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Gdańsk University of Technology

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  • Classification of submandibular salivary stones based on ultrastructural studies
    • Dmitry Tretiakow
    • Andrzej Skorek
    • Joanna Wysocka
    • Kazimierz Darowicki
    • Jacek Ryl
    2021 ORAL DISEASES

    Introduction: Sialolithiasis remains a clinical problem with unclear etiopathogenesis, lack of prevention methods, and only surgical treatment. Materials and methods: An ultrastructure examination of submandibular sialoliths obtained from patients with chronic sialolithiasis was conducted using a scanning electron microscope and X‐ray photoelectron spectroscopy. Results: Based on the results, we divided sialoliths into three types: calcified (CAL), organic/lipid (LIP), and mixed (MIX). The core structure of the CAL and MIX is very similar. The core of the LIP has a prevalence of organic components. The intermediate layers’ structure of the CAL is different from LIP and MIX. In LIP and MIX, the organic component begins to increase in intermediate layers rapidly. The structure of the superficial layers for all types of sialoliths is similar. Conclusions: We introduced a new classification of the submandibular salivary gland stones. Based on the results, it can be said that sialoliths type CAL and LIP have their separate path of origin and development, while MIX is formed as CAL stone, and the further pathway of their growth passes as LIP stones. Organic components were much more than inorganic in all layers of salivary gland stones, which highly prevents their dissolution in the patient's salivary gland duct.

  • Classifying Emotions in Film Music - A Deep Learning Approach
    • Tomasz Ciborowski
    • Szymon Reginis
    • Adam Kurowski
    • Dawid Weber
    • Bożena Kostek
    2021 Full text Electronics

    The paper presents an application for automatically classifying emotions in film music. A model of emotions is proposed, which is also associated with colors. The model created has nine emotional states, to which colors are assigned according to the color theory in film. Subjective tests are carried out to check the correctness of the assumptions behind the adopted emotion model. For that purpose, a statistical analysis of the subjective test results is performed. The application employs a deep convolutional neural network (CNN), which classifies emotions based on 30 s excerpts of music works presented to the CNN input using mel-spectrograms. Examples of classification results of the selected neural networks used to create the system are shown.

  • Clays as Inhibitors of Polyurethane Foams’ Flammability
    • Aleksander Hejna
    2021 Full text Materials

    Polyurethanes are a very important group of polymers with an extensive range of applications in different branches of industry. In the form of foams, they are mainly used in bedding, furniture, building, construction, and automotive sectors. Due to human safety reasons, these applications require an appropriate level of flame retardance, often required by various law regulations. Nevertheless, without the proper modifications, polyurethane foams are easily ignitable, highly flammable, and generate an enormous amount of smoke during combustion. Therefore, proper modifications or additives should be introduced to reduce their flammability. Except for the most popular phosphorus-, halogen-, or nitrogen-containing flame retardants, promising results were noted for the application of clays. Due to their small particle size and flake-like shape, they induce a “labyrinth effect” inside the foam, resulting in the delay of decomposition onset, reduction of smoke generation, and inhibition of heat, gas, and mass transfer. Moreover, clays can be easily modified with different organic compounds or used along with conventional flame retardants. Such an approach may often result in the synergy effect, which provides the exceptional reduction of foams’ flammability. This paper summarizes the literature reports related to the applications of clays in the reduction of polyurethane foams’ flammability, either by their incorporation as a nanofiller or by preparation of coatings.

  • Cloning, expression in Komagataella phaffii, and biochemical characterization of recombinant sequence variants of Pseudomonas sp. S9 GDSL-esterase
    • Monika Wicka-Grochocka
    • Hubert Cieśliński
    • Marta Wanarska
    2021 Full text Acta Biochimica Polonica

    Two recombinant Komagataella phaffii (formerly Pichia pastoris) yeast strains for production of two sequential variants of EstS9 esterase from psychrotolerant bacterium Pseudomonas sp. S9, i.e. αEstS9N (a two-domain enzyme consisting of a catalytic domain and an autotransporter domain) and αEstS9Δ (a single-domain esterase) were constructed. However, only one of recombinant K. phaffii strains, namely Komagataella phaffii X-33/pPICZαestS9Δ, allowed to successfully produce and secrete recombinant αEstS9Δ enzyme outside of the host cell. The purified αEstS9Δ esterase was active towards short-chain p-nitrophenyl esters (C2-C8), with optimal activity for the acetate (C2) ester. The single-domain αEstS9Δ esterase exhibits the highest activity at 60oC and pH 9.5. In addition, the enzyme retains 90% of its activity after 3 hour incubation at 70–90oC. What should be also noted is that αEstS9Δ esterase produced in the K. phaffii expression system has a much higher specific activity (0.069 U/mg of protein) than the recombinant EstS9Δ esterase produced in an E. coli expression system (0.0025 U/mg of protein) (Wicka et al., 2016, Acta Biochim Pol 63: 117–125. https://doi.org/10.18388/ abp.2015_1074).

  • Closed-Loop Control System Design for Wireless Charging of Low-Voltage EV Batteries with Time-Delay Constraints
    • Viktor Shevchenko
    • Bohdan Pakhaliuk
    • Janis Zakis
    • Oleksandr Veligorskyi
    • Jarosław Łuszcz
    • Oleksandr Husev
    • Oleksandr Lytvyn
    • Oleksandr Matiushkin
    2021 Full text ENERGIES

    This paper presents an inductive power transfer system on the basis of a double single- phase three-level T-type inverter and two split transmitting coils for constant current and constant voltage wireless charging of low-voltage light electric vehicle batteries with closed-loop control, considering time-delay communication constraints. An optimal control structure and a modified control strategy were chosen and implemented to the wireless power transfer system as a result of a review and analysis of existing solutions. The control system analysis and adjustment of the coefficients of the regulator using Laplace transform were performed. Our study addressed the behavior of the control system with different time delays as well as the dynamic response of the system. The detecting algorithm of a secondary coil was proposed, which ensured efficient system operation and increased the functionality, safety and usability of the device. The efficiency of energy transfer of 90% was reached at the transmitted power of 110 W, which is at the level of existing solutions considered in the article and opens the way to the commercialization of the proposed solution. Therefore, the feasibility of using a nonclassical multilevel inverter, together with split transmitting coils for wireless charging was confirmed.

  • Closer Look at the Uncertainty Estimation in Semantic Segmentation under Distributional Shift
    • Sebastian Cygert
    • Andrzej Czyżewski
    • Bartłomiej Wróblewski
    • Radosław Słowiński
    • Karol Woźniak
    2021 Full text

    While recent computer vision algorithms achieve impressive performance on many benchmarks, they lack robustness - presented with an image from a different distribution, (e.g. weather or lighting conditions not considered during training), they may produce an erroneous prediction. Therefore, it is desired that such a model will be able to reliably predict its confidence measure. In this work, uncertainty estimation for the task of semantic segmentation is evaluated under a varying level of domain shift: in a cross-dataset setting and when adapting a model trained on data from the simulation. It was shown that simple color transformations already provide a strong baseline, comparable to using more sophisticated style-transfer data augmentation. Further, by constructing an ensemble consisting of models using different backbones and/or augmentation methods, it was possible to improve significantly model performance in terms of overall accuracy and uncertainty estimation under the domain shift setting. The Expected Calibration Error (ECE) on challenging GTA to Cityscapes adaptation was reduced from 4.05 to the competitive value of 1.1. Further, an ensemble of models was utilized in the self-training setting to improve the pseudo-labels generation, which resulted in a significant gain in the final model accuracy, compared to the standard fine-tuning (without ensemble).o

  • Closer look into the structures of tetrabutylammonium bromide–glycerol-based deep eutectic solvents and their mixtures with water
    • Patrycja Makoś-Chełstowska
    • Renáta Chromá
    • Vasil Andruch
    2021 Full text JOURNAL OF MOLECULAR LIQUIDS

    In recent years, deep eutectic solvents (DES) and it’s mixture with water have become more and more attention as green solvents used in chemistry. However, there are only a few theoretical studies on the mechanisms of pure DES and DES-water complex formation. Therefore, the structural properties of tetrabutylammonium bromide–glycerol-based deep eutectic solvents and their mixtures with water have been investigated by means of Molecular Dynamics simulations. The obtained results indicate that three types of H-bonds exist in the pure DES structures, and all of these interactions play an important role in DES formation. In addition, between hydrogen bond donors (HBDs) and hydrogen bond acceptor (HBA) weaker non-bonded interactions, i.e. van der Waals exist, which also contribute to the formation of stable DES structures and to lower the melting point of DES compared to pure substances. The small addition of water to DES provides the formation of a stable complex, however, a further increase in water content (higher than 50% v/v) provide to the destruction of the most important hydrogen bonds (O–H···Br) in DES structure.

