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Gdańsk University of Technology

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Publications from the year 2020

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  • Multi-transformer primary-side regulated flyback converter for supplying isolated IGBT and MOSFET drivers
    • Maciej Kolincio
    • Piotr Chrzan
    • Piotr Musznicki
    2020 Full text IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    This paper presents primary-side voltage regulated multi-transformer quasi-resonant flyback converter (MTFC) for supplying isolated power switch drivers. The proposed topology offers distinct advantages over frequently used flyback converter possessing one high frequency transformer with isolated multiple outputs. Particularly, when a large number of separate dc supply units is required, then MTFC enables improved regular distribution of magnetic coupling between the common primary and the multiple secondary transformers' windings providing high degree of galvanic and electromagnetic isolation between multiple outputs. Primary side voltage regulation is based on the average value of output voltages estimation using auxilliary RDC circuit mounted across the primary windings. Operation principles of MTFC are enhanced with analytical study of cross regulation of multiple output voltages at unbalanced load conditions, indicating reduced voltage deviation of multiple outputs by applying the primary-side average voltage regulation. Experimental results of prototype 2, 3, and 6-transformer quasi-resonant flyback converters confirmed their cross regulation quality and application potential for independent multiple output supplies.

  • Musical Instrument Tagging Using Data Augmentation and Effective Noisy Data Processing
    • Damian Koszewski
    • Bożena Kostek
    2020 Full text JOURNAL OF THE AUDIO ENGINEERING SOCIETY

    Developing signal processing methods to extract information automatically has potential in several applications, for example searching for multimedia based on its audio content, making context-aware mobile applications (e.g., tuning apps), or pre-processing for an automatic mixing system. However, the last-mentioned application needs a significant amount of research to reliably recognize real musical instruments in recordings. In this paper we primarily focus on how to obtain data for efficiently training, validating, and testing a deep-learning model by using a data augmentation technique. These data are transformed into 2D feature spaces, i.e., mel-scale spectrograms. The Neural Network used in the experiments consists of a single-block DenseNet architecture and a multi-head softmax classifier for efficient learning with the mixup augmentation. For automatic noisy data labeling, the batch-wise loss masking, which is robust to corrupting outliers in data, was applied. To train the models, various audio sample rates and different audio representations were utilized. The method provides promising recognition scores even with real-world recordings that contain noisy data.

  • Mutual Interaction between Temperature and DO Set Point on AOB and NOB Activity during Shortcut Nitrification in a Sequencing Batch Reactor in Terms of Energy Consumption Optimization
    • Mehdi Sharifshourjeh
    • Przemysław Kowal
    • Jakub Drewnowski
    • Bartosz Szeląg
    • Aleksandra Szaja
    • Grzegorz Łagód
    2020 Full text ENERGIES

    Recently, many wastewater treatment plants (WWTPs) have had to deal with serious problems related to the restrictive requirements regarding the euent quality, as well as significant energy consumption associated with it. In this situation, mainstream deammonification and/or shortened nitrification-denitrification via nitrite (so-called “nitrite shunt”) is a new promising strategy. This study shows the mechanisms and operating conditions (e.g., dissolved oxygen (DO) concentration, temp.), leading to the complete domination of ammonium oxidizing bacteria (AOB) over nitrite oxidizing bacteria (NOB) under aerobic conditions. Its successful application as shortcut nitrification in the sequencing batch reactor (SBR) technology will represent a paradigm shift for the wastewater industry, oering the opportunity for ecient wastewater treatment, energy-neutral or even energy-positive facilities, and substantial reductions in treatment costs. In this study, under low and moderate temperatures (10–16 C), averaged DO concentrations (0.7 mg O2/L) were preferable to ensure beneficial AOB activity over NOB, by maintaining reasonable energy consumption. Elevated temperatures (~30 C), as well as increased DO concentration, were recognized as beneficial for the NOB activity stimulation, thus under such conditions, the DO limitation seems to be a more prospective approach.

  • Nadmierne osiadania nawierzchni drogowej w ujęciu geotechnicznym - przyczyny, monitoring, możliwe metody naprawy
    • Grzegorz Horodecki
    2020

    Nadmierne osiadania nawierzchni stanowią „wieczny” problem użytkowników dróg. Z odkształceniami nawierzchni łączy się obniżenie komfortu i bezpieczeństwa jazdy (BRD). Jedną z podstawowych przyczyn takiego zjawiska jest zachowanie się podłoża gruntowego. Najczęściej dotyczy to zjawiska osiadania podłoża gruntowego, stanowiącego efekt ściśliwości gruntów w wyniku przyłożenia obciążenia i jest przekroczeniem stanów granicznych użytkowalności (SGU). W rzadszych przypadkach odkształcenia wiążą się z przekroczeniem stanu granicznego nośności (SGN).

