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Repozytorium publikacji
Politechniki Gdańskiej

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  • Affronter la distance et la séparation : l'utilisation des médias sociaux par les migrants dans leurs relations interpersonnelles
    • David Duenas Cid
    • Pilar Rodriguez
    2022

    L'augmentation progressive de la mobilité, de l'interconnectivité et de l'instabilité, la transformation du travail et de l'emploi et celle de la communication (Castells, 2010) ont contribué à l’émergence d’une déracinés et séparés de leur foyer évoluent vers de nouvelles perspectives les migrants comme des sujets mobiles et interconnectés qui, grâce aux TIC, peuvent entretenir des relations et des connexions à distance les liant à des réalités différentes de celles qu'ils vivent, en même temps : les migrants connectés (Diminescu, 2008). La déstabilisation et la dérèglementation qui se produisent dans les institutions mondiales nécessitent d'éviter l’analyse des mouvements de population en se basant uniquement sur les dimensions de l'émigration-immigration (de – vers). Autrement dit, la notion actuelle de migration est beaucoup et circulatoire (Castles, de Haas, & Miller, 2003).

  • Ag modified ZnO microsphere synthesis for efficient sonophotocatalytic degradation of organic pollutants and CO2 conversion
    • Muhammad Farooq Khan
    • Sayed Ul Hasnain Bakhtiar
    • Amir Zada
    • Fazal Raziq
    • Hassan Anwar Saleemi
    • Muhammad Khan
    • Pir Muhammad Ismail
    • Arnold C. Alguno
    • Rey Y. Capangpangan
    • Asad Ali
    • Salman Hayat
    • Sharafat Ali
    • Ahmed Ismail
    • Muhammad Zahid
    2022 Environmental Nanotechnology, Monitoring and Management

    The synthesis and design of non-precious and efficient sonophotocatalyts by an environment friendly technique are requisites for solar energy conversion and environmental remediation. This work reports the preparation of Ag/ZnO microspheres with different Ag contents through deposition–precipitation method for pollutant degradation and CO2 conversion. Detail structural investigation reveals that ZnO microspheres and Ag-ZnO microspheres depicting spherical morphologies with smooth and rough surface respectively. The sonophotoactivties measured at 40 kHz frequency demonstrated that 3Ag/ZnO microsphere exhibited respectively 55 and 28-times improved sonophotoactivities for acid red 17 (AR-17) degradation and CO2 conversion compared with virgin ZnO microsphere. The obtained sonophoto-efficiencies for AR-17 degradation and CO2 conversion were found to be much higher compared to photo-efficiencies under visible-light due to the spatial synergistic effect of sono/photo waves. These unprecedented sonophotoactivities are credited to ultrasonic waves, rapid charge separation and promoted O2 activation. The factors such as the catalyst dosage, dye concentration, time, and temperature influencing the sono-efficiency of dye were also investigated. This continuous advancement has shown that ZnO microsphere-based nanocomposites are critical in the environmental remediation and solar energy generation.

  • Age Prediction from Low Resolution, Dual-Energy X-ray Images Using Convolutional Neural Networks
    • Kamil Jańczyk
    • Jacek Rumiński
    • Tomasz Neumann
    • Natalia Kowalczyk
    • Wiśniewski Piotr
    2022 Pełny tekst Applied Sciences-Basel

    Age prediction from X-rays is an interesting research topic important for clinical applications such as biological maturity assessment. It is also useful in many other practical applications, including sports or forensic investigations for age verification purposes. Research on these issues is usually carried out using high-resolution X-ray scans of parts of the body, such as images of the hands or images of the chest. In this study, we used low-resolution, dual-energy, full-body X-ray absorptiometry images to train deep learning models to predict age. In particular, we proposed a preprocessing framework and adapted many partially pretrained convolutional neural network (CNN) models to predict the age of children and young adults. We used a new dataset of 910 multispectral images that were weakly annotated by specialists. The experimental results showed that the proposed preprocessing techniques and the adapted approach to the CNN model achieved a discrepancy between chronological age and predicted age of around 15.56 months for low-resolution whole-body X-rays. Furthermore, we found that the main factor that influenced age prediction scores was spatial features, not multispectral features.

  • AGREEprep – Analytical greenness metric for sample preparation
    • Wojciech Wojnowski
    • Marek Tobiszewski
    • Francisco Pena-Pereira
    • Elefteria Psillakis
    2022 Pełny tekst TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    This work proposes for the first time, a metric tool that gives prominence to sample preparation. The developed metric (termed AGREEprep) was based on 10 categories of impact that were recalculated to 0 e1 scale sub-scores, and then used to calculate the final assessment score. The criteria of assessment evaluated, among others, the choice and use of solvents, materials and reagents, waste generation, energy consumption, sample size, and throughput. Assessment was also based on the possibility to differentiate between criteria importance by assigning them weights. The assessment procedure was performed using an open access, intuitive software that produced an easy-to-read pictogram with information on the total performance and structure of threats. A compiled version of the open access software can be obtained from mostwiedzy.pl/AGREEprep. The applicability of AGREEprep was successfully demonstrated using six different methods as case studies.

  • Airborne wear particle emission from train brake friction materials with different contents of steel and copper fibres
    • Yurii Tsybrii
    • Izabela Zglobicka
    • Michal Kuciej
    • Oleksii Nosko
    • Karol Golak
    2022 Pełny tekst WEAR

    This study investigated the influence of the amount of steel and copper fibres in a train brake friction material on the tribological performance, emission intensity and characteristics of airborne wear particles. The particles were generated on a pin-on-disc tribometer under controlled friction and environmental conditions. It was found that the steel fibre results in a more intensive emission of 0.3–10 μm particles compared to the copper fibre. The abrasive wear of the steel disc sample is a predominating source of iron in 1–10 μm particles. The content of iron in these particles is proportional to the relative wear of the disc sample, whilst the content of copper increases with that in the friction material.

  • AITP - AI Thermal Pedestrians Dataset
    • Aleksandra Górska
    • Patrycja Guzal
    • Aleksandra Wędołowska
    • Martyna Włoszczyńska
    • Jacek Rumiński
    2022

    Efficient pedestrian detection is a very important task in ensuring safety within road conditions, especially after sunset. One way to achieve this goal is to use thermal imaging in conjunction with deep learning methods and an annotated dataset for models training. In this work, such a dataset has been created by capturing thermal images of pedestrians in different weather and traffic conditions. All images were manually annotated with bounding boxes. As a result, the created dataset consists of 9178 annotated, thermal images that can be used in many applications including nighttime pedestrian detection.

  • Akademicy Współczesności. Mistrz - Uczeń"
    • Dominika Krechowicz
    2022

    "Akademicy Współczesności, Mistrz - Uczeń" . Wystawa oraz aukcja dzieł sztuki współczesnej zorganizowana przez Dom Aukcyjny Polswissart w Warszawie. Wystawie towarzyszył katalog.

