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Sample records for 241-sy-101 surface level

  1. Process control plan for tank 241-SY-101 surface level rise remediation

    SciTech Connect

    ESTEY, S.D.

    1999-06-29

    The tank 241-SY-101 transfer system was conceived and designed to address the immediate needs presented by rapidly changing waste conditions in tank 241-SY-101. Within the past year or so, the waste in this tank has exhibited unexpected behavior in the form of rapidly increasing crust growth. The Process Control Plan (PCP), HNF-4264, was written to translate high-level guidance and regulatory criteria and express it in terms of operating instructions for the waste transfer system. These controls include: (1) Tank Farm Operations Administrative Controls developed in response to DOE-ORP direction reg,arding supplemental controls placed upon tank 241-SY-101 surface level rise remediation activities specifically involving waste transfer activities. (2) Authorization Basis controls (Basis for Interim Operation (BIO)/Technical Safety Requirements (TSRs)) and supplemental DOE direction. (3) Environmental, Industrial Hygiene and Safety controls. (4) Operating Specification Document (OSD) controls. (5) Good operating practices. Included in the document are descriptions of tank conditions, waste conditions, major equipment, and a high-level overview of the system and the line-ups in which it operates. Primarily, the PCP addresses how the waste transfer will be managed, defining the monitoring and control methods including material balances to determine the progress and to define completion criteria for the transfer. The actual plant modifications and waste transfer will be authorized and controlled by plant procedures.

  2. Process Control Plan for Tank 241-SY-101 Surface Level Rise Remediation

    SciTech Connect

    ESTEY, S.D.

    1999-09-28

    The tank 241-SY-101 transfer system was conceived and designed to address the immediate needs presented by rapidly changing waste conditions in tank 241-SY-101. Within the last year or so, the waste in this tank has exhibited unexpected behavior (Rassat et al. 1999) in the form of rapidly increasing crust growth. This growth has been brought about by a rapidly increasing rate of gas entrapment within the crust. It has been conceived that the lack of crust agitation beginning upon the advent of mixer pump operations may have set-up a more consolidated, gas impermeable barrier when compared to a crust regularly broken up by the prior buoyant displacement events within the tank. As a result, a series of level-growth remediation activities have been developed for tank 241-SY-101. The initial activities are also known as near-term crust mitigation. The first activity of near-term mitigation is to perform the small transfer of convective waste from tank 241-SY-101 into tank 241-SY-102. A 100 kgal transfer represents about a 10% volume reduction allowing a 10% water in-tank dilution. Current thinking holds that this should be enough to dissolve nitrite solids in the crust and perhaps largely eliminate gas retention problem in the crust (Raymond 1999).

  3. Process Control Plan for Tank 241-SY-101 Surface Level Rise Remediation

    SciTech Connect

    ESTEY, S.D.

    1999-11-01

    The tank 241-SY-101 transfer system was conceived and designed to address the immediate needs presented by rapidly changing waste conditions in tank 241-SY-101. Within approximately the last year, the waste in this tank has exhibited unexpected behavior (Rassat et al. 1999) in the form of rapidly increasing crust growth. This growth has been brought about by a rapidly increasing rate of gas entrapment within the crust. It has been conceived that the lack of crust agitation beginning upon the advent of mixer pump operations may have set-up a more consolidated, gas impermeable barrier when compared to a crust regularly broken up by the prior buoyant displacement events within the tank. The interim goals of the project are to: (1) protect the mixer pump operability (2) begin releasing gas from the crust, and (3) begin dissolving the crust and solids in the slurry layer. The final goals of the project (Final State) are to solve both the level growth and BD-GRE safety issues in this tank by achieving a condition of the waste such that no active measures are required to safely store the waste, i.e., crust and non convective layer are mostly dissolved, and therefore the mixer pump will no longer be needed to prevent BD-GREs in excess of 100% LFL. Transfers (which are designed to create space in the tank) and dilution (which will dissolve the solids) will accomplish this. Dissolution of solids will result in a release of gas retained by those solids and remove that volume of solids as a future retention site.

  4. Historical trends in tank 241-SY-101 waste temperatures and levels

    SciTech Connect

    Antoniak, Z.I.

    1993-09-01

    The gas release and fluctuating level of the waste in tank 241-SY-101 have prompted more detailed interest in its historical behavior, in hopes of achieving a better understanding of its current status. To examine the historical behavior, essentially all of the tank waste temperature and level data record has been retrieved, examined, and plotted in various ways. To aid in interpreting the data, the depth of the non-convective waste layer was estimated by using a least-squares Chebyshev approximation to the temperatures. This report documents the retrieval critical examination, and graphic presentation of 241-SY-101 temperature and waste level histories. The graphic presentations clearly indicate a tank cooling trend that has become precipitous since late 1991. The plots also clearly show the decreasing frequency of waste gas release events, increasing height of the non-convective layer, and larger level drops per event.

  5. Level sensor replacement/sampling of Tank 241-SY-101 at the Hanford Site

    SciTech Connect

    Not Available

    1990-01-01

    The US Department of Energy (DOE) is responsible for management and storage of waste accumulated from the processing of defense reactor irradiated fuels for plutonium recovery at the Hanford Site. DOE is proposing to remove three level detectors from Tank 241-SY-101 and analyze the waste that is presently encrusted on the detectors. The proposed sampling is less intrusive than core sampling and will provide data regarding characterization of the crust to support future core sampling. The purpose of this environmental assessment (EA) is to provide information about the proposed action such that a decision can be made on whether a Finding of No Significant Impact should be issued or an environmental impact statement should be prepared. Therefore, this EA evaluates the proposed action and the no action alternative, in keeping with requirements of the National Environmental Policy Act of 1969 (NEPA) and regulations of the Council on Environmental Quality, Title 40, Code of Federal Regulations, parts 1500--1508. 6 refs.

  6. Probabilistic safety assessment for Hanford high-level waste tank 241-SY-101

    SciTech Connect

    MacFarlane, D.R.; Bott, T.F.; Brown, L.F.; Stack, D.W.; Kindinger, J.; Deremer, R.K.; Medhekar, S.R.; Mikschl, T.J.

    1994-05-01

    Los Alamos National Laboratory (Los Alamos) is performing a comprehensive probabilistic safety assessment (PSA), which will include consideration of external events for the 18 tank farms at the Hanford Site. This effort is sponsored by the Department of Energy (DOE/EM, EM-36). Even though the methodology described herein will be applied to the entire tank farm, this report focuses only on the risk from the weapons-production wastes stored in tank number 241-SY-101, commonly known as Tank 101-SY, as configured in December 1992. This tank, which periodically releases ({open_quotes}burps{close_quotes}) a gaseous mixture of hydrogen, nitrous oxide, ammonia, and nitrogen, was analyzed first because of public safety concerns associated with the potential for release of radioactive tank contents should this gas mixture be ignited during one of the burps. In an effort to mitigate the burping phenomenon, an experiment is being conducted in which a large pump has been inserted into the tank to determine if pump-induced circulation of the tank contents will promote a slow, controlled release of the gases. At the Hanford Site there are 177 underground tanks in 18 separate tank farms containing accumulated liquid/sludge/salt cake radioactive wastes from 50 yr of weapons materials production activities. The total waste volume is about 60 million gal., which contains approximately 120 million Ci of radioactivity.

  7. Engineering task plan for determining the interstitial liquid level in tank 241-SY-101 utilizing a neutron probe in the multifunction instrument tree

    SciTech Connect

    CANNON, N.S.

    1999-02-23

    This plan outlines the steps to be taken to modify existing neutron/gamma probe designs to allow insertion of these probes into the multifunction instrument trees (MITs) at tank 241-SY-101. The objective is to locate and track this tank's Interstitial Liquid Level (ILL). This plan provides scope, schedule, and cost estimates to achieve this objective, and assigns individual organizational responsibilities to carry out this task.

  8. Status of tank 241-SY-101 data analyses

    SciTech Connect

    Anantatmula, R.P.

    1992-09-01

    The Waste Tank Flammable Gas Stabilization Program was established in 1990 to provide for resolution of a major safety issue identified for 23 of the high-level waste tanks at the Hanford Site. The safety issue involves the production, accumulation, and periodic release from these tanks of flammable gases in concentrations exceeding the lower flammability limits. This document deals primarily with tank 241-SY-101 from the SY Tank Farm. The flammable gas condition has existed for this tank since the tank was first filled in the time period from 1977 to 1980. During a general review of waste tank chemical stability in 1988--1989, this situation was re-examined and, in March 1990, the condition was declared to be an unreviewed safety question. Tank 241-SY-101 was placed under special operating restrictions, and a program of investigation was begun to evaluate the condition and determine appropriate courses of action. This report summarizes the data that have become available on tank 241-SY-101 since it was declared as an unreviewed safety question and updates the information reported in an earlier document (WHC-EP-0517). The report provides a technical basis for use in the evaluation of safety risks of the tank and subsequent resolution of the unreviewed safety question.

  9. Jet mixer pump testing in Hanford Tank 241-SY-101

    SciTech Connect

    Stewart, C.W.

    1994-11-01

    A mixer pump was found effective in controlling and possibly eliminating large episodic flammable gas releases from Hanford Tank 241-SY-101. A gas release event (GRE) is initiated when the gas-bearing sludge layer accumulates sufficient gas to become buoyant. The buoyant sludge pulls free from the surrounding material and rises through the surface crust releasing the trapped gas to the dome space. Mixer pump operation is intended to keep enough of the gas-generating material in suspension so that it releases gas continuously instead of periodically in large, potentially dangerous GREs. A mixer pump was installed in the tank on July 3, 1993, seven days after a typical GRE that met the safety criteria for pump installation. Because nozzle plugging did occur, bump speed and duration were increased, eventually arriving at the accepted five-minute period at 1000 rpm on July 26. There has been no nozzle plugging since. Bumping was initially performed twice daily through mid-August and once daily until the start of Phase B testing. By the end of Phase B, thrice-weekly bumping during non-testing periods became the rule. The jets were aimed into previously undisturbed material and gas release induced by the pump increased immediately. In November, the pump was indexed progressively around the entire tank in 30{degrees} steps. This steadily released a large quantity of retained gas at each position and reduced the waste level to 400 inches, the minimum level in many years. By December, the jets had apparently excavated most of the gas-bearing sludge within reach, because only modest gas releases and essentially no level change occurred after pump operation. For the rest of Phase B testing, there were no large gas releases that would suggest a large volume of unmixed waste. The two thermocouple trees showed a uniform vertical temperature profile. In the month following Phase B, minimal pump operation apparently maintained most of the mixing achieved during testing.

  10. Jet mixer pump testing in Hanford tank 241-SY-101

    SciTech Connect

    Stewart, C.W.

    1994-12-31

    A mixer pump was found effective in controlling and possibly eliminating large flammable gas releases from Hanford Tank 241-SY-101. A gas release event (GRE) is initiated when gas-bearing sludge accumulates sufficient gas to become buoyant. The buoyant sludge pulls free from the surrounding material and rises to the surface releasing the trapped gas. Mixer pump operation is intended to keep gas-generating material in suspension so that it releases gas continuously instead of periodically in large, potentially dangerous GREs. A mixer pump was installed July 3, 1993, 7 days after a typical GRE. The initial pump operation in phase-A testing was extremely gentle, beginning with a series of daily pump {open_quotes}bumps{close_quotes} intended to keep the pump nozzles clear. Because nozzle plugging did occur, bump speed and duration were increased, eventually arriving at the accepted 5-min period at 1000 rpm on July 26. There has been no nozzle plugging since. Bumping was initially performed twice daily through mid-August and once daily until the start of phase-B testing. By the end of phase B, thrice-weekly bumping became the rule.

  11. Hazard evaluation for transfer of waste from tank 241-SY-101 to tank 241-SY-102

    SciTech Connect

    SHULTZ, M.V.

    1999-04-05

    Tank 241-SY-101 waste level growth is an emergent, high priority issue. The purpose of this document is to record the hazards evaluation process and document potential hazardous conditions that could lead to the release of radiological and toxicological material from the proposed transfer of a limited quantity (approximately 100,000 gallons) of waste from Tank 241-SY-101 to Tank 241-SY-102. The results of the hazards evaluation were compared to the current Tank Waste Remediation System (TWRS) Basis for Interim Operation (HNF-SD-WM-BIO-001, 1998, Revision 1) to identify any hazardous conditions where Authorization Basis (AB) controls may not be sufficient or may not exist. Comparison to LA-UR-92-3196, A Safety Assessment for Proposed Pump Mixing Operations to Mitigate Episodic Gas Releases in Tank 241-SY-101, was also made in the case of transfer pump removal activities. Revision 1 of this document deletes hazardous conditions no longer applicable to the current waste transfer design and incorporates hazardous conditions related to the use of an above ground pump pit and overground transfer line. This document is not part of the AB and is not a vehicle for requesting authorization of the activity; it is only intended to provide information about the hazardous conditions associated with this activity. The AB Control Decision process will be used to determine the adequacy of controls and whether the proposed activity is within the AB. This hazard evaluation does not constitute an accident analysis.

  12. Operability test procedure [Tank] 241-SY-101 equipment removal system

    SciTech Connect

    Mast, J.C.

    1994-12-08

    The 241-SY-101 equipment removal system (ERS) consists of components, equipment, instrumentation and procedures that will provide the means to disconnect, retrieve, contain, load and transport the Mitigation Pump Assembly (MPA) from waste Tank 241-SY-101 to the Central Waste Complex (CWC). The Operability Test Procedure (OTP) will test the interfaces between ERS components and will rehearse the procedure for MPA removal and transportation to the extent they can be mocked-up at the CTF (Cold Test Facility). At the conclusion of the OTP, the ERS components and equipment will be removed from the CTF, entered into the Component Based Recall System (CBRS), and stored until needed for actual MPA removal and transportation.

  13. Quarterly review of 241-SY-101 mixer pump data: October - December, 1998

    SciTech Connect

    CONNER, J.M.

    1999-05-11

    This report presents data obtained on 241-SY-101 pump performance. The period covered is October 1 through December 31, 1998. During the quarter: (1) There was an indication of a 7.0-inch increase in the waste level at riser lA, and an average growth rate of 0.076 inches per day. (2) There was an indication of a 2.3-inch increase in the waste level at riser 1C. This riser was flushed with water several times, which would lower the level of the crust at this location. (3) Gases continued to be released at less than the pre-pump installation baseline rate, indicating a decrease in the gas generation rate, or an increase in gas retention, or both. The release rate was about 60 percent of the rate in the previous few quarters, and only 44 percent of the pre-pump release rate. (4) There was no change in the parameters that monitor pump performance. Key controls exist for waste temperature, gas concentration, pump parameters, and long-term waste behavior associated with the safe operation of the mixer pump that mitigates the buoyant displacement gas release event behavior of 241-SY-101. Table 1-1 compares the key controls and the current state of the waste as of December 31, 1998.

  14. Neutron and Gamma Probe Application to Hanford Tank 241-SY-101

    SciTech Connect

    CANNON, N.S.

    2000-02-01

    A neutron (moisture-sensitive) and gamma (in-situ radiation) probe technique has been utilized at a number of Hanford radioactive waste tanks for many years. This technology has been adapted for use in tank 241-SY-101's two Multifunction Instrument Trees (MITs) which have a hollow dry-well center opening two inches (51 cm) in diameter. These probes provide scans starting within a few inches of the tank bottom and traversing up through the top of the tank revealing a variety of waste features as a function of tank elevation. These features have been correlated with void fraction data obtained independently from two other devices, the Retained Gas Sampler (RGS) and the Void Fraction Instrument (VFI). The MIT probes offer the advantage of nearly continuous count-rate versus elevation scans and they can be operated significantly more often and at lower cost than temperature probes or the RGS or VFI devices while providing better depth resolution. The waste level in tank 241-SY-101 had been rising at higher rates than expected during 1998 and early 1999 indicating an increasing amount of trapped gas in the waste. The use of the MIT probes has assisted in evaluating changes in crust thickness and level and also in estimating relative changes in gas stored in the crust. This information is important in assuring that the tank remains in a safe configuration and will support safe waste transfer when those operations take place.

  15. Hazard evaluation for transfer of waste from tank 241-SY-101 to tank 241-SY-102

    SciTech Connect

    SHULTZ, M.V.

    1999-02-12

    Tank 241-SY-101 (SY-101) waste level growth is an emergent, high priority issue. The purpose of this document is to record the hazards evaluation process and document potential hazardous conditions that could lead to the release of radiological and toxicological material from the proposed transfer of a limited quantity (approximately 100,000 gallons) of waste from SY-101 to 241-SY-102 (SY-102). The results of the hazards evaluation will be compared to the current Tank Waste Remediation System (TWRS) Basis for Interim Operation (HNF-SD-WM-BIO-001, 1998, Revision 1) to identify any hazardous conditions where Authorization Basis (AB) controls may not be sufficient or may not exist. Comparison to LA-UR-92-3196, A Safety Assessment for Proposed Pump Mixing Operations to Mitigate Episodic Gas Releases in Tank 241-SY-101, was also made in the case of transfer pump removal activities. This document is not intended to authorize the activity or determine the adequacy of controls; it is only intended to provide information about the hazardous conditions associated with this activity. The Unreviewed Safety Question (USQ) process will be used to determine the adequacy of controls and whether the proposed activity is within the AB. This hazard evaluation does not constitute an accident analysis.

  16. 241-SY-101 data acquisition and control system (DACS) remote operator interface operational test report

    SciTech Connect

    ERMI, A.M.

    1999-06-24

    The readiness of the upgraded 241-SY-101 Data Acquisition and Control System (DACS) to provide proper control and monitoring of the mixer pump and instrumentation in tank 241-SY-101 was evaluated by the performance of OTP-440-001. Results of the OTP are reported here.

  17. 241-SY-101 DACS High hydrogen abort limit reduction (SCR 473) acceptance test report

    SciTech Connect

    ERMI, A.M.

    1999-09-09

    The capability of the 241-SY-101 Data Acquisition and Control System (DACS) computer system to provide proper control and monitoring of the 241-SY-101 underground storage tank hydrogen monitoring system utilizing the reduced hydrogen abort limit of 0.69% was systematically evaluated by the performance of ATP HNF-4927. This document reports the results of the ATP.

  18. Structural analysis and evaluation of the 241SY101 tank annulus heat-up

    SciTech Connect

    Ziada, H.H.

    1994-10-19

    This document provides the structural analysis (static and thermal loads) of the 241SY101 tank to determine the maximum allowable temperature and rate of heating that could be applied to tank 241SY101 through annulus air heating without detrimental effects to the structural integrity of the concrete and steel liner of the tank.

  19. 241-SY-101 data acquisition and control system (DACS) operator interface upgrade operational test report

    SciTech Connect

    ERMI, A.M.

    1999-05-11

    This procedure provides instructions for readiness of the first portion of the upgraded 241-SY-101 Data Acquisition and Control System (DACS) computer system to provide proper control and monitoring of the mitigation mixer pump and instrumentation installed in the 241-SY-101 underground storage tank will be systematically evaluated by the performance of this procedure.

  20. 241-SY-101 DACS instrument problem screen (SCR 448) acceptance test procedure

    SciTech Connect

    ERMI, A.M.

    1999-06-28

    The operability of the 241-SY-101 Data Acquisition and Control System (DACS) to provide proper control and monitoring of the mitigation mixer pump and instrumentation installed in the 241-SY-101 underground storage tank utilizing the [INSTPROB] screen will be systematically evaluated by the performance of this procedure.

  1. Solubilities of gases in simulated Tank 241-SY-101 wastes

    SciTech Connect

    Norton, J.D.; Pederson, L.R.

    1995-09-01

    Oxygen, nitrogen, hydrogen, methane, and nitrous oxide solubilities were evaluated as a function of temperature in SYl-SIM-93B, a homogeneous simulated waste mixture containing sodium hydroxide, sodium nitrite, sodium nitrate, sodium aluminate, and sodium carbonate, the principal inorganic constituents of the wastes in Tank 241-SY-101. Ammonia solubility data for this simulated waste was obtained as a function of temperature in an earlier study. The choice of a homogeneous waste mixture in this study has the advantage of eliminating complications associated with a changing electrolyte concentration as a function of temperature that would be encountered with a slurry simulant. Dissolution is one of the means by which gases may be retained in Hanford Site wastes. While models are available to estimate gas solubilities in electrolyte solutions, few data are in existence that pertain to highly concentrated, multicomponent electrolytes such as those stored in Hanford Site waste tanks.

  2. Tank 241-SY-101 push mode core sampling and analysis plan

    SciTech Connect

    CONNER, J.M.

    1998-10-09

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for push mode core samples from tank 241-SY-101 (SY-101). It is written in accordance with Data Quality Objective to Support Resolution of the Flammable Gas Safety Issue (Bauer 1998), Low Activity Waste Feed Data Quality Objectives (Wiemers and Miller 1997 and DOE 1998), Data Quality Objectives for TWRS Privatization Phase I: Confirm Tank T is an Appropriate Feed Source for Low-Activity Waste Feed Batch X (Certa 1998), and the Tank Safety Screening Data Quality Objective (Dukelow et al. 1995). The Tank Characterization Technical Sampling Basis document (Brown et al. 1998) indicates that these issues apply to tank SY-101 for this sampling event. Brown et al. also identifies high-level waste, regulatory, pretreatment and disposal issues as applicable issues for this tank. However, these issues will not be addressed via this sampling event.

  3. In situ determination of rheological properties and void fraction in Hanford Waste Tank 241-SY-101

    SciTech Connect

    Stewart, C.W.; Shepard, C.L.; Alzheimer, J.M.; Stokes, T.I.; Terrones, G.

    1995-08-01

    This report presents the results of the operation of the void fraction instrument (VFI) and ball rheometer in Hanford Tank 241-SY-101, which contains approximately one million gallons of radioactive waste. These instruments provided the first direct assay of the waste condition in the tank after more than a year of mixer pump operation. The two instruments were deployed in the tank in late 1994 and early 1995 to gather much-needed data on the effect prolonged mixer pump operation has on gas retention in the waste. The information supplied by these instruments has filled a great gap in the quantitative knowledge of the waste condition. The results show that the solids are well-mixed by the current mixer pump to within less than a meter of the tank bottom. Undisturbed sludge remains only on the lowest 10--30 cm and contains 10--12% void. The mixed slurry above contains less than 1% void and has no measurable yield strength and a shear-thinning viscosity of approximately 6 Poise at 1 sec{sup {minus}1}. Estimating the gas volumes in each of the four layers based on VFI data yields a total of 221 {+-} 57 m{sup 3} (7,800 {+-} 2,000 SCF) of gas at 1 atmosphere. Given the current waste level of 10.2 m (400 inches), the degassed waste level would be 9.8 m (386 inches). These results confirm that the mixer pump in Tank 241-SY-101 has performed the job it was installed to do--thoroughly mix the waste to release stored gas and prevent gas accumulation.

  4. Closed out Tank 241-SY-101 DACS system change request {number_sign}1--100

    SciTech Connect

    Gauck, G.J.

    1995-03-07

    This report is a compilation of system change requests processed during the development of the Data Acquisition and Control System for the Tank 241-SY-101 hydrogen mitigation project. Tank 241-SY-101 is on the Hydrogen Watch List. The disposition of the request, date the change was installed, date verified, and whether an Acceptance Test Procedure was required and completed are described for each request change.

  5. 241-SY-101 mixer pump lifetime expectancy. Final report

    SciTech Connect

    Shaw, C.P.

    1995-12-08

    The purpose of WHC-SD-WM-TI-726, Rev. 0 241-SY-101 Mixer Pump Lifetime Expectancy is to determine a best estimate of the mean lifetime of non-repairable (located in the waste) essential features of the hydrogen mitigation mixer pump presently installed in 101-SY. The estimated mean lifetime is 9.1 years. This report does not demonstrate operation of the entire pump assembly within the Tank Farm ``safety envelope``. It was recognized by the Defense Nuclear Facilities Safety Board (DNFSB) this test pump was not specifically designed for long term service in tank 101-SY. In June 95 the DNFSB visited Hanford and ask the question, ``how long will this test pump last and how will the essential features fail?`` During the 2 day meeting with the DNFSB it was discussed and defined within the meeting just exactly what essential features of the pump must operate. These essential features would allow the pump to operate for the purpose of extending the window for replacement. Operating with only essential features would definitely be outside the operating safety envelope and would require a waiver. There are three essential features: 1. The pump itself (i.e. the impeller and motor) must operate 2. Nozzles and discharges leg must remain unplugged 3. The pump can be re-aimed, new waste targeted, even if manually.

  6. Miscellaneous component design for Tank 241SY101 pump removal

    SciTech Connect

    Huang, F.H.

    1995-03-02

    A mixer pump has been used to mitigate the hydrogen build-up in tank 241SY101 (SY101), located in the 200 West Area of the Hanford Site. New equipment is being prepared for the removal, transport, storage, and disposal of the test pump. The disposal equipment for the test pump now in tank SY101 includes a shipping container, a strong back, a lifting beam, a test weight, container support stands, a modified mock-up pump, a flexible receiver blast shield, a lifting yoke, and a yoke brace. The structural evaluations of container and strong back are detailed in another supporting document (WHC 1994a), the engineering analyses of flexible receiver blast shield/lifting yoke and yoke brace are given in other supporting documents (WHC 1994b, WHC 1994c), respectively. Engineering tasks that were contracted to Advanced Engineering Consultants (AEC) include the design and analysis of the following. Two spreader-beam lifting devices. a Container test weight. Container support saddles. Mock-up pump modification. This report documents the work description, design basis, assumptions, and design calculations provided by AEC for the above components. All AEC documents appear in Appendix A. Additional work conducted by Westinghouse Hanford Company (WHC) on the modified container test weight, modification to the mock-up pump, the removable support for the transport assembly, and saddle modification for air pallets also are included in this document.

  7. Dynamics of Crust Dissolution and Gas Release in Tank 241-SY-101

    SciTech Connect

    SD Rassat; CW Stewart; BE Wells; WL Kuhn; ZI Antoniak; JM Cuta; KP Recknagle; G Terrones; VV Viswanathan; JH Sukamto; DP Mendoza

    2000-01-26

    Due primarily to an increase in floating crust layer thickness, the waste level in Hanford Tank 241-SY-101 (SY-101) has grown appreciably, and the flammable gas volume stored in the crust has become a potential hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from the nonconnective layer at the bottom of the tank, SY-101 will be diluted to dissolve a large fraction of the solids that allow the waste to retain gas. In this work we develop understanding of the state of the tank waste and some of its physical properties, investigate how added water will be distributed in the tank and affect the waste, and use the information to evaluate mechanisms and rates of waste solids dissolution and gas release. This work was completed to address these questions and in support of planning and development of controls for the SY-101 Surface Level Rise Remediation Project. Particular emphasis is given to dissolution of and gas release from the crust, although the effects of back-dilution on all waste layers are addressed. The magnitude and rates of plausible gas release scenarios are investigated, and it is demonstrated that none of the identified mechanisms of continuous (dissolution-driven) or sudden gas release, even with conservative assumptions, lead to domespace hydrogen concentrations exceeding the lower flammability limit. This report documents the results of studies performed in 1999 to address the issues of the dynamics, of crust dissolution and gas release in SY-101. It contains a brief introduction to the issues at hand; a summary of our knowledge of the SY-101 crust and other waste properties, including gas fractions, strength and volubility; a description of the buoyancy and dissolution models that are applied to predict the crust response to waste transfers and back dilution; and a discussion of the effectiveness of mixing for water added below the crust and the limited potential for significant stratification

  8. Assessment of gas accumulation and retention -- Tank 241-SY-101

    SciTech Connect

    Alleman, R.T.; Burke, T.M.; Reynolds, D.A.; Simpson, D.E.

