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Politechniki Gdańskiej

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  • Comprehensive Investigation of Stoichiometry–Structure–Performance Relationships in Flexible Polyurethane Foams
    • Adam Olszewski
    • Paulina Kosmela
    • Adam Piasecki
    • Wiktoria Żukowska
    • Mariusz Szczepański
    • Paweł Wojtasz
    • Mateusz Barczewski
    • Roman Barczewski
    • Aleksander Hejna
    2022 Pełny tekst Polymers

    Polyurethane (PU) foams are versatile materials with a broad application range. Their performance is driven by the stoichiometry of polymerization reaction, which has been investigated in several works. However, the analysis was often limited only to selected properties and compared samples differing in apparent density, significantly influencing their performance. In the bigger picture, there is still a lack of comprehensive studies dealing with the stoichiometry impact on PU foams’ performance. Herein, flexible PU foams with a similar apparent density but differing in the isocyanate index (IIso) (from 0.80 to 1.20) were prepared. The stoichiometry–structure–performance relationships were investigated considering cellular and chemical structure, as well as the static and dynamic mechanical properties, thermal stability, thermal insulation, and acoustic performance. For IIso of 1.00, the biggest cell diameters of 274 µm were noted, which was 21–25% higher compared to 0.80 and 1.20 values. Increasing IIso reduced open cell content from 83.1 to 22.4%, which, combined with stiffening of structure (rise of modulus from 63 to 2787 kPa) resulting from crosslinking, limited the sound suppression ability around five times. On the other hand, it significantly strengthened the material, increasing tensile and compressive strength 4 and 13 times, respectively. Changes in the foams’ performance were also induced by the glass transition temperature shift from 6.1 to 31.7 ◦C, resulting from a greater extent of urethane groups’ generation and additional isocyanate reactions. Generally, the presented work provides important insights into preparing flexible PU foams and could be very useful for the future development of these materials.

  • Compressible gas density measurement by means of Fourier analysis of interferograms
    • Janusz Telega
    • Ryszard Szwaba
    • Małgorzata Śmiałek-Telega
    2022 Pełny tekst MEASUREMENT

    This paper describes a method for nonintrusive compressible gas density measurement by means of automated analysis of interferograms using FFT (Fast Fourier Transform), and its implementation using DFT (Discrete Fourier Transform), that does make this measurement technique a fairly valuable and accessible experimental method. The presented approach makes it possible to use the finite fringe setting of the interferometer, thus reducing adjustment time. In the process of analysis, the errors originating from the imperfections of optical elements are reduced, and a digital image of a virtual infinite setting of the instrument is generated. As described here, the method is extremely beneficial, but not limited to, flows with shock wave – boundary layer interactions. A result of density measured for a flow with shock wave is presented.

  • Computationally Efficient Surrogate-Assisted Design of Pyramidal-Shaped 3D Reflectarray Antennas
    • Peyman Mahouti
    • Mehmet Belen
    • Nurullah Calik
    • Sławomir Kozieł
    2022 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    Reflectarrays (RAs) have been attracting considerable interest in the recent years due to their appealing features, in particular, a possibility of realizing pencil-beam radiation patterns, as in the phased arrays, but without the necessity of incorporating the feeding networks. These characteristics make them attractive solutions, among others, for satellite communications or mobile radar antennas. Notwithstanding, available microstrip implementations are inherently narrow-band, and heavily affected by conductor and surface wave losses. RAs based on grounded dielectric layers offer improved performance and flexibility in terms of shaping the phase reflection response. In either case, a large number of variables (induced by the need for independent adjustment of individual unit cell geometries), and the necessity of handling several requirements, make the design process of reflectarrays a challenging endeavor. In particular, RA optimization is extremely expensive when conducted at the level of EM simulation models, otherwise necessary to ensure reliability. A practical solution is surrogate-assisted design with the metamodels constructed for the RA unit elements. Unfortunately, conventional modeling methods require large numbers of training data samples to render accurate surrogates, which turns detrimental to the optimization process efficiency. This work proposes an alternative approach with the unit element representations constructed using deep learning with automated adjustment of the model architecture. As a result, design-ready surrogates can be constructed using only a few hundred samples, and the total RA optimization cost is reduced to only a handful of equivalent EM analyses of the entire array. Our approach is validated using an RA incorporating 3D pyramidal-shaped elements and favorably compared to benchmark techniques. Experimental verification of the obtained design is discussed as well.

  • Computer Aided Telediagnostics System for Stoma Patients
    • Rafal Zawislak
    • Mariusz Szwoch
    • Grzegorz Granosik
    • Anna Miarka
    • Joanna Mik-Wojtczak
    • Michal Mik
    2022

    Stoma surgery may concern patients with colorectal cancer and inflammatory bowel disease. More than half of patients diagnosed with colon cancer present at an advanced stage, and palliative treatment may involve stoma formation. This type of surgery may change the patient’s life strongly, therefore they should receive special medical care. The paper presents the assumptions, concept, and architecture of the Stoma-Alert diagnosis support system, including the assessment of stoma complications and issuing recommendations for treatment and care. In particular, the telediagnosis subsystem, which is essential in the pandemic era, supports the assessment of stoma status on the basis of photos and symptoms provided remotely by the patient. The first experiences in the development of the system and interaction with it, both on the part of doctors and medical personnel, as well as the patients themselves, are also presented.

  • Computer-Aided Automated Greenery Design—Towards a Green BIM
    • Dominik Sędzicki
    • Jan Cudzik
    • Lucyna Nyka
    • Wojciech Bonenberg
    2022 Pełny tekst Sustainability

    Contemporary climate challenges are changing the architect’s awareness, which results in a broader spectrum of interest. The available software enables the design of vegetation, but it is often very limited and requires specialist knowledge. The available software allows the creation of individual solutions based on visual algorithms or writing scripts; however, they are still not common methods used in architecture and urban planning. The study proposes a new complex digital method of selection and design of greenery based on a new parameter spreadsheet. The proposition is supported by the review and investigation of the software used by designers identifying a range of tools for the design of greenery. The study proposes a theoretical model for automated plant selection and variations of possible greenery scenarios that could be integrated into the design process at the early stages of concept development.

  • Computer-Aided Detection of Hypertensive Retinopathy Using Depth-Wise Separable CNN
    • Imran Qureshi
    • Qaisar Abbas
    • Junhua Yan
    • Ayyaz Hussain
    • Kashif Shaheed
    • Abdul Rauf Baig
    2022 Pełny tekst Applied Sciences-Basel

    Hypertensive retinopathy (HR) is a retinal disorder, linked to high blood pressure. The incidence of HR-eye illness is directly related to the severity and duration of hypertension. It is critical to identify and analyze HR at an early stage to avoid blindness. There are presently only a few computer-aided systems (CADx) designed to recognize HR. Instead, those systems concentrated on collecting features from many retinopathy-related HR lesions and then classifying them using traditional machine learning algorithms. Consequently, those CADx systems required complicated image processing methods and domain-expert knowledge. To address these issues, a new CAD-HR system is proposed to advance depth-wise separable CNN (DSC) with residual connection and a linear support vector machine (LSVM). Initially, the data augmentation approach is used on retina graphics to enhance the size of the datasets. Afterward, this DSC approach is applied to retinal images to extract robust features. The retinal samples are then classified as either HR or non-HR using an LSVM classifier as the final step. The statistical investigation of 9500 retinograph images from two publicly available and one private source is undertaken to assess the accuracy. Several experimental results demonstrate that the CAD-HR model requires less computational time and fewer parameters to categorize HR. On average, the CAD-HR achieved a sensitivity (SE) of 94%, specificity (SP) of 96%, accuracy (ACC) of 95% and area under the receiver operating curve (AUC) of 0.96. This confirms that the CAD-HR system can be used to correctly diagnose HR.

