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Politechniki Gdańskiej

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  • ZASTOSOWANIE STATYSTYKI F ROZKŁADU FISHERA-SNEDECORA DO OCENY ISTOTNOŚCI WPŁYWU ZMIAN STOPNIA KOMPRESJI SILNIKA O ZS NA ŚREDNIĄ WARTOŚĆ MIĘDZYSZCZYTOWĄ TEMPERATURY SPALIN WYLOTOWYCH
    • Patrycja Puzdrowska
    2021 Pełny tekst Journal of Polish CIMEEAC

    W artykule omówiono wpływ zmian stopnia kompresji na parametry pracy silnika o ZS, m.in. na temperaturę spalin wylotowych. Przedstawiono budowę stanowiska laboratoryjnego, na którym przeprowadzono badania eksperymentalne. Scharakteryzowano, w jaki sposób w istniejącym silniku wprowadzano faktyczne zmiany stopnia kompresji. Zaprezentowano program badań eksperymentalnych uwzględniający dostępne stanowisko badawcze i jego możliwości pomiarowe. Dokonano analizy statystycznej i merytorycznej uzyskanych wyników pomiarów. Zaproponowano zastosowanie statystyki F rozkładu Fishera-Snedecora do oceny istotności wpływu zmian stopnia kompresji silnika o ZS na średnią wartość międzyszczytową temperatury spalin wylotowych. Analizowano średnią wartość międzyszczytową temperatury spalin w obrębie jednego cyklu pracy silnika o ZS, wyznaczoną na podstawie przebiegu szybkozmiennej temperatury spalin wylotowych. Omówiono wyniki tych analiz oraz przedstawiono utylitarny cel tego typu badań w diagnostyce parametrycznej silników tłokowych.

  • Zbyszkowi. Zbigniew Kosowski 1961-2020
    • Krzysztof Wróblewski
    • Jan Buczkowski
    2021

    Zbyszkowi… Do 19 stycznia 2022 r. w Małej Galerii PLSP w Nałęczowie można oglądać zbiorową wystawę poświęconą pamięci naszego kolegi Zbyszka Kosowskiego. Wracając do lektury teoretycznych tekstów Zbigniewa Kosowskiego powiedziałbym, że był apostołem chaosu energetycznej entropii. Koncept jego teorii UNIWERTYZMU wpisany w kosmiczną skalę „makro”, zyskiwał miano SYSTEMU – to ważne słowo, które wyraża przestrzenie ludzkiej kreacji. Kolejne pojęcia: „ przestrzeń = wolność = sztuka”, były dla niego równoważne i współzależne, będące częściami jak elementy naczynia połączonego. Z czasem jego teoria „schodząc na ziemię” ewoluowała do bardziej ludzkiego wymiaru, jakim było zaangażowanie społeczno-polityczne. To ustanowienie pola twórczej aktywności od działań w mega skali, której jednym z biegunów mogła być kosmiczna czarna dziura, aż do absurdalnego widoku jego ulubionych kur dziobiących ziarno doczesności. Ten paradoksalny dystans przyprawiający wręcz o zawrót głowy był dla Zbyszka Kosowskiego KONKRETEM- a także jednym z ulubionych słów wyrażającym jego zachwyt życiem. Bez wątpienia PLSP Nałęczów było dla Zbyszka Kosowskiego przestrzenią wymiany energii, życiowa otuliną, miejscem spełnienia o czym sam otwarcie mówił. Miał wśród nauczycieli i uczniów grono przyjaciół, był barwną osobowością tej szkoły. W rocznicę śmierci chcemy wspomnieć go wspólną wystawą – Jego oraz przyjaciół artystów. Łukasz Głowacki Artyści biorący udział w wystawie: ZBIGNIEW KOSOWSKI; Jarosław Bartołowicz; Jan Buczkowski; Jarosław Ćwiek; Łukasz Głowacki; Laura Gutowska; Krzysztof Hejke; Piotr Kmieć; Mariusz Kozik; Waldemar Mazurek; Jolanta Męderowicz; Andrzej Oboz; Małgorzata Oboz; Anna Panek; Marek Rogulski; Rafał Roskowiński; Adam Skóra; Zbigniew Strzyżyński; Urszula Ślusarczyk; Henryk Widelski; Krzysztof Wróbelewski.

  • Zdalne Laboratorium Elektroniki z Programem LTspice
    • Piotr Chrzan
    2021 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Celem artykułu jest przedstawienie programu LTspice w otwartym dostępie, jako skutecznego narzędzia do nauczania elektroniki oraz symulacji układów elektronicznych na potrzeby zdalnego laboratorium. Na wybranych przykładach, realizowanych przez studentów: obwodów rezonansowych, stabilizatorów napięcia, wzmacniaczy operacyjnych w układach całkujących, filtrach, wzmacniaczy mocy wyjaśnione są metody analizy w dziedzinie czasu i częstotliwości, metody weryfikacji poprawnego działania układów, oraz podstawy projektowania. Opisane laboratorium było z powodzeniem uruchomione na platformie dydaktycznej enauczanie Politechniki Gdańskiej.

  • Zdalne rozpoznawanie twarzy w poprawie bezpieczeństwa osobistego interweniującego funkcjonariusza Policji
    • Krzysztof Bisior
    • Waldemar Kamiński
    2021 POLICJA KWARTALNIK KADRY KIEROWNICZEJ POLICJI

    Streszczenie: W 2017 r. ruszył w Polsce pilotażowy program zakładania kamer cyfrowych na mundurach policyjnych. Z perspektywy dnia dzisiejszego wiadomo, że kamery będące indywidualnym wyposażeniem policjanta, rejestrując czas, datę i przebieg interwencji, niejednokrotnie stanowią istotny dowód w sprawach spornych, zwłaszcza w sytuacjach pomawiania policjantów o przekroczenie uprawnień podczas interwencji. W dobie nieustannie powstających nowoczesnych technologii, zwłaszcza teleinformatycznych i prac badawczych — które są realizowane w zakresie systemów zdalnego rozpoznawania twarzy — wykorzystywanie nasobnych kamer policyjnych możne przyczynić się do bezpieczeństwa prawnego i fizycznego policjantów. W niniejszej pracy zaproponowano nową metodę umożliwiającą zdalne rozpoznawanie twarzy. Problem ten analizowano w kontekście zarówno bezpiecznej interwencji funkcjonariusza Policji, jak również ochrony danych osobowych. Zaproponowany, należący do grupy metod matematycznych sposób, wykorzystuje pomiary wykonane pomiędzy charakterystycznymi punktami twarzy. Charakterystyczne punkty twarzy kreują pewną trójwymiarową przestrzeń. W trakcie obliczeń wyznaczane są różnice pomiędzy oryginałem a badanym obrazem twarzy. Zastosowanymi parametrami umożliwiającymi weryfikację tych różnic, są wartości kątów obrotu. Uzyskane różnice są następnie poddane analizie statystycznej, która umożliwiaj określenie z założonym prawdopodobieństwem zgodności obrazu badanej twarzy z oryginałem. Pokazane na przykładzie praktycznym rezultaty obliczeń zachęcają do dalszych, bardziej szczegółowych badań teoretyczno–empirycznych. Wykorzystując możliwości wynikające z systemu zdalnego rozpoznawania twarzy, zaproponowano także koncepcję podwyższającą bezpieczeństwo funkcjonariusza Policji podczas interwencji służbowej. Idea koncepcji polega na zastosowaniu zdalnego systemu rozpoznawania twarzy, opcjonalnie: przed podjęciem interwencji lub po podjęciu interwencji. Zaletą takiego podejścia jest fakt, że w przypadku pozytywnej weryfikacji, tj. uzyskania informacji o osobie poszukiwanej, zaginionej, próbującej ucieczki, a nawet niebezpiecznym przestępcy, funkcjonariusze mają możliwość podjęcia stosownej decyzji i zmiany w dalszym postepowaniu taktyki działania.

