2019 - Publications Repository - Gdańsk University of Technology

Show publications from the year

Publications from the year 2019

Show all

Low-Coherence Interferometric Fiber-Optic Sensors with Potential Applications as Biosensors
- Marzena Hirsch
- Daria Majchrowicz
- Paweł Wierzba
- Matthieu Weber
- Mikhael Bechelany
- Małgorzata Szczerska
2019 Full text
Fiber-optic Fabry-Pérot interferometers (FPI) can be applied as optical sensors, and excellent measurement sensitivity can be obtained by fine-tuning the interferometer design. In this work, we evaluate the ability of selected dielectric thin films to optimize the reflectivity of the Fabry-Pérot cavity. The spectral reflectance and transmittance of dielectric films made of titanium dioxide (TiO2) and aluminum oxide (Al2O3) with thicknesses from 30 to 220 nm have been evaluated numerically and compared. TiO2 films were found to be the most promising candidates for the tuning of FPI reflectivity. In order to verify and illustrate the results of modelling, TiO2 films with the thickness of 80 nm have been deposited on the tip of a single-mode optical fiber by atomic layer deposition (ALD). The thickness, the structure, and the chemical properties of the films have been determined. The ability of the selected TiO2 films to modify the reflectivity of the Fabry-Pérot cavity, to provide protection of the fibers from aggressive environments, and to create multi-cavity interferometric sensors in FPI has then been studied. The presented sensor exhibits an ability to measure refractive index in the range close to that of silica glass fiber, where sensors without reflective films do not work, as was demonstrated by the measurement of the refractive index of benzene. This opens up the prospects of applying the investigated sensor in biosensing, which we confirmed by measuring the refractive index of hemoglobin and glucose.
Low-Dimensional Magnetic Semimetal Cr0.65Al1.35Se3
- Madalynn Marshall
- Joanna Blawat
- Lingyi Xing
- Michał Winiarski
- Tomasz Klimczuk
- Rongying Jin
- Weiwei Xie
2019 INORGANIC CHEMISTRY
While exploring novel magnetic semiconductors, the new phase Cr0.65Al1.35Se3 was discovered and characterized by both structural and physical properties. Cr0.65Al1.35Se3 was found to crystallize into orthorhombic CrGeTe3-type structure with space group Pnma (no. 62). Vacancies and mixed occupancies were tested, and the results show that one of the 4c sites accommodates a mixture of Cr and Al atoms, while the other 4c site is fully occupied by Al atoms. Unique structural features include a T-shaped channel network created from the edge-sharing Cr/Al@Se6 and Al@Se4 polyhedra and a zipper effect of the puckered Se atoms inside the columnar channels. The round peak observed in the temperature-dependent magnetic susceptibility (χg) plot at ∼8(1) K corresponds to the antiferromagnetic-type transition in Cr0.65Al1.35Se3. However, the positive θCW indicates an additional ferromagnetic interaction, which is highly likely due to the complex magnetic structure arising from the mixed Cr/Al occupancies on the 4c site. Electrical resistivity measurements confirm that Cr0.65Al1.35Se3 is a semimetal with a positive magnetoresistance. Here we present the characterization and determination of the crystal structure and physical properties for this new material.
Low-energy positron scattering from gas-phase benzene
- Jan Franz
- Małgorzata Franz
2019 Full text EUROPEAN PHYSICAL JOURNAL D
In this paper we are presenting calculations of the elastic cross section of positrons with gas-phase benzene for the energy range from 0.25 eV to 9.0 eV. The calculations are done with the molecular R-matrix method for positron-scattering from poly-atomic molecules using a scaling factor to scale the electron-positron interaction. The scaling factor influences the position of the poles of the R-matrix. We adjust the scaling factor is such a way, that the position of the lowest pole is similar to the proposed binding energy of around 150 meV, given by [J.A. Young, C.M. Surko, Phys. Rev. Lett 99, 133201 (2007)]. Below the threshold for positronium formation, we calculate elastic cross section in good agreement with experimental cross sections. Above the threshold for positronium formation we use the difference between the experimental total cross section data and our computed elastic cross section to provide a first estimation of the cross section for positronium formation.
