2021 - Publications Repository - Gdańsk University of Technology

Show publications from the year

Publications from the year 2021

Show all

Thermal and technological aspects of double face grinding of C45 carbon steel
- Mariusz Deja
- Linus Lichtschlag
- Eckart Uhlmann
2021 Full text Journal of Manufacturing Processes
In grinding, the contact zone temperature is a decisive factor influencing the achievable surface quality and the grinding tool wear. In contrast to other grinding processes, only few information regarding double face grinding with planetary kinematics when processing steel is known up to date. Since the successive substitution of in-dustrial double-sided lapping processes by double-sided grinding, it has become necessary to the conducted research in order to provide deeper understanding of the process and factors that influence it. To determine the workpiece temperature during grinding of C45 components, silicon temperature sensors were integrated into the workpiece holders and technological investigations were carried out. The influences and interactions of the mean cutting speed, cooling lubricant flow rate and cutting ability of the grinding wheels on the resulting workpiece temperature were analysed. Subsequently, modelling enabled an empirical estimation of the resulting workpiece temperature for processes in the investigated test area. With regard to the design and optimization of processes for machining plane-parallel workpiece surfaces, this model is a helpful tool for avoiding thermally induced workpiece damage and reduction of tool wear. Furthermore, the method can be used to conduct further ex-aminations on the grinding process and to reduce the amount of cooling lubricant used, to improve life cycle assessment.
Thermal Buckling Analysis of Circular Bilayer Graphene sheets Resting on an Elastic Matrix Based on Nonlocal Continuum Mechanics
- M. Ahmad Pour
- M. E. Golmakani
- Mohammad Malikan
2021 Full text Journal of Applied and Computational Mechanics
In this article, the thermal buckling behavior of orthotropic circular bilayer graphene sheets embedded in the Winkler–Pasternak elastic medium is scrutinized. Using the nonlocal elasticity theory, the bilayer graphene sheets are modeled as a nonlocal double–layered plate that contains small scale effects and van der Waals (vdW) interaction forces. The vdW interaction forces between the layers are simulated as a set of linear springs using the Lennard–Jones potential model. Using the principle of virtual work, the set of equilibrium equations are obtained based on the first-order shear deformation theory (FSDT) and nonlocal differential constitutive relation of Eringen. Differential quadrature method (DQM) is employed to solve the governing equations for simply-supported and clamped boundary conditions. Finally, the effects of the small scale parameter, vdW forces, aspect ratio, elastic foundation, and boundary conditions are considered in detail.
Thermal utilization of meat-and-bone meal using the rotary kiln pyrolyzer and the fluidized bed boiler – The performance of pilot-scale installation
- Marcin Kantorek
- Krzysztof Jesionek
- Sylwia Polesek-Karczewska
- Paweł Ziółkowski
- Michał Stajnke
- Janusz Badur
2021 Full text RENEWABLE ENERGY
Thermal utilization of meat-and-bone meal (MBM) is subject to stringent regulations that are meant to provide elimination of any potential pathogens. Incineration as well as other possible routes for thermal conversion of MBM are still at the research state. The universal technology was developed that allows to combust various types of waste organic materials, including animal waste, municipal solid waste and sludge, mixed at any ratio with different types of biomass. It provides the possibility to utilize the wasteand- biomass fuel blends of up to 90%wt of moisture content, while maintaining the allowable pollutant emissions and soil contamination. This regards mainly NOx, SO2, HCl and VOC. Contrary to the typical large scale grate boilers used for waste burning, the developed operating pilot-scale plant with a capacity of 12 MW offers the complete combustion of MBM, resulting in a flue gas which is proved to be free of flammable gaseous components and sooty particles in slag and fly ash. The thermal decomposition and combustion of waste using this technology ensures thermal conversion of chemical energy contained in waste and biomass. The efficiency of the prototype installation varied between 84.8 and 88.4% depending on the facility load.
