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Challenges and recent advances in bio-based isocyanate production.
- Joanna Niesiobędzka
- Janusz Datta
2023 Pełny tekst GREEN CHEMISTRY
Polyurethanes (PUs) are key players in the plastics industry. According to the Global Polyurethane Market (2019–2023), their value in the global market reached $95.13 billion in 2019 and is expected to grow at a compound annual growth rate of 12%. This is in line with the increase in the number of research papers and patents on the synthesis and application of petroleum-based PUs (P-PUs) and biomass or green PUs (G-PUs) (from 67 657 to 79 468, and from 198 810 to 226 164 for papers and patents, respectively, just over the past decade). Environmental concerns about fossil-based isocyanates are the reason why investigations on their green counterparts have got receiving more attention. According to statistics, almost 8% of research papers published on PUs between 2015 and the present used green-based resources. However, no comprehensive report or review dealt with such an important field in the chemistry of polyurethanes. This review highlights and reviews the production of isocyanate compounds directly from biomass. Moreover, various methods applied in the synthesis of bio-derived isocyanates are discussed. Technically, we discuss the main difficulties in the synthesis of biomass-based PUs. To address sustainability concerns, we overview the whole range of isocyanate compounds economically viable for biomass-based synthesis. We believe that the elimination of phosgene is a key to the production of green PUs. However, there is still a long way to go to develop green PUs with properties and performance comparable to fossil-based ones.
Channel Impulse Response Measurements at mmWave Band in Office and Conference Rooms
- Monika Drozdowska
- Sławomir Ambroziak
- Krzysztof Cwalina
- Piotr Rajchowski
- Narcis Cardona
2023 Pełny tekst
In this paper, the measurements of the channel impulse response at mmWave band in office and conference rooms are described. The central frequency is 27 GHz with a bandwidth of 400 MHz. The description of the used measurement stand and considered environments are presented. The initial analysis of the power delay profile, mean delay, and RMS delay spread allows preliminary conclusions to be drawn that there is a significant impact of the dimensions of the rooms on these parameters.
Characterization of Bioactivity of Selective Molecules in Fruit Wines by FTIR and NMR Spectroscopies, Fluorescence and Docking Calculations
- Kim Young-mo
- Martyna Lubinska-Szczygeł
- Yong-Seo Park
- Joseph Deutsch
- Aviva Ezra
- Patraporn Luksirikul
- Rajamohamed Beema Shafreen
- Shela Gorinstein
2023 Pełny tekst MOLECULES
Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopies were applied to characterize and compare the chemical shifts in the polyphenols’ regions of some fruit wines. The obtained results showed that FTIR spectra (1800–900 cm−1) and 1H NMR (δ 6.5–9.3 ppm) of different fruit wines can be used as main indices of the year of vintage and quality of fruit wines. In addition to the classical determination of antioxidant profiles and bioactive substances in wines, fluorometric measurements were used to determine the interactions of wine substances with the main human serum proteins. The results showed relatively high binding properties of wines with the highest one for pomegranate, followed by kiwifruit and persimmon wines. The interactions of vitamin C, catechin and gallic acid with human serum albumin (HSA) were also examined by docking studies. The docking calculations showed that gallic acid has a stronger binding affinity compared to catechin and vitamin C. The stronger binding affinity of gallic acid may be due to three hydrogen bonds and pi–pi interactions. The fluorescence and docking studies proved that only the bioactive compounds of wines and not the amount of alcohol have high binding properties to human serum proteins. The emphasis in this report was made on the utility of FTIR, NMR and fluorescence of wines as a mean of wine authentication and its fingerprint. The findings, based on polyphenols from fruits and fruit wines, their bioactivity and health properties, offer valuable insights for future endeavours focused on designing healthy food products.