  • Aktualizacja modelu teoretycznego Mostu Rędzińskiego na podstawie pomiarów konstrukcji, po 10 latach eksploatacji
    • Krzysztof Żółtowski
    • Mikołaj Binczyk
    • Przemysław Kalitowski
    2022 Przegląd Budowlany

    W roku 2020 zrealizowano prace badawcze, które miały na celu ocenę stanu konstrukcji Mostu Rędzińskiego we Wrocławiu po 10 latach eksploatacji. W ramach badań eksperckich wykonano pomiary sił w wantach mostu metodą wibracyjną, dokonano pomiarów geodezyjnych przęseł i pylonu oraz zbudowano model numeryczny. Model posłużył do oceny aktualnego stanu wytężenia elementów konstrukcji. Konieczne było przeprowadzenie aktualizacji pierwotnego modelu teoretycznego z uwagi na szereg istotnych zmian, które z upływem czasu zachodzą w konstrukcji, a które trudno precyzyjnie oszacować w trakcie projektowania. Zmiany te są efektem pełzania betonu, relaksacji stali i osiadania fundamentów. W artykule przedstawiono proces aktualizacji modelu teoretycznego mostu podwieszonego na podstawie wyników pomiarów. Uwzględniono w niej wpływ technologii budowy, pierwotny naciąg want, efekty reologiczne oraz osiadania podpór. Ostatecznie uzyskano model, w którym siły w wantach oraz trwałe deformacje przęseł i pylonu są zgodne z wartościami pomierzonymi. Potwierdzono, że w modelowaniu konstrukcji podwieszonej bardzo istotne jest precyzyjne określenie ciężaru własnego przęseł oraz sił naciągu w wantach. Niewielkie błędy w ich przyjęciu mogą skutkować dużymi błędami w wyznaczonej geometrii obiektu i siłach wewnętrznych.

  • Akumulacja metali ciężkich w wybranych gatunkach ryb bałtyckich
    • Anfisa Ronda
    • Bartłomiej Cieślik
    2022

    Jednym z naturalnych składników basenów wodnych są metale ciężkie, jednak działanie czynników antropogenicznych powoduje, iż stężenie tych substancji chemicznych niekiedy wzrasta do poziomów zagrażających bezpośrednio wodnej florze i faunie oraz pośrednio zdrowiu człowieka. Celem badań była ocena skażenia mięsa bałtyckich ryb metalami ciężkimi. W ramach przeprowadzonych badań analizie zostały poddane następujące gatunki ryb: makrela atlantycka, ryby z rodziny flądrowatych, sandacz pospolity, śledź bałtycki, okoń pospolity i łosoś europejski. Ryby były pozyskiwane od lokalnych sprzedawców portów w okolicach Trójmiasta. Do analizy zawartości metali została wybrana część grzbietowa mięsa ryb. Stężenie chromu, cynku, glinu, kadmu, kobaltu, manganu, miedzi, niklu w badanych tkankach oznaczono z wykorzystaniem techniki atomowej spektrometrii emisyjnej z atomizacją w plazmie mikrofalowej (MP-AES). Do oznaczenia zawartości rtęci wykorzystano technikę atomowej spektrometrii absorpcyjnej z atomizacją techniką zimnych par (CV-AAS). Na podstawie analizy wyników badań wykazano, że stężenie rtęci w tkankach badanych gatunków ryb mieściło się na ogół w zakresie 0,08-0,13 mg/kg świeżej masy. W oparciu o dane EFSA, dotyczące maksymalnej dopuszczalnej ilości spożycia wspomnianego metalu, stwierdzono, iż takie stężenie rtęci w pewnych warunkach może być szkodliwe dla zdrowia konsumentów ryb. Zawartość innych analizowanych pierwiastków była na dopuszczalnym, nie zagrażającym zdrowiu poziomie.

  • Algoritmically improved microwave radar monitors breathing more acurrate than sensorized belt
    • Andrzej Czyżewski
    • Bożena Kostek
    • Adam Kurowski
    • Krzysztof Narkiewicz
    • Beata Graff
    • Piotr Odya
    • Tomasz Śmiałkowski
    • Andrzej Sroczyński
    2022 Pełny tekst Scientific Reports

    This paper describes a novel way to measure, process, analyze, and compare respiratory signals acquired by two types of devices: a wearable sensorized belt and a microwave radar-based sensor. Both devices provide breathing rate readouts. First, the background research is presented. Then, the underlying principles and working parameters of the microwave radar-based sensor, a contactless device for monitoring breathing, are described. The breathing rate measurement protocol is then presented, and the proposed algorithm for octave error elimination is introduced. Details are provided about the data processing phase; specifically, the management of signals acquired from two devices with different working principles and how they are resampled with a common processing sample rate. This is followed by an analysis of respiratory signals experimentally acquired by the belt and microwave radar-based sensors. The analysis outcomes were checked using Levene’s test, the Kruskal–Wallis test, and Dunn’s post hoc test. The findings show that the proposed assessment method is statistically stable. The source of variability lies in the person-triggered breathing patterns rather than the working principles of the devices used. Finally, conclusions are derived, and future work is outlined.

  • Algorytm detekcji wąskopasmowych interferencji międzysystemowych ukrytych w paśmie pracy systemu LTE
    • Robert Burczyk
    • Jarosław Sadowski
    2022 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    W artykule zaprezentowano algorytm detekcji wąskopasmowych interferencji międzysystemowych w sygnale w ł ączu w dół sieci LTE. Zaproponowany algorytm detekcji interferencji bazuje na analizie zmienności faz konstelacji symboli OFDM w czasie. Artykuł zawiera także porównanie efektywności detekcji interferencji z metodą znaną z literatury.

  • Algorytm mrówkowy do zarządzania zasobami sprzętowymi chmury obliczeniowej w przypadku różnych kategorii usług
    • Henryk Krawczyk
    • Piotr Orzechowski
    2022

    Zarządzanie chmurą obliczeniową odbywa się na dwóch poziomach: zarządzanie żądaniami klientów chmury oraz zarządzanie jej infrastrukturą, na której te usługi są realizowane. Analizując standardy dotyczące zarządzania usługami, w niniejszym rozdziale skoncentrowano się na drugim poziomie zarządzania, którego głównym celem jest efektywne wykonanie wskazanej usługi (lub usług) na dostępnych zasobach sprzętowych, tak by spełnione zostały przyjęte kryteria optymalizacyjne. Dotyczy to przede wszystkim algorytmów przydziału (alokacji) niezbędnych zasobów dla każdej z usług oczekujących na wykonanie, przy uwzględnieniu wymagań wynikających z zawartych umów pomiędzy użytkownikiem a dostawcą takich usług (SLA). Zaproponowano algorytm mrówkowy, który jest akceptowalny dla różnych kategorii zgłaszanych przez użytkowników żądań. Jego działanie zilustrowano na trzech konkretnych przykładach wykonywanych aplikacji. Dalsze eksperymentalne badania jakości proponowanego algorytmu są przewidywane po jego implementacji w systemie zarządzania lokalnej chmury TASKcloud.

