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  • Fast EM-Driven Parameter Tuning of Microwave Circuits with Sparse Sensitivity Updates via Principal Directions
    • Anna Pietrenko-Dąbrowska
    • Mateusz Kozieł
    2022 KNOWLEDGE-BASED SYSTEMS

    Numerical optimization has become more important than ever in the design of microwave components and systems, primarily as a consequence of increasing performance demands and growing complexity of the circuits. As the parameter tuning is more and more often executed using full-wave electromagnetic (EM) models, the CPU cost of the overall process tends to be excessive even for local optimization. Some ways of alleviating these issues exist, yet, they are limited either by their accessibility or applicability range. This work presents a novel algorithmic approach to accelerated gradient-based parameter tuning of microwave components with numerical derivatives. In our methodology, computational savings are achieved by exploiting the problem-specific knowledge, specifically, by restricting the gradient updates to an orthonormal basis of essential directions corresponding to the maximum variability of the circuit responses within the frequency bands of interest. The said directions are selected through an automated decision-making process involving the analysis of the circuit response variability. Our approach is demonstrated using two multi-parameter microwave devices. Comprehensive comparison with the benchmark methods, including the standard trust-region algorithm and the three accelerated versions, indicate savings of up to fifty percent associated only with minor reduction of the design quality.

  • Fast Real-Time RDFT- and GDFT-Based Direct Fault Diagnosis of Induction Motor Drive
    • Piotr Kołodziejek
    • Daniel Wachowiak
    2022 Pełny tekst ENERGIES

    This paper presents the theoretical analysis and experimental verification of a direct fault harmonic identification approach in a converter-fed electric drive for automated diagnosis purposes. On the basis of the analytical model of the proposed real-time direct fault diagnosis, the fault-related harmonic component is calculated using recursive DFT (RDFT) and Goertzel DFT (GDFT), applied instead of the full spectrum calculations required in the most popular FFT algorithm. The simulation model of an inverter sensorlessly controlled induction motor drive is linked with the induction machine rotor fault model for testing the sensitivity of the GDFT- and RDFT-based fault diagnosis to state variable estimation errors. According to the presented simulation results, the accuracy of the direct identification of a fault-related harmonic is sensitive to the quality of fault harmonic frequency estimation. The sensitivity analysis with respect to RDFT and GDFT algorithms is included. Based on the experimental setup with a sensorlessly controlled induction motor drive with the investigated rotor fault, fault diagnosis algorithms were implemented in the microprocessor by integration with the control system in one microcontroller and experimentally verified. The RDFT and GDFT approach has shown accurate and fast direct automated fault identification at a significantly decreased number of arithmetical operations in the microcontroller, which is convenient for the frequency-domain fault diagnosis in electric drives and supports fault-tolerant control system implementation.

  • Fast-SEC coupled to ICP-MS for selected metal determination and its stability over time in polish wine
    • Magdalena Fabjanowicz
    • Justyna Płotka-Wasylka
    2022 Pełny tekst MONATSHEFTE FUR CHEMIE

    Metal ions contribute to the wine browning (as reaction catalysts), turbidity (in complexes), and astringency (due to inter- action with tannins). Being aware that bioavailability and metabolism of metal ions in the human body are strictly related with their concentration and the form they occur it is important to monitor not only the total content of metals but also their speciation. Thus, we can obtain more information about their potential toxicity to human health. Present research shows the application of fast size exclusion chromatography (Fast-SEC) coupled to ICP-MS for the evaluation of the distribution of elements in different sized complexes in Polish wine. The study was focused on the selected ten elements (Al, B, Ba, Cu, Fe, Mn, Ni, Pb, Sr, Zn). Additional information of this work was the evaluation of the metal complex stability over time. Based on the obtained results, it can be seen that metal complexes present in the studied wine samples are stable even 10 months after the wine bottle opening.

  • Fatigue Bending of V-Notched Cold-Sprayed FeCoCrNiMn Coatings
    • Pasquale Cavaliere
    • Angelo Perrone
    • Alessio Silvello
    • Aleksandra Laska
    • Gianni Blasi
    • Irene G. Cano
    2022 Pełny tekst Metals

    Cold-spray coatings were produced by FeCoCrNiMn high-entropy alloy powders deposited on carbon steel substrate. The coatings were realized at intermediate temperature and high pressure (at 1100 °C and 7 MPa). The coating microstructure was characterized by scanning electron microscopy and X-ray diffraction, revealing a very dense deposition and high flattening ratio of the splatted particles. This had a large influence on the strong adhesion of the mcoating to the substrate. The hardness and residual stress profiles were measured through nanoindentation and X-ray diffraction from the peak broadening measured layer by layer. The cyclic behavior of the coatings was evaluated through three-point bending tests performed on V-notched samples coated via cold spray. Cyclic tests were performed at different maximum strokes from 0.3 to 3.6 mm in order to monitor the crack initiation and propagation during bending tests. The fracture surface aspect was analyzed by scanning electron microscopy in order to reveal the fracture mechanisms in different deformation conditions.

  • Fatigue fracture morphology of AISI H13 steel obtained by additive manufacturing
    • Wojciech Macek
    • Rui F. Martins
    • Ricardo Branco
    • Zbigniew Marciniak
    • Mirosław Szala
    • Sebastian Wroński
    2022 Pełny tekst INTERNATIONAL JOURNAL OF FRACTURE

    The paper focuses on researching the effect of fatigue loading on metallic structure, lifetime, and fracture surface topographies in AISI H13 steel specimens obtained by selective laser melting (SLM). The topography of the fracture surfaces was measured over their entire area, according to the entire total area method, with an optical three-dimensional surface measurement system. The fatigue results of the SLM 3D printed steel specimens were compared with those reported for conventionally manufactured 13H steel. The investigation also considers the roughness of the specimens’ side surface. Moreover, the fractographic evaluation conducted using scanning electron microscopy confirms that the predominant fracture mechanism is transgranular fracture. Microtomography done after mechanical loading also showed the influence of the stress level on the porosity distribution. Both fractographic and Micro-CT investigations confirm that higher stresses result in coarser and much more uniform porosity observed in fractured samples. These comprehensive quantitative and qualitative fracture analyses are beneficial to predict the failure conditions of SLM steel parts, especially in the case of fatigue damage. From the quantitative analysis of the H13 SLM-manufactured fracture surface topography, it was possible to conclude that the larger the loadings acting on the specimen, the rougher the fracture surface because the ductile fracture mode dominates. It has also been proven that the porosity degree changes along the length of the sample for the most stressed specimens.

  • Fatigue fracture surface metrology of thin-walled tubular austenitic steel specimens after asynchronous loadings
    • Wojciech Macek
    • Łukasz Pejkowski
    • Ricardo Branco
    • Reza Masoudi Nejad
    • Krzysztof Żak
    2022 Pełny tekst ENGINEERING FAILURE ANALYSIS

    This paper aims to study the effect of asynchronous axial-torsional strain-controlled loading histories on fracture surface behavior of thin-walled tubular X5CrNi18-10 (304/304L) austenitic steel specimens. Tests under pure axial loading and pure torsional loading are also conducted to better segregate the effect of multiaxiality. The fractures surface topographies were examined through the profiles over the entire surface with the support of an optical measurement system. Then, features of the post-failure fractures were related to the loading conditions and the fatigue life. The outcomes indicate that the multiaxial loading path significantly affects the surface topography. Overall, fracture surface parameters increase for higher fatigue lives. Based on the dialectic relationship, a fatigue damage model able to estimate the fatigue lifetime under asynchronous axial-torsional loading histories has been successfully developed. The fracture surface topology parameters collected from both sides of the same specimen lead to comparable results which reinforces the applicability of the proposed approach.

