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Gdańsk University of Technology

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Publications from the year 2023

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  • NON-LOCAL VOLUMETRIC APPROACH TO ANALYSIS DEFECT'S SHAPE INFLUENCE ON SPECIMENS DURABILITY SUBJECTED TO BENDING AND TORSION
    • Zbigniew Marciniak
    • Ricardo Branco
    • Rui F. Martins
    • Wojciech Macek
    • Dariusz Rozumek
    2023 Full text INTERNATIONAL JOURNAL OF FATIGUE

    The influence of defect features on fatigue behaviour is a complex trivial issue. Although the important advances over the last decades, the dialectical relationship between the defect orientation and durability is not clearly understood. The paper aims at studying the influence of the orientation of elliptical defects on the durability of samples made of C45 steel. Three types of samples with elliptical defects were subjected to cyclic bending and torsion (R = -1) in the form of a one-sided notch oriented at various angles, namely 45, 60 and 90 degrees. The stress analysis was performed using local and non-local methods in order to determine an equivalent stress amplitude. The stress fields surrounding the defects were evaluated via three-dimensional numerical models. Then, the results were compared with the results obtained for smooth samples. The results show that the defect orientation has a higher effect under bending loading than under torsion and that the defects oriented perpendicularly to the longitudinal axis of the specimen are more detrimental.

  • Non-Nutritive Bioactive Compounds in Food of Plant Origin
    • Barbara Kusznierewicz
    2023

    The increasing knowledge on the health benefits of certain food ingredients, in particular, those of plant origin, opened the discussion of the possibility of using edible plants or their active components in the prevention of non-communicable diseases. The health-promoting properties of plant foods are related to the presence of non-nutritive compounds, mainly plant secondary metabolites, which can affect many biological mechanisms critical for the proper functioning of the human body. This chapter presents an overview of the most commonly consumed secondary metabolites found in the food, including phenolics, terpenoids, nitrogen/sulfur-containing compounds such as betalains, purine alkaloids, glucosinolates, and sulfoxides, along with their classification, examples, sources, processing effect, and health benefits.

  • Nonprotein nitrogenous compounds
    • Edyta Malinowska-Pańczyk
    2023

    The non-protein nitrogen (NPN) fraction is an important group of food components for both technological and nutritional reasons. Free amino acids (FAAs), oligopeptides, amines, nucleic acids, and nucleotides, as well as other low-molecular nitrogen-containing components (cyanogenic glycosides, alkaloids, thiazoles, oxazoles, pyrroles, and pyrazines), are found in most foods. Their content depends on many factors, starting from the condition of cultivation and breeding, through the method of obtaining, to the hygienic and storage conditions of raw material and finished product, as well as the applied processing technology. NPNs and the compounds formed during their transformation also create the sensory properties of food. Some of them, such as biogenic amines and nitrosamines, can be harmful to human health.

  • Nonstandard Equivalence Scales and their Applications for European Union Countries
    • Stanisław Maciej Kot
    2023

    The aim of this study is twofold. First, we propose new methods of estimating equivalence scales. We call these methods nonstandard to distinguish them from the standard procedures based on the microeconomic theory of demand systems. Searching for the ‘as simple as possible’ method has been a leitmotiv of this study. Second, we estimate various forms of equivalence scales for 28 European Union (EU) member countries and four non-member European countries from 2004 to 2018.

  • Non-toxic fluorine-doped TiO2 nanocrystals from TiOF2 for facet-dependent naproxen degradation
    • Marta Kowalkińska
    • Karol Sikora
    • Marcin Łapiński
    • Jakub Karczewski
    • Anna Zielińska-Jurek
    2023 Full text CATALYSIS TODAY

