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Sample records for gas single shell

  1. FLAMMABLE GAS DIFFUSION THROUGH SINGLE SHELL TANK (SST) DOMES

    SciTech Connect

    MEACHAM, J.E.

    2003-11-10

    This report quantified potential hydrogen diffusion through Hanford Site Single-Shell tank (SST) domes if the SSTs were hypothetically sealed airtight. Results showed that diffusion would keep headspace flammable gas concentrations below the lower flammability limit in the 241-AX and 241-SX SST. The purpose of this document is to quantify the amount of hydrogen that could diffuse through the domes of the SSTs if they were hypothetically sealed airtight. Diffusion is assumed to be the only mechanism available to reduce flammable gas concentrations. The scope of this report is limited to the 149 SSTs.

  2. Gas retention and release behavior in Hanford single-shell waste tanks

    SciTech Connect

    Stewart, C.W.; Brewster, M.E.; Gauglitz, P.A.; Mahoney, L.A.; Meyer, P.A.; Recknagle, K.P.; Reid, H.C.

    1996-12-01

    This report describes the current understanding of flammable gas retention and release in Hanford single-shell waste tanks based on theory, experimental results, and observations of tank behavior. The single-shell tanks likely to pose a flammable gas hazard are listed and described, and photographs of core extrusions and the waste surface are included. The credible mechanisms for significant flammable gas releases are described, and release volumes and rates are quantified as much as possible. The only mechanism demonstrably capable of producing large ({approximately}100 m{sup 3}) spontaneous gas releases is the buoyant displacement, which occurs only in tanks with a relatively deep layer of supernatant liquid. Only the double-shell tanks currently satisfy this condition. All release mechanisms believed plausible in single-shell tanks have been investigated, and none have the potential for large spontaneous gas releases. Only small spontaneous gas releases of several cubic meters are likely by these mechanisms. The reasons several other postulated gas release mechanisms are implausible or incredible are also given.

  3. Data and Observations of Single Shell Flammable Gas Watch List Tank Behavior

    SciTech Connect

    HEDENGREN, D.C.

    2001-02-14

    This report summarizes the available data, observations, and analyses performed relating to flammable gas generation, retention, and release in the nineteen single-shell nuclear waste storage tanks at the Hanford Site that are on the Flammable Gas Watch List (Public Law 101-510 1990). The tanks and the waste they contain are described in terms of their fill history, chemistry, and waste physical properties and configuration. In-situ measurement and monitoring systems are described and their data are summarized. The gas generation rates, retained gas volumes, and the spontaneous and induced gas release history of each tank are discussed. Saltwell pumping activities are also summarized, and the effects of pumping on gas generation, retention, and release are described.

  4. Gas Releases During Saltcake Dissolution for Retrieval of Single-Shell Tank Waste

    SciTech Connect

    Stewart, Charles W.

    2001-07-31

    It is possible to retrieve a large fraction of soluble waste from the Hanford single-shell waste tanks (SST) by dissolving it with water. This retrieval method will be demonstrated in U-107 and S-112 in the next few years. If saltcake dissolution proves practical and effective, many of the saltcake SSTs may be retrieved by this method. Many of the SSTs retain a large volume of flammable gas that will be released into the tank headspace as the waste dissolves. This report describes the physical processes that control dissolution and gas release. Calculation results are shown describing the headspace hydrogen concentration transient during dissolution. The observed spontaneous and induced gas releases from SSTs is summarized and the dissolution of the crust layer in SY-101 is discussed as a recent example of full-scale dissolution of saltcake containing a very large volume of retained gas. The report concludes that the dissolution rate is self limiting and gas release rates are relatively low.

  5. Gas Releases During Saltcake Dissolution for Retrieval of Single-Shell Tank Waste, Rev. 1

    SciTech Connect

    Stewart, Charles W.

    2001-12-28

    It is possible to retrieve a large fraction of soluble waste from the Hanford single-shell waste tanks (SSTs) by dissolving it with water. This retrieval method will be demonstrated in Tanks U-107 and S-112 in the next few years. If saltcake dissolution proves practical and effective, many of the saltcake SSTs may be retrieved by this method. Many of the SSTs retain flammable gas that will be released into the tank headspace as the waste dissolves. This report describes the physical processes that control dissolution and gas release. Calculation results are shown and describe how the headspace hydrogen concentration evolves during dissolution. The observed spontaneous and induced gas releases from SSTs are summarized, and the dissolution of the crust layer in SY-101 is discussed as a recent example of full-scale dissolution of saltcake containing a large volume of retained gas. The report concludes that the dissolution rate is self-limiting and that gas release rates are relatively low.

  6. A safety assessment of rotary mode core sampling in flammable gas single shell tanks: Hanford Site, Richland, Washington

    SciTech Connect

    Raymond, R.E.

    1996-04-15

    This safety assessment (SA) addresses each of the required elements associated with the installation, operation, and removal of a rotary-mode core sampling (RMCS) device in flammable-gas single-shell tanks (SSTs). The RMCS operations are needed in order to retrieve waste samples from SSTs with hard layers of waste for which push-mode sampling is not adequate for sampling. In this SA, potential hazards associated with the proposed action were identified and evaluated systematically. Several potential accident cases that could result in radiological or toxicological gas releases were identified and analyzed and their consequences assessed. Administrative controls, procedures and design changes required to eliminate or reduce the potential of hazards were identified. The accidents were analyzed under nine categories, four of which were burn scenarios. In SSTS, burn accidents result in unacceptable consequences because of a potential dome collapse. The accidents in which an aboveground burn propagates into the dome space were shown to be in the ``beyond extremely unlikely`` frequency category. Given the unknown nature of the gas-release behavior in the SSTS, a number of design changes and administrative controls were implemented to achieve these low frequencies. Likewise, drill string fires and dome space fires were shown to be very low frequency accidents by taking credit for the design changes, controls, and available experimental and analytical data. However, a number of Bureau of Mines (BOM) tests must be completed before some of the burn accidents can be dismissed with high confidence. Under the category of waste fires, the possibility of igniting the entrapped gases and the waste itself were analyzed. Experiments are being conducted at the BOM to demonstrate that the drill bit is not capable of igniting the trapped gas in the waste. Laboratory testing and thermal analysis demonstrated that, under normal operating conditions, the drill bit will not create high

  7. Vapor and gas sampling of single-shell tank 241-BX-103 using the in situ vapor sampling system

    SciTech Connect

    Lockrem, L.L.

    1997-08-05

    The Vapor Issue Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-BX-103. This document presents In Situ Vapor Sampling System (ISVS) data resulting from the August 1, 1996 sampling of SST 241-BX-103. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which supplied and analyzed the sample media.

  8. Vapor and gas sampling of single-shell tank 241-B-202 using the in situ vapor sampling system

    SciTech Connect

    Caprio, G.S.

    1997-08-05

    The Vapor Issue Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-B-202. This document presents In Situ Vapor Sampling System (ISVS) data resulting from the July 18, 1996 sampling of SST 241-B-202. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which supplied and analyzed the sample media.

  9. Vapor and gas sampling of single-shell tank 241-S-106 using the in situ vapor sampling system

    SciTech Connect

    Lockrem, L.L.

    1997-08-05

    The Vapor Issue Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-S-106. This document presents In Situ vapor Sampling System (ISVS) data resulting from the June 13, 1996 sampling of SST 241-S-106. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which`supplied and analyzed the sample media.

  10. Vapor and gas sampling of single-shell tank 241-S-103 using the in situ vapor sampling system

    SciTech Connect

    Lockrem, L.L.

    1997-08-05

    The Vapor Issue Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-S-103. This document presents In Situ Vapor Sampling System (ISVS) data resulting from the June 12, 1996 sampling of SST 241-S-103. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which supplied and analyzed the sample media.

  11. Vapor and gas sampling of single-shell tank 241-S-102 using the in situ vapor sampling system

    SciTech Connect

    Lockrem, L.L.

    1997-08-05

    The Vapor Issue Resolution Program tasked the Vapor Team (the team) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-S-102. This document presents sampling data resulting from the February 11, 1997 sampling of SST 241-S-102. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory which supplied and analyzed the sample media. This is the last in a series of temporal sapling events on SST 241-S-102. The strategy of temporal sampling is to measure the compositional changes of the waste tank headspace as related to seasonal effects and gradual changes of waste chemistry.

  12. Vapor and gas sampling of single-shell tank 241-BX-104 using the in situ vapor sampling system

    SciTech Connect

    Lockrem, L.L.

    1997-08-05

    The Vapor Issue Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-BX-104. This document presents In Situ Vapor Sampling System (ISVS) data resulting from the August 22, 1996 sampling of SST 241-BX-104. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which supplied and analyzed the sample media. This is the first in a series of temporal sampling events on SST 241-BX-104. The strategy of temporal sampling is to measure the compositional changes of the waste tank headspace as related to seasonal effects and gradual changes of waste chemistry.

  13. Single Shell Tank (SST) Program Plan

    SciTech Connect

    HAASS, C.C.

    2000-03-21

    This document provides an initial program plan for retrieval of the single-shell tank waste. Requirements, technical approach, schedule, organization, management, and cost and funding are discussed. The program plan will be refined and updated in fiscal year 2000.

  14. Single Bump on a Shell Fabrication

    SciTech Connect

    Cook, R C

    2004-02-17

    At this morning's fill-tube surrogate working group meeting we tentatively decided on a single bump on a shell for the single March shot. This memo shows the calculations needed as background to fabricate such a bump by depositing an appropriate sized drop of polystyrene solution (i.e. the glue) to a shell as discussed in this mornings meeting. While writing this I had another idea for fabricating a bump, which I quickly outlined at the end of this memo. I am distributing this calculation primarily so that group members can quickly check the calculations and ideas and if without error to provide a framework for initial fabrication efforts.

  15. Gas distribution and starbursts in shell galaxies

    NASA Technical Reports Server (NTRS)

    Weil, Melinda L.; Hernquist, Lars

    1993-01-01

    Detailed maps of most elliptical galaxies reveal that, whereas the greatest part of their luminous mass originates from a smooth distribution with a surface brightness approximated by a de Vaucouleurs law, a small percentage of their light is contributed by low surface brightness distortions termed 'fine structures'. The sharp-edged features called 'shells' are successfully reproduced by merger and infall models involving accretion from less massive companions. In this context, dwarf spheroidal and compact disk galaxies are likely progenitors of these stellar phenomena. However, it is probable that the sources of shell-forming material also contain significant amounts of gas. This component may play an important role in constraining the formation and evolution of shell galaxies. To investigate the effects of the gaseous component, numerical simulations were performed to study the tidal disruption of dwarf galaxies containing both gas and stars by more massive primaries, and the evolution of the ensuing debris. The calculations were performed with a hybrid N-body/hydrodynamics code. Collisionless matter is evolved using a conventional N-body technique and gas is treated using smoothed particle hydrodynamics in which self-gravitating fluid elements are represented as particles evolving according to Lagrangian hydrodynamic equations. An isothermal equation of state is employed so the gas remains at a temperature 104 K. Owing to the large mass ratio between the primary and companion, the primary is modeled as a rigid potential and the self-gravity of both galaxies is neglected.

  16. Single Shell Tank (SST) Retrieval Sequence & Double Shell Tank (DST) Space Evaluation

    SciTech Connect

    HOHL, T.M.

    2001-09-20

    This document describes the baseline single-shell tank (SST) waste retrieval sequence for the River Protection Project updated for Fiscal Year 2002. The double-shell tank (DST) space evaluation presents projected DST needs for Hanford for additional DSTs.

  17. Single Shell Tank (SST) Retrieval Sequence & Double Shell Tank (DST) Space Evaluation

    SciTech Connect

    STRODE, J.N.

    2002-09-23

    This document describes the baseline single-shell tank (SST) waste retrieval sequence for the River Protection Project updated for Fiscal Year 2002. The double-shell tank (DST) space evaluation presents projected DST needs for Hanford for additional DSTs.

  18. Single Shell Tank (SST) Retrieval Sequence and Double Shell Tank (DST) Space Evaluation

    SciTech Connect

    KIRCH, N.W.

    2003-09-23

    This document describes the baseline single-shell tank (SST) waste retrieval sequence for the River Protection Project updated for Fiscal Year 2002. The double-shell tank (DST) space evaluation presents projected DST needs for Hanford for additional DSTs.

  19. Hanford single-shell tank grouping study

    SciTech Connect

    Remund, K.M.; Anderson, C.M.; Simpson, B.C.

    1995-10-01

    A tank grouping study has been conducted to find Hanford single-shell tanks with similar waste properties. The limited sampling resources of the characterization program could be allocated more effectively by having a better understanding of the groups of tanks that have similar waste types. If meaningful groups of tanks can be identified, tank sampling requirements may be reduced, and the uncertainty of the characterization estimates may be narrowed. This tank grouping study considers the analytical sampling information and the historical information that is available for all single-shell tanks. The two primary sources of historical characterization estimates and information come from the Historical Tank Content Estimate (HTCE) Model and the Sort on Radioactive Waste Tanks (SORWT) Model. The sampling and historical information are used together to come up with meaningful groups of similar tanks. Based on the results of analyses presented in this report, credible tank grouping looks very promising. Some groups defined using historical information (HTCE and SORWT) correspond well with those based on analytical data alone.

  20. Preventing Buoyant Displacement Gas Release Events in Hanford Double-Shell Waste Tanks

    SciTech Connect

    Meyer, Perry A.; Stewart, Charles W.

    2001-01-01

    This report summarizes the predictive methods used to ensure that waste transfer operations in Hanford waste tanks do not create waste configurations that lead to unsafe gas release events. The gas release behavior of the waste in existing double-shell tanks has been well characterized, and the flammable gas safety issues associated with safe storage of waste in the current configuration are being formally resolved. However, waste is also being transferred between double-shell tanks and from single-shell tanks into double-shell tanks by saltwell pumping and sluicing that create new wastes and waste configurations that have not been studied as well. Additionally, planning is underway for various waste transfer scenarios to support waste feed delivery to the proposed vitrification plant. It is critical that such waste transfers do not create waste conditions with the potential for dangerous gas release events.

  1. Core-in-shell sorbent for hot coal gas desulfurization

    DOEpatents

    Wheelock, Thomas D.; Akiti, Jr., Tetteh T.

    2004-02-10

    A core-in-shell sorbent is described herein. The core is reactive to the compounds of interest, and is preferably calcium-based, such as limestone for hot gas desulfurization. The shell is a porous protective layer, preferably inert, which allows the reactive core to remove the desired compounds while maintaining the desired physical characteristics to withstand the conditions of use.

  2. Acoustic radiation from single and double ribbed circular cylindrical shells

    NASA Astrophysics Data System (ADS)

    Burroughs, C. B.; Hayek, S. I.; Hallander, J. E.; Bostian, D. A.

    1984-03-01

    Measurements of the acoustic radiation from single and double ribbed circular cylindrical shells were made on the NUSC Transducer Calibration Platform (TCP) in Lake Seneca, NY. Six different types of mechanical drives were used at each of three locations inside the inner shell. Measurements of the shell vibration and acoustic radiation were made with and without outer shells installed around the inner shell structure. For two types of drives, measurements were made with a pressure release layer installed between the inner and outer shell surfaces. Acoustic radiation measurements were made as a function of frequency from 20 to 5,000 Hz and as a function of observation direction at several frequencies for each shell and drive measurement configuration. Measured acoustic radiation data as a function of frequency have been processed. Analysis of the processed data is presented and discussed. It is shown that the location of the drive had a significant effect on the acoustic radiation. The outer shell reduced the acoustic radiation at shell resonant frequencies, but had little effect on other frequencies. The pressure release layer in the double shell had little effect on the acoustic radiation.

  3. Structural Integrity of Single Shell Tanks at Hanford - 9491

    SciTech Connect

    Rinker, Michael W.; Pilli, Siva Prasad; Karri, Naveen K.; Deibler, John E.; Johnson, Kenneth I.; Holbery, James D.; Mullen, O Dennis; Hurley, David E.

    2009-03-01

    The 149 Single Shell Tanks at the Hanford Site were constructed between the 1940’s and the 1960’s. Many of the tanks are either known or suspected to have leaked in the past. While the free liquids have been removed from the tanks, they still contain significant waste volumes. Recently, the tank farm operations contractor established a Single Shell Tank Integrity Program. Structural integrity is one aspect of the program. The structural analysis of the Single Shell Tanks has several challenging factors. There are several tank sizes and configurations that need to be analyzed. Tank capacities range from fifty-five thousand gallons to one-million gallons. The smallest tank type is approximately twenty feet in diameter, and the three other tank types are all seventy-five feet in diameter. Within each tank type there are varying concrete strengths, types of steel, tank floor arrangements, in-tank hardware, riser sizes and locations, and other appurtenances that need to be addressed. Furthermore, soil properties vary throughout the tank farms. The Pacific Northwest National Laboratory has been conducting preliminary structural analyses of the various single shell tank types to address these parameters. The preliminary analyses will assess which aspects of the tanks will require further detailed analysis. Evaluation criteria to which the tanks will be analyzed are also being developed for the Single Shell Tank Integrity Program. This information will be reviewed by the Single Shell Tank Integrity Expert Panel that has been formed to issue recommendations to the DOE and to the tank farm operations contractor regarding Single Shell Tank Integrity. This paper provides a summary of the preliminary analysis of the single shell tanks, a summary of the recommendations for the detailed analyses, and the proposed evaluation criteria by which the tanks will be judged.

  4. Mechanisms of gas bubble retention and release: results for Hanford Waste Tanks 241-S-102 and 241-SY-103 and single-shell tank simulants

    SciTech Connect

    Gauglitz, P.A.; Rassat, S.D.; Bredt, P.R.; Konynenbelt, J.H.; Tingey, S.M.; Mendoza, D.P.

    1996-09-01

    Research at Pacific Northwest National Laboratory (PNNL) has probed the physical mechanisms and waste properties that contribute to the retention and release of flammable gases from radioactive waste stored in underground tanks at Hanford. This study was conducted for Westinghouse Hanford Company as part of the PNNL Flammable Gas Project. The wastes contained in the tanks are mixes of radioactive and chemical products, and some of these wastes are known to generate mixtures of flammable gases, including hydrogen, nitrous oxide, and ammonia. Because these gases are flammable, their retention and episodic release pose a number of safety concerns.

  5. Constraints for system specifications for the double-shell and single-shell tank systems

    SciTech Connect

    SHAW, C.P.

    1999-05-18

    This is a supporting document for the Level 1 Double-Shell and Single-Shell System Specifications. The rationale for selection of specific regulatory constraining documents cited in the two system specifications is provided. many of the regulations have been implemented by the Project Hanford Management Contract procedures (HNF-PROs) and as such noted and traced back to their origins in State and Federal regulations.

  6. Thin-shell wormholes with a generalized Chaplygin gas

    SciTech Connect

    Eiroa, Ernesto F.

    2009-08-15

    In this article, spherically symmetric thin-shell wormholes supported by a generalized Chaplygin gas are constructed and their stability under perturbations preserving the symmetry is studied. Wormholes with charge and with a cosmological constant are analyzed and the results are compared with those obtained for the original Chaplygin gas, which was considered in a previous work. For some values of the parameters, one stable configuration is also present and a new extra unstable solution is found.

  7. Kinematic arguments against single relativistic shell models for GRBs

    NASA Technical Reports Server (NTRS)

    Fenimore, Edward E.; Ramirez, E.; Sumner, M. C.

    1997-01-01

    Two main types of models have been suggested to explain the long durations and multiple peaks of Gamma Ray Bursts (GRBs). In one, there is a very quick release of energy at a central site resulting in a single relativistic shell that produces peaks in the time history through its interactions with the ambient material. In the other, the central site sporadically releases energy over hundreds of seconds forming a peak with each burst of energy. The authors show that the average envelope of emission and the presence of gaps in GRBs are inconsistent with a single relativistic shell. They estimate that the maximum fraction of a single shell that can produce gamma-rays in a GRB with multiple peaks is 10(exp (minus)3), implying that single relativistic shells require 10(exp 3) times more energy than previously thought. They conclude that either the central site of a GRB must produce (approx)10(exp 51) erg/s(exp (minus)1) for hundreds of seconds, or the relativistic shell must have structure on a scales the order of (radical)(epsilon)(Gamma)(exp (minus)1), where (Gamma) is the bulk Lorentz factor ((approximately)10(exp 2) to 10(exp 3)) and (epsilon) is the efficiency.

  8. Hazard assessments of double-shell flammable gas tanks

    SciTech Connect

    Fox, G.L.; Stepnewski, D.D.

    1994-09-28

    This report is the fourth in a series of hazard assessments performed on the double-shell flammable gas watch list tanks. This report focuses on hazards associated with the double-shell watch list tanks (101-AW, 103-AN, 104-AN, and 105-AN). While a similar assessment has already been performed for tank 103-SY, it is also included here to incorporate a more representative slurry gas mixture and provide a consistent basis for comparing results for all the flammable gas tanks. This report is intended to provide an in-depth assessment by considering the details of the gas release event and slurry gas mixing as the gas is released from the waste. The consequences of postulated gas ignition are evaluated using a plume burn model and updated ignition frequency predictions. Tank pressurization which results from a gas burn, along with the structural response, is also considered. The report is intended to support the safety basis for work activities in flammable gas tanks by showing margins to safety limits that are available in the design and procedures.

  9. Overview of Hanford Single Shell Tank (SST) Structural Integrity

    SciTech Connect

    Rast, Richard S.; Washenfelder, Dennis J.; Johnson, Jeremy M.

    2013-11-14

    To improve the understanding of the single-shell tanks (SSTs) integrity, Washington River Protection Solutions, LLC (WRPS), the USDOE Hanford Site tank contractor, developed an enhanced Single-Shell Tank Integrity Project (SSTIP) in 2009. An expert panel on SST integrity, consisting of various subject matters experts in industry and academia, was created to provide recommendations supporting the development of the project. This panel developed 33 recommendations in four main areas of interest: structural integrity, liner degradation, leak integrity and prevention, and mitigation of contamination migration, Seventeen of these recommendations were used to develop the basis for the M-45-10-1 Change Package for the Hanford Federal Agreement and Compliance Order, which is also known as the Tri-Party Agreement. The structural integrity of the tanks is a key element in completing the cleanup mission at the Hanford Site. There are eight primary recommendations related to the structural integrity of Hanford Single-Shell Tanks. Six recommendations are being implemented through current and planned activities. The structural integrity of the Hanford is being evaluated through analysis, monitoring, inspection, materials testing, and construction document review. Structural evaluation in the form of analysis is performed using modern finite element models generated in ANSYS. The analyses consider in-situ, thermal, operating loads and natural phenomena such as earthquakes. Structural analysis of 108 of 149 Hanford Single-Shell Tanks has concluded that the tanks are structurally sound and meet current industry standards. Analysis of the remaining Hanford Single-Shell Tanks is scheduled for FY2014. Hanford Single-Shell Tanks are monitored through a dome deflection program. The program looks for deflections of the tank dome greater than 1/4 inch. No such deflections have been recorded. The tanks are also subjected to visual inspection. Digital cameras record the interior surface of

  10. Single-shell tank leak emergency pumping guide. Revision 5

    SciTech Connect

    Wiggins, D.D.

    1994-10-04

    This document provides general information on all Single-Shell Tank Farms about readiness and special concerns for Emergency Pumping and identifies the required actions when a Single-Shell tank is identified as a leaking tank. Tank Transfer Routes are described, possible heat trace circuits are outlined, and tank riser status and obstructions are documented. Locations of existing saltwell systems and spares, information on emergency pumping equipment, watch list tank status, and transfer line integrity assessments are all included. A matrix of required actions to emergency pump individual tanks, and lists of useful drawings, procedures, work procedure outlines, and references are also provided.

  11. Single-shell tank retrieval program mission analysis report

    SciTech Connect

    Stokes, W.J.

    1998-08-11

    This Mission Analysis Report was prepared to provide the foundation for the Single-Shell Tank (SST) Retrieval Program, a new program responsible for waste removal for the SSTS. The SST Retrieval Program is integrated with other Tank Waste Remediation System activities that provide the management, technical, and operations elements associated with planning and execution of SST and SST Farm retrieval and closure. This Mission Analysis Report provides the basis and strategy for developing a program plan for SST retrieval. This Mission Analysis Report responds to a US Department of Energy request for an alternative single-shell tank retrieval approach (Taylor 1997).

  12. Attempts to Produce D2-Gas-Filled Be Shells

    SciTech Connect

    Cook, B; McElfresh, M; Alford, C; Fought, E; Letts, S

    2005-01-14

    We have attempted to fabricate some 0.5 mm diameter D{sub 2}-gas-filled Be shells by coating gas-filled PVA-coated GDP mandrels with Cu-doped Be. We find that during the coating all (or most) of the gas leaks out. This is likely due to either small cracks or holes in the coating that are formed at the earliest points and are maintained during the thickness build-up of the coating, and/or to some level of intrinsic porosity in the coating. This memo documents our efforts.

  13. Single-photon superradiance and radiation trapping by atomic shells

    NASA Astrophysics Data System (ADS)

    Svidzinsky, Anatoly A.; Li, Fu; Li, Hongyuan; Zhang, Xiwen; Ooi, C. H. Raymond; Scully, Marlan O.

    2016-04-01

    The collective nature of light emission by atomic ensembles yields fascinating effects such as superradiance and radiation trapping even at the single-photon level. Light emission is influenced by virtual transitions and the collective Lamb shift which yields peculiar features in temporal evolution of the atomic system. We study how two-dimensional atomic structures collectively emit a single photon. Namely, we consider spherical, cylindrical, and spheroidal shells with two-level atoms continuously distributed on the shell surface and find exact analytical solutions for eigenstates of such systems and their collective decay rates and frequency shifts. We identify states which undergo superradiant decay and states which are trapped and investigate how size and shape of the shell affects collective light emission. Our findings could be useful for quantum information storage and the design of optical switches.

  14. Single shell tank sluicing history and failure frequency

    SciTech Connect

    HERTZEL, J.S.

    1998-11-10

    This document assesses the potential for failure of the single-shell tanks (SSTs) that are presumably sound and helps to establish the retrieval priorities for these and the assumed leakers. Furthermore, this report examines probabilities of SST failure as a function of age and operational history, and provides a simple statistical summary of historical leak volumes, leak rates, and corrosion factor.

  15. Single-shell tank interim stabilization project plan

    SciTech Connect

    Ross, W.E.

    1998-05-11

    This project plan establishes the management framework for conduct of the TWRS Single-Shell Tank Interim Stabilization completion program. Specifically, this plan defines the mission needs and requirements; technical objectives and approach; organizational structure, roles, responsibilities, and interfaces; and operational methods. This plan serves as the project executional baseline.

  16. Single Shell Tank (SST) Interim Stabilization Project Plan

    SciTech Connect

    VLADIMIROFF, D.T.; BOYLES, V.C.

    2000-05-22

    This project plan establishes the management framework for the conduct of the CHG Single-Shell Tank Interim Stabilization completion program. Specifically, this plan defines the mission needs and requirements; technical objectives and approach; organization structure, roles, responsibilities, and interfaces; and operational methods. This plan serves as the project executional baseline.

  17. Hanford single shell tank saltcake cesium removal test plan

    SciTech Connect

    Duncan, J.B., Westinghouse Hanford

    1996-12-11

    This document provides the test preparation and conduct of a cesium removal test using Hanford Single Shell Tank Saltcake from tanks 241-BY-110, 241-U-108, 241 U 109, 241-A-101, and 241-S-102 in a benchscale column. The cesium sorbent to be tested is crystalline silicotitanate

  18. Enhanced Ethanol Gas Sensing Properties of SnO2-Core/ZnO-Shell Nanostructures

    PubMed Central

    Tharsika, T.; Haseeb, A. S. M. A.; Akbar, Sheikh A.; Sabri, Mohd Faizul Mohd; Hoong, Wong Yew

    2014-01-01

    An inexpensive single-step carbon-assisted thermal evaporation method for the growth of SnO2-core/ZnO-shell nanostructures is described, and the ethanol sensing properties are presented. The structure and phases of the grown nanostructures are investigated by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. XRD analysis indicates that the core-shell nanostructures have good crystallinity. At a lower growth duration of 15 min, only SnO2 nanowires with a rectangular cross-section are observed, while the ZnO shell is observed when the growth time is increased to 30 min. Core-shell hierarchical nanostructures are present for a growth time exceeding 60 min. The growth mechanism for SnO2-core/ZnO-shell nanowires and hierarchical nanostructures are also discussed. The sensitivity of the synthesized SnO2-core/ZnO-shell nanostructures towards ethanol sensing is investigated. Results show that the SnO2-core/ZnO-shell nanostructures deposited at 90 min exhibit enhanced sensitivity to ethanol. The sensitivity of SnO2-core/ZnO-shell nanostructures towards 20 ppm ethanol gas at 400 °C is about ∼5-times that of SnO2 nanowires. This improvement in ethanol gas response is attributed to high active sensing sites and the synergistic effect of the encapsulation of SnO2 by ZnO nanostructures. PMID:25116903

  19. Atomic shell structure from the Single-Exponential Decay Detector

    SciTech Connect

    Silva, Piotr de; Korchowiec, Jacek; Wesolowski, Tomasz A.

    2014-04-28

    The density of atomic systems is analysed via the Single-Exponential Decay Detector (SEDD). SEDD is a scalar field designed to explore mathematical, rather than physical, properties of electron density. Nevertheless, it has been shown that SEDD can serve as a descriptor of bonding patterns in molecules as well as an indicator of atomic shells [P. de Silva, J. Korchowiec, and T. A. Wesolowski, ChemPhysChem 13, 3462 (2012)]. In this work, a more detailed analysis of atomic shells is done for atoms in the Li–Xe series. Shell populations based on SEDD agree with the Aufbau principle even better than those obtained from the Electron Localization Function, which is a popular indicator of electron localization. A link between SEDD and the local wave vector is given, which provides a physical interpretation of SEDD.

  20. Spherical thin-shell wormholes and modified Chaplygin gas

    SciTech Connect

    Sharif, M.; Azam, M. E-mail: azammath@gmail.com

    2013-05-01

    The purpose of this paper is to construct spherical thin-shell wormhole solutions through cut and paste technique and investigate the stability of these solutions in the vicinity of modified Chaplygin gas. The Darmois-Israel formalism is used to formulate the stresses of the surface concentrating the exotic matter. We explore the stability of the wormhole solutions by using the standard potential method. We conclude that there exist more stable as well as unstable solutions than the previous study with generalized Chaplygin gas [19].

  1. Single-shell tank interim stabilization project plan

    SciTech Connect

    Ross, W.E.

    1998-03-27

    Solid and liquid radioactive waste continues to be stored in 149 single-shell tanks at the Hanford Site. To date, 119 tanks have had most of the pumpable liquid removed by interim stabilization. Thirty tanks remain to be stabilized. One of these tanks (C-106) will be stabilized by retrieval of the tank contents. The remaining 29 tanks will be interim stabilized by saltwell pumping. In the summer of 1997, the US Department of Energy (DOE) placed a moratorium on the startup of additional saltwell pumping systems because of funding constraints and proposed modifications to the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) milestones to the Washington State Department of Ecology (Ecology). In a letter dated February 10, 1998, Final Determination Pursuant to Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) in the Matter of the Disapproval of the DOE`s Change Control Form M-41-97-01 (Fitzsimmons 1998), Ecology disapproved the DOE Change Control Form M-41-97-01. In response, Fluor Daniel Hanford, Inc. (FDH) directed Lockheed Martin Hanford Corporation (LNMC) to initiate development of a project plan in a letter dated February 25, 1998, Direction for Development of an Aggressive Single-Shell Tank (SST) Interim Stabilization Completion Project Plan in Support of Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). In a letter dated March 2, 1998, Request for an Aggressive Single-Shell Tank (SST) Interim Stabilization Completion Project Plan, the DOE reaffirmed the need for an aggressive SST interim stabilization completion project plan to support a finalized Tri-Party Agreement Milestone M-41 recovery plan. This project plan establishes the management framework for conduct of the TWRS Single-Shell Tank Interim Stabilization completion program. Specifically, this plan defines the mission needs and requirements; technical objectives and approach; organizational structure, roles, responsibilities

  2. DEVELOPMENT OF ANSYS FINITE ELEMENT MODELS FOR SINGLE SHELL TANK (SST) & DOUBLE SHELL TANK (DST) TANKS

    SciTech Connect

    JULYK, L.J.; MACKEY, T.C.

    2003-06-19

    Summary report of ANSYS finite element models developed for dome load analysis of Hanford 100-series single-shell tanks and double-shell tanks. Document provides user interface for selecting proper tank model and changing of analysis parameters for tank specific analysis. Current dome load restrictions for the Hanford Site underground waste storage tanks are based on existing analyses of record (AOR) that evaluated the tanks for a specific set of design load conditions. However, greater flexibility is required in controlling dome loadings applied to the tanks due to day-to-day operations and waste retrieval activities. This requires the development of an analytical model with sufficient detail to evaluate various dome loading conditions not specifically addressed in the AOR.

  3. A detailed view of the gas shell around R Sculptoris with ALMA

    NASA Astrophysics Data System (ADS)

    Maercker, M.; Vlemmings, W. H. T.; Brunner, M.; De Beck, E.; Humphreys, E. M.; Kerschbaum, F.; Lindqvist, M.; Olofsson, H.; Ramstedt, S.

    2016-02-01

    Context. During the asymptotic giant branch (AGB) phase, stars undergo thermal pulses - short-lived phases of explosive helium burning in a shell around the stellar core. Thermal pulses lead to the formation and mixing-up of new elements to the stellar surface. They are hence fundamental to the chemical evolution of the star and its circumstellar envelope. A further consequence of thermal pulses is the formation of detached shells of gas and dust around the star, several of which have been observed around carbon-rich AGB stars. Aims: We aim to determine the physical properties of the detached gas shell around R Sculptoris, in particular the shell mass and temperature, and to constrain the evolution of the mass-loss rate during and after a thermal pulse. Methods: We analyse 12CO(1-0), 12CO(2-1), and 12CO(3-2) emission, observed with the Atacama Large Millimeter/submillimeter Array (ALMA) during Cycle 0 and complemented by single-dish observations. The spatial resolution of the ALMA data allows us to separate the detached shell emission from the extended emission inside the shell. We perform radiative transfer modelling of both components to determine the shell properties and the post-pulse mass-loss properties. Results: The ALMA data show a gas shell with a radius of 19.̋5 expanding at 14.3 km s-1. The different scales probed by the ALMA Cycle 0 array show that the shell must be entirely filled with gas, contrary to the idea of a detached shell. The comparison to single-dish spectra and radiative transfer modelling confirms this. We derive a shell mass of 4.5 × 10-3 M⊙ with a temperature of 50 K. Typical timescales for thermal pulses imply a pulse mass-loss rate of 2.3 × 10-5 M⊙ yr-1. For the post-pulse mass-loss rate, we find evidence for a gradual decline of the mass-loss rate, with an average value of 1.6 × 10-5 M⊙ yr-1. The total amount of mass lost since the last thermal pulse is 0.03 M⊙, a factor four higher compared to classical models, with a

  4. Single-shell carbon nanotubes imaged by atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Höper, Ralf; Workman, Richard K.; Chen, Dong; Sarid, Dror; Yadav, Tapesh; Withers, James C.; Loutfy, Raouf O.

    1994-05-01

    Single-shell carbon nanotubes, approximately 1 nm in diameter, have been imaged for the first time by atomic force microscopy operating in both the contact and tapping modes. For the contact mode, the height of the imaged nanotubes has been calibrated using the atomic steps of the silicon substrate on which the nanotubes were deposited. For the tapping mode, the calibration was performed using an industry-standard grating. The paper discusses substrate and sample preparation methods for the characterization by scanning probe microscopy of nanotubes deposited on a substrate.

  5. Biomass-based palm shell activated carbon and palm shell carbon molecular sieve as gas separation adsorbents.

    PubMed

    Sethupathi, Sumathi; Bashir, Mohammed Jk; Akbar, Zinatizadeh Ali; Mohamed, Abdul Rahman

    2015-04-01

    Lignocellulosic biomass has been widely recognised as a potential low-cost source for the production of high added value materials and proved to be a good precursor for the production of activated carbons. One of such valuable biomasses used for the production of activated carbons is palm shell. Palm shell (endocarp) is an abundant by-product produced from the palm oil industries throughout tropical countries. Palm shell activated carbon and palm shell carbon molecular sieve has been widely applied in various environmental pollution control technologies, mainly owing to its high adsorption performance, well-developed porosity and low cost, leading to potential applications in gas-phase separation using adsorption processes. This mini-review represents a comprehensive overview of the palm shell activated carbon and palm shell carbon molecular sieve preparation method, physicochemical properties and feasibility of palm shell activated carbon and palm shell carbon molecular sieve in gas separation processes. Some of the limitations are outlined and suggestions for future improvements are pointed out.

  6. Single Step Sintered Calcium Phosphate Fibers from Avian EGG Shell

    NASA Astrophysics Data System (ADS)

    Dadhich, Prabhash; Das, Bodhisatwa; Dhara, Santanu

    2013-11-01

    Different forms of calcium-phosphate (Hydoxyapatite, α-TCP, β-TCP, CDHA) minerals are found to be major component of bone tissue. Development of calcium-phosphate (CaP) based fibrous microstructures is of significant research interest worldwide owing to its improved mechanical properties and higher interconnectivity. Here we represent a method for single step sintered wet-spun Fibers of calcium phosphate from avian egg shells for biomedical applications. Raw egg shell powder was mixed with chitosan solution and Phosphoric acid. The mixture is milled in a ball mill overnight and then filtered. The slurry was de-aired using 100 microliter 1-octanol per 100 ml of slurry as antifoaming and wet spun in coagulation bath. Fiber was dried overnight and sintered at different temperatures for microstructure and phase analysis. Both green and sintered Fibers were physico-chemical characterized by SEM, EDX, XRD, TGA, DSC, FTIR, and stereo-zoom microscopy. The fibers obtained in this procedure are found to have highly porous interconnected structures which can provide good cell adhesion and therefore can be used for bioactive scaffold making.

  7. Assessment groundwater monitoring plan for single shell tank waste management area B-BX-BY

    SciTech Connect

    Caggiano, J.A.

    1996-09-27

    Single Shell Tank Waste Management Area B-BX-BY has been placed into groundwater quality assessment monitoring under interim-status regulations. This document presents background and an assessment groundwater monitoring plan to evaluate any impacts of risks/spills from these Single Shell Tanks in WMA B-BX-BY on groundwater quality.

  8. Does low gas permeability of rigid-shelled gekkotan eggs affect embryonic development?

    PubMed

    Andrews, Robin M; Thompson, Michael B; Greene, Virginia W

    2013-06-01

    Parchment-shelled eggs are characteristic of most squamates, including the basal clades of gekkotan lizards. The majority of gekkotan lizards, however, produce rigid-shelled eggs that are highly impermeable to gas exchange; eggs are laid in dry sites and experience a net loss of water during incubation. We tested the hypothesis that the 1,000-fold lower rate of oxygen diffusion through the shells of rigid- compared to parchment-shelled eggs imposes a physiological cost on development. To do this, we contrasted species with rigid and with parchment shells with regards to (1) rates of embryonic metabolism and (2) rates and patterns of development of the yolk sac and chorioallantois, the vascularized extra-embryonic membranes that transport oxygen to embryonic tissues. Metabolic rates of embryos from the rigid-shelled eggs of Gehyra variegata did not differ from those of the parchment-shelled eggs of Oedura lesueurii. Moreover, maximum metabolic rates of gekkotans with rigid shells did not differ from those of gekkotan or scincid lizards with parchment shells. In contrast, the yolk sac covered more of the surface area of the egg at oviposition, and the chorioallantois reached its full extent earlier for the species with rigid shelled eggs (Chondrodactylus turneri, G. variegata) than for the species with parchment-shelled eggs (Eublepharis macularius, O. lesueurii). Differences in the temporal patterns of yolk sac and chorioallantois development would thus serve to compensate for low rates of oxygen diffusion through rigid shells of gekkotans.

  9. OVERVIEW OF HANFORD SINGLE SHELL TANK (SST) STRUCTURAL INTEGRITY - 12123

    SciTech Connect

    RAST RS; RINKER MW; WASHENFELDER DJ; JOHNSON JB

    2012-01-25

    To improve the understanding of the single-shell tanks (SSTs) integrity, Washington River Protection Solutions, LLC (WRPS), the USDOE Hanford Site tank contractor, developed an enhanced Single-Shell Tank Integrity Project in 2009. An expert panel on SST integrity, consisting of various subject matters experts in industry and academia, was created to provide recommendations supporting the development of the project. This panel developed 33 recommendations in four main areas of interest: structural integrity, liner degradation, leak integrity and prevention, and mitigation of contamination migration. Seventeen of these recommendations were used to develop the basis for the M-45-10-1 Change Package for the Hanford Federal Agreement and Compliance Order, which is also known as the Tri-Party Agreement. The structural integrity of the tanks is a key element in completing the cleanup mission at the Hanford Site. There are eight primary recommendations related to the structural integrity of Hanford SSTs. Six recommendations are being implemented through current and planned activities. The structural integrity of the Hanford SSTs is being evaluated through analysis, monitoring, inspection, materials testing, and construction document review. Structural evaluation in the form of analysis is performed using modern finite element models generated in ANSYS{reg_sign} The analyses consider in-situ, thermal, operating loads and natural phenomena such as earthquakes. Structural analysis of 108 of 149 Hanford SSTs has concluded that the tanks are structurally sound and meet current industry standards. Analyses of the remaining Hanford SSTs are scheduled for FY2013. Hanford SSTs are monitored through a dome deflection program. The program looks for deflections of the tank dome greater than 1/4 inch. No such deflections have been recorded. The tanks are also subjected to visual inspection. Digital cameras record the interior surface of the concrete tank domes, looking for cracks and

  10. Royal Dutch/Shell unit to start gas flow off Brazil

    SciTech Connect

    Not Available

    1992-07-20

    Pecten do Brazil, a unit of the Royal Dutch/Shell Group, plans a September start-up of Merluza, the only natural gas field discovered off Brazil by a foreign operator. This paper reports that plans call for initial production of 17.7 MMcfd from a single fixed platform in 130 m of water in the Santos basin 180 km off Sao Paulo state. Production is expected to build to 53 MMcfd 1 year later and stay at that volume for 12 years. Total investment in the project is pegged at $439 million. Although Pecten discovered and developed the field, stat oil company Petroleos Brasileiro SA earlier was scheduled to assume operator ship in spring 1992. Pecten found Merluza in 1979 and has drilled six high angle development wells. The field holds and estimated 388.5 bcf of reserves, almost 1/10 of the nation's total 4.06 tcf, plus 11 million bbl of condensate. Merluza gas will move though a 186 km, 16 in. subsea pipeline to shore at Praia Grande, Santos, where is will link with a 28 km, 16 in. pipeline to the Presidente Bernardes refinery at Cubatao, Sao Paulo State. The refinery will take some of the gas, with the rest to be distributed in Sao Paulo state by Comgas, the state's gas distribution company.

  11. Discovery of Molecular Gas Shells around the Unusual Galaxy Centaurus A

    NASA Astrophysics Data System (ADS)

    2000-03-01

    avenues for future research on the evolution of galaxies. However, observations like these are very challenging. First of all, as there are comparatively small quantities of gas in most galaxy shells, such measurements require large radio telescopes with high-sensitivity receivers, as well as many hours of observation before sufficiently accurate results (i.e., signal-to-noise ratio) are obtained. In the present case, no less than 20 hours were needed to achieve the secure detection of the emission from CO molecules, as displayed in PR Photo 08b/00 . Moreover, the angular resolution on the sky of the single 15-metre SEST dish is only about 44 arcsec (at the wavelengths of the observed CO lines around 3 mm). This makes it virtually impossible to obtain a clear view of the individual shells in distant galaxies with this telescope. On the other hand, in nearby targets such as Centaurus A, the shells extend over a comparatively large sky area and thus require large-scale mapping, a very time-consuming project. The role of ALMA However, exciting possibilities for more detailed studies, also of much more distant galaxies, are opening with the future Atacama Large Millimeter Array (ALMA) . The collecting area of ALMA is about 7000 m 2 , or over 40 times larger than that of SEST. It will also achieve sub-arcsecond angular resolution when its 64 antennas are combined in the interferometric mode. Together, these properties of ALMA will allow much more sensitive and detailed observations of galaxies at larger distances. When compared to earlier observations of CO near the centre of Centaurus A, the present SEST data show that about 10% of the molecular gas is far outside the centre of this galaxy. As a next step, it would be interesting to examine whether this is also true in other elliptical galaxies with gaseous shells. And will it be possible to detect other molecules in these shells? There will certainly be no lack of opportunities for exciting research in this field, especially

  12. Size Effect of Silica Shell on Gas Uptake Kinetics in Dry Water.

    PubMed

    Li, Yong; Zhang, Diwei; Bai, Dongsheng; Li, Shujing; Wang, Xinrui; Zhou, Wei

    2016-07-26

    Two kinds of dry water (DW) particles are prepared by mixing water and hydrophobic silica particles with nanometer or micrometer dimensions, and the two DW particles are found to have similar size distributions regardless of the size of the silica shell. The CO2 uptake kinetics of DW with nanometer (nanoshell) and micrometer shells (microshell) are measured, and both uptake rate and capacity show the obvious size effect of the silica shell. The DW with a microshell possesses a larger uptake capacity, whereas the DW with a nanoshell has a faster uptake rate. By comparing the uptake kinetics of soluble NH3 and CO2 further, we found that the microshell enhances the stability and the dispersion degree of DW and the nanoshell offers a shorter path for the transit of guest gas into the water core. Furthermore, molecular dynamics simulation is introduced to illustrate the nanosize effect of the silica shell on the initial step of the gas uptake. It is found that the concentration of gas molecules close to the silica shell is higher than that in the bulk water core. With the increase in the size of the silica shell, the amount of CO2 in the silica shell decreases, and it is easier for the gas uptake to reach steady state.

  13. Tank characterization report for Single-Shell Tank T-102

    SciTech Connect

    Remund, K.M.; Hartley, S.A.; Toth, J.J.; Tingey, J.M.; Heasler, P.G.; Ryan, F.M.; Simpson, B.C.

    1994-09-01

    Tank 241-T-102 (hereafter referred to as T-102) is a 530,000 gallon single-shell waste tank located in the 200 West T Tank farm at the Hanford Site. In 1993, two cores were taken from this tank and analysis of the cores was conducted by Battelle`s 325-A Laboratory. Characterization of the waste in this tank was conducted to support Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-44-05. Tank T-102 was constructed in 1943 and put into service in 1945; it is the second tank in a cascade system with Tanks T-101 and T-103. During its process history, Tank T-102 received mostly Metal Waste (MW) from the Bismuth Phosphate Process and Coating Waste (CW) from the REDOX Process via the cascade from Tank T-101 and in transfers from Tank C-102. In 1956, the MW was removed from T-102 by pumping and sluicing`. This tank was declared inactive and retired from service in 1976. In 1981, intrusion prevention and stabilization measures were taken to isolate the waste in T-102. The tank presently contains approximately 121,100 liters (32,000 gallons) of liquid and sludge-like waste. Historically, there are no unreviewed safety issues associated with this tank and none were revealed after reviewing the data from the latest core sampling event in 1993. An extensive set of analytical measurements was performed on the core composites. The major constituents (>0.5 wt%) of the waste are water, aluminum, sodium, iron, and nitrate, ordered from the largest concentration to the smallest. The concentrations and inventories of these and other constituents are given. The results of the chemical analyses have been compared to the dangerous waste codes in the Washington Dangerous Waste Regulations (WAC 173-303).

  14. Single-shell tank closure work plan. Revision A

    SciTech Connect

    1995-06-01

    In January 1994, the Hanford Federal Facility Agreement and Conset Order (Tri-Party Agreement) was amended to reflect a revised strategy for remediation of radioactive waste in underground storage tanks. These amendments include milestones for closure of the single-shell tank (SST) operable units, to be initiated by March 2012 and completed by September 2024. This SST-CWP has been prepared to address the principal topical areas identified in Tri-Party Agreement Milestone M-45-06 (i.e., regulatory pathway, operable unit characterization, waste retrieval, technology development, and a strategy for achieving closure). Chapter 2.0 of this SST-CWP provides a brief description of the environmental setting, SST System, the origin and characteristics of SST waste, and ancillary equipment that will be remediated as part of SST operable unit closure. Appendix 2A provides a description of the hydrogeology of the Hanford Site, including information on the unsaturated sediments (vadose zone) beneath the 200 Areas Plateau. Chapter 3.0 provides a discussion of the laws and regulations applicable to closure of the SST farm operable units. Chapter 4.0 provides a summary description of the ongoing characterization activities that best align with the proposed regulatory pathway for closure. Chapter 5.0 describes aspects of the SST waste retrieval program, including retrieval strategy, technology, and sequence, potential tank leakage during retrieval, and considerations of deployment of subsurface barriers. Chapter 6.0 outlines a proposed strategy for closure. Chapter 7.0 provides a summary of the programs underway or planned to develop technologies to support closure. Ca. 325 refs.

  15. SINGLE-INTERVAL GAS PERMEABILITY ESTIMATION

    EPA Science Inventory

    Single-interval, steady-steady-state gas permeability testing requires estimation of pressure at a screened interval which in turn requires measurement of friction factors as a function of mass flow rate. Friction factors can be obtained by injecting air through a length of pipe...

  16. Functions and requirements for Hanford single-shell tank leakage detection and monitoring

    SciTech Connect

    Iwatate, D.F., Westinghouse Hanford

    1996-07-31

    This document applies the System Engineering process to define the functions and requirements for single shell tank (SST) leakage detection, monitoring and mitigation during the initial SST retrieval sequence.

  17. Tank characterization report for Single-Shell Tank B-111

    SciTech Connect

    Remund, K.M.; Tingey, J.M.; Heasler, P.G.; Toth, J.J.; Ryan, F.M.; Hartley, S.A.; Simpson, D.B.; Simpson, B.C.

    1994-09-01

    Tank 241-B-111 (hereafter referred to as B-111) is a 2,006,300 liter (530,000 gallon) single-shell waste tank located in the 200 East B tank farm at Hanford. Two cores were taken from this tank in 1991 and analysis of the cores was conducted by Battelle`s 325-A Laboratory in 1993. Characterization of the waste in this tank is being done to support Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-44-05. Tank B-111 was constructed in 1943 and put into service in 1945; it is the second tank in a cascade system with Tanks B-110 and B-112. During its process history, B-111 received mostly second-decontamination-cycle waste and fission products waste via the cascade from Tank B-110. This tank was retired from service in 1976, and in 1978 the tank was assumed to have leaked 30,300 liters (8,000 gallons). The tank was interim stabilized and interim isolated in 1985. The tank presently contains approximately 893,400 liters (236,000 gallons) of sludge-like waste and approximately 3,800 liters (1,000 gallons) of supernate. Historically, there are no unreviewed safety issues associated with this tank and none were revealed after reviewing the data from the latest core sampling event in 1991. An extensive set of analytical measurements was performed on the core composites. The major constituents (> 0.5 wt%) measured in the waste are water, sodium, nitrate, phosphate, nitrite, bismuth, iron, sulfate and silicon, ordered from largest concentration to the smallest. The concentrations and inventories of these and other constituents are given. Since Tanks B-110 and B-111 have similar process histories, their sampling results were compared. The results of the chemical analyses have been compared to the dangerous waste codes in the Washington Dangerous Waste Regulations (WAC 173-303). This assessment was conducted by comparing tank analyses against dangerous waste characteristics `D` waste codes; and against state waste codes.

  18. Review of technologies for the pretreatment of retrieved single-shell tank waste at Hanford

    SciTech Connect

    Gerber, M.A.

    1992-08-01

    The purpose of the study reported here was to identify and evaluate innovative processes that could be used to pretreat mixed waste retrieved from the 149 single-shell tanks (SSTs) on the US Department of Energy`s (DOE) Hanford site. The information was collected as part of the Single Shell Tank Waste Treatment project at Pacific Northwest Laboratory (PNL). The project is being conducted for Westinghouse Hanford Company under their SST Disposal Program.

  19. Review of technologies for the pretreatment of retrieved single-shell tank waste at Hanford

    SciTech Connect

    Gerber, M.A.

    1992-08-01

    The purpose of the study reported here was to identify and evaluate innovative processes that could be used to pretreat mixed waste retrieved from the 149 single-shell tanks (SSTs) on the US Department of Energy's (DOE) Hanford site. The information was collected as part of the Single Shell Tank Waste Treatment project at Pacific Northwest Laboratory (PNL). The project is being conducted for Westinghouse Hanford Company under their SST Disposal Program.

  20. Integral Hot Gas Pressure Forming of an AA2219 Aluminum Alloy Ellipsoidal Shell

    NASA Astrophysics Data System (ADS)

    Yuan, S. J.; Zhang, R.; Zhang, W. W.

    2017-02-01

    To overcome the poor plastic deformation performance of AA2219 aluminum alloy sheet and its weld seam at room temperature, an integral hot gas pressure forming (IHGPF) process for a combined welded ellipsoidal shell was proposed. A simulation of the IHGPF process was conducted to analyze the axis length variation and thickness distribution during the forming process of the combined welded ellipsoidal shell at elevated temperature. The results demonstrated that lengths of the short and long axes were 150 mm and 220 mm, respectively, and that maximum wall thinning occurred at the pole. Furthermore, an experiment was conducted using IHGPF, and the forming accuracy was measured by three-dimensional video technology. A sound ellipsoidal shell with final axis length ratio of 1.5 was obtained with a shell diameter accuracy of more than 99.3%. It was experimentally proven that an aluminum alloy ellipsoidal shell can be formed using the proposed IHGPF technology.

  1. NIF Double Shell outer-shell experiments

    NASA Astrophysics Data System (ADS)

    Merritt, E. C.; Montgomery, D. S.; Kline, J. L.; Daughton, W. S.; Wilson, D. C.; Dodd, E. S.; Renner, D. B.; Cardenas, T.; Batha, S. H.

    2016-10-01

    At the core of the Double Shell concept is the kinetic energy transfer from the outer shell to the inner shell via collision. This collision sets both the implosion shape of the inner shell, from imprinting of the shape of the outer shell, as well as the maximum energy available to compress the DT fuel. Therefore, it is crucial to be able to control the time-dependent shape of the outer shell, such that the outer shell is nominally round at the collision time. We present the experiment results from our sub-scale ( 1 MJ) NIF outer-shell only shape tuning campaign, where we vary shape by changing a turn-on time delay between the same pulse shape on the inner and outer cone beams. This type of shape tuning is unique to this platform and only possible since the Double Shell design uses a single-shock drive (4.5 ns reverse ramp pulse). The outer-shell only targets used a 5.75 mm diameter standard near-vacuum NIF hohlraum with 0.032 mg/cc He gas fill, and a Be capsule with 0.4% uniform Cu dopant, with 242 um thick ablator. We also present results from a third outer-shell only shot used to measure shell trajectory, which is critical in determining the shell impact time. This work conducted under the auspices of the U.S. DOE by LANL under contract DE-AC52-06NA25396.

  2. Reconstruction of single-shell states for mid-heavy Sn isotopes

    NASA Astrophysics Data System (ADS)

    Dikmen, Erdal; Ozturk, Oguz

    2015-10-01

    A great exact truncation to construct single-shell states for the shell model description of mid-heavy Sn isotopes is offered in the framework of the Drexel University shell model approach. It is based on the occurrence of only one-column Young diagrams in building the multi-shell model states [1]. This truncation allows us to calculate the coefficient of fractional parentage (CFP) for the most stable Sn isotopes, e.g., 116 , 118 , 120Sn, by reducing the calculation requirements. An application to 116 , 118 , 120Sn isotopes in the sdgh-shell is presented. This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) under Contract No. 114F333 and Suleyman Demirel University SDUBAP No. 4166-D2-14.

  3. Gas retention and release behavior in Hanford double-shell waste tanks

    SciTech Connect

    Meyer, P.A.; Brewster, M.E.; Bryan, S.A.

    1997-05-01

    This report describes the current understanding of flammable gas retention and release in Hanford double-shell waste tanks AN-103, AN-104, AN-105, AW-101, SY-101, and SY-103. This knowledge is based on analyses, experimental results, and observations of tank behavior. The applicable data available from the void fraction instrument, retained gas sampler, ball rheometer, tank characterization, and field monitoring are summarized. Retained gas volumes and void fractions are updated with these new data. Using the retained gas compositions from the retained gas sampler, peak dome pressures during a gas burn are calculated as a function of the fraction of retained gas hypothetically released instantaneously into the tank head space. Models and criteria are given for gas generation, initiation of buoyant displacement, and resulting gas release; and predictions are compared with observed tank behavior.

  4. Partial conservation law in a schematic single j shell model

    NASA Astrophysics Data System (ADS)

    Pereira, Wesley; Garcia, Ricardo; Zamick, Larry; Escuderos, Alberto; Neergård, Kai

    We report the discovery of a partial conservation law obeyed by a schematic Hamiltonian of two protons and two neutrons in a j shell. In our Hamiltonian, the interaction matrix element of two nucleons with combined angular momentum J is linear in J for even J and constant for odd J. It turns out that in some stationary states, the sum of the angular momenta Jp and Jn of the proton and neutron pairs is conserved. The energies of these states are given by a linear function of Jp + Jn. The systematics of their occurrence is described and explained.

  5. The argonaut shell: gas-mediated buoyancy control in a pelagic octopus.

    PubMed

    Finn, Julian K; Norman, Mark D

    2010-10-07

    Argonauts (Cephalopoda: Argonautidae) are a group of rarely encountered open-ocean pelagic octopuses with benthic ancestry. Female argonauts inhabit a brittle 'paper nautilus' shell, the role of which has puzzled naturalists for millennia. The primary role attributed to the shell has been as a receptacle for egg deposition and brooding. Our observations of wild argonauts have revealed that the thin calcareous shell also functions as a hydrostatic structure, employed by the female argonaut to precisely control buoyancy at varying depths. Female argonauts use the shell to 'gulp' a measured volume of air at the sea surface, seal off the captured gas using flanged arms and forcefully dive to a depth where the compressed gas buoyancy counteracts body weight. This process allows the female argonaut to attain neutral buoyancy at depth and potentially adjust buoyancy to counter the increased (and significant) weight of eggs during reproductive periods. Evolution of this air-capture strategy enables this negatively buoyant octopus to survive free of the sea floor. This major shift in life mode from benthic to pelagic shows strong evolutionary parallels with the origins of all cephalopods, which attained gas-mediated buoyancy via the closed-chambered shells of the true nautiluses and their relatives.

  6. The argonaut shell: gas-mediated buoyancy control in a pelagic octopus

    PubMed Central

    Finn, Julian K.; Norman, Mark D.

    2010-01-01

    Argonauts (Cephalopoda: Argonautidae) are a group of rarely encountered open-ocean pelagic octopuses with benthic ancestry. Female argonauts inhabit a brittle ‘paper nautilus’ shell, the role of which has puzzled naturalists for millennia. The primary role attributed to the shell has been as a receptacle for egg deposition and brooding. Our observations of wild argonauts have revealed that the thin calcareous shell also functions as a hydrostatic structure, employed by the female argonaut to precisely control buoyancy at varying depths. Female argonauts use the shell to ‘gulp’ a measured volume of air at the sea surface, seal off the captured gas using flanged arms and forcefully dive to a depth where the compressed gas buoyancy counteracts body weight. This process allows the female argonaut to attain neutral buoyancy at depth and potentially adjust buoyancy to counter the increased (and significant) weight of eggs during reproductive periods. Evolution of this air-capture strategy enables this negatively buoyant octopus to survive free of the sea floor. This major shift in life mode from benthic to pelagic shows strong evolutionary parallels with the origins of all cephalopods, which attained gas-mediated buoyancy via the closed-chambered shells of the true nautiluses and their relatives. PMID:20484241

  7. Gas hydrate single-crystal structure analyses.

    PubMed

    Kirchner, Michael T; Boese, Roland; Billups, W Edward; Norman, Lewis R

    2004-08-04

    The first single-crystal diffraction studies on methane, propane, methane/propane, and adamantane gas hydrates SI, SII, and SH have been performed. To circumvent the problem of very slow crystal growth, a novel technique of in situ cocrystallization of gases and liquids resulting in oligocrystalline material in a capillary has been developed. With special data treatment, termed oligo diffractometry, structural data of the gas hydrates of methane, acetylene, propane, a propane/ethanol/methane-mixture and an adamantane/methane-mixture were obtained. Cell parameters are in accord with reported values. Host network and guest are subject to extensive disorder, reducing the reliability of structural information. It was found that most cages are fully occupied by a guest molecule with the exception of the dodecahedral cage in the acetylene hydrate which is only filled to 60%. For adamantane in the icosahedral cage a disordered model is proposed.

  8. The Beta Pictoris Phenomenon in A-Shell Stars: Detection of Accreting Gas

    NASA Technical Reports Server (NTRS)

    Grady, C. A.; Perez, Mario R.; Talavera, A.; McCollum, B.; Rawley, L. A.; England, M. N.; Schlegel, M.

    1996-01-01

    We present the results of an expanded survey of A-shell stars using IUE high-dispersion spectra and find accreting, circumstellar gas in the line of sight to nine stars, in addition to the previously identified beta Pic, HR 10, and 131 Tau, which can be followed to between +70 and 100 km/s relative to the star. Two of the program stars, HD 88195 and HD 148283, show variable high-velocity gas. Given the small number of IUE spectra for our program stars, detection of high-velocity, accreting gas in 2/3 of the A-shell stars sampled indicates that accretion is an intrinsic part of the A-shell phenomenon and that beta Pic is not unique among main-sequence A stars in exhibiting such activity. Our program stars, as a group, have smaller column densities of high-velocity gas and smaller near-IR excesses compared with beta Pic. These features are consistent with greater central clearing of a remnant debris disk, compared with beta Pic, and suggest that the majority of field A-shell stars are older than beta Pic.

  9. Single-neutron levels near the N=82 shell closure

    SciTech Connect

    Manning, B.; Cizewski, J. A.; Howard, M. E.; O'Malley, P. D.; Ratkiewicz, A.; Kozub, R. L.; Ahn, S.; Jones, K. L.; Allmond, J. M.; Bardayan, D. W.; Beene, J. R.; Liang, J. F.; Nesaraja, C. D.; Pain, S. D.; Pittman, S. T.; Radford, D. C.; Schmitt, K. T.; Shapira, D.; Smith, M. S.; Chae, K. Y.; and others

    2013-04-19

    The (d, p) reaction was measured with the radioactive ion beams of {sup 126}Sn and {sup 128}Sn in inverse kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory, utilizing the Super ORRUBA silicon detector array. Angular distributions of reaction protons were measured for several states in {sup 127}Sn and {sup 129}Sn to determine angular momentum transfers and deduce spectroscopic factors. Such information is critical for calculating direct (n,{gamma}) cross sections for the r-process as well as for constraining shell model parameters in the A Almost-Equal-To 130 region. Combined with previous experiments on {sup 130}Sn and {sup 132}Sn, these results will provide a complete set of (d, p) reaction data on even tin isotopes between stable {sup 124}Sn and doubly-magic {sup 132}Sn.

