I am pleased to present the CFO's FY06 Financial Report for Sandia National Laboratories (SNL). As a contractor to DOE and other government agencies, the bulk of SNL's revenue is from tax dollars. SNL's FY06 total revenue, total expenditures, and total employment levels were slightly below the FY05 record high levels. Throughout FY06, SNL business staff continued to improve SNL's financial stewardship of entrusted taxpayer funds through implementation of best-in-class practices in financial business operations and internal control policies and procedures to ensure compliance with all accounting standards and provide accountability to our customers. Our FY06 efforts focused on process certification and improvement, implementing OMB Circular A-123, achieving assurance activities, implementation of a Financial Management Competency Program throughout SNL, and continuous assessment of trends and emerging issues.
The annual program report provides detailed information about all aspects of the Sandia National Laboratories, California (SNL/CA) Environmental Planning and Ecology Program for a given calendar year. It functions as supporting documentation to the SNL/CA Environmental Management System Program Manual. The 2006 program report describes the activities undertaken during the past year, and activities planned in future years to implement the Planning and Ecology Program, one of six programs that supports environmental management at SNL/CA.
Fan, Yuan; Chen, Qian; Ayres, Virginia M.; Baczewski, Andrew D.; Udpa, Lalita; Kumar, Shiva
Scanning probe recognition microscopy is a new scanning probe microscopy technique which enables selective scanning along individual nanofibers within a tissue scaffold. Statistically significant data for multiple properties can be collected by repetitively fine-scanning an identical region of interest. The results of a scanning probe recognition microscopy investigation of the surface roughness and elasticity of a series of tissue scaffolds are presented. Deconvolution and statistical methods were developed and used for data accuracy along curved nanofiber surfaces. Furthermore, nanofiber features were also independently analyzed using transmission electron microscopy, with results that supported the scanning probe recognition microscopy-based analysis.
By far the most widely used tool in shock data analysis is the shock response spectrum (SRS). The SRS has gained popularity because of several primary considerations. It has physical significance, it is simple to understand and it is believed to indicate shock severity. Despite its popularity, the SRS has limitations. Foremost among them is the underlying assumption that shock severity is proportional to a time derivative of position, which does not agree with accepted material failure models. Also, the SRS cannot distinguish between naturally occurring, complex shocks and the chirps sometimes used to achieve a desired SRS using electrodynamic shakers with inadequate force capabilities. Thirdly, SODF models used in the computation of the SRS do not accurately predict accelerations in MDOF structures. A relatively new concept has been introduced whereby an analysis is made on the work done on structures by the excitation force. Since work is equal to the change in the energy of a system, this quantity is closely related to failure models based on strain energy such as the Von Mesis criterion. This paper is the first in a series exploring the use of energy-based description of shock motion and structural response. The input energy spectrum has attractive properties which include intuitive physical significance, insensitivity to system parameters such as viscous damping or hysteretic loss, the ability to distinguish between realistic shocks and chirps, and a close relation to accepted material failure models. Input energy spectra can be calculated using SDOF models and, in many cases, accurately predict the energy input to MDOF structures. Finally, this paper gives an introduction to these methods, derives the equations for relevant energy measures and presents relationships to several other shock analysis tools.
We report on algebraic multilevel preconditioners for the parallel solution of linear systems arising from a Newton procedure applied to the finite-element (FE) discretization of the incompressible Navier-Stokes equations. We focus on the issue of how to coarsen FE operators produced from high aspect ratio elements.
The focus of this paper is a penalty-based strategy for preconditioning elliptic saddle point systems. As the starting point, we consider the regularization approach of Axelsson in which a related linear system, differing only in the (2,2) block of the coefficient matrix, is introduced. By choosing this block to be negative definite, the dual unknowns of the related system can be eliminated resulting in a positive definite primal Schur complement. Rather than solving the Schur complement system exactly, an approximate solution is obtained using a substructuring preconditioner. The approximate primal solution together with the recovered dual solution then define the preconditioned residual for the original system.
The effect of exhaust-gas recirculation (EGR) on the equivalence ratio of premixed-burn mixture in diesel combustion was investigated experimentally. The ambient oxygen concentration was systematically decreased from 21% to 10% in a constant-volume combustion vessel to simulate EGR effects in engines. Pressure measurements and time-resolved imaging of high-temperature chemiluminescence were used to characterize the temporal and spatial ignition and premixed burn characteristics of n-heptane diesel jets. With increasing EGR, ignition delay increases and the location of premixed burn occurs further down-stream from the nozzle. Subsequent to first ignition, high temperature reactions stabilize at a quasi-steady lift-off length, showing that lift-off is a bounding parameter for determining premixed-burn region. The equivalence ratio of the fuel-ambient mixture in the premixed-burn region was measured using planar laser Rayleigh scattering. Fuel-oxygen mass distribution functions show that more mass is mixed into the premixed-burn region with increasing EGR, but the equivalence ratio of this mixture is the same. The study shows that an increasing ignition delay with increasing EGR does not necessarily decrease the equivalence ratio as would be desired for reducing soot formation in low-temperature combustion engines. However, measures to improve fuel-ambient mixing, such as shortened injection durations coupled to long ignition delay, could decrease equivalence ratio.
