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Gdańsk University of Technology

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  • Compatibility of Sustainable Mater-Bi/poly(ε-caprolactone)/cellulose Biocomposites as a Function of Filler Modification
    • Aleksander Hejna
    • Mateusz Barczewski
    • Paulina Kosmela
    • Olga Mysiukiewicz
    • Adam Piasecki
    • Agnieszka Tercjak
    2023 Full text Materials

    Despite their popularity and multiplicity of applications, wood–polymer composites (WPCs) still have to overcome particular issues related to their processing and properties. The main aspect is the compatibility with plant-based materials which affects the overall performance of the material. It can be enhanced by strengthening the interfacial adhesion resulting from physical and/or chemical interactions between the matrix and filler, which requires introducing a compatibilizer or a proper modification of one or both phases. Herein, the impact of cellulose filler modifications with varying contents (1–10 wt%) of hexamethylene diisocyanate (HDI) on the compatibility of Mater-Bi/poly(ε-caprolactone) (PCL)-based biocomposites was evaluated. An analysis of surface wettability revealed that the filler modification reduced the hydrophilicity gap between phases, suggesting compatibility enhancement. It was later confirmed via microscopic observation (scanning electron microscopy (SEM) and atomic force microscopy (AFM)), which pointed to the finer dispersion of modified particles and enhanced quality of the interface. The rheological analysis confirmed increased system homogeneity by the reduction in complex viscosity. In contrast, thermogravimetric analysis (TGA) indicated the efficient modification of filler and the presence of the chemical interactions at the interface by the shift of thermal decomposition onset and the changes in the degradation course.

  • Complexity Issues on of Secondary Domination Number
    • Joanna Raczek
    2023 Full text ALGORITHMICA

    In this paper we study the computational complexity issues of the problem of secondary domination (known also as (1, 2)-domination) in several graph classes. We also study the computational complexity of the problem of determining whether the domination and secondary domination numbers are equal. In particular, we study the influence of triangles and vertices of degree 1 on these numbers. Also, an optimal algorithm for finding a minimum secondary dominating set in trees is presented.

  • Computational Analysis of Transformational Organisational Change with Focus on Organisational Culture and Organisational Learning: An Adaptive Dynamical Systems Modeling Approach
    • Lars Rass
    • Jan Treur
    • Wioleta Kucharska
    • Anna Monika Wiewiora
    2023

    Transformative Organisational Change becomes more and more significant both practically and academically, especially in the context of organisational culture and learning. However computational modeling and formalization of organisational change and learning processes are still largely unexplored. This chapter aims to provide an adaptive network model of transformative organisational change and translate a selection of organisational learning and change processes into computationally modeled processes. Additionally, it sets out to connect the dynamic systems view of organisations to self-modeling network models. The creation of the model and the implemented mechanisms of organisational processes are based on extrapolations of an extensive literature study and grounded in related work in this field, and then applied to a specified hospital-related case scenario in the context of safety culture. The model was evaluated by running several simulations and variations thereof. The results of these were investigated by qualitative analysis and comparison to expected emergent behaviour based on related available academic literature. The simulations performed confirmed the occurrence of an organisational transformational change towards a constant learning culture by offering repeated and effective learning and changes to organisational processes. Observations about various interplays and effects of the mechanism have been made, and they exposed that acceptance of mistakes as a part of learning culture facilitates transformational change and may foster sustainable change in the long run.. Further, the model confirmed that the self-modeling network model approach applies to a dynamic systems view of organisations and a systems perspective of organisational change. The created model offers the basis for the further creation of self-modeling network models within the field of transformative organisational change and the translated mechanisms of this model can further be extracted and reused in a forthcoming academic exploration of this field.

  • Computational Complexity and Its Influence on Predictive Capabilities of Machine Learning Models for Concrete Mix Design
    • Patryk Ziółkowski
    2023 Full text Materials

    The design of concrete mixtures is crucial in concrete technology, aiming to produce concrete that meets specific quality and performance criteria. Modern standards require not only strength but also eco-friendliness and production efficiency. Based on the Three Equation Method, conventional mix design methods involve analytical and laboratory procedures but are insufficient for contemporary concrete technology, leading to overengineering and difficulty predicting concrete properties. Machine learning-based methods offer a solution, as they have proven effective in predicting concrete compressive strength for concrete mix design. This paper scrutinises the association between the computational complexity of machine learning models and their proficiency in predicting the compressive strength of concrete. This study evaluates five deep neural network models of varying computational complexity in three series. Each model is trained and tested in three series with a vast database of concrete mix recipes and associated destructive tests. The findings suggest a positive correlation between increased computational complexity and the model’s predictive ability. This correlation is evidenced by an increment in the coefficient of determination (R2) and a decrease in error metrics (mean squared error, Minkowski error, normalized squared error, root mean squared error, and sum squared error) as the complexity of the model increases. The research findings provide valuable insights for increasing the performance of concrete technical feature prediction models while acknowledging this study’s limitations and suggesting potential future research directions. This research paves the way for further refinement of AI-driven methods in concrete mix design, enhancing the efficiency and precision of the concrete mix design process.

  • Computational Simulation of the Effects of Different Culture Types and Leader Qualities on Mistake Handling and Organisational Learning
    • Natalie Samhan
    • Jan Treur
    • Wioleta Kucharska
    • Anna Monika Wiewiora
    2023

    This chapter investigates computationally the following research hypotheses: (1) Higher flexibility and discretion in organisational culture results in better mistake management and thus better organisational learning, (2) Effective organisational learning requires a transformational leader to have both high social and formal status and consistency, and (3) Company culture and leader’s behavior must align for the best learning effects. Computational simulations of the introduced adaptive network were analyzed in different contexts varying in organisation culture and leader characteristics. Statistical analysis results proved to be significant and supported the research hypotheses. Ultimately, this chapter provides insight into how organisations that foster a mistake-tolerant attitude in alignment with the leader can result in significantly better organisational learning on a team and individual level.

  • Computationally-Efficient Statistical Design and Yield Optimization of Resonator-Based Notch Filters Using Feature-Based Surrogates
    • Sławomir Kozieł
    • Tanveer Haq Ul
    2023 Full text Scientific Reports

    Modern microwave devices are designed to fulfill stringent requirements pertaining to electrical performance, which requires, among others, a meticulous tuning of their geometry parameters. When moving up in frequency, physical dimensions of passive microwave circuits become smaller, making the system performance increasingly susceptible to manufacturing tolerances. In particular, inherent inaccuracy of fabrication processes affect the fundamental operating parameters, such as center frequency or bandwidth, which is especially troublesome for narrow-band structures, including notch filters. The ability to quantify the effects of tolerances, and—even more—to account for these in the design process, are instrumental in making the designs more reliable, and to increase the likelihood that adequate operation is ensured despite manufacturing errors. This paper proposes a simple yet computationally efficient and reliable procedure for statistical analysis and yield optimization of resonator-based notch filters. Our methodology involves feature-based surrogate models that can be established using a handful of training data points, and employed for rapid evaluation of the circuit fabrication yield. Furthermore, a yield optimization procedure is developed, which iteratively sets up a sequence of feature-based models, constructed within local domains relocated along the optimization path, and uses them as predictors to find a robust (maximum yield) design at a low computational cost. The presented approach has been demonstrated using two complementary split ring resonator (CSRR)-based notch filters. The cost of statistical design is about a hundred of EM simulations of the respective filter, with yield evaluation reliability corroborated through EM-based Monte Carlo analysis.

