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Islamabad, Pakistan

Waris G.,Quaid-i-Azam University | Siddiqi H.M.,Quaid-i-Azam University | Florke U.,University of Paderborn | Hussain R.,NESCOM | Butt M.S.,Quaid-i-Azam University
Acta Crystallographica Section E: Structure Reports Online

The molecule of the title compound, C19H13Br2N3O2, lies about a twofold rotation axis. The benzene ring makes dihedral angles of 8.9 (2) and 16.4 (2)° with the central pyridine ring and the second benzene ring, respectively. An intramolecular N - H⋯N contact occurs. In the crystal, molecules are connected by pairs of N - H⋯O hydrogen bonds into chains along the c axis. © 2013 Waris et al. Source

Bahadar A.,National University of Sciences and Technology | Khan M.B.,National University of Sciences and Technology | Mehran T.,NESCOM
Industrial and Engineering Chemistry Research

Diminishing fossil fuel resources, unstable/increasing prices of oil, environmental issues, global warming/climatic shifts, and allied problems have led the world to focus on alternate, environmental friendly, and renewable energy sources. Among many experimental candidates, production of biodiesel from Jatropha curcas L. has gained significant importance. More than 40 countries in the world are evaluating the potential of using this pure plant oil for manufacturing diesel. USEPA's action sets the 2013 volume at 1.28 billion gallons under the Energy Independence and Security Act of 2007. With this premise, it is imperative to identify innovative technologies to handle Jatropha biomass and its efficient oil extraction for economical biofuel production. This study is aimed to make efficient screw expeller to cater massive Jatropha biomass for its oil extraction. A computational flow dynamics (CFD) simulation is performed to estimate the pressure developed inside the barrel through screw pressing when the feedstock is Jatropha seed. This CFD study has helped to determine the optimum values of important operating variables like rotations per minute (rpm), backpressure caused by frictional forces, and effect of changing feed flow rate on the performance of the expeller. The performance of the expeller is measured by power consumption, yield, and efficiency. Experimental validation of the simulation is used to improve oil expeller for Jatropha seed by fabricating the expeller after the analysis of design by ANSYS FLUENT codes. An oil yield in excess of 98%, as compared to a maximum 75% for existing screw expellers, was achieved in practical runs which is very promising. © 2013 American Chemical Society. Source

Nigar A.,Quaid-i-Azam University | Akhter Z.,Quaid-i-Azam University | McKee V.,Loughborough University | Hussain R.,NESCOM
Acta Crystallographica Section E: Structure Reports Online

The asymmetric unit of the title compound, C17H 18N2O4, contains two independent molecules (A and B) differing principally in the conformations of the alkyl chains, anti for molecule A and gauche for molecule B. The dihedral angles between the aromatic rings are 82.51 (6) and 82.25 (6)° in the two molecules. In the crystal, amide-amide interactions (as N - H⋯O=C) results in distinct chains of A and B molecules running parallel to the a-axis direction. C - H⋯O interactions also occur. Source

Shah M.,Quaid-i-Azam University | Ali S.,Quaid-i-Azam University | Tariq M.,Quaid-i-Azam University | Khalid N.,Pakistan Institute of Nuclear Science and Technology | And 2 more authors.

The transesterification of jojoba oil with methanol has been studied in the presence of various catalysts i.e., sodium hydroxide (NaOH), potassium hydroxide (KOH), dibutyltin diacetate (C4H9)2Sn (OOCCH3)2, dioctyltin diacetate (C8H 17)2Sn (OOCCH3)2, dibutyltin oxide (C4H9)2SnO, dioctyltin oxide (C 8H17)2SnO, diphenyltin oxide (C 6H5)2SnO, monobutyltin chloride dihydroxide ((C4H9)Sn(OH)2Cl) and monobutyltin hydroxide oxide hydrate ((C4H9)Sn(=O)OH×xH2O), with % age conversion of oil into biodiesel was 84.5%, 61.3%, 92.6%, 25.4%, 22.0%, 23.3%, 12.0%, 2.15% and 1.05%, respectively. The optimization of experimental parameters was established to achieve maximum yield of the product by using dibutyltin diacetate (C4H9)2Sn (OOCCH 3)2. The physical and fuel properties of jojoba biodiesel like density, dynamic viscosity, kinematic viscosity, pour point, cloud point, flash point, and acid number were determined by ASTM procedures and were found to be comparable to ASTM standards for diesels. The synthesis of jojoba seed oil biodiesel (JSOB) was confirmed by FT-IR and NMR (1H and 13C) analyses of both oil and biodiesel. Chemical composition of fatty acid methyl esters (FAMEs) in jojoba biodiesel was established by GC-MS analysis and verified by retention time data and mass fragmentation pattern. © 2013 Elsevier Ltd. All rights reserved. Source

Ahmed M.,NESCOM | Badshah S.,International Islamic University, Islamabad | Khan R.U.,International Islamic University, Islamabad | sajjad M.,International Islamic University, Islamabad | Jan S.,International Islamic University, Islamabad
International Journal of Engineering and Technology

This paper illustrates the theory behind computational fluid dynamics (CFD) of flow though a gas turbine engine low pressure compressor. The goal of study is to develop a tool to perform shape optimization of low speed airfoils. Mathematical model and computational tool are developed using programming software. Analytical solution is developed to create airfoil geometry. The NACA 4 digits library is used with design parameters that control camber and the thickness of the airfoil. Solver is capable of providing derivatives of the objective function and limiting constraints with the solution for each set of parameters. Source

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