2021 - Repozytorium publikacji - Politechnika Gdańska

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Sounding rocket vibration mechanical filter and amplifier
- Adam Dąbrowski
- Szymon Krawczuk
- Jacek Goczkowski
- Karol Pelzner
2021 Pełny tekst
Measuring accelerations and vibrations of a sounding rocket provides both information for engineers on the launcher vehicle performance as well as environment description for future payload designers. Typically, information on the level of vibration and eigenfrequencies are required to properly design a payload. This paper presents a design of a novel mechanical filter and amplifier for mechanical vibrations. Its key feature is the possibility to tune to a specific frequency so that it acts as a bandpass filter. Its application enables widening the sensing range of a vibration sensor, such as an accelerometer, a strain gauge or a contactless sensor. The device has been successfully validated on a small sounding rocket and provided detailed description of the rocket’s dynamic behaviour. Conclusions from the flight campaign as well as possibilities for other applications are discussed. Application of the sensor can result in better insight into the launch vehicle dynamics, thus resulting in the improvement of overall sounding rocket performance.
Sources and composition of chemical pollution in Maritime Antarctica (King George Island), part 2: Organic and inorganic chemicals in snow cover at the Warszawa Icefield
- Danuta Szumińska
- Joanna Potapowicz
- Małgorzata Szopińska
- Czapiewski Sebastian
- Ulrike Falk
- Marcin Frankowski
- Żaneta Polkowska
2021 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT
The study area is located on King George Island, where 90% of the area is permanently glaciated. This study provides a comprehensive analysis of the inorganic and organic chemistry of snow cover in the icefield and a comparison against previous results obtained in fresh water. Snow samples were collected in the summer of 2017 in the Warszawa Icefield area. Sampling points are located along two transects: between the Arctowski Polish Polar Station and the Carlini Base (N = 4), and from the forefield to the upper part of Ecology Glacier (N = 5). In the snow samples, (1) basic ions, (2) major trace metals and metalloids (and B), and (3) polycyclic aromatic hydrocarbons (PAHs) were detected and quantified. Additionally, the parameters of pH, specific electrolytic conductivity (SEC25) and total organic carbon (TOC) were determined. The results show a low concentration of inorganic elements (<30 mg/L), TOC (<1 mg/L) and PAHs (0.11–1.4 ng/L) in collected snow samples. A slight increase in PAHs and heavy-metals concentration has been observed at the marginal parts of the icefield, which suggests the impact of scientific stations. Based on this result there is a need to conduct research on pollutant levels in ice cores on King George Island to assess the risk associated with rapid glacier thawing and pollution remobilisation.
Space and spatial practices in times of confinement. Evidence from three European countries: Austria, France and Poland
- Izabela Mironowicz
- Stefan Netsch
- Anna Geppert
2021 Urban Design International
In the first half of 2020, millions of people were subjected to drastic restrictions aimed at limiting the spread of the Covid-19 disease. Austria, France and Poland have implemented a lockdown to varying degrees and for varying lengths of time. This is an unprecedented situation in Europe: until now, even in times of war, curfew measures have never been applied 24 h a day. The research presented in this article was carried out in real time, in April and May 2020, with the help of urban planning students from three countries. Its objective is to observe the interaction between these measures and the urban space in two dimensions. On the one hand, we analyse the impact of these measures on the urban space and on the spatial practices of the inhabitants. On the other hand, we examine the conditions which different types of urban and rural space have provided for the inhabitants experiencing confinement. This empirical study leads to a discussion and recommendation for the town planners of the future.
