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Mg-3Ca alloys with varying Zn concentration (0 to 5 wt pct) were foamed using CaCO3via liquid processing route and their compressive and energy absorption behavior were investigated. The Mg-Zn-Ca alloy foams revealed a uniform cell structure with minimum defects and improved expansion in comparison to Mg-3Ca foams without zinc. The cell wall microstructure of Mg-3Ca alloy foam revealed micro-cracks and MgO particle agglomerates at the gas-solid interfaces. Upon Zn addition, the micro-cracks were diminished to larger extent and finely MgO particles were dispersed homogenously at the gas-solid interface. Pore diameter of the foams decreased from 2.29 to 2.06 mm, while circularity improved from 0.60 to 0.72 with increasing Zn content from 0 to 5 wt pct. The peak compressive stress also improved from 1.64 to 5.09 MPa with 5 wt pct Zn addition to Mg-3Ca foam. The ductility number improved from 0.66 to 0.75 while retaining energy absorption efficiency ~ 60 pct in the plateau region. The improved mechanical properties of Mg-Zn-Ca foams are due to elimination of brittle Mg2Ca and increase in the Mg6Zn3Ca2. The reduced pore diameter, circular and equiaxed pores and crack-free interfaces in the foams were also contributed to the better mechanical properties. [ABSTRACT FROM AUTHOR]

The quality of crushing, power consumption, and discharging performance of a straw crusher are greatly influenced by the characteristics of its internal flow field. To enhance the straw crusher's flow field properties and improve the efficiency with which crushed material is discharged, first, the main structural parameters influencing the air flow in the crusher are discussed. Then, the coupled gas-solid flow field in the straw crusher is numerically calculated through solution of the Navier-Stokes equations and application of the discrete element method (DEM). Finally, the discharge performance index of the crusher is examined through detailed analysis of the crushed material dynamics. Additionally, a multi-island genetic algorithm is used to optimize the structure and operational factors that have significant effects on the discharge performance. With optimization, the accumulation rate of crushed materials in the bottom region of the straw crusher decreases by 20.08%, and the mass flow rate at the discharge outlet increases by 11.63%. [ABSTRACT FROM AUTHOR]

The document from Chemical Communications, published in 2024, provides a comprehensive list of articles covering various topics in chemistry. It includes research on electrochemical deconstructive functionalization, organoboron catalysis, recent progress in sensing technologies, and advancements in metal carbene-induced rearrangements. The journal aims to uncover new possibilities through original discoveries and fundamental questions in the field of chemistry. [Extracted from the article]

[Display omitted] • Designed a novel multifunctional CuTCPP/MXene/TiO 2 catalyst by crystal plane regulation and hydrogen bonding. • Developed a system for atmospheric CO 2 capture and in-situ conversion at the gas-solid interface. • There is no need to add any sacrificial agent and alkaline absorbent in the reaction system. • The catalyst demonstrated excellent CO 2 conversion rates, effectively producing CO and CH 4. Directly capturing atmospheric CO 2 and converting it into valuable fuel through photothermal synergy is an effective way to mitigate the greenhouse effect. This study developed a gas–solid interface photothermal catalytic system for atmospheric CO 2 reduction, utilizing the innovative photothermal catalyst (Cu porphyrin) CuTCPP/MXene/TiO 2. The catalyst demonstrated a photothermal catalytic performance of 124 μmol·g−1·h−1 for CO and 106 μmol·g−1·h−1 for CH 4 , significantly outperforming individual components. Density functional theory (DFT) results indicate that the enhanced catalytic performance is attributed to the internal electric field between the components, which significantly enhances carrier utilization. The introduction of CuTCPP reduces free energy of the photothermal catalytic reaction. Additionally, the local surface plasmon resonance (LSPR) effect and high-speed electron transfer properties of MXene further boost the catalytic reaction rate. This well-designed catalyst and catalytic system offer a simple method for capturing atmospheric CO 2 and converting it in-situ through photothermal catalysis. [ABSTRACT FROM AUTHOR]

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In-situ texturing hollow carbon host by gas–solid interface reaction with high pore volume and Fe single atoms doping ensures the excellent cycling performance of HCS-Fe/Se cathode due to its accelerating solid-phase redox kinetics. [Display omitted] • In-situ texturing hollow carbon sphere by one-step reaction between SiO 2 and PTFE. • H 2 SeO 3 is an ideal Se resource for homogeneous Se-based cathode. • DRT analyses verify the solid-phase conversion mechanism of HCS-Fe/Se. • Excellent performances realized due to electrocatalytic effect of Fe single atoms. Se-based cathodes have caught tremendous attention owing to their comparable volumetric capacity and better electronic conductivity to S cathodes. However, its low utilization ratio and sluggish redox kinetics due to the high reaction barrier of solid-phase transformation from Se to Li 2 Se limit its practical application. Herein, an in-situ texturing hollow carbon host by gas–solid interface reaction anchored with Fe single-atomic catalyst is designed and prepared for advanced Li-Se batteries. This Se host presents high pore volume of 1.49 cm3 g−1, Fe single atom content of 1.53 wt%, and its specific structure protects single-atomic catalyst from the destructive reaction environment, thus balancing catalytic activity and durability. After Se loading by reduction of H 2 SeO 3 , this homogenous Se-based cathode delivers a superior rate capacity of 431.3 mA h g−1 at 4C, and great discharge capacity of 301.8 mA h g−1 after 1000 cycles at 10C, with high Li-ion diffusion coefficient and capacitance-contributed ratio. The distribution of relaxation times analysis verifies solid-phase transformation mechanism of this cathode and density functional theory calculations confirm the adsorption and bidirectionally catalysis effect of Fe single-atomic catalyst. This work provides a new strategy to prepare high-efficient Se cathode associated with non-noble metal single atoms for high-performance Li-Se batteries. [ABSTRACT FROM AUTHOR]

In this study, the motion of wet particles in the drying unit of a vertical powder dryer is investigated by using a Discrete element method (DEM) coupled with a liquid bridge force. In particular, by varying parameters such as the particle mass flow rates, the superficial gas velocities, and superficial gas temperatures, the influence of the moisture content on the flow behavior is examined. The results show that when the moisture content increases, the mean particle velocity decreases while the bed mean solid "holdup" and the mean residence time (MRT) of particles grow. It is also found that the local solid holdup is relatively higher in the near-wall region and decreases towards the near-fluid region. Two regression models are introduced accordingly for the mean particle velocity and the bed mean solid holdup by means of the RSM-BBD (Response surface methodology-Box-Behnken design) method to obtain the optimal combination of parameters for flooding prevention. Finally, the optimal results are compared with numerical observations. As the relative error is less than 10%, this demonstrates that the proposed methodology can accurately describe the particle flow dynamics in the drying unit. Graphic Abstract [ABSTRACT FROM AUTHOR]

