2023 - Repozytorium publikacji - Politechnika Gdańska

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Spatial aspects of urban air quality management: Estimating the impact of micro-scale urban form on pollution dispersion
- Joanna Badach
- Wojciech Wojnowski
- Jacek Gębicki
2023 Pełny tekst COMPUTERS ENVIRONMENT AND URBAN SYSTEMS
Urban planning and design solutions affect urban ventilation conditions, thus mitigating the effects of atmospheric pollution. However, these findings are not being implemented in the planning practice to a sufficient extent, partly due to the lack of specific guidelines. Moreover, many urban air quality monitoring (AQM) sites have low represnentativeness and thus do not provide comprehensive data for effective urban air pollution control with respect to the urban spatial policy. An integrated assessment method based on modelling, simulation, and geospatial data processing tools was used to investigate the impact of micro-scale urban form on the local ventilation conditions and pollution dispersion. The proposed approach combined computational fluid dynamics (CFD) and geographic information system (GIS) tools, and particularly the newly developed Residence Time Index (RTI) - a single CFD-derived parameter quantifying the capabilities of the micro-scale built environment to retain PM10 pollution. Urban segments around monitoring sites in three Polish cities (Gda´nsk, Warsaw, and Pozna´n), characterised by relatively low density and varied urban form typologies, were investigated. The results indicate that in these conditions the following features of the urban form have the strongest correlation with the RTI: plan area density (λP), gross floor area ratio (λGFA), and occlusivity (Oc), making them useful indicators for urban air quality management. On the other hand, PM10 data from the AQM sites are rather poorly linked with urban form indicators, which suggests that in complex urban scenarios a higher spatial resolution of air quality data is required for shaping the spatial policy. The implications from this analysis are useful for the urban planning practice. The developed approach may be also a valuable decision support tool for the assessment of the spatial representativeness of AQM sites.
Spatial Distribution of Eucalyptus Plantation and its Impact on the Depletion of Groundwater Resources of Tehsil Swat Ranizai, District Malakand
- Muhammad Jamal Nasir
- Waqar Akhtar
- Vipin Kumar Oad
2023 Pełny tekst Arabian Journal of Geosciences
Native to the continent of Australia, eucalyptus is a tall, evergreen tree belonging to the Myrtaceae family. Malakand district has the largest eucalyptus plantation in the province, covering an area of 22,071.29 ha. The present study aims to evaluate its impact on the groundwater table (GWT) in three selected union councils (UCs) of the study area, i.e., Agra, Totakan, and Kot. Both primary and secondary data support the study. The data regarding eucalyptus plantations were collected from the Malakand Forest Division. GPS was used to mark the wells’ locations. The current GWT was measured in the field. Rainfall data of the study area and surrounding was acquired from the Regional Meteorological Office Peshawar. A questionnaire survey was conducted to determine the respondents’ opinion of the impact of eucalyptus plantations. The study reveals that though the GWT dropped from 2000 to 2019 in the study area, the decline is more significant in the vicinity of the plantation. The GWT near the plantation in the Agra UC dropped from 39 to 60 ft., 25 to 45 ft. in Totakan, and from 20 to 60 ft. in Kot UC during the study period. The study reveals no significant impact of rainfall on GWT depletion. The respondents appear to be aware of the negative effects of eucalyptus plantations on the GWT, agriculture, and biodiversity. The study concludes that, while considering community interests, there is a critical need for research to investigate and quantify the site-specific effects of eucalyptus on the ecosystem. The study concludes that, while considering community interests, there is a critical need for research to investigate and quantify the site-specific effects of eucalyptus on the ecosystem. The Eucalyptus will be able to continue fending off the rising deforestation and demand for fuel until then.
