In the early years of doping of semiconductors by ion implantation, atomic displacements and residual lattice damage were considered undesirable byproducts of an otherwise controllable doping process. Steps were taken to minimize disorder during implantation and/or to remove it as completely as possible during a subsequent annealing process. In many cases, such as boron- or phosphorus-implanted silicon, annealing temperatures exceeding 900°C were necessary to achieve the desirable electrical properties. Indeed, removal of implantation damage remains a crucial issue, particularly as device dimensions shrink and the need has arisen for substantially lower processing temperatures. The advent of high-energy (MeV) implantation in specific processing steps and the increasing use of more complex (often multilayer) compound semiconductors has added further to the need to understand and control ion damage and its annealing in semiconductors.

Over the past decade, there has been a growing realization that implantation induced atomic displacements and defects can have significant advantages in processing. For example, it was realized early that ion damage, and resultant defect fluxes to and from lattice disruptions, can “getter” and trap undesirable impurities that would otherwise interfere with device operation. More recently, it has been possible to use ion beams to tailor damage structures and form amorphous-crystalline superlattices, to remove pre-existing damage and induce crystallization of amorphous layers at very low temperatures, to form ultrapure amorphous silicon for studying thermodynamic properties of this phase, or to mix films with semiconductors and form stable compounds such as silicides. Indeed, ion damage has been used to electrically isolate devices, to form optical waveguides and cavities, and to improve the junction properties of deeply doped layers. These issues are briefly reviewed in this article.

Majolica pottery is an earthenware covered with lead glaze opacified and whitened by adding a small percentage of tin oxide. The technology of majolica production, a Muslim contribution, was introduced into Spain and then diffused to the Western Hemisphere in the course of colonization very soon after the Spanish arrival in Mexico in 1521. (See Table I for Majolica production sources and excavation sites.)

In the 1980s there were two references on the organization of majolica production in both Spain and the New World. Descriptions of the layouts of the potters' workshops, of the sources of the clays, how the kilns were used, and how the glazes were made are taken from historical and ethnographic sources. These authors also discuss the interesting and important effect of the presence of Italian potters in both Seville and the New World. However, little has been written based on archaeologically excavated material from Seville, the main source of supply to the New World, or from known Puebia or Mexico City production.

In the 1970s a project involving neutron activation analysis of Spanish majolica ceramics was developed through the cooperative efforts of Malcolm Watkins and Richard Ahlborn of the National Museum of American History, Charles Fairbanks of the University of Florida, and Jacqueline Olin. Neutron activation analysis provides precise simultaneous determination of the concentrations of up to 35 elements. Two chemically distinct groups of ceramics were identified among sherds excavated at New World sites. They could be stylistically divided between Spanish and Mexican production with some important exceptions.

The terms “teamwork” and “statistical quality control” (SQC) have become an established part of U.S. manufacturing vocabulary, though not necessarily of manufacturing practice. Much has been written on these subjects, as even a cursory glance at the literature reveals (e.g., see References 1–11). This article will describe the organization and functioning of an SQC team at Owens-Corning Fiberglas Corporation. My observations are not necessarily novel, but I hope they provide some useful insights into team building, teamwork, and SQC in a U.S. manufacturing environment.

SQC is not a new concept at all, but it was largely ignored in the United States. The contribution of SQC (more accurately, Deming's and Juran's SQC precepts) to Japanese manufacturing quality has by now become a matter of folklore. This does not mean, however, that the SQC “philosophy” is correctly understood by U.S. companies. SQC is often viewed too narrowly as a production tool, or S and C in SQC are given undue attention. SQC is much more than a collection of statistical techniques. Indeed, the major impact of SQC results not from its engineering or technical attributes but from the changes it brings about in attitudes and in a factory's social organization. Drucker has identified SQC as one of the four concepts in the emerging theory of manufacturing.

Silks produced by silkworms (e.g., Bombyx mori) and orb-web weaving spiders (e.g., Nephila clavipes) are essentially pure protein, that is, complexes of amino acid polymers. They are the most common fibers spun by biological systems. There has been a long-standing interest in the use of these and similar fibers in textiles, cables, fiber reinforcement in composites, in addition, for example, to cross hairs in optical instruments, and fishing nets. Both nylon, a homo-polymer of the amino acid glycine, and Kevlar, a polymer of a nonnatural aromatic amino acid, can be considered modified, synthetic versions of silk and are used for some of the applications mentioned above. The potential for genetic manipulation, through recombinant DNA technology, of the natural biosynthetic process for these natural proteins (see the article by Cappello in this issue) has renewed interest in the production of new silklike proteins.

The natural silks are characterized by a β-sheet secondary structure which is stabilized by interchain hydrogen bonds and intersheet hydrophobic interactions (Figure 1). Silks can be considered block copolymers, with crystalline domains consisting of short side chain monomers (the amino acids glycine, alanine, and serine) interspersed in amorphous domains consisting of bulkier side chain amino acids.

