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1.
In this study, we report a waste material-ground granulated blast furnace slag (GGBFS) as a low cost geopolymer, hybridised with ZnO to form a novel and efficient photocatalyst capable of discolouring textile wastewater. GGBFS is a waste material in an iron industry. Methylene blue was used as the probe dye and natural sunlight was used for activation of the photocatalyst. It was observed that under the experimental conditions, ZnGP-40 exhibited twice the discoloration efficiency than conventionally used ZnO or TiO2. This enhanced performance is majorly attributed to increased surface area of ZnO when strewn in the GGBFS matrix. The photocatalysts were characterized by SEM, TEM, PSA, TGA, BET and UV–Vis/NIR. The effect of photocatalyst loading, speed of agitation and solar insolation has also been studied. Since this study has been performed in direct sunlight, it exhibits a realizable application of solar energy in the treatment of wastewater.  相似文献   
2.
Artabotrys odoratissimus inhibitory effect on mild steel (MS) corrosion in 0.5 M H2SO4 solution has been assessed utilizing mass loss, electrochemical potentiodynamic polarization, and impedance spectroscopy techniques. The Artabotrys odoratissimus plant has a wide range of bioactive compounds. Phytochemicals were tested for ethanolic Artabotrys odoratissimus leaves extract (AOLE) using the FeCl3 test, Salkowaski's test, and others. Corrosion tests were conducted at varying inhibitor concentrations and temperatures. The inhibitory impact of AOLE on corrosion of MS was reported to improve with increasing concentration. Polarization experiments revealed that AOLE is a mixed kind of inhibitor and the inhibition efficacy w) for MS is 93.27% for 1.25 g/L AOLE. For Electrochemical impedance spectroscopy (EIS), maximal inhibitory efficacy w) was 91.62% due to AOLE adsorption on the MS surface. The obtained results using each methodology are highly consistent and closely resemble each other. The adsorption of AOLE molecules on an MS surface from the bulk of the solution causes the inhibitor's inhibition action, and the adsorption mechanism follows Langmuir adsorption isotherm. The computed ΔGadso values ranged between ?32.919 and ?33.520 kJ mol?1, implying a spontaneous and exothermic inhibitory action. The thermodynamic and activation parameters are often used to understand corrosion inhibition mechanisms. The comparison of corrosion product and pure extract FT-IR spectrum indicates the nature of AOLE adsorption on the MS surface. The surface morphology of MS samples was assessed using atomic force microscopy (AFM), scanning electron microscope (SEM), and contact angle techniques.  相似文献   
3.
Water plays a pivotal role in structural stability of supramolecular pigment assemblies designed for natural light harvesting (for example, chlorosome antenna complex) as well as their artificial analogs. However, the dynamic role of water in the context of excite-state relaxation has not been explored till date, which we report here. Using femtosecond transient absorption spectroscopy, we investigate the excited-state dynamics of two types of nano-scale assemblies of chlorophyll a with different structural motifs, rod-shaped and micellar assemblies, that depend on the water content. We show how water participates in excess energy dissipation by vibrational cooling of the non-thermally populated Qy band at different rates in different types of clusters but exhibits no polar solvation dynamics. For the micelles, we observe a bifurcation of stimulated emission line shape, whereas a positive-to-negative switching of differential absorption is observed for the rods; both these observations are correlated with their specific structural aspects. Density functional theory calculations reveal two possible stable ground state geometries of dimers, accounting for the bifurcation of line shape in micelles. Thus, our study elucidates water-mediated structure–function relationship within these pigment assemblies.  相似文献   
4.
The objective of this research work was to investigate the kinetics of esterification of acetic acid with n-butanol through the variation of experimental parameters. The reaction mixture was catalyzed heterogeneously by a sulfonated catalyst in batch mode of operation. The catalyst was prepared from abundantly available agro-waste, Cajanus cajan husk by chemical activation process, which produces a carbon-based solid catalyst with high surface area. The catalyst was characterized by a Brunauer-Emmet-Teller surface analyzer and Fourier transform infrared spectroscopy to know the surface morphology. Process parameters such as contact time, reaction temperature, and catalyst loading, which can influence the extent of conversion of reactants, were studied. Furthermore, the kinetic investigation was also carried out to estimate the kinetic parameters for uncatalyzed and catalyzed reaction using the second-order pseudo-homogeneous (P-H), Eley-Rideal (E-R), and Langmuir-Hinshelwood (LH) kinetic models for this research work. The kinetic parameters such as activation energy, preexponential factor, and the thermodynamic parameters such as enthalpy and entropy were estimated for uncatalyzed and catalyzed reactions using these three models. The process conditions were optimized for catalyzed and uncatalyzed reactions to obtain the maximum product yield by minimizing root mean square error of each experimental data using the MS-excel solver tool. Thus, this study reveals the high potential of an agro-waste, Cajanus cajan husk as raw material for the synthesis of catalyst. The results show that the E-R model is more appropriate for predicting the dynamic data of an esterification reaction, as the forward rate of reaction estimated using the E-R model are more modified than P-H and L-H models.  相似文献   
5.