  • AMO model for neuro-inclusive remote workplace
    • Joanna Szulc
    2022 Pełny tekst Personnel Review

    Purpose The aim of this article is to extend current debates on organizational equality, diversity and inclusion to a consideration of neurodivergence in the remote workplace context. Design/methodology/approach Drawing on the ability, motivation, and opportunity (AMO) model and an emerging strength-based approach to neurodiversity, this conceptual paper integrates research on neurodiversity at work and remote working to provide a novel AMO model for a neuro-inclusive remote workplace. Findings Through a theoretically informed discussion of barriers to effective remote work from the perspective of neurominorities, the AMO model for the neuro-inclusive remote workplace is offered to assist organizations in creating an inclusive remote work environment where both neurominorities and neurotypicals can equally contribute to organizational success. Specific examples of how certain barriers to effective remote work can be mitigated are outlined and explained. Practical implications The conceptual model presented in this paper can assist HR practitioners in developing a comprehensive approach to skill, motivation, and opportunity-enhancing practices that are tailored to the unique needs of neurominorities in a specific context of remote work to generate mutual gains. Originality/value The model of interactions between individual and system factors offered enables a better theoretical understanding of the conditions under which high performance of neurodivergent individuals could be achieved with an associated positive impact on their well-being. The paper contributes to recent calls for more equitable and empathetic approaches to investing in employees with different cognitive profiles and does so in the underexplored context of remote work.

  • An Adaptive Network Model Simulating the Effects of Different Culture Types and Leader Qualities on Mistake Handling and Organisational Learning
    • Natalie Samhran
    • Jan Treur
    • Wioleta Kucharska
    • Anna Monika Wiewiora
    2022

    This paper investigates computationally the following research hypotheses: (1) Higher flexibility and discretion in organizational culture results in better mistake management and thus better organizational learning, (2) Effective organizational learning requires a transformational leader to have both high social and formal status and consistency, and (3) Company culture and leader's behavior must align for the best learning effects. Computational simulations of the introduced adaptive network were analyzed in different contexts varying in organization culture and leader characteristics. Statistical analysis results proved to be significant and supported the research hypotheses. Ultimately, this paper provides insight into how organizations that foster a mistake-tolerant attitude in alignment with the leader, can result in significantly better organizational learning on a team and individual level.

  • An analysis of observability and detectability for different sets of measured outputs - CSTR case study
    • Mateusz Czyżniewski
    • Rafał Łangowski
    2022

    A problem of proving the observability/detectability at a given measured output for non-linear biochemical systems has been addressed in this paper. A theory of indistinguishable state trajectories has been used to prove the properties of the observability or detectability of this system. It is related to taking system dynamics into consideration depending on initial conditions and the impact of inputs taking into account a given measured output. An analysis of the observability/ detectability has been performed for five cases where the various sets of measured outputs have been considered. The research results obtained are crucial for system state estimation that involves the synthesis of state observer. The proposed method may be successfully applied to the complex biochemical non-linear systems modelled as a continuous stirred tank reactor. Finally, the results obtained demonstrate the high effectiveness of the devised approach.

  • An Analysis of Sustainability Reporting Practices of the Global Airline Industry
    • Eljas Johansson
    2022 Pełny tekst

    Sustainability reporting (SR) has become a standard practice for many organisations worldwide. The purpose of this paper is to explore and develop our understanding of the global airline industry’s SR practices. Content analysis was employed to map which reporting frameworks the global commercial airline industry has recently used to report their non-financial impacts. Additionally, comparisons were made in the application of SR between geographical regions. The results indicate that two-thirds of the global airline companies had not published sustainability reports online (reporting period 2019). The Global Reporting Initiative (GRI) was the most widely used reporting instrument from the five major non-financial reporting organisations’ frameworks. Also, over two-thirds of the reports had used the Sustainable Development Goals (SDGs) as a reference framework or referenced SDGs in other ways. This paper provides one of the broadest overviews of global airline SR practices. It is expected that the results will be of interest to practitioners and scholars in aviation SR.

  • An analytical four-layer horizontal electric current dipole model for analysing underwater electric potential in shallow seawater
    • Mirosław Wołoszyn
    • Krystian Buszman
    • Tomasz Rutkowski
    • Jarosław Tarnawski
    • Javier Francisco Rodrigo Saura
    2022 Pełny tekst Scientific Reports

    The paper presents a new analytical four‑layer (air–water–bottom–non‑conductive layer) horizontal electric dipole model which allows an accurate approximation of ship’s Underwater Electric Potential (UEP) from a sufficient depth in shallow coastal marine waters. The numerical methods, usually Finite Element Method (FEM) or Boundary Elements Method (BEM), are typically used to estimate the electric field and the distribution of static electric components of UEP around the ship. These methods enable analyses with high accuracy but, compared to other point‑electrode methods and the proposed analytical model, they are relatively complex and need high computational time. The developed analytical model proposed in this paper allows real‑time calculations without significant loss of accuracy of the UEP estimations. In the model, the problem of boundary values at the borders of individual layers is solved using the reflection/image method and applying the idea of continuity of electric potential at a given boundary between two adjacent layers. Its accuracy is verified based on the synthetic data provided by specialised software packages making use of FEM and BEM numerical methods. A dimensionless quantitative analysis of the relationships between basic parameters of the proposed four‑layer analytical model and their impact on the accuracy of representation of individual electric field strength components is also delivered. The relationships between water and bottom conductivity and between water depth and bottom thickness are investigated and described. The obtained results show that the developed model allows detailed and reliable analysis of the electric field, especially in shallow coastal waters.

  • An automatic selection of optimal recurrent neural network architecture for processes dynamics modelling purposes
    • Krzysztof Laddach
    • Rafał Łangowski
    • Tomasz Rutkowski
    • Bartosz Puchalski
    2022 Pełny tekst APPLIED SOFT COMPUTING

    A problem related to the development of algorithms designed to find the structure of artificial neural network used for behavioural (black-box) modelling of selected dynamic processes has been addressed in this paper. The research has included four original proposals of algorithms dedicated to neural network architecture search. Algorithms have been based on well-known optimisation techniques such as evolutionary algorithms and gradient descent methods. In the presented research an artificial neural network of recurrent type has been used, whose architecture has been selected in an optimised way based on the above-mentioned algorithms. The optimality has been understood as achieving a trade-off between the size of the neural network and its accuracy in capturing the response of the mathematical model under which it has been learnt. During the optimisation, original specialised evolutionary operators have been proposed. The research involved an extended validation study based on data generated from a mathematical model of the fast processes occurring in a pressurised water nuclear reactor.