  • Fatigue life improvement using low transformation temperature weld material with measurement of residual stress
    • Jordan Franks
    • Greg Wheatley
    • Pedram Zamani
    • Reza Masoudi Nejad
    • Wojciech Macek
    • Ricardo Branco
    • Farzaneh Samadi
    2022 Pełny tekst INTERNATIONAL JOURNAL OF FATIGUE

    Welding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial loading considering two types of LTT materials. The results show that the crack propagation of all samples was similar in cycles although both LTT materials extended the crack initiation, and, therefore, the overall life of the part. It was found that both LTT materials reduced the residual tensile stresses, increased the residual compressive stresses, leading to increase in fatigue life about 30%.

  • Fatigue of titanium alloy Ti6Al4V with diamond structure obtained by Laser Power Bed Fusion method
    • Anna Falkowska
    • Andrzej Seweryn
    2022 Pełny tekst INTERNATIONAL JOURNAL OF FATIGUE

    This paper presents the results of fatigue tests conducted on Ti6Al4V titanium alloy with diamond structure obtained by the Laser Power Bed Fusion method. Samples used in tests were printed with porosities: 81%, 73%, 50%, 34% and near-zero porosity. Samples were subjected to cyclic tests with a constant stress amplitude. The number of cycles until sample failure was registered. Obtained fatigue test results made it possible to determine simple, semi-empirical dependencies making it possible to forecast the fatigue life of Ti6Al4V titanium alloy with diamond structure obtained by the Laser Power Bed Fusion method under conditions of uniaxial, cyclically variable loads. The experimental results revealed that the initiation of the macro-crack occurred already with a small number of cycles. This was caused by the presence of two types of notches: technological micro-notches between particles of melted powder and notches related to the shape of the diamond structure itself. Microscopic observations of the fatigue fractures of samples were carried out, both on those subjected to low-cycle tests and those subjected to high-cycle tests. This made it possible to identify crack initiation and damage accumulation mechanisms as well as to propose numerical dependencies for samples of the tested structure. For this purpose, it is necessary to determine only the tensile strength of the given metamaterial and the fatigue characteristic for the given porosity.

  • Fault-tolerant performance of the novel five-phase doubly-fed induction generator
    • Roland Ryndzionek
    • Krzysztof Blecharz
    • Filip Kutt
    • Michał Michna
    • Grzegorz Kostro
    2022 Pełny tekst IEEE Access

    The article presents the concept of a new design of a multi-phase doubly-fed induction generator (DFIG). The innovative design approach uses a five-phase power supply from the rotor side of the generator with a three-phase classic stator power supply. Modern three-phase doubly-fed induction generators are the dominant choice for Wind Energy Conversion Systems (WECS). Solutions of this type are sensitive to the loss of at least one phase of the power supply from the rotor side due to the failure of the rotor side inverter. The proposed design solution in the form of a multi-phase power supply in the rotor circuit aims to extend the range of possible failure-free operation of the generator system, thus reducing system downtime due to the failure of power electronic systems. The correctness of the adopted conceptual assumptions was confirmed by the results of laboratory tests. The main contribution is to prove that using five-phase rotor winding improves the overall reliability of the proposed electrical energy generation system significantly.

  • Fe3–xInSnxO6 (x = 0, 0.25, or 0.5): A Family of Corundum Derivatives with Sn-Induced Polarization and Above Room Temperature Antiferromagnetic Ordering
    • Corey E. Frank
    • Emma E. McCabe
    • Fabio Orlandi
    • Pascal Manuel
    • Xiaoyan Tan
    • Zheng Deng
    • Changqing Jin
    • Mark Croft
    • Thomas Emge
    • Shukai Yu
    • Huaiyu Wang
    • Venkatraman Gopalan
    • Saul Lapidus
    • MeiXia Wu
    • Man-Rong Li
    • Juliane Gross
    • Paul Burger
    • Aleksandra Mielewczyk-Gryń
    • Tomasz Klimczuk
    • Weiwei Xie
    • David Walker
    • Martha Greenblatt
    2022 CHEMISTRY OF MATERIALS

    Three new double corundum derivative compounds, Fe3−xInSnxO6 (x = 0. 0.25, or 0.5), were synthesized at high pressure and temperature (6 GPa and 1400− 1450 °C). All of the compounds order antiferromagnetically well above room temperature (TN = 608, 532, and 432 K for x = 0, 0.25, and 0.5, respectively). The x = 0 phase crystallizes as centrosymmetric R3̅c, but the inclusion of closed-shell d10 Sn4+ induces x = 0.25 and 0.5 to crystallize as noncentrosymmetric R3c. Microprobe measurements indicate that for x = 0.25 and 0.5, the substitution of Sn4+ is not offset by vacancies, which implies the presence of Fe2+, as corroborated by X-ray absorption near-edge spectroscopy and single-crystal X-ray structure refinements. Neutron powder diffraction experiments on x = 0.5 indicate that these compounds are canted A-type antiferromagnets that, like Fe2O3 and InFeO3, consist of ferromagnetic layers that stack antiferromagnetically with a single magnetic transition. Weak ferromagnetic interactions persist to very high temperatures. Temperature-dependent second harmonic generation (SHG) measurements on x = 0.25 and 0.5 show a SHG response with ferroelectric-like hysteretic maxima that correspond with the respective magnetic transitions, which suggest coupling of the magnetic and polarization order. These new compounds provide more information about fine-tuning the electronic, magnetic, and structural properties of corundum-derived mutlferroics in the search for tunable high-temperature magnetoelectric materials.

  • Feature extraction in detection and recognition of graphical objects
    • Jerzy Dembski
    2022

    Detection and recognition of graphic objects in images are of great and growing importance in many areas, such as medical and industrial diagnostics, control systems in automation and robotics, or various types of security systems, including biometric security systems related to the recognition of the face or iris of the eye. In addition, there are all systems that facilitate the personal life of the blind people, visually impaired or people in full health, but who need devices to support them in the increasingly complex modern world, such as home monitoring systems or driving assistance systems.

  • Feature Weighted Attention-Bidirectional Long Short Term Memory Model for Change Detection in Remote Sensing Images
    • Raj Kumar Patra
    • Sujata N. Patil
    • Przemysław Falkowski-Gilski
    • Zbigniew Łubniewski
    • Rachana Poongodan
    2022 Pełny tekst Remote Sensing

    In remote sensing images, change detection (CD) is required in many applications, such as: resource management, urban expansion research, land management, and disaster assessment. Various deep learning-based methods were applied to satellite image analysis for change detection, yet many of them have limitations, including the overfitting problem. This research proposes the Feature Weighted Attention (FWA) in Bidirectional Long Short-Term Memory (BiLSTM) method to reduce the overfitting problem and increase the performance of classification in change detection applications. Additionally, data usage and accuracy in remote sensing activities, particularly CD, can be significantly improved by a large number of training models based on BiLSTM. Normalization techniques are applied to input images in order to enhance the quality and reduce the difference in pixel value. The AlexNet and VGG16 models were used to extract useful features from the normalized images. The extracted features were then applied to the FWA-BiLSTM model, to give more weight to the unique features and increase the efficiency of classification. The attention layer selects the unique features that help to distinguish the changes in the remote sensing images. From the experimental results, it was clearly shown that the proposed FWA-BiLSTM model achieved better performance in terms of precision (93.43%), recall (93.16%), and overall accuracy (99.26%), when compared with the existing Difference-enhancement Dense-attention Convolutional Neural Network (DDCNN) model.

  • Featured based CAVE software factory
    • Jacek Lebiedź
    • Bogdan Wiszniewski
    2022 Pełny tekst

    In the paper we convey the lessons learned along the path we have gone through several years since establishing a room-sized CAVE installation at our university, from craft manufacturing and ad-hoc software reuse of VR software products to the robust feature driven software product line (SPL) implementing the Product Line Engineering (PLE) factory paradigm. With that we can serve all our departments and other entities from the region by rapidly instantiating different VR products based on a standard set of core assets and driven by a set of common features of VR applications destined to be deployed in the same target CAVE system – with the minimal budget and time to market requirements. A comprehensive survey of the most representative CAVE applications created in Gdansk Tech Immersive 3D Visualization Lab (I3DVL) according to PLE paradigm presented in the paper provides evidence supporting this claim.