  • Zjawisko wyścigu w programowaniu współbieżnym
    • Mariusz Matuszek
    2021

    W rozdziale przedstawiono omówienie podstawowego problemu, z jakim, prędzej czy później, styka się każdy programista piszący oprogramowanie wykorzystujące współbieżność. W praktyce będzie to każdy programista starający się w pełni wykorzystywać moc obliczeniową współczesnych wielordzeniowych procesorów i akceleratorów

  • Zmiany przestrzenne w miastach wywołane pandemią COVID-19 a przestrzenny wymiar rewitalizacji.
    • Barbara Zgórska
    2021

    Pandemia COVID-19 wpływa na każdy aspekt współczesnego świata w skali globalnej i lokalnej. Elementem walki z rozprzestrzenianiem się wirusa było między innymi ograniczenie możliwości przemieszczania się. W miastach spowodowało to skupienie uwagi na przestrzennych aspektach środowiska zurbanizowanego. Celem artykułu jest o analiza doraźnych działań podejmowanych w miastach mających łagodzić skutki pandemii wobec działań strategicznych programowanych w ramach rewitalizacji. Aspekty przestrzenne stanowią jeden z głównych obszarów tematycznych programów rewitalizacji jako kompleksowego działania ku poprawie jakości życia mieszkańców miast w obszarach wymagających wsparcia. Artykuł stanowi analizę wybranych inicjatyw podejmowanych w przestrzeni publicznej miast od marca 2020 do września 2020 w ramach przeciwdziałania rozprzestrzenianiu się wirusa COVID-19 i porównanie ich z celami jakie stawiane są w zakresie działań przestrzennych w programach rewitalizacji. Analiza wykonana jest na podstawie przeglądu publikowanych informacji, komunikatów i artykułów opisujących działania podejmowane w różnych miastach w Polsce i na świecie. Doraźne interwencje przestrzenne podejmowane w miastach służące poprawie jakości życia w czasie pandemii są spójne z działaniami przestrzennymi programowanymi w ramach procesów rewitalizacji obszarów zdegradowanych. Część wniosków wynika z obserwacji i indywidualnych doświadczeń autorki jako praktykującej urbanistki.

  • Znaczenie i dynamika efektuacji w działaniach zespołów projektowych IT
    • Beata Krawczyk-Bryłka
    2021 Pełny tekst Zeszyty Naukowe Uniwersytetu Ekonomicznego w Krakowie

    Cel: Celem opracowania jest sprawdzenie, na ile wdrażanie zasad efektuacji jest korzystne dla efektywności zespołów projektowych pracujących nad innowacyjnymi rozwiązaniami i czy wpływa na ich satysfakcję. Metodyka badań: Badania ilościowe zrealizowano w studenckich zespołach projektowych z branży IT, opracowujących rozwiązania na zlecenie interesariuszy zewnętrznych. Do pomiaru zmiennych wykorzystano autorskie kwestionariusze. Przeanalizowano dynamikę modelu działań zespołów na dwóch etapach realizacji projektu. Wyniki badań: Wyniki pokazały małą zmienność modeli podejmowania decyzji w procesie realizacji projektu. Potwierdzono znaczenie integrowania efektuacyjnych i kauzalnych założeń w różnych obszarach funkcjonowania zespołu. Wnioski: Hybrydowy model podejmowania decyzji jest czynnikiem istotnym dla efektywności zespołu. Wkład w rozwój dyscypliny: Analiza efektywności zespołów projektowych w kontekście zasad efektuacji jest zupełnie nowym podejściem w polskiej literaturze przedmiotu.

  • Znaczenie umów o popieraniu i wzajemnej ochronie inwestycji dla bezpośrednich inwestycji zagranicznych na przykładzie wybranych krajów Bałkanów Zachodnich
    • Katarzyna Kubiszewska
    • Dominiki Horodyski
    2021 Pełny tekst Studia Prawno-Ekonomiczne

    Przedmiot badań: Przedmiotem badania jest zależność bezpośrednich inwestycji zagranicznych (BIZ) i sytuacji makroekonomicznej w gospodarkach w okresie transformacji oraz ocena znacze­nia zawieranych przez te kraje umów o popieraniu i wzajemnej ochronie inwestycji (ang. Bila­teral Investment Treaties – BIT) dla napływu bezpośrednich inwestycji zagranicznych. Badania są prowadzone w czterech krajach na Bałkanach Zachodnich: Bośni i Hercegowinie, Chorwacji, Macedonii Północnej i Serbii w latach 2001–2019. Cel badawczy: Celem artykułu jest ocena zależności bezpośrednich inwestycji zagranicznych (BIZ) i sytuacji makroekonomicznej w gospodarkach w okresie transformacji oraz ocena zna­czenia zawieranych przez te kraje umów o popieraniu i wzajemnej ochronie inwestycji (ang. Bilateral Investment Treaties – BIT) dla napływu bezpośrednich inwestycji zagranicznych. Bada­nia wypełniają lukę w wiedzy na temat zarówno znaczenia BIT dla BIZ, jak i znaczenia BIZ dla sytuacji makroekonomicznej.1 Metoda badawcza: Dla oceny znaczenia bezpośrednich inwestycji zagranicznych dla gospodar­ki oszacowano korelację między BIZ a wskaźnikami opisującymi sytuację makroekonomiczną, w tym wzrost PKB, PKB per capita oraz stabilność makroekonomiczną. W dalszej części skon­centrowano się na BIT jako potencjalnych narzędziach oddziałujących na skłonność inwestorów zagranicznych do podjęcia decyzji o zainwestowaniu w kraju rozwijającym się, zapewniającym ochronę inwestycji zagranicznych na podstawie BIT. W związku z tym sprawdzono, czy po za­warciu umowy BIT nastąpił wzmożony napływ BIZ. Dane pozyskano ze źródeł Banku Świato­wego, baz danych UNCTAD i EBOR, a także baz instytucji lokalnych w każdym badanym kraju. Wyniki: Wnioski z badań sugerują, że z jednej strony napływ BIZ nie był istotnym czynnikiem rozwoju gospodarczego w badanym regionie, a z drugiej strony – BIT nie stanowiły istotnego narzędzia oddziałującego na decyzje inwestycyjne zagranicznych inwestorów.

  • β-cyclodextrin-containing polymer based on renewable cellulose resources for effective removal of ionic and non-ionic toxic organic pollutants from water
    • Koleta Hemine
    • Natalia Łukasik
    • Maria Gazda
    • Izabela Nowak
    2021 Pełny tekst JOURNAL OF HAZARDOUS MATERIALS

    A novel, bio-derived cyclodextrin-based trifunctional adsorbent has been successfully synthesized for efficient, rapid and simultaneous removal of a broad-spectrum of toxic ionic (anionic and cationic dyes) and non-ionic organic pollutants from water. The composition, morphology and the presence of functional groups in the obtained sorption material were characterized by elemental analysis, XRD, SEM, and FTIR spectroscopy. The adsorption results were represented by cationic dye (crystal violet, CV) and endocrine disrupting compound (bisphenol A, BPA) as an adsorbate. The sorption processes of the model pollutants were studied with both kinetic and equilibrium models. The results showed that the sorption was rapid (less than 1 min) and the time evolution could be fitted using a pseudo-second order model. According to Langmuir isotherm model, the maximum adsorption capacities were found at 113.64 and 43.10 mg g-1 for BPA and CV, respectively. The adsorption ability of β-CDPs was kept nearly on the same level after five regeneration cycles. Furthermore, almost complete removal of the pollutants was observed during the treatment of real effluents samples thus the bio-derived, cheap and reusable BAN-EPI-CDP has a promising potential for practical applications.

  • Аналіз положень статутів польських та українських ЗВО: дослідження особливостей статутів закладів вищої освіти у контексті університетської автономії та чинного законодавства у сфері вищої освіти в Польщі та Україні
    • Krzysztof Leja
    • Viacheslav Komarov
    • Iryna Degtyarova
    2021

    дослідження, реалізоване власними силами аналітично-експертною організацією Фундація польських ректорів – Інститут суспільства знань у 2016–2018 рр., було присвячено аналізу сфери врядування/governance у вищій освіті в Україні та Польщі. Метою дослідження було дослідити думку ректорів закладів вищої освіти Спілки та KRASP щодо деяких аспектів функціонування сфери врядування у вищій освіті в обох країнах. Анкетне дослідження охоплювало 10 основних тематичних блоків: • Академічні цінності (внутрішні) сучасного університету; • Місія, призначення та завдання закладу вищої освіти; • Спосіб управління у системі вищої освіти; • Принципи університетської автономії на тлі завдань держави та засад зовнішнього нагляду; • Система джерел права у сфері вищої освіти і принципи його становлення; • Структура закладу вищої освіти; • Органи управління закладом вищої освіти; • Політика розвитку закладу вищої освіти; • Застосування категорій якості в управлінні закладом вищої освіти; • Фінансування системи вищої освіти;

  • 1D convolutional context-aware architectures for acoustic sensing and recognition of passing vehicle type
    • Adam Kurowski
    • Szymon Zaporowski
    • Andrzej Czyżewski
    2020

