Magnesium Reduction Research Articles

Enhancing physico-chemical water quality in recycled dairy effluent through microbial consortium treatment

The dairy industry, notorious by generating wastewater rich in organic and nitrogenous content, necessitates sustainable recycling solutions. Biological treatment emerges as a cost-effective and chemical-free alternative. This study delves into the potential of microbial consortium, a microbial consortium, for recycling dairy effluent, aiming at water reclamation and environmental sustainability. Effluent samples from Madurai's Dairy Industry underwent microbial consortium treatment in a recycling prototype, with treatment efficacy assessed through physicochemical parameters and contaminant removal efficiency.Guided by a biodegradability index of 4.51, the study showcased EM's impact, revealing a notable decrease in pH levels, fostering an alkaline environment (2.35 ± 0.06 ppt). Dissolved oxygen increased significantly to 4.50 ppm, indicating improved aerobic conditions. EM treatment led to substantial reductions in calcium (53 %), magnesium (95 %), nitrogen (22 %), sulfate (79 %), phosphate (86 %), BOD (78 %), and COD (82 %). In contrast, dairy effluent treated without microbial consortium during the sludge activation process exhibited negligible water quality improvement.These findings underscore microbial consortium efficacy in advancing biological treatment of dairy effluent, demonstrating a significant reduction in contaminants and showcasing its potential for sustainable water reclamation. Improved alkalinity, dissolved oxygen, and nutrient content further signify positive impacts on ecosystem health. Microbial consortium emerges as a promising avenue for recycling dairy effluent, offering an economically viable and environmentally friendly solution. The study emphasizes the crucial role of microbial treatments in achieving efficient water reclamation, contributing to a cleaner and sustainable environment. Future research and broader implementation of microbial consortium in dairy industry wastewater management are recommended for enhanced environmental benefits.

Photothermal therapy and cell imaging tracking of porous silicon nanoparticle by magnesiothermic reduction and surface modification

The synthesis of silicon nanoparticles (PSi NPs) from silica nanoparticles (SiO₂) via magnesium (Mg) reduction is a promising technique due to its simplicity and cost-effectiveness. In this study, silica is utilized as the primary precursor and is subjected to a reduction process using magnesium powder as the reducing agent. By covalently attaching Fluorescein Isothiocyanate (FITC) to the surface of PSi NPs, we aim to enhance their fluorescence intensity and stability while also improving their surface reactivity and biocompatibility. The modified PSi NPs system was characterized using various microscopic techniques, Raman spectra, porosity and morphology analysis, Zeta potential, and analysis of organic functional groups to confirm successful conjugation and to evaluate changes in surface morphology, fluorescence properties, and colloidal stability. By leveraging the inherent photothermal conversion efficiency of PSi NPs, we explore their capacity to generate localized heat upon near-infrared (NIR) light irradiation, effectively inducing cancer cell apoptosis. Concurrently, the natural fluorescence of PSi NPs is harnessed to enable high-resolution imaging, facilitating real-time tracking and monitoring of therapeutic processes. The PSi NPs were subjected to a series of in vitro experiments to assess their photothermal efficiency, cytotoxicity, and imaging capabilities. Results demonstrate that PSi NPs exhibit excellent photothermal effects, leading to significant cell death in targeted cancer cells upon NIR exposure, while their fluorescence properties provide clear and detailed imaging. These findings highlight the potential of PSi NPs as multifunctional agents in cancer therapy, combining effective photothermal treatment with non-invasive imaging, thereby enhancing the precision and efficacy of therapeutic interventions.

