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Gdańsk University of Technology

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  • Pulse-Width Modulation of Power Electronic DC–AC Converter
    • Atif Iqbal
    • Arkadiusz Lewicki
    • Marcin Morawiec
    2021

    The Second Edition of High Performance Control of AC Drives with Matlab®/Simulink delivers an updated and thorough overview of topics central to the understanding of AC motor drive systems. The book includes new material on medium voltage drives, covering state-of-the-art technologies and challenges in the industrial drive system, as well as their components, and control, current source inverter-based drives, PWM techniques for multilevel inverters, and low switching frequency modulation for voltage source inverters.

  • Pulse-Width Modulation Template for Five-Level Switch-Clamped H-Bridge-Based Cascaded Multilevel Inverter
    • Charles Ikechukwu Odeh
    • Dmytro Kondratenko
    • Arkadiusz Lewicki
    • Marcin Morawiec
    • Andrzej Jąderko
    • Janusz Baran
    2021 Full text ENERGIES

    This article presents a carrier-based pulse-width modulation (PWM) template for a 5-level, H bridge-based cascaded multilevel inverter (MLI). The developed control concept generates adequate modulation template for this inverter topology wherein a sinusoidal modulating waveform is modified to fit in a single triangular carrier signal range. With this modulation approach, classical multiplicity and synchronization of the triangular carrier signals criterion for the extension of sinusoidal pulse-width modulation, SPWM, to several cascaded 5-level, H-bridge-based MLI topology are removed. The proposed template can be used on the inverter configuration of any level with no further control modification. Nearly even distribution of switching pulses and equalized individual cascaded cell output power were achieved with the proposed modulation scheme. Three 5-level, H-bridge-based MLI units were cascaded for 1-phase, 13-level inverter operation; simulation and experimental results are adequately presented.

  • Pyrolysis of Pruning Residues from Various Types of Orchards and Pretreatment for Energetic Use of Biochar
    • Paweł Kazimierski
    • Paulina Hercel
    • Tomasz Suchocki
    • Jakub Smoliński
    • Agnieszka Pladzyk
    • Dariusz Kardaś
    • Justyna Łuczak
    • Katarzyna Januszewicz
    2021 Full text Materials

    The routine pruning and cutting of fruit trees provides a considerable amount of biowaste each year. This lignocellulosic biomass, mainly in the form of branches, trunks, rootstocks, and leaves, is a potential high-quality fuel, yet often is treated as waste. The results of a feasibility study on biochar production by pyrolysis of residues from orchard pruning were presented. Three types of biomass waste were selected as raw materials and were obtained from the most common fruit trees in Poland: apple (AP), pear (PR), and plum (PL) tree prunings. Two heating rates and three final pyrolysis temperatures were applied. For the slow (SP) and fast pyrolysis (FP) processes, the heating rates were 15 °C/min and 100 °C/min, respectively. The samples were heated from 25 °C up to 400, 500, and 600 °C. Chemical analyses of the raw materials were conducted, and the pyrolysis product yields were determined. A significant rise of higher heating value (HHV) was observed for the solid pyrolysis products, from approximately 23.45 MJ/kg for raw materials up to approximately 29.52 MJ/kg for pyrolysis products at 400 °C, and 30.53 MJ/kg for pyrolysis products at 600 °C. Higher carbon content was observed for materials obtained by fast pyrolysis conducted at higher temperatures

  • QUALITY GAPS IN HIGHER EDUCATION FROM THE PERSPECTIVE OF STUDENTS
    • Piotr Grudowski
    • Katarzyna, Szczepańska
    2021 Full text Foundations of Management

    The presented research work relates to the category of quality in higher education. This article aims to present the determinants of the quality of education in the context of international standards. The background of the considerations is the Bologna Declaration and the European Higher Education Area. The results of the research carried out with the use of the nominal group method and the data analysis carried out based on the SERVQUAL model for education revealed groups of quality determi-nants that are not included in the standards of internal quality assurance. It has been found that the prin-ciple of autonomy of universities in the European Higher Education Area is a sufficient basis to include the determinants of the quality of education identified by internal stakeholders of a given university in the internal quality of education assurance system.

  • Quality of Satellite Communication in Selected Mobile Android Smartphones
    • Przemysław Falkowski-Gilski
    2021 Full text Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

    Today, thanks to mobile devices, satellite communication is available to anyone and everywhere. Gaining information on one’s position using GNSS (Global Navigation Satellite Systems), particularly in unknown urban environments, had become an everyday activity. With the widespread of mobile devices, particularly smartphones, each person can obtain information considering his or her location anytime and everywhere. This paper is focused on a study, considering the quality of satellite communication in case of selected mobile terminals. It describes a measurement campaign carried out in varying urban environments, including a set of Android-powered smartphones coming from different manufacturers. Based on this, respective conclusions and remarks are given, which can aid consumers as well as device manufacturers and application developers.

  • Quantitative fluorescent determination of DNA – Ochratoxin a interactions supported by nitrogen-vacancy rich nanodiamonds
    • Wioleta Białobrzeska
    • Maciej Głowacki
    • Monika Janik
    • Mateusz Ficek
    • Krzysztof Pyrchla
    • Sawczak Mirosław
    • Robert Bogdanowicz
    • Natalia Malinowska
    • Sabina Żołędowska
    • Dawid Nidzworski
    2021 Full text JOURNAL OF MOLECULAR LIQUIDS

    Ochratoxin A (OTA) is a hazardous contaminant of a large variety of plant and animal originated food. Herein, we report an interaction of OTA with calf thymus DNA (ct DNA) on the nanodiamond surface. We employed multispectroscopic techniques to elucidate the binding mechanism of OTA with ct DNA. The fluorescence and UV–Vis spectroscopy results show that OTA binds to ds ct DNA and forms complexes. We obtained the binding constants of OTA and ct DNA using fluorescence quenching and UV–Vis spectroscopy. The binding constant (Kb) for the interaction of OTA with ct DNA was determined using spectroscopic methods and was determined as 3.27 × 105 M−1 (UV–Vis) and 8.12 × 105 M−1 (fluorescence) for nanodiamond in green tea beverage OTA. Performed analyses directly indicate that OTA can interact with calf thymus DNA in a groove-binding mode as proved by the hyperchromic effect of the absorption spectra. This study of OTA–ct DNA interaction may provide novel insights into the toxicological effect of the mycotoxins.