  • Computer-assisted pronunciation training—Speech synthesis is almost all you need
    • Daniel Korzekwa
    • Jaime Lorenzo-trueba
    • Thomas Drugman
    • Bożena Kostek
    2022 Pełny tekst SPEECH COMMUNICATION

    The research community has long studied computer-assisted pronunciation training (CAPT) methods in non-native speech. Researchers focused on studying various model architectures, such as Bayesian networks and deep learning methods, as well as on the analysis of different representations of the speech signal. Despite significant progress in recent years, existing CAPT methods are not able to detect pronunciation errors with high accuracy (only 60% precision at 40%–80% recall). One of the key problems is the low availability of mispronounced speech that is needed for the reliable training of pronunciation error detection models. If we had a generative model that could mimic non-native speech and produce any amount of training data, then the task of detecting pronunciation errors would be much easier. We present three innovative techniques based on phoneme-to-phoneme (P2P), text-to-speech (T2S) and speech-to-speech (S2S) conversion to generate correctly pronounced and mispronounced synthetic speech. We show that these techniques not only improve the accuracy of three machine learning models for detecting pronunciation errors, but also help establish a new state-of-the-art in the field. Earlier studies have used simple speech generation techniques such as P2P conversion, but only as an additional mechanism to improve the accuracy of pronunciation error detection. We, on the other hand, consider speech generation to be the first-class method of detecting pronunciation errors. The effectiveness of these techniques is assessed in the tasks of detecting pronunciation and lexical stress errors. Non-native English speech corpora of German, Italian, and Polish speakers are used in the evaluations. The best proposed S2S technique improves the accuracy of detecting pronunciation errors in AUC metric by 41% from 0.528 to 0.749 compared to the state-of-the-art approach.

  • Con l’introduzione
    • Luciano Segreto
    2022

    Nata nel 1953 con l’obiettivo di portare l’Italia tra le nazioni avanzate anche in campo energetico, Eni rappresenta una delle principali imprese ad aver influenzato l’innovazione economica del Paese. La sua storia, legata a doppio filo alla figura di Enrico Mattei, consente di seguirne le traiettorie di sviluppo e le strategie di internazionalizzazione, nel quadro di un contesto in continua evoluzione. Questo volume ripercorre quasi cento anni di documenti: i saggi che lo compongono – frutto di ricerche originali, condotte in molti archivi, prima di tutto in quello di Eni – consentono di seguire da vicino il lungo percorso della storia energetica italiana.

  • CONCRETE MIX DESIGN USING ABRAMS AND BOLOMEY METHODS
    • Salem Abdelgader
    • Marzena Kurpińska
    • Jamal Khatib
    • Hakim S. Abdelgader
    2022 Pełny tekst BAU Journal - Science and Technology

    One way to reduce the consumption of cement is to optimize its use. Many known methods of concrete design, based on the Abrams law and the Bolomey method. Therefore, the authors chose those methods for analysis. The concrete composition with the assumed strength class, calculated by any method differs significantly. This applies especially to the cement content, as its content in the composition of concrete varies from 20 to 50%. The authors presented the computational analysis and the results of laboratory tests of concrete samples with the assumed compressive strengths of 25, 30, 35, 40 and 45 MPa and for two consistency classes plastic and liquid. Moreover, the tensile strength tests results of the samples due to splitting presented. The authors defined the scope of application of the calculation methods according to the Abrams and Bolomey methods.

  • Condition-Based Monitoring of DC Motors Performed with Autoencoders
    • Krzysztof Włódarczak
    • Łukasz Grzymkowski
    • Tomasz Stefański
    2022

    This paper describes a condition-based monitoring system estimating DC motor degradation with the use of an autoencoder. Two methods of training the autoencoder are evaluated, namely backpropagation and extreme learning machines. The root mean square (RMS) error in the reconstruction of successive fragments of the measured DC motor angular-frequency signal, which is fed to the input of autoencoder, is used to determine the health indicator (HI). A complete test bench is built using a Raspberry Pi system (i.e., motor driver controlling angular frequency) and Jetson Nano (i.e., embedded compute node to estimate motor degradation) to perform exploratory analysis of autoencoders for condition-based monitoring and comparison of several classical artificial intelligence algorithms. The experiments include detection of degradation of DC motor working in both constant and variable work points. Results indicate that the HI obtained with the autoencoders trained with the use of either training method is suitable for both work points. Next, an experiment with multiple autoencoders trained on each specific work point and running in parallel is reviewed. It is shown that, in this case, the minimum value of RMS error among all autoencoders should be taken as HI. Furthermore, it has been shown that there is a nearlinear relationship between HI and the difference between measured and reconstructed angular-frequency waveforms.

  • CONDITIONING FACTORS OF INDUSTRY-UNIVERSITY COOPERATION FROM THE PERSPECTIVE OF ENTERPRISES
    • Sylwia Sieracka
    • Marek Wirkus
    2022 Pełny tekst Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

    The cooperation between enterprises and universities varies in terms of character and intensity. Bearing in mind the potential represented by both parties, its low intensity is still noticed, and consequently, the lack or incomplete use of opportunities resulting from this cooperation. Current factors of industry-university cooperation were identified from the perspective of companies from biotechnology and pharmaceutical industries, as well as the conditions shaping these factors. The so-called 'overfactors' of cooperation with the university were distinguished, which should be particularly emphasized in order to intensify the cooperation. The dependence and change of factors on the stage of cooperation and industry were found, which may have an impact on the type of factors determining cooperation with universities. Współpraca przedsiębiorstw z uczelniami ma różny charakter i intensywność. Biorąc pod uwagę potencjał reprezentowany przez obie strony, wciąż zauważalny jest niski poziom jej intensywności, a co za tym idzie brak lub niepełne wykorzystanie szans wynikających z kooperacji obu podmiotów. W pracy przedstawiono aktualne czynniki współpracy przemysł-uczelnia z perspektywy przedsiębiorstw branży biotechnologicznej i farmaceutycznej oraz uwarunkowania kształtujące te czynniki. Wyróżniono tzw. „nadczynniki”, któremu należy poświęcić szczególną uwagę w celu zintensyfikowania współpracy przemysł-uczelnia. Ponadto stwierdzono zależność i zmianę czynników na poszczególnych etapach kooperacji oraz branży, co może mieć wpływ na rodzaj czynników determinujących tę współpracę.

  • Conditions for Multiple Acquisition of Echoes from Stationary Targets in Successive Transmissions of Active Sonars
    • Lech Kilian
    • Aleksander Schmidt
    • Mariusz Rudnicki
    2022 Pełny tekst Vibrations in Physical Systems

    In echolocation, the highest possible number of contacts with a detected target is clearly decisive on the possibilities of echo processing to optimise the estimation of distinctive characteristics of the observed target. In hydrolocation, the slow propagation of acoustic waves in water reduces the number of contacts of echosounders and sonars with detected targets. The article considers model conditions for acquiring multiple contacts with stationary targets detected by various sounding methods - with echosounders, classic active sonars and side looking sonars. Appropriate formulas explicitly linking the possible number of echo signals from the target in a specific geometry of the survey performed at the assumed speed are presented. These formulas are intuitively clear and not very complicated, but their value lies in the ability to instantly combine the vessel speed with the sounding effects, and may be a clear argument for imposing a low sounding speed, which make it difficult to steer the vessel.

