Repozytorium publikacji - Politechnika Gdańska

Ustawienia strony

english
Repozytorium publikacji
Politechniki Gdańskiej

Pokaż publikacje z roku

Ostatnie pozycje

  • Identification of Fast Time-varying Communication Channels Using the Preestimation Technique
    • Maciej Niedźwiecki
    • Artur Gańcza
    • Piotr Kaczmarek
    2021 Pełny tekst IFAC-PapersOnLine

    Accurate identification of stochastic systems with fast-varying parameters is a challenging task which cannot be accomplished using model-free estimation methods, such as weighted least squares, which assume only that system coefficients can be regarded as locally constant. The current state-of-the-art solutions are based on the assumption that system parameters can be locally approximated by a linear combination of appropriately chosen basis functions. The paper shows that tracking performance of the resulting local basis function estimation algorithms can be further improved by means of regularization. The method is illustrated by an important recent application - identification of fast time-varying acoustic channels used in underwater communication.

  • Identification of novel halogenated naturally occurring compounds in marine biota by high-resolution mass spectrometry and combined screening approaches
    • Lidia Belova
    • Yukiko Fujii
    • Paulien Cleys
    • Monika Śmiełowska
    • Koichi Haraguchi
    • Adrian Covaci
    2021 Pełny tekst ENVIRONMENTAL POLLUTION

    Marine animals, plants or bacteria are a source of bioactive naturally-occurring halogenated compounds (NHCs) such as bromophenols (BPs), bromoanisoles (BAs) and hydroxylated or methoxylated analogues of polybrominated diphenyl ethers (HO-PBDEs, MeO-PBDEs) and bromobiphenyls (HO-BBs, MeO-BBs). This study applied a comprehensive screening approach using liquid chromatography high-resolution mass spectrometry and combining target, suspect and non-target screening with the aim to identify new hydroxylated NHCs which might be missed by commonly applied gas chromatographic methods. 24 alga samples, 4 sea sponge samples and 7 samples of other invertebrates were screened. Target screening was based on 19 available reference standards of BPs, (di)OH-BDEs and diOH-BBs and yielded seven unequivocally identified compounds. 6OH-BDE47 was the most frequently detected compound with a detection frequency of 31%. Suspect screening yielded two additional compounds identified in alga samples as well as 17 and 8 compounds identified in sea sponge samples of Lamellodysidea sp. and Callyspongia sp., respectively. The suspect screening results presented here confirmed the findings of previous studies conducted on sea sponge samples of Lamellodysidea sp. and Callyspongia sp. Additionally, in Lamellodysidea sp. and Callyspongia sp. 13 and 4 newly identified NHCs are reported including heptabrominated diOH-BDE, monochlorinated pentabrominated diOH-BDE, hexabrominated OH–MeO-BDE and others. Non-target screening allowed the identification of 31 and 20 polyhalogenated compounds in Lamellodysidea sp. and Callyspongia sp. samples, respectively. Based on the obtained fragmentation spectra, polybrominated dihydroxylated diphenoxybenzenes (diOH-PBDPBs), such as hepta-, octa- and nonabrominated diOH-BDPBs, could be identified in both species. To our knowledge, this study is the first report on the environmental presence of OH-PBDPBs.

  • Identification of residual force in static load tests on instrumented screw displacement piles
    • Adam Krasiński
    • Mateusz Wiszniewski
    2021 Pełny tekst Studia Geotechnica et Mechanica

    Occurrence of the so-called residual force of an unknown value significantly disturbs interpretation of static load tests performed on piles equipped with additional measuring instruments. Screw displacement piles are the piling technology in which the residual force phenomenon is very common. Its formation mechanism is closely related to the installation method of this type of piles, which initiates generation of negative pile skin friction without any additional external factors. Knowledge of the value and distribution of a residual force (trapped in a pile shaft before starting the load test) is a condition necessary for the proper interpretation of instrumented pile test results. In this article, a clear and easy-to-use method of residual force identification, based on the analysis of shaft deformations recorded during pile unloading is presented. The method was successfully verified on two pile examples and proved to be effective and practical.

  • Identification of synergistic and antagonistic actions of environmental pollutants: Bisphenols A, S and F in the presence of DEP, DBP, BADGE and BADGE·2HCl in three component mixtures
    • Natalia Jatkowska
    • Błażej Kudłak
    • Patrycja Lewandowska
    • Wen Liu
    • Michael Williams
    • Helgi B. Schiöth
    2021 SCIENCE OF THE TOTAL ENVIRONMENT

    Ecosystems are facing increased pressure due to the emission of many classes of emerging contaminants. However, very little is known about the interactions of these pollutants, such as bisphenols (BPs), plasticizers or pharmaceuticals. By employing bioluminescent bacteria (Microtox assay), we were able to define interactions between selected emerging pollutants (namely BPA, BPS, BPF, BADGE, BADGE·2HCl, DEP, DBP) in ternary mixtures, at environmentally relevant concentration levels (down to as low as 1.89, 1.42, 3.08, and 0.326 μM for, respectively, BPA, BPF, BPS and BADGE·2HCl).Weprovide the first systematic analysis of bisphenols and phthalates in three component mixtures. Using this system, we performed toxicity modelling with concentration addition (CA) and independent action (IA) approaches, followed by data interpretation using Model Deviation Ratio (MDR) evaluation. Interestingly, we mathematically and experimentally confirmed a novel synergy between BPA, BADGE and BADGE·2HCl. The synergy of BPA, BADGE and BADGE·2HCl is distinct, with both models suggesting these analytes have a similar mode of action (MOA).

  • Identifying and Mitigating the Negative Effects of Power in Organizations
    • Paweł Ziemiański
    2021 Pełny tekst Journal of Applied Social Science

    This article investigates the possible negative effects of power in organizations. It demonstrates how holding power may affect an individual’s perception of others, actions, and cognition. Ways in which power may have a detrimental effect on different aspects of a manager’s functioning within an organization, including building relationships, communication, and performance are analyzed. It is argued that individuals are unaware of these effects, and thus it is necessary to introduce methods of their diagnosis and countermeasures on the organizational level. In addition, negative phenomena associated with the power’s distribution among organizations’ units and its structural aspects are analyzed. A set of questions is proposed, which can be used by individuals and organizations to reveal the extent to which adverse effects of power are present in an organization. These inquiries can be used to design and introduce specific countermeasures and improve communications and the quality of interactions within organizations. Selected countermeasures are also proposed in the article.

  • IFE: NN-aided Instantaneous Pitch Estimation
    • Marek Blok
    • Jan Banaś
    • Mariusz Pietrołaj
    2021 Pełny tekst

    Pitch estimation is still an open issue in contemporary signal processing research. Nowadays, growing momentum of machine learning techniques application in the data-driven society allows for tackling this problem from a new perspective. This work leverages such an opportunity to propose a refined Instantaneous Frequency and power based pitch Estimator method called IFE. It incorporates deep neural network based pitch estimation with audio front end used for extraction of instantaneous frequency and power of signal components. A thorough results analysis is performed and major advantages and shortcomings of this method are identified, leading to a wide array of suggestions for future improvement While IFE exhibits an instantaneous temporal resolution, a comparison is made against state-of-the-art pitch estimators operating on time windows, proving a comparable degree of prediction accuracy (up to 6% accuracy improvement) while maintaining the advantage of higher temporal resolution.