    In the present study, the photocatalytic degradation of naproxen (NPX), which is a nonsteroidal anti-inflammatory drug (NSAID), frequently detected in drinking water, was investigated. The F-doped TiO2 with defined morphology was successfully obtained from TiOF2 and applied for photocatalytic degradation under UV-vis and visible light. All samples were characterised by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, zeta potential, diffuse reflectance spectroscopy, and Brunauer–Emmett–Teller surface area analyses. The effect of morphology on the photocatalytic activity of the F-TiO2 nanostructures with exposed {1 0 1}, {0 0 1} and {1 0 0} facets was studied. Octahedral F-TiO2 particles with exposed {1 0 1} facets revealed the highest photocatalytic activity, and degraded 100% of the initial NPX concentration after 40 min of the photodegradation process under simulated solar light (UV-vis). Moreover, this sample exhibited the highest TOC removal and NPX degradation under visible light (>420 nm). Based on HPLC-MS analysis, it was assumed that {0 0 1} facets present in fluorinated decahedral nanostructures promote the formation of a dimer, which further hinders the mineralisation rate. Therefore, decahedral nanostructures exposing {1 0 1} and {0 0 1} facets revealed lower photocatalytic activity than octahedral F-TiO2 particles with exposed {1 0 1} facets, which is also consistent with DFT studies. Finally, toxicity assessment of post-process suspensions using Microtox bioassay confirmed that fluorine-doped octahedral anatase particles are non-toxic, although fluorine ions were the reactants of the synthesis from TiOF2. Overall results showed the possibility of application of highly efficient and environmentally safe fluorine-doped anatase photocatalysts in improved degradation of naproxen.

  • Non-uniqueness of fracture parameter choice in simulations of concrete cracking at mesoscale level
    • Beniamin Kondys
    • Jerzy Bobiński
    • Ireneusz Marzec
    2023 Full text ARCHIVES OF MECHANICS

    In the paper a non-uniqueness of fracture parameter choice in simulations of cracking process in plain concrete specimens at mesoscale level under monotonic static loading is analysed. The Finite Element Method is used, where cracks are defined in a discrete way using interface cohesive elements with nonlinear material law including softening. The concrete mesostructure (such as: cement matrix, air voids, aggregates, and Interfacial Transitions Zones (ITZ)) is taken into account. Two benchmarks: Montevideo splitting test (MVD) as a main test and the three-point beam bending test (TPBT) as an auxiliary problem are simulated. Results from 2D calculations are compared with experimental outcomes, especially force-crack opening curves and crack patterns are carefully studied. In the MVD test, the mesostructure of a specimen is taken from X-ray micro-computed tomography scans of real samples. The issue of the proper selection of material parameters for cohesive cracks is investigated. The ambiguity of such a process is presented and discussed. It turns out the numerical simulations can give the same outcome for different values of material parameters. The influence of the selected material parameters and the friction coefficient on results (force–crack opening curves and crack patterns) is also analysed.

  • Novel 2-alkythio-4-chloro-N-[imino(heteroaryl)methyl]benzenesulfonamide Derivatives: Synthesis, Molecular Structure, Anticancer Activity and Metabolic Stability
    • Beata Żołnowska
    • Jarosław Sławiński
    • Mariusz Belka
    • Tomasz Baczek
    • Jarosław Chojnacki
    • Anna Kawiak
    2023 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    A series of novel 2-alkythio-4-chloro-N-[imino-(heteroaryl)methyl]benzenesulfonamide derivatives, 8–24, were synthesized in the reaction of the N-(benzenesulfonyl)cyanamide potassium salts 1–7 with the appropriate mercaptoheterocycles. All the synthesized compounds were evaluated for their anticancer activity in HeLa, HCT-116 and MCF-7 cell lines. The most promising compounds, 11–13, molecular hybrids containing benzenesulfonamide and imidazole moieties, selectively showed a high cytotoxic effect in HeLa cancer cells (IC50: 6–7 uM) and exhibited about three times less cytotoxicity against the non-tumor cell line HaCaT cells (IC50: 18–20 uM). It was found that the anti-proliferative effects of 11, 12 and 13 were associated with their ability to induce apoptosis in HeLa cells. The compounds increased the early apoptotic population of cells, elevated the percentage of cells in the sub-G1 phase of the cell cycle and induced apoptosis through caspase activation in HeLa cells. For the most active compounds, susceptibility to undergo first-phase oxidation reactions in human liver microsomes was assessed. The results of the in vitro metabolic stability experiments indicated values of the factor t12 for 11–13 in the range of 9.1–20.3 min and suggested the hypothetical oxidation of these compounds to sulfenic and subsequently sulfinic acids as metabolites.