Thermodynamic Analysis of Negative CO2 Emission Power Plant Using Aspen Plus, Aspen Hysys, and Ebsilon Software
- Paweł Ziółkowski
- Paweł Madejski
- Milad Amiri
- Tomasz Kuś
- Kamil Stasiak
- Navaneethan Subramanian
- Halina Pawlak-kruczek
- Janusz Badur
- Łukasz Niedźwiecki
- Dariusz Mikielewicz
2021 Full text ENERGIES
Abstract: The article presents results of thermodynamic analysis using a zero-dimensional mathematical models of a negative CO2 emission power plant. The developed cycle of a negative CO2 emission power plant allows the production of electricity using gasified sewage sludge as a main fuel. The negative emission can be achieved by the use this type of fuel which is already a “zeroemissive” energy source. Together with carbon capture installation, there is a possibility to decrease CO2 emission below the “zero” level. Developed models of a novel gas cycle which use selected codes allow the prediction of basic parameters of thermodynamic cycles such as output power, efficiency, combustion composition, exhaust temperature, etc. The paper presents results of thermodynamic analysis of two novel cycles, called PDF0 and PFD1, by using different thermodynamic codes. A comparison of results obtained by three different codes offered the chance to verify results because the experimental data are currently not available. The comparison of predictions between three different software in the literature is something new, according to studies made by authors. For gross efficiency (54.74%, 55.18%, and 52.00%), there is a similar relationship for turbine power output (155.9 kW, 157.19 kW, and 148.16 kW). Additionally, the chemical energy rate of the fuel is taken into account, which ultimately results in higher efficiencies for flue gases with increased steam production. A similar trend is assessed for increased CO2 in the flue gas. The developed precise models are particularly important for a carbon capture and storage (CCS) energy system, where relatively new devices mutually cooperate and their thermodynamic parameters affect those devices. Proposed software employs extended a gas–steam turbine cycle to determine the effect of cycle into environment. First of all, it should be stated that there is a slight influence of the software used on the results obtained, but the basic tendencies are the same, which makes it possible to analyze various types of thermodynamic cycles. Secondly, the possibility of a negative CO2 emission power plant and the positive environmental impact of the proposed solution has been demonstrated, which is also a novelty in the area of thermodynamic cycles
Thermodynamic Studies of Interactions between Sertraline Hydrochloride and Randomly Methylated β-Cyclodextrin Molecules Supported by Circular Dichroism Spectroscopy and Molecular Docking Results
- Sylwia Belica-Pacha
- Mateusz Daśko
- Vyacheslav Buko
- Ilya Zavodnik
- Katarzyna Miłowska
- Maria Bryszewska
2021 Full text INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
The interaction between sertraline hydrochloride (SRT) and randomly methylated β-cyclodextrin (RM β CD) molecules have been investigated at 298.15 K under atmospheric pressure. The method used—Isothermal Titration Calorimetry (ITC) enabled to determine values of the thermodynamic functions like the enthalpy (DH), the entropy (DS) and the Gibbs free energy (DG) of binding for the examined system. Moreover, the stoichiometry coefficient of binding (n) and binding/association constant (K) value have been calculated from the experimental results. The obtained outcome was compared with the data from the literature for other non-ionic βCD derivatives interacting with SRT and the enthalpy-entropy compensation were observed and interpreted. Furthermore, the connection of RM β CD with SRT was characterized by circular dichroism spectroscopy (CD) and complexes of βCD derivatives with SRT were characterized through the computational studies with the use of molecular docking (MD).
THERMOMECHANICAL PERFORMANCE OF FLEXIBLE POLYURETHANE FOAMS AS A FUNCTION OF THE ISOCYANATE INDEX
- Aleksander Hejna
- Paulina Kosmela
- Adam Olszewski
- Łukasz Zedler
- Krzysztof Formela
2021
Polyurethane foams are very versatile materials applied in different branches of industry. Their popularity is attributed, among others, to the flexibility in engineering their mechanical performance by the adjustment of their formulations. One of the most crucial factors is the isocyanate index, determining the ratio between the free hydroxyl and isocyanate groups present in the polyurethane system. By the change of this ratio, the mechanical properties of foams may be adjusted. In the presented paper, we presented the isocyanate index's influence during foams’ preparation on their thermomechanical performance analyzed by the dynamic mechanical analysis.