Low-Power WSN System for Honey Bee Monitoring
- Tymoteusz Cejrowski
- Julian Szymanski
- Andrzej Sobecki
- David Gil
- Higinio Mora
2019
The paper presents a universal low-power system for biosensory data acquisition in scope of bees monitoring. We describe the architecture of the system, energy-saving components as well as we discuss the selection of used sensors. The work focuses on energy optimization in a scope of wireless communication. A custom protocol was implemented, which is the basis for presented energy-efficient devices. Data exchange process during network initialization and measurement collection was presented. The core principles are devices synchronization and parallel clocks. Devices wake up in their time slot in order to exchange data. For the energy consumption tests, Keysight N6705B power analyzer was used to draw accurate current intake characteristic. The most demanding operations in terms of power consumption were communication and microphone recordings. The performance of devices in case of non-optimized operation, i.e. when optimization techniques are switched off, was compared. It has been shown that devices equipped with 2200 mAh battery can operate continuously for 2 years and 7 months, which gives 3600% increase in operating days compared to the non-optimized case.
Low-Profile ESPAR Antenna for RSS-Based DoA Estimation in IoT Applications
- Mateusz Burtowy
- Mateusz Rzymowski
- Łukasz Kulas
2019 Full text IEEE Access
In this paper, we have introduced a low-profile electronically steerable parasitic array radiator (ESPAR) antenna that can successfully be used to estimate the direction-of-arrival (DoA) of incoming signals in wireless sensor network (WSN) applications, in which the height of the complete antenna has to be low. The proposed antenna is over three times lower than high-profile ESPAR antenna designs currently available in the literature for the DoA estimation; it can provide eight unique main beam directions and relies on simplified beam steering, which makes it applicable to simple and inexpensive WSN nodes. Measurements using our fabricated ESPAR antenna prototype indicate that relying solely on the received signal strength values recorded at the antenna output port, it is possible to achieve accurate DoA estimation results with error levels similar to those available for high-profile ESPAR antennas relying on the similar energy-efficient simplified beam steering concept and having 12 unique main beam directions. As a consequence, the overall time required for the DoA estimation using the proposed antenna can be reduced by 33%.
Low-Temperature Requirements for Bitumen in Central East European Road Construction
- Piotr Radziszewski
- Michał Sarnowski
- Jan Król
- Piotr Pokorski
- Piotr Jaskuła
- Dawid Ryś
- Marek Pszczoła
2019 Full text Baltic Journal of Road and Bridge Engineering
The paper presents the proposition of special assessment of lowtemperature requirements for bitumens in the region of Central and Eastern Europe where there is a moderate transitional area from sea to the continental type of climate. The results of the research program conducted on the road neat bitumens, Styrene-Butadiene-Styrene polymer and polymer-rubber modified bitumen, and multigrade bitumen types were presented and discussed. Based on the Superior Performing Asphalt Pavements Performance Grade procedure for low temperatures, climatic zones in Poland were developed and compared to analogous zones for other countries from the Central and Eastern Europe region as Estonia and Belarus. The results of functional Performance Grade tests and European standard test of bituminous binders were analysed. It was concluded that some of the bitumens were not meet the performance requirements in the range of low temperatures by Superior Performing Asphalt Pavements Superpave specification and the low-temperature properties of those bitumens should be improved.
LS-DYNA simulations of the impacts of a 38-ton Heavy Goods Vehicle into a road cable barrier
- Krzysztof Wilde
- Dawid Bruski
- Stanisław Burzyński
- Jacek Chróścielewski
- Łukasz Pachocki
- Wojciech Witkowski
2019
Nowadays, more and more attention is being paid to safety on roads and motorways. It is due to the continuous development of road and motorway network and a significant increase of the number of vehicles on roads. To meet the expectations of improving road safety in Poland, the Road Innovations Development (RID) research programme was implemented in 2016. The aim of the RID 3A - Road Safety Equipment (RoSE) project is a comprehensive analysis of various road restraint systems and various types of road safety equipment installed on roads and bridges. The RID 3B - Effect of time and operating conditions of the durability and functionality of the elements of road safety (LifeRoSE) complementary project is aimed at developing innovative and comprehensive road management methodology for road safety equipment and traffic management measures. Part of the aforementioned projects is a thorough study of safety barriers based, among others, on full-scale crash tests and a number of numerical simulations using LS-DYNA. The aim of the paper is to assess the crashworthiness of a road cable barrier during an impact of a Heavy Goods Vehicle (HGV) weighing 38 tons. A numerical model of the safety device was developed and validated with a full-scale crash test. Based on this computational model, a series of virtual crash tests were carried out in which the HGV collides with the barrier under various impact conditions. Some of the cases will be compared with real accident outcome that took place on highway in Poland.
