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Politechniki Gdańskiej

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  • Evaluating the Use of Edge Device Towards Fall Detection in Smart City Environment
    • Tomasz Ludwisiak
    • Magdalena Mazur-Milecka
    • Tomasz Kocejko
    • Jacek Rumiński
    • Jo Kang-Hyun
    2024

    This paper presents the development and preliminary testing of a fall detection algorithm that leverages OpenPose for real-time human pose estimation from video feeds. The system is designed to function optimally within a range of up to 7 meters from ground-level cameras, focusing exclusively on detected human silhouettes to enhance processing efficiency. The performance of the proposed approach was evaluated using accuracy values obtained from experiments conducted on the Town Centre Dataset, Multiple Cameras Fall Dataset, and MPII Human Pose Dataset. The results demonstrate high accuracy levels for the investigated approaches, with the Dense Neural Network achieving accuracy rates of 98% on both the Town Centre & MPII Human Pose Dataset and the Multiple Cameras Fall Dataset. These findings highlight the effectiveness of the proposed fall detection system in accurately identifying fall events based on estimated human poses. This study details the algorithm's design, challenges in implementation, and potential for future IoT device integration, aiming to significantly enhance public safety and community monitoring capabilities.

  • Evaluating the Use of Edge Devices for Detection and Tracking of Vehicles in Smart City Environment
    • Tomasz Kocejko
    • Tomasz Neumann
    • Magdalena Mazur-Milecka
    • Natalia Kowalczyk
    • Jacek Rumiński
    • Jo Kang-Hyun
    • Miłosz Kaszyński
    • Tomasz Ludwisiak
    2024

    This paper introduces a Smart City solution designed to run on edge devices, leveraging NVIDIA's DeepStream SDK for efficient urban surveillance. We evaluate five object-tracking approaches, using YOLO as the baseline detector and integrating three Nvidia DeepStream trackers: IOU, NvSORT, and NvDCF. Additionally, we propose a custom tracker based on Optical Flow and Kalman filtering. The presented approach combines advanced machine learning and deep learning techniques to enhance object tracking in intelligent traffic management systems, contributing to the evolving landscape of urbanization. Experimental results highlight the challenges and potential improvements in tracking accuracy, particularly in addressing object misclassification. In the conducted study, the proposed method achieved average precision = 0.95.

  • Evaluation of a Small Inland Ferry’s Energy Requirements from the Acceleration Stage of Towing Tank Model Tests
    • Magdalena Kunicka
    • Klaudia Wrzask
    • Wojciech Litwin
    • Mirosław Grygorowicz
    • Hamid Zeratgaar
    2024 Pełny tekst Polish Maritime Research

    Computing the power required to meet a ship’s operational needs is one of the most important tasks in naval design. The power required to propel a vessel is directly related to the resistance the hull experiences as it moves through the water. The conventional method of determining a ship’s resistance involves towing tank tests of ship models at a fixed speed; however, for short-range vessels, where constant speed is not the primary mode of operation, a dynamic model is needed. This paper demonstrates a way in which different operational motion profile models can be retrieved from the acceleration stage of towing tank tests. We show that the data from the acceleration stage, often overlooked in towing tank tests, allow us to derive the gliding equations of motion. A dynamic model of a small inland ferry on the Motława River in the city of Gdańsk is developed, which enables optimisation of the required power based on different operation profiles.

  • Evaluation of high-frequency roughness measurement errors for composite and ceramic surfaces after machining
    • Przemysław Podulka
    • Wojciech Macek
    • Mirosław Szala
    • Andrzej Kubit
    • Kinkar Chandra Das
    • Grzegorz Królczyk
    2024 Pełny tekst Journal of Manufacturing Processes

    Precise characterisation of surface topography is of the greatest importance since many factors directly affect the accuracy of the whole measurement process. In this paper, the variety of surface topographies from machined composite and ceramic workpieces was studied with a special emphasis on the measurement results. Surfaces were subjected to the ground diamond, honing and milling processes. Measurement results were analysed in terms of the application of the procedure for the removal of the high-frequency noise. Bandwidth characteristics were supported by the studies of autocorrelation and power spectral functions. It was found, that examination of noisy data, especially its isotropic properties, is crucial in the enhancement of the noise-removal methods. The proposed procedure was validated through direction and profile characterisation. The spline filtering technique with a 7.5 μm cut-off was encouraged against other generally used filtering techniques for the reduction of high-frequency measurement noise considering the study based on the power spectral, autocorrelation and direction functions. The proposed methodology was validated by comparing it to the averaged results of 3 time repeated measurements of the composite and ceramic surfaces after machining. The main advantage of the proposal is reducing the time of data processing due to the fast and easy-to-implement usage of general surface topography analysis functions, available in the commercial software of the measuring instrument.

  • Evaluation of Selected Heavy Metal Contaminants as Well as Nitrates and Nitrites in the Microgreens of Nigella (Nigella sativa L.), Safflower (Carthamus tinctorius L.), and Camelina (Camelina sativa L.) at Different Stages of Vegetation
    • Joanna Kapusta-Duch
    • Sylwester Smoleń
    • Elżbieta Jędrszczyk
    • Teresa Leszczyńska
    • Barbara Borczak
    • Barbara Kusznierewicz
    2024 Applied Sciences-Basel

    Microgreens are a new, rapidly growing group of foodstuffs. The decorative function of these is often accompanied by their use in traditional dishes. As microgreens are eaten at very early stages, when the development of the epidermis is at its minimum, the bioavailability of minerals will be found to be higher in microgreens then in mature vegetables. So, microgreens can be an excellent functional food, especially for mineral-deficient populations, although they can also be a source of contaminants such as heavy metals or nitrates and nitrites. The purpose of this study was to measure the levels of selected heavy metals (i.e., cadmium, arsenic, lead, chromium, aluminium, zinc, copper, cobalt, molybdenum, manganese, vanadium, boron, antimony, thallium, titanium and strontium), as well as nitrates and nitrites, in microgreens at various stage of vegetation, using uncommon oilseed plants like nigella—Nigella sativa L., safflower—Carthamus tinctorius L., and camelina—Camelina sativa L. The examined microgreens of rare oilseed plants may be a source of contaminants and nitrates. The mineral profile of these plants is mainly determined by their genotype. Microgreens’ cultivation involves compliance with safety standards and replicable conditions to guarantee that the highest nutritional value is reached at the lowest possible contaminant level.

  • Evaluation of Terpene Decomposition in Kaffir Lime Juice during Storage Using Gas Chromatography–Mass Spectrometry and Proton Transfer Reaction–Mass Spectrometry
    • Martyna Lubinska-Szczygeł
    • Żaneta Polkowska
    • Bianka Tobolkova
    • Tomasz Majchrzak
    • Martin Polovka
    • Parichart Promchote
    • Shela Gorinstein
    2024 MOLECULES

    Kaffir lime juice, often treated as production waste, can be a good source of terpenes. These compounds undergo various decomposition processes under the influence of external factors, especially during transportation and storage. In this paper, it was possible to monitor changes in the terpene profile of kaffir lime juice under different storage conditions, namely, 4 ◦C, 20 ◦C, and 35 ◦C. The identification of key decomposition products was achieved using gas chromatography–mass spectrometry (GC–MS) and a data mining protocol. It was followed by tracing those products in different storage conditions using a high-throughput proton transfer reaction mass spectrometry (PTR–MS) approach. Based on our findings, degradation pathways were presented, showing that the main products resulting from storage are p-cymene, p-cymenene, terpinene-4-ol, and α-terpineol. It was shown that conversion to p-cymenene occurs after 5 days of storage. Terpinene-4-ol and α-terpineol were found to be the final products of the conversion at all temperatures. Changes in the composition of terpenes are important from the point of view of their bioactive properties.

