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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. 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.

  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. 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

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

    SciTech Connect

    Lockrem, L.L.

    1997-08-08

    The Vapor Issue Resolution Program tasked the Vapor Team (the team) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-T-104. This document presents sampling data resulting from the February 7, 1996 sampling of SST 241-T-104. Analytical results will be presented in separate reports issued by the laboratories that supplied and analyzed the sampling media.

  7. Flammable Gas Release Estimates for Modified Sluicing Retrieval of Waste from Selected Hanford Single-Shell Tanks

    SciTech Connect

    Huckaby, James L.; Wells, Beric E.

    2004-03-05

    The high-level radioactive wastes in many single-shell tanks (SSTs) at the Hanford Site are to be retrieved by a modified sluicing method that uses water jets to dissolve the water-soluble waste and mobilize the water-insoluble waste. Retrieval operations will liberate any waste gases trapped in the wetted solid waste matrix, and these gases will be released into the tank headspaces. Because the trapped gases include the flammable species hydrogen, methane, and ammonia, a concern exists that a flammable mixture could be formed in the tank headspaces. This report combines conservative retained gas inventory estimates and tank data with anticipated waste retrieval rates to estimate the potential headspace flammability of selected SSTs during modified sluicing waste retrieval operations. Considered here are nine of the 12 tanks from the 241-S tank farm (241-S-107, 241-S-111, and 241-S 112 are not considered) and Tank 241-U-107. This report is intended to support the specification of process controls that ensure flammable conditions do not develop in the tank headspaces. Consequently, the physical scenarios considered, the models developed to estimate retained gas releases and the tank headspace compositions under these scenarios, and the model input data are intended to conservatively assess the potential to reach headspace flammability. The analyses are intended to address worst-case conditions and establish reasonable upper bounds on the achievable flammability of the tank headspaces. Flammable retained gas inventories, for example, are based on the 95th percentile developed by Barker and Hedengren (2003), giving 95% confidence that actual inventories are smaller than those used in the calculations. Gas releases and headspace flammability were evaluated for three general scenarios: a very aggressive dissolution and erosion of saltcake waste by water jets impinging on the waste surface, the drainage of interstitial liquids from saltcake during a shutdown of the

  8. Vapor and gas sampling of single-shell tank 241-BX-105 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-BX-105. This document presents sampling data resulting from the April 24, 1996 sampling of SST 241-BX-105. Analytical results will be presented in a separate report issued by Pacific Northwest National Laboratory (PNNL), which supplied and analyzed the sampling media.

  9. Vapor and gas sampling of single-shell tank 241-BX-110 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-BX-110. This document presents sampling data resulting from the April 30, 1996 sampling of SST 241-BX-110. Analytical results will be presented in a separate report issued by Pacific Northwest National Laboratory (PNNL), which supplied and analyzed the sampling media.

  10. Vapor and gas sampling of single-shell tank 241-C-107 using the 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-C-107. This document presents sampling data resulting from the March 26, 1996 sampling of SST 241-C-107. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory which supplied and analyzed the sample media. The team collected representative headspace samples using the In Situ Vapor Sampling System (ISVS).

  11. Vapor and gas sampling of single-shell tank 241-BX-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 (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-BX-102. This document presents In Situ vapor Sampling System (ISVS) data resulting from the July 31, 1996 sampling of SST 241-BX-102. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which supplied and analyzed the sample media.

  12. Vapor and gas sampling of single-shell tank 241-B-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-B-102. This document presents sampling data resulting from the April 18, 1996 sampling of SST 241-B-102. Analytical results will be presented in a separate report issued by Pacific Northwest National Laboratory (PNNL), which supplied and analyzed the sampling media. The team, consisting of Sampling and Mobile Laboratories (SML) and Special Analytical Studies (SAS) personnel, used the vapor sampling system (VSS) to collect representative samples of the air, gases, and vapors from the headspace of SST 241-B-102 with sorbent traps and SUMMA canisters.

  13. Vapor and gas sampling of single-shell tank 241-C-107 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-C-107. This document presents sampling data resulting from the February 7, 1997 sampling of SST 241-C-107. 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 sampling events on SST 241-C-107. 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.

  14. 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.

  15. Vapor and gas sampling of single-shell tank 241-TY-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-TY-102. This document presents sampling data resulting from the April 12, 1996 sampling of SST 241-TY-102. Analytical results will be presented in separate reports issued by the laboratories that supplied and analyzed the sampling media. The team, consisting of Sampling and Mobile Laboratories (SML) and Special Analytical Studies (SAS) personnel, used the vapor sampling system (VSS) to collect representative samples of the air, gases, and vapors from the headspace of SST 241-TY-102 with sorbent traps and SUMMA canisters.

  16. 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.

  17. 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.

  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. 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.

  20. 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.

  1. 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.

  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. HANFORD SINGLE SHELL TANK (SST) WASTE RETRIEVAL PROCESS

    SciTech Connect

    SAMS, T.L.

    2005-03-02

    This document discusses the decision-making process used by the DOE Office of River Protection to determine completion of waste retrieval for individual single shell tanks (SSTs) at the Hanford Site with respect to allowable waste residuals.

  4. 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.

  5. Single-shell tank ventilation upgrades needs analysis report

    SciTech Connect

    Kriskovich, J.R., Fluor Daniel Hanford

    1997-02-03

    This report was written to comply with the objectives of the Hanford Federal Facility Agreement and Consent Order, Tri-Party Agreement Milestone M-43-03 Provide to the Washington State Department of Ecology and Department of Health the Results of the Single-Shell Tank Ventilation Upgrades Needs Analysis. The needs analysis consists of identifying the current type and status of each single-shell tank ventilation system, identifying current and projected authorization basis requirements, and identifying ventilation system compliance deficiencies.

  6. 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.

  7. Enhanced ethanol gas sensing properties of SnO₂-core/ZnO-shell nanostructures.

    PubMed

    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.

  8. Kinematic arguments against single relativistic shell models for GRBs

    SciTech Connect

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

    1997-09-01

    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{sup {minus}3}, implying that single relativistic shells require 10{sup 3} times more energy than previously thought. They conclude that either the central site of a GRB must produce {approx}10{sup 51} erg/s{sup {minus}1} for hundreds of seconds, or the relativistic shell must have structure on a scales the order of {radical}{epsilon}{Gamma}{sup {minus}1}, where {Gamma} is the bulk Lorentz factor ({approximately}10{sup 2} to 10{sup 3}) and {epsilon} is the efficiency.

  9. 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.

  10. 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

  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. 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.

  13. 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.

  14. Single Shell Tank (SST) Retrieval Sequence FY 2000 Update

    SciTech Connect

    GARFIELD, J.S.

    2000-09-27

    This document describes the baseline single-shell tank (SST) waste retrieval sequence for the River Protection Project (RPP) updated for Fiscal Year 2000. The SST retrieval sequence identifies the proposed retrieval order (sequence), the tank selection and prioritization rationale, and planned retrieval dates for Hanford SSTs. In addition, the tank selection criteria and reference retrieval method for this sequence are discussed.

  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. Supersonic gas shell for puff pinch experiments

    NASA Astrophysics Data System (ADS)

    Smith, R. S., III; Doggett, W. O.; Roth, I.; Stallings, C.

    1982-09-01

    An easy-to-fabricate, conical, annular supersonic nozzle has been developed for use in high-power, puff gas z-pinch experiments. A fast responding conical pressure probe has also been developed as an accurate supersonic gas flow diagnostic for evaluating the transient gas jet formed by the nozzle. Density profile measurements show that the magnitude and radial position of the gas annulus are fairly constant with distance from the nozzle, but the gas density in the center of the annulus increases with distance from the nozzle.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. Shells, holes, worms, high-velocity gas and the z-distribution of gas in galaxies.

    NASA Astrophysics Data System (ADS)

    Rand, R. J.

    The author gives an overview of the current observational understanding of vertically extended gas components in spiral galaxies and the various phenomena which come under such names as shells, holes, worms, and high-velocity gas. For the most part, the focus is on recent high-resolution interferometric studies. The author concentrates on cold gas, and briefly on warm ionized gas, in the Milky Way and a few nearby spirals. Along the way, it is seen how phenomena such as worms and shells may be related to the formation and maintenance of the vertically extended components.

  3. 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].

  4. Structural qualification of the multifunctional instrument tree for installation in double-shell and 100-series single-shell tanks

    SciTech Connect

    Strohlow, J.P.

    1995-12-01

    This document provides the technical basis and methodology for qualifying the multifunctional instrument tree (MIT) structure for installation in double-shell and 100-series single-shell tanks. Structural qualification for MIT installations in specific tanks are also contained in this document.

  5. Architecture in outer space. [multilayer shell systems filled with gas

    NASA Technical Reports Server (NTRS)

    Pokrovskiy, G. I.

    1974-01-01

    Mulilayer thin film structures consisting of systems of shells filled with gas at some pressure are recommended for outer space structures: Large mirrors to collect light and radio waves, protection against meteoric impact and damage, and for connectors between state space stations in the form of orbital rings. It is projected that individual orbital rings will multiply and completely seal a star trapping its high temperature radiation and transforming it into low temperature infrared and short wave radio emission; this radiation energy could be utilized for technological and biological processes.

  6. 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

  7. 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.

  8. 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.

  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. 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.

  11. The detached dust and gas shells around the carbon star U Antliae

    NASA Astrophysics Data System (ADS)

    Maercker, M.; Olofsson, H.; Eriksson, K.; Gustafsson, B.; Schöier, F. L.

    2010-02-01

    Context. Geometrically thin, detached shells of gas have been found around a handful of carbon stars. The current knowledge on these shells is mostly based on CO radio line data. However, imaging in scattered stellar light adds important new information as well as allows studies of the dust shells. Aims: Previous observations of scattered stellar light in the circumstellar medium around the carbon star U Ant were taken through filters centred on the resonance lines of K and Na. These observations could not separate the scattering by dust and atoms. The aim of this paper is to remedy this situation. Methods: We have obtained polarization data on stellar light scattered in the circumstellar medium around U Ant through filters which contain no strong lines, making it possible to differentiate between the two scattering agents. Kinematic, as well as spatial, information on the gas shells were obtained through high-resolution echelle spectrograph observations of the KI and NaD lines. Results: We confirm the existence of two detached shells around U Ant. The inner shell (at a radius of ≈43´´ and a width of ≈2´´) consists mainly of gas, while the outer shell (at a radius of ≈50´´ and a width of ≈7´´) appears to consist exclusively of dust. Both shells appear to have an over-all spherical geometry. The gas shell mass is estimated to be 2 × 10-3~M⊙, while the mass of the dust shell is estimated to be 5 × 10-5~M⊙. The derived expansion velocity, from the KI and NaD lines, of the gas shell, 19.5 km s-1, agrees with that obtained from CO radio line data. The inferred shell age is 2700 years. There is structure, e.g. in the form of arcs, inside the gas shell, but it is not clear whether these are due to additional shells. Conclusions: Our results support the hypothesis that the observed geometrically thin, detached shells around carbon stars are the results of brief periods of intense mass loss, probably associated with thermal pulses, and subsequent wind

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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. PMID:27350177

  18. Magnetically controlled multifrequency invisibility cloak with a single shell of ferrite material

    NASA Astrophysics Data System (ADS)

    Wang, Xiaohua; Liu, Youwen

    2015-02-01

    A magnetically controlled multifrequency invisibility cloak with a single shell of the isotropic and homogeneous ferrite material has been investigated based on the scattering cancellation method from the Mie scattering theory. The analytical and simulated results have demonstrated that such this shell can drastically reduce the total scattering cross-section of this cloaking system at multiple frequencies. These multiple cloaking frequencies of this shell can be externally controlled since the magnetic permeability of ferrites is well tuned by the applied magnetic field. This may provide a potential way to design a tunable multifrequency invisibility cloak with considerable flexibility.

  19. 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).

  20. 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.

  1. 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...

  2. 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. PMID:16608315

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Single-crystal apatite nanowires sheathed in graphitic shells: synthesis, characterization, and application.

    PubMed

    Jeong, Namjo; Cha, Misun; Park, Yun Chang; Lee, Kyung Mee; Lee, Jae Hyup; Park, Byong Chon; Lee, Junghoon

    2013-07-23

    Vertically aligned one-dimensional hybrid structures, which are composed of apatite and graphitic structures, can be beneficial for orthopedic applications. However, they are difficult to generate using the current method. Here, we report the first synthesis of a single-crystal apatite nanowire encapsulated in graphitic shells by a one-step chemical vapor deposition. Incipient nucleation of apatite and its subsequent transformation to an oriented crystal are directed by derived gaseous phosphorine. Longitudinal growth of the oriented apatite crystal is achieved by a vapor-solid growth mechanism, whereas lateral growth is suppressed by the graphitic layers formed through arrangement of the derived aromatic hydrocarbon molecules. We show that this unusual combination of the apatite crystal and the graphitic shells can lead to an excellent osteogenic differentiation and bony fusion through a programmed smart behavior. For instance, the graphitic shells are degraded after the initial cell growth promoted by the graphitic nanostructures, and the cells continue proliferation on the bare apatite nanowires. Furthermore, a bending experiment indicates that such core-shell nanowires exhibited a superior bending stiffness compared to single-crystal apatite nanowires without graphitic shells. The results suggest a new strategy and direction for bone grafting materials with a highly controllable morphology and material conditions that can best stimulate bone cell differentiation and growth. PMID:23755838

  15. Core-shell nanostructures from single poly(N-vinylcaprolactam) macromolecules: stabilization and visualization.

    PubMed

    Bronstein, Lyudmila M; Kostylev, Maxim; Tsvetkova, Irina; Tomaszewski, John; Stein, Barry; Makhaeva, Elena E; Okhapkin, Ivan; Khokhlov, Alexei R

    2005-03-29

    Formation of core-shell poly(N-vinylcaprolactam) (PVCL) single-molecule nanostructures due to interaction of PVCL with metal ions was studied using transmission electron microscopy, 13C NMR, and light scattering. This study demonstrates that addition of CoCl2 to PVCL in its globular conformation yields unimolecular core-shell polymer particles with the core decorated with Co(II) ions. The crucial condition for formation of well-defined unimolecular nanostructures is the presence of stable globular aggregates in aqueous solution. Moreover, the metal ions should have a sufficiently high coordination number (higher than 2) to provide a cross-linking and stabilization of the core.

  16. 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.

  17. The effect of mix on capsule yields as a function of shell thickness and gas fill

    SciTech Connect

    Bradley, P. A.

    2014-06-15

    An investigation of direct drive capsules with different shell thicknesses and gas fills was conducted to examine the amount of shock induced (Richtmyer-Meshkov) mix versus Rayleigh-Taylor mix from deceleration of the implosion. The RAGE (Eulerian) code with a turbulent mix model was used to model these capsules for neutron yields along with time-dependent mix amounts. The amount of Richtmyer-Meshkov induced mix from the shock breaking out of the shell is about 0.1 μg (0.15 μm of shell material), while the Rayleigh-Taylor mix is of order 1 μg and determines the mixed simulation yield. The simulations were able to calculate a yield over mix (YOM) ratio (experiment/mix simulation) between 0.5 and 1.0 for capsules with shell thicknesses ranging from 7.5 to 20 μm and with gas fills between 3.8 and 20 atm of D{sub 2} or DT. The simulated burn averaged T{sub ion} values typically lie with 0.5 keV of the data, which is within the measurement error. For capsules with shell thicknesses >25 μm, the YOM values drop to 0.10 ± 0.05, suggesting that some unmodeled effect needs to be accounted for in the thickest capsules.

  18. Acoustic modes of finite length homogeneous and layered cylindrical shells: Single and multiwall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Li, Guangyan; Lamberton, G. A.; Gladden, J. R.

    2008-08-01

    We present a numerical study of the normal modes of vibration of both homogeneous and heterogeneous finite length cylindrical shells of arbitrary wall thickness with applications toward single and multiwall carbon nanotubes in the continuum limit. The method is checked by comparison of computed and measured resonance spectra for a machined aluminum cylindrical shell. The dependence of the natural frequencies of various radial modes with the length and radius of single wall tubes is investigated and compared to atomistic models and Raman spectroscopy data. The radial dependence for the radial breathing mode and four harmonics of the squash mode are found to be well fitted by power laws and agree with analytical solutions in the thin wall limit. A general model for an elastically heterogeneous layered cylindrical shell is applied to multiwall tubes with graphene sheets and gaps between the sheets represented by two different materials. The frequency dependence on length and diameter is investigated for tubes composed of two to four concentric shells.

  19. Improved fidelity of brain microstructure mapping from single-shell diffusion MRI.

    PubMed

    Taquet, Maxime; Scherrer, Benoit; Boumal, Nicolas; Peters, Jurriaan M; Macq, Benoit; Warfield, Simon K

    2015-12-01

    Diffusion weighted imaging (DWI) is sensitive to alterations in the diffusion of water molecules caused by microstructural barriers. Different microstructural compartments are characterized by differences in DWI signal. Diffusion tensor imaging conflates the signal from these compartments into a single tensor, which poorly represents multiple white matter fascicles and extra-axonal space. Diffusion compartment imaging (DCI) models overcome this limitation by providing parametric representations for the signal contribution of each compartment, thereby improving the fidelity of brain microstructure mapping. However, current approaches fail to identify DCI model parameters from conventional single-shell DWI with the desired accuracy. It has been demonstrated that part of this inaccuracy is due to the ill-posedness of the estimation of DCI model parameters from conventional single-shell acquisitions. In this paper, we propose to regularize the estimation problem for single-shell DWI by learning a prior distribution of DCI model parameters from DWI acquired at multiple b-values in an external population of subjects. We demonstrate that this population-informed prior enables, for the first time, accurate estimation of DCI models from single-shell DWI typically acquired in clinical practice. We validated our approach on synthetic and in vivo data of healthy subjects and patients with autism spectrum disorder. We applied the approach to population studies of brain microstructure in autism and found that introducing a population-informed prior leads to reliable detection of group differences. Our algorithm enables novel investigation from large existing DWI datasets in normal development and in disease and injury. PMID:26529580

  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. Ethanol Gas Detection Using a Yolk-Shell (Core-Shell) α-Fe2O3 Nanospheres as Sensing Material.

    PubMed

    Wang, LiLi; Lou, Zheng; Deng, Jianan; Zhang, Rui; Zhang, Tong

    2015-06-17

    Three-dimensional (3D) nanostructures of α-Fe2O3 materials, including both hollow sphere-shaped and yolk-shell (core-shell)-shaped, have been successfully synthesized via an environmentally friendly hydrothermal approach. By expertly adjusting the reaction time, the solid, hollow, and yolk-shell shaped α-Fe2O3 can be selectively synthesized. Yolk-shell α-Fe2O3 nanospheres display outer diameters of 350 nm, and the interstitial hollow spaces layer is intimately sandwiched between the inner and outer shell of α-Fe2O3 nanostructures. The possible growth mechanism of the yolk-shell nanostructure is proposed. The results showed that the well-defined bilayer interface effectively enhanced the sensing performance of the α-Fe2O3 nanostructures (i.e., yolk-shell α-Fe2O3@α-Fe2O3), owing predominantly to the unique nanostructure, thus facilitated the transport rate and augmented the adsorption quantity of the target gas molecule under gas detection.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Smart single-chip gas sensor microsystem.

    PubMed

    Hagleitner, C; Hierlemann, A; Lange, D; Kummer, A; Kerness, N; Brand, O; Baltes, H

    2001-11-15

    Research activity in chemical gas sensing is currently directed towards the search for highly selective (bio)chemical layer materials, and to the design of arrays consisting of different partially selective sensors that permit subsequent pattern recognition and multi-component analysis. Simultaneous use of various transduction platforms has been demonstrated, and the rapid development of integrated-circuit technology has facilitated the fabrication of planar chemical sensors and sensors based on three-dimensional microelectromechanical systems. Complementary metal-oxide silicon processes have previously been used to develop gas sensors based on metal oxides and acoustic-wave-based sensor devices. Here we combine several of these developments to fabricate a smart single-chip chemical microsensor system that incorporates three different transducers (mass-sensitive, capacitive and calorimetric), all of which rely on sensitive polymeric layers to detect airborne volatile organic compounds. Full integration of the microelectronic and micromechanical components on one chip permits control and monitoring of the sensor functions, and enables on-chip signal amplification and conditioning that notably improves the overall sensor performance. The circuitry also includes analog-to-digital converters, and an on-chip interface to transmit the data to off-chip recording units. We expect that our approach will provide a basis for the further development and optimization of gas microsystems.

  7. Reissner-Nordström thin-shell wormholes with generalized cosmic Chaplygin gas

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Azam, M.

    2013-09-01

    Following Visser’s approach (Visser in Phys. Rev. D 39:3182, 1989; Nucl. Phys. B 328:203, 1989; Lorentzian wormholes. AIP Press, New York, 1996) of cut and paste, we construct Reissner-Nordström thin-shell wormholes by taking the generalized cosmic Chaplygin gas for the exotic matter located at the wormhole throat. The Darmois-Israel conditions are used to determine the dynamical quantities of the system. The viability of the thin-shell wormholes is explored with respect to radial perturbations preserving the spherical symmetry. We find stable as well as unstable Reissner-Nordström thin-shell wormhole solutions depending upon the model parameters. Finally, we compare our results with both generalized and modified Chaplygin gases.

  8. 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.

  9. 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

  10. INFRARED AND X-RAY SPECTROSCOPY OF THE Kes 75 SUPERNOVA REMNANT SHELL: CHARACTERIZING THE DUST AND GAS PROPERTIES

    SciTech Connect

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

    2012-01-20

    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 keV. 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 {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 Multiplication-Sign 10{sup -2} M{sub Sun }, 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

  11. 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

  12. 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

  13. One-pot synthesis of yolk-shell materials with single, binary, ternary, quaternary, and quinary systems.

    PubMed

    Hong, Young Jun; Son, Mun Yeong; Park, Byung Kyu; Kang, Yun Chan

    2013-07-01

    A facile, one-pot method of systematically synthesizing yolk-shell materials with complex compositions is proposed. The spray pyrolysis process for obtaining yolk-shell materials is advantageous because it is highly efficient, allows high throughput, comprises a single-step reaction, and is a continuous process that yields homogeneous composition and enables facile control of the mean size.

  14. 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).

  15. Real-time detection of chlorine gas using Ni/Si shell/core nanowires

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Jin; Heo, Kwang; Lee, Hyungwoo; Jin, Joon-Hyung; Chang, Hochan; Park, Minjun; Lee, Han-Bo-Ram; Kim, Hyungjun; Lee, Byung Yang

    2015-01-01

    We demonstrate the selective adsorption of Ni/Si shell/core nanowires (Ni-Si NWs) with a Ni outer shell and a Si inner core on molecularly patterned substrates and their application to sensors for the detection of chlorine gas, a toxic halogen gas. The molecularly patterned substrates consisted of polar SiO2 regions and nonpolar regions of self-assembled monolayers of octadecyltrichlorosilane (OTS). The NWs showed selective adsorption on the polar SiO2 regions, avoiding assembly on the nonpolar OTS regions. Utilizing these assembled Ni-Si NWs, we demonstrate a sensor for the detection of chlorine gas. The utilization of Ni-Si NWs resulted in a much larger sensor response of approximately 23% to 5 ppm of chlorine gas compared to bare Ni NWs, due to the increased surface-to-volume ratio of the Ni-Si shell/core structure. We expect that our sensor will be utilized in the future for the real-time detection of halogen gases including chlorine with high sensitivity and fast response.

  16. Single particle optical investigation of gold shell enhanced upconverted fluorescence emission

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    Upconverting nanoparticles (UCNPs) excited in the near IR offer novel advantages as fluorescent contrast agents, allowing for background free bio-imaging. However, their fluorescence brightness is hampered by low quantum efficiency due to the low absorption cross section of Ytterbium and Erbium ions in the near IR. We enhance the efficiency of these particles by investigating the plasmonic coupling of 30nm diameter core NaYF4: Yb, Er upconverting particles (UCNPs) with a gold shell coating. An enhancement of green emission by a factor of five and a three times overall increase in emission intensity has been achieved for single particle spectra. UV-Vis absorption has confirmed the surface plasmon resonance (SPR) of the gold shell to the near IR and transmission electron microscope (TEM) images demonstrates successful growth of a gold shell around the upconversion particle. Time-resolved spectroscopy shows that gold shell coupling changes the lifetime of the energy levels of the Erbium ion that are relevant to the emission process.

  17. 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.

  18. 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. PMID:27405378

  19. 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

  20. Identification of Single-Locus PCR-Based Markers Linked to Shell Background Color in the Pacific Oyster (Crassostrea gigas).

    PubMed

    Ge, Jianlong; Li, Qi; Yu, Hong; Kong, Lingfeng

    2015-10-01

    A number of Pacific oyster (Crassostrea gigas) with golden shell background color were obtained which show great potential to develop a niche market. To improve the selective breeding progress of true-breeding strains with complete golden oysters, research was conducted to identify genetic markers linked to the shell color locus. An F1-segregating population was obtained by crossing two oysters with golden shell and white shell. Genomic DNA from eight progenies with golden shell and eight progenies with white shell were equally pooled for amplified fragment length polymorphism (AFLP) screening. In bulked segregant analysis, six out of 225 selective primer pair combinations produced seven polymorphic fragments tightly linked to shell color across the segregating population. The seven AFLP markers were all derived from the golden dam and mapped onto a single linkage group flanking the shell color locus. In conversion of the AFLPs into single-locus PCR-based markers, a sequence-characterized amplified region (SCAR) marker, named SCARJ8-2, a single nucleotide polymorphism (SNP) marker, named SNPL2-4, and a simple sequence repeat (SSR) marker, named SSRO11-2, were obtained. These markers obtained in this study will be useful for marker-assisted selection of the Pacific oyster.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    We study the hadroproduction of a W b 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. 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.

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

    DOE PAGES

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

    2016-06-06

    We study the hadroproduction of a W b 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 appliedmore » to the general case of matrix elements that feature coloured intermediate resonances and are matched to parton showers.« less

  4. Yolk-shell, hollow, and single-crystalline ZnCo(2)O(4) powders: preparation using a simple one-pot process and application in lithium-ion batteries.

    PubMed

    Choi, Seung Ho; Kang, Yun Chan

    2013-11-01

    The electrochemical properties of yolk-shell-structured, multi-component, transition-metal oxides have not yet been properly compared to those of hollow-structured or nanoscale powders. In this study, yolk-shell, hollow, and single-crystalline ZnCo2 O4 powders with uniform compositions are prepared by using simple gas-phase reaction methods. Double-shelled ZnCo2 O4 yolk-shell powder is prepared directly from the spray solution by using spray pyrolysis. Single-crystalline ZnCo2 O4 nanopowder is prepared by means of flame spray pyrolysis. The yolk-shell ZnCo2 O4 powder shows higher charge and discharge capacities than the hollow and single-crystalline powders. The yolk-shell, hollow, and single-crystalline ZnCo2 O4 powders deliver discharge capacities of 753, 586, and 206 mAh g(-1) , respectively, after 200 cycles at a charge/discharge rate of 3 A g(-1) , and the corresponding capacity retentions measured after the first cycle are 99, 74, and 27 %, respectively. The yolk-shell ZnCo2 O4 powders are structurally stable during cycling and have good electrochemical properties even at high current densities. PMID:23908071

  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. 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.

  7. Shell Perturbations of an Acoustic Thermometer Determined from Speed of Sound in Gas Mixtures

    NASA Astrophysics Data System (ADS)

    Gavioso, R. M.; Madonna Ripa, D.; Guianvarc'h, C.; Benedetto, G.; Giuliano Albo, P. A.; Cuccaro, R.; Pitre, L.; Truong, D.

    2010-09-01

    With the goal of achieving a better understanding of gas-shell coupling perturbations in the acoustic resonators used at INRiM for the determination of the Boltzmann constant, we measured the variation of their acoustic and microwave resonances induced by changing the composition of a binary He-Ar mixture which filled the cavity at constant temperature and pressure. As a consequence of the progressive dilution of a sample of initially pure He with Ar, the radial acoustic modes of the resonator spanned decreasing frequency intervals, partially overlapping, for several modes. In addition to the expected breathing mode of the shell, the results evidenced the presence of several other shell resonances at lower and higher frequencies, confirming that the elastic response of the assembled resonator significantly differs from that of a simple spherical shell. Experimental results are reported for two resonators which differ in design, dimensions, and constructing material. In spite of their being preliminary and susceptible of significant improvement, these results favor the interpretation of acoustic thermometry measurements with pure gases.

  8. 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.

  9. 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.

  10. Hanford single-shell tank waste-preliminary pretreatment testing of simulated waste

    SciTech Connect

    Jones, E.O.; Colton, N.G. ); Bloom, J.R. )

    1991-10-01

    Remediation and closure of the Single-Shell Tanks (SSTs) located on the Department of Energy's Hanford Site may depend on innovative waste removal, pretreatment and disposal technologies. This report describes preliminary studies conducted to support pretreatment processing of SST waste. This presentation looks specifically at the following types of activities: development, synthesis and characterization of a nonradioactive simulated SST waste; preliminary sequential dissolutions of simulated tank sludge; and thermochemical reduction of nitrate, a major component in SST waste. 7 refs., 4 figs., 6 tabs.

  11. 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.

  12. Analytical Derivations of Single-Particle Matrix Elements in Nuclear Shell Model

    NASA Astrophysics Data System (ADS)

    Fatah, Aziz H.; Radhi, R. A.; Abdullah, Nzar R.

    2016-07-01

    We present analytical method to calculate single particle matrix elements used in atomic and nuclear physics. We show seven different formulas of matrix elements of the operator f(r)dr m where f(r) = rμ, rμ jJ(qr), V(r) corresponding to the Gaussian and the Yukawa potentials used in nuclear shell models and nuclear structure. In addition, we take into account a general integral formula of the matrix element that covers all seven matrix elements obtained analytically.

  13. Experience with Aerosol Generation During Rotary Mode Core Sampling in the Hanford Single Shell Waste Tanks

    SciTech Connect

    SCHOFIELD, J.S.

