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Gdańsk University of Technology

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  • Influence of addition of carbon nanotubes on rheological properties of selected liquid lubricants - a computer simulation study
    • Anjali Chopra
    • Szymon Winczewski
    2020 Full text TASK Quarterly

    This work is motivated by the improvement of anti-friction properties of lubricants by addition of CNTs proved experimentally in literature. In particular, a methodology is developed to compute the shear viscosity of liquid lubricants (Propylene Glycol) based on Molecular Dynamics simulation. Non-Equilibrium molecular dynamics (NEMD) approach is used with a reactive force field ReaxFF implemented in LAMMPS. The simulations are performed using the canonical (NVT) ensemble with the so-called SLLOD algorithm. Couette flow is imposed on the system by using Lees-Edwards periodic boundary conditions. Suitable parameters such as simulation time and imposed shear velocity are obtained. Using these parameters, the influence of addition of 27 wt% CNTs to Propylene Glycol on its viscosity is analyzed. Results show that 3.2 million time-steps with a 0.1 fs time-step size is not sufficient for the system to reach equilibrium state for such calculations. With the available computational resources, a shear velocity of 5 × 10−5Å/fs was observed to give viscosity value with approximately 43% error as compared to the experimental value. Moreover, the lubricant exhibited a shear thinning behaviour with increasing shear rates. CNTs enhanced the lubricant’s viscosity by 100-190% depending upon the averaging method used for calculation.

  • Influence of alkaline and oxidative pre-treatment of waste corn cobs on biohydrogen generation efficiency via dark fermentation
    • Karolina Kucharska
    • Piotr Rybarczyk
    • Iwona Hołowacz
    • Donata Konopacka-Łyskawa
    • Edyta Słupek
    • Patrycja Makoś-Chełstowska
    • Hubert Cieśliński
    • Marian Kamiński
    2020 BIOMASS & BIOENERGY

    Stages of waste corn cobs processing leading to the production of biohydrogen via dark fermentation are presented and discussed in this paper. Firstly, the effects of pretreatment conditions i.e. alkaline, alkaline-oxidizing and Fenton oxidizing pre-treatment of lignocellulosic biomass on the removal of lignin were examined. The solid residue obtained in the first stage was subjected to saccharification by means of enzymatic hydrolysis. The composition of enzymatic hydrolysates and fermentation broths were investigated in order to determine the content of sugars as well as phenolic compounds and fermentation broth composition containing organic acids. The dark fermentation process of the obtained hydrolysates was carried using mixed wastewater sludge from the municipal sewage treatment plant. The highest hydrogen production was obtained for alkaline pre-treated hydrolysates. The effects of investigated chemical pre-treatment methods were discussed in terms of the obtained saccharification efficiency and composition of the gas phase formed during the fermentation, and the composition of fermentation broth.

  • INFLUENCE OF CERAMIC COATING ON MECHANICAL PROPERTIES OF STAINLESS STEEL
    • Dionizy Czekaj
    • Agata Lisińska-Czekaj
    • Krzysztof Krzysztofowicz
    2020 Full text ARCHIVES OF METALLURGY AND MATERIALS

    Crystal structure and phase composition of stainless steel substrates (AISI 304 type) was studied and it was found that they adopted the cubic symmetry. The calculated elementary cell parameter for the mayor Fe-Ni phase (weight fraction 99%) was a = 3.593 Å, whereas the mean grain size was <D> = 2932 Å. Morphology of the stainless steel substrate surface was studied with profilometry. Mechanical properties of the stainless steel substrates and stainless steel substrates coated with ceramic layer of barium strontium titanate were studied with microhardness tester. For measurements performed according to the Vickers method the average microhardness was found HV = 189 or HV = 186 for the “in-line” and “mapping” measurement pattern, respectively. The sol-gel method was used to coat the surface of the stainless steel substrate with a thin ceramic layer of the chemical composition Ba0.6Sr0.4TiO3. It was found that the stainless steel substrate covered with sol-gel deposited ceramic coating exhibited the average hardness within the range HV = 217 up to HV = 235 for loading force F = 98 mN and F = 0.98 N, respectively. The Knopp method was also used and it was found that the stainless steel substrate with Ba0.6Sr0.4TiO3 coating exhibited hardness HK = 386.

  • Influence of chemical structure on physicochemical properties and thermal decomposition of the fully bio-based poly(propylene succinate-co-butylene succinate)s
    • Paulina Parcheta
    • Janusz Datta
    2020 Full text POLYMER TESTING

    In this work, two polyesters and four copolyesters were studied. All materials were synthesized to obtain the monomers dedicated for thermoplastic polyurethane elastomers. For this type of PUR, the monomers should characterize by appropriate selected physicochemical properties and macromolecular structure distribution, which depends on synthesis conditions. The study of chemical structure with extensive and knowledgeable analysis of formed macromolecules of synthesized bio-based copolyesters was conducted with the use of FTIR and 1H NMR spectroscopy and MALDI-ToF mass spectrometry. The results allowed to propose the majority of probable chemical structures of macromolecules formed during synthesis. Moreover, the impact of the structure on the thermal stability of the obtained copolyesters was also determined with the use of thermogravimetric analysis. The temperature of the beginning of thermal decomposition equaled even 330oC. Furthermore, the results of DSC-TG/QMS coupled method confirmed that all prepared polyesters degraded by α and β-hydrogen bond scission mechanisms.

  • Influence of Dielectric Overlay Dimensions on Performance of Miniaturized ESPAR Antenna
    • Mateusz Czeleń
    • Mateusz Rzymowski
    • Krzysztof Nyka
    • Łukasz Kulas
    2020 Full text

    In this paper, the influence of dielectric overlay size on miniaturized ESPAR antenna performance has been investigated. The dielectric overlay’s main function is antenna’s size reduction but it can also be used to modify its radiation pattern. This creates the possibility of easy adopting antenna parameters to different applications by swapping used overlay. In particular, the lowering of antenna’s main beam elevation direction has been considered. By using selected alternative overlay one can obtain a 20° lower beam. The design was confirmed by realization and measurements.

  • Influence of Dielectric Overlay Permittivity on Size and Performance of Miniaturized ESPAR Antenna
    • Mateusz Czeleń
    • Mateusz Rzymowski
    • Krzysztof Nyka
    • Łukasz Kulas
    2020 Full text

    In this paper, influence of dielectric overlay permittivity on miniaturized ESPAR antenna parameters is presented. ESPAR antenna is a low-cost and energy-efficient way to implement beam steering capability to a node and improve network performance. The antenna size reduction is obtained by embedding its active and passive elements in ABS based materials of relative permittivity equal to 4, 5.5 and 7.5 in order to achieve network node compact size. Simulation results of three optimized for particular dielectric constant designs are presented and tradeoff between dimensions reduction and performance is discussed. Selected materials and antenna design are dedicated to be fabricated in 3D print technology, so can be easily prototyped.

  • Influence of process of straightening ship hull structure made of 316L stainless steel on corrosion resistance and mechanical properties
    • Jakub Kowalski
    • Łukasz Licznerski
    • Milena Supernak-Marczewska
    • Krzysztof Emilianowicz
    2020 Full text Polish Maritime Research

    The AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries, for architectural elements, and many others. The chemical composition of corrosion-resistant austenitic steels provides them with an austenite structure that is stable in a wide temperature range, under appropriate conditions for heating, soaking, and cooling. 316L steel plate was subjected to a technological treatment of hot straightening with an oxyacetylene torch, which is not commonly used for this type of steel, mainly due to the lack of objective assessment of whether the austenitizing temperature has been achieved and the stability of the heat treatment process is ensured. The single-phase structure of austenite with high corrosion resistance, without precipitation of carbides, steel is obtained by supersaturation in water from 1100°C. The purpose of the presented research was to determine the usefulness of the flame straightening process for a ship structure made of 316L steel.

