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  • 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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
    • David Duenas-Cid
    2021 Pełny tekst

    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 Pełny tekst 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 Pełny tekst 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 6G Optical Fronthaul: A Survey on Enabling Technologies and Research Perspectives
    • Abdulhalim Fayad
    • Tibor Cinkler
    • Jacek Rak
    2021 IEEE Communications Surveys and Tutorials

    The anticipated launch of the Sixth Generation (6G) of mobile technology by 2030 will mark a significant milestone in the evolution of wireless communication, ushering in a new era with advancements in technology and applications. 6G is expected to deliver ultra-high data rates and almost instantaneous communications, with three-dimensional coverage for everything, everywhere, and at any time. In the 6G Radio Access Networks (RANs) architecture, the Fronthaul connects geographically distributed Remote Units (RUs) to Distributed/Digital Units (DUs) pool. Among all possible solutions for implementing 6G fronthaul, optical technologies will remain crucial in supporting the 6G fronthaul, as they offer high-speed, low-latency, and reliable transmission capabilities to meet the 6G strict requirements. This survey provides an explanation of the 5G and future 6G optical fronthaul concept and presents a comprehensive overview of the current state of the art and future research directions in 6G optical fronthaul, highlighting the key technologies and research perspectives fundamental in designing fronthaul networks for 5G and future 6G. Additionally, it examines the benefits and drawbacks of each optical technology and its potential applications in 6G fronthaul networks. This paper aims to serve as a comprehensive resource for researchers and industry professionals about the current state and future prospects of 6G optical fronthaul technologies, facilitating the development of robust and efficient wireless networks of the future.

  • Toward Intelligent Recommendations Using the Neural Knowledge DNA
    • Guangjian Ning
    • Chunwang Wu
    • Haoxi Zhang
    • Edward Szczerbicki
    2021 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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 Pełny tekst 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.

  • Towards Scalable Simulation of Federated Learning
    • Tomasz Kołodziej
    • Paweł Rościszewski
    2021 Communications in Computer and Information Science

    Federated learning (FL) allows to train models on decentralized data while maintaining data privacy, which unlocks the availability of large and diverse datasets for many practical applications. The ongoing development of aggregation algorithms, distribution architectures and software implementations aims for enabling federated setups employing thousands of distributed devices, selected from millions. Since the availability of such computing infrastructure is a big barrier to experimenting with new approaches, we claim that efficient simulation of FL is necessary and propose the PaSSiFLora library for simulating FL clients in a cluster environment. In PaSSiFLora, the training algorithm is actually performed on real data, but each cluster node can simulate multiple FL clients. Because uniform random selection of clients results in poor simulation performance due to load imbalance, we propose to use uniform random selection of MultiClients. Each MultiClient runs on a single cluster node and in each training iteration is responsible for simulating several clients, selected from a set of local clients. Our experimental results based on the FEMNIST dataset show that PaSSiFLora is capable of simulating 1536 clients and has a good scalability on 48 cluster nodes, which reduces the average iteration time to 13.57 s, from 330.61 s in the case of one cluster node. The MultiClient architecture allows to improve the average performance by up to 75% while it does not cause significant differences in model accuracy during the training. Additionally, correctness of the training is verified against existing FL frameworks: LEAF and TFF.

  • Towards Understanding the Health Aspects of the Processing of Lignocellulosic Fillers
    • Aleksander Hejna
    • Mariusz Marć
    2021 Pełny tekst Proceedings

    Health and safety issues should be addressed during the development and investigation of the industrial processes. In order to develop a sustainable process and fully evaluate its benefits and drawbacks for its optimization, it is crucial to determine its impact on the surrounding environment. This study aimed to assess the emission of volatile organic compounds during the modification of lignocellulosic fillers with passive dosimetry. Two types of processes were investigated: diisocyanate treatment of commercial lignocellulosic fillers in a batch mixer and thermo-mechanical treatment of brewers’ spent grain using a twin-screw extruder. The presence of multiple terpenes and terpenoids was detected during the processing of fillers. The main compounds detected during modification were camphene, 3-carene, limonene, α-pinene, and cymenes. These compounds can show the irritating and allergic character, according to the Globally Harmonized System of Classification and Labelling of Chemicals, as well as NFPA 704: Standard System for the Identification of the Hazards of Materials for Emergency Response. Some of them are also characterized by relatively low values of flash point, even below 40 °C. Therefore, their emissions during the modification of cellulose materials should be carefully monitored, and proper precautions need to be taken.

  • Towards Use of OntoClean for Ontology Contextualization
    • Wojciech Waloszek
    2021 Pełny tekst Procedia Computer Science

    Ontologies are formal systems of concepts used to describe numerous domains of interest. Ontologies are usually very expressive, but it comes at a price of computationally expensive reasoning over them. In our previous work we discussed the possible performance benefits that can be obtained by decomposing an ontology into contexts. While the benefits are appealing, we discovered that, in our case, the main obstacle against using contextual versions of ontologies was the necessity of performing the costly process of their decomposition with the participation of human experts. In this paper we discuss the possibility of using OntoClean method for streamlining and at least partial automation of suggesting a decomposition of an ontology into contexts. We present a hypothesis about how to build a structure of contexts, and verify this hypothesis against several ontologies used in state-of-the-art research. The ontologies have been obtained by us in the process that uses elements of Systematic Literature Review. The final assessment of the method has been performed by human experts, during interviews, and we present the details of their evaluation in the paper.