    1999-08-31

    This document presents information on aerosol formation in tank head spaces during rotary mode core sampling (RMCS) from November 1994 through April 1999 in single shell waste tanks (SST) at the Hanford Site. The average tank head space mass concentration during RMCS has been 2.1E-5 g waste/m{sup 3}. The average mass of suspended solids present in a tank head space during RMCS has been 5.6E-2 g waste. The mass of waste sent to an exhauster during RMCS has averaged 5.3E-1 g waste per RMCS core and 8.3E-2 g waste per RMCS segment.

  14. Control of the binding energy by tuning the single dopant position, magnetic field strength and shell thickness in ZnS/CdSe core/shell quantum dot

    NASA Astrophysics Data System (ADS)

    Talbi, A.; Feddi, E.; Zouitine, A.; Haouari, M. El; Zazoui, M.; Oukerroum, A.; Dujardin, F.; Assaid, E.; Addou, M.

    2016-10-01

    Recently, the new tunable optoelectronic devices associated to the inclusion of the single dopant are in continuous emergence. Combined to other effects such as magnetic field, geometrical confinement and dielectric discontinuity, it can constitute an approach to adjusting new transitions. In this paper, we present a theoretical investigation of magnetic field, donor position and quantum confinement effects on the ground state binding energy of single dopant confined in ZnS/CdSe core/shell quantum dot. Within the framework of the effective mass approximation, the Schrödinger equation was numerically been solved by using the Ritz variational method under the finite potential barrier. The results show that the binding energy is very affected by the core/shell sizes and by the external magnetic field. It has been shown that the single dopant energy transitions can be controlled by tuning the dopant position and/or the field strength.

  15. 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.

  16. 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. PMID:25923841

  17. 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.

  18. Born-Infeld thin-shell wormholes supported by generalized Cosmic Chaplygin gas

    NASA Astrophysics Data System (ADS)

    Azam, M.

    2016-03-01

    This paper investigates thin-shell wormholes in Born-Infeld theory supported by generalized Cosmic Chaplygin gas (GCCG). We study their stability via radial perturbations for distinct values of charge and Born-Infeld parameter. The comparison of wormhole solutions corresponding to generalized Chaplygin gas, modified Chaplygin gas with GCCG quation of state is established. It is found that similar type of wormhole solutions exists for small value of charge and Born-Infeld parameter for all type of equation of state, while some extra stable as well as unstable solution are found corresponding to large value of charge and Born-Infeld parameter. Thus, it is concluded that GCCG and large value of charge may responsible for such extra solutions.

  19. 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.

  20. Analysis of organic carbon and moisture in Hanford single-shell tank waste

    SciTech Connect

    Toth, J.J.; Heasler, P.G.; Lerchen, M.E.; Hill, J.G.; Whitney, P.D.

    1995-05-01

    This report documents a revised analysis performed by Pacific Northwest Laboratory involving the organic carbon laboratory measurement data for Hanford single-shell tanks (SSTs) obtained from a review of the laboratory analytical data. This activity has as its objective to provide a best-estimate, including confidence levels, of total organic carbon (TOC) and moisture in each of the 149 SSTs at Hanford. The TOC and moisture information presented in this report is useful as part of the criteria to identify SSTs for additional measurements, or monitoring for the Organic Safety Program. In April 1994, an initial study of the organic carbon in Hanford single-shell tanks was completed at PNL. That study reflected the estimates of TOC based on tank characterizations datasets that were available at the time. Also in that study, estimation of dry basis TOC was based on generalized assumptions pertaining to the moisture of the tank wastes. The new information pertaining to tank moisture and TOC data that has become available from the current study influences the best estimates of TOC in each of the SSTs. This investigation of tank TOC and moisture has resulted in improved estimates based on waste phase: saltcake, sludge, or liquid. This report details the assumptions and methodologies used to develop the estimates of TOC and moisture in each of the 149 SSTs at Hanford.

  1. 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.

  2. Fiber density estimation from single q-shell diffusion imaging by tensor divergence.

    PubMed

    Reisert, Marco; Mader, Irina; Umarova, Roza; Maier, Simon; Tebartz van Elst, Ludger; Kiselev, Valerij G

    2013-08-15

    Diffusion-weighted magnetic resonance imaging provides information about the nerve fiber bundle geometry of the human brain. While the inference of the underlying fiber bundle orientation only requires single q-shell measurements, the absolute determination of their volume fractions is much more challenging with respect to measurement techniques and analysis. Unfortunately, the usually employed multi-compartment models cannot be applied to single q-shell measurements, because the compartment's diffusivities cannot be resolved. This work proposes an equation for fiber orientation densities that can infer the absolute fraction up to a global factor. This equation, which is inspired by the classical mass preservation law in fluid dynamics, expresses the fiber conservation associated with the assumption that fibers do not terminate in white matter. Simulations on synthetic phantoms show that the approach is able to derive the densities correctly for various configurations. Experiments with a pseudo ground truth phantom show that even for complex, brain-like geometries the method is able to infer the densities correctly. In-vivo results with 81 healthy volunteers are plausible and consistent. A group analysis with respect to age and gender show significant differences, such that the proposed maps can be used as a quantitative measure for group and longitudinal analysis.

  3. 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.

  4. Design of highly sensitive and selective Au@NiO yolk-shell nanoreactors for gas sensor applications.

    PubMed

    Rai, Prabhakar; Yoon, Ji-Wook; Jeong, Hyun-Mook; Hwang, Su-Jin; Kwak, Chang-Hoon; Lee, Jong-Heun

    2014-07-21

    Au@NiO yolk-shell nanoparticles (NPs) were synthesized by simple solution route and applied for efficient gas sensor towards H₂S gas. Carbon encapsulated Au (Au@C core-shell) NPs were synthesized by glucose-assisted hydrothermal method, whereas Au@NiO yolk-shell NPs were synthesized by precipitation method using Au@C core-shell NPs as a template. Sub-micrometer Au@NiO yolk-shell NPs were formed having 50-70 nm Au NPs at the periphery of NiO shell (10-20 nm), which was composed of 6-12 nm primary NiO particles. Au@NiO yolk-shell NPs showed higher response for H2S compared to other interfering gases (ethanol, p-xylene, NH₃, CO and H₂). The maximum response was 108.92 for 5 ppm of H₂S gas at 300 °C, which was approximately 19 times higher than that for the interfering gases. The response of Au@NiO yolk-shell NPs to H₂S was approximately 4 times higher than that of bare NiO hollow nanospheres. Improved performance of Au@NiO yolk-shell NPs was attributed to hollow spaces that allowed the accessibility of Au NPs to gas molecules. It was suggested that adsorption of H₂S on Au NPs resulted in the formation of sulfide layer, which possibly lowered its work function, and therefore tuned the electron transfer from Au to NiO rather NiO to Au, which leaded to increase in resistance and therefore response.

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

    NASA Astrophysics Data System (ADS)

    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.

    2014-09-01

    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.

  6. 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.; Pino, J. E.; Grim, G. P.; Remington, B. A.; Rowley, D. P.; Weber, S. V.; Barrios, M.; Benedetti, L. R.; et al

    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

  7. 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.

  8. 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.; 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.; Edwards, M. J.; Fittinghoff, D.; Glenn, S.; Haan, S. W.; Hamza, A.; and others

    2014-09-15

    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 T{sub 2}-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.

  9. Ultrasonic scattering cross sections of shell-encapsulated gas bubbles immersed in a viscoelastic liquid: first and second harmonics.

    PubMed

    Machado, João Carlos; Valente, Jefferson Silva

    2003-11-01

    The oscillations of gas bubbles, without shell, immersed in viscoelastic liquids and driven by an acoustic wave have been the subject of several investigations. They demonstrate that the viscosity coefficient and the spring constant of the liquid have significant influence on the scattering cross section of the gas bubble. For shell-encapsulated gas bubbles, the investigations have been concentrated to bubbles immersed in a pure viscous liquid. This present work computes the ultrasonic scattering cross section, first and second harmonics, of shell-encapsulated gas bubbles immersed in a viscoelastic liquid. The theoretical model of the bubble oscillation is based on the generalized Rayleigh-Plesset equation of motion of a spherical cavity immersed in a viscoelastic liquid represented by a three-parameter linear Oldroyd model. The scattering cross section is computed for Albunex type of bubble (shell thickness=15 nm, shell shear viscosity=1.77 Pas, shell modulus of rigidity=88.8 MPa) irradiated by a 3.5 MHz ultrasonic pressure wave with an amplitude of 30 kPa. The results demonstrate that encapsulated bubbles respond independently of the surrounding liquid being pure viscous or viscoelastic as long as the surrounding liquid shear viscosity is as low as 10(-3) Pas. Nevertheless, for higher shear viscosities, the bubble responds differently if the surrounding liquid is pure viscous or viscoelastic. In general, the scattering cross sections of first and second harmonics are larger for the viscoelastic liquid.

  10. Observation of shells in Coulomb explosions of rare-gas clusters

    SciTech Connect

    Erk, B.; Hoffmann, K.; Kandadai, N.; Helal, A.; Keto, J.; Ditmire, T.

    2011-04-15

    The explosions of noble gas clusters from argon and xenon irradiated by intense 35-fs infrared laser pulses have been studied. The kinetic energy spectra of ions produced in small clusters (<700 atoms) show a two-mode shell structure that is attributed to originating from a radial charge distribution. With a simple classical particle simulation of Coulomb explosions, the energy structure was reproduced using information on the arrangement of charge in the cluster. It was found that, during the explosion, the inner atoms of the clusters were less ionized than the outer atoms.

  11. Equivalence between local Fermi gas and shell models in inclusive muon capture from nuclei

    NASA Astrophysics Data System (ADS)

    Amaro, J. E.; Maieron, C.; Nieves, J.; Valverde, M.

    2005-06-01

    Motivated by recent studies of inclusive neutrino nucleus processes and muon capture within a correlated local Fermi gas model (LFG), we discuss the relevance of nuclear finite-size effects in these reactions at low energy, in particular for muon capture. To disentangle these effects from others coming from the reaction dynamics we employ here a simple uncorrelated shell model that embodies the typical finite-size content of the problem. The integrated decay widths of muon atoms calculated with this shell model are then compared for several nuclei with those obtained within the uncorrelated LFG, using in both models exactly the same theoretical ingredients and parameters. We find that the two predictions are in quite good agreement, within 1-7%, when the shell model density and the correct energy balance is used as input in the LFG calculation. The present study indicates that, despite the low excitation energies involved in the reaction, integrated inclusive observables, like the total muon capture width, are quite independent of the fine details of the nuclear wave functions.

  12. Results of gas monitoring of double-shell flammable gas watch list tanks

    SciTech Connect

    Wilkins, N.E.

    1995-01-19

    Tanks 103-SY; 101-AW; 103-, 104-, and 105-AN are on the Flammable Gas Watch List. Recently, standard hydrogen monitoring system (SHMS) cabinets have been installed in the vent header of each of these tanks. Grab samples have been taken once per week, and a gas chromatograph was installed on tank 104-AN as a field test. The data that have been collected since gas monitoring began on these tanks are summarized in this document.

  13. 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.

  14. Investigation of Photovoltaic Properties of Single Core-Shell GaN/InGaN Wires.

    PubMed

    Messanvi, A; Zhang, H; Neplokh, V; Julien, F H; Bayle, F; Foldyna, M; Bougerol, C; Gautier, E; Babichev, A; Durand, C; Eymery, J; Tchernycheva, M

    2015-10-01

    We report the investigation of the photovoltaic properties of core-shell GaN/InGaN wires. The radial structure is grown on m-plane {11̅00} facets of self-assembled c̅-axis GaN wires elaborated by metal-organic vapor phase epitaxy (MOVPE) on sapphire substrates. The conversion efficiency of wires with radial shell composed of thick In0.1Ga0.9N layers and of 30× In0.18Ga0.82N/GaN quantum wells are compared. We also investigate the impact of the contact nature and layout on the carrier collection and photovoltaic performances. The contact optimization results in an improved conversion efficiency of 0.33% and a fill factor of 83% under 1 sun (AM1.5G) on single wires with a quantum well-based active region. Photocurrent spectroscopy demonstrates that the response ascribed to the absorption of InGaN/GaN quantum wells appears at wavelengths shorter than 440 nm.

  15. Investigation of Photovoltaic Properties of Single Core-Shell GaN/InGaN Wires.

    PubMed

    Messanvi, A; Zhang, H; Neplokh, V; Julien, F H; Bayle, F; Foldyna, M; Bougerol, C; Gautier, E; Babichev, A; Durand, C; Eymery, J; Tchernycheva, M

    2015-10-01

    We report the investigation of the photovoltaic properties of core-shell GaN/InGaN wires. The radial structure is grown on m-plane {11̅00} facets of self-assembled c̅-axis GaN wires elaborated by metal-organic vapor phase epitaxy (MOVPE) on sapphire substrates. The conversion efficiency of wires with radial shell composed of thick In0.1Ga0.9N layers and of 30× In0.18Ga0.82N/GaN quantum wells are compared. We also investigate the impact of the contact nature and layout on the carrier collection and photovoltaic performances. The contact optimization results in an improved conversion efficiency of 0.33% and a fill factor of 83% under 1 sun (AM1.5G) on single wires with a quantum well-based active region. Photocurrent spectroscopy demonstrates that the response ascribed to the absorption of InGaN/GaN quantum wells appears at wavelengths shorter than 440 nm. PMID:26378593

  16. 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.

  17. Analysis of Induced Gas Released During Retrieval of Hanford Double-Shell Tank Waste

    SciTech Connect

    Wells, Beric E. ); Cuta, Judith M. ); Hartley, Stacey A. ); Mahoney, Lenna A. ); Meyer, Perry A. ); Stewart, Charles W. )

    2002-03-20

    Radioactive waste is scheduled to be retrieved from Hanford double-shell tanks AN-103, AN-104, AN-105 and AW-101 to the vitrification plant beginning about 2009. Retrieval may involve decanting the supernatant liquid and/or mixing the waste with jet pumps. In these four tanks, which contain relatively large volumes of retained gas, both of these operations are expected to induce buoyant displacement gas releases that can potentially raise the tank headspace hydrogen concentration to very near the lower flammability limit. This report describes the theory and detailed physical models for both the supernate decant and jet mixing processes and presents the results from applying the models to these operations in the four tanks. The technical bases for input parameter distributions are elucidated.

  18. Analysis of Induced Gas Releases During Retrieval of Hanford Double-Shell Tank Waste

    SciTech Connect

    Wells, Beric E. ); Cuta, Judith M. ); Hartley, Stacey A. ); Mahoney, Lenna A. ); Meyer, Perry A. ); Stewart, Charles W. )

    2002-09-25

    Radioactive waste is scheduled to be retrieved from Hanford double-shell tanks AN-103, AN-104, AN-105, and AW-101 to the vitrification plant beginning about 2009. Retrieval may involve decanting the supernatant liquid and/or mixing the waste with jet pumps. In these four tanks, which contain relatively large volumes of retained gas, both of these operations are expected to induce buoyant displacement gas releases that can potentially raise the tank headspace hydrogen concentration to very near the lower flammability limit. This report describes the theory and detailed physical models for both the supernatant decant and jet mixing processes and presents the results from applying the models to these operations in the four tanks. The technical bases for input parameter distributions are elucidated.

  19. Analysis of Induced Gas Releases During Retrieval of Hanford Double-Shell Tank Waste

    SciTech Connect

    Wells, Beric E.

    2003-02-19

    Checklist for Technical Peer Review for PNNL-13782 Rev. 1 as requested to ensure that software used to support the DSA is compliant with software QA requirements. Radioactive waste is scheduled to be retrieved from Hanford double-shell tanks AN-103, AN-104, AN-105 and AW-101 and transferred to the vitrification plant beginning in about 2009. Retrieval may involve decanting the supernatant liquid and/or mixing the waste with jet pumps. In these four tanks, which contain relatively large volumes of retained gas, both operations are expected to induce buoyant displacement gas releases that can potentially raise the tank headspace hydrogen concentration to a level very near the lower flammability limit. This report describes the theory and detailed physical models for both the supernatant decant and jet mixing processes and presents the results from applying the models to these operations in the four tanks. The technical bases for input parameter distributions are elucidated.

  20. 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

  1. 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.

  2. 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.

  3. Preliminary tank characterization report for single-shell tank 241-TY-102: best-basis inventory

    SciTech Connect

    Place, D.E.

    1997-06-01

    This document is a preliminary Tank Characterization Report (TCR). It only contains the current best-basis inventory (Appendix D) for single-shell tank 241-TY-102. 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.

  4. 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.

  5. Tank characterization report for single-shell tank 241-BY-107

    SciTech Connect

    Mccain, D.J.

    1997-04-09

    One major function 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 and other 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-BY-107. The objectives of this report are (1) to use characterization data in response to technical issues associated with 241-BY-107 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 provides the best-basis inventory estimate, and Section 4.0 makes recommendations about the safety status and additional sampling needs. The appendices contain supporting data and information.

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

    PubMed Central

    2010-01-01

    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. PMID:20802786

  7. 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.

  8. Enhanced gas sensing properties of multiple networked In2O3-core/ZnO-shell nanorod sensors.

    PubMed

    Park, Sunghoon; Kim, Hyunsu; Jin, Changhyun; Lee, Chongmu

    2013-05-01

    The influence of the encapsulation of In2O3 nanorods with ZnO on the H2S gas sensing properties was studied. In2O3-core/ZnO-shell nanorods were fabricated by a two step process comprising the thermal evaporation of an 1:1 mixture of In2O3 and graphite powders and the atomic layer deposition of ZnO. The core-shell nanorods ranged from 100 to 200 nm in diameter and were up to a few hundreds of micrometers in length. The thickness of the ZnO shell layer in the core-shell nanorod ranged from 5 to 10 nm. Multiple networked In2O3-core/ZnO-shell nanorod sensors showed the response of more or less 4 times higher than bare In2O3 nanorod sensors to H2S in a concentration range of 10-100 ppm at 300 degrees C. The substantial improvement in the response of In2O3 nanorods to H2S gas by the encapsulation with ZnO can be accounted for based on the space-charge model. Besides the enhanced sensor response, both the response and recovery times of the core-shell nanorods were shorter than those of the bare-In2O3 nanorods for any H2S concentration, respectively. PMID:23858872

  9. 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

  10. 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.

  11. Load requirements for maintaining structural integrity of Hanford single-shell tanks during waste feed delivery and retrieval activities

    SciTech Connect

    JULYK, L.J.

    1999-09-22

    This document provides structural load requirements and their basis for maintaining the structural integrity of the Hanford Single-Shell Tanks during waste feed delivery and retrieval activities. The requirements are based on a review of previous requirements and their basis documents as well as load histories with particular emphasis on the proposed lead transfer feed tanks for the privatized vitrification plant.

  12. Size-controlled synthesis of thermal stable single-cored Ru@H-SiO2 core-shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Yu, Xiaolong; Yu, Hongbo; Lim, Zi-Yian; Yang, Guangming; Xie, Zhaohui; Zhou, Shenghu; Yin, Hongfeng

    2016-06-01

    Single-cored Ru@H-SiO2 (H: hollow) core-shell nanoparticles (NPs) with around 4.3 nm Ru cores and hollow SiO2 shells were prepared successfully. In this synthetic process, we obtained multi-cored Ru@SiO2 NPs initially, single-cored RuO2@H-SiO2 NPs during treatment, and single-cored Ru@H-SiO2 NPs in the end. The Ru@SiO2 NPs were prepared by water-in-oil microemulsion method, and the size and core number of Ru@SiO2 NPs can be controlled. Single-cored RuO2@H-SiO2 NPs and Ru@H-SiO2 NPs were successively obtained by calcination and reduction. The structure showed promising aggregate-resistant performance and potential application in catalysis.

  13. Synthesis of micro-sized shell-isolated 3D plasmonic superstructures for in situ single-particle SERS monitoring

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Zhao, Jingjing; Ji, Ji; Liu, Baohong

    2016-04-01

    A single-particle SERS system enabling real-time and in situ observation of Au-catalyzed reactions has been developed. Both the catalytic activity and the SERS effect are coupled into a single bi-functional 3D superstructure comprising Au nanosatellites self-assembled onto a shell-insulated Ag microflower core, which eliminates the interference from photocatalysis.A single-particle SERS system enabling real-time and in situ observation of Au-catalyzed reactions has been developed. Both the catalytic activity and the SERS effect are coupled into a single bi-functional 3D superstructure comprising Au nanosatellites self-assembled onto a shell-insulated Ag microflower core, which eliminates the interference from photocatalysis. Electronic supplementary information (ESI) available: Details of the synthesis and characterization of the Ag@SiO2@Au superstructures (SEM and TEM images, UV/vis and SERS spectra). See DOI: 10.1039/c6nr00278a

  14. 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

  15. 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

  16. Morphology and Oxide Shell Structure of Iron Nanoparticles Grown by Sputter-Gas-Aggregation

    SciTech Connect

    Wang, Chong M.; Baer, Donald R.; Amonette, James E.; Engelhard, Mark H.; Qiang, You; Antony, Jiji

    2007-06-27

    Much recent research effort has been made on the synthesis, characterization, and property evaluation of core-shell structured Fe nanoparticles. Fundamental properties of these particles depend on both their external crystal faceting planes and the nature of a protective oxide layer. In this paper, the crystal faceting planes and oxide coating structures of core-shell structured iron/iron oxide nanoparticles synthesized by a sputter-gas-aggregation process were studied using transmission electron microscopy (TEM), electron diffraction and Wulff shape construction. The particles grown by this process and deposited on a support at room temperature process have been compared with particles grown and deposited at high temperature as reported in literature. Most synthesis processes produce round particles for particles less than 20 nm in diameter. For larger particles crystallographic facets are observed. It has been found that the Fe nanoparticles formed at RT are invariantly faceted on the {100} lattice planes and truncated by the {110} planes at different degrees. Substantial fraction of particles are confined only by the 6 {100} planes (not truncated by the {110} planes), this contrasts with the Fe particles formed at high temperature (HT) for which a predominance of {110} planes has been reported. Furthermore, at RT no particle was identified to be only confined by the 12 {110} planes which is relatively common for the particles formed at HT. The Fe cubes defined by the 6 {100} planes show a characteristic inward relaxation along the <100> and <110> directions and the reason for this behavior is not fully understood. The oxide shell on the Fe {100} plane maintains an orientation relationship: Fe(001)//Fe3O4(001) and Fe[100]//Fe3O4[110], which is same as the oxide formed on a bulk Fe(001) through thermal oxidation. Orientation of the oxide that forms on the Fe{110} facets differs from that on Fe{001}, therefore, properties of core-shell structured Fe nanoparticle

  17. Germanium-silicon alloy and core-shell nanocrystals by gas phase synthesis.

    PubMed

    Mehringer, Christian; Kloner, Christian; Butz, Benjamin; Winter, Benjamin; Spiecker, Erdmann; Peukert, Wolfgang

    2015-03-12

    In this work we present a novel route to synthesize well defined germanium-silicon alloy (GexSi1-x) and core-shell nanocrystals (NCs) employing monosilane (SiH4) and monogermane (GeH4) as precursors in a continuously operated two-stage hot-wall aerosol reactor setup. The first hot-wall reactor stage (HWR I) is used to produce silicon (Si) seed particles from SiH4 pyrolysis in Argon (Ar). The resulting seeding aerosol is fed into the second reactor stage (HWR II) and a mixture of SiH4 and GeH4 is added. The ratio of the precursors in the feed, their partial pressures, the synthesis temperature in HWR II and the overall pressure are varied depending on the desired morphology and composition. Alloy particle production is achieved in the heterogeneous surface reaction regime, meaning that germanium (Ge) and Si are deposited on the seed surface simultaneously. The NCs can be synthesized with any desired composition, whilst maintaining a mean diameter around 30 nm with a geometric standard deviation (GSD) around 1.25. The absorption behavior and the related fundamental optical band gap energy in dependence on the alloy composition are exemplarily presented. They prove the possibility to tailor NC properties for electronical and opto-electronical applications. In the homogeneous gas phase reaction regime facetted Ge-Si core-shell structures are accessible. The Ge deposition on the seeds precedes the Si deposition due to different gas phase reaction kinetics of the precursors. The Si layer grows epitaxially on the Ge core and is around 5 nm thick. PMID:25700152

  18. Germanium-silicon alloy and core-shell nanocrystals by gas phase synthesis.

    PubMed

    Mehringer, Christian; Kloner, Christian; Butz, Benjamin; Winter, Benjamin; Spiecker, Erdmann; Peukert, Wolfgang

    2015-03-12

    In this work we present a novel route to synthesize well defined germanium-silicon alloy (GexSi1-x) and core-shell nanocrystals (NCs) employing monosilane (SiH4) and monogermane (GeH4) as precursors in a continuously operated two-stage hot-wall aerosol reactor setup. The first hot-wall reactor stage (HWR I) is used to produce silicon (Si) seed particles from SiH4 pyrolysis in Argon (Ar). The resulting seeding aerosol is fed into the second reactor stage (HWR II) and a mixture of SiH4 and GeH4 is added. The ratio of the precursors in the feed, their partial pressures, the synthesis temperature in HWR II and the overall pressure are varied depending on the desired morphology and composition. Alloy particle production is achieved in the heterogeneous surface reaction regime, meaning that germanium (Ge) and Si are deposited on the seed surface simultaneously. The NCs can be synthesized with any desired composition, whilst maintaining a mean diameter around 30 nm with a geometric standard deviation (GSD) around 1.25. The absorption behavior and the related fundamental optical band gap energy in dependence on the alloy composition are exemplarily presented. They prove the possibility to tailor NC properties for electronical and opto-electronical applications. In the homogeneous gas phase reaction regime facetted Ge-Si core-shell structures are accessible. The Ge deposition on the seeds precedes the Si deposition due to different gas phase reaction kinetics of the precursors. The Si layer grows epitaxially on the Ge core and is around 5 nm thick.

  19. Size-controlled, magnetic, and core-shell nanoparticles synthesized by inert-gas condensation

    NASA Astrophysics Data System (ADS)

    Koten, Mark A.

    Interest in nanoparticles (2 to 100 nm in diameter) and clusters of atoms (0.5 to 2 nm in diameter) has heightened over the past two and a half decades on both fundamental and functional levels. Nanoparticles and clusters of atoms are an exciting branch of materials science because they do not behave like normal bulk matter, nor do they act like molecules. They can have shockingly different physical, chemical, optical, or magnetic properties from the same material at a larger scale. In the case of nanoparticles, the surface-to-volume ratio can change fundamental properties like melting temperature, binding energy, or electron affinity. The definitions of markers used to distinguish between metallic, semiconducting, and insulating bulk condensed matter, such as the band gap and polarizability, can even be blurred or confused on the nanoscale. Similarly, clusters of atoms can form in structures that are only stable at finite sizes, and do not translate to bulk condensed matter. Thermodynamics of finite systems changes dramatically in nanovolumes such as wires, rods, cubes, and spheres, which can lead to complex core-shell and onion-like nanostructures. Consequently, these changes in properties and structure have led to many new possibilities in the field of materials engineering. Inert-gas condensation (IGC) is a well-established method of producing nanoparticles that condense from the gas phase. Its first use dates back to the early 1990s, and it has been used to fabricate nanoparticles both commercially and in research and development for applications in magnetism, biomedicine, and catalysts. In this dissertation, IGC was used to produce a wide variety of nanoparticles. First, control over the size distributions of Cu nanoparticles and how it relates to the plasma properties inside the nucleation chamber was investigated. Next, the formation of phase pure WFe2 nanoparticles revealed that this Laves phase is ferromagnetic instead of non-magnetic. Finally, core-shell

  20. Shell thickness dependent photoinduced hole transfer in hybrid conjugated polymer/quantum dot nanocomposites: from ensemble to single hybrid level.

    PubMed

    Xu, Zhihua; Hine, Corey R; Maye, Mathew M; Meng, Qingping; Cotlet, Mircea

    2012-06-26

    Photoinduced hole transfer is investigated in inorganic/organic hybrid nanocomposites of colloidal CdSe/ZnS quantum dots and a cationic conjugated polymer, poly(9,9'-bis(6-N,N,N-trimethylammoniumhexyl)fluorene-alt-phenylene, in solution and in solid thin film, and down to the single hybrid level and is assessed to be a dynamic quenching process. We demonstrate control of hole transfer rate in these quantum dot/conjugated polymer hybrids by using a series of core/shell quantum dots with varying shell thickness, for which a clear exponential dependency of the hole transfer rate vs shell thickness is observed, for both solution and thin-film situations. Furthermore, we observe an increase of hole-transfer rate from solution to film and correlate this with changes in quantum dot/polymer interfacial morphology affecting the hole transfer rate, namely, the donor-acceptor distance. Single particle spectroscopy experiments reveal fluctuating dynamics of hole transfer at the single conjugated polymer/quantum dot interface and an increased heterogeneity in the hole-transfer rate with the increase of the quantum dot's shell thickness. Although hole transfer quenches the photoluminescence intensity of quantum dots, it causes little or no effect on their blinking behavior over the time scales probed here.

