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  • The Impact of Lexicon Adaptation on the Emotion Mining From Software Engineering Artifacts
    • Michał Wróbel
    2020 Pełny tekst IEEE Access

    Sentiment analysis and emotion mining techniques are increasingly being used in the field of software engineering. However, the experiments conducted so far have not yielded high accuracy results. Researchers indicate a lack of adaptation of the methods of emotion mining to the specific context of the domain as the main cause of this situation. The article describes research aimed at examining whether the adaptation of the lexicon with emotional intensity of words in the context of software engineering improves the reliability of sentiment analysis. For this purpose, a new lexicon is developed in which words are evaluated as if they were used in the field of software engineering. A comparative experiment of emotion mining based on a generic and a software engineering specific lexicon does not reveal any significant differences in the results.

  • The Impact of Material Selection on Durability of Exhaust Valve Faces of a Ship Engine – A Case Study
    • Hanna Smoleńska
    • Włodzimierz Kończewicz
    • Sylwia Bazychowska
    2020 Pełny tekst Advances in Science and Technology Research Journal

    wo alloys were used in order to extend the service life of marine engine exhaust valve head. Layers of cobalt base alloys were made of the powders with with chemical composition as follow: the layer marked L12; C-1,55%; Si-1,21%; Cr-29,7%; W-9%; Ni-2%; Mo<0,01%; Fe-1,7%; Co-54,83% and the layer marked N; C-1,45%; Co-38,9%; Cr-24,13%; Ni-10,43%; W-8,75%; Fe-7,64%; Mo-7,56%; Si-2,59%. Base metal was valve steel after heat treatment. It was consisted of: C-0,374%; Cr-9,34%; Mn-0,402%; Ni-0,344%; Si-2,46%; Mo-0,822%; P0,0162%; S-0,001%. Layers on the valve faces were produced by laser cladding using the HPDL ROFIN DL020 laser. Grinding treatment is a very popular form of regeneration of seat and valve plug adhesions. Properly performed grinding operation ensures dimensional and shape accuracy of the surface from 7 to 5 accuracy class and surface roughness Ra not less than 0,16 μm, depending on the object and method of grinding. The 75H and 150S types are a significantly simplified form of valve plug face grinders. Finishing treatment was carried out with a Chris-Marine AB75H sander on a sanding stand equipped with a compressed air system - the stand was designed by the author. The sander has been set up to the surface of the valve stem so that the grinding angle of the valve faces is 30°+10°. A flat grinding wheel T1CRA54–K was used for machining. The plunge feed was g = 0,01 mm/rev. The thickness of the welded layer after grinding was 1,2 mm. Both valves were installed in the ship's engine and were used in real life. After 2000 hours of operation, the valve marked N was damaged. The valve marked L12 showed no damage and was in operation for the next 1000 hours.

  • The Impact of Micro-Sources on Voltage Distortions in a Power Grid
    • Magdalena Grzymkowska
    • Jacek Klucznik
    2020 Pełny tekst Acta Energetica

    The increase in the number of photovoltaic (PV) systems integrated with low voltage (LV) grids has led to a great need to analyse the impact of these systems on the quality of electricity and the reliability of its supply. This paper presents and compares the energy quality requirements imposed by various countries on photovoltaic plants. Then, based on real object tests and simulation in DIgSILENT PowerFactory, the impact has been identified of insolation on the generation output, range of harmonic emissions, changes in voltage levels, and total harmonic distortion (THD) in current and voltage. The results depended on the micro-source power and location, and the grid load.

  • The Impact of Spatiotemporal Changes in Land Development (1984–2019) on the Increase in the Runoff Coefficient in Erbil, Kurdistan Region of Iraq
    • Andam Mustafa
    • Michał Szydłowski
    2020 Pełny tekst Remote Sensing

    Nowadays, geospatial techniques are a popular approach for estimating urban flash floods by considering spatiotemporal changes in urban development. In this study, we investigated the impact of Land Use/Land Cover (LULC) changes on the hydrological response of the Erbil basin in the Kurdistan Region of Iraq (KRI). In the studied area, the LULC changes were calculated for 1984, 1994, 2004, 2014 and 2019 using the Digital Elevation Model (DEM) and satellite images. The analysis of LULC changes showed that the change between 1984 and 2004 was slower than that between 2004 and 2019. The LULC analysis revealed a 444.4% growth in built-up areas, with a 60.4% decrease in agricultural land between 1984 and 2019. The influence of LULC on urban floods caused by different urbanization scenarios was ascertained using the HEC-GeoHMS and HEC-HMS models. Over 35 years, there was a 15% increase in the peak discharge of outflow, from 392.2 m3/sec in 1984 to 450 m3/sec in 2014, as well as the runoff volume for a precipitation probability distribution of 10%, which increased from 27.4 mm in 1984 to 30.9 mm in 2014. Overall, the probability of flash floods increased in the center of the city due to the large expansion of built-up areas.

  • The impact of the AC922 Architecture on Performance of Deep Neural Network Training
    • Paweł Rościszewski
    • Michał Iwański
    • Paweł Czarnul
    2020

    Practical deep learning applications require more and more computing power. New computing architectures emerge, specifically designed for the artificial intelligence applications, including the IBM Power System AC922. In this paper we confront an AC922 (8335-GTG) server equipped with 4 NVIDIA Volta V100 GPUs with selected deep neural network training applications, including four convolutional and one recurrent model. We report performance results depending on batch sizes and GPU selection and compare them with the results from another contemporary workstation based on the same set of GPUs – NVIDIA® DGX Station ™ . The results show that the AC922 performs better in all tested configurations, achieving improvements up to 10.3%. Profiling indicates that the improvement is due to the efficient I/O pipeline. The performance differences depend on the specific model, rather than on the model class (RNN/CNN). Both systems offer good scalability up to 4 GPUs. In certain cases there is a significant difference in performance depending on exactly which GPUs are used for computations.

  • The Impact Of The Selected Parameters Of Fdm Manufacturing Technology On Tribological Performance Of Abs–Steel Pair Under Dry Friction
    • Katarzyna Suwińska
    • Jacek Łubiński
    2020 Pełny tekst TRIBOLOGIA

    The paper presents the result of tribological test of ABS and steel samples sliding under dry friction. Polymeric samples were manufactured of ABS material using FDM technology. Testing was carried out in unidirectional sliding in a ring-on-flat contact in a PT-3 tribometer. The scope of tested parameters included volumetric and mass wear, the friction coefficient, and polymeric specimen temperature. Polymeric specimens used in the study were manufactured at various settings of the 3D printing process such as the orientation of the specimen in print with respect to the printer building tray and the thickness of a single layer of the deposited material. Comparisons of the impact of these parameters on tribological performance of the sliding contact were analysed.

  • The impedance of hydrogen oxidation reaction in a proton exchange membrane fuel cell in the presence of carbon monoxide in hydrogen stream
    • Kazimierz Darowicki
    • Łukasz Gaweł
    • Michał Mielniczek
    • Artur Zieliński
    • Ewa Janicka
    • Jurgen Hunger
    • L. Jorissen
    2020 Pełny tekst APPLIED ENERGY

    Evaluation of performance of a proton exchange membrane fuel cell, which is affected by carbon monoxide that pollutes the hydrogen stream, was presented. This influence was studied for carbon monoxide concentration of 125–325 ppb, which are close to values specified in ISO 14687:2019 standard. Performed studies provided crucial information for further development of fuel cell as an energy source for automotive application. Impedance with the use of Dynamic Electrochemical Impedance Spectroscopy profile measurements were completed for chosen carbon monoxide concentration under a constant current load and anode impedance variations were determined as a function of the time exposed to carbon monoxide. A method to determine the impedance of hydrogen oxidation was proposed. It was determined how the carbon monoxide surface coverage of anodic catalyst varies as a function of time. The capacitance of the double electrical layer and the charge transfer resistance of anodic reaction are discussed to evaluate them with respect to exposure time and surface coverage. It has been shown that proposed methodology can be used as a universal tool for testing fuel cells for both research and industrial applications, with the overall aim of optimization, monitoring, and diagnostics of the fuel cell.

