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Publications from the year 2017
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GPU-Accelerated 3D Mesh Deformation for Optimization Based on the Finite Element Method
- Adam Lamęcki
- Adam Dziekoński
- Łukasz Balewski
- Grzegorz Fotyga
- Michał Mrozowski
This paper discusses a strategy for speeding up the mesh deformation process in the design-byoptimization of high-frequency components involving electromagnetic field simulations using the 3D finite element method (FEM). The mesh deformation is assumed to be described by a linear elasticity model of a rigid body; therefore, each time the shape of the device is changed, an auxiliary elasticity finite-element problem must be solved. In order to accomplish this in a very short time numerical integration and the solution of the resulting system of equations are performed using a graphics processing unit (GPU). The performance of the proposed algorithm is illustrated are verified using a complex example involving 3D FEM analysis of a dielectric-resonator filter
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GPU-Accelerated LOBPCG Method with Inexact Null-Space Filtering for Solving Generalized Eigenvalue Problems in Computational Electromagnetics Analysis with Higher-Order FEM
- Adam Dziekoński
- Michał Rewieński
- Piotr Sypek
- Adam Lamęcki
- Michał Mrozowski
This paper presents a GPU-accelerated implementation of the Locally Optimal Block Preconditioned Conjugate Gradient (LOBPCG) method with an inexact nullspace filtering approach to find eigenvalues in electromagnetics analysis with higherorder FEM. The performance of the proposed approach is verified using the Kepler (Tesla K40c) graphics accelerator, and is compared to the performance of the implementation based on functions from the Intel MKL on the Intel Xeon (E5-2680 v3, 12 threads) central processing unit (CPU) executed in parallel mode. Compared to the CPU reference implementation based on the Intel MKL functions, the proposed GPUbased LOBPCG method with inexact nullspace filtering allowed us to achieve up to 2.9-fold acceleration.
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Grabe J.:Recommendations of the "Committee for Waterfront Structures Harbours and Waterways" EAU 2012
- Zbigniew Cywiński
Recenzja - Grabe J.: Recommendations of the "Committee for Waterfront Structures Harbours and Waterways" EAU 2012. Ernst & Sohn, Berlin 2015
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Graphene field-effect transistor application for flow sensing
- Maciej Łuszczek
- Dariusz Świsulski
- Robert Hanus
- Marcin Zych
- Leszek Petryka
Microflow sensors offer great potential for applications in microfluidics and lab-on-a-chip systems. However, thermal-based sensors, which are commonly used in modern flow sensing technology, are mainly made of materials with positive temperature coefficients (PTC) and suffer from a self-heating effect and slow response time. Therefore, the design of novel devices and careful selection of materials are required to improve the overall flow sensor performance. In this work we propose graphene field-effect transistor (GFET) to be used as microflow sensor. Temperature distribution in graphene channel was simulated and the analysis of heat convection was performed to establish the relation between the fluidic flow velocity and the temperature gradient. It was shown that the negative temperature coefficient (NTC) of graphene could enable the self-protection of the device and should minimize sensing error from currentinduced heating. It was also argued that the planar design of the GFET sensor makes it suitable for the real application due to supposed mechanical stability of such a construction.
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Graphene Oxide as Mine of Knowledge: Using Graphene Oxide To Teach Undergraduate Students Core Chemistry and Nanotechnology Concepts
- Izabela Kondratowicz
- Kamila Sadowska
The aim of this laboratory experiment is to utilize graphene oxide (GO) material to introduce under-graduate students to many well-known concepts of general chemistry. GO is a new nanomaterial that has generated worldwide interest and can be easily produced in every well-equipped undergraduate chemical laboratory. An in-depth examination of GO synthesis, as well as a study of its structure and properties, allows students to familiarize themselves with the concepts of redox reactions, dispersity, and polarity, along with the basic concepts of spectroscopic methods. The inclusion of this carbonaceous nanomaterial within a basic chemistry curriculum can stimulate students’ interest and introduce them to the modern field of nanotechnology. Students are asked to prepare GO using the well-known improved Hummers’ method. Then they study the dispersion behavior of GO and carry out Fourier transform infrared and UV-vis spectroscopic measurements to characterize the material. The experiments are designed to be accomplished in five 3-h sessions and have been successfully incorporated into the second-year undergraduate course at Gdańsk University of Technology over a three-year period.
