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.
Zakat funds may be invested by the owner or his agent, because there is a delay in the investment, and such delay may harm the beneficiaries.
The scholars agreed on the permissibility of investment if it is received from those who are entitled to zakat after it is received, because if zakat reaches their hands, they become wholly owned by them, and therefore they may dispose of it as the disposition of the owners in their property, like all other permissible acts that are permissible according to shariah. What you will see in the folds of the search, God willing).
The issue of epistemology is one of the theological issues that were and still is a relentless pursuit of knowledge, knowing the true knowledge of certainty. Therefore, it formed a main focus because of its great importance expressing the deep desire of the human soul to explore the self and reality and answer all the questions that it may raise. Knowledge is the highest function. For man to exist.
Therefore, the establishment of epistemology was general in knowledge, a characteristic that was distinguished, as it is an ancient and renewed subject that is still being raised and raised, although there are many methods of treating it and sacred solutions to it. To finally prove its potentia
... Show Morein the present investigation new eight poly esrers as schiff bases wich containing pendant imine group were synthesized by treatment of poly acryloyl chlodire with ethanol amine group were synthesized by treatment of poly acryloyl chloride with ethanol
Rifampicin is the drug of choice in treatment of tuberculosis. Also, it is effective in treatment of various bacterial infections.This study was carried out to prepare a stable suspension for rifampicin through preparation of different formulas of rifampicin aqueous suspension either as ready to use or as granular powder to be reconstituted.The selected formula (A) was evaluated and compared with commercial brand of rifampicin (Rifactine®) as a reference through measuring their dissolution rates and other physical properties.The results indicated that the selected formula had better dissolution rate compared with the reference suspension and the rheogram showed that the selected formula was less
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Background : Bone infections is one of the most challenging orthopaedic complications, with considerable morbidity. There is significant impact on the life of the patients; socially, financially, physically, and mentally and it could be a limb-threatening complication. Osteomyelitis is a bone infection usually caused by bacteria, including mycobacteria, but mainly Staphylococcus aureus which is the most commonly responsible bacteria . Aim of study: To evaluate our management policy of chronic osteomylitis (C.O.M).
Methods : 32 patients presented with different types &forms of chronic osteomyelitis in many sites of long & flat bones such as tibia , femur, ,humerus ,iliac bones and knee joint , which are not response to previous
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Background: Chondrosarcoma is the second most frequent primary malignant tumor of bone. It is considered relatively an uncommon tumor. Generally it is not common for chondrosarcoma to attend huge size; however, one type was described as mesenchymal chondrosarcoma of low grade cartilaginous cells, with female predominance which can grow to exceptionally large size. Case Presentation: We report a case of Chondrosarcoma, in 30 years old woman of 4 years duration, with a huge mass (weighted 16 Kg) and roughly measured 40x30 x20cm, around the right shoulderInvestigations: Repeated MRI of the shoulder and trunk revealed a clear plane of cleavage between the tumor mass and the chest and abdominal walls and absence of invasion of the abdomen. Ul
... Show MoreBy using the deacetylation method, chitin is converted into bioproduct chitosan. Deacetylation can be accomplished using chemical or biological mechanisms. Due to its biocompatibility, nontoxicity, biodegradability, natural origin, and resemblance to human macromolecules, it is useful in medicine. Chitosan may have antibacterial and antioxidant properties. Additionally, it could be used in biotechnology, agriculture, gene therapy, food technology, medication delivery, cancer therapy, and other fields. The objective of the current review was to list the most significant applications of Chitosan in the biomedical field.
