifier were used. The performed experiment shown the existence of repetitive cycles, which may indicate the presence of bee night. An attempt was made to estimate the time range of this phenomenon.

  • Can high hydrostatic pressure processing be the best way to preserve human milk?
    • Edyta Malinowska-Pańczyk
    2020 Full text TRENDS IN FOOD SCIENCE & TECHNOLOGY

    Breastfeeding is one of the most important factors influencing proper child development. When a mother cannot breastfeed, the best alternative, especially for feeding premature infants, is to then use of human milk (HM) which has been collected, preserved and stored in Human Milk Banks (HMB). Scope and approach: In this review, the impact of some stages of the management of HM in HMB on its final biological value and microbiological safety are described. Negative changes in HM components begin during the first stage of frozen storage. In the next stages, further losses occur, which largely depend on the applied method of microbiota elimination. Complete inactivation of milk microbiota can be achieved after pressurization in the range 500-600 MPa, but similarly for holder pasteurization (HoP), in these conditions unfavorable changes in the milk components take place. At lower pressures, the changes are smaller, but microbiological safety of HM is not achieved. Key findings and conclusions: Replacing HoP with pressurization does not seem to be justified so far, not only because of the small differences in the retention of valuable HM ingredients, but also because of the high costs associated with the inclusion of the device for generating pressure in the HMB environment. A new solution may be the use of high-pressure milk storage at subzero temperatures, but this hypothesis must be verified.

  • Capacitance Enhancement by Incorporation of Functionalised Carbon Nanotubes into Poly(3,4-Ethylenedioxythiophene)/Graphene Oxide Composites
    • Anita Cymann
    • Mirosław Sawczak
    • Jacek Ryl
    • Ewa Klugmann-Radziemska
    • Monika Wilamowska-Zawłocka
    2020 Full text Materials

    This paper reports on the role of oxidised carbon nanotubes (oxMWCNTs) present in poly-3,4-ethylenedioxytiophene (PEDOT)/graphene oxide (GOx) composite. The final ternary composites (pEDOT/GOx/oxMWCNTs) are synthesised by an electrodeposition process from the suspension-containing monomer, oxidised carbon nanotubes and graphene oxide. Dissociated functional groups on the surface of graphene oxide play a role of counter-ions for the polymer chains. Detailed physicochemical and electrochemical characterisation of the ternary composites is presented in the paper. The results prove that the presence of oxMWCNTs in the ternary composites doubles the capacitance values compared to the binary ones (450 vs. 270 F cm3 for PEDOT/GOx/oxMWCNTs and PEDOT/GOx, respectively). The amount of carbon nanotubes in the synthesis solution is crucial for physicochemical properties of the composites, their adhesion to the electrode substrate and the electrochemical performance.

  • Carbon Dioxide Recovery Skid
    • Kamil Stasiak
    • Paweł Ziółkowski
    • Dariusz Mikielewicz
    2020 Full text Progress in Petrochemical Science

    In the face of tightening climate regulations, the adoption of carbon dioxide recovery systems is inevitable. Modular process skid units have been widely adopted across the industry. The gas-steam power plant skid unit with the carbon dioxide recovery system was described. The proposed skid module consists of the compact cycle with the oxy-combustion and the carbon dioxide capture skid unit producing pure compressed CO2. The compactness of the suggested skid can be achieved due to a novel small size designs of the wet combustion chamber and the spray-ejector condenser.

  • Carbon Nanomaterials From Metal-Organic Frameworks: A New Material Horizon for CO2 Reduction
    • Xiaoxu Xuan
    • Songying Chen
    • Shan Zhao
    • Joon Yong Yoon
    • Grzegorz Boczkaj
    • Xun Sun
    2020 Full text Frontiers in Chemistry

    The rise of CO2 in the atmosphere, which results in severe climate change and temperature increase, is known as the major reason for greenhouse effect. Reducing CO2 to value-added products is an attractive solution to this severe problem, along with addressing the energy crisis, to which the catalysts being employed are of vital importance. Due to their high porosity and tunable compositions, Metal-Organic Frameworks (MOFs) show great potentials in energy conversion systems. By thermal or chemical treatment methods, the MOFs are easily turned to MOF derived carbon nanomaterials. The much higher conductivity enables MOF derived carbon nanomaterials to be employed in CO2 conversion processes. The present review, discusses the state of the art of MOF derived carbon nanomaterials in CO2 electrochemical, photocatalytic, and thermal reduction applications. The corresponding reaction mechanisms and influence of various factors on catalyst performance are elaborated. Finally, the deficiencies and recommendations are provided for the future progress.

