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Gdańsk University of Technology

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  • Social benefits valuation of hosting non-mega sporting events
    • Krystian Zawadzki
    2020 Full text International Journal of Event and Festival Management

    Purpose In the study, an attempt was made to estimate the social benefits resulting from three non-mega sporting events organized in Ergo Arena located on the border of two cities in Poland. By attributing a value to intangible social benefits, the intangible effect was determined and compared to the expenditure incurred in the construction of Ergo Arena Hall. Design/methodology/approach In order to value social intangible effects of three non-mega sporting events the Contingent Valuation Method was applied. Each time, the Contingent Valuation Method study covered the area of the two cities: Gdańsk and Sopot and was conducted on a sample of 500 people – 250 per city. The mean values of Willingness-to-Pay were used in order to obtain aggregate values of intangible benefits. Finally, the aggregate results were compared to expenditure incurred in connection with the construction of Ergo Arena Hall. Findings It appeared that intangible effects were eagerly valued by the residents of Gdańsk and Sopot. The aggregated value of all three sporting events was estimated at PLN 8.8 million. The obtained results question the equal share of both cities in financing but confirm that under certain circumstances, hosting non-mega sporting events may justify the use of public funds. In the case of the two cities, the reasonable reason for the employment of public means is the size of Gdańsk compared to Sopot. Originality/value The paper fulfils the research gap which arises regarding Willingness-to-Pay in estimating the intangible social effects of non-mega sporting events and considering these effects in the net effect valuation. The findings have implications for policy makers since they show to what extent it may be justified to use public means in order to host non-mega sporting events.

  • Soft Sensor Application in Identification of the Activated Sludge Bulking Considering the Technological and Economical Aspects of Smart Systems Functioning
    • Bartosz Szeląg
    • Jakub Drewnowski
    • Grzegorz Łagód
    • Dariusz Majerek
    • Ewa Dacewicz
    • Francesco Fatone
    2020 Full text SENSORS

    The paper presented the methodology for the construction of a soft sensor used for activated sludge bulking identification. Devising such solutions fits within the current trends and development of a smart system and infrastructure within smart cities. In order to optimize the selection of the data-mining method depending on the data collected within a wastewater treatment plant (WWTP), a number of methods were considered, including: artificial neural networks, support vector machines, random forests, boosted trees, and logistic regression. The analysis conducted sought the combinations of independent variables for which the devised soft sensor is characterized with high accuracy and at a relatively low cost of determination. With the measurement results pertaining to the quantity and quality of wastewater as well as the temperature in the activated sludge chambers, a good fit can be achieved with the boosted trees method. In order to simplify the selection of an optimal method for the identification of activated sludge bulking depending on the model requirements and the data collected within the WWTP, an original system of weight estimation was proposed, enabling a reduction in the number of independent variables in a model— quantity and quality of wastewater, operational parameters, and the cost of conducting measurements.

  • Soft-mode enhanced type-I superconductivity in LiPd2Ge
    • Karolina Górnicka
    • Gabriel Kuderowicz
    • Elizabeth M. Carnicom
    • Kamil Kutorasiński
    • Bartlomiej Wiendlocha
    • Robert J. Cava
    • Tomasz Klimczuk
    2020 Full text PHYSICAL REVIEW B

    The synthesis, crystal structure, and physical properties (magnetization, resistivity, heat capacity) in combination with theoretical calculations of the electronic structure and phonon properties are reported for intermetallic compounds LiPd2X (X = Si, Ge, and Sn). LeBail refinement of powder x-ray diffraction data confirms that all compounds belong to the Heusler family (space group Fm-3m, No. 225). The lattice parameter increases with atomic size of X, and its value varies from a = 5.9059(4) Å for LiPd2Si and a = 6.0082(3) Å for LiPd2Ge, to a = 6.2644(1) Å for LiPd2Sn. The first compound, LiPd2Si, has apparently not been previously reported. All measured quantities demonstrate that LiPd2Ge exhibits superconductivity below Tc = 1.96 K and the normal and superconducting-state data indicate that it is a weak-strength type-I superconductor (C/γ Tc = 1.38) with electron-phonon coupling constant λe−p = (0.53 − 0.56). LiPd2Si and LiPd2Sn are not superconducting above 1.68 K. The experimental observations are supported by theoretical calculations which show that LiPd2Ge has the highest computed λe−p and Tc of the group. A strong softening of the acoustic phonon mode is calculated, and in the case of X = Ge and Sn, imaginary phonon frequencies were computed. The soft mode is most pronounced in the case of LiPd2Ge, which suggests its correlation with superconductivity.

  • Solvent dependency of carbon dioxide Henry's constant in aqueous solutions of choline chloride-ethylene glycol based deep eutectic solvent
    • Ali Reza Harifi-Mood
    • Fereshteh Mohammadpour
    • Grzegorz Boczkaj
    2020 Full text JOURNAL OF MOLECULAR LIQUIDS

    The Henry's constants of carbon dioxide absorbed in aqueous solutions of ethaline (choline chloride-ethylene glycol) were determined for temperatures ranging from 303.15 to 323.15 K based on solubility measurement at CO2 pressure ranging from 0 to 6 bar (0.6 MPa). These studies revealed that the Henry's constant increased with the increase of temperature. Data indicated the highest capacity of CO2 absorption is obtained for ethaline and the lowest temperature dependency of absorption capacity is reported for aqueous solution of ethaline based deep eutectic solvent (0.3 mol fraction of water). The dependence of Henry's constant on solvent composition and solvent properties was investigated using preferential solvation model and linear free energy relationship method. Results showed that CO2 was preferentially solvated by ethaline in aqueous solution. Furthermore it revealed that solute-solvent interactions related to the scale of hydrogen bond donor ability of the solvent were the main parameter which controls the solubility of CO2 in the studied system. Presented methodology is useful for selection of best absorbent composition for systems of hot off-gases treatment. Interesting and practical results obtained in this work, indicated that precisely selected composition of the deep eutectic solvent based absorbent provide low sensitivity of the treatment performance in respect to the temperature of the treated gas.

  • Solvent Impact on the Diversity of Products in the Reaction of Lithium Diphenylphosphide and a Ti(III) Complex Supported by a tBu2P–P(SiMe3) Ligand
    • Aleksandra Ziółkowska
    • Natalia Szynkiewicz
    • Jerzy Pikies
    • Łukasz Ponikiewski
    2020 Full text INORGANIC CHEMISTRY

    We present two important trends in the reactivity ofthe titanium complex [MeNacNacTi(Cl){η2-P(SiMe3)-PtBu2}](MeNacNac− = [Ar]NC(Me)CHC(Me)N[Ar]; Ar = 2,6-iPr2Ph)with nucleophilic reagents RLi (R = Ph2P,tBuO, (Me3Si)2N, andtBu2N) depending on the reaction medium. Reaction in nonpolarsolvent (toluene) leads to three main products: via an autoredoxprocess and nucleophilic substitution at the Ti-atom to afford theTi(IV) complex [MeNacNacTi(R){η2-P-PtBu2}] (1for R = PPh2),via the elimination of Me3SiR to afford Ti(III) complex[MeNacNacTi(Cl){η2-P-PtBu2}]−[Li(12-crown-4)2]+(2), and via2e−reduction process to afford new ionic complex [{ArNC(Me)-CHC(Me)}TiNAr{η1-P(SiMe3)-PtBu2}]−[Li(12-crown-4)2]+(3). Quite differently, the complex [MeNacNacTi(Cl){η2-P(SiMe3)-PtBu2}] reacts with Ph2PLi in THF, unexpectedly yielding two new, four-coordinate Ti(IV) imido complexes4a[{ArNC(Me)CHC(H)(Me)-P(PtBu2)}TiNAr(Cl)]−[Li(12-crown-4)2]+·(toluene)2and4b[{ArNC(CH2)CHC(Me)-P(PtBu2)}TiNAr-(Cl)]−[Li(12-crown-4)2]+·(Et2O). Complex2dissolved in THF converts to4aand4b.1,2,3,4a, and4bwere characterized by X-ray diffraction.1,4a, and4bwere also fully characterized by multinuclear NMR spectroscopy.

