2020 - Repozytorium publikacji - Politechnika Gdańska

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Analysis of the Dynamic Height Distribution at the Estuary of the Odra River Based on Gravimetric Measurements Acquired with the Use of a Light Survey Boat—A Case Study
- Jerzy Pyrchla
- Krzysztof Pyrchla
- Paulina Kowalska
- Arkadiusz Tomczak
- Grzegorz Zaniewicz
2020 Pełny tekst SENSORS
LaCoste) for determining the dynamic height along the Odra River, in northwest Poland. The gravity measurement campaign described in this article was conducted on a small, hybrid-powered survey vessel (overall length: 9.5 m). We discuss a method for processing the results of gravimetric measurements performed on a mobile platform affected by strong external disturbances. Because measurement noise in most cases consists of signals caused by non-ideal observation conditions, careful attempts were made to analyze and eliminate the noise. Two different data processing strategies were implemented, one for a 20 Hz gravity data stream and another for a 1 Hz data stream. A comparison of the achieved results is presented. A height reference level, consistent for the entire estuary, is critical for the construction of a safe waterway system, including 3D navigation with the dynamic estimation of under-keel clearance on the Odra and other Polish rivers. The campaign was conducted in an area where the accuracy of measurements (levelling and gravimetric) is of key importance for shipping safety. The shores in the presented area of interest are swampy, so watercraft-based measurements are preferred. The method described in the article can be successfully applied to measurements in all near-zero-depth areas.
Analysis of the radiation dose in UV-disinfection flow reactors.
- Wojciech Artichowicz
- Aneta Łuczkiewicz
- Jerzy Sawicki
2020 Pełny tekst Water
Theoretical considerations devoted to the variation of UV radiation doses in flow disinfection reactors are presented. The minimal time required by the fluid to pass the reactor was determined and combined with the radiation intensity. The active zones of the reactor were determined.
Analysis of the Ways to Identify Rail Running Surface Defects by Means of Vibration Signals
- Roksana Licow
- Franciszek Tomaszewski
2020 Pełny tekst Problemy Kolejnictwa
Th e article discusses a preliminary concept of a method enabling the identifi cation of chosen rail running surface defects, such as squats, spalling, and running surface defects, by analysing the parameters of vibration signals. It features a description of the methodology of the conducted tests, the scope thereof, and the selection of the measurement points with specifi c defect types. Th e article covers selected results of vibration tests, the results of analyses of recorded signals for defective track sections and those for control track sections. Th e presented measurement results have been obtained for the technical–operating conditions occurring on railway line no. 213 Reda – Hel and line no. 131 Chorzów Batory – Tczew. Th e preliminary test results and conclusions included in the article show that it is reasonable to pursue further research into the phenomena involving the utilisation of vibroacoustics in rail performance diagnostics.
Analysis of ultimate compressive strength of cracked plates with the use of DOE techniques
- Krzysztof Wołoszyk
- Yordan Garbatov
2020 Pełny tekst Polish Maritime Research
The objective of this work is to investigate the structural compressive response of plates with locked cracks accounting for all relevant factors and correlation between them. The nonlinear FE model considering both geometric and material nonlinearities is employed herein, and the FE model of the structural response of intact plates is validated with the available experimental data. In the common studies, based on One Factor at a Time analysis, some of the parameters and interactions between them are excluded. In the present study, the numerical investigations are conducted with the use of the Design of Experiments techniques, where all essential parameters and their interactions are adequately considered. With a total of 32 numerical analyses, the most influential factors and their interactions are identified. As a study outcome, empirical formulations, which allow for a fast estimation of the ultimate compressive strength of intact plates, plates with locked cracks, and repaired cracked plates, are derived. The developed formulations represent a fast and practical tool for estimating the ultimate compressive strength of intact, cracked, and repaired plates, which can be easily employed in the reliability analysis.