  • Influence of Selected Warm Mix Asphalt Additives on Cracking Susceptibility of Asphalt Mixtures
    • Marcin Stienss
    • Cezary Szydłowski
    2020 Full text Materials

    Warm mix asphalt (WMA) has been widely accepted as a future asphalt paving technology. Besides clear advantages, there are still some concerns regarding durability and long-term performance of pavements made with this type of asphalt mixtures. One of the most important issues is low temperature behaviour of WMA because certain additives used for temperature reduction can aect bitumen properties. This paper presents the evaluation of low-temperature properties of laboratory-produced asphalt concrete for wearing course with selected WMA additives. One type of bitumen with paving grade 50/70 and fiveWMAadditives of dierent nature (organic, surface tension reducer and combination of both) were used in this study. The production and compaction temperature of mixtures containing WMA additives was 25 C lower in comparison with the temperature of the reference mix. To assess the susceptibility of WMA to low-temperature cracking, Semi-Circular Bending (SCB) and Thermal Stress Restrained Specimen Test (TSRST) were used. Supplementary rating was made by analysing Bending Beam Rheometer (BBR) test results of asphalt binders.

  • Influence of several biodegradable components added to pure and nanosilver-doped PMMA bone cements on its biological and mechanical properties
    • Marcin Wekwejt
    • Marta Michalska-Sionkowska
    • Michał Bartmański
    • Małgorzata Nadolska
    • Krzysztof Łukowicz
    • Anna Pałubicka
    • Anna Maria Osyczka
    • Andrzej Zieliński
    2020 Full text Materials Science & Engineering C-Materials for Biological Applications

    Acrylic bone cements (BC) are wildly used in medicine. Despite favorable mechanical properties, processability and inject capability, BC lack bioactivity. To overcome this, we investigated the effects of selected biodegradable additives to create a partially-degradable BC and also we evaluated its combination with nanosilver (AgNp). We hypothesized that using above strategies it would be possible to obtain bioactive BC. The Cemex was used as the base material, modified at 2.5, 5 or 10 wt% with either cellulose, chitosan, magnesium, polydioxanone or tricalcium-phosphate. The resulted modified BC was examined for surface morphology, wettability, porosity, mechanical and nanomechanical properties and cytocompatibility. The composite BC doped with AgNp was also examined for its release and antibacterial properties. The results showed that it is possible to create modified cement and all studied modifiers increased its porosity. Applying the additives slightly decreased BC wettability and mechanical properties, but the positive effect of the additives was observed in nanomechanical research. The relatively poor cytocompatibility of modified BC was attributed to the unreacted monomer release, except for polydioxanone modification which increased cells viability. Furthermore, all additives facilitated AgNp release and increased BC antibacterial effectiveness.Our present studies suggest the optimal content of biodegradable component for BC is 5 wt%. At this content, an improvement in BC porosity is achieved without significant deterioration of BC physical and mechanical properties. Polydioxanone and cellulose seem to be the most promising additives that improve porosity and antibacterial properties of antibiotic or nanosilver-loaded BC. Partially-degradable BC may be a good strategy to improve their antibacterial effectiveness, but some caution is still required regarding their cytocompatibility.

  • INFLUENCE OF TACK WELDS DISTRIBUTION AND WELDING SEQUENCE ON THE ANGULAR DISTORTION OF TIG WELDED JOINT
    • Jacek Tomków
    • Konrad Sobota
    • Sławomir Krajewsk
    2020 Full text Facta Universitatis-Series Mechanical Engineering

    In this paper the influence of tack welds distribution and welding sequence on angular distortion of the Tungsten Inert Gas (TIG) welded joint was tested. Additionally, the effect of welding current on angular distortion was assessed. For research X2CrTiNb18 (AISI 441) stainless steel (2.5 mm thick) was chosen. During research specimens were prepared with different distributionsof tack welds. Then they were welded by different welding sequenceswith the use of different welding current values. After welding the angular distortion of each specimen was measured by using thecoordinate measuring machine. In the next step specimens were cut. Cross-sections were polished and the metallographic macroscopic testing was conducted to check the geometry of performed welds. Performed experiments allowed determining the optimal tack weld sequence and welding parameters for welding thin stainless steel sheets.

  • Influence of Two-Stage Anodization on Properties of the Oxide Coatings on the Ti–13Nb–13Zr Alloy
    • Agnieszka Ossowska
    • Andrzej Zieliński
    • Jean-marc Olive
    • Andrzej Wojtowicz
    • Piotr Szweda
    2020 Full text Coatings

    The increasing demand for titanium and its alloys used for implants results in need of such innovative surface treatment that may jointly increase corrosion resistance and biocompatibility, and demonstrate antibacterial protection at no cytotoxicity. The purpose of this research was to characterize the effect of two-stage anodization, performed for 30 min in phosphoric acid, at the presence of hydrofluoric acid in the second stage. The scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, glow discharge optical emission spectroscopy, nanoindentation and nano-scratch tests, potentiodynamic corrosion studies, and water contact angle measurements were performed to characterize microstructure, mechanical, chemical and physical properties. The biological examinations were carried out to determine the cytotoxicity and antibacterial effects of oxide coatings. The research results demonstrate that two-stage oxidation affects several features and, in particular, improves mechanical and chemical behavior. The processes influencing the formation and properties of the oxide coating are discussed.

  • Initial Field Validation of Poroelastic Pavement Made with Crumb Rubber, Mineral Aggregate and Highly Polymer-Modified Bitumen
    • Piotr Jaskuła
    • Jerzy Ejsmont
    • Marcin Stienss
    • Grzegorz Ronowski
    • Cezary Szydłowski
    • Beata Świeczko-Żurek
    • Dawid Ryś
    2020 Full text Materials

    Tire/road noise in most driving conditions dominates other sources of traffic noise. One of the most efficient ways of reducing tire/road noise is to use the so-called “low noise pavement”. According to numerous studies, at present, poroelastic road pavement that is composed of rubber and mineral aggregate and polyurethane or bituminous binder gives the best noise reduction up to 12 dB. Unfortunately, there are many problems with making durable poroelastic pavements. This article presents the first results of a project that is executed in Poland and aims at the development of a durable, low noise poroelastic pavement based on polymer-modified asphalt binder called Safe, Eco-friendly POroelastic Road Surface (SEPOR). Two test sectionswere built in 2019 to test the production technology and performance of the SEPOR pavement. It is observed that some of the problems with previous poroelastic materials were mainly eliminated (especially delamination from the base layer and raveling) but noise reduction is a little less than expected (up to 9 dB). Rolling resistance for car tires is acceptable and fire properties (damping of spill fuel fires, toxic gas emission) are very good.

  • Innovation by proxy – clusters as ecosystems facilitating open innovation
    • Marita Mcphillips
    2020 Full text Journal of Entrepreneurship, Management and Innovation

    Open innovation is a concept, whose attributes can be perceived as naturally complementing the proximity-based offer of clusters. The purpose of this paper is to investigate the potential role of clusters as intermediaries of open innovation for cluster members. A literature review and an exploratory study were performed, involving in-depth interviews with experts in the field of innovation and clusters in Poland. This article conceptually links open innovation and clusters, proposes and categorizes roles of clusters as open innovation intermediaries, as well as indicates factors that might affect the successful adoption of this role. Furthermore, it points out that clusters could not only manage and mediate their network of members but also shape and co-create a broader open innovation ecosystem. The findings contribute to a comprehensive understanding of the potential roles of open innovation intermediaries in regard to clusters in the context of transitioning economies. With clusters playing the role of an open innovation intermediary, public support at cluster level could increase the openness to cooperation not only for member companies but all participants in the regional innovation ecosystem.