Spatial Visualization Based on Geodata Fusion Using an Autonomous Unmanned Vessel
- Marta Wlodarczyk-Sielicka
- Dawid Połap
- Katarzyna Prokop
- Karolina Połap
- Andrzej Stateczny
2023 Pełny tekst Remote Sensing
The visualization of riverbeds and surface facilities on the banks is crucial for systems that analyze conditions, safety, and changes in this environment. Hence, in this paper, we propose collecting, and processing data from a variety of sensors—sonar, LiDAR, multibeam echosounder (MBES), and camera—to create a visualization for further analysis. For this purpose, we took measurements from sensors installed on an autonomous, unmanned hydrographic vessel, and then proposed a data fusion mechanism, to create a visualization using modules under and above the water. A fusion contains key-point analysis on classic images and sonars, augmentation/reduction of point clouds, fitting data and mesh creation. Then, we also propose an analysis module that can be used to compare and extract information from created visualizations. The analysis module is based on artificial intelligence tools for the classification tasks, which helps in further comparison to archival data. Such a model was tested using various techniques to achieve the fastest and most accurate visualizations possible in simulation and real case studies.
Spatio-Temporal Validation of GNSS-Derived Global Ionosphere Maps Using 16 Years of Jason Satellites Observations
- Mateusz Poniatowski
- Grzegorz Nykiel
- Claudia Borries
- Jędrzej Szmytkowski
2023 Pełny tekst Remote Sensing
Existing ionospheric models perform very well in mapping the calm state of the ionosphere. However, the problem is accurately determining the total electron content (TEC) for disturbed days. Knowledge of the exact electron density is essential for single−frequency receivers, which cannot eliminate the ionospheric delay. This study aims to investigate temporal and spatial variability in the distribution of TEC based on differences between maps of individual Ionospheric Associated Analysis Centers (IAACs) of the International GNSS Service (IGS) and aligned altimetry−TEC from 2005–2021. Based on the temporal distribution, we have observed a significant effect of solar activity on the mean and standard deviation behavior of the differences between global ionospheric maps (GIMs) and Jason−derived TEC. We determined the biases for the entire calculation period, through which it can be concluded that the upcg-Jason and igsg-Jason differences have the lowest standard deviation (±1.81 TECU). In addition, the temporal analysis made it possible to detect annual, semi−annual, and 117-day oscillations occurring in the Jason−TEC data, as well as 121-day oscillations in the GIMs. It also allowed us to analyze the potential sources of these cyclicities, solar and geomagnetic activity, in the case of the annual and semi−annual periodicities. When considering spatial variations, we have observed that the most significant average differences are in the intertropical areas. In contrast, the smallest differences were recorded in the southern hemisphere, below the Tropic of Capricorn (23.5°S). However, the slightest variations were noted for the northern hemisphere above the Tropic of Cancer (23.5°N). Our research presented in this paper allows a better understanding of how different methods of GNSS TEC approximation affect the model’s accuracy.
Spawalność ferrytyczno-austenitycznej stali odpornej na korozję typu dupleks 2205 w warunkach podwodnych
- Karolina Prokop-Strzelczyńska
2023 Pełny tekst
Praca dotyczy problemów spawalności stali odpornej na korozję typu dupleks w warunkach spawania mokrego elektrodami otulonymi i lokalną komorą suchą. Całość rozprawy składa się z dwóch części. Część pierwsza to przegląd literatury, w którym omówiono główne problemy wynikające z przeniesienia procesu spawania pod wodę oraz sposoby minimalizowania negatywnego wpływu środowiska. Część druga jest częścią doświadczalną, zawiera tezę i cele rozprawy, a także charakterystykę badanych materiałów, opis metodyki badań oraz wyniki wraz z ich omówieniem. Do badań zastosowano stal dupleks 1.4462, którą poddano badaniom spawalności metodą Tekken oraz zmiennej sztywności w warunkach podwodnych jak i na powietrzu. Próby wykonano w oparciu o dwie metody, tj. elektrodami otulonymi (MMA), metodą Lokalnej Komory Suchej w warunkach podwodnych i na powietrzu. Wykonano pomiary zawartości wodoru dyfundującego w stopiwie oraz badania struktur każdej próbki. Złącza poddano badaniom wizualnym i penetracyjnym oraz badaniom metalograficznym makro- i mikroskopowym. Próbki o zmieniającej się sztywności poddano badaniom fraktograficznym przełomów. Wykazano, że spawalność stali dupleks w warunkach podwodnych elektrodami otulonymi jest ograniczona z uwagi na utrudnioną spawalność technologiczną. Stwierdzono również, że zastosowanie metody LKS skutecznie ułatwia uzyskanie złączy, spełniających odpowiednie wymagania norm przedmiotowych.