  • Computer-Aided Diagnosis of COVID-19 from Chest X-ray Images Using Hybrid-Features and Random Forest Classifier
    • Kashif Shaheed
    • Piotr Szczuko
    • Qaisar Abbas
    • Ayyaz Hussain
    • Mubarak Albathan
    2023 Full text Healthcare

    In recent years, a lot of attention has been paid to using radiology imaging to automatically find COVID-19. (1) Background: There are now a number of computer-aided diagnostic schemes that help radiologists and doctors perform diagnostic COVID-19 tests quickly, accurately, and consistently. (2) Methods: Using chest X-ray images, this study proposed a cutting-edge scheme for the automatic recognition of COVID-19 and pneumonia. First, a pre-processing method based on a Gaussian filter and logarithmic operator is applied to input chest X-ray (CXR) images to improve the poorquality images by enhancing the contrast, reducing the noise, and smoothing the image. Second, robust features are extracted from each enhanced chest X-ray image using a Convolutional Neural Network (CNNs) transformer and an optimal collection of grey-level co-occurrence matrices (GLCM) that contain features such as contrast, correlation, entropy, and energy. Finally, based on extracted features from input images, a random forest machine learning classifier is used to classify images into three classes, such as COVID-19, pneumonia, or normal. The predicted output from the model is combined with Gradient-weighted Class Activation Mapping (Grad-CAM) visualisation for diagnosis. (3) Results: Our work is evaluated using public datasets with three different train–test splits (70–30%, 80–20%, and 90–10%) and achieved an average accuracy, F1 score, recall, and precision of 97%, 96%, 96%, and 96%, respectively. A comparative study shows that our proposed method outperforms existing and similar work. The proposed approach can be utilised to screen COVID-19-infected patients effectively. (4) Conclusions: A comparative study with the existing methods is also performed. For performance evaluation, metrics such as accuracy, sensitivity, and F1-measure are calculated. The performance of the proposed method is better than that of the existing methodologies, and it can thus be used for the effective diagnosis of the disease.

  • Computer-Aided Greenery Design—Prototype Green Structure Improving Human Health in Urban Ecosystem
    • Dominik Sędzicki
    • Jan Cudzik
    • Lucyna Nyka
    2023 Full text International Journal of Environmental Research and Public Health

    Increasing population and urbanization, with climate change consequences, such as rising temperatures, influence public health and well-being. The search to improve the quality of life in cities becomes one of the priority objectives. A solution can be found in the role of greenery in an urban environment and its impact on human health. This opens a path toward experimentation on microclimate green structures that can be inserted into dense urban spaces providing human and environmental benefits. The article proposes an automated greenery design method combined with rapid prototyping for such interventions. A theoretical analysis of the problem preceded the introduction of the method. The research process was developed in accordance with the main objectives of the CDIO framework (Conceive, Design, Implement, and Operate) with the SiL (Software in the Loop) and HiL (Hardware in the Loop) methods. Moreover, the applied test model allows for complex evaluation in order to ensure quality and directions for further development.

  • Concentration‐Induced Hetero‐Valent Partial‐Inverse Occupation of Infrared Phosphor
    • Dominik Kreft
    • Jia‐Yu Hsu
    • Ren-jei Chung
    • Yen‐Ling Kuo
    • Chun Che Lin
    • Natalia Majewska
    • Sebastian Mahlik
    • Mu-huai Fang
    2023 Advanced Optical Materials

    Infrared luminescent materials have evoked much attention from chemists and material scientists. Although substantial progress is made in materials design, the luminescent mechanism remains ambiguous in the complex structures, presenting major barriers to developing novel infrared luminescent materials. Herein, this study aims to deliberate a complete discussion on infrared phosphors with concentration-induced hetero-valent partial-inverse occupation. High-resolution synchrotron X-ray diffraction and Raman spectroscopy reveal the subtle structural change in LiGa5(1−x)O8:5xCr3+. Besides, Cr K-edge wavelet analysis and extended X-ray absorption fine structure illustrate the impact of Cr in the second shell of another Cr ion and the practical coordination of Ga and Cr ions. Furthermore, unexpected two-center Cr3+ emissions and the Cr–Cr pair emission are observed at high Cr concentrations. Variation between the zero-phonon line and N-line at different temperatures is demonstrated. Finally, the structural and luminescent properties are comprehensively discussed, providing the origin of the unexpected Cr2 emission. This study not only provides insight into the hetero-valent partial-inverse occupation process in inorganic materials but also sheds light on developing novel infrared luminescent materials.

  • Concept of an Innovative System for Dimensioning and Predicting Changes in the Coastal Zone Topography Using UAVs and USVs (4DBatMap System)
    • Oktawia Specht
    • Mariusz Specht
    • Andrzej Stateczny
    • Cezary Specht
    2023 Full text Electronics

    This publication is aimed at developing a concept of an innovative system for dimensioning and predicting changes in the coastal zone topography using Unmanned Aerial Vehicles (UAVs) and Unmanned Surface Vehicles (USVs). The 4DBatMap system will consist of four components: 1. Measurement data acquisition module. Bathymetric and photogrammetric measurements will be carried out with a specific frequency in the coastal zone using a UAV equipped with a Global Navigation Satellite System (GNSS)/Inertial Navigation System (INS), Light Detection And Ranging (LiDAR) and a photogrammetric camera, as well as a USV equipped with a GNSS Real Time Kinematic (RTK) receiver and a MultiBeam EchoSounder (MBES). 2. Multi-sensor geospatial data fusion module. Low-altitude aerial imagery, hydrographic and LiDAR data acquired using UAVs and USVs will be integrated into one. The result will be an accurate and fully covered with measurements terrain of the coastal zone. 3. Module for predicting changes in the coastal zone topography. As part of this module, a computer application will be created, which, based on the analysis of a time series, will determine the optimal method for describing the spatial and temporal variability (long-term trend and seasonal fluctuations) of the coastal zone terrain. 4. Module for imaging changes in the coastal zone topography. The final result of the 4DBatMap system will be a 4D bathymetric chart to illustrate how the coastal zone topography changes over time.

  • Conditions for increasing the recognition of degradation in thermal-flow diagnostics, taking into account environmental legal aspects
    • Marta Drosińska-Komor
    • Jerzy Głuch
    • Katarzyna Brzezińska-gołębiewska
    • Michał Piotrowicz
    • Paweł Ziółkowski
    2023 Full text Journal of Power Technologies

    The ever-increasing demand for electricity and the need for conventional sources to cooperate with renewable ones generates the need to increase the efficiency and safety of the generation sources. Therefore, it is necessary to find a way to operate existing facilities more efficiently with full detection of emerging faults. These are the requirements of Polish, European and International law, which demands that energy facilities operate with the highest efficiency and meet a number of restrictive requirements. In order to improve the operation of steam power plants of electric generating stations, thermal-fluid diagnostics have been traditionally used, and in this paper a three-hull steam turbine, having a high-pressure, a medium-pressure and a low-pressure part, has been selected for analysis. The turbine class is of the order of 200 MW electric. Genetic algorithms (GA) were used in the process of creating the diagnostic model. So far, they have been used for diagnostic purposes in gas turbines, and no work has been found in the literature using GA for the diagnostic process of such complex objects as steam turbines located in professional manufacturing facilities. The use of genetic algorithms allowed rapid acquisition of global extremes, that is efficiency and power of the unit. The result of the work undertaken is the possibility to carry out a full diagnostic process, meaning detection, localization and identification of single and double degradations. In this way 100 % of the main faults are found, but there are sometimes additional ones, and these are not perfectly identified especially for single time detection. Thus, the results showed that with a very high success rate the simulated damage to the geometrical elements of the steam turbine under study is found.

  • CONDITIONS OF THE GREEN TRANSFORMATION. THE CASE OF THE EUROPEAN UNION
    • Katarzyna Cheba
    • Iwona Bąk
    • Michał Pietrzak
    2023 Full text Technological and Economic Development of Economy

    The main purpose of the paper is to identify the factors that determine the course of green transformation and to assess the current stage and possible directions of change in subsequent years in EU countries. The literature lacks comprehensive studies that show the impact of diverse types of factors on the course of green transformation. For this purpose, two perspectives of the research – economic and environmental – are usually taken into account. This paper also proposes to take social factors into account. The empirical verification was conducted using green growth indicators that are published by the OECD that were compared with factors identified from the literature review. Taxonomic (synthetic) measure of development applying the Weber median and correlation coefficient were used for searching for relationships between the identified groups of indicators described both the changes in the dimension of green growth (internal factors of green transformation) and changes in the dimension of contextual indicators (so-called external factors). The proposed way of combining the results obtained from these two methods of data analysis is also new to research in this field. Its aim is an in-depth exploration of the issue, which enables a 2-step verification of the results obtained.