Analysis of Validation and Simplification of Timber-Frame Structure Design Stage with PU-Foam Insulation
- Marcin Szczepański
- Wojciech Migda
2020 Pełny tekst Sustainability
The transition from experimental studies to the realm of numerical simulations is often necessary for further studies, but very difficult at the same time. This is especially the case for extended seismic analysis and earthquake-resistant design. This paper describes an approach to moving from the experimental testing of an elementary part of a wood-frame building structure to a numerical model, with the use of a commercial engineering analysis software. In the presented approach, a timber-frame structure with polyurethane (PU)-foam insulation and OSB (oriented strand board) sheathing was exposed to dynamic excitation. The results were then used to generate a numerical 3D model of the wooden frame element. The process of creating the 3D model is explained with the necessary steps to reach validation. The details of the model, material properties, boundary conditions, and used elements are presented. Furthermore, the authors explain the technical possibilities for simplifying the numerical model in used software. Simplifying the model leads to a substantial reduction of calculation time without the loss of accuracy of results. Such a simplification is especially useful when conducting advanced numerical calculations in the field of seismic and dynamic resistant object design.
Analysis of Vibration and Acoustic Signals for Noncontact Measurement of Engine Rotation Speed
- Shan Xuansheng
- Tang Lu
- He Wen
- Radek Martinek
- Janusz Smulko
2020 Pełny tekst SENSORS
The non-contact measurement of engine speed can be realized by analyzing engine vibration frequency. However, the vibration signal is distorted by harmonics and noise in the measurement. This paper presents a novel method for the measurement of engine rotation speed by using the cross-correlation of vibration and acoustic signals. This method can enhance the same frequency components in engine vibration and acoustic signal. After cross-correlation processing, the energy centrobaric correction method is applied to estimate the accurate frequency of the engine’s vibration. This method can be implemented with a low-cost embedded system estimating the cross-correlation. Test results showed that this method outperformed the traditional vibration-based measurement method.
Analytical calculations of scattering lengths for a class of long-range potentials of interest for atomic physics
- Radosław Szmytkowski
2020 Pełny tekst JOURNAL OF MATHEMATICAL PHYSICS
We derive two equivalent analytical expressions for an $l$th partial-wave scattering length $a_{l}$ for central potentials with long-range tails of the form % \begin{math} \displaystyle V(r)=-\frac{\hbar^{2}}{2m}\frac{Br^{n-4}}{(r^{n-2}+R^{n-2})^{2}} -\frac{\hbar^{2}}{2m}\frac{C}{r^{2}(r^{n-2}+R^{n-2})}, \end{math} % ($r\geqslant r_{s}$, $R>0$). % For $C=0$, this family of potentials reduces to the Lenz potentials discussed in a similar context in our earlier works [Acta Phys. Pol.\ A 79 (1991) 613 and J.\ Phys.\ A 28 (1995) 7333]. The formulas for $a_{l}$ which we provide in this paper depend on the parameters $B$, $C$ and $R$ characterizing the tail of the potential, on the core radius $r_{s}$, as well as on the short-range scattering length $a_{ls}$, the latter being due to the core part of the potential. The procedure, which may be viewed as an analytical extrapolation from $a_{ls}$ to $a_{l}$, is relied on the fact that the general solution to the zero-energy radial Schr{\"o}dinger equation with the potential given above may be expressed analytically in terms of the \emph{generalized\/} associated Legendre functions.
Analyzing and Visualizing Government-Citizen Interactions on Twitter to Support Public Policy-making
- Rocio Hubert
- Elsa Estevez
- Ana Maguitman
- Tomasz Janowski
2020 Pełny tekst Digital Government: Research and Practice
Twitter is widely adopted by governments to communicate with citizens. It has become a major source of data for analyzing how governments communicate with citizens and how citizens respond to such communication, uncovering important insights about government-citizen interactions that could be used to support public policy-making. This article presents research that aims at developing a software tool called Twitter Analytics for Government Intelligence and Public Participation (TA4GIP) that applies sentiment analysis and visualization techniques to information collected from Twitter and presents the findings to policy-makers and other non-technical users to facilitate understanding and interpretation. The use of the tool is illustrated through the case study of Twitter communication carried by five government secretaries responsible for health, education, social development, labor, and environment sectors in Mexico, and corresponding citizen responses over a nine-month period. The case study demonstrates that TA4GIP helps identify and analyze relevant aspects of government presence and citizen participation on social media, such as abnormal activity, salient topics being discussed, citizen views about enacted public policies, correlations between types of emotions in responses to particular government announcements, topics that generate polarized reactions from citizens, and many others.