  10. Development of a mechanical based system for dry retrieval of single-shell tank waste at Hanford

    SciTech Connect

    Ximena Prugue

    2013-07-01

    This study explores the development of a mechanical based system to retrieve single-shell tank waste at the Hanford site, located in Richland, Washington, without the addition of water. Out of 177 tanks at Hanford, there are 149 single-shell tanks (SST) and 28 double-shell tanks (DST). There are currently 67 SSTs that have leaked radioactive waste to the surrounding groundwater in the past or assumed to have questionable tank integrity. Leaking tanks continue to be a major concern as it was recently announced in February 2013 that six SSTs are leaking, even though they were believed to have been stabilized back in 2005. There are also several tanks with significant in-tank obstructions, such as air-lift circulators, where an arm-based retrieval would not be possible. All current methods of waste retrieval deployed involve the addition of significant amounts of water to generate a slurry that can be pumped out of the tank. This water, however, can exacerbate the leak and risk the potential of leaking more waste into the surrounding soil, subsequently contaminating the groundwater. It also reduces available waste storage space in DSTs, and increases the risk of dangerous buoyant displacement gas release events (BDGRE) in the headspace of DSTs. Focusing on leaking tanks, tanks with significant in-tank obstructions, and utilizing existing risers in Hanford's tanks, this study evaluates commercially available dry technologies, such as augers and high-powered vacuums, for feasibility, safety, and efficiency of waste retrieval at Hanford. (authors)

  11. Preliminary design requirements document for the initial single-shell tank retrieval system

    SciTech Connect

    Hertzel, J.S., Westinghouse Hanford

    1996-07-24

    The scope of this Preliminary Design Requirements Document is to identify and define the functions, with associated requirements, which must be performed to demonstrate and accomplish the initial single-shell tank saltcake retrieval from selected tanks. This document sets forth functions, requirements, performance requirements and design constraints necessary to begin conceptual design for the Initial Single-shell Tank Retrieval System. System and physical interfaces between the Initial Single-shell Tank Retrieval System project and the Tank Waste Remediation are identified. The constraints, performance requirements, and transfer of information and data across a technical interface will be documented in an Interface Control Document. The design requirements provided in this document will be augmented by additional detailed design to be documented by the project.

  12. A Survey of Vapors in the Headspaces of Single-Shell Waste Tanks

    SciTech Connect

    Stock, Leon M.; Huckaby, James L.

    2000-10-31

    This report summarizes data on the organic vapors in the single-shell high level radioactive waste tanks at the Hanford site to support a forthcoming toxicological study. All data were obtained from the Tank Characterization Database (PNNL 1999). The TCD contains virtually all the available tank headspace characterization data from 1992 to the present, and includes data for 109 different single-shell waste tanks. Each single-shell tank farm and all major waste types are represented. Descriptions of the sampling and analysis methods have been given elsewhere (Huckaby et al. 1995, Huckaby et al. 1996), and references for specific data are available in the TCD. This is a revision of a report with the same title issued on March 1, 2000 (Stock and Huckaby 2000).

  13. Preparation of highly dispersed core/shell-type titania nanocapsules containing a single Ag nanoparticle.

    PubMed

    Sakai, Hideki; Kanda, Takashi; Shibata, Hirobumi; Ohkubo, Takahiro; Abe, Masahiko

    2006-04-19

    Core/shell-type titania nanocapsules containing a single Ag nanoparticle were prepared. Ag nanoparticles were prepared using the reduction of silver nitrate with hydrazine in the presence of cetyltrimethylammonium bromide (CTAB) as protective agent. The sol-gel reaction of titanium tetraisopropoxide (TTIP) was used to prepare core/shell-type titania nanocapsules with CTAB-coated Ag nanoparticles as the core. TEM observations revealed that the size of the core (Ag particle) and the thickness of the shell (titania) of the core/shell particles obtained are about 10 nm and 5-10 nm, respectively. In addition, the nanocapsules were found to be dispersed in the medium as individual particles without aggregation. Moreover, titania coating caused the surface plasmon absorption of Ag nanoparticles to shift toward the longer wavelength side.

  14. Single-photon double K-shell ionization of low-Z atoms

    NASA Astrophysics Data System (ADS)

    Hoszowska, J.; Kheifets, A. S.; Dousse, J.-Cl; Bray, I.; Cao, W.; Fennane, K.; Kayser, Y.; Kavčič, M.; Szlachetko, J.; Szlachetko, M.

    2010-02-01

    The photon energy dependence of the double K-shell ionization of light atoms is reported. Experimental double-to-single photoionization cross section ratios for Mg, Al, Si and Ca were obtained from measurements of high-resolution x-ray emission spectra. The double photoionization (DPI) cross-sections for K-shell hollow atom production are compared to convergent close-coupling calculations (CCC) for neutral atoms and He-like ions. The relative importance of the initial-state and final-state electron-electron interactions to the K-shell DPI in many-electron atoms and two-electron ions is addressed. Physical mechanisms and scaling laws of the K-shell double photoionization are examined. A semiempirical universal scaling of the DPI cross sections with the effective nuclear charge for neutral atoms 2<=Z<=47 is established.

  15. Test procedures and instructions for single shell tank saltcake cesium removal with crystalline silicotitanate

    SciTech Connect

    Duncan, J.B.

    1997-01-07

    This document provides specific test procedures and instructions to implement the test plan for the preparation and conduct of a cesium removal test, using Hanford Single Shell Tank Saltcake from tanks 24 t -BY- I 10, 24 1 -U- 108, 24 1 -U- 109, 24 1 -A- I 0 1, and 24 t - S-102, in a bench-scale column. The cesium sorbent to be tested is crystalline siticotitanate. The test plan for which this provides instructions is WHC-SD-RE-TP-024, Hanford Single Shell Tank Saltcake Cesium Removal Test Plan.

  16. Static internal pressure capacity of Hanford Single-Shell Waste Tanks

    SciTech Connect

    Julyk, L.J.

    1994-07-19

    Underground single-shell waste storage tanks located at the Hanford Site in Richland, Washington, generate gaseous mixtures that could be ignited, challenging the structural integrity of the tanks. The structural capacity of the single-shell tanks to internal pressure is estimated through nonlinear finite-element structural analyses of the reinforced concrete tank. To determine their internal pressure capacity, designs for both the million-gallon and the half-million-gallon tank are evaluated on the basis of gross structural instability.

  17. Fifth Single-Shell Tank Integrity Project Expert Panel Meeting August 28-29, 2014

    SciTech Connect

    Martin, Todd M.; Boomer, Kayle D.

    2015-01-07

    On August 28th and 29th, 2014 the Single-Shell Tank Integrity Project (SSTIP) Expert Panel (Panel) convened in Richland, Washington. This was the Panel’s first meeting since 2011 and, as a result, was focused primarily on updating the Panel on progress in response to the past recommendations (Single-Shell Tank Integrity Expert Panel Report, RPP-RPT-45921, Rev 0, May 2010). This letter documents the Panel’s discussions and feedback on Phase I activities and results.

  18. Optimization of microporous palm shell activated carbon production for flue gas desulphurization: experimental and statistical studies.

    PubMed

    Sumathi, S; Bhatia, S; Lee, K T; Mohamed, A R

    2009-02-01

    Optimizing the production of microporous activated carbon from waste palm shell was done by applying experimental design methodology. The product, palm shell activated carbon was tested for removal of SO2 gas from flue gas. The activated carbon production was mathematically described as a function of parameters such as flow rate, activation time and activation temperature of carbonization. These parameters were modeled using response surface methodology. The experiments were carried out as a central composite design consisting of 32 experiments. Quadratic models were developed for surface area, total pore volume, and microporosity in term of micropore fraction. The models were used to obtain the optimum process condition for the production of microporous palm shell activated carbon useful for SO2 removal. The optimized palm shell activated carbon with surface area of 973 m(2)/g, total pore volume of 0.78 cc/g and micropore fraction of 70.5% showed an excellent agreement with the amount predicted by the statistical analysis. Palm shell activated carbon with higher surface area and microporosity fraction showed good adsorption affinity for SO2 removal.

  19. The scale dependence of single-nucleon shell structure

    SciTech Connect

    Somà, V.; Hergert, H.; Holt, J. D.

    2015-10-15

    We address the scale dependence of (effective) single-particle energies, non-observable quantities that are commonly used for interpreting nuclear structure observables measured in experiments and computed in many-body theories. We first demonstrate their scale dependence on a formal level, making them intrinsically theoretical objects, before illustrating this point via ab initio calculations in the oxygen isotopes. Finally, we consider a modified definition of effective single-particle energy and investigate its running properties.

  20. Mechanistic analysis of double-shell tank gas release

    SciTech Connect

    Allemann, R.T.; Antoniak, Z.I.; Friley, J.R.; Haines, C.E.; Liljegren, L.M.; Somasundaram, S.

    1991-12-01

    Pacific Northwest Laboratory (PNL) is studying possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at Hanford. This study is being conducted for Westinghouse Hanford Company (WHC), a contractor for the US Department of Energy (DOE). This interim report discusses the work done through November 1990. Safe management of the wastes at Hanford depends on an understanding of the chemical and physical mechanisms that take place in the waste tanks. An example of the need to understand these mechanisms is tank 101-SY. The waste in this tank is generating and periodically releasing potentially flammable gases into the tank vent system according to observations of the tank. How these gases are generated and become trapped, the causes of periodic release, and the mechanism of the release are not known in detail. In order to develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood.

  1. Quadrupole deformation of electron shells in the lattice dynamics of compressed rare-gas crystals

    NASA Astrophysics Data System (ADS)

    Troitskaya, E. P.; Chabanenko, Val. V.; Zhikharev, I. V.; Gorbenko, Ie. Ie.; Pilipenko, E. A.

    2012-06-01

    The lattice dynamics of rare-gas crystals has been constructed taking into account the deformation of electron shells of the atoms of the dipole and quadrupole types, depending on the displacement of the nuclei. The obtained equations of lattice vibrations have been investigated in the long-wavelength approximation. The role played by the three-body interaction and the deformation of the electron shells in the violation of the Cauchy relation has been discussed. The calculated Birch elastic moduli for Xe and deviations from the Cauchy relation are in good agreement with the available experimental data over a wide range of pressures.

  2. Data Observations on Double Shell Tank (DST) Flammable Gas Watch List Tank Behavior

    SciTech Connect

    HEDENGREN, D.C.

    2000-09-28

    This report provides the data from the retained gas sampler, void fraction instrument, ball rheometer, standard hydrogen monitoring system, and other tank data pertinent to gas retention and release behavior in the waste stored in double-shelled Flammable Gas Watch List tanks at Hanford. These include tanks 241-AN-103,241-AN-104, 241-AN-105, 241-AW-101, 241-SY-101, and 241-SY-103. The tanks and the waste they contain are described in terms of fill history and chemistry. The results of mixer pump operation and recent waste transfers and back-dilution in SY-101 are also described. In-situ measurement and monitoring systems are described and the data are summarized under the categories of thermal behavior, waste configuration and properties, gas generation and composition, gas retention and historical gas release behavior.

  3. Assessment of single-shell tank residual-liquid issues at Hanford Site, Washington

    SciTech Connect

    Murthy, K.S.; Stout, L.A.; Napier, B.A.; Reisenauer, A.E.; Landstrom, D.K.

    1983-06-01

    This report provides an assessment of the overall effectiveness and implications of jet pumping the interstitial liquids (IL) from single-shell tanks at Hanford. The jet-pumping program, currently in progress at Hanford, involves the planned removal of IL contained in 89 of the 149 single-shell tanks and its transfer to double-shell tanks after volume reduction by evaporation. The purpose of this report is to estimate the public and worker doses associated with (1) terminating pumping immediately, (2) pumping to a 100,000-gal limit per tank, (3) pumping to a 50,000-gal limit per tank, and (4) pumping to the maximum practical liquid removal level of 30,000 gal. Assessment of the cost-effectiveness of these various levels of pumping in minimizing any undue health and safety risks to the public or worker is also presented.

  4. Geology Data Package for the Single-Shell Tank Waste Management Areas at the Hanford Site

    SciTech Connect

    Reidel, Stephen P.; Chamness, Mickie A.

    2007-12-14

    This data package discusses the geology of the single-shell tank (SST) farms and the geologic history of the area. The purpose of this report is to provide the most recent geologic information available for the SST farms. This report builds upon previous reports on the tank farm geology and Integrated Disposal Facility geology with information available after those reports were published.

  5. Geology Data Package for the Single-Shell Tank Waste Management Areas at the Hanford Site

    SciTech Connect

    Reidel, Steve P.; Chamness, Mickie A.

    2007-01-01

    This data package discusses the geology of the single-shell tank (SST) farms and the geologic history of the area. The focus of this report is to provide the most recent geologic information available for the SST farms. This report builds upon previous reports on the tank farm geology and Integrated Disposal Facility geology with information available after those reports were published.

  6. Assessment of vadose zone radionuclide contamination around Single Shell Tank 241-C-103

    SciTech Connect

    Kos, S.E.

    1995-12-01

    Five drywells surrounding single shell tank 241-C-103 were logged with the high-purity germanium logging system to investigate possible leakage of radioactive contamination from the tank. The investigation included integration of the drywell survey results with several other data sources. There is no conclusive evidence showing indications that the 241-C-103 tank has leaked

  7. Preliminary tank characterization report for single-shell tank 241-BY-101: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-BY-101 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  8. Preliminary tank characterization report for single-shell tank 241-TX-115: Best-Basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-115 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  9. Preliminary tank characterization report for single-shell tank 241-T-203: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-T-203 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  10. Preliminary tank characterization report for single-shell tank 241-c-102: best-basis inventory

    SciTech Connect

    Lambert, S.L.

    1997-08-26

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-C-102 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  11. Preliminary tank characterization report for single-shell tank 241-TY-101: best-basis inventory

    SciTech Connect

    Lambert, S.L.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TY-101 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  12. Preliminary tank characterization report for single-shell tank 241-TX-116: best-basis inventory

    SciTech Connect

    Place, D.E.

    1997-06-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-116 was performed, and a bost-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  13. Preliminary tank characterization report for single-shell tank 241-T-204: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-T-204 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  14. Preliminary tank characterization report for single-shell tank 241-TX-104: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-104 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  15. Preliminary tank characterization report for single-shell tank 241-SX-106: Best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-29

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-SX-106 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  16. Preliminary tank characterization report for single-shell tank 241-S-106: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an . evaluation of available information for single-shell tank 241-S-106 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  17. Preliminary tank characterization report for single-shell tank 241-TX-105: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-105 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  18. Preliminary tank characterization report for single-shell tank 241-A-103: best-basis inventory

    SciTech Connect

    Higley, B.A.

    1997-07-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-A-103 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  19. Preliminary tank characterization report for single-shell tank 241-U-101: Best-Basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-U-101 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  20. Preliminary tank characterization report for single-shell tank 241-SX-105: Best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-29

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-SX-105 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  1. Preliminary tank characterization report for single-shell tank 241-BX-102: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-BX-102 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  2. Preliminary tank characterization report for single-shell tank241-T-202: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-T-202 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  3. Preliminary tank characterization report for single-shell tank 241-TX-117: best-basis inventory

    SciTech Connect

    Place, D.E.

    1997-06-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-117 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  4. Preliminary tank characterization report for single-shell tank 241-SX-107: Best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-29

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-SX-107 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  5. Preliminary tank characterization report for single-shell tank 241-A-104: best basis inventory

    SciTech Connect

    Hodgson, K.M.

    1997-07-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-A-104 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  6. Preliminary tank characterization report for single-shell tank 241-TX-110: Best-basis inventory

    SciTech Connect

    Place, D.E.

    1997-08-26

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-110 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  7. Preliminary tank characterization report for single-shell tank 241-T-103: best-basis inventory

    SciTech Connect

    Lambert, S.L.

    1997-08-26

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-T-103 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  8. Preliminary tank characterization report for single-shell tank 241-T-201: Best-basis inventory

    SciTech Connect

    Field, J.G.; Winward, R.T.

    1997-06-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-T-201 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  9. Preliminary tank characterization report for single-shell tank 241-BY-109: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-BY-109 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  10. Preliminary tank characterization report for single-shell tank 241-BX-111: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-29

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-BX-111 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  11. Preliminary tank characterization report for single-shell tank 241-TX-109: best-basis inventory

    SciTech Connect

    Place, D.E.

    1997-08-26

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-109 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  12. Preliminary tank characterization report for single-shell tank 241-U-103: best-basis inventory

    SciTech Connect

    Kupfer, M.J.; Stout, R.E.; Winward, R.T.

    1997-06-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-U-103 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  13. Preliminary tank characterization report for single-shell tank 241-TX-102: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-102 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  14. Engineering report single-shell tank farms interim measures to limit infiltration through the vadose zone

    SciTech Connect

    HAASS, C.C.

    1999-10-14

    Identifies, evaluates and recommends interim measures for reducing or eliminating water sources and preferential pathways within the vadose zone of the single-shell tank farms. Features studied: surface water infiltration and leaking water lines that provide recharge moisture, and wells that could provide pathways for contaminant migration. An extensive data base, maps, recommended mitigations, and rough order of magnitude costs are included.

  15. Nonpolar InGaN/GaN Core-Shell Single Nanowire Lasers.

    PubMed

    Li, Changyi; Wright, Jeremy B; Liu, Sheng; Lu, Ping; Figiel, Jeffrey J; Leung, Benjamin; Chow, Weng W; Brener, Igal; Koleske, Daniel D; Luk, Ting-Shan; Feezell, Daniel F; Brueck, S R J; Wang, George T

    2017-02-08

    We report lasing from nonpolar p-i-n InGaN/GaN multi-quantum well core-shell single-nanowire lasers by optical pumping at room temperature. The nanowire lasers were fabricated using a hybrid approach consisting of a top-down two-step etch process followed by a bottom-up regrowth process, enabling precise geometrical control and high material gain and optical confinement. The modal gain spectra and the gain curves of the core-shell nanowire lasers were measured using micro-photoluminescence and analyzed using the Hakki-Paoli method. Significantly lower lasing thresholds due to high optical gain were measured compared to previously reported semipolar InGaN/GaN core-shell nanowires, despite significantly shorter cavity lengths and reduced active region volume. Mode simulations show that due to the core-shell architecture, annular-shaped modes have higher optical confinement than solid transverse modes. The results show the viability of this p-i-n nonpolar core-shell nanowire architecture, previously investigated for next-generation light-emitting diodes, as low-threshold, coherent UV-visible nanoscale light emitters, and open a route toward monolithic, integrable, electrically injected single-nanowire lasers operating at room temperature.

  16. Demonstration of Enabling Spar-Shell Cooling Technology in Gas Turbines

    SciTech Connect

    Downs, James

    2014-12-29

    In this Advanced Turbine Program-funded Phase III project, Florida Turbine Technologies, Inc. (FTT) has developed and tested, at a pre-commercial prototypescale, spar-shell turbine airfoils in a commercial gas turbine. The airfoil development is based upon FTT’s research and development to date in Phases I and II of Small Business Innovative Research (SBIR) grants. During this program, FTT has partnered with an Original Equipment Manufacturer (OEM), Siemens Energy, to produce sparshell turbine components for the first pre-commercial prototype test in an F-Class industrial gas turbine engine and has successfully completed validation testing. This project will further the commercialization of this new technology in F-frame and other highly cooled turbine airfoil applications. FTT, in cooperation with Siemens, intends to offer the spar-shell vane as a first-tier supplier for retrofit applications and new large frame industrial gas turbines. The market for the spar-shell vane for these machines is huge. According to Forecast International, 3,211 new gas turbines units (in the >50MW capacity size range) will be ordered in ten years from 2007 to 2016. FTT intends to enter the market in a low rate initial production. After one year of successful extended use, FTT will quickly ramp up production and sales, with a target to capture 1% of the market within the first year and 10% within 5 years (2020).

  17. Infrared and X-Ray Spectroscopy of the Kes 75 Supernova Shell Characterizing the Dust and Gas Properties

    NASA Technical Reports Server (NTRS)

    Temim, Tea; Arendt, Richard G.; Dwek, Eli; Slane, Patrick

    2012-01-01

    We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of approx 1.5 keV, or with two thermal components with temperatures of 1.5 and 0.2 keY. Previous studies suggest that the hot component may originate from reverse-shocked SN ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from supernova (SN) ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and IR emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of approx 140 K by a relatively dense, hot plasma, that also gives rise to the hot X-ray emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-ray emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) Solar Mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative

  18. Infrared and X-Ray Spectroscopy of the Kes 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties

    NASA Technical Reports Server (NTRS)

    Temim, Tea; Slane, Patrick; Arendt, Richard G.; Dwek, Eli

    2011-01-01

    We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of approximately 1.5 keY, or with two thermal components with temperatures of 1.5 and 0.2 keY. Previous studies suggest that the hot component may originate from reverse-shocked supernova (SN) ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from SN ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and IR emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of approximately 140 K by a relatively dense, hot plasma that also gives rise to the hot X-my emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-my emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) x solar mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide

  19. Infrared and X-Ray Spectroscopy of the KES 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties

    NASA Technical Reports Server (NTRS)

    Temim, Tea; Dwek, Eli; Slane, Patrick; Arendt, Richard G.

    2009-01-01

    We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of 1.5 keV, or with two thermal components with temperatures of 1.5 and 0.2 keV. Previous studies suggest that the hot component may originate from reverse-shocked SN ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from supernova (SN) ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and ill emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of 140 K by a relatively dense, hot plasma, that also gives rise to the hot X-ray emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-ray emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) solar mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative estimates of

  20. UV-assisted room temperature gas sensing of GaN-core/ZnO-shell nanowires

    NASA Astrophysics Data System (ADS)

    Park, Sunghoon; Ko, Hyunsung; Kim, Soohyun; Lee, Chongmu

    2014-11-01

    GaN is highly sensitive to low concentrations of H2 in ambient air and is almost insensitive to most other common gases. However, enhancing the sensing performance and the detection limit of GaN is a challenge. This study examined the H2-gas-sensing properties of GaN nanowires encapsulated with ZnO. GaN-core/ZnO-shell nanowires were fabricated by using a two-step process comprising the thermal evaporation of GaN powders and the atomic layer deposition of ZnO. The core-shell nanowires ranged from 80 to 120 nm in diameter and from a few tens to a few hundreds of micrometers in length, with a mean shell layer thickness of ~8 nm. Multiple-networked pristine GaN nanowire and ZnO-encapsulated GaN (or GaN-core/ZnO-shell) nanowire sensors showed responses of 120-147% and 179-389%, respectively, to 500-2,500 ppm of H2 at room temperature under UV (254 nm) illumination. The underlying mechanism of the enhanced response of the GaN nanowire to H2 gas when using ZnO encapsulation and UV irradiation is discussed.

  1. Novel shell device for gas exchange in an operculate land snail.

    PubMed

    Páll-Gergely, Barna; Naggs, Fred; Asami, Takahiro

    2016-07-01

    The operculum of terrestrial snails tightly seals the shell aperture providing protection from predators and body-water loss. To allow respiration with a closed operculum, operculate land snails repeatedly evolved shell devices such as tubes or channels that open to the air. In all Asian members of the Alycaeidae, an externally closed tube lies along the suture behind the aperture that possesses a small internal opening into the last whorl at the tube's anterior end. However, this structure presents a paradox: how is gas exchanged through an externally closed tube? Here we show that many microtunnels open into the tube and run beneath radial ribs along the growth line of the last whorl in Alycaeus conformis These tunnels open to the outside of the shell surface near the umbilicus. Examination under high magnification revealed that the outermost shell layer forms these tunnels only in the whorl range beneath the sutural tube. Each tunnel (ca 16 µm diameter) is far narrower than any known metazoan parasite. These findings support our hypothesis that the externally closed sutural tube functions with microtunnels as a specialized apparatus for predator-free gas exchange with minimal water loss when the operculum seals the aperture.

  2. Methods for Gas Sensing with Single-Walled Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B. (Inventor)

    2013-01-01

    Methods for gas sensing with single-walled carbon nanotubes are described. The methods comprise biasing at least one carbon nanotube and exposing to a gas environment to detect variation in temperature as an electrical response.

  3. Flammable gas double shell tank expert elicitation presentations (Part A and Part B)

    SciTech Connect

    Bratzel, D.R.

    1998-04-17

    This document is a compilation of presentation packages and white papers for the Flammable Gas Double Shell Tank Expert Elicitation Workshop {number_sign}2. For each presentation given by the different authors, a separate section was developed. The purpose for issuing these workshop presentation packages and white papers as a supporting document is to provide traceability and a Quality Assurance record for future reference to these packages.

  4. Gain of a single gas electron multiplier

    NASA Astrophysics Data System (ADS)

    Nemallapudi, Mythra Varun

    Gas Electron Multiplier (GEM) is a gaseous detector used in particle detection and is known for its high rate capability. Ever since its invention in 1997, GEM was applied in many areas and recently has been proposed to be installed in the CMS high η regions for upgrade at LHC, CERN. A complete understanding of the working and gain behaviour does not exist. GEM gain is influenced by charging up and this has been variedly interpreted in literature lacking consensus. I have attempted in this work through simulations and measurements to achieve a better understanding of single GEM gain and how it is affected by various factors. Specific experimental methods which evolved with subsequent measurements were employed to systematically study the charging up effect. Information from simulations was applied to characterize measurements thereby enabling the development of a model for charging up. Conductivity mechanism of the dielectric used in GEM was analyzed and the resistivity measured. Gain free of charging up effects was measured and this is appropriate for comparison with simulations.

  5. Evaluation of mitigation strategies in Facility Group 1 double-shell flammable-gas tanks at the Hanford Site

    SciTech Connect

    Unal, C.; Sadasivan, P.; Kubic, W.L.; White, J.R.

    1997-11-01

    Radioactive nuclear waste at the Hanford Site is stored in underground waste storage tanks at the site. The tanks fall into two main categories: single-shell tanks (SSTs) and double-shell tanks (DSTs). There are a total of 149 SSTs and 28 DSTs. The wastes stored in the tanks are chemically complex. They basically involve various sodium salts (mainly nitrite, nitrate, carbonates, aluminates, and hydroxides), organic compounds, heavy metals, and various radionuclides, including cesium, strontium, plutonium, and uranium. The waste is known to generate flammable gas (FG) [hydrogen, ammonia, nitrous oxide, hydrocarbons] by complex chemical reactions. The process of gas generation, retention, and release is transient. Some tanks reach a quasi-steady stage where gas generation is balanced by the release rate. Other tanks show continuous cycles of retention followed by episodic release. There currently are 25 tanks on the Flammable Gas Watch List (FGWL). The objective of this report is to evaluate possible mitigation strategies to eliminate the FG hazard. The evaluation is an engineering study of mitigation concepts for FG generation, retention, and release behavior in Tanks SY-101, AN-103, AN 104, An-105, and Aw-101. Where possible, limited quantification of the effects of mitigation strategies on the FG hazard also is considered. The results obtained from quantification efforts discussed in this report should be considered as best-estimate values. Results and conclusions of this work are intended to help in establishing methodologies in the contractor`s controls selection analysis to develop necessary safety controls for closing the FG unreviewed safety question. The general performance requirements of any mitigation scheme are discussed first.

  6. Examination of Simulated Non-Compliant Waste from Hanford Single-Shell Tanks

    SciTech Connect

    Wyrwas, Richard; Page, J. S.; Venetz, T. J.; Cooke, G. A.

    2014-07-10

    This report summarizes the electrochemical testing results for the aggressive layers testing recommended by the single-shell tank integrity expert panel. From single-shell chemistry data, 39 layers were identified as possible aggressive waste layers and were grouped by aggressive ion and inhibitor ions. From those groups 18 segments were identified as representative segments and tested. The testing reported here showed pitting corrosion for six aggressive layers, and one layer showed a propensity for crevice corrosion. In these cases there was a lack of inhibitors, an abundance of aggressive ions, or both. A good prediction for pitting corrosion could be made by considering the pH value of the layer. When the pH was less than 12, there was a high probability for pitting to occur. However, the pH of the solution was not always an indicator, and the inhibitor ion and aggressive ion concentrations then needed to be considered.

  7. Growth morphologies during cobalt-catalyzed single-shell carbon nanotube synthesis

    NASA Astrophysics Data System (ADS)

    Ajayan, P. M.; Lambert, J. M.; Bernier, P.; Barbedette, L.; Colliex, C.; Planeix, J. M.

    1993-12-01

    We report interesting growth morphologies produced during the electric arc-discharge between a graphite cathode and a composite cobalt—graphite anode, which includes the abundant formation of single-shell carbon nanotubes of 1-2 nm diameter. As the pressure inside the chamber and the cobalt content of the electrode are varied these "carbon monotubes" are formed in bundles and in high density under certain conditions in the soot, webs and string-like structures that decorate the chamber and also on a collaret that forms around the conventional deposit containing multi-shell nanotubes. We present high-resolution transmission electron microscopy images of these structures and propose conditions that promote single-tube growth. We also notice, in some cases, novel formation of regularly spaced cobalt particles enclosed in graphitic capsules and surrounded by sheaths of soot.

  8. Progress of the Enhanced Hanford Single Shell Tank (SST) Integrity Project

    SciTech Connect

    Venetz, Theodore J.; Washenfelder, Dennis J.; Boomer, Kayle D.; Johnson, Jeremy M.; Castleberry, Jim L.

    2015-01-07

    To improve the understanding of the single-shell tanks (SSTs) integrity, Washington River Protection Solutions, LLC (WRPS), the USDOE Hanford Site tank contractor, developed an enhanced Single-Shell Tank Integrity Project (SSTIP) in 2009. An expert panel on SST integrity, consisting of various subject matters experts in industry and academia, was created to provide recommendations supporting the development of the project. This panel developed 33 recommendations in four main areas of interest: structural integrity, liner degradation, leak integrity and prevention, and mitigation of contamination migration. In late 2010, seventeen of these recommendations were used to develop the basis for the M-45-10-1 Change Package for the Hanford Federal Agreement and Compliance Order, which is also known as the Tri-Party Agreement.

  9. Heat transfer characteristics of a single circular air jet impinging on a concave hemispherical shell

    NASA Technical Reports Server (NTRS)

    Livingood, J. N. B.; Gauntner, J. W.

    1973-01-01

    An experimental study was made of the local and average heat-transfer characteristics of a single turbulent air jet impinging on the concave surface of a hemisphere. Correlations were developed for expressing the effects of a number of dimensionless variables on the local and average Nusselt numbers. Results of the present study are compared with those from a similar study concerning a concave surface of a semicylindrical shell.

  10. Preliminary tank characterization report for single-shell tank 241-S-105: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-26

    An effort is underway to provide waste inventory estimates that will serve-as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-S-105 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  11. Evaluation of Hanford Single-Shell Waste Tanks Suspected of Water Intrusion

    SciTech Connect

    Feero, Amie J.; Washenfelder, Dennis J.; Johnson, Jeremy M.; Schofield, John S.

    2013-11-14

    Intrusions evaluations for twelve single-shell tanks were completed in 2013. The evaluations consisted of remote visual inspections, data analysis, and calculations of estimated intrusion rates. The observation of an intrusion or the preponderance of evidence confirmed that six of the twelve tanks evaluated had intrusions. These tanks were tanks 241-A-103, BX-101, BX-103, BX-110, BY-102, and SX-106.

  12. Summary of Group Development and Testing for Single Shell Tank Closure at Hanford

    SciTech Connect

    Harbour, John, R.

    2005-04-28

    This report is a summary of the bench-scale and large scale experimental studies performed by Savannah River National Laboratory for CH2M HILL to develop grout design mixes for possible use in producing fill materials as a part of Tank Closure of the Single-Shell Tanks at Hanford. The grout development data provided in this report demonstrates that these design mixes will produce fill materials that are ready for use in Hanford single shell tank closure. The purpose of this report is to assess the ability of the proposed grout specifications to meet the current requirements for successful single shell tank closure which will include the contracting of services for construction and operation of a grout batch plant. The research and field experience gained by SRNL in the closure of Tanks 17F and 20F at the Savannah River Site was leveraged into the grout development efforts for Hanford. It is concluded that the three Hanford grout design mixes provide fill materials that meet the current requirements for successful placement. This conclusion is based on the completion of recommended testing using Hanford area materials by the operators of the grout batch plant. This report summarizes the regulatory drivers and the requirements for grout mixes as tank fill material. It is these requirements for both fresh and cured grout properties that drove the development of the grout formulations for the stabilization, structural and capping layers.

  13. Ab initio Approach to Effective Single-Particle Energies in Doubly Closed Shell Nuclei

    SciTech Connect

    Duguet, T.

    2012-01-01

    The present work discusses, from an ab initio standpoint, the definition, the meaning, and the usefulness of effective single-particle energies (ESPEs) in doubly closed shell nuclei. We perform coupled-cluster calculations to quantify to what extent selected closed-shell nuclei in the oxygen and calcium isotopic chains can effectively be mapped onto an effective independent-particle picture. To do so, we revisit in detail the notion of ESPEs in the context of strongly correlated many-nucleon systems and illustrate the necessity of extracting ESPEs through the diagonalization of the centroid matrix, as originally argued by Baranger. For the purpose of illustration, we analyze the impact of correlations on observable one-nucleon separation energies and nonobservable ESPEs in selected closed-shell oxygen and calcium isotopes. We then state and illustrate the nonobservability of ESPEs. Similarly to spectroscopic factors, ESPEs can indeed be modified by a redefinition of inaccessible quantities while leaving actual observables unchanged. This leads to the absolute necessity of employing consistent structure and reaction models based on the same nuclear Hamiltonian to extract the shell structure in a meaningful fashion from experimental data.

  14. Demonstration of Confined Electron Gas and Steep-Slope Behavior in Delta-Doped GaAs-AlGaAs Core-Shell Nanowire Transistors.

    PubMed

    Morkötter, S; Jeon, N; Rudolph, D; Loitsch, B; Spirkoska, D; Hoffmann, E; Döblinger, M; Matich, S; Finley, J J; Lauhon, L J; Abstreiter, G; Koblmüller, G

    2015-05-13

    Strong surface and impurity scattering in III-V semiconductor-based nanowires (NW) degrade the performance of electronic devices, requiring refined concepts for controlling charge carrier conductivity. Here, we demonstrate remote Si delta (δ)-doping of radial GaAs-AlGaAs core-shell NWs that unambiguously exhibit a strongly confined electron gas with enhanced low-temperature field-effect mobilities up to 5 × 10(3) cm(2) V(-1) s(-1). The spatial separation between the high-mobility free electron gas at the NW core-shell interface and the Si dopants in the shell is directly verified by atom probe tomographic (APT) analysis, band-profile calculations, and transport characterization in advanced field-effect transistor (FET) geometries, demonstrating powerful control over the free electron gas density and conductivity. Multigated NW-FETs allow us to spatially resolve channel width- and crystal phase-dependent variations in electron gas density and mobility along single NW-FETs. Notably, dc output and transfer characteristics of these n-type depletion mode NW-FETs reveal excellent drain current saturation and record low subthreshold slopes of 70 mV/dec at on/off ratios >10(4)-10(5) at room temperature.

  15. Characterization of Direct Push Vadose Zone Sediments from the 241-U Single-Shell Tank Farm

    SciTech Connect

    Brown, Christopher F.; Valenta, Michelle M.; Serne, R. Jeffrey; Bjornstad, Bruce N.; Lanigan, David C.; Iovin, Cristian; Clayton, Ray E.; Geiszler, Keith N.; Clayton, Eric T.; Kutnyakov, Igor V.; Baum, Steven R.; Lindberg, Michael J.; Orr, Robert D.

    2007-12-20

    The overall goals of the Tank Farm Vadose Zone Project, led by CH2M HILL Hanford Group, Inc., are 1) to define risks from past and future single-shell tank farm activities, 2) to identify and evaluate the efficacy of interim measures, and 3) to aid, via collection of geochemical information and data, the future decisions that must be made by the U.S. Department of Energy (DOE) regarding the near-term operations, future waste retrieval, and final closure activities for the single-shell tank Waste Management Areas (WMAs). For a more complete discussion of the goals of the Tank Farm Vadose Zone Project, see the overall work plan, Phase 1 RCRA Facility Investigation/Corrective Measures Study Work Plan for the Single-Shell Tank Waste Management Areas (DOE 1999). Specific details on the rationale for activities performed at WMA U are found in Crumpler (2003). To meet these goals, CH2M HILL Hanford Group, Inc., asked scientists from Pacific Northwest National Laboratory (PNNL) to perform detailed analyses of vadose zone sediment collected within the U Single-Shell Tank Farm. Specifically, this report contains all the geochemical and selected physical characterization data collected on vadose zone sediment recovered from ten direct push characterization holes emplaced to investigate vadose zone contamination associated with potential leaks within the 241-U Single-Shell Tank Farm. Specific tanks targeted during this characterization campaign included tanks 241-U-104/241-U-105, 241-U-110, and 241-U-112. Additionally, this report compiles data from direct push samples collected north of tank 241-U-201, as well as sediment collected from the background borehole (C3393). After evaluating all the characterization and analytical data, there is no question that the vadose zone in the vicinity of tanks 241-U-104 and 241-U-105 has been contaminated by tank-related waste. This observation is not new, as gamma logging of drywells in the area has identified uranium contamination at the

  16. Development of the CD symcap platform to study gas-shell mix in implosions at the National Ignition Facility

    DOE PAGES

    Casey, D. T.; Smalyuk, V. A.; Tipton, R. E.; ...

    2014-09-09

    Surrogate implosions play an important role at the National Ignition Facility (NIF) for isolating aspects of the complex physical processes associated with fully integrated ignition experiments. The newly developed CD Symcap platform has been designed to study gas-shell mix in indirectly driven, pure T₂-gas filled CH-shell implosions equipped with 4 μm thick CD layers. This configuration provides a direct nuclear signature of mix as the DT yield (above a characterized D contamination background) is produced by D from the CD layer in the shell, mixing into the T-gas core. The CD layer can be placed at different locations within themore » CH shell to probe the depth and extent of mix. CD layers placed flush with the gas-shell interface and recessed up to 8 μm have shown that most of the mix occurs at the inner-shell surface. In addition, time-gated x-ray images of the hotspot show large brightly-radiating objects traversing through the hotspot around bang-time, which are likely chunks of CH/CD plastic. This platform is a powerful new capability at the NIF for understanding mix, one of the key performance issues for ignition experiments.« less

  17. Development of the CD symcap platform to study gas-shell mix in implosions at the National Ignition Facility

    SciTech Connect

    Casey, D. T.; Smalyuk, V. A.; Tipton, R. E.; Pino, J. E.; Grim, G. P.; Remington, B. A.; Rowley, D. P.; Weber, S. V.; Barrios, M.; Benedetti, L. R.; Bleuel, D. L.; Bond, E. J.; Bradley, D. K.; Caggiano, J. A.; Callahan, D. A.; Cerjan, C. J.; Chen, K. C.; Edgell, D. H.; Edwards, M. J.; Fittinghoff, D.; Frenje, J. A.; Gatu-Johnson, M.; Glebov, V. Y.; Glenn, S.; Guler, N.; Haan, S. W.; Hamza, A.; Hatarik, R.; Herrmann, H. W.; Hoover, D.; Hsing, W. W.; Izumi, N.; Kervin, P.; Khan, S.; Kilkenny, J. D.; Kline, J.; Knauer, J.; Kyrala, G.; Landen, O. L.; Ma, T.; MacPhee, A. G.; McNaney, J. M.; Mintz, M.; Moore, A.; Nikroo, A.; Pak, A.; Parham, T.; Petrasso, R.; Rinderknecht, H. G.; Sayre, D. B.; Schneider, M.; Stoeffl, W.; Tommasini, R.; Town, R. P.; Widmann, K.; Wilson, D. C.; Yeamans, C. B.

    2014-09-09

    Surrogate implosions play an important role at the National Ignition Facility (NIF) for isolating aspects of the complex physical processes associated with fully integrated ignition experiments. The newly developed CD Symcap platform has been designed to study gas-shell mix in indirectly driven, pure T₂-gas filled CH-shell implosions equipped with 4 μm thick CD layers. This configuration provides a direct nuclear signature of mix as the DT yield (above a characterized D contamination background) is produced by D from the CD layer in the shell, mixing into the T-gas core. The CD layer can be placed at different locations within the CH shell to probe the depth and extent of mix. CD layers placed flush with the gas-shell interface and recessed up to 8 μm have shown that most of the mix occurs at the inner-shell surface. In addition, time-gated x-ray images of the hotspot show large brightly-radiating objects traversing through the hotspot around bang-time, which are likely chunks of CH/CD plastic. This platform is a powerful new capability at the NIF for understanding mix, one of the key performance issues for ignition experiments.

  18. Off-shell single-top production at NLO matched to parton showers

    SciTech Connect

    Frederix, R.; Frixione, S.; Papanastasiou, A. S.; Prestel, S.; Torrielli, P.

    2016-06-06

    We study the hadroproduction of a Wb pair in association with a light jet, focusing on the dominant t-channel contribution and including exactly at the matrix-element level all non-resonant and off-shell effects induced by the finite top-quark width. Our simulations are accurate to the next-to-leading order in QCD, and are matched to the Herwig6 and Pythia8 parton showers through the MC@NLO method. We present phenomenological results relevant to the 8 TeV LHC, and carry out a thorough comparison to the case of on-shell t-channel single-top production. Furthermore, we formulate our approach so that it can be applied to the general case of matrix elements that feature coloured intermediate resonances and are matched to parton showers.

  19. Off-shell single-top production at NLO matched to parton showers

    DOE PAGES

    Frederix, R.; Frixione, S.; Papanastasiou, A. S.; ...

    2016-06-06

    We study the hadroproduction of a Wb pair in association with a light jet, focusing on the dominant t-channel contribution and including exactly at the matrix-element level all non-resonant and off-shell effects induced by the finite top-quark width. Our simulations are accurate to the next-to-leading order in QCD, and are matched to the Herwig6 and Pythia8 parton showers through the MC@NLO method. We present phenomenological results relevant to the 8 TeV LHC, and carry out a thorough comparison to the case of on-shell t-channel single-top production. Furthermore, we formulate our approach so that it can be applied to the generalmore » case of matrix elements that feature coloured intermediate resonances and are matched to parton showers.« less

  20. Mapping carrier diffusion in single silicon core-shell nanowires with ultrafast optical microscopy.

    PubMed

    Seo, M A; Yoo, J; Dayeh, S A; Picraux, S T; Taylor, A J; Prasankumar, R P

    2012-12-12

    Recent success in the fabrication of axial and radial core-shell heterostructures, composed of one or more layers with different properties, on semiconductor nanowires (NWs) has enabled greater control of NW-based device operation for various applications. (1-3) However, further progress toward significant performance enhancements in a given application is hindered by the limited knowledge of carrier dynamics in these structures. In particular, the strong influence of interfaces between different layers in NWs on transport makes it especially important to understand carrier dynamics in these quasi-one-dimensional systems. Here, we use ultrafast optical microscopy (4) to directly examine carrier relaxation and diffusion in single silicon core-only and Si/SiO(2) core-shell NWs with high temporal and spatial resolution in a noncontact manner. This enables us to reveal strong coherent phonon oscillations and experimentally map electron and hole diffusion currents in individual semiconductor NWs for the first time.

  1. Orion's Cloak - A rapidly expanding shell of gas centered on the Orion OB1 association

    NASA Technical Reports Server (NTRS)

    Cowie, L. L.; Songaila, A.; York, D. G.

    1979-01-01

    The structure of the interstellar gas surrounding the Orion OB1 association and the neighboring lambda Orionis association is detailed. UV absorption lime spectra of various ionization stages of C, N, Si and S in the directions of 12 stars were obtained by means of the spectrometer on board the Copernicus satellite. The presence of a shell of material surrounding the two associations and expanding at 100 to 120 km/sec, designated Orion's Cloak, was revealed, together with sporadically occurring higher column density matter at lower velocities. Results are interpreted to indicate the presence of a rapidly moving radiative shock outside the H II region of the association stars and inside this feature, a lower velocity, higher column density cloud which appears to be directly ionized by association stars. It is suggested that the gas features are caused by the effects of a recent supernova and of multiple supernovae, stellar winds and rocket-accelerated clouds in addition to stellar ionization.

  2. Characterization of core–shell MOF particles by depth profiling experiments using on-line single particle mass spectrometry

    DOE PAGES

    Cahill, J. F.; Fei, H.; Cohen, S. M.; ...

    2015-01-05

    Materials with core-shell structures have distinct properties that lend themselves to a variety of potential applications. Characterization of small particle core-shell materials presents a unique analytical challenge. Herein, single particles of solid-state materials with core-shell structures were measured using on-line aerosol time-of-flight mass spectrometry (ATOFMS). Laser 'depth profiling' experiments verified the core-shell nature of two known core-shell particle configurations (< 2 mu m diameter) that possessed inverted, complimentary core-shell compositions (ZrO2@SiO2 versus SiO2@ZrO2). The average peak area ratios of Si and Zr ions were calculated to definitively show their core-shell composition. These ratio curves acted as a calibrant for anmore » uncharacterized sample - a metal-organic framework (MOF) material surround by silica (UiO-66(Zr)@SiO2; UiO = University of Oslo). ATOFMS depth profiling was used to show that these particles did indeed exhibit a core-shell architecture. The results presented here show that ATOFMS can provide unique insights into core-shell solid-state materials with particle diameters between 0.2-3 mu m.« less

  3. Three-dimensional defocused orientation sensing of single bimetallic core-shell gold nanorods as multifunctional optical probes.

    PubMed

    Kim, Geun Wan; Lee, So Young; Ha, Ji Won

    2017-03-13

    Bimetallic core-shell gold nanorods (AuNRs) are promising multifunctional orientation probes that can be employed in biological and physical studies. This paper presents the optical properties of single AuNRs coated with palladium (Pd) and platinum (Pt) under scattering-based dark-field (DF) microscopy. Strong longitudinal plasmon damping was observed for the bimetallic AuNRs due to Pd and Pt metals on the AuNR surface. Despite the strong plasmon damping, the bimetallic AuNRs yielded characteristic doughnut-shaped scattering patterns under defocused DF microscopy. Interestingly, a solid bright spot appeared at the center of the defocused scattering patterns due to strong damping in the longitudinal plasmon and the increased contribution from the transverse dipoles to the image patterns, which was verified further by a simulation study. Furthermore, the defocused scattering field distributions enabled a determination of the three-dimensional (3D) orientations of single bimetallic AuNRs through a pattern-match analysis technique without angular degeneracy. Therefore, deeper insight into the optical properties and defocused scattering patterns of single bimetallic AuNRs is provided, which can be used to develop multifunctional optical probes that are capable of sensing of the 3D orientation of a probe, biomolecules based on LSPR shift, gas and humidity, etc.

  4. Gas sensors using single layer patterned interference optical filters

    NASA Astrophysics Data System (ADS)

    Rahmlow, Thomas D.; Gallagher, Kieran; Johnson, Robert L.

    2016-03-01

    A method for fabricating filters for fiber optic sensors is presented. The interference filter's construction is laid on it's side to allow for the use of air as the low refractive index material. Bandpass filters tuned to the absorption line of a trace gas can then be used as a sensitive means of detecting gas concentration. Complex filter designs can be fabricated in a single patterned layer. A CO2/CH4 gas sensor is presented as a design example.

  5. Theoretical investigation of single dopant in core/shell nanocrystal in magnetic field

    NASA Astrophysics Data System (ADS)

    Talbi, A.; Feddi, E.; Oukerroum, A.; Assaid, E.; Dujardin, F.; Addou, M.

    2015-09-01

    The control of single dopant or "solitary dopant" in semiconductors constitute a challenge to achieve new range of tunable optoelectronic devices. Knowing that the properties of doped monocrystals are very sensitive to different external perturbations, the aim of this study is to understand the effect of a magnetic field on the ground state energy of an off-center ionized donor in a core/shell quantum dot (CSQD). The binding energies with and without an applied magnetic field are determined by the Ritz variational method taking into account the electron-impurity correlation in the trial wave function deduced from the second-order perturbation. It has been found that the external magnetic field affects strongly the binding energy, and its effect varies as a function of the core radius and the shell thickness. We have shown the existence of a threshold ratio (a / b) crit which represents the limit between the tridimensional and the spherical surface confinement. In addition our analysis demonstrates the important influence of the position of ionized donor in the shell material.

  6. Shape, shell, and vacuole formation during the drying of a single concentrated whey protein droplet.

    PubMed

    Sadek, Céline; Tabuteau, Hervé; Schuck, Pierre; Fallourd, Yannick; Pradeau, Nicolas; Le Floch-Fouéré, Cécile; Jeantet, Romain

    2013-12-17

    The drying of milk concentrate droplets usually leads to specific particle morphology influencing their properties and their functionality. Understanding how the final shape of the particle is formed therefore represents a key issue for industrial applications. In this study, a new approach to the investigation of droplet-particle conversion is proposed. A single droplet of concentrated globular proteins extracted from milk was deposited onto a hydrophobic substrate and placed in a dry environment. Complementary methods (high-speed camera, confocal microscopy, and microbalance) were used to record the drying behavior of the concentrated protein droplets. Our results showed that whatever the initial concentration, particle formation included three dynamic stages clearly defined by the loss of mass and the evolution of the internal and external shapes of the droplet. A new and reproducible particle shape was related in this study. It was observed after drying a smooth, hemispherical cap-shaped particle, including a uniform protein shell and the nucleation of an internal vacuole. The particle morphology was strongly influenced by the drying environment, the contact angle, and the initial protein concentration, all of which governed the duration of the droplet shrinkage, the degree of buckling, and the shell thickness. These results are discussed in terms of specific protein behaviors in forming a predictable and a characteristic particle shape. The way the shell is formed may be the starting point in shaping particle distortion and thus represents a potential means of tuning the particle morphology.

  7. Tank characterization report for single-shell tank 241-C-109

    SciTech Connect

    DiCenso, A.T.; Amato, L.C.; Lambie, R.W.; Franklin, J.D.; Seymour, B.J.; Johnson, K.W.; Stevens, R.H.; Remund, K.M.; Sasaki, L.M.; Simpson, B.C.

    1995-02-01

    This document provides the characterization information and interprets the data for Single-Shell Tank 241-C-109. Single-Shell Tank 241-C-109 is an underground storage tank containing high-level radioactive waste. It is located in the C Tank Farm in the Hanford Site`s 200 East Area. The tank was sampled in September of 1992 to address the Ferrocyanide Unreviewed Safety Question. Analyses of tank waste were also performed to support Hanford Federal Facility Agreement and Consent Order Milestone M-44-08. Tank 241-C-109 went into service in 1946 and received first-cycle decontamination waste from bismuth phosphate process operations at B Plant in 1948. Other waste types added that are expected to contribute to the current contents include ferrocyanide scavenging waste and Strontium Semiworks waste. It is the last tank in a cascade with Tanks 241-C-107 and 241-C-108. The tank has a capacity of 2,010 kL (530 kgal) and currently contains 250 kL (66 kgal) of waste, existing primarily of sludge. Approximately 9.15 kL (4 kgal) of supernate remain. The sludge is heterogeneous, with significantly different chemical compositions depending on waste depth. The major waste constituents include aluminum, calcium, iron, nickel, nitrate, nitrite, phosphate, sodium, sulfate and uranium. The major radionuclides present are Cesium 137 and Strontium 90. The results of this characterization indicate that the waste in this tank is adequately described in the Dangerous Waste Permit Application of the Single-Shell Tank System.

  8. Detection of discretized single-shell penetration in mesoscopic vortex matter

    NASA Astrophysics Data System (ADS)

    Dolz, M. I.; Fasano, Y.; Cejas Bolecek, N. R.; Pastoriza, H.; Konczykowski, M.; van der Beek, C. J.

    2014-12-01

    We investigated configurational changes in mesoscopic vortex matter with less than thousand vortices during flux penetration in freestanding 50 μm diameter disks of Bi2Sr2CaCu2O8+δ. High-resolution AC and DC local magnetometry data reveal oscillations in the transmittivity echoed in peaks in the third-harmonics magnetic signal fainting on increasing vortex density. By means of extra experimental evidence and a simple geometrical analysis we show that these features fingerprint the discretized entrance of single-shells of vortices having a shape that mimics the sample edge.

  9. Tank selection for Light Duty Utility Arm (LDUA) system hot testing in a single shell tank

    SciTech Connect

    Bhatia, P.K.

    1995-01-31

    The purpose of this report is to recommend a single shell tank in which to hot test the Light Duty Utility Arm (LDUA) for the Tank Waste Remediation System (TWRS) in Fiscal Year 1996. The LDUA is designed to utilize a 12 inch riser. During hot testing, the LDUA will deploy two end effectors (a High Resolution Stereoscopic Video Camera System and a Still/Stereo Photography System mounted on the end of the arm`s tool interface plate). In addition, three other systems (an Overview Video System, an Overview Stereo Video System, and a Topographic Mapping System) will be independently deployed and tested through 4 inch risers.

  10. Characterization of the corrosion behavior of the carbon steel liner in Hanford Site single-shell tanks

    SciTech Connect

    Anantatmula, R.P.; Schwenk, E.B.; Danielson, M.J.

    1994-06-01

    Six safety initiatives have been identified for accelerating the resolution of waste tank safety issues and closure of unreviewed safety questions. Safety Initiative 5 is to reduce safety and environmental risk from tank leaks. Item d of Safety Initiative 5 is to complete corrosion studies of single-shell tanks to determine failure mechanisms and corrosion control options to minimize further degradation by June 1994. This report has been prepared to fulfill Safety Initiative 5, Item d. The corrosion mechanisms that apply to Hanford Site single-shell tanks are stress corrosion cracking, pitting/crevice corrosion, uniform corrosion, hydrogen embrittlement, and microbiologically influenced corrosion. The corrosion data relevant to the single-shell tanks dates back three decades, when results were obtained from in-situ corrosion coupons in a few single-shell tanks. Since that time there have been intertank transfers, evaporation, and chemical alterations of the waste. These activities have changed the character and the present composition of the waste is not well characterized. All conclusions and recommendations are made in the absence of relevant laboratory experimental data and tank inspection data. The report attempts to identify the failure mechanisms by a literature survey of carbon steel data in environments similar to the single-shell tank wastes, and by a review of the work performed at the Savannah River Site where similar wastes are stored in similar carbon steel tanks. Based on these surveys, and in the absence of data specific to Hanford single-shell tanks, it may be concluded that the single-shell tanks identified as leakers failed primarily by stress corrosion cracking due to the presence of high nitrate/low hydroxide wastes and residual stresses. In addition, some failures may be attributed to pitting under crevices in low hydroxide locations.

  11. Semi-analytical approach for the study of linear static behaviour and buckling of shells with single constant curvature

    NASA Astrophysics Data System (ADS)

    de Leo, Andrea Matteo; Contento, Alessandro; Di Egidio, Angelo

    2015-09-01

    A model of linear, internally constrained shell with single, constant curvature is used to describe the behaviour of existing structures, such as barrel shells. A linear, elastic, isotropic material is considered. Observing that in the shell two families of mono-dimensional interacting beams can be recognized: straight longitudinal beams and transversal arches, a non-conventional semi-analytical approximate solution, which uses the method of separation of variables, is proposed. By using an integral procedure, reduced differential, ordinary equations, capable of describing the behaviour of the shell, are obtained. Both linear static behaviour and longitudinal buckling of the shell are investigated. The approximate solution proposed leads to results that match those of a finite element model and permits to give a description of shells similar to that of beams on elastic soil. With regard to the linear static behaviour of the shell, a "short" and a "long" characterization is proposed and original graphical abaci are obtained with the purpose of facilitating the classification. An extensive study is then performed in order to analyse the buckling of the shells.

  12. Waste Characterization Plan for the Hanford Site single-shell tanks. Appendix D, Quality Assurance Project Plan for characterization of single-shell tanks: Revision 3

    SciTech Connect

    Hill, J.G.; Winters, W.I.; Simpson, B.C.; Buck, J.W.; Chamberlain, P.J.; Hunter, V.L.

    1991-09-01

    This section of the single-shell tank (SST) Waste Characterization Plan describes the quality control (QC) and quality assurance (QA) procedures and information used to support data that is collected in the characterization of SST wastes. The section addresses many of the same topics discussed in laboratory QA project plans (QAPjP) (WHC 1989, PNL 1989) and is responsive to the requirements of QA program plans (QAPP) (WHC 1990) associated with the characterization of the waste in the SSTs. The level of QC for the project depends on how the data is used. Data quality objectives (DQOs) are being developed to support decisions made using this data. It must be recognized that the decisions and information related to this part of the SST program deal with the materials contained within the tank only and not what may be in the environment/area surrounding the tanks. The information derived from this activity will be used to determine what risks may be incurred by the environment but are not used to define what actual constituents are contained within the soil surrounding the tanks. The phases defined within the DQOs on this Waste Characterization Plan follow the general guidance of the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) yet are pertinent to analysis of the contents of the tanks and not the environment.

  13. Contaminant Release Data Package for Residual Waste in Single-Shell Hanford Tanks

    SciTech Connect

    Deutsch, William J.; Cantrell, Kirk J.; Krupka, Kenneth M.

    2007-12-01

    The Hanford Federal Facility Agreement and Consent Order requires that a Resource Conservation and Recovery Act (RCRA) Facility Investigation report be submitted to the Washington State Department of Ecology. The RCRA Facility Investigation report will provide a detailed description of the state of knowledge needed for tank farm performance assessments. This data package provides detailed technical information about contaminant release from closed single-shell tanks necessary to support the RCRA Facility Investigation report. It was prepared by Pacific Northwest National Laboratory (PNNL) for CH2M HILL Hanford Group, Inc., which is tasked by the U.S. Department of Energy (DOE) with tank closure. This data package is a compilation of contaminant release rate data for residual waste in the four Hanford single-shell tanks (SSTs) that have been tested (C-103, C-106, C-202, and C-203). The report describes the geochemical properties of the primary contaminants of interest from the perspective of long-term risk to groundwater (uranium, technetium-99, iodine-129, chromium, transuranics, and nitrate), the occurrence of these contaminants in the residual waste, release mechanisms from the solid waste to water infiltrating the tanks in the future, and the laboratory tests conducted to measure release rates.

  14. Tank characterization report for single-shell tank 241-S-104

    SciTech Connect

    DiCenso, A.T.; Simpson, B.C.

    1994-09-29

    In July and August 1992, Single-Shell Tank 241-S-104 was sampled as part of the overall characterization effort directed by the Hanford Federal Facility Agreement and Consent Order. Sampling was also performed to determine proper handling of the waste, to address corrosivity and compatibility issues, and to comply with requirements of the Washington Administrative Code. This Tank Characterization Report presents an overview of that tank sampling and analysis effort, and contains observations regarding waste characteristics. It also presents expected concentration and bulk inventory data for the waste contents based on this latest sampling data and background historical and surveillance tank information. Finally, this report makes recommendations and conclusions regarding operational safety. The purpose of this report is to describe the characteristics the waste in Single-Shell Tank 241-S-104 (hereafter, Tank 241-S-104) based on information obtained from a variety of sources. This report summarizes the available information regarding the chemical and physical properties of the waste in Tank 241-S-104, and using the historical information to place the analytical data in context, arranges this information in a format useful for making management and technical decisions concerning waste tank safety and disposal issues. In addition, conclusions and recommendations are presented based on safety issues and further characterization needs.

  15. Limit Load and Buckling Analysis for Assessing Hanford Single-Shell Tank Dome Structural Integrity

    SciTech Connect

    Johnson, Kenneth I.; Deibler, John E.; Julyk, Larry J.; Karri, Naveen K.; Pilli, Siva Prasad

    2012-12-07

    The U.S. Department of Energy, Office of River Protection has commissioned a structural analysis of record (AOR) for the Hanford single shell tanks (SSTs) to assess their structural integrity. The analysis used finite element techniques to predict the tank response to the historical thermal and operating loads. The analysis also addressed the potential tank response to a postulated design basis earthquake. The combined response to static and seismic loads was then evaluated against the design requirements of American Concrete Institute (ACI) standard, ACI-349-06, for nuclear safety-related concrete structures. Further analysis was conducted to estimate the plastic limit load and the elastic-plastic buckling capacity of the tanks. The limit load and buckling analyses estimate the margin between the applied loads and the limiting load capacities of the tank structure. The potential for additional dome loads from waste retrieval equipment and the addition of large dome penetrations to accommodate retrieval equipment has generated additional interest in the limit load and buckling analyses. This paper summarizes the structural analysis methods that were used to evaluate the limit load and buckling of the single shell tanks.

  16. Effect of Doubly-excited States on Simulation of K- and L-shell Kr Gas Puff on ZR

    NASA Astrophysics Data System (ADS)

    Dasgupta, Arati; Thornhill, Ward; Giuliani, John; Ouart, Nick; Clark, Robert; Jones, Brent; Ampleford, Dave; Harvey-Thompson, Adam; Hansen, Stephanie; Coverdale, Christine

    2014-10-01

    A number of recent shots employing multi-shell gas puffs of Ar and Kr on the Sandia National Laboratories ZR accelerator have demonstrated unprecedented K-shell yields. The KAP TIXTL spectra of Ar gas puff shots with a Kr dopant in the middle shell show Kr L-shell lines near 2 keV. There have been also pure Kr shots on ZR. Krypton spectra from Z pinch implosions provide a wealth of information about the pinch dynamics and ionization history of the plasma. These spectra can be used together with experimental spectroscopic data to analyze the presence and dynamics of the emitting regions, which could dominate the Kr K- and L-shell yields. We will present synthetic K- and L-shell spectra with a detailed radiation transport scheme from the emission regions determined from Kr 1D simulations, employing a non-LTE collisional-radiative ionization kinetics model. We will also investigate the effects of state-specific dielectronic recombination on the populations and spectra of Z pinch Kr plasma. Work supported by DOE/NNSA. Sandia National laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation for the US Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  17. Single core-shell nanoparticle probes for non-invasive magnetic force microscopy.

    PubMed

    Uhlig, Tino; Wiedwald, Ulf; Seidenstücker, Axel; Ziemann, Paul; Eng, Lukas M

    2014-06-27

    We present an easy, fast and reliable method for the preparation of magnetic force microscopy (MFM) probes based on single Co nanoparticles (NPs). Due to their dipolar character, these magnetic probes open up a new approach for quantitative and non-invasive MFM measurements on the nanometer length scale. To guarantee long-term stability of these tips under ambient conditions, an ultrathin protecting Au shell was grown around the Co NPs through photochemical deposition. Single magnetic particles were firmly attached to standard silicon AFM tips using bifunctional self-assembling molecules. Such probes were tested on longitudinal magnetic recording media and compared to the results as recorded with conventional thin-film MFM tips. Easy data interpretation of the magnetic nanoparticle probes in a point dipole model is shown. Our nanoparticle tips provide excellent endurance for MFM recording, enable non-invasive probing while maintaining a high sensitivity, resolution, and reproducibility.

  18. On the Flutter of Cylindrical Shells and Panels Moving in a Flow of Gas

    NASA Technical Reports Server (NTRS)

    Stepanov, R. D.

    1958-01-01

    The equations of shells are taken in the form of the general technical theory of shallow shells and shells of medium length. The aerodynamic forces acting on a shell are taken into account only as forces of excess pressure according to the formula proposed by A.A. Iliushin in reference 3.

