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Gdańsk University of Technology

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  • The Prospects of Retail Payment Developments in the Metaverse
    • Oleksandr Melnychenko
    2021 Full text Virtual Economics

    In the age of technological development, rapid technological progress, and the metaverse development in which humans interact with each other and with the environment using virtual real-world metaphors, payment systems may also need to be re-considered. The study aims to find an answer to the question of what should be retail payments in the metaverse and to begin interdisciplinary discussions about their implementation in this environment. The author reviews the literature which shows that i) socio-economic relations are being implemented in the metaverse, but they still require the money to participate in the exchange relationships, as well as to support such a system; ii) it is impossible to abandon all forms of physical exchange, which is the basis of modern society; iii) the metaverse is an environment usually of anonymous users, who do not have the right to make significant purchases without their identification; iv) accounting of transactions remains the basis of payments in the metaverse as well

  • The protective properties of graphene oxide coatings functionalized with phosphorus atoms.
    • Karolina Grajewska
    • Marek Lieder
    2021

    Recently, electrophoretically deposited graphene oxide coatings are commonly applied as an anti-corrosion layer. However, improper adjustment of electrophoretic deposition (EPD) parameters as well as the hydrophilic nature of graphene oxide contribute to the formation of defects in the coatings and the increase in the wetting properties, respectively, and thus lead to a reduction of protective properties. The growth of wetting performance can be eliminated by a modification of graphene oxide with other chemical compounds. Phosphorus functionalized graphene oxide (P-rGO) coatings as anti-corrosion layers have not been reported yet. As a result of hydrothermal treatment in the presence of orthophosphoric acid, P-rGO samples were obtained. The formation of phosphorus precursors of coatings was confirmed by numerous structural studies. FTIR spectra indicated two peaks, which can be assigned to P-C and P-O bonds. The foreign atoms were introduced into graphene oxide structure in the content of 5%, which was proved based on XPS analysis. The stable and uniform suspension of precursors of coatings allows the production of coatings on the copper substrate by EPD. The uniform and hydrophobic surface of coatings enhanced the anti-corrosion performance compared to nonmodified graphene oxide coatings.

  • The Reactivity of the Imine Bond within Polynuclear Nickel(II) Complexes
    • Magdalena Siedzielnik
    • Dimitrios A. Pantazis
    • Jakub Bruniecki
    • Kinga Kaniewska-Laskowska
    • Anna Dołęga
    2021 Full text Crystals

    Three novel Ni complexes with the Schiff base ligand 2-methoxy-6-(E-2-pyridyliminomethyl)-phenol (L1) are described. In comparison with the similar 2-(pyridine-2-ylimino-methyl)phenol (pymp), the mode of coordination of L1 is altered due to the presence of methoxy substituent introducing the sterical hindrance. During the synthesis of the complexes, partial hydrolysis of the ligand was observed. Since such immediate hydrolysis of L1 was not detected during the reactions of Zn(II) and Cu(II) salts with L1, the DFT calculated structures of a series of similar Zn, Cu, Ni, and Co complexes with L1 are compared to account for the phenomenon

  • THE RISE OF FISCAL OPACITY IN POLAND IN THE ERA OF THE COVID-19 PANDEMIC
    • Maria Jastrzębska
    2021

    Research background: The quality of information provided by the fiscal authorities and the correct flow of this information between them and the society are very important especially in times of crisis, when there is an imbalance in public finances and an increasing public debt. Ensuring fiscal transparency (transparency of public finances) reduces fiscal risk and corruption and supports public acceptance of fiscal reforms. Purpose of the article: The aim of the article is to assess the transparency of public finances in Poland in the era of COVID-19 pandemic. Changes in the system of public finances, which cause an increase in the opacity of public finances, were analysed. It also recommends necessary actions to be taken in order to increase transparency of public finances. Research methods: Qualitative analysis, deductive and inductive reasoning were used. Findings and added value: Poland lacks a transparent message about public finances with a particular focus on the state budget, which would allow citizens to control the government's fiscal policy actions. In 2020, a number of solutions were introduced, which meant that a significant part of public expenditure is made outside the control of the parliament. In addition, a significant source of their financing is the issue of debt securities issued by the State Treasury, or guaranteed by the State Treasury. It is difficult to reliably assess the condition of public finances due to differences in the methodology of calculating the level of public sector deficit and debt in terms of national and EU legal regulations.

  • THE ROLE OF INFERENCE IN MOBILE MEDICAL APPLICATION DESIGN
    • Tomasz Kocejko
    2021

    In the early 21st century, artificial intelligence began to be used to process medical information. However, before this happened, predictive models used in healthcare could only consider a limited number of variables, and only in properly structured and organised medical data. Today, advanced tools based on machine learning techniques - which, using artificial neural networks, can explore extremely complex relationships - and deep learning technologies effectively support the user in performing parts of healthcare tasks, often resulting in better results that cannot be achieved by humans. AI systems are designed to cope with the complex data generated within modern healthcare. Although deep learning algorithms proved to provide reliable results on variety of data types most common algorithms performs best when applied on images. Therefor in this chapter, the step-by-step process of building the medical application that utilizes the neural network model for image based diagnosis is presented

  • THE ROLE OF THE STATE IN TAXATION. POLISH TAX POLICY AFTER 2015
    • Piotr Kasprzak
    2021

    This article is an attempt to present and evaluate tax policy Polish of the years 2015-2020, i.e. the period which resulted in formulating the new government. These time was a period of tax reforms, the introduction of new taxes and public tributes, as well as new mechanisms to control tax collection. Moreover, the policies introduced also concern changes in the level of fiscalism and tax redistribution. The research methods adopted in the paper include, in particular, the evaluation and analysis of secondary statistics, legal acts, literature review and specialized industry reports analyses.

  • The room above the porte cochere of the Kwidzyn castle in the times of Pomesanian chapter
    • Aleksander Piwek
    • Tomasz Jażdżewski
    2021 Full text Architectus

    Artykuł przedstawia historię budowlaną pomieszczenia nad przejazdem bramnym w skrzydle północnym zamku w Kwidzynie w czasach kapituły pomezańskiej. Prezentowane ustalenia uzyskano na podstawie wyników badań architektonicznych, stratygraficznych oraz analizy materiałów archiwalnych, które przeprowadzono w 2017 roku. Według nich pomieszczenie powstało w pierwszym etapie wznoszenia zamku. W kolejnych wiekach podlegało architektonicznym zmianom odpowiadającym nowym potrzebom mieszkańców zamku. Zachowane ślady świadczą, że od XIV do XVI wieku pełniło ono kilka następujących po sobie funkcji, dotąd nie w pełni rozpoznanych i umotywowanych: strażnicy, kancelarii bądź izby sądowej, a nawet kaplicy. Znaczną część wiedzy o nich zawarto w rozwarstwieniu ścian i rekonstrukcjach historycznych przekształceń z okresu średniowiecza. W późniejszych czasach wnętrze uniknęło znacznych zniszczeń i do dziś stanowi cenne źródło wiedzy o historii zamku.

  • The Self-employment of Women in Azerbaijan
    • Krystyna Gomółka
    2021 Full text STUDIA EUROPEJSKIE

    Azerbaijan has a population of more than 10 million, of which women accounted for 50% in 2020. At the same time, 93% of Azerbaijan’s citizens describe themselves as Muslims. Since the beginning of independence, Azerbaijan has been a secular state by virtue of Article 48 of the Constitution, which guarantees the freedom of worship, choice, or non-practice of religion and the freedom of expression of one’s own views on religion. This article aims to assess the changes in the self-employment of women in Azerbaijan through a deductive analysis of data and observation of changes in the structure of resources based on generally available macroeconomic data. This study focuses on the situation of women on the Azerbaijani labour market over the two decades of the 21st century. The numbers of economically active women, including those in employment and the unemployed, and economically inactive women are specifi ed. Further, the government’s legal and fi nancial policy in respect of women’s self-employment is analysed. The author determines what percentage of companies were set up by women and in which sectors and locations.