  • Quantitative Risk Assessment in Construction Disputes Based on Machine Learning Tools
    • Hubert Anysz
    • Magdalena Apollo
    • Beata Grzyl
    2021 Full text Symmetry-Basel

    A high monetary value of the construction projects is one of the reasons of frequent disputes between a general contractor (GC) and a client. A construction site is a unique, one-time, and single-product factory with many parties involved and dependent on each other. The organizational dependencies and their complexity make any fault or mistake propagate and influence the final result (delays, cost overruns). The constant will of the parties involved results in completing a construction object. The cost increase, over the expected level, may cause settlements between parties difficult and lead to disputes that often finish in a court. Such decision of taking a client to a court may influence the future relations with a client, the trademark of the GC, as well as, its finance. To ascertain the correctness of the decision of this kind, the machine learning tools as decision trees (DT) and artificial neural networks (ANN) are applied to predict the result of a dispute. The dataset of about 10 projects completed by an undisclosed contractor is analyzed. Based on that, a much bigger database is simulated for automated classifications onto the following two classes: a dispute won or lost. The accuracy of over 93% is achieved, and the reasoning based on results from DT and ANN is presented and analyzed. The novelty of the article is the usage of in-company data as the independent variables what makes the model tailored for a specific GC. Secondly, the calculation of the risk of wrong decisions based on machine learning tools predictions is introduced and discussed

  • Quantum and carbon dots conjugated molecularly imprinted polymers as advanced nanomaterials for selective recognition of analytes in environmental, food and biomedical applications
    • Monika Sobiech
    • Piotr Luliński
    • Piotr Paweł Wieczorek
    • Mariusz Marć
    2021 TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    Samples with complex matrix analyzed during explanation of pathogenesis of various diseases and food or environmental monitoring request advanced analytical and instrumental devices. Among the materials used for described purposes, quantum (QDs) or carbon dots (CDs) layered by molecularly imprinted polymer (MIP) shells have gained widespread attention. Unique optical and physicochemical properties of QDs/CDs together with high MIPs selectivity make the QD/CD-MIP conjugates capable of adsorbing specific target molecules e such a binding event is then transduced as the optical signal of the response by the QDs/CDs. This review includes brief introduction on principles of imprinting process, QD/CD properties and QD/CD-MIP preparation techniques. Then, recent advancement of QD/CD-MIP in bioanalysis including environmental, biological and food samples investigations are summarized and emphasized. Finally, current limits of QD/CD-MIPs are defined and prospects are outlined to intensify the capability of QD/CD-MIP in future bioanalytical procedures

  • Quantum Dots as a Good Carriers of Unsymmetrical Bisacridines for Modulating Cellular Uptake and the Biological Response in Lung and Colon Cancer Cells
    • Joanna Pilch
    • Patrycja Kowalik
    • Piotr Bujak
    • Anna M. Nowicka
    • Ewa Augustin
    2021 Full text Nanomaterials

    Nanotechnology-based drug delivery provides a promising area for improving the efficacy of cancer treatments. Therefore, we investigate the potential of using quantum dots (QDs) as drug carriers for antitumor unsymmetrical bisacridine derivatives (UAs) to cancer cells. We examine the influence of QD–UA hybrids on the cellular uptake, internalization (Confocal Laser Scanning Microscope), and the biological response (flow cytometry and light microscopy) in lung H460 and colon HCT116 cancer cells. We show the time- dependent cellular uptake of QD–UA hybrids, which were more efficiently retained inside the cells compared to UAs alone, especially in H460 cells, which could be due to multiple endocytosis pathways. In contrast, in HCT116 cells, the hybrids were taken up only by one endocytosis mechanism. Both UAs and their hybrids induced apoptosis in H460 and HCT116 cells (to a greater extent in H460). Cells which did not die underwent senescence more efficiently following QDs–UAs treatment, compared to UAs alone. Cellular senescence was not observed in HCT116 cells following treatment with both UAs and their hybrids. Importantly, QDgreen/red themselves did not provoke toxic responses in cancer or normal cells. In conclusion, QDs are good candidates for targeted UA delivery carriers to cancer cells while protecting normal cells from toxic drug activities.

  • Quantum randomness protected against detection loophole attacks
    • Piotr Mironowicz
    • Gustavo Cañas
    • Jaime Cariñe
    • Esteban S. Gómez
    • Johanna F. Barra
    • Adán Cabello
    • Guilherme B. Xavier
    • Gustavo Lima
    • Marcin Pawłowski
    2021 Quantum Information Processing

    Device and semi-device-independent private quantum randomness generators are crucial for applications requiring private randomness. However, they are vulnerable to detection inefficiency attacks and this limits severely their usage for practical purposes. Here, we present a method for protecting semi-device-independent private quantum randomness generators in prepare-and-measure scenarios against detection inefficiency attacks. The key idea is the introduction of a blocking device that adds failures in the communication between the preparation and measurement devices. We prove that, for any detection efficiency, there is a blocking rate that provides protection against these attacks. We experimentally demonstrate the generation of private randomness using weak coherent states and standard avalanche photo-detectors.

  • QUASI-DISTRIBUTED NETWORK OF LOW-COHERENCE FIBER-OPTIC FABRY-PÉROT SENSORS WITH CAVITY LENGTH-BASED ADDRESSING
    • Katarzyna Karpienko
    • Marcin Marzejon
    • Adam Mazikowski
    • Jerzy Pluciński
    2021 Full text Metrology and Measurement Systems

    Distributed measurement often relies on sensor networks. In this paper, we present the construction of low coherent fiber-optic Fabry-Pérot sensors connected into a quasi-distributed network. We discuss the mechanism of spectrum modulation in this type of sensor and the constraints of assembly of such sensors in the network. Particular attention was paid to separate the signals from individual sensors, which can be achieved by cavity length-based addressing. We designed and built a laboratory model of a temperature sensors network. The employed sensors are lowcoherence Fabry-Pérot interferometric sensors in fiber-optics configuration. The extrinsic sensor cavity utilizes the thermal expansion of ceramics, and the sensors are addressed by the different lengths of the cavities. The obtained test results show that the signal components from each sensor can be successfully separated, and the number of sensors could be expanded depending on the FWHM of the light source

  • Quasistatic and fatigue behavior of an AISI H13 steel obtained by additive manufacturing and conventional method
    • José F. Garcias
    • Rui F. Martins
    • Ricardo Branco
    • Zbigniew Marciniak
    • Wojciech Macek
    • Cândida Pereira
    • Cyril Santos
    2021 Full text FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES

    This work aims to compare the mechanical behavior of an AISI H13 steel obtained by additive manufacturing with that obtained by conventional manufacturing methods. The average values of the ultimate tensile strength (UTS) and ductility obtained for the specimens produced by the conventional method were equal to 658 MPa and 18%, respectively, which compares with 503 MPa and 0.75% registered for the selective laser melting (SLM) specimens. Inversely, the average hardness value determined for the SLM specimens was higher, 450 HV, than the observed for the conventional, 200 HV. In addition, the maximum applied stress corresponding to a fatigue limit's endurance of 2 x 106 cycles was equal to 340 and 85 MPa for conventional and SLM specimens, respectively. Therefore, from a fatigue design point of view, it was possible to infer that σmax/UTS = 0.17 for the SLM specimens tested. Porosity and lack of fusion influenced the static and the fatigue strength negatively in the SLM specimens.