  • Toxinas de setas
    • Roman Kotłowski
    2021

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  • Trace Metal Contamination of Bottom Sediments: A Review of Assessment Measures and Geochemical Background Determination Methods
    • Nicole Nawrot
    • Ewa Wojciechowska
    • Muhammad Mohsin
    • Suvi Kuittinen
    • Ari Pappinen
    • Shahabaldin Rezania
    2021 Pełny tekst Minerals

    This paper provides an overview of different methods of assessing the trace metal (TM) contamination status of sediments affected by anthropogenic interference. The geochemical background determination methods are also described. A total of 25 papers covering rivers, lakes, and retention tanks sediments in areas subjected to anthropogenic pressure from the last three years (2019, 2020, and 2021) were analysed to support our examination of the assessment measures. Geochemical and ecotoxicological classifications are presented that may prove useful for sediment evaluation. Among the geochemical indices, several individual pollution indices (CF, Igeo, EF, Pi (SPI), PTT), complex pollution indices (PLI, Cdeg, mCdeg, Pisum, PIAvg, PIaAvg, PIN, PIProd, PIapProd, PIvectorM, PINemerow, IntPI, MPI), and geochemical classifications are compared. The ecotoxicological assessment includes an overview of Sediment Quality Guidelines (SQG) and classifications introduced nationally (as LAWA or modified LAWA). The ecotoxicological indices presented in this review cover individual (ERi) and complex indices (CSI, SPI, RAC, PERI, MERMQ). Biomonitoring of contaminated sites based on plant bioindicators is extensively explored as an indirect method for evaluating pollution sites. The most commonly used indices in the reviewed papers were Igeo, EF, and CF. Many authors referred to ecotoxicological assessment via SQG. Moreover, PERI, which includes the toxic response index, was just as popular. The most recognised bioindicators include the Phragmites and Salix species. Phragmites can be considered for Fe, Cu, Cd, and Ni bioindication in sites, while Salix hybrid cultivars such as Klara may be considered for phytostabilisation and rhizofiltration due to higher Cu, Zn, and Ni accumulation in roots. Vetiveria zizanoides demonstrated resistance to As stress and feasibility for the remediation of As. Moreover, bioindicators offer a feasible tool for recovering valuable elements for the development of a circular economy (e.g., rare earth elements).

  • Tracking Fluorescent Dye Dispersion from an Unmanned Aerial Vehicle
    • Paweł Burdziakowski
    • Piotr Zima
    • Paweł Wielgat
    • Dominika Kalinowska
    2021 Pełny tekst SENSORS

    Commercial unmanned aerial vehicles continue to gain popularity and their use for collecting image data and recording new phenomena is becoming more frequent. This study presents an effective method for measuring the concentration of fluorescent dyes (fluorescein and Rhodamine WT) for the purpose of providing a mathematical dispersion model. Image data obtained using a typical visible-light camera was used to measure the concentration of the dye floating on water. The reference measurement was taken using a laboratory fluorometer. The article presents the details of three extensive measurement sessions and presents elements of a newly developed method for measuring fluorescent tracer concentrations. The said method provides tracer concentration maps presented on the example of an orthophoto within a 2 × 2 m discrete grid.

  • Transcriptomic landscape of blood platelets in healthy donors
    • Anna Supernat
    • Marta Popęda
    • Krzysztof Pastuszak
    • Myron G Best
    • Peter Gresner
    • Sjors In ‘t Veld
    • Bartłomiej Siek
    • Natalia Bednarz-Knoll
    • Matthew T. Rondina
    • Tomasz Stokowy
    • Thomas Würdinger
    • Jacek Jassem
    • Anna Żaczek
    2021 Pełny tekst Scientific Reports

    BACKGROUND Blood platelet RNA-sequencing is increasingly used among the scientific community. Aberrant platelet transcriptome is common in cancer or cardiovascular disease, but reference data on platelet RNA content in healthy individuals are scarce and merit complex investigation. METHODS We sought to explore the dynamics of platelet transcriptome. Datasets from 204 healthy donors were used for the analysis of splice variants, particularly with regard to age, sex, blood storage time, unit of collection or library size. RESULTS Genes B2M, PPBP, TMSB4X, ACTB, FTL, CLU, PF4, F13A1, GNAS, SPARC, PTMA, TAGLN2, OAZ1 and OST4 demonstrated the highest expression in the analysed cohort, remaining substantial transcription consistency. CSF3R gene was found upregulated in males (fold change 2.10, FDR q<0.05). Cohort dichotomisation according to the median age, showed upregulated KSR1 in the older donors (fold change 2.11, FDR q<0.05). Unsupervised hierarchical clustering revealed two clusters which were irrespective of age, sex, storage time, collecting unit or library size. However, when donors are analysed globally (as vectors), sex, storage time, library size, the unit of blood collection as well as age impose a certain degree of between- and/or within-group variability. CONCLUSIONS Separately analysed platelet splice variants retain general consistency, with a few interesting deviating genes from these general trends. On the other hand, the multidimensional analysis revealed statistically significant variability between and within the analysed groups. Our work provides a reference for studies working both on healthy platelets and pathological conditions affecting platelet transcriptome.