  • Novel Investigation of Higher Order Spectral Technologies for Fault Diagnosis of Motor-Based Rotating Machinery
    • Tomasz Ciszewski
    • Len Gelman
    • Andrew Ball
    • Abdulmumeen Onimisi Abdullahi
    • Biebele Jamabo
    • Michał Ziółko
    2023 Full text SENSORS

    In the last decade, research centered around the fault diagnosis of rotating machinery using non-contact techniques has been significantly on the rise. For the first time worldwide, innovative techniques for the diagnosis of rotating machinery, based on electrical motors, including generic, nonlinear, higher-order cross-correlations of spectral moduli of the third and fourth order (CCSM3 and CCSM4, respectively), have been comprehensively validated by modeling and experiments. The existing higher-order cross-correlations of complex spectra are not sufficiently effective for the fault diagnosis of rotating machinery. The novel technology CCSM3 was comprehensively experimentally validated for induction motor bearing diagnosis via motor current signals. Experimental results, provided by the validated technology, confirmed high overall probabilities of correct diagnosis for bearings at early stages of damage development. The novel diagnosis technologies were compared with existing diagnosis technologies, based on triple and fourth cross-correlations of the complex spectra. The comprehensive validation and comparison of the novel cross-correlation technologies confirmed an important non-traditional novel outcome: the technologies based on cross-correlations of spectral moduli were more effective for damage diagnosis than the technologies based on crosscorrelations of the complex spectra. Experimental and simulation validations confirmed a high probability of correct diagnosis via the CCSM at the early stage of fault development. The average total probability of incorrect diagnosis for the CCSM3 for all experimental results of 8 tested bearings, estimated via 6528 diagnostic features, was 1.475%. The effectiveness gains in the total probability of incorrect diagnosis for the CCSM3 in comparison with the CCCS3 were 26.8 for the experimental validation and 18.9 for the simulation validation. The effectiveness gains in the Fisher criterion for the CCSM3 in comparison with the CCCS3 were 50.7 for the simulation validation and 104.7 for the experimental validation.

  • Novel sugar-based nickel-tungsten carbide catalysts for dry reforming of hydrocarbons
    • Izabela Wysocka
    • Natalia Czaplicka
    • Ewelina Pawelczyk
    • Jakub Karczewski
    • Joanna Sobczak
    • Zuzanna Bielan
    • Michał Maciejewski
    • Barbara Kościelska
    • Andrzej Rogala
    2023 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY

    The search for new materials for dry reforming of hydrocarbons with high activity, stability, and ease of synthesis is still one of the main directions of research in the field of heterogeneous catalysis. Traditional methods of carbide synthesis require the use of combustible gases of petrochemical origin. The search for new catalysts based on renewable and safe carbon sources is highly demanded. Therefore, we report WC and Ni-WC catalysts prepared using glucose, sucrose, fructose and trehalose. The materials were characterized using XRD, AAS, H2-TPR, SEM, TEM, Raman spectroscopy, FTIR, CO2- TPD, TG/DTG BET and BJH methods. The catalytic activity was investigated in the dry reforming of methane and plastics. The sugar type used for the preparation determined crystal structure and therefore catalytic properties of Ni-WC catalysts. The most active and stable catalyst was prepared using sucrose. It was observed that catalysts obtained with the use of sugars containing fructose in their structure are characterized by smaller WC and Ni crystallites, which have a direct impact on high catalytic activity. The catalytic activity of the most active catalyst Ni-WC_S was examined in the dry reforming of plastics.The highest syngas generation was observed for low-density polyethylene reforming reaching 75.58 mmol/g plastic.