  • The In-Depth Studies of Pulsed UV Laser-Modified TiO2 Nanotubes: The Influence of Geometry, Crystallinity, and Processing Parameters
    • Łukasz Haryński
    • Katarzyna Grochowska
    • Piotr Kupracz
    • Jakub Karczewski
    • Emerson Coy
    • Katarzyna Siuzdak
    2020 Pełny tekst Nanomaterials

    The laser processing of the titania nanotubes has been investigated in terms of morphology, structure, and optical properties of the obtained material. The length of the nanotubes and crystallinity, as well as the atmosphere of the laser treatment, were taken into account. The degree of changes of the initial geometry of nanotubes were checked by means of scanning electron microscopy, which visualizes both the surface and the cross-section. The phase conversion from the amorphous to anatase has been achieved for laser-treated amorphous material, whereas modification of calcined one led to distortion within the crystal structure. This result is confirmed both by Raman and grazing incident XRD measurements. The latter studies provided an in-depth analysis of the crystalline arrangement and allowed also for determining the propagation of laser modification. The narrowing of the optical bandgap for laser-treated samples has been observed. Laser treatment of TiO2 nanotubes can lead to the preparation of the material of desired structural and optical parameters. The usage of the motorized table during processing enables induction of changes in the precisely selected area of the sample within a very short time.

  • The Indicators Assessment of Safety and Functionality of Tram Loops
    • Agnieszka Tubis
    • Mateusz Rydlewski
    • Marcin Budzyński
    2020 Pełny tekst Journal of KONBiN

    The new requirements set for tram loops mean that all stakeholders' expectations regarding their safety and functionality change. This creates a need for new tools for tram loop assessment, which are important interchanges, especially for people living outside the city limits or on their outskirts. The aim of the authors ’research is to create a indicators for assessing the safety and functionality of tram loops. Therefore, the article presents an overview of the research results in the area of tram transport and interchanges safety. Then the proposed indicator assessment for tram loops was described.

  • The Influence of Camera and Optical System Parameters on the Uncertainty of Object Location Measurement in Vision Systems
    • Jacek Skibicki
    • Anna Golijanek-Jędrzejczyk
    • Ariel Dzwonkowski
    2020 Pełny tekst SENSORS

    The article presents the influence of the camera and its optical system on the uncertainty of object position measurement in vision systems. The aim of the article is to present the methodology for estimating the combined standard uncertainty of measuring the object position with a vision camera treated as a measuring device. The identification of factors affecting the location measurement uncertainty and the determination of their share in the combined standard uncertainty will allow determining the parameters of the camera operation, so that the expanded uncertainty is as small as possible in the given measurement conditions. The analysis of the uncertainty estimation presented in the article was performed with the assumption that there is no influence of any external factors (e.g., temperature, humidity, or vibrations).

  • The Influence of COD Fraction Forms and Molecules Size on Hydrolysis Process Developed by Comparative OUR Studies in Activated Sludge Modelling
    • Jakub Drewnowski
    • Bartosz Szeląg
    • Li Xie
    • Xi Lu
    • Mahesh Ganesapillai
    • Chinmoy Kanti Deb
    • Joanna Szulżyk-Cieplak
    • Grzegorz Łagód
    2020 Pełny tekst MOLECULES

    The activated sludge models (ASMs) commonly used by the International Water Association (IWA) task group are based on chemical oxygen demand (COD) fractionations. However, the proper evaluation of COD fractions, which is crucial for modelling and especially oxygen uptake rate (OUR) predictions, is still under debate. The biodegradation of particulate COD is initiated by the hydrolysis process, which is an integral part of an ASM. This concept has remained in use for over 30 years. The aim of this study was to verify an alternative, more complex, modified (Activated Sludge Model No 2d) ASM2d for modelling the OUR variations and novel procedure for the estimation of a particulate COD fraction through the implementation of the GPS-X software (Hydromantis Environmental Software Solutions, Inc., Hamilton, ON, Canada) in advanced computer simulations. In comparison to the original ASM2d, the modified model more accurately predicted the OUR behavior of real settled wastewater (SWW) samples and SWW after coagulation–flocculation (C–F). The mean absolute relative deviations (MARDs) in OUR were 11.3– 29.5% and 18.9–45.8% (original ASM2d) vs. 9.7–15.8% and 11.8–30.3% (modified ASM2d) for the SWW and the C–F samples, respectively. Moreover, the impact of the COD fraction forms and molecules size on the hydrolysis process rate was developed by integrated OUR batch tests in activated sludge modelling.

  • The influence of combination of binding agents on fatigue properties of deep cold in-place recycled mixtures in Indirect Tensile Fatigue Test (ITFT)
    • Bohdan Dołżycki
    • Cezary Szydłowski
    • Mariusz Jaczewski
    2020 Pełny tekst CONSTRUCTION AND BUILDING MATERIALS

    The publication presents fatigue properties of cold recycled mixtures for eight combinations of binding agents (cement and bituminous emulsion). Cold recycled mixtures were evaluated in Indirect Tensile Fatigue Test (ITFT) at the temperature of 20 C in controlled stress mode. As a function of horizontal stress, fatigue life is strongly influenced by combination of the binding agents. When fatigue life is analyzed as a function of initial horizontal strain, the difference between different combinations decreases. In all cases, the influence of a specific binding agent is more visible for combinations with lower total amounts of the two agents.

  • The influence of polypropylene-block/graft-polycaprolactone copolymers on melt rheology, morphology, and dielectric properties of polypropylene/polycarbonate blends
    • Anton Ginzburg
    • Vaidyanath Ramakrishnan
    • Luca Rongo
    • Artur Rozanski
    • Miloud Bouyahyi
    • Lidia Jasinska-Walc
    • Rob Duchateau
    2020 RHEOLOGICA ACTA

    The paper discusses the relationship between rheology and morphology of immiscible polypropylene (matrix))/polycarbonate (dispersed phase) blends compatibilized with novel polypropylene-polycaprolactone block and graft copolymers. Transmission electron microscopy (TEM) experiments revealed uniform droplet morphologies and a reduction of the average size of the dispersed phase upon addition of the compatibilizer. The results suggested the influence of the molecular weight distribution (MWD)/chemical composition distribution (CCD) and topology of the compatibilizer on the compatibilizing performance. Graft copolymers were found to be most effective in reducing the size of the dispersed phase, whereas the performance of block copolymers appeared to be highly dependent on the block length of PP. Small-amplitude oscillatory rheological experiments revealed an increase in elasticity at low frequencies caused by the interfacial interactions induced by the compatibilizer. The effect was quantified using the relaxation time spectrums that displayed the additional peak at longer relaxation times via Gramespacher-Meissner method. Broadband dielectric spectroscopy (BDS) revealed the influence of the copolymer architecture and molecular weight of the polypropylene blocks on the properties of the interfacial polarization, which was in line with both rheology and morphology data.

  • The Influence of Sulfate on Anaerobic Ammonium Oxidation in a Sequencing Batch Reactor
    • Dominika Grubba
    • Joanna Majtacz
    2020 Pełny tekst Water

    Anaerobic ammonia-oxidizing bacteria have a more comprehensive metabolism than expected - there may be other electron acceptors that oxidize ammonium nitrogen under anaerobic conditions, in addition to the well-known nitrite nitrogen, one of which is sulfate in the sulfammox process. Sulfate-containing compounds are part of the medium for the anammox process, but their concentrations are not particularly high (0.2 g MgSO4 ∙ 7H2O/dm3 and 0.00625 g FeSO4/dm3). They can react to some extent with influent ammonium nitrogen. In this work, tests were carried out in two sequencing batch reactors with granular sludge. The first reactor (R1) operated in a 6 hour cycle, and the concentration of the inflowing sulfate was kept at 44 mg/dm3∙d. The second reactor (R2) was operated until the 36th day in a 6 hour cycle; the influencing concentration was 180 mg SO42−/dm3∙d from the 37th to 64th day in a 3 hour cycle, with an influencing concentration of 360 mg SO42−/dm3∙d; and from the 65th to 90th day, the reactor was operated again in a 6 hour cycle with an influencing concentration of 180 mg SO42−/dm3∙d. Along with the increased share of sulfate, both the ammonium utilization rate and specific anammox activity showed an increasing trend. As soon as the sulfate dosage was reduced, the ammonium utilization rate and specific anammox activity values dropped. Therefore, it can be concluded that sulfate-containing compounds contribute to the efficiency and rate of the anammox process.