    A network architecture that may be employed to sensing and recognition of a type of vehicle on the basis of audio recordings made in the proximity of a road is proposed in the paper. The analyzed road traffic consists of both passenger cars and heavier vehicles. Excerpts from recordings that do not contain vehicles passing sounds are also taken into account and marked as ones containing silence. The neural network architecture employed for these tasks is a 1D convolutional network. Two types of classifiers are tested: one analyzing only the current audio frame and one analyzing three consecutive audio frames that allow us to take into account the context of the middle frame occurrence. The neural network is trained on datasets derived for four frame lengths, namely 50 ms, 100 ms, 200 ms, and 400 ms. Results of statistical analysis of both network classification accuracy are presented. The context-aware variant of a neural network performed better in a statistically significant manner for three out of four investigated frame lengths

  • 3D mesoporous α-Co(OH)2 nanosheets electrodeposited on nickel foam: A new generation of macroscopic cobalt-based hybrid for peroxymonosulfate activation
    • Ruixia Yuan
    • Minglang Jiang
    • Simeng Gao
    • Zhaohui Wang
    • Huaiyuan Wang
    • Grzegorz Boczkaj
    • Zhanjian Liu
    • Jun Ma
    • Zhijun Li
    2020 CHEMICAL ENGINEERING JOURNAL

    Cobalt-based catalysts with high stability and facile recovery for heterogeneous peroxymonosulfate (PMS) activation are still rather sparse and therefore highly desirable. Herein, 3D mesoporous α-Co(OH)2 nanosheets was created on robust nickel foam (NF) via facile electrodeposition approach at 6 mA/cm2 for only 400 s. Almost complete removal of phenol can be achieved within 7 min with a degradation rate of 0.39 min−1, 2 times higher than that with ever-prevalent Co3O4 derived from direct calcination of α-Co(OH)2/NF. This can be attributed to the hydrotalcite-like hexagonal structure of α-Co(OH)2 with large interlayer spacing for enhancing the catalytic performance. The low activation energy of Co(OH)2/NF (53.8 kJ/mol) indicates its lower reaction energy barrier for PMS activation. Moreover, the influences of electrodeposition parameters (i.e. current density, deposition time), PMS dosage, initial pH and coexisting anions (HCO3−, SO42−, Cl−) on the phenol degradation were systematically evaluated. The recycling tests revealed the prominent stability of Co(OH)2/NF. The quenching tests verified that SO4− radicals acted as the predominant reactive species for phenol decomposition. The possible reaction mechanisms were proposed based on the intermediates identification. The findings of this work suggest the great potentials of the 3D macroscopic Co(OH)2/NF in water purification, and open up new avenues for scalable preparing recyclable heterogeneous catalysts.

  • 3D PCB package for GaN inverter leg with low EMC feature
    • Paweł Derkacz
    • Piotr Chrzan
    • Pierre-Olivier Jeannin
    • Piotr Musznicki
    • Mickael Petit
    • Jean-Luc Schanen
    2020 Pełny tekst

    This paper presents the adaptation of a 3D integration concept previously used with vertical devices to lateral GaN devices. This 3D integration allows to reduce loop inductance, to ensure more symmetrical design with especially limited Common Mode emission, thanks to a low middle point stray capacitance. This reduction has been achieved by both working on the power layout and including a specific shield between the devices and the heatsink. The performances of this 3D layout have been verified in comparison with a more conventional 2D implementation, using both simulations and measurements.

  • 3D POINT-CLOUD SPATIAL EXPANSION BY TOTAL LEAST-SQUARES LINE FITTING
    • Paweł S. Dąbrowski
    • Marek Zienkiewicz
    2020 PHOTOGRAMMETRIC RECORD

    Point-cloud spatial expansion (PCSE) allows the creation of a new pointcloud form that presents an alternative geometry of an entire object in a single spatial view. Spatial expansion facilitates the analysis process and introduces an additional spatial parameter describing the point cloud. An important element of the PCSE method is determining the position of the axis of symmetry of a symmetrical object: the procedure for determining the parameters of this axis (set of cross-sectional centres) of the object’s point cloud by the total least-squares method is presented. The estimation results were used to create a spatial expansion of the point cloud of a cylindrical object, demonstrating the usefulness of total least-squares fitting to the PCSE method.

  • 3D Vision System for a Robotic Arm Based on Equal Baseline Camera Array
    • Adam Kaczmarek
    2020 Pełny tekst JOURNAL OF INTELLIGENT & ROBOTIC SYSTEMS

    This paper presents a lightweight 3D vision system called Equal Baseline Camera Array (EBCA). EBCA can work in different light conditions and it can be applied for measuring large range of distances. The system is a useful alternative to other known distance measuring devices such as structured-light 3D scanners, time-of-flight cameras, Light Detection and Ranging (LIDAR) devices and structure from motion techniques. EBCA can be mounted on a robotic arm without putting significant load on its construction. EBCA consists of a central camera and a ring of side cameras. The system uses stereo matching algorithms to acquire disparity maps and depth maps similarly as in case of using stereo cameras. This paper introduces methods of adapting stereo matching algorithms designed for stereo cameras to EBCA. The paper also presents the analysis of local, semi-global and global stereo matching algorithms in the context of the EBCA usage. Experiments show that, on average, results obtained from EBCA contain 37.49% less errors than the results acquired from a single stereo camera used in the same conditions.

  • 45 lat minęło - kolejne spotkanie technologów na Wydziale Mechanicznym
    • Adam Barylski
    2020 Pismo PG

    Omówiono przebieg Jubileuszowego Zjazdu Absolwentów Wydziału Mechanicznego Politechniki Gdańskiej, którzy ukończyli studia wiosną i jesienią w roku 1974.

  • 60 GHz Microstrip Van Atta Arrays for Millimeter Wave Identification and Localization
    • Kamil Trzebiatowski
    • Mateusz Rzymowski
    • Łukasz Kulas
    • Krzysztof Nyka
    2020 Pełny tekst

    In this paper performance comparison of co-polarized and cross-polarized microstrip Van Atta arrays working in the 60 GHz frequency range is presented. They can be treated as simple chipless RFID tags with frequency response based identification. Tags with three different nominal resonance frequencies of 57, 62 and 67 GHz are designed by scaling optimized base model. Designed 62 GHz co-polarized and cross-polarized arrays with four interconnected pairs of elementary antenna arrays have small dimensions of 20 x 18 mm and 36 x 23 mm, and exhibit RCS levels of –20 and -22 dBsm, respectively. The influence of number of interconnected antennas on the radar cross-section (RCS) of the tag is investigated. Frequency responses of the tags are also examined and compared for both types of tags with 0.80 GHz (co-polarized) and 2.10 GHz (cross-polarized) 3 dB bandwidth of the RCS response at 60 degree interrogation angle.

  • 70 LAT PRAKTYKI POMIAROWEJ W OCENIE WŁAŚCIWOŚCI UZIEMIEŃ METODĄ UDAROWĄ
    • Stanisław Wojtas
    • Marek Wołoszyk
    • Marek Olesz
    2020 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Przedstawiono liczącą ok. 70 lat historię prac związanych z rozwojem sposobów oceny uziemień wykorzystujących metodę udarową. Pierwsze prace związane z tym zagadnieniem zostały rozpoczęte w połowie ubiegłego wieku na Politechnice Gdańskiej z inicjatywy profesora Stanisława Szpora. Omówiono metodę pomiaru, stosowane kolejne generacje mierników, możliwości oceny uziemień i różne definicje normalizacyjne opisujące właściwości uziemienia mierzone przy prądach udarowych o czasie czoła zbliżonym do czasu rzeczywistego wyładowania piorunowego.

  • A 1-nS 1-V Sub-1-µW Linear CMOS OTA with Rail-to-Rail Input for Hz-Band Sensory Interfaces
    • Jacek Jakusz
    • Waldemar Jendernalik
    • Grzegorz Blakiewicz
    • Miron Kłosowski
    • Stanisław Szczepański
    2020 Pełny tekst SENSORS

    The paper presents an operational transconductance amplifier (OTA) with low transconductance (0.62–6.28 nS) and low power consumption (28–270 nW) for the low-frequency analog front-ends in biomedical sensor interfaces. The proposed OTA implements an innovative, highly linear voltage-to-current converter based on the channel-length-modulation effect, which can be rail-to-rail driven. At 1-V supply and 1-Vpp asymmetrical input driving, the linearity error in the current-voltage characteristics is 1.5%, while the total harmonic distortion (THD) of the output current is 0.8%. For a symmetrical 2-Vpp input drive, the linearity error is 0.3%, whereas THD reaches 0.2%. The linearity is robust for the mismatch and the process-voltage-and-temperature (PVT) variations. The temperature drift of transconductance is 10 pS/°C. The prototype circuit was fabricated in 180-nanometer CMOS technology.