Thermo-Mechanical Simulation of Underwater Friction Stir Welding of Low Carbon Steel
- Shabbir Memon
- Jacek Tomków
- Hesamoddin Aghajani Derazkola
2021 Full text Materials
This article investigates the flow of materials and weld formation during underwater friction stir welding (UFSW) of low carbon steel. A thermo-mechanical model is used to understand the relation between frictional heat phenomena during the welding and weld properties. To better understand the effects of the water environment, the simulation and experimental results were compared with the sample prepared by the traditional friction stir welding (FSW) method. Simulation results from surface heat diffusion indicate a smaller preheated area in front of the FSW tool declined the total generated heat in the UFSWed case compared to the FSWed sample. The simulation results revealed that the strain rate of steel in the stir zone (SZ) of the FSWed joint is higher than in the UFSWed case. The microstructure of the welded sample shows that SZ’s microstructure at the UFSWed case is more refined than the FSWed case due to the higher cooling rate of the water environment. Due to obtained results, the maximum temperatures of FSWed and UFSWed cases were 1228 °C and 1008 °C. Meanwhile, the simulation results show 1200 °C and 970 °C for conventional and underwater FSW samples, respectively. The maximum material velocity in SZ predicted 0.40 m/s and 0.32 m/s for FSW and underwater FSWed samples. The better condition in the UFSW case caused the ultimate tensile strength of welded sample to increase ~20% compared to the FSW joint.
Thermo-oxidative exfoliation of carbon black from ground tire rubber as potential reinforcement in green tires
- Adeel Hassan
- Zhen Zhang
- Krzysztof Formela
- Shifeng Wang
2021 COMPOSITES SCIENCE AND TECHNOLOGY
Considering the balance between rapidly growing global tire demand and scarcity of natural resources, recycling and reclaiming techniques of tire rubber have become the state of the art. Herein, we set out to implement a self-designed thermo-oxidative reactor for the exfoliation of carbon black (CB) from ground tire rubber, which is efficiently functioned under a thermo-oxidative reclaiming condition without any additive. The exfoliation of CB from rubber vulcanizate was realized by scission of main chain, and of cross-linked network. The degree of scission was discussed through gel permeation chromatography and using Horikx theory. Sol fraction tremendously increased to 66.0% after thermo-oxidative reclamation at 200 °C for 20 min. Thermo-oxidative scission underwent through the oxidative cleavage of main chain, and of sulfur cross-links, proved by Fourier transform infrared spectroscopy. The ultrafine exfoliation of CB from rubber proved by field emission scanning electron microscopy. The exfoliation was further improved by two roll milling. Exfoliated rubber was incorporated within tire rubber composites as a reinforcing material due to the core-shell structured CB, which was observed with increased effects to the rubber composites. This work presents a potential contribution to the industrial recycling for future applications and to control the pollution of waste tires.
Thermoplastic starch nanocomposites using cellulose-rich Chrysopogon zizanioides nanofibers
- Midhun Dominic C.D.
- Derval dos Santos Rosa
- Paulo Henrique Camani
- Athira S Kumar
- Neenu K.v.
