Publications Repository - Gdańsk University of Technology

Page settings

polski
Publications Repository
Gdańsk University of Technology

Show publications from the year

Recent items

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

    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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text

    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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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.

  • Friction Resistances in Internal Gear Pump with Modified Sickle Made of Plastic
    • Krzysztof Towarnicki
    • Michał Stosiak
    • Piotr Antoniak
    • Tadeusz Lesniewski
    • Kamil Urbanowicz
    • Paweł Śliwiński
    2022

    This paper presents modifications of the sickle insert (constructional and material) made in a gear pump with internal meshing. The introduced design change consists in making an incision in the sickle insert. Due to this treatment, the races of the insert are pressed against the apex wheels of the gears. The introduced compensation causes a smaller drop in pump efficiency with increasing discharge pressure. The article describes the measuring stand and presents the measurement results. Measurements of the frictional resistance between the material of the gears and the insert material used during the measurements were carried out for the selected parameters of the pump operation. Differences in the frictional resistance were obtained between the POM material used for the sickle insert and the metal pin which reflects the material of the gear. The obtained results confirm that the increased pressure and speed of friction between cooperating elements causes increased frictional resistance, which was confirmed by measurements of torque changes on the pump shaft with the change of discharge pressure and different rotational speeds of the pump. The performed tests will allow to direct the work in order to make an optimal insert that meets the requirements of the constructed (prototype) pump with increased efficiency at higher pumping pressures. This will allow the evelopment of a pump with plastic displacement elements, so that the described pump will be able to be used in the future, inter alia, in the pharmaceutical and food industries.

  • 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 Full text

    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 Full text 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 Full text 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 Full text 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 Full text 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.

  • Fundamentals of Physics-Based Surrogate Modeling
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2022

    Chapter 1 was focused on data-driven (or approximation-based) modeling methods. The second major class of surrogates are physics-based models outlined in this chapter. Although they are not as popular, their importance is growing because of the challenges related to construction and handling of approximation surrogates for many real-world problems. The high cost of evaluating computational models, nonlinearity of system responses, dimensionality issues as well as combinations of these factors, may lead to a situation, where setting up a data-driven model is not possible or at least not practical. On the other hand, incorporation of the problem-specific knowledge, typically in the form of a lower-fidelity computational model, often alleviates the aforementioned difficulties. The enhancement of the low-fidelity models using a limited amount of high-fidelity data is the essence of physics-based surrogate modeling. This chapter provides a brief characterization of this class of surrogates, explains the concept and various types of low-fidelity models, as well as outlines several specific modeling approaches, also in the context of surrogate-assisted optimization.

  • Galerkin Finite Element Process for Entropy Production and Thermal Evaluation of Third-Grade Fluid Flow: A Thermal Case Study
    • Faisal Shahzad
    • Wasim Jamshed
    • El Sayed M. Tag El Din
    • Rabia Safdar
    • Nor Air Azeany Mohd Nazir
    • Rabha W. Ibrahim
    • Syed M. Hussain
    • Ikram Ullah
    • Muhammad Bilal Hafeez
    • Marek Krawczuk
    2022 Full text Applied Sciences-Basel

    : A fluid’s moving class improves its heat transmission capability, as well as its rigidity, owing to multivariate molecule suspension. In this way, nanofluids are superior to common fluids. In this study, we evaluated the features of ease and heat transfer. Furthermore, we investigated permeable media, heat source, variable heat conductivity, and warm irradiation results. A mathematical technique known as the Galerkin finite element (G-FEM) approach was used to solve the supervising conditions. Third-grade nanofluid (TGNF), which consists of two types of nanoparticles (NPs), single-walled carbon nanotubes (SWCNT), and multi-walled carbon nanotubes (MWCNTs) distributed in a base liquid of carboxymethyl cellulose (CMC) water, was used for this examination. The main conclusion of this study is that MWCNT-CMC nanofluid has a higher heat transfer velocity than SWCNT-CMC nanofluid. The entropy of the framework can be increased by adjusting the thermal conductivity. Additionally, we found that increasing the main volume section decreases the speed but increases the dispersion of atomic energy. In order to separately account for the development properties of inertial forces and shallow heat dispersion forces, Reynolds and Brinkman values can be used to accelerate the entropy rate of the heating framework.