  • Innovative investment funds and stability of financial systems: Nonparametric study of exchange-traded funds in Europe
    • Adam Marszk
    2020

    The main aim of the paper is investigation of the potential contribution of exchange-trade funds (ETFs) to the instability of the European financial systems. The paper begins with presentation of the key theoretical concepts with regard to ETFs and financial stability. We discuss the key attributes of ETFs as the innovative category of investment funds, their hypothesized impact on the financial stability as well as briefly describe the European ETFs markets, focusing on the between-country differences. Subsequently, we present the results of our study, conducted by applying the selected composite index of the financial stress - Country-Level Index of Financial Stress (CLIFS) provided by the European Central Bank. The core indicator of the development of the ETFs markets is the turnover of the shares of ETFs on the local stock exchange (in order to facilitate comparisons all values are expressed in USD). Time period of the analysis is January 2004 - August 2017 and monthly data are used. Research methods include correlation and nonparametric analysis. Results of our analysis demonstrate that the threats to the European financial systems linked to the expansion of ETFs are minor, above all due to the low size of ETFs markets in most European economies. Moreover, for some ETFs markets with the highest turnover (such as United Kingdom) we identified the positive impact of ETFs to the stability of financial system.

  • Innovative rehabilitation lifts – mechanics in medical devices
    • Anna Czerwińska
    • Wojciech Głąb
    • Mariusz Deja
    • Dawid Zieliński
    2020 Full text Mechanik

    Mechanical devices are now widely used in physiotherapy and other rehabilitation processes. Particular importance is attached to devices enabling easy and effective transport of disabled people. The article presents innovative designs of rehabilitation lifts offered by the Polish manufacturer of lifts and medical accessories, LeviCare company. Moreover, the main assumptions of the research and development project implemented by the company, entitled “Development and testing of an innovative set for the transport and rehabilitation of disabled people on a European scale” are presented. A set of key tests that should be carried out for this type of medical-class devices is indicated.

  • Innovative Turbine Intake Air Cooling Systems and Their Rational Designing
    • Andrii Radchenko
    • Eugeniy Trushliakov
    • Krzysztof Kosowski
    • Dariusz Mikielewicz
    • Mykola Radchenko
    2020 Full text ENERGIES

    The improved methodology of the engine intake air cooling system designing based on the annual effect due to cooling was developed. It involves determining the optimal value of cooling capacity, providing the minimum system sizes at maximum rate of annual effect increment, and its rational value, providing a close to maximum annual effect without system oversizing at the second maximum rate of annual effect increment within the range beyond the first maximum rate. The rational value of design cooling capacity provides practically the maximum annual fuel saving but with the sizes of cooling systems reduced by 15 to 20% due to the correspondingly reduced design cooling capacity of the systems as compared with their values defined by traditional designing focused to cover current peaked short-term thermal loads. The optimal value of cooling capacity providing the minimum sizes of cooling system is very reasonable for applying the energy saving technologies, for instance, based on the thermal storage with accumulating excessive (not consumed) cooling capacities at lowered current thermal loads to cover the peak loads. The application of developed methodology enables revealing the thermal potential for enhancing the efficiency of any combustion engine (gas turbines and engines, internal combustion engines, etc.).

  • Innowacyjna metoda wzmocnienia gruntu za przyczółkiem przy użyciu iniekcji geopolimerowych
    • Anna Banaś
    • Lech Bałachowski
    • Andrzej Kuryłowicz
    • Agnieszka Poteraj-Oleksiak
    2020 Full text Builder

    W obecnych czasach szybki rozwój infrastruktury i nowoczesnych technologii niejednokrotnie narzuca projektantom oraz wykonawcom takie rozwiązania, aby prowadzone roboty budowalne, były jak najmniej uciążliwe dla uczestników ruchu i jak najmniej ingerowały w system komunikacyjny. Dotyczy to zarówno budowy nowych obiektów, jaki i remontu obiektów już istniejących. W niniejszej pracy przedstawiono nowatorską koncepcję remontu wiaduktu w ciągu Drogi Krajowej nr 12 nad torami PKP w miejscowości Podbór. Problemem, który występował podczas eksploatacji obiektu i prowadził do potrzeby pilnej oraz jak najmniej inwazyjnej jego naprawy było nadmierne osiadanie nasypu za przyczółkiem. Pierwszy raz w Polsce wykonano wzmocnienie gruntu za przyczółkiem wiaduktu przy użyciu iniekcji geopolimerowych, które w znaczący sposób skróciło czas ograniczenia w ruchu kołowym, a tym samym i czas samego remontu.

  • Insightful Analysis of Phenomena Arising at the Metal|Polymer Interphase of Au-Ti Based Non-Enzymatic Glucose Sensitive Electrodes Covered by Nafion
    • Adrian Olejnik
    • Jakub Karczewski
    • Anna Dołęga
    • Katarzyna Siuzdak
    • Katarzyna Grochowska
    2020 Full text Coatings

    This paper focuses on the examination of glucose oxidation processes at an electrode material composed of gold nanoparticles embedded in a titanium template. Three dierent conditions were investigated: the chloride content in the electrolyte, its ionic conductivity and the presence of a Nafion coating. The impact of the provided environment on the oxidation reaction was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Two models, namely: chemisorption and incipient hydrous oxide/adatom mediator (IHOAM), were applied to explain the complex voltammetric responses of the electrodes exposed to solutions of varied glucose concentrations.

  • Insights into Compatibilization of Poly(ε-caprolactone)-based Biocomposites with Diisocyanates as Modifiers of Cellulose Fillers
    • Aleksander Hejna
    • Paulina Kosmela
    2020 Full text Mindanao Journal of Science and Technology

    This study aimed to analyze the impact of cellulose fillers’ modification with diisocyanates on the performance of composites based on the poly(ε-caprolactone) (PCL) matrix. Four most commonly used diisocyantes (isophorone, hexamethylene, toluene, and methylene diphenyl) were applied as modifiers of cellulose fillers (5 and 15 wt% per mass of filler). Modified fillers were introduced in the amount of 30 wt% into the PCL matrix. Chemical structure, thermal, static and dynamic mechanical properties of composites were investigated using Fourier transform infrared spectroscopy, differential scanning calorimetry, tensile, hardness and rebound resilience tests, and dynamic mechanical analysis, respectively. Modifications of cellulosic fillers resulted in the decrease of matrix crystallinity and enhancement of interfacial interactions, causing even a two-fold increase of tensile strength and a 25% rise of modulus. These results indicate that through proper adjustment of type and content of diisocyanate modifier, composites’ properties may be engineered.

  • Integrated algorithm for selecting the location and control of energy storage units to improve the voltage level in distribution grids
    • Agata Szultka
    • Seweryn Szultka
    • Stanisław Czapp
    • Zbigniew Lubośny
    • Robert Małkowski
    2020 Full text ENERGIES

    This paper refers to the issue that mainly appears in distribution grids, where renewable energy sources (RES) are widely installed. In such grids, one of the main problems is the coordination of energy production time with demand time, especially if photovoltaic energy sources are present. To face this problem, battery energy storage units (ESU) can be installed. In recent years, more and more attention has been paid to optimizing the use of ESU. This paper contains a simple description of available solutions for the application of ESU as well as an original proposal for selecting the optimal location and control of ESU. The ESU selection method is based on the use of a genetic algorithm and the ESU control method utilizes the fuzzy logic. The combination of the aforementioned methods/algorithms of ESU application is named an integrated algorithm. The performance of the proposed algorithm was validated by multivariate computer simulations with the use of the real low-voltage grid model. The DIgSILENT PowerFactory environment was employed to develop the simulation model of the integrated algorithm. The proposal was utilized to improve the voltage level in the distribution grid and to install the optimal number of ESU. Based on daily load variations for selected load profiles, it was shown that after the ESU application the voltage deviations in the analyzed network were significantly limited. Moreover, the analysis proves that both the location of ESU in the grid and the control of their active and reactive power are important from the point of view of reducing overall costs.

