Reflux Condensation Research Articles

SYNTHESIS AND CHARACTERIZATION OF SALICYLALDEHYDE AND 2,4-DINITROPHENYL HYDRAZINE SCHIFF BASE WITH ITS COBALT (II) AND MANGANESE (II) COMPLEXES

The synthesis of Schiff base derived from salicylaldehyde and 2,4-dinitrophenyl hydrazine and its metal complexes were undertaken. This synthesis was achieved via the reflux condensation of salicylaldehyde and 2,4-dinitrophenyl hydrazine. Two metal complexes were prepared by coordinating the as-synthesized ligand with Cobalt (II) and Manganese (II) ions. The structures of the prepared ligand and the complexes were confirmed from the Fourier transformed infrared analysis. A laboratory tests were employed to study the melting and decomposition temperatures, Solubility, conductivity and magnetic susceptibility. The ligand obtained was a pale orange in colour with a percentage yield of 67% and melting point of 220ºC, The Cobalt(II) complex was found to be Orange in colour with 89% percentage yield and 250ºC decomposition temperature and the Manganese(II) complex was found to be a deep orange colour with 81% percentage yield and 246ºC decomposition temperature, The ligand and the complexes were found to be insoluble in water and slightly soluble in some common organic solvents, All the complexes are found to be paramagnetic in nature.

Efficient triethylamine sensing achieved by in-situ Zn2+ doping regulated Mo-MOFs derived MoO3/ZnMoO4 heterostructures

Triethylamine (TEA) poses severe safety hazards to industrial production and human health. To accurately detect TEA concentrations and rapidly warn of leakage, a simple reflux condensation method was deployed to successfully incorporate Zn2+ in situ into Mo-MOFs precursor in a green, safe, and time-efficient synthesis condition. Subsequently, through calcination, MoO3/ZnMoO4-X (MMZ-X) were prepared, which exhibited an increased number of defects and enriched porosity, facilitating the access and interaction of TEA with adsorption sites. Simultaneously, rationally built in situ MoO3/ZnMoO4 heterostructures accelerated carrier migration and induced a drastic resistive change. MMZ-2 demonstrated outstanding TEA sensing performance, exhibiting extremely high sensitivity (R = 572.3, 100 ppm), along with superior selectivity, repeatability and stability, rapid response and recovery times, and a low detection limit. Moreover, the key intrinsic parameters of the heterostructure on the atomic scale were determined by density functional theory (DFT) calculations, providing a detailed elucidation of the sensing enhancement mechanism of the MoO3/ZnMoO4 heterostructure. The simple and efficient synthesis method and the related mechanistic analysis pave a new path for designing high-performance TEA gas sensors with practical applications.

Utilization of copper chromite-reduced graphene oxide nanocomposite for the wastewater remediation and effective supercapacitive performance

This article has detailed the growth of virgin copper chromite nanoparticles (CuCr2O4 NPs) and reduced graphene oxide sheet (rGO)-based CuCr2O4 nanocomposite through the process of reflux condensation method and calcination process. When exposed to visible light, these two synthesized nanomaterials exhibit enhanced photocatalytic activity which helps in the degradation of organic dyes such as methylene blue. Numerous characterization methods, including FTIR, UV–visible analysis, and XRD, verify the creation of these nanomaterials. The CuCr2O4-rGO nanocomposite's semiconductor nature is confirmed by the band gap analysis using Tauc's formula. The CuCr2O4 NPs grown on the rGO surface have a dimension of 6 nm, according to the TEM study and particle distribution graph. To find the reason for the enhanced photo-activity, we have proposed a photocatalytic mechanism which is supported by photoluminescence result. Recyclability in five more cycles is used to measure the stability of the nanocomposite, and it is found that photocatalytic efficiency does not significantly decline up to five cycles. When exploring the CuCr2O4-rGO nanocomposite as a material for supercapacitor electrodes, it showcased a remarkable specific capacity of 681.43 F/g at 0.5 A g−1. Moreover, the CuCr2O4-rGO nanocomposite electrode displayed a long-term life cycle, retaining 93.8 % of its initial capacity after 1200 cycles, paired with a commendable Coulombic efficiency of 95.31 % and outstanding power and energy density of 1504 W/kg and 23.66 Wh/kg respectively.

