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Politechniki Gdańskiej

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  • Effective Gap Size Index for Determination of Optimum Separation Distance Preventing Pounding between Buildings during Earthquakes
    • Seyed Mohammad Khatami
    • Hosein Naderpour
    • Alireza Mortezaei
    • Seyed Mohammad Nazem Razavi
    • Natalia Lasowicz
    • Robert Jankowski
    2021 Pełny tekst Applied Sciences-Basel

    Seismic excitations may lead to collisions between adjacent civil engineering structures causing major damage. In this paper, an effective equation for calculating the gap size index is proposed so as to provide the optimum separation distance preventing structural pounding during different earthquakes. Evaluation of the best prediction of the required separation distance between two adjacent buildings was carried out by using the lumped mass multi-degree-of-freedom models of structures. Special computer program was used to perform dynamic analyses in order to confirm the accuracy of the proposed formula. For this purpose, several different models of buildings with various properties under different earthquake excitations were analyzed. The results of the study clearly show that the proposed formula for the gap size index (based on vibration periods and damping ratios of buildings) is effective and it allows us to calculate the optimum separation between adjacent structures preventing their pounding during different earthquakes.

  • Effects of Basalt and Carbon Fillers on Fire Hazard, Thermal, and Mechanical Properties of EPDM Rubber Composites
    • Przemysław Rybiński
    • Bartłomiej Syrek
    • Anna Marzec
    • Bolesław Szadkowski
    • Małgorzata Kuśmierek
    • Olusegun D. Samuel
    • Milad Amiri
    • Ulugbek Zakirovich Mirkhodjaev
    2021 Pełny tekst Materials

    Due to growing restrictions on the use of halogenated flame retardant compounds, there is great research interest in the development of fillers that do not emit toxic compounds during thermal decomposition. Polymeric composite materials with reduced flammability are increasingly in demand. Here, we demonstrate that unmodified graphene and carbon nanotubes as well as basalt fibers or flakes can act as effective flame retardants in polymer composites. We also investigate the effects of mixtures of these carbon and mineral fillers on the thermal, mechanical, and rheological properties of EPDM rubber composites. The thermal properties of the EPDM vulcanizates were analyzed using the thermogravimetric method. Flammability was determined by pyrolysis combustion flow calorimetry (PCFC) and cone calorimetry.

  • Effects of biotransport and hydro-meteorological conditions on transport of trace elements in the Scott River (Bellsund, Spitsbergen)
    • Sara Lehmann-konera
    • Waldemar Kociuba
    • Stanisław Chmiel
    • Łukasz Franczak
    • Żaneta Polkowska
    2021 Pełny tekst PeerJ

    The shaping of surface water chemistry in the Svalbard Archipelago is strongly dependent on the geology of the catchment and the process of long-range transport of atmospheric pollutants (LRATP). It was found that the dissolved trace elements in the Scott River, which catchment is characterized by a decreasing degree of glaciation, were of the natural origin (i.a. weathering and dissolution of local geological substratum). The exception was Zn originated from LRATP. The paper describe the influence changes in hydro-meteorological conditions and the presence of a seabird colony on the variability in the transport of trace elements within the Scott River catchment. The work assesses long-time fluctuations in the concentration of twenty five trace elements (i.a. Al, Cr, Cu, Pb, Sr, and Zn) from eighty-four surface water samples and their relation to changes in water discharge (Q), precipitation (P), pH, and dissolved organic carbon (DOC) at two river sites (with one being under the influence of the biotransport factor). Based on the results of matrix correlation and cluster analysis it was found that the additional load of DOC from the nesting site of Larus Argentatus in the mouth section of the river drastically changed the hydro-geochemical cycle of Co, Ni, Zn, Ga, Sr, Rb, Ba and U (0.30 < r < 0.51). Furthermore, the results of cluster analysis confirmed that the bird colony’s nesting site was strongly responsible for the presence of U, Rb, Zn, Ni and marine-derived nutrients (e.g. Se and Li). The discharge of glacier meltwater and the alkaline character of water have a negative effect on the dissolution of Li and Mn (−0.31 < r < −0.51), but positively affect the level of Rb and U (r = 0.31 and 0.35, respectively) due to it being washing out a seabird nesting colony in the mouth section of the Scott River. It was observed that the event of rises in air temperature and rain, which results in increased water discharge, caused an intense transport of the trace elements load. Moreover, results of the precipitation sensitivity coefficient factor (CF) proved that precipitation effect the occurrence of Li, Sr and U in the Scott River.

  • Effects of FSW Tool Plunge Depth on Properties of an Al-Mg-Si Alloy T-Joint: Thermomechanical Modeling and Experimental Evaluation
    • Shabbir Memon
    • Dariusz Fydrych
    • Aintzane Conde Fernandez
    • Hamed Aghajani Derazkola
    • Hesamoddin Aghajani Derazkola
    2021 Pełny tekst Materials

    One of the main challenging issues in friction stir welding (FSW) of stiffened structures is maximizing skin and flange mixing. Among the various parameters in FSW that can affect the quality of mixing between skin and flange is tool plunge depth (TPD). In this research, the effects of TPD during FSW of an Al-Mg-Si alloy T-joint are investigated. The computational fluid dynamics (CFD) method can help understand TPD effects on FSW of the T-joint structure. For this reason, the CFD method is employed in the simulation of heat generation, heat distribution, material flow, and defect formation during welding processes at various TPD. CFD is a powerful method that can simulate phenomena during the mixing of flange and skin that are hard to assess experimentally. For the evaluation of FSW joints, macrostructure visualization is carried out. Simulation results showed that at higher TPD, more frictional heat is generated and causes the formation of a bigger stir zone. The temperature distribution is antisymmetric to the welding line, and the concentration of heat on the advancing side (AS) is more than the retreating side (RS). Simulation results from viscosity changes and material velocity study on the stir zone indicated that the possibility of the formation of a tunnel defect on the skin–flange interface at the RS is very high. Material flow and defect formation are very sensitive to TPD. Low TPD creates internal defects with incomplete mixing of skin and flange, and high TPD forms surface flash. Higher TPD increases frictional heat and axial force that diminish the mixing of skin and flange in this joint. The optimum TPD was selected due to the best materials flow and final mechanical properties of joints.

  • Effects of laser pulse duration in two-photon vision threshold measurements
    • Marcin Marzejon
    • Maciej Wojtkowski
    • Łukasz Kornaszewski
    • Katarzyna Komar
    2021 Proceedings of SPIE

    Pulsed near-infrared (NIR) light sources can be successfully applied for both imaging and functional testing of the human eye, as published recently1. These two groups of applications have different requirements. For imaging applications, the most preferable is invisible scanning beam while efficiently visible stimulating beam is preferable for functional testing applications. The functional testing of human eye using NIR laser beams is possible due to two-photon vision (2PV) phenomenon. 2PV enables perception of pulsed near-infrared laser light as color corresponding to approximately half of the laser wavelength2. This study aims to characterize two-photon vision thresholds for various pulse lengths from a solid- state sub-picosecond laser (λc = 1043.3 nm, Frep = 62.65 MHz), either of 253 fs duration or elongated by Martinez- type stretcher to 2 ps, and fiber-optic picosecond laser (λc = 1028.4 nm, Frep = 19.19 MHz, p = 12.2 ps).

  • Effects of Surface Pretreatment of Titanium Substrates on Properties of Electrophoretically Deposited Biopolymer Chitosan/Eudragit E 100 Coatings
    • Łukasz Pawłowski
    • Michał Bartmański
    • Aleksandra Mielewczyk-Gryń
    • Andrzej Zieliński
    2021 Pełny tekst Coatings

    The preparation of the metal surface before coating application is fundamental in determining the properties of the coatings, particularly the roughness, adhesion, and corrosion resistance. In this work, chitosan/Eudragit E 100 (chit/EE100) were fabricated by electrophoretic deposition (EPD) and both their microstructure and properties were investigated. The present research is aimed at characterizing the effects of the surface pretreatment of titanium substrate, applied deposition voltage, and time on physical, mechanical, and electrochemical properties of coatings. The coating’s microstructure, topography, thickness, wettability, adhesion, and corrosion behavior were examined. The applied process parameters influenced the morphology of the coatings, which affected their properties. Coatings with the best properties, i.e., uniformity, proper thickness and roughness, hydrophilicity, highest adhesion to the substrate, and corrosion resistance, were obtained after deposition of chit/EE100 coating on nanotubular oxide layers produced by previous electrochemical oxidation.