  • Integrated Application of GPR and Ultrasonic Testing in the Diagnostics of a Historical Floor
    • Magdalena Rucka
    • Erwin Wojtczak
    • Monika Zielińska
    2020 Full text Materials

    The paper presents the results of integrated ground penetrating radar (GPR) and ultrasonic testing (UT) measurements conducted on a historical floor in St. Nicholas’ Church, Gdańsk, Poland. The described inspection was the first stage of the technical state assessment of the building. The aim of the study was the detection of underfloor air gaps, which were observed in a few trial pits. The condition of the ground under the floor was determined by localizing other inclusions such as rubble, human remains, brick walls and pipes. To identify the phenomenon of electromagnetic and ultrasonic wave propagation within the air gap, laboratory tests were conducted on physical models consisting of two concrete slabs stacked on top of each other and gradually moved apart to simulate a slot of varying thickness. The conducted research was supported by the numerical models of electromagnetic wave propagation. The obtained results showed that the integration of the GPR and UT methods provided an effective imaging of the floor and the area under it. Ultrasonic testing was proved to be a good technique for identifying air voids, while the GPR method allowed detecting concentrated anomalies and determining the degree of ground homogeneity under the floor.

  • Integrated Experimental and Theoretical Approach for Efficient Design and Synthesis of Gold-Based Double Halide Perovskites
    • Beata Bajorowicz
    • Alicja Mikolajczyk
    • Henry P. Pinto
    • Magdalena Miodyńska
    • Wojciech Lisowski
    • Tomasz Klimczuk
    • Ifat Kaplan-Ashiri
    • Miri Kazes
    • Dan Oron
    • Adriana Zaleska-Medynska
    2020 Full text Journal of Physical Chemistry C

    Applied cutting-edge electronic structure and phonon simulations provide a reliable knowledge about the stability of perovskite structures and their electronic properties, which are crucial for design of effective nanomaterials. Gold is one of the exceptional elements, which can exist both as a monovalent and a trivalent ion in the B site of a double perovskite such as A2BI BIIIX6. However, until now, electronic properties of Cs2AuI AuIIIX6 have not been sufficiently explored and this material was never synthesized using Au1+ and Au3+ precursors in the preparation route. Here, computational simulations combined with an experimental study provide new insight into the properties and synthesis route of Cs2AuI AuIIIX6 (X = Cl, Br, and I) perovskites. First-principles calculations reveal that tetragonal Cs2AuI AuIIIX6 (X = I, Br, Cl) molecules present a band gap of 1.10, 1.15, and 1.40 eV, respectively. Application of novel approaches in the simulations of the VB-XPS for Cs2AuI AuIIICl6 allows replication of the observed spectrum and provides strong evidence of the reliability of the obtained results for the other perovskites Cs2AuI AuIIIX6,X= Br, I. Following theoretical findings, a one-step preparation route of the Cs2AuI AuIIICl6 is developed using a combination of monovalent and trivalent gold precursors at a relatively low temperature. It should be emphasized that this is the first synthesis of this material at low temperatures, allowing for obtaining highly crystalline Cs2Au2Cl6 particles with controlled morphology and without gold impurities. The band gap of synthesized Cs2AuI AuIIICl6 is extended into the NIR spectral range, where most other double perovskites are limited to higher energies, limiting their usage in single junction solar cells or in photocatalysis. The assynthesized Cs2AuI AuIIICl6 exhibits high efficiency in a photocatalytic toluene degradation reaction under visible light irradiation. The developed approach provides information necessary for structure manipulation at the early stage of its synthesis and offers a new and useful guidance for design of novel improved lead-free inorganic halide perovskite with interesting optical and photocatalytic properties.

  • Intencje przedsiębiorcze studentów – analiza międzynarodowa oparta na rozszerzonym modelu Ajzena
    • Julita Wasilczuk
    2020

    Poszukiwanie czynników wpływających na rozpoczęcie działalności gospodarczej doczekało się opisu w wielu publikacjach. Nie ma wątpliwości, że czynnikiem kluczowym w procesie przedsiębiorczym są intencje, a dzięki pracom I. Ajzena wiadomo także, jakie grupy czynników wpływają na intencje. Jednak jego teoria planowanego zachowania wydaje się być niewystarczająca. Celem rozdziału było opracowanie propozycji rozszerzenia teorii Ajzena. Propozycja ta została poddana częściowej analizie statystycznej opartej na wynikach badań przeprowadzonych na grupie ponad 3,5 tys. studentów z pięciu krajów Europy Środkowej oraz Wschodniej. Założono, że na klasyczny model Ajzena wpływa także stosunek do ryzyka. Wyniki wskazują na zróżnicowanie postrzegania korzyści z rozpoczęcia działalności przedsiębiorczej oraz postrzeganą ocenę trudności takiego działania. Studenci z badanych krajów różnili się także podejściem do ryzyka oraz intencjami przedsiębiorczymi.

  • Interaction of 4-nitrothiophenol with low energy electrons: Implications for plasmon mediated reactions
    • Robin Schürmann
    • Thomas F. M. Luxford
    • Ivo S. Vinklárek
    • Jaroslav Kočišek
    • Mateusz Zawadzki
    • Ilko Bald
    2020 Full text JOURNAL OF CHEMICAL PHYSICS

    The reduction of 4-nitrothiophenol (NTP) to 4-4′-dimercaptoazobenzene (DMAB) on laser illuminated noble metal nanoparticles is one of the most widely studied plasmon mediated reactions. The reaction is most likely triggered by a transfer of low energy electrons from the nanoparticle to the adsorbed molecules. Besides the formation of DMAB, dissociative side reactions of NTP have also been observed. Here, we present a crossed electron-molecular beam study of free electron attachment to isolated NTP in the gas-phase. Negative ion yields are recorded as a function of the electron energy, which helps to assess the accessibility of single electron reduction pathways after photon induced electron transfer from nanoparticles. The dominant process observed with isolated NTP is associative electron attachment leading to the formation of the parent anion of NTP. Dissociative electron attachment pathways could be revealed with much lower intensities, leading mainly to the loss of functional groups. The energy gained by one electron reduction of NTP may also enhance the desorption of NTP from nanoparticles. Our supporting experiments with small clusters, then, show that further reaction steps are necessary after electron attachment to produce DMAB on the surfaces.

