bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cosmonauts Selection and Preparation
Authors: Egorov Alexander N. , Sosyurka Yu.B. , Yaropolov V.I. 
Published: October 2003

Abstract
The Soviet Union's launch of the world's first artificial Earth satellite on 4 October 1957 and its subsequent achievements in developing rockets and space technology and flying living beings in its space flight program marked the beginning of preparations for the first human spaceflight. The issue of human spaceflight was discussed in the USSR Academy of Sciences as early as the very beginning of 1959.
Selection of the first cosmonauts began in October 1959 among men in Air Force units. It was believed that the best candidates for the first piloted spaceflight would come from the ranks of military pilots. Documents for more than 3000 fighter pilots, aged 35 or below, were examined to select the first cosmonaut candidates. Only 29 pilots passed all phases of medical selection and, of these, 20 were accepted into the spaceflight training program (subsequently, requirements for cosmonaut health standards were relaxed somewhat).
The first group of cosmonauts trained at the Cosmonaut Training Center included Yu.A. Gagarin, who completed an orbital flight of 1 hour 48 minutes on the Vostok‐1 piloted spacecraft on 12 April 1961. After Gagarin's flight, G.S. Titov was trained to perform a 1‐day space flight. This flight was completed in August 1961. The next phase of the Center's activity focused on training cosmonauts for group flights. Subsequently, the Center entered a phase in which cosmonauts were trained for flights on the multiman piloted spacecraft of the Voskhod series, which had just been developed. Training these crews emphasized the use of the new capabilities these spacecraft had for conducting scientific, technological, and biomedical experiments and enabling extravehicular activity.
In 1966 Center specialists began to train cosmonauts in a program involving testing and a series of flights on the new multiperson, multipurpose piloted spacecraft of the Soyuz series, which possessed technical capacities that significantly exceeded those of Vostok.
This article gives the history of the various training programs implemented at the Center. Programs included training for lunar landings, the Almaz space station and the Salyut 4 long‐term space station. The Center is now participating in the training of astronauts and cosmonauts to support the International Space Station.
As space technology developed, the goals, structure, and technical facilities underwent change. The main activities of the Center are given in detail.
Mars
Authors: Considine Glenn D. 
Published: October 2003

AbstractThe fourth planet from the Sun, Mars is the first planet in the solar system beyond Earth. Compared with Earth, Mars is a small planet. With a value of 1.00 for Earth, the mass of Mars is 0.107; the density, 0.719; volume, 0.149. The equatorial diameter of Mars is 4,226 miles (6,772 kilometers) as compared with that of earth of 7,960 miles (12,757 kilometers). Although Mars has been observed since early times, reliable and detailed data did not become available until commencement of theMarinerexploratory program in the 1960's. With theVikingprograms of the last half of the 1970s, some importantMarinerdata had to be revisedMars has two satellites, or moons, Phobos and Deimos, both discovered in 1877 by Hall. Spacecraft have shown these bodies to be cratered, rocky, and chunky, and in recent years there has been serious speculation that these may not be moons in the usual sense, but rather captive asteroids. (See also Asteroids.) Phobos is quite small, with dimensions of approximately 12.4×17.4 miles (20×28 kilometers) and Deimos even smaller, 6.2×9.9 miles (10×16 kilometers). These satellites were visited during theVikingmissions.The twinVikingmissions to Mars, each with its own lander, represented a very sophisticated and successful venture. Among some scientists there remains perplexity regarding some of the main features of the planet, notably numerous channels and rifts at one time called “canals” by Earth‐bound observers several decades ago. Knowledge of how these features look (including full‐color) and their dimensions have been greatly enhanced, but the mysteries of their origins remains unknown. Earth‐bound estimates andMariner'smeasurements of Mars comparatively thin atmosphere were confirmed, a factor which detracted from the possibility of organisms living on the planet. The polar ice cap once thought to be frozen carbon dioxide has been found to be ice with possibly some frozen carbon dioxide with it other findings related to weather, age of Mars, and volcanisms are discussed. Biological experiments designed to detect living organism proved negative, but the apparently oxidizing characteristic of Martian soil has introduced new puzzles.TheVikingmissions are discussed in detail. PostVikingmissions using radar and and enquiry into the possibility of a peopled mission are detailed.
Common Concepts in Materials Characterization
Authors: Kaufmann Elton N. 
Published: October 2003

Abstract
From a tutorial standpoint, one may view this article as a good preparatory entrance to subsequent articlesin this Encyclopedia. In an educational setting, the generally applicable topics of the articles in this category can play such a role, notwithstanding that they are each quite independent without having been sequenced with any pedagogical thread in mind.
In practice, it is expected that each of these article of this chapter will be separately valuable to users of the encyclopedia as they choose to refer to it for concepts underlying many of those exposed in units covering specific measurement methods.

