2020 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2020

Pokaż wszystkie

Correlations between the wear of car brake friction materials and airborne wear particle emissions
- Wojciech Tarasiuk
- Karol Golak
- Yurii Tsybrii
- Oleksii Nosko
2020 Pełny tekst WEAR
Airborne wear particles emitted from transport vehicle brakes are one of the main sources of toxic metals in inhalable particulate matter. Prediction of wear particle emissions may become more accurate if the relationship between the wear and particle emission characteristics is known. An experimental study was performed to investigate proportional correlations between the mass wear, 0.01–0.42 μm particle emission measured by a NanoScan SMPS Nanoparticle Sizer (SMPS) and 0.3–10 μm particle emission measured by an Optical Particle Sizer (OPS). Several car brake low-metallic materials in the form of pin samples were tested against steel disc samples at different values of the contact pressure and sliding velocity. The pin-on-disc friction pair was placed in a clean chamber to eliminate external particle sources. The obtained results suggest a strong proportional correlation between the disc sample wear and pin sample wear. OPS and SMPS particle concentrations were also revealed to strongly correlate between each other. By contrast, the disc sample wear exhibited weak correlations with the particle concentrations for most of the materials.
Corrosion hazards and inhibitor protection in the seawater injection system on the Baltic sea rig
- Kinga Domańska
- Piotr Igliński
- Juliusz Orlikowski
- Krzysztof Żakowski
- Kazimierz Darowicki
2020 Pełny tekst International Journal of Corrosion and Scale Inhibition
Oil extraction efficiency in LOTOS Petrobaltic Company is increased by means of injection of seawater into an oilfield aquifer, which is implemented on the Baltic Beta rig, operating on the Baltic Sea. Operational experience has shown a significant degree of corrosion aggressiveness in the injected water, which necessitates frequent repairs of the seawater injection installation. Evaluation of the corrosion phenomena is crucial for rig platforms due to extremely high renovation costs and a negative impact on injected water quality. Chemical and microbiological analyses of seawater treated in the technological process have been carried out. Actions to estimate the corrosion risk in the installation and the estimated corrosion rates measured using an automated monitoring system are presented in this work. Monitoring of the corrosion rate conducted alongside measurements of the physicochemical properties of water allowed to identify the corrosion mechanisms of stainless steel in a seawater environment. Additionally, it became possible to assess the impact of the chlorine and carbon dioxide content on the corrosion rate, and to analyze the effectiveness of the corrosion inhibitor. The effectiveness of two types of commercial corrosion inhibitors has been estimated during different conditions.
Corrugated Sheeting as a Member of a Shear Panel Under Repeated Load—Experimental Test
- Natalia Korcz-Konkol
- Piotr Iwicki
2020 Pełny tekst Materials
In stressed-skin design, the cladding stiffening effect on structures is taken into account. However, the “traditional” design is more usual, wherein this effect is neglected. Even if the diaphragm actions are not regarded, in particular cases such as big sheds (and others), the parasitic (unwanted) stressed-skin action may occur with the result of leakage or even failure. The structures of this kind have already been built. Thus, an important question arises: How can one assess them if there is a need to correct or redesign them? What kind of non-destructive approach can be used to achieve that? Experimental tests of small-scale shear panels made of trapezoidal sheeting were designed in order to observe the behaviour of the diaphragm under increasing and repeated load. The tests were oriented toward force–displacement relations and strains in selected areas of the sheeting. The results revealed nonlinear, hysteretic force–displacement behaviour of the panel and the occurrence of the persistent deflections and stresses which remain even after the unloading. The relation among the stresses, force–displacement paths and modes of failure can be potentially used in monitoring systems of existing buildings in terms of parasitic stressed-skin action.