Special Issue on “Advanced Liquid Waste and Gas Waste Treatment Processes”
- Piotr Rybarczyk
2023 Pełny tekst Processes
The editorial contains a short review of the content of the Special Issue on waste gas and liquid streams treatment strategies.
Spectrum Sensing Based on Hybrid Spectrum Handoff in Cognitive Radio Networks
- Lakshminarayanan Vaduganathan
- Shubhangi Neware
- Przemysław Falkowski-Gilski
- Parameshachari Bidare Divakarachari
2023 Pełny tekst ENTROPY
The rapid advancement of wireless communication combined with insufficient spectrum exploitation opens the door for the expansion of novel wireless services. Cognitive radio network (CRN) technology makes it possible to periodically access the open spectrum bands, which in turn improves the effectiveness of CRNs. Spectrum sensing (SS), which allows unauthorized users to locate open spectrum bands, plays a fundamental part in CRNs. A precise approximation of the power spectrum is essential to accomplish this. On the assumption that each SU’s parameter vector contains some globally and partially shared parameters, spectrum sensing is viewed as a parameter estimation issue. Distributed and cooperative spectrum sensing (CSS) is a key component of this concept. This work introduces a new component-specific cooperative spectrum sensing model (CSCSSM) in CRNs considering the amplitude and phase components of the input signal including Component Specific Adaptive Estimation (CSAE) for mean squared deviation (MSD) formulation. The proposed concept ensures minimum information loss compared to the traditional methods that consider error calculation among the direct signal vectors. The experimental results and performance analysis prove the robustness and efficiency of the proposed work over the traditional methods.
Speed estimation of a car at impact with a W-beam guardrail using numerical simulations and machine learning
- Dawid Bruski
- Łukasz Pachocki
- Adam Ścięgaj
- Wojciech Witkowski
2023 Pełny tekst ADVANCES IN ENGINEERING SOFTWARE
This paper aimed at developing a new method of estimating the impact speed of a passenger car at the moment of a crash into a W-beam road safety barrier. The determination of such a speed based on the accident outcomes is demanding, because often there is no access to full accident data. However, accurate determination of the impact speed is one of the key elements in the reconstruction of road accidents. A machine learning algorithm was used to create the speed estimation model. The model was based on regression trees algorithms, with base regressors forming a final voting ensemble. The model was trained, validated, and tested using a database containing results from full-scale crash tests and numerical simulations. The developed machine learning model had a mean absolute error of 6.76 km/h with a standard deviation of 1.01 km/h on the cross-validation set, and a coefficient of determination, R2, of 0.85. This model was used to estimate the impact speed of the vehicle in three real road accidents with the W-beam barrier, and then the determined speeds were used in additional simulations to verify the results. A good quantitative and qualitative agreement between the simulation and accident outcomes was achieved, and this confirmed that the proposed method and the developed ML models combined with numerical simulations and full-scale crash tests can be effective tools for estimating the speed of the vehicle at impact with a roadside barrier.
Spike patterns and chaos in a map-based neuron model
- Piotr Bartłomiejczyk
- Frank Llovera Trujillo
- Justyna Signerska-Rynkowska
2023 Pełny tekst International Journal of Applied Mathematics and Computer Science
The work studies the well-known map-based model of neuronal dynamics introduced in 2007 by Courbage, Nekorkin and Vdovin, important due to various medical applications. We also review and extend some of the existing results concerning β-transformations and (expanding) Lorenz mappings. Then we apply them for deducing important properties of spike-trains generated by the CNV model and explain their implications for neuron behaviour. In particular, using recent theorems of rotation theory for Lorenz-like maps, we provide a classification of periodic spiking patterns in this model.
Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)2Pt(CN)4] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks
- Adrian Olejnik
- Wioletta Kopeć
- Dominik Maskowicz
- Mirosław Sawczak
2023 ACS Applied Materials & Interfaces
Paramount spin-crossover properties of the 3D-Hoffman metalorganic framework (MOF) [Fe(pz)2Pt(CN)4] are generally described on the basis of the ligand field theory, which provides adequate insight into theoretical and simulation analysis of spintronic complexes. However, the ligand field approximation does not take into account the 3D periodicity of the actual complex lattice and surface effects and therefore cannot predict a full-scale periodic structure without utilizing more advanced methods. Therefore, in this paper, the electronic properties of the exemplar MOF were analyzed from the band structure perspective in low-spin (LS) and high-spin (HS) states. The density-of-states spectra determined for both spin-up and spin-down electrons of Fe d6 orbitals indicate spin–orbital splitting and delocalization for HS due to spin polarization in the iron atom ligand field. Presence of the surface states in the real crystal causes a red shift of the metal–metal charge transfer (MMCT) and metal–ligand charge transfer (MLCT) peaks for both HS and LS states. The addition of residual water molecules and disorder among the pyrazine rings reveal additional influences on the positions of the pyrazine band and, therefore, on the absorption spectra of the crystal. The results show a magnification of the peak correlated with the MLCT in the HS state and a significant red shift of the LS characteristic absorption band. The presented approach involving band structure analysis delivers a more complete image of the electronic properties of the [Fe(pz)2Pt(CN)4] crystalline network and can be a landmark for insightful studies of other MOFs
Splice variants of mitofusin 2 shape the endoplasmic reticulum and tether it to mitochondria
- Déborah Naón
- María Isabel Hernández-Alvarez
- Satoko Shinjo
- Miłosz Wieczór
- Saska Ivanova
- Olga Martins de Brito
- Albert Quintana
- Juan Hidalgo
- Manuel Palacín
- Pilar Aparicio
- Juan Castellanos
- Luis Lores
- David Sebastián
- Sonia Fernández-Veledo
- Joan Vendrell
- Jorge Joven
- Modesto Orozco
- Antonio Zorzano
- Luca Scorrano
2023 SCIENCE
In eukaryotic cells, different organelles interact at membrane contact sites stabilized by tethers. Mitochondrial mitofusin 2 (MFN2) acts as a membrane tether that interacts with an unknown partner on the endoplasmic reticulum (ER). In this work, we identified the MFN2 splice variant ERMIT2 as the ER tethering partner of MFN2. Splicing of MFN2 produced ERMIT2 and ERMIN2, two ER-specific variants. ERMIN2 regulated ER morphology, whereas ERMIT2 localized at the ER-mitochondria interface and interacted with mitochondrial mitofusins to tether ER and mitochondria. This tethering allowed efficient mitochondrial calcium ion uptake and phospholipid transfer. Expression of ERMIT2 ameliorated the ER stress, inflammation, and fibrosis typical of liver-specific Mfn2 knockout mice. Thus, ER-specific MFN2 variants display entirely extramitochondrial MFN2 functions involved in interorganellar tethering and liver metabolic activities.
Społeczny wymiar adaptacji do zmian klimatu w środowisku miejskim na przykładzie Gdańska
- Małgorzata Dymnicka
- Paweł Starosta
- Jarosław Załęcki
2023 Pełny tekst PRZEGLĄD SOCJOLOGICZNY
Kwestie zmian klimatycznych przestały być przedmiotem zainteresowania jedynie wąskich grup specjalistów, a stały się problemem społecznym angażującym szerszą opinię publiczną. Wobec wzrastającego znaczenia problemów środowiskowych w społeczeństwach, głównie na przełomie XX i XXI wieku, władze centralne we współpracy z samorządami miejskimi zaczęły podejmować działania na rzecz wsparcia tzw. środowiskowej (zielonej) polityki. Artykuł poświęcony jest charakterystyce stanu świadomości ekologicznej mieszkańców Gdańska. Autorzy przedstawiają wnioski ze zrealizowanych badań na temat wybranych zagadnień związanych ze zmianami klimatycznymi. W pierwszej części tekstu przywołują opracowania dotyczące kwestii klimatycznej i jej obecności w dyskursie ekologicznym, który w ostatnich dwóch dekadach angażuje coraz więcej podmiotów podejmujących działania na rzecz ochrony środowiska przyrodniczego. W drugiej części skupiają uwagę na analizie empirycznej zachowań proekologicznych i ich uwarunkowań społecznych.