  • Coffee Silverskin as a Multifunctional Waste Filler for High-Density Polyethylene Green Composites
    • Aleksander Hejna
    • Mateusz Barczewski
    • Paulina Kosmela
    • Olga Mysiukiewicz
    • Anton Kuzmin
    2021 Full text Journal of Composites Science

    This work aims to describe the coffee silverskin effect as a lignocellulosic waste filler for high-density polyethylene (HDPE) composites development. The main task was to determine various modification effects resulting from the complex chemical composition of coffee silverskin containing compounds with potential antioxidative properties, including caffeine, polyphenols, tannins, or melanoidins. The processing, thermal, physicochemical, and thermomechanical properties of the HDPE-based composites with different filler content (1–20 wt%) were evaluated. Comprehensively realized thermomechanical analysis revealed the filler’s reinforcing effects on the HDPE matrix while defining problems with obtaining adequate adhesion in the interfacial area. At the same time, studies have shown a very beneficial effect of the silverskin addition on the thermal properties of composites, that even the smallest addition allows for a significant increase in the thermooxidative resistance of HDPE composites assessed using the oxidation induction time from 20 min for HDPE up to 140 min for the composites with 20 wt% of the filler. The obtained research results allow classifying the coffee silverskin waste filler, not only as a filler intended for the production of composites with a high degree of filling but also as an additive that significantly changes the properties of polyethylene in the case of using low concentrations. This can have a very beneficial impact on the development of novel wood polymer (WPC) and natural fiber composites (NFC).

  • Coffee silverskin as a potential bio-based antioxidant for polymer materials: Brief review
    • Aleksander Hejna
    2021 Full text Proceedings

    Coffee silverskin is one of the by-products generated by the coffee industry. Although it is not the most burdensome one, because it stands only for ~4.2 wt % of coffee, it seems like an auspicious raw material for industrial processes. Coffee silverskin is characterized by a relatively low moisture content of ~5–7%, so it often does not require quite energy-consuming drying processes. The chemical composition of coffee silverskin, as well as other renewable materials, may be significantly affected by its type and origin, in this case, plant Coffea. Nevertheless, due to high fiber content, it could be considered as exciting material for the manufacturing of wood polymer composites. At the same time, it contains noticeable amounts of proteins, which may provide additional features to polymer composites. However, what is most important is the high content of antioxidants, which could noticeably enhance their lifetime by inhibition of the oxidation reactions. In the presented paper, attempts of coffee silverskin incorporation into different polymer matrices were summarized and discussed. Moreover, potential future trends in this area of research were proposed.

  • Coffee Wastes as Sustainable Flame Retardants for Polymer Materials
    • Henri Vahabi
    • Maryam Jouyandeh
    • Thibault Parpaite
    • Mohammad Saeb
    • Seeram Ramakrishna
    2021 Full text Coatings

    Development of green flame retardants has become a core part of the attention of material scientists and technologists in a paradigm shift from general purpose to specific sustainable products. This work is the first report on the use of coffee biowastes as sustainable flame retardants for epoxy, as a typical highly flammable polymer. We used spent coffee grounds (SCG) as well as SCG chemically modified with phosphorus (P-SCG) to develop a sustainable highly efficient flame retardant. A considerable reduction in the peak of heat release rate (pHRR) by 40% was observed in the pyrolysis combustion flow calorimeter analysis (PCFC), which proved the merit of the used coffee biowastes for being used as sustainable flame retardants for polymers. This work would open new opportunities to investigate the impact of other sorts of coffee wastes rather than SCG from different sectors of the coffee industry on polymers of different family.

  • Cognitive Systems, Concepts, Processes, and Techniques for the Age of Industry 4.0
    • Edward Szczerbicki
    • Ngoc-Thanh Nguyen
    2021 Full text CYBERNETICS AND SYSTEMS

    The aim of this Guest Edition of Cybernetics and Systems is to present a wide-ranging scale of concepts and processes being currently researched, developed, and evaluated in real life settings in anticipation of incoming Industry 4.0 era. With the fourth industrial revolution expectation, the broad spectrum of cognitive approaches have emerged as an attempt to mimic and augment, in some way, human intelligence. Intelligence, in cognitive systems and computing, can be defined as the ability to learn from experience and use the domain of expert knowledge to adapt and act in contextually new situations. The communicated selection of papers does not postulate ultimate answers to the aspects of Industry 4.0 and cognitive systems that are discussed. Rather, it poses ideas and provokes for additional exploration. It also makes the reader aware of immensely multifaceted and interdisciplinary character of such predicaments.

  • Collision‐Aware Routing Using Multi‐Objective Seagull Optimization Algorithm for WSN‐Based IoT
    • Preetha Jagannathan
    • Sasikumar Gurumoorthy
    • Andrzej Stateczny
    • Parameshachari Bidare Divakarachar
    • Jewel Sengupta
    2021 Full text SENSORS

    In recent trends, wireless sensor networks (WSNs) have become popular because of their cost, simple structure, reliability, and developments in the communication field. The Internet of Things (IoT) refers to the interconnection of everyday objects and sharing of information through the Internet. Congestion in networks leads to transmission delays and packet loss and causes wastage of time and energy on recovery. The routing protocols are adaptive to the congestion status of the network, which can greatly improve the network performance. In this research, collision‐aware routing using the multi‐objective seagull optimization algorithm (CAR‐MOSOA) is designed to meet the efficiency of a scalable WSN. The proposed protocol exploits the clustering process to choose cluster heads to transfer the data from source to endpoint, thus forming a scalable network, and improves the performance of the CAR‐MOSOA protocol. The proposed CAR‐MOSOA is simulated and examined using the NS‐2.34 simulator due to its modularity and inexpensiveness. The results of the CAR‐MOSOA are comprehensively investigated with existing algorithms such as fully distributed energy‐aware multi‐level (FDEAM) routing, energy‐efficient optimal multi‐path routing protocol (EOMR), tunicate swarm grey wolf optimization (TSGWO), and CoAP simple congestion control/advanced (CoCoA). The simulation results of the proposed CAR‐MOSOA for 400 nodes are as follows: energy consumption, 33 J; endto‐end delay, 29 s; packet delivery ratio, 95%; and network lifetime, 973 s, which are improved compared to the FDEAM, EOMR, TSGWO, and CoCoA.

  • Colored Tattoo Ink Screening Method with Optical Tissue Phantoms and Raman Spectroscopy
    • Filip Sadura
    • Maciej Wróbel
    • Katarzyna Karpienko
    2021 Full text Materials

    Due to the increasing popularity of tattoos among the general population, to ensure their safety and quality, there is a need to develop reliable and rapid methods for the analysis of the composition of tattoo inks, both in the ink itself and in already existing tattoos. This paper presents the possibility of using Raman spectroscopy to examine tattoo inks in biological materials. We have developed optical tissue phantoms mimicking the optical scattering coefficient typical for human dermis as a substitute for an in vivo study. The material employed herein allows for mimicking the tattoo-making procedure. We investigated the effect of the scattering coefficient of the matrix in which the ink is located, as well as its chemical compositions on the spectra. Raman surface line scanning has been carried out for each ink in the skin phantom to establish the spatial gradient of ink concentration distribution. This ensures the ability to detect miniature concentrations for a tattoo margin assessment. An analysis and comparison of the spectra of the inks and the tattooed inks in the phantoms are presented. We recommend the utilization of Raman spectroscopy as a screening method to enforce the tattoo ink safety legislations as well as an early medical diagnostic screening tool.

