Analisis Termodinamika dan Kinetika Nanopartikel Karbon (C-Dot) dari Buah Durian Sebagai Inhibitor Korosi Tembaga

Corrosion is a physical interaction between the metal and its environment, which results in changes in the metal's properties due to chemical or electrochemical reactions. The corrosion rate can be reduced by adding a corrosion inhibitor. Uses of nanotechnology for corrosion prevention is one of the first technical because almost made structures rely on the stability of a 1–2 nm thick passive film which provides stability to the underlying material. Herein we report the thermodynamic and kinetic analysis of carbon-dots from Durian as inhibitor copper corrosion. To test the anticorrosive performance and analyze thermodynamic properties in its role as a corrosion inhibitor on copper using potentiodynamic polarization. The thermodynamic-kinetic parameters of corrosion obtained values of H‡ = 60.44 kJmol-1, ΔS‡ = -73.9 kJmol-1, and ΔG‡ = 82.83 kJmol-1, show that the attendance of C-dot as a corrosion inhibitor causes a non-spontaneous reaction rate to be proven by increasing spontaneity (ΔG‡). The value of activation energy samples was higher than the blank, indicates the presence of C-dot effective to reduce the rate of corrosion of the metal.

Corrosion Inhibition Mechanism of Steel Reinforcements in Mortar Using Soluble Phosphates: A Critical Review

The corrosion inhibition mechanism of soluble phosphates on steel reinforcement embedded in mortar fabricated with ordinary Portland cement (OPC) are reviewed. This review focuses soluble phosphate compounds, sodium monofluorophosphate (Na2PO3F) (MFP), disodium hydrogen phosphate (Na2HPO4) (DHP) and trisodium phosphate (Na3PO4) (TSP), embedded in mortar. Phosphate corrosion inhibitors have been deployed in two different ways, as migrating corrosion inhibitors (MCI), or as admixed corrosion inhibitors (ACI). The chemical stability of phosphate corrosion inhibitors depends on the pH of the solution, H2PO4− ions being stable in the pH range of 3–6, the HPO42− in the pH range of 8–12, while the PO43− ions are stable above pH 12. The formation of iron phosphate compounds is a thermodynamically favored spontaneous reaction. Phosphate ions promote ferrous phosphate precipitation due to the higher solubility of ferric phosphate, thus producing a protective barrier layer that hinders corrosion. Therefore, the MFP as well as the DHP and TSP compounds are considered anodic corrosion inhibitors. Both types of application (MCI and ACI) of phosphate corrosion inhibitors found MFP to present the higher inhibition efficiency in the following order MFP > DHP > TSP.

Adsorption of Toxic Heavy Metal Methylmercury (MeHg) on Germanene in Aqueous Environment: A First-Principles Study

We perform first-principles calculations to investigate the adsorption process of methyl mercury (MeHg) on germanene with the presence of water molecules. We calculate the formation energy and density of states to determine the effect of the adsorption of MeHg on the structural and electronic properties of germanene. Our results show that MeHg is chemisorbed on germanene through a spontaneous reaction. The calculated formation energy of the system is -1.61 eV. We also carry out charge distribution and charge transfer calculations based on the Mulliken model to understand the adsorption mechanism of MeHg.

Prediction of Europium Retention in Perovskite: Potential Candidates for an Engineering Barrier in the Disposal of Radioactive Waste

Perovskites, such as tausonite, are crystalline metal oxides with excellent optical and photocatalytic properties and have also been used successfully in the retention of metals, simulating the isotopes of uranium and plutonium. In this work, different pseudo-order and thermodynamic models were studied to achieve the prediction of the sorption of Eu3+ (chemical analogous for actinides) in tausonite. The effects of gamma irradiation and temperature on the structural characteristics of the material were determined, as an additional step in the evaluation of material as an engineering barrier in the disposal of radioactive waste. The results obtained show that the tausonite is resistant to the gamma irradiation and thermal energy. Likewise, it was possible to determine that europium sorption occurs through an exothermic and spontaneous reaction, as well as through the formation of surface complexes, where Eu3+ ions bind to sites on the tausonite by dipole-dipole interaction. Furthermore, it was shown that the sorption mechanism is influenced by diffusive phenomena, which participate in the formation of surface complexes. Additionally, a new sorption model with respect to pH was proposed, which allowed determining the physical parameter π. The evidence obtained suggests that π is a physical parameter that relates pH to an optimal value and could explain the equilibrium between the surface complexes that tausonite forms with europium. Likewise, the evidence suggests that 50 kg of tausonite would have the capacity to retain at least 26.59 g of alpha-emitting radionuclides, equivalent to a waste package (900 kg) with a maximum activity of 4000 Bq/g.