  • Quest for the Molecular Basis of Improved Selective Toxicity of All-Trans Isomers of Aromatic Heptaene Macrolide Antifungal Antibiotics
    • Julia Borzyszkowska-Bukowska
    • Justyna Górska
    • Paweł Szczeblewski
    • Tomasz Laskowski
    • Iwona Gabriel
    • Jakub Jurasz
    • Katarzyna Kozłowska-Tylingo
    • Piotr Szweda
    • Sławomir Milewski
    2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Three aromatic heptaene macrolide antifungal antibiotics, Candicidin D, Partricin A (Gedamycin) and Partricin B (Vacidin) were subjected to controlled cis-trans to all trans photochemical isomerization. The obtained all-trans isomers demonstrated substantially improved in vitro selective toxicity in the Candida albicans cells: human erythrocytes model. This effect was mainly due to the diminished hemotoxicity. The molecular modeling studies on interactions between original antibiotics and their photoisomers with ergosterol and cholesterol revealed some difference in free energy profiles of formation of binary antibiotic/sterol complexes in respective membrane environments. Moreover, different geometries of heptaene: sterol complexes and variations in polyene macrolide molecule alignment in cholesterol- and ergosterol-containing membranes were found. None of these effects are of the crucial importance for the observed improvement of selective toxicity of aromatic heptaene antifungals but each seems to provide a partial contribution.

  • Racjonalność (w) ekonomii. Mapa problemu
    • Andrzej Lisak
    2021

    Praca analizuje racjonalność zjawisk ekonomicznych w perspektywie całości funkcjonowania systemu społecznego, racjonalność podmiotu (homo oeconomicus), racjonalność samych zjawisk ekonomicznych oraz racjonalność ekonomi jako nauki. Stwarza to szerszą filozoficzną perspektywę rozumienia sensu zjawisk ekonomicznych w ludzkim życiu jak i lepsze zrozumienie problemu racjonalności.

  • Radar and Sonar Imaging and Processing (2nd Edition)
    • Andrzej Stateczny
    • Witold Kazimierski
    • Krzysztof Kulpa
    2021 Full text Remote Sensing

    The 14 papers (from 29 submitted) published in the Special Issue “Radar and Sonar Imaging Processing (2nd Edition)” highlight a variety of topics related to remote sensing with radar and sonar sensors. The sequence of articles included in the SI deal with a broad profile of aspects of the use of radar and sonar images in line with the latest scientific trends, in which the latest developments in science, including artificial intelligence, were used.

  • Radiative lifetime of a BODIPY dye as calculated by TDDFT and EOM-CCSD methods: solvent and vibronic effects
    • Rengel Cane Sia
    • Ruben Arturo Arellano-Reyes
    • Tia E. Keyes
    • Julien Guthmuller
    2021 Full text PHYSICAL CHEMISTRY CHEMICAL PHYSICS

    The radiative emission lifetime and associated S1 excited state properties of a BODIPY dye are investigated with TDDFT and EOM-CCSD calculations. The effects of a solvent are described with the polarizable continuum model using the linear response (LR) approach as well as state-specific methods. The Franck–Condon (FC), Herzberg–Teller (HT) and Duschinsky vibronic effects are evaluated for the absorption and emission spectra, and for the radiative lifetime. The transition energies, spectra shapes and radiative lifetime are assessed with respect to experimental results. It is found that the TDDFT transition energies are overestimated by about 0.4–0.5 eV, whereas EOM-CCSD improves the vertical emission energy by about 0.1 eV in comparison to TDDFT. The solvatochromic and Stokes shifts are better reproduced by the state-specific solvation methods, which show that these methods are more suited than the LR model to describe the solvent effects on the BODIPY dye. The vibronic effects lead to an increase of the radiative lifetime of about 0.4 to 1.0 ns depending on the theoretical approach, which highlights the importance of such effects. Moreover, the HT effects are negligible on both the spectra and lifetime, which demonstrates that the FC approximation is accurate for the BODIPY dye. Finally, the comparison with experimental data shows that the radiative lifetimes predicted by EOM-CCSD and TDDFT have comparable accuracy.

  • Rapid determination of multiple aminoglycoside antibiotics in veterinary formulations by ion-pair chromatography coupled with evaporative light scattering detection
    • Marta Glinka
    • Andrzej Wasik
    2021 Full text MICROCHEMICAL JOURNAL

    A fast and simple method for simultaneous determination of eight aminoglycoside antibiotics using ion-pairing liquid chromatography (IPLC) coupled with evaporative light scattering detection (ELSD) has been developed and validated. Separation of amikacin, apramycin, gentamicin (as a sum of gentamicin C1, C2 and C1A), kanamycin A, neomycin B, paromomycin, streptomycin and tobramycin was achieved using C18 column with H2O and MeOH/acetone, both with addition of nonafluoropentanoic acid. Limits of detection ranged between 1.2 μg/mL and 2.8 μg/mL. The total analysis time was 9.5 min. The developed method showed the suitability for the routine quality control of veterinary drugs (drops, powders and paraffin-based suspensions).

  • Rapid development of the photoresponse and oxygen evolution of TiO2 nanotubes sputtered with Cr thin films realized via laser annealing
    • Łukasz Haryński
    • Jakub Karczewski
    • Jacek Ryl
    • Katarzyna Grochowska
    • Katarzyna Siuzdak
    2021 JOURNAL OF ALLOYS AND COMPOUNDS

    Recently, earth abundant transition metal oxides have gained particular attention as potential catalyst candidates due to their availability and low-cost comparing to substrates containing precious Pt or Au species. Herein, we present characterization of morphology, structure and electrochemical properties of pulsed 532 nm laser treated TiO2 nanotubes (NT) sputtered by the thin film of chromium. Scanning electron microscopy enables verification of the diameter and length of titania while Raman and X-ray photoelectron spectroscopies were used to evaluate crystalline phase and the oxidation state of elements, respectively. The recorded polarization curves clearly indicate that the optimized laser-treatment enhances activity towards oxygen evolution reaction (OER) of the TiO2 NT decorated with very small amount of Cr species. The analysis of Mott-Schottky plot shows significant increment in donor density (Nd) for the laser irradiated sample comparing to the one before annealing and pristine titania resulting from the effective manipulation of the electrode/electrolyte interface. Moreover, the impact of the processing parameters including energy fluence of laser beam and the thickness of sputtered Cr layer on the current density was evaluated by the electrochemical measurements performed under vis and UV–vis light. The results show promising application of direct interaction of laser beam with the surface of material exhibiting initially both poor OER activity and visible light response.