  • Conductive printable electrodes tuned by boron-doped nanodiamond foil additives for nitroexplosive detection
    • Anna Dettlaff
    • Michał Rycewicz
    • Mateusz Ficek
    • Aleksandra Wieloszyńska
    • Mateusz Szala
    • Jacek Ryl
    • Robert Bogdanowicz
    2022 Pełny tekst MICROCHIMICA ACTA

    An efficient additive manufacturing-based composite material fabrication for electrochemical applications is reported. The composite is composed of commercially available graphene-doped polylactide acid (G-PLA) 3D printouts and surface- functionalized with nanocrystalline boron-doped diamond foil (NDF) additives. The NDFs were synthesized on a tantalum substrate and transferred to the 3D-printout surface at 200 °C. No other electrode activation treatment was necessary. Different configurations of low- and heavy-boron doping NDFs were evaluated. The electrode kinetics was analyzed using electro- chemical procedures: cyclic voltammetry and electrochemical impedance spectroscopy. The quasi-reversible electrochemical process was reported in each studied case. The studies allowed confirmation of the CV peak-to-peak separation of 63 mV and remarkably high heterogeneous electron transfer rate constant reaching 6.1 × 10 −2 cm s −1 for 10 k ppm [B]/[C] thin NDF fitted topside at the G-PLA electrode. Differential pulse voltammetry was used for effective 2,4,6-trinitrotoluene (TNT) detection at the studied electrodes with a 87 ppb limit of detection, and wide linearity range between peak current density and the analyte concentration (0.064 to 64 ppm of TNT). The reported electrode kinetic differences originate primarily from the boron-dopant concentration in the diamond and the various contents of the non-diamond carbon phase.

  • Consequences of russia’s military invasion of Ukraine for Polish-Ukrainian trade relations
    • Oleksandr Melnychenko
    • Tetiana Osadcha
    • Anatoliy Kovalyov
    • Valerii Matskul
    2022 Pełny tekst Journal of International Studies

    An accurate forecast of interstate trade volume allows for short-term and long-term planning, particularly deciding on state budget revenues, foreign exchange earnings, border arrangement, other infrastructure, migration and social policies. Hostilities are destructive so the russian military aggression against Ukraine in 2022 needs to be assessed in terms of its effects on key economic aspects of Polish-Ukrainian relations, as Poland has been the main economic, trade and social partner of Ukraine in recent years. This article analyses the trade dynamics between the two countries since 2005. It was found that since 2015 the main trends of this dynamics have changed. Monthly data from 2015 to 2021 were used for modelling and forecasting. Relevant SARIMA and Holt-Winters exponential smoothing models were built. These models forecast the volume of trade for the fourth quarter of 2021 and the first quarter of 2022. The relative errors of forecasting (compared to actual data) for October, November and December 2021 were as follows: according to the SARIMA model – 0.8%, 3.6% and 2.3%, respectively; for the Holt-Winters model – 1.9%, 3.6% and 0.7%, respectively. Given the expectations and consequences of russia’s military aggression against Ukraine, the average projected trade turnover between Ukraine and Poland was reduced by 20% per month for the first quarter of 2022. In comparison with the available actual (preliminary) data for January 2022, such a pessimistic forecast gave the following relative forecasting errors: according to the SARIMA model – 3.8%; according to the Holt-Winters model – approx. 1%

  • Consequences of suboptimal design of Building Integrated Photovoltaic Installation – a case study for Gdansk, Poland
    • Małgorzata Rudnicka
    • Ewa Klugmann-Radziemska
    2022 Pełny tekst Przegląd Elektrotechniczny

    The carried out analysis concerns 2 kWp building integrated photovoltaic installation (BIPV) at the Chemistry Faculty of Gdansk University of Technology. It was proven that the generated energy data for every month diverge significantly from the expected vales. It is corelated with suboptimal orientation of the installation itself, as well as with the tilt angle varying from optimal.

  • Consideration of the safety of bungee jumping in relation to mechanical properties of the instalation based on a jump accident in Gdynia
    • Agnieszka Tomaszewska
    • Paweł Kłosowski
    2022 Pełny tekst Engineering Transactions

    This paper considers a bungee jumping accident that took place in July 2019 in Gdynia, Poland. The authors conducted an investigation to determine the cause of the bungee rope failure. It was based on mechanical tests concerning the strength of the rope as well as the calculation of the force induced in the rope during the jump. Based on the theoretical and experimental results, the rope safety factor was estimated. It appeared to be three-fold lower than it is recommended in Polish regulations concerning ropes dedicated to lifting people for industrial and public purposes. However, no law regulations strictly concerning bungee installation makes it easy for accidents to occur.

  • Constant-Factor Approximation Algorithm for Binary Search in Trees with Monotonic Query Times
    • Dariusz Dereniowski
    • Izajasz Wrosz
    2022

    We consider a generalization of binary search in linear orders to the domain of weighted trees. The goal is to design an adaptive search strategy whose aim is to locate an unknown target vertex of a given tree. Each query to a vertex v incurs a non-negative cost ω(v) (that can be interpreted as the duration of the query) and returns a feedback that either v is the target or the edge incident to v is given that is on the path towards the target. The goal of the algorithm is to find a strategy that minimizes the worst-case total cost. We propose a constant-factor approximation algorithm for trees with a monotonic cost function. Such function is defined as follows: there exists a vertex r such that for any two vertices u,v on any path connecting r with a leaf it holds that if u is closer to r than v, then ω(u) ≥ ω(v). The best known approximation algorithm for general weight functions has the ratio of O{√{log n}} [Dereniowski et al. ICALP 2017] and it remains as a challenging open question whether constant-factor approximation is achievable in such case. This gives our first motivation towards considering monotonic cost functions and the second one lies in the potential applications.

  • Constrained multi-objective optimization of compact microwave circuits by design triangulation and pareto front interpolation
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2022 EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

    Development of microwave components is an inherently multi-objective task. This is especially pertinent to the design closure stage, i.e., final adjustment of geometry and/or material parameters carried out to improve the electrical performance of the system. The design goals are often conflicting so that the improvement of one normally leads to a degradation of others. Compact microwave passives constitute a representative case: reduction of the circuit footprint area is detrimental to electrical figures of merit (e.g., the operating bandwidth). Identification of the best available trade-off designs requires multi-objective optimization (MO). This is a computationally expensive task, especially when executed at the level of full-wave electromagnetic (EM) simulation. The computational complexity issue can be mitigated through the employment of surrogate modeling methods, yet their application is limited by a typically high nonlinearity of system responses, and the curse of dimensionality. In this paper, a novel technique for fast MO of compact microwave components is proposed, which allows for sequential rendition of the trade-off designs using triangulation of the already available Pareto front as well as rapid refinement algorithms. Our methodology is purely deterministic; in particular, it does not rely on population-based nature-inspired procedures. The three major benefits are low computational cost, possibility of handling explicit design constraints, and a capability of producing a visually uniform representation of the Pareto front. The algorithm is demonstrated using a compact branch-line coupler and a three-section impedance matching transformer. In both cases, considerable savings are obtained over the benchmark, here, the state-of-the-art surrogate-assisted MO technique.