  1. Design of highly sensitive and selective Au@NiO yolk-shell nanoreactors for gas sensor applications

    NASA Astrophysics Data System (ADS)

    Rai, Prabhakar; Yoon, Ji-Wook; Jeong, Hyun-Mook; Hwang, Su-Jin; Kwak, Chang-Hoon; Lee, Jong-Heun

    2014-06-01

    Au@NiO yolk-shell nanoparticles (NPs) were synthesized by simple solution route and applied for efficient gas sensor towards H2S gas. Carbon encapsulated Au (Au@C core-shell) NPs were synthesized by glucose-assisted hydrothermal method, whereas Au@NiO yolk-shell NPs were synthesized by precipitation method using Au@C core-shell NPs as a template. Sub-micrometer Au@NiO yolk-shell NPs were formed having 50-70 nm Au NPs at the periphery of NiO shell (10-20 nm), which was composed of 6-12 nm primary NiO particles. Au@NiO yolk-shell NPs showed higher response for H2S compared to other interfering gases (ethanol, p-xylene, NH3, CO and H2). The maximum response was 108.92 for 5 ppm of H2S gas at 300 °C, which was approximately 19 times higher than that for the interfering gases. The response of Au@NiO yolk-shell NPs to H2S was approximately 4 times higher than that of bare NiO hollow nanospheres. Improved performance of Au@NiO yolk-shell NPs was attributed to hollow spaces that allowed the accessibility of Au NPs to gas molecules. It was suggested that adsorption of H2S on Au NPs resulted in the formation of sulfide layer, which possibly lowered its work function, and therefore tuned the electron transfer from Au to NiO rather NiO to Au, which leaded to increase in resistance and therefore response.Au@NiO yolk-shell nanoparticles (NPs) were synthesized by simple solution route and applied for efficient gas sensor towards H2S gas. Carbon encapsulated Au (Au@C core-shell) NPs were synthesized by glucose-assisted hydrothermal method, whereas Au@NiO yolk-shell NPs were synthesized by precipitation method using Au@C core-shell NPs as a template. Sub-micrometer Au@NiO yolk-shell NPs were formed having 50-70 nm Au NPs at the periphery of NiO shell (10-20 nm), which was composed of 6-12 nm primary NiO particles. Au@NiO yolk-shell NPs showed higher response for H2S compared to other interfering gases (ethanol, p-xylene, NH3, CO and H2). The maximum response was 108.92 for 5 ppm

  2. FRACTIONAL CRYSTALLIZATION OF HANFORD SINGLE SHELL TANK (SST) WASTES A MODELING APPROACH

    SciTech Connect

    HAMILTON, D.W.

    2006-12-21

    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 U.S. Department of Energy (DOE), the Environmental Protection Agency, and Washington State. Water will be used to retrieve the wastes and the resulting solution will be pumped to the proposed treatment 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.

  3. 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.''

  4. 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).

  5. 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).

  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-C-106

    SciTech Connect

    Schreiber, R.D.

    1996-09-25

    This tank characterization report summarizes information on the historical uses, current status, and sampling and analysis results of waste stored in single-shell underground tank 241-C-106. This report supports the requirements of the Hanford Federal Facility Agreement and Consent Order, Milestone M-44-09 (Ecology et al. 1996). Tank 241-C-106 is the only tank on the High-Heat Load Watch List. As a result of the analyses addressed by this report, the supernate and upper 60 percent of the sludge in the tank do not pose any safety concerns in addition to the high-heat load issue based on the decision limits of the safety screening data quality objective (DQO) (Dukelow et al. 1995). The lower 40 percent of the sludge was not sampled; therefore, no statements regarding the safety of this waste can be made. A portion of the tank sludge is scheduled to be retrieved in fiscal year 1997 in order to mitigate the high-heat load in the tank.

  8. 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.

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

    SciTech Connect

    Jo, J.

    1997-04-15

    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 appendixes serve as the TCR for single-shell tank 241-S-104. The objectives of this report are: (1) to use characterization data in response to technical issues associated with 241-S- 104 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 appendixes. This report also supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1996) milestone M-44-05.

  10. 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).

  11. Synthesis and characterization of amino-functionalized single magnetic core-silica shell composites

    NASA Astrophysics Data System (ADS)

    Zhu, Zhanwang; Wei, Xinlin; Xu, Feng; Wang, Yuanfeng

    2012-10-01

    The thermal decomposition approach, reverse micro-emulsion system and surface modification technique had been successfully used to synthesis single magnetic core Fe3O4@Organic Layer@SiO2-NH2 complex microspheres. The magnetization of the magnetic microspheres core could be easily tuned between 28 and 56 emu/g by adjusting the amount of 2-mercaptobarbituric acid. It was found that the Organic Layer to some extent had a protective effect on avoiding Fe3O4 being oxidized into Fe2O3. Each Fe3O4@Organic Layer microsphere could be coated uniformly by about 30 nm of silica shell. The average diameter of the Fe3O4@Organic Layer@SiO2 composites was about 538 nm. The saturation magnetization of the Fe3O4@Organic Layer@SiO2 complex microspheres was 12.5% less than magnetic microspheres cores. The Fe3O4@Organic Layer@SiO2-NH2 composites possessed a huge application potentiality in specificity enriching and separating biological samples.

  12. 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.

  13. 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.''

  14. 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.``

  15. 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).

  16. 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.

  17. 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).

  18. Tank characterization report for single-shell tank 241-T-105

    SciTech Connect

    Field, J.G.

    1998-06-18

    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-105. The objectives of this report are (1) to use characterization data in response to technical issues associated with tank 241-T-105 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``.

  19. Tank characterization report for single-shell tank 241-S-111

    SciTech Connect

    Conner, J.M.

    1997-04-28

    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-S-111. The objectives of this report are: (1) to use characterization data to address technical issues associated with tank 241-S-111 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. This report also supports the requirements of Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1996) milestone M-44-10.

  20. 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).

  1. Tank characterization report for single-shell tank 241-U-106

    SciTech Connect

    Brown, T.M.

    1997-04-15

    One major function 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, 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-106. The objectives of this report are: (1) to use characterization data in response to technical issues associated with tank 241-U-106 waste, and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. Section 2.0 of this report 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. The appendixes contain supporting data and information. This report also supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ikology et al. 1996), Milestone M-44-10.

  2. 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.

  3. Vibration of a single microcapsule with a hard plastic shell in an acoustic standing wave field.

    PubMed

    Koyama, Daisuke; Kotera, Hironori; Kitazawa, Natsuko; Yoshida, Kenji; Nakamura, Kentaro; Watanabe, Yoshiaki

    2011-04-01

    Observation techniques for measuring the small vibration of a single microcapsule of tens of nanometers in an acoustic standing wave field are discussed. First, simultaneous optical observation of a microbubble vibration by two methods is investigated, using a high-speed video camera, which permits two-dimensional observation of the bubble vibration, and a laser Doppler vibrometer (LDV), which can observe small bubble vibration amplitudes at high frequency. Bubbles of tens of micrometers size were trapped at the antinode of an acoustic standing wave generated in an observational cell. Bubble vibration at 27 kHz could be observed and the experimental results for the two methods showed good agreement. The radial vibration of microcapsules with a hard plastic shell was observed using the LDV and the measurement of the capsule vibration with radial oscillation amplitude of tens of nanometers was successful. The acoustic radiation force acting on microcapsules in the acoustic standing wave was measured from the trapped position of the standing wave and the radial oscillation amplitude of the capsules was estimated from the theoretical equation of the acoustic radiation force, giving results in good agreement with the LDV measurements. The radial oscillation amplitude of a capsule was found to be proportional to the amplitude of the driving sound pressure. A larger expansion ratio was observed for capsules closer to the resonance condition under the same driving sound pressure and frequency.

  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 Tank 241-T-107

    SciTech Connect

    Valenzuela, B.D.; Jensen, L.

    1994-09-01

    Single shell tank 241-T-107 is a Hanford Site Ferrocyanide Watch List tank most recently sampled in March 1993. Analyses of materials obtained from tank T-107 were conducted to support the Ferrocyanide Unreviewed Safety Question (USQ) and the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-10-06 as well as Milestones M-44-05 and M-44-07. Characterization of the tank waste T-107 will support the ferrocyanide safety issue in order to classify the tank as safe, conditionally safe, or unsafe. This tank characterization report expands on the data found in Ferrocyanide Safety Program: Data Interpretation Report for Tank 241-T-107 Core Samples. Analysis of core samples obtained from tank T-107 strongly indicate the cyanide and oxidizer (nitrate/nitrite) concentrations in the tank waste are not significant enough to support a self-sustaining exothermic reaction. Therefore, the contents of tank T-107 present no imminent threat to the workers at the Hanford Site, the public, or the environment. Because the possibility of an exothermic reaction is remote, the consequences of an accident scenario, as proposed by the General Accounting Office, are not applicable.

  6. 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.

  7. The fractal dimension of cell membrane correlates with its capacitance: A new fractal single-shell model

    SciTech Connect

    Wang Xujing; Becker, Frederick F.; Gascoyne, Peter R. C.

    2010-12-15

    The scale-invariant property of the cytoplasmic membrane of biological cells is examined by applying the Minkowski-Bouligand method to digitized scanning electron microscopy images of the cell surface. The membrane is found to exhibit fractal behavior, and the derived fractal dimension gives a good description of its morphological complexity. Furthermore, we found that this fractal dimension correlates well with the specific membrane dielectric capacitance derived from the electrorotation measurements. Based on these findings, we propose a new fractal single-shell model to describe the dielectrics of mammalian cells, and compare it with the conventional single-shell model (SSM). We found that while both models fit with experimental data well, the new model is able to eliminate the discrepancy between the measured dielectric property of cells and that predicted by the SSM.

  8. 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

  9. Isolating scattering resonances of an air-filled spherical shell using iterative, single-channel time reversal.

    PubMed

    Waters, Zachary J; Dzikowicz, Benjamin R; Simpson, Harry J

    2012-01-01

    Iterative, single-channel time reversal is employed to isolate backscattering resonances of an air-filled spherical shell in a frequency range of 0.5-20 kHz. Numerical simulations of free-field target scattering suggest improved isolation of the dominant target response frequency in the presence of varying levels of stochastic noise, compared to processing returns from a single transmission and also coherent averaging. To test the efficacy of the technique in a realistic littoral environment, monostatic scattering experiments are conducted in the Gulf of Mexico near Panama City, Florida. The time reversal technique is applied to returns from a hollow spherical shell target sitting proud on a sandy bottom in 14 m deep water. Distinct resonances in the scattering response of the target are isolated, depending upon the bandwidth of the sonar system utilized.

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

    PubMed

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

    2015-08-28

    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.

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

    PubMed

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

    2015-08-28

    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. PMID:26203627

  12. 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.

  13. Appurtenance Influence on Type III Hanford Single-Shell Tank Structural Integrity - 12255

    SciTech Connect

    Sanborn, Scott E.; Johnson, Kenneth I.; Larsen, Brian M.; Julyk, Larry J.

    2012-07-01

    The interim stabilized Hanford Single-Shell Tanks (SSTs) are currently undergoing a state of the art analysis to assess the structural integrity of the waste storage tanks, for cleanup and closure operations, considering their adverse thermal histories and an updated seismic hazard for the Hanford Site near Richland, Washington. The SSTs contain a variety of ancillary pits, piping, piping supports, risers, equipment, and penetrations known as appurtenances. These appurtenances may alter the structural response and ultimately could affect the structural integrity of the SSTs. An important challenge to the structural analysis of the SSTs is to determine the impact of these appurtenances on structural integrity. To achieve this, the various appurtenances were reviewed and a bounding appurtenance configuration for the SST Type III tanks was analyzed using finite element models for both thermal and operating loads as well as seismic loads. Tank structural demands from the finite element analyses were evaluated according to American Concrete Institute (ACI-349) code requirements to determine the tank structural integrity. The appurtenances configuration is found to increase the demand to capacity ratios in local regions near the appurtenances. Away from the appurtenances the influence on structural integrity is minor. The ACI-349-06 evaluation of the Type III SST bounding appurtenance configuration shows the tank is still structurally sound under all evaluated load combinations. When the appurtenance model D/C ratios were compared to those from the baseline axisymmetric model it was found that there were significant differences in the results, particularly under seismic loading conditions. This indicates that the effect of appurtenances on tank structural integrity should at least be considered in all SST AORs. (authors)

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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…

  20. Best-basis estimates of solubility of selected radionuclides in sludges in Hanford single-shell tanks

    SciTech Connect

    HARMSEN, R.W.

    1999-02-24

    The Hanford Defined Waste (HDW) model (Rev. 4) (Agnew et al. 1997) projects inventories (as of January 1, 1994) of 46 radionuclides in the Hanford Site underground waste storage tanks. To model the distribution of the 46 radionuclides among the 177 tanks, it was necessary for Agnew et al. to estimate the solubility of each radionuclide in the various waste types originally added to the single-shell tanks. Previous editions of the HDW model used single-point solubility estimates. The work described in this report was undertaken to provide more accurate estimates of the solubility of all 46 radionuclides in the various wastes.

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. 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

    2016-01-01

    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

  6. 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.

  7. 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

  8. DEPLOYING TECHNOLOGY ADVANCEMENTS FOR CHARACTERIZING THE VADOSE ZONE IN SINGLE-SHELL TANK WASTE MANAGEMENT AREAS

    SciTech Connect

    EBERLEIN SJ; SYDNOR HA; DA MYERS

    2010-01-14

    As much as one million gallons of waste is believed to have leaked from tanks, pipelines or other equipment in the single-shell tank farm waste management areas (WMAs) within the 200 East and West areas of the U.S. Department of Energy's Hanford Site near Richland, Washington. Although some contamination has reached groundwater, most contamination still resides in the vadose zone. The magnitude ofthis problem requires new approaches for soil characterization if we are to understand the nature and extent of the contamination and take action to protect the enviromnent. Because of the complexity and expense of drilling traditional boreholes in contaminated soil, direct push characterization using a hydraulic hammer has been extensively employed. Direct push probe holes <3-inch diameter have been pushed to a maximum depth of 240 feet below ground surface in 200 East area. Previously gross gamma and moisture logging of these narrow probe holes was perfonned to identify the location of cesium-137 ({sup 137}Cs) (which has limited mobility in Hanford soil) and moisture peaks. Recently a bismuth germinate detector has been deployed for detecting and quantifying the spectrum of cobalt-60 ({sup 60}Co) (a more mobile contaminant), which provides additional information. The direct push system is configured to allow the collection ofmultiple soil core samples throughout the depth ofthe probe hole. The direct push unit has been used to place individual electrodes at a variety of depths as the probe hole is being decommissioned. These deep electrodes enable the use of soil resistivity measurement methods between surface and deep electrodes as-well-as between sets of deep electrodes. Initial testing of surface-to-deep electrode resistivity measurements in WMA C demonstrated significant improvement in defining the three dimensional extent of a contamination plume. A multiple-electrode string is presently being developed to further enhance the resolution of resistivity data. The

  9. Multi-function waste tank facility path forward engineering analysis technical task 3.3, single-shell tank liquid contents

    SciTech Connect

    Brown, R.G.; Mattichak, R.W.

    1995-04-28

    Results are reported on actions taken to determine the quantity of liquid wastes in the single shell tanks that still need stabilization, and to determine the amount of flush water needed to support the stabilization effort.

  10. 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.

  11. Single-field inflation à la generalized Chaplygin gas

    SciTech Connect

    Campo, Sergio del

    2013-11-01

    In the simplest scenario for inflation, i.e. in the single-field inflation, it is presented an inflaton field with properties equivalent to a generalized Chaplygin gas. Their study is performed using the Hamilton-Jacobi approach to cosmology. The main results are contrasted with the measurements recently released by the Planck data, combined with the WMAP large-angle polarization. If the measurements released by Planck for the scalar spectral index together with its running are taken into account it is found a value for the α-parameter associated to the generalized Chaplygin gas given by α = 0.2578±0.0009.

  12. Gas sampling and analysis results for demilitarization of M107, 155mm artillery shells by open detonation

    SciTech Connect

    Velsko, C., LLNL

    1997-11-01

    This report presents and evaluates the gas sampling and analysis data obtained by LLNL for the fourdemilitarization experiments executed in the contained underground facility at X tunnel of the Nevada Test Site (NTS) from December 1996 through March 1997. Each of the four experiments detonated M107, 155mm artillery shells, 6, 24, 24 and 60 respectively, using C4 donor charges, and produced combustion product gases which mixed with the air and tracer gases in the chamber. Bechtel Nevada personnel performed the sampling configuration setup and operation of the field gas sampling and field analysis instrumentation. Continuous sampling and on-line analysis of gas from the chamber, as well as discrete sampling into 1 liter containers for post-shot analysis at LLNL, provided data to determine the gas compostion at detonation zero time. The carbon balance and emission factors of gaseous species produced by open detonation (OD) of M107 shells with C4 donor charges are presented and compared to OD of unconfined composition B explosive. The emission factors (EFs) for fixed gases from each test inthis series can be scaled as a function of net explosive weight (NEW) to estimate the amounts of gasesgenerated in 10,000 pound NEW demilitarization events. Changes in the trace gas concentrationsresulting from modification of the detonation setup can be used to monitor the extent of optimization.

  13. Continuous-wave pumping of multiexciton bands in the photoluminescence spectrum of a single CdTe-CdSe core-shell colloidal quantum dot.

    PubMed

    Osovsky, Ruth; Cheskis, Dima; Kloper, Viki; Sashchiuk, Aldona; Kroner, Martin; Lifshitz, Efrat

    2009-05-15

    Single-exciton, biexciton, triexciton, and quadraexciton bands were resolved in the microphotoluminescence spectrum of a single CdTe/CdSe core-shell colloidal quantum dot, revealing nearly blinking-free behavior. Multiexcitons were generated by a sequential filling of electronic shells with the increase of a continuous-wave excitation power, and their probability was evaluated under steady-state conditions. A partial carriers' delocalization was determined at the core-shell interface, and an exciton binding energy was estimated by a second-order perturbation theory.

  14. 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.

  15. 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

  16. The effect of gradients at stagnation on K-shell x-ray line emission in high-current Ar gas-puff implosions

    SciTech Connect

    Jones, B. Harvey-Thompson, A. J.; Ampleford, D. J.; Jennings, C. A.; Hansen, S. B.; Moore, N. W.; Lamppa, D. C.; Johnson, D.; Jones, M. C.; Waisman, E. M.; Coverdale, C. A.; Cuneo, M. E.; Rochau, G. A.; Apruzese, J. P.; Giuliani, J. L.; Thornhill, J. W.; Ouart, N. D.; Chong, Y. K.; Velikovich, A. L.; Dasgupta, A.; and others

    2015-02-15

    Argon gas puffs have produced 330 kJ ± 9% of x-ray radiation above 3 keV photon energy in fast z-pinch implosions, with remarkably reproducible K-shell spectra and power pulses. This reproducibility in x-ray production is particularly significant in light of the variations in instability evolution observed between experiments. Soft x-ray power measurements and K-shell line ratios from a time-resolved spectrum at peak x-ray power suggest that plasma gradients in these high-mass pinches may limit the K-shell radiating mass, K-shell power, and K-shell yield from high-current gas puffs.

  17. 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.

  18. Single-shell carbon-encapsulated iron nanoparticles: synthesis and high electrocatalytic activity for hydrogen evolution reaction.

    PubMed

    Tavakkoli, Mohammad; Kallio, Tanja; Reynaud, Olivier; Nasibulin, Albert G; Johans, Christoffer; Sainio, Jani; Jiang, Hua; Kauppinen, Esko I; Laasonen, Kari

    2015-04-01

    Efficient hydrogen evolution reaction (HER) through effective and inexpensive electrocatalysts is a valuable approach for clean and renewable energy systems. Here, single-shell carbon-encapsulated iron nanoparticles (SCEINs) decorated on single-walled carbon nanotubes (SWNTs) are introduced as a novel highly active and durable non-noble-metal catalyst for the HER. This catalyst exhibits catalytic properties superior to previously studied nonprecious materials and comparable to those of platinum. The SCEIN/SWNT is synthesized by a novel fast and low-cost aerosol chemical vapor deposition method in a one-step synthesis. In SCEINs the single carbon layer does not prevent desired access of the reactants to the vicinity of the iron nanoparticles but protects the active metallic core from oxidation. This finding opens new avenues for utilizing active transition metals such as iron in a wide range of applications. PMID:25683139

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Tank characterization report for single-shell tank 241-T-102

    SciTech Connect

    Baldwin, J.H.

    1997-06-24

    A major function 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 appendixes serve as the TCR for single-shell tank 241-T-102. The objectives of this report are to use characterization data in response to technical issues associated with tank 241-T-102 waste; and 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 appendixes. This report 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. The most recent core sampling of tank 241-T-102 (March 1993) predated the existence of data quality objectives (DQOs). An assessment of the technical issues from the currently applicable DQOs was made using data from the 1993 push mode core sampling event, a July 1994 grab sampling event, and a May 1996 vapor flammability measurement. Historical information for tank 241-T-102, provided in Appendix A, includes surveillance information, records pertaining to waste transfers and tank operations, and expected tank contents derived from a process knowledge model. Appendix B contains further sampling and analysis data from the March 1993 push mode core sampling event and data from the grab sampling event in August 1994 and May 1996 vapor flammability measurement. Of the two push mode cores taken in March of 1993, cores 55

  5. 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

  6. 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

  7. Appurtenance Influence on Type III Hanford Single-Shell Tank Structural Integrity

    SciTech Connect

    Sanborn, Scott E.; Larsen, Brian M.; Julyk, Larry J.; Johnson, Kenneth I.

    2012-02-26

    The interim stabilized Hanford Single Shell Tanks (SSTs) are currently undergoing a state of the art analysis to assess the structural integrity of the waste storage tanks, for cleanup and closure operations, considering their adverse thermal histories and an updated seismic hazard for the Hanford Site near Richland, Washington. The SSTs contain a variety of ancillary pits, piping, piping supports, risers, equipment, and penetrations known as appurtenances. These appurtenances may alter the structural response and ultimately could affect the structural integrity of the SSTs. An important challenge to the structural analysis of the SSTs is determining the impact of these appurtenances on structural integrity. To achieve this, the various appurtenances were reviewed and bounding appurtenance configurations for SST Types II and III tank designs were analyzed using finite element software. The bounding configurations for the Type II tanks considered four heavy offset pits with a central pit with and without a 36-inch diameter central post-construction penetration and four 42-inch diameter offset penetrations. The bounding configuration for the Type III tanks is a tank with two heavy offset pits and one heavy central pit. For each bounding configuration two finite element models are developed: a seismic analysis model and a thermal and operating loads analysis (TOLA) model. The TOLA models include a Type II or III thermal history, concrete cracking and thermal degradation, reinforcement yielding, and soil plasticity. Additionally, operating loads such as internal waste pressure and concentrated and distributed soil surface loads are applied to the TOLA model. The seismic model treats the tank concrete as linear elastic based on the present day degraded concrete properties. Also, in the seismic model the soil is treated as linear elastic while special techniques are used in the soil above the tank dome and along the tank wall to avoid soil arching and achieve the proper

  8. Identification of single-shell tank in-tank hardware obstructions to retrieval at Hanford Site Tank Farms

    SciTech Connect

    Ballou, R.A.

    1994-10-01

    Two retrieval technologies, one of which uses robot-deployed end effectors, will be demonstrated on the first single-shell tank (SST) waste to be retrieved at the Hanford Site. A significant impediment to the success of this technology in completing the Hanford retrieval mission is the presence of unique tank contents called in-tank hardware (ITH). In-tank hardware includes installed and discarded equipment and various other materials introduced into the tank. This paper identifies those items of ITH that will most influence retrieval operations in the arm-based demonstration project and in follow-on tank operations within the SST farms.

  9. Combined plasma gas-phase synthesis and colloidal processing of InP/ZnS core/shell nanocrystals

    PubMed Central

    2011-01-01

    Indium phosphide nanocrystals (InP NCs) with diameters ranging from 2 to 5 nm were synthesized with a scalable, flow-through, nonthermal plasma process at a rate ranging from 10 to 40 mg/h. The NC size is controlled through the plasma operating parameters, with the residence time of the gas in the plasma region strongly influencing the NC size. The NC size distribution is narrow with the standard deviation being less than 20% of the mean NC size. Zinc sulfide (ZnS) shells were grown around the plasma-synthesized InP NCs in a liquid phase reaction. Photoluminescence with quantum yields as high as 15% were observed for the InP/ZnS core-shell NCs. PMID:21711589

  10. 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

  11. 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

  12. 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.

  13. Fabry-Perot Microcavity Modes in Single GaP/GaNP Core/Shell Nanowires.

    PubMed

    Dobrovolsky, Alexander; Stehr, Jan E; Sukrittanon, Supanee; Kuang, Yanjin; Tu, Charles W; Chen, Weimin M; Buyanova, Irina A

    2015-12-16

    Semiconductor nanowires (NWs) are attracting increasing interest as nanobuilding blocks for optoelectronics and photonics. A novel material system that is highly suitable for these applications are GaNP NWs. In this article, we show that individual GaP/GaNP core/shell nanowires (NWs) grown by molecular beam epitaxy on Si substrates can act as Fabry-Perot (FP) microcavities. This conclusion is based on results of microphotoluminescence (μ-PL) measurements performed on individual NWs, which reveal periodic undulations of the PL intensity that follow an expected pattern of FP cavity modes. The cavity is concluded to be formed along the NW axis with the end facets acting as reflecting mirrors. The formation of the FP modes is shown to be facilitated by an increasing index contrast with the surrounding media. Spectral dependence of the group refractive index is also determined for the studied NWs. The observation of the FP microcavity modes in the GaP/GaNP core/shell NWs can be considered as a first step toward achieving lasing in this quasidirect bandgap semiconductor in the NW geometry.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

    Vernieres, Jerome; Benelmekki, Maria; Kim, Jeong-Hwan; Grammatikopoulos, Panagiotis; Bobo, Jean-François; Diaz, Rosa E.; 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 (DO3 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Single wound produced by simultaneous discharge of both shells from a double-barrel shotgun.

    PubMed

    Medich, M G; Cohle, S D; Burritt, M; Davison, P

    1990-03-01

    We present the case of a man who was killed by simultaneous discharge of both barrels of a double-barrel shotgun. Externally, there was a single wound simulating a wound made by a discharge of a single barrel. Test-firing of the shotgun against cloth, paper, and naugahyde targets revealed defects similar in shape to the wound in the victim. Simultaneous discharge of both barrels from a double-barrel shotgun may simulate the wound made by discharge of a single barrel.

  1. Maple procedures for the coupling of angular momenta. VIII. Spin-angular coefficients for single-shell configurations

    NASA Astrophysics Data System (ADS)

    Gaigalas, G.; Scharf, O.; Fritzsche, S.

    2005-03-01

    fast and reliable access to its standard quantities. Apart from various coefficients of fractional parentage and the reduced matrix elements of the unit tensors, these quantities include the so-called spin-angular coefficients, i.e. the spin-angular parts of the many-electron matrix elements of physical operators, taken in respect of a basis of symmetry-adapted subshell and configuration state functions. Method of solution: The concepts of quasispin and second quantized (creation and annihilation) operators in a spherical tensorial form are used to evaluate and calculate the spin-angular coefficients of one- and two-particle physical operators [G. Gaigalas, Lithuanian J. Phys. 39 (1999) 79, http://arXiv.org/physics/0405078; G. Gaigalas, Z. Rudzikas, C. Froese Fischer, J. Phys. B: At. Mol. Phys. 30 (1997) 3747]. Moreover, the same concepts are applied to support the computation of the coefficients of fractional grandparentage, i.e. the simultaneous de-coupling of two electrons from a single-shell configuration. All these coefficients are now implemented consistently within the framework of the RACAH program [S. Fritzsche, Comput. Phys. Comm. 103 (1997) 51; G. Gaigalas, S. Fritzsche, B. Fricke, Comput. Phys. Comm. 135 (2001) 219]. Restrictions on the complexity of the problem: In the present version of the RACAH program, all spin-angular coefficients are restricted to the case of a single open shell. For the symmetry-adapted subshell states of such single-shell configurations, the spin-angular coefficients can be calculated for (tensorial coupled) one-particle operators of arbitrary rank as well as for scalar two-particle operators. As previously [S. Fritzsche, Comput. Phys. Comm. 103 (1997) 51; G. Gaigalas, S. Fritzsche, B. Fricke, Comput. Phys. Comm. 135 (2001) 219], the RACAH program supports all atomic shells with l⩽3 in LS-coupling (i.e. s-, p-, d- and f-shells) and all subshells with j⩽9/2 in jj-coupling, respectively. Unusual features of the program: From the

  2. 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.

  3. 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.

  4. Characterization of solids in residual wastes from single-shell tanks at the Hanford site, Washington, USA.

    SciTech Connect

    Krupka, K. M.; Cantrell, K. J.; Todd Schaef, H.; Arey, B. W.; Heald, S. M.; Deutsch, W. J.; Lindberg, M. J.

    2010-03-01

    Solid phase physical and chemical characterization methods have been used in an ongoing study of residual wastes from several single-shell underground waste tanks at the U.S. Department of Energy's Hanford Site in southeastern Washington State. Because these wastes are highly-radioactive dispersible powders and are chemically-complex assemblages of crystalline and amorphous solids that contain contaminants as discrete phases and/or co-precipitated within oxide phases, their detailed characterization offers an extraordinary technical challenge. X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS) are the two principal methods used, along with a limited series of analyses by synchrotron-based methods, to characterize solid phases and their contaminant associations in these wastes.

  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. Status Report: Pretreatment chemistry evaluation-Wash and leach factors for the single-shell tank waste inventory

    SciTech Connect

    Colton, N.G.

    1996-09-01

    This report discusses a methodology developed to depict overall wash and leach factors for the Hanford single-shell tank (SST) inventory. The factors derived from this methodology, which is based on available partitioning data, are applicable to a composite SST inventory rather than only an assumed insoluble portion. The purpose of considering the entire inventory is to provide a more representative picture of the partitioning behavior of the analytes during envisioned waste retrieval and processing activities. The work described in this report was conducted by the Pretreatment Chemistry Evaluation task of the Tank Waste Remediation System (TWRS). The leach factors will be used to estimate the further removal of analytes, such as sodium, aluminum, phosphate, and other minor components. Wash and leach factors are given for elements expected to drive the volume of material disposed of as high-level waste (HLW).

  7. 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.

  8. 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).

  9. 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.