One-dimensional (1-D) line Rayleigh thermometry is used to investigate the effects of spatial resolution and noise on thermal dissipation in turbulent non-premixed CH4/H2/N2 jet flames. The high signal-tonoise ratio and spatial resolution of the measured temperature field enables determination of the cutoff wavenumber in the 1-D temperature dissipation spectrum obtained at each flame location. The local scale inferred from this cutoff is analogous to the Batchelor scale in nonreacting flows. At downstream locations in the flames studied here, it is consistent with estimates of the Batchelor scale based on the scaling laws using local Reynolds numbers. The spectral cutoff information is used to design data analysis schemes for determining mean thermal dissipation. Laminar flame measurements are used to characterize experimental noise and correct for the noise-induced apparent dissipation in the turbulent flame results. These experimentally determined resolution and noise correction techniques are combined to give measurements of the mean thermal dissipation that are essentially fully resolved and noise-free. The prospects of using spectral results from high-resolution 1-D Rayleigh imaging measurements to design filtering schemes for Raman-based measurements of mixture fraction dissipation are also discussed.
Direct numerical simulation of a three-dimensional spatially developing turbulent slot-burner Bunsen flame has been performed with a new reduced methane-air mechanism. The mechanism, derived from sequential application of directed relation graph theory, sensitivity analysis and computational singular perturbation over the GRI-1.2 detailed mechanism is non-stiff and tailored to the lean conditions of the DNS. The simulation is performed for three flow through times, long enough to achieve statistical stationarity. The turbulence parameters have been chosen such that the combustion occurs in the thin reaction zones regime of premixed combustion. The data is analyzed to study possible influences of turbulence on the structure of the preheat and reaction zones. The results show that the mean thickness of the turbulent flame, based on progress variable gradient, is greater than the corresponding laminar flame. The effects of flow straining and flame front curvature on the mean flame thickness are quantified through conditional means of the thickness and by examining the balance equation for the evolution of the flame thickness. Finally, conditional mean reaction rate of key species compared to the laminar reaction rate profiles show that there is no significant perturbation of the heat release layer.
Oxygen/carbon dioxide recycle coal combustion is actively being investigated because of its potential to facilitate CO2 sequestration and to achieve emission reductions. In the work reported here, the effect of enhanced oxygen levels and CO2 bath gas is independently analyzed for their influence on single-particle pulverized coal ignition of a U.S. eastern bituminous coal. The experiments show that the presence of CO2 and a lower O2 concentration increase the ignition delay time but have no measurable effect on the time required to complete volatile combustion, once initiated. For the ignition process observed in the experiments, the CO 2 results are explained by its higher molar specific heat and the O2 results are explained by the effect of O2 concentration on the local mixture reactivity. Particle ignition and devolatilization properties in a mixture of 30% O2 in CO2 are very similar to those in air.
A 70-MA, 7-MV, ∼100-ns driver for a Z-pinch Inertial Fusion Energy (Z-IFE) power plant has been proposed. In this summary we address the transition region between the 70 Linear Transformer Driver (LTD) modules and the center Recyclable Transmission Line (RTL) load section, which convolves from the coaxial vacuum Magnetically Insulated Transmission Lines (MITL) to a parallel tri-plate and then a bi-plate disk feed. An inductive annular chamber terminates one side of the tri-plate in a manner that preserves vacuum and electrical circuit integrity without significant energy losses. The simplicity is offset by the disadvantage of the chamber size, which is proportional to the driver impedance and decreases with the addition of more parallel modules. Inductive isolation chamber sizes are estimated in this paper, based on an optimized LTD equivalent circuit simulation source driving a matched load using transmission line models. We consider the trade-offs between acceptable energy loss and the size of the inductive isolation chamber; accepting a 6% energy loss would only require a 60-nH chamber.
We report what is believed to be the first application of coherent anti-Stokes Raman scattering (CARS) to full-scale fire testing. A CARS instrument has been constructed at the newly commissioned FLAME (Fire Laboratory for Accreditation of Models and Experiments) facility at Sandia, where the CARS system has been used for thermometry in 2-m-diameter, turbulent methanol pool fires. Fielding of CARS in such a large-scale facility presents several challenges, including long-distance propagation of laser beams, shielding of optics from intense heat, the impact of beam steering and fiber-optic coupling of the CARS signal to remotely located detection equipment. The details of a CARS instrument that meets these challenges are presented, along with the construction of the unique new FLAME facility itself, which has been designed to accommodate optical and laser-based diagnostics to full-scale fire experimentation. The performance of the CARS instrument is investigated in a premixed methane-air flat flame to estimate the precision in single-shot CARS temperatures. Single-shot CARS spectra and best-fit temperatures from a methanol pool fire are presented, and an estimate of the pdf of the temperature fluctuations from the pool-fire environment is obtained.
This paper examined the high frequency time harmonic localization of modal fields in two dimensional cavities along unstable periodic orbits. The elliptic formalism, combined with the random phase approach, allowed the treatment of both convex and concave boundary geometries.
It is shown that for any material or structural model expressible as a Masing model, there exists a unique parallel-series (displacement-based) Iwan system that characterizes that model as a function of displacement history. This poses advantages both in terms of more convenient force evaluation in arbitrary deformation histories as well as in terms of model inversion. Characterization as an Iwan system is demonstrated through the inversion of the Ramberg-Osgood model, a force(stress)-based material model that is not explicitly invertible. An implication of the inversion process is that direct, rigorous comparisons of different Masing models, regardless of the ability to invert their constitutive relationship, can be achieved through the comparison of their associated Iwan distribution densities.