Higher Reaction Time Research Articles

Error monitoring under working memory load: Anelectrocortical investigation.

Error monitoring is essential for detecting errors and may facilitate behavioral adjustments that can reduce or prevent future errors. At times, error monitoring must occur while individuals are engaged in other, cognitively demanding tasks that might consume processing resources necessary for error monitoring. Here, we set out to determine whether concurrent working memory (WM) load interferes with error monitoring, as measured using event-related potentials, the error-related negativity (Ne/ERN), and error positivity (Pe). Fifty-four participants (n = 33 female) completed an arrowhead flanker task, with trials presented under low (2 letter) or high (6 letter) WM load. Participants were required to hold letter strings in memory and to recall these letters at the end of a set of flanker trials. Results showed that WM load reduced the Pe but did not affect the Ne/ERN. Therefore, WM load appeared to attenuate later, more elaborated stages of error processing, though initial error detection was unaffected. Additionally, high WM load slowed reaction times overall, but did not lead to a significant increase in errors. As such, slower responses may have helped participants maintain comparable accuracy for low-load versus high-load trials. Overall, results indicate that WM load interferes with the evaluation of error significance, which could interfere with behavioral adaptations over time.

The synthesis of Fe3O4@SiO2-NNO-CuII nanocatalyst and investigation of its application in the synthesis of imidazo[1,2-a]pyridines

In this study, a tridentate Schiff base ligand obtained from the condensation of salicylaldehyde and 3-amino-1,2,4 triazole was covalently immobilized on the surface of 3-chloro-trimethoxysilane-functionalized magnetic nanoparticles. This nitrogen and oxygen-rich compound provides donor arms for the coordination of copper ions. The prepared nanocatalyst (Fe3O4@SiO2-NNO-CuII) has been characterized by various techniques including FT-IR, EDX, SEM, VSM, XRD and ICP analysis and used as an efficient recyclable catalyst for the synthesis of imidazo[1,2-a]pydidines. Imidazo[1,2-a]pyridine products were obtained through the coupling reaction of substituted benzaldehydes, 2-aminopyridine derivatives and phenylacetylene under solvent-free conditions in high yields and short reaction times.

Exploring gender differences in acoustic-thermal comfort and performance in a simulated working environment

This study investigated gender differences in acoustic-thermal comfort and cognitive performance in three workload levels in eight simulated work environments with two noise levels (55 and 75 dBA) and four air temperatures (18, 22, 26, and 30 °C). Subjective perceptions, including noise annoyance and fatigue, physiological measurements like Heart Rate Variability (HRV), respiration rate, and EEG variables (ALPHA, BETA, THETA) were used to assess comfort. In addition, the cognitive performance of men and women was evaluated on three levels: simple, medium, and complex. Women generally reported higher annoyance levels than men, especially at 75 dB noise level and increasing temperatures. Women experienced higher fatigue in warmer conditions than men. Women exhibited higher accuracy and lower reaction time than men at 18 °C and 22 °C with a quiet noise level (55 dBA) and simple and medium tasks. However, women acted accurately in complex tasks but had a higher reaction time. On the contrary, as the tasks are complicated and air temperature (26 °C and 30 °C) increases, men have higher accuracy and further reaction time than women. Accuracy and reaction time were diminished in both genders at 75 dBA noise level. Significant changes in the physiological parameters were observed at 18–22 °C for men and at 26–30 °C for women with the same noise level. Women had higher alpha and beta waves at 18–22 °C, indicating greater comfort and alertness, but these values decreased as air temperature rose. Overall, the study emphasizes the importance of considering gender differences when designing indoor work environments for optimal comfort and performance.

One pot multi-component synthesis of novel functionalized pyrazolo furan-2(5H)-one derivatives: in vitro, DFT, molecular docking, and pharmacophore studies, as coronavirus inhibitors.