- P.M. Sabura Begum
- Divya Dinakaran
- Effina John
- Donna Baby
- Meenu Mariya Thomas
- Jaison M. Joy
- Jyotishkumar Parameswaranpillai
- Mohammad Saeb
2021 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
Green thermoplastic starch (TPS) nanocomposite films aided by cellulose nanofibers (CNFs) from Chrysopogon zizanioides roots were developed and characterized. When compared to other lignocellulosic fibers, Chrysopogon zizanioides roots revealed exceptionally high cellulose content (~48%). CNFs were separated using an environmentally friendly acid isolation technique that included three stages: (i) alkali treatment; (ii) bleaching; and (iii) mild acid hydrolysis using oxalic acid in an autoclave. Following that, green nanocomposite films were made from potato starch using the solution casting process, by which we used glycerol (30 wt%) to make thermoplastic starch. Then, cellulose nanofibers in different concentrations (0, 1, 2, 3, 4 wt%) were added to the thermoplastic starch matrix. The isolated CNFs had diameters in the range of 17–27 nm. Besides, these nanostructures presented a very high crystallinity index (~65%), thereby enhanced the thermal stability. TPS/CNF green nanocomposites containing 3 wt% CNFs had exceptional tensile strength (~161%), tensile modulus (~167%), thermal stability, and crystallinity. As a result, nanocomposite films made of starch and cellulose nanofibers (3 wt%) extracted from Chrysopogon zizanioides roots would be alternatives for sustainable packaging. It can be concluded that Chrysopogon zizanioides roots have high potential for polymer industry.
Three Principles for Healthy Living with Light and Lighting
- Karolina Zielińska-Dąbkowska
- Ruth Kelly Waskett
2021 Full text ARC Lighting In Architecture
The lockdown measures applied to cities and towns during the worldwide Covid-19 pandemic have had a widespread impact on people’s lives. Some have found themselves confined to their homes, with limited social contact and a reduced quality of life. Others have found that the lockdown improved their wellbeing, as more time was spent outside, instead of commuting and working in an office building, plus the benefits of spending increased quality time with loved ones. The pandemic raised public consciousness about the need to take control of our own wellbeing and health: in particular, to take greater care of immunity. There was also concern about the consequences of extended time spent in indoor spaces, which can create mental fatigue that can manifest itself in a number of ways, including reduced productivity, lack of concentration and in some cases, depression. Many people soon realised the simple things in life that had previously been taken for granted, such as access to daylight and contact with nature, play a vital role in mental health and wellbeing.
Three-dimensional modeling and automatic analysis of the human nasal cavity and paranasal sinuses using the computational fluid dynamics method
- Dmitry Tretiakow
- Krzysztof Tesch
- Jarosław Meyer-Szary
- Karolina Markiet
- Andrzej Skorek
2021 Full text EUROPEAN ARCHIVES OF OTO-RHINO-LARYNGOLOGY
Purpose The goal of this study was to develop a complete workflow allowing for conducting computational fluid dynam- ics (CFD) simulation of airflow through the upper airways based on computed tomography (CT) and cone-beam computed tomography (CBCT) studies of individual adult patients. Methods This study is based on CT images of 16 patients. Image processing and model generation of the human nasal cavity and paranasal sinuses were performed using open-source and freeware software. 3-D Slicer was used primarily for segmentation and new surface model generation. Further processing was done using Autodesk ® Meshmixer TM. The gov- erning equations are discretized by means of the finite volume method. Subsequently, the corresponding algebraic equation systems were solved by OpenFOAM software. Results We described the protocol for the preparation of a 3-D model of the nasal cavity and paranasal sinuses and high- lighted several problems that the future researcher may encounter. The CFD results were presented based on examples of 3-D models of the patient 1 (norm) and patient 2 (pathological changes). Conclusion The short training time for new user without a prior experience in image segmentation and 3-D mesh editing is an important advantage of this type of research. Both CBCT and CT are useful for model building. However, CBCT may have limitations. The Q criterion in CFD illustrates the considerable complication of the nasal flow and allows for direct evaluation and quantitative comparison of various flows and can be used for the assessment of nasal airflow.
