The main objective of this study is to perform nonlinear dynamic earthquake time history analyses on Morrow Point Dam, which is located 263 km southwest of Denver, Colorado. This project poses many significant technical challenges, one of which is to model the entire Morrow Point Dam/Foundation Rock/Reservoir system which includes accurate geology topography. In addition, the computational model must be initialized to represent the existing dead loads on the structure and the stress field caused by the dead loads. To achieve the correct dead load stress field due to gravity and hydrostatic load, the computer model must account for the manner in which the dams were constructed. Construction of a dam finite element model with the correct as-built geometry of the dam structure and simply ''turning on'' gravity in the computer model will generally lead to an incorrect initial stress field in the structure. The sequence of segmented lifts typical of dam construction has a significant impact on the static stress fields induced in the dam. In addition, the dam model must also account for the interaction between the adjacent dam segments across the dam contraction joints. As a result of these challenges, it was determined that a significant amount …

Although robotic machines are routinely used for welding, such machines do not normally incorporate intelligent capabilities. We are studying the general problem of formulating usable levels of intelligence into welding machines. From our perspective, an intelligent machine should: incorporate knowledge of the welding process, know if the process is operating correctly, know if the weld it is making is good or bad, have the ability to learn from its experience to perform welds, and be able to optimize its own performance. To this end, we are researching machine architecture, methods of knowledge representation, decision making and conflict resolution algorithms, methods of learning and optimization, human/machine interfaces, and various sensors. This paper presents work on the machine architecture and the human/machine interface specifically for a robotic, gas metal arc welding cell. Although the machine control problem is normally approached from the perspective of having a central body of control in the machine, we present a design using distributed agents. A prime goal of this work is to develop an architecture for an intelligent machine that will support a modular, plug and play standard. A secondary goal of this work is to formulate a human/machine interface that treats the human as an …

The Idaho National Engineering and Environmental Laboratory (INEEL), Nexant Inc. and the Oregon State University (OSU) have developed a Multi-Application Small Light Water Reactor (MASLWR) concept. The MASLWR is a small, safe and economic natural circulation pressurized light water reactor. MASLWR reactor module consists of an integral reactor/steam generator located in a steel cylindrical containment. The entire module is to be entirely shop fabricated and transported to site on most railways or roads. Two or more modules are located in a reactor building, each being submersed in a common, below grade cavity filled with water. For the most severe postulated accident, the volume of water in the cavity provides a passive ultimate heat sink for 3 or more days allowing the restoration of lost normal active heat removal systems. MASLWR thermal power of a single module is 150 MWt, primary system pressure 10.5 MPa, steam pressure1.52 MPa and the net electrical output is 35 - 50 MWe.

Utilization of surfactants for improved oil recovery (IOR) is an accepted technique with high potential. However, technology application is frequently limited by cost. Biosurfactants (surface-active molecules produced by microorganisms) are not widely utilized in the petroleum industry due to high production costs associated with use of expensive substrates and inefficient product recovery methods. The economics of biosurfactant production could be significantly impacted through use of media optimization and application of inexpensive carbon substrates such as agricultural process residuals. Utilization of biosurfactants produced from agricultural residuals may 1) result in an economic advantage for surfactant production and technology application, and 2) convert a substantial agricultural waste stream to a value-added product for IOR. A biosurfactant with high potential for use is surfactin, a lipopeptide biosurfactant, produced by Bacillus subtilis. Reported here is the production and potential IOR utilization of surfactin produced by Bacillus subtilis (American Type Culture Collection (ATCC) 21332) from starch-based media. Production of surfactants from microbiological growth media based on simple sugars, chemically pure starch medium, simulated liquid and solid potato-process effluent media, a commercially prepared potato starch in mineral salts, and process effluent from a potato processor is discussed. Additionally, the effect of chemical and physical pretreatments on …

The subsurface radioactive disposal site located at the Idaho National Engineering and Environmental Laboratory contains neutron-activated metals from nonfuel nuclear-reactor- core components. A long-term corrosion test is being conducted to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements in an arid vadose zone environment. The tests use nonradioactive metal coupons representing the prominent neutron-activated material buried at the disposal location, namely, Type 304L stainless steel, Type 315L stainless steel, nickel-chromium alloy (UNS NO7718), beryllium, aluminum 6061-T6, and a zirconium alloy, (UNS R60804). In addition, carbon steel (the material presently used in the cask disposal liners and other disposal containers) and a duplex stainless steel (UNS S32550) (the proposed material for the high- integrity disposal containers) are also included in the test program. This paper briefly describes the test program and presents the early corrosion rate results after 1 year and 3 years of underground exposure.