Continuous alkylation of 1,3,5-trihydroxy-2,4,6-trinitrobenzene in microreactor: Process intensification and reaction kinetics

1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is an essential insensitive energetic material. The alkylation of 1,3,5-trihydroxy-2,4,6-trinitrobenzene (Trinitrophloroglucinol, TNPG), which yields 1,3,5-triethoxy-2,4,6-trinitrobenzene (TETNB), is a pivotal step for the synthesis of TATB. The conventional synthetic process has suffered from long reaction time (∼165 min), intricate procedures, and intensive evaporation of a large number of volatile by-products, which increases the risk of spill and eruption of the reaction system, and necessitates in situ continuous gas–liquid separation. A new process for continuous alkylation in microreactors was proposed in this study. Firstly, a parametric investigation in the batch reactor was performed to explore the effects of various process parameters on the yields, resulting in the optimal experimental conditions, i.e., no reflux condensation, triethyl orthoformate (TEOF) as alkylation reagent, molar ratio of 12, reaction temperature of 120 °C and reaction time of 40 min. Subsequent continuous synthesis in microreactors was conducted, which realized the convenient process operation and no need of gas–liquid separation, leading to substantial improvement in the reaction efficiency and safety. Remarkably, within a packed microreactor, under the reaction temperature of 130 °C and residence time of 3 min, 99.24 % in the yield of TETNB was achieved. Comparing with conventional batch reactors, the required reaction time was reduced to approximately 1/50. Taking the advantages of precise control of temperature and reaction time in the microreactors, the kinetics of alkylation reaction were determined. This innovative approach of continuous synthesis can provide an efficient and alternative route for the synthesis of TATB, as well as other energetic materials and similar processes.

Synthesis of novel bi-Zwitterion Schiff base derivate from 4‑hydroxy-2H-pyran-2-one: DFT/HSA-interactions, thermal, physicochemical, TD-DFT and optical activity

A novel tetradentate bi-Zwitterion Schiff base (SB): 3,3′-((1E,1′E)((oxybis(4,1-phenylene))-bis-(azanylylidene))-bis(ethan-1-yl-1-ylidene))bis(4‑hydroxy-2H-pyran-2-one) was synthesized, via reflux condensation of 3-acetyl-4‑hydroxy-6-methyl-2H-pyran-2-one with 4,4′-oxydianiline in methanol. The SB ligand was characterized using various physicochemical techniques, including 1HNMR , elemental analysis (CHN-EA), XRD, MS, UV–vis, and FT-IR. The XRD analysis confirmed the presence of a bi-zwitterionic salt form, characterized by intra-H-bond interactions between [N+—H…−O] groups. Hirschfield surface analysis (HSA) and MEP/MAC/NPA were conducted to gain insight into the intra/intermolecular hydrogen bond interactions of the molecule. The completion of the SB dehydration reaction was UV–vis., tracked by studying the behavior of the reactants before and after mixing. Additionally, the absorbance/transmittance, TD-DFT, and optical properties of the SB were evaluated. Finally, the TG/DTG analysis was used to determine the thermal stability of the desired SB ligand.

Polyacrylate modified alkyd hybrid latex with high anti-corrosion performance synthesized via solvent-free and emulsifier-free method

