ABSTRACT
The present study reports the synthesis, characterization and corrosion inhibition effects of chitosan (CH) and its 5-chloromethyl-8-hydroxyquinoline derivative (CH-HQ) for mild steel in acidic medium. The synthesized CH-HQ was characterized using 1H NMR and FT-IR spectroscopic methods. Corrosion inhibition efficiencies of CH and CH-HQ were measured using electrochemical and chemical techniques. The surface protection ability of the inhibitor molecules was also ascertained by surface analysis, while computational study was used to further justify the adsorption tendencies of the molecules on mild steel surface. CH-HQwasobserved to exhibit better protection efficiency than CH, as the highest inhibition efficiencies were recorded to be 78% and 93% for CH and CH-HQ, respectively. Potentiodynamic polarization studies revealed that CH and CH-HQ are mixed-type corrosion inhibitors over the studied temperature range (298 K ± 1 to 328 K ± 1). SEM-EDS studies were performed to demonstrate the adsorption of CH and CH-HQ on the mild steel surface. Adsorption behavior of the CH and CH-HQ was also supported by UV-visible (UV-vis) spectrophotometric analyses. Monte Carlo simulations (MC) and density functional theory (DFT) calculations were carried out to corroborate the experimental results.
Subject(s)
Carbohydrates/chemistry , Chitosan/chemistry , Monte Carlo Method , Oxyquinoline/chemistry , Polymers/chemistry , Quantum Theory , Steel/chemistry , Corrosion , Dielectric Spectroscopy , Surface PropertiesABSTRACT
The adsorption and corrosion inhibition properties of two imidazole derivatives namely, 2-(4-chlorophenyl)-1,4,5-triphenyl-1H-imidazole (IM-Cl) and 1,4,5-triphenyl-2-(p-tolyl)-1H-imidazole (IM-CH3) for mild steel in 0.5 M H2SO4 solution are studiedby electrochemical and computational calculations. The results obtained from the electrochemical methods show that IM-Cl and IM-CH3imparted high resistance and behave as mixed type inhibitors. Inhibition efficiency (IE %) increases with the increase of inhibitors concentration to attain 96 % and 91% at 10-3 M of IM-Cl and IM-CH3 respectively. EISdatais analyzed to model the inhibition process through appropriate equivalent circuit model. Thermodynamic and kinetic parameters controlling the adsorption process are calculated and discussed. DFT calculations are carried out at the B3LYP levels of theory with 6-31G (d,p) basis stein gas and aqueous phase for neutral and protonated forms. Quantum chemical calculations section of the study provides enough calculation and discussion on the relationship between corrosion inhibition and global reactivity descriptors.
ABSTRACT
The Authors examined the epidemiological behaviour of endometrial carcinoma in the Province of Trieste from 1969 to 1980. In this period a European standard incidence of 14.33(0)/0000 was recorded. The most affected age group is 60 to 69, and the average age is 64 years. A clear increasing trend of this kind of neoplasia was recorded. This increase mainly occurs in younger age groups than those which presently are most affected.
Subject(s)
Uterine Neoplasms/epidemiology , Adult , Age Factors , Aged , Epidemiologic Methods , Female , Humans , Italy , Middle Aged , Uterine Neoplasms/pathologyABSTRACT
The epidemiological behaviour of the invasive cancer of the uterine cervix in the Province of Trieste is analysed. During this study period, 488 cases of this neoplasia were diagnosed with an incidence rate standardized for the European population of 20.25 degrees/0000. This value is within the average ones recorded in other geographic regions. The age group which is most affected is that from 60 to 64 years. By analyzing the overall incidence rate of the first two years if compared with the last two years of our study period, a 29% decrease is recorded, with an annual average decrease of 2.6%. This value is one of the highest reported in the literature. This decrease is recorded in the age groups over 40, while no decrease is recorded in women under age 40.