  • Connected early-career experiences of equality in academia during the pandemic and beyond: Our liminal journey
    • Frederike Scholz
    • Joanna Szulc
    2023 Full text Gender, Work and Organization

    In this paper, we draw on our subjective experiences as two female early-career academics during the global COVID-19 pandemic. While we acknowledge that the pandemic had negative implications for many female scholars due to compulsory telework or increased family responsibilities, we also want to shed light on the empowering experiences shaped by collegial support that became an important part of our pandemic story. We build on the theory of liminality to explain how the events triggered by the pandemic allowed us to break out of our uncomfortable occupational limbo (i.e., feeling “locked-in” to the identity of a foreign-born PhD graduate) and, through creating a kind of equality, resulted in some unique opportunities and challenges. During these difficult times, shaped by an increasing fear of us or our family catching COVID-19, we embarked on a betwixt-and-between state that allowed us to grow as academics as a part of a collective.

  • Constrained aerodynamic shape optimization using neural networks and sequential sampling
    • Pavankumar Koratikere
    • Leifur Leifsson
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2023

    Aerodynamic shape optimization (ASO) involves computational fluid dynamics (CFD)-based search for an optimal aerodynamic shape such as airfoils and wings. Gradient-based optimization (GBO) with adjoints can be used efficiently to solve ASO problems with many design variables, but problems with many constraints can still be challenging. The recently created efficient global optimization algorithm with neural network (NN)-based prediction and uncertainty (EGONN) partially alleviates this challenge. A unique feature of EGONN is its ability to sequentially sample the design space and continuously update the NN prediction using an uncertainty model based on NNs. This work proposes a novel extension to EGONN that enables efficient handling of nonlinear constraints and a continuous update of the prediction and prediction uncertainty data sets. The proposed algorithm is demonstrated on constrained airfoil shape optimization in transonic flow and compared against state-of-the-art GBO with adjoints. The results show that the proposed constrained EGONN algorithm yields comparable optimal designs as GBO at a similar computational cost.

  • Construction of a simulation model of goods delivery in international road transportation taking into account the functioning efficiency of logistics supply chain
    • Ievgenii Lebid
    • Nataliia Luzhanska
    • Iryna Lebid
    • Alexander Mazurenko
    • Inesa Halona
    • Anatolii Horban
    • Iryna Mykhailenko
    • Ievgen Medvediev
    • Tetiana Sotnikova
    2023 Full text Eastern-European Journal of Enterprise Technologies [ Восточно-Европейский журнал передовых технологий ]

    The object of this study is the process of goods delivery in international road transport using various types of logistics chains. The problem being solved is due to the need to develop recommendations for exporters of goods to reformat or design new supply chains during wartime. The expediency of organizing foreign trade operations by the cargo owners' own forces or with the involvement of enterprises providing logistics consulting services is considered. A simulation model of goods delivery in international road traffic was built and implemented in the GPSS World simulation automation package. The model involves the optimization of organizational and technological processes related to the activity of both a separate link and the entire supply chain. The study takes into account the components of the time characteristics of the performance of preparatory work when establishing cooperation with institutions and organizations, as well as the direct service of the exporter. The application of the developed model in practical activities will provide an opportunity for exporters to obtain information about the duration and reliability of the stages of a foreign trade operation and the feasibility of involving consulting enterprises in cooperation. At the same time, the simulation results reflect the performance indicators of the proposed supply chains when delivering goods by road transport along various routes. The proposed simulation model will make it possible to reduce the time spent searching for links in the formation of a supply chain by 8–12 %, and the duration of a foreign trade operation by 10–14 %. Thus, the reliability of cooperation with intermediary organizations will increase by 8–11 %

  • Contemporary multifunctional buildings towards a sustainable development of the housing environment
    • Antoni Taraszkiewicz
    • Mateusz Gerigk
    2023 Full text Środowisko Mieszkaniowe

    Development of contemporary urban centers depends on the basis that buildings present more and more complex structures in terms of size and purpose. They are referred to as multifunctional buildings. This aspiration has its origins in the development of urban centers and in the desire to optimize the built-up areas. The article presents the theory of the approach to the design of multifunctional buildings with a focus on the residential function and the nature of environment that these objects shape. The optimization of the design model shows the multi-threaded nature in the pursuit of determining its functional features. This paper presents a model based approach to the design of multifunctional structures with the residential function based on theoretical considerations and practical knowledge. Examples show an upward trend in the construction of residential complexes. The presented research results show an original, systemic approach to the issue, from the urban context to the architectural environment, which aims to improve the design model constituting a part of larger functional complexes. The integration of systems theory, architectural design and spatial execution provides the methodological framework of the work.

  • Continuous blood pressure monitoring by photoplethysmography - signal preprocessing requirements based on blood flow modelling
    • Artur Poliński
    2023 Full text PHYSIOLOGICAL MEASUREMENT

    Objective. The aim of the study is to investigate the effect of the signal sampling frequency and low-pass filtering on the accuracy of the localisation of the fiducial points of the photoplethysmographic signal (PPG), and thus on the estimation of the blood pressure (i.e. the accuracy of the estimation). Approach. Statistical analysis was performed on 3,799 data samples taken from a publicly available database. Four PPGfiducial points of each sample signal were examined in the study. Main results. Simulation suggests that for noise-free data, cubic spline interpolation causes the sampling frequency (in the considered range of 62.5–500 Hz) to have only limited influence on localisation of the fiducial point. Better results were obtained for the pulse transit time (PTT)than pulse arrival time (PAT) approach. The acceptable filter band depends on the selected fiducial point and PAT or PTT approach. The best results were obtained for the tangent fiducial point. Significance. The presented results make it possible to estimate the minimum requirements for the sampling frequency and filtering of the PPG signal in order to obtain a reliable estimation of blood pressure

  • Contra Bellum: Bell's Theorem as a Confusion of Languages
    • Marek Czachor
    2023 Full text ACTA PHYSICA POLONICA A

    Bell's theorem is a conflict of mathematical predictions formulated within an infinite hierarchy of mathematical models. Inequalities formulated at level k ∈ Z are violated by probabilities at level k+1. We are inclined to think that k=0 corresponds to the classical world, while k=1 — to the quantum one. However, as the k=0 inequalities are violated by k=1 probabilities, the same relation holds between k=1 inequalities violated by k=2 probabilities, k=-1 inequalities violated by k=0 probabilities, and so forth. By accepting the logic of the Bell theorem, can we prove by induction that nothing exists?

  • Controlling crystallites orientation and facet exposure for enhanced electrochemical properties of polycrystalline MoO3 films
    • Konrad Trzciński
    • Zuzanna Zarach
    • Mariusz Szkoda
    • Andrzej Nowak
    • Katarzyna Berent
    • Mirosław Sawczak
    2023 Full text Scientific Reports

    This study focuses on the development and optimization of MoO3 films on commercially available FTO substrates using the pulsed laser deposition (PLD) technique. By carefully selecting deposition conditions and implementing post-treatment procedures, precise control over crystallite orientation relative to the substrate is achieved. Deposition at 450 °C in O2 atmosphere results in random crystallite arrangement, while introducing argon instead of oxygen to the PLD chamber during the initial stage of sputtering exposes the (102) and (011) facets. On the other hand, room temperature deposition leads to the formation of amorphous film, but after appropriate post-annealing treatment, the (00k) facets were exposed. The deposited films are studied using SEM and XRD techniques. Moreover, electrochemical properties of FTO/MoO3 electrodes immersed in 1 M AlCl3 aqueous solution are evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The results demonstrate that different electrochemical processes are promoted based on the orientation of crystallites. When the (102) and (011) facets are exposed, the Al3+ ions intercalation induced by polarization is facilitated, while the (00k) planes exposure leads to the diminished hydrogen evolution reaction overpotential.

