bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane Gas Separation Principles
Authors: Fain D. E. 
Published: August 2016

Some industrial processes require the separation of gas or vapor mixtures. Methods for separating the mixtures vary from separation by diffusion to separation by distillation. Many of the methods, such as distillation, are energy intensive. Membranes can reduce the energy required to produce a desired separation. Because of their corrosion resistance and high temperature applications, engineered inorganic membranes can significantly increase the efficiency of many of these processes. The magnitude of the separation factor, available operating conditions, enrichment, yield, and cost of the membranes play a large role in determining whether membranes can be more economical than other methods of separation. These factors have to be evaluated on a case-by-case basis.Martin Marietta Energy Systems' Office of Technology Transfer conducted a preliminary market survey with the assistance of the University of Tennessee and commercial marketing experts in inorganic membranes. The survey assumed that membranes could be made with permeabilities a factor of 3 larger and with cost per unit area a factor of 3 smaller than is currently available. The results indicated that active implementation of such technology could expect to achieve the following results:• $2 billion dollar per year sales market,• $16.6 billion increase in the national GDP,• $2 billion improvement in the balance of trade, and• 6 quads per year decrease in energy use.
Some Materials Concerns in Nuclear Waste Management
Authors: Hunter Regina L. 
Published: August 2016

The U.S. Environmental Protection Agency (EPA) has determined that deep geologic disposal is appropriate for three types of radioactive waste generated in the United States: spent fuel, high-level waste, and transuranic waste. Spent fuel is nuclear fuel that has been discharged from a reactor after irradiation. High-level waste (HLW) is the highly radioactive material that remains after the reprocessing of spent fuel to recover uranium or plutonium. Transuranic (TRU) waste is any waste material contaminated with more than 100 nCi/g of elements having atomic numbers greater than 92 and half-lives longer than 20 years. Spent fuel and HLW can result from either commercial or governmental activities, although no commercially generated spent fuel has been reprocessed since 1972. TRU waste results primarily from the design and manufacture of nuclear weapons, not from nuclear power plants.The physical characteristics of TRU waste differ substantially from those of spent fuel and HLW. This imposes different requirements on materials associated with containment and isolation, so TRU waste will be discussed separately from spent fuel and HLW Because all three are judged to be particularly dangerous to human beings and the environment, the EPA standard requires a demonstration of adequate 10,000-year performance of geologic repositories for these radioactive wastes. The U.S. Department of Energy (DOE) is responsible for implementing the standard by designing, siting, and building the repositories.This article briefly describes TRU waste, HLW, and spent fuel and the two repositories currently planned by DOE. It con cludes by offering some observations on materials compatibility among waste, container materials, and host rock.
Ion-Beam-Induced Amorphization of Complex Ceramic Materials—Minerals
Authors: Wang L.M. , Ewing R.C. 
Published: August 2016

As early as 1893, mineralogist W.C. Broegger recognized the first example of the transition from the crystalline to aperiodic (amorphous) state in minerals and defined the term “metamikte.” Metamict minerals were considered to be one of three classes of amorphous materials (porodine and hyaline being the other two), but distinguishable as phases that were originally crystalline, as evidenced by well-developed crystal faces. The amorphous state was determined on the basis of a characteristic conchoidal fracture and optical isotropy. There was no mention of radiation damage as a potential cause. In 1914, Hamberg first suggested that metamictization is a radiation-induced, periodic-to-aperiodic phase transition caused by alpha-decay of the constituent radioactive uranium and thorium. In the late 1930s, Stackelberg and Rottenbach tried to test this hypothesis directly by bombarding a thin slab of zircon with alpha particles. Although unsuccessful, the experiment must have been one of the first in which an “ion beam” was used to “modify” a material. After this early effort, there was little research on metamict minerals, and they remained a mineralogical curiosity.R.C. Ewing's interest in this topic began in the early 1970s. Since then, there has been a continuing research program using modern analytical techniques on minerals that have received α-decay doses up to 1026α-decay events/m3over geologic time periods up to 109years. As an example, electron diffraction patterns have shown that naturally occurring zirconolites (CaZrTi2O7) containing varying concentrations of thorium oxide (up to 19 wt% ThO2) are amorphized to different degrees depending on their age and the resulting α-decay event dose (Figure 1).
Ion-Assisted Processing of Electronic Materials
Authors: Brown Walter L. , Ourmazd Abbas 
Published: August 2016