  • The share of investments in gold and oil using the example of selected European stock exchanges– A comparative analysis
    • Marcin Potrykus
    2021 Full text Cogent Economics & Finance

    In this article, optimal investment portfolios with minimal risk and maximum efficiency were calculated. The portfolios were designated for ten selected European stock exchanges, based on the listings of the twenty largest companies in each of those markets. All calculations were made based on company shares only, company shares and investments in gold, shares of companies and investments in crude oil as well as shares of companies and investments in gold and crude oil. The research hypothesis tested in the study is: The share of alternative investments in the investment portfolio does not depend on the stock exchange, but it differs depending on the length of the estimation window used. The study showed that for most exchanges there were statistically significant differences for the distribution of the determined weight for alternative investments. However, it was noted that the longer the estimation window, the greater the number of exchanges with no differences in the distributions of that weight. In addition, for portfolios with minimal risk, there were larger differences between the designated weights of alternative investments than for the same portfolios, which were determined based on maximizing efficiency. It was also found that the longer the estimation window, the higher the efficiency of the designated portfolios. Moreover, the investment in gold had an average weight, in four-element portfolios with a minimum risk, greater than 60%. Oil investment in the same portfolios had an average weight of 28%.

  • The Staged Combustion of Meat-and-Bone Meal:The Characteristics of Conversion Sub-processes and Large-Scale Process Outputs
    • Marcin Kantorek
    • Krzysztof Jesionek
    • Sylwia Polesek-Karczewska
    • Paweł Ziółkowski
    • Janusz Badur
    2021

    t Organic waste has been playing an increasingly important role in the energy market as those that may support the economies in pursuing towards decarbonization by increasing the share of renewables in the overall energy balance. In this group of alternative fuels, meat-and-bone meals being a post-production waste of the steadily developing meat industry, constitute a considerable proportion. Though they are rich in minerals, their direct use as natural fertilizer has been restricted to eliminate the spread of potential pathogens. This has focused the worldwide interest on thermal utilization of this type of fuel. Still, there are relatively few units dedicated to deal with large streams of meals. To provide their safe destruction, the conversion process must ensure specific conditions regarding the temperature and residence time. Therefore, most technologies developed to date involve the fluidized bed combustion. By virtue of nature and the variety of physicochemical properties of animal meals, the in-depth analyses of a raw material and its thermal behaviour need to be carried out on the way to develop the efficient and low-emission conversion technology. The concept of the said staged combustion of animal meal has therefore been supported by extensive studies, including the investigation of specific issues related to the process stages, such as drying, devolatilization, gas and char combustion. The developed technology appears to respond to the challenges encountered in the conversion of waste organics, providing the possibility to utilize fuels with a moisture content of up to 90%wt, while keeping the acceptable emission levels (NOx, CO, SO2 and HCl). The 12 MW operating pilot-scale plant tested while supplied with meat-and-bone meal has exhibited high efficiency, 88.4–84.8% depending on a facility load, offering a complete fuel combustion resulting in a flue gas being free from flammable gas compounds, and the ashes with low percentages of combustibles.

  • The Toolbox of Methods for Multidirectional Characterization of Dietary Nucleic Acids; Verification for Raw and Processed Food Products
    • Joanna Cieślewicz
    • Zuzanna Koziara
    • Wiktoria Ćwiklińska
    • Agnieszka Bartoszek-Pączkowska
    2021 Full text Food Analytical Methods

    Currently, the nutritional value of food is associated mainly with components such as proteins, carbohydrates, and lipids. However, another important macromolecules present in many foods are dietary nucleic acids (dietNA), i.e., DNA as well as both coding and non-coding RNAs. In the context of food chemistry and nutrition, dietNA are nowadays vastly neglected. In consequence, there are no dedicated methodologies to characterize dietNA. In this study, using raw or processed meat and plant products as model foodstuffs, we developed a toolbox of methods borrowed from other fields (histology, toxicology, molecular biology) that enable the initial characterization of dietNA as a necessary step on the way to systematic evaluation of their nutritional role. The proposed set of methods embraces (i) paraffin embedding of food samples and their staining to visualize the distribution and variety of dietNA in situ; (ii) comet assay to assess integrity of nuclear DNA with possible detection of DNA damage; (iii) dietNA isolation with and without RNAse digestion to determine the content of both DNA and RNA; (iv) electrophoretic separation of isolates to profile dietNA fragments. Such a combined methodological approach revealed clear differences between dietNA derived from raw and processed food products. We believe that the presented set of methods will encourage the broader research on dietNA to understand their role as a nutritionally relevant food component.

  • The Touristification of Italian Historic City Centres: The Lesson for Central Europe about the Airbnb Eruption
    • Łukasz Bugalski
    2021

    The unparalleled scale of the recent growth in tourism – the rise of the number of temporary visitors – could not have emerged without the impact on other socio‑economic aspects, namely, a change on the part of the destinations. Especially historic city centres are vulnerable to such an impact that could be manifested through diverse transformations of public space usage, housing market economics, availability of services, employment market, cultural heritage management, and everyday life of ordinary residents. Those processes may be indicated as the so‑called “touristification” – the kind of gentrification caused by the uncontrollable growth of the tourism economy. Therefore, together with the latest eruption of the short‑term rental market, identified with the foundation of the peer‑to‑peer Airbnb platform, those processes seem to accelerate and lead to the state of saturation known as “overtourism.” And as such, the ongoing touristification should be positioned in the very centre of urban tourism studies – the intersection of tourism studies and wider understand urban studies – becoming a fundamental issue for the future of the globe.

  • The unstable thermoelectric effect in non-stoichiometric Cu2Se during the non-equilibrium phase transition
    • Bartosz Trawiński
    • Marcin Łapiński
    • Bogusław Kusz
    2021 Full text JOURNAL OF MATERIALS SCIENCE

    The superionic α ↔ β phase transition in Cu1.96Se thermoelectric material is investigated by means of thermal analysis (DSC) and measurements of Seebeck coefficient and electrical conductivity. Results of the DSC measurements with 1–10 K/min heating and cooling rates show that the material is close to the equilibrium phase composition during the transformation. However, the kinetic limitation of the process exists, which is indicated by supercooling. At the beginning of the β → α transition, the most significant kinetic delay was attributed to the nucleation of the α phase. During the phase transformation, the Seebeck coefficient was lower than in a stabilised material (measured with 0.1 K/min heating/cooling rate). During cooling, a decrease from 130 μV/K (in a stabilised measurement) to 7 μV/K (5 K/min cooling rate) was observed. The deviation from the expected values of the Seebeck coefficient was correlated with the difference between the actual and equilibrium phase compositions.

  • The usage of the openBIM idea in architectural design on the example of Blender and BlenderBIM add-on
    • Michał Malewczyk
    2021 Full text Architectus

    The aim of the article is the research about the method and advancement of the openBIM idea implementation, clearly defined by the buildingSMART organization. The conducted analysis are limited to the Blender program and the BlenderBIM add-on and has been embedded in the context of the work of an architect and other IT solutions. The article presents four aspects of the openBIM concept implementation. The first approach relates to process of data exchanging between different computer applications using the open IFC standard. Another two focus on the method of creating and coding the three-dimensional geometry itself, through the prism of cooperation between various entities and further editing possibilities. The last aspect deals with the extension of the openBIM concept by combining it with the open-source idea. The author bases his considerations on the existing, analyzed scientific material, as well as on his own experience in the everyday of a designer and a teacher.

