Mutual Reaction Research Articles

Understanding the effect of holding time on interfacial microstructure evolution and mechanical properties of Ti3AlC2/Zr-4 brazed joints

In this work, the brazing of Zircaloy-4 (Zr-4) to Ti3AlC2 ceramic was investigated using a Ti–13Zr–21Cu–9Ni (wt.%) amorphous alloy at 930 °C with a holding time of 5–60 min. The typical multilayer structure of the joint was carefully characterized as Ti3AlC2/ZrC/Zr [Ti]ss + [Zr(Ti)]2 [Cu(Ni)]/Zr [Ti]ss/Zr-4. Ti3AlC2 was decomposed into TiCx due to the de-intercalation of Al, and Zr-4 dissolved into the molten amorphous TiZrCuNi fillers to form a Zr-based alloy which reacted with TiCx to form a ZrC particle layer on the Ti3AlC2 side. The microstructures and mechanical properties of the brazed joint were significantly influenced by dwell time, and the underlying evolution mechanisms were addressed based on the considerations of mutual dissolution, diffusion, and reaction among Ti3AlC2, Zr-4, and molten amorphous alloys. With the extension of holding time, the amount of [Zr(Ti)]2 [Cu(Ni)] in the brazed joints decreased gradually, while the ZrC layer thickened with (Ti, Zr)ss formed around the ZrC particles. The maximum shear strength of the joint, with an average strength of 187 ± 34 MPa, was achieved by brazing at 930 °C for 5 min. A detailed fracture analysis was conducted to determine the failure mechanism. This work provides a reference for brazing other MAX phase materials and alloys.

Solution infiltrated lanthanum nickelate–GDC composite cathode via flash-light sintering for intermediate temperature solid oxide fuel cells

Solid oxide fuel cells (SOFCs) require high operating temperatures to minimize the oxygen reduction reaction resistance at cathode and increase the ionic conductivity of oxygen. However, at high operating temperatures, their stability during long-term operation degrades because of material deterioration and the mutual chemical reactions occurring at the interfaces. Herein, an electrode–electrolyte composite is fabricated by solution infiltration of lanthanum nickelate (LNO) electrode material into a GDC electrolyte layer to ensure more reaction sites compared with the conventional powder mixing of the electrode and electrolyte material. Further, the conventional thermal sintering process is replaced with the flash-light sintering process. Thus, the performance of the LNO–GDC cathode cell manufactured by flash-light sintering improves owing to suppression of grain growth of the infiltrated LNO particles. The microstructures of the infiltrated solution and composite layer of the electrolyte material are analyzed using field-emission scanning electron microscopy, and the crystallinity of the LNO nanoparticles is analyzed using high-resolution transmission electron microscopy. A maximum power density of 1.1 W/cm2 is achieved, an improvement of 58 % over the LSCF cell without infiltration at 750 ℃. This study is expected to contribute to the commercialization of SOFCs by replacing conventional thermal sintering.

Insights into the co-pyrolysis interaction of cellulose and Zhundong coal via ReaxFF molecular dynamics simulation

Experiments on the co-pyrolysis of coal and cellulose were conducted using a fixed-bed reactor in this paper. The results demonstrated that co-pyrolysis increases gas and char yields while reducing tar yield. The reactive force field molecular dynamics (ReaxFF MD) was then used to simulate co-pyrolysis in order to analyze the mutual reaction between coal and cellulose from the perspective of carbon skeleton, enabling the co-pyrolysis mechanism to be examined precisely. The results demonstrated that co-pyrolysis accelerates the crosslinking of cellulose fragments and coal char. The cellulose-derived component in cross-linked char (char products containing both cellulose and coal fragments) rises from 0.21 wt% at 2000 K to 12.82 wt% at 3000 K, resulting in higher char production. The examination of the yields and distribution of co-pyrolysis products at 2400 K reveals that the volatiles generated by cellulose and coal char undergo mainly crosslinking reaction, resulting in a lower tar yield and a higher inorganic gas yield. Due to the combination of oxygen-containing functional groups in the coal char with cellulose volatiles and free hydroxyl groups, the oxygen-containing active functional groups were consumed, rendering the cross-linked char more stable and inactive, thereby suppressing coal polymerization.