  • Galerkin formulations with Greville quadrature rules for isogeometric shell analysis: Higher order elements and locking
    • T.j.r. Hughes
    • Zhihui Zou
    • M.a. Scott
    • Roger Sauer
    • E.j. Savitha
    2022

    We propose new Greville quadrature schemes that asymptotically require only four in-plane points for Reissner-Mindlin (RM) shell elements and nine in-plane points for Kirchhoff-Love (KL) shell elements in B-spline and NURBS-based isogeometric shell analysis, independent of the polynomial degree of the elements. For polynomial degrees 5 and 6, the approach delivers high accuracy, low computational cost, and alleviates membrane and transverse shear locking.

  • Game-based Sprint retrospectives: multiple action research
    • Adam Przybyłek
    • Marta Albecka
    • Olga Springer
    • Wojciech Kowalski
    2022 Full text EMPIRICAL SOFTWARE ENGINEERING

    In today’s fast-paced world of rapid technological change, software development teams need to constantly revise their work practices. Not surprisingly, regular reflection on how to become more effective is perceived as one of the most important principles of Agile Software Development. Nevertheless, running an effective and enjoyable retrospective meeting is still a challenge in real environments. As reported by several studies, the Sprint Retrospective is an agile practice most likely to be implemented improperly or sacrificed when teams perform under pressure to deliver. To facilitate the implementation of the practice, some agile coaches have proposed to set up retrospective meetings in the form of retrospective games. However, there has been little research-based evidence to support the positive effects of retrospective games. Our aim is to investigate whether the adoption of retrospective games can improve retrospective meetings in general and lead to positive societal outcomes. In this paper, we report on an Action Research project in which we implemented six retrospective games in six Scrum teams that had experienced common retrospective problems. The received feedback indicates that the approach helped the teams to mitigate many of the “accidental difficulties” pertaining to the Sprint Retrospective, such as lack of structure, dullness, too many complaints, or unequal participation and made the meetings more productive to some degree. Moreover, depending on their individual preferences, different participants perceived different games as having a positive impact on their communication, motivation-and-involvement, and/or creativity, even though there were others, less numerous, who had an opposite view. The advantages and disadvantages of each game as well as eight lessons learned are presented in the paper.

  • Gdańsk Urban Initiative Laboratory
    • Joanna Bach-Głowińska
    • Jacek Łubiński
    • Karolina Krośnicka
    • Joanna Tobolewicz
    2022

    Gdansk is Poland's principal seaport, situated on the southern edge of the Gdansk Bay on the Baltic Sea. The city is the capital and largest city of the Pomeranian Voivodeship. Gdansk, in a conurbation with the city of Gdynia and the resort town of Sopot, and suburban communities, jointly forms Poland's fourth largest metropolitan area, with a population approaching 1.4 million. The pathways towards the Micro ULL FWE Nexus Square were established together by academics, city experts, business partners, and international experts as stakeholders. The several thematic Urban Living Labs undertaken within carefully selected groups had created chances for user friendly innovations. The integrated multi-channel monitoring system will allow for the detailed tracking of individual use of media by devices on board.

  • Gender differences in the perception of the Quality of College Life in Spanish University
    • Juan Jose Blazquez-Resino
    • Edyta Gołąb-Andrzejak
    • Santiago Gutierrez-Broncano
    2022 Full text International Journal of Intelligent Enterprise

    Through the current research, we intend to analyse how students differ in their levels of quality of college life (QCL) according to gender, and how this relates to overall quality of life (QoL) and loyalty [measured by Identification and word of mouth (WoM)] to their specific university. The survey included 243 students attending public university in Spain. The results obtained through the analysis of data allow affirming that there are differences between women and men both in the configuration of the quality of their college life and in its effect on the loyalty shown towards the college. This paper contributes towards an improved comprehension regarding the differences between the students according to their gender, so that managers can develop strategies better adapted to students.

