Determination of the strains in a polycrystalline materialusing 4-D XRD reveals sub-grain and grain-to-grain behavior as a functionof stress. Here 4-D XRD involves an experimental procedure usingpolychromatic micro-beam X-radiation (micro-Laue) to characterizepolycrystalline materials in spatial location as well as with increasingstress. The in-situ tensile loading experiment measured strain in a modelaluminum-sapphire metal matrix composite using the Advanced Light Source,Beam-line 7.3.3. Micro-Laue resolves individual grains in thepolycrystalline matrix. Results obtained from a list of grains sorted bycrystallographic orientation depict the strain states within and amongindividual grains. Locating the grain positions in the planeperpendicular to the incident beam is trivial. However, determining theexact location of grains within a 3-D space is challenging. Determiningthe depth of the grains within the matrix (along the beam direction)involved a triangulation method tracing individual rays that producespots on the CCD back to the point of origin. Triangulation wasexperimentally implemented by simulating a 3-D detector capturingmultiple diffraction images while increasing the camera to sampledistance. Hence by observing the intersection of rays from multiple spotsbelonging to the corresponding grain, depth is calculated. Depthresolution is a function of the number of images collected, grain to beamsize ratio, and the pixel resolution of the CCD. The 4DXRD methodprovides grain morphologies, strain …

A 2-stage detector was designed to find rho-independent transcription terminators in the Escherichia coli genome. The detector includes a Stochastic Context Free Grammar (SCFG) component and a Support Vector Machine (SVM) component. To find terminators, the SCFG searches the intergenic regions of nucleotide sequence for local matches to a terminator grammar that was designed and trained utilizing examples of known terminators. The grammar selects sequences that are the best candidates for terminators and assigns them a prefix, stem-loop, suffix structure using the Cocke-Younger-Kasaami (CYK) algorithm, modified to incorporate energy affects of base pairing. The parameters from this inferred structure are passed to the SVM classifier, which distinguishes terminators from non-terminators that score high according to the terminator grammar. The SVM was trained with negative examples drawn from intergenic sequences that include both featureless and RNA gene regions (which were assigned prefix, stem-loop, suffix structure by the SCFG), so that it successfully distinguishes terminators from either of these. The classifier was found to be 96.4% successful during testing.

This report describes a robust and generalized method for the clustering of various human breast cell lines in 3D and describes the preparation of cellular extracts from these cultures for molecular analysis.

Article about various events that took place in Austin, Texas throughout 2006.

The effect of enhanced crater formation has been demonstrated experimentally when multiple and delayed shaped charge jets impact and penetrate concrete. The concept for enhancement utilizes a single follow-on jet at the centerline of holes produced by multiple precursor jets penetrating the surrounding the region. Calculations of the 3D crater enhancement phenomena have been conducted with multiple rods to simulate the steady state portion of the multiple jet penetration process. It is expected that this analysis methodology will be beneficial for optimization of the multiple jet crater enhancement application. We present calculated results using ALE3D where the model uses the standard Gruneisen equation of state combined with a rate dependent strength model including material damage parameters. This study focuses on the concrete material damage model as a representation of the portion of the target that would eventually be ejected creating a large bore-hole. The calculations are compared with the experimental evidence and limitations of the modeling approach are discussed.

As scientific codes become more complex and involve larger numbers of developers and algorithms, chances for algorithmic implementation mistakes increase. In this environment, code verification becomes essential to building confidence in the code implementation. This paper will present first results of a new code verification effort within LLNL's B Division. In particular, we will show results of code verification of the LLNL ASC ARES code on the test problems: Su Olson non-equilibrium radiation diffusion, Sod shock tube, Sedov point blast modeled with shock hydrodynamics, and Noh implosion.

M-ary pulse position modulation (M-ary PPM) is an alternative to on-off-keying (OOK) that transmits multiple bits as a single symbol occupying a frame of M slots. PPM does not require thresholding as in OOK signaling, instead performing a comparison test among all slots in a frame to make the slot decision. Combining PPM with optical code division multiple access (PPM/O-CDMA) adds the benefit of supporting multiple concurrent, asynchronous bursty PPM users. While the advantages of PPM/O-CDMA are well known, implementing a receiver that performs comparison test can be difficult. This paper describes the design of a novel array receiver for M-ary PPM/O-CDMA (M = 4) where the received signal is mapped onto an xy-plane whose quadrants define the PPM slot decision by means of an associated control law. The receiver does not require buffering or nonlinear operations. In this paper we describe a planar lightwave circuit (PLCs) implementation of the receiver. We give detailed numerical simulations that test the concept and investigate the effects of multi-access interference (MAI) and optical beat interference (OBI) on the slot decisions. These simulations provide guidelines for subsequent experimental measurements that will be described.

We report a passively mode-locked fiber-based oscillator that has no internal dispersion-compensating gratings. This design, the first of its kind, produces 25 nJ pulses at 80 MHz with the pulses compressible to 150 fs. The pulses appear to be self-similar and initial data imply that their energy is further scalable.