Of course, not every topic covered by a section in this article will be relevant to
every
measurement method covered in subsequent articles in this Encyclopedia. However, the concepts in this article are sufficiently common to appear repeatedly in the pursuit of materials research.
General Vacuum Techniques
Authors: Singleton Jack H. 
Published: October 2003

AbstractIn this article we discuss the procedures and equipment used to maintain a vacuum system at pressures in the range from 10−3to 10−11torr are discussed. Total and partial pressure gauges used in this range are also described.Because there is a wide variety of equipment, each of the various components is described, including details of their principles and technique of operation, as well as their recommended uses.SI units are not used here. The American Vacuum Society attempted their introduction many years ago, but the more traditional units continue to dominate in this field in North America. Usage is consistent with that generally found in the current literature.The most difficult step in designing and building a vacuum system is defining precisely the conditions required to fulfill the purpose at hand. Important factors to consider are included. Pumps play an important roll in a vacuum system. Details on pumps for the operation of most vacuume systems are given. Leak detection is addressed.
Mass and Density Measurements
Authors: Dollimore David , Samuels Alan C. 
Published: October 2003

Abstract
The precise measurement of mass is one of the more challenging measurement requirements that materials scientists must deal with. The use of electronic balances has become so widespread and routine that the accurate measurement of mass is often taken for granted. While government institutions such as the National Institutes of Standards and Technology (NIST) and state metrology offices enforce controls in the industrial and legal sectors, no such rigors generally affect the research laboratory. The process of peer review seldom makes assessments of the accuracy of an underlying measurement involved unless an egregious problem is brought to the surface by the reported results. In order to ensure reproducibility, any measurement process in a laboratory should be subjected to a rigorous and frequent calibration routine. This article will describe the options available to the investigator for establishing and executing such a routine; it will define the underlying terms, conditions, and standards, and will suggest appropriate reporting and documenting practices. The measurement of mass, which is a fundamental measurement of the amount of material present, will constitute the bulk of the discussion. However, the measurement of derived properties, particularly density, will also be discussed, as well as some indirect techniques used particularly by materials scientists in the determination of mass and density, such as the quartz crystal microbalance for mass measurement and the analysis of diffraction data for density determination.
Thermometry
Authors: Dollimore David , Samuels Alan C. 
Published: October 2003

AbstractThermometry is the science of measuring temperature, and thermometers are the instruments used to measure temperature. Temperature must be regarded as the scientific measure of “hotness” or “coldness.” This article is concerned with the measurement of temperatures in materials of interest to materials science, and the notion of temperature is thus limited in this discussion to that which applies to materials in the solid, liquid, or gas state (as opposed to the so‐called temperature associated with ion gases and plasmas, which is no longer limited to a measure of the internal kinetic energy of the constituent atoms).A brief excursion into the history of temperature measurement will reveal that measurement of temperature actually preceded the modern definition of temperature and a temperature scale.The simple expedient of sealing the instrument so that the liquid and gas were contained in the tube really marks the invention of a glass thermometer. By making the diameter of the tube small, so that the volume of the gas was considerably reduced, the liquid dilation in these sealed instruments could be used to indicate the temperature. Fahrenheit eventually substituted mercury for the “spirits of wine” earlier used as the working liquid fluid, because mercury's thermal expansion with temperature is more nearly linear. Temperature scales were then invented using two selected fixed points—usually the ice point and the blood point or the ice point and the boiling point.The starting point for the thermodynamic treatment of temperature is to state that it is a property that determines in which direction energy will flow when it is in contact with another object. Heat flows from a higher‐temperature object to a lower‐temperature object. When two objects have the same temperature, there is no flow of heat between them and the objects are said to be in thermal equilibrium. Development of the International Temperature Scale of 1990 is detailed. Various types of thermometer are discussed as well as the need, sometimes, to control the temperature.
Symmetry in Crystallography
Authors: Steinfink Hugo 
Published: October 2003