A new third‐order WENO scheme is proposed to achieve the desired order of convergence at the critical points for scalar hyperbolic equations. A new reference smoothness indicator is introduced, which satisfies the sufficient condition on the weights for the third‐order convergence. Following the truncation error analysis, we have shown that the proposed scheme achieves the desired order accurate for smooth solutions with arbitrary number of vanishing derivatives if the parameter ε satisfies certain conditions. We have made a comparative study of the proposed scheme with the existing schemes such as WENO‐JS, WENO‐Z, and WENO‐N3 through different numerical examples. The result shows that the proposed scheme (WENO‐MN3) achieves better performance than these schemes.  相似文献   
6.
Research on Chemical Intermediates - In this paper we review the luminescence properties of Pr3+-doped CaTiO3 phosphors, the different methods of sample preparation, and characterization of the...  相似文献   
7.
The combination of acebrophylline (ABP), levocetirizine (LCZ) and pranlukast (PRN) is used to treat allergic rhinitis, asthma, hay‐fever and other conditions where patients experience difficulty in breathing. This study was carried out with the aim of developing and validating a reverse‐phase high‐performance liquid chromatographic bioanalytical method to simultaneously quantitate ABP, LCZ and PRN in rat plasma. The objective also includes determination of the pharmacokinetic interaction of these three drugs after administration via the oral route after individual and combination treatment in rat. Optimum resolution between the analytes was observed with a C18 Kinetex column (250 mm × 4.6 mm × 5 μm). The chromatography was performed in a gradient elution mode with a 1 mL/min flow rate. The calibration curves were linear over the concentration range of 100–1600 ng/mL. The intra‐ and inter‐day precision and accuracy were found to be within acceptable limits as specified in US Food and Drug Administration guideline for bioanalytical method validation. The analytes were stable on the bench‐top (8 h), after three freeze–thaw cycles, in the autosampler (8 h) and as a dry extract (?80°C for 48 h). The statistical results of the pharmacokinetic study in Sprague–Dawley rats showed a significant change in pharmacokinetic parameters for PRN upon co‐administration of the three drugs.  相似文献   
8.
Extraction power of solvent depends upon the physical properties of the system. Tri-n-butyl phosphate (TBP) in dodecane is a versatile solvent used in the nuclear fuel reprocessing like PUREX process. The study of physical properties like density, viscosity, interfacial tension and solubility for TBP–nitric acid–dodecane system will be helpful in carrying out different extraction studies during PUREX process. Thus, physical properties like density, viscosity, interfacial tension and solubility have been measured for TBP–nitric acid–dodecane system using pycnometer, viscometer, pendant drop method and high performance liquid chromatography respectively. It has been observed that density and viscosity increases but interfacial tension and solubility decreases with the concentration of TBP in dodecane–nitric acid system. Physical properties of 30 % TBP–nitric acid–dodecane system have also been studied in detail. All these studies will also be useful in stripping out dissolved TBP from the nuclear waste.  相似文献   
9.
In this article, we have devised a new reference smoothness indicator for third‐order weighted essentially non‐oscillatory (WENO) scheme to achieve desired order of convergence at critical points. In the context of the weighted essentially non‐oscillatory scheme, reference smoothness indicator is constructed in such a way that it satisfies the sufficient condition on the weights for the third‐order convergence. The goal is to construct a reference smoothness indicator such that the resulted scheme have to achieve the required order of accuracy even if the first two derivatives vanish but not the third derivative. The construction of such reference smoothness indicator is not possible through a linear combination of local smoothness indicators only. We have proposed a reference smoothness indicator to be of the fourth order of accuracy on three‐point stencil that contains the linear combination of the first derivative information of the local and global stencils. The performance enhancement of the WENO scheme through this reference smoothness indicator is verified through the standard numerical experiments. Numerical results indicate that the new scheme provides better results in comparison with the earlier third‐order WENO schemes like WENO‐JS and WENO‐Z. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   
10.
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