A mechanism to finely align optics for extreme ultraviolet lithography applications is presented. The mechanism is a small motion parallel link manipulator with flexure joints that exhibits nanometer level positioning capability. Performance results of a prototype system are given in this paper.

The combined role of inelastic scattering with nucleons and comoving secondary particles in J/{psi} suppression is explored. An analysis of the latest FNAL and CERN data suggests that the high-density comover contribution emerges with increasing incident energy and A.

The Fabry Perot has become an important and valuable tool by which explosive performance information can be obtained relatively easily and inexpensively. Principle uses of the Fabry Perot have been free surface, and particle velocity measurements in one dimensional studies of explosive performance. In the cylinder test, it has been very useful to resolve early wall motions. We have refined methods of characterizing new explosives i.e. equation of state, C-J pressure, via the cylinder shot, flat plate, and particle velocity techniques. All of these use Fabry Perot as one of the principle diagnostics. Each of these experimental techniques are discussed briefly and some of the results obtained. Modeling developed to fit Fabry-Perot results are described along with future testing.

A polarized target of ethylamine + borane-ammonia + EHBA-Cr(V) was exposed to an integrated beam flux of 10/sup 14/cm/sup 2/. The polarization is shown as a function of proton irradiation. (DLC)

The U. S. Air Force Advanced Electro-Optical System (AEOS) which includes a 941 actuator adaptive optics system on a 3.7m telescope has recently been made available for astronomical programs. Operating at a wavelength of 750 nm, the diffraction-limited angular resolution of the system is 0.04 inches; currently, the magnitude limit is V {approx} 7 mag. At the distances of nearby open clusters, diffraction-limited images should resolve companions with separations as small as 4-6 AU--comparable to the Sun-Jupiter distance. The ability to study such close separations is critical, since most companions are expected to have separations in the few AU to tens of AU range. With the exceptional angular resolution of the current AEOS setup, but restricted target magnitude range, we are conducting a companion search of a large, well-defined sample of bright early-type stars in nearby open clusters and in the field. Our data set will both characterize this relatively new adaptive optics system and answer questions in binary star formation and stellar X-ray activity. We will discuss our experience using AEOS, the data analysis involved, and our initial results.

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ITER diagnostic port plugs perform many functionsincluding structural support of diagnostic systems under high electromagnetic loads while allowing for diagnostic access to the plasma. The design of diagnostic equatorial port plugs (EPP) are largely driven by electromagnetic loads and associate responses of EPP structure during plasma disruptions and VDEs. This paper summarizes results of transient electromagnetic analysis using Opera 3d in support of the design activities for ITER diagnostic EPP. A complete distribution of disruption loads on the Diagnostic First Walls (DFWs), Diagnostic Shield Modules (DSMs) and the EPP structure, as well as impact on the system design integration due to electrical contact among various EPP structural components are discussed.

The authors have developed tools for the efficient preparation of CAD geometries for mesh generation. Geometries are read from IGES files and then maintained in a boundary-representation consisting of a patchwork of trimmed and untrimmed surfaces. Gross errors in the geometry can be identified and removed automatically while a user interface is provided for manipulating the geometry (such as correcting invalid trimming curves or removing unwanted details). Modifying the geometry by adding or deleting surfaces and/or sectioning it by arbitrary planes (e.g. symmetry planes) is also supported. These tools are used for robust and accurate geometry models for initial mesh generation and will be applied to in situ mesh generation requirements of moving and adaptive grid simulations.

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A fusion pilot plant study was initiated to clarify the development needs in moving from ITER to a first of a kind fusion power plant, following a path similar to the approach adopted for the commercialization of fission. The pilot plant mission encompassed component test and fusion nuclear science missions plus the requirement to produce net electricity with high availability in a device designed to be prototypical of the commercial device. Three magnetic configuration options were developed around this mission: the advanced tokamak (AT), spherical tokamak (ST) and compact stellarator (CS). With the completion of the study and separate documentation of each design option a question can now be posed; how do the different designs compare with each other as candidates for meeting the pilot plant mission? In a pro/con format this paper will examine the key arguments for and against the AT, ST and CS magnetic configurations. Key topics addressed include: plasma parameters, device configurations, size and weight comparisons, diagnostic issues, maintenance schemes, availability influences and possible test cell arrangement schemes.