[Display omitted] • CuTCPP was innovatively anchored on the surface of 2D anatase TiO 2 ultrathin nanosheets. • Taking low concentration CO 2 in ambient air as the research object, a photocatalytic integrated system for CO 2 capture and in-situ conversion was constructed. • CO 2 reduction conversion is achieved at the gas-solid interface. The practical application of photocatalytic reduction of CO 2 system becomes possible. • There is no need to add any sacrificial agent and alkaline absorbent in the reaction system. • This catalytic system can achieve stable, efficient and highly selective conversion. (CO 2 → CO). Directly capturing CO 2 in ambient air and converting it into value-added fuels using photocatalysis is a potentially valuable technology. In this study, Cu-porphyrin (tetrakis-carboxyphenyl porphyrin copper, CuTCPP) was innovatively anchored on the surface of TiO 2 (titanium dioxide) nanosheets to form an S-scheme heterojunction. Based on this, a photocatalytic reaction system for stably converting CO 2 in ambient air into value-added fuels at the gas–solid interface was constructed without addition of sacrificial agents and alkaline liquids. Under the illumination of visible light and sunlight, the evolution rate of CO is 56 μmol·g−1·h−1 and 73 μmol·g−1·h−1, respectively, with a potential CO 2 conversion rate of 35.8 % and 50.4 %. The enhanced of photocatalytic performance is attributed to the introduction of CuTCPP, which provides additional active sites, significantly improves capture capacity of CO 2 and the utilization of electrons. Additionally, the formation of S-scheme heterojunction expands the redox range and improves the separation efficiency of photo-generated charges. [ABSTRACT FROM AUTHOR]

The direct conversion of atmospheric CO2 into fuel via photocatalysis exhibits significant practical application value in advancing the carbon cycle. In this study, we established an electro-assisted photocatalytic system with dual compartments and interfaces, and coated Ag nanoparticles on the titanium nanotube arrays (TNTAs) by polydopamine modification. In the absence of sacrificial agent and alkali absorption liquid conditions, the stable, efficient and highly selective conversion of CO2 to CO at the gas-solid interface in ambient air was realized by photoelectric synergy. Specifically, with the assistance of potential, the CO formation rates reached 194.9 µmol h-1 m-2 and 103.9 µmol h-1 m-2 under ultraviolet and visible light irradiation, respectively; the corresponding CO2 conversion rates in ambient air were 30% and 16%, respectively. The excellent catalytic effect is mainly attributed to the formation of P-N heterojunction during the catalytic process and the surface plasmon resonance effect. Additionally, the introduction of solid agar electrolytes effectively inhibits the hydrogen evolution reaction and improves the electron utilization rate. This system promotes the development of photocatalytic technology for practical applications and provides new insights and support for the carbon cycle. [ABSTRACT FROM AUTHOR]

Long-term operation of high voltage direct current at elevated temperatures can result in the accumulation of surface charges in DC gas-insulated transmission line (GIL) insulators. Such a phenomenon leads to localized electric field distortion, increasing the risk of surface discharge. The analysis of interaction behaviors between surface charge and space charge at interfacial domains of GIL insulators is a complex task, which requires a comprehensive understanding of physical mechanisms of the gas–solid interface charging. In this work, a two-dimensional bipolar charge transport and interaction (2D BCTI) model is established, with the consideration of both surface and space charge dynamics. Pulsed electroacoustic tests and surface potential measurements are conducted on DC GIL insulator materials under different electrical-thermal coupling conditions. Experimental results exhibit great consistency with the predictions from the 2D BCTI model. The local accumulation of space charge near interfaces has certain effects on surface potential distribution, which in turn influences charge injection behavior from electrodes. In comparison to traditional surface charge simulation models, the consideration of space charge–surface charge interaction behaviors proves to be essential for estimating the polarity and amplitude of surface potential distribution. This model holds promise for assessing charge characteristics in electrical equipment where direct measurement is challenging. [ABSTRACT FROM AUTHOR]

Charge accumulation usually happens on the surface of spacers under DC operation, which is susceptible to inducing surface flashover. In order to explore the surface charge accumulation mechanisms and the influences of dielectric conductivity, gas ion mobility, and temperature field on the surface charges, a time-varying charge density model at the gas–solid interface of spacers was established. The results of the simulation show that the discontinuity of the current density between the spacer bulk side and the gas ion flow is the fundamental reason for the charge accumulation on the spacer surface. Additionally, the value of current density fluxes at the interface continues to decrease with the change of the electric field, and the progress of charge transfer gradually stabilizes. Moreover, the dielectric conductivity directly affects the charge accumulation process, and there is a critical conductivity in which the effect of charge conduction in dielectrics counteracts that of gas-phase charge deposition, theoretically. When the conductivity is higher than the critical conductivity, the solid-side charge conduction is the main source of the surface charge accumulation, while the gas-phase charge deposition on the gas side plays a dominant role when the conductivity is lower than the critical conductivity. The charge accumulation is not significantly affected by gas ion mobility when the temperature is evenly distributed. However, under the temperature field with gradient distribution, the current density fluxes at the interface change, causing the polarity reverse of the accumulated charge. In the high-temperature region, the volume current density surges simultaneously with the conductivity, leading to a higher density of surface charge accumulation. Lastly, the design of spacers needs to keep the current densities on both sides of the interface as similar as possible in order to avoid excessive charge gathering in localized areas. [ABSTRACT FROM AUTHOR]

The proliferation of urbanization and the integration of new energy sources have stimulated the development of gas-insulated transmission lines and switchgear (GIL/GIS). In particular, the compact DC GIS in offshore converter platforms will significantly reduce footprints for DC switchyards, exhibit exceptional climatic resistance, and facilitate the cost-effective connection of remote offshore wind farms and submarine links. Nevertheless, insulators used in GIS/GIL always suffer from surface charge accumulation under DC stress, which could distort and enhance the local electric field and thus trigger a flashover at the gas–solid interface if it exceeds certain magnitude levels. This susceptibility becomes a major concern affecting the reliability of DC gas-insulated systems. Beyond these engineering-related challenges lie fundamental physics problems involving mechanisms of charge accumulation and charge-induced flashover which still require exploration. To this end, this paper presents an overview of recent advancements on this topic whilst highlighting relevant issues to be addressed. Specifically, the surface charge accumulation phenomena under DC fields are reviewed, and the charging mechanisms are summarized from macroscopic to microscopic perspectives. Further, the correlation between surface charge and surface flashover is discussed. Moreover, recent developments in tailoring methods for surface charging are also presented. Finally, perspectives are given on current research progress and future needs. [ABSTRACT FROM AUTHOR]

Electrochemical methods have been widely used to remove gaseous pollutants that are dissolved in liquids. However, there have been no significant attempt made to remove gaseous pollutants in their gas state, especially through electrochemical method. In this study, we attempted to remove gaseous acetaldehyde (AA) through electro-oxidation using an Ag-Hg bimetallic catalyst coated on a Ni foam electrode at a gas–solid interface. The interface was induced by a semi-solid agar gel in a membrane-divided electrolytic cell. We confirmed the formation of Ag-Hg on the Ni foam electrode through X-ray photoelectron spectroscopy and scanning electron microscopy. We also found that the semi-solid gel was a suitable solid electrolyte, as evidenced by the absence of discernible redox peaks in cyclic voltammetry analysis and the high charge transfer resistance in electrochemical impedance analysis. Under inlet conditions of 15 ppm with a flow rate of 200 mL min−1, we could achieve up to 80% AA degradation. This was due to the effective transfer of electrons in the presence of the semi-solid gel, which was eight times higher than that obtained in the zero-gap method. In continuous operation of the electrochemical reactor with a single-pass of AA, we consistently achieved a removal capacity of 169.81 mg cm−2 h−1 over a 1-h period in an Ar atmosphere. These results demonstrate the practical applicability of this electrochemical system developed using a liquid-free electrolyte and a bimetallic catalyst for the electrode. [ABSTRACT FROM AUTHOR]