  • Interactions between bioactive components determine antioxidant, cytotoxic and nutrigenomic activity of cocoa powder extract
    • Monika Baranowska
    • Klaudia Suliborska
    • Vanja Todorović
    • Barbara Kusznierewicz
    • Wojciech Chrzanowski
    • Sladana Sobajić
    • Agnieszka Bartoszek-Pączkowska
    2020 Full text FREE RADICAL BIOLOGY AND MEDICINE

    Numerous studies have shown, rather disappointingly, that isolated bioactive phytochemicals are not as biologically effective as natural plant products. Such a discrepancy may be explained by the concept of food synergy, which was verified in this research for cocoa extract versus its major components with regard to cancer chemoprevention. The evaluation embraced the relationship between redox properties evaluated in cell-free systems with the aid of free radicals scavenging method and differential pulse voltammetry, and redox associated anticarcinogenic activities (cellular antioxidant activity, cytotoxicity, nutrigenomic activity) in human colon adenocarcinoma cell line exposed to either cocoa powder extract or artificial mixtures of cocoa bioactives at matching concentrations. In contrast to expectations, our results showed that the stepwise enrichment with antioxidants caused no gradual increase in the antioxidant activity of the model mixtures; also, these model mixtures did not reach the reducing potential of cocoa in the cell-free systems or cellular model employed. Further, the biological activities examined in colon adenocarcinoma cells did not alter in a stepwise manner that could reflect the gradual changes in composition of bioactive ingredients. In conclusion, the experiments presented here showed that the growing complexity of a mixture of phytochemicals seems to create a new redox bioactive substance rather than enrich the mixture with new activities, characteristic of the compound added. It follows that no simple, predictable relationship can be expected between the chemopreventive potential and the composition of real food items containing a complicated set of non-toxic redox active ingredients. Our observations suggest that the interactions between different bioactive compounds and food matrix components are cooperating factors determining the final bioactivity of foods.

  • Interactions between hydration spheres of two different solutes in solution: The least squares fitting with constraints as a tool to determine water properties in ternary systems
    • Aneta Panuszko
    • Janusz Stangret
    • Bartosz Nowosielski
    • Piotr Bruździak
    2020 Full text JOURNAL OF MOLECULAR LIQUIDS

    Biological systems are complex and the problem of their description lies in mutual interactions between their components. This paper is focused on model experiment-based studies which can reduce these difficulties. The ternary aqueous N-methylacetamide (NMA)–Na2HPO4 system has been studied by means of the FTIR spectroscopy. A novel difference spectra method aimed to extract the spectral contribution of water affected simultaneously by two solutes is proposed. The key improvement is the additional least squares curve fitting procedure with carefully selected constraints which allow obtaining information on the composition of water affected in complex solutions. The fitting parameters are optimized with the Monte Carlo method and the human influence on parameter selection is minimized. The simple method allows determining individual contributions originating in hydration of multiple solution components. FTIR spectra of water in the NMA–Na2HPO4 system gave an insight into the interactions and susceptibility for interactions between solvent and co-solutes or hydrated co-solutes.

  • Interface analysis of compatibilized polymer blends
    • Farnaz Mostafapoor
    • Azadeh Khosravi
    • Abdolhossein Fereidoon
    • Reza Khalili
    • Seyed Hassan Jafari
    • Vahabi Henri
    • Krzysztof Formela
    • Mohammad Saeb
    2020

    This chapter seeks to address the interface location in the compatibilized polymer blends and paves the way for quantitative analysis of interface in terms of interfacial tension and interfacial adhesion to provide support for understanding the relationship between morphology and ultimate properties in the compatibilized polymer blends through the lens of interface. Since understanding and analysis of interfacial phenomena in the compatibilized polymer blends are cumbersome, we started from binary blends and then opened some windows toward quantitative analysis of interface in the compatibilized ternary blends. Then, we give a broad view of interface situation having in mind both physical and chemical interactions to highlight the importance of interface analysis in reactive polymer blends. The contribution of interfacial phenomena to performance of compatibilized ternary blends, as the complex case, is finally discussed for the sake of optimization of properties by interfacial adhesion manipulation

  • Interfacial water controls the process of adsorption of hyperactive antifreeze proteins onto the ice surface
    • Joanna Grabowska
    • Anna Kuffel
    • Jan Zielkiewicz
    2020 Full text JOURNAL OF MOLECULAR LIQUIDS

    A mechanism of interactions between the ice-binding surface of a hyperactive antifreeze protein molecule and the ice surface is proposed, involving the influence of water present between the two surfaces on the behavior of the approaching molecule. It is demonstrated that the interfacial water, even before its full solidification, can act as a factor that pushes away or pulls nearer the protein molecule to ensure its proper positioning. It is possible thanks to the structural properties of interfacial water. These properties include the ability to create high-volume aggregates of water molecules. They can appear near and be anchored to both the ice-binding plane of the anti- freeze molecule and the ice surface. When an AFP approaches the growing face of ice, these high-volume, ordered structures near the ice and near the AFP molecule merge together smoothly, but only if the proper distance be- tween the ice and the AFP is ensured. If this is not the case, the resulting merged structure is deformed from its preferred shape and as a result a force occurs that attempts to correct the positioning of the protein. Only then the crystallization of the merged aggregate can proceed unhampered which results in binding of the AFP molecule onto the ice.

  • Intergranular Corrosion Detection Using Electromagnetic Transducers for Ultrasonic Testing
    • Mateusz Cieślik
    • Kazimierz Darowicki
    2020 Full text ARCHIVES OF METALLURGY AND MATERIALS

    The aim of this paper is to create a research methodology that allows a quick analysis of the structural state of high alloy austenitic steels using non-destructive ultrasonic tests, in contrast to destructive standard methods. Electromagnetic acoustic transducers (EMAT) are used to generate and receive the ultrasonic wave and detect the microstructural changes caused by sample sensitization in elevated temperature, even after 0.5 h in high temperature exposition. Different acoustic response for reference sample and sensitized samples were recorded. In this work, changes in share wave amplitude were measured.

  • Interlaboratory Test to Characterize the Cyclic Behavior of Bituminous Interlayers: An Overview of Testing Equipment and Protocols
    • Francesco Canestrari
    • Thomas Attia
    • Hervé Di Benedetto
    • Andrea Graziani
    • Piotr Jaskuła
    • Youngsoo Richard Kim
    • Maciej Maliszewski
    • Jorge C. Pais
    • Christophe Petit
    • Christiane Raab
    • Davide Ragni
    • Dawid Ryś
    • Cesare Sangiorgi
    • Cédric Sauzéat
    • Adam Zofka
    2020 Full text

    The performance assessment of multi-layered pavements strongly depends on the mechanical behavior of the interface between bituminous layers. So far, comprehensive studies have been carried out mainly using quasi-static laboratory tests focusing on the interlayer shear strength at failure. However, it is generally recognized that cyclic shear testing will lead to the determination of parameters which are more closely linked to the performance of pavements under traffic loading than the quasi-static shear tests. This paper outlines the research work that has been carried out within the Task Group 3 “Pavement multilayer system” of the RILEM TC 272-PIM. The activities focused on cyclic shear testing of interfaces in bituminous pavements involve an interlaboratory test with nine participating laboratories. The interface behavior was investigated through both direct shear and torque tests on double-layered specimens extracted from lab compacted slabs prepared by one of the laboratories. The different testing equipment and protocols used by the participating laboratories are presented, highlighting the variety of geometries, loading modes, and testing parameters.

  • International architectural - urban - landscape design workshops to strengthen students’ education, capabilities and mobility
    • Aleksandra Sas-Bojarska
    • Magdalena Rembeza
    2020 Full text World Transactions on Engineering and Technology Education

    Five international architectural/urban/landscape workshops in Poland and Portugal between 2011 and 2015 are discussed in this article. The general aims of the workshops were to plan to connect divided city spaces, to harmonise them and make them attractive for different uses. The main task was to create in multicultural groups of students the vision of sustainable development in the context of architecture, urban and landscape design, with special attention to the environmental, social, spatial and transportation issues. The case studies could be good examples of academic co-operation that supports the mobility of students and academic teachers. Both groups benefited from the exchange of views, new ideas and trends, co-operation and the building of professional and personal relationships.