Cost-Efficient Bi-Layer Modeling of Antenna Input Characteristics Using Gradient Kriging Surrogates
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
- Muath Al-hasan
2020 Pełny tekst IEEE Access
Over the recent years, surrogate modeling has been playing an increasing role in the design of antenna structures. The main incentive is to mitigate the issues related to high cost of electromagnetic (EM)-based procedures. Among the various techniques, approximation surrogates are the most popular ones due to their flexibility and easy access. Notwithstanding, data-driven modeling of antenna characteristics is associated with serious practical issues, the primary one being the curse of dimensionality, particularly troublesome due to typically high nonlinearity of antenna responses. This limits applicability of conventional surrogates to simple structures described by a few parameters within narrow ranges thereof, which is grossly insufficient from the point of view of design utility. Many of these issues can be alleviated by the recently proposed constrained modeling techniques that restrict the surrogate domain to regions containing high-quality designs with respect to the relevant performance figures, which are identified using the pre-optimized reference designs at an extra computational effort. This paper proposes a methodology based on gradient-enhanced kriging (GEK). It enables a considerable reduction of the number of reference points required to construct the inverse surrogate (employed in surrogate model definition) by incorporating the sensitivity data into the nested kriging framework. Using two antenna examples, it is demonstrated to yield significant savings in terms of the surrogate model setup cost as compared to both conventional modeling methods and the original nested kriging.
Cost‐efficient performance‐driven modelling of multi‐band antennas by variable‐fidelity electromagnetic simulations and customized space mapping
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2020 INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS
Electromagnetic (EM) simulations have become an indispensable tool in the design of contemporary antennas. EM‐driven tasks, for example, parametric optimization, entail considerable computational efforts, which may be reduced by employing surrogate models. Yet, data‐driven modelling of antenna characteristics is largely hindered by the curse of dimensionality. This may be addressed using the recently reported domain‐confinement techniques, especially the nested‐kriging framework, which permits rendering of reliable surrogates over wide ranges of antenna parameters while greatly reducing the computational overhead of training data acquisition. Focused on modelling of multi‐band antennas, this paper attempts to reduce the cost of surrogate construction even further by incorporating variable‐fidelity simulations into the nested kriging. The principal challenge being design‐dependent frequency shifts between the models of various fidelities is handled through the development of a customized frequency scaling and output space mapping. Validation is carried out using a dual‐band dipole antenna modeled over broad ranges of operating conditions. A small training data set is sufficient to secure the predictive power comparable to that of the nested kriging model set up using solely high‐fidelity data, and by far exceeding the accuracy of conventional surrogates. Application examples for antenna optimization and experimental verification of the selected designs are also provided.
Cost-Efficient Surrogate Modeling of High-Frequency Structures Using Nested Kriging with Automated Adjustment of Model Domain Lateral Dimensions
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
2020 Pełny tekst AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
Surrogate models are becoming popular tools of choice in mitigating issues related to the excessive cost of electromagnetic (EM)-driven design of high-frequency structures. Among available techniques, approximation modeling is by far the most popular due to its versatility. In particular, the surrogates are exclusively based on the sampled simulation data with no need to involve engineering insight or problem-specific knowledge. Notwithstanding, a typically high nonlinearity of system outputs and the curse of dimensionality limit the applicability of conventional methods to relatively simple structures described by a few parameters within narrow ranges thereof. A recently reported nested kriging alleviates these difficulties from the perspective of an appropriate definition of the model domain. By focusing the modeling process on the region containing design that are optimized for the selected performance figures, it enables the construction of reliable surrogates over wide ranges of geometry/material parameters and operating conditions, both at a practically acceptable computational cost. The relative model domain thickness (i.e., its lateral-to-tangential size), determines the trade-off between the surrogate region of coverage and its predictive power, the former being essential for practical applications of the model, especially design optimization. This paper proposes a simple and computationally efficient procedure for automatic selection of the thickness parameter, which, in the original version of the method, was to be selected by the user. The importance of this aspect of the modeling process and the benefits of the proposed approach are demonstrated using a dual-band dipole antenna and miniaturized microstrip coupler.
Could thermal imaging supplement surface electromyography measurements for skeletal muscles?