  • Evaluation of the Effectiveness of Compression Therapy Combined with Exercises Versus Exercises Only Among Lipedema Patients Using Various Outcome Measures
    • Monika Czerwińska
    • Marcin Gruszecki
    • Jacek Rumiński
    • Rita Hansdorfer-Korzon
    2024 Life

    The treatment of lipedema remains challenging, largely due to widespread misconceptions. Selecting the appropriate treatment method necessitates the use of accurate outcome measures. This study aims to evaluate the effectiveness of compression therapy combined with exercises versus exercises alone in lipedema patients using various outcome measures. Twenty-four women with lipedema were divided into two equal groups: one group received compression therapy plus exercises while the other group performed exercises only. The effectiveness of the treatment was assessed before and after the intervention using several measures: an SF-36 questionnaire, a symptom severity survey, circumference (via 3D scanning), and body composition analysis. Significant improvements were observed in the SF-36 Physical Functioning and SF-36 Energy/Fatigue scores among participants in the compression group. Additionally, there was a reduction in the heaviness of extremities, the disproportion between the trunk and limbs, and the level of swelling in the compression therapy. Circumferences decreased in both groups. Although more circumferences were significantly reduced in the compression group, the reduction at the point above the knee was greater in the non-compression group. Compression therapy is an effective treatment for lipedema. Various measures, such as quality-of-life questionnaires and symptom severity surveys, can be used as valuable tools for assessing the effectiveness of lipedema treatment.

  • Evolution of charge density wave order in continuous solid solutions Lu(Ni1-xCox)C2
    • Herwig Michor
    • Marta Roman
    • Lisa Reisinger
    • Maria Fritthum
    • Jana Schmelzenbart
    • Alexander Vock
    • Volodymyr Levytskyi
    • Volodymyr Babizhetskyy
    • Bogdan Kotur
    2024 Pełny tekst JOURNAL OF ALLOYS AND COMPOUNDS

    Pseudo-ternary solid solutions, Lu(Ni1-xCox)C2 (0 ≤ x ≤ 1), were studied by means of powder X-ray diffraction, differential thermal analysis as well as electrical resistivity and heat capacity measurements. The crystal structure of the Lu(Ni1-xCox)C2 series, as investigated by means of X-ray powder diffraction, is of structure type CeNiC2, space group Amm2, Pearson symbol oS8. The structural analysis reveals a non-monotonous evolution, in particular for the a- and c-lattice parameters, resulting in a non-linear decrease of the unit cell volume, markedly deviating from Vegard’s rule, due to non-isoelectronic substitution of Ni by Co. Utilizing differential thermal analysis (DTA) data, a pseudo-binary phase diagram LuNiC2–LuCoC2 has been constructed. The evolution of charge density wave order in Lu(Ni1-xCox)C2, which reaches an ordering temperature TCDW ≅ 450 K for LuNiC2, was studied by means of electrical resistivity and heat capacity measurements. For solid solutions prepared via the floating-zone melting technique it became feasible to trace charge density wave (CDW) features of the temperature dependent electrical resistivity, thus, indicating a critical composition for the suppression of CDW order in Lu(Ni1-xCox)C2 at around x ≈ 0.15 – 0.17, which matches with a distinct drop of the composition dependent electronic Sommerfeld coefficient of the low temperature heat capacity of Ni-rich solid solutions.

  • Ewolucja zawodu nauczycielskiego. Od klasycznej szkoły do nowych wyzwań.
    • Aneta Sobiechowska-Ziegert
    • Katarzyna Kubiszewska
    2024 Refleksje. Kwartalnik Zachodniopomorskiego Centrum Doskonalenia Nauczycieli

    Zawód nauczyciela od zawsze był traktowany jako fundament społeczeństwa, kształtujący umysły i charaktery przyszłych pokoleń. Jednakże w dzisiejszym, dynamicznym świecie ranga i rola nauczyciela ulegają znaczącym przemianom. W związku z postępującą digitalizacją, zmianami w sposobie przyswajania wiedzy przez młodych ludzi oraz ewoluującymi potrzebami edukacyjnymi, zawód nauczyciela staje w obliczu nowych zagrożeń, ale również oferuje szereg niezaprzeczalnych szans. W niniejszym artykule przyjrzymy się wyzwaniom oraz możliwościom, jakie niesie Edukacja 4.0 dla zawodu nauczyciela, ze szczególnym uwzględnieniem aspektów związanych z tutoringiem, budowaniem relacji z uczniami oraz wspieraniem ich w osiąganiu celów naukowych i rozwojowych.

  • Example of Using Particle Swarm Optimization Algorithm with Nelder–Mead Method for Flow Improvement in Axial Last Stage of Gas–Steam Turbine
    • Paweł Ziółkowski
    • Łukasz Witanowski
    • Stanisław Głuch
    • Piotr Klonowicz
    • Michel Feidt
    • Aimad Koulali
    2024 Pełny tekst ENERGIES

    This article focuses principally on the comparison baseline and the optimized flow efficiency of the final stage of an axial turbine operating on a gas–steam mixture by applying a hybrid Nelder– Mead and the particle swarm optimization method. Optimization algorithms are combined with CFD calculations to determine the flowpaths and thermodynamic parameters. The working fluid in this study is a mixture of steam and gas produced in a wet combustion chamber, therefore the new turbine type is currently undergoing theoretical research. The purpose of this work is to redesign and examine the last stage of the gas–steam turbine’s flow characteristics. Among the optimized variables, there are parameters characterizing the shape of the endwall contours within the rotor domain. The values of the maximized objective function, which is the isentropic efficiency of the turbine stage, are found from the 3D RANS computation of the flowpath geometry changing during the improvement scheme. The optimization process allows the stage efficiency to be increased by almost 4 percentage points. To achieve high-quality results, a mesh of over 20 million elements is used, where the percentage error in efficiency between the previous and current mesh sizes drops below 0.05%.

  • Excitation of Circularly Polarized Wave via Single-Feed Metasurface-Integrated Compact Antenna for Internet of Things
    • Shahanawaz Kamal
    • Ullah Ubaid
    • Sławomir Kozieł
    2024 AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS

    A compact circularly polarized (CP) quasi-omnidirectional antenna is introduced for internet of things (IoT). The structure consists of two components implemented on FR-4 substrates, and sep-arated by an air gap: one printed with a rectangular patch fed through a matching network, and another with a metasurface and a ground plane. Two different methods for impedance matching are employed. An equivalent circuit model of the antenna is developed to facilitate the analysis. The design procedure, operating principle, and experimental validation of the antenna are de-scribed. The optimized antenna occupies 0.3λ × 0.1λ footprint and 0.04λ height at 16 GHz and exhibits the impedance bandwidth of ∼2 GHz, axial ratio of <3dB, realized gain of 6 dBi and efficiency of ~80%.

  • Excitation of the Secondary Modes by the Broad Spectrum Sound in a Liquid with Relaxation Losses
    • Anna Perelomova
    2024 Pełny tekst Archives of Acoustics

    Features of nonlinear phenomena and, in particular, acoustic excitation of the entropy and relaxation modes in a liquid electrolyte with a chemical reaction are examined. The total range of frequencies of an exciter is considered, and the instantaneous dynamic equations are derived which govern perturbations in the secondary modes. The instantaneous leading-order acoustic forces of the secondary modes are evaluated. Examples of harmonic and nearly harmonic acoustic exciter are considered in detail. The difference in the nonlinear acoustic phenomena in an electrolyte and gases with relaxation mechanisms are specified and discussed.

  • Excitation of Waves in a Dispersive Medium. Example of Flow of a Bubbly Liquid
    • Anna Perelomova
    2024 Pełny tekst ACTA PHYSICA POLONICA A

    The excitation of wave motion by an external source and the interaction of modes inherent to a ow in a dispersive medium are considered. Dispersion is caused by the presence of gaseous bubbles in a liquid. A large variety of steady excited waveforms is possible when the exciting wave is also steady and propagates at a constant velocity. The velocities of the exciter and forced waves may be dierent. This leads to a variety of non-stationary excitations

  • Expedited Machine-Learning-Based Global Design Optimization of Antenna Systems Using Response Features and Multi-Fidelity EM Analysis
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    • Leifur Leifsson
    2024

    The design of antenna systems poses a significant challenge due to stringent per-formance requirements dictated by contemporary applications and the high com-putational costs associated with models, particularly full-wave electromagnetic (EM) analysis. Presently, EM simulation plays a crucial role in all design phases, encompassing topology development, parametric studies, and the final adjustment of antenna dimensions. The latter stage is especially critical as rigorous numerical optimization becomes essential for achieving optimal performance. In an increas-ing number of instances, global parameter tuning is necessary. Unfortunately, the use of nature-inspired algorithms, the prevalent choice for global design, is hin-dered by their poor computational efficiency. This article presents an innovative approach to cost-efficient global optimization of antenna input characteristics. Our methodology leverages response feature technology, ensuring inherent regulariza-tion of the optimization task by exploring the nearly-linear dependence between the coordinates of feature points and the antenna's dimensions. The optimization process is structured as a machine learning (ML) procedure, utilizing a kriging surrogate model rendering response features to generate promising candidate de-signs (infill points). This model is iteratively refined using accumulated EM simulation data. Further acceleration is achieved by incorporating multi-fidelity EM analysis, where initial sampling and surrogate model construction use low-fidelity EM simulations, and the ML optimization loop employs high-fidelity EM analysis. The multi-fidelity EM simulation data is blended into a single surrogate using co-kriging. Extensive verification of the presented algorithm demonstrates its remarkable computational efficiency, with an average running cost not exceed-ing ninety EM simulations per run and up to a seventy percent relative speedup over the single-fidelity procedure.