Abstract
The study of crystals has fascinated humanity for centuries, with motivations ranging from scientific curiosity to the belief that they had magical powers. Early crystal science was devoted to descriptive efforts, limited to measuring interfacial angles and determining optical properties. Some investigators, such as Haüy, attempted to deduce the underlying atomic structure from the external morphology. These efforts were successful in determining the symmetry operations relating crystal faces and led to the theory of point groups, the assignment of all known crystals to only seven crystal systems, and extensive compilations of axial ratios and optical indices. Roentgen's discovery of x rays and Laue's subsequent discovery of the scattering of x rays by crystals revolutionized the study of crystallography: crystal structures—i.e., the relative location of atoms in space—could now be determined unequivocally. The benefits derived from this knowledge have enhanced fundamental science, technology, and medicine ever since and have directly contributed to the welfare of human society.
This article is designed to introduce those with limited knowledge of space groups to a topic that many find difficult.
Particle Scattering
Authors: Bastasz Robert , Eckstein Wolfgang 
Published: October 2003

Abstract
Atomic scattering lies at the heart of numerous materials‐analysis techniques, especially those that employ ion beams as probes. The concepts of particle scattering apply quite generally to objects ranging in size from nucleons to billiard balls, at classical as well as relativistic energies, and for both elastic and inelastic events. This article summarizes two fundamental topics in collision theory: kinematics, which governs energy and momentum transfer, and central‐field theory, which accounts for the strength of particle interactions.
Definitions of symbols used throughout this article are given in an appendix.
Sample Preparation for Metallography
Authors: Gokhale Atul B. 
Published: October 2003

AbstractMetallography, the study of metal and metallic alloy structure, began at least 150 years ago with early investigations of the science behind metalworking.Metallographic sample preparation has evolved from a black art to the highly precise scientific technique it is today. Its principal objective is the preparation of artifact‐free representative samples suitable for microstructural examination. The particular choice of a sample preparation procedure depends on the alloy system and also on the focus of the examination, which could include process optimization, quality assurance, alloy design, deformation studies, failure analysis, and reverse engineering. The details of how to make the most appropriate choice and perform the sample preparation are the subject of this unit.Metallographic sample preparation is divided broadly into two stages. The aim of the first stage is to obtain a planar, specularly reflective surface, where the scale of the artifacts (e.g., scratches, smears, and surface deformation) is smaller than that of the microstructure. This stage commonly comprises three or four steps: sectioning, mounting (optional), mechanical abrasion, and polishing. The aim of the second stage is to make the microstructure more visible by enhancing the difference between various phases and microstructural features. This is generally accomplished by selective chemical dissolution or film formation—etching. The procedures discussed in this article are also suitable (with slight modifications) for the preparation of metal and intermetallic matrix composites as well as for semiconductors. The modifications are primarily dictated by the specific applications, e.g., the use of coupled chemical‐mechanical polishing for semiconductor junctions.The basic steps in metallographic sample preparation are straightforward, although for each step there may be several options in terms of the techniques and materials used. Also, depending on the application, one or more of the steps may be elaborated or eliminated. This article provides guidance on choosing a suitable path for sample preparation, including advice on recognizing and correcting an unsuitable choice.This discussion assumes access to a laboratory equipped with the requisite equipment for metallographic sample preparation. Listings of typical equipment and supplies and World Wide Web addresses for major commercial suppliers are provided for readers wishing to start or upgrade a metallography laboratory.
Computation and Theoretical Methods
Authors: Sanchez Juan M. 
Published: October 2003

Abstract
The articles in this category of have been selected to provide the reader with a suite of theoretical and computational tools, albeit at an introductory level, that begins with the microscopic description of electrons in solids and progresses towards the prediction of structural stability, phase equilibrium, and the simulation of microstructural evolution in real materials. This section also includes articles devoted to the theoretical principles of well established characterization techniques that are best suited to provide exacting tests to the predictions emerging from computation and simulation. It is envisioned that the topics selected will accurately reflect significant and fundamental developments in the field of computational materials science. Due to the nature of the discipline, these articles are likely to evolve as new algorithms and computational methods are developed, providing not only an up‐to‐date overview of the field, but also an important record of its evolution.
Introduction to Computation
Authors: Ceder Gerbrand 
Published: October 2003