The fabrication of a state-of-the-art silicon chip consists of a carefully composed sequence of “steps.” The length, complexity, and place of each step within this process is analogous to that of a musical phrase within a long sonata. Just as a sonata consists of a series of recurring but evolving themes, a “process” utilizes a number of basic techniques that recur in a variety of contexts. A typical modern process consists of about 350 “steps.” Roughly a fifth of them belong to the class of ionassisted processing. These range from a variety of ion implantation modules, through sputter deposition and reactive ion etching of thin films, to photoresist etching and ashing. Ion-assisted processing thus has a role of major technological importance. With the range of new processes currently under active research, this trend seems likely to continue.The technological applications of ionassisted processing rest on the basic concepts developed in research over the past 30 years. This special issue of the MRS Bulletin reviews the fundamental concepts that underpin this processing today, and highlights areas of current research which may have future technological potential. The emphasis is placed heavily on silicon, both for illustrative purposes, and because Si processing is the major customer for ion-assisted technology. The articles pinpoint areas where materials research can play a critical role in establishing the fundamental understanding needed for a realistic assessment of technological potential.
Materials Science and Engineering Education
Authors: Abbaschian R. 
Published: August 2016

Materials science and engineering (MSE), as a field as well as a discipline, has expanded greatly in recent years and will continue to do so, most likely at an even faster pace. It is now well-accepted that materials are crucial to the national defense, to the quality of life, and to the economic security and competitiveness of the nation. Mankind has recognized the importance of manmade materials to the quality of life for many centuries. In many cases, the security and defense of tribes and nations have substantially depended on the availability of materials. It is not surprising that historical periods have been named after materials—the Bronze Age, the Iron Age, etc. The major requirements from materials in those days were their properties and performance. Today, in this age of advanced materials, the importance of materials to defense and quality of life has not changed. However, the critical role of materials has taken an additional dimension: it has become essential to enhancing industrial competitiveness.The knowledge base within MSE has also expanded vastly throughout these years and continues to do so at an increasing rate. We are constantly gaining a deeper understanding of the fundamental nature of materials, developing new ways to produce and shape them for applications extending from automobiles to supersonic airplanes, optoelectronic devices to supercomputers, hip implants to intraocular lenses, or from household appliances to gigantic structures. We are also learning that, in many of these applications, we need to depend on the combinations or composites of different classes of materials (metals, ceramic, polymers, and electronic materials) to enhance their properties.
Graduate Education for Materials Scientists and Engineers: General, Special, or Fundamental?
Authors: Stiles Phillip J. 
Published: August 2016

What is an appropriate educational program for preparing a PhD to enter the general work force, particularly in materials science and engineering, but also more broadly in all science and engineering fields? The question can be proposed at two different levels: What is the character of the information, knowledge, and the training a student ought to store away and be able to use after leaving the academy, and what specific information or courses does someone need to be an expert?Since I do not have expertise in every aspect of materials science and engineering, and since the latter question can be handled through concerted effort of the appropriate experts, I will focus only on the first question.To paraphrase the first question more starkly, how much of a generalist should a PhD be and how much of a specialist? I will try to define the generalist and specialist in polar perspective, in the sense that I use them:1. A specialist must be grounded in that specialty, conversant with its literature and new findings, and able to converse with other specialists in the field to exchange information and perspectives.2. A generalist must be well-grounded in the fundamentals of numerous fields. It is not necessary to be a specialist in many fields, but a generalist must have access to and be able to find and digest the happenings and literature in these other fields.
An 8,500-Year-Old Sculpted Plaster Head from Jericho (Israel)
Authors: Kingery W. David , Vandiver Pamela B. , Noy Tamar 
Published: August 2016

Jericho (Tell al-Sultan) lies in the Jordan rift valley north of the Dead Sea. Although now remembered as the city where Joshua blew his trumpet and the walls came tumbling down, it was an important settlement long before and long after this late second millennium B.C. battle. Jericho is located close to an important spring and was inhabited during the Natufian period between 11,000 and 9,300 B.C. as an encampment from which cereal grains were collected and gazelle were hunted. In the Aceramic or Pre-Pottery B Neolithic Period (7000–6200 B.C.), the site was the largest village in the area, covering three hectares. Jericho is thought to have had a population of perhaps 1,500 people who developed farming of wheat, barley, legumes, and fruit such as figs, and gradually, the herding of sheep and goats. Salt and bitumin were available to the south in sufficient abundance for trade. Although no pottery vessels were made and fired at this time, the clayey, calcareous soil, reinforced with fibrous dried vegetal material, was used as a ubiquitous building material for houses, storage pits, animal shelters and other structures. Sun-dried bricks were developed in the Pre-Pottery Neolithic A, and they became the common building element.Variations in the color, texture, and properties of the various soils available to the Jericho villagers were well known, as exhibited by the villagers' use of different materials for specific purposes. Our studies have shown that some calcareous soils were used to make lime plaster; others, with considerable clay and sand, were used for brick and mortar; and others consisting of fine, fairly high shrinkage, montmorillonite clays were used for small objects and figurines whose manufacture required considerable plasticity and fine surface detail.
Federal Regulations Create New Challenges in Materials Science
Authors: Yost F.G. 
Published: August 2016

