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  • On the Importance of Resilience Engineering for Networked Systems in a Changing World
    • David Hutchison
    • Dimitrios Pezaros
    • Jacek Rak
    • Paul Smith
    2023 Pełny tekst IEEE COMMUNICATIONS MAGAZINE

    Resilience is featured increasingly often in the media, usually applied to society when faced, for example, with disasters such as flooding and the enormous challenges that the Covid-19 pandemic posed. There are now many resilience-related discussion groups worldwide, and some standards initiatives devoted in particular to city resilience. However, there is relatively little explicit interest in resilience engineering for communication networks and systems, including the Internet. This is perhaps surprising, given the reliance that society now places on networks and networked systems. This article reflects on key issues and developments that may change this perspective; we summarize recent and current research in resilient systems and, consequently, propose a multidisciplinary research agenda in resilience engineering for networked systems.

  • On the Possibility of Increasing Ship Energy Efficiency Through Improved Propulsion Control System
    • Mohammad Ghaemi
    2023

    This paper summarizes the analyses conducted to assess the impact of the ship's propulsion control system on energy efficiency in calm, manoeuvre, and sea wave conditions, where the goal of the investigation is to develop new strategies for controlling the ship's motion while considering the interactions between the hull, engine, and propeller.

  • On the use of leading safety indicators in maritime and their feasibility for Maritime Autonomous Surface Ships
    • Krzysztof Wróbel
    • Mateusz Gil
    • Przemysław Krata
    • Karol Olszewski
    • Jakub Montewka
    2023 Proceedings of the Institution of Mechanical Engineers Part O-Journal of Risk and Reliability

    Although the safety of prospective Maritime Autonomous Surface Ships will largely depend on their ability to detect potential hazards and react to them, the contemporary scientific literature lacks the analysis of how to achieve this. This could be achieved through an application of leading safety indicators. The aim of the performed study was to identify the research directions of leading safety indicators in three safety-critical operational aspects of Maritime Autonomous Surface Ships: collision avoidance, intact stability, and communication. To achieve this, literature review is performed, taking into account scientific documents including journal and conference papers. The results indicate that the need for establishing operational leading safety indicators is recognized by numerous scholars, who sometimes make suggestions of what the set of indicators shall consist of. Some leading safety indicators for autonomous vessels are readily identifiable in the scientific literature and used in current practice. However, the research effort is lacking a holistic approach to the issue.

  • On time-dependent nonlinear dynamic response of micro-elastic solids
    • Mohammad Malikan
    • Victor Eremeev
    2023 INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE

    A new approach to the mechanical response of micro-mechanic problems is presented using the modified couple stress theory. This model captured micro-turns due to micro-particles' rotations which could be essential for microstructural materials and/or at small scales. In a micro media based on the small rotations, sub-particles can also turn except the whole domain rotation. However, this framework is competent for a static medium. In terms of dynamic investigations of micro materials, it is required to involve micro-rotations' mass inertias. This fact persuades us to pay particular attention to the micro mechanics' samples and directed us to re-derive the modified couple stress model to propose and represent a new micro-mechanic approach which is well-deserved, especially for dynamic studies of microstructures. In carrying out this job, the classical beam has provided the basic form of formulation procedure. The continuum medium has been limited to a square flat non-porous beam deducing a homogeneous isotropic micromaterial. As long as the time-dependent results are concerned due to studying micro-mass inertia in time history, there would be two solution steps. The Galerkin decomposition technique is imposed in accord with an analytical postulate to issue the algebraic problem distributing time-dependent equations. The latter, the Homotopy perturbation method delivers time-dependent outcomes. The solution methods have been validated by building numerical models in Abaqus software. On the new achievements of this study, one can declare that both static and dynamic length scale parameters are very effective in order to study vibrations of microstructures. If the values of these characteristic lengths are considerable, the nonlinear frequency analysis will be essential.Furthermore, the stiffness of the structure will be higher if the values of both length scale parameters increase.

  • On Unsupervised Artificial-Intelligence-Assisted Design of Antennas for High-Performance Planar Devices
    • Sławomir Kozieł
    • Weiping Dou
    • Peter Renner
    • Andrew Cohen
    • Yuandong Tian
    • Jiang Zhu
    • Anna Pietrenko-Dąbrowska
    2023 Pełny tekst Electronics

    Design of modern antenna structures is a challenging endeavor. It is laborious, and heavily reliant on engineering insight and experience, especially at the initial stages oriented towards the devel-opment of a suitable antenna architecture. Due to its interactive nature and hands-on procedures (mainly parametric studies) for validating suitability of particular geometric setups, typical antenna development requires many weeks and significant involvement of a human expert. The same reasons only allow the designer to try out a very limited number of options in terms of antenna geometry arrangements. Automated topology development and dimension sizing is therefore of high interest, especially from industry perspective where time-to-market and expert-related ex-penses are of paramount importance. This paper discusses a novel approach to unsupervised specification-driven design of planar antennas. The presented methodology capitalizes on a flexi-ble and scalable antenna parameterization, which enables realization of complex geometries while maintaining reasonably small parameter space dimensionality. A customized nature-inspired al-gorithm is employed to carry out space exploration and identification of a quasi-optimum antenna topology in a global sense. A fast gradient-based procedure is then incorporated to fine tune an-tenna dimensions. The design framework works entirely in a black-box fashion with the only in-put being design specifications, and optional constraints, e.g., concerning the structure size. Nu-merous illustration case studies demonstrate the capability of the presented technique to generate unconventional antenna topologies of satisfactory performance using reasonable computational budgets, and with no human expert interaction necessary whatsoever.

  • On well-posedness of the first boundary-value problem within linear isotropic Toupin–Mindlin strain gradient elasticity and constraints for elastic moduli
    • Victor Eremeev
    2023 Pełny tekst ZAMM-Zeitschrift fur Angewandte Mathematik und Mechanik

    Within the linear Toupin–Mindlin strain gradient elasticity we discuss the well-posedness of the first boundary-value problem, that is, a boundary-value problem with Dirichlet-type boundary conditions on the whole boundary. For an isotropic material we formulate the necessary and sufficient conditions which guarantee existence and uniqueness of a weak solution. These conditions include strong ellipticity written in terms of higher-order elastic moduli and two inequalities for the Lamé moduli. The conditions are less restrictive than those followed from the positive definiteness of the deformation energy.

  • One More Step Towards a Circular Economy for Thermal Insulation Materials—Development of Composites Highly Filled with Waste Polyurethane (PU) Foam for Potential Use in the Building Industry
    • Łukasz Kowalczyk
    • Jerzy Korol
    • Błażej Chmielnicki
    • Aleksandra Laska
    • Daniel Chuchała
    • Aleksander Hejna
    2023 Pełny tekst Materials

    The rapid development of the building sector has created increased demand for novel materials and technologies, while on the other hand resulting in the generation of a severe amount of waste materials. Among these are polyurethane (PU) foams, which are commonly applied as thermal insulation materials. Their management is a serious industrial problem, due to, for example, their complex chemical composition. Although some chemical and thermochemical methods of PU foam recycling are known, their broader use is limited due to requirements related to the complexity and safety of their installation, thus implicating high costs. Therefore, material recycling poses a promising alternative. The incorporation of waste PU foams as fillers for polymer composites could make it possible to take advantage of their structure and performance. Herein, polypropylene-based composites that were highly filled with waste PU foam and modified using foaming agents were prepared and analyzed. Depending on the foam loading and the foaming agent applied, the apparent density of material was reduced by as much as 68%. The efficient development of a porous structure, confirmed by scanning electron microscopy and high-resolution computed micro-tomography, enabled a 64% decrease in the thermal conductivity coefficient. The foaming of the structure affected the mechanical performance of composites, resulting in a deterioration of their tensile and compressive performance. Therefore, developing samples of the analyzed composites with the desired performance would require identifying the proper balance between mechanical strength and economic, as well as ecological (share of waste material in composite, apparent density of material), considerations.