  • Expedited Re-Design of Multi-Band Passive Microwave Circuits Using Orthogonal Scaling Directions and Gradient-Based Tuning
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    • Ubaid Ullah
    2024 Pełny tekst Scientific Reports

    Geometry scaling of microwave circuits is an essential but challenging task. In particular, the employment of a given passive structure in a different application area often requires re-adjustment of the operating frequencies/bands while maintaining top performance. Achieving this necessitates utilization of numerical optimization methods. Nonetheless, if the intended frequencies are distant from the ones at the starting point, local search procedures tend to fail, whereas global search algorithms are computationally expensive. As recently demonstrated, a combination of large-scale concurrent geometry parameter scaling with intermittent local tuning allows for dependable re-design of high-frequency circuits at low CPU costs. Unfortunately, the procedure is only applicable to single-band structures due to synchronized modifications of all operating bands under scaling. This article discusses a novel procedure that leverages a similar overall concept, but allows for independent control of all center frequencies. To achieve this goal, an automated decision-making procedure is developed in which a set of orthogonal scaling directions are determined based on their effect on individual circuit bands, and using auxiliary optimization sub-problems. The scaling range is then automatically computed by solving and appropriately-defined least-square design relocation problem. The methodology introduced in the work is illustrated using two planar passive devices. In both cases, wide-range operating frequency re-design has been demonstrated and favorably compared to conventional gradient-based tuning. Furthermore, the presented procedure has been shown to be computationally efficient. It is also easy to implement and integrate with a variety of gradient-based optimization procedures of a descent type.

  • Experimental and Numerical Investigations of the Effect of Curing Conditions on the Temperature Rise of Concrete
    • Aleksandra Kuryłowicz-Cudowska
    2024 Pełny tekst International Journal of Civil Engineering

    This paper presents experimental and numerical studies investigating the impact of three curing conditions on temperature evolution in concrete cubes. The tests were performed on samples of the same volume (3.375 dm3) under different curing conditions: room temperature, insulation boxes, and adiabatic calorimeter. Various cements (Portland cement, Portland composite cement, and blast furnace slag cement) and aggregates (gravel and basalt) were examined. The temperature evolution for all mixtures was analyzed, revealing a correlation between temperature increase and concrete type. Under insulation and adiabatic curing, Portland cement with gravel aggregate exhibited the highest temperature rise, while blast furnace slag cement with basalt aggregate showed the lowest increase. The incorporation of slag, ash, or other mineral additives reduced temperature rise. Additionally, basalt aggregate’s higher heat capacity and thermal energy accumulation led to a decreased temperature increase compared to gravel. Using recorded thermal data, a numerical procedure predicting temperature development in nonadiabatic conditions through direct adiabatic tests is proposed. Comparisons between experimental and numerical temperature evolutions confirmed the model’s accuracy.

  • Experimental and numerical studies on the mechanical response of a piezoelectric nanocomposite-based functionally graded materials
    • Mohammad Malikan
    • Magdalena Rucka
    2024

    This work presents an experimental study of piezoelectric structures reinforced by graphene platelets, based on the concept of the functionally graded materials (FGMs). The assumed model is a rectangular beam/plate and the composition is due to the Halpin-Tsai rule. The model is also simulated in the Abaqus software which is the first time that such a structure has been modelled in an FEM package. In addition, a mathematical model based on a beam/plate theory, Lagrangian strains and variational technique is expressed and the derived partial differential equations governing the mechanics of the structure are solved numerically using the differential quadrature method. In terms of the experiments, the nanocomposite is fabricated in the form of layered FGMs using powder metallurgy. The specimens are subjected to two mechanical tests, bending and tensile. To accurately identify the FGM sample cross-section, a scanning electron microscope is used to examine the microstructure of the solid.

  • Experimental and numerical study of thermal and electrical potential of BIPV/T collector in the form of air-cooled photovoltaic roof tile
    • Jakub Łukasik
    • Jan Wajs
    2024 Pełny tekst INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

    Among renewable energy sources, Building-Integrated Photovoltaic/Thermal (BIPV/T) systems are gaining increasing interest. To improve their economic competitiveness, technologies that increase their efficiency are searched for. The paper is devoted to evaluating the impact of various air-cooling configurations on the thermal and electrical performance of a photovoltaic roof tile. A numerical model of the own experimental system was developed in the ANSYS Fluent software for a wide range of input variables. The original approach based on the SST k-ω turbulence model, Discrete Ordinates radiation model, and the use of Solar Load module were proposed. Such a numerical model allows representation of semi-transparent layers and variable solar irradiance, which is a unique realization of real system modelling. Numerous analyses conducted indicate a higher heat recovery potential for an airflow duct with a height of 25 mm for all configurations analysed. The highest value of recovered heat flux was approximately 330 W/m2 under conditions of a volumetric air flow rate of 7.5 m3/h and solar irradiance equal to 900 W/m2. Good agreement of the results of the multivariant CFD simulations with new experimental ones was confirmed. Insight into the flow phenomena behind the achieved thermal results supplemented the knowledge. The highest electrical efficiency obtained experimentally was 5.76 % for a channel with a height of 50 mm, volumetric flow rate equal to 7.5 m3/h and solar irradiance equal to 600 W/m2. The presented methodology and the results obtained can be useful in research devoted to optimising BIPV/T air-based cooling systems, which will then be tested in-situ. Moreover, new experimental data collection can be used for the verification of numerical models.

  • Experimental and numerical study on stability loss of innovative geometry steel girder
    • Małgorzata Gordziej-Zagórowska
    • Wojciech Migda
    • Natalia Lasowicz
    • Patryk Deniziak
    • Alicja Bera
    • Jakub Kowalski
    2024 JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH

    This paper presents the experimental and numerical analysis of an innovative plate girder geometry with variable web thicknesses. An idea proposed in this research is to increase the stability of the girder web by increasing its thickness in the compressed zone. This solution can replace commonly used longitudinal stiffeners which are designed to prevent web local loss of stability. Moreover, such an innovative approach requires only one addi- tional butt weld along the entire element, which is technologically a simpler, cheaper and faster operation (due to the possibility of full automation of production) compared to manual welding of individual stiffeners. The experimental and numerical study shows that application of a web with variable thickness in I-shaped plate girder geometry subjected to four-point bending results in a change in failure mechanism from local to global one. Moreover plate girders with single and double-sided longitudinal stiffeners have been tested numerically. The result of the study clearly shows that values of ultimate load estimated for plate girders with longitudinal stiffeners were smaller than those obtained for innovative ones. It confirms that the proposed solution may prevent web from local stability loss and increase plate girder stability due to bending. This innovative method can be also considered as an effective procedure of strengthening the web in its compressive zone compared to commonly used longitudinal stiffeners

  • Experimental and theoretical study on high-temperature creep of VT6 titanium alloy under multi-axial loading conditions
    • Leonid Igumnov
    • Ivan Volkov
    • V.a. Kazakov
    • Denis Shishulin
    • Ivan Modin
    • Alexander Belov
    • Victor Eremeev
    2024 JOURNAL OF THERMAL STRESSES

    In the framework of damage mechanics, we discuss a new mathematical model that describes the kinetics of the stress–strain state and damage accumulation during material degradation by the mechanism of long-term strength under complex multiaxial stress state. An experimental and theoretical technique is proposed for determination of material parameters and scalar constitutive functions for damaged media based on specially set experiments on laboratory specimens. The results of experimental studies and numerical simulations of short-term high-temperature creep of VT6 titanium alloy under uniaxial and multiaxial loading are presented. Numerical results are compared with the data obtained through experiments. Particular attention is paid to simulating the process of unsteady creep for complex deformation modes, accompanied by rotation of main areas of stress, strain and creep strain tensors. It is shown that the developed version of the constitutive relations of the damaged media enables us to describe the processes of unsteady creep and long-term strength of structural alloys under multiaxial stress with the accuracy sufficient for engineering calculations.