  • Constructive Controllability for Incompressible Vector Fields
    • Sergey Kryzhevich
    • Eugene Stepanov
    2022

    We give a constructive proof of a global controllability result for an autonomous system of ODEs guided by bounded locally Lipschitz and divergence free (i.e. incompressible) vector field, when the phase space is the whole Euclidean space and the vector field satisfies so-called vanishing mean drift condition. For the case when the ODE is defined over some smooth compact connected Riemannian manifold, we significantly strengthen the assertion of the known controllability theorem in absence of nonholonomic constraints by proving that one can find a control steering the state vector from one given point to another by using the observations of only the state vector, i.e., in other words, by changing slightly the vector field, and such a change can be made small not only in uniform, but also in Lipschitz (i.e. C^1) topology.

  • Contemporary Architectural Design in the Context of Historic Remains: The Case of the Old City of Gdańsk
    • Antoni Taraszkiewicz
    • Karol Grębowski
    • Karolina Taraszkiewicz
    • Jarosław Przewłócki
    2022 Pełny tekst Heritage and Society

    This article presents several examples of modern developments designed to preserve and coexist with fragments of historic brick buildings. These building projects each faced a similar task; to save and display the historical urban fabric, but they differed significantly in how they chose to achieve that goal. Not all of the projects presented in this study meet the requirements of the Venice Charter equally well. In this field, the solution often means choosing the “lesser evil”. Each of the projects presents a unique example of interdisciplinary research used to solve complex construction problems. Numerical analysis using the finite element method (including the damage model based on plastic degradation adopted for brick walls)was carried out for one of the projects.

  • Context of Digitalized Employment for Older Adults with Autism Spectrum Disorder in the New Normal
    • Elias Mpofu
    • Michał Tomczak
    • Nathan Hutson
    • Lucy Gafford
    • Ronfang Zhan
    2022

    Employers are actively considering how to normalize remote work technology across different industries. The residual risk of coronavirus disease-19 (COVID-19) will necessarily lower the bar for allowing some workers to stay remote on a more permanent basis. This is based on the realization that many essential jobs can be teleworked while retaining or enhancing productivity. The decisions employers make regarding future work arrangements are based upon assumptions and evidence collected over the course of the pandemic, which are framed in a neurotypical context. This chapter examines the potential benefits and risks of mainstreaming telecommuting or remote working for older adults with autism spectrum disorder (ASD). In doing so, this chapter considers different work and job redesign tools, which might be necessary to enable successful remote working including assistive technology and low-cost solutions based on publicly available software. Moreover, we consider technology-based solutions aimed at improving the long-term work well-being of older adults with ASD. Finally, we examine career stage and transition considerations with older adults with ASD in the context of the new normal.

  • Continuum models for pantographic blocks with second gradient energies which are incomplete
    • Maximilian Stiltz
    • Francesco dell'Isola
    • Ivan Giorgio
    • Victor Eremeev
    • Georg Ganzmuller
    • Stefan Hiermaier
    2022 Pełny tekst MECHANICS RESEARCH COMMUNICATIONS

    We postulate a deformation energy for describing the mechanical behavior of so called pantographic blocks, that is bodies constituted by stacking of layers of pantographic sheets. We remark that the pantographic effect is limited in the plane of pantographic sheets and therefore only the second derivatives of transverse displacements along the pantographic fibers appear in the chosen deformation energy. We use this novel energy to predict the behavior of pantographic blocks when subjected to : (i) compression and traction test, (ii) torsion, (iii) shear and (iv) bending. A linearization of the energy shows one floppy mode in addition to the rigid body motions, assuming perfect pivots, similar to pantographic sheets.

  • Contribution of dynamic vehicle loads to pavement failure
    • Dawid Ryś
    2022

    Pavement surfaces are not ideally even, which causes dynamic loads of vehicle axles. Distribution of dynamic loads of a given axle is similar to normal distribution and can be described by static load and dynamic load coefficient. The dynamic load coefficient depends on road profile, vehicle speed, properties of suspensions and static load of axle. While for a given road section road profile remains constant, vehicle speed and suspension properties are subject to limited variations, the static loads of particular axle vary significantly. The weigh-inmotion systems are the source of data on static loads, which are characterized by axle load spectra. The axle load spectra are the key data input for pavement design. The article presents a new approach to inclusion of the dynamic loads in axle load spectra. The theoretical explanation is supported by sample calculations. A one-kilometer road section was selected for calculations and its profile was measured using laser road surface profilograph. The dynamic loads were then calculated using the quarter car model and parameters appropriate for heavy vehicle suspensions. This part of calculations proved that dynamic loads significantly increase for less loaded axles. Dynamic axle load spectra were calculated based on static axle load spectra and function of dynamic load coefficient. The load equivalency factors and truck factors were calculated using the fourth power equation and considering both static and dynamic axle load spectra. Contribution of dynamic loads to pavement failure equals up to 19% for the considered example of road profile, which is characterized by IRI = 1.54 m/km.

  • Control of the bridge span vibration with high coefficient passive damper. Theoretical consideration and application
    • Krzysztof Żółtowski
    • Anna Banaś
    • Mikołaj Binczyk
    • Przemysław Kalitowski
    2022 Pełny tekst ENGINEERING STRUCTURES

    The research was carried out due to the problem of vibration on the lively pedestrian drawbridge across the Motlawa River in the city of Gdansk. In the design stage, the main span of the footbridge showed unfavorable dynamic properties, which may create a comfort problem for pedestrians. The first vertical bending eigenfrequency was recognized as 1.64 Hz. The original design of the footbridge was equipped with a driving cylinder to operate opening of the drawbridge. It was installed between the abutment and the pylon (integrated part of the span). Based on numerical calculations, it turned out that its high overdamping ratio can raise the value of the first vertical natural frequency to the level where pedestrian action has a low influence on the dynamic excitation of the span. It should be noted, the solution does not affect the behavior of the structure under static loads. Therefore, it was decided to modify the existing hydraulic driving cylinder to become a damper also. Analytical and numerical modeling was performed to establish an appropriate range of damper constant values. Finally, this idea was implemented in the structure. The theoretically defined effects of introducing a high ratio damper have been practically confirmed during the field test. The first vertical natural frequency of the span was shifted from 1.64 Hz to 3.1 Hz. The paper presents the work related to the solution of a specific case. However, the presented idea can be used in a wide spectrum of structures subjected to dynamic excitation. In practice, an external damper enables the change of a ”static scheme” of the structure in the selected range of dynamic loads. This idea has a sense only in the case where response amplitude from dynamic loads is smaller than from the static action.

  • Control Strategy of a Five-Phase Induction Machine Supplied by the Current Source Inverter With the Third Harmonic Injection
    • Marcin Morawiec
    • Filip Wilczyński
    2022 Pełny tekst IEEE TRANSACTIONS ON POWER ELECTRONICS

    In the five-phase induction machine (IM), it is possible to better use the electromagnetic circuit than in the three-phase IM. This requires the use of an adequate converter system which will be supplied by an induction machine. The electric drive system described, in this article, includes the five-phase induction machine supplied by the current source inverter (CSI). The proposed novelty—not presented previously—is the control system structures for the five-phase IM, which is supplied by CSI. The proposed control systems allow for independent control of IM state variables in the first and the second system plane to inject the third harmonic. However, the third harmonic must be suitably associated with the fundamental harmonic. In the proposed solution, the machine vector model is not transformed into the (d–q) coordinate system that is connected to the rotor flux vector but utilizes the stationary system (α–β). The nonlinear model linearization is based on the demonstrated nonlinear variables transformation for i-orthogonal (α–β) (i) planes. Voltage control is applied to the control system structure. The control variables of the five-phase IM are the voltage in the dc link and the angular speed of the output current vector. In the control strategy, the control variables are determined for both system planes. Therefore, the transformation of these control variables to the dc link of CSI is proposed. The proposed control structure allows for independent control of variables in the first and second system planes. It leads to the possibility to increase the value of electromagnetic torque up to 12% for the five-phase IM, which has not been used before in the case of the machine supplied by the CSI. All theoretical issues are confirmed by experimental tests in the 5.5 kW five-phase IM.

