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Gdańsk University of Technology

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  • Change in Heavy Metals Concentrations in Sediments Deposited in Retention Tanks in a Stream after a Flood
    • Nicole Nawrot
    • Karolina Matej-Łukowicz
    • Ewa Wojciechowska
    2019 Full text POLISH JOURNAL OF ENVIRONMENTAL STUDIES

    Our paper presents the results of heavy metal (HM) (Zn, Cu, Pb, Cd) content in bottom sediments from retention tanks along Oliwa Stream in Gdańsk, Poland, before a flood (BF) and after a flood (AF) 14-15 July 2016. The flood had a huge impact on the quality of bottom sediments and their displacement. The concentrations of HM differed significantly for research series conducted 3 months BF and 8 months AF. The concentration of Cu increased from 3.5 mg/kg to 88.8 mg/kg BF and from 12.1 mg/kg to 1,114.3 mg/kg AF, Zn from 27.4 mg/kg to 129.9 mg/kg BF; and 42.3 mg/kg to 244.8 mg/kg AF, Cd from 0.04 mg/kg to 0.47 mg/kg BF, and 0.08 mg/kg to 0.47 mg/kg AF. Also, the migration of some metals, mostly Cu to retention tanks located downstream, was observed, resulting from the washing away of sediments in the upper part of the stream. Since the stream inflows to the Gulf of Gdansk, urban flooding created a risk of migration of contaminants to the Baltic Sea.

  • CHANGES TAKING PLACE IN THE KINETIC ARCHITECTURE OVER THE 20TH AND 21ST CENTURIES
    • Jan Cudzik
    2019 Full text Przestrzeń i Forma

    Kinematics has accompanied architecture from its beginning and is strongly associated with its evolution. Over the centuries, it has changed form and function. However, its rank grew at the beginning of the 20th century. Along with the widespread change of the design method in the early 90s of the twentieth century, its forms have become more complex. The study showed that with the development of design techniques, this time should be treated as a breakthrough in the design of kinematic architecture.

  • Channel Blockage and Flow Maldistribution during Unsteady Flow in a Model Microchannel Plate heat Exchanger
    • Paweł Dąbrowski
    • Michał Klugmann
    • Dariusz Mikielewicz
    2019 Full text Journal of Applied Fluid Mechanics

    This paper describes the problem of channel blockage as a result of flow maldistribution between the channels of a model mini channel plate heat exchanger consisting of one pass on each leg. Each leg of the heat exchanger contains 51 parallel and rectangular minichannels of four hydraulic diameters namely 461 μm, 571 μm, 750 μm and 823 μm. In addition, a more complex geometry has been investigated where for the sake of breaking the development length the inclined transverse cuts have been incorporated. The moment of liquid phase transition through the exchanger (the working medium: water) was recorded for the mass fluxes ranging from 18.67 to 277.76 kg/m2s in 51 parallel channels with the use of a fast speed camera. The Reynolds numbers Re in the individual channels were from 10.76 to 90.04. The relationship between the mass flux and the size of the minichannels in the presence of the maldistribution is discussed here. The existence of the threshold in the mass flux below which the phenomenon occurs has been shown. Two mechanisms of channel blocking have been recorded and described in detail. A miniscale variation of one of them containing the extended geometry was created as well.

  • Characterization methods of nickel nano-particles obtained by the ex-solution process on the surface of Pr, Ni-doped SrTiO3 perovskite ceramics
    • Bartosz Kamecki
    • Tadeusz Miruszewski
    • Karolina Górnicka
    • Tomasz Klimczuk
    • Jakub Karczewski
    2019 Full text SN Applied Sciences

    In this paper, a novel electrode material based on Pr, Ni co-doped strontium titanate ( Sr0.7Pr0.3)xTi1−yNiyO3 with constant amount of 30% praseodymium dopant, different amount of nickel (y = 0.06 and y = 0.10) and additional nonstoichiometry in Sr-site (x = 1; x = 0.9 and x = 0.8) was investigated as fuel electrode for SOEC devices. A porous ceramics were prepared by solid-state reaction method. X-ray diffraction measurements revealed single phase materials with perovskite structure. Ex-solution method makes the grain surface covered by nickel nanoparticles. The influence of nickel amount, non-stoichiometry, synthesis and reduction conditions on formation of nanoparticles was investigated. Size, distribution and ability to agglomeration of Ni nanoparticles were analyzed by the scanning electron microscopy. The quantity of ex-soluted Ni particles was calculated from magnetization measurement. The total electrical conductivity of samples was measured by DC 4-wire method in the range of 100–800 °C at different atmospheres. Electrical measurements showed total electrical conductivity higher than 10 S cm−1 in a wide temperature range. All obtained results confirmed that analyzed donor and acceptor co-doped SrTiO3 materials with Ni nanoparticles after ex-solution process should be a good candidate to improve a catalysis process on fuel electrode surface.

  • Characterization of Slow and Fast Fading in Off-Body Communication at 2.45 GHz with Space Diversity Scheme in an Indoor Environment
    • Szymon Wiszniewski
    • Sławomir Ambroziak
    2019 Full text International Journal of Antennas and Propagation

    The characterization of slow and fast fading in wireless body area networks with space diversity scheme has been presented. The analysis, based on the measurements at 2.45 GHz in an indoor environment, has shown that for all investigated configurations of receiving wearable antennas, the correlation coefficient values of the received signals’ parameters are below the assumed value of 0.5, being close to zero for the vast majority of cases. It has been shown that the slow fading component may be modelled by a lognormal distribution with zero average and the standard deviation from the range of [1.43, 1.98] dB. The fast fading component is the best modelled by a Rice distribution with the noncentrality parameter and the scale parameter being in the range [0.8125, 0.9624] and [0.5269, 0.6954], respectively.

  • Characterization of slow and fast fading in off-body communication at 2.45 GHz with space diversity scheme in indoor environment
    • Szymon Wiszniewski
    • Sławomir Ambroziak
    2019

    The characterization of slow and fast fading in Wireless Body Area Networks with space diversity scheme has been presented. The analysis, based on the measurements at 2.45 GHz in indoor environment, has shown that for all investigated configurations of receiving wearable antennas the correlation coefficient values of received signals’ parameters are below the assumed value of 0.5, being close to zero for the vast majority of cases. It has been shown that the slow fading component may be modelled by a lognormal distribution with zero average and the standard deviation from the range of [1.43, 1.98] dB. The fast fading component is the best modelled by a Rice distribution with the non-centrality parameter and the scale parameter being in the range [0.8125, 0.9624], and [0.5269, 0.6954], respectively.