  • A Comparison of Empirical Correlations of Viscosity and Thermal Conductivity of Water-Ethylene Glycol-Al2O3 Nanofluids
    • Dorota Sawicka
    • Janusz Cieśliński
    • Sławomir Smoleń
    2020 Pełny tekst Nanomaterials

    Because of their superb thermal conductivity, nanofluids are seen as new generation of cooling mediums in many engineering applications. It is well established that even a small amount of nanoparticles mixed with a base fluid may result in distinct thermal conductivity enhancement. On the other hand, addition of nanoparticles to the base fluid results in its substantial viscosity increase. Therefore, it is very dicult to evaluate the relative importance of viscosity and thermal conductivity of the nanofluid on convective heat transfer performance. In order to estimate such resultant impact properly, it is necessary to develop reliable correlation equations for predictions of these two thermophysical properties of nanofluids. In this paper, the thermal conductivity and dynamic viscosity of five fluids, i.e., pure water, ethylene glycol (EG) and three mixtures of water and EG with volume ratio of 40:60, 50:50 and 60:40 have been experimentally determined. The aforementioned fluids served as base fluids in nanofluids with Al2O3 nanoparticles at the concentration of 0.01%, 0.1% and 1% by weight. A set of 20 correlations for prediction of thermal conductivity and dynamic viscosity of base fluids and corresponding nanofluids has been developed. Moreover, present results have been confronted with literature data and predictions made by use of carefully selected recognized literature correlations.

  • A comprehensive assessment of environmental pollution by means of heavy metal analysis for oysters' reefs at Hab River Delta, Balochistan, Pakistan
    • Sadar Aslam
    • Malik Wajid Hussain Chan
    • Ghazala Siddiqui
    • Grzegorz Boczkaj
    • Syed Jamil Hasan Kazmi
    • Mohib Reza Kazmi
    2020 MARINE POLLUTION BULLETIN

    The heavy metal pollution status of oyster reefs has been assessed with respect to ten metals pollutants in seawater, sediments, and tissues of above two oysters (soft tissues and shells) for assessing the pollution status in a short food chain in Hab River Delta. The results showed that heavy metals accumulated in M. bilineata were higher than those in M. cuttackensis. Simultaneously, the population of M. bilineata species has been ironically decreasing as a results of high pollution. The determined concentrations revealed a significant differences in their profiles among sediments, seawater and bioaccumulation in tissues and shells of two native oysters. The present study also compared these metal concentrations with national and international database by applying different pollution indices. Heavy metals in all samples were above the national environmental quality standards (NEQS-Pakistan). High level of pollution with an alarming condition of Hab River Delta need more attention for coastal management.

  • A comprehensive evaluation of flexible FDM/FFF 3D printing filament as a potential material in medical application
    • Agnieszka Haryńska
    • Iga Carayon
    • Paulina Kosmela
    • Kamil Szeliski
    • Marcin Łapiński
    • Marta Pokrywczyńska
    • Justyna Kucińska-Lipka
    • Helena Janik
    2020 Pełny tekst EUROPEAN POLYMER JOURNAL

    The use of FDM/FFF in 3D printing for medical sciences is becoming common. This is due to the high availability and decent price of both 3D printers and filaments useful for FDM/FFF. Currently, researchers' attention is focused mainly on the study of medical filaments based on PLA, PCL or their modifications. This contributes to insufficient diversity of medical-grade filaments on the market. Moreover, due to the lack of specified standards for filaments testing, manufacturers often provide merely the characteristics of the raw materials, which were used for filaments fabrication. This lack of comprehensive data can be problematic when viewed as medical-grade material. As a consequence of this overview, we have performed a comprehensive evaluation of a flexible medical-grade filament for FDM/FFF 3DP - Bioflex® (Filoalfa). We have performed complex characterization through a variety of methods and techniques including spectroscopic analysis (FTIR, Raman), dynamic mechanical analysis (DMA), thermal properties (DSC, TGA), rheological characteristic (MFR). In the next step, printed Bioflex® samples were utilized to characterize the material behaviour after the 3D printing process. The mechanical analysis allowed to estimate how the material strength decreases after the printing process according to the values given in the technical data sheet. The contact angle measurements determined wettability of the Bioflex® printouts. Performed series of in vitro studies were carried out to assess its potential as implantable structures. In conclusion, 3D printing process did not affect the printouts biocompatibility (ISO 10993:5). Accelerated degradation studies indicated elevated hydrolysis resistance of printed samples. In turn, performed incubation in simulated body fluid (SBF) solution, revealed carbonated hydroxyapatite (HAp) deposition on printouts surface indicating their bioactive properties. Thus, studied filament seems to be a suitable candidate for further development of FDM/FFF 3DP structures for advanced biological and medical application.

  • A concept of zero-dimensional and three-dimensional thermodynamic modelling of steam storage in a steam cycle
    • Paweł Ziółkowski
    2020

    This work presents the thermodynamic model of steam storage in a steam cycle. The innovative steam storage is an integral part of the unit and thus responds quickly to changes in load. This enhances the primary control reserve while maintaining high efficiency of energy conversion. With regard to power plants, it improves the operational safety of generation units, as it prevents boiler and turbines overload in the case of steep reduction in the load. A steam power plant able to swiftly adjust its generation to load changes becomes more competitive on the capacity market due to improve its dynamic characteristics. The relative disadvantage of the steam storage is its limited capacity. Therefore, the article includes a comprehensive assessment of the power plant parameters that will allow developing guidelines and recommendations to determine the optimal operation modes of the steam accumulator for the case of the underlying reference process. This will also take into account changing ambient conditions and current operational requirements. Therefore, it is necessary to use zero-dimensional modelling (0D) which relates to the design level strictly focused on thermodynamic parameters at specific points in the thermodynamic cycle. However, the three-dimensional approach, which allows determining temperature fields, displacements and stresses in relevant space is used for more accurate analysis. This paper also presents the relationship between the different approaches in relation to steam storage. The steam accumulator itself will be analysed in detail by means of Thermal-FSI (Fluid Solid Interaction) based on flow models with phase transitions induced both by change of pressure and temperature. Computational Solid Dynamics (CSD) models will be included to obtain the thermal and mechanical stresses. The mathematical modelling of complex physical phenomena in the steam storage is of increasing interest, particularly with regard to energy storage in the steam cycle. However, taking into account zero-dimensional modelling it is possible to show that charging the energy storage leads to a load reduction of up to 6.5%. On the other hand, discharging the energy storage can produce an additional net power of up to 4.1%. However, a new three-dimensional FSI analyses are necessary.

  • A Conformal Circularly Polarized Series-Fed Microstrip Antenna Array Design
    • Stanislav Ogurtsov
    • Sławomir Kozieł
    2020 Pełny tekst IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    A conformal circularly polarized series-fed microstrip array design for broadside radiation is presented. The array aperture under design is conformal to a cylindrical surface of a given radius. The approach we present primarily addresses focusing of the circularly polarized major lobe of the conformal array by proper dimensioning of the aperture spacings. The proposed analytical models yield the values of the element spacings within the series-fed conformal array aperture, and elementspecific spacings of the patch radiators within each circularly polarized element. These spacings are critical to produce a broadside circularly polarized major lobe at the design frequency. Subsequently, each array element is equipped with an in-line matching quarter wave transformer. Measured characteristics of the X-band conformal array validate the proposed design approach.

  • A continual model of a damaged medium used for analyzing fatigue life of polycrystalline structural alloys under thermal–mechanical loading
    • Ivan Volkov
    • Leonid Igumnov
    • Francesco dell'Isola
    • Svetlana Litvinchuk
    • Victor Eremeev
    2020 Pełny tekst CONTINUUM MECHANICS AND THERMODYNAMICS

    The main physical laws of thermal–plastic deformation and fatigue damage accumulation processes in polycrystalline structural alloys under various regimes of cyclic thermal–mechanical loading are considered. Within the framework of mechanics of damaged media, a mathematical model is developed that describes thermal–plastic deformation and fatigue damage accumulation processes under low-cycle loading. The model consists of three interrelated parts: relations defining plastic behavior of the material, accounting for its dependence on the failure process; evolutionary equations describing damage accumulation kinetics; a strength criterion of the damaged material. The plasticity model based on the notion of yield surface and the principle of orthogonality of the plastic strain vector to the yield surface is used as defining relations. This version of defining equations of plasticity describes the main effects of the deformation process under monotone cyclic, proportional and nonproportional loading regimes. The version of kinetic equations of damage accumulation is based on introducing a scalar parameter of damage degree and energy principles, and account for the main effects of nucleation, growth and merging of microdefects under arbitrary regimes of low-cycle loading. The strength criterion of the damaged material is based on reaching a critical value of the damage degree. The results of numerically modeling cyclic thermal–plastic deformation and fatigue damage accumulation in heat-resistant alloys (Nimonic 80A, Haynes 188) under combined thermal–mechanical loading are presented. Special attention is paid to the issues of modeling the processes of cyclic thermal–plastic deformation and fatigue damage accumulation for complex deformation processes accompanied by the rotation of the main stress and strain tensor areas. It is shown that the present damaged medium model accurately enough for engineering purposes describes the processes of cyclic isothermal and nonisothermal deformation and fatigue damage accumulation under combined thermal–mechanical loading and makes it possible to evaluate low-cycle fatigue life of heat-resistant alloys under arbitrary deformation trajectories.