  • Conversion of waste biomass to designed and tailored activated chars with valuable properties for adsorption and electrochemical applications
    • Katarzyna Januszewicz
    • Paweł Kazimierski
    • Anita Cymann-Sachajdak
    • Paulina Hercel
    • Beata Barczak
    • Monika Wilamowska-Zawłocka
    • Dariusz Kardas
    • Justyna Łuczak
    2023 Full text ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

    Waste biomass, a renewable energy source, is inexpensive material that has great potential in sorp-tion and electrochemical application. The selected waste materials (corncobs, coconut shells, wal-nuts, and pistachio husks) allow to close the production cycle and enable material recycling, which are important aspects in the hierarchy of waste management. The proposed methodology for pro-duction and activation of biochars can be used industrially due to highly porous structure, devel-oped surface area and sorption ability of the obtained activated carbons (AC). A significant increase (from 4 up to more than 10 times) in specific surface area (SSA) is observed for all samples after the CO2 activation process (0.5 h at 800°C) up to 725 m2⸱g-1 for corncobs, 534.9 m2⸱g-1 for pistachio husks, 523 m2⸱g-1 for coconut shells, and 393 m2⸱g-1 for walnut husks. The highest value of SSA is achieved for the AC derived from corncobs. This material is evaluated for use as an adsorbent, re-vealing 99% removal of Rhodamine B (dye/AC ratio of 0.0017) and 69% removal of chromium (dye/AC ratio of 0.0028). Based on the adsorption kinetics analysis, it is demonstrated that the Cr (VI) undergoes physical adsorption, while RhB - chemisorption. In addition, corncob-derived AC exhibits superior electrochemical performance in 6 M KOH compared to the non-activated biochar. A specific capacitance of 70 F⸱g-1 at 5 A⸱g-1 is achieved, along with outstanding rate capability (45 F⸱g-1 at 50 A⸱g-1) and cycling stability (94% at 10 A⸱g-1 after 10 000 cycles). In contrast, the non-activated sample shows only 34 F⸱g-1 at 5 A⸱g-1 and 13 F⸱g-1 at 50 A⸱g-1, with a stability of 91.4%.

  • Core loss resistance impact on sensorless speed control of an induction motor using hybrid adaptive sliding mode observer
    • Tadele Ayana
    • Lelisa Wogi
    • Marcin Morawiec
    2023 Full text Archives of Electrical Engineering

    Induction motors (IMs) experience power losses when a portion of the input power is converted to heat instead of driving the load. The combined effect of copper losses, core losses, and mechanical losses results in IM power losses. Unfortunately, the core losses in the motor, which have a considerable impact on its energy efficiency, are not taken into account by the generally employed dynamic model in the majority of the studies. Due to this, the motor rating often corresponds to the worst-case load in applications, but the motor frequently operates below rated conditions. A hybridized model reference adaptive system (MRAS) with sliding mode control (SMC) is used in this study for sensorless speed control of an induction motor with core loss, allowing the motor to operate under a variety of load conditions. As a result, the machine can run at maximum efficiency while carrying its rated load. By adjusting the -axis current in the − reference frame in vector-controlled drives, the system's performance is enhanced by running the motor at its optimum flux. Regarding the torque and speed of both induction motors with and without core loss, the Adaptive Observer Sliding Mode Control (AOSMC) has been constructed and simulated in this case. The AOSMC with core loss produced good performance when the proposed controller was tested.

  • Corporate social responsibility and forward default risk mediated by financial performance and goodwill
    • Muhammad Mushafiq
    • Błażej Prusak
    • Magdalena Markiewicz
    2023 JOURNAL OF CLEANER PRODUCTION

    In today’s business environment, corporate social responsibility (CSR) has become an increasingly significant factor for firms. This study is driven by the motivation to add to the current literature by investigating the mediating elements that explain the relationship between CSR and forward default risk. In this paper, we attempt to identify the important mediators and give a more comprehensive explanation of this connection by a thorough assessment of the available literature and empirical research. This study explored the relationship between corporate social responsibility and forward default risk through financial performance and goodwill. The study sample consisted of constituents of Standard and Poor’s (S&P) 500 index. It was found from the results of the study that corporate social responsibility has an effect on forward default risk through goodwill and financial performance. The direct and indirect effect of CSR on forward default risk is more enhanced in a 1-year period, as the effect on 3-year forward default risk is lower. Similar results are found during period of economic upswing; however, there is no mediation in CSR and 1-year forward default risk by goodwill. This study has some policy implications. Overall, the study adds to the growing body of literature (stakeholder theory and corporate finance theory) on the relationship between CSR and the financial aspect of firms and highlights the importance of considering CSR in financial decision-making and risk management.

  • Corrosion degradation impact on mechanical properties of structural steel
    • Krzysztof Wołoszyk
    • Yordan Garbatov
    2023 Full text

    Recently, extensive research was conducted regarding the impact of corrosion degradation on the mechanical properties of structural steel. Studies show that at the material level, the microstructure is somewhat unchanged due to corrosion degradation. However, the corrosion causes pits and structural surface irregularities that consequently impact the mean stress-strain response of typical coupon specimens subjected to tensile loading. Regrettably, the current industrial standards do not account for that phenomenon and treat the impact of corrosion degradation as the uniform thinning of the structural steel. The presented work aims to acknowledge the recent studies regarding the impact of corrosion degradation on the mechanical properties of structural steel, to show future perspectives and to outline the need for more research in this field.

  • Corrosion mechanisms in columns for atmospheric distillation of crude oil
    • Juliusz Orlikowski
    • Radosław Gospoś
    • Tomasz Olczak
    • Kazimierz Darowicki
    2023 Ochrona przed Korozją

    The paper presents the most common corrosion processes occurring in the columns for atmospheric distillation of crude oil. It describes the mechanisms leading to formation of the chemical compounds, which contribute to corrosion phenomena. The main technological factors influencing corrosion processes have been indicated. The paper also presents the interactions between particular corrosion mechanisms resulting in acceleration or inhibition of corrosion rate.

  • Corrosion Properties of Dissimilar AA6082/AA6060 Friction Stir Welded Butt Joints in Different NaCl Concentrations
    • Aleksandra Laska
    • Marek Szkodo
    • Łukasz Pawłowski
    • Grzegorz Gajowiec
    2023 Full text International Journal of Precision Engineering and Manufacturing-Green Technology

    A solid-state friction stir welding method which is increasingly used in the marine and shipbuilding industry, has been developed to produce welds with high mechanical properties. In seawater, the oxide layer of aluminium is attacked by Cl− ions resulting in its disruption and formation of pitting corrosion. It is particularly important to determine the electrochemical properties of the produced welds and to evaluate the efect of welding parameters on these properties. The following paper presents a study on the corrosion properties of welds of dissimilar aluminium alloys, AA6082 and AA6060, produced for two diferent tool traverse speeds of 160 and 200 mm/min, with consideration of the size of crystallites and residual stresses in the samples, determined by Williamson-Hall analysis and micro-indentation tests. The results revealed that the size of the crystallites in the welds was larger compared to the base materials and the friction mstir welding process generated residual compressive stresses. Furthermore, the welds exhibited higher corrosion resistance compared to the parent materials. Scanning electron microscope observations indicated that the preferred locations of corrosion propagation for welds are the edges on the joint line formed by the combination of rotational and linear motion of the tool.

  • Cosmic-Time Quantum Mechanics and the Passage-of-Time Problem
    • Marek Czachor
    2023 Full text Universe

    A new dynamical paradigm merging quantum dynamics with cosmology is discussed.

  • Cost-Efficient Two-Level Modeling of Microwave Passives Using Feature-Based Surrogates and Domain Confinement
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    • Qi-Jun Zhang
    2023 Full text Electronics

    A variety of surrogate modelling techniques has been utilized in high-frequency design over the last two decades. Yet, the curse of dimensionality still poses a serious challenge in setting up re-liable design-ready surrogates of modern microwave components. The difficulty of the model-ing task is only aggravated by nonlinearity of circuit responses. Consequently, constructing a practically usable surrogate model, valid across extended ranges of material, geometry, and op-erational parameters, is far from easy. As a matter of fact, conventional modeling techniques are merely capable of building models for microwave structures featuring a relatively small num-ber of designable parameters within reduced ranges thereof. One of possible ways of mitigating these obstacles may be the employment of the recently proposed two-stage performance-driven modeling approach. Therein, the surrogate model domain is narrowed-down to the section of the space where the vectors of adequate quality are located, thereby permitting to significantly reduce the cost of acquiring the training data. Seeking even further cost reduction, this work in-troduces a novel modeling framework, which exploits problem-specific knowledge extracted from the circuit responses to achieve substantial cost-savings of training data acquisition. In our methodology, the modeling procedure targets response features instead of the complete re-sponses. The response features are the characteristic locations of the circuit response, such as relevant minima or maxima over selected frequency bands. The dependency of the coordinates of the said features on circuit dimensions is considerably less non-linear than it is observed for the complete characteristics, which enables sizable reduction of the data acquisition cost. Nu-merical validation of our procedure involving three microwave structures corroborates its re-markable efficiency, which allows for setting design-ready surrogates using only a handful of samples.