  • Ongoing Progress on Pervaporation Membranes for Ethanol Separation
    • Muhammad Imad
    • Roberto Castro Munoz
    2023 Pełny tekst Membranes

    Ethanol, a versatile chemical extensively employed in several fields, including fuel production, food and beverage, pharmaceutical and healthcare industries, and chemical manufacturing, continues to witness expanding applications. Consequently, there is an ongoing need for cost-effective and environmentally friendly purification technologies for this organic compound in both diluted (ethanol-water–) and concentrated solutions (water-ethanol–). Pervaporation (PV), as a membrane technology, has emerged as a promising solution offering significant reductions in energy and resource consumption during the production of high-purity components. This review aims to provide a panorama of the recent advancements in materials adapted into PV membranes, encompassing polymeric membranes (and possible blending), inorganic membranes, mixed-matrix membranes, and emerging two-dimensional-material membranes. Among these membrane materials, we discuss the ones providing the most relevant performance in separating ethanol from the liquid systems of water–ethanol and ethanol–water, among others. Furthermore, this review identifies the challenges and future opportunities in material design and fabrication techniques, and the establishment of structure–performance relationships. These endeavors aim to propel the development of next-generation pervaporation membranes with an enhanced separation efficiency.

  • Ontological Modeling for Contextual Data Describing Signals Obtained from Electrodermal Activity for Emotion Recognition and Analysis
    • Teresa Zawadzka
    • Tomasz Wierciński
    • Wojciech Waloszek
    • Michał Wróbel
    2023 Pełny tekst IEEE Access

    Most of the research in the field of emotion recognition is based on datasets that contain data obtained during affective computing experiments. However, each dataset is described by different metadata, stored in various structures and formats. This research can be counted among those whose aim is to provide a structural and semantic pattern for affective computing datasets, which is an important step to solve the problem of data reuse and integration in this domain. In our previous work, the ROAD ontology was introduced. This ontology was designed as a skeleton for expressing contextual data describing time series obtained in various ways from various signals and was focused on common contextual data, independent of specific signals. The aim of the presented research is to provide a carefully curated vocabulary for describing signals obtained from electrodermal activity, a very important subdomain of emotion analysis. We decided to present it as an extension to the ROAD ontology in order to offer means of sharing metadata for datasets in a unified and precise way. To meet this aim, the research methodology was defined, mostly focusing on requirements specification and integration with other existing ontologies. Application of this methodology resulted firstly in sharing the requirements to allow a broader discussion and secondly development of the EDA extension of the ROAD ontology, validated against the MAHNOB-HCI dataset. Both these results are very important with respect to the vast context of the work, i.e. providing an extendable framework for describing affective computing experiments. Introducing the methodology also opens the way for providing new extensions systematically just by executing the steps defined in the methodology.

  • Opinia dotycząca zasadności wykonanych robót hydrotechnicznych i sposobu zagospodarowania nieruchomości w kontekście wykorzystania jako morski port przeładunkowy.
    • Marcin Cudny
    • Mariusz Wyroślak
    2023

    Opinię przygotowano na podstawie umowy zawartej w Gdyni w dniu 2 lutego 2023r. pomiędzy Gdynia Container Terminal Sp. z o.o. z siedzibą w Gdyni przy ul. Energetyków 5 oraz Politechniką Gdańską z siedzibą w Gdańsku ul. Narutowicza 11/12.

  • Opinia geotechniczna dotycząca analizy przyczyn powstania nadmiernych osiadań podłogi obiektu magazynowego zlokalizowanego przy ul. Hutniczej 48 w Gdyni.
    • Rafał Ossowski
    • Mariusz Wyroślak
    • Waldemar Magda
    2023

    Opinię przygotowano na podstawie umowy nr 13/2023 zawartej w Gdyni w dniu 17 lipca 2023 r. pomiędzy Highgate Sp. z o.o. z siedzibą w Warszawie przy ul. Sienna 73 oraz Politechniką Gdańską z siedzibą w Gdańsku ul. Narutowicza 11/12. Nr archiwalny umowy WILiŚ/16/BZ/002/2023.

  • Opinia naukowo-techniczna dotycząca wyników badań statycznych i dynamicznych nośności pali prefabrykowanych wbijanych o wym. 40×40 cm podpór obiektów mostowych na budowie drogi ekspresowej S61, Ostrów Mazowiecka – Szczuczyn
    • Adam Krasiński
    • Andrzej Słabek
    2023

    Opiniowanie wyników badań nośności pali

  • Opinia techniczna dotycząca oceny przeprowadzonych robót ziemnych oraz przyjętych rozwiązań geotechnicznych w projekcie budowlanym w kontekście wpływu na podłoże gruntowe i obiekt budowlany działki sąsiedniej.
    • Mariusz Wyroślak
    2023

    Celem opinii jest ocena wpływu robót ziemnych wykonywanych na działce nr 396 obręb 0019 położonej w Gdyni Małym Kacku, przy ul. Radomskiej 21, na pogorszenie stanu gruntu i możliwość wystąpienia awarii budynku położonego na działce nr 395 obręb 0019 w Gdyni Małym Kacku przy ul. Radomskiej 19. Opinia odnosi się również do rozwiązań geotechnicznych zawartych w projekcie budowlanym, które mogły mieć wpływ na zaistnienie sytuacji awaryjnych obiektów wokół zaprojektowanego budynku.

  • Optical method supported by machine learning for urinary tract infection detection and urosepsis risk assessment
    • Paweł Wityk
    • Patryk Sokołowski
    • Małgorzata Szczerska
    • Kacper Cierpiak
    • Beata Krawczyk
    • Michał Markuszewski
    2023 Pełny tekst Journal of Biophotonics

    The study presents an optical method supported by machine learning for discriminating urinary tract infections from an infection capable of causing urosepsis. The method comprises spectra of spectroscopy measurement of artificial urine samples with bacteria from solid cultures of clinical E. coli strains. To provide a reliable classification of results assistance of 27 algorithms was tested. We proved that is possible to obtain up to 97% accuracy of the measurement method with the use of use of machine learning. The method was validated on urine samples from 241 patients. The advantages of the proposed solution are the simplicity of the sensor, mobility, versatility, and low cost of the test.

  • Optical rotation in the lithium triborate nonlinear crystal
    • Mykola Shopa
    • Nazar Ftomyn
    • Yaroslav Shopa
    2023 Journal of Applied Crystallography

    A dual-wavelength polarimetric technique at 633 and 661 nm has been used for the characterization of a nonlinear lithium triborate (LiB3O5) nonenantiomorphous biaxial crystal. The mismatch of the crystallographic and optical coordinate systems was taken into account. The optical rotatory power for light propagation along one of the optical axes is ρ = 7.06° mm−1. The gyration tensor component along the bisector between the x and y crystallographic axes has been measured as g12 = 4.31 × 10−5. Computed values based on the crystalline structure and electronic polarizabilities are in good agreement with those obtained experimentally.

  • Optimal Design of Transmitarray Antennas via Low-Cost Surrogate Modelling
    • Mehmet Belen
    • Alper Caliskan
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Peyman Mahouti
    2023 Pełny tekst Scientific Reports

    Over the recent years, reflectarrays and transmitarrays have been drawing a considerable attention due to their attractive features, including a possibility of realizing high gain and pencil-like radiation patterns without the employment of complex feeding networks. Among the two, transmitarrays seem to be superior over reflectarrays in terms of achieving high radiation efficiency without the feed blockage. Notwithstanding, the design process of transmitarrays is more intricate due to the necessity of manipulating both the transmission phase and magnitude of its unit elements. For reliability, the design process has to be conducted at the level of full-wave electromagnetic (EM) models, which makes direct optimization prohibitive. The most widely used workaround is to employ surrogate modeling techniques to construct fast representations of the unit elements, yet the initial model setup cost is typically high and includes acquisition of thousands of training data points. In this paper, we propose a novel approach to cost-efficient design of transmitarrays. It is based on artificial-intelligence (AI)-enabled data-driven surrogates, which can be constructed using only a few hundreds of training data samples, while exhibiting the predictive power sufficient for reliable design. Our methodology is demonstrated by re-using the presented surrogate for the design of high-performance transmitarrays operating at various frequency ranges of 8-14 GHz, 22-28 GHz, and 28-36 GHz.