  • The Influence of the Aircraft Operating Fluids on the Mechanical Parameters of the Airport Surface Concrete
    • Wojciech Żebrowski
    • Paweł Wolka
    • Marzena Kurpińska
    2020 Pełny tekst Materials

    The authors of the article assessed the impact of operating fluids used to service aircraft on changing mechanical parameters of cement concrete intended for airport pavement. The research concerned concrete designed with the use of CEM I 42.5N LH NA low-alkali cement, broken granite aggregate, fine washed aggregate, and admixtures. The analysis included the assessment of changes in dierences in endurance parameters over various research periods of up to 140 days. The obtained results allowed to carry out statistical analysis using the student’s T-test. Research has shown a significant impact of operational fluids used in aircraft on the surface concrete properties of the airport. A reduction in the compressive strength of concrete exposed to one of the tested operating liquid to a reduction of 7.2% was observed over a period of 140 days, while there was no significant impact of operating fluids on tensile strength at splitting.

  • The influence of the Cu2O deposition method on the structure, morphology and photoresponse of the ordered TiO2NTs/Cu2O heterojunction
    • Zuzanna Molenda
    • Katarzyna Grochowska
    • Jakub Karczewski
    • Jacek Ryl
    • Kazimierz Darowicki
    • Jakub Rysz
    • Adam Cenian
    • Katatrzyna SiuzdaK
    2020 Materials Research Express

    The increased interest in highly ordered titania structures exhibiting tubular shape that could be directly formed onto the stable substrate is related with the intensive research on their modification enabling absorption of light within the wide solar spectrum and its further conversion into electric or chemical energy. Among others, formation of uniform 3D heterojunctions based on the TiO2 nanotubes attracts attention since porous structure provides highly developed surface area whereas tubular shape ensures facilitated charge transport. Following that, we focus on the comparison of different electrochemical routes leading to the formation of Cu2O onto the titania nanotubes platform to improve energy harvesting. Proposed approach includes optimized potentiostatic and pulsed polarization of titania immersed in the basic electrolyte composed of Cu2+ ions stabilized by lactic acid. In this work, we demonstrate that at strictly selected deposition parameters, namely time, pulse width and cycle number, one can obtain titania nanotubes overgrown by Cu2O species uniformly distributed across the whole TiO2 layer as proved by secondary ion mass-spectrometry. X-ray photoelectron spectroscopy studies indicated purely Cu(I) oxide formation for pulsed deposition route. The photoactivity of obtained materials was verified both under vis and UV–vis irradiation. Depending on the incident light spectrum, variation in photoactivity was observed that is directly related with the charges generation and their transport within the junction. The transient photocurrent measurements show strong photocurrent enhancement for Cu2O modified titania comparing to pristine support and satisfactory photostability under visible light without any protective coating.

  • The Influence of the Cuboid Float’s Parameters on the Stability of a Floating Building
    • Artur Karczewski
    • Łukasz Piątek
    2020 Pełny tekst Polish Maritime Research

    Usually, the concept of sufficient stability of a floating structure is connected with the capacity to keep a small heel angle despite the moment of heeling. The variable responsible for these characteristics is the initial metacentric height, which is the relation between the hydrostatic features of the pontoon and the mass properties of the entire object. This article answers the questions of how heavy the floating system should be, what the minimum acceptable draft is, and whether it is beneficial to use internal fixed ballast. To cover various technologies, a theoretical model of a cuboid float with average density representing different construction materials was analysed. The results indicate that the common practice of using heavy and deep floating systems is not always reasonable. In the case of floating buildings, which, unlike ships, can be exploited only under small heel angles, the shape and width of the submerged part of the object may influence the stability more than the weight or draft.

  • The Influence of the Depth of Cut in Single-Pass Grinding on the Microstructure and Properties of the C45 Steel Surface Layer
    • Marek Szkodo
    • Karolina Chodnicka-Wszelak
    • Mariusz Deja
    • Alicja Stanisławska
    • Michał Bartmański
    2020 Pełny tekst Materials

    The paper contains the results of a metallographic examination and nanoindentation test conducted for the medium carbon structural steel with low content of Mn, Si, Cu, Cr, and Ni after its grinding to a depth ranging from 2 μm to 20 μm, at constant cutting speed (peripheral speed) of vs = 25 ms−1 and constant feed rate of vft = 1 m/min. Applied grinding parameters did not cause the surface layer hardening, which could generate an unfavorable stress distribution. The increase in the surface hardness was obtained due to the work hardening effect. Microstructure, phase composition, and chemical composition of the grinded surface layer were examined using an X‐ray diffractometer, light microscope, and scanning microscope equipped with X‐ray energy‐dispersive spectroscopy, respectively. Hardness on the grinded surface and on the cross‐section was also determined. It was shown that the grinding of C45 steel causes work hardening of its surface layer without phase transformation. What is more, only grinding to a depth of 20 μm caused the formation of an oxide scale on the work‐hardened surface layer. Nanoindentation test on the cross‐ section, at a short distance from the grinded surface, has shown that ferrite grains were more susceptible to work hardening than pearlite grains due to the creation of an equiaxed cellular microstructure, and that different dislocation substructure was created in the work‐hardened surface layer after grinding to different depths.

  • The Influence of the Electrodeposition Parameters on the Properties of Mn-Co-Based Nanofilms as Anode Materials for Alkaline Electrolysers
    • Karolina Cysewska
    • Maria Rybarczyk
    • Grzegorz Cempura
    • Jakub Karczewski
    • Marcin Łapiński
    • Piotr Jasiński
    • Sebastian Molin
    2020 Pełny tekst Materials

    In this work, the influence of the synthesis conditions on the structure, morphology, and electrocatalytic performance for the oxygen evolution reaction (OER) of Mn-Co-based films is studied. For this purpose, Mn-Co nanofilm is electrochemically synthesised in a one-step process on nickel foam in the presence of metal nitrates without any additives. The possible mechanism of the synthesis is proposed. The morphology and structure of the catalysts are studied by various techniques including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The analyses show that the as-deposited catalysts consist mainly of oxides/hydroxides and/or (oxy)hydroxides based on Mn2+, Co2+, and Co3+. The alkaline post-treatment of the film results in the formation of Mn-Co (oxy)hydroxides and crystalline Co(OH)2 with a β-phase hexagonal platelet-like shape structure, indicating a layered double hydroxide structure, desirable for the OER. Electrochemical studies show that the catalytic performance of Mn-Co was dependent on the concentration of Mn versus Co in the synthesis solution and on the deposition charge. The optimised Mn-Co/Ni foam is characterised by a specific surface area of 10.5 m2·g−1, a pore volume of 0.0042 cm3·g−1, and high electrochemical stability with an overpotential deviation around 330–340 mV at 10 mA·cm−2geo for 70 h.

  • The influence of thermal treatment on electrocatalytic properties of Mn-Co nanofilms on nickel foam toward oxygen evolution reaction activity
    • Karolina Cysewska
    • Grzegorz Cempura
    • Jakub Karczewski
    • Marcin Łapiński
    • Piotr Jasiński
    • Sebastian Molin
    2020 MATERIALS LETTERS

    This work evaluates electrodeposited and differently treated Mn-Co catalysts for their oxygen evolution reaction activity. Catalysts are evaluated in the as-deposited and heat treated state: after 350 C and 600 C. Results show that the highest electrochemical activity is obtained for the as-deposited Mn-Co oxyhydroxide, which possibly possess a layered double hydroxide structure. After the heat treatment process, especially after 600 C, the electrochemical performance decreases considerably.