  10. Photothermal Imaging and Measurement of Protein Shell Stoichiometry of Single HIV-1 Gag Virus-Like Nanoparticles

    PubMed Central

    Vieweger, Mario; Goicochea, Nancy; Koh, Eun Sohl; Dragnea, Bogdan

    2011-01-01

    Virus life stages often constitute a complex chain of events, difficult to track in-vivo and in real-time. Challenges are associated with spatial and time limitations of current probes: most viruses are smaller than the diffraction limit of optical microscopes while the entire time-scale of virus dynamics spans over 8 orders of magnitude. Thus, virus processes such as entry, disassembly, and egress have generally remained poorly understood. Here we discuss photothermal heterodyne imaging (PHI) as a possible alternative to fluorescence microscopy in the study of single virus-like nanoparticle (VNP) dynamics, with relevance in particular to virus uncoating. Being based on optical absorption rather than emission, PHI could potentially surpass some of the current limitations associated with fluorescent labels. As proof-of-principle, single VNPs self-assembled from 60 nm DNA-functionalized gold nanoparticles (DNA-Au NPs) encapsulated in a Gag protein shell of the Human immunodeficiency virus (HIV-1) were imaged and their photothermal response compared with DNA-Au NPs. For the first-time, the protein stoichiometry of a single virus-like particle was estimated by a method other than electron microscopy. PMID:21854038

  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. 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.

  13. The effect of fe-dopant concentration on ethanol gas sensing properties of fe doped ZnO/ZnO shell/core nanorods

    NASA Astrophysics Data System (ADS)

    Khayatian, A.; Safa, S.; Azimirad, R.; Kashi, M. Almasi; Akhtarianfar, S. F.

    2016-10-01

    In this paper, Fe-doped ZnO/ZnO shell/core nanostructures were synthesized through a simple two-step method and the effects of Fe dopant concentrations (between 0 and 9 at%) on the structural, optical, electrical and gas sensing properties were investigated. The X-ray diffraction analysis revealed that all of the samples are crystallized in the same wurtzite hexagonal crystal structure with (002) peak as the main orientation. Nevertheless, the morphology of shell/core nanorods remained stable with increasing of Fe dopant, but the crystallinity improved. The ultraviolet-visible spectroscopy analysis showed that the Fe ions have coordination number of 3+ in the ZnO shell layer. The participation of Fe3+ ions into ZnO layer was also confirmed by Current-Voltage (I-V) curves where the resistance of nanorods was reduced with Fe concentration. Moreover, the ethanol-sensing properties of the Fe-doped ZnO/ZnO shell/core nanorod sensors were systematically investigated. According to the results, optimum gas sensing was obtained by the addition of 0.5 at% Fe to ZnO shell layer which lead to significant enhancement in ethanol gas response.

  14. A high-resolution infrared spectrum of IRC +10216. [carbon star immersed in expanding gas/dust shell

    NASA Technical Reports Server (NTRS)

    Barnes, T. G.; Hinkle, K. H.; Lambert, D. L.; Beer, R.

    1977-01-01

    The IR-emitting core and shell of IRC +10216 are investigated using a high-resolution spectrum covering the wavelength interval between 3 and 5 microns. Line identifications made or confirmed include those due to (C-12)(O-16), (C-13)(O-16), (C-12)(O-17), and (C-12)(O-18). A mean heliocentric velocity of about -32 km/s is obtained from the 42 least blended (C-12)O and (C-13)O lines, and the following isotopic abundance ratios are derived by comparing equivalent widths of the observed lines: C-12/C-13, C-12/C-14, O-16/O-17, and O-17/O-18. The structure of the expanding gas shell is examined, an explanation is offered for the lack of P Cygni profiles in the spectrum, and an unsuccessful search for other molecules is briefly discussed. It is concluded that a low C-12/C-13 ratio is not necessarily a signature of a carbon star.

  15. 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.

  16. 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.

  17. New polymer target-shell properties and characterizations. Appendix A

    SciTech Connect

    Honig, A.; Wei, X.; Fan, Q.; Alexander, N.; Palmer, N.

    1993-12-31

    A method for characterizing ICF target shells is presented, based on measurement of the gas released from a single shell into a small volume. It utilizes cryogenic permeation systems developed in connection with our work on ICF targets containing nuclear spin-polarized deuterium. Permeation rates for polystyrene and parylene-coated-polystyrene shells are measured at temperatures from 350K down to 180K. Burst or implosion pressure can be determined over a full temperature range down to 20K. Shell temperature is calculated from its gas leakage rate, calibrated by permeation measurements over the temperature range. Lag of shell temperature compared with sample-chamber temperature during warming of the latter is attributed to the weakness of the thermal link provided by both radiative heat transfer and free molecular conduction with small accommodation coefficients for helium and deuterium gas at the structure to which the shell is conductively linked, or at the surface of a conductively isolated shell. Quantification of this lag can provide a measure of atomic scale roughness of the shell outer surface. Also presented are reversible pre-rupture leakage phenomena for polystyrene and parylene-coated-polystyrene shells.

  18. Single-dot spectroscopy of zinc-blende CdSe/CdS core/shell nanocrystals: nonblinking and correlation with ensemble measurements.

    PubMed

    Qin, Haiyan; Niu, Yuan; Meng, Renyang; Lin, Xing; Lai, Runchen; Fang, Wei; Peng, Xiaogang

    2014-01-01

    Here we report the first series of phase-pure zinc-blende CdSe/CdS core/shell quantum dots (QDs) with reproducibly controlled shell thickness (4-16 monolayers), which are nonblinking (≥95% 'on' time) in single-exciton regime for the entire series. These unique QDs possess well-controlled yet simple excited-state decay dynamics at both single-dot and ensemble levels, extremely small nonblinking volume threshold, if any, and unique 'on' and 'off' probability statistics. The outstanding optical properties of the QDs at the single-dot level were found to be correlated well with their ensemble properties. These small and bright nonblinking QDs offer promising technical application prospect in both single-dot and ensemble levels. The consistent and reproducible experimental results shed new light on the mechanisms of blinking of QDs.

  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. Excitation of the 4d shell in Sb, Te, and BaF2 with inelastic electron scattering: Collective or single particle?

    NASA Astrophysics Data System (ADS)

    Franck, Carl; Schnatterly, S. E.

    1982-06-01

    Simple models suggest that the momentum-transfer (q) dependence of inelastic electron scattering is sensitive to the difference between collective and single-particle behavior in atomic dynamics. We measured the energy centroid of the 4d continuum peak for 0shells: Sb, Te, and BaF2, and find that a single-particle description is favored.

  1. 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.

  2. Pulsed laser deposition of single-crystalline Cu7In3/CuIn0.8Ga0.2Se2 core/shell nanowires

    PubMed Central

    2014-01-01

    Single-crystalline Cu7In3/CuIn0.8Ga0.2Se2 (CI/CIGS) core/shell nanowires are fabricated by pulsed laser deposition with Ni nanoparticles as catalyst. The CI/CIGS core/shell nanowires are made up of single-crystalline CI cores surrounded by single-crystalline CIGS shells. The CI/CIGS nanowires are grown at a considerably low temperature (350°C ~ 450°C) by vapor-liquid-solid mode combined with vapor-solid mode. The distribution density of the nanowires increases with the increasing of the deposition duration, and the substrate temperature determines the lengths of the nanowires. The U-V absorption spectra of the CIGS thin films with and without the CI/CIGS core/shell nanowires demonstrate that the CI/CIGS nanowires can remarkably enhance the absorption of CIGS thin films in the spectrum range of 300 to 900 nm. PACS 61.46. + w; 61.41.e; 81.15.Fg; 81.07.b PMID:25520597

  3. Pulsed laser deposition of single-crystalline Cu7In3/CuIn0.8Ga0.2Se2 core/shell nanowires

    NASA Astrophysics Data System (ADS)

    Zhao, Yu; Li, Hui; Zhu, Yan-Yan; Guan, Lei-Lei; Li, Yan-Li; Sun, Jian; Ying, Zhi-Feng; Wu, Jia-Da; Xu, Ning

    2014-12-01

    Single-crystalline Cu7In3/CuIn0.8Ga0.2Se2 (CI/CIGS) core/shell nanowires are fabricated by pulsed laser deposition with Ni nanoparticles as catalyst. The CI/CIGS core/shell nanowires are made up of single-crystalline CI cores surrounded by single-crystalline CIGS shells. The CI/CIGS nanowires are grown at a considerably low temperature (350°C ~ 450°C) by vapor-liquid-solid mode combined with vapor-solid mode. The distribution density of the nanowires increases with the increasing of the deposition duration, and the substrate temperature determines the lengths of the nanowires. The U-V absorption spectra of the CIGS thin films with and without the CI/CIGS core/shell nanowires demonstrate that the CI/CIGS nanowires can remarkably enhance the absorption of CIGS thin films in the spectrum range of 300 to 900 nm.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

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

    SciTech Connect

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

    2015-02-21

    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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Physical properties of gas disks around shell stars with and without dust

    NASA Technical Reports Server (NTRS)

    Grady, Carol A.

    1992-01-01

    Analysis of archival IRAS and IUE data has resulted in: (1) identification of 8 new A star proto-planetary candidates; (2) detection of a mass outflow event around Beta Pic (subsequently confirmed by the 1991 July HST observation); and (3) confirmation of the suggestion by Waters et al. (1988) that 51 Oph is a protoplanetary system similar to beta Pic with the detection of high density, high velocity, collisionally ionized accreting gas in the line of sight toward this star.

  16. Development and use of a two-dimensional interferometer to measure mass flow from a multi-shell Z-pinch gas puff.

    PubMed

    Coleman, P L; Lamppa, D C; Madden, R E; Wilson-Elliott, K; Jones, B; Ampleford, D J; Bliss, D E; Jennings, C; Bixler, A; Krishnan, M

    2012-08-01

    For gas puff Z-pinches, the K-shell x-ray yield is maximized with the use of a multi-shell nozzle. Optimization of the yield, verification of hydrodynamic models of the nozzle flows, and plausible MHD code modeling of the implosions require data on the radial and axial (R,Z) distribution of mass in the nozzle's flow field. Interferometry is a well-established technique for acquiring such data. We describe the development and use of a two-dimensional interferometer with emphasis on the required data reduction methods. We also show that the instrument can derive the flow from each individual nozzle in a multi-shell system.

  17. Rapid synthesis and characterization of hybrid ZnO@Au core-shell nanorods for high performance, low temperature NO2 gas sensor applications

    NASA Astrophysics Data System (ADS)

    Ponnuvelu, Dinesh Veeran; Pullithadathil, Biji; Prasad, Arun K.; Dhara, Sandip; Ashok, Anuradha; Mohamed, Kamruddin; Tyagi, Ashok Kumar; Raj, Baldev

    2015-11-01

    A rapid synthesis route for hybrid ZnO@Au core-shell nanorods has been realized for ultrasensitive, trace-level NO2 gas sensor applications. ZnO nanorods and hybrid ZnO@Au core-shell nanorods are structurally analyzed using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Optical characterization using UV-visible (UV-vis), photoluminescence (PL) and Raman spectroscopies elucidate alteration in the percentage of defect and charge transport properties of ZnO@Au core-shell nanorods. The study reveals the accumulation of electrons at metal-semiconductor junctions leading to upward band bending for ZnO and thus favors direct electron transfer from ZnO to Au nanoclusters, which mitigates charge carrier recombination process. The operating temperature of ZnO@Au core-shell nanorods based sensor significantly decreased to 150 °C compared to alternate NO2 sensors (300 °C). Moreover, a linear sensor response in the range of 0.5-5 ppm of NO2 concentration was observed with a lowest detection limit of 500 ppb using conventional electrodes. The defects with deep level, observed in ZnO nanorods and hybrid ZnO@Au core-shell nanorods influences local electron density, which in-turn indirectly influence the gas sensing properties. The ZnO@Au core-shell nanorods based sensor exhibited good selectivity toward NO2 and was found to be very stable.

  18. 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.

  19. Non-parametric representation and prediction of single- and multi-shell diffusion-weighted MRI data using Gaussian processes

    PubMed Central

    Andersson, Jesper L.R.; Sotiropoulos, Stamatios N.

    2015-01-01

    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. PMID:26236030

  20. 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

  1. 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.

  2. 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.

  3. Borehole Data Package for Calendar Year 2000 - 2001 RCRA Wells at Single-Shell Tank Waste Management Area S-SX

    SciTech Connect

    Horton, Duane G.; Johnson, Vernon G.

    2001-08-15

    Six new resource conservation and Recovery Act (RCRA) groundwater monitoring wells were installed at the single-shell tank farm Waste Management Area S-SX in July 2000 through March 2001 in partial fulfillment of Tri-Party Agreement milestones M-24-00L and M-24-00M. This document describes the drilling, construction, sampling and analyses of samples from the wells.

  4. 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).

  5. 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

  6. Shell structure and phase relations in electronic properties of metal nanowires from an electron-gas model

    NASA Astrophysics Data System (ADS)

    Han, Yong; Liu, Da-Jiang

    2010-09-01

    The electronic and dynamic properties of metal nanowires are analyzed by using a minimal electron-gas model (EGM), in which the nanowire is treated as a close system with variable Fermi energy as a function of nanowire radius. We show that the planar surface energy and the curvature energy from the EGM are reasonably consistent with those from previous stabilized-jellium-model calculations, especially for metals with low electron densities. The EGM shell structure due to the fillings of quantum-well subbands is similar to that from the stabilized jellium model. The crossings between subbands and Fermi energy level for the metal nanowire correspond to cusps on the chemical-potential curve versus nanowire radius, but inflection points on the surface-free-energy curve versus the radius, as in the case of metal nanofilms. We also find an oscillatory variation in electron density versus radius at the nanowire center with a global oscillation period which approximately equals half Fermi wavelength. Wire string tension, average binding energy, and thermodynamic stability from the EGM are in good agreement with the data from previous first-principles density-functional theory calculations. We also compare our model with those from previous reported free-electron models, in which the nanowire is treated as an open system with a constant Fermi energy. We demonstrate that the fundamental thermodynamic properties depend sensitively on the way that the potential wall is constructed in the models.

  7. Design of Gas-phase Synthesis of Core-Shell Particles by Computational Fluid – Aerosol Dynamics

    PubMed Central

    Buesser, B.; Pratsinis, S.E.

    2013-01-01

    Core-shell particles preserve the bulk properties (e.g. magnetic, optical) of the core while its surface is modified by a shell material. Continuous aerosol coating of core TiO2 nanoparticles with nanothin silicon dioxide shells by jet injection of hexamethyldisiloxane precursor vapor downstream of titania particle formation is elucidated by combining computational fluid and aerosol dynamics. The effect of inlet coating vapor concentration and mixing intensity on product shell thickness distribution is presented. Rapid mixing of the core aerosol with the shell precursor vapor facilitates efficient synthesis of hermetically coated core-shell nanoparticles. The predicted extent of hermetic coating shells is compared to the measured photocatalytic oxidation of isopropanol by such particles as hermetic SiO2 shells prevent the photocatalytic activity of titania. Finally the performance of a simpler, plug-flow coating model is assessed by comparisons to the present detailed CFD model in terms of coating efficiency and silica average shell thickness and texture. PMID:23729817

  8. MIGRATION OF GAS-LIQUID INCLUSIONS IN KCl AND NaCl SINGLE CRYSTALS

    SciTech Connect

    Olander, Donald R.; Machiels, Albert J.; Muchowski, Eugen

    1980-08-01

    Natural salt deposits contain small brine inclusions which can be set into motion by a temperature gradient arising from storage of nuclear wastes in the salt. Inclusions totally filled with liquid move up the temperature gradient, but cavities which are filled partly with liquid and partly by an insoluble gas move in the opposite direction. The velocities of these gas-liquid inclusions are calculated from a model which includes: heat transport in the gas/liquid/solid composite medium; vapor transport of water in the gas bubble as the principal mechanism causing cavity motion; and the effect of molecular and thermal diffusion on transport of salt in the liquid phase. An analytical expression for the inclusion velocity is obtainable with certain simplifications, which include: approximating the cubical cavity in the solid as a spherical hole containing a central gas bubble and an annular shell of liquid; neglecting interface kinetics (i.e., slow dissolution and crystallization steps) and assuming the process to be diffusion-controlled and disregarding fluid motion generated by surface tension gradients at the gas/liquid interface. The theory predicts a change in the migration direction at a critical volume fraction gas in the cavity. For gas fractions greater than this critical value, the theory gives the velocities of migration down the temperature gradient which are in satisfactory agreement with available experimental data.

  9. 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.

  10. 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.; 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.

  11. Tunable dual-emitting shell-crosslinked nano-objects as single-component ratiometric pH-sensing materials†

    PubMed Central

    Lee, Nam S.; Sun, Guorong; Lin, Lily Yun; Neumann, William L.; Freskos, John N.; Karwa, Amolkumar; Shieh, Jeng J.; Dorshow, Richard B.

    2014-01-01

    Dual-emitting photonic nano-objects that can sense changes in the environmental pH are designed based on shell-crosslinked micelles assembled from amphiphilic block copolymers and crosslinked with pH-insensitive chromophores. The chromophoric crosslinkers are tetra-functionalized pyrazine molecules that bear a set of terminal aliphatic amine groups and a set of anilino amine groups, which demonstrate morphology-dependent reactivities towards the poly(acrylic acid) shell domain of the nano-objects. The extent to which the anilino amine groups react with the nano-object shell is shown to affect the hypsochromic shift (blue-shift). The ratio of fluorescence intensity at 496 nm over that of 560 nm is dependent upon the solution pH. We report, herein, observations on the pH-sensitive dual-emission photophysical properties of rod-shaped or spherical nano-objects, whose shell domains offer two distinct platforms for amidation reactions to occur—through formation of activated esters upon addition of carbodiimide or pre-installation of activated ester groups. We demonstrate that physical manipulations (changes in morphology or particle dimensions) or chemical manipulations of the crosslinking reaction (the order of installation of activated esters) lead to fine tuning of dual-emission over ca. 60 nm in a physiologically relevant pH range. Rod-shaped shell-crosslinked nanostructures with poly(p-hydroxystyrene) core show blue-shift as a function of increasing pH while spherical shell-crosslinked nanostructures with polystyrene core and poly(ethylene oxide) corona exhibit blue-shift as a function of decreasing pH. PMID:25506129

  12. 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

  13. Borehole Data Package for 1998 Wells Installed at Single-Shell Tank Waste Management Area TX-TY

    SciTech Connect

    DG Horton; FN Hodges

    1999-03-23

    Four new Resource Conservation and Recovery Act (RCRA) groundwater monitoring wells were installed at the single-shell tank farm Waste Management Area (WMA) TX-TY during August through November of 1998 in fi,dfillment of Tri-Party Agreement (Eoology 1996) milestone M-24-38. The wells are 299-W1O-26, 299-W14-13, 299-W14-14, and 299-W15-40. Well 299-W1O-26 is located outside the east fence of the TY tank farm and replaces downgradient well299-W1O-18; well 299-W14-13 is located along the east fence near the northeast corner of the TX tank f- and replaces downgradient well 299-W14-12; well 299-W14-14 is located outside the east fence in the south ha.lfof the TX tank fiirm and is anew downgradient well; and well 299-W15-40 is located on the west side of the TX tank farm and is anew upgradient well. The locations of all wells in the monitoring network are shown on Figure 1. The groundwater monitoring plan for WMA TX-TY (Caggiano and Goodwin 1991) describes the hydrogeology of the 200 West Area and WMA TX-TY. An Interim Change Notice to the groundwater monitoring plan provides justification for the new wells. The new wells were constructed to the speciii- cations and requirements described in Washington Administrative Code (WAC) 173-160 and WAC 173-303. This document compiles &fiormation on the drilling and construction, well development pump instal- latio~ groundwater sampling, and sediment testing applicable to wells 299-W1O-26, 299-W14-13, 299-W14-14, and 299-W15-40. Appendix A contains the geologist's log, the Well Construction Sum- mary Repo~ and Well Summary Sheet (as-built diagram); Appendix B contains results of laboratory analyses of particle size distribution, p~ conductivity, calcium carbonate conten~ major cation and anion concentrations from 1:1 water: sediment extracts, and moisture conten~ Appendix C contains geophysical logs; and Appendix D contains the analytical results from groundwater samples obtained during well construction. Aqutier tests (slug tests

  14. Implementation of Single-Shot Ellipsometry on Gas Gun Experiments

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    We have built and implemented a time-resolved ellipsometry diagnostic for dynamic testing at Sandia National Laboratories. This diagnostic measures refractive index of a sample under dynamic conditions with a time resolution of a few nanoseconds. We show and discuss results from our first dynamic experiments on a gas gun. Future work will study geophysical materials under relevant pressure-temperature conditions. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2015-0376 A.

  15. 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

    2012-09-01

    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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. Evaluation of heat sources and effect of dry out in single-shell tanks 241-SX-108 and 241-SX-114

    SciTech Connect

    Ogden, D.M., Westinghouse Hanford

    1996-12-16

    This report examines two tanks on the list of Single-Shell Tanks with high heat loads. This report assesses the maximum temperatures that might exist in the two tanks 241-SX-108 and 241-SX-114. In addition to assessing current conditions in the tanks, the effect of the drying out of the center of the tank on the maximum temperature in the waste and concrete was evaluated. A reassessment of the head loads was also done using more recent temperature and psychrometric data obtained from these two tanks.

  1. 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.

  2. Proposed pushered single shell capsule design for the investigation of mid/high Z mix on the NIF

    NASA Astrophysics Data System (ADS)

    Sacks, Ryan; Tipton, Robert; Graziani, Frank

    2016-05-01

    The CD Mix campaign has given a detailed explination of the mix mechanics in the current ignition capsule designs by investigating the relationship between material mixing, shell-fuel interfaces, and the change in thermonuclear yield given a deuterated layer in the capsule. Alternative ignition scenarios include the use of double shell designs that incorporate high-Z material in the capsule. Simulations are conducted on a proposed capsule platform using the ARES code on a scaled capsule design using a partially reduced glass capsule design. This allows for the inclusion of deuterium on the inner surface of the pusher layer similar to the CD mix experiments. The presence of silicon dioxide allows for the investigation of the influence of higher Z material on the mixing characteristics.

  3. Single well seismic imaging of a gas-filled hydrofracture

    SciTech Connect

    Daley, Thomas M.; Gritto, Roland; Majer, Ernest L.

    2003-08-19

    A single well seismic survey was conducted at the Lost Hills, Ca oil field in a monitoring well as part of a CO2 injection test. The source was a piezoelectric seismic source and the sensors were a string of hydrophones hanging below the source. The survey was processed using standard CMP reflection seismology techniques. A potential reflection event was observed and interpreted as being caused by a near vertical hydrofracture. The radial distance between the survey well and the hydrofracture is estimated from Kirchoff migration using a velocity model derived from cross well seismic tomography. The hydrofracture location imaged after migration agrees with the location of an existing hydrofracture.

  4. 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

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

    DOE PAGES

    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 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

  6. Gas-Phase Protein Inner-Shell Spectroscopy by Coupling an Ion Trap with a Soft X-ray Beamline.

    PubMed

    Milosavljević, Aleksandar R; Canon, Francis; Nicolas, Christophe; Miron, Catalin; Nahon, Laurent; Giuliani, Alexandre

    2012-05-01

    C, N, and O near-edge ion yield spectroscopy of 8+ selected electrosprayed cations of cytochrome c protein (12 kDa) has been performed by coupling a linear quadrupole ion trap with a soft X-ray beamline. The photoactivation tandem mass spectra were recorded as a function of the photon energy. Photoionization of the precursor, accompanied by CO2 loss, is the dominant relaxation process, showing high photoion stability following direct or resonant photoionization. The partial ion yields extracted from recorded mass spectra show significantly different behaviors for single and double ionization channels, which can be qualitatively explained by different Auger decay mechanisms. However, the single ionization spectra reveal characteristic structures when compared to existing near-edge X-ray absorption fine structure (NEXAFS) spectra from thin films of peptides and proteins. Therefore, the present experiment opens up new avenues for near-edge X-ray spectroscopy of macromolecules in the gas phase, overcoming the radiation damage issue or the environmental effects as due to the surface, intermolecular interactions, and solvent.

  7. Effect of supercritical water shell on cavitation bubble dynamics

    NASA Astrophysics Data System (ADS)

    Shao, Wei-Hang; Chen, Wei-Zhong

    2015-05-01

    Based on reported experimental data, a new model for single cavitation bubble dynamics is proposed considering a supercritical water (SCW) shell surrounding the bubble. Theoretical investigations show that the SCW shell apparently slows down the oscillation of the bubble and cools the gas temperature inside the collapsing bubble. Furthermore, the model is simplified to a Rayleigh-Plesset-like equation for a thin SCW shell. The dependence of the bubble dynamics on the thickness and density of the SCW shell is studied. The results show the bubble dynamics depends on the thickness but is insensitive to the density of the SCW shell. The thicker the SCW shell is, the smaller are the wall velocity and the gas temperature in the bubble. In the authors’ opinion, the SCW shell works as a buffering agent. In collapsing, it is compressed to absorb a good deal of the work transformed into the bubble internal energy during bubble collapse so that it weakens the bubble oscillations. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174145 and 11334005).

  8. 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.

  9. 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.

  10. Facile synthesis of core/shell ZnO/ZnS nanofibers by electrospinning and gas-phase sulfidation for biosensor applications.

    PubMed

    Baranowska-Korczyc, Anna; Sobczak, Kamil; Dłużewski, Piotr; Reszka, Anna; Kowalski, Bogdan J; Kłopotowski, Łukasz; Elbaum, Danek; Fronc, Krzysztof

    2015-10-01

    This study describes a new method of passivating ZnO nanofiber-based devices with a ZnS layer. This one-step process was carried out in H2S gas at room temperature, and resulted in the formation of core/shell ZnO/ZnS nanofibers. This study presents the structural, optical and electrical properties of ZnO/ZnS nanofibers formed by a 2 nm ZnS sphalerite crystal shell covering a 5 nm ZnO wurtzite crystal core. The passivation process prevented free carriers from capture by oxygen molecules and significantly reduced the impact of O2 on nanostructure conductivity. The conductivity of the nanofibers was increased by three orders of magnitude after the sulfidation, the photoresponse time was reduced from 1500 s to 30 s, and the cathodoluminescence intensity increased with the sulfidation time thanks to the removal of ZnO surface defects by passivation. The ZnO/ZnS nanofibers were stable in water for over 30 days, and in phosphate buffers of acidic, neutral and alkaline pH for over 3 days. The by-products of the passivation process did not affect the conductivity of the devices. The potential of ZnO/ZnS nanofibers for protein biosensing is demonstrated using biotin and streptavidin as a model system. The presented ZnS shell preparation method can facilitate the construction of future sensors and protects the ZnO surface from dissolving in a biological environment.

  11. 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

  12. 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

    2012-08-01

    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.

  13. 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

    2012-08-01

    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. PMID:22747235

  14. Effect of a single injection of adrenaline on shell ultrastructure in a series of eggs from domestic hens.

    PubMed

    Solomon, S E; Hughes, B O; Gilbert, A B

    1987-12-01

    1. Adrenaline (1 mg in 1 ml water) was administered subcutaneously to three hens to determine whether any changes in the shell ultrastructure of subsequent eggs would occur. 2. The egg shells were examined in a scanning electron microscope after plasma etching. 3. The first three eggs laid by each bird after adrenaline injection were compared with previously-collected normal eggs from the same birds and also with control eggs collected over the same period from three hens which had received no adrenaline. 4. The first egg laid following adrenaline treatment was essentially normal but both the second and third eggs showed severe structural disorganisation at all levels, from the mamillary caps up to the cuticular layer. 5. Eggs laid 20 d or more after adrenaline treatment had reverted to normal. 6. The findings suggest that the abnormal eggs laid after hens have been exposed to disturbance or stress are likely to be affected in not only their external appearance but also to be of poor structural quality. PMID:3446329

  15. 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.

  16. 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

  17. 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. PMID:26332384

  18. Iridium single atom tips fabricated by field assisted reactive gas etching

    NASA Astrophysics Data System (ADS)

    Wood, John A.; Urban, Radovan; Salomons, Mark; Cloutier, Martin; Wolkow, Robert A.; Pitters, Jason L.

    2016-03-01

    We present a simple, reliable method to fabricate Ir single atom tips (SATs) from polycrystalline wire. An electrochemical etch in CaCl2 solution is followed by a field assisted reactive gas etch in vacuum at room temperature using oxygen as an etching gas and neon as an imaging gas. Once formed, SATs are cooled to liquid nitrogen temperatures and their underlying structure is examined through evaporation of the apex atoms. Furthermore, a method is developed to repair Ir SATs at liquid nitrogen temperatures when apex atoms evaporate. This method may be used to fabricate Ir SAT ion sources.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. Tunable core-shell single-walled carbon nanotube-Cu2S networked nanocomposites as high-performance cathodes for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Meng, Xiangbo; Riha, Shannon C.; Libera, Joseph A.; Wu, Qingliu; Wang, Hsien-Hau; Martinson, Alex B. F.; Elam, Jeffrey W.

    2015-04-01

    In this study, nanoscale copper(I) sulfide (n-Cu2S) was deposited over networks of single-walled carbon nanotubes (SWCNTs) by atomic layer deposition (ALD). This synthetic route provides a high degree of control for tuning the materials properties. The resulting core-shell SWCNT-n-Cu2S composite structure ensures an intimate contact between the two components while maintaining a high porosity for efficient transport of charges. Indeed, electrochemical testing demonstrates that these nanocomposites are promising as cathodes in lithium-ion batteries (LIBs), exhibiting excellent stability over 200 discharge-charge cycles with a sustainable, high capacity of 260 mAh g-1 (92% of the theoretical value in terms of Cu2S) and >99% Coulombic efficiency. This work establishes a general strategy for developing high-performance nanoscale electrode materials.

  6. 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.

  7. 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.

  8. [Determination of trace Hg element in gas by CVAAS with single optical path].