  • Optimal retrofit strategy using viscous dampers between adjacent RC and SMRFs prone to earthquake‑induced pounding
    • Neda Asgarkhani
    • Farzin Kazemi
    • Robert Jankowski
    2023 Pełny tekst Archives of Civil and Mechanical Engineering

    Nowadays, retrofitting-damaged buildings is an important challenge for engineers. Finding the optimal placement of Viscous Dampers (VDs) between adjacent structures prone to earthquake-induced pounding can help designers to implement VDs with optimizing the cost of construction and achieving higher performance levels for both structures. In this research, the optimal placement of linear and nonlinear VDs between the 3-story, 5-story, and 9-story Steel and RC Moment-Resisting Frames (SMRFs and RC MRFs) is investigated. It is shown that the pounding phenomenon can significantly affect the seismic performance capacities of buildings during earthquakes, and using VDs can improve the seismic limit-state capacities of buildings for retrofitting purposes. For this goal, the seismic limit-state capacities of both colliding structures were assessed using Incremental Dynamic Analysis (IDA) assuming Near-fault Pulse-Like, Near-fault No-Pulse, and Far-Fault seismic records suggested by FEMA-P695. To perform IDAs, structures were modeled according to the seismic codes using a developed algorithm in Matlab and OpenSees software with the ability to remove a collapsed structure during the analysis. The results present an optimal placement for using VDs between structures and also compare the possible conditions to implement VDs. Using these results, engineers can approximately predict the seismic performance levels of both structures prone to earthquake-induced pounding and their final performance after retrofitting. Finally, retrofitting modification factors were proposed to help designers to predict the limit-state performance levels of retrofitted colliding structures without involving complicated and time-consuming analyses.

  • Optimisation of cooperation of hybrid renewable energy sources with hydrogen energy storage toward the lowest net present cost
    • Jakub Łukasik
    • Marcin Jewartowski
    • Jan Wajs
    2023 Pełny tekst Instal

    The paper presents the results of a technical and economic analysis of the power supply for a model industrial facility based on intermittent renewable energy sources in the form of wind turbines and photovoltaic modules, supplemented with hydrogen energy storage. The adopted power supply strategy assumed the maximisation of self-consumption of self-produced electricity. Six variants were considered, including two with an energy storage system, three using only RES, and a reference variant in which the model facility is powered by the power grid. The modelling and optimisation of the proposed variants was carried out in the HOMER software, in terms of the lowest net present cost. The results obtained indicate that the most advantageous configuration is a grid-connected hybrid renewable energy system consisting of wind turbines and a photovoltaic power plant. A system with hydrogen energy storage is much more profitable than powering the facility from the grid. The profitability of hydrogen energy storage increases even more with the projected increase in electricity prices and the falling prices of hydrogen system components.

  • Optimization and Modeling of Cr (VI) Removal from Tannery Wastewater onto Activated Carbon Prepared from Coffee Husk and Sulfuric Acid (H2SO4) as Activating Agent by Using Central Composite Design (CCD)
    • Worku Firomsa Kabeta
    • Temesgen Amibo
    • Surafel Mustafa Bayan
    • Abreham Bekele Bayu
    2023 Pełny tekst Journal of Environmental and Public Health

    The primary goal of this research is to lower the hexavalent chromium (Cr (VI)) concentration that has occurred from the growth of the tannery industry. As a result, the potential for heavy metal concentration is increasing day by day. Industrial effluent containing Cr (VI) contributes significantly to water pollution. Chromium hexavalent ion (Cr (VI)) in wastewater is extremely hazardous to the environment. It is critical to address such a condition using activated carbon derived from biomass. Adsorption is one of the most successful methods for removing hexavalent chromium from wastewater. Treated wastewater has no substantial environmental contamination consequences. The ash content, moisture content, volatile matter content, and fixed carbon content of wet coffee husk were 3.51, 10.85, 68.33, and 17.31, respectively. The physicochemical properties of coffee husk-based activated carbon (CHBAC) obtained during experimentation were pH, porosity, the yield of CHBAC, bulk density, point of zero charges, and specific surface area of 5.2, 58.4 percent, 60.1 percent, 0.71 g/mL, 4.19, and 1396 m2/g, respectively, indicating that CHBAC has a higher capacity as an adsorbent medium. For optimization purposes, the parameters ranged from pH (0.3–3.7), dose (2.3–5.7) , and contact time (0.3–3.7) hr. The quadratic models were chosen for optimization, and the value for the model was significant since it was less than 0.05, but the lack of fit model was inconsequential because it was more than 0.05. The optimum adsorption obtained with numerical optimization of Cr (VI) was 97.65 percent. This was obtained at a pH of 1.926, a dose of 4.209 g/L, and a contact time of 2.101 hours. This result was observed at a pH of 1.93, a dosage of 4.2 g/L, and a contact duration of 2.1 hours. The desirability obtained during numerical optimization was 1. Coffee husk-based activated carbon has a bigger surface area, and it has a stronger ability to absorb hexavalent chromium from tannery wastewater effluents.

  • Optimization of a Fabric Phase Sorptive Extraction protocol for the isolation of six bisphenols from juice pouches to be analysed by high performance liquid chromatography coupled with diode array detector
    • Paweł Kubica
    • Natasa Kalogiouri
    • Abuzar Kabir
    • Kenneth G. Furton
    • Victoria F. Samanidou
    2023 JOURNAL OF CHROMATOGRAPHY A

    Fabric Phase Sorptive Extraction (FPSE) combined with high pressure liquid chromatography using to diode array detection (HPLC-DAD) was applied for the simultaneous determination of bisphenols (BPA, BPB, BPC, BPE, BPF, BPS) in juice pouches. The FPSE procedure was optimized with regards to the critical parameters that affect the performance of the method including the selection of the FPSE membrane type and size, adsorption time, extraction time, solvent volume desorption, magnetic stirring ratio, and salt addition. The FPSE membrane could be reused up to 14 times. The developed FPSE-HPLC-DAD method was validated in terms of linearity, sensitivity, accuracy andprecision. The limits of detection (LODs) were lower than 6.9 ng/mL, while the limits of quantification (LOQs) were lower than 21 ng/mL. The results obtained are satisfactory in terms of precision, accuracy and repeatability, with recoveries above 86% and CV values below 9.5%. The FPSE-HPLC-DAD method was successfully applied in the determination of six bisphenols in juice samples stored in pouches.

  • Optimization of adsorption of methyl orange from aqueous solution by magnetic CoFe2O4/ZnAl-layered double hydroxide composite using response surface methodology
    • Yiene Molla Desalegn
    • Endrias Adane Bekele
    • Temesgen Amibo
    • Temesgen Debelo Desissa
    2023 Pełny tekst Materials Research Express

    The CoFe2O4/ZnAl-layered double hydroxide (LDH) composite was successfully developed through a facile co-precipitation method, characterized, and applied as an effective adsorbent for the removal of methyl orange (MO) dye from aqueous solutions. The central composite design (CCD) of the response surface methodology (RSM) was employed to estimate and optimize process variables such as initial MO concentrations, solution pH, adsorbent dosage, and contact time. 98.878% adsorption efficiency was obtained at an initial concentration of 18.747 mg l−1 of MO, with an adsorbent dosage of 0.048 g, a solution pH of 2.770, and a contact time of 85.890 min. Analysis of variance (ANOVA) confirmed the significance of the predicted model (R2 = 0.9844). Kinetic and equilibrium studies indicated that the experimental data for MO adsorption were best described by pseudo-second-order kinetic and Langmuir models. The maximum monolayer adsorption capacity of the CoFe2O4/ZnAl-LDH for MO was 42.3 mg g−1.