  • COMBINATION OF ARCHITECTURAL, ENVIRONMENTAL, AND SOCIAL ASPECTS IN URBAN STORMWATER MANAGEMENT. A CASE STUDY OF THE UNIVERSITY CAMPUS
    • Ewa Wojciechowska
    • Magdalena Gajewska
    • Nicole Nawrot
    • Monika Kilanowska
    • Hanna Obarska-Pempkowiak
    2021 Full text International Journal of Conservation Science

    Increasing a city’s resilience against climate change is one of the major concerns of today. Sustainable stormwater management, using Green Infrastructure units (GI) integrated with an urban area, has proved to be effective in flooding control and to offer extra benefits encompassing groundwater recharge, stormwater treatment, mitigation of air pollution, and an urban micro-climate. Moreover, GI brings cultural benefits for the urban population. However, the “grey” solutions are still popular and widely accepted. This paper presents three conceptions of the revitalisation of a part of campus of the Gdansk University of Technology with different approaches to stormwater management. The first approach (“blue-grey”) is purely based on an architect’s vision, and has some negative aspects from the environmental point of view. The second approach (“blue-grey-green”) is a modification of the previous one, in an attempt to introduce green elements and to obtain more ecosystem services. The third conception (“blue-green”) is fundamentally different, as it relies on GI elements and attempts to respond to the needs reported by the local community of students and university employees accordingly to opinion polls that were conducted. The three solutions are discussed in terms of water sensibility, aesthetics, functionality, usability, and public perception.

  • Combination of hydrodynamic cavitation and SR-AOPs for simultaneous degradation of BTEX in water
    • Kirill Fedorov
    • Xun Sun
    • Grzegorz Boczkaj
    2021 CHEMICAL ENGINEERING JOURNAL

    Hydrodynamic cavitation (HC) is an emerging technology gaining interest in water treatment for use in elimination of a wide range of organic pollutants. The energy released during cavitation phenomenon has number of applications and, particularly, it can be utilized for activation of persulfate (PS) and peroxymonosulfate (PMS). In the present study, hybrid techniques: HC combined with persulfates – HC-PS and HC-PMS were tested for the degradation of BTEX in water. Studies on the effect of initial PS and PMS concentration showed that a molar ratio of the oxidant to BTEX equal to 5 is favorable for both cases. Thus, in 240 min HC-PS-5 process allowed to degrade 91.51%, 95.50%, 94.65%, 94.95% of benzene, toluene, ethylbenzene and o-xylene, respectively, while 90.85%, 94.50%, 94.36%, 93.07% of those compounds were degraded by HC-PMS-5. BTEX degradation pathway was proposed for HC-PS-5 and HC-PMS-5 processes relying on the identification of the main reaction intermediates using liquid chromatography coupled with UV diode array detector (HPLC-UV-DAD). Benzyl alcohol, phenol, benzoic acid, benzaldehyde and o-cresol were the main intermediates of BTEX degradation, which multistep pathway involved H-abstraction, OH addition and dealkylation in route to mineralization. At final time of treatment primary and secondary pollutants were effectively degraded. In terms of kinetics, BTEX degradation followed the pseudo-first-order reaction model and the degradation kinetics were faster in HC-PMS-5 system than in HC-PS-5. Surprisingly, the presence of chloride ions (Cl−) in HC-PMS-5 improved the degradation efficiency of alkylated benzene derivatives indicating a synergistic effect of Cl− with SO4•− radicals.

  • Combined effect of nitrogen-doped functional groups and porosity of porous carbons on electrochemical performance of supercapacitors
    • Anna Ilnicka
    • Malgorzata Skorupska
    • Mariusz Szkoda
    • Zuzanna Zarach
    • Piotr Kamedulski
    • Wojciech Zielinski
    • Jerzy P. Lukaszewicz
    2021 Full text Scientific Reports

    In this work, nitrogen-doped porous carbons obtained from chitosan, gelatine, and green algae were investigated in their role as supercapacitor electrodes. The effects of three factors on electrochemical performance have been studied— of the specific surface area, functional groups, and a porous structure. Varying nitrogen contents (from 5.46 to 10.08 wt.%) and specific surface areas (from 532 to 1095 m2g−1) were obtained by modifying the carbon precursor and the carbonization temperature. Doping nitrogen into carbon at a level of 5.74–7.09 wt.% appears to be the optimum for obtaining high electrochemical capacitance. The obtained carbons exhibited high capacitance (231 F g− 1 at 0.1 A g−1) and cycle durability in a 0.2 mol L−1 K2SO4 electrolyte. Capacitance retention was equal to 91% at 5 A g−1 after 10,000 chronopotentiometry cycles. An analysis of electrochemical behavior reveals the influence that nitrogen functional groups have on pseudocapacitance. While quaternary-N and pyrrolic-N nitrogen groups have an enhancing effect, due to the presence of a positive charge and thus improved electron transfer at high current loads, the most important functional group affecting energy storage performance is graphite-N/quaternary-N. The study points out that the search for the most favourable organic precursors is as important as the process of converting precursors to carbonbased electrode materials.

  • Combined environmental testing device for picosatellites
    • Adam Dąbrowski
    • Róża Pietruszewska
    • Szymon Krawczuk
    2021 Full text

    As access to space conditions becomes more available, both technically and economically, scientists’ interest in launching finer and more sophisticated experiments grows. To be qualified for launch, such experiments need to be carefully tested prior to the event. The tests should represent actual launch conditions as closely and in a detailed manner. Typical tests for payload include: vibration tests, thermal and vacuum tests, and sometimes shock tests. Acceleration tests with a centrifuge are rarely performed. In traditional static tests the load application tools are usually jacks or weights, in conjunction with a levers system to introduce forces on attachment points or pressure on surface pads. Alternative systems as air-bags are sometimes used. Such approaches are also notorious for their tendency to both over- and under-test at the same time. Furthermore, all these tests are performed separately, which disables study on any crosscorrelation effects, for example changing of stiffness of elements in changing temperature. A solution is suggested in combined environment testing device for picosatellites. A prototype has been successfully tested in the Large Diameter Facility. The aim of the device is to recreate as accurately as possible: dynamic, thermal and vacuum environment of a space rocket. The prototype hosted a 1U CubeSat dummy with sensors to measure various environments. Dynamic environment includes both high frequency but low amplitude vibrations as well as low frequency, quasi-stationary accelerations. This has been achieved by placing a custom designed shaker table inside the centrifuge. By controlling centrifuge, high amplitude, quasi-stationary rocket acceleration can be recreated. By controlling the shaker, high frequency vibrations can be recreated. On the shaker table, a small vacuum chamber is be mounted. Additionally thermal testing is also possible. Many vehicles experience simultaneous acceleration and vibration loads during their missions and are susceptible to nonlinear structural responses that can only be evaluated by combined environments testing. This approach to testing may allow payloads and vehicle subsystems to be tested in a more realistic setting prior to operations in the real world, and may lead to higher performance systems, as well as result in reduced cost. Such device altogether will be able to perform not only tests, but also to recreate conditions of a given rocket launch to enable investigation of failures.

  • Commitment Ladder in the Relationship between Service Providers and Customers as Added Value in Sustainable Services Development
    • Sławomir Ostrowski
    2021 Full text Sustainability

    The socioeconomic sphere and the relationships in which commitment occurs are important elements in the development of sustainable services. The study reported in this article identifies the elements that influence the development of the relationship between service providers and their customers and proposes a model that describes the state of the relationship between service providers and customers in terms of symmetrical commitment of both parties. Qualitative research including interviews with experts and case studies was completed, resulting in a ‘ladder of commitment’ model that identifies distinct commitment levels and specific commitment factors functioning at each of those levels. In practice, the proposed model makes it possible to assess the state of customer and provider commitment, identifying commitment deficits on the part of the customer or service provider. This article can provide practical added value for managers who are looking for ways to analyze customer commitment in order to develop sustainable services.