  • Transformation of polyvinyl chloride (PVC) into a versatile and efficient adsorbent of Cu(II) cations and Cr(VI) anions through hydrothermal treatment and sulfonation
    • Xianbao Xu
    • Daan Zhu
    • Xiaonuan Wang
    • Liling Deng
    • Xinyun Fan
    • Zizhen Ding
    • Ai Zhang
    • Gang Xue
    • Yanbiao Liu
    • Weimin Xuan
    • Xiang Li
    • Jacek Mąkinia
    2021 Pełny tekst JOURNAL OF HAZARDOUS MATERIALS

    The reuse of waste polyvinyl chloride (PVC) has drawn much attention as it can reduce plastic waste and associated pollution, and provide valuable raw materials and products. In this study, sulfonated PVC-derived hydrochar (HS-PVC) was synthesized by two-stage hydrothermal treatment (HT) and sulfonation, and shown to be a versatile adsorbent. The reoval of Cu(II) cations and Cr(VI) anions using HS-PVC reached 81.2 ± 1.6% and 60.3 ± 3.8%, respectively. The first stage of HT was crucial for the dichlorination of PVC and the formation of an aromatic structure. This stage guaranteed the introduction of -SO3H onto PVC-derived hydrochar through subsequent sulfonation. HT intensities (i.e., temperature and time) and sulfonation intensity strongly determined the adsorption capacity of HS-PVC. Competitive adsorption between Cu(II) and Cr(VI) onto HS-PVC was demonstrated by binary and preloading adsorption. The proposed Cu(II) cations adsorption mechanism was electrostatic adsorption, while Cr(VI) were possibly complexed by the phenolic -OH and reduced to Cr(III) cations by C=C groups in HS-PVC. In addition, HS-PVC derived from PVC waste pipes performed better than PVC powder for Cu(II) and Cr(VI) removal (＞90%). This study provides an efficient method for recycling waste PVC and production of efficient adsorbents.

  • Transformation of the Odesa Waterfront
    • Piotr Lorens
    • Andrii Polishchuk
    2021 Pełny tekst Przestrzeń Ekonomia Społeczeństwo

    Odesa is a unique city: it is the third-largest city in Ukraine and the second in the Black sea region. During its short but eventful history, it gathered a variety of cultural layers within its boundaries, what had reflected in its architecture, urban life, and unique accent of its inhabitants. The city`s waterfront is considered to be the Pearl of the Black Sea. Starting with the receiving of the Porto Franco status in 1819, Odesa was the economic nexus and the symbol of entrepreneurship in the Russian Empire. During the Soviet period, city and port expanded to reach the goals of the communist era. The paradigm shift in economic realms related to the transformation of the economy at the beginning of the 1990s shed light on the city's weaknesses. Water and air pollution, large industrial zones in the sea façade of the city, and lack of high-level infrastructure for tourists had transformed the image of Odesa into a regular post-soviet town in the conditions of the market economy. On the other hand, the newborn post-soviet and postindustrial citizens of Odesa have different priorities and do not necessarily think about the spatial problems. A comprehensive study, using the observations, literature review, and interviews, was conducted to describe the influence of the social realm on an urban form of the Waterfront. The result of the analysis supports the hypothesis of the study: the trajectories of the social, economic, and spatial development of the Odesa waterfront are not correlating with each other. Within this paper the possible scenarios and prospects for transformation of the urban waterfront of Odesa are discussed on the basis of the wider perspective of reshaping the post-soviet waterfronts

  • Transforming a Traditional, Family-Run Car Dealership into a Digital-Era Modern Service Provider
    • Sławomir Ostrowski
    2021 Pełny tekst

    The automotive industry today faces multiple challenges. The automotive market is characterised by frequent changes and technological developments in comfort and safety of travel by all types of vehicles. The division between traditional and modern services is related to their susceptibility to technological progress. We should differentiate between two types of technology: technology used directly in vehicles and technology utilized in the delivery of products and services, which is transforming today’s automotive sales. It is the technological sphere that has contributed to numerous changes, the cumulative effect of which affects the perception of services as ‘modern’. Nowadays, customers expect a modern approach to sales, including the possibility of transferring the car sales process to the Internet, a virtual world in which, in the 21st century, state-of-the-art, immediately accessible solutions are expected. It is thus necessary to move traditional automotive sales online (always accessible location) in order to create a more convenient way of buying a car, regardless of restrictions such as those that emerged due to the outbreak of pandemic. This article presents a pilot study conducted in a family business specialising in the sale of new and second-hand cars. The study revealed a need to change car sales processes over the next few years and introduce modern automotive services. Purchasing a new or second-hand vehicle online no longer seems like a distant future.