  • The Use of Cluster Analysis to Evaluate the Impact of COVID-19 Pandemic on Daily Water Demand Patterns
    • Paulina Dzimińska
    • Stanisław Drzewiecki
    • Marek Ruman
    • Klaudia Kosek
    • Karol Mikołajewski
    • Paweł Licznar
    2021 Full text Sustainability

    Proper determination of unitary water demand and diurnal distribution of water consumption (water consumption histogram) provides the basis for designing, dimensioning, and all analyses of water supply networks. It is important in the case of mathematical modelling of flows in the water supply network, particularly during the determination of nodal water demands in the context of Extended Period Simulation (EPS). Considering the above, the analysis of hourly water consumption in selected apartment buildings was performed to verify the justification of the application of grouping by means of k-means clustering. The article presents a detailed description of the adopted methodology, as well as the obtained results in the form of synthetic distributions of hourly water consumption, and the effect of the COVID-19 pandemic on their change.

  • The use of thermal imaging camera to estimate velocity profiles based on temperature distribution in a free convection boundary layer
    • Michał Ryms
    • Krzysztof Tesch
    • Witold Lewandowski
    2021 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

    This work describes an attempt to assess whether the temperature field from a thermal imaging camera can be converted into a velocity field with an accuracy sufficient for qualitative conducting or describing the phenomenon, i.e. when the Navier-Stokes, Fourier-Kirchhoff and continuity equations are mutually coupled. The consequence of this link between temperature fields and velocity is the possibility to formulate the hypothesis that knowledge of the temperature field value is theoretically synonymous with knowledge of the velocity field value. To examine this statement, both experimental and computational research were carried out. The experimental study involved determining the air temperature field by means of a thermal imaging camera in the vicinity of a vertical isothermal plate during free convection heat transfer. The calculation procedure leading from raw data obtained with an IR camera to the velocities has been presented. The calculation results were validated by comparing them with the results of experimental tests carried out under the same conditions. In addition, a comparative analysis using numerical calculations has also been carried out. Satisfactory compliance with current studies has been achieved in both cases.

  • Theoretical Encapsulation of Fluorouracil (5-FU) Anti-Cancer Chemotherapy Drug into Carbon Nanotubes (CNT) and Boron Nitride Nanotubes (BNNT)
    • Maryam Zarghami Dehaghani
    • Farrokh Yousefi
    • S. Mohammad Sajadi
    • Muhammad Tajammal Munir
    • Otman Abida
    • Sajjad Habibzadeh
    • Amin Hamed Mashhadzadeh
    • Navid Rabiee
    • Ebrahim Mostafavi
    • Mohammad Saeb
    2021 Full text MOLECULES

    Introduction: Chemotherapy with anti-cancer drugs is considered the most common approach for killing cancer cells in the human body. However, some barriers such as toxicity and side effects would limit its usage. In this regard, nano-based drug delivery systems have emerged as cost-effective and efficient for sustained and targeted drug delivery. Nanotubes such as carbon nanotubes (CNT) and boron nitride nanotubes (BNNT) are promising nanocarriers that provide the cargo with a large inner volume for encapsulation. However, understanding the insertion process of the anti-cancer drugs into the nanotubes and demonstrating drug-nanotube interactions starts with theoretical analysis. Methods: First, interactions parameters of the atoms of 5-FU were quantified from the DREIDING force field. Second, the storage capacity of BNNT (8,8) was simulated to count the number of drugs 5-FU encapsulated inside the cavity of the nanotubes. In terms of the encapsulation process of the one drug 5-FU into nanotubes, it was clarified that the drug 5-FU was more rapidly adsorbed into the cavity of the BNNT compared with the CNT due to the higher van der Waals (vdW) interaction energy between the drug and the BNNT. Results: The obtained values of free energy confirmed that the encapsulation process of the drug inside the CNT and BNNT occurred spontaneously with the free energies of −14 and −25 kcal·mol−1, respectively. Discussion: However, the lower value of the free energy in the system containing the BNNT unraveled more stability of the encapsulated drug inside the cavity of the BNNT comparing the system having CNT. The encapsulation of Fluorouracil (5-FU) anti-cancer chemotherapy drug (commercial name: Adrucil®) into CNT (8,8) and BNNT (8,8) with the length of 20 Å in an aqueous solution was discussed herein applying molecular dynamics (MD) simulation.

  • Theoretical investigation of the structural insights of the interactions of γ-Fe2O3 nanoparticle with (EMIM TFSI) ionic liquid
    • Adam Sieradzan
    • Cezary Czaplewski
    • Aleksandra Bielicka-Gieldon
    • Maciej Bobrowski
    • Artur Gieldon
    2021 JOURNAL OF MOLECULAR LIQUIDS

    One of the possible applications of ionic liquids is to produce electricity from heat. The iron oxide nanoparticle is a potent electrical particle, which is expected to improve the heat’s efficiency to electricity conversion, however, it is prone to aggregation and sedimentation, which hamper its application. One of the methods to enhance the nanoparticle’s solubility and electrical properties is the use of a stabilizing component in the production and application process. In this research, we studied, how the nanoparticle affects the properties of the 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM TFSI) ionic liquid. The citric acid was used as a nanoparticle stabilizing agent and led to decrease of the diffusion coefficient of the ionic liquid’s components. Our results indicated, that with the addition of the citric acid, strong solvation sphere around nanoparticle was formed. The presence of nanoparticles significantly reduced the diffusion of ionic liquid components. Finally, the citric acid was found to be the strongest nanoparticle binding component of the studied system, and therefore it was able to stabilize the nanoparticle in solution.

  • Therapeutic Potential of Multifunctional Derivatives of Cholinesterase Inhibitors
    • Maja Przybyłowska
    • Krystyna Dzierzbicka
    • Szyman Kowalski
    • Klaudia Chmielewska
    • Iwona Inkielewicz-Stępniak
    2021 Full text Current Neuropharmacology

    The aim of this work is review of tacrine analogues from the last three years, which were not included in the latest review work, donepezil and galantamine hybrids from 2015 and rivastigmine derivatives from 2014. In this account we summarize the efforts toward the development and characterization of non-toxic inhibitors of cholinesterases based on mentioned drugs with various interesting additional properties such as antioxidant, decreasing beta-amyloid plaque aggregation, nitric oxide production, pro-inflammatory cytokines release, monoamine oxidase-B activity, cytotoxicity and oxidative stress in vitro and in animal model that classify these hybrids as potential multifunctional therapeutic agents for Alzheimer's disease. Moreover, herein, we have described the cholinergic hypothesis, mechanisms of neurodegeneration and current pharmacotherapy of Alzheimer's disease which is based on the restoration of cholinergic function through blocking enzymes that break down acetylcholine.

  • Thermal and Hydrodynamic Phenomena in the Stagnation Zone — Impact of the Inlet Turbulence Characteristics on the Numerical Analyses
    • Tomasz Kura
    • Jan Wajs
    • Elzbieta Fornalik-Wajs
    • Sasa Kenjeres
    • Sebastian Gurgul
    2021 Full text ENERGIES

    One of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied, for example, in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to the origin of this impact are still unanswered. In general, the wall-jet interaction and the near-wall turbulence are supposed to be its main reason, but their accurate numerical analysis is still very challenging. The authors’ aim was to construct the numerical model which can represent the real phenomena with good or very good accuracy. Starting with an analysis of single jet and obtaining the agreement with experimental data, it will be possible to extend the model towards the whole minijets heat exchanger. The OpenFOAM software, Bracknell, UK was used for that purpose, with our own implementation of the ζ-f turbulence model. The most difficult area to model is the stagnation region, where the thermal effects are the most intensive and, at the same time, strongly affected by the conditions in the pipe/nozzle/orifice of various size (conventional, mini, micro), from which the jet is injected. In the following article, summary of authors’ findings, regarding significance of the velocity profile and turbulence intensity at the jet place of discharge are presented. In addition, qualitative analysis of the heat transfer enhancement is included, in relation to the inlet conditions. In the stagnation point, Nusselt number differences reached the 10%, while, in general, its discrepancy in relation to inlet conditions was up to 23%.

