High Reactive Nature Research Articles

Poly-(aminoethyl piperazine) membranes with ultra-thin selective layers prepared via a rate-retarded interfacial polymerization method

New monomers have been exploring to fabricate interfacial polymerized thin film composite membranes for decades. N-aminoethyl piperazine (AEP), an aliphatic amine with a heterocyclic structure, was used in this work as an amine monomer to synthesize nanofiltration membranes. Due to the high reactivity nature of AEP, a rate-retarded interfacial polymerization method was applied, which was realized by applying ultra-low AEP concentration (0.07 wt%), low reaction temperature (4 °C monomer solutions), and ice-water quench. The resulting AEP membrane had much better performance (3–4 times permeance and closed rejections) compared with the membranes prepared by the hot water post-treatment and the oven heat treatment. At lower monomer concentrations, an NF membrane with a selective layer thickness of only around 20 nm was prepared by the rate-retarded interfacial polymerization method. The membranes had a negatively charged surface with "willow leaf" like morphology. The MWCO was around 200 g mol−1, and the water permeance was up to 22.8 L m−2 h−1 bar−1, which is comparable with the commercial polyamide membrane NF270. Therefore, AEP is a very competitive alternative monomer for NF membrane synthesis.

Numerical Analysis of Dual Fuel Combustion in a Medium Speed Marine Engine Supplied with Methane/Hydrogen Blends

Compression ignition engines will still be predominant in the naval sector: their high efficiency, high torque, and heavy weight perfectly suit the demands and architecture of ships. Nevertheless, recent emission legislations impose limitations to the pollutant emissions levels in this sector as well. In addition to post-treatment systems, it is necessary to reduce some pollutant species, and, therefore, the study of combustion strategies and new fuels can represent valid paths for limiting environmental harmful emissions such as CO2. The use of methane in dual fuel mode has already been implemented on existent vessels, but the progressive decarbonization will lead to the utilization of carbon-neutral or carbon-free fuels such as, in the last case, hydrogen. Thanks to its high reactivity nature, it can be helpful in the reduction of exhaust CH4. On the contrary, together with the high temperatures achieved by its oxidation, hydrogen could cause uncontrolled ignition of the premixed charge and high emissions of NOx. As a matter of fact, a source of ignition is still necessary to have better control on the whole combustion development. To this end, an optimal and specific injection strategy can help to overcome all the before-mentioned issues. In this study, three-dimensional numerical simulations have been performed with the ANSYS Forte® software (version 19.2) in an 8.8 L dual fuel engine cylinder supplied with methane, hydrogen, or hydrogen–methane blends with reference to experimental tests from the literature. A new kinetic mechanism has been used for the description of diesel fuel surrogate oxidation with a set of reactions specifically addressed for the low temperatures together with the GRIMECH 3.0 for CH4 and H2. This kinetics scheme allowed for the adequate reproduction of the ignition timing for the various mixtures used. Preliminary calculations with a one-dimensional commercial code were performed to retrieve the initial conditions of CFD calculations in the cylinder. The used approach demonstrated to be quite a reliable tool to predict the performance of a marine engine working under dual fuel mode with hydrogen-based blends at medium load. As a result, the system modelling shows that using hydrogen as fuel in the engine can achieve the same performance as diesel/natural gas, but when hydrogen totally replaces methane, CO2 is decreased up to 54% at the expense of the increase of about 76% of NOx emissions.

Phosphate Starvation Responses in Plants and Microbe Mediated Phosphorus Recycling in Soil: A Review

Phosphorus (P) is an essential macronutrient, crucial for intensification of agricultural production. Although P is a vital nutrient for all life forms but in natural ecosystem it is least available owing to its high reactive nature. Plants have developed diverse adaptive strategies to improve Pi acquisition and utilization under inadequate condition. They undergo numerous modifications at morphological, physiological, and biochemical level to maintain P homeostasis under deplete conditions of P. In last decades, notable development has been made in utilizing microbes for regulating P supply in soil solution. In this review, we focused on the understanding of P uptake from soil, mobilization within plants, phosphate starvation responses and efficacy of microorganisms in facilitating external P to plants. Moreover, other metabolism in microorganism viz. phosphate accumulation is an important trait of microbes to maintain labile P in soil solution. Application of phosphate accumulating microbes is well known in enhanced biological phosphorus removal (EBPR) system and heavy metal remediation. This review also discussed the phosphate accumulation mechanism in microbes and their importance in regulating P supply in soil. Current knowledge and further exploration of mechanism involved by P accumulating microbes may offer better insight of the regulatory events controlling P homeostasis. It will be beneficial for developing more efficient sustainable technologies to augment P use efficiency in soil for better plant growth promotion and nutrient starvation alleviation.