  • Transparency of publicly available information about fiscal and monetary policy in Poland
    • Maria Jastrzębska
    2021 Pełny tekst

    Research background: The quality of information provided by fiscal and monetary authorities are important in a democratic state. Ensuring fiscal policy transparency reduces fiscal risk and corruption and promotes public acceptance of fiscal reforms. Ensuring transparency in monetary policy allows market participants to anticipate central bank responses and take their effects into account when making investment and consumption decisions. Aim of the article: The aim of the article is to evaluate the transparency of information provided to the public by the fiscal and monetary authorities in Poland in the light of international standards of fiscal and monetary policy transparency and to propose changes to increase it. Methods: Qualitative analysis, deductive and inductive reasoning were used. The assessment of the level of transparency of publicly available information on fiscal and monetary policy in Poland was based on the analysis of the implementation of good practices formulated by the International Monetary Fund and the open budget index calculated by the International Budget Partnership. Findings and added value: There are no publications in the national literature dealing with the transparency of publicly available information on fiscal and monetary policies in the context of coordination of these policies. Poland lacks transparent message about public finance, with particular emphasis on the state budget, which would allow citizens to control the government's fiscal policy actions. There is a lack of transparent information about the operations of the NBP in relation to the government. There is a lack of clear, reliable and complete information for citizens about the coordination of actions taken by the fiscal and monetary authorities in Poland to achieve specific objectives of the state's financial policy.

  • Trends shaping innovations in the aerosol market
    • Norbert Piotrowski
    2021 Pełny tekst World Aerosols. The Voice of the Aerosol Industry

    New hygiene regimes and sustainability commitments are helping to shape the aerosol market. Norbert Piotrowski of Aerosol Service Poland explains the thinking behind the company’s latest hygiene innovations.

  • Triazoloacridone C-1305 impairs XBP1 splicing by acting as a potential IRE1α endoribonuclease inhibitor
    • Sylwia Bartoszewska
    • Jarosław Króliczewski
    • David Crossman
    • Aneta Pogorzelska
    • Maciej Bagiński
    • James F. Collawn
    • Rafal Bartoszewski
    2021 Pełny tekst CELLULAR & MOLECULAR BIOLOGY LETTERS

    Inositol requiring enzyme 1 alpha (IRE1α) is one of three signaling sensors in the unfolding protein response (UPR) that alleviates endoplasmic reticulum (ER) stress in cells and functions to promote cell survival. During conditions of irrevocable stress, proapoptotic gene expression is induced to promote cell death. One of the three signaling stressors, IRE1α is an serine/threonine-protein kinase/endoribonuclease (RNase) that promotes nonconventional splicing of XBP1 mRNA that is translated to spliced XBP1 (XBP1s), an active prosurvival transcription factor. Interestingly, elevated IRE1α and XBP1s are both associated with poor cancer survival and drug resistance. In this study, we used next-generation sequencing analyses to demonstrate that triazoloacridone C-1305, a microtubule stabilizing agent that also has topoisomerase II inhibitory activity, dramatically decreases XBP1s mRNA levels and protein production during ER stress conditions, suggesting that C-1305 does this by decreasing IRE1α’s endonuclease activity.

  • Tripping of F-type RCDs for high-frequency residual currents
    • Hanan Tariq
    • Stanisław Czapp
    2021

    Residual current devices (RCDs) are apparatus commonly used for protection against electric shock in low-voltage electrical installations. They protect people in the case of an earth fault or even in the case of direct contact with the live parts. However, to be effective protective devices, RCDs have to detect residual currents of various waveform shapes which appear in modern electrical installations. For this purpose, RCDs are classified into four types: AC; A; F and B. This paper is focused on F-type RCDs provided for the detection, in particular, of mixed-frequency residual currents. According to the standard referring to the F-type RCDs, they are tested by manufacturers under the non-sinusoidal waveform having components generated by control equipment supplied from a single-phase. In this paper, results of two tripping tests (other than normative) of F-type RCDs are presented. During the first test, waveforms having components generated by control equipment supplied from three phases were forced. During the second test, high-frequency pure sinusoidal residual currents were generated. Results of these tests have shown that F-type RCDs may detect mixed-frequency residual currents other than the normative but may not react to sinusoidal currents of frequencies higher than 1 kHz.

  • Tunable Dielectric Switching of (Quinuclidinium)[MnCl4] Hybrid Compounds
    • Natalia Wójcik
    • Dorota A. Kowalska
    • Monika Trzebiatowska
    • Ewelina Jach
    • Adam Ostrowski
    • Waldemar Bednarski
    • Marek Gusowski
    • Piotr Staniorowski
    • Agnieszka Ciżman
    2021 Pełny tekst Journal of Physical Chemistry C

    Inorganic−organic hybrid QMnCl (Q = quinuclidinium) crystals were synthesized and characterized. The X-ray and variable-temperature IR/Raman analysis demonstrate that the crystals undergo a reversible structural phase transition, which originates from an order−disorder process and is related to the dynamics of the organic Q cation. Dielectric function measurements disclose a switchability between low (“OFF”) and high (“ON”) dielectric states centered at around 285 K. Owing to a remarkable temperature-dependent dielectric function, this type of molecular compound can represent an interesting tunable and switchable dielectric material for a diverse range of applications.