MACHINE LEARNING SYSTEM FOR AUTOMATED BLOOD SMEAR ANALYSIS
- Michał Grochowski
- Michał Wąsowicz
- Agnieszka Mikołajczyk
- Mateusz Ficek
- Marek Kulka
- Maciej Wróbel
- Małgorzata Szczerska
2019 Full text Metrology and Measurement Systems
In this paper the authors propose a decision support system for automatic blood smear analysis based on microscopic images. The images are pre-processed in order to remove irrelevant elements and to enhance the most important ones - the healthy blood cells (erythrocytes) and the pathologic (echinocytes). The separated blood cells are analyzed in terms of their most important features by the eigenfaces method. The features are the basis for designing the neural network classifier, learned to distinguish between erythrocytes and echinocytes. As the result, the proposed system is able to analyze the smear blood images in fully automatic manner and to deliver information on the number and statistics of the red blood cells, both healthy and pathologic. The system was examined on two case studies, the canine and human blood, and then confronted with the experienced medicine specialists. The accuracy of red blood cells classification into erythrocytes and echinocytes reaches 96%.
Machine Learning Techniques in Concrete Mix Design
- Patryk Ziółkowski
- Maciej Niedostatkiewicz
2019 Full text Materials
Concrete mix design is a complex and multistage process in which we try to find the best composition of ingredients to create good performing concrete. In contemporary literature, as well as in state-of-the-art corporate practice, there are some methods of concrete mix design, from which the most popular are methods derived from The Three Equation Method. One of the most important features of concrete is compressive strength, which determines the concrete class. Predictable compressive strength of concrete is essential for concrete structure utilisation and is the main feature of its safety and durability. Recently, machine learning is gaining significant attention and future predictions for this technology are even more promising. Data mining on large sets of data attracts attention since machine learning algorithms have achieved a level in which they can recognise patterns which are difficult to recognise by human cognitive skills. In our paper, we would like to utilise state-of-the-art achievements in machine learning techniques for concrete mix design. In our research, we prepared an extensive database of concrete recipes with the according destructive laboratory tests, which we used to feed the selected optimal architecture of an artificial neural network. We have translated the architecture of the artificial neural network into a mathematical equation that can be used in practical applications.
MACHINE LEARNING–BASED ANALYSIS OF ENGLISH LATERAL ALLOPHONES
- Magdalena Piotrowska
- Grazina Korvel
- Bożena Kostek
- Tomasz Ciszewski
- Andrzej Czyżewski
2019 Full text International Journal of Applied Mathematics and Computer Science
Automatic classification methods, such as artificial neural networks (ANNs), the k-nearest neighbor (kNN) and selforganizing maps (SOMs), are applied to allophone analysis based on recorded speech. A list of 650 words was created for that purpose, containing positionally and/or contextually conditioned allophones. For each word, a group of 16 native and non-native speakers were audio-video recorded, from which seven native speakers’ and phonology experts’ speech was selected for analyses. For the purpose of the present study, a sub-list of 103 words containing the English alveolar lateral phoneme /l/ was compiled. The list includes ‘dark’ (velarized) allophonic realizations (which occur before a consonant or at the end of the word before silence) and 52 ‘clear’ allophonic realizations (which occur before a vowel), as well as voicing variants. The recorded signals were segmented into allophones and parametrized using a set of descriptors, originating from the MPEG 7 standard, plus dedicated time-based parameters as well as modified MFCC features proposed by the authors. Classification methods such as ANNs, the kNN and the SOM were employed to automatically detect the two types of allophones. Various sets of features were tested to achieve the best performance of the automatic methods. In the final experiment, a selected set of features was used for automatic evaluation of the pronunciation of dark /l/ by non-native speakers.
