Quintic trigonometric Bézier curve with two shape parameters

The fifth degree of trigonometric Bézier curve called quintic with two shapes parameter is presented in this paper. Shape parameters provide more control on the shape of the curve compared to the ordinary Bézier curve. This technique is one of the crucial parts in constructing curves and surfaces because the presence of shape parameters will allow the curve to be more flexible without changing its control points. Furthermore, by changing the value of shape parameters, the curve still preserves its geometrical features thus makes it more convenient rather than altering the control points. But, to interpolate curves from one point to another or surface patches, we need to satisfy certain continuity constraints to ensure the smoothness not just parametrically but also geometrically

Crystallization and Agglomeration Kinetics of Hydromagnesite in the Reactive System MgCl₂–Na₂CO₃–NaOH–H₂O

The reactive crystallization kinetics of hydromagnesite (4MgCO₃·Mg­(OH)₂·4H₂O) for the MgCl₂–Na₂CO₃–NaOH–H₂O system has been systematically investigated in a continuously operated mixed-suspension mixed-product removal (MSMPR) crystallizer for the first time. Determination of the effects of reactive temperature and OH^– ion on magnesium carbonate hydrates in the above system was conducted through a batch crystallization experiment, and the crystallization temperature of 80 °C for the precipitation of regular spherical-like hydromagnesite was selected for the kinetics study. The relative supersaturation for hydromagnesite is obtained based on the activity coefficients calculated by the Pitzer model. The growth rate, nucleation rate, and agglomeration kernel are determined on the basis of the agglomeration population balance equation, and their kinetic equations are then correlated in terms of power law kinetic expressions. The orders of volume growth rate and linear growth rate with respect to the relative supersaturation are 1.55 and 0.95, respectively. The magma density has an important effect on the nucleation rate of hydromagnesite particles. However, the expression of β ∝ <i>M</i>_T^–0.39 for hydromagnesite agglomeration shows that the magma density has a negative effect on the agglomeration kernel. All of these will provide a basis for the design and analysis of industrial crystallizers

Solubility and Self-Consistent Modeling of Aniline Hydrochloride in H–Mg–Na–Ca–Al–Cl–H₂O System at the Temperature Range of 288–348 K

Previous work has proved that the preparation method of anhydrous magnesium chloride by using the thermal decomposition of the complex [HAE]­Cl·MgCl₂·6H₂O is a potential process for commercial application. Normally, the complex [HAE]­Cl·MgCl₂·6H₂O is synthesized by reaction crystallization of aniline hydrochloride (C₆H₅NH₂·HCl, [HAE]­Cl) and bischofite (MgCl₂·6H₂O). The study on the solubility of [HAE]Cl in hydrochloric acid and various chloride salt solutions plays a significant role in the development, analysis, and engineering design for this new process. This work is a continuation of our systematic study of the solubility of [HAE]Cl in different chloride media. The solubility of [HAE]Cl in different concentrations of HCl (1.19–6.98 mol·kg^–1), NaCl (0.5–3.8 mol·kg^–1), CaCl₂ (0.5–4.5 mol·kg^–1), AlCl₃ (0.5–2.8 mol·kg^–1), and their mixed solutions was determined using a dynamic method in the temperature range from 288 to 348 K. With the purpose of improving AspenPlus’s prediction capability, in regard to [HAE]Cl solubility data in the H–Mg–Na–Ca–Al–Cl–H₂O systems at various temperatures, new model parameters were obtained via the regression of the experimental solubility of [HAE]­Cl in single electrolyte solutions, such as HCl, NaCl, CaCl₂, and AlCl₃, under atmospheric pressure. With the newly obtained electrolyte NRTL (ENRTL) interaction parameters for [HAE]­Cl–NaCl, [HAE]­Cl–CaCl₂, [HAE]­Cl–AlCl₃, and AlCl₃–H₂O, and default parameters for NaCl–H₂O and CaCl₂–H₂O in AspenPlus, a self-consistent model for the system [HAE]–H–Mg–Na–Ca–Al–Cl–H₂O was established with the maximum relative deviation of 4.3% between experimental and predicted solubility values

Elevated Atmospheric CO2 and Drought Affect Soil Microbial Community and Functional Diversity Associated with Glycine max

<div><p>Abstract Under the background of climate change, the increase of atmospheric CO2 and drought frequency have been considered as significant influencers on the soil microbial communities and the yield and quality of crop. In this study, impacts of increased ambient CO2 and drought on soil microbial structure and functional diversity of a Stagnic Anthrosol were investigated in phytotron growth chambers, by testing two representative CO2 levels, three soil moisture levels, and two soil cover types (with or without Glycine max). The 16S rDNA and 18S rDNA fragments were amplified to analyze the functional diversity of fungi and bacteria. Results showed that rhizosphere microbial biomass and community structure were significantly affected by drought, but effects differed between fungi and bacteria. Drought adaptation of fungi was found to be easier than that of bacteria. The diversity of fungi was less affected by drought than that of bacteria, evidenced by their higher diversity. Severe drought reduced soil microbial functional diversity and restrained the metabolic activity. Elevated CO2 alone, in the absence of crops (bare soil), did not enhance the metabolic activity of soil microorganisms. Generally, due to the co-functioning of plant and soil microorganisms in water and nutrient use, plants have major impacts on the soil microbial community, leading to atmospheric CO2 enrichment, but cannot significantly reduce the impacts of drought on soil microorganisms.</p></div

Experimental Study on the Molecular Hydrogen Release Mechanism during Low-Temperature Oxidation of Coal

