Papers by Keyword: Nanotechnologies

Abstract: This article deals with the selection of a suitable gelling agent for refractory castable with a sol-gel binder system. The goal is to find the optimal ratio between gelation time, content, and concentration of the solution. Various salts (NaCl, NH₄Cl, Ca(NO₃)₂) are investigated as gelling agents. Gelation curves are constructed from gelation time observations. For the design of the formula of refractory castable with a sol-gel bond, it is important to know the behavior of the sol after mixing with the gelling agent. This is the goal of the experiment. In the end, we will obtain initial data for further proposals for the composition of refractory castable with a sol-gel bond.

Abstract: Nanosciences and nanotechnology (NST) constitute currently a major research field all over the world. NST deal with the study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales, where properties differ significantly from those at the larger scale. The properties of materials can be different at the nanoscale for two main reasons : size and quantum effects. Effects negligible at the macroscopic level become important at the nanometer scale, and vice versa. Scaling laws are described in order to understand some differences. Moreover, geometric arguments are necessary to understand the origin of some physical and chemical properties of nanosystems. On the other hand, quantum effects can begin to dominate the behaviour of matter at the nanoscale – particularly at the lower end – affecting the optical, electrical and magnetic behaviour of materials. The characteristic dimensions for which the properties change from the “macro-“ to the “nano-“ regimes are discussed.