  • Charakterystyka elektrochemiczna odporności korozyjnej aluminium i jego stopów w wodnych środowiskach zasadowych
    • Joanna Wysocka
    2019 Full text

    Rozprawa doktorska przedstawia charakterystykę elektrochemiczną odporności korozyjnej aluminium i jego stopów w wodnych środowiskach zasadowych. Główne elementy pracy to część literaturowa, w której zarysowano problem badawczy i szczegółowo omówiono zagadnienia związane z korozją aluminium oraz, po przedstawieniu tez pracy i jej zakresu, część eksperymentalna i badawcza. Praca skupia się na kompleksowemu opisowi mechanizmów korozji aluminium. Ukazano w niej również wpływ czynników mikrostrukturalnych na kinetykę procesu degradacji, wynikającą z obecności dodatków stopowych. Główny trzon pracy opiera się na opisie roli dodatku związków nieorganicznych i organicznych w środowisku elektrolitycznym na ograniczenie degradacji stopów aluminium. Na wybranych przykładach opisano różnice dotyczące typu i liczby grup funkcyjnych występujących w obrębie analizowanej molekuły inhibitora, podjęto też próbę klasyfikacji związków o charakterze inhibitorów korozji, obecnych w obrębie złożonych mieszanin ekstraktów naturalnych. W ramach pracy zaproponowano nowatorską metodykę pomiarową do wyznaczania izoterm adsorpcji, bazującą na chwilowych pomiarach impedancji układu zmieniającego się na skutek nastrzyku inhibitora. Metodykę tę cechuje wyższa dokładność i szybkość realizacji pomiaru, a także możliwość oznaczenia granicznego stężenia inhibitora, dla którego metal pokrywa się monowarstwą adsorpcyjną.

  • CHARAKTERYSTYKA I ZAKRES STOSOWANIA TYNKÓW
    • Maciej Niedostatkiewicz
    • Tomasz Majewski
    2019 Full text Izolacje

    Wyprawy tynkarskie, potocznie nazywane tynkami, wykorzystywane są w budownictwie od wielu tysiącleci. Niektóre rodzaje tynków stosowane są w niemal niezmienionej postaci do dnia dzisiejszego, jednak wiele nowych typów wypraw tynkarskich opracowano w ciągu ostatnich kilkudziesięciu lat. Kiedyś przeważnie były przygotowywane w całości na budowie, obecnie w większości przypadków wytwarzane są w postaci suchych mieszanek, gotowych do zarobienia wodą, lub jako gotowe masy tynkarskie do ułożenia na powierzchni.

  • Charakterystyka oporności Klebsiella pneumoniae New Delhi na karbapenemy
    • Magdalena Fordon
    • Beata Krawczyk
    2019 Full text

    Bakterie Klebsiella pneumoniae New Delhi, posiadające gen oporności na karbapenemy (blaNDM) zostały po raz pierwszy wyizolowane w 2008 roku w Szwecji od pacjenta wcześniej hospitalizowanego w Indiach. Bakterie te szybko rozprzestrzeniają się po całym świecie, a od 2011 roku występują również w Polsce. Stanowią one wysokie ryzyko epidemiologiczne, ponieważ gen oporności na karbapenemy przekazywany jest pomiędzy bakteriami poprzez horyzontalny transfer genów, a międzynarodowe podróże dodatkowo sprzyjają migracji szczepów NDM-pozytywnych. Badania mające na celu ułatwienie różnicowania genetycznego tych szczepów oraz ich charakterystykę są zatem niezwykle istotne. Praca miała na celu charakterystykę oporności szczepów Klebsiella pneumoniae New Delhi na karbapenemy, z uwzględ-nieniem budowy, funkcjonowania oraz różnych wariantów enzymu za nią odpowiedzialnego.

  • Charakterystyka procesu deamonifikacji oraz rozwój technologii usuwania azotu w oparciu o ten proces
    • Dominika Grubba
    • Hussein Al Hazimi
    • Joanna Majtacz
    • Jacek Mąkinia
    2019

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  • Charakterystyka procesu utleniania stopów cyrkonu i jego wpływu na stan warstwy wierzchniej oraz desorpcję wodoru
    • Bartłomiej Trybuś
    2019 Full text

    Zjawiska degradacji tlenowej i wodorowej stopów cyrkonu mają istotne znaczenie dla modelowania mechanizmów utraty spójności koszulek paliwowych w warunkach katastrof nuklearnych, szczególnie typu LOCA. Celem naukowym pracy było poznanie i analiza zachowania utlenionych, komercyjnych stopów cyrkonu, wpływu wodoru na utlenione stopy oraz przedstawienie fizycznych źródeł i matematycznych zależności pomiędzy tymi zjawiskami. Wyniki badań kinetyki utleniania w temperaturze poniżej punktu przemiany fazowej tlenku wykazały, że stałe szybkości utleniania są dla długich czasów 15 i 48 h zgodne z parabolicznym równaniem kinetycznym, natomiast są one niższe w przypadku czasów krótkich, 0,5 i 2 h. Badania erozji wodorowej ujawniły najniższy przyrost zawartości wodoru w stopie przy najdłuższym czasie jego utleniania potwierdzając tezę, iż warstwa tlenkowa istotnie spowalnia absorpcję i dyfuzję wodoru do wnętrza stopu. Podczas awarii może dojść do gwałtownego przegrzania elementów paliwowych prowadzących do przemian fazowych oraz utraty stabilności wymiarowej. Do celów zbadania procesów zachodzących w takich warunkach użyto, nie stosowanej jak dotąd, nieniszczącej metody tomografii komputerowej. Wyniki badań warstwy tlenkowej tworzącej się w temperaturze powyżej punktu przemiany fazowej ujawniły wpływ umiejscowienia warstwy tlenkowej na koszulce cyrkonowej na kinetykę utleniania, pojawienie się efektu korozji guzowatej, powstanie odkształceń na powierzchni stopu a także pęknięć na granicy tlenek - podłoże w pobliżu tych odkształceń.

  • Charakterystyka produktów utleniania fosfolipidów oraz określenie ich wybranych aktywności biologicznych w komórkach HT29 jako modelu ludzkiego przewodu pokarmowego
    • Karol Parchem
    2019