  • Common Independence in Graphs
    • Magdalena Lemańska
    • Magda Dettlaff
    • Jerzy Topp
    2021 Full text Symmetry-Basel

    Abstract: The cardinality of a largest independent set of G, denoted by α(G), is called the independence number of G. The independent domination number i(G) of a graph G is the cardinality of a smallest independent dominating set of G. We introduce the concept of the common independence number of a graph G, denoted by αc(G), as the greatest integer r such that every vertex of G belongs to some independent subset X of VG with |X| ≥ r. The common independence number αc(G) of G is the limit of symmetry in G with respect to the fact that each vertex of G belongs to an independent set of cardinality αc(G) in G, and there are vertices in G that do not belong to any larger independent set in G. For any graph G, the relations between above parameters are given by the chain of inequalities i(G) ≤ αc(G) ≤ α(G). In this paper, we characterize the trees T for which i(T) = αc(T), and the block graphs G for which αc(G) = α(G).

  • Compact 4 × 4 butler matrix with non‐standard phase differences for IoT applications
    • Adrian Bekasiewicz
    • Sławomir Kozieł
    2021 Full text ELECTRONICS LETTERS

    Butler matrices represent a popular class of feeding networks for antenna arrays. Large dimensions and the lack of flexibility in terms of achievable output phase difference make conventional Butler structures of limited use for modern communication devices. In this work, a compact planar 4 × 4 matrix with non-standard relative phase shifts of –30º, 150º, –120º, and 60º has been proposed. The structure is designed to operate at the centre frequency of 2.45 GHz. Small dimensions of 31.3 mm × 22.9 mm make it useful for Internet of Things applications. The structure operates from 2.35 GHz to 2.55 GHz which covers the industrial, scientific and medical (ISM) bandwidth. At the centre frequency, the measured amplitude and phase imbalance are 1.65 dB and ±4.3º, respectively. The proposed circuit has been compared to the state-of-the-art structures from the literature.

  • Company versus consumer performance: does brand community identification foster brand loyalty and the consumer’s personal brand?
    • Ilenia Confente
    • Wioleta Kucharska
    2021 Full text Journal of Brand Management

    This study investigates the effect of community identification in building brand loyalty (attitudinal and behavioural) and a personal brand via social networks. The proposed model explained the main community identification antecedents and how identification can lead to enhanced company and consumer performance. This study adopts the theoretical lens of uses and gratifications theory and identifies three motivational drivers of community identification: relationship-oriented motives, self-oriented motives and brand content-oriented motives. The data were analysed with a structural equation modelling method based on a convenience sample collected through a survey. This study extends the body of knowledge about the outcomes from an active social media usage, based on a UGT perspective. It relates community identification and its drivers to loyalty. Besides, it links community identification with personal branding, which is considered as a vital outcome expected by social media users. The findings suggested that self-oriented motives represented a key driver for taking part in an online community. In addition, community identification represents to be an important antecedent to build attitudinal loyalty rather than behavioural loyalty. Consequently, community identification was also found to be a significant driver for building a user’s personal brand.

  • Comparative 3D DEM simulations of sand–structure interfaces with similarly shaped clumps versus spheres with contact moments.
    • Aleksander Grabowski
    • Michał Nitka
    • Andrzej Tejchman-Konarzewski
    2021 Full text Acta Geotechnica

    Three-dimensional simulations of a monotonic quasi-static interface behaviour between initially dense cohesionless sand and a rigid wall of different roughness during tests in a parallelly guided direct shear test under constant normal stress are presented. Numerical modelling was carried out by the discrete element method (DEM) using clumps in the form of convex non-symmetric irregularly shaped grains. The clumps had an aspect ratio of 1.5. A regular grid of triangular grooves (asperities) along the wall with a different height at the same distance was assumed. The numerical results with clumps were directly compared under the same conditions with our earlier DEM simulations using pure spheres with contact moments with respect to the peak and residual interface friction angle, width of the interface shear zone, ratio between grain slips and grain rotations, distribution of contact forces and stresses. The difference between the behaviour of clumps and pure spheres with contact moments proved to be noticeable in the post-peak regime due to a different particle shape. The rolling resistance model with pure spheres was proved to be limited for capturing particle shape effects. Three different boundary conditions along the interface were proposed for micropolar continua, considering grain rotations and grain slips, wall grain moments and wall grain forces, and normalized interface roughness. The numerical results in this paper offer a better understanding of the interface behaviour of granular bodies in DEM and FEM simulations.

  • Comparative evaluation of different methods for determining phytochemicals and antioxidant activity in products containing betalains - Verification of beetroot samples
    • Barbara Kusznierewicz
    • Marika Konderak
    • Izabela Koss-Mikołajczyk
    • Jacek Namieśnik
    2021 Full text FOOD CHEMISTRY

    This study presents methods that can be used to assess the health quality of products containing betalains. The paper compares and verifies data on the phytochemical composition of three different pigmented beetroot cultivars using spectrophotometric, HPLC-DAD, HPTLC and LC-Q-Orbitrap-HRMS techniques. Additionally, we compared the total antioxidant activity in both the cell-free and cellular systems. Betalain contribution to antioxidant activity was also determined using post-column derivatization and it was found that in the case of red beetroot it is about 50%. Photometric measurements are recommended for a simple and inexpensive analysis of the total betacyanin and betaxanthin content. Liquid chromatography techniques produced more precise information on phytochemical composition in the tested samples. The combination of liquid chromatography with high-resolution mass spectrometry produced the largest amount of quantitative and qualitative data; in beetroot samples sixty-four phytochemicals have been identified therefore, this approach is recommended for more detailed metabolomics studies.

  • Comparative Study of the Mechanical Behaviour of Bitumen- and Cement-Dominated Mixtures with Reclaimed Asphalt
    • Miomir Miljković
    • Bohdan Dołżycki
    • Mariusz Jaczewski
    • Cezary Szydłowski
    2021 Full text

    The bitumen emulsion-based recycling is a commonly used maintenance treatment in the rehabilitation of low-and medium-volume roads in Europe. Nevertheless, the wide range of climatic conditions across the continent resulted in the variety of mixture concepts and the requirements being adopted for various local conditions. In this regard, the most commonly used parameter to distinguish between the main mixture concepts is bitumen to cement ratio. This article presents the comparison of the results of mechanical properties for different approachest to design of cold recycled mixtures with either bitumen or cement having the dominant role in the mechanical behaviour. In both cases, bitumen emulsion C60B5 and Portland cement CEM I were used as binding agents, and the considered cold recycled mixtures were designed to contain at least 70 % of reclaimed asphalt. The combinations of binding agents were selected based on the respective requirements. Mechanical properties were expressed by the indirect tensile strength, failure strain, and stiffness modulus, while the tests were conducted at the temperatures of 5 and 20 °C and the curing periods of 7 and 28 days. The comparison showed that the mixtures with the higher content of cement reached much higher stiffness and, from the aspect of the kinetics of mechanical properties development, they almost resembled cementitious materials. In contrast to this, the behaviour of bitumen-dominated mixtures, especially at earlier curing stages, was within the common requirements but also tended to have much higher strains at failure.

  • Comparative Study of the Reinforcement Type Effect on the Thermomechanical Properties and Burning of Epoxy-Based Composites
    • Kamila Salasinska
    • Mateusz Barczewski
    • Joanna Aniśko
    • Aleksander Hejna
    • Maciej Celiński
    2021 Full text Journal of Composites Science

    Aramid (AF), glass (GF), carbon (CF), basalt (BF), and flax (FF) fibers in the form of fabrics were used to produce the composites by hand-lay up method. The use of fabrics of similar grammage for composites’ manufacturing allowed for a comprehensive comparison of the properties of the final products. The most important task was to prepare a complex setup of mechanical and thermomechanical properties, supplemented by fire behavior analysis, and discuss both characteristics in their application range. The mechanical properties were investigated using tensile and flexural tests, as well as impact strength measurement. The investigation was improved by assessing thermomechanical properties under dynamic deformation conditions (dynamic mechanical–thermal analysis (DMTA)). All products were subjected to a fire test carried out using a cone calorimeter (CC).