Analyzing the Effectiveness of the Brain–Computer Interface for Task Discerning Based on Machine Learning
- Jakub Browarczyk
- Adam Kurowski
- Bożena Kostek
2020 Pełny tekst SENSORS
The aim of the study is to compare electroencephalographic (EEG) signal feature extraction methods in the context of the effectiveness of the classification of brain activities. For classification, electroencephalographic signals were obtained using an EEG device from 17 subjects in three mental states (relaxation, excitation, and solving logical task). Blind source separation employing independent component analysis (ICA) was performed on obtained signals. Welch’s method, autoregressive modeling, and discrete wavelet transform were used for feature extraction. Principal component analysis (PCA) was performed in order to reduce the dimensionality of feature vectors. k-Nearest Neighbors (kNN), Support Vector Machines (SVM), and Neural Networks (NN) were employed for classification. Precision, recall, F1 score, as well as a discussion based on statistical analysis, were shown. The paper also contains code utilized in preprocessing and the main part of experiments.
Analyzing the Impact of Simulated Multispectral Images on Water Classification Accuracy by Means of Spectral Characteristics
- Krystyna Michałowska
- Ewa Głowienka
2020 Pełny tekst Geomatics and Environmental Engineering
Remote sensing is widely applied in examining the parameters of the state and quality of water. Spectral characteristics of water are strictly connected with the dispersion of electromagnetic radiation by suspended matter and the absorp-tion of radiation by water and chlorophyll a and b.Multispectral sensor ALI has bands within the ranges of electromagnetic radia-tion: blue and infrared, absent in sensors such as Landsat, SPOT, or Aster. The main goal of the article was to examine the influence of the presence of these bands on water classification accuracy carried out for simulated images ALI, Landsat, Spot, and Aster. The simulation of images was based on the hyper-spectral image from a Hyperion sensor. Due to the spectral properties of water, all the operations on the images were carried out for the set of bands in visible and near-infrared (VNIR) spectral range. In the framework of these studies, the impact of removing individual bands or sets of bands on the classification results was tested. Tests were carried out for the area of the water body of the Dobczyce Reservoir. It was observed that the lack of a spectral response in the infrared range of ALI image can reduce the accuracy of a classification by as much as 60%. On the other hand, the lack of blue and red bands in the data-set for the classification decreased the accuracy of water classification by 15% and 10%, respectively.
ANALYZING TITLES OF ECONOMY NEWS TO UNDERSTAND IMPACT OF COVID-19 ON ECONOMICAL SITUATION
- Olgun Aydin
- Cansu Altunbas
- Elvan Hayat
2020
Covid-19 affected the whole world in a short time, causing serious panic and uncertainty in society. Because it was an unprecedented disease, the medical community has worked hard to find out how to deal with it, and it continues to do so. The rapid spread of the disease, the shortage of hospital capacity and the increase in deaths drove the whole world to a closure, so to speak. In this time period, life in the world came to a halt. This also brought along many problems in terms of global economy. Many businesses announced their bankruptcy, many people were unemployed. Although the governments launched support packages, the lockdown caused huge damage to the global economy. In the light of this information, while studies continue intensively in the fields of medicine, chemistry and biology, researchers have accelerated their studies in fields such as data science, data analysis and open data as well. Within the scope of this study, in order to monitor and analyze the effects of Covid-19 on the economy, the economy news titles in the relevant period were collected and analyzed in detail using text mining techniques, and it was aimed to propose an alternative perspective to analyze the effect of the virus on the global economy.