  • The Influence of Water and Mineral Oil on Mechanical Losses in a Hydraulic Motor for Offshore and Marine Applications
    • Paweł Śliwiński
    2020 Pełny tekst Polish Maritime Research

    In this paper, mechanical losses in a hydraulic motor supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were onducted using a special design (prototype) of a hydraulic satellite motor. The design of the satellite motor is presented. This motor was developed to supply both with water and mineral oil and features a non-circular tooth working mechanism. The paper also characterizes sources of mechanical losses in this motor. On this basis, a mathematical model of these losses has been developed nd presented. The results of calculation of mechanical losses according to the model are compared with the experimental results. Experimental studies have shown that the mechanical losses in the motor supplied with water are 2.8 times greater than those in the motor supplied with oil. The work demonstrates that the mechanical losses in both the motor supplied with water and the one supplied with oil are described well by the mathematical model. It has been found that for the loaded motor working at high speed, the simulation results differ from experimental ones by no more than 3% for oil and 4% for water.

  • The influence of welding heat input on the quality and properties of high strength low-alloy dissimilar steel butt joints
    • Jacek Tomków
    • Jacek Haras
    2020 Pełny tekst Przegląd Spawalnictwa

    The paper presents the results of non-destructive and destructive tests of dissimilar highstrength low-alloy S460ML and S460N steel butt joints. These steels are characterized by similar mechanical properties, but their carbon equivalent CeIIW values are much different. The joints were made using different values of heat input for each welding bead. They were tested by non-destructive methods: visual, penetrant, radiographic and ultrasonic tests. Then, the destructive tests were made: static tensile test, bending test, impact test and Vickers HV10 hardness measurements. The results of prepared examinations showed, that welding with higher heat input has significant impact on the mechanical properties of the dissimilar steel joints the joint welded with bigger heat input was characterized by better mechanical properties.

  • The Influent Effects of Flow Rate Profile on thePerformance of Microbial Fuel Cells Model
    • Szymon Potrykus
    • Sara Mateo
    • Janusz Nieznański
    • Francesco Jesus Fernández-Morales
    2020 Pełny tekst ENERGIES

    The energy contained in wastewaters has been identified as a promising sustainableenergy resource that could be harvested by using microbial fuel cells (MFC). When dealing with realwastewaters, the MFCs should be able to manage high flow rates and flow rates fluctuations. In thiswork, the short-term effects of the influent flow rate variations on the performance of a microbialfuel cell has been studied. With this aim, the influent flow rate was stepwise increased from 0.72 to7.2 L/d and then stepwise decreased. The obtained results indicate that, on the one hand, an increasein the influent flow rate leads to higher chemical oxygen demand removal rates up to 396 g/(L/d) andhigher electric power generation almost 18 mW/m2, but to lower coulombic efficiencies. On the otherhand, the reduction of the flow rate increases the coulombic efficiencies, as well as the percentageof chemical oxygen demand removed, but decreases electric power generation. In the short-term,the exposition to higher influent flow rates causes the growth of the microbial population of the MFC,the growth of the non-electrogenic microorganisms being higher than that of the electrogenic ones.The higher growth of non-electrogenic microorganisms may lead to lower coulombic efficiencies.

  • The interaction parameters for solutions of n-butylurea in aqueous solutions of N-methylacetamide – The volumetric and compressibility studies between 288.15 K and 308.15 K
    • Emilia Kaczkowska
    • Jarosław Wawer
    • Magdalena Tyczyńska
    • Małgorzata Jóźwiak
    • Joanna Krakowiak
    2020 JOURNAL OF CHEMICAL THERMODYNAMICS

    Densities and speed of sound were measured for solutions of n-butylurea in aqueous solution of Nmethylacetamide 2, 4, 6 and 8 (mol/kg) at T = (288.15, 298.15 and 308.15) K. From these data the apparent molar volumes, Vf, the apparent molar isentropic compressions, KSf, of the solute were determined. The concentration dependencies of the calculated quantities have been used to obtain the standard partial molar parameters. The latter values were combined with the previously published volumetric and compressibility data for n-butylurea in pure water to obtain the partial molar properties of transfer from water to aqueous N-methylacetamide solutions. These parameters were used to determine the interaction parameters according to the McMillan-Mayer theory. The calculated parameters and their temperature characteristics are discussed in terms of solute–solvent, solute–solute and solute–cosolute interactions.

  • The managerial role in organizational culture as perceived by management students
    • Marta Szeluga-Romańska
    • Anna Modzelewska
    2020 Pełny tekst Journal of Entrepreneurship, Management and Innovation

    This paper aims at illustrating the multidimensional role of the manager and its mutual influence on organizational culture from amanagement students’ perspective. The main part of the text was based on own qualitative research – interviews, a questionnaire, and a narrative collage – which was conducted over a 10 year period among management students. Ninety-seven students from the Jagiellonian University and the Gdańsk University of Technology took part in the research. In order to gather, analyze and interpret the data, and to achieve reliable results, we followed the thematic analysis rules. We investigated the empirical material, provided by the management students responses to the research questions posed in the questionnaire, in the search for interesting threads, seeking a definition and an understanding of the term “manager” and the specifics of a manager’s work. We also presented several quotes from the data in accordance with the principles of data analysis in qualitative research methodology. Four different prisms were identified: gender, relational, constant learning and professional, described as the areas of managerial duties, features, and expectations. The article’s key value is the focus on students’ perception – an idealized construct of the managerial role, which states a benchmark for their own actual and prospect managerial performance. Such a perspective is very important for practice as well as for education. From a practical point of view, some management students will manage teams or organizations in the future. They should be aware of managerial duties’ elaborate character and the multiple demands on the role’s performance. They will shape the role by themselves. On the other hand, from an educational point of view, it is essential to give students some insight into their prospective role, understand the elaborate organizational relations, and the activities that appear in organizational culture that always influence management.

  • The mechanical properties and bactericidal degradation effectiveness of tannic acid-based thin films for wound care
    • B. Kaczmarek
    • Marcin Wekwejt
    • K. Nadolna
    • A. Owczarek
    • O. Mazur
    • Anna Pałubicka
    2020 Pełny tekst Journal of the Mechanical Behavior of Biomedical Materials

    The surface area is the most important aspect when considering the interactions between a material and the surrounding environment. Chitosan (CTS) and tannic acid (TA) were previously successfully tested by us to obtain thin films to serve as wound dressings or food packaging materials. However, surface properties as well as the antimicrobial activity of the material were not considered. They are important if the material is likely to find application in biomedical or food packaging application. Thereby, this study is a further investigation of chitosan/tannic acid films surface properties. The results showed that higher content of tannic acid increases the surface free energy and roughness, which is beneficial when considering the application of the materials as wound dressings. However, higher content of chitosan provides better antibacterial properties. Hence, the most optimal complex of chitosan and tannic acid for proposed application is the ratio 80/20.

  • The mechanisms of degradation of titanium dental implants
    • Agnieszka Ossowska
    • Andrzej Zieliński
    2020 Pełny tekst Coatings

    Titanium dental implants show very good properties, unfortunately there are still issues regarding material wear due to corrosion, implant loosening, as well as biological factors—allergic reactions and inflammation leading to rejection of the implanted material. In order to avoid performing reimplantation operations, changes in the chemical composition and/or modifications of the surface layer of the materials are used. This research is aimed at explaining the possible mechanisms of titanium dissolution and the role of oxide coating, and its damage, in the enhancement of the corrosion process. The studies of new and used implants were made by scanning electron microscopy and computer tomography. The long-term chemical dissolution of rutile was studied in Ringer’s solution and artificial saliva at various pH levels and room temperature. Inductively coupled plasma mass spectrometry (ICP-MS) conjugated plasma ion spectrometry was used to determine the number of dissolved titanium ions in the solutions. The obtained results demonstrated the extremely low dissolution rate of rutile, slightly increasing along with pH. The diffusion calculations showed that the diffusion of titanium through the oxide layer at human body temperature is negligible. The obtained results indicate that the surface damage followed by titanium dissolution is initiated at the defects caused by either the manufacturing process or implantation surgery. At a low thickness of titanium oxide coating, there is a stepwise appearance and development of cracks that forms corrosion tunnels within the oxide coating.