Ultrafine particles formation from ozonolysis of gas- and particle-phases of cigarette smoke

Cigarette smoke and ozone (O3) are two main pollutants in indoor environments and their mutual reaction can generate substantial detrimental substances having synergistic influences on the environment and human health. The aging process of cigarette smoke in the atmosphere is mainly gone through ozonolysis reaction attracting increasing attention in recent years. Herein, the ozonolysis reaction of cigarette smoke with indoor O3 concentrations has been investigated in a Teflon chamber. The gas- and particle-phases of cigarette smoke are divided and their individual ozonolysis process can generate ultrafine particles (UFPs) with high number concentrations. The chemical compositions of the gas- and particle-phases of cigarette smoke as well as their nascent UFPs are measured and their differences during the ozonolysis have been clearly observed with vacuum ultraviolet (VUV) photoionization mass spectrometry. In particular, several representative key species of cigarette smoke, i.e., the gas-phase furan and 2,5-dimethylfuran and the particle-phase nicotine, as well as their ozonolysis products are definitely identified and play an important role in the nucleation formation of UFPs. Their ozonolysis reaction mechanisms are also discussed. In addition, this work demonstrates that the ozonolysis of the particle-phase of cigarette smoke contributes more UFPs than that of the gas-phase.

Lyrical And Musical Genres in Goran's Poems

This research is entitled: (Lyric and melody, Genres in Goran's Poems) which is a new look at two aspects, namely (genre, external and internal music of Goran's poems). It attempts to present the genre in all its details and characteristics, on the other hand, to determine it according to the characteristics of the lyrical genres of Goran's poems. Because lyrical genres are related to many aspects such as hymns, songs, poems, etc. Therefore, an attempt has been made to explain the aspects that are directly related to lyricism and create mutual influences and reactions. Therefore, "Outer and Inner Music in Goran's Poems" will be part of this research. The research was conducted according to the method (descriptive_analytical), which explains the lyricism of Goran in terms of genres and at the same time interprets the outer and inner melody of the poet's poems. This paper consists of an introduction, two parts, conclusions and a list of sources.

Analysis of the chemical diffusion master equation for creation and mutual annihilation reactions

We propose an infinite dimensional generating function method for finding the analytical solution of the so-called chemical diffusion master equation (CDME) for creation and mutual annihilation chemical reactions. CDMEs model by means of an infinite system of coupled Fokker–Planck equations the probabilistic evolution of chemical reaction kinetics associated with spatial diffusion of individual particles; here, we focus an creation and mutual annihilation chemical reactions combined with Brownian diffusion of the single particles. Using our method we are able to link certain finite dimensional projections of the solution of the CDME to the solution of a single linear fourth order partial differential equation containing as many variables as the dimension of the aforementioned projection space. Our technique extends the one presented in Lanconelli [J. Math. Anal. Appl. 526, 127352 (2023)] and Lanconelli et al. [arXiv:2302.10700 [math.PR] (2023)] which allowed for an explicit representation for the solution of birth-death type CDMEs.

Thermal conductive nylon 6 composites using hybrid fillers to construct a three‐dimensional thermal conductive network

