2022 - Repozytorium publikacji - Politechnika Gdańska

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Additive Manufacturing as a Solution to Challenges Associated with Heat Pipe Production
- Paweł Szymański
- Dariusz Mikielewicz
2022 Pełny tekst Materials
The aim of this review is to present the recent developments in heat pipe production, which respond to the current technical problems related to the wide implementation of this technology. A novel approach in HP manufacturing is to utilise hi-tech additive manufacturing techniques where the most complicated geometries are fabricated layer-by-layer directly from a digital file. This technology might be a solution to various challenges that exist in HP production, i.e., (1) manufacturing of complex or unusual geometries HPs; (2) manufacturing complicated and efficient homogenous wick structures with desired porosity, uniform pore sizes, permeability, thickness and where the pores are evenly distributed; (3) manufacturing a gravity friendly wick structures; (4) high customisation and production time; (5) high costs; (6) difficulties in the integration of the HP into a unit chassis that enables direct thermal management of heated element and decrease its total thermal resistance; (7) high weight and material use of the part; (8) difficulties in sealing; (9) deformation of the flat shape HPs caused by the high pressure and uneven distribution of stress in the casing, among others.
Adjusting the Stiffness of Supports during Milling of a Large-Size Workpiece Using the Salp Swarm Algorithm
- Krzysztof Kaliński
- Marek Galewski
- Natalia Stawicka-Morawska
- Michał Mazur
- Arkadiusz Parus
2022 Pełny tekst SENSORS
This paper concerns the problem of vibration reduction during milling. For this purpose, it is proposed that the standard supports of the workpiece be replaced with adjustable stiffness supports. This affects the modal parameters of the whole system, i.e., object and its supports, which is essential from the point of view of the relative tool–workpiece vibrations. To reduce the vibration level during milling, it is necessary to appropriately set the support stiffness coefficients, which are obtained from numerous milling process simulations. The simulations utilize the model of the workpiece with adjustable supports in the convention of a Finite Element Model (FEM) and a dynamic model of the milling process. The FEM parameters are tuned based on modal tests of the actual workpiece. For assessing simulation results, the proper indicator of vibration level must be selected, which is also discussed in the paper. However, simulating the milling process is time consuming and the total number of simulations needed to search the entire available range of support stiffness coefficients is large. To overcome this issue, the artificial intelligence salp swarm algorithm is used. Finally, for the best combination of stiffness coefficients, the vibration reduction is obtained and a significant reduction in search time for determining the support settings makes the approach proposed in the paper attractive from the point of view of practical applications.
Advanced Control With PLC—Code Generator for aMPC Controller Implementation and Cooperation With External Computational Server for Dealing With Multidimensionality, Constraints and LMI Based Robustness
- Jarosław Tarnawski
- Piotr Kudełka
- Mateusz Korzeniowski
2022 Pełny tekst IEEE Access
The manufacturers of Programmable Logic Controllers (PLC) usually equip their products with extremely simple control algorithms, such as PID and on-off regulators. However, modern PLCs have much more efficient processors and extensive memory, which enables implementing more sophisticated controllers. The paper discusses issues related to the implementation of matrix operations, time limitations for code execution within one PLC cycle, and memory requirements. The adaptive Model Predictive Controller (aMPC) algorithm is selected for predictive control with on-line adaptation of model parameters. The combination of predictive and adaptive properties in the regulator enables control of many industrial objects for which PID control is ineffective, e.g. nonstationary plants with time-varying delays. The presented generic approach consists in developing a C++ application for desktop PC that generates, based on user provided parameters - such as MPC horizons, the code in Structured Text (ST) language compliant with the IEC-61131 standard for PLCs. Despite the enhanced capabilities of programmable controllers, there are limitations to this platform that cannot be overcome. The implementation of optimization-based control algorithms requires cooperation with an external computing server. In the article, the PLC/external computer cooperation is used to implement the control with constraints taken into account. The robust control using the Linear Matrix Inequalities (LMI) for a multivariable plant is also presented. A number of tests were carried out to verify the correctness of implementation of this control in software-in-the-loop and hardware-in-the-loop structures.
