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Crucible Materials
Published in Nagaiyar Krishnamurthy, Metal–Crucible Interactions, 2023
Spinel refers to a group of minerals of the common structure AB2O4, where A represents a divalent cation and B a trivalent cation. The common trivalent cations are aluminium (Al+3), ferric iron (Fe+3) and chromium (Cr+3), and the divalent cations are magnesium (Mg+2) and ferrous iron (Fe+2).
Ignition Diagnostics in EGR- and Air-diluted Methane/Air Mixtures Using Spark Induced Breakdown Spectroscopy
Published in Combustion Science and Technology, 2022
Laura Merotto, Thomas Kammermann, Patrik Soltic
Natural gas-dedicated engines with stoichiometric or lean-burn combustion concepts are currently being developed to improve the thermal efficiency and take advantage of the lower CO2 emissions compared to gasoline and diesel, especially if renewable methane is used. The higher knock resistance of methane allows increasing the compression ratio compared to today’s bivalent engines in the passenger car sector, and it is important for emissions and knock control also in stationary engines. Nevertheless, methane leads to a more challenging environment to successfully initiate combustion, due to higher pressures at spark timing resulting in an increased demand on the insulation resistance on the coil and spark plug.
Syntheses, structures and fluorescence properties of a Zn and a Cd(II) coordination polymer based on the mixed ligands
Published in Inorganic and Nano-Metal Chemistry, 2022
Guilian Li, Weidong Yin, Gaojing Du, Jinyuan Zhang, Mengni Liu, Guangzhen Liu
The complex 1 crystallizes in monoclinic crystal system, P21/c space group and features a two-dimensional layer structure. The asymmetric unit contains one bivalent Zn cation, one 4-npa dianion and one btmb molecule, as shown in Figure 1a. The Zn(II) center is a distorted tetrahedral [ZnO2N2] coordinated by two carboxylate O atoms from two symmetry-related 4-npa dianions and two N atoms from two symmetry-related btmb ligands. The Zn–O bond lengths are 1.938(2) and 1.949(2) Å, and the Zn–N bond lengths are 2.013(3) and 2.040(2) Å, respectively.
Enhanced brilliant blue FCF adsorption using microwave-hydrothermal synthesized hydroxyapatite nanoparticles
Published in Journal of Dispersion Science and Technology, 2020
Yan Wang, Yiming Li, Yong Zhang, Wei Wei
The initial pH value of dye solution affects the chemical properties of dye molecular and adsorbent. It determines the surface charge and ionization degree of the adsorbent.[27,28] In this study, batch adsorption experiments were performed by changing the pH value of BBF solution from 3 to 8 at different ionic strengths. Figure 3 (left panel) displayed the influence of pH on the equilibrium adsorption capacity of BBF. From the figure, it can be seen that the adsorption capacity decreased gradually with the increase of pH at different ionic strengths. For example, the BBF adsorption capacity decreased from 10.2 to 5.7 mg/g when pH increased from 3 to 8 (0.1 mol/L KCl). It has been reported that BBF has sulfonate groups which can dissociate in aqueous solution depending on the pH of the solution, according to pKa values of 5.83 and 6.58, the BBF molecule appears as a bivalent or monovalent anion or in neutral form at different pH values.[29] As shown in Figure 3 (left panel), the adsorption of neutral chemical species of BBF was favorable at lower pH, while as the pH increases, the dissociation of the species increased and the adsorption decreased. Furthermore, the pHPZC of the prepared HAP was found to be 6.3 (Figure 3, right panel), which suggested that the positively charged HAP (pH < 6.3) could adsorb anionic BBF through electrostatic attraction. On the other hand, the negatively charged HAP (pH > 6.3) did not favor the adsorption of anionic BBF due to electrostatic repulsion. Similar results were also reported for the adsorption of BBF on hen feathers,[2] unmodified bentonite,[12] and mesoporous hybrid xerogel.[13] The detailed adsorption mechanism will be discussed in section 3.7.