  • Some Security Features of Selected IoT Platforms
    • Robert Kałaska
    • Paweł Czarnul
    2020 Full text TASK Quarterly

    IoT (Internet of Things) is certainly one of the leading current and future trends for processing in the current distributed world. It is changing our life and society. IoT allows new ubiquitous applications and processing, but, on the other hand, it introduces potentially serious security threats. Nowadays researchers in IoT areas should, without a doubt, consider and focus on security aspects. This paper is aimed at a high-level review of the existing IoT enabling standalone middleware solutions and frameworks in terms of potential application areas, architecture and components, communication APIs as well as support for key security features including access control, support against attacks on service, device authorization and data filtering. On the one hand, it allows the developer to choose the middleware best matching their needs. On the other hand, it can serve as a starting point for further research on middleware security features based on the provid ed security related open areas and challenges.

  • Sophistication assessment of existing FEM models of orbital blowout trauma: Is models valuation justified?
    • Marcin Zmuda Trzebiatowski
    • Andrzej Skorek
    2020 Journal of Stomatology Oral and Maxillofacial Surgery

    After a thorough study of the work entitled “Development and validation of an optimized finite element model of the human orbit”, some doubts aroused concerning the sophistication assessment of the existing finite element method (FEM) models of orbital blow-out. Although the work was unquestionably innovative, and the results were not only fascinating but also invaluable, the authors stated that their model was the most sophisticated one ever developed to their best knowledge. Hence, the purpose of this letter is to consider whether and upon what circumstances FEM models valuation may be justified.

  • Spatial and vertical distribution analysis of heavy metals in urban retention tanks sediments: a case study of Strzyza Stream
    • Nicole Nawrot
    • Ewa Wojciechowska
    • Karolina Matej-Łukowicz
    • Jolanta Walkusz-miotk
    • Ksenia Pazdro
    2020 Full text ENVIRONMENTAL GEOCHEMISTRY AND HEALTH

    Concentrations of seven heavy metals (HMs): Zn, Cu, Pb, Cd, Ni, Cr, and Fe in core samples of bottom sediments from four retention tanks (RTs) located along the Strzyza Stream in northern Poland (Gdansk) were measured to obtain a general view of sediment quality. The recognition of contamination and potential environmental impacts is the main aim of this paper. A total of 96 sediment samples were collected from eight sampling sites at depths of 0–2 cm, 8–10 cm, 16–18 cm, 24–26 cm. Concentrations of Cu, Zn, Pb, Fe, Ni, and Cr were measured with AAS while Cd concentration was measured with ICP-MS. Granulometric analyses with normalized sieve apertures were carried out. Geochemical indices: enrichment factor, anthropogenic factor, and modified degree of contamination (mCd) were used to assess the contamination level. Concentrations of HMs in sediments changed in the range: Cu (3.24–119 mg/kg d.w.), Zn (12.5–584 mg/kg d.w.), Pb (4.91–309 mg/kg d.w.), Cd (0.003–0.716 mg/kg d.w.), Ni (1.57–25.8 mg/kg d.w.), Cr (2.45–74.5 mg/kg d.w.), and Fe (3993–63817 mg/kg d.w.). The sequential extraction verified the bonding of HMs with non-mobile fractions. Geochemical indices showed widespread pollution by Cu, Pb, Cd, and Zn. Cluster and factor analysis distinguished three related subgroups of HMs: Pb, Ni–Cr, and Fe–Cd–Cu–Zn, suggesting possible common source of each subgroup. Strongly contaminated sediments were distinguished in sediment cores in two middle stream RTs characterized by intense urbanization in their direct catchments.

  • Spatial Differences in the Chemical Composition of Surface Water in the Hornsund Fjord Area: A Statistical Analysis with A Focus on Local Pollution Sources
    • Krystyna Kozioł
    • Ruman Marek
    • Filip Pawlak
    • Stanisław Chmiel
    • Żaneta Polkowska
    2020 Full text Water

    Surface catchments in Svalbard are sensitive to external pollution, and yet what is frequently considered external contamination may originate from local sources and natural processes. In this work, we analyze the chemical composition of surface waters in the catchments surrounding the Polish Polar Station in Svalbard, Hornsund fjord area. We have pooled unpublished and already published data describing surface water composition in 2010, related to its pH, electrical conductivity (EC), metals and metalloids, total organic carbon (TOC) and selected organic compound concentrations, including persistent organic pollutants (POPs) and surfactants. These data were statistically analyzed for spatial differences, using Kruskal–Wallis ANOVA and principal component analysis (PCA), with distance from the station in the PCA approximating local human activity impact. The geological composition of the substratum was found to be a strong determinant of metal and metalloid concentrations, sufficient to explain significant differences between the studied water bodies, except for the concentration of Cr. The past and present human activity in the area may have contributed also to some of the polycyclic aromatic hydrocarbons (PAHs), although only in the case of naphthalene can such an effect be confirmed by an inverse correlation with distance from the station. Other likely factors contributing to the chemical concentrations in the local waters are marine influence, long-range pollution transport and release from past deposition in the environment.

  • Special Issue: “Non-Destructive Testing of Structures”
    • Magdalena Rucka
    2020 Full text Materials

    The Special Issue “Non-Destructive Testing of Structures” has been proposed to present recent developments in the field of diagnostics of structural materials and components in civil and mechanical engineering. The papers highlighted in this editorial concern various aspects of non-invasive diagnostics, including such topics as condition assessments of civil and mechanical structures and connections of structural elements, the inspection of cultural heritage monuments, the testing of structural materials, structural health monitoring systems, the integration of non-destructive testing methods, advanced signal processing for the non-destructive testing of structures (NDT), damage detection and damage imaging, as well as modeling and numerical analyses for supporting structural health monitoring (SHM) systems.

  • Special Issue: Recent Advances in Corrosion Science
    • Jacek Ryl
    2020 Full text Materials

    The dynamic development of the global industry and growing demand for new material technologies generates constantly increasing problems regarding premature material degradation and the requirement to determine corrosion mechanisms and to develop new protection/evaluation approaches. This Special Issue, “Recent Advances in Corrosion Science”, brings together fourteen articles and one review, providing a snapshot of the recent activity and development in this field.

  • Speciation of heavy metals in bottom sediments of drinking water reservoir for Gdansk, Poland – changes over the 14 years
    • Eliza Kulbat
    • Aleksandra Sokołowska
    2020 Desalination and Water Treatment

    There was conducted a comparative study of the concentrations of heavy metals (Zn, Cu, Pb, and Cd) in the surface layer of sediments collected in two investigation periods: 1999–2000 and 2013. Theresults demonstrated that the degree of metals pollution decreased over time. The contamina-tion factors (Cf) calculated for Zn, Cu, Pb, and Cd were respectively 3.63, 3.86, 3.23, and 3.25 in the first period of research and 1.35, 3.42, 1.98, and 1.43 in the second one. The metal speciation analysis indicated that Zn was mainly associated with the Fe–Mn oxides fraction and the residual fraction, and Cu – with the residual fraction and the organic fraction in both periods of investigation, while the percentage of geochemical fractions in binding of Pb and Cd changed in time. The share of fractions Fe–Mn oxides/carbonate increased in the case of Pb, and carbonate/exchangeable fractions in the case of Cd. The risk assessment code (RAC) decreased in the following order: Cd>Zn>Pb>Cu and was higher in 2013 - it achieved the very high-risk category in the case of Cd. Thus, despite the decrease of sediment pollution, RAC for Cd increased due to changed geochemical speciation.

