The present book is organized in seven chapters and two appendices. Each one of the chapters 2 to 6 consists of an introduction containing the necessary literature review of the corresponding problem, the statement of the problem, the numerical solution, a number of representative numerical examples and finally the concluding remarks. Chapter 1 refers to the motivation, the objectives and the novelties of the study. In the final chapter (7), the main conclusions are summarized, while suggestions and goals for future research are proposed.