New and facile one-pot approach for the syntheses of 12 derivatives of 3,5-disubstituted furane-2(5H)-one (4a-l) from easily available starting materials. The suitable synthetic procedures for selective synthesis of diverse furane-2(5H)-one derivatives were achieved via multi-component condensation of 1,3-diphenyl-1H-pyrazole-4-carbaldehyde (1), pyruvic acid and different aromatic amines 3a-l in good to high yields and short reaction time by refluxing in acetic acid as well as obtained by another method (method B) when unsaturated arylidene pyruvic acid 6 was refluxed with different aromatic amines in acetic acid but in smaller yield than method A. Structures of the prepared compounds were elucidated by elemental analysis and spectral data as mass, IR, 1H-NMR and 13C-NMR spectroscopy. The antiviral efficacy of compounds 4a-l against SARS-CoV-2 was evaluated using the MTT assay. It was demonstrated that synthetic compounds 4c-e and 4h-j have a potent and selective inhibitory effect on SARS-CoV-2, a strain obtained from Egyptian patients. We utilized density-functional theory (DFT) analyses to deduce the molecular structures and topologies of the more energetic molecules. Molecular docking studies were performed against the SARS-CoV-2 main protease (PDB ID: 6Y84) and the SARS-CoV-2 Nsp9 RNA binding protein (PDB ID: 6W4B) to study the binding mechanism, non-bonding interactions, and binding affinity. Lastly, a hypothetical pharmacophore model was constructed by applying the Molecular Operating Environment (MOE) tool and eleven pharmaceuticals with proven antiviral activity.

Degradation of 2,4-dinitrotoluene from aqueous solutions by three-dimensional electro-Fenton with magnetic activated carbon particle electrodes (GAC/Fe3O4)

Abstract 2,4-Dinitrotoluene (2,4-DNT) is a broadly applied nitroaromatic compound with multiple applications, and its simple production has resulted in its extensive utilization in producing explosives, dyes, and rubber. This substance is hazardous and induces genetic mutations in humans, fish, and microorganisms. Thus, this research was done to assess the effectiveness of the three-dimensional electro-Fenton (3D/EF) process employing magnetic activated carbon particle electrodes (GAC/Fe3O4) in eliminating 2,4-dinitrotoluene from water-based solutions. In this experimental investigation, Fe3O4 nanoparticles were created using the chemical co-precipitation technique. The G/β-PbO2 anode was fabricated by electrochemically depositing PbO2 layers on graphite sheets. G/β-PbO2 and stainless steel were utilized as the anode and cathode, respectively. The structure, particle size, and properties of the GAC/Fe3O4 nanocomposite were analyzed using FESEM, XRD, and EDX. The morphology of the G/β-PbO2 electrode was also examined using SEM. The Taguchi experimental design method was employed to identify the optimal conditions. The outcomes demonstrated that higher reaction time and current density, as well as lower pH and pollutant concentration, resulted in improved 3D/EF efficiency. Accordingly, the optimum values of parmeters were identified to be a concentration of 2,4-DNT = 50 mg/L, pH = 3, electrolysis time = 100 min, and current density = 8 mA/cm2. With these parameters, the degradation efficiency of 2,4-DNT through the examined system was 98.42 %, alongside removal efficiencies of 84.69 % for COD and 79.67 % for TOC. Additionally, the results indicated an increase in the average oxidation state (AOS) (from 1.27 to 1.95) and carbon oxidation state (COS) (from 1.27 to 2.75) in the 3D/EF process, along with a decrease in the COD/TOC ratio (from 1.81 to 1.36), indicating the effectiveness of the 3D/EF system in enhancing the biodegradability of 2,4-DNT. Overall, the combined 3D/EF process with a G/β-PbO2 anode has relatively high efficiency in degrading solutions containing DNT and can be considered a viable treatment option for wastewater containing substances such as 2,4-DNT.