  • NADPH Oxidase Gene Polymorphism is Associated with Mortality and Cardiovascular Events in 7-Year Follow-Up
    • Milena Racis
    • Wojciech Sobiczewski
    • Anna Stanisławska-Sachadyn
    • Marcin Wirtwein
    • Elżbieta Bluj
    • Michał Nedoszytko
    • Joanna Borzyszkowska
    • Janusz Limon
    • Andrzej Rynkiewicz
    • Marcin Gruchała
    2020 Full text Journal of Clinical Medicine

    The CYBA gene encodes the regulatory subunit of NADPH oxidase, which maintains the redox state within cells and in the blood vessels. That led us to investigate the course of coronary artery disease (CAD) with regards to CYBA polymorphisms. Thus, we recruited 1197 subjects with coronary atherosclerosis and observed them during 7-year follow-up. Three CYBA polymorphisms: c.214C>T (rs4673), c.-932G>A (rs9932581), and c.*24G>A (1049255) were studied for an association with death, major adverse cardiovascular events (MACE) and an elective percutaneous coronary intervention or coronary artery bypass grafting (PCI/CABG). We found an association between the CYBA c.214C>T polymorphism and two end points: death and PCI/CABG. CYBA c.214TT genotype was associated with a lower risk of death than C allele (9.5% vs. 21%, p < 0.05) and a higher risk of PCI/CABG than C allele (69.3% vs. 51.7%, p < 0.01). This suggests that the CYBA c.214TT genotype may be a protective factor against death OR = 0.47 (95%CI 0.28–0.82; p < 0.01), while also being a risk factor for an elective PCI/CABG OR = 2.36 (95%CI 1.15–4.82; p < 0.05). Thus, we hypothesize that among patients with coronary atherosclerosis, the CYBA c.214TT genotype contributes to atherosclerotic plaque stability by altering the course of CAD towards chronic coronary syndrome, thereby lowering the incidence of fatal CAD-related events.

  • Nagrzewanie się elementów układu obróbkowego w docieraniu powierzchni płaskich
    • Adam Barylski
    2020

    Przedstawiono analizę temperatury elementów układu wykonawczego docierarki jednotarczowej przy użyciu kamery termowizyjnej. W badaniach stosowano różne wartości prędkości obrotowej tarczy docierającej oraz dwa zakresy ziarnistości mikroziaren ściernych w dozowanej paście. Obrabiano elementy płaskie wykonane ze stali chromowo - niklowej oraz brązu berylowego.

  • Nano Tin/Tin Oxide Attached onto Graphene Oxide Skeleton as a Fluorine Free Anode Material for Lithium-Ion Batteries
    • Andrzej Nowak
    • Konrad Trzciński
    • Mariusz Szkoda
    • Grzegorz Trykowski
    • Maria Gazda
    • Jakub Karczewski
    • Marcin Łapiński
    • Dominik Maskowicz
    • Mirosław Sawczak
    • Anna Lisowska-Oleksiak
    2020 INORGANIC CHEMISTRY

    Herein, we show a composite formation method of tin/tin oxide nanoparticles with graphene oxide and CMC based on laser ablation technique as an electrode material for energy storage devices. The material exhibited a three-dimensional conducting graphene oxide network decorated with tin or tin oxide nanoparticles. The structure, homogeneous distribution of nanoparticles, and direct contact between inorganic and organic parts were confirmed by scanning electron microscopy and high-resolution transmission electron spectroscopy. Electrochemical performances of composite electrode material showed a reversible capacity of 644 mAh/g at a current density equal to 35 mA/g, and 424 mAh/g at 140 mA/g. The capacity retention of 90% after 250 cycles show that tested electrode material is suitable as a negative electrode for lithium-ion batteries.