Characterization of GM3 Gangliosides in Human Milk throughout Lactation: Insights from the Analysis with the Use of Reversed-Phase Liquid Chromatography Coupled to Quadrupole Time-Of-Flight Mass Spectrometry
- Weronika Hewelt-Belka
- Michał Młynarczyk
- Dorota Garwolińska
- Agata Kot-Wasik
2023 Pełny tekst JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
Gangliosides are complex lipids found in human milk that play important structural and biological functions. In this study, we utilized reversed-phase liquid chromatography coupled to quadrupole time-of-flight mass spectrometry to evaluate the molecular distribution of GM3 in human milk samples collected at distinct lactation stages, ranging from colostrum to advanced lactation samples. Throughout lactation, GM3 d40:1 emerged as the most abundant GM3 species, except in colostrum, where GM3 d42:2 prevailed. The relative content of GM3 species containing very long N-fatty acyl (N-FA) substituents with >22 carbon atoms decreased, while the content of GM3 species containing 14:0, 18:0, 18:1, and 20:0 N-FA substituents increased in the later months of lactation. These findings highlight the divergence of GM3 profiles across the lactation period. Moreover, considerable interindividual variance was observed among the analyzed samples. The assessment of the GM3 profiles contributes to our understanding of the dynamic composition of human milk.
Characterizing the Scalability of Graph Convolutional Networks on Intel® PIUMA
- Matthew Joseph Adiletta
- Jesmin Jahan Tithi
- Emmanouil-Ioannis Farsarakis
- Gerasimos Gerogiannis
- Robert Adolf
- Robert Benke
- Sidharth Kashyap
- Samuel Hsia
- Kartik Lakhotia
- Fabrizio Petrini
- Gu-Yeon Wei
- David Brooks
2023
Large-scale Graph Convolutional Network (GCN) inference on traditional CPU/GPU systems is challenging due to a large memory footprint, sparse computational patterns, and irregular memory accesses with poor locality. Intel’s Programmable Integrated Unffied Memory Architecture (PIUMA) is designed to address these challenges for graph analytics. In this paper, a detailed characterization of GCNs is presented using the Open-Graph Benchmark (OGB) datasets to determine the viability of PIUMA as a potential solution to GCN scalability. First, the extent of sparse matrix dense matrix multiplication (SpMM) as a performance driver for GCN on CPU and GPU is explored, offering a methodology for predicting GCN behavior as a function of dataset characteristics. Second, an SpMM kernel optimized for PIUMA is described and investigated for sensitivity to system parameters including memory bandwidth, latency, and thread count. SpMM scalability on PIUMA is demonstrated, while the scalability limitations of a Xeon-optimized SpMM implementation are discussed. Finally, GCN performance is compared on PIUMA versus a Xeon CPU system and Ampere GPU system, showing impressive results on PIUMA for largescale datasets.
Charge density wave and crystalline electric field effects in TmNiC2
- Marta Roman
- Maria Fritthum
- Berthold Stöger
- Devashibhai T. Adroja
- Herwig Michor
2023 Pełny tekst PHYSICAL REVIEW B
Single crystals of TmNiC2 were grown by the optical floating-zone technique and were investigated by x-ray diffraction (XRD), thermal expansion, electrical resistivity, specific heat, and magnetic susceptibility measurements. Single-crystal XRD reveals the formation of a commensurate charge density wave (CDW) characterized by a CDW modulation vector q2c = (0.5, 0.5, 0.5), which is accompanied by a symmetry change from the orthorhombic space group Amm2 to the monoclinic space group Cm, i.e., to a CDW superstructure which is isostructural with that of LuNiC2 . For all transport and thermodynamic properties, anomalies related to a second order-type thermodynamic CDW phase transition are observed at around TCDW = 375 K. The large specific heat anomaly at TCDW, deltaC = 6.2 J mol−1 K−1 , together with noticeable changes in entropy and enthalpy related to the CDW transition, suggests that this point group symmetry breaking CDW phase transition affects more significant parts of the Fermi surface as compared to the incommensurate CDW transition of, e.g., SmNiC2 with no change in point group symmetry. The results on the antiferromagnetic and paramagnetic state of TmNiC2 obtained by the above macroscopic techniques were complemented by microscopic studies via inelastic neutron scattering. A crystalline electric field modeling of macroscopic susceptibility and magnetic specific heat and entropy contributions as well as microscopic neutron scattering data, reveal crystal field eigenstates and eigenvalues with a ground-state doublet of the Tm-4f electrons, which is well separated by about 25 meV from exited states of the J = 6 ground-state multiplet.