Anodic titania nanotubes decorated with gold nanoparticles produced by laser-induced dewetting of thin metallic films
- Katarzyna Grochowska
- Nikolay Nedyalkov
- Jakub Karczewski
- Łukasz Haryński
- Gerard Śliwiński
- Katarzyna Siuzdak
2020 Pełny tekst Scientific Reports
Herein, we combine titania layers with gold species in a laser-supported process and report a substantial change of properties of the resulting heterostructures depending on the major processing parameters. Electrodes were fabricated via an anodisation process complemented with calcination to ensure a crystalline phase, and followed by magnetron sputtering of metallic films. The obtained TiO2 nanotubes with deposited thin (5, 10 nm) Au films were treated with a UV laser (355 nm) to form Au nanoparticles on top of the nanotubes. It was proven that selected laser working parameters ensure not only the formation of Au nanoparticles, but also simultaneously provide preservation of the initial tubular architecture, while above-threshold laser fluences result in partial destruction (melting) of the top layer of the nanotubes. For almost all of the samples, the crystalline phase of the nanotubes observed in Raman spectra was maintained independently of the laser processing parameters. Enhanced photoresponse up to ca 6 mA/cm2 was demonstrated by photoelectrochemical measurements on samples obtained by laser annealing of the 10 nm Au coating on a titania support. Moreover, a Mott–Schottky analysis indicated the dramatically increased (two orders of magnitude) concentration of donor density in the case of a laser-treated Au–TiO2 heterojunction compared to reference electrodes.
Antenna Modeling Using Variable-Fidelity EM Simulations and Constrained Co-Kriging
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
2020 Pełny tekst IEEE Access
Utilization of fast surrogate models has become a viable alternative to direct handling of fullwave electromagnetic (EM) simulations in EM-driven design. Their purpose is to alleviate the difficulties related to high computational cost of multiple simulations required by the common numerical procedures such as parametric optimization or uncertainty quantification. Yet, conventional data-driven (or approximation) modeling techniques are severely affected by the curse of dimensionality. This is a serious limitation when it comes to modeling of highly nonlinear antenna characteristics. In practice, general-purpose surrogates can be rendered for the structures described by a few parameters within limited ranges thereof, which is grossly insufficient from the utility point of view. This paper proposes a novel modeling approach involving variable-fidelity EM simulations incorporated into the recently reported nested kriging modeling framework. Combining the information contained in the densely sampled low- and sparsely sampled highfidelity models is realized using co-kriging. The resulting surrogate exhibits the predictive power comparable to the model constructed using exclusively high-fidelity data while offering significantly reduced setup cost. The advantages over conventional surrogates are pronounced even further. The presented modeling procedure is demonstrated using two antenna examples and further validated through the application case studies.
Anticancer Imidazoacridinone C-1311 is Effective in Androgen-Dependent and Androgen-Independent Prostate Cancer Cells
- Magdalena Niemira
- Barbara Borowa-Mazgaj
- Samuel B. Bader
- Adrianna Moszyńska
- Marcin Ratajewski
- Kaja Karaś
- Mirosław Kwaśniewski
- Adam Krętowski
- Zofia Mazerska
- Ester M. Hammond
- Anna Skwarska
2020 Pełny tekst Biomedicines
Androgen receptor (AR) plays a crutial role in prostate cancer (PCa) development and metastasis. Here, we reported potent anti-PCa activity of a small molecule imidazoacridinone C-1311. In AR-positive PCa cells, C-1311 was found to inhibit the transcriptional activity of AR uncovering a novel mechanism that may be relevant for its anticancer effect. Mechanistically, C-1311 decreased AR binding to prostate-specific antigen (PSA) promoter, reduced PSA protein level, and as shown by transcriptome sequenvcing, down-regulated numerous AR target genes. Importantly, AR-negative PCa cells were also sensitive to C-1311, suggesting a promising efficacy in androgen-independent PCa sub-type. Irrespective of AR status, C-1311 induced DNA damage, arrested cell cycle progression and induced apoptosis. RNA sequencing indicated on the significant differences in transcriptional response to C-1311 between PCa cells. Gene ontology analysis showed that in AR-dependent PCa cells, C-1311 mainly affected DNA damage response pathways. In contrast, in AR-independent PCa cells, C-1311 targeted cellular metabolism and inhibited gene regulating glycolysis and gluconeogenesis. Together, these results indicate that C-1311 warrants further development for the treatment of PCa.