Spatial differentiation of road safety in Europe based on NUTS-2 regions
- Joanna Wachnicka
- Katarzyna Palikowska
- Wojciech Kustra
- Kieć Mariusz
2021 Pełny tekst ACCIDENT ANALYSIS AND PREVENTION
Road safety varies significantly across the regions in Europe. To understand the factors behind this differentiation and the effects they have, data covering 263 NUTS-2 (Nomenclature of Territorial Units for Statistics) regions across Europe (European Union and Norway) have been analysed. The assessment was made using Geographically Weighted Regression (GWR). As a dependent variable the Road Fatality Rate (RFR – number of fatalities in a given year per one million population of the region) was used. The GWR was developed from 2014 data and took account of variables that characterise economic, infrastructural and social development. The model was validated using 2016–2018 data. The following factors were found to be statistically significant: gross domestic product per person (GDPPC), number of passenger cars per inhabitant (MRPC), share of passenger vehicles (PPC), life expectancy at birth (LIFE), as well as variables related to the border of the regions, innerborder (IB) and outerborder (OB). Results suggest that the GWR has an advantage over the global linear model which does not address regional proximity. The model allows for identification of the differences in the level of road safety in regions, estimated on the basis of the RFR and the available data in Eurostat databases. This in turn allows for indicating regions in which activities to improve road safety should have the highest priority. The model shows a large spatial diversity of factors affecting the RFR, which indicates the need to take different actions to improve road safety depending on the region. The results suggest that the GWR model can be useful for predicting and more efficient management of road safety at the regional level in Europe.
Spatial Modelling in Environmental Analysis and Civil Engineering
- Artur Janowski
- Jakub Szulwic
- Paweł Tysiąc
2021 Pełny tekst Applied Sciences-Basel
As can be seen, Spatial Modelling in Environmental Analysis and Civil Engineering applies to a multitude of applications. In an attempt to bring the topic closer to potential readers, the special issue referred to security methods, optimization of calculations, conducting measurements and empirical tests. Each article has made an original contribution to the development of practical science that can be replicated by researchers around the world. Being aware of the multitude of technological solutions and possible applications, we want to promote this type of research.
Spawanie ramy motocyklowej ze stopu aluminium metodami TIG i MIG
- Dariusz Fydrych
- Anna Janeczek
- Sławomir Bania
2021 Pełny tekst Przegląd Spawalnictwa
Naprawa uszkodzonych elementów konstrukcji technologiami spawalniczymi może pozwolić na przedłużenie ich eksploatacji przy stosunkowo niskich kosztach i krótkim czasie wyłączenia z użytkowania. W pracy porównano cztery technologie spawania ramy motocyklowej Kawasaki wykonanej ze stopu aluminium PA11 (AW 5754, Wr. nr. 3.3535, AlMg3). Spawanie przeprowadzono procesami TIG oraz MIG z wykorzystaniem materiałów dodatkowych AlSi5, AlMg5Mn i AlMg5Cr. Złącza zostały poddane wstępnym badaniom: wizualnym oraz badaniom niszczącym - statycznej próbie rozciągania i pomiarom twardości metodą Vickersa. Stwierdzono, że obydwie metody spawania są możliwym do zastosowania sposobem naprawy ramy, a materiały dodatkowe zawierające Mg pozwalają uzyskać złącze spawane o wytrzymałości na rozciąganie około 10 MPa wyższej, niż spoiwo AlSi5. Twardość spoiny wykonanej z użyciem materiału dodatkowego AlSi5 była wyższa o 14 do 22 HV10 niż twardość spoin wykonanych ze spoiwami AlMg5Mn i AlMg5Cr.
Special Issue "Applications of Finite Element Modeling for Mechanical and Mechatronic Systems"
- Marek Krawczuk
- Magadalena Palacz
2021 Pełny tekst Applied Sciences-Basel
Numerical modeling is very important in today's engineering because, among other things, it reduces the costs associated with prototyping or predicting the occurrence of potentially dangerous situations during operation in certain defined conditions. Different methods have so far been used to implement the real structure into the numerical version. The most popular have been variations of the finite element method (FEM). The aim of the proposed Special Issue is to familiarize the reader with the latest applications of the finite element method for the modeling and analysis of diverse mechanical problems.