  • An Empirical Study on the Impact of Gender on Mobile Applications Usability
    • Paweł Weichbroth
    2022 Pełny tekst IEEE Access

    In the area of broadband wireless Internet, mobile applications have already replaced their desktop equivalents and are recognized as valuable tools for any size of businesses and for private use. With the emergence of millions of apps, the quality of their interaction with the user remains an open question for software vendors. While female and male requirements and preferences are not always similar, to the best of our knowledge, few studies have examined the impact of gender on mobile applications usability. Therefore, the goal of this study is to assess their usability from the perspective of female and male users, and to evaluate the differences between them. In our study, based on an experimental setup with a group of 40 users (16 females and 24 males), with regard to three usability attributes, namely efficiency, effectiveness and satisfaction, both qualitative and quantitative data were collected, respectively via pre- and post-testing questionnaires and during application testing sessions, combined with the think aloud protocol. To analyze the collected data, descriptive statistics were extracted from the video data and used to calculate the inferential statistics. With a significance level (alpha) of 5%, our findings show that between the groups of females and males, there were no statistically significant differences in the performance accuracy, average completion time, and perceived satisfaction, since all p values are greater than the assumed alpha. Hence, one can conclude that no effect of gender was observed with regard to the usability of the Gmail application. Overall, the empirical results contribute to the ongoing research on mobile application usability by providing evidence-based insights that we believe may be valuable for both theory and practice.

  • An Extended Control of the Input Angle for Matrix Converters Connected with the Non-Unity Power Factor Loads.
    • Paweł Szczepankowski
    2022 Pełny tekst IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS

    This paper proposes a novel PWM modulation algorithm for Multiphase Conventional Matrix Converters (MCMC), with 3 inputs and k outputs, using the transfer function of the load angle. The proposed approach extends the range of power angle control at the input during the operation with a maximum voltage transfer ratio. The proposed concept is based on the Direct Analytic Voltage PWM (DAV--PWM) modulation with an elliptical trajectory of reference load voltages. The proposal has been verified using the circuit simulation in PSIM software, symbolic analysis using Matlab, and finally through an experiment.

  • An Innovative Antenna Array with High Inter Element Isolation for Sub-6 GHz 5G MIMO Communication Systems
    • Mohammad Alibakhshikenari
    • Bal S. Virdee
    • Harry Benetatos
    • Esraa Mousra Ali
    • Mohammad Soruri
    • Mariana Dalarsson
    • Mohammad Naser-moghadasi
    • Chan Hwang See
    • Anna Pietrenko-Dąbrowska
    • Mateusz Kozieł
    • Stanisław Szczepański
    • Ernesto Limiti
    2022 Pełny tekst Scientific Reports

    A novel technique is shown to improve the isolation between radiators in antenna arrays. The proposed technique suppresses the surface-wave propagation and reduces substrate loss thereby enhancing the overall performance of the array. This is achieved without affecting the antenna’s footprint. The proposed approach is demonstrated on a four-element array for 5G MIMO applications. Each radiating element in the array is constituted from a 3×3 matrix of interconnected resonant elements. The technique involves (i) incorporating matching stubs within the resonant elements, (ii) framing each of the four-radiating elements inside a dot-wall, and (iii) defecting the ground plane with dielectric slots that are aligned under the dot-walls. Results show that with the proposed approach the impedance bandwidth of the array is increased by 58.82% and the improvement in the average isolation between antennas #1&2, #1&3, #1&4 are 8 dB, 14 dB, 16 dB, and 13 dB, respectively. Moreover, improvement in the antenna gain is 4.2% and the total radiation efficiency is 23.53%. These results confirm the efficacy of the technique. The agreement between the simulated and measured results is excellent. Furthermore, the manufacture of the antenna array using the proposed approach is relatively straightforward and cost effective.

  • An innovative method of measuring the extension of the piston rod in hydraulic cylinders, especially large ones used in the shipbuilding and offshore industry
    • Czesław Dymarski
    • Paweł Dymarski
    • Piotr Grymajło
    2022 Pełny tekst Polish Maritime Research

    The article presents the results of selected works related to the wider subject of research conducted at the Faculty of Mechanical Engineering and Shipbuilding at the Gdańsk University of Technology, regarding designing various on board devices with hydraulic drive for ships and other offshore facilities. One of the commonly used these mechanisms are hydraulic actuators with the measurement of the piston rod extension. The issue of precise measurement of the piston rod extension is extremely important in modern technologies of construction, assembly and precise displacement and positioning of large and heavy, both land and ocean engineering objects or structural elements with the use of several large hydraulic cylinders working in parallel. The article presents a one of two new patented P.425099 – A device for measuring the extension of a hydraulic cylinder piston rod. [1].

  • An investigation on residual stress and fatigue life assessment of T-shape welded joints
    • Farzaneh Samadi
    • Jeetendra Mourya
    • Greg Wheatley
    • Mohammed Nizam Khan
    • Reza Masoudi Nejad
    • Ricardo Branco
    • Wojciech Macek
    2022 Pełny tekst ENGINEERING FAILURE ANALYSIS

    This paper aims to quantitatively evaluate the residual stress and fatigue life of T-type welded joints with a multi-pass weld in different direction. The main research objectives of the experimental test were to test the residual stress by changing direction along with multiple wielding passes and determine the fatigue life of the welded joints. The result shows that compressive residual stress increases in the sample gradually from single-pass weld to double and triple-pass weld. Moreover, the fatigue life of the specimen also gradually improves with an increasing number of welding passes. Performing multi-pass welding in different directions affects the material’s residual stress and fatigue life, which is an essential factor to consider for assuring the strength of the welded joint.

  • An isogeometric finite element formulation for boundary and shell viscoelasticity based on a multiplicative surface deformation split
    • Karsten Paul
    • Roger Sauer
    2022 Pełny tekst INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING

    This work presents a numerical formulation to model isotropic viscoelastic material behavior for membranes and thin shells. The surface and the shell theory are formulated within a curvilinear coordinate system,which allows the representation of general surfaces and deformations. The kinematics follow from Kirchhoff–Love theory and the discretization makes use of isogeometric shape functions. A multiplicative split of the surface deformation gradient is employed, such that an intermediate surface configuration is introduced. The surface metric and curvature of this intermediate configuration follow from the solution of nonlinear evolution laws—ordinary differential equations—that stem from a generalized viscoelastic solid model. The evolution laws are integrated numerically with the implicit Euler scheme and linearized within the Newton–Raphson scheme of the nonlinear finite element framework. The implementation of membrane and bending viscosity is verified with the help of analytical solutions and shows ideal convergence behavior. The chosen numerical examples capture large deformations and typical viscoelasticity behavior, such as creep, relaxation, and strain rate dependence. It is also shown that the proposed formulation can be straightforwardly applied to model boundary viscoelasticity of 3D bodies.