Charge Transport in High-Entropy Oxides
- Wojciech Skubida
- Daniel Jaworski
- Aleksandra Mielewczyk-Gryń
- Sebastian Wachowski
- Tadeusz Miruszewski
- Kacper Cichy
- Konrad Swierczek
- Maria Gazda
2023 Pełny tekst Journal of Physical Chemistry C
This work presents the results of research on the transport properties of the high-entropy BaZr1/8Hf1/8Sn1/8Ti1/8Y1/8In1/8Sm1/8Yb1/8O3–x perovskite oxide with special focus on proton transport. The presented study is part of broader work in which we focus on multiple different chemical compositions with the cation number varying from 5 up to 12 (in B-sublattice). The presence of proton defects is analyzed with thermogravimetry, whereas the results of electrochemical impedance spectroscopy in dry, H2O-, and D2O-containing synthetic air in the 300–800 °C temperature range enable the evaluation of the proton and deuterium conductivities. The isotope effect is observed and discussed. The obtained data allow us to establish the contribution of proton conductivity to the total one and the transport numbers for proton/deuterium conductivity. Based on the bulk and grain boundary conductivities, the potential at a grain boundary φ0, Debye length LD, and space-charge layer (SCL) thickness λ for proton defects is calculated. The potential barrier heights were found to be significantly lower than those observed for typical polycrystalline-doped barium zirconates. For the first time in the case of high-entropy oxides, the electrical conductivity relaxation (ECR) studies are performed, allowing the calculation of water kinetic coefficients. The ECR in the 300–600 °C temperature range revealed a single-fold nature, which indicates a negligible component of the electronic hole conductivity in the hydrated material. The chemical diffusion coefficient of water DOH• and the chemical surface exchange coefficient of water kOH• along with their activation energies are determined. The chemical diffusion coefficient DOH• is in a range of 10(1)−8–10(1)−6 cm2 s–1, and the chemical surface exchange coefficient kOH• is in a range of 10(1)−6–10(1)−4 cm s–1.
ChatGPT Application vis-a-vis Open Government Data (OGD): Capabilities, Public Values, Issues and a Research Agenda
- Euripidis Loukis
- Stuti Saxena
- Nina Rizun
- Maria Ioanna Maratsi
- Mohsan Ali
- Charalampos Harris Alexopoulos
2023
As a novel Artificial Intelligence (AI) application, ChatGPT holds pertinence not only for the academic, medicine, law, computing or other sectors, but also for the public sector-case in point being the Open Government Data (OGD) initiative. However, though there has been some limited (as this topic is quite new) research concerning the capabilities ChatGPT in these sectors, there has been no research about the capabilities it can provide to government concerning its wide range of functions and activities. This paper contributes to filling this gap by investigating the capabilities that the ChatGPT can provide concerning one of most recently initiated and novel, and at the same time most promising, activities of government that aims to fuel the emerging data economy and society: the opening of large amounts of government data; furthermore, we investigate the public values that can be promoted through the use of ChatGPT in the area of OGD by both the data publishers as well as their users. At the same time, we investigate the issues that the use of ChatGPT in the area of OGD can pose, which can reduce the capabilities identified as aforesaid as well as the benefits and public values that can be generated from them. For these purposes interviews with 12 experts have been conducted and their responses have been analyzed. Finally, based on our findings we have developed a research agenda concerning the exploitation of ChatGPT application in the OGD domain
Chemical, Aroma and Pro-Health Characteristics of Kaffir Lime Juice—The Approach Using Optimized HS-SPME-GC-TOFMS, MP-OES, 3D-FL and Physiochemical Analysis
- Martyna Lubinska-Szczygeł
- Żaneta Polkowska
- Małgorzata Rutkowska
- Shela Gorinstein
2023 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
The study aimed to provide the chemical, aroma and prohealth characteristics of the kaffir lime juice. A procedure using solid-phase microextraction with gas chromatography (SPME-GC-TOFMS) was optimized and validated for the determination of terpenes of kaffir lime. Main physicochemical parameters: pH, vitamin C, citric acid and °Brix were evaluated. Micro- and macro elements were determined using microwave plasma optic emission spectrometry (MP-OES). The binding of kaffir lime terpenes to human serum albumin (HSA) was investigated by fluorescence spectroscopy (3D-FL). β-Pinene and Limonene were selected as the most abundant terpenes with the concentration of 1225 ± 35 and 545 ± 16 µg/g, respectively. The values of citric acid, vitamin C, °Brix and pH were 74.74 ± 0.50 g/kg, 22.31 ± 0.53 mg/100 mL, 10.35 ± 0.70 and 2.406 ± 0.086 for, respectively. Iron, with a concentration of 16.578 ± 0.029 mg/kg, was the most abundant microelement. Among the macroelements, potassium (8121 ± 52 mg/kg) was dominant. Kaffir lime binding to HSA was higher than β-Pinene, which may indicate the therapeutic effect of the juice. Kaffir lime juice is a source of terpenes with good aromatic and bioactive properties. Fluorescence measurements confirmed its therapeutic effect. Kaffir lime juice is also a good source of citric acid with potential industrial application. The high content of minerals compared to other citruses increases its prohealth value.