  • Novel Tools for Comprehensive Functional Analysis of LDLR (Low-Density Lipoprotein Receptor) Variants
    • Jacek Jasiecki
    • Monika Targońska
    • Anna Janaszak-Jasiecka
    • Magdalena Chmara
    • Monika Żuk
    • Leszek Kalinowski
    • Krzysztof Waleron
    • Bartosz Wasąg
    2023 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Familial hypercholesterolemia (FH) is an autosomal-dominant disorder caused mainly by substitutions in the low-density lipoprotein receptor (LDLR) gene, leading to an increased risk of premature cardiovascular diseases. Tremendous advances in sequencing techniques have resulted in the discovery of more than 3000 variants of the LDLR gene, but not all of them are clinically relevant. Therefore, functional studies of selected variants are needed for their proper classification. Here, a single-cell, kinetic, fluorescent LDL uptake assay was applied for the functional analysis of LDLR variants in a model of an LDLR-deficient human cell line. An LDLR-defective HEK293T cell line was established via a CRISPR/Cas9-mediated luciferase–puromycin knock-in. The expressing vector with the LDLR gene under the control of the regulated promoter and with a reporter gene has been designed to overproduce LDLR variants in the host cell. Moreover, an LDLR promoter–luciferase knock-in reporter system has been created in the human cell line to study transcriptional regulation of the LDLR gene, which can serve as a simple tool for screening and testing new HMG CoA reductase-inhibiting drugs for atherosclerosis therapy. The data presented here demonstrate that the obtained LDLR-deficient human cell line HEK293T-ldlrG1 and the dedicated pTetRedLDLRwt expression vector are valuable tools for studying LDL internalization and functional analysis of LDLR and its genetic variants. Using appropriate equipment, LDL uptake to a single cell can be measured in real time. Moreover, the luciferase gene knock-in downstream of the LDLR promotor allows the study of promoter regulation in response to diverse conditions or drugs. An analysis of four known LDLR variants previously classified as pathogenic and benign was performed to validate the LDLR-expressing system described herein with the dedicated LDLR-deficient human cell line, HEK293T-ldlrG1.

  • Novel Versatile Topologies and Design Optimization of Wide-Bandstop Frequency Selective Surfaces for X-Band, Ku-Band and Millimeter-Wave Applications
    • Rao Aziz
    • Sławomir Kozieł
    • Leifur Leifsson
    • Stanisław Szczepański
    2023 Full text Scientific Reports

    Novel designs of frequency selective surface (FSS) are presented for wideband applications in X, Ku and mmWave (millimeter Wave) bands. Two identical metallic layers of FSS are imprinted on both sides of the RO4003 substrate. The geometry parameters are optimized to maximize the bandstop at the specified in-band maximum transmission level of –10 dB; satisfaction of the latter condition is enforced through appropriate formulation and handling of the design constraints. The proposed structure is versatile and can be readily re-designed for various operating bands. For the sake of illustration, two instances of the FSS were developed. Design 1 exhibits broad bandstop of 9.8 GHz at the X- and Ku-bands, whereas the bandstop of Design 2 is 33.5 GHz at the mmWave band. The two FSS unit cell designs share the same base topology, but specific dimensions are adjusted to operate within the lower and the higher bands, respectively. The unit cell is symmetrical, therefore, ensures an excellent resonance stability performance with respect to different polarizations (TE and TM) and incidence angles. For proof of concept only FSS Design 1 is fabricated and measured in an anechoic chamber. The simulated and measured results exhibit good agreement. Extensive benchmarking against state-of-the-art FSS designs from the literature corroborates the advantages of the proposed topology in terms of design novelty, topological versatility, compact size, and wide bandstop response as compared to the previously available designs.