Study on heat transfer enhancement mechanism of silicon carbide material applied to thermal magnesium reduction process

The refractory steel retort used in the thermal magnesium production industry works in a high temperature of 1200 °C under high vacuum condition for a long time, with a service life of only about 2 months. Frequent replacement of the reduction retort results in high production costs for thermal magnesium production. The fundamental reason for the instability and deformation of refractory steel reduction retort is high temperature creep, while silicon carbide material has very strong creep resistance and high thermal conductivity at high temperature. Therefore, the silicon carbide material is introduced into the field of thermal magnesium production in this paper. Based on the structural size of the traditional reduction retort, the silicon carbide straight fin reduction retort is designed, and the coupling characteristics of heat and mass transfer and chemical reaction in the silicon carbide straight fin reduction retort are studied by numerical calculation. The results show that the silicon carbide straight fin reduction retort can effectively improve the pellet temperature rise rate, and the minimum temperature in the initial stage is about 700 °C higher than that of the traditional refractory steel retort. The average magnesium production rates of the silicon carbide straight fin reduction retort with 2, 3 and 4 fins are 4.81, 5.89 and 6.91 kg/h, respectively, which are 37 %, 68 % and 97 % higher than that of the traditional retort with 3.5 kg/h. To further improve the production efficiency, a silicon carbide double loop straight fin reduction retort was designed, and the energy saving, emission reduction and carbon reduction potential of this silicon carbide double loop straight fin reduction retort used in thermal magnesium production industry was quantitatively analyzed. The average magnesium production rates of the silicon carbide double loop retort with a fin height of 150 mm and a fin number of 6, 8 and 12 are 5, 5.88 and 8.93 kg/h respectively, which increased the production efficiency by 43 %, 68 % and 155 % respectively compared with the traditional retort. The overall effect of increasing fin height and number on magnesium production rate was to prolong the peak time of production, so that most of the magnesium production work was completed in a short time. The research results in this paper provide a scientific basis for the application of silicon carbide materials in thermal magnesium production industry and a new way for energy saving and carbon reduction.

A novel magnesium reduction technique for the separation of ytterbium from non-aqueous solutions

The separation of heavy rare earth elements, particularly Tm, Yb, and Lu, poses significant challenges due to their small differences in ionic radii and close chemical properties. Utilizing the variable valence properties of ytterbium can simplify the separation from adjacent elements. Therefore, a novel magnesium reduction technique was proposed, offering selective reduction and separation of ytterbium. In comparison to traditional methods such as sodium amalgam reduction and mercury cathode reduction, this approach achieves efficient separation of ytterbium and lutetium without the need for mercury, rendering it more environmentally friendly and safe. Under a non-oxidizing nitrogen atmosphere, utilizing magnesium powder as the reducing agent and a mixed solution of 1,4-dioxane and ethanol as the reaction solvent, only 20 min are required to complete one reduction-precipitation operation for simulated solutions. This yields a recovery of 70.89% and a purity of 97.5% for ytterbium (II) chloride. The optimal experimental conditions obtained are applied to natural heavy rare earth mixed solutions, resulting in the recovery of over 90% of ytterbium after three reduction-precipitation processes. Post-ytterbium separation, the residual solution is enriched with approximately three times the amount of thulium and lutetium, greatly facilitating subsequent separation processes. This method liberates ytterbium reduction-separation from dependence on mercury, offering not only rapid and efficient processing but also significant industrial prospects.

Soil Acidification Can Be Improved under Different Long-Term Fertilization Regimes in a Sweetpotato-Wheat Rotation System.