Polyacrylate modified alkyd hybrid emulsion (SPA-WAR) was prepared by solvent-free and emulsifier-free method to solve the problem of contamination of organic solvent in the preparation of alkyd resin. The originality of this paper lies in the special introduction of acrylic monomers. On the one hand, as a solvent, acrylic monomers play the role of reflux and dilution to reduce viscosity and drainage. On the other hand, as reactive monomers, acrylate monomers were grafted to alkyd resin to form macromolecular polymer. Due to the presence of hydrophilic groups in the polyacrylate chain, SPA-WAR can be obtained without the use of surfactants. This method does not need to add additional solvents and emulsifiers, and has the advantages of green environmental protection. Since the acrylate monomer plays the role of reflux condensation, the yield will also be greatly improved. In addition, compared with water-based alkyd resin (WAR) and acrylate-modified alkyd resin prepared by solvent method (PA-WAR), the particle size of SPA-WAR latex is smaller and the surface of SPA-WAR film is smoother. SPA-WAR coating has excellent physical properties and anti-corrosion properties. After 180 h salt spray treatment, SPA-WAR-latex coated tinplate has no obvious corrosion and diffusion.

Effect of annealing environment on the electrochemical performance of biosynthesized V2O5@C thin films

In the present work, the V2O5 thin films were prepared on flexible stainless steel mesh (FSSM) substrate using Bengal gram bean extract (BGBE) as a medium by reflux condensation method for its use as an electrode for supercapacitor application. The bio-molecules present in BGBE were in-situ converted into carbonaceous material after the annealing process. A systematic study of the influence of the annealing environment was investigated by heating the as-prepared V2O5 thin films in two different annealing atmospheres viz nitrogen and air. The annealing of the as-prepared V2O5 thin films under N2 atmosphere (V2O5-N) produces more carbonaceous material when compared to V2O5 thin films annealed in air atmosphere (V2O5-A). Interestingly, annealing in air atmosphere completely oxidizes the biomass, while annealing in nitrogen leaves traces of carbonaceous matrix in the thin film. This improves the conductivity and electrical properties of the material and its advantage is taken in fabricating supercapacitor devices. The obtained V2O5-N and V2O5-A thin films were characterized using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Raman, and X-ray Photoelectron Microscopy (XPS). Moreover, the electrochemical performance of V2O5-N and V2O5-A was investigated. The V2O5-N electrode exhibited a specific capacitance (Csp) of 633.3 F g−1 with an energy density (ED) of 87.9 wh kg−1 at 2 mA cm−2 current density and good cycles stability with capacitive retention of 86.2 % over the 10,000 continuous GCD cycles which is higher than the V2O5-A. A flexible symmetric solid state (SSC) device was assembled using V2O5-N electrodes with PVA-LiClO4 gel electrolyte. The device exhibited a Csp of 82.6 F g−1 with an ED of 22.4 wh kg−1 at 1 mA cm−2 current density. In summary, the V2O5-N demonstrated significantly improved electrochemical performance than the V2O5-A electrode and is supported with the appropriate data.

Economic and binder-free synthesis of NiCo2O4 nanosheets on a Flexible stainless steel mesh as a bifunctional electrode for water splitting

Water as a green source of hydrogen has attracted the attention of researchers considering its potential applications in the energy sector. Thus, developing efficient bifunctional electrocatalysts for water splitting is a potential challenge perceived by researchers exploring the development of sustainable energy technologies. With this motive, the present study focuses on the preparation of the highly active, economic, binder-free, and bifunctional NiCo2O4 nanosheets@ Flexible Stainless Steel Mesh substrate (NCO@FSSM) electrocatalyst via reflux condensation method for the bulk O2 and H2 production. The influence of reflux condensation temperatures (100, 120, 140 °C) on the morphology and electrocatalytic activity is investigated. Electrocatalytic properties for NCO@FSSM synthesized at 120 °C were noted exhibiting smaller overpotentials for oxygen evolution reaction (OER, 310 mV) and hydrogen evolution reaction (HER, 79 mV) at 10 mA cm−2, which were lowest among the previously reported Ni, and Co-based electrodes. Additionally, the scale-up experiments with NCO-120@FSSM film (8 cm X 8 cm) as an anode and FSSM as a cathode and vice-versa, in a specially designed scale-up electrochemical cell revealed steady electrocatalytic performance. The real-time water splitting was studied for 25 h and was noted to produce 7.4 L of (O2) and 11.5 L of hydrogen (H2).