Title 40 of the Code of Federal Regulations is a compendium of rules pertaining to environmental protection, written primarily by the Environmental Protection Agency (EPA). These environmental regulations stand some 19 inches wide on a library shelf and are enclosed by 15 volumes of everchanging information. Each of these volumes contains amendments made to the rules since the last publication of that volume, so the effective dates of new regulations can be difficult to ascertain. Interpreting certain regulations has been difficult for many, the cost of complying with them high, and the eventual impact on the national economy foreseen as gloomy. Few, however, would deny the benefits of a well-planned environmental protection plan and few would sympathize with private corporations that flagrantly ignore regulations, pollute their local environment and, when identified, sustain heavy fines from the EPA.With problems like acid rain, air and groundwater pollution, global warming, ecological system degradation, municipal, industrial, and nuclear waste (and the federal regulations designed to control them), the need for important materials science research and development is great. These opportunities can be compared in magnitude with those provided by the Manhattan Project, during the 1940s and 1950s, and by the semiconductor revolution in later years. The difference between these past projects and the current situation is the way in which funds are appropriated for the research and how the work is performed. Rather than independently funded research performed by multiple organizations, work on environmental problems is witnessing cooperation among industry, government, academia, and the public, with a consequent savings of research monies. This cooperation is often achieved with a consortium of organizations such as SEMATECH or the National Center for Manufacturing Sciences.
Rheology of Cementitious Systems
Authors: Zukoski C.F. , Struble L.J. 
Published: August 2016

Many of the useful properties of Portland cement concrete stem from chemical reactions between cement and water, which cause the slow transformation of the initial fluid suspension into a rigid solid. Because this transformation does not begin immediately, concrete may be processed—mixed, transported, consolidated into a mold, and given a smooth surface — before it becomes rigid (i.e., sets), which typically occurs a few hours after initial mixing. As a result of the need to maintain a workable suspension during processing, the flow properties of cementitious systems have seen considerable attention. However, control of workability remains poorly understood, in part because the relationships between flow and process-ability are not clear. Recent advances have been made in understanding the flow of nonreactive suspensions, and the objective of this article is to explore how these advances provide new insights concerning the behavior of cementitious materials.There are two motivations driving investigations of cement rheology. The first is that understanding flow properties is the key to better processing. The second is that paste rheology can be used to gain a fundamental understanding of the initial cement microstructure and of the variables influencing early cement hydration reactions.
Immobilization Science of Cement Systems
Authors: Macphee D.E. , Glasser F.P. 
Published: August 2016

Portland cement and Ca(OH)2, “slaked lime,” are representative of a family of materials that have conceptual and practical advantages as matrices for the immobilization of wastes. These are relatively proven construction materials with an extensive history of use in various ground-water regimes, and in various climates. The raw materials are widely available and they exhibit a reasonable amount of resistance to physical damage and attrition. They are also durable. Although modern Portland cements are only about 150 years old, numerous examples of Roman concrete made from slaked lime and volcanic pozzolanic ash survive; the Pantheon in Rome (circa A.D. 300) continues in regular use.Satisfactory immobilization matrices can also be formed by incorporating other artificial waste materials, e.g. coal combustion fly ash, blast furnace slag, and natural materials such as calcined kaolin or siliceous volcanic ashes containing glass and zeolites. These materials react with Ca(OH)2 and cement to become an integral part of a cement matrix. Thus one waste (ash, slag) can be used to help immobilize another, and may actually improve the retentive capacity of a cementitious matrix.Since cements require water to harden, they are tolerant of wet wastes and are especially useful for many effluents. In addition, they are low-cost, nonflammable materials with the potential to provide chemical and physical immobilization of wastes, but their set characteristics can be affected by certain material additions. Table I balances some advantages against disadvantages of the use of cement systems for waste immobilization.
The Effect of Materials on Time
Authors: Sullivan Donald B. 
Published: August 2016

We all know that the properties of a material can change with time, but is the inverse possible? How can materials have an effect on time? In the strictest sense, the idea is absurd. However, our ability to keep track of time is clearly dependent on the materials we use to construct our clocks. The performance of many early mechanical clocks depended on the materials of fabrication, and today's high-technology clocks depend no less critically on materials.My objective in this brief article is to divulge a few materials problems involved in clock technology. Since I do not attempt a comprehensive report, I will undoubtedly leave out some issues that colleagues in the field would consider important.Navigation has been a key driving force for the development of accurate timekeeping, at least since the 17th century. While many other important applications require accurate timekeeping (e.g., synchronization for telecommunications and electrical power distribution), I focus on navigation because of its historical significance and its particularly graphic illustration of why clocks have attained such prominence.
Metallization for Integrated Circuit Manufacturing
Authors: Joshi R.V. , Blewer R.S. , Murarka S. 
Published: August 2016