  • Carboxylation Enhances Fragmentation of Furan upon Resonant Electron Attachment
    • Mateusz Zawadzki
    • Thomas F. M. Luxford
    • Jaroslav Kočišek
    2020 Full text JOURNAL OF PHYSICAL CHEMISTRY A

    We report a dissociative electron attachment study to 2-furoic acid (C5H4O3) isolated in a gas phase, which is a model molecule consisting of a carboxylic group and a furan ring. Dissociation of furan by low energy electrons is accessible only via electronic excited Feshbach resonances at energies of incident electrons above 5 eV. On the other hand, carboxylic acids are well- known to dissociate via attachment of electrons at subexcitation energies. Here we elucidate how the electron and proton transfer reactions induced by carboxylation influence stability of the furan ring. Overlap of the furan and carboxyl π orbitals results in transformation of the nondissociative π2 resonance of the furan ring to a dissociative resonance. The interpretation of hydrogen transfer reactions is supported by experimental studies of 3-methyl-2-furoic and 5-methyl-2-furoic acids (C6H6O3) and density functional theory (DFT) calculations.

  • Cargo ships heat demand - operational experiment
    • Damian Bocheński
    • Dominik Kreft
    2020 Full text Polish Maritime Research

    The paper presents the results of an experiment conducted on two cargo ships – a 5300 TEU container with a steam heating system and a 7500 dwt general cargo ship with a thermal oil system. On both ships research has been carried out using specially designed measuring equipment. After gathering data about flow velocity and temperatures (steam/ cooling water/ thermal oil/ seawater/ outside air), calculations have been done, resulting in histograms. For both types of histograms (heat demand and service time), the probability density function was fitted, using the K-S statistical test. The last step was comparison of the probability distribution mean to seawater and the outside air temperatures by linear regression and the coefficient of determination. The dependencies between the mentioned temperatures and heat demand were noted.

  • Carnivorous plants used for green synthesis of silver nanoparticles with broad-spectrum antimicrobial activity
    • Rafal Banasiuk
    • Marta Krychowiak
    • Daria Swigon
    • Wojciech Tomaszewicz
    • Angelika Michalak
    • Agnieszka Chylewska
    • Magdalena Ziabka
    • Marcin Stanisław Łapiński
    • Barbara Kościelska
    • Magdalena Narajczyk
    • Aleksandra Krolicka
    • Marta Krychowiak-Maśnicka
    2020 Full text Arabian Journal of Chemistry

    In this study, we exploit the anti-oxidative potential of four carnivorous plants to produce uniform and biologically active silver nanoparticles. The use of polyvinylpyrrolidone promoted syn-thesis of quasi-spherical nanoparticles characterized by stability and high uniformity. Their activity was tested against three human pathogens and three species of plant pathogenic bacteria. The study demonstrates the influence of synthesis method (microwave irradiation or heat radiation) and plant extract composition on nanoparticle activity. The total anti-oxidative potential of the plant extract, as well as the applied method of silver ions reduction proved to be crucial for antimicrobial activity. The highest minimal bactericidal concentration (mean value = 10 m g/mL) was obtained for silver nanoparticles synthesized with the use of water extract from Dionaea muscipula tissue.

  • Carrefour
    • Luciano Segreto
    2020

    .

  • Cascading transitions toward unconventional charge density wave states in the quasi-two-dimensional monophosphate tungsten bronze P4W16O56
    • Elen Duverger-Nédellec
    • Alain Pautrat
    • Kamil Kolincio
    • Laurence Hervé
    • Olivier Pérez
    2020 Full text IUCrJ

    Single crystals of the m = 8 member of the low-dimensional monophosphate tungsten bronzes (PO2)4(WO3)2m family were grown by chemical vapour transport technique and the high crystalline quality obtained allowed a reinvestigation of the physical and structural properties. Resistivity measurements revealed three anomalies at TC1 = 258 K, TC2 = 245 K and TC3 = 140 K, never observed until now. Parallel X-ray diffraction investigations showed a specific signature associated with three structural transitions, i.e. the appearance of different sets of satellite reflections below TC1, TC2 and TC3. Several harmonics of intense satellite reflections were observed, reflecting the non-sinusoidal nature of the structural modulations and a strong electron–phonon coupling in the material. These transitions could be associated with the formation of three successive unconventional charge density wave states.