  • Efficacious Alkaline Copper Corrosion Inhibition by a Mixed Ligand Copper(II) Complex of 2,2′-Bipyridine and Glycine: Electrochemical and Theoretical Studies
    • Mohamed Ibrahim
    • Dalia Saleh
    • Morad El-Hendawy
    • Ahmed Fallatah
    • Gaber Mersal
    • Rabah Boukherroub
    • Joanna Wysocka
    • Jacek Ryl
    • Mohammed Amin
    2021 ChemElectroChem

    A mixed ligand copper(II) complex, namely, [Cu(BPy)(Gly)Cl]⋅2H2O (CuC) (BPy=2,2′-bipyridine and Gly=glycine), was synthesized and characterized. The synthesized CuC complex was tested as inhibitor to effectively mitigate the corrosion of copper in alkaline solutions using the linear sweep voltammetry (LSV) and linear polarization resistance (LPR) techniques. For the sake of comparison, such two D.C. electrochemical techniques were also applied to the Cu/OH− interface in the presence of the two studied free ligands, namely, BPy and Gly. The results showed that the three studied compounds acted as mixed-type inhibitors, with CuC being the most efficacious one. The adsorption of the inhibitor is confirmed from X-ray photoelectron spectroscopy (XPS) profiles by the appearance of organic chlorine as well as pyridine and amine nitrogen bonds. Based on XPS data, it was presumed that the corrosion inhibitor stimulates the formation of Cu2CO3(OH)2 species at the electrode surface since, in the case of a corroded reference sample (in absence of inhibitors), its proportion is trivial. The reactivity of the isolated inhibitors was analyzed by computing several quantum chemical parameters based on the density functional theory (DFT). A good correlation was found between these parameters and the anticorrosive performance. Additionally, Monte Carlo simulation studies were applied to find the best configurational space of ligands and their complex on the Cu(111) surface.

  • Efficiency limit of excitonic photovoltaic cells under phosphor-based white LED illumination
    • Grażyna Jarosz
    • Małgorzata Franz
    • Rafał Marczyński
    • Ryszard Signerski
    2021 Pełny tekst ORGANIC ELECTRONICS

    The limit of energy conversion of excitonic photovoltaic cells working under white light illumination generated by phosphor-based LED is analysed using the modified Giebink approach. Particularly, the impact of the optical energy gap and energy loss associated with the excitons dissociation at the heterojunction interface on power conversion efficiency of the device are discussed. From the results of our study it follows that the optimal optical energy gap value of organic materials equals 1.87–1.91 eV for the cool light and 1.80–1.82 eV for the warm light. The value of maximum power efficiency reaches 50%, if the energy loss related to excitons dissociation at the interface ED/EA is smaller than 0.3 eV and it decreases up to 40%, if the energy loss reaches the value of 0.5 eV. The obtained results reveal the direction of further improvement of efficiency of organic photovoltaic solar cells for indoor applications.

  • EFFICIENT LINE DETECTION METHOD BASED ON 2D CONVOLUTION FILTER
    • Paweł Kowalski
    • Piotr Tojza
    2021 Pełny tekst Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

    The article proposes an efficient line detection method using a 2D convolution filter. The proposed method was compared with the Hough transform, the most popular method of straight lines detection. The developed method is suitable for local detection of straight lines with a slope from -45˚ to 45˚. Also, it can be used for curve detection which shape is approximated with the short straight sections. The new method is characterized by a constant computational cost regardless of the number of set pixels. The convolution is performed using the logical conjunction and sum operations. Moreover, design of the developed filter and the method of filtration allows for parallelization. Due to constant computation cost, the new method is suitable for implementation in the hardware structure of real-time image processing systems.

  • Efficient Surrogate Modeling and Design Optimization of Compact Integrated On-Chip Inductors Based on Multi-Fidelity EM Simulation Models
    • Piotr Kurgan
    2021 Pełny tekst Micromachines

    High-performance and small-size on-chip inductors play a critical role in contemporary radio-frequency integrated circuits. This work presents a reliable surrogate modeling technique combining low-fidelity EM simulation models, response surface approximations based on kriging interpolation, and space mapping technology. The reported method is useful for the development of broadband and highly accurate data-driven models of integrated inductors within a practical timeframe, especially in terms of the computational expense of training data acquisition. Application of the constructed surrogate model for rapid design optimization of a compact on-chip inductor is demonstrated. The optimized EM-validated design solution can be reached at a low computational cost, which is a considerable improvement over existing approaches. In addition, this work provides a description and illustrates the usefulness of a multi-fidelity design optimization method incorporating EM computational models of graduated complexity and local polynomial approximations managed by an output space mapping optimization framework. As shown by the application example, the final design solution is obtained at the cost of a few high-fidelity EM simulations of a small-size integrated coil. A supplementary description of variable-fidelity EM computational models and a trade-off between model accuracy and its processing time complements the work.

  • eFRADIR: An Enhanced FRAmework for DIsaster Resilience
    • Alija Pasic
    • Rita Girao-Silva
    • Ferenc Mogyorosi
    • Balazs Vass
    • Teresa Gomes
    • Peter Babarczi
    • Peter Revisnyei
    • Janos Tapolcai
    • Jacek Rak
    2021 Pełny tekst IEEE Access

    This paper focuses on how to increase the availability of a backbone network with minimal cost. In particular, the new framework focuses on resilience against natural disasters and is an evolution of the FRADIR/FRADIR-II framework. It targets three different directions, namely: network planning, failure modeling, and survivable routing. The steady state network planning is tackled by upgrading a sub-network (a set of links termed the spine) to achieve the targeted availability threshold. A new two-stage approach is proposed: a heuristic algorithm combined with a mixed-integer linear problem to optimize the availability upgrade cost. To tackle the disaster-resilient network planning problem, a new integer linear program is presented for the optimal link intensity tolerance upgrades together with an efficient heuristic scheme to reduce the running time. Failure modeling is improved by considering more realistic disasters. In particular, we focus on earthquakes using the historical data of the epicenters and the moment magnitudes. The joint failure probabilities of the multi-link failures are estimated, and the set of shared risk link groups is defined. The survivable routing aims to improve the network’s connectivity during these shared risk link group failures. Here, a generalized dedicated protection algorithm is used to protect against all the listed failures. Finally, the experimental results demonstrate the benefits of the refined eFRADIR framework in the event of disasters by guaranteeing low disconnection probabilities even during large-scale natural disasters.

  • Ekspertyza dot. analizy osadów z powierzchni wewnętrznej rurociągu na ssaniu pompy instalacji opóźnionego koksowania
    • Łukasz Gaweł
    • Kazimierz Darowicki
    2021

    Zakres ekspertyzy obejmuje analizę osadu na wewnętrznej stronie rurociągu prowadzącego do pompy wysokociśnieniowej 0960-P35, w tym:  Analizę chemiczną osadów z powierzchni wewnętrznej rurociągu wykonanego ze stali niestopowej  Określenie właściwości magnetycznych osadów  Wskazanie mechanizmu tworzenia się osadów  Wskazanie możliwych metod ograniczających ilość tworzących się osadów na powierzchni stali niestopowej omawianego rurociągu

  • Ekspertyza dotycząca przyczyn pęknięcia rurociągu 8”-096-P1059, zamówienie nr WU/0402/2020/MS
    • Kazimierz Darowicki
    • Stefan Krakowiak
    • Artur Zieliński
    • Mateusz Cieślik
    • Tadeusz Sonneck
    2021

    Wykonano badania nieniszczące i niszczących próbek materiału rurociągu wraz z przygotowaniem próbek do badań z materiału rodzimego.

  • Ekspertyza z oceną przyczyn powstania korozji oraz oceną ryzyka obniżenia trwałości kabli sprężenia zewnętrznego konstrukcji nośnej mostu M-4 w ciągu drogi krajowej nr 90 przez rzekę Wisłę koło Kwidzyna
    • Kazimierz Darowicki
    • Stefan Krakowiak
    • Łukasz Gaweł
    • Michał Szociński
    • Tadeusz Sonneck
    2021

    Celem pracy jest uzyskanie informacji pomocnych do podjęcia właściwej decyzji z punktu widzenia Zarządcy obiektu, co do określenia zakresu niezbędnych działań naprawczych na moście M-4 w ciągu drogi krajowej nr 90 przez rzekę Wisłę koło Kwidzyna, spowodowanych wystąpieniem korozji splotów kabli sprężenia zewnętrznego zlokalizowanego wewnątrz dźwigara skrzynkowego ustroju nośnego przedmiotowego mostu.

