Quantum Chemical and Monte Carlo Simulation Studies on Inhibition Performance of Caffeine and Its Derivatives against Corrosion of Copper

Performance tests on caffeine’s corrosion inhibition properties and their derivatives against copper corrosion have been previously reported experimentally using gravimetric and electrochemical analyses. The test was able to measure the efficiency of their corrosion inhibition accurately. However, the caffeine and its derivatives’ structure patterns and coating mechanisms when interacting with metals during copper corrosion inhibition have not been explained in detail by experimental studies. In the present study, the theoretical density functional study (DFT), ab initio MP2, and Monte Carlo simulation approaches explain the problem. The geometrical and quantum chemical parameters of inhibitors were compared under normal and protonated conditions in the gas and aqueous environments. Theoretical studies can accurately determine the molecule’s geometrical parameters and successfully explain the quantum parameters of inhibitors. Molecular dynamics are applied to study the mechanism of interaction between inhibitors and metal surfaces in an explicit water molecule environment. The energy absorption of caffeine and its derivatives on metal surfaces was linear, with quantum parameters calculated from the density functional theory and an ab initio approach. Furthermore, these theoretical study results align with the previously reported experimental studies published by de Souza et al. The inhibition efficiency ranking of studied molecules preventing copper corrosion was caffeine > theobromine > theophylline. This theoretical approach is expected to bridge the gap in designing effective corrosion inhibitors.

A QUANTUM-CHEMICAL DESCRIPTORS OF CARBONIC ANHYDRASE CA(I) INHIBITION BY AROMATIC SULFONYL AMIDES

The quantum parameters of aromatic sulfonylamides are determined to describe their interaction with carbonic anhydrase at the theory level M06/6-311 ++G**(SMD). The molecular electrostatic potential on the nitrogen atom in sulfamides and Hirschfeld charge on this atom have been found to appear to be adequate and determinative descriptors of carbonic anhydrase inhibition.

Urdhva Tiryak Sutra Based Ancient Multiplication in Reversible Logic Circuits

The proposed work analyses the employment of an ancient mathematical approach for building an arithmetic logic unit. Dissipation of power is one of the major driving issues in VLSI design. With the assistance of reversible gates, the power dissipation and loss of information can be minimized. The speed and accuracy of the Arithmetic Logic Unit depends on the propagator. Employing the traditional mathematics sutras technique within the computation algorithm reduces the complexity, duration and power. Due to the effect of environmental factors on the digital circuits, parity conserving technique is incorporated for providing error detection ability. The proposed work deal with the design and analysis of 32 bit reversible multiplier using ancient sutras with and without parity conserving technique .The planned work is implemented on Xilinx ISE Spartan 6E series of FPGA and simulation results are obtained. By using Cadence EDA tool, power, area and delay are calculated. The quantum parameters are calculated manually for 32-bit reversible multiplier using ancient technique with and without parity conserving technique using Urdhva Tiryakbhyam sutra.

Estimating Antiwear Properties of Ionic Liquids as Lubricant Additives Using a QSTR Model

The antiwear properties of ionic liquids (ILs) as lubricant additives were studied with polyethylene glycol (PEG) used as the lubricant base oil. The quantum parameters of the ILs were calculated using a Hartree–Fock ab initio method. Correlation between the scale of the wear scar diameter and quantum parameters of the ILs was studied by multiple linear regression (MLR) analysis. A quantitative structure tribo-ability relationship (QSTR) model was built with a good fitting effect and predictive ability. The results show that the entropy of the ILs is the main descriptor affecting the antiwear performance of the lubricant system. To improve the antiwear performance of the lubricants, the entropy of the system should be decreased, reducing the system randomness and increasing the system regularity. A major influencing factor on the entropy of a system is the intra- and intermolecular hydrogen bonds present. Therefore, enhanced antiwear properties of lubricants could be achieved with a three-dimensional netlike structure of lubricant formed by hydrogen bonding.

Skew quasi cyclic codes over 𝔽q + v𝔽q

In this work, skew quasi cyclic codes over [Formula: see text], where [Formula: see text] are considered. The generating set for one generator skew quasi cyclic codes over [Formula: see text] is also determined. We discuss a sufficient condition for one generator skew quasi cyclic codes to be free. Furthermore, a BCH type bound is given for free one generator skew quasi cyclic codes. We investigate the dual of skew quasi cyclic codes over [Formula: see text]. We give a necessary and sufficient condition for skew cyclic codes over [Formula: see text] to contain its dual. Moreover, we construct quantum codes from skew cyclic codes over [Formula: see text]. By using computer search we give some examples about skew quasi cyclic codes and list some quantum parameters in the table.

Corrosion Inhibition Efficiency Of Nicotine Based On Quantum Chemical Study

The effect of substituents, electron donor groups (NH2, OH, CH2OH and CH3) and electron withdrawal groups (NO2, COOH, and Cl), to the efficiency of corrosion inhibition of nicotine has been studied using theoretical studies. The effect of substituents toward the efficiency of corrosion inhibition of nicotine based on quantum parameters (EHOMO, ELUMO, Egap, I, χ, dan ΔN). The efficiency of corrosion inhibition based on quantum parameters is NH2 > OH > CH2OH > CH3 > BN > Cl > COOH > NO2. The addition of electron donor group NH2 has the highest inhibitory efficiency of 99.79 %. In contrast, the presence of electron withdrawal group NO2 has the opposite effect.

Estudo teórico da eficiência de inibidores orgânicos de corrosão derivados do benzimidazol

The objective of this work was to evaluate the efficiency of inhibition the corrosion of two organic molecules derived from benzimidazole, specifically 2-mercaptobenzimidazole (2Mcb) and 2-phenylbenzimidazole (2Fb). The calculations were performed using the Density Functional Theory (DFT) at the B3LYP with 6-311+G(d,p) basis set. The quantum parameters correlated with the inhibition efficiency such as the highest occupied molecular orbital energy (EHOMO), the lowest unoccupied molecular orbital energy (ELUMO) , energy gap (ΔE), electronegativity (χ), hardness (η), the fractions of electrons transferred (ΔN), electrophilicity (ω) and Fukui indices, were calculated. Calculations were performed in aqueous medium in both protonated and non-protonated forms. Theoretical results were compared with experimental data and a good correlation was found between the chemical quantum parameters and the efficiency of inhibition of the molecules. DOI: http://dx.doi.org/10.30609/JETI.2018-5270