  • Features of irregularity in examples of Polish multi-family architecture constructed in 2011–2021 and nominated for the Mies van der Rohe award
    • Michał Malewczyk
    • Piotr Czyż
    2022 Pełny tekst Czasopismo Techniczne

    This article is devoted to the analysis of contemporary Polish multi-family architecture in the context of aesthetic irregularity. The research was limited to constructions from 2011–2021 and nominated for the Mies van der Rohe award as the objects with the greatest potential impact on shaping further trends. In their research, the authors focused on searching for the features of irregularities, which, in their opinion, have become a distinguishing feature of contemporary architectural aesthetics. The analyses in this study refer to three planes of the aesthetic dimension of architecture, namely the form, facade composition and material.

  • Featuring Semitransparent p–i–n Perovskite Solar Cells for High-Efficiency Four-Terminal/Silicon Tandem Solar Cells
    • Pei-Huan Lee
    • Ting-Tzu Wu
    • Chia-Feng Li
    • Damian Głowienka
    • Yu-Xuan Huang
    • Shih-Han Huang
    • Yu-Ching Huang
    • Wei-Fang Su
    2022 Pełny tekst Solar RRL

    Two issues need to be resolved when fabricating p–i–n semitransparent perovskite solar cells (ST-PVSCs) for four-terminal (4 T) perovskite/silicon tandem solar cells: 1) damage to the underlying absorber (MAPbI3), electron transporting layer ([6,6]-phenyl-C61-butyric acid methyl ester, PCBM), and work function (WF) modifier (polyethylenimine, PEI), resulting from the harsh sputtering conditions for the transparent electrodes (TEs) and 2) low average near-infrared transmittance (ANT) of TEs. Herein, a unique SnO2 layer to protect the MAPbI3 and PCBM layers is developed and functions as a WF modifier for a new TE (cerium-doped indium oxide, ICO), which exhibits an excellent ANT of 86.7% in the range of 800−1200 nm. Moreover, a MAPbI3-based p–i–n ST-PVSC is prepared, achieving an excellent power conversion efficiency (PCE) of 17.23%. When it is placed over the Si solar cell, a 4 T tandem solar cell with a PCE of 26.14% is obtained.

  • FEM and experimental investigations of concrete temperature field in the massive stemwall of the bridge abutment
    • Aleksandra Kuryłowicz-Cudowska
    • Krzysztof Wilde
    2022 Pełny tekst CONSTRUCTION AND BUILDING MATERIALS

    The paper deals with the prediction of early-age concrete temperature of cast-in-place stemwall of the bridge abutment. The considered object is an arch bridge located in Gda´nsk. In the case of massive structures, it is particularly important to not exceed the temperature difference between the core and the concrete surface. Too high temperature gradient generates an increase in thermal stresses, what could be the reason of exceeding the tensile strength and as a consequence cracking occurrence. Therefore, the numerical simulations of concrete hardening were conducted using own codes of finite difference and finite elements method. Based on numerical results the project of monitoring system was developed. The concrete temperature of stemwall was registered during 12 days by using fifteen 1-wire digital sensors. The recorded thermal data are highly consistent with FE results, which confirms the accuracy of the finite element model. The conducted calculations and in-situ measurements allowed to determine guidelines for proper curing of massive abutment’s wall.

  • Femtosecond Er-doped fiber laser source tunable from 872 to 1075 nm for two-photon vision studies in humans
    • Dorota Stachowiak
    • Marcin Marzejon
    • Jakub Bogusławski
    • Zbigniew Łaszczych
    • Katarzyna Komar
    • Maciej Wojtkowski
    • Grzegorz Soboń
    2022 Pełny tekst Biomedical Optics Express

    We report the development of a widely-tunable femtosecond fiber laser system and its application for two-photon vision studies. The source is based on an Er-doped fiber laser with spectral shift up to 2150 nm, followed by a second harmonic generation module to generate a frequency-doubled beam tunable from 872 to 1075 nm. The source delivers sub-230 fs pulses with nearly-constant duration over the entire tuning range, with output powers between 0.68–1.24 mW, which corresponds to a pulse energy of 13.2–24.1 pJ. Such pulse energy is sufficient for employing a system for measurements of two-photon scotopic spectral sensitivity of two-photon vision in humans. The laser parameters allow for very efficient and safe two-photon stimulation of the human visual system, as proved by a good separation between one- and two-photon thresholds for wavelengths below 950 nm, which we have confirmed for 3 healthy subjects.

  • Ferromagnetism in Pr-rich binary Pr7Ru3 intermetallic compound
    • Szymon Królak
    • Hanna Świątek
    • Karolina Górnicka
    • Michał Winiarski
    • Weiwei Xie
    • Robert J. Cava
    • Tomasz Klimczuk
    2022 Pełny tekst JOURNAL OF ALLOYS AND COMPOUNDS

    We present the synthesis and experimental characterization of the binary intermetallic compound Pr7Ru3. The polycrystalline sample was prepared by arc melting pure Pr and Ru, followed by homogenization at 500 °C and 600 °C for 48 and 89 h, respectively. Powder x-ray diffraction confirms that Pr7Ru3 crystallizes in an orthorhombic crystal structure (Pnma, space group no. 62) with the lattice parameters: a = 7.3606(7) Å, b = 23.120(1) Å and c = 6.5959(5) Å. Magnetization, resistivity, and heat capacity measurements reveal a ferromagnetic transition in Pr7Ru3 with the Curie temperature TC ∼ 24.5 K. The bulk transition is confirmed by a large λ-shape anomaly observed in the specific heat measurement. The magnetic susceptibility above the transition obeys the modified Curie-Weiss law with a positive Curie-Weiss temperature ϴCW = 30(1) K and an effective magnetic moment of 3.39(1) μB/Pr. Resistivity data for Pr7Ru3 reveals metallic-like behavior with a clear anomaly at the transition temperature which is smeared by an applied magnetic field. We also synthesized high-quality nonmagnetic analog La7Ru3 for which superconducting transition is observed with Tc = 1.95 K, in agreement with the literature.

  • Field Evaluation of High Modulus Asphalt Concrete Resistance to Low-Temperature Cracking
    • Marek Pszczoła
    • Dawid Ryś
    • Mariusz Jaczewski
    2022 Pełny tekst Materials

    High-modulus asphalt concrete has numerous advantages in comparison to conventional asphalt concrete, including increased resistance to permanent deformations and increased pavement fatigue life. However, previous studies have shown that the construction of road pavements with High Modulus Asphalt Concrete (HMAC) may significantly increase the risk of low-temperature cracking. Those observations were the motivation for the research presented in this paper. Four test sections with HMAC used in base and binder courses were evaluated in the study. Field investigations of the number of low-temperature cracks were performed over several years. It was established that the number of new low-temperature cracks is susceptible to many random factors, and the statistical term “reversion to the mean” should be considered. A new factor named Increase in Cracking Index was developed to analyze the resistance of pavement to low-temperature cracking. For all the considered field sections, samples were cut from each asphalt layer, and Thermal Stress Restrained Specimen Tests were performed in the laboratory. Correlations of temperature at failure and cryogenic stresses with the cracking intensity observed in the field were analyzed. The paper provides practical suggestions for pavement designers. When the use of high modulus asphalt concrete is planned for binder course and asphalt base, which may result in lower resistance to low-temperature cracking of pavement than in the case of conventional asphalt concrete, it is advisable to apply a wearing course with improved resistance to low-temperature cracking. Such an approach may compensate for the adverse effects of usage of high modulus asphalt concrete.

  • Finite-window RLS algorithms
    • Lu Shen
    • Yuriy Zakharov
    • Maciej Niedźwiecki
    • Artur Gańcza
    2022 Pełny tekst SIGNAL PROCESSING

    Two recursive least-squares (RLS) adaptive filtering algorithms are most often used in practice, the exponential and sliding (rectangular) window RLS algorithms. This popularity is mainly due to existence of low-complexity versions of these algorithms. However, these two windows are not always the best choice for identification of fast time-varying systems, when the identification performance is most important. In this paper, we show how RLS algorithms with arbitrary finite-length windows can be implemented at a complexity comparable to that of exponential and sliding window RLS algorithms. Then, as an example, we show an improvement in the performance when using the proposed finite-window RLS algorithm with the Hanning window for identification of fast time-varying systems.