  • Thermal and Mechanical Behavior of Elastomers Incorporated with Thermoregulating Microcapsules
    • Janusz Datta
    • Patrycja Trzebiatowska,
    • Ana M. Borreguero
    • Irene Izarra
    • Ignacio Garrido
    • Angel Serrano
    • Juan F. Rodríguez
    • Manuel Carmona
    2021 Full text Applied Sciences

    Polyurethane (PU) is one of the principal polymers in the global plastic market thanks to its versatility and continuous improvement. In this work, PU elastomeric materials having thermoregulating properties through the incorporation of microcapsules (mSD-(LDPE·EVA-RT27)) from low-density polyethylene and vinyl acetate containing paraffin®RT27 as PCM were produced. Elastomers were synthesized while varying the molar ratio [NCO]/[OH] between 1.05 and 1.1 and the microcapsule (MC) content from 0.0 to 20.0 wt.%. The successful synthesis of the PUs was confirmed by IR analyses. All the synthesized elastomers presented a structure formed by a net of spherical microparticles and with a minimum particle size for those with 10 wt.% MC. The density and tensile strength decreased with the MC content, probably due to worse distribution into the matrix. Elastomer E-1.05 exhibited better structural and stability properties for MC contents up to 15 wt.%, whereas E-1.1, containing 20 wt.% MC, revealed mechanical and thermal synergy effects, demonstrating good structural stability and the largest latent heat. Hence, elastomers having a large latent heat (8.7 J/g) can be produced by using a molar ratio [NCO]/[OH] of 1.1 and containing 20 wt.% mSD-(LDPE·EVA-RT27).

  • Thermal and technological aspects of double face grinding of C45 carbon steel
    • Mariusz Deja
    • Linus Lichtschlag
    • Eckart Uhlmann
    2021 Full text Journal of Manufacturing Processes

    In grinding, the contact zone temperature is a decisive factor influencing the achievable surface quality and the grinding tool wear. In contrast to other grinding processes, only few information regarding double face grinding with planetary kinematics when processing steel is known up to date. Since the successive substitution of in-dustrial double-sided lapping processes by double-sided grinding, it has become necessary to the conducted research in order to provide deeper understanding of the process and factors that influence it. To determine the workpiece temperature during grinding of C45 components, silicon temperature sensors were integrated into the workpiece holders and technological investigations were carried out. The influences and interactions of the mean cutting speed, cooling lubricant flow rate and cutting ability of the grinding wheels on the resulting workpiece temperature were analysed. Subsequently, modelling enabled an empirical estimation of the resulting workpiece temperature for processes in the investigated test area. With regard to the design and optimization of processes for machining plane-parallel workpiece surfaces, this model is a helpful tool for avoiding thermally induced workpiece damage and reduction of tool wear. Furthermore, the method can be used to conduct further ex-aminations on the grinding process and to reduce the amount of cooling lubricant used, to improve life cycle assessment.

  • Thermal Buckling Analysis of Circular Bilayer Graphene sheets Resting on an Elastic Matrix Based on Nonlocal Continuum Mechanics
    • M. Ahmad Pour
    • M. E. Golmakani
    • Mohammad Malikan
    2021 Full text Journal of Applied and Computational Mechanics

    In this article, the thermal buckling behavior of orthotropic circular bilayer graphene sheets embedded in the Winkler–Pasternak elastic medium is scrutinized. Using the nonlocal elasticity theory, the bilayer graphene sheets are modeled as a nonlocal double–layered plate that contains small scale effects and van der Waals (vdW) interaction forces. The vdW interaction forces between the layers are simulated as a set of linear springs using the Lennard–Jones potential model. Using the principle of virtual work, the set of equilibrium equations are obtained based on the first-order shear deformation theory (FSDT) and nonlocal differential constitutive relation of Eringen. Differential quadrature method (DQM) is employed to solve the governing equations for simply-supported and clamped boundary conditions. Finally, the effects of the small scale parameter, vdW forces, aspect ratio, elastic foundation, and boundary conditions are considered in detail.

  • Thermal utilization of meat-and-bone meal using the rotary kiln pyrolyzer and the fluidized bed boiler – The performance of pilot-scale installation
    • Marcin Kantorek
    • Krzysztof Jesionek
    • Sylwia Polesek-Karczewska
    • Paweł Ziółkowski
    • Michał Stajnke
    • Janusz Badur
    2021 Full text RENEWABLE ENERGY

    Thermal utilization of meat-and-bone meal (MBM) is subject to stringent regulations that are meant to provide elimination of any potential pathogens. Incineration as well as other possible routes for thermal conversion of MBM are still at the research state. The universal technology was developed that allows to combust various types of waste organic materials, including animal waste, municipal solid waste and sludge, mixed at any ratio with different types of biomass. It provides the possibility to utilize the wasteand- biomass fuel blends of up to 90%wt of moisture content, while maintaining the allowable pollutant emissions and soil contamination. This regards mainly NOx, SO2, HCl and VOC. Contrary to the typical large scale grate boilers used for waste burning, the developed operating pilot-scale plant with a capacity of 12 MW offers the complete combustion of MBM, resulting in a flue gas which is proved to be free of flammable gaseous components and sooty particles in slag and fly ash. The thermal decomposition and combustion of waste using this technology ensures thermal conversion of chemical energy contained in waste and biomass. The efficiency of the prototype installation varied between 84.8 and 88.4% depending on the facility load.

  • Thermodynamic Analysis of Negative CO2 Emission Power Plant Using Aspen Plus, Aspen Hysys, and Ebsilon Software
    • Paweł Ziółkowski
    • Paweł Madejski
    • Milad Amiri
    • Tomasz Kuś
    • Kamil Stasiak
    • Navaneethan Subramanian
    • Halina Pawlak-kruczek
    • Janusz Badur
    • Łukasz Niedźwiecki
    • Dariusz Mikielewicz
    2021 Full text ENERGIES

    Abstract: The article presents results of thermodynamic analysis using a zero-dimensional mathematical models of a negative CO2 emission power plant. The developed cycle of a negative CO2 emission power plant allows the production of electricity using gasified sewage sludge as a main fuel. The negative emission can be achieved by the use this type of fuel which is already a “zeroemissive” energy source. Together with carbon capture installation, there is a possibility to decrease CO2 emission below the “zero” level. Developed models of a novel gas cycle which use selected codes allow the prediction of basic parameters of thermodynamic cycles such as output power, efficiency, combustion composition, exhaust temperature, etc. The paper presents results of thermodynamic analysis of two novel cycles, called PDF0 and PFD1, by using different thermodynamic codes. A comparison of results obtained by three different codes offered the chance to verify results because the experimental data are currently not available. The comparison of predictions between three different software in the literature is something new, according to studies made by authors. For gross efficiency (54.74%, 55.18%, and 52.00%), there is a similar relationship for turbine power output (155.9 kW, 157.19 kW, and 148.16 kW). Additionally, the chemical energy rate of the fuel is taken into account, which ultimately results in higher efficiencies for flue gases with increased steam production. A similar trend is assessed for increased CO2 in the flue gas. The developed precise models are particularly important for a carbon capture and storage (CCS) energy system, where relatively new devices mutually cooperate and their thermodynamic parameters affect those devices. Proposed software employs extended a gas–steam turbine cycle to determine the effect of cycle into environment. First of all, it should be stated that there is a slight influence of the software used on the results obtained, but the basic tendencies are the same, which makes it possible to analyze various types of thermodynamic cycles. Secondly, the possibility of a negative CO2 emission power plant and the positive environmental impact of the proposed solution has been demonstrated, which is also a novelty in the area of thermodynamic cycles