Spectacular Oxygen Evolution Reaction Enhancement through Laser Processing of the Nickel‐Decorated Titania Nanotubes
- Jakub Wawrzyniak
- Jakub Karczewski
- Emerson Coy
- Igor Iatsunskyi
- Jacek Ryl
- Maria Gazda
- Katarzyna Grochowska
- Siuzdak Katarzyna
2021 Advanced Materials Interfaces
The selective, laser‐induced modification of the nickel‐decorated titania nanotubes provides remarkable enhancement toward oxygen evolution reaction. Particularly, the irradiation of the laterally spaced crystalline TiO2 nanotubes, results in the formation of the tight closure over irradiated end, preserving their hollow interior. The shape of the absorbance spectra is modulated along with applied energy, and the new absorption band appears at 500 nm, where the local minimum can be found for bare nanotubes. The high‐resolution X‐ray photoelectron spectra indicate the presence of both metallic and hydroxide forms of nickel species. The electrode material treated with 355 nm pulses at 50 mJ cm−2 shows significantly improved current densities in the anodic regime, reaching nearly 300 mA cm−2 while exposed to solar radiation, whereas the untreated sample barely comes to 1.5 mA cm−2 in the same conditions. The tailored titania photoanode also exhibits two orders of magnitude higher donor concentration in comparison to the primary substrate as verified by Mott–Schottky analysis. The electrochemical analysis confirms the key role of laser annealing in enhancing the effectiveness of light‐driven water splitting
Spectacular Oxygen Evolution Reaction Enhancement Through Laser Processing of the Nickel-Decorated Titania Nanotubes
- Jakub Wawrzyniak
- Jakub Karczewski
- Emerson Coy
- Igor Iatsunskyi
- Jacek Ryl
- Maria Gazda
- Katarzyna Grochowska
- Siuzdak Katarzyna
2021 Pełny tekst Advanced Materials Interfaces
The selective, laser-induced modification of the nickel-decorated titania nanotubes provides remarkable enhancement toward oxygen evolution reaction. Particularly, the irradiation of the laterally spaced crystalline TiO2 nanotubes, results in the formation of the tight closure over irradiated end, preserving their hollow interior. The shape of the absorbance spectra is modulated along with applied energy, and the new absorption band appears at 500 nm, where the local minimum can be found for bare nanotubes. The high-resolution X-ray photoelectron spectra indicate the presence of both metallic and hydroxide forms of nickel species. The electrode material treated with 355 nm pulses at 50 mJ cm−2 shows significantly improved current densities in the anodic regime, reaching nearly 300 mA cm−2 while exposed to solar radiation, whereas the untreated sample barely comes to 1.5 mA cm−2 in the same conditions. The tailored titania photoanode also exhibits two orders of magnitude higher donor concentration in comparison to the primary substrate as verified by Mott–Schottky analysis. The electrochemical analysis confirms the key role of laser annealing in enhancing the effectiveness of light-driven water splitting.
SPECTRAL RESPONSE OF STATIONARY JACK-UP PLATFORMS LOADED BY SEA WAVES AND WIND USING PERTURBATION METHOD
- Bogdan Rozmarynowski
- Wojciech Jesien
2021 Pełny tekst Polish Maritime Research
The paper addresses non-linear vibrations of offshore jack-up drilling platforms loaded by sea waves and wind in their stationary condition using the perturbation method. Non-linearity of dynamic equations of motion for fixed offshore platforms yields from two factors. The first is load excitation generating non-linear velocity coupling in a dynamic system. This coupling is inherent in the modified Morison equation, involving the excitation function in the form of the sum of the inertial and velocity forces of sea waves, taking into account relative wave–structure kinematics. Moreover, the wind acting on the exciting side causes similar effects. The second source is the subsoil‒structure interaction problem, modelled by a system of springs and dashpots that yields stochastic non-linearity of the dynamic system. The matrix equations of structural motion in FEM terms are set up. The perturbation method is adopted to determine the mechanical response of the system, making it possible to determine response spectra of the first and the second approximations for displacements and internal forces of the platform. The paper is the continuation of research detailed in the paper [1]. It is assumed, that the fluctuation parts of the dynamic loading forces are in line with the direction of sea wave propagation. Sea current and lift forces effects are neglected in this study. A numerical example refers to structural data of the Baltic drilling platform in the stationary configuration, i.e. when three legs support the deck above the seawater level.