PWR natural circulation at a small break LOCA

In this paper, a one-dimensional quasi-steady model has been developed to analyse the potential impacts of reduced primary coolant inventory on natural circulation. This model focuses on the development of expressions for the coolant inventory, temperature distributions, and mass flow rate. The model encompasses a range of fluid flow scenarios, including single-phase, combined single-and-two-phase, and two-phase natural circulation, as well as the phenomenon of reflux condensation. The model is also utilized to examine the impact of reactor core power on natural circulation parameters. Comparisons with experimental findings and earlier research are made, highlighting a satisfactory level of agreement with the analytical findings. Based on the findings of this study, it has been observed that within the range of primary coolant inventory of 100–60% and core decay power of 1.5–5% of full power, natural circulation in a PWR type system has the potential to serve as an effective mechanism for transferring core decay heat to the secondary loop. The flow rates of natural circulation in pressurized water reactors (PWRs) are observed to have a significant dependence onthe amount ofliquid inventory, whereas their relationship with power level is comparatively less pronounced. The flow rate of a pressurized water reactor (PWR) system tends to exhibit its highest value within a specific range of inventory, typically falling between 60% and 80%. The transition between the different modes of natural circulation is observed to exhibit a smooth transition, with varying system inventories.

Synthesis of Tio2 photocatalyst with tunable optical properties and exposed facet for textile wastewater treatment

TiO2 semiconductor plays a paramount important as an active photocatalyst mainly due to its photo-induced electron transfer properties. The metastable anatase in particular are widely accepted to have the most photoactive activity in catalytic application as opposed to rutile TiO2. This is majorly due to the significantly lower recombination rate of electron pair possesses by anatase TiO2. Unfortunately, high recombination rate in anatase TiO2 hinders its application as a functional photocatalyst. Therefore, it is crucial to further enhance the photocatalytic activity of anatase TiO2, by modifying its optical properties, morphological properties, and crystal facet. The study aims to provide a benign synthesis method for TiO2 with a co-exposed {001}/{100} anatase TiO2 facet. The synthesis was conducted via one-pot reflux condensation method. A concise evaluation upon the effect of different synthesis heating duration, temperature and doping materials towards the crystal phase, morphology, and photocatalytic performance of TiO2 were conducted. Anatase TiO2 with high percentage of the high-energy {001} facet have the ability to boost the adsorption and photocatalytic performance as opposed to anatase TiO2 dominated with a thermodynamically stable {101} facet. The incorporation of non-metal dopant (HF) acts as surface modifier which leads to the enhancement of {001} facet percentage. This study further evaluates the functionalities of HCl in paving way towards the formation of mid-gap state, hence improving Anatase TiO2 optical properties. The reduction of band gap of the anatase TiO2 can clearly be identified from the shifts in the adsorption band towards higher wavelength. From the findings, it was found that the synergistic effect upon co-doping anatase TiO2 with the two non-metal dopants plays an important role in altering the ratio of exposed facet hence leading towards improving the photocatalytic efficiency of the nanomaterial. To evaluate the photocatalytic performance of the synthesized TiO2, Remazol Brilliant Blue (0.01 g/L) was chosen as the target pollutant. The enhanced photodegradation of co-doped F/Cl-TiO2 was evaluated and it was found that 87.21% and 43.21% of Remazol Brilliant Blue had successfully been degraded within 120 min with irradiation of broad spectrum and blue light (475 nm) respectively. This is mainly attributed to the co-exposed {001}/{100} anatase TiO2 facet presence in the F/Cl-TiO2 sample.

Construction of Well-Defined Two-Dimensional Architectures of Trimetallic Metal-Organic Frameworks for High-Performance Symmetric Supercapacitors.

