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In this paper, the authors theoretically predict the best efficient way for electromagnetic wave emission by Josephson plasma excitation in intrinsic Josephson junctions. First, they briefly derive basic equations describing dynamics of phase differences inside junction sites in intrinsic Josephson junctions, and review the nature of Josephson plasma excitation modes based on the equations. Especially, they make an attention to that Josephson plasma modes have much different dispersion relations depending on the propagating directions and their different modes can be recognized as N standing waves propagating along ah-plane in cases of finite stacked systems composed of N junctions. Second, they consider how to excite their modes and point out that excitations of in-phase mode with the highest propagation velocity among their N modes are the most efficient way for electromagnetic wave emissions. Finally, they clarify that in-phase excitations over all junctions are possible by using Josephson vortex flow states. They show simulation results of Josephson vortex flow states resonating with some Josephson plasma modes and predict that superradiance of electromagnetic field may occur in rectangular vortex flow state in which spatiotemporal oscillations of electromagnetic fields are perfectly in-phase.

This study examined cesium ({sup 137}Cs) ion exchange of crystalline silicotitanate (CST) in simulated waste solution. In particular, the study focused on the effect of CST pretreatment on the kinetics and extent of cesium adsorption. The test used IONSIV{reg_sign}IE-911 (UOP LLC, Molecular Sieves Division, Des Plaines, IL), the engineered form of CST. Pretreatment steps examined include: soaking CST in 2M NaOH solution for three days, exposing CST to 50% relative humidity for one week, flowing organic-containing (saturated) salt solution through a CST packed bed (at 5 cm/min. superficial velocity), or drying CST in air at 100 C for three days. Some tests occurred under 50 and 25 psig of argon. The following conclusions summarize the results. Pretreatment of IE-911 in organic-containing (e.g., tri-n-butyl phosphate, dibutylphosphate, butanol, paraffin and Dow Corning H-10 defoamer) simulated waste or simulated waste yielded a 83% slower rate of cesium adsorption and 56% lower cesium capacity after one week. Pretreatment of IE-911 in 2M caustic solution for 48 hours yielded a slower approach to equilibrium cesium distribution in batch contact tests--7.7 mL/(g*h) during the first 48 hours and 2.4 ml/(g*h) thereafter. Carboxylates and adsorbed carbonates inside the pores likely affect the cesium transport by either increasing …

Understanding the properties of high gain (alpha-dominated) fusion plasmas in an advanced toroidal configuration is the largest remaining open issue that must be addressed to provide the scientific foundation for an attractive magnetic fusion reactor. The critical parts of this science can be obtained in a compact high field tokamak which is also likely to provide the fastest and least expensive path to understanding alpha-dominated plasmas in advanced toroidal systems.

Recent CDF results in inclusive momentum distributions and multiplicities of particles in restricted cones around jets are compared to predictions using the Modified Leading Log Approximation. The authors found that MLLA gives a very reasonable description of jet fragmentation for a wide range of energies. Model parameters are extracted separately from the multiplicity and from the shape of the momentum distributions and are found to agree. The ratio of charged particle multiplicities in the gluon and quark jets measured in the context of MLLA is compared to the model-independent result and also found to agree.

Robocasting, a computer controlled slurry deposition technique, was used to fabricate ceramic monoliths and composites of chemically prepared Pb(Zr{sub 0.95}Ti{sub 0.05})O{sub 3} (PZT 95/5) ceramics. Densities and electrical properties of the robocast samples were equivalent to those obtained for cold isostatically pressed (CIP) parts formed at 200 MPa. Robocast composites consisting of alternate layers of the following sintered densities: (93.9%--96.1%--93.9%), were fabricated using different levels of organic pore former additions. Modification from a single to a multiple material deposition robocaster was essential to the fabrication of composites that could withstand repeated cycles of saturated polarization switching under 30 kV/cm fields. Further, these composites withstood 500 MPa hydrostatic pressure induced poled ferroelectric (FE) to antiferroelectric (AFE) phase transformation during which strain differences on the order of 0.8% occurred between composite elements.