  • Generalized Dobrushin Coefficients on Banach Spaces
    • Wojciech Bartoszek
    • Marek Beśka
    • Wiktor Florek
    2022 Full text Bulletin of the Iranian Mathematical Society

    The asymptotic behavior of iterates of bounded linear operators (not necessarily positive), acting on Banach spaces, is studied. Through the Dobrushin ergodicity coefficient, we generalize some ergodic theorems obtained earlier for classical Markov semigroups acting on L1 (or positive operators on abstract state spaces).

  • Generalized Dold sequences on partially-ordered sets
    • Grzegorz Graff
    • Jacek Gulgowski
    • Małgorzata Lebiedź
    2022 Full text ELECTRONIC JOURNAL OF COMBINATORICS

    Dold sequences constitute an important class of integer sequences that play an important role in combinatorics, number theory, topology and dynamical systems. We generalize the notion of Dold sequence for the case of partially ordered sets and describe their properties. In particular we give two alternative descriptions of generalized Dold sequences: by some class of elementary sequences as well as by different generalized arithmetical functions, both defined on a partially ordered set. We also define vector Dold sequences and show their combinatorial interpretation in terms of periodic points.

  • Generalized Formulation of Response Features for Reliable Optimization of Antenna Input Characteristics
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2022 Full text IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION

    Electromagnetic (EM)-driven parameter adjustment has become imperative in the design of modern antennas. It is necessary because the initial designs rendered through topology evolution, parameter sweeping, or theoretical models, are often of poor quality and need to be improved to satisfy stringent performance requirements. Given multiple objectives, constraints, and a typically large number of geometry parameters, the design closure should be carried out through numerical optimization. Unfortunately, standard algorithms entail high CPU expenses and are prone to failure. Feature-based optimization (FBO) is one of the methods developed to alleviate these difficulties by reformulating the design task in terms of the characteristic points extracted from EM-simulated responses. FBO capitalizes on a less nonlinear relationship between the feature point coordinates and antenna dimensions as compared to the original responses (e.g., frequency characteristics). This leads to flattening the functional landscape to be handled, faster convergence of the optimization algorithms, and a possibility of mitigating the issues pertinent to multi-modality. Notwithstanding, the response features have to be individually defined for each type of antenna response and tailored to a particular type of design specifications. This requires user experience and hinders a widespread application of FBO. This paper proposes a generalized and unified feature point definition, which is suitable for majority of typical antenna input characteristics (narrow-, multi-band, enhanced bandwidth, wideband), and performance specifications (matching improvement, bandwidth enhancement, mixture thereof). Our framework allows for an automated definition of the feature points given the performance specifications, along with their extraction from EM-simulated responses. The operation of the framework is illustrated using a range of planar antennas and favorably compared to conventional (non-feature-based) design closure task formulation.

  • Generalized regression neural network and fitness dependent optimization: Application to energy harvesting of centralized TEG systems
    • Adeel Mirza
    • Syed Kamran Haider
    • Abbas Ahmed
    • Ateeq Ur Rehman
    • Muhammad Shafiq
    • Mohit Bajaj
    • Hossam M. Zawbaa
    • Paweł Szczepankowski
    • Salah Kamel
    2022 Full text Energy Reports