The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, sulfate). The pretreatment process acidifies the sludge with nitric and formic acids, adds the glass formers as glass frit, then concentrates the resulting slurry to approximately 50 weight percent (wt%) total solids. This slurry is fed to the joule-heated melter where the remaining water is evaporated followed by calcination of the solids and conversion to glass. The Savannah River National Laboratory (SRNL) is currently assisting DWPF efforts to increase throughput of the melter. As part of this effort, SRNL has investigated methods to increase the solids content of the melter feed to reduce the heat load required to complete the evaporation of water and allow more of the energy available to calcine and vitrify the waste. The process equipment in the facility is fixed and cannot process materials with high yield stresses, therefore increasing the solids content will require that the yield stress of the melter feed …

A gamma-ray survey and analysis of sixteen riverbed samples from the Reedy River watershed near Simpsonville, SC were conducted and compared with national and international studies of primordial radionuclides. The study reported here follows on a recent discovery of anomalously high uranium concentrations in several private well waters in the area near Simpsonville, SC. A HPGe spectrometer was used for quantification of gamma emitting radionuclides in the sediments. All sediments contained radionuclides from the uranium and thorium series as well as {sup 40}K. Uranium-238 concentrations in sediment samples ranged from 11.1 to 74.2 Bq kg{sup -1}. The measured radionuclide concentrations were compared with data from UNSCEAR and NURE reports. The river and stream sediment data were augmented by in situ NaI(Tl) gamma-ray spectrometer measurements. Comparisons between the ex-situ and in-situ measurements indicate equivalently distributed uranium in the surface soils and stream sediments, the source of which is likely attributed to the monazite belts that are known to exist in the area.

A search for nuclear resonance fluorescence excitations in {sup 235}U and {sup 239}Pu within the energy range of 1.0- to 2.5-MeV was performed using a 4-MeV continuous bremsstrahlung source at the High Voltage Research Laboratory at the Massachusetts Institute of Technology. Measurements utilizing high purity Ge detectors at backward angles identified 9 photopeaks in {sup 235}U and 12 photopeaks in {sup 239}Pu in this energy range. These resonances provide unique signatures that allow the materials to be non-intrusively detected in a variety of environments including fuel cells, waste drums, vehicles and containers. The presence and properties of these states may prove useful in understanding the mechanisms for mixing low-lying collective dipole excitations with other states at low excitations in heavy nuclei.

Transuranic solid waste that has been generated as a result of the production of nuclear material for the United States defense program at the Savannah River Site (SRS) has been stored in more than 30,000 55-gallon drums and various size carbon steel boxes since 1953. Nearly two thirds of those containers have been processed and shipped to the Waste Isolation Pilot Plant. Among the containers assayed so far, the results indicate several drums with fissile inventories significantly higher (600-1000 grams {sup 239}Pu) than their original assigned values. While part of this discrepancy can be attributed to the past limited assay capabilities, human errors are believed to be the primary contributor. This paper summarizes an assessment of the probability of occurrence of a criticality accident during handling of the remaining transuranic waste containers at SRS.

Several countries are considering geological repositories for the storage of nuclear waste. Most of the environments for these repositories will be reducing in nature, except for the repository in the US, which is going to be oxidizing. For the reducing repositories, alloys such as carbon steel, copper, stainless steels and titanium are being evaluated. For the repository in the US, some of the most corrosion resistant commercially available alloys are being investigated. This paper presents a summary of the behavior of the different materials under consideration for the repositories and the current understanding of the degradation modes of the proposed alloys in ground water environments from the point of view of general corrosion, localized corrosion and environmentally assisted cracking.

Absolute line emission cross sections are presented for 1 keV/amu charge exchange collisions of multiply charged solar wind ions with H{sub 2}O, H, O, CO{sub 2}, and CO cometary targets. The present calculations are contrasted with available laboratory data. A parameter-free model is used to successfully predict the recently observed x-ray spectra of comet C/LINEAR 1999 S4. We show that the resulting spectrum is extremely sensitive to the time variations of the solar wind composition. Our results suggest that orbiting x-ray satellites may be a viable way to predict the solar wind intensities and composition on the Earth many hours before the ions reach the earth.

We report on recent developments with the Purgatorio code, a new implementation of Liberman's Inferno model. This fully relativistic average atom code uses phase shift tracking and an efficient refinement scheme to provide an accurate description of continuum states. The resulting equations of state accurately represent the atomic shell-related features which are absent in Thomas-Fermi-based approaches. We discuss various representations of the exchange potential and some of the ambiguities in the choice of the effective charge Z* in average atom models, both of which affect predictions of electrical conductivities and radiative properties.

Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or ''mineralized'' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydroceramics. All but one of the nine monoliths tested met the <2g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; …

The non-equilibrium dynamics of mixing, oscillations and equilibration is studied in a field theory of flavored neutral mesons that effectively models two flavors of mixed neutrinos, in interaction with other mesons that represent a thermal bath of hadrons or quarks and charged leptons. This model describes the general features of neutrino mixing and relaxation via charged currents in a medium. The reduced density matrix and the non-equilibrium effective action that describes the propagation of neutrinos is obtained by integrating out the bath degrees of freedom. We obtain the dispersion relations, mixing angles and relaxation rates of ``neutrino'' quasiparticles. The dispersion relations and mixing angles are of the same form as those of neutrinos in the medium, and the relaxation rates are given by $\Gamma_1(k) = \Gamma_{ee}(k) \cos^2\theta_m(k)+\Gamma_{\mu\mu}(k)\sin^2\theta_m(k); \Gamma_2(k)= \Gamma_{\mu\mu}(k) \cos^2\theta_m(k)+\Gamma_{ee}(k)\sin^2\theta_m(k) $ where $\Gamma_{\alpha\alpha}(k)$ are the relaxation rates of the flavor fields in \emph{absence} of mixing, and $\theta_m(k)$ is the mixing angle in the medium. A Weisskopf-Wigner approximation that describes the asymptotic time evolution in terms of a non-hermitian Hamiltonian is derived. At long time $>>\Gamma^{-1}_{1,2}$ ``neutrinos'' equilibrate with the bath. The equilibrium density matrix is nearly diagonal in the basis of eigenstates of an \emph{effective Hamiltonian that includes self-energy corrections …

Article on phenylpropanoid glycosyltransferases from osage orange (Maclura pomifera) fruit.

Ablative targets for the National Ignition Campaign (NIC) have been fabricated by sputter coating spherical mandrels made of glow discharge polymer (GDP) with graded copper doped beryllium (Be) layers. The inner mandrel must be completely removed to meet specific ignition design requirements. The process of removing the mandrel requires elevated temperature in the presence of oxygen. However, elevating the temperature in air also oxidizes the Be and can cause blistering on the inner surface of the Be shell. This paper will discuss a refined technique, which removes the GDP mandrel without compromising the integrity of the inner Be surface. The oxygen gradient that develops during the mandrel removal and the impact of its presence will also be discussed.

Uranium-lead ratios (commonly represented as {sup 238}U/{sup 204}Pb = {mu}) calculated for the sources of martian basalts preserve a record of petrogenetic processes that operated during early planetary differentiation and formation of martian geochemical reservoirs. To better define the range of {mu} values represented by the source regions of martian basalts, we completed U-Pb elemental and isotopic analyses on whole rock, mineral and leachate fractions from the martian meteorite Queen Alexandra Range 94201 (QUE 94201). The whole rock and silicate mineral fractions have unradiogenic Pb isotopic compositions that define a narrow range ({sup 206}Pb/{sup 204}Pb = 11.16-11.61). In contrast, the Pb isotopic compositions of weak HCl leachates are more variable and radiogenic. The intersection of the QUE 94201 data array with terrestrial Pb in {sup 206}Pb/{sup 204}Pb-{sup 207}Pb/{sup 204}Pb-{sup 208}Pb/{sup 204}Pb compositional space is consistent with varying amounts of terrestrial contamination in these fractions. We calculate that only 1-7% contamination is present in the purified silicate mineral and whole rock fractions, whereas the HCl leachates contain up to 86% terrestrial contamination. Despite the contamination, we are able to use the U-Pb data to determine the initial {sup 206}Pb/{sup 204}Pb of QUE 94201 (11.086 {+-} 0.008) and calculate the {mu} value …

We calculate X-ray line polarization degrees for cases with axial symmetry using a collisional-radiative magnetic-sublevel atomic kinetics model and the properties of multipole radiation fields. This approach is well-suited for problems where the alignment is determined by the competition between many atomic processes. We benchmark this method against polarization measurements performed at the Livermore electron beam ion trap, and we study the 3-to-2 cascade effects on the polarization of 2-to-1 lines in He-like Fe.

We report the results of a first-principles study of dissociative electron attachment (DEA) to H{sub 2}O. The cross sections were obtained from nuclear dynamics calculations carried out in full dimensionality within the local complex potential model by using the multi-configuration time-dependent Hartree method. The calculations employ our previously obtained global, complex-valued, potential energy surfaces for the three ({sup 2}B{sub 1}, {sup 2}A{sub 1}, and {sup 2}B{sub 2}) electronic Feshbach resonances involved in this process. These three metastable states of H{sub 2}O{sup -} undergo several degeneracies, and we incorporate both the Renner-Teller coupling between the {sup 2}B{sub 1} and {sup 2}A{sub 1} states, as well as the conical intersection between the {sup 2}A{sub 1} and {sup 2}B{sub 2} states, into our treatment. The nuclear dynamics are inherently multi-dimensional and involve branching between different final product arrangements as well as extensive excitation of the diatomic fragment. Our results successfully mirror the qualitative features of the major fragment channels observed, but are less successful in reproducing the available results for some of the minor channels. We comment on the applicability of the local complex potential model to such a complicated resonant system.

Article exploring the reasons why near-death experiences may not occur during induced cardiac arrest.

Article describes the Cherokee Nation's striving to preserve several important elements of their political culture when facing the allotment of their tribal land in severalty. Their proposals for land ownership, judicial administration, and representation in the United States Congress were summarily rejected by the members of the Dawes Commission during the 1898-1899 talks.