  • Nowe protokoły transportowe w sieciach IP. Analiza porównawcza wybranych mechanizmów w protokołach SCTP i QUIC
    • Józef Woźniak
    2023 Full text Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Zestaw protokolarny TCP/IP opisuje podstawową koncepcję organizacji pracy Internetu. Z tej racji jest przedmiotem zainteresowania oraz stałych analiz zarówno operatorów, użytkowników, jak też badaczy zagadnień sieciowych, a wreszcie i projektantów, by reagować na pojawiające się nowe potrzeby. Działania takie, przynajmniej częściowo, są wymuszane zarówno przez wymagania nowych multimedialnych aplikacji - na najwyższym poziomie architektury sieciowej, jak też zupełnie nowe możliwości realizacji przekazów - związane z nowymi technologiami transmisyjnymi i technikami odbioru, pozwalającymi, przykładowo na zrównoleglenie przekazów, czy też bezstratne przełączanie pomiędzy kilkoma interfejsami. W artykule pokrótce zasygnalizowano oczekiwania i wymagania związane, w szczególności z nowymi „wielobiektowymi” aplikacjami, jak też ograniczenia wynikające z ogromnej bezwładności, obserwowanej po stronie infrastruktury transportowej sieci IP. Mając na uwadze wspomniane uwarunkowania dokonano charakterystyki wybranych protokołów transportowych typu end-to-end, poświęcając główną uwagę dwóm protokołom realizującym przekazy wielostrumieniowe, a mianowicie SCTP oraz QUIC. Zaprezentowano zarówno wykorzystywane w obu protokołach struktury danych, jak też porównano podstawowe procedury związane z ich pracą. Dokonano też zestawienia cech charakterystycznych obu protokołów, wskazując na zakres ich użyteczności oraz scenariusze użycia.

  • Nowe wyzwania, nowe rozwiązania. Jak przedsiębiorstwo branży IT odnajduje się w erze VUCA?
    • Jakub Majewski
    • Krzysztof Leja
    2023 Full text e-mentor

    Zmienność, niepewność, złożoność i niejednoznaczność, określane akronimem VUCA (volatility, uncertainty, complexity, ambiguity) towarzyszą funkcjonowaniu każdego przedsiębiorstwa. Jak wykorzystać te nieodłączne cechy otoczenia przedsiębiorstw jako szanse dla ich rozwoju to wy-zwania stojące przed nimi, a zarazem pytanie badawcze artykułu. Celem artykułu jest wykazanie, na przykładzie przedsiębiorstwa branży IT, że analiza zmienności, niepewności, złożoności i nie-jednoznaczności pozwala na zidentyfikowanie kompetencji niezbędnych, aby zagrożenia wykorzystać jako szansę doskonalenia przedsiębiorstwa. Artykuł został opracowany w ujęciu jakościowym. Składają się na nie obserwacja uczestnicząca jednego z Autorów z wykorzystaniem narzędzi umożliwiających diagnozę badanego przedsiębiorstwa z perspektywy cech określanych akronimem VUCA oraz ocena kompetencji, które pozwolą zagrożenia wykorzystać jako szanse. Punktem wyjścia diagnozy jest zwięzły przegląd literatury światowej dotyczącej organizacji w erze VUCA. Podjęta problematyka jest zdaniem Autorów ważna dla przedsiębiorstw różnych branż, dlatego wykorzystane w artykule metody i narzędzia badawcze mogą być pomocne także do diagnozy innych firm, jednak wyniki obecnych analiz nie uprawniają do uogólnień.

  • Nowy algorytm rozszerzania bazy w arytmetyce resztowej
    • Robert Smyk
    • Maciej Czyżak
    2023 Full text

    W artykule przedstawiono nowy algorytm rozszerzania bazy w resztowym systemie liczbowym bez użycia nadmiarowego modułu. Rozszerzanie bazy jest kluczową operacją w wielu zastosowaniach, gdzie używany jest resztowy system liczbowy, takich jak cyfrowe przetwarzanie sygnałów, jak też implementacja systemu szyfrowania algorytmem Rivesta-Shamira-Adlemana (RSA). Ortogonalne projekcje występujące w chińskim twierdzeniu o resztach, dla modułu, o który jest rozszerzana baza systemu resztowego, przechowywane są w niewielkich pamięciach typu ROM (ang. Read-Only Memory) w formie resztowej. Projekcje te są sumowane w sumatorze binarnym i otrzymana suma jest redukowana dla modułu, o który rozszerzana jest baza. Metoda wykorzystuje nowy i efektywny algorytm obliczania współczynnika nadmiaru w chińskim twierdzeniu o resztach. Metoda umożliwia wielokrotną redukcję złożoności sprzętowej.