  • Thermodynamic Studies of Interactions between Sertraline Hydrochloride and Randomly Methylated β-Cyclodextrin Molecules Supported by Circular Dichroism Spectroscopy and Molecular Docking Results
    • Sylwia Belica-Pacha
    • Mateusz Daśko
    • Vyacheslav Buko
    • Ilya Zavodnik
    • Katarzyna Miłowska
    • Maria Bryszewska
    2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    The interaction between sertraline hydrochloride (SRT) and randomly methylated β-cyclodextrin (RM β CD) molecules have been investigated at 298.15 K under atmospheric pressure. The method used—Isothermal Titration Calorimetry (ITC) enabled to determine values of the thermodynamic functions like the enthalpy (DH), the entropy (DS) and the Gibbs free energy (DG) of binding for the examined system. Moreover, the stoichiometry coefficient of binding (n) and binding/association constant (K) value have been calculated from the experimental results. The obtained outcome was compared with the data from the literature for other non-ionic βCD derivatives interacting with SRT and the enthalpy-entropy compensation were observed and interpreted. Furthermore, the connection of RM β CD with SRT was characterized by circular dichroism spectroscopy (CD) and complexes of βCD derivatives with SRT were characterized through the computational studies with the use of molecular docking (MD).

  • THERMOMECHANICAL PERFORMANCE OF FLEXIBLE POLYURETHANE FOAMS AS A FUNCTION OF THE ISOCYANATE INDEX
    • Aleksander Hejna
    • Paulina Kosmela
    • Adam Olszewski
    • Łukasz Zedler
    • Krzysztof Formela
    2021

    Polyurethane foams are very versatile materials applied in different branches of industry. Their popularity is attributed, among others, to the flexibility in engineering their mechanical performance by the adjustment of their formulations. One of the most crucial factors is the isocyanate index, determining the ratio between the free hydroxyl and isocyanate groups present in the polyurethane system. By the change of this ratio, the mechanical properties of foams may be adjusted. In the presented paper, we presented the isocyanate index's influence during foams’ preparation on their thermomechanical performance analyzed by the dynamic mechanical analysis.

  • Thermo-Mechanical Simulation of Underwater Friction Stir Welding of Low Carbon Steel
    • Shabbir Memon
    • Jacek Tomków
    • Hesamoddin Aghajani Derazkola
    2021 Full text Materials

    This article investigates the flow of materials and weld formation during underwater friction stir welding (UFSW) of low carbon steel. A thermo-mechanical model is used to understand the relation between frictional heat phenomena during the welding and weld properties. To better understand the effects of the water environment, the simulation and experimental results were compared with the sample prepared by the traditional friction stir welding (FSW) method. Simulation results from surface heat diffusion indicate a smaller preheated area in front of the FSW tool declined the total generated heat in the UFSWed case compared to the FSWed sample. The simulation results revealed that the strain rate of steel in the stir zone (SZ) of the FSWed joint is higher than in the UFSWed case. The microstructure of the welded sample shows that SZ’s microstructure at the UFSWed case is more refined than the FSWed case due to the higher cooling rate of the water environment. Due to obtained results, the maximum temperatures of FSWed and UFSWed cases were 1228 °C and 1008 °C. Meanwhile, the simulation results show 1200 °C and 970 °C for conventional and underwater FSW samples, respectively. The maximum material velocity in SZ predicted 0.40 m/s and 0.32 m/s for FSW and underwater FSWed samples. The better condition in the UFSW case caused the ultimate tensile strength of welded sample to increase ~20% compared to the FSW joint.

  • Thermo-oxidative exfoliation of carbon black from ground tire rubber as potential reinforcement in green tires
    • Adeel Hassan
    • Zhen Zhang
    • Krzysztof Formela
    • Shifeng Wang
    2021 COMPOSITES SCIENCE AND TECHNOLOGY

    Considering the balance between rapidly growing global tire demand and scarcity of natural resources, recycling and reclaiming techniques of tire rubber have become the state of the art. Herein, we set out to implement a self-designed thermo-oxidative reactor for the exfoliation of carbon black (CB) from ground tire rubber, which is efficiently functioned under a thermo-oxidative reclaiming condition without any additive. The exfoliation of CB from rubber vulcanizate was realized by scission of main chain, and of cross-linked network. The degree of scission was discussed through gel permeation chromatography and using Horikx theory. Sol fraction tremendously increased to 66.0% after thermo-oxidative reclamation at 200 °C for 20 min. Thermo-oxidative scission underwent through the oxidative cleavage of main chain, and of sulfur cross-links, proved by Fourier transform infrared spectroscopy. The ultrafine exfoliation of CB from rubber proved by field emission scanning electron microscopy. The exfoliation was further improved by two roll milling. Exfoliated rubber was incorporated within tire rubber composites as a reinforcing material due to the core-shell structured CB, which was observed with increased effects to the rubber composites. This work presents a potential contribution to the industrial recycling for future applications and to control the pollution of waste tires.

  • Thermoplastic starch nanocomposites using cellulose-rich Chrysopogon zizanioides nanofibers
    • Midhun Dominic C.D.
    • Derval dos Santos Rosa
    • Paulo Henrique Camani
    • Athira S Kumar
    • Neenu K.v.
    • P.M. Sabura Begum
    • Divya Dinakaran
    • Effina John
    • Donna Baby
    • Meenu Mariya Thomas
    • Jaison M. Joy
    • Jyotishkumar Parameswaranpillai
    • Mohammad Saeb
    2021 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES

    Green thermoplastic starch (TPS) nanocomposite films aided by cellulose nanofibers (CNFs) from Chrysopogon zizanioides roots were developed and characterized. When compared to other lignocellulosic fibers, Chrysopogon zizanioides roots revealed exceptionally high cellulose content (~48%). CNFs were separated using an environmentally friendly acid isolation technique that included three stages: (i) alkali treatment; (ii) bleaching; and (iii) mild acid hydrolysis using oxalic acid in an autoclave. Following that, green nanocomposite films were made from potato starch using the solution casting process, by which we used glycerol (30 wt%) to make thermoplastic starch. Then, cellulose nanofibers in different concentrations (0, 1, 2, 3, 4 wt%) were added to the thermoplastic starch matrix. The isolated CNFs had diameters in the range of 17–27 nm. Besides, these nanostructures presented a very high crystallinity index (~65%), thereby enhanced the thermal stability. TPS/CNF green nanocomposites containing 3 wt% CNFs had exceptional tensile strength (~161%), tensile modulus (~167%), thermal stability, and crystallinity. As a result, nanocomposite films made of starch and cellulose nanofibers (3 wt%) extracted from Chrysopogon zizanioides roots would be alternatives for sustainable packaging. It can be concluded that Chrysopogon zizanioides roots have high potential for polymer industry.