  • Contr-rotating eccentric-mass rotors used as exciters of sinusoidal forces applied to elastically supported bodies
    • Krzysztof Lipiński
    • Mirosław Gerigk
    • Rafał Hein
    • Grzegorz Banaszek
    2022

    The work focuses on aspects of multibody dynamics. Investigated object is a mass driven by rotations of an inertial shaker. Resulting vibrational set consists of two counter-rotating identically-unbalanced rotors. Since the mass centres of the rotors do not coincide with the axes of their rotations, significant centrifugal forces arise during rotations. As both rotors are identically unbalanced, the inter-axial force components balance each other, and only the summed transverse components generate the requested resultant of the sinusoidal-variable exciting force. Abovementioned description refers to a simplified theory of the force generation, since it omits several significant aspects which are difficult to their on-hand estimations, e.g., inertial terms created by the inertia products and gyroscopic effects. These effects, reasonable omitted in case of the stationary fixed shakers, are investigated in the paper, as the vibration-based angular motion of the excited base is significant and interacts with the relative spin motion of the rotors. What is more, variability of the angular speed of the spin should be considered, if power of the implemented drives is limited. Also, the angular and the linear kinematics resulting of the two motions are recombined, e.g. centrifugal terms resulting of rotation are modified by accelerations of transport motion of the base. Taking all of the facts under consideration, effective forces of the real exciter can differ from these which was initially requested, and thus, numerical verification of dynamics of the exciter is recommended, especially, if amplitudes of the resulting vibrations are significant. According to the indicated aspects, multibody model of the exciter is proposed and described in the paper. Simulated behaviours of the model are compared with behaviours a reference model interpreted as a rigid body driven by an ideal external exciter able to perfectly create a force which is described by a purely harmonic mathematical formula. Difference of the obtained results and applicability of the investigated exciter is discussed.

  • Conversion of waste biomass into activated carbon and evaluation of environmental consequences using life cycle assessment
    • Muhammad Amin
    • Hussain Hamad Shah
    • Amjad Iqbal
    • Marek Krawczuk
    • Ur Zia Rahman Faroogi
    • Adeel Zia
    2022 Pełny tekst Applied Sciences-Basel

    In this article, activated carbon was produced from Lantana camara and olive trees by H3PO4 chemical activation. The prepared activated carbons were analyzed by characterizations such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, X-ray diffraction, thermogravimetric analysis, and Fourier transform infrared spectroscopy. H3PO4 is used as an activator agent to create an abundant pore structure. According to EDX analysis, the crystalline structure destroys and increases the carbon content of the olive tree and Lantana camara by 77.51 and 76.16%, respectively. SEM images reveal a porous structure formed as a result of H3PO4 activation. The Brunauer–Emmett–Teller (BET) surface area of the olive tree and Lantana camara activated carbon was 611.21 m2/g and 167.47 m2/g, respectively. The TGA analysis of both activated carbons shows their thermal degradation starts at 230 °C but fully degrades at temperatures above 450 °C. To quantify the potential environmental implications related to the production process of the activated carbon (AC) from olive trees, the life cycle assessment (LCA) environmental methodology was employed. For most of the tested indicators, chemical activation using H3PO4 showed the greatest ecological impacts: the ozone layer depletion potential (42.27%), the acidification potential (55.31%), human toxicity (57.00%), freshwater aquatic ecotoxicity (85.01%), terrestrial ecotoxicity (86.17%), and eutrophication (92.20%). The global warming po-tential (5.210 kg CO2 eq), which was evenly weighted between the phases, was shown to be one of the most significant impacts. The total energy demand of the olive tree’s AC producing process was 70.521 MJ per Kg.

  • Convolutional Neural Networks for C. Elegans Muscle Age Classification Using Only Self-Learned Features
    • Bartosz Czaplewski
    • Mariusz Dzwonkowski
    • Damian Panas
    2022 Pełny tekst Journal of Telecommunications and Information Technology

    Nematodes Caenorhabditis elegans (C. elegans) have been used as model organisms in a wide variety of biological studies, especially those intended to obtain a better understanding of aging and age-associated diseases. This paper focuses on automating the analysis of C. elegans imagery to classify the muscle age of nematodes based on the known and well established IICBU dataset. Unlike many modern classification methods, the proposed approach relies on deep learning techniques, specifically on convolutional neural networks (CNNs), to solve the problem and achieve high classification accuracy by focusing on non-handcrafted self-learned features. Various networks known from the ImageNet Large Scale Visual Recognition Challenge (ILSVRC) have been investigated and adapted for the purposes of the C. elegans muscle aging dataset by applying transfer learning and data augmentation techniques. The proposed approach of unfreezing different numbers of convolutional layers at the feature extraction stage and introducing different structures of newly trained fully connected layers at the classification stage, enable to better fine-tune the selected networks. The adjusted CNNs, as featured in this paper, have been compared with other state-of-art methods. In anti-aging drug research, the proposed CNNs would serve as a very fast and effective age determination method, thus leading to reductions in time and costs of laboratory research.

  • Cooperativity of Halogen- and Chalcogen-Bonding Interactions in the Self-Assembly of 4‑Iodoethynyl- and 4,7-Bis(iodoethynyl)benzo-2,1,3-chalcogenadiazoles: Crystal Structures, Hirshfeld Surface Analyses, and Crystal Lattice Energy Calculations
    • Jan Alfuth
    • Beata Zadykowicz
    • Barbara Wicher
    • Katarzyna Kazimierczuk
    • Tadeusz Połoński
    • Teresa Olszewska
    2022 Pełny tekst CRYSTAL GROWTH & DESIGN

    Several new 4-iodoethynyl- and 4,7-bis- (iodoethynyl)benzo-2,1,3-chalcogenadiazoles were prepared, and a comprehensive analysis of the most prominent secondary bonding interactions responsible for the crystal self-assembly was performed using X-ray diffraction. The presence of both the iodoethynyl and chalcogenadiazole moieties allows an evaluation of the preference of these molecules to aggregate through either chalcogen- or halogen-bonding interactions in the solid state. The crystal structures of the compounds revealed that their solid-state arrangements are influenced by the nature of the chalcogen atom: for the crystals of the thiadiazoles studied, the C−I···N halogen bonds were preferred, whereas in the corresponding 2,1,3-selenadiazole derivatives, the self-complementary [Se···N]2 supramolecular synthons together with the C−I···N halogen-bonding interactions determined the molecular self-assembly. Furthermore, in the case of the bis(iodoethynyl) derivative the crystal structurewas additionally influenced by the C−I···π(ethynyl) halogen bond. Hirshfeld surface and 2D fingerprint plot analyses were used to demonstrate the intermolecular interactions and intercontact distributions. Also, the total lattice energies were calculated using the CRYSTAL09 and CrystalExplorer programs. They both indicated intermolecular π···π interactions as the forces of substantial contribution to the total lattice energies.

