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Gdańsk University of Technology

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Publications from the year 2018

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  • Superconducting SrSnP with Strong Sn–P Antibonding Interaction: Is the Sn Atom Single or Mixed Valent?
    • Xin Gui
    • Zuzanna Sobczak
    • Tay-Rong Chang
    • Xitong Xu
    • Angus Huang
    • Shuang Jia
    • Horng-Tay Jeng
    • Tomasz Klimczuk
    • Weiwei Xie
    2018 CHEMISTRY OF MATERIALS

    The large single crystals of SrSnP were prepared using Sn self-flux method. The superconductivity in the tetragonal SrSnP is observed with the critical temperature of ∼2.3 K. The results of a crystallographic analysis, superconducting characterization, and theoretical assessment of tetragonal SrSnP are presented. The SrSnP crystallizes in the CaGaN structure type with space group P4/nmm (S.G. 129, Pearson symbol tP6) according to the single-crystal X-ray diffraction characterization. A combination of magnetic susceptibility, resistivity, and heat capacity measurements confirms the bulk superconductivity with Tc = 2.3(1) K in SrSnP. According to the X-ray photoelectron spectroscopy measurement, the assignments of Sr2+ and P3– are consistent with the chemical valence electron balance principles. Moreover, it is highly likely that Sn atom has only one unusual oxidation state. First-principles calculations indicate the bands around Fermi level are hybridized among Sr d, Sn p, and P p orbitals. The strong Sn–P and Sr–P interactions pose as keys to stabilize the crystallographic structure and induce the superconductivity, respectively. The physics-based electronic and phononic calculations are consistent with the molecular viewpoint. After inclusion of the spin–orbit coupling into the calculation, the band degeneracies at Γ-point in the first Brillouin zone split into two bands, which yield to the van Hove singularities around Fermi level.

  • Superconductivity in the superhard boride WB4.2
    • Elizabeth M. Carnicom
    • Judyta Strychalska-Nowak
    • Piotr Wiśniewski
    • Dariusz Kaczorowski
    • Weiwei Xie
    • Tomasz Klimczuk
    • R.j. Cava
    2018 SUPERCONDUCTOR SCIENCE & TECHNOLOGY

    We show that the superhard boride WB4.2 is a superconductor with a Tc of 2.05(5) K. Temperature-dependent magnetic susceptibility, electrical resistivity, and specific heat measurements were used to characterize the superconducting transition. The Sommerfeld constant γ for WB4.2 is 2.07(3) mJ mol−1 K−2 and the ΔC/γTc=1.56, which is somewhat higher than what is expected for weakly coupled Bardeen–Cooper–Schrieffer type superconductors. The Hc2 versus T plot is linear over a wide temperature range but does show signs of flattening by the lowest temperatures studied and therefore the zero temperature upper critical field (μ0Hc2(0)) for WB4.2 lies somewhere between the linear extrapolation of μ0Hc2(T) to 0 K and expectations based on the Werthamer–Helfand–Hohenberg model.

  • Support for Employees with ASD in the Workplace Using a Bluetooth Skin Resistance Sensor–A Preliminary Study
    • Michał Tomasz Tomczak
    • Marek Wójcikowski
    • Paulina Listewnik
    • Bogdan Pankiewicz
    • Daria Majchrowicz
    • Małgorzata Szczerska
    2018 Full text SENSORS

    The application of a Bluetooth skin resistance sensor in assisting people with Autism Spectrum Disorders (ASD), in their day-to-day work, is presented in this paper. The design and construction of the device are discussed. The authors have considered the best placement of the sensor, on the body, to gain the most accurate readings of user stress levels, under various conditions. Trial tests were performed on a group of sixteen people to verify the correct functioning of the device. Resistance levels were compared to those from the reference system. The placement of the sensor has also been determined, based on wearer convenience. With the Bluetooth Low Energy block, users can be notified immediately about their abnormal stress levels via a smartphone application. This can help people with ASD, and those who work with them, to facilitate stress control and make necessary adjustments to their work environment.

