2019 - Repozytorium publikacji - Politechnika Gdańska

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Heat recovery from the hybrid photovoltaic tile – experimental studies with the solar light simulator
- Jan Wajs
- Aleksandra Gołąbek
- Roksana Bochniak
- Dariusz Mikielewicz
2019
Considering the current development of micro-cogeneration energy sources, supported by the national prosumer policy and the act on the renewable energy sources, there is a great demand for the effective solar technologies. In this area, the photovoltaic cells with a combined conversion of the solar radiation energy into the electrical and thermal energy (PV/T cells) seem to be attractive. They are already widely available and treated as the classical solutions. On the other hand, the photocells forming the autonomous roof coverings (the photovoltaic tiles) are still kind of a novelty. In addition to the benefits of electricity generation in PV modules, the heat recovery from them could partially cover the heat demand in the residential or industrial buildings. The paper is dedicated to the hybrid solar systems (PV/T). The greatest attention was devoted to the analysis of heat recovery from the photovoltaic panel and an impact of this process on the efficiency of electricity generation. It is worth to emphasize that one of the very few models of the photovoltaic roof tiles available on the market has been tested. Experimental investigations were carried out on a dedicated experimental stand, equipped with a solar light simulator, designed for the needs of this research.
Heat transfer and pressure drop characteristics of the silicone-based plate heat exchanger
- Tomasz Muszyński
- Rafał Andrzejczyk
- Il Wong Park
- Carlos Alberto Dorao
2019 Pełny tekst Archives of Thermodynamics
The paper presents an experimental investigation of a silicone based heat exchanger, with passive heat transfer intensification by means of surface enhancement. The main objective of this paper was to experimentally investigate the performance of a heat exchanger module with the enhanced surface. Heat transfer in the test section has been examined and described with precise measurements of thermal and flow conditions. Reported tests were conducted under steady-state conditions for single-phase liquid cooling. Proposed surface modification increases heat flux by over 60%. Gathered data presented, along with analytical solutions and numerical simulation allow the rational design of heat transfer devices.
Heat transfer intensification by jet impingement – numerical analysis using RANS approach
- Tomasz Kura
- Elżbieta Fornalik-Wajs
- Jan Wajs
- Sasa Kenjeres
2019 Pełny tekst E3S Web of Conferences
Jet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically complex. Therefore the numerical analysis is necessary to understand the phenomena, especially in the range of turbulent flow. The well-known and accurate method is Reynolds Averaged Navier-Stokes (RANS) approach. However, depending on the applied turbulence model, various results can be obtained. The reason is that the jet impingement strongly depends on the complex boundary layer effects and their resolving is still challenging for RANS models and until now it is their weakest point. In the paper, the hydrodynamic and thermal, numerical results of jet impingement are presented, depending on selected RANS based models. The aim was to indicate their ability to anticipate the turbulence parameters.
Heavy Duty Vehicle Fuel Consumption Modelling Based on Exploitation Data by Using Artificial Neural Networks
- Oskar Wysocki
- Lipika Deka
- David Elizondo
- Jacek Kropiwnicki
- Jacek Czyżewicz
2019 Pełny tekst
One of the ways to improve the fuel economy of heavy duty trucks is to operate the combustion engine in its most efficient operating points. To do that, a mathematical model of the engine is required, which shows the relations between engine speed, torque and fuel consumption in transient states. In this paper, easy accessible exploitation data collected via CAN bus of the heavy duty truck were used to obtain a model of a diesel engine. Various polynomial regression, K-Nearest Neighbor and Artificial Neural Network models were evaluated, and based on RMSE the most relevant sets of parameters for the given algorithm were selected. Finally, the models were compared by using RMSE and Absolute Relative Error scores for 5 test samples. These represent the whole engine’s operating area. Apart from goodness of fit, the models were analyzed in terms of sensitivity to the size of the training samples. ANN and KNN proved to be accurate algorithms for modeling fuel consumption by using exploitation data. The ANN model was ranked best, as it required less observations to be trained in order to achieve an absolute relative error which was lower than 5%. A conventional method, i.e. polynomial regression, performed significantly worse than either the ANN or the KNN models. The approach presented in this study shows the potential for using easy accessible exploitation data to modeling fuel consumption of heavy duty trucks. This leads to the reduction of fuel consumption having a clear positive impact on the environment.