Three-Dimensional Printing of Bone Models
- Angela Andrzejewska
2021
The trabecular bone occurs, for example, in the femoral heads. Understanding the phenomenon of bone tissue degeneration can be the basis for the possibility of looking for alternative methods of surgical treatment of bone loss. The paper presents the results of the trabecular bone model, which was produced in additive manufacturing method with fused filament fabrication technology. The verification of the mechanical behavior of the trabecular bone model was based on the analysis of uniaxial compression test. The model was also conditioned under degradation process to determine the influence of the physiological fluid environment due to changes in the mechanical response of the modeled bone. The obtained results showed that the mechanical strength of the proposed spongy bone model and the method of its production allow to obtain strength values close to the natural spongy bone. In addition, the strength did not change during the 4-week degradation process.
THREE-LEVEL F-TYPE INVERTER
- Charles Odeh
- Arkadiusz Lewicki
- Marcin Morawiec
- Dmytro Kondratenko
2021 IEEE TRANSACTIONS ON POWER ELECTRONICS
Given the recent available IGBT switch modules up to 6.5 kV, 1200 A rating, the prospect of the diode-free variant topology of the three-level neutral-point-clamped (3-level, T-type) inverter in certain medium voltage applications is bright; due to its small part count and low conduction losses compared to the diode-clamped NPC inverter. However, within this voltage range, the input dc voltage rating of 50% of the switches per inverter phase-leg still poses limitations to the deployment of 3-level T-type inverter. In view of these limitations, a reconfigured four-switch per phase-leg power circuit for 3-level inverter (F-type) is presented in this paper. The common node of the bidirectional switch in T-type inverter is explored to have only one power switch rated at input dc voltage and 3 switches rated at half the input dc voltage, per inverter-leg. This reduced voltage stress has inverter cost and loss implications. The performances and competitiveness of the three-level, F-type inverter are analyzed in detail and demonstrated with a hardware prototype. Results reveal that it has the potentials of being considered a real alternative to 3-level, T-type inverters for certain low- and medium-voltage applications.
Time-current tripping characteristics of RCDs for sinusoidal testing current
- Stanisław Czapp
2021
Low-voltage electrical installations are verified initially – before being put into operation, as well as periodically – during their utilization. According to the IEC standards, the scope of the verification includes measurements of both the tripping current and the disconnection time of residual current devices (RCDs). Experiences in RCDs testing show that disconnection times of two or more similar RCDs can be quite different. Significant differences in disconnection times are also noticed for the same RCD in the consecutive trials. This paper presents the result of the test of twenty-four RCDs. Their real tripping current, as well as disconnection time, have been verified. Differences in the obtained values of disconnection times are commented, and their possible sources are indicated.
Tin Oxide Encapsulated into Pyrolyzed Chitosan as a Negative Electrode for Lithium Ion Batteries
- Andrzej Nowak
- Maria Gazda
- Marcin Łapiński
- Zuzanna Zarach
- Konrad Trzciński
- Mariusz Szkoda
- Szymon Mania
- Jinjin Li
- Robert Tylingo
2021 Full text Materials
Tin oxide is one of the most promising electrode materials as a negative electrode for lithium-ion batteries due to its higher theoretical specific capacity than graphite. However, it suffers lack of stability due to volume changes and low electrical conductivity while cycling. To overcome these issues, a new composite consisting of SnO2 and carbonaceous matrix was fabricated. Naturally abundant and renewable chitosan was chosen as a carbon source. The electrode material exhibiting 467 mAh g−1 at the current density of 18 mA g−1 and a capacity fade of only 2% after 70 cycles is a potential candidate for graphite replacement. Such good electrochemical performance is due to strong interaction between amine groups from chitosan and surface hydroxyl groups of SnO2 at the preparation stage. However, the charge storage is mainly contributed by a diffusion-controlled process showing that the best results might be obtained for low current rates
To i-vote or not to i-vote: Drivers and barriers to the implementation of internet voting
- Nathan Licht
- David Duenas Cid
- Iuliia Krivonosova
- Robert Krimmer
- David Duenas-Cid
2021 Full text
This paper investigates the drivers and barriers of internet voting and the implications of a global pandemic for the development of the respective technology. In contrast to the expected uptake in the early 2000s of internet voting, the technology is still rather seldomly used in election systems around the world. The paper at hand explores the different forces that drive or impede internet voting adoption from a political, social, legal, organizational, contextual, economic and technological perspective. In an exploratory approach, 18 expert interviews and extensive complementary desk research were conducted. The findings identified 15 general drivers and 15 general barriers for the process of internet voting adoption. The evidence suggests that for a large part, the political features, trust and perception are the most pivotal factors to internet voting development.