  • Comparative study on total nitrogen prediction in wastewater treatment 1 plant and effect of various feature selection methods on machine learning algorithms performance
    • Faramarz Bagherzadeh
    • Mohammad Javad Mehrani
    • Milad Basirifard
    • Javad Roostaei
    2021 Full text Journal of Water Process Engineering

    Wastewater characteristics prediction in wastewater treatment plants (WWTPs) is valuable and can reduce the number of sampling, energy, and cost. Feature Selection (FS) methods are used in the pre-processing section for enhancing the model performance. This study aims to evaluate the effect of seven different FS methods (filter, wrapper, and embedded methods) on enhancing the prediction accuracy for total nitrogen (TN) in the WWTP influent flow. Four scenarios based on FS suggestions were defined and compared by three supervised Machine Learning (ML) algorithms, i.e. Artificial Neural Network (ANN), Random Forest (RF), and especially Gradient Boosting Machine (GBM). Input parameters, as daily time-series including pH, DO, COD, BOD, MLSS, MLVSS, NH4-N, and TN concentration, were used. Data set divided into train and unseen test data-sets, and performance precision of all models was carried out based on Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and correlation coefficient (R2). Results reveal that scenario IV which was suggested by Mutual Information, including NH4-N, COD, BOD, and DO had the best result rather than other FS methods. Furthermore, decision tree algorithms (RF and GBM) revealed better performance results in comparison to neural network algorithm (ANN). GBM generalized the dataset patterns very well and produced the best performance on unseen data-set, which shows the effectiveness of this state-of-the-art ML algorithm for wastewater components prediction.

  • Comparison of Absorbed and Intercepted Fractions of PAR for Individual Trees Based on Radiative Transfer Model Simulations
    • Wojciech Wojnowski
    • Shanshan Wei
    • Wenjuan Li
    • Tiangang Yin
    • Xian-Xiang Li
    • Genevieve Lai Fern Ow
    • Mohamed Lokman Mohd Yusof
    • Andrew J. Whittle
    2021 Full text Remote Sensing

    The fraction of absorbed photosynthetically active radiation (fAPAR) is a key parameter for estimating the gross primary production (GPP) of trees. For continuous, dense forest canopies, fAPAR, is often equated with the intercepted fraction, fIPAR. This assumption is not valid for individual trees in urban environments or parkland settings where the canopy is sparse and there are well-defined tree crown boundaries. Here, the distinction between fAPAR and fIPAR can be strongly influenced by the background and large illumination variations due to multi-scattering and shadows of buildings. This study investigates the radiative budget of PAR bands using a coupled leaf-canopy radiative transfer model (PROSPECT-DART), considering a suite of tropical tree species over a wide range of assumed leaf chlorophyll contents. The analyses simulate hyperspectral images (5 nm bandwidth) of individual tree crowns for the selected background (concrete vs. grass) and illumination conditions. We then use an artificial neural network-based method to partition sunlit vs. shaded leaves within each crown, as the latter have lower fAPAR and fIPAR values. Our results show fAPAR of sunlit leaves decreases with the ratio of diffuse to direct scene irradiance (SKYL), while SKYL has minimal influence for shaded leaves. Both fAPAR and fIPAR decrease at more oblique solar zenith angles (SZA). Higher values of fAPAR and fIPAR occur with concrete backgrounds and the influence of the background is larger at higher diffuse ratio and solar zenith angles. The results show that fIPAR is typically 6–9% higher than fAPAR, and up to 14% higher for sunlit leaves with a concrete background at SKYL = 0. The differences between the fIPAR and fAPAR also depend on the health condition of the leaves, such as chlorophyll content. This study can improve the understanding of urban individual trees fAPAR/fIPAR and facilitate the development of protocols for fAPAR field measurements.

  • Comparison of different one-parameter damage laws and local stress-strain approaches in multiaxial fatigue life assessment of notched components
    • Ricardo Branco
    • José Domingos Costa
    • L.p. Borrego
    • F. Berto
    • Seyed Mohammad Nazem Razavi
    • Wojciech Macek
    2021 Full text INTERNATIONAL JOURNAL OF FATIGUE

    This paper aims to compare the predictive capabilities of different one-parameter damage laws and local stress-strain approaches to assess the fatigue lifetime in notched components subjected to proportional bending-torsion loading. The tested fatigue damage parameters are defined using well-known stress-based, strain-based, SWT-based and energy-based relationships. Multiaxial cyclic plasticity at the notch-controlled process zone is accounted for within a 3D-FE linear-elastic framework using three local stress-strain approaches, namely Neuber’s rule, equivalent strain energy density rule (ESED) and the modified ESED rule. Regarding the local stress-strain approaches, irrespective of the fatigue damage parameter, Neuber’s rule always led to more conservative results, and the modified ESED rule resulted in slightly better fatigue life predictions when compared to the original ESED rule. As far as the fatigue damage parameters are concerned, energy-based models were more accurate, irrespective of the local stress-strain approach.

  • Comparison of nitrogen and VFA removal pathways in autotrophic and organotrophic anammox reactors
    • Xuejiao Yin
    • Md. Hasibur Rahaman
    • Wenbo Liu
    • Jacek Mąkinia
    • Jun Zhai
    2021 ENVIRONMENTAL RESEARCH

    Organotrophic anammox is a promising process for treating both nitrogen and organic containing wastewater than that of the traditional autotrophic anammox for sole nitrogen removal. However pathways of nitrogen removal particularly at metagenomic level in both processes are still unknown. Here we report, metabolic pathways of nitrogen removal in two lab-scale sequencing batch reactors (SBR), one autotrophic and another organotrophic (TOC/TN=0.1) anammox bacteria incubated over 220 days. Both reactors showed satisfactory nitrogen removal with 840.31mg N/L.d and 786.81mg N/L.d for autotrophic and organotrophic anammox reactors respectively. Four anammox species namely Candidatus B. fulgida, B. sinica, J. caeni and Candidatus K. stuttgartiensis were identified in both reactors. The Candidatus K. stuttgartiensis (4%) was dominant in autotrophic reactor whereas Candidatus J. caeni (10%) in the organotrophic reactor. The supply of organic promoted the growth of anammox bacteria more than three times higher than that of the autotrophic anammox reactor. The functional genes related to the DNRA pathway was obtained in all anammox species except for Candidatus K. stuttgartiensis. The co-existence of other DNRA (Armatimonadetes and Thauera) and partial denitrifying bacteria (Chloroflexi) was also found in both reactors. Moreover, functional genes related to acetate metabolism by acetyl-CoA way were obtained in all anammox bacteria except Candidatus B. fulgida which showed alternative ackA/Pac-t pathways in organic anammox reactor. Overall current results suggest that the anammox, DNRA and partial denitrification were the key nitrogen transformation pathways, particularly in organotrophic anammox reactor. Our findings will improve understanding of the practical application of organotrophic anammox for wider wastewater treatment.

  • Comparison of Renewable Energy Sources in ‘New’ EU Member States in the Context of National Energy Transformations
    • Agnieszka Wałachowska
    • Aranka Ignasiak-Szulc
    2021 Full text ENERGIES

    The European Union strives to create sustainable, low-carbon economies; therefore, energy policies of all member states should move towards renewable energy sources (RES). That concerns also the so-called new EU member states. These countries, on the one hand, are characterized by significant historical similarities in terms of post-communist legacy and adopted development strategies linked with the EU membership, and on the other hand, by significant social, economic and environmental differences resulting from different transformation and development paths and conditions. The question remains how the selected countries should cope with actions in the field of national energy transformations to confront the multiple challenges linked to assuring a significant level of sustainable development. In order to be successful, it is necessary to conduct an effective and rapid changes in the energy industry, which should be preceded by an analysis of the differentiation of countries in terms of their potentials. The results of such analyses should be helpful in selecting the most appropriate strategies for transformation of the described industry. Therefore, the purpose of the article is to assess the new EU member states for RES diversification and identify similar subgroups of countries using cluster analysis, taking into account the percentage share of individual renewable energy sources in total renewable energy production. This was done for the years 2010, 2015 and 2019 which should allow us to demonstrate the differences between them as a group and also reveal changes recorded over time for a single country. Ward’s method was used for the analysis. The presented approach to the analysis of energy production enabled the acquisition of new knowledge in this field and supported the assessment of the current state of RES. The results obtained can be used in countries of comparable specificity to undertake activities of similar nature in relation to internal energy production, technological development or common energy policy.