  19. Electronic shell structure and carrier dynamics of high aspect ratio InP single quantum dots

    NASA Astrophysics Data System (ADS)

    Beirne, Gareth J.; Reischle, Matthias; Roßbach, Robert; Schulz, Wolfgang-Michael; Jetter, Michael; Seebeck, Jan; Gartner, Paul; Gies, Christopher; Jahnke, Frank; Michler, Peter

    2007-05-01

    Systematic excitation-power-density dependent and time-resolved single-dot photoluminescence studies have been performed on type-I InP/Ga0.51In0.49P quantum dots. These dots are rather flat and therefore exhibit larger than normal single-dot ground-state transition energies ranging from 1.791 to 1.873eV . As a result of their low height, the dots have a very high aspect ratio (ratio of width to height) of approximately 27:1 . In general, even at high excitation power densities, the dots with ground-state transition energies above 1.82eV exhibit only s -shell emission, while the larger dots exhibiting ground-state emission below 1.82eV tend to exhibit emission from several (in some cases up to eight) shells. Calculations indicate that this change is due to the smaller dots having only one confined election level while the larger dots have two or more. Time-resolved investigations indicate the presence of fast carrier relaxation and recombination processes for both dot types, however, only the larger dots display clear interlevel relaxation effects as expected. The temporal behavior has been qualitatively simulated using a rate equation model. Also, in a more detailed analysis, the fast carrier relaxation is described on the basis of a quantum kinetic treatment of the carrier-phonon interaction. Finally, the dots display a clear single-photon emission signature in photon statistics measurements.

  20. Core/shell structured magnetic nanoparticles synthesized by inert gas condensation

    NASA Astrophysics Data System (ADS)

    Ceylan, Abdullah

    In this work, it is our goal to investigate the structural and magnetic properties of core/shell magnetic nanoparticles synthesized by inert gas condensation technique. For that purpose, Fe/FeO, Fe/FeO/PMMA, Ni/NiO/CoO, and NiFe 2O4 have been chosen to study exchange bias phenomenon that is observed in these systems. Two sets (small and large) of Fe/FeO nanoparticles with different particle sizes, (6.0/1.5nm and 9.0/3.0nm) have been prepared and the magnetic properties in terms of temperature dependencies of exchange bias field (H EB, horizontal shift of the hysteresis loops) and magnetic viscosity were investigated. Small particles have shown superparamagnetic behavior above Blocking Temperature, TB and exhibited 1574+/-25Oe exchange bias whereas the large particles had 277+/-25Oe. It has been observed that HEB is inversely proportional with the particle size and exponentially decreases and vanishes as the temperature increases up to TB. Along with the horizontal shift, vertical shift of the hysteresis loops due to pinned interface spins has also been realized. Dispersion of 14nm Fe/FeO particles in a non-magnetic polymer PMMA in order to study interparticle interactions has revealed that the magnetic response is in general nonmonotonic as a function of particle concentration in the polymer. The nonmonotonic behavior is linked to the competition between the exchange and dipolar interactions one of which being dominant above/below a threshold concentration. In order to synthesize core/shell nanoparticles composed of different metal and metal oxides rather than metal and its native oxide forming the core/shell, two techniques, resistive evaporation and laser ablation, have been combined in our inert gas condensation system. Condensation of evaporated Ni and laser ablated CoO allowed us to prepare core/shell particles. Structural analyses have revealed that Ni/CoO nanoparticles with a thin (˜1nm) NiO intermediate layer in the form of Ni/NiO/CoO can only be formed

  1. Functions and requirements for subsurface barriers used in support of single-shell tank waste retrieval

    SciTech Connect

    Lowe, S.S.

    1993-11-16

    The mission of the Tank Waste Remediation System (TWRS) Program is to store, treat, and immobilize highly radioactive Hanford waste in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Program includes project and program activities for receiving, storing, maintaining, treating, and disposing onsite, or packaging for offsite disposal, all Hanford tank waste. Hanford tank waste includes the contents of 149 single-shell tanks (SSTs) and 28 double-shell tanks (DSTs), plus any new waste added to these facilities, and all encapsulated cesium and strontium stored onsite and returned from offsite users. A key element of the TWRS Program is retrieval of the waste in the SSTs. The waste stored in these underground tanks must be removed in order to minimize environmental, safety, and health risks associated with continuing waste storage. Subsurface barriers are being considered as a means to mitigate the effects of tank leaks including those occurring during SST waste retrieval. The functions to be performed by subsurface barriers based on their role in retrieving waste from the SSTs are described, and the requirements which constrain their application are identified. These functions and requirements together define the functional baseline for subsurface barriers.

  2. A nonlocal shell model for mode transformation in single-walled carbon nanotubes.

    PubMed

    Shi, M X; Li, Q M; Huang, Y

    2009-11-11

    A second-order strain gradient nonlocal shell model is established to study the mode transformation in single-walled carbon nanotubes (SWCNTs). Nonlocal length is calibrated carefully for SWCNTs in reference to molecular dynamics (MD) simulations through analysis of nonlocal length effects on the frequencies of the radial breathing mode (RBM) and circumferential flexural modes (CFMs) and its effects on mode transformation. All analyses show that only a negative second-order nonlocal shell model is appropriate to SWCNTs. Nonlocal length is evidently related to vibration modes and the radius-to-thickness ratio. It is found that a nonlocal length is approximately 0.1 nm in an average sense when RBM frequency is concerned. A nonlocal length of 0.122-0.259 nm is indicated for the mode transformation in a selected group of armchair SWCNTs. 2:1 and 1:1 internal resonances are found for the same SWCNT based on different models, which implies that the internal resonance mechanism depends on the model employed. Furthermore, it is shown that an effective thickness of approximately 0.1 nm is more appropriate to SWCNTs than 0.066 nm.

  3. Effect of Swirl on an Unstable Single-Element Gas-gas Rocket Engine (Briefing Charts)

    DTIC Science & Technology

    2014-07-01

    Single-Element Gas-gas Rocket Engine 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Matt Harvazinski, Venke...the Apollo program > 2000 full scale tests > $400 million for propellants alone (2010 prices) 4 Approved for public release; distribution unlimited

  4. Trade study of leakage detection, monitoring, and mitigation technologies to support Hanford single-shell waste retrieval

    SciTech Connect

    Hertzel, J.S.

    1996-03-01

    The U.S. Department of Energy has established the Tank Waste Remediation System to safely manage and dispose of low-level, high-level, and transuranic wastes currently stored in underground storage tanks at the Hanford Site in Eastern Washington. This report supports the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone No. M-45-08-T01 and addresses additional issues regarding single-shell tank leakage detection, monitoring, and mitigation technologies and provide an indication of the scope of leakage detection, monitoring, and mitigation activities necessary to support the Tank Waste Remedial System Initial Single-shell Tank Retrieval System project.

  5. Characterization of preservative and pesticide as potential of bio oil compound from pyrolisis of cocoa shell using gas chromatography

    NASA Astrophysics Data System (ADS)

    Mashuni, Jahiding, M.; Kurniasih, I.; Zulkaidah

    2017-03-01

    Cocoa shell is one of the plant waste that has not been widely used. Cocoa shell is potential as a producer of bio oil because it contains lignocellulose. The bio oil of Liquid volatile matter (LVM) is the products of smoke condensation from the pyrolysis reactor. The bio oil of cocoa shell from pyrolysis process can be made as raw materials for the application of pesticide and preservative. The aims of this research were to produce bio oil from cocoa shell by pyrolysis and analyzing the content using Gas Chromatography (GC). Bio oil production was done by pyrolysis with variations of temperature, i.e. 400, 500, 600 and 700 °C. Pyrolysis reaction generates three products: gas, liquid and solid. The yield of bio oil with variations of pyrolisis temperature, i.e. 400, 500, 600 and 700 °C were obtained i.e. 46, 45, 44 and 40% (v/w), respectively. The chromatogram results showed the chemical components of bio oil from the cocoa shell were ammonia, hexane, alcohol, ketone, acid and phenolic compounds which can be used as material of preservative and pesticide.

  6. Seniority in quantum many-body systems. I. Identical particles in a single shell

    SciTech Connect

    Van Isacker, P.

    2014-10-15

    A discussion of the seniority quantum number in many-body systems is presented. The analysis is carried out for bosons and fermions simultaneously but is restricted to identical particles occupying a single shell. The emphasis of the paper is on the possibility of partial conservation of seniority which turns out to be a peculiar property of spin-9/2 fermions but prevalent in systems of interacting bosons of any spin. Partial conservation of seniority is at the basis of the existence of seniority isomers, frequently observed in semi-magic nuclei, and also gives rise to peculiar selection rules in one-nucleon transfer reactions. - Highlights: • Unified derivation of conditions for the total and partial conservation of seniority. • General analysis of the partial conservation of seniority in boson systems. • Why partial conservation of seniority is crucial for seniority isomers in nuclei. • The effect of partial conservation of seniority on one-nucleon transfer intensities.

  7. Investigation into Photoconductivity in Single CNF/TiO2-Dye Core-Shell Nanowire Devices

    NASA Astrophysics Data System (ADS)

    Li, Zhuangzhi; Rochford, Caitlin; Javier Baca, F.; Liu, Jianwei; Li, Jun; Wu, Judy

    2010-09-01

    A vertically aligned carbon nanofiber array coated with anatase TiO2 (CNF/TiO2) is an attractive possible replacement for the sintered TiO2 nanoparticle network in the original dye-sensitized solar cell (DSSC) design due to the potential for improved charge transport and reduced charge recombination. Although the reported efficiency of 1.1% in these modified DSSC’s is encouraging, the limiting factors must be identified before a higher efficiency can be obtained. This work employs a single nanowire approach to investigate the charge transport in individual CNF/TiO2 core-shell nanowires with adsorbed N719 dye molecules in dark and under illumination. The results shed light on the role of charge traps and dye adsorption on the (photo) conductivity of nanocrystalline TiO2 CNF’s as related to dye-sensitized solar cell performance.

  8. Preliminary tank characterization report for single-shell tank 241-TX-111: Best-basis inventory

    SciTech Connect

    Place, D.E.

    1997-08-26

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-111 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task. The best-basis inventory is based on an engineering assessment of waste type, process flowsheet data, early sample data, and/or other available information. The Standard Inventories of Chemicals and Radionuclides in Hanford Site Tank Wastes (Kupfer et al. 1997) describes standard methodology used to derive the tank-by-tank best-basis inventories. This preliminary TCR will be updated using this same methodology when additional data on tank contents become available.

  9. Preliminary tank characterization report for single-shell tank 241-TX-101: best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-09-02

    This document is a preliminary Tank Characterization Report (TCR). It only contains the current best-basis inventory (Appendix D) for single-shell tank 241-TX-101. No TCRs have been previously issued for this tank, and current core sample analyses are not available. The best-basis inventory, therefore, is based on an engineering assessment of waste type, process flowsheet data, early sample data, and/or other available information. The Standard Inventories of Chemicals and Radionuclides in Hanford Site Tank Wastes describes standard methodology used to derive the tank-by-tank best-basis inventories. This preliminary TCR will be updated using this same methodology when additional data on tank contents become available.

  10. Preliminary tank characterization report for single-shell tank 241-TX-106: Best-basis inventory

    SciTech Connect

    Kupfer, M.J.

    1997-08-26

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-106 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task. The best-basis inventory is based on an engineering assessment of waste type, process flowsheet data, early sample data, and/or other available information. The Standard Inventories of Chemicals and Radionuclides in Hanford Site Tank Wastes (Kupfer et al. 1997) describes standard methodology used to derive the tank-by-tank best-basis inventories. This preliminary TCR will be updated using this same methodology when additional data on tank contents become available.

  11. Preliminary tank characterization report for single-shell tank 241-TX-112: Best-basis inventory

    SciTech Connect

    Place, D.E.

    1997-08-26

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the various waste management activities. As part of this effort, an evaluation of available information for single-shell tank 241-TX-112 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task. The best-basis inventory is based on an engineering assessment of waste type, process flowsheet data, early sample data, and other available information. The Standard Inventories of Chemicals and Radionuclides in Hanford Site Tank Wastes (Kupfer et al. 1997) describes standard methodology used to derive the tank-by-tank best-basis inventories. This preliminary TCR will be updated using this same methodology when additional data on tank contents become available.

  12. Preliminary tank characterization report for single-shell tank 241-TX-113: best-basis inventory

    SciTech Connect

    Place, D.E.

    1997-08-26

    This document is a preliminary Tank Characterization Report (TCR). It only contains the current best-basis inventory (Appendix D) for single-shell tank 241-TX-113. No TCRs have been previously issued for this tank, and current core sample analyses are not available. The best-basis inventory, therefore, is based on an engineering assessment of waste type, process flowsheet data, early sample data, and/or other available information. The Standard Inventories of Chemicals and Radionuclides in Hanford Site Tank Wastes describes standard methodology used to derive the tank-by-tank best-basis inventories. This preliminary TCR will be updated using this same methodology when additional data on tank contents become available.

  13. Preliminary tank characterization report for single-shell tank 241-TX-108: best-basis inventory

    SciTech Connect

    Jo, J.

    1997-08-26

    This document is a preliminary Tank Characterization Report (TCR). It only contains the current best-basis inventory (Appendix D) for single-shell tank 241-TX-108. No TCR has been previously issued for this tank, and current core sample analyses are not available. The best-basis inventory, therefore, is based on an engineering assessment of waste type, process flowsheet data, and/or other available information. The Standard Inventories of Chemicals and Radionuclides in Hanford Site Tank Wastes describes standard methodology used to derive the tank-by-tank best-basis inventories. This preliminary TCR will be updated using this same methodology when additional data on tank contents become available.

  14. OVERVIEW OF ENHANCED HANFORD SINGLE-SHELL TANK (SST) INTEGRITY PROJECT - 12128

    SciTech Connect

    VENETZ TJ; BOOMER KD; WASHENFELDER DJ; JOHNSON JB

    2012-01-25

    To improve the understanding of the single-shell tanks integrity, Washington River Protection Solutions, LLC, the USDOE Hanford Site tank contractor, developed an enhanced Single-Shell Tank (SST) Integrity Project in 2009. An expert panel on SST integrity, consisting of various subject matters experts in industry and academia, was created to provide recommendations supporting the development of the project. This panel developed 33 recommendations in four main areas of interest: structural integrity, liner degradation, leak integrity and prevention, and mitigation of contamination migration, Seventeen of these recommendations were used to develop the basis for the M-45-10-1 Change Package for the Hanford Federal Agreement and Compliance Order, which is also known as the Tri-Party Agreement. The change package identified two phases of work for SST integrity. The initial phase has been focused on efforts to envelope the integrity of the tanks. The initial phase was divided into two primary areas of investigation: structural integrity and leak integrity. If necessary based on the outcome from the initial work, a second phase would be focused on further definition of the integrity of the concrete and liners. Combined these two phases are designed to support the formal integrity assessment of the Hanford SSTs in 2018 by Independent Qualified Registered Engineer. The work to further define the DOE's understanding of the structural integrity SSTs involves preparing a modern Analysis of Record using a finite element analysis program. Structural analyses of the SSTs have been conducted since 1957, but these analyses used analog calculation, less rigorous models, or focused on individual structures. As such, an integrated understanding of all of the SSTs has not been developed to modern expectations. In support of this effort, other milestones will address the visual inspection of the tank concrete and the collection of concrete core samples from the tanks for analysis of

  15. Tank characterization report for single-shell tank 241-C-109

    SciTech Connect

    Simpson, B.C.

    1997-05-23

    One of the major functions of the Tank Waste Remediation System (TWRS) is to characterize wastes in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis, along with other available information about a tank, are compiled and maintained in a tank characterization report (TCR). This report and its appendices serve as the TCR for single-shell tank 241-C-109. The objectives of this report are: (1) to use characterization data in response to technical issues associated with tank 241 C-109 waste; and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. The response to technical issues is summarized in Section 2.0, and the best-basis inventory estimate is presented in Section 3.0. Recommendations regarding safety status and additional sampling needs are provided in Section 4.0. Supporting data and information are contained in the appendices.

  16. Tank characterization report for single-shell tank 241-B-104

    SciTech Connect

    Field, J.G.

    1996-04-08

    This document summarizes information on the historical uses, present status, and the sampling and analysis results of waste stored in Tank 241-B-104. Sampling and analyses meet safety screening and historical data quality objectives. This report supports the requirements of Tri-party Agreement Milestone M-44-09. his characterization report summoned the available information on the historical uses and the current status of single-shell tank 241-B-104, and presents the analytical results of the June 1995 sampling and analysis effort. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order Milestone M-44-09 (Ecology et al. 1994). Tank 241-B-104 is a single-shell underground waste storage tank located in the 200 East Area B Tank Farm on the Hanford Site. It is the first tank in a three-tank cascade series. The tank went into service in August 1946 with a transfer of second-cycle decontamination waste generated from the bismuth phosphate process. The tank continued to receive this waste type until the third quarter of 1950, when it began receiving first-cycle decontamination waste also produced during the bismuth phosphate process. Following this, the tank received evaporator bottoms sludge from the 242-B Evaporator and waste generated from the flushing of transfer lines. A description and the status of tank 241-B-104 are sum in Table ES-1 and Figure ES-1. The tank has an operating capacity of 2,010 kL (530 kgal), and presently contains 1,400 kL (371 kgal) of waste. The total amount is composed of 4 kL (1 kgal) of supernatant, 260 kL (69 kgal) of saltcake, and 1,140 kL (301 kgal) of sludge (Hanlon 1995). Current surveillance data and observations appear to support these results.

  17. Groundwater Quality Assessment Plan for Single-Shell Tank Waste Management Area U

    SciTech Connect

    Smith, Ronald M.; Hodges, Floyd N.; Williams, Barbara A.

    2001-08-29

    Single-Shell Tank Waste Management Area U (WMA U) is in the 200 West Area on the Hanford Site. The area includes the U Tank Farm that contains 16 underground, single-shell tanks and their ancillary equipment and waste systems. WMA U is regulated under the Resource Conservation and Recovery Act of 1976 (RCRA) as codified in 40 CFR Part 265, Subpart F and Washington's Hazardous Waste Management Act (HWMA, RCW 70.105) and its implementing requirements in the Washington State dangerous waste regulations (WAC 173-303-400). Releases of hazardous wastes from WMA U have contaminated groundwater beneath the area. Therefore, the WMA U is being assessed to determine the rate of movement and extent of the contamination released and to determine the concentrations in groundwater. The original finding of groundwater impact was determined from elevated specific conductance in downgradient well 299-W19-41. The elevated specific conductance was attributed to the nonhazardous constituents calcium, magnesium, sulfate, and chloride. Tank waste constituents nitrate and technetium-99 are also present as co-contaminants and have increased over the past several years; however, at concentrations well below the respective drinking water standards. Chromium concentrations in downgradient wells have generally exceeded background levels, but similar levels were also observed in upgradient well 299-W18-25 in early 2000 before it went dry. The objective of this report is to present the current conceptual model for how and where contaminant releases have reached the water table and how that contamination has dispersed in the groundwater system. These efforts will achieve the requirements of a groundwater quality assessment under RCRA [40 CFR 265.93 (d)(4)]. On that basis, a monitoring schedule with appropriate analytes and proposals for new wells and tests are presented in this document.

  18. Single-ring magnetic cusp low gas pressure ion source

    DOEpatents

    Bacon, Frank M.; Brainard, John P.; O'Hagan, James B.; Walko, Robert J.

    1985-01-01

    A single-ring magnetic cusp low gas pressure ion source designed for use in a sealed, nonpumped neutron generator utilizes a cathode and an anode, three electrically floating electrodes (a reflector behind the cathode, a heat shield around the anode, and an aperture plate), together with a single ring-cusp magnetic field, to establish and energy-filtering mechanism for producing atomic-hydrogen ions.

  19. Neutron production in deuterium gas-puff z-pinch with outer plasma shell at current of 3 MA

    NASA Astrophysics Data System (ADS)

    Cikhardt, J.; Klir, D.; Rezac, K.; Cikhardtova, B.; Kravarik, J.; Kubes, P.; Sila, O.; Shishlov, A. V.; Cherdizov, R. K.; Frusov, F. I.; Kokshenev, V. A.; Kurmaev, N. E.; Labetsky, A. Yu.; Ratakhin, N. A.; Dudkin, G. N.; Garapatsky, A. A.; Padalko, V. N.; Varlachev, V. A.; Turek, K.; Krasa, J.

    2015-11-01

    Z-pinch experiments at the current of about 3 MA were carried out on the GIT-12 generator. The outer plasma shell of deuterium gas-puff was generated by the system of 48 plasma guns. This configuration exhibits a high efficiency of the production of DD fusion neutrons with the yield of above 1012 neutrons produced in a single shot with the duration of about 20 ns. The maximum energy of the neutrons produced in this pulse exceeded 30 MeV. The neutron radiation was measured using scintillation TOF detectors, CR-39 nuclear track detectors, bubble detectors BD-PND and BDS-10000 and by several types of nuclear activation detectors. These diagnostic tools were used to measure the anisotropy of neutron fluence and neutron energy spectra. It allows us to estimate the total number of DD neutrons, the contribution of other nuclear reactions, the amount of scattered neutrons, and other parameters of neutron production. This work was supported by the MSMT grants LH13283, LD14089.

  20. A Single Nanobelt Transistor for Gas Identification: Using a Gas-Dielectric Strategy.

    PubMed

    Cai, Bin; Song, Zhiqi; Tong, Yanhong; Tang, Qingxin; Shaymurat, Talgar; Liu, Yichun

    2016-06-21

    Despite tremendous potential and urgent demand in high-response low-cost gas identification, the development of gas identification based on a metal oxide semiconductor nanowire/nanobelt remains limited by fabrication complexity and redundant signals. Researchers have shown a multisensor-array strategy with "one key to one lock" configuration. Here, we describe a new strategy to create high-response room-temperature gas identification by employing gas as dielectric. This enables gas discrimination down to the part per billion (ppb) level only based on one pristine single nanobelt transistor, with the excellent average Mahalanobis distance (MD) as high as 35 at the linear discriminant analysis (LDA) space. The single device realizes the selective recognition function of electronic nose. The effect of the gas dielectric on the response of the multiple field-effect parameters is discussed by the comparative investigation of gas and solid-dielectric devices and the studies on trap density changes in the conductive channel. The current work opens up exciting opportunities for room-temperature gas recognition based on the pristine single device.

  1. A Single Nanobelt Transistor for Gas Identification: Using a Gas-Dielectric Strategy

    PubMed Central

    Cai, Bin; Song, Zhiqi; Tong, Yanhong; Tang, Qingxin; Shaymurat, Talgar; Liu, Yichun

    2016-01-01

    Despite tremendous potential and urgent demand in high-response low-cost gas identification, the development of gas identification based on a metal oxide semiconductor nanowire/nanobelt remains limited by fabrication complexity and redundant signals. Researchers have shown a multisensor-array strategy with “one key to one lock” configuration. Here, we describe a new strategy to create high-response room-temperature gas identification by employing gas as dielectric. This enables gas discrimination down to the part per billion (ppb) level only based on one pristine single nanobelt transistor, with the excellent average Mahalanobis distance (MD) as high as 35 at the linear discriminant analysis (LDA) space. The single device realizes the selective recognition function of electronic nose. The effect of the gas dielectric on the response of the multiple field-effect parameters is discussed by the comparative investigation of gas and solid-dielectric devices and the studies on trap density changes in the conductive channel. The current work opens up exciting opportunities for room-temperature gas recognition based on the pristine single device. PMID:27338394

  2. Using Single Drop Microextraction for Headspace Analysis with Gas Chromatography

    ERIC Educational Resources Information Center

    Riccio, Daniel; Wood, Derrick C.; Miller, James M.

    2008-01-01

    Headspace (HS) gas chromatography (GC) is commonly used to analyze samples that contain non-volatiles. In 1996, a new sampling technique called single drop microextraction, SDME, was introduced, and in 2001 it was applied to HS analysis. It is a simple technique that uses equipment normally found in the undergraduate laboratory, making it ideal…

  3. Phase 1 RCRA Facility Investigation and Corrective Measures Study Work Plan for Single Shell Tank Waste Management Areas

    SciTech Connect

    ROGERS, P.M.

    2000-06-01

    This document is the master work plan for the Resource Conservation and Recovery Act of 1976 (RCRA) for single-shell tank (SST) farms at the Hanford Site. Evidence indicates that releases at four of the seven SST waste management areas have impacted.

  4. Enhancement of single particle rare earth doped NaYF4: Yb, Er emission with a gold shell

    NASA Astrophysics Data System (ADS)

    Li, Ling; Green, Kory; Hallen, Hans; Lim, Shuang Fang

    2015-01-01

    Upconversion of infrared light to visible light has important implications for bioimaging. However, the small absorption cross-section of rare earth dopants has limited the efficiency of these anti-Stokes nanomaterials. We present enhanced excitation absorption and single particle fluorescent emission of sodium yttrium fluoride, NaYF4: Yb, Er based upconverting nanoparticles coated with a gold nanoshell through surface plasmon resonance. The single gold-shell coated nanoparticles show enhanced absorption in the near infrared, enhanced total emission intensity, and increased green relative to red emission. We also show differences in enhancement between single and aggregated gold shell nanoparticles. The surface plasmon resonance of the gold-shell coated nanoparticle is shown to be dependent on the shell thickness. In contrast to other reported results, our single particle experimental observations are corroborated by finite element calculations that show where the green/red emission enhancement occurs, and what portion of the enhancement is due to electromagnetic effects. We find that the excitation enhancement and green/red emission ratio enhancement occurs at the corners and edges of the doped emissive core.

  5. INITIAL SINGLE SHELL TANK (SST) SYSTEM PERFORMANCE ASSESSMENT OF THE HANFORD SITE

    SciTech Connect

    JARAYSI, M.N.

    2007-01-08

    The ''Initial Single-Shell Tank System Performance Assessment for the Hanford Site [1] (SST PA) presents the analysis of the long-term impacts of residual wastes assumed to remain after retrieval of tank waste and closure of the SST farms at the US Department of Energy (DOE) Hanford Site. The SST PA supports key elements of the closure process agreed upon in 2004 by DOE, the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA). The SST PA element is defined in Appendix I of the ''Hanford Federal Facility Agreement and Consent Order'' (HFFACO) (Ecology et al. 1989) [2], the document that establishes the overall closure process for the SST and double-shell tank (DST) systems. The approach incorporated in the SST PA integrates substantive features of both hazardous and radioactive waste management regulations into a single analysis. The defense-in-depth approach used in this analysis defined two major engineering barriers (a surface barrier and the grouted tank structure) and one natural barrier (the vadose zone) that will be relied on to control waste release into the accessible environment and attain expected performance metrics. The analysis evaluates specific barrier characteristics and other site features that influence contaminant migration by the various pathways. A ''reference'' case and a suite of sensitivity/uncertainty cases are considered. The ''reference case'' evaluates environmental impacts assuming central tendency estimates of site conditions. ''Reference'' case analysis results show residual tank waste impacts on nearby groundwater, air resources; or inadvertent intruders to be well below most important performance objectives. Conversely, past releases to the soil, from previous tank farm operations, are shown to have groundwater impacts that re significantly above most performance objectives. Sensitivity/uncertainty cases examine single and multiple parameter variability along with plausible alternatives

  6. Tank characterization report for single-shell tank 241-T-104

    SciTech Connect

    DiCenso, A.T.; Simpson, B.C.

    1994-09-29

    In August 1992, Single-Shell Tank 241-T-104 was sampled to determine proper handling of the waste, to address corrosivity and compatibility issues, and to comply with requirements of the Washington Administrative Code (Ecology, 1991). This Tank Characterization Report presents an overview of that tank sampling and analysis effort, and contains observations regarding waste characteristics. It also addresses expected concentration and bulk inventory data for the waste contents based on this latest sampling data and background tank information. The purpose of this report is to describe and characterize the waste in Single-Shall Tank 241-T-104 (hereafter, Tank 241-T-104) based on information given from various sources. This report summarizes the available information regarding the waste in Tank 241-T-104, and using the historical information to place the analytical data in context, arranges this information in a useful format for making management and technical decisions concerning this waste tank. In addition, conclusions and recommendations are given based on safety issues and further characterization needs.

  7. Engineering high-performance Pd core-MgO porous shell nanocatalysts via heterogeneous gas-phase synthesis

    NASA Astrophysics Data System (ADS)

    Singh, Vidyadhar; Cassidy, Cathal; Abild-Pedersen, Frank; Kim, Jeong-Hwan; Aranishi, Kengo; Kumar, Sushant; Lal, Chhagan; Gspan, Christian; Grogger, Werner; Sowwan, Mukhles

    2015-08-01

    We report on the design and synthesis of high performance catalytic nanoparticles with a robust geometry via magnetron-sputter inert-gas condensation. Sputtering of Pd and Mg from two independent neighbouring targets enabled heterogeneous condensation and growth of nanoparticles with controlled Pd core-MgO porous shell structure. The thickness of the shell and the number of cores within each nanoparticle could be tailored by adjusting the respective sputtering powers. The nanoparticles were directly deposited on glassy carbon electrodes, and their catalytic activity towards methanol oxidation was examined by cyclic voltammetry. The measurements indicated that the catalytic activity was superior to conventional bare Pd nanoparticles. As confirmed by electron microscopy imaging and supported by density-functional theory (DFT) calculations, we attribute the improved catalytic performance primarily to inhibition of Pd core sintering during the catalytic process by the metal-oxide shell.We report on the design and synthesis of high performance catalytic nanoparticles with a robust geometry via magnetron-sputter inert-gas condensation. Sputtering of Pd and Mg from two independent neighbouring targets enabled heterogeneous condensation and growth of nanoparticles with controlled Pd core-MgO porous shell structure. The thickness of the shell and the number of cores within each nanoparticle could be tailored by adjusting the respective sputtering powers. The nanoparticles were directly deposited on glassy carbon electrodes, and their catalytic activity towards methanol oxidation was examined by cyclic voltammetry. The measurements indicated that the catalytic activity was superior to conventional bare Pd nanoparticles. As confirmed by electron microscopy imaging and supported by density-functional theory (DFT) calculations, we attribute the improved catalytic performance primarily to inhibition of Pd core sintering during the catalytic process by the metal-oxide shell

  8. Microbubbles with a Self-Assembled Poloxamer Shell and a Fluorocarbon Inner Gas.

    PubMed

    Ando, Yu; Tabata, Hiraku; Sanchez, Michaël; Cagna, Alain; Koyama, Daisuke; Krafft, Marie Pierre

    2016-11-29

    The numerous applications of microbubbles in food science and medicine call for a better understanding and control of the effects of the properties of their shells on their stability and ability to resonate at chosen frequencies when submitted to an ultrasound field. We have investigated both millimetric and micrometric bubbles stabilized by an amphiphilic block copolymer, Poloxamer 188 (e.g., Pluronic F-68). Although Pluronic F-68 is routinely being used as a dispersing and foaming agent to facilitate phospholipid-based microbubble preparation, it has never been studied as a shell component per se. First, we investigated the adsorption kinetics of Pluronic F-68 at the interface between water and air, or air saturated with vapors of perfluorohexane (F-hexane), using bubble profile tensiometry analysis. F-Hexane was found to strongly accelerate the adsorption of Pluronic F-68 (at low concentrations) and decrease the interfacial tension values at equilibrium (at all concentrations). We also found that relatively stable microbubbles could unexpectedly be prepared from Pluronic F-68 in the absence of any other surfactant, but only when F-hexane was present. These bubbles showed an only limited volume increase over ∼3 h, while a 10-fold increase in size occurred within 200 s in the absence of a fluorocarbon. Remarkably, their deflation rate decreased when the Pluronic F-68 concentration decreased, suggesting that bubbles with semidilute copolymer coverage are more stable than those more densely covered by copolymer brushes. Single-bubble experiments using laser Doppler vibratometry showed that, by contrast with other surfactant-coated microbubbles, the resonance radius of the Pluronic F-68-coated microbubbles was lower than that of naked microbubbles, meaning that they are less elastic. It was also found that the bubble's vibrational displacement amplitude decreased substantially when the microbubbles were covered with Pluronic F-68, an effect that was further

  9. Room-Temperature Ordered Photon Emission from Multiexciton States in Single CdSe Core-Shell Nanocrystals

    NASA Astrophysics Data System (ADS)

    Fisher, Brent; Caruge, Jean Michel; Zehnder, Don; Bawendi, Moungi

    2005-03-01

    We report room-temperature ordered multiphoton emission from multiexciton states of single CdSe(CdZnS) core(-shell) colloidal nanocrystals (NCs) that are synthesized by wet chemical methods. Spectrally and temporally resolved measurements of biexciton and triexciton emission from single NCs are also presented. A simple four level system models the results accurately and provides estimates for biexciton and triexciton radiative lifetimes and quantum yields.

  10. Room-temperature ordered photon emission from multiexciton states in single CdSe core-shell nanocrystals.

    PubMed

    Fisher, Brent; Caruge, Jean Michel; Zehnder, Don; Bawendi, Moungi

    2005-03-04

    We report room-temperature ordered multiphoton emission from multiexciton states of single CdSe(CdZnS) core(-shell) colloidal nanocrystals (NCs) that are synthesized by wet chemical methods. Spectrally and temporally resolved measurements of biexciton and triexciton emission from single NCs are also presented. A simple four level system models the results accurately and provides estimates for biexciton and triexciton radiative lifetimes and quantum yields.

  11. Characterizing Solids in Residual Wastes from Single-Shell Tanks at the Hanford Site.

    SciTech Connect

    Krupka, Kenneth M.; Cantrell, Kirk J.; Schaef, Herbert T.; Arey, Bruce W.; Heald, Steve M.; Deutsch, William J.; Lindberg, Michael J.

    2010-03-03

    Solid-phase characterization methods have been used in an ongoing study of residual wastes (i.e., waste remaining after final retrieval operations) from underground single-shell storage tanks 241-C-103, 241 C 106, 241-C-202, 241-C-203, and 241-S-112 at the U.S. Department of Energy’s Hanford Site in Washington State. The results of studies completed to date show variability in the compositions of those residual wastes and the compositions, morphologies, and crystallinities of the individual phases that make up these wastes. These differences undoubtedly result from the various waste types stored and transferred into and out of each tank and the different sluicing and retrieval operations used for waste retrieval. The studies indicate that these residual wastes are chemically-complex assemblages of crystalline and amorphous solids that contain contaminants as discrete phases and/or coprecipitated within oxide/hydroxide phases. Depending on the specific tank, various solids (e.g., gibbsite; böhmite; dawsonite; cancrinite; Fe oxides/hydroxides such as hematite, goethite, and maghemite; rhodochrosite; lindbergite; whewellite; nitratine; and numerous amorphous or poorly crystalline phases) have been identified by X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy in residual wastes studied to date. The studies also show that contact of residual wastes with Ca(OH)2- and CaCO3-saturated aqueous solutions, which were used as surrogates for the compositions of pore-fluid leachants derived from young and aged cements, respectively, may alter the composition of solid phases present in the contacted wastes. Iron oxides/hydroxides have been identified in all residual wastes studied to date. They occur in these wastes as discrete particles, particles intergrown within a matrix of other phases, and surface coatings on other particles or particle aggregates. These Fe oxides/hydroxides typically contain trace concentrations of other

  12. Limit Load and Buckling Analysis for Assessing Hanford Single-Shell Tank Dome Structural Integrity - 12278

    SciTech Connect

    Johnson, Ken I.; Deibler, John E.; Karri, Naveen K.; Pilli, Siva P.; Julyk, Larry J.

    2012-07-01

    The U.S. Department of Energy, Office of River Protection has commissioned a structural analysis of record for the Hanford single shell tanks to assess their structural integrity. The analysis used finite element techniques to predict the tank response to the historical thermal and operating loads. The analysis also addressed the potential tank response to a postulated design basis earthquake. The combined response to static and seismic loads was then evaluated against the design requirements of American Concrete Institute standard, ACI-349-06, for nuclear safety-related concrete structures. Further analysis was conducted to estimate the plastic limit load and the elastic-plastic buckling capacity of the tanks. The limit load and buckling analyses estimate the margin between the applied loads and the limiting load capacities of the tank structure. The potential for additional dome loads from waste retrieval equipment and the addition of large dome penetrations to accommodate retrieval equipment has generated additional interest in the limit load and buckling analyses. This paper summarizes the structural analysis methods that were used to evaluate the limit load and buckling of the single shell tanks. This paper summarizes the structural analysis methods that were used to evaluate the limit load and buckling limit states of the underground single shell tanks at the Hanford site. The limit loads were calculated using nonlinear finite element models that capture the progressive deformation and damage to the concrete as it approaches the limit load. Both uniform and concentrated loads over the tank dome were considered, and the analysis shows how adding a penetration in the center of the tank would affect the limit loads. For uniform surface loads, the penetration does not affect the limit load because concrete crushing and rebar yielding initiates first at the top of the wall, away from the penetration. For concentrated loads, crushing initiates at the center of the

  13. Enhanced performance of core-shell structured polyaniline at helical carbon nanotube hybrids for ammonia gas sensor

    NASA Astrophysics Data System (ADS)

    Tian, Xin; Wang, Qiang; Chen, Xiangnan; Yang, Weiqing; Wu, Zuquan; Xu, Xiaoling; Jiang, Man; Zhou, Zuowan

    2014-11-01

    A core-shell structured hybrid of polyaniline at helical carbon nanotubes was synthesized using in situ polymerization, which the helical carbon nanotubes were uniformly surrounded by a layer of polyaniline nanorods array. More interestingly, repeatable responses were experimentally observed that the sensitivity to ammonia gas of the as-prepared helical shaped core-shell hybrid displays an enhancement of more than two times compared to those of only polyaniline or helical carbon nanotubes sensors because of the peculiar structures with high surface area. This kind of hybrid comprising nanorod arrays of conductive polymers covering carbon nanotubes and related structures provide a potential in sensors of trace gas detection for environmental monitoring and safety forecasting.

  14. Enhanced performance of core-shell structured polyaniline at helical carbon nanotube hybrids for ammonia gas sensor

    SciTech Connect

    Tian, Xin; Wang, Qiang; Chen, Xiangnan; Yang, Weiqing; Xu, Xiaoling E-mail: bihan-2001@163.com; Jiang, Man; Zhou, Zuowan E-mail: bihan-2001@163.com; Wu, Zuquan

    2014-11-17

    A core-shell structured hybrid of polyaniline at helical carbon nanotubes was synthesized using in situ polymerization, which the helical carbon nanotubes were uniformly surrounded by a layer of polyaniline nanorods array. More interestingly, repeatable responses were experimentally observed that the sensitivity to ammonia gas of the as-prepared helical shaped core-shell hybrid displays an enhancement of more than two times compared to those of only polyaniline or helical carbon nanotubes sensors because of the peculiar structures with high surface area. This kind of hybrid comprising nanorod arrays of conductive polymers covering carbon nanotubes and related structures provide a potential in sensors of trace gas detection for environmental monitoring and safety forecasting.

  15. LESSONS LEARNED FROM PREVIOUS WASTE STORAGE TANK VAPOR CONTROL ATTEMPTS ON SINGLE SHELL TANK (SST) & DOUBLE SHELL TANK (DST) FARMS

    SciTech Connect

    BAKER, D.M.

    2004-08-03

    This report forms the basis for a feasibility study and conceptual design to control vapor emissions from waste storage tanks at the Hanford Site. The Carbtrol, Vapor Mixing, and High Efficiency Gas Absorber (HEGA) vapor controls were evaluated to determine the lessons learned from previous failed vapor control attempts. This document illustrates the resulting findings based on that evaluation.

  16. Single shaft automotive gas turbine engine characterization test

    NASA Technical Reports Server (NTRS)

    Johnson, R. A.

    1979-01-01

    An automotive gas turbine incorporating a single stage centrifugal compressor and a single stage radial inflow turbine is described. Among the engine's features is the use of wide range variable geometry at the inlet guide vanes, the compressor diffuser vanes, and the turbine inlet vanes to achieve improved part load fuel economy. The engine was tested to determine its performance in both the variable geometry and equivalent fixed geometry modes. Testing was conducted without the originally designed recuperator. Test results were compared with the predicted performance of the nonrecuperative engine based on existing component rig test maps. Agreement between test results and the computer model was achieved.

  17. Experimental Results from Plasma Shell on Deuterium Gas-puff Z-pinch on the Current Level of 3 MA

    NASA Astrophysics Data System (ADS)

    Rezac, K.; Klir, D.; Kubes, P.; Kravarik, J.; Shishlov, A.; Labetsky, A.; Kokshenev, V.; Ratakhin, N.; GIT-12 Team

    2013-10-01

    The experiments with a plasma shell on deuterium gas-puff Z-pinch were carried out on the GIT-12 generator at IHCE in Tomsk. We diagnosed Z-pinch shots with deuterium linear mass of about 100 μg/cm. The outer shell of the load was formed by 48 plasma guns positioned on diameter of 350 mm, the diameter of the nozzle producing deuterium inner shell gas-puff was 80 mm. Results obtained from X-ray and neutron diagnostics, especially neutron time-of-flight signals, where 15 MeV neutrons (in radial direction) and 22 MeV neutrons (in axial direction) were registered, are presented. Obtained implosion velocity of the gas-puff had the value of 4 . 5 ×107 cm/s, neutron yield from D(d,n)3He reaction was in order of 1012 neutrons/shot on a current level of about 2.7 MA. The time correlations of the TOF diagnostics with other diagnostics such as electrical characteristics, an MCP frames, and a visible streak camera are also presented. Work supported by MEYS CR research programs No. ME090871, No. LG13029, by GACR grant No. P205/12/0454, grant CRA IAEA No. 17088 and RFBR research project No. 13-08-00479-a.

  18. Shell Model Approach to Nuclear Level Density

    NASA Astrophysics Data System (ADS)

    Horoi, Mihai

    2000-04-01

    Nuclear level densities (NLD) are traditionally estimated using variations of Fermi Gas Formula (FGF) or combinatoric techniques. Recent investigations using Monte Carlo Shell Model (MCSM) techniques indicate that a shell model description of NLD may be an accurate and stable approach. Full shell model calculations of NLD are very difficult. We calculated the NLD for all nuclei in the sd shell and show that the results can be described by a single particle combinatoric model, which depends on two parameters similar to FGF. We further investigated other models and find that a sum of gaussians with means and variances given by French and Ratcliff averages (Phys. Rev. C 3, 94(1971)) is able to accurately describe shell model NLD, even when shell effects are present. The contribution of the spurious center-of-mass motion to the shell model NLD is also discussed.

  19. Fabrication and NO2 gas sensing performance of TeO2-core/CuO-shell heterostructure nanorod sensors

    PubMed Central

    2014-01-01

    TeO2-nanostructured sensors are seldom reported compared to other metal oxide semiconductor materials such as ZnO, In2O3, TiO2, Ga2O3, etc. TeO2/CuO core-shell nanorods were fabricated by thermal evaporation of Te powder followed by sputter deposition of CuO. Scanning electron microscopy and X-ray diffraction showed that each nanorod consisted of a single crystal TeO2 core and a polycrystalline CuO shell with a thickness of approximately 7 nm. The TeO2/CuO core-shell one-dimensional (1D) nanostructures exhibited a bamboo leaf-like morphology. The core-shell nanorods were 100 to 300 nm in diameter and up to 30 μm in length. The multiple networked TeO2/CuO core-shell nanorod sensor showed responses of 142% to 425% to 0.5- to 10-ppm NO2 at 150°C. These responses were stronger than or comparable to those of many other metal oxide nanostructures, suggesting that TeO2 is also a promising sensor material. The responses of the core-shell nanorods were 1.2 to 2.1 times higher than those of pristine TeO2 nanorods over the same NO2 concentration range. The underlying mechanism for the enhanced NO2 sensing properties of the core-shell nanorod sensor can be explained by the potential barrier-controlled carrier transport mechanism. PACS 61.46. + w; 07.07.Df; 73.22.-f PMID:25489289

  20. Regulatory Closure Options for the Residue in the Hanford Site Single-Shell Tanks

    SciTech Connect

    Cochran, J.R. Shyr, L.J.

    1998-10-05

    Liquid, mixed, high-level radioactive waste (HLW) has been stored in 149 single-shell tanks (SSTS) located in tank farms on the U.S. Department of Energy's (DOE's) Hanford Site. The DOE is developing technologies to retrieve as much remaining HLW as technically possible prior to physically closing the tank farms. In support of the Hanford Tanks Initiative, Sandia National Laboratories has addressed the requirements for the regulatory closure of the radioactive component of any SST residue that may remain after physical closure. There is significant uncertainty about the end state of each of the 149 SSTS; that is, the nature and amount of wastes remaining in the SSTS after retrieval is uncertain. As a means of proceeding in the face of these uncertainties, this report links possible end-states with associated closure options. Requirements for disposal of HLW and low-level radioactive waste (LLW) are reviewed in detail. Incidental waste, which is radioactive waste produced incidental to the further processing of HLW, is then discussed. If the low activity waste (LAW) fraction from the further processing of HLW is determined to be incidental waste, then DOE can dispose of that incidental waste onsite without a license from the U.S. Nuclear Regulatory Commissions (NRC). The NRC has proposed three Incidental Waste Criteria for determining if a LAW fraction is incidental waste. One of the three Criteria is that the LAW fraction should not exceed the NRC's Class C limits.

  1. RCRA Assessment Plan for Single-Shell Tank Waste Management Area TX-TY

    SciTech Connect

    Horton, Duane G.

    2007-03-26

    WMA TX-TY contains underground, single-shell tanks that were used to store liquid waste that contained chemicals and radionuclides. Most of the liquid has been removed, and the remaining waste is regulated under the RCRA as modi¬fied in 40 CFR Part 265, Subpart F and Washington State’s Hazardous Waste Management Act . WMA TX-TY was placed in assessment monitoring in 1993 because of elevated specific conductance. A groundwater quality assessment plan was written in 1993 describing the monitoring activities to be used in deciding whether WMA TX-TY had affected groundwater. That plan was updated in 2001 for continued RCRA groundwater quality assessment as required by 40 CFR 265.93 (d)(7). This document further updates the assessment plan for WMA TX-TY by including (1) information obtained from ten new wells installed at the WMA after 1999 and (2) information from routine quarterly groundwater monitoring during the last five years. Also, this plan describes activities for continuing the groundwater assessment at WMA TX TY.

  2. Tank characterization report for single-shell tank 241-BX-110

    SciTech Connect

    RASMUSSEN, J.H.

    1999-02-23

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report (TCR). This report and its appendices serve as the TCR for single-shell tank 241-BX-110. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-BX-110 waste, and (2) to provide a standard characterization of the waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, and Section 4.0 makes recommendations about the tank's safety status and additional sampling needs. The appendices contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15b, change request M-44-97-03 to ''issue characterization deliverables consistent with the Waste Information Requirements Document developed for 1998.''

  3. Tank characterization report for single-shell tank 241-AX-102

    SciTech Connect

    FIELD, J.G.

    1999-05-12

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report (TCR). This report and its appendices serve as the TCR for single-shell tank 241-AX-102. The objectives of this report are: (1) to use characterization data in response to technical issues associated with tank 241-AX-102 waste, and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, Section 4.0 makes recommendations about the safety status of the tank and additional sampling needs. The appendices contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15c, change request M-44-97-03 to ''issue characterization deliverables consistent with the Waste Information Requirements Document developed for FY 1999'' (Adams et al. 1998).

  4. Task analysis for the single-shell Tank Waste Retrieval Manipulator System

    SciTech Connect

    Draper, J.V.

    1993-03-01

    This document describes a task analysis for the Tank Waste Retrieval Manipulator System. A task analysis is a formal method of examining work that must be done by the operators of human-machine systems. The starting point for a task analysis is the mission that a human-machine system must perform, and the ending point is a list of requirements for human actions and the displays and controls that must be provided to support them. The task analysis approach started with a top-down definition of the steps in a tank retrieval campaign. It started by dividing a waste retrieval campaign for one single-shell tank into the largest logical components (mission phases), then subdivided these into secondary components (sub functions), and then further subdivided the secondary components into tertiary units (tasks). Finally, the tertiary units were divided into potentially observable operator behaviors (task elements). In the next stage of the task analysis, the task elements were evaluated by completing an electronic task analysis form patterned after one developed by the Nuclear Regulatory Commission for task analysis of nuclear power plant control rooms. In the final stage, the task analysis data base was used in a bottom-up approach to develop clusters of controls and displays called panel groups and to prioritize these groups for each subfunction. Panel groups are clusters of functionally related controls and displays. Actual control panels will be designed from panel groups, and panel groups will be organized within workstations to promote efficient operations during retrieval campaigns.

  5. Tank characterization report for single-shell tak 241-C-112. Revision 1

    SciTech Connect

    Simpson, B.C.

    1997-06-11

    One major function of the Tank Waste Remediation System (IWRS) is to characterize wastes in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report (CR). This report and its appendixes serve as the CR for single-shell tank 24 1 -C- 1 12. The objectives of this report are: 1) to use characterization data in response to technical issues associated with tank 24 1 -C- 1 12 waste, and 2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, and Section 4.0 makes recommendations regarding safety status and additional sampling needs. The appendixes contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order, Milestone M-44-05 (Ecology et al. 1996).

  6. Tank characterization report for single-shell tank 241-SX-106

    SciTech Connect

    FIELD, J.G.

    1999-02-24

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report. This report and its appendices serve as the tank characterization report for single-shell tank 241-SX-106. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-SX-106 waste and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, Section 4.0 makes recommendations about the safety status of the tank and additional sampling needs. The appendices contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15b, change request M-44-97-03 to ''issue characterization deliverables consistent with the Waste Information Requirements Documents developed for 1998.''

  7. Tank characterization report for single-shell tank 241-SX-115

    SciTech Connect

    HULSE, N.L.

    1999-05-13

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report (TCR). This report and its appendices serve as the TCR for single-shell tank 241-SX-115. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-SX-115 waste, and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, Section 4.0 makes recommendations about the safety status of the tank and additional sampling needs. The appendices contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15c, change request M-44-97-03 to ''issue characterization deliverables consistent with the Waste Information Requirements Document developed for FY 1999'' (Adams et al. 1998).

  8. Tank characterization report for single-shell tank 241-TX-104

    SciTech Connect

    FIELD, J.G.

    1999-05-12

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report (TCR). This report and its appendices serve as the TCR for single-shell tank 241-TX-104. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-TX-104 waste, and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, Section 4.0 makes recommendations about the safety status of the tank and additional sampling needs. The appendices contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15c, change request M-44-97-03 to ''issue characterization deliverables consistent with the Waste Information Requirements Document developed for FY 1999'' (Adams et al. 1998).

  9. Tank characterization report for single-shell tank 241-T-112

    SciTech Connect

    McCain, D.J.

    1998-06-11

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report (TCR). This report and its appendices serve as the TCR for single-shell tank 241-T-112. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-T-112 waste and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, Section 4.0 makes recommendations about the safety status of the tank and additional sampling needs. The appendices contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15b, change request M-44-97-03, to ``issue characterization deliverables consistent with the Waste Information Requirements Documents developed for 1998.``

  10. Tank characterization report for single-shell tank 241-U-112

    SciTech Connect

    Field, J.G.

    1998-05-28

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report (TCR). This report and its appendixes serve as the TCR for single-shell tank 241-U-112. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-U-112 waste, and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, Section 4.0 makes recommendations about the safety status of the tank and additional sampling needs. The appendixes contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15b, change request M-44-97-03 to issue characterization deliverables consistent with the Waste Information Requirements Document developed for 1998.

  11. Tank characterization report for single-shell tank 241-U-103

    SciTech Connect

    SASAKI, L.M.

    1999-02-24

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report. This report and its appendices serve as the tank characterization report for single-shell tank 241-U-103. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-U-103 waste and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, Section 4.0 makes recommendations about the safety status of the tank and additional sampling needs. The appendices contain supporting data and information. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15b, change request M-44-97-03 to ''issue characterization deliverables consistent with Waste Information Requirements Documents developed for 1998.''

  12. Retrieval Of Hanford's Single Shell Nuclear Waste Tanks Using Technologies Foreign And Domestic

    SciTech Connect

    Eacker, J. A.; Thompson, W. T.; Gibbons, P. W.

    2003-02-26

    Significant progress has been made on the Hanford single shell tank (SST) retrieval projects since they were initiated as part of the modified Hanford Federal Facility Agreement and Consent Order (Tri-party Agreement) in 2000. Four of the 149 SSTs at the U.S. Department of Energy (DOE) Office of River Protection (ORP) Hanford facility are being retrieved to meet Tri-Party Agreement commitments. An additional tank is being retrieved to demonstrate an alternate technical approach. As the Hanford Site transitions to an accelerated retrieval and closure mission, these methods will be the baseline methods for SST retrieval. The five SSTs are located within the Hanford 200- Area tank farms operated by CH2M HILL Hanford Group (CH2M HILL) for ORP. Included in this paper will be discussions on the technologies selected for retrieval of each tank; electrical resistance technologies that are being evaluated for ex-tank leak detection and monitoring; and the Cold Test Training Facility (CTTF) used for testing of and training on the different retrieval systems.

  13. Tank Characterization report for single-shell tank 241-SX-103

    SciTech Connect

    WILMARTH, S.R.

    1999-05-20

    A major function of the Tank Waste Remediation System (TWRS) is to characterize waste in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis and other available information about a tank are compiled and maintained in a tank characterization report. This report and its appendices serve as the tank characterization report for single-shell tank 241-SX-103. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-SX-103 waste, and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 summarizes the response to technical issues, Section 3.0 shows the best-basis inventory estimate, and Section 4.0 makes recommendations about the safety status of the tank and additional sampling needs. The appendices contain supporting data and information. This report supports the requirements of Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1997), Milestone M-44-15c, change request M-44-97-03 to ''issue characterization deliverables consistent with the Waste Information Requirements Document developed for fiscal year 1999'' (Adams et al. 1998).

  14. Preliminary assessment of candidate immobilization technologies for retrieved single-shell tank wastes

    SciTech Connect

    Wiemers, K.D.; Mendel, J.E.; Kruger, A.A.; Bunnell, L.R.; Mellinger, G.B.

    1992-01-01

    This report describes the initial work that has been performed to select technologies for immobilization of wastes that may be retrieved from Hanford single-shell tanks (SSTs). Two classes of waste will require immobilization. One is the combined high-level waste/transuranic (HLW/TRU) fraction, the other the low-level waste (LLW) fraction. A number of potential immobilization technologies are identified for each class of waste. Immobilization technologies were initially selected based on a number of considerations, including (1) the waste loading that could likely be achieved within the constraint of producing acceptable waste forms, (2) process flexibility (primarily compatibility with anticipated waste variability), (3) process complexity, and (4) state of development. Immobilization technologies selected for further development include the following: for HLW/TRU waste -- borosilicate glass, lead-iron phosphate glass, glass-calcine composites, glass-ceramics, and cement based forms; for non-denitrated LLW -- grout, laxtex-modified concrete, and polyethylene; and for denitrated LLW -- silicate glass, phosphate glass, and clay calcination or tailored ceramic in various matrices.

  15. Single-shell tank constituent rankings for use in preparing waste characterization plans

    SciTech Connect

    Droppo, J.G. Jr.; Buck, J.W.; Wilbur, J.S.; Strenge, D.L.; Freshley, M.D.

    1991-06-01

    Waste characterization efforts for underground single-shell tanks (SSTs) containing chemical and radioactive mixed wastes at the US Department of Energy's (DOE) Hanford Site are currently under way. As a component of this effort, an analysis was conducted to give a preliminary ranking of possible constituents in the SST waste and provide data for establishing detection limit requirements for the SST characterization effort. These SST constituent rankings were based on a relative comparison using potential human health impacts modeled using a hypothetical exposure scenario. This modeling effort used preliminary estimates of the SST inventories, simplified estimates of constituent release rates and environmental transport, a hypothetical usage location, and a standard Hanford exposure scenario. The results of this evaluation are SST constitutents for each of six groups of SSTs ranked according to their relative potential for impacts. The relative rankings for different recharge rates at the tank farms were nearly equivalent. Sensitivity tests demonstrated that the rankings are influenced by changes in recharge and transport parameters. 45 refs., 18 figs., 2 tabs.

  16. Functions and requirements for Hanford single-shell tank leakage detection and monitoring

    SciTech Connect

    Cruse, J.M.; Ohl, P.C.

    1995-04-19

    This document provides the initial functions and requirements for leakage detection and monitoring applicable to past and potential future leakage from the Hanford Site`s 149 single-shell high-level waste tanks. This mission is a part of the overall mission of the Westinghouse Hanford Company Tank Waste Remediation System division to remediate the tank waste in a safe and acceptable manner. Systems engineering principles are being applied to this effort. This document reflects the an initial step in the systems engineering approach to decompose the mission into primary functions and requirements. The document is considered approximately 30% complete relative to the effort required to produce a final version that can be used to support demonstration and/or procurement of technologies. The functions and requirements in this document apply to detection and monitoring of below ground leaks from SST containment boundaries and the resulting soil contamination. Leakage detection and monitoring is invoked in the TWRS Program in three fourth level functions: (1) Store Waste, (2) Retrieve Waste, and (3) Disposition Excess Facilities (as identified in DOE/RL-92-60 Rev. 1, Tank Waste Remediation System Functions and Requirements).

  17. Architecture, implementation, and testing of a multiple-shell gas injection system for high current implosions on the Z accelerator.

    PubMed

    Krishnan, Mahadevan; Elliott, Kristi Wilson; Madden, Robert E; Coleman, P L; Thompson, John R; Bixler, Alex; Lamppa, D C; McKenney, J L; Strizic, T; Johnson, D; Johns, O; Vigil, M P; Jones, B; Ampleford, D J; Savage, M E; Cuneo, M E; Jones, M C

    2013-06-01

    Tests are ongoing to conduct ~20 MA z-pinch implosions on the Z accelerator at Sandia National Laboratory using Ar, Kr, and D2 gas puffs as the imploding loads. The relatively high cost of operations on a machine of this scale imposes stringent requirements on the functionality, reliability, and safety of gas puff hardware. Here we describe the development of a prototype gas puff system including the multiple-shell nozzles, electromagnetic drivers for each nozzle's valve, a UV pre-ionizer, and an inductive isolator to isolate the ~2.4 MV machine voltage pulse present at the gas load from the necessary electrical and fluid connections made to the puff system from outside the Z vacuum chamber. This paper shows how the assembly couples to the overall Z system and presents data taken to validate the functionality of the overall system.

  18. Architecture, implementation, and testing of a multiple-shell gas injection system for high current implosions on the Z accelerator

    NASA Astrophysics Data System (ADS)

    Krishnan, Mahadevan; Elliott, Kristi Wilson; Madden, Robert E.; Coleman, P. L.; Thompson, John R.; Bixler, Alex; Lamppa, D. C.; McKenney, J. L.; Strizic, T.; Johnson, D.; Johns, O.; Vigil, M. P.; Jones, B.; Ampleford, D. J.; Savage, M. E.; Cuneo, M. E.; Jones, M. C.

    2013-06-01

    Tests are ongoing to conduct ˜20 MA z-pinch implosions on the Z accelerator at Sandia National Laboratory using Ar, Kr, and D2 gas puffs as the imploding loads. The relatively high cost of operations on a machine of this scale imposes stringent requirements on the functionality, reliability, and safety of gas puff hardware. Here we describe the development of a prototype gas puff system including the multiple-shell nozzles, electromagnetic drivers for each nozzle's valve, a UV pre-ionizer, and an inductive isolator to isolate the ˜2.4 MV machine voltage pulse present at the gas load from the necessary electrical and fluid connections made to the puff system from outside the Z vacuum chamber. This paper shows how the assembly couples to the overall Z system and presents data taken to validate the functionality of the overall system.

  19. In-flight gas phase growth of metal/multi layer graphene core shell nanoparticles with controllable sizes

    PubMed Central

    Sengar, Saurabh K.; Mehta, B. R.; Kumar, Rakesh; Singh, Vinod

    2013-01-01

    In this report, we present a general method for a continuous gas-phase synthesis of size-selected metal/multi layer graphene (MLG) core shell nanoparticles having a narrow size distribution of metal core and MLG shell for direct deposition onto any desired substrate kept under clean vacuum conditions. Evolution of MLG signature is clearly observed as the metal-carbon agglomerates get transformed to well defined metal/MLG core shell nanoparticles during their flight through the sintering zone. The growth takes place via an intermediate state of alloy nanoparticle (Pd-carbon) or composite nanoparticle (Cu-carbon), depending upon the carbon solubility in the metal and relative surface energy values. It has been also shown that metal/MLG nanoparticles can be converted to graphene shells. This study will have a large impact on how graphene or graphene based composite nanostructures can be grown and deposited in applications requiring controllable dimensions, varied substrate choice, large area and large scale depositions. PMID:24100702

  20. Review of high convergence implosion experiments with single and double shell targets

    SciTech Connect

    Delamater, N. D.; Watt, R. G.; Varnum, W. S.

    2002-01-01

    Experiments have been been performed in recent years at the Omega laser studying double shell capsules as an a1 teinative, 11011 cryogenic, path towards ignition at NTF. Double shell capsules designed to mitigate the Au M-band radiation asymmetries, were experimentally found to perform well in both spherical and cylindrical hohlraums, achieving near 1-D (-90 %) clean calculated yield at convergence comparable to that required for NIF ignition. Near-term plans include directly driven double shell experiments at Omega, which eliminates Au M-band radiation as a yield degradation m ec h an i s in.

  1. Refinement of Modeling Techniques for the Structural Evaluation of Hanford Single-Shell Nuclear Waste Storage Tanks - 12288

    SciTech Connect

    Karri, Naveen K.; Rinker, Michael W.; Johnson, Kenneth I.; Bapanapalli, Satish K.

    2012-07-01

    The single-shell tanks at the Hanford Site (in Washington State, USA) were constructed between 1943 and 1964 and are well beyond their estimated 25 year design life. This article discusses the structural analysis approach and modeling challenges encountered during the ongoing analysis of record for evaluating the structural integrity of the single-shell tanks. There are several geometrical and material nonlinearities and uncertainties to be dealt with while performing the modern finite element analysis of these tanks. The analysis takes into account the temperature history of the tanks and allowable mechanical operating loads for proper estimation of creep strains and thermal degradation of material properties. The loads prescribed in the analysis of record models also include anticipated loads that may occur during waste retrieval and closure. Due to uncertainty in a number of modeling details, sensitivity studies were conducted to address questions related to boundary conditions that realistically or conservatively represent the influence of surrounding tanks in a tank farm, the influence of backfill excavation slope, the extent of backfill and the total extent of undisturbed soil surrounding the backfill. Because of the limited availability of data on the thermal and operating history for many of the individual tanks, some of the data was assumed or interpolated. However, the models developed for the analysis of record represent the bounding scenarios and include the loading conditions that the tanks were subjected to or anticipated. The modeling refinement techniques followed in the analysis of record resulted in conservative estimates for force and moment demands at various sections in the concrete tanks. This article discusses the modeling aspects related to Type-II and Type-III single-shell tanks. The modeling techniques, methodology and evaluation criteria developed for evaluating the structural integrity of single-shell tanks at Hanford are in general

  2. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation

    NASA Astrophysics Data System (ADS)

    Xing, Lijuan; ten Brink, Gert H.; Chen, Bin; Schmidt, Franz P.; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J.; Palasantzas, George

    2016-05-01

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core-shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment. Moreover, extensive analysis showed that NPs with a size between 10-20 nm possess a truncated cubic morphology, which is confined by the 6 {100} planes that are truncated by the 12 {110} planes at different degrees. For NPs larger than 20 nm, the rhombic dodecahedron defined by the 12 {110} planes is the predominant crystal shape, while truncated rhombic dodecahedrons, as well as non-truncated and truncated cubic NPs, were also observed. The NPs without truncation showed a characteristic inward relaxation indicating that besides thermodynamics kinetics also plays a crucial role during particle growth.