Speed observer of induction machine based on backstepping and sliding mode for low‐speed operation
- Marcin Morawiec
- Arkadiusz Lewicki
- Filip Wilczyński
2021 Pełny tekst ASIAN JOURNAL OF CONTROL
This paper presents a speed observer design based on backstepping and slidingmode approaches. The inputs to the observer are the stator current and thevoltage vector components. This observer structure is extended to the integra-tors. The observer stabilizing functions contain the appropriate sliding surfaceswhich result from the Lyapunov function. The rotor angular speed is obtainedfrom the non‐adaptive formula with a sliding mode mechanism. It allowsimprovement of the robustness of parameters uncertainties and the zero rotorspeed to work (near to the unobservable region). In the sensorless controlsystem, the classical first‐order sliding‐mode controllers are applied with thetransformation of the multi‐scalar variable. The proposed control system struc-ture can be named full‐decoupled due to multi‐scalar variables transformationand the feedback control law obtained from the Lyapunov theorem. The theo-retical derivations are verified in experimental waveforms. The sensorlesscontrol system's robustness is verified in the experimental investigations byusing the nominal machine parameters uncertainties method.
Speed Observer Structure of Induction Machine Based on Sliding Super-Twisting and Backstepping Techniques
- Marcin Morawiec
- Arkadiusz Lewicki
2021 Pełny tekst IEEE Transactions on Industrial Informatics
This paper presents an analysis of the two speed observer structures which are based on the backstepping and sliding super twisting approach. The observer stabilizing functions result from the Lyapunov theorem. To obtain the observer tuning gains the observer structure is linearized near the equilibrium point. The rotor angular speed is obtained from non-adaptive dependence. In the sensorless control system structure the classical PI controllers and transformation to the multi-scalar variables are applied. The theoretical derivations are verified in experimental waveforms. Comparison of both speed observer structures is presented for nominal speed, load torque injections while regenerating mode, very low speed range and the uncertainties of nominal parameters of induction machine.
Spin and Orbital Effects on Asymmetric Exchange Interaction in Polar Magnets: M(IO3)2 (M = Cu and Mn)
- Ebube E. Oyeka
- Michał Winiarski
- Maurice Sorolla II
- Keith M. Taddei
- Allen Scheie
- Thao Tran
2021 INORGANIC CHEMISTRY
Magnetic polar materials feature an astonishing range of physical properties, such as magnetoelectric coupling, chiral spin textures, and related new spin topology physics. This is primarily attributable to their lack of space inversion symmetry in conjunction with unpaired electrons, potentially facilitating an asymmetric Dzyaloshinskii–Moriya (DM) exchange interaction supported by spin–orbital and electron–lattice coupling. However, engineering the appropriate ensemble of coupled degrees of freedom necessary for enhanced DM exchange has remained elusive for polar magnets. Here, we study how spin and orbital components influence the capability of promoting the magnetic interaction by studying two magnetic polar materials, α-Cu(IO3)2 (2D) and Mn(IO3)2 (6S), and connecting their electronic and magnetic properties with their structures. The chemically controlled low-temperature synthesis of these complexes resulted in pure polycrystalline samples, providing a viable pathway to prepare bulk forms of transition-metal iodates. Rietveld refinements of the powder synchrotron X-ray diffraction data reveal that these materials exhibit different crystal structures but crystallize in the same polar and chiral P21 space group, giving rise to an electric polarization along the b-axis direction. The presence and absence of an evident phase transition to a possible topologically distinct state observed in α-Cu(IO3)2 and Mn(IO3)2, respectively, imply the important role of spin–orbit coupling. Neutron diffraction experiments reveal helpful insights into the magnetic ground state of these materials. While the long-wavelength incommensurability of α-Cu(IO3)2 is in harmony with sizable asymmetric DM interaction and low dimensionality of the electronic structure, the commensurate stripe AFM ground state of Mn(IO3)2 is attributed to negligible DM exchange and isotropic orbital overlapping. The work demonstrates connections between combined spin and orbital effects, magnetic coupling dimensionality, and DM exchange, providing a worthwhile approach for tuning asymmetric interaction, which promotes evolution of topologically distinct spin phases.