  • Fire Protection and Materials Flammability Control by Artificial Intelligence
    • Henri Vahabi
    • Mohammad Naser Eldine
    • Mohammad Saeb
    2022 FIRE TECHNOLOGY

    Fire safety has become a major challenge of materials developers because of the massive production of organic materials, often combustibles, and their use for different purposes. In this sense, fire safety is critically considered in the development of engineering materials [1, 2]. The multiplicity of parameters contributing to the development of formulation of flame-retardant materials from one side and the sustainability concerns from the other side make the innovations cumbersome. Typically, there are variety of flame-retardant materials that are different in terms of the type, the amount, and the size, along with processing (e.g., extrusion, and additive manufacturing), and practical (e.g., ultimate price, recyclability, and life cycle) parameters that should be optimized to reach a desired product. On a parallel front, the instructions, standards, and safety requirements bring about further difficulties and limitations with materials design and fire protection. For instance, Scientific Committee on Consumer Safety (SCCS) claasifies materials as non-food products and risky materials as well as consumer services, to highlight health considerations. Correspondingly, fire suppression, fire fighting, fire extinguishing or other terms are defined, but controlling all parameters contributing to consumer safety and customer services requires identification and integration of materials and safety factors into an intelligent system capable of searching, ranking and classifying them in a very disciplined yet quick manner for emergency needs. The performance of a material under fire, both fire reaction and fire resistance, significantly depends on the shape and the geometry of structures, more specifically on the fire dynamics during a defined fire situation along with the material, ventilated, and under-ventilated situations. The selection of testing methodology, would also affect the success of strategies used for fire protection. These all would necessitate a bewildering of scenarios to be identified, classified, and examined by researchers working in the field, which wastes a great deal of time, investment, and practice.

  • FIRE RISK ASSESSMENT IN INDUSTRIAL PREMISES
    • Mariusz Jaczewski
    • Marek Pszczoła
    • Maciej Sawicki
    2022

    Chapter presents different aspects of fire risk assessment in industrial sites

  • Flame-Retardant Polymer Materials Developed by Reactive Extrusion: Present Status and Future Perspectives
    • Henri Vahabi
    • Fouad Laoutid
    • Krzysztof Formela
    • Mohammad Saeb
    • Philippe Dubois
    2022 Polymer Reviews

    The development of flame retardant polymer materials has two roots, one in materials design, and the other in materials processing. Over recent decades, different types and classes of flame retardant polymer materials have been commercialized to meet safety requirements in the construction, automotive, and coatings industries. In the vast majority of cases, the design and fabrication of new materials presenting low fire hazards could be obtained through the incorporation of one, two or more flame retardants with similar or different natures into polymers. Nevertheless, the presence of these new phases, often used at high loading levels, usually impact the polymer’s other functional properties, such as mechanical, aging and transparency. These limitations could be partially or totally overcome using reactive extrusion, which is a promising process for developing new polymers or modifying the chemical structure of existing ones. Amongst other possibilities, reactive extrusion can be used for enhancing the fire behavior of existing polymers or for the synthesis of new ones presenting inherent flame retardant properties. In recent years, several new flame retardant polymers have been developed by reactive extrusion, but these developments have not been systematically described with regard to their technical circumstances, properties, and commercial potential. This short review attempts to overview and classify the available reports on the development of flame-retardant polymeric materials through reactive extrusion processes.

  • Flexomagneticity in buckled shear deformable hard-magnetic soft structures
    • Mohammad Malikan
    • Victor Eremeev
    2022 Pełny tekst CONTINUUM MECHANICS AND THERMODYNAMICS

    This research work performs the first time exploring and addressing the flexomagnetic property in a shear deformable piezomagnetic structure. The strain gradient reveals flexomagneticity in a magnetization phenomenon of structures regardless of their atomic lattice is symmetrical or asymmetrical. It is assumed that a synchronous converse magnetization couples both piezomagnetic and flexomagnetic features into the material structure. The mathematical modeling begins with the Timoshenko beam model to find the governing equations and non-classical boundary conditions based on shear deformations. Flexomagneticity evolves at a small scale and dominant at micro/nanosize structures. Meanwhile, the well-known Eringen’s-type model of nonlocal strain gradient elasticity is integrated with the mathematical process to fulfill the scaling behavior. From the viewpoint of the solution, the displacement of the physical model after deformation is carried out as the analytical solution of the Galerkin weighted residual method (GWRM), helping us obtain the numerical outcomes on the basis of the simple end conditions. The best of our achievements display that considering shear deformation is essential for nanobeams with larger values of strain gradient parameter and small amounts of the nonlocal coefficient. Furthermore, we showed that the flexomagnetic (FM) effect brings about more noticeable shear deformations’ influence.

  • Flexomagneticity in Functionally Graded Nanostructures
    • Mohammad Malikan
    • Tomasz Wiczenbach
    • Victor Eremeev
    2022 Pełny tekst

    Functionally graded structures have shown the perspective of materials in a higher efficient and consistent manner. This study reports a short investigation by concentrating on the flexomagnetic response of a functionally graded piezomagnetic nano-actuator, keeping in mind that the converse magnetic effect is only taken into evaluation. The rule of mixture assuming exponential composition of properties along with the thickness is developed for the ferromagnetic bulk. Nonlocal effects are assigned to the model, respecting Eringen’s hypothesis. The derived equations deserve to be analytically solved. Therefore, numerical results are generated for fully fixed ends. It is denoted that the functionality grading feature of a magnetic nanobeam can magnify the flexomagnetic effect leading to high-performance nanosensors/actuators.

  • Fluconazole resistant Candida auris clinical isolates have increased levels of cell wall chitin and increased susceptibility to a glucosamine-6-phosphate synthase inhibitor
    • Garima Shahi
    • Mohit Kumar
    • Andrzej Skwarecki
    • Matt Edmondson
    • Atanu Banerjee
    • Jane Usher
    • Neil A.R. Gow
    • Sławomir Milewski
    • Rajendra Prasad
    2022 Pełny tekst Cell Surface

    In 2009 Candida auris was first isolated as fungal pathogen of human disease from ear canal of a patient in Japan. In less than a decade, this pathogen has rapidly spread around the world and has now become a major health challenge that is of particular concern because many strains are resistant to multiple class of antifungal drugs. The lack of available antifungals and rapid increase of this fungal pathogen provides an incentive for the development of new and more potent anticandidal drugs and drug combinatorial treatments. Here we have explored the growth inhibitory activity against C. auris of a synthetic dipeptide glutamine analogue, L-norvalyl-N3-(4-methoxyfumaroyl)-L-2,3- diaminopropanoic acid (Nva-FMDP), that acts as an inhibitor of glucosamine-6-phosphate (GlcN-6-P) synthase - a key enzyme in the synthesis of cell wall chitin. We observed that in contrast to FLC susceptible isolates of C. auris, FLC resistant isolates had elevated cell wall chitin and were susceptible to inhibition by Nva-FMDP. The growth kinetics of C. auris in RPMI-1640 medium revealed that the growth of FLC resistant isolates were 50–60% more inhibited by Nva-FMDP (8 g/ml) compared to a FLC susceptible isolate. Fluconazole resistant strains displayed increased transcription of CHS1, CHS2 and CHS3, and the chitin content of the fluconazole resistant strains was reduced following the Nva-FMDP treatment. Therefore, the higher chitin content in FLC resistant C. auris isolates may make the strain more susceptible to inhibition of the antifungal activity of the Nva-FMDP peptide conjugate