  • Image-based numerical modeling of the tensile deformation behavior and mechanical properties of additive manufactured Ti–6Al–4V diamond lattice structures
    • M. Doroszko
    • A. Falkowska
    • Andrzej Seweryn
    2021 Pełny tekst MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

    This work concerns the numerical modeling of the deformation process and mechanical properties of structures obtained by the additive method laser power bed fusion (LPBF). The investigation uses diamond structures of Ti–6Al–4V titanium implantation alloy with various relative densities. To model the process of tensile deformation of the materials, geometric models were used, mapping the realistic shape of the examined structures. To recreate the geometry of the samples, computed tomography (CT) and microtomography (micro-CT) were used, which allowed to obtain two accuracy levels of the mapping details of the investigated structures shape. Taking into account the nonlinearity of the material in the computational model makes it possible to model the deformation process of cellular materials until the fracture initiation. On the basis of the performed calculations using the finite element method (FEM), the stress and strain distributions in deformed structures were obtained and analyzed. The relationship between the shape of cellular structures and their effective mechanical properties on a macroscopic scale was investigated. The influence of the accuracy of the structures shape mapping on their strength properties and stress and strain distributions was also described. On the basis of the conducted research, fracture initiation localizations in titanium cellular structures were indicated. Finally, the results of the numerical calculations were verified by experimental tests.

  • Imaging of Increasing Damage in Steel Plates Using Lamb Waves and Ultrasound Computed Tomography
    • Monika Zielińska
    • Magdalena Rucka
    2021 Pełny tekst Materials

    This paper concerns inspection of steel plates, with particular emphasis on the assessment of in-creasing damage. Non-destructive tests were performed on four plates, one of which was un-damaged, while the remaining three had a defects in the form of circular holes with a diameter of 2, 5, and 10 cm. Guided Lamb waves were used in the research, and the image reconstruction was performed using ultrasound computed tomography. The damage size was estimated by tracking the real course of rays and densifying the pixel grid into which the object was divided. The re-sults showed the great potential of ultrasound tomography in detecting defects in steel elements, together with the possibility of estimating damage size.

  • Immersive Technologies that Aid Additive Manufacturing Processes in CBRN Defence Industry
    • Małgorzata Gawlik-Kobylińska
    • Paweł Maciejewski
    • Jacek Lebiedź
    • Alexander Kravcov
    2021 International Journal on Information Technologies and Security

    Testing unique devices or their counterparts for CBRN (C-chemical, B-biological, R-radiological, N-nuclear) defense relies on additive manufacturing processes. Immersive technologies aid additive manufacturing. Their use not only helps understand the manufacturing processes, but also improves the design and quality of the products. This article aims to propose an approach to testing CBRN reconnaissance hand-held products developed by additive manufacturing. According to the approach, tactical training with the use of the 3D object or their printed versions can be helpful in military products development by providing data on user experience. Training for testing can enhance their quality regarding intuitiveness and easiness in use. It can be concluded that the fast-evolving technological landscape requires novel approaches in developing and testing military products.

  • IMMIGRANTY IZ STRAN BYVSHEGO SSSR I POL'SKIY GOSUDARSTVENNYY INTERES
    • Krystyna Gomółka
    2021

    Пребывание иммигрантов из государств бывшего СССР в Польше регулируется положениями международного, европейского и национального права. Соотношение между въехавшими в Польшу на постоянное место жительства и выехавшими из нее в 2004- 2015 гг. было отрицательным, только в 2016 г. в Польшу прибыло больше мигрантов, чем уехало из нее. В 2004 г. иммигранты из государств бывшего СССР составляли 61% общего количества иммигрантов, въехавших в Польшу для проживания на постоянной основе, тогда как в 2016 г. – 54,6%. Наиболее многочисленная группа иммигрантов прибывала в страну на определенное время для работы или учебы. Вплоть до 2017 г. больше половины граждан стран бывшего СССР устраивались на работу нелегально. Однако ситуация изменилась после принятия 20 июля 2017 г. поправок в Закон о содействии занятости и организациях рынка труда. Иностранцы, приезжающие из Армении, Белоруссии, Грузии, Молдавии, России и Украины, могут воспользоваться упрощенной процедурой доступа к рынку труда для устройства на работу на краткосрочный период. Согласно поправкам в закон, наряду с разрешениями на работу, которые выдает воевода на срок до трех лет, было введено разрешение на сезонную работу, выдаваемое старостой на срок до девяти месяцев в течение календарного года. В этот период у работодателей существенно возросла потребность в рабочей силе с востока, особенно в работниках с Украины. Рост числа иностранцев на польском рынке труда – это также вызов полякам, возвращающимся на родину из Великобритании. Сложно однозначно определить, сколько поляков вернется насовсем и найдут ли они работу, соответствующую их знаниям и полученному опыту, а также в какой степени они будут вынуждены конкурировать с иммигрантами из государств бывшего СССР

  • Impact of AI-Based Tools and Urban Big Data Analytics on the Design and Planning of Cities
    • Dorota Kamrowska-Załuska
    2021 Pełny tekst Land

    Wide access to large volumes of urban big data and artificial intelligence (AI)-based tools allow performing new analyses that were previously impossible due to the lack of data or their high aggregation. This paper aims to assess the possibilities of the use of urban big data analytics based on AI-related tools to support the design and planning of cities. To this end, the author introduces a conceptual framework to assess the influence of the emergence of these tools on the design and planning of the cities in the context of urban change. In this paper, the implications of the application of artificial-intelligence-based tools and geo-localised big data, both in solving specific research problems in the field of urban planning and design as well as on planning practice, are discussed. The paper is concluded with both cognitive conclusions and recommendations for planning practice. It is directed towards urban planners interested in the emerging urban big data analytics based on AI-related tools and towards urban theorists working on new methods of describing urban change

  • Impact of digital technologies on reliability of risk forecasting models - case study of enterprises in three global financial market regions
    • Tomasz Korol
    2021

    This chapter focuses on the evaluation of impact of ICT on reliability of financial risk forecasting models. Presented study shows how the development of ICT can improve the effectiveness of such models. Determining a firm’s financial risk is one of the most interesting topics for investors and decision-makers. The multifaceted goal of the presented research is to separately estimate five traditional statistical and five soft computing models for enterprises in Far-East Asia, Europe and Latin America (together with offering 30 different forecasting models) and to identify the most effective method for predicting the financial failure of enterprises in the short-, medium- and long-term for firms in each region. A further goal is to evaluate which method is characterized by the smallest decrease of effectiveness in increasing the forecast horizon. Thus it will allow to compare the behavior of traditional and the latest IT techniques. This study is one of the first attempts in the literature to estimate a bankruptcy forecasting model using such a wide range of methods and focusing on enterprises in three different financial markets.

  • Impact of dyes isomerization effect on the charge transfer phenomenon occurring on the dye/nanosemiconductor interface
    • Oleksandr Korolevych
    • Maciej Zalas
    • Waldemar Stampor
    • Abdel Hadi Kassiba
    • Małgorzata Makowska-janusik
    2021 SOLAR ENERGY MATERIALS AND SOLAR CELLS

    The present work aimed to find the answer how does the isomerization of the Ru based dyes affect the overall photon-to-current efficiency of the DSSCs and to explain the charge transfer phenomenon occurring on the dye/ nanosemiconductor interface. Therefore, electronic and optical properties of three bipyridine derivatives anchored on the TiO2 electrode were investigated by computational simulations based on quantum chemistry codes performed on a cluster model and the predictions compared with experimental responses. The quantum chemical calculations carried out for the para-, meta- and ortho-isomers has given the possibility to explain the role of an anchor group position in the DSSC devices design. An in-depth analysis of the obtained data shows that the nature of the bonding between the anchor groups and the semiconducting nanoparticles affects the charge transfer at the interfaces. The electronic properties obtained for the hybrid systems and their components indicate that solar cells with the para-derivatives of the Ru based dyes as sensitizers exhibit the highest photo conversion efficiency. The observed phenomenon was explained based on the photogenerated excitons in the organic groups and their dissociation at the dye/semiconductor interfaces to ensure the free charge carriers

  • Impact of Geometrical Imperfections on Estimation of Buckling and Limit Loads in a Silo Segment Using the Vibration Correlation Technique
    • Łukasz Żmuda-Trzebiatowski
    • Piotr Iwicki
    2021 Pełny tekst Materials

    The paper examines effectiveness of the vibration correlation technique which allows determining the buckling or limit loads by means of measured natural frequencies of structures. A steel silo segment with a corrugated wall, stiffened with cold-formed channel section columns was analysed. The investigations included numerical analyses of: linear buckling, dynamic eigenvalue and geometrically static non-linear problems. Both perfect and imperfect geometries were considered. Initial geometrical imperfections included first and second buckling and vibration mode shapes with three amplitudes. The vibration correlation technique proved to be useful in estimating limit or buckling loads. It was very efficient in the case of small and medium imperfection magnitudes. The significant deviations between the predicted and calculated buckling and limit loads occurred when large imperfections were considered.

