Variations in the shape of the fission-product mass yield distribution curve when U/sup 235/ is irradiated with neutrons of various energies up to 0.5 ev were studied by radiochemical measurements of peak-to-valley ratios. A> 30 increase in the relative amount of symmetric fission was found at the peak of the 0.29 ev resonance compared to the amount of symmetric fission produced with thermal neutrons. A decrease in the amount of symmetric fission was observed at increasing neutron energies where symmetric fission was 18% less common with epi-cadmium pile neutrons than with those at thermal energy. At neutron energies below 0.01 ev a sudden increase in the relative amount of symmetric fission was also found, even though there is no evidence from cross-section data for a resonance in this energy region. The results of this study are compared with those of other investigations at higher neutron energies. A discussion is presented regarding implications of mass-yield variations in the theory of fission through saddle-point states. (auth).

Hydrogen and fuel cells are vital technologies to ensure a secure and CO2-free energy future. Their development will take decades of extensive public and private effort to achieve technology breakthroughs and commercial maturity. Government research programs are indispensable for catalyzing the development process. This report maps the IEA countries' current efforts to research, develop and deploy the interlocking elements that constitute a "hydrogen economy", including CO2 capture and storage when hydrogen is produced out of fossil fuels. It provides an overview of what is being done, and by whom, covering an extensive complexity of national government R & D programs. The survey highlights the potential for exploiting the benefits of the international cooperation. This book draws primarily upon information contributed by IEA governments. In virtually all the IEA countries, important R & D and policy efforts on hydrogen and fuel cells are in place and expanding. Some are fully-integrated, government-funded programs, some are a key element in an overall strategy spread among multiple public and private efforts. The large amount of information provided in this publication reflects the vast array of technologies and logistics required to build the "hydrogen economy."--Publisher description.

This book is a collection of all pertinent information on radiation safety applicable in nuclear medicine and research using radioactive materials. Radiation exposure causes harm to humans and is strictly controlled by several regulatory authorities (NRC, FDA, EPA, DOT, etc). The practice of nuclear medicine involves the use of radioactive materials in patients and research, and is well regulated by these agencies. However, information on radiation safety practice in nuclear medicine and research areas is scattered throughout the literature and federal registers. For busy nuclear technologists and professionals, it is quite time consuming to look for and acquire specific information and instructions to follow in radiation-related occasions and incidents. This guide provides ready-made, handy information on radiation safety as required in the practice of nuclear medicine, presented in a concise form for easy understanding and quick reference related to a given situation and/or incident. This is an ideal reference for nuclear medicine physicians, nuclear medicine technologists, and researchers using radioactive materials.

Contains Applications for Home, Business & Educational Uses as Well as Games. Includes Programs, Printouts, Flowcharts, Diagrams & Illustrations

"This is a comprehensive volume on analytical techniques used in materials science for the characterization of surfaces, interfaces and thin films. This flagship volume is a unique, stand-alone reference for materials science practitioners, process engineers, students and anyone with a need to know about the capabilities available in materials analysis. An encyclopedia of 50 concise articles, this book will also be a practical companion to the forthcoming books in the series."--Knovel.

A spacetime appetizer -- Relatively speaking -- Einstein on trial -- Wave talk and bar fights -- The lives of stars -- Clockwork precision -- Laser quest -- The path to perfection -- Creation stories -- Cold case -- Gotcha -- Black magic -- Nanoscience -- Follow-up questions -- Space invaders -- Surf's up for Einstein wave astronomy