  • Fluid structure interaction study of non-Newtonian Casson fluid in a bifurcated channel having stenosis with elastic walls
    • Hasan Shahzad
    • Xinhua Wang
    • Abuzar Ghaffari
    • Kaleem Iqbal
    • Muhammad Bilal Hafeez
    • Marek Krawczuk
    • Wiktoria Wojnicz
    2022 Pełny tekst Scientific Reports

    Fluid–structure interaction (FSI) gained a huge attention of scientists and researchers due to its applications in biomedical and mechanical engineering. One of the most important applications of FSI is to study the elastic wall behavior of stenotic arteries. Blood is the suspension of various cells characterized by shear thinning, yield stress, and viscoelastic qualities that can be assessed by using non-Newtonian models. In this study we explored non-Newtonian, incompressible Casson fluid flow in a bifurcated artery with a stenosis. The two-dimensional Casson model is used to study the hemodynamics of the flow. The walls of the artery are supposed to be elastic and the stenosis region is constructed in both walls. Suitable scales are used to transform the nonlinear differential equations into a dimensionless form. The problem is formulated and discretized using Arbitrary Lagrangian–Eulerian (ALE) approach. The finite element method (FEM) technique is used to solve the system of equations, together with appropriate boundary conditions. The analysis is carried out for the Bingham number, Hartmann number, and Reynolds number. The graphical results of pressure field, velocity profile, and load on the walls are assessed and used to study the influence of hemodynamic effects on stenotic arteries, bifurcation region, and elastic walls. This study shows that there is an increase in wall shear stresses (WSS) with increasing values of Bingham number and Hartmann number. Also, for different values of the Bingham number, the load on the upper wall is computed against the Hartmann number. The result indicate that load at the walls increases as the values of Bingham number and Hartmann number increase.

  • Fluid–Structure Interaction methods for the progressive anatomical and artificial aortic valve stenosis
    • Marcin Nowak
    • Eduardo Divo
    • Wojciech P. Adamczyk
    2022 INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES

    Cardiovascular system diseases, as aortic valve stenosis, are the main cause of mortality and morbidity among patients. There is still a room for enhancement of the diagnostic and therapeutic procedures, which will lead to improvement of the treatment. One of the remedies are the computer tools to support the medical diagnoses and prostheses design. The development of a procedure for modeling the aortic valves: anatomical tricuspid valve and artificial bileaflet valve, still is a very challenging task. In presented work, the application of the novel, advanced moving mesh model, that consists of the coupling of the dynamic mesh smoothing and the overset mesh technique, to speed up the computation and improve the convergence and stability was shown. The real 2D and 3D vasculature and valve geometries were created based on the echocardiography images available in literature. The calculations of anatomical and artificial valve models were performed for the various severity of the atherosclerosis — not previously published for the bileaflet mechanical valve. The impact of calcification process onto natural and artificial aortic valves was assessed and compared.

  • Fluorescence Imaging Using Methylene Blue Sentinel Lymph Node Biopsy in Melanoma
    • Tomasz Cwalinski
    • Jarosław Skokowski
    • Wojciech Polom
    • Luigi Marano
    • Maciej Swierblewski
    • Kamil Drucis
    • Giandomenico Roviello
    • Natalia Cwalina
    • Leszek Kalinowski
    • Franco Roviello
    • Karol Polom
    2022 Surgical Innovation

    Introduction: Fluorescence imaging of sentinel node biopsy in melanoma is a novel method. Both indocyanine green (ICG) and methylene blue (MB) have fl uorescent properties. The aim of this study was to present, for the fi rst time in a clinical series of patients, the possible usage of MB as a fl uorescent dye for sentinel node biopsy during surgery for melanoma. Material and methods: Twenty patients with skin melanoma, who were candidates for sentinel node biopsy were enrolled in our study. All patients underwent simultaneous use of standard nanocolloid and blue dye. Transcutaneous visualization of the sentinel node, visualization of lymphatic channels as well as sentinel node fl uorescent visualization were all measured. We also performed calculations of Signal to Background ratios (SBR). Results: In 15% (3/20) of patients, the fl uorescent sentinel node was visible through the skin. The median SBR for the sentinel node visualization by fl uorescence was 3.15 (range, 2.7 – 3.5). Lymphatic channels were visible in lymphatic tissue via fl uorescence before visualization by the naked eye in 4 patients (20%). The median SBR ratio was 3.69 (range, 2.7 – 4.2). Sentinel nodes were visible by fl uorescence in 13 cases (65%). The median SBR ratio was 2.49 (range, 1.5 – 5.7). No factors were found to be associated with fl uorescent MB visualization of a sentinel node during biopsy. Conclusion: This is the fi rst clinical study presenting the usefulness of fl uorescent sentinel node biopsy in melanoma patients using MB as a fl uorophore. Further studies are necessary to provide methods for its ’ clinical implementation.

  • Fluorescence of nanodiamond cocktails: pH-induced effects through interactions with comestible liquids
    • Maciej Głowacki
    • Mateusz Ficek
    • Mirosław Sawczak
    • Anna Wcisło
    • Robert Bogdanowicz
    2022 Pełny tekst FOOD CHEMISTRY

    Fluorescent nanodiamonds with nitrogen-vacancy centers have become important nanoscale probes for sensing and imaging. The surface chemistry of the nanodiamonds influences their emission, interactions, and quantum properties. In this work, we propose to utilize fluorescent nanodiamonds as photostable markers for investigation of comestible liquids. We prepared nanodiamond/comestibles suspensions/cocktails with a wide range of pH levels and studied the samples via fluorescence, wettability, and zeta potential. The composition of the created cocktails revealed a strong impact on the properties of the nanodiamond and its surface chemistry, mainly induced by pH but also tuned by specific quenching compounds. Moreover, the stability of the nanodiamonds in the cocktail media was studied, along with various nature-originated compounds influencing their surface termination, polarity, and charge states. Thanks to the stability and biocompatibility of the nanodiamond, it can be applied in monitoring the condition of foodstuffs, and in the detection of toxins and pathogens in them.

  • Focused ion beam-based microfabrication of boron-doped diamond single-crystal tip cantilevers for electrical and mechanical scanning probe microscopy
    • Ewelina Gacka
    • Piotr Kunicki
    • Andrzej Sikora
    • Robert Bogdanowicz
    • Mateusz Ficek
    • Teodor Gotszalk
    • Ivo W. Rangelow
    • Krzysztof Kwoka
    2022 Pełny tekst MEASUREMENT

    In this paper, the fabrication process and electromechanical properties of novel atomic force microscopy probes utilising single-crystal boron-doped diamond are presented. The developed probes integrate scanning tips made of chemical vapour deposition-grown, freestanding diamond foil. The fabrication procedure was performed using nanomanipulation techniques combined with scanning electron microscopy and focused ion beam technologies. The mechanical properties of the cantilever were monitored by the measurement of thermally induced vibration of the cantilever after every fabrication step, allowing the mass changes in range of ng to be estimated. The endurance of the developed probes was tested during hundreds of topography measurements, which corresponds to a scanning length equal to 13.6 m, performed on a test sample in contact and lateral force microscopy modes. Analysis of the roughness parameters confirmed the extremely high wear resistance of the fabricated probes. The linear current voltage response on a highly-oriented pyrolytic graphite sample was recorded.