  • Rapid Multi-Criterial Antenna Optimization by Means of Pareto Front Triangulation and Interpolative Design Predictors
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2021 Full text IEEE Access

    Modern antenna systems are designed to meet stringent performance requirements pertinent to both their electrical and field properties. The objectives typically stay in conflict with each other. As the simultaneous improvement of all performance parameters is rarely possible, compromise solutions have to be sought. The most comprehensive information about available design trade-offs can be obtained through multi-objective optimization (MO), typically in the form of a Pareto set. Notwithstanding, MO is a numerically challenging task, in a large part due to high CPU cost of evaluating the antenna properties, normally carried out through full-wave electromagnetic (EM) analysis. Surrogate-assisted procedures can mitigate the cost issue to a certain extent but construction of reliable metamodels is hindered by the curse of dimensionality, and often highly nonlinear antenna characteristics. This work proposes an alternative approach to MO of antennas. The major contribution of our work consists in establishing a deterministic machine learning procedure, which involves sequential generation of Pareto-optimal designs based on the knowledge gathered so far in the process (specifically, by triangulation of the already obtained Pareto set), and local surrogate-assisted refinement procedures. Our methodology allows for rendering uniformly-distributed Pareto designs at the cost of a few hundreds of antenna EM simulations, as demonstrated by means of three verification case studies. Benchmarking against state-of-the-art MO techniques is provided as well.

  • Reactivity of bulky aminophosphanes towards small molecules: Activation of dihydrogen and carbon dioxide by aminophosphane/borane frustrated Lewis pairs
    • Magdalena Siedzielnik
    • Kinga Kaniewska-Laskowska
    • Natalia Szynkiewicz
    • Jarosław Chojnacki
    • Rafał Grubba
    2021 POLYHEDRON

    A series of mono- and bisaminophosphanes with formulas R<sub>2</sub>NPR’R’’ and (R<sub>2</sub>N)<sub>2</sub>PR’ (R = iPr, Cy; R’ = Ph, Cy; R’’ = iPr) were characterized by X-ray analysis, NMR spectroscopy and computational methods. The common structural futures of these species are short and polarized PAN bonds, a pyramidal geometry at the P atom and an almost planar geometry at the N atoms. According to DFT calculations, these compounds are highly nucleophilic, with nucleophilic centers located on the N and P atoms. Except for species containing a PPh<sub>2</sub> moiety, the obtained aminophosphanes are air-stable and do not react with water. They form stable frustrated Lewis pairs with BPh3 or B(C6F5)3. Mono- and bisaminophosphanes in the presence of B(C6F5)3 activate dihydrogen and carbon dioxide at room temperature

  • Real-time isothermal DNA amplification monitoring in picoliter volumes using an optical fiber sensor
    • Monika Janik
    • Seyed Vahid Hamidi
    • Marcin Koba
    • Jonathan Perreault
    • Ryan Walsh
    • Wojtek J. Bock
    • Mateusz Śmietana
    2021 LAB ON A CHIP

    Rolling circle amplification (RCA) of DNA can be considered as a great alternative to the gold standard polymerase chain reaction (PCR), especially during this pandemic period, where rapid, sensitive, and reliable test results for hundreds of thousands of samples are required daily. This work presents the first research to date on direct, real-time and label-free isothermal DNA amplification monitoring using a microcavity in-line Mach–Zehnder interferometer (μIMZI) fabricated in an optical fiber. The solution based on μIMZI offers a great advantage over many other sensing concepts – making possible optical analysis in just picoliter sample volumes. The selectivity of the biosensor is determined by DNA primers immobilized on the microcavity's surface that act as selective biorecognition elements and trigger initiation of the DNA amplification process. In this study, we verified the sensing concept using circular DNA designed to target the H5N1 influenza virus. The developed biosensor exhibits an ultrahigh refractive index sensitivity reaching 14 000 nm per refractive index unit and a linear detection range between 9.4 aM and 94 pM of the target DNA sequence. Within a 30 min period, the amplification of as little as 9.4 aM DNA can be effectively detected, with a calculated limit of detection of as low as 0.2 aM DNA, suggesting that this methodology holds great promise in practical disease diagnosis applications in the future.

  • Real-time monitoring of volatiles and particles emitted from thermoplastic filaments during 3D printing
    • Wojciech Wojnowski
    2021

    Presentation on the use of instrumental analytical techniques for the assessment of emission of volatiles and particulates during fdm 3d printing.

  • Real-time monitoring of volatiles and particles emitted from thermoplastic filaments during 3D printing
    • Wojciech Wojnowski
    • Renata Marcinkowska
    • Bożena Zabiegała
    2021 Full text IOP Conference Series: Materials Science and Engineering

    The proliferation of consumer-grade three-dimensional (3D) printers using fused deposition, also known as fused filament fabrication, has given rise to concerns over the exposure of users to potentially harmful substances. Thermoplastic filaments made of different polymers are extruded through a heated printer nozzle and deposited layer by layer on a build platform to form the printed object. This process leads to the emission of both particles and gases, in particular volatile organic compounds (VOCs). While the emission of airborne particulate matter during 3D-printing has been relatively well researched [1], this is not the case with the monitoring of the associated emission of VOCs, and so we are far from understanding the emission profile of 3D-printers as a whole. The main reason for that is the difficulty with sampling the emitted volatiles with sufficient time resolution to investigate e.g. the effect of rapid heating of the nozzle, and so the available data mostly describes either the total emission of particular VOCs during printing, or the time-resolved emission of total VOCs, without the determination of particular compounds [2,3]. In order to bridge this gap, we have previously demonstrated that proton transfer reaction mass spectrometry (PTR-MS) can be used to monitor the emission of volatiles during 3D-printing in real-time, both qualitatively and quantitatively [4]. Here, we propose to combine this approach with the concurrent real-time measurement of the corresponding emission of particles to obtain a more detailed understanding of the profile of pollutants generated during 3D-printing and the factors which determine this process.

  • Recent Advances in Accelerated Multi-Objective Design of High-Frequency Structures using Knowledge-Based Constrained Modeling Approach
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2021 KNOWLEDGE-BASED SYSTEMS

    Design automation, including reliable optimization of engineering systems, is of paramount importance for both academia and industry. This includes the design of high-frequency structures (antennas, microwave circuits, integrated photonic components), where the appropriate adjustment of geometry and material parameters is crucial to meet stringent performance requirements dictated by practical applications. Realistic design has to account for multiple objectives, which are often conflicting. Identification of available trade-offs (e.g., electrical/field properties vs. physical size and cost), otherwise essential from industry standpoint, requires multi-objective optimization. It is a computationally expensive endeavor as in most cases—for the sake of accuracy—the system evaluation has to be carried out using full-wave electromagnetic (EM) analysis. Attempting to solve EM-driven multi-objective (MO) tasks directly using population-based nature-inspired techniques may be prohibitive in terms of cost. Employing surrogate modeling techniques can lead to mitigation of the cost issue; however, construction of fast replacement models over broad ranges of the system parameters is expensive by itself, especially in higher-dimensional spaces. Recently, several approaches involving knowledge-based surrogate modeling approach have been proposed with the metamodels constructed over small regions of the parameter space containing the Pareto front. The latter are approximated using the sets of pre-optimized reference designs and permit a dramatic reduction of the number of training points required to set up a reliable surrogate, thus reducing the overall cost of the MO process. This paper reviews the recent advancements in these methodologies, and demonstrates the benefits of domain confinement using the various techniques such as reference design triangulation, nested kriging, and modeling with explicit dimensionality reduction using spectral analysis of the reference set. Demonstration examples of multi-objective design of antenna and miniaturized microwave components are provided as well.