    Wyniki licznych badań epidemiologicznych wskazują, że rodzaj, ilość oraz jakość dostarczanych wraz z pożywieniem lipidów może przyczyniać się do ograniczenia bądź rozwoju chorób dietozależnych, takich jak otyłość, cukrzyca typu 2, miażdżyca czy nadciśnienie tętnicze. Rosnące zainteresowanie określeniem wpływu lipidów dostarczanych z pożywieniem na funkcjonowanie ludzkiego organizmu wymaga przeprowadzenia licznych badań, zarówno pod kontem oznaczenia ich składu w próbkach żywności, jak i określenia ich aktywności biologicznej. Lipidami wykazującymi szczególną aktywność biologiczną, a tym samym będącymi w centrum badań lipidomicznych są fosfolipidy, a także produkty ich utlenienia. Celem niniejszej pracy doktorskiej była charakterystyka produktów enzymatycznego i termicznego utlenienia frakcji fosfolipidowej wyizolowanej z żółtka jaja kurzego, które zostało wybrane jako modelowe źródło fosfolipidów dostarczanych do organizmu z pożywieniem. W kolejnym etapie podjęto próbę określenia wpływu utlenienia fosfolipidów na kinetykę ich hydrolizy katalizowanej w wyniku aktywności trzustkowej fosfolipazy A2. Ponadto sprawdzono wpływ obecności utlenionych fosfolipidów na szybkość trawienia innych związków lipidowych, takich jak triacyloglicerole. Ostatnim celem prowadzonych badań było określenie cytotoksyczności i genotoksyczności mieszanin składających się z soli żółciowych oraz natywnych lub utlenionych fosfolipidów przed i po procesie trawienia jelitowego w warunkach in vitro. W wyniku prowadzonych prac badawczych zaproponowano metodę analizy utlenionych fosfolipidów opartą na technice dwuwymiarowej chromatografii cieczowej w trybie off-line sprzężonej z detektorem z matrycą diodową, detektorem naładowanego aerozolu oraz spektrometrem mas. Opracowana metoda została następnie wykorzystana podczas profilowania oraz identyfikacji produktów enzymatycznego i termicznego utlenienia frakcji fosfolipidowej, a także badania kinetyki tych reakcji. Utlenienie fosfolipidów przyczyniło się od zmniejszenia szybkości reakcji ich hydrolizy w wyniku aktywności fosfolipazy A2. Natomiast z drugiej strony obecność utlenionych fosfolipidów na powierzchni trawionych kropli lipidowych prowadziła prawdopodobnie do przyspieszenia reakcji hydrolizy triacylogliceroli w wyniku aktywności lipazy trzustkowej. Zarówno utlenienie, jak i hydroliza fosfolipidów w znaczący sposób wpływały na ich aktywność biologiczną.

  • Charge density wave and large nonsaturating magnetoresistance in YNiC2 and LuNiC2
    • Kamil Kolincio
    • Marta Roman
    • Tomasz Klimczuk
    2019 Full text PHYSICAL REVIEW B

    We report a study of physical properties of two quasi-low-dimensional metals YNiC2 and LuNiC2 including the investigation of transport, magnetotransport, galvanomagnetic, and specific heat properties. In YNiC2 we reveal two subsequent transitions associated with the formation of weakly coupled charge density wave at TCDW=318K and its locking in with the lattice at T1=275K. These characteristic temperatures follow the previously proposed linear scaling with the unit cell volume, demonstrating its validity extended beyond the lanthanide-based RNiC2. We also find that, in the absence of magnetic ordering able to interrupt the development of charge density wave, the Fermi surface nesting leads to opening of small pockets, containing high-mobility carriers. This effect gives rise to substantial enhancement of magnetoresistance, reaching 470% for YNiC2 and 50% for LuNiC2 at T=1.9K and B=9T.

  • Charge Transfer, Complexes Formation and Furan Fragmentation Induced by Collisions with Low-Energy Helium Cations
    • Tomasz Wąsowicz
    • Marta Łabuda
    • Boguslaw Pranszke
    2019 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    The present work focuses on unraveling the collisional processes leading to the fragmentation of the gas-phase furan molecules under the He+ and He2+ cations impact in the energy range 5–2000 eV. The presence of different mechanisms was identified by the analysis of the optical fragmentation spectra measured using the collision-induced emission spectroscopy (CIES) in conjunction with the ab initio calculations. The measurements of the fragmentation spectra of furan were performed at the different kinetic energies of both cations. In consequence, several excited products were identified by their luminescence. Among them, the emission of helium atoms excited to the 1s4d1D2,3D1,2,3 states was recorded. The structure of the furan molecule lacks an He atom. Therefore, observation of its emission lines is spectroscopic evidence of an impact reaction occurring via relocation of the electronic charge between interacting entities. Moreover, the recorded spectra revealed significant variations of relative band intensities of the products along with the change of the projectile charge and its velocity. In particular, at lower velocities of He+, the relative cross-sections of dissociation products have prominent resonance-like maxima. In order to elucidate the experimental results, the calculations have been performed by using a high level of quantum chemistry methods. The calculations showed that in both impact systems two collisional processes preceded fragmentation. The first one is an electron transfer from furan molecules to cations that leads to the neutralization and further excitation of the cations. The second mechanism starts from the formation of the He−C4H4O+/2+ temporary clusters before decomposition, and it is responsible for the appearance of the narrow resonances in the relative cross-section curves

  • Chemical and Mechanical Properties of 70-Year-Old Concrete
    • Andrzej Ambroziak
    • Elżbieta Haustein
    • Jarosław Kondrat
    2019 Full text JOURNAL OF MATERIALS IN CIVIL ENGINEERING

    The aim of this research is to determine the durability and strength of concrete continuous footing based on the chosen mechanical, physical, and chemical properties of the concrete. The presented investigations constitute some opinions from experts on the bearing capacity of concrete continuous footing and the possibilities of carrying additional loads and extended working life. The cylindrical specimens were taken from continuous footing by a concrete core bore hole diamond drill machine. The properties of old concrete are compared with present and old standard requirements and guidelines. Large dispersions of the cylindrical compressive strength (6.9–29.3 MPa), density (1,750–2,100  kg/m3), and water absorption (5%–14%) were observed. A short literature survey concerning old concrete properties is also given.

  • Chemical Aspects of Biological Activity of Isothiocyanates and Indoles, the Products of Glucosinolate Decomposition
    • Dominik Kołodziejski
    • Izabela Koss-Mikołajczyk
    • Ahmad Yaman Abdin
    • Jacob Claus
    • Agnieszka Bartoszek-Pączkowska
    2019 Full text CURRENT PHARMACEUTICAL DESIGN

    There is growing evidence that cancer chemoprevention employing natural, bioactive compounds may halt or at least slow down the different stages of carcinogenesis. A particularly advantageous effect is attributed to derivatives of sulfur-organic phytochemicals, such as glucosinolates (GLs) synthesized mainly in Brassicaceae plant family. GLs are hydrolysed enzymatically to bioactive isothiocyanates (ITC) and indoles, which exhibit strong anti-inflammatory and anti-carcinogenic activity. Highly bioavailable electrophilic ITC are of particular interest, as they can react with nucleophilic groups of important biomolecules to form dithiocarbamates, thiocarbamates and thioureas. These modifications seem responsible for the chemopreventive activity, but also for genotoxicity and mutagenicity. It was documented that ITC can permanently bind to important biomolecules such as glutathione, cytoskeleton proteins, transcription factors NF-κB and Nrf2, thiol-disulfide oxidoreductases, proteasome proteins or heat shock proteins. Furthermore, ITC may also affect epigenetic regulation of gene expression, e.g. by inhibition of histone deacetylases. Some other derivatives of glucosinolates, especially indoles, are able to form covalent bonds with nucleobases in DNA, which may result in genotoxicity and mutagenicity. This article summarizes the current state of knowledge about glucosinolates and their degradation products in terms of possible interactions with reactive groups of cellular molecules.