  • Experimental investigation of thermal energy storage in shell-and-multi-tube unit with nano-enhanced phase change material
    • Maciej Fabrykiewicz
    • Janusz Cieśliński
    2024 APPLIED THERMAL ENGINEERING

    This paper deals with thermal energy storage with use of nanoparticle enhanced phase change material in shell-and-multitube unit. The experiments are conducted under atmospheric pressure. Paraffin wax and two different fatty acids are used as base phase change material. Graphite and multi-walled carbon nanotubes serve as nanoparticles. Graphite nanoparticles are tested at the concentrations of 0.1%, 1% and 5% by weight, while multi-walled carbon nanotubes only at 0.1%wt. Ultrasonic vibration and homogenizer are used in order to stabilize the dispersion of the nanoparticles. Polyvinylpyrrolidone surfactant is used to stabilize the suspension and the tested nano-enhanced phase change material exhibit satisfactory stability. Experimental measurements are performed for a bundle of 7 tubes with outside diameter of 6 mm in a staggered arrangement and a pitch ratio of 4.5. It is found that, regardless of the tested base phase change material, the addition of graphite nanoparticles with mass concentration of 0.1% does not significantly affect the charging and discharging times compared to base phase change material. The differences in charging and discharging times did not exceed 11%. For a graphite nanoparticles mass concentration of 5%, an increase in the charging time by up to 21% and a reduction in the discharging time by 24% was observed, depending on the type of base phase change material. An addition of multi-walled carbon nanotubes with mass concentration of 0.1% shows an increase in charging time regardless of the type base phase change material up to 144% with negligible influence on the discharging time. It was also observed that adding a surfactant to the produced nano-enhanced phase change material results in a reduction in charging time by up to 83% depending on the type of base phase change material.

  • Experimental investigation on heat pipes supported by soy wax and lauric acid for electronics cooling
    • Paweł Szymański
    • Radosław Paluch
    2024 Journal of Energy Storage

    This paper presents an experimental study of heat pipes for electronics cooling that were supported by energy storage materials (i.e. phase change materials - PCMs) coated at the adiabatic section. The PCMs utilized included two materials, namely lauric acid and soy wax, the latter being considered as a more cost-effective alternative. The study focused on three different powers: 20 W, 25 W, and 30 W. Both heating, cooling, and thermal cycling experiments were performed in order to compare the thermal performance of cooling units. The experimental results showed that the incorporation of lauric acid as a thermal energy storage material reduced the maximum temperature by 11.6 %, 14.6 %, and 14.5 % for the examined powers. On the other hand, the utilization of soy wax resulted in temperature reductions of 4.3 %, 6.3 %, and 6.8 %. Furthermore, it was observed that lauric acid could store 25 % of the energy during the maximum power dissipation test, whereas soy wax could store 12 %. It was shown that lauric acid improved the thermal performance of the unit by approximately twice as effectively as soy wax. However, it is noteworthy that soy wax exhibits a significantly lower cost, making it a potentially viable alternative for less demanding applications where cost considerations are crucial.

  • Experimental investigations on water sorptivity in mortars with the use of X-ray micro-CT system.
    • Łukasz Skarżyński
    • Andrzej Tejchman-Konarzewski
    2024 CONSTRUCTION AND BUILDING MATERIALS

    W pracy doswiadczalnej zbadano zjawisko sorpcji wody w pryzmatycznych próbkach zapraw, które jest ściśle powiązane z trwałością materiału. Sorpcyjność oceniana na etapie ustalonym w połączeniu z warunkami zewnętrznymi może być wykorzystana do przewidywania okresu użytkowania. Sorpcyjność początkową i wtórną wody w próbkach zapraw nienasyconych zmierzono w badaniach laboratoryjnych zgodnie z normą amerykańską ASTM C 1585–04. Wpływ porowatości początkowej na sorpcyjność zbadano poprzez zmianę stosunku cementu do piasku (c/s) i stosunku wody do cementu (w/c). Dodatkowo zmieniono powierzchnię napływu wody, która miała orientację pionową lub poziomą. Nowością była wizualizacja rozkładu wody w badanych próbkach za pomocą aparatu rentgenowskiego mikro-CT 3D SkyScan 1173. Stwierdzono, że na sorpcyjność zaprawy silnie reaguje współczynnik c/s, wahający się do 100%, przy czym umiarkowany wpływ na nią ma współczynnik w/c zmieniający się aż do 25% i powierzchnia napływu wody zmienny od 25% do 45%. Sorpcyjność wzrastała wraz ze spadkiem współczynnika c/s (zgodnie z istniejącymi danymi literaturowymi) i stosunku w/c (w przeciwieństwie do istniejących danych literaturowych). Na podstawie zdjęć mikro-CT stwierdzono, że rozkład wody w próbkach zapraw był nierównomierny, a ich większa porowatość wpływała na wzrost poziomu wody, ale nie na całkowitą objętość pochłoniętej wody (w przeciwieństwie do danych literaturowych). Do odrywania cząstek wody doszło przed jej głównym frontem.

  • Experimental observations on the creep behaviour of frozen soil
    • Katarzyna Staszewska
    • Andrzej Niemunis
    • Marcin Cudny
    2024 Acta Geotechnica

    Constitutive models in the literature for creep of frozen soil are based on the direct use of time counted from the onset of creep. An explicit time dependence in a constitutive equation violates the principles of rational mechanics. No change in stress or temperature is allowed for during creep, using the time-based formulations. Moreover, the existing descriptions need much verification and improvement on the experimental side as well. Creep behaviour of artificially frozen sand was evaluated experimentally. Novel testing methods were used, and new insights into the creep behaviour of frozen soil were gained. Creep rate under uniaxial compression was examined with different kinds of interruptions, like unloadings or overloadings. Experimental creep curves were presented as functions of creep strain. They were brought to a dimensionless form which describes the creep universally, despite changes in stress or temperature. Possible anisotropy of frozen soil was revealed in the creep tests on cubic samples with changes of the loading direction. Using the particle image velocimetry (PIV) technique, information on the lateral deformation and the uniformity of creep were obtained. Volumetric creep of unsaturated frozen soil under isotropic compression was demonstrated to be due to the presence of air bubbles only.

  • Experimental study and numerical simulation on porosity dependent direct reducibility of high-grade iron oxide pellets in hydrogen
    • Behzad Sadeghi
    • Pasquale Cavaliere
    • Mutlucan Bayat
    • Niloofar Ebrahimzadeh Esfahani
    • Aleksandra Laska
    • Damian Koszelow
    2024 Pełny tekst INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

    The transition to more environmentally friendly steel production methods has intensified research into hydrogen-based direct reduction (HyDR) of iron oxide pellets. The aim of this study is to systematically investigate the kinetics of the reduction process, the evolution of porosity and the resulting microstructural changes on the reduction behavior of high-quality pellets during HyDR of iron ore at different temperatures. A modified mathematical model is developed based on the shrinkage kernel model, taking into account both mass and heat transport in a hydrogen atmosphere. The effects of temperature, particle size and time on the reduction behavior of the pellets are investigated. The simulated results are validated and discussed by the results of a batch of iron oxide pellets consisting of ten almost spherical pellets subjected to the direct reduction process with pure hydrogen. The results show that the total energy input to the HyDR process is a complex balance of factors, including chemical reaction rates, diffusion dynamics and entropy generation. The increase in free volume and simultaneous decrease in pore diameter reflect the dynamic nature of the microstructure, which includes additional free volume and defects due to the volume discrepancies and associated stresses between the reactant and product phases. Furthermore, the data show that higher temperatures accelerate the reduction reactions, especially the transformation of wustite into metallic iron. This phase transition is characterized by a significant volume change that cannot be accommodated by elastic deformation alone, leading to the development of lattice defects such as cracks, creep pores and dislocations that serve as stress relief mechanisms. The trends for porosity change at 950 °C and 1000 °C observed in the experimental results are correct and in good agreement with the numerical and simulated results.