Soil acidification is a significant form of agricultural soil degradation, which is accelerated by irrational fertilizer application. Sweetpotato and wheat rotation has emerged as an important rotation system and an effective strategy to optimize nutrient cycling and enhance soil fertility in hilly areas, which is also a good option to improve soil acidification and raise soil quality. Studying the effects of different fertilization regimes on soil acidification provides crucial data for managing it effectively. An eight-year field experiment explored seven fertilizer treatments: without fertilization (CK), phosphorus (P) and potassium (K) fertilization (PK), nitrogen (N) and K fertilization (NK), NP fertilization (NP), NP with K chloride fertilization (NPK1), NP with K sulfate fertilization (NPK2), and NPK combined with organic fertilization (NPKM). This study focused on the soil acidity, buffering capacity, and related indicators. After eight years of continuous fertilization in the sweetpotato-wheat rotation, all the treatments accelerated the soil acidification. Notably, N fertilization reduced the soil pH by 1.30-1.84, whereas N-deficient soil showed minimal change. Organic fertilizer addition resulted in the slowest pH reduction among the N treatments. Both N-deficient (PK) and organic fertilizer addition (NPKM) significantly increased the soil cation exchange capacity (CEC) by 8.83% and 6.55%, respectively, compared to CK. Similar trends were observed for the soil-buffering capacity (pHBC). NPK2 increased the soil K+ content more effectively than NPK1. NPKM reduced the sodium and magnesium content compared to CK, with the highest magnesium content among the treatments at 1.60 cmol·kg-1. Regression tree analysis identified the N input and soil magnesium and calcium content as the primary factors influencing the pHBC changes. Structural equation modeling showed that the soil pH is mainly influenced by the soil ammonium N content and pHBC, with coefficients of -0.28 and 0.29, respectively. Changes in the soil pH in the sweetpotato-wheat rotation were primarily associated with the pHBC and N input, where the CEC content emerged as the main factor, modulated by magnesium and calcium. Long-term organic fertilization enhances the soil pHBC and CEC, slowing the magnesium reduction and mitigating soil acidification in agricultural settings.

Silicon/carbon nanotubes anode for lithium-ion batteries: Synthesis, interface and electrochemical performance

Silicon/carbon composite has been a promising anode material for lithium-ion batteries (LIBs). Carbon nanotubes (CNTs) possess high electrical conductivity, specific area, and mechanical strength, holding great potential for constructing advanced Si/C anode materials. However, the unstable interface and tricky synthesis processes hinder practical applications of Si/CNTs anode. In this work, we develop a one-step method to prepare Si/CNTs composite by magnesium reduction of SiO2 mixed with CNTs. The interface between Si nanoparticles and CNTs upon the weight ratio of SiO2 to CNTs and their influences on the electrochemical performances of Si/CNTs composite have been systematically studied. The Si nanoparticle partly reacts with CNTs and forms Si-C bonds in the interface when the mass ratio of SiO2 to CNTs is above 1.5. The electrochemical performance of this three-phase heterostructure (Si/CNTs-2) are significantly improved due to the Si-C chemical bonding. A high initial reversible capacity of 1100.2 mAh g−1 at 0.2 A g−1 is obtained, and the capacity of 922.4 mAh g−1 remains after 200 cycles with a high capacity retention of 83.3 %. The rate capability is excellent and the capacity is 797 mAh g−1 at 5 A g−1 and remains 612.3 mAh g−1 after 1000 cycles. The interfacial design of Si/CNTs composite provides guidance to prepare high- performance Si/C composite anode.

Методы и применение интенсификации фиторемедиации сточных вод горнодобывающей промышленности

The article presents the latest results of research on the biological treatment of mining and metallurgical industrial wastewater using higher aquatic plants: Eichhornia (Eichhornia crassipes Solm) and Pistia (Pistia stratiotes L). The features of these plants detected during contaminated wastewater treatment have been identified. The primary results of experiments are based on single-stage treatment processes that ensure efficient wastewater treatment upon completion of plant adaptation to these waters. However, the duration of the process is long, i.e., 15–30 days; therefore, the process intensification experiments have been conducted. Experiments conducted within a week have achieved significant reductions in calcium, magnesium, sulfate, and chlorine ions. During the first days of the experiments, the plants continued to grow and develop, but due to high salt concentrations, some of the plants (approximately 50–60 %) died due to insufficient time for adaptation. The remaining plants were slowly recovering and continued vegetation. These plants have demonstrated high cumulative and treatment effects as they are considered most adapted to the chemical composition of wastewater. The use of such plants, however, will require longer periods for wastewater treatment, namely around a month, which does not comply with the production requirements. Therefore, a decision to experiment during 24 hours has been made. The results of the analysis have shown that the plants completely absorb calcium, magnesium, chlorine, nitrates, zinc, and cobalt already on the first day of planting; bicarbonates and sodium are absorbed on the second day; and iron on the third day. Potassium, manganese, arsenic, and thiocyanates are neutralized during 7–10 days. The average efficiency of wastewater treatment per day is 51% on the condition of frequent renewal of the plant biomass. Based on the results obtained, a biotechnology built on a multi-stage biological wastewater treatment system of industrial scale has been developed.

