A kinetic model of a fixed bed tubular reactor incorporating catalyst deactivation was developed for the ISOMAX unit of Arak refinery. The kinetic parameters for the hydrocracking reactions over the commercial catalyst were determined using initial activity plant data i.e. when the catalyst is fresh. Catalyst deactivation was then taken into account by means of deactivation function based on pl...

This paper presents a detailed model of a novel electropneumatic valve actuator for both engine intake and exhaust valves. The valve actuator’s main function is to provide variable valve timing and variable lift capabilities in an internal combustion engine. The pneumatic actuation is used to open the valve and the hydraulic latch mechanism is used to hold the valve open and to reduce valve sea...

A computational study of a directinjection (DI) engine intake system using KIVA-3V was conducted. The engine considered had two intake ports designed to generate a swirling motion of the intake charge in the cylinder. To investigate the effect of adding shrouds to the intake valves on swirl, two sets of intake valves were considered; the first set consisted of conventional valves, and the secon...

Water deprivation-induced thirst is explained by the double-depletion hypothesis, which predicts that dehydration of the two major body fluid compartments, the extracellular and intracellular compartments, activates signals that combine centrally to induce water intake. However, sodium appetite is also elicited by water deprivation. In this brief review, we stress the importance of the water-de...

ABSTRACT Stringent NOx and particulate emission constraints require high levels of exhaust gas recirculation. In this paper we model and analyze a Variable Valve Timing methodology that in steady-state achieves large levels of internal Exhaust Gas Recirculation (iEGR) or residual charge in Compression Ignition Direct Injection (CIDI) engines. Current external Exhaust Gas Recirculation (eEGR) te...

In this study, a quasi-realistic thermodynamic analysis was performed to investigate the effects of design and operating parameters on performance single-cylinder modern Atkinson cycle engine. Fortran used for all calculations. It assumed that fuel-air mixture as working fluid, iso-octane fuel. The Wiebe function combustion process it specific heat fluid varies with temperature. calculations, t...

Accelerated deactivation of Co/Al2O3 catalysts in Fischer-Tropsch synthesis and the effect of Re and Ru as the catalytic promoters are reported. 15wt% Co/Al2O3 catalyst and 1wt% Ru and 1.4wt% Re  promoted cobalt catalysts have been formulated and extensively characterized. The deactivation of the unpromoted cobalt catalyst and those promoted with ...

In this paper some results concerning the effect of intake flow modeling obtained by 3D numerical modeling of combustion on flame front shape and its displacement through combustion chamber geometry of s.i .engine consisting of flat head with two ver tical valves and cylindrical bowl were presented. These results obtained with KIVA3V code were compared with results of flame front shape and its ...