Charge Calculation Research Articles

Copper, Iron and Aluminium Electrochemical Corrosion Investigation during Electrolysis and Temperature Increasing

An experimental method to calculate average charge of metal ions by electrolysis at different temperatures is proposed. Aluminium undergoes dissolution to the Al3+ ions at all temperatures. Iron undergoes dissolution to the Fe2+ or the Fe3+ ions and copper undergoes dissolution to the Cu+ or the Cu2+. It depends on temperature and electric current density. Direct electric current value and anode mass decreasing were measured during electrolysis into concentrated NaCl solution in water (5 mol/kg or 23.1%, freezing point equals -22°C, pH 6.5–7.5) at room temperature and 100°C. The average charges of copper, iron, and aluminium ions were calculated using Faraday’s law of electrolysis at electric current density 3,000 A/m2 (or 30 A/dm2): +3 for aluminium; +2 for iron; and +1 for copper at room temperature, and +3 for aluminium; +2 for iron; and +1.5 for copper at temperature 100°C. The main condition was zAl=3. We concluded that calculations of the average metal ions charges, zFe and zCu, were correct since zAl=3. The result is as follows: the Al3+, the Fe2+, and the Cu+ ions dissolve into concentrated NaCl solution in water at room temperature; the Al3+, the Fe2+, the Cu+ and the Cu2+ ions (50%/50%) dissolve into the solution at temperature 100°C. We have obtained experimentally and by mathematical modelling that aluminium anodes (cylindrical or spherical) dissolve into the solution more rapidly with temperature increasing during electrolysis accordingly to the Arrhenius law, while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180°C like “inverse Arrhenius law”. Iron electrochemical corrosion rate practically does not depend on temperature below 100°C (and, obviously, up to 180°C) like “zeroth Arrhenius law”. The spherical anode effect is greater than the cylindrical anode effect in 1.5 times.

β-Bi2O3-Bi2WO6 Nanocomposite Ornated with meso-Tetraphenylporphyrin: Interfacial Electrochemistry and Photoresponsive Detection of Nanomolar Hexavalent Cr.

Hexavalent chromium exposure via inhalation, ingestion, or both has been proven to adversely affect internal organs, induce toxic effects, cause allergies, and contribute to the development of cancer. It requires a substantial and challenging effort to detect several heavy metal ions conveniently, sensitively, and reliably by using materials that are easy to synthesize and have a high yield. The impact of light on the electrocatalytic oxidation/reduction process proves an environmentally friendly methodology with numerous applications in pollution control. The extensive use of photoactive materials in photoelectrochemical (PEC) sensors necessitates the development of stable and highly effective photoactive materials. Hence, the solvothermal synthesis of the organic-inorganic hybrid nanocomposite β-Bi2O3-Bi2WO6/H2TPP with varying weight percentages of meso-tetraphenylporphyrin (H2TPP) resulted in a selective electrode for electrocatalytic and photoelectrocatalytic reduction of Cr6+ on fluorine-doped tin oxide (FTO) by an adsorption-reduction mechanism. H2TPP increases the active site density and provides an effective surface area for efficient adsorption by providing both pyridinic- and pyrrolic-N atoms to β-Bi2O3-Bi2WO6/H2TPP. H2TPP could effectively adsorb Cr6+ in the β-Bi2O3-Bi2WO6/H2TPP composite system through electrostatic interaction, and the adsorbed Cr6+ ions were reduced to trivalent chromium Cr3+, resulting in promising Cr6+ sensing. The projected density of states and Bader charge calculations result in the electrostatic attraction among the N-2p orbital of H2TPP and the 3d and 4s orbitals of the Cr atom, resulting in the adsorption of the hexavalent Cr atom onto the active center of H2TPP. Moreover, the addition of H2TPP results in the development of a mesoporous surface that offers strong electrical conductivity, a substantial surface area, improved charge-mass transport, intimate contact between the electrolyte and catalyst, an extended fluorescence lifetime, and increased stability. The role of pH values was thoroughly investigated. All electrochemical and photoelectrochemical studies were carried out on 5 wt % H2TPP-ornated β-Bi2O3-Bi2WO6. Nanocomposite β-Bi2O3-Bi2WO6/5 wt % H2TPP demonstrated reliable cyclic stability, reproducibility, good sensitivity (8.005 μA mM cm-2), and a low limit of detection (LOD) (8.0 nM) toward photoelectrocatalytic reduction of Cr6+. The interference study in the presence of a few inorganic entities exhibited excellent selectivity. This tale amplification approach for developing a β-Bi2O3-Bi2WO6/5 wt % H2TPP nanocomposite system suggests a deeper understanding of the application of photoelectrocatalytic reduction of Cr6+ in environmental remediation with real samples under light irradiation.