Changes in pharmacist’s recommendations of over-the-counter treatments for the common cold during the COVID-19 pandemic

BackgroundThe common cold is one of the most frequently occurring illnesses worldwide. The aim of this study was to determine which OTC anti-common cold medications were most often recommended by pharmacists and if the COVID-19 pandemic affected such recommendations. MethodsNon-interventional, observational research trial using a self-developed questionnaire to collect data on pharmacists’ recommendations for anti-common cold OTC treatment. The data were collected during the COVID-19 pandemic (December 2021-February 2022) in four large community network pharmacies in Lodz (Poland) and then compared with an analogue period of time before the pandemic (December 2019-February 2020). ResultsDuring COVID-19 pandemic there was a significant (p < 0.05) reduction in paracetamol, acetylsalicylic acid, metamizole magnesium, inosines, alpha-mimetics, mucolytics, homeopathics, and sore throat products and an increase in other tablets/capsules and add-on product recommendations. There was a significant relationship (p < 0.05, OR > 1) between the recommended frequency of paracetamol, inosines, sore throat products (each symptom), metamizole magnesium (headache, fever), acetylsalicylic acid (headache, fever, fatigue), NSAIDs, alpha-mimetics (headache, rhinorrhea), pseudoephedrine (rhinorrhea), homeopathics (headache), herbal products (fatigue), antihistamines (rhinorrhea, cough), and mucolytics (headache, fever, cough). ConclusionsFavorable prices (before COVID-19 pandemic) and reports on common NSAIDs side effects (beginning of the pandemic) led to high sale of paracetamol. Increased awareness of clinical effectiveness of some medications or their reduced availability influenced their limited recommendations.

Chemical composition and sensory characteristics of fermented condiments produced from soybean, bambara nut and pigeon pea seeds blends

This study evaluated the chemical composition and sensory characteristics of fermented condiments produced from blends of soybean, bambara nut and pigeon pea. The soybean, bambara nut and pigeon pea fermented using banana leaves were formulated and designated as 100:0:0 (SBPB), 60:25:15 (SBPB1), 40:35:25 (SBPB2), 20:45:35 (SBPB3) and 10:55:35 (SBPB4), where sample SBPB served as the control. Proximate, mineral and sensory properties of the condiments were determined using standard methods. The proximate results showed significant (p&lt;0.05) differences among the samples. The mineral results indicated increase in calcium, iron, zinc and reduction in magnesium and potassium with higher proportion of bambara nut and pigeon pea in the blend. Sensory evaluation results showed significant (p&lt;0.05) differences in texture, appearance and overall acceptability, with sample SBPB4, containing 10% soybean, 55% bambara nut and 35% pigeon pea recording the highest scores for all the attributes assessed. Therefore, nutritious and acceptable fermented condiments can be produced from the blends of soybean, bambara nut and pigeon pea.

