**Meet the editor**

Professor Héctor Pérez-de-Tejada obtained a bachelor's degree in science from the National Autonomous University of Mexico (UNAM) and later received his PhD degree from the University of Colorado (Boulder, Colorado). He has been a full researcher at the Institute of Geophysics of UNAM and participated in various academic functions first at the Ensenada (Baja Califor-

nia) campus and later at the Mexico City campus of that Institution. He was president of the Mexican Geophysical Union and has been a fellow of the National Research System in Mexico (level 3). Currently, he is the head of the Space Science Department of the Institute of Geophysics of UNAM, has participated in numerous research projects including as a guest investigator of the Pioneer Venus Orbiter mission of NASA at Venus, and has been involved in the analysis of plasma data of the Mars and Venus Express spacecraft of ESA. His academic activities have been related to studies of the interaction of the solar wind with planetary ionospheres and he has participated in many scientific publications where he has been the main author in most of them. He has been responsible for activities in the ionospheric sounder station near Mexico City and has been the supervisor of many graduate students at the Ensenada and at the Mexico City campuses of UNAM.

## Contents

## **Preface XI**


Omar D. Lopez, Sergio Pedraza and Jose R. Toro


Chapter 13 **Vortex Spinning System and Vortex Yarn Structure 247** Gizem Karakan Günaydin and Ali Serkan Soydan