    PubMed

    Wang, Shuai; Wang, Peng; Wang, Xi-He; Gao, Ji-Hui; Zhang, Zhi-Guo; Wu, Shao-Hua

    2009-08-01

    Since the anthropogenic emissions of mercury into environment were mostly entering the atmosphere through flue gas, continuous monitoring of mercury in the flue gas was significant for mercury emission control. A bench scale test rig was set up for the measurement of mercury through both wet chemical method and CVAAS (cold vapor atomic absorption spectrometry) with single optical path. The concentration of Hg in absorbent solution was determined by Hydra AA mercury analyzer. The concentration of Hg in gas was calculated in terms of wet chemical testing results, which showed a stable rate of permeation device. Hg atom absorption signal intensity was detected and analyzed in comparison with the test results of wet chemical methods according to Beer-Lambert law. Experimental data well agreed with the theory analysis, which indicated that the single optical path was suitable for the determination of trace Hg element in pure gas. Further research work should aim at the improvement of system adaptability and anti-jamming ability. To reduce the intensity fluctuation of mercury lamp, another spectral line could be detected simultaneously. Interference from surroundings, e.g. dust in gas or spot on the quartz surface, could be eliminated by optoelectronic coupling. PMID:19839353

  9. Facile synthesis of core/shell ZnO/ZnS nanofibers by electrospinning and gas-phase sulfidation for biosensor applications.

    PubMed

    Baranowska-Korczyc, Anna; Sobczak, Kamil; Dłużewski, Piotr; Reszka, Anna; Kowalski, Bogdan J; Kłopotowski, Łukasz; Elbaum, Danek; Fronc, Krzysztof

    2015-10-01

    This study describes a new method of passivating ZnO nanofiber-based devices with a ZnS layer. This one-step process was carried out in H2S gas at room temperature, and resulted in the formation of core/shell ZnO/ZnS nanofibers. This study presents the structural, optical and electrical properties of ZnO/ZnS nanofibers formed by a 2 nm ZnS sphalerite crystal shell covering a 5 nm ZnO wurtzite crystal core. The passivation process prevented free carriers from capture by oxygen molecules and significantly reduced the impact of O2 on nanostructure conductivity. The conductivity of the nanofibers was increased by three orders of magnitude after the sulfidation, the photoresponse time was reduced from 1500 s to 30 s, and the cathodoluminescence intensity increased with the sulfidation time thanks to the removal of ZnO surface defects by passivation. The ZnO/ZnS nanofibers were stable in water for over 30 days, and in phosphate buffers of acidic, neutral and alkaline pH for over 3 days. The by-products of the passivation process did not affect the conductivity of the devices. The potential of ZnO/ZnS nanofibers for protein biosensing is demonstrated using biotin and streptavidin as a model system. The presented ZnS shell preparation method can facilitate the construction of future sensors and protects the ZnO surface from dissolving in a biological environment. PMID:26313635

  10. Engineering bacterial microcompartment shells: chimeric shell proteins and chimeric carboxysome shells.

    PubMed

    Cai, Fei; Sutter, Markus; Bernstein, Susan L; Kinney, James N; Kerfeld, Cheryl A

    2015-04-17

    Bacterial microcompartments (BMCs) are self-assembling organelles composed entirely of protein. Depending on the enzymes they encapsulate, BMCs function in either inorganic carbon fixation (carboxysomes) or organic carbon utilization (metabolosomes). The hallmark feature of all BMCs is a selectively permeable shell formed by multiple paralogous proteins, each proposed to confer specific flux characteristics. Gene clusters encoding diverse BMCs are distributed broadly across bacterial phyla, providing a rich variety of building blocks with a predicted range of permeability properties. In theory, shell permeability can be engineered by modifying residues flanking the pores (symmetry axes) of hexameric shell proteins or by combining shell proteins from different types of BMCs into chimeric shells. We undertook both approaches to altering shell properties using the carboxysome as a model system. There are two types of carboxysomes, α and β. In both, the predominant shell protein(s) contain a single copy of the BMC domain (pfam00936), but they are significantly different in primary structure. Indeed, phylogenetic analysis shows that the two types of carboxysome shell proteins are more similar to their counterparts in metabolosomes than to each other. We solved high resolution crystal structures of the major shell proteins, CsoS1 and CcmK2, and the presumed minor shell protein CcmK4, representing both types of cyanobacterial carboxysomes and then tested the interchangeability. The in vivo study presented here confirms that both engineering pores to mimic those of other shell proteins and the construction of chimeric shells is feasible.

  11. Effects of carrier gas dynamics on single wall carbon nanotube chiral distributions during laser vaporization synthesis.

    PubMed

    Landi, Brian J; Raffaelle, Ryne P

    2007-03-01

    We report on the utility of modifying the carrier gas dynamics during laser vaporization synthesis to alter the single wall carbon nanotube (SWNT) chiral distribution. SWNTs produced from an Alexandrite laser using conventional Ni/Co catalysts demonstrate marked differences in chiral distributions due to effects of helium gas and reactor chamber pressure, in comparison to conventional subambient pressures and argon gas. Optical absorption and Raman spectroscopies confirm that the SWNT diameter distribution decreases under higher pressure and with helium gas as opposed to argon. Fluorescence mapping of the raw soots in sodium dodecylbenzene sulfonate (SDBS)-D2O was used to estimate the relative (n, m)-SWNT content of the semiconducting types. A predominance of type II structures for each synthesis condition was observed. The distribution of SWNT chiral angles was observed to shift away from near-armchair configurations under higher pressure and with helium gas. These results illustrate the importance of gas type and pressure on the condensation/cooling rate, which allows for synthesis of specific SWNT chiral distributions.

  12. Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study.

    PubMed

    Romero-Hermida, M I; Romero-Enrique, J M; Morales-Flórez, V; Esquivias, L

    2016-08-21

    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. PMID:27544117

  13. 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.

  14. 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

    2014-01-01

    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%. PMID:24717635

  15. 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.

  16. Effect of plasma treatment on the gas sensor with single-walled carbon nanotube paste.

    PubMed

    Dong, Ki-Young; Ham, Dae-Jin; Kang, Byung Hyun; Lee, Keunsoo; Choi, Jinnil; Lee, Jin-Woo; Choi, Hyang Hee; Ju, Byeong-Kwon

    2012-01-30

    The effect of plasma treatment on the gas sensing properties of screen-printed single-walled carbon nanotube (SWCNT) pastes is reported. The gas sensors, using SWCNT pastes as a sensing material, were fabricated by photolithography and screen printing. The SWCNT pastes were deposited between interdigitated electrodes on heater membrane by screen printing. In order to functionalize the pastes, they were plasma treated using several gases which produce defects caused by reactive ion etching. The Ar and O(2) plasma-treated SWCNT pastes exhibited a large response to NO(2) exposure and the fluorinated gas, such as CF(4) and SF(6), plasma-treated SWCNT pastes exhibited a large response to NH(3) exposure. PMID:22284456

  17. Atomic layer deposition on suspended single-walled carbon nanotubes via gas-phase noncovalent functionalization.

    PubMed

    Farmer, Damon B; Gordon, Roy G

    2006-04-01

    Alternating exposures of nitrogen dioxide gas and trimethylaluminum vapor are shown to functionalize the surfaces of single-walled carbon nanotubes with a self-limited monolayer. Functionalized nanotube surfaces are susceptible to atomic layer deposition of continuous, radially isotropic material. This allows for the creation of coaxial nanotube structures of multiple materials with precisely controlled diameters. Functionalization involves only weak physical bonding, avoiding covalent modification, which should preserve the unique optical, electrical, and mechanical properties of the nanotubes. PMID:16608267

  18. Method of calculating gas dynamics and heat transfer in single stage refrigeration units

    NASA Technical Reports Server (NTRS)

    Zhitomirskiy, I. S.; Popolskiy, A. B.

    1974-01-01

    A generalized mathematical model of gas-dynamic and heat transfer processes in single-stage regenerative installations operating in Stirling, MacMahon, Gifford-MacMahon, and pulsating tube cycles is proposed. A numerical method os solving initial equations on a digital computer is given. This makes it possible to calculate the change in the thermodynamic parameters in the working cycle in different machine components, as well as the dependence of cold productivity on the temperature level in the steady regime.

  19. Radioactive air emissions notice of construction use of a portable exhauster on single-shell tanks during salt well pumping

    SciTech Connect

    HOMAN, N.A.

    1999-07-14

    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 singleshell tanks (SSTs) during salt well pumping. Table 1-1 lists SSTs covered by this NOC. This GOC 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. The primary objective of providing active ventilation to these SSTs during salt well pumping is to reduce the risk of postulated accidents to remain within risk guidelines. It is anticipated that salt well pumping will release gases entrapped within the waste as the liquid level is lowered, because of less hydrostatic force keeping the gases in place. Hanford Site waste tanks must comply with the Tank Farms authorization basis (DESH 1997) that requires that the flammable gas concentration be less than 25 percent of the lower flammability limit

  20. Albuminated Glycoenzymes: Enzyme Stabilization through Orthogonal Attachment of a Single-Layered Protein Shell around a Central Glycoenzyme Core.

    PubMed

    Ritter, Dustin W; Newton, Jared M; Roberts, Jason R; McShane, Michael J

    2016-05-18

    Here we demonstrate an approach to stabilize enzymes through the orthogonal covalent attachment of albumin on the single-enzyme level. Albuminated glycoenzymes (AGs) based upon glucose oxidase and catalase from Aspergillus niger were prepared in this manner. Gel filtration chromatography and dynamic light scattering support modification, with an increase in hydrodynamic radius of ca. 60% upon albumination. Both AGs demonstrate a marked resistance to aggregation during heating to 90 °C, but this effect is more profound in albuminated catalase. The functional characteristics of albuminated glucose oxidase vary considerably with exposure type. The AG's thermal inactivation is reduced more than 25 times compared to native glucose oxidase, and moderate stabilization is observed with one month storage at 37 °C. However, albumination has no effect on operational stability of glucose oxidase.

  1. Data Package for Calendar Year 2002 RCRA Groundwater Monitoring Wells at Single-Shell Tank Waste Management Area TX-TY

    SciTech Connect

    Horton, Duane G.

    2003-04-15

    Two new RCRA groundwater monitoring wells were installed at the single-shell tank farm at Waste Management Area TX-TY in October and November 2002. This document provides the information on drilling and construction of these wells. Two new Resource Conservation and Recovery Act (RCRA) groundwater monitoring wells were installed at the single-shell tank farm Waste Management Area (WMA) TX-TY in October and November 2002 in fulfillment of Tri-Party Agreement (Ecology et al. 1998) Milestone M-24-00N. The well names are 299-W14-19 and 299-W15-44; the corresponding well numbers are C3957 and C3956, respectively. Well 299-W14-19 is located east of the central part of the TX Tank Farm and is a downgradient well filling a gap in the monitoring network between wells 299-W14-14 and 299-W14-6. Well 299-W15-44 is located at the southwest corner of the TX Tank Farm in an area where groundwater flow has been artificially altered toward the southwest by the 200-ZP-1 Operable Unit pump-and-treat system. The well is in the cone of depression of the 200-ZP-1 extraction wells and is downgradient of WMA TX-TY. The locations of all wells in the WMA TX-TY monitoring network are shown on Figure 1. The original assessment monitoring plan for WMA TX-TY was issued in 1993 (Caggiano and Chou 1993). That plan was updated for the continued assessment at WMA TX-TY in 2001 (Hodges and Chou 2001). The updated 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, the updated assessment plan for WMA TX-TY (Hodges and Chou 2001), and the description of work for well drilling and construction. This document compiles information on the drilling and construction, geophysical logging, and sediment and groundwater sampling applicable to the installation of wells 299-W14-19 and 299-W15-44. The information on drilling and construction, well development, and pump

  2. 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.

  3. MVC Shell

    2008-06-03

    Provides the shell of a plugin based application environment that builds on MVC Framework to allow one to rapidly construct an application by using a collection of plugins. The MVC Shell is implemented in C# as a .NET 2.0 application that can then be used as a shell for building a plugin based application. The infrastructure allows for dynamically processing a specified collection of plugins in order to determine the functionality of the application, wheremore » all plugins operate within the context of the underlying MVC Framework environment.« less

  4. Structural analysis of Hanford`s single-shell 241-C-106 tank: A first step toward waste-tank remediation

    SciTech Connect

    Harris, J.P.; Julyk, L.J.; Marlow, R.S.; Moore, C.J.; Day, J.P.; Dyrness, A.D.; Jagadish, P.; Shulman, J.S.

    1993-10-01

    The buried single-shell waste tank 241-C-106, located at the US Department of Energy`s Hanford Site, has been a repository for various liquid radioactive waste materials since its construction in 1943. A first step toward waste tank remediation is demonstrating that remediation activities can be performed safely. Determination of the current structural capacity of this high-heat tank is an important element in this assessment. A structural finite-element model of tank 241-C-106 has been developed to assess the tank`s structural integrity with respect to in situ conditions and additional remediation surface loads. To predict structural integrity realistically, the model appropriately addresses two complex issues: (1) surrounding soil-tank interaction associated with thermal expansion cycling and surcharge load distribution and (2) concrete-property degradation and creep resulting from exposure to high temperatures generated by the waste. This paper describes the development of the 241-C-106 structural model, analysis methodology, and tank-specific structural acceptance criteria.

  5. 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.

  6. Borehole Data Package for RCRA Well 299-W22-47 at Single-Shell Tank Waste Management Area S-SX, Hanford Site, Washington

    SciTech Connect

    Horton, Duane G.; Chamness, Mickie A.

    2006-04-17

    One new Resource Conservation and Recovery Act (RCRA) groundwater assessment well was installed at single-shell tank Waste Management Area (WMA) S-SX in fiscal year (FY) 2005 to fulfill commitments for well installations proposed in Hanford Federal Facility Agreement and Consent Order, Milestone M-24-57 (2004). The need for the new well, well 299-W22-47, was identified during a data quality objectives process for establishing a RCRA/ Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)/Atomic Energy Act (AEA) integrated 200 West and 200 East Area Groundwater Monitoring Network. This document provides a compilation of all available geologic data, spectral gamma ray logs, hydrogeologic data and well information obtained during drilling, well construction, well development, pump installation, aquifer testing, and sample collection/analysis activities. Appendix A contains the Well Summary Sheets, the Well Construction Summary Report, the geologist's Borehole Log, well development and pump installation records, and well survey results. Appendix B contains analytical results from groundwater samples collected during drilling. Appendix C contains complete spectral gamma ray logs and borehole deviation surveys.

  7. Enhanced up/down-conversion luminescence and heat: Simultaneously achieving in one single core-shell structure for multimodal imaging guided therapy.

    PubMed

    He, Fei; Feng, Lili; Yang, Piaoping; Liu, Bin; Gai, Shili; Yang, Guixin; Dai, Yunlu; Lin, Jun

    2016-10-01

    Upon near-infrared (NIR) light irradiation, the Nd(3+) doping derived down-conversion luminescence (DCL) in NIR region and thermal effect are extremely fascinating in bio-imaging and photothermal therapy (PTT) fields. However, the concentration quenching induced opposite changing trend of the two properties makes it difficult to get desired DCL and thermal effect together in one single particle. In this study, we firstly designed a unique NaGdF4:0.3%Nd@NaGdF4@NaGdF4:10%Yb/1%Er@NaGdF4:10%Yb @NaNdF4:10%Yb multiple core-shell structure. Here the inert two layers (NaGdF4 and NaGdF4:10%Yb) can substantially eliminate the quenching effects, thus achieving markedly enhanced NIR-to-NIR DCL, NIR-to-Vis up-conversion luminescence (UCL), and thermal effect under a single 808 nm light excitation simultaneously. The UCL excites the attached photosensitive drug (Au25 nanoclusters) to generate singlet oxygen ((1)O2) for photodynamic therapy (PDT), while DCL with strong NIR emission serves as probe for sensitive deep-tissue imaging. The in vitro and in vivo experimental results demonstrate the excellent cancer inhibition efficacy of this platform due to a synergistic effect arising from the combined PTT and PDT. Furthermore, multimodal imaging including fluorescence imaging (FI), photothermal imaging (PTI), and photoacoustic imaging (PAI) has been obtained, which is used to monitor the drug delivery process, internal structure of tumor and photo-therapeutic process, thus achieving the target of imaging-guided cancer therapy. PMID:27512942

  8. Evaporation and heating of a single suspended coal-water slurry droplet in hot gas streams

    SciTech Connect

    Shi-chune, Y.; Liu, L.

    1982-01-01

    The evaporation, heating, and burning of single coal-water slurry droplets are studied. The coal selected in this study is Pittsburgh Seam number 8 coal which is a medium volatile caking bituminous coal. The droplet is suspended on a microthermocouple and exposed to a hot gas stream. Temperature measurement and microscopic observation are performed in the parametric studies. The duration of water evaporation in CWS droplets decreases with the reduction of the droplet size, increasing of coal weight fraction, and increasing of gas temperature and velocity. The duration of heat-up is always significant due to the agglomeration. The CWS droplets are generally observed to swell like popcorn during heating. A model for the formation of the popped swelling is proposed and discussed.

  9. Electrical properties of gas sensors based on graphene and single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kondrashov, Ivan I.; Sokolov, Igor V.; Rusakov, Pavel S.; Rybin, Maxim G.; Barmin, Alexander A.; Rizakhanov, Razhudin N.; Obraztsova, Elena D.

    2016-01-01

    Here, we present investigation of the influence of different gases (carbon dioxide, ammonia, and iodine vapor) on the sensory properties of graphene and single-wall carbon nanotube films. The gas molecules are adsorbed by carbon films (graphene or nanotubes) and change the film's electrical resistance. In the course of this work, the setup for studying the electrophysical properties of carbon nanomaterials has been designed and constructed in the lab. With this home-made equipment, we have demonstrated a high efficiency of graphene and nanotubes as adsorbents of different gases and a possibility to use these materials as gas sensors. We have also performed a chemical modification of graphene and carbon nanotubes by attaching the nanoparticles of calcium carbonate (CaCO3) to improve the sensitivity and selectivity of sensors.

  10. NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography.

    PubMed

    Hong, Li-Yang; Lin, Heh-Nan

    2016-01-01

    In this work, the fabrication of single titanium oxide nanodot (ND) resistive sensors for NO gas sensing at room temperature is reported. Two atomic force microscopy nanolithography methods, nanomachining and nano-oxidation, are employed. A single titanium nanowire (NW) is created first along with contact electrodes and a single titanium oxide ND is subsequently produced in the NW. Gas sensing is realized by the photo-activation and the photo-recovery approaches. It is found that a sensor with a smaller ND has better performance than a larger one. A response of 31%, a response time of 91 s, and a recovery time of 184 s have been achieved at a concentration of 10 ppm for a ND with a size of around 80 nm. The present work demonstrates the potential application of single metal oxide NDs for gas sensing with a performance that is comparable with that of metal oxide nanowire gas sensors. PMID:27547622

  11. NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography

    PubMed Central

    Hong, Li-Yang

    2016-01-01

    Summary In this work, the fabrication of single titanium oxide nanodot (ND) resistive sensors for NO gas sensing at room temperature is reported. Two atomic force microscopy nanolithography methods, nanomachining and nano-oxidation, are employed. A single titanium nanowire (NW) is created first along with contact electrodes and a single titanium oxide ND is subsequently produced in the NW. Gas sensing is realized by the photo-activation and the photo-recovery approaches. It is found that a sensor with a smaller ND has better performance than a larger one. A response of 31%, a response time of 91 s, and a recovery time of 184 s have been achieved at a concentration of 10 ppm for a ND with a size of around 80 nm. The present work demonstrates the potential application of single metal oxide NDs for gas sensing with a performance that is comparable with that of metal oxide nanowire gas sensors. PMID:27547622

  12. 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. PMID:23811865

  13. Exciton gas compression and metallic condensation in a single semiconductor quantum wire.

    PubMed

    Alén, B; Fuster, D; Muñoz-Matutano, G; Martínez-Pastor, J; González, Y; Canet-Ferrer, J; González, L

    2008-08-01

    We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidence of metallic liquid condensation at low temperatures. First, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Second, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at n{c} approximately 1 x 10;{5} cm;{-1} and T{c} approximately 35 K, respectively.

  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. PMID:26433788

  15. 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.

  16. 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...

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Borehole data package for wells 299-E33-334 and 299-E33-335 at single-shell tank waste management Area B-BX-BY

    SciTech Connect

    DG Horton

    2000-06-01

    Two new Resource Conservation and Recovery Act (RCRA) groundwater monitoring wells were installed at the single-shell tank farm Waste Management Area (WMA) B-BX-BY during December 1999 through February 2000 in fulfillment of Tri-Party Agreement (Ecology 1996) Milestone M-24-45. The wells are 299-E33-334 and 299-E33-335. These wells were installed in support of the WMA B-BX-BY assessment to track the movement of contaminant plumes that appear to be entering the WMA from the northeast. Well 299-E33-334 is located outside the southwest comer of the 241-BX tank farm and well 299-E33-335 is located south of the 241-BX tank farm. The locations of all wells in the extended monitoring network for WMA B-BX-BY are shown in a figure. The new wells were constructed to the specifications and requirements described in Washington Administrative Code (WAC) 173-160 and WAC 173-303, in the assessment groundwater monitoring plan (Narbutovskih 2000), and in the description of work for well drilling and installation. This document compiles information on the drilling, construction, well development, pump installation, and sampling activities applicable to wells 299-E33-334 and 299-E33-335. Appendix A contains copies of the Well Summary Sheets (as-built diagrams), the Well Construction Summary Reports, and the geologist's logs. Appendix B contains results of laboratory analyses of moisture content on samples from 299-E33-334 (moisture data were not collected from well 299-E33-335). Appendix C contains borehole geophysical logs and Appendix D contains analytical results from groundwater samples obtained during well construction. Additional documentation concerning well construction is on file with Bechtel Hanford, Inc.

  2. 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.

  3. The detection of single electrons using a Micromegas gas amplification and a MediPix2 CMOS pixel readout

    NASA Astrophysics Data System (ADS)

    Fornaini, A.; Campbell, M.; Chefdeville, M.; Colas, P.; Colijn, A. P.; van der Graaf, H.; Giomataris, Y.; Heijne, E. H. M.; Kluit, P.; Llopart, X.; Schmitz, J.; Timmermans, J.; Visschers, J. L.

    2005-07-01

    By placing a Micromegas gas gain grid on top of a CMOS pixel readout circuit (MediPix2), we developed a device which acts as a pixel-segmented direct anode in gas-filled detectors. With a He/Isobutane 80/20 mixture (capable of achieving gas gain factors up to 20×103) and employing a drift length of 15 mm, signals from radioactive sources and cosmic radiation were measured. Single primary electrons originating from the passage of cosmic muons through the gas volume were detected with an efficiency higher than 90%.

  4. Shell appraising deepwater discovery off Philippines

    SciTech Connect

    Scherer, M. ); Lambers, E.J.T.; Steffens, G.S. )

    1993-05-10

    Shell International Petroleum Co. Ltd. negotiated a farmout in 1990 from Occidental International Exploration and Production Co. for Block SC-38 in the South China Sea off Palawan, Philippines, following Oxy's discovery of gas in 1989 in a Miocene Nido limestone buildup. Under the terms of the farmout agreement, Shell became operator with a 50% share. Following the disappointing well North Iloc 1, Shell was successful in finding oil and gas in Malampaya 1. Water 700-1,000 m deep, remoteness, and adverse weather conditions have imposed major challenges for offshore operations. The paper describes the tectonic setting; the Nido limestone play; the Malampaya discovery; and Shell's appraisal studies.

  5. 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

  6. Single and double capture in F9+ + Ar collisions: Comparison of total capture with capture occurring from the Ar K shell

    NASA Astrophysics Data System (ADS)

    La Mantia, David; Kumara, Nuwan; Kayani, Asghar; Simon, Anna; Tanis, John

    2016-05-01

    Total cross sections for single and double capture, as well as the corresponding cross sections for capture resulting in the emission of an Ar K x ray, were measured. This work was performed at Western Michigan University with the use of the tandem Van de Graaff accelerator. A 45 MeV beam of fully-stripped fluorine ions was collided with argon gas molecules in a differentially pumped cell. Surface barrier detectors were used to observe the charge changed projectiles and a Si(Li) x-ray detector, placed at 90o to the incident beam, were used to measure coincidences with Ar K x rays. The total capture cross sections are compared to previously measured cross sections in the existing literature. The coincidence cross sections, considerably smaller than the total cross sections, are found to be nearly equal for single and double capture in contrast to the total cross sections, which vary by about an order of magnitude. Possible reasons for this behavior are discussed. Supported in part by the NSF.

  7. 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

  8. 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.

  9. Effect of Au nanorods on potential barrier modulation in morphologically controlled Au@Cu2O core-shell nanoreactors for gas sensor applications.

    PubMed

    Majhi, Sanjit Manohar; Rai, Prabhakar; Raj, Sudarsan; Chon, Bum-Soo; Park, Kyung-Kuen; Yu, Yeon-Tae

    2014-05-28

    In this work, Au@Cu2O core-shell nanoparticles (NPs) were synthesized by simple solution route and applied for CO sensing applications. Au@Cu2O core-shell NPs were formed by the deposition of 30-60 nm Cu2O shell layer on Au nanorods (NRs) having 10-15 nm width and 40-60 nm length. The morphology of Au@Cu2O core-shell NPs was tuned from brick to spherical shape by tuning the pH of the solution. In the absence of Au NRs, cubelike Cu2O NPs having ∼200 nm diameters were formed. The sensor having Au@Cu2O core-shell layer exhibited higher CO sensitivity compared to bare Cu2O NPs layer. Tuning of morphology of Au@Cu2O core-shell NPs from brick to spherical shape significantly lowered the air resistance. Transition from p- to n-type response was observed for all devices below 150 °C. It was demonstrated that performance of sensor depends not only on the electronic sensitization of Au NRs but also on the morphology of the Au@Cu2O core-shell NPs.

  10. 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…

  11. Large ultrathin shelled drops produced via non-confined microfluidics.

    PubMed

    Chaurasia, Ankur S; Josephides, Dimitris N; Sajjadi, Shahriar

    2015-02-01

    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.

  12. 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

  13. Detection of the Detached Dust Shell of U Antliae at Mid-infrared Wavelengths with AKARI/IRC

    NASA Astrophysics Data System (ADS)

    Arimatsu, Ko; Izumiura, Hideyuki; Ueta, Toshiya; Yamamura, Issei; Onaka, Takashi

    2011-03-01

    We report mid-infrared (MIR) imaging observations of the carbon star U Ant made with the Infrared Camera (IRC) on board AKARI. Subtraction of the artifacts and extended point-spread function of the central star reveals the detached dust shell around the carbon star at MIR wavelengths (15 and 24 μm) for the first time. The observed radial brightness profiles of the MIR emission are well explained by two shells at 43'' and 50'' from the central star detected in optical scattered light observations. Combining Herschel/PACS, AKARI/FIS, and AKARI/IRC data, we obtain the infrared spectral energy distribution (SED) of the thermal emission from the detached shell of U Ant in a wide infrared spectral range of 15-160 μm. Thermal emission of amorphous carbon grains with a single temperature cannot account for the observed SED from 15 to 160 μm: it underestimates the emission at 15 μm. Alternatively, the observed SED is fitted by the model in which amorphous carbon grains in the two shells have different temperatures of 60 and 104 K, which allocates most dust mass in the shell at 50''. This supports the previous suggestion that the 43'' shell is gas-rich and the 50'' shell is dust-rich. We suggest a possibility that the segregation of the gas and dust resulting from the drift motion of submicron-sized dust grains relative to the gas and that the hot dust component associated with the gas-rich shell is composed of very small grains that are strongly coupled with the gas.

  14. Functionalized single wall carbon nanotube sensor in a perturbed microwave resonant cavity based toxin/pollutant gas pressure sensor

    NASA Astrophysics Data System (ADS)

    Tooski, S. B.

    2010-02-01

    The Vlasov and Maxwell's equations are established and solved numerically to describe the effects of toxin/pollutant gas pressure and functionalized single wall carbon nanotube (SWCNT) sensor in a perturbed microwave resonant cavity. The dependence of the absorption coefficient on incident frequency, toxin/pollutant gas pressure, electron density, and collision frequency is presented. The numerical results illustrate that the resonant frequency shifts by a suitable amount for modest changes in toxin/pollutant gas pressure. It is also illustrated that high density and low collision of the blend of toxin/pollutant gas and SWCNT sensor in a microwave resonant cavity can be employed as broadband absorption of microwave and the detection of toxin/pollutant gas characteristics through adjustments of the amount of toxin/pollutant gas pressure and functionalized SCWNT sensor. The numerical results additionally illustrate that the microwave absorption spectra of the blend of toxin/pollutant gas and SWCNT sensor in a microwave resonant cavity are in good agreement with the available experimental data. The present method is, in principle, applicable to any kind of a single nanofiber, nanowire, silica gel, cotton fiber, and even various types of nanotubes.

  15. Multidimensional Analysis of Direct-Drive Plastic-Shell Implosions on OMEGA

    NASA Astrophysics Data System (ADS)

    Radha, P. B.

    2004-11-01

    Direct-drive implosions of plastic shells with the OMEGA laser are used as energy-scaled warm surrogates for ignition cryogenic targets designed for use on the National Ignition Facility. Plastic targets involve varying shell thickness (15 to 33 μm), fill pressures (3 to 15 atm), and shell adiabats. The multidimensional hydrodynamics code DRACO is used to evaluate the effects of capsule-surface roughness and illumination nonuniformities on target performance. These simulations indicate that shell stability during the acceleration phase plays a critical role in determining fusion yields. For shells that are thick enough to survive the Rayleigh--Taylor growth, target yields are significantly reduced by growth of the long (ℓ < 10) and intermediate modes (20 < ℓ < 50) occurring from single-beam laser nonuniformities. The neutron production rate for these thick shells truncates relative to one-dimensional (1-D) predictions. The neutron-rate curves for the thinner shells, however, have significantly lower amplitudes and widths closer to 1-D results, indicating shell breakup during the acceleration phase. The simulation results are consistent with experimental observations. Previously, the stability of plastic-shell implosions had been correlated to a static ``mix-width'' at the boundary of the gas and plastic pusher estimated using a variety of experimental observables and an assumption of spherical symmetry. Results of these 2-D simulations provide a comprehensive understanding of warm-target implosion dynamics without assumptions of spherical symmetry and serve to answer the question of the hydrodynamic surrogacy between these plastic-shell implosions and the cryogenic ignition designs.

