Collaborative Model-based Systems Engineering using Dataspaces and SysML v2. - In: Systems, ISSN 2079-8954, Bd. 12 (2024), 1, 18, S. 1-22
Collaborative Model-based Systems Engineering between companies is becoming increasingly important. The utilization of the modeling possibilities of the standard language SysML v2 and the multilateral data exchange via Dataspaces open new possibilities for efficient collaboration. Based on systemic approaches, a modeling concept for decomposing the system into sub-systems is developed as a basis for the exchange. In addition, based on the analysis of collaboration processes in the context of Systems Engineering, an architectural approach with a SysML editor and Dataspace for the exchange is elaborated. The architecture is implemented on the basis of open-source solutions. The investigations are based on an application example from precision engineering. The potential and challenges are discussed.
https://doi.org/10.3390/systems12010018
Recent advances in ambient electrochemical methane conversion to oxygenates using metal oxide electrocatalysts. - In: Green chemistry, ISSN 1463-9270, Bd. 26 (2024), 2, S. 655-677
To reach a decarbonized future, the conversion of greenhouse gases into green fuels and valuable chemicals is of crucial importance. Methane emissions are the second most significant contributor to global warming. Recent advances in electrocatalytic partial oxidation of methane to high-value fuels at ambient temperatures promise to sidestep the requirement of high temperature in conventional thermal catalysis and provide a revolutionary, sustainable, and decentralized alternative to flaring. Electrocatalysts that can selectively produce valuable compounds from methane under mild conditions are essential for commercialization. This review covers current developments in the electrochemical partial oxidation of methane to oxygenates, with an emphasis on metal oxide electrocatalysts. The regularly deployed strategies, including doping and interface engineering, are systematically reviewed in detail. In addition, the design of the electrolytic cell, the electrolyte, time, potential, and temperature are examined thoroughly and discussed.
https://doi.org/10.1039/D3GC03513A
Antimetastatic lung cancer therapy using alkaloid Piperlongumine noncovalently bound to С60 fullerene. - In: Journal of drug delivery science and technology, Bd. 92 (2024), 105275, S. 1-10
A novel nanoformulation, C60 fullerene loaded with a plant alkaloid Piperlongumine (PL) molecules (C60-PL nanocomplex), as a potential drug for the treatment of highly metastatic lung cancer was created and characterized by using ultrasonic technology, computer simulation, atomic force and scanning tunneling microscopy. The aim of the study was to evaluate the antimetastatic potential of PL alone and the C60-PL nanocomplex using Lewis lung carcinoma (LLC) cell line as a model. Evidence has been obtained that the 2:1C60-PL nanocomplex is a potent agent capable of effectively reducing the survival, migration and invasion of LLC cells in vitro, as well as tumor growth and metastasis in vivo compared to free PL. These effects in cell behavior were shown to be associated with an increased Bax expression and high level of cleaved PARP confirming the proapototic potential of C60-PL nanocomplex as well as down-regulation of the mRNA of epithelial-mesenchymal transition regulator Twist1 and cancer stem cell marker CD44, a reduced level of phosphorylated mTOR and adaptor protein Ruk/CIN85. Histological analysis of the lung tissue of LLC-bearing mice showed that in animals that received the C60-PL nanocomplex, the regression of metastases prevailed over their growth. The obtained results allow to conclude that the proposed C60-PL nanocomplex represents a promising drug for the treatment of metastatic lung cancer.
https://doi.org/10.1016/j.jddst.2023.105275
Multi-strategy coordination enables WSe2 to achieve high-performance real-world detection of NO2. - In: Sensors and actuators, ISSN 0925-4005, Bd. 403 (2024), 135183, S. 1-10
In recent years, WSe2 has become an ideal material for room-temperature NO2 gas sensing, but its low response and long response time limit its application. In this study, we combined multiple strategies of constructing a three-dimensional structure, introducing Se vacancies, Au nanoparticle sensitization, and 1 T/2 H-phase modulation. The synergistic effect was utilized to effectively enhance the gas adsorption, charge transfer degree, and carrier transport capacity of WSe2 and achieve high-performance NO2 detection. The prepared V-WAAP achieved high response (78.32%) with a short response time (33 s), and outstanding stability and selectivity for low concentration (1 ppm) NO2. The intrinsic factors of sensing performance improvement were comprehensively analyzed by combining the results of compositional and structural characterization. In addition, we verified its potential for practical applications by assembling a V-WAAP-based NO2 gas sensing equipment.