  • Crack Resistance of Asphalt Concrete Subjected to Environmental Factors
    • Cezary Szydłowski
    • Marcin Stienss
    2023 Full text NanoWorld Journal

    The paper presents an analysis of the influence of environmental factors on the cracking susceptibility of asphalt concrete resulting in a change in the durability of asphalt pavement. In order to assess the phenomenon, laboratory tests were carried out taking into account the destructive effects of moisture, freeze-thaw cycle and long-term ageing. The influence of both factors occurring simultaneously was also verified. Due to the different methods of assessing resistance to water and frost, the tests were carried out according to four variants of conditioning the samples: Polish Technical Requirements WT:2-2010 and WT:2-2014, AASTHO (American Association of State Highway and Transportation Officials) T 273, AASHTO TP 140 (MIST). Long-term aging was conducted according to AASHTO R 30 for 120 h and also in extended time to 216 h. Finally, ten variants of conditioning samples were tested. Asphalt concrete for wearing course was investigated. Parameters of mixtures with neat (50/70) and SBS-modified (45/80-55) binders were compared. The evaluation of changes in fracture toughness was carried out based on the results of testing SCB (Semicircular bending) specimens with a 10 mm notch depth at a temperature of +10 °C, at a loading rate of 1 mm/min. Fracture toughness, fracture energy and Flexibility Index were assessed. A group of 40 results for each of the mixtures was obtained, taking into account both the dispersion due to material heterogeneity (four samples for each of the conditioning variants) and variation in material properties caused by environmental factors (10 conditioning variants). The influence of water and frost action causes a decrease in fracture toughness and a reduction in fracture energy. Long-term ageing increases the stiffness of the mixture, thus increasing the fracture toughness. A significant increase in the brittleness of the material is observed, which reduces the deformation at fracture and thus the fracture energy. On the basis of the obtained results, it can be concluded that the destructive effect of environmental factors is clearly more visible in the case of a mixture with a neat binder. The comprehensive laboratory test results allowed for probabilistic analysis and reliability estimation related to the assessment of the durability of asphalt mixtures. It could be concluded that asphalt pavements made with the use of modified bitumen are characterized by significantly higher durability.

  • Credit default swaps and banks
    • Muhammad Mushafiq
    2023

    This chapter aims to explore the evolving role of credit default swaps (CDS) in managing and transferring default risk from the perspective of banks from a holistic perspective. This chapter examines credit default swaps (CDSs) as derivative financial instruments that transfer credit risk on debt securities. While CDSs offer benefits such as risk management and risk trading, they also introduce potential systemic risks, as evidenced by their role in the 2008 financial crisis. The collapse of American International Group (AIG) serves as a case study, highlighting the complex interactions between banks, CDSs, and the broader financial system. AIG’s exposure to mortgage-backed securities through CDSs led to significant losses and threatened the stability of the financial system.

  • Cross-Lingual Knowledge Distillation via Flow-Based Voice Conversion for Robust Polyglot Text-to-Speech
    • Dariusz Piotrowski
    • Renard Korzeniowski
    • Alessio Falai
    • Sebastian Cygert
    • Kamil Pokora
    • Georgi Tinchev
    • Ziyao Zhang
    • Kayoko Yanagisawa
    2023

    In this work, we introduce a framework for cross-lingual speech synthesis, which involves an upstream Voice Conversion (VC) model and a downstream Text-To-Speech (TTS) model. The proposed framework consists of 4 stages. In the first two stages, we use a VC model to convert utterances in the target locale to the voice of the target speaker. In the third stage, the converted data is combined with the linguistic features and durations from recordings in the target language, which are then used to train a single-speaker acoustic model. Finally, the last stage entails the training of a locale-independent vocoder. Our evaluations show that the proposed paradigm outperforms state-of-the-art approaches which are based on training a large multilingual TTS model. In addition, our experiments demonstrate the robustness of our approach with different model architectures, languages, speakers and amounts of data. Moreover, our solution is especially beneficial in low-resource settings.

  • Cross-Linking, Morphology, and Physico-Mechanical Properties of GTR/SBS Blends: Dicumyl Peroxide vs. Sulfur System
    • Agata Rodak
    • Agnieszka Susik
    • Daria Kowalkowska-Zedler
    • Łukasz Zedler
    • Krzysztof Formela
    2023 Full text Materials

    In this work, ground tire rubber and styrene–butadiene block copolymer (GTR/SBS) blends at the ratio of 50/50 wt%, with the application of four different SBS copolymer grades (linear and radial) and two types of cross-linking agent (a sulfur-based system and dicumyl peroxide), were prepared by melt compounding. The rheological and cross-linking behavior, physico-mechanical parameters (i.e., tensile properties, abrasion resistance, hardness, swelling degree, and density), thermal stability, and morphology of the prepared materials were characterized. The results showed that the selected SBS copolymers improved the processability of the GTR/SBS blends without any noticeable effects on their cross-linking behavior—which, in turn, was influenced by the type of cross-linking agent used. On the other hand, it was observed that the tensile strength, elongation at break, and abrasion resistance of the GTR/SBS blends cured with the sulfur system (6.1–8.4 MPa, 184–283%, and 235–303 mm3, respectively) were better than those cross-linked by dicumyl peroxide (4.0–7.8 MPa, 80–165%, and 351–414 mm3, respectively). Furthermore, it was found that the SBS copolymers improved the thermal stability of GTR, while the increasing viscosity of the used SBS copolymer also enhanced the interfacial adhesion between the GTR and SBS copolymers, as confirmed by microstructure evaluation.

  • Crystal facet effects in photocatalytic degradation of organic pollutants over anatase TiO2
    • Szymon Dudziak
    2023 Full text

    Presented work show detailed effect of the exposed crystal facets of anatase TiO2 on the photocatalytic degradation of organic pollutants. The most important existing information about the geometry and electronic properties of the low index anatase facets are summarised. During the performed works, anatase nanoparticles with the dominant exposition of either {0 0 1}, {1 0 0} or {1 0 1} crystal facets were prepared and their photocatalytic activity was tested. A significant effect of the exposed crystal facets was observed for the degradation and mineralisation of compounds, such as phenol, toluene, ibuprofen, carbamazepine and acetaminophen. Overall results have indicated significant effect of the exposed facet, with stoichiometric {1 0 1} being the most suitable for both degradation and mineralisation of all studied compounds, with the observed degradation rate constant being approximately 2-3 higher than other nanostructures. Furthermore, after combining with the BaFe12O19 ferrite, different effects of both electronic and magnetic interactions between both phases were observed, depending on the exposed TiO2 facets. Finally, doping of the obtained structures allowed to maximise activity of the {1 0 1} facets, simultaneously showing different effect of the same dopant, depending on the surface electronic structure of the material.

  • Crystal Facet Engineering of TiO2 from Theory to Application
    • Szymon Dudziak
    • Marta Kowalkińska
    • Anna Zielińska-Jurek
    2023 Full text

    Recently, the surface structure effect on photocatalytic activity has gathered increasing attention due to its reported influence on the charge carrier trapping and separation. Detailed control over the surface structure can be achieved by exposing the specific crystal facets. As a result, the photogenerated electrons and holes can be effectively separated between the different facets of semiconductor crystals. TiO2 is the most studied photocatalyst, with the particles exposing {0 0 1}, {1 0 0}, {1 0 1}, {1 1 0}, {1 1 1}, and {1 0 5} crystal facets. The performed studies have shown that the efficiency of the photocatalytic process strongly depends on the nature of the crystal facet exposed at the photocatalyst surface. In this regard, this chapter focuses on the comparison of possible surface-related parameters and photocatalytic activity of anatase, rutile, and brookite polymorphs with exposed different crystal facets. Particularly, computational data on their different possible surface structures are summarized, focusing on the geometry, energy, and possible reconstructions. This is followed by the general description of the hypothetical Wulff constructions and existing stabilization/synthesis strategies. Such an approach could help to further design, simulate, and optimize photocatalyst surface for efficient photoreduction and photooxidation processes.