  • Impact of the Alkyl Side Chains of Cations and Anions on the Activity and Renaturation of Lysozyme: A Systematic Study Performed Using Six Amino‐Acid‐Based Ionic Liquids
    • Paulina Rakowska
    • Adam Kloskowski
    2021 ChemistrySelect

    The impact of the structure of ionic liquid on the activity and renaturation of lysozyme from the hen egg white (HEWL) was investigated. A set of six ionic liquids based on morpholinium cation and N-acylated amino acids as anions were exploited. The matrix used was based on two homologous series: one with N-acetyl-L-valinate [Val] as a common anion and morpholinium cation with a different number of carbon atoms in the n-alkyl chain (n=2, 4, 6, 8); and second, a common N-butyl-N-methylmorpholinium cation and different N-acylated amino acids. Interactions of ionic liquids with HEWL were explored by analyzing the changes in the activity of the enzyme based on the rate of hydrolysis of a β-1,4-glycosidic bond between components of peptidoglycan in the cell wall of Micrococcus luteus bacteria. The results demonstrated various mechanisms of interaction of cations and anions with HEWL, and hence, different trends in the association between the number of carbon atoms and the given property.

  • Impact response of novel layered two stage fibrous composite slabs with different support type
    • R. Rithanyaa
    • G. Murali
    • M.p. Salaimanimagudam
    • Roman Fediuk
    • Hakim Abdelgader
    • A. Siva
    2021 Structures

    The performance of novel Layered Two Stage Fibrous Composite slabs (LTSFC) was pioneered under falling mass collisions using a combined experimental and numerical study. Such LTSFC slabs consist of three layers with and without the insertion of glass fibre mesh between the layers. LTSFC techniques were used to fabricate the composite slabs with three layers including 3%, 1.5%, and 3% of fibre content for the top, middle, and bottom layers respectively. Sixteen MLPAFC square slabs were cast with only short hooked end fibres and tested under falling mass collisions by amending two parameters namely the type of support (fixed and hinge) and support layout. Two distinct support layouts on two types of support were considered and tested with and without the glass fibre mesh between layers of LTSFC. A glass fibre mesh was introduced between the three layers to block crack growth propagation and absorb additional collision energy. The glass fibre mesh insertion between the layers and the LTSFC production technique were considered as novel modifications. A numerical study using Auto desk Fusion 360 was conducted and compared with experimental results. The numerical results showed fair agreement with the experimental test results. Based on the validated numerical models, collision energy and cracking pattern evolution were studied. The findings indicated that the glass fibre mesh insertion between the layers combined with steel fibres disrupted crack proliferation, thus exhibiting superior engrossed collision energy and postponing crack growth. Additionally, the engrossed collision energy at crack initiation and ultimate crack for the slabs with four sides fixed and hinged support were greater with respect to two opposite sides fixed and hinged support. Numerical values were in reasonable agreement with the experimental values in terms of collision energy and cracking patterns.

  • imPlatelet classifier: image‐converted RNA biomarker profiles enable blood‐based cancer diagnostics
    • Krzysztof Pastuszak
    • Anna Supernat
    • Myron G Best
    • Sjors In ‘t Veld
    • Sylwia Łapińska‐Szumczyk
    • Anna Łojkowska
    • Robert Różański
    • Anna Żaczek
    • Jacek Jassem
    • Thomas Würdinger
    • Tomasz Stokowy
    2021 Pełny tekst Molecular Oncology

    Liquid biopsies offer a minimally invasive sample collection, outperforming traditional biopsies employed for cancer evaluation. The widely used material is blood, which is the source of tumor-educated platelets. Here, we developed the imPlatelet classifier, which converts RNA-sequenced platelet data into images in which each pixel corresponds to the expression level of a certain gene. Biological knowledge from the Kyoto Encyclopedia of Genes and Genomes was also implemented to improve accuracy. Images obtained from samples can then be compared against standard images for specific cancers to determine a diagnosis. We tested imPlatelet on a cohort of 401 non-small cell lung cancer patients, 62 sarcoma patients and 28 ovarian cancer patients. imPlatelet provided excellent discrimination between lung cancer cases and healthy controls, with accuracy equal to 1 in the independent dataset. When discriminating between non-cancer cases and sarcoma or ovarian cancer patients, accuracy equaled 0.91 or 0.95, respectively, in the independent datasets. According to our knowledge, this is the first study implementing an image-based deep-learning approach combined with biological knowledge to classify human samples. The performance of imPlatelet considerably exceeds previously published methods and our own alternative attempts of sample discrimination. We show that the deep-learning image-based classifier accurately identifies cancer, even when a limited number of samples is available.

  • Implementacja wykrywalnych usług typu REST na platformie Jakarta EE
    • Michał Wójcik
    2021

    Niniejszy rozdział przedstawia propozycję w jaki sposób może być realizowana implementacja wykrywalnych usług sieciowych opartych na stylu architektonicznym REST na platformie Jakarta EE. Zostały tutaj przedstawione zarówno podstawy teoretyczne niezależne od zastosowanej platformy technologicznej, jak i szczegóły implementacji w technologii JAX-RS wchodzącej w skład platformy Jakarta EE. W szczególności zostały tutaj przedstawione sposoby poprawnego budowania hierarchicznego API zgodnie z modelem dojrzałości Richardsona jak i techniki opisywania reprezentacji zwracanej przez usługi sieciowe zgodnie ograniczeniem HATEOAS i językiem opisu HAL. Wszystkie aspekty teoretyczne poruszane w rozdziale zostały poparte praktyczną implementacją dostępną publicznie w postaci repozytorium kodu opartego na systemie kontroli wersji Git.

  • Implementation of Coprocessor for Integer Multiple Precision Arithmetic on Zynq Ultrascale+ MPSoC
    • Tomasz Stefański
    • Kamil Rudnicki
    • Wojciech Żebrowski
    2021

    Recently, we have opened the source code of coprocessor for multiple-precision arithmetic (MPA). In this contribution, the implementation and benchmarking results for this MPA coprocessor are presented on modern Zynq Ultrascale+ multiprocessor system on chip, which combines field-programmable gate array with quad-core ARM Cortex-A53 64-bit central processing unit (CPU). In our benchmark, a single coprocessor can be up to 4.5 times faster than a single CPU core within the same chip emulating MPA using a software library.

  • Implementation of Extended Kalman Filter with Optimized Execution Time for Sensorless Control of a PMSM Using ARM Cortex-M3 Microcontroller
    • Justas Dilys
    • Voitech Stankevič
    • Krzysztof Łuksza
    2021 Pełny tekst ENERGIES

    This paper addresses the implementation and optimization of an Extended Kalman Filter (EKF) for the Permanent Magnet Synchronous Motor (PMSM) sensorless control using an ARM Cortex-M3 microcontroller. A various optimization levels based on arithmetic calculation reduction was implemented in ARM Cortex-M3 microcontroller. The execution time of EKF estimator was reduced from 260.4 μs to 37.7 μs without loss of accuracy. To further reduce EKF execution time, the separation of a Kalman gain and covariance matrices calculation from prediction and measurement state update, a novel method was proposed, and the performance of it an EKF estimator with separation of a Kalman gain and covariance matrices calculation from prediction and measurement state update was analyzed. Simulation and experiments results validate that the proposed technique could provide the same accuracy with less computation time. A tendency of minimum Kalman gain and covariance matrices calculation frequency from rotor electrical frequency was analyzed and are presented in the paper.