A hydrogen diffusion model was developed, which accounts realistically for the kinetics of hydrogen adsorption, absorption and their reverse processes at the gas-solid interface. Using the model, the hydrogen distribution at the fatigue crack tip of austenitic stainless steels (304, 316 L) in internal and external hydrogen tests were analyzed. Results indicate that for stable austenitic stainless steel, the hydrogen concentration at the fatigue crack tip is much higher in internal hydrogen test than that in external hydrogen test, which is attributed to the extremely low adsorption, desorption and diffusion rates of γ phase. For metastable austenitic stainless steel, hydrogen rapidly enters into strain-induced α′ martensite around the fatigue crack tip, forming an enrichment peak at the α′/γ interface in external hydrogen test. While significant hydrogen outgassing occurs in α′ phase in internal hydrogen test, leading to a much lower crack tip concentration compared with external hydrogen test. • A hydrogen diffusion model combined with hydrogen gas uptake kinetics was proposed. • The hydrogen distributions at the crack tip of 316 and 304 steels were analyzed. • The strain-induced martensitic transformation was considered in modeling. • The difference in FCG rates of internal and external hydrogen tests was elucidated. [ABSTRACT FROM AUTHOR]

Industrial lignin, a by-product of pulping for papermaking fibers or of second-generation ethanol production, is primarily served as a low-grade combustible energy source. The fabrication of high-value-added functional materials with industrial lignin is still a challenge. Herein, a three-dimensional hierarchical lignin-derived porous carbon (HLPC) was prepared with lignosulfonate as the carbon source and MgCO3 as the template. The uniform mixing of precursor and template agent resulted in the construction of a three-dimensional hierarchical porous structure. HLPC presented excellent electromagnetic wave (EMW) absorption performance. With a low filler content of 7 wt%, HLPC showed a minimum reflection loss (RL) value of −41.8 dB (1.7 mm, 13.8 GHz), and a maximum effective absorption bandwidth (EAB) of 4.53 GHz (1.6 mm). In addition, the enhancement mechanism of HLPC for EMW absorption was also explored through comparing the morphology and electromagnetic parameters of lignin-derived carbon (LC) and lignin-derived porous carbon (LPC). The three-dimensional hierarchical porous structure endowed the carbon with a high pore volume, resulting in an abundant gas–solid interface between air and carbon for interfacial polarization. This structure also provided conductive networks for conduction loss. This work offers a strategy to synthesize biomass-based carbon for high-performance EMW absorption. [ABSTRACT FROM AUTHOR]

Melatonin is a potent defensive molecule against oxidative damage. The knowledge of the interaction between melatonin and reactive oxygen species (ROS) is important for understanding antioxidant mechanisms. However, direct observation of reaction products of melatonin with ozone (a reactive oxygen species) in vitro is absent. In this paper, a simple and rapid method using a laser-induced acoustic desorption time-of-flight mass spectrometer (LIAD-TOFMS) is reported to characterize the reaction products of melatonin with ozone at the gas-solid interface. The advantage of this approach is the direct analysis of the products without secondary treatment. A series of oxidation products were observed, including primary hydroxymelatonin (HO-MLT), N1-acetyl-N2-formyl-5-methoxykynurenin (AFMK), and secondary (N1-acetyl-5-methoxykynurenin, AMK). Another significant finding is two pathways for the reaction of melatonin with ozone in vitro. These results demonstrate a novel strategy for the direct determination of reaction products at the gas-solid interface. [ABSTRACT FROM AUTHOR]

In this work, the impedance spectroscopy (IS) technique was used to aid in understanding the reaction mechanism of the CO oxidation reaction using the Pr2Zr2−xFexO7±δ (x = 0 and 0.10) mixed oxide as a heterogeneous catalyst. The catalytic reaction occurred in the same temperature range where there was a decrease in the overall resistivity of the materials. Moreover, it has been observed that within the temperature range where the catalytic process takes place, there is a variation in the A and n parameters of the power law dispersion. Combining IS with catalytic reactions offers a robust approach to enhance the understanding of the mechanisms involved in the CO oxidation reaction. It enables precise analysis of the changes that take place at the solid–gas interface, particularly the generation of reactive oxygen species. Furthermore, it allows examining the relationship between the presence of oxygen vacancies and defects, which directly impact the catalytic process. [ABSTRACT FROM AUTHOR]

Dielectric barrier discharge (DBD), a non-thermal plasma technology, has a wide range of environmental applications. In this study, TiO2, SiO2, and Al2O3 were coated on the surface of a quartz dielectric using a dip-coating method. The catalyst coating coatings effectively improved the local discharge intensity, thus enhancing the generation of reactive species. After discharge by the DBD system, the O atom in the middle of TiO2 crystal is replaced by N atom doping, and the Al = O and Al OH groups on the surface of Al2O3 increase. All Catalyst coating surfaces contained a small number of hydroxyl groups. TiO2 and Al2O3 surfaces had fewer oxygen vacancies. thus making O3 synthesis dominant at the gas–solid interface. [ABSTRACT FROM AUTHOR]

Systematic optimization of the photocatalyst and investigation of the role of each component is important to maximizing catalytic activity and comprehending the photocatalytic conversion of CO2 reduction to solar fuels. A surface‐modified Ag@Ru‐P25 photocatalyst with H2O2 treatment was designed in this study to convert CO2 and H2O vapor into highly selective CH4. Ru doping followed by Ag nanoparticles (NPs) cocatalyst deposition on P25 (TiO2) enhances visible light absorption and charge separation, whereas H2O2 treatment modifies the surface of the photocatalyst with hydroxyl (–OH) groups and promotes CO2 adsorption. High‐resonance transmission electron microscopy, X‐ray photoelectron spectroscopy, X‐ray absorption near‐edge structure, and extended X‐ray absorption fine structure techniques were used to analyze the surface and chemical composition of the photocatalyst, while thermogravimetric analysis, CO2 adsorption isotherm, and temperature programmed desorption study were performed to examine the significance of H2O2 treatment in increasing CO2 reduction activity. The optimized Ag1.0@Ru1.0‐P25 photocatalyst performed excellent CO2 reduction activity into CO, CH4, and C2H6 with a ~95% selectivity of CH4, where the activity was ~135 times higher than that of pristine TiO2 (P25). For the first time, this work explored the effect of H2O2 treatment on the photocatalyst that dramatically increases CO2 reduction activity. [ABSTRACT FROM AUTHOR]