This family of fibers is naturally tailored to perform functions such as catching prey (orb web) or serving as a barrier against environmental challenges (cocoon). The domestic silkworm (B. mori) produces only one type of silk, cocoon silk, at only one stage in its lifecyle, during the fifth larval instar just before molt to the pupa. The silk is produced in modified salivary glands and spun from the mouth.

Despite the discovery of the laser a few decades ago, the potential for pulsed laser deposition (PLD) of thin films has remained unexploited. Despite the sustained pioneering work at Rockwell in laser deposition, it took the development of high-temperature superconductors to fully realize the technique's potential. Early work on PLD of high-temperature superconductors demonstrated for the first time that the composition of rather complex multi-elementary materials can be reproduced in the deposited film under appropriate conditions of laser energy density and deposition angle. These features made PLD unique; and once the recipe for making in-situ crystalline films of proper stoichiometry was known, the technique's popularity was significantly enhanced in the research community.

The features of laser deposition that make the process so unique, and that are discussed throughout this issue, are recapped below:

1. Rather complex multi-elementary materials can be deposited well if a single-phase, homogeneous target can be fabricated. The complexity of the deposition process is translated to the relatively easier process of fabricating a high-quality target.

2. The chamber pressure, target-substrate distance, target orientation with respect to the laser beam, etc. are significantly de-coupled, enabling significant freedom in deposition system design. The target is decoupled from the substrate in the sense that a small target can be used to deposit film over a fairly large area substrate with the appropriate scanning schemes.

3. The efficiency of the target use is superior compared to any other technique since a predominant amount of the evaporated material is forward directed and can be collected with a high degree of efficiency. For example, in a production environment, more than 100 YBCO films (ranging 3,000-4,000 Å thick) on 1 × 1 cm2 substrates have been fabricated from a 0.25-inch-thick one-inch target with a majority of the target still left over. The cost of raw materials in a production environment may become significant, and for toxic elements particularly there is a further advantage in minimizing the spread of contaminants.

Since the first report of superconductivity in the Bi-Sr-Ca-Cu-O (BSCCO) system by Maeda et al., an enormous quantity of material work has been reported on the Bi system. The Bi-2223 phase exhibits a zero-resistivity temperature of around 110 K and this is the highest critical temperature outside the 125 K critical temperature found in the Tl-Ba-Ca-Cu-O system. The layered BSCCO phases cleave easily, making it possible to align grains by a deformation process.

The powder-in-tube method is one of the fabrication processes that permits grain alignment and the achievement of high critical current density. This tendency is particularly strong for the 2223-BSCCO phase.

In this paper, we report on the relation between the critical current density (Jc) and the microstructure in silver-sheathed Bi-Pb-Sr-Ca-Cu-0 (2223) wires produced by the powder-in-tube method.

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.

In 1971, the first halobacterial retinal protein was discovered and named bacteriorhodopsin. Bacteriorhodopsin (BR) is a protein of 248 amino acids that is integrated into the bacterial membrane. It is a light driven pump, moving protons from the inside to the outside of the cell. The resulting gradient drives the production of ATP (adenosine triphosphate) for the organism. In the 1970s, rapidly growing research activities focused on the biochemical and biophysical properties of BR and resulted in a linearly increasing number of publications per year. The constant level of about 200 publications/year in the last decade signifies the steadily growing knowledge about the structure and bioenergetic function of BR and related molecules. Nowadays, BR is one of the best-investigated membrane proteins (e.g., References 3–10).

Only five years after the unusual chemical and photophysical properties of BR were reported, several articles appeared suggesting technical applications of BR for sunlight energy conversion. Although no commercial applications of BR have resulted from these studies, new ideas for application have arisen, covering about 10% of the total publications on BR during the last two years. Is this an indicator of real potential for BR as a biological material in technology?

I would like to raise a question of interest to many of us here today: “Why have we not been able to find a room-temperature superconductor?” I have a scenario for why not that can be illustrated by projecting ahead 98 years. It is 2089, the tercentenary of the French Revolution. The revolt against science that started building up in the last decade of the 20th century has reached a crescendo and a revolutionary tribunal has erected a huge guillotine. Following in the tradition of Lavoisier's trial and execution, the presidents of the Materials Research Society, the American Chemical Society, and the American Physical Society have been found to be enemies of the people and have been sentenced to be guillotined. The president of the Materials Research Society steps up. In his final words, he says: “I have no regrets. We've supplied you with the pole vaults which have made possible a new world's record above 30 feet, we've given you automobile bumpers that prevent damage in crashes at 60 miles per hour, and we've given you tennis rackets that are big enough to allow you to cover from center court to the alley without having to take a step.” With that, he bravely puts his head on the block. Down crashes the knife but inexplicably it stops just before it reaches his neck. According to the rules he steps down a free man. Then the American Chemical Society president steps up and says: “I don't have any regrets either. We have given you body centered cubic diamond that makes it possible to build indestructible houses, we have given you disposable diapers that are biodegradable in 30 seconds, and we've reseeded the stratosphere with ozone. We have done our job.” She courageously puts her head on the block, and the guillotine comes down. Again it stops short and she walks away, a free woman. Then the president of the American Physical Society says: “I don't have any regrets either. We've circled the equator with our newest SSC and have given you the Higgs boson, we've given you light that you can squeeze until it hurts, and we've discovered over 100 theoretical models which should lead to room-temperature superconductors. We haven't given you any real ones because there aren't any—we've tested all the possibilities. But, by the way, while we've been standing here, I've done a back-of-the-envelope calculation and I've found out wha's wrong with this guillotine. If you give me a screwdriver I can fix it.”

