2023 - Repozytorium publikacji - Politechnika Gdańska

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A review of methods of blood supply to organs of the gastrointestinal tract. State of art
- Zieliński Jacek
- Adam Bujnowski
- Norbert Szram
- Weronika Szczecińska
- Jakub Woźniak
- Sergii Girnyi
- Michalina Ciosek
- Magdalena Tulińska
- Jerzy Wtorek
2023 EJSO-EUR J SURG ONC
The correct assessment of blood supply is essential to eliminate possible postoperative complications. Re-anastomosis of the gastrointestinal tract after its resection must be preceded by the analysis of blood supply to the anastomosed fragments. It is important that the blood supply assessment procedure is reliable but also non-absorbing and, if possible, short. It should also be possible to repeat the procedure due to the need to change the anastomosed part. If the blood supply to the tissues is incorrectly estimated and, as a result, an inappropriate anastomosis, e.g. of the intestine, postoperative complications may occur, which in their mildest stage necessitate corrective surgery, and in their worst stage may lead to serious consequences, including death of the patient.
A review of phase change materials and heat enhancement methodologies
- Muhammad Saqib
- Rafał Andrzejczyk
2023 Pełny tekst Wiley Interdisciplinary Reviews-Energy and Environment
Phase change materials (PCMs) are an efficient alternative to store and release heat at a specific range of temperature. Here PCMs and heat enhancement methodologies for PCM storage are reviewed. A short overview of PCMs and their applications is presented in addition to the progress during the last 10 years. Heat enhancement techniques, that is, extended surfaces, multiple and composite PCMs, and encapsulation techniques, are presented along with a statistical overview of studies during 2016–2021. The importance of various fin and storage tank geometries (extended surfaces) is discussed in detail. Advancement in the latest heat enhancement techniques such as use of nano-enhanced PCMs is presented. Recommendations for future research are provided.
A selectively reduced degree basis for efficient mixed nonlinear isogeometric beam formulations with extensible directors
- Myung-Jin Choi
- Roger Sauer
- Sven Klinkel
2023 Pełny tekst COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
The effect of higher order continuity in the solution field by using NURBS basis function in isogeometric analysis (IGA) is investigated for an efficient mixed finite element formulation for elastostatic beams. It is based on the Hu–Washizu variational principle considering geometrical and material nonlinearities. Here we present a reduced degree of basis functions for the additional fields of the stress resultants and strains of the beam, which are allowed to be discontinuous across elements. This approach turns out to significantly improve the computational efficiency and the accuracy of the results. We consider a beam formulation with extensible directors, where cross-sectional strains are enriched to avoid Poisson locking by an enhanced assumed strain method. In numerical examples, we show the superior per degree-of-freedom accuracy of IGA over conventional finite element analysis, due to the higher order continuity in the displacement field. We further verify the efficient rotational coupling between beams, as well as the path-independence of the results.
A Series of Novel 3D Coordination Polymers Based on the Quinoline-2,4-dicarboxylate Building Block and Lanthanide(III) Ions—Temperature Dependence Investigations
- Dmytro Vlasyuk
- Renata Łyszczek
- Mazur Liliana
- Agnieszka Pladzyk
- Zbigniew Hnatejko
- Przemysław Woźny
2023 Pełny tekst MOLECULES
A series of novel 3D coordination polymers [Ln2(Qdca)3(H2O)x]yH2O (x = 3 or 4, y = 0–4) assembled from selected lanthanide ions (Ln(III) = Nd, Eu, Tb, and Er) and a non-explored quinoline- 2,4-dicarboxylate building block (Qdca2 = C11H5NO4 2) were prepared under hydrothermal conditions at temperatures of 100, 120, and 150 C. Generally, an increase in synthesis temperature resulted in structural transformations and the formation of more hydrated compounds. The metal complexes were characterized by elemental analysis, single-crystal and powder X-ray diffraction methods, thermal analysis (TG-DSC), ATR/FTIR, UV/Vis, and luminescence spectroscopy. The structural variety of three-dimensional coordination polymers can be ascribed to the temperature effect, which enforces the diversity of quinoline-2,4-dicarboxylate ligand denticity and conformation. The Qdca2 ligand only behaves as a bridging or bridging–chelating building block binding two to five metal centers with seven different coordination modes arising mainly from different carboxylate group coordination types. The presence of water molecules in the structures of complexes is crucial for their stability. The removal of both coordinated and non-coordinated water molecules leads to the disintegration and combustion of metal–organic frameworks to the appropriate lanthanide oxides. The luminescence features of complexes, quantum yield, and luminescent lifetimes were measured and analyzed. Only the Eu complexes show emission in the VIS region, whereas Nd and Er complexes emit in the NIR range. The luminescence properties of complexes were correlated with the crystal structures of the investigated complexes.