  • Chemical structures, rheological and physical properties of biopolyols prepared via solvothermal liquefaction of Enteromorpha and Zostera marina biomass
    • Paulina Kosmela
    • Kamila Gosz
    • Paweł Kazimierski
    • Aleksander Hejna
    • Józef Haponiuk
    • Łukasz Piszczyk
    2019 Full text CELLULOSE

    In this work, liquefied biomass from the Baltic Sea was used for the preparation of rigid polyurethane (PUR) foams. The biomass contained 10 wt% of Enteromorpha macroalgae and 90 wt% of Zostera marina seagrass characterized by a high content of cellulose. The influence of time, temperature and the type of solvent on the efficiency of the liquefaction process and properties of biopolyols was determined. Obtained materials were analyzed in terms of chemical structure, rheological properties, thermal stability and basic physical and mechanical properties. It was found that optimal parameters for liquefaction of used biomass were: temperature of 150 °C, reaction time of 6 h and a solvent mixture containing glycerol and poly(ethylene glycol) in ratio of 50:50 (biopolyol 50G50P_150). Under these conditions, 78 wt% of biomass was liquefied and resulting biopolyol was characterized by a hydroxyl number of 650 mg KOH/g. Depending on the used solvent mixture and the liquefaction temperature, biopolyols showed the character of Newtonian or non-Newtonian liquids. Rigid PUR foams were obtained by substitution of petrochemical polyol with 10, 20 and 30 wt% of biopolyol. It was found that the addition of biopolyol to foams’ formulations did not cause significant changes in their chemical structure, while mechanical strength and thermal stability were enhanced. The presented study confirms that biomass from the Baltic Sea can be used for the synthesis of biopolyols and rigid polyurethane foams.

  • Chemical variability of Rhododendron tomentosum (Ledum palustre) essential oils and their pro-apoptotic effect on lymphocytes and rheumatoid arthritis synoviocytes
    • Anna Jesionek
    • Adam Kokotkiewicz
    • Anna Mikosik-Roczynska
    • Klaudia Ciesielska-Figlon
    • Piotr Luczkiewicz
    • Adam Bucinski
    • Agnieszka Daca
    • Jacek M. Witkowski
    • Ewa Bryl
    • Bożena Zabiegała
    • Maria Luczkiewicz
    2019 Full text FITOTERAPIA

    Rhododendron tomentosum (Ledum palustre) is an aromatic plant traditionally used for alleviating rheumatic complaints which makes it a potential candidate for a natural drug in rheumatoid arthritis (RA) treatment. However, the effects of plants’ volatiles on apoptosis of synovial fibroblasts and infiltrating leucocytes of RA synovia, have not been reported. Volatile fraction of R. tomentosum is chemically variable and chemotypes of the plants need to be defined if the oil is to be used for therapeutic purposes. In the presented work, cluster analysis of literature data enabled to define 10 chemotypes of the plant. The volatile fractions of known composition were then tested for bioactivity using a RA-specific in vitro models. Essential oils of two wild types (γ-terpineol and palustrol/ledol type) and one in vitro chemotype (ledene oxide type) were obtained by hydrodistillation and their bioactivity was tested in two in vitro models: I - peripheral blood lymphocytes of healthy volunteers and II - synoviocytes and immune cells isolated from synovia of RA patients. The influence of oils on blood lymphocytes’ proliferation and apoptosis rates of synovia-derived cells was determined by flow cytometry. Dose-dependent inhibitory effect of the serial dilutions of R. tomentosum oils on proliferation rates of blood lymphocytes was found. At 1:400 dilutions, all the tested oils increased the number of necrotic cells in synovial fibroblasts from RA synovia. Additionally, increased proportions of late apoptotic cells were observed in leucocyte populations subjected to oils at 1:400 dilution.

  • Chemometrics and Statistics | Multicriteria Decision Making
    • Marta Bystrzanowska
    • Marek Tobiszewski
    2019

    This contribution describes the application of Multicriteria Decision Making tools in analytical chemistry. The general scheme of MCDM is presented to show its general steps. The most frequently applied in analytical sciences MCDM techniques – AHP, ELECTRE, PROMETHEE and TOPSIS – are briefly described and their advantages and disadvantages are discussed. The applications in analytical chemistry are selection of an appropriate analytical procedure and optimization of analytical processes. MCDM techniques are also applied to select analytical reagents according to their environmental impact, human health and safety issues – solvents and derivatization agents are assessed in this way.

  • Chitosan and polyvinyl alcohol nanocomposites with cellulose nanofibers from ginger rhizomes and its antimicrobial activities
    • Joby Jacob
    • Gregary Peter
    • Sabu Thomas
    • Józef Haponiuk
    • Sreeraj Gopi
    2019 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES

    The inhibitory effect of 5% GNF bionanocomposites against Bacillus cereus, Escherichia coli, Staphylococcus aureus and Salmonella typhimurium indicated good antibacterial activity of the nanocomposites due to the addition of GNF in the biopolymer matrices. The use of GNF will help to increase the economic values of agricultural waste and the characteristic properties of GNF derived bionanocomposites could be possibly used in medical and packaging areas.

  • Chromatgrafia cieczowa. Teoria i praktyka
    • Waldemar Wardencki
    • Zygfryd Witkiewicz
    • Irena Malinowska
    2019

    Książka zawiera całokształt wiedzy dotyczącej chromatografii ciecvzowej - kolumnowej i cienkowarstwowej. Opisane zostały wszystkie techniki chromatografii cieczowej, zarówno w zakresie teorii chromatografii, jak i praktycznych zastosowań.

  • Ciecze jonowe jako medium sorpcyjne w mikroekstrakcji do pojedynczej kropli Cz. I. Podstawy teoretyczne zagadnienia
    • Karolina Konieczna
    • Łukasz Marcinkowski
    • Adam Kloskowski
    • Jacek Namieśnik
    2019 Analityka: Nauka i Praktyka

    Technika mikroekstrakcji do pojedynczej kropli stanowi sztandarowy przykład rozwiązania technicznego spełniającego wymogi stawiane przez ideę zielonej chemii analitycznej.

  • Ciecze jonowe jako medium sorpcyjne w mikroekstrakcji do pojedynczej kropli. Cz.II. Praktyka analityczna
    • Karolina Konieczna
    • Łukasz Marcinkowski
    • Adam Kloskowski
    • Jacek Namieśnik
    2019 Analityka: Nauka i Praktyka

    Pomimo rosnącego zainteresowania metodami analitycznymi opartymi na użyciu cieczy jonowych ich sprzężenie wraz z techniką mikroekstrakcji do pojedynczej kropli nie osiągnęło zadowalającej popularności oraz akceptacji ze strony środowiska naukowego.