    1993-03-01

    An approximate analysis has been carried out to assess and estimate the maximum quantity of gas that is likely to be accumulated within waste tank 241-SY-101, and the maximum quantity which is likely to be retained after gas release events (GRE). According to the phenomenological models used for this assessment, based on interpretation of current and recent operational data, the estimated gas generation rate in the tank is approximately 4 m{sup 3}/day (147 ft{sup 3}/day). About half of this gas is released as it is generated, which is (essentially) continuously. The remainder is accumulated within the slurry layer of settled solids at the bottom of the tank, and released episodically in GREs, known as ``burps,`` that are induced by unstable buoyant conditions which develop when sufficient gas accumulates in the slurry. Calculations based on gas volumes to cause neutral buoyancy in the slurry predict the following: the maximum gas accumulation (at 1 atm pressure) that can occur without triggering a GRE is in the range of 606 to 1,039 m{sup 3} (21,400 to 36,700 ft{sup 3}); and the maximum gas retention immediately after a GRE is equal to the maximum accumulation minus the gas released in the GRE. GREs do not necessarily involve all of the slurry. In the largest GREs, which are assumed to involve all of the slurry, the minimum gas release (at 1 atm pressure) is calculated to be in the range of 193 to 328 m{sup 3} (6,800 to 11,600 ft{sup 3}). The corresponding maximum gas retention would be 413 to 711 m{sup 3} (14,600 to 25,100 ft{sup 3}).

  9. Quarterly review of 241-SY-101 mixer pump data: January - March 1999

    SciTech Connect

    CONNER, J.M.

    1999-07-22

    This report presents data obtained on 241-SY-101 pump performance. The period covered is January 1 through March 31, 1999. During the quarter: There were changes in pumping parameters. Both the pump volute pressure and amperage decreased during the quarter. It is not clear whether this was due to changes in waste properties (due to less solids or more entrained gas) or due to degradation of the pump. There was an indication of a 7.5-inch increase in the waste level at riser 1 A, and an average growth rate of 0.082 inches per day. There was an indication of a 5.7-inch increase in the waste level at riser 1C. This riser was flushed with water several times, which would lower the level of the crust at this location. Gases continued to be released at less than the pre-pump installation baseline rate, indicating a decrease in the gas generation rate, or an increase in gas retention, or both. The release rate was about 78 percent of the rate in the previous few quarters, and only 34 percent of the generation rate calculated prior to mixer pump installation in 1993. Key controls exist for waste temperature, gas concentration, pump parameters, and long-term waste behavior associated with the safe operation of the mixer pump that mitigates the buoyant displacement gas release event behavior of 241-SY-101. Table 1-1 compares the key controls and the current state of the waste as of March 3 1. 1999. The pump was run 28 times between January 1 and March 31, 1999. All of the pump runs were intended to be normal 25-minute, 1000-rpm excavation runs performed to mix the waste and release gas. Because of the pump oil often reached the high temperature alarm setpoint of 190 F, many of the runs were shortened (by as many as 8 minutes). This phenomenon was identified in November 1998, but got progressively worse over the quarter. The pump schedule was nominally three runs per week. However, core sampling activities interrupted the usual pump schedule several times during the quarter

  10. Quarterly Review of 241SY101 Mixer Pump Data 10/1998 Thru 12/1998

    SciTech Connect

    CONNER, J.M.

    1999-05-11

    This report presents data obtained on 241-SY-101 pump performance. The period covered is October 1 through December 31, 1998. During the quarter: (1) There was an indication of a 7.0-inch increase in the waste level at riser 1A, and an average growth rate of 0.076 inches per day; (2) There was an indication of a 2.3-inch increase in the waste level at riser 1C; (3) This riser was flushed with water several times, which would lower the level of the crust at this location; (4) Gases continued to be released at less than the pre-pump installation baseline rate, indicating a decrease in the gas generation rate, or an increase in gas retention, or both. The release rate was about 60 percent of the rate in the previous few quarters, and only 44 percent of the pre-pump release rate; and (5) There was no change in the parameters that monitor pump performance.

  11. Mitigation of tank 241-SY-101 by pump mixing: Results of full-scale testing

    SciTech Connect

    Stewart, C.W.; Hudson, J.D.; Friley, J.R.; Panisko, F.E.; Antoniak, Z.I.; Irwin, J.J.; Fadeff, J.G.; Efferding, L.F.; Michener, T.E.; Kirch, N.W.

    1994-06-01

    The Full-Scale Mixer Pump Test Program was performed in Hanford Tank 241-SY-101 from February 4 to April 13, 1994, to confirm the long-term operational strategy for flammable gas mitigation and to demonstrate that mixing can control the gas release and waste level. Since its installation on July 3, 1993, the current pump, operating only a few hours per week, has proved capable of mixing the waste sufficiently to release gas continuously instead of in large episodic events. The results of Full-Scale Testing demonstrated that the pump can control gas release and waste level for long-term mitigation, and the four test sequences formed the basis for the long-term operating schedule. The last test sequence, jet penetration tests, showed that the current pump jet creates flow near the tank wall and that it can excavate portions of the bottom sludge layer if run at maximum power. Pump mixing has altered the {open_quote}normal{close_quote} configuration of the waste; most of the original nonconvective sludge has been mixed with the supernatant liquid into a mobile convective slurry that has since been maintained by gentle pump operation and does not readily return to sludge.

  12. 1/12-scale physical modeling experiments in support of tank 241-SY- 101 hydrogen mitigation

    SciTech Connect

    Fort, J.A.; Bamberger, J.A.; Bates, J.M.; Enderlin, C.W.; Elmore, M.R.

    1993-01-01

    Hanford tank 241-SY-101 is a 75-ft-dia double-shell tank that contains approximately 1.1 M gal of radioactive fuel reprocessing waste. Core samples have shown that the tank contents are separated into two main layers, a article laden supernatant liquid at the top of the tank and a more dense slurry on the bottom. Two additional layers may be present, one being a potentially thick sludge lying beneath the slurry at the bottom of the tank and the other being the crust that has formed on the surface of the supernatant liquid. The supernatant is more commonly referred to as the convective layer and the slurry as the non-convective layer. Accumulation of gas (partly hydrogen) in the non-convective layer is suspected to be the key mechanism behind the gas burp phenomena, and several mitigation schemes are being developed to encourage a more uniform gas release rate (Benegas 1992). To support the full-scale hydraulic mitigation test, scaled experiments were performed to satisfy two objectives: 1. provide an experimental database for numerical- model validation; 2. establish operating parameter values required to mobilize the settled solids and maintain the solids in suspension.

  13. Dynamics of Crust Dissolution and Gas Release in Tank 241-SY-101

    SciTech Connect

    Rassat, Scot D.; Stewart, Charles W.; Wells, Beric E.; Kuhn, William L.; Antoniak, Zenen I.; Cuta, Judith M.; Recknagle, Kurtis P.; Terrones, Guillermo; Viswanathan, Vilayanur V.; Sukamto, Johanes H.; Mendoza, Donaldo P.

    2000-01-24

    Due primarily to an increase in floating crust thickness, the waste level in Tank 241-SY-101 has grown appreciably and the flammable gas volume stored in the crust has become a potential hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from the nonconvective layer at the bottom of the tank, SY-101 will be diluted to dissolve a large fraction of the solids that allow the waste to retain gas. The plan is to transfer some waste out and back-dilute with water in several steps. In this work, mechanisms and rates of waste solids dissolution and gas releases are evaluated theoretically and experimentally. Particular emphasis is given to crust dissolution processes and associated gas releases, although dissolution and gas release from the mixed-slurry and nonconvective layers are also considered. The release of hydrogen gas to the tank domespace is modeled for a number of scenarios. Under the tank conditions expected at the time of back-dilution, no plausible continuous or sudden gas release scenarios resulting in flammable hydrogen concentrations were identified.

  14. Evaluation of the generation and release of flammable gases in tank 241-SY-101

    SciTech Connect

    Babad, H.; Johnson, G.D.; Lechelt, J.A.; Reynolds, D.A. ); Pederson, L.R.; Strachan, D.M. ); Meisel, D.; Jonah, C. ); Ashby, E.C. )

    1991-11-01

    Tank 241-SY-101 is a double shell, high-level waste tank located in the 200 West Area of the Hanford Site. This tank contains about 1 million gallons of waste that was concentrated at the 242-S Evaporator. Shortly after the waste was put in the tank, the waste began to expand because the generation of gases. In 1990 this tank was declared to have an unreviewed safety question because of the periodic release of hydrogen and nitrous oxide. A safety program was established to conduct a characterization of the waste and vented gases and to determine an effective means to prevent the accumulation of flammable gases in the tank dome space and ventilation system. Results of the expanded characterization conducted in fiscal year 1991 are presented. The use of gas chromatographs, mass spectrometers, and hydrogen-specific monitors provided a greater understanding of the vented gases. Additional instrumentation placed in the tank also helped to provide more detailed information on tank temperatures, gas pressure, and gas flow rates. An extensive laboratory study involving the Westinghouse Hanford Company, Pacific Northwest Laboratory, Argonne National Laboratory, and the Georgia Institute of Technology was initiated for the purpose of determining the mechanisms responsible for the generation of various gases. These studies evaluate both radiolytic and thermochemical processes. Results of the first series of experiments are described.

  15. Mixer pump long term operations plan for Tank 241-SY-101 mitigation

    SciTech Connect

    Irwin, J.J.

    1994-09-07

    This document provides the general Operations Plan for performance of the mixer pump long term operations for Tank 241-SY-101 mitigation of gas retention and periodic release in Tank 101-SY. This operations plan will utilize a 112 kW (150 hp) mixing pump to agitate/suspend the particulates in the tank.

  16. Thermal analysis of tank 241-SY-101 to support structural assessment

    SciTech Connect

    Beaver, T.R.

    1994-10-14

    This report documents a thermal model of tank 241-SY-101 and the surrounding soil column that was used to predict tank temperatures resulting from heating of the annulus ventilation air. Transient results from the model were input to a structural model of the tank for evaluation of the annulus heat-up event.

  17. An assessment of the dilution required to mitigate Hanford tank 241-SY-101

    SciTech Connect

    Hudson, J.D.; Bredt, P.R.; Felmy, A.R.; Stewart, C.W.; Tingey, J.M.; Trent, D.S.; Barney, G.S.; Herting, D.L.; Larrick, A.P.; Reynolds, D.A.

    1995-02-01

    A group of experts from PNL and WHC convened November 2 and 3, 1994, to screen the current state of knowledge about dilution and reach a consensus on the minimum dilution ratio that will achieve passive mitigation of Tank 241-SY-101 wastes and the dilution ratio that would satisfy the given cross-site transfer criteria with reasonable assurance. The panel evaluated the effects of dilution on the parameters important in gas generation, retention, and release and reached the following conclusions, which are deduced from the existing body of data, experience, and analyses: (1) Dissolution of solids is the single most important aspect of mitigation by dilution. We are confident that diluting until nitrates, nitrites, and aluminum salts are dissolved will mitigate Hanford flammable gas tanks; (2) Sufficient solids dissolution can be achieved in Tank 241-SY-101 at a dilution ratio of 1:1, which will result in a average specific gravity of approximately 1.35. It is likely that a 0.5:1 dilution will also mitigate 241-SY-101, but the current uncertainty is too high to recommend this dilution ratio; (3) The recommended dilution requires a diluent with at least 2 molar free hydroxide, because aluminum probably precipitates at lower hydroxide concentrations. The transfer criteria for Tank 241-SY-101 waste were also evaluated. These criteria have been specified as solids content {<=}30% (volume), viscosity {<=}30% cP and density <1.5 g/mL. (1) Solids content is the limiting criterion if it is defined as volume fraction of settled solids. A 1:1 dilution will satisfy this criterion at nominal premixing conditions in Tank 241-SY-101; however, analysis of Window E core samples suggests that up to 1.5:1 might be required. If the solids content is interpreted simply as solids volume fraction no further dilution is necessary, because Tank 241-SY-101 waste (excluding the crust) is already below 30%; (2) Bulk density is the next limiting criterion and is met at 0.4:1 dilution.

  18. Results of Waste Transfer and Back-Dilution in Tanks 241-SY-101 and 241-SY-102

    SciTech Connect

    LA Mahoney; ZI Antoniak; WB Barton; JM Conner; NW Kirch; CW Stewart; BE Wells

    2000-07-26

    This report chronicles the process of remediation of the flammable gas hazard in Tank 241-SY-101 (SY-101) by waste transfer and back-dilution from December 18, 1999 through April 2, 2000. A brief history is given of the development of the flammable gas retention and release hazard in this tank, and the transfer and dilution systems are outlined. A detailed narrative of each of the three transfer and dilution campaigns is given to provide structure for the balance of the report. Details of the behavior of specific data are then described, including the effect of transfer and dilution on the waste levels in Tanks SY-101 and SY-102, data from strain gauges on equipment suspended from the tank dome, changes in waste configuration as inferred from neutron and gamma logs, headspace gas concentrations, waste temperatures, and the mixerpump operating performance. Operating data and performance of the transfer pump in SY-101 are also discussed.

  19. Acceptance test procedure, 241-SY-101/241-C-106 shot loading system

    SciTech Connect

    Ostrom, M.J.

    1994-11-01

    This Acceptance Test Procedure is for the 241-SY-101/241-C-106 Shot Loading System. The procedure will test the components of the Shot Loading System and its capability of adequately loading shot into the annular space of the Container. The loaded shot will provide shielding as required for transporting and storage of a contaminated pump after removal from the tank. This test serves as verification that the SLS is acceptable for use in the pump removal operations for Tanks 241-SY-101, 241-C-106 and 241-AY-102. The pump removal operation for these three tanks will be performed by two different organizations with different equipment, but the Shot Loading System will be compatible between the two operations.

  20. Thermocouple module halt failure acceptance test procedure for Tank 241-SY-101 DACS-1

    SciTech Connect

    Ermi, A.M.

    1997-12-09

    The readiness of the Tank 241-SY-101 Data Acquisition and Control System (DACS-1) to provide monitoring and alarms for a halt failure of any thermocouple module will be tested during the performance of this procedure. Updated DACS-1 ``1/0 MODULE HEALTH STATUS``, ``MININ1``, and ``MININ2`` screens, which now provide indication of thermocouple module failure, will also be tested as part of this procedure.

  1. Acceptance and operational test procedure for neutron and gamma probe application to tank 241-SY-101 MITs

    SciTech Connect

    CANNON, N.S.

    1999-06-02

    This ATP/OTP provides procedures for testing to be performed to verify that newly procured neutron and gamma probes (reduced diameter design modifications) for operation in the Tank 241-SY-101 MlTs are compatible with existing LOW van instrumentation and hardware. A set of moisture data versus elevation will be obtained from the Tank 241-SY-101 MITs, and (optionally) from the Tank 241-AX-I01 LOW as part of this testing program.

  2. Acceptance and Operational Test Report for Neutron and Gamma Probe Application to Tank 241-SY-101 MITs

    SciTech Connect

    CANNON, N.S.

    1999-08-12

    This Operational Test Report (OTR) presents the results of the ATP/OTP testing performed to verify that newly procured neutron and gamma probes (reduced diameter design modifications) for operation in the Tank 241-SY-101 MITs are compatible with existing LOW van instrumentation and hardware. This verification was accomplished and a set of moisture data versus elevation were obtained from the Tank 241-SY-101 MITs as part of this testing program.

  3. The Potential for Buoyant Displacement Gas Release Events in Tank 241-SY-102 after Waste Transfer from Tank 241-SY-101

    SciTech Connect

    Wells, Beric E.; Meyer, Perry A.; Chen, Guang

    2000-04-10

    Tank 241-SY-101 is a double-shell radioactive waste storage tank containing waste that, before recent transfer and water back-dilution operations, was capable of retaining gas and producing flammable buoyant displacement gas release events (BD GREs). A BD GRE occurs when a portion of the nonconvective layer waste retains enough gas to become buoyant, rises to the waste surface, breaks up, and releases some of the stored gas. Installing the mixer pump in 1993 successfully mitigated gas retention in the settled solids layer in SY-101 and has prevented BD GREs. Gas retention in the floating drust layer and the corresponding accelerated waste level growth made it necessary to begin waste removal and back-dilution with water in December 1999. During these operations, some of the SY-101 mixed slurry layer is removed and transferred into Tank 241-SY-102. There was some concern that adding the SY-101 waste into SY-102 could create a waste configuration in SY-102 capable of BD GREs. This report updates and extends earlier assessments of the potential for BD GRE conditions in SY-102 after waste is transferred from SY-101. We determined that, under the given assumptions, no possibility of BD GREs exists in SY-102 from the SY-101 waste being added during from December 1999 through March 2000.

  4. Buoyant Response of the Tank 241-SY-101 Crust to Transfer and Back-Dilution

    SciTech Connect

    CW Stewart

    1999-11-08

    The mixer pump installed in Hanford Tank 241-SY-101 (SY-101) in July 1993 has prevented the large buoyant displacement gas release events (BD GRE) it has historically exhibited. But the absence of periodic disruption from GREs and the action of mixing have allowed the crust to grow. The accelerated gas retention has resulted in over 30 inches of waste level growth and the flammable gas volume stored in the crust has become a hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from below the crust, SY-101 will be diluted in the fall of 1999 to dissolve a large fraction of the solids in the tank. The plan is to transfer waste out and back-dilute with water in several steps of about 100,000 gallons each. Back-dilution water may be added at the transfer pump inlet, the base of the mixer pump, and on top of the crust. The mixer pump will continue to be required to prevent formation of a deep nonconnective layer and resumption of BD GREs. Therefore, it is vital to ensure that the transfer and back-dilution processes do not significantly degrade the pump's effectiveness. Part of the strategy to avoid mixer pump degradation is to keep the base of the crust layer well above the pump inlet, which is 236 inches above the tank bottom. The maximum transfer for which an equal back-dilution is possible without sinking the crust is 90 kgal if water is injected at the 96-inch transfer pump inlet and 120 kgal for injection at the 9-inch mixer pump burrowing ring. To keep the crust base above the lowest observed elevation of 295 inches, transfer and back-dilution must be limited to 143 kgal and 80 kgal, respectively, for the 96-inch back-dilution and 175 kgal with a 112 kgal back-dilution using the 9-inch back-dilution elevation. These limits can be avoided by adding water to the top of the crust to dissolve the negatively buoyant layers. If 20 kgal of water is placed on top of the crust and the rest of the back-dilution is placed

  5. The behavior, quantity, and location of undissolved gas in Tank 241-SY-101

    SciTech Connect

    Brewster, M.E.; Gallagher, N.B.; Hudson, J.D.; Stewart, C.W.

    1995-10-01

    Mitigation of episodic flammable gas releases from Hanford Waste Tank 241-SY-101 was accomplished in July 1993 with the installation of a mixer pump that prevents gas retention. But is has not been possible until recently to measure the effects of mixing on the waste or how much gas remains and where it is located. Direct measurements of the void fraction and rheology of the mixed waste by the void fraction instrument (VFI) and ball rheometer along with previous data provide estimates of the location, quantity, and behavior of undissolved gas in the tank. This report documents the compilation and integration of the information that enables this understanding.

  6. Engineering test plan for Tank 241-SY-101 in situ viscometer

    SciTech Connect

    Sobocinski, R.G.; Stokes, T.I.; Pearce, K.L.

    1994-11-01

    To obtain in situ measurements of the rheological properties within tank 241-SY-101, this document will implement the test strategy defined in PNLMIT-041994, acquisition and Reduction of Data Obtained in Tank SY-101 with the Ball Rheometer. Instructions for all sequences are defined within the procedure. All safety requirements as defined in LA-UR-92-3196, A Safety Assessment for Proposed Mixing Operations to Mitigate Episodic Gas Releases in Tank 241-101-SY have been implemented into this procedure.

  7. Ultrasonic Examination of Double-Shell Tank 241-SY-101. Examination Completed March 2004.

    SciTech Connect

    Pardini, Allan F.; Posakony, Gerald J.

    2004-07-22

    COGEMA Engineering Corporation (COGEMA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic nondestructive examination of selected portions of Double-Shell Tank 241-SY-101. The purpose of this examination was to provide information that could be used to evaluate the integrity of the wall of the primary tank. The requirements for the ultrasonic examination of Tank 241-SY-101 were to detect, characterize (identify, size, and locate), and record measurements made of any wall thinning, pitting, or cracks that might be present in the wall of the primary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-17750 (Jensen 2003) and summarized on page 1 of this document, are reported to CH2M Hill and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M Hill, all data is to be recorded on disk and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a report that describes the results of the COGEMA ultrasonic examinations.

  8. Ultrasonic Examination of Double-Shell Tank 241-SY-101. Examination Completed March 2004.

    SciTech Connect

    Pardini, Allan F.; Posakony, Gerald J.

    2004-05-25

    COGEMA Engineering Corporation (COGEMA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic nondestructive examination of selected portions of Double-Shell Tank 241-SY-101. The purpose of this examination was to provide information that could be used to evaluate the integrity of the wall of the primary tank. The requirements for the ultrasonic examination of Tank 241-SY-101 were to detect, characterize (identify, size, and locate), and record measurements made of any wall thinning, pitting, or cracks that might be present in the wall of the primary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-17750 (Jensen 2003) and summarized on page 1 of this document, are reported to CH2M Hill and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M Hill, all data is to be recorded on disk and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a report that describes the results of the COGEMA ultrasonic examinations.

  9. Numerical simulation of jet mixing concepts in Tank 241-SY-101

    SciTech Connect

    Trent, D.S.; Michener, T.E.

    1993-03-01

    The episodic gas release events (GRES) that have characterized the behavior of Tank 241-SY-101 for the past several years are thought to result from gases generated by the waste material in it that become trapped in the layer of settled solids at the bottom of the tank. Several concepts for mitigating the GREs have been proposed. One concept involves mobilizing the solid particles with mixing jets. The rationale behind this idea is to prevent formation of a consolidated layer of settled solids at the bottom of the tank, thus inhibiting the accumulation of gas bubbles in this layer. Numerical simulations were conducted using the TEMPEST computer code to assess the viability and effectiveness of the proposed jet discharge concepts and operating parameters. Before these parametric studies were commenced, a series of turbulent jet studies were conducted that established the adequacy of the TEMPEST code for this application. Configurations studied for Tank 241-SY-101 include centrally located downward discharging jets, draft tubes, and horizontal jets that are either stationary or rotating. Parameter studies included varying the jet discharge velocity, jet diameter, discharge elevation, and material properties. A total of 18 simulations were conducted and are reported in this document. The effect of gas bubbles on the mixing dynamics was not included within the scope of this study.

  10. 1/12-scale physical modeling experiments in support of tank 241-SY- 101 hydrogen mitigation. Final report

    SciTech Connect

    Fort, J.A.; Bamberger, J.A.; Bates, J.M.; Enderlin, C.W.; Elmore, M.R.

    1993-01-01

    Hanford tank 241-SY-101 is a 75-ft-dia double-shell tank that contains approximately 1.1 M gal of radioactive fuel reprocessing waste. Core samples have shown that the tank contents are separated into two main layers, a article laden supernatant liquid at the top of the tank and a more dense slurry on the bottom. Two additional layers may be present, one being a potentially thick sludge lying beneath the slurry at the bottom of the tank and the other being the crust that has formed on the surface of the supernatant liquid. The supernatant is more commonly referred to as the convective layer and the slurry as the non-convective layer. Accumulation of gas (partly hydrogen) in the non-convective layer is suspected to be the key mechanism behind the gas burp phenomena, and several mitigation schemes are being developed to encourage a more uniform gas release rate (Benegas 1992). To support the full-scale hydraulic mitigation test, scaled experiments were performed to satisfy two objectives: 1. provide an experimental database for numerical- model validation; 2. establish operating parameter values required to mobilize the settled solids and maintain the solids in suspension.

  11. Waste tank 241-SY-101 dome airspace and ventilation system response to a flammable gas plume burn

    SciTech Connect

    Heard, F.J.

    1995-11-01

    A series of flammable gas plume burn and transient pressure analyses have been completed for a nuclear waste tank (241-SY-101) and associated tank farm ventilation system at the U.S. Department of Energy`s Hanford facility. The subject analyses were performed to address issues concerning the effects of transient pressures resulting from igniting a small volume of concentrated flammable gas just released from the surface of the waste as a plume and before the flammable gas concentration could be reduced by mixing with the dome airspace by local convection and turbulent diffusion. Such a condition may exist as part of an in progress episode gas release (EGR) or gas plume event. The analysis goal was to determine the volume of flammable gas that if burned within the dome airspace would result in a differential pressure, after propagating through the ventilation system, greater than the current High Efficiency Particulate Filter (HEPA) limit of 2.49 KPa (10 inches of water or 0. 36 psi). Such a pressure wave could rupture the tank ventilation system inlet and outlet HEPA filters leading to a potential release of contaminants to the environment

  12. Buoyancy and Dissolution of the Floating Crust Layer in Tank 241-SY-101 During Transfer and Back-Dilution

    SciTech Connect

    CW Stewart; JH Sukamto; JM Cuta; SD Rassat

    1999-11-22

    To remediate gas retention in the floating crust layer and the potential for buoyant displacement gas releases from below the crust, waste will be transferred out of Hanford Tank 241-SY-101 (SY-101) in the fall of 1999 and back-diluted with water in several steps of about 100,000 gallons each. To evaluate the effects of back-dilution on the crust a static buoyancy model is derived that predicts crust and liquid surface elevations as a function of mixing efficiency and volume of water added during transfer and back-dilution. Experimental results are presented that demonstrate the basic physics involved and verify the operation of the models. A dissolution model is also developed to evaluate the effects of dissolution of solids on crust flotation. The model includes dissolution of solids suspended in the slurry as well as in the crust layers. The inventory and location of insoluble solids after dissolution of the soluble fraction are also tracked. The buoyancy model is applied to predict the crust behavior for the first back-dilution step in SY-101. Specific concerns addressed include conditions that could cause the crust to sink and back-dilution requirements that keep the base of the crust well above the mixer pump inlet.

  13. In Situ Void Fraction and Gas Volume in Hanford Tank 241-SY-101 as Measured with the Void Fraction Instrument

    SciTech Connect

    CW Stewart; G Chen; JM Alzheimer; PA Meyer

    1998-11-10

    The void fraction instrument (WI) was deployed in Tank 241-SY-101 three times in 1998 to confm and locate the retained gas (void) postulated to be causing the accelerating waste level rise observed since 1995. The design, operation, and data reduction model of the WI are described along with validation testing and potential sources of uncertainty. The test plans, field observations and void measurements are described in detail, including the total gas volume calculations and the gas volume model. Based on 1998 data, the void fraction averaged 0.013 i 0.001 in the mixed slurry and 0.30 ~ 0.04 in the crust. This gives gas volumes (at standard pressure and temperature) of 87 t 9 scm in the slurry and 138 ~ 22 scm in the crust for a total retained gas volume of221 *25 scm. This represents an increase of about 74 scm in the crust and a decrease of about 34 scm in the slurry from 1994/95 results. The overall conclusion is that the gas retention is occurring mainly in the crust layer and there is very little gas in the mixed slurry and loosely settled layers below. New insights on crust behavior are also revealed.