    The thermoelectric generator (TEG) system has attracted extensive attention because of its applications in centralized solar heat utilization and recoverable heat energy. The operating efficiency of the TEG system is highly affected by operating conditions. In a series-parallel structure, due to diverse temperature differences, the TEG modules show non-linear performance. Due to the non-uniform temperature distribution (NUTD) condition, several maximum power points (MPPs) appear on the P/V curve. In multiple MPPs, the true global maximum power points (GMPP) are very important for optimum action. The existing conventional technologies have slow tracking speed, low productivity, and unwanted fluctuations in voltage curves. To overcome the TEG system behavior and shortcomings, A novel control technology for the TEG system is proposed, which utilizes the improved generalized regression neural network and fitness dependent optimization (GRNNFDO) to track the GMPP under dynamic operating conditions. Conventional TEG system control techniques are not likely to trace true GMPP. Our novel GRNNFDO can trace the true GMPP for NUTD and under varying temperature conditions In this article, some major contributions in the area of the TEG systems are investigated by solving the issues such as NUTD global maxima tracking, low efficiency of TEG module due to mismatch, and oscillations around optimum point. The results of GRNNFDO are compared with the Cuckoo-search algorithm (CSA), and grasshopper optimization (GHO) algorithm and particle swarm optimization (PSO) algorithm. Results of GRNNFDO are verified with experiments and authenticated with MATLAB/SIMULINK. The proposed GRNNFDO control technique generates up to 7% more energy than PSO and 60% fast-tracking than meta-heuristic algorithms.

  • Genetic and pharmacologic proteasome augmentation ameliorates Alzheimer’s-like pathology in mouse and fly APP overexpression models
    • Paweł Wityk
    • E. Sandra Chocron
    • Erin Munkácsy
    • Harper S. Kim
    • Przemyslaw Karpowicz
    • Nisi Jiang
    • Van Skike E. Candice
    • Nicholas DeRosa
    • Banh Q. Andy
    • Palavicini P. Juan
    • Leszek Kalinowski
    • Veronica Galvan
    • Pawel A. Osmulski
    • Elzbieta Jankowska
    • Maria Gaczynska
    • Andrew M. Pickering
    2022 Full text Science Advances

    The proteasome has key roles in neuronal proteostasis, including the removal of misfolded and oxidized proteins, presynaptic protein turnover, and synaptic efficacy and plasticity. Proteasome dysfunction is a prominent feature of Alzheimer’s disease (AD). We show that prevention of proteasome dysfunction by genetic manipulation delays mortality, cell death, and cognitive deficits in fly and cell culture AD models. We developed a transgenic mouse with neuronal-specific proteasome overexpression that, when crossed with an AD mouse model, showed reduced mortality and cognitive deficits. To establish translational relevance, we developed a set of TAT-based proteasome-activating peptidomimetics that stably penetrated the blood-brain barrier and enhanced 20S/26S proteasome activity. These agonists protected against cell death, cognitive decline, and mortality in cell culture, fly, and mouse AD models. The protective effects of proteasome overexpression appear to be driven, at least in part, by the proteasome’s increased turnover of the amyloid precursor protein along with the prevention of overall proteostatic dysfunction.

  • Genetic and pharmacologic proteasome augmentation ameliorates Alzheimer’s-like pathology in mouse and fly APP overexpression models
    • E. Sandra Chocron
    • Erin Munkácsy
    • Harper S. Kim
    • Przemyslaw Karpowicz
    • Nisi Jiang
    • Candice E. Van Skike
    • Nicholas DeRosa
    • Andy Q. Banh
    • Juan P. Palavicini
    • Paweł Wityk
    • Leszek Kalinowski
    • Veronica Galvan
    • Pawel A. Osmulski
    • Elzbieta Jankowska
    • Maria Gaczynska
    • Andrew M. Pickering
    2022 Full text Science Advances

    The proteasome has key roles in neuronal proteostasis, including the removal of misfolded and oxidized proteins, presynaptic protein turnover, and synaptic efficacy and plasticity. Proteasome dysfunction is a prominent feature of Alzheimer’s disease (AD). We show that prevention of proteasome dysfunction by genetic manipulation delays mortality, cell death, and cognitive deficits in fly and cell culture AD models. We developed a transgenic mouse with neuronal-specific proteasome overexpression that, when crossed with an AD mouse model, showed reduced mortality and cognitive deficits. To establish translational relevance, we developed a set of TAT-based proteasome- activating peptidomimetics that stably penetrated the blood-brain barrier and enhanced 20 S /26 S proteasome activity. These agonists protected against cell death, cognitive decline, and mortality in cell culture, fly, and mouse Downloaded from https://www.science.org at Medical University of Gdansk on June 11, 2022 AD models. The protective effects of proteasome overexpression appear to be driven, at least in part, by the pro- teasome’s increased turnover of the amyloid precursor protein along with the prevention of overall proteostatic dysfunction.