  • Spectroscopic Optical Coherence Tomography for Thin Layer and Foil Measurements
    • Aleksandra Kamińska
    • Marcin Strąkowski
    • Jerzy Pluciński
    2020 Full text SENSORS

    The main goal of this research was to assess if it is possible to evaluate the thickness of thin layers (both thin films on the surface and thin layers below the surface of the tested object) and foils using optical coherence tomography (OCT) for thickness assessment under the resolution of the standard commercially available OCT measurement system. In the proposed solution, light backscattered from the evaluated thin layer has been expressed as a multiple beam interference. Therefore, the OCT system was modeled as a two-beam interferometer (e.g., Michelson), in which one beam propagates from the reference arm and the other comes from a Fabry–Pérot interferometer. As a consequence, the mathematical model consists of the main Michelson interferometer, in which the measuring arm represents the Fabry–Pérot interferometer. The parameters of the layer (or foil) are evaluated by analyzing the minimum value of the interference contrast. The model developed predicts the behavior of the thin layers made from different materials (with different refractive indexes) with different thickness and located at different depths. To verify the correctness of the proposed model, an experiment with a wedge cell has been carried out. The wedge cell was shifted across the scanning beam using a linear translation stage with a micrometer screw under the scanning head. The relationship between the thickness of the gap of the wedge cell and the OCT output signal is presented. For the additional verification of the proposed model, the results of the measurements of the thickness of the thin foil were compared with the theoretical results of the simulations. The film thickness was evaluated based on the calculated positions of the minimum value of interference contrast. A combination of the standard potentialities of OCT with the proposed approach to analyzing the signal produces new metrological possibilities. The method developed allows us to evaluate thickness under the resolution of the system and the location of the layer as well. This produces the possibility of measuring a layer which is covered by another layer. Moreover, it is possible to create a thickness map with high sensitivity to thickness changes. These experiments and simulations are the culmination of preliminary research for evaluating the potential of the proposed measurement method.

  • Spectroscopic studies of Nb-doped tricalcium phosphate glass-ceramics prepared by sol-gel method
    • Wojciech Korzeniewski
    • Agnieszka Witkowska
    • Maciej Manecki
    2020 Synchrotron Radiation in Natural Science

    Calcium-phosphate based glasses and glass-ceramics play a crucial role in the tissue engineering development. Apart from their high biocompatibility and excellent ability to undergo varying degrees of resorbability1, they exhibit relatively high bioactivity and due to that they are commonly used as bone and dental implants. A substantial research effort is devoted to improve calcium-phosphate materials physico-chemical properties by tuning their degree of crystallinity and doping them with metal ions is one of the mostly researched strategies. The results found in the literature show that synthesized CaOP2O5-Nb2O5 compounds exhibit a good biocompatibility, very low cytotoxicity in respect to calciumphosphate doped with other metals and additionally can enhance human osteoblast function2,3. As of today structure of these materials is not thoroughly described. Therefore, the detailed structural investigation by means of spectroscopic studies, i.e. FTIR spectroscopy, Raman spectroscopy, XAFS spectroscopy, XPS and EDX, together with SEM imaging, XRD and BET surface area measurements, was realized to shed light on the relationship between materials structure and the presence of dopant. In this work, we show the results obtained for bioactive glass-ceramics, prepared via simple sol-gel method, with Ca/(P+Nb) molar ratio equal to 1.5 and with relative Nb contents of 0 mol% and 10 mol% of P. XRD patterns analysis shows that samples consist of tricalcium phosphate and hydroxyapatite phase. Raman spectra analysis confirms the incorporation of Nb into the material structure. Moreover, niobium doping leads to an increase in degree of crystallinity and crystallite size of the sample. Stoichiometry of the ceramics is as intended. Additionally, there is a greater proportion of carbonate groups in the doped material than in the undoped one (FTIR, Raman spectroscopy), and all samples exhibit calcium deficiency on the surface (XPS). XAFS analysis shows presence of octahedral coordination of niobium ions, with average oxidation state around +4.5 and XPS analysis indicates that on the sample surface the contribution of Nb+5 ions is greater than Nb+4 ions. Additionally it can be concluded, that Nb accumulates on materials surface.

  • Spinon excitations in the quasi-one-dimensional S=12 chain compound Cs4CuSb2Cl12
    • Thao Tran
    • Chris A. Pocs
    • Yubo Zhang
    • Michał Winiarski
    • Jianwei Sun
    • Minhyea Lee
    • Tyrel McQueen
    2020 Full text PHYSICAL REVIEW B

    The spin−1/2 Heisenberg antiferromagnetic chain is ideal for realizing one of the simplest gapless quantum spin liquids (QSLs), supporting a many-body ground state whose elementary excitations are fractional fermionic excitations called spinons. Here we report the discovery of such a one-dimensional (1D) QSL in Cs4CuSb2Cl12. Compared to previously reported S=1/2 1D chains, this material possesses a wider temperature range over which the QSL state is stabilized. We identify spinon excitations extending at T>0.8K, with a large T-linear contribution to the specific heat, γ=31.5(2)mJmol−1K−2, which contribute itinerantly to thermal transport up to temperatures as high as T=35K. At T=0.7K, we find a second-order phase transition that is unchanged by a μ0H=5T magnetic field. Cs4CuSb2Cl12 reveals new phenomenology deep in the 1D QSL regime, supporting a gapped QSL phase over a wide temperature range compared to many other experimental realizations.

  • Spirala 2 (wg Ulama) z cyklu No Quick Response
    • Krzysztof Wróblewski
    2020

    Spirala 2 (wg Stanisława Ulama) Obraz odnosi się do modelu matematycznego nazywanego Spiralą Ulama, który polega na okrężnym zapisie w polu kwadratu liczb naturalnych od 1 do nieskończoności. Taki zapis uwidacznia szczególne wzory, które powstają z położenia liczb pierwszych (niepodzielnych). Liczby pierwsze tworzą ciągi mniej lub bardziej regularne w układzie diagonalnym, poziomym i pionowym. W obrazie Spirala 2 wykorzystany został zestaw liczb od 1 do 1600. Położenia liczb pierwszych są malowane czernią i bielą, natomiast położenie pozostałych liczb kolorami podstawowymi i pochodnymi w różnej tonacji. Kolory "wędrują" progresywnie za liczbami po kształcie spirali. Sekwencyjny rytm przerywany jest położeniem liczby pierwszej. W wyniku tego zabiegu samorzutnie powstają grupy różnych form i kolorów, przy czym żadna z nich nie jest dominująca w całości układu. Poszczególne kształty są tylko cząstkami większej całości. W spirali Ulama podobnie jak w ciągu Fibonacciego występuje rodzaj harmonijnej jedności. Krzysztof Wróblewski

  • Społeczna odpowiedzialność biznesu w branży odzieżowej - perspektywa polskiego konsumenta
    • Ewa Marjańska
    • Piotr Grudowski
    • Anna Wendt
    • Mateusz Muchlado
    2020 Problemy Jakości

    Przesunięcie produkcji do krajów dotkniętych ubóstwem towarzyszy podejściu kładącemu nacisk na szybkie odpowiedzialność i tanie udostępnianie trendów modowych konsumentom oraz systemowi wytwarzania opartemu na popycie biznesu, w przemyśle odzieżowym. W artykule zwrócono uwagę na: świadomość, postawy, zachowania etyczne oraz zrównoważony sposób postrzegania jakości produktów „fast fashion” w perspektywie społecznej odpowiedzialności. Na rozwój, podstawie metody CAWI i PAPI przeprowadzono badanie polskich konsumentów deklarujących zachowania przemysł odzieżowy, nabywcze związane z „fast fashion”. Badania wykazały, że działania związane ze społeczną odpowiedzialnością fast fashion biznesu w branży odzieżowej są istotne dla klientów, jednak cena jest najważniejszym czynnikiem przy podejmowaniu decyzji o zakupie. Ocena świadomości konsumentów w zakresie CSR może posłużyć do ukierunkowania przyszłych działań edukacyjnych w tym obszarze, zwłaszcza w dobie przyspieszonej konsumpcji i celów zrównoważonego rozwoju. Wyniki badań mogą też być przesłanką do określenia kierunku działań związanych z CSR dla sprzedawców „fast fashion”.

  • Społeczna odpowiedzialność biznesu w kontekście strategii wybranych spółek posiadających istotne znaczenie dla gospodarki
    • Sebastian Skuza
    • Anna Modzelewska
    • Malwina Popiołek
    • Marta Szeluga-Romańska
    2020

    Przedmiotem badań jest analiza sposobów realizacji strategii społecznej odpowiedzialności biznesu przez przez wybrane spółki z udziałem Skarbu Państwa.