  • Nanocrystalline diamond sheets as protective coatings for fiber-optic measurement head
    • Monika Kosowska
    • Daria Majchrowicz
    • Mateusz Ficek
    • Paweł Wierzba
    • Yafit Fleger
    • Dror Fixler
    • Małgorzata Szczerska
    2020 CARBON

    Fiber-optic sensors find numerous applications in science and industry, but their full potential is limited because of the risk of damaging the measurement head, in particular, due to the vulnerability of unprotected tips of the fiber to mechanical damage and aggressive chemical agents. In this paper, we report the first use of a new nanocrystalline diamond structure in a fiber-optic measurement head as a protective coating of the fiber tip. The nanocrystalline sheet structures, produced with the use of Microwave Plasma Assisted Chemical Vapor Deposition System (MW PA CVD), were characterized by Scanning Electron Microscopy (SEM) and successfully transferred from the deposition substrate onto the surface of the tip of a single-mode fiber sensor head. A Fabry-Perot sensing interferometer for distance measurement comprising that fiber was built. The measurement results were compared with numerical modeling. High values of achieved correlation coefficients (R2 > 0.99) between a linear model and distance measurements data indicate that the diamond sheet does not affect the correct operation of the sensor while extending its potential scope of applications.

  • Nanodiamond phantoms mimicking human liver: perspective to calibration of T1 relaxation time in magnetic resonance imaging
    • Anna Sękowska
    • Daria Majchrowicz
    • Agnieszka Sabisz
    • Mateusz Ficek
    • Barbara Bułło-Piontecka
    • Monika Kosowska
    • Lina Jing
    • Robert Bogdanowicz
    • Małgorzata Szczerska
    2020 Full text Scientific Reports

    Phantoms of biological tissues are materials that mimic the properties of real tissues. This study shows the development of phantoms with nanodiamond particles for calibration of T1 relaxation time in magnetic resonance imaging. Magnetic resonance imaging (MRI) is a commonly used and non-invasive method of detecting pathological changes inside the human body. Nevertheless, before a new MRI device is approved for use, it is necessary to calibrate it properly and to check its technical parameters. In this article, we present phantoms of tissue with diamond nanoparticles dedicated to magnetic resonance calibration. The method of producing phantoms has been described. As a result of our research, we obtained phantoms that were characterized by the relaxation time T1 the same as the relaxation time of the human tissue T1 = 810.5 ms. Furthermore, the use of diamond nanoparticles in phantoms allowed us to tune the T1 value of the phantoms which open the way to elaborated phantoms of other tissues in the future.

  • Nanofiltration in the food industry
    • Roberto Castro-Muñoz
    • Emilia Gontarek
    2020

    Nanofiltration (NF), as a pressure-driven membrane process, has been widely demonstrated to have great potential for food processing applications. There are several advantages of this membrane process over traditional methods that makes NF suitable for food processing, such as the low thermal damage to the product, higher aroma retention, lower energy consumption, and low maintenance costs. In this chapter, according to the recent literature, a review of the main areas of NF applications in the food industry is presented, such as juice and plant extract clarification and concentration, wine application, sugar industry, dairy processing, and recovery of high-added value compounds from food wastes. The productivity and the separation performance of NF membranes toward target compounds have also been discussed.

  • Nanoindentation tests titanium alloy Ti-6Al-4V after interference laser treatment
    • Magdalena Jażdżewska
    • Dominika Trochowska
    • Michał Bartmański
    2020 Full text Inżynieria Materiałowa

    The study aimed was to assess selected mechanical properties of surface layers obtained after interference laser treatment – DLIL of titanium alloy Ti-6Al-4V used for implants. The samples were melted in still air at room temperature, for this purpose Nd:YAG laser was used, the number of laser shots was variable. Next, nanoindentation tests were performed, based on which Young’s modulus and nanohardness in the obtained surface layers were determined. An increase in nanohardness is observed in the surface layers after laser melting. An increase in the modulus of elasticity and higher hardness was observed for both the first and second areas on the sample surface. In the case of a sample for which three laser beam shots were used, hardness and Young’s modulus almost doubled. On the basis of the obtained results, it was found that the modified Ti-6Al-4V alloy can be used as an implant material, and the proposed method of modifying its surface may extend the life of such implants and improve their frictional properties.

  • Nanoparticles: Synthesis, characteristics, and applications in analytical and other sciences
    • Muhammad Sajid
    • Justyna Płotka-Wasylka
    2020 Full text MICROCHEMICAL JOURNAL

    Nanoparticles (NPs) are widely employed in different research areas, ranging from analytical chemistry and environmental science to medicine, the agriculture and pharmaceutical industry. This is mainly due to the unique characteristics of NPs and the novelty they introduce in such applications. In analytical chemistry, the role of NPs can differ depending on the nature of the steps involved in analytical process. NPs are probably most useful for detection, but sample preparation has also profited from them. For instance, NPs can advantageously replace conventional sorbents for solid-phase extraction. Moreover, NPs are being increasingly used as stationary phases in gas and liquid chromatography or electrochromatography. In this review, a brief summary on the classification, synthesis methods, and properties of NPs is given. Moreover, the examples of applications in different research area are shortly presented. However, the merits of this work are to present the use of NPs in analytical chemistry field.