  • Optimization of Bread Production Using Neuro-Fuzzy Modelling
    • Tomasz Boiński
    • Julian Szymański
    2023

    Automation of food production is an actively researched domain. One of the areas, where automation is still not progressing significantly is bread making. The process still relies on expert knowledge regarding how to react to procedure changes depending on environmental conditions, quality of the ingredients, etc. In this paper, we propose an ANFIS-based model for changing the mixer speed during the kneading process. Although the recipes usually indicate the time for which the mixing should be done using slow and fast mixing speeds, however, it is the human, who makes the final decision as the mixers differ in terms of the mixing quality, speed, etc. Furthermore, unexpected differences in flour quality or room conditions can impact the time required to mix the ingredients. In the paper, different methods for fuzzy modeling are described and analyzed. The tested models are compared using both generated and real data and the best solution is presented.

  • Optimization of parallel implementation of UNRES package for coarse‐grained simulations to treat large proteins
    • Adam Sieradzan
    • Jordi Sans‐Duñó
    • Emilia Lubecka
    • Cezary Czaplewski
    • Agnieszka Lipska
    • Henryk Leszczyński
    • Krzysztof Ocetkiewicz
    • Jerzy Proficz
    • Paweł Czarnul
    • Henryk Krawczyk
    • Adam Liwo
    2023 Pełny tekst JOURNAL OF COMPUTATIONAL CHEMISTRY

    We report major algorithmic improvements of the UNRES package for physics-based coarse-grained simulations of proteins. These include (i) introduction of interaction lists to optimize computations, (ii) transforming the inertia matrix to a pentadiagonal form to reduce computing and memory requirements, (iii) removing explicit angles and dihedral angles from energy expressions and recoding the most time-consuming energy/force terms to minimize the number of operations and to improve numerical stability, (iv) using OpenMP to parallelize those sections of the code for which distributed-memory parallelization involves unfavorable computing/communication time ratio, and (v) careful memory management to minimize simultaneous access of distant memory sections. The new code enables us to run molecular dynamics simulations of protein systems with size exceeding 100,000 amino-acid residues, reaching over 1 ns/day (1 μs/day in all-atom timescale) with 24 cores for proteins of this size. Parallel performance of the code and comparison of its performance with that of AMBER, GROMACS and MARTINI 3 is presented.

  • Optimization of the distance between the vertical plates in the convective air heat exchanger
    • Michał Ryms
    • Krzysztof Tesch
    • Witold Lewandowski
    2023 INTERNATIONAL JOURNAL OF THERMAL SCIENCES

    This paper examines the influence of the distance between vertical plates on the intensity of free convective heat transfer along with the optimization of this distance. Experimental tests were carried out for one model channel of such an heat exchanger with widths , 0.085 and 0.18 m. This channel, open at the top and sides, was formed by two isothermal symmetrically heated parallel vertical plates of dimensions m and m. The influence of the heating surface temperatures , 40, 50, 55, 60 and 70 °C on the convective temperature fields and velocity generated inside the channels was investigated. Directly measured temperature fields, as well as velocity fields measured indirectly using the NRP, enabled the thermodynamic parameters of the heat exchanger to be determined. Based on the temperature gradient distribution on the wall, its average value was determined for each of the plates and for the entire channel, after which the heat flux transferred from the plates was calculated. The heat flux transferred with the air and the efficiency of heat transfer in the channel were determined using the balance method based on the average temperatures and air velocities at the inlet and and at the outlet and of the channel obtained from the temperature and velocity fields. A grid placed vertically in the channel, halfway across the panel width and perpendicular to the heating surfaces was used to detect the temperature field in air. The image and matrix of these temperatures were determined using a thermal imaging camera. The numerical reconstruction procedure (NRP) was used to determine the velocity field.

  • Optimization of the femtosecond laser impulse for excitation and the Spin-Orbit mediated dissociation in the NaRb Dimer
    • Jan Kozicki
    • Patryk Jasik
    • Tymon Kilich
    • Józef Sienkiewicz
    2023 Pełny tekst JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER

    We study the dynamics of multiple coupled states under the influence of an arbitrary time-dependent external field to investigate the femtosecond laser-driven excitation and the spin-orbit mediated dissociation in the NaRb dimer. In this process, the dimer is excited from the ground triplet state 1^3Sigma+ to the 1^3Pi state using the femtosecond laser impulse and the spin-orbit coupling between the 1^3Pi and 2^1Sigma+ states results in the singlet-triplet transition. The laser impulse parameters are optimised to obtain maximum yield in electronic states correlating with the first excited atomic asymptote. We observe the detailed population statistics and power-law decay of these states. Finally, the analysis of the population oscillations allows us to determine the optimal time delay for dumping the molecule to its absolute ground state.

  • Optimization of the Hardware Layer for IoT Systems using a Trust Region Method with Adaptive Forward Finite Differences
    • Adrian Bekasiewicz
    2023 Pełny tekst IEEE Internet of Things Journal

    Trust-region (TR) algorithms represent a popular class of local optimization methods. Owing to straightforward setup and low computational cost, TR routines based on linear models determined using forward finite differences (FD) are often utilized for performance tuning of microwave and antenna components incorporated within the Internet of Things systems. Despite usefulness for design of complex structures, performance of TR methods vastly depends on the quality of FD-based local models. The latter are normally identified from perturbations determined a priori using either rules-of-thumb, or as a result of manual tuning. In this work, a framework for automatic determination of FD steps and their adjustment between the TR algorithm iterations is proposed. The method involves numerical optimization of perturbations so as to equalize the objective function changes w.r.t. the center design to the desirable precision. To maintain acceptable cost, the FD-tuning procedure is executed using the same approximation model as the one exploited in the course of the structure optimization. The proposed framework has been tested on a total of twelve design problems. Furthermore, the presented method has been thoroughly validated against TR-algorithms with static, a priori selected perturbations. Numerical results indicate that the proposed framework provides up to 50% performance improvement (in terms of the optimized designs quality) compared to the state-of-the-art TR-based approaches. Usefulness of the proposed method for the real-world Internet of Things systems has been implicitly demonstrated through utilization of one of the optimized structures in a hardware layer of a real-time localization system.

  • Optimization of the System for Determining the Volume of Tissue Needed for Breast Reconstruction
    • Julia Czałpińska
    • Andżelika Janicka
    • Jakub Rzepkowski
    • Mariusz Kaczmarek
    • Tomasz Kocejko
    • Jo Kang-Hyun
    2023

    This article presents techniques for reconstructing surfaces and volume calculations using a point cloud generated from 3D imaging. The main objective of this article was to optimize the voxel size for the most accurate representation of the surface of the female breast. We experimented with different methods for determining volume using images from the Intel D435i camera. In addition, we designed application and measurement station tailored specifically to the clinical requirements. Ultimately, our results show that 3D imaging systems can effectively determine breast volume for surgical procedures.

  • Optimization of vortex-assisted hydrophobic magnetic deep eutectic solvent-based dispersive liquid phase microextraction for quantification of niclosamide in real samples
    • Nail Altunay
    • Roberto Castro Munoz
    • Hameed Haq
    2023 FOOD CHEMISTRY

    In this manuscript, a green and fast vortex-assisted hydrophobic magnetic deep eutectic solvent-based dispersive liquid phase microextraction (VA-HMDES-DLPME) method was developed for the selective extraction and determination of niclosamide in read samples, including rice, medicine tablets, and water samples. Here, hydrophobic magnetic deep eutectic solvents were used as the extracting solvent without requiring any centrifugation step. In the light of preliminary experiments, important parameters, such as volume of extraction solvent, pH, acetonitrile volume and vortex time, affecting the extraction efficiency of niclosamide were optimized using a Box–Behnken design. The linear dynamic range (0.25–120 µg/L), the limit of detection (0.08 µg/L), the limit of quantitation (0.25 µg/L), preconcentration factor (1 8 0), and enrichment factor (1 3 0) of the method were determined using optimized data. In particular, the validation parameters of the optimized VA-HMDES-DLPME, including robustness, matrix effect accuracy, and precision, were investigated. In addition to this, intra- and inter-day precisions were determined as ≤3.5 % and ≤4.1%, respectively. Finally, the optimized method was successfully used for the extraction of niclosamide in the selected samples prior to spectrophotometric analysis.