  • City walk: a didactic innovative experiment in architectural education
    • Justyna Borucka
    2019 Full text World Transactions on Engineering and Technology Education

    Walking is an activity that involves studying physical space and requires careful observation to be immersed in the surrounding reality. City walks are popular ways of encountering an urban space, spatial relation, its history, and recognising the problems and needs of space users, as well as future development of the city. City walks also may be educationally p owerful: the exploration of certain city spaces and their associated narratives. The aim of this article is to present a city walk as an experimental tool in architectural education, in particular as a method of critical engagement with city problems and the needs of its users. City walks are an experiment, a method of studying spatial relations to raise the awareness of future architects and urban planners. The question arising from the researchconcerns the role that urban walks can play in creating the spatial and critical involvement of future architects and urban planners. The study was based on city walk experiments conducted by the Faculty of Architecture at Gdańsk University of Technology (GUT), Gdańsk, Poland, in collaboration with a number of partner.

  • CIVILIZING THE PUBLIC PARTICIPATION PRACTICE IN POST-TRANSITION COUNTRIES
    • Piotr Lorens
    2019 Full text IOP Conference Series: Materials Science and Engineering

    The phenomenon of public participation is not so new to both planning theory and practice. In fact, involving local community in the decision-making process regarding local urban development directions is widely discussed and a number of various forms of these are being introduced. This paper deals with a number of

  • Clarke duality for Hamiltonian systems with nonstandard growth
    • S Acinas
    • Jakub Maksymiuk
    • F Mazzone
    2019 Full text NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS

    We consider the existence of periodic solutions to Hamiltonian systems with growth conditions involving G-function. We introduce the notion of symplectic G-function and provide relation for the growth of Hamiltonian in terms of certain constant CG associated to symplectic G-function G. We discuss an optimality of this constant for some special cases. We also provide applications to the Φ-laplacian type systems.

  • Classification of objects in the LIDAR point clouds using Deep Neural Networks based on the PointNet model
    • Zdzisław Kowalczuk
    • Karol Szymański
    2019 Full text IFAC-PapersOnLine

    This work attempts to meet the challenges associated with the classification of LIDAR point clouds by means of deep learning. In addition to achieving high accuracy, the designed system should allow the classification of point clouds covering an area of several dozen square kilometers within a reasonable time interval. Therefore, it must be characterized by fast processing and efficient use of memory. Thus, the most popular approaches to the point cloud classification using neural networks are discussed. At the same time, their shortcomings are indicated. A developed model based on the PointNet architecture is presented and the way of preparing data for classification is shown. The model is tested on a cloud coming from the 3D Semantic Labeling competition, achieving a good result, confirmed by the high quality of the system, i.e. a high rate of categorization of objects.

  • Classification of Urban Regeneration Participants as a Basis for Identification of Construction Investment's Risk Sources
    • Magdalena Apollo
    2019 Full text IOP Conference Series: Materials Science and Engineering

    On the basis of the conducted research it can be concluded that the majority of the existing urban regeneration problems are revealed by the lack of an in-depth analysis of sources and risk factors. For the above reasons, the subject of this study is classification of urban regeneration's participants as a basis for identification of construction investment's risk sources. The research methodology is based on an in-depth analysis of the available documentation of four urban regeneration projects implemented in Gdańsk, which was confronted with the provisions of the Regeneration Act. The conducted analysis allowed to clearly classify the participants of urban regeneration process, also indicating its direct and indirect beneficiaries. As a consequence, the elaboration defines the responsibility of participants in the investment process, and at the same time allows to divide the risk between individual entities implementing activities covered by the intervention area. The observations described in the article also concern shortcomings in the documentation including, among others, lack of the definition of the required experience of design units depending on the nature of the construction works being carried out.

  • Clearing directed subgraphs by mobile agents
    • Dariusz Dereniowski
    • Andrzej Lingas
    • Dorota Osula
    • Mia Persson
    • Paweł Żyliński
    2019 Full text JOURNAL OF COMPUTER AND SYSTEM SCIENCES

    We study several problems of clearing subgraphs by mobile agents in digraphs. The agents can move only along directed walks of a digraph and, depending on the variant, their initial positions may be pre-specified. In general, for a given subset S of vertices of a digraph D and a positive integer k, the objective is to determine whether there is a subgraph H=(V,A) of D such that (a) S is a subset of V, (b) H is the union of k directed walks in D, and (c) the underlying graph of H includes a Steiner tree for S in D. Since a directed walk is a not necessarily a simple directed path, the problem is actually on covering with paths. We provide several results on the polynomial time tractability, hardness, and parameterized complexity of the problem. Our main fixed-parameter algorithm is randomized.

  • Client-side versus server-side geographic data processing performance comparison: Data and code
    • Marcin Kulawiak
    2019 Full text Data in Brief

    The data and code presented in this article are related to the research article entitled “Analysis of Server-side and Client-side Web-GIS data processing methods on the example of JTS and JSTS using open data from OSM and Geoportal” (Kulawiak et al., 2019). The provided 12 datasets include multi-point and multi-polygon data of different scales and volumes, representing real-world geographic features. The datasets cover the area of Tricity in northern Poland as well as Polish Exclusive Economic Zone of the Baltic Sea. They have been converted to a common Spherical Mercator projection coordinate system (EPSG:3857) and consist of vector features without attributes. They are provided in the form of single GeoJSON files containing multi-feature objects which can be processed by client-side as well as server-side algorithms in a single request. The provided javascript code exemplifies the application of those datasets for measurement of client-side and server-side geoprocessing performance by using algorithms implemented as part of Java Topology Suite (JTS) and Javascript Topology Suite (JSTS). The combination of data and code samples constitutes a universal benchmark for investigative analysis of geographic data processing algorithms and their implementations in different software system architectures.

  • Combination of air-dispersion cathode with sacrificial iron anode generating Fe2+Fe3+2O4 nanostructures to degrade paracetamol under ultrasonic irradiation
    • Reza Mirzaee
    • Reza Darvishi
    • Alireza Khataee
    • Grzegorz Boczkaj
    2019 Full text JOURNAL OF MOLECULAR LIQUIDS

    In the present study, ultrasound (US) was coupled with an electrochemical process (ECP) consisting of a novel cathode of carbon cloth (CC)-carbon black (CB) as the nano-composite air-dispersion cathode (NADC) for the degradation of paracetamol (APAP) in an aquatic medium. The NADC favored in situ production of H2O2 by the cathodic reduction. The implementation of iron sacrificial anode instead of dimensionally stable anodes resulted in the generation of Fe2+Fe3+2O4 nanostructures in the solution. The Fe2+Fe3+2O4 nanostructures were activated by means of both US and H2O2 to produce more OH in the aqueous solution. In addition, the utilization of US caused the conversion of H2O2 to OH irrespective of free oxidizing radicals generated through cavitation phenomenon. The hybrid method based on coupling US and NADC-ECP in the presence of Fe2+Fe3+2O4 nanostructures proved synergism (39.8%) allowing to effective decomposition of APAP. The pulse mode of US enhanced the degradation efficiency of APAP as compared to the sweep and normal modes. The intermediates of the degradation route were identified using GC–MS analysis as well as mineralization efficiency. The toxicity assay was also performed based on the inhibition test using activated sludge of a biological wastewater treatment plant.