  • Implementation of Haar wavelet, higher order Haar wavelet, and differential quadrature methods on buckling response of strain gradient nonlocal beam embedded in an elastic medium
    • Subrat Kumar Jena
    • S. Chakraverty
    • Mohammad Malikan
    2021 Pełny tekst ENGINEERING WITH COMPUTERS

    The present investigation is focused on the buckling behavior of strain gradient nonlocal beam embedded in Winkler elastic foundation. The first-order strain gradient model has been combined with the Euler–Bernoulli beam theory to formulate the proposed model using Hamilton’s principle. Three numerically efficient methods, namely Haar wavelet method (HWM), higher order Haar wavelet method (HOHWM), and differential quadrature method (DQM) are employed to analyze the buckling characteristics of the strain gradient nonlocal beam. The impacts of several parameters such as nonlocal parameter, strain gradient parameter, and Winkler modulus parameter on critical buckling loads are studied effectively. The basic ideas of the numerical methods, viz. HWM, HOHWM, and DQM are presented comprehensively. Also, a comparative study has been conducted to explore the effectiveness and applicability of all the three numerical methods in terms of convergence study. Finally, the results, obtained by this investigation, are validated properly with other works published earlier.

  • Implementation of International Standards of Fiscal and Monetary Transparency - Case of Poland
    • Maria Jastrzębska
    2021

    Research background: Financial managers, investors, lenders, counterparties and citizens should have useful, reliable, timely, complete, comparable, readable information on fiscal and monetary policy. The actions taken and instruments used by fiscal and monetary authorities have an important impact on economic conditions. Purpose of the article: The aim of the article is to assess Poland's compliance with international standards of fiscal transparency and central bank transparency. Research methods: qualitative and descriptive analysis and inductive, deductive reasoning were applied. Findings: Raising the level of fiscal and monetary transparency is supported by compliance with international standards. In Poland, the level of monetary transparency is higher than that of fiscal transparency, with a lack of transparent information about the effects of unconventional state financial policy instruments on the economy and society.

  • Implementation of Non-Probabilistic Methods for Stability Analysis of Nonlocal Beam with Structural Uncertainties
    • Subrat Kumar Subrat
    • S. Chakraverty
    • Mohammad Malikan
    2021 Pełny tekst ENGINEERING WITH COMPUTERS

    In this study, a non-probabilistic approach based Navier’s Method (NM) and Galerkin Weighted Residual Method (GWRM) in term of double parametric form has been proposed to investigate the buckling behavior of Euler-Bernoulli nonlocal beam under the framework of the Eringen's nonlocal elasticity theory, considering the structural parameters as imprecise or uncertain. The uncertainties in Young’s modulus and diameter of the beam are modeled in terms of Triangular Fuzzy Numbers (TFN). The critical buckling loads are calculated for Hinged-Hinged (HH), Clamped-Hinged (CH), and Clamped-Clamped (CC) boundary conditions and these results are compared with the deterministic model in special cases, demonstrating robust agreement. Further, a random sampling technique based method namely, Monte Carlo Simulation Technique (MCST) has been implemented to compute the critical buckling loads of uncertain systems. Also, the critical buckling loads obtained from the uncertain model in terms of Lower Bound (LB) and Upper Bound (UB) by the non-probabilistic methods, viz. Navier’s Method (NM) and Galerkin Weighted Residual Method (GWRM), are again verified with the Monte Carlo Simulation Technique (MCST) with their time periods, demonstrating the efficacy, accuracy, and effectiveness of the proposed uncertain model. A comparative study is also carried out among the non-probabilistic methods and Monte Carlo Simulation Technique (MCST) to demonstrate the effectiveness of methods with respect to time. Additionally, a parametric study has been performed to display the propagation of uncertainties into the nonlocal system in the form of critical buckling loads.

  • Implementation of SiN thin film in fiber-optic sensor working in telecommunication range of wavelengths
    • Sandra Pawłowska
    • Jakub Gierowski
    • Bartłomiej Stonio
    • Marcin Juchniewicz
    • Mateusz Ficek
    • Michał Kruczkowski
    • Małgorzata Szczerska
    2021 Pełny tekst Scientific Reports

    Mirrors are used in optical sensors and measurement setups. This creates a demand for mirrors made of new materials and having various properties tailored to specific applications. In this work, we propose silicon covered with a thin silicon nitride layer as a mirror for near-infrared measurements. SiN layer was deposited on a standard silicon wafer with a Low-Pressure Chemical Vapor Deposition furnace. Then, the created layer was investigated using ellipsometry and scanning electron microscope. Subsequently, the mirror was used as a reflecting surface in a Fabry–Perot fiber-optic interferometer. The mirror performance was investigated for wavelengths used in telecomunication (1310 nm and 1550 nm) and then compared with results obtained with the same measurement setup, with a silver mirror instead of silicon covered with SiN, as reference. Results showed that the proposed mirror can replace the silver one with satisfying results for investigated wavelengths.

  • Implementation of the Concept of Flexicurity in the Selected Countries of Central Eastern Europe
    • Dagmara Nikulin
    • Małgorzata Gawrycka
    2021 Ekonomista

    The CEE countries have to create their own flexicurity policies which would take into account the employment policy guidelines, cultural traditions and socio-economic development. The aim of this article is to examine and evaluate the implementation of the flexicurity concept on the basis of the adopted set of composite indicators. The study covers 9 countries of the CEE region, and the research period covers the years 2007 and 2013. A review of previous research has demonstrated that there are no studies which would take into account a wide range of indicators included in the composite index of flexicurity. Moreover, in the case of CEE countries there is a lack of publications which would compare the degree of flexibility and security of their labour markets or studies that would compare flexicurity indicators for two different moments in time. This article tries to fill this research gap. The analysis of a composite indicator of flexicurity and its component elements shows large differences in the implementation of the flexicurity concept in the individual CEE countries. The labour market in the CEE countries is still characterized by high strictness of Employment Protection Legislation, which adversely affects the outcomes of the labour market. On the other hand, CEE countries have made great efforts in increasing the role of active labour market policies and non-standard forms of work in the last decade. In most of the countries studied the problem is still related to a relatively small share of individuals engaged in life-long learning and to ensuring the security of those working on non-standard employment contracts.

  • Importance of Bile Composition for Diagnosis of Biliary Obstructions
    • Łukasz Krupa
    • Robert Staroń
    • Dorota Dulko
    • Natalia Łozińska
    • Alan Mackie
    • Neil Rigby
    • Adam Macierzanka
    • Aleksandra Markiewicz
    • Christian Jungnickel
    2021 Pełny tekst MOLECULES

    Determination of the cause of a biliary obstruction is often inconclusive from serum analysis alone without further clinical tests. To this end, serum markers as well as the composition of bile of 74 patients with biliary obstructions were determined to improve the diagnoses. The samples were collected from the patients during an endoscopic retrograde cholangiopancreatography (ERCP). The concentration of eight bile salts, specifically sodium cholate, sodium glycocholate, sodium taurocholate, sodium glycodeoxycholate, sodium chenodeoxycholate, sodium glycochenodeoxycholate, sodium taurodeoxycholate, and sodium taurochenodeoxycholate as well as bile cholesterol were determined by HPLC-MS. Serum alanine aminotransferase (ALT), aspartate transaminase (AST), and bilirubin were measured before the ERCP. The aim was to determine a diagnostic factor and gain insights into the influence of serum bilirubin as well as bile salts on diseases. Ratios of conjugated/unconjugated, primary/secondary, and taurine/glycine conjugated bile salts were determined to facilitate the comparison to literature data. Receiver operating characteristic (ROC) curves were determined, and the cut-off values were calculated by determining the point closest to (0,1). It was found that serum bilirubin was a good indicator of the type of biliary obstruction; it was able to differentiate between benign obstructions such as choledocholithiasis (at the concentration of >11 µmol/L) and malignant changes such as pancreatic neoplasms or cholangiocarcinoma (at the concentration of >59 µmol/L). In addition, it was shown that conjugated/unconjugated bile salts confirm the presence of an obstruction. With lower levels of conjugated/unconjugated bile salts the possibility for inflammation and, thus, neoplasms increase.