  14. The potential for buoyant displacement gas release events in Tank 241-SY-102 after waste transfer from Tank 241-SY-101

    SciTech Connect

    BE Wells; PE Meyer; G Chen

    2000-05-10

    Tank 241-SY-101 (SY-101) is a double-shell, radioactive waste storage tank with waste that, before the recent transfer and water back-dilution operations, was capable of retaining gas and producing buoyant displacement (BD) gas release events (GREs). Some BD GREs caused gas concentrations in the tank headspace to exceed the lower flammability limit (LFL). A BD GRE occurs when a portion of the nonconvective layer retains enough gas to become buoyant, rises to the waste surface, breaks up, and releases some of its stored gas. The installation of a mixer pump in 1993 successfully mitigated gas retention in the settled solids layer in SY-101 and has since prevented BD GREs. However, operation of the mixer pump over the years caused gas retention in the floating crust layer and a corresponding accelerated waste level growth. The accelerating crust growth trend observed in 1997--98 led to initiation of sequences of waste removal and water back-dilutions in December 1999. Waste is removed from the mixed slurry layer in Tank SY-101 and transferred into Tank 241-Sy-102 (SY-102). Water is then added back to dissolve soluble solids that retain gas. The initial transfer of 89,500 gallons of SY-101 waste, diluted in-line at 0.94:1 by volume with water, to SY-102 was conducted in December 1999. The second transfer of 230,000 gallons of original SY-101 waste, diluted approximately 0.9:1, was completed in January 2000, and the third transfer of 205,500 gallons of original SY-101 waste diluted at 0.9:1 was completed in March 2000.

  15. Type B Investigation Report for 241-SY-101 Pump Start and 241-C-106 Pit Cleanout

    SciTech Connect

    Ewalt, J.R.

    1993-09-01

    In accordance with the direction of the Department of Energy (DOE) Manager, Richland Operations Office, a Type ``B`` investigation in accordance with the DOE Order 5484.1, Environmental Protection, Safety and Health Protection Information Reporting Requirements, has been conducted. The scope of the investigation included two events: The ``Inadvertent Mixer Pump Operation at 241-SY-101`` (RL-WHC-TANK FARM-1993-069); ``Inadequate Work Control Results in Personnel Skin Contamination at 241-C-106, Pit B`` (RL-WHC-TANK FARM-1993-071) events. Additionally, at the request of the President of the WHC, a broader investigation into Waste Tank Farm ``safety practices`` and ``Conduct of Operations`` was also conducted. The review was focused on (1) WHC organizations performing operations, maintenance, and radiological safety tasks; and (2) KEH organizations performing major maintenance tasks.

  16. Simulation and rheological analysis of Hanford Tank 241-SY-101. Final report

    SciTech Connect

    Sams, E.C.; Tennant, R.A.; Piccola, J.P. Jr.

    1993-10-01

    Rheological characterization and small scale simulation of Hanford Tank 241-SY-101 has been initiated to aid in the remediation efforts for the Department of Energy Hanford Site. The study has been initiated in response to growing concerns about the potential flammability hazard pertaining to the periodic release of up to 10,000 cubic feet of hydrogen, nitrous oxide, nitrogen, and ammonia gases. Various stimulants emulating the radioactive waste stored in this tank have been used to ascertain the rheological parameters of the waste, simulate the ongoing processes of gas generation and release phenomenon inside the tank, and determine the feasibility of jet mixing to achieve a controlled release of the gas mixture.

  17. A survey of available information on gas generation in tank 241-SY-101

    SciTech Connect

    Strachan, D.M. ); Reynolds, D.A. ); Siemer, D.D. ); Wallace, R.W. )

    1991-03-01

    As a result of a concerted effort to determine the chemical and physical mechanisms underlying the generation and episodic release of gases from tank 241-SY-101, more commonly known as tank 101-SY, the Tank Waste Science Panel has been established at the Pacific Northwest Laboratory. Four of the members of this panel met to screen the available information on tank 101-SY and provide to the remaining members a shortened list of references that could be used to assess the mechanisms underlying the generation and episodic release of gases from tank 101-SY. This document is the result of this preliminary screening of information for the Tank Waste Science Panel and was provided to the Panel members at their first meeting. 14 refs., 3 tabs.

  18. 241-SY-101 strain concentration factor development via nonlinear analysis. Volume 1 of 1

    SciTech Connect

    1997-03-01

    The 241-SY-101 waste storage tank at the Hanford-Site has been known to accumulate and release significant quantities of hydrogen gas. An analysis was performed to assess the tank`s structural integrity when subjected to postulated hydrogen deflagration loads. The analysis addressed many nonlinearities and appealed to a strain-based failure criteria. The model used to predict the global response of the tank was not refined enough to confidently predict local peak strains. Strain concentration factors were applied at structural discontinuities that were based on steel-lined reinforced-concrete containment studies. The discontinuities included large penetrations, small penetrations, springline geometries, stud/liner connections, and the {1/2} inch to 3/8 inch liner thickness transition. The only tank specific strain concentration factor applied in the evaluation was for the {1/2} inch to 3/8 inch liner thickness change in the dome. Review of the tank drawings reveals the possibility that a 4 inches Sch. 40 pipe penetrates the dome thickness transition region. It is not obvious how to combine the strain concentration factors for a small penetration with that of a thickness transition to arrive at a composite strain concentration factor. It is the goal of this effort to make an approximate determination of the relative significance of the 4 inch penetration and the {1/2} inch to 3/8 inch thickness transition in the 241-SY-101 dome geometry. This is accomplished by performing a parametric study with three general finite-element models. The first represents the thickness transition only, the second represents a 4 inch penetration only, and the third combines the thickness transition with a penetration model.

  19. Structural analysis of multiport riser 5A installation on tank 241SY101

    SciTech Connect

    Strehlow, J.P.

    1994-09-16

    The Tank 101-SY multiport riser assembly in the 241-SY-101 waste tank will replace the existing 42 inch riser with four smaller ports. Each smaller port can be used independently to access the tank interior with equipment and instruments needed to mitigate the concentration of hydrogen in the tank. This document provides a design report on the structural evaluation of the multiport riser assembly as well as its anchorage. The multiport riser assembly is a steel structure installed directly above the 42-inch riser and sealed at the existing riser flange. The assembly is structurally supported by the concrete pad placed around the 42 inch riser. The multiport riser assembly will provide two 8-inch penetrations, one 12-inch penetration and one 24-inch penetration. Each penetration will have a shielding plate. These penetrations will be used to insert equipment such as a sonic probe into the tank. In addition to normal loads, non-reactor Safety Class 1 structures, systems and components are to withstand the effects of extreme environmental loads including Design Basis Earthquake (DBE), Design Basis Wind (DBW), Design Basis Flood, Volcanic Eruptions and other abnormal loads considered on a case by case basis. Non-reactor Safety Class 2, 3 and 4 structures, systems and components are those that are not Safety Class 1 and are respectively specified as onsite safety related, occupational safety related and non-safety related items. The 241-SY-101 tank is considered as a non-reactor Safety Class 1 structure. The multiport riser assembly is considered as a non-reactor Safety Class 2 structure since it serves to contain the radioactive and toxic materials under normal operating conditions. However, the pressure relief doors provided on the assembly are considered as Safety Class 1 structures.

  20. Assessment of Tank 241-S-112 Liquid Waste Mixing in Tank 241-SY-101

    SciTech Connect

    Onishi, Yasuo; Trent, Donald S.; Wells, Beric E.; Mahoney, Lenna A.

    2003-10-01

    The objectives of this study were to evaluate mixing of liquid waste from Tank 241-S-112 with waste in Tank 241-SY-101 and to determine the properties of the resulting waste for the cross-site transfer to avoid potential double-shell tank corrosion and pipeline plugging. We applied the time-varying, three-dimensional computer code TEMPEST to Tank SY-101 as it received the S-112 liquid waste. The model predicts that temperature variations in Tank SY-101 generate a natural convection flow that is very slow, varying from about 7 x 10{sup -5} to 1 x 10{sup -3} ft/sec (0.3 to about 4 ft/hr) in most areas. Thus, natural convection would eventually mix the liquid waste in SY-101 but would be very slow to achieve nearly complete mixing. These simulations indicate that the mixing of S-112 and SY-101 wastes in Tank SY-101 is a very slow process, and the density difference between the two wastes would further limit mixing. It is expected to take days or weeks to achieve relatively complete mixing in Tank SY-101.

  1. Laboratory testing of ozone oxidation of Hanford Site waste from Tank 241-SY-101

    SciTech Connect

    Delegard, C.H.; Stubbs, A.M.; Bolling, S.D.

    1993-12-14

    Ozone was investigated as a reagent to oxidize and destroy organic species present in simulated and genuine waste from Hanford Site Tank 241-SY-101 (Tank 101-SY). Two high-shear mixing apparatus were tested to perform the gas-to-solution mass transfer necessary to achieve efficient use of the ozone reagent. Oxidations of nitrite (to form nitrate) and organic species were observed. The organics oxidized to form carbonate and oxalate as well as nitrate and nitrogen gas from nitrogen associated with the organic. oxidations of metal species also were observed directly or inferred by solubilities. The chemical reaction stoichiometries were consistent with reduction of one oxygen atom per ozone molecule. Acetate, oxalate, and formate were found to comprise about 40% of the genuine waste`s total organic carbon (TOC) concentration. Ozonation was found to be chemically feasible for destroying organic species (except oxalate) present in the wastes in Tank 101-SY. The simulated waste formulation used in these studies credibly modelled the ozonation behavior of the genuine waste.

  2. Numerical simulation of Hanford Tank 241-SY-101 jet initiated fluid dynamics

    SciTech Connect

    Trent, D.S.; Michener, T.E.

    1994-12-31

    The episodic Gas Release Events (GREs) that have characterized the behavior of Hanford tank 241-SY-101 for the past several years are thought to result from the entrapment of gases generated in the settled solids, i.e., sludge, layer of the tank. Gases consisting of about 36% hydrogen by volume, which are generated by complicated and poorly understood radiological and chemical processes, are apparently trapped in the settled solids layer until their accumulation initiates a buoyant upset of this layer, abruptly releasing large quantities of gas. Once concept for preventing the gas accumulation is to mobilize the settled materials with jet mixing. It is suggested that continual agitation of the settled solids using a mixer pump would free the gas bubbles so that they could continually escape, thus mitigating the potential for accumulation of flammable concentrations of hydrogen in the tank dome space following a GRE. A pump test is planned to evaluate the effectiveness of the jet mixing mitigation concept. The pump will circulate liquid from the upper layer of the tank, discharging it through two horizontal jets located approximately 2{1/2} ft above the tank floor. To prepare for start-up of this pump test, technical, operation, and safety questions concerning an anticipated gas release were addressed by numerical simulation using the TEMPEST computer code. Simulations of the pump initiated gas release revealed that the amount of gas that could potentially be released to the tank dome space is very sensitive to the initial conditions assumed for the amount and distribution of gas in the sludge layer. Calculations revealed that within the assumptions regarding gas distribution and content, the pump might initiate a rollover--followed by a significant gas release--if the sludge layer contains more than about 13 to 14% gas distributed with constant volume fraction.

  3. Chemical and physical processes in Tank 241-SY-101: A preliminary report

    SciTech Connect

    Not Available

    1991-02-01

    Since 1942, chemical and radioactive waste have been stored in underground tanks at the Hanford Site. In March 1981 one of the double shell tanks, 241-SY-101 (called 101-SY), began venting large quantities of gas, primarily hydrogen and nitrous oxide. Because of the potential for explosion Westinghouse Hanford Company and the US Department of Energy realized the need for knowledge about the processes occurring in this tank that lead to generation of the gases. In June 1990, the Pacific Northwest Laboratory began assembling a Tank Waste Science Panel to develop a better understanding of the processes occurring the Tank 101-SY. This knowledge is necessary to provide a technically defensible basis for the safety analyses, which will allow the tank contents to be sampled, as well as for the future remediation of the tank and its contents. The Panel concluded that the data available on Tank 101-SY are insufficient to allow the critical chemical and physical processes giving rise to gas formation and release to be unambiguously identified. To provide the needed information the Panel recommends that Tank 101-SY by physically and chemically characterized as fully as possible and as expeditiously as safety considerations allow, and laboratory studies and modeling efforts be undertaken the chemical and physical processes involved in gas generation and release. Finally, the Panel recommends that no remediation steps be taken until there is a better understanding of the chemical and physical phenomena occurring in Tank 101-SY. Premature remediation steps may only serve to compound the problem. Furthermore, such steps may change the chemical and physical characteristics of the tank and prevent a true understanding of the phenomena involved. As a consequence, similar problems in other tanks on the site may not be adequately addressed. 17 refs., 3 figs., 1 tab.

  4. Effects of oxygen cover gas and NaOH dilution on gas generation in tank 241-SY-101 waste

    SciTech Connect

    Person, J.C.

    1996-05-30

    Laboratory studies are reported of gas generation in heated waste from tank 241-SY-101. The rates of gas generation and the compositions of product gas were measured. Three types of tests are compared. The tests use: undiluted waste, waste diluted by a 54% addition of 2.5 M NaOH, and undiluted waste with a reactive cover gas of 30% Oxygen in He. The gas generation rate is reduced by dilution, increased by higher temperatures (which determines activation energies), and increased by reactions of Oxygen (these primarily produce H{sub 2}). Gases are generated as reduction products oxidation of organic carbon species by nitrite and oxygen.

  5. Potential for Waste Stratification from Back-Dilution in Tank 241-SY-101

    SciTech Connect

    Antoniak, Z.I.; Meyer, P.A.

    1999-10-20

    Since late 1997, the floating crust layer in Hanford Tank 241-SY-101 (SY-101) has grown about two meters by gas accumulation. To reverse crust growth and reduce its retained gas volume, the waste in SY-101 will be diluted by transferring at least 300,000 gal of waste out of the tank and replacing it with water. In the fall of 1999, approximately 100,000 gal of this waste will be transferred into Tank SY-102; within a few days of that initial transfer, approximately 100,000 gal of water will be added to SY-101. This initial back-dilution is being planned to ensure that the base of the floating crust layer will be lifted away from the mixer pump inlet with minimal effect on the crust itself. The concern is that the added water will pool under the crust, so the resulting fluid mixture will be too light to lift the crust away from the mixer pump and dissolution at the crust base could cause unwanted gas release. To ensure sufficient mixing to prevent such stratification, water will be added near the tank bottom either through an existing sparge ring on the base of the mixer pump or through the dilution line at the inlet of the transfer pump. A number of simulations using the TEMPEST code showed that the mixing of the water and waste by this method is rapid, and the water does not pool under the crust. Although a density gradient is present, its magnitude is small compared with the difference between the slurry and water density. The result is essentially the same whether water is introduced at the base of the mixer pump or at the transfer pump. There is little effect of water flowrate up to the 500 gpm studied. In all cases, the minimum density remained above that required to float the crust and well above the density of saturated liquid. This indicates that the base of the crust will rise during back-dilution and there will be little or no dissolution of the crust base because the water will be close to saturation from the dissolution of solids in the mixed slurry.

  6. Effects of Crust Ingestion on Mixer Pump Performance in Tank 241-SY-101: Workshop Results

    SciTech Connect

    Brennen, C.E.; Stewart, C.W.; Meyer, P.A.

    1999-10-20

    In August 1999, a workshop was held at Pacific Northwest National Laboratory to discuss the effects of crust ingestion on mixer pump performance in Hanford Waste Tank 241-SY-101. The main purpose of the workshop was to evaluate the potential for crust ingestion to degrade mixing and/or damage the mixer pump. The need for a previously determined 12-inch separation between the top of the mixer pump inlet and the crust base was evaluated. Participants included a representative from the pump manufacturer, an internationally known expert in centrifugal pump theory, Hanford scientists and engineers, and operational specialists representing relevant fields of expertise. The workshop focused on developing an understanding of the pump design, addressing the physics of entrainment of solids and gases into the pump, and assessing the effects of solids and gases on pump performance. The major conclusions are summarized as follows: (1) Entrainment of a moderate amount of solids or gas from the crust should not damage the pump or reduce its lifetime, though mixing effectiveness will be somewhat reduced. (2) Air binding should not damage the pump. Vibrations due to ingestion of gas, solids, and objects potentially could cause radial loads that might reduce the lifetime of bearings and seals. However, significant damage would require extreme conditions not associated with the small bubbles, fine solids, and chunks of relatively weak material typical of the crust. (3) The inlet duct extension opening, 235 inches from the tank bottom, should be considered the pump inlet, not the small gap at 262 inches. (4) A suction vortex exists at the inlet of all pumps. The characteristics of the inlet suction vortex in the mixer pump are very hard to predict, but its effects likely extend upward several feet. Because of this, the current 12-inch limit should be replaced with criteria based on actual monitored pump performance. The most obvious criterion (in addition to current operational

  7. Transport of Tank 241-SY-101 Waste Slurry: Effects of Dilution and Temperature on Critical Pipeline Velocity

    SciTech Connect

    KP Recknagle; Y Onishi

    1999-06-15

    This report presents the methods and results of calculations performed to predict the critical velocity and pressure drop required for the two-inch pipeline transfer of solid/liquid waste slurry from underground waste storage Tank 241-SY-101 to Tank 241-SY- 102 at the Hanford Site. The effects of temperature and dilution on the critical velocity were included in the analysis. These analyses show that Tank 241-SY-101 slurry should be diluted with water prior to delivery to Tank 241-SY-102. A dilution ratio of 1:1 is desirable and would allow the waste to be delivered at a critical velocity of 1.5 ft/sec. The system will be operated at a flow velocity of 6 ft/sec or greater therefore, this velocity will be sufficient to maintain a stable slurry delivery through the pipeline. The effect of temperature on the critical velocity is not a limiting factor when the slurry is diluted 1:1 with water. Pressure drop at the critical velocity would be approximately two feet for a 125-ft pipeline (or 250-ft equivalent straight pipeline). At 6 ft/sec, the pressure drop would be 20 feet over a 250-ft equivalent straight pipeline.

  8. Ion exchange removal of cesium from simulated and actual supernate from Hanford tanks 241-SY-101 and 241-SY-103

    SciTech Connect

    Brown, G.N.; Bontha, J.R.; Carlson, C.D.

    1995-09-01

    Pacific Northwest Laboratory (PNL), in conjunction with the Process Chemistry and Statistics Section of Westinghouse Hanford Company (WHC), conducted this study as part of the Supernatant Treatment Development Task for the Initial Pretreatment Module (IPM) Applied Engineering Project. The study assesses the performance of the CS-100 ion exchange material for removing cesium from simulated and actual alkaline supernate from Hanford tanks 241-SY-101 and 241-SY-103. The objective of these experiments is to compare the cesium ion exchange loading and elution profiles of actual and simulated wastes. Specific experimental objectives include (1) demonstration of decontamination factors (DF) for cesium removal, 92) verification of simulant performance, (3) investigation of waste/exchanger chemistry, and (4) determination of the radionuclide content of the regenerated CS-100 resin prior to disposal.

  9. Analysis of several hazardous conditions for large transfer and back-dilution sequences in Tank 241-SY-101

    SciTech Connect

    CW Stewart; LA Mahoney; WB Barton

    2000-01-28

    The first transfer of 89 kgal of waste and back-dilution of 61 kgal of water in Hanford Tank 241-SY-101 was accomplished December 18--20, 1999. Limits were placed on the transfer and back-dilution volumes because of concerns about potential gas release, crust sinking, and degradation of mixer pump performance. Additional transfers and back-dilutions are being planned that will bring the total to 500 kgal, which should dissolve a large fraction of the solids in the tank and dilute it well beyond the point where significant gas retention can occur. This report provides the technical bases for removing the limits on transfer and back-dilution volume by evaluating the potential consequences of several postulated hazardous conditions in view of the results of the first campaign and results of additional analyses of waste behavior.

  10. A safety assessment for proposed pump mixing operations to mitigate episodic gas releases in tank 241-SY-101: Hanford Site,Richland, Washington

    SciTech Connect

    Lentsch, J.W.

    1996-07-01

    This safety assessment addresses each of the elements required for the proposed action to remove a slurry distributor and to install, operate, and remove a mixing pump in Tank 241-SY-101,which is located within the Hanford Site, Richland, Washington.The proposed action is required as part of an ongoing evaluation of various mitigation concepts developed to eliminate episodic gas releases that result in hydrogen concentrations in the tank dome space that exceed the lower flammability limit.

  11. Similarity analysis applied to the design of scaled tests of hydraulic mitigation methods for Tank 241-SY-101

    SciTech Connect

    Liljegren, L.M.

    1993-02-01

    The episodic gas releases from Tank 241-SY-101 (SY-101) pose a potential safety hazard. It is thought that gas releases occur because gases are generated and trapped in layers of settled solids located at the bottom of the tank. This document focuses on issues associated with testing of hydraulic mitigation technologies proposed for SY-101. The basic assumption underlying the concept of hydraulic mitigation is that mobilization or maintained suspension of the solids settled in the bottom of the tank wig prevent gas accumulation. Engineering of hydraulic technologies will require testing to determine the operating parameters required to mobilize the solids and to maintain these solids in suspension. Because full scale testing is extremely expensive (even when possible), scaled tests are needed to assess the merit of the proposed technologies and to provide data for numerical or analytical modeling. This research is conducted to support testing and evaluation of proposed hydraulic mitigation concepts only. The work here is oriented towards determining the jet velocities, nozzle sizes, and other operating parameters required to mobilize the settled solids in SY- 101 and maintain them in suspension.

  12. Human-machine interface (HMI) report for 241-SY-101 data acquisition [and control] system (DACS) upgrade study

    SciTech Connect

    Truitt, R.W.

    1997-10-22

    This report provides an independent evaluation of information for a Windows based Human Machine Interface (HMI) to replace the existing DOS based Iconics HMI currently used in the Data Acquisition and Control System (DACS) used at Tank 241-SY-101. A fundamental reason for this evaluation is because of the difficulty of maintaining the system with obsolete, unsupported software. The DACS uses a software operator interface (Genesis for DOS HMI) that is no longer supported by its manufacturer, Iconics. In addition to its obsolescence, it is complex and difficult to train additional personnel on. The FY 1997 budget allocated $40K for phase 1 of a software/hardware upgrade that would have allowed the old DOS based system to be replaced by a current Windows based system. Unfortunately, budget constraints during FY 1997 has prompted deferral of the upgrade. The upgrade needs to be performed at the earliest possible time, before other failures render the system useless. Once completed, the upgrade could alleviate other concerns: spare pump software may be able to be incorporated into the same software as the existing pump, thereby eliminating the parallel path dilemma; and the newer, less complex software should expedite training of future personnel, and in the process, require that less technical time be required to maintain the system.

  13. Thermal and combined thermal and radiolytic reactions involving nitrous oxide, hydrogen, nitrogen, and ammonia in contact with tank 241-SY-101 simulated waste

    SciTech Connect

    Bryan, S.A.; Pederson, L.R.

    1996-02-01

    Work described in this report was conducted at Pacific Northwest National Laboratory (PNNL) for the Flammable Gas Safety Project, the purpose of which is to develop information needed to support Westinghouse Hanford Company (WHC) in their efforts to ensure the safe interim storage of wastes at the Hanford Site. Described in this report are the results of tests to evaluate the rates of thermal and combined thermal and radiolytic reactions involving flammable gases in the presence of Tank 241-SY-101 simulated waste. Flammable gases generated by the radiolysis of water and by the thermal and radiolytic decomposition of organic waste constituents may themselves participate in further reactions. Examples include the decomposition of nitrous oxide to yield nitrogen and oxygen, the reaction of nitrous oxide and hydrogen to produce nitrogen and water, and the reaction of nitrogen and hydrogen to produce ammonia. The composition of the gases trapped in bubbles in the wastes might therefore change continuously as a function of the time that the gas bubbles are retained.

  14. Maximum First Transfer and Dilution Volumes for 241SY101

    SciTech Connect

    BARTON, W.B.

    1999-10-28

    This report discusses the solution to the following problem: what is the maximum waste transfer and dilution quantities and locations which can be allowed in the first transfer of waste from SY-101 given the following constraints? (1) The crust must float on the submerged waste (waste becomes less dense when diluted, eventually allowing crust to sink); (2) No credit is taken for the top dilution; (3) Addition of water to the bulk slurry through the transfer pump must be able to refloat the crust base to above 295 inches; (4) The margin between refloating to 295 inches and crust sinking must be at least 10,000 gallons; (5) The crust can't be thinned to less than 60 inches thick.

  15. Chemical mechanisms for gas generation in Tank 241-SY-101

    SciTech Connect

    Strachan, D.M.; Pederson, L.R.; Bryan, S.A.; Ashby, E.C.; Liotta, C.; Barefield, E.K.; Meisel, D.; Jonah, C.D.; Sauer, M.C. Jr.

    1993-08-01

    The mixing of wastes at Hanford over the years has led to several safety concerns. These safety concerns fall into six categories: wastes that generate flammable gasses or gas mixtures; wastes that contain high concentrations of ferrocyanides or tanks suspected of containing large amounts of ferrocyanides; wastes that contain greater than 3 wt % total organic carbon; wastes from which toxic or noxious vapors are suspected of emanating; wastes that contain high radiolytic heat; and wastes that may contain sufficient fissile material to pose a criticality concern. This report addresses the chemistry associated with the generation of flammable gases.

  16. Radioactive air emissions notice of construction 241-SY-101 crust growth near term mitigation

    SciTech Connect

    HOMAN, N.A.

    1999-04-12

    The following description and any attachments and references are provided to the Washington State Department of Health, Division of Radiation Protection, Air Emissions & Defense Waste Section as a notice of construction (NOC) in accordance with the Washington Administrative Code (WAC) 246-247, Radiation Protection - Air Emissions. The WAC 246-247-060, ''Applications, registration and licensing'', states ''This section describes the information requirements for approval to construct, modify, and operate an emission unit. Any NOC requires the submittal of the information listed in Appendix A.'' Appendix A (WAC 246-247-110), lists the requirements that must be addressed. Additionally, the following description, attachments and references are provided to the U.S. Environmental Protection Agency (EPA) as an NOC, in accordance with Title 40 Code of Federal Regulations (CFR), Part 61, ''National Emission Standards for Hazardous Air Pollutants.'' The information required for submittal to the EPA is specified in 40 CFR 61.07. The potential emissions from this activity are estimated to provide less than 0.1 mrem/year total effective dose equivalent to the hypothetical offsite maximally exposed individual, and commencement is needed within a short time frame. Therefore, this application is also intended to provide notification of the anticipated date of initial startup in accordance with the requirement listed in 40 CFR 61.09(a)(1), and it is requested that approval of this application will also constitute EPA acceptance of this 40 CFR 61.09(a)(1) notification. Written notification of the actual date of initial startup, in accordance with the requirement listed in 40 CFR 61.09(a)(2), will be provided at a later date.

  17. Pipeline Cross-Site Transfer Assessment for Tank 241-SY-101 Waste

    SciTech Connect

    Onishi, Yasuo; Wells, Beric E.; Hartley, Stacey A.; Cooley, Scott K.