  16. 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.

  17. Does Moisture Influence the Chemical Detection of Gas Molecules Adsorbed on Single-Wall Carbon Nanotubes?

    NASA Astrophysics Data System (ADS)

    Yu, Ming; Tian, W. Q.; Jayanthi, C. S.; Wu, S. Y.

    2009-03-01

    In this work, the role of water in the detection of hydrazine (N2H4) by a single-wall carbon nanotube (SWCNT) is investigated using first principles electronic structure calculations (DFT/GGA--USPP)[1]. This calculation is undertaken to interpret the experimental resistivity measurements for N2H4 adsorbed on SWCNT that reveal an n-type behavior [2]. Our preliminary theoretical studies of the adsorption of N2H4 on SWCNT revealed physisorption for N2H4 and an unaltered band structure for the SWCNT [3]. This prompted us to look into the role of water on the bonding of N2H4 to the SWCNT. We found that, by introducing a monolayer of water film on the (8,0) SWCNT, the adsorption of N2H4 can introduce occupied states near the Fermi level, exhibiting an n-type behavior. However, the introduction of just few water molecules was not sufficient to influence the electronic structure of N2H4/SWCNT. Presently, we are studying the influence of water films on the chemical detection of a variety of other gas molecules (N2, NH3, etc.) by SWCNTs, and the results from such studies will also be reported. [1]. G. Kresse et al. Phys. Rev. B 54, 11169 (1996). [2]. S. Desai, et al. (APS, March 2008). [3]. M. Yu, et al. (APS, March 2008).

  18. Controllable preparation of copper phthalocyanine single crystal nano column and its chlorine gas sensing properties

    NASA Astrophysics Data System (ADS)

    Zhao, Jianhong; Qiao, Zhenfang; Zhang, Yumin; Zou, Taoyu; Yu, Leiming; Luo, Li; Wang, Xiaoyan; Yang, Yiji; Wang, Hai; Tang, Libin

    2016-09-01

    The unsubstituted copper phthalocyanine (CuPc) single crystal nano columns were fabricated for the first time as chlorine (Cl2) gas sensors in this paper. The nano columns of CuPc have been prepared on different substrates via template-free physical vapor deposition (PVD) approach. The growth mechanism of CuPc nano column on quartz was explored and the same condition used on other substrates including glass, sapphire (C-plane<0001>, M-plane<10 1 ¯ 0 >, R-plane<1 1 ¯ 02 >), Si and SiO2/Si came to a same conclusion, which confirmed that the aligned growth of CuPc nano column is not substrate-dependent. And then the CuPc nano column with special morphology was integrated as in-situ sensor device which exhibits high sensitivity and selectivity towards Cl2 at room temperature with a minimum detection limit as low as 0.08 ppm. The response of sensor was found to increase linearly (26 ˜659 % ) with the increase for Cl2 within concentration range (0.08 ˜4.0 ppm ) . These results clearly demonstrate the great potential of the nano column growth and device integration approach for sensor device.

  19. A survey of tracer gas techniques for estimation airflow and effective volumes in single and multizone buildings

    SciTech Connect

    O'Neill, P.J.

    1990-10-01

    This paper briefly describes the development of tracer gas techniques. These techniques were introduced over 50 years ago and have evolved into a number of distinct methods. These methods are often tailored to a specific application or to obtain particular information about the flow and volume system. Single-zone techniques are utilized when the structure or zone is relatively well-mixed and can be characterized by a single concentration measurement. Areas or rooms within a single-family residence can sometimes be closely approximated as one well-mixed zone. Multizone techniques are required when the building is composed of two or more zones which communicate with one another through interzonal airflows. Commercial office buildings are usually multizone systems. This paper focuses on single and multiple gas tracer techniques. Traditionally, multizone systems have been analyzed by using a different tracer for each zone. These techniques require equipment capable of accurately injecting and detecting each of the tracers which can be cumbersome in large order systems. Recently, a number of methods have been proposed which use a single tracer gas to estimate flow and effective volumes in multizone systems. 24 refs., 2 figs., 1 tab.

  20. Detection of a CO and NH3 gas mixture using carboxylic acid-functionalized single-walled carbon nanotubes.

    PubMed

    Dong, Ki-Young; Choi, Jinnil; Lee, Yang Doo; Kang, Byung Hyun; Yu, Youn-Yeol; Choi, Hyang Hee; Ju, Byeong-Kwon

    2013-01-01

    Carbon nanotubes (CNT) are extremely sensitive to environmental gases. However, detection of mixture gas is still a challenge. Here, we report that 10 ppm of carbon monoxide (CO) and ammonia (NH3) can be electrically detected using a carboxylic acid-functionalized single-walled carbon nanotubes (C-SWCNT). CO and NH3 gases were mixed carefully with the same concentrations of 10 ppm. Our sensor showed faster response to the CO gas than the NH3 gas. The sensing properties and effect of carboxylic acid group were demonstrated, and C-SWCNT sensors with good repeatability and fast responses over a range of concentrations may be used as a simple and effective detection method of CO and NH3 mixture gas.

  1. Competitive assessment of desiccant solar/gas systems for single family residences

    NASA Astrophysics Data System (ADS)

    1982-01-01

    The solar/gas desiccant space conditioning system was compared with competing gas and electric technologies. Benefits and costs to the residential gas customer were evaluated, and practical recommendations regarding an appropriate R&D agenda to maximize the probability of successful development of an advanced desiccant system for that market were provided.

  2. 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.

  3. 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

  4. TiO2 particles on a 3D network of single-walled nanotubes for NH3 gas sensors.

    PubMed

    Jo, Yong Deok; Lee, Sooken; Seo, Jeongeun; Lee, Soobum; Ann, Doyeon; Lee, Haiwon

    2014-12-01

    Ammonia (NH3) gas is one of the gases which causes damage to environment such as acidification and climate change. In this study, a gas sensor based on the three-dimensional (3D) network of single-walled nanotubes (SWNTs) was fabricated for the detection of NH3 gas in dry air. The sensor showed enhanced performance due to the fast gas diffusion rate and weak interactions between the carbon nanotubes and the substrate. Metal oxide particles were introduced to enhance the performance of the gas sensor. Atomic layer deposition (ALD) was employed to deposit the metal oxide in the complex structure, and good control over thickness was achieved. The hybrid gas sensor consisting of the 3D network of SWNTs with anatase TiO2 particles showed stable, repeatable, and enhanced gas sensor performance. The phase of TiO2 particles was characterized by Raman and the morphology of the TiO2 particles on the 3D network of SWNTs was analyzed by transmission electron microscope.

  5. 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.

  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. Redox-switching in a viologen-type adlayer: an electrochemical shell-isolated nanoparticle enhanced Raman spectroscopy study on Au(111)-(1×1) single crystal electrodes.

    PubMed

    Liu, Bo; Blaszczyk, Alfred; Mayor, Marcel; Wandlowski, Thomas

    2011-07-26

    We reported the first application of in situ shell-isolated nanoparticle enhanced Raman spectroscopy (SHINERS) to an interfacial redox reaction under electrochemical conditions. We construct gap-mode sandwich structures composed of a thiol-terminated HS-6V6H viologen adlayer immobilized on a single crystal Au(111)-(1×1) electrode and covered by Au(60 nm)@SiO(2) core-shell nanoparticles acting as plasmonic antennas. We observed high-quality, potential-dependent Raman spectra of the three viologen species V(2+), V(+●), and V(0) on a well-defined Au(111) substrate surface and could map their potential-dependent evolution. Comparison with experiments on powder samples revealed an enhancement factor of the nonresonant Raman modes of ∼3 × 10(5), and up to 9 × 10(7) for the resonance modes. The study illustrates the unique capability of SHINERS and its potential in the entire field of electrochemical surface science to explore structures and reaction pathways on well-defined substrate surfaces, such as single crystals, for molecular, (electro-)catalytic, bioelectrochemical systems up to fundamental double layer studies at electrified solid/liquid interfaces.

  8. Redox-switching in a viologen-type adlayer: an electrochemical shell-isolated nanoparticle enhanced Raman spectroscopy study on Au(111)-(1×1) single crystal electrodes.

    PubMed

    Liu, Bo; Blaszczyk, Alfred; Mayor, Marcel; Wandlowski, Thomas

    2011-07-26

    We reported the first application of in situ shell-isolated nanoparticle enhanced Raman spectroscopy (SHINERS) to an interfacial redox reaction under electrochemical conditions. We construct gap-mode sandwich structures composed of a thiol-terminated HS-6V6H viologen adlayer immobilized on a single crystal Au(111)-(1×1) electrode and covered by Au(60 nm)@SiO(2) core-shell nanoparticles acting as plasmonic antennas. We observed high-quality, potential-dependent Raman spectra of the three viologen species V(2+), V(+●), and V(0) on a well-defined Au(111) substrate surface and could map their potential-dependent evolution. Comparison with experiments on powder samples revealed an enhancement factor of the nonresonant Raman modes of ∼3 × 10(5), and up to 9 × 10(7) for the resonance modes. The study illustrates the unique capability of SHINERS and its potential in the entire field of electrochemical surface science to explore structures and reaction pathways on well-defined substrate surfaces, such as single crystals, for molecular, (electro-)catalytic, bioelectrochemical systems up to fundamental double layer studies at electrified solid/liquid interfaces. PMID:21634391

  9. A sub-50-nm monosized superparamagnetic Fe3O4@SiO2 T2-weighted MRI contrast agent: highly reproducible synthesis of uniform single-loaded core-shell nanostructures.

    PubMed

    Chen, Feng; Bu, Wenbo; Chen, Yu; Fan, Yuchi; He, Qianjun; Zhu, Min; Liu, Xiaohang; Zhou, Liangping; Zhang, Shengjian; Peng, Weijun; Shi, Jianlin

    2009-12-01

    Oleic acid stabilized superparamagnetic iron oxide nanoparticles (SPION) were selected as the cores for fabrication of sub-50-nm monodisperse single-loaded SPION@SiO2 core-shell nanostructures. Parameters that influence the formation of SPION@SiO2 in the water-in-oil reverse microemulsion system have been systematically investigated. The sufficiently high concentration of well-dispersed SPION, together with an appropriately low injection rate of tetraethoxysilane, were found to be the keys to efficiently prevent the homogeneous nucleation of silica and obtain a high-quality single-loaded core-shell nanocomposite. A more detailed mechanism for incorporating oleic acid capped inorganic functional nanoparticles into silica is proposed on the basis of previous reports and our new experimental results. Finally, the as-synthesized SPION@SiO2 nanospheres are exploited as an MRI-enhanced contrast agent, and their contrast effect in solution is tested by using a clinical MRI instrument. PMID:19902450

  10. Single-crystal growth of coordination networks via the gas phase and dependence of iodine encapsulation on the crystal size.

    PubMed

    Kojima, Tatsuhiro; Choi, Wanuk; Kawano, Masaki

    2014-11-18

    Self-assembly of the tripyridyl ligand 2,4,6-tris(4-pyridyl)triazine(TPT) and ZnI2via the gas phase produced three kinds of networks: [(ZnI2)(TPT)]n; [(ZnI2)3(TPT)2]n; and [(ZnI2)(μ-I)(ZnI)(TPT)]n. [(ZnI2)3(TPT)2]n is the first example of the single crystal formation of a porous network via the gas phase and showed the dependence of iodine encapsulation on the crystal size.

  11. 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.

  12. 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.

  13. Measurement of Ultrasound Velocity in the Single Crystal of Black Phosphorus up to 3.3 GPa Gas Pressure

    NASA Astrophysics Data System (ADS)

    Kôzuki, Yasushi; Hanayama, Yoichi; Kimura, Masaki; Nishitake, Teruo; Endo, Shoichi

    1991-05-01

    The effect of hydrostatic pressure on the elastic constants of the single crystal black phosphorus is studied by using a gas pressure apparatus. Neon gas is used as the pressure transmitting medium. A large single crystal of orthorhombic black phosphorus with the dimensions of 5× 3× 6 mm3, has been grown under the condition of 1 GPa and 900°C by using a large solid isotropic compression system. The ultrasound wave velocity is measured by a pulse transmission method up to 3.3 GPa. The longitudinal wave velocities along X and Y axes decreased, while that along Z axis increased. An anomaly was observed around 1.7 GPa, which may be attributed to the vanishing of the energy gap of black phosphorus.

  14. 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).

  15. 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.

  16. 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

    2015-01-01

    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

  17. 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

  18. 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.

  19. Dynamic response of single crystalline copper subjected to quasi-isentropic laser and gas-gun driven loading

    SciTech Connect

    Meyers, M; Jarmakani, H; McNaney, J; Schneider, M; Nguyen, J; Kad, B

    2006-05-22

    Single crystalline copper was subjected to quasi-isentropic compression via gas-gun and laser loading at pressures between 18 GPa and 59 GPa. The deformation substructure was analyzed via transmission electron microscopy (TEM). Twins and laths were evident at the highest pressures, and stacking faults and dislocation cells in the intermediate and lowest pressures, respectively. The Preston-Tonks-Wallace (PTW) constitutive description was used to model the slip-twinning process in both cases.

  20. Pyrolysis GC/MS and IR spectroscopy in chitin analysis of molluscan shells.

    PubMed

    Furuhashi, Takeshi; Beran, Anton; Blazso, Marianne; Czegeny, Zsuzsanna; Schwarzinger, Clemens; Steiner, Gerhard

    2009-01-01

    Chitin is an insoluble component in the shells of several molluscan species. It is thought to play important roles, in biomineralization and shell structure. To date, however, reports are scarce and sometimes contradictory, and suffer from methodological problems. Only in a single cephalopod species has the chitin been identified as beta-chitin. We present data on chitin occurrence in 22 species of shell-bearing Mollusca (Conchifera) and Polyplacophora, including the first evidence for scaphopods, based on pyrolysis gas chromatography, mass spectrometry (GC-MS), and infrared spectroscopy (IR). Pyrolysis GC-MS detected chitin in every tested member of the Conchifera. IR spectroscopy before and after chitinase treatment revealed at least three distinct patterns of peak changes. The contents of the insoluble shell organics included not only chitin and proteins, but also insoluble polysaccharides, e.g., glucan. We conclude that chitin was present in the last common ancestor of the Conchifera and that its abundance in the shell matrix depends on the differentiation of the shell. PMID:19129649

  1. 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.

  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. A single glucose derivative suitable for gas chromatography/mass spectrometry and gas chromatography/combustion/isotope ratio mass spectrometry.

    PubMed

    Jackson, Sarah J; Waterhouse, John S; Bluck, Leslie J C

    2007-01-01

    The incorporation of stable isotopes improves the assessment of glucose metabolism and, with some researchers using two tracers, (2)H-glucose assessed by gas chromatography/mass spectrometry (GC/MS) and (13)C-glucose by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS), a common derivative for both is advantageous. The most commonly used derivatives for GC/MS are inappropriate for GC/C/IRMS as additional functional groups dilute the label. We therefore considered the suitability of six derivatives for both GC/MS and GC/C/IRMS. Glucose alkylboronates were prepared by adding the appropriate alkylboronic acid (butyl- or methylboronic acid) in pyridine to desiccated glucose. The derivatisation was completed by reacting this with either (a) acetic anhydride or trifluoroacetic anhydride (acetate derivatives) or (b) bis(trimethylsilyl)trifluoroacetamide BSTFA (TMS derivatives). All six derivatives were assessed using GC/MS and (13)C GC/C/IRMS. Neither TMS derivative exhibited any signal intensity in the molecular ion, although a M-15 ion showed good agreement between experimental and theoretical data and, whilst still low in intensity, could be suitable for isotope work. Similarly, none of the acetate derivatives showed any intensity at the molecular ion although three key fragmentation series were identified. The most attractive sequence, initiated by the loss of 1,2 cyclic boronate, resulted in the main fragment ion of interest, m/z 240, corresponding to the fluorinated methylboronate derivate. Minimal carbon and hydrogen atoms are added to this derivative making it an excellent choice for stable isotope work, while proving suitable for analysis by both GC/MS and GC/C/IRMS.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Influence of the Gas Pressure on Single-wall Carbon Nanotubes Formation

    NASA Technical Reports Server (NTRS)

    Hinkov, I.; Farhat, S.; Scott, C. D.

    2005-01-01

    Experiments and modeling have been performed to predict the effect of gas pressure on species distribution and nanotube growth rate under specific conditions of synthesis of singlewall carbon nanotubes (SWCNTs) by arc discharge. Numerical results were compared with experiments in order to find a consistent correlation between the nanotube growth and the pressure. We used argon and helium as buffer gases with a total pressure varied between 0.1 and 1 bar. We experimentally observed that both the anode erosion rate and the Brunauer-Emmett-Teller (BET) surface area of the as produced nanotube soot material are very sensitive to the total gas pressure in the reactor

  9. Enrichment and determination of polybrominated diphenyl ethers in environmental water samples by magnetic solid-phase extraction with core-shell magnetic carbon microspheres before gas chromatography with mass spectrometry.

    PubMed

    Zhou, Jia-Bin; She, Xiao-Kun; Xing, Han-Zhu; Wang, Xia; Zhao, Ru-Song

    2016-05-01

    Core-shell magnetic carbon microspheres were synthesized by a simple hydrothermal method and used as a novel magnetic solid-phase extraction adsorbent for the sensitive determination of polybrominated diphenyl ethers in environmental water samples. Gas chromatography with negative chemical ionization mass spectrometry was adopted for the detection. Box-Behnken design was used to investigate and optimize important magnetic solid-phase extraction parameters through response surface methodology. Under the optimal conditions, low limits of detection (0.07-0.17 ng·L(-1) ), a wide linear range (1-1000 ng·L(-1) ), and good repeatability (0.80-4.58%) were achieved. The developed method was validated with several real water samples, and satisfactory results were obtained in the range of 72.8-97.9%. These results indicated that core-shell magnetic carbon microspheres have great potential as an adsorbent for the magnetic solid-phase extraction of polybrominated diphenyl ethers at trace levels from environmental water samples.

  10. 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.

  11. 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.

  12. Variability in shell models of GRBs

    SciTech Connect

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

    1997-09-01

    Many cosmological models of gamma-ray bursts (GRBs) assume that a single relativistic shell carries kinetic energy away from the source and later converts it into gamma rays, perhaps by interactions with the interstellar medium or by internal shocks within the shell. Although such models are able to reproduce general trends in GRB time histories, it is difficult to reproduce the high degree of variability often seen in GRBs. The authors investigate methods of achieving this variability using a simplified external shock model. Since the model emphasizes geometric and statistical considerations, rather than the detailed physics of the shell, it is applicable to any theory that relies on relativistic shells. They find that the variability in GRBs gives strong clues to the efficiency with which the shell converts its kinetic energy into gamma rays.

  13. Synthesis and Gas Sensing Properties of Single La-Doped SnO2 Nanobelts

    PubMed Central

    Wu, Yuemei; Zhang, Heng; Liu, Yingkai; Chen, Weiwu; Ma, Jiang; Li, Shuanghui; Qin, Zhaojun

    2015-01-01

    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. PMID:26087374

  14. 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.

  15. 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.

  16. 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.

  17. A single-vial analytical and quantitative gas chromatography-mass spectrometry assay for terpene synthases.

    PubMed

    O'Maille, Paul E; Chappell, Joe; Noel, Joseph P

    2004-12-15

    A quantitative assay for the analysis of sesquiterpene synthases, wherein each reaction mixture is formulated in glass gas chromatography vials, overlaid with organic solvent such as ethyl acetate, and subsequently vortexed to extract hydrocarbon reaction products into the organic phase after a suitable incubation period, was developed. The product-enriched organic phase is then sampled in an automated fashion and injected directly into a gas chromatograph-mass spectrometer without further workup for analysis and quantification of hydrocarbon products. Application of the vial assay to the analysis of amorpha-4,11-diene synthase (ADS), a sesquiterpene synthase, demonstrated the sensitivity of the assay for detection of major and minor reaction products and most notably for the identification of several sesquiterpene products that had escaped previous detection. A steady-state kinetic analysis of tobacco 5-epi-aristolochene synthase (TEAS), another sesquiterpene synthase, validated the quantitative nature of the assay, providing an alternative means to the established method of using radiolabeled substrate, extraction, and scintillation counting. This simplified assay provides a standardized method to facilitate analysis of terpene synthases and diverse mutant enzyme libraries by supplanting the common practice of using larger scale reactions, multiple extractions, and evaporative concentration of the organic phase prior to gas chromatography-mass spectrometry (GC-MS) analysis. PMID:15556559

  18. Viscous slip coefficients for binary gas mixtures measured from mass flow rates through a single microtube

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Takamori, K.; Perrier, P.; Graur, I.; Matsuda, Y.; Niimi, T.

    2016-09-01

    The viscous slip coefficient for helium-argon binary gas mixture is extracted from the experimental values of the mass flow rate through a microtube. The mass flow rate is measured by the constant-volume method. The viscous slip coefficient was obtained by identifying the measured mass flow rate through a microtube with the corresponding analytical expression, which is a function of the Knudsen number. The measurements were carried out in the slip flow regime where the first-order slip boundary condition can be applied. The measured viscous slip coefficients of binary gas mixtures exhibit a concave function of the molar ratio of the mixture, showing a similar profile with numerical results. However, from the detailed comparison between the measured and numerical values with the complete and incomplete accommodation at a surface, it is inappropriate to estimate the viscous slip coefficient for the mixture numerically by employing separately measured tangential momentum accommodation coefficient for each component. The time variation of the molar ratio in the downstream chamber was measured by sampling the gas from the chamber using the quadrupole mass spectrometer. In our measurements, it is indicated that the volume flow rate of argon is larger than that of helium because of the difference in the tangential momentum accommodation coefficient.

  19. Classification Shell Game.

    ERIC Educational Resources Information Center

    Etzold, Carol

    1983-01-01

    Discusses shell classification exercises. Through keying students advanced from the "I know what a shell looks like" stage to become involved in the classification process: observing, labeling, making decisions about categories, and identifying marine animals. (Author/JN)

  20. The use of hydrogen gas clearance for blood flow measurements in single endogenous and transplanted pancreatic islets.

    PubMed

    Barbu, Andreea; Jansson, Leif; Sandberg, Monica; Quach, My; Palm, Fredrik

    2015-01-01

    The blood perfusion of pancreatic islets is regulated independently from that of the exocrine pancreas, and is of importance for multiple aspects of normal islet function, and probably also during impaired glucose tolerance. Single islet blood flow has been difficult to evaluate due to technical limitations. We therefore adapted a hydrogen gas washout technique using microelectrodes to allow such measurements. Platinum micro-electrodes monitored hydrogen gas clearance from individual endogenous and transplanted islets in the pancreas of male Lewis rats and in human and mouse islets implanted under the renal capsule of male athymic mice. Both in the rat endogenous pancreatic islets as well as in the intra-pancreatically transplanted islets, the vascular conductance and blood flow values displayed a highly heterogeneous distribution, varying by factors 6-10 within the same pancreas. The blood flow of human and mouse islet grafts transplanted in athymic mice was approximately 30% lower than that in the surrounding renal parenchyma. The present technique provides unique opportunities to study the islet vascular dysfunction seen after transplantation, but also allows for investigating the effects of genetic and environmental perturbations on islet blood flow at the single islet level in vivo.

  1. 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

  2. Formation of single-wall carbon nanotubes in Ar and nitrogen gas atmosphere by using laser furnace technique

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Asai, N.; Kataura, H.; Achiba, Y.

    2007-07-01

    The formation of single-wall carbon nanotubes (SWNTs) by using laser vaporization technique in different ambient gas atmosphere was investigated. SWNTs were prepared with Rh/Pd (1.2/1.2 atom%)-carbon composite rod in Ar and nitrogen gas atmosphere, respectively. Raman spectra of raw carbon materials including SWNTs and photoluminescence mapping of dispersed SWNTs in a surfactant solution demonstrate that the diameter distribution of SWNTs prepared in Ar atmosphere is narrower than those obtained by using CVD technique (e.g. HiPco nanotube), even when the ambient temperature is as high as 1150 ?C. It was also found that nitrogen atmosphere gives wider diameter distribution of SWNTs than that obtained with Ar atmosphere. Furthermore, the relative yield of fullerenes (obtained as byproducts) is investigated by using HPLC (high-performance liquid chromatography) technique. It was found that the relative yield of higher fullerenes becomes lower, when nitrogen is used as an ambient gas atmosphere. Based on these experimental findings, a plausible formation mechanism of SWNTs is discussed.

  3. Nanoscale Effects on Heterojunction Electron Gases in GaN/AlGaN Core/Shell Nanowires

    PubMed Central

    2011-01-01

    The electronic properties of heterojunction electron gases formed in GaN/AlGaN core/shell nanowires with hexagonal and triangular cross sections are studied theoretically. We show that at nanoscale dimensions, the nonpolar hexagonal system exhibits degenerate quasi-one-dimensional electron gases at the hexagon corners, which transition to a core-centered electron gas at lower doping. In contrast, polar triangular core/shell nanowires show either a nondegenerate electron gas on the polar face or a single quasi-one-dimensional electron gas at the corner opposite the polar face, depending on the termination of the polar face. More generally, our results indicate that electron gases in closed nanoscale systems are qualitatively different from their bulk counterparts. PMID:21696178

  4. Comparison of axisymmetric and three-dimensional models for gas uptake in a single bifurcation during steady expiration.

    PubMed

    Madasu, Srinath; Ultman, James S; Borhan, Ali

    2008-02-01

    Reactive gas uptake is predicted and compared in a single bifurcation at steady expiratory flow in terms of Sherwood number using an axisymmetric single-path model (ASPM) and a three-dimensional computational fluid dynamics model (CFDM). ASPM is validated in a two-generation geometry by comparing the average gas-phase mass transfer coefficients with the experimental values. ASPM predicted mass transfer coefficients within 20% of the experimental values. The flow and concentration variables in the ASPM were solved using Galerkin finite element method and in the CFDM using commercial finite element software FIDAP. The simulations were performed for reactive gas flowing at Reynolds numbers ranging from 60 to 350 in both symmetric bifurcation for three bifurcation angles, 30 deg, 70 deg, and 90 deg, and in an asymmetric bifurcation. The numerical models compared with each other qualitatively but quantitatively they were within 0.4-8% due to nonfully developed flow in the parent branch predicted by the CFDM. The radially averaged concentration variation along the axial location matched qualitatively between the CFDM and ASPM but quantitatively they were within 32% due to differences in the flow field. ASPM predictions compared well with the CFDM predictions for an asymmetric bifurcation. These results validate the simplified ASPM and the complex CFDM. ASPM predicts higher Sherwood number with a flat velocity inlet profile compared to a parabolic inlet velocity profile. Sherwood number increases with the inlet average velocity, wall mass transfer coefficient, and bifurcation angle since the boundary layer grows slower in the parent and daughter branches.

  5. Tunable Diacetylene Polymerized Shell Microbubbles as Ultrasound Contrast Agents

    PubMed Central

    Park, Yoonjee; Luce, Adam C.; Whitaker, Ragnhild D.; Amin, Bhumica; Cabodi, Mario; Nap, Rikkert J.; Szleifer, Igal; Cleveland, Robin O.; Nagy, Jon O.; Wong, Joyce Y.

    2012-01-01

    Monodisperse gas microbubbles, encapsulated with a shell of photopolymerizable diacetylene lipids and phospholipids, were produced by microfluidic flow focusing, for use as ultrasound contrast agents. The stability of the polymerized shell microbubbles against both aggregation and gas dissolution under physiological conditions was studied. Polyethylene glycol (PEG) 5000, which was attached to the diacetylene lipids, was predicted by molecular theory to provide more steric hindrance against aggregation than PEG 2000 and this was confirmed experimentally. The polymerized shell microbubbles were found to have higher shell-resistance than nonpolymerizable shell microbubbles and commercially available microbubbles (Vevo MicroMarker). The acoustic stability under 7.5 MHz ultrasound insonation was significantly greater than for the two comparison microbubbles. The acoustic stability was tunable by varying the amount of diacetylene lipid. Thus, our polymerized shell microbubbles are a promising platform for ultrasound contrast agents. PMID:22260537

  6. Continuously tunable single-frequency 1.52-{mu}m diode laser for gas analysis

    SciTech Connect

    Gladyshev, A V; Belovolov, M I; Vasil'ev, Sergei A; Medvedkov, O I; Duraev, V P; Nedelin, E T; Nadezhdinskii, Aleksandr I; Ponurovskii, Ya Ya

    2005-03-31

    A single-frequency continuously tunable diode laser with a hybrid fibre Bragg grating resonator (hybrid laser) is built for recording the absorption line of ammonia. The continuous tuning within 40 GHz (1.33 cm{sup -1}) was achieved for the first time for a hybrid laser emitting 5 mW in the line of width {delta}{nu} {<=} 15 MHz (0.0005 cm{sup -1}) with the side-mode suppression exceeding 20 dB. (lasers)

  7. Kramers' Restricted Closed Shell CCSD Theory

    NASA Technical Reports Server (NTRS)

    Visscher, Lucas; Dyall, Kenneth G.; Lee, Timothy J.; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    A Kramers' restricted version of the closed shell coupled cluster singles doubles theory is presented. The theory may be used in conjunction with 2 or 4-component relativistic reference wavefunctions. The intrinsic treatment of the spin-orbit coupling doubles the number of independent quantities (amplitudes and integrals) relative to a spin-independent formalism. The number of operations required to evaluate the equations is four times larger than in the optimal spin-independent closed shell formalism.

  8. 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.