  • Foliate-Targeting Quantum Dots-β-Cyclodextrin Nanocarrier for Efficient Delivery of Unsymmetrical Bisacridines to Lung and Prostate Cancer Cells
    • Joanna Pilch
    • Patrycja Kowalik
    • Agata Kowalczyk
    • Piotr Bujak
    • Artur Kasprzak
    • Ewa Paluszkiewicz
    • Ewa Augustin
    • Anna M. Nowicka
    2022 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Targeted drug delivery by nanocarriers molecules can increase the efficiency of cancer treatment. One of the targeting ligands is folic acid (FA), which has a high affinity for the folic acid receptors, which are overexpressed in many cancers. Herein, we describe the preparation of the nanoconjugates containing quantum dots (QDs) and β-cyclodextrin (β-CD) with foliate-targeting properties for the delivery of anticancer compound C-2028. C-2028 was bound to the nanoconjugate via an inclusion complex with β-CD. The effect of using FA in QDs-β-CD(C-2028)-FA nanoconjugates on cytotoxicity, cellular uptake, and the mechanism of internalization in cancer (H460, Du-145, and LNCaP) and normal (MRC-5 and PNT1A) cells was investigated. The QDs-β-CD(C-2028)-FA were characterized using DLS (dynamic light scattering), ZP (zeta potential), quartz crystal microbalance with dissipation (QCM-D), and UV-vis spectroscopy. The conjugation of C-2028 with non-toxic QDs or QDs-β-CD-FA did not change the cytotoxicity of this compound. Confocal microscopy studies proved that the use of FA in nanoconjugates significantly increased the amount of delivered compound, especially to cancer cells. QDgreen-β-CD(C-2028)-FA enters the cells through multiple endocytosis pathways in different levels, depending on the cell line. To conclude, the use of FA is a good self-navigating molecule in the QDs platform for drug delivery to cancer cells.

  • Food Classification from Images Using a Neural Network Based Approach with NVIDIA Volta and Pascal GPUs
    • Ewa Tusień
    • Aleksandra Wilke
    • Joanna Woźna
    • Paweł Czarnul
    2022 Pełny tekst

    In the paper we investigate the problem of food classification from images, for the Food-101 dataset extended with 31 additional food classes from Polish cuisine. We adopted transfer learning and firstly measured training times for models such as MobileNet, MobileNetV2, ResNet50, ResNet50V2, ResNet101, ResNet101V2, InceptionV3, InceptionResNetV2, Xception, NasNetMobile and DenseNet, for systems with NVIDIA Tesla V100 (Volta) and NVIDIA GTX 1060 (Pascal) GPUs. We presented inference times corresponding to training the various considered network models, both using a desktop NVIDIA GTX 1060 GPU and an Intel i7-7000 CPU. Subsequently, we investigated the InceptionV3 model in more detail, best in the preliminary tests, regarding the impact of both learning rates (including both various fixed and variable rates) as well as batch sizes on the accuracy of classification, along with training times for various batch sizes. This allowed to identify better learning rate configurations as well as classification performance versus training time.

  • FOREIGN TRADE WITH CHINA: NO REASON FOR “GERMAN ANGST”
    • Franz Peter Lang
    • Oleksandr Melnychenko
    2022 Pełny tekst Współpraca Europejska

    Sankcje w związku z rosyjską agresją zbrojną przeciwko Ukrainie i naruszenie zwykłych światowych szlaków handlowych powodują w Niemczech obawy, że niemiecka gospodarka może zostać szantażowana handlem z silnym partnerem, tj. Chinami.Analiza danych dotyczących niemiecko-chińskiego handlu zagranicznego i jego wpływu na gospodarkę i zatrudnienie pokazuje, że Chiny są jednym z nielicznych na-jważniejszych partnerów handlowych, ale w żaden sposób nie zajmują dominującą pozycję. Współzależność, która nieuchronnie wynika ze stosunków handlowych, oka-zała się możliwa do opanowania, a nawet może zostać rozszerzona poprzez racjonalną politykę w Chinach.Aby móc ocenić możliwy przyszły rozwój sytuacji, globalne ambicje gospodarcze Chin rozpatrywane są na tle planowanych na dużą skalę projektów, realnego potenc-jału i obecnych słabości. Przy obecnym neomaoizmie pojawiają się jednak wątpliwości, czy normalne stosunki z przeludnionymi Chinami mogą być kontynuowane, a nawet rozszerzane

  • Forewarned Is Forearmed: Machine Learning Algorithms for the Prediction of Catheter-Induced Coronary and Aortic Injuries
    • Barbara Klaudel
    • Jacek Klaudel
    2022 Pełny tekst International Journal of Environmental Research and Public Health

    Catheter-induced dissections (CID) of coronary arteries and/or the aorta are among the most dangerous complications of percutaneous coronary procedures, yet the data on their risk factors are anecdotal. Logistic regression and five more advanced machine learning techniques were applied to determine the most significant predictors of dissection. Model performance comparison and feature importance ranking were evaluated. We identified 124 cases of CID in electronic databases containing 84,223 records of diagnostic and interventional coronary procedures from the years 2000–2022. Based on the f1-score, Extreme Gradient Boosting (XGBoost) was found to have the optimal balance between positive predictive value (precision) and sensitivity (recall). As by the XGBoost, the strongest predictors were the use of a guiding catheter (angioplasty), small/stenotic ostium, radial access, hypertension, acute myocardial infarction, prior angioplasty, female gender, chronic renal failure, atypical coronary origin, and chronic obstructive pulmonary disease. Risk prediction can be bolstered with machine learning algorithms and provide valuable clinical decision support. Based on the proposed model, a profile of ‘a perfect dissection candidate’ can be defined. In patients with ‘a clustering’ of dissection predictors, a less aggressive catheter and/or modification of the access site should be considered.

  • Formation of OH Radicals as Evidence of Intramolecular Hydrogen Migration in Cation-Induced Dissociation of Furan Molecules
    • Tomasz Wąsowicz
    2022 Romanian Journal of Physics

    We present the experimental results on a hydrogen atom migration preceding fragmentation of the furan molecules induced by the H3+ and C+ impact. The excited OH(A2Σ+) radical has been detected among the furan decomposition products using collision-induced emission spectroscopy. However, the OH moiety is absent in the furan ring skeleton, so detecting the OH(A2Σ+→X2Π) luminescence indicates the intramolecular H atom relocation prior to cation-induced fragmentation. Guided by the most recent theoretical calculations, the dissociation mechanism that governs the OH(A2Σ+) formation observed in this work is elucidated.

  • Fouling mechanisms in anoxic-aerobic sequencing batch membrane bioreactor based on adapted Hermia models and main foulant characteristics
    • Hossein Shams
    • Mohammad Reza Alavi Moghaddam
    • Reza Maknoon
    • Jacek Mąkinia
    • Mayam Hasani Zonoozi
    2022 JOURNAL OF ENVIRONMENTAL MANAGEMENT

    Various derivatives of Hermia models (complete pore blocking, intermediate pore blocking, cake layer formation, and standard pore blocking) and different assessments of foulant characteristics have long been used to determine the membrane fouling mechanisms. Accordingly, this study aims to adapt Hermia models and their combination according to the operating conditions of an anoxic-aerobic sequencing batch membrane bioreactor (A/O-SBMBR). In addition, fouling mechanisms of the A/O-SBMBR were assessed using these models along with the main foulant characteristics. Models fitting with the transmembrane pressure (TMP) data indicated that the intermediate-standard model was accounting for the increased fouling during the whole regular operating period, with the residual sum of squares (RSS) of 58.3. A more detailed study on the distinct stages of TMP curve showed that the intermediate-standard model had the best fit in stages of 2 and 3, with the RSS equal to 2.6 and 2.8, respectively. Also, the complete-standard model provided the best description of the fouling mechanism in stage 4, with the RSS of 12.5. Different analyzes revealed how the main foulant characteristics affect the occurrence of intermediate, complete and standard fouling mechanisms in the A/O-SBMBR, which is consistent with the fitting results of the adapted Hermia models. The modeling and experimental methods used in the presented study provided a valuable basis to prevent and control membrane fouling in membrane bioreactors.

  • FPGA Acceleration of Matrix-Assembly Phase of RWG-Based MoM
    • Tomasz Topa
    • Artur Noga
    • Tomasz Stefański
    2022 Pełny tekst IEEE Antennas and Wireless Propagation Letters

    In this letter, the field-programmable-gate-array accelerated implementation of matrix-assembly phase of the method of moments (MoM) is presented. The solution is based on a discretization of the frequency-domain mixed potential integral equation using the Rao-Wilton-Glisson basis functions and their extension to wire-to-surface junctions. To take advantage of the given hardware resources (i.e., Xilinx Alveo U200 accelerator card), nine independent processing paths/runtime efficient compute units are developed and synthesized. Numerical results provided for a quadrifilar spiral antenna mounted on a conductive handset box show that the proposed parallelization scheme performs 9.53× faster than a traditional (i.e., serial) central processing unit (CPU) MoM implementation, and about 1.67× faster than a parallel six-core CPU MoM implementation.