  • El empleo en el marco de la transformación digital: Gig Economy vs Open Collaboration ¿dos caras de una misma moneda?
    • David Duenas Cid
    2021

    Tal y como plantea Pérez [43, 44], estamos viviendo los efectos de una revolución tecnológica ligada al desarrollo de las TICs. Los procesos de innovación, describe, se retroalimentan colectivamente, involucrando diferentes actores (productores, proveedores, distribuidores y consumidores) entrelazados en clústeres o redes dinámicas y complejas. Estos procesos colectivos ayudan a desarrollar e implementar tecnologías y magnifican su impacto hasta crear nuevos paradigmas de producción y consumo. En concreto, Pérez defiende que vivimos bajo un paradigma tecno-económico como resultado de un proceso de aprendizaje colectivo que facilita el uso y la asimilación de la tecnología y su impacto en el funcionamiento de la economía. Este proceso incluye también instituciones públicas, quienes, por ejemplo, adaptan progresivamente sus sistemas

  • Electrical Tree Growth Behavior Under AC and DC High Voltage in Power Cables
    • Mohammad AlShaikh Saleh
    • Shady S. Refaat
    • Marek Olesz
    • Haitham Abu-Rub
    2021

    This work investigates the impact of an applied AC and DC high voltage on the electrical tree behavior in extruded cross-linked polyethylene (XLPE) insulation based on simulation and experimental validation. Extensive partial discharge (PD) testing methods are being implemented for high voltage cables under AC voltage for monitoring their condition. However, these PD testing methods cannot be utilized for power cables under DC voltages. DC voltages is considered in this study because of the rising implementation of HVDC cables worldwide. Therefore, it is of paramount importance to study the PD behavior originating from defects under DC voltages. Hence, classifying and diagnosing the defects taking place becomes crucial. In this paper, a 3D finite element analysis (FEA)-based modeling is considered to study the electrical treeing behavior using an embedded needle electrode in the XLPE insulation. The experiment entails PD tests with different applied high DC voltages (2.5, 5, 10, 11, and 12 kV) to study the impact on the initiation of PDs and ultimately tree growth. PD measurements were also investigated under AC voltages (7.1, 9.9, 11.3, 12.7, 14.1, and 17 kV) to compare them with PD results obtained with the applied DC voltage. The time-resolved partial discharge (TRPD) patterns are acquired for classifying the severity of the defect present in the XLPE insulation.

  • Electrochemical Evaluation of Sustainable Corrosion Inhibitors via Dynamic Electrochemical Impedance Spectroscopy
    • Paweł Ślepski
    • Husnu Gerengi
    • Gökhan Gece
    • Ertugrul Kaya
    • Marziya Rizvi
    • Michał Szociński
    2021

    Finding suitable measurement methods for the effective management of electrochemical problems is of paramount importance, particularly for improving efficiency in corrosion protection. The need for accurate measurement techniques specific to nonstationary conditions has long been recognized, and promising approaches have emerged. This chapter introduces dynamic electrochemical impedance spectroscopy as a novel advancement in electrochemistry that can be used efficiently in galvanostatic and potentiostatic modes. The review focuses first on an explanation of the method and second on presenting a comprehensive corpus covering available studies that have applied dynamic electrochemical impedance spectroscopy for the purpose of preventing corrosion phenomena. This chapter defines the merits of this novel approach compared with the conventional electrochemical impedance spectroscopy method.

  • Electrochemical glucose sensor based on the glucose oxidase entrapped in chitosan immobilized onto laser-processed Au-Ti electrode
    • Wiktoria Lipińska
    • Katarzyna Siuzdak
    • Jakub Karczewski
    • Anna Dołęga
    • Katarzyna Grochowska
    2021 SENSORS AND ACTUATORS B-CHEMICAL

    The study on novel electrode material composed of structured titanium foil with embedded Au nanoparticles and modified with chitosan with entrapped glucose oxidase is presented. To confirm the successful immobilization of glucose oxidase FT-IR analysis was performed. The response of electrodes were tested towards glucose in the presence of different interference compounds and biological fluids. The prepared material exhibits excellent performance for glucose detection with a wide linear range, high sensitivity and very low limit of detection.

  • Electrochemical simulation of metabolic reduction and conjugation reactions of unsymmetrical bisacridine antitumor agents, C-2028 and C-2053
    • Agnieszka Potęga
    • Szymon Paczkowski
    • Ewa Paluszkiewicz
    • Zofia Mazerska
    2021 Pełny tekst JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS

    Electrochemistry (EC) coupled with analysis techniques such as liquid chromatography (LC) and mass spectrometry (MS) has been developed as a powerful tool for drug metabolism simulation. The application of EC in metabolic studies is particularly favourable due to the low matrix contribution compared to in vitro or in vivo biological models. In this paper, the EC(/LC)/MS system was applied to simulate phase I metabolism of the representative two unsymmetrical bisacridines (UAs), named C-2028 and C-2053, which contain nitroaromatic group susceptible to reductive transformations. UAs are a novel potent class of antitumor agents of extraordinary structures that may be useful in the treatment of difficult for therapy human solid tumors such as breast, colon, prostate, and pancreatic tumors. It is considered that the biological action of these compounds may be due to the redox properties of the nitroaromatic group. At first, the relevant conditions for the electrochemical conversion and product identification process, including the electrode potential range, electrolyte composition, and working electrode material, were optimized with the application of 1-nitroacridine as a model compound. Electrochemical simulation of C-2028 and C-2053 reductive metabolism resulted in the generation of six and five products, respectively. The formation of hydroxylamine m/z [M+H-14]+, amine m/z [M+H-30]+, and novel N-oxide m/z [M+H-18]+ species from UAs was demonstrated. Furthermore, both studied compounds were shown to be stable, retaining their dimeric forms, during electrochemical experiments. The electrochemical method also indicated the susceptibility of C-2028 to phase II metabolic reactions. The respective glutathione and dithiothreitol adducts of C-2028 were identified as ions at m/z 873 and m/z 720. In conclusion, the electrochemical reductive transformations of antitumor UAs allowed for the synthesis of new reactive intermediate forms permitting the study of their interactions with biologically crucial molecules.

  • Electrochemistry from first-principles in the grand canonical ensemble
    • Arihant Bhandari
    • Chao Peng
    • Jacek Dziedzic
    • Lucian Anton
    • John R. Owen
    • Denis Kramer
    • Chris-Kriton Skylaris
    2021 Pełny tekst JOURNAL OF CHEMICAL PHYSICS

    Progress in electrochemical technologies, such as automotive batteries, supercapacitors, and fuel cells, depends greatly on developing improved charged interfaces between electrodes and electrolytes. The rational development of such interfaces can benefit from the atomistic understanding of the materials involved by first-principles quantum mechanical simulations with Density Functional Theory (DFT). However, such simulations are typically performed on the electrode surface in the absence of its electrolyte environment and at constant charge. We have developed a new hybrid computational method combining DFT and the Poisson–Boltzmann equation (P–BE) capable of simulating experimental electrochemistry under potential control in the presence of a solvent and an electrolyte. The charged electrode is represented quantum-mechanically via linear-scaling DFT, which can model nanoscale systems with thousands of atoms and is neutralized by a counter electrolyte charge via the solution of a modified P–BE. Our approach works with the total free energy of the combined multiscale system in a grand canonical ensemble of electrons subject to a constant electrochemical potential. It is calibrated with respect to the reduction potential of common reference electrodes, such as the standard hydrogen electrode and the Li metal electrode, which is used as a reference electrode in Li-ion batteries. Our new method can be used to predict electrochemical properties under constant potential, and we demonstrate this in exemplar simulations of the differential capacitance of few-layer graphene electrodes and the charging of a graphene electrode coupled to a Li metal electrode at different voltages

  • Electromagnetic Field Associated With Dermoscope Magnets May Affect the Safety of Cardiac Implanted Electronic Devices Patients
    • Grzegorz Sławiński
    • Martyna Sławińska
    • Zbigniew Usarek
    • Michał Sobjanek
    • Maciej Kempa
    • Aleksandra Liżewska-Springer
    • Ewa Lewicka
    • Roman Janusz Nowicki
    • Grzegorz Raczak
    2021 Pełny tekst Frontiers in Cardiovascular Medicine

    Dermoscopy is currently used as an auxiliary tool in general dermatology. Since some commercially available dermoscopes have built-in magnets, electromagnetic interference (EMI) may occur when examining cardiac implantable electronic devices (CIED) patients. The aim of the study was to create maps of electromagnetic fields defining a safe distance in terms of EMI. The study was performed in laboratory conditions using measuring equipment specially designed for this purpose. The following dermoscopes have been tested: Illuco IDS-1100, Visiomed Luminis, Visiomed Luminis 2, Heine NC2 with and without a contact plate, DermLite DL4, and DermLite Handyscope. Measurements were made for the following set of lift-off distances: 5, 10, 20, 30, 40, 50, and 150 mm. Each 2D scan consisted of 10-line scans shifted from each other by 10 mm. The strength of the magnetic field decreased with the distance from the faceplate. The distribution of the magnetic field differed depending on the position of the magnets. The highest magnetic field was recorded in the center of the Heine NC2 faceplate (up to 8 mT). In most cases, at a distance of 10 mm, the magnetic field strength was measured below 1 mT, with the exception of Heine NC2 and Heine NC2 with a contact plate. All tested dermoscopes generated a magnetic field of <1 mT at the distance of 20 mm. The use of dermoscopes with built-in magnets may affect the functioning of CIEDs, and the impact may vary depending on the type of dermoscope.