  • Numerical Analysis of Seismic Pounding between Adjacent Buildings Accounting for SSI
    • Mehmet Eren Uz
    • Anna Jakubczyk-Gałczyńska
    • Robert Jankowski
    2023 Full text Applied Sciences-Basel

    The structural pounding caused by an earthquake may damage structures and lead to their collapse. This study is focused on the pounding between two adjacent asymmetric structures with different dynamic properties resting on the surface of an elastic half-space. An exploration of the relationship between the effects of the seismic analysis with the impact response to the torsional pounding between adjacent buildings under different SSI effects has been presented. In this paper, the authors have proposed a procedure for analyzing the response for adjacent buildings subjected to the pounding effects, considering systems with multiple degrees of freedom and modal equations of motion with four types of soil. All the calculations have been performed based on the fourth-order Runge–Kutta method. The novelty of the present study is related to the fact that the rigorous and approximate methods are used to examine the effects of pounding and SSI simultaneously. As a result, these two methods have been thoroughly investigated for both effects and the results have been compared. The results show that the approximate method produces results that are slightly different from those obtained by the rigorous direct integration method in the case of small SSI effects due to an increase in the pounding force. The efficiency of the method is also validated using numerical examples.

  • Numerical analysis of the ostiomeatal complex aeration using the CFD method
    • Dmitry Tretiakow
    • Krzysztof Tesch
    • Karolina Markiet
    • Tomasz Przewoźny
    • Aida Kusiak
    • Dominika Cichońska
    • Andrzej Skorek
    2023 Full text Scientific Reports

    We aimed to analyse ostiomeatal complex (OMC) aeration using the computational fluid dynamics (CFD) method of simulation based on human craniofacial computed tomography (CT) scans. The analysis was based on CT images of 2 patients: one with normal nose anatomy and one with nasal septal deviation (NSD). The Reynolds-Average Simulation approach and turbulence model based on linear eddy viscosity supplemented with the two-equation k- ω SST model were used for the CFD simulation. As a result, we found differences in airflow velocity through the ostiomeatal complex in patients with a normal nose and those with NSD. In a patient with NSD, the flow is turbulent in contrast to the normal nose (laminar flow). A faster (more intensive) airflow through the OMC was observed in the wider nasal cavity of the patient with NSD than on the narrower side. In addition, we want to emphasise the higher speed of airflow through the apex uncinate process area towards the ostiomeatal complex during exhalation, which, in the presence of secretions in the nose, predisposes to its easier penetration into the sinuses of the anterior group.

  • Numerical Analysis of Turbulent Flow over a Backward-facing Step in an Open Channel
    • Bala Kawa M. Saleem
    • Andam Mustafa
    • Dalshad Ahmed Kareem
    • Mehmet Ishak Yüce
    • Michał Szydłowski
    2023 Full text Archives of Hydro-Engineering and Environmental Mechanics

    Computational examinations of the flow field in an open channel having a single Backward--Facing Step (BFS) with a constant water depth of 1.5 m were performed. The effects of the expansion ratio, and the flow velocity along the reattachment length, were investigated by employing two different expansion ratios of 1.5 and 2, and eight various flow velocities of 0.5, 1, 2, 3, 4, 5, 7.5 and 10 m/sec in the Computational Fluid Dynamic (CFD) simulations. Commercially available CFD software, ANSYS FLUENT, was used for calculations. The simulation outcomes were verified using experimental results. Moreover, analyses were performed by using two equation turbulence closure models, K-ε family (standard, RNG and realizable), and K-ω family (Wilcox’s and SST K-ω). The analyses have revealed that the reattachment length increases with an increase in the expansion ratio, the flow velocity and the Reynolds number. The results obtained for two expansion rates and eight different flow velocities have shown insignificant differences between one turbulence closure model and the others. Furthermore, it was observed that both velocity and expansion ratios have an effect on the reattachment zone size.