AbstractThe rapid progress in miniaturization and integration of semiconductor power devices has made heat dissipation a critical concern in the development of high‐performance semiconductor devices, thereby increasing the demands for the heat transfer efficiency of polymer composites. To address this issue, an efficient three‐dimensional (3D) heat conduction network structure is constructed in the polymer matrix by leveraging the mutual reaction of amino and epoxy groups on the surface of the filler treated by coupling during the melt mixing process, this approach leads to an enhancement in the thermal conductivity of the composites. First, the inert surfaces of graphene nanosheets (EX‐G) and carbon fibers (CF) are coated with polydopamine (PDA) to form active sites. Subsequently, the graphene (EX‐G), alumina (Al2O3), and carbon fiber (CF) are treated with an amine coupling agent (KH550) and epoxy coupling agent (KH560), respectively. Notably, at a filler content of 25 wt%, the thermal conductivity (TC) of the composites increases by approximately 282% compared to pure nylon 6. This research contributes novel insights into the field of thermally conductive polymer composites.Highlights The surface of the EX‐G and CF covered by PDA generates active sites. Fillers reduce the interface thermal resistance through chemical bonds. Fillers surface reaction builds a 3D thermal conductive network. 3D network structure can significantly improve the TC of composites. Only 25 wt% of hybrid fillers in a 282% increased TC of composites.

Probing into the optimum preparation and the chemical durability of Sr0.5Zr2(PO4)3-SmPO4 dual-phase ceramics for nuclear waste forms via in-situ synthesis

In this work, Sr0·5Zr2(PO4)3-SmPO4 dual-phase ceramics were prepared via in-situ synthesis process, which is a potential novel nuclear waste form for immobilizing the fission product 90Sr and the trivalent actinide radionuclides in high-level waste (HLW). And the preparation technology, microstructure and chemical durability of Sr0·5Zr2(PO4)3-SmPO4 dual-phase ceramics were systematically investigated. It was confirmed that the optimum microwave-sintering temperature (1050 °C) and heat preservation time (1.5 h) is estimated by Archimedes method. Besides, the as-prepared samples that were consisted of strontium zirconium phosphate (SrZP) and monazite showed the remarkable densification, in which the two crystalline phases were intermixed well with each other. Meanwhile, the formation and evolution of microstructure was also consistent with the variational rule of Sr0·5Zr2(PO4)3/SmPO4, indicating that there was not mutual reaction during the in-situ synthesis process. The PCT and MCC-1 experimental results demonstrated that the elemental normalized leaching rates of tested samples are all at a low level (LRSr∼10−4 g‧m−2‧d−1, LRZr∼10−8-10−6 g‧m−2‧d−1, LRSm∼10−7-10−5 g‧m−2‧d−1 and LRP∼10−4 g‧m−2‧d−1). It is indicated that Sr0·5Zr2(PO4)3-SmPO4 dual-phase ceramics possesses excellent chemical durability for HLW disposal.

Voice and Exit: Mutual Funds' Reactions to ESG Scandals

Voice and Exit: Mutual Funds' Reactions to ESG Scandals

Mutual neutralization in collisions of Li+ with CN.

The mutual neutralization reaction in collisions of Li+ with CN- is a promising candidate for rigorous multi-dimensional ab initio studies of atom-molecule charge transfer processes. The reaction is driven by the non-adiabatic interaction between the lowest two 1A' electronic states at large Li-CN distances, resulting in a large cross section for mutual neutralization. As a first step, the relevant adiabatic potential energy surfaces and non-adiabatic interaction are computed ab initio, and the process is studied quantum mechanically using the vibrational sudden approximation, where the vibrational and rotational motions of the CN molecule are assumed to be frozen during the collision.

A novel strategy to construct hydrogels with anti-swelling and water-retention abilities by covalent surface modification.

Hydrogels have been widely used in various fields due to their diverse properties and flexible preparation methods. However, limited by the open network structure, hydrogels inevitably lose water in air or absorb water in aqueous solution, resulting in the loss of intrinsic functions, which severely hinders their practical applications. To address this issue, a general strategy was developed by subsequently modifying the surface of hydrogels with branched polyethyleneimine (PEI) and (3-(methacryloxy)propyl)trimethoxysilane (MPS) to covalently construct a dense cross-linked siloxane layer on the hydrogel surface. As a proof of concept, poly(2-(dimethylamino)ethyl methacrylate)/sodium alginate (PDMAEMA/SA) hydrogels were chosen as the model hydrogels to verify the feasibility of this strategy. The hydrogels adsorbed PEI to form amino-rich surfaces through hydrogen bonding, followed by covalently grafting MPS through rapid and catalyst-free mutual chemical reactions between acrylates and amine groups, as well as the hydrolysis of MPS. After modification, robust hydrophobic surfaces were successfully fabricated on the hydrophilic hydrogels. The modified hydrogels exhibited extraordinary anti-swelling and water-retention abilities. As the most typical intrinsic properties of hydrogels, the conductivity and sensing performance were well preserved. The strategy reported here provides a new insight into the construction of hydrogels with anti-swelling and water-retention abilities.