  3. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation.

    PubMed

    Xing, Lijuan; Ten Brink, Gert H; Chen, Bin; Schmidt, Franz P; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J; Palasantzas, George

    2016-05-27

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core-shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment. Moreover, extensive analysis showed that NPs with a size between 10-20 nm possess a truncated cubic morphology, which is confined by the 6 {100} planes that are truncated by the 12 {110} planes at different degrees. For NPs larger than 20 nm, the rhombic dodecahedron defined by the 12 {110} planes is the predominant crystal shape, while truncated rhombic dodecahedrons, as well as non-truncated and truncated cubic NPs, were also observed. The NPs without truncation showed a characteristic inward relaxation indicating that besides thermodynamics kinetics also plays a crucial role during particle growth.

  4. Pinning and gas oversaturation imply stable single surface nanobubbles

    NASA Astrophysics Data System (ADS)

    Lohse, Detlef; Zhang, Xuehua

    2015-03-01

    Surface nanobubbles are experimentally known to survive for days at hydrophobic surfaces immersed in gas-oversaturated water. This is different from bulk nanobubbles, which are pressed out by the Laplace pressure against any gas oversaturation and dissolve in submilliseconds, as derived by Epstein and Plesset [J. Chem. Phys. 18, 1505 (1950), 10.1063/1.1747520]. Pinning of the contact line has been speculated to be the reason for the stability of the surface nanobubbles. Building on an exact result by Popov [Phys. Rev. E 71, 036313 (2005), 10.1103/PhysRevE.71.036313] on coffee stain evaporation, here we confirm this speculation by an exact calculation for single surface nanobubbles. It is based only on (i) the diffusion equation, (ii) Laplace pressure, and (iii) Henry's equation, i.e., fluid dynamical equations which are all known to be valid down to the nanometer scale. The crucial parameter is the gas oversaturation ζ of the liquid. At the stable equilibrium, the gas overpressures due to this oversaturation and the Laplace pressure balance. The theory predicts how the contact angle of the pinned bubble depends on ζ and the surface nanobubble's footprint lateral extension L . It also predicts an upper lateral extension threshold for stable surface nanobubbles to exist.

  5. Contaminant Release from Residual Waste in Single Shell Tanks at the Hanford Site, Washington, USA - 9276

    SciTech Connect

    Cantrell, Kirk J.; Krupka, Kenneth M.; Deutsch, William J.; Lindberg, Michael J.

    2009-06-01

    Determinations of elemental and solid-phase compositions, and contaminant release studies have been applied in an ongoing study of residual tank wastes (i.e., waste remaining after final retrieval operations) from five of 149 underground single-shell storage tanks (241-C-103, 241-C-106, 241-C-202, 241-C-203, and 241-S-112) at the U.S. Department of Energy’s Hanford Site in Washington State. This work is being conducted to support performance assessments that will be required to evaluate long-term health and safety risks associated with tank site closure. The results of studies completed to date show significant variability in the compositions, solid phase properties, and contaminant release characteristics from these residual tank wastes. This variability is the result of differences in waste chemistry/composition of wastes produced from several different spent fuel reprocessing schemes, subsequent waste reprocessing to remove certain target constituents, tank farm operations that concentrated wastes and mixed wastes between tanks, and differences in retrieval processes used to remove the wastes from the tanks. Release models were developed based upon results of chemical characterization of the bulk residual waste, solid-phase characterization (see companion paper 9277 by Krupka et al.), leaching and extraction experiments, and geochemical modeling. In most cases empirical release models were required to describe contaminant release from these wastes. Release of contaminants from residual waste was frequently found to be controlled by the solubility of phases that could not be identified and/or for which thermodynamic data and/or dissolution rates have not been measured. For example, significant fractions of Tc-99, I-129, and Cr appear to be coprecipitated at trace concentrations in metal oxide phases that could not be identified unambiguously. In the case of U release from tank 241-C-103 residual waste, geochemical calculations indicated that leachate

  6. Data Package for Past and Current Groundwater Flow and Contamination beneath Single-Shell Tank Waste Management Areas

    SciTech Connect

    Horton, Duane G.

    2007-03-16

    This appendix summarizes historic and recent groundwater data collected from the uppermost aquifer beneath the 200 East and 200 West Areas. Although the area of interest is the Hanford Site Central Plateau, most of the information discussed in this appendix is at the scale of individual single-shell tank waste management areas. This is because the geologic, and thus the hydraulic, properties and the geochemical properties (i.e., groundwater composition) are different in different parts of the Central Plateau.

  7. Proposed strategy for leak detection, monitoring, and mitigation (LDMM) during Hanford single-shell tank waste retrieval

    SciTech Connect

    Iwatate, D.F., Westinghouse Hanford

    1996-07-08

    This document proposes a strategy to address issues related to leakage from single-shell tanks (SSTs) during sluicing. A set of criteria are proposed to capture the relevant issues pertaining to leak detection, monitoring, and mitigation (LDMM), and allow DOE-RL, the Contractor, Ecology, and Hanford Stakeholders to reach consensus on allowable leakage volumes (ALVs). Technical studies and findings that support the proposed strategy, and ALV criteria, are summarized and referenced. This document specifically addresses LDMM for SSTs at Hanford, Washington.

  8. Miniaturized ionization gas sensors from single metal oxide nanowires.

    PubMed

    Hernandez-Ramirez, Francisco; Prades, Juan Daniel; Hackner, Angelika; Fischer, Thomas; Mueller, Gerhard; Mathur, Sanjay; Morante, Joan Ramon

    2011-02-01

    Gas detection experiments were performed with individual tin dioxide (SnO2) nanowires specifically configured to observe surface ion (SI) emission response towards representative analyte species. These devices were found to work at much lower temperatures (T≈280 °C) and bias voltages (V≈2 V) than their micro-counterparts, thereby demonstrating the inherent potential of individual nanostructures in building functional nanodevices. High selectivity of our miniaturized sensors emerges from the dissimilar sensing mechanisms of those typical of standard resistive-type sensors (RES). Therefore, by employing this detection principle (SI) together with RES measurements, better selectivity than that observed in standard metal oxide sensors could be demonstrated. Simplicity and specificity of the gas detection as well as low-power consumption make these single nanowire devices promising technological alternatives to overcome the major drawbacks of solid-state sensor technologies.

  9. Borehole Data Package for 1998 Wells Installed at Single-Shell Tank Waste Management Area U

    SciTech Connect

    DG Horton; FN Hodges

    1999-03-23

    Two new Resource Conservation and Recovery Act (RCR4) groundwater monitoring wells were installed at the single-shell tank f- Waste Management Area (WMA) U in October 1998 in fi,dfillrnent of Tri-PaQy Agreement (Ecology 1996) milestone M-24-39. The wells are 299-W19-41 and 299-W19-42. Well 299-W19-41 is located east of the southeastern comer of the WMA and replaces downgradient well 299-W19-32. Well 299-W19-42 is located east of the WNIA near the northeastern comer and is a new downgradient monitoring well. The locations of all wells in the monitoring network are shown on Figure 1. The groundwater monitoring plan for WMA U (Caggiano and Goodwin 1991) describes the hydrogeology of the 200 West Area and WMA U. An Interim Change Notice to the groundwater monitoring plan provides justification for the new wells. The new wells were constructed to the specifications and requirements described in Washington Administrative Code (WAC) 173-160 and WAC 173-303. This document compiles Mormation on the drilling and Construction well development pump installation, and sedment testing applicable to wells 299-W19-41 and 299-W19-42. Appendix A contains the geologist's log, the Well Construction Summary Reportj and Well Summary Sheet (as-built diagram); Appendix B contains results of laboratory measurements of particle size distribution pm conductivity, and calcium carbonate and moisture contents; and Append~ C contains geophysical logs. Aquifer tests (slug tests) were pefiormed on both new wells. Results from the aquifer tests will be reported elsewhere. Additional documentation concerning well construction is on file with Bechtel Hanford, Inc., Richland Washington.

  10. Tank characterization report for Single-Shell Tank 241-BX-107

    SciTech Connect

    Raphael, G.F.

    1994-09-01

    This study examined and assessed the status, safety issues, composition, and distribution of the wastes contained in the tank 241-BX-107. Historical and most recent information, ranging from engineering structural assessment experiments, process history, monitoring and remediation activities, to analytical core sample data, were compiled and interpreted in an effort to develop a realistic, contemporary profile for the tank BX-107 contents. The results of this is study revealed that tank BX-107, a 2,006,050 L (530,000 gal) cylindrical single-shell, dished-bottom carbon-steel tank in the 200 East Area of the Hanford Site, was classified as sound. It has been interim stabilized and thus contains less than 189,250 L (50,000 gal) of interstitial liquid, and less than 18,925 L (5,000 gal) of supernatant. It has also been partially interim isolated, whereby all inlets to the tank are sealed to prevent inadvertent addition of liquid. At a residual waste level of {approximately}3.07 m (120.7 {+-} 2 in. from sidewall bottom or {approximately}132.9 in. from center bottom), it is estimated that the tank BX-107 contents are equivalent to 1,305,825 L (345,000 gal). The vapor space pressure is at atmospheric. The latest temperature readings, which were taken in July 1994, show a moderate temperature value of 19{degrees}C (66{degrees}F). Two supernatant samples were collected in 1974 and 1990, prior to interim stabilization. Sludge core samples were obtained in 1979 and 1992.

  11. FRACTIONAL CRYSTALLIZATION OF HANFORD SINGLE SHELL TANK (SST) WASTES FROM CONCEPT TO PILOT PLANT

    SciTech Connect

    GENIESSE, D.J.; NELSON, E.A.; HAMILTON, D.W.; MAJORS, J.H.; NORDAHL, T.K.

    2006-12-08

    The Hanford site has 149 underground single-shell tanks (SST) storing mostly soluble, multi-salt mixed wastes resulting from Cold War era weapons material production. These wastes must be retrieved and the salts immobilized before the tanks can be closed to comply with an overall site-closure consent order entered into by the US Department of Energy, the Environmental Protection Agency, and the State of Washington. Water will be used to retrieve the wastes and the resulting solution will be pumped to a proposed pretreatment process where a high-curie (primarily {sup 137}Cs) waste fraction will be separated from the other waste constituents. The separated waste streams will then be vitrified to allow for safe storage as an immobilized high-level waste, or low-level waste, borosilicate glass. Fractional crystallization, a common unit operation for production of industrial chemicals and pharmaceuticals, was proposed as the method to separate the salt wastes; it works by evaporating excess water until the solubilities of various species in the solution are exceeded (the solubility of a particular species depends on its concentration, temperature of the solution, and the presence of other ionic species in the solution). By establishing the proper conditions, selected pure salts can be crystallized and separated from the radioactive liquid phase. The aforementioned parameters, along with evaporation rate, proper agitation, and residence time, determine nucleation and growth kinetics and the resulting habit and size distribution of the product crystals. These crystals properties are important considerations for designing the crystallizer and solid/liquid separation equipment. A structured program was developed to (a) demonstrate that fractional crystallization could be used to pre-treat Hanford tank wastes and (b) provide data to develop a pilot plant design.

  12. Statistical characterization report for Single-Shell Tank 241-T-107

    SciTech Connect

    Cromar, R.D.; Wilmarth, S.R.; Jensen, L.

    1994-11-01

    This report contains the results of the statistical analysis of data from three core samples obtained from single-shell tank 241-T-107 (T-107). Four specific topics are addressed. They are summarized below. Section 3.0 contains mean concentration estimates of analytes found in T-107. The estimates of {open_quotes}error{close_quotes} associated with the concentration estimates are given as 95% confidence intervals (CI) on the mean. The results given are based on three types of samples: core composite samples, core segment samples, and drainable liquid samples. Section 4.0 contains estimates of the spatial variability (variability between cores and between segments) and the analytical variability (variability between the primary and the duplicate analysis). Statistical tests were performed to test the hypothesis that the between cores and the between segments spatial variability is zero. The results of the tests are as follows. Based on the core composite data, the between cores variance is significantly different from zero for 35 out of 74 analytes; i.e., for 53% of the analytes there is no statistically significant difference between the concentration means for two cores. Based on core segment data, the between segments variance is significantly different from zero for 22 out of 24 analytes and the between cores variance is significantly different from zero for 4 out of 24 analytes; i.e., for 8% of the analytes there is no statistically significant difference between segment means and for 83% of the analytes there is no difference between the means from the three cores. Section 5.0 contains the results of the application of multiple comparison methods to the core composite data, the core segment data, and the drainable liquid data. Section 6.0 contains the results of a statistical test conducted to determine the 222-S Analytical Laboratory`s ability to homogenize solid core segments.

  13. Risks from Past, Current, and Potential Hanford Single Shell Tank Leaks

    SciTech Connect

    Triplett, Mark B.; Watson, David J.; Wellman, Dawn M.

    2013-05-24

    Due to significant delays in constructing and operating the Waste Treatment Plant, which is needed to support retrieval of waste from Hanford’s single shell tanks (SSTs), SSTs may now be required to store tank waste for two to three more decades into the future. Many SSTs were built almost 70 years ago, and all SSTs are well beyond their design lives. Recent examination of monitoring data suggests several of the tanks, which underwent interim stabilization a decade or more ago, may be leaking small amounts (perhaps 150–300 gallons per year) to the subsurface environment. A potential leak from tank T-111 is estimated to have released approximately 2,000 gallons into the subsurface. Observations of past leak events, recently published simulation results, and new simulations all suggest that recent leaks are unlikely to affect underlying groundwater above regulatory limits. However, these recent observations remind us that much larger source terms are still contained in the tanks and are also present in the vadose zone from historical intentional and unintentional releases. Recently there have been significant improvements in methods for detecting and characterizing soil moisture and contaminant releases, understanding and controlling mass-flux, and remediating deep vadose zone and groundwater plumes. To ensure extended safe storage of tank waste in SSTs, the following actions are recommended: 1) Improve capabilities for intrusion and leak detection. 2) Develop defensible conceptual models of intrusion and leak mechanisms. 3) Apply enhanced subsurface characterization methods to improve detection and quantification of moisture changes beneath tanks. 4) Maintain a flux-based assessment of past, present, and potential tank leaks to assess risks and to maintain priorities for applying mitigation actions. 5) Implement and maintain effective mitigation and remediation actions to protect groundwater resources. These actions will enable limited resources to be applied to

  14. Tank characterization report for single-shell Tank 241-B-110

    SciTech Connect

    Amato, L.C.; De Lorenzo, D.S.; DiCenso, A.T.; Rutherford, J.H.; Stephens, R.H.; Heasler, P.G.; Brown, T.M.; Simpson, B.C.

    1994-08-01

    Single-shell Tank 241-B-110 is an underground storage tank containing radioactive waste. The tank was sampled at various times between August and November of 1989 and later in April of 1990. The analytical data gathered from these sampling efforts were used to generate this Tank Characterization Report. Tank 241-B-110, located in the 200 East Area B Tank Farm, was constructed in 1943 and 1944, and went into service in 1945 by receiving second cycle decontamination waste from the B and T Plants. During the service life of the tank, other wastes were added including B Plant flush waste, B Plant fission product waste, B Plant ion exchange waste, PUREX Plant coating waste, and waste from Tank 241-B-105. The tank currently contains 246,000 gallons of non-complexed waste, existing primarily as sludge. Approximately 22,000 gallons of drainable interstitial liquid and 1,000 gallons of supernate remain. The solid phase of the waste is heterogeneous, for the top layer and subsequent layers have significantly different chemical compositions and are visually distinct. A complete analysis of the top layer has not been done, and auger sampling of the top layer is recommended to fully characterize the waste in Tank 241-B-110. The tank is not classified as a Watch List tank; however, it is a Confirmed Leaker, having lost nearly 10,000 gallons of waste. The waste in Tank 241-B-110 is primarily precipitated salts, some of which are composed of radioactive isotopes. The most prevalent analytes include water, bismuth, iron, nitrate, nitrite, phosphate, silicon, sodium, and sulfate. The major radionuclide constituents are {sup 137}Cs and {sup 90}Sr.

  15. Sample preparation for semivolatile organics analysis of Hanford single-shell tank waste with high nitrate/nitrite and water content

    SciTech Connect

    Stromatt, R.W.; Hoppe, E.W.; Steele, M.J.

    1993-11-01

    This report describes research work carried out to solve sample preparation problems associated with applying gas chromatography with mass spectrometric detection (GC/MS) to the analysis of single shell tank (SST) samples from Hanford for semivolatile organic compounds. Poor performance was found when applying the procedures based on the U.S. Environmental Protection Agency (EPA), Contract Laboratory Program, Statement of Work (CLP SOW). Analysis work was carried out on simulated drainable liquid modeled after the SST core samples which had evidenced analysis problems. Some work was also conducted on true SST samples. It was found that the pH range was too broad in the original procedure. It was also found that by decreasing the amount of methanol used in the extraction process, problems associated with the formation of an azeotrope phase could be avoided. The authors suggest a new procedure, whose eventual application to a wide array of SST samples will lend itself to better quality control limits.

  16. One- and two-dimensional modeling of argon K-shell emission from gas-puff Z-pinch plasmas

    NASA Astrophysics Data System (ADS)

    Thornhill, J. W.; Chong, Y. K.; Apruzese, J. P.; Davis, J.; Clark, R. W.; Giuliani, J. L.; Terry, R. E.; Velikovich, A. L.; Commisso, R. J.; Whitney, K. G.; Frese, M. H.; Frese, S. D.; Levine, J. S.; Qi, N.; Sze, H.; Failor, B. H.; Banister, J. W.; Coleman, P. L.; Coverdale, C. A.; Jones, B.; Deeney, C.

    2007-06-01

    In this paper, a theoretical model is described and demonstrated that serves as a useful tool for understanding K-shell radiating Z-pinch plasma behavior. Such understanding requires a self-consistent solution to the complete nonlocal thermodynamic equilibrium kinetics and radiation transport in order to realistically model opacity effects and the high-temperature state of the plasma. For this purpose, we have incorporated into the MACH2 two-dimensional magnetohydrodynamic (MHD) code [R. E. Peterkin et al., J. Comput. Phys. 140, 148 (1998)] an equation of state, called the tabular collisional radiative equilibrium (TCRE) model [J. W. Thornhill et al., Phys. Plasmas 8, 3480 (2001)], that provides reasonable approximations to the plasma's opacity state. MACH2 with TCRE is applied toward analyzing the multidimensional implosion behavior that occurred in Decade Quad (DQ) [D. Price et al., Proceedings of the 12th IEEE Pulsed Power Conference, Monterey, CA, edited by C. Stallings and H. Kirbie (IEEE, New York, 1999), p. 489] argon gas puff experiments that employed a 12cm diameter nozzle with and without a central gas jet on axis. Typical peak drive currents and implosion times in these experiments were ˜6MA and ˜230ns. By using Planar Laser Induced Fluorescence measured initial density profiles as input to the calculations, the effect these profiles have on the ability of the pinch to efficiently produce K-shell emission can be analyzed with this combined radiation-MHD model. The calculated results are in agreement with the experimental result that the DQ central-jet configuration is superior to the no-central-jet experiment in terms of producing more K-shell emission. These theoretical results support the contention that the improved operation of the central-jet nozzle is due to the better suppression of instabilities and the higher-density K-shell radiating conditions that the central-jet configuration promotes. When we applied the model toward projecting argon K-shell

  17. Effective enhancement of gas separation performance in mixed matrix membranes using core/shell structured multi-walled carbon nanotube/graphene oxide nanoribbons

    NASA Astrophysics Data System (ADS)

    Xue, Qingzhong; Pan, Xinglong; Li, Xiaofang; Zhang, Jianqiang; Guo, Qikai

    2017-02-01

    Novel core/shell structured multi-walled carbon nanotube/graphene oxide nanoribbons (MWCNT@GONRs) nanohybrids were successfully prepared using a modified chemical longitudinal unzipping method. Subsequently, the MWCNT@GONRs nanohybrids were used as fillers to enhance the gas separation performance of polyimide based mixed matrix membranes (MMMs). It is found that MMMs concurrently exhibited higher gas selectivity and higher gas permeability compared to pristine polyimide. The high gas selectivity could be attributed to the GONRs shell, which provided a selective barrier and large gas adsorbed area, while the high gas permeability resulted from the hollow structured MWCNTs core with smooth internal surface, which acted as a rapid transport channel. MWCNT@GONRs could be promising candidates to improve gas separation performance of MMMs due to the unique microstructures, ease of synthesis and low filling loading.

  18. Single-step gas phase synthesis of stable iron aluminide nanoparticles with soft magnetic properties

    SciTech Connect

    Vernieres, Jerome Benelmekki, Maria; Kim, Jeong-Hwan; Grammatikopoulos, Panagiotis; Diaz, Rosa E.; Bobo, Jean-François; Sowwan, Mukhles

    2014-11-01

    Soft magnetic alloys at the nanoscale level have long generated a vivid interest as candidate materials for technological and biomedical purposes. Consequently, controlling the structure of bimetallic nanoparticles in order to optimize their magnetic properties, such as high magnetization and low coercivity, can significantly boost their potential for related applications. However, traditional synthesis methods stumble upon the long standing challenge of developing true nanoalloys with effective control over morphology and stability against oxidation. Herein, we report on a single-step approach to the gas phase synthesis of soft magnetic bimetallic iron aluminide nanoparticles, using a versatile co-sputter inert gas condensation technique. This method allowed for precise morphological control of the particles; they consisted of an alloy iron aluminide crystalline core (DO{sub 3} phase) and an alumina shell, which reduced inter-particle interactions and also prevented further oxidation and segregation of the bimetallic core. Remarkably, the as-deposited alloy nanoparticles show interesting soft magnetic properties, in that they combine a high saturation magnetization (170 emu/g) and low coercivity (less than 20 Oe) at room temperature. Additional functionality is tenable by modifying the surface of the particles with a polymer, to ensure their good colloidal dispersion in aqueous environments.

  19. Self assembly, mobilization, and flotation of crude oil contaminated sand particles as granular shells on gas bubbles in water.

    PubMed

    Tansel, Berrin; Boglaienko, Daria

    2017-01-01

    Contaminant fate and transport studies and models include transport mechanisms for colloidal particles and dissolved ions which can be easily moved with water currents. However, mobilization of much larger contaminated granular particles (i.e., sand) in sediments have not been considered as a possible mechanism due to the relatively larger size of sand particles and their high bulk density. We conducted experiments to demonstrate that oil contaminated granular particles (which exhibit hydrophobic characteristics) can attach on gas bubbles to form granular shells and transfer from the sediment phase to the water column. The interactions and conditions necessary for the oil contaminated granular particles to self assemble as tightly packed granular shells on the gas bubbles which transfer from sediment phase to the water column were evaluated both experimentally and theoretically for South Louisiana crude oil and quartz sand particles. Analyses showed that buoyancy forces can be adequate to move the granular shell forming around the air bubbles if the bubble radius is above 0.001mm for the sand particles with 0.28mm diameter. Relatively high magnitude of the Hamaker constant for the oil film between sand and air (5.81×10(-20)J for air-oil-sand) indicates that air bubbles have high affinity to attach on the oil film that is on the sand particles in comparison to attaching to the sand particles without the oil film in water (1.60×10(-20)J for air-water-sand). The mobilization mechanism of the contaminated granular particles with gas bubbles can occur in natural environments resulting in transfer of granular particles from sediments to the water column.

  20. Efficient and accurate local single reference correlation methods for high-spin open-shell molecules using pair natural orbitals

    NASA Astrophysics Data System (ADS)

    Hansen, Andreas; Liakos, Dimitrios G.; Neese, Frank

    2011-12-01

    A production level implementation of the high-spin open-shell (spin unrestricted) single reference coupled pair, quadratic configuration interaction and coupled cluster methods with up to doubly excited determinants in the framework of the local pair natural orbital (LPNO) concept is reported. This work is an extension of the closed-shell LPNO methods developed earlier [F. Neese, F. Wennmohs, and A. Hansen, J. Chem. Phys. 130, 114108 (2009), 10.1063/1.3086717; F. Neese, A. Hansen, and D. G. Liakos, J. Chem. Phys. 131, 064103 (2009), 10.1063/1.3173827]. The internal space is spanned by localized orbitals, while the external space for each electron pair is represented by a truncated PNO expansion. The laborious integral transformation associated with the large number of PNOs becomes feasible through the extensive use of density fitting (resolution of the identity (RI)) techniques. Technical complications arising for the open-shell case and the use of quasi-restricted orbitals for the construction of the reference determinant are discussed in detail. As in the closed-shell case, only three cutoff parameters control the average number of PNOs per electron pair, the size of the significant pair list, and the number of contributing auxiliary basis functions per PNO. The chosen threshold default values ensure robustness and the results of the parent canonical methods are reproduced to high accuracy. Comprehensive numerical tests on absolute and relative energies as well as timings consistently show that the outstanding performance of the LPNO methods carries over to the open-shell case with minor modifications. Finally, hyperfine couplings calculated with the variational LPNO-CEPA/1 method, for which a well-defined expectation value type density exists, indicate the great potential of the LPNO approach for the efficient calculation of molecular properties.

  1. Coupled cluster calculation for ground state properties of closed-shell nuclei and single hole states.

    NASA Astrophysics Data System (ADS)

    Mihaila, Bogdan; Heisenberg, Jochen

    2000-04-01

    We continue the investigations of ground state properties of closed-shell nuclei using the Argonne v18 realistic NN potential, together with the Urbana IX three-nucleon interaction. The ground state wave function is used to calculate the charge form factor and charge density. Starting with the ground state wave function of the closed-shell nucleus, we use the equation of motion technique to calculate the ground state and excited states of a neighboring nucleus. We then generate the corresponding magnetic form factor. We correct for distortions due to the interaction between the electron probe and the nuclear Coulomb field using the DWBA picture. We compare our results with the available experimental data. Even though our presentation will focus mainly on the ^16O and ^15N nuclei, results for other nuclei in the p and s-d shell will also be presented.

  2. Physical and Liquid Chemical Simulant Formulations for Transuranic Waste in Hanford Single-Shell Tanks

    SciTech Connect

    Rassat, Scot D.; Bagaasen, Larry M.; Mahoney, Lenna A.; Russell, Renee L.; Caldwell, Dustin D.; Mendoza, Donaldo P.

    2003-07-30

    CH2M HILL Hanford Group, Inc. (CH2M HILL) is in the process of identifying and developing supplemental process technologies to accelerate the tank waste cleanup mission. A range of technologies is being evaluated to allow disposal of Hanford waste types, including transuranic (TRU) process wastes. Ten Hanford single-shell tanks (SSTs) have been identified whose contents may meet the criteria for designation as TRU waste: the B-200 series (241-B-201, -B-202, -B 203, and B 204), the T-200 series (241-T-201, T 202, -T-203, and -T-204), and Tanks 241-T-110 and -T-111. CH2M HILL has requested vendor proposals to develop a system to transfer and package the contact-handled TRU (CH-TRU) waste retrieved from the SSTs for subsequent disposal at the Waste Isolation Pilot Plant (WIPP). Current plans call for a modified ''dry'' retrieval process in which a liquid stream is used to help mobilize the waste for retrieval and transfer through lines and vessels. This retrieval approach requires that a significant portion of the liquid be removed from the mobilized waste sludge in a ''dewatering'' process such as centrifugation prior to transferring to waste packages in a form suitable for acceptance at WIPP. In support of CH2M HILL's effort to procure a TRU waste handling and packaging process, Pacific Northwest National Laboratory (PNNL) developed waste simulant formulations to be used in evaluating the vendor's system. For the SST CH-TRU wastes, the suite of simulants includes (1) nonradioactive chemical simulants of the liquid fraction of the waste, (2) physical simulants that reproduce the important dewatering properties of the waste, and (3) physical simulants that can be used to mimic important rheological properties of the waste at different points in the TRU waste handling and packaging process. To validate the simulant formulations, their measured properties were compared with the limited data for actual TRU waste samples. PNNL developed the final simulant formulations

  3. Tank characterization report for single-shell tank 241-C-110. Revision 1

    SciTech Connect

    Benar, C.J.

    1997-06-14

    One of the major functions of the Tank Waste Remediation System (IWRS) is to characterize wastes in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis, along with other available information about a tank, are compiled and maintained in a tank characterization report (TCR). This report and its appendixes serve as the TCR for single-shell tank 241-C-110. The objectives of this report are to use characterization data in response to technical issues associated with 241-C-110 waste and to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Supporting data and information are contained in the appendixes. This report also supports the requirements of the Hanford Federal Facility Agreement and Consent Order milestone M-44-05. Characterization information presented in this report originated from sample analyses and known historical sources. While only the results from recent sample events will be used to fulfill the requirements of the data quality objectives (DQOs), other information can be used to support or question conclusions derived from these results. Historical information for tank 241-C-110 are provided included surveillance information, records pertaining to waste transfers and tank operations, and1124 expected tank contents derived from a process knowledge model. The sampling events are listed, as well as sample data obtained before 1989. The results of the 1992 sampling events are also reported in the data package. The statistical analysis and numerical manipulation of data used in issue resolution are reported in Appendix C. Appendix D contains the evaluation to establish the best basis for the inventory estimate and the statistical analysis performed for this evaluation. A bibliography that resulted from an in-depth literature search of all known information sources applicable to tank 241-C-110 and its respective waste types is contained in Appendix E

  4. Development and Deployment of the Extended Reach Sluicing System (ERSS) for Retrieval of Hanford Single Shell Tank Waste. Draft

    SciTech Connect

    Bauer, Roger E.; Figley, Reed R.; Innes, A. G.

    2013-11-11

    A history of the evolution and the design development of Extended Reach Sluicer System (ERSS) is presented. Several challenges are described that had to be overcome to create a machine that went beyond the capabilities of prior generation sluicers to mobilize waste in Single Shell Tanks for pumping into Double Shell Tank receiver tanks. Off-the-shelf technology and traditional hydraulic fluid power systems were combined with the custom-engineered components to create the additional functionality of the ERSS, while still enabling it to fit within very tight entry envelope into the SST. Problems and challenges inevitably were encountered and overcome in ways that enhance the state of the art of fluid power applications in such constrained environments. Future enhancements to the ERSS design are explored for retrieval of tanks with different dimensions and internal obstacles.

  5. Rapid induction of dopamine sensitization in the nucleus accumbens shell induced by a single injection of cocaine.

    PubMed

    Singer, Bryan F; Bryan, Myranda A; Popov, Pavlo; Robinson, Terry E; Aragona, Brandon J

    2017-05-01

    Repeated intermittent exposure to cocaine results in the neurochemical sensitization of dopamine (DA) transmission within the nucleus accumbens (NAc). Indeed, the excitability of DA neurons in the ventral tegmental area (VTA) is enhanced within hours of initial psychostimulant exposure. However, it is not known if this is accompanied by a comparably rapid change in the ability of cocaine to increase extracellular DA concentrations in the ventral striatum. To address this question we used fast-scan cyclic voltammetry (FSCV) in awake-behaving rats to measure DA responses in the NAc shell following an initial intravenous cocaine injection, and then again 2-h later. Both injections quickly elevated DA levels in the NAc shell, but the second cocaine infusion produced a greater effect than the first, indicating sensitization. This suggests that a single injection of cocaine induces sensitization-related plasticity very rapidly within the mesolimbic DA system.

  6. Study on the DFB fiber laser accelerometer with a metal-shell-packaged single-cylinder mandrel structure

    NASA Astrophysics Data System (ADS)

    Li, Haitao; Ma, Lina; Yang, Huayong; Luo, Hong

    2014-12-01

    To realize the miniature of fiber laser accelerometers, a metal-shell-packaged single-cylinder mandrel-structured distributed feedback (DFB) fiber laser accelerometer was proposed, whose key sensing component is the DFB fiber laser with a cavity length of 16mm. Simulation results show that when the weight of the mass is 400g, the radius of the thin shell cylinder is 0.5cm, we will find that the resonance frequency of the sensor is 900Hz and its sensitivity reaches 18.1pm/g. It is also shown that its sensitivity achieved 42.8dB.re.rad/g while demodulated by an unbalanced Michelson optical fiber interferometer with 1m path difference. In addition, the effects of its structure and material parameters on the acceleration sensitivity are also studied.

  7. Preliminary tank characterization report for single-shell tank 241-B-105: best-basis inventory

    SciTech Connect

    Higley, B.A.

    1997-07-01

    An effort is underway to provide waste inventory estimates that will serve as standard characterization source terms for the @various waste management activities. As part of this effort, an evaluation of available information for singlb-shell tank 241-B-105 was performed, and a best-basis inventory was established. This work follows the methodology that was established by the standard inventory task.

  8. In situ rheology and gas volume in Hanford double-shell waste tanks

    SciTech Connect

    Stewart, C.W.; Alzheimer, J.M.; Brewster, M.E.; Chen, G.; Reid, H.C.; Shepard, C.L.; Terrones, G.; Mendoza, R.E.

    1996-09-01

    This report is a detailed characterization of gas retention and release in 6 Hanford DS waste tanks. The results came from the ball rheometer and void fraction instrument in (flammable gas watch list) tanks SY-101, SY-103, AW-101, AN-103, AN-104, and AN-105 are presented. Instrument operation and derivation of data reduction methods are presented. Gas retention and release information is summarized for each tank and includes tank fill history and instrumentation, waste configuration, gas release, void fraction distribution, gas volumes, rheology, and photographs of the waste column from extruded core samples. Potential peak burn pressure is computed as a function of gas release fraction to portray the `hazard signature` of each tank. It is shown that two tanks remain well below the maximum allowable pressure, even if the entire gas content were released and ignited, and that none of the others present a hazard with their present gas release behavior.

  9. Size and medium conductivity dependence on dielectrophoretic behaviors of gas core poly-L-lysine shell nanoparticles.

    PubMed

    Yang, Chungja; Wu, Chun-Jen; Ostafin, Agnes E; Thibaudeau, Giselle; Minerick, Adrienne R

    2015-04-01

    Dynamic (dis)assembly of biocompatible nanoparticles into 3D, packed structures would benefit drug delivery, films, and diagnostics. Dielectrophoretic (DEP) microdevices can rapidly assemble and manipulate polarizable particles within nonuniform electric fields. DEP has primarily discerned micrometer particles since nanoparticles experience smaller forces. This work examines conductivity and size DEP dependencies of previously unexplored spherical core-shell nanoparticle (CSnp) into 3D particle assemblies. Poly-L-lysine shell material was custom synthesized around a gas core to form CSnps. DEP frequencies from 1 kHz to 80 MHz at fixed 5 volts peak-to-peak and medium conductivities of 10(-5) and 10(-3) S/m were tested. DEP responses of ∼220 and ∼400 nm poly-L-lysine CSnps were quantified via video intensity densitometry at the microdevice's quadrapole electrode center for negative DEP (nDEP) and adjacent to electrodes for positive DEP. Intensity densitometry was then translated into a relative DEP response curve. An unusual nDEP peak occurred at ∼57 MHz with 25-80 times greater apparent nDEP force. All electrical circuit components were then impedance matched, which changed the observed response to weak positive DEP at low frequencies and consistently weak nDEP from ∼100 kHz to 80 MHz. This impedance-matched behavior agrees with conventional Clausius-Mossotti DEP signatures taking into account the gas core's contributions to the polarization mechanisms. This work describes a potential pitfall when conducting DEP at higher frequencies in microdevices and concurrently demonstrates nDEP behavior for a chemically and structurally distinct particle system. This work provides insight into organic shell material properties in nanostructures and strategies to facilitate dynamic nanoparticle assemblies.

  10. A single-walled carbon nanotube network gas sensing device.

    PubMed

    Wang, Li-Chun; Tang, Kea-Tiong; Teng, I-Ju; Kuo, Cheng-Tzu; Ho, Cheng-Long; Kuo, Han-Wen; Su, Tseng-Hsiung; Yang, Shang-Ren; Shi, Gia-Nan; Chang, Chang-Ping

    2011-01-01

    The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT) networks. The SWCNT networks are synthesized on Al(2)O(3)-deposted SiO(2)/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD). The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO(2) and NH(3) vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO(2) and 24 ppm for NH(3).

  11. A Single-Walled Carbon Nanotube Network Gas Sensing Device

    PubMed Central

    Wang, Li-Chun; Tang, Kea-Tiong; Teng, I-Ju; Kuo, Cheng-Tzu; Ho, Cheng-Long; Kuo, Han-Wen; Su, Tseng-Hsiung; Yang, Shang-Ren; Shi, Gia-Nan; Chang, Chang-Ping

    2011-01-01

    The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT) networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD). The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3. PMID:22164044

  12. Optical heating and temperature determination of core-shell gold nanoparticles and single-walled carbon nanotube microparticles.

    PubMed

    Yashchenok, Alexey; Masic, Admir; Gorin, Dmitry; Inozemtseva, Olga; Shim, Bong Sup; Kotov, Nicholas; Skirtach, Andre; Möhwald, Helmuth

    2015-03-18

    The real-time temperature measurement of nanostructured materials is particularly attractive in view of increasing needs of local temperature probing with high sensitivity and resolution in nanoelectronics, integrated photonics, and biomedicine. Light-induced heating and Raman scattering of single-walled carbon nanotubes with adsorbed gold nanoparticles decorating silica microparticles are reported, by both green and near IR lasers. The plasmonic shell is used as nanoheater, while the single-walled carbon nanotubes are Raman active and serve as a thermometer. Stokes and Anti-Stokes Raman spectra of single-walled carbon nanotubes serve to estimate the effective light-induced temperature rise on the metal nanoparticles. The temperature rise is constant with time, indicating stability of the adsorption density. The effective temperatures derived from Stokes and Anti-Stokes intensities are correlated with those measured in a heating stage. The resolution of the thermal experiments in our study was found to be 5-40 K.

  13. Tailoring surface plasmon resonance and dipole cavity plasmon modes of scattering cross section spectra on the single solid-gold/gold-shell nanorod

    NASA Astrophysics Data System (ADS)

    Chou Chau, Yuan-Fong; Lim, Chee Ming; Lee, Chuanyo; Huang, Hung Ji; Lin, Chun-Ting; Kumara, N. T. R. N.; Yoong, Voo Nyuk; Chiang, Hai-Pang

    2016-09-01

    Tunable surface plasmon resonance (SPR) and dipole cavity plasmon modes of the scattering cross section (SCS) spectra on the single solid-gold/gold-shell nanorod have been numerically investigated by using the finite element method. Various effects, such as the influence of SCS spectra under x- and y-polarizations on the surface of the single solid-gold/gold-shell nanorod, are discussed in detail. With the single gold-shell nanorod, one can independently tune the relative SCS spectrum width by controlling the rod length and rod diameter, and the surface scattering by varying the shell thickness and polarization direction, as well as the dipole peak energy. These behaviors are consistent with the properties of localized SPRs and offer a way to optically control and produce selected emission wavelengths from the single solid-gold/gold-shell nanorod. The electric field and magnetic distributions provide us a qualitative idea of the geometrical properties of the single solid-gold/gold-shell nanorod on plasmon resonance.

  14. Statistical analysis of entropy generation in longitudinally finned tube heat exchanger with shell side nanofluid by a single phase approach

    NASA Astrophysics Data System (ADS)

    Konchada, Pavan Kumar; Pv, Vinay; Bhemuni, Varaprasad

    2016-06-01

    The presence of nanoparticles in heat exchangers ascertained increment in heat transfer. The present work focuses on heat transfer in a longitudinal finned tube heat exchanger. Experimentation is done on longitudinal finned tube heat exchanger with pure water as working fluid and the outcome is compared numerically using computational fluid dynamics (CFD) package based on finite volume method for different flow rates. Further 0.8% volume fraction of aluminum oxide (Al2O3) nanofluid is considered on shell side. The simulated nanofluid analysis has been carried out using single phase approach in CFD by updating the user-defined functions and expressions with thermophysical properties of the selected nanofluid. These results are thereafter compared against the results obtained for pure water as shell side fluid. Entropy generated due to heat transfer and fluid flow is calculated for the nanofluid. Analysis of entropy generation is carried out using the Taguchi technique. Analysis of variance (ANOVA) results show that the inlet temperature on shell side has more pronounced effect on entropy generation.

  15. The Influence of Geometrical Parameters on the Buckling Behavior of Conical Shell by the Single Perturbation Load Approach

    NASA Astrophysics Data System (ADS)

    Di Pasqua, Maria Francesca; Khakimova, Regina; Castro, Saullo G. P.; Arbelo, Mariano A.; Riccio, Aniello; Degenhardt, Richard

    2015-08-01

    Since the development of the first theories to predict the buckling induced by axial compression in shells sensitive to imperfections, a significant discrepancy between theoretical and experimental results has been observed. Donnell and Koiter are among the first authors demonstrating, for these structures, the relevant influence of the geometrical imperfections on the reduction of the buckling load. Currently, the preliminary design of imperfections sensitive shell structures used in space applications is carried out according to the NASA SP-8007guideline. However, several studies have proven that this guideline leads to over-conservative design configurations when considering the geometrical and material imperfections existing in real cones. Since the pioneer work of Arbocz, alternative methods have been investigated to overcome this issue. Among the different approaches, in this paper, the Single Perturbation Load Approach (SPLA), originally developed byHühne as a deterministic way to calculate the knock-down factor of imperfection sensitive shells, is further studied. Indeed, a numerical investigation about the application of the SPLA to the simulation of the mechanical behavior of imperfection sensitive composite conical structures under axial compression is presented. This study is related to part of the work performed in the frame of the European Union (EU) project DESICOS.

  16. 2D Radiation MHD K-shell Modeling of Single Wire Array Stainless Steel Experiments on the Z Machine

    SciTech Connect

    Thornhill, J. W.; Giuliani, J. L.; Apruzese, J. P.; Chong, Y. K.; Davis, J.; Dasgupta, A.; Whitney, K. G.; Clark, R. W.; Jones, B.; Coverdale, C. A.; Ampleford, D. J.; Cuneo, M. E.; Deeney, C.

    2009-01-21

    Many physical effects can produce unstable plasma behavior that affect K-shell emission from arrays. Such effects include: asymmetry in the initial density profile, asymmetry in power flow, thermal conduction at the boundaries, and non-uniform wire ablation. Here we consider how asymmetry in the radiation field also contributes to the generation of multidimensional plasma behavior that affects K-shell power and yield. To model this radiation asymmetry, we have incorporated into the MACH2 r-z MHD code a self-consistent calculation of the non-LTE population kinetics based on radiation transport using multi-dimensional ray tracing. Such methodology is necessary for modeling the enhanced radiative cooling that occurs at the anode and cathode ends of the pinch during the run-in phase of the implosion. This enhanced radiative cooling is due to reduced optical depth at these locations producing an asymmetric flow of radiative energy that leads to substantial disruption of large initial diameter (>5 cm) pinches and drives 1D into 2D fluid (i.e., Rayleigh-Taylor like) flows. The impact of this 2D behavior on K-shell power and yield is investigated by comparing 1D and 2D model results with data obtained from a series of single wire array stainless steel experiments performed on the Z generator.

  17. X-ray Bragg Ptychography on a Single InGaN/GaN Core-Shell Nanowire.

    PubMed

    Dzhigaev, Dmitry; Stankevič, Tomaš; Bi, Zhaoxia; Lazarev, Sergey; Rose, Max; Shabalin, Anatoly; Reinhardt, Juliane; Mikkelsen, Anders; Samuelson, Lars; Falkenberg, Gerald; Feidenhans'l, Robert; Vartanyants, Ivan A

    2017-03-20

    The future of solid-state lighting can be potentially driven by applications of InGaN/GaN core-shell nanowires. These heterostructures provide the possibility for fine-tuning of functional properties by controlling a strain state between mismatched layers. We present a nondestructive study of a single 400 nm-thick InGaN/GaN core-shell nanowire using two-dimensional (2D) X-ray Bragg ptychography (XBP) with a nanofocused X-ray beam. The XBP reconstruction enabled the determination of a detailed three-dimensional (3D) distribution of the strain in the particular nanowire using a model based on finite element method. We observed the strain induced by the lattice mismatch between the GaN core and InGaN shell to be in the range from -0.1% to 0.15% for an In concentration of 30%. The maximum value of the strain component normal to the facets was concentrated at the transition region between the main part of the nanowire and the GaN tip. In addition, a variation in misfit strain relaxation between the axial growth and in-plane directions was revealed.

  18. Effect of the core/shell interface on auger recombination evaluated by single-quantum-dot spectroscopy.

    PubMed

    Park, Young-Shin; Bae, Wan Ki; Padilha, Lazaro A; Pietryga, Jeffrey M; Klimov, Victor I

    2014-02-12

    Previous single-particle spectroscopic studies of colloidal quantum dots have indicated a significant spread in biexciton lifetimes across an ensemble of nominally identical nanocrystals. It has been speculated that in addition to dot-to-dot variation in physical dimensions, this spread is contributed to by variations in the structure of the quantum dot interface, which controls the shape of the confinement potential. Here, we directly evaluate the effect of the composition of the core-shell interface on single- and multiexciton dynamics via side-by-side measurements of individual core-shell CdSe/CdS nanocrystals with a sharp versus smooth (graded) interface. To realize the latter type of structures we incorporate a CdSexS1-x alloy layer of controlled composition and thickness between the CdSe core and the CdS shell. We observe that while having essentially no effect on single-exciton decay, the interfacial alloy layer leads to a systematic increase in biexciton lifetimes, which correlates with the increase in the biexciton emission efficiency, as inferred from two-photon correlation measurements. These observations provide direct experimental evidence that in addition to the size of the quantum dot, its interfacial properties also significantly affect the rate of Auger recombination, which governs biexciton decay. These findings help rationalize previous observations of a significant heterogeneity in the biexciton lifetimes across similarly sized quantum dots and should facilitate the development of "Auger-recombination-free" colloidal nanostructures for a range of applications from lasers and light-emitting diodes to photodetectors and solar cells.

  19. Measurement and simulation of anisotropic magnetoresistance in single GaAs/MnAs core/shell nanowires

    NASA Astrophysics Data System (ADS)

    Liang, J.; Wang, J.; Paul, A.; Cooley, B. J.; Rench, D. W.; Dellas, N. S.; Mohney, S. E.; Engel-Herbert, R.; Samarth, N.

    2012-04-01

    We report four probe measurements of the low field magnetoresistance (MR) in single core/shell GaAs/MnAs nanowires (NWs) synthesized by molecular beam epitaxy, demonstrating clear signatures of anisotropic magnetoresistance that track the field-dependent magnetization. A comparison with micromagnetic simulations reveals that the principal characteristics of the magnetoresistance data can be unambiguously attributed to the nanowire segments with a zinc blende GaAs core. The direct correlation between magnetoresistance, magnetization, and crystal structure provides a powerful means of characterizing individual hybrid ferromagnet/semiconductor nanostructures.

  20. Single and multi-layered core-shell structures based on ZnO nanorods obtained by aerosol assisted chemical vapor deposition

    SciTech Connect

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Miki-Yoshida, M.

    2015-07-15

    Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-layered shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition

  1. Tank characterization report for single-shell tank 241-BY-104

    SciTech Connect

    Benar, C.J.

    1996-09-26

    This characterization report summarizes the available information on the historical uses, current status, and the sampling and analysis results of waste contained in underground storage tank 241-BY-104. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order, Milestone M-44-09. Tank 241-BY-104 is one of 12 single-shell tanks located in the BY-Tank Farm in the 200 East Area of the Hanford Site. Tank 241-BY-104 entered service in the first quarter of 1950 with a transfer of metal waste from an unknown source. Through cascading, the tank was full of metal waste by the second quarter of 1951. The waste was sluiced in the second quarter of 1954. Uranium recovery (tributyl phosphate) waste was sent from tank 241-BY-107 during the second quarter of 1955 and from tank 241-BY-110 during the third quarter of 1955. Most of this waste was sent to a crib during the fourth quarter of 1955. During the third and fourth quarters of 1956 and the second and third quarters of 1957, the tank received waste from the in-plant ferrocyanide scavenging process (PFeCN2) from tanks 241-BY-106, -107, -108, and -110. This waste type is predicted to compose the bottom layer of waste currently in the tank. The tank received PUREX cladding waste (CWP) periodically from 1961 to 1968. Ion-exchange waste from cesium recovery operations was received from tank 241-BX-104 during the second and third quarters of 1968. Tank 241-BY-104 received evaporator bottoms waste from the in-tank solidification process that was conducted in the BY-Tank Farm 0247from tanks 241 -BY- 109 and 241 -BY- 1 12 from 1970 to 1974. The upper portion of tank waste is predicted to be composed of BY saltcake. Tank 241-BY-104 was declared inactive in 1977. Waste was saltwell pumped from the tank during the third quarter of 1982 and the fourth quarter of 1985. Table ES-1 and Figure ES-1 describe tank 241-BY-104 and its status. The tank has an operating capacity of 2,869 kL and presently

  2. Single-Shell Tanks Leak Integrity Elements/ SX Farm Leak Causes and Locations - 12127

    SciTech Connect

    Girardot, Crystal; Harlow, Don; Venetz, Theodore; Washenfelder, Dennis; Johnson, Jeremy

    2012-07-01

    Washington River Protection Solutions, LLC (WRPS) developed an enhanced single-shell tank (SST) integrity project in 2009. An expert panel on SST integrity was created to provide recommendations supporting the development of the project. One primary recommendation was to expand the leak assessment reports (substitute report or LD-1) to include leak causes and locations. The recommendation has been included in the M-045-91F Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) as one of four targets relating to SST leak integrity. The 241-SX Farm (SX Farm) tanks with leak losses were addressed on an individual tank basis as part of LD-1. Currently, 8 out of 23 SSTs that have been reported to having a liner leak are located in SX Farm. This percentage was the highest compared to other tank farms which is why SX Farm was analyzed first. The SX Farm is comprised of fifteen SSTs built 1953-1954. The tanks are arranged in rows of three tanks each, forming a cascade. Each of the SX Farm tanks has a nominal 1-million-gal storage capacity. Of the fifteen tanks in SX Farm, an assessment reported leak losses for the following tanks: 241-SX-107, 241-SX-108, 241-SX-109, 241-SX- 111, 241-SX-112, 241-SX-113, 241-SX-114 and 241-SX-115. The method used to identify leak location consisted of reviewing in-tank and ex-tank leak detection information. This provided the basic data identifying where and when the first leaks were detected. In-tank leak detection consisted of liquid level measurement that can be augmented with photographs which can provide an indication of the vertical leak location on the sidewall. Ex-tank leak detection for the leaking tanks consisted of soil radiation data from laterals and dry-wells near the tank. The in-tank and ex-tank leak detection can provide an indication of the possible leak location radially around and under the tank. Potential leak causes were determined using in-tank and ex-tank information that is not directly related to

  3. SINGLE-SHELL TANKS LEAK INTEGRITY ELEMENTS/SX FARM LEAK CAUSES AND LOCATIONS - 12127

    SciTech Connect

    VENETZ TJ; WASHENFELDER D; JOHNSON J; GIRARDOT C

    2012-01-25

    Washington River Protection Solutions, LLC (WRPS) developed an enhanced single-shell tank (SST) integrity project in 2009. An expert panel on SST integrity was created to provide recommendations supporting the development of the project. One primary recommendation was to expand the leak assessment reports (substitute report or LD-1) to include leak causes and locations. The recommendation has been included in the M-045-9IF Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) as one of four targets relating to SST leak integrity. The 241-SX Farm (SX Farm) tanks with leak losses were addressed on an individual tank basis as part of LD-1. Currently, 8 out of 23 SSTs that have been reported to having a liner leak are located in SX Farm. This percentage was the highest compared to other tank farms which is why SX Farm was analyzed first. The SX Farm is comprised of fifteen SSTs built 1953-1954. The tanks are arranged in rows of three tanks each, forming a cascade. Each of the SX Farm tanks has a nominal I-million-gal storage capacity. Of the fifteen tanks in SX Farm, an assessment reported leak losses for the following tanks: 241-SX-107, 241-SX-108, 241-SX-109, 241-SX-111, 241-SX-112, 241-SX-113, 241-SX-114 and 241-SX-115. The method used to identify leak location consisted of reviewing in-tank and ex-tank leak detection information. This provided the basic data identifying where and when the first leaks were detected. In-tank leak detection consisted of liquid level measurement that can be augmented with photographs which can provide an indication of the vertical leak location on the sidewall. Ex-tank leak detection for the leaking tanks consisted of soil radiation data from laterals and drywells near the tank. The in-tank and ex-tank leak detection can provide an indication of the possible leak location radially around and under the tank. Potential leak causes were determined using in-tank and ex-tank information that is not directly related to

  4. Precision polyimide single surface thin film shell apertures and active boundary control

    NASA Astrophysics Data System (ADS)

    Flint, Eric M.; Lindler, Jason E.; Hall, Jonathan L.; Rankine, Charles; Reggelbrugge, Mark

    2006-06-01

    This paper discusses the current status of self supporting precision membrane optical shell technology (MOST) apertures based on thin (25 to 125 um thick) polyimide and polyester films primary shell. Optically relevant doubly curved reflective apertures are realized by inducing permanent curvature into thin substrates that can then be coated. The initial thin nature provides both very low areal density (20 to 200 grams/m2) and compatibility with compact roll stowage. The induced curvature/depth provides the ability to support the shell around the periphery at discrete locations and considerable structural and dynamic stiffness. The discrete mounts also provide an excellent location with which to improve the surface figure and to reject environmental and host structure induced errors. Material microroughness on the leading substrate/coating combination has been measured to down to 3 nm rms over small (100x100um's) sample sizes with white light interferometry. A variety of reflective coated substrates have also been shown to have sub micron rms surface roughness over up to 100mm diameter test apertures using interferometric measurements. Best materials currently have 20nm rms surface roughness noise floors at these sizes. The ability to fabricate shells over a range of prescriptions (R/0.9 to R/2.2) and a range of sizes (0.1 to 0.75m diameter) has been demonstrated. Global surface figure accuracies of 2 to 4 microns rms have been demonstrated at the 0.2m size, and further improvements are anticipated through ongoing improved fabrication techniques (preliminary results indicate sub-micron rms values). The ability of discrete boundary control to improve the shape and maintain it in the face of disturbances (gravity for example) is demonstrated as is the ability to implement high amplitude (multi-wave) Zernike mode surface figure control. Results extending boundary control to interferometric optical level are also presented.

  5. Glass shell manufacturing in space

    NASA Technical Reports Server (NTRS)

    Downs, R. L.; Ebner, M. A.; Nolen, R. L., Jr.

    1981-01-01

    Highly-uniform, hollow glass spheres (shells), which are used for inertial confinement fusion targets, were formed from metal-organic gel powder feedstock in a vertical furnace. As a result of the rapid pyrolysis caused by the furnace, the gel is transformed to a shell in five distinct stages: (a) surface closure of the porous gel; (b) generation of a closed-cell foam structure in the gel; (c) spheridization of the gel and further expansion of the foam; (d) coalescence of the closed-cell foam to a single-void shell; and (e) fining of the glass shell. The heat transfer from the furnace to the falling gel particle was modeled to determine the effective heating rate of the gel. The model predicts the temperature history for a particle as a function of mass, dimensions, specific heat, and absorptance as well as furnace temperature profile and thermal conductivity of the furnace gas. A model was developed that predicts the gravity-induced degradation of shell concentricity in falling molten shells as a function of shell characteristics and time.

  6. A fusion of the closed-shell coupled cluster singles and doubles method and valence-bond theory for bond breaking.

    PubMed

    Small, David W; Head-Gordon, Martin

    2012-09-21

    Closed-shell coupled cluster singles and doubles (CCSD) is among the most important of electronic-structure methods. However, it fails qualitatively when applied to molecular systems with more than two strongly correlated electrons, such as those with stretched or broken covalent bonds. We show that it is possible to modify the doubles amplitudes to obtain a closed-shell CCSD method that retains the computational cost and desirable features of standard closed-shell CCSD, e.g., correct spin symmetry, size extensivity, orbital invariance, etc., but produces greatly improved energies upon bond dissociation of multiple electron pairs; indeed, under certain conditions the dissociation energies are exact.

  7. Fluorescence signals of core-shell quantum dots enhanced by single crystalline gold caps on silicon nanowires

    NASA Astrophysics Data System (ADS)

    Christiansen, S. H.; Chou, J. W.; Becker, M.; Sivakov, V.; Ehrhold, K.; Berger, A.; Chou, W. C.; Chuu, D. S.; Gösele, U.

    2009-04-01

    We use nanoscale (20-300 nm in diameter) single crystalline gold (Au)-caps on silicon nanowires (NWs) grown by the vapor-liquid-solid (VLS) growth mechanism to enhance the fluorescence photoluminescence (PL) signals of highly dilute core/shell CdSeTe/ZnS quantum dots (QDs) in aqueous solution (10-5 M). For NWs without Au-caps, as they appear, for example, after Au etching in aqua regia or buffered KI/I2-solution, essentially no fluorescence signal of the same diluted QDs could be observed. Fluorescence PL signals were measured using excitation with a laser wavelength of 633 nm. The signal enhancement by single crystalline, nanoscale Au-caps is discussed and interpreted based on finite element modeling (FEM).

  8. Methanogenic calcite, 13C-depleted bivalve shells, and gas hydrate from a mud volcano offshore southern California

    USGS Publications Warehouse

    Hein, J.R.; Normark, W.R.; McIntyre, B.R.; Lorenson, T.D.; Powell, C.L.

    2006-01-01

    Methane and hydrogen sulfide vent from a cold seep above a shallowly buried methane hydrate in a mud volcano located 24 km offshore southern California in?? 800 m of water. Bivalves, authigenic calcite, and methane hydrate were recovered in a 2.1 m piston core. Aragonite shells of two bivalve species are unusually depleted in 13C (to -91??? ??13C), the most 13C-depleted shells of marine macrofauna yet discovered. Carbon isotopes for both living and dead specimens indicate that they used, in part, carbon derived from anaerobically oxidized methane to construct their shells. The ??13C values are highly variable, but most are within the range -12??? to -91???. This variability may be diagnostic for identifying cold-seep-hydrate systems in the geologic record. Authigenic calcite is abundant in the cores down to ???1.5 m subbottom, the top of the methane hydrate. The calcite is depleted in 13C (??13C = -46??? to -58???), indicating that carbon produced by anaerobically oxidized methane is the main source of the calcite. Methane sources include a geologic hydrocarbon reservoir from Miocene source rocks, and biogenic and thermogenic degradation of organic matter in basin sediments. Oxygen isotopes indicate that most calcite formed out of isotopic equilibrium with ambient bottom water, under the influence of gas hydrate dissociation and strong methane flux. High metal content in the mud volcano sediment indicates leaching of basement rocks by fluid circulating along an underlying fault, which also allows for a high flux of fossil methane. ?? 2006 Geological Society of America.

  9. Pushered single shell capsule design for the study of high Z mix on the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Sacks, Ryan; Baker, Kevin; Casey, Daniel; Dewald, Edward; Graziani, Frank; MacLaren, Stephan; Nikroo, Abass; Pino, Jesse; Ralph, Joseph; Remington, Bruce; Salmonson, Jay; Smalyuk, Vladimir; Tipton, Robert

    2016-10-01

    Alternative ignition scenarios on the NIF such as double shells require an understanding of the mix between high-Z capsule shell and DT gas. By utilizing the two-shock platform, which has been shown to be a robust, symmetric, and near 1-D implosion, a new design is developed to explore high Z mix. Through the addition of a Ge doped pusher layer on the inner surface of the capsule, mixing of non-fully ionized material can be measured using x-ray emission, nuclear yield diagnostics developed during the CD mix experiments, and characterization of the central core. Using the two-shock design allows for the results to be separated from possible implosion asymmetries, allowing differences in performance between capsules with and without Ge to be attributed to high Z material mixing. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344, Lawrence Livermore National Security, LLC. IM number LLNL-ABS-697758.

  10. Growth and photoluminescence of self-catalyzed GaP/GaNP core/shell nanowires on Si(111) by gas source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Kuang, Y. J.; Sukrittanon, S.; Li, H.; Tu, C. W.

    2012-01-01

    We report a study on self-catalyzed GaP/GaNP core/shell nanowires (NWs) grown on Si(111) by gas-source molecular beam epitaxy. Scanning electron microscopy images show that vertical and uniform GaP NWs and GaP/GaNP core/shell NWs are grown on Si(111). The density ranges from ˜1 × 107 to ˜5 × 108 cm-2 across the substrate. Typical diameters are ˜110 nm for GaP NWs and ˜220 nm for GaP/GaNP NWs. Room temperature photoluminescence (PL) signal from the GaP/GaNP core/shell NWs confirms that N is incorporated in the shell and the average N content is ˜0.9%. The PL low-energy tail is significantly reduced, compared to bulk GaNP.

  11. Employing a cylindrical single crystal in gas-surface dynamics.

    PubMed

    Hahn, Christine; Shan, Junjun; Liu, Ying; Berg, Otto; Kleijn, Aart W; Juurlink, Ludo B F

    2012-03-21

    We describe the use of a polished, hollow cylindrical nickel single crystal to study effects of step edges on adsorption and desorption of gas phase molecules. The crystal is held in an ultra-high vacuum apparatus by a crystal holder that provides axial rotation about a [100] direction, and a crystal temperature range of 89 to 1100 K. A microchannel plate-based low energy electron diffraction/retarding field Auger electron spectrometer (AES) apparatus identifies surface structures present on the outer surface of the cylinder, while a separate double pass cylindrical mirror analyzer AES verifies surface cleanliness. A supersonic molecular beam, skimmed by a rectangular slot, impinges molecules on a narrow longitudinal strip of the surface. Here, we use the King and Wells technique to demonstrate how surface structure influences the dissociation probability of deuterium at various kinetic energies. Finally, we introduce spatially-resolved temperature programmed desorption from areas exposed to the supersonic molecular beam to show how surface structures influence desorption features.

  12. Safety evaluation of interim stabilization of non-stabilized single-shell watch list tanks

    SciTech Connect

    Stahl, S.M.

    1994-12-30

    The report provides a summation of the status of safety issues associated with interim stabilization of Watch List SSTs (organic, ferrocyanide, and flammable gas), as extracted from recent safety analyses, including the Tank Farms Accelerated Safety Analysis efforts.

  13. A single-nanoparticle NO2 gas sensor constructed using active molecular plasmonics.

    PubMed

    Chen, Lichan; Wu, Bo; Guo, Longhua; Tey, Ruiwen; Huang, Youju; Kim, Dong-Hwan

    2015-01-25

    A single-nanoparticle plasmonic sensor for the sensitive detection of gas molecules (NO2) has been constructed. Taking advantage of active molecular plasmonics, the analyte selectively triggers a measurable spectral shift of ferrocene-modified single gold nanorods.

  14. Hybrid Co3O4/SnO2 Core-Shell Nanospheres as Real-Time Rapid-Response Sensors for Ammonia Gas.

    PubMed

    Wang, Lili; Lou, Zheng; Zhang, Rui; Zhou, Tingting; Deng, Jianan; Zhang, Tong

    2016-03-01

    Novel hybrid Co3O4/SnO2 core-shell nanospheres have been effectively realized by a one-step hydrothermal, template-free preparation method. Our strategy involves a simple fabrication scheme that entails the coating of natural cross-link agents followed by electrostatic interaction between the positive charges of Sn and Co ions and the negative charge of glutamic acid. The core-shell architecture enables novel flexibility of gas sensor surfaces compared to commonly used bulk materials. The highly efficient charge transfer and unique structure are key to ensuring the availability of high response and rapid-response speed. It demonstrates how hybrid core-shell nanospheres can be used as an advance function material to fabricate electrical sensing devices that may be useful as gas sensors.