Spontaneous electron emission vs dissociation in internally hot silver dimer anions
- Patryk Jasik
- Jan Franz
- Dariusz Kędziera
- Tymon Kilich
- Jan Kozicki
- Józef Eugeniusz Sienkiewicz
2021 Pełny tekst JOURNAL OF CHEMICAL PHYSICS
Referring to a recent experiment, we theoretically study the process of a two-channel decay of the diatomic silver anion (Ag2-), namely the spontaneous electron ejection giving Ag2 + e- and the dissociation leading to Ag- + Ag. The ground state potential energy curves of the silver molecules of diatomic neutral and negative ion were calculated using proper pseudo-potentials and atomic basis sets. We also estimated the non-adiabatic electronic coupling between the ground state of Ag2- and the ground state of Ag2 + e-, which in turn allowed us to estimate the minimal and mean values of the electron autodetachment lifetimes. The relative energies of the rovibrational levels allow the description of the spontaneous electron emission process, while the description of the rotational dissociation is treated with the quantum dynamics method as well as time-independent methods. The results of our calculations are verified by comparison with experimental data.
Sprzętowa implementacja transformacji Hougha w czasie rzeczywistym
- Paweł Kowalski
- Robert Smyk
2021 Pełny tekst Poznan University of Technology Academic Journals. Electrical Engineering
W artykule przedstawiono implementację sprzętową w FPGA algorytmu do wykrywania kształtów aproksymowanych zbiorem linii prostych podczas przetwarzania obrazu cyfrowego w czasie rzeczywistym. W opracowanej strukturze sprzętowej podniesiono efektywność przetwarzania poprzez zastosowanie przetwarzania przepływowego, lookup table, wykorzystanie wyłącznie arytmetyki liczb całkowitych oraz rozproszenie pamięci głosowania. Eksperymentalnie wykorzystano przedstawioną strukturę w torze przetwarzania obrazu w czasie rzeczywistym złożonym z kamery OV7670, płyty deweloperskiej Terasic DE10-nano oraz monitora podłączonego za pomocą HDMI. Pełny tor przetwarzania został zaimplementowany w pojedynczym układzie FPGA Intel Cyclone V. Maksymalna prędkość przetwarzania obrazu z wykorzystaniem opracowanej implementacji została określona na 275 MHz.
SrCe0.9In0.1O3-δ-based reversible symmetrical Protonic Ceramic Cell
- Wojciech Skubida
- Kun Zheng
- Anna Stępień
- Konrad Świerczek
- Alicja Klimkowicz
2021 MATERIALS RESEARCH BULLETIN
In-doped SrCe0.9In0.1O3-δ (SCI) perovskite-type oxide is utilized as the solid electrolyte, as well as a component, together with SrFe0.75Mo0.25O3-δ (SFM) compound, in the composite-type electrodes to construct symmetrical Protonic Ceramic Fuel Cells (PCFC). With good mutual stability of SCI and SFM at high temperatures in water vapor-containing reducing and oxidizing conditions, as well as sufficient ionic conductivity with high proton transference number of SrCe0.9In0.1O3-δ, and high electronic conduction of SrFe0.75Mo0.25O3-δ, effectiveness of the electrochemical reactions is ensured. It is documented that 80:20 wt.% SFM-SCI electrode performs better, comparing to the one having 50:50 wt.% ratio of both compounds, with both electrodes showing lower polarization resistance values in the reducing conditions. Symmetrical SCI-SFM|SCI|SCI-SFM cells can be operated in normal (PCFC) and reversed, Protonic Ceramic Electrolyzer Cell (PCEC) mode, showing similar shape of current density-voltage characteristics. The maximum obtained power density is 32 mW cm−2 at 800 °C.