  • Experimental study of the impact of notches and holes made in the front edge of adherends on the properties of static and fatigue strength of adhesive joints
    • Andrzej Kubit
    • Wojciech Macek
    • Władysław Zielecki
    • Paulina Szawara
    • Piotr Myśliwiec
    2024 INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES

    The paper presents the results of experimental studies aimed at determining the effect of holes and notches at the front edge of adherends on the strength of adhesive joints. Single-lap joints made of S235JR steel sheets joined with Araldite 2014-2 epoxy adhesive were tested. Comparative tests of static strength in the shear test as well as high-cycle fatigue strength tests were carried out. Joints with three holes with a diameter of 3 mm filled with adhesive and notches 3 mm wide and 4 mm long also filled with adhesive were tested and compared with reference joints, i.e. without modification. The assumption was that the structural changes applied were to contribute to the reduction of the peak of peel and shear stresses that typically occur in this type of joint. Based on the static strength tests, no significant effect of the applied modifications on the strength of the connections was demonstrated. However, in the case of fatigue strength, a significant improvement in fatigue lifetime was demonstrated, which in the area of low cycle fatigue increased by 328.6 % for the joint with notches and by 640.8 % for the variant with holes. For the fatigue fracture surfaces, a topography analysis was carried out by determining the roughness parameters. Significant differences were exposed since at the leading edge, the selected parameters were significantly lower for the reference variant than for variants with notches and holes.

  • Experimental study of the multi-disc negative brake for a hydraulic motor
    • Paweł Śliwiński
    • Ryszard Jasiński
    2024

    This paper describes the methodology for experimental testing of a multi-disc brake. The construction of this brake was also present. The brake is dedicated to hydraulic motors with a small working volume. Experimental tests were carried out on a brake with plates immersed in oil and, for comparison, tests were carried out on a dry brake. As a result of the tests, the permissible torque (load) that is able to transfer the brake and the pressure required to release the brake were determined. The temperature rise in the chamber of the uncoupled brake (both wet and dry brake), whose shaft with active discs was rotated at speed of 1,500 rpm, was also examined. The influence of the deformation of the brake discs on the characteristics of the torque of friction in these discs was also observed.

  • Experimental study on the feasibility of alternative materials for tilting pad thrust bearings operating in transition to mixed friction
    • Michał Wasilczuk
    • Michał Wodtke
    2024 Pełny tekst Friction

    In hydrodynamic bearings traditional bearing alloys: Babbitts and bronzes are most frequently utilized. Polymer sliding layers are sometimes applied as a valuable alternative. Hard diamond-like carbon (DLC) coatings, which are also considered for certain applications may show some advantages, as well. Although material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions, which is crucial for bearings with frequent starts and stops. Experimental research aimed at studying the performance of fluid film bearings in the specific operating regime, including the transition to mixed friction, is described in the paper. The tests were carried out on four tilting pad bearings of different material compositions: Steel/bronze, DLC/steel, steel/polyether ether ketone (PEEK), and steel/Babbitt. The tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values, and observing the changes of friction force during the transition to mixed friction regime. Analysis of the transition conditions and other results showed clear differences between the tested bearings, illustrating the feasibility of less popular material compositions for bearings operating in specific conditions. More specifically, the DLC/steel bearing was demonstrating superior performance, i.e. lower friction, transition to mixed friction occurring at higher load, and more stable performance at start-stop regime over the other tested bearings.

  • Experimental test results of an automatic voltage regulator with independent phase voltage controllers
    • Wojciech Śleszyński
    • Artur Cichowski
    • Krzysztof Jakub Szwarc
    • Robert Małkowski
    • Paweł Szczepankowski
    • Andrzej Augusiak
    • Dariusz Karkosiński
    • Ryszard Strzelecki
    2024 Pełny tekst Bulletin of the Polish Academy of Sciences-Technical Sciences

    The growing number of distributed renewable energy sources and dynamic constant-power loads (e.g. electric vehicle charging stations) pose new challenges for network operators. These changes result in alterations to network load profiles and load flows, leading to greater voltage volatility. One effective solution to these problems can be the use of automatic voltage regulators (AVRs), which stabilize and symmetrize voltage output, whether at distribution transformers (DTs) or elsewhere in the distribution network. The device developed by the authors consists of two bidirectional power converters and three single-phase transformers connected in series to the low-voltage grid as a stabilizer. The proposed control system provides accurate and fast regulation of the AVR’s output voltage (within the range of ±10% of the nominal grid voltage), with each phase being independently adjusted, regardless of the type of power load. The article includes test results demonstrating selected functionalities of the developed AVR. The physical model of the device discussed in the article is a research componentof the LINTE2 laboratory of the Gda´nsk University of Technology

  • Experimental tests of selected damping and sound-absorbing materials to determine their suitability for sound attenuation of hydroacoustic measuring tank
    • Aleksander Schmidt
    • Lech Kilian
    • Jacek Marszal
    2024 Pełny tekst Vibrations in Physical Systems

    The article contains a description and results of the measurements necessary to select the optimal material for damping two hydroacoustic measuring tanks according to simple suitability criteria, i.e. obtaining minimal sound reflections from the water surface, walls and bottom in these pools by covering the surfaces with sound-dispersing materials or acoustic absorbers. One will be larger (15x10x10 m) for measurements in the range of possibly low ultrasound frequencies and the other smaller (4x3x3 m). The frequency characteristics of these materials, but also the price, ease of assembly and cleaning, and ageing, are decisive for their usefulness. Attractive (according to these criteria) patches of ‘synthetic grass’ and plates made of various plastics were selected for the measurements. The obtained results were compared with the measurement results of the long-used curtains made of dissipative brushes for dampening the measuring tank of the Department of Sonar Systems (DSS) and with those presented by a specialized manufacturer of commercial absorption plates.

  • Experimental tests of steel double-type balcony connections
    • Maciej Tomasz Solarczyk
    • Paweł Michał Piotrkowski
    • Maciej Niedostatkiewicz
    2024 Pełny tekst Czasopismo Techniczne

    The paper presents analysis and results of experimental tests of full scale prefabricated balcony sets with dimensions (width × length × height): 2.0 m × 2.78 m × 0.186 m (in slope to 0.17 m). The sets consists of reinforced concrete slabs (balcony and ceiling) connected with each other by double-type balcony connections. The paper analyses the impact of variable parameters on the load carry capacity of elements. Additionally an overview of current scientific and technical papers in the field of balcony connections is provided.

  • Experimentally Aided Operational Virtual Prototyping to Predict Best Clamping Conditions for Face Milling of Large-Size Structures
    • Krzysztof Kaliński
    • Marek Galewski
    • Michał Mazur
    • Natalia Stawicka-Morawska
    2024 Applied Sciences-Basel

    Vibrations occurring during milling operations are one of the main issues disturbing the pursuit of better efficiency of milling operations and product quality. Even in the case of a stable cutting process, vibration reduction is still an important goal. One of the possible solutions to obtain it is selection of the favorable conditions for clamping the workpiece to the machine table. In this paper, a method for predicting and selecting the clamping condition of a large-size workpiece for the reduction in vibrations during milling is presented. A modal test of the workpiece is performed first for a selected set of tightening screw settings. Next, one milling pass is performed to obtain reference data which are then used to tune the hybrid computational model. In the subsequent step, milling simulations are performed for a set of tightening variants, and the best one is selected, providing the lowest vibrations, assessed as the root mean square (RMS) of vibration displacements. In this paper, the description of the clamping selection procedure, key elements of the simulation model, and simulation and experimental results obtained for the milling of the test workpiece performed for a set of different clamping conditions are provided. The proposed method accurately predicts not only the best but also the worst clamping conditions.