  9. Glass shell manufacturing in space

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    Highly-uniform, hollow glass spheres, which are used for inertial-confinement fusion targets, are formed from metal-organic gel powder feedstock in a drop-tower furnace. The modelling of this gel-to-sphere transformation has consisted of three phases: gel thermochemistry, furnance-to-gel heat transfer, and gravity-driven degradation of the concentricity of the molten shell. The heat transfer from the furnace to the free-falling gel particle was modelled with forced convection. The gel mass, dimensions, and specific heat as well as furnace temperature profile and furnace gas conductivity, were controlled variables. This model has been experimentally verified. In the third phase, a mathematical model was developed to describe the gravity-driven degradation of concentricity in molten glass shells.

  10. The shell coal gasification process

    SciTech Connect

    Koenders, L.O.M.; Zuideveld, P.O.

    1995-12-01

    Future Integrated Coal Gasification Combined Cycle (ICGCC) power plants will have superior environmental performance and efficiency. The Shell Coal Gasification Process (SCGP) is a clean coal technology, which can convert a wide range of coals into clean syngas for high efficiency electricity generation in an ICGCC plant. SCGP flexibility has been demonstrated for high-rank bituminous coals to low rank lignites and petroleum coke, and the process is well suited for combined cycle power generation, resulting in efficiencies of 42 to 46% (LHV), depending on choice of coal and gas turbine efficiency. In the Netherlands, a 250 MWe coal gasification combined cycle plant based on Shell technology has been built by Demkolec, a development partnership of the Dutch Electricity Generating Board (N.V. Sep). The construction of the unit was completed end 1993 and is now followed by start-up and a 3 year demonstration period, after that the plant will be part of the Dutch electricity generating system.

  11. Premature detonation problem. [Artillery shells

    SciTech Connect

    Pimbley, G.H.; Marshall, E.F.

    1980-05-01

    Determining how cavities or voids in the explosive loads of artillery shells cause in-bore premature detonations is important to military authorities. Though answers continue to be elusive, in detailing recent studies of the problem at LASL, some traditional approaches were examined and a new direction of investigation is suggested. The aquarium experiment and the pipe test were devised at LASL to model the events taking place in a base gap, or in an internal cavity, in the load of an accelerating artillery shell. Numerical simulation was used to assess the data from these experiments. Both the experimental and the numerical simulation phases of the project are described. The commonly accepted gas compression, thermal ignition mechanism is not consistent with the results of this study. The dominant mechanism or mechanisms have not been identified.

  12. 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

    2013-11-01

    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.

  13. Nonequilibrium Fluctuations for a Single-Particle Analog of Gas in a Soft Wall

    NASA Astrophysics Data System (ADS)

    Lee, Dong Yun; Kwon, Chulan; Pak, Hyuk Kyu

    2015-02-01

    We investigate the motion of a colloidal particle driven out of equilibrium by a time-varying stiffness of the optical trap that produces persistent nonequilibrium work. Measurements of work production for repeated cycles composed of the compression and expansion processes for the optical potential show huge fluctuations due to thermal motion. Using a precise technique to modulate the stiffness in time, we accurately estimate the probability distributions of work produced for the compression and expansion processes. We confirm the fluctuation theorem from the ratio of the two distributions. We also show that the average values of work for the two processes comply with the Jarzynski equality. This system has an analogy with a gas in a breathing soft wall. We discuss about its applicability to a heat engine and an information engine operated by feedback control.

  14. Nanostructued core-shell Sn nanowires @ CNTs with controllable thickness of CNT shells for lithium ion battery

    NASA Astrophysics Data System (ADS)

    Zhong, Yu; Li, Xifei; Zhang, Yong; Li, Ruying; Cai, Mei; Sun, Xueliang

    2015-03-01

    Core-shell structure of Sn nanowires encapsulated in amorphous carbon nanotubes (Sn@CNTs) with controlled thickness of CNT shells was in situ prepared via chemical vapor deposition (CVD) method. The thickness of CNT shells was accurately controlled from 4 to 99 nm by using different growth time, flow rate of hydrocarbon gas (C2H4) and synthesis temperature. The microstructure and composition of the coaxial Sn@CNTs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM) techniques. Moreover, the Sn@CNTs were studied as anode materials for Li-ion batteries and showed excellent cycle performance. The capacity was affected by the thickness of outer CNT shells: thick CNT shells contributed to a better retention while thin CNT shells led to a higher capacity. The thin CNT shell of 6 nm presented the highest capacity around 630 mAh g-1.

  15. Shell nuclear explosions in degenerate dwarfs

    NASA Astrophysics Data System (ADS)

    Kuznetsov, O. A.; Tutukov, A. V.; Chechetkin, V. M.

    1989-08-01

    Numerical gas dynamics simulations are used to study shell nuclear explosions of degenerate carbon-oxygen dwarfs with masses of 1.17, 1.36, and 1.42 solar masses. It is assumed that the calorific capacity of the burning shell matter is between 5 X 10 to the 17th and 5 X 10 to the 18th erg/g. It is shown that, at a low calorific capacity, a remnant may form if the mass of the shell is less than 90 percent of the mass of the degenerate dwarf. In the case of high calorific capacity, a remnant may form only if the mass of the shell is less than half of the dwarf's mass.

  16. VOC-Induced Flexing of Single and Multilayer Polyethylene Films As Gas Sensors.

    PubMed

    Alipour, Nazanin; Andersson, Richard L; Olsson, Richard T; Gedde, Ulf W; Hedenqvist, Mikael S

    2016-04-20

    The differential swelling and bending of multilayer polymeric films due to the dissimilar uptake of volatile organic compounds (VOCs; n-hexane, limonene) in the different layers was studied. Motions of thin polyethylene films triggered by the penetrant were investigated to learn more about how their deformation is related to VOC absorption. Single layers of metallocene or low-density polyethylene, and multilayers (2-288 layers) of these in alternating positions were considered. Single-, 24-, and 288-layer films displayed no motion when uniformly subjected to VOCs, but they could display simple curving modes when only one side of the film was wetted with a liquid VOC. Two-layer films displayed simple bending when uniformly subjected to VOCs due to the different swelling in the two layers, but when the VOC was applied to only one side of the film, more complex modes of motion as well as dynamic oscillations were observed (e.g., constant amplitude wagging at 2 Hz for ca. 50 s until all the VOC had evaporated). Diffusion modeling was used to study the transport behavior of VOCs inside the films and the different bending modes. Finally a prototype VOC sensor was developed, where the reproducible curving of the two-layer film was calibrated with n-hexane. The sensor is simple, cost-efficient, and nondestructive and requires no electricity. PMID:27023792

  17. Enhanced ethanol sensing properties of TiO2/ZnO core-shell nanorod sensors

    NASA Astrophysics Data System (ADS)

    Park, Sunghoon; An, Soyeon; Ko, Hyunsung; Lee, Sangmin; Kim, Hyoun Woo; Lee, Chongmu

    2014-06-01

    TiO2-core/ZnO-shell nanorods were synthesized using a two-step process: the synthesis of TiO2 nanorods using a hydrothermal method followed by atomic layer deposition of ZnO. The mean diameter and length of the nanorods were ˜300 nm and ˜2.3 μm, respectively. The cores and shells of the nanorods were monoclinic-structured single-crystal TiO2 and wurtzite-structured single-crystal ZnO, respectively. The multiple networked TiO2-core/ZnO-shell nanorod sensors showed responses of 132-1054 % at ethanol (C2H5OH) concentrations ranging from 5 to 25 ppm at 150 ∘C. These responses were 1-5 times higher than those of the pristine TiO2 nanorod sensors at the same C2H5OH concentration range. The substantial improvement in the response of the pristine TiO2 nanorods to C2H5OH gas by their encapsulation with ZnO may be attributed to the enhanced absorption and dehydrogenation of ethanol. In addition, the enhanced sensor response of the core-shell nanorods can be attributed partly to changes in resistance due to both the surface depletion layer of each core-shell nanorod and the potential barriers built in the junctions caused by a combination of homointerfaces and heterointerfaces.

  18. A Plasma Opening Switch Based on a Gas-Puff/Axial Wire Configuration

    NASA Astrophysics Data System (ADS)

    Engelbrecht, Joseph; de Grouchy, Philip; Ouart, Nicholas; Qi, Niansheng; Atoyan, Levon; Banasek, Jacob; Potter, William; Hammer, David; Kusse, Bruce; Giuliani, John

    2015-11-01

    We are investigating an idea for switching current from a gas-puff shell to an axial metal wire as a mechanism for generating inductive voltage spikes and x-rays above 10 keV. The outer annulus of a 7 cm. diameter triple-annular gas-puff nozzle is used to inject gas into the electrode gap of the COBRA 1 MA generator, with a single wire on-axis. We show that the current pulse produced by COBRA initially travels through the lower inductance pre-ionized outer shell plasma, generating an azimuthal magnetic field which drives this shell radially inwards. Rayleigh-Taylor instability growth occurs on the outer edge of this imploding plasma, which disrupts the current carrying column, inhibiting the axial flow of current through the gas-puff plasma and possibly causing the current to switch to the higher inductance wire. A disruption to the current through the gas-puff shell caused by instability growth should be measurable as a voltage spike, as the current finds a new path either through the wire or elsewhere in the imploding plasma shell. We investigate this effect as instability conditions are varied, by adjusting the density and species of the injected gas. This work was sponsored by the NNSA Stewardship Sciences Academic Programs under DOE cooperative agreement.

  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. 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.

  2. 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.

  3. Headspace Single-Drop Microextraction Gas Chromatography Mass Spectrometry for the Analysis of Volatile Compounds from Herba Asari

    PubMed Central

    Wang, Guan-Jie; Tian, Li; Fan, Yu-Ming; Qi, Mei-Ling

    2013-01-01

    A rapid headspace single-drop microextraction gas chromatography mass spectrometry (SDME-GC-MS) for the analysis of the volatile compounds in Herba Asari was developed in this study. The extraction solvent, extraction temperature and time, sample amount, and particle size were optimized. A mixed solvent of n-tridecane and butyl acetate (1 : 1) was finally used for the extraction with sample amount of 0.750 g and 100-mesh particle size at 70°C for 15 min. Under the determined conditions, the pound samples of Herba Asari were directly applied for the analysis. The result showed that SDME-GC–MS method was a simple, effective, and inexpensive way to measure the volatile compounds in Herba Asari and could be used for the analysis of volatile compounds in Chinese medicine. PMID:23607049

  4. Taguchi Based Regression Analysis of End-Wall Film Cooling in a Gas Turbine Cascade with Single Row of Holes

    NASA Astrophysics Data System (ADS)

    Ravi, D.; Parammasivam, K. M.

    2016-09-01

    Numerical investigations were conducted on a turbine cascade, with end-wall cooling by a single row of cylindrical holes, inclined at 30°. The mainstream fluid was hot air and the coolant was CO2 gas. Based on the Reynolds number, the flow was turbulent at the inlet. The film hole row position, its pitch and blowing ratio was varied with five different values. Taguchi approach was used in designing a L25 orthogonal array (OA) for these parameters. The end-wall averaged film cooling effectiveness (bar η) was chosen as the quality characteristic. CFD analyses were carried out using Ansys Fluent on computational domains designed with inputs from OA. Experiments were conducted for one chosen OA configuration and the computational results were found to correlate well with experimental measurements. The responses from the CFD analyses were fed to the statistical tool to develop a correlation for bar η using regression analysis.

  5. Fluctuating shells under pressure

    PubMed Central

    Paulose, Jayson; Vliegenthart, Gerard A.; Gompper, Gerhard; Nelson, David R.

    2012-01-01

    Thermal fluctuations strongly modify the large length-scale elastic behavior of cross-linked membranes, giving rise to scale-dependent elastic moduli. Whereas thermal effects in flat membranes are well understood, many natural and artificial microstructures are modeled as thin elastic shells. Shells are distinguished from flat membranes by their nonzero curvature, which provides a size-dependent coupling between the in-plane stretching modes and the out-of-plane undulations. In addition, a shell can support a pressure difference between its interior and its exterior. Little is known about the effect of thermal fluctuations on the elastic properties of shells. Here, we study the statistical mechanics of shape fluctuations in a pressurized spherical shell, using perturbation theory and Monte Carlo computer simulations, explicitly including the effects of curvature and an inward pressure. We predict novel properties of fluctuating thin shells under point indentations and pressure-induced deformations. The contribution due to thermal fluctuations increases with increasing ratio of shell radius to thickness and dominates the response when the product of this ratio and the thermal energy becomes large compared with the bending rigidity of the shell. Thermal effects are enhanced when a large uniform inward pressure acts on the shell and diverge as this pressure approaches the classical buckling transition of the shell. Our results are relevant for the elasticity and osmotic collapse of microcapsules. PMID:23150558

  6. 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.

  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. 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.

  9. 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.

  10. 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.

  11. 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.

  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.; 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 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. Synthesis of Core-shell Structured Amorphous Si Nanoparticles by Induction Thermal Plasmas

    NASA Astrophysics Data System (ADS)

    Okamoto, Daisuke; Kageyama, Takuya; Tanaka, Manabu; Sone, Hirotaka; Watanabe, Takayuki

    2015-09-01

    Core-shell structured amorphous Si nanoparticles were synthesized by induction thermal plasma. Crystalline Si powder with 3 μm of average diameter was injected into the induction thermal plasma at 4 MHz. The Si raw materials immediately evaporate in the high temperature plasma region and nanoparticles were produced through the quenching process. Counterflow quenching gas was injected from downstream of the torch with its direction against the plasma flow. The effect of the operating parameter such as flow rate of quenching gas and input power was investigated. Collected particles were characterized by X-ray diffraction, transmission electron microscopy, electron energy-loss spectroscopy, and Raman spectroscopy. Obtained results indicate that amorphization degree of the synthesized nanoparticles is more than 90% when additional quenching gas of 20 L/min is injected. The quenching rate of the prepared nanoparticles in the growth region have an important role on determining the amorphization degree. Moreover, EELS and Raman analyses showed the synthesized nanoparticles were coated by the SiO2 shell with thickness of 2-4 nm. These findings indicated that amorphous Si/SiO2 core-shell structured nanoparticles were successfully synthesized by induction thermal plasma in single step.

  14. Symmetries and deformations in the spherical shell model

    NASA Astrophysics Data System (ADS)

    Van Isacker, P.; Pittel, S.

    2016-02-01

    We discuss symmetries of the spherical shell model that make contact with the geometric collective model of Bohr and Mottelson. The most celebrated symmetry of this kind is SU(3), which is the basis of Elliott’s model of rotation. It corresponds to a deformed mean field induced by a quadrupole interaction in a single major oscillator shell N and can be generalized to include several major shells. As such, Elliott’s SU(3) model establishes the link between the spherical shell model and the (quadrupole component of the) geometric collective model. We introduce the analogue symmetry induced by an octupole interaction in two major oscillator shells N-1 and N, leading to an octupole-deformed solution of the spherical shell model. We show that in the limit of large oscillator shells, N\\to ∞ , the algebraic octupole interaction tends to that of the geometric collective model.

  15. Size-selective yolk-shell nanoreactors with nanometer-thin porous polymer shells.

    PubMed

    Jia, Ying; Shmakov, Sergey N; Register, Paul; Pinkhassik, Eugene

    2015-09-01

    Yolk-shell nanoreactors with metal nanoparticle core and ultrathin porous polymer shells are effective catalysts for heterogeneous reactions. Polymer shells provide size-selectivity and improved reusability of catalyst. Nanocapsules with single-nanometer porous shells are prepared by vesicle-templated directed assembly. Metal nanoparticles are formed either by selective initiation in pre-fabricated nanocapsules or simultaneously with the creation of a crosslinked polymer shell. In this study, we investigated the oxidation of benzyl alcohol and benzaldehyde catalyzed by gold nanoparticles and hydrogenation of cyclohexene catalyzed by platinum nanoparticles. Comparison of newly created nanoreactors with commercially available nanoparticles revealed superior reusability and size selectivity in nanoreactors while showing no negative effect on reaction kinetics.

  16. Determination of pesticide residues in honey by single-drop microextraction and gas chromatography.

    PubMed

    Tsiropoulos, Nikolaos G; Amvrazi, Elpiniki G

    2011-01-01

    A novel, simple, and rapid single-drop microextraction (SDME) procedure combined with GC has been developed, validated, and applied for the determination of multiclass pesticide residues in honey samples. The SDME was optimized using a Plackett-Burman screening design considering all parameters that may influence an SDME procedure and a consequent central composite design to control the parameters that were found to significantly influence the pesticide determination. The developed analytical method required minimal volumes of organic solvents and exhibited good analytical characteristics with enrichment factors ranging from 3 for alpha-endosulfan to 10 for lindane, procymidone, and captan and method quantification limits ranging from 0.03 microg/kg for phosalone to 10.6 microg/kg for diazinon. The relative recoveries obtained ranged from 70.8% for captan to 120% for fenarimol, and the precision (RSD) ranged from 3 to 15%. The proposed SDME procedure followed by GC with an electron capture detector for quantification and GC/MS for identification was applied with success to the analysis of 17 honey samples. Monitoring results indicated a low level of honey contamination by diazinon, chlorpyrifos-ethyl, procymidone, bromopropylate, and endosulfan (alpha-, beta-, and endosulfan sulfate) residues that were far below the maximum residue limit values specified by the European Union for endosulfan (10 microg/kg) and bromopropylate (100 microg/kg) in honey samples. PMID:21563700

  17. 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.

  18. Adsorbing H₂S onto a single graphene sheet: A possible gas sensor

    SciTech Connect

    Reshak, A. H.; Auluck, S.

    2014-09-14

    The electronic structure of pristine graphene sheet and the resulting structure of adsorbing a single molecule of H₂S on pristine graphene in three different sites (bridge, top, and hollow) are studied using the full potential linearized augmented plane wave method. Our calculations show that the adsorption of H₂S molecule on the bridge site opens up a small direct energy gap of about 0.1 eV at symmetry point M, while adsorption of H₂S on top site opens a gap of 0.3 eV around the symmetry point K. We find that adsorbed H₂S onto the hollow site of pristine graphene sheet causes to push the conduction band minimum and the valence band maximum towards Fermi level resulting in a metallic behavior. Comparing the angular momentum decomposition of the atoms projected electronic density of states of pristine graphene sheet with that of H₂S–graphene for three different cases, we find a significant influence of the location of the H₂S molecule on the electronic properties especially the strong hybridization between H₂S molecule and graphene sheet.

  19. Wall effects on the thermocapillary migration of single gas bubbles in stagnant liquids

    NASA Astrophysics Data System (ADS)

    Alhendal, Yousuf; Turan, Ali; Kalendar, Abdulrahim

    2016-09-01

    In this paper, the governing continuum conservation equations for two-phase flow are solved using the commercial software package (Ansys-Fluent 1) to investigate the thermocapillary movement of a single bubble in stagnant liquid under zero-gravity condition. The current results show that different temperature gradients lead to different bubble migration velocities, and bubble migration velocity varies linearly with the temperature gradient for the given conditions. Furthermore the inside column diameter was found to have a significant influence on the thermocapillary migration of the bubble. Calculation were made in columns with inside diameters Dr 15, 20, 30, 40, 60, 80, 100 and 120 mm. Reduction on bubble migration velocity only occurred when the ratio of the bubble diameter to the column diameter, db/Dr, is greater than 0.267 due to column wall effect. On the other hand, the influence of the column diameter on the rise velocity is negligible when db/Dr is equal to or smaller than 0.267. No bubble shape deformation were observed and the bubble were spherical in shape for all column width. Present investigation of the shape and trajectory of bubble motion driven by surface tension-gradient in different column width is a new area of study and aims to support research into space applications which can help to determine the new migration time and speed.

  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 .

  1. Multiple shell fusion targets

    DOEpatents

    Lindl, J.D.; Bangerter, R.O.

    1975-10-31

    Multiple shell fusion targets for use with electron beam and ion beam implosion systems are described. The multiple shell targets are of the low-power type and use a separate relatively low Z, low density ablator at large radius for the outer shell, which reduces the focusing and power requirements of the implosion system while maintaining reasonable aspect ratios. The targets use a high Z, high density pusher shell placed at a much smaller radius in order to obtain an aspect ratio small enough to protect against fluid instability. Velocity multiplication between these shells further lowers the power requirements. Careful tuning of the power profile and intershell density results in a low entropy implosion which allows breakeven at low powers. For example, with ion beams as a power source, breakeven at 10-20 Terrawatts with 10 MeV alpha particles for imploding a multiple shell target can be accomplished.

  2. Evaluation of a miniaturised single-stage thermal modulator for comprehensive two-dimensional gas chromatography of petroleum contaminated soils.

    PubMed

    Jacobs, Matthew R; Edwards, Matthew; Górecki, Tadeusz; Nesterenko, Pavel N; Shellie, Robert A

    2016-09-01

    A novel miniaturised single-stage resistively heated thermal modulator was investigated as an alternative to cryogenic modulation for use in comprehensive two-dimensional gas chromatography (GC×GC). The single-stage thermal modulator described herein yielded average retention time relative standard deviations (RSD) of ≤0.2% RSD (first-dimension) and ≤3.4% RSD (second-dimension). The average peak widths generated by the modulator were 72±3ms, and the peak area precision was better than 5.3% RSD for a range of polar and non-polar test analytes. GC×GC analysis can be performed using this modulator without the requirement for cryogenic cooling or additional pressure control modules for flow modulation. The modulator and associated electronics are compact and amenable towards field analysis. The modulator was used for qualitative and quantitative characterisation of petroleum-contaminated soils derived from a sub-Antarctic research station at Macquarie Island. The limit of detection compared to standard 1D GC analysis was improved from 64 to 11mgkg(-1). An automated method of analysing and categorising samples using principal component analysis is presented. PMID:27527879

  3. Evaluation of a miniaturised single-stage thermal modulator for comprehensive two-dimensional gas chromatography of petroleum contaminated soils.

    PubMed

    Jacobs, Matthew R; Edwards, Matthew; Górecki, Tadeusz; Nesterenko, Pavel N; Shellie, Robert A

    2016-09-01

    A novel miniaturised single-stage resistively heated thermal modulator was investigated as an alternative to cryogenic modulation for use in comprehensive two-dimensional gas chromatography (GC×GC). The single-stage thermal modulator described herein yielded average retention time relative standard deviations (RSD) of ≤0.2% RSD (first-dimension) and ≤3.4% RSD (second-dimension). The average peak widths generated by the modulator were 72±3ms, and the peak area precision was better than 5.3% RSD for a range of polar and non-polar test analytes. GC×GC analysis can be performed using this modulator without the requirement for cryogenic cooling or additional pressure control modules for flow modulation. The modulator and associated electronics are compact and amenable towards field analysis. The modulator was used for qualitative and quantitative characterisation of petroleum-contaminated soils derived from a sub-Antarctic research station at Macquarie Island. The limit of detection compared to standard 1D GC analysis was improved from 64 to 11mgkg(-1). An automated method of analysing and categorising samples using principal component analysis is presented.

  4. 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

  5. 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.

  6. Imperfection Insensitive Thin Shells

    NASA Astrophysics Data System (ADS)

    Ning, Xin

    The buckling of axially compressed cylindrical shells and externally pressurized spherical shells is extremely sensitive to even very small geometric imperfections. In practice this issue is addressed by either using overly conservative knockdown factors, while keeping perfect axial or spherical symmetry, or adding closely and equally spaced stiffeners on shell surface. The influence of imperfection-sensitivity is mitigated, but the shells designed from these approaches are either too heavy or very expensive and are still sensitive to imperfections. Despite their drawbacks, these approaches have been used for more than half a century. This thesis proposes a novel method to design imperfection-insensitive cylindrical shells subject to axial compression. Instead of following the classical paths, focused on axially symmetric or high-order rotationally symmetric cross-sections, the method in this thesis adopts optimal symmetry-breaking wavy cross-sections (wavy shells). The avoidance of imperfection sensitivity is achieved by searching with an evolutionary algorithm for smooth cross-sectional shapes that maximize the minimum among the buckling loads of geometrically perfect and imperfect wavy shells. It is found that the shells designed through this approach can achieve higher critical stresses and knockdown factors than any previously known monocoque cylindrical shells. It is also found that these shells have superior mass efficiency to almost all previously reported stiffened shells. Experimental studies on a design of composite wavy shell obtained through the proposed method are presented in this thesis. A method of making composite wavy shells and a photogrametry technique of measuring full-field geometric imperfections have been developed. Numerical predictions based on the measured geometric imperfections match remarkably well with the experiments. Experimental results confirm that the wavy shells are not sensitive to imperfections and can carry axial compression

  7. Single-particle spectral density of the unitary Fermi gas: Novel approach based on the operator product expansion, sum rules and the maximum entropy method

    SciTech Connect

    Gubler, Philipp; Yamamoto, Naoki; Hatsuda, Tetsuo; Nishida, Yusuke

    2015-05-15

    Making use of the operator product expansion, we derive a general class of sum rules for the imaginary part of the single-particle self-energy of the unitary Fermi gas. The sum rules are analyzed numerically with the help of the maximum entropy method, which allows us to extract the single-particle spectral density as a function of both energy and momentum. These spectral densities contain basic information on the properties of the unitary Fermi gas, such as the dispersion relation and the superfluid pairing gap, for which we obtain reasonable agreement with the available results based on quantum Monte-Carlo simulations.

  8. Ocean acidification alters the material properties of Mytilus edulis shells

    PubMed Central

    Fitzer, Susan C.; Zhu, Wenzhong; Tanner, K. Elizabeth; Phoenix, Vernon R.; Kamenos, Nicholas A.; Cusack, Maggie

    2015-01-01

    Ocean acidification (OA) and the resultant changing carbonate saturation states is threatening the formation of calcium carbonate shells and exoskeletons of marine organisms. The production of biominerals in such organisms relies on the availability of carbonate and the ability of the organism to biomineralize in changing environments. To understand how biomineralizers will respond to OA the common blue mussel, Mytilus edulis, was cultured at projected levels of pCO2 (380, 550, 750, 1000 µatm) and increased temperatures (ambient, ambient plus 2°C). Nanoindentation (a single mussel shell) and microhardness testing were used to assess the material properties of the shells. Young's modulus (E), hardness (H) and toughness (KIC) were measured in mussel shells grown in multiple stressor conditions. OA caused mussels to produce shell calcite that is stiffer (higher modulus of elasticity) and harder than shells grown in control conditions. The outer shell (calcite) is more brittle in OA conditions while the inner shell (aragonite) is softer and less stiff in shells grown under OA conditions. Combining increasing ocean pCO2 and temperatures as projected for future global ocean appears to reduce the impact of increasing pCO2 on the material properties of the mussel shell. OA may cause changes in shell material properties that could prove problematic under predation scenarios for the mussels; however, this may be partially mitigated by increasing temperature. PMID:25540244

  9. Ocean acidification alters the material properties of Mytilus edulis shells.

    PubMed

    Fitzer, Susan C; Zhu, Wenzhong; Tanner, K Elizabeth; Phoenix, Vernon R; Kamenos, Nicholas A; Cusack, Maggie

    2015-02-01

    Ocean acidification (OA) and the resultant changing carbonate saturation states is threatening the formation of calcium carbonate shells and exoskeletons of marine organisms. The production of biominerals in such organisms relies on the availability of carbonate and the ability of the organism to biomineralize in changing environments. To understand how biomineralizers will respond to OA the common blue mussel, Mytilus edulis, was cultured at projected levels of pCO2 (380, 550, 750, 1000 µatm) and increased temperatures (ambient, ambient plus 2°C). Nanoindentation (a single mussel shell) and microhardness testing were used to assess the material properties of the shells. Young's modulus (E), hardness (H) and toughness (KIC) were measured in mussel shells grown in multiple stressor conditions. OA caused mussels to produce shell calcite that is stiffer (higher modulus of elasticity) and harder than shells grown in control conditions. The outer shell (calcite) is more brittle in OA conditions while the inner shell (aragonite) is softer and less stiff in shells grown under OA conditions. Combining increasing ocean pCO2 and temperatures as projected for future global ocean appears to reduce the impact of increasing pCO2 on the material properties of the mussel shell. OA may cause changes in shell material properties that could prove problematic under predation scenarios for the mussels; however, this may be partially mitigated by increasing temperature.

  10. Enhancement of Thermoelectric Performance by Reducing Phonon Thermal Conductance in Multiple Core-shell Nanowires

    PubMed Central

    Zhou, Wu-Xing; Chen, Ke-Qiu

    2014-01-01

    The thermoelectric properties of multiple core-shell nanowires are investigated by using nonequilibrium Green's function method and molecular dynamics simulations. The results show that the thermoelectric performance of multiple core-shell NWs can be improved observably with the increase of shell number compared with the single component NWs due to the significant reduction of phonon thermal conductance. The ZT value of multiple core-shell NWs can reach three times greater than that of the single component GaSb NWs at room temperature. Moreover, the ZT values of both the core-shell NWs and single component NWs are increased with the increasing temperature, but the ZT value of core-shell NWs increases more slowly than that of single component NWs. These results show that the single component NWs is suitable as thermoelectric material at much high temperature, but the multiple core-shell NWs is more suitable as thermoelectric material at room temperature. PMID:25413874

  11. Method to produce large, uniform hollow spherical shells

    DOEpatents

    Hendricks, C.D.

    1983-09-26

    The invention is a method to produce large uniform hollow spherical shells by (1) forming uniform size drops of heat decomposable or vaporizable material, (2) evaporating the drops to form dried particles, (3) coating the dried particles with a layer of shell forming material and (4) heating the composite particles to melt the outer layer and to decompose or vaporize the inner particle to form an expanding inner gas bubble. The expanding gas bubble forms the molten outer layer into a shell of relatively large diameter. By cycling the temperature and pressure on the molten shell, nonuniformities in wall thickness can be reduced. The method of the invention is utilized to produce large uniform spherical shells, in the millimeter to centimeter diameter size range, from a variety of materials and of high quality, including sphericity, concentricity and surface smoothness, for use as laser fusion or other inertial confinement fusion targets as well as other applications.

  12. Gravitationally collapsing shells in (2+1) dimensions

    SciTech Connect

    Mann, Robert B.; Oh, John J.

