This paper demonstrates the applications of artificial neural networks to predict the equivalent continuous sound level (L Aeq ) and 10 Percentile exceeded sound level (L 10 ) generated due to traffic noise for various locations in Delhi. A Model based on back-propagation neural network was trained, validated, and tested using the measured data. The work shows that the model is able to produce accurate predictions of hourly traffic noise levels. A comparative study shows that neural networks out-perform the multiple linear regression models developed in terms of total traffic flow and equivalent traffic flow. The prediction model proposed in the study may serve as a vital tool for traffic noise forecasting and noise abatement measures to be undertaken for Delhi city.
A mathematical model is developed to analyse the effect of polymer additives on thermal elastohydrodynamic lubrication (EHL) behaviour under heavily-loaded rolling/sliding line contacts. The lubricant is assumed to be couple stress fluid and a non-dimensional couple stress parameter represents the molecular length of the additives. The Reynolds and mean temperature equations for the couple stress fluid (CSF) are derived using the rheological relationship presented by Stokes. The thermal EHL characteristics computed for polymer modified oils are found to have a strong dependence on the couple stress parameter. Polymer additives are shown to cause a significant increase in fluid-film thickness along with a noteworthy reduction in the coefficient of friction without any rise in fluid pressure. In addition, the polymer additives are found to cause a minimization of the thermal reduction in the fluid-film thickness as a well as decrease in fluid temperature, particularly under low speed-high load conditions, where fluid films are quite thin. These improvements are desirable in situations involving continuously varying slide to roll ratios, e.g. in gears.
A complete numerical solution to the transient elastohydrodynamic lubrication (EHL) problem of an involute spur gear is obtained under isothermal condition. The lubricant is assumed to be couple-stress fluid and the transient Reynolds equation for the compressible couple-stress fluid is derived using Stokes theory. The EHL characteristics computed for couple-stress fluids are found to have strong dependence on couple-stress parameter. Significant increase in minimum film thickness due to couple-stress fluid is observed. Also, it is found that couple-stress fluids tend to smoothen the variation of film thickness along the line of action caused by transient effects.
The effect of couple stress fluids on elastohydrodynamic lubrication (EHL) behaviour in smooth as well as rough line contacts is investigated numerically at low speed-high load and high speed-low load conditions. A non-dimensional couple stress parameter represents the molecular length of the additives. The EHL characteristics computed for couple stress fluids are found to have strong dependence on couple stress parameter. Significant increase in minimum film thickness due to couple stress fluid is observed. Also, the surface roughness effects on EHL behaviour are influenced by couple stress fluid to an extent depending upon the speed-load conditions.
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