  • Three Principles for Healthy Living with Light and Lighting
    • Karolina Zielińska-Dąbkowska
    • Ruth Kelly Waskett
    2021 Full text ARC Lighting In Architecture

    The lockdown measures applied to cities and towns during the worldwide Covid-19 pandemic have had a widespread impact on people’s lives. Some have found themselves confined to their homes, with limited social contact and a reduced quality of life. Others have found that the lockdown improved their wellbeing, as more time was spent outside, instead of commuting and working in an office building, plus the benefits of spending increased quality time with loved ones. The pandemic raised public consciousness about the need to take control of our own wellbeing and health: in particular, to take greater care of immunity. There was also concern about the consequences of extended time spent in indoor spaces, which can create mental fatigue that can manifest itself in a number of ways, including reduced productivity, lack of concentration and in some cases, depression. Many people soon realised the simple things in life that had previously been taken for granted, such as access to daylight and contact with nature, play a vital role in mental health and wellbeing.

  • Three-dimensional modeling and automatic analysis of the human nasal cavity and paranasal sinuses using the computational fluid dynamics method
    • Dmitry Tretiakow
    • Krzysztof Tesch
    • Jarosław Meyer-Szary
    • Karolina Markiet
    • Andrzej Skorek
    2021 Full text EUROPEAN ARCHIVES OF OTO-RHINO-LARYNGOLOGY

    Purpose The goal of this study was to develop a complete workflow allowing for conducting computational fluid dynam- ics (CFD) simulation of airflow through the upper airways based on computed tomography (CT) and cone-beam computed tomography (CBCT) studies of individual adult patients. Methods This study is based on CT images of 16 patients. Image processing and model generation of the human nasal cavity and paranasal sinuses were performed using open-source and freeware software. 3-D Slicer was used primarily for segmentation and new surface model generation. Further processing was done using ­Autodesk ® Meshmixer TM. The gov- erning equations are discretized by means of the finite volume method. Subsequently, the corresponding algebraic equation systems were solved by OpenFOAM software. Results We described the protocol for the preparation of a 3-D model of the nasal cavity and paranasal sinuses and high- lighted several problems that the future researcher may encounter. The CFD results were presented based on examples of 3-D models of the patient 1 (norm) and patient 2 (pathological changes). Conclusion The short training time for new user without a prior experience in image segmentation and 3-D mesh editing is an important advantage of this type of research. Both CBCT and CT are useful for model building. However, CBCT may have limitations. The Q criterion in CFD illustrates the considerable complication of the nasal flow and allows for direct evaluation and quantitative comparison of various flows and can be used for the assessment of nasal airflow.

  • Three-Dimensional Printing of Bone Models
    • Angela Andrzejewska
    2021

    The trabecular bone occurs, for example, in the femoral heads. Understanding the phenomenon of bone tissue degeneration can be the basis for the possibility of looking for alternative methods of surgical treatment of bone loss. The paper presents the results of the trabecular bone model, which was produced in additive manufacturing method with fused filament fabrication technology. The verification of the mechanical behavior of the trabecular bone model was based on the analysis of uniaxial compression test. The model was also conditioned under degradation process to determine the influence of the physiological fluid environment due to changes in the mechanical response of the modeled bone. The obtained results showed that the mechanical strength of the proposed spongy bone model and the method of its production allow to obtain strength values close to the natural spongy bone. In addition, the strength did not change during the 4-week degradation process.

  • THREE-LEVEL F-TYPE INVERTER
    • Charles Odeh
    • Arkadiusz Lewicki
    • Marcin Morawiec
    • Dmytro Kondratenko
    2021 IEEE TRANSACTIONS ON POWER ELECTRONICS

    Given the recent available IGBT switch modules up to 6.5 kV, 1200 A rating, the prospect of the diode-free variant topology of the three-level neutral-point-clamped (3-level, T-type) inverter in certain medium voltage applications is bright; due to its small part count and low conduction losses compared to the diode-clamped NPC inverter. However, within this voltage range, the input dc voltage rating of 50% of the switches per inverter phase-leg still poses limitations to the deployment of 3-level T-type inverter. In view of these limitations, a reconfigured four-switch per phase-leg power circuit for 3-level inverter (F-type) is presented in this paper. The common node of the bidirectional switch in T-type inverter is explored to have only one power switch rated at input dc voltage and 3 switches rated at half the input dc voltage, per inverter-leg. This reduced voltage stress has inverter cost and loss implications. The performances and competitiveness of the three-level, F-type inverter are analyzed in detail and demonstrated with a hardware prototype. Results reveal that it has the potentials of being considered a real alternative to 3-level, T-type inverters for certain low- and medium-voltage applications.

  • Time-current tripping characteristics of RCDs for sinusoidal testing current
    • Stanisław Czapp
    2021

    Low-voltage electrical installations are verified initially – before being put into operation, as well as periodically – during their utilization. According to the IEC standards, the scope of the verification includes measurements of both the tripping current and the disconnection time of residual current devices (RCDs). Experiences in RCDs testing show that disconnection times of two or more similar RCDs can be quite different. Significant differences in disconnection times are also noticed for the same RCD in the consecutive trials. This paper presents the result of the test of twenty-four RCDs. Their real tripping current, as well as disconnection time, have been verified. Differences in the obtained values of disconnection times are commented, and their possible sources are indicated.

  • Tin Oxide Encapsulated into Pyrolyzed Chitosan as a Negative Electrode for Lithium Ion Batteries
    • Andrzej Nowak
    • Maria Gazda
    • Marcin Łapiński
    • Zuzanna Zarach
    • Konrad Trzciński
    • Mariusz Szkoda
    • Szymon Mania
    • Jinjin Li
    • Robert Tylingo
    2021 Full text Materials

    Tin oxide is one of the most promising electrode materials as a negative electrode for lithium-ion batteries due to its higher theoretical specific capacity than graphite. However, it suffers lack of stability due to volume changes and low electrical conductivity while cycling. To overcome these issues, a new composite consisting of SnO2 and carbonaceous matrix was fabricated. Naturally abundant and renewable chitosan was chosen as a carbon source. The electrode material exhibiting 467 mAh g−1 at the current density of 18 mA g−1 and a capacity fade of only 2% after 70 cycles is a potential candidate for graphite replacement. Such good electrochemical performance is due to strong interaction between amine groups from chitosan and surface hydroxyl groups of SnO2 at the preparation stage. However, the charge storage is mainly contributed by a diffusion-controlled process showing that the best results might be obtained for low current rates

  • To i-vote or not to i-vote: Drivers and barriers to the implementation of internet voting
    • Nathan Licht
    • David Duenas Cid
    • Iuliia Krivonosova
    • Robert Krimmer
    2021 Full text

    This paper investigates the drivers and barriers of internet voting and the implications of a global pandemic for the development of the respective technology. In contrast to the expected uptake in the early 2000s of internet voting, the technology is still rather seldomly used in election systems around the world. The paper at hand explores the different forces that drive or impede internet voting adoption from a political, social, legal, organizational, contextual, economic and technological perspective. In an exploratory approach, 18 expert interviews and extensive complementary desk research were conducted. The findings identified 15 general drivers and 15 general barriers for the process of internet voting adoption. The evidence suggests that for a large part, the political features, trust and perception are the most pivotal factors to internet voting development.

  • Topological, nonreciprocal, and multiresonant slow light beyond the time-bandwidth limit
    • Kosmas L. Tsakmakidis
    • Konstantinos Baskourelos
    • Tomasz Stefański
    2021 Full text APPLIED PHYSICS LETTERS

    Topologically protected transport has recently emerged as an effective means to address a recurring problem hampering the field of slow light for the past two decades: its keen sensitivity to disorders and structural imperfections. With it, there has been renewed interest in efforts to overcome the delay-time-bandwidth limitation usually characterizing slow-light devices, on occasion thought to be a fundamental limit. What exactly is this limit, and what does it imply? Can it be overcome? If yes, how could topological slow light help, and in what systems? What applications might be expected by overcoming the limit? Our Perspective here attempts addressing these and other related questions while pointing to important new functionalities both for classical and quantum devices that overcoming the limit can enable.

