We present fabrication and characterization of a membrane based on carbon nanotubes (CNTs) and parylene. Carbon nanotubes have shown orders of magnitude enhancement in gas and water permeability compared to estimates generated by conventional theories [1, 2]. Large area membranes that exhibit flux enhancement characteristics of carbon nanotubes may provide an economical solution to a variety of technologies including water desalination [3] and gas sequestration [4]. We report a novel method of making carbon nanotube-based, robust membranes with large areas. A vertically aligned dense carbon nanotube array is infiltrated with parylene. Parylene polymer creates a pinhole free transparent film by exhibiting high surface conformity and excellent crevice penetration. Using this moisture-, chemical- and solvent-resistant polymer creates carbon nanotube membranes that promise to exhibit high stability and biocompatibility. CNT membranes are formed by releasing a free-standing film that consists of parylene-infiltrated CNTs, followed by CNT uncapping on both sides of the composite material. Thus fabricated membranes show flexibility and ductility due to the parylene matrix material, as well as high permeability attributed to embedded carbon nanotubes. These membranes have a potential for applications that may require high flux, flexibility and durability.

Increasing evidence suggests that a combination of host genetics and the composition of the gut microbiota are important for development of Crohn's disease (CD). Our aim was to study identical twins with CD to determine microbial factors independently of host genetics. Fecal samples were studied from 10 monozygotic twin pairs with CD (discordant n=6, concordant n=4) and 8 healthy twin pairs. DNA was extracted, 16S rRNA genes were PCR amplified and T-RFLP fingerprints generated using general bacterial and Bacteroides group specific primers. The microbial communities were also profiled based on their % G+C contents. Bacteroides 16S rRNA genes were cloned and sequenced from a subset of the samples. The bacterial diversity in each sample and similarity indices between samples were estimated based on the T-RFLP data using a combination of statistical approaches. Healthy individuals had a significantly higher bacterial diversity compared to individuals with CD. The fecal microbial communities were more similar between healthy twins than between twins with CD, especially when these were discordant for the disease. The microbial community profiles of individuals with ileal CD were significantly different from healthy individuals and those with colonic CD. Also, CD individuals had a lower relative abundance of B. uniformis and …

The Hanford K Basin Closure Project involves the retrieval, transfer and processing of radioactive contaminated slurries containing partially corroded spent nuclear fuel from the K Basin spent fuel pools. The spent fuel is primarily metallic fuel from the operation of the Hanford reactors. The Sludge Treatment Project is being designed to treat and package this material in preparation for ultimate disposal. The processing of the contaminated slurries includes further corrosion of the remaining uncorroded uranium metal in a large heated vessel to form a more stable metal oxide for packaging and storage.

We study the photo-induced insulator-metal transition in VO2, correlating threshold and dynamic evolution with excitation wavelength. In high-quality single crystal samples, we find that switching can only be induced with photon energies above the 670-meV gap. This contrasts with the case of polycrystalline films, where formation of the metallic state can also be triggered with photon energies as low as 180 meV, well below the bandgap. Perfection of this process may be conducive to novel schemes for optical switches, limiters and detectors, operating at room temperature in the mid-IR.

Lattice mismatch strains are widely known to controlnanoscale pattern formation in heteroepitaxy, but such effects have notbeen exploited in colloidal nanocrystal growth. We demonstrate acolloidal route to synthesizing CdS-Ag2S nanorod superlattices throughpartial cation exchange. Strain induces the spontaneous formation ofperiodic structures. Ab initio calculations of the interfacial energy andmodeling of strain energies show that these forces drive theself-organization. The nanorod superlattices exhibit high stabilityagainst ripening and phase mixing. These materials are tunablenear-infrared emitters with potential applications as nanometer-scaleoptoelectronic devices.

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This letter describes how to perform model-independent searches for new pair-produced color octet particles that each subsequently decay into two jets plus missing energy at the Tevatron. Current searches are not sensitive to all regions of parameter space because they employ CMSSM-motivated cuts. Optimizing the H{sub T} and E{sub T} cuts expands the sensitivity of searches for all kinematically allowed decays.