Chemical Characteristics and Thermal Oxidative Stability of Novel Cold-Pressed Oil Blends: GC, LF NMR, and DSC Studies
- Wojciech Cichocki
- Dominik Kmiecik
- Hanna Maria Baranowska
- Hanna Staroszczyk
- Agata Sommer
- Przemysław Łukasz Kowalczewski
2023 Pełny tekst Foods
Plant oils contain a high content of unsaturated fatty acids. Studies of food products have revealed a considerable disproportion in the ratio of ω6 to ω3. This article presents information on the healthful qualities of eight new oil blends that contain a beneficial proportion of ω6 to ω3 fatty acids (5:1), as well as their degradation during heating at 170 and 200 °C. The fatty acid profile was analyzed by gas chromatography (GC), content of polar compounds and polymers of triacylglycerols by liquid chromatography (LC), water content was measured by the Karl Fischer method, and oxidative stability was measured by differential scanning calorimetry (DSC) and low-field nuclear magnetic resonance (LF NMR) methods. The results showed that during heating, the polar fraction content increased in samples heated at both analyzed temperatures compared to unheated oils. This was mainly due to the polymerization of triacylglycerols forming dimers. In some samples that were heated, particularly those heated to 200 °C, trimers were detected, however, even with the changes that were observed, the polar fraction content of the blends did not go beyond the limit. Despite the high content of unsaturated fatty acids, the analyzed blends of oils are characterized by high oxidative stability, confirmed by thermoanalytical and nuclear magnetic resonance methods. The high nutritional value as well as the oxidative stability of the developed oil blends allow them to be used in the production of food, in particular products that ensure an adequate supply of ω3 fatty acids.
Chemically reduced graphene oxide based aerogels - Insight on the surface and textural functionalities dependent on handling the synthesis factors
- Maksymilian Plata Gryl
- Roberto Castro Munoz
- Grzegorz Boczkaj
2023 Pełny tekst COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
Efficient adjusting of reduced graphene oxide aerogels properties requires information about experimental factor-aerogel property relationship. In this work, the reduced graphene oxide aerogels surface and textural functionalities in relation to precursor concentration, gelation time and hydrogel freezing temperature were studied in detail, with the use of dynamic adsorption method of gaseous organic probes and experimental design. The precursor concentration and the hydrogel freezing temperature have the strongest influence on textural properties - a negative correlation with apparent surface area was observed. The highest value of 229.36 m2 g−1 was obtained for samples synthesized at the lowest concentration of precursor (2 mg mL−1) and hydrogel freezing temperature (−196 °C). Low precursor concentration promote formation of more hydrophobic aerogels. All aerogels display tendencies for dispersive, dipole-type and electron donor interactions. Moreover, a repulsion of electron lone pairs was observed, as well as shape-based selectivity (originating from porosity and surface roughness) in gas-solid adsorption process. Analysis of the free surface energy revealed that the maximum value (193.21 mJ m−2) is obtained at 7.2 mg mL−1 precursor concentration, − 104 °C hydrogel freezing temperature and 23 h gelation time. Presented findings can translate directly into reduced graphene oxide aerogels tailored for specific applications such as adsorption or catalysis.
