The rotating Ring Disk Electrode (RRDE), since its introduction in 1959 by Frumkin and Nekrasov, has become indispensable with diverse applications in electrochemistry, catalysis, and material ...science. The collection efficiency ( N ) is an important parameter extracted from the ring and disk currents of the RRDE, providing valuable information about reaction mechanism, kinetics, and pathways. The theoretical prediction of N is a challenging task: requiring solution of the complete convective diffusion mass transport equation with complex velocity profiles. Previous efforts, including by Albery and Bruckenstein who developed the most widely used analytical equations, heavily relied on approximations by removing radial diffusion and using approximate velocity profiles. 65 years after the introduction of RRDE, we employ a physics-informed neural network to solve the complete convective diffusion mass transport equation, to reveal the formerly neglected edge effects and velocity corrections on N , and to provide a guideline where conventional approximation is applicable.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Kaolin is most often used as traditional raw material in ceramic industry. The purpose of the study was to obtain understanding of the structural and chemical variability of cordierite ceramics ...influenced by chemical and mineralogical properties of six raw kaolins taken from different localities when they are applied in ceramics mixtures with vermiculite and sintered up to 1300 °C. The X-ray diffraction and simultaneous thermogravimetric and differential thermal analysis were used to identify and characterize crystalline mineral phases and the course of reactions during the heating. The percentages of the crystalline and non-crystalline phases were newly determined by recalculation of the bulk chemical analyses of kaolins and cordierite ceramics using Chemical Quantitative Mineral Analysis (CQMA) method. Varying amounts of minerals in kaolins: kaolinite from 73.3 to 85.0, muscovite from 4.2 to 9.9, and quartz from 6.0 to 19.5 (mass %) affected amount of cordierite/indialite from 75.2 to 85.1, enstatite from 5.8 to 8.9 (when are calculated as their maximal possible percentages), and non-crystalline phases from 8.8 to 15.1 (mass %) in cordierite ceramics. Regression analysis predicted high relationship between quantity of: (a) kaolinite in kaolins and crystalline cordierite and (b) quartz in kaolins and non-crystalline phases in the ceramics. The migration of potassium from muscovite into the cordierite structure, melting point and crystallization of cordierite/indialite phases and pore size variability in relation to impurity of kaolins are documented and discussed.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Display omitted
•g-C3N4 (CN) was synthetized from melamine in air and nitrogen.•CN prepared in air contained the lower content of oxygen due to decarboxylation.•Oxygen was present mainly in the form ...of hydroxyl groups.•Influence of oxygen on the CN properties was investigated.
Two types of bulk graphitic carbon nitrides (CN) were synthetized by heating melamine at 550 °C for 4 h in the air (CN/air) and nitrogen (CN/N2) atmosphere for us to find the effect of present oxygen on their properties. Bulk CN was exfoliated by further heating at 500 °C for 1–3 h in air and nitrogen as well. The obtained materials were studied in terms of structural, textural and physico-chemical properties including photocatalytic activity.
The CN/air materials contained less oxygen (2.3–5.0 wt%) than the CN/N2 ones (about 7 wt%) due to decarboxylation during their synthesis and exfoliation in air. The CN/N2 materials had more structural defects, which were attacked by oxygen from the moment the materials came into contact with air. In both types of materials oxygen was supposed to be present mostly in the form of hydroxyl groups. As a result, the CN/N2 materials were slightly exfoliated and their surfaces were more hydrophilic than the CN/air ones. The photocatalytic activity of CN materials was dependent on their specific surface area (SSA). It was found that native oxygen existed in the CN materials and was important for their properties.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
One of the solutions for overheating the interior in the summer without increasing energy consumption is the integration of phase change material (PCM) into interior plasters. However, adding PCM to ...plasters deteriorates their properties and thus their usability. The aim of this paper is to determine how the microencapsulated PCM affects the mechanical, thermal, and fire properties of plasters and how much PCM can be added to the plaster. Two sets of samples were prepared: in set S, part of the aggregate was replaced by PCM; and in set R, only PCM was added. The bulk density, flexural strength, compressive strength, tensile strength perpendicular to the surface, thermal conductivity coefficient, specific heat capacity, melting, and solidification temperatures and enthalpy were measured. A single-flame source fire test and a gross heat of combustion fire test were performed to determine the reaction to the fire class. The results show that with an increasing proportion of PCM, the strength of the samples of set R decreased more significantly than it did with the samples of set S. It was found that only up to about 10% PCM could be added to set R, while up to 30% PCM could be added to set S.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Composites consisting of iron aluminide and iron silicide phases were studied in this work. Powders of iron aluminide and iron silicide were prepared by mechanical alloying separately. Subsequently, ...they were blended in three different proportions and sintered by the SPS method under various conditions. After sintering, the composites are composed of FeAl and amounts of other silicides (Fe
Si
and Fe