The evaluation of a release of radioactive material to the environment is a complex problem. The evaluation of the dose consequences from such a release adds issues that must be considered in order to determine the actual radiation dose to an individual. One of the key issues is the ingrowth of the progeny from the initial inventory during the transport through the environment. The evaluation of an acute release from a criticality accident and a chronic release of transuranics to the soil are the two extremes that demonstrate the spectrum of issues that must be addressed in order to determine the dose to a receptor at some distance and time from the release point. The evaluation of this can be accomplished by integration of the buildup and decay differential equations. The differential equations are difficult to evaluate for a source term that contains numerous short-lived radionuclides in decay chains. The evaluation is simplified by a method of evaluation called "counting atom". The source term is evaluated on an atom basis during production and transport. The life cycle of the atoms of each radionuclide are evaluated individually from the generation during a criticality event and during transport through the facility and …

A major feature of the Magnox gas cooled reactor design is the graphite core, which acts as the moderator but also provides the physical structure for fuel, control rods, instrumentation and coolant gas channels. The lifetime of a graphite core is dependent upon two principal aging processes: irradiation damage and radiolytic oxidation. Irradiation damage from fast neutrons creates lattice defects leading to changes in physical and mechanical properties and the accumulation of stresses. Radiolytic oxidation is caused by the reaction of oxidizing species from the carbon dioxide coolant gas with the graphite, these species being produced by gamma radiation. Radiolytic oxidation reduces the density and hence the moderating capability of the graphite, but also reduces strength affecting the integrity of core components. In order to manage continued operation over the planned lifetimes of their power stations, BNFL needed to extend their database of the effects of these two phenomena on their graphite cores through an irradiation experiment. This paper will discuss the background, purpose, and the processes taken and planned (i.e. post irradiation examination) to ensure meaningful data on the graphite core material is obtained from the irradiation experiment.

Silica and alkali metals in wheat straw limit its use for bioenergy and gasification. Slag deposits occur via the eutectic melting of SiO2 with K2O, trapping chlorides at surfaces and causing corrosion. A minimum melting point of 950°C is desirable, corresponding to SiO2:K2O of about 3:1. Mild chemical treatments were used to reduce Si, K, and Cl, while varying temperature, concentration, %-solids, and time. Dilute acid was more effective at removing K and Cl, while dilute alkali was more effective for Si. Reduction of minerals in this manner may prove economical for increasing utilization of the straw for combustion or gasification.

The California Climate Action Registry, which will begin operation in Fall 2002, is a voluntary registry for California businesses and organizations to record annual greenhouse gas emissions. Reporting of emissions in the Registry by a participant involves documentation of both ''direct'' emissions from sources that are under the entity's control and ''indirect'' emissions controlled by others. Electricity generated by an off-site power source is considered to be an indirect emission and must be included in the entity's report. Published electricity emissions factors for the State of California vary considerably due to differences in whether utility-owned out-of-state generation, non-utility generation, and electricity imports from other states are included. This paper describes the development of three methods for estimating electricity emissions factors for calculating the combined net carbon dioxide emissions from all generating facilities that provide electricity to Californians. We fi nd that use of a statewide average electricity emissions factor could drastically under- or over-estimate an entity's emissions due to the differences in generating resources among the utility service areas and seasonal variations. In addition, differentiating between marginal and average emissions is essential to accurately estimate the carbon dioxide savings from reducing electricity use. Results of this work will be taken …