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Graphene oxide, reduced graphene oxide and composite thin films NO2 sensing properties
- Katarzyna Dunst
- Błażej Scheibe
- Grzegorz Nowaczyk
- Stefan Jurga
- Piotr Jasiński
A graphene oxide (GO), reduced graphene oxide (RGO) and poly(3,4-ethylenedioxytiophene)- reduced graphene oxide (PEDOT-RGO composite) gas sensors were successfully fabricated using an electrodeposition method. The electrodeposition was carried out in aqueous GO dispersions. In order to obtain RGO and PEDOT-RGO, the electrochemical reduction of GO and PEDOT-GO was carried out in 0.1 M KCl at constant potential of −0.85 V. The GO, RGO and PEDOT-RGO composites were characterized by scanning and high resolution transmission electron microscopies with electron energy loss spectroscopy, Fourier-transform infrared and Raman spectroscopies. In this work the effect of GO electrochemical reduction process was discussed. The effects of the humidity and sensing response of GO, RGO and PEDOT-RGO to different gases were investigated. It was found out the PEDOT-RGO response to NO2 was much higher than to the other analyzed gases. The influence of the operating temperature on the gas sensing response was compared. The role of the polymer and RGO in PEDOT-RGO composite has been indicated. The results are discussed in light of recent literature on graphene sensors.
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Green Sample Collection
- Mariusz Marć
- Monika Śmiełowska
- Bożena Zabiegała
The term of “green sample collection” is directly associated with both passive and dynamic analytical tools which allow for simultaneous management of the stage of collection and isolation and/or enrichment of a broad spectrum of chemical compounds from environmental samples. The use of passive sampling techniques at the stage of sample collection makes it possible to obtain in a simple yet inexpensive manner an analytical information on time weighted average concentration of chemical compounds in environmental samples, without any support of high-tech equipment. However, the use of dynamic techniques at the stage of sampling analytes from environmental matrix allows for obtaining a very high degree of enrichment and for collection onto a sorption medium of a considerable number of chemical compounds in the course of a single sampling process. This chapter provides information on the practical use of passive and dynamic techniques in the environmental analytics (air, water, soil). The following two basic aspects of making use of these techniques will be discussed in the context of the philosophy of green analytical chemistry: (1) the stage of analyte sampling from environmental matrix and (2) the stage of analyte desorption in laboratory conditions.
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Greener organic solvents in analytical chemistry
- Marek Tobiszewski
- Jacek Namieśnik
The paper presents the most recent advances in analytical applications of greener organic solvents. Substitution of problematic solvents with more benign organic ones is much easier than shifting to technique applying alternative solvents, such as ionic liquids or supercritical fluids. In the area of liquid chromatography greener mobile phases, much attention is given to application ethanol or acetone instead of acetonitrile. Solvent-based extractions more often include the application of bio-based organic solvents, such as esters, alcohols or terpenes. All solvents applied in analytical sciences should be carefully assessed before their application.
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Growing role of walking and cycling and the associated risks
- Romanika Okraszewska
- Krystian Birr
- Lucyna Gumińska
- Lech Michalski
Increasing the role of active mobility, including walking and cycling, is one of the tools for developing sustainable urban transport systems as recommended by the EU. The article describes the trends in pedestrian and bicycle traffic in Poland and its share in urban modal split. It identifies and describes the main sources of risks to pedestrian and cycle safety. Recommendations are proposed on how to ensure that pedestrians and cyclists can use traffic safely.