  • Geodezyjne wyznaczanie przemieszczeń pionowych obiektów inżynierskich z pomiarów uzyskanych metodą niwelacji hydrostatycznej
    • Waldemar Kamiński
    2022 Inżynieria Morska i Geotechnika

    Niwelacja hydrostatyczna (NH) jest obecnie często stosowaną metodą wyznaczenia przemieszczeń pionowych obiektów inżynierskich takich jak: mosty, wiadukty, estakady, tunele, wysokie budynki, obiekty zabytkowe, specjalistyczne obiekty inżynierskie (np. synchrotron), hale sportowe, widowiskowe, itp. Zastosowane w systemach niwelacji hydrostatycznej (SNH) sensory (czujniki) pomiarowe obejmują sensor referencyjny (RS) oraz czujniki umieszczone w punktach kontrolowanych (PK). Sensor referencyjny jest to czujnik umieszczony w takim miejscu i w takim punkcie, który w założeniach teoretycznych nie podlega przemieszczeniom pionowym i w stosunku do jego wysokości wyznaczane są przemieszczenia PK. Zasada NH wynika z prawa Bernoulliego. Wykorzystując w NH prawo Bernoulliego, należy uwzględnić między innymi następujące parametry: ciśnienie atmosferyczne, siłę grawitacji, gęstość cieczy przepływającej przez sensory pomiarowe. Wymienione parametry wyznaczane są z pewnymi błędami średnimi mającymi wpływ na oszacowanie dokładności rezultatów przemieszczeń pionowych. Należy dodać, że w literaturze przedmiotu przedstawiono szereg prac dotyczących między innymi analiz dokładności indywidualnych wymienionych wyżej parametrów i ich wpływu na otrzymane przemieszczenia pionowe. W niniejszym artykule przedstawiono koncepcję geodezyjnego wyznaczania przemieszczeń SNH, oceny dokładności i istotności otrzymanych wielkości. Do oceny dokładności wykorzystano macierze kofaktorów (estymatorów wariancji). Posługując się modelem kinematycznym przemieszczających się PK badanego obiektu inżynierskiego przedstawiono problematykę predykcji przemieszczeń pionowych na dowolną epokę pomiarową. Wyznaczono także współczynnik korelacji liniowej Pearsona dla analizowanych w artykule parametrów. Przemieszczenia pionowe i analizę dokładności uzyskanych wartości wykonano dla zmodyfikowanego przykładu praktycznego zaczerpniętego z literatury przedmiotu [2]. Natomiast problem predykcji przedstawiono w oparciu o symulowane wyniki pomiaru przyspieszeń trzech PK badanego obiektu i ich błędów średnich. Prezentowane opracowanie jest uzupełnieniem i rozszerzeniem teoretyczno- empirycznych analiz przedstawionych w pracy [5].

  • Glass-ceramic joining of Fe22Cr porous alloy to Crofer22APU: interfacial issues and mechanical properties
    • Fabiana D'Isanto
    • Milena Salvo
    • Sebastian Molin
    • Damian Koszelow
    • Hassan Javed
    • Sufyan Akram
    • Andreas Chrysanthou
    • Federico Smeacetto
    2022 Full text CERAMICS INTERNATIONAL

    This work deals with the joining of porous Fe22Cr ferritic stainless steel to a dense Crofer22APU plate by using a silica-based, Ba-containing glass-ceramic. The chemical and interfacial stability and the mechanical properties of the joints were evaluated before and after thermal ageing at 700 ◦C for 500hrs. The sintering behaviour of the glass was assessed by using heating stage microscopy (HSM) to study the influence of a porous metal substrate on the shrinkage of the joining material. Scanning electron microscopy revealed that there were no defects or cracks at the porous alloy/glass-ceramic interface for both the as-joined samples and the samples after thermal ageing at 700 ◦C for 500 h. However, at this exposure temperature, the porous alloy started to form an oxide scale at the interface with the glass-ceramic and the internal surface of the porous alloy. Finally, the evaluation of the mechanical properties by tensile testing showed that the properties were not affected by thermal ageing at 700 ◦C.