Comprehensive investigation of the impact of milling time on microstructural evolution and tribological properties in Mg-Ti-SiC hybrid composites

This research delves into the effects of milling time on the properties of Mg-Ti dual matrix composites reinforced with nano SiC powders, processed via spark plasma sintering. The study, driven by the need for advanced materials with enhanced wear resistance for the aerospace and automotive sectors, focuses on microstructural evolution and wear characteristics. It aims to understand how varying milling durations influence particle morphology, crystallite structure, and consequently, tribological behavior. Initial observations indicate a decrease in average particle size to 5.72 µm, followed by an increase to 14.83 µm due to cold welding and particle trapping, demonstrating the dynamic nature of particle morphology under different milling conditions. X-ray diffraction analysis reveals a notable reduction in magnesium's crystallite size with increased milling, suggesting plastic deformation. This study underscores that smaller crystallite sizes do not always correlate with strain, especially in smaller dimensions. Additionally, the research records variations in density and hardness, influenced by milling time and particle dispersion, with hardness showing a complex variation, peaking at 108 HV. Overall, the findings highlight the critical role of milling duration in shaping the microstructure and determining the mechanical and wear properties of Mg-Ti-SiC composites. This investigation contributes to the optimization of wear resistance in these composites, enhancing their applicability in high-performance industrial applications.

Coordination and Activation of N2 at Low-Valent Magnesium using a Heterobimetallic Approach: Synthesis and Reactivity of a Masked Dimagnesium Diradical.

The activation of dinitrogen (N2) by transition metals is central to the highly energy intensive, heterogeneous Haber-Bosch process. Considerable progress has been made towards more sustainable homogeneous activations of N2 with d- and f-block metals, though little success has been had with main group metals. Here we report that the reduction of a bulky magnesium(II) amide [(TCHPNON)Mg] (TCHPNON = 4,5-bis(2,4,6-tricyclohexylanilido)-2,7-diethyl-9,9-dimethyl-xanthene) with 5% w/w K/KI yields the magnesium-N2 complex [{K(TCHPNON)Mg}2(μ-N2)]. DFT calculations and experimental data show that the dinitrogen unit in the complex has been reduced to the N22- dianion, via a transient anionic magnesium(I) radical. The compound readily reductively activates CO, H2 and C2H4, in reactions in which it acts as a masked dimagnesium(I) diradical.

Effects of magnesium reduction in artificial low-salinity water on the growth of Pacific white shrimp Litopenaeus vannamei in a biofloc system

Intensive shrimp production in salinized waters proposes to supply fresh seafood away from the coast. However, the high prices of specific salts, such as magnesium chloride, excessively increase costs, impairing financial returns. A 77-day study was conducted to evaluate the effects of reductions in magnesium [Mg2+] concentrations and magnesium: calcium ratio (Mg2+: Ca2+) of artificial seawater at salinity 5 g L−1 on the zootechnical performance of shrimp in the nursery and grow-out phases in a biofloc system. The experiment was composed of five treatments and three repetitions each, with the Mg2+: Ca2+ ratios of 3:1, 2:1, 1:1, 0.5:1, and 0.1:1. Both phases were carried out in 40 L tanks. In the nursery, post-larvae (0.017 ± 0.001 g) were stocked at a density of 1500 m−3 and reared for six weeks until they reached approximately 1.2 g. Grow-out was carried out at a density of 500 m−3 for five weeks. Water quality parameters, major ion composition, and zootechnical performance were evaluated during the experiment. The evolution of the concentrations of total ammoniacal nitrogen, nitrite‑nitrogen, and nitrate‑nitrogen in the 0.1:1 treatment showed different behaviors compared to the other treatments throughout the experimental period. At the end of the nursery and grow-out phases, Mg2+ concentrations in the 0.1:1 treatment were 26.6 ± 2.1 mg L−1 and 7.1 ± 1.0 mg L−1, respectively. In the nursery, final weight, food conversion ratio (FCR), and yield were affected in the 0.5:1 and 0.1:1 treatments compared to the control. In grow-out, FCR, yield, and survival were affected at the 0.1:1 ratio. In addition to low [Mg2+], high nitrite and nitrate concentrations were responsible for the low growth and survival at the 0.1:1 ratio. The study showed that it is possible to reduce [Mg2+] and the Mg2+: Ca2+ to approximately 30 mg L−1 and 1:1, respectively, in a biofloc system without affecting shrimp performance.