This issue of the MRS Bulletin focuses on current interconnect metallurgies practiced in the manufacturing of integrated circuits (ICs). The issue should serve as a reference for researchers, scientists, engineers, and those who are not familiar with the IC arena.Al-metallization requires special attention due to its wide usage in logic and memory circuits. Logic requirements drive technology toward improved circuit performance while memory improvements require high device and wiring densities. As the dynamic random access memory (DRAM) evolves from 64 Mbits to 256 Mbits, ultralarge-scale integrated (ULSI) wiring will decrease to below sub-0.3 μm in dimensions. Such circuits require robust, reliable back end of the line (BEOL) technology that meets high-performance, low-cost, stringent electromigration requirements. We feel that several of these emerging interconnect fabrication techniques have reached a sufficient level of maturity to warrant a reasonable exposition. We will concentrate on metallization systems in this issue, leaving a discussion of dielectrics for the future, due to space limitations.The semiconductor industry has relied on aluminum technology since the 1960s because it is a well-established, low-cost technology. Early improvements in the electromigration resistance of Al lines by the addition of Cu impurities after 1971 helped this metallurgy to endure further feature size reductions, without degradation of reliability. However, the relentless reduction in via and line size once again may bring into question the limitation of Al reliability. As a result, work on alternate low-resistivity and high-electromigration-resistant metals like Cu is continuing in parallel.
Ion Tracks in Solids: From Science to Technology to Diverse Applications
Authors: Fleischer Robert L. 
Published: August 2016

Fast ions create linear trails of intense atomic disorder in many solids. Theparticle tracksare in themselves scientifically interesting because they consist of unique, localized radiation damage. They also are noteworthy for their diverse practical uses, which range from improved high field superconductors to mineral exploration and bird altimetry. The two areas—what tracks are and what they do practically—are the subjects of this introduction and the following three articles. Although the mechanism for producing tracks in insulators is semi-quantitatively well-established, there is a distinct mystery as to the formation mechanism in superconductors, inter-metallics, and metals. This mystery is the subject of the next two articles written by discoverers of tracks in these materials.We will not discuss in detail the multitude of scientific uses for these tracks as particle-track detectors. Uses range from nuclear, elementary-particle, and cosmic-ray physics to geochronology, geochemistry, and geophysics; chemistry; and radiobiology. The interested reader can learn more on the subject through a book, part of which surveys scientific applications of particle tracks in solids. The key to these uses—and most of the practical uses—is that, in materials where tracks can be observed, either directly or by a widely applicable trick to be described, each detector sample is a nuclear particle-track chamber—the solid-state equivalent of the well-known gaseous and liquid detectors (i.e., cloud chambers and bubble chambers). The major distinction is that tracks in solids are long-lasting rather than transient features.
The Shell Model and Interatomic Potentials for Ceramics
Authors: Stoneham Marshall , Harding John , Harker Tony 
Published: August 2016

In a classification of solids according to their bonding character (into metals, ceramics and glasses, polymers, and semiconductors), the ceramic class includes an enormous range of industrially important materials. From the archetypal ionic solids through oxides to silicates, and to covalently bonded materials such as SiC, they exhibit a rich variety of structures and properties. They occur as structural materials, either on their own or as composites such as SiC/Al2O3. They are important functional materials, such as fast-ion conductors as electrolytes in fuel cells (for example ZrO2/Y2O3 for hydrogen combustion) or batteries (β-alumina in the sodium-sulfur battery), ferroelectric materials such as BaTiO3 and piezoelectrics such as PZT—a solid solution of PbTiO3 and PbZrO3. The high-temperature superconductors (for example, YBa2Cu3O7) are ceramics above the superconducting transition temperature. The products of corrosion and oxidation are ionic materials, and the properties of oxide coatings are vital to the survival of high-temperature alloys in gas turbines or fuel-element claddings in nuclear reactors.To understand the behavior of ceramic materials, and to optimize their production, processing, and application, it is often necessary to model their behavior at an atomic level. In some cases this is obvious. Ionic diffusion in a solid electrolyte is a self-evidently atomic process. In other cases the need for atomistic simulation is less clear. Oxidation, for example, is a subtle blend of atomic diffusion (often along grain boundaries), metal-ceramic bonding, stress relief, and grain growth. The course of oxidation can be spectacularly affected by impurities and alloying, and this can only be understood by considering the atomicscale processes involved.