  • THE MELT FLOWABILITY AND TENSILE PERFORMANCE OF POLY (-CAPROLACTONE)/BREWERS’ SPENT GRAIN COMPOSITES AS A FUNCTION OF FILLER MODIFICATION
    • Aleksander Hejna
    2020 Pełny tekst

    Nowadays, it is essential to reduce the environmental impact of products and technologies. Such an approach should be highlighted in all research activities. In the case of polymer composites, it can be realized by introducing by-products or waste materials as fillers. An auspicious example of such material is the brewers’ spent grain, the major byproduct of the beer production. Its chemical composition, relatively similar to conventional lignocellulose fillers, enables its application to manufacturing wood-polymer composites. However, to enhance its compatibility with polymer matrices, it could be modified. Therefore, in the presented paper, the impact of the extrusion grinding of brewers’ spent grain on the processing and mechanical performance of polymer composites was evaluated.

  • The Method of Selecting the Interval of Functional Tests Taking into Account Economic Aspects and Legal Requirements
    • Jan Piesik
    • Emilian Piesik
    • Marcin Śliwiński
    2020 Pełny tekst Journal of Automation, Mobile Robotics and Intelligent Systems - JAMRIS

    The article discusses the problem of choosing the optimal frequency of functional tests, taking into account the reliability and law requirements, but also the impact of business aspects in the company. The subject of functional test interval is well described for purposes of the process industry. Unfortunately, this is not the case for the machinery safety functions with low demand mode. This is followed by a presentation of the current business approach, which, in order to achieve industrial excellence, monitor their performance through the appropriate selection of key performance indicators. In addition, companies are increasingly exploring potential risks in the following areas: new challenges in advanced risk management, including the perception of the company’s facilities as a safe workplace insight of customers and business partners. Eliminating potential hazards is increasingly taking into account, especially the impact of human activity and its interaction with machines. The case study has been presented based on the machines used for the production of tire semi-finished products. In this article, the authors propose a solution for selecting the interval of functional tests of safety functions and additional machine protection measures as a compromise to achieve satisfactory results in terms of safety requirements, performance and legal requirements.

  • The Neural Knowledge DNA Based Smart Internet of Things
    • Haoxi Zhang
    • Fei Li
    • Juan Wang
    • Zuli Wang
    • Lei Shi
    • Cesar Sanin
    • Edward Szczerbicki
    2020 Pełny tekst CYBERNETICS AND SYSTEMS

    ABSTRACT The Internet of Things (IoT) has gained significant attention from industry as well as academia during the past decade. Smartness, however, remains a substantial challenge for IoT applications. Recent advances in networked sensor technologies, computing, and machine learning have made it possible for building new smart IoT applications. In this paper, we propose a novel approach: the Neural Knowledge DNA based Smart Internet of Things that enables IoT to extract knowledge from past experiences, as well as to store, evolve, share, and reuse such knowledge aiming for smart functions. By catching decision events, this approach helps IoT gather its own daily operation experiences, and it uses such experiences for knowledge discovery with the support of machine learning technologies. An initial case study is presented at the end of this paper to demonstrate how this approach can help IoT applications become smart: the proposed approach is applied to fitness wristbands to enable human action recognition.

  • The New Klebsiella pneumoniae ST152 Variants with Hypermucoviscous Phenotype Isolated from Renal Transplant Recipients with Asymptomatic Bacteriuria-Genetic Characteristics by WGS.
    • Magdalena Wysocka
    • Roxana Zamudio
    • Marco R Oggioni
    • Justyna Gołębiewska
    • Aleksandra Dudziak
    • Beata Krawczyk
    2020 Pełny tekst Genes

    Klebsiella pneumoniae (Kp) is one of the most important etiological factors of urinary tract infections in renal transplant (RTx) recipients. We described the antimicrobial susceptibility phenotypes and genomic features of two hypermucoviscous (HM) Kp isolates recovered from RTx recipients with asymptomatic bacteriuria (ABU). Using whole genome sequencing (WGS) data, we showed that the strains belong to the ST152 lineage with the KL149 capsular serotype, but without rmpA/magA genes, which is typical for HM+ hypervirulent Kp. These new strains carried virulence-associated genes that predispose for urinary tract infections (UTIs). Likewise, both strains carried the ecp gene encoding pilus common for extended-spectrum β-lactamase (ESBL) Escherichia coli. Although the two ST152 isolates were closely related and differed by only nine single nucleotide polymorphisms (SNPs) in their chromosomes, they had different plasmid compositions and chromosomal elements, with isolate KP28872 carrying an ESBL plasmid and an integrative conjugative element. These two isolates are an example of the high plasticity of the K. pneumoniae accessory genome. The identification of patients with ABU matched with the correct epidemiological profiling of isolates could facilitate interventions to prevent or rapidly treat K. pneumoniae infections.

  • The new silica-based coated SPME fiber as universal support for the confinement of ionic liquid as an extraction medium
    • Karolina Konieczna
    • Kateryna Yavir
    • Mansoureh Kermani
    • Aleksandra Mielewczyk-Gryń
    • Adam Kloskowski
    2020 SEPARATION AND PURIFICATION TECHNOLOGY

    The new silica-based SPME fiber coating is reported for the first time as universal support purposed to confinement of ionic liquid as an extraction medium. Fiber coating was prepared by the sol-gel process, using potassium silicate (K2SiO3) as a precursor and dimethylformamide (DMF) as a pore-forming medium. The concept of synthesis assumes obtaining a solid porous material on the surface of the glass rod and, being characterized by high porosity, mechanical strength, and uniformity of shape. In the course of the research, several parameters were optimized, like the type of silica precursor, drying steps, time and temperature of aging. Properties of obtained coatings were evaluated using optical and scanning electron microscopies and thermal adsorption/desorption measurements. Finally, the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate [C2C1IM][BF4] was immobilized in silica pores of the prepared fiber. The usefulness of the obtained SPME silica-IL fibers was investigated by its utilization in model analytical procedures. Robustness of produced fibers is supported by high fiber-to-fiber reproducibility (%) as well as by a long lifetime reaching over 50 extraction/desorption cycles.

  • The New Test Procedure for Group-Type Composition of Base Oils of Lubricating Oils, Especially Emitted into the Environment
    • Paulina Nowak
    • Karolina Kucharska
    • Marian Kamiński
    2020 Pełny tekst ENERGIES

    Mineral base oil, a product of multistep fine refining of the relevant fractions from vacuum distillation of crude oil, is a main component of so-called mineral lubricating oils containing aliphatic and alicyclic substituted aromatic hydrocarbons, i.e., derivatives of benzene and biphenyl. Mineral lubricating oil is composed mostly of mineral base oil and a low amount of enriching additives, most often products of advanced organic chemical technology. The application of mineral lubricating oils in open cutting systems has a very negative impact on environment and on the operator’s health. This work presents a simple, cheap and fast methodology allows identification of the group-type composition of base oil in lubricating oil and to estimate the content or total absence of base oil of mineral and vegetable origin in lubricating oil. The first step of the test is an in-situ screening for fluorescence of petroleum fraction under the 365 nm light. The next is the performance of infrared spectra with Fourier transformation (FT-MIR) to identify and estimate the content of vegetable oil and its derivatives and the performance of UV-Vis spectra to identify and determine the content of aromatic hydrocarbons, as well as dyes present in the lubricating oil. The last stage is normal phase thin layer chromatography (NP-TLC) using different visualization methods to evaluate the group-type composition of lubricating oil. Effectivity of the developed procedure has been confirmed during control of group-type composition evaluation of lubricating oils in cutting systems. The procedure can be also applied with respect to different oil matrices.

  • The occurrence and role of Nitrospira in nitrogen removal systems
    • Mohamad-Javad Mehrani
    • Dominika Sobotka
    • Przemysław Kowal
    • Sławomir Ciesielski
    • Jacek Mąkinia
    2020 Pełny tekst BIORESOURCE TECHNOLOGY

    Application of the modern microbial techniques changed the paradigm about the microorganisms performing nitrification. Numerous investigations recognized representatives of the genus Nitrospira as a key and predominant nitrite-oxidizing bacteria in biological nutrient removal systems, especially under low dissolved oxygen and substrate conditions. The recent discovery of Nitrospira capable of performing complete ammonia oxidation (comammox) raised a fundamental question about the actual role of Nitrospira in both nitrification steps. This review summarizes the current knowledge about morphological, physiological and genetic characteristics of the canonical and comammox Nitrospira. Potential implications of comammox for the functional aspects of nitrogen removal have been highlighted. The complex meta-analysis of literature data was applied to identify specific individual variables and their combined interactions on the Nitrospira abundance. In addition to dissolved oxygen and influent nitrogen concentrations, temperature and pH may play an important role in enhancing or suppressing the Nitrospira activity.