  • Torque capacity of multidisc wet clutch with reference to friction occurrence on its spline connections
    • Marcin Bąk
    2021 Full text Scientific Reports

    In this article developed mathematical model that includes friction occurrence on spline connections is presented. The work also contains results of experimental research on torque capacity of multidisc wet clutch. These results are expressed as a function of contact pressure for different number of friction surfaces. Due to increased interest in research concerning multidisc wet clutches it is essential to determine impact of friction on fit connections on transmitted torque. Analytical calculations that include both known loss coefficient and assumed lack of friction on fit connections are compared to results of experiments. The paper contains detailed description of test stand and methodology of experiment. As a result of conducted tests it was found that correction coefficients known from literature are highly inaccurate. Measured values of torque indicate that transmitted torque reach significantly higher values. It was also revealed that after slippage appeared, the pressure plate usually moved in the direction of exerted clamping force, but movement in reversed direction also took place for some experiments. While movement corresponding to clamping force reached ca. 0.08 mm, in opposite direction amounted to 0.02 mm. Furthermore, studies presented that lapping of adjacent friction surfaces greatly affects differences between respective results obtained for a specific experiment.

  • Torque Transmitted by Multi-plate Wet Clutches in Relation to Number of Friction Plates and Their Dimensions
    • Marcin Bąk
    • Piotr Patrosz
    • Paweł Śliwiński
    2021

    In the paper results of experimental tests on multi-plate wet clutch torque capacity for various diameters and numbers of friction plates are presented. Construction of an apparatus for laboratory tests of wet clutch engagement, drag torque and maximum torque is shown. Methodology of maximum torque capacity experiment and hydraulic circuit diagram, which supplies a motor and an actuator for the experiment are described. Analytically calculated values of torque capacity are compared to results obtained with laboratory tests. Additionally, the article includes FEM analysis, that was used to obtain pressure distribution on every friction surface in relation to force applied to the assembly and to determine differences in these distributions. The analysis has helped to determine a mean radius of sliding interface on each surface and to compare their values to other plates and to result calculated analytically. A diagram is shown in the article, that demonstrates pressure concentration as a function of number of friction surfaces.

  • Total chromatic sum for trees
    • Michał Małafiejski
    • Krzysztof Ocetkiewicz
    • Ewa Kubicka
    • Grzegorz Kubicki
    2021

    The total chromatic sum of a graph is the minimum sum of colors (natural numbers) taken over all proper colorings of vertices and edges of a graph. We provide infinite families of trees for which the minimum number of colors to achieve the total chromatic sum is equal to the total chromatic number. We construct infinite families of trees for which these numbers are not equal, disproving the conjecture from 2012.

  • Total Completion Time Minimization for Scheduling with Incompatibility Cliques
    • Klaus Jansen
    • Alexandra Lassota
    • Marten Maack
    • Tytus Pikies
    2021

    This paper considers parallel machine scheduling with incompatibilities between jobs. The jobs form a graph equivalent to a collection of disjoint cliques. No two jobs in a clique are allowed to be assigned to the same machine. Scheduling with incompatibilities between jobs represents a well-established line of research in scheduling theory and the case of disjoint cliques has received increasing attention in recent years. While the research up to this point has been focused on the makespan objective, we broaden the scope and study the classical total completion time criterion. In the setting without incompatibilities, this objective is well-known to admit polynomial time algorithms even for unrelated machines via matching techniques. We show that the introduction of incompatibility cliques results in a richer, more interesting picture. We prove that scheduling on identical machines remains solvable in polynomial time, while scheduling on unrelated machines becomes APX-hard. Next, we study the problem under the paradigm of fixed-parameter tractable algorithms (FPT). In particular, we consider a problem variant with assignment restrictions for the cliques rather than the jobs. We prove that, despite still being APX-hard, it can be solved in FPT time with respect to the number of cliques. Moreover, we show that the problem on unrelated machines can be solved in FPT time for reasonable parameters, in particular, the parameter combination: maximum processing time, number of job kinds, and number of machines or maximum processing time, number of job kinds, and number of cliques. The latter results are extensions of known results for the case without incompatibilities, and can even be further extended to the case of total weighted completion time. All of the FPT results make use of n-fold Integer Programs that recently received great attention by proving their usefulness for scheduling problems.

  • Toward Intelligent Recommendations Using the Neural Knowledge DNA
    • Guangjian Ning
    • Chunwang Wu
    • Haoxi Zhang
    • Edward Szczerbicki
    2021 Full text CYBERNETICS AND SYSTEMS

    In this paper we propose a novel recommendation approach using past news click data and the Neural Knowledge DNA (NK-DNA). The Neural Knowledge DNA is a novel knowledge representation method designed to support discovering, storing, reusing, improving, and sharing knowledge among machines and computing systems. We examine our approach for news recommendation tasks on the MIND benchmark dataset. By taking advantages of NK-DNA, deep learning, and the SOEKS technologies, our approach can learn from users’ past behaviors to form reading preference of the user, and reuse learned knowledge for improving the recommendation performance.

  • Towards a classification of networks with asymmetric inputs
    • Manuela Aguiar
    • Ana Dias
    • Pedro Da Costa Soares
    2021 Full text NONLINEARITY

    Coupled cell systems associated with a coupled cell network are determined by (smooth) vector fields that are consistent with the network structure. Here, we follow the formalisms of Stewart et al (2003 SIAM J. Appl. Dyn. Syst. 2, 609–646), Golubitsky et al (2005 SIAM J. Appl. Dyn. Syst. 4, 78–100) and Field (2004 Dyn. Syst. 19, 217–243). It is known that two non-isomorphic n-cell coupled networks can determine the same sets of vector fields - these networks are said to be ordinary differential equation (ODE)-equivalent. The set of all n-cell coupled networks is so partitioned into classes of ODE-equivalent networks. With no further restrictions, the number of ODE-classes is not finite and each class has an infinite number of networks. Inside each ODE-class we can find a finite subclass of networks that minimize the number of edges in the class, called minimal networks. In this paper, we consider coupled cell networks with asymmetric inputs. That is, if k is the number of distinct edges types, these networks have the property that every cell receives k inputs, one of each type. Fixing the number n of cells, we prove that: the number of ODE-classes is finite; restricting to a maximum of n(n − 1) inputs, we can cover all the ODE-classes; all minimal n-cell networks with n(n − 1) asymmetric inputs are ODE-equivalent. We also give a simple criterion to test if a network is minimal and we conjecture lower estimates for the number of distinct ODE-classes of n-cell networks with any number k of asymmetric inputs. Moreover, we present a full list of representatives of the ODE-classes of networks with three cells and two asymmetric inputs.

  • Towards a modification of a regulatory framework aiming at bunker oil spill prevention from ships - A design aspect of bunker tanks vents location guided by CFD simulations
    • Przemysław Krata
    • Jacek Jachowski
    2021 RELIABILITY ENGINEERING & SYSTEM SAFETY

    Although accidental bunker oil spills at seaway are relatively rare events, they can be pose real threat to the natural marine environment. One of the reasons for the bunker spill to occur is a design failure; one of the ways it can demonstrate is an improper location or height of vent heads, leading to a bunker oil discharge during heavy rolling, due to sloshing phenomenon. Design of a ship and her systems is guided by various formal conventions and ensuing requirements by classification societies, as a result of past experience and background knowledge. Nevertheless, the requirements are not always fully effective and up to date. An example of such situation is an accidental spill from a deep bunker tank, that has been arranged and designed according to the valid rules and regulations, however not accounting for dynamic physical phenomena that when occur lead to discharging the fuel through the vent. Therefore, the contemporary regulation of vent arrangement for some specific bunker tanks design options seems insufficient and requires scientific insight. To this end, we propose science-based regulatory framework modification. This is done through examining the location of the deep tank vent with regard to dynamics of the oil sloshing phenomenon, adopting CFD-based approach that is suitable for the purpose of onboard tank design. Moreover, an experimental validation of numerical simulations outcome is presented which makes the study credible. The proposed approach is both scientifically valid and practically feasible. Some CFD simulations of liquid sloshing need to be carried out for certain bunker tank design options. The additional burden at the design stage is not significantly time consuming thus remains justified, especially nowadays when CFD has become an industrial standard in some branches. The proposed solution attempts to improve the contemporary regulations in the area of bunker oil overflow prevention, reducing the negative impact of maritime transportation on the environmental safety.