Development of Ti4O7 reactive electrochemical membrane and electrochemical oxidation of naphthols in aqueous solution

Naphthols (NAPs), commonly used phenolic compounds, have significant impact on environmental risk and human health, necessitating advanced treatment methods for their degradation. In this study, a Ti4O7 reactive electrochemical membrane (REM) was developed for the electrochemical oxidation of NAPs. The Ti4O7 REM presented a porosity of 42.18 ± 2.3% and a median pore diameter of 1.21 µm. High permeability (846 LMH bar−1) was achieved at relatively low transmembrane pressure and resulted in a convection-enhanced rate constant for Fe (CN)64- oxidation of 1.7 × 10−4 m/s. The increase in current density and decrease in plate spacing had a positive influence on NAPs degradation. The TOC removal efficiencies of 1-naphthol (1-NAP) and 2-naphthol (2-NAP) were 68.6% and 63.5%, respectively at the current density of 6 mA/cm2 and plate spacing of 10 mm. Additionally, quantum chemical calculation using density functional theory (DFT) was employed to identify the active sites of NAPs through atom charge and frontier electron density (FED) calculations. Results showed that C14 and C10 were identified as the active sites for 1-NAP, while C9 and C13 were the active sites for 2-NAP. Hydroxyl radical and sulfate radical produced on the electrode surface were the main oxidants for NAPs degradation during the electro-oxidation process. The degradation pathway included hydroxylation, oxygenation, decarbonylation, and ring-open processes, which was in agreement with the theoretical calculations. Furthermore, the quantitative structure-activity relationship (QSAR) predictive model was used to assess the toxicity changes during the electrochemical oxidation process of NAPs, suggesting that the toxicity of intermediates increased at the beginning and significantly reduced at the end. This comprehensive study provides practical and theoretical insights into the application of electrochemical oxidation technique for the reduction of refractory compounds in wastewater.

Self-consistent calculations of the electric charge, ion drag force, and the drift velocity of spherical grains using Langevin dynamics and comparisons against canonical experiments

We present trajectory simulation-based modeling to capture the interactions between ions and charged grains in dusty or complex plasmas. Our study is motivated by the need for a self-consistent and experimentally validated approach for accurately calculating the ion drag force and grain charge that determine grain collective behavior in plasmas. We implement Langevin dynamics in a computationally efficient predictor–corrector approach to capture multiscale ion and grain dynamics. Predictions of grain velocity, grain charge, and ion drag force are compared with prior measurements to assess our approach. The comparisons reveal excellent agreement to within ±20% between predicted and measured grain velocities [Yaroshenko et al., Phys. Plasmas 12, 093503 (2005) and Khrapak et al., Europhys. Lett. 97, 35001 (2012)] for 0.64, 1.25 μm grains at ∼20−500 Pa. Comparisons with the measured grain charge [Khrapak et al., Phys. Rev. E 72, 016406 (2005)] under similar conditions reveal agreement to within ∼20% as well. Measurements of the ion drag force [Hirt et al., Phys. Plasmas 11, 5690 (2004); IEEE Trans. Plasma Sci. 32, 582 (2004)] are used to assess the viability of the presented approach to calculate the ion drag force experienced by grains exposed to ion beams of well-defined energy. Excellent agreement between calculations and measurements is obtained for beam energies >10 eV, and the overprediction below 10 eV is attributed to the neglect of charge exchange collisions in our modeling. Along with critical assessments of our approach, suggestions for future experimental design to probe charging of and momentum transfer onto grains that capture the effect of space charge concentration and external fields are outlined.

