Showing papers by "Spiros V. Paras published in 2015"
TL;DR: In this article, the authors investigate how the addition of an organic surface active agent affects the characteristics of a bubble column equipped with a porous sparger and containing a non-Newtonian liquid, showing that the diameter of the bubbles decreases and the transition point from the homogeneous to the heterogeneous is shifted to higher gas flow rates, when the surfactant is added.
Abstract: The purpose of this work is to investigate how the addition of an organic surface active agent affects the characteristics of a bubble column equipped with a porous sparger and containing a non-Newtonian liquid. Water and an aqueous glycerin solution, both containing a minute amount of xanthan gum, were the non-Newtonian shear thinning liquids, while the gas phase was atmospheric air for all cases. Small amounts of the non-ionic surface active agent Triton X-100 was added to modify the surface tension of the non-Newtonian solutions. The results show that the diameter of the bubbles decreases and the transition point from the homogeneous to the heterogeneous is shifted to higher gas flow rates, when the surfactant is added. Appropriate correlations are also proposed, which take into account the liquid phase properties, the gas phase flow rate, as well as the column and sparger characteristics and predict with reasonable accuracy the transition point from the homogenous to the heterogeneous regime, the Sauter mean diameter of the bubbles and the average gas holdup.
48 citations
TL;DR: In this article, a miniature plate heat exchanger with modulated surface along with nanofluids used as working liquids is proposed aiming for a more compact and efficient cooling equipment for low-temperature applications.
30 citations
TL;DR: The present protocol study proposes a simple algorithm that, given the type of molecules of the therapeutic agent and the maximum acceptable time for the drug concentration to attain a required value at the pulpal side of the tubules, can estimate the initial concentration to be imposed.
Abstract: The need for simulation models to thoroughly test the inflammatory effects of dental materials and dentinogenic effects of specific signaling molecules has been well recognized in current dental research. The development of a model that simulates the transdentinal flow and the mass transfer mechanisms is of prime importance in terms of achieving the objectives of developing more effective treatment modalities in restorative dentistry. The present protocol study is part of an ongoing investigation on the development of a methodology that can calculate the transport rate of selected molecules inside a typical dentinal tubule. The transport rate of biological molecules has been investigated using a validated CFD code. In that framework we propose a simple algorithm that, given the type of molecules of the therapeutic agent and the maximum acceptable time for the drug concentration to attain a required value at the pulpal side of the tubules, can estimate the initial concentration to be imposed.
3 citations