  • The ONETEP linear-scaling density functional theory program
    • Joseph C. A. Prentice
    • Jolyon Aarons
    • James C. Womack
    • Alice E. A. Allen
    • Lampros Andrinopoulos
    • Lucian Anton
    • Robert A. Bell
    • Arihant Bhandari
    • Gabriel A. Bramley
    • Robert J. Charlton
    • Rebecca J. Clements
    • Daniel J. Cole
    • Gabriel Constantinescu
    • Fabiano Corsetti
    • Simon Dubois
    • Kevin K. B. Duff
    • José María Escartín
    • Andrea Greco
    • Quintin Hill
    • Louis P. Lee
    • Edward Linscott
    • David D. O’Regan
    • Maximillian J. S. Phipps
    • Laura Ratcliff
    • Álvaro Ruiz Serrano
    • Edward W. Tait
    • Gilberto Teobaldi
    • Valerio Vitale
    • Nelson Yeung
    • Tim J. Zuehlsdorff
    • Jacek Dziedzic
    • Peter Haynes
    • Nicholas Hine
    • Arash Mostofi
    • Mike Payne
    • Chris-Kriton Skylaris
    2020 Pełny tekst JOURNAL OF CHEMICAL PHYSICS

    We present an overview of the ONETEP program for linear-scaling density functional theory (DFT) calculations with large basis set (planewave) accuracy on parallel computers. The DFT energy is computed from the density matrix, which is constructed from spatially localized orbitals we call Non-orthogonal Generalized Wannier Functions (NGWFs), expressed in terms of periodic sinc (psinc) functions. During the calculation, both the density matrix and the NGWFs are optimized with localization constraints. By taking advantage of localization, ONETEP is able to perform calculations including thousands of atoms with computational effort, which scales linearly with the number or atoms. The code has a large and diverse range of capabilities, explored in this paper, including different boundary conditions, various exchange– correlation functionals (with and without exact exchange), finite electronic temperature methods for metallic systems, methods for strongly correlated systems, molecular dynamics, vibrational calculations, time-dependent DFT, electronic transport, core loss spectroscopy, implicit solvation, quantum mechanical (QM)/molecular mechanical and QM-in-QM embedding, density of states calculations, distributed multipole analysis, and methods for partitioning charges and interactions between fragments. Calculations with ONETEP provide unique insights into large and complex systems that require an accurate atomic-level description, ranging from biomolecular to chemical, to materials, and to physical problems, as we show with a small selection of illustrative examples. ONETEP has always aimed to be at the cutting edge of method and software developments, and it serves as a platform for developing new methods of electronic structure simulation. We therefore conclude by describing some of the challenges and directions for its future developments and applications.

  • The Palais–Smale condition for the Hamiltonian action on a mixed regularity space of loops in cotangent bundles and applications
    • Luca Asselle
    • Maciej Starostka
    2020 Pełny tekst CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS

    We show that the Hamiltonian action satisfies the Palais-Smale condition over a “mixed regular- ity” space of loops in cotangent bundles, namely the space of loops with regularity H^s, s ∈ (1/2, 1), in the baseand H^{1−s} in the fiber direction. As an application, we give a simplified proof of a theorem of Hofer-Viterbo on the existence of closed characteristic leaves for certain contact type hypersufaces in cotangent bundles.

  • The performance of ETFs on developed and emerging markets with consideration of regional diversity
    • Krystian Zawadzki
    2020 Pełny tekst Quantitative Finance and Economics

    This study evaluates the performance of Exchange-Traded Funds (ETFs) by using various tracking error calculation approaches. The aim of the paper is, on the one hand, an evaluation of the performance of ETFs relative to their benchmarking indexes and, on the other, an endeavour to specify any relationship between this performance and both geographical location and the degree of market development. The research was conducted on the basis of 18 different ETFs issued by iShares, six for each of three regions: both Americas, Asia and Europe. The sole criterion for ETF’s selection was the benchmark. All data were collected with daily frequency. They range from January 2013 to December 2019. The results indicate that ETFs do not mimic their corresponding indexes well. Calculated tracking errors do not equal zero and are often significantly negative. Furthermore, the value of tracking errors depends on the region and the degree of market development.

  • The Possibilities of Improving the Fatigue Durabilityof the Ship Propeller Shaft by Burnishing Process
    • Stefan Dzionk
    • Włodzimierz Przybylski
    • Bogdan Ścibiorski
    2020 Pełny tekst Machines

    Heavily loaded structural elements operating in a corrosive environment are usuallyquickly destroyed. An example of such an element is a ship propeller operating in a seawaterenvironment. This research presents a fatigue resistance test performed on elements operating inseawater. Different processing parameters applied on the samples in particular were compared withthe specimens whose surface had been burnished differently and they were compared to specimenswith a grinded surface. The research shows that the structural elements whose surface has beenburnished can have up to 30% higher fatigue strength in a seawater environment than the elementswhose surface has been grinded. During burnishing, an important feature of the process is the degreeof cold rolling of the material. The resistance of the component to fatigue loads increases only to acertain level with increasing the degree of the cold rolling. Further increasing the degree of coldrolling reduces the fatigue strength. Introducing additional stresses in the components (e.g., assemblystresses) reduces the fatigue strength of this component in operation and these additional stressesshould be accounted for while planning the degree of the cold rolling value. A device that allowsfor simultaneous turning and shaft burnishing with high slenderness is presented in the appendixof this article. This device can be connected to the computerized numerical control system andexecuted automatic process according to the machining program; this solution reduces the number ofoperations and cost in the process

  • The Potential of Improving Air Quality by Urban Mobility Management: Policy Guidelines and a Case Study
    • Joanna Badach
    2020 Pełny tekst IOP Conference Series: Earth and Environmental Science

    There is a growing recognition among planners and policy makers that proper transformation of urban mobility systems is crucial to the reduction of air pollution emission. The main objective of the work was to review the current urban mobility strategies in the city of Gdańsk, Poland in terms of their potential for the improvement of urban air quality. Firstly, general policy guidelines for mobility systems were formulated based on a review of recent relevant studies and existing solutions from various European and Asian cities. Then the main spatial characteristics of the transport system and mobility patterns in Gdańsk were determined and visualised by means of GIS-based tools, supported by the analysis of local urban and environmental planning documents. The current air quality status in Gdańsk was also described. Subsequently, the policies proposed in two documents for the urban mobility management in Gdańsk were identified and cross-compared with the previously reviewed solutions from other cities in terms of air quality improvement. The results showed that the strategies for air pollution mitigation are not integrated with the process of urban planning in Gdańsk to a sufficient degree. Finally, some recommendations were also suggested to improve the current strategies.

  • The power of personal brand authenticity and identification: top celebrity players’ contribution to loyalty toward football
    • Wioleta Kucharska
    • Ilenia Confente
    • Federico Brunetti
    2020 Pełny tekst Journal of Product & Brand Management

    Purpose: In the current era of fake news, illusions, manipulations, and other artificial attributes of virtuality and reality, authenticity is a virtue that people highly appreciate. This study examines the influence of the personal brand authenticity of top football players on loyalty to the football discipline in general, via the mediation of personal brand identification. Design: Based on data collected from a convenience sample of 562 respondents from Poland via an electronic survey and analyzed using the structural equation modeling method this study explored, first, the influence of top football players’ personal brand authenticity on consumers’ identification with these football players, and second, how this identification may lead to enhancing loyalty to the football discipline. Finally, it verified how the loyalty effect (attitudinal and behavioral) varies across different categories of spectators. Originality: This study presents evidence that the personal authenticity of football celebrities to measure loyalty to the football discipline in general, as mediated by personal brand identification. Moreover, this study proves that the loyalty to football driven by the personal brand authenticity of football stars differs between spectators’ categories, and it differs from the loyalty driven by clubs. Findings: Personal brand identification with authentic football stars is a focal factor enabling the creation of loyalty (attitudinal and behavioral) to the whole discipline. Consumers’ perceptions of the authenticity of the personal brands of football players play a role in increasing identification with these personal brands. This identification is essential in achieving loyalty to football as a sports discipline via football celebrities. Implications: Football players perceived as authentic are evaluated more positively, leading to consumer identification with these players, which, in turn, increases consumers’ loyalty to football. Thus, the presence of authentic, skilled players is important for football, but the actual loyalty effect from authenticity can be achieved only by identification. Therefore, football 3 requires exceptional, strong stars who reflect a set of desired personal values. Further research is needed to identify the desired set of values that leads to identification with football stars.