The Role of Surface Oxygen in Eliminating Fluorine Impurities and Relithiation Towards Direct Cathode Recycling

Recycling materials back to supply chain not only mitigates the shortage of critical materials such as the metals of Li, Ni, Co, etc, but also protects global environment. Direct recycling of lithium nickel manganese cobalt oxides (NMC) mainly relies on a relithiation process based on purified spent NMC cathode materials. How to efficiently get rid of chemically bonded surface impurities on spent NMC and obtain a clean surface is critical for relithiation. One of the unavoidable impurities is fluorine, which exists in the form of either carbon fluoride (CFx) or metal fluoride (M-F) and can be eliminated by either thermal treatment or hydrothermal procedure under alkaline environments depending on the state of the F.1,2 Generally the hydrothermal method needs relative high temperature (> 200 °C ) and long reaction time (> 16 hours) due to the slow kinetics. A redox mediator such as H2O2, ethanol or ethylene glycol has been reported to be effective to lower the temperature and pressure for relithiation of recycled NMC111 and NMC622, which was pretreated with N-Methyl-2-pyrrolidone solvent.3 However the mechanism is still not fully understood.This work combines material characterizations and electrochemistry and density functional theory (DFT) calculations to study the role of surface oxygen in eliminating fluorine species on recycled NMC532 cathode material. The recycled NMC532 powders were separated from graphite by froth flotation method and there were significant amount of fluorine impurity species on the surface confirmed by XPS. Initial trial of the addition of small amount of H2O2 additive to LiOH aqueous solution during the hydrothermal process was able to decrease the reaction time significantly to fully eliminate both CFx and M-F species compared to the reaction without H2O2. Further calcination steps with the addition of 5% excessive lithium source using LiOH successfully recovered the recycled NMC532 and the half coin cell using the rejuvenated cathode materials shows a discharge capacity of 154 mAh/g at 0.2 C within 2.7 to 4.2 V voltage range. DFT calculations was conducted on a NMC (012) surface and both lithium hydroxide and sodium hydroxide were selected to understand the role of OH- group and surface oxygen species. The kinetics study was conducted with transition state theory4 and the activation energy barriers were calculated by climbing image nudged elastic band (cNEB) method.5,6 The removal of surface F- takes place with the displacement of F- with OH- (*-(M)F(s) +XOH(s) à XF(s) + *-(M)OH(s), X= Li, Na). F- displacement reactions require more than one basic molecule per F- removal with the formation of either LiF or NaF, which is soluble in water and can be removed by a filtration process. Depending on the surface ‘foreign’ oxygen species, the reaction can either go with a hydroxide pathway or a peroxide pathway, with the latter involving the formation of a peroxide intermediate with a ‘foreign’ oxygen atom leading to much smaller barrier energy compared to that in the hydroxide pathway. On a delithiated surface, the barrier energy for F- removal is predicted to be higher than pristine surfaces as the delithiated surface is less reactive to bind ‘foreign’ oxygen. This is consistent with the experimental results in which the additive of H2O2 can provide ‘foreign’ oxygen atoms and favors peroxide pathway leading to shorter time to remove surface fluorine. Additionally, the reaction with NaOH has a lower barrier than that with LiOH for the removal of fluoride species. Future work will investigate alternative additives as well as fluorine surface-bulk transfer which potentially happen if small amount of fluorine residues exist during calcination step.

FGD-Gypsum Waste to Capture CO2 and to Recycle in Building Materials: Optimal Reaction Yield and Preliminary Mechanical Properties.

The use of waste to capture CO2 has been on the rise, to reduce costs and to improve the environmental footprint. Here, a flue gas desulfurization (FGD) gypsum waste is proposed, which allows us to obtain a CaCO3-based solid, which should be recycled. The CO2 capture stage has primarily been carried out via the direct carbonation method or at high temperature. However, a high energy penalty and/or long reaction times make it unattractive from an industrial perspective. To avoid this, herein an indirect method is proposed, based on first capturing the CO2 with NaOH and later using an aqueous carbonation stage. This allows us to capture CO2 at a near-ambient temperature, improving reaction times and avoiding the energy penalty. The parameters studied were Ca2+/CO32- ratio, L/S ratio and temperature. Each of them has been optimized, with 1.25, 100 mL/g and 25 °C being the optimal values, respectively, reaching an efficiency of 72.52%. Furthermore, the utilization of the produced CaCO3 as a building material has been analyzed. The density, superficial hardness and the compressive strength of a material composed of 10 wt% of CaCO3 and 90 wt% of commercial gypsum, with a water/solid ratio of 0.5, is measured. When the waste is added, the density and the mechanical properties decreased, although the compressive strength and superficial hardness are higher than the requirements for gypsum panels. Thus, this work is promising for the carbonation of FGD-gypsum, which involves its chemical transformation into calcium carbonate through reacting it with the CO2 of flue gasses and recycling the generated wastes in construction materials.