- Bartłomiej Zagrodny
- Wiktoria Wojnicz
- Michał Ludwicki
- Jan Awrejcewicz
2020 Pełny tekst IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
Abstract—(1) Background: The aim of this study is to present the results of experiments in which surface electromyography (sEMG) and thermal imaging were used to assess muscle activation during gait and to verify the hypothesis that there is a relationship in the case of low fatigue level between sEMG measured muscle activation, assessed in the frequency domain, and thermal factors calculated as minimum, maximum, kurtosis, mean, median and mode from the area of interest. (2) Methods: Comparison of activity calculated from the recorded sEMG data for rectus femoris, biceps femoris, tibialis anterior and gastrocnemius medialis with thermal data obtained from the infrared vision. (3) Results: Data of fourteen healthy volunteers obtained during 10 minutes of treadmill gait are presented and analyzed. The analysis revealed statistically significant: linear correlations for rectus femoris (five moderate relationships) and gastrocnemius medialis (one good relationship); moderate nonlinear correlations for all examined muscles. Also, a detailed protocol for precise, repeatable thermal examination is presented. (4) Conclusions: Estimated moderate linear and non-linear correlations between thermal and electromyographic parameters are found for low level of muscle fatigue, which suggests that the presented method is useful in the analysis of muscle activation with the use of a thermal imaging as a complement to sEMG.
Coupled evolution of preferential paths for force and damage in the pre-failure regime in disordered and heterogeneous, quasi-brittle granular materials.
- A. Tordesillas
- S. Kahagalage
- C. Ras
- Michał Nitka
- Andrzej Tejchman-Konarzewski
2020 Pełny tekst Frontiers in Materials
Metoda elementów dyskretnych (DEM) została wykorzystana do symulacji betonu poddanego jednoosiowemu rozciąganiu. Beton modelowano jako materiał losową heterogeniczy 2/3-fazowy, złożony z cząstek kruszywa, matrycy cementowej i stref przejściowych międzyfazowej. Odkryto dowody na zoptymalizowaną transmisję siły, scharakteryzowaną przez dwa nowe wzorce, które przewidują i wyjaśniają sprzężoną ewolucję ścieżki siły i uszkodzenia od poziomu mikrostrukturalnego do poziomu makroskopowego. Pierwszy obejmuje możliwie najkrótsze ścieżki transmisji, które mogą przenosić siłę globalną. Ścieżki te przewidują łańcuchy sił rozciągających. Drugi wzór to wąskie gardło przepływu, ścieżka po zoptymalizowanej drodze, która jest podatna na zatory i pojawia się tam gdzie jest makro-rysa. Kooperacyjna ewolucja preferencyjnych ścieżki dla uszkodzeń i siły rzuca światło na to, dlaczego miejsca o najwyższym stężeniu naprężeń i uszkodzenia w początkowych stadiach obszaru przed zniszczeniem nie dostarczają realistycznego wskaźnika ostatecznego położenia makro-rysy.
COVID-19 and digital deprivation in Poland
- Marta Kuc-Czarnecka
2020 Pełny tekst Oeconomia Copernicana
Research background: The problem of digital deprivation is already known, but the COVID-19 pandemic has highlighted its negative consequences. A global change in the way of life, work and socialisation resulting from the epidemic has indicated that a basic level of digital integration is becoming necessary. During the lockdown, people were forced to use ICTs to adapt to a rapidly changing reality. Current experience with coronavirus pandemic shows that the transition to these extraordinary circumstances is not smooth. The inability to rapid conversion to the online world (due to a lack of skills or technical capabilities) significantly reduces professional mobility, hinders access to public services, and in the case of children, exposes them to the risk of remaining outside the remote education system. Purpose of the article: This research paper is addressing new issues of the impact of the COVID-19 pandemic on deepening and increasing the severity of e-exclusion. The goal of the paper is to indicate territorial areas in Poland, which are particularly vulnerable to digital deprivation due to infrastructural deficiencies. Methods: Raster data regarding landform, combined with vector data regarding population density and type of buildings as well as the location of BTS stations are used in so-called modelling overland paths (GIS method) to indicate areas vulnerable to the infrastructural digital divide. Findings & Value added: The research showed that 4% of Poles remain outside the Internet coverage, and additional ten percent of them out of the reach of the Internet, allowing efficient remote work or learning. The research indicated that digital 'accessibility gap' is underestimated. E-exclusion has become a pressing issue and requires urgent system solutions, in case of future lockdowns.