Heavy duty vehicle fuel consumption modelling using artificial neural networks
- Oskar Wysocki
- David Elizondo
- Lipika Deka
2019 Pełny tekst
In this paper an artificial neural network (ANN) approach to modelling fuel consumption of heavy duty vehicles is presented. The proposed method uses easy accessible data collected via CAN bus of the truck. As a benchmark a conventional method, which is based on polynomial regression model, is used. The fuel consumption is measured in two different tests, performed by using a unique test bench to apply the load to the engine. Firstly, a transient state test was performed, in order to evaluate the polynomial regression and 25 ANN models with different parameters. Based on the results, the best ANN model was chosen. Then, validation test was conducted using real duty cycle loads for model comparison. The neural network model outperformed the conventional method and represents fuel consumption of the engine operating in transient states significantly better. The presented method can be applied in order to reduce fuel consumption in utility vehicles delivering accurate fuel economy model of truck engines, in particular in low engine speed and torque range.
Heavy Metals in Sediments of Urban Streams: Contamination and Health Risk Assessment of Influencing Factors
- Ewa Wojciechowska
- Nicole Nawrot
- Jolanta Walkusz-miotk
- Karolina Matej-Łukowicz
- Ksenia Pazdro
2019 Pełny tekst Sustainability
Sediments of two urban streams in northern Poland outflowing to the Baltic Sea were assessed to explain the spatial variation in relation to urbanization level of the catchment, the role of retention tanks (RTs) and identification of pollution level. During the 3 month period of investigation sediment samples were collected from the inflow (IN) and outflow (OUT) of six RTs located on streams for flood protection. Six heavy metals (HMs) were investigated: Cu, Pb, Zn, Cd, Ni, Cr. The assessment of four geochemical enrichment indices used to quantify contamination of HMs in the sediments at IN and OUT samples was carried out. Contamination factor (CF), pollution load index (PLI), geoaccumulation index (Igeo) and potential ecological risk (RI) were calculated and the indices usefulness was assessed. Also, the hazard quotient (HQ) was calculated to assess health risk associated with dredging works. In sediments from RTs where paved surfaces constituted more than 70% of the catchment the HMs concentrations were from one to three times higher for Ni and from two to 143 times higher for Cu in comparison to soft catchment results. The extremely high Cu concentration (1114 mg/kg d.w.) found in sediments at RT Orłowska IN was most likely associated with large area of roofs covered with copper sheet. Calculation of CF, PLI, Igeo, RI, HQ indicators allows for a complex and multi-dimensional assessment of sediment status. Among these, CF and PLI classified the analyzed sediments as most polluted. Basing on the sedimentary HMs concentrations the health risk level via dermal exposure pathway was assessed as low.
Heterogeneous oxidation of highly boron-doped diamond electrodes and its influence on the surface distribution of electrochemical activity
- Jacek Ryl
- Łukasz Burczyk
- Artur Zieliński
- Mateusz Ficek
- Artur Franczak
- Robert Bogdanowicz
- Kazimierz Darowicki
2019 Pełny tekst ELECTROCHIMICA ACTA
The electrochemical active surface area (EASA) of polycrystalline boron-doped diamond (BDD) electrodes is heterogeneous and can be affected by numerous factors. There is a strong need for proper consideration of BDD heterogeneity in order to improve this material's range of application in electrochemistry. Localized changes in surface termination due to the influence of oxidation agent result in increased surface resistance. The observed behavior of this characteristic feature varies among individual grains, depending on their crystallographic orientation. Still, there is not much information about this key factor in terms of its influence on the electrochemical response of BDD. In this study we compared two approaches towards BDD surface oxidation, namely: anodic polarization at potentiostatic and potentiodynamic conditions. The surface impedance measurements via Nanoscale Impedance Microscopy (NIM) allowed the confirmation of diversified propensity for the modification of surface termination in BDD. We showed that the NIM studies provide a deep understanding on the electrical characterization and variation of surface resistance in BDD electrodes. In order to evaluate the actual heterogeneity of electrochemical activity distribution, voltammetry, dynamic electrochemical impedance spectroscopy (DEIS) and scanning electrochemical microscopy (SECM) studies were performed. For each investigated electrode, departure from the Randles-Sevcik equation was observed, with its level depending on the surface heterogeneity and oxidation treatment, justifying the standardization of pre-treatment procedure and development of non-standard model for diffusion transport in proximity of BDD electrode.