  • Stability analysis of interconnected discrete-time fractional-order LTI state-space systems
    • Łukasz Grzymkowski
    • Damian Trofimowicz
    • Tomasz Stefański
    2020 Full text International Journal of Applied Mathematics and Computer Science

    In this paper, a stability analysis of interconnected discrete-time fractional-order (FO) linear time-invariant (LTI) state-space systems is presented. A new system is formed by interconnecting given FO systems using cascade, feedback, parallel interconnections. The stability requirement for such a system is that all zeros of a non-polynomial characteristic equation must be within the unit circle on the complex z-plane. The obtained theoretical results lead to a numerical test for stability evaluation of interconnected FO systems. It is based on modern root-finding techniques on the complex plane employing triangulation of the unit circle and Cauchy’s argument principle. The developed numerical test is simple, intuitive and can be applied to a variety of systems. Furthermore, because it evaluates the function related to the characteristic equation on the complex plane, it does not require computation of state-matrix eigenvalues. The obtained numerical results confirm the efficiency of the developed test for the stability analysis of interconnected discrete-time FO LTI state-space systems.

  • Stability analysis of nanobeams in hygrothermal environment based on a nonlocal strain gradient Timoshenko beam model under nonlinear thermal field
    • Subrat Kumar Jena
    • S. Chakraverty
    • Mohammad Malikan
    2020 Full text Journal of Machinery Manufacture and Reliability

    This article is dedicated to analyzing the buckling behavior of nanobeam subjected to hygrothermal environments based on the principle of the Timoshenko beam theory. The hygroscopic environment has been considered as a linear stress field model, while the thermal environment is assumed to be a nonlinear stress field based on the Murnaghan model. The size-dependent effect of the nanobeam is captured by the nonlocal strain gradient theory (NSGT), and the governing equations of the proposed model have been derived by implementing a variational principle. The critical buckling loads have been calculated for the hinged–hinged boundary condition by incorporating the Navier approach and considering other elasticity theories such as classical elasticity theory, Eringen nonlocal elasticity theory, and strain gradient theory along with the NSGT. The present model is also validated with the pre-existing model in exceptional cases. Further, a parametric investigation has been performed to report the influence of various scaling parameters like hygroscopic environment, thermal environment, length-to-diameter ratio, small scale parameter, and length scale parameter on critical buckling loads by considering both the linear and nonlinear temperature distributions.

  • Stabilizing lactate production through repeated batch fermentation of food waste and waste activated sludge
    • Xianbao Xu
    • Wenjuan Zhang
    • Xia Gu
    • Zhichao Guo
    • Jian Song
    • Daan Zhu
    • Yanbiao Liu
    • Yanan Liu
    • Gang Xue
    • Xiang Li
    • Jacek Mąkinia
    2020 BIORESOURCE TECHNOLOGY

    Bio-valorization of organic waste streams, such as food waste and waste activated sludge, to lactic acid (LA) has recently drawn much attention. It offers an opportunity for resource recovery, alleviates environmental issues and potentially turns a profit. In this study, both stable and high LA yield (0.72 ± 0.15 g/g total chemical oxygen demand) and productivity rate (0.53 g/L•h) were obtained through repeated batch fermentation. Moreover, stable solubilization and increase in the critical hydrolase activities were achieved. Depletions of ammonia and phosphorus were correlated with the LA production. The relative abundance of the key LA bacteria genera (i.e., Alkaliphilus, Dysgonomonas, Enterococcus and Bifidobacterium) stabilized in the repeated batch reactor at a higher level (44.5 ± 2.53%) in comparison with the batch reactor (26.2 ± 4.74%). This work show a practical way for the sustainable valorization of organic wastes to LA by applying the repeated batch mode during biological treatment.

  • Standardy Profesjonalnego Public Relations
    • Jacek Barlik
    • Ewa Hope
    • Jerzy Olędzki
    • Krystyna Wojcik
    2020

    " Standardy przedstawiają wartości i pryncypia uzasadniające konieczność dokonywania odpowiednich wyborów. Public relations ma godzić interesy zleceniodawców, przedstawicieli mediów i różnych grup społeczeństwa, a przy tym pozostawać w zgodzie z normami etycznymi i odwoływać się do takich wartości jak szacunek, godność, rzetelność, uczciwość, prawda, wiarygodność, niezależność, lojalność i zaufanie. Opracowanie "Standardów profesjonalnego Public Relations" zostało przygotowane przez społeczny zespół ekspertów - autorzy dokumentu, w przekonaniu, że profesjonalizm i etyka są ze sobą nierozerwalnie połączone -zwłaszcza w dziedzinach, które - jak PR, wpływają na kondycję społeczeństwa."

  • Stanowisko laboratoryjne do badania procesów wibroakustycznych w rejonie głowicy cylindrowej silnika z zapłonem samoczynnym - wyniki badań pilotażowych
    • Jacek Rudnicki
    2020 Full text Journal of Polish CIMEEAC

    W artykule przedstawiono założenia oraz ich praktyczną realizację w odniesieniu do stanowiska laboratoryjnego przeznaczonego do badania procesów wibroakustycznych w rejonie głowicy silnika z zapłonem samoczynnym. Podstawowym założeniem podczas realizacji tego projektu było stworzenie możliwości dydaktycznych oraz naukowo – badawczych w zakresie obserwacji i rejestracji procesów drganiowych w rejonie głowicy cylindrowej silnika z zapłonem samoczynnym podczas pracy układu rozrządu napędzane go ze źródła zewnętrznego. Umożliwia to wyselekcjonowanie prawie „czystej” postaci tych procesów, pochodzących wyłącznie od pracy układu rozrządu bez zakłóceń spowodowanych pracą innych przekładni i mechanizmów w rzeczywistym silniku oraz zjawisk gazodynamicznych związanych ze spalaniem. Fakt ten pozwala na rejestrację wartości wybranych wskaźników opisujących drgania tego węzła konstrukcyjnego silnika, odpowiednie opracowanie powstałych zapisów i ich ewentualne wykorzystanie we wnioskowaniu diagnostycznym np. w zakresie oceny faz rozrządu. Innym sposobem wykorzystania tak uzyskanych wyników jest możliwość wykorzystania tych zapisów do filtracji wyników uzyskanych na obiekcie rzeczywistym czyli funkcjonującym silniku.

  • Stanowisko wizualizacji zdarzeń w systemie STRADAR – realizacja i funkcje dla operatora
    • Bartosz Czaplewski
    • Sylwester Kaczmarek
    • Jacek Litka
    2020 Full text Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    It is crucial for the Border Guard to be equipped with a communication-teleinformatic infrastructure designed to support them in efficient realization of their operational tasks. STRADAR – a system which results are presented in this paper – is such an infrastructure. It is a distributed solution for the maritime division of the border guard. The system, with the use of a network of sensors located in both stationary and mobile points collects, archives and processes information and multimedia data, which can be made available to the staff on their demand. STRADAR consists of a number of functional elements. The paper includes a detailed description of one of them. This element being Event Visualization Post EVP, which utilizes multidisplay set up in the Centrum, to display multimedia presentation of information and data for both archival and current situations.

  • Static and Dynamic Mechanical Properties of 3D Printed ABS as a Function of Raster Angle
    • Mateusz Galeja
    • Aleksander Hejna
    • Paulina Kosmela
    • Arkadiusz Kulawik
    2020 Full text Materials

    Due to the rapid growth of 3D printing popularity, including fused deposition modeling (FDM), as one of the most common technologies, the proper understanding of the process and influence of its parameters on resulting products is crucial for its development. One of the most crucial parameters of FDM printing is the raster angle and mutual arrangement of the following filament layers. Presented research work aims to evaluate different raster angles (45°, 55°, 55’°, 60° and 90°) on the static, as well as rarely investigated, dynamic mechanical properties of 3D printed acrylonitrile butadiene styrene (ABS) materials. Configuration named 55’° was based on the optimal winding angle in filament-wound pipes, which provides them exceptional mechanical performance and durability. Also in the case of 3D printed samples, it resulted in the best impact strength, comparing to other raster angles, despite relatively weaker tensile performance. Interestingly, all 3D printed samples showed surprisingly high values of impact strength considering their calculated brittleness, which provides new insights into understanding the mechanical performance of 3D printed structures. Simultaneously, it proves that, despite extensive research works related to FDM technology, there is still a lot of investigation required for a proper understanding of this process.