Antimony substituted lanthanum orthoniobate proton conductor – structure and electronic properties.
- Aleksandra Mielewczyk-Gryń
- Sebastian Wachowski
- Agnieszka Witkowska
- Kacper Dzierzgowski
- Wojciech Skubida
- Konrad Świerczek
- Anna Regoutz
- David J. Payne
- Stephen Hull
- Hangfeng Zhang
- Isaac Abrahams
- Maria Gazda
2020 JOURNAL OF THE AMERICAN CERAMIC SOCIETY
X‐ray and neutron diffraction have been utilized to analyze the crystalline and electronic structure of lanthanum orthoniobate substituted by antimony. Using X‐ray absorption spectroscopy and photoelectron spectroscopy, changes in the electronic structure of the material upon substitution have been analyzed. The structural transition temperature between fergusonite and scheelite phases for 30 mol% antimony substitution was found to be 15 °C. Based on the neutron data, the oxygen nonstoichiometry was found to be relatively low. Moreover, no influence on the position of the valence band maximum was observed. The influence of the protonation on the electronic structure of constituent oxides has been studied. Absorption data show that the incorporation of protonic defects into the lanthanum orthoniobate structure leads to changes in lanthanum electronic structure and a decrease in the density of unoccupied electronic states.
Application of 3D printing metal powder technology in the manufacture of components with complex geometries
- Mariusz Deja
- Dawid Zieliński
2020 Pełny tekst Mechanik
The possibilities of using 3D printing powder technologies for making objects with complex geometries were presented. For this purpose, selected examples of elements with different geometries were used, which were built using metal powder methods – DMLS (direct metal laser sintering) / SLM (selective laser melting). Simultaneously, the indicated elements concern those areas of industry where 3D printing technology has been widely used in recent years, i.e. maritime and aerospace industries. Also, the metal 3D printing process was characterized by a description of the particular stages of model building. The directions of further development of the above mentioned 3D printing methods and the areas of possible applications of the 3D printed parts were presented, respectively.
Application of Analytic Signal and Smooth Interpolation in Pulse Width Modulation for Conventional Matrix Converters
- Paweł Szczepankowski
- Patrick Wheeler
- Tomasz Bajdecki
2020 Pełny tekst IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
The paper proposes an alternative and novel approach to the PWM duty cycles computation for Conventional Matrix Converters (CMC) fed by balanced, unbalanced or non–sinusoidal AC voltage sources. The presented solution simplifies the prototyping of direct modulation algorithms. PWM duty cycles are calculated faster by the smooth interpolation technique, using only vector coordinates, without trigonometric functions and angles. Both input voltages and output reference voltages are expressed by analytic signals in the proposed direct modulation. Input voltages are represented by the rotating vector collection in the two–dimensional Cartesian coordinate system. All reference output voltages are located inside the triangular surface, named here as the voltage synthesis field, formed by these rotating vectors. A certain degree of reference signals placement freedom allows to maximize the voltage transfer ratio to 0:866 with less switching compared to the Optimum–Venturini direct method. The proposed solution was verified by simulations and experiments for CMC3xk. The comparison with the Optimum–Venturini modulation is included. The proposed PWM duty cycle computation approach can also be applied to multiphase CMC converters for any number of inputs as well as outputs.