https://doi.org/10.1016/j.snb.2023.135183
Structure-dependent oxidation behavior of Au-Cu nanoparticles. - In: Journal of alloys and compounds, ISSN 1873-4669, Bd. 976 (2024), 173179, S. 1-8
Thermal oxidation is an easily controlled method to change the physical and chemical properties of nanoparticles, thus optimizing and expanding their applications. Unfortunately, less attention has been paid to the role of the crystal structure whose atomic arrangements can be critical for oxidation. Au-Cu nanoparticles showing a fast order-disorder transformation are oxidized at two temperatures of ordered (L10) and disordered (A1) phase regions. The oxidation rates between the two phases are compared by the Arrhenius equation, and a lower oxidation rate is determined in the L10 lattice than in the A1 lattice based on the time required for the complete oxidation. One possible reason is attributed to the longer diffusion length in the L10 lattice compared to the A1 lattice due to the anisotropic diffusion path of the former while isotropic diffusion of the latter, resulting in longer oxidation time and then slower oxidation for the ordered sample. The crystalline phase of Au-Cu nanoparticles can be straightforwardly tuned and the resulting atomic disposition is a powerful tool to control oxidation evolution.
https://doi.org/10.1016/j.jallcom.2023.173179
Research progress of transition metal compounds as bifunctional catalysts for zinc-air batteries. - In: Nano research energy, ISSN 2790-8119, Bd. 3 (2024), 1, e9120092, S. 1-23
Zinc-air batteries (ZABs) are widely studied because of their high theoretical energy density, high battery voltage, environmental protection, and low price. However, the slow kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the air electrode limits the further application of ZABs, so that how to develop a cheap, efficient, and stable catalyst with bifunctional catalytic activity is the key to solving the development of ZABs. Transition metal compounds are widely used as cathode materials for ZABs due to their low cost, high electrocatalytic activity, and stable structure. This review summarizes the research progress of transition metal compounds as bifunctional catalysts for ZABs. The development history, operation principle, and mechanism of ORR and OER reactions are introduced first. The application and development of transition metal compounds as bifunctional catalysts for ZABs in recent years are systematically introduced, including transition metal oxides (TMOs), transition metal nitrides (TMNs), transition metal sulfides (TMSs), transition metal carbides (TMCs), transition metal phosphates (TMPs), and others. In addition, the shortcomings of transition metal compounds as bifunctional catalysts for ZABs were summarized and reasonable design strategies and improvement measures were put forward, aiming at providing a reference for the design and construction of high-performance ZABs cathode materials. Finally, the challenges and future in this field are discussed and prospected.
https://doi.org/10.26599/NRE.2023.9120092
Dissociation of singlet excitons dominates photocurrent improvement in high-efficiency non-fullerene organic solar cells. - In: Nano research energy, ISSN 2790-8119, Bd. 3 (2024), 1, e9120099, S. 1-8
In organic solar cells, the singlet and triplet excitons dissociate into free charge carriers with different mechanisms due to their opposite spin state. Therefore, the ratio of the singlet and triplet excitons directly affects the photocurrent. Many methods were used to optimize the performance of the low-efficiency solar cell by improving the ratio of triplet excitons, which shows a long diffusion length. Here we observed that in high-efficiency systems, the proportion of singlet excitons under linearly polarized light excitation is higher than that of circularly polarized light. Since the singlet charge transfer state has lower binding energy than the triplet state, it makes a significant contribution to the charge carrier generation and enhancement of the photocurrent. Further, the positive magnetic field effect reflects that singlet excitons dissociation plays a major role in the photocurrent, which is opposite to the case of low-efficiency devices where triplet excitons dominate the photocurrent.