  15. Luminescence and electrical properties of single ZnO/MgO core/shell nanowires

    SciTech Connect

    Grinblat, Gustavo; Comedi, David; Bern, Francis; Barzola-Quiquia, José; Esquinazi, Pablo; Tirado, Mónica

    2014-03-10

    To neutralise the influence of the surface of ZnO nanowires for photonics and optoelectronic applications, we have covered them with insulating MgO film and individually contacted them for electrical characterisation. We show that such a metal-insulator-semiconductor-type nanodevice exhibits a high diode ideality factor of 3.4 below 1 V. MgO shell passivates ZnO surface states and provides confining barriers to electrons and holes within the ZnO core, favouring excitonic ultraviolet radiative recombination, while suppressing defect-related luminescence in the visible and improving electrical conductivity. The results indicate the potential use of ZnO/MgO nanowires as a convenient building block for nano-optoelectronic devices.

  16. FRACTIONAL CRYSTALLIZATION OF HANFORD SINGLE SHELL TANK (SST) WASTES LABORATORY DEVELOPMENT

    SciTech Connect

    HERTING, D.L.

    2006-12-05

    Laboratory studies demonstrate that fractional crystallization is a viable process for separating Hanford medium-curie waste into high-curie and low-curie fractions. The product salt from the crystallization process qualifies as low-curie feed to a supplemental treatment system (e.g., bulk vitrification). The high-curie raffinate is returned to the double-shell tank system, eventually to be sent as feed to the Waste Treatment and Immobilization Plant. Process flowsheet tests were designed with the aid of thermodynamic chemical modeling. Laboratory equipment design and test procedures were developed using simulated tank waste samples. Proof-of-concept flowsheet tests were carried out in a shielded hot cell using actual tank waste samples. Data from both simulated waste tests and actual tank waste tests demonstrate that the process exceeded all of the separation criteria established for the program.

  17. Design and Testing of a Shell-Flow Hollow-Fiber Venting Gas Trap

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Cross, Cindy; Hansen, Scott; Vogel, Matthew; Dillon, Paul

    2013-01-01

    A Venting Gas Trap (VGT) was designed, built, and tested at NASA Johnson Space Center to eliminate dissolved and free gas from the circulating coolant loop of the Orion Environmental Control Life Support System. The VGT was downselected from two different designs. The VGT has robust operation, and easily met all the Orion requirements, especially size and weight. The VGT has a novel design with the gas trap made of a five-layer spiral wrap of porous hydrophobic hollow fibers that form a cylindrically shaped curtain terminated by a dome-shaped distal plug. Circulating coolant flows into the center of the cylindrical curtain and flows between the hollow fibers, around the distal plug, and exits the VGT outlet. Free gas is forced by the coolant flow to the distal plug and brought into contact with hollow fibers. The proximal ends of the hollow fibers terminate in a venting chamber that allows for rapid venting of the free gas inclusion, but passively limits the external venting from the venting chamber through two small holes in the event of a long-duration decompression of the cabin. The VGT performance specifications were verified in a wide range of flow rates, bubble sizes, and inclusion volumes. Long-duration and integrated Orion human tests of the VGT are also planned for the coming year.

  18. Reconstruction of the Orientation Distribution Function in Single and Multiple Shell Q-Ball Imaging within Constant Solid Angle

    PubMed Central

    Aganj, Iman; Lenglet, Christophe; Sapiro, Guillermo; Yacoub, Essa; Ugurbil, Kamil; Harel, Noam

    2010-01-01

    Q-ball imaging (QBI) is a high angular resolution diffusion imaging (HARDI) technique which has been proven very successful in resolving multiple intravoxel fiber orientations in MR images. The standard computation of the orientation distribution function (ODF, the probability of diffusion in a given direction) from q-ball data uses linear radial projection, neglecting the change in the volume element along each direction. This results in spherical distributions that are different from the true ODFs. For instance, they are neither normalized nor as sharp as expected, and generally require post-processing, such as artificial sharpening. In this paper, a new technique is proposed that, by considering the solid angle factor, uses the mathematically correct definition of the ODF and results in a dimensionless and normalized ODF expression. Our model is flexible enough so that ODFs can be estimated either from single q-shell datasets, or by exploiting the greater information available from multiple q-shell acquisitions. We show that the latter can be achieved by using a more accurate multi-exponential model for the diffusion signal. The improved performance of the proposed method is demonstrated on artificial examples and high-resolution HARDI data acquired on a 7T magnet. PMID:20535807

  19. Adsorption of two gas molecules at a single metal site in a metal–organic framework

    SciTech Connect

    Runčevski, Tomče; Kapelewski, Matthew T.; Torres-Gavosto, Rodolfo M.; Tarver, Jacob D.; Brown, Craig M.; Long, Jeffrey R.

    2016-01-01

    One strategy to markedly increase the gas storage capacity of metal-organic frameworks is to introduce coordinatively-unsaturated metal centers capable of binding multiple gas molecules. Herein, we provide an initial demonstration that a single metal site within a framework can support the terminal coordination of two gas molecules--specifically hydrogen, methane, or carbon dioxide.

  20. Adsorption of two gas molecules at a single metal site in a metal–organic framework

    SciTech Connect

    Runčevski, Tomče; Kapelewski, Matthew T.; Torres-Gavosto, Rodolfo M.; Tarver, Jacob D.; Brown, Craig M.; Long, Jeffrey R.

    2016-11-21

    One strategy to markedly increase the gas storage capacity of metal–organic frameworks is to introduce coordinatively-unsaturated metal centers capable of binding multiple gas molecules. Herein, we provide an initial demonstration that a single metal site within a framework can support the terminal coordination of two gas molecules—specifically hydrogen, methane, or carbon dioxide.

  1. The Assessment for Sensitivity of a NO2 Gas Sensor with ZnGa2O4/ZnO Core-Shell Nanowires—a Novel Approach

    PubMed Central

    Chen, I-Cherng; Lin, Shiu-Shiung; Lin, Tsao-Jen; Hsu, Cheng-Liang; Hsueh, Ting Jen; Shieh, Tien-Yu

    2010-01-01

    The application of novel core-shell nanowires composed of ZnGa2O4/ZnO to improve the sensitivity of NO2 gas sensors is demonstrated in this study. The growth of ZnGa2O4/ZnO core-shell nanowires is performed by reactive evaporation on patterned ZnO:Ga/SiO2/Si templates at 600 °C. This is to form the homogeneous structure of the sensors investigated in this report to assess their sensitivity in terms of NO2 detection. These novel NO2 gas sensors were evaluated at working temperatures of 25 °C and at 250 °C, respectively. The result reveals the ZnGa2O4/ZnO core-shell nanowires present a good linear relationship (R2 > 0.99) between sensitivity and NO2 concentration at both working temperatures. These core-shell nanowire sensors also possess the highest response (<90 s) and recovery (<120 s) values with greater repeatability seen for NO2 sensors at room temperature, unlike traditional sensors that only work effectively at much higher temperatures. The data in this study indicates the newly-developed ZnGa2O4/ZnO core-shell nanowire based sensors are highly promising for industrial applications. PMID:22319286

  2. Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

    SciTech Connect

    Cantrell, Kirk J.; Zachara, John M.; Dresel, P. Evan; Krupka, Kenneth M.; Serne, R. Jeffrey

    2007-09-28

    This data package discusses the geochemistry of vadose zone sediments beneath the single-shell tank farms at the U.S. Department of Energy’s (DOE’s) Hanford Site. The purpose of the report is to provide a review of the most recent and relevant geochemical process information available for the vadose zone beneath the single-shell tank farms and the Integrated Disposal Facility. Two companion reports to this one were recently published which discuss the geology of the farms (Reidel and Chamness 2007) and groundwater flow and contamination beneath the farms (Horton 2007).

  3. Groundwater quality assessment plan for single-shell waste management area B-BX-BY at the Hanford Site

    SciTech Connect

    SM Narbutovskih

    2000-03-31

    Pacific Northwest National Laboratory conducted a first determination groundwater quality assessment at the Hanford Site. This work was performed for the US Department of Energy, Richland Operations Office, in accordance with the Federal Facility Compliance Agreement during the time period 1996--1998. The purpose of the assessment was to determine if waste from the Single-Shell Tank (SST) Waste Management Area (WMA) B-BX-BY had entered the groundwater at levels above the drinking water standards (DWS). The resulting assessment report documented evidence demonstrating that waste from the WMA has, most likely, impacted groundwater quality. Based on 40 CFR 265.93 [d] paragraph (7), the owner-operator must continue to make the minimum required determinations of contaminant level and of rate/extent of migrations on a quarterly basis until final facility closure. These continued determinations are required because the groundwater quality assessment was implemented prior to final closure of the facility.

  4. Phase 1 RCRA Facility Investigation & Corrective Measures Study Work Plan for Single Shell Tank (SST) Waste Management Areas

    SciTech Connect

    MCCARTHY, M.M.

    1999-08-01

    This document is the master work plan for the Resource Conservation and Recovery Act of 1976 (RCRA) Corrective Action Program (RCAP) for single-shell tank (SST) farms at the US. Department of Energy's (DOE'S) Hanford Site. The DOE Office of River Protection (ORP) initiated the RCAP to address the impacts of past and potential future tank waste releases to the environment. This work plan defines RCAP activities for the four SST waste management areas (WMAs) at which releases have contaminated groundwater. Recognizing the potential need for future RCAP activities beyond those specified in this master work plan, DOE has designated the currently planned activities as ''Phase 1.'' If a second phase of activities is needed for the WMAs addressed in Phase 1, or if releases are detected at other SST WMAs, this master work plan will be updated accordingly.

  5. Compact Ag@Fe3O4 Core-shell Nanoparticles by Means of Single-step Thermal Decomposition Reaction

    NASA Astrophysics Data System (ADS)

    Brollo, Maria Eugênia F.; López-Ruiz, Román; Muraca, Diego; Figueroa, Santiago J. A.; Pirota, Kleber R.; Knobel, Marcelo

    2014-10-01

    A temperature pause introduced in a simple single-step thermal decomposition of iron, with the presence of silver seeds formed in the same reaction mixture, gives rise to novel compact heterostructures: brick-like Ag@Fe3O4 core-shell nanoparticles. This novel method is relatively easy to implement, and could contribute to overcome the challenge of obtaining a multifunctional heteroparticle in which a noble metal is surrounded by magnetite. Structural analyses of the samples show 4 nm silver nanoparticles wrapped within compact cubic external structures of Fe oxide, with curious rectangular shape. The magnetic properties indicate a near superparamagnetic like behavior with a weak hysteresis at room temperature. The value of the anisotropy involved makes these particles candidates to potential applications in nanomedicine.

  6. Compact Ag@Fe3O4 core-shell nanoparticles by means of single-step thermal decomposition reaction.

    PubMed

    Brollo, Maria Eugênia F; López-Ruiz, Román; Muraca, Diego; Figueroa, Santiago J A; Pirota, Kleber R; Knobel, Marcelo

    2014-10-30

    A temperature pause introduced in a simple single-step thermal decomposition of iron, with the presence of silver seeds formed in the same reaction mixture, gives rise to novel compact heterostructures: brick-like Ag@Fe3O4 core-shell nanoparticles. This novel method is relatively easy to implement, and could contribute to overcome the challenge of obtaining a multifunctional heteroparticle in which a noble metal is surrounded by magnetite. Structural analyses of the samples show 4 nm silver nanoparticles wrapped within compact cubic external structures of Fe oxide, with curious rectangular shape. The magnetic properties indicate a near superparamagnetic like behavior with a weak hysteresis at room temperature. The value of the anisotropy involved makes these particles candidates to potential applications in nanomedicine.

  7. Accelerated safety analyses - structural analyses Phase I - structural sensitivity evaluation of single- and double-shell waste storage tanks

    SciTech Connect

    Becker, D.L.

    1994-11-01

    Accelerated Safety Analyses - Phase I (ASA-Phase I) have been conducted to assess the appropriateness of existing tank farm operational controls and/or limits as now stipulated in the Operational Safety Requirements (OSRs) and Operating Specification Documents, and to establish a technical basis for the waste tank operating safety envelope. Structural sensitivity analyses were performed to assess the response of the different waste tank configurations to variations in loading conditions, uncertainties in loading parameters, and uncertainties in material characteristics. Extensive documentation of the sensitivity analyses conducted and results obtained are provided in the detailed ASA-Phase I report, Structural Sensitivity Evaluation of Single- and Double-Shell Waste Tanks for Accelerated Safety Analysis - Phase I. This document provides a summary of the accelerated safety analyses sensitivity evaluations and the resulting findings.

  8. Preliminary recommendations on the design of the characterization program for the Hanford Site single-shell tanks: A system analysis

    SciTech Connect

    Buck, J.W.; Peffers, M.S.; Hwang, S.T.

    1991-11-01

    The work described in this volume was conducted by Pacific Northwest Laboratory to provide preliminary recommendations on data quality objectives (DQOs) to support the Waste Characterization Plan (WCP) and closure decisions for the Hanford Site single-shell tanks (SSTs). The WCP describes the first of a two-phase characterization program that will obtain information to assess and implement disposal options for SSTs. This work was performed for the Westinghouse Hanford Company (WHC), the current operating contractor on the Hanford Site. The preliminary DQOs contained in this volume deal with the analysis of SST wastes in support of the WCP and final closure decisions. These DQOs include information on significant contributors and detection limit goals (DLGs) for SST analytes based on public health risk.

  9. Compact Ag@Fe3O4 Core-shell Nanoparticles by Means of Single-step Thermal Decomposition Reaction

    PubMed Central

    Brollo, Maria Eugênia F.; López-Ruiz, Román; Muraca, Diego; Figueroa, Santiago J. A.; Pirota, Kleber R.; Knobel, Marcelo

    2014-01-01

    A temperature pause introduced in a simple single-step thermal decomposition of iron, with the presence of silver seeds formed in the same reaction mixture, gives rise to novel compact heterostructures: brick-like Ag@Fe3O4 core-shell nanoparticles. This novel method is relatively easy to implement, and could contribute to overcome the challenge of obtaining a multifunctional heteroparticle in which a noble metal is surrounded by magnetite. Structural analyses of the samples show 4 nm silver nanoparticles wrapped within compact cubic external structures of Fe oxide, with curious rectangular shape. The magnetic properties indicate a near superparamagnetic like behavior with a weak hysteresis at room temperature. The value of the anisotropy involved makes these particles candidates to potential applications in nanomedicine. PMID:25354532

  10. Synthesis, Characterization and Gas Sensing Properties of Ag@α-Fe2O3 Core–Shell Nanocomposites

    PubMed Central

    Mirzaei, Ali; Janghorban, Kamal; Hashemi, Babak; Bonavita, Anna; Bonyani, Maryam; Leonardi, Salvatore Gianluca; Neri, Giovanni

    2015-01-01

    Ag@α-Fe2O3 nanocomposite having a core–shell structure was synthesized by a two-step reduction-sol gel approach, including Ag nanoparticles synthesis by sodium borohydride as the reducing agent in a first step and the subsequent mixing with a Fe+3 sol for α-Fe2O3 coating. The synthesized Ag@α-Fe2O3 nanocomposite has been characterized by various techniques, such as SEM, TEM and UV-Vis spectroscopy. The electrical and gas sensing properties of the synthesized composite towards low concentrations of ethanol have been evaluated. The Ag@α-Fe2O3 nanocomposite showed better sensing characteristics than the pure α-Fe2O3. The peculiar hierarchical nano-architecture and the chemical and electronic sensitization effect of Ag nanoparticles in Ag@α-Fe2O3 sensors were postulated to play a key role in modulating gas-sensing properties in comparison to pristine α-Fe2O3 sensors. PMID:28347032

  11. Converting oil shale to liquid fuels: energy inputs and greenhouse gas emissions of the Shell in situ conversion process.

    PubMed

    Brandt, Adam R

    2008-10-01

    Oil shale is a sedimentary rock that contains kerogen, a fossil organic material. Kerogen can be heated to produce oil and gas (retorted). This has traditionally been a CO2-intensive process. In this paper, the Shell in situ conversion process (ICP), which is a novel method of retorting oil shale in place, is analyzed. The ICP utilizes electricity to heat the underground shale over a period of 2 years. Hydrocarbons are produced using conventional oil production techniques, leaving shale oil coke within the formation. The energy inputs and outputs from the ICP, as applied to oil shales of the Green River formation, are modeled. Using these energy inputs, the greenhouse gas (GHG) emissions from the ICP are calculated and are compared to emissions from conventional petroleum. Energy outputs (as refined liquid fuel) are 1.2-1.6 times greater than the total primary energy inputs to the process. In the absence of capturing CO2 generated from electricity produced to fuel the process, well-to-pump GHG emissions are in the range of 30.6-37.1 grams of carbon equivalent per megajoule of liquid fuel produced. These full-fuel-cycle emissions are 21%-47% larger than those from conventionally produced petroleum-based fuels.

  12. Single GaAs/GaAsP coaxial core-shell nanowire lasers.

    PubMed

    Hua, Bin; Motohisa, Junichi; Kobayashi, Yasunori; Hara, Shinjiroh; Fukui, Takashi

    2009-01-01

    Highly uniform GaAs/GaAsP coaxial nanowires were prepared via selective-area metal organic vapor phase epitaxy. Photoluminescence spectra from a single nanowire indicate that the obtained heterostructures can produce near-infrared (NIR) lasing under pulsed light excitation. The end facets of a single nanowire form a natural mirror surface to create an axial cavity, which realizes resonance and give stimulated emission. This study is a considerable advance toward the realization of nanowire-based NIR light sources.

  13. Mechanistic analysis of double-shell tank gas release. Progress report, November 1990

    SciTech Connect

    Allemann, R.T.; Antoniak, Z.I.; Friley, J.R.; Haines, C.E.; Liljegren, L.M.; Somasundaram, S.

    1991-12-01

    Pacific Northwest Laboratory (PNL) is studying possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at Hanford. This study is being conducted for Westinghouse Hanford Company (WHC), a contractor for the US Department of Energy (DOE). This interim report discusses the work done through November 1990. Safe management of the wastes at Hanford depends on an understanding of the chemical and physical mechanisms that take place in the waste tanks. An example of the need to understand these mechanisms is tank 101-SY. The waste in this tank is generating and periodically releasing potentially flammable gases into the tank vent system according to observations of the tank. How these gases are generated and become trapped, the causes of periodic release, and the mechanism of the release are not known in detail. In order to develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood.

  14. Vibration of a Singly-curved Thin Shell Reflector with a Unidirectional Tension Field

    NASA Technical Reports Server (NTRS)

    Williams, R. Brett; Klein, Kerry J.; Agnes, Gregory S.

    2006-01-01

    Increased science requirements for space-based instruments over the past few decades have lead to the increased popularity of deployable space structures constructed from thin, lightweight films. Such structures offer both low mass and the ability to be stowed inside conventional launch vehicles. The analysis in this work pertains to large, singly-curved lightweight deployable reflectors commonly used in radar antennas and space telescopes. These types of systems, which can vary a great deal in size, often have frequency requirement that must be met. This work discusses two missions that utilize this type of aperture technology, and then develops a Rayleigh-Ritz model that predicts the natural frequencies and mode shapes for a (nearly) flat and singly-curved reflector with unidirectional in-plane loading. The results are compared with NASTRAN analyses.

  15. Sensitivity of Λ single-particle energies to the ΛN spin-orbit coupling and to nuclear core structure in p-shell and sd-shell hypernuclei

    NASA Astrophysics Data System (ADS)

    Veselý, P.; Hiyama, E.; Hrtánková, J.; Mareš, J.

    2016-10-01

    We introduce a mean field model based on realistic 2-body baryon interactions and calculate spectra of a set of p-shell and sd-shell Λ hypernuclei - 13ΛC, 17ΛO, 21ΛNe, 29ΛSi and 41ΛCa. The hypernuclear spectra are compared with the results of a relativistic mean field (RMF) model and available experimental data. The sensitivity of Λ single-particle energies to the nuclear core structure is explored. Special attention is paid to the effect of spin-orbit ΛN interaction on the energy splitting of the Λ single particle levels 0p3/2 and 0p1/2. In particular, we analyze the contribution of the symmetric (SLS) and the anti-symmetric (ALS) spin-orbit terms to the energy splitting. We give qualitative predictions for the calculated hypernuclei.

  16. Critical evaluation of current cleaning protocols for foraminiferal trace metal analyses using single shell Laser-Ablation -ICP measurements

    NASA Astrophysics Data System (ADS)

    Sadekov, A.; Eggins, S. M.; Misra, S.; Kerr, J.; Greaves, M.; Elderfield, H.

    2012-12-01

    Trace element compositions of foraminiferal calcite have been widely used as proxies for past ocean conditions. However, it has been shown that the presence of detrital material, particulate organic matter and diagenically-precipitated overgrowth on test surfaces significantly limit the accuracy of trace element analyses. A number of cleaning methods had been proposed to remove impurities from foraminiferal calcite but their relative effectiveness for foraminiferal trace metal analyses is still debatable. In this work, we employed the microanalytical technique Laser Ablation ICP-MS to compare the most commonly-used cleaning protocols. Distribution of Ca, Mg, Mn, Zn, Ba, Sr, Li, B, Fe, Al across tests of Orbulina universa from modern and Holocene sediments were analysed before and after each cleaning step. The use of Laser Ablation ICP-MS provides accurate and direct comparison of the effectiveness of each cleaning protocol, which was applied to fragments of a single foraminifera test. We also present results obtained using a novel automated cleaning device, "fOraccle", for cleaning single shell and bulk foraminiferal samples. This instrument minimises manual handling of chemical reagents during cleaning, thereby improving reproducibility of the Me/Ca measurements. Based on these results, we will discuss the composition of surface contamination on foraminiferal tests as well as possible ways to improve current cleaning protocols.

  17. Gas phase synthesis of core-shell Fe@FeO x magnetic nanoparticles into fluids

    NASA Astrophysics Data System (ADS)

    Aktas, Sitki; Thornton, Stuart C.; Binns, Chris; Denby, Phil

    2016-12-01

    Sorbitol, short chain molecules, have been used to stabilise of Fe@FeO x nanoparticles produced in the gas phase under the ultra-high vacuum (UHV) conditions. The sorbitol coated Fe@FeO x nanoparticles produced by our method have a narrow size distribution with a hydrodynamic diameter of 35 nm after NaOH is added to the solution. Magnetisation measurement shows that the magnetic nanoparticles are superparamagnetic at 100 K and demonstrate hysteresis at 5 K with an anisotropy constant of 5.31 × 104 J/m3 (similar to bulk iron). Also, it is shown that sorbitol is only suitable for stabilising the Fe@FeO x suspensions, and it does not prevent further oxidation of the metallic Fe core. According to MRI measurement, the nanoparticles have a high transverse relaxation rate of 425 mM-1 s-1.

  18. Simulations of Ar gas-puff Z-pinch radiation sources with double shells and central jets on the Z generator

    NASA Astrophysics Data System (ADS)

    Tangri, V.; Harvey-Thompson, A. J.; Giuliani, J. L.; Thornhill, J. W.; Velikovich, A. L.; Apruzese, J. P.; Ouart, N. D.; Dasgupta, A.; Jones, B.; Jennings, C. A.

    2016-10-01

    Radiation-magnetohydrodynamic simulations using the non-local thermodynamic equilibrium Mach2-Tabular Collisional-Radiative Equilibrium code in (r, z) geometry are performed for two pairs of recent Ar gas-puff Z-pinch experiments on the refurbished Z generator with an 8 cm diameter nozzle. One pair of shots had an outer-to-inner shell mass ratio of 1:1.6 and a second pair had a ratio of 1:1. In each pair, one of the shots had a central jet. The experimental trends in the Ar K-shell yield and power are reproduced in the calculations. However, the K-shell yield and power are significantly lower than the other three shots for the case of a double-shell puff of 1:1 mass ratio and no central jet configuration. Further simulations of a hypothetical experiment with the same relative density profile of this configuration, but higher total mass, show that the coupled energy from the generator and the K-shell yield can be increased to levels achieved in the other three configurations, but not the K-shell power. Based on various measures of effective plasma radius, the compression in the 1:1 mass ratio and no central jet case is found to be less because the plasma inside the magnetic piston is hotter and of lower density. Because of the reduced density, and the reduced radiation cooling (which is proportional to the square of the density), the core plasma is hotter. Consequently, for the 1:1 outer-to-inner shell mass ratio, the load mass controls the yield and the center jet controls the power.

  19. DNA origami based Au-Ag-core-shell nanoparticle dimers with single-molecule SERS sensitivity

    NASA Astrophysics Data System (ADS)

    Prinz, J.; Heck, C.; Ellerik, L.; Merk, V.; Bald, I.

    2016-03-01

    DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled.DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled. Electronic supplementary information (ESI) available: Additional information about materials and methods, designs of DNA origami templates, height profiles, additional SERS spectra, assignment of DNA

  20. Characterization of Solids in Residual Wastes from Single-Shell Tanks at the Hanford Site, Washington, USA - 9277

    SciTech Connect

    Krupka, Kenneth M.; Cantrell, Kirk J.; Schaef, Herbert T.; Arey, Bruce W.; Heald, Steve M.; Deutsch, William J.; Lindberg, Michael J.

    2009-06-01

    Solid-phase characterization methods have been used in an ongoing study of residual wastes (i.e., waste remaining after final retrieval operations) from the underground single-shell storage tanks 241-C-103, 241-C-106, 241-C-202, 241-C-203, and 241-S-112 at the U.S. Department of Energy’s Hanford Site in Washington State. The results of studies completed to date show significant variability in the compositions of those residual wastes and the compositions, morphologies, and crystallinities of the individual phases that make up these wastes. These differences undoubtedly result from the various waste types stored and transferred in and out each tank and the sluicing and retrieval operations used for waste retrieval. Our studies indicate that these residual wastes are chemically-complex assemblages of crystalline and amorphous solids that contain contaminants as discrete phases and/or co-precipitated within oxide phases. Depending on the specific tank, various solids (e.g., gibbsite; boehmite; dawsonite; cancrinite; Fe oxides such as hematite, goethite, and maghemite; rhodochrosite; lindbergite; whewellite; nitratine; and numerous amorphous or poorly crystalline phases) have been identified by X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy in residual wastes studied to date. Our studies also show that contact of residual wastes with Ca(OH)2- and CaCO3-saturated aqueous solutions, which were used as surrogates for the compositions of pore-fluid leachants derived from young and aged cements respectively, may alter the compositions of solid phases present in the contacted wastes. Fe oxides/hydroxides have been identified in all residual wastes studied to date. They occur in these wastes as discrete particles, particles intergrown within a matrix of other phases, and surface coatings on other particles or particle aggregates. These Fe oxides/hydroxides typically contain trace concentrations of other transition metals, such Cr, Mn

  1. Evaluation of strengthening mechanisms in calcite single crystals from mollusk shells.

    PubMed

    Kunitake, Miki E; Mangano, Lauren M; Peloquin, John M; Baker, Shefford P; Estroff, Lara A

    2013-02-01

    Biogenic single-crystal calcite is often reported to be harder and tougher than geologic calcite in the form of Iceland spar. However, the mechanistic origins of the superior mechanical properties of the biogenic materials are still debated. We investigate the hardness and modulus of biogenic calcite from the prismatic layer of the mollusk Atrina rigida compared with a pure geologic calcite, Iceland spar. On the {001} face, biogenic calcite is found to be 50-70% harder than geologic calcite. This range is due to the fact that changes in azimuthal angle of the indenter tip lead to a hardness variation of ∼20% in A. rigida but only ∼7% in Iceland spar. The higher hardness and increased anisotropy of biogenic calcite could be accounted for by hardening mechanisms based on hindered dislocation motion rather than crack deflection.

  2. Simulations of Ar gas-puff Z-pinch radiation sources with double shells and central jets on the Z generator

    SciTech Connect

    Tangri, V.; Harvey-Thompson, Adam James; Giuliani, J. L.; Thornhill, J. W.; Velikovich, A. L.; Apruzese, J. P.; Quart, N. D.; DasGupta, A.; Jones, Brent M.; Jennings, Christopher Ashley

    2016-10-19

    Radiation-magnetohydrodynamic simulations using the non-LTE Mach2-TCRE code in (r,z) geometry are performed for two pairs of recent Ar gas-puff Z-pinch experiments on the refurbished Z generator with an 8 cm diameter nozzle. One pair of shots had an outer-to-inner shell mass ratio of 1:1.6 and a second pair had a ratio of 1:1.

  3. Simulations of Ar gas-puff Z-pinch radiation sources with double shells and central jets on the Z generator

    DOE PAGES

    Tangri, V.; Harvey-Thompson, Adam James; Giuliani, J. L.; ...

    Radiation-magnetohydrodynamic simulations using the non-LTE Mach2-TCRE code in (r,z) geometry are performed for two pairs of recent Ar gas-puff Z-pinch experiments on the refurbished Z generator with an 8 cm diameter nozzle. One pair of shots had an outer-to-inner shell mass ratio of 1:1.6 and a second pair had a ratio of 1:1.

  4. Comparative Study of δ18O Compositions Determined for Fossil Holocene Planktic Foraminifera by In Situ SIMS Measurements and Standard Gas-Source IRMS Bulk Shell Analyses

    NASA Astrophysics Data System (ADS)

    Wycech, J.; Kelly, D. C.; Kozdon, R.; Kitajima, K.; Spero, H. J.; Orland, I. J.; Kita, N.; Valley, J. W.

    2015-12-01

    The use of SIMS to perform in situ δ18O analyses on micron-scale domains within individual foraminiferal shells is an emerging technique that holds much promise for elucidating new paleoclimate information from deep-sea records. High precision and accuracy are possible for inorganic calcite, but continued testing is essential to establish the accuracy of this novel technique for biocarbonates; hence, a comparative study was conducted using both in situ SIMS (IMS 1280) and standard gas-source IRMS analyses to measure the δ18O in the same chamber of a foraminifera shell. An initial experiment was performed on 18 Orbulina universa shells (~600 μm) exhibiting varying states of preservation (3 well-preserved glassy, 1 intermediate, 14 frosty) handpicked from the uppermost 2 cm (Holocene) of a piston core (PC9) retrieved from the northwestern Atlantic. The spherical chamber of each shell was manually broken into smaller fragments with the majority of the fragments pooled for δ18O analysis by IRMS, and a remaining fragment cast in epoxy for SIMS. Comparison of average SIMS δ18O values to corresponding IRMS δ18O values for the same chamber reveals a linear relationship across a 3‰ range in glassy and frosty shells with the SIMS values being 0.9 ± 0.7‰ (2SD) lower. This 0.9‰ offset is also seen in O. universa shells (1 glassy, 3 intermediate, 10 frosty) that have undergone hydrogen peroxide cleaning and sonication. The δ18O offset is being further investigated using manually fragmented O. universa shells from the core-top of PC9 that have been vacuum roasted as well as cultured specimens grown under controlled conditions. Through these additional experiments we are exploring possible offset mechanisms including: errors in SIMS and gas-source analysis; differences between the coarsely crystalline homogeneous SIMS standards and complex biocarbonate samples; and zoning in shells due to growth, diagenesis or other components not targeted by SIMS.

  5. Implementation of single-shot ellipsometry on gas gun experiments

    NASA Astrophysics Data System (ADS)

    Grant, Sean; Ao, Tommy; Bernstein, Aaron; Ditmire, Todd; Dolan, Dan; Lin, Jung-Fu; Seagle, Chris; Davis, Jean-Paul

    2017-01-01

    We have built and implemented a time-resolved ellipsometry diagnostic for dynamic material properties experiments at Sandia National Laboratories. This diagnostic measures the complex dielectric value of a sample experiencing dynamic compression, with a time resolution of a few nanoseconds. We show and discuss the dynamic ellipsometry measurements taken from shock loading experiments on a gas gun. This work is relevant to geophysical materials at high pressure-temperature conditions.

  6. Atomic model of CPV reveals the mechanism used by this single-shelled virus to economically carry out functions conserved in multishelled reoviruses.

    PubMed

    Yu, Xuekui; Ge, Peng; Jiang, Jiansen; Atanasov, Ivo; Zhou, Z Hong

    2011-05-11

    Unlike the multishelled viruses in the Reoviridae, cytoplasmic polyhedrosis virus (CPV) is single shelled, yet stable and fully capable of carrying out functions conserved within Reoviridae. Here, we report a 3.1 Å resolution cryo electron microscopy structure of CPV and derive its atomic model, consisting of 60 turret proteins (TPs), 120 each of capsid shell proteins (CSPs) and large protrusion proteins (LPPs). Two unique segments of CSP contribute to CPV's stability: an inserted protrusion domain interacting with neighboring proteins, and an N-anchor tying up CSPs together through strong interactions such as β sheet augmentation. Without the need to interact with outer shell proteins, LPP retains only the N-terminal two-third region containing a conserved helix-barrel core and interacts exclusively with CSP. TP is also simplified, containing only domains involved in RNA capping. Our results illustrate how CPV proteins have evolved in a coordinative manner to economically carry out their conserved functions.

  7. Self-assembled single-mode micro-lasers of ``giant'' CdSe/CdS core/shell quantum dots

    NASA Astrophysics Data System (ADS)

    Liao, Chen; Zhang, Jiayu

    So-called ``giant'' quantum dots (g-QDs) as optical gain media have attracted much attention due to their near elimination of nonradiative Auger effects. In the present work, phase-pure wurtzite CdSe/CdS core/shell QDs with controlled shell thickness are successfully synthesized, and the threshold of amplified spontaneous emission (ASE) of the films of this series of QDs is measured. The threshold of ASE is decreased dramatically with the CdS shell growth towards 11 monolayers (MLs) (21 μJ/cm2) , but increased with the further shell growth. The effects of the overlap degree of electron and hole wave functions, surface states, and absorption cross-section are discussed to explain the ASE properties of the QDs. Moreover, the low-threshold gain of the CdSe/CdS core/shell (11 MLs) g-QDs is exploited to fabricate micro-lasers solely by deposition of small droplets of QDs solution onto glass substrates. The evaporation dynamics of the droplets are governed by the ``coffee-ring effect'' which leads to the formation of well defined micron-size rings. The self-assembled coffee-ring micro-lasers display single-mode operation and a very low threshold of 3 μJ/cm2. Herein, an innovative, simple and reliable method to produce micro-lasers based on CdSe/CdS g-QDs is presented.

  8. DFT study of Fe-Ni core-shell nanoparticles: Stability, catalytic activity, and interaction with carbon atom for single-walled carbon nanotube growth

    NASA Astrophysics Data System (ADS)

    Yang, Zhimin; Wang, Qiang; Shan, Xiaoye; Li, Wei-qi; Chen, Guang-hui; Zhu, Hongjun

    2015-02-01

    Metal catalysts play an important role in the nucleation and growth of single-walled carbon nanotubes (SWCNTs). It is essential for probing the nucleation and growth mechanism of SWCNTs to fundamentally understand the properties of the metal catalysts and their interaction with carbon species. In this study, we systematically studied the stability of 13- and 55-atom Fe and Fe-Ni core-shell particles as well as these particles interaction with the carbon atoms using the density functional theory calculations. Icosahedral 13- and 55-atom Fe-Ni core-shell bimetallic particles have higher stability than the corresponding monometallic Fe and Ni particles. Opposite charge transfer (or distribution) in these particles leads to the Fe surface-shell displays a positive charge, while the Ni surface-shell exhibits a negative charge. The opposite charge transfer would induce different chemical activities. Compared with the monometallic Fe and Ni particles, the core-shell bimetallic particles have weaker interaction with C atoms. More importantly, C atoms only prefer staying on the surface of the bimetallic particles. In contrast, C atoms prefer locating into the subsurface of the monometallic particles, which is more likely to form stable metal carbides. The difference of the mono- and bimetallic particles on this issue may result in different nucleation and growth mechanism of SWCNTs. Our findings provide useful insights for the design of bimetallic catalysts and a better understanding nucleation and growth mechanism of SWCNTs.

  9. Ultralow-Threshold Single-Mode Lasing from Phase-Pure CdSe/CdS Core/Shell Quantum Dots.

    PubMed

    Liao, Chen; Xu, Ruilin; Xu, Yanqing; Zhang, Chunfeng; Xiao, Min; Zhang, Lei; Lu, Changgui; Cui, Yiping; Zhang, Jiayu

    2016-12-15

    The development of colloidal quantum dot (QD) lasers is blocked by Auger recombination (AR). Here, phase-pure wurtzite CdSe/CdS core/shell QDs with controlled shell thickness are reported, which possess nearly defect-free core/shell interfaces. Benefiting from increased volume, electron-hole partial spatial separation, and nearly defect-free alloyed interface, this series of QDs exhibit a greater than 3 orders of magnitude decrease in AR rates with increasing shell thickness. Consequently, the amplified spontaneous emission threshold of the QDs with an 11 monolayer CdS shell is found to reach a minimum of 16 μJ cm(-2). A record long lifetime (>1000 ps) and extraordinarily large bandwidth (>170 nm) of optical gain are observed by employing ultrafast transient absorption spectroscopy. We leverage the low-threshold gain of the QDs to fabricate microlasers that display single-mode operation and an ultralow threshold of ∼2 μJ cm(-2). Our results represent a valuable step toward practical QD lasers.

  10. Surfactants at Single-Walled Carbon Nanotube-Water Interface: Physics of Surfactants, Counter-Ions, and Hydration Shell

    NASA Astrophysics Data System (ADS)

    Khare, Ketan S.; Phelan, Frederick R., Jr.

    Specialized applications of single-walled carbon nanotubes (SWCNTs) require an efficient and reliable method to sort these materials into monodisperse fractions with respect to their defining metrics (chirality, length, etc.) while retaining their physical and chemical integrity. A popular method to achieve this goal is to use surfactants that individually disperse SWCNTs in water and then to separate the resulting colloidal mixture into fractions that are enriched in monodisperse SWCNTs. Recently, experiments at NIST have shown that subtle point mutations of chemical groups in bile salt surfactants have a large impact on the hydrodynamic properties of SWCNT-surfactant complexes during ultracentrifugation. These results provide strong motivation for understanding the rich physics underlying the assembly of surfactants around SWCNTs, the structure and dynamics of counter ions around the resulting complex, and propagation of these effects into the first hydration shell. Here, all-atom molecular dynamics simulations are used to investigate the thermodynamics of SWCNT-bile salt surfactant complexes in water with an emphasis on the buoyant characteristics of the SWCNT-surfactant complexes. Simulation results will be presented along with a comparison with experimental data. Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States.

  11. RCRA Assessment Plan for Single-Shell Tank Waste Management Area B-BX-BY at the Hanford Site

    SciTech Connect

    Narbutovskih, Susan M.

    2006-09-29

    This document was prepared as a groundwater quality assessment plan revision for the single-shell tank systems in Waste Management Area B-BX-BY at the Hanford Site. Groundwater monitoring is conducted at this facility in accordance with 40 CFR Part 265, Subpart F. In FY 1996, the groundwater monitoring program was changed from detection-level indicator evaluation to a groundwater quality assessment program when elevated specific conductance in downgradient monitoring well 299 E33-32 was confirmed by verification sampling. During the course of the ensuing investigation, elevated technetium-99 and nitrate were observed above the drinking water standard at well 299-E33-41, a well located between 241-B and 241-BX Tank Farms. Earlier observations of the groundwater contamination and tank farm leak occurrences combined with a qualitative analysis of possible solutions, led to the conclusion that waste from the waste management area had entered the groundwater and were observed in this well. Based on 40 CFR 265.93 [d] paragraph (7), the owner-operator must continue to make the minimum required determinations of contaminant level and rate/extent of migrations on a quarterly basis until final facility closure. These continued determinations are required because the groundwater quality assessment was implemented prior to final closure of the facility.

  12. Radioactive air emissions notice of construction use of a portable exhauster on single shell tanks (SSTs) during salt well pumping

    SciTech Connect

    GRANDO, C.J.

    1999-11-18

    This document serves as a notice of construction (NOC), pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct, pursuant to 40 Code of Federal Regulations (CFR) 61.07, portable exhausters for use on single-shell tanks (SSTs) during salt well pumping. Table 1-1 lists 18 SSTs covered by this NOC. This NOC also addresses other activities that are performed in support of salt well pumping but do not require the application of a portable exhauster. Specifically this NOC analyzes the following three activities that have the potential for emissions. (1) Salt well pumping (i.e., the actual transferring of waste from one tank to another) under nominal tank operating conditions. Nominal tank operating conditions include existing passive breathing rates. (2) Salt well pumping (the actual transferring of waste from one tank to another) with use of a portable exhauster. (3) Use of a water lance on the waste to facilitate salt well screen and salt well jet pump installation into the waste. This activity is to be performed under nominal (existing passive breathing rates) tank operating conditions. The use of portable exhausters represents a cost savings because one portable exhauster can be moved back and forth between SSTs as schedules for salt well pumping dictate. A portable exhauster also could be used to simultaneously exhaust more than one SST during salt well pumping.

  13. Large optical Stark shifts in single quantum dots coupled to core-shell GaAs/AlGaAs nanowires.

    PubMed

    Yu, Ying; Wei, Yu-Ming; Wang, Jing; Li, Jia-Hua; Shang, Xiang-Jun; Ni, Hai-Qiao; Niu, Zhi-Chuan; Wang, Xue-Hua; Yu, Si-Yuan

    2017-04-12

    Nanowire quantum dots (NW-QDs) can be used for future compact and efficient optoelectronic devices. Many efforts have been made to control the QD states by inserting the QDs in doped structures and applying an electric field in a nanowire system. In this paper, we use down-conversion and up-conversion photoluminescence excitations to explore the optical and electronic properties of single quantum dots in GaAs/AlGaAs core-shell nanowires. We investigate a large optical Stark shift in this system as a new method to tune the QD states. When the tunable laser lies within the spectral bandwidth of ZB/WZ GaAs (780 nm-860 nm), we observe an extremely large optical Stark shift of 1.3 nm (0.5 nm) with increasing excitation power at a resonant wavelength of 800 nm (840 nm) in GaAs states. The ability to in situ control the energy states of self-catalyzed NW-QDs should open a new way for quantum light sources and nonlinear optics in a nanowire system.

  14. Synthesis of double-shelled SnO2 nano-polyhedra and their improved gas sensing properties

    NASA Astrophysics Data System (ADS)

    Bing, Yifei; Zeng, Yi; Liu, Chang; Qiao, Liang; Zheng, Weitao

    2015-02-01

    A new type of non-spherical SnO2 hollow structure with double-shelled and mesoporous shells was prepared via a sacrifice template strategy in the case of SnO2, which shows high response and good selectivity to toluene.

  15. Sulfonated poly(ether ether ketone)/polypyrrole core-shell nanofibers: a novel polymeric adsorbent/conducting polymer nanostructures for ultrasensitive gas sensors.

    PubMed

    Wang, Wei; Li, Zhenyu; Jiang, Tingting; Zhao, Zhiwei; Li, Ye; Wang, Zhaojie; Wang, Ce

    2012-11-01

    Conducting polymers-based gas sensors have attracted increasing research attention these years. The introduction of inorganic sensitizers (noble metals or inorganic semiconductors) within the conducting polymers-based gas sensors has been regarded as the generally effective route for further enhanced sensors. Here we demonstrate a novel route for highly-efficient conducting polymers-based gas sensors by introduction of polymeric sensitizers (polymeric adsorbent) within the conducting polymeric nanostructures to form one-dimensional polymeric adsorbent/conducting polymer core-shell nanocomposites, via electrospinning and solution-phase polymerization. The adsorption effect of the SPEEK toward NH₃ can facilitate the mass diffusion of NH₃ through the PPy layers, resulting in the enhanced sensing signals. On the basis of the SPEEK/PPy nanofibers, the sensors exhibit large gas responses, even when exposed to very low concentration of NH₃ (20 ppb) at room temperature.

  16. Single layer graphene protective gas barrier for copper photocathodes

    NASA Astrophysics Data System (ADS)

    Liu, Fangze; Moody, Nathan A.; Jensen, Kevin L.; Pavlenko, Vitaly; Narvaez Villarrubia, Claudia W.; Mohite, Aditya D.; Gupta, Gautam

    2017-01-01

    Photocathodes can benefit from a thin protection layer and attain long-term stability. Graphene is potentially a good candidate for such application. We report direct growth of single-layer graphene on single crystal Cu(110) photocathodes using chemical vapor deposition and the effective protection of copper photocathodes with graphene against degradation under atmospheric conditions. Due to the interaction and charge transfer between graphene and copper, the graphene-protected cathodes have 0.25 eV lower work function and 17% higher quantum efficiency at 250 nm compared with bare Cu cathodes. The graphene coating can protect copper photocathodes from degradation for more than 20 min in an exposure to 200 Torr of air. The validation of graphene-photocathode compatibility opens a new route to the lifetime-extension for photocathodes.

  17. Single molecular transistor as a superior gas sensor

    NASA Astrophysics Data System (ADS)

    Ray, S. J.

    2015-07-01

    Single Molecular Transistor (SMT) is known for its quantised nature of transport which can be used for sensing purposes. In this work, a SMT device prototype has been proposed for chemical sensing application, which is sensitive at the single molecular level. The operational methodology and performance have been investigated using first-principles calculations within a density functional theory framework. The charge stability diagram carries unique signature of the molecule present within the SMT and this property can be used to detect the presence of an individual molecule from a mixture of different molecules. Details about the possible experimental realisation of such a device has been discussed. The present approach provides a unique combination of very simple design with operation, perfect gate-island coupling, large temperature range of operation and extremely high detection sensitivity.

  18. Gas Sensors Based on Single-Arm Waveguide Interferometers

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey; Curley, Michael; Diggs, Darnell; Adamovsky, Grigory

    1998-01-01

    Various optical technologies can be implemented in chemical sensing. Sensitive, rugged, and compact systems will be more likely built using interferometric waveguide sensors. Currently existing sensors comprise dual-arm systems with external reference arm, dual-arm devices with internal reference arm such as integrated Mach-Zehnder interferometer, and single-arm systems which employ the interference between different waveguide modes. These latter ones are the most compact and rugged but still sensitive enough to monitor volatile pollutants such as NH3 coming out of industrial refrigerators and fertilizer plants and stocks, NO, NO2, SO2, emitted by industrial burning processes. Single-arm devices in planar waveguide configuration most frequently use two orthogonally polarized modes TE (sub i) and TM (sub i) of the same order i. Sensing effect is based on the difference in propagation conditions for the modes caused by the environment. However, dual-mode single-order interferometers still have relatively low sensitivity with respect to the environment related changes in the waveguide core because of small difference between propagation constants of TE (sub i) and TM (sub i) modes of the same order. Substantial sensitivity improvement without significant complication can be achieved for planar waveguide interferometers using modes of different orders with much greater difference between propagation constants.

  19. One-dimensional CdS/ZnO core/shell nanofibers via single-spinneret electrospinning: tunable morphology and efficient photocatalytic hydrogen production

    NASA Astrophysics Data System (ADS)

    Yang, Guorui; Yan, Wei; Zhang, Qian; Shen, Shaohua; Ding, Shujiang

    2013-11-01

    One dimensional core/shell nanostructures consisting of two different semiconductors with appropriate band alignment are promising for photocatalytic hydrogen production due to their efficient light harvesting and fast carrier transport. In this work, CdS/ZnO core/shell nanofibers were successfully synthesized by one-pot single-spinneret electrospinning. The ZnO layered structures (60 nm in thickness) were uniformly grown onto continuous CdS core fibers (220 nm in diameter and several micrometers in length). The as-fabricated CdS/ZnO core/shell nanofibers as nanoheterojunction photocatalysts exhibited excellent visible light photocatalytic activity and stability for hydrogen production. The possible formation mechanism of the CdS/ZnO core/shell nanofibers was also proposed based on the experimental observations. Moreover, the morphologies and components of the as-prepared nanofibers can be controlled easily by tuning the annealing temperature and Zn/Cd ratios of the precursor solution.One dimensional core/shell nanostructures consisting of two different semiconductors with appropriate band alignment are promising for photocatalytic hydrogen production due to their efficient light harvesting and fast carrier transport. In this work, CdS/ZnO core/shell nanofibers were successfully synthesized by one-pot single-spinneret electrospinning. The ZnO layered structures (60 nm in thickness) were uniformly grown onto continuous CdS core fibers (220 nm in diameter and several micrometers in length). The as-fabricated CdS/ZnO core/shell nanofibers as nanoheterojunction photocatalysts exhibited excellent visible light photocatalytic activity and stability for hydrogen production. The possible formation mechanism of the CdS/ZnO core/shell nanofibers was also proposed based on the experimental observations. Moreover, the morphologies and components of the as-prepared nanofibers can be controlled easily by tuning the annealing temperature and Zn/Cd ratios of the precursor solution

  20. Real-time imaging of methane gas leaks using a single-pixel camera.

    PubMed

    Gibson, Graham M; Sun, Baoqing; Edgar, Matthew P; Phillips, David B; Hempler, Nils; Maker, Gareth T; Malcolm, Graeme P A; Padgett, Miles J

    2017-02-20

    We demonstrate a camera which can image methane gas at video rates, using only a single-pixel detector and structured illumination. The light source is an infrared laser diode operating at 1.651μm tuned to an absorption line of methane gas. The light is structured using an addressable micromirror array to pattern the laser output with a sequence of Hadamard masks. The resulting backscattered light is recorded using a single-pixel InGaAs detector which provides a measure of the correlation between the projected patterns and the gas distribution in the scene. Knowledge of this correlation and the patterns allows an image to be reconstructed of the gas in the scene. For the application of locating gas leaks the frame rate of the camera is of primary importance, which in this case is inversely proportional to the square of the linear resolution. Here we demonstrate gas imaging at ~25 fps while using 256 mask patterns (corresponding to an image resolution of 16×16). To aid the task of locating the source of the gas emission, we overlay an upsampled and smoothed image of the low-resolution gas image onto a high-resolution color image of the scene, recorded using a standard CMOS camera. We demonstrate for an illumination of only 5mW across the field-of-view imaging of a methane gas leak of ~0.2 litres/minute from a distance of ~1 metre.

  1. Multiple shells in IRC+10216: shell properties

    NASA Astrophysics Data System (ADS)

    Mauron, N.; Huggins, P. J.

    2000-07-01

    We report on the properties of the multiple shells in the circumstellar envelope of IRC+10216, using deep optical imaging, including data from the Hubble Space Telescope. The intensity profiles confirm the presence of thin ( ~ 0farcs5 -3'' ec), limb-brightened shells in the envelope, seen in stellar and ambient Galactic light scattered by dust. The shells are spaced at irregular intervals of ~ 5'' ec-20'' ec, corresponding to time scales of 200-800 yr, although intervals as short as ~ 1'' ec (40 yr) are seen close to the star. The location of the main shells shows a good correlation with high-resolution, molecular line maps of the inner envelope, indicating that the dust and gas are well coupled. The shell/intershell density contrast is typically ~ 3, and we find that the shells form the dominant mass component of the circumstellar envelope. The shells exhibit important evolutionary effects: the thickness increases with increasing radius, with an effective dispersion velocity of 0.7 km s-1 and there is evidence for shell interactions. Despite the presence of bipolar structure close to the star, the global shell pattern favors a roughly isotropic, episodic mass loss mechanism, with a range of time scales. Based on observations made with the Canada-France-Hawaii telescope, operated by CNRS, NRCC and UH, and on dearchived observations made with the NASA/ESA Hubble Space Telescope, operated by AURA Inc., under NASA contract NAS5-26555

  2. Generalized gas-solid adsorption modeling: Single-component equilibria

    SciTech Connect

    Ladshaw, Austin; Yiacoumi, Sotira; Tsouris, Costas; DePaoli, David W.

    2015-01-07

    Over the last several decades, modeling of gas–solid adsorption at equilibrium has generally been accomplished through the use of isotherms such as the Freundlich, Langmuir, Tóth, and other similar models. While these models are relatively easy to adapt for describing experimental data, their simplicity limits their generality to be used with many different sets of data. This limitation forces engineers and scientists to test each different model in order to evaluate which one can best describe their data. Additionally, the parameters of these models all have a different physical interpretation, which may have an effect on how they can be further extended into kinetic, thermodynamic, and/or mass transfer models for engineering applications. Therefore, it is paramount to adopt not only a more general isotherm model, but also a concise methodology to reliably optimize for and obtain the parameters of that model. A model of particular interest is the Generalized Statistical Thermodynamic Adsorption (GSTA) isotherm. The GSTA isotherm has enormous flexibility, which could potentially be used to describe a variety of different adsorption systems, but utilizing this model can be fairly difficult due to that flexibility. To circumvent this complication, a comprehensive methodology and computer code has been developed that can perform a full equilibrium analysis of adsorption data for any gas-solid system using the GSTA model. The code has been developed in C/C++ and utilizes a Levenberg–Marquardt’s algorithm to handle the non-linear optimization of the model parameters. Since the GSTA model has an adjustable number of parameters, the code iteratively goes through all number of plausible parameters for each data set and then returns the best solution based on a set of scrutiny criteria. Data sets at different temperatures are analyzed serially and then linear correlations with temperature are made for the parameters of the model. The end result is a full set of

  3. Generalized gas-solid adsorption modeling: Single-component equilibria

    DOE PAGES

    Ladshaw, Austin; Yiacoumi, Sotira; Tsouris, Costas; ...

    2015-01-07

    Over the last several decades, modeling of gas–solid adsorption at equilibrium has generally been accomplished through the use of isotherms such as the Freundlich, Langmuir, Tóth, and other similar models. While these models are relatively easy to adapt for describing experimental data, their simplicity limits their generality to be used with many different sets of data. This limitation forces engineers and scientists to test each different model in order to evaluate which one can best describe their data. Additionally, the parameters of these models all have a different physical interpretation, which may have an effect on how they can bemore » further extended into kinetic, thermodynamic, and/or mass transfer models for engineering applications. Therefore, it is paramount to adopt not only a more general isotherm model, but also a concise methodology to reliably optimize for and obtain the parameters of that model. A model of particular interest is the Generalized Statistical Thermodynamic Adsorption (GSTA) isotherm. The GSTA isotherm has enormous flexibility, which could potentially be used to describe a variety of different adsorption systems, but utilizing this model can be fairly difficult due to that flexibility. To circumvent this complication, a comprehensive methodology and computer code has been developed that can perform a full equilibrium analysis of adsorption data for any gas-solid system using the GSTA model. The code has been developed in C/C++ and utilizes a Levenberg–Marquardt’s algorithm to handle the non-linear optimization of the model parameters. Since the GSTA model has an adjustable number of parameters, the code iteratively goes through all number of plausible parameters for each data set and then returns the best solution based on a set of scrutiny criteria. Data sets at different temperatures are analyzed serially and then linear correlations with temperature are made for the parameters of the model. The end result is a full set

  4. Structural Analysis Results of Thermal, Operating and Seismic Analysis for Hanford Single-Shell Tank Integrity - 12261

    SciTech Connect

    Pilli, Siva P.; Rinker, Michael W.

    2012-07-01

    Since Hanford's 149 Single-Shell Tanks (SSTs) are well beyond their design life, the U.S. Department of Energy has commissioned a state of the art engineering analysis to assess the structural integrity of the tanks to ensure that they are fit for service during the cleanup and closure phase. The structural integrity analysis has several challenging factors. There are four different tank sizes in various configurations that require analysis. Within each tank type there are different waste level and temperature histories, soil overburden depths, tank floor arrangements, riser sizes and locations, and other on-tank structures that need to be addressed. Furthermore, soil properties vary throughout the tank farms. This paper describes the structural integrity analysis that was performed for the SSTs using finite element models that incorporate the detailed design features of each tank type. The analysis was performed with two different models: an ANSYS static model for the Thermal and Operating Loads Analysis, and an ANSYS dynamic model for the seismic analysis. The TOLA analyses simulate the waste level and thermal history and it included a matrix of analysis cases that bounded the material property uncertainties. The TOLA also predicts the occurrence of concrete thermal degradations and cracking, reinforcement yielding, and soil plasticity. The seismic analysis matrix included uncertainty in waste properties, waste height and the soil modulus. In seismic analysis the tank concrete was modeled as a linear elastic material that was adjusted for the present day degraded conditions. Also, the soil was treated as a linear elastic material while special modeling techniques were used to avoid soil arching and achieve proper soil pressure on the tank walls. Seismic time histories in both the horizontal and vertical directions were applied to the seismic model. Structural demands from both Thermal and Operating Loads Analysis and seismic models were extracted in the form of

  5. Non-parametric representation and prediction of single- and multi-shell diffusion-weighted MRI data using Gaussian processes.

    PubMed

    Andersson, Jesper L R; Sotiropoulos, Stamatios N

    2015-11-15

    Diffusion MRI offers great potential in studying the human brain microstructure and connectivity. However, diffusion images are marred by technical problems, such as image distortions and spurious signal loss. Correcting for these problems is non-trivial and relies on having a mechanism that predicts what to expect. In this paper we describe a novel way to represent and make predictions about diffusion MRI data. It is based on a Gaussian process on one or several spheres similar to the Geostatistical method of "Kriging". We present a choice of covariance function that allows us to accurately predict the signal even from voxels with complex fibre patterns. For multi-shell data (multiple non-zero b-values) the covariance function extends across the shells which means that data from one shell is used when making predictions for another shell.

  6. Geochemical Characterization Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

    SciTech Connect

    Cantrell, Kirk J.; Brown, Christopher F.; Serne, R. Jeffrey; Krupka, Kenneth M.

    2008-01-07

    This data package discusses the geochemistry of vadose zone sediments beneath the single-shell tank (SST) farms at the U.S. Department of Energy’s (DOE’s) Hanford Site. The purpose of the report is to provide a review of the most recent and relevant geochemical information available for the vadose zone beneath the SST farms and the Integrated Disposal Facility (IDF).

  7. Core-shell self-assembly triggered via a thiol-disulfide exchange reaction for reduced glutathione detection and single cells monitoring

    PubMed Central

    Zhang, Zhen; Jiao, Yuting; Wang, Yuanyuan; Zhang, Shusheng

    2016-01-01

    A novel core-shell DNA self-assembly catalyzed by thiol-disulfide exchange reactions was proposed, which could realize GSH-initiated hybridization chain reaction (HCR) for signal amplification and molecules gathering. Significantly, these self-assembled products via electrostatic interaction could accumulate into prominent and clustered fluorescence-bright spots in single cancer cells for reduced glutathione monitoring, which will effectively drive cell monitoring into a new era. PMID:27412605

  8. Development and testing of single-shell tank waste retrieval technologies: Milestone M-45-01 summary report

    SciTech Connect

    Shen, E.J.

    1994-08-01

    This report summarizes the activities undertaken to develop single-shell tank (SST) waste retrieval technology and complete scale-model testing. Completion of these activities fulfills the commitment of Milestone M-45-01 of the Hanford Federal Facility Agreement and Consent Order (the Tri-Party Agreement). Initial activities included engineering studies that compiled and evaluated data on all known retrieval technologies. Based on selection criteria incorporating regulatory, safety, and operational issues, several technologies were selected for further evaluation and testing. The testing ranged from small-scale, bench-top evaluations of individual technologies to full-scale integrated tests of multiple subsystems operating concurrently as a system using simulated wastes. The current baseline retrieval method for SSTs is hydraulic sluicing. This method has been used successfully in the past to recover waste from SSTs. Variations of this hydraulic or ``past practice`` sluicing may be used to retrieve the waste from the majority of the SSTs. To minimize the potential for releases to the soil, arm-based retrieval systems may be used to recover waste from tanks that are known or suspected to have leaked. Both hydraulic sluicing and arm-based retrieval will be demonstrated in the first SST. Hydraulic sluicing is expected to retrieve most of the waste, and arm-based retrieval will retrieve wastes that remain after sluicing. Subsequent tanks will be retrieved by either hydraulic sluicing or arm-based methods, but not both. The method will be determined by waste characterization, tank integrity (leak status), and presence of in-tank hardware. Currently, it is assumed that approximately 75% of all SSTs will be retrieved by hydraulic sluicing and the remaining tanks by arm-based methods.

  9. PERFORMANCE ASSESSMENT TO SUPPORT CLOSURE OF SINGLE-SHELL TANK WASTE MANAGEMENT AREA C AT THE HANFORD SITE

    SciTech Connect

    BERGERON MP

    2010-01-14

    Current proposed regulatory agreements (Consent Decree) at the Hanford Site call for closure of the Single-Shell Tank (SST) Waste Management Area (WMA) C in the year 2019. WMA C is part of the SST system in 200 East area ofthe Hanford Site and is one of the first tank farm areas built in mid-1940s. In order to close WMA C, both tank and facility closure activities and corrective actions associated with existing soil and groundwater contamination must be performed. Remedial activities for WMA C and corrective actions for soils and groundwater within that system will be supported by various types of risk assessments and interim performance assessments (PA). The U.S. Department of Energy, Office of River Protection (DOE-ORP) and the State ofWashington Department of Ecology (Ecology) are sponsoring a series of working sessions with regulators and stakeholders to solicit input and to obtain a common understanding concerning the scope, methods, and data to be used in the planned risk assessments and PAs to support closure of WMA C. In addition to DOE-ORP and Ecology staff and contractors, working session members include representatives from the U.S. Enviromnental Protection Agency, the U.S. Nuclear Regulatory Commission (NRC), interested tribal nations, other stakeholders groups, and members of the interested public. NRC staff involvement in the working sessions is as a technical resource to assess whether required waste determinations by DOE for waste incidental to reprocessing are based on sound technical assumptions, analyses, and conclusions relative to applicable incidental waste criteria.

  10. Refinement of Modeling Techniques for the Structural Evaluation of Hanford Single-Shell Nuclear Waste Storage Tanks

    SciTech Connect

    Karri, Naveen K.; Rinker, Michael W.; Johnson, Kenneth I.; Bapanapalli, Satish K.

    2012-11-10

    ABSTRACT Several tanks at the Hanford Site (in Washington State, USA) belong to the first generation of underground nuclear waste storage tanks known as single shell tanks (SSTs). These tanks were constructed between 1943 and 1964 and are well beyond their design life. This article discusses the structural analysis approach and modeling challenges encountered during the ongoing analysis of record (AOR) for evaluating the structural integrity of the SSTs. There are several geometrical and material nonlinearities and uncertainties to be dealt with while performing the modern finite element analysis of these tanks. The analysis takes into account the temperature history of the tanks and allowable mechanical operating loads of these tanks for proper estimation of creep strains and thermal degradation of material properties. The loads prescribed in the AOR models also include anticipated loads that these tanks may see during waste retrieval and closure. Due to uncertainty in a number of inputs to the models, sensitivity studies were conducted to address questions related to the boundary conditions to realistically or conservatively represent the influence of surrounding tanks in a tank farm, the influence of backfill excavation slope, the extent of backfill and the total extent of undisturbed soil surrounding the backfill. Because of the limited availability of data on the thermal and operating history for many of the individual tanks, some of the data was assumed or interpolated. However, the models developed for the analysis of record represent the bounding scenarios and include the loading conditions that the tanks were subjected to or anticipated. The modeling refinement techniques followed in the AOR resulted in conservative estimates for force and moment demands at various sections in the concrete tanks. This article discusses the modeling aspects related to Type-II and Type-III SSTs. The modeling techniques, methodology and evaluation criteria developed for

  11. Shell forming system

    NASA Technical Reports Server (NTRS)

    Kendall, Jr., James M. (Inventor); Wang, Taylor G. (Inventor); Elleman, Daniel D. (Inventor)

    1990-01-01

    Hollow shells of high uniformity are formed by emitting liquid through an outer nozzle and gas through an inner nozzle, to form a hollow extrusion, by flowing the gas at a velocity between about 1.3 and 10 times the liquid velocity. The natural breakup rate of the extrusion can be increased to decrease shell size by applying periodic perturbations to one of the materials prior to exiting the nozzles, to a nozzle, or to the extrusion.