Enhanced Interface with Strong Charge Delocalization toward Ultralow Overpotential CO2 Electroreduction

The construction of an interface has been demonstrated as one of the most insightful strategies for designing efficient catalysts toward electrochemical CO2 reduction (CO2RR). However, the weak interfacial interaction and inherent instability inevitably hinder a further performance enhancement in CO2RR attributable to the interface effect. Herein, 2 nm Ag nanoclusters (Ag NCs) are embedded onto CeO2 nanospheres (CeO2 NSs) with highly interconnected porosity (Ag NCs@CeO2 NSs) to exclusively study the pure interface effect toward CO2RR. The enhanced Ag–CeO2 pure interface endows Ag NCs@CeO2 NSs with a remarkably larger current density, significantly higher Faraday efficiency (FE), and energy efficiency as compared to Ag NCs, CeO2 NSs, and the one with Ag NCs dispersed on CeO2 nanoparticles. More importantly, an impressively high CO FE of over 70.0% is achieved at an ultralow overpotential (η) of 146 mV. The free energy and differential charge calculations, coupled with X‐ray photoelectron spectroscopy results jointly imply that the effective initiation of CO2RR to CO at a lower η over Ag NCs@CeO2 NSs derives from the enhanced interface‐induced charge delocalization, which enhances the electron transfer ability toward *COOH intermediate, thus overcoming the energy barrier demanded for the rate‐determining step.

Effect of different pseudopotentials on the phonon frequencies, dielectric constant, and Born effective charge of SnSe and SnSe2 nanostructures: A density functional perturbation theory study

The choice of the pseudopotentials (PPs) is a crucial step towards an accurate atomistic calculation of physical properties of 2D materials. In this study, based on Density-Functional Perturbation Theory (DFPT), we investigated the dependency of the phonon properties such as phonon frequencies, dielectric constant, Born effective charge, and vibrational modes of SnSe and SnSe2 monolayers to the different types of PPs. On the basis of Generalized Gradient Approximation (GGA) using PBE functional, we computed eight phonon calculations for both lattices in combinations with four different PPs including Normconversing (NC) FHI/HGH, Ultrasoft (USPP), and Standard Solid-State (SSSP), while other parameters like cut-off energy, k-points mesh, and convergence threshold were kept fixed. However, the phonon properties of acoustic and optical phonons were better predicted by USPP and SSSP for phonon dispersion of SnSe and SnSe2, respectively. Regarding the dielectric constant and Bohr effective charge calculations, our results showed that SnSe and SnSe2 structures possess the dielectric tensor of 8.9 and 6.6 along the in-plane direction by using USPP calculations. Our outcomes also revealed less sensitivity of SnSe2 polarization to the type of PPs by applying the electric field. This study recommends USPP and SSSP to further phonon analysis of other semiconductors.

Iron, copper, and aluminium electrochemical corrosion in motionless and moving electrolytes investigation during electrolysis

An experimental method to calculate average charge of metal ions by electrolysis at different temperatures is proposed. Aluminium undergoes dissolution to the Al3+ ions at all temperatures. Iron undergoes dissolution to the Fe2+ or the Fe3+ ions and copper undergoes dissolution to the Cu+ or the Cu2+. It depends on temperature and electric current density. Direct electric current value and anode mass decreasing were measured during electrolysis into concentrated NaCl solution in water (5 mol/kg or 23.1 %, freezing point equals −22 °C, pH 6.5–7.5) at room temperature and 100 °C. The average charges of copper, iron, and aluminium ions were calculated using Faraday's law of electrolysis at electric current density 3000 A/m2 (or 30 A/dm2 = 3 mA/mm2): +3 for aluminium; +2 for iron; and +1 for copper at room temperature, and +3 for aluminium; +2 for iron; and +1.5 for copper at temperature 100 °C. The main condition was zAl = 3. We concluded that calculations of the average metal ions charges, zFe and zCu, were correct since zAl = 3. The result is as follows: the Al3+, the Fe2+, and the Cu+ ions dissolve into concentrated NaCl solution in water at room temperature; the Al3+, the Fe2+, the Cu+ and the Cu2+ ions (50 %/50 %) dissolve into the solution at temperature 100 °C. We have obtained experimentally and by mathematical modelling that aluminium anodes (cylindrical or spherical) dissolve into the solution more rapidly with temperature increasing during electrolysis accordingly to the Arrhenius law, while copper anodes (cylindrical or spherical) dissolve more slowly with temperature increasing from room temperature to temperature 180 °C like “inverse Arrhenius law”. Iron electrochemical corrosion rate practically does not depend on temperature below 100 °C (and, obviously, up to 180 °C) like “zeroth Arrhenius law”. The spherical anode effect is practically the same as the cylindrical anode effect. The galvanic current dependence on ratio of cathodic surface area to anodic surface area in the system Fe-chromium (Cr) stainless steel and the time of the iron anodes dissolution in motionless electrolyte and in moving electrolyte are also analysed using literature experimental data.