    2002-02-20

    This study evaluated the feasibility of transferring waste now stored in Tank SY-101 in the 200 West Area of the Hanford Site to a storage tank in 200 East Area through a 6.2-mile-long, 3-inch-diameter stainless steel pipeline. Using the Wasp slurry transport model, the critical velocity and expected pressure drop were calculated to determine 1) whether current SY-101 waste can be transferred through the existing cross-site transfer pipeline without additional dilution and, if it is not possible, how much dilution is needed.

  18. Analysis of the flexible receiver lifting yoke and blast shield assembly. Tank 241SY101

    SciTech Connect

    Huang, F.H.

    1995-03-02

    The analysis of the lifting yoke and blast shield assembly considers the bending stress, weld strength, and resistance of the lug hole to tear out. The bending stress of the lifting lugs is evaluated to ensure that they meet the requirements of the American Institute for Steel Construction (AISC 1989). Also considered in the calculations is the capability of the thick lugs to withstand the weight of the pump together with that of the container and strongback during rotation to the horizontal position.

  19. Safety equipment list for the 241-SY-101 RAPID mitigation project

    SciTech Connect

    MORRIS, K.L.

    1999-06-29

    This document provides the safety classification for the safety (safety class and safety RAPID Mitigation Project. This document is being issued as the project SEL until the supporting authorization basis documentation, this document will be superseded by the TWRS SEL (LMHC 1999), documentation istlralized. Upon implementation of the authorization basis significant) structures, systems, and components (SSCS) associated with the 241-SY-1O1 which will be updated to include the information contained herein.

  20. Structural analysis of the equipment removal system for tank 241SY101

    SciTech Connect

    Mackey, T.C.

    1995-03-02

    The calculations documented in this report show that the ERS major components are structurally qualified to complete the objective, i.e., to install the removed equipment into a shipping container and transport and store the container at the Central Waste Complex (CWC). The analysis for the structural members of the ERS components considers live load with an impact factor of 125 % added to dead load. An allowable stress of one-third yield is used for all structural components carrying the load based on DOE-RL-92-36. Adherence to DOE-RL-92-36 is not a code requirement. However, the loads considered make this factor of safety appropriate. The calculations meet the strength requirements of the American Institute for Steel Construction (ASIC 1989) for all non-critical structural elements.

  1. Thermocouple module halt acceptance test report for tank 241-SY-101 DACS-1

    SciTech Connect

    Larsen, D.C.

    1998-03-10

    Testing was started on February 24, 1998 and completed on February 25, 1998. The completed procedure consists of 4 acceptance test sections, 6.1 through 6.4. Three test exceptions were identified during the procedure. The first test exception was determined to be unrelated to the ATP and unfortunate that the instrument failed during the ATP. The next two test exceptions were disposition as acceptable because the alarming functions worked correctly in identifying a problem when software communications were interrupted. The test was completed satisfactorily over 2 days. The remainder of the acceptance test report is the completed test procedure.

  2. Evaluation of 241 AN tank farm flammable gas behavior

    SciTech Connect

    Reynolds, D.A.

    1994-01-01

    The 241 AN Tank Farm tanks 241-AN-103, -104, and 105 are Flammable Gas Watch List tanks. Characteristics exhibited by these tanks (i.e., surface level drops, pressure increases, and temperature profiles) are similar to those exhibited by tank 241-SY-101, which is also a Watch List tank. Although the characteristics exhibited by tank 241-SY-101 are also present in tanks 241-AN-103, -104, and 105, they are exhibited to a lesser degree in the AN Tank Farm tanks. The 241 AN Tank Farm tanks have only small surface level drops, and the pressure changes that occur are not sufficient to release an amount of gas that would cause the dome space to exceed the lower flammability limit (LFL) for hydrogen. Therefore, additional restrictions are probably unnecessary for working within the 241 AN Tank Farm, either within the dome space of the tanks or in the waste.

  3. Final report of the TWRS Plant Implementation Team to review potential reactive component in tank 241-T-111 and methane in tank 241-SY-101 gas release event

    SciTech Connect

    Engelman, D.B.

    1994-02-01

    This is the final report of the results of a Tank Waste Remediation Systems Plant Implementation Team chartered by TWRS Operations, in response to a potential Unreviewed Safety Question (USQ) due to the discovery of a reactive component in waste tank 241-T-111 (T-111). Tank T-111, a non-Watch List single-shell tank, has no historical evidence of any potential safety problems. Core samples from tank T-111 were taken in 1991 and analyzed in 1992. The presence of uncharacterized exotherms was identified in the first three segments of two cores and reported to tank farm management in November 1993.

  4. 1/12-Scale mixing interface visualization and buoyant particle release tests in support of Tank 241-SY-101 hydrogen mitigation

    SciTech Connect

    Eschbach, E.J.; Enderlin, C.W.

    1993-10-01

    In support of tank waste safety programs, visualization tests were performed in the 1/12-scale tank facility, using a low-viscosity simulant. The primary objective of the tests was to obtain video records of the transient jet-sludge interaction. The intent is that these videos will provide useful qualitative data for comparison with model predictions. Two tests were initially planned: mixing interface visualization (MIV) and buoyant particle release (BPR). Completion of the buoyant particle release test was set aside in order to complete additional MIV tests. Rheological measurements were made on simulant samples before testing, and the simulant was found to exhibit thixotropic behavior. Shear vane measurements were also made on an in-situ analog of the 1/12-scale tank simulant. Simulant shear strength has been observed to be time dependent. The primary objective of obtaining video records of jet-sludge interaction was satisfied, and the records yielded jet location information which may be of use in completing model comparisons. The modeling effort is not part of this task, but this report also discusses test specific instrumentation, visualization techniques, and shear vane instrumentation which would enable improved characterization of jet-sludge interaction and simulant characteristics.

  5. Evaluation of high-level nuclear waste tanks having a potential flammable gas hazard

    SciTech Connect

    Johnson, G.D.; Barton, W.B.; Hill, R.C.; et al, Fluor Daniel Hanford

    1997-02-14

    In 1990 the U.S. Department of Energy declared an unreviewed safety question as a result of the behavior of tank 241-SY-101. This tank exhibited episodic releases of flammable gases that on a couple of occasions exceeded the lower flammability limit of hydrogen in air. Over the past six years a considerable amount of knowledge has been gained about the chemical and physical processes that govern the behavior of tank 241-SY-101 and the other tanks associated with a potential flammable gas hazard. This paper presents an overview of the current understanding of gas generation, retention, and release and covers the results of direct sampling of the tanks to determine the gas composition and the amount of stored gas.

  6. Thermal and combined thermal and radiolytic reactions involving nitrous oxide, hydrogen, and nitrogen in the gas phase; comparison of gas generation rates in supernate and solid fractions of Tank 241-SY-101 simulated waste

    SciTech Connect

    Bryan, S.A.; Pederson, L.R.

    1995-03-01

    This report summarizes progress made in evaluating me by which flammable gases are generated in Hanford double-shell tank wastes, based on the results of laboratory tests using simulated waste mixtures. Work described in this report. was conducted at Pacific Northwest Laboratory (PNL) for the Flammable Gas Safety Project, the purpose of which is to develop information needed to support Westinghouse Hanford Company (WHC) in their efforts to ensure the safe interim storage of wastes at the Hanford Site. This work is related to gas generation studies being performed at Georgia Institute of Technology (GIT), under subcontract to PNL, using simulated wastes, and to studies being performed at VMC using actual wastes.

  7. Level maintenance for Tank 101-SY mitigation-by-mixing test

    SciTech Connect

    Sobocinski, R.G.

    1994-11-16

    This document provides the procedure to be followed to implement the requirements of the Mixer Pump Long-Term Operations Plan for Tank 241-SY-101 Mitigation, WHC-SD-WM-PLN-081. The test is divided into 2 distinct sequences, named Single Position Pump Run and Tank Sweep. Instructions for all sequences are defined within the procedure. All safety requirements as defined in LA-UR-92-3196, A Safety Assessment for Proposed Mixing Operations to Mitigate Episodic Gas Releases in Tank 241-101-SY have been implemented into this procedure.

  8. The effect of dilution on the gas retention behavior of Tank 241-SY- 103 waste

    SciTech Connect

    Bredt, P.R.; Tingey, S.M.

    1996-01-01

    Twenty-five of the 177 underground waste storage tanks on the Hanford Site have been placed on the Flammable Gas watch list. These 25 tanks, containing high-level waste generated during plutonium and uranium processing, have been identified as potentially capable of accumulating flammable gases above the lower flammability limit (Babad et al. 1991). In the case of Tanks 241-SY-101 and 241-SY-103, it has been proposed that diluting the tank waste may mitigate this hazard (Hudson et al. 1995; Stewart et al. 1994). The effect of dilution on the ability of waste from Tank 241-SY-103 to accumulate gas was studied at Pacific Northwest National Laboratory. A similar study has been completed for waste from Tank 241-SY-101 (Bredt et al. 1995). Because of the additional waste-storage volume available in Tank 241-SY-103 and because the waste is assumed to be similar to that currently in Tank 241-SY-101, Tank 241-SY-103 became the target for a demonstration of passive mitigation through in-tank dilution. In 1994, plans for the in-tank dilution demonstration were deferred pending a decision on whether to pursue dilution as a mitigation strategy. However, because Tank 241-SY-103 is an early retrieval target, determination of how waste properties vary with dilution will still be required.

  9. Hybridization of ionic levels at metal surfaces

    NASA Astrophysics Data System (ADS)

    Kürpick, P.; Thumm, U.

    1998-09-01

    We investigated the hybridization of He+, Li2+, and Be3+ ionic levels and the creation of surface resonances for nuclear charges Z=2, 3, and 4 near an Al surface. Starting from a two-center basis set expansion with hydrogenic wave functions on the ion site and jellium wave functions in the metal half space, we calculate the self-energy for ion-surface system in the fixed-ion approximation. We obtain convergence by using a rather small set of bound ionic states. This ideally suits this method for the generation of adiabatic basis states that can be used in time-dependent close-coupling calculations for slow ion-surface collisions. We compare our resonance energies and widths with other theoretical approaches, discuss electronic density profiles, and analyze resonances in terms of Stark states.

  10. Chemically Induced Surface Evolutions with Level Sets

    Energy Science and Technology Software Center (ESTSC)

    2006-11-17

    ChISELS is used for the theoretical modeling of detailed surface chemistry and consomitant surface evolutions occurring during microsystem fabrication processes conducted at low pressures. Examples include physical vapor deposition (PVD), low pressure chemical vapor deposition (PECVD), and plasma etching. Evolving interfaces are represented using the level-set method and the evolution equations time integrated using a Semi-Lagrangian approach. A Ballistic transport model is employed to solve for the fluxes incident on each of the surface elements.more » Surface chemistry leading to etching or deposition is computed by either coupling to Surface Chemkin (a commercially available code) or by providing user defined subroutines. The computational meshes used are quad-trees (2-D) and oct-trees (3-D), constructed such that grid refinement is localized to regions near the surface interfaces. As the interface evolves, the mesh is dynamically reconstructed as needed for the grid to remain fine only around the interface. For parallel computation, a domain decomposition scheme with dynamic load balancing is used to distribute the computational work across processors.« less

  11. Chemically Induced Surface Evolutions with Level Sets

    SciTech Connect

    2006-11-17

    ChISELS is used for the theoretical modeling of detailed surface chemistry and consomitant surface evolutions occurring during microsystem fabrication processes conducted at low pressures. Examples include physical vapor deposition (PVD), low pressure chemical vapor deposition (PECVD), and plasma etching. Evolving interfaces are represented using the level-set method and the evolution equations time integrated using a Semi-Lagrangian approach. A Ballistic transport model is employed to solve for the fluxes incident on each of the surface elements. Surface chemistry leading to etching or deposition is computed by either coupling to Surface Chemkin (a commercially available code) or by providing user defined subroutines. The computational meshes used are quad-trees (2-D) and oct-trees (3-D), constructed such that grid refinement is localized to regions near the surface interfaces. As the interface evolves, the mesh is dynamically reconstructed as needed for the grid to remain fine only around the interface. For parallel computation, a domain decomposition scheme with dynamic load balancing is used to distribute the computational work across processors.

  12. The world's highest levels of surface UV.

    PubMed

    Cordero, Raul R; Seckmeyer, Gunther; Damiani, Alessandro; Riechelmann, Stefan; Rayas, Juan; Labbe, Fernando; Laroze, David

    2014-01-01

    Chile's northern Atacama Desert has been pointed out as one of the places on earth where the world's highest surface ultraviolet (UV) may occur. This area is characterized by its high altitude, prevalent cloudless conditions and relatively low total ozone column. Aimed at detecting those peak UV levels, we carried out in January 2013 ground-based spectral measurements on the Chajnantor Plateau (5100 m altitude, 23°00'S, 67°45'W) and at the Paranal Observatory (2635 m altitude, 24°37'S, 70°24'W). The UV index computed from our spectral measurements peaked at 20 on the Chajnantor Plateau (under broken cloud conditions) and at 16 at the Paranal Observatory (under cloudless conditions). Spectral measurements carried out in June 2005 at the Izaña Observatory (2367 m altitude, 28°18'N, 16°30'W) were used for further comparisons. Due to the differences in sun-earth separation, total ozone column, altitude, albedo, aerosols and clouds, peak UV levels are expected to be significantly higher at southern hemisphere sites than at their northern hemisphere counterparts. PMID:24202188

  13. An alternative to reduction of surface pressure to sea level

    NASA Technical Reports Server (NTRS)

    Deardorff, J. W.

    1982-01-01

    The pitfalls of the present method of reducing surface pressure to sea level are reviewed, and an alternative, adjusted pressure, P, is proposed. P is obtained from solution of a Poisson equation over a continental region, using the simplest boundary condition along the perimeter or coastline where P equals the sea level pressure. The use of P would avoid the empiricisms and disadvantages of pressure reduction to sea level, and would produce surface pressure charts which depict the true geostrophic wind at the surface.

  14. Challenges and methodology for safety analysis of a high-level waste tank with large periodic releases of flammable gas

    SciTech Connect

    Edwards, J.N.; Pasamehmetoglu, K.O.; White, J.R.; Stewart, C.W.

    1994-07-01

    Tank 241-SY-101, located at the Department of Energy Hanford Site, has periodically released up to 10,000 ft{sup 3} of flammable gas. This release has been one of the highest-priority DOE operational safety problems. The gases include hydrogen and ammonia (fuels) and nitrous oxide (oxidizer). There have been many opinions regarding the controlling mechanisms for these releases, but demonstrating an adequate understanding of the problem, selecting a mitigation methodology, and preparing the safety analysis have presented numerous new challenges. The mitigation method selected for the tank was to install a pump that would mix the tank contents and eliminate the sludge layer believed to be responsible for the gas retention and periodic releases. This report will describe the principal analysis methodologies used to prepare the safety assessment for the installation and operation of the pump, and because this activity has been completed, it will describe the results of pump operation.

  15. Beryllium surface levels in a military ammunition plant.

    PubMed

    Sanderson, Wayne T; Leonard, Stephanie; Ott, Darrin; Fuortes, Laurence; Field, William

    2008-07-01

    This study evaluated the presence of beryllium surface contamination in a U.S. conventional munitions plant as an indicator of possible past beryllium airborne and skin exposure and used these measurements to classify job categories by potential level of exposure. Surface samples were collected from production and nonproduction areas of the plant and at regional industrial reference sites with no known history of beryllium use. Surface samples of premoistened wiping material were analyzed for beryllium mass content using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and results expressed as micrograms of beryllium per 100 square centimeters (micro g/100 cm(2)). Beryllium was detected in 87% of samples collected at the munitions plant and in 72% of the samples collected at regional reference sites. Two munitions plant samples from areas near sanders and grinders were above 3.0 micro g/100 cm(2) (U.S. Department of Energy surface contamination limit). The highest surface level found at the reference sites was 0.44 micro g/100 cm(2). Workers in areas where beryllium-containing alloy tools were sanded or ground, but not other work areas, may have been exposed to airborne beryllium concentrations above levels encountered in other industries where metal work is conducted. Surface sampling provided information useful for categorizing munitions plant jobs by level of past beryllium airborne and skin exposure and, subsequently, for identifying employees within exposure strata to be screened for beryllium sensitization. PMID:18569510

  16. Performance evaluation of the Enraf-Nonius Model 872 radar gage

    SciTech Connect

    Peters, T.J.; Park, W.R.

    1992-12-01

    There are indications that the Enraf-Nonius Radar Gage installed in Tank 241-SY-101 may not be providing an accurate reading of the true surface level in the waste tank. The Pacific Northwest Laboratory (PNL) performed an initial study to determine the effect of the following items on the distance read by the gage: Tank riser; Material permittivity and conductivity Foam; Proportion of supernatant to solid material in the field of view of the instrument; Physical geometry of the supernatant and solid material changing in the field of view with respect to time; and Varying water content in the solid material. The results of the tests indicate that distance measured by the radar gage is affected by the permittivity, conductivity, and angle of the target surface. These parameters affect the complex input impedance of the signal received by the radar gage to measure the distance to the target. In Tank 101-SY, the radar gage is placed on top of a 12 in. diameter riser. The riser affects the field of view of the instrument, and a much smaller target surface is detected when the radar beam propagates through a riser. In addition, the riser acts as a waveguide, and standing waves are enhanced between the target surface and the radar gage. The result is a change in the level measured by the radar gage due to changing properties of the target surface even when the distance to the target does not change. The test results indicate that the radar will not detect dry crust or foam. However, if the crust or foam is stirred so that it becomes wet, then the crust or foam became detectable. The level read using the radar gage decreased as the moisture in the crust or foam evaporated.

  17. Doping level influence on chemical surface of diamond electrodes

    NASA Astrophysics Data System (ADS)

    Azevedo, A. F.; Baldan, M. R.; Ferreira, N. G.

    2013-04-01

    The modification of surface bond termination promoted by the doping level on diamond electrodes is analyzed. The films were prepared by hot filament chemical vapor deposition technique using the standard mixture of H2/CH4 with an extra H2 flux passing through a bubbler containing different concentrations of B2O3 dissolved in methanol. Diamond morphology and quality were characterized by scanning electron microscopy and Raman scattering spectroscopy techniques while the changes in film surfaces were analyzed by contact angle, cyclic voltammetry and synchrotron X-ray photoelectron spectroscopy (XPS). The boron-doped diamond (BDD) films hydrophobicity, reversibility, and work potential window characteristics were related to their physical properties and chemical surface, as a function of the doping level. From the Mott-Schottky plots (MSP) and XPS analyzes, for the lightly (1018 cm-3) and highly (1020 cm-3) BDD films, the relationship between the BDD electrochemical responses and their surface bond terminations is discussed.

  18. Fabrication and characterization of multi-level hierarchical surfaces.

    PubMed

    Bhushan, Bharat; Lee, Hyungoo

    2012-01-01

    A nanostructured surface may exhibit low adhesion or high adhesion depending upon fibrillar density, and it presents the possibility of realizing eco-friendly surface structures with desirable adhesion by mimicking the mechanics of fibrillar adhesive surfaces of biological systems. The current research uses a patterning technique to fabricate smart adhesion surfaces: one-, two- and three-level hierarchical synthetic adhesive structure surfaces with various fibrillar densities and diameters. The contact angles and contact angle hysteresis were measured to characterize the wettability. A conventional and a glass ball attached to an atomic force microscope (AFM) tip were used to obtain the adhesive forces via force-distance curves and to study the buckling behavior of a single fiber on the hierarchical structures. PMID:23285631

  19. A siphon gage for monitoring surface-water levels

    USGS Publications Warehouse

    McCobb, T.D.; LeBlanc, D.R.; Socolow, R.S.

    1999-01-01

    A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold regions cause discontinuity and inaccuracy in the data collected. Installation and field testing of a siphon gage using 0.75-in-diameter polyethylene tubing at Ashumet Pond in Falmouth, Massachusetts, demonstrated that the siphon gage can provide long-term data with a field effort and accuracy equivalent to measurement of ground-water levels at an observation well.A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold

  20. Probabilistic surface reconstruction of relative sea-level rise

    NASA Astrophysics Data System (ADS)

    Choblet, Gael; Husson, Laurent; Bodin, Thomas; Capdeville, Yann

    2013-04-01

    Relative sea level is shaped by multiple processes (mantle dynamic topography, plate tectonics, glacio-isostatic adjustment, present day melting of continental ice, anthropogenic causes…), most of which induce spatial gradients in relative sea level fluctuations. The evaluation of the global mean sea level rise is a also a key variable to decipher sea level evolution. Tide gauges represent the only mean to monitor sea-level rise on the scale of the 20th century, while the high quality satellite altimetry era is too short to be immune from short-term fluctuations. Tide gauge data compiled by the Permanent Service for the Mean Sea Level (PSMSL) converts into local estimates of sea level rise. Classically, these in situ observations are averaged spatially in order to infer the global mean sea level trend. However, the strongly heterogeneous distribution of tide gauges (e.g. very sparse in the Southern hemisphere) makes this approach relatively prone to uncertainties, given that sea level rise strongly varies geographically. Last, the societal consequences for coastal communities raise the prominent need for local (rather than global) sea level estimates. An alternative is therefore to provide a global surface reconstruction of relative sea level leading to both local variations and a better constrained global average. Here, we propose such a model from tide gauge records using a probabilistic scheme based on the reversible jump Markov chain Monte Carlo algorithm (as described by Bodin et al., JGR, 2012 for the example of the Australian Moho). This method allows to infer both model and parameter space so that not only the functions within the model but also the number of functions itself are free to vary. This is particulalry relevant to the case of tide gauges that are unevenly distributed on the surface of the Earth and whose record lengths are strongly variable. In addition, Bayesian statistics leads to a probabilistic representation (rather than a best fitting

  1. Efficient molecular surface generation using level-set methods.

    PubMed

    Can, Tolga; Chen, Chao-I; Wang, Yuan-Fang

    2006-12-01

    Molecules interact through their surface residues. Calculation of the molecular surface of a protein structure is thus an important step for a detailed functional analysis. One of the main considerations in comparing existing methods for molecular surface computations is their speed. Most of the methods that produce satisfying results for small molecules fail to do so for large complexes. In this article, we present a level-set-based approach to compute and visualize a molecular surface at a desired resolution. The emerging level-set methods have been used for computing evolving boundaries in several application areas from fluid mechanics to computer vision. Our method provides a uniform framework for computing solvent-accessible, solvent-excluded surfaces and interior cavities. The computation is carried out very efficiently even for very large molecular complexes with tens of thousands of atoms. We compared our method to some of the most widely used molecular visualization tools (Swiss-PDBViewer, PyMol, and Chimera) and our results show that we can calculate and display a molecular surface 1.5-3.14 times faster on average than all three of the compared programs. Furthermore, we demonstrate that our method is able to detect all of the interior inaccessible cavities that can accommodate one or more water molecules. PMID:16621636

  2. Automatic Measurement of Low Level Contamination on Concrete Surfaces

    SciTech Connect

    Tachibana, M.; Itoh, H.; Shimada, T.; Yanagihara, S.

    2002-02-28

    Automatic measurement of radioactivity is necessary for considering cost effectiveness in final radiological survey of building structures in decommissioning nuclear facilities. The RAPID (radiation measuring pilot device for surface contamination) was developed to be applied to automatic measurement of low level contamination on concrete surfaces. The RAPID has a capability to measure contamination with detection limit of 0.14 Bq/cm2 for 60Co in 30 seconds of measurement time and its efficiency is evaluated to be 5 m2/h in a normal measurement option. It was confirmed that low level contamination on concrete surfaces could be surveyed by the RAPID efficiently compared with direct measurement by workers through its actual application.

  3. Physics of the Be(0001) surface core-level spectrum

    SciTech Connect

    Feibelman, P.J.; Stumpf, R. )

    1994-12-15

    First-principles calculations for slabs as many as 13 layers thick show that the three surface core-level features observed on Be(0001) correspond to core-electron ionizations in its three outermost atomic layers. The calculations also imply that the experimental peak identified with core ionization in the bulk is a composite; theoretical core-ionization potentials for the fourth and deeper layers differ by as much as 90 meV. The sign and surprisingly large magnitudes of the Be(0001) surface core-level shifts (SCLS's) are attributed to unusually large surface-state contributions to the three outer layers' local densities of states. Both initial- and final-state effects are substantial in the SCLS's, and their contributions are additive.

  4. Sea level: measuring the bounding surfaces of the ocean.

    PubMed

    Tamisiea, Mark E; Hughes, Chris W; Williams, Simon D P; Bingley, Richard M

    2014-09-28

    The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. PMID:25157196

  5. Sea level: measuring the bounding surfaces of the ocean

    PubMed Central

    Tamisiea, Mark E.; Hughes, Chris W.; Williams, Simon D. P.; Bingley, Richard M.

    2014-01-01

    The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. PMID:25157196

  6. The effect of polarity and surface states on the Fermi level at III-nitride surfaces

    SciTech Connect

    Reddy, P; Bryan, I; Bryan, Z; Guo, W; Hussey, L; Collazo, R; Sitar, Z

    2014-09-28

    Surface states and their influence on the Fermi level at the surface of GaN and AlN are studied using x-ray photoelectron spectroscopy (XPS). The effect of polarity on surface electronic properties was studied. Accurate modeling of the valence band edge and comparison with XPS data revealed the presence of donor surface states at 1.4 eV and acceptor states at energies > 2.7 eV from the valence band in GaN. Al polar AlN showed acceptor states at energies > 3.3 eV. Density of acceptor surface states was estimated to be between 10(13) and 10(14) eV(-1) cm(-2) in both GaN and AlN. The shift in charge neutrality levels and barrier heights due to polarity and the density of surface states on AlN and GaN were estimated from XPS measurements. Theoretical modeling and comparison with XPS data implied full compensation of spontaneous polarization charge by charged surface states. Barrier height measurements also reveal a dependence on polarity with phi(metal-polar)>phi(non-polar)>phi(nitrogen-polar) suggesting that the N-polar surface is the most suitable for Ohmic contacts. (C) 2014 AIP Publishing LLC.

  7. Design review report for the SY-101 RAPID mitigation system

    SciTech Connect

    SCHLOSSER, R.L.

    1999-05-24

    This report documents design reviews conducted of the SY-101 Respond And Pump In Days (RAPID) Mitigation System. As part of the SY-101 Surface-Level-Rise Remediation Project, the SY-101 WID Mitigation System will reduce the potential unacceptable consequences of crust growth in Tank 241-SY-101 (SY-101). Projections of the crust growth rate indicate that the waste level in the tank may reach the juncture of the primary and secondary confinement structures of the tank late in 1999. Because of this time constraint, many design activities are being conducted in parallel and design reviews were conducted for system adequacy as well as design implementation throughout the process. Design implementation, as used in this design review report, is the final component selection (e.g., which circuit breaker, valve, or thermocouple) that meets the approved design requirements, system design, and design and procurement specifications. Design implementation includes the necessary analysis, testing, verification, and qualification to demonstrate compliance with the system design and design requirements. Design implementation is outside the scope of this design review. The design activities performed prior to detailed design implementation (i.e., system mission requirements, functional design requirements, technical criteria, system conceptual design, and where design and build contracts were placed, the procurement specification) have been reviewed and are within the scope of this design review report. Detailed design implementation will be controlled, reviewed, and where appropriate, approved in accordance with Tank Waste Remediation System (TWRS) engineering procedures. Review of detailed design implementation will continue until all components necessary to perform the transfer function are installed and tested.