  • Step on It Bringing Fullwave Finite-Element Microwave Filter Design up to Speed
    • Łukasz Balewski
    • Grzegorz Fotyga
    • Adam Lamęcki
    • Michał Mrozowski
    • Martyna Mul
    • Piotr Sypek
    • Damian Szypulski
    2020 Full text IEEE MICROWAVE MAGAZINE

    There are many steps in the design of a microwave filter: mathematically describing the filter characteristics, representing the circuit as a network of lumped elements or as a coupling matrix, implementing the distributed elements, finding the initial dimensions of the physical structure, and carrying out numerical tuning using electromagnetic (EM) simulators. The whole process is painstaking and time-consuming, and it requires a great deal of engineering expertise. Microwave filters are extremely complex geometric structures, and their simple circuits are often quite hard to represent. Moreover, manufacturing them is costly: to be sure that the hardware resulting from the design will meet the performance goals, rigorous computer tools are used to determine the physical dimensions and evaluate all of the adjustments at the final stage. This last stage is particularly challenging, and advanced computational techniques are required.

  • Storage electric multiple units on partially electrified suburban railway lines
    • Aleksander Jakubowski
    • Natalia Karkosińska-Brzozowska
    • Krzysztof Karwowski
    • Andrzej Wilk
    2020 Full text Przegląd Elektrotechniczny

    The paper presents possible environmental, energy and economical gains implied by replacing conventional traction vehicles with independent powered electric multiple units (IPEMU) on partially electrified suburban railways. IPEMUs can operate in two modes of power supply – using overhead catenary or onboard battery storage. Appropriate computer simulations were carried out in the Matlab program, indicating the parameters of storage electric multiple units.

  • Strategic Flexibility as a Mediator in Relationship between Managerial Decisions and Organizational Learning: Ambidexterity Perspective
    • Monika Stelmaszczyk
    • Agata Pierścieniak
    2020 Full text European Research Studies Journal

    Purpose: The purpose of the article is to determine strategic flexibility in the relationship between managerial decisions and organizational learning. The analyses are conducted in the ambidexterity convection. Design/Methodology/Approach: The study was conducted at a textile company. The company is a leader in the textile recycling industry in Poland. Empirical data were collected using the PAPI technique. The survey questionnaire was addressed to all 138 company managers. The response rate was 57%. Linear regression analyses were performed to test the research hypotheses. The significance of indirect effects was checked using the bootstrap method. Findings: Our findings show that as the ambidexterity oriented managerial decisions increases, the organizational learning ambidexterity increases. This relationship mediates strategic flexibility through variable flexibility resources and flexibility coordination. In fact, we have indicated the effect of double mediation. This means that there is a relationship between the independent variable and the dependent variable because of interacting resource flexibility and coordination flexibility. Practical Implications: Our study shows that managerial decisions in the company will become more conducive for improving current ideas and introducing new ideas, including ways of their implementation if the enterprise undertakes the proposed steps. They include the acquisition of resources, to develop practical skills, to care in maintaining relatively low costs and shortening task execution duration, to be able to switch to alternative uses of resources. Originality/Value: The value of our research is gaining new knowledge about strategic flexibility. Arguing its necessity for the existence of relationships between managerial decisions and organizational learning, using the ambidexterity convention, improves the knowledge regarding the identity of this category of flexibility.

  • Stratification of nano-pigments in anti-corrosive coatings by means of magnetic field
    • Andrzej Miszczyk
    • Kazimierz Darowicki
    2020 Full text PROGRESS IN ORGANIC COATINGS

    The concept of self-stratification of coatings, although attractive, causes difficulties in its practical use, especially when pigments are added to the resins. An alternative way of obtaining a multilayer structure in a single step was presented. Using the inhomogeneous magnetic field and magnetically active components of the coating, the possibility of vertically graded differentiation of the one layer properties has been verified. For this purpose, the magnetic properties of nickel ferrite (NiFe2O4) nano-particles and magnetic field for their transport in a wet coating were used. It has been shown that it is possible to use the magnetic field to transport magnetic ferrite, used as active anticorrosive pigments, near the coating/substrate interface, in the initially homogeneous wet paint layer, during film formation. These results prove that magnetic ferrite pigments can be magnetically manipulated in liquid coating layer applied on the substrate. Using the impedance spectroscopy technique, it was possible to detect stratification by analyzing complex capacity diagrams. As a result of impedance tests, better anti-corrosive properties of the system hardened in the presence of the magnetic field were demonstrated.

  • Stream Reasoning to Improve Decision-Making in Cognitive Systems
    • Caterine Silva de Oliveira
    • Franco Giustozzi
    • Cecilia Zanni-Merk
    • Cesar Sanin
    • Edward Szczerbicki
    2020 Full text CYBERNETICS AND SYSTEMS

    ABSTRACT Cognitive Vision Systems have gained a lot of interest from industry and academia recently, due to their potential to revolutionize human life as they are designed to work under complex scenes, adapting to a range of unforeseen situations, changing accordingly to new scenarios and exhibiting prospective behavior. The combination of these properties aims to mimic the human capabilities and create more intelligent and efficient environments. Contextual information plays an important role when the objective is to reason such as humans do, as it can make the difference between achieving a weak, generalized set of outputs and a clear, target and confident understanding of a given situation. Nevertheless, dealing with contextual information still remains a challenge in cognitive systems applications due to the complexity of reasoning about it in real time in a flexible but yet efficient way. In this paper, we enrich a cognitive system with contextual information coming from different sensors and propose the use of stream reasoning to integrate/process all these data in real time, and provide a better understanding of the situation in analysis, therefore improving decision-making. The proposed approach has been applied to a Cognitive Vision System for Hazard Control (CVP-HC) which is based on Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA) and has been designed to ensure that workers remain safe and compliant with Health and Safety policy for use of Personal Protective Equipment (PPE).

  • Stress Monitoring System for Individuals with Autism Spectrum Disorders
    • Michał Tomczak
    • Marek Wójcikowski
    • Bogdan Pankiewicz
    • Jacek Łubiński
    • Jakub Majchrowicz
    • Daria Majchrowicz
    • Anna Walasiewicz
    • Tomasz Kiliński
    • Małgorzata Szczerska
    2020 Full text IEEE Access

    In this article, a stress monitoring system tailored for individuals with Autism Spectrum Disorders (ASD) and developed for the educational institution is presented. People with ASD face problems with effective stress management due to their high self-perceived levels of stress, poor ability to cope with it, and dificulties with the accurate detection of the source of stress. Consistently, being able to measure stress appears to be highly vital for this specifc group. The design and construction of the measuring system are introduced. The stress monitoring system including autonomic wearable device (wristband), both the electronics and mechanical part, as well as the software application for data analysis are shown. The wearable device includes sensors for measuring heart rate, skin resistance, temperature and movement. A dedicated software application allows for generating reports to evaluate therapeutic effects. The complex stress monitoring system has been tested in an educational institution. It can provide signifcant support in the stress management of people with ASD and become a meaningful assistance in the therapy of neurodiverse individuals.

  • Stress-driven nonlocal elasticity for nonlinear vibration characteristics of carbon/boron-nitride hetero-nanotube subject to magneto-thermal environment
    • Hamid M. Sedighi
    • Mohammad Malikan
    2020 Full text PHYSICA SCRIPTA

    Stress-driven nonlocal theory of elasticity, in its differential form, is applied to investigate the nonlinear vibrational characteristics of a hetero-nanotube in magneto-thermal environment with the help of finite element method. In order to more precisely deal with the dynamic behavior of size-dependent nanotubes, a two-node beam element with six degrees-of freedom including the nodal values of the deflection, slope and curvature is introduced. In comparison with the conventional beam element, the vector of nodal displacement for the proposed element has one additional component indicating the nodal curvature to comply with the stress-driven nonlocal beam model. The nonlinear term associated with the von Kármán strain is included in the governing equation of motion and it is assumed that the nanotube structure is exposed to temperature changes and surrounded by a magnetic field. The obtained results endorsing the amplitude-dependence of the nonlinear frequencies are justified compared to those reported in the literature and a detailed study is conducted to explore the effect of different parameters on the vibrational behavior of the considered nano-hetero-structure.

