The veri cation of timed systems is extremely important but also extremely di cult Several methods have been proposed to assist in this task including extensions to symbolic model checking One possible use of model checking to analyze timed systems is by modeling passage of time as the number of taken transitions and ap plying quantitative algorithms to determine the timing parameters of the sy...

The proton exchange membrane (PEM) fuel cell is being investigated as an alternate power source for various applications like transportation and emergency power supplies. The paper presents a novel circuit model for a PEM fuel cell that can be used to design and analyze fuel cell power systems. The PSPICE-based model uses bipolar junction transistors (BJTs) and LC elements available in the PSPI...

The MCNP5 Monte Carlo code has been frequently used to model HTGRs with explicit geometric representation of fuel compacts or pebbles, including the microscopic fuel kernels within them. The random locations of fuel kernels within each fuel compact or pebble, and of pebbles within the core, however, present difficulties. A new, on-the-fly, stochastic geometry model for MCNP5 has been developed ...

This study studies the relationship between tyre pressure and fuel consumption of vehicles using experimental methods and mathematical model to predict vehicle fuel consumption. The model obtained was F = 0.62722.5941p+3.3428p±0.018 where F is the fuel consumed and p is the tyre pressure of a vehicle, which can also be used to predict the amount of fuel consumed by other vehicles. The model was...

A model for heat-recirculating micro combustor is developed. It investigates the structure of laminar, one-dimensional and steady state flame propagation in uniformly premixed wood particles with considering the effects of heat recirculation caused by configuration of micro combustor. The flame structure is divided into three regions: a preheat-devolatilization zone where the rate of the gas-ph...

The present Computational Fluid Dynamics (CFD) work deals with the modeling of complete coal direct chemical looping sub-pilot unit which use coal as fuel and ferric oxide supported on alumina as an oxygen carrier. The 2D CFD model of the complete arrangement incorporating both fuel and air reactors and their inter-connecting parts was solved using FLUENT. The CFD model wa...

A spatially explicit forest gap model was developed for the Sierra Nevada, California, and is the first of its kind because it integrates climate, fire and forest pattern. The model simulates a forest stand as a grid of 15×15 m forest plots and simulates the growth of individual trees within each plot. Fuel inputs are generated from each individual tree according to tree size and species. Fuel ...

Computational fluid dynamics analysis was employed to investigate the radial flow field patterns of proton exchange membrane fuel cells (PEMFC) with different channel geometries at high operating current densities. 3D, non-isothermal was used with single straight channel geometry. Our study showed that new generation of fuel cells with circle stack with the same active area and inlet area gave ...

This paper considers modeling and simulation study of a fuel cell system. A mathematical model of a Polymer Electrolyte Membrane (PEM) Fuel Cell system is presented in this paper. For the convenience of presentation, cathode flow, anode flow, the membrane hydration, and voltage output expressions of the PEM fuel cell system are given in the paper to bridge a generic model to the model of Fuel C...