We present a computational method that finds an efficient runner network for an investment casting, once the gate locations have been established. The method seeks to minimize a cost function that is based on total network volume. The runner segments are restricted to lie in the space not occupied by the part itself. The collection of algorithms has been coded in C and runner designs have been computed for several real parts, demonstrating substantial reductions in rigging volume.

Some clusters of galaxies have been identified as powerful sources of non-thermal radiation, from the radio to X-ray wavelengths. The classical models proposed for the explanation of this radiation usually require large energy densities in cosmic rays in the intracluster medium and magnetic fields much lower than those measured using the Faraday rotation. They study here the role that mergers of clusters of galaxies may play in the generation of the non-thermal radiation, and they seek for additional observable consequences of the model. They find that if hard X-rays and radio radiation are respectively interpreted as inverse Compton scattering (ICS) and synchrotron emission of relativistic electrons, large gamma ray fluxes are produced, and for the Coma cluster, where upper limits are available, these limits are exceeded. They also discuss an alternative and testable model that naturally solves the problems mentioned above.

The Inventions and Innovation Program, formerly known as ERIP (Energy-related Inventions Program), was established by the U.S. Congress in 1974. The program offers assistance to independent inventors and very small businesses engaged in developing new energy-saving technologies. The program remains clearly focused on energy generation and savings. The I&I Program funding is based on a competitive proposal process.

Proton-antiproton collisions at the Fermilab Tevatron collider currently offer the highest energy collisions available in the laboratory. In this paper the authors briefly discuss measurements which are sensitive to the internal structure of the proton. They also describe measurements which search for substructure in the partons, the quarks and gluons which form the proton.

The influence of the substrate on the translational and orientational ordering in sub-monolayer films of passivated multiply-twinned gold clusters has been investigated using high resolution and dark field transmission electron microscopy. Although clear differences were observed in the degree of translational ordering on amorphous carbon and etched silicon substrates, there was no corresponding variation in the crystallographic orientation of the nanocrystal cores. The results demonstrate that the orientation of passivated clusters with multiply-twinned cores is effectively random with respect to both the superlattice and the substrate.

During the past several decades magnetic fusion has made outstanding progress in understanding the science of fusion plasmas, the achievement of actual fusion plasmas and the development of key fusion technologies. Magnetic fusion is now technically ready to take the next step: the study of high gain fusion plasmas, the optimization of fusion plasmas and the continued development and integration of fusion technology. However, each of these objectives requires significant resources since the tests are now being done at the energy production scale. This paper describes a modular approach that addresses these objectives in specialized facilities that reduces the technical risk and lowers cost for near term facilities needed to address critical issues.

Hydrogen storage for mobile applications is still a challenge. Savannah River Technology Center (SRTC) and its partners have identified industrial utility vehicles and mining vehicles as potential early niche markets for the use of metal hydride to store hydrogen. The weight of metal hydride is not a problem for these vehicles. The low pressure of metal hydride gives a safety advantage. SRTC has developed onboard hydrogen storage containers using metal hydrides for the demonstration of two generations of fuel cell powered utility vehicles. Another storage container is being developed for a mining vehicle. This paper provides a brief overview of the utility vehicle project and a detail discussion of the hydrogen storage system.

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The ability to engineer ordered arrays of objects on multiple length scales has potential for applications such as microelectronics, sensors, wave guides, and photonic lattices with tunable band gaps. Since the invention of surfactant templated mesoporous sieves in 1992, great progress has been made in controlling different mesophases in the form of powders, particles, fibers, and films. To date, although there have been several reports of patterned mesostructures, materials prepared have been limited to metal oxides with no specific functionality. For many of the envisioned applications of hierarchical materials in micro-systems, sensors, waveguides, photonics, and electronics, it is necessary to define both form and function on several length scales. In addition, the patterning strategies utilized so far require hours or even days for completion. Such slow processes are inherently difficult to implement in commercial environments. The authors present a series of new methods of producing patterns within seconds. Combining sol-gel chemistry, Evaporation-Induced Self-Assembly (EISA), and rapid prototyping techniques like pen lithography, ink-jet printing, and dip-coating on micro-contact printed substrates, they form hierarchically organized silica structures that exhibit order and function on multiple scales: on the molecular scale, functional organic moieties are positioned on pore surfaces, on the mesoscale, mono-sized pores …