Spray-Based Method for Protecting and Restoring Historic Adobe Walls Using Nanomontmorillonite Clay
- Mona Khasar
- Hamed Niroumand
- Maryam Afsharpour
- Lech Bałachowski
2023 Pełny tekst ACS NANO
Restoringandprotectinghistoricbuildingsworldwideareimportant becauseheritagebuildingsarerecordsofthecivilizationsofvariouscountries.Herein, nanotechnologywasusedtorestorehistoricadobewalls.AccordingtotheIranPatent andTrademarkOffice(IRPATENT)102665,nanomontmorilloniteclayhasbeen selectedasanaturalandcompatiblematerialwithadobe.Furthermore,ithasbeenused asnanospraytobeaminimallyinvasivemethodtofillcavitiesandcracksintheadobe surface.Variouspercentagesofnanomontmorilloniteclay(1−4%)intheethanolsolvent andthefrequencyofsprayingonthewallsurfacewereevaluated.Scanningelectron microscopyandatomicforcemicroscopyimages,porositytests,watercapillary absorption,andcompressivestrengthtestswereusedtoevaluatetheefficiencyofthe method,analyzecavityfilling,anddetecttheoptimalpercentageofnanomontmorillonite clay.Resultsindicatethatthedoubleuseofthe1%nanomontmorilloniteclaysolution exhibitedthebestresults,filledthecavities,andreducedtheporesonthesurfaceofthe adobe,increasingcompressivestrengthandreducingwaterabsorptionandhydraulic conductivity.Theuseofamoredilutesolutioncausesthenanomontmorilloniteclaytopenetratedeeplyintothewall.This innovativemethodcanhelpmitigatetheexistingdisadvantagesofhistoricadobewalls.
Stability Enhancement of Grid-Connected Wind Power Generation System Using PSS, SFCL and STATCOM
- Muhammad Sarwar
- Muhammad Arshed
- Babar Hussain
- Muhammad Rasheed
- Hanan Tariq
- Stanisław Czapp
- Sarmad Tariq
- Intisar Ali Sajjad
2023 Pełny tekst IEEE Access
The stability related issues may occur in a power system due to disturbances in generating or loading conditions, especially in the presence of distributed generation (DG) based on renewable energy resources (RERs). This paper proposes a novel strategy for the stability enhancement of a wind power generation system (WPGS) by using a combination of three devices, namely, a power system stabilizer (PSS), resistive superconductor fault current limiter (R-SFCL) and static synchronous compensator (STATCOM). The small signal (SS) stability of the test system is enhanced by selecting the best PSS type from the different types of PSS. An R-SFCL is used for improving the rotor angle and the frequency stability of the test system. Two indices, namely, transient stability index and sum of maximum deviations (SMD) index are introduced for determining the optimal locations of different sized R-SFCLs for increasing the rotor angle stability. The sensitivity index (SI) based on the power change between areas is applied for determining the optimal locations of different sized R-SFCLs for enhancing the frequency stability. Along with rotor angle and frequency stability, LVRT capability improvement of the wind farm using STATCOM is also considered. Finally, the combined effect of R-SFCL and STATCOM on the rotor angle and the frequency stability, for different fault locations, is also investigated for determining the optimal location of an R-SFCL in the presence of STATCOM. The results presented in the paper show that STATCOM affects both the number of feasible locations and the optimal locations that can be selected for different sized R-SFCLs for augmenting the rotor angle and the frequency stability of the system during faults. Moreover, it is pointed out that an optimal combination between the different sizes and the locations of R-SFCLs and STATCOM exists to enhance the overall stability of the test system under fault conditions.