  • Expermental investigation on adsorption of methylene blue dye from waste water using corncob cellulose-based hydrogel
    • Samuel Latebo Majamo
    • Temesgen Amibo
    • Dereje Tadesse Mekonnen
    2024 Pełny tekst Scientific Reports

    Hydrogel from corncob cellulose was synthesized in this investigation. The synthesized Hydrogel was characterized by SEM, XRD, and FTIR instruments. As the results indicate the synthesized hydrogel has required and important features, these suggest the suitability of hydrogel for the adsorption of methylene blue dye (MBD). Three important process variables (dosage, contact time, and initial concentration) with three levels were studied during the adsorption process at 30 °C and neutral pH. The efficiency of hydrogel for adsorption of MBD was determined in each experiment. The experimental results were statistically analyzed and interpreted. The maximum removal efficiency was achieved at 2.22 g/L of dosage, 80.36 min of contact time, and 74.54 mg/L of initial concentration. At this condition, 98.25% of MBD was achieved through experimental tests. Kinetics, isotherm, and thermodynamics studies were performed. Langmuir isotherm is more suitable to describe the adsorption process and the Pseudo second-order kinetic model fits this process. From the thermodynamics studies, all negative values of change in Gibbs free energy (ΔG°), and positive value of change in enthalpy (ΔH°), and change in entropy (ΔS°) indicate that the carried out experimental process is a spontaneous and endothermic. Moreover, the regeneration experiment for adsorbent was performed. The treatment of real textile industry waste water was conducted and the removal efficiency of hydrogel was 64.76%. This removal percentage reduction from sythetic aqueous solution is due to involvement of other pollutants in the real waste water. The synthesized hydrogel adsorbent is suitable up to the third cycle without significant loss in removal efficiency.

  • Exploring avian exposure to parent polycyclic aromatic hydrocarbons (PAHs): Using the common eider Somateria mollissima in a global context
    • Aneta Pacyna-Kuchta
    • Juliana Souza-Kasprzyk
    • Svend Erik Garbus
    • Igor Eulaers
    • Christian Sonne
    • Dariusz Jakubas
    2024 Pełny tekst SCIENCE OF THE TOTAL ENVIRONMENT

    Compared to other organic contaminants, birds are rarely studied for their exposure to polycyclic aromatic hydrocarbons (PAHs), mainly due to their effective metabolization of parent PAHs. However, as some studies suggest, exposure to PAHs may result in adverse health effects including decreased survival, especially following oil spills. In the present study, we analyzed samples from a sea duck, the common eider Somateria mollissima including feathers, preen oil, blood, liver and bile, to evaluate whether non- lethally collected samples could be reliably used for avian biomonitoring strategies. Phenanthrene was the only individual PAH detected across sample types, with the highest concentration found in preen gland and the lowest in blood. Significant differences in concentrations were observed between bile vs preen gland and liver vs preen gland, while for most compounds neither blood nor feathers showed detectable levels of parent PAHs. Therefore, the utility of those sample types for PAH exposure assessment may be limited and should be interpreted with caution, moreover as several physiological factors may affect them. Additionally, we also provide a comparison with the available literature to review current avian PAH exposure assessment and outline future research focused needs.

  • Exploring Cause-and-Effect Relationships Between Public Company Press Releases and Their Stock Prices
    • Filip Grzonkowski
    • Paweł Weichbroth
    2024

    The aim of the work is to design and implement a method of exploring the cause-and-effect relationships between company announcements and the stock prices on NASDAQ stock exchange, followed by a brief discussion. For this purpose, it was necessary to download the stock quotes of selected companies from the NASDAQ market from public web sources. Additionally, media messages related to selected companies had to be downloaded, and then a news sentiment analysis mechanism had to be prepared. The mechanism of sentiment analysis was prepared based on the supervised machine learning approach. The implemented method was used to analyze the sentiment of a set of stock exchange announcements and it was correlated with changes in the share prices of selected companies. Based on the collected data, the association rules were extracted using the Apriori algorithm. While the obtained results are very promising, however, one should also estimate the rate of return for the interrelated transactions to determine the true and ultimate value of discovered relationships.

  • Exploring hydrogen energy systems: A comprehensive review of technologies, applications, prevailing trends, and associated challenges
    • Muhammad Kamran
    • Marek Turzyński
    2024 Journal of Energy Storage

    Exploring hydrogen energy and its associated technologies is a pivotal pathway towards achieving carbon neutrality. This article comprehensively reviews hydrogen production technologies, storage technologies, and end-use applications of hydrogen, based on the input energy source, operating conditions, conversion efficiency, energy density, and unit investment cost. The review also highlights the advantages, disadvantages, and technological readiness of hydrogen production technologies, and storage methods. The selected hydrogen production methods include pyrolysis, gasification, fermentation, biophotolysis, electrolysis, thermolysis, and photolysis, while the selected hydrogen storage technologies are compressed, liquid, cryo-compressed, adsorption, and hydrides. Water electrolysis, highly efficient at 55–80 % and versatile, comes with a higher cost of $4.15–$10.30/kg. In contrast, pyrolysis offers more cost-effective solutions with moderate efficiency (35–50 %) and a reasonable yield (25–65 g/kg), making it suitable for budget-sensitive projects. Compressed, liquid, and cryo-compressed hydrogen offer high efficiency with the added benefit of compact storage due to their high volumetric and gravimetric densities. Metal and chemical hydrides provide excellent safety and efficiency, with metal hydrides also delivering high volumetric density for more compact solutions. Furthermore, the review explores the applications of hydrogen energy in renewable energy systems, support to existing grid, transportation, cogeneration and tri-generation, and metallurgy along with insights from pilot projects. Moreover, the article examines the challenges and opportunities encountered in hydrogen production, storage methods, and end-use applications. Finally, the article conducts a SWOT analysis, pinpointing key aspects crucial for the successful adoption of hydrogen in the future. The conclusions indicate that ongoing efforts in performance enhancement, scaling up, and technical advancements are essential to establish a cost-effective hydrogen economy.

  • Exploring Mechanism of Corrosion Inhibition of WE43 and AZ31 Alloys by Aqueous Molybdate in Hank’s Solution by Multisine Impedimetric Monitoring
    • Maria Osipenko
    • Jakub Karczewski
    • Michał Dominów
    • Marta Prześniak-Welenc
    • Jacek Gurgul
    • Irina Kurilo
    • Jacek Ryl
    • Dmitry Kharitonov
    2024 CORROSION SCIENCE

    The concept of utilizing multisine dynamic electrochemical impedance spectroscopy to monitor effectiveness of a model molybdate inhibitor for AZ31 and WE43 Mg alloys is proposed. The corrosion kinetics and instantaneous values of inhibition efficiency (IE) of molybdate at concentrations up to 150 mM were examined. The inhibitor provides inhibition in Hank’s solution at concentrations starting from ca. 25 mM, with the IE of about 90%. These data together with results of the surface analysis allowed to propose the mechanism of the corrosion inhibition of AZ31 and WE43 Mg alloys by aqueous molybdate in Hank’s solution.

  • Exploring music listening patterns: an online survey
    • Barbara Szyca
    • Bartosz Wejda
    • Marta Muchewicz
    • Bożena Kostek
    2024 Pełny tekst International Journal of Electronics and Telecommunications

    An online survey was carried out to explore how respondents listen to music recordings. It was anticipated that the listener’s preferences would be influenced by various factors, such as age, music genre, the contexts in which they listen, and their favored methods of music consumption. Consequently, the data were collected to analyze these relationships. The survey, structured as a web application, encompassed 23 questions, with seven specifically aimed at defining the respondents and the remainder contributing to the dataset for analysis. The results reveal a prevailing preference for listening to music via streaming platforms. Respondents predominantly engage in passive listening, where music becomes a background presence without commanding their focused attention. Moreover, the data also highlight a noteworthy correlation between preferred music genres and the age of the listeners.

  • Exploring Neural Networks for Musical Instrument Identification in Polyphonic Audio
    • Maciej Blaszke
    • Grazina Korvel
    • Bożena Kostek
    2024 IEEE INTELLIGENT SYSTEMS

    The purpose of this paper is to introduce neural network-based methods that surpass state-of-the-art (SOTA) models, either by training faster or having simpler architecture, while maintaining comparable effectiveness in musical instrument identification in polyphonic music. Several approaches are presented, including two authors’ proposals, i.e., spiking neural networks (SNN) and a modular deep learning model named FMCNN (Fully Modular Convolutional Neural Network). First, a convolutional neural network (CNN) and convolutional-recurrent neural network (CRNN), adapted from literature, are built to detect up to 13 different instruments in polyphonic music. Furthermore, FMCNN and SNN are explored. The results obtained demonstrate that both FMCNN and SNN outperform traditional CNN and CRNN in terms of accurate instrument identification. Moreover, the SNN architecture is much less complex compared to other model sizes. These findings highlight the efficacy of the methods proposed in musical instrument identification in polyphonic audio.