  • An isogeometric finite element formulation for frictionless contact of Cosserat rods with unconstrained directors
    • Myung-Jin Choi
    • Sven Klinkel
    • Roger Sauer
    2022 Pełny tekst COMPUTATIONAL MECHANICS

    This paper presents an isogeometric finite element formulation for nonlinear beams with impenetrability constraints, based on the kinematics of Cosserat rods with unconstrained directors. The beam cross-sectional deformation is represented by director vectors of an arbitrary order. For the frictionless lateral beam-to-beam contact, a surface-to-surface contact algorithm combined with an active set strategy and a penalty method is employed. The lateral boundary surface of the beam is parameterized by its axis and cross-sectional boundary curves with NURBS basis functions having at leastC2-continuity,which yields a continuous surface metric and curvature for the closest point projection. Three-dimensional constitutive laws of hyperelastic materials are considered. Several numerical examples verify the accuracy and efficiency of the proposed beam contact formulation in comparison to brick element solutions. The lateral contact pressure distribution of the beam formulation is in excellent agreement with the contact pressure of the brick element formulation while requiring much less degrees-of-freedom.

  • An MOR Algorithm Based on the Immittance Zero and Pole Eigenvectors for Fast FEM Simulations of Two-Port Microwave Structures
    • Grzegorz Fotyga
    • Damian Szypulski
    • Adam Lamęcki
    • Piotr Sypek
    • Michał Rewieński
    • Valentin de la Rubia
    • Michał Mrozowski
    2022 Pełny tekst IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES

    The aim of this article is to present a novel model-order reduction (MOR) algorithm for fast finite-element frequency-domain simulations of microwave two-port structures. The projection basis used to construct the reduced-order model (ROM) comprises two sets: singular vectors and regular vectors. The first set is composed of the eigenvectors associated with the poles of the finite-element method (FEM) state-space system, while the second one is made up from the eigenvectors corresponding to the zeros of the diagonal elements of the matrix-valued immittance transfer function. Importantly, just one LU factorization of the FEM system is required to construct the projection basis during the reduction process, due to the application of a new formulation based on the Schur complement. The sets of eigenvectors that are used in the basis are independent of one another, which makes the new technique better suited for parallel computing compared with previously developed methods, which are sequential in nature. The reliability and accuracy of the proposed scheme are compared with that of the standard MOR technique, namely, the reduced-basis method (RBM), and verified through the analysis of three microwave structures: an eighth-order dual-mode waveguide filter, a dielectric resonator filter, and a folded waveguide filter.

  • An observability and detectability analysis for non-linear uncertain CSTR model of biochemical processes
    • Mateusz Czyżniewski
    • Rafał Łangowski
    2022 Pełny tekst Scientific Reports

    The problem of proving observability/detectability properties for selected non-linear uncertain model of biochemical processes has been addressed in this paper. In particular, the analysis of observability/detectability in the face of parametric and unstructured uncertainty in system dynamics transformed into unknown inputs, and unknown initial conditions has been performed. Various sets of system measured outputs were taken into account during the research. The considered biochemical processes were modelled as a continuous stirred tank reactor with the microbial growth reaction and microbial mortality with the aggregated substrate and biomass concentrations in aerobic phase. Classical tools based on differential geometry and the method of indistinguishable state trajectories (indistinguishable dynamics) were used to verify the properties of the system. The observability/detectability analysis was performed for nine cases covering a wide range of possible combinations of system measured outputs and unknown inputs. The obtained results of are crucial meaning for system state reconstruction (estimation), which involves the synthesis of state observers.

  • An optimal designed experiment for the alkaline hydrolysis of feather keratin
    • Małgorzata Dąbrowska
    • Agata Sommer
    • Izabela Sinkiewicz
    • Antoni Taraszkiewicz
    • Hanna Staroszczyk
    2022 Pełny tekst ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

    Feathers, burdensome waste from the poultry industry, can be a cheap source of keratin, a protein with excellent physico- chemical, biological, and mechanical properties. Acid and alkaline hydrolyses are usually adopted for isolation of keratin from its natural resources. This study aimed at assessing the statistically significant effect of input variables in the alkaline hydrolysis of keratin from chicken feathers on the process yield and on the molecular weight of peptides obtained. The effect of the volume ratio of 1M NaOH to the feathers’ mass, the hydrolysis time, and the shaking speed of the reaction mixture on the process yield were analyzed. The use of statistical analysis at the design step of experiment allowed reducing the trial number from 27 to 9. Among the input variables analyzed, only the volume ratio of 1M NaOH to the feathers’ mass had a significant effect on the process yield, while none of them significantly affected the molecular weight of the peptides obtained. All hydrolysates were dominated by two peptides’ fractions, with molecular weights of ca. 130 and 250 kDa, and mixture of many peptides of weight close to 10 kDa and smaller. Alkaline hydrolysis of feather keratin yielded protein hydrolysates soluble over a wide pH range.

  • An optimal form of the finite element mass matrix in the analysis of longitudinal vibrations of rods
    • Magdalena Palacz
    • Marek Krawczuk
    2022 Pełny tekst FINITE ELEMENTS IN ANALYSIS AND DESIGN

    In this paper, an attempt is made to find the optimal form of the mass matrix of a rod finite element, which allows one to obtain the smallest errors in the longitudinal frequency determination of natural vibrations of any boundary conditions within the whole range of determined frequencies. It is assumed that the mass matrix can be treated as a linear combination of the consistent and diagonal matrices. Based on analytical considerations, the optimal values of certain weights for creating a linear combination of the mentioned matrices have been determined. As a result, a mass matrix has been obtained which allows the determination of natural frequencies with the smallest mean error within the possible spectrum of frequencies. It is also shown that the value of the weight coefficient changes depending on the number of natural frequencies within the spectrum one wants to determine.

  • AN OVERVIEW OF HEAT TRANSFER ENHANCEMENT BASED UPON NANOPARTICLES INFLUENCED BY INDUCED MAGNETIC FIELD WITH SLIP CONDITION VIA FINITE ELEMENT STRATEGY
    • Muhammad Bilal Hafeez
    • Marek Krawczuk
    • Hasan Shahzad
    2022 Pełny tekst Acta Mechanica et Automatica

    The mathematical model of heat generation and dissipation during thermal energy transmission employing nanoparticles in a Newtonian medium is investigated. Dimensionless boundary layer equations with correlations for titanium dioxide, copper oxide, and aluminium oxide are solved by the finite element method. Parameters are varied to analyze their impact on the flow fields. Various numerical experiments are performed consecutively to explore the phenomenon of thermal performance of the combination fluid. A remarkable enhancement in thermal performance is noticed when solid structures are dispersed in the working fluid. The Biot number determines the convective nature of the boundary. When the Biot number is increased, the fluid temperature decreases significantly. Among copper oxide, aluminium oxide, and titanium oxide nanoparticles, copper oxide nanoparticles are found to be the most effective thermal enhancers.