  • Recent Advances in Loop Heat Pipes with Flat Evaporator
    • Paweł Szymański
    • Richard Law
    • Ryan McGlen
    • David Reay
    2021 Full text ENTROPY

    The focus of this review is to present the current advances in Loop Heat Pipes (LHP) with flat evaporators, which address the current challenges to the wide implementation of the technology. A recent advance in LHP is the design of flat-shaped evaporators, which is better suited to the geometry of discretely mounted electronics components (microprocessors) and therefore negate the need for an additional transfer surface (saddle) between component and evaporator. However, various challenges exist in the implementation of flat-evaporator, including (1) deformation of the evaporator due to high internal pressure and uneven stress distribution in the non-circular casing; (2) heat leak from evaporator heating zone and sidewall into the compensation chamber; (3) poor performance at start-up; (4) reverse flow through the wick; or (5) difficulties in sealing, and hence frequent leakage. This paper presents and reviews state-of-the-art LHP technologies; this includes an (a) review of novel manufacturing methods; (b) LHP evaporator designs; (c) working fluids; and (d) construction materials. The work presents solutions that are used to develop or improve the LHP construction, overall thermal performance, heat transfer distance, start-up time (especially at low heat loads), manufacturing cost, weight, possibilities of miniaturization and how they affect the solution on the above-presented problems and challenges in flat shape LHP development to take advantage in the passive cooling systems for electronic devices in multiple applications.

  • Recent advances on spinel-based protective coatings for solid oxide cell metallic interconnects produced by electrophoretic deposition
    • E Zanchi
    • A Sabato
    • Sebastian Molin
    • Grzegorz Cempura
    • A Boccaccini
    • F Smeacetto
    2021 MATERIALS LETTERS

    The application of ceramic protective coatings to the metallic interconnects in solid oxide cells (SOCs) is a viable and effective method to limit interconnect degradation issues. This featured letter provides a critical overview of the main outcomes of current research on the use of the electrophoretic deposition (EPD) technique to produce protective coatings for SOC metallic interconnects, specifically focusing on different approaches to stabilise spinel-based suspensions, as well as the possible sintering procedures. The protective properties of EPD coatings are reviewed and discussed in terms of oxidation kinetics and area specific resistance evaluation.

  • Recent advances on the removal of phosphorus in aquatic plant-based systems
    • Shahabaldin Rezania
    • Hesam Kamyab
    • Parveen Fatemeh Rupani
    • Junboum Park
    • Nicole Nawrot
    • Ewa Wojciechowska
    • Krishna Kumar Yadav
    • Majid Lotfi Ghahroud
    • Ali Akbar Mohammadi
    • Sathiabama T. Thirugnana
    • Shreeshivadasan Chelliapan
    • Marina M.S. Cabral-Pinto
    2021 Environmental Technology & Innovation

    Phosphorus (P) is a vital nutrient for the ecosystems and its excess in wastewater streams leads to some environmental issues such as extensive algae growth (eutrophication). Phytoremediation is a green technology that is based on the combined actions of plants and their associated microbial groups to remove and transfer the toxic compounds in surface water, groundwater and soil. Aquatic plants are widely used for the remediation of contaminated rivers, eutrophic lakes, and other water bodies. In the past three decades, free-floating, submerged, emergent macrophytes and microalgae species have been used for P removal in aquatic plant-based systems such as constructed wetlands (CWs). This paper reviews the recent studies on the potential of aquatic plants such as free-floating, submerged, and emergent plants, and also microalgae for removal of P in different types of wastewaters. Several parameters such as plant species, hydraulic retention time, temperature, type of CWs, effluent concentration, and seasonal changes have effects on P removal. Based on the findings, some of the species such as Azolla and water hyacinth had the highest uptake ability up to 90% while algae species such as Chlorella showed about 70% of P removal. In addition, the mixed culture of aquatic plants can increase P removal if the interaction of the species is considered before cultivation in CWs.

  • Recent Applications of 1D GC-MS and 2D GC-MS in Foodomics Studies
    • Tomasz Majchrzak
    • Kaja Kalinowska
    • Martyna Lubinska-Szczygeł
    • Anna Różańska
    • Tomasz Dymerski
    • Waldemar Wardencki
    • Jacek Namieśnik
    2021

    Gas chromatography coupled with mass spectrometry and food chemistry have been tightly linked since the 1960s. This setup is also an integral part of the omics studies when it comes to low mass metabolites. Therefore, the marriage of GC-MS and foodomics is obvious. Two-dimensional gas chromatography coupled with mass spectrometry fits perfectly within the latest trends in foodomics, since it is tailored for holistic food analysis. In this article, the authors will focus on the current trends in 1D and 2D GC-MS-based foodomics.

  • Recent Developments in Data-Assisted Modeling of Flexible Proteins
    • Cezary Czaplewski
    • Zhou Gong
    • Emilia Lubecka
    • Kai Xue
    • Chun Tang
    • Adam Liwo
    2021 Full text Frontiers in Molecular Biosciences

    Many proteins can fold into well-defined conformations. However, intrinsically-disordered proteins (IDPs) do not possess a defined structure. Moreover, folded multi-domain proteins often digress into alternative conformations. Collectively, the conformational dynamics enables these proteins to fulfill specific functions. Thus, most experimental observables are averaged over the conformations that constitute an ensemble. In this article, we review the recent developments in the concept and methods for the determination of the dynamic structures of flexible peptides and proteins. In particular, we describe ways to extract information from nuclear magnetic resonance small-angle X-ray scattering (SAXS), and chemical cross-linking coupled with mass spectroscopy (XL-MS) measurements. All these techniques can be used to obtain ensemble-averaged restraints or to re-weight the simulated conformational ensembles.

  • Recovering Evaluation of Narrow-Kerf Teeth of Mini Sash Gang Saws
    • Kazimierz Orłowski
    • Daniel Chuchała
    • Tomasz Przybyliński
    • Stanisław Legutko
    2021 Full text Materials

    Sash gang saws with narrow-kerf saw blades are used in the production of glued laminate flooring elements in plants where dry technology is applied. This means that boards or friezes are sawn into top layer lamellae in dry conditions (moisture content of about 10–12%) from expensive wood species, often exotic. The object of this research was stellite-tipped teeth of narrow kerf saw blades sharpened under industrial conditions. A NIKON ECLIPSE Ti-S microscope equipped with a NIKON DS-Fi2 recording camera was used to take pictures of teeth, which were analysed in a graphical software to measure the radii of the main cutting edges. The high-quality images obtained were used to determine the values of the rounding radii of the cutting edges. It was noted that the quality of edges regenerated in industrial conditions, some of which had chipping, was lower than that of brand new saw blades.