AZ91 alloy nanocomposites reinforced with Mg-coated graphene: Hot-pressing sintering, heat-treatment and microstructure

Graphene has been successfully coated with the nano-Mg through organic magnesium reduction method. The nano-Mg coated graphene (GNPs) was further processed into AZ91 magnesium matrix composites through hot-pressing sintering. The effects of different solution and aging heat treatment on the microstructure evolution and interface bonding of GNPs reinforced AZ91 composites with a content of 2.5 wt% were investigated. The results show that with the increase of GNPs content, the average grain size of the composites decreases gradually, and different forms of β-Mg17Al12 precipitates in the microstructure can heterogeneously nucleate on GNPs. Compared with T4, T5 heat treatment, after T6 heat treatment, a large number of strengthening eutectic phase (β-Mg17Al12) was precipitated in the composite, which promoted the formation of a three-dimensional interlocking tight bonding structure at the GNPs-Mg interface and significantly enhanced the interface bonding strength. During the T6 heat treatment, dynamic recovery and recrystallization occurred in the composites. The area fraction of angle grain boundary increases, and the recrystallization area fraction increases from 24.49% to 75.72%. The texture intensity is obviously weakened, and the maximum texture intensity is reduced from 5.01 to 3.37.

Thermodynamic Justification of Obtaining Ferroalloy from a Mixture of Chrysotile-Asbestos Waste and Carbonaceous Rock

The results of research on the thermodynamic prediction of obtaining ferroalloys with the reduction and distillation of magnesium from a mixture of chrysotile-asbestos waste produced by Kostanay Minerals JSC and carbonaceous rock are presented. The research was carried out by thermodynamic modelling methods using the HSC-6.0 Chemistry software package of the Finnish metallurgical company Outokumpu based on the principle of the Gibbs minimum energy and a rotatable second-order plan (the Box-Hunter plan). Based on the conducted studies on the distribution of Si, Al, Mg between the condensed and gas phases, it was found that the formation of ferrosilicoaluminum of the FS45A10 brand with a content of 7.5-10.1% Al and 42.5-44% Si occurs in the presence of 25-25.9% iron at 1959-2000°C; ferrosilicon of the FS45 brand with a content of 41.0-44.4% Si and &lt; 2.5% Al is formed in the temperature range of 1800-1877°C in the presence of 25.4-35% iron. In addition to branded ferrosilicon and ferrosilicoaluminum, it is possible to obtain Fe-Si-Al ligatures containing 2.5-10.1% Al and 41.0-44.7% Si from a mixture of chrysotile-asbestos production wastes and carbonaceous rock. In the presence of 25

Constructing 3D cross-connected networks in spongy MgO/Ni/MWCNT composites to synchronously boost microwave absorption and thermal conductivity

To address the issues of electromagnetic (EM) radiation and waste heat engendered in modern electrics, we pioneer the utilization of 3D cross-connected MgO/Ni/MWCNT networks as a magnetic-dielectric-dual-loss filler with electron-phonon dual thermal carriers to synchronously boost EMW absorption and thermal conductivity. The carbothermic reduction of magnesium oxalate/nickel oxalate core-shell hexahedra produced from a cryogenic precipitation/precipitate transfer route causes the in-situ self-catalytic growth of MWCNTs on the surfaces of porous MgO/Ni composites. The component, microstructure, and texture of the composites and their resulting performance can be tuned by some dynamic factors (i.e., [Ni2+], Ts, etc.). The spongy MgO/Ni/MWCNT composites formed under [Ni2+] = 1.6 M and Ts = 600 ℃ exhibit the optimal EMW absorption and thermal conductivity. Compared with the most previously reported materials, they have a larger thermal conductivity (3.61 W/(m⋅K)), a larger EAB/d value (∼4.61 GHz/mm), stronger absorption (−51.33 dB), and a smaller thickness (1.7 mm). The synchronously enhanced properties are attributed to magnetic/dielectric dual losses, electron/phonons dual thermal carriers, and 3D interconnected networks in MgO/Ni/MWCNT composites, which generate the strong attenuation, good low-frequency matching performance, and continuous heat transfer path. Noteworthy, spongy MgO/Ni/MWCNT composites are promising as a multifunctional filler to address the issues of EMI and thermal dissipation.