  • Cassirer E. .Filozofia form symbolicznych. Część Druga: Myślenie Mityczne.Przekład, wstęp i opracowanie Andrzej Karalus i Przemysław Parszutowicz, Kęty: Wydaw.Marek Derewiecki,2020
    • Andrzej Karalus
    • Przemysław Parszutowicz
    2020

    Tłumaczenie ksiązki: Andrzej Karalus i Przemysław Parszutowicz

  • Catalytic Mechanism of Non-Target DNA Cleavage in CRISPR-Cas9 Revealed by Ab Initio Molecular Dynamics
    • Lorenzo Casalino
    • Łukasz Nierzwicki
    • Martin Jinek
    • Giulia Palermo
    2020 Full text ACS Catalysis

    CRISPR-Cas9 is a cutting-edge genome editing technology, which uses the endonuclease Cas9 to introduce mutations at desired sites of the genome. This revolutionary tool is promising to treat a myriad of human genetic diseases. Nevertheless, the molecular basis of DNA cleavage, which is a fundamental step for genome editing, has not been established. Here, quantum–classical molecular dynamics (MD) and free energy methods are used to disclose the two-metal-dependent mechanism of phosphodiester bond cleavage in CRISPR-Cas9. Ab initio MD reveals a conformational rearrangement of the Mg2+-bound RuvC active site, which entails the relocation of H983 to act as a general base. Then, the DNA cleavage proceeds through a concerted associative pathway fundamentally assisted by the joint dynamics of the two Mg2+ ions. This clarifies previous controversial experimental evidence, which could not fully establish the catalytic role of the conserved H983 and the metal cluster conformation. The comparison with other two-metal-dependent enzymes supports the identified mechanism and suggests a common catalytic strategy for genome editing and recombination. Overall, the non-target DNA cleavage catalysis described here resolves a fundamental open question in the CRISPR-Cas9 biology and provides valuable insights for improving the catalytic efficiency and the metal-dependent function of the Cas9 enzyme, which are at the basis of the development of genome editing tools.

  • Cathodic activation of synthesized highly defective monoclinic hydroxyl‐functionalized ZrO2 nanoparticles for efficient electrochemical production of hydrogen in alkaline media
    • Nasser Mostafa
    • M. Qhtani
    • S. Alotaibi
    • Z. Zaki
    • Sarah Alharthi
    • Mateusz Cieślik
    • Adrianna Górnicka
    • Jacek Ryl
    • Rabah Boukherroub
    • Mohammed Amin
    2020 Full text INTERNATIONAL JOURNAL OF ENERGY RESEARCH

    The high electrochemical stability of Zirconia (ZrO2) at high potentials strongly suggested it as an alternative to carbon supports, which experience reduced efficiency due to some corrosion problems particularly during prolonged electrocatalysis activity. However, the use of ZrO2 was limited by its low electrical conductivity and surface area. In this work, we developed a methodology for synthesizing monoclinic ZrO2 NPs with increased surface area and improved electrical/electrocatalytic characteristics without using any carbon‐based co‐support material or any metallic nanoparticles. In this context, for the first time, highly defective hydroxyl‐functionalized ZrO2 NPs (designated here as ZT NPs) were prepared by a hydrothermal route in the presence of sodium tartrate as a mineralizer. XRD analysis demonstrated that the produced zirconia was semicrystalline microspheres, consisting of monoclinic ZrO2 NPs with high lattice defects. The addition of tartrate ions decreased the crystallite size and increased the defects and microstrain. At the same time, the alkaline hydrogen evolution reaction (HER) catalytic activity of ZrO2 NPs was significantly increased when using sodium tartrate as mineralizer; the overpotential required to obtain 10 mA cm−2 (η10) dropped down from 490 to merely 235 mV, while an exchange current density (jo) increased 12 times to 0.22 mA cm−2. The presence of structural defects (revealed by XRD) and the increased number of active surface sites contending O‐H groups (evidenced from ATR‐FTIR and XPS) as well as the enhanced electrochemical active surface area (confirmed from double‐layer capacitance measurements) were the main reasons behind the high catalytic performance. The ZrO2 NPs catalytic activity increased even further during the long‐term stability tests under severe cathodic conditions (ZT*, ZrO2 NPs obtained after the long‐term stability, has jo = 0.47 mA cm−2 and η10 = 140 mV), approaching the activity of Pt/C catalyst. This process was assisted by mineralizer removal from the catalyst (testified by XPS). Our studies revealed that ZT* are characterized by larger electroactive surface area and more structure defects compared to ZT, where surface area and microstrains resulting from surface hydroxylation open cavities in zirconia structure.