  • Towards a multi-basin SWAT model for the migration of nutrients and pesticides to Puck Bay (Southern Baltic Sea)
    • Paweł Wielgat
    • Dominika Kalinowska
    • Adam Szymkiewicz
    • Piotr Zima
    • Beata Jaworska-Szulc
    • Ewa Wojciechowska
    • Nicole Nawrot
    • Karolina Matej-Łukowicz
    • Lidia Anita Dzierzbicka-Glowacka
    2021 Full text PeerJ

    Background This paper analyzes the impact of changes in fertilization on crop yields and the runoff of nutrients from a small agricultural catchment (176 km2) to a shallow bay, using the SWAT model. Puck Bay is part of the Gulf of Gdansk and belongs to the Baltic Sea. The whole area of Puck Bay (364 km2) is protected (Natura 2000) yet despite this it suffers from eutrophication problems due to the relatively minimal depth and difficult water exchange. Methods The paper presents a comparison of the calculated yields and the runoff of nutrients and pesticides in the SWAT model, for a small agricultural coastal catchment. Calculations were made for 13 crop scenarios with weather data from 2011 to 2019. For each crop, an agriculture calendar was made. Two variants of fertilization were considered (autofertilization mode and according to the calendar). The nutrient runoff was calculated depending on the adopted scenario. In addition, the fate of selected pesticides was simulated. Results Depending on the crop, the annual load of NO3into the stream ranged from 0.74 to 3.65 kg ha−1. The annual load of organic phosphorous into the stream was between 0.686 and 3.64 kg ha−1. This is lower than in the majority of EU or Baltic countries. The surface runoff of dissolved Glyphosate was equal to 286 mg ha−1. The annual loads of nutrients from the catchment area are equivalent in both fertilization modes. Regardless of the selected fertilization mode, in addition to the dosage, the form of nutrients is important for the model.

  • Towards Cancer Patients Classification Using Liquid Biopsy
    • Sebastian Cygert
    • Franciszek Górski
    • Piotr Juszczyk
    • Sebastian Lewalski
    • Krzysztof Pastuszak
    • Andrzej Czyżewski
    • Anna Supernat
    2021

    Liquid biopsy is a useful, minimally invasive diagnostic and monitoring tool for cancer disease. Yet, developing accurate methods, given the potentially large number of input features, and usually small datasets size remains very challenging. Recently, a novel feature parameterization based on the RNA-sequenced platelet data which uses the biological knowledge from the Kyoto Encyclopedia of Genes and Genomes, combined with a classifier based on the Convolutional Neural Network (CNN), allowed significantly improving the classification accuracy. In this work, we take a closer look at this approach and find that similar results can be obtained using significantly smaller models. Additionally, competitive results were achieved using gradient boosting. Since it has another advantage of adding interpretability to the model, we further analyze it in this work.

  • Towards Computer-Aided Graphene Covered TiO2-Cu/(CuxOy) Composite Design for the Purpose of Photoinduced Hydrogen Evolution
    • Łukasz Lewandowski
    • Agnieszka Gajewicz-Skretna
    • Tomasz Klimczuk
    • Grzegorz Trykowski
    • Kostiantyn Nikiforow
    • Wojciech Lisowski
    • Anna Gołąbiewska
    • Adriana Zaleska-Medynska
    2021 Full text Catalysts

    In search a hydrogen source, we synthesized TiO2-Cu-graphene composite photocatalyst for hydrogen evolution. The catalyst is a new and unique material as it consists of copper-decorated TiO2 particles covered tightly in graphene and obtained in a fluidized bed reactor. Both, reduction of copper from Cu(CH3COO) at the surface of TiO2 particles and covering of TiO2-Cu in graphene thin layer by Chemical Vapour Deposition (CVD) were performed subsequently in the flow reactor by manipulating the gas composition. Obtained photocatalysts were tested in regard to hydrogen generation from photo-induced water conversion with methanol as sacrificial agent. The hydrogen generation rate for the most active sample reached 2296.27 mol H2 h1 gcat 1. Combining experimental and computational approaches enabled to define the optimum combination of the synthesis parameters resulting in the highest photocatalytic activity for water splitting for green hydrogen production. The results indicate that the major factor affecting hydrogen production is temperature of the TiO2-Cu-graphene composite synthesis which in turn is inversely correlated to photoactivity.

  • TOWARDS EXPLAINABLE CLASSIFIERS USING THE COUNTERFACTUAL APPROACH - GLOBAL EXPLANATIONS FOR DISCOVERING BIAS IN DATA
    • Agnieszka Mikołajczyk
    • Michał Grochowski
    • Arkadiusz Kwasigroch
    2021 Full text Journal of Artificial Intelligence and Soft Computing Research

    The paper proposes summarized attribution-based post-hoc explanations for the detection and identification of bias in data. A global explanation is proposed, and a step-by-step framework on how to detect and test bias is introduced. Since removing unwanted bias is often a complicated and tremendous task, it is automatically inserted, instead. Then, the bias is evaluated with the proposed counterfactual approach. The obtained results are validated on a sample skin lesion dataset. Using the proposed method, a number of possible bias-causing artifacts are successfully identified and confirmed in dermoscopy images. In particular, it is confirmed that black frames have a strong influence on Convolutional Neural Network’s prediction: 22% of them changed the prediction from benign to malignant.

  • Towards Rational Biosurfactant Design—Predicting Solubilization in Rhamnolipid Solutions
    • Ilona Kłosowska-Chomiczewska
    • Adrianna Kotewicz-Siudowska
    • Wojciech Artichowicz
    • Adam Macierzanka
    • Agnieszka Głowacz-Różyńska
    • Patrycja Szumała
    • Krystyna Mędrzycka
    • Elżbieta Hallmann
    • Elena Karpenko
    • Christian Jungnickel
    2021 Full text MOLECULES

    The efficiency of micellar solubilization is dictated inter alia by the properties of the solubilizate, the type of surfactant, and environmental conditions of the process. We, therefore, hypothesized that using the descriptors of the aforementioned features we can predict the solubilization efficiency, expressed as molar solubilization ratio (MSR). In other words, we aimed at creating a model to find the optimal surfactant and environmental conditions in order to solubilize the substance of interest (oil, drug, etc.). We focused specifically on the solubilization in biosurfactant solutions. We collected data from literature covering the last 38 years and supplemented them with our experimental data for different biosurfactant preparations. Evolutionary algorithm (EA) and kernel support vector machines (KSVM) were used to create predictive relationships. The descriptors of biosurfactant (logPBS, measure of purity), solubilizate (logPsol, molecular volume), and descriptors of conditions of the measurement (T and pH) were used for modelling. We have shown that the MSR can be successfully predicted using EAs, with a mean R2val of 0.773 ± 0.052. The parameters influencing the solubilization efficiency were ranked upon their significance. This represents the first attempt in literature to predict the MSR with the MSR calculator delivered as a result of our research.