A significance of multi slip condition for inclined MHD nano-fluid flow with non linear thermal radiations, Dufuor and Sorrot, and chemically reactive bio-convection effect
- Bilal Ahmad
- Muhammad Ozair Ahmad
- Muhammad Farman
- Ali Akgül
- Muhammad Riaz
2023 Pełny tekst South African Journal of Chemical Engineering
The aim of this research is to discuss the significance of slip conditions for magnetized nanofluid flow with the impact of nonlinear thermal radiations, activation energy, inclined MHD, sorrot and dufour, and gyrotactic micro motile organisms over continuous stretching of a two-dimensional sheet. The governing equations emerge in the form of partial differential equations. Since the resultant governing differential equations are nonlinear, the partial differential equations are transformed into ordinary differential equations using a workable similarity transformation. By using the Bvp4c module of the MATLAB program, the simplified mathematical framework can be numerically solved. The computation of Coefficients of skin friction, Nusselt numbers, different patterns of velocity profiles, fluid temperature, and concentration profiles reveals the physical nature of this study. As compared to earlier investigations, it was found that the obtained results demonstrated high degrees of symmetry and precision. A decline observes in velocity for boosted values of MHD, inclination, and rotatory parameter. However thermal transportation increases by increasing brownien motion, thermophoresis, radiation and Sorrot effect. The study has significant application in heat control systems, food factories, thermal exchangers, biomechanics, biomedical engineering, and aero dynamical systems
A simplified approach to determine the expiration date of certified reference material based on the results of monitoring long-term stability
- Chintankumar Padariya
- Małgorzata Rutkowska
- Piotr Konieczka
2023 MICROCHEMICAL JOURNAL
All components of the quality assurance (QA) system for measurement results depend heavily on certified reference materials (CRMs). There is a need for a comprehensive discussion of the stability study using the CRM statistical method. Monitoring involves periodic sampling and analysis of the CRM at predetermined intervals to continuously monitor stability without compromising its integrity. The obtained stability data is then subjected to statistical analysis, considering factors such as trends, variability, and acceptable limits. In this study, we propose a simplified approach as a linear trend to determine the expiration date of CRM. A case study is conducted using the application of the mentioned statistical approaches according to ISO GUIDE 35:2017 with the inclusion of a linear trend for four MODAS CRMs based on the total mercury (THg) content, which all met the positive criteria for each test and CRM. The proposed approach may be helpful when the requirements stated in section B.4.2 (NOTE 3) are not met of the ISO GUIDE 35:2017. Although the shelf-life is an estimated value, it is, therefore, possible to apply simplifications in the course of its determination. The linear trend analysis would serve an ideal role while accessing the long-term stability study of the CRMs.