An Identification Method for Anomaly Types of Active Distribution Network Based on Data Mining

With the increasing penetration of distributed generators (DGs) and the growing demand for reliable power sources, it has become imperative to promptly identify anomalies in active distribution networks (ADNs). Additionally, anomaly identification is also crucial to assisting in targeting maintenance to handle failures after the action of relay protections. This study presents a highly accurate and rapidly responsive approach to identifying anomalies in ADNs. The proposed method uses three layers of intricately interconnected modules. In the first module, an iterative clustering layer is devised to process the original data. In the second module, an association rule layer is designed to identify hidden patterns based on the types of anomalies and the post-fault voltage. In the third module, a regression training layer is employed to train accurate identification models. The case study utilizes data samples collected by an IEEE 33-bus system with distributed generations as well as post-fault data from a practical distribution network. The results of comparative tests demonstrate that the proposed data-mining structure achieves reliable performance with high identification accuracy and short reaction times, indicating its ability to be applied to the state awareness system of ADNs.

Engineered anion π complex with non-covalent π interaction system and its catalytic ability on the cyclocondensation reaction of 2-aminobenzimidazole, aryl aldehyde and ethyl acetoacetate

The specific-task engineered anion π complex namely N-sulfopyridin-1-ium monozinc (II) trichloride {[NSPy]ZnCl3} was used as a catalyst for the cyclocondensation reaction of 2-aminobenzimidazole, aryl aldehyde and ethyl acetoacetate with interesting mechanism to give 4H-pyrimido[2,1-b] benzimidazoles in high yields and short reaction times. The designed complex with non-covalent π interaction between [Pyridine–SO3H]Cl and zinc (II) can be acted as multipurpose and efficient catalyst for the preparation of the expected products.

A Mini Review on the Influence of Different Intermediate Mass Transfer Effects on the Chemical Pretreatment of Lignocellulosic Biomass

ABSTRACTChemical pretreatment of lignocellulosic biomass (LCB) in the presence of an alkaline catalyst is one of the major pretreatment processes that recover cellulose, hemicellulose, and lignin at effective process conditions and also for the production of bioethanol. Replacement of conventional catalysts with waste‐derived catalysts in the pretreatment process will be helpful for the development of low‐cost biorefinery. The continuous impact of different mass transfer properties during the chemical pretreatment of LCB will affect the final yield of products at a high reaction time and has been reviewed in the current study. Intraparticle diffusion of an alkaline catalyst into LCB is going to determine the diffusion of the selected catalyst within the porous biomass structure, which helps in the enhancement of the final yield of the product recovery at low‐process conditions. The diffusion of the synthesized catalyst within the selected biomass during the chemical pretreatment process is a rate‐limiting step that influences the final recovery yield of desired products. Enhancement of the biomass pretreatment reaction through the assessment of the diffusivity using the modified Nernst–Einstein relation is also discussed. Determination of different unique mass transfer properties rate of diffusion, diffusivity flux, and mass transfer coefficient are also to be analyzed to advance the reaction rate of the pretreatment process.