  • Importance of Conjugation of the Bile Salt on the Mechanism of Lipolysis
    • Natalia Łozińska
    • Christian Jungnickel
    2021 Pełny tekst MOLECULES

    We aim to advance the discussion on the significance of the conjugation of bile salts (BS) in our organism. We hypothesize that conjugation influences the rate of lipolysis. Since the rate of lipolysis is a compound parameter, we compare the effect of conjugation on four surface parameters, which contribute to the rate. Since deconjugation is due to gut microbiota, we hypothesize that microbiota may affect the rate of lipolysis. A meta-analysis of literature data of critical micelle concentration, β, aggregation number, and molar solubilization ratio has been performed for the first time. In addition, critical micelle concentration (CMC), interfacial tension, and lipolysis rate measurements were performed. It was found that the unconjugated BS in mixed micelles increases the antagonism between the BS, therefore, increasing the CMC. This correlated with the effect of unconjugated BS on the solubilization capacity of mixed micelles. The collected literature information indicates that the role of the BS and its conjugation in our organism is a key factor influencing the functioning of our organism, where too high levels of unconjugated BS may lead to malabsorption of fat-soluble nutrients. The experimental lipolysis results irrevocably showed that conjugation is a significant factor influencing the rate.

  • Improved Design Closure of Compact Microwave Circuits by Means of Performance Requirement Adaptation
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Leifur Leifsson
    2021

    Numerical optimization procedures have been widely used in the design of microwave components and systems. Most often, optimization algorithms are applied at the later stages of the design process to tune the geometry and/or material parameter values. To ensure sufficient accuracy, parameter adjustment is realized at the level of full-wave electromagnetic (EM) analysis, which creates perhaps the most important bottleneck due to the entailed computational expenses. The cost issue hinders utilization of global search procedures, whereas local routines often fail when the initial design is of insufficient quality, especially in terms of the relationships between the current and the target operating frequencies. This paper proposes a procedure for automated adaptation of the performance requirements, which aims at improving the reliability of the parameter tuning process in the challenging situations as described above. The procedure temporarily relaxes the requirements to ensure that the existing solution can be improved, and gradually tightens them when close to terminating the optimization process. The amount and the timing of specification adjustment is governed by evaluating the design quality at the current design, and the convergence status of the algorithm. The proposed framework is validated using two examples of microstrip components (a coupler and a power divider), and shown to well handle design scenarios that turn infeasible for conventional approaches, in particular, when decent starting points are unavailable.

  • Improved Modeling of Microwave Structures Using Performance-Driven Fully-Connected Regression Surrogate
    • Sławomir Kozieł
    • Peyman Mahouti
    • Nurullah Calik
    • Mehmet Belen
    • Stanisław Szczepański
    2021 Pełny tekst IEEE Access

    Fast replacement models (or surrogates) have been widely applied in the recent years to accelerate simulation-driven design procedures in microwave engineering. The fundamental reason is a considerable—and often prohibitive—CPU cost of massive full-wave electromagnetic (EM) analyses related to solving common tasks such as parametric optimization or uncertainty quantification. The most popular class of surrogates are data-driven models, which are fast to evaluate, versatile, and easy to handle. Notwithstanding, the curse of dimensionality as well as the utility demands (e.g., so that the model covers sufficiently broad ranges of the system operating conditions), limit the applicability of conventional methods. A performance-driven modeling paradigm allows for mitigating these issue by focusing the surrogate setup process in a constrained domain encapsulating designs being of high quality w.r.t. the assumed figures of interest. The nested kriging framework capitalizing on this idea, renders the constrained surrogate using kriging interpolation, and has been shown to surpass traditional approaches. In pursuit of further accuracy improvements, this work incorporates the performance-driven concept into the fully-connected regression model (FRCM). The latter has been recently introduced in the context of frequency selective surfaces, and combined deep neural networks with Bayesian optimization, the latter employed to determine the network architecture and hyper-parameters. Using two examples of miniaturized microstrip couplers, our methodology is demonstrated to outperform both conventional modeling techniques and nested kriging, with reliable models constructed over multi-dimensional parameters spaces using just a few hundreds of samples.

  • Improvement of Oxygen Electrode Performance of Intermediate Temperature Solid Oxide Cells by Spray Pyrolysis Deposited Active Layers
    • Bartosz Kamecki
    • Jakub Karczewski
    • Piotr Jasiński
    • Sebastian Molin
    2021 Advanced Materials Interfaces

    Intermediate temperature solid oxide fuel cells oxygen electrodes are modified by active interfacial layers. Spray pyrolysis is used to produce thin (≈500 nm) layers of mixed ionic and electronic conductors: Sm0.5Sr0.5CoO3−δ (SSC), La0.6Sr0.4CoO3−δ (LSC), La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF), and Pr6O11 (PrOx) on the electrode–electrolyte interface. The influence of the annealing temperature on the electrode polarization (area specific resistance—ASRpol) is investigated by impedance spectroscopy of symmetrical electrodes in the temperature range of 400–700 °C. The results show that the introduction of nanocrystalline interlayers promotes an oxygen reduction reaction by extending the active surface area and improved contact between the electrode and the electrolyte. Introducing LSCF, LSC, or SSC interlayer reduces ASRpol by a factor of 4 and PrOx by a factor of 2 against the reference, powder processed LSCF electrode. At 600 °C, the obtained ASRpol values for PrOx, LSCF, LSC, and SSC interlayer are 245, 137, 119, and 107 mΩ cm2, which can be considered very low in comparison to standard powder processed oxygen electrodes. Anode supported single cell with developed LSC/LSCF electrode reveals ≈1.2 W cm−2 power output at 600 °C and maintains stable cell voltage of 0.75 V under 1 A cm−2 during 60 h of the test.

  • Improvement of the Chimney Effect in Stack Ventilation
    • Romana Antczak-Jarząbska
    • Krzysztof Pawłowski
    • Maciej Niedostatkiewicz
    2021 Pełny tekst Applied Sciences-Basel

    The article is focused on the airflow in a ventilation system in a building. The work examines the methods which enhance the chimney effect. In this paper, three cases with different chimneys were analyzed for the full-scale experiment. These cases were characterized by different geometrical and material parameters, leading to differences in the intensity of the ventilation airflow. The common denominator of the cases was the room with the air inlet and outlet to the ventilation system. The differences between the experimental cases concerned the chimney canal itself, and more precisely its part protruding above the roof slope. The first experimental case concerned a ventilation canal made in a traditional way, from solid ceramic brick. The second experimental case concerned the part that led out above the roof slope with a transparent barrier, called a solar chimney. In the third experimental case, a rotary type of chimney cap was installed on the chimney to improve the efficiency of stack ventilation. All these cases were used to determine the performance of natural ventilation—Air Change per Hour (CH). Additionally, the paper presents a technical and economic comparison of the solutions used.

