Inclusion Reaction Research Articles

Simulation of Ladle Refining Reactions in Si–Mn‐Killed Steel

Steel quality, to a large extent, is controlled by ladle refining reactions. The understanding of such reactions can help to prevent the formation of unwanted phases and improve the overall high‐temperature process control. A new approach, namely, the multioxide inclusion kinetic model has been recently developed to simulate steel–inclusion reactions in liquid steel. The coupling of this kinetic model with a multicomponent, multiphase steel–slag reaction interface model leads to an overall model framework to predict the evolution of steel, slag, and inclusion composition. The current work shows the application of the model to simultaneous deoxidation and desulphurization during ladle refining of Si–Mn‐killed steel. The model shows good performance with industrial data. It is demonstrated that for ladle refining practices, silica‐rich slags should be strictly used with basicity (CaO/SiO2) between 1 and 1.2 and with Al2O3 content less than 5 wt%. Additional simulations are also carried out to reveal the capability of the model to aid in online process control. Finally, certain limitations of the current model are discussed.

Highly robust quantum mechanics and umbrella sampling studies on inclusion complexes of curcumin and β-cyclodextrin

The poor aqueous solubility of curcumin (CUR) obstructs its wide utilization in nutraceuticals, cosmetics, and pharmaceutical companies. This study is dedicated to investigate the stability of CUR inside the hydrophobic pocket of β-cyclodextrin (β-CD), hydroxypropyl-β-CD (HP-β-CD), and 2,6-Di-O-methyl-β-CD (DM-β-CD). Initially, molecular mechanics (MM) calculations and subsequently quantum mechanical (QM) calculations were performed on inclusion complexes to strengthen the MM results. We performed microsecond timescale MD simulations to observe the structural dynamics of CUR inside the cavity of CDs. We elucidated the most stable binding orientations of CUR inside the cavity of CDs based on binding free energy obtained from the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) and umbrella sampling simulations. Furthermore, the two-layered ONIOM (B3LYP/6-311+G(2d,p):PM7) method with CPCM implicit water model was used to derive the complete energetics and thermodynamics of inclusion complexes at 1:1 stoichiometry. Each inclusion reaction was exothermic and spontaneous. The chemical reactivity and kinetic stability of inclusion complexes were described by HOMO-LUMO molecular orbital energies. In conclusion, our studies revealed that HP-β-CD had the highest binding affinity for CUR with the most negative complexation energy (−6520.69 kJ/mol) and Gibb's free energy change (−6448.20 kJ/mol). The atomic-level investigation of noncovalent interactions between CUR and the hydroxypropyl groups in HP-β-CD/CUR complex may be helpful to drive new derivatives of HP-β-CD with better host capacity. The computational strategy adopted here might serve as a benchmark for increasing the solubility of numerous clinically significant molecules.

Revealing the kinetics of non-metallic inclusion reactions in steel using in-situ high temperature environmental scanning electron microscopy

The kinetics of solid-state reactions involving non-metallic inclusions (NMIs) in steel is a topic of growing interest due to the need to understand the effects of heat treatments on NMI composition and stability. In this study, a High Temperature Environmental Scanning Electron Microscope (HT-ESEM) is utilized to conduct in-situ observations of various types of NMIs, including calcium aluminate complex, CaS, MgAl2O4-CaS, MnS, and TiN, in steels at temperatures of 800 °C and 900 °C for different holding times. The observed morphological variations in the NMIs indicate a decrease in the fractions of CaS and MnS, promoting void formation and ferrite–austenite phase transformation. To estimate the NMI reactions with the residual atmosphere in the sample chamber during experiments, HT-ESEM-driven thermodynamic calculations have been performed using FactSage 8.2 software. These calculations provide valuable insights into the interpretation of the experimental data, facilitating a better understanding of the complex NMI reactions in steel.