The high surface-to-volume ratio and extraordinarily large-surface area of two-dimensional (2D) metal-organic framework (MOF) architectures have drawn particular interest for use in supercapacitors. To achieve an excellent electrode material for supercapacitors, well-defined 2D nanostructures of novel trimetallic MOFs were developed for supercapacitor applications. Multivariate MOFs (terephthalate and trimesate MOF) with distinctive nanobrick and nanoplate-like structures were successfully synthesized using a straightforward one-step reflux condensation method by combining Ni, Co, and Zn metal species in equimolar ratios with two different ligands. Furthermore, the effects of the tricarboxylic and dicarboxylic ligands on cyclic voltammetry, charge-discharge cycling, and electrochemical impedance spectroscopy were studied. The derived terephthalate and trimesate MOFs are supported with stainless-steel mesh and provide a suitable electrolyte environment for rapid faradaic reactions with an elevated specific capacity, excellent rate capability, and exceptional cycling stability. It shows a specific capacitance of 582.8 F g-1, a good energy density of 40.47 W h kg-1, and a power density of 687.5 W kg-1 at 5 mA cm-2 with an excellent cyclic stability of 92.44% for 3000 charge-discharge cycles. A symmetric BDC-MOF//BDC-MOF supercapacitor device shows a specific capacitance of 95.22 F g-1 with low capacitance decay, high energy, and power densities which is used for electronic applications. These brand-new trimetallic MOFs display outstanding electrochemical performance and provide a novel strategy for systematically developing high-efficiency energy storage systems.

Structural and biological evaluation of novel vanadium/Yttrium co-doped hydroxyapatite for bone tissue engineering applications

Hydroxyapatite (HA) is widely used in various medical fields due to its exceptional bioactivity, bio-affinity, and biocompatibility. However, the potential of biomaterials co-doped with metal ions for specific biomedical applications remains underexplored. In this study, we modified the HA structure by introducing vanadium (V) and yttrium (Y) to enhance its physicochemical and biological properties. V-Y co-doped HA (V-Y:HA) samples were prepared by the wet precipitation method using a reflux condensation setup with three different concentrations (0.005 M, 0.01 M, and 0.02 M) of V and Y. The addition of V and Y significantly influenced the biochemical properties and crystal structure of HA. X-ray diffraction (XRD) analysis revealed a modified crystal structure and the presence of the β-tricalcium phosphate (β -TCP) phase in the sample with a higher V concentration. V and Y incorporation resulted in smaller crystallite sizes and noticeable changes in lattice parameters. Scanning electron microscopy (SEM) images displayed sphere-like morphology with extensive aggregation. Fourier-transform infrared spectroscopy (FT-IR) and Raman analysis confirmed the presence of functional groups and phosphate vibrational modes in V-Y:HA samples. X-ray photoelectron spectroscopy (XPS) revealed the ionic and oxide forms of vanadium and the electronic states of yttrium. The as-prepared samples exhibited excellent mechanical strength, reduced porosity, and improved hemocompatibility compared to pure HA. The V-Y:HA sample with a higher V concentration demonstrated enhanced antibacterial activity against P. aeruginosa and S. aureus. In-vitro bioactivity assessment after 21 days revealed enhanced apatite formation on the surface of HA and V-Y:HA materials. These findings suggest that the novel V-Y:HA nanomaterials have great potential as biomaterials for bone tissue engineering and related applications.

Molecular Insights into the In Vivo Analgesic and Anti-Inflammatory Activity of Indomethacin Analogues.