CROSS SECTIONS CALCULATIONS FOR ELECTRON SCATTERING FROM RHODANINE AND CYANOACETIC ACID
- Bożena Żywicka
- Paweł Możejko
2020 Pełny tekst PUBLICATIONS OF THE ASTRONOMICAL OBSERVATORY OF BELGRADE
Cross sections for electron-impact ionization and for elastic electron scattering for rhodanine (C3H3NOS2) and cyanoacetic acid (C3H3NO2) have been calculated in wide impinging electron energy range.
Crystal Growth, Structure, and Magnetism of the 2D Spin 1/2 Triangular Lattice Material Rb3Yb(PO4)2
- Shu Guo
- Ruidan Zhong
- Karolina Górnicka
- Tomasz Klimczuk
- Robert J. Cava
2020 CHEMISTRY OF MATERIALS
The single-crystal growth, crystal structure, heat capacity, and anisotropic magnetization characterization of Rb3Yb- (PO4)2, a Yb-based triangular lattice material, are presented. Single-crystal X-ray diffraction shows that Rb3Yb(PO4)2 exhibits [Yb(PO4)]∞ layers, with the Yb in an ordered plane of equilateral triangles. One phosphate group oxygen that is not a near neighbor of the magnetic Yb displays positional disorder. The temperaturedependent magnetization is anisotropic, with no long-range magnetic ordering observed for temperatures down to 50 mK. The low temperature heat capacity in the presence of an applied magnetic field is fitted very well by a Schottky anomaly with a linear magnetic-field-dependent gap between the ground and excited state energies. At 1.8 K, no magnetic transitions are seen for applied fields up to 90 kOe. Our results suggest that Rb3Yb(PO4)2 is a good candidate for displaying frustrated magnetism at low temperatures.
Crystal structure and physical properties of AePd1-xP1+x (Ae = Ca, Sr)
- Joanna Blawat
- Zuzanna Ryżyńska
- Tomasz Klimczuk
- Weiwei Xie
- Jin Rongying
2020 Materials Today Communications
We report the discovery of two new compounds AePd1-xP1+x (Ae = Ca, Sr) crystallized in different hexagonal structures. Single crystals of AePd1-xP1+x (Ae = Ca, Sr) are obtained using the Bi-flux method. Crystallographic analysis by both powder and single crystal X-ray diffraction shows that CaPd1-xP1+x crystallizes in a non-centrosymmetric hexagonal structure with the space group P-6m2 (No.187) and lattice parameters a = b = 4.0391(9) Å and c = 4.1026(9) Å, while SrPd1-xP1+x forms a centrosymmetric hexagonal structure with the space group P63/mmc (No. 194) and lattice parameters a = b = 4.102(2) Å and c = 8.713(4) Å. In both compounds, Pd and P atoms mix in the honeycomb layer with a higher amount of P. The electronic structure calculations show that the mixture of Pd and P atoms in the honeycomb network is critical to stabilize the crystal structures. AePd1-xP1+x (Ae = Ca, Sr) are diamagnetic metals confirmed by the magnetic susceptibility, electrical resistivity and specific heat.
Current Status, Barriers and Development Perspectives for Circular Bioeconomy in Polish South Baltic Area
- Dariusz Mikielewicz
- Paweł Dąbrowski
- Roksana Bochniak
- Aleksandra Gołąbek
2020 Pełny tekst Sustainability
The following article presents the current legal situation in Poland as well as in the European Union. Data on biomass production in the Polish South Baltic area were analyzed, along with an indication of the key sectors for the development of bioeconomy. Presentation of the current state of biomass management was made and areas necessary for development were indicated to facilitate the sustainable management of biomass and waste generated during its processing. Differences between regions in the Polish South Baltic Area show how an individual approach in each of these areas is required. During the analysis, the most important barrier to the implementation of the circular economy was distinguished, which is the lack of an appropriate legal framework. This is to be changed by the Circular Economy Road Map, adopted in 2019.