  8. The half-filled Landau level and topological insulator surfaces

    NASA Astrophysics Data System (ADS)

    Senthil, T.

    The metallic state of the half-filled Landau level - described originally in pioneering work by Halperin , Lee, and Read as a liquid of composite fermions - was proposed recently by Son to be described by a particle-hole symmetric effective field theory distinct from that in the prior literature. This talk will develop a simple picture of the particle-hole symmetric composite fermion through a modification of older pictures as electrically neutral ``dipolar'' particles. This picture, and the proposed particle-hole symmetric theory, will be further substantiated through a recently developed deep connection between the half-filled Landau level and correlated surface states of certain three dimensional topological insulators. The phenomenology of composite fermi liquids (with or without particle-hole symmetry) will be revisited. It will be shown that their heat/electrical transport dramatically violates the conventional Wiedemann-Franz law but satisfies a modified one. References: 1. Chong Wang and T. Senthil, ``Half-filled Landau Level, Topological Insulator Surfaces, and Three Dimensional Quantum Spin Liquids,'' cond-mat arXiv:1507.08290 (2015).

  9. Surface core-level shifts and atomic coordination at a stepped W(110) surface

    SciTech Connect

    Riffe, D.M.; Kim, B.; Erskine, J.L. ); Shinn, N.D. )

    1994-11-15

    Core-level 4[ital f][sub 7/2] photoemission spectra have been measured from a single, bifacial W crystal, which has both a flat W(110) and a vicinal, stepped W(110) [W(320)] surface. This procedure reduces uncertainties in the quantitative description of peaks in the spectra from W(320). Various analyses, including nonlinear least-squares curve fitting, show that the average surface core-level shift (SCS) for W(320) is only [similar to][minus]140 meV, compared to [minus]310 meV for W(110) and that, at a maximum, only two of five terrace rows are isoelectronic to W(110) surface atoms. The absence of a large SCS for the step-edge atoms contradicts earlier interpretations of W(320) core-level spectra and departs significantly from expectations based on atomic-coordination models or tight-binding calculations of a bulk truncated surface. We suggest that systematic errors are responsible for the differences in reported core-level shifts for W(320). Implications of possible step-edge-driven atomic rearrangements are discussed.

  10. Contact Potentials, Fermi Level Equilibration, and Surface Charging.

    PubMed

    Peljo, Pekka; Manzanares, José A; Girault, Hubert H

    2016-06-14

    This article focuses on contact electrification from thermodynamic equilibration of the electrochemical potential of the electrons of two conductors upon contact. The contact potential difference generated in bimetallic macro- and nanosystems, the Fermi level after the contact, and the amount and location of the charge transferred from one metal to the other are discussed. The three geometries considered are spheres in contact, Janus particles, and core-shell particles. In addition, the force between the two spheres in contact with each other is calculated and is found to be attractive. A simple electrostatic model for calculating charge distribution and potential profiles in both vacuum and an aqueous electrolyte solution is described. Immersion of these bimetallic systems into an electrolyte solution leads to the formation of an electric double layer at the metal-electrolyte interface. This Fermi level equilibration and the associated charge transfer can at least partly explain experimentally observed different electrocatalytic, catalytic, and optical properties of multimetallic nanosystems in comparison to systems composed of pure metals. For example, the shifts in the surface plasmon resonance peaks in bimetallic core-shell particles seem to result at least partly from contact charging. PMID:27176729

  11. Molecular-level assemblies on metal oxide surfaces

    SciTech Connect

    Schoonover, J.R.; Bignozzi, C.; Meyer, T.

    1996-07-01

    This is the final report of a one-year, Laboratory-Directed Research and Development project at the Los Alamos National Laboratory (LANL). The objective of this project was to explore molecular-level assemblies based on polypyridyl transition metal complexes attached to metal oxide surfaces to provide the basis for applications such as energy conversion and electricity generation, photoremediation of hazardous waste, chemical sensors, and optical storage and photorefractive devices for communications and optical computing. We have elucidated the fundamental factors that determine the photochemistry and photophysics of a series of these photoactive inorganic complexes in solution and on metal oxide substrates by exploiting our unique transient laser capabilities. This data is being utilized to design and fabricate molecular-level photonic devices. The rich chemistry of transition metal polypyridyl complexes can be utilized to prepare molecular assemblies having well-defined redox or excited-state properties that can be finely tuned to produce desired materials properties. We plan to explore other novel applications such as photorefractive switches and optical sensors using this molecular engineering approach.

  12. Process for levelling film surfaces and products thereof

    DOEpatents

    Birkmire, Robert W.; McCandless, Brian E.

    1990-03-20

    Semiconductor films and photovoltaic devices prepared therefrom are provided wherein the semiconductor films have a specular surface with a texture less than about 0.25 micron greater than the average planar film surface and wherein the semiconductor films are surface modified by exposing the surface to an aqueous solution of bromine containing an acid or salt and continuing such exposure for a time sufficient to etch the surface.

  13. Process for leveling film surfaces and products thereof

    DOEpatents

    Birkmire, R.W.; McCandless, B.E.

    1990-03-20

    Semiconductor films and photovoltaic devices prepared therefrom are provided wherein the semiconductor films have a specular surface with a texture less than about 0.25 micron greater than the average planar film surface and wherein the semiconductor films are surface modified by exposing the surface to an aqueous solution of bromine containing an acid or salt and continuing such exposure for a time sufficient to etch the surface. 8 figs.

  14. Airborne Interferometry using GNSS Reflections for Surface Level Estimation

    NASA Astrophysics Data System (ADS)

    Semmling, Maximilian; Beyerle, Georg; Schön, Steffen; Stosius, Ralf; Gerber, Thomas; Beckheinrich, Jamila; Markgraf, Markus; Ge, Maorong; Wickert, Jens

    2013-04-01

    The interferometric use of GNSS reflections for ocean altimetry can fill the gap in coverage of ocean observations. Today radar altimeters are used for large scale ocean observations to monitor e.g. global sea level change or circulation processes like El Niño. Spacial and temporal resolution of a single radar altimeter, however, is insufficient to observe mesoscale ocean phenomena like large oceanic eddies that are important indicators of climate change. The high coverage expected for a spaceborne altimeter based on GNSS reflections stimulated investigations on according interferometric methods. Several airborne experiments have been conducted using code observations. Carrier observations have a better precision but are severely affected by noise and have mostly been used in ground-based experiments. A new interferometric approach is presented using carrier observations for airborne application. Implementing a spectral retrieval noise reduction is achieved. A flight experiment was conducted with a Zeppelin airship on 2010/10/12 over Lake Constance at the border between Austria, Germany and Switzerland. The lake surface with an area of 536km2 is suitable for altimetric study as its decimeter range Geoid undulations are well-known. Three GNSS receiver were installed on the airship. A Javad Delta receiver recording direct signals for navigation. The DLR G-REX receiver recording reflected signals for scatterometry and the GORS (GNSS Occultation Reflectometry Scatterometry) receiver recording direct and reflected signals for interferometry. The airship's trajectory is determined from navigation data with a precision better than 10cm using regional augmentation. This presentation focuses on the interferometric analysis of GORS observations. Ray tracing calculations are used to model the difference of direct and reflected signals' path. Spectral retrieval is applied to determine Doppler residuals of modelled path difference and interferometric observations. Lake level

  15. Maximum surface level and temperature histories for Hanford waste tanks

    SciTech Connect

    Flanagan, B.D.; Ha, N.D.; Huisingh, J.S.

    1994-09-02

    Radioactive defense waste resulting from the chemical processing of spent nuclear fuel has been accumulating at the Hanford Site since 1944. This waste is stored in underground waste-storage tanks. The Hanford Site Tank Farm Facilities Interim Safety Basis (ISB) provides a ready reference to the safety envelope for applicable tank farm facilities and installations. During preparation of the ISB, tank structural integrity concerns were identified as a key element in defining the safety envelope. These concerns, along with several deficiencies in the technical bases associated with the structural integrity issues and the corresponding operational limits/controls specified for conduct of normal tank farm operations are documented in the ISB. Consequently, a plan was initiated to upgrade the safety envelope technical bases by conducting Accelerated Safety Analyses-Phase 1 (ASA-Phase 1) sensitivity studies and additional structural evaluations. The purpose of this report is to facilitate the ASA-Phase 1 studies and future analyses of the single-shell tanks (SSTs) and double-shell tanks (DSTs) by compiling a quantitative summary of some of the past operating conditions the tanks have experienced during their existence. This report documents the available summaries of recorded maximum surface levels and maximum waste temperatures and references other sources for more specific data.

  16. PSA results for Hanford high level waste Tank 101-SY

    SciTech Connect

    MacFarlane, D.R.; Bott, T.F.; Brown, L.F.; Stack, D.W.; Kindinger, J.; Deremer, R.K.; Medhekar, S.R.; Mikschl, T.J.

    1993-10-01

    Los Alamos National Laboratory has performed a comprehensive probabilistic safety assessment (PSA) that includes consideration of external events for the weapons-production wastes stored in tank number 241-SY-101, commonly known as Tank 101-SY, as configured in December 1992. This tank, which periodically releases (``burps``) a gaseous mixture of hydrogen, nitrous oxide, ammonia, and nitrogen, was analyzed because of public safety concerns associated with the potential for release of radioactive tank contents should this gas mixture be ignited during one of the burps. In an effort to mitigate the burping phenomenon, an experiment is underway in which a large pump has been inserted into the tank to determine if pump-induced circulation of the tank contents will promote a slow, controlled release of the gases. This PSA for Tank 101-SY, which did not consider the pump experiment or future tank-remediation activities, involved three distinct tasks. First, the accident sequence analysis identified and quantified those potential accidents whose consequences result in tank material release. Second, characteristics and release paths for the airborne and liquid radioactive source terms were determined. Finally, the consequences, primarily onsite and offsite potential health effects resulting from radionuclide release, were estimated, and overall risk curves were constructed. An overview of each of these tasks and a summary of the overall results of the analysis are presented in the following sections.

  17. Test report for run-in acceptance testing of hydrogen mitigation retrieval Pump-3

    SciTech Connect

    Berglin, B.G.

    1997-08-15

    This report will provide the findings of the demonstration test conducted on the Double-Shell Tank (DST) 241-SY-101 HMR Pump-3 in accordance with WHC-SDWM-TP-434 ``Test plan for run-in acceptance testing of hydrogen mitigation/retrieval pump-3`` at the 400 Area Maintenance and Storage Facility (MASF) building from 7 June 1996 through 30 July 1996 per work package 4A-96-92/W. The DST 241-SY-101 hydrogen mitigation retrieval Pump-3 is a 200-HP submersible electric driven pump that has been modified for use in the DST 241-SY-101 containing mixed waste located in the 200W area. The pump has a motor driven rotation mechanism that allows the pump column to rotate through 355{degree}. Prior to operation, pre-operational checks were performed which included loop calibration grooming and alignment of instruments, learning how plumb HMR-3 assembly hung in a vertical position and bump test of the motor to determine rotation direction. The pump was tested in the MASF Large Diameter Cleaning Vessel (LDCV) with process water at controlled temperatures and levels. In addition, the water temperature of the cooling water to the motor oil heat exchanger was recorded during testing. A 480-volt source powered a Variable Frequency Drive (VFD). The VFD powered the pump at various frequencies and voltages to control speed and power output of the pump. A second VFD powered the oil cooling pump. A third VFD was not available to operate the rotational drive motor during the 72 hour test, so it was demonstrated as operational before and after the test. A Mini Acquisition and Control System (Mini-DACS) controls pump functions and monitoring of the pump parameters. The Mini-DACS consists of three computers, software and some Programmable Logic Controllers (PLC). Startup and shutdown of either the pump motor or the oil cooling pump can be accomplished by the Mini-DACS. When the pump was in operation, the Mini-DACS monitors automatically collects data electronically. However, some required data

  18. Measurement of local high-level, transient surface heat flux

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.

    1988-01-01

    This study is part of a continuing investigation to develop methods for measuring local transient surface heat flux. A method is presented for simultaneous measurements of dual heat fluxes at a surface location by considering the heat flux as a separate function of heat stored and heat conducted within a heat flux gage. Surface heat flux information is obtained from transient temperature measurements taken at points within the gage. Heat flux was determined over a range of 4 to 22 MW/sq m. It was concluded that the method is feasible. Possible applications are for heat flux measurements on the turbine blade surfaces of space shuttle main engine turbopumps and on the component surfaces of rocket and advanced gas turbine engines and for testing sensors in heat flux gage calibrators.

  19. Distributions of surface-layer buoyance versus lifting condensation level over a heterogeneous land surface

    SciTech Connect

    Schrieber, K.; Zhang, Qing; Stull, R.

    1996-04-15

    Onset and coverage of small cumulus clouds depend on the relative abundance of surface-layer air parcels possessing favorable buoyancy and moisture - two variables that are coupled through the surface energy budget. This abundance is described using a joint frequency distribution (JFD) as a function of virtual potential temperature {theta}{sub v} and height of the lifting condensation level z{sub LCL}. It is shown analytically that the shape and spread of this JFD depends on the ranges of Bowen ratios and solar forcings (albedoes, cloud shading, etc.) that exist within a domain of heterogeneous land use. To sample the character of such JFDs in the real atmosphere, a case study is presented using turbulence data gathered by aircraft flying in the surface layer of southwest France. This case study includes 4 days of clear skies during the Hydrologic Atmospheric Pilot Experiment (HAPEX) of 1986. The full flight track during HAPEX overflew a wide range of land use including evergreen forest, corn, vineyards, pastures, and irrigated fields over varied topography. The JFDs from these full tracks are found to be quite complex, being frequently multimodal with a convoluted perimeter. However, when a full track is broken into segments, each over a subdomain of quasi-homogeneous land use, the resulting segment JFDs are mono-modal with simpler topology. Such a characterization of JFDs provides guidance toward eventual subgrid cumulus parameterization in large-scale forecast models, with associated impacts in aviation forecasting, pollutant venting and chemical reactions, verticle dispersion and turbulence modulation, and radiation balance in climate-change models. 48 refs., 17 figs., 7 tabs.

  20. A Molecular-Level Account of the Antigenic Hantaviral Surface.

    PubMed

    Li, Sai; Rissanen, Ilona; Zeltina, Antra; Hepojoki, Jussi; Raghwani, Jayna; Harlos, Karl; Pybus, Oliver G; Huiskonen, Juha T; Bowden, Thomas A

    2016-05-01

    Hantaviruses, a geographically diverse group of zoonotic pathogens, initiate cell infection through the concerted action of Gn and Gc viral surface glycoproteins. Here, we describe the high-resolution crystal structure of the antigenic ectodomain of Gn from Puumala hantavirus (PUUV), a causative agent of hemorrhagic fever with renal syndrome. Fitting of PUUV Gn into an electron cryomicroscopy reconstruction of intact Gn-Gc spike complexes from the closely related but non-pathogenic Tula hantavirus localized Gn tetramers to the membrane-distal surface of the virion. The accuracy of the fitting was corroborated by epitope mapping and genetic analysis of available PUUV sequences. Interestingly, Gn exhibits greater non-synonymous sequence diversity than the less accessible Gc, supporting a role of the host humoral immune response in exerting selective pressure on the virus surface. The fold of PUUV Gn is likely to be widely conserved across hantaviruses. PMID:27117403

  1. A Molecular-Level Account of the Antigenic Hantaviral Surface

    PubMed Central

    Li, Sai; Rissanen, Ilona; Zeltina, Antra; Hepojoki, Jussi; Raghwani, Jayna; Harlos, Karl; Pybus, Oliver G.; Huiskonen, Juha T.; Bowden, Thomas A.

    2016-01-01

    Summary Hantaviruses, a geographically diverse group of zoonotic pathogens, initiate cell infection through the concerted action of Gn and Gc viral surface glycoproteins. Here, we describe the high-resolution crystal structure of the antigenic ectodomain of Gn from Puumala hantavirus (PUUV), a causative agent of hemorrhagic fever with renal syndrome. Fitting of PUUV Gn into an electron cryomicroscopy reconstruction of intact Gn-Gc spike complexes from the closely related but non-pathogenic Tula hantavirus localized Gn tetramers to the membrane-distal surface of the virion. The accuracy of the fitting was corroborated by epitope mapping and genetic analysis of available PUUV sequences. Interestingly, Gn exhibits greater non-synonymous sequence diversity than the less accessible Gc, supporting a role of the host humoral immune response in exerting selective pressure on the virus surface. The fold of PUUV Gn is likely to be widely conserved across hantaviruses. PMID:27117403

  2. The perception of surface layout during low level flight

    NASA Technical Reports Server (NTRS)

    Perrone, John A.

    1991-01-01

    Although it is fairly well established that information about surface layout can be gained from motion cues, it is not so clear as to what information humans can use and what specific information they should be provided. Theoretical analyses tell us that the information is in the stimulus. It will take more experiments to verify that this information can be used by humans to extract surface layout from the 2D velocity flow field. The visual motion factors that can affect the pilot's ability to control an aircraft and to infer the layout of the terrain ahead are discussed.

  3. Atomic-level imaging, processing and characterization of semiconductor surfaces

    DOEpatents

    Kazmerski, L.L.

    1995-08-22

    A method for selecting and removing single specific atoms from a solid material surface uses photon biasing to break down bonds that hold the selected atom in the lattice and to reduce barrier effects that hold the atom from transferring to a probe. The photon bias is preferably light or other electromagnetic radiation with a wavelength and frequency that approximately matches the wave function of the target atom species to be removed to induce high energy, selective thermionic-like vibration. An electric field potential is then applied between the probe and the surface of the solid material to pull the atom out of the lattice and to transfer the atom to the probe. Different extrinsic atoms can be installed in the lattice sites that are vacated by the removed atoms by using a photon bias that resonates the extrinsic atom species, reversing polarity of the electric field, and blowing gas comprising the extrinsic atoms through a hollow catheter probe. 8 figs.

  4. Atomic-level imaging, processing and characterization of semiconductor surfaces

    DOEpatents

    Kazmerski, Lawrence L.

    1995-01-01

    A method for selecting and removing single specific atoms from a solid material surface uses photon biasing to break down bonds that hold the selected atom in the lattice and to reduce barrier effects that hold the atom from transferring to a probe. The photon bias is preferably light or other electromagnetic radiation with a wavelength and frequency that approximately matches the wave function of the target atom species to be removed to induce high energy, selective thermionic-like vibration. An electric field potential is then applied between the probe and the surface of the solid material to pull the atom out of the lattice and to transfer the atom to the probe. Different extrinsic atoms can be installed in the lattice sites that are vacated by the removed atoms by using a photon bias that resonates the extrinsic atom species, reversing polarity of the electric field, and blowing gas comprising the extrinsic atoms through a hollow catheter probe.

  5. Slurry growth, gas retention, and flammable gas generation by Hanford radioactive waste tanks: Synthetic waste studies, FY 1991

    SciTech Connect

    Bryan, S.A.; Pederson, L.R.; Ryan, J.L.; Scheele, R.D.; Tingey, J.M.

    1992-08-01

    Of 177 high-level waste storage tanks on the Hanford Site, 23 have been placed on a safety watch list because they are suspected of producing flammable gases in flammable or explosive concentrate. One tankin particular, Tank 241-SY-101 (Tank 101-SY), has exhibited slow increases in waste volume followed by a rapid decrease accompanied by venting of large quantities of gases. The purpose of this study is to help determine the processes by which flammable gases are produced, retained, and eventually released from Tank 101-SY. Waste composition data for single- and double-shell waste tanks on the flammable gas watch listare critically reviewed. The results of laboratory studies using synthetic double-shell wastes are summarized, including physical and chemical properties of crusts that are formed, the stoichiometry and rate ofgas generation, and mechanisms responsible for formation of a floating crust.

  6. Assessment of alternative mitigation concepts for Hanford flammable gas tanks

    SciTech Connect

    Stewart, C.W.; Schienbein, L.A.; Hudson, J.D.; Eschbach, E.J.; Lessor, D.L.

    1994-09-01

    This report provides a review and assessment of four selected mitigation concepts: pump jet mixing, sonic vibration, dilution, and heating. Though the relative levels of development of these concepts are quite different, some definite conclusions are made on their comparative feasibility. Key findings of this report are as follows. A mixer pump has proven to be a safe and effective active mitigation method in Tank 241-SY-101, and the authors are confident that mixer pumps will effectively mitigate other tanks with comparable waste configurations and properties. Low-frequency sonic vibration is also predicted to be effective for mitigation. Existing data cannot prove that dilution can mitigate gas release event (GRE) behavior. However, dilution is the only concept of the four that potentially offers passive mitigation. Like dilution, heating the waste cannot be proven with available information to mitigate GRE behavior. The designs, analyses, and data from which these conclusions are derived are presented along with recommendations.

  7. New Performance Levels for TPV Front Surface Filters

    NASA Astrophysics Data System (ADS)

    Rahmlow, Thomas D.; Lazo-Wasem, Jeanne E.; Gratrix, Edward J.; Fourspring, Patrick M.; DePoy, David M.

    2004-11-01

    Front surface spectral control filters significantly improve the efficiency of thermophotovoltaic (TPV) converters. Tandem filter designs for 0.52 and 0.60 eV cells were fabricated. Energy and angle weighted spectral efficiencies of ˜83% for the 0.52 eV application and ˜76% for the 0.60 eV applications were achieved with ˜78% angle weighted above bandgap transmission. Manufacturing demonstrations of both designs were completed with good yield. Design improvements were made using angle weighted spectral utilization and above bandgap transmission as refinement goals. Current development work addresses elimination of the plasma filter and alternate substrates.

  8. Probing the Doping level in Graphene Using Surface Plasmon Resonance.

    NASA Astrophysics Data System (ADS)

    Alam, Kamrul; Li, Yang; Bao, Jiming

    2015-03-01

    The present work describes an investigation of the electrochemically doped large area CVD grown graphene by using surface plasmon resonance (SPR). As graphene was doped electrochemically its conductance changes based on electron and hole concentration, that have an effect on its permittivity which has influence on the refractive index. We have used SPR angle interrogation scheme, generally known as Kretschmann configuration, to detect this change in refractive index of graphene as a shift in the angle of the SPR curve. To verify our results we have use Raman spectroscopy of the graphene-Au hybrid sample that was used for SPR measurement. Shift in the G peak signifies that graphene is doped electrochemically which is also in agreement with the shift in the angle of the SPR curve.

  9. Model Study of Ozone Levels Over Snow-Covered Surfaces

    NASA Astrophysics Data System (ADS)

    Sandoval, A. E.; Jacobson, M. Z.

    2001-12-01

    A column gas-aerosol-radiative model is used to simulate chemistry and radiation in and above snowpack at mid-latitudes and over the Arctic. Fifty vertical layers are modeled, the lowest of which represent the upper 15 cm of the snowpack. Snow layers are treated as dense aerosol layers with the physical and optical properties of snow. Aqueous phase and heterogeneous reactions thought to occur in the snowpack are represented as reactions on the aerosol surface. Model simulations include analysis of (1) the spectral UV radiation extinction in the snowpack, (2) chemistry over the snowpack, including snowpack release of NOx and H2O2 and ozone reduction and its susceptibility to the presence of aldehydes and bromine, (3) and the effect of soot in snow on chemistry, UV extinction, and local energy balance. Model predictions are compared to measurements of UV fluxes and ozone over snow.

  10. Contingency plan for deployment of the void fraction instrument in Tank 241-AY-102

    SciTech Connect

    CONNER, J.M.

    1999-02-24

    High-heat producing sludge from tank 241-C-106 will be sluiced and transferred to tank 241-AY-102 beginning in October 1998. Safety analyses have postulated that after retrieval, the waste in 241-AY-102 may generate and retain unsafe levels of flammable gases (Noorani 1998, Pasamebmetoglu etal. 1997). Unsafe levels of retained gas are not expected, but cannot be ruled out because of the large uncertainty in the gas generation and retention rates. The Tank Waste Remediation System Basis for Interim Operation (Noorani 1998) identifies the need for a contingency plan to add void fraction monitoring to tank 241-AY-102 within 2 weeks of the identification of flammable gas buildup that would warrant monitoring. The Tank 241-C-106 Waste Retrieval Sluicing System Process Control Plan (Carothers et al. 1998) committed to providing a contingency plan for deployment of the void fraction instrument (VFI) in tank 241-AY-102. The VFI determines the local void fraction of the waste by compressing a waste sample captured in a gas-tight test chamber. The sample chamber is mounted on the end of a 76-cm (2.5-ft) arm that can be rotated from vertical to horizontal when the instrument is deployed. Once in the waste, the arm can be positioned horizontally and rotated to sample in different areas below the riser. The VFI is deployed using a crane. The VFI has been deployed previously in 241-AW, 241-AN, and 241-SY tank farms, most recently in tank 241-SY-101 in June and July 1998. An additional test in tank 241-SY-101 is planned in September 1998. Operating instructions for the VFI are included in the Void Fraction Instrument Operation and Maintenance Manual (Pearce 1994).

  11. System Design Description for the SY-101 Hydrogen Mitigation Test Project Data Acquisition and Control System (DACS-1)

    SciTech Connect

    ERMI, A.M.

    2000-01-24

    This document describes the hardware and software of the computer subsystems for the Data Acquisition and Control System (DACS) used in mitigation tests conducted on waste tank 241-SY-101 at the Hanford Nuclear Reservation.

  12. Computer system design description for the spare pump mini-dacs data acquisition and control system

    SciTech Connect

    Vargo, G.F. Jr.

    1994-09-29

    The attached document outlines the computer software design for the mini data acquisition and control system (DACS), that supports the testing of the spare pump for Tank 241-SY-101, at the maintenance and storage facility (MASF).

  13. Sea level and turbidity controls on mangrove soil surface elevation change

    NASA Astrophysics Data System (ADS)

    Lovelock, Catherine E.; Adame, Maria Fernanda; Bennion, Vicki; Hayes, Matthew; Reef, Ruth; Santini, Nadia; Cahoon, Donald R.

    2015-02-01

    Increases in sea level are a threat to seaward fringing mangrove forests if levels of inundation exceed the physiological tolerance of the trees; however, tidal wetlands can keep pace with sea level rise if soil surface elevations can increase at the same pace as sea level rise. Sediment accretion on the soil surface and belowground production of roots are proposed to increase with increasing sea level, enabling intertidal habitats to maintain their position relative to mean sea level, but there are few tests of these predictions in mangrove forests. Here we used variation in sea level and the availability of sediments caused by seasonal and inter-annual variation in the intensity of La Nina-El Nino to assess the effects of increasing sea level on surface elevation gains and contributing processes (accretion on the surface, subsidence and root growth) in mangrove forests. We found that soil surface elevation increased with mean sea level (which varied over 250 mm during the study) and with turbidity at sites where fine sediment in the water column is abundant. In contrast, where sediments were sandy, rates of surface elevation gain were high, but not significantly related to variation in turbidity, and were likely to be influenced by other factors that deliver sand to the mangrove forest. Root growth was not linked to soil surface elevation gains, although it was associated with reduced shallow subsidence, and therefore may contribute to the capacity of mangroves to keep pace with sea level rise. Our results indicate both surface (sedimentation) and subsurface (root growth) processes can influence mangrove capacity to keep pace with sea level rise within the same geographic location, and that current models of tidal marsh responses to sea level rise capture the major feature of the response of mangroves where fine, but not coarse, sediments are abundant.

