density

In order to compute level of service and density in weaving segments, the Highway Capacity Manual (HCM) defined for the first time in 2010 a relationship based on a lane change rate to assess the density of the weaving segment. It is critical to accurately estimate lane changing rate in these situations, but field observations in weaving segments shorter than 250 meters in Tehran, Iran revealed a significant difference between the HCM2016 model estimate and field data. The traffic and geometric data collected at 87 (15-minute) intervals from six weaving segments in Tehran were used to develop models for estimating lane changing rate in weaving segments. These 87 intervals were then divided into 69 (terrain data) for equations and 18 (test data) for model comparisons. Weaving volume and weaving segment area are introduced as two independent variables in the optional lane changing rate model of weaving vehicles in this study, with R2=0.74. Furthermore, for a lane-changing model of non-weaving vehicles with R2=0.95, two new variables of non-weaving volume and traffic solidity were defined. Finally, based on the 18 intervals used to test the results, it showed the improvement of the developed models results compared to HCM2016 models.

Ionic Liquid(IL)now refers to fluids that are liquid at temperatures above 100°C, they are called "Green"solvents.One of their applications is in heat transfer and solar collectors.Thermophysical properties can be improved by adding nanoparticles to the IL.For this reason,spherical and rod-shaped alumina nanoparticles were added to 1-Hexyl-3-methyl imidazolium hexafluorophosphate IL with different weight percentages. The effect of adding nanoparticles on thermophysical properties of IL such as density,viscosity,thermal conductivity, and heat capacity in 0.05,0.1 and 0.5 %wt of nanoparticles at temperatures of 20, 30, and 50 °C is investigated. Increasing the concentration of nanoparticle set out an increase in density, viscosity, and thermal conductivity and a decrease in the thermal capacity of the ionic nanofluid (INF) compared to the base IL.Also, the viscosity, density, and thermal conductivity in INF with rod-shaped alumina nanoparticles are improved more than spherical alumina nanoparticles. Also the experimental viscosity and thermal conductivity data were fitted with the existing theoretical models. the viscosity of spherical alumina-IL and rod-shape alumina-IL was in unison with particles aggregation effect (Krieger-Dougherty model) and the both INF effective thermal conductivity are prognosticated by interfacial layer approach with sufficient accuracy.Eventually nonlinear equations have also been proposed for changes in the thermophysical properties of viscosity.

The use of ferrofluids as shapeable external appendage to a submerged body and as a mean of vortex flow induction is studied in this paper. Ansys-CFX numerical results are validated against analytical problems and used to analyze the ferrofluid free surface shape affected by gravity, different magnets and different densities of the surrounding non-magnetic fluids. It is demonstrated that the height, width, and curvature of ferrofluid can be controlled by magnet size and strength. It is also observed that ferrofluid mass loss may occur due to gravity which should be addressed in designing a fluid appendage. Subsequently, vortex production inside the ferrofluid is investigated via a shear flow on the magnet. It is shown that ferrofluid can contain complex vortices while being shaped by the magnetic field, gravity, and the vortices. It is also observed that vortices inside the ferrofluid affect the flow of the surrounding fluid. Additionally, the effects of surface tension and viscosity are briefly analyzed to roughly show the importance of these parameters for further works. Overall, it is concluded that using ferrofluids as appendages for shaping and controlling fluid flow around submerged bodies seem to be practical and needs further attention.