  • Fracture Surface Behavior of 34CrNiMo6 High-Strength Steel Bars with Blind Holes under Bending-Torsion Fatigue
    • Wojciech Macek
    • Ricardo Branco
    • José Domingos Costa
    • Jarosław Trembacz
    2022 Pełny tekst Materials

    The present study evaluates the fracture surface response of fatigued 34CrNiMo6 steel bars with transverse blind holes subjected to bending with torsion loading. The analysis of the geometric product specification was performed by means of height parameters Sx, functional volume parameters Vx, and fractal dimension Df. Surface topography measurements were carried out using an optical profilometer with focus variation technology. The experimental results show that the doubling the bending to torsion moment ratio B/T from B/T = 1 to B/T = 2, maintaining the same normal stress amplitude, greatly reduces both Sa, Vv as well as the fractal dimension Df of the analyzed specimen fractures by 32.1%, 29.8%, and 16.0%, respectively. However, as expected, a two-fold increase in the B/T ratio, maintaining the same normal stress amplitude, resulted in a larger number of cycles to fatigue crack initiation, Ni, which can be explained by the lower shear stress level. These experiments prove that parameters Sx, Vx, Df are smaller for larger Ni values, which is an important finding. In addition, it was found a high consistency of surface topography measurements for the two sides of the broken specimens. The proposed methodology is both reliable and applicable for other engineering applications involving different geometries and loading conditions.

  • Fracture surface formation of notched 2017A-T4 aluminium alloy under bending fatigue
    • Wojciech Macek
    2022 Pełny tekst INTERNATIONAL JOURNAL OF FRACTURE

    The effect of cyclic loading on facture surface topology in notched components made by aluminium alloys is not completely clear. Fractogra-phy and fracture mechanics can help to understand this interdependency. This paper aims to study the distribution of the fracture surface roughness of notched 2017A-T4 aluminium alloy after bending fatigue using an optical focus-variation surface measurement technique by applying the fracture zone concept. The effects of stress level at the notch root and the load ratio on fatigue crack growth and fracture surfaces are analysed. Profile and areal surface parameters of four fracture surface regions were investigated at incre-mental crack lengths of the specimens. Studies have confirmed that the surface areas associated with the main stages of fatigue phenomenon (i.e. crack initiation , crack propagation, and final rupture) have significant differences in roughness which can be explained by the different loading scenarios. Overall, fatigue fracture surfaces have smallest roughness values at the crack initiation stage and a gradual increase during the fatigue crack growth stage.

  • Fracture surface topography investigation and fatigue life assessment of notched austenitic steel specimens
    • Wojciech Macek
    • Grzegorz Robak
    • Krzysztof Żak
    • Ricardo Branco
    2022 Pełny tekst ENGINEERING FAILURE ANALYSIS

    The objectives of this study were to investigate the fracture surface topography of X8CrNiS18-9 austenitic stainless-steel specimens for different loadings and notch radii and to supplement the knowledge about the fracture mechanisms for fatigue performance. Cases with three different values of the notch radius ρ and the stress amplitude σa were analysed. The fracture topographies were quantified by the areas over their entire surfaces with the aid of an optical confocal measurement system. The results showed a well-correlated root mean square height Sq and void volume Vv, identifying the characteristics of the entire fracture method. A fracture surface topography fatigue damage model was developed based on the product of the stress amplitude σa by the Sq to the Vv ratio. Overall, the predictions were close to the fatigue lives found in the experiments.

  • Fragility analysis of structural pounding between adjacent structures arranged in series with various alignment configurations under near‑field earthquakes
    • Fahimeh Ebrahimiyan
    • Ali Mohammad Hadianfard
    • Hosein Naderpour
    • Robert Jankowski
    2022 Pełny tekst Bulletin of Earthquake Engineering

    A major cause of local to total damages is related to structural pounding in a large number of past earthquakes. In general, these collisions take place as a result of differences in the dynamic characteristics of the colliding structures. To acquire a better perception of the behavior of structures, in this paper, three structures featuring different heights are modeled in series and with various configurations next to each other in OpenSees. To determine the collision effects of the structures, three different configurations of 4-, 8- and 12-story adjacent reinforced concrete special moment resisting frames were considered. Then, by conducting an incremental dynamic analysis, their structural seismic limit state capacities were assessed via 20 near-field record subsets recommended by FEMA-P695. At last, for the above adjacent buildings with various separation distances and configurations, the fragility curves were determined, and the probability of exceedance from the primary Hazus-MH failure criteria was estimated. In addition, the results were compared with those obtained when this phenomenon did not take place for buildings to have a better perception of the pounding phenomenon. The results of the analyses show that arranging adjacent structures in series greatly affects the collapse capacities of the colliding structures. In addition, in the case when the shorter structure is placed in the middle of two taller structures, it results in the most critical situation among all configurations, and in this case, a higher reduction is observed in the structural performance levels.

  • Fragmentomic analysis of biopeptides in silico released from milk proteins
    • Anna Iwaniak
    • Antoni Taraszkiewicz
    2022 Pełny tekst POLISH JOURNAL OF NATURAL SCIENCES

    The fragmentomic-assisted method was employed to predict the biological potential of peptides derived from milk proteins hydrolyzed by papain and bromelain. Firstly, protein sequences were acquired from the BIOPEP-UWM database and then hydrolyzed by the above enzymes using a BIOPEP-UWM tool called “Enzyme(s) action”. The released peptides were defined as parent peptides and further analyzed for the presence of shorter peptidic regions with documented bioactivity as well as their likelihood to be bioactive. The results revealed the bioactive potential of the released parent peptides. β-Casein was found as the best source of biopeptides. Although this finding is consistent with literature data, the new parent peptide i.e., PVQPFTESQSLTLTDVENLHLPPLLLQSWMHQPHQPLPPTVMFPPQSVLSLSQSK, produced by the action of bromelain might be considered as a new strategic zone due to the presence of multi-active regions. Some parent peptides theoretically produced from milk proteins turned out to be fully bioactive. Despite the usefulness of the tools for peptide bioactivity prediction, the critical thinking while planning the application of such data in future experiments would thus appear to be a worthwhile line of inquiry.

  • From fluid mechanics backgrounds to modern field theory
    • Janusz Badur
    • Tomasz Ochrymiuk
    • Tomasz Kowalczyk
    • Waldemar Dudda
    • Paweł Ziółkowski
    2022 ACTA MECHANICA

    Our presentation keeps a historical line of reasoning, since we start from old concepts of fluid mechanics and finish on concepts of modern field theory. We want to show that some facts from the nature phenomena, which have firstly been discovered on the ground of fluid mechanics, were next incorporated into physics and later become the important pattern for whole mathematical physics. Especially, well-known continuum models, which have firstly been found in fluid mechanics, next became the key patterns in theoretical astronomy, electrodynamics, string theory, etc. Technically, it was possible, since in the 18th-century, many researchers, like Newton, Wallis, Euler, Clairaut, Lagrange, have developed fluid mechanics simultaneously with whole physics, therefore fluid mechanics analytical tools, step by step, become the whole physic ones. In other words, fluid mechanics played a leading role in those days and undoubtedly formed the basis for the development of many leading areas of physics

  • From Individual to Collective: Intelligence Amplification with Bio-Inspired Decisional DNA and its Extensions
    • Edward Szczerbicki
    2022 Pełny tekst

    In nature, deoxyribonucleic acid (DNA) contains the genetic instructions used in the development and functioning of all known living organisms. The idea behind our vision is to develop an artificial system, an architecture that would support discovering, adding, storing, improving and sharing information and knowledge among agents and organizations through experience. We propose a novel Knowledge Representation (KR) approach in which experiential knowledge is represented by Set of Experience (SOE), and is carried into the future by Decisional DNA (DDNA). This research has enormous and exciting potential of opening entirely new and so far not conceptually conceived horizons in developing and using collective intelligence to find solutions to different problems.