  • Numerical and Clinical Analysis of an Eyeball Injuries under Direc Impact
    • Mateusz Koberda
    • Andrzej Skorek
    • Paweł Kłosowski
    • Marcin Zmuda Trzebiatowski
    • Krzysztof Żerdzicki
    • Paweł Lemski
    • Urszula Stodolska-Koberda
    2023 Full text International Journal of Occupational Medicine and Environmental Health

    Objectives: The objective of this study was to develop a numerical model of the eyeball and orbit to simulate a blunt injury to the eyeball leading to its rupture, as well as to conduct a comparative analysis of the results obtained using the finite element method against the clinical material concerning patients who had suffered an eyeball rupture due to a blunt force trauma. Material and Methods: Using available sclera biometric and strength data, a numerical model of the eyeball, the orbital contents, and the bony walls were developed from the ground up. Then, 8 different blunt force injury scenarios were simulated. The results of numerical analyses made it possible to identify possible locations and configurations of scleral rupture. The obtained results were compared against the clinical picture of patients hospitalized at the Department of Ophtalmology, Medical University of Gdańsk in 2010–2016 due to isolated blunt force trauma to the eyeball. Results: It has been demonstrated that the extent of damage observed on the numerical model that indicated a possible location of eyeball rupture did not differ from the clinically observed configurations of the scleral injuries. It has been found that the direction of the impact applied determines the location of eyeball rupture. Most often the rupture occurs at the point opposite to the clock-hour/positions of the impact application. The eyeball rupture occurs in the first 7–8 ms after the contact with the striking rigid object. It has been established that the injuries most often affected the upper sectors of the eyeball. Men are definitely more likely to sustain such injuries. Eyeball ruptures lead to significant impairment of visual acuity. Conclusions: This study may contribute to a better understanding of injury mechanisms and better treatment planning. It may also contribute to the development of eyeball protection methods for employees exposed to ocular injuries.

  • Numerical and experimental investigation of guided ultrasonic wave propagation in non-uniform plates with structural phase variations
    • Beata Zima
    • Jochen Moll
    2023 Full text ULTRASONICS

    The article presents the results of numerical and experimental investigations of guided wave propagation in aluminum plates with variable thickness. The shapes of plate surfaces have been specially designed and manufactured using a CNC milling machine. The shapes of the plates were defined by sinusoidal functions varying in phase shift, which forced the changes in thickness variability alongside the propagation path. The main aim of the study is to analyze the wave propagation characteristics caused by non-uniform thickness. In the first step, the influence of thickness variability on the time course of propagating waves has been analyzed theoretically. The study proves that the wave propagation signals can be determined based on knowledge about the statistical description of the specimen geometry. The histograms of thickness distribution together with the a priori knowledge of the dispersion curves were used to develop an iterative procedure assuming that the signal from the previous step becomes the excitation in the next step. Such an approach allowed for taking into account the complex geometry of the plate and rejecting the assumption about the constant average thickness alongside the propagation path. In consequence, it was possible to predict correctly the signal time course, as well as the time of flight and number of propagating wave modes in specimens with variable thickness. It is demonstrated that theoretical signals predicted in this way coincide well with numerical and experimental results. Moreover, the novel procedure allowed for the correct prediction of the occurrence of higher-order modes.

  • Numerical and quantitative analysis of HIV/AIDS model with modified Atangana-Baleanu in Caputo sense derivative
    • Muhammad Farman
    • Saba Jamil
    • Muhammad Riaz
    • Muhammad Azeem
    • Muhammad Umer Saleem
    2023 Full text Alexandria Engineering Journal

    Fractional calculus plays an important role in the development of control strategies, the study of the dynamical transmission of diseases, and some other real-life problems nowadays. The time-fractional HIV/AIDS model is examined using a novel method in this paper. Based on the Atangana-concept Baleanu’s of a derivative in the Caputo sense, the current modified fractional derivative operator uses singular and non-local kernels. This new modified fractional operator is given a numerical approximation and applied to the HIV/AIDS model. In the presence of this novel operator, we present some significant analysis for the HIV/AIDS epidemic model. The uniqueness and stability criteria of the model have been demonstrated using the Picard successive approxima- tion approach and Banach’s fixed point theory. The Laplace Adomian decomposition method (LADM) was used to obtain the numerical solution for the modified Atangana-Baleanu Caputo derivative model. The convergence analysis is verified for the proposed scheme. Finally, numerical results and simulations are derived with the proposed scheme for HIV/AIDS model. On the dynam- ics of HIV/AIDS transmission, the effects of many biological parameters are examined