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Growth, Crystal Structure and Magnetic Characterization of Zn-Stabilized CePtIn4
- Elizabeth M. Carnicom
- Tomasz Klimczuk
- Fabian von Rohr
- Michał Jerzy Winiarski
- Tai Kong
- Karoline Stolze
- Weiwei Xie
- Satya Kushwaha
- Robert J. Cava
The growth and characterization of CePtIn4, stabilized by 10% Zn substitution for In, is reported. The new material is orthorhombic, space group Cmcm (No. 63), with lattice parameters a = 4.51751(4) Å, b = 16.7570(2) Å, and c = 7.36682(8) Å, and the refined crystal composition has 10% of Zn substituted for In, i.e., the crystals are CePt(In0.9Zn0.1)4. Crystals were grown using a self-flux method: only growths containing Zn yielded CePtIn4 crystals, while Ce3Pt4In13 crystals formed when Zn was not present. Anisotropic temperature-dependent magnetic susceptibilities for single crystals show that Zn-stabilized CePtIn4 orders magnetically at ∼1.9 K. High-temperature Curie–Weiss fits indicate an effective moment of ∼2.49 μB/Ce and a directionally averaged Weiss-temperature of approximately −31 K. Specific heat data shows a peak consistent with the ordering temperature seen in the magnetic susceptibility data. Zn-stabilized CePtIn4 is metallic and displays no superconducting transition down to 0.14 K.
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Growth Orientation of Women and Men Owners of Micro Firms in the Pomerianian Region
- Julita Wasilczuk
Despite the fact that research on women’s entrepreneurship has been conducted for many years, still many clear answers to questions about the differences between entrepreneurs of both genders are missing. One of the unresolved issues is the performance of women in entrepreneurship. The aim of the study is to investigate the growth orientation of microenterprises operating in the Pomeranian region in Poland and to compare its level according to the gender of the owner. An index of entrepreneurs’ growth orientation was developed. This index, being a determinant of the company’s growth potential, was based on five indicators: goals and plans of the entrepreneur, innovative activities, investment, and activity in finding sources of funding. The data was gathered by a face to face survey, based on a questionnaire, among microfirm owners from the Pomeranian region – Poland, in 2009 and 2012. The analysis of growth orientation of women and men, pointed out that the first showed a lower indicator of it, however again the general conclusions are not so clear.
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Grupa gdańskich topologów
- Zdzisław Dzedzej
Artykuł o charakterze przeglądowym. Jako rozdział 6 w książce zawiera przegląd najważniejszych rezultatów badawczych uzyskanych przez dużą grupę matematyków związanych z Uniwersytetem i Politechniką Gdańską określanych potocznie grupą topologów, a także uwagi historyczne dotyczące rozwoju tych zespołów. Dołączono i pokrótce omówiono obszerną bibliografię.
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Guided wave propagation for assessment of adhesive bonding between steel and concrete
- Beata Zima
- Magdalena Rucka
Adhesive bonding is becoming more increasingly important in joining of structural elements. In civil engineering, there is a growing interest in connection by adhesive bonding in steel-concrete flexural members. This study concerns the guided wave propagation technique applied to condition assessment of an adhesive connection between a steel member and a concrete beam. Various states of degradation were considered by producing several laboratory samples differing in the placement and the length of the adhesive bond. Piezoelectric transducers were used to excite and to register signals of propagating waves. In addition, the finite elements method was used to simulate propagation of guided waves at the bond-line between steel and concrete. Results for the beam with perfect bonding were compared with results obtained for beams with partially degraded connections. The influence of the length of damaged bond and its position on registered signals was investigated.
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Gustav Oelsner i Hugo Althoff. W poszukiwaniu godnych warunków zamieszkania w Altonie i Gdańsku
- Małgorzata Kostrzewska
Celem artykułu jest porównanie aktywności zawodowej dwóch architektów miejskich odpowiedzialnych za przestrzenny i architektoniczny rozwój Gdańska i Altony - Hugona Althoffa i Gustava Oelsnera, oraz porównanie architektury i urbanistyki modernistycznych osiedli socjalnych. Celem porównania jest zbadanie, w jakim stopniu lokalne uwarunkowania i tradycja mogą być nośnikiem uniwersalnych ideałów modernizmu i indywidualnej ekspresji architekta. Artykuł zwraca także uwagę na społeczną rolę i wrażliwość na potrzeby człowieka architektów okresu modernizmu. Cechy te wydają się być obecnie zapomniane, ale ich przywołanie wydaje się istotne w kontekście współczesnej dyskusji nad warunkami życia w mieście.