Stability Investigation of the PCM Nanocomposites
- Janusz Cieśliński
- Paulina Boroń
- Maciej Fabrykiewicz
2023 Pełny tekst Acta Mechanica et Automatica
Ensuring the stability is a key issue to be solved for the technical application of nanocomposites. In this work, fatty acid P1801 served as base phase change material (PCM)P1801, and its main ingredients are palmitic acid (58%) and stearic acid (38%). Titania (TiO2) and alumina (Al2O3) with mass concentrations of 1% and 5% were selected as nanoparticles, while polyvinylpyrrolidone (PVP) or oleic acid (OA) with mass concentrations of 5% were tested as surfactants. On the basis of the measured temperature distributions in the sample, which is subject to melting and solidification processes, it was determined which of the tested nanocomposites are stable and which are not. In addition, a thermal test was proposed to assess the stability of the produced nanoPCM, which consists in measuring the temperature distribution versus time according to a precisely given procedure.
State Interventionism in Tax System - Example of Action in a COVID-19 Crisis
- Piotr Kasprzak
2023 Pełny tekst International Journal of Social Science
The following article presents and classifies changes in tax systems of selected countries as well as counts them as the response to the emergence of the crisis caused by the COVID-19 pandemic. Such actions were undertaken the context of state interventionism in the tax system. In order to achieve the objective of presenting the state interventionism in the context of tax rates, an analysis of the literature on the phenomenon described, as well as specialised industry reports, were analysed. Among the research methods used are literature studies as well as review and an analysis of reports published by the OECD that dealt with the subject described and analysed in the paper. The article focuses on the presentation of the change in the individual tax burden in the countries selected for analysis. It also focuses on the presentation of tax interventionism as an opportunity for the state to influence the economy against the negative effects of the crisis. It should be noted that crises and crisis situations play an crucial role in the economic life of a country, but their course and ultimate consequences depend on the measures taken by individual countries to reduce the negative effects of their outbreak. The COVID-19 pandemic had a significant impact on changing the macroeconomic perspective and situation of many countries around the globe. The pandemic outbreak had also a negative impact on the functioning of companies (especially SME sector). As a result, governments have decided to introduce various relief measures, including changes in the functioning of tax systems. This should be considered as the state interventionism.
Static in vitro digestion model adapted to the general older adult population: an INFOGEST international consensus
- O Ménard
- U Lesmes
- C. S. Shani-Levi
- A. Araiza Calahorra
- A. Lavoisier
- M. Morzel
- A. Rieder
- G. Feron
- S. Nebbia
- L. Mashiah
- Ana Andres
- G. Bornhorst
- F Carriere
- L Egger
- S. Gwala
- Ana Heredia
- B Kirkhus
- Adam Macierzanka
- R Portmann
- I Recio
- V. Santé-Lhoutellier
- C. Tournier
- A. Sarkar
- A Brodkorb
- Alan Mackie
- D Dupont
2023 Pełny tekst Food & Function
Understanding the mechanisms of food digestion is of paramount importance to determine the effect foods have on human health. Significant knowledge on the fate of food during digestion has been generated in healthy adults due to the development of physiologically-relevant in vitro digestion models. However, it appears that the performance of the oro-gastrointestinal tract is affected by ageing and that a model simulating the digestive conditions found in a younger adult (<65 years) is not relevant for an older adult (>65 years). The objectives of the present paper were: (1) to conduct an exhaustive literature search to find data on the physiological parameters of the older adult oro-gastrointestinal tract, (2) to define the parameters of an in vitro digestion model adapted to the older adult. International experts have discussed all the parameters during a dedicated workshop organized within the INFOGEST network. Data on food bolus properties collected in the older adult were gathered, including food particle size found in older adult boluses. In the stomach and small intestine, data suggest that significant physiological changes are observed between younger and older adults. In the latter, the rate of gastric emptying is slowed down, the pH of the stomach content is higher, the amount of secretions and thus the hydrolytic activities of gastric and intestinal digestive enzymes are reduced and the concentration of bile salts lower. The consensus in vitro digestion model of the older adult proposed here will allow significant progress to be made in understanding the fate of food in this specific population, facilitating the development of foods adapted to their nutritional needs. Nevertheless, better foundational data when available and further refinement of the parameters will be needed to implement the proposed model in the future.