APPLICATION OF APRIORI ALGORITHM IN THE LAMINATION PROCESS IN YACHT PRODUCTION
- Tacjana Niksa-Rynkiewicz
- Michał Landowski
- Paweł Szalewski
2020 Pełny tekst Polish Maritime Research
The article specifies the dependence of defects occurring in the lamination process in the production of yachts. Despite great knowledge about their genesis, they cannot be completely eliminated. Authentic data obtained through cooperation with one of the Polish yacht shipyards during the years 2013–2017 were used for the analysis. To perform a simulation, the sample size was observed in 1450 samples, consisting of 6 models of yachts with closed and open deck. Finding the dependence of the occurrence of specific defects will allow for faster procedures and more effective quality control, which will contribute to lower costs. The use of new methods based on artificial intelligence related to Big Data allows for easier observation of dependencies in the complex structure of data from yacht production. The association rules were defined using the algorithm Apriori and define interdependent defects. A number of dependencies were found for the occurrence of production defects not obvious to technologists, but occurring with a high probability of coexistence. The presented research results may allow the planning process of production tasks to be improved.
Application of BiOClnBrm photocatalyst to cytostatic drugs removal from water; mechanism and toxicity assessment
- Patrycja Wilczewska
- Andrea Elisabeth Natasha Ona
- Aleksandra Bielicka-giełdoń
- Anna Malankowska
- Karol Tabaka
- Jacek Ryl
- Filip Pniewski
- Ewa Siedlecka
2020 Pełny tekst SEPARATION AND PURIFICATION TECHNOLOGY
The photocatalytic activity of series of BiOClnBrm photocatalysts toward degradation and mineralization of the cytostatic drugs 5-fluorouracil (5-FU) and imatinib mesylate (IMA) both singly and in their mixture under simulated solar and visible light irradiation has been investigated. Screening test revealed that among BiOClnBrm photocatalysts synthesized by a solvothermal method, the one with molar 1.3Cl/0.7Br ratio was the most efficient in 5-FU removal under UV-Vis irradiation. The dose 200 mg L-1 and 6.3 pH were optimal to effective removal of 5-FU. The BiOCl1.3Br0.7 was successfully used to 5-FU and IMA removal singly and in their mixture under simulated solar and visible light irradiation. Scavenging experiments showed that h+ and •O2- were the major oxidative species participated in both drugs degradation. In presence of IMA, 5-FU removal was significantly depressed. In singly drug solutions and in the mixture of drugs, the presence of inorganic ions such as Cl−, SO42−, and NO3- significantly hindered 5-FU photocatalytic degradation, and increased the adsorption of IMA onto the photocatalyst surface in dark phase. The HCO3− anion, Fe3+ and Ag+ cations accelerated the 5-FU removal, while Ca2+ showed no impact on the process. The transformation products of 5-FU and IMA were identified by LC-MS revealing that hydroxylation and oxidation were the main transformation pathways, under the all studied systems. Some of intermediates were indicated for the first time in heterogeneous photocatalysis. The defluorination of 5-FU by the reaction with photogenerated e- was also possible. Furthermore, the alga toxicity assay was investigated using Chlorella vulgaris. A reduction of toxicity in effluents after photocatalytic degradation of both drugs singly and in their mixture was observed.
Application of Diffusion Models in the Analysis of Financial Markets: Evidence on Exchange Traded Funds in Europe
- Ewa Lechman
- Adam Marszk
2020 Pełny tekst Risks
Exchange traded funds (ETFs) are financial innovations that may be considered as a part of the index financial instruments category, together with stock index derivatives. The aim of this paper is to explore the trajectories and formulates predictions regarding the spread of ETFs on the financial markets in six European countries. It demonstrates ETFs’ development trajectories with regard to stock index futures and options that may be considered as their substitutes, e.g., in risk management. In this paper, we use mathematical models of the diffusion of innovation that allow unveiling the evolutionary patterns of turnover of ETFs; the time span of the analysis is 2004–2015, i.e., the period of dynamic changes on the European ETF markets. Such an approach has so far rarely been applied in this field of research. Our findings indicate that the development of ETF markets has been strongest in Italy and France and weaker in the other countries, especially Poland and Hungary. The results highlight significant differences among European countries and prove that diffusion has not taken place in all the cases; there are also considerable differences in the predicted development paths.