Catalytic removal of the S-content from thiophene is a central step in efforts aiming to reduce the environmental burdens of transportation fuels. In this contribution, we investigate the hydrodesulfurization (HDS) mechanisms of thiophene (C4H4S) over γ-Mo2N catalyst by means of density functional theory (DFT) calculations. The thiophene molecule preferentially adsorbs in a flat mode over 3-fold fcc nitrogen hollow sites. The HDS mechanism may potentially proceed either unimolecularly (direct desulfurization) or via H-assisted reactions (hydrogenation). Due to a sizable activation barrier required for the first Csingle bondS bond scission of 54.6 kcal/mol, we predict that the direct desulfurization to contribute rather very insignificantly in the HDS mechanism. Transfer of adsorbed hydrogen atoms on the γ-Mo2N surface to the thiophene ring substantially reduces activation barrier required in the Csingle bondS bond scission to only 24.1 kcal/mol in a process that affords an adsorbed C4H6* species and an S atom. Further hydrogenation of the unsaturated C4H6* produces 2-butene. Kinetics and thermodynamics attributes dictate the occurrence of partial rather than full hydrogenation of C4H6*. Calculated rate constants for all individual steps could be utilized to construct a robust kinetic model for the overall HDS process. Estimated conversion values of thiophene predict 50–70% consumption of thiophene at 700 K and low values of gas hourly space velocities. Reaction routes and kinetic parameters provided herein are useful to design stand-alone γ-Mo2N-based catalysts for applications entailing partial hydrogenation and hydrodesulfurization of severely contaminated S-fuels.
The present study was conducted to evaluate the effect of different inhibitors on the corrosion rate of aluminum in 50% (v/v) ethylene glycol solution at 80°C and pH 8.0 in which the electrochemical technique of linear sweep voltammetry was employed to characterize each inhibitor function and to calculate the corrosion rate from Tafel plots generated by a computer assisted potentiostat.
It is found that both sodium dichromate and borax reduces the corrosion rate by polarizing the anodic polarization curve while sodium phosphate, potassium phosphate, and sodium benzoate reduces the corrosion rate by polarizing both the anodic and cathodic polarization curve.
When inhibitor concentration increases from I g/l up
... Show MoreJoseph Curtis wrote in his book (Introduction to Semiotics narrative and rhetoric) on the development of a semiotic project in exploring the meaning of communion. The book is rich in theoretical and analytical benefits both in the approach of texts and in the pursuit of letters in search of mechanisms of scriptural and scriptural generation and mechanics in narrative production, especially as the book offers exercises that help to assess the distance separating the narrative spread from the sin of the text, for the semiotics, Refers to the theoretical developments of the science of relations, through the combination of conventional definitions and the representative and comparative limitations, to provide an approach to the application o
... Show MoreAleksandr Isayevich Solzhenitsyn was born in 1918 in Kislovodsk. His father was educated, and despite his peasantry origin, he got a university degree. Unfortunately, however, Solzhenitsyn could not recognize his father, for he died before his birth.
Solzhenitsyn was accused of being an opponent to the Soviet Union due to his activities of that time. He was exiled to a forced labour camp for eight years, on the surroundings of Moscow. He spent three years in Kazakhstan, and was sent to the life exile. He was set free in 1956. He worked as a teacher in in rural schools in Vladimir and then in Rezhran.
His greatest works were in the reign of Kherchov, and in 1962 appeared his story under the title of "One day in
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Cerium (III), Neodymium (III) and Samarium (III) Complexes existent a wide range of implementation that stretch from their play in the medicinal and pharmaceutical area because of their major significant pharmacological characteristic such as antifungal, anti-cancer, anti-bacterial ,anti-human immunodeficiency virus ,antineoplastic, anti-inflammation,inhibition corrosion,in some industrial (polymers, Azo dye).It is likely to open avenuesto research among various disciplines such as physics, electronics, chemistry and materials science by these complexes that contain exquisitely designed organic molecules.This paper reviews the definition, importance and various applications of Cerium (III), Neodymium (III) and Samarium (III) Complexes anddi
... Show MoreThis study has sought to explore the Yemeni online news websites’ treatment of the tropical storm “Luban” which hit the coasts of al-Mahra governorate, and other parts of the Yemeni Eastern and Southern governorates in October 2018. The study also examined how the Yemeni news websites covered the disaster on the basis of the problematic situation model. The study’s findings revealed a form of logical balance in distributing the coverage of the disaster in its different phases. The coverage was a bit more focused on the disaster phase than the pre- and post-disaster phases. Additionally, the websites paid more attention to precautionary measures and the disaster’s humanitarian and material losses. The findings reveal that the ne
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Jurisprudential rulings were not once restricted to anyone. Even if some prominent imams were famous in one science, this does not mean that some of them were not very knowledgeable and well versed in another science, but he did not know much about it, given his fame in the first science in which he emerged. It prevailed over him until he became known only through him, and there are a large number of these people, and among them is our imam, the great critic Yahya bin Ma’in, may God be pleased with him. Many people, and even scholars, know about him except that he is the only imam in jarh and ta’deel, and on his words and the words of his strike are relied upon. In terms of the authenticity and weakness of the hadith, he is in this f
... Show MoreThe charge transfer at C23H17F8N8O2PRu, C44H30BF4N5O4Ru, C56H52CL5N5OOsP2 and C76H88F80N24O11P10Ru4 nitrosyl complexes are investigation and studies theoretically using the quantum consideration. Charge transfer behavior largely rely to the electric properties of nitrosyl complexes system whose depending on the main important parameters for the transmission rate constant such that: orientation transition energy, overlapping coupling coefficient, driving force energy, height barrier and Temperature T (K). Data results have been evaluated using a MATLAB program. Results show that rate of charge transfer increases due to increases the orientation transition energy.
Epoxy resin has many chemical features and mechanical properties, but it has a small elongation at break, low impact strength and crack propagation resistance, i.e. it exhibits a brittle behavior. In the current study, the influence of adding kaolin with variable particle size on the mechanical properties (flexural modulus E, toughness Gc, fracture toughness Kc, hardness HB, and Wear rate WR) of epoxy resin was evaluated. Composites of epoxy with varying concentrations (0, 10, 20, 30, 40 weights %) of kaolin were prepared by hand-out method. The composites showed improved (E, Gc, Kc, HB, and WR) properties with the addition of filler. Also, similar results were observed with the decrease in particle size. In addition, in this study, mult
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Beta Distribution
Abstract
Gamma and Beta Distributions has very important in practice in various areas of statistical and applications reliability and quality control of production. and There are a number of methods to generate data behave on according to these distribution. and These methods bassic primarily on the shape parameters of each distribution and the relationship between these distributions and their relationship with some other probability distributions. &nb
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The photoconductivity and its dependence on light intensity have been investigated in a-Ge20Se80 thin films as a function of temperature between (293–323)K. The result showed that the photoconductivity and photosensitivity increase with increase of annealing temperature. This behavior is interpreted in terms of the dispersive diffusion –controlled recombination of localized electrons and holes.