High performance super-twisting sliding mode control for a maritime autonomous surface ship (MASS) using ADP-Based adaptive gains and time delay estimation
- Hossein Nejatbakhsh Esfahani
- Rafał Szłapczyński
- Mohammad Hossein Ghaemi
2019 Pełny tekst OCEAN ENGINEERING
This research addresses two kinds of problems related to optimal trajectory tracking of a Maritime Autonomous Surface Ship (MASS): those caused by the time-varying external disturbances including winds, waves and ocean currents as well as those resulting from inherent dynamical uncertainties. As the paper shows, an accurate and robust optimal controller can successfully deal with both issues. An improved Optimal Adaptive Super-Twisting Sliding Mode Control (OAST-SMC) algorithm is proposed here as a robust optimal adaptive strategy. In this strategy, in order to improve performance of the standard super-twisting approach, we apply an Approximate Dynamic Programming (ADP)-based optimal tuning of gains and an underlying concept based on Time Delay Estimation (TDE). An ADP algorithm is implemented using an actor-critic neural network to deal with the curse of dimensionality in Hamilton–Jacobi–Bellman (HJB) equation. The critical role of TDE part in this algorithm is estimating the impact of disturbances and uncertainties on the MASS model. The results have shown that OAST-TDE significantly outperforms the ST-TDE and AST-TDE algorithm in terms of the optimal control efforts. Also, compared with a Nonlinear Model Predictive Control (NMPC), proposed controller meets the optimal control efforts and accurate tracking concurrently.
High Performance Tubular Heat Exchanger with Minijet Heat Transfer Enhancement
- Jan Wajs
- Dariusz Mikielewicz
- Elżbieta Fornalik-Wajs
- Michał Bajor
2019 Pełny tekst HEAT TRANSFER ENGINEERING
In the paper, the original cylindrical heat exchanger with minijets (MJHE) was introduced. The systematic experimental analysis of the prototype heat exchanger was described with special attention paid to such parameters as the heat transfer effectiveness, heat transfer rates, overall heat transfer coefficients, and pressure drop. The heat transfer coefficients were determined based on Wilson plot method, the most suitable approach for heat transfer coefficient determination in exchangers of complex geometry. The thermal-hydraulic characteristics of the in-house manufactured prototype of MJHE in water–water and gas–water configuration are also presented. The experimental results were compared with the predictions from well-known correlations found in the published research papers dedicated to the free-surface and submerged types of jets.
High temperature oxidation behavior of SUS430 SOFC interconnects with Mn-Co spinel coating in air
- Chuan Jia
- Yuhao Wang
- Sebastian Molin
- Yongliang Zhang
- Ming Chen
- Minfang Han
2019 JOURNAL OF ALLOYS AND COMPOUNDS
In this study, SUS430 alloy is evaluated for its high temperature corrosion properties as a possible material for interconnects of solid oxide fuel cells (SOFCs). Samples are coated with Mn-Co by commercial physical vapor deposition (PVD) process and oxidized in air for 1250 h at 800 °C. A dense cubic Mn-Co-Fe spinel layer is formed on the surface, showing great effect on corrosion reduction compared with the samples without coating. A corrosion rate constant of 1.22 × 10−14 g2 cm−4 s−1 is presented in this study for the coated samples, with an area specific resistance (ASR) of around 31 mΩ cm2. After the experiment, microstructures of the samples are analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), which shows that the SUS430 alloy with Mn-Co coating can be considered as one of the low-cost material for the interconnects of SOFCs with good performance.
High-efficiency mini and micro heat exchangers for dispersed power generation
- Jan Wajs
- Dariusz Mikielewicz
2019
Taking into account the dispersed systems technologies and their development, the ORC systems seem to be promising technology amongst various micro-CHP domestic units (electrical power production below 10 kWe), however practical realization of the ORC cycle in a micro-scale is technically challenging. The system consists in devices such as the vapour generation unit (boiler), expansion device and heat exchangers. Each of them should be of high performance so that the system as a whole could work efficiently. This is the reason why novel constructions of heat exchangers or heat transfer enhancement mechanisms are looked for in relation to the evaporator, condenser or regenerator. In the present paper the own construction of compact heat exchangers (plate-type and cylindrical constructions) with microjets and with minichanels are proposed. They were designed on the basis of several years of experiences, for the needs of domestic ORC system and other dispersed energy generation technologies. The features of mentioned above heat exchangers are discussed together with the flow and thermal characteristics of their prototypes. As a summary, the experimental studies of the authors domestic ORC unit equipped with prototype minichannel heat exchangers are also presented.