  • Electron attachment to representative cations composing ionic liquids
    • Iwona Anusiewicz
    • Sylwia Freza
    • Maciej Bobrowski
    • Piotr Skurski
    2021 Pełny tekst JOURNAL OF CHEMICAL PHYSICS

    Using ab initio electronic structure methods with flexible atomic orbital basis sets, we investigated the electronic structure and stability of reduction products of selected representative cations (C+) constituting ionic liquids. We found that an electron attachment to such cations leads to the neutral radicals, whereas a subsequent attachment of another (i.e., excess) electron leads to adiabatically stable anions only in two cases {[P(CH3)4]- and [MeMePyr]−}. The possibility of the formation of various dimers (such as CC+, CC, and CC-) was also considered, and the resulting systems were characterized by predicting their lowest energy structures, ionization potentials, electron affinities, and susceptibilities to the fragmentation process. Among the cations studied, only the [MeMePyr] + was found to form a typical Rydberg radical (MeMePyr) and double-Rydberg anion ([MeMePyr]-), whereas the remaining cations were predicted to form neutral rad- icals of a primarily valence (MeMeIm and MePy) or mixed Rydberg-valence [P(CH3)4] character. Our calculations confirmed the stability of all CC+ and CC dimers against fragmentation yielding the corresponding monomers (the binding energies of 12.2--20.5 kcal/mol and 11.3--72.3 kcal/mol were estimated for CC+ and CC dimers, respectively). [(MeMePyr)2]- was identified as the only adiabatically stable CC- dimeric anion having its vertical electron detachment energy of 0.417 eV. We also found that in the [(MeMePyr)2]- anionic state, three outermost electrons are described by Rydberg orbitals, which results in the (σ)2 (σ*)1 configuration.

  • Electron-Induced Decomposition of Uracil-5-yl O-(N,N-dimethylsulfamate): Role of Methylation in Molecular Stability
    • Eugene Arthur-Baidoo
    • Karina Falkiewicz
    • Lidia Chomicz-Mańka
    • Anna Czaja
    • Sebastian Demkowicz
    • Karol Biernacki
    • Witold Kozak
    • Janusz Rak
    • Stephan Denifl
    2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    The incorporation of modified uracil derivatives into DNA leads to the formation of radical species that induce DNA damage. Molecules of this class have been suggested as radiosensitizers and are still under investigation. In this study, we present the results of dissociative electron attachment to uracil-5-yl O-(N,N-dimethylsulfamate) in the gas phase. We observed the formation of 10 fragment anions in the studied range of electron energies from 0–12 eV. Most of the anions were predominantly formed at the electron energy of about 0 eV. The fragmentation paths were analogous to those observed in uracil-5-yl O-sulfamate, i.e., the methylation did not affect certain bond cleavages (O-C, S-O and S-N), although relative intensities differed. The experimental results are supported by quantum chemical calculations performed at the M06-2X/aug-cc-pVTZ level of theory. Furthermore, a resonance stabilization method was used to theoretically predict the resonance positions of the fragment anions O- and CH3-.

  • Electrophoretic Deposition of Chitosan/Eudragit E 100/AgNPs Coatings for Controlled Release of Antibacterial Substance
    • Łukasz Pawłowski
    • Andrzej Zieliński
    2021

    The development of bacterial infection of the tissues surrounding an implant is one of the leading causes of implant surgery failure. In order to prevent the deposition of bacteria on the implant surface and the formation of biofilm, coatings that exhibit antibacterial properties are manufactured. However, the problem is the controlled release of the therapeutic substance from the coating over the extended life of the implant [1], [2]. Usually, the active substance is released immediately when the implant is inserted into an environment simulating human body fluids, which results in burst release phenomenon, namely, the release of a large dose of active substance in a short period of time, which may result in a toxic effect. Unfortunately, chitosan, one of the most commonly used biopolymers in controlled drug delivery systems, is unstable in neutral pH environments, readily absorbs water, and swells, resulting in rapid release of the therapeutic agent. Therefore, it is necessary to limit the dissolution rate of the chitosan coating at neutral pH. Previous studies [3] have confirmed that the addition of Eudragit E 100, a cationic copolymer based on dimethylaminoethyl methacrylate, butyl methacrylate, and methyl methacrylate in a 2:1:1 ratio, to chitosan coatings significantly reduced the degradation of these coatings in artificial saliva solution at neutral pH while maintaining high sensitivity to pH drop. Hence, a biopolymer matrix of this type should provide a good carrier for an active substance, such as metallic nanoparticles with antibacterial activity, which will be released only when inflammation of peri-implant tissues occurs. The scientific objective of this study was to fabricate a smart composite coating of chitosan/Eudragit E 100/silver nanoparticles (chit/EE100/AgNPs) on grade 2 titanium surface using variable deposition parameters such as AgNPs concentration, voltage, and deposition time by the electrophoretic method. The determinant of the process of creating such composite coatings with EE100 by electrophoretic method on the surface of Ti grade 2 has not been determined yet. No publication concerning investigations of coatings containing chitosan/EE100 with silver nanoparticles has been found. The microstructure, surface roughness, thickness, chemical and phase composition, mechanical and electrochemical properties, silver release rate at different pH, and wettability of the produced coatings were investigated...

  • Electrophoretically Deposited Chitosan/Eudragit E 100/AgNPs Composite Coatings on Titanium Substrate as a Silver Release System
    • Łukasz Pawłowski
    • Michał Bartmański
    • Aleksandra Mielewczyk-Gryń
    • Bartłomiej Cieślik
    • Grzegorz Gajowiec
    • Andrzej Zieliński
    2021 Pełny tekst Materials

    Due to the possibility of bacterial infections occurring around peri-implant tissues, it is necessary to provide implant coatings that release antibacterial substances. The scientific goal of this paper was to produce by electrophoretic deposition (EPD) a smart, chitosan/Eudragit E 100/silver nanoparticles (chit/EE100/AgNPs) composite coating on the surface of titanium grade 2 using different deposition parameters, such as the content of AgNPs, applied voltage, and time of deposition. The morphology, surface roughness, thickness, chemical and phase composition, wettability, mechanical properties, electrochemical properties, and silver release rate at different pH were investigated. Using lower values of deposition parameters, coatings with more homogeneous morphology were obtained. The prepared coatings were sensitive to the reduced pH environment.

  • Electrostatic Zipping Actuators—Analysis of the Pull-In Effect Depending on the Geometry Parameters
    • Jacek Szkopek
    • Grzegorz Redlarski
    • Arkadiusz Żak
    2021 Pełny tekst ENERGIES

    Continuous work on a new generation of actuators, referred to as artificial muscles, resulted in the initiation of work on electrostatic zipping actuators, the concept of which is derived from micro electro-mechanical devices. Despite partial knowledge of their basic operating parameters, a question remains whether electrostatic zipping actuators are able to meet the expectations in the context of generated forces and control possibilities. In order to get closer to the answer to this question, the authors of this work created a solution method using FEM, which allowed them to conduct a series of concentric contraction tests of the desired solution. In addition to the basic features of the actuators tested, such as their length, thickness and width, for the first time the size of the weld surface, to which the loading force was applied, was taken into account. The results of the investigations show the possibility of adjusting the supply voltage range to the application requirements, but most importantly, they present the variability of the pull-in strain parameter. In extreme configurations, its value increases from ~10% to ~26%. The results obtained emphasize the need for further analysis of electrostatic zipping actuators using FEM. It will make it possible to precisely define the characteristics of this technology as well as its limits. These activities will provide the ultimate answer to the potential of electrostatic zipping actuators as artificial muscles.