Topological, nonreciprocal, and multiresonant slow light beyond the time-bandwidth limit
- Kosmas L. Tsakmakidis
- Konstantinos Baskourelos
- Tomasz Stefański
2021 Full text APPLIED PHYSICS LETTERS
Topologically protected transport has recently emerged as an effective means to address a recurring problem hampering the field of slow light for the past two decades: its keen sensitivity to disorders and structural imperfections. With it, there has been renewed interest in efforts to overcome the delay-time-bandwidth limitation usually characterizing slow-light devices, on occasion thought to be a fundamental limit. What exactly is this limit, and what does it imply? Can it be overcome? If yes, how could topological slow light help, and in what systems? What applications might be expected by overcoming the limit? Our Perspective here attempts addressing these and other related questions while pointing to important new functionalities both for classical and quantum devices that overcoming the limit can enable.
Torque capacity of multidisc wet clutch with reference to friction occurrence on its spline connections
- Marcin Bąk
2021 Full text Scientific Reports
In this article developed mathematical model that includes friction occurrence on spline connections is presented. The work also contains results of experimental research on torque capacity of multidisc wet clutch. These results are expressed as a function of contact pressure for different number of friction surfaces. Due to increased interest in research concerning multidisc wet clutches it is essential to determine impact of friction on fit connections on transmitted torque. Analytical calculations that include both known loss coefficient and assumed lack of friction on fit connections are compared to results of experiments. The paper contains detailed description of test stand and methodology of experiment. As a result of conducted tests it was found that correction coefficients known from literature are highly inaccurate. Measured values of torque indicate that transmitted torque reach significantly higher values. It was also revealed that after slippage appeared, the pressure plate usually moved in the direction of exerted clamping force, but movement in reversed direction also took place for some experiments. While movement corresponding to clamping force reached ca. 0.08 mm, in opposite direction amounted to 0.02 mm. Furthermore, studies presented that lapping of adjacent friction surfaces greatly affects differences between respective results obtained for a specific experiment.
Torque Transmitted by Multi-plate Wet Clutches in Relation to Number of Friction Plates and Their Dimensions
- Marcin Bąk
- Piotr Patrosz
- Paweł Śliwiński
2021
In the paper results of experimental tests on multi-plate wet clutch torque capacity for various diameters and numbers of friction plates are presented. Construction of an apparatus for laboratory tests of wet clutch engagement, drag torque and maximum torque is shown. Methodology of maximum torque capacity experiment and hydraulic circuit diagram, which supplies a motor and an actuator for the experiment are described. Analytically calculated values of torque capacity are compared to results obtained with laboratory tests. Additionally, the article includes FEM analysis, that was used to obtain pressure distribution on every friction surface in relation to force applied to the assembly and to determine differences in these distributions. The analysis has helped to determine a mean radius of sliding interface on each surface and to compare their values to other plates and to result calculated analytically. A diagram is shown in the article, that demonstrates pressure concentration as a function of number of friction surfaces.
Total chromatic sum for trees
- Michał Małafiejski
- Krzysztof Ocetkiewicz
- Ewa Kubicka
- Grzegorz Kubicki
2021
The total chromatic sum of a graph is the minimum sum of colors (natural numbers) taken over all proper colorings of vertices and edges of a graph. We provide infinite families of trees for which the minimum number of colors to achieve the total chromatic sum is equal to the total chromatic number. We construct infinite families of trees for which these numbers are not equal, disproving the conjecture from 2012.