  • Core–shell excitation of isoxazole at the C, N, and O K-edges – an experimental NEXAFS and theoretical TD-DFT study
    • Tomasz Wąsowicz
    • Ivan Ljubić
    • Antti Kivimäki
    • Robert Richter
    2022 Pełny tekst PHYSICAL CHEMISTRY CHEMICAL PHYSICS

    The near-edge X-ray absorption fine structure (NEXAFS) spectra of the gas-phase isoxazole molecule have been measured by collecting total ion yields at the C, N, and O K-edges. The spectral structures have been interpreted using time-dependent density functional theory (TD-DFT) with the short-range corrected SRC2-BLYP exchange–correlation functional. Experimental and calculated energies of core excitations are generally in good agreement, and the nature of observed core-excitation transitions has been elucidated. The experimental C 1s, N 1s, and O 1s core electron binding energies (CEBEs) have additionally been estimated from another yield measurement where the neutral fragments in high-Rydberg (HR) states were ionized by the electric field. For comparison, theoretical CEBEs have been calculated at the DM06-2X//mixed basis set level. We have also calculated the vibrationally resolved spectra pertaining to the lowest C 1s and N 1s core-excited roots in the Franck–Condon–Herzberg–Teller (FCHT) approximation. These spectra correlate well with the observed spectral features and have proven useful in resolving certain ambiguities in the assignment of the low-lying C 1s NEXAFS bands.

  • Corporate social responsibility and project management: towards a better understanding of their relationship
    • Piotr Sliż
    • Magdalena Popowska
    • Julia Jarzyński
    2022 Pełny tekst e-mentor

    The main purpose of this article is to identify the fields of convergence, if any, between two management concepts and business practices, namely Corporate Social Responsibility (CSR) and Project Management (PM). To achieve the formulated goal, a systematic literature review (SLR), including bibliometric analysis, LOESS regression analysis, and text mining, was performed. This analysis allowed us to distinguish five categories corresponding to the distinctive, related research areas combining CSR and PM constructs. Within these categories we were able to identify the most important characteristics of the linkages between both concepts.

  • Correlation between Compressive Strength and Heat of Hydration of Cement Mortars with Siliceous Fly Ash
    • Aleksandra Kuryłowicz-Cudowska
    2022 Pełny tekst Minerals

    This paper presents the results of calorimetric and strength tests of mortars with ordinary Portland cement and two substitution rates (10 and 20%) of cement by siliceous fly ash. The prepared samples were cured under isothermal conditions at four different temperatures: 23, 33, 43 and 53 °C. Heat of hydration was measured using an isothermal calorimeter dedicated to monitor the hydration process of cementitious composites such as paste, mortar and concrete. Thermal data were recorded continuously for 7 days, while compression tests were performed at 6 h and 1, 2, 5, 7 and 14 days of hardening. The studies proved that the amount of heat released correlates with the early-age strength of 50 mm mortar cubes. In the case of samples cured at 23 and 53 °C, a linear relationship between the heat of hydration and compressive strength was observed. The high value of the coefficient of determination (R2) allows one to estimate the mortar compressive strength after 7 and 14 days based on hydration heat tests conducted at standard temperature (23 °C), regardless of the percentage of siliceous fly ash. The increased curing temperatures do not guarantee a high correlation between compressive strength and the amount of heat released.

  • Corrigendum to “T1 relaxation time callibration in magnetic resonance imaging using nanodiamond phantoms” [Phys Med 94 (2022) S119–S120/EPV029]
    • Monika Kosowska
    • Anna Sękowska-Namiotko
    • Agnieszka Sabisz
    • Mateusz Ficek
    • Małgorzata Szczerska
    2022 PHYSICA MEDICA

    The authors want to update the incorrect funding information. The correct funding note is: “The authors acknowledge the financial support from Gdańsk University of Technology by the 4/2020/IDUB/III.4.1/Tc grant under the Technetium Talent Management Grants ‘Excellence Initiative – Research University’. The financial support from Gdańsk University of Technology by the 1/2021/IDUB/II.2/Np grant under NEPTUNIUM Enhancing Baltic Region Research Cooperation is gratefully acknowledged.The DS Programs of Faculty of Electronics, Telecommunications and Informatics of Gdańsk University of Technology are acknowledged. This work has also been supported by the DS funds of Faculty of Telecommunications, Computer Science and Electrical Engineering, Bydgoszcz University of Science and Technology".

  • Corrosion degradation monitoring of ship stiffened plates using guided wave phase velocity and constrained convex optimization method
    • Beata Zima
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    2022 Pełny tekst OCEAN ENGINEERING

    The study presents an experimental investigation on the corrosion degradation level assessment using nondestructive wave-based methods. The degradation level of ship structural elements has been assessed in two different ways. The first one is based on the spectral decomposition and zero-crossing incorporated reconstruction of the dispersion curve approach of the antisymmetric Lamb wave mode and the best matching of the theoretical solution. The second approach was based on searching for a solution to the convex optimization problem. In the first case, the plate thickness is assumed to be constant and the phase velocity reconstructed curve is fitted to match the best solution in the all considered frequency domain. In the second case, the assumption about the varying plate thickness is set and the optimal thickness distribution resulting in any times of wave flight is defined.

  • Corrosion monitoring as a factor increasing the safety of hydrotechnical infrastructure
    • Robert Mazur
    • Pawel Stefanek
    • Juliusz Orlikowski
    2022 Pełny tekst Archives of Civil Engineering

    Water distribution systems at KGHM S.A. are of great importance for the efficient production of copper and environmental protection. For failures leading to perforation and leakage, the corrosion processes are responsible. This paper aims to assess corrosion on the basis of the analysis of the exposure of the Hydrotechnical Plant pipelines. To this end, the system of transfer and deposition of post-flotation waste as well as the circulation of industrial water in the process of copper ore enrichment are described. Water sources as well as inflows and outflows in the water system are indicated; corrosion hazards are determined. Water is obtained from mines; it is often contaminated during the copper ore mining process. The chemical analysis of industrial (technological) water and sludge water resulting from the sedimentation of post-flotation waste showed a high concentration of inorganic salts which are responsible for the corrosive processes. Furthermore, tests were carried out to determine the corrosion rate. Additionally, possible methods to reduce corrosion have been proposed, i.e., a corrosion monitoring system has been described as a tool for reducing production interruptions and environmental pollution

  • Cost-Efficient Optical Fronthaul Architectures for 5G and Future 6G Networks
    • Abdulhalim Fayad
    • Tibor Cinkler
    • Jacek Rak
    • Balazs Sonkoly
    2022

    Fifth-generation and Beyond (5GB) wireless networks have introduced new centralized architectures such as cloud radio access network (CRAN), which necessitate extremely high-capacity low latency Fronthaul (FH). CRAN has many advantageous features in terms of cost reduction, performance enhancement, ease of deployment, and centralization of network management. Nevertheless, designing and deploying a cost-efficient FH is still a stumbling block against mobile network operators (MNOs) that aim to deploy 5GB in a cost-effective manner. Many technologies have been proposed as a candidate for 5GB FH. Optical networking is the best long-term solution for overcoming the connection barrier between the radio access domain and the core network of 5GB. Therefore, we focus on optical technologies such as point-to-point optical fiber (P2P), passive optical networks (PON), and free-space optics (FSO). With that in mind, we propose in this paper an integer linear program (ILP) that results in a minimal total cost of ownership (TCO) considering both capital expenditure (Capex) and operational expenditure (Opex). For the scalability issue, we propose a heuristic algorithm to solve the problem for large network instances. In order to evaluate the applicability of the proposed framework, we run the simulations to compare different FH architectures for two deployment areas (dense and sparse).