Highlights from RNDM 2018 – 10th Anniversary Workshop on Resilient Networks Design and Modeling
- Jacek Rak
- Poul Heegaard
- Bjarne Helvik
2019 IEEE COMMUNICATIONS MAGAZINE
Artykuł prezentujący relację z workshopu RNDM 2018
Highly effective asphaltene-derived adsorbents for gas phase removal of volatile organic compounds
- Maksymilian Plata-Gryl
- Malwina Momotko
- Sławomir Makowiec
- Grzegorz Boczkaj
2019 Pełny tekst SEPARATION AND PURIFICATION TECHNOLOGY
A novel nitrated asphaltene-derived adsorbent (Asf-Nitro) was prepared using facile isolation and modification procedures. The successful modification was confirmed by Fourier-transform infrared spectroscopy (FTIR). The nitrated adsorbent was evaluated in terms of dispersive and specific interactions, Lewis acid-base properties and adsorption isotherms by means of inverse gas chromatography (IGC). Nitration was found to be extremely effective in enhancing adsorption properties of asphaltenes towards variety of chemical compounds. Asf-Nitro adsorbent exhibits superior dispersive interactions (197.50 ± 1.12 mJ m-2 at 423 K), as compared to unmodified asphaltenes, which are comparable with activated carbons, zeolites or alumina. Examination of the specific interactions revealed a shift from basic to acidic character of the surface, what will be beneficial for adsorption of alkaline gases. Additionally, adsorption isotherms revealed that developed surface properties of the Asf-Nitro results in more than doubled monolayer adsorption capacity. Obtained results demonstrates the applicability of the asphaltene-derived materials in adsorption processes as highly effective and low cost adsorbents. This studies revealed a highly effective adsorption of environmentally important VOCs, e.g. n-butanol (odorous compound), trichloromethane (chlorinated hydrocarbon) and benzene (carcinogenic).
High-temperature heat pumps – potential technology for heat recovery and production of process heat
- Dariusz Mikielewicz
- Jan Wajs
2019
In the paper, the high temperature vapour compressor based heat pump with a selection of working fluids, both perspective and ecological ones, is considered. Such system is not yet commercially available on the market and in author’s opinion it has significant potential for various applications. In the presented analysis it was assumed that the heat source has a temperature of 50oC and the temperature lift is 60, 80 and 100K respectively. Such temperature lift is a requirement for perspective applications. On the basis of obtained results the fluid working temperatures, heat rates, coefficient of performance of proposed solution as well as second law analysis have been determined. They confirm the potential for implementation in high temperature heat pumps in energy engineering area. Especially ethanol as working fluid seems to outperform other fluids.
High-temperature kinetics study of 430L steel powder oxidized in air at 600–850 °C
- Jakub Karczewski
- Tomasz Brylewski
- Tadeusz Miruszewski
- K. H. Andersen
- Piotr Jasiński
- Sebastian Molin
2019 CORROSION SCIENCE
The 430L stainless steel powder with a mean particle size of 95 μm was studied to determine its high-temperature oxidation properties. Continuous thermogravimetric measurements were carried out for 100 h in air at temperatures in the range of 600–850 °C. Even though a considerable amount of Cr (up to ˜5 wt.% Cr) inside the grains was depleted – especially inside small grains – no breakaway oxidation was observed. This indicates that both the remaining Cr and the formed chromia scale remained protective with regard to the metallic core until the Cr concentration reached very low levels.
High-temperature oxidation of the Crofer 22 H ferritic steel with Mn1.45Co1.45Fe0.1O4 and Mn1.5Co1.5O4 spinel coatings under thermal cycling conditions and its properties
- M Bednarz
- Sebastian Molin
- Michał Bobruk
- M Stygar
- E Długoń
- M Sitarz
- Tomasz Brylewski
2019 MATERIALS CHEMISTRY AND PHYSICS
The aim of the presented study was to deposit protective-conducting Mn1.45Co1.45Fe0.1O4 and Mn1.5Co1.5O4 spinel coatings on the Crofer 22 H ferritic steel by means of electrophoresis and to evaluate their physicochemical properties after high-temperature oxidation under thermal cycling conditions. When the Crofer 22 H steel – whether uncoated or coated with the two spinels – was oxidized in 48-h cycles involving a temperature of either 750 or 800 °C, its oxidation kinetics approximately obeyed the parabolic rate law. The oxidation rate observed for uncoated steel was higher than that for the studied coating/steel systems. The Fe-doped spinel coating material improved the oxidation resistance of steel to a higher degree than the undoped spinel coating. The obtained bulk spinels exhibited a regular phase composition and high electrical conductivity, while the Mn1.45Co1.45Fe0.1O4 and Mn1.5Co1.5O4 coatings were dual-phase, compact, and exhibited good adhesion to the metallic substrate. The area-specific resistance values measured for the steel/coating systems indicate that the coatings significantly improve the electrical properties of the studied ferritic steel, especially at 800 °C. The conducted research confirmed the suitability of the Mn1.45Co1.45Fe0.1O4 and Mn1.5Co1.5O4 spinels as coatings on the Crofer 22 H ferritic steel to be applied in the production of interconnects used in intermediate-temperature SOFCs.