Comparative study of the inclusion complexation of uracil and 5-fluorouracil with native and modified cyclodextrins: some theoretical and practical

In this study, the inclusion complexes of α-, β-cyclodextrins and derivatives hydroxypropyl-α-, hydroxypropyl-β-cyclodextrins with uracil and the anti-cancer agent 5- fluorouracil were demonstrated by UV-Vis spectroscopy and quantum chemical calculations. The complexes stability constants and the thermodynamic parameters for the 1:1 stoichiometry inclusion complexes were obtained and compared. The thermodynamic analysis of the studied complexes showed that the inclusion reaction is an exothermic spontaneous reaction and is an enthalpy driven process for the temperature domain of 298K to 313K. Theoretical calculations were performed on complexes to examine the energetic quantities involved in the stability of the complexes. The correlation of the energy parameters obtained from experimental and theoretical data suggests a high affinity between cyclodextrins and both uracil and 5-fluorouracil molecules.

Comments on oxide inclusion formation/removal in the ESR process

ABSTRACT There are numerous studies of inclusions in ESR material but several questions remain as to the way in which they are removed and formed during the process. We present a critical survey of the existing data with the intention of assembling what is currently known of the mechanisms and from that survey presenting the potential routes for the inclusion behaviour. We conclude that there is a significant difference in inclusion comportment between that in small furnace processing and that in large industrial operations. The difference arises in the temperature regime, metal residence time in the reaction zones and in the operating differences in the electrode melting geometry. As a result, it is also concluded that care must be taken in relating experimental data from laboratory ESR furnaces directly to describing inclusion reactions in the industrial process. Additionally, mechanical property results obtained from small ingots, which are influenced by inclusion content, should not be taken as the same properties of ingots made on the industrial scale.

Modeling Study of Steel–Slag–Inclusion Reactions During the Refining of Si–Mn Killed Steel

Complex deoxidation by Si and Mn is beneficial for certain steel long products since it leads to the formation of low‐temperature melting manganese silicates. However, the introduction of Al via steel–slag reactions can lead to unwanted inclusion formation, which can cause nozzle clogging down the process line. To simulate steel–slag–inclusion reactions during the refining of steel, a kinetic model based on the mass transfer of steel species has been developed for inclusions and integrated with a previously developed steel/slag coupled reaction model. Using the model, the rate‐determining step for inclusion transformation is clarified, and the effect of slag–metal reactions on inclusions is investigated. The model calculations are validated using experimental data reported in the literature. Subsequently, the influence of slag compositions on the chemistry of inclusions and the effect of mass transfer coefficient on deoxidation characteristics is examined through a parametric study. The results are helpful for understanding inclusion dynamics during ladle refining of Si–Mn killed steel.

Effect of preparation methods on tosufloxacin tosylate/ hydroxypropyl-β-cyclodextrin inclusion complex

The main purpose of this work was to compare the effects of the four preparation methods on the TFLX/HP-β-CD inclusion complex. The effects of different preparation methods on the inclusion complex were investigated by SEM, DSC, PXRD, FT-IR and 1H NMR. All the characterization information indicated that the four preparation methods could cause interaction between TFLX and HP-β-CD, but the inclusion complex prepared by solvent evaporation has more reaction sites. Phase solubility experiments demonstrated that the inclusion reaction was spontaneous. In vitro dissolution experiments showed that the dissolution of the inclusion complex in water was: solvent evaporation method (64.39%) > grinding method (42.37%) > ultrasonic method (40.00%) > freezing method (36.08%), and all higher than pure TFLX and physical mixture. These results suggest that the solvent evaporation is the most suitable method for preparing TFLX/HP-β-CD inclusion complexes.