  • Two bacterial small heat shock proteins, IbpA and IbpB, form a functional heterodimer
    • Artur Piróg
    • Francesca Cantini
    • Łukasz Nierzwicki
    • Igor Obuchowski
    • Bartłomiej Tomiczek
    • Jacek Czub
    • Krzysztof Liberek
    2021 Pełny tekst JOURNAL OF MOLECULAR BIOLOGY

    Small heat shock proteins (sHsps) are a conserved class of ATP-independent chaperones which in stress conditions bind to unfolded protein substrates and prevent their irreversible aggregation. Substrates trapped in sHsps-containing aggregates are efficiently refolded into native structures by ATP-dependent Hsp70 and Hsp100 chaperones. Most γ-proteobacteria possess a single sHsp (IbpA), while in a subset of Enterobacterales, as a consequence of ibpA gene duplication event, a two-protein sHsp (IbpA and IbpB) system has evolved. IbpA and IbpB are functionally divergent. Purified IbpA, but not IbpB, stably interacts with aggregated substrates, yet both sHsps are required to be present at the substrate denaturation step for subsequent efficient Hsp70-Hsp100-dependent substrate refolding. IbpA and IbpB interact with each other, influence each other’s expression levels and degradation rates. However, the crucial information on how these two sHsps interact and what is the basic building block required for proper sHsps functioning was missing. Here, based on NMR, mass spectrometry and crosslinking studies, we show that IbpA-IbpB heterodimer is a dominating functional unit of the two sHsp system in Enterobacterales. The principle of heterodimer formation is similar to one described for homodimers of single bacterial sHsps. β-hairpins formed by strands β5 and β7 of IbpA or IbpB crystallin domains associate with the other one's β-sandwich in the heterodimer structure. Relying on crosslinking and molecular dynamics studies, we also propose the orientation of two IbpA-IbpB heterodimers in a higher order tetrameric structure.

  • Two complementary approaches for the synthesis and isolation of stable phosphanylphosphaalkenes
    • Aleksandra Ziółkowska
    • Natalia Szynkiewicz
    • Łukasz Ponikiewski
    2021 Pełny tekst Inorganic Chemistry Frontiers

    Phospha-Wittig (phosphanylphosphinidene titanium(IV) complex) and phospha-Peterson (lithiated diphosphane) reactions were used to obtain phosphanylphosphaalkenes with the general formula XYC=P-PtBu2 (X = alkyl, aryl group or H; Y = alkyl or aryl group). Therefore, two series of reactions with different ketones and aldehydes were performed. An examination revealed that the two methods are complementary. For smaller carbonyl compounds, the phospha-Wittig reaction was shown to be a much better method, while for larger substituents (mainly aromatic), the phospha-Peterson reaction was shown to be a reliable method. These studies led to, among other things, the isolation of seven phosphanylphosphaalkenes in crystalline form after the phospha-Peterson reaction: (Ph)2C=P-PtBu2 (3a), Z-(Ph)(4-CN-Ph)C=P-PtBu2 (3c), (4-CN-Ph)2C=P-PtBu2 (3d), (4-MeO-Ph)2C=P-PtBu2 (3e), E-tBu(Ph)C=P-PtBu2 (3f), E-{(Me)2N-Ph}(H)C=P-PtBu2 (4d) and E-PhPh(H)C=P-PtBu2 (4e). Corresponding compounds were obtained at high yields under mild conditions, and more importantly, these new species are relatively air- and absolutely moisture-stable, especially these originating from aldehydes aldehyde. Additionally, a comprehensive DFT study helped us to establish not only the key factors crucial for the effective phospha-Wittig-based synthesis of C=P-P species but also the consecutive steps along the reaction path leading to the formation of these compounds.

  • Two-photon microperimetry with picosecond pulses
    • Marcin Marzejon
    • Łukasz Kornaszewski
    • Jakub Bogusławski
    • Piotr Ciąćka
    • Miłosz Martynow
    • Grażyna Palczewska
    • Sebastian Maćkowski
    • Krzysztof Palczewski
    • Maciej Wojtkowski
    • Katarzyna Komar
    2021 Pełny tekst Biomedical Optics Express

    Two-photon vision is a phenomenon associated with the perception of short pulsesof near-infrared radiation (900-1200 nm) as a visible light. It is caused by the nonlinear processof two-photon absorption by visual pigments. Here we present results showing the influence ofpulse duration and repetition rate of short pulsed lasers on the visual threshold. We comparedtwo-photon sensitivity maps of the retina obtained for subjects with normal vision using acost-effective fiber laser (λc=1028.4 nm,τp=12.2 ps,Frep=19.17 MHz) and a solid-state laser(λc=1043.3 nm,τp=0.253 ps,Frep=62.65 MHz). We have shown that in accordance with thedescription of two-photon absorption, the average optical power required for two-photon visionfor a fiber laser is 4 times greater than that for a solid-state laser. Mean sensitivity measured forthe first one is 5.9±2.8 dB lower than for the second but still 17 dB away from the safety limit,confirming that picosecond light sources can be successfully applied in microperimetry. Thisdevelopment would dramatically reduce the cost and complexity of future clinical devices