  • Exploring novel Cd(ii) complexes with 5-methyl-4-imidazolecarboxaldehyde: synthesis, structure, computational insights, and affinity to DNA through switchSense methodology
    • Mateusz Kowalik
    • Paulina Nowicka
    • Jakub Brzeski
    • Natalia Żukowska
    • Joanna Masternak
    • Katarzyna Kazimierczuk
    • Mariusz Makowski
    2024 DALTON TRANSACTIONS

    A series of four Cd(II) complexes with 5-methyl-4-imidazolecarboxaldehyde (L) with different inorganic anions within or outside the coordination sphere of general formula: [CdCl2 L2 ] (1), [CdBr2 L 2] (2), [CdI2L 2] (3), and [CdL4 ](PF6 )2 ·3H2 O (4) was synthesized through one-step and two-step reactions, respectively. All complexes were obtained as colorless crystals without the need for recrystallization and exhibited solubi- lity in aqueous solutions. Structural analysis revealed different coordination environments for each complex, with variations in bond lengths and angles. The crystal packing of the complexes was stabilized by hydrogen bonding and π–π stacking interactions. FT-IR analysis indicated coordination of the ligand to the metal ion, and UV-Vis studies confirmed the stability of the complexes in solution. Computational analysis has revealed the polar nature of the complexes and their favorable stability constants. Affinity studies with DNA using the switchSense technique demonstrated rapid association and dissociation pro- cesses for all complexes, with temperature-dependent binding constants. Thermodynamic analysis suggested spontaneous with positive entropy change and endothermic formation processes for the com- plexes. Overall, the study underscores the synthesis, examination, and interaction with DNA of Cd(II ) com- plexes, demonstrating their promise within medicinal chemistry.

  • Exploring Relationships Between Data in Enterprise Information Systems by Analysis of Log Contents
    • Łukasz Korzeniowski
    • Krzysztof Goczyła
    2024

    Enterprise systems are inherently complex and maintaining their full, up-to-date overview poses a serious challenge to the enterprise architects’ teams. This problem encourages the search for automated means of discovering knowledge about such systems. An important aspect of this knowledge is understanding the data that are processed by applications and their relationships. In our previous work, we used application logs of an enterprise system to derive knowledge about the interactions taking place between applications. In this paper, we further explore logs to discover correspondence between data processed by different applications. Our contribution is the following: we propose a method for discovering relationships between data using log analysis, we validate our method against a real-life system running at Nordea Bank, we provide detailed insights into a real-life dataset, we analyze the influence of log quality on the results provided by our method, and we provide recommendations for developers on logging practices that can support the log analysis.

  • Exploring the Antitumor Efficacy of N-Heterocyclic Nitrilotriacetate Oxidovanadium(IV) Salts on Prostate and Breast Cancer Cells
    • Katarzyna Chmur
    • Aleksandra Tesmar
    • Magdalena Zdrowowicz
    • Damian Rosiak
    • Jarosław Chojnacki
    • Dariusz Wyrzykowski
    2024 Pełny tekst MOLECULES

    The crystal structures of two newly synthesized nitrilotriacetate oxidovanadium(IV) salts, namely [QH][VO(nta)(H2O)](H2O)2 (I) and [(acr)H][VO(nta)(H2O)](H2O)2 (II), were determined. Additionally, the cytotoxic effects of four N-heterocyclic nitrilotriacetate oxidovanadium(IV) salts— 1,10-phenanthrolinium, [(phen)H][VO(nta)(H2O)](H2O)0.5 (III), 2,2′-bipyridinium [(bpy)H][VO(nta)(H2O)](H2O) (IV), and two newly synthesized compounds (I) and (II)—were evaluated against prostate cancer (PC3) and breast cancer (MCF-7) cells. All the compounds exhibited strong cytotoxic effects on cancer cells and normal cells (HaCaT human keratinocytes). The structure–activity relationship analysis revealed that the number and arrangement of conjugated aromatic rings in the counterion had an impact on the antitumor effect. The compound (III), the 1,10-phenanthrolinium analogue, exhibited the greatest activity, whereas the acridinium salt (II), with a different arrangement of three conjugated aromatic rings, showed the lowest toxicity. The increased concentrations of the compounds resulted in alterations to the cell cycle distribution with different effects in MCF-7 and PC3 cells. In MCF-7 cells, compounds I and II were observed to block the G2/M phase, while compounds III and IV were found to arrest the cell cycle in the G0/G1 phase. In PC3 cells, all compounds increased the rates of cells in the G0/G1 phase.

  • Exploring the Beam Squint Effects on Reflectarray Perfromance: A Comprehensive Analysis of the Specular and Scattered Reflection of the Unit Cell
    • Manzoor Elahi
    • Amir Altaf
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2024 Pełny tekst SENSORS

    In this article, the phenomena of beam deviation in reflectarray is discussed. The radiation pattern of the unit cell, which plays a vital role in shaping the beam of the reflectarray, is analyzed by considering undesired specular and scattered reflections. These unwanted reflections adversely affect the pattern of the single unit cell, thereby reducing the overall performance of the reflectarray. To conduct our investigations, three cases of reflectarray, i.e., (i) a center-fed with broadside beam (Case-I), (ii) a center-fed with the beam at 30∘ (Case-II), and (iii) off-center fed with the beam at 30∘ reciprocal to feed position with reference to the broadside direction (Case-III), are simulated. Different degrees of beam deviation are analyzed in each reflectarray by assessing the radiation pattern of a single element. The significance of specular reflections is further confirmed by half (left half and right half) aperture analysis of Case-II. This involves simulating the half-plane aperture illuminated by horn antenna, resulting in a distinct beam angle at the same frequency. Although the analysis specifically focuses on the three cases of the reflectarray, the proposed methodology is applicable to any type of reflectarray. The study presented in this work provides an important insight into the practical aspects of reflectarray operation, particularly in terms of quantifying undesirable effects that are normally overlooked in the design of this class of arrays. Moreover, this work holds significant potential for remote sensing satellite systems as beam deviation can adversely impact data collection accuracy and compromize observation precision, resulting in distorted images, reduced data quality, and overall hindrance to the system’s performance in capturing reliable information.

  • Exploring the Benefits, Challenges, and Opportunities of Collaborative Business Intelligence
    • Paweł Weichbroth
    • Jozef Zurada
    • Celina Olszak
    2024 Pełny tekst

    In traditional business intelligence (BI) settings, the collective decision-making process is often hindered by the absence of knowledge and expertise exchange among various stakeholders, as well as lack of information sharing. The study delves into the concept of Collaborative BI, which aims to overcome these limitations by promoting collaboration, business networking, knowledge sharing, and improved communication among stakeholders. Based on a systematic literature review, the study explores the notion of Collaborative BI, formulates its definition, and reports on its challenges, benefits, and limitations. It also provides an insightful overview of Collaborative BI landscape and multiple advantages it can deliver to modern business organizations. The study also acknowledges potential threats to the validity of its findings due to the limited scope of the literature review. Finally, the study highlights the need for further research to address the limitations and expand our understanding of the CBI field

  • Exploring the potential of green chemistry in reversed-phase liquid chromatography: A review of sustainable solvents
    • Oktawia Kalisz
    • Marek Tobiszewski
    • Alicja Nowaczyk
    • Szymon Bocian
    2024 TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    This article delves into the growing field of green analytical chemistry, focusing on sustainable solvents for reversed-phase liquid chromatography (RP LC). RP LC is a widely applied technique in the pharmaceutical, food, and environmental analysis industries, consuming vast quantities of toxic and non-renewable solvents that pose serious environmental and health risks. In response to the urgent need for greener alternatives, this review discusses organic solvents such as ethanol, innovative options such as Cyrene and dimethyl carbonate, and surfactants in micellar liquid chromatography (MLC). In addition, the potential of pure water, ionic liquids (ILs), and deep eutectic solvents (DESs) was evaluated. By analyzing the efficacy, environmental impact, and feasibility of green solvents, the review highlights their potential to replace conventional solvents, supporting safer and more sustainable analytical practices. This comprehensive and critical analysis of recent reports aims to guide future research and promote the use of green solvents in RP LC.