Preparation of fragrant collagen fibers by cross-linking with β-cyclodextrin and inclusion of l-menthol: characterization, release behavior and reusability evaluation

To solve the poor fragrance retention of collagen-based materials, β-cyclodextrin derivatives bearing multiple aldehyde groups (MACD) were used to cross-link with collagen fibers (COLF) and subsequently to include l-menthol. The structure and performance of MACD, MACD cross-linked COLF (CD-COLF) and CD-COLF included with l-menthol (MEN/CD-COLF) were characterized by Fourier transform infrared (FTIR), ultraviolet-visible spectroscopy (UV-vis), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results showed that the l-menthol loading content in CD-COLF was 2.05 mg/g, 2.85 times higher than that of the uncross-linked COLF. The stability constant (Ka) of MEN/CD-COLF at 25 °C was 364.78 L/mol, ΔH was −19.29 KJ/mol, ΔS was −15.62 J/(mol·K), and ΔG was −14.63 KJ/mol, which indicated the inclusion reaction was spontaneous, and the as-formed MEN/CD-COLF was stable. Meanwhile, the MEN/CD-COLF was more difficult to release l-menthol. The release rate was affected by temperature, the release equilibrium was prolonged, and the cumulative release degree was relatively lower. Furthermore, the fragrant collagen fibers were reused by washing with ethanol and dried under vacuum, and the regeneration was repeated 10 times. Therefore, the fragrant collagen fibers with outstanding characteristics could be promising candidates for applying new generation fragrant materials in biomedicine, leather and the textile industry.

Liquid chromatographic study of two structural isomeric pentacyclic triterpenes on reversed-phase stationary phase with hydroxypropyl-β-cyclodextrin as mobile phase additive

Retention behavior of two structural isomeric pentacyclic triterpenic acids, maslinic acid and corosolic acid, was investigated by reverse phase high performance liquid chromatography (HPLC) with hydroxypropyl-β-cyclodextrin (HP-β-CD) as mobile phase additive. Inclusion complexation of maslinic acid, corosolic acid with hydroxypropyl-β-cyclodextrin was evaluated under different concentration of hydroxypropyl-β-cyclodextrin. Apparent formation constant (Km) between methanol and hydroxypropyl-β-cyclodextrin was determined to be 13.82 L mol−1 under 25 °C using UV-spectrophotometry. Two retention models were employed individually for evaluation of inclusion complexation between the two pentacyclic triterpenic acids and hydroxypropyl-β-cyclodextrin. It was found that a higher apparent formation constant (Kf) for corosolic acid and hydroxypropyl-β-cyclodextrin was obtained, 19115 L mol−1, indicating that a greater affinity of hydroxypropyl-β-cyclodextrin with corosolic acid was produced compared with that of maslinic acid, 11775 L mol−1, in the selected mobile phase, and stoichiometric ratio for both of inclusion complex was found to be 1:1. Thermodynamic analysis showed that a negative standard enthalpy change (ΔH) and an entropy change (ΔS*) for analyte transfer were obtained, where ΔH of maslinic acid and corosolic acid was found to be −10.188 kJ mol−1 and −10.650 kJ mol−1, ΔS* of two compounds was −2.092 and −2.180, respectively, indicating that transfer of structural isomers from mobile phase to stationary phase was enthalpically driven. Meanwhile, positive values were obtained for standard enthalpy change and standard entropy change, 136 kJ mol−1 and 274 kJ mol−1 and 536 J mol−1 K−1and 1004 J mol−1 K−1, for inclusion complexation between maslinic acid, corosolic acid and hydroxypropyl-β-cyclodextrin, while negative values were obtained for Gibbs free energy during formation of inclusion complex, −160 kJ mol−1 and −299 kJ mol−1, indicating a spontaneous inclusion reaction happened.

Effect of Slag Modification on Inclusions in Si–Mn‐Killed 304 Stainless Steels

Herein, plant trials are conducted to investigate the effect of slag modification on inclusions in Si–Mn‐killed 304 stainless steels. The slag basicity has a significant influence on inclusion compositions in 304 stainless steels. The Al2O3 content in inclusions shows a slight increase tendency with the slag basicity of 1.9. The addition of CaO increases the slag basicity from 1.9 to 2.2, which is beneficial to the removal of inclusions while increasing the Al2O3 content in inclusions from roughly 20% to 40%. The low slag basicity lowers the Al2O3 content in inclusions to around 20% while resulting in a higher total oxygen (TO) at the ladle furnace (LF) end. A kinetic model of slag–steel–inclusion reactions is developed to simulate the effect of slag modification on inclusion composition using FactSage Macro Processing. Evolutions of slag, steel, and inclusions during the slag modification process are well predicted.