  • A Critical Reanalysis of Uncontrollable Washboarding Phenomenon in Metal Band Sawing
    • Kazimierz Orłowski
    • Michał Dobrzyński
    • Grzegorz Gajowiec
    • Marcin Lackowski
    • Tomasz Ochrymiuk
    2020 Pełny tekst Materials

    The article analyzes the cutting process of hard bars. Investigations conducted in industrial conditions demonstrated the presence of surface errors in the machined workpieces in the form of washboard patterns. The purpose of this study was to analyze the results of cutting on band sawing machines with different band saw blades. The cutting processes were conducted on three different horizontal band sawing machine types. Analyzed material was an alloy steel Ø40 mm rod with a hardened surface covered with a thin layer of chromium. The hardness of the outer layer was 547 HV with a core hardness of 180 HV. The surface topography measurements of the processed workpieces were carried out with the 3D Optical Profiler, which supplied information on the irregularities of the processed material texture. In each of the analyzed cases, a corrugated surface was obtained after sawing, which is the effect of the occurrence of the washboarding phenomenon, despite the fact that the teeth of each band saw had variable pitches. The washboarding phenomenon when cutting rods with hard surfaces is caused by the phenomenon of wave regeneration. Despite the use of variable pitch saw blades, the cutting process results in rippling of the sawn surface, which is caused by the high hardness of the outer layer of the workpiece, as well as by the type of tool with spring setting of teeth.

  • A Development of a Capacitive Voltage Divider for High Voltage Measurement as Part of a Combined Current and Voltage Sensor
    • Roman Hrbac
    • Vaclav Kolar
    • Mikołaj Bartłomiejczyk
    • Tomas Mlcak
    • Petr Orsag
    • Jakub Vanc
    2020 Pełny tekst Elektronika Ir Elektrotechnika

    This article deals with the development of capacitive voltage divider for high voltage measurements and presents a method of analysis and optimization of its parameters. This divider is a part of a combined voltage and current sensor for measurements in high voltage power networks. The sensor allows continuous monitoring of the network distribution status and performs a quick diagnosis and location of possible network failures. Deployment of these devices will support semi-autonomous control of power networks and it can be considered as a step from traditional power grids toward smart grids. This is a worldwide trend connected with increasing number of renewable energy sources and plug-in electric vehicles as described in. In this way, it contributes to the reliability of the distribution network. Together with automated control techniques and fault location methods, it enables its self-healing capability. The following characteristics required for the sensor include: current measurement error up to 2 %, voltage measurement error up to 0.5 %, and power measurement error up to 5 %. At the same time, it is necessary that the sensor is cost-effective - relatively cheap. There were selected capacitors made in series production for the capacitive divider designing. The capacitive voltage divider was tested in terms of time and temperature stability; the results are described in the paper. Then, the method of mathematical correction of a temperature dependence of the capacitive voltage divider was suggested and tested.

  • A Finer Point on Vision
    • Karolina Zielińska-Dąbkowska
    2020 Lighting Design and Application

    As an IES Member, I look forward to each issue of LD+A and read them with great interest as they are often very informative. To my surprise, the Research article (May 2019, p. 76) has an error which should be corrected.

  • A five-year retrospective study shows increasing rates of antimicrobial drug resistance in Cabo Verde for both Staphylococcus aureus and Escherichia coli
    • Tamar Monteiro
    • Magdalena Wysocka
    • Elena Tellez
    • Ofelia Monteiro
    • Luzia Spencer
    • Elisa Veiga
    • Sandra Monteiro
    • Carine De Pina
    • Deisy Goncalves
    • Sandrine De Pina
    • Ludgero Correia
    • Joao Moreno
    • Teresa Conceicao
    • Marta Aires De Sousa
    • Herminia De Lencastre
    • Laura J Gray
    • Manish Pareek
    • David R Jenkins
    • Sandra Beleza
    • Marco R Oggioni
    • Isabel Ines Araujo
    2020 Pełny tekst Journal of Global Antimicrobial Resistance

    Objectives Data on baseline drug resistance is important in informing future antimicrobial stewardship programs. So far, no data on the antimicrobial drug resistance of clinical isolates was available for the African archipelago of Cabo Verde. Methods We have performed a retrospective analysis over five-years (2013-17) of the antimicrombial drug susceptibility profiles of clinical isolates in the two main hospitals of Cabo Verde. For Escherichia coli and Staphylococcus aureus, representing respectively 47% and 26% of all clinical isolates, the antimicrobial drug resistance profile was reported for six representative drugs. Results For E. coli we detected an increase in resistance to ampicillin, amoxicillin/clavulanic acid, ceftriaxone, ciprofloxacin, and trimethoprim-sulfamethoxazole and for S. aureus to methicillin, erythromycin and trimethoprim-sulfamethoxazole. This increase in both the most commonly isolated bacterial pathogens is of alarm as it might compromise empirical treatment in a setting with limited access to laboratory testing. Conclusions When compared to the published low resistance rates in carriage isolates, the more alarming situation in clinical isolates for S. aureus might encourage antimicrobial stewardship programs to reduce MRSA in the hospital settings, possibly as part of the Cabo Verdean national plan against antimicrobial drug resistance.

  • A Flexible Nafion Coated Enzyme‐free Glucose Sensor Based on Au‐dimpled Ti Structures
    • Adrian Olejnik
    • Katarzyna Siuzdak
    • Jakub Karczewski
    • Katarzyna Grochowska
    2020 ELECTROANALYSIS

    The detection of glucose at low concentrations using electrochemical sensors is of great importance due to the possibility of using different human body fluids than blood, such as e.g. urine, saliva, sweat or tears. The interest behind those biofluids is related to their utility in non-invasive sugar determination. In this work, we present flexible, fully biocompatible electrode material based on Au nanoparticles immobilized onto titanium dimples. Au Ti heterostructures were obtained via electrochemical anodization of titanium foil in presence of fluoride anions followed by chemical etching, magnetron sputtering of gold and subsequent thermal dewetting in continuous regime. In the last step of fabrication, electrodes were modified by permselective Nafion membrane. The selection of the best electrode material among different configurations was carried out basing on the electrochemical activity in the contact with 5 mM glucose dissolved in neutral air-saturated 0.1 M PBS. For the 10 nm Au dewetted gold film, limit of detection of 30 μM and high sensitivity of 93 mAcm 2mM 1 were achieved. Application of Nafion membrane caused complete inhibition of the impact of various interference species onto the glucose detection. Good selectivity and repeatability combined with the resistance to prolonged mechanical stress suggest that prepared material can be used in noninvasive glucose sensig

  • A framework for accelerated optimization of antennas using design database and initial parameter set estimation
    • Sławomir Kozieł
    • Adrian Bekasiewicz
    2020 Pełny tekst ENGINEERING COMPUTATIONS

    The purpose of this paper is to exploit a database of pre-existing designs to accelerate parametric optimization of antenna structures is investigated. Design/methodology/approach The usefulness of pre-existing designs for rapid design of antennas is investigated. The proposed approach exploits the database existing antenna base designs to determine a good starting point for structure optimization and its response sensitivities. The considered method is suitable for handling computationally expensive models, which are evaluated using full-wave electromagnetic (EM) simulations. Numerical case studies are provided demonstrating the feasibility of the framework for the design of real-world structures. Findings The use of pre-existing designs enables rapid identification of a good starting point for antenna optimization and speeds-up estimation of the structure response sensitivities. The base designs can be arranged into subsets (simplexes) in the objective space and used to represent the target vector, i.e. the starting point for structure design. The base closest base point w.r.t. the initial design can be used to initialize Jacobian for local optimization. Moreover, local optimization costs can be reduced through the use of Broyden formula for Jacobian updates in consecutive iterations. Research limitations/implications The study investigates the possibility of reusing pre-existing designs for the acceleration of antenna optimization. The proposed technique enables the identification of a good starting point and reduces the number of expensive EM simulations required to obtain the final design. Originality/value The proposed design framework proved to be useful for the identification of good initial design and rapid optimization of modern antennas. Identification of the starting point for the design of such structures is extremely challenging when using conventional methods involving parametric studies or repetitive local optimizations. The presented methodology proved to be a useful design and geometry scaling tool when previously obtained designs are available for the same antenna structure.