  • From the pills to environment – Prediction and tracking of non-steroidal anti-inflammatory drug concentrations in wastewater
    • Katarzyna Kołecka
    • Magdalena Gajewska
    • Magda Caban
    2022 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    The extend of environment pollution by pharmaceuticals is in a stage that required more automatic and integrated solutions. The non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most popular pharmaceutical in the world and emerging pollutants of natural waters. The aim of the paper was to check the correlation of the sales data of selected NSAIDs (ibuprofen, naproxen, diclofenac) and their concentration in the WWTP in order to enable predicting their loads, having only the sales data. For calculations, we apply three discharge scenarios (the fates between purchased to the presence in influents), having in mind that some part of sold mass can be improperly dispose to sewage system. To support predictions, chemical analysis was conducted in two conventional wastewater treatment plants (WWTPs) located in Poland during 2018 and 2020, thereby before and during pandemic situation. The NSAIDs concentration in the influent was higher than that which would be obtained if all of the administrated mass of the pharmaceutical went through the metabolic pathway of transformation. This means that substantial mass of sold NSAIDs in improperly dispose to sewage system, and this factor need to be taken into account in future predictions. Furthermore, results indicate that the variance of naproxen and diclofenac concentrations in the influent has no correlation with relatively stable sales throughout whole year. The pandemic situation had yet no direct effect to diclofenac concentrations in influents, despite observed increasing of sales. It was calculated that more than 60 kg of diclofenac was discharged into the Baltic Sea in 2018, and 20 kg in the first half of 2021 from two tested WWTPs. The presence of 4OH-diclofenac in effluents often in higher concentration compared to diclofenac mean that this still biologically active compound need to be taken into account in future risk assessment.

  • From tryptophan to novel mitochondria-disruptive agent, synthesis and biological evaluation of 1,2,3,6-tetrasubstituted carbazoles
    • Milena Witkowska
    • Natalia Maciejewska
    • Małgorzata Ryczkowska
    • Mateusz Olszewski
    • Maciej Bagiński
    • Sławomir Makowiec
    2022 Pełny tekst EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY

    Mitochondrial targeting plays an important role in anticancer therapy. The Mn(III)-promoted cyclization of 5- (1H-indol-3-yl)-3-oxopentanoic acid allow to obtain novel substituted carbazole derivatives that can act as mitochondria-disruptive agents. The starting materials used for the synthesis of these new aminocarbazoles are oxopentanoate derivatives of tryptophan. The scope and limitation of this method of synthesis are determined by a series of experiments. The prepared carbazole derivatives are screened for their in vitro anticancer activity against a broad panel of human cancer cells and normal cell lines. Among the tested compounds, the most active ones are examined further against human colon cancer cells (HCT-116) and human bone osteosarcoma (U-2 OS), in complex in vitro cellular assays, including studies on cell cycle distribution, intracellular compartmentalization, antimigratory properties, mitochondrial generation of reactive oxygen species, DNA damage, and type of cellular death. The results reveal that the synthesized compounds display potent oxidative activity inducing massive accumulation of DNA double-strand breaks, which lead to a parallel change in the assembly of mitochondria causing their dysfunction. These findings provide new leads for the treatment of colon cancer and osteosarcoma.

  • Functional fluorine-doped tin oxide coating for opto-electrochemical label-free biosensors
    • Dariusz Burnat
    • Petr Sezemsky
    • Katarzyna Lechowicz
    • Marcin Koba
    • Marta Janczuk-Richter
    • Monika Janik
    • Vitezslav Stranak
    • Joanna Niedziółka-Jönsson
    • Robert Bogdanowicz
    • Mateusz Śmietana
    2022 Pełny tekst SENSORS AND ACTUATORS B-CHEMICAL

    Sensors operating in multiple domains, such as optical and electrochemical, offer properties making biosensing more effective than those working in a single domain. To combine such domains in one sensing device, materials offering a certain set of properties are required. Fluorine-doped tin oxide (FTO) thin film is discussed in this work as functional optically for guiding lossy modes and simultaneously electrochemically, i.e. as a conductive material for a working electrode. Performance of the FTO-based optical fiber lossy-mode resonance (LMR) sensor in both optical and electrochemical domains is analyzed. Additionally, to enhance applicability of the sensor, its probe-like reflection configuration has been developed. It is found that FTO may be considered as a promising alternative for other thin conductive oxides (TCO), such as indium tin oxide (ITO) that has been often applied up to date in various dual-domain sensing concepts. In the optical domain, the sensitivity of the FTO-LMR sensor to external refractive index (RI) has reached 450 nm/RIU in the RI range of 1.33–1.40 RIU. In the electrochemical domain, in turn, the response for FTO electrode in 1,1′-Ferrocenedimethanol solution has been reached with RedOx current low peak-to-peak separation. In contrast to the ITO-LMR sensors, the FTO-LMR counterparts exhibit a significant influence of applied potential on LMR wavelength shift in a wide potential range. It is shown using streptavidin as a target biomaterial that label-free biosensing applications of the FTO-LMR approach are possible. The dual-domain functionality allows for cross-verification between readouts received in both the domains, as well as enhancement of optical sensitivity when cross-domain interactions are applied.

  • Functionalized nanodiamonds as a perspective green carbo-catalyst for removal of emerging organic pollutants
    • Robert Bogdanowicz
    2022 Pełny tekst CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE

    Rapid industrial and urban development jointly with rising global population strongly affect the large-scale issues with drinking, groundwater, and surface water pollution. Concerns are not limited to environmental issues but also human health impact becoming serious global aspect. Organic pollution becomes a primarily serious hazard, therefore, the novel sophisticated approaches to treat them are thoroughly investigated. Among numerous materials, functionalized nanodiamonds are specific versatile nanocarbon material attracted ample attention thanks to their exceptional chemical, optical and electronic properties beneficial in the decomposition of harmful organic chemicals. This work delivers a comprehensive review of progress and perspectives on the green-friendly nanodiamonds, which are suitable for the degradation of emerging organic pollutants using numerous approaches utilizing them as an electro-oxidation catalyst; photocatalyst; oxidation agent, or adsorbing surface. Novel modification strategies of nanodiamonds (i.e., persulfates, oxides, or metals) remarkably improve pollutant removal efficiency and facilitate charge transfer and surface regeneration. Furthermore, we evaluated also the influence of various factors like pH, natural organic matters, or radical scavengers on the removal efficiency combining them with nanodiamond properties. The identified missing research gaps and development perspectives of nanodiamond surfaces in water remediation relating to other nanocarbon and metal catalysts were also here described.

  • Fundamentals of Data-Driven Surrogate Modeling
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2022

    The primary topic of the book is surrogate modeling and surrogate-based design of high-frequency structures. The purpose of the first two chapters is to provide the reader with an overview of the two most important classes of modeling methods, data-driven (or approx-imation), as well as physics-based ones. These are covered in Chap-ters 1 and 2, respectively. The remaining parts of the book give an exposition of the specific aspects of particular modeling methodolo-gies and their applications to solving various simulation-driven de-sign tasks such as parametric optimization or uncertainty quantifica-tion. Data-driven models are by far the most popular types of surro-gates. This is due to several reasons, including versatility, low evalu-ation cost, a large variety of matured methods, and—important from the point of view of practical utility—widespread availability through third-party toolboxes implemented in programming envi-ronments such as Matlab. This chapter covers the fundamentals of approximation-based modeling. We discuss the surrogate modeling flow, design of experiments, selected modeling methods (e.g., kriging, radial basis functions, support vector regression, or polyno-mial chaos expansion), as well as discuss model validation ap-proaches. The presented material is intended to provide the readers who are new to the subject with the basics necessary to understand the remaining parts of the book. On the other hand, it is by no means exhaustive, and the readers interested in a more detailed exposition can refer to a rich literature of the subject.