Mine tailings are waste materials that resulted from the extraction and processing of raw materials to form mineral products. These dusty particles present negative environmental effects after being deposited in different types of dumping areas. Based on the circular economy concepts and the presently pushing need of identifying wastes as a potential replacement for natural resources, this chapter aims to present the physical (density, microstructure) and mechanical (compressive strength, flexural strength) characteristics of different types of geopolymers which use mine tailings as precursors or blended systems (mixes of different raw materials). The main reasons of approaching this topic are the need to decrease the consumption of natural resources, reduce environmental pollution and create an economic system aimed to capitalize the mining wastes. Accordingly, this chapter includes information regarding the availability of this waste and its potential utilization as a raw material in civil engineering applications. Therefore, reports of specific agencies and multiple research studies which approach tailing based geopolymers or blended systems have been summarized.
Part of the book: Advances in Geopolymer-Zeolite Composites
Bioactive glasses are very attractive materials, used for tissue engineering materials, usually to fill and restore bone defects. This category of biomaterials, show considerable potential for orthopaedic surgery because they can promote bone tissue regeneration. Many trace elements have been incorporated in the glass network, an example is metallic glasses to obtain the desired properties. Because of tolerable mechanical properties, and because they are able to bond to living bone and stimulate its regeneration, this bioactive glasses have a particular interest and are in a continuous research and improvement. The chapter presents the history of bioactive glasses, classification, include a summary of common fabrication methods, applications, surface coatings, applications and future trends in relation to human bone. This review highlight new trends and areas of future research for bioactive glasses.
Part of the book: Current Concepts in Dental Implantology
The solar furnace works by using the electric energy produced by a photovoltaic system, which converts solar energy, solar radiation, into electric energy. The performances of the solar furnace used in various applications from industry are influenced by various factors. One of these factors imposes the acquisitions of certain large densities of the radiant power, and it requires a geometric form of the concentrator. The research is based on the behavior of some metallic alloys at elevated temperatures, for purifying some materials and for the achievement of some chemical synthesis. An important technological condition is a temperature which is achieved by concentrating solar radiation. This temperature is necessary to produce metallic material in the crucible, without other complementary energy for the thermal process. Steel or aluminum production requires very high quantities of thermal energy. Usually, this energy is given by electric power, natural gases, or conventional fuels. The solar furnace uses the energy given by the sun. For the manufacturing of the electrothermal furnaces, a series of specific materials are used, which are necessary for the obtaining of the furnace chamber, for the heating elements, as well as for the measurement systems of the temperature.
Part of the book: Latest Research on Energy Recovery