  12. Yolk-shell nanocrystal@ZIF-8 nanostructures for gas-phase heterogeneous catalysis with selectivity control.

    PubMed

    Kuo, Chun-Hong; Tang, Yang; Chou, Lien-Yang; Sneed, Brian T; Brodsky, Casey N; Zhao, Zipeng; Tsung, Chia-Kuang

    2012-09-05

    A general synthetic strategy for yolk-shell nanocrystal@ZIF-8 nanostructures has been developed. The yolk-shell nanostructures possess the functions of nanoparticle cores, microporous shells, and a cavity in between, which offer great potential in heterogeneous catalysis. The synthetic strategy involved first coating the nanocrystal cores with a layer of Cu(2)O as the sacrificial template and then a layer of polycrystalline ZIF-8. The clean Cu(2)O surface assists in the formation of the ZIF-8 coating layer and is etched off spontaneously and simultaneously during this process. The yolk-shell nanostructures were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and nitrogen adsorption. To study the catalytic behavior, hydrogenations of ethylene, cyclohexene, and cyclooctene as model reactions were carried out over the Pd@ZIF-8 catalysts. The microporous ZIF-8 shell provides excellent molecular-size selectivity. The results show high activity for the ethylene and cyclohexene hydrogenations but not in the cyclooctene hydrogenation. Different activation energies for cyclohexene hydrogenation were obtained for nanostructures with and without the cavity in between the core and the shell. This demonstrates the importance of controlling the cavity because of its influence on the catalysis.

  13. Controllable synthesis of recyclable core-shell γ-Fe2O3@SnO2 hollow nanoparticles with enhanced photocatalytic and gas sensing properties.

    PubMed

    Zhang, Shaofeng; Ren, Feng; Wu, Wei; Zhou, Juan; Xiao, Xiangheng; Sun, Lingling; Liu, Ying; Jiang, Changzhong

    2013-06-07

    Composite materials containing different components with well-defined structures may cooperatively enhance their performance and extend their applications. In this work, core-shell γ-Fe2O3@SnO2 hollow nanoparticles (NPs) were synthesized by a low-cost and environmentally friendly seed-mediated hydrothermal method. Firstly, the γ-Fe2O3 hollow NPs were synthesized by a template-free method. Then they were used as the cores for the growth of SnO2 shells. The thickness of the shell can be simply tailored by controlling the reaction time. Various techniques, including SEM, XRD, TEM and HRTEM, were employed to investigate the morphology, structure and formation process of the special core-shell hollow structures. The combination of magnetic semiconductor (γ-Fe2O3) and wide band-gap semiconductor (SnO2) endowed them with great potential to be used as recyclable photocatalysts. Experiments on photo-degradation of Rhodamin B (RhB) dye in the presence of the samples showed that the hybrid structures possessed higher photocatalytic activities than the monomer structures of SnO2 and γ-Fe2O3 materials indicating a strong coupling enhancement effect between the wide and narrow band-gap semiconductors. Moreover, the gas sensing tests of the γ-Fe2O3@SnO2 hollow NPs revealed that the samples exhibited fast response and recovery rates, which enable them to be promising materials for gas sensors.

  14. Single-shot gas-phase thermometry by time-to-frequency mapping of coherence dephasing.

    PubMed

    Yue, Orin; Bremer, Marshall T; Pestov, Dmitry; Gord, James R; Roy, Sukesh; Dantus, Marcos

    2012-08-09

    We demonstrate a single-beam coherent anti-Stokes Raman scattering (CARS) technique for gas-phase thermometry that assesses the species-specific local gas temperature by single-shot time-to-frequency mapping of Raman-coherence dephasing. The proof-of-principle experiments are performed with air in a temperature-controlled gas cell. Impulsive excitation of molecular vibrations by an ultrashort pump/Stokes pulse is followed by multipulse probing of the 2330 cm(-1) Raman transition of N(2). This sequence of colored probe pulses, delayed in time with respect to each other and corresponding to three isolated spectral bands, imprints the coherence dephasing onto the measured CARS spectrum. For calibration purposes, the dephasing rates are recorded at various gas temperatures, and the relationship is fitted to a linear regression. The calibration data are then used to determine the gas temperature and are shown to provide better than 15 K accuracy. The described approach is insensitive to pulse energy fluctuations and can, in principle, gauge the temperature of multiple chemical species in a single laser shot, which is deemed particularly valuable for temperature profiling of reacting flows in gas-turbine combustors.

  15. Gas depletion through single gas bubble diffusive growth and its effect on subsequent bubbles

    NASA Astrophysics Data System (ADS)

    Moreno Soto, Alvaro; Prosperetti, Andrea; Lohse, Detlef; van der Meer, Devaraj; Physics of Fluid Group Collaboration; MCEC Netherlands CenterMultiscale Catalytic Energy Conversion Collaboration

    2016-11-01

    In weakly supersaturated mixtures, bubbles are known to grow quasi-statically as diffusion-driven mass transfer governs the process. In the final stage of the evolution, before detachment, there is an enhancement of mass transfer, which changes from diffusion to natural convection. Once the bubble detaches, it leaves behind a gas-depleted area. The diffusive mass transfer towards that region cannot compensate for the amount of gas which is taken away by the bubble. Consequently, the consecutive bubble will grow in an environment which contains less gas than for the previous one. This reduces the local supersaturation of the mixture around the nucleation site, leading to a reduced bubble growth rate. We present quantitative experimental data on this effect and the theoretical model for depletion during the bubble growth rate. This work was supported by the Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), an NWO Gravitation programme funded by the Ministry of Education, Culture and Science of the government of the Netherlands.

  16. Effects of gas molecules on an ultraviolet photodetector with a single-layer titania nanosheet

    NASA Astrophysics Data System (ADS)

    Matsuzaki, Koji; Taniguchi, Takaaki; Matsumoto, Yasumichi; Hara, Masahiro

    2015-01-01

    We have demonstrated an ultraviolet photodetector fabricated from a chemically exfoliated single-layer titania nanosheet. The photocurrent showed a clear on/off switching with a short time response under periodic pulsed illuminations. Suppressions of the photocurrent due to environmental gas molecules were observed under medium vacuum region (1.0-300 Pa). The observation even in inert nitrogen gas implies an enhancement of annihilations of photo-excited carriers due to collisions of inert gas molecules on the surface-sensitive titania nanosheet.

  17. Single-particle spectral density of a Bose gas in the two-fluid hydrodynamic regime

    SciTech Connect

    Arahata, Emiko; Nikuni, Tetsuro; Griffin, Allan

    2011-11-15

    In Bose superfluids, the single-particle Green's function can be directly related to the superfluid velocity-velocity correlation function in the hydrodynamic regime. An explicit expression for the single-particle spectral density was originally written down by Hohenberg and Martin in 1965, starting from the two-fluid equations for a superfluid. We give a simple derivation of their results. Using these results, we calculate the relative weights of first and second sound modes in the single-particle spectral density as a function of temperature in a uniform Bose gas. We show that the second sound mode makes a dominant contribution to the single-particle spectrum in a relatively high-temperature region. We also discuss the possibility of experimental observation of the second sound mode in a Bose gas by photoemission spectroscopy.

  18. An Initial Evaluation Of Characterization And Closure Options For Underground Pipelines Within A Hanford Site Single-Shell Tank Farm

    SciTech Connect

    Badden, Janet W.; Connelly, Michael P.; Seeley, Paul N.; Hendrickson, Michelle L.

    2013-01-10

    The Hanford Site includes 149 single-shell tanks, organized in 12 'tank farms,' with contents managed as high-level mixed waste. The Hanford Federal Facility Agreement and Consent Order requires that one tank farm, the Waste Management Area C, be closed by June 30, 2019. A challenge to this project is the disposition and closure of Waste Management Area C underground pipelines. Waste Management Area C contains nearly seven miles of pipelines and 200 separate pipe segments. The pipelines were taken out of service decades ago and contain unknown volumes and concentrations of tank waste residuals from past operations. To understand the scope of activities that may be required for these pipelines, an evaluation was performed. The purpose of the evaluation was to identify what, if any, characterization methods and/or closure actions may be implemented at Waste Management Area C for closure of Waste Management Area C by 2019. Physical and analytical data do not exist for Waste Management Area C pipeline waste residuals. To develop estimates of residual volumes and inventories of contamination, an extensive search of available information on pipelines was conducted. The search included evaluating historical operation and occurrence records, physical attributes, schematics and drawings, and contaminant inventories associated with the process history of plutonium separations facilities and waste separations and stabilization operations. Scoping analyses of impacts to human health and the environment using three separate methodologies were then developed based on the waste residual estimates. All analyses resulted in preliminary assessments, indicating that pipeline waste residuals presented a comparably low long-term impact to groundwater with respect to soil, tank and other ancillary equipment residuals, but exceeded Washington State cleanup requirement values. In addition to performing the impact analyses, the assessment evaluated available sampling technologies and

  19. Impacts from Partial Removal of Decommissioned Oil and Gas Platforms on Fish Biomass and Production on the Remaining Platform Structure and Surrounding Shell Mounds.

    PubMed

    Claisse, Jeremy T; Pondella, Daniel J; Love, Milton; Zahn, Laurel A; Williams, Chelsea M; Bull, Ann S

    2015-01-01

    When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth) or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on all but one platform off the coast of California. On average 80% of fish biomass and 86% of secondary fish production would be retained after partial removal, with above 90% retention expected for both metrics on many platforms. Partial removal would likely result in the loss of fish biomass and production for species typically found residing in the shallow portions of the platform structure. However, these fishes generally represent a small proportion of the fishes associated with these platforms. More characteristic of platform fauna are the primarily deeper-dwelling rockfishes (genus Sebastes). "Shell mounds" are biogenic reefs that surround some of these platforms resulting from an accumulation of mollusk shells that have fallen from the shallow areas of the platforms mostly above the depth of partial removal. We found that shell mounds are moderately productive fish habitats, similar to or greater than natural rocky reefs in the region at comparable depths. The complexity and areal extent of these biogenic habitats, and the associated fish biomass and production, will likely be reduced after either partial or complete platform removal. Habitat augmentation by placing the partially removed platform superstructure or some other additional habitat enrichment material (e.g., rock boulders) on the seafloor adjacent to the base of partially removed platforms provides additional options to enhance fish production, potentially mitigating reductions in shell mound habitat.

  20. Impacts from Partial Removal of Decommissioned Oil and Gas Platforms on Fish Biomass and Production on the Remaining Platform Structure and Surrounding Shell Mounds

    PubMed Central

    Claisse, Jeremy T.; Pondella, Daniel J.; Love, Milton; Zahn, Laurel A.; Williams, Chelsea M.; Bull, Ann S.

    2015-01-01

    When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth) or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on all but one platform off the coast of California. On average 80% of fish biomass and 86% of secondary fish production would be retained after partial removal, with above 90% retention expected for both metrics on many platforms. Partial removal would likely result in the loss of fish biomass and production for species typically found residing in the shallow portions of the platform structure. However, these fishes generally represent a small proportion of the fishes associated with these platforms. More characteristic of platform fauna are the primarily deeper-dwelling rockfishes (genus Sebastes). “Shell mounds” are biogenic reefs that surround some of these platforms resulting from an accumulation of mollusk shells that have fallen from the shallow areas of the platforms mostly above the depth of partial removal. We found that shell mounds are moderately productive fish habitats, similar to or greater than natural rocky reefs in the region at comparable depths. The complexity and areal extent of these biogenic habitats, and the associated fish biomass and production, will likely be reduced after either partial or complete platform removal. Habitat augmentation by placing the partially removed platform superstructure or some other additional habitat enrichment material (e.g., rock boulders) on the seafloor adjacent to the base of partially removed platforms provides additional options to enhance fish production, potentially mitigating reductions in shell mound habitat. PMID:26332384

  1. Single ZnO Nanowire-Based Gas Sensors to Detect Low Concentrations of Hydrogen

    PubMed Central

    Cardoza-Contreras, Marlene N.; Romo-Herrera, José M.; Ríos, Luis A.; García-Gutiérrez, R.; Zepeda, T. A.; Contreras, Oscar E.

    2015-01-01

    Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum probe in situ in a dual-beam scanning electron microscope-focused ion beam with a manipulator and a gas injection system in/column. The electrical response of the manufactured devices shows response times up to 29 s for a 121 ppm of H2 pulse, with a variation in the nanowire resistance appreciable at room temperature and at 373.15 K of approximately 8% and 14% respectively, showing that ZnO nanowires are good candidates to detect low concentrations of H2. PMID:26690158

  2. Single ZnO Nanowire-Based Gas Sensors to Detect Low Concentrations of Hydrogen.

    PubMed

    Cardoza-Contreras, Marlene N; Romo-Herrera, José M; Ríos, Luis A; García-Gutiérrez, R; Zepeda, T A; Contreras, Oscar E

    2015-12-04

    Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum probe in situ in a dual-beam scanning electron microscope-focused ion beam with a manipulator and a gas injection system in/column. The electrical response of the manufactured devices shows response times up to 29 s for a 121 ppm of H₂ pulse, with a variation in the nanowire resistance appreciable at room temperature and at 373.15 K of approximately 8% and 14% respectively, showing that ZnO nanowires are good candidates to detect low concentrations of H₂.

  3. Electrowetting-on-dielectrics for manipulation of oil drops and gas bubbles in aqueous-shell compound drops.

    PubMed

    Li, Jiang; Wang, Yixuan; Chen, Haosheng; Wan, Jiandi

    2014-11-21

    We present the manipulation of oil, organic and gaseous chemicals by electrowetting-on-dielectric (EWOD) technology using aqueous-shell compound drops. We demonstrate that the transport and coalescence of viscous oil drops, the reaction of bromine with styrene in benzene solution, and the reaction of red blood cells with carbon monoxide bubbles can be accomplished using this method.

  4. Gas field ion source current stability for trimer and single atom terminated W(111) tips

    SciTech Connect

    Urban, Radovan; Wolkow, Robert A.; Pitters, Jason L.

    2012-06-25

    Tungsten W(111) oriented trimer-terminated tips as well as single atom tips, fabricated by a gas and field assisted etching and evaporation process, were investigated with a view to scanning ion microscopy and ion beam writing applications. In particular, ion current stability was studied for helium and neon imaging gases. Large ion current fluctuations from individual atomic sites were observed when a trimer-terminated tip was used for the creation of neon ion beam. However, neon ion current was stable when a single atom tip was employed. No such current oscillations were observed for either a trimer or a single atom tip when imaged with helium.

  5. Growth of single wall carbon nanotubes using PECVD technique: An efficient chemiresistor gas sensor

    NASA Astrophysics Data System (ADS)

    Lone, Mohd Yaseen; Kumar, Avshish; Husain, Samina; Zulfequar, M.; Harsh; Husain, Mushahid

    2017-03-01

    In this work, the uniform and vertically aligned single wall carbon nanotubes (SWCNTs) have been grown on Iron (Fe) deposited Silicon (Si) substrate by plasma enhanced chemical vapor deposition (PECVD) technique at very low temperature of 550 °C. The as-grown samples of SWCNTS were characterized by field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM) and Raman spectrometer. SWCNT based chemiresistor gas sensing device was fabricated by making the proper gold contacts on the as-grown SWCNTs. The electrical conductance and sensor response of grown SWCNTs have been investigated. The fabricated SWCNT sensor was exposed to ammonia (NH3) gas at 200 ppm in a self assembled apparatus. The sensor response was measured at room temperature which was discussed in terms of adsorption of NH3 gas molecules on the surface of SWCNTs. The achieved results are used to develope a miniaturized gas sensor device for monitoring and control of environment pollutants.

  6. Micro Gas Preconcentrator Made of a Film of Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Takada, Shuji; Nakai, Takashi; Thurakitseree, Theerapol; Shiomi, Junichiro; Maruyama, Shigeo; Takagi, Hideki; Shuzo, Masaki; Delaunay, Jean-Jacques; Yamada, Ichiro

    The development of micro gas preconcentrators is crucial for the realization of miniaturized gas chromatography (micro-GC) systems which are expected to open up new applications such as breath analysis. One of the major problems with the reduction in the preconcentrator size by miniaturization is the availability of a sorbent material having high enough concentration factor. Single-walled carbon nanotubes (SWNTs) are one of the promising materials for high adsorption capacity. In this report, a gas preconcentrator having a depth of 40 μm and a volume of 1 μL was microfabricated. The synthesized SWNT films with a thickness of 30 μm were embedded in the micro gas preconcentrators by using the hot water-assisted detachment method. The small size of the fabricated micro gas preconcentrator and the use of SWNTs as the adsorbent material allow for achieving a concentration factor as high as 16000 for 2 ppm octane. This concentration factor value is the highest reported to date for micro gas preconcentrators and sufficient for micro-GC detectors to concentrate trace analytes of interest for breath analysis. It is concluded that micro gas preconcentrators using SWNTs as the adsorbent material have great potential to concentrate compounds.

  7. Biexciton quantum yield heterogeneities in single CdSe(CdS) core(shell) nanocrystals and its correlation to exciton blinking

    PubMed Central

    Zhao, Jing; Chen, Ou; Strasfeld, David B.

    2012-01-01

    We explore biexciton (BX) non-radiative recombination processes in single semiconductor nanocrystals (NCs) using confocal fluorescence microscopy and second-order photon intensity correlation. More specifically, we measure the photoluminescence blinking and BX quantum yields (QYs), and study the correlation between these two measurements for single core(shell) CdSe(CdS) nanocrystals (NCs). We find that NCs with a high “on” time fraction are significantly more likely to have a high BX QY than NCs with a low “on” fraction, even though the BX QYs of NCs with a high “on” fraction vary dramatically. The BX QYs of single NCs are also weakly dependent upon excitation wavelength. The weak correlation between exciton “on” fractions and BX QYs suggests that multiple recombination processes are involved in the BX recombination. To explain our results, we propose a model that combines both trapping and an Auger mechanism for BX recombination. PMID:22871126

  8. Remote sensing of high temperature H2O CO2 CO mixture with a correlated k-distribution fictitious gas method and the single-mixture gas assumption

    NASA Astrophysics Data System (ADS)

    Caliot, C.; Le Maoult, Y.; El Hafi, M.; Flamant, G.

    2006-11-01

    Infrared spectra of high temperature H2O CO2 CO mixtures are calculated using narrow band models in order to simulate hot jet signature at long distance. The correlated k-distribution with fictitious gas (CKFG) approach generally gives accurate data in such situations (especially for long atmospheric paths) but results in long computation time in cases involving mixtures of gases. This time may be reduced if the mixture is treated as a single gas (single-mixture gas assumption, SMG). Thus the lines of the single-mixture gas are assigned to the fictitious gases. In this study, the accuracy of two narrow band models is evaluated. The first narrow band model considers one single-mixture gas and no fictitious gas (CK-SMG) whereas the second model accounts for one single-mixture gas and three fictitious gases (CKFG-SMG). Both narrow band models are compared with reference spectra calculated with a line-by-line (LBL) approach. As expected, the narrow band accuracy is improved by the fictitious gas (FG) assumption particularly when long atmospheric paths are involved. Concerning the SMG assumption, it may lead to an underestimation of about 10% depending on the variation of the gas mixture composition ratio. Nevertheless, in most of realistic situations the SMG assumption results in negligible errors and may be used for remote sensing of plume signature.

  9. Computational analysis of coupled fluid, heat, and mass transport in ferrocyanide single-shell tanks: FY 1994 interim report. Ferrocyanide Tank Safety Project

    SciTech Connect

    McGrail, B.P.

    1994-11-01

    A computer modeling study was conducted to determine whether natural convection processes in single-shell tanks containing ferrocyanide wastes could generate localized precipitation zones that significantly concentrate the major heat-generating radionuclide, {sup 137}Cs. A computer code was developed that simulates coupled fluid, heat, and single-species mass transport on a regular, orthogonal finite-difference grid. The analysis showed that development of a ``hot spot`` is critically dependent on the temperature dependence for the solubility of Cs{sub 2}NiFe(CN){sub 6} or CsNaNiFe(CN){sub 6}. For the normal case, where solubility increases with increasing temperature, the net effect of fluid flow, heat, and mass transport is to disperse any local zones of high heat generation rate. As a result, hot spots cannot physically develop for this case. However, assuming a retrograde solubility dependence, the simulations indicate the formation of localized deposition zones that concentrate the {sup 137}Cs near the bottom center of the tank where the temperatures are highest. Recent experimental studies suggest that Cs{sub 2}NiFe(CN){sub 6}(c) does not exhibit retrograde solubility over the temperature range 25{degree}C to 90{degree}C and NaOH concentrations to 5 M. Assuming these preliminary results are confirmed, no natural mass transport process exists for generating a hot spot in the ferrocyanide single-shell tanks.

  10. Radiative energy and momentum transfer for various spherical shapes: A single sphere, a bubble, a spherical shell, and a coated sphere

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Ghanekar, Alok

    2015-02-01

    We use fluctuational electrodynamics to determine spectral emissivity and van der Waals contribution to surface energy for various spherical shapes, such as a sphere, a bubble, a spherical shell, and a coated sphere, in a homogeneous and isotropic medium. The dyadic Green's function formalism of radiative energy and fluctuation-induced van der Waals stress for different spherical configurations has been developed. We show (1) emission spectra of micro- and nano-sized single and coated spheres display several emissivity sharp peaks as the size of object reduces and (2) surface energy becomes size dependent due to van der Waals phenomena when size of object is reduced to a nanoscopic length scale.

  11. Radiative energy and momentum transfer for various spherical shapes: A single sphere, a bubble, a spherical shell, and a coated sphere

    SciTech Connect

    Zheng, Yi Ghanekar, Alok

    2015-02-14

    We use fluctuational electrodynamics to determine spectral emissivity and van der Waals contribution to surface energy for various spherical shapes, such as a sphere, a bubble, a spherical shell, and a coated sphere, in a homogeneous and isotropic medium. The dyadic Green's function formalism of radiative energy and fluctuation-induced van der Waals stress for different spherical configurations has been developed. We show (1) emission spectra of micro- and nano-sized single and coated spheres display several emissivity sharp peaks as the size of object reduces and (2) surface energy becomes size dependent due to van der Waals phenomena when size of object is reduced to a nanoscopic length scale.

  12. DEVELOPMENT OF THE BULK VITRIFICATION TREATMENT PROCESS FOR THE LOW ACTIVITY FRACTION OF HANFORD SINGLE SHELL TANK WASTES

    SciTech Connect

    Thompson, L.E.; Lowery, P.S.; Arrowsmith, H.W.; Snyder, T.; McElroy, J.L.

    2003-02-27

    AMEC Earth & Environmental, Inc. and RWE NUKEM Corporation have teamed to develop and apply a waste pre-treatment and bulk vitrification process for low activity waste (LAW) from Hanford Single Shell Tanks (SSTs). The pretreatment and bulk vitrification process utilizes technologies that have been successfully deployed to remediate both radioactive and chemically hazardous wastes at nuclear power plants, DOE sites, and commercial waste sites in the US and abroad. The process represents an integrated systems approach. The proposed AMEC/NUKEM process follow the extraction and initial segregation activities applied to the tank wastes carried out by others. The first stage of the process will utilize NUKEM's concentrate dryer (CD) system to concentrate the liquid waste stream. The concentrate will then be mixed with soil or glass formers and loaded into refractory-lined steel containers for bulk vitrification treatment using AMEC's In-Container Vitrification (ICV) process. Following the vitrification step, a lid will be placed on the container of cooled, solidified vitrified waste, and the container transported to the disposal site. The container serves as the melter vessel, the transport container and the disposal container. AMEC and NUKEM participated in the Mission Acceleration Initiative Workshop held in Richland, Washington in April 2000 [1]. An objective of the workshop was to identify selected technologies that could be combined into viable treatment options for treatment of the LAW fraction from selected Hanford waste tanks. AMEC's ICV process combined with NUKEM's CD system and other remote operating capabilities were presented as an integrated solution. The Team's proposed process received some of the highest ratings from the Workshop's review panel. The proposed approach compliments the Hanford Waste Treatment Plant (WTP) by reducing the amount of waste that the WTP would have to process. When combined with the capabilities of the WTP, the proposed approach

  13. Refinement of Modeling Techniques for the Structural Evaluation of Hanford Single-Shell Nuclear Waste Storage Tanks

    SciTech Connect

    Karri, Naveen K.; Rinker, Michael W.; Johnson, Kenneth I.; Bapanapalli, Satish K.

    2012-03-01

    Abstract: A total of 149 tanks out of 177 at the Hanford Site (in Washington State, USA) belong to the first generation of underground nuclear waste storage tanks known as single shell tanks (SSTs). These tanks were constructed between 1943 and 1964 and are well beyond their design life. All the SSTs had been removed from active service by November 1980 and have been later interim stabilized by removing the pumpable liquids. The remaining waste in the tanks is in the form of salt cake and sludge awaiting r permanent disposal.. The evaluation of the structural integrity of these tanks is of utmost importance not only for the continued safe storage of the waste until waste retrieval and closure, but also to assure safe retrieval and closure operations. This article discusses the structural analysis approach, modeling challenges and issues encountered during the ongoing analysis of record (AOR) for evaluating the structural integrity of the SSTs. There are several geometrical and material nonlinearities and uncertainties to be dealt with while performing the modern finite element analysis of these tanks. Several studies were conducted to refine the models in order to minimize modeling artifacts introduced by soil arching, boundary effects, concrete cracking, and concrete-soil interface behavior. The analysis takes into account the temperature history of the tanks and allowable mechanical operating loads of these tanks for proper estimation of creep strains and thermal degradation of material properties. The loads imposed in the AOR models also include anticipated loads that these tanks may see during waste retrieval and closure. Due to uncertainty in a number of inputs to the models, sensitivity studies were conducted to address questions related to the boundary conditions to realistically or conservatively represent the influence of surrounding tanks in a tank farm, the influence of backfill excavation slope, the extent of backfill and the total extent of undisturbed

  14. Hi shells, supershells, shell-like objects, and ''worms''

    SciTech Connect

    Heiles, C.

    1984-08-01

    We present photographic representations of the combination of two Hi surveys, so as to eliminate the survey boundaries at Vertical BarbVertical Bar = 10/sup 0/. We also present high-contrast photographs for particular velocities to exhibit weak Hi features. All of these photographs were used to prepare a new list of Hi shells, supershells, and shell-like objects. We discuss the structure of three shell-like objects that are associated with high-velocity gas, and with gas at all velocities that is associated with radio continuum loops I, II, and III. We use spatial filtering to find wiggly gas filaments: ''worms'': crawling away from the galactic plane in the inner Galaxy. The ''worms'' are probably parts of shells that are open at the top; such shells should be good sources of hot gas for the galactic halo.

  15. Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Romero-Hermida, M. I.; Romero-Enrique, J. M.; Morales-Flórez, V.; Esquivias, L.

    2016-08-01

    Adsorption of flue gases by single-wall carbon nanotubes (SWCNT) has been studied by means of Monte Carlo simulations. The flue gas is modeled as a ternary mixture of N2, CO2, and O2, emulating realistic compositions of the emissions from power plants. The adsorbed flue gas is in equilibrium with a bulk gas characterized by temperature T, pressure p, and mixture composition. We have considered different SWCNTs with different chiralities and diameters in a range between 7 and 20 Å. Our results show that the CO2 adsorption properties depend mainly on the bulk flue gas thermodynamic conditions and the SWCNT diameter. Narrow SWCNTs with diameter around 7 Å show high CO2 adsorption capacity and selectivity, but they decrease abruptly as the SWCNT diameter is increased. For wide SWCNT, CO2 adsorption capacity and selectivity, much smaller in value than for the narrow case, decrease mildly with the SWCNT diameter. In the intermediate range of SWCNT diameters, the CO2 adsorption properties may show a peculiar behavior, which depend strongly on the bulk flue gas conditions. Thus, for high bulk CO2 concentrations and low temperatures, the CO2 adsorption capacity remains high in a wide range of SWCNT diameters, although the corresponding selectivity is moderate. We correlate these findings with the microscopic structure of the adsorbed gas inside the SWCNTs.

  16. Borehole Data Package for Well 299-E33-44 at Single-Shell Tank Waste Management Area B-BX-BY

    SciTech Connect

    DG Horton; SM Narbutovskih

    1999-03-23

    One new Resource Conservation and Recovery Act (RCRA) groundwater monitoring well was installed during September 1998 at the single-shell tank farm Waste Management Area (WMA) B-BX-BY. The well is 299-E33-44 and is located east of the BY single-shell tank farm. The well is a new upgradient monitoring well drilled in support of the groundwater assessment program at WMA B-BX-BY. This document is a compilation of information on the drilling and construction well development pump installation, and sediment testing and analyses applicable to well 299-E33-44. Appendix A contains copies of the geologist's log, the Well Construction Summary Report and Well Summary Sheet (as-built diagram); Appendix B contains results of Laboratory analyses completed on samples of sediment from the well and Appendix C contains geophysical logs. An aquifer test (slug test) was done in the well after well completion. Results from the aquifer test will be published elsewhere. Additional documentation concerning well construction is on file with Bechtel Hanford Inc., Richland, Washington.

  17. Simultaneous, single-pulse, synchrotron x-ray imaging and diffraction under gas gun loading

    SciTech Connect

    Fan, D.; Huang, J. W.; Zeng, X. L.; Li, Y.; E, J. C.; Huang, J. Y.; Sun, T.; Fezzaa, K.; Wang, Z.; Luo, S. N.

    2016-05-23

    We develop a mini gas gun system for simultaneous, single-pulse, x-ray diffraction and imaging under high strain-rate loading at the beamline 32-ID of the Advanced Photon Source. In order to increase the reciprocal space covered by a small-area detector, a conventional target chamber is split into two chambers: a narrowed measurement chamber and a relief chamber. The gas gun impact is synchronized with synchrotron x-ray pulses and high-speed cameras. Depending on a camera’s capability, multiframe imaging and diffraction can be achieved. The proof-of-principle experiments are performed on single-crystal sapphire. The diffraction spots and images during impact are analyzed to quantify lattice deformation and fracture; diffraction peak broadening is largely caused by fracture-induced strain inhomogeneity. Finally, our results demonstrate the potential of such multiscale measurements for revealing and understanding high strain-rate phenomena at dynamic extremes.

  18. Inflammable gas mixture detection with a single catalytic sensor based on the electric field effect.

    PubMed

    Tong, Ziyuan; Tong, Min-Ming; Meng, Wen; Li, Meng

    2014-04-08

    This paper introduces a new way to analyze mixtures of inflammable gases with a single catalytic sensor. The analysis technology was based on a new finding that an electric field on the catalytic sensor can change the output sensitivity of the sensor. The analysis of mixed inflammable gases results from processing the output signals obtained by adjusting the electric field parameter of the catalytic sensor. For the signal process, we designed a group of equations based on the heat balance of catalytic sensor expressing the relationship between the output signals and the concentration of gases. With these equations and the outputs of different electric fields, the gas concentration in a mixture could be calculated. In experiments, a mixture of methane, butane and ethane was analyzed by this new method, and the results showed that the concentration of each gas in the mixture could be detected with a single catalytic sensor, and the maximum relative error was less than 5%.

  19. A single-atom sharp iridium tip as an emitter of gas field ion sources

    NASA Astrophysics Data System (ADS)

    Kuo, Hong-Shi; Hwang, Ing-Shouh; Fu, Tsu-Yi; Hwang, Ying-Siang; Lu, Yi-Hsien; Lin, Chun-Yueh; Hou, Jin-Long; Tsong, Tien T.

    2009-08-01

    We report a reliable method for preparing a pure Ir single-atom tip by thermal treatment in oxygen. The atomic structure of the tip apex and its ion emission characteristics are investigated with field ion microscopy. We have shown that the Ir single-atom tip can be a good field ion emitter, capable of emitting a variety of gas ion beams, such as He+, H2+, N2+, and O2+, with high brightness and stability. In addition, this tip can easily be maintained and regenerated in vacuum, ensuring it has sufficient lifetime for practical applications.

  20. Single-pulse broad-band rotational CARS thermometry of cold N2 gas

    NASA Technical Reports Server (NTRS)

    Chang, R. K.; Murphy, D. V.

    1981-01-01

    Coherent anti Stokes Raman scattering (CARS) from the pure rotational Raman lines of N2 was employed to measure the instantaneous (10 nsec) rotational temperature of the gas at room temperature and below. An entire rotational CARS spectrum was generated by a single laser pulse using a broad bandwidth dye laser and was recorded on an optical multichannel analyzer. A best fit temperature obtained for individual experimental spectra by comparison with calculated spectra. Good agreement between CARS temperatures and thermocouple temperatures was observed.

  1. Dynamics of a single trapped ion immersed in a buffer gas

    NASA Astrophysics Data System (ADS)

    Höltkemeier, Bastian; Weckesser, Pascal; López-Carrera, Henry; Weidemüller, Matthias

    2016-12-01

    We provide a comprehensive theoretical framework for describing the dynamics of a single trapped ion interacting with a neutral buffer gas, thus extending our previous studies on buffer-gas cooling of ions beyond the critical mass ratio [B. Höltkemeier et al., Phys. Rev. Lett. 116, 233003 (2016), 10.1103/PhysRevLett.116.233003]. By transforming the collisional processes into a frame, where the ion's micromotion is assigned to the buffer-gas atoms, our model allows us to investigate the influence of nonhomogeneous buffer-gas configurations as well as higher multipole orders of the radio-frequency trap in great detail. Depending on the neutral-to-ion mass ratio, three regimes of sympathetic cooling are identified which are characterized by the form of the ion's energy distribution in equilibrium. We provide analytic expressions and numerical simulations of the ion's energy distribution, spatial profile, and cooling rates for these different regimes. Based on these findings, a method for actively decreasing the ion's energy by reducing the spatial expansion of the buffer gas arises (forced sympathetic cooling).

  2. SINGLE-SHELL TANK INTEGRITY PROJECT ANALYSIS OF RECORD-PRELIMINARY MODELING PLAN FOR THERMAL AND OPERATING LOADS

    SciTech Connect

    RAST RS; RINKER MW; BAPANAALLI SK; DEIBLER JE; GUZMAN-LEONG CE; JOHNSON KI; KARRI NK; PILLI SP; SANBORN SE

    2010-10-22

    This document is a Phase I deliverable for the Single-Shell Tank Analysis of Record effort. This document is not the Analysis of Record. The intent of this document is to guide the Phase II detailed modeling effort. Preliminary finite element models for each of the tank types were developed and different case studies were performed on one or more of these tank types. Case studies evaluated include thermal loading, waste level variation, the sensitivity of boundary effects (soil radial extent), excavation slope or run to rise ratio, soil stratigraphic (property and layer thickness) variation at different farm locations, and concrete material property variation and their degradation under thermal loads. The preliminary analysis document reviews and preliminary modeling analysis results are reported herein. In addition, this report provides recommendations for the next phase of the SST AOR project, SST detailed modeling. Efforts and results discussed in this report do not include seismic modeling as seismic modeling is covered by a separate report. The combined results of both static and seismic models are required to complete this effort. The SST AOR project supports the US Department of Energy's (DOE) Office of River Protection (ORP) mission for obtaining a better understanding of the structural integrity of Hanford's SSTs. The 149 SSTs, with six different geometries, have experienced a range of operating histories which would require a large number of unique analyses to fully characterize their individual structural integrity. Preliminary modeling evaluations were conducted to determine the number of analyses required for adequate bounding of each of the SST tank types in the Detailed Modeling Phase of the SST AOR Project. The preliminary modeling was conducted in conjunction with the Evaluation Criteria report, Johnson et al. (2010). Reviews of existing documents were conducted at the initial stage of preliminary modeling. These reviews guided the topics that were

  3. Solar-Blind Avalanche Photodetector Based On Single ZnO-Ga₂O₃ Core-Shell Microwire.

    PubMed

    Zhao, Bin; Wang, Fei; Chen, Hongyu; Wang, Yunpeng; Jiang, Mingming; Fang, Xiaosheng; Zhao, Dongxu

    2015-06-10

    High-performance solar-blind (200-280 nm) avalanche photodetectors (APDs) were fabricated based on highly crystallized ZnO-Ga2O3 core-shell microwires. The responsivity can reach up to 1.3 × 10(3) A/W under -6 V bias. Moreover, the corresponding detectivity was as high as 9.91 × 10(14) cm·Hz(1/2)/W. The device also showed a fast response, with a rise time shorter than 20 μs and a decay time of 42 μs. The quality of the detectors in solar-blind waveband is comparable to or even higher than that of commercial Si APD (APD120A2 from Thorlabs Inc.), with a responsivity ∼8 A/W, detectivity ∼10(12) cm·Hz(1/2)/W, and response time ∼20 ns. The high performance of this APD make it highly suitable for practical applications as solar-blind photodetectors, and this core-shell microstructure heterojunction design method would provide a new approach for realizing an APD device.

  4. Nonthermal Plasma Synthesis of Core/Shell Quantum Dots: Strained Ge/Si Nanocrystals.

    PubMed

    Hunter, Katharine I; Held, Jacob T; Mkhoyan, K Andre; Kortshagen, Uwe R

    2017-03-08

    In this work, we present an all-gas-phase approach for the synthesis of quantum-confined core/shell nanocrystals (NCs) as a promising alternative to traditional solution-based methods. Spherical quantum dots (QDs) are grown using a single-stage flow-through nonthermal plasma, yielding monodisperse NCs, with a concentric core/shell structure confirmed by electron microscopy. The in-flight negative charging of the NCs by plasma electrons keeps the NC cores separated during shell growth. The success of this gas-phase approach is demonstrated here through the study of Ge/Si core/shell QDs. We find that the epitaxial growth of a Si shell on the Ge QD core compressively strains the Ge lattice and affords the ability to manipulate the Ge band structure by modulation of the core and shell dimensions. This all-gas-phase approach to core/shell QD synthesis offers an effective method to produce high-quality heterostructured NCs with control over the core and shell dimensions.

  5. Kinematics of Ultra-high-velocity Gas in the Expanding Molecular Shell Adjacent to the W44 Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Yamada, Masaya; Oka, Tomoharu; Takekawa, Shunya; Iwata, Yuhei; Tsujimoto, Shiho; Tokuyama, Sekito; Furusawa, Maiko; Tanabe, Keisuke; Nomura, Mariko

    2017-01-01

    We mapped the ultra-high-velocity feature (the “Bullet”) detected in the expanding molecular shell associated with the W44 supernova remnant using the Nobeyama Radio Observatory 45 m telescope and the Atacama Submillimeter Telescope Experiment 10 m telescope. The Bullet clearly appears in the CO J = 1–0, CO J = 3–2, CO J = 4–3, and HCO+ J = 1–0 maps with a compact appearance (0.5 × 0.8 pc2) and an extremely broad-velocity width (ΔV ≃ 100 km s‑1). The line intensities indicate that the Bullet has a higher density and temperature than those in the expanding molecular shell. The kinetic energy of the Bullet amounts to 1048.0 erg, which is approximately 1.5 orders of magnitude greater than the kinetic energy shared to the small solid angle of it. Two possible formation scenarios with an inactive isolated black hole are presented.

  6. A novel single frequency stabilized Fabry-Perot laser diode at 1590 nm for gas sensing

    NASA Astrophysics Data System (ADS)

    Weldon, Vincent; Boylan, Karl; Corbett, Brian; McDonald, David; O'Gorman, James

    2002-09-01

    A novel single frequency stabilized Fabry-Perot (SFP) laser diode with an emission wavelength of λ=1590 nm for H 2S gas sensing is reported. Sculpting of the multi-mode spectral distribution of a FP laser to achieve single frequency emission is carried out using post growth photolitographic processing of the device. The resulting longitudinal-mode controlled FP laser has a stabilized single frequency emission with a side mode suppression ratio (SMSR) of 40 dB. The application of this device to spectroscopic based H 2S sensing is demonstrated by targeting absorption lines in the wavelength range 1588≤ λ≤1591 nm. Using wavelength modulation spectroscopy (WMS), a low detection limit of 120 ppm.m.Hz -1/2 was estimated while targeting the absorption line at 1590.08 nm. These initial results demonstrate the potential of the stabilized FP laser diode at this wavelength as a tunable, single frequency source for spectroscopic based gas sensing.

  7. Combining hard and soft magnetism into a single core-shell nanoparticle to achieve both hyperthermia and image contrast

    PubMed Central

    Yang, Qiuhong; Gong, Maogang; Cai, Shuang; Zhang, Ti; Douglas, Justin T; Chikan, Viktor; Davies, Neal M; Lee, Phil; Choi, In-Young; Ren, Shenqiang; Forrest, M Laird

    2015-01-01

    Background A biocompatible core/shell structured magnetic nanoparticles (MNPs) was developed to mediate simultaneous cancer therapy and imaging. Methods & results A 22-nm MNP was first synthesized via magnetically coupling hard (FePt) and soft (Fe3O4) materials to produce high relative energy transfer. Colloidal stability of the FePt@Fe3O4 MNPs was achieved through surface modification with silane-polyethylene glycol (PEG). Intravenous administration of PEG-MNPs into tumor-bearing mice resulted in a sustained particle accumulation in the tumor region, and the tumor burden of treated mice was a third that of the mice in control groups 2 weeks after a local hyperthermia treatment. In vivo magnetic resonance imaging exhibited enhanced T2 contrast in the tumor region. Conclusion This work has demonstrated the feasibility of cancer theranostics with PEG-MNPs. PMID:26606855

  8. Multi-shell effective interactions

    NASA Astrophysics Data System (ADS)

    Tsunoda, Naofumi; Takayanagi, Kazuo; Hjorth-Jensen, Morten; Otsuka, Takaharu

    2014-02-01

    Background: Effective interactions, either derived from microscopic theories or based on fitting selected properties of nuclei in specific mass regions, are widely used inputs to shell-model studies of nuclei. The commonly used unperturbed basis functions are given by the harmonic oscillator. Until recently, most shell-model calculations have been confined to a single oscillator shell like the sd shell or the pf shell. Recent interest in nuclei away from the stability line requires, however, larger shell-model spaces. Because the derivation of microscopic effective interactions has been limited to degenerate models spaces, there are both conceptual and practical limits to present shell-model calculations that utilize such interactions. Purpose: The aim of this work is to present a novel microscopic method to calculate effective nucleon-nucleon interactions for the nuclear shell model. Its main difference from existing theories is that it can be applied not only to degenerate model spaces but also to nondegenerate model spaces. This has important consequences, in particular for intershell matrix elements of effective interactions. Methods: The formalism is presented in the form of a many-body perturbation theory based on the recently developed extended Kuo-Krenciglowa method. Our method enables us to microscopically construct effective interactions not only in one oscillator shell but also for several oscillator shells. Results: We present numerical results using effective interactions within (i) a single oscillator shell (a so-called degenerate model space) like the sd shell or the pf shell and (ii) two major shells (nondegenerate model space) like the sdf7p3 shell or the pfg9 shell. We also present energy levels of several nuclei that have two valence nucleons on top of a given closed-shell core. Conclusions: Our results show that the present method works excellently in shell-model spaces that comprise several oscillator shells, as well as in a single oscillator

  9. Economics of Condensing Gas Furnaces and Water Heaters Potential in Residential Single Family Homes

    SciTech Connect

    Lekov, Alex; Franco, Victor; Meyers, Steve

    2010-05-14

    Residential space and water heating accounts for over 90percent of total residential primary gas consumption in the United States. Condensing space and water heating equipment are 10-30percent more energy-efficient than conventional space and water heating. Currently, condensing gas furnaces represent 40 percent of shipments and are common in the Northern U.S. market. Meanwhile, manufacturers are planning to develop condensing gas storage water heaters to qualify for Energy Star? certification. Consumers, installers, and builders who make decisions about installing space and water heating equipment generally do not perform an analysis to assess the economic impacts of different combinations and efficiencies of space and water heating equipment. Thus, equipment is often installed without taking into consideration the potential life-cycle economic and energy savings of installing space and water heating equipment combinations. Drawing on previous and current analysis conducted for the United States Department of Energy rulemaking on amended standards for furnaces and water heaters, this paper evaluates the extent to which condensing equipment can provide life-cycle cost-effectiveness in a representative sample of single family American homes. The economic analyses indicate that significant energy savings and consumer benefits may result from large-scale introduction of condensing water heaters combined with condensing furnaces in U.S. residential single-family housing, particularly in the Northern region. The analyses also shows that important benefits may be overlooked when policy analysts evaluate the impact of space and water heating equipment separately.

  10. Relation between single very-long-period pulses and volcanic gas emissions at Mt. Asama, Japan

    NASA Astrophysics Data System (ADS)

    Kazahaya, Ryunosuke; Mori, Toshiya; Takeo, Minoru; Ohminato, Takao; Urabe, Taku; Maeda, Yuta

    2011-06-01

    Multiple volcanic observations conducted at Mt. Asama, Japan, provide evidence of a link between single very-long-period (VLP) seismic pulses and volcanic gas emissions. SO2 flux measurements were conducted on 2 June 2009, when Mt. Asama was producing ash-free eruptions with VLP pulses. Gas bursts from a vent at the crater bottom following the VLP pulses provided an excellent opportunity to examine the relation directly. The SO2 emission for each eruption was calculated by integrating high temporal SO2 flux data obtained by the SO2 imaging system and subtracting the contribution from quiescent degassing from fumaroles around the crater bottom. A seismic moment of VLP pulse was estimated by the waveform inversion. We observed seven eruptions and obtained the proportional relation between VLP pulse moment and SO2 emission. The relation determined is consistent with the VLP source model; these observational results are the first report of a quantitative comparison between single VLP pulse moment and volcanic gas emission.

  11. The Measurable Effects of Germanium Loaded into the Pusher of a Pushered Single Shell Capsule Designed for the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Tipton, Robert; Baker, Kevin; Casey, Daniel; Dewald, Eduard; Graziani, Frank; MacLaren, Steve; Nikroo, Abass; Pino, Jesse; Ralph, Joe; Remington, Bruce; Sacks, Ryan; Salmonson, Jay; Smalyuk, Vladimir

    2016-10-01

    Germanium loaded pushered single shells (PSS) have been designed as a vehicle to study the effects of turbulent mixing between the DT fuel and a pusher which is not fully ionized. This is intended as a surrogate for the high-Z mixing expected in future double-shell ignition capsules. These PSS experiments will be diagnosed by loading deuterium along with the germanium into the GDP pusher and filling the capsule with a mixture of tritium and hydrogen. In such CD mix experiments, the measured number of DT neutrons along with the inferred ion temperature from the time-of-flight thermal broadening provides detailed information about the annular mixing of the fuel and the pusher. This paper will compare the expected DT mix signals from capsules loaded with germanium to control capsules fired without any germanium. Leading turbulent mix models predict the germanium loaded capsules and no-germanium control capsules will produce significantly different results. This work was performed under the auspices of the U.S. Department of Energy by LLNL under contract DE-AC52-07NA27344,LLNS, LLC.

  12. Linear and nonlinear optical properties of a single dopant in strained AlAs/GaAs spherical core/shell quantum dots

    NASA Astrophysics Data System (ADS)

    El Haouari, M.; Talbi, A.; Feddi, E.; El Ghazi, H.; Oukerroum, A.; Dujardin, F.

    2017-01-01

    The hydrostatic pressure influence on the binding energy and on the optical properties (linear and third nonlinear) associated to the 1 s - 1 p intersubband transition of single dopant in a AlAs / GaAs spherical core/shell structure is investigated. The combined effects of the problem variables such as the core and shell sizes, the donor position in the structure and the pressure dependence of the physical parameters of the material have been analyzed. Our calculations are performed in the framework of the effective mass approximation and the energies are obtained by using a variational method. The results show that the linear and nonlinear parts of the absorption coefficient and the refractive index associated to the intersubband 1 s - 1 p transition undergo important changes. There are several interesting results to point out such as the shift of the absorption coefficients and refractive index to high values of photon energy. Another significant result is that the donor position considerably affects the optical properties and their corresponding amplitude.

  13. Selective and uniform growth of single-wall carbon nanotubes (SWCNTs) for gas sensing application

    NASA Astrophysics Data System (ADS)

    Alvi, M. A.; Al-Ghamdi, A. A.; Khan, Shamshad A.

    2017-03-01

    In the present work, we have synthesized uniformly distributed single-wall carbon nanotube (SWCNT) networks with a selective diameter suitable for gas sensing device. The SWCNT networks have been synthesized on 2-nm-thick iron (Fe) catalyst-coated silicon (Si) substrates by Plasma-Enhanced Chemical Vapor Deposition (PECVD). The as-grown SWCNTs were characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy techniques. Using SWCNT network, the sensitivity of ammonia (NH3) gases/vapors was recognized by their surface adsorption and desorption responses. The response curve was observed from the SWCNT network, which is due to a change in the resistance upon exposure to NH3 gas.

  14. A single-step route for large-scale synthesis of core-shell palladium@platinum dendritic nanocrystals/reduced graphene oxide with enhanced electrocatalytic properties

    NASA Astrophysics Data System (ADS)

    Liu, Qi; Xu, Yan-Ru; Wang, Ai-Jun; Feng, Jiu-Ju

    2016-01-01

    In this report, a facile, seed-less and single-step method is developed for large-scale synthesis of core-shell Pd@Pt dendritic nanocrystals anchored on reduced graphene oxide (Pd@Pt DNC/rGO) under mild conditions. Poly(ethylene oxide) is employed as a structure-directing and stabilizing agent. Compared with commercial Pt/C (20 wt%) and Pd/C (20 wt%) catalysts, the as-obtained nanocomposite has large electrochemically active surface area (114.15 m2 gmetal-1), and shows superior catalytic activity and stability with the mass activities of 1210.0 and 1128.5 mAmgmetal-1 for methanol and ethanol oxidation, respectively. The improved catalytic activity is mainly the consequence of the synergistic effects between Pd and Pt of the dendritic structures, as well as rGO as a support.

  15. Evanescent-wave pumped room-temperature single-mode GaAs/AlGaAs core-shell nanowire lasers

    SciTech Connect

    Wei, Wei; Zhang, Xia Ren, Xiaomin; Liu, Yange Wang, Zhi

    2014-06-02

    Evanescent-wave pumped room-temperature single-mode GaAs/AlGaAs core-shell nanowire lasers are proposed and demonstrated. The nanowires are axially excited by evanescent wave outside a microfiber with a diameter about 10 μm via a ns-pulse laser. The lasing emission with a low effective threshold less than 90 nJ is achieved at 868.62 nm along with a linewidth of ∼1.8 nm. Moreover, multiple lasing lines in a wavelength range from 852.56 nm to 882.48 nm are observed. The mechanism of diverse lasing wavelengths is revealed. Furthermore, the proposed GaAs/AlGaAs nanowire laser has advantages such as simple structure, easy to operate, and controllable lasing wavelength, tending to be practical in optical communications and integrated photonic circuits.

  16. Development of a multi-functional scarifier dislodger with an integral pneumatic conveyance retrieval system for single-shell tank remediation. FY93 summary report

    SciTech Connect

    Bamberger, J.A.; McKinnon, M.A.; Alberts, D.A.; Steele, D.E.; Crowe, C.T.

    1994-10-01

    The Underground Storage Tank Integrated Demonstration (UST-ID) is evaluating several hydraulic dislodger concepts and retrieval technologies to develop specifications for system that can retrieve wastes from single-shell tanks. Each of the dislodgers will be evaluated sequentially to determine its ability to fracture and dislodge various waste simulants such as salt cake, sludge, and viscous liquid. The retrieval methods will be evaluated to determine their ability to convey this dislodged material from the tank. This report describes on-going research that commenced in FY93 to develop specifications for a scarifier dislodger coupled with a pneumatic conveyance retrieval system. The scarifier development is described in Section 3; pneumatic conveyance development is described in Section 4. Preliminary system specifications are listed in Section 5. FY94 plans are summarized in Section 6.

  17. Results of Phase I groundwater quality assessment for single-shell tank waste management Area S-SX at the Hanford Site

    SciTech Connect

    Johnson, V.G.; Chou, C.J.

    1998-01-01

    Pacific Northwest National Laboratory (PNNL) conducted a Phase I, Resource Conservation and Recovery Act of 1976 (RCRA) groundwater quality assessment for the Richland Field Office of the U.S. Department of Energy (DOE-RL), in accordance with the Federal Facility Compliance Agreement. The purpose of the investigation was to determine if the Single-Shell Tank Waste Management Area (WMA) S-SX has impacted groundwater quality. The WMA is located in the southern portion of the 200 West Area of the Hanford Site and consists of the 241-S and 241-SX tank farms and ancillary waste systems. The unit is regulated under RCRA interim-status regulations (40 CFR 265, Subpart F) and was placed in assessment groundwater monitoring (40 CFR 265.93 [d]) in August 1996 because of elevated specific conductance and technetium-99, a non-RCRA co-contaminant, in downgradient monitoring wells. Major findings of the assessment are summarized below: (1) Distribution patterns for radionuclides and RCRA/dangerous waste constituents indicate WMA S-SX has contributed to groundwater contamination observed in downgradient monitoring wells. (2) Drinking water standards for nitrate and technetium-99 are currently exceeded in one RCRA-compliant well (299-W22-46) located at the southeastern comer of the SX tank farm. (3) Technetium-99, nitrate, and chromium concentrations in downgradient well 299-W22-46 (the well with the highest current concentrations) appear to be declining after reaching maximum concentrations in May 1997. (4) Cesium-137 and strontium-90, major constituents of concern in single-shell tank waste, were not detected in any of the RCRA-compliant wells in the WMA network, including the well with the highest current technetium-99 concentrations (299-W22-46). (5) Low but detectable strontium-90 and cesium-137 were found in one old well (2-W23-7), located inside and between the S and SX tank farms.

  18. Microsecond fiber laser pumped, single-frequency optical parametric oscillator for trace gas detection.

    PubMed

    Barria, Jessica Barrientos; Roux, Sophie; Dherbecourt, Jean-Baptiste; Raybaut, Myriam; Melkonian, Jean-Michel; Godard, Antoine; Lefebvre, Michel

    2013-07-01

    We report on the first microsecond doubly resonant optical parametric oscillator (OPO). It is based on a nested cavity OPO architecture allowing single longitudinal mode operation and low oscillation threshold (few microjoule). The combination with a master oscillator-power amplifier fiber pump laser provides a versatile optical source widely tunable in the 3.3-3.5 μm range with an adjustable pulse repetition rate (from 40 to 100 kHz), high duty cycle (~10(-2)) and mean power (up to 25 mW in the idler beam). The potential for trace gas sensing applications is demonstrated through photoacoustic detection of atmospheric methane.

  19. Behavior of bubbles in glassmelts. III - Dissolution and growth of a rising bubble containing a single gas

    NASA Technical Reports Server (NTRS)

    Onorato, P. I. K.; Weinberg, M. C.; Uhlmann, D. R.

    1981-01-01

    Finite difference solutions of the mass transport equations governing the dissolution (growth) of a rising gas bubble, containing a single gas, in a glassmelt were obtained. These solutions were compared with those obtained from an approximate procedure for a range of the controlling parameters. Applications were made to describe various aspects of O2 and CO2 gas-bubble behavior in a soda-lime-silicate melt.

  20. Application of Gas Dynamical Friction for Planetesimals. I. Evolution of Single Planetesimals

    NASA Astrophysics Data System (ADS)

    Grishin, Evgeni; Perets, Hagai B.

    2015-09-01

    The growth of small planetesimals into large planetary embryos occurs far before the dispersal of the gas from the protoplanetary disk. The planetesimal-gaseous disk interactions give rise to migration and orbital evolution of the planetesimals/planets. Small planetesimals are dominated by aerodynamic gas drag. Large protoplanets, m˜ 0.1{M}\\oplus , are dominated by type I migration differential torque. There is an additional mass range m˜ {10}21-{10}25 {{g}} of intermediate-mass planetesimals (IMPs), where gravitational interactions with the disk dominate over aerodynamic gas drag, but for which such interactions were typically neglected. Here, we model these interactions using the gas dynamical friction (GDF) approach, previously used to study the disk-planet interactions at the planetary mass range. We find the critical size where GDF dominates over gas drag, and then we study the implications of GDF on single IMPs. We find that planetesimals with small inclinations rapidly become co-planar. Eccentric orbits circularize within a few Myr, provided the the planetesimal mass is large, m≳ {10}23 {{g}}, and that the initial eccentricity is low, e≲ 0.1. Planetesimals of higher masses, m˜ {10}24-{10}25 {{g}}, inspiral on a timescale of a few Myr, leading to an embryonic migration to the inner disk. This can lead to an overabundance of rocky material (in the form of IMPs) in the inner protoplanetary disk (\\lt 1 {AU}) and induce rapid planetary growth. This can explain the origin of super-Earth planets. In addition, GDF damps the velocities of IMPs, thereby cooling the planetesimal disk and affecting its collisional evolution through quenching the effects of viscous stirring by the large bodies.

  1. Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Yoosefian, Mehdi

    2017-01-01

    Density functional studies on the adsorption behavior of nitrous oxide (N2O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N2O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N2O onto CNT, the horizontal adsorption with Eads = -0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N2O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N2O were investigated. Adsorption of N2O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N2O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N2O sensors.

  2. Bayesian Estimation of Fugitive Methane Point Source Emission Rates from a SingleDownwind High-Frequency Gas Sensor

    EPA Science Inventory

    Bayesian Estimation of Fugitive Methane Point Source Emission Rates from a Single Downwind High-Frequency Gas Sensor With the tremendous advances in onshore oil and gas exploration and production (E&P) capability comes the realization that new tools are needed to support env...

  3. Development of a peristaltic gas micropump with a single chamber and multiple electrodes

    NASA Astrophysics Data System (ADS)

    Lee, K. S.; Kim, B.; Shannon, M. A.

    2013-09-01

    This paper reports on the development of a multi-electrode electrostatically driven peristaltic gas micropump. The micropump consists of a single chamber and a flexible diaphragm with a multi-electrode pattern. The single-chamber design is divided into smaller cells by the electrodes; the characteristic operating frequency of the micropump increases as the number of electrodes increases. The flow rate is also observed to increase to maximum before decreasing for larger numbers of electrodes. Whereas the maximum flow rate of a 4-electrode micropump is about 40 µl min-1 at 14 Hz, the maximum flow rate of the 16-electrode micropump is about 250 µl min-1 at 1400 Hz and that of the 32-electrode micropump is 150 µl min-1 at 4000 Hz.

  4. Intramolecularly Coordinated Gallium Sulfides: Suitable Single Source Precursors for GaS Thin Films.

    PubMed

    Řičica, Tomáš; Světlík, Tomáš; Dostál, Libor; Růžička, Aleš; Růžička, Květoslav; Beneš, Ludvík; Němec, Petr; Bouška, Marek; Jambor, Roman

    2016-12-23

    Our studies have been focused on the synthesis of N→Ga coordinated organogallium sulfides [L(1) Ga(μ-S)]3 (1) and [L(2) Ga(μ-S)]2 (2) containing either N,C,N- or C,N-chelating ligands L(1) or L(2) (L(1) is {2,6-(Me2 NCH2 )2 C6 H3 }(-) and L(2) is {2-(Et2 NCH2 )-4,6-tBu2 -C6 H2 }(-) ). As the result of the different ligands, compounds 1 and 2 differ mutually in their structure. To change the Ga/S ratio, unusually N→Ga coordinated organogallium tetrasulfide L(1) Ga(κ(2) -S4 ) (3) was prepared and the unprecedented complex [{2-[CH{(CH2 )3 CH3 }(μ-OH)]-6-CH2 NMe2 }C6 H3 ]GaS (4) was also isolated as the minor by-product of the reaction. Compounds 1-3 were further studied as potential single-source precursors for amorphous GaS thin film deposition by spin-coating.

  5. Simultaneous, single-pulse, synchrotron x-ray imaging and diffraction under gas gun loading

    DOE PAGES

    Fan, D.; Huang, J. W.; Zeng, X. L.; ...

    2016-05-23

    We develop a mini gas gun system for simultaneous, single-pulse, x-ray diffraction and imaging under high strain-rate loading at the beamline 32-ID of the Advanced Photon Source. In order to increase the reciprocal space covered by a small-area detector, a conventional target chamber is split into two chambers: a narrowed measurement chamber and a relief chamber. The gas gun impact is synchronized with synchrotron x-ray pulses and high-speed cameras. Depending on a camera’s capability, multiframe imaging and diffraction can be achieved. The proof-of-principle experiments are performed on single-crystal sapphire. The diffraction spots and images during impact are analyzed to quantifymore » lattice deformation and fracture; diffraction peak broadening is largely caused by fracture-induced strain inhomogeneity. Finally, our results demonstrate the potential of such multiscale measurements for revealing and understanding high strain-rate phenomena at dynamic extremes.« less

  6. Development of Metal-impregnated Single Walled Carbon Nanotubes for Toxic Gas Contaminant Control in Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Pisharody, Suresh A.; Fisher, John W.; Wignarajah, K.

    2002-01-01

    The success of physico-chemical waste processing and resource recovery technologies for life support application depends partly on the ability of gas clean-up systems to efficiently remove trace contaminants generated during the process with minimal use of expendables. Carbon nanotubes promise superior performance over conventional approaches to gas clean-up due to their ability to direct the selective uptake of gaseous species based on their controlled pore size, high surface area, ordered chemical structure that allows functionalization and their effectiveness also as catalyst support materials for toxic gas conversion. We present results and findings from a preliminary study on the effectiveness of metal impregnated single walled nanotubes as catalyst/catalyst support materials for toxic gas contaminate control. The study included the purification of single walled nanotubes, the catalyst impregnation of the purified nanotubes, the experimental characterization of the surface properties of purified single walled nanotubes and the characterization of physisorption and chemisorption of uptake molecules.

  7. Determination of and evidence for non-core-shell structure of particles containing black carbon using the Single-Particle Soot Photometer (SP2)

    NASA Astrophysics Data System (ADS)

    Sedlacek, Arthur J., III; Lewis, Ernie R.; Kleinman, Lawrence; Xu, Jianzhong; Zhang, Qi

    2012-03-01

    The large uncertainty associated with black carbon (BC) direct forcing is due, in part, to the dependence of light absorption of BC-containing particles on the position of the BC within the particle. It is predicted that this absorption will be greatest for an idealized core-shell configuration in which the BC is a sphere at the center of the particle whereas much less absorption should be observed for particles in which the BC is located near or on the surface. Such microphysical information on BC-containing particles has previously been provided only by labor-intensive microscopy techniques, thus often requiring that climate modelers make assumptions about the location of the BC within the particle that are based more on mathematical simplicity than physical reality. The present paper describes a novel analysis method that utilizes the temporal behavior of the scattering and incandescence signals from individual particles containing refractory BC (rBC) measured by the Single-Particle Soot Photometer (SP2) to distinguish particles with rBC near the surface from those that have structures more closely resembling the core-shell configuration. This approach permits collection of a high-time-resolution data set of the fraction of rBC-containing particles with rBC near the surface. By application of this method to a plume containing tracers for biomass burning, it was determined that this fraction was greater than 60%. Such a data set will not only provide previously unavailable information to the climate modeling community, allowing greater accuracy in calculating rBC radiative forcing, but also will yield insight into aerosol processes.