Crevice corrosion may be limited by the capacity of the external cathodic region to support anodic dissolution currents within the crevice. The analysis here focuses on behavior of metal surfaces covered by a thin ({approx}microns) layer of the electrolyte film including particulates. The particulates can affect the cathode current capacity (I{sub total}) by increasing the solution resistance (''volume effect'') and by decreasing the electrode area (''surface effect''). In addition, there can be particulate effects on oxygen reduction kinetics and oxygen transport. This work simulates and characterizes the effect of a uniform particulate monolayer on the cathode current capacity for steady state conditions in the presence of a thin electrolyte film. Particulate configurations with varying particle size, shape, arrangement, volume fraction, and electrode area coverage were numerically modeled as a function of the properties of the system. It is observed that the effects of particles can be fully accounted for in terms of two corrections: the volume blockage effect on the electrolyte resistivity can be correlated using Bruggeman's equation, and the electrode coverage effect can be modeled in terms of a simple area correction to the kinetics expression. For the range of parameters analyzed, applying these two correction factors, cathodes covered …

This report summarizes work to develop a novel distributed fiber-optic micro-sensor that is capable of detecting common fossil fuel gases in harsh environments. During the 32-month research and development (R&D) program, GE Global Research successfully synthesized sensing materials using two techniques: sol-gel based fiber surface coating and magnetron sputtering based fiber micro-sensor integration. Palladium nanocrystalline embedded silica matrix material (nc-Pd/Silica), nanocrystalline palladium oxides (nc-PdO{sub x}) and palladium alloy (nc-PdAuN{sub 1}), and nanocrystalline tungsten (nc-WO{sub x}) sensing materials were identified to have high sensitivity and selectivity to hydrogen; while the palladium doped and un-doped nanocrystalline tin oxide (nc-PdSnO{sub 2} and nc-SnO{sub 2}) materials were verified to have high sensitivity and selectivity to carbon monoxide. The fiber micro-sensor comprises an apodized long-period grating in a single-mode fiber, and the fiber grating cladding surface was functionalized by above sensing materials with a typical thickness ranging from a few tens of nanometers to a few hundred nanometers. GE found that the morphologies of such sensing nanomaterials are either nanoparticle film or nanoporous film with a typical size distribution from 5-10 nanometers. nc-PdO{sub x} and alloy sensing materials were found to be highly sensitive to hydrogen gas within the temperature range from ambient to 150 …

The present program is centered on the experimental study of shock-induced interfacial fluid instabilities. Both 2-D (near-sinusoids) and 3-D (spheres) initial conditions are studied in a large, vertical square shock tube facility. The evolution of the interface shape, its distortion, the modal growth rates and the mixing of the fluids at the interface are all objectives of the investigation. In parallel to the experiments, calculations are performed using the Raptor code, on platforms made available by LLNL. These flows are of great relevance to both ICF and stockpile stewardship. The involvement of four graduate students is in line with the national laboratories' interest in the education of scientists and engineers in disciplines and technologies consistent with the labs' missions and activities.

The 1607-F1 Sanitary Sewer System (124-F-1), consisted of a septic tank, drain field, and associated pipelines that received sanitary waste water from the 1701-F Gatehouse, 1709-F Fire Station, and the 1720-F Administrative Office via the 100-F-26:8 pipelines. The septic tank required remedial action based on confirmatory sampling. In accordance with this evaluation, the verification sampling results support a reclassification of this site to Interim Closed Out. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

The Pyramid Lake Paiute Tribe is a federally recognized Tribe residing on the Pyramid Lake Reservation in western Nevada. The funding for this project was used to identify blind geothermal systems disconnected from geothermal sacred sites and develop a Tribal energy corporation for evaluating potential economic development for profit.

The 100-F-26:8 waste site consisted of the underground pipelines that conveyed sanitary waste water from the 1701-F Gatehouse, 1709-F Fire Station, and the 1720-F Administrative Office to the 1607-F1 septic tank. The site has been remediated and presently exists as an open excavation. In accordance with this evaluation, the verification sampling results support a reclassification of this site to Interim Closed Out. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

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The purpose of this study was to examine the hypothesis that clastic dikes could form a preferential flow path through the vadose zone to the water table at the Hanford Site. Clastic dikes are subvertical structures that form within sedimentary sequences after deposition, and cut across the original sedimentary layers. They are common throughout the Hanford Site, often occurring in organized polygonal networks. In the initial phase of the project, we analyzed the large-scale geometry of the clastic dikes and developed an algorithm for simulating their spatial distribution. This result will be useful in providing maps of the potential distribution of clastic dikes in areas where they are not exposed at the surface (e.g., where covered by windblown sand or by construction of facilities like tank farms at the surface). In addition to the study of the large scale distribution of the dikes, a major focus of the project was on field, laboratory, and modeling studies of the hydrogeologic al properties of the clastic dikes and the effect that they have on transport of water through the vadose zone. These studies were performed at two field locations at the Hanford Site. We performed an extensive series of field and laboratory …