  • Crystalline Silicon (c-Si)-Based Tunnel Oxide Passivated Contact (TOPCon) Solar Cells: A Review
    • Hayat Ullah
    • Stanisław Czapp
    • Seweryn Szultka
    • Hanan Tariq
    • Usama Bin Qasim
    • Hassan Imran
    2023 Full text ENERGIES

    Contact selectivity is a key parameter for enhancing and improving the power conversion efficiency (PCE) of crystalline silicon (c-Si)-based solar cells. Carrier selective contacts (CSC) are the key technology which has the potential to achieve a higher PCE for c-Si-based solar cells closer to their theoretical efficiency limit. A recent and state-of-the-art approach in this domain is the tunnel oxide passivated contact (TOPCon) approach, which is completely different from the existing classical heterojunction solar cells. The main and core element of this contact is the tunnel oxide, and its main role is to cut back the minority carrier recombination at the interface. A state-of-the-art n-type c-Si-based TOPCon solar cell featuring a passivated rear contact was experimentally analyzed, and the highest PCE record of ~25.7% was achieved. It has a high fill factor (FF) of ~83.3%. These reported results prove that the highest efficiency potential is that of the passivated full area rear contact structures and it is more efficient than that of the partial rear contact (PRC) structures. In this paper, a review is presented which considers the key characteristics of TOPCon solar cells, i.e., minority carrier recombination, contact resistance, and surface passivation. Additionally, practical challenges and key issues related to TOPCon solar cells are also highlighted. Finally, the focus turns to the characteristics of TOPCon solar cells, which offer an improved and better understanding of doping layers and tunnel oxide along with their mutual and combined effect on the overall performance of TOPCon solar cells.

  • Cu( II ) ions removal from wastewater using starch nanoparticles ( SNPs ): An Eco‐sustainable approach
    • Vikas S. Hakke
    • Vividha K. Landge
    • Shirish H. Sonawane
    • G. Uday B. Babu
    • Sivakumar Manickam
    • Grzegorz Boczkaj
    2023 Full text CANADIAN JOURNAL OF CHEMICAL ENGINEERING

    The complex structured starch particles were reduced to the nanoscale size range through hydrolysis utilizing low concentration acid assisted with ultrasound irradiation. The synthesized starch nanoparticles (SNPs) were characterized by TEM, FTIR, and XRD techniques. The synthesized SNPs possessed surface activated entities, as many cationic functional groups were confirmed through the FTIR spectrum. Also, these SNPs were effectively utilized to separate heavy Cu metal ions from the synthetic ion solution. The SNPs were characterized using FESEM, XPS and BET for the surface modification after the adsorption process. The weak electrostatic interaction between the SNP surface and Cu ion was confirmed from the XPS spectrum and energy dispersive X-ray spectroscopy. The maximum efficiency of Cu ions removal was about 93% at an optimal pH 5 and 25 mg/mL dosage. The adsorption equilibrium was obtained in 60 min. The nitrogen isotherm BET analysis of SNPs after adsorption shows a higher specific surface area of 18.552 m2/g, attributed to the interaction and presence of Cu ions on the SNP surface. The process feasibility was validated by the Langmuir isotherm model. The process exhibits pseudo-second-order adsorption kinetics and follows the Langmuir isotherm. The RL predicted by the Langmuir isotherm mechanism is 0.017, implying favorable adsorption. The process is reproducible and allows to separate heavy metal ions from the wastewater through bio-sorption effectively.

  • Cu-HKUST-1 and Hydroxyapatite–The Interface of Two Worlds toward the Design of Functional Materials Dedicated to Bone Tissue Regeneration
    • Marzena Fandzloch
    • Weronika Bodylska
    • Joanna Trzcińska-Wencel
    • Patrycja Golińska
    • Katarzyna Roszek
    • Joanna Wiśniewska
    • Michał Bartmański
    • Agnieszka Lewińska
    • Anna Jaromin
    2023 Full text ACS Biomaterials Science & Engineering

    A novel composite based on biocompatible hydroxyapatite (HA) nanoparticles and Cu-HKUST-1 (Cu-HKUST-1@HA) has been prepared following a layer-by-layer strategy. Cu-HKUST-1 was carefully selected from a group of four Cu-based metal−organic frameworks as the material with the most promising antimicrobial activity. The formation of a colloidal Cu- HKUST-1 layer on HA nanoparticles was confirmed by various techniques, e.g., infrared spectroscopy, powder X-ray diffraction, N2 sorption, transmission electron microscopy imaging, electron paramagnetic resonance, and X-ray absorption spectroscopy. Importantly, such a Cu-HKUST-1 layer significantly improved the nanomechanical properties of the composite, with Young’s modulus equal to that of human cortical bone (13.76 GPa). At the same time, Cu-HKUST-1@HA has maintained the negative zeta potential (−16.3 mV in pH 7.4) and revealed biocompatibility toward human dermal fibroblasts up to a concentration of 1000 μg/mL, without inducing ex vivo hemolysis. Chemical stability studies of the composite over 21 days in a buffer-simulated physiological fluid allowed a detailed understanding of the transformations that the Cu-HKUST-1@HA undergoes over time. Finally, it has been confirmed that the Cu-HKUST-1 layer provides antibacterial properties to HA, and the synergism reached in this way makes it promising for bone tissue regeneration.

  • CuO-decorated MOF derived ZnO polyhedral nanostructures for exceptional H2S gas detection
    • Shahid Hussain
    • Jesse Nii Okai Amu-Darko
    • Mingsong Wang
    • Asma A. Alothman
    • Mohamed Ouladsmane
    • Samar A. Aldossari
    • Muhammad Khan
    • Guanjun Qiao
    • Guiwu Liu
    2023 CHEMOSPHERE

    Considering that H2S is a hazardous gas that poses a significant risk to people's lives, research into H2S gas sensors has garnered a lot of interest. This work reports a CuO/ZnO multifaceted nanostructures(NS) created by heat treating Cu2+/ZIF-8 impregnation precursors, and their microstructure and gas sensing characteristics were examined using various characterization techniques (XRD, XPS, SEM, TEM, and BET). The as-prepared hollow CuO/ZnO multifunctional nanostructures had a high gas response value (425@50 ppm H2S gas), quick response and recovery times (57/191s @20 ppm), a low limit of detection ( 1.6@500 ppb H2S), good humidity resistance and highly selective towards H2S gas. The hollow CuO/ZnO multifaceted nanostructures possessed enhanced gas sensing capabilities which may be related to their porous hollow nanostructures, the manufactured p-CuO/n-ZnO heterojunctions, and the spillover effect between CuO and H2S.

  • Cyclic behavior of FeCoCrNiMn high entropy alloy coatings produced through cold spray
    • Pasquale Cavaliere
    • Angelo Perrone
    • Alessio Silvello
    • Aleksandra Laska
    • Gianni Blasi
    • Irene G. Cano
    • Behzad Sadeghi
    • S. Nagy
    2023 JOURNAL OF ALLOYS AND COMPOUNDS

    eCoCrNiMn high entropy alloy powders were employed to produce coatings on carbon steel through high pressure cold spray (at 1100 °C and 7 MPa in temperature and pressure respectively). X-ray diffraction of the sprayed material revealed a dense coating with the retention of the original crystallographic structure. Once splatted, particles revealed high flattening ratio with consequent excellent adhesion of the coating to the substrate. Residual stresses and hardness increased through the thickness of the coating. The cyclic behavior of the coatings was evaluated through bending tests. The cyclic bending tests were performed by linearly increase the maximum deformation at a fixed number of loading cycles. Other bending tests were conducted at fixed maximum stroke at the same deformation levels indicated for the previous test up to the coating fracture. For ach 100 cycles the test was stopped in order to observe the coating surface to gain the possibility of evaluating the aspect of the superficial fracture. The fracture surface of the coatings was observed through scanning electron microscopy in order to describe the cracking features related to the different loading conditions imposed to the coatings.