  14. Ammonia in simulated Hanford double-shell tank wastes: Solubility and effects on surface tension

    SciTech Connect

    Norton, J.D.; Pederson, L.R.

    1994-09-01

    Radioactive and wastes left from defense materials production activities are temporarily stored in large underground tanks at the Hanford Site in south central Washington State (Tank Waste Science Panel 1991). Some of these wastes are in the form of a thick slurry (``double-shell slurry``) containing sodium nitrate, sodium nitrite, sodium aluminate, sodium hydroxide, sodium carbonate, organic complexants and buffering agents, complexant fragments and other minor components (Herting et al. 1992a; Herting et al. 1992b; Campbell et al. 1994). As a result of thermal and radiolytic processes, a number of gases are known to be produced by some of these stored wastes, including ammonia, nitrous oxide, nitrogen, hydrogen, and methane (Babad et al. 1991; Ashby et al. 1992; Meisel et al. 1993; Ashby et al. 1993; Ashby et al. 1994; Bryan et al. 1993; US Department of Energy 1994). Before the emplacement of a mixer pump, these gases were retained in and periodically released from Tank 241-SY-101, a double-shell tank at the Hanford Site (Babad et al. 1992; US Department of Energy 1994). Gases are believed to be retained primarily in the form of bubbles attached to solid particles (Bryan, Pederson, and Scheele 1992), with very little actually dissolved in the liquid. Ammonia is an exception. The relation between the concentration of aqueous ammonia in such concentrated, caustic mixtures and the ammonia partial pressure is not well known, however.

  15. Surface Landau levels and spin states in bismuth (111) ultrathin films

    NASA Astrophysics Data System (ADS)

    Du, Hongjian; Sun, Xia; Liu, Xiaogang; Wu, Xiaojun; Wang, Jufeng; Tian, Mingyang; Zhao, Aidi; Luo, Yi; Yang, Jinlong; Wang, Bing; Hou, J. G.

    2016-03-01

    The development of next-generation electronics is much dependent on the discovery of materials with exceptional surface-state spin and valley properties. Because of that, bismuth has attracted a renewed interest in recent years. However, despite extensive studies, the intrinsic electronic transport properties of Bi surfaces are largely undetermined due to the strong interference from the bulk. Here we report the unambiguous determination of the surface-state Landau levels in Bi (111) ultrathin films using scanning tunnelling microscopy under magnetic fields perpendicular to the surface. The Landau levels of the electron-like and the hole-like carriers are accurately characterized and well described by the band structure of the Bi (111) surface from density functional theory calculations. Some specific surface spin states with a large g-factor are identified. Our findings shed light on the exploiting surface-state properties of Bi for their applications in spintronics and valleytronics.

  16. Surface Landau levels and spin states in bismuth (111) ultrathin films

    PubMed Central

    Du, Hongjian; Sun, Xia; Liu, Xiaogang; Wu, Xiaojun; Wang, Jufeng; Tian, Mingyang; Zhao, Aidi; Luo, Yi; Yang, Jinlong; Wang, Bing; Hou, J. G.

    2016-01-01

    The development of next-generation electronics is much dependent on the discovery of materials with exceptional surface-state spin and valley properties. Because of that, bismuth has attracted a renewed interest in recent years. However, despite extensive studies, the intrinsic electronic transport properties of Bi surfaces are largely undetermined due to the strong interference from the bulk. Here we report the unambiguous determination of the surface-state Landau levels in Bi (111) ultrathin films using scanning tunnelling microscopy under magnetic fields perpendicular to the surface. The Landau levels of the electron-like and the hole-like carriers are accurately characterized and well described by the band structure of the Bi (111) surface from density functional theory calculations. Some specific surface spin states with a large g-factor are identified. Our findings shed light on the exploiting surface-state properties of Bi for their applications in spintronics and valleytronics. PMID:26964494

  17. Tomographic investigation of fermi level pinning at focused ion beam milled semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Wolf, D.; Lubk, A.; Lenk, A.; Sturm, S.; Lichte, H.

    2013-12-01

    Electron holography in the transmission electron microscope (TEM) offers the spatial and signal resolution for studying effects like Fermi level pinning or dopant concentration variations important for the design of modern electronic devices. To overcome the loss of information along the projection direction, surface effects, and surface damage due to TEM specimen preparation, we apply electron holographic tomography to analyze the 3D potential distribution of semiconductor samples prepared by focused-ion-beam. We observe mid-band gap pinning of the Fermi level at Si surfaces but valence band pinning at Ge surfaces. The pinning extends over tens of nanometers into the bulk.

  18. Effects of the atomic level shift in the Auger neutralization rates of noble metal surfaces

    PubMed Central

    Monreal, R.C.; Goebl, D.; Primetzhofer, D.; Bauer, P.

    2013-01-01

    In this work we compare characteristics of Auger neutralization of He+ ions at noble metal and free-electron metal surfaces. For noble metals, we find that the position of the energy level of He with respect to the Fermi level has a non-negligible influence on the values of the calculated Auger rates through the evaluation of the surface dielectric susceptibility. We conclude that even though our calculated rates are accurate, further theoretical effort is needed to obtain realistic values of the energy level of He in front of these surfaces. PMID:25843996

  19. Surface solar ultraviolet radiation for paleoatmospheric levels of oxygen and ozone

    NASA Technical Reports Server (NTRS)

    Levine, J. S.

    1980-01-01

    Many investigators have concluded that the level of solar ultraviolet radiation (200-300 nm) reaching the surface was a key parameter in the origin and evolution of life on earth. The level of solar ultraviolet radiation between 200 and 300 nm is controlled primarily by molecular absorption by ozone, whose presence is strongly coupled to the level of molecular oxygen. In this paper, a series of calculations is presented of the solar ultraviolet radiation reaching the surface for oxygen levels ranging from 0.0001 the present atmospheric level to the present level. The solar spectrum between 200 and 300 nm has been divided into 34 spectral intervals. For each spectral interval, the solar ultraviolet radiation reaching the earth's surface has been calculated by considering the attenuation of the incoming beam due to ozone and oxygen absorption. A one-dimensional photochemical model of the atmosphere was used for these calculations.

  20. Neuromuscular strategies for the transitions between level and hill surfaces during walking

    PubMed Central

    Gottschall, Jinger S.; Nichols, T. Richard

    2011-01-01

    Despite continual fluctuations in walking surface properties, humans and animals smoothly transition between terrains in their natural surroundings. Walking transitions have the potential to influence dynamic balance in both the anterior–posterior and medial–lateral directions, thereby increasing fall risk and decreasing mobility. The goal of the current manuscript is to provide a review of the literature that pertains to the topic of surface slope transitions between level and hill surfaces, as well as report the recent findings of two experiments that focus on the neuromuscular strategies of surface slope transitions. Our results indicate that in anticipation of a change in surface slope, neuromuscular patterns during level walking prior to a hill are significantly different from the patterns during level walking without the future change in surface. Typically, the changes in muscle activity were due to co-contraction of opposing muscle groups and these changes correspond to modifications in head pitch. In addition, further experiments revealed that the neck proprioceptors may be an initial source of feedback for upcoming surface slope transitions. Together, these results illustrate that in order to safely traverse varying surfaces, transitions strides are functionally distinct from either level walking or hill walking independently. PMID:21502127

  1. Full-Dimensional Potential Energy Surface and Ro-vibrational Levels of Dioxirane.

    PubMed

    Li, Jun; Guo, Hua

    2016-05-19

    A full-dimensional potential energy surface is developed for dioxirane based on a high-fidelity fit of ∼46,000 ab initio points at the CCSD(T)-F12a/AVTZ level. The ro-vibrational levels of dioxirane were computed using the MULTIMODE method on this potential energy surface, and the agreement with the available experimental microwave spectrum is quite satisfactory. In addition, dipole moment surfaces have been constructed from ab initio data, and they allow the prediction of the infrared (IR) spectrum. PMID:26422048

  2. A Discussion of SY-101 Crust Gas Retention and Release Mechanisms

    SciTech Connect

    SD Rassat; PA Gauglitz; SM Caley; LA Mahoney; DP Mendoza

    1999-02-23

    The flammable gas hazard in Hanford waste tanks was made an issue by the behavior of double-shell Tank (DST) 241-SY-101 (SY-101). Shortly after SY-101 was filled in 1980, the waste level began rising periodically, due to the generation and retention of gases within the slurry, and then suddenly dropping as the gases were released. An intensive study of the tank's behavior revealed that these episodic releases posed a safety hazard because the released gas was flammable, and, in some cases, the volume of gas released was sufficient to exceed the lower flammability limit (LFL) in the tank headspace (Allemann et al. 1993). A mixer pump was installed in SY-101 in late 1993 to prevent gases from building up in the settled solids layer, and the large episodic gas releases have since ceased (Allemann et al. 1994; Stewart et al. 1994; Brewster et al. 1995). However, the surface level of SY-101 has been increasing since at least 1995, and in recent months the level growth has shown significant and unexpected acceleration. Based on a number of observations and measurements, including data from the void fraction instrument (VFI), we have concluded that the level growth is caused largely by increased gas retention in the floating crust. In September 1998, the crust contained between about 21 and 43% void based on VFI measurements (Stewart et al. 1998). Accordingly, it is important to understand the dominant mechanisms of gas retention, why the gas retention is increasing, and whether the accelerating level increase will continue, diminish or even reverse. It is expected that the retained gas in the crust is flammable, with hydrogen as a major constituent. This gas inventory would pose a flammable gas hazard if it were to release suddenly. In May 1997, the mechanisms of bubble retention and release from crust material were the subject of a workshop. The evaluation of the crust and potential hazards assumed a more typical void of roughly 15% gas. It could be similar to percolati

  3. Analysis of sea level and sea surface temperature changes in the Black Sea

    NASA Astrophysics Data System (ADS)

    Betul Avsar, Nevin; Jin, Shuanggen; Kutoglu, Hakan; Erol, Bihter

    2016-07-01

    The Black Sea is a nearly closed sea with limited interaction with the Mediterranean Sea through the Turkish Straits. Measurement of sea level change will provide constraints on the water mass balance and thermal expansion of seawaters in response to climate change. In this paper, sea level changes in the Black Sea are investigated between January 1993 and December 2014 using multi-mission satellite altimetry data and sea surface temperature (SST) data. Here, the daily Maps of Sea Level Anomaly (MSLA) gridded with a 1/8°x1/8° spatial resolution from AVISO and the NOAA 1/4° daily Optimum Interpolation Sea Surface Temperature (OISST) Anomaly data set are used. The annual cycles of sea level and sea surface temperature changes reach the maximum values in November and January, respectively. The trend is 3.16±0.77 mm/yr for sea level change and -0.06±0.01°C/yr for sea surface temperature during the same 22-year period. The observed sea level rise is highly correlated with sea surface warming for the same time periods. In addition, the geographical distribution of the rates of the Black Sea level and SST changes between January 1993 and December 2014 are further analyzed, showing a good agreement in the eastern Black Sea. The rates of sea level rise and sea surface warming are larger in the eastern part than in the western part except in the northwestern Black Sea. Finally, the temporal correlation between sea level and SST time series are presented based on the Empirical Orthogonal Function (EOF) analysis.

  4. Origin of Fermi-level pinning at GaAs surfaces and interfaces

    NASA Astrophysics Data System (ADS)

    Colleoni, Davide; Miceli, Giacomo; Pasquarello, Alfredo

    2014-12-01

    Through first-principles simulation methods, we assign the origin of Fermi-level pinning at GaAs surfaces and interfaces to the bistability between the As-As dimer and two As dangling bonds, which transform into each other upon charge trapping. This defect is shown to be naturally formed both at GaAs surfaces upon oxygen deposition and in the near-interface substoichiometric oxide. Using electron-counting arguments, we infer that the identified defect occurs in opposite charge states. The Fermi-level pinning then results from the amphoteric nature of this defect which drives the Fermi level to its defect level. These results account for the experimental characterization at both GaAs surfaces and interfaces within a unified picture, wherein the role of As antisites is elucidated.

  5. Origin of Fermi-level pinning at GaAs surfaces and interfaces.

    PubMed

    Colleoni, Davide; Miceli, Giacomo; Pasquarello, Alfredo

    2014-12-10

    Through first-principles simulation methods, we assign the origin of Fermi-level pinning at GaAs surfaces and interfaces to the bistability between the As-As dimer and two As dangling bonds, which transform into each other upon charge trapping. This defect is shown to be naturally formed both at GaAs surfaces upon oxygen deposition and in the near-interface substoichiometric oxide. Using electron-counting arguments, we infer that the identified defect occurs in opposite charge states. The Fermi-level pinning then results from the amphoteric nature of this defect which drives the Fermi level to its defect level. These results account for the experimental characterization at both GaAs surfaces and interfaces within a unified picture, wherein the role of As antisites is elucidated. PMID:25372411

  6. Surface core-level binding energy shifts for MgO(100).

    PubMed

    Nelin, Connie J; Uhl, Felix; Staemmler, Volker; Bagus, Paul S; Fujimori, Yuichi; Sterrer, Martin; Kuhlenbeck, Helmut; Freund, Hans-Joachim

    2014-10-28

    Theoretical and experimental results for the surface core-level binding energy, BE, shifts, SCLS, for MgO(100) are presented and the anomalous O(1s) SCLS is interpreted in terms of the surface electronic structure. While the Mg(2p) surface BE shifts to a higher value than bulk by ≈1 eV as expected from the different surface and bulk Madelung potentials, the O(1s) SCLS is almost 0 rather than ≈-1 eV, expected from the Madelung potentials. The distortion of the surface atoms from the spherical symmetry of the bulk Mg and O atoms is examined by a novel theoretical procedure. The anomalous O SCLS is shown to arise from the increase of the effective size of surface O anions. PMID:25212984

  7. Multi-level polysilicon surface-micromachining technology: Applications and issues

    SciTech Connect

    Sniegowski, J.J.

    1996-08-01

    Polysilicon surface micromachining is a technology for manufacturing Micro-Electro-Mechanical Systems (MEMS) which has, as its basis, the manufacturing methods and tool sets used to manufacture the integrated electronic circuit. This paper describes a three-level mechanical-polysilicon surface-micromachining technology and includes a discussion of the advantages of this level of process complexity along with issues which affect device fabrication and performance. Historically, the primary obstacles to multi-level polysilicon fabrication were related to the severe wafer topography generated by the repetition of film depositions and etching. The introduction of Chemical Mechanical Polishing (CMP) to surface micromachining has largely removed these issues and opened significant avenues for device complexity. Several examples of three-level devices with the benefits of CMP are presented. Of primary hindrance to the widespread use of polysilicon surface micromachining, and in particular microactuation mechanisms, are issues related to the device surfaces. The closing discussion examines the potential of several latter and post-fabrication processes to circumvent or to directly alleviate the surface problems.

  8. Manufacturing microsystems-on-a-chip with 5-level surface micromachining technology

    SciTech Connect

    Sniegowski, J.; Rodgers, M.S.

    1998-05-01

    An agile microsystem manufacturing technology has been developed that provides unprecedented 5 levels of independent polysilicon surface-micromachine films for the designer. Typical surface-micromachining processes offer a maximum of 3 levels, making this the most complex surface-micromachining process technology developed to date. Leveraged from the extensive infrastructure present in the microelectronics industry, the manufacturing method of polysilicon surface-micromachining offers similar advantages of high-volume, high-reliability, and batch-fabrication to microelectromechanical systems (MEMS) as has been accomplished with integrated circuits (ICs). These systems, comprised of microscopic-sized mechanical elements, are laying the foundation for a rapidly expanding, multi-billion dollar industry 2 which impacts the automotive, consumer product, and medical industries to name only a few.

  9. Synergistic prevention of biofouling in seawater desalination by zwitterionic surfaces and low-level chlorination.

    PubMed

    Yang, Rong; Jang, Hongchul; Stocker, Roman; Gleason, Karen K

    2014-03-19

    Smooth, durable, ultrathin antifouling layers are deposited onto commercial reverse osmosis membranes without damaging them and they exhibit a fouling reduction. A new synergistic approach to antifouling, by coupling surface modification and drinking-water-level chlorination is enabled by the films' unique resistance against chlorine degradation. This approach substantially enhances longer-term fouling resistance compared with surface modification or chlorination alone, and can reduce freshwater production cost and its collateral toxicity to marine biota. PMID:24375685

  10. 5-level polysilicon surface micromachine technology: Application to complex mechanical systems

    SciTech Connect

    Rodgers, M.S.; Sniegowski, J.J.

    1998-06-01

    The authors recently reported on the development of a 5-level poly-ilicon surface micromachine fabrication process consisting of four levels of mechanical poly plus an electrical interconnect layer. They are now reporting on the first components designed for and fabricated in this process. These are demonstration systems, which definitively show that five levels of polysilicon provide greater performance, reliability, and significantly increased functionality. This new technology makes it possible to realize levels of system complexity that have so far only existed on paper, while simultaneously adding to the robustness of many of the individual subassemblies.

  11. Local-field corrections to surface and interface core-level shifts in insulators

    SciTech Connect

    Rotenberg, E. ); Olmstead, M.A. )

    1992-11-15

    We present a model for the extra-atomic contributions to core-level shifts in insulating thin films on polarizable substrates. The final-state shift is calculated from the screening-dependent local fields at a photoemitting atom and shown to be comparable to the initial-state Madelung potential shift in polar crystals. For Xe(111) films, our model completely accounts for experimental results. For NaCl(100) and CaF{sub 2}(111) surfaces, we present predictions of surface core-level shifts for simple bulk terminations. We discuss corrections which can be incorporated into our model.

  12. Development, Characterization, and Optimization of Protein Level in Date Bars Using Response Surface Methodology

    PubMed Central

    Nadeem, Muhammad; Salim-ur-Rehman; Muhammad Anjum, Faqir; Murtaza, Mian Anjum; Mueen-ud-Din, Ghulam

    2012-01-01

    This project was designed to produce a nourishing date bar with commercial value especially for school going children to meet their body development requirements. Protein level of date bars was optimized using response surface methodology (RSM). Economical and underutilized sources, that is, whey protein concentrate and vetch protein isolates, were explored for protein supplementation. Fourteen date bar treatments were produced using a central composite design (CCD) with 2 variables and 3 levels for each variable. Date bars were then analyzed for nutritional profile. Proximate composition revealed that addition of whey protein concentrate and vetch protein isolates improved the nutritional profile of date bars. Protein level, texture, and taste were considerably improved by incorporating 6.05% whey protein concentrate and 4.35% vetch protein isolates in date bar without affecting any sensory characteristics during storage. Response surface methodology was observed as an economical and effective tool to optimize the ingredient level and to discriminate the interactive effects of independent variables. PMID:22792044

  13. Development, characterization, and optimization of protein level in date bars using response surface methodology.

    PubMed

    Nadeem, Muhammad; Salim-ur-Rehman; Muhammad Anjum, Faqir; Murtaza, Mian Anjum; Mueen-ud-Din, Ghulam

    2012-01-01

    This project was designed to produce a nourishing date bar with commercial value especially for school going children to meet their body development requirements. Protein level of date bars was optimized using response surface methodology (RSM). Economical and underutilized sources, that is, whey protein concentrate and vetch protein isolates, were explored for protein supplementation. Fourteen date bar treatments were produced using a central composite design (CCD) with 2 variables and 3 levels for each variable. Date bars were then analyzed for nutritional profile. Proximate composition revealed that addition of whey protein concentrate and vetch protein isolates improved the nutritional profile of date bars. Protein level, texture, and taste were considerably improved by incorporating 6.05% whey protein concentrate and 4.35% vetch protein isolates in date bar without affecting any sensory characteristics during storage. Response surface methodology was observed as an economical and effective tool to optimize the ingredient level and to discriminate the interactive effects of independent variables. PMID:22792044

  14. Fusion of multi-sensory NDT data for reliable detection of surface cracks: Signal-level vs. decision-level

    NASA Astrophysics Data System (ADS)

    Heideklang, René; Shokouhi, Parisa

    2016-02-01

    We present and compare two different approaches for NDT multi-sensor data fusion at signal (low) and decision (high) levels. Signal-level fusion is achieved by applying simple algebraic rules to strategically post-processed images. This is done in the original domain or in the domain of a suitable signal transform. The importance of signal normalization for low-level fusion applications is emphasized in regard to heterogeneous NDT data sets. For fusion at decision level, we develop a procedure based on assembling joint kernel density estimation (KDE). The procedure involves calculating KDEs for individual sensor detections and aggregating them by applying certain combination rules. The underlying idea is that if the detections from more than one sensor fall spatially close to one another, they are likely to result from the presence of a defect. On the other hand, single-senor detections are more likely to be structural noise or false alarm indications. To this end, we design the KDE combination rules such that it prevents single-sensor domination and allows data-driven scaling to account for the influence of individual sensors. We apply both fusion rules to a three-sensor dataset consisting in ET, MFL/GMR and TT data collected on a specimen with built-in surface discontinuities. The performance of the fusion rules in defect detection is quantitatively evaluated and compared against those of the individual sensors. Both classes of data fusion rules result in a fused image of fewer false alarms and thus improved defect detection. Finally, we discuss the advantages and disadvantages of low-level and high-level NDT data fusion with reference to our experimental results.

  15. Hanford Tank Safety Project: Minutes of the Tank Waste Science Panel meeting, February 7--8, 1991

    SciTech Connect

    Strachan, D.M.

    1991-06-01

    The Tank Waste Science Panel met February 7--8, 1991, to review the latest data from the analyses of the October 24, 1990, gas release from Tank 241-SY-101 (101-SY) at Hanford; discuss the results of work being performed in support of the Hanford Tank Safety Project; and be briefed on the ferrocyanide issues included in the expanded scope of the Science Panel. The shapes of the gas release curves from the past three events are similar and correlate well with changes in waste level, but the correlation between the released volume of gas and the waste height is not as good. An analysis of the kinetics of gas generation from waste height measurements in Tank 101-SY suggests that the reaction giving rise to the gases in the tank is independent of the gas pressure and independent of the physical processes that give rise to the episodic release of the gases. Tank waste height data were also used to suggest that a floating crust formed early in the history of the tank and that the current crust is being made thicker in the eastern sector of the tank by repeated upheaval of waste slurry onto the surface. The correlation between the N{sub 2}O and N{sub 2} generated in the October release appears to be 1:1, suggesting a single mechanistic pathway. Analysis of other gas generation ratios, however, suggests that H{sub 2} and N{sub 2}O are evolved together, whereas N{sub 2} is from the air. If similar ratios are observed in planned radiolysis experiments are Argonne National Laboratory, radiolysis would appear to be generating most of the gases in Tank 101-SY. Data from analysis of synthetic waste crust using a dynamic x-ray diffractometer suggest that, in air, organics are being oxidized and liberating CO{sub 2} and NO{sub x}. Experiments at Savannah River Laboratory indicate that irradiation of solutions containing NO{sub 3} and organics can produce N{sub 2}O.

  16. Visually assessing the level of development and soil surface stability of cyanobacterially dominated biological soil crusts

    USGS Publications Warehouse

    Belnap, J.; Phillips, S.L.; Witwicki, D.L.; Miller, M.E.

    2008-01-01

    Biological soil crusts (BSCs) are an integral part of dryland ecosystems and often included in long-term ecological monitoring programs. Estimating moss and lichen cover is fairly easy and non-destructive, but documenting cyanobacterial level of development (LOD) is more difficult. It requires sample collection for laboratory analysis, which causes soil surface disturbance. Assessing soil surface stability also requires surface disturbance. Here we present a visual technique to assess cyanobacterial LOD and soil surface stability. We define six development levels of cyanobacterially dominated soils based on soil surface darkness. We sampled chlorophyll a concentrations (the most common way of assessing cyanobacterial biomass), exopolysaccharide concentrations, and soil surface aggregate stability from representative areas of each LOD class. We found that, in the laboratory and field, LOD classes were effective at predicting chlorophyll a soil concentrations (R2=68-81%), exopolysaccharide concentrations (R2=71%), and soil aggregate stability (R2=77%). We took representative photos of these classes to construct a field guide. We then tested the ability of field crews to distinguish these classes and found this technique was highly repeatable among observers. We also discuss how to adjust this index for the different types of BSCs found in various dryland regions.

  17. Assessment of heavy metal levels in surface sediments of estuaries and adjacent coastal areas in China

    NASA Astrophysics Data System (ADS)

    Liu, Xianbin; Li, Deliang; Song, Guisheng

    2016-05-01

    This article investigates the variations of contamination levels of heavy metals such as copper, lead, chromium, cadmium, zinc, arsenic, and mercury over time in surface sediments of the Changjiang River Estuary (CRE), Yellow River Estuary (YRE), Pearl River Estuary (PRE), and their adjacent coastal areas in China. The contamination factor (CF), pollution load index (PLI), and geoaccumulation index (I geo) are used to evaluate the quality of the surface sediments in the study areas. The results showed that the CRE, YRE, and their adjacent coastal areas were at a low risk of contamination in terms of heavy metals, while the PRE and its adjacent coastal area were at a moderate level. By comparison, the concentrations of heavy metals in the surface sediments of the YRE and its adjacent coastal area were relatively lower than those in the CRE, PRE, and their adjacent coastal areas.

  18. Cholesterol level affects surface charge of lipid membranes in saline solution

    PubMed Central

    Magarkar, Aniket; Dhawan, Vivek; Kallinteri, Paraskevi; Viitala, Tapani; Elmowafy, Mohammed; Róg, Tomasz; Bunker, Alex

    2014-01-01

    Cholesterol is an important component of all biological membranes as well as drug delivery liposomes. We show here that increasing the level of cholesterol in a phospholipid membrane decreases surface charge in the physiological environment. Through molecular dynamics simulation we have shown that increasing the level of cholesterol decreases Na+ ion binding. Complementary experimental ζ – potential measurements have shown a decreased ζ – potential with increasing cholesterol content, indicative of reduced surface charge. Both experiments and simulations have been carried out on both saturated 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and monounsaturated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes. This result is particularly important because membrane surface charge plays an important role in the interactions of biomembranes with peripheral membrane proteins and drug delivery liposomes with the immune system. PMID:24845659

  19. Spatially-varying surface roughness and ground-level air quality in an operational dispersion model.

    PubMed

    Barnes, M J; Brade, T K; MacKenzie, A R; Whyatt, J D; Carruthers, D J; Stocker, J; Cai, X; Hewitt, C N

    2014-02-01

    Urban form controls the overall aerodynamic roughness of a city, and hence plays a significant role in how air flow interacts with the urban landscape. This paper reports improved model performance resulting from the introduction of variable surface roughness in the operational air-quality model ADMS-Urban (v3.1). We then assess to what extent pollutant concentrations can be reduced solely through local reductions in roughness. The model results suggest that reducing surface roughness in a city centre can increase ground-level pollutant concentrations, both locally in the area of reduced roughness and downwind of that area. The unexpected simulation of increased ground-level pollutant concentrations implies that this type of modelling should be used with caution for urban planning and design studies looking at ventilation of pollution. We expect the results from this study to be relevant for all atmospheric dispersion models with urban-surface parameterisations based on roughness. PMID:24212233

  20. Non-Contact, No Wafer Preparation Deep Level Transient Spectroscopy Based on Surface Photovoltage

    NASA Astrophysics Data System (ADS)

    Lagowski, Jacek; Morawski, Andrzej; Edelman, Piotr

    1992-08-01

    We discuss a novel approach to Deep Level Transient Spectroscopy (DLTS) in which the emission of trapped minority carriers is analyzed employing the surface photovoltage (SPV) transient as measured in a non-contact manner on the native depletion barrier on semiconductor surfaces. Optical excitation is used as the trap-filling pulse. Experiments done on n-type GaAs demonstrate that the SPV-DLTS is suitable for wafer-scale, non-contact determination of deep level defects on semiconductor surfaces. The SPV approach can monitor emission rates up to 106 s-1 which is 102 to 103 above the limit of standard capacitance DLTS. The sensitivity of the method is comparable to that of the oplical capacitance DLTS.