  • The preparation and evaluation of core-shell magnetic dummy-template molecularly imprinted polymers for preliminary recognition of the low-mass polybrominated diphenyl ethers from aqueous solutions
    • Mariusz Marć
    • Piotr Paweł Wieczorek
    2020 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    The design, preparation process, binding abilities, morphological characteristic and prospective field of application of dummy-template magnetic molecularly imprinted polymer (DMMIP) for preliminary recognition of the selected low-mass polybrominated diphenyl ethers (PBDE-47 and PBDE-99) from aquatic environment were investigated. The surface of iron oxide (Fe3O4) nanopowder (50-100 nm particles size) was modified with tetraethoxysilane and next prepared Fe3O4@SiO2 particles were dispersed in anhydrous toluene functionalized by (3-aminopropyl)triethoxysilane. Finally, MIPs' thin film layer on the surface of Fe3O4@SiO2@NH2 was formed in acetonitrile as a solvent solution, using ethylene glycol dimethacrylate as the cross-linker, building monomer, 1,1′-Azobis(cyclohexanecarbonitrile) as the radical initiator, methacrylic acid as a functional monomer and 4,4'- Dihydroxydiphenyl ether as the dummy template molecule as a structural analogue of low-mass PBDEs. To characterize the chemical structure of prepared DMMIPs, the Fourier transform infrared spectroscopy analysis was performed. The specific surface area of the developed sorbent was estimated using Brauner-Emmet-Teller nitrogen adsorption/desorption analysis. To assess the average pore sizes, pore diameters and pore volumes of the prepared sorbent, the Barret-Joyner-Halenda technique was applied. The average values of imprinting factor for PBDE-47 and PBDE-99 were 11.3 ± 1.6 and 13.7 ± 1.2, respectively. The average value of recovery of PBDE-47 and PBDE-99 for developed DMMIPs from modelling water : methanol solution were 85.4 ± 6.7% and 86.4 ± 9.4%, respectively. In a case of spiked distilled water, tap water as well as local river water the calculated recovery values ranged from 65%% up to 82% and from 33% up to 76% for PBDE-47 and PBDE-99, respectively. Following the preliminary research on selected water samples, the proposed combination of imprinting technology and core–shell materials with magnetic properties might be considered as a promising sorption tool used for targeted recognition of low-mass PBDEs in aquatic solutions.

  • The Product of Matrix Metalloproteinase Cleavage of Doxorubicin Conjugate for Anticancer Drug Delivery: Calorimetric, Spectroscopic, and Molecular Dynamics Studies on Peptide–Doxorubicin Binding to DNA
    • Kamila Butowska
    • Krzysztof Żamojć
    • Mateusz Kogut
    • Witold Kozak
    • Dariusz Wyrzykowski
    • Wiesław Wiczk
    • Jacek Czub
    • Jacek Piosik
    • Janusz Rak
    2020 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Matrix metalloproteinases (MMPs) are extracellular matrix degradation factors, promoting cancer progression. Hence, they could provide an enzyme-assisted delivery of doxorubicin (DOX) in cancer treatment. In the current study, the intercalation process of DOX and tetrapeptide-DOX, the product of the MMPs' cleavage of carrier-linked DOX, into dsDNA was investigated using stationary and time-resolved fluorescence spectroscopy, UV-Vis spectrophotometry and isothermal titration calorimetry (ITC). The molecular dynamics (MD) simulations on the same tetrapeptide-DOX…DNA and DOX…DNA systems were also performed. The undertaken studies indicate that DOX and tetrapeptide-DOX can effectively bond with dsDNA through the intercalation mode; however, tetrapeptide-DOX forms less stable complexes than free DOX. Moreover, the obtained results demonstrate that the differences in DNA affinity of both forms of DOX can be attributed to different intercalation modes. Tetrapeptide-DOX shows a preference to intercalate into DNA through the major groove, whereas DOX does it through the minor one. In summary, we can conclude that the tetrapeptide-DOX intercalation to DNA is significant and that even the lack of non-specific proteases releasing DOX from the tetrapeptide conjugate, the presence of which is suggested by the literature for the efficient release of DOX, should not prevent the cytostatic action of the anthracycline.

  • The Proposition of an Automated Honing Cell with Advanced Monitoring
    • Adam Barylski
    • Piotr Sender
    2020 Pełny tekst Machines

    Honing of holes allows for small shape deviation and a low value of a roughness profile parameter, e.g., Ra parameter. The honing process heats the workpiece and raises its temperature. The increase in temperature causes thermal deformations of the honed holes. The article proposes the construction of a honing cell, containing in addition to CNC honing machine: thermographic camera, sound intensity meter, and software for collecting and analyzing data received during machining. It was proposed that the level of sound intensity obtained during honing could be monitored continuously and that the images from a thermographic camera could be analyzed on-line. These analyses would be aimed at supervising honing along with the on-line correction of machining parameters. In addition to the oil cooler, the machining cell may have an automatic selection of the grain trajectory shape, with specified value of the radii of curvature of the abrasive grain trajectories, according to the wall thickness of the honed workpiece, which will result in reducing the temperature generated during honing. Automated honing cell can mostly increase honing process efficiency. Simulations in FlexSim showed the possibility of increasing the efficiency of the honing process more than 20 times.

  • The pulsed laser ablation synthesis of colloidal iron oxide nanoparticles for the enhancement of TiO2 nanotubes photo-activity
    • Piotr Kupracz
    • Emerson Coy
    • Katarzyna Grochowska
    • Jakub Karczewski
    • Jakub Rysz
    • Katarzyna Siuzdak
    2020 APPLIED SURFACE SCIENCE

    The rapid, only a few minutes long synthesis of FeO, Fe3O4, and Fe2O3nanoparticles mixture utilizing the pulsedlaser ablation using simply pure iron target and water was demonstrated. The size and crystal phase of Fe-basedNPs were characterized using DLS and HR-TEM techniques, respectively. The metastable suspension of FeO,Fe3O4, and Fe2O3nanoparticles was used to the decoration of anodized TiO2nanotubes (TiO2-NTs) by means ofthe ultrasonic bath. SEM inspection confirms preservation of the ordered morphology even upon 60 min longexposition to the ultrasounds whereas TOF SIMS indicated penetration of iron species down to the TiO2-NTsbase. Finally, the electrochemical investigation of decorated and bare TiO2-NTs has shown a response typical forFe2+/Fe3+iron species and the boosted activity towards oxygen evolution reaction in the anodic regime. As ofhigh importance, for the 30 min long ultrasound-assisted modification, the photocurrent was enhanced almost2.5 times comparing to the pristine material exposed to the solar light, although differences in optical propertieswere negligible. Taking into account outstanding activity namely response upon irradiation and effectiveness ofwater splitting, the proposed approach can be regarded as a facile one generating much less waste in comparisonto typical wet-chemistry methods.