AbstractAlthough the basic laws that govern the atomic interactions and dynamics in materials are conceptually simple and well understood, the remarkable complexity and variety of properties that materials display at the macroscopic level seem unpredictable and are poorly understood. Such a situation of basic well‐known governing principles but complex outcomes is highly suited for a computational approach. This ultimate ambition of materials science—to predict macroscopic behavior from microscopic information (e.g., atomic composition)—has driven the impressive development of computational materials science. This article is a brief introduction to the set of articles in this category. The ultimate advantage of computing methods, both in basic materials research and in applied materials design, is the level of control one has over the system under study. The parts of this category deal with a large variety of physical phenomena.
Prediction of Phase Diagrams
Authors: Didier de Fontaine 
Published: October 2003

AbstractA phase diagram is a graphical object, usually determined experimentally, indicating phase relationships in thermodynamic space. Usually, one coordinate axis represents temperature; the others may represent pressure, volume, concentrations of various components, and so on. This unit is concerned only with temperature‐concentration diagrams, limited to binary (two‐component) and ternary (three‐component) systems. Since more than one component is considered, the relevant thermodynamic systems are alloys, by definition, of metallic, ceramic, or semiconductor materials. The emphasis here is placed primarily on metallic alloys.Phase diagrams can be classified broadly into two main categories: experimentally and theoretically determined. The object of the present unit is the theoretical determination—i.e., the calculation of phase diagrams, meaning ultimately their prediction. But calculation of phase diagrams can mean different things: there are prototype, fitted, and first‐principles approaches. Prototype diagrams are calculated under the assumption that energy parameters are knowna priorior given arbitrarily. Fitted diagrams are those whose energy parameters are fitted to known, experimentally determined diagrams or to empirical thermodynamic data. First‐principles diagrams are calculated on the basis of energy parameters calculated from essentially only the knowledge of the atomic numbers of the constituents, hence by actually solving the relevant Schrödinger equation.Theory also enters in the experimental determination of phase diagrams, as these diagrams not only indicate the location in thermodynamic space of existing phases but also must conform to rigorous rules of thermodynamic equilibrium (stable or metastable). The fundamental rule of equality of chemical potentials imposes severe constraints on the graphical representation of phase diagrams, while also permitting an extraordinary variety of forms and shapes of phase diagrams to exist, even for binary systems.That is one of the attractions of the study of phase diagrams, experimental or theoretical: their great topological diversity subject to strict thermodynamic constraints. In addition, phase diagrams provide essential information for the understanding and designing of materials, and so are of vital importance to materials scientists. For theoreticians, first‐principles (orab initio) calculations of phase diagrams provide enormous challenges, requiring the use of advanced techniques of quantum and statistical mechanics.
Simulation of Microstructural Evolution Using the Field Method
Authors: Wang Y. , Chen L.‐Q. 
Published: October 2003

AbstractMorphological pattern formation and its spatio‐temporal evolution are among the most intriguing natural phenomena governed by nonlinear complex dynamics. These phenomena form the major study subjects of many fields including biology, hydrodynamics, chemistry, optics, materials science, ecology, geology, geomorphology, and cosmology, to name a few. In materials science, the morphological pattern is referred to as microstructure, which is characterized by the size, shape, and spatial arrangement of phases, grains, orientation variants, ferroelastic/ferroelectric/ferromagnetic domains, and/or other structural defects. These structural features usually have an intermediatemesoscopiclength scale in the range of nanometers to microns.Microstructure plays a critical role in determining the physical properties and mechanical behavior of materials. Today the primary task of material design and manufacture is to optimize microstructures— by adjusting alloy composition and varying processing sequences—to obtain the desired properties.Microstructural evolution is a kinetic process that involves the appearance and disappearance of various transient and metastable phases and morphologies. The optimal properties of materials are almost always associated with one of these nonequilibrium states, which is “frozen” at the application temperatures. Theoretical characterization of the transient and metastable states represents a typical nonequilibrium nonlinear and nonlocal multiparticle problem. This problem generally resists any analytical solution except in a few extremely simple cases.With the advent of and easy access to high‐speed digital computers, computer modeling is playing an increasingly important role in the fundamental understanding of the mechanisms underlying microstructural evolution. In this article, methods recently developed for simulating the formation and dynamic evolution of complex microstructural patterns are reviewed. First, a brief account of the basic features of each method, including the conventional front‐tracking method (also referred to as the sharp‐interface method) and the new techniques without front‐tracking are given. Detailed description of the simulation technique and its practical application focuses on the field method since it is the most familiar and it is a more flexible method with broader applications. The need to link the mesoscopic microstructural simulation with atomistic calculation as well as with macroscopic process modeling and property calculation is also briefly discussed.