  • Two-Row ESPAR Antenna with Simple Elevation and Azimuth Beam Switching
    • Mateusz Rzymowski
    • Łukasz Kulas
    2021 Pełny tekst IEEE Antennas and Wireless Propagation Letters

    In this letter, we propose a two-row electronically steerable parasitic array radiator (ESPAR) antenna designed for direction of arrival (DoA) estimation in Internet of Things (IoT) applications relying on simple microcontrollers. The antenna is capable of elevation and azimuth beam switching using a simple microcontroller-oriented steering circuit and provides 18 directional radiation patterns, which can be grouped in 3 distinctive sets having different directions in the elevation. For each elevation direction, there are 6 different beam configurations that cover 360 degrees in the horizontal plane. Measurements of the realized antenna prototype carried out in an anechoic chamber show good agreement with numerical simulations. The antenna prototype provides low side lobe level (SLL), low half power beam width (HPBW) in both elevation and horizontal directions, and exhibit monotonous drop from the maximum value for all 18 radiation patterns. Therefore, the antenna is a good candidate for IoT nodes capable of DoA estimation in situations when radio frequency (RF) signals are impinging the antenna from different directions in elevation.

  • Two-step synthesis of niobium doped Na–Ca–(Mg)–P–Si–O glasses
    • Natalia Wójcik
    • S Ali
    • Aleksandra Mielewczyk-Gryń
    • B Jonson
    2021 Pełny tekst JOURNAL OF MATERIALS SCIENCE

    Niobium doped biosolubility glasses in the Na–Ca–(Mg)–P–Si–O system were prepared by using an untypical two-step synthesis route. The parent glass was melted in air atmosphere at 1350 °C followed by re-melting the glass in Nb crucible with the addition of metallic Mg/Ca powder in the nitrogen atmosphere. The second melting step was carried out at 1450–1650 °C, using an induction furnace. The topography and structure of the obtained glasses were characterized by confocal microscopy, X-ray powder diffraction and infrared spectroscopic techniques. The chemical compositions were examined by energy-dispersive X-ray spectroscopy (EDS). The glasses were found to be of grayish color, X-ray amorphous and having network connectivity between * 2.5 and 2.7. The network connectivity of re-melted glasses was lower than the one of the parent glass. The glass structure consists of a highly disrupted silicate network of predominantly Q2 groups as well as isolated orthophosphate tetrahedra. The parent glass contains nanocrystallites consisted of apatitic PO43- groups. The re-melted glasses contain nonapatitic or amorphous calcium phosphates. The obtained glass transition temperatures range from 530 to 568 °C and exhibit higher values for glassed doped with Ca metal. These glasses have improved thermal stability as compared to reference bioglasses. The biosolubility test in phosphate buffered saline solution (PBS) confirms that the glasses have biosolubility properties and HAp formation on the surfaces was observed

  • Twórczość - przekraczanie dyscyplin. Analiza postawy autorskiej
    • Agnieszka Kurkowska
    2021 Pełny tekst Facta Ficta. Journal of Theory, Narrative & Media

    Agnieszka Kurkowska w artykule Twórczość - przekraczanie dyscyplin. Analiza postawy autorskiej odnosi się do zagadnienia poruszania w różnych obszarach wiedzy i umiejętności przez jednostkowego twórcę. Zarysowany jest problem niemożności wąskiego traktowania architektury jako dziedziny stricte inżynieryjnej. Architekt otwarty na otaczające problemy przestrzenne, ich fizyczne i pozafizyczne aspekty sięga w swoich wypowiedziach do obszarów pokrewnych architekturze, aby swoją wypowiedź wzmocnić i wzbogacić. W poniższej pracy podjęto próbę udowodnienia tezy, że przeanalizowana tu postawa autorska ukazuje konieczność przekraczania dyscyplin w projektowaniu architektonicznym. Ukazano, w oparciu o studium przypadku, w jaki sposób poruszanie się poza ścisła inżynierią może wzbogacać projekty architekta i wzmacniać możliwość ich oddziaływania. Na dobrane do prezentowanej analizy projekty składają się projekty obiektów architektonicznych, projekty małej architektury, mebli, przedmiotów użytkowych, wnętrz. To również projekty artystyczne posiłkujące się malarstwem, grafiką, rzeźbą, fotografią czy instalacją przestrzenną, także publikacje książkowe. Kolejną kategorią są projekty edukacyjne skoncentrowane na cyklach działań warsztatowych, materiałach edukacyjnych, wydarzeniach partycypacyjnych. Wszystkie przykłady łączy osoba autora, poruszającego się w swojej pracy w obszarze kilku dyscyplin, co w perspektywie czasowej ukazuje kompletną, wieloelementową postawę wobec przestrzeni, korzystających z niej ludzi i wypełniających ją obiektów. Wspomniana postawa zawiera kilka istotnych komponentów, które przeważając w określonych przypadkach, przenoszą go do poszczególnych zadań i związanych z nimi ról społecznych i zawodowych. Bywa więc architekt twórcą, gdy posługuje się narzędziami wyrazu artystycznego, kreując indywidualne, unikalne obiekty w różnej skali, poruszając się jednocześnie w obszarze sztuki i inżynierii. Może też być naukowcem, czy badaczem analizujący, pogłębiający, poszukującym, weryfikujący przyjęte rozwiązania. Czasami staje się pedagogiem czy edukatorem, gdy swoje działania skupia na przekazaniu wiedzy. Ponad wszystko architekt pozostaje jednakże człowiekiem o określonej strukturze psychicznej i fizycznej, będąc osobowym elementem społeczności. Architekt to autor przekraczający różne dyscypliny w ramach swojej twórczości czego konieczności i celowości mają dowieść przedstawione analizy i wspierające je studium przypadku.