CFCs proved to be one of the more useful classes of compounds ever developed because of their many desirable properties. They promote worker and consumer safety because they are nonflammable, noncorrosive, and very low in toxicity. They are used in a wide variety of applications, such as refrigerants, foam blowing agents, and cleaning solvents, because of their desirable physical properties that enhance energy efficiency and product reliability.

However, some of the properties that make CFCs desirable from a worker and consumer safety and applications standpoint have led to global environmental concerns. Because of their chemical stability, CFCs have long environmental residence times, and emissions lead to accumulation in the lower atmosphere. CFCs slowly mix into the upper atmosphere where they dissociate, releasing chlorine atoms that can catalyze destruction of ozone. Recent scientific findings have clearly linked chlorine from CFCs and other man-made compounds and bromine from man-made and natural sources to the seasonal ozone losses over Antarctica, the Antarctic ozone hole, and have indicated that these compounds are probably causing ozone losses over populated areas of both the northern and southern hemispheres as well. Since ozone provides a screen against solar ultraviolet radiation (UV-B) and excess UV-B has a potential to contribute to health and environmental concerns, significant reductions in ozone should be avoided. This information provides a sound basis for the Montreal Protocol, an international agreement amended in 1990 requiring a total phaseout of CFC production and consumption by 2000.

Biological membranes provide numerous functions for the survival of cells, ranging from molecular recognition to signal transduction and energy conversion. The spacial organization of proteins, enzymes, glycoproteins, and glycolipids in the membrane is provided by the lipid bilayer matrix. The lipids of the membrane are small molecules which have the common characteristic of having both a hydrophilic and a hydrophobic moiety. In aqueous media, they are entropically driven to self-organize in bimolecular sheets (see the article by Alper in this issue). These sheets, in addition to providing a fluid matrix for a wide variety of biomolecules, also serve to impede the flow of molecules across the membrane.

A goal of polymer chemistry is to control the final properties of a processed material by controlling the chemistry and physics of the polymer chain. Since the final formulated materials' properties are a complex function of chemical and physical interactions at both the micro and macro scales, it would be desirable to influence those interactions at the level of the molecular chemistry of the chain. However, in order to affect those macromolecular associations that occur via chemical functionalities separated over long distances, a chemistry is needed that can specify not only variability in chemical composition along the chain but can also specify the positions at which this chemical variability must occur over the entire length of the chain—several hundred nanometers.

Protein-based materials in nature are formulated from protein chains which have evolved chemical compositions that through the specific sequence of their amino acid monomer constituents can result in diverse materials such as ultrahigh strength fibers, silks and collagens, and soft, ultradurable elastomers, elastin. As described in the article by Kaplan in this issue, the fundamental six amino acid repeat of the crystalline fraction of Bombyx mori silk fibroin is composed of essentially three amino acids, glycine (G), alanine (A), and serine (S), in a 3:2:1 ratio. The strength of the fiber is derived from these crystallized peptide blocks. They are positioned to a great extent as tandem repeats of the sequence GAGAGS.

Aluminum alloy 3004 (Al-1.0 Mn-1.0 Mg) is the predominant material of choice for use in rigid beverage containers. The mechanical property requirements of the draw and iron forming operation dictate careful control of the aluminum sheet production parameters. The demand for ever lighter weight beverage containers has also continued to place increased demands on the strength requirements of the aluminum can stock. To achieve the strength requirements, the sheet must be produced in a highly cold-worked state. A practical consequence of this required level of cold work is pronounced mechanical and crystallographic anisotropy. Without careful control of can stock production parameters, pronounced rolling textures can lead to an undesirable directionality of properties that produce ears, formed during the deep drawing operation of can making, located 45° to the rolling direction. Figure 1 shows the rolling texture ears in a drawn and ironed beverage can.

This article illustrates the minimization and control of rolling texture earing in cold rolled 3004 alloy beverage can stock through modification of the fabricating process, application of metallurgical theory, optimization of hot rolling practice through empirical experimentation, and process control practices.