Chitosan-based electrospun nanofibers for encapsulating food bioactive ingredients: A review
- Roberto Castro Munoz
- Mohammad Saeed Kharazmi
- Seid Mahdi Jafari
2023 Pełny tekst INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
Today, society has been more aware of healthy food products and related items containing bioactive compounds, which potentially contribute to human health. Unfortunately, the long-term stability and bioactivity of biologically active compounds against environmental factors compromise their target and effective action. In this way, lab-designed vehicles, such as nanoparticles and nanofibers, provide enough properties for their preservation and suitable delivery. Here, the electrospinning technique acts as an effective pathway for fabricating and designing nanofibers for the entrapments of biomolecules, in which several biopolymers such as proteins, polysaccharides (e.g., maltodextrin, agarose, chitosan), silk, among others, can be used as a wall material. It is likely that chitosan is one of the most employed biomaterials in this field. Therefore, in this review, we reveal the latest advances (over the last 2–3 years) in designing chitosan-based electrospun nanofibers and nanocarriers for encapsulation of bioactive compounds, along with the key applications in smart food packaging as well. Key findings and relevant breakthroughs are a priority in this review to provide a cutting-edge analysis of the literature. Finally, particular attention has been paid to the most promising developments.
Chitosan-Based Membranes as Gentamicin Carriers for Biomedical Applications — Influence of Chitosan Molecular Weight
- Milena Supernak
- Balbina Makurat-Kasprolewicz
- Beata Kaczmarek-Szczepańska
- Anna Pałubicka
- Monika Sakowicz-Burkiewicz
- Anna Ronowska
- Marcin Wekwejt
2023 Pełny tekst Membranes
Over the past decade, much attention has been paid to chitosan as a potential drug carrier because of its non-toxicity, biocompatibility, biodegradability and antibacterial properties. The effect of various chitosan characteristics on its ability to carry different antibiotics is discussed in the literature. In this work, we evaluated the influence of the different molecular weights of this polymer on its potential as an antibacterial membrane after adding gentamicin (1% w/w). Three types of chitosan membranes without and with antibiotic were prepared using a solvent casting process. Their microstructures were analyzed with a 4K digital microscope, and their chemical bonds were studied using FTIR spectroscopy. Furthermore, cytocompatibility on human osteoblasts and fibroblasts as well as antibacterial activity against Staphylococcus aureus (S. aureus.) and Escherichia coli (E. coli) were assessed. We observed that the membrane prepared from medium-molecular-weight chitosan exhibited the highest contact angle (85) and roughness (10.96 0.21 m) values, and its antibacterial activity was unfavorable. The maximum tensile strength and Young’s modulus of membranes improved and elongation decreased with an increase in the molecular weight of chitosan. Membranes prepared with high-molecular-weight chitosan possessed the best antibacterial activity, but mainly against S. aureus. For E. coli, is not advisable to add gentamicin to the chitosan membrane, or it is suggested to deplete its content. None of the fabricated membranes exhibited a full cytotoxic effect on osteoblastic and fibroblast cells. Based on our results, the most favorable membrane as a gentamicin carrier was obtained from high-molecular-weight chitosan.
Chromium (III) removal by perennial emerging macrophytes in floating treatment wetlands
- Nicole Nawrot
- Ewa Wojciechowska
- Muhammad Mohsin
- Suvi Kuittinen
- Ari Pappinen
- Karolina Matej-Łukowicz
- Katarzyna Szczepańska
- Agnieszka Cichowska
- Muhammad Atif Irshad
- Filip M. G. Tack
2023 Pełny tekst Scientific Reports
Floating treatment wetlands (FTWs) are a sustainable solution to treat polluted water, but their role in chromium (Cr(III)) removal under neutral pH conditions remains poorly understood. This study evaluated the potential of FTWs planted with two perennial emergent macrophytes, Phragmites australis and Iris pseudacorus, to remove Cr(III) and nutrients (N and PO4-P) from water containing 7.5 mg/L TN, 1.8 mg/L PO4-P, and Cr(III) (500, 1000, and 2000 µg/L). Within 1 h of exposure, up to 96–99% of Cr was removed from the solution, indicating rapid precipitation. After 50 days, Phragmites bound 9–19% of added Cr, while Iris bound 5–22%. Both species accumulated Cr primarily in the roots (BCF > 1). Biomass production and growth development were inhibited in Cr treatments, but microscopic examination of plant roots revealed no histological changes at 500 and 1000 µg/L Cr, suggesting high resistance of the tested species. At 2000 µg/L Cr, both species exhibited disruptions in the arrangement of vessel elements in the stele and increased aerenchyma spaces in Phragmites. At the end of the experiment, 70–86% of TN and 54–90% of PO4-P were removed.