  • A framework for Air Quality Management Zones - Useful GIS-based tool for urban planning: Case studies in Antwerp and Gdańsk
    • Joanna Badach
    • Dimitri Voordeckers
    • Lucyna Nyka
    • Maarten Van Acker
    2020 Pełny tekst BUILDING AND ENVIRONMENT

    There is a growing recognition of the importance of proper urban design in the improvement of air flow and pollution dispersion and in reducing human exposure to air pollution. However, a limited number of studies have been published so far focusing on the development of standard procedures which could be applied by urban planners to effectively evaluate urban conditions with respect to air quality. To fill this gap, a new approach for the determination of urban Air Quality Management Zones (AQMZs) was proposed and presented based on two case studies: Antwerp, Belgium and Gdańsk, Poland. The main objectives of the study were to 1) formulate a theoretical framework for the management of urban ventilation potential and human exposure to air pollution and to 2) develop methods for its implementation by means of a geographic information system (GIS). As a result of the analysis, the typologies that may be associated with decreased ventilation potential and the areas that require close monitoring due to potential human exposure to air pollution were identified for both cities. It is advocated that delimiting these typologies – combined with investigating local climate, wind and topography conditions and air pollution characteristics – could constitute a preliminary step in the urban planning process aimed at air quality improvement. These methods can be further applied to other urban areas in order to indicate where detailed studies are required and to facilitate the development of planning guidelines. Moreover, the directions for further research and urban planning strategies were discussed.

  • A Framework for Enhancing Supplier Selection Process by Using SOEKS and Decisional DNA
    • Muhammad Ahmed
    • Cesar Sanin
    • Edward Szczerbicki
    2020 Pełny tekst Communications in Computer and Information Science

    Abstract. Supplier selection process is one of the significant stages in supply chain management for industrial manufactured products. It plays an integral role in the success of any manufacturing organization and is an important part starting right from selecting raw material to dispatch of finished products. This paper contributes to enhance the supplier selection process by proposing a multi-criteria decision making framework for industrial manufactured products. The proposed framework is based on smart knowledge management technique called Set of experience knowledge structure (SOEKS) and Decisional DNA, which makes the proposed approach dynamic in nature as it updates itself every time a decision is taken.

  • A global multinational survey of cefotaxime-resistant coliforms in urban wastewater treatment plants
    • Roberto Marano
    • Telma Fernandes
    • Celia M. Manaia
    • Olga Nunes
    • Donald Morrison
    • Thomas U. Berendonk
    • Norbert Kreuzinger
    • Tanel Telson
    • Gianluca Corno
    • Despo Fatta-Kassinos
    • Christophe Merlin
    • Edward Topp
    • Edouard Jurkevitch
    • Leonie Henn
    • Andrew Scott
    • Stefanie Hess
    • Katarzyna Slipko
    • Mailis Laht
    • Veljo Kisand
    • Andrea Di Cesare
    • Popi Karaolia
    • Stella G. Michael
    • Alice L Petre
    • Roberto Rosal
    • Amy Pruden
    • Virgina Riquemle
    • Ana Aguera
    • Belen Esterban
    • Aneta Łuczkiewicz
    • Agnieszka Kalinowska
    • Anne Leonard
    • William H. Gaze
    • Anthony A. Adegooke
    • Thor A. Stenstrom
    • Alfieri Pollice
    • Carlo Salerno
    • Carsten U. Schwermer
    • Paweł Krzemiński
    • Helene Guilloteau
    • Erica Donner
    • Barbara Drigo
    • Giovanni Libralato
    • Marco Guida
    • Helmut Burgmann
    • Karin Beck
    • Hemda Garelick
    • Marta Tacao
    • Isabel Henriques
    • Isabel Martinez-Alcala
    • Jose M. Guillien-Navarro
    • Magdalena Popowska
    • Marta Piotrowska
    • Markos Quintela-Baluja
    • Joshua T. Bunce
    • Maria I. Polo-Lopez
    • Samira Nahim-Granados
    • Marie-Noelle Pons
    • Milena Milakovic
    • Nikolina Udikovic-Kolic
    • Jerome Ory
    • Traore Ousmane
    • Pilar Caballero
    • Antoni Oliver
    • Sara Rodriguez-Mozaz
    • Jose L. Balcazar
    • Thomas Jager
    • Thomas Schwartz
    • Ying Yang
    • Shichun Zou
    • Yunho Lee
    • Younggun Yoon
    • Bastian Herzog
    • Heidrun Mayrhofer
    • Om Prakash
    • Yogesh Nimonkar
    • Ester Heath
    • Anna Baraniak
    • Joana Abreu-Silva
    • Manika Choudhury
    • Leonardo P. Munoz
    • Stela Krizanovic
    • Gianluca Brunetti
    • Ayella Maile-Moskowitz
    • Connor Brown
    • Eddie Cytryn
    2020 Pełny tekst ENVIRONMENT INTERNATIONAL

    The World Health Organization Global Action Plan recommends integrated surveillance programs as crucial strategies for monitoring antibiotic resistance. Although several national surveillance programs are in place for clinical and veterinary settings, no such schemes exist for monitoring antibiotic-resistant bacteria in the environment. In this transnational study, we developed, validated, and tested a low-cost surveillance and easy to implement approach to evaluate antibiotic resistance in wastewater treatment plants (WWTPs) by targeting cefotaxime-resistant (CTX-R) coliforms as indicators. The rationale for this approach was: i) coliform quantification methods are internationally accepted as indicators of fecal contamination in recreational waters and are therefore routinely applied in analytical labs; ii) CTX-R coliforms are clinically relevant, associated with extended-spectrum β-lactamases (ESBLs), and are rare in pristine environments. We analyzed 57 WWTPs in 22 countries across Europe, Asia, Africa, Australia, and North America. CTX-R coliforms were ubiquitous in raw sewage and their relative abundance varied significantly (<0.1% to 38.3%), being positively correlated (p < 0.001) with regional atmospheric temperatures. Although most WWTPs removed large proportions of CTX-R coliforms, loads over 103 colony-forming units per mL were occasionally observed in final effluents. We demonstrate that CTX-R coliform monitoring is a feasible and affordable approach to assess wastewater antibiotic resistance status.

  • A Highly Sensitive Planar Microwave Sensor for Detecting Direction and Angle of Rotation
    • Abhishek Jha
    • Adam Lamęcki
    • Michał Mrozowski
    • Bozzi Maurizio
    2020 Pełny tekst IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES

    This article presents a technique based on a modified complementary split-ring resonator (CSRR) to detect angular displacement and direction of rotation with high resolution and sensitivity over a wide dynamic range. The proposed microwave planar sensor takes advantage of the asymmetry of the sensor geometry and measures the angle of rotation in terms of the change in the relative phase of the reflection coefficients. The sensor consists of a movable modified CSRR (the rotor) and a microstrip line with a circular defect in the ground plane (the stator). By selecting the substrate material and the rotor thickness, the sensor can be designed to work at different operating frequencies. A theoretical model of the sensor is proposed and is followed by a detailed numerical analysis involving equivalent circuit simulations, full-wave computations, and measurement results. Using positioning error estimation and air-gap analysis, a technique based on phase-change measurements is found to be better than those based on magnitude measurements alone. The maximum sensitivity for measuring the angular rotation is found to be a 4.3◦ change in the relative phase of the reflection coefficient per 1◦ of rotation. The sensor has an angular measurement range from −90◦ to +90◦. The sensor—a stator fabricated on a 0.5-mm-thick Rogers RT5880 substrate and three rotors fabricated on a 1.5-mm-thick Rogers RT5880, a 1-mmthick FR4, and a 0.5-mm-thick Rogers RT5880—can effectively detect the direction of rotation, measure the angle of rotation and angular velocity with reasonable accuracy.

  • A literature survey of the influence of preform reheating and stretch blow molding with hot mold process parameters on the properties of PET containers. Part I.
    • Waldemar Karaszewski
    • Paweł Wawrzyniak
    2020 Pełny tekst Polimery

    The hot fill process is an inexpensive conventional filling technology for high-acidity products (pH < 4.5). It allows certain drinks (sensitive beverages such as fruit and vegetable juices, nectars, soft drinks, vitaminized water) to be stored at ambient temperature without the need for chemical preservatives. The primary feature of the bottles used in the hot fill process is their temperature stability, i.e. the ability to retain the shape of the bottle at the filling temperature. From a mechanical point of view, the thermal stability of PET bottles manufactured by the ISBM process is determined by the mechanical and thermal response of the blown preforms. From a microscopic point of view, the strongest influences on the mechanical and thermal properties of PET bottles are the orientation and crystallisation processes. From a technological point of view, the properties of PET bottles after manufacture by the stretch blow moulding process is mainly determined by the initial structure of the PET preform, the geometry and temperature distribution of the preform, the geometry of the blow mould and technological parameters of the blowing moulding process. The paper presents a wide analysis of the literature on the modified blow molding process with simultaneous stretching of PET material for storing hot filled drinks.