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Haemocompatibility of Modified Nanodiamonds
- Michał Wąsowicz
- Mateusz Ficek
- Maciej Wróbel
- Ruchira Chakraborty
- Dror Fixler
- Paweł Wierzba
- Małgorzata Szczerska
This study reports the interactions of modified nanodiamond particles in vitro with human blood. Modifications performed on the nanodiamond particles include oxygenation with a chemical method and hydrogenation upon chemical vapor deposition (CVD) plasma treatment. Such nanodiamonds were later incubated in whole human blood for different time intervals, ranging from 5 min to 5 h. The morphology of red blood cells was assessed along with spectral measurements and determination of haemolysis. The results showed that no more than 3% of cells were affected by the nanodiamonds. Specific modifications of the nanodiamonds give us the possibility to obtain nanoparticles which are biocompatible with human blood. They can form a basis for the development of nanoscale biomarkers and parts of sensing systems and devices useful in biomedical environments.
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Hale systemowe GALBOX wykonane całkowicie z kształtowników giętych na zimno
- Mateusz Sondej
W artykule przedstawiono hale systemowe Galbox, wykonane z profili giętych na zimno. Zaprezentowano zależność ciężaru hal stalowych dla różnych rozwiązań konstrukcyjnych.
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Handwritten signature verification system employing wireless biometric pen
- Michał Lech
- Andrzej Czyżewski
The handwritten signature verification system being a part of the developed multimodal biometric banking stand is presented. The hardware component of the solution is described with a focus on the signature acquisition and on verification procedures. The signature is acquired employing an accelerometer and a gyroscope built-in the biometric pen plus pressure sensors for the assessment of the proper pen grip and then the signature verification method based on adapted Dynamic Time Warping (DTW) method is applied. Hitherto achieved FRR and FAR measures for the verification based exlusively on the biometric pen sensors and for the comparison on the parameters retrieved from the signature scanning pad are compared.
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Harmonics produced by traction substations – computer modelling and experimental verification
- Robert Kowalak
- Stanisław Czapp
- Krzysztof Dobrzyński
- Jacek Klucznik
- Zbigniew Lubośny
Voltage and current harmonics have a detrimental effect on the components of a power system. Current harmonics may result in the overload and damage to power transformers. Voltage harmonics may result in, for example, damage to capacitor banks used to compensate reactive power. Devices which contribute to both current and voltage distortion include traction rectifiers. This paper presents results of the computer investigation of the effect of these rectifiers on the power supply network. The results of the computer investigation have been compared with the result of experimental study.
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Heat treatment effect on Eu3+ doped TeO2-BaO-Bi2O3 glass systems with Ag nanoparticles.
- Tomasz Lewandowski
- Michał Dembski
- Michalina Walas
- Marcin Stanisław Łapiński
- Magdalena Narajczyk
- Wojciech Sadowski
- Barbara Kościelska
Glass systems of 73TeO2-4BaO-3Bi2O3-2Eu2O3-xAg ( in molar ratio where x= 0, 1, 2, 3) compositions have been successfully synthesized. Silver nanoparticles were obtained with the employment of heat treatment (HT) procedure executed at 350 °C. Glass transition temperatures of different compositions have been determined through DSC measurements. XRD measurement results presented characteristic amorphous halo indicating lack of long range order in the samples. FTIR structural studies reveled that glass matrix is mainly composed of TeO3 and TeO4 species and is stable after different applied heat treatment times. X-ray photoelectron spectroscopy measurements (XPS) confirmed that in selected samples part of Ag ions changed oxidation state to form Ag0 species. TEM measurements revealed nanoparticles of size in the range of 20-40 nm. UV-vis absorption results demonstrated characteristic transitions of Eu3+ ions. Additionally, UV-vis spectra of samples heat treated for 2 6, 12, 24 and 48 hours presented bands related to silver nanoparticles. Photoluminescence studies (PL) have been performed with excitation wavelength of λexc=395 nm. Obtained spectra exhibited peaks due to 5D0-7FJ (where J= 2,3,4) and 5D1-7FJ (where J= 1,2,3) transitions of Eu3+. Moreover, luminescence measurement indicated enhancement of rare earth ions emissions in several of the annealed samples. Increase of emission intensity of about 35% has been observed.