Although H₂ gas is used in coal mines as an important indicator to reflect the state of coal spontaneous combustion, the gas production of H₂ at low temperature has been scarcely reported in the literature. In this paper, the modes and release mechanism of molecular hydrogen were investigated for three different coal ranks below 200 °C. Batch reactor tests were performed in combination with chromatographic analysis of the coal oxidation process. The experimental results showed that molecular hydrogen release mainly originated from coal oxidation rather than thermal decomposition of inherent hydrogen-containing groups. The amount of hydrogen released increased with the coal rank. The H₂ release process during low-temperature oxidation typically proceeds in two phases, namely H₂ slow release (<i>T</i> < 100 °C) and H₂ accelerated release (<i>T</i> > 100 °C) phases. Experiments with model compounds revealed aldehyde compounds to noticeably produce H₂. Coal plays a positive role in promoting the aldehyde groups to release H₂ and CO₂, but an opposite trend was observed in the case of CO. As revealed by Fourier transform infrared (FTIR) spectroscopy, the amount of aliphatic structures significantly decreased with the oxidation intensity, and a drastic increase in the aldehyde content was found at temperatures above 120 °C. Additionally, the path for the formation of H₂ during low-temperature oxidation of coal was provided

Phase Equilibrium Study of the AlCl₃–CaCl₂–H₂O System for the Production of Aluminum Chloride Hexahydrate from Ca-Rich Flue Ash

The study of the solid–liquid phase equilibrium for the AlCl₃–CaCl₂–H₂O system is of significance to separate aluminum chloride hexahydrate from the leachate obtained by the reaction of Ca-rich fly ash and a waste hydrochloride from chemical plant. The phase equilibrium data for the binary AlCl₃–H₂O system and the ternary AlCl₃–CaCl₂–H₂O system over the temperature range from 278.15 K to 363.15 K were measured. A rigorous and thermodynamically consistent model representing the AlCl₃–CaCl₂–H₂O system developed on the basis of the Pitzer’s activity coefficient model embedded in the Aspen Plus. On the basis of this, the phase behavior of the ternary AlCl₃–CaCl₂–H₂O system at different temperatures was visualized with lucidity on an equilateral triangle. The phase-equilibrium diagram generated by modeling was illustrated to identify the course of crystallization to recover AlCl₃·6H₂O from the solutions containing calcium chloride. All of these will provide a thermodynamic basis for the separation of aluminum chloride from calcium chloride solutions

Layered Cu₇(TeO₃)₂(SO₄)₂(OH)₆ with Diluted Kagomé Net Containing Frustrated Corner-Sharing Triangles

The half-spin Kagomé antiferromagnet is one of the most promising candidates for the realization of a quantum spin liquid state because of its inherent frustration and quantum fluctuations. The search for candidates for quantum spin liquids with novel spin topologies is still a challenge. Herein, we report a new diluted Kagomé lattice in Cu₇(TeO₃)₂(SO₄)₂(OH)₆, showing a 9/16-depleted triangle lattice, where the corner-sharing triangle units [Cu₅(OH)₆O₈] are separated by CuO₂(OH)₂. Magnetic measurements show that the title compound does not exhibit long-range antiferromagnetic order down to 2 K, suggesting strong spin frustration with <i>f</i> > 19

Layered Cu₇(TeO₃)₂(SO₄)₂(OH)₆ with Diluted Kagomé Net Containing Frustrated Corner-Sharing Triangles

The half-spin Kagomé antiferromagnet is one of the most promising candidates for the realization of a quantum spin liquid state because of its inherent frustration and quantum fluctuations. The search for candidates for quantum spin liquids with novel spin topologies is still a challenge. Herein, we report a new diluted Kagomé lattice in Cu₇(TeO₃)₂(SO₄)₂(OH)₆, showing a 9/16-depleted triangle lattice, where the corner-sharing triangle units [Cu₅(OH)₆O₈] are separated by CuO₂(OH)₂. Magnetic measurements show that the title compound does not exhibit long-range antiferromagnetic order down to 2 K, suggesting strong spin frustration with <i>f</i> > 19

Large Fluorescence Response by Alcohol from a Bis(benzoxazole)–Zinc(II) Complex: The Role of Excited State Intramolecular Proton Transfer

The formation of a bis­(HBO) anion is known to turn on the fluorescence to give red emission, via controlling the excited-state intramolecular proton transfer (ESIPT). The poor stability of the formed anion, however, hampered its application. The anion stability is found to be greatly improved by attaching the anion to Zn²⁺ cation (i.e., forming zinc complex), whose emission is at λ_em ≈ 550 and 760 nm. Interestingly, addition of methanol to the zinc complex induces a remarkable red fluorescence (λ_em ≈ 630 nm, ϕ_fl ≈ 0.8). With the aid of spectroscopic studies (¹H NMR, UV–vis, fluorescence, and mass spectra), the structures of the zinc complexes are characterized. The emission species is identified as a dimer-like structure. The study thus reveals an effective fluorescence switching mechanism that could further advance the application of ESIPT-based sensors

Flavone-Based ESIPT Ratiometric Chemodosimeter for Detection of Cysteine in Living Cells

We have designed and synthesized a novel ratiometric fluorescent chemodosimeter <b>MHF</b>-based ESIPT process for specific detection of cysteine among the biological thiols. The probe <b>MHF</b> shows very weak blue fluorescence under UV excitation. Upon addition of cysteine (Cys), the reaction of Cys with <b>MHF</b> induces acrylate hydrolysis, thereby enabling the ESIPT process to shift the weak blue emission to a strong green emission with about 20-fold enhancement. We utilized ¹H NMR spectra to elucidate the fluorescence sensing mechanism. Moreover, the cellular imaging experiment indicated the <b>MHF</b> possessed excellent selectivity, low cytotoxicity, and desirable cell permeability for biological applications