Optimization of Rock Salt Washing Process to Remove Selected Chemical Impurities in Lake Katwe Rock Salt

Rich deposits of mineral salts, present in substantial economic quantities, characterize the geological bounty of Uganda. The primary location of this wealth is lake Katwe, a saline crater lake southwest of the country. However, all grades of rock salt extracted from Lake Katwe remain contaminated with chemical impurities such as calcium, magnesium, heavy metals and sulphate ions, even after solar evaporation process from the salt pans. There is a need to conduct research into possible contaminant removal methods which could increase the market value of the extracted salt, and add to the body of knowledge for future salt processing and chlor-alkali industries in Uganda. This study examined the effect of varying water volumes and temperature on the levels of Calcium, Magnesium and Sulphate ions in rock salt samples from Lake Katwe. The samples were methodically crushed and washed. The salt was then dissolved, crystallized, dried and meticulous analysis to determine the concentration of these impurities was carried out. The data was analysed and represented in Microsoft Excel and MATLAB. Results obtained revealed that a temperature of 40°C and salt-water ratio of 1:2 are the optimal parameters for maximum reduction of calcium, magnesium and sulphate impurities in rock salt. This analysis enhances the purity of salt harvested from Lake Katwe’s solar evaporation process and offers optimal washing parameters to reduce impurities in brine, thereby improving plant yield and reducing production costs across various salt grades. It also provides new information to the mining communities at Lake Katwe on how to affordably improve the percentage purity of their rock salt. The study will also contribute novel industry-tailored data for future prospective salt processing and chlor-alkali industrial plants near the Lake while also filling a knowledge gap for further research on rock salt purification.

Study of the effect of regenerative heat transfer enhancement on the silicothermic reduction process

As the main process for industrialized production of crude magnesium, the silicothermic reduction technology has problems such as high energy consumption per ton of magnesium and serious pollution. Under the policy of carbon peak and carbon neutrality, the implementation of energy conservation and pollution reduction technology reform has become an urgent issue in the silicothermic reduction process. Although the thermal conductivity of the briquettes used for magnesium production is low, they will absorb a lot of heat during the reduction reaction. As a result, the heat cannot be transferred quickly enough for the chemical reaction endothermic, leading to a slow magnesium production reaction and low production efficiency. Therefore, in-depth study on the kinetic mechanism of the improved heat transfer coupled chemical reaction is required to decrease the production cycle and increase efficiency. In this work, the effect of filling the voids of briquettes with regenerative particles of different materials on heat transfer process was first studied by means of experiments. It has been discovered that as the thermal conductivity of the filling material increases, the heat transfer process is accelerated, but the endothermic behavior of the regenerative particles at room temperature during the heating process seriously affects the heat transfer to the briquettes. On this basis, the models of heat transfer and magnesium reduction kinetics were combined and the recycling technology of high temperature regenerative particles with different materials was studied by numerical calculation method. The findings demonstrate that the production cycles for filling aluminum oxide, silicon carbide and silicon nitride are reduced to 6, 4 and 1 h, respectively, at the initial temperature of 1373 K for the regenerative particles, compared with the 8 h of the traditional method. However, when the voids of the briquettes are filled with quartz sand with a thermal conductivity close to that of the briquettes, the period increases to more than 10 h. When the initial temperature of the filled regenerative particles decreases, the production cycle also increases. In industrial production, materials with high thermal conductivity should be selected as regenerative particles as far as possible on the basis of considering the cost, and thermal insulation measures should be taken to minimize the heat loss during the recycling of regenerative particles.