  1. Alkyl-terminated Si(111) surfaces: A high-resolution, core level photoelectron spectroscopy study

    SciTech Connect

    Terry, J.; Linford, M.R.; Wigren, C.; Cao, R.; Pianetta, P.; Chidsey, C.E.

    1999-01-01

    The bonding of alkyl monolayers to Si(111) surfaces has been studied with high-resolution core level photoelectron spectroscopy (PES). Two very different wet-chemical methods have been used to prepare the alkyl monolayers: (i) Olefin insertion into the H{endash}Si bond of the H{endash}Si(111) surface, and (ii) replacement of Cl on the Cl{endash}Si(111) surface by an alkyl group from an alkyllithium reagent. In both cases, PES has revealed a C 1s component shifted to lower binding energy and a Si 2p component shifted to higher binding energy. Both components are attributed to the presence of a C{endash}Si bond at the interface. Along with photoelectron diffraction data [Appl. Phys. Lett. {bold 71}, 1056, (1997)], these data are used to show that these two synthetic methods can be used to functionalize the Si(111) surface. {copyright} {ital 1999 American Institute of Physics.}

  2. Observational evidence of temperature trends at two levels in the surface layer

    NASA Astrophysics Data System (ADS)

    Lin, X.; Pielke, R. A., Sr.; Mahmood, R.; Fiebrich, C. A.; Aiken, R.

    2015-09-01

    Long-term surface air temperatures at 1.5 m screen level over land are used in calculating a global average surface temperature trend. This global trend is used by the IPCC and others to monitor, assess, and describe global warming or warming hiatus. Current knowledge of near-surface temperature trends with respect to height, however, is limited and inadequately understood because surface temperature observations at different heights in the surface layer in the world are rare especially from a high-quality and long-term climate monitoring network. Here we use high-quality two-height Oklahoma Mesonet observations, synchronized in time, fixed in height, and situated in relatively flat terrain, to assess temperature trends and differentiating temperature trends with respect to heights (i.e., near-surface lapse rate trend) over the period 1997 to 2013. We show that the near-surface lapse rate has significantly decreased with a trend of -0.18 ± 0.03 °C (10 m)-1 decade-1 indicating that the 9 m height temperatures increased faster than temperatures at the 1.5 m screen level and conditions at the 1.5 m height cooled faster than at the 9 m height. However, neither of the two individual height temperature trends by themselves were statistically significant. The magnitude of lapse rate trend is greatest under lighter winds at night. Nighttime lapse rate trends were significantly more negative than daytime lapse rate trends and the average lapse rate trend was three times more negative under calm conditions than under windy conditions. Our results provide the first observational evidence of near-surface temperature changes with respect to height that could enhance the assessment of climate model predictions.

  3. Magnetic breakdown and Landau level spectra of a tunable double-quantum-well Fermi surface

    SciTech Connect

    Simmons, J.A.; Harff, N.E.; Lyo, S.K.; Klem, J.F.; Boebinger, G.S.; Pfeiffer, L.N.; West, K.W.

    1997-12-31

    By measuring longitudinal resistance, the authors map the Landau level spectra of double quantum wells as a function of both parallel (B{sub {parallel}}) and perpendicular (B{sub {perpendicular}}) magnetic fields. In this continuously tunable highly non-parabolic system, the cyclotron masses of the two Fermi surface orbits change in opposite directions with B{sub {parallel}}. This causes the two corresponding ladders of Landau levels formed at finite B{sub {perpendicular}} to exhibit multiple crossings. They also observe a third set of landau levels, independent of B{sub {parallel}}, which arise from magnetic breakdown of the Fermi surface. Both semiclassical and full quantum mechanical calculations show good agreement with the data.

  4. The effect of the sea breeze circulation on surface ozone levels at Wallops Island, Virginia

    NASA Technical Reports Server (NTRS)

    Parsons, C. L.; Williams, M. E.

    1979-01-01

    Surface measurements of windspeed, direction, and ozone concentration collected at Wallops Island, Virginia, during the summers of 1977 and 1978 are analyzed to study the effects of the dominant mesoscale sea breeze circulation on the local photochemical oxidant levels. A bimodality in the atmospheric dynamics is linked to systematic variations in ozone concentration. It is concluded that during certain phases of the two circulation modes, increased wind speed reduces the resistance of the earth's surface to the deposition of ozone, and decreased ozone concentration levels result. For other phases, light winds occur, signifying high resistance to deposition and high ozone levels. This modulation by the local dynamics is a major impediment for pollutant studies in coastal environments, especially those centering on transport, because it tends to mask other processes that may be occurring.

  5. The effect of leveling coatings on the atomic oxygen durability of solar concentrator surfaces

    NASA Technical Reports Server (NTRS)

    Degroh, Kim K.; Dever, Therese M.; Quinn, William F.

    1990-01-01

    Space power systems for Space Station Freedom will be exposed to the harsh environment of low earth orbit (LEO). Neutral atomic oxygen is the major constituent in LEO and has the potential of severely reducing the efficiency of solar dynamic power systems through degradation of the concentrator surfaces. Several transparent dielectric thin films have been found to provide atomic oxygen protection, but atomic oxygen undercutting at inherent defect sites is still a threat to solar dynamic power system survivability. Leveling coatings smooth microscopically rough surfaces, thus eliminating potential defect sites prone to oxidation attack on concentrator surfaces. The ability of leveling coatings to improve the atomic oxygen durability of concentrator surfaces was investigated. The application of a EPO-TEK 377 epoxy leveling coating on a graphite epoxy substrate resulted in an increase in solar specular reflectance, a decrease in the atomic oxygen defect density by an order of magnitude and a corresponding order of magnitude decrease in the percent loss of specular reflectance during atomic oxygen plasma ashing.

  6. Aerosols attenuating the solar radiation collected by solar tower plants: The horizontal pathway at surface level

    NASA Astrophysics Data System (ADS)

    Elias, Thierry; Ramon, Didier; Dubus, Laurent; Bourdil, Charles; Cuevas-Agulló, Emilio; Zaidouni, Taoufik; Formenti, Paola

    2016-05-01

    Aerosols attenuate the solar radiation collected by solar tower plants (STP), along two pathways: 1) the atmospheric column pathway, between the top of the atmosphere and the heliostats, resulting in Direct Normal Irradiance (DNI) changes; 2) the grazing pathway close to surface level, between the heliostats and the optical receiver. The attenuation along the surface-level grazing pathway has been less studied than the aerosol impact on changes of DNI, while it becomes significant in STP of 100 MW or more. Indeed aerosols mostly lay within the surface atmospheric layer, called the boundary layer, and the attenuation increases with the distance covered by the solar radiation in the boundary layer. In STP of 100 MW or more, the distance between the heliostats and the optical receiver becomes large enough to produce a significant attenuation by aerosols. We used measured aerosol optical thickness and computed boundary layer height to estimate the attenuation of the solar radiation at surface level at Ouarzazate (Morocco). High variabilities in aerosol amount and in vertical layering generated a significant magnitude in the annual cycle and significant inter-annual changes. Indeed the annual mean of the attenuation caused by aerosols over a 1-km heliostat-receiver distance was 3.7% in 2013, and 5.4% in 2014 because of a longest desert dust season. The monthly minimum attenuation of less than 3% was observed in winter and the maximum of more than 7% was observed in summer.

  7. Processing of Surface-NMR Data From Sites With High Noise Levels

    NASA Astrophysics Data System (ADS)

    Behroozmand, A. A.; Larsen, J. J.

    2015-12-01

    The applicability of surface NMR in investigations of groundwater is often limited by high noise levels in many areas of interest. In this paper we present measurements from a high noise level area in Ristrup, Denmark. Standard multichannel filtering techniques for noise reduction are inadequate for several data sets acquired in this area and surface-NMR signals cannot be resolved from the acquired data. With a careful assessment of the frequency content of the data, we show how a model-based approach can be used to subtract two harmonic noise components from the data and reliable surface-NMR data can be extracted from the noise-reduced data. Moreover, we show the impact of the proposed processing approaches on the inversion results and also present an example where the proposed methodology allows us to reveal and avoid an otherwise overlooked contamination of the reference coil signals with surface-NMR signal. The results of this study show that a careful processing of the data makes it possible to extract surface-NMR data in more places of interest.

  8. Surface damage correction, and atomic level smoothing of optics by Accelerated Neutral Atom Beam (ANAB) Processing

    NASA Astrophysics Data System (ADS)

    Walsh, M.; Chau, K.; Kirkpatrick, S.; Svrluga, R.

    2014-10-01

    Surface damage and surface contamination of optics has long been a source of problems for laser, lithography and other industries. Nano-sized surface defects may present significant performance issues in optical materials for deep UV and EUV applications. The effects of nanometer sized surface damage (scratches, pits, and organics) on the surface of optics made of traditional materials and new more exotic materials is a limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, zinc sulfide, BK7 and others presents a unique set of challenges. Exogenesis Corporation, using its proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and contamination and leaves many material surfaces with roughness typically around one angstrom. This process technology has been demonstrated on nonlinear crystals, and various other high-end optical materials. This paper describes the ANAB technology and summarizes smoothing results for various materials that have been processed with ANAB. All surface measurement data for the paper was produced via AFM analysis. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply normal forces associated with traditional polishing techniques. ANAB efficiently removes surface contaminants, nano-scale scratches, bumps and other asperities under low energy physical sputtering conditions as the removal action proceeds. ANAB may be used to remove a precisely controlled, uniform thickness of material without any increase of surface roughness, regardless of the total amount of material removed. The ANAB process does not

  9. Differential internalin A levels in biofilms of Listeria monocytogenes grown on different surfaces and nutrient conditions.

    PubMed

    Gilmartin, Niamh; Gião, Maria S; Keevil, Charles W; O'Kennedy, Richard

    2016-02-16

    Listeria monoctyogenes is a foodborne pathogen containing the surface protein, internalin A (InlA). The expression of this protein permits the invasion of L. monocytogenes into intestinal epithelial cells expressing the receptor E-cadherin, thus crossing the intestinal barrier and resulting in listerosis. The main aim of this work was to investigate InlA levels in different L. monocytogenes strains in both planktonic and sessile states using an anti-InlA antibody. Biofilms were grown in high and low nutrient environments on glass, stainless steel and polytetrafluoroethylene (PTFE). This study demonstrated that InlA levels varied greatly between strains and serotypes of L. monocytogenes. However, the serotypes 1/2a, 1/2b and 4b, associated with the largest number of outbreaks of listerosis consistently showed the highest InlA levels, regardless of nutrient content or planktonic or sessile state. Differences in InlA levels were also observed in biofilms grown on different surfaces such as glass, stainless steel and PTFE, with a significant reduction in InlA levels observed in biofilms on PTFE. Interestingly, although a large number of the total cells observed in biofilms formed in tap-water were non-cultivable, the virulence factor, InlA, was expressed at levels between 78 and 85%, thus indicating that these cells may still be virulent. A greater understanding of the factors that affect the levels of InlA on the surface of L. monocytogenes, is essential in the appreciation of the role of InlA in the persistence of biofilms containing L. monocytogenes and their potential to cause food borne disease. PMID:26724402

  10. Generation of topographic terrain models utilizing synthetic aperture radar and surface level data

    NASA Technical Reports Server (NTRS)

    Imhoff, Marc L. (Inventor)

    1991-01-01

    Topographical terrain models are generated by digitally delineating the boundary of the region under investigation from the data obtained from an airborne synthetic aperture radar image and surface elevation data concurrently acquired either from an airborne instrument or at ground level. A set of coregistered boundary maps thus generated are then digitally combined in three dimensional space with the acquired surface elevation data by means of image processing software stored in a digital computer. The method is particularly applicable for generating terrain models of flooded regions covered entirely or in part by foliage.

  11. Topology-optimized multiple-disk resonators obtained using level set expression incorporating surface effects.

    PubMed

    Fujii, Garuda; Ueta, Tsuyoshi; Mizuno, Mamoru; Nakamura, Masayuki

    2015-05-01

    Topology-optimized designs of multiple-disk resonators are presented using level-set expression that incorporates surface effects. Effects from total internal reflection at the surfaces of the dielectric disks are precisely simulated by modeling clearly defined dielectric boundaries during topology optimization. The electric field intensity in optimal resonators increases to more than four and a half times the initial intensity in a resonant state, whereas in some cases the Q factor increases by three and a half times that for the initial state. Wavelength-scale link structures between neighboring disks improve the performance of the multiple-disk resonators. PMID:25969226

  12. Application of the two-surface method for determining the sound power level of equipment in a power plant environment

    SciTech Connect

    Nuspl, S.P.

    1982-01-01

    The physical size and power requirements of some power plant equipment precludes any type of laboratory test for sound output, yet this information is often desired. Sound data usually is required on a free-field basis at some specified distance, or in terms of sound power level. As its name implies, the two-surface method of determining sound power level requires two enclosing measurement surfaces which are parallel to each other and are at some distance from the equipment under test. Average sound levels are determined from a series of grid measurements on each surface. These levels are derived using energy-averaging techniques and may represent overall, octave, or third-octave measurements. By calculating the difference in sound pressure levels and the area ratio of inner to outer surface, and by using information on hand (namely the inner surface area and average sound level on the inner surface), the sound power level can be calculated.

  13. A numerical approach to sound levels in near-surface refractive shadows.

    PubMed

    Cheinet, Sylvain

    2012-03-01

    The present study formulates a consistent method to simulate the outdoor, near-surface sound propagation through realistic refractive conditions. The correlated atmospheric stratification and turbulence properties are derived from standard meteorological quantities through flux-profile similarity relationships. The propagation of a monochromatic sound field is simulated in presence of the turbulence and stratification effects and an impedance ground. The propagation model uses a numerical solution of a second-order moment parabolic equation, which is introduced and evaluated. The so-formed coupled atmospheric-acoustic model is used to systematically investigate the sound levels in near-surface refractive shadows. In an illustrative propagation scenario, the shadow zone sound levels are predicted to show significant variations with the meteorological conditions. Specifically, the sound levels decrease with the adverse wind, as a consequence of enhanced mean upward refraction. Conversely, they increase with the absolute value of the surface heat flux, as a consequence of enhanced turbulence scattering. Implications for the assessment of the sound levels in shadow zones are discussed. PMID:22423692

  14. Mapping Hydrophobicity on the Protein Molecular Surface at Atom-Level Resolution

    PubMed Central

    Nicolau Jr., Dan V.; Paszek, Ewa; Fulga, Florin; Nicolau, Dan V.

    2014-01-01

    A precise representation of the spatial distribution of hydrophobicity, hydrophilicity and charges on the molecular surface of proteins is critical for the understanding of the interaction with small molecules and larger systems. The representation of hydrophobicity is rarely done at atom-level, as this property is generally assigned to residues. A new methodology for the derivation of atomic hydrophobicity from any amino acid-based hydrophobicity scale was used to derive 8 sets of atomic hydrophobicities, one of which was used to generate the molecular surfaces for 35 proteins with convex structures, 5 of which, i.e., lysozyme, ribonuclease, hemoglobin, albumin and IgG, have been analyzed in more detail. Sets of the molecular surfaces of the model proteins have been constructed using spherical probes with increasingly large radii, from 1.4 to 20 Å, followed by the quantification of (i) the surface hydrophobicity; (ii) their respective molecular surface areas, i.e., total, hydrophilic and hydrophobic area; and (iii) their relative densities, i.e., divided by the total molecular area; or specific densities, i.e., divided by property-specific area. Compared with the amino acid-based formalism, the atom-level description reveals molecular surfaces which (i) present an approximately two times more hydrophilic areas; with (ii) less extended, but between 2 to 5 times more intense hydrophilic patches; and (iii) 3 to 20 times more extended hydrophobic areas. The hydrophobic areas are also approximately 2 times more hydrophobicity-intense. This, more pronounced “leopard skin”-like, design of the protein molecular surface has been confirmed by comparing the results for a restricted set of homologous proteins, i.e., hemoglobins diverging by only one residue (Trp37). These results suggest that the representation of hydrophobicity on the protein molecular surfaces at atom-level resolution, coupled with the probing of the molecular surface at different geometric resolutions

  15. Level repulsion of GHz phononic surface waves in quartz substrate with finite-depth holes.

    PubMed

    Yeh, Sih-Ling; Lin, Yu-Ching; Tsai, Yao-Chuan; Ono, Takahito; Wu, Tsung-Tsong

    2016-09-01

    This paper presents numerical and experimental results on the level repulsion of gigahertz surface acoustic waves in an air/ST-cut quartz phononic structure with finite-depth holes. The colorful dispersion with the parameter of the in-plane (sagittal plane) ratio of polarization was adopted to determine the Rayleigh wave bandgap induced by the level repulsion. The results of numerical analyses showed that the frequency and width of the bandgap induced by the level repulsion strongly depend on the geometry of the air holes in the phononic structure. In the experiment, a pair of slanted interdigital transducers with frequency in the gigahertz range was designed and fabricated to generate and receive broadband Rayleigh waves, whereas the reactive ion etching process with electron-beam lithography was used to fabricate submicrometer phononic structures. The measured results of the bandgap induced by the level repulsion agreed favorably with the numerical prediction. PMID:27300272

  16. A kinematic and dynamic comparison of surface and underwater displacement in high level monofin swimming.

    PubMed

    Nicolas, Guillaume; Bideau, Benoit

    2009-08-01

    Fin swimming performance can be divided into underwater and surface water races. World records are about 10% faster for underwater swimming vs. surface swimming, but little is known about the advantage of underwater swimming for monofin swimming. Some authors reported that the air-water interface influences the kinematics and leads to a narrow vertical amplitude of the fin. On the one hand, surface swimming is expected to affect drag parameters (cross-sectional area (S) and active drag (AD)) when compared to underwater swimming. On the other hand, the surface swimming technique may also affect efficiency (eta(F)). The aim of this study is therefore to evaluate and compare drag parameters and efficiency during underwater and surface swimming. To this end, 12 international level monofin swimmers were measured during both underwater and surface swimming. Kinematic parameters (both dimensional and non-dimensional), eta(F) (calculated according to the Elongated-Body Theory), and AD (computed with Velocity Perturbation Method) were calculated for an underwater and a surface fin swimming trial, performed at maximal speed. As expected, results showed significantly lower velocities during surface swimming vs. underwater V(1,under) =2.5ms(-1) vs. V(1,surf) =2.36ms(-1), p<.01). Velocities during underwater and surface swimming were strongly correlated (r=.97, p<.01). Underwater swimming was also associated with higher vertical amplitudes of the fin compared to surface swimming (V(under) =0.55mvs. V(surf) )=0.46m, p<.01). Length-specific amplitudes (A(under)/L(b)) were in the order of 20% during underwater swimming as for undulating fish, and significantly higher than during surface swimming (A(surf)/L(b)=17%, p<.01). Efficiency for surface swimming was about 6% lower than for underwater swimming (eta(F,under) =0.79 vs. eta(F,surf) =0.74, p<.01). This decrease could be associated with an increase in swimming frequency for surface swimming (f (surf)=2.15Hz vs. f (under)=2.08Hz

  17. Spectral properties of thermal fluctuations on simple liquid surfaces below shot-noise levels.

    PubMed

    Aoki, Kenichiro; Mitsui, Takahisa

    2012-07-01

    We study the spectral properties of thermal fluctuations on simple liquid surfaces, sometimes called ripplons. Analytical properties of the spectral function are investigated and are shown to be composed of regions with simple analytic behavior with respect to the frequency or the wave number. The derived expressions are compared to spectral measurements performed orders of magnitude below shot-noise levels, which is achieved using a novel noise reduction method. The agreement between the theory of thermal surface fluctuations and the experiment is found to be excellent, elucidating the spectral properties of the surface fluctuations. The measurement method requires relatively only a small sample both spatially (few μm) and temporally (~20 s). The method also requires relatively weak light power (~0.5 mW) so that it has a broad range of applicability, including local measurements, investigations of time-dependent phenomena, and noninvasive measurements. PMID:23005425

  18. Exploring the core level shift origin of sulfur and thiolates on Pd(111) surfaces.

    PubMed

    Salvarezza, Roberto Carlos; Carro, Pilar

    2015-10-01

    Thiol molecules on planar metal surfaces are widely used for building sensing and electronic devices and also as capping agents to protect and to control the size and shape of nanoparticles. In the case of Pd the thiol molecules exhibit a complex behavior because C-S bond scission is possible, resulting in a significant amount of co-adsorbed S. Therefore identification of these species on Pd is a key point for many applications, a task that is usually achieved by XPS. Here we show, from DFT calculations, that the core level shift (CLS) of the S 2p binding energy (BE) of thiol and sulfur on different thiol-Pd(111) surface models strongly depends on the adsorbed or subsurface state of sulfur atoms. Our results reflect the complexity of S 2p BE behavior and contribute to understanding and reanalyzing the experimental data of thiolated Pd surfaces. PMID:26325179

  19. Reduction of the sonic boom level in supersonic aircraft flight by the method of surface cooling

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Chirkashenko, V. F.; Volkov, V. F.; Kharitonov, A. M.

    2013-12-01

    Based on the analysis of various aspects of creating a supersonic transport aircraft of the second generation, the necessity of developing unconventional active methods of sonic boom level reduction is demonstrated. Surface cooling is shown to exert a significant effect on formation of the disturbed flow structure up to large distances from the body by an example of a supersonic flow around a body of revolution. A method of reducing the intensity of the intermediate shock wave and excess pressure momentum near the body is proposed. This method allows the length of the reduced (by 50%) sonic boom level to be increased and the bow shock wave intensity in the far zone to be reduced by 12%. A possibility of controlling the process of formation of wave structures, such as hanging pressure shocks arising near the aircraft surface, is demonstrated. The action of the cryogenic mechanism is explained.

  20. Reduction of the sonic boom level in supersonic aircraft flight by the method of surface cooling

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Chirkashenko, V. F.; Volkov, V. F.; Kharitonov, A. M.

    2014-12-01

    Based on the analysis of various aspects of creating a supersonic transport aircraft of the second generation, the necessity of developing unconventional active methods of sonic boom level reduction is demonstrated. Surface cooling is shown to exert a significant effect on formation of the disturbed flow structure up to large distances from the body by an example of a supersonic flow around a body of revolution. A method of reducing the intensity of the intermediate shock wave and excess pressure momentum near the body is proposed. This method allows the length of the reduced (by 50%) sonic boom level to be increased and the bow shock wave intensity in the far zone to be reduced by 12%. A possibility of controlling the process of formation of wave structures, such as hanging pressure shocks arising near the aircraft surface, is demonstrated. The action of the cryogenic mechanism is explained.

  1. Direct Measurement of Surface Defect Level Distribution Associated with GaAs Antiphase Boundaries

    SciTech Connect

    Xu, Q.; Hsu, J.W.

    1999-01-01

    Using an electrostatic force microscope, we measure surface contact potential (SCP) variations across antiphase boundaries (APBs) on GaAs films grown on Ge substrates. The SCP at the APBs is consistently and reproducibly measured to be 30 mV higher than that at GaAs domains. This is due to Fermi levels being pinned at different surface states. The identical electrical behavior observed for all APBs indicates that they are the lowest energy {l_brace}110{r_brace} orientation. The sign of observed Fermi level shift is consistent with a prevalence of Ga-Ga bonds at real {l_brace}110{r_brace} APBs. {copyright} {ital 1999} {ital The American Physical Society}

  2. Definition and Development of Habitation Readiness Levels (HRLs) for Planetary Surface Habitats

    NASA Technical Reports Server (NTRS)

    Connolly, Janis H.; Toups, Larry

    2007-01-01

    One could argue that NASA has never developed a true habitat for a planetary surface, with only the Lunar Module from the 1960's-era Apollo Program providing for a sparse 2 person, 3 day capability. An integral part of NASA's current National Vision for Space Exploration is missions back to the moon and eventually to Mars. One of the largest leaps i11 lunar surface exploration beyond the Apollo lunar missions will be the conduct of these extended duration human missions. These missions could range from 30 to 90 days in length initially and may eventually range up to 500 days in length. To enable these extended duration human missions, probably the single-most important lunar surface element is the Surface Habitat. The requirements that must be met by the Surface Habitat will go far beyond the safety, performance and operational requirements of the Lunar Module, and NASA needs to develop a basis for making intelligent, technically correct habitat design decisions. This paper will discuss the possibilities of the definition and development of a Habitation Readiness Level (HRL) scale that might be mapped to current Technology Readiness Levels (TRLs) for technology development. HRLs could help measure how well a particular technology thrust is advanced by a proposed planetary habitat concept. The readiness level would have to be measured differently than TRLs, and may include such milestones as habitat design performance under simulated mission operations and constraints (including relevant field testing), functional allocation demonstrations, crew interface evaluation and post-occupancy evaluation. With many concepts for planetary habitats proposed over the past 20 years, there are many strategic technical challenges facing designers of planetary habitats that will support NASA's exploration of the moon and Mars. The systematic assessment of a variety of planetary habitat options will be an important approach and will influence the associated requirements for human

  3. Comparison of TOPEX sea surface heights and tide gauge sea levels

    NASA Technical Reports Server (NTRS)

    Mitchum, Gary T.

    1994-01-01

    TOPEX sea surface height data from the first 300 days of the mission are compared to sea level data from 71 tide gauges. The initial comparison uses sea surface height data processed according to standard procedures as defined in the users handbook. It is found that the median correlations for island and for coastal tide gauges are 0.53 and 0.42, respectively. The analogous root mean square (RMS) differences between the two data sets are 7.9 and 10.4 cm. The comparisons improve significantly when a 60-day harmonic is fit to the differences and removed. This period captures aliased M(sub 2) and S(sub 2) tidal energy that is not removed by the tide model. Making this correction and smoothing the sea surface height data over 25-km along-track segments results in median correlations of 0.58 and 0.46 for the islands and coastal stations, and median RMS differences of 5.8 and 7.7 cm, respectively. Removing once per revolution signals from the sea surface heights results in degraded comparisons with the sea levels. It is also found that a number of stations have poor comparisons due to propagating signals that introduce temporal lags between the altimeter and tide gauge time series. A final comparison is made by eliminating stations where this propagation effect is large, discarding two stations that are suspected to have problems with the sea level data, smoothing over 10-day intervals, and restricting attention to islands gauges. This results in a set of 552 data pairs that have a correlation of 0.66 and a RMS difference of 4.3 cm. The conclusion is that on timescales longer than about 10 days the RMS sea surface height errors are less than or of the order of several centimeters.