Computational Investigation of the Intermolecular Interactions between Decatungstate Acid and CX2O (X=H, F, Cl, and Br)

AbstractThis study explores intermolecular interactions between the polyoxometalate (POM) compound, decatungstate acid, and CX2O (X=H, F, Cl, and Br). Initial optimizations were conducted using the PBE0 and M06‐2X /Lanl2DZ level of theory, renowned for adsorption studies. Computational results revealed a notable sequential increase in binding affinity for reactive compounds on POM surfaces optimized with PBE0, TPSSH, M06‐2X, CAM‐B3LYP, and ωB97XD/Lanl2Dz methods. Interestingly, the findings indicated a high binding affinity between reactive compounds and POM surfaces, affirming M06‐2X functional suitability for studying decatungstate acid interactions. Additionally, adsorption energy (Eads) values were negative, indicating stable adsorption processes. Careful examination of quantum theory of atoms in molecules (QTAIM), natural charge calculations, and hybridization calculations unveiled impressive intermolecular interactions, with non‐covalent interactions (NCIs) revealing deep blue iso‐surfaces in (CH2O@POM) and (CF2O@POM) complexes, indicating significant electrostatic force of interaction and presence of hydrogen bond interactions, enhancing POM surface‘s gas interaction capacity and smooth sensing. The analyzed complexes displayed slight increases in HOMO‐LUMO energy gap compared to POM, with the order of increase as follows: CH2O@POM (0.0819 eV)>CF2O@POM (0.0772 eV)>CBr2O@POM (0.0747 eV)>CCl2O@POM (0.0705 eV), suggesting POM′s suitability as an adsorbent. The study‘s major findings reveal the effective adsorption of CBr2O and CH2O facilitated by hydrogen bond interactions on the POM surface, making decatungstate acid a potential adsorbent for removing polluting gases from the atmosphere.

Modulating metal-oxygen interactions of high-entropy oxide electrocatalysts enables highly-active and ultra-stable water oxidation

High-entropy oxide (HEO) electrocatalysts are appealing for multi-step catalytic reactions as their high compositional diversity and multi-element synergy effects. Herein, we find that the metal-oxygen (M-O) interactions in FeCoNi-based HEO can be well-optimized by introducing Al and Ce elements. The in-situ electrochemistry-triggered Al leaching exposes abundant newly-formed active sites with greatly reduced energy difference between TM 3d and O 2p orbitals. This fact shows the enhancement of M-O covalency, which is further quantified by the Fe/Co/Ni charge calculations. The stronger M-O covalency greatly decreases the activation energy of water oxidation at Fe/Co/Ni sites and the barrier of electrical transfer. Furthermore, the Ce element downshifts the O 2p band center, effectively refraining lattice oxygen loss. These advantages enable a supersmall overpotential of 303.7 mV at 500 mA cm−2 that maintains 95.8 % even operating for 840 h, which is the best report for the HEOs to date.

Self-Adjustment Strategies of International Chain Hotels in Surabaya during the New Normal Era

The Covid-19 pandemic severely impacted Indonesia's tourism industry, resulting in a sharp decline in hotel room occupancy rates in Surabaya. To recover, hotels adopted strategies. This article examines how hotels affiliated with international brand networks coped with the pandemic. The study focuses on Quest Hotel and Holiday Inn Express Surabaya CenterPoint, both renowned for their star ratings and business hotel concept in the city centre. Research revealed a significant drop in room occupancy rates during the pandemic. Strategies included strict adherence to health protocols, salary adjustments without altering service charge calculations, limited use of hotel facilities, showcasing health and cleanliness certifications on promotional materials, flexible booking periods, room price promotions, and non-room product sales. These measures aimed to prioritize guest safety, increase revenue, and adjust to the pandemic's impact. Implementing these adaptations, the hotels aimed to position themselves for recovery and success in the new normal era.