  • Combined Close Range Photogrammetry and Terrestrial Laser Scanning for Ship Hull Modelling
    • Paweł Burdziakowski
    • Paweł Tysiąc
    2019 Full text Geosciences

    The paper addresses the fields of combined close-range photogrammetry and terrestrial laser scanning in the light of ship modelling. The authors pointed out precision and measurement accuracy due to their possible complex application for ship hulls inventories. Due to prescribed vitality of every ship structure, it is crucial to prepare documentation to support the vessel processes. The presented methods are directed, combined photogrammetric techniques in ship hull inventory due to submarines. The class of photogrammetry techniques based on high quality photos are supposed to be relevant techniques of the inventories’ purpose. An innovative approach combines these methods with Terrestrial Laser Scanning. The process stages of data acquisition, post-processing, and result analysis are presented and discussed due to market requirements. Advantages and disadvantages of the applied methods are presented.

  • Combining Road Network Data from OpenStreetMap with an Authoritative Database
    • Grzegorz Szwoch
    2019 Full text Journal of Transportation Engineering, Part A: Systems

    Computer modeling of road networks requires detailed and up-to-date dataset. This paper proposes a method of combining authoritative databases with OpenStreetMap (OSM) system. The complete route is established by finding paths in the graph constructed from partial data obtained from OSM. In order to correlate data from both sources, a method of coordinate conversion is proposed. The algorithm queries road data from OSM and provides means of locating any point on the route in both datasets. A method of calculating the distance of any route point from the origin, and conversion between the distance and geographic coordinates, is described. Next, the location of any route point in the authoritative database is converted to the calculated route distance, which establishes a relation between the two data sources. Additionally, a method of estimating road curvature is proposed. The algorithm is validated in series of experiments. The proposed algorithm may be beneficial for researchers who collect datasets needed for computer simulations, e.g. for evaluation of optimal speed limits, and it shows usefulness of OSM in transportation related research.

  • Communication and Documentation Practices in Agile Requirements Engineering: A Survey in Polish Software Industry
    • Aleksander Jarzębowicz
    • Natalia Sitko
    2019 Full text Lecture Notes in Business Information Processing

    Requirements engineering, system analysis and other analytical activities form the basis of every IT project. Such activities are not clearly defined in Agile development methods, but it does not mean that they are absent in an agile project. The aim of our work was to determine which practices related to requirements-related communication and which requirements documenting techniques are used in agile software projects. For this reason we carried out a survey study targeting agile practitioners from Polish IT industry. The paper presents survey results, discusses the noticed differences with respect to the general Agile values and principles and provides a comparison to results of similar studies described in the related work. The main observation about communication practices is that frequent, face to face communication is the most common, but many respondents also declare use of other, remote communication means or exchanging SRS documents. The investigation of requirements documentation techniques revealed differences between the techniques used while describing requirements for developers and those used to elicit requirements from stakeholders and to comprehend them.

  • Comparative analysis of earthships and conventional buildings in terms of investment and operating costs
    • Dominika Grubba
    2019

    The aim of the master's thesis is to present the idea of earthships and compare them with conventional buildings in terms of investment and operating costs. Earthships are buildings erected from tires and other wastes whose characteristic feature is their self-sufficiency. The first part of the master's thesis is to discuss the basic issues related to the earthship building. The beginnings of tire homes and their development are discussed, as well as six elements on which their concept is based: material recycling, solar heating / thermal mass, electricity, water extraction, wastewater treatment and food production. There are also described the next stages of building the earthship, as well as examples from Europe and the world. The second part of the master thesis concerns the comparative analysis of earthships and conventional buildings. The costs of construction of both types of buildings and the costs of use related to heating of houses, use of water and electricity were given. After calculations, it can be observed that investment costs are comparable in both cases. Exploitation, in turn, is definitely cheaper in earthships. If it were not for problems with building regulations and the non-universality of the Reynold’s global model, there would surely be more earthships around the world.

  • COMPARATIVE EVALUATION OF FERRITE SHIELDING DESIGNS IN INDUCTIVE POWER TRANSFER SYSTEMS
    • Bohdan Pakhaliuk
    • Paweł Derkacz
    2019

    Wireless power transfer technology is becoming widespread in last few years. In comparison to conventional solutions this technology can significantly increase maintainability and safety of charging systems. From the other side there are list of factors that limit efficiency of wireless systems. One of them is low coupling between coils caused by comparably high leakage inductance in comparison to regular transformer.

  • Comparative Evaluation of Multicoil Inductive Power Transfer Approaches Based on Z-source Network
    • Bohdan Pakhaliuk
    • Oleksandr Husev
    • Ryszard Strzelecki
    • Viktor Shevchenko
    • Khomenko Maksym
    2019

    This paper describes comparative evaluation between wireless power transfer topologies with utilization of Z-source network. Paper describes components calculation method. List of open-loop, close-loop simulations were conducted to compare both topologies. Spectrum of signals is also researched.

  • Comparative Evaluation of Selected Biological Methods for the Removal of Hydrophilic and Hydrophobic Odorous VOCs from Air
    • Milena Gospodarek
    • Piotr Rybarczyk
    • Bartosz Szulczyński
    • Jacek Gębicki
    2019 Full text Processes

    Due to increasingly stringent legal regulations as well as increasing social awareness, the removal of odorous volatile organic compounds (VOCs) from air is gaining importance. This paper presents the strategy to compare selected biological methods intended for the removal of different air pollutants, especially of odorous character. Biofiltration, biotrickling filtration and bioscrubbing technologies are evaluated in terms of their suitability for the effective removal of either hydrophilic or hydrophobic VOCs as well as typical inorganic odorous compounds. A pairwise comparison model was used to assess the performance of selected biological processes of air treatment. Process efficiency, economic, technical and environmental aspects of the treatment methods are taken into consideration. The results of the calculations reveal that biotrickling filtration is the most efficient method for the removal of hydrophilic VOCs while biofilters enable the most efficient removal of hydrophobic VOCs. Additionally, a simple approach for preliminary method selection based on a decision tree is proposed. The presented evaluation strategies may be especially helpful when considering the treatment strategy for air polluted with various types of odorous compounds.