Current trends in analytical strategies for determination of polybrominated diphenyl ethers (PBDEs) in samples with different matrix compositions – Part 1.: Screening of new developments in sample preparation
- Monika Śmiełowska
- Bożena Zabiegała
2020 TRAC-TRENDS IN ANALYTICAL CHEMISTRY
Polybrominated diphenyl ethers (PBDEs) are ubiquitous compounds in the environment. Restrictions on the use of PBDEs introduced at the beginning of the 21st century have not eliminated these highly persistent and bioaccumulative compounds from the environment. Despite many existing regulations to control and phase out, extensive research on PBDEs is still necessary to fully evaluate the hazard their create to the environment. In most samples PBDEs occur at very low concentrations, which make analysis of these compounds difficult. The choice of an effective technique for the extraction of analytes that allows for their separation from interfering substances and the matrix is an important part of the analytical procedure for PBDEs determination. The paper presents a review of the literature on challenges related to the analysis of PBDEs in samples of different matrix compositions, the latest solutions used for sample preparation and future trends in sample preparation for PBDE analysis.
Current trends in analytical strategies for the determination of polybrominated diphenyl ethers (PBDEs) in samples with different matrix compositions – Part 2: New approaches to PBDEs determination
- Monika Śmiełowska
- Bożena Zabiegała
2020 TRAC-TRENDS IN ANALYTICAL CHEMISTRY
Herein, we review the latest technical solutions for polybrominated diphenyl ethers (PBDEs) determination in samples with different matrix compositions, largely focusing on gas chromatography but also presenting some liquid chromatography–based solutions. Moreover, we discuss the use of diverse sample injection techniques while considering the advantages and disadvantages of each injection system in the context of PBDEs analysis. For instance, the use of modern injection systems allowing the injection of larger-than-standard volumes may increase determination sensitivity, reduce analyte discrimination, and avoid thermally induced debromination. Attention is also paid to the possibility of using high-thermal-resistance chromatographic columns to decrease the extent of column bleeding and obtain better working conditions for the applied detection techniques, e.g., by increasing the signal-to-noise ratio. The importance of detector selection is emphasised, and data on the latest PBDE detection techniques are provided. Finally, we discuss the idea of using other devices in screening analysis to suspect the presence of PBDEs, mainly in polymer samples. As a future trends, we have provided data on the possibility of using modern solutions, including sensors.
Current trends in consumption of multimedia content using online streaming platforms: A user-centric survey
- Przemysław Falkowski-Gilski
- Tadeus Uhl
2020 Computer Science Review
In its early days, consumption of multimedia content was only possible at a stationary terminal device. The music player was located at home, and had to have a physical drive. Over the last decade, there has been an enormous increase in the number of online streaming platforms. These services enable users to consume rich multimedia content on various devices. Thanks to the widespread and availability of portable devices, any person connected to the Internet can access the same content, anytime and everywhere. This fact has forced wireless technologies to put significant emphasis on supporting high-quality content and on-demand services. However, energy consumption of handheld devices along with network bandwidth limitations are still the chief bottlenecks that today’s consumers face. This paper focuses on the consumption of multimedia content using mobile devices. It describes a user case study, carried out in 2019 on 150 individuals from three age groups, that is: 16–18, 19–24, and 25–35 years old, with 50 participants in each group. This survey covers the development of online streaming platforms and aims to help content providers, service providers and policy makers when designing and evaluating systems and services.
Curve Curvature Analysis of a Grain Trajectories in Variable Honing of Cylindrical Holes of Thin Wall Cylinder Liners as a Honing Process Optimization Strategy
- Piotr Sender
2020 Pełny tekst SpringerPlus
The main problem of honing of thin wall cylinder liners is a thermal distortion of honed holes. The higher the value of the temperature of the honed workpiece, the greater its holes deformation. The paper presents a method of reducing the temperature occurring in the honing process as a result of the application of a variable honing kinematics conditions with particular emphasis on the analysis of the effect of the value of the sum of radii of curve curvature on honed workpieces temperature . The lower value of the sum of curve curvatures radius of abrasive grain trajectories function affects the honed workpiece temperature decrease for a longer path length. The curve curvature radius of the abrasive grain paths function in the variable kinematic condition of honing of cylindrical holes can be used to improve honing of thin wall cylinder liners due to decreasing of amount temperature received in honing process.
Cutting model parameters from frame sawing of natural and impregnated Scots pine (Pinus sylvestris L.)