Static Shape and Stress Control of Trusses with Optimum Time, Actuators and Actuation
- Najmadeen Saeed
- Ahmed Manguri
- Marcin Szczepański
- Robert Jankowski
- Barham. A. Haydar
2023 Pełny tekst International Journal of Civil Engineering
Traditional shape and stress control of structures use many actuators and require enormous time to find reasonable solutions that need designers to input specific target displacement and stress. This study employs a linear technique to static shape and stress control of pin-jointed assemblies as a theoretical advancement to prior works and provides a comparative analysis against previously established works. The study evaluates the proposed method using MATLAB to find the optimum set of actuators, and MATLAB and SAP2000 to verify the actuation results obtained through applying the set of actuations to the numericalmodels. The proposed method minimizes the number of trials, count of actuators, and total actuation up to 83%, 73%, and 50%, respectively. Furthermore, the optimum solution could be found in a single trial. The study focuses on the three aspects: (a) finding the optimal count of actuators; (b) optimum amount of actuation using fmincon function; and c) Implementing two-sided inequalities to control equations allowing designers to develop target internal forces and nodal displacements, as domains rather than specific numbers. This improves the optimization process affecting actuator count, total actuation elements, and processing time.
Statistical evaluation of the changes in cellulose properties caused by the stepwise solvent exchange and esterification
- Stefan Cichosz
- Katarzyna Dems-Rudnicka
- Marcin Łapiński
- Aleksandra Jastrzębska
- Anna Masek
2023 INDUSTRIAL CROPS AND PRODUCTS
The objective of the research was to empirically confirm the changes in cellulose reactivity caused by the pre-treatment with solvents of different polarity. Therefore, 5 solvents varying in their polar component of surface tension from 0 to 4.6 mN/m were chosen. Their impact on the biopolymer properties was carefully analysed concerning chemical structure, crystallinity and surface characteristics. It was revealed that the length of 6OH⋯O3′ intermolecular H-bonds increased upon each solvent-exchange from (0.2748 ± 0.0001) nm to approx. 0.2760 nm for non-polar solvents, hence, potentially affecting cellulose structure and availability of active centres capable of reaction. As a consequence of structural variations, dioxane- and toluene-exchanged cellulose exhibited, respectively, the lowest (around 0.6 mJ/m2) and the highest (approx. 3.1 mJ/m2) polar component of surface free energy. Therefore, these samples were esterified. Further investigation successfully confirmed expected differences. Toluene-exchanged sample exhibited degree of substitution oscillating around 20%, while dioxane-exchanged specimen – approx. 7%.
Steady-State Vibration Level Measurement of the Five-Phase Induction Machine during Third Harmonic Injection or Open-Phase Faults
- Adam Muc
- Marcin Morawiec
- Filip Wilczyński
2023 ENERGIES
Multiphase electric machines are increasingly used in various industries and for electromobility. Complex systems have been developed for the control and powering of multiphase machines, which require verification. The quality of control and the power supply of electric machines is usually evaluated by analyzing various electrical parameters. On the other hand, taking into account the fact that a motor is an electrical-mechanical object, its full diagnostics should also include the analysis of vibration signals to verify the operation of the motor as a mechanical device. In this paper, a sensorless control algorithm was studied and applied to a 5-phase induction motor. Various scenarios were considered; in particular, the operation of the studied motor in the absence of one or two phases and in the case of the introduction of the third harmonic to increase the torque was analyzed. In the scenarios considered, the motor was connected to another machine and operated with no load as well as with a preset load. The results obtained were analyzed in the time and frequency domain and were related to the standards used.