A simplified method to assess the impact of ship-to-ship collision on the risk of tanker ship hull girder breaking accounting for the effect of ageing
- Krzysztof Wołoszyk
- Jakub Montewka
- Floris Goerlandt
2023 Pełny tekst
One of the most critical structural failures is the exceedance of the ship hull girder’s ultimate strength, which may result in hull breaking, and subsequent severe consequences, including loss of life and property as well as environmental damage in case of an oil spill. A cause for such loss of structural continuity can be triggered by a collision with another vessel. In addition, the ageing mechanisms of the hull structure could increase this risk. However, the majority of models for damage risk dedicated to collision and grounding accidents do not sufficiently account for the ageing effect. Furthermore, current risk models usually only consider oil spills due to perforation of the ship side, neglecting the ensuing risks of hull girder breaking. Therefore, in the presented work, we propose a simplified method to assess the probability of exceedance of the hull girder’s ultimate strength of a tanker ship, accounting both for the impact of corrosion degradation and the loss of the part of the midship cross-section due to collision with another vessel. A case study of a VLCC tanker ship is analysed to demonstrate the proposed methodology. Further ensuing consequences related to a hull girder failure are briefly discussed. Finally, key conclusions are given, and future research directions are outlined.
A Simplified SVPWM Technique for Five-leg Inverter with Dual Three-phase Output
- Dmytro Kondratenko
- Arkadiusz Lewicki
2023 Pełny tekst
This article proposes a simplified space vector pulse-width modulation (SVPWM) technique five-leg inverter with dual three-phase output. An idea to fed the dual tree-phase machine by the multiphase voltage source inverters (VSIs) is not new. Dual- and multi-motor drive systems are widely used in the industry applications. The most popular fields are: electric vehicles (EVs) and traction systems. Moreover, the specific characteristic of the dual-drive systems allow to use them in the paper and textile production process. Mostly these solutions utilize carrier-based PWM (CBPWM) techniques for the output voltage generation, however the SVPWM techniques might be also used for this purpose. The main idea of this paper is to simplify the modulation process and obtain the similar algorithms complexity and execution times for the space-vector and carrier-based PWM techniques. The proposed SVPWM strategy allows to decrease the number of calculations at the initial stage of the algorithm. The output voltages for both loads/motors can be generated independently, with different frequencies and amplitudes. Simulation results were obtained using the PLECS software package. The experimental investigation with RL load were conducted as well. The carried tests proved the effectiveness of the proposed modulation strategy. All results are shown in this paper.
A Simplistic Downlink Channel Estimation Method for NB-IoT
- Jarosław Magiera
2023 Pełny tekst Applied Sciences-Basel
This paper presents a downlink channel estimation method intended for a Narrowband Internet of Things (NB-IoT) access link. Due to its low computational complexity, this method is well suited for energy-efficient IoT devices, still providing acceptable reception quality in terms of signal-to-noise (SNR) performance. This paper describes the physical layer of NB-IoT within the scope of channel estimation, and also reviews existing channel estimation methods for OFDM signals. The proposed method, based on linear interpolation of channel coefficients, is described as a three-step procedure. Next, indicators of channel quality assessment, which may be determined without prior knowledge about the transmitted signal, are defined. Two variants of channel estimation, differing in the frequency domain processing, are evaluated to assess the significance of frequency selectivity in an NB-IoT downlink. The chosen method is compared with another method implemented in MATLAB LTE ToolboxTM. An analysis of the computation time is conducted, subsequently demonstrating the definite advantage of the proposed method.
A Study of Mutual Coupling Suppression between Two Closely Spaced Planar Monopole Antenna Elements for 5G New Radio Massive MIMO System Applications
- Rao Aziz
- Sławomir Kozieł
- Leifur Leifsson
- Stanisław Szczepański
2023 Pełny tekst Electronics
5G NR (new radio) introduces the concept of massive MIMO (multiple-input-multiple-output) technology, in which a larger number of antenna arrays are installed on the transceiver. Due to the increased number of antenna elements allocated close to each other (approximately at half-wavelength distance), mutual coupling becomes a serious problem leading to performance degradation of the MIMO communication system. In this communication, two different config-urations of closely-spaced antenna array elements are studied. In order to reduce the mutual coupling, a combination of a metamaterial-based frequency selective surface (FSS), a metallic strip, and a slot element in the ground plane, is examined. It has been found that the proposed technique significantly suppresses mutual coupling from –12dB to –25dB. Both designs are fab-ricated and experimentally validated. The simulation results are in good agreement with the measurements. The proposed mutual coupling reduction technique may be suitable for massive MIMO systems in the fifth-generation (5G) new radio applications.