  • Striking elements - A lifebelt or a fad? Searching for an effective way of adapting abandoned churches.
    • Agnieszka Szuta
    • Jakub Szczepański
    2020 Full text Frontiers of Architectural Research

    Are avant-garde elements added to historical objects as a temporary fashion to fulfill the aspirations of designers or an attempt to draw attention to themselves? It may be the exact opposite, and this type of controversial project is the best lifebelt for such monuments. This article explores issues related to external avant-garde elements added to adapted churches and their influence on the efficiency of such adaptation projects. Gothic churches located in the north of Europe that have changed their religious function, entirely or in part, were considered. This work examined former churches in Maastricht, namely, the Minorite Church, the Church of the Kruisheren Monastery, the Dominican Church, as well as Polish churches located in Gda nsk, including St. John’s Church and St. Catherine’s Church. This article attempted to identify the factors that contribute to the successful adaptation of former churches and the benefits and drawbacks of adopting avant-garde design solutions. Results of this study might provide valuable inspiration for other churches that are losing worshippers. This study was conducted on the basis of a wide range of literature, statistical data, logical reasoning, and comparative methods. Observations from selected edifices were checked for their correlation over time. This study also included in situ investigations.

  • Structural and catalytic properties of ceria layers doped with transition metals for SOFCs fueled by biogas
    • Bartosz Hołówko
    • Patryk Błaszczak
    • Mikołaj Chlipała
    • Maria Gazda
    • Sea-Fue Wang
    • Piotr Jasiński
    • Beata Bochentyn
    2020 Full text INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    The aim of this paper was to investigate an influence of the nanocrystalline Ce0.8A0.2O2-δ (A = Mn, Fe, Co, Ni, Cu) materials on the direct internal reforming of biogas in SOFC. Structural analysis of fabricated compounds has been done. An in-situ analysis of a composition of outlet gases from operating SOFC was performed using FTIR spectroscopy with simultaneous electrical tests. It was found out, that type of dopant strongly affects biogas reforming process. The differences in absolute values of current density resulted mostly from a microstructure and probably phase composition of a deposited layers. Fuel cells with Ce0.8Co0.2O2-δ and Ce0.8Ni0.2O2-δ additional layers presented the highest drop of current density after switching from hydrogen to biogas, but simultaneously they were the most stable in time. Additional chemical analysis revealed that steam reforming and methane pyrolysis might be dominating reactions while working in biogas atmosphere.

  • Structural and Temporal Topic Models of Feedbacks on Service Quality – A Path to Theory Development?
    • Ojo Adegboyega
    • Nina Rizun
    2020

    There is growing interest in applying computational methods in analysing large amount of data without sacrificing rigour in Information Systems research. In this paper, we demonstrate how the use of structural and temporal topic modelling can be employed to produce insights of both theoretical and practical importance from the analysis of textual comments on the quality of services in hospitals. As a first step, we revealed the thematic structures in the comments as topics which were aligned with the SERVQUAL dimensions. Following this, we established the temporal precedence among SERVQUAL factors based on the evolution of the topics over time. Theoretically, our findings are consistent with the emerging consensus on the nature of SERVQUAL dimensions from extant quantitative research and offer new propositions on the relationships among these dimensions. From the practice perspective, we produced quantified measures of factors associated with healthcare service experience

  • Structural Assessment of Reinforced Concrete Beams Incorporating Waste Plastic Straws
    • Jamal M. Khatib
    • Ali Jahami
    • Adel Elkordi
    • Hakim Abdelgader
    • Mahammed Sanebi
    2020 Full text Environments

    The behavior of reinforced concrete beams containing fibers made of waste plastic straws (WPSs) under the three point bending test is examined. The effect of WPS fiber addition on the compressive and split tensile strength is reported. Four concrete mixes were prepared. The control mix PS-0 had a proportion of 1 cement: 1 sand: 2 coarse aggregate and a water cement ratio of 0.4. In the other three mixes PS-0.5, PS-1.5 and PS-3, 0%, 0.5%, 1.5% and 3% of WPS fiber (by volume) was added respectively. The results show that at 0.5% WPS, there is slight increase in compressive strength. However, beyond 0.5% addition, a decrease in compressive strength is observed. The split tensile strength shows a systematic increase with the addition of WPS fibers. The reinforced concrete beams containing WPS fibers show higher ductility as demonstrated by the larger ultimate tensile strain and ductility index (Δu/Δy). There is a tendency to have more fine cracks with the presence of WPS fibers.

  • Structural Insights into New Bi(III) Coordination Polymers with Pyridine-2,3-Dicarboxylic Acid: Photoluminescence Properties and Anti-Helicobacter pylori Activity
    • Mateusz Kowalik
    • Joanna Masternak
    • Iwona Łakomska
    • Katarzyna Kazimierczuk
    • Anna Zawilak-Pawlik
    • Piotr Szczepanowski
    • Oleksiy Khavryuchenko
    • Barbara Barszcz
    2020 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Two novel coordination polymers, [Bi2(2,3pydc)2(2,3pydcH)2(H2O)]n(1) and {(Et3NH)2[Bi(2,3pydc)(2,3pydcH)Cl2]}n(2) were prepared using as a prolinker pyridine-2,3-dicarboxylic acid(2,3pydcH2). The obtained complexes were fully characterized by elemental analysis, TG/DTG, FT-IR,solid-state photoluminescence, DFT calculations and single-crystal X-ray diffraction. The obtainedcomplexes crystallized in the triclinicP-1 space group (1) and comprise dimeric units with twocrystallographically different Bi(III) centers (polyhedra: distorted pentagonal bipyramid andbicapped trigonal prism) and monoclinicP21/cspace group (2) with a distorted monocappedpentagonal bipyramid of Bi(III) center. The various coordination modes of bridging carboxylateligands are responsible for the formation of 1D chains with4,5C10(1) and2C1(2) topology.The photoluminescence quantum yield for polymer2is 8.36%, which makes it a good candidate formore specific studies towards Bi-based fluorescent materials. Moreover, it was detected that polymer1is more than twice as active againstH. pylorias polymer2. It can be concluded that there is anexisting relationship between the structure and the antibacterial activity because the presence ofchloride and triethylammonium ions in the structure of complex2reduces the antibacterial activity.

  • Structural, magnetic and spectral properties of tetrahedral cobalt(II) silanethiolates: a variety of structures and manifestation of field-induced slow magnetic relaxation
    • Daria Kowalkowska-Zedler
    • Anna Dołęga
    • Natalia Nedelko
    • Renata Łyszczek
    • Pavlo Aleshkevych
    • Iraida Demchenko
    • Justyna Łuczak
    • Anna Ślawska-waniewska
    • Agnieszka Pladzyk
    2020 DALTON TRANSACTIONS

    Blue crystals of five heteroleptic cobalt(II) silanethiolates 1–5 have been obtained by the reaction of [Co{SSi (tBuO)3}2(NH3)]2 with aminopyridines and aminomethylpyridines at an appropriate molar ratio and their structural, spectral, thermal and magnetic properties have been established and described. All complexes 1–5 contain Co(II) ions in a tetrahedral CoN2S2 environment formed by (tBuO)3SiS− residues and pyridines and present variable structures. Complexes 1–3 are mononuclear [Co{SSi(tBuO)3}2(L1)2] (L1 = 2-aminopyridine 2AP, 3-aminopyridine 3AP, and 4-aminopyridine 4AP). The application of 3AMP and 4AMP (3-aminomethylpyridine and 4-aminomethylpyridine) allows either dinuclear complex 4 [Co{SSi(tBuO)3}2(μ-3AMP)]2 or 1D coordination polymer 5 with the formula of [Co{SSi(tBuO)3}2(μ-4AMP)]n to be obtained. The molecular structures of 1–5 were determined by single-crystal X-ray and powder diffraction, UV-vis and FTIR spectrocopy for solid samples and their thermal properties were characterized by TG-DSC and TG-FTIR methods. The dc and ac magnetic and EPR studies of polycrystalline samples have been performed. For all complexes, the obtained data show a behavior typical of paramagnetic high–spin Co(II) ions in a tetrahedral geometry, with a considerable contribution of the ZFS effect in a low temperature range. All complexes were also probed for SIM behavior. The modeling of the magnetic and EPR data was done for samples 1, 3, 4 and 5 to estimate ZFS parameters. The obtained results imply a negative value of the axial parameter D in complex 4 and positive D values for the rest of the compounds. A comparative magneto-structural analysis of complexes 4 and 5 points to the high sensitivity of the single-ion magnetic anisotropy of tetrahedral Co (II) complexes to subtle changes in the first and second coordination spheres of Co(II) ions.