  • Type III Responses to Transient Inputs in Hybrid Nonlinear Neuron Models
    • Jonathan E. Rubin
    • Justyna Signerska-Rynkowska
    • Jonathan D. Touboul
    2021 Pełny tekst SIAM JOURNAL ON APPLIED DYNAMICAL SYSTEMS

    Experimental characterization of neuronal dynamics involves recording both of spontaneous activity patterns and of responses to transient and sustained inputs. While much theoretical attention has been devoted to the spontaneous activity of neurons, less is known about the dynamic mechanisms shaping their responses to transient inputs, although these bear significant physiological relevance. Here, we study responses to transient inputs in a widely used class of neuron models (nonlinear adaptive hybrid models) well-known to reproduce a number of biologically realistic behaviors. We focus on responses to transient inputs that have been previously associated with Type III neurons, arguably the least studied category in Hodgkin's classification, which are those neurons that never exhibit continuous firing in response to sustained excitatory currents. The two phenomena that we study are postinhibitory facilitation, in which an otherwise subthreshold excitatory input can induce a spike if it is applied with proper timing after an inhibitory pulse, and slope detection, in which a neuron spikes to a transient input only when the input's rate of change is in a specific, bounded range. Using dynamical systems theory, we analyze the origin of these phenomena in nonlinear hybrid models. We provide a geometric characterization of dynamical structures associated with postinhibitory facilitation in the system and an analytical study of slope detection for tent inputs. While the necessary and sufficient conditions for these behaviors are easily satisfied in neurons with Type III excitability, our proofs are quite general and valid for neurons that do not exhibit Type III excitability as well. This study therefore provides a framework for the mathematical analysis of these responses to transient inputs associated with Type III neurons in other systems and for advancing our understanding of these systems' computational properties.

  • Typology and comparative analysis of black tents built in tradition of iranian tribes
    • Najmeh Hassas
    2021 Pełny tekst

    This study focused on the habits and way of life of nomads in the Iranian Highlands, but their homes, called Black Tents, were of the main interest. The research explored the construction of the Black Tents and the way of shaping the space in which family life takes place. It concerned the architectural forms of tents, structures and materials from which they are erected, as well as interior furnishings and objects that determine their character. The methods used in the research include descriptive analysis and graphical presentation of the test results. The inquiry was conducted in libraries, archives and institutions and using official websites. The author also conducted drawing and photographic inventories of tents and everyday life of nomads. Laboratory tests of the next phase of work have been documented with printouts and presentations of the sets of devices used in the research. Further analysis was carried out using advanced software computer programmes, such as 3DMax, ABAQUS and other professional civil engineering digital tools allowing to obtain comparable results. The research results and summaries of their individual phases are presented in the form of maps, charts and tables. As a result of macroscopic studies, it turned out that the fabric, made of cloth woven from long black goat hair, with which the structures are covered (Chador), which is woven by women, is the same for all tribes. Women also erect and dismantle tents before and after the journey and so have an influence on their construction. The analysis of the dimensions and forms of the discussed seven types of tents from different parts of the country showed large differences, which is evidence of creativity and engineering thinking. The next step of the research was to check to what extent the stability of each tent is adjusted to the climatic situation in which it is used. For this purpose, models were created in the ABACUS program. Their responses to wind and rain loads have been studied. It has been confirmed that the tents are strictly adapted to the conditions in which they are used. Their diversification is the result of the experience of many generations of nomads: observing the routes they traveled and the materials they could use. Tests of tent models covered with hand-made goat hair fabric showed that it is more useful for strengthening the structure of the tent and protecting its interior than fabrics used today for a similar purpose.

  • UAV Photogrammetry under Poor Lighting Conditions—Accuracy Considerations
    • Paweł Burdziakowski
    • Katarzyna Bobkowska
    2021 Pełny tekst SENSORS

    The use of low-level photogrammetry is very broad, and studies in this field are conducted in many aspects. Most research and applications are based on image data acquired during the day, which seems natural and obvious. However, the authors of this paper draw attention to the potential and possible use of UAV photogrammetry during the darker time of the day. The potential of night-time images has not been yet widely recognized, since correct scenery lighting or lack of scenery light sources is an obvious issue. The authors have developed typical day- and night-time photogrammetric models. They have also presented an extensive analysis of the geometry, indicated which process element had the greatest impact on degrading night-time photogrammetric product, as well as which measurable factor directly correlated with image accuracy. The reduction in geometry during night-time tests was greatly impacted by the non-uniform distribution of GCPs within the study area. The calibration of non-metric cameras is sensitive to poor lighting conditions, which leads to the generation of a higher determination error for each intrinsic orientation and distortion parameter. As evidenced, uniformly illuminated photos can be used to construct a model with lower reprojection error, and each tie point exhibits greater precision. Furthermore, they have evaluated whether commercial photogrammetric software enabled reaching acceptable image quality and whether the digital camera type impacted interpretative quality. The research paper is concluded with an extended discussion, conclusions, and recommendation on night-time studies.