Macromodels for Efficient Analysis of Open-Region Problems Using the Finite Element Method
- Damian Szypulski
- Martyna Mul
- Krzysztof Nyka
- Grzegorz Fotyga
2019
This paper presents a local model-order reduction, called macromodeling, applied to speed-up the simulations of open-region problems, analyzed by means of finite element method. This technique is illustrated by a numerical example, which deals with a dielectric resonator antenna (DRA). The obtained results show that the proposed approach is reliable and can significantly increase the standard finite element method efficiency.
Magnetic photocatalysts for water treatment
- Anna Zielińska-Jurek
- Szymon Dudziak
- Zuzanna Bielan
- Agnieszka Sulowska
- Izabela Malinowska
- Izabela Wysocka
2019
The concept of magnetic photocatalysts with separation function requires ferromagnetic material with high magnetic susceptibility to an external magnetic field to enable recycling of composite nanoparticles. Currently, much attention is devoted to functionalization of photocatalyst using MFe2O3, where M =Fe, Zn, Co, Mn. However direct contact between photocatalyst and magnetic iron oxide particles leads to photodissolution of iron ions into the solution during irradiation and, as a consequence, nanocomposite poisoning as well loosing the magnetic and photocatalytic properties. In order to overcome leaching of iron ions into the solution core addition of silica, polymer or carbon inert layer between the magnetic core and the TiO2 shell is applied (Fig. 1-b). In this regard, the aim of present study is to better understand the effect of the preparation procedure on magnetic properties and photocatalytic activity of spinel MFe2O3 ferrites. The pH of the solution and corresponding zeta potential was found to be essential for appropriate formation of ferrite core/silica interlayer/TiO2 shell nanocomposite, since the electrical charge controls interactions during functionalization of the magnetic core particles (see in Fig. 2). Further, Pt-Cu metallic particles were deposited on magnetic photocatalyst surface using photodeposition and chemical reduction methods. The correlation between surface properties of magnetic nanocomposites and photocatalytic activities was studied. The effect of the metal loadings on carbamazepine oxidation pathways, and finally its mineralization, measured as total organic carbon (TOC) reduction was investigated. The obtained magnetic photocatalysts were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), specific surface area (BET), diffuse reflectance spectroscopy (DRS) and vibrating sample magnetometer (VSM) analysis. The highest photooxidatation rate of carbamazepine, measured as TOC reduction was observed for Pt-modified magnetic photocatalysts. The enhanced activity was related to a decrease in metal particle size, an increase in the adsorption sites and efficient separation of char ge carriers.
MAGNETOACOUSTIC HEATING AND STREAMING IN A PLASMA WITH FINITE ELECTRICAL CONDUCTIVITY
- Anna Perelomova
2019 Full text TASK Quarterly
Nonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. Plasma is assumed to be an ideal gas with a finite electrical conductivity permeated by a magnetic filed orthogonal to the trajectories of gas particles. the excitation of non-wave modes in the filed of intense magnetoacoustic perturbations, i.e., magnetoaciustic heating and streaming, is discussed. The analysis includes a derivation if instantaneous dynamic equations independent of the spectrum and peridicity of sound.
Magnetyczne fotokatalizatory na bazie TiO2 do degradacji zanieczyszczeń w fazie wodnej
- Zuzanna Bielan
- Anna Zielińska-Jurek
2019
Fotokataliza stanowi alternatywę dla tradycyjnych metod oczyszczania wód i ścieków z trudno degradowalnych zanieczyszczeń organicznych. Zastosowanie TiO2 umożliwia efektywne usuwanie związków chloroorganicznych, alkoholi, kwasów organicznych, pestycydów, barwników, węglowodorów aromatycznych oraz związków powierzchniowo czynnych z fazy wodnej. Poważnym ograniczeniem zastosowania TiO2 na szeroką skalę w procesach oczyszczania ścieków jest zakres promieniowania niezbędny do wzbudzenia fotokatalizatora. Tlenek tytanu(IV) absorbuje prawie wyłącznie promieniowanie UVA. w związku z tym przyjmuje się, że w procesie fotokatalizy z zastosowaniem TiO2 wykorzystane może zostać jedynie 3-5% światła słonecznego. Drugim ważnym aspektem technologicznym jest separacja fotokatalizatora z zawiesiny po procesie oczyszczania. Ze względu na wielkość ziaren stosowanych fotokatalizatorów, zazwyczaj poniżej 100 nm, trudno jest przeprowadzić efektywnie separację, zaś koagulacja, ultrafiltracja bądź też separacja membranowa mogą generować dodatkowe koszty dla operacji jednostkowej odzysku fotokatalizatora. Przedstawiona metodyka otrzymywania warstwowych fotokatalizatorów o strukturze rdzeń-otoczka, bazujących na różnicy ładunków powierzchniowych pozwala na rozwiązanie problemu separacji za pomocą wykorzystania zewnętrznego pola magnetycznego. Dodatkowo stanowi ona punkt wyjścia do dalszych modyfikacji, np. niemetalami bądź metalami, które pozwolą na zwiększenie aktywności TiO2 w świetle widzialnym.