Voltammetric analysis of mephenoxalone drug in pharmaceutical and biological samples using novel screen-printed sensor with boron-doped diamond electrode

A novel screen-printed sensor (SPE) with boron-doped diamond electrode (BDDE) for determination of a muscle relaxant and mild anxiolytic mephenoxalone (MNL) was developed. The sensor utilizes the electrochemical oxidation of MNL, which was firstly studied in aqueous solution using oxygen terminated BDDE. MNL provided an irreversible anodic signal at a potential of + 1380 mV (vs. Ag/AgCl/KCl sat.) over a wide pH range. Britton-Robinson buffer (pH 9) was selected as a suitable electrolyte and the square-wave voltammetric method (SWV) was developed. The low detection limit (55 nmol L–1), wide linear dynamic range (0.1–30 µmol L−1), and good recovery in the analysis of model and pharmaceutical samples (RSD < 1.77%) were attained. Subsequently, the new method was successfully transferred to SPE, which can find application in point-of-care testing. These sensors proved excellent sensitivity and reproducibility in the analysis of biological samples (RSD < 4.94%) without pretreatment and no need of electrolyte. Based on gas chromatography with mass spectrometry (GC-MS) analysis of preparative electrolysis products, a mechanism of the electrochemical oxidation of MNL was proposed, describing the oxidative cleavage of the alkoxybenzene ring. These results were supported with HOMO spatial distribution calculations and atomic charges calculations for arising radical cations, and with spectroelectrochemical measurements.

Ab initio study of electronic structure, bonding and optical properties of ternary A2B2In (A = Ca, Eu and B = Pd, Pt) indides

Crystal structure, optical and electronic properties of metal rich intermetallic Ca2Pd2In, Ca2Pt2In, Eu2Pd2In and Eu2Pt2In compounds have been explored using density functional theory based orthogonalized linear combination of atomic orbitals (OLCAO) method and code. The local density approximation scheme has been employed to probe all the properties. The outcomes of the electronic structure revealed the conducting nature of ternary indides. Density of states plots of ternary indides exhibited an increased number of energy states moving from Ca2Pd2In, Ca2Pt2In, Eu2Pd2In to Eu2Pt2In at Fermi level which substantiate the metallic nature of these compounds. The localization index calculations reflected the highly delocalized states in the vicinity of Fermi level. The cationic behavior of Ca- and Eu-atoms and anionic character of Pd-, Pt-, In-atoms has been evaluated through the effective charge (Qα*) calculations. Bond order calculations indicated highest strength of Ca2Pt2In among the studied indides. Optical features in the form of complex dielectric function, optical conductivity and electron energy loss function have been thoroughly discoursed. Two eminent peaks in electron energy loss L(ω) spectra have been observed at 29.77 and 27.83 eV which are associated to the plasmonic resonance.

A 3,5-dinitropyridin-2yl Substituted Flavonol-based Fluorescent Probe for Rapid Detection of H2S in Water, Foodstuff Samples and Living Cells.

A novel flavonol-based fluorescent probe, Fla-DNT, has been synthesized for the rapid and specific detection of H2S. Fla-DNT exhibits excellent selectivity and anti-interference properties, a short response time (4min), large Stokes shift (138nm), and low detection limit (1.357 µM). Upon exposure to H2S, Fla-DNT displays a remarkable increase in fluorescence intensity at 542nm. Meanwhile, the recognizing site of H2S was predicted through Electrostatic potential and ADCH charges calculations, while the sensing mechanism of H2S was determined via HRMS analysis and DFT calculation. More importantly, the probe owes multiple applications, such as a recovery rate ranging from 92.00 to 102.10% for detecting H2S in water samples, and it can be fabricated into fluorescent strips to track H2S production during food spoilage by tracking color changes, thereby enabling real-time monitoring of food freshness. The bioimaging experiments demonstrate the capability of Fla-DNT to detect both endogenous and exogenous H2S in living cells. These results provide a reliable method and idea for H2S detection in complex environments.