Removal of Methylene blue Dye from water through Photocatalytic Activity Using Polymer-Metal Oxide Nanocomposites – a Comparative Study

The dye-containing effluent from the textile, paper, and food sectors is brightly coloured and has extremely negative impacts on living creatures. Dye degradation into a non-toxic state is useful for reducing water pollution. A variety of treatment strategies have been used to maximize dye deterioration process. Furthermore, because of its small size and high reactive nature, nanocomposites have attracted a lot of interest in the elimination of harmful dye pollution. In this present research work Methylene blue dye was selected for photocatalytic degradation using synthesized photocatalysts. In the presence of synthetic photocatalysts, we irradiated an aqueous solution of methylene blue dye with sunlight and UV radiation. This study compares photocatalytic methylene blue degradation in the presence of Poly (aniline-Co-Oaminophenol)/ ZnO nanocomposite and Polyazomethine/ZnO nanocomposites. The outcomes showed that Poly (aniline-Co-O-aminophenol)/ZnO nanocomposite has a higher photocatalytic productivity than Polyazomethine/ZnO nanocomposites.

A Comprehensive Review of Effective Adsorbents Used for the Removal of Dyes from Wastewater

Aim: The objective of the review paper aims to explore and to provide the insight of various low-cost adsorbents prepared and used in the removal of hazardous dye pollutants from the contaminated industrial effluents. Background: The major untreated discharge from the textile industries constitutes a wide range of organic contaminants with the enhanced concentration of biological oxygen demand and chemical oxygen demand inthe water bodies. Dyes are considered as the major water contaminants and this quest the researchers to adopt various technologies to remove the hazardous dye pollutants from the aquatic environment. Dyes are the chemical compounds that tend to adhere themselves with metal or salts by covalent bond formation or complexes by mechanical retention or physical adsorption so as to impart colours to which it is being applied. Objective: Numerous treatment methodologies which have been applied to the degradation of dyes. The current study has been focused on the distinct low cost and cost-effective adsorbents used in the removal of various dye pollutants. Also, the application of nanoparticles in the removal of the hazardous dye pollutants had received great interest because of its size and high reactive nature. Methods: The treatment technologies used in the removal of dye pollutants from wastewater have been listed as adsorption, coagulation, electrocoagulation, flocculation, membrane filtration, oxidation and biological treatment. Results: The complex structure of the dyes causes a great harmful impact on the aquatic environment. Though numerous treatment technologies have been applied, adsorption has been preferred by various researchers because of its cost-effective nature. Conclusion: The various adsorbents are used in the removal of cationic, anionic and non-ionic dyes. The different types of adsorbent from agricultural waste, activated carbons, nanomaterials and biomaterials have been discussed with the advantages and limitations.

Conformational & spectroscopic characterization, charge analysis and molecular docking profiles of chromone-3-carboxylic acid using a quantum hybrid computational method

The Spectroscopic profile of Chromone-3-Carboxylic Acid (abbreviated as C3CA) was examined using FT-IR, FT-Raman, UV, 1H and 13C NMR techniques. The geometrical parameters and energies attained from DFT/B3LYP method with 6–311++G (d,p) basis sets calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and assigned the fundamental vibrations on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The XRD data obtained from the computed geometric parameters shows that there is little deviation in the structure due to the substitution of the COOH group in the molecule. Using NBO study, the delocalization of the electron and the corresponding attraction between the orbitals shows that the lone pair transition has higher stabilization energy when compared with remaining atoms. The 1H and 13C NMR chemical shifts are calculated using GIAO method and the experimental chemical shifts were analysed with theoretical values which reflects better coincidence. The electronic properties, HOMO and LUMO energies, are performed with TD-DFT reproduces good with the experimental findings. Besides, frontier molecular orbitals (FMO), the high reactive nature of the molecule is identified with MEP and global reactivity descriptor analysis are performed. In addition, the molecular docking study was conducted, and results of the docking study identified the sugar phosphatase inhibitor activity of the target molecule (C3CA).

A comparative study of photocatalytic degradation of Rhodamine B using natural-based zeolite composites

Numerous treatment methodologies have been applied to the degradation of dyes. In addition, the application of nanocomposites in the removal of the hazardous dye pollutants had received great attention because of its size and high reactive nature. In this study, the Zeo-TiO2 and Zeo-ZnO composite photocatalysts were successfully synthesized by a simple co-precipitation method. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and N2 sorption-desorption isotherms (BET). Experimentally, in order to compare the performance of both catalysts, the photocatalytic activities were evaluated in the degradation of hazardous Rhodamine B dye in aqueous solution under UV-light. The results revealed that the Zeo-TiO2 composite exhibited superior photocatalytic performance with a degradation rate of 0.0559 min−1, which exceeded that of Zeo-ZnO composite by more than 3 times. For both of photocatalysis, superoxide radical (●O2−) and hydroxyl radical (●OH) dominates the degradation of RhB dye, while holes (h+) show a negligible contribution. Consequently, it can be revealed that the prepared natural-based zeolite photocatalysts can perform as potential composites in the degradation of organic contaminants under UV irradiation.