Chromogenic azomacrocycles with imidazole residue: Structure vs. properties
- Błażej Galiński
- Jarosław Chojnacki
- Katarzyna Szwarc-Karabyka
- Adrian Małkowski
- Diana Sopel
- Agnieszka Zwolińska
- Ewa Wagner-Wysiecka
2023 Pełny tekst DYES AND PIGMENTS
New diazo macrocycles linked by hydrocarbon chain bearing imidazole or 4-methylimidazole residue have been synthetized with satisfactory yield (24–55%). The structure of macrocycles was confirmed by X-ray analysis and spectroscopic methods (1H NMR, MS, FTIR). Metal cation complexation studies were carried out in acetonitrile and acetonitrile-water system. It was found that azomacrocyles form triple-decker complexes with lead(II). The highest values of stability constant were found for lead(II) complexes of 21-membered derivatives. For the first time azomacrocycles bearing imidazole residue were immobilized on a porous glass. Obtained materials can act as lead(II) or copper(II) colorimetric optical sensors with color digital analysis as detection using simple portable devices.
Circularly Polarized Antenna Array design with the Potential of Gain-Size Trade-off and Omnidirectional Radiation for Millimeter-Wave Small Base Station Applications
- Ullah Ubaid
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2023 WIRELESS NETWORKS
This paper presents the design and validation of a slot-patch-hybrid circularly polarized antenna array for 28 GHz millimeter (mm) wave (mm-wave) applications. The proposed design has a simple geometry that facilitates the fabrication process, which is otherwise a challenging task due to the sub-mm dimensions of the circuit in the mm-wave band. In the proposed structure, aperture-coupled series slot-fed array is utilized to excite the 45-degrees inclined pair of patches. The feeding array aperture is designed by printing a straight microstrip feed line with a matching stub at the open end. Further, a coupling slot is etched underneath the feed line in the conventional horizontal position, and two vertical slots are merged toward each end of the slot. For realization of the series phased array of (1×(4×2)) elements, the slots are placed half guided wavelength away extending the array network along the feedline. A pair of the radiating patches are loaded on the top of the vertical slots. To ensure excitation of the 90-degree phase-shifted orthogonal field components of equal magnitude, the loaded patches are rotated by 45-degrees in the azimuth plane. The produced circularly polarized (CP) fields are further refined by an additional diagonal radiating slot etched in the middle of the pair of radiating patches parallel to the non-radiating edges. With the combination of radiating patches and the slots, a wide axial ratio bandwidth of 27.5 GHz to 28.5 GHz, broad impedance bandwidth, a highly directional beam, and a peak realized CP gain of 15.15dBic is achieved. For realizing omnidirectional radiation pattern necessary for the base station applications, 3-dimentional hexagonal/octagonal topology is utilized in six- and eight-antenna configurations. A detailed theoretical and numerical analysis and the corresponding results shows that the adjacent beams could be merged together constructively to form omnidirectional radiation patterns. The advantage of the proposed technique is the ease of implementation without affecting the major performance figures.