The NSTX upgrade project requires analysis qualifications of existing vacuum vessel and passive stabilizing plates for increased plasma performance. Vertical stability is critically dependent on the passive conducting structure that surrounds the plasma. In this paper, the passive conducting structure is analyzed for the upgrade condition during plasma disruption to ensure the level of stress in the stabilizing plates and the fastener is within its design limits. The counter-bore of the passive plates for bolting is evaluated in details and counter-bore bushing is redesigned to prevent shear failure during disruptions as a result of high pulling and pushing forces, particularly for support at the corner bolts

In information theory, a signature is characterized by the information content as well as noise statistics of the communication channel. Biosignatures have analogous properties. A biosignature can be associated with a particular attribute of a pathogen or a host. However, the signature may be lost in backgrounds of similar or even identical signals from other sources. In this paper, we highlight statistical and signal processing challenges associated with identifying good biosignatures for pathogens in host and other environments. In some cases it may be possible to identify useful signatures of pathogens through indirect but amplified signals from the host. Discovery of these signatures requires new approaches to modeling and data interpretation. For environmental biosignal collections, it is possible to use signal processing techniques from other applications (e.g., synthetic aperture radar) to track the natural progression of microbes over large areas. We also present a computer-assisted approach to identify unique nucleic-acid based microbial signatures. Finally, an understanding of host-pathogen interactions will result in better detectors as well as opportunities in vaccines and therapeutics.

In the National Ignition Facility (NIF) ICF point design, the cylindrical hohlraum target is illuminated by multiple laser beams through two laser entrance holes on the ends. According to simulations by LASNEX and HYDRA plasma created inside the hohlraum will stream out of the LEH, accelerate to supersonic speeds and then fan out radially. Inside the hohlraum, flows are subsonic. Forward Brillouin scattering can transfer energy between pairs of laser beams (0 and 1) if the following frequency matching condition is satisfied: {omega}{sub 0} - {omega}{sub 1} = (k{sub 0} - k{sub 1}) {center_dot} V + |k{sub 0} - k{sub 1}| c{sub s} (1) where {omega}{sub 0.1} and k{sub 0.1} are the frequencies and wave-numbers of the two laser beams, V is the plasma flow velocity and c{sub s} is the local ion sound speed. In the nominal case of equal frequency beams, this requires the component of the plasma flow velocity transverse to the bisector of the beam directions to be sonic, with the resulting transfer being to the downstream beam. In the NIF beam geometry, this is from the outer to inner cones of beams. The physics of this transfer is the same as in beam bending; the …

The Moving Least Squares (MLS) grid-free method, a simple, flexible finite difference method for solution of general continuum mechanics problems, especially detonation problems, is proposed in this paper. The spatial points that carry time dependent data are distributed in space in such a way that provides nearly uniform spacing of points, accurate presentation of boundaries, easy variation of resolution and arbitrary reorganization of the computational domain. Local finite difference operators are obtained with simple MLS differentiation. There is no specific topological or geometrical restriction of the distribution of data points. Therefore this method avoids many drawbacks of the traditional methods. Because of its flexibility, it can be used to simulate a wide range of mechanics problems. Because of its simplicity, it has the potential to become a preferred method. Most traditional computational continuum mechanics (CCM) methods, from a Smooth Particle Hydrodynamics (SPH) view, can be considered as special cases of grid-free methods of specific kernel functions. Such a generalization allows the development of a unified grid-free method that can represent most finite difference methods by switching the kernel functions. The flexible management and ease of coding make such a unified code attractive for many applications. A simple three-dimensional narrow-band level-set …

The electrical discharge techniques, called non-thermal, utilize high voltage breakdown of gases using short pulses of one to a few hundred nanoseconds. These short pulses between metal electrodes generate energetic electrons without appreciable thermal heating of the gas. The energetic electrons collide with gas molecules to form radicals. The radicals then react with pollutants to form harmless compounds. Our experimental device uses a wire in a pipe geometry. The wire is driven by a 40 kilovolt pulse 100 nanoseconds long. Gas is circulated in a loop through the pipe geometry in a closed system. This system permits the introduction of various gas combinations prior to testing. The recirculated gas can be heated to determine the effect on the electrical discharge, and chemical reactions. The efficiency of pollutant removal is the key to applications. We have been able to significantly improve the efficiency of NO removal by the addition of hydrocarbons. Nitric oxide has been removed with an energy cost of 15 ev per NO molecule. We believe the hydrocarbon additive serves by recycling the hydroxyl radicals during the oxidation and reduction of NO. The implementation of this process will depend largely on how much additives, electrical power consumption, and final …

This article reports the first effort to assess the impact of land-use change on soil diversity for the entire nation of China.

This article characterizes the infinitesimal generators of semigroups of linear transformations.

This article is an editorial on the research topic Microbial C1 Metabolism and Biotechnology. This special topic presents studies focused on the fundamental aspects of C1 metabolism in diverse microbial systems with the ability to convert anthropogenic greenhouse gases into valuable products.

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