The primary objective of this research was to identify and explore the most potent and efficacious cyclooxygenase inhibitors, utilizing indole acetic acid drugs as a lead molecule. To achieve this objective, various derivatives (2a-2c and 2e-2g) of the selected lead molecule, indomethacin, were synthesized using a reflux condensation process, targeting the hydroxyl group. The synthesized analogues were subjected to different spectroscopic procedures to determine their structure and confirm their analogues. These derivatives were further screened for acute toxicity and anti-nociceptive and anti-inflammatory activity using established protocols. Docking analysis was performed to evaluate the possible protein-ligand interaction. The test compounds were found to be safe at doses of 50, 75, 100, and 200 mg/kg, i.p. The pharmacological screening revealed that test compounds 2a-2f had a superior peripheral analgesic effect at a dose of 10 mg/kg, in comparison to the parent drug indomethacin, while compound 2g exhibited slightly lower activity at the same dose. The hot plate results showed lower central analgesic activity of the test compounds compared to the standard Tramal, but it was still significant. Anti-inflammatory results were significant, comparable to Diclofenac sodium and indomethacin, except for compounds 2b, 2c, and 2e at a dose of 10 mg/kg body weight. Molecular docking analysis demonstrated that the derived compounds had augmented negative binding energies (-149.39, -146.72, -160.85, -159.34, -140.03, and -150.91 KJ/mol) compared to the parent drugs (-141.07), which supported the research's theme of producing stronger derivatives of standard drugs with significant anti-nociceptive and anti-inflammatory potential. The derived compounds exhibited significant analgesic and anti-inflammatory activities and, therefore, have the potential to be studied further as new drug candidates for pain and inflammation.

High-performance solid-state asymmetric Supercapacitor based on α-Fe2O3/r-GO/GCN composite electrode material for energy storage application

Herein, a 3D/2D/2D of α-Fe2O3/r-GO/GCN composites were synthesized by combined reflux condensation and sonochemical-assisted wet-impregnation techniques. The physicochemical properties of the prepared materials were inspected by various analytical techniques. Morphology analysis techniques of different electron microscopes were employed to confirm the rhombohedral (3D) and two-dimensional (2D) sheets' morphology. The electrochemical behaviour of the as-synthesised electrode materials was assessed for use in a redox electrolyte-based energy storage system. Electrochemical measurements in a 6M KOH solution revealed that the electrode exhibited good supercapacitive behaviour. The 3D/2D/2D -α-Fe2O3/r-GO/GCN composite had a higher capacitance rate of roughly 810 F g−1 than α-Fe2O3 nanoparticles at 1Ag−1. From cyclic stability, ternary composite has good cyclic retention (98.9%) after 10,000 cycles at 10 Ag−1. The surface characteristics of metal oxide nanostructures and the efficient conductive networks of r-GO and GCN sheets are primarily responsible for the ternary α-Fe2O3/r-GO/GCN composite's superior electrochemical performance. Asymmetric supercapacitor (ASC) devices were constructed using 3D/2D/2D anodic material and activated carbon as a cathode material with a power density of 929 Wkg−1, energy density of 40 WhKg−1, and 92 % of capacity retention.

Effect of Small Change in Reaction Conditions on the Size of Monoclinic BiVO4 Nanoparticles and their Photocatalytic Abilities

AbstractBiVO4 is an effective material and highly used in different applications. Here, we have synthesized BiVO4 using bismuth nitrate pentahydrate and ammonium metavanadate by simple reflux condensation method without addition of any surfactant. To check the effect on the structure and activity of BiVO4 different ratios of bismuth nitrate pentahydrate to ammonium metavanadate e. g. 1 : 1, 1 : 2 and 2 : 1 were used. Obtained BiVO4 nanomaterial was successfully analysed using various analytical techniques such X‐ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Field emission scanning electron microscopy (FE‐SEM) and X‐ray photoelectron spectroscopy (XPS). The nanoparticles were shown spherical morphology, high porosity and monoclinic scheelite (m) crystalline phase. It was observed that BiVO4 nanoparticles prepared using 1 : 1 ratio have very small size as compared to those prepared using other ratios. Further, the photocatalytic activity of the BiVO4 nanoparticles was assessed by photodegradation of crystal violet dye (CV) under visible light irradiation and found that the particles prepared with 1 : 1 ratio were showing high efficiency of degradation. In addition, prepared nanoparticles have shown good antibacterial properties.