  • Improvements and Spatial Dependencies in Energy Transition Measures
    • Marta Kuc-Czarnecka
    • Magdalena Olczyk
    • Marek Zinecker
    2021 Pełny tekst ENERGIES

    This article aims to improve one of the newest energy transition measures—the WorldEconomic Forum WEF Energy Transition Index (ETI) and find its driving forces. This paper proposesa new approach to correct the ETI structure, i.e., sensitivity analysis, which allows assessing theaccuracy of variable weights. Moreover, the novelty of the paper is the use the spatial error modelsto estimate determinants of the energy transition on different continents. The results show thatETI is unbalanced and includes many variables of marginal importance for the shape of the finalranking. The variables with the highest weights in ETI did not turn out to be its most importantdeterminants, which means that they differentiate the analysed countries well; nonetheless, theydo not have sufficient properties of approximating the values of the ETI components. The mostimportant components of ETI (with the highest information load) belong to the CO2emissions percapita, the innovative business environment, household electricity prices, or renewable capacitybuildout. Moreover, we identified the clustering of both ETI and its two main pillars in Europe, whichis not observed in America and Asia. The identified positive spatial effects showing that Europeancountries need much deeper cooperation to reach a successful energy transitio

  • Improvements to the STEAM-based teaching of architectural drawing
    • Mateusz Gerigk
    2021 Pełny tekst World Transactions on Engineering and Technology Education

    The author of this article presents a systemic approach to improving the teaching of architectural drawing courses for engineers in the 21st Century. In this era of rapid development of digital technologies, the traditional teaching structure should be redefined to a purpose-oriented dynamic model. The existing, generally accepted teaching models have already proved successfully based on the practice-oriented STEAM programme, which integrates science, technology, engineering, art and mathematics. The systemic approach proposed in the article is a step forward in the teaching model strongly focusing on the open structure of the model necessary for its future development in this changing environment. The usefulness of the proposed model for the improvement of teaching architectural drawing has been analysed along with the syllabus of the Architectural Drawing course in the Faculty of Architecture at Gdańsk University of Technology, Gdańsk, Poland. The results of on-line teaching during the Covid-19 pandemic restrictions were processed by data analysis. The usefulness of the proposed model in different areas of engineering education is discussed in this article.

  • Improving Accuracy of Respiratory Rate Estimation by Restoring High Resolution Features With Transformers and Recursive Convolutional Models
    • Alicja Kwaśniewska
    • Maciej Szankin
    • Jacek Rumiński
    • Anthony Sarah
    • David Gamba
    2021 Pełny tekst

    Non-contact evaluation of vital signs has been becoming increasingly important, especially in light of the COVID- 19 pandemic, which is causing the whole world to examine people’s interactions in public places at a scale never seen before. However, evaluating one’s vital signs can be a relatively complex procedure, which requires both time and physical contact between examiner and examinee. These re- quirements limit the number of people who can be efficiently checked, either due to the medical station throughput, pa- tients’ remote locations or the need for social distancing. This study is a first step to increasing the accuracy of com- puter vision-based respiratory rate estimation by transfer- ring texture information from images acquired in different domains. Experiments conducted with two deep neural net- work topologies, a recursive convolutional model and trans- formers, proved their robustness in the analyzed scenario by reducing estimation error by 50% compared to low resolu- tion sequences. All resources used in this research, including links to the dataset and code, have been made publicly available.

  • Improving Clairvoyant: reduction algorithm resilient to imbalanced process arrival patterns
    • Jerzy Proficz
    • Krzysztof Ocetkiewicz
    2021 Pełny tekst JOURNAL OF SUPERCOMPUTING

    The Clairvoyant algorithm proposed in “A novel MPI reduction algorithm resilient to imbalances in process arrival times” was analyzed, commented and improved. The comments concern handling certain edge cases in the original pseudocode and description, i.e., adding another state of a process, improved cache friendliness more precise complexity estimations and some other issues improving the robustness of the algorithm implementation. The proposed improvements include skipping of idle loop rounds, simplifying generation of the ready set and management of the state array and an about 90-fold reduction in memory usage. Finally an extension enabling process arrival times (PATs) prediction was added: an additional background thread used to exchange the data with the PAT estimations. The performed tests, with a dedicated mini-benchmark executed in an HPC environment, showed correctness and improved performance of the solution, with comparison to the original or other state-of-the-art algorithms.

  • Improving methods to calculate the loss of ecosystem services provided by urban trees using LiDAR and aerial orthophotos
    • Karolina Zięba-kulawik
    • Paweł Hawryło
    • Piotr Wężyk
    • Piotr Matczak
    • Patrycja Przewoźna
    • Adam Inglot
    • Krzysztof Mączka
    2021 URBAN FORESTRY & URBAN GREENING

    In this paper we propose a methodology for combining remotely sensed data with field measurements to assess selected tree parameters (diameter at breast height (DBH) and tree species) required by the i-Tree Eco model to estimate ecosystem services (ES) provided by urban trees. We determined values of ES provided by trees in 2017 in Racibórz (a city in South Poland) and estimated the loss of ES from January 1, 2017 to March 5, 2017, a period of changing legislation that temporarily allowed removal of trees on private property without any permission from city authorities. We applied Canopy Height Models (CHM; GSD 1.0 m) generated from two sets of ALS LiDAR point clouds (acquisitions on June 11, 2011 and March 5, 2017) and performed tree crown segmentations using the GEOBIA approach. Physical attributes were estimated for each tree using predictive models, developed based on field tree inventory . The reference areas for parameterizing the segmentation algorithm and assessing tree species composition were established in Racibórz, while reference data required for assessment of DBH were obtained from the MONIT-AIR project (from Municipality of Kraków). We found that in 2017, 988.79 ha of Racibórz (13.2 % of city area) was covered by the crowns of 264 471 trees, providing ES structural values worth over 384 mil €. The structural value of ES lost in the first months of 2017 (during which 5 075 trees were removed) was about 3.5 mil €. We concluded that in the face of information on tree crown cover that is often missing from city databases, tree inventories require application of a combination of multi-source and multi-resolution spatial analyses, including: administrative decisions for tree removal with exact location, predictive modelling of selected biometrical tree information, automatic crown segmentation on CHM and interpretation of regularly updated color infrared (CIR) aerial orthophotos.

  • Improving social competencies of architecture students through participatory design of marketplace regeneration
    • Justyna Borucka
    • Piotr Czyż
    • Weronika Mazurkiewicz
    • Łukasz Pancewicz
    • Iga Perzyna
    2021 Pełny tekst World Transactions on Engineering and Technology Education

    The article discusses the involvement of architecture students in actual urban regeneration projects through participatory design and tray to respond question how it can improve students social competences, and benefit their future careers as architects and urban planners. By using the example of the student workshops conducted in 2019 at the Faculty of Architecture, GdanskTech, the article discusses the specific methods applied in the participatory process and their impact on the improvement of the social competence of students and the educational benefits of using this methodology in university courses. The student workshops were linked to an ongoing project concerned with regeneration of urban markets across Poland, conducted within the framework of the GOSPOSTRATEG program financed by the National Centre for Research and Development in Poland. Real-life experience of students during participation in enterprises like presented seems to be crucial at attaining high level of social competences. This is even more important in the context of the changing role of the architectural profession in the contemporary complex reality.