Effect of Gender on Reaction Time in Patients Having a Psychiatric Disorder

Background: Reaction time is a measure of how fast an organism can react to a certain stimulus. As such, it is a measure of an individual’s performance and the function of sensory-motor connection. While there are studies evaluating the differences in reaction time with gender and psychiatric illness as independent variables, data are lacking when considering them together. Aims: The aim of the study is to study the gender differences in reaction time in patients suffering from psychiatric illness. Settings and Design: The study involves an observational, longitudinal comparative study in the psychiatric outpatient department (OPD) of a tertiary care facility. Materials and Methods: After institutional ethics approval, 100 patients on psychotropic medications attending psychiatry OPD were included in the study along with at least 100 relatives who were not on psychotropic medications, serving as control. Required data were collected using semi-structured pro forma. The reaction time of patients and the control group was assessed using an application on the mobile phone available online as – the “Human Benchmark test.” Data obtained were entered in the MS Excel sheet and analyzed using the computerized software and a P ≤ 0.05 was considered statistically significant. Results: In the group of patients, the males showed delayed reaction time as compared to females, while in the control group, males performed better than the female population in reaction time tests. The highest reaction time was found to be in the substance use disorder group of patients at all points of testing, followed by that of patients with schizophrenia. Conclusions: Gender did not significantly affect the reaction time in both patient and control groups.

Synthesis of spiro-oxindole-based chemosensor for detection of Hg2+ ions using SBA-Pr-N-IS-Bu-SO3H

Spiro-oxindoles were prepared efficiently via multicomponent reactions (MCRs) for finding the new chemosensors. Also, the use of the efficient nanocatalysts based on SBA-15 in these reactions are so important. Therefore, the functionalization of SBA-15 by different organic compounds are common to produce new efficient nanocatalysts. Herein, SBA-Pr-N-Is-Bu-SO3H as an efficient nanoporous catalyst was applied in the synthesis of (5,6,7,8-tetrahydro-chromene)-4,3′-spirocyclic oxindoles through the three-component reaction of isatin derivatives, malononitrile and dimedone under reflux conditions in high yield and short reaction time. Among all spiro-oxindole derivatives, 2-amino-7,7-dimethyl-5′-nitro-2′,5-dioxo-5,6,7,8-tetrahydro-spiro[chromen-4,3′-indoline]-3-carbonitrile was investigated in fluoresence spectroscopy. According to the obtained results it was observed that in the presence of various cations such as, K+, Ca2+, Na+, Cu2+, Zn2+, Cr3+, Fe3+, Fe2+, Mn2+, Co2+, Al3+, Pb2+, Ag+, Cd2+, Ni2+, Hg2+ and Mg2+, it can selectively detect Hg2+ ion and increase the emission intensity. Its calculated detection limit was 4.6 × 10−7 M, which can be considered a good value. Also, in order to determine the stoichiometric ration for ligand and Hg2+ ion, Job's plot test was performed and the ratio was 1:2.

Nanoporous aluminosilicate mediated synthesis of 2- and 2,2-substituted 2,3-dihydroquinazolin-4(1H)-ones

Nanoporous silicate materials, made by an operationally simple evaporation-induced self-assembly (EISA) approach, efficiently catalyze the formation of 2-substituted 2,3-dihydroquinazolin-4(1H)-ones from aldehydes and dimethyl acetals. This methodology can be extended to encompass the reaction of ketones and ketals to provide facile access to 2,2-disubstituted and spiro dihydroquinazolin-4(1H)-ones in high yields and short reaction times.

Performance Differences of a Touch-Based Serial Reaction Time Task in Healthy Older Participants and Older Participants With Cognitive Impairment on a Tablet: Experimental Study.