Structural and biological properties of novel Vanadium and Strontium co-doped HAp for tissue engineering applications

The development of novel bioactive materials with improved physical and biological properties is crucial for advancing tissue engineering applications. In this study, we synthesized a Vanadium and Strontium co-doped hydroxyapatite (V–Sr:HAp) nanoparticle intending to enhance the performance of pure HAp. The V–Sr:HAp nanoparticles were synthesized using a microwave-assisted reflux condensation method, and their structural and chemical characteristics were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The morphology and elemental composition of the nanoparticles were examined through scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The XRD analysis confirmed the presence of characteristic peaks of HAp in each sample. SEM images revealed well-connected and highly agglomerated small sphere-like morphology in both pure HAp and V–Sr:HAp nanoparticles. The Vickers hardness test demonstrated the improved mechanical strength in V–Sr:HAp compared to pure HAp. Antibacterial efficacy was evaluated using an agar diffusion test, which showed enhanced antibacterial activity in the co-doped HAp samples against S. aureus and P. aeruginosa. Moreover, the Ca–P deposition rate on the surface of the co-doped HAp samples during biomineralization was higher. Hemolysis assay results have indicated compatibility of both pure HAp and V–Sr:HAp with human blood (<5% lysis). The results of cell viability tests demonstrate that the V and Sr co-doped HAp samples do not exhibit any cytotoxic effects and instead promote cell proliferation. Overall, the incorporation of V and Sr metal ions into HAp presents a promising bio-functional tool for tissue engineering applications, offering improved mechanical and antibacterial properties.

Integral-Effect Test for Loss of Residual Heat Removal System During Mid-Loop Operation in ATLAS Facility

A test called B4.2 in the OECD-ATLAS2 project was performed to simulate loss of the residual heat removal system (RHRS) during mid-loop operation (MLO) using a thermal-hydraulic (T-H) integral-effect test facility: the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS). The main purpose of this test was to investigate a T-H transient in the reactor coolant system (RCS) during loss of the RHRS and to evaluate the effectiveness of reflux condensation and the capability of a safety injection tank (SIT) on shutdown coolability. The initial and boundary conditions for the B4.2 test were appropriately determined according to a state of MLO corresponding to 65 h after reactor trip in the Advanced Power Reactor 1400 MW(electric) (APR1400). During the loss of RHRS accident transient simulation, major T-H parameters such as system pressures, temperatures, and collapsed water levels in the RCS were measured, and unique T-H phenomena such as reflux/cocurrent condensations, off-take, countercurrent flow, and countercurrent flow limitation were investigated. In this paper, the overall T-H behavior in the RCS during a simulated loss of the RHRS with SITs is highlighted to provide a better understanding of T-H phenomena regarding coolability with reflux condensation.

Enhancing photodegradation of Methyl Orange by coupling piezo-phototronic effect and localized surface plasmon resonance

Piezo-potential promoted photocatalysis enables a scalable and high-efficiency dye decomposition by conjugating the photoexcitation and mechanical stimulus. However, its catalytic efficiency is significantly restricted by the limited quantum yield and piezoelectric activity of catalysts. Herein, a heterogeneous CdS-Au composite photocatalyst was synthesized via a facile water bath heating and reflux condensation method for organic pollutants degradation. The synergism between piezo-phototronic effect and localized surface plasmon resonance facilitates photon-generated carrier separation and internal quantum efficiency. The loading of Au nanoparticles remarkably modulates the morphologies, surface defect, effective optronics utilization and photocatalytic activities of CdS nanospheres. A 2.3 folds enhancement in the photodegradation of Methyl Orange (MO) was observed with the optimal 4 mol% Au loading. Furthermore, the impact of frequency and intensity of ultrasonication on the electrochemical impedance and photocatalytic activity was systematically investigated. This work offers a promising approach for harnessing noise or vibration for environmental remediation and opens up a new route for designing and developing high-performance piezo-photocatalyst.