  • An Overview of Treatment Approaches for Octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX) Explosive in Soil, Groundwater, and Wastewater
    • Varsha Srivastava
    • Grzegorz Boczkaj
    • Ulla Lassi
    2022 Pełny tekst International Journal of Environmental Research and Public Health

    Octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX) is extensively exploited in the manufacturing of explosives; therefore, a significant level of HMX contamination can be encountered near explosive production plants. For instance, up to 12 ppm HMX concentrations have been observed in the wastewater effluent of a munitions manufacturing facility, while up to 45,000 mg/kg of HMX has been found in a soil sample taken from a location close to a high-explosive production site. Owing to their immense demand for a variety of applications, the large-scale production of explosives has culminated in severe environmental issues. Soil and water contaminated with HMX can pose a detrimental impact on flora and fauna and hence, remediation of HMX is paramount. There is a rising demand to establish a sustainable technology for HMX abatement. Physiochemical and bioremediation approaches have been employed to treat HMX in the soil, groundwater, and wastewater. It has been revealed that treatment methods such as photo-peroxidation and photo-Fenton oxidation can eliminate approximately 98% of HMX from wastewater. Fenton’s reagents were found to be very effective at mineralizing HMX. In the photocatalytic degradation of HMX, approximately 59% TOC removal was achieved by using a TiO2 photocatalyst, and a dextrose co-substrate was used in a bioremediation approach to accomplish 98.5% HMX degradation under anaerobic conditions. However, each technology has some pros and cons which need to be taken into consideration when choosing an HMX remediation approach. In this review, various physiochemical and bioremediation approaches are considered and the mechanism of HMX degradation is discussed. Further, the advantages and disadvantages of the technologies are also discussed along with the challenges of HMX treatment technologies, thus giving an overview of the HMX remediation strategies.

  • An updated method identifying collision-prone locations for ships. A case study for oil tankers navigating in the Gulf of Finland
    • J. Mazurek
    • L. Lu
    • Przemysław Krata
    • Jakub Montewka
    • H. Krata
    • Pentti Kujala
    2022 Pełny tekst RELIABILITY ENGINEERING & SYSTEM SAFETY

    To ensure the risk level associated with continuously increasing maritime traffic through particularly sensitive sea areas remains at acceptable level, a periodic risk assessment needs to be carried out by the relevant authorities. As a part of such assessment, allowing for proactive countermeasures to mitigate risk, the frequency of accidents is estimated along with the assessment of geographical locations where the accidents are most likely to happen. To this end scientific literature offers a number of approaches, however only a few solutions are recognized by the maritime authorities and applied world-wide. One of such approach is a evidence-based, semi-dynamic, network-based model called IWRAP Mk2. Despite its advantages, the tool lacks the verification procedure of the model development process that governs the reliability of the results. This ultimately may undermine the reliability of the obtained results. This shortcoming seems to be quite common in the field of maritime risk assessment, as revealed by the recent analysis of the risk assessment method and tools. Therefore, this article attempts to close this knowledge gap by providing a novel framework for ship-ship collision probability estimation and identification of the collision-prone locations, encompassing novel verification procedure suitable for network-based maritime risk models such as IWRAP Mk2 tool. As a results this new, wider modeling framework offers more reliable, evidence-based estimates of the probability of ship-ship collision and identifies more accurately the collision-prone locations in a given sea area. To demonstrate the usability of the framework a case study is performed, with the use of 10 months of ship traffic data recorded in the heavily trafficked and enclosed sea area of the Gulf of Finland during ice-free season with the special attention paid to the oil tankers. The updated framework delivers the annual probability of ship-ship collision, where at least one ship is an oil tanker, which is higher by 16% compared to the results obtained from regular IWRAP Mk2 software, that lacks verification procedure. Also the framework identifies the most collision-prone locations in the Gulf of Finland, which are located in the eastern part of the Gulf, explaining over 60% of the total collisions in the whole GoF, for ice-free seasons.

  • Analityka związków chemicznych z grupy bisfenoli w próbkach o skomplikowanym składzie matrycy, w tym pochodzenia biologicznego
    • Katarzyna Owczarek
    2022 Pełny tekst

    Bisfenol A jest substancja produkowaną globalnie na ogromną skalę. Używany jest w produkcji opakowań do żywności, papieru termalnego, wypełnień dentystycznych i całej gamy innych przedmiotów, z którymi człowiek ma na co dzień kontakt. Ze względu na stosunkowo dobrze poznane mechanizmy jego szkodliwego działania, zarówno w kontekście zdrowia ludzkiego jak i dobrostanu ekosystemów, przemysłowe zastosowanie tego związku podlega szeregowi uregulowań prawnych. Konsekwencją takiego stanu rzeczy było poszukiwanie przez przemysł tworzyw sztucznych zamienników BPA, w tym jego analogów charakteryzujących się podobną strukturą chemiczną. Ich działanie na organizm, a także konsekwencje ich pojawienia się w środowisku nie są dostatecznie dobrze poznane. W niniejszej pracy doktorskiej poświęcono uwagę badaniom toksyczności ostrej szeregu wybranych związków z grupy bisfenoli, ich wzajemnym oddziaływaniom w mieszaninach dwuskładnikowych a także opracowaniu miarodajnych, czułych i nowoczesnych analitycznych metod instrumentalnych, służących do oznaczania bisfenoli w próbkach różnego pochodzenia charakteryzujących się skomplikowanym składem matrycy. Uzyskane wyniki badań poszczególnych analogów BPA wskazują na potencjał endokrynny o podobnej lub nawet większej sile, w relacji do BPA, a także na stały, uporczywy i nieunikniony kontakt człowieka oraz innych organizmów żywych z ta grupą substancji.

  • Analiza doświadczalna wpływu średnicy pręta na przyczepność w teście pull-out
    • Marcin Burdziński
    • Maciej Niedostatkiewicz
    2022 Pełny tekst Materiały Budowlane

    W artykule zaprezentowano analizę doświadczalną przyczepności, która miała na celu ocenę wpływu średnicy pręta na przyczepność w probie pull-out. Ponadto zweryfikowano wybrane modele analityczne wyznaczające wytrzymałość przyczepności w stosunku do otrzymanych rezultatów z testów. Z wykonanej analizy wynika, że średnica pręta istotnie wpływa na zachowanie przyczepności. Przytoczone modele w rożnym stopniu zbieżności oszacowują wartości otrzymane z zaprezentowanych badań.

  • ANALIZA EFEKTYWNOŚCI METOD GŁĘBOKIEGO UCZENIA W ODBIORZE SYGNAŁÓW GMSK
    • Alicja Olejniczak
    • Krzysztof Cwalina
    • Jarosław Sadowski
    • Jacek Stefański
    2022 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Sztuczna inteligencja odnajduje coraz szersze zastosowanie we współczesnej radiokomunikacji, choć głównie w ujęciu badawczym. Niniejszy artykuł przedstawia przegląd i ewaluację metod z obszaru głębokiego uczenia umożliwiających detekcję sygnałów z modulacją GMSK (ang. Gaussian Minimum Shift Keying) w kanale AWGN. Badane modele porównane zostały z optymalnym detektorem pracującym zgodnie z regułą największej wiarygodności MLSE (ang. Maximum Likelihood Sequence Estimation), a miarą oceny efektywności była bitowa stopa błędu.