Isotopically controlled silicon multilayer structures were used to measure the enhancement of self- and dopant diffusion in extrinsic boron doped silicon. {sup 30}Si was used as a tracer through a multilayer structure of alternating natural Si and enriched {sup 28}Si layers. Low energy, high resolution secondary ion mass spectrometry (SIMS) allowed for simultaneous measurement of self- and dopant diffusion profiles of samples annealed at temperatures between 850 C and 1100 C. A specially designed ion- implanted amorphous Si surface layer was used as a dopant source to suppress excess defects in the multilayer structure, thereby eliminating transient enhanced diffusion (TED) behavior. Self- and dopant diffusion coefficients, diffusion mechanisms, and native defect charge states were determined from computer-aided modeling, based on differential equations describing the diffusion processes. We present a quantitative description of B diffusion enhanced self-diffusion in silicon and conclude that the diffusion of both B and Si is mainly mediated by neutral and singly positively charged self-interstitials under p-type doping. No significant contribution of vacancies to either B or Si diffusion is observed.

Electron bunches produced in self-modulated laser wakefield experiments usually have a broad energy spectrum, with most electrons at low energy (1-3 MeV) and only a small fraction at high energy. We propose and investigate further acceleration of such bunches in a channel-guided resonant laser wakefield accelerator. Two-dimensional simulations with and without the effects of self-consistent beam loading are performed and compared. These results indicate that it is possible to trap about 40 percent of the injected bunch charge and accelerate this fraction to an average energy of about 50 MeV in a plasma channel of a few mn.

The role of moduli stabilization in predictions for CP violation is examined in the context of four-dimensional effective supergravity models obtained from the weakly coupled heterotic string. They point out that while stabilization of compactification moduli has been studied extensively, the determination of background values for other scalar by dynamical means has not been subjected to the same degree of scrutiny. These other complex scalars are important potential sources of CP violation and they show in a simple model how their background values (including complex phases) may be determined from the minimization of the supergravity scalar potential, subject to the constraint of vanishing cosmological constant.

We briefly discuss the predictions of the heavy quark effective theory for the semileptonic decays of a heavy pseudoscalar to a light one, or to a light vector meson. We point out that measurement of combinations of differential helicity decay rates at Cleo-c and the B factories can provide a model independent means of extracting the ratio |V{sub ub}|/|V{sub cd}|. We briefly discuss the corrections to this prediction.

Although human dentin is known to be susceptible to failure under repetitive cyclic fatigue loading, there are few reports in the literature that reliably quantify this phenomenon.

OAK A271 COMPOSITION AND STRUCTURAL STUDIES OF STRONG GLOW DISCHARGE POLYMER COATINGS. An investigation of the chemical composition and structure of strong glow discharge (GDP) polymer shells made for cryogenic experiments at OMEGA is described. The investigation was carried out using combustion and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The strongest coatings were observed to have the lowest hydrogen content or hydrogen/carbon H/C ratio, whereas the weakest coatings had the highest hydrogen content or H/C ratio. Chemical composition results from combustion were used to complement FTIR analysis to determine the relative hydrogen content of as-fabricated coatings. Good agreement was observed between composition results obtained from combustion and FTIR analysis. FTIR analysis of coating structures showed the strongest coatings to have less terminal methyl groups and a more double bond or olefinic structure. Strong GDP coatings that were aged in air react more with oxygen and moisture than standard GDP coatings. In addition to a more olefinic structure, there may also be more free-radial sites present in strong GDP coatings, which leads to greater oxygen uptake.

The extended Born, or localized nonlinear (LN) approximation, of integral equation (IE) solution has been applied to inverting single-hole electromagnetic (EM) data using a cylindrically symmetric model. The extended Born approximation is less accurate than a full solution but much superior to the simple Born approximation. When applied to the cylindrically symmetric model with a vertical magnetic dipole source, however, the accuracy of the extended Born approximation is shown to be greatly improved because the electric field is scalar and continuous everywhere. One of the most important steps in the inversion is the selection of a proper regularization parameter for stability. The extended Born solution provides an efficient means for selecting an optimum regularization parameter, because the Green's functions, the most time consuming part in IE methods, are repeatedly re-usable at each iteration. In addition, the IE formulation readily contains a sensitivity matrix, which can be revised at each iteration at little expense. In this paper we show inversion results using synthetic and field data. The result from field data is compared with that of a 3-D inversion scheme.