Si). Ternary Fe-Al-Si phases were not determined, even though their presence was predicted by DFT calculations. This disagreement was explained by steric factors, i.e., by differences in the space lattice of the present phases. Hardness and tribological properties were measured on composites with various weight ratios of iron aluminide and iron silicide. The results show that sintered silicides with the matrix composed of iron aluminide reach comparable hardness to tool steels. The composites with higher mass ratios of iron aluminide than silicide have higher hardness and better tribological properties.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Machine learning is increasingly integrated into chemistry research by guiding experimental procedures, correlating structure and function, interpreting large experimental datasets, to distill ...scientific insights that might be challenging with traditional methods. Such applications, however, largely focus on gaining insights via big data and/or big computation, while neglecting the valuable chemical prior knowledge dwelling in chemists’ minds. In this paper, we introduce an Electrochemistry‐Informed Neural Network (ECINN) by explicitly embedding electrochemistry priors including the Butler–Volmer (BV), Nernst and diffusion equations on the backbone of neural networks for multi‐task discovery of electrochemistry parameters. We applied the ECINN to voltammetry experiments of
Fe2+/Fe3+
${{\rm F}{{\rm e}}^{2+}/{\rm F}{{\rm e}}^{3+}}$
and
RuNH362+/RuNH363+
${{\rm R}{\rm u}{\left({\rm N}{{\rm H}}_{3}\right)}_{6}^{2+{\rm \ }}/{\rm R}{\rm u}{\left({\rm N}{{\rm H}}_{3}\right)}_{6}^{3+{\rm \ }}}$
redox couples to discover electrode kinetics and mass transport parameters. Notably, ECINN seamlessly integrated mass transport with BV to analyze the entire voltammogram to infer transfer coefficients directly, so offering a new approach to Tafel analysis by outdating various mass transport correction methods. In addition, ECINN can help discover the nature of electron transfer and is shown to refute incorrect physics if imposed. This work encourages chemists to embed their domain knowledge into machine learning models to start a new paradigm of chemistry‐informed machine learning for better accountability, interpretability, and generalization.
Electrochemistry‐Informed Neural Network (ECINN) embeds chemistry prior knowledge including the Butler‐Volmer, Nernst and Diffusion equations to discover electrode kinetics and mass transport parameter simultaneously from sparse experiments. ECINN seamlessly integrates mass transport and BV equation and provides arguably the best Tafel analysis method. This work encourages embedding domain knowledge to realize strong intelligence with sparse data.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Detailed analysis of the function of multilayer perceptron (MLP) and its neurons together with the use of time-varying neurons allowed the authors to find an analogy with the use of structures of ...linear differential operators. This procedure allowed the construction of a group and a hypergroup of artificial neurons. In this article, focusing on semihyperstructures and using the above described procedure, the authors bring new insights into structures and hyperstructures of artificial neurons and their possible symmetric relations.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Infinite cyclic groups created by various objects belong to the class to the class basic algebraic structures. In this paper, we construct the infinite cyclic group of differential neurons which are ...modifications of artificial neurons in analogy to linear ordinary differential operators of the n-th order. We also describe some of their basic properties.
Display omitted
•P-doped g-C3N4 was prepared using melamine and hexachlorocyclotriphosphazene (HCCP).•Initial HCCP concentration determined the nature of P in the g-C3N4 structure.•The doping ...mechanism of g-C3N4 with P using melamine and HCCP was proposed.•The optimum amount of HCCP regarding to the photodegradation activity was found.
The synthesis of P-doped graphitic carbon nitride (PCN) by in situ doping via co-pyrolysis of melamine and hexachlorocyclotriphosphazene (HCCP) is being investigated. The amount of HCCP varies between 2 and 40 wt% and the results show continuous enrichment of graphitic carbon nitride (CN) by phosphorus. The detailed characterization of prepared samples leads to the proposition of the occurrence of phosphorus in synthesized samples as well as to the proposition of a P-doping mechanism. The results of the characterization techniques used indicate that with up to 1.2 wt% of phosphorus in final PCN, phosphorus predominantly substitutes carbon in the structure. An increase of the phosphorus content to 2.44 wt% causes its incorporation into substitutional positions and part of the phosphorus occurs in other forms. PCN with 2.44 wt% of phosphorus obtained from the mixture of melamine with 20 wt% of HCCP thermally treated at 525 °C shows the highest photodegradation activity under VIS irradiation.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The interaction of Fe–C–O–Cr alloys varying in chromium (0.924–4.760 wt%) and carbon (0.042–1.378 wt%) content with a ceramic substrate having a high content of Al2O3 was studied by experimental ...wettability tests up to 1600 °C. The degree of interaction was assessed based on changes in contact angles (wetting angles) between the above systems, and through Energy Dispersive X-Ray (EDX), X-Ray Diffraction (XRD) analyses and Scanning Electron Microscopy (SEM). The increasing trend of wetting angles with increasing content of chromium and carbon was found. The results of the analyzes confirmed the effect of carbon (≥0.1 wt%) contained in the alloys on the structural changes in substrate surface within the area under the alloy. The original corundum phase was replaced by new ones (hibonite, grossite, larnite), of which hibonite was present to the highest degree. Furthermore, in the case of low carbon alloy (0.042 wt% C), hibonite was not detected on the substrate surface contrary to chromium-doped corundum.
•Description of the high-temperature interaction at the Fe–C–O–Cr alloy/corundum interface by wettability testing.•Carbon content of alloy influences the redistribution of Ca and Si in corundum surface layer to a depth of around 20 μm.•When the carbon content is higher than 0.1 wt%, the primary corundum phase is replaced by hibonite, grossite and larnite.•Alloy composition affects the degree of interaction with high alumina substrate, which is considered one of the most stable.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
PDF