High-temperature properties of titanium-substituted yttrium niobate
- Aleksandra Mielewczyk-Gryń
- Piotr Winiarz
- Sebastian Wachowski
- Maria Gazda
2019 JOURNAL OF MATERIALS RESEARCH
he defect fluorite titanium-doped yttrium niobate samples Y3Nb1−xTixO7−δ have been synthesized and investigated by the means of high-temperature X-ray diffraction, dilatometry, and thermogravimetry. Thermal expansion coefficients (TECs) as well as chemical expansion coefficients for material with 5, 10, and 15 mol% of titanium were determined. All investigated samples exhibit chemical contraction caused by Ti doping. The values of TECs obtained by two different methods show similar results, which suggests the isotropy of the polycrystalline ceramic. Thermogravimetric studies have shown that all of the compositions exhibit a mass increase upon being exposed to a humid air atmosphere. The total proton concentration calculated on the basis of these results was in the range of 0.1 mol%. Moreover, titanium content influences chemical expansion coefficient, water uptake, and protonic defects concentration, whereas it does not significantly affect the values of TECs
Historia i materialne relikty fortyfikacji Westerplatte sprzed 1920 r.
- Arkadiusz Woźniakowski
2019
Z uwagi na swoje położenie Westerplatte od momentu uformowania się wyspy, a następnie półwyspu, miało kluczowe znaczenie dla obrony wejścia do portu w Gdańsku. Pierwsze znane nowożytne fortyfikacje na terenie Westerplatte to oszańcowany obóz warowny wojsk pruskich z końca XVII w., ale najintensywniejsza rozbudowa umocnień nastąpiła od połowy XIX w., kiedy położono większy nacisk na zabezpieczenie ujścia Wisły. Od lat osiemdziesiątych XIX w. w Gdańsku rozbudowywano już tylko fortyfikacje nadbrzeżne, z których wiele znalazło się na Westerplatte. Przechodziły one wiele przemian związanych przede wszystkim z rozwojem uzbrojenia i taktyki, ale także naturalną działalnością morza, rozwojem przemysłu portowego i zmianami geopolitycznymi. Celem artykułu jest prześledzenie rozwoju i zmian w układzie przestrzennym fortyfikacji Westerplatte do momentu utworzenia Wolnego Miasta Gdańska oraz identyfikacja zachowanych reliktów w świetle najnowszych badań i źródeł kartograficznych. Jest to przyczynek do badań nad mniej znanym rozdziałem w militarnej historii tego miejsca, jeszcze przed ustanowieniem Wojskowej Składnicy Tranzytowej.
History and Milestones of Green Analytical Chemistry
- Justyna Płotka-Wasylka
- Magdalena Fabjanowicz
- Kaja Kalinowska
- Jacek Namieśnik
2019
Due to the increased environmental consciousness, Green Analytical Chemistry (GAC) is an important concept steadily gaining popularity, as its implementation facilitates the decrease the detrimental effect analytical chemistry methodologies may have on the environment. In this chapter, a brief overview of the history of Green Analytical Chemistry (GAC) and its milestones was given. Emphasis has been put on the beginnings of green chemistry awareness and on the possibilities of increasing and evaluating the greeness of both currently used and designed analytical chemistry methodologies. In addition, the prospects of implementation of 12 principles of Green Analytical Chemistry have been briefly described.
Home Sweet Home. Connecting the dots for healthy evening residential illumination
- Karolina Zielińska-Dąbkowska
2019 Pełny tekst ARC Lighting In Architecture
During the twentieth century, lighting designers would commonly use incandescent light sources for residential homes as they provided a visual comfort, with high quality colour rendering properties, along with relaxing ambient atmosphere. Unfortunately, it’s now difficult to buy incandescent light sources because they have been banned in many countries (https://bit.ly/2GwN2Wv). This article addresses some of the challenges in regards to health, brought about by the changeover to new LEDs and other related technologies, and tries to offer some context on how to keep up with these rapid transformations. While we know it’s necessary to limit blue-rich light at night (as it prevents melatonin production and impaires nocturnal sleep), and that it’s important to maximise exposure to the blue wavelength of light in the morning (to trigger circadian timing, increase alertness), there are other issues that are misunderstood and often ignored. This includes flicker from LEDs and electromagnetic fields (EMFs), which can be produced by smart home lighting technology.