Advanced oxidation processes (AOPs) based wastewater treatment - unexpected nitration side reactions - a serious environmental issue: A review
- Manoj Panayamthatta Rayaroth
- Charuvila T. Aravindakumar
- Noor S. Shah
- Grzegorz Boczkaj
2022 Pełny tekst CHEMICAL ENGINEERING JOURNAL
Chemical compounds containing nitro group (nitro-products) are a one of toxic by-products, that can be formed during wastewater treatment processes. In case of presence of nitrite or nitrate ions, the formation of nitro-products during advanced oxidation processes (AOPs) is very common. It is caused by the reactive nitrogen species (RNs) such as nitrate radical (NO3•), nitrite radical (NO2•), nitrogen oxide radical (NO•) and peroxynirite (ONOO–). In fact, the oxidative degradation of N-containing pollutants releases nitrate, nitrite and ammonium ions. In some cases, secondary reactions of mineralised nitrogen species (nitrate and nitrite ions) with the parent or intermediate compound generate next several nitro-products. The nitro-products are more toxic comparing to the primary pollutants and act as the precursors of the nitrogenous disinfection by-products. Moreover, some studies reported unexpected nitro-products formation during the oxidative degradation. In case of such processes a special attention should be made to monitor and minimize these effects. De-nitration of the initial nitro-compounds induces the formation of various nitro-products in AOPs. It was observed for UV light driven, Fenton and persulfate based AOPs. The sonochemical nitrogen fixation is a key mechanism for the formation of nitro-compounds in ultrasounds based AOPs. Therefore, this paper is focused on comparison of various AOPs in terms of nitro-products formation mechanisms and the associated environmental issues.
Advancements in the Additive Manufacturing of Magnesium and Aluminum Alloys through Laser-Based Approach
- Sachin Kumar Sharma
- Harpreet Singh Grewal
- Kuldeep Kumar Saxena
- Kahtan A. Mohammed
- Chander Prakash
- J. Paulo Davim
- Dharam Buddhi
- Ramesh Raju
- Dhanesh G. Mohan
- Jacek Tomków
2022 Pełny tekst Materials
Complex structures can now be manufactured easily utilizing AM technologies to meet the pre-requisite objectives such as reduced part numbers, greater functionality, and lightweight, among others. Polymers, metals, and ceramics are the few materials that can be used in AM technology, but metallic materials (Magnesium and Aluminum) are attracting more attention from the research and industrial point of view. Understanding the role processing parameters of laser-based additive manufacturing is critical to maximize the usage of material in forming the product geometry. LPBF (Laser powder-based fusion) method is regarded as a potent and effective additive manufacturing technique for creating intricate 3D forms/parts with high levels of precision and reproducibility together with acceptable metallurgical characteristics. While dealing with LBPF, some degree of porosity is acceptable because it is unavoidable; hot ripping and cracking must be avoided, though. The necessary manufacturing of pre-alloyed powder and ductility remains to be the primary concern while dealing with a laser-based additive manufacturing approach. The presence of the Al-Si eutectic phase in AlSi10Mg and AlSi12 alloy attributing to excellent castability and low shrinkage, attaining the most attention in the laser-based approach. Related studies with these alloys along with precipitation hardening and heat treatment processing were discussed. The Pure Mg, Mg-Al alloy, Mg-RE alloy, and Mg-Zn alloy along with the mechanical characteristics, electrochemical durability, and biocompatibility of Mg-based material have been elaborated in the work-study. The review article also summarizes the processing parameters of the additive manufacturing powder-based approach relating to different Mg-based alloys. For future aspects, the optimization of processing parameters, composition of the alloy, and quality of powder material used will significantly improve the ductility of additively manufactured Mg alloy by the LPBF approach. Other than that, the recycling of Mg-alloy powder hasn’t been investigated yet. Meanwhile, the post-processing approach, including a homogeneous coating on the porous scaffolds, will mark the suitability in terms of future advancements in Mg and Al-based alloys.