Selective, rapid extraction of uranium from aqueous solution by porous chitosan–phosphorylated chitosan–amidoxime macroporous resin composite and differential charge calculation

Herein, a new porous chitosan–phosphorylated chitosan–amidoxime macroporous resin composite (PCAR) was designed and synthesized for the rapid and selective extraction of uranium resources from aqueous solution. This study showed that PCAR exhibited excellent adsorption toward uranium in a pH range of 5–9. The dynamic adsorption process aligned with the quasi-second-order kinetic model and corresponded to the chemical adsorption process. The maximum adsorption capacity was 561.28 mg·g−1 at pH 6 and 308 K. Mechanism analysis showed that the synergistic effect of the amidoxime group (−(NH2)C=N–OH), PO, and –NH2 on the PCAR surface improved the uranium adsorption performance. The differential charge density indicated that the amidoxime and phosphate groups provide lone-pair electrons for the adsorption of UO22+ and their synergistic effect improves the UO22+ adsorption performance of PCAR. The uranium distribution coefficients of PCAR and CAR are 4.6 and 2.4 times those of vanadium, respectively. These results indicate that phosphorylation can ameliorate the disadvantage of competitive vanadium adsorption of the amidoxime adsorbent. In addition, PCAR exhibits good reusability and stable adsorption capacity after five adsorption–desorption cycles. Hence, PCAR has excellent potential for uranium extraction from aqueous solution.

Does Lidocaine Shorten Seizure Duration in Electroconvulsive Therapy?

Electroconvulsive therapy (ECT) is an effective short-term treatment for schizophrenia and depression, amongst other disorders. Lidocaine is typically added to reduce pain from intravenous propofol injection. However, depending on the dose used in the ECT setting, it can shorten seizure duration. The aim of this study was to investigate the effect of lidocaine dose on seizure duration. This retrospective, naturalistic cohort study included 169 patients treated with ECT. We examined 4714 ECT sessions with propofol or propofol plus lidocaine. Ictal quality was manually rated by visual inspection. The main outcome of this study was the relation of lidocaine with seizure duration after controlling for socio-demographic, ECT, and other anesthetic variables. There was a significant negative association between lidocaine usage and seizure duration. Multivariate analyses showed that seizure duration was shortened by an average of 3.21 s in sessions with lidocaine. Moreover, in this subgroup, there was a significant negative dose-dependent association between lidocaine dose and seizure length. Complementarily, a significant positive association between preictal BIS and seizure length was found in the subgroup of sessions where preictal was used. We provide additional evidence highlighting the importance of caution regarding lidocaine dosing due to the effect on seizure length in the ECT setting. It is advisable for clinicians to exercise caution when administering lidocaine regarding its dosing and seizure length in ECT settings. Future investigation is needed to assess causal relationships by studying certain vulnerable groups or employing other charge calculation techniques, such as the titration method.

Tailor-designed nanoparticle-based PdNiSn catalyst as a potential anode for glycerol fuel cells

In order to effectively use glycerol as a fuel in direct glycerol fuel cells, a catalyst that can break the C–C bond and enhance the electro-oxidation of glycerol to CO2 is necessary. In this particular investigation, a palladium-nickel-tin nanocomposite electrodeposited on a glassy carbon electrode (PdNiSn/GC) exhibited excellent activity towards the electro-oxidation of glycerol, thanks to the synergistic effect of the catalyst composition. The PdNiSn/GC surface generated a peak current (Ip) that was 2.5 times higher than that obtained at a Pd/GC electrode, with a cathodic shift in the onset potential (Eonset) of approximately 300 mV. Additionally, the current obtained at the PdNiSn/GC surface remained stable during continuous electrolysis. Capacitance measurements were used to interpret the results of the electrocatalytic activity, and high-performance liquid chromatography indicated that the products of the glycerol electro-oxidation reaction were oxalic acid and formic acid, which were subsequently oxidized to CO2, as revealed by the charge calculations. The results depict that the synergy between Pd, β-Ni(OH)2, and SnO2 is crucial for boosting GEOR through enhancing the C–C bond cleavage and completely oxidize the reaction intermediates to CO2.