  • Analiza jakości transmisji treści audio-wideo w symulowanym łączu telekomunikacyjnym z wykorzystaniem techniki OFDM
    • Monika Zamłyńska
    • Przemysław Falkowski-Gilski
    2022 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    Wdrożenie niezawodnego systemu komunikacji audio-wideo przynosi wiele korzyści. Z uwagi na fakt, że ilość dostępnego pasma stale się kurczy, badacze koncentrują się na nowatorskich metodach transmisji. Obecnie technika OFDM (Orthogonal Frequency Division Multiplexing) jest szeroko stosowana zarówno w mediach przewodowych, jak i bezprzewodowych. W pracy przedstawiono badania jakości QoS (Quality of Service) symulowanego łącza transmisji danych, przy zmiennych poziomach SNR (Signal-to-Noise Ratio) oraz BER (Bit Error Rate).

  • ANALIZA METOD SYNCHRONIZACJI W SIECI NB-IOT
    • Olga Błaszkiewicz
    • Piotr Rajchowski
    • Jarosław Sadowski
    2022 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    W artykule zaprezentowano przegląd i analizę metod synchronizacji odbiornika w sieci NB-IoT. Zaimplementowano trzy metody synchronizacji, a ich porównania dokonano na bazie rzeczywistych sygnałów NB-IoT wygenerowanych przy użyciu testera radiokomunikacyjnego w wyizolowanym i emulowanym środowisku propagacyjnym.

  • Analiza możliwości rozwoju Mieszkalnych Obiektów Pływających (MOP) w aspekcie czynników środowiskowych
    • Emilia Miszewska
    • Maciej Niedostatkiewicz
    • Radosław Wiśniewski
    2022 Pełny tekst Przegląd Budowlany

    W publikacji przestawiono wyniki badań dotyczących możliwości rozwoju Mieszkalnych Obiektów Pływających (MOP), popularnie nazywanych Domami Na Wodzie (DNW) z uwzględnieniem wpływu czynników środowiskowych. Badanie potencjalnych kierunków rozwoju MOP w aspekcie czynników środowiskowych przeprowadzone zostało z zastosowaniem metody Scenariuszy Stanów Otoczenia dla scenariusza optymistycznego, pesymistycznego i najbardziej prawdopodobnego. Opracowane scenariusze pozwoliły określić burzliwość otoczenia, jego niejednorodność i procesy wiodące w rozwoju MOP w Polsce.

  • Analiza następstw potencjalnej awarii wanty mostu podwieszonego w Bydgoszczy
    • Krzysztof Żółtowski
    • Przemysław Kalitowski
    2022 Pełny tekst Materiały Budowlane

    Most Uniwersytecki został zamknięty po siedmiu latach od oddania do użytkowania. Powodem były widoczne gołym okiem objawy znacznego przeciążenia w obrębie zakotwień. Krytyczne elementy konstrukcji mostu zostały wzmocnione i przywrócono go do ruchu. W artykule przedstawiono nieliniowe analizy statyczne i dynamiczne wykonane na modelu MES, prezentujące cztery scenariusze przebiegu zachowania konstrukcji po utracie nośności mocowania wanty. Wykazały one, że przy przyjętych założeniach urwanie jednej z want prowadziłoby do nieuchronnej katastrofy.

  • Analiza porównawcza sposobów wyznaczania obciążeń wiatrem na podstawie norm projektowych i analizy przepływu CFD
    • Robert Okoński
    • Andrzej Ambroziak
    2022 Pełny tekst Przegląd Budowlany

    W pracy poruszono tematykę wykorzystania analizy przepływu CFD do wyznaczania obciążeń wiatru na konstrukcje. Przedstawiono analizę trzech modeli budynków o dachu dwuspadowym o różnych kątach nachylenia, dla których dokonano porównania wielkości współczynników parcia z wynikami dostępnymi w literaurze. Obliczenia analityczne wykonano zgodnie z normą z PN-EN 1991-1-4, natomiast obliczenia numeryczne wykonano w programie R-Wind Simulation. Całość wyników podsumowano, a wnioski sformułowano w odniesieniu do tematyki rozwiązania problemu szacowania wielkości obciążenia wiatru działającego na konstrukcję.

  • Analiza przyczepności prętów żebrowanych w betonie metodą pull-out na próbkach centrycznych i mimośrodowych
    • Marcin Burdziński
    • Maciej Niedostatkiewicz
    2022 Pełny tekst Przegląd Budowlany

    Artykuł dotyczy analizy przyczepności żebrowanego stalowego pręta zbrojeniowego w betonie. Celem pracy była ocena wpływu położenia pręta w betonowym bloku na lokalną zależność naprężenie przyczepności-poślizg. Podjęto także próbę numerycznej symulacji przeprowadzonych eksperymentów w programie ABAQUS. Analizę doświadczalną przeprowadzono za pomocą testu pull-out na dwóch rodzajach próbek – centrycznych i mimośrodowych w dwóch wariantach, z dolnym otuleniem o grubości 20 i 40 mm. Do obliczeń numerycznych wykorzystano modele materiałowe odpowiadające materiałom zastosowanym w doświadczeniach. Użyto modelu betonu plastycznego ze zniszczeniem (ang. Concrete Damaged Plasticity) oraz modelu liniowo-sprężystego dla stali. Przeprowadzone eksperymenty potwierdziły, że zmiana lokalizacji pręta na kierunku pionowym wpływa na zmniejszenie jego skrępowania w betonie, co rzutuje na redukcję wartości maksymalnych naprężeń przyczepności oraz na mechanizm zniszczenia, czego konsekwencją jest zmiana przebiegu krzywej naprężenie przyczepności-poślizg względem próbek centrycznych. Wykonane symulacje MES poprawnie odwzorowują zachowanie przyczepności w próbkach podczas testów pull-out.

  • ANALIZA STATECZNOŚCI ORAZ KONCEPCJA ZABEZPIECZENIA ZBOCZA OSUWISKOWEGO W MOSTKACH K. STAREGO SĄCZA
    • Lesław Zabuski
    • Jarosław Przewłócki
    2022 Rozprawy Naukowe i Zawodowe Państwowej Wyższej Szkoły Zawodowej w Elblągu

    W artykule przedstawiano analizę warunków stateczności zbocza osuwiskowego w miejscowości Mostki k. Starego Sącza, wraz ze sprawdzeniem efektywności zabezpieczenia zbocza przy zastosowaniu środków stabilizujących. Dla ustabilizowania zbocza zaproponowano jego drenowanie (drenaż podziemny) oraz „podparcie” przegrodą z mikropali. Rozważano stan stateczności zbocza w warunkach ekstremalnie niekorzystnych - gdy zwierciadło wody podziemnej (ZWP) osiąga poziom powierzchni terenu oraz po zastosowaniu środków stabilizujących.