  • A literature survey of the influence of preform reheating and stretch blow moulding with hot mould process parameters on the properties of PET containers – part 2.
    • Waldemar Karaszewski
    • Paweł Wawrzyniak
    2020 Pełny tekst Polimery

    The hot fill process is an inexpensive conventional filling technology for high-acidity products (pH < 4.5). It allows certain drinks (sensitive beverages such as fruit and vegetable juices, nectars, soft drinks, vitaminised water) to be stored at ambient temperature without the need for chemical preservatives. The primary feature of the bottles used in the hot fill process is their temperature stability, i.e. the ability to retain the shape of the bottle at the filling temperature. From a mechanical point of view, the thermal stability of PET bottles manufactured by the ISBM process is determined by the mechanical and thermal response of the blown preforms. From a microscopic point of view, the strongest influences on the mechanical and thermal properties of PET bottles are the orientation and crystallisation processes. From a technological point of view, the properties of PET bottles after manufacture by the stretch blow moulding process is mainly determined by the initial structure of the PET preform, the geometry and temperature distribution of the preform, the geometry of the blow mould and technological parameters of the blowing moulding process. The paper presents a wide analysis of the literature on the modified blow molding process with simultaneous stretching of PET material for storing hot filled drinks.

  • A Loophole of All ‘Loophole-Free’ Bell-Type Theorems
    • Marek Czachor
    2020 Pełny tekst Foundations of Science

    Bell’s theorem cannot be proved if complementary measurements have to be represented by random variables which cannot be added or multiplied. One such case occurs if their domains are not identical. The case more directly related to the Einstein–Rosen–Podolsky argument occurs if there exists an ‘element of reality’ but nevertheless addition of complementary results is impossible because they are represented by elements from different arithmetics. A naive mixing of arithmetics leads to contradictions at a much more elementary level than the Clauser–Horne–Shimony–Holt inequality.

  • A Measurable Selector in Kadison’s Carpenter’s Theorem
    • Marcin Bownik
    • Marcin Szyszkowski
    2020 Pełny tekst CANADIAN JOURNAL OF MATHEMATICS-JOURNAL CANADIEN DE MATHEMATIQUES

    We show the existence of a measurable selector in Carpenter’s Theorem due to Kadison. This solves a problem posed by Jasper and the first author in an earlier work. As an application we obtain a characterization of all possible spectral functions of shift-invariant subspaces of L 2 (R d ) and Carpenter’s Theorem for type I ∞ von Neumann algebras.

  • A measurement method for capacitive sensors based on a versatile direct sensor-to-microcontroller interface circuit
    • Zbigniew Czaja
    2020 Pełny tekst MEASUREMENT

    In the paper, there is presented a new time-domain measurement method for determining the capacitance values of capacitive sensors, dedicated, among others, to capacitive relative humidity sensors. The method is based on a versatile direct sensor-to-microcontroller interface for microcontrollers with internal analog comparators (ACs) and with precision voltage reference sources, e.g. digital-to-analog converters (DACs). The reference source can be replaced by a resistive divider attached to the negative input of the AC. The interface circuit consists only of a reference resistor Rr, a given capacitive sensor working as a voltage divider, and a microcontroller (its peripherals: AC, timer, DAC, I/O pins). A prototype of the proposed complete solution of a compact capacitive smart sensor based on an 8-bit ATXmega32A4 microcontroller has been developed and tested. The maximum possible relative inaccuracy of an indirectly measurable capacitance was analysed, and experimental research was also performed. The results confirmed that the relative errors of value determination for a capacitive sensor are less than ±0.06%, which corresponds to a capacitance measurement accuracy of less than 0.1 pF for a range of measured capacity values from 100 pF to 225 pF, which in turn corresponds to at least a 0.5% relative humidity resolution for commercial capacitive RH sensors (e.g. TE Connectivity HS1101LF and Philips H1).

  • A modelling approach to the transport support for the harvesting and transportation complex under uncertain conditions
    • Ievgen Medvediev
    • Peter Eliseyev
    • Iryna Lebid
    • Olha Sakno
    2020 Pełny tekst IOP Conference Series: Materials Science and Engineering

    The article proposes a modelling approach based on structural and parametric identification of the transport support of the harvesting and transportation complex. The efficiency and effectiveness of the proposed methods of structural and parametric identification for the development of a system for harvesting and transportation complex operation has been proved. A mathematical model based on fuzzy logic has been developed. It reflects the interaction and interference of the weather-climatic, technical and technological parameters of transport support and its elements. A simulation method of transport support for harvesting and transport complex has been developed. The basis of the method is an algorithm for constructing a flow chart for the transport system operation consisting of structural and parametric identification levels and a mathematical model for the winter wheat harvesting transportation. A special feature of the method is the consideration of the weather-climatic, technical and technological parameters of the harvesting-transportation complex.

  • A new concept of PWM duty cycle computation using the Barycentric Coordinates in a Three-Dimensional voltage vectors arrangement
    • Paweł Szczepankowski
    • Nikolai Poliakov
    • Denis Vertegel
    • Krzysztof Szwarc
    • Ryszard Strzelecki
    2020 Pełny tekst IEEE Access

    The paper presents a novel approach to the Pulse Width Modulation (PWM) duty cycle computing for complex or irregular voltage vector arrangements in the two (2D) and three–dimensional (3D) Cartesian coordinate systems. The given vectors arrangement can be built using at least three vectors or collections with variable number of involved vectors (i.e. virtual vectors). Graphically, these vectors form a convex figure, in particular, a triangle or a tetrahedron. The reference voltage vector position inside that figure can be expressed by the barycentric coordinates, which are calculated using the second (2D case) or the third–degree determinant (3D case) – without trigonometry and angles. Thus, the speed of the PWM duty cycle computation rises significantly. The use of the triangle area or the tetrahedron volume, instead of the standard vector projection also permits for a well–defined and universal approach to identifying the reference vector position, especially for converters with complex and/or deformed space–vector diagrams (i.e. floating DC–link, multisource DC–link). The proposed computation scheme is based on simple instructions without trigonometry thereby, the DSP processor, or digital solution for field–programmable gate array, can fast–perform this operation using atomic operations. The aim of the presented considerations is not a novel PWM modulation, but a computable idea of a general calculation scheme for cases in which the distribution of vectors is non-trivial. A detailed algebraic and geometric analysis, as well as mathematical proofs on the total consistency of the results with the standard projection method, are also included. Subsequently, the Three–Dimensional Space Vector Modulation (3D–SVM), is considered as a special background to present a novel approach.

  • A new construction of shell-and-tube heat exchanger with impinging jets and minichannels technologies for heat recovery from gases – experimental analysis
    • Jan Wajs
    • Roksana Bochniak
    • Aleksandra Gołąbek
    • Tomasz Kura
    2020

    A dynamic development of technologies allowing waste heat utilization is observed in a correspondence with a pro-ecological approach of the zero waste idea. Such approach becomes the most demanding in the area of low-temperature was heat sources, especially gaseous media. Till now, they were usually not utilized due to unfavorable thermal conditions and high costs. Therefore, the zero waste approach directs research on techniques for heat exchange intensification and increasing heat transfer coefficients. In many cases, it is connected with the compact heat exchangers oriented on the low-temperature heat recovery from gaseous sources. Passive intensification methods, characterized by low energy consumption are primarily desirable. The shell-and-tube heat exchanger is a type of commonly applied unit in various industry branches, that is why it is considered as the most suitable for improvements. The passive techniques, implemented in it, are very often connected with various types of inserts in the bundle of tubes, which intensify the heat exchange process on the gas side and are a relatively simple modification even of existing heat exchangers. The inserts are of various shapes, optimized toward particular applications and sometimes combined with other techniques. Following the pro-ecological approach, the authors proposed an innovative shell-and-tube heat exchanger a new type of inserts, designed to transfer high heat fluxes. Proposed construction based on the previous experiences with the impinging jets technology, which confirmed its validity in the cylindrical heat exchangers. Novelty of the tube inserts relies on generation of jets impinging on the heat exchange surface. To enhance a compactness of the heat exchanger, the minichannels technology was also implemented - the inlet diameter of single perforated tube is 2 mm. In this paper the construction and principles of operation of described shell-and-tube heat exchanger were discussed. The experimental stand and investigations of heat exchanger thermal performance in a single-phase convection in the gas-liquid system were presented. Analysis of obtained data provides the basis for further development of a correlation describing the Nusselt number for shell-and-tube heat exchangers with impinging jet technique.

