This book includes studies that give mathematical solution methods and mathematical modeling to support these methods for solving problems in the current application area of engineering, as well as studies that include solutions for problems that are also related to current life areas. In this book, some current problems in the field of mathematics and engineering, solutions to solve these problems and existing engineering methods for these problems are included. Basically, machinery, chemistry, electronics, computers, construction, environment, etc. studies in both the application and theoretical fields of mathematics are needed to solve optimization, modeling, encryption methods and thermal problems that are currently encountered in engineering fields. In this book, some current problems are presented and related theoretical and applied mathematical studies are included.