  • Recovery of Valuable Materials and Methods for Their Management When Recycling Thin-Film CdTe Photovoltaic Modules
    • Anna Kuczyńska-Łażewska
    • Ewa Klugmann-Radziemska
    • Agnieszka Witkowska
    2021 Full text Materials

    Due to the development of new photovoltaic technologies, there is a need to research new recycling methods for these new materials. The recovery of metals from photovoltaic (PV) modules would reduce the consumption of raw materials. Therefore, the development of recycling technologies for used and damaged modules of newer generations is important for environmental reasons. The aim of the research is to shed light on the nature of the chemical reactions that occur in recycling technology for second-generation photovoltaic modules. This work is focused mainly on cells made of Cadmium Telluride (CdTe). It was proven that prior thermal delamination was necessary. Moreover, an improvement in understanding of the recovery process depending on used leaching solution was achieved.

  • Recycling of Polyurethanes Containing Flame-Retardants and Polymer Waste Transformed into Flame-Retarded Polyurethanes
    • Marcin Włoch
    2021

    The growing number of polyurethanes (PUs) produced every year has developed methods for their mechanical and chemical recycling which yield valuable products like substitutes for commercial polyols or flame-retardants. PUs can be produced in different shapes and forms (i.e., elastomers, flexible or rigid foams, coatings, etc.) using several different components (i.e., di- or polyisocyanates, ester- or ether-based polyols, low-molecular weight chain extenders, fillers, and other modifiers). Therefore, different recycling methods should be considered for a wide range of materials, including postproduction of postconsumer wastes) depending on their chemical structure and properties. This chapter presents a review of selected mechanical (e.g., regrinding and using as a filler, rebonding, and compression molding) and chemical (e.g., glycolysis, glycerolysis, acidolysis and phosphorolysis) recycling methods applicable for PUs. This chapter also presents examples of flame-retardants and flame-retarded PUs obtained by PU recycling, poly(ethylene terephthalate), and melamine formaldehyde foam.

  • Recycling of Waste Rubber by the Manufacturing of Foamed Polyurethane-Based Composites—Current State and Perspectives
    • Aleksander Hejna
    • Krzysztof Formela
    • Łukasz Zedler
    • Paulina Kosmela
    • Adam Olszewski
    2021 Full text Proceedings

    Worn car tires are disruptive waste, and the issue of their management is crucial for the natural environment. In many countries, the primary method of end-of-life tires utilization is energy recovery. However, more effective and beneficial for the environment is material recycling. Using them for the production of polymer-rubber composites seems to be an auspicious direction of research. Incorporation of ground tire rubber into polyurethane matrix should be considered as a method of waste rubber utilization. Moreover, it could significantly reduce the use of petroleum-based polyols and isocyanates, which are commonly considered as toxic chemicals. Therefore, the total impact on the environment could be noticeably reduced, which should be considered as very beneficial step towards more “green” polymer composites. This work aims to summarize the literature reports related to the foamed polyurethane/ground tire rubber composites. It particularly emphasizes the need for compatibilization of these materials by the enhancement of interfacial interactions between the polyurethane matrix and rubber filler phase, which significantly affect the performance properties of prepared materials. As an example, we presented our research results. Besides, future trends and limitations related to this type of composite materials are underlined.

  • Recycling of Waste Rubber by Thermo-Mechanical Treatment in a Twin-Screw Extruder
    • Łukasz Zedler
    • Paulina Kosmela
    • Adam Olszewski
    • Paulina Burger
    • Krzysztof Formela
    • Aleksander Hejna
    2021 Full text Proceedings

    Recycling of waste tires is a significant issue considering both environmental and economic aspects. One of the leading recycling routes is the shredding of tires resulting in the generation of ground tire rubber. This material can be easily introduced into various polymer matrices as a filler, reducing the use of conventionally applied petroleum-based materials. In such cases, it is essential to ensure sufficient interfacial compatibility, which could be achieved by the proper modification of the rubber surface. Different methods of treatment of ground tire rubber aim to activate its surface and introduce functional groups, which could provide the possibility for interfacial interactions and incorporation of the significant amounts of recycled material. Therefore, in the presented paper, we examined the impact of thermo-mechanical treatment in twin-screw extruder on the appearance and chemical structure of ground tire rubber. Moreover, for each set of process parameters, the specific mechanical energy required for the processing was calculated, which could provide essential insights for the potential industrial application of the analyzed process. The energy demand should be considered as a very important issue during development of “greener” processes and materials.

  • Redox property switching in MOFs with open metal sites for improved catalytic hydrogenation performance
    • Longlong Geng
    • Wenfeng Zhou
    • Xiaoli Wang
    • Tingting Li
    • Andrzej Nowak
    • Zhongmin Liu
    • Yong-Zheng Zhang
    • Da-Shuai Zhang
    • Xiuling Zhang
    • Haixiang Han
    2021 JOURNAL OF ALLOYS AND COMPOUNDS

    In this study, a decompression-thermalization strategy was utilized for a Cu-containing metal-organic framework (MOF) to tune its redox and catalytic hydrogenation properties. Remarkably, at just 120 °C, open metal sites (OMSs) were successfully constructed by removing coordinated solvent molecules to generate the daughter MOF-120. The tailored redox property of MOF-120 is correlated with the presence of OMSs. Compared with the pristine MOF where copper cations were capped by DMF, MOF-120 exhibited improved kinetics, showed a reduction of activation energy and outstanding recyclability in the hydrogenation of 4-nitrophenol under mild conditions (25 °C, 1 atm). Both experimental studies and theoretical calculation results reveal that the generation of OMSs endows the Cu species with unique electronic properties, which assist the adsorption and electron transfer between substrate molecules and is responsible for the enhanced performance in the hydrogenation process.

  • Reduced-Cost Microwave Design Closure by Multi-Resolution EM Simulations and Knowledge-Based Model Management
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Piotr Płotka
    2021 Full text IEEE Access

    Parameter adjustment through numerical optimization has become a commonplace of contemporary microwave engineering. Although circuit theory methods are ubiquitous in the development of microwave components, the initial designs obtained with such tools have to be further tuned to improve the system performance. This is particularly pertinent to miniaturized structures, where the cross-coupling effects cannot be adequately accounted for using equivalent networks. For the sake of reliability, design closure is normally performed using full-wave electromagnetic (EM) simulation models, which entails considerable computational expenses, often impractically excessive. Available mitigation techniques include acceleration of the conventional (e.g., gradient-based) routines using adjoint sensitivities or sparse sensitivity updates, surrogate-assisted and machine learning algorithms, the latter often combined with nature-inspired procedures. Another alternative is the employment of variable-fidelity simulations (e.g., space mapping, co-kriging), which is most often limited to two levels of accuracy (coarse/fine). This work discusses an EM model management approach coupled with trust-region gradient-based routine, which exploits problem-specific knowledge for continuous (multi-level) modification of the discretization density of the microwave structure at hand in the course of the optimization run. The optimization process is launched at the lowest discretization level, thereby allowing for low-cost exploitation of the knowledge about the device under study. Subsequently, based on the convergence indicators, the model fidelity is gradually increased to ensure reliability. The simulation fidelity selection is governed by the algorithm convergence indicators. Computational speedup is achieved by maintaining low resolution in the initial stages of the optimization run, whereas design quality is secured by eventually switching to the high-fidelity model when close to concluding the process. Numerical verification is carried out using two microstrip circuits, a dual-band power divider and a dual-band branch-line coupler, with the average savings of almost sixty percent when compared to single-fidelity optimization.