  • Support Product Development Framework by Means of Set of Experience Knowledge Structure (SOEKS) and Decisional DNA
    • Edward Szczerbicki
    • Muhammad Ahmed
    • Cesar Sanin
    2018

    In this paper, we propose a framework to support product development activi-ties by utilizing Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA). This idea will provide a new direction to researchers working on product development, especially designers and manufacturers. They will be working on the same platform and this will be reducing their communication gap. Once the final idea is perceived about product development, it will be easy to de-sign and manufacture it quickly and efficiently. Early consideration of manufac-turing issues can shorten product development cycle time, minimize overall de-velopment cost, and ensure a smooth transition into production. In the product development process, knowledge of previous products and processes is very im-portant as product development requires both knowledge and experience. This framework will store knowledge in the form of experiences of past decisions, and the system will update itself after every decision is taken.

  • Support Vector Machine Applied to Road Traffic Event Classification
    • Maciej Blaszke
    • Bozena Kostek
    2018 Full text MATEC Web of Conferences

    The aim of this paper is to present results of road traffic event signal recognition. First, several types of systems for road traffic monitoring, including Intelligent Transport System (ITS) are shortly described. Then, assumptions of creating a database of vehicle signals recorded in different weather and road conditions are outlined. Registered signals were edited as single vehicle pass by. Using the Matlab-based application a feature vector containing 48 parameters was extracted and analyzed in the context of parameter separability and classification effectiveness employing SVM (Support Vector Machine) algorithm. In conclusion, the classifier developed and its effectiveness were discussed.

  • Supporting Gastroesophageal Reflux Disease Diagnostics by Using Wavelet Analysis in Esophageal pH-Metry
    • Piotr Tojza
    • Grzegorz Redlarski
    • Maria Janiak
    2018 Full text Annals of Computer Science and Information Systems

    This paper presents a new approach to computer supported esophageal pH-metry measurement analysis performed in order to diagnose gastroesophageal reflux disease. In this approach wavelet analysis was used to analyse the esophageal pH-metry course. The research was performed on three groups of pH-metry courses: whole 24-hour pH-metry course, sleep only pH-metry course and 20 minutes after the end of a meal pH-metry course. After performing a 128 level decomposition of the pH-metry course, the W_x was defined as a parameter of extreme differential. This parameter was used to distinguish patients esophageal pH-metry results and on that basis classify patients as healthy or sick. Using this method the sensitivity of 77 % was achieved.

  • Suppression of distortions in signals received from Doppler sensor for vehicle speed measurement
    • Grzegorz Szwoch
    2018 Full text

    Doppler sensors are commonly used for movement detection and speed measurement. However, electromagnetic interference and imperfections in sensor construction result in degradation of the signal to noise ratio. As a result, detection of signals reflected from moving objects becomes problematic. The paper proposes an algorithm for reduction of distortions and noise in the signal received from a simple, dual-channel type of a Doppler sensor. The proposed method is based on examining phase relationship between I/Q channels of the sensor signal. A weighting function is calculated in order to suppress the distortions while preserving energy of the desired signal. Additionally, the proposed algorithm may select signals reflected by objects moving in a specific direction (e.g. towards the sensor). The processed signal may be further analyzed in order to detect signal frequency and compute the object velocity. The results of the experiments show that the proposed approach results in significant reduction of level of noise and interference, allowing for detection and tracking of signals reflected from moving objects.

