Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen or ambient-temperature compressed hydrogen. This flexibility results in multiple advantages with respect to compressed hydrogen tanks or low-pressure liquid hydrogen tanks. Our work is directed at verifying that commercially available aluminum-lined, fiber-wrapped pressure vessels can be safely used to store liquid hydrogen. A series of tests have been conducted, and the results indicate that no significant vessel damage has resulted from cryogenic operation. Future activities include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for certification of insulated pressure vessels.

The Source Injector Program for the US Heavy Ion Fusion Virtual National Laboratory is currently exploring the feasibility of using RF gas plasma sources for a HIF driver. This source technology is presently the leading candidate for the multiple aperture concept, in which bright millimeter size beamlets are extracted and accelerated electrostatically up to 1 MeV before the beamlets are allowed to merge and form 1 A beams. Initial experiments have successfully demonstrated simultaneously high current density, {approx} 100 mA/cm{sup 2} and fast turn on, {approx} 1 {micro}s. These experiments were also used to explore operating ranges for pressure and RF power. Results from these experiments are presented as well as progress and plans for the next set of experiments for these sources.

In oxidizing environments, the toxic and radioactive element uranium is most soluble and mobile in the hexavalent oxidation state. These processes also affect the biological availability of U(VI) species toward reduction and precipitation as the less soluble U(IV) species by metal-reducing bacteria. The results provide compelling evidence of U incorporation within the hematite structure.

To enable collaboration on the daily tasks involved in scientific research, collaborative frameworks should provide lightweight and ubiquitous components that support a wide variety of interaction modes. We envision a collaborative environment as one that provides a persistent space within which participants can locate each other, exchange synchronous and asynchronous messages, share documents and applications, share workflow, and hold videoconferences. We are developing the Pervasive Collaborative Computing Environment (PCCE) as such an environment. The PCCE will provide integrated tools to support shared computing and task control and monitoring. This paper describes the PCCE and the rationale for its design.

Several technologies are being developed to convert coal into clean fuel for use in power generation. From the standpoint of component materials in these technologies, the environments created by coal conversion and their interactions with materials are of interest. Coal is a complex and relatively dirty fuel that contains varying amounts of sulfur and a substantial fraction of noncombustible mineral constituents, commonly called ash. Corrosion of metallic and ceramic structural materials is a potential problem at elevated temperatures in the presence of complex gas environments and coal-derived solid/liquid deposits. This paper discusses the coal-fired systems currently under development, identifies several modes of corrosion degradation that occur in many of these systems, and suggests possible mechanisms of metal wastage. Available data on the performance of materials in some of the environments are highlighted, and the research needed to improve the corrosion resistance of various materials is presented.

The First Community Consultation on the Responsible Collection and Use of Samples for Genetic Research was held in Bethesda, Maryland, on September 25-26, 2000. The consultation was convened by the National Institute of General Medical Sciences (NIGMS) of the National Institutes of Health (NIH). Approximately 120 individuals participated in the consultation, half from a broad range of communities and populations, and half from government. The participants shared their views and concerns about population- and community-based genetic research, expanding the focus of the meeting from the collection and use of blood or other tissue samples for genetic research to broader issues and concerns about the conduct of genetic research in general with populations and communities.

We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure.

The microstructure of materials, i.e. the size, shape and arrangement of grains, determines essentially the material properties such as mechanical strength, toughness, electrical conductivity and magnetic susceptibility. In general the desirable property of materials can be controlled and improved by understanding of microstructure evolution processes in grain growth controlled by grain boundary migration, and grain boundary diffusion. The process of grain growth involves both grain boundary migration (moving interfaces) and topological changes of grain boundary geometry, and it can not be effectively modeled by Lagrangian, Eulerian, or Arbitrary Lagrangian Eulerian finite element method when in addition the stress effect is considered. A double-grid method is proposed for modeling grain boundary migration under stress. In this approach, the material grid carries kinematic and kinetic material variables, whereas the grain boundary grid carries only grain boundary kinematic variables. The material domain is discretized by a reproducing kernel approximation with strain discontinuity enrichment across the grain boundaries. The grain boundaries, on the other hand, are discretized by the standard finite elements. This approach allows modeling of arbitrary evolution of grain boundaries without remeshing.

A materials test program was developed to measure mechanical properties of ASTM A285 Grade B low carbon steel for application to structural and flaw stability analysis of storage tanks at the Department of Energy (DOE) Savannah River Site (SRS). Under this plan, fracture toughness and tensile testing are being performed at conditions that are representative of storage tank

EUV mask blanks are fabricated by depositing a reflective Mo/Si multilayer film onto super-polished substrates. Small defects in this thin film coating can significantly alter the reflected field and introduce defects in the printed image. Ideally one would want to produce defect-free mask blanks; however, this may be very difficult to achieve in practice. One practical way to increase the yield of mask blanks is to effectively repair multilayer defects, and to this effect they present two complementary defect repair strategies for use on multilayer-coated EUVL mask blanks. A defect is any area on the mask which causes unwanted variations in EUV dose in the aerial image obtained in a printing tool, and defect repair is correspondingly defined as any strategy that renders a defect unprintable during exposure. The term defect mitigation can be adopted to describe any strategy which renders a critical defect non-critical when printed, and in this regard a non-critical defect is one that does not adversely affect device function. Defects in the patterned absorber layer consist of regions where metal, typically chrome, is unintentionally added or removed from the pattern leading to errors in the reflected field. There currently exists a mature technology based on ion …

We are working on developing an alternative technology for storage of hydrogen or natural gas on light-duty vehicles. This technology has been titled insulated pressure vessels. Insulated pressure vessels are cryogenic-capable pressure vessels that can accept either liquid fuel or ambient-temperature compressed fuel. Insulated pressure vessels offer the advantages of cryogenic liquid fuel tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for fuel liquefaction and reduced evaporative losses). The work described in this paper is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen or LNG. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Future activities include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining insulated pressure vessel certification.

Lead-Bismuth Eutectic is under consideration as a target material with high-energy protons for generating spallation neutrons to operate actinide and fission product transmuters. An assessment has been performed to study the performance of this target material as a function of the main variables and the design selections. The assessment includes the neutron yield, the spatial energy deposition, the neutron spectrum, the beam window performance, and the target buffer requirements. Heat transfer, hydraulics, beam window material and stresses, and target engineering issues have been considered. The assessment has also considered high-energy deuteron particles to study the impact on the target performance.

From the experiments performed it is possible to determine a wide range of information about the metallurgy of the astrolabes studied. It was found that different brass alloys were used for components that were cast and those that were mechanically deformed. Chemical composition, forming history, and thickness measurements are all determined non-destructively, illustrating that this technique could be useful for many applications with metal artifact analysis where non-intrusive methods are required.