This is a collaborative LDRD Exploratory Research project involving four directorates--Energy & Environment, Engineering, NAI and Computation. The project seeks to answer the following critical questions regarding atmospheric releases--''How much material was released? When? Where? and What are the potential consequences?'' Inaccurate estimation of the source term can lead to gross errors, time delays during a crisis, and even fatalities. We are developing a capability that seamlessly integrates observational data streams with predictive models in order to provide the best possible estimates of unknown source term parameters, as well as optimal and timely situation analyses consistent with both models and data. Our approach utilizes Bayesian inference and stochastic sampling methods (Markov Chain and Sequential Monte Carlo) to reformulate the inverse problem into a solution based on efficient sampling of an ensemble of predictive simulations, guided by statistical comparisons with data. We are developing a flexible and adaptable data-driven event-reconstruction capability for atmospheric releases that provides (1) quantitative probabilistic estimates of the principal source-term parameters (e.g., the time-varying release rate and location); (2) predictions of increasing fidelity as an event progresses and additional data become available; and (3) analysis tools for sensor network design and uncertainty studies. Our computational framework incorporates …

Sludge has accumulated in the K East (KE) and K West (KW) Basins at the Hanford Site. This sludge contains metallic uranium and uranium oxides that will corrode, hydrate, and generate and consume gases during containerized storage. From these corrosion reactions, two sludge expansion mechanisms can be expected: 1) expansion of the volume of the sludge solids from the generation of corrosion oxidation products that occupy more space than the starting-state sludge; and 2) expansion of the bulk sludge volume from the retention of hydrogen gas bubbles. This report provides a review and updated projections of the volumetric expansion occurring due to corrosion and gas retention during the containerized storage of K Basin sludge. New design and safety basis volume expansion values are provided for the following sludge streams: KW Floor, KW North Loadout Pit, KW canister, and fuel piece sludge.

To investigate and verify the formation of <111>-type 4-arm multi-junction by the dislocation reaction of 1/2[111] [b1] + 1/2[{bar 1}1{bar 1}] [b2] + 1/2[{bar 1}{bar 1}1] [b3] = 1/2[{bar 1}11] [b4], which has recently been discovered through computer simulations conducted by Vasily Bulatov and his colleagues.

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Lignocellulosic accounts for a large percentage of material that can be utilized for biofuels. The most costly part of lignocellulosic material processing is the initial hydrolysis of the wood which is needed to circumvent the lignin barrier and the crystallinity of cellulose. Enzymes will play an increased role in this conversion in that they potentially provide an alternative to costly and caustic high temperature and acid treatment. The increasing use of enzymes in biotechnology is facilitated by both continued improvements in enzyme technology but also in the discovery of new and novel enzymes. The present proposal is aimed at identifying the enzymes which are known to depolymerize woody biomass. Fundamental understanding of how nature gains access to cellulose and hemicellulose will impact all applications. Because fungi are the only known microbes capable of circumventing the lignin barrier, knowledge of the enzyme they use is of great potential for biofuel processing. Nature has evolved different fungal mechanisms for enzymatic hydrolysis of wood. Most notable are the white-rot fungi (wrf) and the brown-rot fungi (brf). This proposed research aims at determining the complete transcriptome of three wrf and two brf to determine the enzymes involved in lignocellulose degradation. The transcriptome work will …

Welcome to the annual 2007 Environmental Remediation Sciences Program (ERSP) Principal Investigators (PIs) meeting. The purpose of this meeting is to bring together all of the lead PIs and key Co-PIs in the program to share and review the results of funded research from the past year. This meeting allows program managers from the Environmental Remediation Sciences Division (ERSD) within the Office of Biological and Environmental Research (OBER) to gauge the progress and significance of the funded research, and it is also an important venue to showcase ERSP research to interested parties within DOE and other invited federal agency representatives. Additionally, these meetings should serve as an opportunity for funded PIs to view their research in the context of the entire ERSP portfolio. Past ERSP meetings have been very important venues for detailed discussion of research results among PIs, development of new research ideas, fostering new collaborations and discussion with ERSD program managers on future research efforts and/or initiatives within the program. In short, these meetings are an important resource for both program managers and PIs. There will be only one ERSP PI meeting for 2007. In years past, ERSD has sponsored two PI meetings, one in the spring and …

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Cloud optical depths have been measured using multifilter rotating shadowband radiometers (MFRSRs) at Barrow and Atqasuk, and liquid water paths have been measured at Barrow using a microwave radiometer (MWR) during the warm season (June-September) in 1999. Comparisons have been made between these quantities and the corresponding ones determined from the ECMWF GCM. Hour-by-hour comparisons of cloud optical depths show considerable scatter. The scatter is reduced, but is still substantial, when the averaging period is increased to ''daily'' averages, i.e., the time period each day over which the MFRSR can make measurements. This period varied between 18 hours in June and 6 hours in September. Preliminary results indicate that, for measured cloud optical depths less than approximately 25, the ECMWF has a low bias in its predictions, consistent with a low bias in predicted liquid water path. Based on a more limited set of data, the optical depths at Atqasuk were found to be generally lower than those at Barrow, a trend at least qualitatively captured by the ECMWF model. Analyses to identify the cause of the biases and the considerable scatter in the predictions are continuing.