Deoxygenative Cross-Coupling of C(aryl)–O and C(amide)═O Electrophiles Enabled by Chromium Catalysis Using Bipyridine Ligand

Deoxygenative cross-coupling between unactivated C–O and unsaturated C═O electrophiles remains an unsolved challenge in synthetic chemistry. Here, we report the deoxygenative cross-coupling of C–O/C═O electrophiles by reaction of unactivated aryl esters with unsaturated amides, enabled by chromium catalysis. Inexpensive and simple CrCl3 salt combined with bipyridine ligand, magnesium reductant, and chlorosilane, shows high reactivity in promoting the deoxygenative coupling between C–O and C═O bonds involving hydrogen transfer. This reaction provides a strategy to form pharmaceutically interesting diarylmethylated amines, by forging C(sp2)–C(sp3) bonds with impeding the competing ester homocoupling and carbonyl reduction that usually occur under reductive conditions. Mechanistic studies based on high-resolution mass spectrometry analysis and deuterium-labeling experiments indicate that cleavage of ester C–O bonds by Cr and subsequent silylation leads to the formation of arylated silachromate, which regioselectively adds to carbonyls of amides through reductive elimination and deoxygenative hydrogen transfer, resulting in the reductive cross-coupling of C(aryl)–O and C(amide)═O electrophiles.

Interfacial engineered PANI/carbon nanotube electrode for 1.8 V ultrahigh voltage aqueous supercapacitors

Flexible three-dimensional interconnected carbon nanotubes on the carbon cloth (3D-CNTs/CC) were obtained through simple magnesium reduction reactions. According to the Nernst equation, the cell voltage based on these pure carbon electrodes without any additives could reach 1.5 V due to the higher di-hydrogen evolution over potential in neutral 3.5 M LiCl electrolytes. In order to improve the electrochemical performance of the electrodes, 3D-CNTs/CC electrodes covered with polyaniline barrier layer (3D-PANI/CNTs/CC) were prepared by in situ electropolymerization using interfacial engineering method. The assembled symmetric supercapacitors display a broadened voltage of 1.8 V, high areal capacitance of 380 mF cm−2, outstanding areal energy density of 85.5 μWh cm−2 and 84% of its initial capacitance after 20 000 charge-discharge cycles. This work demonstrated that the interface engineering strategy provides a promising way to improve the energy density of carbon-based aqueous supercapacitors by widening the voltage and boosting the capacitance simultaneously.

Impact of radiotherapy on the morphological and compositional structure of intra-radicular dentin

Considering the side effects in the oral cavity and dental structures of radiotherapy (RDT) for head and neck cancer, this study aimed to evaluate the effects of RDT on the root dentin concerning the obliteration of dentinal tubules, the inorganic composition of intra-radicular dentin, and the integrity of collagen fibers. Thirty human canines were selected from a biobank and randomly divided into two groups (n=15). The samples were sectioned buccolingually, and a hemisection was used for structural analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Low-vacuum SEM images were obtained at 2000-x magnification to observe the obliteration of the dentinal tubules. Moreover, compositional evaluation was performed using EDS. After RDT, the SEM and EDS analyses were repeated using the same methodology. RDT was applied fractionally at 2 Gy per day, 5 days per week, for 7 weeks, resulting in a total dose of 70 Gy. The collagen integrity of the irradiated and non-irradiated samples was analyzed using Masson's trichrome and picrosirius red staining polarization microscopy. Samples subjected to RDT exhibited dentinal tubule obliteration (p < 0.001); low integrity of type I and III collagen fibers (p < 0.05); compositional reduction of calcium (p = 0.012), phosphorus (p = 0.001), and magnesium (p < 0.001); an increased Ca/P ratio (p < 0.001). RDT affects the structure of dentinal tubules, the inorganic composition of intra-radicular dentin, and the collagen fiber integrity in the root dentin, which may interfere with the effectiveness and durability of dental procedures.