A study on microcrack monitoring in concrete: discrete element method simulations of acoustic emission for non-destructive diagnostics
- Magdalena Rucka
- Magdalena Knak
- Michał Nitka
2023 Pełny tekst ENGINEERING FRACTURE MECHANICS
The research is focused on the monitoring of fracture evolution in concrete beams under three-point bending using the acoustic emission technique and the discrete element method. The main objective of the study was to numerically and experimentally investigate the mechanism behind the generation of elastic waves during acoustic emission events and their interaction with micro- and macro-cracking in concrete beams under monotonic quasi-static loading. This was achieved through the development of a DEM model and numerical modelling of AE effects. An improved 4-phase DEM model of concrete including real mesostructured specimens and the ability to simulate aggregate breakage was introduced. The propagation of elastic waves, recorded in both laboratory experiments and numerical calculations, was given particular attention. The results showed the high suitability of the developed DEM model for monitoring crack initiation, development and propagation, as well as for supporting the interpretation of diagnostic results obtained by acoustic emission techniques.
A survey of automatic speech recognition deep models performance for Polish medical terms
- Marta Zielonka
- Wiktor Krasiński
- Jakub Nowak
- Przemysław Rośleń
- Jan Stopiński
- Mateusz Żak
- Franciszek Górski
- Andrzej Czyżewski
2023
Among the numerous applications of speech-to-text technology is the support of documentation created by medical personnel. There are many available speech recognition systems for doctors. Their effectiveness in languages such as Polish should be verified. In connection with our project in this field, we decided to check how well the popular speech recognition systems work, employing models trained for the general Polish language. For this purpose, we selected 100 words from the International Classification of Diseases dictionary, the Polish-language version of the International Statistical Classification of Diseases and Health Problems. The words were read into a microphone by five women and five men and also generated with a speech synthesizer using a male and a female voice. This resulted in 1,200 recordings tested with the following systems: Whisper, Google speech-to-text, and Microsoft Azure speech-to-text. The achieved word recognition performance is reflected by the calculated metrics: WER, WIL, Levenshtein distance, Jaccard distance, MER, and CER. Results show that the highest efficiency for most cases was obtained by Azure speech-to-text. However, none of the tested models is ready for voice-filling medical records, describing cases, or prescribing treatment, because the number of errors made when converting speech to text is too high.
A Web-GIS tool for diagnosing spatial orientation of young adults: design and evaluation of Geo-Survey
- Marcin Kulawiak
- Dominik Krajnik
- Marta Czaplicka
- Agnieszka Dawidowicz
2023 Pełny tekst Scientific Reports
Spatial orientation is the effectiveness with which one is able to assess the mutual location of objects relative to a point of reference or a system of coordinates. Traditionally, this ability has been evaluated through field navigation tests, which do not take into account the prevailing influence of free online maps and virtual walks on a person’s interpretation of space. In this context, this study presents a Web-GIS tool designed and developed to examine spatial orientation skills in the context of the used map type. The tool, named Geo-Survey, enables combination of survey questions with customized maps, providing users with a set of possible answer types. Moreover, using the unique concept of predefined answers, the tool attempts to automate the process of analysing research results. The tools’ performance is evaluated via assessing the spatial orientation skills of a group of young adults.