  • Interpolation methods in GPR tomographic imaging of linear and volume anomalies for cultural heritage diagnostics
    • Magdalena Rucka
    • Erwin Wojtczak
    • Monika Zielińska
    2020 Full text MEASUREMENT

    This paper presents results of a ground penetrating radar (GPR) survey conducted in St. Joseph’s Church in Gdańsk, Poland. The aim of the study was to produce tomographic imaging of a renovated floor as well as the objects buried under the floor to detect linear and volume inclusions. The assumed track spacing was meaningfully greater than the single signal spacing in each track, which induced the need for interpolation methods to estimate signal values in the areas beyond the trace lines. Various interpolation techniques were used to prepare the tomography maps. GPR time slices allowed the identification of reinforcing meshes, underfloor heating system elements and the foundations of entrances to crypts. The results obtained were compared to the exact images acquired in a dense regular grid to evaluate the efficiency of the applied interpolation methods and to verify the possibility of conducting GPR surveys with coarse track spacing.

  • Interpretation and modeling of emotions in the management of autonomous robots using a control paradigm based on a scheduling variable
    • Zdzisław Kowalczuk
    • Michał Czubenko
    • Tomasz Merta
    2020 Full text ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE

    The paper presents a technical introduction to psychological theories of emotions. It highlights a usable ideaimplemented in a number of recently developed computational systems of emotions, and the hypothesis thatemotion can play the role of a scheduling variable in controlling autonomous robots. In the main part ofthis study, we outline our own computational system of emotion – xEmotion – designed as a key structuralelement in the developed target device, being an Intelligent System of Decision-making (ISD) for autonomousand robotic units.The ISD system has a cognitive architecture based on the principles of human psychology. The mainpurpose of building such a system is to prepare a framework for autonomous units used in system engineering(Kowalczuk and Czubenko, 2011; Czubenko et al., 2015). In particular, ISD is based on the concepts ofcognitivepsychology(in information processing) andmotivation theory, which includes the system ofneeds(for decision-making). The xEmotion subsystem, however, focuses on modeling an alternative approach based on emotion.The xEmotion implementation covers aspects of somatic, appraisal and evolutionary theories of emotions usingfuzzy sets.In this article, we also illustrate the core emotional behavior of the ISD system using simulation. Thefirst application is a user interface for identifying emotions and predicting human behavior. The second is aneSailor simulation, which illustrates the possible behavior of the xEmotion subsystem. The last is an xDriversimulation experiment, which is to prove the validity of the concept of using emotion-based systems, accordingto the SVC principle. In summary, we also discuss other possible applications of the xEmotion system.

  • Interrelations between Travel Patterns and Urban Spatial Structure of the Largest Russian Cities
    • Ekaterina Saveleva
    2020

    The study presented within this dissertation involves the analysis of the relationship between urban spatial structure and travel patterns in the largest Russian cities. It is an empirical investigation of how the spatial structure, formed during the Soviet and post-Soviet periods, affects the travel patterns in the largest cities of contemporary Russia. It aims to determine what measures, both urban structure and transportation related, are suitable for such urban form to introduce most sustainable mobility patterns. The dissertation examines in detail how urban form and travel are interlinked, and how mobility patterns are created through many factors, not the last of which is the built environment. It provides a review of theoretical model of interaction between urban form and travel patterns followed by the empirical analysis of the link between urban spatial structure and travel patterns performed on a sample of the 13 largest Russian cities. The result of the GIS-based spatial analysis of the Russian cities‘ urban morphology comes in the form of quantitative dataset of various urban form characteristics, which are further used for the exploration of the interrelation between them and travel patterns in the largest Russian cities. Building on the findings regarding travel and urban form relationship in the largest Russian cities, the dissertation proposes both general directions for the development of cities with Soviet past and particular recommendations for the largest Russian cities, taking into account the current mobility situation, the specificities of their urban structure and the influence it has on the travel patterns.

  • Invasive Assessment of the Myocardial Microcirculation during Beating Heart Coronary Artery Bypass Grafting
    • Mariusz Kaszubowski
    • Marcin Hellmann
    2020 Full text Journal of Clinical Medicine

    Coronary artery bypass grafting may be associated with several cardiac complications, including ischemia, acute myocardial infarction, arrhythmias, or hemodynamic instability. Accumulating evidence suggests that well-developed coronary collateral circulation may protect against adverse effects, including myocardial ischemia. Assessment of myocardial microvascular perfusion is, therefore, of great clinical interest in beating heart surgery. In this paper, myocardial microvascular perfusion is continuously assessed on the beating heart using laser Doppler flowmetry in consecutive patients who underwent coronary artery bypass grafting procedures. No significant (p = 0.110) differences were found between the averaged perfusion signal (n = 42) at the baseline, during artery occlusion, or after reperfusion (732.4 ± 148.0 vs. 711.4 ± 144.1 vs. 737.0 ± 141.2, respectively). In contrast, significantly different (p < 0.001) mean perfusion signals (n = 12) were found (805.4 ± 200.1 vs. 577.2 ± 212.8 vs. 649.3 ± 220.8) in a subset of patients who presented with hemodynamic instability and myocardial ischemia. Additionally, a strong positive correlation between the plasma levels of high-sensitivity troponin I and perfusion decrease level after artery occlusion was found (r = 0.854, p < 0.001). This study argues that myocardial microvascular perfusion remains constant during coronary artery bypass grafting on the beating heart in advanced coronary artery disease. This phenomenon is most likely due to an extensive coronary collateral circulation.

  • Inverse Analysis as a Key Element of Safety Assessment under the Snow Load For The Large Suspension Roofs Structure
    • Krzysztof Żółtowski
    • Michał Drawc
    2020 Full text Archives of Civil Engineering

    The paper presents a concept and realization of monitoring system for the Silesian Stadium in Chorzow. The idea of the system lies in fusion of structure monitoring with a calibrated numerical FEM model [1]. The inverse problem is solved. On the base of measured selected displacements, the numerical FEM model of the structure combined with iterative method, develops the current snow load distribution. Knowing the load, we can calculate the forces and stresses in each element of the structure and thanks to this we can determine the safety thresholds and asses the owner. Test results and conclusions are presented

  • Inverse shadowing and related measures
    • Sergey Kryzhevich
    • Sergei Pilyugin
    2020 Full text Science China-Mathematics

    We study various weaker forms of the inverse shadowing property for discrete dynamical systems on a smooth compact manifold. First, we introduce the so-called ergodic inverse shadowing property (Birkhoff averages of continuous functions along an exact trajectory and the approximating one are close). We demonstrate that this property implies the continuity of the set of invariant measures in the Hausdorff metric. We show that the class of systems with ergodic inverse shadowing is quite broad; it includes all diffeomorphisms with hyperbolic nonwandering sets. Second, we study the so-called individual inverse shadowing (any exact trajectory can be traced by approximate ones, but this shadowing is not uniform with respect to the initial point of the trajectory). We demonstrate that this property is closely related to structural stability and Ω-stability of diffeomorphisms.

  • Investigating Analytics Dashboards’ Support for the Value-based Healthcare Delivery Model
    • Mona Isazad Mashinchi
    • Adegboyega Ojo
    • J. Francis Sullivan
    2020 Full text

    Improving the value of care is one of the essential aspects of Value-Based Healthcare (VBHC) model today. VBHC is a new HC delivery model which is centered on patient health outcomes and improvements. There is anecdotal evidence that the use of decision aid tools like dashboards can play a significant role in the successful implementation of VBHC models. However, there has been little or no systematic studies and reviews to establish the extent to which analytics dashboards are used to support patient care in a VBHC delivery context. This paper bridges this knowledge gap through a systematic review of the existing literature on dashboards in the HC domain. Our study reveals dashboard capabilities as an enabling tool for value improvements and provides insight into the design of dashboards. This study concludes by highlighting a few gaps, question, and need for research in the future.