  • Uczelnia organizacją z domieszka turkusu - sznasa czy iluzja?
    • Krzysztof Leja
    • Aleksandra Pawlak
    2021 Pełny tekst e-mentor

    Po kilkuletnich dyskusjach nad przyszłym kształtem szkolnictwa wyższego w Polsce, zarówno na poziomie systemowym, jak i instytucjonalnym, w 2018 r. uchwalono ustawę Prawo o szkolnictwie wyższym i nauce, zwaną dalej Ustawą (2018). Regulacja ta wraz z pakietem rozporządzeń poszerzyła autonomię uczelni w zakresie organizacyjno-zarządczym, jednocześnie potęgując znaczenie ich rozliczalności. Wzmocnienie władzy rektora spowodowało zmianę postrzegania uczelni jako organizacji rozproszonych (Weick, 1976) w kierunku organizacji zwartych (Brunsson i Sahlin-Andersson, 2000) Autorzy opracowania dostrzegli, że koncepcja uczelni, zgodnie z literą i duchem Ustawy, nie zwraca należytej uwagi na relacje między pracownikami. Dlatego za cel artykułu uznano przedstawienie propozycji wdrożenia do instytucji akademickiej elementów coraz częściej opisywanej w literaturze naukowej – a równocześnie budzącej skrajne emocje – koncepcji organizacji turkusowej (Laloux, 2015). W artykule wskazano niewykorzystane, zdaniem autorów, możliwości zmian organizacyjno-zarządczych, jakie stworzyła Ustawa, a także opisano wybrane cechy organizacji turkusowej, odnosząc je do instytucji akademickiej. Ponadto zestawiono cechy uniwersytetu tradycyjnego, przedsiębiorczego oraz uniwersytetu z domieszką turkusu. W części badawczej przeanalizowano wywiady przeprowadzone z celowo wybranymi pracownikami Politechniki Gdańskiej, którzy wyrażali opinie dotyczące nowych rozwiązań organizacyjno-zarządczych zaproponowanych przez współautorkę artykułu podczas wywiadów. W podsumowaniu starano się odpowiedzieć na pytanie sformułowane w tytule.

  • Uczelnie kształcące polskich inżynierów elektryków do II wojny światowej
    • Dariusz Świsulski
    2021 Pełny tekst Przegląd Elektrotechniczny

    Na podstawie notek biograficznych ponad 1000 osób przedstawiono uczelnie, w których wykształcenie w latach 1891-1935 zdobywali polscy inżynierowie elektrycy. Do I wojny światowej były to uczelnie zagraniczne: niemieckie, rosyjskie, francuskie, belgijskie. Później Polacy kształcili się w polskich uczelniach: Politechnice Lwowskiej oraz w utworzonej w 1915 roku i szybko rozwijającej się Politechnice Warszawskiej.

  • Ukrainian Market of Electrical Energy: Reforming, Financing, Innovative Investment, Efficiency Analysis, and Audit
    • Ruslan Kostyrko
    • Tetiana Kosova
    • Lidiia Kostyrko
    • Liudmyla Zaitseva
    • Oleksandr Melnychenko
    2021 Pełny tekst ENERGIES

    The aim of this research is to determine the influence of electrical energy market regulation reform in Ukraine on the competitive environment, the reproduction processes of financial and innovative support, and the energy efficiency of the national economy. The authors have put forward and verified the hypothesis that, under conditions of institutional maturity of the Ukrainian electrical energy market, its liberalization and separation of the kinds of activity related to generation, transmission, and distribution leads to a decrease in prices, and the level of economic concentration stimulates implementation of innovations and the formation of reports on sustainable development. Over the thirteen-year time interval, a steady trend of decreasing energy intensity of the Ukrainian economy was established, and the appropriateness of energy efficiency management based on strategic targets was substantiated. The electricity market model in Ukraine is defined as a hybrid one, with an emphasis on trade under bilateral agreements. It was statistically found that liberalization of the electrical energy market in Ukraine contributed to a decrease in prices, with the exception of the areas of largest household and non-household consumers. The high level of asset concentration in the accounts of large enterprises was revealed, and the conclusion concerning the improvement of the competitive environment in the electricity production sector and the existence of the features of natural monopolies in the areas of transmission and distribution of electricity was made. The assessment of the financial competitive ability and profitability of electrical energy market entities was made, the main entities of the investment activity and the sources of their financing were characterized, and innovations were emphasized. The role of the standards of the audit of integrated reporting of the Ukrainian energy holdings and their role in ensuring sustainable development was determined.