The influence of the variability of the support of the mortar base plate on the quality of the results obtained in the process of its numerical design

Due to the high costs associated with the purchase of ammunition and firing in certified training ground centers, tests of retaining plate deformations are increasingly replaced by computer simulations using numerical models. Computer programs usually use a single-parameter subsoil model (Winkler-Zimmermann) for calculations, which requires providing the subgrade susceptibility coefficient. The subgrade compliance coefficient is intended to determine the mutual reaction of the subgrade and the structure due to the pressure exerted on the soil by the retaining slab, which settles. When designing slabs in computer programs, it is assumed that the substrate compliance coefficient is constant. Determining the impact of the soil on the retaining slab is important when analyzing its deformations. The subject of the work was the analysis of the influence of ground support on the results obtained during modeling of the retaining slab. In order to obtain data for FEM analysis and validation, the actual strains occurring on the thrust plate were measured using strain gauge rosettes. The plate deformations were measured during field shooting tests. In order to vary the influence of supporting the slab on the ground and obtain reliable stress values on the slab surface, a method of successive iterations was proposed. Calculations are performed using this method until the error is smaller than the assumed one.

Mixed colors by combustion of mixed homogeneous pyrotechnics and heterogeneous charges

AbstractThe combustion of mixed homogeneous pyrotechnic compositions and heterogeneous charges is studied experimentally with the aim of producing a selectable wavelength signal flare. The heterogeneous charge was perceived as a mixed color by a distant observer. A model for color chromaticity coordinates of homogeneous mixtures was derived that includes the mass, mass‐based burn rate and luminous intensity ratios of the constituting color compositions. This model can predict the expected dominant wavelength of a mixed composition. It can also handle the spacing of chromaticity coordinates of mixed compositions on a straight line in the CIE diagram between chromaticity coordinates of constituting colors. With two series of color composition mixtures, it was demonstrated that the chromaticity coordinates of the mixtures could be at, or slightly deviate, from the straight line connecting the chromaticity coordinates of the constituting compositions. It indicates there is little to no influence of flame temperature and mutual pyrotechnic reactions.

THE INFLUENCE OF THE CATALYST ON THE RATE CONSTANT OF THE CHEMICAL REACTION OF ESTERIFICATION OF OLEIC ACID WITH METHANOL

Catalysis and catalysts play an important role in modern technology. Catalysis means a change in the rate of a chemical reaction under the influence of a substance that does not change chemically as a result of the reaction. This substance is called a catalyst. The catalyzed reaction proceeds on a different reaction path than the uncatalyzed reaction, thanks to the participation of the catalyst. The reactants are absorbed on the surface of the catalyst, and then a mutual reaction of the adsorbed species occurs. The reaction produc- es a product that is desorbed from the surface, while the catalyst remains unchanged and ready for a new reaction cycle. An important piece of information for evaluating the quality of a catalyst is the rate of the reaction in which it participates. The subject of kinetic research is the study of the influence of process pa- rameters on the reaction rate. It is safe to say that the study of reaction kinetics is a central part of chemical reaction engineering. Therefore, the study of the kinetics of real heterogeneous catalysts is of particular im- portance, both for the improvement of existing catalysts and for the development of new ones. These tests involve determining the influence of process parameters such as the type of catalyst present, temperature, pressure, and concentration of reactants and products on the reaction rate. In this work, the influence of the mass of the catalyst at a certain temperature on the rate constant of the chemical reaction of esterification of oleic acid with methanol was studied. The catalyst used was mesoporous silica, an amorphous solid that can be obtained by drying hydrogels. It was found that as the mass of the catalyst increases, the rate of the chemical reaction constant also increases, i.e. the rate of the esterification reaction increases.