  • Optimized Computational Intelligence Model for Estimating the Flexural Behavior of Composite Shear Walls
    • Masoomeh Mirrashid
    • Hosein Naderpour
    • Denise-Penelope N. Kontoni
    • Anna Jakubczyk-Gałczyńska
    • Robert Jankowski
    • Tan N. Nguyen
    2023 Pełny tekst Buildings

    This article presents a novel approach to estimate the flexural capacity of reinforced concrete-filled composite plate shear walls using an optimized computational intelligence model. The proposed model was developed and validated based on 47 laboratory data points and the Transit Search (TS) optimization algorithm. Using 80% of the experimental dataset, the optimized model was selected by determining the unknown coefficients of the network-based computational structure. The remaining 20% of the data was used to evaluate the accuracy of the model, and the best-performing structure was selected. Furthermore, the final neural network details were subjected to statistical analysis to extract a user-friendly formula, making it easier to apply in practice. The proposed ANN model and the proposed user-friendly formula were then compared with the AISC 341-16 and experimental results and demonstrated their efficacy in predicting the flexural behavior of composite shear walls. Overall, the proposed approach provides a more reliable and efficient framework for estimating the flexural behavior of composite shear walls.

  • Optimized Deep Learning Model for Flood Detection Using Satellite Images
    • Andrzej Stateczny
    • Hirald Dwaraka Praveena
    • Ravikiran Hassan Krishnappa
    • Kanegonda Ravi Chythanya
    • Beenarani Balakrishnan Babysarojam
    2023 Pełny tekst Remote Sensing

    The increasing amount of rain produces a number of issues in Kerala, particularly in urban regions where the drainage system is frequently unable to handle a significant amount of water in such a short duration. Meanwhile, standard flood detection results are inaccurate for complex phenomena and cannot handle enormous quantities of data. In order to overcome those drawbacks and enhance the outcomes of conventional flood detection models, deep learning techniques are extensively used in flood control. Therefore, a novel deep hybrid model for flood prediction (DHMFP) with a combined Harris hawks shuffled shepherd optimization (CHHSSO)-based training algorithm is introduced for flood prediction. Initially, the input satellite image is preprocessed by the median filtering method. Then the preprocessed image is segmented using the cubic chaotic map weighted based k-means clustering algorithm. After that, based on the segmented image, features like difference vegetation index (DVI), normalized difference vegetation index (NDVI), modified transformed vegetation index (MTVI), green vegetation index (GVI), and soil adjusted vegetation index (SAVI) are extracted. The features are subjected to a hybrid model for predicting floods based on the extracted feature set. The hybrid model includes models like CNN (convolutional neural network) and deep ResNet classifiers. Also, to enhance the prediction performance, the CNN and deep ResNet models are fine-tuned by selecting the optimal weights by the combined Harris hawks shuffled shepherd optimization (CHHSSO) algorithm during the training process. This hybrid approach decreases the number of errors while improving the efficacy of deep neural networks with additional neural layers. From the result study, it clearly shows that the proposed work has obtained sensitivity (93.48%), specificity (98.29%), accuracy (94.98%), false negative rate (0.02%), and false positive rate (0.02%) on analysis. Furthermore, the proposed DHMFP–CHHSSO displays better performances in terms of sensitivity (0.932), specificity (0.977), accuracy (0.952), false negative rate (0.0858), and false positive rate (0.036), respectively.

  • Optimized photodegradation of palm oil agroindustry waste effluent using multivalent manganese–modified black titanium dioxide
    • Rab Nawaz
    • Sajjad Haider
    • Muzammil Anjum
    • Vipin Kumar Oad
    • Adnan Haider
    • Rawaiz Khan
    • Muhammad Aqif
    • Tahir Hanif
    • Nasruulah Khan
    2023 Pełny tekst ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

    This article presents a methodological approach to use manganese (Mn3+Mn7+)-modified black titanium dioxide (Mn/BTiO2) as a photocatalyst to optimize and improve visible-light-driven photodegradation of treated agro-industrial effluent (TPOME). A modified wet chemical process was used to prepare BTiO2. The BTiO2 was then wet impregnated with Mn and calcined at 300 °C for 1 h to produce Mn/BTiO2. The activity of Mn/BTiO2 was investigated in terms of photo-assisted elimination of chemical oxygen demand (COD), phenolic compounds (PCs), color, and total organic carbon (TOC). Using the design of experiments (DOE), the conditions of the photocatalytic process, including photocatalyst loading, Mn concentration, hydrogen peroxide (H2O2) dose, and irradiation time, were optimized. Under the optimum conditions (0.85 g/L photocatalyst loading, 0.048 mol/L H2O2 dose, 0.301 wt.% Mn concentration, and 204 min irradiation time) COD, PCs, color, and TOC removal efficiencies of 88.87%, 86.04%, 62.8%, and 84.66%, respectively, were obtained. Statistical analysis showed that the response variable’s removal from TPOME estimation had high R2 and low RMSE, MSE, MAD, MAE, and MAPE values, indicating high reliability. This study demonstrated the significant potential of the developed photocatalytic system for the treatment of waste effluent generated by the palm oil industry and other agro-industries, with the ability to simultaneously reduce a number of organic pollution indicators (OPIs).

  • Optimizing Medical Personnel Speech Recognition Models Using Speech Synthesis and Reinforcement Learning
    • Andrzej Czyżewski
    2023 Pełny tekst Journal of the Acoustical Society of America

    Text-to-Speech synthesis (TTS) can be used to generate training data for building Automatic Speech Recognition models (ASR). Access to medical speech data is because it is sensitive data that is difficult to obtain for privacy reasons; TTS can help expand the data set. Speech can be synthesized by mimicking different accents, dialects, and speaking styles that may occur in a medical language. Reinforcement Learning (RL), in the context of ASR, can be used to optimize a model based on specific goals. A model can be trained to minimize errors in speech-to-text transcription, especially for technical medical terminology. In this case, the "reward" to the RL model can be negatively proportional to the number of transcription errors. The paper presents a method and experimental study from which it is concluded that the combination of TTS and RL can enable the creation of a speech recognition model that is better suited to the specific needs of medical personnel, helping to expand the training data and optimize the model to minimize transcription errors. The learning process used reward functions based on Mean Opinion Score (MOS), a subjective metric for assessing speech quality, and Word Error Rate (WER), which evaluates the quality of speech-to-text transcription.

  • Optimum Choice of Randomly Oriented Carbon Nanotube Networks for UV-Assisted Gas Sensing Applications
    • Katarzyna Drozdowska
    • Adil Rehman
    • Janusz Smulko
    • Aleksandra Krajewska
    • Bartlomiej Stonio
    • Pavlo Sai
    • Aleksandra Przewłoka
    • Maciej Filipiak
    • Krystian Pavłov
    • Grzegorz Cywinski
    • Dmitry V. Lyubchenko
    • Sergey Rumyantsev
    2023 Pełny tekst ACS Sensors

    We investigated the noise and photoresponse characteristics of various optical transparencies of nanotube networks to identify an optimal randomly oriented network of carbon nanotube (CNT)-based devices for UV-assisted gas sensing applications. Our investigation reveals that all of the studied devices demonstrate negative photoconductivity upon exposure to UV light. Our studies confirm the effect of UV irradiation on the electrical properties of CNT networks and the increased photoresponse with decreasing UV light wavelength. We also extend our analysis to explore the lowfrequency noise properties of different nanotube network transparencies. Our findings indicate that devices with higher nanotube network transparencies exhibit lower noise levels. We conduct additional measurements of noise and resistance in an ethanol and acetone gas environment, demonstrating the high sensitivity of higher-transparent (lower-density) nanotube networks. Overall, our results indicate that lower-density nanotube networks hold significant promise as a viable choice for UV-assisted gas sensing applications.