https://doi.org/10.26599/NRE.2023.9120099
Complex material analysis of a TiC coating produced by hot pressing with optical light microscopy, EDS, XRD, GDOES and EBSD. - In: Surface and coatings technology, ISSN 1879-3347, Bd. 476 (2024), 130265, S. 1-11
The present study investigates the interface between carbon steel and titanium samples annealed at different temperatures (ϑ1 = Image 1 and ϑ2 = Image 2). In both cases, an observable layer forms at the interface, with its thickness increasing from tϑ1 = 2.75 ± Image 3 at Image 1 to tϑ2 = 8.86 ± Image 4 at Image 2. The layer's composition and thickness evolve with temperature. Analysis reveals approximately 40 at.-% carbon concentration in the exterior region, indicating likely titanium carbide creation. X-ray diffraction identifies titanium carbide peaks, while microscopy and elemental mapping confirm compositional gradients at the interface. Electron Backscatter Diffraction (EBSD) shows a gradient in grain size near the TiC surface, reflecting TiC nucleation rates. XRD data detect both titanium carbide and titanium phases, with TiC becoming more prominent at Image 2. Rietveld analysis further confirms TiC formation. Notably, distinct diffraction patterns on the contact and rear sides suggest a Ti(C, O, N) presence. Depth profiles exhibit varying surface and depth carbon concentrations, attributed to temperature effects. The study successfully demonstrates TiC coating fabrication through hot pressing, wherein Ti(C, O, N) coatings arise from titanium's affinity for reacting with oxygen and nitrogen. This research contributes to the understanding of phase transformations and interfacial properties in titanium-carbon steel systems.
https://doi.org/10.1016/j.surfcoat.2023.130265
Heat input control in horizontal lap joint welding through active wire preheating in GMAW-P. - In: Welding in the world, ISSN 1878-6669, Bd. 68 (2024), 4, S. 893-904
In gas metal arc welding (GMAW) the arc power, in general, increases when the wire feed speed is increased. Thus, controlling heat input into the workpiece becomes a challenge, especially when trying to increase productivity. Metal transfer modes such as pulsed and controlled short circuit have been successfully applied to allow smooth metal transfer with relatively low energy. The effect of increasing the electrified length of the electrode or decreasing wire diameter in reducing current has been known for years. However, to some extent, this effect is limited to the physical conditions when using a large distance from contact tip to workpiece. To further increase melting efficiency and reduce arc power the torch presented in this paper includes a second electric circuit into GMAW to preheat the wire by ohmic heating before it reaches the main circuit. In this context, the objective of this work was to verify the effects of active wire preheating in GMAW in lap joint case in terms of electric signal behavior, thermal behavior in the plate, and weld bead formation. By increasing the preheating current, significant reduction in arc power was achieved. This reflects on the resulting weld by avoiding molten pool sagging, reducing fused area, silicate formation, and backside oxidation. The reduction in heat input resulted finally in a smaller heat affected zone which had a finer microstructure. In conclusion, the use of active wire preheating in GMAW expands the potential for increasing productivity and controlling heat input into the workpiece.
https://doi.org/10.1007/s40194-023-01654-9
Application of novel constrained friction processing method to produce fine grained biomedical Mg-Zn-Ca alloy. - In: Journal of magnesium and alloys, ISSN 2213-9567, Bd. 12 (2024), 2, S. 516-529
In order to obtain Mg alloys with fine microstructures and high mechanical performances, a novel friction-based processing method, name as “constrained friction processing (CFP)”, was investigated. Via CFP, defect-free Mg-Zn-Ca rods with greatly refined grains and high mechanical properties were produced. Compared to the previous as-cast microstructure, the grain size was reduced from more than 1 mm to around 4 µm within 3 s by a single process cycle. The compressive yield strength was increased by 350% while the ultimate compressive strength by 53%. According to the established material flow behaviors by “tracer material”, the plastic material was transported by shear deformation. From the base material to the rod, the material experienced three stages, i.e. deformation by the tool, upward flow with additional tilt, followed by upward transportation. The microstructural evolution was revealed by “stop-action” technique. The microstructural development at regions adjacent to the rod is mainly controlled by twinning, dynamic recrystallization (DRX) as well as particle stimulated nucleation, while that within the rod is related to DRX combined with grain growth.
https://doi.org/10.1016/j.jma.2023.10.007