  • Global defensive secure structures
    • Michał Małafiejski
    • Kacper Wereszko
    2022

    Let S ⊂ V (G) for a given simple non-empty graph G. We define for any nonempty subset X of S the predicate SECG,S(X) = true iff |NG[X]∩S| ≥ |NG[X]\S|. Let H be a non-empty family of graphs such that for each vertex v ∈ V (G) there is a subgraph H of G containing v and isomorphic to a member of H. We introduce the concept of H-alliance extending the concept of global defensive secure structures. By an H-alliance in a graph G we mean a set S ⊂ V (G) such that (1) each vertex v ∈ S belongs to a subgraph H of G that is isomorphic to a member of H, and (2) for each H ⊂ G[S] isomorphic to a member of H, SECG,S(V (H)) = true. If S is also a dominating set of G, we call it a global H-alliance of G. If H = {K1}, then such an H-alliance we call a defensive alliance (GA) [1] or a vertex alliance. If H = {K2}, then such an H-alliance we call an edge alliance [2]. In the case of H is a class of all complete graphs (i.e., K1, K2, . . .), then an H-alliance we call a complete alliance [3]. If H = {K1, . . . , Kk}, then an H-alliance we call k-complete alliance. In this talk we present general properties of global defensive secure structures (i.e., H-alliances), algorithms for H-alliance problems (exact and approximation ones), and we provide new N P-complete results for global defensive secure structures for bounded degree graphs. We formulate also H-alliance problem in some special cases as ILP problem and study a few algorithmic approaches.

  • Global Design Optimization of Microwave Circuits Using Response Feature Inverse Surrogates
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    • Leifur Leifsson
    2022

    Modern microwave design has become heavily reliant on full-wave electromagnetic (EM) simulation tools, which are necessary for accurate evaluation of microwave components. Consequently, it is also indispensable for their development, especially the adjustment of geometry parameters, oriented towards performance improvement. However, EM-driven optimization procedures incur considerable computational expenses, which may become impractical even in the case of local tuning, and prohibitive whenever global search is vital (e.g., multi-model tasks, simulation-based miniaturization, circuit re-design within extended ranges of operating frequencies). This work presents a novel approach to a computationally-efficient globalized parameter tuning of microwave components. Our framework employs the response feature technology, along with the inverse surrogate models. The latter permit low-cost exploration of the parameter space, and identification of the most advantageous regions that contain designs featuring performance parameters sufficiently close to the assumed target. The initial parameter vectors rendered in such a way undergo then local, gradient-based tuning. The incorporation of response features allows for constructing the inverse model using small training data sets due to simple (weakly-nonlinear) relationships between the operating parameters and dimensions of the circuit under design. Global optimization of the two microstrip components (a coupler and a power divider) is carried out for the sake of verification. The results demonstrate global search capability, excellent success rate, as well as remarkable efficiency with the average optimization cost of about a hundred of EM simulations of the circuit necessary to conclude the search process.

  • Global Surrogate Modeling by Neural Network-Based Model Uncertainty
    • Leifur Leifsson
    • Jethro Nagawkar
    • Laurel Barnet
    • Kenneth Bryden
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2022

    This work proposes a novel adaptive global surrogate modeling algorithm which uses two neural networks, one for prediction and the other for the model uncertainty. Specifically, the algorithm proceeds in cycles and adaptively enhances the neural network-based surrogate model by selecting the next sampling points guided by an auxiliary neural network approximation of the spatial error. The proposed algorithm is tested numerically on the one-dimensional Forrester function and the two-dimensional Branin function. The results demonstrate that global surrogate modeling using neural network-based function prediction can be guided efficiently and adaptively using a neural network approximation of the model uncertainty.