  • Structural Properties and Water Uptake of SrTi1−xFexO3−x/2−δ
    • Tadeusz Miruszewski
    • Kacper Dzierzgowski
    • Piotr Winiarz
    • Sebastian Wachowski
    • Aleksandra Mielewczyk-Gryń
    • Maria Gazda
    2020 Full text Materials

    In this work, Fe-doped strontium titanate SrTi1−xFexO3−x/2−δ, for x = 0–1 (STFx), has been fabricated and studied. The structure and microstructure analysis showed that the Fe amount in SrTi1−xFexO3−x/2−δ has a great influence on the lattice parameter and microstructure, including the porosity and grain size. Oxygen nonstoichiometry studies performed by thermogravimetry at different atmospheres showed that the Fe-rich compositions (x > 0.3) exhibit higher oxygen vacancies concentration of the order of magnitude 1022–1023 cm−3. The proton uptake investigations have been done using thermogravimetry in wet conditions, and the results showed that the compositions with x < 0.5 exhibit hydrogenation redox reactions. Proton concentration at 400 °C depends on the Fe content and was estimated to be 1.0 × 10−2 mol/mol for SrTi0.9Fe0.1O2.95 and 1.8 × 10−5 mol/mol for SrTi0.5Fe0.5O2.75. Above 20 mol% of iron content, a significant drop of proton molar concentrations at 400 °C was observed. This is related to the stronger overlapping of Fe and O orbitals after reaching the percolation level of approximately 30 mol% of the iron in SrTi1−xFexO3−x/2−δ. The relation between the proton concentration and Fe dopant content has been discussed in relation to the B-site average electronegativity, oxygen nonstoichiometry, and electronic structure.

  • Structure and water uptake in BaLnCo2O6−δ (Ln =La, Pr, Nd, Sm, Gd, Tb and Dy)
    • Sebastian Wachowski
    • Iga Szpunar
    • Magnus H. Sorby
    • Aleksandra Mielewczyk-Gryń
    • Maria Balaguer
    • Corneliu Ghica
    • Marian Cosmin Istrate
    • Maria Gazda
    • Anette E. Gunnæs
    • José M Serra
    • Truls Norby
    • Ragnar Strandbakke
    2020 Full text ACTA MATERIALIA

    The structure of BaLnCo2O6-δ (Ln =La, Pr, Nd, Sm, Gd, Tb and Dy) was studied by the means of synchrotron radiation powder X-ray diffraction, neutron powder diffraction and Transmission Electron Microscopy (TEM), while water uptake properties were analysed with the use of thermogravimetry (TG) and water adsorption isotherms. The structure refinement revealed that the dominant phase in all compositions was orthorhombic with an ordering of the A-site cations along the c-axis and ordering of oxygen vacancies along the b-axis, which was also directly evidenced by TEM. It was shown that both unit cell volume and average Co-oxidation state at room temperature decrease linearly with decreasing Ln radius. TG water uptake experiments in humidified N2–O2 gas mixture at 300 °C revealed that among all compositions, only BaLaCo2O6-δ and BaGdCo2O6-δ exhibit significant water uptake. Surface water adsorption studies showed that the α, a normalised parameter reflecting the surface hydrophilicity, mostly independently of Ln radius was close to 0.5, which means that the surface is neither hydrophobic nor hydrophilic. The results indicated that water uptake observed at 300 °C is a bulk process, which cannot be described by standard hydration/hydrogenation reaction and it is related to the layered structure of the perovskite lattice and characteristic to La or Gd being present in the lattice.

  • Structure of the interlayer between Au thin film and Si-substrate: Molecular Dynamics simulations
    • Valeriy Plechystyy
    • Ihor Shtablavyi
    • Szymon Winczewski
    • Kamil Rybacki
    • Stepan Mudry
    • Jarosław Rybicki
    2020 Full text Materials Research Express

    Interaction between 2, 3, 5 and 7 atomic layers of gold and a (111) silicon surface was investigated with the molecular dynamics simulation method. The simulation of the diffusion interaction between gold and silicon in the temperature range 425-925 K has been carried out. The peculiarities of the concentration changes of the interacting components and the atomic density at the boundary of two phases in the direction perpendicular to the crystalline surface were established. By means the formalism of quasi two dimensional partial pair correlation functions the atomic structure of the diffusion region was analyzed. The formation of the alloy of eutectic composition within the gold-silicon interlayer was established. It was shown that the inter-phase mixing in various temperature intervals occurred according to different diffusion mechanisms

  • Students’ soft urban planning skills and local development are the benefits from the Fair of Good Practice. Small cities - big challengesprogramme
    • Karolina Krośnicka
    2020 Full text World Transactions on Engineering and Technology Education

    The urban planner in practice needs soft skills when dealing with public consultations connected to local development plans. To improve the abilities of architecture and urban planning students to discuss solutions and to support the development of local public spaces of small towns in the Pomeranian voivodeship ( province) in Poland, the Fair of Good Practice. Small cities - big challenges programme was developed. It was organised as a series of four projects, each in the form of an urban design studio, and was implemented in the Faculty of Architecture at Gdańsk University of Technology (FA-GUT), between 2016 and 2018. The programme covered urban design topics in two towns of the Pomeranian voivodeship (Rumia and Reda). It was an example of involvement in teaching of different stakeholders connected with urban planning, with an intergenerational exchange of knowledge and support for public participation.

  • STUDY OF CuO AND V2O5 EFFECT ON IR SPECTRA OF POLYCRYSTALLINE BISMUTH NIOBATE
    • Iwona Kuźniarska-Biernacka
    • Agata Lisińska-Czekaj
    • Dionizy Czekaj
    2020 Full text ARCHIVES OF METALLURGY AND MATERIALS

    Bismuth niobate (BiNbO4) ceramics were fabricated by mixed oxide method and sintered by presureless sintering method. BiNbO4 ceramics doped with V2O5 additive in amount 0.125 wt%, 0.250 wt% and 1 wt% of was sintered at T = 910°C whereas BiNbO4 ceramics doped with 2 wt% of CuO additive was sintered at T = 890°C and T = 910°C. It was found that V2O5 additive improved morphology of the ceramic samples. However, the chemical composition of BiNbO4 ceramics in relation to bismuth oxide and niobium oxide manifested a tendency of lack of Bi2O3 component. Absorption bands for the BiNbO4 compound were identified. FTIR band positions associated with NbO6 octahedra suggested that the crystal structure changes after V2O5 incorporation.