  • Cellulose Nanofibers Isolated from the Cuscuta Reflexa Plant as a Green Reinforcement of Natural Rubber
    • Midhun Dominic C.D.
    • Rani Joseph
    • P.M. Sabura Begum
    • Meera Joseph
    • Dileep Padmanabhan
    • Leonna Angela Morris
    • Athira S Kumar
    • Krzysztof Formela
    2020 Full text Polymers

    In the present work, we used the steam explosion method for the isolation of cellulose nanofiber (CNF) from Cuscuta reflexa, a parasitic plant commonly seen in Kerala and we evaluated its reinforcing efficiency in natural rubber (NR). Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Thermogravimetric analysis (TGA) techniques indicated that type I cellulose nanofibers, with diameter: 10–30 nm and a 67% crystallinity index were obtained by the proposed method. The results showed that application of CNF in NR based nanocomposites resulted in significant improvement of their processing and performance properties. It was observed that the tensile strength and tear strength of NR/CNF nanocomposites are found to be a maximum at 2 phr CNF loading, which corresponds with the studies of equilibrium swelling behavior. Dynamic mechanical analysis, thermogravimetric analysis, and morphological studies of tensile fractured samples also confirm that CNF isolated from Cuscuta reflexa plant can be considered as a promising green reinforcement for rubbers.

  • CENTRUM w systemie STRADAR – funkcje, architektura i realizacja
    • Marek Blok
    • Sylwester Kaczmarek
    • Magdalena Młynarczuk
    2020 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    System STRADAR jest rozwiązaniem umożliwiającym utworzenie infrastruktury komunikacyjno-teleinformatycznej przeznaczonej dla Morskiego Oddziału Straży Granicznej. Artykuł ten jest kolejną z cyklu publikacji opisujących architekturę i rozwiązanie systemu i dotyczy jego centralnego elementu, jakim jest CENTRUM. Przedstawiono i opisano funkcje, architekturę i realizację oprogramowania CENTRUM, które może być zainstalowane na dowolnym serwerze ze środowiskiem Linux. Oprogramowanie to przeszło pozytywnie testy akceptacyjne w ramach zrealizowanego prototypu systemu.

  • Ceramic composites for single-layer fuel cells
    • Piotr Winiarz
    • Tadeusz Miruszewski
    • Sebastian Wachowski
    • Kacper Dzierzgowski
    • Iga Szpunar
    • Krzysztof Zagórski
    • Aleksandra Mielewczyk-Gryń
    • Maria Gazda
    2020 Full text SOLID STATE SCIENCES

    Composite materials consisting of acceptor doped lanthanum orthoniobate electrolyte phase (La0.98Ca0.02NbO4) and Li2O:NiO:ZnO semiconducting phase were synthesized. The precursor powder of La0.98Ca0.02NbO4 was prepared in nanocrystalline (mechanosynthesis) and microcrystalline (solid-state synthesis) form. The composite can be applied in a single-layer fuel cell, because of the presence of two phases acting as an anode and a cathode simultaneously. X-ray diffraction data show that the materials consist of two expected phases. Scanning Electron Microscope images, with Energy Dispersive X-Ray analysis show that La0.98Ca0.02NbO4 as well as Li2O:NiO:ZnO are mixed together in the volume of the material. Open circuit voltage both for nano- and microcrystalline composite do not exceed 0.8 V. The single-layer fuel cell is degrading upon time and the voltage drop is observed. The processes of ZnO reduction and Zn diffusion and evaporation as responsible for cell degradation are discussed.

  • Certified domination
    • Magda Dettlaff
    • Magdalena Lemańska
    • Jerzy Topp
    • Radosław Ziemann
    • Paweł Żyliński
    2020 Full text AKCE International Journal of Graphs and Combinatorics

    Imagine that we are given a set D of officials and a set W of civils. For each civil x ∈ W, there must be an official v ∈ D that can serve x, and whenever any such v is serving x, there must also be another civil w ∈ W that observes v, that is, w may act as a kind of witness, to avoid any abuse from v. What is the minimum number of officials to guarantee such a service, assuming a given social network? In this paper, we introduce the concept of certified domination that models the aforementioned problem. Specifically, a dominating set D of a graph G = (VG, EG) is said to be certified if every vertex in D has either zero or at least two neighbours in VG \ D. The cardinality of a minimum certified dominating set in G is called the certified domination number of G. Herein, we present the exact values of the certified domination number for some classes of graphs as well as provide some upper bounds on this parameter for arbitrary graphs. We then characterise a wide class of graphs with equal domination and certified domination numbers and characterise graphs with large values of certified domination numbers. Next, we examine the effects on the certified domination number when the graph is modified by deleting/adding an edge or a vertex. We also provide Nordhaus–Gaddum type inequalities for the certified domination number.

  • 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

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  • 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.