To date, numerical simulation techniques for surface flashover are still under development. In this work, a DC surface flashover numerical simulation model is constructed based on a gas–solid coupling surface flashover theoretical model with a multilayered structure at the gas–solid interface. Considering the effects of solid, gas, and gas–solid interaction on surface flashover, bipolar charge transport in the solid surface layer, collision ionization in the gas phase layer, secondary electron emission, and gas adsorption in the gas surface layer are combined to calculate the surface flashover voltage. By initializing model parameters, surface charge transport dependent dc surface flashover voltages of epoxy composites in compressed nitrogen are calculated. The results indicate that the surface flashover voltage increases with surface deep trap level, deep trap density, shallow trap density, and carrier mobility; however, surface flashover voltage decreases with surface shallow trap level and surface charge density. To further investigate the effects of surface trap on surface flashover, a "U-shaped" curve is constructed to describe the relationship between surface flashover voltage and surface trap level by the simulation method which shows good agreement with experimental results. The simulation indicates surface flashover voltage of epoxy composites is influenced by surface deep and shallow traps in the solid surface layer—shallow traps mainly influence surface charge dissipation, while deep traps mainly influence electron emission on the solid surface. The value of Ptr/Pde is crucial for the dominating surface trap in surface flashover. [ABSTRACT FROM AUTHOR]

This review examines the significance of the zeta adsorption model in physics and its integration with statistical mechanics within the field of interface adsorption. Through a comprehensive analysis of existing research, this study presents the collective findings and insights derived from the reviewed literature. The zeta adsorption model, proposed by Ward, has gained recognition for its seamless extension into the thermal disequilibrium region without encountering singularities. By incorporating principles from quantum mechanics and statistical thermodynamics, this model offers fresh perspectives on the adsorption of gas molecules on solid surfaces. Notably, it demonstrates enhanced accuracy in describing the adsorption performance of mesoporous materials and nanomaterial surfaces, surpassing the limitations of traditional models such as the BET isotherm. Additionally, this review explores the behavior of cluster formation under varying temperature and pressure conditions. It highlights the correlation between increasing pressure ratios and the decreased availability of empty adsorption sites, resulting in the formation of larger clusters within the adsorbate. Ultimately, this process leads to a transition from adsorption to condensation, where the liquid phase wets the solid surface. Moreover, the zeta adsorption model provides a solid theoretical foundation for understanding crucial aspects of gas-solid interface adsorption. It enables the determination of the distribution of adsorbate clusters on gas-solid interfaces, facilitates the identification of wetting pressure ratios during phase transitions, and allows for the calculation of solid surface tension under conditions of zero adsorption. Noteworthy parameters such as the bonding strength (β) between the solid surface and adsorbed atoms significantly influence the overall strength of the solid-fluid interaction. Furthermore, the phenomenon of surface subcooling, which necessitates sufficient energy for the transformation from adsorbed vapor to condensate liquid, plays a pivotal role in studying interface phase transitions. Additionally, this review investigates the thermodynamic stability of the adsorbate through an analysis of molar latent heat. It reveals that beyond a critical adsorbate coverage, the formation of critical-sized clusters and the ensuing interactions among these components render the adsorbate unstable. This instability prompts a transition from the interface to a liquid phase, followed by subsequent adsorption onto the surface. In summary, this literature review highlights the significant contributions of the zeta adsorption model to the field of physics, particularly in the context of interface adsorption. It serves as a valuable tool for studying various materials and cluster formation, thanks to its seamless extension into the thermal disequilibrium region and its incorporation of principles from quantum mechanics and statistical thermodynamics. By presenting a synthesis of existing research, this review sheds light on the advantages of the zeta adsorption model and paves the way for further investigations into gas-solid interface adsorption phenomena. [ABSTRACT FROM AUTHOR]

Due to their superior mechanical and electrical characteristics, Al2O3 epoxy composites (Al2O3/EP) are extensively utilized in producing insulation devices. However, Al2O3/EP is prone to accumulating a large amount of charge under a direct current (DC), which threatens the operation of the power system. In this article, we conducted surface fluorinated etching and SiOx deposition on the material by atmospheric pressure plasma jet (APPJ). Various testing methods were used to investigate the impacts of plasma modification on the physicochemical characterization of Al2O3/EP, and the changes in superficial conductivity, flashover voltage, charge dissipation rate, and trap distribution were experimentally tested. The influences of two plasma modification methods on the physicochemical characterization of Al2O3/EP were analyzed. The enhancement mechanism of Al2O3/EP flash behavior by fluorinated etching and SiOx deposition is summarized. The findings demonstrate that the insulation behavior of Al2O3/EP results from a combination of a few dominant and multiple factors. Fluorinated etching enhances the degree of roughness and the relative proportion of the F element, provides chemically deep traps, and raises the flashover voltage by up to 19%. SiOx deposition boosts the dispersion of charges by forming SiOx layers on the surface, reducing the degree of roughness and increasing the content of the silicon–oxygen element, making it more difficult for charges to accumulate and increasing the flashover voltage by up to 15%. This study will reveal the internal relationship between gas–solid interface and surface flashover, and provide a possible scheme for suppressing surface flashover. Highlights: Modifications substantially increase the flashover voltage.Modifications allow a wide range of interface parameters to be adjusted.The effects of modifications on physicochemical properties are compared.The enhancement mechanism of flashover voltage by modifications is compared.The overall effect of multiple factors on insulation properties is analyzed. [ABSTRACT FROM AUTHOR]

Context: SF6 gas has a strong greenhouse effect, and how to treat SF6 in an environmentally friendly way has been a hot topic of current research. In this paper, the adsorption behavior of SF6 on the surface of Pd-doped hydroxyl-terminated modified Ti3C2Tx (i.e., Ti3C2(OH)2) was investigated based on the density functional theory using two-dimensional MXene as the catalyst. The structures of different Pd-doped Ti3C2(OH)2 were analyzed and the most structurally stable doped structures were selected as the basis for subsequent calculations. A large number of adsorption configurations were constructed and geometrically optimized, and the adsorption energy, charge transfer, differential charge density, and density of states of the systems were calculated in order to analyze the gas–solid interactions and find the surface active sites; compared with the adsorption performance of undoped Ti3C2(OH)2 on SF6, it was found that Pd doping played a less inhibitory role in the adsorption of SF6 on the Ti3C2(OH)2 surface. The results of this study can provide theoretical support for the use of Pd-doped Ti3C2(OH)2 as a catalyst for the degradation of SF6. Methods: In this paper, simulations of SF6 adsorption on Ti3C2Tx surfaces are based on density functional theory and are carried out in the Dmol3 module of Material Studio. To better describe the non-uniform electron density of the actual system, the PBE functional in the generalized gradient approximation (GGA) was chosen for the optimization of the structure of the gas–solid interface system and the calculation of the relevant electronic properties, combined with the Grimme dispersion correction in the DFT-D dispersion correction for the electron exchange correlation term. Because both Pd and Ti are transition metal elements, the mode-conserving pseudopotential DNP basis set containing relativistic effects was chosen for the electronic wave function expansion. In this paper, an all-electron model is used for the inner core treatment of gas molecules and a density generalized semi-nuclear pseudopotential DSSP is used for the solid surface treatment. [ABSTRACT FROM AUTHOR]