  • Comparison of safety levels required by adequate regulations for cargo ships of different types
    • Piotr Szulczewski
    2021 Full text Zeszyty Naukowe Akademii Morskiej w Szczecinie

    During the currently ongoing development of methods for assessing the safety of ships, it is imperative that a compromise between the accuracy of the results and the accessibility of obtaining results is reached. This paper shows the calculations of a theoretical hull against damage stability regulations as included in SOLAS 2020, ICLL 66/88 as amended in 2003 and MARPOL 78. The rules included in the currently valid regulations require certain righting arm curve properties from vessels before and after potential damage, which does not pose a high difficulty level to engineers. However, for many engineers and scientists working with these rules, it is unclear what kind of behavior (particularly roll motion) these righting arm curve parameters correspond. In this paper, a correlation between the required GZ properties and the actual roll motion of a ship in waves, as calculated with the well-established method proposed by the ITTC, is revealed, and a comparison of the results to the currently in use regulations as well as comparison between the methods themselves is made. The comparison reveals the impact of GZ curve parameters on the roll motion of the ship

  • Comparison of the Effectiveness of Health Systems in The European Countries-Two-Stage DEA Model
    • Justyna Kujawska
    2021 Full text

    This article compares the efficiency of health systems in selected European countries using two-stage data envelopment analysis (DEA), based on data from the EUROSTAT database. In the first step, DEA efficiency scores were calculated for health care systems and, subsequently, the external variables describing lifestyle were used to calculate the truncated regression. Health care resources (physicians, nurses, hospital beds, financial outlays, life expectancy in health) included in the health care system and the lifestyle factors of the population are: alcohol consumption, smoking, overweight. The root cause of health systems inefficiencies is health behaviours. The main practical significance of this study is that the conclusions drawn from the results can help policy makers to evaluate the performance of health systems as well as contribute to the identification of directions for improvement in the future.

  • Comparison of the fracture toughness of pine wood determined on the basis of orthogonal linear cutting and frame sawing
    • Daniel Chuchała
    • Kazimierz Orłowski
    • Gerhard Sinn
    • Aleksandra Konopka
    2021 Full text ACTA FACULTATIS XYLOLOGIAE ZVOLEN

    In this paper, the values of the fracture toughness of Scots pine determined by cutting tests are presented. The cutting tests were carried out using the samples of Scotch pine (Pinus sylvestris L.) from Pomeranian Region, Poland. These experiments were carried out on two research stands: orthogonal linear cutting tests were conducted using the microtome instrument and the frame saw PRW-15M was used for sawing tests. The values of the fracture toughness were determined following the recorded values of cutting power during the cutting tests (PRW-15M) and cutting forces (microtome instrument) with the use of models based on the elements of fracture mechanics. It was observed that the fracture toughness values determined following the orthogonal linear cutting tests were significantly lower, what could be caused by bending the wood fibers under the pressure of the cutting force.

  • Comparison of Traffic Flow Models with Real Traffic Data Based on a Quantitative Assessment
    • Aleksandra Romanowska
    • Kazimierz Jamroz
    2021 Full text Applied Sciences-Basel

    The fundamental relationship of traffic flow and bivariate relations between speed and flow, speed and density, and flow and density are of great importance in transportation engineering. Fundamental relationship models may be applied to assess and forecast traffic conditions at uninterrupted traffic flow facilities. The objective of the article was to analyze and compare existing models of the fundamental relationship. To that end, we proposed a universal and quantitative method for assessing models of the fundamental relationship based on real traffic data from a Polish expressway. The proposed methodology seeks to address the problem of finding the best deterministic model to describe the empirical relationship between fundamental traffic flow parameters: average speed, flow, and density based on simple and transparent criteria. Both single and multi-regime models were considered: a total of 17 models. For the given data, the results helped to identify the best performing models that meet the boundary conditions and ensure simplicity, empirical accuracy, and good estimation of traffic flow parameters.

  • Complementary green analytical procedure index (ComplexGAPI) and software
    • Justyna Płotka-Wasylka
    • Wojciech Wojnowski
    2021 Full text GREEN CHEMISTRY

    It is not easy to find appropriate tools for the evaluation of the “green”nature of analytical methodologies which involve the use of compounds, materials, or chemicals manufactured prior to the analytical step. Here, we propose a new metric for the evaluation of analytical procedures based on the GAC attributes. The proposed solution expands on the well-known green analytical procedure index by adding additional fields pertaining to the processes performed prior to the analytical procedure itself. Each field of the hexagon that was added to the GAPI pictogram corresponds to a different aspect of the described process and is coloured green if certain requirements are met. To showcase the utility of the proposed metric, it was used to evaluate analytical protocols for the determination of pesticides in urine samples. We believe that, following GAPI’s success, ComplexGAPI will also gain attention and eventually trust and acceptance from the chemical community. To facilitate the use of this tool, we have created freeware software for generating the ComplexGAPI pictograms.

  • Complexes of silanethiolate ligands: Synthesis, structure, properties and application
    • Agnieszka Pladzyk
    • Daria Kowalkowska-Zedler
    • Anna Ciborska
    • Andreas Schnepf
    • Anna Dołęga
    2021 Full text COORDINATION CHEMISTRY REVIEWS

    The purposeful syntheses of silanethiolate complexes started approximately in the mid-eighties of the 20th century but no summary of the synthetic efforts has been reported till now. The synthetic methods and the resulting complexes have some common features, which are emphasized throughout the review. Thereby specific difficulties during synthesis are outlined and the structures, properties and possible applications of the resulting complexes are presented. All groups of metals of the periodic table are included and associated with potential applications regarding the specific properties of the siliconsulfur bond and the attached metals.

  • Composite as a Material of the Future in the Era of Green Deal Implementation Strategies
    • Aleksander Czapla
    • Mahesh Ganesapillai
    • Jakub Drewnowski
    2021 Full text Processes

    Composite materials have become synonymous with modernity, desired in nearly every aspect of our daily lives, from simple everyday objects to sanitary facilities, pipelines, the construction of modern sewer networks, their renovation, water supply, and storage reservoirs, to complex structures—automotive, planes, and space science. Composites have seen a considerable rise in attention owing to their characteristics, durability, strength, reduced energy usage during the manufacturing process, and decreased transportation costs. Composite materials consistently outperform steel, cast iron, and concrete in terms of CO2 emissions. Additionally, these materials have a long service life of about 150 years or more and are corrosion-resistant. Today, continued sustainable development is contingent upon access to safe drinking water and the availability of its resources and modes of conveyance. As a result, composite pipes have considerable potential due to their very low flow rate, which directly affects the prices of drinking water pumping and irrigation systems. However, there are also certain disadvantages associated with fibre-reinforced composites, such as easy surface damage, low heat resistance (up to 220 °C), long product forming time, and high cost of the material. Additionally, the product’s initial high durability and extended life cycle, coupled with high abrasion resistance, anisotropic strength, and stiffness in the final phase, prove to be unfavourable since composite material cannot be rapidly reintroduced into the manufacturing cycle. However, its disposal requires a negligible amount of energy. The article discusses the various composite materials available, their applications, and the potential for further developing their manufacturing technology toward nanocomposites and composites of natural origin that are readily biodegradable at the end of their service life; dubbed “green composites”. The study’s findings are unequivocal: this class of composite materials warrants further investigation in the future since they align perfectly with the concept of sustainable economic growth and Green Deal implementation.