  • Exploring the role of brand experience in driving consumer emotions and engagement with sports brands in Australia
    • Bruno Schivinski
    • Mancuso Giulio
    • Magdalena Brzozowska-Woś
    2024 Pełny tekst Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

    Purpose: This paper aims to fill the theoretical gap in understanding and practical implementation by examining how sports brands in Australia use brand experience to link emotional response and brand engagement. Design/methodology/approach: The study fits into the positivist paradigm. The starting point is the stimulus-organism-response theory. A quantitative method, which is an online survey, was used to collect data. Responses from 610 respondents were collected, and after they were cleaned, data from 526 participants were analyzed. The conceptual model of the relationships between variables was verified using the regression method. Findings: The findings confirmed the hypotheses. Brands investing in comprehensive experiences effectively generate positive emotions among consumers, increasing consumer brand engagement. Research limitations/implications: The study sample was limited to the Australian population. Further limitations include the relatively small sample size and the participants' demographics skewed towards specific age ranges, which limit the potential for generalization to broader populations or industries. Future research could overcome these limitations by exploring different industries or cultural contexts and using more objective means of data collection. Practical implications: The article offers practical recommendations for creating emotionally compelling campaigns. More significant investment in experiential marketing can strengthen customer bonds and long-term relationships with sports brands. Social implications: Sports brands uniquely unite people and strongly influence communities, so sports organizations must consider the social consequences of their actions. Their actions can affect physical health and social integration, shaping values and building bonds between people. Sports organizations that consider the social aspects of their activities can build strong, positive relationships with fans, partners, and local communities. Originality/value: This article advances the understanding of experiential marketing by highlighting the importance of emotional responses in promoting strong associations between consumers and brands. The findings have implications for academics and practitioners working in advertising and brand communication more broadly in the context of the Australian sports industry.

  • Exploring the technological dimension of Autonomous sensory meridian response-induced physiological responses
    • Sahar Seifzadeh
    • Bożena Kostek
    2024 PeerJ

    Background In recent years, the scientific community has been captivated by the intriguing Autonomous sensory meridian response (ASMR), a unique phenomenon characterized by tingling sensations originating from the scalp and propagating down the spine. While anecdotal evidence suggests the therapeutic potential of ASMR, the field has witnessed a surge of scientific interest, particularly through the use of neuroimaging techniques including functional magnetic resonance imaging (fMRI) as well as electroencephalography (EEG) and physiological measures such as eye tracking (Pupil Diameter), heart rate (HR), heartbeat-evoked potential (HEP), blood pressure (BP), pulse rates (PR), finger photoplethysmography (PPG), and skin conductance (SC). This article is intended to provide a comprehensive overview of technology’s contributions to the scientific elucidation of ASMR mechanisms. Methodology A meticulous literature review was undertaken to identify studies that have examined ASMR using EEG and physiological measurements. The comprehensive search was conducted across databases such as PUBMED, SCOPUS, and IEEE, using a range of relevant keywords such as ‘ASMR’, ‘Autonomous sensory meridian response’, ‘EEG’, ‘fMRI’, ‘electroencephalography’, ‘physiological measures’, ‘heart rate’, ‘skin conductance’, and ‘eye tracking’. This rigorous process yielded a substantial number of 63 PUBMED and 166 SCOPUS-related articles, ensuring the inclusion of a wide range of high-quality research in this review. Results The review uncovered a body of research utilizing EEG and physiological measures to explore ASMR’s effects. EEG studies have revealed distinct patterns of brain activity associated with ASMR experiences, particularly in regions implicated in emotional processing and sensory integration. In physiological measurements, a decrease in HR and an increase in SC and pupil diameter indicate relaxation and increased attention during ASMR-triggered stimuli. Conclusions The findings of this review underscore the significance of EEG and physiological measures in unraveling the psychological and physiological effects of ASMR. ASMR experiences have been associated with unique neural signatures, while physiological measures provide valuable insights into the autonomic responses elicited by ASMR stimuli.

  • Exploring the trends in flux-cored arc welding: scientometric analysis approach
    • Aleksandra Świerczyńska
    • Balázs Varbai
    • Chandan Pandey
    • Dariusz Fydrych
    2024 Pełny tekst INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY

    Flux-cored arc welding (FCAW) is a universal group of welding methods in terms of the scope of application and automation possibilities, the share of which in various industries in many countries is still increasing. The paper presents the results of bibliographic analyses (scientometric analysis with the use of VOSviewer, Bibliometrix and CitNetExplorer tools) of a data set of 993 publications indexed in the Web of Science database on the subject of FCAW for all types of flux-cored wires. An objective and unbiased approach to analysis resulted in a relatively neutral assessment of the state of knowledge in the field of FCAW and allowed for the identification of research directions carried out in the world, the dynamics of their changes as well as research gaps and needs. The scientometric analysis approach provided a holistic picture of the development of FCAW over the last 58 years, pointing to the geographical areas where this process has been and is most intensively researched, the agencies funding this research, the most active research teams, as well as the journals that have most often published articles on this topic. The most current research directions in relation to FCAW include underwater welding, hardfacing and cladding purposes, health and safety issues, and more general topic: properties and weldability of ferrous alloys. However, among the most urgent research needs the following topics: fatigue analysis of welded joints, environmental degradation of flux-cored wires, properties and weldability of nickel alloys, development of hybrid and combined welding procedures can be listed.

  • Exposure to cooking emitted volatile organic compounds with recirculating and extracting ventilation solutions
    • Wojciech Wojnowski
    • Aileen Yang
    • Tomas Mikoviny
    • Armin Wisthaler
    • Kari Thunshelle
    2024 Pełny tekst BUILDING AND ENVIRONMENT

    Energy-efficient urban development leads to the compact design of apartments. Recirculating ventilation solutions are an attempt to minimize the space required for ventilation ducting, but more data on their performance are needed. Cooking is a major source of volatile organic compounds (VOCs) emissions. It is necessary to assess how well recirculating kitchen hoods perform in reducing the residents' exposure to cooking fumes compared to extracting hoods, and what airflow rates assure good removal efficiency. We have monitored the occupant exposure to several VOCs generated during the cooking of a model meal under different ventilation scenarios in a purpose-built test kitchen resembling the layout of a modern, open-space apartment. Time-resolved VOC emission profiles were measured using a proton transfer reaction time-of-flight mass spectrometer. The performance of activated carbon sorption-based filters for recirculating kitchen hoods in the removal of selected VOCs was also assessed. Alcohols, particularly ethanol, dominated emissions from cooking a typical Norwegian meal, but they also included acetaldehyde, acetone, carboxylic acids, and trimethylamine, among others. The use of recirculating kitchen hoods led to, on average, higher occupant exposure to VOCs compared to extracting kitchen hoods during and after cooking. This was in part due to the poor ethanol removal efficiency of the recirculating ventilation's air filters.

  • Extending loophole-free nonlocal correlations to arbitrarily large distances
    • Anubhav Chaturvedi
    • Giuseppe Viola
    • Marcin Pawłowski
    2024 Pełny tekst npj Quantum Information

    Quantum theory allows spatially separated observers to share nonlocal correlations, which enable them to accomplish classically inconceivable information processing and cryptographic feats. However, the distances over which nonlocal correlations can be realized remain severely limited due to their high fragility to noise and high threshold detection efficiencies. To enable loophole- free nonlocality across large distances, we introduce Bell experiments wherein the spatially separated parties randomly choose the location of their measurement devices. We demonstrate that when devices close to the source are perfect and witness extremal nonlocal correlations, such correlations can be extended to devices placed arbitrarily far from the source. To accommodate imperfections close to the source, we demonstrate an analytic trade-off: the higher the loophole-free nonlocality close to the source, the lower the threshold requirements away from the source. We utilize this trade-off and formulate numerical methods to estimate the critical requirements of individual measurement devices in such experiments.