Exploring deep insights into the interaction mechanism of a quinazoline derivative with mild steel in HCl: electrochemical,DFT, and molecular dynamic simulation studies

A novel quinazoline derivative, 3-cyclopropyl-3,4-dihydroquinoline-2(1H)-One (CPHQ), was successfully designed and synthesized. Then, its corrosion inhibition behavior on carbon steel (CS) surface in 1.0?M HCl at different temperatures was investigated using chemical, electrochemical and theoretical techniques. The experiments confirmed that the studied inhibitor shows inhibition efficiency as high as 95% even at very low concentration of 5?×?10^?3 M. To ascertain the nature of adsorption of CPHQ molecules on CS surface, Langmuir adsorption isotherm model was best fitted. From potentiodynamic polarization (PDP) calculations, it was concluded that the CPHQ acted as a mixed type corrosion inhibitor. Electrochemical impedance spectroscopy (EIS) studies revealed that increase in CPHQ concentration, resulted in an increase in the polarization resistance with a simultaneous decrease in the double-layer capacitance values. PDP tests were also performed to understand the corrosion behavior of CS as a function of temperature without and with varying concentrations of CPHQ, at temperatures 303, 313, 323, and 333?K. It can be concluded that the corrosion inhibition effect was dependent on the concentration of the inhibitor and the solution temperature. In order to understand the basic insights of the action mode of CPHQ molecules, Density Functional Theory (DFT) method, and Molecular Dynamic (MD) simulations were also employed on the optimized structure of CPHQ.     

Development of gallic acid sensors based on polyimide-modified platinum electrode

A series aromatic polyimide (PI) membranes in the form of permselective films was synthesised from different dianhydrides with two diamine monomers for gallic acid (GA) measurement. The obtained PI films were examined by Spectroscopic techniques, Scanning Electron Microscopy (SEM) and thermal analysis techniques and then used to fabricate the selective films on the modified electrode. Because of their excellent film properties, as the permselective polymeric membranes were used for determination of GA in the presence of various interferences and real sample. The PI-1-modified Pt electrode showed a very high R-value (0.9935) and reproducibility for GA determination, as well as high selectivity.     

Aloe vera-based antibacterial porous sponges for wound dressing applications

Journal of Porous Materials - The antibacterial sponges with high macroporosity, high interconnectivity and high biocompatibility is a significant concern for wound healing applications. In this...     

Natural-based polymers for antibacterial treatment of absorbent materials

In this study, polypropylene (PP) nonwoven fabric which can be used as topsheet layer of an absorbent hygienic product was modified by natural based antibacterial agents. Antibacterial herbal agents (cinnamaldehyde, geraniol, phenylethyl alcohol) were sprayed by ethanol or applied by means of polylactic acid (PLA) and polycyclohexene oxide (PCHO) based polymers prepared by three different chemical methods. Characterization of synthesized materials was conducted via thermogravimetric analysis (TGA), differential thermal analysis (DTA), and scanning electron microscopy–energy dispersive X–ray spectroscopy (SEM-EDX). Besides characterization, antibacterial and pH buffering performances of antibacterial polymers alone and on PP fabric were tested by antibacterial and pH tests. Effects of antibacterial treatments on air permeability and absorption period of nonwoven fabrics were also analyzed. According to the results, biopolymers changed the thermal stability of PP nonwoven fabric. Antibacterial performances can be ranked as cinnamaldehyde, geraniol, and phenylethyl alcohol from the best. Besides a slight decrease about liquid absorption performance, all of the treated topsheet fabrics are sufficient for an absorbent hygienic product. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48302.     

Equivalent circuit for capacitive micromachined ultrasonic transducers to predict anti-resonances

Equivalent circuit models have been long used to evaluate the dynamics of the capacitive micromachined ultrasonic transducer (CMUT). An important parameter in the characterization of a CMUT is the anti-resonance frequency, which limits the immersion bandwidth. However, there is no equivalent circuit model that can accurately determine the anti-resonance frequency of a membrane. In this work, we present an improved lumped element parametric model for immersed CMUT. We demonstrate that the proposed equivalent circuit model accurately predicts anti-resonance and higher order mode frequencies, in addition to that of the fundamental mode. The proposed circuit model is in good agreement with device characteristics calculated using the finite element method and experimentally measured data.

     

Utilization of lignite ash in concrete mixture

In this article 11 ashes from various Turkish lignite sources were studied to show the effects upon lignite ash quality for use as a mineral admixture in concrete. The lignite ashes were classified into two general types (Class A and Class B) based on total of silica, alumina, and iron oxide. Total content of the three major oxides must be more than 50 % for Class A lignite ash and more than 70 % for Class B lignite ash. When 25 % of the cement was replaced by LA-1 (Class A) lignite ash, based on 300 kg/m³ cementitious material, the 28-day compressive strength increased 24.3 % compared to the control mix. The optimal lignite ash replacement was 25 % at 300 kg/m³ cementitious material.     

Bio-/Environment-Friendly Cationic Gemini Surfactant as Novel Corrosion Inhibitor for Mild Steel in 1 M HCl Solution

Bio-/environment-friendly cationic gemini surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy)dichloride, referred to as 16-E2-16, was synthesized and characterized. Corrosion inhibition effects of 16-E2-16 on mild steel (MS) surface in 1 M HCl solution at 30, 40, 50 and 60 °C were evaluated using gravimetric analysis, potentiodynamic polarisation and electrochemical impedance spectroscopy measurements. The nature of the protective inhibitor film formed on the MS surface was analysed by SEM, EDAX and FT-IR, while TGA was used to assure the thermal behaviour and stability of the film at high temperature. The formation of [inhibitor-Fe²⁺] on the surface of MS was confirmed by UV–visible spectroscopy. The inhibition efficiency of the studied inhibitor increased with increasing concentration and solution temperature. The compound behaved as a mixed type inhibitor and acted by blocking the electrode surface by means of adsorption obeying the Langmuir adsorption isotherm. Surface active properties and corrosion inhibition effects of 16-E2-16 in the presence of inorganic (NaI) and organic (NaSal) salts were also investigated and are discussed. Density functional theory calculations have been carried out to correlate the efficiency of the compound with its intrinsic molecular parameters.     

Photoluminescence characterization and heat treatment effect on luminescence behavior of BaTa2O6:Dy3+ phosphor

Undoped and Dy³⁺‐doped barium tantalate phosphors were synthesized by the solid‐state reaction method at 1425°C. Also, 10 mol% Dy³⁺‐doped BaTa₂O₆ was sintered between 1150 and 1425°C in order to determine temperature effect on structural and luminescence properties. Afterwards, they were characterized by XRD, SEM‐EDS and photoluminescence (PL) analyses. PL spectra exhibited the excitation peaks between 300 and 440 nm. Two typical emissions were observed at 486.2 nm (blue) and 577.7 nm (yellow) due to the ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→⁶H_13/2 transitions, respectively. Emission intensities increased with increasing doping concentration of Dy³⁺ up to 10 mol% and then decreased due to the concentration quenching effect. Moreover, depending on the increase in heat treatment temperature, the intensity of emission reached maximum at 1425°C. The calculated CIE chromaticity coordinates of phosphors located in the white light region.