in this study, a generalized equation is presented to calculate vapor pressure of pure substances as a function of reduced temperature, critical pressure, and acentric factor. with the presented model, vapor pressures have been calculated and evaluated with nist data bank for 70 pure substances for about 14000 data points, and the overall average absolute percentage deviation has been only 0.78...

in the course of this study, empirical models were developed for the pressure-density relationship in a large cubic baler for baling alfalfa and barley straw. least squares regression analysis was employed to develop the empirical model and estimate the model coefficients by minimizing the summation of the squared differences between data resulting from the developed empirical model and the cor...

abstract: compaction under tractors tires is of special concern because the weight of these machines has increased dramatically in the last years. these machines and others associated with crop cultural practices weight enough to significantly compact the soil, especially if the soil is soft with high moisture content during tilling, planting, or harvesting. the stress distribution and the size...

the variations in plastic injection molding process may lead to the inconsistency of molded parts' dimensions. furthermore, due to the speed of production as well as post-shrinkage of molded parts make the control of process difficult and give inaccurate molded parts. the objective of this research is to predict the dimensions of injection molded parts on the basis of cavity pressure durin...

background and objective: the circle of willis (cow) supports adequate blood supply to the brain. the cardiovascular system, in the current study, is modeled using an equivalent electronic system focusing on the cow. method: in our previous study we used 42 compartments to model whole car- diovascular system. in the current study, nevertheless, we extended our model by using 63 compartments to ...

Bend existence induces changes in the flow pattern, velocity profiles and water surface. In the present study, based on experimental data, first three-dimensional computational fluid dynamic (CFD) model is simulated by using Fluent two-phase (water + air) as the free surface and the volume of fluid method, to predict the two significant variables (velocity and channel bed pressure) in 90º sharp...

introduction nowadays, due to higher environmental pollution and decreasing fossil fuels many countries make decisions to use renewable fuels and restrict using of fossil fuels. renewable fuels generally produce from biological sources. biodiesel is an alternative diesel fuel derived from the transesterification of vegetable oils, animal fats, or waste frying oils. considering the differences be...

In this work we have used a closed system model to derive an analytical equation for the osmotic pressure of two component electrolyte and non-electrolyte solutions. In order to do so, we have used an equation of state, known as the dense system equation of state (DSEOS), for the model system. Based on the model, a new definition is given for the osmotic pressure of a closed system. Good ag...

Although two-phase flow is frequently encountered in various location of the process plants, there is no a general accepted and verified two-phase flow model that may be used to size lines for such conditions. An obvious example is condensate water return lines. The API method that used in this study is based on the homogeneous equilibrium flow assumption, that is, equal velocity and equal temp...