    2006-12-15

    We study gravitationally collapsing models of pressureless dust, fluids with pressure, and the generalized Chaplygin gas (GCG) shell in (2+1)-dimensional spacetimes. Various collapse scenarios are investigated under a variety of the background configurations such as anti-de Sitter (AdS) black hole, de Sitter (dS) space, flat and AdS space with a conical deficit. As with the case of a disk of dust, we find that the collapse of a dust shell coincides with the Oppenheimer-Snyder type collapse to a black hole provided the initial density is sufficiently large. We also find - for all types of shell - that collapse to a naked singularity is possible under a broad variety of initial conditions. For shells with pressure this singularity can occur for a finite radius of the shell. We also find that GCG shells exhibit diverse collapse scenarios, which can be easily demonstrated by an effective potential analysis.

  13. Gas-Phase Synthesis of Singly and Multiply Charged Polyoxovanadate Anions Employing Electrospray Ionization and Collision Induced Dissociation

    SciTech Connect

    Al Hasan, Naila M.; Johnson, Grant E.; Laskin, Julia

    2013-07-02

    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

  14. A new double-tracer gas single-breath washout to assess early cystic fibrosis lung disease.

    PubMed

    Singer, Florian; Stern, Georgette; Thamrin, Cindy; Abbas, Chiara; Casaulta, Carmen; Frey, Urs; Latzin, Philipp

    2013-02-01

    In cystic fibrosis (CF), tests for ventilation inhomogeneity are sensitive but not established for clinical routine. We assessed feasibility of a new double-tracer gas single-breath washout (SBW) in school-aged children with CF and control subjects, and compared SBW between groups and with multiple-breath nitrogen washout (MBNW). Three SBW and MBNW were performed in 118 children (66 with CF) using a side-stream ultrasonic flowmeter setup. The double-tracer gas containing 5% sulfur hexafluoride and 26.3% helium was applied during one tidal breath. Outcomes were SBW phase III slope (SIII(DTG)), MBNW-derived lung clearance index (LCI), and indices of acinar (S(acin)) and conductive (S(cond)) ventilation inhomogeneity. SBW took significantly less time to perform than MBNW. SBW and MBNW were feasible in 109 (92.4%) and 98 (83.0%) children, respectively. SIII(DTG) differed between children with CF and controls, mean±sd was -456.7±492.8 and -88.4±129.1 mg·mol·L(-1), respectively. Abnormal SIII(DTG) was present in 36 (59%) children with CF. SIII(DTG) was associated with LCI (r= -0.58) and S(acin) (r= -0.58), but not with S(cond). In CF, steeply sloping SIII(DTG) potentially reflects ventilation inhomogeneity near the acinus entrance. This tidal SBW is a promising test to assess ventilation inhomogeneity in an easy and fast way. PMID:22599360

  15. Iridescence color of shells

    NASA Astrophysics Data System (ADS)

    Liu, Yan

    2002-06-01

    Some shells from both salt water and fresh water show the phenomenon of iridescence color. Pearls and mother-of-pearls also display this phenomenon. In the past, the cause of the iridescence color was attributed to interference. A scanning electron microscope (SEM) was used to study the surface structure of the shell of the mollusk Pinctada Margaritifera. There is a groove structure of reflection grating on the surface area in where the iridescence color appears. An optic experiment with a laser obtained a diffraction pattern produced by the reflection grating structure of the shell. The study led to a conclusion that the iridescence color of the shell is caused by diffraction. A SEM image of the shells of an abalone Haliotis Rufescens (red abalone) showed a statistically regularly arranged tile structure that serves as a two-dimensional grating. This grating structure causes the iridescence color of the shell of red abalone. The dominant color of the iridescence of shells is caused by the uneven grating efficiency in the visible wavelength range when a shell functions as a reflection grating. The wavelength of the dominant color should be at or near the wavelength of the maximum efficiency of the grating.

  16. Static cylindrical matter shells

    NASA Astrophysics Data System (ADS)

    Arık, Metin; Delice, Özgür

    2005-08-01

    Static cylindrical shells composed of massive particles arising from matching of two different Levi-Civita space-times are studied for the shell satisfying either an isotropic or an anisotropic equation of state. We find that these solutions satisfy the energy conditions for certain ranges of the parameters.

  17. WHAT IS THE SHELL AROUND R CORONAE BOREALIS?

    SciTech Connect

    Montiel, Edward J.; Clayton, Geoffrey C.; Marcello, Dominic C.; Lockman, Felix J. E-mail: gclayton@fenway.phys.lsu.edu E-mail: jlockman@nrao.edu

    2015-07-15

    The hydrogen-deficient, carbon-rich R Coronae Borealis (RCB) stars are known for being prolific producers of dust which causes their large iconic declines in brightness. Several RCB stars, including R Coronae Borealis (R CrB), itself, have large extended dust shells seen in the far-infrared. The origin of these shells is uncertain but they may give us clues to the evolution of the RCB stars. The shells could form in three possible ways. (1) They are fossil Planetary Nebula (PN) shells, which would exist if RCB stars are the result of a final, helium-shell flash, (2) they are material left over from a white-dwarf (WD) merger event which formed the RCB stars, or (3) they are material lost from the star during the RCB phase. Arecibo 21 cm observations establish an upper limit on the column density of H I in the R CrB shell implying a maximum shell mass of ≲0.3 M{sub ☉}. A low-mass fossil PN shell is still a possible source of the shell although it may not contain enough dust. The mass of gas lost during a WD merger event will not condense enough dust to produce the observed shell, assuming a reasonable gas-to-dust ratio. The third scenario where the shell around R CrB has been produced during the star’s RCB phase seems most likely to produce the observed mass of dust and the observed size of the shell. But this means that R CrB has been in its RCB phase for ∼10{sup 4} years.

  18. Experimental study of unsteady heat release in an unstable single element Lean Direct Injection (LDI) gas turbine combustor

    NASA Astrophysics Data System (ADS)

    Lakshmanan, Varun S.

    In an effort to curb emissions from gas turbine engines, many low emission engine concepts have been developed. Among the most promising of these is the LDI (Lean Direct Injection). These systems operate at relatively low equivalence ratios close to blowout and are prone to instabilities. Combustion instabilities can reduce the life of the combustor by causing large pressure fluctuations and enhanced heat release to the walls of the combustor and reduce the efficiency of the engines. The understanding of combustion instabilities is vital to the implementation of such systems. Combustion instabilities are studied in an self-excited single element gas turbine combustor that uses an LDI element for fuel injection at elevetaed chamber pressures. The LDI combustor uses a swirler to ensure mixing of the air and the fuel and expansion of the swirl through a pressure swirl venturi to create a swirl stabilized flame. This project aims to study the heat release modes that occur in the combustor through measurement of light emissions from the flame using photodiodes that are sensitive to wavelengths of light produced by the flame. These are used along with high frequency pressure transducers. The focus is on the flame behavior in the diverging section of the venturi where the swirl is expanded and the flame starts since optic access cannot be obtained in this section. The use of photodiodes also facilitates the study of hydrodynamic modes that occur in the combustor alongside the thermoacoustics. A section which could accommodate the photodiodes was designed and installed on the LDI test rig in the Gas Turbine Cell at Maurice J Zucrow Propulsion Labs at Purdue University. The combustor was tested with this section and dynamic data was obtained from the pressure transducers and the photodiodes for a range of inlet air temperatures and range of equivalence ratios for each inlet air temperature. The dominant instability modes in both sets of data were analyzed and are presented

  19. Nuclear shell evolution

    NASA Astrophysics Data System (ADS)

    Bentley, Ian

    2016-03-01

    The appearance and disappearance of nuclear shells and sub-shells has been at the forefront of recent nuclear theory and experimental efforts. This work extends a previously introduced method of structural analysis and applies it to protons in an attempt to provide a more complete understanding of shell structure in nuclei. Experimental observables including the mean square charge radius, as well as other spectroscopic and mass related quantities have been analyzed for shell structure features. A preliminary analysis using Nilsson coefficient fits of experimental quantities, such as odd mass spectra and B(E2) values, along isotopic chains will be discussed. The goal of this work is to provide a means of predicting shell structure far from stability. This work was supported by the National Science Foundation under Grants PHY1419765 and PHY0822648.

  20. Cohesive Elements for Shells

    NASA Technical Reports Server (NTRS)

    Davila, Carlos G.; Camanho, Pedro P.; Turon, Albert

    2007-01-01

    A cohesive element for shell analysis is presented. The element can be used to simulate the initiation and growth of delaminations between stacked, non-coincident layers of shell elements. The procedure to construct the element accounts for the thickness offset by applying the kinematic relations of shell deformation to transform the stiffness and internal force of a zero-thickness cohesive element such that interfacial continuity between the layers is enforced. The procedure is demonstrated by simulating the response and failure of the Mixed Mode Bending test and a skin-stiffener debond specimen. In addition, it is shown that stacks of shell elements can be used to create effective models to predict the inplane and delamination failure modes of thick components. The results indicate that simple shell models can retain many of the necessary predictive attributes of much more complex 3D models while providing the computational efficiency that is necessary for design.

  1. Atomic inner-shell transitions

    NASA Technical Reports Server (NTRS)

    Crasemann, B.; Chen, M. H.; Mark, H.

    1984-01-01

    Atomic inner-shell processes have quite different characteristics, in several important aspects, from processes in the optical regime. Energies are large, e.g., the 1s binding energy reaches 100 keV at Z = 87; relativistic and quantum-electrodynamic effects therefore are strong. Radiationless transitions vastly dominate over photon emission in most cases. Isolated inner-shell vacancies have pronounced single-particle character, with correlations generally contributing only approximately 1 eV to the 1s and 2p binding energies; the structure of such systems is thus well tractable by independent-particle self-consistent-field atomic models. For systems containing multiple deep inner-shell vacancies, or for highly stripped ions, the importance of relativistic intermediate coupling and configuration interaction becomes pronounced. Cancellation of the Coulomb interaction can lead to strong manifestations of the Breit interaction in such phenomena as multiplet splitting and hypersatellite X-ray shifts. Unique opportunities arise for the test of theory.

  2. Optical Properties of Anisotropic Core-Shell Pyramidal Particles

    PubMed Central

    Sweeney, Christina M.; Hasan, Warefta; Nehl, Colleen L.; Odom, Teri W.

    2009-01-01

    This paper describes an approach to fabricate anisotropic core-shell particles by assembling dielectric beads within fabricated noble metal pyramidal structures. Particles with gold (Au) shells and different dielectric cores were generated, and their optical properties were characterized by single particle spectroscopy. Because of their unique geometry, these particles exhibit multiple plasmon resonances from visible to near-IR wavelengths. PMID:19290590

  3. Single-Shell Tank Leak Integrity Summary

    SciTech Connect

    Harlow, D. G.; Girardot, C. L.; Venetz, T. J.

    2015-03-26

    This document summarizes and evaluates the information in the Hanford Tri-Party Agreement Interim Milestone M-045-91F Targets completed between 2010 and 2015. 1) Common factors of SST liner failures (M-045-91F-T02), 2) the feasibility of testing for ionic conductivity between the inside and outside of SSTs (M-045-91F-T03, and 3) the causes, locations, and rates of leaks from leaking SSTs (M-045-91F-T04).

  4. Alternative Inspection Methods for Single Shell Tanks

    SciTech Connect

    Peters, Timothy J.; Alzheimer, James M.; Hurley, David E.

    2010-01-19

    This document was prepared to provide evaluations and recommendations regarding nondestructive evaluation methods that might be used to determine cracks and bowing in the ceiling of waste storage tanks on the Hanford site. The goal was to determine cracks as small as 1/16 in. wide in the ceiling, and bowing as small as 0.25 in. This report describes digital video camera methods that can be used to detect a crack in the ceiling of the dome, and methods for determining the surface topography of the ceiling in the waste storage tanks to detect localized movements in the surface. A literature search, combined with laboratory testing, comprised this study.

  5. Borehole Data Package for Two RCRA Wells 299-W11-25B and 299-W11-46 at Single-Shell Tank Waste Management Area T, Hanford Site, Washington

    SciTech Connect

    Horton, Duane G.; Chamness, Mickie A.

    2006-04-17

    One new Resource Conservation and Recovery Act (RCRA) groundwater monitoring and assessment well was installed at single-shell tank Waste Management Area (WMA) T in calendar year 2005 in partial fulfillment of commitments for well installations proposed in Hanford Federal Facility Agreement and Consent Order, Milestone M-24-57 (2004). The need for increased monitoring capability at this WMA was identified during a data quality objectives process for establishing a RCRA/Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)/Atomic Energy Act (AEA) integrated 200 West and 200 East Area Groundwater Monitoring Network. The initial borehole, 299-W11-25B, was located about 20 ft from existing downgradient well 299 W11-39. The specific objective for the borehole was to determine the vertical distribution of contaminants in the unconfined aquifer at the northeast corner of WMA T. The permanent casing in borehole 299-W11-25B was damaged beyond repair during well construction and replacement borehole, 299-W11-46, was drilled about 10 ft from borehole 299-W11-25B (Figure 1). Borehole 299-W11-46 was completed as a RCRA monitoring well. This document provides a compilation of all available geologic data, geophysical logs, hydrogeologic data and well information obtained during drilling, well construction, well development, pump installation, groundwater sampling and analysis activities, and preliminary results of slug tests associated with wells 299-W11-25B and 299-W11-46. Appendix A contains geologists logs, Well Construction Summary Reports, Well Summary Sheets (as-built diagrams), and Well Development and Testing Data sheets. Appendix B contains the results of chemical analysis of groundwater samples. Appendix C contains complete spectral gamma-ray logs and borehole deviation surveys and Appendix D contains initial results of slug tests. The non-conformance report for borehole 299-W11-46 is provided in Appendix E.

  6. Stability analysis of thin-shell wormholes from charged black string

    SciTech Connect

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

    2013-04-01

    In this paper, we construct thin-shell wormholes from charged black string through cut and paste procedure and investigate its stability. We assume modified generalized Chaplygin gas as a dark energy fluid (exotic matter) present in the thin layer of matter-shell. The stability of these constructed thin-shell wormholes is investigated in the scenario of linear perturbations. We conclude that static stable as well as unstable configurations are possible for cylindrical thin-shell wormholes.

  7. Application of noncatalytic gas-solid reactions for a single pellet of changing size to the modeling of fluidized-bed combustion of coal char containing sulfur

    SciTech Connect

    Rehmat, A.; Saxena, S.C.; Land, R.H.

    1980-09-01

    A mechanistic model is developed for coal char combustion, with sulfur retention by limestone or dolomite sorbent, in a gas fluidized bed employing noncatalytic single pellet gas-solid reactions. The shrinking core model is employed to describe the kinetics of chemical reactions taking place on a single pellet; changes in pellet size as the reaction proceeds are considered. The solids are assumed to be in back-mix condition whereas the gas flow is regarded to be in plug flow. Most char combustion occurs near the gas distributor plate (at the bottom of the bed), where the bubbles are small and consequently the mass transfer rate is high. For such a case, the analysis is considerably simplified by ignoring the bubble phase since it plays an insignificant role in the overall rate of carbon conversion. Bubble-free operation is also encounterd in the turbulent regime, where the gas flow is quite high and classical bubbles do not exist. Formulation of the model includes setting up heat and mass balance equations pertaining to a single particle (1) exposed to a varying reactant concentration along the height of the bed and (2) whose size changes during reaction. These equations are then solved numerically to account for particles of all sizes in the bed in obtaining the overall carbon conversion efficiency and resultant sulfur retention. In particular, the influence on sorbent requirement of several fluid-bed variables such as oxygen concentration profile, particle size, reaction rate for sulfation reaction, and suflur adsorption efficiency are examined.

  8. Fuel cell performance of palladium-platinum core-shell electrocatalysts synthesized in gram-scale batches

    DOE PAGES

    Khateeb, Siddique; Su, Dong; Guerreo, Sandra; Darling, Robert M.; Protsailo, Lesia V.; Shao, Minhua

    2016-05-03

    This article presents the performance of palladium-platinum core-shell catalysts (Pt/Pd/C) for oxygen reduction synthesized in gram-scale batches in both liquid cells and polymer-electrolyte membrane fuel cells. Core-shell catalyst synthesis and characterization, ink fabrication, and cell assembly details are discussed. The Pt mass activity of the Pt/Pd core-shell catalyst was 0.95 A mg–1 at 0.9 V measured in liquid cells (0.1 M HClO4), which was 4.8 times higher than a commercial Pt/C catalyst. The performances of Pt/Pd/C and Pt/C in large single cells (315 cm2) were assessed under various operating conditions. The core-shell catalyst showed consistently higher performance than commercial Pt/Cmore » in fuel cell testing. A 20–60 mV improvement across the whole current density range was observed on air. Sensitivities to temperature, humidity, and gas composition were also investigated and the core-shell catalyst showed a consistent benefit over Pt under all conditions. However, the 4.8 times activity enhancement predicated by liquid cell measurements was not fully realized in fuel cells.« less

  9. Synthesis of single-walled carbon nanotubes from Pd catalysts by gas source method using ethanol in high vacuum

    NASA Astrophysics Data System (ADS)

    Kozawa, Akinari; Saida, Takahiro; Naritsuka, Shigeya; Maruyama, Takahiro

    2016-01-01

    We carried out single-walled carbon nanotube (SWCNT) growth at 600 °C using Pd catalysts by the alcohol gas source method. When Pd catalysts deposited on SiO2/Si substrates were used, the G band in the Raman spectra was broad and weak RBM peaks were observed at ethanol pressures between 1 × 10-3 and 1 × 10-1 Pa. On the other hand, using Al2Ox buffer layers, a sharp G band with a shoulder peak (G- peak) and several radial breathing mode (RBM) peaks were observed, which indicates the growth of SWCNTs. Scanning electron microscopy (SEM) observation showed that dense web like SWCNTs were formed, and the diameters of SWCNTs estimated from the wavenumbers of RBM peaks were 1.3-2.9 nm, which were larger than those from Pt catalysts. Transmission electron microscopy (TEM) observation showed that the larger migration distance of Pd caused an enlargement of catalyst particle sizes, resulting in the larger diameters of SWCNTs from Pd catalysts.

  10. [Single-handed helical framework material [{Cu(sala)}n] incorporated peramylated β-cyclodextrin for improving gas chromatography enantioseparation].

    PubMed

    Xie, Shengming; Liu, Hong; Yang, Jiangrong; Ai, Ping; Yuan, Liming

    2016-01-01

    Metal-organic frameworks (MOFs) as a new generation of functional molecular materials, have broad application prospects in enantioselective catalysis and chiral separation areas due to their unusual properties, such as high surface area, rich topologies, permanent microporous, availability of outer-surface modification and so on. A single-handed helical three-dimensional metal-organic framework material [{Cu(sala)}n] (H2sala=N-(2-hydroxybenzyl)-L-alanine) was incorporated with peramylated β-cyclodextrin for the preparation of novel capillary gas chromatography stationary phase. To investigate whether the use of a chiral MOF can enhance enantioseparation on peramylated β-cyclodextrin, three chiral columns were fabricated using different stationary phases for comparison, including column A ([{Cu (sala)}n]), column B (peramylated β-cyclodextrin) and column C ([{Cu(sala)}n]+peramylated β-cyclodextrin). The results of comparing the resolving abilities of the three columns for the same chiral compounds demonstrated that column C showed better enantioselectivity and higher resolution. The use of MOF [{Cu(sala)}n] can improve enantioseparation on peramylated β-cyclodextrin. PMID:27319175

  11. Gas-phase production of single-walled carbon nanotubes from carbon monoxide: a review of the hipco process

    NASA Technical Reports Server (NTRS)

    Nikolaev, Pavel

    2004-01-01

    The latest process for producing large quantities of single-walled carbon nanotubes (SWNTs) to emerge from the Rice University, dubbed HiPco, is living up to its promise. The current production rates approach 450 mg/h (or 10 g/day), and nanotubes typically have no more than 7 mol % of iron impurities. Second-generation HiPco apparatus can run continuously for 7-10 days at a time. In the HiPco process nanotubes grow in high-pressure, high-temperature flowing CO on catalytic clusters of iron. Catalyst is formed in situ by thermal decomposition of iron pentacarbonyl, which is delivered intact within a cold CO flow and then rapidly mixed with hot CO in the reaction zone. Upon heating, the Fe(CO)5 decomposes into atoms that condense into larger clusters. SWNTs nucleate and grow on these particles in the gas phase via CO disproportionation: CO + CO --> CO2 + C (SWNT), catalyzed by the Fe surface. The concentration of CO2 produced in this reaction is equal to that of carbon and can therefore serve as a useful real-time feedback parameter. It was used to study and optimize SWNT production as a function of temperature, pressure, and Fe(CO)5 concentration. The results of the parametric study are in agreement with current understanding of the nanotube formation mechanism.

  12. Estimation of bias with the single-zone assumption in measurement of residential air exchange using the perfluorocarbon tracer gas method

    PubMed Central

    Van Ryswyk, K; Wallace, L; Fugler, D; MacNeill, M; Héroux, M È; Gibson, M D; Guernsey, J R; Kindzierski, W; Wheeler, A J

    2015-01-01

    Residential air exchange rates (AERs) are vital in understanding the temporal and spatial drivers of indoor air quality (IAQ). Several methods to quantify AERs have been used in IAQ research, often with the assumption that the home is a single, well-mixed air zone. Since 2005, Health Canada has conducted IAQ studies across Canada in which AERs were measured using the perfluorocarbon tracer (PFT) gas method. Emitters and detectors of a single PFT gas were placed on the main floor to estimate a single-zone AER (AER1z). In three of these studies, a second set of emitters and detectors were deployed in the basement or second floor in approximately 10% of homes for a two-zone AER estimate (AER2z). In total, 287 daily pairs of AER2z and AER1z estimates were made from 35 homes across three cities. In 87% of the cases, AER2z was higher than AER1z. Overall, the AER1z estimates underestimated AER2z by approximately 16% (IQR: 5–32%). This underestimate occurred in all cities and seasons and varied in magnitude seasonally, between homes, and daily, indicating that when measuring residential air exchange using a single PFT gas, the assumption of a single well-mixed air zone very likely results in an under prediction of the AER. PMID:25399878

  13. Impact of the etching gas on vertically oriented single wall and few walled carbon nanotubes by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Gohier, A.; Minea, T. M.; Djouadi, M. A.; Granier, A.

    2007-03-01

    Vertically oriented single wall nanotubes (SWNTs) and few walled nanotubes (FWNTs) have been grown by electronic cyclotron resonance plasma enhanced chemical vapor deposition (PECVD) on silica flat substrates. The impact of the plasma parameters on SWNT and FWNT growth has been investigated using two different etching gas mixtures, namely, C2H2/NH3 and C2H2/H2 with various ratios and applied bias voltages. Kinetic studies are also proposed in order to describe the FWNT growth mechanism by plasma techniques. A key role played by the reactive gas (NH3 and H2) is observed in the PECVD process, contrary to multiwalled nanotube growth. It is demonstrated that the balance between FWNT growth versus FWNT etching can be widely modulated by varying the gas mixture and bias voltage. It is shown that the use of hydrogen for hydrocarbon gas dilution restricts the destruction of SWNT and FWNT by the plasma species (ions and radicals).

  14. Waltzing route toward double-helix formation in cholesteric shells

    NASA Astrophysics Data System (ADS)

    Darmon, Alexandre; Benzaquen, Michael; Seč, David; Čopar, Simon; Dauchot, Olivier; Lopez-Leon, Teresa

    2016-08-01

    Liquid crystals, when confined to a spherical shell, offer fascinating possibilities for producing artificial mesoscopic atoms, which could then self-assemble into materials structured at a nanoscale, such as photonic crystals or metamaterials. The spherical curvature of the shell imposes topological constraints in the molecular ordering of the liquid crystal, resulting in the formation of defects. Controlling the number of defects, that is, the shell valency, and their positions, is a key success factor for the realization of those materials. Liquid crystals with helical cholesteric order offer a promising, yet unexplored way of controlling the shell defect configuration. In this paper, we study cholesteric shells with monovalent and bivalent defect configurations. By bringing together experiments and numerical simulations, we show that the defects appearing in these two configurations have a complex inner structure, as recently reported for simulated droplets. Bivalent shells possess two highly structured defects, which are composed of a number of smaller defect rings that pile up through the shell. Monovalent shells have a single radial defect, which is composed of two nonsingular defect lines that wind around each other in a double-helix structure. The stability of the bivalent configuration against the monovalent one is controlled by c = h/p, where h is the shell thickness and p the cholesteric helical pitch. By playing with the shell geometry, we can trigger the transition between the two configurations. This transition involves a fascinating waltz dynamics, where the two defects come closer while turning around each other.

  15. Waltzing route toward double-helix formation in cholesteric shells.

    PubMed

    Darmon, Alexandre; Benzaquen, Michael; Seč, David; Čopar, Simon; Dauchot, Olivier; Lopez-Leon, Teresa

    2016-08-23

    Liquid crystals, when confined to a spherical shell, offer fascinating possibilities for producing artificial mesoscopic atoms, which could then self-assemble into materials structured at a nanoscale, such as photonic crystals or metamaterials. The spherical curvature of the shell imposes topological constraints in the molecular ordering of the liquid crystal, resulting in the formation of defects. Controlling the number of defects, that is, the shell valency, and their positions, is a key success factor for the realization of those materials. Liquid crystals with helical cholesteric order offer a promising, yet unexplored way of controlling the shell defect configuration. In this paper, we study cholesteric shells with monovalent and bivalent defect configurations. By bringing together experiments and numerical simulations, we show that the defects appearing in these two configurations have a complex inner structure, as recently reported for simulated droplets. Bivalent shells possess two highly structured defects, which are composed of a number of smaller defect rings that pile up through the shell. Monovalent shells have a single radial defect, which is composed of two nonsingular defect lines that wind around each other in a double-helix structure. The stability of the bivalent configuration against the monovalent one is controlled by c = h/p, where h is the shell thickness and p the cholesteric helical pitch. By playing with the shell geometry, we can trigger the transition between the two configurations. This transition involves a fascinating waltz dynamics, where the two defects come closer while turning around each other. PMID:27493221

  16. Locally adaptive method to define coordination shell

    NASA Astrophysics Data System (ADS)

    Higham, Jonathan; Henchman, Richard H.

    2016-08-01

    An algorithm is presented to define a particle's coordination shell for any collection of particles. It requires only the particles' positions and no pre-existing knowledge or parameters beyond those already in the force field. A particle's shell is taken to be all particles that are not blocked by any other particle and not further away than a blocked particle. Because blocking is based on two distances and an angle for triplets of particles, it is called the relative angular distance (RAD) algorithm. RAD is applied to Lennard-Jones particles in molecular dynamics simulations of crystalline, liquid, and gaseous phases at various temperatures and densities. RAD coordination shells agree well with those from a cut-off in the radial distribution function for the crystals and liquids and are slightly higher for the gas.

  17. Locally adaptive method to define coordination shell.

    PubMed

    Higham, Jonathan; Henchman, Richard H

    2016-08-28

    An algorithm is presented to define a particle's coordination shell for any collection of particles. It requires only the particles' positions and no pre-existing knowledge or parameters beyond those already in the force field. A particle's shell is taken to be all particles that are not blocked by any other particle and not further away than a blocked particle. Because blocking is based on two distances and an angle for triplets of particles, it is called the relative angular distance (RAD) algorithm. RAD is applied to Lennard-Jones particles in molecular dynamics simulations of crystalline, liquid, and gaseous phases at various temperatures and densities. RAD coordination shells agree well with those from a cut-off in the radial distribution function for the crystals and liquids and are slightly higher for the gas. PMID:27586905

  18. Failure of Viral Shells

    NASA Astrophysics Data System (ADS)

    Klug, William S.; Bruinsma, Robijn F.; Michel, Jean-Philippe; Knobler, Charles M.; Ivanovska, Irena L.; Schmidt, Christoph F.; Wuite, Gijs J. L.

    2006-12-01

    We report a combined theoretical and experimental study of the structural failure of viral shells under mechanical stress. We find that discontinuities in the force-indentation curve associated with failure should appear when the so-called Föppl von Kármán (FvK) number exceeds a critical value. A nanoindentation study of a viral shell subject to a soft-mode instability, where the stiffness of the shell decreases with increasing pH, confirms the predicted onset of failure as a function of the FvK number.

  19. Buffer-Gas Cooling of a Single Ion in a Multipole Radio Frequency Trap Beyond the Critical Mass Ratio

    NASA Astrophysics Data System (ADS)

    Höltkemeier, Bastian; Weckesser, Pascal; López-Carrera, Henry; Weidemüller, Matthias

    2016-06-01

    We theoretically investigate the dynamics of a trapped ion immersed in a spatially localized buffer gas. For a homogeneous buffer gas, the ion's energy distribution reaches a stable equilibrium only if the mass of the buffer gas atoms is below a critical value. This limitation can be overcome by using multipole traps in combination with a spatially confined buffer gas. Using a generalized model for elastic collisions of the ion with the buffer-gas atoms, the ion's energy distribution is numerically determined for arbitrary buffer-gas distributions and trap parameters. Three regimes characterized by the respective analytic form of the ion's equilibrium energy distribution are found. Final ion temperatures down to the millikelvin regime can be achieved by adiabatically decreasing the spatial extension of the buffer gas and the effective ion trap depth (forced sympathetic cooling).

  20. Elastic platonic shells.

    PubMed

    Yong, Ee Hou; Nelson, David R; Mahadevan, L

    2013-10-25

    On microscopic scales, the crystallinity of flexible tethered or cross-linked membranes determines their mechanical response. We show that by controlling the type, number, and distribution of defects on a spherical elastic shell, it is possible to direct the morphology of these structures. Our numerical simulations show that by deflating a crystalline shell with defects, we can create elastic shell analogs of the classical platonic solids. These morphologies arise via a sharp buckling transition from the sphere which is strongly hysteretic in loading or unloading. We construct a minimal Landau theory for the transition using quadratic and cubic invariants of the spherical harmonic modes. Our approach suggests methods to engineer shape into soft spherical shells using a frozen defect topology.