  • COVID‐19: A systematic review and update on prevention, diagnosis, and treatment
    • Hooman Aghamirza Moghim Aliabadi
    • Reza Eivazzadeh‐Keihan
    • Arezoo Beig Parikhani
    • Sara Fattahi Mehraban
    • Ali Maleki
    • Sepideh Fereshteh
    • Masoume Bazaz
    • Ashkan Zolriasatein
    • Bahareh Bozorgnia
    • Saman Rahmati
    • Fatemeh Saberi
    • Zeinab Yousefi Najafabadi
    • Shadi Damough
    • Sara Mohseni
    • Hamid Salehzadeh
    • Vahid Khakyzadeh
    • Hamid Madanchi
    • Gholam Ali Kardar
    • Payam Zarrintaj
    • Mohammad Saeb
    • Masoud Mozafari
    2022 Pełny tekst MedComm

    Since the rapid onset of the COVID-19 or SARS-CoV-2 pandemic in the world in 2019, extensive studies have been conducted to unveil the behavior and emission pattern of the virus in order to determine the best ways to diagnosis of virus and thereof formulate effective drugs or vaccines to combat the disease. The emergence of novel diagnostic and therapeutic techniques considering the multiplicity of reports from one side and contradictions in assessments from the other side necessitates instantaneous updates on the progress of clinical investigations. There is also growing public anxiety from time to time mutation of COVID-19, as reflected in considerable mortality and transmission, respectively, from delta and Omicron variants. We comprehensively review and summarize different aspects of prevention, diagnosis, and treatment of COVID-19. First, biological characteristics of COVID-19 were explained from diagnosis standpoint. Thereafter, the preclinical animal models of COVID-19 were discussed to frame the symptoms and clinical effects of COVID-19 from patient to patient with treatment strategies and in-silico/computational biology. Finally, the opportunities and challenges of nanoscience/nanotechnology in identification, diagnosis, and treatment of COVID-19 were discussed. This review covers almost all SARS-CoV-2-related topics extensively to deepen the understanding of the latest achievements (last updated on January 11, 2022).

  • COVID-19 severity forecast based on machine learning and complete blood count data
    • Barbara Klaudel
    • Aleksander Obuchowski
    • Roman Karski
    • Bartosz Rydziński
    • Patryk Jasik
    • Zdzisław Kowalczuk
    2022

    Proper triage of COVID-19 patients is a key factor in eective case management, especially with limited and insucient resources. In this paper, we propose a machine-aided diagnostic system to predict how badly a patient with COVID-19 will develop disease. The prognosis of this type is based on the parameters of commonly used complete blood count tests, which makes it possible to obtain data from a wide range of patients.We chose the four-tier nursing care category as the outcome variable. In this paper, we compare traditional tree-based machine learning models with approaches based on neural networks. The developed tool achieves a weighted average F1 score of 73% for a three-class COVID-19 severity forecast. We show that the complete blood count test can form the basis of a convenient and easily accessible method of predicting COVID-19 severity. Of course, such a model requires meticulous validation before it is proposed for inclusion in real medical procedures.

  • COVID-19 severity forecast based on machine learning and complete blood count data
    • Barbara Klaudel
    • Aleksander Obuchowski
    • Roman Karski
    • Bartosz Rydziński
    • Patryk Jasik
    • Zdzisław Kowalczuk
    2022

    Proper triage of COVID-19 patients is a key factor in eective case management, especially with limited and insucient resources. In this paper, we propose a machine-aided diagnostic system to predict how badly a patient with COVID-19 will develop disease. The prognosis of this type is based on the parameters of commonly used complete blood count tests, which makes it possible to obtain data from a wide range of patients.We chose the four-tier nursing care category as the outcome variable. In this paper, we compare traditional tree-based machine learning models with approaches based on neural networks. The developed tool achieves a weighted average F1 score of 73% for a three-class COVID-19 severity forecast. We show that the complete blood count test can form the basis of a convenient and easily accessible method of predicting COVID-19 severity. Of course, such a model requires meticulous validation before it is proposed for inclusion in real medical procedures.

  • Crack Detection in Metallic Surfaces Based on Dumbbell-Shaped Defected Ground Structures in Microstrip Technology
    • Zahra Shaterian
    • Michał Mrozowski
    2022 Pełny tekst

    In this paper, a novel crack detection sensor using a microstrip loaded with a Dumbbell-Shaped Defected Ground Structure (DS-DGS) is proposed. The sensing element is etched in the ground plane of a microstrip line and it is easy to fabricate. The electromagnetic (EM) field of the microstrip couples to the DS-DGS, thus demonstrating a bandstop behavior. It is shown that in the presence of a crack in a metallic surface underneath the sensor, the resonance frequency of the DS-DGS is shifted. This frequency shift can be used for crack sensing in metallic surfaces. The proposed sensor exhibits a good sensitivity above 260 MHz shift for a crack with a 200 µm width at the relatively low operating frequency of around 2 GHz.

  • Crack Mouth Opening Displacement for EH36 Shipbuilding Steel Measurements
    • Jakub Kowalski
    • Janusz Kozak
    2022

    The dataset titled EH36 steel for shipbuilding (plate thicnkness 50mm) - CMOD - force record, a0/W = 0.6 contains CMOD (Crack Mouth Opening Displacement) - Force record which is the base for evaluation of fracture toughness of structural steel. Bend specimens witch Bx2B section (B= 50mm), and relative initial crack length a0 / W = 0.60 were used. The test was carried out at ambient temperature in accordance to ISO 12135 standard. The dataset can be useful in calibration of numerical material models which includes ductile failure. It can also be use as a reference data in comparison of toughness designated for carbon steels.

  • Crack Mouth Opening Displacement for EH36 Shipbuilding Steel Measurements Dataset
    • Jakub Kowalski
    • Janusz Kozak
    2022 Pełny tekst

    The dataset titled EH36 steel for shipbuilding (plate thickness 50 mm) – CMOD – force record, a0/W=0.6 contains a CMOD (Crack Mouth Opening Displacement) – Force record which is the base for evaluation of the fracture toughness of structural steel. Bend specimens with a Bx2B section (B = 50 mm), and relative initial crack length a0/W=0.60 were used. The test was carried out at ambient temperature in accordance with the ISO 12135 standard. The dataset can be useful in the calibration of numerical material models which includes ductile failure. It can also be use as reference data in the comparison of the toughness designations of carbon steels.

  • Creating a radiological database for automatic liver segmentation using artificial intelligence.
    • Sergii Girnyi
    • Tomasz Dziubich
    • Adam Brzeski
    • Jan Cychnerski
    • Dariusz Świetlik
    • Jakub Woźniak
    • Weronika Szczecińska
    • Janusz Jaśkiewicz
    • Jacek Zielinski
    2022 EJSO-EUR J SURG ONC

    Imaging in medicine is an irreplaceable stage in the diagnosis and treatment of cancer. The subsequent therapeutic effect depends on the quality of the imaging tests performed. In recent years we have been observing the evolution of 2D to 3D imaging for many medical fields, including oncological surgery. The aim of the study is to present a method of selection of radiological imaging tests for learning neural networks.