S-scheme heterojunction Bi2O3-ZnO/Bentonite clay composite with enhanced photocatalytic performance
- V. Landge
- S.h. Sonawane
- M. Sivakumar
- S.s. Sonawane
- G. U. Babu
- Grzegorz Boczkaj
2021 Sustainable Energy Technologies and Assessments
The industrial waste water is always a bottleneck problem in the modern civilization of the present era. In a quest to develop effective methods for the elimination of lethal pollutants from the waste water and water remediation, this work is focused on the development of a rapid and proficient approach for preparing supported binary metal oxide catalyst for photocatalytic advance oxidation process used in waste water treatment applications. The sonochemical synthesis of novel S-scheme Bi2O3-ZnO supported on bentonite clay nanocomposite is demonstrated for the photocatalytic oxidation of Congo red (CR). The effectiveness of catalyst to degrade CR dye was determined using UV–visible spectroscopy under different experimental conditions such as catalyst loading, time of UV exposure and concentration of H2O2. The synthesized catalyst demonstrated excellent photocatalytic oxidation under UV light. The pseudo-first-order rate constant obtained for this reaction was 0.029 min−1. Nearly total degradation of CR dye was achieved in 1 h under UV light irradiation using the catalyst. This remarkable increase in the catalytic performance of Bi2O3-ZnO/bentonite clay is due to the S-scheme mechanism of charge transfer between ZnO and Bi2O3, through enhanced redox potential. Also, its efficient recoverability and reusability (5 times) establish its promising potential for catalytic applications.
Stability Analysis of Shunt Active Power Filter with Predictive Closed-Loop Control of Supply Current
- Agata Bielecka
- Daniel Wojciechowski
2021 Pełny tekst ENERGIES
This paper presents a shunt active power filter connected to the grid via an LCL coupling circuit with implemented closed‐loop control. The proposed control system allows selective harmonic currents compensation up to the 50th harmonic with the utilization of a model‐based predictive current controller. As the system is fully predictive, it provides high effectiveness of the harmonic reduction, which is proved by waveforms achieved in performed tests. On the other hand, the control system is prone to loss of stability. Therefore, the paper is focused on the stability analysis of the discussed control system with the additional outer control loop of the supply current with predictive control of this current. The conducted stability analysis encompasses the assessment of system stability as a function of the coupling circuit parameter identification accuracy, whose values are implemented in the current controller, as well as parameters such as the sampling frequency and proportional–integral (PI) controller coefficients. The obtained results show that the ranges of the LCL circuit parameter identification accuracy for which the system remains stable are relatively wide. However, the most effective compensation of the supply current distortion is achieved for the parameters identified correctly, and the greatest impact on the compensation quality has the value of L1 inductance.
Stability analysis of single-walled carbon nanotubes embedded in winkler foundation placed in a thermal environment considering the surface effect using a new refined beam theory
- Jena Subrat Kumar
- S. Chakraverty
- Mohammad Malikan
- Francesco Tornabene
2021 Pełny tekst MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
This article is devoted to investigate the stability of different types of Single Walled Carbon Nanotubes (SWCNTs) such as zigzag, chiral, and armchair types which are rested in Winkler elastic foundations exposing to both the low and high temperature environments. Also, the Surface effects which include surface energy and surface residual stresses, are taken into consideration in this study. It may be noted that the surface energy aids in the increase of the flexural rigidity whereas the surface residual stresses act as distributed transverse load. Further, the proposed model is developed by considering a novel refined beam theory namely one variable first order shear deformation beam theory along with the Hamilton’s principle. Navier’s method has been implemented to find out the critical buckling loads for Hinged-Hinged (H-H) boundary condition for zigzag, chiral, and armchair types of SWCNTs. A parametric study is also conducted to report the influence of various scaling parameters like small scale parameters, change in temperature, Winkler stiffness, and length to diameter ratio on critical buckling loads. Also, the present model is validated by comparing the results with other published work.
Stability and phase transition investigation of olanzapine polymorphs
- Jiequn Tang
- Yanqiang Han
- Imran Ali
- Hongyuan Luo
- Andrzej Nowak
- Jinjin Li
2021 CHEMICAL PHYSICS LETTERS
We use electrical embedded-fragment QM method with both DFT/ωB97XD/6-31G* and MP2/6-31G* to investigate the phase transformations of olanzapine. Gibbs free energy calculations predict that form I is always the most stable structure and form II is the least stable one, while form IV is more stable than form III below about 200 K but less stable above this temperature, implying a polymorphic phase transformation. This may account for why form IV has only recently been discovered as crystallizing from a polymer-based molecular dispersion. The proposed methods may provide guidance for experiments and thus promote the study of phase transitions of pharmaceutical molecules.