  • The Quantum Efficiency Roll-Off Effect in Near-Infrared Organic Electroluminescent Devices with Iridium Complexes Emitters
    • Wojciech Mróz
    • Sagar Kesarkar
    • Alberto Bossi
    • Daniel Pelczarski
    • Piotr Grygiel
    • Waldemar Stampor
    2020 Pełny tekst Materials

    The electroluminescence quantum efficiency roll-off in iridium(III)-based complexes, namely Ir(iqbt)2(dpm) and Ir(iqbt)3(iqbt=1 (benzo[b]thiophen-2-yl)-isoquinolinate, dpm=2,2,6,6-tetramethyl-3,5-heptanedionate) utilized as near-infrared emitters in organic light emitting diodes with remarkable external quantum efficiencies, up to circa 3%, 1.5% and 1%, are measured and analyzed. With a 5–6 weight % of emitters embedded in a host matrix, the double-layer solution-processed structure as well as analogous three-layer one extended by a hole-conducting film are investigated. The triplet-polaron, the Onsager electron-hole pair dissociation and the triplet-triplet annihilation approaches were used to reproduce the experimental data. The mutual annihilation of triplets in iridium emitters was identified as prevailingly controlling the moderate roll-off,with the interaction between those of iridium emitters and host matrixes found as being less probable. Following the fitting procedure, the relevant rate constant was estimated to be(0.5−12)×10−12cm3/s,values considered to be rather too high for disordered organic systems, which was assigned to the simplicity of the applied model. A coexistence of some other mechanisms is therefore inferred, ones, however, with a less significant contribution to the overall emission quenching.

  • The Quaternization Reaction of 5-O-Sulfonates of Methyl 2,3-o-Isopropylidene-β-D-Ribofuranoside with Selected Heterocyclic and Aliphatic Amines
    • Barbara Dmochowska
    • Rafał Ślusarz
    • Jarosław Chojnacki
    • Justyna Samaszko-Fiertek
    • Janusz Madaj
    2020 Pełny tekst MOLECULES

    The synthesis of N-((methyl 5-deoxy-2,3-O-isopropylidene-β-D-ribofuranoside)-5-yl) ammonium salts are presented. To determine the effect of the nucleophile type and outgoing group on the quaternization reaction, selected aliphatic and heterocyclic aromatic amines reacted with: methyl 2,3-O-isopropylidene-5-O-tosyl-β-D-ribofuranoside or methyl 2,3-O-isopropylidene-5-O-mesyl-β-D -ribofuranoside or methyl 2,3-O-isopropylidene-5-O-triflyl-β-D-ribofuranoside were performed on a microscale. High-resolution 1H- and13C-NMR spectral data for all new compounds were recorded. Additionally, the single-crystal X-ray diffraction analysis for methyl 2,3-O-isopropylidene-5-O-mesyl-β-D-ribofuranoside and selected in silico interaction models are reported

  • The Reactivity of Phosphanylphosphinidene Complexes of Transition Metals Toward Terminal Dihaloalkanes
    • Anna Ordyszewska
    • Natalia Szynkiewicz
    • Jarosław Chojnacki
    • Jerzy Pikies
    • Rafał Grubba
    2020 Pełny tekst INORGANIC CHEMISTRY

    The reactivities of phosphanylphosphinidene complexes [(DippN)2W(Cl)(η2-P−PtBu2)]− (1), [(pTol3P)2Pt(η2- P=PtBu2)] (2), and [(dppe)Pt(η2-P=PtBu2)] (3) toward dihaloalkanes and methyl iodide were investigated. The reactions of the anionic tungsten complex (1) with stochiometric Br(CH2)nBr (n = 3, 4, 6) led to the formation of neutral complexes with a tBu2PP(CH2)3Br ligand or neutral dinuclear complexes with unusual tetradentate tBu2PP(CH2)nPPtBu2 ligands (n = 4, 6). The methylation of platinum complexes 2 and 3 with MeI yielded neutral or cationic complexes bearing side-on coordinated tBu2P−P-Me moieties. The reaction of 2 with I(CH2)2I gave a platinum complex with a tBu2P-P-I ligand. When the same dihaloalkane was reacted with 3, the P-P bond in the phosphanylphosphinidene ligand was cleaved to yield tBu2PI, phosphorus polymers, [(dppe)PtI2] and C2H4. Furthermore, the reaction of 3 with Br(CH2)2Br yielded dinuclear complex bearing a tetraphosphorus tBu2PPPPtBu2 ligand in the coordination sphere of the platinum. The molecular structures of the isolated products were established in the solid state and in solution by single-crystal X-ray diffraction and NMR spectroscopy. DFT studies indicated that the polyphosphorus ligands in the obtained complexes possess structures similar to free phosphenium cations tBu2P+=P−R (R = Me, I) or (tBu2P+=P)2.

  • The reduction of auxiliaries power demand: The challenge for electromobility in public transportation
    • Mikołaj Bartłomiejczyk
    • Robert Kołacz
    2020 Pełny tekst JOURNAL OF CLEANER PRODUCTION

    An important role in the consumption of electric energy in urban transport are non-traction needs (auxiliaries), the main part of which is heating and air condition (HVAC). Auxiliaries are responsible for almost half of total energy consumption (normal weather conditions) and in the winter (or hot summer) it reaches up to 70% in daily scale. The reduction of energy used for non-traction needs is currently the main challenge related to the reduction of energy demand of means of transport. It is particularly important for battery vehicles, powered from an energy source with a very limited capacity. The article presents the analysis of the influence of air temperature on the energy consumption of electric traction carried out on the basis of the real data measurement analysis. The relation between the ambient temperature and the demand for heating power was determined quantitatively. The impact of traffic delays on auxiliaries energy consumption was analyzed and it was shown, that traffic congestion can result in 60% overall energy consumption increase. Presented researches also refer to the relationship between the bus charging cycle (night charging, opportunity fast charging) and the optimal value of energy consumption, which should be assumed for energy calculations. Depending on the charging mode, the differences can reach up to 50%. In the final part of the article, different methods of optimization of non-traction needs systems were compared.

  • The resistance of S235JR steel to cavitation erosion
    • Alicja Krella
    • Dominika Zakrzewska
    • Artur Marchewicz
    2020 WEAR

    The erosion resistance of S235JR steel to flow cavitation was investigated. In order to understand an influence of steel properties and cavitation intensities on the degradation mechanisms, low-carbon S235JR steel was tested in the as-received state and after thermal treatment (annealing) under four different flow velocities. Annealing decreased steel hardness, which made S235JR steel less resistant to cavitation erosion. The performed investigations showed that the state of this steel affects the degradation process, e.g. erosion rate and development of surface roughness. An increase in flow velocity caused a linear increase in erosion rate of S235JR steel in as-received state, and an exponential increase in erosion rate of S235JR steel after thermal treatment. Regardless of the state of S235JR steel, an increase in the flow velocity caused a logarithmic increase in the area with increased roughness for Ra > 0.5 μm, where Ra parameter is the arithmetic average of all profile deviations from the mean line over the evaluation length. The increase in surface roughness and the Ra parameter depended on the flow velocity. However, for high flow rates, the Rp parameter, which is the mean of the five maximum profile peak heights from the mean line over the evaluation length, represented an effect of micro-jets impacts on the surface development better than the Ra parameter. A new parameter P, which combines elongation, impact energy and hardness, has been proposed. With increased value of this parameter, the resistance to cavitation erosion decreases. The performed investigations showed that the volume loss can be described by equation in the form of ΔV = C(t)∙(v-v0)n(t), where the function C(t) describes the development of cracks in the surface layer and the function n(t) describes the development of the hardened surface layer.

  • The Role of Electrostatics in Enzymes: Do Biomolecular Force Fields Reflect Protein Electric Fields?
    • Richard Bradshaw
    • Jacek Dziedzic
    • Chris-Kriton Skylaris
    • Jonathan Essex
    2020 Pełny tekst Journal of Chemical Information and Modeling

    Preorganization of large, directionally oriented, electric fields inside protein active sites has been proposed as a crucial contributor to catalytic mechanism in many enzymes, and it may be efficiently investigated at the atomistic level with molecular dynamics simulations. Here, we evaluate the ability of the AMOEBA polarizable force field, as well as the additive Amber ff14SB and Charmm C36m models, to describe the electric fields present inside the active site of the peptidyl-prolyl isomerase cyclophilin A. We compare the molecular mechanical electric fields to those calculated with a fully first-principles quantum mechanical (QM) representation of the protein, solvent, and ions, and find that AMOEBA consistently shows far greater correlation with the QM electric fields than either of the additive force fields tested. Catalytically relevant fields calculated with AMOEBA were typically smaller than those observed with additive potentials, but were generally consistent with an electrostatically driven mechanism for catalysis. Our results highlight the accuracy and the potential advantages of using polarizable force fields in systems where accurate electrostatics may be crucial for providing mechanistic insights.