  • Narracje o świeżej traumie. Upamiętnianie ataków terrorystycznych w krajobrazie codziennym miast
    • Anna Awtuch
    • Agnieszka Gębczyńska-Janowicz
    2020 Full text Politeja. Pismo Wydziału Studiów Międzynarodowych i Politycznych Uniwersytetu Jagiellońskiego

    Recent trauma Narratives: commemorating terrorist attacks in Everyday cityscape Contemporary city incidentally becomes a non-accidental target of acts violating the primary sense of security and safety. The fundamental assumptions about so- cial and interpersonal interactions that guarantee social life are severely disturbed. These events, primarily the ones related to terrorist attacks, leave in social memo- ry traces associated with everyday places scattered in urban landscape. Should the trace of a catastrophe be preserved and exhibited, or should it be interpreted to give a new meaning to endangered places? What significance can one attribute to trauma narratives in everyday landscape?To what extent can spatial and ephemeral narratives related to dramatic events address the social need of coping with trauma and constructing a new approach to a given place? Spontaneous and official commemorative forms are created in response to terrorist attacks in Europe and the U.S.A. Official memorials are created over just a few years and sometimes even one year, which corresponds to a natural closure of mourning process leading to the acceptance of loss and reconstructing life. However, other representations – spontaneous memorials created in the aftermath of attacks, composed of objects left in urban space to honour victims and survivors – become an important element of collective mourning ritual and constitute a transition from informal commemoration to top-down representations. The article discusses how different forms of trauma narratives constructed in urban space can enhance trauma recovery.

  • Natural carbon-based quantum dots and their applications in drug delivery: A review
    • Akhila Nair
    • Józef Haponiuk
    • Sabu Thomas
    • Sreeraj Gopi
    2020 Full text BIOMEDICINE & PHARMACOTHERAPY

    Natural carbon based quantum dots (NCDs) are an emerging class of nanomaterials in the carbon family. NCDs have gained immense acclamation among researchers because of their abundance, eco-friendly nature, aqueous solubility, the diverse functionality and biocompatibility when compared to other conventional carbon quantum dots (CDs).The presence of different functional groups on the surface of NCDs such as thiol, carboxyl, hydroxyl, etc., provides improved quantum yield, physicochemical and optical properties which promote bioimaging, sensing, and drug delivery. This review provides comprehensive knowledge about NCDs for drug delivery applications by outlining the source and rationale behind NCDs, different routes of synthesis of NCDs and the merits of adopting each method. Detailed information regarding the mechanism behind the optical properties, toxicological profile including biosafety and biodistribution of NCDs that are favourable for drug delivery are discussed. The drug delivery applications of NCDs particularly as sensing and real-time tracing probe, antimicrobial, anticancer, neurodegenerative agents are reviewed. The clinical aspects of NCDs are also reviewed as an initiative to strengthen the case of NCDs as potent drug delivery agents.

  • Nauka w świecie cyfrowym okiem młodego inżyniera - metody i aplikacje wspomagające uczenie
    • Konrad Witek
    • Damian Białobrzycki
    • Tomasz Skiba
    • Przemysław Falkowski-Gilski
    2020 Pismo PG

    W niniejszym artykule opisano metody uczenia się oraz popularne aplikacje wspomagające przyswajanie wiedzy. Jest to kontynuacja poprzedniej części, poświęconej procesowi uczenia oraz najpopularniejszym technikom. Zawarte informacje można traktować jako wskazówki dla osób w trakcie tzw. instytucjonalnej nauki - szkoła, studia, kursy doszkalające - związanej z ciągłą potrzebą samodoskonalenia i podnoszenia kwalifikacji.

  • Nauka w świecie cyfrowym okiem młodego inżyniera – proces i techniki uczenia
    • Konrad Witek
    • Damian Białobrzycki
    • Tomasz Skiba
    • Przemysław Falkowski-Gilski
    2020 Pismo PG

    W obecnym świecie, z uwagi na wszechobecność cyfrowych urządzeń, odtwarzaczy multimedialnych itp., trudno jest skupić uwagę na pojedynczej czynności. Z kolei wzrost dostępnych źródeł informacji powoduje niekiedy rozproszenie i problemy z koncentracją. Naturalne wydaje się skorzystanie z urządzenia osobistego, które posiada niemal każdy z nas, czyli smartfona, w celu poprawy koncentracji i systematycznej pracy. W niniejszym artykule opisano proces uczenia się oraz techniki przyswajania wiedzy. Zawarte informacje traktować można jako wskazówki dla osób w trakcie tzw. instytucjonalnej nauki - szkoła, studia, kursy doszkalające- związanej z ciągłą potrzebą samodoskonalenia i podnoszenia kwalifikacji.