  • Comparative Greenness Evaluation
    • Marta Bystrzanowska
    • Aleksander Orłowski
    • Marek Tobiszewski
    2019

    Greenness of analytical procedure is multivariable aspect as many greenness criteria should be taken into consideration. On the other hand, modern analytical chemistry offers dozens of analytical procedures, based on different sample preparation and final determination techniques that are used for the determination of a given analyte in a given matrix. For such complex decision-making processes, multi-criteria decision analysis tools are applied as a systematic approach to deal with complex decisions. Multi-criteria decision analysis can be treated as green analytical chemistry comparative metric tool if criteria of assessment describe procedures greenness. In this contribution, we present the results of ranking of seven analytical procedures that are used for the determination of benzo[a]pyrene in smoked food products. The results of TOPSIS, AHP, PROMETHEE application indicate that the first rank is scored by microwave-assisted extraction followed by high-performance liquid chromatography with spectrofluorometric detection, indicating this procedure as the greenest alternative. The contribution describes a step-by-step approach to the application of three multi-criteria decision analysis tools as green analytical chemistry metrics systems.

  • Comparative Study of Balancing SRT by Using Modified ASM2d in Control and Operation Strategy at Full-Scale WWTP
    • Jakub Drewnowski
    • Jacek Mąkinia
    • Aleksandra Szaja
    • Grzegorz Łagód
    • Łukasz Kopeć
    • José Alonso Aguilar
    2019 Full text Water

    Detailed knowledge on the composition of the influent going into the wastewater treatment system is essential for the development of a reliable computer model. In the context of WWTPs (wastewater treatment plants), the wastewater characteristics are not only important for activated sludge system modelling, but also have an impact on the appropriate control of single unit operations. The aim of this study was to evaluate the concepts of COD (chemical oxygen demand) fractionation measurement in municipal wastewater with a respirometric method in control, and modelling the biological treatment processes at WWTP using the modified Activated Sludge Model no. 2d (ASM2d) developed by Drewnowski and Makinia. The batch OUR (oxygen uptake rate) test results and COD measurements obtained at BNR plant (96,000 m3/d) in Gdansk (Poland), were compared and evaluated with the main BNR (biological nutrient removal) WWTP (144,000 m3/d) located in Malaga (Spain). Respirometric tests and COD fractionation provided the experimental database for the comparison of the wastewater characteristics and model predictions at both large WWTPs. Some parameters, such as the heterotrophic growth yield (YH) coefficient, required calibration/validation of the range (YH = 0.64 and 0.74 gCOD/gCOD for Gda´nsk and Malaga WWTP, respectively) to fit the modified ASM2d. The crucial issue when dealing with the newly developed model and proposed wastewater characterization for both study plants were extremely low and high values of the XS/XI ratio, which can be used to control full-scale WWTP and balance the solid retention time (SRT) in activated sludge systems.

  • Comparative Study of Iranian Nomadic Housing
    • Najmeh Hassas
    • Justyna Borucka
    2019 Full text ISVS e-journal

    The purpose of this paper is to present the typical domestic space and to describe and analyze a particular temporary architecture (nomadic house) in order to perceive the exceptional nomadic culture and the architecture associated with it. The research investigates some of the nomadic tribes of Iran and their living space: including the nomadic home (Black Tent) and, uses those findings to analyze their unique culture. The research is a comparative study of the nomadic housing of Iranian tribes. Rediscovering different architecture of nomadic people who need migration between their summer and winter residences, who need places for their livestock and therefore who need different methods of living helps to understand this particular modus vivendi. In this regard, documenting how Iranian tribes can arrange and design their homes seems to be a good method for the preservation of this culture

  • Comparative study on the effectiveness of various types of road traffic intensity detectors
    • Andrzej Czyżewski
    • Andrzej Sroczynski
    • Tomasz Smialkowski
    • Piotr Hoffmann
    • Sebastian Cygert
    • Grzegorz Szwoch
    • Józef Kotus
    • Dawid Weber
    • Maciej Szczodrak
    • Damian Koszewski
    • Kazimierz Jamroz
    • Wojciech Kustra
    2019

    Vehicle detection and speed measurements are crucial tasks in traffic monitoring systems. In this work, we focus on several types of electronic sensors, operating on different physical principles in order to compare their effectiveness in real traffic conditions. Commercial solutions are based on road tubes, microwave sensors, LiDARs, and video cameras. Distributed traffic monitoring systems require a high number of monitoring stations. In order to improve the accuracy of traffic monitoring, several modalities, complementing each other, may be used in the monitoring stations. In this paper, we propose a multimodal approach to traffic monitoring, using sensors and signal processing algorithms developed specifically for the described task. The aim of the work described here is to test each modality in a real-life scenario, assess their accuracy and to evaluate their usefulness for multimodal traffic monitoring stations. The modalities described in the paper are: Doppler sensor with custom signal processing, video analysis based on cameras and neural networks (employing deep learning algorithms), audio monitoring based on an acoustic vector sensor developed by the authors, as well as LiDAR and Bluetooth as supplementary means of traffic monitoring. Additionally, road tubes and a commercial video-based monitoring system were used in order to provide reference data. Consequently, we can present in this paper a comparative study on the effectiveness of traffic sensors operating based on different principles of work.

  • Comparison of AHP and Numerical Taxonomy Methods Based on Biogas Plant Location Analysis
    • Alicja Stoltmann
    • Paweł Bućko
    2019 Full text Acta Energetica

    The paper presents a comparison of the multi-criteria Analytic Hierarchy Process (AHP) method and numerical taxonomy in biogas plant location selection. Biogas plants are sources that will significantly contribute to the implementation of the provisions of the energy and climate package for Poland by 2030. Increasing the share of energy produced from renewable sources, e.g. biogas plants, will increase the country’s energy security. Biogas plants obtain energy from biogas of various origins. Therefore, biogas plant location choice depends on such factors as environmental impact, biogas availability and origin, technological aspects, and possible output energy use. The multitude of these factors makes the biogas plant location choice a multithreaded issue. The AHP is a highly sophisticated mathematical method. Its advantage is the ability to compare countable and uncountable factors with each other. The analysis outcome is a vector containing the ranking of considered variants. The numerical taxonomy is a much less complex method. It consists in determining the tested solutions’ distances from a hypothetical ideal solution, the so-called standard, in effect creating their ranking. The methods were compared in terms of sensitivity to change of decision options and criteria, decision-makers’ and experts’ involvement level, as well as computational complexity.

  • Comparison of anti-plane surface waves in strain-gradient materials and materials with surface stresses
    • Victor Eremeev
    • Giuseppe Rosi
    • Salah Naili
    2019 Full text MATHEMATICS AND MECHANICS OF SOLIDS

    Here we discuss the similarities and differences in anti-plane surface wave propagation in an elastic half-space within the framework of the theories of Gurtin–Murdoch surface elasticity and Toupin–Mindlin strain-gradient elasticity. The qualitative behaviour of the dispersion curves and the decay of the obtained solutions are quite similar. On the other hand, we show that the solutions relating to the surface elasticity model are more localised near the free surface. For the strain-gradient elasticity model there is a range of wavenumbers where the amplitude of displacements decays very slowly.