  • Elemental and water-insoluble organic carbon in Svalbard snow: a synthesis of observations during 2007–2018
    • Christian Zdanowicz
    • Jean-Charles Gallet
    • Mats P. Björkman
    • Catherine Larose
    • Thomas Schuler
    • Bartłomiej Luks
    • Krystyna Koziol
    • Andrea Spolaor
    • Elena Barbaro
    • Tõnu Martma
    • Ward van Pelt
    • Ulla Wideqvist
    • Johan Ström
    2021 Pełny tekst ATMOSPHERIC CHEMISTRY AND PHYSICS

    Light-absorbing carbonaceous aerosols emitted by biomass or fossil fuel combustion can contribute to amplifying Arctic climate warming by lowering the albedo of snow. The Svalbard archipelago, being near to Europe and Russia, is particularly affected by these pollutants, and improved knowledge of their distribution in snow is needed to assess their impact. Here we present and synthesize new data obtained on Svalbard between 2007 and 2018, comprising measurements of elemental (EC) and water-insoluble organic carbon (WIOC) in snow from 37 separate sites. We used these data, combined with meteorological data and snowpack modeling, to investigate the variability of EC and WIOC deposition in Svalbard snow across latitude, longitude, elevation and time. Overall, EC concentrations (CECsnow) ranged from <1.0 to 266.6 ng g−1, while WIOC concentrations (CWIOCsnow) ranged from <1 to 9426 ng g−1, with the highest values observed near Ny-Ålesund. Calculated snowpack loadings (LECsnow, LWIOCsnow) on glaciers surveyed in spring 2016 were 0.1 to 2.6 mg m−2 and 2 to 173 mg m−2, respectively. The median CECsnow and the LECsnow on those glaciers were close to or lower than those found in earlier (2007–2009), comparable surveys. Both LECsnow and LWIOCsnow increased with elevation and snow accumulation, with dry deposition likely playing a minor role. Estimated area-averaged snowpack loads across Svalbard were 1.1 mg EC m−2 and 38.3 mg WIOC m−2 for the 2015–2016 winter. An ∼11-year long dataset of spring surface snow measurements from the central Brøgger Peninsula was used to quantify the interannual variability of EC and WIOC deposition in snow. In most years, CECsnow and CWIOCsnow at Ny-Ålesund (50 m a.s.l.) were 2–5 times higher than on the nearby Austre Brøggerbreen glacier (456 m a.s.l.), and the median EC/WIOC in Ny-Ålesund was 6 times higher, suggesting a possible influence of local EC emission from Ny-Ålesund. While no long-term trends between 2011 and 2018 were found, CECsnow and CWIOCsnow showed synchronous variations at Ny-Ålesund and Austre Brøggerbreen. When compared with data from other circum-Arctic sites obtained by comparable methods, the median CECsnow on Svalbard falls between that found in central Greenland (lowest) and those in continental sectors of European Arctic (northern Scandinavia, Russia and Siberia; highest), which is consistent with large-scale patterns of BC in snow reported by surveys based on other methods.

  • Elemental composition, environment of deposition of the Lower Carboniferous Emma Fiord Formation oil shale in Arctic Canada
    • Fariborz Goodarzi
    • Nina Goodarzi
    • Aleksandra Małachowska
    2021 INTERNATIONAL JOURNAL OF COAL GEOLOGY

    The sedimentary succession of 51-m consisting of a thin coal seam (1 m) and oil shale with a marlstone and carbonate-mudstone matrix of the Lower Carboniferous (Viséan) Emma Fiord Formation located on the Grinnell Peninsula, Devon Island, Arctic Canada was examined. The techniques used include reflected light microscopy, and instrumental neutron activation analysis (INAA) for elemental concentration, and inductively coupled plasma emission spectrometry (ICPES) for boron concentration.The coal and oil shale was deposited in a lacustrine, freshwater environment. Due to the climatic variation, two types of oil shale were developed based on the amount of precipitation.One with carbonate-mudstone matrix, with high calcite (75%) and low TOC (1.14–1.87%) content, a marlstone-dominated matrix with high aluminosilicate (64%) and TOC (16.4–53.6%). Oil shale from Emma Fiord experienced a slow rate of sedimentation and terrestrial flux as determined using Th/K/ Na/K, ratios Mn/Ca ratio to Ca respectively, and compared to the oil shale of Carboniferous age deposited in a lacustrine environment with a regular rate of recharge/discharge.The redox conditions for the Emma Fiord oil shale indicate anoxic to dysoxic conditions based on the variation of Cr and Ni + V, as well as fluctuation of V/Cr ratio and Cr.Thorium and U systematics indicate that U is more concentrated in oil shale with marlstone matrix and is associated with clay minerals and organic matter (OM), similar to the Carboniferous oil shale from the Big Marsh. The authigenic U is associated with TOC content and is higher for oil shale with the marlstone matrix.The variation of U with TOC and the hydrogen index (HI) indicates both paleo-productivity and preservation and is higher for oil shale with the marlstone matrix.The concentration of rare earth elements (REEs) is 95% due to the presence of light rare earth elements (LREEs) in both oil shale with marlstone and carbonate-mudstone matrices.The REES were normalized to the post-Archean average shale (PAAS). The high volatile bituminous coal at the base of the oil shale sections displays a flat, featureless pattern. The oil shale with a carbonate matrix decreases slightly from light rare earth elements (LREEs) to heavy rare earth elements (HREES).In contrast, the REEs concentration for oil shale with the marlstone matrix decreases more sharply from the LREEs (La-Eu) to HREEs (Tb-Lu). It displays a weak negative Eu anomaly typical of the upper continental crust.

  • Embedded gas sensing setup for air samples analysis
    • Andrzej Kwiatkowski
    • Katarzyna Drozdowska
    • Janusz Smulko
    2021 Pełny tekst REVIEW OF SCIENTIFIC INSTRUMENTS

    This paper describes a measurement setup (eNose) designed to analyze air samples containing various volatile organic compounds (VOCs). The setup utilizes a set of resistive gas sensors of divergent gas selectivity and sensitivity. Some of the applied sensors are commercially available and were proposed recently to reduce their consumed energy. The sensors detect various VOCs at sensitivities determined by metal oxide sensors’ technology and operating conditions. The setup can utilize prototype gas sensors, made of resistive layers of different compositions, as well. Their properties can be modulated by selecting operating temperature or using UV light irradiation. The unit is controlled by an embedded system M5Stack Core2 ESP32 IoT. We used this development kit to program the measurement procedure and data recording fastly. The setup utilizes an aluminum gas chamber of a volume of 220 ml, a set of electrical valves to introduce there an air sample with the help of an electrical micropump. The handling of the setup was simplified to a selection of a few operations by touch screen only without a necessity of extra training. The recorded data are saved in a memory card for further processing. The evolved setup can be upgraded to apply more advanced data processing by utilizing WiFi or Bluetooth connection. The control program was prepared using the Arduino IDE software environment and can be further advanced with ease. The applied materials and the established measurement procedure can use various air samples, including exhaled breath samples for patients’ screening check-ups. We applied the same time of 10 min for response and recovery, acceptable for practical use.

  • Embedded Representations of Wikipedia Categories
    • Jan Majkutewicz
    • Julian Szymański
    • Andrzej Sobecki
    • Higinio Mora
    • David Gil
    2021

    In this paper, we present an approach to building neural representations of the Wikipedia category graph. We test four different methods and examine the neural embeddings in terms of preservation of graphs edges, neighborhood coverage in representation space, and their influence on the results of a task predicting parent of two categories. The main contribution of this paper is application of neural representations for improving the structure of Wikipedia categories graph. We also show that a neural representation based solely on categories’ names can be an alternative to the other representations build using more complex approaches.

  • EM-Driven Multi-Objective Optimization of a Generic Monopole Antenna by Means of a Nested Trust-Region Algorithm
    • Adrian Bekasiewicz
    • Sławomir Kozieł
    • Piotr Płotka
    • Krzysztof Zwolski
    2021 Pełny tekst Applied Sciences-Basel

    Antenna structures for modern applications are characterized by complex and unintuitive topologies that are difficult to develop when conventional experience-driven techniques are of use. In this work, a method for automatic generation of antenna geometries in a multi-objective setup has been proposed. The approach involves optimization of a generic spline-based radiator with adjustable number of parameters using a nested trust-region-based algorithm. The latter iter-atively increases dimensionality of the radiator in order to gradually improve its performance. The method has been used to generate a set of nine antenna designs representing a trade-off between minimization of reflection within 3.1 GHz to 10.6 GHz and reduction of size. The properties of optimized designs vary along the Pareto set from –10 dB to –20 dB, and from 230 mm2 to 757 mm2 for the first, and the second objective, respectively. The presented design approach has been validated against a genuine population-based optimization routine. Furthermore, the smallest Pareto-optimal design has been compared to the antennas from the literature.

