In the pantheon of air power spokesmen, Giulio Douhet holds center stage. His writings, more often cited than perhaps actually read, appear as excerpts and aphorisms in the writings of numerous other air power spokesmen, advocates-and critics. Though a highly controversial figure, the very controversy that surrounds him offers to us a testimonial of the value and depth of his work, and the need for airmen today to become familiar with his thought. The progressive development of air power to the point where, today, it is more correct to refer to aerospace power has not outdated the notions of Douhet in the slightest In fact, in many ways, the kinds of technological capabilities that we enjoy as a global air power provider attest to the breadth of his vision. Douhet, together with Hugh “Boom” Trenchard of Great Britain and William “Billy” Mitchell of the United States, is justly recognized as one of the three great spokesmen of the early air power era. This reprint is offered in the spirit of continuing the dialogue that Douhet himself so perceptively began with the first edition of this book, published in 1921. Readers may well find much that they disagree with in this book, but also much that is of enduring value. The vital necessity of Douhet’s central vision-that command of the air is all important in modern warfare-has been proven throughout the history of wars in this century, from the fighting over the Somme to the air war over Kuwait and Iraq.

Throughout most of the twentieth century, electric propulsion was considered the technology of the future. Now, the future has arrived. This important new book explains the fundamentals of electric propulsion for spacecraft and describes in detail the physics and characteristics of the two major electric thrusters in use today, ion and Hall thrusters. The authors provide an introduction to plasma physics in order to allow readers to understand the models and derivations used in determining electric thruster performance. They then go on to present detailed explanations of: Thruster principles Ion thruster plasma generators and accelerator grids Hollow cathodes Hall thrusters Ion and Hall thruster plumes Flight ion and Hall thrusters Based largely on research and development performed at the Jet Propulsion Laboratory (JPL) and complemented with scores of tables, figures, homework problems, and references, Fundamentals of Electric Propulsion: Ion and Hall Thrusters is an indispensable textbook for advanced undergraduate and graduate students who are preparing to enter the aerospace industry. It also serves as an equally valuable resource for professional engineers already at work in the field.

A compilation of 3M voices, memories, facts and experiences from the company's first 100 years.

The Global Innovation Index ranks the innovation performance of 143 countries and economies around the world, based on 81 indicators. This edition explores the role of the individuals and teams behind the innovation process. It sheds light on different aspects of human capital required to achieve innovation, including skilled labor; the intersection of human, financial and technological capital; talent retention; and the mobilization of highly educated people.

The Global Innovation Index ranks the innovation performance of 141 countries and economies around the world, based on 79 indicators. This edition explores the impact of innovation-oriented policies on economic growth and development. High-income and developing countries alike are seeking innovation-driven growth through different strategies. Some countries are successfully improving their innovation capacity, while others still struggle.

The Global Innovation Index 2020 provides detailed metrics about the innovation performance of 131 countries and economies around the world. Its 80 indicators explore a broad vision of innovation, including political environment, education, infrastructure and business sophistication. The 2020 edition sheds light on the state of innovation financing by investigating the evolution of financing mechanisms for entrepreneurs and other innovators, and by pointing to progress and remaining challenges – including in the context of the economic slowdown induced by the coronavirus disease (COVID-19) crisis.