- Gerhard Sinn
- Daniel Chuchała
- Kazimierz Orłowski
- Piotr Taube
2020 Pełny tekst European Journal of Wood and Wood Products (HOLZ ALS ROH-UND WERKSTOFF)
In this paper, absolute and density normalized cutting model parameters of natural and impregnated Scots pine (Pinus sylvestris L.) are shown and a method for the calculation of their corresponding material properties in the principal material directions of wood is presented. The parameters were determined from measurements of cutting power on a sash gang saw, and are in detail the fracture toughness and the shear yield strength of wood. The cutting model used for fitting the data and calculating the parameters is based on a minimum energy criterion originally developed to describe an orthogonal single tooth cutting process where the chip of an isotropic material is built by shear. The effects of impregnation on wood are clearly visible in cutting power and model parameters, where for large chips less power is required compared to natural wood. Impregnated pine wood shows a reduced value of shear yield strength compared to natural pine whilst the correlated fracture toughness increased. The observed behavior might be explained by a lower moisture content of the impregnated pine compared to natural wood. Orthotropic fracture toughness and shear yield strength constants of natural and impregnated Scots pine might be used to predict cutting power for other cutting geometries and processes like circular sawing.
Cycling as a Sustainable Transport Alternative in Polish Cittaslow Towns
- Agnieszka Jaszczak
- Agnieszka Morawiak
- Joanna Żukowska
2020 Pełny tekst Sustainability
It is well known that growing motor traffic in urban areas causes air pollution and noise which affects the environment and public health. It is hardly surprising then that cycling should be used as an alternative mode of transport, not just in major cities but also in smaller ones including those that are members of the Cittaslow network. Their approach is based on sustainable development, care for the environment and transport solutions which will support a healthy lifestyle, reduced energy consumption and fewer emissions. The objective of the article is to analyse how well cycling is used as a means of transport in Polish Cittaslow towns. For this purpose, an analysis was conducted to understand how towns use their transport space to ensure accessibility and road safety. Reference is made to revitalisation programmes of Cittaslow towns with focus on what has been done to improve and build cycle paths in each town and outside of it. The work uses the following research methods: analysis of the literature, analysis of documents, including analysis of road incidents and traffic count. It has been demonstrated that cycling infrastructure in the towns under analysis has been marginalised. As a result, recommendations and suggestions are given which may inform decisions on how to build and transform cycling infrastructure in Cittaslow towns and in similar towns in Poland and abroad.
Cyclodextrin polymers as efficient adsorbents for removing toxic non-biodegradable pimavanserin from pharmaceutical wastewaters
- Koleta Hemine
- Anna Skwierawska
- Agata Kernstein
- Katarzyna Kozłowska-Tylingo
2020 Pełny tekst CHEMOSPHERE
Presence of even small amount of active pharmaceutical ingredients in the environment carries risks tohuman and animal health, presenting an important issue. The paper presents issues related to the newdrug - pimavanserin (PMV). Biological treatment efficiency of pimavanserin (PMV) was evaluated usinglab-scale Sequencing Batch Reactor (SBR). It has been shown to have a negative effect on aquatic or-ganisms by classifying it as a toxic compound (EC50¼8 mgL1). The level of biological degradation ofPMV was insufficient (37%) and intensively foam formation caused operational problems. For this reason,in this study polymers based on cyclodextrins (CDs) were synthesized and used as adsorbents alternativeto active carbons to effectively separate PMV from real industrial waste streams. Crosslinkedb- andg-CDpolymers (b- andg-NS), obtained in reaction with 1,10-carbonyldiimidazole (CDI), were fully character-ized by physicochemical methods. The adsorption equilibrium data were interpreted using Freundlichand Langmuir models. The sorption process was fast (60 s) and the efficiency of PMV separation frommodel waste waters was 93% and 81% forb- andg-NS, respectively. Maximum polymer capacity wasfound at 52.08 mg g1forb-NS and 23.26 mg g1forg-NS. The interactions of PMV with CDs have beenstudied and indicate that major mechanism of the sorption is based on supramolecular interaction andcapture to polymer network. Described biodegradable and reusable materials are perfect example ofcorrectly selected adsorbent for separation of target substance from postproduction aqueous media