Advances in analysis, quantification and modelling of N2O emission in SBRs under various DO set points
- M S Shourjeh
- Mohammad Javad Mehrani
- Przemysław Kowal
- Bartosz Szeląg
- Jakub Drewnowski
2022 Pełny tekst Journal of Physics : Conference Series
Nitrous oxide (N2O), considered a major greenhouse gas (GHG) in wastewater treatment plants (WWTPs), is produced during both nitrification and denitrification processes; hence, it needs to be controlled by internal and external strategies. Various factors, such as DO, temperature, and pH, could be incorporated into the mitigation of emissions in WWTPs. In this research, potential operational strategies were investigated in order to find the optimal range for DO and temperature for controlling the N2O production during the nitrification process. In parallel, the activity of nitrite oxidizing bacteria (NOB) could also be limited under optimal conditions to make the process more cost-effective and energy-saving. In this regard, under a lab-scale environment, DO = 0.7 mg/l was detected as the optimal range for inhibiting NOB activity and maintaining AOB activity. Moreover, the importance of developing mathematical modelling methods has gained significant attention in order to better understand the possibility of minimizing GHG in WWTPs. In this study, advanced mathematical modelling methods were used for simulating the kinetics of the nitrification process to determine the interaction among different operating factors compared to nitrification rates.
Advances in Modelling and Analysis of Strength of Corroded Ship Structures
- Krzysztof Wołoszyk
- Yordan Garbatov
2022 Pełny tekst Journal of Marine Science and Engineering
The present study reviews the recent advances in modelling and analyses the strength of corroded ship structures. Firstly, the time-variant methodologies that consider only the mean structural element thickness loss due to corrosion degradation are identified. Corrosion degradation is regarded as the phenomenon that causes uneven thinning of specimens. This has been captured by various researchers as the loss of mechanical properties of structural steel components. A review of the existing experimental and numerical studies shows significant interest in this field of study. The advances in modelling and analysis of structural behaviours of different ship structural components of larger sizes (including plates, stiffened plates and panels, and entire hull girders) are outlined. Research on the impact of general and pitting corrosion degradation is reviewed separately since the phenomena are different in terms of modelling and analysis. Additionally, recent advances concerning the reliability analysis of corroded ship structural components have also been reviewed. Finally, the general conclusions are drawn and future research topics are outlined.
Adversarial attack algorithm for traffic sign recognition
- Juan Wang
- Lei Shi
- Yang Zhao
- Haoxi Zhang
- Edward Szczerbicki
2022 MULTIMEDIA TOOLS AND APPLICATIONS
Deep learning suffers from the threat of adversarial attacks, and its defense methods have become a research hotspot. In all applications of deep learning, intelligent driving is an important and promising one, facing serious threat of adversarial attack in the meanwhile. To address the adversarial attack, this paper takes the traffic sign recognition as a typical object, for it is the core function of intelligent driving. Considering that the black box attack does not need to know the internal characteristics of the model, it can have more practical value. However, the existing black box attack algorithm has high visit time and low efficiency in attacking sample generation. In this regard, the SimBA algorithm with high efficiency is selected and improved according to the characteristics of traffic signs, named the L-SimBA algorithm. According to the graphic characteristics of traffic signs that are already known, L-SimBA algorithm limits the search subspace consciously and specifies the set of search directions, and that is the core idea of it. By this way, L-SimBA algorithm can generate adversarial samples faster. Experimental comparison shows that in the field of traffic sign recognition, L-SimBA algorithm is better than SimBA algorithm. On the premise of obtaining similar quality adversarial attack samples, the success rate of adversarial measures gets higher, and the number of model visits reduces considerably, thus the attack efficiency of the algorithm improves greatly
Affect aware video games
- Mariusz Szwoch
2022
In this chapter a problem of affect aware video games is described, including such issue as: emotional model of the player, design, development and UX testing of affect-aware video games, multimodal emotion recognition and a featured review of affect-aware video games.
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.