Probing on Mutual Interaction Mechanisms of the Ingredients of Al/CuO/PVDF Nanocomposites.

In this paper, several binary and ternary metastable intermixed nanocomposites Al/CuO, Al/PVDF, CuO/PVDF, and Al/CuO/PVDF have been prepared by simple mechanical mixing and ball milling followed by spray drying methods. In this way, the interfacial structure could be well tuned and compared in terms of reactivity. The nonisothermal DSC curves results showed that the exothermic reaction of Al/CuO/PVDF could be divided into three steps. In addition, it has been shown that for the same formulation, the reaction efficiency, pressurization capacity, and thermal reactivity are greatly dependent on the interfacial structure. As a typical example, composite Al@PVDF/CuO, where Al is fully covered with PVDF, exhibited a higher energy release of 10.7 kJ·cm-3 and pressurization rates of 22.79 MPa·s-1·g-1. The reaction between Al and PVDF has been facilitated in both extent of reaction and efficiency due to their intimate contact. Based on the thermal analysis, condensed combustion product analysis, and gaseous phase identification, the mutual reaction mechanisms of Al/CuO/PVDF have been proposed. The most likely reactions that occurred at each stage of the reaction are summarized, providing insight into the complicated underlying mechanisms. It shows that the regulation of energy release rates and improved efficiency could be easily realized by predesigned interfacial structures.

Theoretical study on hydrogen abstraction reactions from pentane isomers by NO2

The rate constants for the H-abstraction reactions of C5H12 + NO2 are calculated by high-accuracy electronic structure calculations and transition state theory (TST). The investigation includes three pentane isomers, neopentane, n-pentane, and iso-pentane, each of which leads to the formation of three different HONO isomers, namely cis-HONO, trans-HONO, and HNO2. The lowest energy conformers of all relevant species are determined through geometry optimization, frequency analysis, and one-dimensional hindered rotor scanning at the M06-2X/6-311++G(d,p) level of theory, and are further re-optimized using the B2PLYP-D3/cc-pVTZ method. The single point energies of all the reactants, products, and transition states are obtained at the DLPNO-CCSD(T)/CBS level of theory. Traditional transition state theory was employed to derive the rate constants, which were then fitted to obtain the kinetic parameters in the Arrhenius expression. Simulation results show improved performance in ignition delay times and oxidation species prediction, when the calculated reaction rate constants are implemented in the literature n-pentane kinetic models. The results offer enhanced comprehension of the chemistry of C5H12 + NO2, and will aid in the understanding of the mutual reactions of large hydrocarbon fuels and NOx.

Analysis of sintering process of Alumix431-B4C composites

This paper presents the results of a study on the sintering process of composites made of a mixture of Alumix 431 powders with B4C boron carbide. Sintering was carried out at the following temperatures: 550, 580 and 600 ℃. The process of sintering Alumix powders is a very complex issue due to the possibility of many types of mutual reactions of the elements constituting its components and their interaction with boron carbide. The study included the preparation of green compacts from a mixture of powders with the addition of 5 wt % B4C and sintering in a NETZSCH 402ES/3 differential dilatometer; the density and microstructure of the sinters were examined using scanning microscopy and X-ray phase analysis. Analysis of the dilatometric curves allowed the sequence of the emerging liquid phases and their impact on the course of dimensional changes as well as the microstructure of the finished composites to be determined, indicating the importance of the reaction of the aluminium matrix with magnesium, copper and zinc. It was also indicated that the B4C boron carbide addition may decompose, resulting in the appearance of B12Mg and Al4C3 phases. The research also showed that the addition of carbide did not adversely affect the density of the sinters as composites with a density exceeding 95 % of the theoretical density were obtained.

The Ultrasensitive Detection of Aflatoxin M1 Using Gold Nanoparticles Modified Electrode with Fe3+ as a Probe.