  • Comparison of Compact Reduced Basis Method with Different Model Order Reduction Techniques
    • Damian Szypulski
    • Grzegorz Fotyga
    • Valentin De La Rubia
    • Michał Mrozowski
    2019

    Different strategies suitable to compare the performance of different model order reduction techniques for fast frequency sweep in finite element analysis in Electromagnetics are proposed and studied in this work. A Frobenius norm error measure is used to describe how good job a reduced-order model is doing with respect to the true system response. In addition, the transfer function correct behavior is monitored by studying the convergence of the poles and zeros of the reduced-order system. The results of this comparison are detailed in two microwave filter structures.

  • Comparison of Different Measurement Techniques as Methodology for Surveying and Monitoring Stainless Steel Chimneys
    • Karol Daliga
    • Zygmunt Kurałowicz
    2019 Full text Geosciences

    The measurement of a chimney axis is an engineering geodesy task. These measurements allow to assess the technical condition of chimneys and are usually carried out for reinforced concrete chimneys. When measuring high chimneys, the main problem may be the need to go a long distance to take a measurement. The surface of the chimney can also be problematic because it can absorb so much light from the range finder that total station reflectorless measurement or laser scanning will not be possible or will be affected by significant error. Chimneys made of stainless steel are also used today. They are not as high as reinforced concrete chimneys, but measuring them using reflectorless total stations or laser scanning can also be problematic. Problems arise from the reflective surface of these chimneys. The article presents a comparison of measurement results of a stainless steel chimney fragment obtained from total station measurement and laser scanning. Similarities and differences in the obtained axis of this chimney fragment are presented.

  • Comparison of GC–MS and MEKC methods for caffeine determination in preworkout supplements
    • Emilia Waraksa
    • Andrzej Pokrywka
    • Marek Konop
    • Jacek Namieśnik
    • Ewa Kłodzińska
    2019 ELECTROPHORESIS

    In this study, GC–MS- and MEKC-based methods for determination of caffeine (CAF) in preworkout supplements were developed and validated. The proposed protocols utilized minimal sample preparation (simple dilution and syringe filtration). The developed methods achieved satisfactory validation parameters, i.e. good linearity (R2 0.9988 and R2 0.9985 for GC–MS- and MEKC-based method, respectively), satisfactory intraand interaccuracy (within 92.6–100.7% for method utilizing GC–MS and 92.1–110.3% for protocol based on MEKC) and precision (CV 15.9% and CV 6.3% for GC– MS- and MEKC-based method, respectively) and recovery (within 100.1–100.8% for method utilizing GC–MS and 101.5–106.2% for protocol based on MEKC). The LOD was 0.03 and 3 g/mL formethod utilizing GC–MS andMEKC, respectively. The CAF concentrations determined by GC–MS- and MEKC-based methods were found to be in the range of 8.53–11.23 and 8.20–11.61 g/mL, respectively. Taking into consideration information on the labels, the investigated supplements were found to contain from 110.0 to 167.3% of the declared CAF content, which confirmed the literature reports on incompatibility of the declared product compositions with real ones. Nevertheless, the consumption of examined supplements as recommended by producers did not lead to exceeding the CAF safe limit of 400 mg per day. Additionally, the MEKC-based method allowed for detection and identification of vitamin B3 and B6 in all of the investigated supplement samples, which demonstrated that MEKC-based protocols may be an appropriate assays for simultaneous determination of CAF and vitamins.

  • Comparison of Lithuanian and Polish Consonant Phonemes Based on Acoustic Analysis – Preliminary Results
    • Grazina Korvel
    • Olga Kurasova
    • Bożena Kostek
    2019 Full text Archives of Acoustics

    The goal of this research is to find a set of acoustic parameters that are related to differences between Polish and Lithuanian language consonants. In order to identify these differences, an acoustic analysis is performed, and the phoneme sounds are described as the vectors of acoustic parameters. Parameters known from the speech domain as well as those from the music information retrieval area are employed. These parameters are time- and frequency-domain descriptors. English language as an auxiliary language is used in the experiments. In the first part of the experiments, an analysis of Lithuanian and Polish language samples is carried out, features are extracted, and the most discriminating ones are determined. In the second part of the experiments, automatic classification of Lithuanian/English, Polish/English, and Lithuanian/Polish phonemes is performed.

  • Comparison of pavement noise properties on selected road sections using different CPX measuring systems: self-powered vehicle and special test trailer
    • Piotr Mioduszewski
    • Wojciech Sorociak,
    2019 Full text

    The recently published ISO standard intended to measure the noise properties of road surfaces in a standardized method (ISO 11819-2:2017) precisely defines measurement procedure of the influence of road surface on traffic noise. According to it, two types of test vehicles may be utilized: a self-powered vehicle fitted with one or more test tyres and a trailer towed by a separate vehicle with one or more test tyres mounted on the trailer. The microphones are located in the close-proximity of the test tyre in strictly defined positions. Round Robin Test using both types of test vehicles was carried out in Poland. The objective was the comparison of noise properties of selected pavements in terms of noise levels obtained when using different CPX measuring systems and to determine if pavement ranking regarding the noise properties is the same. Twelve road sections of six different wearing course mixes were selected for this purpose. Measurements were performed by two independent teams operating two different CPX measuring systems equipped with different test tyres. The RRT results show significant differences in CPX noise levels ranging from –0.9 to +2.3 dB. The pavement ranking is generally the same with some exceptions for less noisy road surfaces.

  • Comparison of Properties of the Hybrid and Bilayer MWCNTs—Hydroxyapatite Coatings on Ti Alloy
    • Beata Majkowska-Marzec
    • Rogala-Wielgus Dorota
    • Michał Bartmański
    • Bartosewicz Bartosz
    • Andrzej Zieliński
    2019 Full text Coatings

    Carbon nanotubes are proposed for reinforcement of the hydroxyapatite coatings to improve their adhesion, resistance to mechanical loads, biocompatibility, bioactivity, corrosion resistance, and antibacterial protection. So far, research has shown that all these properties are highly susceptible to the composition and microstructure of coatings. The present research is aimed at studies of multi-wall carbon nanotubes in three different combinations: multi-wall carbon nanotubes layer, bilayer coating composed of multi-wall carbon nanotubes deposited on nanohydroxyapatite deposit, and hybrid coating comprised of simultaneously deposited nanohydroxyapatite, multi-wall carbon nanotubes, nanosilver, and nanocopper. The electrophoretic deposition method was applied for the fabrication of the coatings. Atomic force microscopy, scanning electron microscopy and X-ray electron diffraction spectroscopy, and measurements of water contact angle were applied to study the chemical and phase composition, roughness, adhesion strength and wettability of the coatings. The results show that the pure multiwall carbon nanotubes layer possesses the best adhesion strength, mechanical properties, and biocompatibility. Such behavior may be attributed to the applied deposition method, resulting in the high hardness of the coating and high adhesion of carbon nanotubes to the substrate. On the other hand, bilayer coating, and hybrid coating demonstrated insufficient properties, which could be the reason for the presence of soft porous hydroxyapatite and some agglomerates of nanometals in prepared coatings.