  • Optimum number of actuators to minimize the cross-sectional area of prestressable cable and truss structures
    • Ahmed Manguri
    • Najmadeen Saeed
    • Farzin Kazemi
    • Marcin Szczepański
    • Robert Jankowski
    2023 Structures

    This paper describes a new computational method for determining the optimum number of actuators to design the optimal and economic cross-sectional area of pin-jointed assemblies based on the conventional force method. The most active members are selected to be prestressed to redistribute stress in the whole structure, resulting in regulating the internal force of bars that face high stress. Reducing stress in critical members allows the designers to select smaller cross-sectional areas than before. Furthermore, the maximum absolute displacement of the structures before the optimization is set as a limit for the displacement of the optimized structures. The derived equations from the force method are subjected to the optimization algorithms (i.e., sequential quadratic programming (SQP), trust-region reflective, active set, and interior point) to minimize the necessary number of actuators for prestressing. The optimization procedure is done in two ways: first, by minimizing the number of actuators for prestressing through implementing the fmincon function, and second, by selecting the most economical area via prestressing the structure before loading. The method is applied to the numerical models of two cable and four truss structures that were previously studied. The outcomes show that by actuating as few actuators as possible, the area of cable and truss structures can be minimized up to 17% and 27 %, respectively. Moreover, 5% improvement can be obtained applying the current technique to the optimized trusses by quoted methods. The outcomes are compared with results from the literature. Moreover, the results obtained from MATLAB are verified by SAP2000 software.

  • Optimum shapes and dimensions of rubber bumpers in order to reduce structural pounding during seismic excitations
    • Seyed Mohammad Khatami
    • Hosein Naderpour
    • Alireza Mortezaei
    • M. Maddah
    • Natalia Lasowicz
    • Robert Jankowski
    2023 Pełny tekst Structures

    Large displacement of structures observed during seismic excitations may lead to collisions between two adjacent, insufficiently-separated buildings and may result in major damages of both of them. In many building codes, appropriate equations or approximately recommended distances between structures in order to avoid pounding hazard have been introduced. Unfortunately, further, more detailed considerations show that safety situation or economic aspects are not always satisfied due to the collisions between buildings and the cost of land, respectively. Hence, researchers have studied other approaches of reducing the negative pounding effects. Such methods include the use of tuned mass or liquid dampers. Moreover the increase in stiffness of building or reduction of mass of the structure are still considered. In this paper, another approach is considered by the application of rubber bumpers placed between buildings. The bumpers are attached at each story to absorb energy during impact. Several different shapes and dimensions of bumper elements were numerically investigated so as to find the most effective ones most effective in reducing structural pounding negative effects. For this purpose, two MDOF models of 3-story and 4-story buildings were firstly considered. Such parameters as lateral displacement, damage index, dissipated energy and impact forces were calculated and depicted as the results of numerical study. Then, different shapes and dimensions of bumpers were parametrically investigated.

  • Optymalizacja doboru prawa konstytutywnego membrany o strukturze plecionej
    • Daniil Reznikov
    2023 Pełny tekst

    Celem niniejszej dysertacji jest opracowanie zagadnienia optymalizacyjnego pozwalającego dobrać model konstytutywny opisujący mechaniczne zachowanie membrany technicznej. Do analizy wybrano membrany plecione, stosowane w medycynie, tzw. siatki chirurgiczne. W celu wykonania identyfikacji praw konstytutywnych, wykonano dwuosiowe rozciąganie próbek materiałów, otrzymując wskazanie na nieliniowe anizotropowe zachowanie materiałów. W wyniku tego, do opisania zależności pomiędzy naprężeniem, a odkształceniem przyjęto teorię hipersprężystości. Przeprowadzone z różnymi sterowaniami testy mechaniczne próbek doprowadziły do uzyskania różnych kompletów parametrów rozważanych praw konstytutywnych. W celu identyfikacji prawa opisującego pracę materiałów w warunkach naturalnych przeprowadzono analizę optymalizacyjną w której funkcja celu odnosi się do pozycji maksymalnej reakcji podporowej wyznaczonej w modelu numerycznym implantu oraz do pozycji maksymalnej reakcji wyznaczonej eksperymentalnie. Przeprowadzona analiza wskazuje, że model konstytutywny membrany plecionej silnie zależy od rodzaju wykonanego testu mechanicznego materiału, a wybór prawa opisującego rzeczywistą pracę danego materiału może być zrobiony w odniesieniu do eksperymentu z symetrycznym obciążeniem danego materiału.

  • Optymalizacja zasobów chmury obliczeniowej z wykorzystaniem inteligentnych agentów w zdalnym nauczaniu
    • Piotr Dryja
    2023 Pełny tekst

    Rozprawa dotyczy optymalizacji zasobów chmury obliczeniowej, w której zastosowano inteligentne agenty w zdalnym nauczaniu. Zagadnienie jest istotne w edukacji, gdzie wykorzystuje się nowoczesne technologie, takie jak Internet Rzeczy, rozszerzoną i wirtualną rzeczywistość oraz deep learning w środowisku chmury obliczeniowej. Zagadnienie jest istotne również w sytuacji, gdy pandemia wymusza stosowanie zdalnego nauczania na dużą skalę lub rosnące koszty efekty ograniczają naukę stacjonarną. W dysertacji opracowano model alokacji inteligentnych agentów pedagogicznych, modułów systemu zdalnego nauczania oraz solwerów do serwerów w chmurze. Sformułowano zagadnienie wyznaczania reprezentacji rozwiązań Pareto-optymalnych. Opracowano wielokryterialny algorytm ewolucji różnicowej, za pomocą którego minimalizuje się cztery kryteria takie, jak: obciążenie CPU newralgicznego hosta, obciążenie komunikacyjne krytycznego węzła, koszt serwerów oraz łączny pobór mocy elektrycznej. W celu eksperymentalnej weryfikacji poprawności modelu zaprojektowano demonstrator chmury edukacyjnej w oparciu o wybrane zasoby Politechniki Gdańskiej oraz Politechniki Warszawskiej. Przeprowadzono wielowariantowe symulacje migracji inteligentnych agentów w środowisku Moodle na platformie OpenStack. Eksperymenty numeryczne potwierdziły, że wykorzystanie wielokryterialnej metaheurystyki opartej na ewolucji różnicowej umożliwia wyznaczenie wyższej jakości rozwiązań niezdominowanych niż rozwiązania uzyskane za pomocą innych metaheurystyk, takich jak: algorytm ewolucyjny, programowanie genetyczne, algorytm wyszukiwania harmonii oraz algorytm roju cząstek.

  • Organic Supercritical Thermodynamic Cycles with Isothermal Turbine
    • Marian Piwowarski
    • Krzysztof Kosowski
    • Marcin Richert
    2023 Pełny tekst ENERGIES

    Organic Rankine cycles (ORC) are quite popular, but the overall efficiencies of these plants are rather very low. Numerous studies have been conducted in many scientific centers and research centers to improve the efficiency of such cycles. The research concerns both the modification of the cycle and the increase in the parameters of the medium at the inlet to the turbine. However, the efficiency of even these modified cycles rarely exceeds 20%. The plant modifications and the optimization of the working medium parameters, as a rule, lead to cycles with the high pressure and high temperature of live vapor and with a regenerator (heat exchanger) for the heating, vaporization and superheating of the medium. A new modified cycle with supercritical parameters of the working medium and with a new type of turbine has been described and calculated in the paper. For the first time, the isothermal turbine is proposed for supercritical organic cycles, though this solution is known as the Ericsson cycle for gas turbines. The innovative cycle and the usual ORC plants are characterized by almost identical block diagrams, while in the proposed cycle, the work of the turbine is obtained as a result of isothermal expansion and not in an adiabatic process. The analysis has been performed for 11 different working media and two cycles. The calculations have shown that power plants with isothermal expansion achieve better efficiency than cycles with adiabatic turbines. For example, the rise in efficiency changes from 8 percentage points for R245fa up to 10 percentage points for acetone. The calculations have proved that it is possible to obtain efficiency exceeding 50% for organic power plants. This is an outstanding result compared with modern steam and gas turbine units.