The increasing incidence of diseases caused by highly carcinogenic aflatoxin M1 (AFM1) in food demands a simple, fast, and cost-effective detection technique capable of sensitively monitoring AFM1. Recent works predominantly focus on the electrochemical aptamer-based biosensor, which still faces challenges and high costs in experimentally identifying an efficient candidate aptamer. However, the direct electrochemical detection of AFM1 has been scarcely reported thus far. In this study, we observed a significant influence on the electrochemical signals of ferric ions at a gold nanoparticle-modified glassy carbon electrode (AuNPs/GCE) by adding varying amounts of AFM1. Utilizing ferricyanide as a sensitive indicator of AFM1, we have introduced a novel approach for detecting AFM1, achieving an unprecedentedly low detection limit of 1.6 × 10-21 g/L. Through monitoring the fluorescence quenching of AFM1 with Fe3+ addition, the interaction between them has been identified at a ratio of 1:936. Transient fluorescence analysis reveals that the fluorescence quenching process is predominantly static. It is interesting that the application of iron chelator diethylenetriaminepentaacetic acid (DTPA) cannot prevent the interaction between AFM1 and Fe3+. With a particle size distribution analysis, it is suggested that a combination of AFM1 and Fe3+ occurs and forms a polymer-like aggregate. Nonetheless, the mutual reaction mechanism between AFM1 and Fe3+ remains unexplained and urgently necessitates unveiling. Finally, the developed sensor is successfully applied for the AFM1 test in real samples, fully meeting the detection requirements for milk.

Synthesis of silicon carbide nanoparticles from amorphous carbon: Based on the domain structure of electrically calcined anthracite

Based on the domain theory, the domain structure of electrically calcined anthracite was studied for the first time. The carbon microstructure of the electrically calcined anthracite was analyzed using atomic force microscopy (AFM). The analysis revealed that the carbon microstructure comprised microdomains with particle sizes below 30 nm and domains with particle sizes below 200 nm. In addition, non-graphitizable carbon structures formed by partial microdomain and domain structures were difficult to grow. Thus, we successfully synthesized novel β-type silicon carbide (β-SiC) nanoparticles with larger particle sizes below 200 nm and smaller particle sizes below 60 nm using a non-graphitizable carbon composed of carbon nanoparticles as the main raw material. Through calculation and analysis, the synthesis mechanism revealed that due to the presence of highly reactive interfacial regions between the domains of electrically calcined anthracite, silicon first diffused to the highly reactive interface between the domains of electrically calcined anthracite and reacted with the highly active carbon atoms in it to form silicon carbide, resulting in a certain degree of volume expansion. The volume expansion led to the cracking and dispersion of the domains, which further led to mutual diffusion and reaction within the exfoliated domains to generate SiC nanoparticles. And the non-exfoliated SiC nanoparticles generated at the reaction interface on the surface of electrically calcined anthracite were observed by the AFM.

Numerical investigation on a floating self-reacting resonant wave energy converter

A self-reacting resonant C-shaped wave energy converter (SR-C-WEC) consisting of a pair of resonant sub-C-WECs connected by a rigid frame is proposed, which uses the two sub-C-WECs to provide mutual reaction force to solve the efficiency problem caused by floating WECs being hard to provide enough reaction force on WEC and uses the controllable resonant WEC to solve the efficiency problem caused by the temporal variability of waves. Resonant control and equivalent wave force control models are proposed to maximize the absorbed power. The effect of spacing between two sub-C-WECs, natural period, PTO damping and mooring stiffness to absorbed power is investigated. It is found that SR-C-WEC can achieve resonance at each wave condition and the power generation is maximum when the spacing is equal to half wavelength, which is comparable to the power generation when the frame is fixed. In a real sea condition, when the spacing is adjusted or not, the difference in average annual power is only 8.3%. Therefore, constant spacing can be used to simplify the structure and facilitate the application of SR-C-WEC. It is predicted that SR-C-WEC can reach 3638 effective power generation hours per year in real seas off China.