  • Cyfrowy HR. Organizacja w warunkach transformacji technologicznej
    • Małgorzata Sidor-Rządkowska
    • Łukasz Sienkiewicz
    2023

    Publikacja jest pierwszą na rynku pozycją opisującą kompleksowo zagadnienia związane z cyfryzacją HR. Autorzy szczegółowo omawiają poszczególne aspekty procesu wdrażania rozwiązań cyfrowych, a także podkreślają kluczową rolę, jaką dział HR odgrywa w kształtowaniu nowej cyfrowej kultury organizacyjnej w firmie. W monografii omówiono zagadnienia takie jak m.in.: * nowe role HR w procesie digitalizacji firmy, * cyfrowe zarządzanie danymi personalnymi, * analityka predykcyjna i algorytmy w HR, * wpływ kluczowych technologii na zmiany w obszarze pracy. Autorzy poruszają także etyczny aspekt transformacji cyfrowej, wskazując przykładowe dylematy związane z ochroną i wykorzystaniem danych osobowych, przejrzystością procesów czy dobrostanem pracowników.

  • Cykl obrazów: CZŁOWIEK WOBEC| uwspólnienie udział w ogólnopolskiej wystawie zbiorowej EMOTIONAL ECOLOGY / EKOLOGIA EMOCJONALNA. Ekologia, humanizm, etyka. Świadomość historii wzornictwa i nowe ścieżki rozwojowe jako element procesu. | cykl: ‘Design w procesie’
    • Agnieszka Kurkowska
    2023

    „Zależności pomiędzy organizmami i miejscem ich przebywania, są obszarem zainteresowania kreatorek i kreatorów. Czerpią oni impuls płynący z emocji własnych i innych organizmów. W efekcie synergii emocji, powstaje perspektywa przestrzeni naturalnej. Ekologia opiera się na systemie wymiany pomiędzy miejscem przebywania a kreatorami. Relacja ta zachodzi dokładnie pomiędzy jednostką a środowiskiem społecznym i naturalnym. Człowiek współstanowi o niesamowitej relacji emocjonalnej, powstającej w pewnym splocie istnienia organizmu ludzkiego i jego otoczenia. W ten sposób kreuje się wielo-organizm. Jego funkcje, sposoby zachowania, uwarunkowania kulturowe wynikają bezpośrednio z natury, z szacunku do otaczającego świata. Nowy sposób wymiany pomiędzy człowiekiem a środowiskiem proponują twórcy kierujący się tropem emocji. Stąd nie jesteśmy ludźmi sami przez się, ale poprzez istnienie (proces życiowy) w środowisku zewnętrznym, organizowanym przez emocje.

  • Cykl rzeźb pt. 'struktury biomorficzne'
    • Agnieszka Kurkowska
    2023

    Dotykam świata formą. Tworzę ją z marzeń i obrazów przyrody. Jestem architektem, co pozwala mi dotykać wzrokiem. Rysuję, rzeźbię, sytuuję gliniane obiekty i sprawdzam, czy miejsce je akceptuje. Poszukuję odczucia zgodności. Zgodność kierunkuje podejmowane próby. Wyobraźnia pyta o mieszkańców. Formy mogą mieścić domy. Schronienia bezpiecznie osadzone w kaszubskim krajobrazie. Brzmiące lasem, pachnące tradycją. Nie znam ich dalszych losów. Zawieszam myśli pomiędzy tym co wiem, a tym czego się spodziewam. Moje doświadczenia tworzą kształty. Spokój miejsca daje siłę do pracy. Utkane z marzeń, ułożone z doświadczeń, dotykające z nadzieją, formą zapożyczoną, przemyślaną i podarowaną miejscu. Najważniejsze jest dotknięcie, rozciągłe po nieregularności obiektu. Dotknięcie podłoża i powietrza. Tła. Uwolniony zapach i przeczucie. Ulotność, która nadaje sens. „Dotykanie jest zjawiskiem dwustronnym. To świat nas dotyka, gdy my go dotykamy” * Zarys i płaszczyzna styku. Definiują przebieg relacji. Oczekuję od nich potwierdzenia celu poszukiwań. Ten etap procesu niesie obawy niepowodzeń, ale i nadzieję adaptacji. Kto powiedział, że architekt nie może w ten sposób poszukiwać formuły dla domu spasowanego z miejscem? Mniej dosłownie. Bardziej delikatnie. Przyglądając się nieuchwytności i ciesząc słońcem dotykającym gliny z odciskiem mojej skóry. „Dzięki dotykowi nasza obecność objawia się nie w przestrzeni, tylko wobec innej, bliskiej rzeczywistości” * *cytaty: Brach-Czaina Jolanta 2022. Błony umysłu. Dowody na istnienie, Warszawa

  • Cylindrical orifice testing in laminar flow with the orifice diameter ratio β = 0.5
    • Anna Golijanek-Jędrzejczyk
    • Andrzej Mrowiec
    2023 Full text Scientific Reports

    The paper presents the results of an experimental study of a cylindrical orifice with the orifice diameter ratio β = 0.5 and the flow opening length‑to‑diameter ratio L/d = 1, with hydraulic oil flowing in the DN50 measuring channel. The measurements of the values characterising the oil flow were made in the laminar flow regime, for the Reynolds numbers ranging between Re = 100 to 950. Based on the experimental tests, standard flow characteristics were created for four kinematic viscosity values in the range of 13.4–33.3 cSt, for which the average value of the discharge coefficient C in the tested flow rate range of q v < 0.5 dm 3 /s was determined.

  • Cytokine IL6, but not IL-1β, TNF-α and NF-κB is increased in paediatric cancer patients
    • Anna Synakiewicz
    • Anna Stanisławska-Sachadyn
    • Anna Owczarzak
    • Małgorzata Skuza
    • Teresa Stachowicz-Stencel
    2023 Full text Acta Biochimica Polonica

    Cytokines are responsible for maintaining homeostasis as cell growth, differentiation, migration and apoptosis mediators. They play a pivotal role in immune responses to inflammatory reactions. In oncological diseases, the cross-talk between cells of the immunological system and cells of the tumour microenvironment is led by cytokines. Also, the overproduction of cytokines may change the tumour microenvironment and stimulate tumour development and growth. To test whether pro-inflammatory cytokines or associated with them transcription factor levels are changed in a group of 53 paediatric cancer patients, serum levels of IL-1β, IL-6, TNF-α and NF-κB were assessed and compared to measures in 25 healthy controls. Increased levels of IL-6 were found among patients in active oncological treatment (P=0.002) but not among patients whose treatment was completed. Our data suggest that IL6, but not IL-1β, TNF-α and NF-κB, is elevated as a result of the immune response in the microenvironment around the tumour and in blood cancers, among patients who were not infected at the time of blood collection. Thus, IL6 levels might serve as a potential biomarker of oncohematological diseases.

  • Czy chemia wszechświata różni się od chemii na planecie Ziemia?
    • Bartłomiej Cieślik
    2023

    Astronomowie, fizycy i chemicy od lat zadają sobie pytanie na ile nasza planeta jest wyjątkowa. Żyjemy na jednym z nielicznych ciał niebieskich, na którym występuje woda w stanie ciekłym. Na naszej planecie pojawiła się niezwykle szeroka gama prostych i wyjątkowo skomplikowanych związków organicznych. Warto jednak zadać pytanie czy faktycznie ziemia jest tak wyjątkowa pod kątem chemicznym, a jeśli tak to co na to wpływa. Współcześnie naukowcy wiedzą już o wszechświecie na tyle dużo, że można spróbować odpowiedź na to pytanie.