  • A new hyperbolic-polynomial higher-order elasticity theory for mechanics of thick FGM beams with imperfection in the material composition
    • Mohammad Malikan
    • Victor Eremeev
    2020 Pełny tekst COMPOSITE STRUCTURES

    A drawback to the material composition of thick functionally graded materials (FGM) beams is checked out in this research in conjunction with a novel hyperbolic‐polynomial higher‐order elasticity beam theory (HPET). The proposed beam model consists of a novel shape function for the distribution of shear stress deformation in the transverse coordinate. The beam theory also incorporates the stretching effect to present an indirect effect of thickness variations. As a result of compounding the proposed beam model in linear Lagrangian strains and variational of energy, the system of equations is obtained. The Galerkin method is here expanded for several edge conditions to obtain elastic critical buckling values. First, the importance of the higher‐order beam theory, as well as stretching effect, is assessed in assorted tabulated comparisons. Next, with validations based on the existing and open literature, the proposed shape function is evaluated to consider the desired accuracy. Some comparative graphs by means of well‐known shape functions are plotted. These comparisons reveal a very good compliance. In the final section of the paper, based on an inappropriate mixture of the SUS304 and Si3C4 as the first type of FGM beam (Beam‐I) and, Al and Al2O3 as the second type (Beam‐II), the results are pictured while the beam is kept in four states, clamped–clamped (C–C), pinned–pinned (S–S), clamped-pinned (C–S) and in particular cantilever (C–F). We found that the defect impresses markedly an FGM beam with boundary conditions with lower degrees of freedom.

  • A new look at the statistical identification of nonstationary systems
    • Maciej Niedźwiecki
    • Marcin Ciołek
    • Artur Gańcza
    2020 Pełny tekst AUTOMATICA

    The paper presents a new, two-stage approach to identification of linear time-varying stochastic systems, based on the concepts of preestimation and postfiltering. The proposed preestimated parameter trajectories are unbiased but have large variability. Hence, to obtain reliable estimates of system parameters, the preestimated trajectories must be further filtered (postfiltered). It is shown how one can design and optimize such postfilters using the basis function framework. The proposed solution to adaptive tuning of postfilter settings is based on parallel estimation and cross-validatory analysis. When compared with the classical solutions to the problem of parameter tracking, the new approach offers, without compromising good tracking performance, significant computational savings, higher numerical robustness and greater flexibility.

  • A New Method of Noncausal Identification of Time-varying Systems
    • Maciej Niedźwiecki
    • Marcin Ciołek
    • Artur Gańcza
    • Piotr Kaczmarek
    2020 Pełny tekst

    The paper shows that the problem of noncausal identification of a time-varying FIR (finite impulse response) sys- tem can be reformulated, and solved, as a problem of smoothing of the preestimated parameter trajectories. Characteristics of the smoothing filter should be chosen so as to provide the best trade- off between the bias and variance of the resulting estimates. It is shown that optimization of the smoothing operation can be performed adaptively using the parallel estimation technique.

  • A nontargeted approach to determine the authenticity of Ginkgo biloba L. plant materials and dried leaf extracts by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and chemometrics
    • Meryl Cruz
    • Benjamin J. Place
    • Laura J. Wood
    • Aaron Urbas
    • Andrzej Wasik
    • Werickson Fortunato de Carvalho Rocha
    2020 Pełny tekst ANALYTICAL AND BIOANALYTICAL CHEMISTRY

    The lack of stringent regulations regarding raw materials for herbal supplements used for medicinal purposes has been a constant challenge in the industry. Ginkgo biloba L. leaf extracts attract consumers because of the supposed positive effect on mental performance and memory. Supplements are produced using dried leaf materials and standardized leaf extracts such as EGb 761. Adulteration of Ginkgo biloba L. plants and extracts are becoming more and more common practice due to economically driven motivation from increasing demand in the market and the high cost of raw materials and production. Reinforcement in quality control (QC) to avoid adulterations is necessary to ensure the efficacy of the supplements. In this study, liquid chromatographyhigh-resolution mass spectrometry (LC-HRMS) was used with principal component analysis (PCA) as an unsupervised exploratory method to analyze, identify, and evaluate the adulterated Ginkgo biloba L. plant materials and dried leaf extracts using the PCA scores and loadings obtained and compound identification.

  • A note on polynomial algorithm for cost coloring of bipartite graphs with Δ ≤ 4
    • Krzysztof Giaro
    • Marek Kubale
    2020 Pełny tekst Discussiones Mathematicae Graph Theory

    In the note we consider vertex coloring of a graph in which each color has an associated cost which is incurred each time the color is assigned to a vertex. The cost of coloring is the sum of costs incurred at each vertex. We show that the minimum cost coloring problem for n-vertex bipartite graph of degree ∆≤4 can be solved in O(n^2) time. This extends Jansen’s result [K.Jansen,The optimum cost chromatic partition problem, in: Proc. CIAC’97,Lecture Notes in Comput. Sci. 1203 (1997) 25–36] for paths and cycles to subgraphs of biquartic graphs.

  • A novel concept of negative CO2 emission power plant for utilization of sewage sludge
    • Paweł Ziółkowski
    • Janusz Badur
    • Halina Pawlak-kruczek
    • Lukasz Niedzwiecki
    • Mateusz Kowal
    • Krystian Krochmalny
    2020

    Carbon Capture and Storage (CSS) technology is considered an important “bridge technology”, allowing effective abatement of CO2 emissions for power units using fossil fuels. However, if biomass is used in a power plant, equipped with CCS system, negative CO2 emissions can be achieved. In practice, wide development of such technologies would enable not only reduction of CO2 emissions, but also reversal of the harm done so far. In the long term, wide application of technologies with carbon-negative emissions could allow coming back to pre-industrial concentrations of CO2 in the atmosphere. Sewage sludge is a residue of the wastewater processing, that is a biologically active and consists of water, organic matter, including dead and alive pathogens, as well as organic and inorganic contaminants such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Due to the nature of sewage sludge and its possible influence on human health and wellbeing, it is a subject of various regulations. Currently, sewage sludge is considered a biomass, according to the new Polish act on renewable energy sources from 20th of February 2015 and its novel version from 19th of July 2019. This study presents a novel approach, that aims at assessing feasibility of the concept of a negative CO2 emission power plant, based on steam gasification of sewage sludge, subsequent combustion of the producer gas in a gas turbine with spray-ejector condenser. This novel solution offers an efficient way to convert the chemical energy in the sewage sludge and, in the same time, compress and capture CO2. Possibility to utilize sewage sludge is an additional advantage of the proposed solution. For example: composition and calorific value of the dry producer gas, determined experimentally, are as follows: YCO=0.133; YCO2=0.593; YCH4=0.117; YCnHm=0.08; YH2=0.051 and LHV=16.43 MJ/kg.

  • A Novel Method for the Deblurring of Photogrammetric Images Using Conditional Generative Adversarial Networks
    • Paweł Burdziakowski
    2020 Pełny tekst Remote Sensing

    The visual data acquisition from small unmanned aerial vehicles (UAVs) may encounter a situation in which blur appears on the images. Image blurring caused by camera motion during exposure significantly impacts the images interpretation quality and consequently the quality of photogrammetric products. On blurred images, it is difficult to visually locate ground control points, and the number of identified feature points decreases rapidly together with an increasing blur kernel. The nature of blur can be non-uniform, which makes it hard to forecast for traditional deblurring methods. Due to the above, the author of this publication concluded that the neural methods developed in recent years were able to eliminate blur on UAV images with an unpredictable or highly variable blur nature. In this research, a new, rapid method based on generative adversarial networks (GANs) was applied for deblurring. A data set for neural network training was developed based on real aerial images collected over the last few years. More than 20 full sets of photogrammetric products were developed, including point clouds, orthoimages and digital surface models. The sets were generated from both blurred and deblurred images using the presented method. The results presented in the publication show that the method for improving blurred photo quality significantly contributed to an improvement in the general quality of typical photogrammetric products. The geometric accuracy of the products generated from deblurred photos was maintained despite the rising blur kernel. The quality of textures and input photos was increased. This research proves that the developed method based on neural networks can be used for deblur, even in highly blurred images, and it significantly increases the final geometric quality of the photogrammetric products. In practical cases, it will be possible to implement an additional feature in the photogrammetric software, which will eliminate unwanted blur and allow one to use almost all blurred images in the modelling process.