A Wideband Rotary-Joint-Free H-Plane Horn Antenna With 360° Steerable Radiation Pattern Using Gap Waveguide Technology
- Ali Karami Horestani
- Michał Mrozowski
2023 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
Considering the limitations of electronically steerable antennas such as limited steering span, gain degradation for large steering angles, complexity, and cost, this article is focused on the design of a simple mechanically steerable H-plane horn antenna. It is shown that since there is no need for an electrical connection between the top and bottom sections of a gap waveguide (GWG), if a sectoral horn is properly designed and realized using this technology, the pattern of the antenna can be easily steered without a rotary joint. To demonstrate this concept, a rotary-joint-free H-plane horn antenna is designed, and its performance is predicted using EM simulations. The antenna offers a wide operating band covering almost the entire Ku-band and provides a full 360◦ continuous steering span. Additionally, the proposed antenna benefits from a constant gain over the full range of steering angles. This is in contrast to phased array antennas whose gain degrades when the main beam is steered away from the broadside. The proposed concept and computed characteristics are verified by the good agreement between the simulated and measured characteristics of the fabricated prototype
Ab initio chemical kinetics of Isopropyl acetate oxidation with OH radicals
- Mohamed A. Abdel-Rahman
- Mohamed F. Shibl
- Abolfazl Shiroudi
- Mohamed A. M. Mahmoud
2023 Pełny tekst Green Chemistry Letters and Reviews
Global reactivity descriptors of isopropyl acetate (IPA) and thermo-kinetic aspects of its oxidation via OH radicals have been studied. Transition state theory (TST) was utilized to estimate the bimolecular rate constants. Ten oxidation pathways have been investigated, and all of them are exothermic. The potential energy diagram has been sketched using different pre- and post-reactive complexes for all reaction pathways. Rate coefficient calculations were obtained directly by connecting the separated reactants with different transition states. The results indicate that the reaction of IPA with OH radicals occurs in the ground state rather than the excited state, and the rate constants obtained directly and from the effective approach are the same, which confirmed the accuracy of the estimated pre-reactive complexes and the reaction mechanism. Rate constants and branching ratios show that hydrogen atom abstraction from the iso C − H (C2 atom) bond is the most kinetically preferable route up to 1000 K, while at higher temperatures, H-atom abstraction from the out-of-plane CH3 group (C3 atom) became the most dominant route with high competition with that of the in-plane CH3 group (C4 atom).
About definition of modes and magnetosonic heating in a plasma’s flow: Especial cases of perpendicular and nearly perpendicular wave vector and magnetic field
- Anna Perelomova
2023 Pełny tekst CONTRIBUTIONS TO PLASMA PHYSICS
Dynamics of hydrodynamic perturbations in a plasma depend strongly on an angle between the wave vector and equilibrium straight magnetic field. The case of perpendicular propagation is especial. There are only two (fast) magnetosonic modes since two (slow) ones degenerate into the stationary one with zero speed of propagation. This demands individual definition of wave modes by the links of hydrodynamic relations. These links are not limiting case of the relations in the case of non-zero angle. The nonlinear excitation of the entropy mode in the field of intense magnetosonic perturbations is also unusual. Bulk and shear viscosity and thermal conduction are considered as the damping mechanisms in a weakly nonlinear flow. The leading-order dynamic equation is derived which governs perturbation of density in the entropy mode. The links of magnetosonic perturbations and magnetosonic heating may be indicators of plasma-, geometry of a flow, damping coefficients and type of wave motion. The “almost resonant” character of magnetosonic heating excited by the slow magnetosonic wave in the course of nearly perpendicular wave propagation, is discussed.
Accelerated Parameter Tuning of Antenna Structures by Means of Response Features and Principal Directions
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
2023 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
Popularity of numerical optimization has been steadily on the rise in the design of modern antenna systems. Resorting to mathematically rigorous parameter tuning methods is a matter of practical necessity as interactive techniques (e.g., parameter sweeping) are no longer adequate when handling several performance figures over multi-dimensional parameter spaces. The most common design scenarios involve local tuning since decent initial designs are often rendered at the early phases of the design process. Notwithstanding, antenna optimization is usually executed using full-wave electromagnetic (EM) simulation tools, inevitably requiring considerable amount of computational resources. This paper introduces a novel technique for expedited gradient-based antenna optimization with numerical derivatives. The two major acceleration mechanisms, both of which exploit the problem-specific knowledge carried by the antenna characteristics, include the response feature methodology and sparse sensitivity updates restricted to selected principal vectors. The former permits flattening the landscape of the objective function, whereas the latter effectively reduces the problem dimensionality to dimensions that have the most significant effect on antenna characteristics, which are established using an automated decision-making procedure. Our methodology is applied to optimize three antenna structures. Comparisons with several benchmark procedures indicate the relevance of the adopted mechanisms and considerable computational savings that can be achieved. The average savings amount to 50 percent over conventional trust-region gradient search, and slightly lower, yet still significant, over accelerated versions thereof.