  • Czynniki kształtujące skuteczność outsourcingu w podmiotach leczniczych
    • Piotr Grudowski
    • Mateusz Muchlado
    2023

    Problem badawczy podjęty przez autorów tej książki można więc sformułować następująco: Jakie procesy podlegają outsourcingowi i jakie czynniki decydują o ich skuteczności w szpitalach w Polsce? W konsekwencji celem badawczym przyjętym w niniejszej pracy jest identyfikacja procesów zlecanych na zewnątrz w polskich szpitalach wraz z czynnikami warunkującymi ich skuteczność. Celem utylitarnym jest zaś opracowanie metody umożliwiającej kadrze zarządzającej polskimi szpitalami dobór dostawców oraz ocenę procesów poddanych outsourcingowi. Niniejsza monografia składa się z trzech głównych rozdziałów. W rozdziale 1 omówiono pojęcie outsourcingu oraz wykorzystanie go w zarządzaniu procesami. Opisano też czynniki sprawiające, że organizacje decydują się na zlecanie procesów na zewnątrz, jak również szanse i zagrożenia z tym związane. Przedstawiono charakterystykę podejścia procesowego, a także metody klasyfikacji procesów, których zastosowanie jest niezbędne przy wydzielaniu procesu na zewnątrz. Scharakteryzowano też najczęściej wykorzystywane w praktyce oraz sugerowane w literaturze przedmiotu metody oceny skuteczności procesów. W rozdziale 2 przedstawiono organizacje stanowiące podmiot badań oraz ich charakterystykę w świetle literatury. Zawarto tu również wnioski płynące z przeglądu literatury dotyczącej outsourcingu w podmiotach leczniczych w Polsce i za granicą, które odnoszą się do rodzaju procesów wydzielanych oraz motywów prowadzących do outsourcingu. Opisano uwarunkowania prawne i normatywne wpływające na wybór dostawcy outsourcingowego i ocenę skuteczności procesów poddanych outsourcingowi. W rozdziale 3 przedstawiono zastosowaną przez autorów metodykę badawczą. Zaprezentowano wybrane wyniki badań, które posłużyły do weryfikacji postawionych hipotez, a także do osiągnięcia celu utylitarnego, czyli opracowania metody oceny skuteczności procesów poddanych outsourcingowi. Metoda ta została omówiona w końcowej. części rozdziału. W podsumowaniu przedstawiono ujęte syntetycznie wyniki przeprowadzonych badań, wnioski i rekomendacje, w tym te związane z funkcjonowaniem placówek ochrony zdrowia w warunkach kryzysu i niepewności. Książka adresowana jest przede wszystkim do osób zajmujących się zarządzaniem w sektorze ochrony zdrowia, zarówno praktyków, jak i badaczy tej problematyki. Powinna się też spotkać z zainteresowaniem studentów kierunków związanych z zarządzaniem w usługach publicznych.

  • Data, Information, Knowledge, Wisdom Pyramid Concept Revisited in the Context of Deep Learning
    • Bożena Kostek
    2023

    In this paper, the data, information, knowledge, and wisdom (DIKW) pyramid is revisited in the context of deep learning applied to machine learningbased audio signal processing. A discussion on the DIKW schema is carried out, resulting in a proposal that may supplement the original concept. Parallels between DIWK pertaining to audio processing are presented based on examples of the case studies performed by the author and her collaborators. The studies shown refer to the challenge concerning the notion that classification performed by machine learning (ML) is/or should be better than human-based expertise. Conclusions are also delivered.

  • Data-driven, probabilistic model for attainable speed for ships approaching Gdańsk harbour
    • Jakub Montewka
    • Marcin Życzkowski
    • Filip Zarzycki
    2023

    The growing demand for maritime transportation leads to increased traffic in ports. From this arises the need to observe the consequences of the specific speed ships reach when approaching seaports. However, usually the analyzed cases refer only to the statistical evaluation of the studied phenomenon or to the empirical modelling, ignoring the mutual influence of variables such as ship type, length or weather conditions. In this paper, a different approach to the issue is proposed, which summarizes the most important factors and leads to a probabilistic speed model for manoeuvring ships in the port of Gdańsk. For this purpose, data from the Automatic Identification System were used. This resulted in a dataset with almost 2.5k traffic scenarios. To obtain results from the dataset, three different machine learning algorithms based on Bayesian networks were then applied. The developed models can be used to predict the speed as a function of the given parameters as well as to determine the values of individual parameters for a given speed. In addition, the use of the constructed models allowed the analysis of the strength of mutual influences for two connected nodes or the sensitivity of changes for individual variables. The discussion also raised questions about validation of the algorithms and measures to improve accuracy. The average predictive accuracy of the models of about 75% (depending on the learning algorithm used) achieved at this stage is promising, but further work is expected that can increase the predictive power of the models.

  • Data-Driven Surrogate-Assisted Optimization of Metamaterial-Based Filtenna Using Deep Learning
    • Peyman Mahouti
    • Aysu Belen
    • Ozlem Tari
    • Mehmet Belen
    • Serdal Karahan
    • Sławomir Kozieł
    2023 Full text Electronics

    In this work, a computationally efficient method based on data driven surrogate models is pro-posed for the design optimization procedure of a Frequency Selective Surface (FSS)-based filtering antenna (Filtenna). A Filtenna acts as a as module that simultaneously pre-filters unwanted sig-nals, and enhances the desired signals at the operating frequency. However, due to a typically large number of design variables of FSS unit elements, and their complex interrelations affecting the scattering response, FSS optimization is a challenging task. Herein, a deep-learning-based al-gorithm, Modified-Multi-Layer-Perceptron (M2LP), is developed to render an accurate behavioral model of the unit cell. Subsequently, the M2LP model is applied to optimize FSS elements being parts of the Filtenna under design. The exemplary device operates at 5 GHz to 7 GHz band. The numerical results demonstrate that the presented approach allows for almost 90% reduction of the computational cost of the optimization process as compared to direct EM-driven design. At the same time, physical measurements of the fabricated Filtenna prototype corroborate the relevance of the proposed methodology. One of the important advantages of our technique is that the unit cell model can be re-used to design FSS and Filtenna operating a various operating bands without incurring any extra computational expenses.

  • Dataset Related Experimental Investigation of Chess Position Evaluation Using a Deep Neural Network
    • Dawid Wieczerzak
    • Paweł Czarnul
    2023 Full text

    The idea of training Articial Neural Networks to evaluate chess positions has been widely explored in the last ten years. In this paper we investigated dataset impact on chess position evaluation. We created two datasets with over 1.6 million unique chess positions each. In one of those we also included randomly generated positions resulting from consideration of potentially unpredictable chess moves. Each position was evaluated by the Stockfish engine. Afterwards, we created a multi class evaluation model using Multilayer Perceptron. Solution to the evaluation problem was tested with three different data labeling methods and three different board representations. We show that the accuracy for the model trained for the dataset without randomly generated positions is higher than for the model with such positions, for all data representations and 3, 5 and 11 evaluation classes.

  • Debonding of coin-shaped osseointegrated implants: Coupling of experimental and numerical approaches
    • Yoann Hériveaux
    • Sophie Le Cann
    • Katharina Immel
    • Elsa Vennat
    • Vu-Hieu Nguyen
    • Vladimir Brailovski
    • Patrick Karasinski
    • Roger Sauer
    • Guillaume Haiat
    2023 Full text Journal of the Mechanical Behavior of Biomedical Materials

    While cementless implants are now widely used clinically, implant debonding still occur and is difficult to anticipate. Assessing the biomechanical strength of the bone–implant interface can help improving the understanding of osseointegration phenomena and thus preventing surgical failures. A dedicated and standardized implant model was considered. The samples were tested using a mode III cleavage device to assess the mechanical strength of the bone-implant interface by combining experimental and numerical approaches. Four rough (Sa = 24.5 μm) osseointegrated coin-shaped implants were left in sheep cortical bone during 15 weeks of healing time. Each sample was experimentally rotated at 0.03◦/sec until complete rupture of the interface. The maximum values of the torque were comprised between 0.48 and 0.72 Nm, while a significant increase of the normal force from 7-12 N to 31–43 N was observed during the bone-implant interface debonding, suggesting the generation of bone debris at the bone-implant interface. The experimental results were compared to an isogeometric finite element model describing the adhesion and debonding phenomena through a modified Coulomb’s law, based on a varying friction coefficient to represent the transition from an unbroken to a broken bone-implant interface. A good agreement was found between numerical and experimental torques, with numerical friction coefficients decreasing from 8.93 to 1.23 during the bone-implant interface rupture, which constitutes a validation of this model to simulate the debonding of an osseointegrated bone-implant interface subjected to torsion.