A low concentration of Te4+ doping is found to be capable of endowing the lead-free Cs2SnCl6 perovskites with excellent photoluminescence quantum yield (PLQY), while further increasing Te4+ concentration leads to PLQY deterioration. The mechanism behind the improved PLQY is intensively studied and reported elsewhere. However, little work is conducted to understand the decreased PLQY at high doping levels and to explore its implications for non-PL-related applications. Here, it is demonstrated that the Te4+-incorporated Cs2SnCl6 can be promising candidate for efficient CO2 photocatalysis. An optimum photocatalytic performance is achieved when Te4+ concentration reaches as high as 50%, at which point significant PL quenching has occurred. Through a detailed spectral characterization, such concentration-dependent functionality is attributed to systematic changes in both electronic and local crystal structure, which allow a robust regulation of excitation energy relaxation channels. These findings expand the scope of available photocatalysts for CO2 reduction and also inform synthetic planning for the preparation of multifunctional Pb-free metal halide perovskites. [ABSTRACT FROM AUTHOR]

We propose an innovative and scalable NH 4 Cl-assisted gas–solid interface reaction treatment technique, where NH 4 Cl thermally decomposes to HCl and NH 3 gas at 350 °C. In situ construction of oxygen vacancies and spinel phase structures on the surface of LMOs by reaction with HCl and NH 3 gas. The synergistic effect of oxygen vacancies and surface spinel phases can not only effectively enhance the redox properties of oxygen ions and inhibit irreversible oxygen release, but also effectively mitigate side reactions at the electrode/electrolyte interface, stabilize the layered structure and enhance the Li+ diffusion rate. [Display omitted] • An innovative and scalable NH 4 Cl-assisted gas–solid interface reaction treatment technique is proposed for the simultaneous construction of oxygen vacancies and surface spinel phases on LMOs. • The surface spinel phase structure not only improves the stability and reduces the side effects of the interface, but also effectively improves the Li+ diffusion kinetics. • The pre-constructed oxygen vacancy increases the state density of the O-2p orbital near the Fermi level and increases the energy of oxygen vacancy formation, thus enhancing the redox of oxygen ions and reducing the irreversible release of O 2. Li-rich Mn-based oxide cathodes (LMOs) are regarded as one of the most prospective high energy density cathodes due to the reversible anion redox reaction, which gives them a very high capacity. However, LMOs materials usually have problems like low initial coulombic efficiency (ICE) and poor cycling performance during cycling, which are associated with irreversible surface O 2 release and unfavourable electrode/electrolyte interface side reactions. Herein, an innovative and scalable NH 4 Cl-assisted gas–solid interfacial reaction treatment technique is employed to construct oxygen vacancies and spinel/layered heterostructures simultaneously on the surface of LMOs. The synergistic effect of the oxygen vacancy and the surface spinel phase can not only effectively enhance the redox properties of the oxygen anion and inhibit irreversible oxygen release, but also effectively mitigate the side reactions at the electrode/electrolyte interface, inhibit the formation of CEI films and stabilize the layered structure. The electrochemical performance of the treated NC-10 sample improved significantly, showing an increase in ICE from 77.4 % to 94.3 % and excellent rate capability and cycling stability, with a capacity retention of 77.9 % after 400 cycles at 1 C. This oxygen vacancy and spinel phase integration strategy offers an exciting prospect and avenue for improving the integrated electrochemical performance of LMOs. [ABSTRACT FROM AUTHOR]

Nanostructured materials with high aspect ratios have been widely studied for their unique properties. In particular, nanosheets have safety, dispersibility, and nanosized effects, and nanosheets with exceptionally small thicknesses exhibit unique properties. For non‐exfoliable materials, the bottom‐up nanosheet growth using various interfaces as templates have been investigated. This review article presents the synthesis of nanosheets at the interfaces and layered structure; it explains the features of each interface type, its advantages, and its uniqueness. The interfaces work as templates for nanosheet synthesis. We can easily use the liquid‐liquid and gas‐liquid interfaces as the templates; however, the thickness of nanosheets usually becomes thick because it allows materials to grow in thickness. The solid‐gas and solid‐liquid interfaces can prevent nanosheets from growing in thickness. However, the removal of template solids is required after the synthesis. The layered structures of various materials provide two‐dimensional reaction fields between the layers. These methods have high versatility, and the nanosheets synthesized by these methods are thin. Finally, this review examines the key challenges and opportunities associated with scalable nanosheet synthesis methods for industrial production. [ABSTRACT FROM AUTHOR]

Recent study has found excellent bulk and surface insulation property of Si 3 N 4 ceramic which make it potential to serve as key insulation component in various energy transmission apparatus. Charge accumulation at gas-solid interface is a critical insulation property but few relevant study on Si 3 N 4 can be found. This contribution has investigated the surface charge property of Si 3 N 4 ceramic compared to traditional insulation polymer under different electrical-thermal stress. Through its comparison with the electric field distribution, the main source of the surface charge accumulation is analyzed, indicating that the superior surface charge suppression performance of Si 3 N 4 lies on its low carrier density and conduction barrier, which considerably prevent charge injection and suppress the normal electric field which drives the charge to the gas-solid interface. The proposed mechanism is also validated by the characterization on conducting and space charge property for Si 3 N 4 as well as dynamic simulation on surface charge accumulation. [ABSTRACT FROM AUTHOR]

A molecular-level understanding of CO adsorption behavior would be greatly beneficial to resolving the problem of CO poisoning in fuel cells and medical science. Herein, an efficient borrowing strategy based on surface enhanced Raman scattering (SERS) has been developed to investigate the adsorption behavior of CO at the gas–solid interface. A composite SERS substrate with high uniformity was fabricated by electrochemical deposition of optimal Pt over-layers onto an Au nanoparticle film. The results indicated that the linearly bonded mode follows the Langmuir adsorption curve (type I), while the multiply bonded did not. It took a longer time for the C–OM vibration to reach the adsorption equilibrium than that of C–OL. The variation tendency toward the Pt–COL frequency was in opposition to that of C–OL, caused by the chemical and dipole–dipole coupling effects. The increase in dynamic coupling effects of the CO molecules caused a blue shift in νCO and a red shift of the Pt–CO band, while its shielding effect on SERS intensity cannot be ignored. Additionally, higher pressure is more conducive for linear adsorption to achieve saturation. Density functional theory calculations were employed to explore the adsorption mechanisms. It should also be noted that the substrate with good recycling performance greatly expands its practical application value. The present study suggested that the SERS-based borrowing strategy shows sufficient even valuable capacity to investigate gas adsorption kinetics behavior. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of the oxidation of Cu thin films in the low-temperature regime is of fundamental interest and particularly relevant for applications in the fields of micro- and nanoelectronics, sensors, catalysis, and solar cells. The current study reports on the oxidation kinetics of PVD grown Cu thin films (20–150 nm thick) and the oxide phase evolution from Cu2O to CuO upon thermal oxidation in the temperature range of 100–450 °C. XRD investigations in the laboratory and at the synchrotron show that the oxide phase formation critically depends on the oxidation conditions such as temperature and oxygen partial pressure. The real-time synchrotron XRD measurements reveal that the formation of the CuO phase only starts after complete oxidation of the Cu films to Cu2O films. In situ resistance measurements were performed to follow the oxide growth rate of Cu2O on Cu films in the temperature range of 100–300 °C in air and in 10 mbar pO2. It is found that the oxidation kinetics of Cu films to Cu2O films follows the linear rate law, which is attributed to surface reaction controlled oxidation. The oxygen dissociation rate at the gas–solid interface is the rate-limiting process. A dramatic decrease in the linear oxidation rate is observed at low oxygen partial pressures. The fundamental differences between the oxidation rate-limiting processes of Cu as compared to other transition metal films are discussed. [ABSTRACT FROM AUTHOR]