Digital neuropsychological tools for diagnosing neurodegenerative diseases in the older population are becoming more relevant and widely adopted because of their diagnostic capabilities. In this context, explicit memory is mainly examined. The assessment of implicit memory occurs to a lesser extent. A common measure for this assessment is the serial reaction time task (SRTT). This study aims to develop and empirically test a digital tablet-based SRTT in older participants with cognitive impairment (CoI) and healthy control (HC) participants. On the basis of the parameters of response accuracy, reaction time, and learning curve, we measure implicit learning and compare the HC and CoI groups. A total of 45 individuals (n=27, 60% HCs and n=18, 40% participants with CoI-diagnosed by an interdisciplinary team) completed a tablet-based SRTT. They were presented with 4 blocks of stimuli in sequence and a fifth block that consisted of stimuli appearing in random order. Statistical and machine learning modeling approaches were used to investigate how healthy individuals and individuals with CoI differed in their task performance and implicit learning. Linear mixed-effects models showed that individuals with CoI had significantly higher error rates (b=-3.64, SE 0.86; z=-4.25; P<.001); higher reaction times (F1,41=22.32; P<.001); and lower implicit learning, measured via the response increase between sequence blocks and the random block (β=-0.34; SE 0.12; t=-2.81; P=.007). Furthermore, machine learning models based on these findings were able to reliably and accurately predict whether an individual was in the HC or CoI group, with an average prediction accuracy of 77.13% (95% CI 74.67%-81.33%). Our results showed that the HC and CoI groups differed substantially in their performance in the SRTT. This highlights the promising potential of implicit learning paradigms in the detection of CoI. The short testing paradigm based on these results is easy to use in clinical practice.

Water-Doped Brønsted Acidic Protic Ionic Liquids for Enhanced Tributyl Citrate Synthesis in a Two-Phase Esterification System.

Tributyl citrate (TBC) plays a crucial role as a plasticizer, enhancing the flexibility of polymers such as polyvinyl chloride. Its biodegradability and non-toxic nature contribute to eco-friendly appeal, making it a preferred additive in diverse industries, including food packaging, medical devices, toys, and consumer goods. Herein, a method for the synthesis of TBC using inexpensive Brønsted acidic protic ionic liquids (ILs) in a two-phase reaction system is presented. The esterification process is carried out with high yield (>99 %), selectivity (up to 98 %) and short reaction time of 2 h. The catalyst in the form of IL shows excellent performance and stability, desirable for industrial applications.

A Simple and Efficient Method for the Nickel‐Catalyzed Synthesis of Azines from Aldehydes and Hydrazines

AbstractAzines are organic molecules with a C=N−N=C functional range of applications. But the conventional azines synthesis process requires a high reaction temperature and long reaction time combined with complex reaction facilities, so the synthesis process needs to be further improved in terms of economic efficiency and process simplification. Here, we demonstrate a structurally well‐defined inorganic ligand Ni compound, (NH4)4[NiMo6O18(OH)6](Ni‐POMs). The catalysts show good activity towards the reaction of carbonyl compounds, and the corresponding products can be obtained in yields up to about 90 %. In this condition, the majority of the aldehydes (aromatic and aliphatic) can be reacted, and the products are obtained in high yields. Density functional theory (DFT) looked into the process by which benzaldehyde and hydrazine hydrate reacted on the surface of Ni‐POMs. It was calculated that the whole reaction goes through two stages and the activation energy of the whole reaction is −6.72 kcal/mol. Thus, from experiment to calculation, a complete structure of the catalytic reaction cycle has been constructed.

Carbon quantum dots-based palladium complex: A versatile nano-catalyst for the green synthesis of pyrazoles

The palladium complex based on the magnetic carbon quantum dots [Fe3O4@CQDS@Si(CH2)3 NH@CC@ATT@Pd (CQDPd = F)] was synthesized by preparation of Fe3O4, its further reactions with carbon quantum dots (CQDs), (3-aminopropyl)triethoxysilane [Si(OEt)3(CH2)3NH2], cyanuric chloride (CC), and 3-amino-1,2,4-triazole-5-thiol (ATT), and complexation of the product with PdCl2. Then, it was characterized by several techniques such as FT-IR, XRD, EDX, SEM, TEM, VSM, and used as a novel catalyst for the green synthesis of diverse pyrazoles from the reaction of aldehydes, ethyl acetoacetate and phenylhydrazine at 70 °C under solvent-free conditions with high yields and short reaction times. Aldehydes bearing the electron-withdrawing groups exhibit the superior reactivity. Remarkably, the F catalyst showed strong recyclability over six consecutive cycles with negligible loss of activity, emphasizing its sustainability and high efficiency in chemical transformations as well as the catalytic potential of the used magnetic carbon quantum dots and their ability to revolutionize green and efficient synthetic methodologies.