  8. Ultra-small, uniform, and single bcc-phased Fe(x)Co(1-x)/graphitic shell nanocrystals for T1 magnetic resonance imaging contrast agents.

    PubMed

    Choi, In Ae; Li, Yan; Kim, Da Jeong; Pal, Mou; Cho, Jee-Hyun; Lee, Kyujoon; Jung, Myung-Hwa; Lee, Chulhyun; Seo, Won Seok

    2013-01-01

    We have synthesized ultra-small and uniform Fe(x)Co(1-x)/graphitic carbon shell (Fe(x)Co(1-x)/GC) nanocrystals (x=0.13, 0.36, 0.42, 0.50, 0.56, and 0.62, respectively) with average diameters of <4 nm by thermal decomposition of metal precursors in approximately 60 nm MCM-41 and methane CVD. The composition of the Fe(x)Co(1-x)/GC nanocrystals can be tuned by changing the Fe:Co ratios of the metal precursors. The Fe(x)Co(1-x)/GC nanocrystals show superparamagnetic properties at room temperature. The Fe(0.50)Co(0.50)/GC, Fe(0.56)Co(0.44)/GC, and Fe(0.62)Co(0.38)/GC nanocrystals have a single bcc FeCo structure, whereas the Fe(0.13)Co(0.87)/GC, Fe(0.36)Co(0.64)/GC, and Fe(0.42)Co(0.58)/GC nanocrystals have a mixed structure of bcc FeCo and fcc Co. The single bcc-phased Fe(x)Co(1-x)/GC nanocrystals functionalized with phospholipid-poly(ethylene glycol) (PL-PEG) in phosphate buffered saline (PBS) are demonstrated to be excellent T(1) MRI contrast agents.

  9. Gas Exchange and Phytoluminography of Single Red Kidney Bean Leaves during Periods of Induced Stomatal Oscillations

    PubMed Central

    Ellenson, James L.; Raba, Richard M.

    1983-01-01

    This report examines the capabilities of a new approach to the study of gas exchange and electron transport properties of single, intact leaves. The method combines conventional aspects of analysis with an image intensification system that records the spatial distribution of delayed light emission (DLE) over single leaf surfaces. The combined system was used to investigate physiological perturbations induced by exposure of single leaves of Phaseolus vulgaris cv `California Light Red' to a combination of SO2 (0.5 microliters per liter) and ozone (0.1 microliters per liter). Exposure of one-half of a leaf to this combination induced DLE and stomatal oscillations, but only in the half of the leaf exposed to the combined gases. Examination of phytoluminographs taken during these oscillations revealed distinct leaf patches where the greatest changes in DLE intensity occurred. This phenomenon is interpreted to be evidence that control of stomatal activity of intact plant leaves occurs within discrete leaf areas defined within the vascular network. Images Fig. 6 PMID:16662989

  10. Kinematics of the Ultra-High-Velocity Gas in the Expanding Molecular Shell Adjacent to the W44 Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Yamada, Masaya; Oka, Tomoharu; Tanaka, Kunihiko; Nomura, Mariko; Takekawa, Shunya; Iwata, Yuhei; Tokuyama, Sekito; Tanabe, Keisuke; Tsujimoto, Shiho; Furusawa, Maiko

    2017-01-01

    High-velocity compact cloud (HVCC) is a peculiar category of molecular clouds detected in the central molecular zone of our Galaxy (Oka et al. 1998, 2007, and 2012). They are characterized by compact appearances (d < 5 pc) and very large velocity widths (Δ V > 50 km s-1). Some of them show high CO J=3-2/J=1-0 intensity ratios (>= 1.5), indicating that they consist of dense and warm molecular gas. Dispite a number of efforts, we have not reached a comprehensive interpretation of HVCCs. Recently, we detected an extraordinaly broad velocity width feature, the `Bullet', in the molecular cloud interacting with the W44 supernova remnant. The Bullet shares essential properties with HVCCs. Because of its proximity, a close inspection of the Bullet must contribute to the understanding of HVCCs.

  11. Gas sensors based on deposited single-walled carbon nanotube networks for DMMP detection

    NASA Astrophysics Data System (ADS)

    Wang, Yanyan; Zhou, Zhihua; Yang, Zhi; Chen, Xiaohang; Xu, Dong; Zhang, Yafei

    2009-08-01

    Sensors based on single-walled carbon nanotube (SWNT) networks were fabricated and their sensitive properties for the nerve agent stimulant dimethyl methylphosphonate (DMMP) vapor were investigated at room temperature. The SWNT networks were deposited on oxidized silicon surface functionalized with 3-aminopropyltrimethysilane (APS). Combining with a traditional silicon process, SWNT-based gas sensors were made at a wafer scale. The effects of the density of deposited SWNTs on the sensor response were studied. The excellent response is obtained under a density of 30-40 tubes µm-2. The sensors exhibit high resistance response, fast response time, rapid recovery and good reproducibility for DMMP vapor. The deposited SWNT sensors will be potentially extended to large-scale fabrication.

  12. Single lung alveolar volume and gas transfer: effect of expansion of the other lung.

    PubMed Central

    Johansen, B.; Bjørtuft, O.

    1994-01-01

    BACKGROUND--Temporary occlusion of one mainstem bronchus permits measurement of single lung function. A previous study suggested that the volume at which one lung is occluded may influence the expansion of the other. The effect of ipsilateral occlusion volume on the contralateral effective alveolar volume (VA, EFF,SL), inspired volume (VI,SL), single breath estimated residual volume (RVSB,SL), carbon monoxide (CO) transfer (TLCO,SL) and transfer coefficient (KCO,SL) has been examined. METHODS--Single breath measurements of CO transfer were made in duplicate in 12 healthy subjects aged 19-44 years, without and during occlusion of one mainstem bronchus by a balloon at RV and at total lung capacity (TLC). RESULTS--Mean VA,EFF,SL, VI,SL, and TLCO,SL were lower during occlusion at RV than during occlusion at TLC (2.84 v 3.26 l; 2.18 v 2.54 l; and 4.70 v 5.51 mmol/kPa/min respectively). RVSB,SL was independent of occlusion volume and KCO,SL not different from the KCO of both lungs (KCO,BL). Single lung values during occlusion at TLC were fairly reproducible and were, except for KCO,SL, approximately half the values for both lungs. During occlusion at RV the second TLCO,SL and KCO,SL were lower than the first. CONCLUSIONS--Occlusion of one lung permits reliable determinations of gas transfer indices of the other, provided the lung is occluded at TLC. Occlusion at RV significantly reduces VA,EFF,SL, and hence TLCO,SL, but does not affect KCO,SL of the other lung. PMID:7878561

  13. Microscopic Shell Model Calculations for sd-Shell Nuclei

    NASA Astrophysics Data System (ADS)

    Barrett, Bruce R.; Dikmen, Erdal; Maris, Pieter; Shirokov, Andrey M.; Smirnova, Nadya A.; Vary, James P.

    Several techniques now exist for performing detailed and accurate calculations of the structure of light nuclei, i.e., A ≤ 16. Going to heavier nuclei requires new techniques or extensions of old ones. One of these is the so-called No Core Shell Model (NCSM) with a Core approach, which involves an Okubo-Lee-Suzuki (OLS) transformation of a converged NCSM result into a single major shell, such as the sd-shell. The obtained effective two-body matrix elements can be separated into core and single-particle (s.p.) energies plus residual two-body interactions, which can be used for performing standard shell-model (SSM) calculations. As an example, an application of this procedure will be given for nuclei at the beginning ofthe sd-shell.

  14. Thermogravimetric characterization and gasification of pecan nut shells.

    PubMed

    Aldana, Hugo; Lozano, Francisco J; Acevedo, Joaquín; Mendoza, Alberto

    2015-12-01

    This study focuses on the evaluation of pecan nut shells as an alternative source of energy through pyrolysis and gasification. The physicochemical characteristics of the selected biomass that can influence the process efficiency, consumption rates, and the product yield, as well as create operational problems, were determined. In addition, the thermal decomposition kinetics necessary for prediction of consumption rates and yields were determined. Finally, the performance of a downdraft gasifier fed with pecan nut shells was analyzed in terms of process efficiency and exit gas characteristics. It was found that the pyrolytic decomposition of the nut shells can be modeled adequately using a single equation considering two independent parallel reactions. The performance of the gasification process can be influenced by the particle size and air flow rate, requiring a proper combination of these parameters for reliable operation and production of a valuable syngas.

  15. Test Plan for the Demonstration of Geophysical Techniques for Single-Shell Tank Leak Detection at the Hanford Mock Tank Site: Fiscal Year 2001

    SciTech Connect

    Barnett, D. Brent; Gee, Glendon W.; Sweeney, Mark D.

    2001-07-31

    As part of the Leak Detection, Monitoring and Mitigation (LDMM) program conducted by CH2M HILL 105-A during FY 2001. These tests are being conducted to assess the applicability of these methods (Electrical Resistance Tomography [ERT], High Resolution Resistivity [HRR], Cross-Borehole Seismography [XBS], Cross-Borehole Radar [XBR], and Cross-Borehole Electromagnetic Induction [CEMI]) to the detection and measurement of Single Shell Tank (SST) leaks into the vadose zone during planned sluicing operations. The testing in FY 2001 will result in the selection of up to two methods for further testing in FY 2002. In parallel with the geophysical tests, a Partitioning Interwell Tracer Test (PITT) study will be conducted simultaneously at the Mock Tank to assess the effectiveness of this technology in detecting and quantifying tank leaks in the vadose zone. Preparatory and background work using Cone Penetrometer methods (CPT) will be conducted at the Mock Tank site and an adjacent test area to derive soil properties for groundtruthing purposes for all methods.

  16. RELATIONSHIP BETWEEN THE SHELL-AVERAGED ENERGY SPECTRUM AND THE FREQUENCY SPECTRUM MEASURED BY A SINGLE SPACECRAFT IN THE SOLAR WIND

    SciTech Connect

    Podesta, J. J.

    2009-05-10

    The relationship between the shell-averaged energy spectrum E(k) and the frequency spectrum P(f) measured by a single spacecraft is needed in studies of solar wind turbulence to allow comparisons between theory and experiment. This relationship is derived for a three-dimensional (scalar) wavevector spectrum of the power-law form that is either isotropic or cylindrically symmetric about the mean magnetic field. In the latter case, it is assumed that the power-law exponents in directions parallel and perpendicular to the mean magnetic field are the same, an assumption that allows the analysis to be performed analytically. The results show that the effects of anisotropy are small when the angle {theta} {sub BV} between the solar wind velocity and the mean magnetic field is between approximately 35 deg. and 90 deg. The largest effects occur near 0 deg. where a significant correction factor is needed compared to the isotropic case due to the lower energy in the k {sub ||} direction compared to the k {sub perpendicular} direction. For solar wind spectra with an unknown degree of anisotropy, measurements of E(k) obtained when 35 deg. {<=} {theta} {sub BV} {<=} 90 deg. should be reasonably accurate for most purposes since even if the spectrum is assumed to be isotropic and no corrections are made for spectral anisotropy, the resulting errors are typically less than 10% or 20%.

  17. Electrochemistry of single nanobubbles. Estimating the critical size of bubble-forming nuclei for gas-evolving electrode reactions.

    PubMed

    German, Sean R; Edwards, Martin A; Chen, Qianjin; Liu, Yuwen; Luo, Long; White, Henry S

    2016-12-12

    In this article, we address the fundamental question: "What is the critical size of a single cluster of gas molecules that grows and becomes a stable (or continuously growing) gas bubble during gas evolving reactions?" Electrochemical reactions that produce dissolved gas molecules are ubiquitous in electrochemical technologies, e.g., water electrolysis, photoelectrochemistry, chlorine production, corrosion, and often lead to the formation of gaseous bubbles. Herein, we demonstrate that electrochemical measurements of the dissolved gas concentration, at the instant prior to nucleation of an individual nanobubble of H2, N2, or O2 at a Pt nanodisk electrode, can be analyzed using classical thermodynamic relationships (Henry's law and the Young-Laplace equation - including non-ideal corrections) to provide an estimate of the size of the gas bubble nucleus that grows into a stable bubble. We further demonstrate that this critical nucleus size is independent of the radius of the Pt nanodisk employed (<100 nm radius), and weakly dependent on the nature of the gas. For example, the measured critical surface concentration of H2 of ∼0.23 M at the instant of bubble formation corresponds to a critical H2 nucleus that has a radius of ∼3.6 nm, an internal pressure of ∼350 atm, and contains ∼1700 H2 molecules. The data are consistent with stochastic fluctuations in the density of dissolved gas, at or near the Pt/solution interface, controlling the rate of bubble nucleation. We discuss the growth of the nucleus as a diffusion-limited process and how that process is affected by proximity to an electrode producing ∼10(11) gas molecules per second. Our study demonstrates the advantages of studying a single-entity, i.e., an individual nanobubble, in understanding and quantifying complex physicochemical phenomena.

  18. Polypyrrole-Functionalized Single-Walled Carbon Nanotube Gas Sensor Arrays

    NASA Astrophysics Data System (ADS)

    Kakoullis, James, Jr.

    The overall objective of this work is to fabricate and evaluate polypyrrole-single-walled carbon nanotubes hybrid structures based chemiresistive sensor arrays for sensitive, selective and discriminative sensing at room temperature of emissions from automobiles and industrial manufacturing. To conceive the sensor arrays single-walled carbon nanotubes (SWNTs) networks were aligned to bridge a 3 mum gap between a pair of prefabricated microelectrodes followed by coating with polypyrrole (PPY) with different dopants by electrochemical polymerization. Initially, the sensor¡¦s synthesis conditions in terms of PPY thickness on SWNTs networks by varying the electropolymerization charge of the monomer pyrrole in presence of LiClO4 dopant for the sensing of NH3 was optimized. Using the optimized polymerization charge of 1 muC determined previously, arrays of SWNTs-PPY hybrid sensors were fabricated by replacing dopant LiClO4 by L-camphor sulfonic acid, D-camphor sulfonic acid, p-toluene sulfonic acid and sodium dodecyl sulfonate. Room temperature gas sensing performance of the PPY coated SWNTs network arrays to gases of environmental significance such as NH3, NO 2, H2S, SO2, CO and CO2 and volatile organic compounds such as benzene, toluene, ethyl benzene, p-xylene, methanol, n-hexane and acetone and humidity, was evaluated. Several folds enhancement in sensing performance was observed towards all the tested analytesfor hybrid devices when compared to bare SWNTs network devices. Differences in sensing performance were noticed for PPY coating with different dopants demonstrating the potential of using the array for discrimination of the tested analytes in a mixture by using chemometric techniques. The underlying sensing mechanism was also investigated by using the devices in chemFET mode configuration.

  19. Single Domain SmCo5@Co Exchange-coupled Magnets Prepared from Core/shell Sm[Co(CN)6]·4H2O@GO Particles: A Novel Chemical Approach

    PubMed Central

    Yang, Ce; Jia, Lihui; Wang, Shouguo; Gao, Chen; Shi, Dawei; Hou, Yanglong; Gao, Song

    2013-01-01

    SmCo5 based magnets with smaller size and larger maximum energy product have been long desired in various fields such as renewable energy technology, electronic industry and aerospace science. However, conventional relatively rough synthetic strategies will lead to either diminished magnetic properties or irregular morphology, which hindered their wide applications. In this article, we present a facile chemical approach to prepare 200 nm single domain SmCo5@Co core/shell magnets with coercivity of 20.7 kOe and saturation magnetization of 82 emu/g. We found that the incorporation of GO sheets is responsible for the generation of the unique structure. The single domain SmCo5 core contributes to the large coercivity of the magnets and the exchange-coupled Co shell enhances the magnetization. This method can be further utilized in the synthesis other Sm-Co based exchange-coupled magnets. PMID:24356309

  20. Single Domain SmCo5@Co Exchange-coupled Magnets Prepared from Core/shell Sm[Co(CN)6].4H2O@GO Particles: A Novel Chemical Approach

    NASA Astrophysics Data System (ADS)

    Yang, Ce; Jia, Lihui; Wang, Shouguo; Gao, Chen; Shi, Dawei; Hou, Yanglong; Gao, Song

    2013-12-01

    SmCo5 based magnets with smaller size and larger maximum energy product have been long desired in various fields such as renewable energy technology, electronic industry and aerospace science. However, conventional relatively rough synthetic strategies will lead to either diminished magnetic properties or irregular morphology, which hindered their wide applications. In this article, we present a facile chemical approach to prepare 200 nm single domain SmCo5@Co core/shell magnets with coercivity of 20.7 kOe and saturation magnetization of 82 emu/g. We found that the incorporation of GO sheets is responsible for the generation of the unique structure. The single domain SmCo5 core contributes to the large coercivity of the magnets and the exchange-coupled Co shell enhances the magnetization. This method can be further utilized in the synthesis other Sm-Co based exchange-coupled magnets.

  1. Single domain SmCo5@Co exchange-coupled magnets prepared from core/shell Sm[Co(CN)6]·4H2O@GO particles: a novel chemical approach.

    PubMed

    Yang, Ce; Jia, Lihui; Wang, Shouguo; Gao, Chen; Shi, Dawei; Hou, Yanglong; Gao, Song

    2013-12-20

    SmCo5 based magnets with smaller size and larger maximum energy product have been long desired in various fields such as renewable energy technology, electronic industry and aerospace science. However, conventional relatively rough synthetic strategies will lead to either diminished magnetic properties or irregular morphology, which hindered their wide applications. In this article, we present a facile chemical approach to prepare 200 nm single domain SmCo5@Co core/shell magnets with coercivity of 20.7 kOe and saturation magnetization of 82 emu/g. We found that the incorporation of GO sheets is responsible for the generation of the unique structure. The single domain SmCo5 core contributes to the large coercivity of the magnets and the exchange-coupled Co shell enhances the magnetization. This method can be further utilized in the synthesis other Sm-Co based exchange-coupled magnets.

  2. Method of preparing gas tags for identification of single and multiple failures of nuclear reactor fuel assemblies

    DOEpatents

    McCormick, Norman J.

    1976-01-01

    For use in the identification of failed fuel assemblies in a nuclear reactor, the ratios of the tag gas isotopic concentrations are located on curved surfaces to enable the ratios corresponding to failure of a single fuel assembly to be distinguished from those formed from any combination of two or more failed assemblies.

  3. Gas-phase Structure and Fragmentation Pathways of Singly Protonated Peptides with N-terminal Arginine

    PubMed Central

    Bythell, Benjamin J.; Csonka, István P.; Suhai, Sándor; Barofsky, Douglas F.; Paizs, Béla

    2010-01-01

    The gas-phase structures and fragmentation pathways of the singly protonated peptide arginylglycylaspartic acid (RGD) are investigated by means of collision-induced-dissociation (CID) and detailed molecular mechanics and density functional theory (DFT) calculations. It is demonstrated that despite the ionizing proton being strongly sequestered at the guanidine group, protonated RGD can easily be fragmented on charge directed fragmentation pathways. This is due to facile mobilization of the C-terminal or aspartic acid COOH protons thereby generating salt-bridge (SB) stabilized structures. These SB intermediates can directly fragment to generate b2 ions or facilely rearrange to form anhydrides from which both b2 and b2+H2O fragments can be formed. The salt-bridge stabilized and anhydride transition structures (TSs) necessary to form b2 and b2+H2O are much lower in energy than their traditional charge solvated counterparts. These mechanisms provide compelling evidence of the role of SB and anhydride structures in protonated peptide fragmentation which complements and supports our recent findings for tryptic systems (Bythell, B. J.; Suhai, S.; Somogyi, A.; Paizs, B. J. Am. Chem. Soc., 2009, 131, 14057–14065.). In addition to these findings we also report on the mechanisms for the formation of the b1 ion, neutral loss (H2O, NH3, guanidine) fragment ions and the d3 ion. PMID:20973555

  4. Consensus statement for inert gas washout measurement using multiple- and single- breath tests.

    PubMed

    Robinson, Paul D; Latzin, Philipp; Verbanck, Sylvia; Hall, Graham L; Horsley, Alexander; Gappa, Monika; Thamrin, Cindy; Arets, Hubertus G M; Aurora, Paul; Fuchs, Susanne I; King, Gregory G; Lum, Sooky; Macleod, Kenneth; Paiva, Manuel; Pillow, Jane J; Ranganathan, Sarath; Ranganathan, Sarah; Ratjen, Felix; Singer, Florian; Sonnappa, Samatha; Stocks, Janet; Subbarao, Padmaja; Thompson, Bruce R; Gustafsson, Per M

    2013-03-01

    Inert gas washout tests, performed using the single- or multiple-breath washout technique, were first described over 60 years ago. As measures of ventilation distribution inhomogeneity, they offer complementary information to standard lung function tests, such as spirometry, as well as improved feasibility across wider age ranges and improved sensitivity in the detection of early lung damage. These benefits have led to a resurgence of interest in these techniques from manufacturers, clinicians and researchers, yet detailed guidelines for washout equipment specifications, test performance and analysis are lacking. This manuscript provides recommendations about these aspects, applicable to both the paediatric and adult testing environment, whilst outlining the important principles that are essential for the reader to understand. These recommendations are evidence based, where possible, but in many places represent expert opinion from a working group with a large collective experience in the techniques discussed. Finally, the important issues that remain unanswered are highlighted. By addressing these important issues and directing future research, the hope is to facilitate the incorporation of these promising tests into routine clinical practice.

  5. Shell forming apparatus

    NASA Technical Reports Server (NTRS)

    Wang, Taylor G. (Inventor); Granett, Dan (Inventor); Akutagawa, Wesley M. (Inventor)

    1987-01-01

    A nozzle assembly is described for use in a system that forms small gas-filled shells, which avoids the need for holding a miniature inner nozzle precisely concentric with a miniature outer nozzle. The outer nozzle has a diameter which is less than about 0.7 millimeter, which results in fluid passing through the nozzle having a progressively greater velocity at locations progressively further from the walls of the outer nozzle across most of the nozzle. This highly variable velocity profile automatically forces gas to the center of the outer nozzle. The end of the inner nozzle, which emits gas, is spaced upstream from the tip of the outer nozzle, to provide a distance along which to center the gas. This self-centering characteristic permits the inner nozzle to be positioned so its axis is not concentric with the axis of the outer nozzle.

  6. A low-temperature process for the denitration of Hanford single-shell tank, nitrate-based waste utilizing the nitrate to ammonia and ceramic (NAC) process

    SciTech Connect

    Mattus, A.J.; Lee, D.D.; Dillow, T.A.; Farr, L.L.; Loghry, S.L.; Pitt, W.W.; Gibson, M.R.

    1994-12-01

    Bench-top feasibility studies with Hanford single-shell tank (SST) simulants, using a new, low-temperature (50 to 60C) process for converting nitrate to ammonia and ceramic (NAC), have conclusively shown that between 85 to 99% of the nitrate can be readily converted. In this process, aluminum powders or shot can be used to convert alkaline, nitrate-based supernate to ammonia and an aluminum oxide-sodium aluminate-based solid which might function as its own waste form. The process may actually be able to utilize already contaminated aluminum scrap metal from various DOE sites to effect the conversion. The final, nearly nitrate-free ceramic-like product can be pressed and sintered like other ceramics. Based upon the starting volumes of 6.2 and 3.1 M sodium nitrate solution, volume reductions of 50 to 55% were obtained for the waste form produced, compared to an expected 35 to 50% volume increase if the Hanford supernate were grouted. Engineering data extracted from bench-top studies indicate that the process will be very economical to operate, and data were used to cost a batch, 1,200-kg NO{sub 3}/h plant for working off Hanford SST waste over 20 years. Their total process cost analysis presented in the appendix, indicates that between $2.01 to 2.66 per kilogram of nitrate converted will be required. Additionally, data on the fate of select radioelements present in solution are presented in this report as well as kinetic, operational, and control data for a number of experiments. Additionally, if the ceramic product functions as its own waste form, it too will offer other cost savings associated with having a smaller volume of waste form as well as eliminating other process steps such as grouting.

  7. Results of Phase I groundwater quality assessment for single-shell tank waste management areas T and TX-TY at the Hanford Site

    SciTech Connect

    Hodges, F.N.

    1998-01-01

    Pacific Northwest National Laboratory (PNNL) conducted a Phase I, Resource Conservation and Recovery Act of 1976 (RCRA) groundwater quality assessment for the Richland Field Office of the U.S. Department of Energy (DOE-RL) under the requirements of the Federal Facility Compliance Agreement. The purpose of the investigation was to determine if the Single-Shell Tank Waste Management Areas (WMAs) T and TX-TY have impacted groundwater quality. Waste Management Areas T and TX-TY, located in the northern part of the 200 West Area of the Hanford Site, contain the 241-T, 241-TX, and 241-TY tank farms and ancillary waste systems. These two units are regulated under RCRA interim-status regulations (under 40 CFR 265.93) and were placed in assessment groundwater monitoring because of elevated specific conductance in downgradient wells. Anomalous concentrations of technetium-99, chromium, nitrate, iodine-129, and cobalt-60 also were observed in some downgradient wells. Phase I assessment, allowed under 40 CFR 265, provides the owner-operator of a facility with the opportunity to show that the observed contamination has a source other than the regulated unit. For this Phase I assessment, PNNL evaluated available information on groundwater chemistry and past waste management practices in the vicinity of WMAs T and TX-TY. Background contaminant concentrations in the vicinity of WMAs T and TX-TY are the result of several overlapping contaminant plumes resulting from past-practice waste disposal operations. This background has been used as baseline for determining potential WMA impacts on groundwater.

  8. Addendum to the RCRA Assessment Report for Single-Shell Tank Waste Management Area S-SX at the Hanford Site

    SciTech Connect

    Chou, C.J.; Johnson, V.G.

    1999-10-07

    The initial Resource Conservation and Recovery Act (RCRA) groundwater quality assessment report for Waste Management Area S-SX (PNNL-11810) was issued in January 1998. The report stated a plan for conducting continued assessment would be developed after addressing Washington State Department of Ecology (Ecology) comments on initial findings in PNNL-11810. Comments from Ecology were received by US Department of Energy, Richland Operations Office (DOE-RL) on September 24, 1998. Shortly thereafter, Ecology and DOE began dispute resolution and related negotiations about tank farm vadose issues. This led to proposed new Tri-Party Agreement milestones covering a RCRA Facility Investigation-Corrective Measures Study (RFI/CMS) of the four single-shell tank farm waste management areas that were in assessment status (Waste Management Areas B-BX-BY, S-SX, T and TX-TY). The RCRA Facility Investigation includes both subsurface (vadose zone and groundwater) and surface (waste handling facilities and grounds) characterization. Many of the Ecology comments on PNNL-11810 are more appropriate for, and in many cases are superseded by, the RFI/CMS at Waste Management Area S-SX. The proposed Tri-Party Agreement milestone changes that specify the scope and schedule for the RFI/CMS work plans (Tri-Party Agreement change number M-45-98-0) were issued for public comment in February 1999. The Tri-Party Agreement narrative indicates the ongoing groundwater assessments will be integrated with the RFI/CMS work plans. This addendum documents the disposition of the Ecology comments on PNNL-11810 and identifies which comments were more appropriate for the RFI/CMS work plan.

  9. Parametric Trends in the Combustion Stability Characteristics of a Single-Element Gas-Gas Rocket Engine

    DTIC Science & Technology

    2013-12-01

    High Performance Computing Modernization Program. References 1Oefelein, J . and Yang, V., “Comprehensive Review of Liquid-Propellant Combustion...of Combustion Instability in Motors: Case Studies,” 37th AIAA/ASME/ SAE /ASEE Joint Propulsion Conference and Exhibit , Salt Lake City, Utah, July 2001...gas coaxial rocket injector,” 49th AIAA/ASME/ SAE /ASEE Joint Propulsion Conference and Exhibit , AIAA, San Jose, CA, July 2013. 4Garby, R., Selle, L

  10. Gas chromatographic determination and mechanism of formation of D-amino acids occurring in fermented and roasted cocoa beans, cocoa powder, chocolate and cocoa shell.

    PubMed

    Pätzold, R; Brückner, H

    2006-07-01

    Fermented cocoa beans of various countries of origin (Ivory Coast, Ghana, Sulawesi), cocoa beans roasted under defined conditions (100-150 degrees C; 30-120 min), low and high fat cocoa powder, various brands of chocolate, and cocoa shells were analyzed for their contents of free L-and D-amino acids. Amino acids were isolated from defatted products using a cation exchanger and converted into volatile N(O)-pentafluoropropionyl amino acid 2-propyl esters which were analyzed by enantioselective gas chromatography mass spectrometry on a Chirasil-L-Val capillary column. Besides common protein L-amino acids low amounts of D-amino acids were detected in fermented cocoa beans. Quantities of D-amino acids increased on heating. On roasting cocoa beans of the Forastero type from the Ivory Coast at 150 degrees C for 2 h, relative quantities of D-amino acids approached 17.0% D-Ala, 11.7% D-Ile, 11.1% D-Asx (Asp + Asn), 7.9% D-Tyr, 5.8% D-Ser, 4.8% D-Leu, 4.3% D-Phe, 37.0% D-Pro, and 1.2% D-Val. In cocoa powder and chocolate relative quantities amounted to 14.5% D-Ala, 10.6% D-Tyr, 9.8% D-Phe, 8.1% L-Asx, and 7.2% D-Ile. Lower quantities of other D-amino acids were also detected. In order to corroborate our hypothesis that D-amino acids are generated from Amadori compounds (fructose amino acids) formed in the course of the Maillard reaction, fructose-L-phenylalanine and fructose-D-phenylalanine were synthesized and heated at 200 degrees C for 5-60 min. Already after 5 min release of 11.7% D-Phe and 11.8% L-Phe in the free form could be analyzed. Based on the data a racemization mechanism is presented founded on the intermediate and reversible formation of an amino acid carbanion in the Amadori compounds.

  11. The relation between photoluminescence properties and gas pressure with [0001] InGaN single quantum well systems

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Toshiaki; Alfieri, Giovanni; Kawakami, Yoichi; Micheletto, Ruggero

    2017-01-01

    We show for the first time that photoluminescence of InGaN single quantum wells (SQW) devices is related to the gas pressure in which the sample is immersed, also we give a model of the phenomena to suggest a possible cause. Our model shows a direct relation between experimental behavior and molecular coverage dynamics. This strongly suggests that the driving force of photoluminescence decrease is oxygen covering the surface of the device with a time dynamics that depends on the gas pressure. This aims to contribute to the understanding of the physical mechanism of the so-called optical memory effect and blinking phenomenon observed in these devices.

  12. The sensitivity of gas sensor based on single ZnO nanowire modulated by helium ion radiation

    SciTech Connect

    Liao, L.; Lu, H. B.; Li, J. C.; Liu, C.; Fu, D. J.; Liu, Y. L.

    2007-10-22

    In this letter, we present a gas sensor using a single ZnO nanowire as a sensing unit. This ZnO nanowire-based sensor has quick and high sensitive response to H{sub 2}S in air at room temperature. It has also been found that the gas sensitivity of the ZnO nanowires could be modulated and enhanced by He{sup +} implantation at an appropriate dose. A possible explanation is given based on the modulation model of the depletion layer.

  13. Carbon nanotubes based transistors composed of single-walled carbon nanotubes mats as gas sensors: A review

    NASA Astrophysics Data System (ADS)

    Bondavalli, Paolo

    2010-06-01

    This contribution presents the main studies on the CNTFET based gas sensors obtained using Single-Walled Carbon Nanotubes mats (SWCNTs) as channel. Although these devices have allowed one to achieve sensors with an impressive sensitivity compared to existing technologies, the physical interpretation of the effect of interaction between the gas molecules and the CNTFETs has not yet been clarified. Concerning selectivity, we will deal with the main routes that have been proposed to overcome this problem: functionalization using polymers, electrodes metal diversification, metal decoration of SWCNT mats.

  14. Shell Games.

    ERIC Educational Resources Information Center

    Atkinson, Bill

    1982-01-01

    The author critiques the program design and educational aspects of the Shell Games, a program developed by Apple Computer, Inc., which can be used by the teacher to design objective tests for adaptation to specific assessment needs. (For related articles, see EC 142 959-962.) (Author)

  15. Single-step syngas-to-dimethyl ether processes for optimal productivity, minimal emissions, and natural gas-derived syngas

    SciTech Connect

    Peng, X.D.; Wang, A.W.; Toseland, B.A.; Tijm, P.J.A.

    1999-11-01

    Process schemes for single-step syngas-to-dimethyl ether (DME) were developed in two stages: (1) the performance of the syngas-to-DME reactor was optimized with respect to the feed gas composition and (2) the optimal reactor feed gas system was integrated with synthesis gas generators. It was shown that the reactor performance is very sensitive to the H{sub 2}:CO ratio in the feed gas. The optimal DME productivity and best material utilization were obtained with a feed gas containing 50% hydrogen and 50% carbon monoxide. In the second phase the syngas generation units considered were CO{sub 2}-methane reformer, steam-methane reformer, methane partial oxidation, and coal gasifier. The integration adjusts the H{sub 2}:CO ratio in natural gas-derived syngas to fit the optimal DME reactor operation and minimizes CO{sub 2} emissions and material loss. The technical feasibility of these schemes was demonstrated by simulations using realistic reactor models, kinetics, and thermodynamics under commercially relevant conditions.

  16. Effects of Fuel Spray Modeling on Combustion Instability Predictions in a Single-Element Lean Direct Injection (LDI) Gas Turbine Combustor

    DTIC Science & Technology

    2014-09-01

    Modeling on Combustion Instability Predictions in a Single- Element Lean Direct Injection (LDI) Gas Turbine Combustor 5b. GRANT NUMBER 5c. PROGRAM...injection (LDI) gas turbine combustor were performed to assess the effects of fuel spray modeling in predicting combustion instability. Concurrently...239.18 Effects of Fuel Spray Modeling on Combustion Instability Predictions in a Single-Element Lean Direct Injection (LDI) Gas Turbine

  17. Vibration of Shells

    NASA Technical Reports Server (NTRS)

    Leissa, A. W.

    1973-01-01

    The vibrational characteristics and mechanical properties of shell structures are discussed. The subjects presented are: (1) fundamental equations of thin shell theory, (2) characteristics of thin circular cylindrical shells, (3) complicating effects in circular cylindrical shells, (4) noncircular cylindrical shell properties, (5) characteristics of spherical shells, and (6) solution of three-dimensional equations of motion for cylinders.

  18. An Initial Evaluation of Characterization and Closure Options for Underground Pipelines within a Hanford Site Single-Shell Tank Farm - 13210

    SciTech Connect

    Badden, Janet W.; Connelly, Michael P.; Seeley, Paul N.; Hendrickson, Michelle L.

    2013-07-01

    The Hanford Site includes 149 single-shell tanks, organized in 12 'tank farms,' with contents managed as high-level mixed waste. The Hanford Federal Facility Agreement and Consent Order requires that one tank farm, the Waste Management Area C, be closed by June 30, 2019. A challenge to this project is the disposition and closure of Waste Management Area C underground pipelines. Waste Management Area C contains nearly seven miles of pipelines and 200 separate pipe segments. The pipelines were taken out of service decades ago and contain unknown volumes and concentrations of tank waste residuals from past operations. To understand the scope of activities that may be required for these pipelines, an evaluation was performed. The purpose of the evaluation was to identify what, if any, characterization methods and/or closure actions may be implemented at Waste Management Area C for closure of Waste Management Area C by 2019. Physical and analytical data do not exist for Waste Management Area C pipeline waste residuals. To develop estimates of residual volumes and inventories of contamination, an extensive search of available information on pipelines was conducted. The search included evaluating historical operation and occurrence records, physical attributes, schematics and drawings, and contaminant inventories associated with the process history of plutonium separations facilities and waste separations and stabilization operations. Scoping analyses of impacts to human health and the environment using three separate methodologies were then developed based on the waste residual estimates. All analyses resulted in preliminary assessments, indicating that pipeline waste residuals presented a comparably low long-term impact to groundwater with respect to soil, tank and other ancillary equipment residuals, but exceeded Washington State cleanup requirement values. In addition to performing the impact analyses, the assessment evaluated available sampling technologies and

  19. Ultrasensitive and Highly Selective Graphene-Based Single Yarn for Use in Wearable Gas Sensor

    PubMed Central

    Ju Yun, Yong; Hong, Won G.; Choi, Nak-Jin; Hoon Kim, Byung; Jun, Yongseok; Lee, Hyung-Kun

    2015-01-01

    Electric components based on fibers or textiles have been investigated owing to their potential applications in wearable devices. High performance on response to gas, drape-ability and washing durability are of important for gas sensors based on fiber substrates. In this report, we demonstrate the bendable and washable electronic textile (e-textile) gas sensors composed of reduced graphene oxides (RGOs) using commercially available yarn and molecular glue through an electrostatic self-assembly. The e-textile gas sensor possesses chemical durability to several detergent washing treatments and mechanical stability under 1,000 bending tests at an extreme bending radius of 1 mm as well as a high response to NO2 gas at room temperature with selectivity to other gases such as acetone, ethanol, ethylene, and CO2. PMID:26043109

  20. Ultrasensitive and Highly Selective Graphene-Based Single Yarn for Use in Wearable Gas Sensor

    NASA Astrophysics Data System (ADS)

    Ju Yun, Yong; Hong, Won G.; Choi, Nak-Jin; Hoon Kim, Byung; Jun, Yongseok; Lee, Hyung-Kun

    2015-06-01

    Electric components based on fibers or textiles have been investigated owing to their potential applications in wearable devices. High performance on response to gas, drape-ability and washing durability are of important for gas sensors based on fiber substrates. In this report, we demonstrate the bendable and washable electronic textile (e-textile) gas sensors composed of reduced graphene oxides (RGOs) using commercially available yarn and molecular glue through an electrostatic self-assembly. The e-textile gas sensor possesses chemical durability to several detergent washing treatments and mechanical stability under 1,000 bending tests at an extreme bending radius of 1 mm as well as a high response to NO2 gas at room temperature with selectivity to other gases such as acetone, ethanol, ethylene, and CO2.

  1. Ultrasensitive and highly selective graphene-based single yarn for use in wearable gas sensor.

    PubMed

    Yun, Yong Ju; Hong, Won G; Choi, Nak-Jin; Kim, Byung Hoon; Jun, Yongseok; Lee, Hyung-Kun

    2015-06-04

    Electric components based on fibers or textiles have been investigated owing to their potential applications in wearable devices. High performance on response to gas, drape-ability and washing durability are of important for gas sensors based on fiber substrates. In this report, we demonstrate the bendable and washable electronic textile (e-textile) gas sensors composed of reduced graphene oxides (RGOs) using commercially available yarn and molecular glue through an electrostatic self-assembly. The e-textile gas sensor possesses chemical durability to several detergent washing treatments and mechanical stability under 1,000 bending tests at an extreme bending radius of 1 mm as well as a high response to NO2 gas at room temperature with selectivity to other gases such as acetone, ethanol, ethylene, and CO2.

  2. An investigation into the flow behavior of a single phase gas system and a two phase gas/liquid system in normal gravity with nonuniform heating from above

    NASA Technical Reports Server (NTRS)

    Disimile, Peter J.; Heist, Timothy J.

    1990-01-01

    The fluid behavior in normal gravity of a single phase gas system and a two phase gas/liquid system in an enclosed circular cylinder heated suddenly and nonuniformly from above was investigated. Flow visualization was used to obtain qualitative data on both systems. The use of thermochromatic liquid crystal particles as liquid phase flow tracers was evaluated as a possible means of simultaneously gathering both flow pattern and temperature gradient data for the two phase system. The results of the flow visualization experiments performed on both systems can be used to gain a better understanding of the behavior of such systems in a reduced gravity environment and aid in the verification of a numerical model of the system.

  3. Creation and recovery of a W(111) single atom gas field ion source.

    PubMed

    Pitters, Jason L; Urban, Radovan; Wolkow, Robert A

    2012-04-21

    Tungsten single atom tips have been prepared from a single crystal W(111) oriented wire using the chemical assisted field evaporation and etching method. Etching to a single atom tip occurs through a symmetric structure and leads to a predictable last atom unlike etching with polycrystalline tips. The single atom tip formation procedure is shown in an atom by atom removal process. Rebuilds of single atom tips occur on the same crystalline axis as the original tip such that ion emission emanates along a fixed direction for all tip rebuilds. This preparation method could be utilized and developed to prepare single atom tips for ion source development.

  4. 10 cm x 10 cm Single Gas Electron Multiplier (GEM) X-ray Fluorescence Detector for Dilute Elements

    NASA Astrophysics Data System (ADS)

    Shaban, E. H.; Siddons, D. P.; Seifu, D.

    2014-03-01

    We have built and tested a 10 cm × 10 cm single Gas Electron Multiplier (GEM) X-ray detector to probe dilute amounts of Fe in a prepared sample. The detector uses Argon/Carbon Dioxide (75/25) gas mixture flowing at a slow rate through a leak proof Plexi-glass enclosure held together by O-rings and screws. The Fluorescence X-ray emitted by the element under test is directed through a Mylar window into the drift region of the detector where abundant gas is flowing. The ionized electrons are separated, drifted into the high electric field of the GEM, and multiplied by impact ionization. The amplified negatively charged electrons are collected and further amplified by a Keithley amplifier to probe the absorption edge of the element under test using X-ray absorption spectroscopy technique. The results show that the GEM detector provided good results with less noise as compared with a Silicon drift detector (SDD).

  5. Structure and mechanism of the formation of core–shell nanoparticles obtained through a one-step gas-phase synthesis by electron beam evaporation

    PubMed Central

    Bardakhanov, Sergey P; Schreiber, Makoto; Bazarova, Dashima G; Romanov, Nikolai A; Baldanov, Boris B; Radnaev, Bair R; Syzrantsev, Viacheslav V

    2015-01-01

    Summary The structure of core–shell Cu@silica and Ag@Si nanoparticles obtained in one-step through evaporation of elemental precursors by a high-powered electron beam are investigated. The structure of the core and shell of the particles are investigated in order to elucidate their mechanisms of formation and factors affecting the synthesis. It is proposed that the formation of Cu@silica particles is mainly driven by surface tension differences between Cu and Si while the formation of Ag@Si particles is mainly driven by differences in the vapour concentration of the two components. PMID:25977857

  6. Structure and mechanism of the formation of core-shell nanoparticles obtained through a one-step gas-phase synthesis by electron beam evaporation.

    PubMed

    Nomoev, Andrey V; Bardakhanov, Sergey P; Schreiber, Makoto; Bazarova, Dashima G; Romanov, Nikolai A; Baldanov, Boris B; Radnaev, Bair R; Syzrantsev, Viacheslav V

    2015-01-01

    The structure of core-shell Cu@silica and Ag@Si nanoparticles obtained in one-step through evaporation of elemental precursors by a high-powered electron beam are investigated. The structure of the core and shell of the particles are investigated in order to elucidate their mechanisms of formation and factors affecting the synthesis. It is proposed that the formation of Cu@silica particles is mainly driven by surface tension differences between Cu and Si while the formation of Ag@Si particles is mainly driven by differences in the vapour concentration of the two components.

  7. Building Atoms Shell by Shell.

    ERIC Educational Resources Information Center

    Sussman, Beverly

    1993-01-01

    Describes an atom-building activity where students construct three-dimensional models of atoms using a styrofoam ball as the nucleus and pom-poms, gum drops, minimarshmallows, or other small items of two different colors to represent protons and neutrons attached. Rings of various sizes with pom-poms attached represent electron shells and…

  8. Ni(NiO)/single-walled carbon nanotubes composite: Synthesis of electro-deposition, gas sensing property for NO gas and density functional theory calculation

    SciTech Connect

    Li, Li; Zhang, Guo; Chen, Lei; Bi, Hong-Mei; Shi, Ke-Ying

    2013-02-15

    Graphical abstract: The Ni(NiO)/semiconducting single-walled carbon nanotubes composite collected from the cathode after electro-deposition shows a high sensitivity to low-concentration NO gas at room temperature (18 °C). Display Omitted Highlights: ► Ni(NiO) nanoparticles were deposited on semiconducting SWCNTs by electro-deposition. ► Ni(NiO)/semiconducting SWCNTs film shows a high sensitivity to NO gas at 18 °C. ►Theoretical calculation reveals electron transfer from SWCNTs to NO via Ni. -- Abstract: Single-walled carbon nanotubes which contains metallic SWCNTs (m-SWCNTs) and semiconducting SWCNTs (s-SWCNTs) have been obtained under electric arc discharge. Their separation can be effectively achieved by the electro-deposition method. The Ni(NiO)/s-SWCNTs composite was found on cathode where Ni was partially oxidized to NiO at ambient condition with Ni(NiO) nanoparticles deposited uniformly on the bundles of SWCNTs. These results were confirmed by Raman spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–vis–NIR and TG characterizations. Furthermore, investigation of the gas sensing property of Ni(NiO)/s-SWCNTs composite film to NO gas at 18 °C demonstrated the sensitivity was approximately 5% at the concentration of 97 ppb. Moreover, density functional theory (DFT) calculations were performed to explore the sensing mechanism which suggested the adsorption of NO molecules onto the composite through N–Ni interaction as well as the proposition of electron transfer mechanisms from SWCNTs to NO via the Ni medium.

  9. Application of ZnO single-crystal wire grown by the thermal evaporation method as a chemical gas sensor for hydrogen sulfide.

    PubMed

    Park, N K; Lee, S Y; Lee, T J

    2011-01-01

    A zinc oxide single-crystal wire was synthesized for application as a gas-sensing material for hydrogen sulfide, and its gas-sensing properties were investigated in this study. The gas sensor consisted of a ZnO thin film as the buffer layer and a ZnO single-crystal wire. The ZnO thin film was deposited over a patterning silicon substrate with a gold electrode by the CFR method. The ZnO single-crystal wire was synthesized over the ZnO thin film using zinc and activated carbon as the precursor for the thermal evaporation method at 800 degrees C. The electrical properties of the gas sensors that were prepared for the growth of ZnO single-crystal wire varied with the amount of zinc contained in the precursor. The charged current on the gas sensors increased with the increasing amount of zinc in the precursor. It was concluded that the charged current on the gas sensors was related to ZnO single-crystal wire growth on the silicon substrate area between the two electrodes. The charged current on the gas sensor was enhanced when the ZnO single-crystal wire was exposed to a H2S stream. The experimental results obtained in this study confirmed that a ZnO single-crystal wire can be used as a gas sensor for H2S.

  10. Large ultrathin shelled drops produced via non-confined microfluidics.

    PubMed

    Chaurasia, Ankur S; Josephides, Dimitris N; Sajjadi, Shahriar

    2015-02-02

    We present a facile approach for producing large and monodisperse core-shell drops with ultrathin shells using a single-step process. A biphasic compound jet is introduced into a quiescent third (outer) phase that ruptures to form core-shell drops. Ultrathin shelled drops could only be produced within a certain range of surfactant concentrations and flow rates, highlighting the effect of interfacial tension in engulfing the core in a thin shell. An increase in surfactant concentrations initially resulted in drops with thinner shells. However, the drops with thinnest shells were obtained at an optimum surfactant concentration, and a further increase in the surfactant concentrations increased the shell thickness. Highly monodisperse (coefficient of variation smaller than 3 %) core-shell drops with diameter of ∼200 μm-2 mm with shell thickness as small as ∼2 μm were produced. The resulting drops were stable enough to undergo polymerisation and produce ultrathin shelled capsules.

  11. The Study of Single-Pass GMA Welds with Different Cover Gas Compositions on HSLA-100 Steel

    DTIC Science & Technology

    1993-09-23

    steels contributes to better weldability, lowers the susceptibility to hydrogen cracking and lower ductile to brittle transition temperature ( DBTT ...COMPOSITIONS ON HSLA-100 STEEL by Ricky Arthur Seraiva September, 1993 Thesis Advisor: Alan G. Fox Approved for public release; distribution is unlimited...TITLE AND SUBTITLE THE STUDY OF SINGLE-PASS GMA 5. FUNDING NUMBERS WELDS WITH DIFFERENT COVER GAS COMPOSITIONS ON HSLA-1O0 STEEL 6. AUTHOR(S) Ricky

  12. Structural changes and damage of single-crystal turbine blades during life tests of an aviation gas turbine engine

    NASA Astrophysics Data System (ADS)

    Ospennikova, O. G.; Orlov, M. R.; Kolodochkina, V. G.; Nazarkin, R. M.

    2015-04-01

    The irreversible structural changes of the single-crystal ZhS32-VI nickel superalloy blades of a high-pressure turbine that occur during life tests of a gas turbine engine are studied. The main operation damages in the hottest section of the blade airfoil are found to be the fracture of the heat-resistant coating in the leading edge and the formation of thermomechanical fatigue cracks. The possibility of reconditioning repair of the blades is considered.

  13. Development and Design of a Single-Stage Cryogenic Modulator for Comprehensive Two-Dimensional Gas Chromatography.

    PubMed

    Mostafa, Ahmed; Górecki, Tadeusz

    2016-05-17

    A new liquid nitrogen-based single-stage cryogenic modulator was developed and characterized. In addition, a dedicated liquid nitrogen delivery system was developed. A well-defined restriction placed inside a deactivated fused silica capillary was used to increase the cooling surface area and provide very efficient trapping. At the same time, it enabled modulation of the carrier gas flow owing to changes in gas viscosity with temperature. Gas flow is almost unimpeded at the trapping temperature but reduced to nearly zero at the desorption temperature, which prevents analyte breakthrough. Peak widths for n-alkanes of 30-40 ms at half height were obtained. Most importantly, even the solvent peak could be modulated, which is not feasible with any commercially available thermal modulator. Evaluation of the newly developed system in two-dimensional gas chromatography (GC × GC) separations of some real samples such as regular gasoline and diesel fuel showed that the analytical performance of this single-stage modulator is fully competitive to those of the more complicated dual-stage modulators.

  14. Shell worlds

    NASA Astrophysics Data System (ADS)

    Roy, Kenneth I.; Kennedy, Robert G., III; Fields, David E.

    2013-02-01

    The traditional concept of terraforming assumes ready availability of candidate planets with acceptable qualities: orbiting a star in its "Goldilocks zone", liquid water, enough mass, years longer than days, magnetic field, etc. But even stipulating affordable interstellar travel, we still might never find a good candidate elsewhere. Whatever we found likely would require centuries of heavy terraforming, just as Mars or Venus would here. Our increasing appreciation of the ubiquity of life suggests that any terra nova would already possess it. We would then face the dilemma of introducing alien life forms (us, our microbes) into another living world. Instead, we propose a novel method to create habitable environments for humanity by enclosing airless, sterile, otherwise useless planets, moons, and even large asteroids within engineered shells, which avoids the conundrum. These shells are subject to two opposing internal stresses: compression due to the primary's gravity, and tension from atmospheric pressure contained inside. By careful design, these two cancel each other resulting in zero net shell stress. Beneath the shell an Earth-like environment could be created similar in almost all respects to that of Home, except for gravity, regardless of the distance to the sun or other star. Englobing a small planet, moon, or even a dwarf planet like Ceres, would require astronomical amounts of material (quadrillions of tons) and energy, plus a great deal of time. It would be a quantum leap in difficulty over building Dyson Dots or industrializing our solar system, perhaps comparable to a mission across interstellar space with a living crew within their lifetime. But when accomplished, these constructs would be complete (albeit small) worlds, not merely large habitats. They could be stable across historic timescales, possibly geologic. Each would contain a full, self-sustaining ecology, which might evolve in curious directions over time. This has interesting implications

  15. Shell's Middle Distillate Synthesis process

    SciTech Connect

    Voetter, H.; VanDerBurgt, M.J. B.V., The Hague )

    1988-01-01

    The basis of the Shell Middle Distillate Synthesis (SMDS) process is the classic Fischer-Tropsch synthesis. For the case of middle distillate production from natural gas the procedure has been developed to commercial maturity, making use of tailored line-up for synthesis gas production and of proprietary modern catalysts in synthesis. Development work over the last years has in particular lead to improvement of the economy of the process altogether via catalyst performance, reactor sizing and syngas manufacturing line-up.

  16. Stress analysis and fatigue evaluation of shell-to-footer plate joint in liquefied natural gas (LNG) storage tanks. Final topical report

    SciTech Connect

    Lewis, J.P.; Outtrim, P.A.; Tong, R.T.

    1996-09-01

    The life extension efforts were initiated to gather, evaluate, and provide LNG facility operators and storage tank designers with information that will help support assurances for long-term structural integrity. For this specific effort, the evaluation of a critical tank element, i.e. the shell-to-footer plate weld was conducted.

  17. Galactic evolution. I - Single-zone models. [encompassing stellar evolution and gas-star dynamic theories

    NASA Technical Reports Server (NTRS)

    Thuan, T. X.; Hart, M. H.; Ostriker, J. P.

    1975-01-01

    The two basic approaches of physical theory required to calculate the evolution of a galactic system are considered, taking into account stellar evolution theory and the dynamics of a gas-star system. Attention is given to intrinsic (stellar) physics, extrinsic (dynamical) physics, and computations concerning the fractionation of an initial mass of gas into stars. The characteristics of a 'standard' model and its variants are discussed along with the results obtained with the aid of these models.

  18. Gas pollutants removal in a single- and two-stage ejector-venturi scrubber.

    PubMed

    Gamisans, Xavier; Sarrà, Montserrrat; Lafuente, F Javier

    2002-03-29

    The absorption of SO(2) and NH(3) from the flue gas into NaOH and H(2)SO(4) solutions, respectively has been studied using an industrial scale ejector-venturi scrubber. A statistical methodology is presented to characterise the performance of the scrubber by varying several factors such as gas pollutant concentration, air flowrate and absorbing solution flowrate. Some types of venturi tube constructions were assessed, including the use of a two-stage venturi tube. The results showed a strong influence of the liquid scrubbing flowrate on pollutant removal efficiency. The initial pollutant concentration and the gas flowrate had a slight influence. The use of a two-stage venturi tube considerably improved the absorption efficiency, although it increased energy consumption. The results of this study will be applicable to the optimal design of venturi-based absorbers for gaseous pollution control or chemical reactors.

  19. No loss single line fueling station for liquid natural gas vehicles

    SciTech Connect

    Cieslukowski, R.E.

    1993-08-03

    A no loss fueling station is described for delivery of liquid natural gas (LNG) to a fuel tank of a use device such as a motor vehicle, comprising: (a) a pressure building tank holding a quantity of LNG and a natural gas head; (b) first means for selectively building the pressure and temperature in the pressure building tank; (c) second means for selectively reducing the pressure and temperature in the pressure building tank; (d) means for controlling the first and second means to maintain a desired pressure and temperature in the pressure building tank without venting natural gas to the atmosphere; and (e) means for delivering LNG from the pressure building tank to the use device.

  20. Radiation of X-rays using polarized LiNbO3 single crystal in low-pressure ambient gas.

    PubMed

    Fukao, Shinji; Nakanishi, Yoshikazu; Mizoguchi, Tadahiro; Ito, Yoshiaki; Yoshikado, Shinzo

    2009-09-01

    The dependence of X-ray intensity on the pressure and type of ambient gas was investigated for LiNbO(3) single crystals polarized in the c-axis direction at pressures of approximately 1 to 30 Pa. Ionization of surrounding gas molecules by the electric field generated by the crystal led to the production of both positive ions and free electrons. The electrons were accelerated toward a Cu target, radiating both white X-rays and X-rays specific to the crystal or target material by bremsstrahlung. The integrated X-ray intensity per cycle in the energy range 1 to 20 keV showed a local maximum value at a pressure P(max). The logarithm of P(max) was proportional to the Boltzmann factor using the first ionization energy of each ambient gas molecule. The value of P(max) was found to be independent of the electrical surface area of the crystal. The integrated X-ray intensity was approximated qualitatively by a quadratic function with pressure, which was upwardly convex. It was found that one of the causes of the reduction in X-ray intensity at pressures P > P(max) is the adsorption of positive ions generated by the ionization of gas molecules on the negative electric surface. It was also discovered that the lifetime of the X-ray radiation device could be improved when the X-ray radiation case was covered with another hermetically sealed decompression case. The gas with the smallest first ionization energy, with a partial pressure of P(max), was enclosed inside the X-ray radiation case (inner case) and the gas with the largest first ionization energy was enclosed at a suitable pressure between the inner and outer cases.

  1. Advances in shell side condensation for refrigerants

    NASA Astrophysics Data System (ADS)

    Webb, Ralph L.

    The design of shell and tube condensers used in air conditioning and refrigeration applications is discussed. The geometry of interest involves condensation on the shell side of a horizontal tube bundle. Enhanced heat transfer geometries are typically used for condensation on the shell side. The heat transfer is removed by water on the tube side, which typically have tube side enhancement. Single tube and row effect condensation data are presented. Thermal design methods for sizing of the condenser are outlined.

  2. Determination of chlorine concentration using single temperature modulated semiconductor gas sensor

    NASA Astrophysics Data System (ADS)

    Woźniak, Ł.; Kalinowski, P.; Jasiński, G.; Jasiński, P.

    2016-11-01

    A periodic temperature modulation using sinusoidal heater voltage was applied to a commercial SnO2 semiconductor gas sensor. Resulting resistance response of the sensor was analyzed using a feature extraction method based on Fast Fourier Transformation (FFT). The amplitudes of the higher harmonics of the FFT from the dynamic nonlinear responses of measured gas were further utilized as an input for Artificial Neuron Network (ANN). Determination of the concentration of chlorine was performed. Moreover, this work evaluates the sensor performance upon sinusoidal temperature modulation.

  3. Differences and Commonalities in the Gas-Phase Reactions of Closed-Shell Metal Dioxide Clusters [MO2 ](+) (M=V, Nb, and Ta) with Methane.

    PubMed

    Zhou, Shaodong; Li, Jilai; Schlangen, Maria; Schwarz, Helmut

    2016-05-17

    High-level electronic structure calculations, in combination with Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometric studies, permit the mechanism by which closed-shell, "naked" [TaO2 ](+) brings about C-H bond activation of methane to be revealed. These studies also help to understand why the lighter congeners of [MO2 ](+) (M=V, Nb) are unreactive under ambient conditions.

  4. Photothermal desorption of single-walled carbon nanotubes and coconut shell-activated carbons using a continuous light source for application in air sampling.

    PubMed

    Floyd, Evan L; Sapag, Karim; Oh, Jonghwa; Lungu, Claudiu T

    2014-08-01

    Many techniques exist to measure airborne volatile organic compounds (VOCs), each with differing advantages; sorbent sampling is compact, versatile, has good sample stability, and is the preferred technique for collecting VOCs for hygienists. Development of a desorption technique that allows multiple analyses per sample (similar to chemical desorption) with enhanced sensitivity (similar to thermal desorption) would be helpful to field hygienists. In this study, activated carbon (AC) and single-walled carbon nanotubes (SWNT) were preloaded with toluene vapor and partially desorbed with light using a common 12-V DC, 50-W incandescent/halogen lamp. A series of experimental chamber configurations were explored starting with a 500-ml chamber under static conditions, then with low ventilation and high ventilation, finally a 75-ml high ventilation chamber was evaluated. When preloaded with toluene and irradiated at the highest lamp setting for 4min, AC desorbed 13.9, 18.5, 23.8, and 45.9% of the loaded VOC mass, in each chamber configuration, respectively; SWNT desorbed 25.2, 24.3, 37.4, and 70.5% of the loaded VOC mass, respectively. SWNT desorption was significantly greater than AC in all test conditions (P = 0.02-<0.0001) demonstrating a substantial difference in sorbent performance. When loaded with 0.435mg toluene and desorbed at the highest lamp setting for 4min in the final chamber design, the mean desorption for AC was 45.8% (39.7, 52.0) and SWNT was 72.6% (68.8, 76.4) (mean represented in terms of 95% confidence interval). All desorption measurements were obtained using a field grade photoionization detector; this demonstrates the potential of using this technique to perform infield prescreening of VOC samples for immediate exposure feedback and in the analytical lab to introduce sample to a gas chromatograph for detailed analysis of the sample.

  5. Photothermal Desorption of Single-Walled Carbon Nanotubes and Coconut Shell-Activated Carbons Using a Continuous Light Source for Application in Air Sampling

    PubMed Central

    Floyd, Evan L.; Sapag, Karim; Oh, Jonghwa; Lungu, Claudiu T.

    2014-01-01

    Many techniques exist to measure airborne volatile organic compounds (VOCs), each with differing advantages; sorbent sampling is compact, versatile, has good sample stability, and is the preferred technique for collecting VOCs for hygienists. Development of a desorption technique that allows multiple analyses per sample (similar to chemical desorption) with enhanced sensitivity (similar to thermal desorption) would be helpful to field hygienists. In this study, activated carbon (AC) and single-walled carbon nanotubes (SWNT) were preloaded with toluene vapor and partially desorbed with light using a common 12-V DC, 50-W incandescent/halogen lamp. A series of experimental chamber configurations were explored starting with a 500-ml chamber under static conditions, then with low ventilation and high ventilation, finally a 75-ml high ventilation chamber was evaluated. When preloaded with toluene and irradiated at the highest lamp setting for 4min, AC desorbed 13.9, 18.5, 23.8, and 45.9% of the loaded VOC mass, in each chamber configuration, respectively; SWNT desorbed 25.2, 24.3, 37.4, and 70.5% of the loaded VOC mass, respectively. SWNT desorption was significantly greater than AC in all test conditions (P = 0.02–<0.0001) demonstrating a substantial difference in sorbent performance. When loaded with 0.435mg toluene and desorbed at the highest lamp setting for 4min in the final chamber design, the mean desorption for AC was 45.8% (39.7, 52.0) and SWNT was 72.6% (68.8, 76.4) (mean represented in terms of 95% confidence interval). All desorption measurements were obtained using a field grade photoionization detector; this demonstrates the potential of using this technique to perform infield prescreening of VOC samples for immediate exposure feedback and in the analytical lab to introduce sample to a gas chromatograph for detailed analysis of the sample. PMID:25016598

  6. Method to produce large, uniform hollow spherical shells

    DOEpatents

    Hendricks, Charles D.

    1985-01-01

    Large, uniform hollow spherical shells are produced by forming uniform size drops of heat decomposable or vaporizable material, evaporating the drops to form dried particles, coating the dried particles with a layer of shell forming material, and heating the composite particles to melt the outer layer and decompose or vaporize the inner particle to form an expanding inner gas bubble which expands the outer layer. By cycling the temperature and pressure on the hollow shells, spherical shells with uniform walls are produced.

  7. Sound Transmission through Two Concentric Cylindrical Sandwich Shells

    NASA Technical Reports Server (NTRS)

    Tang, Yvette Y.; Silcox, Richard J.; Robinson, Jay H.

    1996-01-01

    This paper solves the problem of sound transmission through a system of two infinite concentric cylindrical sandwich shells. The shells are surrounded by external and internal fluid media and there is fluid (air) in the annular space between them. An oblique plane sound wave is incident upon the surface of the outer shell. A uniform flow is moving with a constant velocity in the external fluid medium. Classical thin shell theory is applied to the inner shell and first-order shear deformation theory is applied to the outer shell. A closed form for transmission loss is derived based on modal analysis. Investigations have been made for the impedance of both shells and the transmission loss through the shells from the exterior into the interior. Results are compared for double sandwich shells and single sandwich shells. This study shows that: (1) the impedance of the inner shell is much smaller than that of the outer shell so that the transmission loss is almost the same in both the annular space and the interior cavity of the shells; (2) the two concentric sandwich shells can produce an appreciable increase of transmission loss over single sandwich shells especially in the high frequency range; and (3) design guidelines may be derived with respect to the noise reduction requirement and the pressure in the annular space at a mid-frequency range.