Makroskopowe modele ruchu potoku pojazdów na odcinkach międzywęzłowych autostrad i dróg ekspresowych
- Aleksandra Romanowska
2019 Full text
Autostrady i drogi ekspresowe stanowią rdzeń sieci drogowej kraju, zapewniając podstawowe międzynarodowe i międzyregionalne połączenia transportowe. Dynamiczny rozwój sieci tych dróg w Europie i USA w drugiej połowie XX wieku spowodował. że inżynierowie ruchu drogowego i naukowcy zaczęli obserwować ruch pojazdów na tych drogach poszukując: modeli opisujących ruch potoku pojazdów, metod szacowania przepustowości i metod oceny warunków ruchu na tych drogach. W rezultacie powstała szeroka dziedzina wiedzy zwana teorią ruchu potoku pojazdów , która przez lata zyskała solidne podstawy teoretyczne i empiryczne. Tymczasem w Polsce o systematycznym rozwoju sieci autostrad i dróg ekspresowych można mówić dopiero od kilkunastu lat. Stąd też dotychczas zainteresowanie badaczy badaniem ruchu potoku pojazdów na autostradach i drogach ekspresowych było raczej niewielkie. Traktując zależność fundamentalną ( zależność między natężeniem, prędkością i gęstością potoku pojazdów) jako podstawę teorii ruchu potoku pojazdów, polskie badania ograniczają się właściwie do badań prof. Krystka z lat 70. i 80. ubiegłego wieku. Zainteresowanie zagadnieniem wróciło dopiero w ostatnich latach, w rezultacie rozpoczęcia projektu RID-2B. Pozostała jednak ogromna luka w krajowych badaniach względem badań zagranicznych. Wypełnianie powstałej luki powinno się zacząć od podstaw, a więc badania fundamentalnej zależności pomiędzy natężeniem, prędkością i gęstością. Taki też cel postawiono w pracy, badając i modelując ruch potoku pojazdów na odcinkach międzywęzłowych autostrad i dróg ekspresowych w Polsce.
Maksymalna elastyczność pracy bloków parowych
- Badur Janusz
- Kowalczyk Tomasz
- Mateusz Bryk
- Kamil Banaś
- Michał Stajnke
- Bartosz Kraszewski
- Paweł Ziółkowski
- Piotr Ziółkowski
2019 Energetyka, problemy energetyki i gospodarki paliwowo - energetycznej
W artykule przedstawiono propozycję przyspieszenia startów turbiny parowej poprzez właściwe doprowadzanie pary w trakcie stanów niestacjonarnych. Badano najbardziej wytężone miejsca w urządzeniu, przy uwzględnieniu tradycyjnej hipotezy Hubera-Missesa-Hencky, jak i hipotezy Burzyńskiego. W przypadku licznych startów coraz większe znaczenie odgrywają naprężenia termiczne, dla których najważniejsze są składowe normalne naprężeń, w odróżnieniu od składowych stycznych konwencjonalnie, będących podstawą obliczeń naprężeń zredukowanych na podstawie hipotezy Hubera-Missesa-Hencky. Obliczenia nakierowane na uzyskanie maksymalnej elastyczności przeprowadzono z wykorzystaniem numerycznego narzędzia thermal-FSI, które jednocześnie analizują płyn i konstrukcję, tak aby w pełni sprzęgnąć ze sobą pola temperatury i tym samym dokładniej wyznaczyć naprężenia w konstrukcji.
