• Journal of Electrochemical Science and Technology
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• v.10 no.1
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• pp.69-81
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• 2019

The corrosion inhibiting mechanism of Vietnam orange peel essential oil (OPEO) for mild steel in 1 N HCl solution was investigated elaborately. Corrosion inhibition ability of OPEO was characterized by electrochemical polarization, electrochemical impedance spectroscopy (EIS), and weight loss method. In the corrosive solution, OPEO worked as a mixed inhibitor and the inhibition efficiency of OPEO increased with the increase of its concentration. High inhibition efficiencies over 90% were achieved for the concentration of 3 - 4 g/L OPEO, comparable to that of 3.5 g/L urotropine (URO), a commercial corrosion inhibitor for acid media used in industry. By using adsorption isotherm models (Langmuir, Temkin and Frumkin), thermodynamic parameters of adsorption were calculated. The obtained results indicated physical adsorption mechanism of OPEO on the steel surface. The components responsible for the corrosion inhibition activity of OPEO were not only D-limonene, but also other compounds, which contain C=O, C=C, O-H, C-O-C, -C=CH and C-H bonding groups in the molecules.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2871-2876
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• 2022

The sensitivity of polymer-based capacitive relative humidity (RH) sensors after irradiation with neutrons, electrons and protons was measured. Degradation consists of the decreasing of the upper RH limit that can be measured. At the same time, low RH-level sensitivity is almost stable. After 30 krad of absorption dose, RH cut off is equal to 85% of max value, after 60 krad-40%. Degradation reduces after annealing which indicates high radiation sensitivity of the internal circuit in comparison to RH-sensing polymer film.

• Journal of the Korean Chemical Society
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• v.52 no.2
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• pp.124-132
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• 2008

effect of some furfural hydrazone derivatives (I -V) as corrosion inhibitors for C-steel in 3M H3PO4 solution in which M indicates mol/l has been studied using weight-loss and galvanostatic polarization techniques. A significant decrease in the corrosion rate of C-steel was observed in the presence of the investigated compounds. This study revealed that, the inhibition efficiency increases with increasing the inhibitor concentration, and the addition of iodide and thiocynate ions enhances it to a considerable extent. The effect of temperature on the corrosion behavior of C-steel was studied in the range from 30-60oC with and without 510-6 M investigated compounds using weight-loss method. Apparent activation corrosion energy (Ea*) and other thermodynamic parameters for the corrosion process were calculated and discussed. The polarization measurements show that the investigated compounds act as mixed-type inhibitors, but the cathode is more polarized when an external current was applied. The adsorption of these compounds on the surface of C-steel in 3M H3PO4 obeys Frumkins adsorption isotherm. The mechanism of inhibition was discussed in the light of the chemical structure of the investigated compounds.

• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.123-132
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• 2017

Nowadays, many people suffer from stress because of their jobs, studies, traffic, etc. Daily stress may cause many diseases (Garrett, 1991). One of the methods for reducing stress is experiencing a natural environment (Frumkin, 2001). Cibodas botanical garden (CBG) is one of the most famous travel destinations in Bogor, Indonesia. CBG has the potential for tourism activities. However, an economic assessment is required to verify their sustainability. The research objectives of this study were to identify the characteristics of tourism utilization in CBG, to analyze the economic tourism value of CBG, and to measure the effectiveness of traveling to a natural environment for reducing stress. The research method used was the survey. This study used three data analysis methods: (1) descriptive analysis which was used to identify the characteristics of tourists, (2) travel cost method (TCM), and (3) contingent valuation method (CVM). Results showed some differences in the characteristics of foreign and domestic tourists respondents in age, educational background, income level, number of dependents, and the frequency of their visits. CBG has a high economic value, amounting to IDR (Indonesian Rupiah) 5,508,932,605,405 or approximately USD (United State Dollar) 413,000,000. WTP (Willingness to Pay) of domestic tourist respondents was IDR 29,702 or USD 2.2 per visit, while the value of foreign tourist respondents reached IDR 39,700 or USD 2.9 per visit. Respondents found it preferable to pay more for tickets (WTP value) than to buy medication to reduce their stress.