  • Study of oxygen electrode reactions on symmetrical porous SrTi0.30Fe0.70O3-δ electrodes on Ce0.8Gd0.2O1.9 electrolyte at 800 °C–500 °C
    • Aleksander Mroziński
    • Sebastian Molin
    • Piotr Jasiński
    2020 Full text ELECTROCHIMICA ACTA

    Iron doped strontium titanates (SrTi1-xFexO3-δ) are an interesting mixed ionic-electronic conductor model used to study basic oxygen reduction/oxidation reactions. In this work, we performed an impedance spectroscopy study on symmetrical porous SrTi0.30Fe0.70O3-δ (STF70) electrodes on a ceriabased electrolyte. The sample was measured in varying oxygen concentration: from 0.3% to 100% in 800 °C - 500 °C temperature range. Low polarisation resistance (e.g. <125 mΩ cm2 at 600 °C in the air) values were obtained, showing an overall high performance of the STF70 electrode. Impedance data analysis was assisted by the distribution of relaxation times method, which allowed an equivalent electrical circuit to be proposed comprising of two resistance/constant phase element sub-circuits connected in series. The medium frequency contribution, with a characteristic frequency of ~2000 Hz at 800 °C in air, originates most probably from possible surface diffusion followed by charge transfer reaction limitation, whereas the lower frequency contribution (characteristic frequency <10 Hz) is due to gas-phase diffusion.

  • Study of railway traffic safety based on the railway track condition monitoring system
    • S Kliuiev
    • Ievgen Medvediev
    • N Khalipova
    2020

    The solution to the problem of monitoring the railway track, as well as potentially dangerous objects and phenomena in the adjacent territories, is determined by the need to implement increased requirements for traffic safety (primarily to the geometric parameters of the devices of a long railway track under construction and functioning load-bearing highways), prevention of technological disasters and large-scale negative effects of natural phenomena on the railways. The continuous process of integrating methods and means of monitoring and preventing emergencies into a single information management system is shown. The possibility of determining a dynamic model of the adverse effect of the train on the track and the most unfavorable for the track train and traction parameters, which must be avoided when forming trains in this section, is established. Three key factors are formulated, the use of which will reduce the negative impact on the track from trains. The concept of information technology improvement of the monitoring system for potentially dangerous sections of the railway on the basis of new innovative technologies has been developed.

  • Study of the Effect of Filling Thermoplastic Medical Polyurethane with PVA, PLA or Diatomite on the Relaxation Times Distributions of 1H NMR
    • Justyna Kucińska-Lipka
    • Nikolay Sinyavsky
    • I. Mershiev I.
    • Józef Haponiuk
    2020 Full text APPLIED MAGNETIC RESONANCE

    In this work, to characterize the mobility of diferent sections of the macromole‑ cules of polyurethane (PUR), polyvinyl alcohol (PVA), and polylactic acid (PLA), as well as the density of crosslinks of the polymer chains when using fllers, we used the distributions of spin–lattice and spin–spin relaxation times for the protons. It is shown that the rigidity of the thermoplastic polymers depends on the sizes of the granules of the diatomite fller, which can embed in the polymer matrix. Conse‑ quently, relaxation times are reduced. If PLA is the fller of PUR, the dynamics of the molecules in the chains and the spin–spin interaction of the protons are afected by the crosslinking of PUR by PLA. An increase in crosslinks density reduces the rate of polymer degradation.

  • Study on applicability of two modal identification techniques in irrelevant cases
    • Agnieszka Tomaszewska
    • Marek Szafrański
    2020 Full text Archives of Civil and Mechanical Engineering

    Study on applicability of two modal identification techniques in irrelevant cases is made in this paper. The following techniques are considered: Peak Picking based on correlation analysis (PP-CA), dedicated for ambient vibrations and Eigensystem Realization Algorithm (ERA), formulated for free decay vibrations investigation. Irrelevant cases are found when analyzed signals are different than recommended to a given technique. The study is conducted on examples of two real structures: masonry tower and steel railway bridge. Both cases are diverse in age, material, excitation and vibrations energy. The signals measured on the tower are suitable for the PP-CA technique (ambient vibrations), while the signals measured on the bridge are suitable for the ERA (free decay vibrations). However, both methods have been applied to both systems. Natural frequencies, mode shapes and damping ratios are identified and the effectiveness of the irrelevant technique is assessed in relation to the results obtained by the relevant method in each case.

  • Study on Methods to Control Interstory Deflections
    • Seyed Mohammad Khatami
    • Hosein Naderpour
    • Seyed Mohammad Nazem Razavi
    • Rui Barros
    • Anna Jakubczyk-Gałczyńska
    • Robert Jankowski
    2020 Full text Geosciences

    One of the possibilities to prevent building pounding between two adjacent structures is to consider appropriate in-between separation distance. Another approach might be focused on controlling the relative displacements during seismic excitations. Although the majority of building codes around the world recommend the use of some equations of various distances between structures to avoid pounding; a lot of reports after earthquakes have obviously shown that safety situation or economic consideration is not always provided due to the collisions between buildings and high cost of land; respectively. The aim of the present paper is to focus the analysis on the properties of structures and conduct an in-depth analysis of available methods to control interstory deflections so as to prevent pounding. For this purpose, a numerical lumped mass model of the five-story building has been considered and its response under different earthquake records has been investigated. Firstly, the influence of the change in structural properties (story stiffness; mass and damping) has been examined. Then the application of tuned mass damper, base isolation and base isolation with rubber bumpers has been considered. The results of comparative analyses clearly indicate that using base isolation, with the addition of bumpers, can be selected as the best method to control building deflections and decrease absolute lateral displacement between two buildings so as to prevent their pounding during earthquakes.

  • Study on Polymer Elements for Mitigation of Earthquake-Induced Pounding Between Buildings in Complex Arrangements
    • Barbara Sołtysik
    • Tomasz Falborski
    • Robert Jankowski
    2020

    Pounding between neighboring structures during seismic events has been revealed as one of the most commonly observed reasons for severe damage or even total collapse of the adjacent buildings. Therefore, pounding effects have recently become an issue of great interest of many numerical and experimental investigations in many earthquake-prone regions of the world. It has also been observed that the differences in dynamic characteristics is the key reason leading to interaction between colliding, insufficiently separated structures. The problem is much more complicated for complex arrangements of structures, for example, in the case of collisions between few structures in a row. A lot of different approaches have been considered to mitigate earthquake-induced structural pounding. One method is based on placing between the structures some viscoelastic elements acting as bumpers. Another one is stiff linking the structures. It allows the forces to be transmitted between buildings and thus eliminate undesired interactions. The aim of this paper is to present the results of experimental research focused on mitigation of pounding between buildings in complex arrangements by using polymer elements installed between structures. In the present study, three steel models characterized by various dynamic properties and different in-between distances were investigated. Additional masses were mounted at the top of each model in order to obtain different dynamic characteristics. The unidirectional shaking table, available at the Gdansk University of Technology (Poland), was employed to conduct this study. Experimental models were mounted to shaking table platform. The results of the study explicitly show that the approach of using polymer elements can be an effective pounding mitigation technique in the case of complex arrangement of buildings. It may partially or fully prevent from damaging collisions between adjacent buildings during seismic events. It also enhances the dynamic response leading to the reduction in lateral vibrations under different strong ground excitations.

  • Study on the Coastline Evolution in Sopot (2008–2018) Based on Landsat Satellite Imagery
    • Mariusz Specht
    • Cezary Specht
    • Oktawia Lewicka
    • Artur Makar
    • Paweł Burdziakowski
    • Paweł Dąbrowski
    2020 Full text Journal of Marine Science and Engineering

    The coastline is the boundary between the water surface in a reservoir or watercourse and the land, which is characterised by high instability and functional diversity. For these reasons, research on coastal monitoring has been conducted for several decades. Currently, satellite images performed with synthetic aperture radars (SARs) are used to determine its course and variability together with high-resolution multispectral imagery from satellites such as IKONOS, QuickBird, and WorldView, or moderate-resolution multispectral images from Landsat satellites. This paper analysed the coastline variability in Sopot (2008–2018) based on Landsat satellite imagery. Furthermore, based on multispectral images obtained, it was determined how the beach surface in Sopot changed. Research has shown that the coastline keeps moving away from the land every year. This was particularly noticeable between 2008 and 2018 when the coastline moved on average 19.1 m towards the Baltic Sea. Moreover, it was observed that the area of the sandy beach in Sopot increased by 14 170.6 m2, which translates into an increase of 24.7% compared to 2008. The probable cause of the continuous coastline shift towards the sea and the increase of the beach surface is the oceanographic phenomenon called tombolo, which occurred in this area as a result of the construction of a yacht marina near the coast.