  • Surface sliding in human abdominal wall numerical models: Comparison of single-surface and multi-surface composites
    • Paweł Michał Bielski
    • Izabela Lubowiecka
    2018

    Determining mechanical properties of abdominal soft tissues requires a coupled experimental-numerical study, but first an appropriate numerical model needs to be built. Precise modeling of human abdominal wall mechanics is difficult because of its complicated multi-layer composition and large variation between specimens. There are several approaches concerning simplification of numerical models, but it is unclear how far one could go to still maintain fairly good results. The study compares behaviour of two different shell models: a simpler one, consisting of a single composite shell incorporating all abdominal wall layers and a more complicated one, consisting of three respective muscle-fascia composites allowed to slide on one another, representing a more realistic abdominal wall behaviour. Both models were subjected to the same loading and boundary conditions in a series of different non-linear analyses, including implicit, explicit, static and dynamic variants. The study shows that the two tested models differ greatly in terms of the obtained displacements, thus the sliding mechanism of muscle-fascia layers should not be ignored. As a side task, several finite element types were tested for proficiency in this particular computation.

  • Surface texture of pine wood beams after planing in industrial conditions
    • Michał Dobrzyński
    • Kazimierz Orłowski
    • Adam Boryczko
    2018 Annals of WULS, Forestry and Wood Technology

    Measuring the surface features of wooden components after planing is connected with the rising demands regarding to the quality of the painted window frames. In the paper the complex surface texture analysis especially identifying of surface damages using non-contact 3D measurement techniques for precise area measurement were presented.This enabled the study of irregular surface features with sufficient fidelity and resolution. Observed irregularities have diverse sizes and shapes and overlap in numerous layers.Executed in the paper exhaustive evaluation of various aspects of surface condition based on 3D surface texture parameters (ISO 25178) together with additional parameters were essential for defining irregular surface features. All those analysis are crucial for further industrial processes like painting and finally for quality of the entire product.

  • Surface Treatment of Rubber Waste
    • Xavier Colom
    • Marc Marín-Genescà
    • Krzysztof Formela
    • Javier Cañavate
    2018

    This chapter deals with the study of different approaches to improve the compatibility of waste rubber with polymeric matrixes of high density polyethylene (HDPE) by using surface treatments to increase adhesion. Different surface treatments such as etching with sulphuric and nitric acids, the use of a silane as a coupling agent and chlorination with trichloroisocyanuric acid (TCI) have been applied. The modification of waste rubber by grafting has also been studied. This process is based on the dynamical crosslinking of ethylene propylene diene monomer (EPDM) with peroxides. The mechanical properties of the resulting materials were studied and compared. The chemical modifications that occurred on the waste rubber were monitored by Fourier-transform infrared spectroscopy (FTIR). The behaviour of the materials at the fracture was assessed by means of scanning electron microscopy (SEM). The results of treated and untreated samples were compared with neat HDPE. Waste rubber, added to HDPE in small quantities, acts as a filler, improving the stiffness and providing a more brittle behaviour. Treatment with TCI gave poor mechanical properties obtaining lower values than neat HDPE in some cases, and in general worst properties than the other methods. The most interesting mechanical properties have been obtained by a grafting process based on EPDM dynamically crosslinked with a mixture of peroxides T-311 and dicumyl peroxide (DCP).

  • SURFACTANTS IN KLODNICA RIVER (KATOWICE, POLAND). PART II. QUATERNARY AMMONIUM COMPOUNDS
    • Marek Ruman
    • Ewa Olkowska
    • Żaneta Polkowska
    2018 Full text Ecological Chemistry and Engineering S - Chemia i Inżynieria Ekologiczna S

    The paper presents methods of determination of analytes of the cation group (alkyl benzyl dimethyl ammonium (BDDA-C12-C16), alkyl trimethyl ammonium (TMA), hexadecyl piridinium (HP)) in surface water and bottom sediment samples. In the sample preparation phase the solid phase extraction (SPE) or accelerated solvent extraction/ultrasound assisted extraction (ASE/UAE)-SPE technique was used and in the identification phase and quantitative determination of analytes phase - ion chromatography technique (combined with a conductivity detector (CD)). The determined concentrations were in the range below the determined method detection limit (MDL) or method quantification limit (MQL) figures up to 0.142 ±0.023 mg/dm3 or 2014 ±10 μg/kg (liquid and solid samples, respectively). Comparing concentrations of individual analytes found in liquid and solid environmental samples we may notice that surfactants containing a shorter alkyl chain in their molecules were found in higher concentrations in liquid samples (hydrophobicity increasing with the chain length).