OAK A271 PRODUCTION OF HIGHER STRENGTH THIN WALLED GLOW DISCHARGE POLYMER SHELLS FOR CRYOGENIC EXPERIMENTS AT OMEGA. Thin walled polymer shells are needed for OMEGA cryogenic laser experiments. These capsules need to be about 900 {micro}m in diameter and as thin as possible (approx 1-2 {micro}m), while having enough strength to be filled with DT as fast as possible to about 1000 atm. The authors have found that by optimizing the coating parameters in the glow discharge polymer (GDP) deposition system, traditionally used for making ICF targets, they can routinely make robust, {approx} 1.5 {micro}m thick, 900 {micro}m diameter GDP shells with buckle strengths of over 0.3 atm. This is twice the strength of shells made prior to the optimization and is comparable to values quoted for polyimide shells. In addition, these shells were found to be approximately three times more permeable and over 20% denser than previously made GDP shells. The combination of higher strength and permeability is ideal for direct drive cryogenic targets at OMEGA. Shells as thin as 0.5 {micro}m have been made. In this paper, the authors discuss the shell fabrication process, effects of modifying various GDP deposition parameters on shell properties and chemical composition.

The transverse dynamics of a 28.5 GeV electron beam propagating in a 1.4 m long, 0-2 x 10{sup 14} cm{sup -3} plasma are studied experimentally in the underdense or blow-out regime. The transverse component of the wake field excited by the short electron bunch focuses the bunch, which experiences multiple betatron oscillations as the plasma density is increased. The spot size variations are observed using optical transition radiation and Cherenkov radiation. In this regime, the behavior of the spot size as a function of the plasma density is well described by a simple beam envelope model. Dynamic changes of the beam envelope are observed by time resolving the Cherenkov light.

Motivated by recent experimental indications of large {nu}{sub {mu}} - {nu}{tau} mixing, we explore current bounds on the analogous mixing in the charged lepton sector. We present a general formalism for dimension-6 fermionic effective operators involving {tau}-{mu} mixing with typical Lorentz structures and discuss their relationship to the standard model gauge symmetry. We find the low-energy constraints on the new physics scale associated with each operator, mostly from current experimental bounds on rare decay processes of {tau}, hadrons or heavy quarks. For operators involving at least one light quark (u, d, s), these constraints typically give a bound on the new physics scale of a few TeV or higher. Those operators with two heavy quarks turn out to be more weakly constrained at present, giving bounds of a few hundred GeV. A few scalar and pseudo-scalar operators are not subject to any current experimental constraints.

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An introductory review of generalized parton distributions (GPDs) is given. The structure of hadrons is the fundamental physics to be accessed via GPDs. GPDs describe hadronic structure on the quark-gluon level and provide a 3-dimensional picture (''tomography'') of hadronic structure. GPDs adequately reflect the quantum-field nature of QCD (correlations, interference). They also provide new insights into spin structure of hadrons (spin-flip distributions, orbital angular momentum). GPDs are sensitive to chiral symmetry breaking effects, a fundamental property of QCD. Furthermore, GPDs unify existing ways of describing hadronic structure. The GPD formalism provides nontrivial relations between different exclusive reactions and also between exclusive and inclusive processes.

A new generation of experiments for studies of the nucleon structure with electromagnetic probes is under consideration by the physics community interested in hadron physics. One of the main goals of these projects is studying the Generalized Parton Distributions (GPD), which typically requires detecting several particles in the final state, high luminosity, large acceptance and good missing mass resolution of the spectrometers. The combination of these requirements is challenging and pushes the detectors involved to the limits. In this paper a review of the proposed experiments is presented and their feasibility is evaluated taking into account the recent progress of the detector technique.

Nonperturbative and perturbative interaction mechanisms of Wilson loops in gluodynamics are studied within the background field formalism. The first one operates when distance between minimal surfaces of the loops is small and may be important for sea quark effects and strong decay processes. The second mechanism -- perturbative interaction in nonperturbative confining background is found to be physically dominant for all loop configurations characteristic of scattering process. It reduces to perturbative gluon exchanges at small distances, while at larger distances it corresponds to the t-channel exchange of (reggeized) glueball states. Comparison to other approaches is made and possible physical applications are discussed.

An overview of recent measurements of the neutron and proton electromagnetic form factors from double polarization experiments. Spin observables are sensitive to the product of nucleon form factor which allows access to the small nucleon electric form factors.