the sources of groundwater pollution such as, industrial effluents, sewage and extensive farming have lead to agrochemical pollution. mathematical modeling helps to analyze the existing situation, allows forecasting, and to evaluate the effects of changes in the surrounding water quality. the present research has been focused mainly towards understanding the various processes affecting the tran...

in this paper energy bands and berry curvature of graphene was studied. desired hamiltonian regarding the next-nearest neighbors obtained by tight binding model. by using the second quantization approach, the transformation matrix is calculated and the hamiltonian of system is diagonalized. with this hamiltonian, the band structure and wave function can be calculated. by using calculated wave f...

This paper reports a modelling work on the existing experimental data of single coal particles combustion process [1,2]. Two kinds of coal particles (a high-volatile bituminous coal / a lignite coal) are injected in a drop-tube furnace, ignited and burned in quiescent O2/N2 and O2/CO2 atmospheres with oxygen mole fraction varying from 20% to 100%. Ignition delay time, particle life time and par...

Diesel engine emission standards are being more stringent as it gains more publicity in industry and transportation. Hence, designers have to suggest new controlling strategies which result in small amounts of emissions and a reasonable fuel economy. To achieve such a target, multi-objective optimization methodology is a good approach inasmuch as several types of objective are minimized or maxi...

The spark advance determines the efficiency of spark-ignited (SI) engines by positioning the combustion in relation to the piston motion. Today’s spark-advance controllers are open-loop systems that measure parameters that effect the sparkadvance setting and compensate for their effects. Several parameters influence the best spark-advance setting but it would be too expensive to measure and acc...

One strategy to decrease the amount of oxides of nitrogen formed and emitted from certain combustion devices, such as the internal combustion engine, is to recirculate and introduce a portion of the unburned product gases with the air and fuel. The effect of the re-circulated gases is to decrease the maximum temperatures in the flame zone, and hence decrease NOx formation. However, dilution of ...

The effect of inlet swirl on the flow development and combustion dynamics in a lean-premixed swirl-stabilized combustor has been numerically investigated using a large-eddy-simulation (LES) technique along with a level-set flamelet library approach. Results indicate that when the inlet swirl number exceeds a critical value, a vortex-breakdown-induced central toroidal recirculation zone is estab...

Elemental characterization of fine particulate matter was undertaken at schools and residences in three low income neighborhoods in Quito, Ecuador. The three zones were located in the northern (Cotocollao), south central (El Camal), and south east (Los Chillos) neighborhoods and were classified as zones 1-3, respectively. Forty elements were quantified via ICP-MS analysis. Amongst the geogenic ...

This paper describes the modifications and evolution of a thermal pulse combustionmodel for predicting the combustion oscillations of an aerovalved 250 kW pulse combustorincorporating a soot formation-combustion model. Validation of the model is carried out from theexperimental data of an aerovalved Helmholtz type pulse combustor, where a sinusoidal air inlet massflow coupled with pressure osci...

The Homogeneous Charge Compression Ignition (HCCI) combustion concept lacks direct ignition timing control, instead the auto ignition depends on the operating condition. Since auto ignition of a homogeneous mixture is very sensitive to operating conditions, a fast combustion timing control is necessary for reliable operation. Hence, feedback is needed and the crank angle of 50% burnt (CA50) has...