  • Composite Polyurethane-Polylactide (PUR/PLA) Flexible Filaments for 3D Fused Filament Fabrication (FFF) of Antibacterial Wound Dressings for Skin Regeneration
    • Paweł Szarlej
    • Iga Carayon
    • Przemysław Gnatowski
    • Marta Glinka
    • Martyna Mroczyńska
    • Anna Brillowska-Dąbrowska
    • Justyna Kucińska-Lipka
    2021 Full text Materials

    his paper addresses the potential application of flexible thermoplastic polyurethane (TPU) and poly(lactic acid) (PLA) compositions as a material for the production of antibacterial wound dressings using the Fused Filament Fabrication (FFF) 3D printing method. On the market, there are medical-grade polyurethane filaments available, but few of them have properties required for the fabrication of wound dressings, such as flexibility and antibacterial effects. Thus, research aimed at the production, characterization and modification of filaments based on different TPU/PLA compositions was conducted. The combination of mechanical (tensile, hardness), structural (FTIR), microscopic (optical and SEM), degradation (2 M HCl, 5 M NaOH, and 0.1 M CoCl2 in 20% H2O2) and printability analysis allowed us to select the most promising composition for further antibacterial modification (COMP-7,5PLA). The thermal stability of the chosen antibiotic—amikacin—was tested using processing temperature and HPLC. Two routes were used for the antibacterial modification of the selected filament—post-processing modification (AMI-1) and modification during processing (AMI-2). The antibacterial activity and amikacin release profiles were studied. The postprocessing modification method turned out to be superior and suitable for wound dressing fabrication due to its proven antimicrobial activity against E. coli, P. fluorescens, S. aureus and S. epidermidis bacteria.

  • Comprehensive Review of Fluorescence Applications in Gynecology
    • Joanna Polom
    • Leszek Kalinowski
    • Michele Diana
    • Manish Chand
    • Carmela Caballero
    • Sambor Sawicki
    • Karol Polom
    2021 Full text Journal of Clinical Medicine

    Since the introduction of indocyanine green (ICG) as a fluorophore in near-infrared imaging, fluorescence visualization has become an essential tool in many fields of surgery. In the field of gynecology, recent new applications have been proposed and found their place in clinical practice. Different applications in gynecology were investigated, subcategorized, and overviewed concerning surgical applications and available dyes. Specific applications in which fluorescence-guided surgery was implemented in gynecology are described in this manuscript—namely, sentinel node biopsy, mesometrium visualization, angiography of different organs, safety issues in pregnant women, ureters visualization, detection of peritoneal metastases, targeted fluorophores for cancer detection, fluorescent contamination hysterectomy, lymphography for lower limb lymphedema prevention, tumor margin detection, endometriosis, and metastases mapping. With evolving technology, further innovative research on the new applications of fluorescence visualization in cancer surgery may help to establish these techniques as standards of high-quality surgery in gynecology. However, more investigations are necessary in order to assess if these innovative tools can also be effective to improve patient outcomes and quality of life in different gynecologic malignancies.

  • Comprehensive thermodynamic analysis of steam storage in a steam cycle in a different regime of work: A zero-dimensional and three-dimensional approach
    • Paweł Ziółkowski
    • Natalia Szewczuk-Krypa
    • Anna Butterweck
    • Michał Stjanke
    • Stanisław Głuch
    • Marta Drosińska-Komor
    • Anna Milewska
    • Jerzy Głuch
    2021 Full text JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME

    Due to the current trends aiming to reduce carbon dioxide emissions by increasing the use of renewable energy sources, changes are required in the operation of coal-fired steam units. The unstable nature of renewable energy sources, depending on weather conditions, means that the amount of energy produced varies and is not always in line with peak demand. To ensure the security and stability of energy supplies in the energy system, renewable sources should cooperate with units independent of environmental conditions. With conventional steam systems, the main issue of such energy storage applied to steam turbine units presented in the paper, which, in the event of a need for a sudden reduction of the system load, prevents overloading of the boiler and turbines, improving the safety of the system. This article presents a thermodynamic model of this energy storage. A zero-dimensional (0D) model was implemented, including the operating parameters of the unit. This model directly relates to the thermodynamic parameters defined at specific points of the thermodynamic cycle. Based on the 0D model, it was shown that the process of loading the energy storage with steam leads to a load reduction of up to 4%. On the other hand, when discharging the stored energy, the net power of the steam block may increase by 0.4%. For more detailed analysis, a three-dimensional (3D) non-equilibrium with including cross effects approach was applied. This approach is based on flow models, with phase transitions that determine temperature fields, densities, phase transition in relevant space, and is used for more accurate analysis. Here we investigate the relationship between the 0D and 3D approaches in the context of steam storage. The combination of these two approaches is the fundamental novelty of the article.

  • Comprehensive thermodynamic analysis of the CAES system coupled with the underground thermal energy storage taking into account global, central and local level of energy conversion
    • Rafał Hyrzyński
    • Paweł Ziółkowski
    • Sylwia Gotzman
    • Bartosz Kraszewski
    • Tomasz Ochrymiuk
    • Janusz Badur
    2021 RENEWABLE ENERGY

    A key aspect of CAES is the optimal configuration of the thermodynamic cycle. In this paper, the situation of cooperation between the current conventional power plants and wind farms is analyzed, and then, based on thermodynamic models, the process of storing thermal and electrical energy in the CAES system coupled with a heat storage and recovery is developed. Therefore, three levels can be distinguished, namely: the global level of energy production; the central level of energy conversion and storage; and the local level of heat storage. Two different types of a CAES, with and without an Underground Heat Exchanger (UHE), were analyzed. The round-trip efficiency of CAES with a UHE approaches 52.26%. The article also analyses transient phenomena of charging and discharge the heat storage with UHE. The heat transfer rate and temperature received from the underground thermal energy storage was estimated. For this purpose, preliminary thermal-FSI approach was coupled with zerodimensional model of CAES. The newly proposed CAES with a UHE, never studied before, can be used for applications requiring a high round-trip efficiency.

  • Computational analysis of an infinite magneto-thermoelastic solid periodically dispersed with varying heat flow based on non-local Moore–Gibson–Thompson approach
    • Ahmed E. Abouelregal
    • Hamid M. Sedighi
    • Ali H. Shirazi
    • Mohammad Malikan
    • Victor Eremeev
    2021 Full text CONTINUUM MECHANICS AND THERMODYNAMICS

    In this investigation, a computational analysis is conducted to study a magneto-thermoelastic problem for an isotropic perfectly conducting half-space medium. The medium is subjected to a periodic heat flow in the presence of a continuous longitude magnetic field. Based on Moore–Gibson–Thompson equation, a new generalized model has been investigated to address the considered problem. The introduced model can be formulated by combining the Green–Naghdi Type III and Lord–Shulman models. Eringen’s non-local theory has also been applied to demonstrate the effect of thermoelastic materials which depends on small scale. Some special cases as well as previous thermoelasticity models are deduced from the presented approach. In the domain of the Laplace transform, the system of equations is expressed and the problem is solved using state space method. The converted physical expressions are numerically reversed by Zakian’s computational algorithm. The analysis indicates the significant influence on field variables of non-local modulus and magnetic field with larger values. Moreover, with the established literature, the numerical results are satisfactorily examined.

  • Computational and experimental evaluation of view out according to European Standard EN17037.
    • Marta Waczyńska
    • Natalia Sokół
    • Justyna Martyniuk-Pęczek
    2021 BUILDING AND ENVIRONMENT

    This paper presents an experimental evaluation of view out based on EN17037:2018 Daylight in Buildings within an educational building. The primary motivation to conduct the research was an introduction of a view out appraisal criteria by the mentioned standard. The study gives insights into the following: (i) the use of computational evaluation of an outside view according to the EN17037 criteria (ii) the use of the direct simultaneous questionnaire to assess the view out (iii) a description of the relationships between the normative criteria and users' subjective assessments of view out, and (iv) the link between the quantitative and qualitative parameters of the evaluation of view out. The study was conducted using a three step approach: S1 – a computational evaluation of the outside view according to the standard's recommendations: distance to the nearest obstacle, number of visible layers and angle of the view; S2 – a view out evaluation based on a direct questionnaire in the selected indoor spaces under various daylight conditions; S3 – analysis and comparison of the results. The data was collected in 2019 and 2020 with 169 evaluations from volunteering architecture students. The key findings are: (i) the outcome of the subjective participants' evaluation of the view out differs from the results generated through computational simulations based on the EN17037 ratings (ii) similar results were recorded in reference to the estimation of the layers of the view, and (iii) the responders rated the view out one rank lower than the computational evaluation suggests.