Classification of Sea Going Vessels Properties Using SAR Satellite Images
- Dariusz Kobiela
- Tomasz Berezowski
2023
The aim of the project was to analyze the possibility of using machine learning and computer vision to identify (indicate the location) of all sea-going vessels located in the selected area of the open sea and to classify the main attributes of the vessel. The key elements of the project were to download data from the Sentinel-1 satellite [1], download data on the sea vessels [2], then automatically tag data and develop a detection and classification algorithm. The results obtained from the YOLOv7 model on the test set were Mean Average Precision (mAP@.5) = 91% and F1-score = 93% for the single-class ship detection task. When combining the task of ship detection with a ship’s length and width classification, Mean Average Precision for all classes was 40%, f1-score was 41%
CLEANING METHODS FOR DUST DEPOSITED ON THE FRONT COVER OF PHOTOVOLTAIC MODULE
- Małgorzata Rudnicka
- Ewa Klugmann-Radziemska
2023 Pełny tekst Ecological Chemistry and Engineering S - Chemia i Inżynieria Ekologiczna S
Photovoltaic modules are one of the renewable energy sources with great potential for application in various regions of the world as well as for different terrain. They are, however, sensitive to external factors, affecting the overall amount of energy generated, such as solar irradiance, shading effects and any form of soil build-up on the front glass cover of solar device. The latter issue happens over a course of weeks, months and years and the exact pace is determined for a specific location. Nevertheless, dust remaining on the module surface limits the amount of solar irradiation that can reach solar cells. It then leads to a lowered maximum power and correspond to a decrease in energy yield. A way to mitigate soiling effect, outside of natural washing dependent on precipitation, is a regular debris removal. The proposed methods utilise different approaches, namely active cleaning such as manual, mechanical or electrodynamic, or passive cleaning by applying additional hydrophobic or hydrophilic coating to slow down the accumulation tempo.
Closed Form Constraint Equations Used to Express Frictionless Slip of Multibody Systems Attached to Finite Elements—Application to a Contact between a Double Pendulum and a Beam
- Krzysztof Lipiński
2023 Pełny tekst Applied Sciences-Basel
This paper focuses on the numerical modeling of the dynamics of mechanical systems. Robots that can inspect high-voltage lines inspired this research. Their control systems must anticipate potential grab positions appropriately. We intend to formulate equations dedicated to the numerical description of the robot/cable contact. The investigated problem is not straightforward, since parts of the modeled systems are numerically inhomogeneous. They consist of multibody and finite element components. These components interact with each other only through frictionless point contact. We limit the present investigation to the mathematical modeling of these frictionless point connections. According to the model-adopted assumption, the location of the contact point is invariant in the multibody structure, but it is variable in the finite elements part. Unlike the classically used models (i.e., spring/damper models of elastic contacts), we focus on constraint equations. We present and discuss their details in this paper. Following the presence of the constraint equations, their associated Lagrange multipliers appear in the dynamics equations of the two sub-models. The main feature/result of the presently proposed method is the closed form of the coordinateportioning formulae, proposed in this paper, employed to eliminate the dependent coordinates and the constraint-associated Lagrange multipliers. To verify the applicability of the proposed elimination methodology, we test its use in a dedicated numerical example. During the test, we limit the investigation to a frictionless connection between a double pendulum and a beam. The results confirm that the proposed methodology allows us to model the investigated frictionless contact. We shall underline a vital property, that the proposed elimination method is universal, and thus one can easily extend/modify the above methodology to operate with other multibody/finite element contacts.
Closing the gap – the opportunity for sustainability and smart transition in the Central and East Europe countries
- Paulina Duch-Żebrowska
- Katarzyna Zielonko-Jung
2023 Pełny tekst 19th Century music
For almost half a century the countries of CEE were part of- or were remaining under the influence of- the Soviet Union what caused gaping difference in the starting line towards sustainability. Here the prefabricated concrete blocks of flats were being built at the scale unseen in the western countries. Those buildings, approximately a quarter of the residential market, are in a structurally sound condition to last another five or more decades. However, during their construction, the requirements for energy efficiency were almost nonexistent. Therefore, their refurbishment and thermal upgrades is a prerequisite, and due to sustainability, the demolition should not be considered unless it is unavoidable. This paper discusses the case of one mass housing block of flats and method to find the most efficient way to bring it to the higher energy efficiency standards using the BIM simulation technology. The chosen solution might be widely implemented due to typology. The effect of the scale (any refurbishment to one block can be performed to many others of the same type) gives the opportunity to substantially cut the energy consumption and close the huge gap between the east and west European blocks on our way to a greener future.