Study of rock damage characteristics in decoupled slit charge blasting based on computer tomography scanning

Controlling blast load damage and destruction of the remaining rock mass in rock blasting has been the focus of scientific research. By studying various decoupling ratios of the slit charges, blasting experiments and numerical calculations of the small charge were carried out on the glauconite specimen. The internal fracture and damage characteristics of the damaged specimens (post blast) were quantified by computed tomography (CT) scanning and three-dimensional (3D) model reconstruction. The results showed that the damage to the glauconite specimens was mainly radial, with the main crack surface in the slit direction and the “X-type” and “Y-type” non-slit directions. With the increase in the decoupling ratio of the slit charge, the fractal dimension of the explosion crack face tends to increase, and the degree of damage gradually increased; When the decoupling ratio was 1.67, the fractal dimension of the explosive crack surface decreased, the smallest degree of damage. LS-DYNA simulation software was used to study the dynamic fracture process and the effective stress peak of the blasthole wall in the slit and non-slit directions for different decoupling ratios of the slit charge. The numerical calculation results showed that with the increase in the decoupling ratio, the peak effective stress of the blasthole wall characteristic unit in the slit direction was larger than that in the non-slit direction; The effective stress peak showed an increasing trend, and the maximum peak effective stress was 567.7 MPa when the decoupling ratio was 1.67. Therefore, this method can be a suitable means to reconstructing the spatial distribution of internal cracks and numerical calculation to evaluate the damage mechanism of slit charge blasting; Furthermore, within the range of the optimal slit charge decoupling ratio, this method can guide the site to prevent the damage and destruction of the remaining rock mass, allowing for more, allocation and utilization of the explosion energy.

A combined experimental and theoretical approach effect of Curcuma. L extract as a corrosion inhibitor on iron in acidic solution

ABSTRACT Inhibition performance of the aqueous Curcuma.L extract as a corrosion inhibitor for an iron surface in a 0.1 M HCl solution was investigated using the ac impedance technique. The inhibition efficiency for iron was determined in the presence of the Curcuma.L extract in a 0.1 M HCl solution and reached 81.1% at the optimum concentration. The corrosion inhibitive effect was achieved through the adsorption of Curcuma.L molecules onto the iron surface, which followed the Langmuir adsorption isotherm model. The inhibitive strength of the main compounds in the Curcuma.L extract, namely Curcumin (Inh A), demethoxycurcumin (Inh B), and bis-demethoxycurcumin (Inh C), might have a direct relationship with the electron-donating ability of the molecules, as revealed by quantum chemical parameters. Theoretical investigations were conducted using DFT methods with the B3LYP/6-311G++(d,p) basis set. Mulliken charge and ESP calculations were performed to illustrate the mechanism of inhibition of this extract on the iron surface. The interaction energies derived from Monte Carlo simulations followed the order Inh A > Inh B > Inh C. The aqueous extract of Curcuma.L has been shown to effectively inhibit iron corrosion in acidic environments.

One-dimensional longitudinal space charge calculation based on integrated green function approach

For fast longitudinal electron beam dynamics study or optimization in an x-ray free electron laser (FEL) linear accelerator, the one-dimensional longitudinal space charge (1D LSC) impedance, assuming a round cylinder beam with uniform transverse distribution is extensively used in both analytical analysis and numerical simulation. In this paper, instead of employing the impedance model in the frequency domain, we directly calculate the longitudinal electric field by convolving the longitudinal beam density with the slice green function, i.e., the longitudinal electric field generated by a slice beam. For high-energy electron beam, the slice green function rapidly diminishes to zero within a distance significantly smaller than the bunch length. In order to resolve the sharp variation, we report on a fast and high-precision method by applying the integrated green function (IGF) approach to compute the 1D LSC field numerically with few grid points, therefore, providing us with an alternative approach to the impedance model.

Photochemical Oxidation of Dimethyl Sulfide with Triplet Nitro Compounds

The mechanism of oxygen atom transfer between triplet molecules of a nitro compound and dimethyl sulfide is considered. This reaction pathway can be one of the possible routes in the reaction of photochemical oxidation of the sulfur compound. Quantum-chemical modeling has shown the feasibility of such a reaction as having a fairly low activation energy. The transition states of the reaction have almost the same structure in various solvents. The calculation of spin densities and charges on atoms in transition states hasshown no significant charge separation. This finding is also confirmed by calculation of the activation parameters of the oxygen transfer reaction involving various solvents. The activation energies remain almost unchanged with an increase in the solvent permittivity. All the data obtained suggest the radical mechanism of oxygen atom transfer with the participation of the triplet nitro compound.