Manifest prysznicowy: jakiej chciałbym sztuki, wideo, wystawa Wolne pokoje: Fiks, Gdańsk 2019
- Patryk Różycki
2019
FIKS (wystawa zbiorowa) Przemiany współczesnych społeczeństw i zachwianie poczucia bezpieczeństwa mają swoje odbicie w pewnych zachowaniach jednostek. Wynika to nie rzadko z frustracji, poczucia winy lub lęku. Gdzieś tam na innym poziomie świadomości nawykowe mechanizmy obronne niekoniecznie muszą być patologiczne. Codzine rytualy, metody, różnorodność osobistych tarczy, systemów i amuletów, fazy, cykle, niekończący sie kołowrotek. Zwykły rytm spanko- jedzonko- do pracy/na zajęcia/na bezrobocie. Właściwie wszystko ok dopóki ma się pewność, że jeszcze jest to zdrowa rutyna, a nie błędne koło z którego nie można się wyrwać. Klasyczna forma powtarzalności, bo jakoś trzeba żyć. Jednak telefon nie skrolluje się sam co 15 min. Jak zahipnotyzowani nawet nie pamiętamy, kiedy zaczęliśmy grać w grę, gotowi jednak grać do końca, jak orkiestra na Tytanic’u, kolekcjonować naklejki z Biedronki, a bez pomalowanych paznokci nie wychodzić z domu. Biegnąc jednolitą ścieżką, nie patrzy się na boki i powtarza słowa, którym nigdy nie bylo okazji przysłuchać się uważnie. Niezła wkrętka. Czy setny raz wykonane czynności swoje znaczenie tracą, czy na znaczeniu zyskują? Czym jest forma do której dążymy? Na czym się skupiamy? Czemu się poświęcamy? Co próbujmy kontrolować? O czym zapomnieć? Czym są te przyzwyczajenia? Może mantrą codzienności, która pozwala utrzymać zdrowy rozsądek? Może tracimy zmysły, bo w nawyk weszła kompletnie irracjonalna czynność-niepojęta ale za nic nie mozna z niej zrezygnowac?
Mapping knowledge risks: towards a better understanding of knowledge management
- Susanne Durst
- Małgorzata Zięba
2019 Full text Knowledge Management Research & Practice
This conceptual paper aims to identify, present, and analyze potential knowledge risks organizations might face. With the growing complexity of organizational environments and the plethora of new knowledge risks emerging, this critical but under-researched field of knowledge management (KM) deserves closer attention. The study is based on a critical analysis of the extant literature devoted to knowledge risks, discusses potential outcomes of these risks and proposes a concept map of knowledge risks. The map shows a number of knowledge risks organizations should be aware of. Knowledge risks can be assigned to three categories: human, technological and operational. The research is the first systematic and comprehensive review of knowledge risks at the organizational level. By aggregating and consolidating the knowledge risks covered, the study does not only provide a knowledge risk taxonomy but also promising directions for future research. The study also contributes to a more comprehensive understanding of KM.
Marine autonomous surface ship - control system configuration
- Tomasz Zubowicz
- Krzysztof Armiński
- Anna Witkowska
- Roman Śmierzchalski
2019 Full text IFAC-PapersOnLine
This paper addresses the problem of marine autonomous surface ship (MASS) control. The contribution of the paper is the development of a control system configuration, done assuming fully autonomous MASS operation under distinct operational conditions. The overview of hardware and software selection is included.
Marine propeller shaft bearings under low-speed conditions: water vs. oil lubrication
- Wojciech Litwin
2019 Full text TRIBOLOGY TRANSACTIONS
The bearings used in shipbuilding, hydropower, and water pumps have undergone a metamorphosis in recent decades. Because of environmental regulations, lubrication with grease or mineral oil is prohibited. Thus, the standard solutions include water-lubricated bearings with polymer bushings or sealed systems lubricated with oil. When properly designed, assembled, and operated, bearings can operate reliably for years. However, specific operating conditions, such as a low rotational speed of the shaft, may result in intensive wear and premature failure. In this study, four sliding bearings approved for use in shipbuilding were experimentally tested. The test results showed that the choice of the bearing type has a key effect on friction during low-speed operation. Some of the tested bearings had significant static friction with intense slip-stick phenomena; they should not be used in applications requiring low-speed operation.