Computer models of the performance of heat pumps and of individual components are described; preliminary results from system improvement studies using these models are presented. The system model which is based on the underlying physical principles, rather than empirical data, uses a calculational scheme used previously by Hiller and Glicksman. It is generalized so that it may be used to calculate performance and efficiency over a broad range of operating conditions. Its intended use is the investigation of changes in system performance brought about by,modifications of the individual components, and to aid in gaining detailed understanding of the interactions between components. Examples of predicted improvements in performance based on the use of these programs are presented. New heat exchanger models, based on a tube-by-tube computational approach, may be used by the system model when appropriate. In these models, the thermal and fluid flow performance of each tube in the heat exchanger is computed individually using local temperatures and heat transfer coefficients. Tube circuiting sequences may be specified by the user, the joining or branching of parallel refrigerant circuits is accommodated, and appropriate mixing expressions are used. Air-side correlations for any surface geometry may be specified. Comparison of calculated and observed …

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As part of the U.S. Department of Energy/Electric Power Research Institute (DOE-EPRI) Wind Turbine Verification Program (TVP), tests are conducted to characterize the power performance of individual wind turbines at each wind project. The testing is performed in a variety of terrain types, including mountains, plains, deserts, and coastal tundra; and under a wide range of atmospheric conditions, from arid to arctic. Initial results and experiences of the testing were reported the WindPower 2000 conference. This paper presents the status of the power performance testing and new results from the past year.

In the authors initial high heat flux tests on small mockups armored with W rods, done in the small electron beam facility (EBTS) at Sandia National Laboratories, the mockups exhibited excellent thermal performance. However, to reach high heat fluxes, they reduced the heated area to only a portion ({approximately}25%) of the sample. They have now begun tests in their larger electron beam facility, EB 1200, where the available power (1.2 MW) is more than enough to heat the entire surface area of the small mockups. The initial results indicate that, at a given power, the surface temperatures of rods in the EB 1200 tests is somewhat higher than was observed in the EBTS tests. Also, it appears that one mockup (PW-10) has higher surface temperatures than other mockups with similar height (10mm) W rods, and that the previously reported values of absorbed heat flux on this mockup were too high. In the tests in EB 1200 of a second mockup, PW-4, absorbed heat fluxes of {approximately}22MW/m{sup 2} were reached but the corresponding surface temperatures were somewhat higher than in EBTS. A further conclusion is that the simple 1-D model initially used in evaluating some of the results from the EBTS …

In May 1985, a National Pollutant Discharge Elimination System (NPDES) permit was issued for the Oak Ridge Y-12 Plant. As a condition of the permit, a Biological Monitoring and Abatement Program (BMAP) was developed to demonstrate that the effluent limitations established for the Y-12 Plant protect the classified uses of the receiving stream (East Fork Poplar Creek; EFPC), in particular, the growth and propagation of aquatic life (Loar et al. 1989). A second objective of the BMAP is to document the ecological effects resulting from the implementation of a water pollution control program designed to eliminate direct discharges of wastewaters to EFPC and to minimize the inadvertent release of pollutants to the environment. Because of the complex nature of the discharges to EFPC and the temporal and spatial variability in the composition of the discharges, a comprehensive, integrated approach to biological monitoring was developed. A new permit was issued to the Y-12 Plant on April 28, 1995 and became effective on July 1, 1995. Biological monitoring continues to be required under the new permit. The BMAP consists of four major tasks that reflect different but complementary approaches to evaluating the effects of the Y-12 Plant discharges on the aquatic integrity …

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This paper describes the most recent version of a human reliability analysis (HRA) method called ``A Technique for Human Event Analysis'' (ATHEANA). The new version is documented in NUREG-1624, Rev. 1 [1] and reflects improvements to the method based on comments received from a peer review that was held in 1998 (see [2] for a detailed discussion of the peer review comments) and on the results of an initial trial application of the method conducted at a nuclear power plant in 1997 (see Appendix A in [3]). A summary of the more important recommendations resulting from the peer review and trial application is provided and critical and unique aspects of the revised method are discussed.