Hydrothermal synthesis of zinc molybdates (α-ZnMoO4) nanoparticles and its applications of supercapacitor and photocatalytic performances

Abstract The rational construction and design of nanostructured materials have a significant impact on the fabrication of high-performance electrode materials, which have attracted considerable interest in an effort to enhance the reliability and efficiency of energy storage devices. In this study, the α-ZnMoO4 nanoparticles were successfully prepared by facile hydrothermal method and the influence of various hydrothermal reaction times on structural, morphological, optical and electrochemical properties were studied. XRD analysis illustrated that α-ZnMoO4 nanoparticles exhibited anorthic crystal structure and the average crystallite size was 42 nm. FESEM images changed from a cubic structure to plate-like structures depending on reaction times. HRTEM analysis revealed that prepared sample showed a plate-like structure and the SAED pattern exhibited a polycrystalline nature. The FTIR spectrum confirmed the presence of vibrational molecules in α-ZnMoO4 nanoparticles. The BET and XPS measurements showed the α-ZnMoO4 nanoparticles were mesoporous and had Zn2+ and Mo6+ oxidation states, respectively. From UV–Visible spectra, a better spectral selectivity region was observed at higher reaction times, and the bandgap values were decreased from 2.73 to 2.48 eV. In photocatalytic studies, RhB dye was used as an organic pollutant and achieved a degradation efficiency of 85 % at an optimized reaction time of 24 h. For electrochemical performances, the prepared electrode material showed maximum specific capacitance values of 165 F g−1 and 110 F g−1 for cyclic voltammetry and galvanoststic charge-discharge analysis, respectively.

Kinetic study of the reduction reaction of red mud and CO under fluidization condition

AbstractPyrometallurgical method of iron recovery from red mud (RM) has advantages of simple procedures, high recovery efficiency and significant waste minimization. The fluidization reduction process using CO as reductant addresses the issues of high energy consumption and long reaction time of pyrometallurgical method. In order to optimize the operational conditions of the fluidization reduction process, it is necessary to study the reaction characteristics of RM and CO under fluidization condition. In response to the problems of the current kinetic study including the unsatisfied fluidization condition and possible errors introduced by the estimation method, we carried out improvements in both experiment and data processing. In the experiment aspect, thermo‐gravimetric analyzer (TGA) test rig with large sample capacity and gas flow was established, and approximate fluidization condition was achieved by intensifying diffusion by increasing the gas flow rate and decreasing the sample mass. In the data processing aspect, we developed a program with data cleaning and kinetic function fitting capabilities, and the goodness of fit was evaluated by Akaike information criterion (AIC). The results indicated that within the temperature range of 500–600°C and CO concentrations of 5%–15%, the reaction between RM and CO can be divided into two steps based on the criterion of complete formation of Fe3O4. The first step reaction has a relatively fast reaction rate, conforming to the F1 kinetic function with rate equation given as . The second step reaction displays a more complex pattern and the fitted rate equation is . The obtained results could provide a reliable reference for the operational design of the fluidization reduction of RM.

Green synthesis of 1,3-Thiazolidin-4-ones derivatives by using acid-activated montmorillonite as catalyst

An environmentally friendly, clean, and applicable methodology for synthesizing 1,3-Thiazolidin-4-one derivatives was developed. This method produced the target compounds in high yields and short reaction times by using solvent-free reaction conditions with heterogeneous catalysts, montmorillonite (MT) and acid-activated montmorillonite (acid-MT). MT and acid-MT were investigated in the synthesis using a variety of techniques, including conventional heat, ultrasonic, and microwave irradiation, with the investigation of two types of factors, namely time and temperature. X-ray diffraction, N2 adsorption–desorption, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy were used to characterize the MT and acid-MT catalysts. FTIR, 1H NMR, 13C NMR, and mass spectra were used to characterize each product. The ring-cyclization step, with its short time and high yield percentage, is the most important factor for the strength of the prepared catalyst, acid-MT. Additionally, the acid-MT catalyst was easily recoverable and can be reused up to five times without suffering a substantial reduction in catalytic activity.