  • Emerging oxidized and defective phases in low-dimensional CrCl3
    • Dario Mastrippolito
    • Luca Ottaviano
    • Jingsong Wang
    • Jinjin Yang
    • Faming Gao
    • Mushtaq Ali
    • Gianluca D'Olimpio
    • Antonio Politano
    • Stefano Palleschi
    • Shafaq Kazim
    • Roberto Gunnella
    • Andrea DiCicco
    • Anna Sgarlata
    • Judyta Strychalska-Nowak
    • Tomasz Klimczuk
    • Robert J. Cava
    • Luca Lozzi
    • Gianni Profeta
    2021 Pełny tekst Nanoscale Advances

    Two-dimensional (2D) magnets such as chromium trihalides CrX3 (X ¼ I, Br, Cl) represent a frontier for spintronics applications and, in particular, CrCl3 has attracted research interest due its relative stability under ambient conditions without rapid degradation, as opposed to CrI3. Herein, mechanically exfoliated CrCl3 flakes are characterized at the atomic scale and the electronic structures of pristine, oxidized, and defective monolayer CrCl3 phases are investigated employing density functional theory (DFT) calculations, scanning tunneling spectroscopy (STS), core level X-ray photoemission spectroscopy (XPS), and valence band XPS and ultraviolet photoemission spectroscopy (UPS). As revealed by atomically resolved transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis, the CrCl3 flakes show spontaneous surface oxidation upon air exposure with an extrinsic long-range ordered oxidized O–CrCl3 structure and amorphous chromium oxide formation on the edges of the flakes. XPS proves that CrCl3 is thermally stable up to 200 C having intrinsically Cl vacancy-defects whose concentration is tunable via thermal annealing up to 400 C. DFT calculations, supported by experimental valence band analysis, indicate that pure monolayer (ML) CrCl3 is an insulator with a band gap of 2.6 eV, while the electronic structures of oxidized and Cl defective phases of ML CrCl3, extrinsically emerging in exfoliated CrCl3 flakes, show in-gap spin-polarized states and relevant modifications of the electronic band structures.

  • Emerging strategies for enhancing detection of explosives by artificial olfaction
    • Wasilewski Tomasz
    • Jacek Gębicki
    2021 MICROCHEMICAL JOURNAL

    Explosives detection systems need to be able to reliably detect a wide range of explosive materials and their vapours. The continued development and improvement of artificial olfaction techniques, including electronic nose (EN), remains important to overcome existing challenges and meet requirements posed by new improvements in the field of explosives. There is an increasingly popular trend aimed at improvement of fundamental metrological parameters of sensors for the construction of sensor arrays for the detection of ultralow target analytes. Even after decades of developments, applications of artificial olfaction instruments aimed at selective and sensitive detection of trace quantities of explosives constitute still a difficult and challenging problem. Essential aspects of artificial olfaction were theoretically discussed with an emphasis on evaluation of enhancing sensors parameters in the detection of explosives. Progress in nanotechnology and prospects in mimicking biological sense of smell successively remove the boundaries of artificial olfaction technologies. A tendency towards improved selectivity and specificity of the sensors is evident. Elaboration of novel sensing materials, data processing systems and sampling procedures are the main approaches to increase sensors’ major metrological parameters. Implementation of designed construction solutions in practice and meeting particular requirements are still a bottleneck in the commercialization process. The demonstration of achievements in artificial olfaction technology during the last couple of years is reviewed and different strategies to enhance their properties are suggested. Moreover, recent technological advancement including bio-inspired strategies, robots, drones and smartphones were described. Finally, we discuss emerging approaches to solve problems accompanied with direct and discriminative detection of explosives and outline future perspectives related to this topic.

  • EMI attenuation in a DC-DC buck converter using GaN HEMT
    • Pawel B. Derkacz
    • Piotr Musznicki
    • Piotr Chrzan
    2021 Pełny tekst IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS

    A dc-dc buck converter using gallium nitride (GaN) high electron mobility transistors (HEMT) is experimentally investigated at the discontinuous current mode (DCM) and at the triangular current mode (TCM) operation. The paper objective is to specify the power conversion efficiency and attenuation of common mode (CM) and differential mode (DM) noise voltage, measured at the line impedance stabilization network (LISN) for compared control strategies. Zero voltage switching achieved for the TCM operation improves efficiency with reference to the DCM operation. However, significant attenuation of electromagnetic interference (EMI) spectra is obtained for TCM operation with capacitive snubber. Sizing of capacitor snubber dependent on parasitic inductances of commutation circuit and rapid switching of GaN HEMTs are illustrated.

  • Emissions and toxic units of solvent, monomer and additive residues released to gaseous phase from latex balloons
    • Mariusz Marć
    • Stefan Tsakovski
    • Marek Tobiszewski
    2021 Pełny tekst ENVIRONMENTAL RESEARCH

    This study describes the VOCs emissions from commercially available latex balloons. Nine compounds are determined to be emitted from 13 types of balloons of different colors and imprints in 30 and 60°C. The average values of total volatile organic compounds (TVOCs) emitted from studied samples ranged from 0.054 up to 7.18 μg∙g-1 and from 0.27 up to 36.13 μg∙g-1 for 30oC and 60oC, respectively. The dataset is treated with principal component analysis (PCA) and multiple curve resolution (MCR) to characterize its internal patterns. Here two groups on compounds are recognized – the first one related to balloon material, the second one being emissions of compounds previously adsorbed on balloon material. The toxicity assessment of MCR modeled balloons’ emissions was performed by toxic unit (TU) approach. The obtained TUs were summed to give toxicity emission assessment. The incorporation of TUs allows to identify the balloons with the most toxic emissions– imprinted ones in 60°C. The compounds of the highest TUs are hexanal and benzene. FTIR analysis shows that all balloons are made of the same polymeric material – isoprene, so all differences in emissions are related to different additives like pigments, imprints or these responsible for opaqueness. Analyzing the obtained research results it was noticed that latex balloons might be considered as an important source of emission of aliphatic and monoaromatic hydrocarbons to the gaseous phase.

  • Empirical analyses of robustness of the square Msplit estimation
    • Zbigniew Wiśniewski
    • Marek Zienkiewicz
    2021 Journal of Applied Geodesy

    The paper presents Msplit estimation as an alternative to methods in the class of robust M-estimation. The analysis conducted showed that Msplit estimation is highly efficient in the identification of observations encumbered by gross errors, especially those of small or moderate values. The classical methods of robust estimation provide then unsatisfactory results. Msplit estimation also shows high robustness to single gross errors of large values. The presented analysis of Msplit estimators’ robustness is of a chiefly empirical nature and is based on the example of a simulated levelling network and a real angular-linear network. Using the Monte Carlo method, mean success rates for outlier identification were determined and the courses of empirical influence functions were specified. The outcomes of the analysis were compared with the relevant values achieved via selected methods of robust M-estimation.

  • Employees With Autism Spectrum Disorders in the Digitized Work Environment: Perspectives for the Future
    • Michał Tomczak
    2021 Pełny tekst Journal of Disability Policy Studies

    The aim of this article is to examine the opportunities for employees with autism spectrum disorders (ASDs), arising from digital technology (DT) development. The author discusses assistive technology (AT) as a mean of creating a better work environment, making the digitized workplace more friendly for people with ASD. A possible solution of communication problems is replacing the interpersonal communication between employees with electronic (non-direct) forms of communication, such as online communicators or chatbots. Another solution is the implementation of wearable electronic systems, monitoring stress levels and facilitating effective stress control. In the future, the whole digitized workplace could be designed according to a “smart workplace” concept. Sensors recording various human body parameters could be connected to a network with sensors recording physical parameters of the work environment (temperature, humidity,noise, smell, sunlight exposure) and also with controllers of its values, adjusting it dynamically to reduce distracting factors. As a result, communication, stress management, and sensory sensitiveness problems could be limited, improving the work comfort of people with ASD, and their colleagues. The pertinence of solutions proposed was also confirmed by the experts interviewed in the field who were asked to assess it in the context of future implementation.

  • Enabling simultaneous redox transformation of toxic chromium(VI) and arsenic(III) in aqueous media—A review
    • Yu Fu
    • Lingli Wang
    • Wenya Peng
    • Qingya Fan
    • Qingchao Li
    • Yongxia Dong
    • Yunjiao Liu
    • Grzegorz Boczkaj
    • Zhaohui Wang
    2021 JOURNAL OF HAZARDOUS MATERIALS

    Simultaneous conversion of most harmful As(III) and Cr(VI) to their less toxic counterparts is environmentally desirable and cost-effective. It has been confirmed that simultaneous oxidation of As(III) to As(V) and reduction of Cr(VI) to Cr(III) can occur via free radical or mediated electron transfer processes. While Cr(VI) is reduced by reacting with H•, eaq−, photoelectron directly or undergoing ligand exchange with H2O2 and SO32−, As(III) is oxidized by HO•, SO4•−, O2•−, and holes (h+) in free radical process. The ability to concentrate Cr and As species on heterogeneous interface and conductivity determining the co-conversion efficiency in mediated electron transfer process. Acidity has positive effect on these co-conversion, while mediated electron transfer process is not much affected by dissolved oxygen (O2). Organic compounds (e.g., oxalate, citrate and phenol) commonly favor Cr(VI) reduction and inhibit As(III) oxidation. To better understand the trends in the existing data and to identify the knowledge gaps, this review elaborates the complicated mechanisms for co-conversion of As(III) and Cr(VI) by various methods. Some challenges and prospects in this active field are also briefly discussed.

