Significance Of Viscosity Research Articles

Optimization of viscosity of titania nanotubes ethylene glycol/water-based nanofluids using response surface methodology

Nanofluids have gained significant importance in heat transfer applications due to their unique thermal properties, such as higher thermal conductivity, higher convective heat transfer coefficients, and improved thermal stability. They offer the potential for more efficient heat transfer in various engineering applications, including cooling systems, heat exchangers, and thermal energy storage systems. Additionally, their use can lead to reduced energy consumption and improved performance in various industrial processes, making them an attractive option for researchers and engineers in heat transfer. Their thermophysical properties must be known to gain the maximum benefits of using nanofluids as process fluids. Despite the significance of viscosity as a characteristic of nanofluids, adequate research on viscosity modeling cannot offer accurate predictions. The current work aims to use Response Surface Methodology to develop a prediction model for the viscosity of a nanofluid comprised of Titanium (TiO2) nanotubes dissolved in ethylene glycol and water. Different mass concentrations of nanotubes ranged from 0% to 1%, the shear rate was set to 150–500 s−1, and the temperature range was kept from 25 to 65 °C. Moreover, a comprehensive optimization study was conducted using the proposed model. The significance of process input parameters was assessed, and the findings showed that the nanofluid concentration is the most significant input, followed by temperature and shear rate. Two case studies were explored for both maximization and minimization of viscosity. The optimization results showed that the optimum condition, for viscosity maximization (0.00371 Pa·s), of input parameters such as nanofluid concentration, temperature, and shear rate are 0.675%, 205 1/s, and 25 °C for the maximum viscosity 0.00371 Pa·s. For viscosity minimization, the optimum input parameters were nanofluid concentration, temperature, and shear rate are 0.04%, 179 1/s, and 63.4 °C, respectively.

Significance of viscosity and thermal conductivity variation parameters on the dynamics of Newtonian fluid conveying tiny particles over a convectively heated surface

The significance of viscosity and thermal conductivity variation parameters on the dynamics of Newtonian fluid conveying tiny particles over a convectively heated surface is examined. The dimensional partial differential equations controlling the flow are remodeled to ordinary differential equations via suitable similarity variables in conjunction with the rescaled Nusselt, Sherwood and density number of motile microorganisms. The resulting nonlinear coupled ordinary differential equations are consequently scaled down to a system of first order ordinary differential equations. The system of equations are evaluated arithmetically via shooting technique along with fourth order Runge–Kutta integration scheme for different boundary conditions. The result was found to be in excellent agreement when compared with available records in the literature. The major highlights of the problem are analyzed and discussed thoroughly. It is seen that increase in viscosity variation parameter is capable to cause a decline in the local skin friction coefficients at the rate of − 0 . 04985 and the Nusselt number is an increasing function of the thermal conductivity variation parameter.

INVESTING IN THE COMMONS: A STUDY OF OPENNESS AND THE EMERGENCE OF COOPERATION

This paper examines the evolution of agent strategies in a commons dilemma using a tag interaction model. Using a tag-mediated interaction model, individual's can determine their interactions based on their tag similarity. The experimental results show the significance of agent strategies that contribute to the overall value of the commons. The paper also examines the significance of viscosity on the emergence of cooperation in the commons dilemma. Viscosity represents a specific form of openness that will be examined in the paper. An initial series of experiments demonstrates the role of tags in the n-player dilemma while subsequent experiments examine the impact of openness on the evolution of agent strategies. The paper shows the emergence of cooperation through tag-mediated interactions. Simulation results show the emergence of strategies that contribute heavily to the value of the shared commons. The role of viscosity on the population strategy set is examined and this is similar to some forms of openness in multi-agent environments.

The significance of viscosity in density-dependent flow of groundwater

Abstract Many modeling studies of variable-density groundwater flow have been performed in the last few decades. In most of these studies, fluid density is considered to vary with concentration, while the variation of viscosity with concentration is neglected. The consequences of this negligence is not completely known. The present study uses a numerical simulation approach to investigate the density-viscosity-concentration relationship during groundwater flow and solute transport through a density-stratified system. Fluid density is assumed to increase with depth from freshwater at the surface, through brackish and saline waters, to brines at the bottom half of the system. The system mimics field observations at the Atikokan Research Area (ARA) in northwestern Ontario, Canada. Hypothetical ‘unit basin’ models, consisting of recharge-, midline- and discharge-area regimes are employed. Simulations with the density-concentration equation of state and a constant (freshwater) viscosity in the density-stratified system causes groundwater to sink against the buoyancy forces of the system. More water is recharged into the system than necessitated by the buoyancy. The configurations and lengths of travel paths, and travel time of conservative contaminants are inaccurately predicted. Accounting for concentration in the viscosity equation causes groundwater floating in agreement with the expected buoyancy physics of the system. Overestimation of concentration-dependent density causes sinking, whereas, overestimation of viscosity results in overfloating and underestimation of groundwater recharge. Even in density-stratified fluids with salinity of seawater, recharge and through flow of water may be slightly overestimated if a concentration-dependent depsity is used along with a constant freshwater viscosity. The concentration dependence of both density and viscosity are to be analyzed carefully during groundwater flow and solute transport simulations in systems with considerable fluid density variations.

Viscosity of Dental Porcelain as a Function of Temperature

A method for viscosity measurement is described and representative data are given for opaque, gingival, and incisal porcelains. The significance of viscosity in annealing and in stress development due to thermal expansion mismatch is discussed. Thermal history of the porcelain is shown to be important only over a relatively small temperature interval in affecting residual stresses.