  • Analiza współczynnika dyskryminacji polaryzacji skrośnej dla sieci ban w cylindrycznym środowisku rewerberacyjnym
    • Sławomir Ambroziak
    • Krzysztof Cwalina
    • Piotr Rajchowski
    2022 Pełny tekst

    W referacie przedstawiono analizę współczynnika dyskryminacji po-laryzacji skrośnej XPD dla sieci nasobnych BAN pracujących w cylin-drycznym środowisku rewerberacyjnym. Analiza została przeprowadzona na podstawie wyników badań pomiarowych wąskopasmowego kanału radio-wego typu off-body na częstotliwości 2,45 GHz. Dowiedziono, że występuje zależność wartości współczynnika dyskryminacji polaryzacji skrośnej od istnienia składowej bezpośredniej sygnału odbieranego.

  • ANALIZA ZANIKÓW SZYBKOZMIENNYCH W RADIOWYCH SIECIACH BAN PRACUJĄCYCH W REWERBERACYJNYM ŚRODOWISKU PROPAGACYJNYM
    • Sławomir Ambroziak
    • Filipe D. Cardoso
    • Paweł Kosz
    • Manuel M. Ferreira
    • Luis M. Correia
    2022 Pełny tekst Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    W referacie przedstawiono badania i analizę zaników szybkozmiennych występujących w sieciach BAN, pracujących na częstotliwości 2,45 GHz w środowisku zamkniętym o kształcie cylindrycznym z metalowymi ścianami. Badania przeprowadzono przy użyciu symulatora zweryfikowanego pomiarowo. Uzyskane wyniki wskazują, że w analizowanym środowisku propagacyjnym zaniki szybkozmienne można modelować przy pomocy rozkładu Rayleigha, nawet w przypadku występowania warunków bezpośredniej widoczności anten łącza radiowego.

  • Analyses of Shear Angle in Orthogonal Cutting of Pine Wood
    • Kazimierz Orłowski
    • Daniel Chuchała
    • Gerhard Sinn
    2022 Pełny tekst Drvna Industrija

    The determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The pine wood analysed was represented by two groups of samples with different moisture content levels, 12 % and 20 %. Three different models were used to determine the shear angle values: the Merchant model, which is based on the rake angle and the angle of friction, model based on chip compression ratios and Atkins model based on material properties (elements of fracture mechanics). The values obtained have been analysed for comparison. Results showed that the values of the shearing angles determined from the chip compression ratios turned out to be higher than the values from Merchant equation. The shear angles determined from the Atkins model are, as expected, lower than those determined from the Merchant model. Furthermore, the shear angle values for moisture content of 20 % are higher than for moisture content of 12 %.

  • Analysing By-Products Interaction as an Industry Resource of Circular Economy in Ukraine and the World
    • Myroslava Bublyk
    • Vadym Shandurskyi
    • Taras Machita
    • Piotr Grudowski
    • Oleksandr Pavlyuk
    2022

    The paper analyses existing and current scientific developments and literature sources, which show the advantages and disadvantages of many different influences of waste in Ukraine and other countries of Europe and the world. As a research result, stable connections have been established between the factors and criteria in assessing the by-product interaction as an industry resource. In our research, we used programs R.Studio and Power BI Desktop, and language programming R. Analysis dataset conducted by help such diagrams as Histogram, Pie Charts. Based on the analysis diagrams, we conducted our analysis, where we determined the main factors and criteria.

  • Analysing the Residential Market Using Self-Organizing Map
    • Olgun Aydin
    • Krystian Zieliński
    2022

    Although the residential property market has strong connections with various sectors, such as construction, logistics, and investment, it works through different dynamics than other markets; thus, it can be analysed from various perspectives. Researchers and investors are mostly interested in price trends, the impact of external factors on residential property prices, and price prediction. When analysing price trends, it is beneficial to consider multidimensional data that contain attributes of residential properties, such as number of rooms, number of bathrooms, floor number, total floors, and size, as well as proximity to public transport, shops, and banks. Knowing a neighbourhood’s key aspects and properties could help investors, real estate development companies, and people looking to buy or rent properties to investigate similar neighbourhoods that may have unusual price trends. In this study, the self-organizing map method was applied to residential property listings in the Trójmiasto Area of Poland, where the residential market has recently been quite active. The study aims to group together neighbourhoods and subregions to find similarities between them in terms of price trends and stock. Moreover, this study presents relationships between attributes of residential properties.

  • Analysis of Agricultural and Engineering Systems using Simulation Decomposition
    • Yen-Chen Liu
    • Leifur Leifsson
    • Anna Pietrenko-Dąbrowska
    • Sławomir Kozieł
    2022

    This paper focuses on the analysis of agricultural and engineering processes using simulation decomposition (SD). SD is a technique that utilizes Monte Carlo simulations and distribution decomposition to visually evaluate the source and the outcome of different portions of data. Here, SD is applied to three distinct processes: a model problem, a nondestructive evaluation testing system, and an agricultural food-water energy system. The results demonstrate successful implementations of SD for the different systems, and the illustrate the potential of SD to support new understanding of cause and effect relationships in complex systems.

  • Analysis of an Energy Management System of a Small Plant Connected to the Rural Power System
    • Mirosław Włas
    • Stanisław Galla
    • Abdellah Kouzou
    • Piotr Kołodziejek
    2022 Pełny tekst ENERGIES

    This paper presents the analysis of an energy management system (EMS) implemented to fulfill the requirements of a microgrid (MG) power supply owned by a small industrial company and connected to the rural power system. The main goal of this system is to ensure connection with the existing rural power system in terms of energy exchange, as well as to perform islanding mode operation of the microgrid based on the energy demand of the company. Power generated in the implemented microgrid is based on a hybrid system supported by renewable energy sources and an energy storage system. The aim of the developed energy management system implemented in this MG power system is to enable the microgrid to operate according to scheduled diagrams related to different load events. The presented investigation, analysis, and assessment of the implemented energy management system are based on the on-site measurements and observations of the longterm operation of the microgrid concerning the hybrid renewable energy-based generation system and the company energy demand, which is useful from perspective of the predicted deficiency of electrical energy in Poland, both for customers and transmission system operators. Furthermore, the observed drawbacks and failures of the implemented EMS and the MG are pointed out and discussed to overcome and minimize these disadvantages, and to improve the operational reliability of the whole system.

  • Analysis of data fusion algorithms for the vessel with the dynamic positioning system
    • Krzysztof Jaroś
    • Roman Śmierzchalski
    • Anna Witkowska
    2022 Pełny tekst Przegląd Elektrotechniczny

    The dynamic positioning (DP) system on the vessel is operated to control the position and heading of the vessel with the use of propellers and thrusters installed on the board. On DP vessels redundant measurement systems of position, heading and the magnitude and direction of environmental forces are required for safety at sea. In this case, a fusion of data is needed from individual measurement devices. The article proposes a new solution data fusion algorithm of particle Kalman filter as a cascade combination of particle filter and extended Kalman filter. The estimation quality of the proposed data fusion algorithm is analysed in comparison with the classic: extended Kalman filter (EKF), nonlinear observer (NO), and particle Kalman filter (PKF). Simulation studies were executed for emergency scenarios to evaluate the robustness of the algorithm analyses to measurement errors.