Increased Photocatalytic Activity of Post Synthetically Modified Coordination Polymer Derived from Bis‐pyridyldiamide

A one‐dimensional looped chain coordination polymer (CP1) is synthesized by the reaction of CoII with N1,N3‐di(pyridine‐4‐yl)isophthalamide. Transmetalation reaction of CP1 with CuII showed single‐crystal‐to‐single‐crystal (SC‐SC) transformation to form CP2, which is also a 1D looped chain. Both CP1 and CP2 showed the presence of DMF as guest molecules near the loops of the 1D chains. CP1 and CP2 were found to have bandgap of 2.41 eV and 1.30 eV, respectively, which were calculated by Tauc plot. The difference observed in the optical bandgap of CP1 and CP2 is reflected in photocatalytic dye degradation studies. It was observed that CP2 showed much greater efficiency in degrading the dyes (Methylene blue, Methyl orange and Rhodamine B) as compared to that of CP1. The polar nature of the loops of the chains in CP1 and CP2 due to the presence of DMF was exploited to study the adsorption and desorption of I2. Adsorption of I2 in CP1 and CP2 was found to follow first order kinetics with a rate constant of 8.32 × 10–5 s–1 for CP1 and 9.71 × 10–5 s–1 for CP2. Guest inclusion reaction was performed to incorporate benzotriazole in the CP1. Impedance measurements showed a higher conductivity in the benzotriazole incorporated CP1.

Study on the preparation of geranyl acetone and \u03b2-cyclodextrin inclusion complex and its application in cigarette flavoring

β-Cyclodextrin (β-CD) inclusion complex containing geranyl acetone as a guest was prepared by saturated water solution method. Furthermore, the structure and properties of the inclusion complex were studied. The formation of the inclusion complex was demonstrated by. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-RD), thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The thermodynamic analysis of the inclusion complex showed that the inclusion reaction is an endothermic spontaneous reaction. The average of △H, △S and △G is 11.66 kJ mol−1, 0.082 kJ mol−1 and − 14.49 kJ mol−1, respectively. Moreover, the kinetic analysis of thermal decomposition of the inclusion compound showed that the thermal decomposition reaction is a first-order reaction (the inclusion ratio is 1:1), the average activation energy of the reaction is 180.90 kJ mol−1, and the binding force in the inclusion compound is mainly Van der Waals force. The flavor test of cigarettes showed that the inclusion compound improved the stability of geranyl acetone and the sensory quality of cigarettes. This study improves the solubility and thermal stability of geranyl acetone, and provides theoretical support and technical guidance for expanding the application of geranyl acetone.

Outgrower schemes and sugar value-chains in Zambia: Rethinking determinants of rural inclusion and exclusion

Abstract Integration of smallholders in outgrower schemes has been advanced as a strategy for poverty reduction in the global south, but how terms and conditions of inclusion and exclusion shape divergent outcomes, and processes underpinning these local dynamics remain an under-researched area. This study, set in Zambia’s southern ‘sugarbelt’ region of Mazabuka, draws on two contrasting outgrower schemes to examine determinants of smallholder inclusion in sugar value-chains, and consider how various terms and conditions underpining inclusion shape various interests, reactions and pathways for value capture among different local groups. Our study reaveals terms and conditions are important in shaping divergent outcomes for smallholders included in sugar value-chains. It shows determinants of inclusion and exclusion are complex and go beyond market imperatives that are production related (structural) to include social-cultural dynamics (non-structural). The centrality of the paper points to lived realities and experiences for different groups and political reactions from below, underlining how socially contested intersection of global–local value-chain produces diverse but interdependent hierarchies of inclusion and exclusion. For an early stage in planning of outgrower schemes by state and non-state actors, recognition of the various social groups and their complex engagement and reactions to changes in land-use and land control will not only expose competing interests but should inform polices, institutions and investments to improve value-chain impacts. This paper hopes to contribute towards a more nuanced understanding of the complex engagement of smallholders in changes in land use and land control in developing countries in the era of land-grabbing.