Acceleration of Electromagnetic Simulations on Reconfigurable FPGA Card
- Tomasz Topa
- Artur Noga
- Tomasz Stefański
2023
In this contribution, the hardware acceleration of electromagnetic simulations on the reconfigurable field-programmable-gate-array (FPGA) card is presented. In the developed implementation of scientific computations, the matrix-assembly phase of the method of moments (MoM) is accelerated on the Xilinx Alveo U200 card. The computational method involves discretization of the frequency-domain mixed potential integral equation using the Rao-Wilton-Glisson basis functions and their extension to wire-to-surface junctions. Hardware resources in our FPGA card allow for synthesizing nine independent processing paths. The implementation is evaluated in a numerical test, which involves a simulation of radiation from a monopole antenna mounted on the roof of Dodge Shelby Charger car. Results show that the developed acceleration is 9.49× faster than a traditional (i.e., serial) central processing unit (CPU) MoM implementation, and about 1.66× faster than a parallel six-core CPU MoM implementation. However, in the considered numerical benchmark, the execution of the same computations on the hybrid CPU/FPGA platform reduces the power consumption 2.1× in comparison with the multicore implementation, hence, it allows for the reduction of environmental effects of scientific computing.
Accounting for the distributions of input quantities in the procedure for the measurement uncertainty evaluation when calibrating the goniometer
- Igor Zakharov
- Iryna Zadorozhna
- Dariusz Świsulski
- Dimitar Diakov
2023 Pełny tekst Ukrainian Metrological Journal
The discords concerning the measurement uncertainty evaluation in the Guide to the Expressing of Uncertainty in Measurement (GUM) and its Supplement 1 are considered. To overcome these discords, the authors of the paper propose to use the kurtosis method and the law of the propagation of the expanded uncertainty. Using the example of the goniometer calibration, the features of accounting for the distribution laws of input quantities in the procedure for the measurement uncertainty evaluation are shown. A model for direct measurements of the value of a reference measure of the angle using a goniometer is written, the procedures for the measurement uncertainty evaluation are described, and uncertainty budgets for each of the methods are given. An example of the measurement uncertainty evaluation when calibrating a digital goniometer using a 24-sided reference prism is described. An estimate of the expanded measurement uncertainty for this example was made based on the web-based software application NIST Uncertainty Machine, which showed a good agreement with the estimates obtained by the considered methods. The technology of applying this software application for the confidence level of 0,9545, which the software lacks, is shown. The estimates of the measurement uncertainty obtained by the proposed methods, Monte Carlo method and methodology of the Guide to the Expressing of Uncertainty in Measurement are compared.
Accurate electrothermal modelling of high frequency DC-DC converters with discrete IGBTs in PLECS software
- Pawel Gorecki
- Daniel Wojciechowski
2023 Pełny tekst IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
In the paper, a novel, improved method of the IGBT junction temperature computations in the PLECS simulation software is presented. The developed method aims at accuracy of the junction temperature computations in PLECS by utilising a more sophisticated model of transistor losses, and by taking into account variability of transistor thermal resistance as a function of its temperature. A detailed description of the proposed method, as well as the parameter estimation procedure is given. The method is verified experimentally for the case of a DC-DC boost converter. Any discrepancies between simulations and measurements are discussed in detail. The proposed method is well suited for accurate electrothermal circuit-level simulations of power electronics converters.