  • Encapsulation of Amikacin into Microparticles Based on Low-Molecular-Weight Poly(lactic acid) and Poly(lactic acid-co-polyethylene glycol)
    • Marta Glinka
    • Katerina Filatova
    • Justyna Kucińska-Lipka
    • Eva Domincova Bergerova
    • Andrzej Wasik
    • Vladimir Sedlařík
    2021 Pełny tekst MOLECULAR PHARMACEUTICS

    The aim of this study was to fabricate novel microparticles (MPs) for efficient and long-term delivery of amikacin (AMI). The emulsification method proposed for encapsulating AMI employed low-molecular-weight poly(lactic acid) (PLA) and poly(lactic acid-co-polyethylene glycol) (PLA−PEG), both supplemented with poly(vinyl alcohol) (PVA). The diameters of the particles obtained were determined as less than 30 μm. Based on an in-vitro release study, it was proven that the MPs (both PLA/PVA- and PLA−PEG/PVA-based) demonstrated long-term AMI release (2 months), the kinetics of which adhered to the Korsmeyer−Peppasmodel. The loading efficiencies of AMI in the study were determined at the followings levels: 36.5±1.5 μg/mg for the PLA-based MPs and 106±32 μg/mg forthe PLA−PEG-based MPs. These values were relatively high and draw parallels with studies published on the encapsulation of aminoglycosides. The MPs provided antimicrobial action against the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae bacterial strains. The materials were also comprehensively characterized by the following methods: differential scanning calorimetry; gel permeation chromatography; scanning electron microscopy; Fourier transform infrared spectroscopy−attenuated total reflectance; energy-dispersive X-rayfluorescence; and Brunauer−Emmett−Teller surface area analysis. The findings of this study contribute toward discerning new means for conducting targeted therapy with polar, broad spectrum antibiotics.

  • Encapsulation of an anticancer drug Isatin inside a host nano-vehicle SWCNT: a molecular dynamics simulation
    • Maryam Zarghami Dehaghani
    • Farrokh Yousefi
    • Farzad Seidi
    • Babak Bagheri
    • Amin Hamed Mashhadzadeh
    • Ghasem Naderi
    • Amin Esmaeili
    • Otman Abida
    • Sajjad Habibzadeh
    • Mohammad Saeb
    • Maksym Rybachuk
    2021 Pełny tekst Scientific Reports

    The use of carbon nanotubes as anticancer drug delivery cargo systems is a promising modality as they are able to perforate cellular membranes and transport the carried therapeutic molecules into the cellular components. Our work describes the encapsulation process of a common anticancer drug, Isatin (1H-indole-2,3-dione) as a guest molecule, in a capped single-walled carbon nanotube (SWCNT) host with chirality of (10,10). The encapsulation process was modelled, considering an aqueous solution, by a molecular dynamics (MD) simulation under a canonical NVT ensemble. The interactions between the atoms of Isatin were obtained from the DREIDING force filed. The storage capacity of the capped SWCNT host was evaluated to quantify its capacity to host multiple Isatin molecules. Our results show that the Isatin can be readily trapped inside the volume cavity of the capped SWCNT and it remained stable, as featured by a reduction in the van der Waals forces between Isatin guest and the SWCNT host (at approximately − 30 kcal mol−1) at the end of the MD simulation (15 ns). Moreover, the free energy of encapsulation was found to be − 34 kcal mol−1 suggesting that the Isatin insertion procedure into the SWCNT occurred spontaneously. As calculated, a capped SWCNT (10,10) with a length of 30 Å, was able to host eleven (11) molecules of Isatin, that all remained steadily encapsulated inside the SWCNT volume cavity, showing a potential for the use of carbon nanotubes as drug delivery cargo systems.

  • Endothelial Dysfunction Driven by Hypoxia—The Influence of Oxygen Deficiency on NO Bioavailability
    • Anna Janaszak-Jasiecka
    • Anna Siekierzycka
    • Agata Płoska
    • Iwona T. Dobrucki
    • Leszek Kalinowski
    2021 Pełny tekst Biomolecules

    Cardiovascular diseases (CVDs) are the leading cause of death worldwide. The initial stage of CVDs is characterized by endothelial dysfunction, defined as the limited bioavailability of nitric oxide (NO). Thus, any factors that interfere with the synthesis or metabolism of NO in endothelial cells are involved in CVD pathogenesis. It is well established that hypoxia is both the triggering factor as well as the accompanying factor in cardiovascular disease, and diminished tissue oxygen levels have been reported to influence endothelial NO bioavailability. In endothelial cells, NO is produced by endothelial nitric oxide synthase (eNOS) from L-Arg, with tetrahydrobiopterin (BH4) as an essential cofactor. Here, we discuss the mechanisms by which hypoxia affects NO bioavailability, including regulation of eNOS expression and activity. What is particularly important is the fact that hypoxia contributes to the depletion of cofactor BH4 and deficiency of substrate L-Arg, and thus elicits eNOS uncoupling—a state in which the enzyme produces superoxide instead of NO. eNOS uncoupling and the resulting oxidative stress is the major driver of endothelial dysfunction and atherogenesis. Moreover, hypoxia induces impairment in mitochondrial respiration and endothelial cell activation; thus, oxidative stress and inflammation, along with the hypoxic response, contribute to the development of endothelial dysfunction.

  • ENERGIEEFFIZIENZ DER ZAHLUNGSOPERATIONEN
    • Tetiana Osadcha
    • Oleksandr Melnychenko
    2021 Pełny tekst

    Heute kannman nach verschiedenen Schätzungen mehr als zehn Möglichkeiten nutzen, um Einzelhandelswaren, Dienstleistungen oder geleistete Arbeit zu bezahlen. Die beliebtesten, bedeutendsten und sensibelsten sind Bargeld-und bargeldlose Zahlungen. Als die modernste kann man Kryptowährungzahlungen schätzen. Jede Zahlungsart ist mit Zeit-und Energiekosten für ihre Wartung und dementsprechend mit finanziellen Kosten verbunden. Etwa die Hälfte von diesen Kosten wird von Einzelhandelsgeschäften und Banken getragen. Der Zeitaufwand des Kassierers für Zahlungsdienste verursacht erhebliche Energiekosten für Handelsunternehmen und insgesamt für die Gesellschaft aufgrund der Unvollkommenheit der Zahlungsmittel und der Zahlungsinfrastruktur,. In diesem Bericht konzentrieren wiruns auf die Energieeffizienz von Zahlungsinstrumenten, von denen das schnellste bargeldlose Zahlungsmittel durch die Einführung einer besseren Zahlungsinfrastruktur noch energieeffizienter sein kann. Auch zeigen wir, dass Kryptowährung am wenigsten energieeffiziente Zahlungsmittel ist

  • ENERGY ANALYSIS OF THE PROPULSION SHAFT FATIGUE PROCESS IN A ROTATING MECHANICAL SYSTEM PART III DIMENSIONAL ANALYSIS
    • Zbigniew Korczewski
    • Konrad Marszałkowski
    2021 Pełny tekst Polish Maritime Research

    This article presents the third and last part of the problem of diagnosing the fatigue of marine propulsion shafts in terms of energy with the use of the action function, undertaken by the authors. Even the most perfect physical models of real objects, observed under laboratory conditions and developed based on the results of their research, cannot be useful in diagnostics without properly transferring the obtained results to the scale of the real object. This paper presents the method of using dimensional analyses and the Buckingham theorem (the so-called π theorem) to determine the dimensionless numbers of the dynamic similarity of the physical model of the propulsion shaft and its real ship counterpart, which enable the transfer of the results of the research on the energy processes accompanying the ship propulsion shaft fatigue from the physical model to the real object.

  • Energy Efficiency Study of Audio-video Content Consumption on Selected Android Mobile Terminals
    • Przemysław Falkowski-Gilski
    • Maciej Pańkowski
    2021

    Mobile devices are widely used by billions of users worldwide. Thanks to their main advantage, which is portability, they should be fully operational as long as possible, without the need to recharge or connect them to external power sources. This paper describes a study, carried out on four different mobile devices, with different hardware and software parameters, running the Android operating system. The research campaign involved several scenarios, including consumption of audio-visual content by different means of wireless communication (cellular and Wi-Fi), designed to best reflect the common daily use of a modern smartphone. Those scenarios were based on a user experience survey conducted at the beginning of the study. Obtained results illustrate user preferences as well as resource consumption of multimedia on different devices with varying distribution of the Android OS.