Effects of charged interfaces on electrolyte decomposition at the lithium metal anode

Lithium–Sulfur batteries are promising candidates to substitute conventional Li-ion batteries due to their higher energy density and reduced cost. However, several challenges related to the reactivity of the lithium metal anode have prevented this technology from becoming broadly commercialized. Lithium's high reactive nature leads to the continuous decomposition of the electrolyte and the formation of the solid-electrolyte interphase (SEI) layer. Thus, a comprehensive understanding of how the SEI film is formed is crucial to help elucidate improvements for this battery technology. In this work, we use density functional theory (DFT) based computational methods to investigate the effect of charged interfaces on the electrolyte degradation at the lithium anode. Several electrolyte mixtures were considered including 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) as solvents, and lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as salts. It is found that the extent of salt decomposition is higher when the interface is charged. In addition, two types of solvent reduction mechanisms are identified: C–O bond cleavage and radical attacks. Charge transfer and evolution analysis are characterized in detail. Finally, solvent decomposition reactions are found to become more thermodynamically favorable and their activation barriers to be diminished under the effect of constant potentials and electric fields.

Anti-Inflammatory, Anti-Diabetic, and Anti-Alzheimer’s Effects of Prenylated Flavonoids from Okinawa Propolis: An Investigation by Experimental and Computational Studies

Okinawa propolis (OP) and its major ingredients were reported to have anti-cancer effects and lifespan-extending effects on Caenorhabditis elegans through inactivation of the oncogenic kinase, p21-activated kinase 1 (PAK1). Herein, five prenylated flavonoids from OP, nymphaeol-A (NA), nymphaeol-B (NB), nymphaeol-C (NC), isonymphaeol-B (INB), and 3′-geranyl-naringenin (GN), were evaluated for their anti-inflammatory, anti-diabetic, and anti-Alzheimer’s effects using in vitro techniques. They showed significant anti-inflammatory effects through inhibition of albumin denaturation (half maximal inhibitory concentration (IC50) values of 0.26–1.02 µM), nitrite accumulation (IC50 values of 2.4–7.0 µM), and cyclooxygenase-2 (COX-2) activity (IC50 values of 11.74–24.03 µM). They also strongly suppressed in vitro α-glucosidase enzyme activity with IC50 values of 3.77–5.66 µM. However, only INB and NA inhibited acetylcholinesterase significantly compared to the standard drug donepezil, with IC50 values of 7.23 and 7.77 µM, respectively. Molecular docking results indicated that OP compounds have good binding affinity to the α-glucosidase and acetylcholinesterase proteins, making non-bonded interactions with their active residues and surrounding allosteric residues. In addition, none of the compounds violated Lipinski’s rule of five and showed notable toxicity parameters. Density functional theory (DFT)-based global reactivity descriptors demonstrated their high reactive nature along with the kinetic stability. In conclusion, this combined study suggests that OP components might be beneficial in the treatment of inflammation, type 2 diabetes mellitus, and Alzheimer’s disease.

Joining of AZ31 Mg alloy sheets by friction stir welding and investigating corrosion initiated failure

Recently magnesium (Mg) and its alloys have gained wide popularity as light weight metals for various structural applications. Welding of Mg by conventional methods is complex due to its high reactive nature which leads to oxidization or to catch fire during welding. The poor corrosion resistance of Mg is also an issue that needed to be considered while designing the structures particularly intended to use in highly corroding environments. In the present work, friction stir welding (FSW), a solid state joining technique was adopted to join AZ31 Mg alloy sheets and the corrosion initiated failure behavior of the weld joints was investigated. FSW was successfully carried out at different processing parameters. The microstructural observations clearly showed that the higher tool rotational speeds led to generate more amount of heat and further resulted grain growth at the weld joint. Hardness at the joint was observed as increased compared with that of base material which can be attributed to the smaller grain size. The specimens were cut across the weld joint and exposed to corroding environment (3.5% NaCl solution) for 24 h. The corroded specimens were then subjected to tensile testing and found that the base material has shown relatively better resistance to fracture compared with the weld joint. Hence from the results, it can be understood that corrosion initiated failure must be considered as a valid input while developing structures with Mg alloys.

