The mean heat capacity of a sample of powdered beryllium carbide, a possible moderator material for a nuclear reactor, was determined as a function of temperature. A thin-walled stainless steel capsule containing the material was heated in an electric furnace and dropped into a water calorimeter. The following linear equation for mean heat capacity over the temperature range 50 f C-T f C as a function of temperature, T, was derived from the data by the method of least squares: C/sub p/ = 0.299 + 2.16 x 10−4 T f C el temperatures 0.005 cal gm−1(f C)/sup -1/. The numerical value of C/sub p/ expressed by this equation is also equal to the mean heat capacity in Btu lb−1(f F)−1. (auth).

Mineral Commodity Summaries 2019

The growth and development witnessed today in modern science, engineering, and technology owes a heavy debt to the rare, refractory, and reactive metals group, of which niobium is a member. Extractive Metallurgy of Niobium presents a vivid account of the metal through its comprehensive discussions of properties and applications, resources and resource processing, chemical processing and compound preparation, metal extraction, and refining and consolidation. Typical flow sheets adopted in some leading niobium-producing countries for the beneficiation of various niobium sources are presented, and various chemical processes for producing pure forms of niobium intermediates such as chloride, fluoride, and oxide are discussed. The book also explains how to liberate the metal from its intermediates and describes the physico-chemical principles involved. It is an excellent reference for chemical metallurgists, hydrometallurgists, extraction and process metallurgists, and minerals processors. It is also valuable to a wide variety of scientists, engineers, technologists, and students interested in the topic.

This volume from The NASA History Series presents an overview of the science of hypersonics, the study of flight at speeds at which the physics of flows is dominated by aerodynamic heating. The survey begins during the years immediately following World War II, with the first steps in hypersonic research: the development of missile nose cones and the X-15; the earliest concepts of hypersonic propulsion; and the origin of the scramjet engine. Next, it addresses the re-entry problem, which came to the forefront during the mid-1950s, showing how work in this area supported the manned space program and contributed to the development of the orbital shuttle. Subsequent chapters explore the fading of scramjet studies and the rise of the National Aerospace Plane (NASP) program of 1985–95, which sought to lay groundwork for single-stage vehicles. The program's ultimate shortcomings — in terms of aerodynamics, propulsion, and materials — are discussed, and the book concludes with a look at hypersonics in the post-NASP era, including the development of the X-33 and X-34 launch vehicles, further uses for scramjets, and advances in fluid mechanics. Clearly, ongoing research in hypersonics has yet to reach its full potential, and readers with an interest in aeronautics and astronautics will find this book a fascinating exploration of the field's history and future.

Provides a thorough explanation of the basic properties of materials; of how these can be controlled by processing; of how materials are formed, joined and finished; and of the chain of reasoning that leads to a successful choice of material for a particular application. The materials covered are grouped into four classes: metals, ceramics, polymers and composites. Each class is studied in turn, identifying the families of materials in the class, the microstructural features, the processes or treatments used to obtain a particular structure and their design applications. The text is supplemented by practical case studies and example problems with answers, and a valuable programmed learning course on phase diagrams.