Tracking Inclusions during Ladle Refining Using a Kinetic Model for the Compositions of Metal, Slag, and Inclusions

A mathematical kinetic model to predict the trajectory of chemical compositions of the molten steel, slag, and inclusions in the ladle metallurgy furnace was presented in a recent study. The model considered the following chemical processes: 1) the rate of slag–steel reaction; 2) the rate of supply of calcium during calcium treatment; and 3) the rate of steel–inclusion reactions, including oxides and sulfides. Herein, the model is further validated by running the model in varying conditions and comparing the predicted and measured composition of inclusions and dissolved species in the steel for additional plant heats. A sensitivity analysis is also carried out to investigate the effect of different parameters, including sulfur content of steel, total oxygen, slag composition, and reoxidation of steel on the trajectory of composition of inclusions during the ladle process. The model developed by the authors offers potential for control and optimization of the operation of a ladle furnace.

Inclusion Complex of O-phthalaldehyde-Buprofezin with Dimethyl-β-Cyclodextrin Using Thermochemically-Induced Fluorescence Derivatization (TIFD) Method and its Analytical Application in Waters.

Improvement of the TIFD method to determine buprofezin (BUP) founded on the O-phthalaldehyde (OPA)-thermoproduct complex of buprofezin (OPA-BUP) with dimethyl-β-cyclodextrin (DMβCD) was investigated at 25°C. The TIFD method developed in DMβCD medium, was optimized with respect to the reaction time, DMβCD concentration and pH. Based on the inclusion reaction, the OPA-BUP: DMβCD inclusion complex was developed in two aqueous media pH7 and pH13. A 1:1 stoichiometric ratio of OPA-BUP: DMβCD complex was obtained. The binding constants (K) and Gibbs energy (ΔG°) values increasing and decreasing with pH, respectively, show the spontaneous and thermodynamically favorable at 25°C of the inclusion complexes formation. Normalized TIFD spectra were measured at 425nm for emission and at 345nm for excitation. Limits of detection (LOD) and quantification (LOQ) obtained, according to the pH, were in the ranges 0.05-0.1ng mL ̶ 1 and 0.2-0.4ng mL ̶ 1, respectively. Relative standard deviation (RSD) values, less than 1.3% corroborated TIFD method repeatability in DMβCD medium. Solid phase extraction (SPE) procedure which was used for quantitative analysis of natural water samples collected from Niayes area, led to satisfactory recovery rates values 99.5-117.3%.

Preparation and characterization of spherical titania and their influence on self-cleaning and anticorrosion properties of acrylic resin

Firstly, spherical TiO2 particles of micro-nano size were prepared by using the inclusion reaction product which resulted from the chemical reaction between urea and EtOH and the inclusion reaction product served as a template. The size of spherical TiO2 can be regulated by the ratio of urea solution. The spherical TiO2 particles are mainly composed of anatase. Then the above spherical TiO2 particles were used to enhance the properties of acrylic resin. With the increase of TiO2, the microstructure surface of TiO2/acrylic resin coating was in the uneven shape of lotus leaf. When the addition of TiO2 reaches up to 30 wt.%, it can enhance the anti-corrosion properties of the acrylic resin coating brushed on Q235 steel plate, the water contact angle on the surface of TiO2/acrylic resin coating is 121.5° and displays good self-cleaning properties in the water with sand whose concentration reaches 20 wt.%. The composite coatings exhibited the highest 5B rating determined by adhesion test ASTM D-3359-02 (American Society for Testing and Materials).