Molecular docking, TG/DTA, molecular structure, harmonic vibrational frequencies, natural bond orbital and TD-DFT analysis of diphenyl carbonate by DFT approach

Vibrational spectral analysis of Diphenyl Carbonate (DPC) is carried out by using FT-IR and FT-Raman spectroscopic techniques. It is found that all vibrational modes are in the expected region. Gaussian computational calculations were performed using B3LYP method with 6–311++G (d, p) basis set. The computed geometric parameters are in good agreement with XRD data. The observation shows that the structure of the carbonate group is unsymmetrical by ∼5° due to the attachment of the two phenyl rings. The stability of the molecule arising from hyperconjugative interaction and charge delocalization are analyzed by Natural Bond Orbital (NBO) study and the results show the lone pair transition has higher stabilization energy compared to all other. The 1H and 13C NMR chemical shifts are calculated using the Gauge-Including Atomic Orbital (GIAO) method with B3LYP/6-311++G (d, p) method. The chemical shifts computed theoretically go very closer to the experimental results. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies and Molecular electrostatic potential (MEP) exhibit the high reactivity nature of the molecule. The non-linear optical property of the DPC molecule predicted theoretically found to be good candidate for NLO material. TG/DTA analysis was made and decomposition of the molecule with respect to the temperature was studied. DPC having the anthelmintic activity is docked in the Hemoglobin of Fasciola hepatica protein. The DPC has been screened to antimicrobial activity and found to exhibit antibacterial effects.

Investigating the morphology and reactivity of chars from Triplochiton scleroxylon pyrolysed under varied conditions

A gasifier may be optimised via a good understanding of the char formation, morphology and reactivity. The effects of varying the pyrolysis pressure and heating rate on the morphology of the char were investigated using a thermogravimetric analyser (TGA), scanning electron microscope (SEM) and micrograph spot analyser. The gasified chars were produced at heating rates of 5, 10 and 20°C/min and pressures of 0.1, 0.4 and 0.6MPa. All the chars have different degrees of apparent gasification reactivity. The random pore model (RPM) provided a better description of the experiment, with low average error values, θ, in all of the cases considered. The alkaline and alkaline earth metals (AAEM) in the tropical wood biomass Arere (Triplochiton scleroxylon) consist predominantly of calcium and could altogether be partly responsible for the noticeably high reactivity nature of the tropical Arere chars.

Rational Design of a Highly Reactive Ratiometric Fluorescent Probe for Cyanide

A novel highly reactive ratiometric fluorescent cyanide probe was judiciously designed based on 2-formylacrylonitrile moiety as a new cyanide reaction site. A DFT study was conducted to rationalize the extremely high reactivity nature of the ratiometric fluorescent cyanide probe.

PROCESSING OF WSi2 FILMS BY LOW PRESSURE CHEMICAL VAPOR DEPOSITION FROM IN SITU CHLORINATION OF METAL

An experimental investigation of WSi2 thin films by LPCVD from in situ elaborated metal chlorides is presented. The films composition and properties are studied as a function of input gas phase composition. Preliminary results show that WSi2 films can selectively grow on silicon. An attempt has been made to understand the results in terms of deposition conditions. As the feature of VLSl circuits continues to shrink below one micron, unmet requirements have driven industry to find alternative methods to achieve acceptable RC delay due to interconnection paths and to manage wafer topography issues. Because CVD tungsten and tungsten disilicide, WSi2, meet these requirements and offer diffusion barriers and improved electromigration resistance, the level of interest in this technology has mushroomed. At present the CVD WSi2 films are mainly processed by fluorine based reactive gases. However, additionally to the technical problems due to the high reactive nature of these gases, this process is rather delicate to optimize. An alternative solution may be the use of chlorides instead of fluorides as tungsten precursors. We have already illustrated the advantages of the chlorides by doing a comparative thermodynamic study of the two processes 111. We have proposed a controlled and reproducible way of production and transport of the tungsten chlorides. It consists of an in situ chlorination of a thermoregulated tungsten bed situated just above the substrate. We simulated and thermodynamically optimized the chlorination conditions and also analysed the resulting gaseous phase by mass spectrometry 121. Based on these two works we presented a first experimental study of the CVD of WSi2 at atmosperic pressure 131. This study showed the feasibility of the deposition from the chlorides and the qualitative agreement between the calculated and the

ChemInform Abstract: Synthesis of Fused Pyrimidines from Hydrazinopyrimidines and Their Related Compounds

Because of the high reactive nature of hydrazino group, hydrazinopyrimidines have widely been employed for the syntheses of various fused pyrimidines. Due to the growing number of publications, the present article reviews the literatures which appeared during the last two decades. This review also covers the utility of azo-, hydrazo- as well as azidopyrimidines for the construction of fused pyrimidines.

ヒドラジノピリミジンおよび関連化合物を用いる縮合ピリミジン類の合成

Because of the high reactive nature of hydrazino group, hydrazinopyrimidines have widely been employed for the syntheses of various fused pyrimidines. Due to the growing number of publications, the present article reviews the literatures which appeared during the last two decades. This review also covers the utility of azo-, hydrazo- as well as azidopyrimidines for the construction of fused pyrimidines.