The interfacial free energy $ \gamma $, (between solid-gas, solid-liquid or liquid-gas interfaces) plays a critical role in many physical and chemical processes involving material surfaces. Due to experimental difficulties in measuring $ \gamma $ various alternative theoretical or computational approaches have been suggested to date. However, despite being commonly used in interface modeling, phase fields models have not been fully exploited for addressing the question of anisotropy in $ \gamma $. In this work we propose phase field methodologies that use real parameters to directly obtain $ \gamma $ and its anisotropy. The approach is successfully applied to Lennard-Jones system for liquid-gas and solid-gas interfaces. In particular, a novel discrete version of phase field method is introduced for modeling of the solid-gas interfaces of Lennard-Jones systems on the actual fcc lattice. The approach provides a methodology to understand the process of transfer of microscopic anisotropy to the macroscopic scale. Interfacial free energy, $ \gamma $, is calculated at multiple different conditions (including the triple point) for different orientations. Results show that $ \gamma $ is larger in the [100] direction than [110] direction by several percent. The results are compared with the literature. [ABSTRACT FROM AUTHOR]

In this study, various kinds of wave solutions corresponding to the conformable time-fractional Biswas–Milovic model have been obtained via the new extended direct algebraic method. The proposed approach has been used to obtain rogue wave, breather, damped wave solutions. The new extended direct algebraic method provides 37 types of soliton solution which covers almost all types of soliton families. The exact solution of the Biswas–Milovic equation can provide insights into the physical and chemical properties of the gas-solid interface. By analyzing the parameters of the equation, such as the Langmuir-Freundlich coefficient and the heterogeneity factor, researchers can gain a better understanding of the nature of the adsorption process and the properties of the porous solid. The propagation of the wave soliton possessing distinctive physical characteristics is graphically presented in 3-D plots and the dependence of the behavior of the solutions on the fractional derivative has also been analyzed which provides us with an insight into the study of wave propagation in a conformable time-fractional Biswas–Milovic model. Bifurcation analysis has been done for the governing model via Galilean transformation and phase plane portraits have been used to depict the changes in the behavior of the model by changing the values of the potential parameter. Further, novel and much more generalized Lie symmetries corresponding to the conformable time-fractional Biswas–Milovic model have been obtained and these novel symmetries have been used to obtain new reductions and power series solutions. [ABSTRACT FROM AUTHOR]

The understanding of oxide scale reduction mechanisms after microstructure transformation under different preheating conditions is incomplete. Herein, the reduction kinetics and microstructure transformations of hot rolled steel strip oxide scale during reduction (30% H2–N2) annealing are studied in detail using thermogravimetric and microstructure analyses, and mathematical modeling based on the gas–solid reaction. The results show that the rate‐determining steps of the reduction reaction are nucleation and growth of new phase between 500 and 600 °C, and gas–solid interface reactions between 700 and 800 °C. Microstructure transformation of the oxide scale occurs during the preheating process: at 500 °C, the eutectoid iron preferentially dissolves, and short‐range diffusion of Fe ions into adjacent Fe3O4 increases their content in the metal oxide; at 600 °C, nucleation and growth of Fe1 − yO occur, and some Fe3O4 precipitates and white α‐Fe are found in the Fe1 − yO layer, whereas the majority of the Fe3O4/iron eutectoid structure is retained; between 700 and 800 °C, the oxide scale forms outer and inner layers of Fe3O4 and Fe1 − yO, respectively. After preheating and reduction, the reduced products are porous iron over 500–600 °C, while porous and dense iron occur at 700 °C; dense iron forms as whiskers or granules between 700 and 800 °C. The surface quality of hot rolled steel strip after reduction annealing is subsequently improved as surface cracks are infilled by the newly formed dense iron. [ABSTRACT FROM AUTHOR]

Cryogenic carbon capture (CCC) can preferentially desublimate $\text {CO}_2$ out of the flue gas. A widespread application of CCC requires a comprehensive understanding of $\text {CO}_2$ desublimation properties. This is, however, highly challenging due to the multiphysics behind it. This study proposes a lattice Boltzmann (LB) model to study $\text {CO}_2$ desublimation on a cooled cylinder surface during CCC. In two-dimensional (2-D) simulations, various $\text {CO}_2$ desublimation and capture behaviours are produced in response to different operation conditions, namely, gas velocity (Péclet number $\textit {Pe}$) and cylinder temperature (subcooling degree $\Delta T_{sub}$). As $\textit {Pe}$ increases or $\Delta T_{sub}$ decreases, the desublimation rate gradually becomes insufficient compared with the $\text {CO}_2$ supply via convection/diffusion. Correspondingly, the desublimated solid $\text {CO}_2$ layer (SCL) transforms from a loose (i.e. cluster-like, dendritic or incomplete) structure to a dense one. Four desublimation regimes are thus classified as diffusion-controlled, joint-controlled, convection-controlled and desublimation-controlled regimes. The joint-controlled regime shows quantitatively a desirable $\text {CO}_2$ capture performance: fast desublimation rate, high capture capacity, and full cylinder utilization. Regime distributions are summarized on a $\textit {Pe}$ – $\Delta T_{sub}$ space to determine operation parameters for the joint-controlled regime. Moreover, three-dimensional simulations demonstrate four similar desublimation regimes, verifying the reliability of 2-D results. Under regimes with loose SCLs, however, the desublimation process shows an improved $\text {CO}_2$ capture performance in three dimensions. This is attributed to the enhanced availability of gas–solid interface and flow paths. This work develops a reliable LB model to study $\text {CO}_2$ desublimation, which can facilitate applications of CCC for mitigating climate change. [ABSTRACT FROM AUTHOR]