Binding, and thermodynamics of β-cyclodextrin inclusion complexes with some coumarin laser dyes and coumarin-based enzyme substrates: a simulation study

This paper addresses modelling the nature of interactions between β-CD and some coumarins including recently reported novel sulphur analogues to form inclusion complexes of appealing medicinal, photochemical and photophysical properties. The binding energy and the total stabilization energy (EONIOM) are used to confirm the most favorable inclusion complex structure. Thermodynamic parameters reveal exothermic inclusion reaction in gas phase. Thermal stability of fluorescent enzyme substrate of coumarin nucleus increases in the order: gas < cyclohexane < water, indicating better stability in water. Furthermore, molecular characteristics such as optimized geometries, MO’s and electrostatic potential energy map surfaces and energies are reported and correlated with some reactivity indices. Our results validated the experimentally available data reported in the literature. Inclusion complexes of β-CD with coumarins should result in improving its laser efficiency in environmentally benign aqueous medium.

Alkali endohedrals of C24(BN)12 heterofullerenes: A DFT aqueous phase study

AbstractResults achieved by density functional theory have been reported in terms of the energetic, electronic, vibrational frequencies, and thermochemical functions related to alkali metal endohedral derivatives of C24(BN)12 heterofullerenes in gas and aqueous phases. The endohedral heterofullerene cations are regarded as highly polar structures in both gas and aqueous phases. They indicate thermochemically approved solvation in the aqueous phase. The inclusion reactions are exothermic and spontaneous in the aqueous solution except for K+ cation. The calculated standard reduction potentials of alkali cation endohedral derivatives suggest them as potent oxidizing agents.

Interfacial effect of cyclodextrin inclusion complex on gas adsorption kinetics of dry water emulsion

Cyclodextrins (CD) solutions were mixed with hydrophobic SiO2 powders to form a dry-cyclodextrin-water (DCD) emulsion, and the effects of CDs with different concentrations and structures on gas adsorption kinetics were investigated, respectively. α-CD was found to enhance effectively both CH4 and CO2 gases adsorption capacity of DCD, while β-CD was generally negative to guest gas adsorption with one exception related to CH4 under lower concentration. Through analyzing dual interfacial effect of gas inclusion, the dominant competition between gas hydration and gas inclusion was speculated as the main reason for the different CD concentration dependence for CH4 and CO2 adsorption kinetics. Furthermore, based on considering the cooperative control of gas diffusion, hydration reaction, inclusion reaction and inclusion sedimentation, a diffusion-reaction-blocking model was suggested to describe the kinetic process. CH4 gases were found to prefer to exist in DCD with free form, while CO2 gases with adsorption form mainly. The selectiveness closely related to guest gas further illustrated the ‘CD concentration quenching’ appearing in CO2 adsorption rather than CH4 adsorption.

Kinetic study on compositional variations of inclusions, steel and slag during refining process

A steel-slag-inclusion-alloy-refractory-air multiphase model, which combined the kinetic analysis and the consideration of fluid flow in argon-stirred ladle, was established to investigate the compositional changes during refining process. The steel-slag reaction, the steel and inclusion reaction, the refractory-steel reaction, the refractory dissolution into the slag, the reoxidation of the molten steel, the removal of inclusions by floating, and the alloy dissolution were all considered in the current model. The stirring energy, the average speed of the molten steel in the plume, the horizontal speed of the molten steel in the open eye, the speed of the molten steel near the side wall, the speed of the molten steel at the bottom of the ladle and the volume fraction of the plume were obtained by mathematical simulation. The mass transfer coefficient of the molten steel is obtained by mathematical simulation. Meanwhile, it is assumed that the mass transfer coefficient of inclusions is influenced by the temperature. The calculation results are in accordance with the experimental ones. The influence of different slag compositions, different gas flow rates, and different inclusion diameters on system compositions were also investigated using the current model. It is indicated that the content of T.O. in the molten steel was influenced by the gas flow rate and the removal rate of inclusions goes up with the increasing inclusion diameter.