  • Creating a Remote Choir Performance Recording Based on an Ambisonic Approach
    • Bartłomiej Mróz
    • Piotr Odya
    • Bożena Kostek
    2022 Pełny tekst Applied Sciences-Basel

    The aim of this paper is three-fold. First, the basics of binaural and ambisonic techniques are briefly presented. Then, details related to audio-visual recordings of a remote performance of the Academic Choir of the Gdańsk University of Technology are shown. Due to the COVID-19 pandemic, artists had a choice, namely, to stay at home and not perform or stay at home and perform. In fact, staying at home brought in the possibility of creating and developing art at home while working online. During the first months of lock-down, the audience was satisfied with music performances that were fairly far from the typical experience of a real concert hall. Then, more advanced technology was brought to facilitate joint rehearsal and performance of better quality, including multichannel sound and spatialization. At the same time, spatial music productions benefited from the disadvantage of remote rehearsal by creating immersive experiences for the audience based on ambisonic and binaural techniques. Finally, subjective tests were prepared and performed to observe performers’ attention behavior divided between the conductor and music notation in the network-like environment. To this end, eye-tracking technology was employed. This aspect is related to the quality of experience (QoE), which in the performance area–and especially in remote mode–is essential.

  • Creating new voices using normalizing flows
    • Piotr Biliński
    • Tom Merritt
    • Abdelhamid Ezzerg
    • Kamil Pokora
    • Sebastian Cygert
    • Kayoko Yanagisawa
    • Roberto Barra-Chicote
    • Daniel Korzekwa
    2022 Pełny tekst

    Creating realistic and natural-sounding synthetic speech remains a big challenge for voice identities unseen during training. As there is growing interest in synthesizing voices of new speakers, here we investigate the ability of normalizing flows in text-to-speech (TTS) and voice conversion (VC) modes to extrapolate from speakers observed during training to create unseen speaker identities. Firstly, we create an approach for TTS and VC, and then we comprehensively evaluate our methods and baselines in terms of intelligibility, naturalness, speaker similarity, and ability to create new voices. We use both objective and subjective metrics to benchmark our techniques on 2 evaluation tasks: zero-shot and new voice speech synthesis. The goal of the former task is to measure the precision of the conversion to an unseen voice. The goal of the latter is to measure the ability to create new voices. Extensive evaluations demonstrate that the proposed approach systematically allows to obtain state-of-the-art performance in zero-shot speech synthesis and creates various new voices, unobserved in the training set. We consider this work to be the first attempt to synthesize new voices based on mel-spectrograms and normalizing flows, along with a comprehensive analysis and comparison of the TTS and VC modes.

  • Critical Review on Robust Speed Control Techniques for Permanent Magnet Synchronous Motor (PMSM) Speed Regulation
    • Kifayat Ullah
    • Jaroslaw Guzinski
    • Adeel Mirza
    2022 Pełny tekst ENERGIES

    The permanent magnet synchronous motor (PMSM) is a highly efficient energy saving machine. Due to its simple structural characteristics, good heat radiation capability, and high efficiency, PMSMs are gradually replacing AC induction motors in many industrial applications. The PMSM has a nonlinear system and lies on parameters that differ over time with complex high-class dynamics. To achieve the excessive performance operation of a PMSM, it essentially needs a speed controller for providing accurate speed tracking, slight overshoot, and robust disturbance repulsion. Therefore, this article provides an overview of different robust control techniques for PMSMs and reviews the implementation of a speed controller. In view of the uncertainty factors, such as parameter perturbation and load disturbance, the H¥ robust control strategy is mainly reviewed based on the traditional control techniques, i.e., robust H¥ sliding mode controller (SMC), and Hinfinity robust current controller based on Hamilton–Jacobi Inequality (HJI) theory. Based on comparative analysis, this review simplifies the development trend of different control technologies used for a PMSM speed regulation system.

  • Cryptocurrencies as a speculative asset. How much uncertainty is included in cryptocurrency price?
    • Krystian Zawadzki
    • Tayyaba Ahsan
    2022

    The aim of this paper is to examine the relationship between uncertainty indices (Geopolitical Uncertainty Index and Global Economic Policy Uncertainty Index) and cryptocurrencies. In order to conduct research, the authors collected the data on the major cryptocurrencies (Bitcoin, Ethereum, Tether, Dogecoin and USD coin) which account for 78% of the total market cap. Using panel OLS regression, this study finds that Bitcoin and Ethereum are not a safe haven for global economic policy uncertainty, but other cryptocurrencies serve as safe hedges against this uncertainty. On the contrary, these cryptocurrencies are safe hedges against the uncertainty of geopolitical risk.

  • Crystal Structure of N-(2-Benzoyl-4,5-dimethoxyphenethyl)-2-phenylacetamide
    • Petja Marinova
    • Stoyanka Nikolova
    • Anna Dołęga
    • Anife Ahmedova
    2022 Pełny tekst Molbank

    The crystal structure of N-(2-benzoyl-4,5-dimethoxyphenethyl)-2-phenylacetamide indicates that the compound crystallizes in the monoclinic C2/c space group with eight molecules in the unit cell. The heteroatoms from the amide group form a chain of intermolecular N-H ··· O hydrogen bonds propagating along the b axis. The carbonyl group from the benzoyl substituent participates in short contacts with two H-atoms from the ethyl or phenyl groups.

  • CSR and innovation or CSR as non-technological innovation
    • Magdalena Popowska
    2022

    This chapter investigates the relationship between Corporate Social Responsibility (CSR) and innovation process. There is an ongoing discussion in the literature regarding this relationship, in particular on its one- or bidirectional nature and possible antecedents or mediating factors. This research addresses this gap and aims to provide more conceptual clarity and synthesize the different types of relationships between CSR and innovation. We conducted a systematic literature review to investigate the state of art in this field. Our findings confirm the bidirectional relationship between CSR and innovation and the existence of the mediating factors in this relation. CSR itself can be also understood as non-technological innovation since it implies a myriad of possible solutions and organizational or marketing changes.

  • CSR at HEIs: Between Ignorance, Awareness and Knowledge
    • Julita Wasilczuk
    • Magdalena Popowska
    2022 Pełny tekst Problemy Zarządzania

    The paper focuses on CSR education in Higher Education Institutions. It analyzes current approaches to this education and the enhancements already deployed in the international perspective. The main aim is to conceptualize CSRS education forms within the context of technology-oriented HEIs and propose the model for this education. This model has also been partially verified using the cases of four technical universities. This research uses qualitative and quantitative research methods. The literature review is applied to trace HEIs’ educational and organizational CSR commitment methods. Based on this review, we proposed a model of CSRS education in HEIs. Using this model, we checked to what extent its elements are used in four technical universities from Latvia, Lithuania, Ukraine and Poland. For this purpose, educational programs at universities were analyzed. We also confronted the activity of these universities with the students’ knowledge about CSRS. The results of the survey conducted among 3,424 students from these universities contributed to elaborating on this aspect. Findings: The results confirm that students are ignorant of CSR, even those studying at business faculties. What is surprising, even those students who are business owners do not demonstrate a high level of knowledge about CSR. Universities, on the other hand, do not offer the possibility of eliminating this ignorance. Meanwhile, we believe they can do so not only through the standing-alone CSRS education but also by including CSR in other courses and by giving a good example. Due to language barriers, the submitted model was only partially verified at selected universities. We are also aware that the described situation may be one-sided as the four cases presented in this study are homogeneous, as they represent technical universities, so only one profile among a variety of universities’ profiles (technical versus humanities versus economic). Bearing in mind the current level of implementation of education in the area of CSR and the results of the research carried out, we propose a model of education that includes three pillars: a good example of a university (socially responsible university), is responsible managers education (RME) and raising awareness among students of non-business faculties (ASR). At the same time, we indicated alarge gap between the educational needs in the area of CSRS and the offer of four technical universities.