  • Surrogate-assisted EM-driven miniaturization of wideband microwave couplers by means of co-simulation low-fidelity models
    • Piotr Kurgan
    • Slawomir Koziel
    2018 INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING

    This article proposes a methodology for rapid design optimization of miniaturized wideband couplers. More specifically, a class of circuits is considered, in which conventional transmission lines are replaced by their abbreviated counterparts referred to as slow-wave compact cells. Our focus is on explicit reduction of the structure size as well as on reducing the CPU cost of the design process. For the sake of computational feasibility, a surrogate-based optimization paradigm involving a co-simulation low-fidelity model is used. The latter is a fundamental component of the proposed technique. The low-fidelity model represents cascaded slow-wave cells replacing the low-impedance lines of the original coupler circuit. It is implemented in a circuit simulator (here, ADS) and consists of duplicated compact cell EM simulation data as well as circuit theory-based feeding line models. Our primary optimization routine is a trust-region-embedded gradient search algorithm. To further reduce the design cost, the system response Jacobian is estimated at the level of the low-fidelity model, which is sufficient due to good correlation between the low- and high-fidelity models. The coupler is explicitly optimized for size reduction, whereas electrical performance parameters are controlled using a penalty function approach. The presented methodology is demonstrated through the design of a 1-GHz wideband microstrip branch-line coupler. Numerical results are supported by experimental validation of the fabricated coupler prototype.

  • Sustainable urban planning in the context of studentification of the inner city areas
    • Joanna Badach
    2018

    The social dimension of urban planning as well as the importance of local communities and civic participation are often underlined in contemporary urban renewal and revitalisation programmes based on the principles of sustainable development. British Urban Renaissance is one the most far-reaching and widely discussed urban regeneration strategies which aims at repopulation and social diversification of inner city areas and land and building recycling. As a part of this programme some cities started to introduce at a large scale student accommodation in formerly vacant buildings. The phenomenon of student population growth, often referred to as studentification, can lead to significant transformation of urban structure and pose a serious threat to the sustainable development, especially in its spatial and social dimension. The aim of this article is to review some of the current research on studentification and to present initial observations in two cities – Bristol and Gdańsk where student population is significant in comparison to the number of city residents. The discussion will be followed by outlines for further research and urban analysis.

  • Svalbard reindeer as an indicator of ecosystem changes in the Arctic terrestrial ecosystem
    • Aneta Pacyna-Kuchta
    • Katarzyna Koziorowska
    • Stanisław Chmiel
    • Jan Mazerski
    • Żaneta Polkowska
    2018 Full text CHEMOSPHERE

    Over the years, noticeable effort has been directed towards contaminant determination in multiple biotic samples collected from the inhabitants of the Arctic. Little consideration has been given to polar herbivores, however, especially those from the European parts of the Arctic. To provide a broader perspective, we aimed to decipher trace element concentration in hairs of the key species in the Arctic, namely the Svalbard reindeer (Rangifer tarandus platyrhynchus), and to recognise whether diet variations could correspond with forward exposure. The effect of habitat and diet was investigated using the ratios of stable isotopes of carbon (δ13C) and nitrogen (δ15N), and previous literature studies on vegetation from the areas of interest. Analysis was performed for eighteen elements in total, both toxic and essential. Metals were present in a decreasing order Fe > Zn > Ba > Cu > Pb > Cr > Ni > V > Ga =La > Rb > As > Li > Co > Hg > Cd > Cs > Be. Similarity in trends in the studied subpopulations was observed for many metals. A significant log-linear correlation was observed for most of the elements, excluding nitrogen and carbon isotopes signature. Extremely high iron levels were determined in some of the samples, suggesting past iron overload. Zinc, in contrast to the remaining metals, did not correlate well with any other element. Mercury was determined at very low levels, in accordance with previous literature regarding its concentrations in moss and lichen species in Svalbard. The analysis of stable isotopes showed a high variation in nitrogen isotopes signatures. Further research is required to properly evaluate the potential health risks and ecological implications of elevated exposure.