  • Energy Losses Due to Imperfect Payment Infrastructure and Payment Instruments
    • Oleksandr Melnychenko
    2021 Pełny tekst ENERGIES

    One of the strategic objectives of the European Union is a reduction in greenhouse gas emissions and improvement of energy efficiency by at least 32.5% in different areas of the economy by 2030. However, little is known about the impact of payment in retail on energy consumption. The purpose of this paper is to assess the chain of losses of time and energy, and therefore financial losses, that occur due to the imperfection of payment infrastructure and instruments using data of cashiers’ working time. The research is based on a regression analysis method, where the energy cost per payment transaction is considered in this study as a function of the number of customers per hour and the energy cost. The results of the panel models highlight that the number of customers per hour has a negative impact on the cost of energy per payment transaction. Furthermore, modern means and methods of payment, including cryptocurrencies, do not solve the problem of the excessive time that it takes to service payments, which entails a waste of energy and money. The empirical results give valuable insights into how to best organise payment in retail to achieve lower energy costs and improve energy efficiency in payment infrastructure.

  • Enhanced electrochemical kinetics of highly-oriented (111)-textured boron-doped diamond electrodes induced by deuterium plasma chemistry
    • Anna Dettlaff
    • Michał Sobaszek
    • Tomasz Klimczuk
    • Robert Bogdanowicz
    2021 Pełny tekst CARBON

    Novel highly-oriented (111)-textured boron-doped diamond electrodes (BDDD) featuring high electrochemical activity and electrode stability toward electrochemical analytics were fabricated by deuterium-rich microwave plasma CVD. The high flux deuterium plasma-induced preferential formation of (111)-faceted diamond as revealed by XRD. The highly-oriented diamond surface exhibited improved boron dopant incorporation and activation, whereas the crystals showed enhanced carrier electron acceptance and donation, which accelerated the electron transfer during electrochemical redox mediation. The standard rate constant and peak-to-peak separation E for the oxidation and reduction of the Fe(CN)63-/4- and Ru(NH3)62+/3+ redox probes reached E values of only 60.6 and 59.8 mV, respectively. The enriched electrochemical performance of the BDDD electrodes is an advantageous feature allowing them to be applied as ultrasensitive electrodes, demonstrated here by paracetamol determination. The differential pulse voltammetry results revealed an enhanced electrochemical oxidation effect for paracetamol at the deuterium-grown (111)-rich diamond electrode. A single linear range from 1 to 125 μM along with a low detection limit of 0.76 μM were achieved.

  • Enhanced photocatalytic activity of accordion-like layered Ti3C2 (MXene) coupled with Fe-modified decahedral anatase particles exposing {1 0 1} and {0 0 1} facets
    • Anna Grzegórska
    • Paweł Głuchowski
    • Jakub Karczewski
    • Jacek Ryl
    • Izabela Wysocka
    • Katarzyna Siuzdak
    • Grzegorz Trykowski
    • Katarzyna Grochowska
    • Anna Zielińska-Jurek
    2021 Pełny tekst CHEMICAL ENGINEERING JOURNAL

    New composites consisting of decahedral anatase particles exposing {001} and {101} facets coupled with accordion-like layered Ti3C2 with boosted photocatalytic activity towards phenol and carbamazepine degradation were investigated. The photocatalysts were characterized with X-ray diffraction (XRD), diffuse reflectance spectroscopy (DR/UV–Vis), Brunauer-Emmett-Teller (BET) specific surface area, Raman spectroscopy, scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) spectroscopy, emission spectroscopy, luminescence decay analysis, electrochemical impedance spectroscopy (EIS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and electrophoretic mobility measurements. The effect of hydrothermal reaction parameters on physicochemical, structural, and photocatalytic properties was studied. In all photodegradation processes, ortho-hydroxyphenol and para-hydroxyphenol were detected as the first intermediates of phenol decomposition. For the TiO2/Ti3C2(140,12) sample containing VTi, a higher concentration of para-hydroxyphenol than ortho-hydroxyphenol was observed, whereas for sample TiO2/Ti3C2(220,24) higher concentration of ortho-hydroxyphenol was noticed. The formation of surface heterojunction between {101} and {001} facets of decahedral anatase particles grown on Ti3C2 surface led to improved photoelectron transfer and enhanced photocatalytic activity towards degradation of carbamazepine - non-biodegradable and susceptible to bioaccumulation in living organisms commonly used pharmaceutical agent. Moreover, modification of TiO2/Ti3C2 surface with iron by magnetron sputtering deposition markedly improved photocatalytic activity in carbamazepine decomposition, with nearly 100% degradation in 60 min of irradiation under simulated solar light.

  • Enhancement of PUR/PIR foam thermal stability after addition of Zostera marina biomass component investigated via thermal analysis and isoconversional kinetics
    • Adrian Olejnik
    • Paulina Kosmela
    • Łukasz Piszczyk
    2021 JOURNAL OF POLYMER SCIENCE

    In the present work, a thorough thermogravimetric (TG) analysis of bio-based polyurethane–polyisocyanurate (PUR–PIR) foams in both nitrogen and oxygen atmosphere is performed. A sustainable element of the foam is a biopolyol obtained via acid-catalyzed liquefaction of Zostera marina and Enteromorpha Algae biomass. Based on isoconversional analysis and apparent activation energies, several conclusions are obtained. In contradiction to the common understanding, biopolyol based foams exhibit enhanced stability in both oxidative atmosphere and in nitrogen compared to purely petrochemical foams. Relationships between thermal stability and structure of the foams are established. Enhanced stability of bio-based foams in oxygen is attributed to two factors. First is an increased cross-linking density due to higher hydroxyl number of biopolyol compared to petrochemical one. Possibly the presence of more amount of aromatic compounds in the structure of polyols that come from lignin or aromatic ketones contribute to further enhancement of thermal stability. Those results suggest that the studied biobased foams are prospective alternatives to standard petrochemical PUR foams.

  • Enhancing Resilience of FSO Networks to Adverse Weather Conditions
    • Ilya Kalesnikau
    • Michał Pióro
    • Jacek Rak
    • Hristo Ivanov
    • Emma Fitzgerald
    • Erich Leitgeb
    2021 Pełny tekst IEEE Access

    Optical wireless networks realized by means of gigabit optical wireless communication (OWC) systems are becoming, in a variety of applications, an important alternative, or a complementary solution, to their fiber-based counterparts. However, performance of the OWC systems can be considerably degraded in periods of unfavorable weather conditions, such as heavy fog, which temporarily reduce the effective capacity of the network. In this paper, we focus on optical wireless mesh networks that use terrestrial links (called FSO – free-space optical – links) composed of several parallel full-duplex FSO systems, and present two complementary solutions that together provide a means to maximize network traffic performance in various weather conditions encountered during network operation. The first solution is a method for estimating the degradation of the effective FSO link capacity in adverse weather conditions such as fog, rain and snow (called the weather states in this paper). The second solution is an optimization model aiming at maximizing the network traffic throughput for a given list of weather states, derived from the conducted measurements. The model assumes the so-called affine flow thinning (AFT) traffic routing and protection mechanism capable of controlling the end-to-end traffic flows in response to fluctuations of capacity available on FSO links caused by changing weather conditions. The proposed link capacity modeling approach and the elaborated optimization model are verified through an exhaustive numerical study, illustrating the trade-off between the increase of traffic performance of the FSO networks and the corresponding cost of additional OWC systems.

  • Ensuring sustainable development of urban public transport: A case study of the trolleybus system in Gdynia and Sopot (Poland)
    • Marcin Wołek
    • Michał Wolański
    • Mikołaj Bartłomiejczyk
    • Olgierd Wyszomirski
    • Krzysztof Grzelec
    • Katarzyna Hebel
    2021 Pełny tekst JOURNAL OF CLEANER PRODUCTION

    Electromobility is a vital tool in reducing the environmental impact of transportation. A technologically mature means of public transport is the trolleybus. Based on a case study of the Polish cities of Gdynia and Sopot, this paper explores the factors that influence the development of the trolleybus system. Recent developments of in-motion charging (IMC) technology are analysed what provides a new analytical framework for the trolleybus development, bringing the original path for the expansion of the electromobility in urban areas without overhead lines. The use of an economic model has made it possible to assess the total lifecycle costs of trolleybuses and to specify a threshold that makes it more cost-effective than diesel buses. Operational data allows for a simulation that reveals the minimal rate of catenary coverage of a route in terms of speed and two charging power values. Results indicate that after including external costs into the economic calculation, trolleybus transport is economically efficient, although the energy mix is an important factor. In-motion charging trolleybus can be seen as a compromise solution between capital costs and battery capacity and is recommended for cities already operating this system.