  • Investigating Feature Spaces for Isolated Word Recognition
    • Povilas Treigys
    • Grazina Korvel
    • Gintautas Tamulevicius
    • Jolita Bernataviciene
    • Bożena Kostek
    2020

    The study addresses the issues related to the appropriateness of a two-dimensional representation of speech signal for speech recognition tasks based on deep learning techniques. The approach combines Convolutional Neural Networks (CNNs) and time-frequency signal representation converted to the investigated feature spaces. In particular, waveforms and fractal dimension features of the signal were chosen for the time domain, and three feature spaces were investigated for the frequency domain, namely: Linear Prediction Coefficient (LPC) spectrum, Hartley spectrum, and cochleagram. Due to the fact that deep learning requires an adequate training set size of the corpus and its content may significantly influence the outcome, thus for the data augmentation purpose, the created dataset was extended with mixes of the speech signal with noise with various SNRs (Signal-to-Noise Ratio). In order to evaluate the applicability of the implemented feature spaces for isolated word recognition task, three experiments were conducted, i.e., 10-, 70-, and 111-word cases were analyzed.

  • Investigating the Impact of Curing System on Structure-Property Relationship of Natural Rubber Modified with Brewery By-Product and Ground Tire Rubber
    • Łukasz Zedler
    • Xavier Colom
    • Javier Cañavate
    • Mohammad Saeb
    • Józef Haponiuk
    • Krzysztof Formela
    2020 Full text Polymers

    The application of wastes as a filler/reinforcement phase in polymers is a new strategy to modify the performance properties and reduce the price of biocomposites. The use of these fillers, coming from agricultural waste (cellulose/lignocellulose-based fillers) and waste rubbers, constitutes a method for the management of post-consumer waste. In this paper, highly-filled biocomposites based on natural rubber (NR) and ground tire rubber (GTR)/brewers’ spent grain (BSG) hybrid reinforcements, were prepared using two different curing systems: (i) sulfur-based and (ii) dicumyl peroxide (DCP). The influence of the amount of fillers (in 100/0, 50/50, and 0/100 ratios in parts per hundred of rubber) and type of curing system on the final properties of biocomposites was evaluated by the oscillating disc rheometer, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, swelling behavior, tensile testing, and impedance tube measurements. The results show, that the scorch time and the optimum curing time values of sulfur cured biocomposites are affected by the change of the hybrid filler ratio while using the DCP curing system, and the obtained values do not show significant variations. The results conclude that the biocomposites cured with sulfur have better physico-mechanical and acoustic absorption, and that the type of curing system does not influence their thermal stability. The overall analysis indicates that the difference in final properties of highly filled biocomposites cured with two different systems is mainly affected by the: (i) cross-linking efficiency, (ii) partial absorption and reactions between fillers and used additives, and (iii) affinity of additives to applied fillers.

  • Investigation into MPI All-Reduce Performance in a Distributed Cluster with Consideration of Imbalanced Process Arrival Patterns
    • Jerzy Proficz
    • Piotr Sumionka
    • Jarosław Skomiał
    • Marcin Semeniuk
    • Karol Niedzielewski
    • Maciej Walczak
    2020 Full text Advances in Intelligent Systems and Computing

    The paper presents an evaluation of all-reduce collective MPI algorithms for an environment based on a geographically-distributed compute cluster. The testbed was split into two sites: CI TASK in Gdansk University of Technology and ICM in University of Warsaw, located about 300 km from each other, both connected by a fast optical fiber Ethernet-based 100 Gbps network (900 km part of the PIONIER backbone). Each site hosted a set of 10~compute nodes interconnected locally by the InfiniBand switches with the traffic forwarded by specialized hardware: IBEX G40 - QDR InfiniBand RDMA based Extension Platform. A set of six all-reduce algorithms, consisting of two ring-based (including a PAP-aware pre-reduced ring), two binomial-tree based and two hierarchical ones, was tested for balanced and imbalanced process arrival patterns (PAPs). The results showed high and stable bandwidth with large data transmission latency of the branch connecting the remote sites (about 13 ms in comparison to 10 us locally), and for the tested algorithms there was an advantage of hierarchical approach, and then binomial tree. Finally, we also observed some performance increase in PAP-aware solution in comparison to its regular counterpart. The main conclusion is that for the distributed cluster environment with imbalanced PAPs, there is a need for designing new hierarchical algorithms with PAP-aware support.

  • Investigation of Parallel Data Processing Using Hybrid High Performance CPU + GPU Systems and CUDA Streams
    • Paweł Czarnul
    2020 Full text COMPUTING AND INFORMATICS

    The paper investigates parallel data processing in a hybrid CPU+GPU(s) system using multiple CUDA streams for overlapping communication and computations. This is crucial for efficient processing of data, in particular incoming data stream processing that would naturally be forwarded using multiple CUDA streams to GPUs. Performance is evaluated for various compute time to host-device communication time ratios, numbers of CUDA streams, for various numbers of threads managing computations on GPUs. Tests also reveal benefits of using CUDA MPS for overlapping communication and computations when using multiple processes. Furthermore, using standard memory allocation on a GPU and Unified Memory versions are compared, the latter including programmer added prefetching. Performance of a hybrid CPU+GPU version as well as scaling across multiple GPUs are demonstrated showing good speed-ups of the approach. Finally, the performance per power consumption of selected configurations are presented for various numbers of streams and various relative performances of GPUs and CPUs.

  • Investigation of praseodymium and samarium co-doped ceria as an anode catalyst for DIR-SOFC fueled by biogas
    • Beata Bochentyn
    • Piotr Błaszczak
    • Maria Gazda
    • A. Fuerte
    • S. F. Wang
    • Piotr Jasiński
    2020 Full text INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    The Pr and Sm co-doped ceria (with up to 20 mol.% of dopants) compounds were examined as catalytic layers on the surface of SOFC anode directly fed by biogas to increase a lifetime and the efficiency of commercially available DIR-SOFC without the usage of an external reformer. The XRD, SEM and EDX methods were used to investigate the structural properties and the composition of fabricated materials. Furthermore, the electrical properties of SOFCs with catalytic layers deposited on the Ni-YSZ anode were examined by a current density-time and current density-voltage dependence measurements in hydrogen (24h) and biogas (90h). Composition of the outlet gasses was in situ analysed by the FTIR-based unit. It has been found out that Ce0.9Sm0.1O2-δ and Ce0.8Pr0.05Sm0.15O2-δ catalytic layers show the highest stability over time and thus are the most attractive candidates as catalytic materials, in comparison with other investigated lanthanide-doped ceria, enhancing direct internal reforming of biogas in SOFCs.

  • Investigation of rotational state-changing collisions of C2N− ions with helium
    • Jan Franz
    • Francesco Antonio Gianturco
    2020

    The cross sections for rotational inelastic collisions between atoms and a molecular anion can be very large, if the anion has a dipole moment. This makes molecular anions very efficient in cooling atomic gases. We address rotational inelastic collisions of Helium atoms with the molecular anion C2N–. Here we present preliminary calculations of the potential energy surface.