Molybdenum Carbide/Cobalt Composite Nanorods via a “MOFs plus MOFs” Strategy for High-Efficiency Microwave Absorption

Herein, we report the synthesis of one-dimensional (1D) molybdenum carbide/cobalt nanorods that consist of multiple components including Mo2C, Co, and C (Mo2C/Co/C) based on a “MOFs plus MOFs” strategy. The 1D Mo-metal–organic frameworks (MOFs) were first prepared through reflux condensation. Then, a zeolitic-imidazolate framework (ZIF-67) was used as the Co source to decorate 1D Mo-MOFs to form the Mo-MOFs/ZIF-67 precursor. Finally, 1D Mo2C/Co/C ternary composite nanorods were obtained through pyrolysis of Mo-MOFs/ZIF-67 under an Ar atmosphere. The combination of multiple components including dielectric Mo2C, C, and magnetic Co could not only optimize the impedance matching but also provide multiple channels to attenuate the electromagnetic (EM) waves including conductive loss, dielectric polarization, and magnetic resonance. Besides, the interface polarization formed by abundant heterointerfaces between Mo2C and Co/C was confirmed using a high-frequency structure simulator. The adding amount of Mo-MOFs and pyrolysis temperature were found to have a significant influence on the impedance matching and microwave absorption. Consequently, the optimized Mo2C/Co/C nanorods displayed the strongest reflection loss (RL) of −54.6 dB at 16.2 GHz corresponding to a thickness of 1.77 mm. The SRLmt (RL/matching thickness) was calculated to be 30.9, exceeding those of reported MOF derivates. What is more, the Mo2C/Co/C nanorods exhibited broad and tunable bandwidth covering from the whole X band (8.0–12.08 GHz) to the Ku band (12.56–18.0 GHz) by adjusting the amount of Mo-MOFs and pyrolysis temperature, revealing great potential for fields of microwave absorption.

ANTI-CORROSIVE POTENTIALS OF NAPHTHO-QUINONE/NAPHTHA-ALDEHYDE SCHIFF BASES FOR MILD STEEL IN HCL MEDIUM: SYNTHESIS, CHARACTERIZATION AND DFT STUDIES

The corrosion inhibition of four ligands; L1, L2, L3 and L4 synthesized through reflux condensation, and characterized via spectroscopic methods were examined using weight loss measurements and Density Functional Theory(DFT). Factors like ligand’s chemical structure, immersion time, concentration, and temperature which affect efficiency of corrosion inhibition were evaluated. The experimental results revealed declined weight losses from 0.02-0.004g, 0.06-0.00625g and 0.11450- 0.06938g at 303K, 333K, and 363K temperature for concentration increase from 100-500ppm. The increase in weight loss arose from temperature (303-363K) increase. Obtained data denotes declined corrosion rate in the presence of the inhibitors in the acid solutions but decreased as the inhibition concentration increased at each temperature. The highest inhibition efficiency (%ᶯwL) for the ligands at 303K, 333K and 363K temperatures and 500 ppm concentration were observed as 89.39% (L3), 88.36% (L2) and 55.00% (L2) respectively. The exceptional inhibition proficiency of the ligands could be due to the availability of heteroatoms and aromatic rings with π-electrons within their structures. The increase in %ᶯwL for 5 hours immersion was in the order L2&lt;L4&lt;L1&lt;L3, L1&lt;L3&lt;L4&lt;L2 and L3&lt;L1&lt;L4&lt;L2 at 303K, 333K, and 363K temperature respectively with L3 having the highest %ᶯwL at 89.39% at 303K. The desorption process of the ligands upon the mild steel surface (mss) followed Langmuir adsorption isotherm. The ∆Gads values acquired were amid -18.1709 to -35.6765KJ mol-1 suggestive of adsorption of the studied inhibitors on mss been physisorption. Chemical calculations and molecular descriptors of dipole moment(μ), energy gap, EHOMO, and ELUMO were acquired via B3LYP level with 6-31G (d, p) basis, while global reactivity descriptors; global softness(S), global hardness(η), electrophilicity index(ω) were derive and analyze using Koopman’s theorem. The ligands were found to be in good agreement with both experimental and theoretical results. The L3 ligand had the highest EHOMO value of - 8.4696567 denoting greater inhibition potency and conforming to the result obtained from corrosion %ᶯwL. The structural assemblages of the ligands were confirmed using spectroscopic and analytical methods.