  • Improving the regulation of the derivatives market as an objective prerequisite for sustainable development of the global financial system
    • Oksana Novak
    • Oleksandr Melnychenko
    • Oksana Oliinyk
    2021 Pełny tekst E3S Web of Conferences

    The development of financial markets is characterized by the emergence of new financial instruments, in particular derivatives, the risk level analysis of which is complicated. Counterparties are not always fully aware of and do not adequately assess the potential risks of derivatives, which may lead to large financial losses and sometimes bankruptcies. The purpose of the study is to generalize approaches to regulating derivative markets and analyse the adequacy of regulatory influence to ensure sustainable development of the global financial system. The article analyses the approaches of scientists and regulators of the USA and the EU to the regulation of the derivatives market before and after the financial crisis of 2007-2008. Prior to the crisis, most scholars took a liberal approach to derivatives market regulation and recommended monitoring new instruments and not restricting their circulation in any way, emphasizing that effective counterparty risk management and their propensity for self-preservation can prevent excessive risk-taking. The authors analyse the potential risks of derivatives and conclude that exchange-traded derivatives can cause similar processes of liquidity crisis, and, therefore, need additional regulatory tools to ensure the stability of the financial system

  • In Search for Answers: Light4Health Online Course of Health Research for Interior Lighting Design
    • Karolina Zielińska-Dąbkowska
    2021 Pełny tekst ARC Lighting In Architecture

    Three years ago, when I wrote an article in arc called: Human Centric Lighting. The New X Factor? (arc no. 108 Feb/Mar 2019), my intention was to raise questions in relation to the new topic and to find solid, research-based answers in the years to come. Today, I am happy to report that the lighting community, with the Light4Health Online Course of Health Research for Interior Lighting Design, has a useful tool, and consortium members have managed to close the gap between research and practice/application, and translate complex research into an ‘easy to digest’ format for end users.

  • In silico assessment and sonochemical synthesis of 2-alkynyl 3-chloropyrazines as prospective ligands for SARS-CoV-2
    • M.v. Satyanarayana
    • Alugubelli Gopi Reddy
    • M. Yedukondalu
    • Mandava Bhuvan Tej
    • Kazi Hossain
    • Mandava Venkata Basaveswara Rao
    • Manojit Pal
    2021 Pełny tekst JOURNAL OF MOLECULAR STRUCTURE

    The recent global pandemic caused by COVID-19 has triggered an intense effort worldwide towards the development of an effective cure for this disease. In our effort we have explored the 2-alkynyl substituted 3-chloropyrazine framework as a potential template for the design of molecules for this purpose. Our strategy was supported by the in silico studies of representative compounds to assess their binding affinities via docking into the N-terminal RNA-binding domain (NTD) of N-protein of SARS-CoV-2. Thus we created a small library of molecules based on the aforementioned template via an environmentally safer method that involved the rapid synthesis of 2-alkynyl 3-chloropyrazine derivatives under Cu-catalysis assisted by ultrasound. The reactions proceeded via the coupling of 2,3-dichloropyrazine with commercially available terminal alkynes in the presence of CuI, PPh3 and K2CO3 in PEG-400. Further molecular modelling studies helped in establishing a virtual SAR (Structure Activity Relationship) within the series and identification of three potential hits. The desirable ADME was also predicted for these three molecules suggesting their prospective medicinal value.

  • In Vitro Dissolution of Na-Ca-P-Oxynitrides
    • Natalia Wójcik
    • Polina Sinitsyna
    • Sharafat Ali
    • Leena Hupa
    • Bo Jonson
    2021 Pełny tekst Materials

    : Sodium-calcium-phosphate based oxynitride glasses and glass-ceramics doped with Mg, Si, and Nb were studied in vitro in simulated body fluid (SBF) under static conditions. The release of ions and pH changes up to 7 days of immersion were investigated. The nitrogen incorporation into phosphate glass matrix was found to notably influence in vitro dissolution only of homogenous glasses. Increasing the nitrogen content in the samples decreased the mean mass loss, while the niobate incorporation increased it. The correlation between the nitrogen content and increase in pH of SBF was also observed. The presence of phosphates crystallites was found to support the dissolution process at the beginning step (up to 3 days).

  • Inception and Propagation of Electrical Trees in the Presence of Space Charge in HVAC Extruded Cables
    • Mohammad AlShaikh Saleh
    • Shady S. Refaat
    • Marek Olesz
    • Haitham Abu-Rub
    2021 IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION

    This paper presents the space charge impact on the inception and propagation of electrical trees in cross-linked polyethylene (XLPE) insulation via simulations and experimentation. A 3D finite element analysis (FEA)-based modeling is proposed to simulate electrical trees via a needle embedded on the XLPE insulation. The proposed FEA model demonstrates the influence of the space charge magnitude and polarity on the initiation of partial discharges (PD). Then the critical parameters at the tip of an 8 tree are to be examined. Experimentation is necessary to verify the simulation results acquired and study the mechanism of electrical trees at the inception and propagation stage. Therefore, in the experiment, a needle with a curvature radius of 5 is embedded in the XLPE as a method of simulating defects, such as protrusions, voids, or cracks found in cable insulation. The power source supplies several high AC voltages on the 20 kV (rated voltage) cable under test for observing the inception and propagation behavior of the electrical trees. Phase-resolved partial discharge (PRPD) patterns are extracted at the inception and propagation stages of the electrical tree to determine the severity of the PDs occurring. A relationship is obtained for the PD magnitude with respect to the applied AC voltage while considering the positive and negative polarities of the PDs. This relationship then allows for the acquisition of the maximum electric field-tree length characteristics. The goal of the simulation of electrical trees is to provide the reader with a better understanding about the effect of space charge magnitude and polarity to comprehend the behavior of the treeing inception and propagation mechanisms. The injection and extraction of space charges is a complex phenomenon that requires further visualization through simulations. Therefore, the results of both the simulation and experiment are compared with the aim of establishing a clear relationship between space charge distribution and tree initiation.

  • Inclusive Communication Model Supporting the Employment Cycle of Individuals with Autism Spectrum Disorders
    • Michał Tomczak
    • Joanna Maria Szulc
    • Małgorzata Szczerska
    2021 Pełny tekst International Journal of Environmental Research and Public Health

    Difficulties with interpersonal communication experienced by individuals with autism spectrum disorders (ASD) significantly contribute to their underrepresentation in the workforce as well as problems experienced while in employment. Consistently, it is vital to understand how communication within the employment cycle of this group can be improved. This study aims to identify and analyze the possibilities of modifying the communication processes around recruitment, selection, onboarding, and job retention to address the specific characteristics and needs of the representatives of this group. This qualitative study is based on 15 in-depth interviews conducted with 21 field experts, i.e.,: therapists, job trainers, and entrepreneurs employing people with ASD. The findings of this research informed the creation of an inclusive communication model supporting the employment cycle of individuals with ASD. The most important recommendations within the model that was created include the modification of job advertisements, use of less structured job interviews, providing opportunities for mentorship, and supportive and non-direct, electronically mediated communication. To apply the above-mentioned solutions and take full advantage of the talents of people with ASD, it is also necessary to provide tailored sensitivity and awareness training programs for their direct addressees as well as their neurotypical colleagues, including managerial staff.

  • Incorporation of nitrogen in diamond films – A new way of tuning parameters for optical passive elements
    • Monika Kosowska
    • Sandra Pawłowska
    • Kamatchi J Sankaran
    • Daria Majchrowicz
    • Ken Haenen
    • Kishan Dholakia
    • Małgorzata Szczerska
    2021 DIAMOND AND RELATED MATERIALS

    This paper investigates the impact of nitrogen incorporation in diamond films for the construction of an interferometric sensor to measure displacement. Diamond films with different nitrogen levels (0–5%) were deposited on silicon substrates by microwave plasma enhanced chemical vapor deposition. The structural characteristics of these samples are characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), confocal micro-Raman spectroscopy, and electron energy loss spectroscopy (EELS). The homogeneous and continuous surface morphology of the films is observed through SEM. In the micro-Raman and electron energy loss spectroscopy studies, it is evident that there is a formation of sp2 -bonded carbon phases due to the increase in the concentration of nitrogen. This investigation gives a strong basis for utilizing these diamond films as reflective layers in fiber-optic devices. The interferometric measurement setup is constructed as a Fabry-P´erot interferometer. The nitrogen incorporated films are proved to be useful as mirrors as they achieve a measurement signal with high contrast. The achieved visibility values for the investigated samples are higher than 94% in the range of 40–100 μm.