  • Swoboda przepływu osób w krajach Unii Europejskiej - szanse i zagrożenia
    • Małgorzata Gawrycka
    • Jarosław Ziętarski
    • Marta Maier
    2018

    Celem niniejszego opracowania jest zbadanie, w jaki sposób swoboda przepływu osób wpłynęła na kształtowanie się salda populacji ludności i migracji w poszczególnych krajach UE. Autorzy mając na uwadze zachodzące przeobrażenia demograficzne zadali sobie pytanie w jaki sposób będą te zmiany wpływały na funkcjonowanie gospodarek oraz czy swoboda przepływu osób i migracje mogą rekompensować niedobory zasobów pracy wynikające ze zmian demograficznych? Na tej podstawie sformułowano następujące hipotezy badawcze: H1: Swoboda przepływu osób w państwach UE spowoduje w latach 2000-2015 odpływ netto, czyli utratę kapitału ludzkiego w niektórych państwach członkowskich. H2: Zaobserwowana w niektórych krajach UE utrata kapitału ludzkiego spowoduje osłabienie tempa wzrostu gospodarek narodowych. Na podstawie uzyskanych wyników dokonano kwalifikacji badanych krajów na tzw. państwa „typowo imigracyjne” oraz „typowo emigracyjne”. Migracje kapitału ludzkiego w badanym okresie odbywały się kosztem populacji niektórych państw UE. Mimo powstania państw typowo emigracyjnych nie zaobserwowano negatywnego wpływu emigracji netto na wielkość gospodarki tych państw na tle pozostałych państw UE. Główny kierunek migracji od gospodarek najmniejszych do tych największych jest logiczną konsekwencją występujących różnic bytowych. Migracja związana z lepszymi możliwościami dochodowymi i socjalnymi (poza emeryturami) – nazwana została przez autorów migracją pierwotną. Nazwana przez autorów publikacji wtórna fala migracyjna będzie następstwem uzyskania prawa do otrzymania świadczeń emerytalnych w jednych państwach i migracje do państw o niższych kosztach życia i/ lub chęci powrotu do swojego macierzystego kraju.

  • Symbiosis of Art and Technology – From Renaissance to Interactive Art,
    • Jan Buczkowski
    • Karolina Życzkowska
    2018

    The article presents the mutual relations between art and technology from the Renaissance to the interactive art of today. It indicates important factors influencing the possibilities of imaging and interpreting reality by artists, ranging from the development of oil painting techniques, linear perspective, the invention of printing and photography, to achievements related to the development of information technologies (computers, interfaces), offering a range of tools to create and co-create a work of art by the recipient.The subsequent stages of the symbiosis of these two seemingly distant domains of human activity are distinguished, along with examples of their practical realizations. In this way, four basic types of mutual inspirations of art and technology were pointed out - from one-sided relations (technology as an inspiration for art and vice versa), through two-way relations (the cooperation between an artist and an engineer in creating artistic works and technical solutions), up to and including the recipient in the process of creating an artwork, opening many new possibilities for interactive art. The paper shows that the co-existence of art and technology determines new possibilities for the creative work of both artists and engineers, also in the field of architecture. In the face of progressive digitization it gives a new dimension to art providing interactivity through various interfaces which can increase also the social dimensions of art.