  • Investigation of the Dynamism of Nanosized SOA Particle Formation in Indoor Air by a Scanning Mobility Particle Sizer and Proton-Transfer-Reaction Mass Spectrometry
    • Klaudia Pytel
    • Renata Marcinkowska
    • Bożena Zabiegała
    2020 Full text MOLECULES

    Terpenes are VOCs of particular importance, since they are emitted from a wide range of indoor sources and are considered to be precursors of Secondary Organic Aerosol (SOA) formation. It has been proven that SOA particles, especially nanosized ones, pose a threat to human health. In this research, experiments with the application of an environmental chamber and real-time measurement techniques were carried out to investigate in a complimentary way the formation of monoterpene oxidation products and nanosized SOA particles initiated by monoterpene ozonolysis. Proton-Transfer-Reaction Mass Spectrometry with a Time-Of-Flight analyzer (PTR-TOF-MS) and a Scanning Mobility Particle Sizer (SMPS) were applied to determine in real time the dynamism of the formation of the corresponding terpene ozonolysis products and submicron SOA particles. Results proved that firstly, oxidation products were formed, and then, they underwent nucleation and condensation, forming particles whose diameters grew with time. The oxidation products formed were different depending on the type of terpenes applied. The comparison of the results obtained during the experiments with gaseous standard mixtures and real samples commonly present and used in indoor air revealed that the diversified chemical composition of the emission source had implications for both the particle formation initiated by the oxidation of essential oil components and the chemical reactions occurring via the oxidation process. With the instrumentation utilized, the concentration changes at the level of a few ppbv could be monitored

  • Investigation on the Sources and Impact of Trace Elements in the Annual Snowpack and the Firn in the Hansbreen (Southwest Spitsbergen)
    • Andrea Spolaor
    • Beatrice Moroni
    • Bartłomiej Luks
    • Adam Nawrot
    • Marco Roman
    • Catherine Larose
    • Łukasz Stachnik
    • Federica Bruschi
    • Krystyna Kozioł
    • Filip Pawlak
    • Clara Turetta
    • Elena Barbaro
    • Jean-Charles Gallet
    • David Cappelletti
    2020 Full text Frontiers in Earth Science

    We present a thorough evaluation of the water soluble fraction of the trace element composition (Ca, Sr, Mg, Na, K, Li, B, Rb, U, Ni, Co, As, Cs, Cd, Mo, Se, Eu, Ba, V, Ge, Ga, Cr, Cr, P, Ti, Mn, Zr, Ce, Zn, Fe, Gd, Y, Pb, Bi, Yb, Al, Nb, Er, Nd, Dy, Sm, Ho, Th, La, Lu, Tm, Pr, Tb, Fe, In, Tl) and their fluxes in the annual snowpack and the firn of the Hansbreen (a tidewater glacier terminating in the Hornsund fjord, southwest Spitsbergen). The trace element samples were obtained from a 3 m deep snow pit dug at the plateau of the glacier (450 m a.s.l.), and from a 2 m deep firn core collected from the bottom of the snow pit. The comparison of elemental fluxes and enrichment factors allowed us to constrain specific summer and wintertime deposition patterns of water soluble trace elements in the southern part of the Svalbard archipelago. Our results suggest that the chemical composition of the Hansbreen (and likely other glaciers where the summit is close to the equilibrium line) is mainly affected by summertime deposition of trace elements from local sources and some volatile elements, which may be transported into the Arctic when polar vortex is weak. The melting of the annual snowpack seems to have a minor influence on the overall chemical signature of the glacier ice.

  • Investigations of the Methods of Time Delay Measurement of Stochastic Signals Using Cross-correlation with the Hilbert Transform
    • Robert Hanus
    • Marcin Zych
    • Rafał Chorzępa
    • Anna Golijanek-Jędrzejczyk
    2020 Full text

    The article presents the results of simulation studies of four methods of estimating time delay for random signals using cross-correlation with the Hilbert Transform. Selected models of mutually delayed stochastic signals were used in the simulations, corresponding to the signals obtained from scintillation detectors in radioisotope measurements of liquid-gas two-phase flow. Standard deviations of the values of the individual functions were designated and compared, along with standard deviations of time delay estimates determined on their basis. The obtained results were compared with the results for classic cross-correlation function (CCF). It was found that for the analysed range of the signal-to-noise ratio (SNR): 0.2 ≤ SNR ≤ 5, the lowest values of standard deviation of time delay estimates were obtained for the CCFHT function (cross-correlation with the Hilbert Transform of the delayed signal).

  • Investigations of the Working Process in a Dual-Fuel Low-Emission Combustion Chamber for an FPSO Gas Turbine Engine
    • Serhiy Serbin
    • Badri Diasamidze
    • Marek Dzida
    2020 Full text Polish Maritime Research

    This investigation is devoted to an analysis of the working process in a dual-fuel low-emission combustion chamber for a floating vessel’s gas turbine. The low-emission gas turbine combustion chamber with partial pre-mixing of fuel and air inside the outer and inner radial-axial swirlers was chosen as the object of research. When modelling processes in a dual-flow low-emission gas turbine combustion chamber, a generalized method is used, based on the numerical solution of the system of conservation and transport equations for a multi-component chemically reactive turbulent system, taking into consideration nitrogen oxides formation. The Eddy-Dissipation-Concept model, which incorporates Arrhenius chemical kinetics in a turbulent flame, and the Discrete Phase Model describing the interfacial interaction are used in the investigation. The obtained results confirmed the possibility of organizing efficient combustion of distillate liquid fuel in a low-emission gas turbine combustion chamber operating on the principle of partial preliminary formation of a fuel-air mixture. Comparison of four methods of liquid fuel supply to the channels of radial-axial swirlers (centrifugal, axial, combined, and radial) revealed the advantages of the radial supply method, which are manifested in a decrease in the overall temperature field non-uniformity at the outlet and a decrease in nitrogen oxides emissions. The calculated concentrations of nitrogen oxides and carbon monoxide at the flame tube outlet for the radial method of fuel supply are 32 and 9.1 ppm, respectively. The results can be useful for further modification and improvement of the characteristics of dual-fuel gas turbine combustion chambers operating with both gaseous and liquid fuels.

  • Ion recognition properties of new pyridine-2,6-dicarboxamide bearing propeller-like pendant residues: multi-spectroscopic approach
    • Ewa Wagner-Wysiecka
    • Natalia Łukasik
    • Andrzej Okuniewski
    • Błażej Galiński
    2020 Full text MONATSHEFTE FUR CHEMIE

    The synthesis and ion binding properties of new amide derived from propeller-like tris(2-pyridyl)amine and 2,6-pyridinedicarboxylic acid chloride were described. Amide binds divalent metal cations: copper(II), nickel(II), zinc(II), and lead(II) in acetonitrile. In acetonitrile:water mixture (9:1 v/v) amide interacts only with copper(II) and nickel(II) cations forming complexes of 1:1 stoichiometry. It was found that the introduction of bulky, nitrogen donor atom bearing pendant groups can influence coordination mode of pyridine-2,6-dicarboxamides. The probable model of ligand-ion interactions is proposed on the basis of 1H NMR and FT-IR spectroscopy.

  • Ionic liquids in the microextraction techniques: the influence of ILs structure and properties
    • Kateryna Yavir
    • Karolina Konieczna
    • Łukasz Marcinkowski
    • Adam Kloskowski
    2020 TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    Ionic liquids (ILs) are composed entirely of ions thus they possess unique properties, including negligible volatility, a liquid state in a broad range of temperatures and ability to change them depending on the chosen type of anion and cation, which make ILs unique and useful for many applications in sample preparation techniques. A deeper understanding of the nature of ILs and the impact of their structure on their parameters is the key to the success of conscious use of them as potential sorption media for a given purpose. This review describes the key physical and chemical properties of ILs in the context of their importance in sample preparation techniques. The review also presents selected combinations of ILs with solid-phase microextraction, SPME; single drop microextraction, SDME; dispersive liquid-liquid microextraction, DLLME, in terms of the role of ILs properties in a given technique.