  • Incorporation of the complete ammonia oxidation (comammox) process for modeling nitrification in suspended growth wastewater treatment systems
    • Mohammad Javad Mehrani
    • Lu Xi
    • Przemysław Kowal
    • Dominika Sobotka
    • Jacek Mąkinia
    2021 Pełny tekst JOURNAL OF ENVIRONMENTAL MANAGEMENT

    The newly discovered process complete ammonia oxidation (comammox) has changed the traditional under-standing of nitrification. In this study, three possible concepts of comammox were developed and incorporated as part of an extended two-step nitrification model. For model calibration and validation, two series of long-term biomass washout experiments were carried out at 12 ◦C and 20 ◦C in a laboratory sequencing batch reactor. The inoculum biomass was withdrawn from a large biological nutrient removal wastewater treatment plant. The efficiency of the examined models was compared based on the behaviors of ammonia, nitrite, and nitrate in the studied reactor. Predictions of the conventional approach to comammox, assuming the direct oxidation of ammonia to nitrate, were slightly better than the two other approaches. Simulation results revealed that comammox could be responsible for the conversion of >20% of the influent ammonia load. Therefore, the role of commamox in the nitrogen mass balance in activated sludge systems should not be neglected and requires further investigation. Furthermore, sensitivity and correlation analysis revealed that the maximum growth rates (μ), oxygen half-saturation (KO), and decay rates (b) of the canonical nitrifiers and comammox were the most sen-sitive factors, and the highest correlation was found between μ and b among all considered kinetic parameters. The estimated μ values by the best model were 0.57, 0.11, and 0.15 d.

  • Independent Domination Subdivision in Graphs
    • Ammar Babikir
    • Magda Dettlaff
    • Michael A. Henning
    • Magdalena Lemańska
    2021 Pełny tekst GRAPHS AND COMBINATORICS

    A set $S$ of vertices in a graph $G$ is a dominating set if every vertex not in $S$ is adjacent to a vertex in~$S$. If, in addition, $S$ is an independent set, then $S$ is an independent dominating set. The independent domination number $i(G)$ of $G$ is the minimum cardinality of an independent dominating set in $G$. The independent domination subdivision number $\sdi(G)$ is the minimum number of edges that must be subdivided (each edge in $G$ can be subdivided at most once) in order to increase the independent domination number. We show that for every connected graph $G$ on at least three vertices, the parameter $\sdi(G)$ is well defined and differs significantly from the well-studied domination subdivision number $\sdg(G)$. For example, if $G$ is a block graph, then $\sdg(G) \le 3$, while $\sdi(G)$ can be arbitrary large. Further we show that there exist connected graph $G$ with arbitrarily large maximum degree~$\Delta(G)$ such that $\sdi(G) \ge 3 \Delta(G) - 2$, in contrast to the known result that $\sdg(G) \le 2 \Delta(G) - 1$ always holds. Among other results, we present a simple characterization of trees $T$ with $\sdi(T) = 1$.

  • Independent dynamics of low, intermediate, and high frequency spectral intracranial EEG activities during human memory formation
    • Victoria Marks
    • Krishnakant Saboo
    • Çağdaş Topçu
    • Michał Lech
    • Theodore Thayib
    • Petr Nejedly
    • Vaclav Kremen
    • Gregory A. Worrell
    • Michał Kucewicz
    2021 Pełny tekst NEUROIMAGE

    A wide spectrum of brain rhythms are engaged throughout the human cortex in cognitive functions. How the rhythms of various frequency ranges are coordinated across the space of the human cortex and time of memory processing is inconclusive. They can either be coordinated together across the frequency spectrum at the same cortical site and time or induced independently in particular bands. We used a large dataset of human intracranial electroencephalography (iEEG) to parse the spatiotemporal dynamics of spectral activities induced during formation of verbal memories. Encoding of words for subsequent free recall activated low frequency theta, intermediate frequency alpha and beta, and high frequency gamma power in a mosaic pattern of discrete cortical sites. A majority of the cortical sites recorded activity in only one of these frequencies, except for the visual cortex where spectral power was induced across multiple bands. Each frequency band showed characteristic dynamics of the induced power specific to cortical area and hemisphere. The power of the low, intermediate, and high frequency activities propagated in independent sequences across the visual, temporal and prefrontal cortical areas throughout subsequent phases of memory encoding. Our results provide a holistic, simplified model of the spectral activities engaged in the formation of human memory, suggesting an anatomically and temporally distributed mosaic of coordinated brain rhythms.

  • Indoor accelerated controlled corrosion degradation test of small- and large-scale specimens
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    • Jakub Kowalski
    2021 Pełny tekst OCEAN ENGINEERING

    The work presented here is a part of a long-term project analysing the structural behaviour of ageing marine structures. An accelerated corrosion degradation set-up was developed to reproduce corroded marine structural specimens of different degrees of degradation, controlling various natural factors, i.e., temperature, oxygen content, salinity, and flow velocity. The nine stiffened plates of 1.2 m length and 30 small scale specimens made of mild steel of three different thicknesses have been corroded. The mean corrosion depth and rate have been controlled during the degradation process for all specimens. The corrosion degradation characteristics have been measured and analysed. In the case of small-scale specimens, microscope scanning, and for the stiffened plates, ultrasonic thickness measurements were performed. The obtained corrosion surfaces are highly non-uniform. During the corrosion degradation, a number of measurements were performed to satisfy a confidence level of 95% and an error of 10%. The developed corrosion degradation is compared with a real corrosion depth measurement of ship deck plates of ballast and cargo tanks, showing a very good similarity in the trend and the corrosion acceleration, concluding that the developed corrosion degradation controlled experimental set-up is efficient in reproducing marine structural specimens of different degree of degradation for further mechanical testing.

  • Induction Assisted Hybrid Friction Stir Welding of Dissimilar Materials AA5052 Aluminium Alloy and X12Cr13 Stainless Steel
    • Dhanesh G. Mohan
    • Jacek Tomków
    • S Gopi
    2021 Pełny tekst Advances in Materials Science

    This research aimed to study the induction in-situ heated hybrid friction stir welding (IAFSW) method to join AA5052 aluminium alloy with X12Cr13 stainless steel (SS) to enhance joint strength. The potency of this method on the mechanical properties and microstructural characterizations were also investigated. The results show that the transverse tensile strength gained was 94% of the AA5052 base metal that is 229.5 MPa. This superior strength was achieved due to the annealing that happened to the AA 5052 region and elevated plastic flow in the weld zone by the in-situ induction heating, which resulted in the elongation of the weld region. The microstructure characterization indicates that a refined grain structure was gained in the nugget zone without defects.

  • Influence of alkali metal cations on the photoactivity of crystalline and exfoliated amorphous WO3 – photointercalation phenomenon
    • Mariusz Szkoda
    • Konrad Trzciński
    • Grzegorz Trykowski
    • Marcin Łapiński
    • Anna Lisowska-Oleksiak
    2021 Pełny tekst APPLIED CATALYSIS B-ENVIRONMENTAL

    In order to investigate the effect of photointercalation on photoelectrochemical properties, two types of WO3-based photoanodes, bulk and exfoliated have been prepared and investigated. An aqueous exfoliation method is introduced for the simple fabrication of amorphous and hydrated WO3 nanomaterial using commercial bulk WO3 precursor. The comparison of obtained material with bulk WO3 was performed using Raman, UV–vis, and XPS as well as scanning and transmission electron microscopies. The photoelectrochemical and photocatalytic performances of bulk and exfoliated WO3 were compared. Generally, the proposed exfoliation procedure led to the preparation of photo(electro)catalyst characterized by better performance measured as a photocurrent of water oxidation and rate of methylene blue photodecomposition. The main aim of this research was to investigate the influence of alkali metal cations (Li+,Na+,K+,Cs+) presence in electrolyte on the photocatalytic and photo(electro)catalytic activity of the samples in a form of suspended powder and thin layer on transparent-conductive substrate (FTO), respectively.