  • Symmetrical and unsymmetrical diphosphanes with diversified alkyl, aryl and amino substituents
    • Natalia Szynkiewicz
    • Łukasz Ponikiewski
    • Rafał Grubba
    2018 Full text DALTON TRANSACTIONS

    We present the comprehensive study of diphosphanes with diversified substituents regarding their syntheses, structures, and properties. To this end, we have synthesized a series of novel unsymmetrical alkyl, aryl and amino-substituted diphosphanes of the general formula R1R2P-PR3R4 (where R1, R2, R3, R4 = tBu, Ph, Et2N or iPr2N) via salt metathesis reactionof halophosphanes with metal phosphides in high yield. We vastly expanded this group of compounds by obtaining the first mono- and tri-amino-substituted systems. The structures of isolated compounds were characterized by NMR spectroscopy and X-ray diffraction. The isolated unsymmetrical diphosphanes have no tendency to rearrange to corresponding symmetrical species. Additionally, we proposed the general classification of diphosphanes based on the number of different groups attached to phosphorus atoms and their distribution within a molecule. To investigate the impact of substituents on the properties of P-centers and a molecule as a whole we conducted a DFT study on electronic and steric properties of obtained systems. The experimental and theoretical results can be very useful for designing P-P systems with desired properties.

  • Symulacje numeryczne jako wsparcie badania właściwości barier ochronnych
    • Krzysztof Wilde
    • Dawid Bruski
    • Stanisław Burzyński
    • Jacek Chróścielewski
    • Łukasz Pachocki
    • Wojciech Witkowski
    2018 Full text Magazyn Autostrady

    Artykuł przedstawia możliwości wykorzystania symulacji numerycznych do badań efektywności urządzeń bezpieczeństwa ruchu drogowego w aspekcie sposobów ich konfgurowania. Obecnie w celu dopuszczenia do stosowania bariery ochronne muszą przejść specjalistyczne testy zderzeniowe. Ze względu na wysoki koszt tych badań coraz częściej producenci barier oraz inne podmioty odpowiadające za urządzenia bezpieczeństwa ruchu drogowego (brd) wspomagają się symulacjami komputerowymi. W artykule przedstawiono metodykę budowy modelu obliczeniowego do symulacji testu zderzeniowego wraz z kilkoma przykładami jego zastosowania. Wskazano również na istniejące prawne uwarunkowania wykorzystania symulacji numerycznych w procesie certyfkacji barier.

  • Symulacje numeryczne testów zderzeniowych barier ochronnych
    • Krzysztof Wilde
    • Dawid Bruski
    • Stanisław Burzyński
    • Jacek Chróścielewski
    • Łukasz Pachocki
    • Wojciech Witkowski
    2018 Full text Mosty

    W pracy przedstawiono metodykę budowy modelu obliczeniowego ukierunkowanego na badania zderzeniowe w środowisku Metody Elementów Skończonych. Opisano etapy tworzenia takiego modelu, jego modyfkacji oraz sprawdzania poprawności przeprowadzonej symulacji, a także przedstawiono kilka autorskich przykładów zastosowania proponowanych obliczeń do badania barier ochronnych

  • Synergistic Effects of Bitumen Plasticization and Microwave Treatment on Short-Term Devulcanization of Ground Tire Rubber
    • Łukasz Zedler
    • Marek Klein
    • Mohammad Saeb
    • Xavier Colom
    • Javier Cañavate
    • Krzysztof Formela
    2018 Full text Polymers

    Ground tire rubber (GTR) was mechano-chemically modified with road bitumen 160/220 and subsequently treated using a microwave radiation. The combined impact of bitumen 160/220 content and microwave treatment on short-term devulcanization of GTR was studied by thermal camera, wavelength dispersive X-ray fluorescence spectrometry (WD-XRF), static headspace, and gas chromatography-mass spectrometry (SHS-GC-MS), thermogravimetric analysis combined with Fourier transform infrared spectroscopy (TGA-FTIR), oscillating disc rheometer and static mechanical properties measurements. The obtained results showed that bitumen plasticizer prevents oxidation of GTR during microwave treatment and simultaneously improves processing and thermal stability of obtained reclaimed rubber.