A facile method for green and selective synthesis of all-crystalline graphdiyne based iso-atomic catalysts (CuEr-GDY) for. CuEr-GDY exhibited transformative properties on artificial photosynthesis of 97.6% selectivity and highest CO yield (181.04 μmol g−1 h−1). Such excellent properties originated from strong interactions between graphdiyne and heterometallic atoms, and between the metal heteroatoms, resulting in incomplete charge transfer to produce high activity. [Display omitted] Herein we report a bimetal atomic catalyst that features atomically dispersed Cu and Er atoms anchored on all crystalline graphdiyne (CuEr-GDY) for efficient artificial photosynthesis converting CO 2 into sustainable fuel at the gas–solid interfaces with water as reducing medium instead of organic reagent. The CuEr-GDY can promote the efficient separation of photogenerated electron-hole pairs to drive water oxidation and CO 2 activation/reduction, together with Cu/Er promoted CO 2 /H 2 O adsorption and CO desorption. This result indicates that bimetallic atoms on the high-crystalline GDY surface have high activity. This heteroatomic catalyst of CuEr-GDY demonstrates high catalytic activity with the reaction selectivity up to 97.6%, and the competitive hydrogen evolution reaction is almost completely suppressed. The CO 2 conversion achieves the CO yield of 181.04 μmol g−1 h−1 under ambient conditions. [ABSTRACT FROM AUTHOR]

Covalent organic framework nanosheets (COF nanosheets) are two-dimensional crystalline porous polymers with in-plane covalent bonds and out-of-plane Van der Waals forces. Owing to the customizable structure, chemical modification, and ultra-high porosity, COF nanosheets show many fascinating properties unique to traditional two-dimensional materials, and have shown potential applications in gas separation, sensors, electronic, and optoelectronic devices. This minireview aims to illustrate recent progress on two-dimensional covalent organic framework nanosheets, from two aspects of on-surface synthesis and potential applications. We first review the synthesis of COF nanosheets at the gas–solid interface. On-surface synthesis under ultrahigh vacuum and on-surface synthesis under vapor are highlighted. In addition, we also review the liquid–solid interface synthesis of COF nanosheets at various substrates, i.e., both crystalline and amorphous substrates. Beyond the synthesis, we highlight state-of-the-art applications of the COF nanosheets, particularly in charge transport, chemical sensors, and gas separation. [ABSTRACT FROM AUTHOR]

The oxidative dehydrogenation of propane (ODP) proceeds catalytically on a gas‐solid interface (heterogeneous reaction) and/or in the gas phase (homogeneous reaction) via a radical chain process. ODP may therefore combine interrelated contributions from the heterogeneous dehydrogenation and gas‐phase reactions, which can be initiated by a catalyst. This study demonstrates that relatively high propene and ethene selectivities (ca. 80 % and 10 %) and propane conversions (viz., 10 % at 500 °C) can be achieved with an empty quartz reactor, which is comparable to the performances of state‐of‐the‐art ODP catalysts (boron‐based or supported VOx). Optimization of the post‐catalytic volume of a h‐BN catalyst bed tested at 490 °C allows to increase the conversion of propane from 9 % to 15 % at a propene selectivity of 77 %, highlighting this parameter as an important variable for improving catalytic ODP performances. [ABSTRACT FROM AUTHOR]

HFO-1234ze(E) is introduced as a new eco-friendly insulating gas for medium-voltage gas-insulated equipment (MV-GIE). However, there are few reports on the partial discharge (PD) induced decomposition and gaseous, solid by-product generation characteristics of HFO-1234ze(E)/CO2. Herein, the PD decomposition characteristics of HFO-1234ze(E)/CO2 were explored based on a needle-plate electrode that simulates the metal protrusion defect in MV-GIE. The partial discharge inception voltage, and phase-resolved partial discharge of HFO-1234ze(E)/CO2 under different mixing ratios, PD intensity and duration time at 0.15 MPa were obtained. Meanwhile, the PD-induced decomposition and generation of gaseous, solid by-products of HFO-1234ze(E)/CO2 were analyzed. A three-zone pattern that describes the gas–solid metal interface interaction was proposed for the first time. It is found that the increase of HFO-1234ze(E) content brings superior insulation performance, while the precipitation of gaseous (CF4, C2F6, CHF3, C3HF7) and solid by-products gradually aggravated. In order to avoid the negative impact of PD-induced decomposition on the insulation and service life of MV-GIE, the optimal HFO-1234ze(E) content of 30% is recommended. Based on the optimal mixing ratio (30% HFO-1234ze(E)/70% CO2), the effect of gas pressure and electrode materials on solid precipitation, breakdown voltage was also explored. This work guides the development of HFO-1234ze(E) based MV-GIE and understanding the solid by-products precipitation mechanism of eco-friendly insulating gas. [ABSTRACT FROM AUTHOR]

The present paper investigates the stabilization of Mg-3Ca alloy and Mg-3Ca/SiC/5p composite foams with and without the addition of 0.12 wt.% beryllium. In Mg-3Ca alloy foam, Be addition has shown a significant improvement in the expansion and pore structure. Whereas, in case of Mg-3Ca/SiC/5p composite foams, the SiC particles stabilized the foam effectively, while Be addition does not show any distinguishable improvement in the foam structure. The formation of BeO and the dense coverage of SiC particles in the gas–solid interface of Mg-3Ca and Mg-3Ca/SiC/5p composite foams, respectively, are the reasons for the foam stabilization. Mg-3Ca/SiC/5p composite foam exhibited lowest foam density of 0.10 g/cm3. The quasi-static compression test shows that Mg-3Ca-0.12Be/SiC/5p composite foam containing Be exhibited lower foam density and higher normalized compressive strength. The energy absorption capacity per unit foam density in Be containing foams was also higher. [ABSTRACT FROM AUTHOR]

Contact electrification exists everywhere and between every phase of matter. However, its mechanism still remains to be studied. The recent triboelectric nanogenerator serves as a probe and provides some new clues about the mechanism present in solid–solid, solid–liquid, and liquid–liquid contact electrification. The gas–solid model still remains to be exploited. Here, we investigated the contact electrification between gases and solids based on the single-electrode triboelectric nanogenerator. Our work shows that the amount of transferred charges between gas and solid particles increases with surface area, movement distance, and initial charges of particle increase. Furthermore, we find that the initial charges on the particle surface can attract more polar molecules and enhance gas collisions. Since ions in gas–solid contact are rare, we speculate that gas–solid contact electrification is mainly based on electron transfer. Further, we propose a theoretical model of gas–solid contact electrification involving the gas collision model and initial charges of the particle. Our study may have great significance to the gas–solid interface chemistry. [ABSTRACT FROM AUTHOR]

The charge accumulation phenomenon at the gas–solid interface under the co-action of DC electric field and temperature gradient is of great significance, but its long-time evolution characteristics are still unclear. In this work, the accumulation and dissipation characteristics of the surface charge on the epoxy-SF6 interface within 216 h were obtained, indicating that, (a) the normal surface electric field is increased by the temperature gradient along the gas–solid interface, which results in a prominent increase in the surface charge density; (b) there are different evolution processes of surface charge in high and low temperature regions under the co-action of DC-temperature gradient, and the increase of the charge trap density caused by the degradation of solid material is considered to be an important reason for the charge evolution; (c) the total charge dissipation ratio within 600 s decreases with the increase of charging time in DC electric field, and the surface charge dissipates mainly to the gas side of the interface; (d) the large amount of charge accumulated at the interface distorts the surface electric field at the triple junction points. The total electric field strength at the low-temperature tri-junction point increases by 35.5%, while the direction of the tangential field at the high-temperature tri-junction point reverses during the long-time co-action of the DC-temperature gradient. The results of this work may be helpful to understand the long-time charge evolution characteristics of the gas–solid interface under the DC-temperature gradient and to reveal the failure mechanism of the gas–solid interface. [ABSTRACT FROM AUTHOR]