  • Naukowcy pracują nad poprawą efektywności terapii borowo-neutronowej w chorobach nowotworowych
    • Brygida Mielewska
    • Marek Maryański
    • Edyta Michaś
    2020 Pismo PG

    Badacze konsorcjum zamierzają wspólnie wypracować nowatorską metodologię, która znacznie poprawi kliniczną efektywność terapii boro- wo-neutronowej chorób nowotworowych. Technologia wypracowana przez konsorcjum stanie się podstawą nowych produktów i usług dla klinik onkologicznych w skali globalnej.

  • Near Field Coupled Wireless Microwave Sensor
    • Abhishek Jha
    • Adam Lamęcki
    • Roberto Gomez-Garcia
    • Michał Mrozowski
    2020 Full text

    This paper presents a wireless planar microwave sensor operating at industrial scientific and medical (ISM) frequency for the detection of dielectric materials. The microwave sensor consists of a reader (ground defected microstrip coupled line) and a passive tag where a complementary split-ring resonator (CSRR) is made on the commercially available copper-foil. The CSRR is a peel-off type tag that is excited using the near field of microstrip coupled transmission line. The near field coupling, the low-cost passive tag design, and the high sensitivity (~250 MHz change per unit change in dielectric constant) make the proposed sensor wireless, cost-effective, and reliable.

  • Neoclassical Navier–Stokes Equations Considering the Gyftopoulos–Beretta Exposition of Thermodynamics
    • Janusz Badur
    • Michel Feidt
    • Paweł Ziółkowski
    2020 Full text ENERGIES

    The seminal Navier-Stokes equations were stated even before the creation of the foundations of thermodynamics and its first and second laws. There is a widespread opinion in the literature on thermodynamic cycles that the Navier-Stokes equations cannot be taken as a thermodynamically correct model of a local "working fluid", which would be able to describe the conversion of "heating" into "working" (Carnot's type cycles) and vice versa (Afanasjeva's type cycles). Also, it is overall doubtful that "cycle work is converted into cycle heat" or vice versa. The underlying reason for this situation is that the Navier-Stokes equations come from a time when thermodynamic concepts such as "internal energy" were still poorly understood. Therefore, this paper presents a new exposition of thermodynamically consistent Navier-Stokes equations. Following that line of reasoning-and following Gyftopoulos and Beretta's exposition of thermodynamics-we introduce the basic concepts of thermodynamics such as "heating" and "working" fluxes. We also develop the Gyftopoulos and Beretta approach from 0D into 3D continuum thermodynamics. The central role within our approach is played by "internal energy" and "energy conversion by fluxes." Therefore, the main problem of exposition relates to the internal energy treated here as a form of "energy storage." Within that context, different forms of energy are discussed. In the end, the balance of energy is presented as a sum of internal, kinetic, potential, chemical, electrical, magnetic, and radiation energies in the system. These are compensated by total energy flux composed of working, heating, chemical, electrical, magnetic, and radiation fluxes at the system boundaries. Therefore, the law of energy conservation can be considered to be the most important and superior to any other law of nature. This article develops and presents in detail the neoclassical set of Navier-Stokes equations forming a thermodynamically consistent model. This is followed by a comparison with the definition of entropy (for equilibrium and non-equilibrium states) within the context of available energy as proposed in the Gyftopoulos and Beretta monograph. The article also discusses new possibilities emerging from this "continual" Gyftopoulos-Beretta exposition with special emphasis on those relating to extended irreversible thermodynamics or Van's "universal second law".

  • Nested Kriging Surrogates for Rapid Multi-Objective Optimization of Compact Microwave Components
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2020 APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL

    A procedure for rapid EM-based multi-objective optimization of compact microwave components is presented. Our methodology employs a recently developed nested kriging modelling to identify the search space region containing the Pareto-optimal designs, and to construct a fast surrogate model. The latter permits determination of the initial Pareto set, further refined using a separate surrogate-assisted process. As an illustration, a three-section impedance transformer is designed for the best matching and minimum size. The set of trade-off designs is produced at the low computational cost of only a few hundred of high-fidelity EM simulations of the transformer circuit despite a large number of its geometry parameters.