  • Regularized identification of fast time-varying systems - comparison of two regularization strategies
    • Artur Gańcza
    • Maciej Niedźwiecki
    2021 Full text

    The problem of identification of a time-varying FIR system is considered and solved using the local basis function approach. It is shown that the estimation (tracking) results can be improved by means of regularization. Two variants of regularization are proposed and compared: the classical L2 (ridge) regularization and a new, reweighted L2 one. It is shown that the new approach can outperform the classical one and is computationally attractive.

  • Regularized Identification of Time-Varying FIR Systems Based on Generalized Cross-Validation
    • Artur Gańcza
    • Maciej Niedźwiecki
    2021 Full text

    A new regularization method is proposed and applied to identification of time-varying finite impulse response systems. We show, that by a careful design of the regularization constraint, one can improve estimation results, especially in the presence of strong measurement noise. We also show that the the most appropriate regularization gain can be found by direct optimization of the generalized cross-validation criterion.

  • Regularized Local Basis Function Approach to Identification of Nonstationary Processes
    • Artur Gańcza
    • Maciej Niedźwiecki
    • Marcin Ciołek
    2021 Full text IEEE TRANSACTIONS ON SIGNAL PROCESSING

    The problem of identification of nonstationary stochastic processes (systems or signals) is considered and a new class of identification algorithms, combining the basis functions approach with local estimation technique, is described. Unlike the classical basis function estimation schemes, the proposed regularized local basis function estimators are not used to obtain interval approximations of the parameter trajectory, but provide a sequence of point estimates corresponding to consecutive instants of time. Based on the results of theoretical analysis, the paper addresses and solves all major problems associated with implementation of the new class of estimators, such as optimization of the regularization matrix, adaptive selection of the number of basis functions and the width of the local analysis interval, and reduction of complexity of the computational algorithms.

  • Reinforcement Learning Algorithm and FDTD-based Simulation Applied to Schroeder Diffuser Design Optimization
    • Adam Kurowski
    • Bożena Kostek
    2021 Full text IEEE Access

    The aim of this paper is to propose a novel approach to the algorithmic design of Schroeder acoustic diffusers employing a deep learning optimization algorithm and a fitness function based on a computer simulation of the propagation of acoustic waves. The deep learning method employed for the research is a deep policy gradient algorithm. It is used as a tool for carrying out a sequential optimization process the goal of which is to maximize the fitness function based on parameters characterizing the autocorrelation diffusion coefficient of the designed acoustic diffuser. As the autocorrelation acoustic diffusion coefficients are calculated from the polar response of a diffuser, the FDTD (finite-difference time-domain) simulation method is used to obtain a set of impulse responses necessary to calculate the polar responses of the optimized Schroeder diffusers. The results obtained from optimization based on the deep learning algorithm were compared with the outcomes of an analogous algorithm employing a genetic algorithm, and based on random selection of the Schroeder diffuser well depth pattern. We found that the best result was achieved by the deep policy gradient, as it produced outcomes, which, in terms of the provided autocorrelation diffusion coefficient, were statistically better than properties of designs provided by two other baseline approaches.

  • Relacja mistrz – uczeń – w jaki sposób kształtować doskonałość akademicką, na przykładzie postaci prof. dr. hab. inż. Romualda Kolmana
    • Piotr Grudowski
    • Małgorzata Wiśniewska
    2021 Problemy Jakości

    W niniejszym artykule skoncentrowano się na zagadnieniu fundamentalnym w kontekście edukacji i rozwoju badań naukowych – relacji mistrz – uczeń. W nawiązaniu do wielowiekowej tradycji instytucji akademickich przedstawiono istotę i znaczenie tych relacji, wskazując pożądane cechy mistrza jako osoby kształtującej oczekiwane ze względów społecznych postawy swoich podopiecznych. Jako przykład postaci mistrza w obszarze nauk o jakości zaprezentowano sylwetkę śp. Profesora Romualda Kolmana oraz wspomnienia niektórych z jego wychowanków. W nawiązaniu do obecnej sytuacji w systemie szkolnictwa wyższego i nauki w Polsce autorzy pragną w ten sposób zwrócić uwagę na – ich zdaniem – zdecydowanie niewystarczające, a wręcz pomijane w różnego rodzaju regulacjach, wsparcie tej sfery aktywności akademickiej

  • Relating Information Culture to Information Policies and Management Strategies
    • Denise A. D. Bedford
    • Wioleta Kucharska
    2021

    Business and information managers have struggled to meet several challenges in aligning information strategies and business cultures. The consequences of a misalignment or misfit of strategy and culture are well known in business literature, and better guidance on how to better align strategy and culture is needed. This means expanding the puzzle to align business and information cultures, align business and information strategies, and ensuring that there is a good ongoing fit between information cultures and business strategies. It also means that awareness of the information capabilities of an organization needs to be raised along with the different levels and types of information cultures. Relating Information Culture to Information Policies and Management Strategies is a critical scholarly publication that provides a holistic picture of information cultures in order to help business managers understand those cultures and to provide a foundation upon which to ground and grow future information culture research. Highlighting a wide range of topics such as information culture, business strategies, and risk assessment, this book is essential for business managers, organizational executives, information managers, cultural experts, practitioners, academicians, managers, researchers, and students.

  • Relationships Between Geographical and Virtual Proximity in Cluster Organisations
    • Anna Lis
    • Adrian Lis
    2021 Full text Studia Regionalne i Lokalne

    The purpose of the paper is to explore the relationships between geographical and virtual proximity in cluster organizations (COs). The authors report the findings of a qualitative study conducted in four COs in Poland. The basic technique for collecting and analyzing data was an in-depth individual interview and qualitative content analysis. The research has shown that the relationships between geographical and virtual proximity depends on the cooperation level and the role of the CO. The findings presents a broader view on cluster cooperation as a phenomenon based in geographical proximity which facilitates personal interactions, but supported by various ICT tools.

  • Relative Productivity, Country Size and Export Diversification
    • Andrzej Cieślik
    • Aleksandra Parteka
    2021 Full text Structural Change and Economic Dynamics

    This paper analyses the effects of productivity and country size on the extent of trade structure diversification. Using a testable version of the Ricardian model, we show that relative export variety is an outcome of two forces: a relative productivity change (technological progress) and a relative country size change (labour force growth). The model predictions are validated empirically using product-level trade data for a sample of 132 countries (1988–2014), including 53 low-income countries. We find a robust positive relationship between export variety and the countries’ relative productivity, as well as a negative relationship between export variety and the expansion of foreign economies (i.e., the growth of the RoW). The effect of technology differences on export variety is driving diversification especially at the beginning of the development process. The results are robust to changes in the measurement of export variety (also in terms of economic complexity), in the set of control variables, or in the estimation methods.

