Nadi̇r Toprak Elementleri̇ni̇n Uygulama Alanlari

Abstract

Mines have always had an indispensable importance in the history of humankind. Historically, a direct relationship can be established between mining activities and the level of development and thus the level of well-being in societies. Rare earth minerals are one of the strategically known raw materials in the world. Following enrichment and purification processes, it is identified by different names such as rare earth elements (REEs), rare earth metals (REMs) and rare earth oxides (REOs). The discovery of REEs and its technological developments have an impact on almost all aspects of our lives. Rare earth materials have unique physical and chemical properties. REEs are used as components in high-tech applications including magnets, catalysts, metal alloys, electronic devices, lasers, glass-ceramics, rechargeable batteries, medical imaging, telecommunications, lighting, and new generation semiconductor devices. In addition, some important REEs elements such as samarium (Sm), neodymium (Nd), dysprosium (Dy), praseodymium (Pr) and erbium (Er) are used in the defense industry and renewable energy technologies (wind and solar energy). The demand for this raw materials used in the critical technologies will largely increase in the future. In this article, the important applications, usage areas and critical importances of rare earth elements have been extensively discussed.

Bleaching of Woven Terry Cotton Fabrics with Ozone Gas

“…Prabaharan ve Rao (2001) yaptıkları çalışmada pamuklu kumaşı 100 g/m 3 ozon konsantrasyonunda 5 dk süre ile farklı pH değerlerinde (2,4,6,8,10,12) ozonlamışlardır. Elde edilen sonuçlara göre pH arttıkça kumaşların beyazlık derecelerinde düşme olduğu gözlemlenmiştir.…”