Dilute and dense conveying systems through pipelines are a common practice in our everyday life. It is used in many industries to convey a mixture of gas and solids from one location to another through pipes. Gas-solid transport is desirable in some industries but unwanted in others. Depending on the density, size, and shape, these solid particles may result in erosion and subsequent damage to piping and other equipment. Understanding the gas-solid two-phase flow dynamics can help develop efficient and cost-effective pipe transport systems, thereby mitigating the problems associated with the gas-solid two-phase flow. Models for estimating volumetric flow rates and other gas-solid two-phase flow properties are scarce as most are very complex, expensive, and unavailable proprietary commercial software. This study, therefore, developed a simple model using the general energy balance equation and relevant mixing theories for estimating the volumetric flow rate of natural gas-solid two-phase flow in horizontal pipes. The results from the model showed that the gas-solid flow rate is a function of pipe diameter, pressure drop, pipe length, solid volumetric concentration, solid-to-gas density ratio, and solid-to-gas friction factor ratio. [ABSTRACT FROM AUTHOR]

The solid-to-gas phase transition of potassium during biomass combustion significantly impacts ash-related issues in bioenergy systems, affecting operational efficiency and equipment longevity. However, the specific mechanisms and kinetics of this transition process remain inadequately understood. This work investigates the time-resolved transition of solid-phase potassium to the gas phase during the combustion of rice husk and wheat straw pellets, combining experimental measurements with theoretical modeling. Tunable diode laser absorption spectroscopy (TDLAS) was employed to measure atomic potassium concentrations 15 mm above burning pellets tray, where gas-phase equilibrium is approached. Key combustion characteristics including thermogravimetric profiles, spectral radiation, and temperature were simultaneously monitored. A novel multi-step model was developed to describe the transition of different forms of solid-phase potassium (organic, exchangeable, and inorganic) to the gas phase. This model integrates TDLAS measurements, observed combustion characteristics, and biomass physicochemical properties. Thermodynamic equilibrium calculations were used to estimate the atomic potassium fraction from total gaseous potassium. The results showed that the solid-to-gas phase transition of organic potassium synchronizes with volatiles release. In contrast, the maximum emission rates of inorganic and exchangeable potassium occurred at the onset of char combustion. The developed model agrees well with the online detection experiments and were further validated by offline ICP analysis of residual ash. While not directly simulating gas-solid interface reactions near the particle surface, this work lays groundwork for future multi-scale modeling of particle-laden flows and reactor-scale phenomena in biomass combustion systems. [ABSTRACT FROM AUTHOR]

Tritium safety plays a crucial role in D -T fusion engineering. During normal operations, tritium(T) is typically dissolved with protium(H) or deuterium(D) in structural materials. However, there are still controversial issues related to the synergistic isotopic effects when considering T permeation through metals with H/D. In this work, a numerical model is built to describe the co-permeation behavior of multi-component hydrogen isotopes through metals in all rate-limited regimes. This model involves isotope exchange reactions in the gas phase, molecular dissolution, and atomic recombination at the gas-solid interface, as well as the diffusion process in the bulk. By simulating the mixed hydrogen gas permeation through various metals, different results are observed. In surface limited regime, the effective permeation flux of D is slightly enhanced by the presence of H due to isotopic effect. In diffusion-limited regime, the recombination of heteronuclear hydrogen molecules (HD) will deviate the equilibrium concentration of D on the upstream side from Sievert's Law, thereafter suppressing the D permeation flux on the downstream side. [ABSTRACT FROM AUTHOR]

A design optimization method applicable to both rarefied and continuum gas flows with good efficiency is proposed in the framework of gas-kinetic theory. The method follows the methodology of topology optimization where the areas of gas and solid are marked by the material density, based on which a fictitious porosity model is used to reflect the effect of the solid on the gas and mimic the diffuse boundary condition on the gas-solid interface. The formula of this fictitious porosity model is modified to make the model work well from the free-molecular flow regime to the continuum flow regime. To find the optimized material density, a gradient-based optimizer is adopted and the design sensitivity is obtained by the continuous adjoint method. To solve the primal kinetic equation and the corresponding adjoint equation, efficient multiscale numerical schemes are constructed. Several airfoil optimization problems are solved to demonstrate the performance of the present design optimization method in wide ranges of flow speed and gas rarefaction. It is found that the thickness of the optimized airfoil first increases and then decreases as the Knudsen number increases, and on the supersonic condition the optimized airfoil has quite different shapes of leading edge for different degrees of gas rarefaction. [ABSTRACT FROM AUTHOR]

• Carbon oxygen framework (COF) fabricated using hexahydroxyphyenylene and graphene oxide. • Incorporating graphene oxide (GO) and COF increase C C bonds, boosting catalytic activity. • Liquid free electrolyte half-cell design applied for gaseous dichloroethane reduction. • Effective reduction of gaseous dichloroethane in electrochemical reaction with GO-COF. To address the challenges associated with the degradation of gaseous dichloroethane (DCA), this study presents an innovative electrocatalytic reductive methodology using graphene oxide (GO) and hexahydroxyphenylene (HHTP) as the carbon oxygen framework (COF). The approach stands out due to its liquid-free electrolyte half-cell design, featuring a gel layer interposed between the COF and the membrane without additional humidity. The structure and electrochemical properties of the COF were characterized using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray diffraction (SEM-EDS), Fourier-transform infrared (FTIR) spectroscopy, and cyclic voltammetric (CV) analyses after being coating on the desired substrate under fabrication conditions including drying temperature, time, and coating cycles). In a 1-hr batch mode test, the COF coated on a carbon substrate exhibits 75 % degradation efficiency at an initial DCA of 0.46 mmol, with a corresponding reduction rate of 0.015 mg min−1. Gas chromatography-mass spectrometry (GC–MS) conclusively identified chloroethene and ethene as the resultant reaction products. This approach offers the role of advanced catalysis materials in addressing electrochemical degradation of DCA as a potential for environmental remediation and sustainable chemical processing. [ABSTRACT FROM AUTHOR]

The adsorption and phase behavior of two model fluids, both with square well inter-particle attraction and site-site associative interaction, in slit-like pores have been studied in the framework of a density functional theory. The mean field approach and the first-order mean spherical approximation have been applied to account for the attractive interactions. The chemical association effects are taken into account by using the first-order thermodynamic perturbation theory of Wertheim. A set of parameters for each fluid model has been chosen according to the work of [Clark et al., Mol. Phys. 104, 3561 (2006)], to describe successfully the vapor-liquid coexistence of water in the bulk phase. The influence of the slit-like pore width and of the strength of gas-solid interaction energy on the vapor-liquid coexistence envelope under confinement has been explored in detail. The theory and the results of the present work are valuable for further exploration of a wide set of models of associating fluids and of fluids with complex molecular architecture in different adsorbents, and to deal with activated carbon surfaces. [ABSTRACT FROM AUTHOR]