  • Relay-aided Wireless Sensor Network Discovery Algorithm for Dense Industrial IoT utilizing ESPAR Antennas
    • Fjolla Ademaj
    • Mateusz Rzymowski
    • Hans-Peter Bernhard
    • Krzysztof Nyka
    • Łukasz Kulas
    2021 Full text IEEE Internet of Things Journal

    Industrial Internet of Things (IIoT) applicationsrequire reliable and efficient wireless communication. Assumingdense Wireless Sensor Networks (WSNs) operating in a harshenvironment, a concept of a Time Division Multiple Access(TDMA) based WSN enriched with Electronically SteerableParasitic Array Radiator (ESPAR) antennas is proposed andexamined in this work. The utilized antenna provides oneomnidirectional and 12 directional radiation patterns that can beelectronically switched by the sensor node. We introduce a relaydiscovery algorithm which selects those sensor nodes with anESPAR antenna capable to act as relay. The selection of the relaynodes is based on a certain link quality threshold that algorithmuses as input. The outcome is a reduction in number of layers orhops with a guaranteed Quality of Service (QoS). To emphasizethe physical aspect of the wireless propagation, we introduce themeasured antenna radiation patterns and consider two differentpath loss propagation models representing blockage-free andblockage-prone industrial environments. A number of networksimulations were performed and Signal-to-Noise Ratio (SNR) as alink quality measure was examined with respect to the networkdensity and different measured radiation pattern settings. Themain outcomes show a trade-off between SNR per link and thepercentage of nodes that can serve as relays. As a result, wepropose network design guidelines that take under considerationthe QoS range with respect to SNR together with an optimalnumber of antenna radiation patterns that should be selected asa trade-off between latency, energy consumption and reliabilityin a network

  • Release Kinetics Studies of Early-Stage Volatile Secondary Oxidation Products of Rapeseed Oil Emitted during the Deep-Frying Process
    • Tomasz Majchrzak
    • Andrzej Wasik
    2021 Full text MOLECULES

    The research concerns the use of proton transfer reaction mass spectrometer to track real-time emissions of volatile secondary oxidation products released from rapeseed oil as a result of deep-frying of potato cubes. Therefore, it was possible to observe a sudden increase of volatile organic compound (VOC) emissions caused by immersion of the food, accompanied by a sudden release of steam from a potato cube and a decrease of the oil temperature by more than 20 °C. It was possible to identify and monitor the emission of major secondary oxidation products such as saturated and unsaturated aldehydes, namely acrolein, pentanal, 2-hexenal, hexanal, 2-nonenal and 2-decenal. Each of them has an individual release characteristic. Moreover, the impact of different initial frying temperatures on release kinetics was investigated. Subsequently, it was possible to approximate the cumulative emission by a second-degree polynomial (R2 ≥ 0.994). Using the proposed solution made it possible for the first time to observe the impact of the immersion of food in vegetable oil on the early emission of thermal degradation products oil.

  • Remarkable visible-light induced hydrogen generation with ZnIn2S4 microspheres/CuInS2 quantum dots photocatalytic system
    • Onur Cavdar
    • Anna Malankowska
    • Daniel Amgar
    • Paweł Mazierski
    • Justyna Łuczak
    • Wojciech Lisowski
    • Adriana Zaleska-Medynska
    2021 Full text INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    A new and active material in the form of ZnIn2S4 microspheres decorated by CuInS2 quantum dots have been obtained by hydrothermal method for the first time. The optimum amount of CuInS2 quantum dots (1.13 wt.%) introduced into rection medium during ZnIn2S4 microspheres synthesis increased the photocatalytic H2 generation rate by 2.5 times than that of bare ZnIn2S4 photocatalysis under visible light irradiation. This sample exhibited strong photoactivity in the extended visible range up to 540 nm with 30.6% apparent quantum efficiency (λ = 420 nm).

  • Remote command and control capabilities for data acquisition systems provided by delay-tolerant network mechanisms
    • Michał Hoeft
    • Krzysztof Gierłowski
    • Marcin Wichorowski
    2021 Bollettino di Geofisica Teorica ed Applicata

    The paper presents an assessment of a remote device reconfiguration service employing a Delay Tolerant Network (DTN) mechanisms. This service has been implemented as a part of a communication appliance dedicated to marine data transfer in off-shore and open sea areas. The service has been successfully deployed and validation test have been completed. The practical use-case has been defined as remote access to the equipment operating onboard RV “Oceania” during cruise on Southern Baltic Area. A summary of service characteristics is included, as well as simulation results of large scale deployment of the system in the south and central areas of Baltic Sea.

  • Remote communication in Scrum teams - a COVID-19 preventive measure or work time optimisation?
    • Kamil Brodnicki
    2021 Full text e-mentor

    The article presents the impact of remote work, resulting from the COVID-19 pandemic, on the functioning of Scrum teams. Attempts have been made to analyse the positive and negative aspects of remote work. The article also looks at the impact of remote work on the level of communication and efficiency of Scrum teams. For this purpose, the author conducted research on a sample of 40 organisations that declared to use Scrum methodology, using 187 questionnaires as the research material. The study was carried out at the turn of April and May 2021 and was carried out using the CAWI technique. The obtained results were analysed using the Principal Component Analysis and Cluster Analysis methods, and enable defining a picture of an organisation's readiness to work remotely. In addition, they also allowed for an assessment of how the infrastructure used for remote work communication translates into the organisation of Sprint meetings. This paper presents conclusions aimed at counteracting the observed irregularities detected during the tests. At the end, the author proposes solutions that could improve communication within Scrum teams, with remote work in mind.

  • Remote measurement of building usable floor area - Algorithms fusion
    • Artur Janowski
    • Małgorzata Renigier-Biłozor
    • Marek Walacik
    • Aneta Chmielewska
    2021 LAND USE POLICY

    Rapid changes that are taking place in the urban environment have significant impact on urban growth. Most cities and urban regions all over the world compete to increase resident and visitor satisfaction. The growing requirements and rapidity of introducing new technologies to all aspects of residents' lives force cities and urban regions to implement "smart cities" concepts in their activities. Real estate is one of the principal anthropogenic components of urban environment thus become a subject of thorough multidisciplinary analysis in the field of data requiring spatial information systems. Recent advances in information technology, combined with the increased availability of high-resolution imagery from Earth observation, create an opportunity to use new sources of data that enable to identify, monitor, and solved many of urban environmental problem. The aim of the paper is to elaborate precise, complete and detailed property information with the use of remote sensing observations in a suitable numerical algorithm. The authors concentrate on providing one of the most important, and probably the most lacking, feature describing properties - building usable floor area (BUFA). The solution is elaborated in the form of an automatic algorithm based on machine learning and computer vision technology related to LiDAR (big data), close range images with respect to spatial information systems requirements. The obtained results related to BUFA estimation in comparison to the state-of-the-art results are satisfactory and may increase the reliability of decision-making in investment, fiscal, registration and planning aspects.