Medzikultúrny dialóg v súčasnej slovenskej dráme a divadle

The study deals with the possible inspirations from the external environment being the part of works by Karol Horák which undergo a creative transformation and produce a new aesthetic quality on the level of text, as well as the on the level of new staging forms or genesis of a completely new autochthonic theatre form (authorʼs theatre, postmodern theatre, medial theatre, happenings, performances, site-specific, etc.) There was a continuous pulsation among Slovak national theatre culture, or rather metonymically understood Prešov´s regional student theatre, and American (Living Theatre of J. Becka and J. Malinova, Schumannʼs Bread and Puppet, etc.), Polish (Kantorʼs Cricot 2, Grotowskiʼs Theatre Laboratory, Raczakʼs Theatre of Eighth Day, Mądzikʼs Plastic scene, Słupczynskiʼs Theatre Studio of Těšín, the Theatre Academy of Movement, Cracowian KTO, etc.) and Czech provenance (Theatre Orpheus Prague, Theatre X Brno, Theatre under Drain Pipe Ostrava, Quite Small Theatre Litvinov, Theatre on the Periphery, Prague, Quidam Brno, etc.) They have the form of a rational as well as a spontaneous reaction to the external stimulus which often acquired a form with surprisingly authentic aesthetic value. This value usually represented the latent affinity with the original stimulus and it often created an authentic theatre artefact with respect to the recipient having the peculiar status within the national context (e.g. Džura [1968], Démon [1967], Fragmenty [1974], Živý nábytok [1975], Tip-top biotop [1976], Materstvo [2011], Človek etudový alebo Konšpirácia alebo Od skúšky k predstaveniu [2013] etc.) This was the way how one wing of Slovak theatre tried to balance falling short of the European or world context.

Kinetic, Thermodynamic Studies for Photo Degradation of Glibinclamide Drug

In this work the photo degradation of glibinclamide is studied by UV light and different concentrations using solvents (water and ethanol) and different times. The reaction kinetic is studied and found that the photo degradation reaction of glibinclamide is (first-order) reaction and the thermodynamic properties (ΔHo, ΔSo and ΔGo) for glibinclamide were calculated and it was found to be (endothermic and spontaneous reaction).

Thermodynamic analysis on disproportionation process of cyclohexylamine to dicyclohexylamine

This work deals with a study of the effect of temperature on the cyclohexylamine disproportionation to dicyclohexylamine, conjointly with the thermodynamic analysis of this process. The laboratory experiments were carried out in a glass tubular continuous-flow reactor in a gaseous phase at the reaction temperature 433–463 K over a nickel catalyst. The results show, that the temperature has a trifling effect on equilibrium conversion of cyclohexylamine. However, temperature affects the formation of hydrocarbons, benzene and cyclohexane, and dehydrogenation products of dicyclohexylamine, i.e. N-cyclohexylidenecyclohexanamine and N-phenylcyclohexylamine. The latter one is the dominant product of dicyclohexylamine dehydrogenation. The disproportionation of cyclohexylamine has slightly exothermic character. At the experimental reaction temperature range, the cyclohexylamine disproportionation is spontaneous reaction and other reactions of this process are non-spontaneous.

Indonesia Kris Representation on Virtual YouTuber “Anya Melfissa” Visual Identity

The rapidly evolving motion capture technology has made it possible to solve online identity problems with the medium of moving character design known as Virtual YouTuber. Spontaneous reaction in Livestream media can make fictional character feels real through a virtual avatar. As such, anthropomorphism representation can be used and Anya Melfissa is a Virtual Youtuber whose moe anthropomorphism of Indonesia Keris. However, the visual identity of Indonesia Kris is hard to find by most people and the problem is interesting to study using the theory of semiotics, anthropomorphism, and kris visual identity. The method used to analyze Anya Melfissa’s character design will use visual text analysis to identify its visual elements such as icon, index, and symbol. The results of the analysis show that Anya Melfissa’s character design has a kris visual identity which is at the level of thirdness in Peirce’s semiotics theory. The conclusion obtained from the kris representation in Anya Melfissa’s character design is proven to exist and requires a deeper level of understanding of Indonesian kris itself.