  • Computational fluid dynamics simulation of heat transfer from densely packed gold nanoparticles to isotropic media
    • Piotr Radomski
    • Paweł Ziółkowski
    • Dariusz Mikielewicz
    • Luciano de Sio
    2021 Full text Archives of Thermodynamics

    This work aims to determine and compare heat generation and propagation of densely packed gold nanoparticles (Au NPs) induced by a resonant laser beam (532 nm) according to the Mie theory. The heat flux propagation is transferred into the materials, which here are: silica glass; soda-lime-silica glass; borosilicate glass; polymethyl methacrylate (PMMA); polycarbonate (PC); and polydimetylosiloxane (PDMS). This analysis aims to select the optimum material serving as a base for using photo-thermoablation. On the other hand, research focused only on Newtonian heat transfer in gold, not on non-Fourier ones, like the Cattaneo approach. As a simulation tool, a computational fluid dynamics code with the second-order upwind algorithm is selected. Results reveal a near-Gaussian and Gaussian temperature distribution profile during the heating and cooling processes, respectively. Dependence between the maximum temperature after irradiation and the glass thermal conductivity is observed confirming the Fourier law. Due to the maximum heating area, the borosilicate or soda-lime glass, which serves as a base, shall represent an excellent candidate for future experiments.

  • Computational Methods for Liver Vessel Segmentation in Medical Imaging: A Review
    • Marcin Ciecholewski
    • Michał Kassjański
    2021 Full text SENSORS

    The segmentation of liver blood vessels is of major importance as it is essential for formulating diagnoses, planning and delivering treatments, as well as evaluating the results of clinical procedures. Different imaging techniques are available for application in clinical practice, so the segmentation methods should take into account the characteristics of the imaging technique. Based on the literature, this review paper presents the most advanced and effective methods of liver vessel segmentation, as well as their performance according to the metrics used. This paper includes results available for four imaging methods, namely: computed tomography (CT), computed tomography angiography (CTA), magnetic resonance (MR), and ultrasonography (USG). The publicly available datasets used in research are also presented. This paper may help researchers gain better insight into the available materials and methods, making it easier to develop new, more effective solutions, as well as to improve existing approaches. This article analyzes in detail various segmentation methods, which can be divided into three groups: active contours, tracking-based, and machine learning techniques. For each group of methods, their theoretical and practical characteristics are discussed, and the pros and cons are highlighted. The most advanced and promising approaches are also suggested. However, we conclude that liver vasculature segmentation is still an open problem, because of the various deficiencies and constraints researchers need to address and try to eliminate from the solutions used.

  • Computer Support of Analysis of Optical Spectra Measurements
    • Sandra Pawłowska
    2021 Full text Engineering Proceedings

    The verification of measurement errors has a big impact on the assessment of the accuracy of conducted measurements and obtained results. In many cases, computer simulation results are compared with measurement results in order to evaluate measurement errors. The purpose of our research was to check the accuracy of measurements made with a Fabry–Perot interferometer working in the transmission mode. In the measurement setup, a 1310 nm superluminescent diode light source, single-mode optical fibers and an optical spectrum analyzer were used. The influence of the length of the resonating cavity and refractive index on the envelope of the optical spectrum was investigated. A program was created that models the envelope of the optical spectrum on the basis of the length of the resonating cavity, the refractive index and the light source output spectral characteristic, which in simulation was assumed to have the shape of Gaussian distribution. After the simulation the program compares the simulated and measured optical spectrum. The comparison of simulated and measured optical spectra proved to be challenging due to the shift in the position of the central peak between the simulated and measured optical spectrum. There are two ways to perform model fitting: by adjusting the position of central peaks or minimums next to the central peak. It was observed that the second solution was more optimal and was implemented in the program.

  • Computer support of analysis optical spectra measurements
    • Sandra Pawłowska
    • Jakub Gierowski
    2021 Full text

    Verification of measurement errors has a big impact on assessment of accuracy of conducted measurements and obtained results. In many cases computer simulation results are compared with measurement results in order to evaluate measurement errors. The purpose of our research was to check the accuracy of measurements made with Fabry-Perot interferometer working in the transmission mode. In measurement setup, a 1310 nm superluminescent diode light source, single-mode optical fibres and optical spectrum analyser were used. Influence of length of resonating cavity and refractive index on the envelope of interferogram was investigated. We created a program that models envelope of the interferogram on the basis of: length of the resonating cavity, refractive index and light source output spectral characteristic, which in simulation, was assumed to have shape of Gaussian distribution. After the simulation the program compares simulated and measured interferograms. The comparison of simulated and measured interferograms proved to be challenging due to the shift in the position of the central peak between the simulated and measured interferogram. There are two ways to perform model fitting: by adjusting the position of central peaks or minimums next to the central peak. It was observed, that the second solution was more optimal and was implemented in the program

  • Concept of an Innovative Autonomous Unmanned System for Bathymetric Monitoring of Shallow Waterbodies (INNOBAT System)
    • Mariusz Specht
    • Andrzej Stateczny
    • Cezary Specht
    • Szymon Widźgowski
    • Oktawia Lewicka
    • Marta Wiśniewska
    2021 Full text ENERGIES

    Bathymetry is a subset of hydrography, aimed at measuring the depth of waterbodies and waterways. Measurements are taken inter alia to detect natural obstacles or other navigational obstacles that endanger the safety of navigation, to examine the navigability conditions, anchorages, waterways and other commercial waterbodies, and to determine the parameters of the safe depth of waterbodies in the vicinity of ports, etc. Therefore, it is necessary to produce precise and reliable seabed maps, so that any hazards that may occur, particularly in shallow waterbodies, can be prevented, including the high dynamics of hydromorphological changes. This publication is aimed at developing a concept of an innovative autonomous unmanned system for bathymetric monitoring of shallow waterbodies. A bathymetric and topographic system will use autonomous unmanned aerial and surface vehicles to study the seabed relief in the littoral zone (even at depths of less than 1 m), in line with the requirements set out for the most stringent International Hydrographic Organization (IHO) order—exclusive. Unlike other existing solutions, the INNOBAT system will enable the coverage of the entire surveyed area with measurements, which will allow a comprehensive assessment of the hydrographic and navigation situation in the waterbody to be conducted.

  • Concept of managing quality in baking industry, in vector representation
    • Radosław Drozd
    2021 Full text Organizacja i Zarządzanie : kwartalnik naukowy

    The author introduced an innovative metrisable method of describing a manufacturing process. The idea of vector structure of a manufacturing process allows to formulate quantitative relations between the activity of input streams, elements of product quality, and measurable effects of losses. The structure was basis for the formulation of the concept of the process of managing product quality in the baking industry in a vector representation. The application of systems engineering allows for a measurable answer to the fundamental questions of the goal of the manufacturing process, its efficiency in the context of combining all the elements, including product quality, as well as other improving activities.

  • Concurrent Video Denoising and Deblurring for Dynamic Scenes
    • Efkleidis Katsaros
    • Piotr Kopa Ostrowski
    • Daniel Węsierski
    • Anna Jezierska
    2021 Full text IEEE Access

    Dynamic scene video deblurring is a challenging task due to the spatially variant blur inflicted by independently moving objects and camera shakes. Recent deep learning works bypass the ill-posedness of explicitly deriving the blur kernel by learning pixel-to-pixel mappings, which is commonly enhanced by larger region awareness. This is a difficult yet simplified scenario because noise is neglected when it is omnipresent in a wide spectrum of video processing applications. Despite its relevance, the problem of concurrent noise and dynamic blur has not yet been addressed in the deep learning literature. To this end, we analyze existing state-of-the-art deblurring methods and encounter their limitations in handling non-uniform blur under strong noise conditions. Thereafter, we propose a first-to-date work that addresses blur- and noise-free frame recovery by casting the restoration problem into a multi-task learning framework. Our contribution is threefold: a) We propose R2-D4, a multi-scale encoder architecture attached to two cascaded decoders performing the restoration task in two steps. b) We design multi-scale residual dense modules, bolstered by our modulated efficient channel attention, to enhance the encoder representations via augmenting deformable convolutions to capture longer-range and object-specific context that assists blur kernel estimation under strong noise. c) We perform extensive experiments and evaluate state-of-the-art approaches on a publicly available dataset under different noise levels. The proposed method performs favorably under all noise levels while retaining a reasonably low computational and memory footprint.