  8. Resonant enhancement of a single attosecond pulse in a gas medium by a time-delayed control field

    NASA Astrophysics Data System (ADS)

    Chu, Wei-Chun; Lin, C. D.

    2012-10-01

    An optical coherent control scheme has been proposed and theoretically investigated where an extreme ultraviolet single attosecond pulse (SAP) propagates through dense helium gas dressed by a time-delayed femtosecond laser pulse. The laser pulse couples the 2s2p(1P) and 2s2(1S) autoionizing states when the SAP excites the 2s2p state. After going through the gas, the spectral and temporal profiles of the SAP are strongly distorted. A narrowed but enhanced spike in the spectrum shows up for specific intensities and time delays of the laser, which exemplifies the control of a broadband photon wave packet by an ultrashort dressing field for the first time. We analyse the photon and electron dynamics and determine the dressing condition that maximizes this enhancement. The result demonstrates new possibilities of attosecond optical control.

  9. Development of Metal-impregnated Single Walled Carbon Nanotubes for Toxic Gas Contaminant Control in Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Cinke, Martin; Li, Jing; Chen, Bin; Wignarajah, Kanapathipillai; Pisharody, Suresh A.; Fisher, John W.; Delzeit, Lance; Meyyappan, Meyya; Partridge, Harry; Clark, Kimberlee

    2003-01-01

    The success of physico-chemical waste processing and resource recovery technologies for life support application depends partly on the ability of gas clean-up systems to efficiently remove trace contaminants generated during the process with minimal use of expendables. Highly purified metal-impregnated carbon nanotubes promise superior performance over conventional approaches to gas clean-up due to their ability to direct the selective uptake gaseous species based both on the nanotube s controlled pore size, high surface area, and ordered chemical structure that allows functionalization and on the nanotube s effectiveness as a catalyst support material for toxic contaminants removal. We present results on the purification of single walled carbon nanotubes (SWCNT) and efforts at metal impregnation of the SWCNT's.

  10. An Equation of State study of a Boron Nitride rubber composite using a Single Stage Gas Gun

    NASA Astrophysics Data System (ADS)

    Taylor, Peter; Keightley, Peter

    2007-06-01

    The equation of state of a Boron Nitride powder / Neoprene / Polythene composite has been determined experimentally up to 5GPa using a single stage Helium gas gun. The newly commissioned gun operates using a fast acting gas valve breech, and is capable of launching a 65mm diameter flyer at up to 1km/s. A series of 1D plate impact experiments has been employed using a shock reverberation or ring-up technique in which the sample is sandwiched between layers of a higher shock impedence material. Manganin stress gauges are used to measure the stress levels and shock arrival times as the shocks reverberate within the sample layer. The Hugoniot has been determined from the measured stress and shock velocity at several impact velocities for the first shock. Subsequent reflected shocks within the sample have been measured and used to determine off Hugoniot states and hence Gruniesen Gamma in order to derive the equation of state.

  11. Glass shell manufacturing in space

    NASA Technical Reports Server (NTRS)

    Nolen, R. L., Jr.; Ebner, M. A.; Downs, R. L.

    1980-01-01

    A heat transfer model was developed that mathematically describes the heating and calculates the thermal history of a gel particle in free-fall through the furnace. The model parameters that greatly affect the calculations were found to be gel particle mass, geometry, specific heat, and furnace gas. Empirical testing of the model has commenced. The code calculations and the initial empirical testing results both indicate that the gel-to-shell transformation occurs early and rapidly in the thermal history of the gel particle, and that for current work the heat transfer rate is not a limitation in shell production.

  12. Ceramics for the advanced automotive gas turbine engine - A look at a single shaft design

    NASA Technical Reports Server (NTRS)

    Nosek, S. M.

    1978-01-01

    A single-shaft regenerative design with a single-stage radial turbine is analyzed in terms of achievable fuel economy for the cases of both limited and unlimited turbine tip speed and regenerator inlet temperature. The 100-hp engine for a 3500-lb automobile is designed to use gasoline. Fuel economy data and operating parameters are presented for different values of turbine inlet temperatures, and turbine stress estimates and ceramic design stress estimates are discussed.

  13. Analysis of regenerated single-shaft ceramic gas-turbine engines and resulting fuel economy in a compact car

    NASA Technical Reports Server (NTRS)

    Klann, J. L.; Tew, R. C., Jr.

    1977-01-01

    Ranges in design and off-design operating conditions of an advanced gas turbine and their effects on fuel economy were analyzed. The assumed engine incorporated a single stage radial flow turbine and compressor with fixed geometry. Fuel economies were calculated over the composite driving cycle with gasoline as the fuel. At a constant turbine-inlet temperature, with a regenerator sized for a full power effectiveness the best fuel economies ranged from 11.1 to 10.2 km/liter (26.2 to 22.5 mpg) for full power turbine tip speeds of 770 to 488m/sec (2530 to 1600ft/sec), respectively.

  14. Gas-phase catalysis by atomic and cluster metal ions: the ultimate single-site catalysts.

    PubMed

    Böhme, Diethard K; Schwarz, Helmut

    2005-04-15

    Gas-phase experiments with state-of-the-art techniques of mass spectrometry provide detailed insights into numerous elementary processes. The focus of this Review is on elementary reactions of ions that achieve complete catalytic cycles under thermal conditions. The examples chosen cover aspects of catalysis pertinent to areas as diverse as atmospheric chemistry and surface chemistry. We describe how transfer of oxygen atoms, bond activation, and coupling of fragments can be mediated by atomic or cluster metal ions. In some cases truly unexpected analogies of the idealized gas-phase ion catalysis can be drawn with related chemical transformations in solution or the solid state, and so improve our understanding of the intrinsic operation of a practical catalyst at a strictly molecular level.

  15. Combustion Dynamics Behavior in a Single-Element Lean Direct Injection (LDI) Gas Turbine Combustor

    DTIC Science & Technology

    2014-06-01

    Technical Paper 3. DATES COVERED (From - To) June 2014- July 2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER In-House Combustion Dynamics Behavior in a...excited combustion dynamics in a model configuration of a lean direct injection (LDI) gas turbine combustor is described. Incoming air temperature and...detailed study of the underlying combustion dynamics mechanisms. First, hydrodynamic modes are investigated by conducting the simulation with an

  16. Enhancement of Sublimation of Single Graphene Layer by Interacting with Gas Molecules in Rarefied Environment

    NASA Astrophysics Data System (ADS)

    Murugesan, Ramki; Park, Jae Hyun

    2014-11-01

    Graphene has excellent mechanical properties. One of them is the resistance to high temperature environment. Since the sublimation temperature of graphene is over 4500 K, it has been used for diverse high temperature applications in order to protect the system. In this study, using extensive molecular dynamics simulations, we show that the sublimation of graphene could be enhanced (occurs at the lower temperature) by interacting with the gas molecules. With increase in temperature, the bonds in graphene becomes so sensitive to interact with the incoming gas molecules. When the temperature is low, the graphene is stable to the impingement of gas molecules: The light H2 gases are stick to the graphene surface and remains being attached while the heavy CO2 and H2O are bounced back from the surface. However, at high temperature H2 gases are absorbed on the graphene and destroy the C -C bonds by forming C -H bonds. The local breakage of bond at the impingement spot spreads the entire graphene soon, causing a complete sublimation. Even though the heavy CO2 and H2O molecules also break the C -C bonds at high temperature,but their impingement effect is localized and the breakage does not propagate over the entire surface. This research was supported by Agency for Defence Development (ADD).

  17. Bombardment of gas molecules on single graphene layer at high temperature

    SciTech Connect

    Murugesan, Ramki; Park, Jae Hyun; Ha, Dong Sung

    2014-12-09

    Graphite is widely used as a material for rocket-nozzle inserts due to its excellent thermo-physical properties as well as low density. During the operation of rockets, the surface of the graphite nozzle is subjected to very high heat fluxes and the undesirable erosion of the surface occurs due to the bombardment of gas molecules with high kinetic energy, which causes a significant reduction of nozzle performance. However, the understanding and quantification of such bombardment is not satisfactory due to its complexity: The bond breaking-forming happens simultaneously for the carbon atoms of graphene, some gas molecules penetrate through the surface, some of them are reflected from the surface, etc. In the present study, we perform extensive molecular dynamics (MD) simulations to examine the bombardment phenomena in high temperature environment (several thousand Kelvin). Advanced from the previous studies that have focused on the bombardment by light molecules (e.g., H{sub 2}), we will concentrate on the impact by realistic molecules (e.g., CO{sub 2} and H{sub 2}O). LAMMPS is employed for the MD simulations with NVE ensemble and AIREBO potential for graphene. The molecular understanding of the interaction between graphene and highly energetic gas molecules will enable us to design an efficient thermo-mechanical protection system.

  18. Bombardment of gas molecules on single graphene layer at high temperature

    NASA Astrophysics Data System (ADS)

    Murugesan, Ramki; Park, Jae Hyun; Ha, Dong Sung

    2014-12-01

    Graphite is widely used as a material for rocket-nozzle inserts due to its excellent thermo-physical properties as well as low density. During the operation of rockets, the surface of the graphite nozzle is subjected to very high heat fluxes and the undesirable erosion of the surface occurs due to the bombardment of gas molecules with high kinetic energy, which causes a significant reduction of nozzle performance. However, the understanding and quantification of such bombardment is not satisfactory due to its complexity: The bond breaking-forming happens simultaneously for the carbon atoms of graphene, some gas molecules penetrate through the surface, some of them are reflected from the surface, etc. In the present study, we perform extensive molecular dynamics (MD) simulations to examine the bombardment phenomena in high temperature environment (several thousand Kelvin). Advanced from the previous studies that have focused on the bombardment by light molecules (e.g., H2), we will concentrate on the impact by realistic molecules (e.g., CO2 and H2O ). LAMMPS is employed for the MD simulations with NVE ensemble and AIREBO potential for graphene. The molecular understanding of the interaction between graphene and highly energetic gas molecules will enable us to design an efficient thermo-mechanical protection system.

  19. Geologic parameters controlling natural gas production from single, deeply buried coal reservoir

    SciTech Connect

    Decker, D.

    1986-05-01

    Methane occluded in coal reservoirs is being commercially produced in the Appalachian, Warrior, San Juan, and Piceance basins. Of these, the Piceance basin, with an estimated 100 tcf of coal-bed methane, represents the largest coal-bed methane resource in the US. Exploration efforts applied to this vast resource have been hampered by lack of appropriate exploration, drilling, completion, stimulation, and production methods. The Deep Coal Seam project sponsored by the Gas Research Institute and operated by Resource Enterprises, Inc., at the Red Mountain site, Mesa County, Colorado, was established to develop, improve, evaluate, and communicate the technology required to produce gas from deeply buried coal reservoirs. Regional geologic studies have established the Red Mountain site as representing most of the coal-bed methane resource within the Piceance basin. The project is focused on the D coal seam, belonging to the Cameo coal group of the Williams Fork formation, Upper Cretaceous Mesaverde Group. The D coal seam thickness ranges from 16 to 20 ft (5 to 6 m) throughout the site, with an average drilling depth of 5500 ft (1700 m). This coal seam is medium-volatile bituminous in rank, with an average gas content of 250 standard ft/sup 3//ton (8 standard cm/sup 3//g).

  20. Synthesis and Gas Sensing Properties of Single La-Doped SnO₂ Nanobelts.

    PubMed

    Wu, Yuemei; Zhang, Heng; Liu, Yingkai; Chen, Weiwu; Ma, Jiang; Li, Shuanghui; Qin, Zhaojun

    2015-06-16

    Single crystal SnO2 nanobelts (SnO2 NBs) and La-SnO2 nanobelts (La-SnO2 NBs) were synthesized by thermal evaporation. Both a single SnO2 NB sensor and a single La-SnO2 NB sensor were developed and their sensing properties were investigated. It is found that the single La-SnO2 NB sensor had a high sensitivity of 8.76 to ethanediol at a concentration of 100 ppm at 230 °C, which is the highest sensitivity of a single SnO2 NB to ethanediol among three kinds of volatile organic (VOC) liquids studied, including ethanediol, ethanol, and acetone. The La-SnO2 NBs sensor also exhibits a high sensitivity, good selectivity and long-term stability with prompt response time to ethanediol. The mechanism behind the enhanced sensing performance of La-doped SnO2 nanobelts is discussed.

  1. Production-data analysis of single-phase (gas) coalbed-methane wells

    SciTech Connect

    Clarkson, C.R.; Bustin, R.M.; Seidle, J.P.

    2007-06-15

    The current work illustrates how single-well production-data-analysis (PDA) techniques, such as type curve, flowing material balance (FMB), and pressure-transient (PT) analysis, may be altered to analyze single-phase CBM wells. Examples of how reservoir inputs to the PDA techniques and subsequent calculations are modified to account for CBM-reservoir behavior are given. This paper demonstrates, by simulated and field examples, that reasonable reservoir and stimulation estimates can be obtained from PDA of CBM reservoirs only if appropriate reservoir inputs (i.e., desorption compressibility, fracture porosity) are used in the analysis. As the field examples demonstrate, type-curve, FMB, and PT analysis methods for PDA are not used in isolation for reservoir-property estimation, but rather as a starting point for single-well and multiwell reservoir simulation, which is then used to history match and forecast CBM-well production (e.g., for reserves assignment). To study the effects of permeability anisotropy upon production, a 2D, single-phase, numerical CBM-reservoir simulator was constructed to simulate single-well production assuming various permeability-anisotropy ratios. Only large permeability ratios ({lt} 16:1) appear to have a significant effect upon single-well production characteristics. Multilayer reservoir characteristics may also be observed with CBM reservoirs because of vertical heterogeneity, or in cases where the coals are commingled with conventional (sandstone) reservoirs. In these cases, the type-curve, FMB, and PT analysis techniques are difficult to apply with confidence. Methods and tools for analyzing multilayer CBM (plus sand) reservoirs are presented. Using simulated and field examples, it is demonstrated that unique reservoir properties may be assigned to individual layers from commingled (multilayer) production in the simple two-layer case.

  2. Following electron impact excitations of Rn, Ra, Th, U and Pu single atom L sub-shells ionization cross section calculations by using Lotz's equation

    NASA Astrophysics Data System (ADS)

    Ayinol, M.; Aydeniz, D.

    2016-03-01

    L shell ionization cross section and Li subshells ionization cross sections of Rn, Ra, Th, U, Pu atoms calculated. For each of atoms, ten different electron impact energy values (Eo) are used. Calculations carried out by using Lotz equation in Matlab. First, calculations done for non-relativistic case by using non-relativistic Lotz equation then repeated with relativistic Lotz equation. σL total and σLi(i = 1,2,3) subshells ionisation cross section values obtained for Eo values in the energy range of ELi shell ionization threshold energy, σL total and σLi (i = 1,2,3) are increasing rapidly with Eo. For a fixed Eo = 3.ELi), while Z increases from 86

  3. Quantification of the Gas Mass Emitted During a Single Explosion on Stromboli with the SO2 Camera

    NASA Astrophysics Data System (ADS)

    Mori, T.; Burton, M.; Wright, T. E.

    2007-12-01

    The recent development of the SO2 camera is a powerful new tool for volcanologists that allows quantitative imaging of SO2 amounts within volcanic plumes. Such SO2 images are information-rich compared to traditional measurements by COSPEC or compact UV spectrometer systems which measure the equivalent of one pixel in an SO2 image. Furthermore, using time-series of SO2 images, we can examine short- lived events on the order of seconds and quantitatively constrain wind speed, the greatest source of error in flux determination. The new capabilities offered by the SO2 camera herald a major step forward for understanding degassing processes and therefore civil defence. On October 3 and 4, 2006, we performed SO2 imaging measurements at Stromboli volcano, Italy. The SO2 camera was placed on the north-eastern flank of the volcano about 2.4 km from the summit craters and recorded SO2 images with a time-interval of 5.0 seconds on Oct. 3 and 3.2 seconds on Oct. 4, respectively. More than 1500 SO2 plume images were collected. Major variations in SO2 flux were observed over a timescale of a few minutes and several peaks were seen. By relating the major increases of the flux with a movie of the SO2 plume images, we can conclude that the main cause of these variations was strombolian explosions. In the afternoon of Oct. 3, we took the SO2 camera to the summit of the volcano. The aim of the measurements was to quantify the amount of SO2 emitted during a single explosion. The SO2 camera was set up 400 m north of the craters and a single UV band-pass filter (Center wavelength: 310 nm, HWHM 10 nm) was used in the measurements. We obtained more than 600 plume images with time interval between frames of ~2 seconds. By analyzing the SO2 images, we could separate several explosive events from the background quiescent degassing. The amount of SO2 emitted by a single explosion was 15 - 40 kg which corresponds to approximate total gas mass of 350 - 900 kg. Assuming that the gas slug

  4. Single target sputter deposition of alloy nanoparticles with adjustable composition via a gas aggregation cluster source.

    PubMed

    Vahl, Alexander; Strobel, Julian; Reichstein, Wiebke; Polonskyi, Oleksandr; Strunskus, Thomas; Kienle, Lorenz; Faupel, Franz

    2017-04-28

    Alloy nanoparticles with variable compositions add a new dimension to nanoscience and have many applications. Here we suggest a novel approach for the fabrication of variable composition alloy nanoparticles that is based on a Haberland type gas aggregation cluster source with a custom-made multicomponent target for magnetron sputtering. The approach, which was demonstrated here for gold-rich AgAu nanoparticles, combines a narrow nanoparticle size distribution with in operando variation of composition via the gas pressure as well as highly efficient usage of target material. The latter is particularly attractive for precious metals. Varying argon pressure during deposition, we achieved in operando changes of AgAu alloy nanoparticle composition of more than 13 at%. The alloy nanoparticles were characterized by x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy. The characteristic plasmon resonances of multilayer nanoparticle composites were analyzed by UV-vis spectroscopy. Tuning of the number of particles per unit area (particle densities) within individual layers showed an additional degree of freedom to tailor the optical properties of multilayer nanocomposites. By extension of this technique to more complex systems, the presented results are expected to encourage and simplify further research based on plasmonic multi-element nanoparticles. The present method is by no means restricted to plasmonics or nanoparticle based applications, but is also highly relevant for conventional magnetron sputtering of alloys and can be extended to in operando control of alloy concentration by magnetic field.

  5. Carbon isotopes in mollusk shell carbonates

    NASA Astrophysics Data System (ADS)

    McConnaughey, Ted A.; Gillikin, David Paul

    2008-10-01

    Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod shell carbonates. Land snails construct their shells mainly from respired CO2, and shell δ13C reflects the local mix of C3 and C4 plants consumed. Shell δ13C is typically >10‰ heavier than diet, probably because respiratory gas exchange discards CO2, and retains the isotopically heavier HCO3 -. Respired CO2 contributes less to the shells of aquatic mollusks, because CO2/O2 ratios are usually higher in water than in air, leading to more replacement of respired CO2 by environmental CO2. Fluid exchange with the environment also brings additional dissolved inorganic carbon (DIC) into the calcification site. Shell δ13C is typically a few ‰ lower than ambient DIC, and often decreases with age. Shell δ13C retains clues about processes such as ecosystem metabolism and estuarine mixing. Ca2+ ATPase-based models of calcification physiology developed for corals and algae likely apply to mollusks, too, but lower pH and carbonic anhydrase at the calcification site probably suppress kinetic isotope effects. Carbon isotopes in biogenic carbonates are clearly complex, but cautious interpretation can provide a wealth of information, especially after vital effects are better understood.

  6. Modeling and simulation of plasma gas flow driven by a single nanosecond-pulsed dielectric barrier discharge

    NASA Astrophysics Data System (ADS)

    Xu, S. Y.; Cai, J. S.; Li, J.

    2016-10-01

    A simplified (7 species and 9 processes) plasma kinetic model is proposed to investigate the mechanism of the plasma aerodynamic actuation driven by nanosecond-pulsed dielectric barrier discharge (NS-DBD). The governing equations include conservation equations for each species, the Poisson equation for the electric potential, and Navier-Stokes equations for the gas dynamic flow. Numerical simulations of plasma discharge and flow actuation on NS-DBD plasma actuators have been carried out. Key discharge characteristics and the responses of the quiescent air were reproduced and compared to those obtained in experiments and numerical simulations. Results demonstrate that the reduced plasma kinetic model is able to capture the dominant species and reactions to predict the actuation in complicated hydrodynamics. For the one-dimensional planar and two-dimensional symmetric NS-DBD, the forming of the sheath collapse is mainly due to the charge accumulation and secondary emission from the grounded electrode. Rapid species number density rise and electric field drop occur at the edge of the plasma sheath, where the space charge density gradient peaks. For the aerodynamic actuation with typical asymmetry electrodes, discharge characteristics have a core area on the right edge of the upper electrode, where the value can be much higher. The formation and propagation of the compression waves generated through rapid heating have also been performed and compared to those measured in a recent experiment. Energy release leads to gas expansion and forms a cylindrical shock wave, centering at the upper electrode tip with low gas acceleration. For the present single pulsed 12 kV case, the mean temperature of gas heating reaches about 575 K at 1 μs and decreases to about 460 K at 10 μs.

  7. The ultimate step towards a tailored engineering of core@shell and core@shell@shell nanoparticles.

    PubMed

    Llamosa, D; Ruano, M; Martínez, L; Mayoral, A; Roman, E; García-Hernández, M; Huttel, Y

    2014-11-21

    Complex core@shell and core@shell@shell nanoparticles are systems that combine the functionalities of the inner core and outer shell materials together with new physico-chemical properties originated by their low (nano) dimensionality. Such nanoparticles are of prime importance in the fast growing field of nanotechnology as building blocks for more sophisticated systems and a plethora of applications. Here, it is shown that although conceptually simple a modified gas aggregation approach allows the one-step generation of well-controlled complex nanoparticles. In particular, it is demonstrated that the atoms of the core and the shell of the nanoparticles can be easily inverted, avoiding intrinsic constraints of chemical methods.

  8. Ceramics for the advanced automotive gas turbine engine: A look at a single shaft design

    NASA Technical Reports Server (NTRS)

    Nosek, S. M.

    1977-01-01

    The results of a preliminary analysis of a single shaft regenerative design with a single stage radial turbine are presented to show the fuel economy that can be achieved at high turbine inlet temperatures, with this particular advanced design, if the turbine tip speed and regenerator inlet temperature are not limited. The engine size was 100 hp for application to a 3500 lb auto. The fuel economy was analyzed by coupling the engine to the auto through a continuously variable speed-ratio transmission and operating the system at constant turbine inlet temperature over the Composite Driving Cycle. The fuel was gasoline and the analysis was for a 85 F day. With a turbine inlet temperature of 2500 F the fuel economy was 26.2 mpg, an improvement of 18 percent over that of 22.3 mpg with a turbine inlet temperature of 1900 F. The turbine tip speed needed for best economy with the 2500 F engine was 2530 ft/sec. The regenerator temperature was approximately 2200 F at idle. Disk stresses were estimated for one single stage radial turbine and two two-stage radial-axial turbines and compared with maximum allowable stress curves estimated for a current ceramic material. Results show a need for higher Weibull Modulus, higher strength ceramics.

  9. Contact Forces between Single Metal Oxide Nanoparticles in Gas-Phase Applications and Processes

    PubMed Central

    2017-01-01

    In this work we present a comprehensive experimental study to determine the contact forces between individual metal oxide nanoparticles in the gas-phase using atomic force microscopy. In addition, we determined the amount of physisorbed water for each type of particle surface. By comparing our results with mathematical models of the interaction forces, we could demonstrate that classical continuum models of van der Waals and capillary forces alone cannot sufficiently describe the experimental findings. Rather, the discrete nature of the molecules has to be considered, which leads to ordering at the interface and the occurrence of solvation forces. We demonstrate that inclusion of solvation forces in the model leads to quantitative agreement with experimental data and that tuning of the molecular order by addition of isopropanol vapor allows us to control the interaction forces between the nanoparticles. PMID:28186771

  10. Shock Ignition in Non-Cryogenic Metal-Gas Targets on the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Perkins, L. John; Cerjan, C.; Smalyuk, V.; Bailey, D.; Comley, A.; Garbett, W.; McKenty, P.; Cheng, B.

    2011-10-01

    Shock ignition offers the possibility of volumetric ignition and burn in single-shell, room-temperature gas targets on the National Ignition Facility. We are investigating whether the high fusion energy gains potentially available with shock ignition in cryogenic DT targets on NIF (L.J.Perkins et al, PRL 103 (2009)) can be traded for modest gains and yields in such platforms. If so, being non-cryogenic with simple single-shell construction and medium-pressure gas fill, they should easier to field and diagnose. The targets are characterized by a thick, graded-density Be-Au ablator-pusher shell with low in-flight-aspect-ratios. Because the high-Z Au shell reflects Bremsstrahlung, such targets are capable of volumetric ignition at temperatures of around 4 keV with low shell velocities around 1.5e7cm/s. Gas targets are inherently low gain (<=10) so they are probably not IFE relevant. The ultimate performance will be determined by degree and control of high-Z mix in the gas. Simulations indicate that we can potentially trade fusion yield for good ignition fall-line behavior by tuning gas pressure and shock launch time. This work performed under the auspices of U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

  11. Double Shell Plans and First Results from Outer Shell Keyhole Experiments

    NASA Astrophysics Data System (ADS)

    Montgomery, D. S.; Merritt, E. C.; Daughton, W. S.; Loomis, E. N.; Wilson, D. C.; Dodd, E. S.; Kline, J. L.; Batha, S. H.; Robey, H. F.

    2016-10-01

    Double-shells are an alternative approach to achieving indirect drive ignition on NIF. These targets consist of a low-Z ablatively-driven outer shell that impacts a high-Z inner shell filled with DT fuel. In contrast to single-shell designs, double-shell targets burn the fuel via volume ignition, albeit with a lower gain. While double-shell capsules are complicated to fabricate, their design includes several beneficial metrics such as a low convergence pusher (C.R. < 10), low implosion speed (250 km/s), a simple few-ns laser drive in a vacuum hohlraum, less sensitivity to hohlraum asymmetries, and low expected laser-plasma instabilities. We describe plans for developing double shell capsule implosions on NIF, and discuss challenges as well as uncertainties and trade-offs in the physics issues compared to single-shells, such as sensitivity to hard x-ray preheat of the inner shell. First experimental results measuring hard x-ray preheat, shock breakout and shock symmetry from outer-shell experiments using the NIF Keyhole platform will be presented. Work performed under the auspices of DOE by LANL under contract DE-AC52-06NA25396.

  12. Offshore UK; Shell starts Galleon field pre-drilling

    SciTech Connect

    Not Available

    1993-01-01

    Shell U.K. Exploration and Production (Shell), acting as operator for a consortium of companies, has described plans for the two-phase development of Galleon gas field, located 50 miles from the Shell/Esso gas processing plant at Bacton, Norfolk, in 82 ft of water. The field has estimated reserves of 1.4 Tcf. Phase 1 development will cost [Brit pounds]300 million ($500 million); and first production is expected in late 1994. British Gas has agreed to purchase at least Phase 1 gas. Shell will be the operator for the development. A preliminary costsharing arrangement has been agreed to by the co-venturers to bridge the period until equities are determined. The consortium comprises Shell and Esso, with 40% each, and Conoco (U.K.) Ltd. and Oryx U.K. Energy Co., each with 10%. The field is located in Shell/Esso Blocks 48/14, 19a and 20a, and Conoco/Oryx Block 48/15a. Galleon will be the sixth gas field to be developed in the Southern North Sea by Shell, the operator for Shell and Esso. It will be the third field in the Sole Pit area, where total reserves found by Shell/Esso are about 3.0 Tcf.

  13. Retained gas inventory comparison

    SciTech Connect

    BARTON, W.B.

    1999-05-18

    Gas volume data derived from four different analytical methods were collected and analyzed for comparison to volumes originally used in the technical basis for the Basis for Interim Operations (BIO). The original volumes came from Hodgson (1996) listed in the reference section of this document. Hodgson (1996) screened all 177 single and double-shell tanks for the presence of trapped gas in waste via two analytical methods: Surface Level Rise (SLR), and Barometric Pressure Effect (BPE). More recent gas volume projections have been calculated using different analytical techniques along with updates to the parameters used as input to the SLR and BPE models. Gas volumes derived from new analytical instruments include those as measured by the Void Fraction Instrument (VFI) and Retained Gas Sampler (RGS). The results of this comparison demonstrate that the original retained gas volumes of Hodgson (1996) used as a technical basis in developing the BIO were conservative, and were conservative from a safety analysis standpoint. These results represent only comparisons to the original reported volumes using the limited set of newly acquired data that is available.

  14. Direct comparison of fatty acid ratios in single cellular lipid droplets as determined by comparative Raman spectroscopy and gas chromatography.

    PubMed

    Schie, Iwan W; Nolte, Lena; Pedersen, Theresa L; Smith, Zach; Wu, Jian; Yahiatène, Idir; Newman, John W; Huser, Thomas

    2013-11-07

    Cellular lipid droplets are the least studied and least understood cellular organelles in eukaryotic and prokaryotic cells. Despite a significant body of research studying the physiology of lipid droplets it has not yet been possible to fully determine the composition of individual cellular lipid droplets. In this paper we use Raman spectroscopy on single cellular lipid droplets and least-squares fitting of pure fatty acid spectra to determine the composition of individual lipid droplets in cells after treatment with different ratios of oleic and palmitic acid. We validate the results of the Raman spectroscopy-based single lipid droplet analysis with results obtained by gas chromatography analysis of millions of cells, and find that our approach can accurately predict the relative amount of a specific fatty acid in the lipid droplet. Based on these results we show that the fatty acid composition in individual lipid droplets is on average similar to that of all lipid droplets found in the sample. Furthermore, we expand this approach to the investigation of the lipid composition in single cellular peroxisomes. We determine the location of cellular peroxisomes based on two-photon excitation fluorescence (TPEF) imaging of peroxisomes labeled with the green fluorescent protein, and successive Raman spectroscopy of peroxisomes. We find that in some cases peroxisomes can produce a detectable CARS signal, and that the peroxisomal Raman spectra exhibit an oleic acid-like signature.

  15. Low-temperature GaN growth on silicon substrates by single gas-source epitaxy and photo-excitation

    SciTech Connect

    Trivedi, R.A.; Tolle, J.; Chizmeshya, A.V.G.; Roucka, R.; Ritter, Cole; Kouvetakis, J.; Tsong, I.S.T.

    2005-08-15

    We report a unique low-temperature growth method for epitaxial GaN on Si(111) substrates via a ZrB{sub 2}(0001) buffer layer. The method utilizes the decomposition of a single gas-source precursor (D{sub 2}GaN{sub 3}){sub 3} on the substrate surface to form GaN. The film growth process is further promoted by irradiation of ultraviolet light to enhance the growth rate and ordering of the film. The best epitaxial film quality is achieved at a growth temperature of 550 deg. C with a growth rate of 3 nm/min. The films exhibit intense photoluminescence emission at 10 K with a single peak at 3.48 eV, indicative of band-edge emission for a single-phase hexagonal GaN film. The growth process achieved in this study is compatible with low Si processing temperatures and also enables direct epitaxy of GaN on ZrB{sub 2} in contrast to conventional metalorganic chemical vapor deposition based approaches.

  16. Gas-Phase Synthesis of Singly and Multiply Charged Polyoxovanadate Anions Employing Electrospray Ionization and Collision Induced Dissociation

    NASA Astrophysics Data System (ADS)

    Al Hasan, Naila M.; Johnson, Grant E.; Laskin, Julia

    2013-09-01

    Electrospray ionization mass spectrometry (ESI-MS) combined with in-source fragmentation and tandem mass spectrometry (MS/MS) experiments were used to generate a wide range of singly and multiply charged vanadium oxide cluster anions including VxOy n- and VxOyCln- ions (x = 1-14, y = 2-36, n = 1-3), protonated clusters, and ligand-bound polyoxovanadate anions. The cluster anions were produced by electrospraying a solution of tetradecavanadate, V14O36Cl(L)5 (L = Et4N+, tetraethylammonium), in acetonitrile. Under mild source conditions, ESI-MS generates a distribution of doubly and triply charged VxOyCln- and VxOyCl(L)(n-1)- clusters predominantly containing 14 vanadium atoms as well as their protonated analogs. Accurate mass measurement using a high-resolution LTQ/Orbitrap mass spectrometer (m/Δm = 60,000 at m/z 410) enabled unambiguous assignment of the elemental composition of the majority of peaks in the ESI-MS spectrum. In addition, high-sensitivity mass spectrometry allowed the charge state of the cluster ions to be assigned based on the separation of the major from the much less abundant minor isotope of vanadium. In-source fragmentation resulted in facile formation of smaller VxOyCl(1-2)- and VxOy (1-2)- anions. Collision-induced dissociation (CID) experiments enabled systematic study of the gas-phase fragmentation pathways of the cluster anions originating from solution and from in-source CID. Surprisingly simple fragmentation patterns were obtained for all singly and doubly charged VxOyCl and VxOy species generated through multiple MS/MS experiments. In contrast, cluster anions originating directly from solution produced comparatively complex CID spectra. These results are consistent with the formation of more stable structures of VxOyCl and VxOy anions through low-energy CID. Furthermore, our results demonstrate that solution-phase synthesis of one precursor cluster anion combined with gas-phase CID is an efficient approach for the top-down synthesis of a

  17. DYNAMIC RESPONSE OF SINGLE CRYSTALLINE COPPER SUBJECTED TO QUASI-ISENTROPIC, GAS-GUN DRIVEN LOADING

    SciTech Connect

    Jarmakani, H; Mc Naney, J M; Schneider, M S; Cao, B Y; Orlikowski, D; Nguyen, J H; Kad, B; Meyers, M A

    2005-11-02

    A transmission electron microscopy study of quasi-isentropic gas-gun loading (peak pressures between 18 GPa and 52 GPa) of [001] monocrystalline copper was carried out. The defect substructures at these different pressures were analyzed. Current experimental evidence suggests a deformation substructure that transitions from slip to twinning, where twinning occurs at the higher pressures ({approx}52 GPa), and heavily dislocated laths and dislocation cells take place at the intermediate and lower pressures. Evidence of stacking faults at the intermediate pressures was also found. Dislocation cell sizes decreased with increasing pressure and increased with distance away from the surface of impact. The results from the quasi-isentropic experiments are compared with that of flyer-plate and laser shock experiments carried out by Cao et al. [1] and Schneider et al. [2], respectively. The Preston-Tonks-Wallace and Zerilli-Armstrong constitutive descriptions are used to model both isentropic and shock compression experiments and predict the pressure at which the slip-twinning transition occurs in both cases. Both models predict a higher transition for isentropic then for shock experiments, and indeed, that twinning should not take place in the ICE experiments at the pressures investigated.

  18. The 1257 Samalas eruption (Lombok, Indonesia): the single greatest stratospheric gas release of the Common Era.

    PubMed

    Vidal, Céline M; Métrich, Nicole; Komorowski, Jean-Christophe; Pratomo, Indyo; Michel, Agnès; Kartadinata, Nugraha; Robert, Vincent; Lavigne, Franck

    2016-10-10

    Large explosive eruptions inject volcanic gases and fine ash to stratospheric altitudes, contributing to global cooling at the Earth's surface and occasionally to ozone depletion. The modelling of the climate response to these strong injections of volatiles commonly relies on ice-core records of volcanic sulphate aerosols. Here we use an independent geochemical approach which demonstrates that the great 1257 eruption of Samalas (Lombok, Indonesia) released enough sulphur and halogen gases into the stratosphere to produce the reported global cooling during the second half of the 13th century, as well as potential substantial ozone destruction. Major, trace and volatile element compositions of eruptive products recording the magmatic differentiation processes leading to the 1257 eruption indicate that Mt Samalas released 158 ± 12 Tg of sulphur dioxide, 227 ± 18 Tg of chlorine and a maximum of 1.3 ± 0.3 Tg of bromine. These emissions stand as the greatest volcanogenic gas injection of the Common Era. Our findings not only provide robust constraints for the modelling of the combined impact of sulphur and halogens on stratosphere chemistry of the largest eruption of the last millennium, but also develop a methodology to better quantify the degassing budgets of explosive eruptions of all magnitudes.

  19. The 1257 Samalas eruption (Lombok, Indonesia): the single greatest stratospheric gas release of the Common Era

    NASA Astrophysics Data System (ADS)

    Vidal, Céline M.; Métrich, Nicole; Komorowski, Jean-Christophe; Pratomo, Indyo; Michel, Agnès; Kartadinata, Nugraha; Robert, Vincent; Lavigne, Franck

    2016-10-01

    Large explosive eruptions inject volcanic gases and fine ash to stratospheric altitudes, contributing to global cooling at the Earth’s surface and occasionally to ozone depletion. The modelling of the climate response to these strong injections of volatiles commonly relies on ice-core records of volcanic sulphate aerosols. Here we use an independent geochemical approach which demonstrates that the great 1257 eruption of Samalas (Lombok, Indonesia) released enough sulphur and halogen gases into the stratosphere to produce the reported global cooling during the second half of the 13th century, as well as potential substantial ozone destruction. Major, trace and volatile element compositions of eruptive products recording the magmatic differentiation processes leading to the 1257 eruption indicate that Mt Samalas released 158 ± 12 Tg of sulphur dioxide, 227 ± 18 Tg of chlorine and a maximum of 1.3 ± 0.3 Tg of bromine. These emissions stand as the greatest volcanogenic gas injection of the Common Era. Our findings not only provide robust constraints for the modelling of the combined impact of sulphur and halogens on stratosphere chemistry of the largest eruption of the last millennium, but also develop a methodology to better quantify the degassing budgets of explosive eruptions of all magnitudes.

  20. The 1257 Samalas eruption (Lombok, Indonesia): the single greatest stratospheric gas release of the Common Era

    PubMed Central

    Vidal, Céline M.; Métrich, Nicole; Komorowski, Jean-Christophe; Pratomo, Indyo; Michel, Agnès; Kartadinata, Nugraha; Robert, Vincent; Lavigne, Franck

    2016-01-01

    Large explosive eruptions inject volcanic gases and fine ash to stratospheric altitudes, contributing to global cooling at the Earth’s surface and occasionally to ozone depletion. The modelling of the climate response to these strong injections of volatiles commonly relies on ice-core records of volcanic sulphate aerosols. Here we use an independent geochemical approach which demonstrates that the great 1257 eruption of Samalas (Lombok, Indonesia) released enough sulphur and halogen gases into the stratosphere to produce the reported global cooling during the second half of the 13th century, as well as potential substantial ozone destruction. Major, trace and volatile element compositions of eruptive products recording the magmatic differentiation processes leading to the 1257 eruption indicate that Mt Samalas released 158 ± 12 Tg of sulphur dioxide, 227 ± 18 Tg of chlorine and a maximum of 1.3 ± 0.3 Tg of bromine. These emissions stand as the greatest volcanogenic gas injection of the Common Era. Our findings not only provide robust constraints for the modelling of the combined impact of sulphur and halogens on stratosphere chemistry of the largest eruption of the last millennium, but also develop a methodology to better quantify the degassing budgets of explosive eruptions of all magnitudes. PMID:27721477

  1. Fast, sensitive hydrogen gas detection using single palladium nanowires that resist fracture.

    PubMed

    Yang, Fan; Taggart, David K; Penner, Reginald M

    2009-05-01

    Two types of pure palladium (Pd) nanowires, differentiated by microstructure, were electrodeposited: (1) nanocrystalline Pd nanowires (grain diameter approximately 5 nm, henceforth nc5-Pd) and (2) nanocrystalline Pd nanowires with a grain diameter of 15 nm (nc15-Pd). These nanowires were evaluated for the detection of hydrogen gas (H(2)). Despite their fundamental similarities, the behavior of these nanowires upon exposure to H(2) was dramatically and reproducibly different: nc5-Pd nanowires spontaneously fractured upon exposure to H(2) above 1-2%. Fractured nanowires continued to function as sensors for H(2) concentrations above 2%, actuated by the volume change associated with the alpha to beta phase transition of PdH(x). nc15-Pd nanowires, in contrast, withstood repeated exposures to H(2) up to 10% without fracturing. nc15-Pd nanowires showed a rapid (2 s at 10%) increase in resistance in the presence of H(2) and a response that scaled smoothly with [H(2)] spanning 5 orders of magnitude down to 2 ppm.

  2. Asymptotic safety goes on shell

    NASA Astrophysics Data System (ADS)

    Benedetti, Dario

    2012-01-01

    It is well known in quantum field theory that the off-shell effective action depends on the gauge choice and field parametrization used in calculating it. Nevertheless, the typical scheme in which the scenario of asymptotically safe gravity is investigated is an off-shell version of the functional renormalization group equation. Working with the Einstein-Hilbert truncation as a test bed, we develop a new scheme for the analysis of asymptotically safe gravity in which the on-shell part of the effective action is singled out and we show that the beta function for the essential coupling has no explicit gauge dependence. In order to reach our goal, we introduce several technical novelties, including a different decomposition of the metric fluctuations, a new implementation of the ghost sector and a new cut-off scheme. We find a nontrivial fixed point, with a value of the cosmological constant that is independent of the gauge-fixing parameters.

  3. Loading and compression of a single two-dimensional Bose gas in an optical accordion

    NASA Astrophysics Data System (ADS)

    Ville, J. L.; Bienaimé, T.; Saint-Jalm, R.; Corman, L.; Aidelsburger, M.; Chomaz, L.; Kleinlein, K.; Perconte, D.; Nascimbène, S.; Dalibard, J.; Beugnon, J.

    2017-01-01

    The experimental realization of two-dimensional (2D) Bose gases with a tunable interaction strength is an important challenge for the study of ultracold quantum matter. Here we report on the realization of an optical accordion creating a lattice potential with a spacing that can be dynamically tuned between 11 and 2 μ m . We show that we can load ultracold 87Rb atoms into a single node of this optical lattice in the large spacing configuration and then decrease nearly adiabatically the spacing to reach a strong harmonic confinement with frequencies larger than ωz/2 π =10 kHz. Atoms are trapped in an additional flat-bottom in-plane potential that is shaped with a high resolution. By combining these tools we create custom-shaped uniform 2D Bose gases with tunable confinement along the transverse direction and hence with a tunable interaction strength.

  4. Turbine vane gas film cooling with injection in the leading edge region from a single row of spanwise angled holes

    NASA Technical Reports Server (NTRS)

    Lecuyer, M. R.; Hanus, G. J.

    1976-01-01

    An experimental study of gas film cooling was conducted on a 3X size model turbine vane. Injection in the leading edge region was from a single row of holes angled in a spanwise direction. Measurements of the local heat flux downstream from the row of coolant holes, both with and without film coolant flow, were used to determine the film cooling performance presented in terms of the Stanton number ratio. Results for a range of coolant blowing ratio, M = 0 to 2.0, indicate a reduction in heat flux of up to 15 to 30 percent at a point 10 to 11 hole diameters downstream from injection. An optimum coolant blowing ratio corresponds to a coolant-to-freestream velocity ratio in the range of 0.5. The shallow injection angle resulted in superior cooling performance for injection closest to stagnation, while the effect of injection angle was insignificant for injection further from stagnation.

  5. Computation of decompression schedules for single inert gas-oxygen dives using a hand-held programmable calculator.

    PubMed

    Ranade, A; Peterson, R E

    1980-08-01

    An algorithm for on-site computation with a hand-held programmable calculator (TI-59, Texas Instruments) of single inert-gas decompression schedules is described. This program is based on Workman's 'M-value' method. It can compute decompression schedules with changes in the oxygen content of the breathing mixture and extension of stay at any decompression stop. The features of the program that enable calculation of atypical dive profiles, along with the portability of small calculators, would make such an algorithm suitable for on-site applications. However, since dive profiles generated by the program have not yet been tested, divers are warned not to generate schedules until their safety has been established by field tests.

  6. Preliminary recommendations on the design of the characterization program for the Hanford Site single-shell tanks: A system analysis. Volume 2, Closure-related analyte priorities, concentration thresholds, and detection limit goals based on public health concerns

    SciTech Connect

    Buck, J.W.; Peffers, M.S.; Hwang, S.T.

    1991-11-01

    The work described in this volume was conducted by Pacific Northwest Laboratory to provide preliminary recommendations on data quality objectives (DQOs) to support the Waste Characterization Plan (WCP) and closure decisions for the Hanford Site single-shell tanks (SSTs). The WCP describes the first of a two-phase characterization program that will obtain information to assess and implement disposal options for SSTs. This work was performed for the Westinghouse Hanford Company (WHC), the current operating contractor on the Hanford Site. The preliminary DQOs contained in this volume deal with the analysis of SST wastes in support of the WCP and final closure decisions. These DQOs include information on significant contributors and detection limit goals (DLGs) for SST analytes based on public health risk.

  7. Design of Accumulators and Liquid/Gas Charging of Single Phase Mechanically Pumped Fluid Loop Heat Rejection Systems

    NASA Technical Reports Server (NTRS)

    Bhandari, Pradeep; Dudik, Brenda; Birur, Gajanana; Karlmann, Paul; Bame, David; Mastropietro, A. J.

    2012-01-01

    For single phase mechanically pumped fluid loops used for thermal control of spacecraft, a gas charged accumulator is typically used to modulate pressures within the loop. This is needed to accommodate changes in the working fluid volume due to changes in the operating temperatures as the spacecraft encounters varying thermal environments during its mission. Overall, the three key requirements on the accumulator to maintain an appropriate pressure range throughout the mission are: accommodation of the volume change of the fluid due to temperature changes, avoidance of pump cavitation and prevention of boiling in the liquid. The sizing and design of such an accumulator requires very careful and accurate accounting of temperature distribution within each element of the working fluid for the entire range of conditions expected, accurate knowledge of volume of each fluid element, assessment of corresponding pressures needed to avoid boiling in the liquid, as well as the pressures needed to avoid cavitation in the pump. The appropriate liquid and accumulator strokes required to accommodate the liquid volume change, as well as the appropriate gas volumes, require proper sizing to ensure that the correct pressure range is maintained during the mission. Additionally, a very careful assessment of the process for charging both the gas side and the liquid side of the accumulator is required to properly position the bellows and pressurize the system to a level commensurate with requirements. To achieve the accurate sizing of the accumulator and the charging of the system, sophisticated EXCEL based spreadsheets were developed to rapidly come up with an accumulator design and the corresponding charging parameters. These spreadsheets have proven to be computationally fast and accurate tools for this purpose. This paper will describe the entire process of designing and charging the system, using a case study of the Mars Science Laboratory (MSL) fluid loops, which is en route to

  8. Impregnation of Catalytic Metals in Single-Walled Carbon Nanotubes for Toxic Gas Conversion in Life Support System

    NASA Technical Reports Server (NTRS)

    Li, Jing; Wignarajah, Kanapathipillai; Cinke, Marty; Partridge, Harry; Fisher, John

    2004-01-01

    Carbon nanotubes (CNTs) possess extraordinary properties such as high surface area, ordered chemical structure that allows functionalization, larger pore volume, and very narrow pore size distribution that have attracted considerable research attention from around the world since their discovery in 1991. The development and characterization of an original and innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size, increased adsorptive capacity due to their increased surface area and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. We present our recent investigation of using SWNTs as catalytic supporting materials to impregnate metals, such as rhodium (Rh), palladium (Pd) and other catalysts. A protocol has been developed to oxidize the SWNTs first and then impregnate the Rh in aqueous rhodium chloride solution, according to unique surface properties of SWNTs. The Rh has been successfully impregnated in SWNTs. The Rh-SWNTs have been characterized by various techniques, such as TGA, XPS, TEM, and FTIR. The project is funded by a NASA Research Announcement Grant to find applications of single walled nanocarbons in eliminating toxic gas Contaminant in life support system. This knowledge will be utilized in the development of a prototype SWNT KO, gas purification system that would represent a significant step in the development of high efficiency systems capable of selectively removing specific gaseous for use in regenerative life support system for human exploration missions.

  9. Modeling and validation of single-chamber microbial fuel cell cathode biofilm growth and response to oxidant gas composition

    SciTech Connect

    Ou, Shiqi; Zhao, Yi; Aaron, Douglas S.; Regan, John M.; Mench, Matthew M.

    2016-08-15

    This work describes experiments and computational simulations to analyze single-chamber, air-cathode microbial fuel cell (MFC) performance and cathodic limitations in terms of current generation, power output, mass transport, biomass competition, and biofilm growth. Steady-state and transient cathode models were developed and experimentally validated. Two cathode gas mixtures were used to explore oxygen transport in the cathode: the MFCs exposed to a helium-oxygen mixture (heliox) produced higher current and power output than the group of MFCs exposed to air or a nitrogen-oxygen mixture (nitrox), indicating a dependence on gas-phase transport in the cathode. Multi-substance transport, biological reactions, and electrochemical reactions in a multi-layer and multi-biomass cathode biofilm were also simulated in a transient model. The transient model described biofilm growth over 15 days while providing insight into mass transport and cathodic dissolved species concentration profiles during biofilm growth. Lastly, simulation results predict that the dissolved oxygen content and diffusion in the cathode are key parameters affecting the power output of the air-cathode MFC system, with greater oxygen content in the cathode resulting in increased power output and fully-matured biomass.

  10. Experimental and theoretical comparison of gas desorption energies on metallic and semiconducting single-walled carbon nanotubes.

    PubMed

    Mandeltort, Lynn; Chen, De-Li; Saidi, Wissam A; Johnson, J Karl; Cole, Milton W; Yates, John T

    2013-05-22

    Single-walled carbon nanotubes (SWNTs) exhibit high surface areas and precisely defined pores, making them potentially useful materials for gas adsorption and purification. A thorough understanding of the interactions between adsorbates and SWNTs is therefore critical to predicting adsorption isotherms and selectivities. Metallic (M-) and semiconducting (S-) SWNTs have extremely different polarizabilities that might be expected to significantly affect the adsorption energies of molecules. We experimentally and theoretically show that this expectation is contradicted, for both a long chain molecule (n-heptane) and atoms (Ar, Kr, and Xe). Temperature-programmed desorption experiments are combined with van der Waals corrected density functional theory, examining adsorption on interior and exterior sites of the SWNTs. Our calculations show a clear dependence of the adsorption energy on nanotube diameter but not on whether the tubes are conducting or insulating. We find no significant experimental or theoretical difference in adsorption energies for molecules adsorbed on M- and S-SWNTs having the same diameter. Hence, we conclude that the differences in polarizabilities between M- and S-SWNTs have a negligible influence on gas adsorption for spherical molecules as well as for highly anisotropic molecules such as n-heptane. We expect this conclusion to apply to all types of adsorbed molecules where van der Waals interactions govern the molecular interaction with the SWNT.

  11. Applied reaction dynamics: Efficient synthesis gas production via single collision partial oxidation of methane to CO on Rh(111)

    NASA Astrophysics Data System (ADS)

    Gibson, K. D.; Viste, M.; Sibener, S. J.

    2006-10-01

    Supersonic molecular beams have been used to determine the yield of CO from the partial oxidation of CH4 on a Rh(111) catalytic substrate, CH4+(1/2)O2→CO +2H2, as a function of beam kinetic energy. These experiments were done under ultrahigh vacuum conditions with concurrent molecular beams of O2 and CH4, ensuring that there was only a single collision for the CH4 to react with the surface. The fraction of CH4 converted is strongly dependent on the normal component of the incident beam's translational energy, and approaches unity for energies greater than ˜1.3eV. Comparison with a simplified model of the methane-Rh(111) reactive potential gives insight into the barrier for methane dissociation. These results demonstrate the efficient conversion of methane to synthesis gas, CO +2H2, are of interest in hydrogen generation, and have the optimal stoichiometry for subsequent utilization in synthetic fuel production (Fischer-Tropsch or methanol synthesis). Moreover, under the reaction conditions explored, no CO2 was detected, i.e., the reaction proceeded with the production of very little, if any, unwanted greenhouse gas by-products. These findings demonstrate the efficacy of overcoming the limitations of purely thermal reaction mechanisms by coupling nonthermal mechanistic steps, leading to efficient C-H bond activation with subsequent thermal heterogeneous reactions.

  12. Modeling and validation of single-chamber microbial fuel cell cathode biofilm growth and response to oxidant gas composition

    DOE PAGES

    Ou, Shiqi; Zhao, Yi; Aaron, Douglas S.; ...

    2016-08-15

    This work describes experiments and computational simulations to analyze single-chamber, air-cathode microbial fuel cell (MFC) performance and cathodic limitations in terms of current generation, power output, mass transport, biomass competition, and biofilm growth. Steady-state and transient cathode models were developed and experimentally validated. Two cathode gas mixtures were used to explore oxygen transport in the cathode: the MFCs exposed to a helium-oxygen mixture (heliox) produced higher current and power output than the group of MFCs exposed to air or a nitrogen-oxygen mixture (nitrox), indicating a dependence on gas-phase transport in the cathode. Multi-substance transport, biological reactions, and electrochemical reactions inmore » a multi-layer and multi-biomass cathode biofilm were also simulated in a transient model. The transient model described biofilm growth over 15 days while providing insight into mass transport and cathodic dissolved species concentration profiles during biofilm growth. Lastly, simulation results predict that the dissolved oxygen content and diffusion in the cathode are key parameters affecting the power output of the air-cathode MFC system, with greater oxygen content in the cathode resulting in increased power output and fully-matured biomass.« less

  13. Modeling and validation of single-chamber microbial fuel cell cathode biofilm growth and response to oxidant gas composition

    NASA Astrophysics Data System (ADS)

    Ou, Shiqi; Zhao, Yi; Aaron, Douglas S.; Regan, John M.; Mench, Matthew M.

    2016-10-01

    This work describes experiments and computational simulations to analyze single-chamber, air-cathode microbial fuel cell (MFC) performance and cathodic limitations in terms of current generation, power output, mass transport, biomass competition, and biofilm growth. Steady-state and transient cathode models were developed and experimentally validated. Two cathode gas mixtures were used to explore oxygen transport in the cathode: the MFCs exposed to a helium-oxygen mixture (heliox) produced higher current and power output than the group of MFCs exposed to air or a nitrogen-oxygen mixture (nitrox), indicating a dependence on gas-phase transport in the cathode. Multi-substance transport, biological reactions, and electrochemical reactions in a multi-layer and multi-biomass cathode biofilm were also simulated in a transient model. The transient model described biofilm growth over 15 days while providing insight into mass transport and cathodic dissolved species concentration profiles during biofilm growth. Simulation results predict that the dissolved oxygen content and diffusion in the cathode are key parameters affecting the power output of the air-cathode MFC system, with greater oxygen content in the cathode resulting in increased power output and fully-matured biomass.

  14. AN INVESTIGATION INTO THE MECHANICS OF SINGLE CRYSTAL TURBINE BLADES WITH A VIEW TOWARDS ENHANCING GAS TURBINE EFFICIENCY

    SciTech Connect

    K.R. Rajagopal; I.J. Rao

    2006-05-05

    The demand for increased efficiency of gas turbines used in power generation and aircraft applications has fueled research into advanced materials for gas turbine blades that can withstand higher temperatures in that they have excellent resistance to creep. The term ''Superalloys'' describes a group of alloys developed for applications that require high performance at elevated temperatures. Superalloys have a load bearing capacity up to 0.9 times their melting temperature. The objective of the investigation was to develop a thermodynamic model that can be used to describe the response of single crystal superalloys that takes into account the microstructure of the alloy within the context of a continuum model. Having developed the model, its efficacy was to be tested by corroborating the predictions of the model with available experimental data. Such a model was developed and it is implemented in the finite element software ABAQUS/STANDARD through a user subroutine (UMAT) so that the model can be used in realistic geometries that correspond to turbine blades.

  15. Single-walled carbon nanotubes as stationary phase in gas chromatographic separation and determination of argon, carbon dioxide and hydrogen.

    PubMed

    Safavi, Afsaneh; Maleki, Norooz; Doroodmand, Mohammad Mahdi

    2010-08-24

    A chromatographic technique is introduced based on single-walled carbon nanotubes (SWCNTs) as stationary phase for separation of Ar, CO(2) and H(2) at parts per million (ppm) levels. The efficiency of SWCNTs was compared with solid materials such as molecular sieve, charcoal, multi-walled carbon nanotubes and carbon nanofibers. The morphology of SWCNTs was optimized for maximum adsorption of H(2), CO(2) and Ar and minimum adsorption of gases such as N(2), O(2), CO and H(2)O vapour. To control temperature of the gas chromatography column, peltier cooler was used. Mixtures of Ar, CO(2) and H(2) were separated according to column temperature program. Relative standard deviation for nine replicate analyses of 0.2 mL H(2) containing 10 microL of each Ar or CO(2) was 2.5% for Ar, 2.8% for CO(2) and 3.6% for H(2). The interfering effects of CO, and O(2) were investigated. Working ranges were evaluated as 40-600 ppm for Ar, 30-850 ppm for CO(2) and 10-1200 ppm for H(2). Significant sensitivity, small relative standard deviation (RSD) and acceptable limit of detection (LOD) were obtained for each analyte, showing capability of SWCNTs for gas separation and determination processes. Finally, the method was used to evaluate the contents of CO(2) in air sample.

  16. Detachment of CVD-grown graphene from single crystalline Ni films by a pure gas phase reaction

    NASA Astrophysics Data System (ADS)

    Zeller, Patrick; Henß, Ann-Kathrin; Weinl, Michael; Diehl, Leo; Keefer, Daniel; Lippmann, Judith; Schulz, Anne; Kraus, Jürgen; Schreck, Matthias; Wintterlin, Joost

    2016-11-01

    Despite great previous efforts there is still a high need for a simple, clean, and upscalable method for detaching epitaxial graphene from the metal support on which it was grown. We present a method based on a pure gas phase reaction that is free of solvents and polymer supports and avoids mechanical transfer steps. The graphene was grown on 150 nm thick, single crystalline Ni(111) films on Si(111) wafers with YSZ buffer layers. Its quality was monitored by using low energy electron diffraction and scanning tunneling microscopy. The gas phase etching uses a chemical transport reaction, the so-called Mond process, based on the formation of gaseous nickel tetracarbonyl in ~ 1 bar of CO at ~ 75 °C and by adding small amounts of sulfide catalysts. X-ray photoelectron spectroscopy, Raman spectroscopy and scanning electron microscopy were used to characterize the detached graphene. It was found that the method successfully removes the nickel from underneath the graphene layer, so that the graphene lies on the insulating oxide buffer layer. Small residual particles of nickel sulfide and cracks in the obtained graphene layer were identified. The defect concentrations were comparable to graphene samples obtained by wet chemical etching and by the bubbling transfer.

  17. Environmental Stress Testing of the Single Sample Cylinder: A Proven Consensus Standard for Internal Gas Analysis (IGA) or Residual Gas Analysis (RGA)

    NASA Technical Reports Server (NTRS)

    Schuessler, Philipp WH

    2010-01-01

    In August 2008, Schuessler Consulting was contracted by NASA GSFC in support of the NASA Electronic Parts and Packaging (NEPP) program to perform two separate studies on moisture laden air in a stainless steel cylinder that had been designed to become a consensus standard for Test Method 1018. This Test Method was originally released for hybrids under Mil. Std. 883 but was quickly utilized on other microelectronic devices under the auspice of Mil. Std. 750. The cylinder had subsequently been fabricated for the 750 community. It was back-filled with moist air and subsequently analyzed over a period of time under a previous NASA contract. It had been shown that moisture in the 4000 - 5000 ppm range could be analyzed rather precisely with a mass spectrometer, commonly referred to as a Residual Gas Analyzer (RGA). The scope of this study was to ascertain if the composition and precision varied as a function of thermal shock at sub-zero temperatures and whether there was consensus when the standard was submitted to other RGA units. It was demonstrated and published that the consensus standard would yield precise RGA data for moisture within +/- 1% when optimized for a given RGA unit. It has been subsequently shown in this study at Oneida Research Services, that sub-zero storage did not affect that precision when a well-defined protocol for the analysis was followed. The consensus standard was taken to a second facility for analysis where it was found that moisture adsorption on the transfer lines caused precision to drop to +/- 12%. The Single Sample Cylinder (SSC) is a one liter stainless steel cylinder with associated sampling valves and has considerable weight and volume. But this considerable size allows for approximately 300 gas samples of the same composition to be delivered to any RGA unit. Lastly, a smaller cylinder, approximately 75 cc, of a second consensus standard was fabricated and tested with a different mix of fixed gases where moisture was kept in the

  18. Increasing optical density of single-layer multi-polymer bulk-heterojunction OPVs using CdSe(ZnS) core(shell) quantum dots

    NASA Astrophysics Data System (ADS)

    Bump, Buddy J.; Olson, Grant T.; Savage, Richard; Echols, Robert S.

    2014-10-01

    Photovoltaic technology has powerful implications from commercial and national security standpoints. Due to the high material cost of silicon solar devices, inexpensive and lightweight polymer based solar is desirable to meet the demand for decentralized electrical power production in traditionally "off-grid" areas. Using a blend of Poly(3-hexylthiophene- 2,5-diyl) (P3HT), Phenyl-C61-butyric acid methyl ester (PCBM), and the low band-gap polymer Poly[2,6-(4,4-bis-(2- ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT), we have fabricated devices with a wide spectral response and 3% power conversion efficiency in AM 1.5 conditions. Due to low absorptivity in the peak of the solar spectra (500nm), we have blended this previous polymer system with CdSe(ZnS) core (shell) quantum dots to improve absorption, and thus power conversion efficiencies. Devices were prepared with quantum dots having a peak absorbance at 560nm and an emission wavelength of 577nm, with device loading ranging from 0% to 2.7% by weight. The relationship between quantum dot concentration and device performance is discussed, along with the impact of quantum dot concentration on thermal resistance to morphology changes.

  19. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ecton, P. A.; Beatty, J.; Verbeck, G.; Lakshantha, W.; Rout, B.; Perez, J. M.

    2016-11-01

    We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  20. Ultracold Chemical Reactions of a Single Rydberg Atom in a Dense Gas

    NASA Astrophysics Data System (ADS)

    Schlagmüller, Michael; Liebisch, Tara Cubel; Engel, Felix; Kleinbach, Kathrin S.; Böttcher, Fabian; Hermann, Udo; Westphal, Karl M.; Gaj, Anita; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman; Pérez-Ríos, Jesús; Greene, Chris H.

    2016-07-01

    Within a dense environment (ρ ≈1014 atoms /cm3 ) at ultracold temperatures (T <1 μ K ), a single atom excited to a Rydberg state acts as a reaction center for surrounding neutral atoms. At these temperatures, almost all neutral atoms within the Rydberg orbit are bound to the Rydberg core and interact with the Rydberg atom. We have studied the reaction rate and products for n S 87Rb Rydberg states, and we mainly observe a state change of the Rydberg electron to a high orbital angular momentum l , with the released energy being converted into kinetic energy of the Rydberg atom. Unexpectedly, the measurements show a threshold behavior at n ≈100 for the inelastic collision time leading to increased lifetimes of the Rydberg state independent of the densities investigated. Even at very high densities (ρ ≈4.8 ×1014 cm-3 ), the lifetime of a Rydberg atom exceeds 10 μ s at n >140 compared to 1 μ s at n =90 . In addition, a second observed reaction mechanism, namely, Rb2+ molecule formation, was studied. Both reaction products are equally probable for n =40 , but the fraction of Rb2+ created drops to below 10% for n ≥90 .