  • Orientation-aware ship detection via a rotation feature decoupling supported deep learning approach
    • Xinqiang Chen
    • Hao Wu
    • Bing Han
    • Wei Liu
    • Jakub Montewka
    • Ryan Wen Liu
    2023 ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE

    Ship imaging position plays an important role in visual navigation, and thus significant focuses have been paid to accurately extract ship imaging positions in maritime videos. Previous studies are mainly conducted in the horizontal ship detection manner from maritime image sequences. This can lead to unsatisfied ship detection performance due to that some background pixels maybe wrongly identified as ship contours. To address the issue, we propose a novel rotational you only look once (YOLO) based model (RYM) to accurately yet fast detect ships from maritime images by considering ship rotation angle. The proposed RYM model are designed to detect tilted ships from images with the help of a rotation decoupled (RD) head, attentional mechanism and bidirectional feature network (BiFPN). The experimental results suggested that RYM can obtain satisfied ship detection performance considering that average accuracy reaches 96.7%. The precision and recall indicators are 93.2% and 94.7%, respectively. The proposed framework can be applied into real-time ship detection task due to that the processing speed is 45.6 frames per second (FPS).

  • Orunia # PRZYSTANEK W PODRÓŻY wystawa projektowych prac studenckich
    • Agnieszka Kurkowska
    • Alicja Karaś
    2023

    Podróżujemy. Lokalnie i pokonując granice. Przenosimy się z potrzeby i konieczności. Przenosimy się w czasie I w wyobraźni. Przywołujemy wspomnienia, marzymy. Podróż wymaga przystanków: czasu wypoczynku i czasu refleksji. Podróż przez życie wymaga od nas stworzenia zrównoważonego schronienia dla naszej fizycznej egzystencji. Nikt z nas nie istnieje w odosobnieniu. Otacza nas przyroda, dotyczy dziedzictwo, które współtworzymy, dotykają codzienne problemy. łączy troska o planetę. Wspólny system wartości i dążenia kierunkują naszą podróż. Spotykamy w niej innych ludzi i przyglądamy się samym sobie. Studenci przygotowali propozycje obiektów architektonicznych ulokowanych na terenie Oruni, które są „PRZYSTANKAMI W PODRÓŻY”.

  • Osteoblast and bacterial cell response on RGD peptide‐functionalized chitosan coatings electrophoretically deposited from different suspensions on Ti13Nb13Zr alloy
    • Łukasz Pawłowski
    • Szymon Mania
    • Adrianna Banach-Kopeć
    • Michał Bartmański
    • Anna Ronowska
    • Kacper Jurak
    • Aleksandra Mielewczyk-Gryń
    • Natalia Karska
    • Sylwia Rodziewicz-Motowidło
    • Andrzej Zieliński
    2023 Pełny tekst JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS

    Metallic materials for long-term load-bearing implants still do not provide high antimicrobial activity while maintaining strong compatibility with bone cells. This study aimed to modify the surface of Ti13Nb13Zr alloy by electrophoretic deposition of a chitosan coating with a covalently attached Arg-Gly-Asp (RGD) peptide. The suspensions for coating deposition were prepared in two different ways either using hydroxyacetic acid or a carbon dioxide saturation process. The coatings were deposited using a voltage of 10 V for 1 min. The prepared coatings were examined using SEM, EDS, FTIR, and XPS techniques. In addition, the wettability of these surfaces, corrosion resistance, adhesion of the coatings to the metallic substrate, and their antimicrobial activity (E. coli, S. aureus) and cytocompatibility properties using the MTT and LDH assays were studied. The coatings produced tightly covered the metallic substrate. Spectroscopic studies confirmed that the peptide did not detach from the chitosan chain during electrophoretic deposition. All tested samples showed high corrosion resistance (corrosion current density measured in nA/cm2). The deposited coatings contributed to a significant increase in the antimicrobial activity of the samples against Gram-positive and Gram-negative bacteria (reduction in bacterial counts from 99% to, for CS-RGD-Acid and the S. aureus strain, total killing capacity). MTT and LDH results showed high compatibility with bone cells of the modified surfaces compared to the bare substrate (survival rates above 75% under indirect contact conditions and above 100% under direct contact conditions). However, the adhesion of the coatings was considered weak.

  • Overcoming Challenges of Virtual Scrum Teams: Lessons Learned Through an Action Research Study
    • Jędrzej Babło
    • Bartosz Marcinkowski
    • Adam Przybyłek
    2023

    After the COVID-19 breakout, agile teams found themselves in situations that “pure agilists” and textbooks on agile methods had preferred to ignore. Whereas agile mindsets helped them to quickly shift to remote work, mere virtualization of agile practices often proved insufficient, and several challenges emerged. This paper reports on an Action Research project carried out in Lufthansa Systems Poland with the aim of (1) revisiting their ad-hoc actions to adapt to remote work; and (2) elaborating systematic solutions to maintain efficiency in such a setting. With our assistance, the participating teams found measures to mitigate issues posed by the new work environment. They devised an inter-team communication model to improve the effectiveness of information exchange that had declined in the absence of spontaneous, face-to-face communication. Moreover, they employed several other mitigation strategies, including working at least one day per week in the office, keeping webcams on during online meetings, and recapping meetings at the end of a session. Our study largely supports previous findings indicating that Scrum can be effectively applied beyond its comfort zone but also suggests that for adaptations to be successful and comprehensive, they should be developed in a structured manner.

  • Overview of new product development strategies and models
    • Alina Guzik
    2023 Pełny tekst Catallaxy

    Motivation: The motivation for the overview presented in this article is to provide a starting point for considering whether existing new product development methodology and its level of detail allows product teams to develop high-quality and business-effective product concepts. Aim: The aim of this article is recognise the current state of research into new product development methodology and to present the strategies and models for New Product Development (NPD). Materials and methods: The systematic review of the literature was applied in the article. Results: The first section outlines the main strategies for new product development and how they are divided by methodological stance, degree of planning, search pattern, focus and response. The second part discusses the known models of new product development including: the craft model and the 5 generations based on the innovation models described by Rothwell and the stages of the manufacturing process defined in the literature. Part four looks at new trends in new product development, including: Open Innovation, Rapid Product Development (RPD), Agile New Product Development (ANPD), Sustainable New Product development (SNPD), the Design Thinking method and the new technologies of Industry 4.0.

  • Overview of the Synthesis and Catalytic Reactivity of Transition Metal Complexes Based on C═P Bond Systems
    • Aleksandra Ziółkowska
    • Doroszuk Justyna
    • Łukasz Ponikiewski
    2023 Pełny tekst ORGANOMETALLICS

    This report provides an overview of the use of phosphaalkenes (C=P) in syntheses of various complexes. Going through successive complexes containing the d-block metals, we sought how this area of chemistry was formed over the years. Additionally, this work contains information on the possible coordination types and means of constructing the complexes. In addition, this review reveals the reactivities of phosphaalkene complexes with a strong emphasis on catalytic properties.

