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.
A chemical study was carried out to evaluate the efficiency of the liver enzyme concertation and uric acid level and its antagonists in the serum of the professors exposed to chemicals in the laboratories of the University of Samarra and their comparison with the healthy people. The research included 25 samples of the exposed professors and 20 samples as a group of officers.
The results of the current study showed a significant increase in the level of AST, ALT in the serum of professors exposed to chemicals compared to healthy people. The results showed no significant increase in
... Show MoreA graph is a structure amounting to a set of objects in which some pairs of the objects are in some sense related. The objects correspond to mathematical abstractions called vertices (also called nodes or points) and each of the related pairs of vertices is called an edge (also called link or line). A directed graph is a graph in which edges have orientation. A simple graph is a graph that does not have more than one edge between any two vertices and no edge starts and ends at the same vertex. For a simple undirected graph G with order n, and let denotes its complement. Let δ(G), ∆(G) denotes the minimum degree and maximum degree of G respectively. The complement degree polynomial of G is the polynomial CD[G,x]= , where C
... Show MoreBackground: Osteoid osteomaa benign tumor is unusual before the age of 5 or after age 30 and is more prevalent in men. The main symptom is pain, which is typically severe and responsible for nocturnal awakenings. The conditons usually diagnosed through radiological imagine and confirmed by Histopathology.
Objectives: To assess the effectiveness and the complications that had been risen during the surgical procedure of osteoid osteoma using en bloc resection.
Methods: (10) Patients diagnosed with osteoid osteomawere treated with enbloc surgical reseaction were included in this study.the study took place at Al Yarmouk teaching hospital.the from April 2017-october 2018 and included 10 patients..(7) male, (3) females.The mean age of th
The mechanical design of elevator elements is always performed by international standards. The engineer selects the appropriate elements of elevator according to catalogues without knowing scientific details. Therefore, a theoretical analysis is achieved at two operating conditions for guide rails (1) safety gear operation, and (2) running condition with the loads unevenly distributed on the elevator car. The guide rail is considered a continuous beam with variable supports. Then the British code is listed showing the equations used in it.
The theoretical equations showed that guide rails are never subjected to stress in simultaneous combined buckling and bending in the plane, where the bending moment is exerted. It is always a c
... Show MoreResearch summary
The researcher in theological sects finds that the controversial issues between the owners of the sects are many, filled with the books of the sects, articles and creeds, and when examining these books it became clear to us that the dispute is related, some of it is related to the meaning and some of it is related to the words and it is many, explained to us by rhetorical terminology such as guidance and delegation, Interpretation and others, and part of it is what is called the verbal disagreement, and sometimes it is by using common possible expressions of truth and falsehood, as in the saying of the Kharijites, “The judgment is only for God,” and some of it is related to something outside th
The present work is concerned with the finding of the optimum conditions for biochemical wastewater treatment for a local tannery. The water samples were taken from outline areas (the wastewater of the chrome and vegetable tannery) in equal volumes and subjected to sedimentation, biological treatment, and chemical and natural sedimentation treatment.
The Box-Wilson method of experimental design was adopted to find useful relationships between three operating variables that affect the treatment processes (temperature, aeration period and phosphate concentration) on the Biochemical Oxygen Demand (BOD5).
The experimental data collected by this method were successfully fitted to a second order polynomial mathematical model. The most fa
Objectives: to evaluate the role of conservative, decompression, spine fixation in management of closed spinal injury.
Methods: The study was conducted at Specialized Surgical hospital and Al-Kadhemayia Teaching Hospital, in the period between July 2003 and July 2005.The study included 61 patients categorized Into many groups according level of vertebral injury (cervical, cervicodorsal, dorsal, dorsolumbar, Lumbar and lumbosacral), type of injury (compressed fracture, burst fracture and fracture dislocation) And according the severity into three groups as G1( complete motor paralysis and sensory loss ) G2 ( complete motor paralysis and incomplete sensory loss) and G3 ( incomplete motor paralysis And incomplete sensory loss ).The metho
Objective(s): To assess the types of violence among adolescents in Baghdad City.
A descripƟve study which was using the assessment approach was conducted on purposive sample of 60 parents of
adolescent for identify types of adolescents violence in their families, was selected according to specific criteria for
participating in health education program towards adolescents' violence control in Baghdad city.
Methodology: A questionnaire was constructed for the purpose of the study. It was consisted of two parts; the first
part which included the parents' demographic characteristics for parents (sex, age, educational level and socioeconomic
status); the second part included types of adolescent violence that reported by par