  • Oxide nanoparticle exsolution in Lu-doped (Ba,La)CoO3
    • Daria Balcerzak
    • Iga Szpunar
    • Ragnar Strandbakke
    • Sarmad W. Saeed
    • Calliope Bazioti
    • Aleksandra Mielewczyk-Gryń
    • Piotr Winiarz
    • Alfonso Carrillo
    • Maria Balaguer
    • José M Serra
    • Maria Gazda
    • Sebastian Wachowski
    2023 CRYSTENGCOMM

    This study investigated Lu doping of Ba0.5La0.5CoO3 and its influence on the exsolution of oxide nanoparticles (NPs). As a result of Lu doping, we observed the phase segregation into the main Ba0.4La0.6Co0.85Lu0.15O3 (BLCO–Lu) phase and the secondary Ba0.85La0.15Co0.75Lu0.25O3 (BCO–Lu) phase. We noticed the exsolution of BCO–Lu nanoparticles on the main BLCO–Lu phase. Moreover, the BLCO–Lu phase exsolved in the form of nanoparticles on the adjacent BCO–Lu grains. That shows that the phases are covered with mutually exsolved oxide NPs. In addition, trace amounts of the BaLuCo4O7 phase are detected. We noticed that the exsolved oxides even in the as-prepared sample were fine (average size of 18 nm), and well distributed with a dense population of NPs above 280 per 1 μm2. Furthermore, we showed that the size and shape of the exsolved oxide NPs can be controlled by varying the annealing temperature. For example, at 800 °C the exsolved oxides segregate and form two different shapes; spherical and cuboidal, with an average size of 31 nm and NP population of about 23 NPs per μm2. Meanwhile, with lowering the temperature to 400 °C the oxides form only spherical and quite evenly distributed NPs with the occurrence of 137 NPs per 1 μm2. The obtained results open the possibility of tailoring a novel, more catalytically active material for future applications in electrochemical devices.

  • Oxygen vacancy-enriched V2O5·nH2O nanofibers ink for universal substrates-tolerant and multi means-integratable NH3 sensing
    • Xiaxia Xing
    • Xinhua Zhao
    • Zhenxu Li
    • Lingling Du
    • Chen Wang
    • Dongliang Feng
    • Dongsheng Geng
    • Robert Bogdanowicz
    • Dachi Yang
    2023 CHEMICAL ENGINEERING JOURNAL

    Universal substrates-tolerant and multi means-integratable ammonia (NH3) sensing is highly desired in future Internet of Things in environmental monitoring, food security and early diagnosis of human diseases, however, is still less than satisfactory. Here, an oxygen vacancy-governed NH3 sensing has been developed with V2O5·nH2O nanofibers (NFs) ink, via combined thermal decomposition of ammonium metavanadate and dilution. As-obtained NH3 sensing ink takes on red colloids, in which the V2O5·nH2O NFs around 14 nm in diameter are interconnected. Beneficially, the fabric fiber decorated with V2O5·nH2O NFs ink displays excellent selectivity and ppb-concentration detection limit. Remarkably, V2O5·nH2O NFs ink is integrated over “hard” and “flexible” substrates such as glass, wood, paper, leaf and fabric with excellent tolerance by multi-integratable means such as writing, dipping and sewing. Theoretically, such NH3 sensing is interpreted that the bonding between V2O5 NFs and H2O modulates oxygen vacancy and thus adsorption sites, and the incorporation between crystal water and free one contributes to stable ink. Practically, A sensing device built with V2O5·3.1H2O NFs ink has been simulated to communicate with a smartphone with reliable NH3 sensing.

  • Oznaczanie zanieczyszczeń pierwiastkowych w wyrobach ceramicznych wytwarzanych z dodatkiem różnych odpadów poprodukcyjnych
    • Aleksandra Liczbińska
    • Bartłomiej Cieślik
    2023 Pełny tekst Analityka: Nauka i Praktyka

    Niektóre odpady zawierające związki toksyczne mogą zostać immobilizowane w nierozpuszczalnej matrycy materiału poprzez zmieszanie odpadów z materiałami stanowiącymi podstawowe surowce w producji

  • P92 steel and inconel 617 alloy welds joint produced using ERNiCr-3 filler with GTAW process: Solidification mechanism, microstructure, mechanical properties and residual stresses
    • Amit Kumar
    • Shailesh M. Pandey
    • Sachin Sirohi
    • Dariusz Fydrych
    • Chandan Pandey
    2023 Heliyon

    The objective of the current study was to analyse the microstructure, mechanical characteristics, and residual stresses of a dissimilar welded joint (DWJ) made of P92 steel and the Inconel alloy 617 (IN617) using the gas tungsten arc welding (GTAW) method. The ERNiCr-3 filler was selected to produce the conventional V groove (VG) and narrow V groove (NVG) butt joint. The filler deficient zones in the weldments, such as the filler deficient beach, i.e. unmixed zone (UZ), peninsula, and island, as well as the distinct heat-affected zone (HAZ), were visible near the interface of ERNiCr-3 filler weld and P92 steel due to the distinct differences in the chemical composition, microstructure, and mechanical properties between the filler and P92 base metal (BM). A very narrow partial melted zone (PMZ) and almost negligible UZ and HAZ were noticed at the interface of IN617 and ERNiCr-3 weld metal and it occurred mainly due to the similarity in microstructure and melting point. The austenitic microstructure of ERNiCr-3 filler weld was accompanied by precipitates enriched with Ti and Nb along with the inter-dendritic space. At room temperature, the mechanical properties of both the groove joints were evaluated, and the test results indicated that the welded joint satisfied the standard requirements for AUSC power plants' boiler applications. The tensile test results showed the failure from ERNiCr-3 filler weld with a tensile strength of 627 ± 2 MPa and 636 ± 3 MPa for VG and NVG welded joints, respectively. A poor weld metal impact toughness in comparison to the BMs was attributed to the presence of the brittle Ti(C, N) and Nb(C) particles in the interdendritic space. The impact toughness for the NVG weld joint was measured higher than for the VG weld joint. A significant hardness deviation was measured along the weldments that might be due to heterogeneous microstructure, i.e. UZ, HAZ, delta ferrite, and weld metal. To impart the ductility and temper the martensite in P92 HAZ, post-weld heat treatment (PWHT) was also performed, and a studied their effect on microstructure evolution across the weldments and mechanical properties. Groove design also showed a significant effect on residual stress variation. In comparison to conventional VG joints, the NVG joints exhibited superior mechanical properties and lower residual stress values.

  • Paintings
    • Krzysztof Wróblewski
    2023

    The painting as a curtain (...) A contradiction is therefore what constitutes a painting, and ambiguity is its right. As a young artist, I intuitively defined the work of art as a boundary. Over the years that intuition changed into a conviction that the particular form of art which is painting at the same time reveals and hides; it exists at this intersection of functions as a see-through curtain. We don’t know why there are some paintings which we constantly want to have before our eyes and others which we quickly forget. We will never have a complete answer to the question ‘what is a painting?’, because it resists being put into words – it is a part of a cloud, an element of a fog, from which multiplied imagery emerges. We give in to the charm of the curtain, but fictions are nothing bad. Thanks to the ability to create fictions and to believe in them we conquered the world. The reality, however we choose to define it, is woven with pictures. Krzysztof Wróblewski

  • Palmiarnia / Gdańsk
    • Joanna Kabrońska
    2023 Pełny tekst Architektura-Murator

    Palmiarnia w Parku Oliwskim zyskała nową formę w wyniku rozpoczętego w 2016 roku procesu rewitalizacji, podjętego w celu ochrony zabytkowych budynków, dostosowania ich do obecnych wymagań, a przede wszystkim podkreślenia kulturowych wartości dawnego ogrodu opackiego. Efektem prac rewitalizacyjnych jest dynamiczna, przejrzysta forma, zbudowana z zastosowaniem nowych technologii. Rotunda wraz z odrestaurowaną zabytkową oranżerią wpisuje się w poszukiwania przyszłej - odpowiadającej pojawiającym się wyzwaniom - roli Parku Oliwskiego, dając początek nowej interpretacji tego wyjątkowego miejsca.