  4. Potassium-induced charge redistribution on Si(111) surfaces studied by core-level photoemission spectroscopy

    SciTech Connect

    Ma, Y. ); Chen, C.T.; Meigs, G.; Sette, F. ); Illing, G. ); Shigakawa, H. )

    1992-03-15

    High-resolution core-level photoemission spectra of the K/Si(111)(7{times}7) surface system are presented. The Si 2{ital p} results show that potassium adsorption induces a Si 2{ital p} core level to shift to o/Ihighero/P binding energy, i.e., to the opposite direction than that expected from the Si-K electronegativity differences. This result is compared with that of the K/Si(111)({radical}3 {times} {radical}3 ){ital R}30{degree}-B system and is interpreted in terms of the K-induced charge redistribution between the Si-adatom--rest-atom pair.

  5. Iterative algorithm for reconstructing rotationally asymmetric surface deviation with pixel-level spatial resolution

    NASA Astrophysics Data System (ADS)

    Quan, Haiyang; Wu, Fan; Hou, Xi

    2015-10-01

    New method for reconstructing rotationally asymmetric surface deviation with pixel-level spatial resolution is proposed. It is based on basic iterative scheme and accelerates the Gauss-Seidel method by introducing an acceleration parameter. This modified Successive Over-relaxation (SOR) is effective for solving the rotationally asymmetric components with pixel-level spatial resolution, without the usage of a fitting procedure. Compared to the Jacobi and Gauss-Seidel method, the modified SOR method with an optimal relaxation factor converges much faster and saves more computational costs and memory space without reducing accuracy. It has been proved by real experimental results.

  6. Statistical relation between monthly mean precipitable water and surface-level humidity over global oceans

    NASA Technical Reports Server (NTRS)

    Liu, W. T.

    1986-01-01

    Monthly summaries of atmospheric soundings taken over 17 years from 49 midocean stations at small islands and weather ships distributed over major oceans are examined. Over tropical oceans, precipitable water is found to be a better predictor of surface-level humidity than surface-level air temperature. A statistical relation in the form of a polynomial is derived; from this relation, the monthly-mean, surface-level mixing ratio can be computed from monthly-mean precipitable water. The root-mean-square differences between the measured and derived values were found to be less than 8 x 10 to the -4th over most ocean areas. Such a relation is useful in deriving large-scale evaporation and latent heat flux data from the ocean, using spaceborne observations. The temporal and spatial variabilities of data deviations from this relation are examined. This relation is found to be applicable to all major ocean basins and can be used to monitor interannual variability. Boundary-layer thermodynamics of different air masses are suggested as an explanation of some characteristics of this relation.

  7. Surface tension prediction for hydrocarbons and its application to level swell modelling.

    PubMed

    Cumber, Peter

    2002-01-28

    In this article, methods for estimating surface tension are considered where the specific gravity and normal boiling point are known such as when the composition is expressed using petroleum fractions. This is of interest as surface tension is an important parameter in the calculation of outflow conditions from a two-phase vessel undergoing level swell. A new improved correlation for the parachor is presented and the improved accuracy of the surface tension and bubble rise velocity compared to when the original parachor correlation is used is assessed. Finally the sensitivity of outflow predictions to changes in the surface tension is presented for a depressurising vessel containing pentane. For the vessel depressurisation simulation where the original parachor correlation is used, two-phase venting is maintained for two-three times as long compared to when the actual parachor or improved parachor correlation is used to estimate the surface tension. This has an impact on the error in predicting the mass flow rate as a source condition for other consequence models and also in vent sizing calculations. PMID:11744200

  8. Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

    NASA Astrophysics Data System (ADS)

    Puthirath, Anand B.; Methattel Raman, Shijeesh; Varma, Sreekanth J.; Jayalekshmi, S.

    2016-04-01

    Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

  9. Comparison of surface vacuum ultraviolet emissions with resonance level number densities. I. Argon plasmas

    SciTech Connect

    Boffard, John B. Lin, Chun C.; Culver, Cody; Wang, Shicong; Wendt, Amy E.; Radovanov, Svetlana; Persing, Harold

    2014-03-15

    Vacuum ultraviolet (VUV) photons emitted from excited atomic states are ubiquitous in material processing plasmas. The highly energetic photons can induce surface damage by driving surface reactions, disordering surface regions, and affecting bonds in the bulk material. In argon plasmas, the VUV emissions are due to the decay of the 1s{sub 4} and 1s{sub 2} principal resonance levels with emission wavelengths of 104.8 and 106.7 nm, respectively. The authors have measured the number densities of atoms in the two resonance levels using both white light optical absorption spectroscopy and radiation-trapping induced changes in the 3p{sup 5}4p→3p{sup 5}4s branching fractions measured via visible/near-infrared optical emission spectroscopy in an argon inductively coupled plasma as a function of both pressure and power. An emission model that takes into account radiation trapping was used to calculate the VUV emission rate. The model results were compared to experimental measurements made with a National Institute of Standards and Technology-calibrated VUV photodiode. The photodiode and model results are in generally good accord and reveal a strong dependence on the neutral gas temperature.

  10. Influence of reconstruction water-bearing levels on surface displacement of post-mining areas

    NASA Astrophysics Data System (ADS)

    Milczarek, Wojciech; Blachowski, Jan; Grzempowski, Piotr

    2014-05-01

    The phenomenon of secondary deformation characteristic of the post-mining areas is not sufficiently recognized. For ground surfaces phenomenon may be continuous or discontinuous. There is no sufficient information that describes behavior of the rock mass in the long term after end of exploitation. It is considered that this phenomenon is gradually disappears with end of exploitation. Reliable quantitative data comes only from the analysis of direct measurements in selected areas: geodetic and satellites measurements. Analyzing current situation of operating mines can be said that in the near years, more centers will limit the mining of coal mining. This will contribute to separation further of post-mining areas, in which will be required to maintaining a permanent monitoring and making predictions on the impact of ended exploitation of the rock mass surface. This will be particularly important for highly urbanized areas. This study used finite element method (FEM) to describe phenomenon of reconstruction water-bearing levels and its impact on displacement on the ground surface. It was assumed that significant factors that influence the occurrence and size of secondary deformations are: reconstruction of water-bearing levels in the prior drainer rock mass, size of past exploitation, spatial distribution of coal seams and geological and tectonic structure has been assumed. The transversally isotropic model of six elastic constants: E1 = E2, E3, ν = ν12, ν13, G12, G13 has been assumed to describe of rock mass in the numerical calculations. Geometrical models used in the numerical calculations have been developed using GIS tools. For the study two-dimensional and three-dimensional models characterized by different geological conditions and different configuration of mining data have been developed. The results obtained displacements of the ground surface for the period of mining activity has been verified with the results based on the Knothe theory. The results of

  11. Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

    SciTech Connect

    Simonds, Brian J.; Kheraj, Vipul; Palekis, Vasilios; Ferekides, Christos; Scarpulla, Michael A.

    2015-06-14

    Laser processing of polycrystalline CdTe is a promising approach that could potentially increase module manufacturing throughput while reducing capital expenditure costs. For these benefits to be realized, the basic effects of laser irradiation on CdTe must be ascertained. In this study, we utilize surface photovoltage spectroscopy (SPS) to investigate the changes to the electronic properties of the surface of polycrystalline CdTe solar cell stacks induced by continuous-wave laser annealing. The experimental data explained within a model consisting of two space charge regions, one at the CdTe/air interface and one at the CdTe/CdS junction, are used to interpret our SPS results. The frequency dependence and phase spectra of the SPS signal are also discussed. To support the SPS findings, low-temperature spectrally-resolved photoluminescence and time-resolved photoluminescence were also measured. The data show that a modest laser treatment of 250 W/cm{sup 2} with a dwell time of 20 s is sufficient to reduce the effects of Fermi level pinning at the surface due to surface defects.

  12. Roles of low-level thermodynamics on surface-convection interactions over West-Africa

    NASA Astrophysics Data System (ADS)

    Guichard, F.; Couvreux, F.; Gounou, A.; Nuret, M.

    2009-09-01

    This study aims to characterize the thermodynamics of the atmospheric low levels across West Africa (WA), on the basis of observations provided by the AMMA project. A dataset made of several thousands of high-resolution soundings is used for this purpose. Moist-convection related indexes, boundary layer (BL) parameters, and a combination of two indexes proposed by Findell and Eltahir (2003) (FE03) are compted for each sounding. These latter indexes are well suited for distinguishing between aspects of surface-atmosphere interactions involving atmospheric vertical structures. The variability of the low levels is found to be stronger in the Sahelian zone than in the Soudanian zone, from daily scale up to the monsoon season (JJAS). FE03 indexes suggest that surface-atmosphere feedbacks are actually significantly operating over West-Africa, but that the feedback loops change sign with latitude and season. Thus, thermodynamic environment at low level is broadly consistent with the idea of daytime convection being either suppressed or favoured over wet surface versus dry ones, depending on latitude and seasonal variations. This finding is consistent with observations that daytime convection is not always favoured over wet land surfaces. It remains to assess the scale down to which the local thermodynamic environment is actually playing a role, and how it combines with other factors, such as turbulence, clouds and mesoscale circulations, to explain observations. Variations of the lifting condensation level (LCL) and level of free convection (LFC) are further consistent with the previous analysis. For instance, in Niamey (Sahelian), a strong diurnal cycle of LCL is found, especially early in the season, while the LFC does not fluctuates much with the hour in the day, but shifts downwards from June to August. The LCL is however not such a good indicator of BL height when the low levels are the driest. This is particularly true in June in the Sahel, on days when none of the

  13. Potential relation between equatorial sea surface temperatures and historic water level variability for Lake Turkana, Kenya

    NASA Astrophysics Data System (ADS)

    Bloszies, Chris; Forman, Steven L.

    2015-01-01

    Water level in Lake Turkana, Kenya in the past ca. 150 years is controlled primarily from the biannual passage of the East and West African Monsoon, with rainfall volume related partially to sea surface temperatures (SSTs) in the Western Indian and East Atlantic oceans. Empirical orthogonal function analyses show significant correlation between Eastern Atlantic or Western Indian SSTs and lake level anomalies, with the first mode accounting for 66% and 55% of the variability. The primary geographic loadings are consistent with a Gulf of Guinea moisture source and positive Indian Ocean Dipole (IOD) state. The second mode explains 10% of variability, and reflects the westward extension of an Indian Ocean cool pool, potentially indicative of a normal to a negative IOD state. There is significant spatial correlation between basin rainfall anomalies associated with Eastern Atlantic SSTs and a low in the continental divide between the Kenyan and the Ethiopian Highlands, which is a passage for moisture from the Congo Basin. Linear regression analysis with Bootstrap sampling and Monte Carlo simulations define numeric relations between Western Indian and Eastern Atlantic SSTs and lake level change for AD 1992-2013. The monthly and yearly lake level reconstructions based on this numeric analysis capture the decadal-scale variability and the 15 m drop in water level in the early 20th century. Meter-scale variability in lake level since ca. AD 1930 is associated with precipitation sourced from the Western Indian Ocean with IOD variability, whereas the 15 m drop in water level in the early 20th century may reflect a profound decrease in moisture from Atlantic/Congo Basin source. These numerical solutions are poised to reconstruct water level variations in the past ca. 300 years for Lake Turkana with new proxy records of SSTs from the Western Indian Ocean and the Gulf of Guinea.

  14. Modelling the impact of global changes on European summer surface ozone levels at the 2050 horizon

    NASA Astrophysics Data System (ADS)

    Clain, Gaelle; Szopa, Sophie; Vautard, Robert; Bessagnet, Bertrand; Colette, Augustin

    2013-04-01

    As pointed by the IPCC, climate change and evolution of green house gases emissions in the coming decades are likely to affect regional pollution levels as well as the background ozone levels (Jacob et al., 1999): first, the evolution of climate due to the increase of green house gas emissions is liable to induce modifications of the meteorological parameters of crucial interest for air quality. Secondly, the emissions of air pollutants will be affected by changes in population and energy demands as well as policy aiming to reduce global warming or pollution impacts. In order to assess the relative impact of climate change and change in green house gas emissions, a set of regional simulations is conducted using CHIMERE model (Bessagnet et al., 2009). These simulations account for change in anthropogenic emissions of precursors from future scenarii, global background pollutant levels through appropriate boundary conditions from LMDz-INCA model, and future meteorological conditions reflecting AR5 scenario. For consistency, all these forcings are built on the same scenario: the RCP 8.5 (Representative Concentration Pathways, Riahi et al., 2007) developed in IPCC-AR5 framework for climate projections. The RCP8.5 scenario used in this study is defined by a rising radiative forcing pathway leading to 8.5 W.m-2 in 2100. Long term simulations of summer periods (July 1st to August 31st ) with CHIMERE model are conducted, reproducing present (1995-2005), future (2045-2055) conditions in emissions, climate, and boundary conditions. Mean summer surface ozone levels from each simulated case are compared in order to discriminate the impact of climate and the impact of RCP8.5 scenario emission progression alone on surface ozone levels.

  15. Observation of Landau levels on nitrogen-doped flat graphite surfaces without external magnetic fields

    NASA Astrophysics Data System (ADS)

    Kondo, Takahiro; Guo, Donghui; Shikano, Taishi; Suzuki, Tetsuya; Sakurai, Masataka; Okada, Susumu; Nakamura, Junji

    2015-11-01

    Under perpendicular external magnetic fields, two-dimensional carriers exhibit Landau levels (LLs). However, it has recently been reported that LLs have been observed on graphene and graphite surfaces without external magnetic fields being applied. These anomalous LLs have been ascribed primarily to a strain of graphene sheets, leading to in-plane hopping modulation of electrons. Here, we report the observation of the LLs of massive Dirac fermions on atomically flat areas of a nitrogen-doped graphite surface in the absence of external magnetic fields. The corresponding magnetic fields were estimated to be as much as approximately 100 T. The generation of the LLs at the area with negligible strain can be explained by inequivalent hopping of π electrons that takes place at the perimeter of high-potential domains surrounded by positively charged substituted graphitic-nitrogen atoms.

  16. Interaction between low-level jet and sea surface temperature gradient in the Carolina Capes

    SciTech Connect

    Xie, L.; Pietrafesa, L.J.; Raman, S.

    1994-12-31

    The continental shelf off the Carolina coast is a preferred region of formation of low-level jet, coastal fronts and cyclones. During winter, the sharp contrast between the warm and moist air over the coastal waters and the cold and dry air over the continent forms an intense baroclinic zone along the coast. This baroclinic zone is often enhanced by a cold-air damming to the east of the Appalachian mountains. On the other hand, coastal waters, particularly the inner- and mid-shelf waters in the Carolina Capes are strongly affected by winds and surface cooling. According to these studies, the most energetic subtidal variance of midshelf circulation occurs between 2 and 10 days which coincide with the energy peaks of local surface winds. A fundamental question is whether or not mesoscale atmospheric systems are effectively coupled to the ocean circulation and frontal features over the shelf. This question will be the focus of this study.

  17. Physics of the Be(10{bar 1} 0) Surface Core Level Spectrum

    SciTech Connect

    Lizzit, S.; Pohl, K. |; Baraldi, A.; Comelli, G.; Fritzsche, V.; Plummer, E.W. |; Stumpf, R.; Hofmann, P. ||

    1998-10-01

    Photoelectron diffraction has been utilized to confirm the theoretical prediction that the surface core level shifts observed for Be(10{bar 1}0) have been improperly assigned. The original assignment based upon the relative intensity of the shifted components was intuitively obvious: the peak with the largest shift of {minus}0.7 eV with respect to the bulk was associated with the surface plane, the next peak shifted by {minus}0.5 eV stems from the second layer, and the third peak at {minus}0.22 eV from the third and fourth layers. First-principles theory and our experimental data show that the largest shift is associated with the second plane, not the first plane. {copyright} {ital 1998} {ital The American Physical Society }

  18. Observation of Landau levels on nitrogen-doped flat graphite surfaces without external magnetic fields

    PubMed Central

    Kondo, Takahiro; Guo, Donghui; Shikano, Taishi; Suzuki, Tetsuya; Sakurai, Masataka; Okada, Susumu; Nakamura, Junji

    2015-01-01

    Under perpendicular external magnetic fields, two-dimensional carriers exhibit Landau levels (LLs). However, it has recently been reported that LLs have been observed on graphene and graphite surfaces without external magnetic fields being applied. These anomalous LLs have been ascribed primarily to a strain of graphene sheets, leading to in-plane hopping modulation of electrons. Here, we report the observation of the LLs of massive Dirac fermions on atomically flat areas of a nitrogen-doped graphite surface in the absence of external magnetic fields. The corresponding magnetic fields were estimated to be as much as approximately 100 T. The generation of the LLs at the area with negligible strain can be explained by inequivalent hopping of π electrons that takes place at the perimeter of high-potential domains surrounded by positively charged substituted graphitic-nitrogen atoms. PMID:26549618

  19. Surface hole accumulation and Fermi level stabilization energy in SnTe

    NASA Astrophysics Data System (ADS)

    Nishitani, Junichi; Detert, Douglas; Beeman, Jeffrey; Yu, Kin Man; Walukiewicz, Wladek

    2014-09-01

    SnTe films were deposited by RF magnetron sputtering. The thickness dependence of the sheet hole concentration indicated the presence of a high hole density surface accumulation layer. Irradiation of SnTe by Ne+ ions led to the saturation of the hole concentration corresponding to a Fermi energy that is 0.5 eV below the valence band edge. The stabilized Fermi energy on the surface and in the heavily damaged bulk is in agreement with the amphoteric native defect model. These results show that SnTe is a unique semiconductor with an extremely high valence band edge located at 4.4 eV below the vacuum level.

  20. Automatic leveling procedure by use of the spring method in measurement of three-dimensional surface roughness

    NASA Astrophysics Data System (ADS)

    Kurokawa, Syuhei; Ariura, Yasutsune; Yamamoto, Tatsuyuki

    2008-12-01

    Leveling of specimen surfaces is very important in measurement of surface roughness. If the surface is not leveled, the measured roughness has large distortion and less vertical measurement range. It is convenient to utilize some automatic leveling procedures instead of manual leveling which needs longer adjustment time. In automatic leveling, a new algorithm is proposed, which is named the spring method superior to the least square method. The spring method has an advantage that a part of tentative data points is used to calculate the surface inclination, so the obtained results are less influenced by local pits for example. As examples, the spring method was applied to actual engineered surfaces, which were milled, shot-peened, and ground surfaces, and also an artificial ditched surface. The results went well for the calculation of the surface inclinations and consequently the specimen surfaces were leveled with less distortion and large vertical measurement range can be achieved. It is also found the least square method is a special case of the spring method with using all sampling data points. That means the spring method is a comprehensive procedure including the least square method. This must become a very strong and robust method in automatic leveling algorithm

  1. Preferences of lame cows for type of surface and level of social contact in hospital pens.

    PubMed

    Jensen, M B; Herskin, M S; Thomsen, P T; Forkman, B; Houe, H

    2015-07-01

    To investigate preferences of lame cows for flooring and level of social contact, 37 lame, lactating dairy cows (diagnosed with sole ulcer or white line disease) were housed individually for 6 d in experimental hospital pens, where they could choose between 2 equally sized areas (6m × 4.5m) with either deep-bedded sand or a rubber surface. On both surfaces, cows could choose between 2 equally sized areas either near or away from heifers in a neighboring group pen. Cows spent more time lying on the deep-bedded sand than on the rubber surface (870 vs. 71min/d), whereas they spent less time upright (standing or walking) on the sand than on the rubber surface (180 vs. 319min/d). In addition, cows spent less time self-grooming on the sand than on the rubber surface (2.2 vs. 4.7% of time spent upright). With regard to level of social contact, cows spent more time near the neighboring heifers than away from them; this was true both while lying (565 vs. 374min/d) and upright (276 vs. 223min/d). Self-grooming was seen significantly more near neighboring heifers than away from them (4.8 vs. 3.3% of time spent upright). When lying, cows more often positioned themselves in areas of the pen where they could maintain visual contact with neighboring heifers. Lame cows with sole ulcers or white line disease preferred deep-bedded sand for lying, and preferred to perform self-grooming while on the rubber surface. Similarly, they preferred to lie and to perform self-grooming while positioned near animals in a neighboring pen. These results suggest that provision of a deep-bedded lying area in hospital pens is important to the welfare of lame cows. We found no evidence of isolation-seeking behavior in animals with these diagnoses (and no systemic symptoms) while they were kept in individual hospital pens. PMID:25935249

  2. Levels of hydrocarbons in mussels, Mytilus edulis, and surface sediments from Danish coastal areas

    SciTech Connect

    Jensen, K.

    1981-02-01

    Until recently, most effort in oil pollution research has been spent on investigating the effects of oil spills and use of detergents. The effects of long-term low level input to the marine environment are much less elucidated. This study represents the first step in a project concerning chronic oil pollution undertaken by the Marine Pollution Laboratory, Denmark. Results from previous studies on this subject in the area concerned, which have not been internationally published, are also included. In a series of Danish coastal localities, samples of surface sediments (top cm) were taken and samples of blue mussels, Mytilus edulis, were collected by SCUBA diving.

  3. Experimental observation of surface states and Landau levels bending in bilayer graphene

    NASA Astrophysics Data System (ADS)

    Yin, Long-Jing; Zhang, Yu; Qiao, Jia-Bin; Li, Si-Yu; He, Lin

    2016-03-01

    We report on microscopic measurements of the low-energy electronic structures both at the zigzag and armchair edges of bilayer graphene using scanning tunneling microscopy and spectroscopy (STM and STS). We have found that, both in the absence and in the presence of a magnetic field, an almost zero-energy peak in the density of states was localized at the zigzag edges, as expected for the surface states at the zigzag edges of bilayer graphene. In the quantum Hall regime, we have clearly observed Landau levels bending away from the charge neutrality point near both the zigzag and armchair edges. Such a result is direct evidence for the evolution of Landau levels into quantum Hall edge states in graphene bilayers. Our experiment indicates that it is possible to explore rich quantum Hall physics in graphene systems using STM and STS.

  4. Paper-based surfaced enhanced Raman spectroscopy for drug level testing with tear fluid

    NASA Astrophysics Data System (ADS)

    Yamada, Kenji; Yokoyama, Moe; Jeong, Hieyong; Kido, Michiko; Ohno, Yuko

    2015-07-01

    The purpose of this study was to show the effectiveness of therapeutic drug level testing by Paper-based Surfaced Enhanced Raman Spectroscopy (PSERS) for artificial lacrimal fluid. We have been used substrates which consist of a common filter paper and gold nano-rods. The targets were Phenobarbital (PB) which dissolved in artificial lacrimal fluid. We measured them using PSERS which the wavelength was 785nm, the power was 30mW. It was found that there were the strong peaks of PB at 997cm-1 and 1026cm-1 which corresponded with solid PB spectral peak for 1mM artificial lacrimal fluid. The results demonstrated the usefulness of this method. It is concluded that our method for therapeutic drug level testing is very efficient.

  5. Active Monte Carlo Localization in Outdoor Terrains Using Multi-level Surface Maps

    NASA Astrophysics Data System (ADS)

    Kümmerle, Rainer; Pfaff, Patrick; Triebel, Rudolph; Burgard, Wolfram

    In this paper we consider the problem of active mobile robot localization with range sensors in outdoor environments. In contrast to passive approaches our approach actively selects the orientation of the laser range finder to improve the localization results. It applies a particle filter to estimate the full sixdimensional state of the robot. To represent the environment we utilize multi-level surface maps which allow the robot to represent vertical structures and multiple levels. To efficiently calculate the optimal orientation for the range scanner, we apply a clustering operation on the particles and only evaluate potential orientations based on these clusters. Experimental results obtained with a mobile robot in an outdoor environment indicate that the active control of the range sensor leads to more efficient localization results.

  6. Surface ozone levels in the forest and vegetation areas of the Biga Peninsula, Turkey.

    PubMed

    Sari, Deniz; İncecik, Selahattin; Ozkurt, Nesimi

    2016-11-15

    Spatial and temporal variability of surface ozone in the rural, mountainous and suburban sites of Biga Peninsula, at the northwest of Turkey which is about 300km southwest of Istanbul was investigated using passive samplers and continuous analyzers. A total 10 passive samplers and two continuous analyzers were used between 1.1.2013 and 31.12.2014. OX levels in the study region were examined to understand NOx dependent or independent contribution to ozone. The influences of the meteorological parameters on ozone levels were also examined by wind speed and ambient temperature. The results clearly show that mountainous areas have higher cumulative exposure to ozone than suburban locations. In order to understand the long range transport sources contributing to the high ozone levels in the region backward trajectories were computed using HYSPLIT model and then clustering of trajectories are performed. The results clearly show the characteristics of pollutant transport from north to Biga Peninsula. Additionally, AOT40 (Accumulated hourly O3 concentrations Over a Threshold of 40ppb) cumulative index was calculated using daytime hourly measurements. The results indicate that the ozone values in the study area are much higher than the critical levels for forest and vegetation based on EU Directive 2008/50/EC. PMID:27474990

  7. Measurements of Location-Dependent Nitric Oxide Levels on Skin Surface in relation to Acupuncture Point

    PubMed Central

    Ha, Yejin; Kim, Misun; Nah, Jiseon; Suh, Minah; Lee, Youngmi

    2012-01-01

    Location-dependent skin surface's partial nitric oxide pressure (pNO) is studied using highly sensitive amperometric NO microsensor with a small sensing area (diameter  = 76 μm). The pNO level of LI4 (Hegu) acupuncture point is measured and compared with the pNO level of nonacupuncture point. In addition, the mapping of pNO is carried out over the left wrist skin area one- as well as two-dimensionally. Statistically higher pNO levels near the position of acupuncture points than non-acupuncture points are observed consistently, implying tight relationship between the level of NO release of skin and acupuncture points. The amperometric planar NO microsensor successfully monitors the heterogeneity of skin pNO distribution in high spatial resolution due to its advantageous features such as high sensitivity and small sensing dimension. The current study suggests the direct connection between NO and acupuncture points and possibly provides beneficial information to understand physiological roles and basis of the acupuncture points. PMID:23049611

  8. High-Level Clouds and Relation to Sea Surface Temperature as Inferred from Japan's GMS Measurements

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah; Lindzen, Richard S.; Lee, Kyu-Tae; Einaudi, Franco (Technical Monitor)

    2000-01-01

    High-level clouds have a significant impact on the radiation energy budgets and, hence, the climate of the Earth. Convective cloud systems, which are controlled by large-scale thermal and dynamical conditions, propagate rapidly within days. At this time scale, changes of sea surface temperature (SST) are small. Radiances measured by Japan's Geostationary Meteorological Satellite (GMS) are used to study the relation between high-level clouds and SST in the tropical western and central Pacific (30 S-30 N; 130 E-170 W), where the ocean is warm and deep convection is intensive. Twenty months (January 1998 - August, 1999) of GMS data are used, which cover the second half of the strong 1997-1998 El Nino. Brightness temperature at the 11-micron channel is used to identify high-level clouds. The core of convection is identified based on the difference in the brightness temperatures of the 11- and 12-micron channels. Because of the rapid movement of clouds, there is little correlation between clouds six hours apart. When most of deep convection moves to regions of high SST, the domain averaged high-level cloud amount decreases. A +2C change of SST in cloudy regions results in a relative change of -30% in high-level cloud amount. This large change in cloud amount is due to clouds moving from cool regions to warm regions but not the change in SST itself. A reduction in high-level cloud amount in the equatorial region implies an expanded dry upper troposphere in the off-equatorial region, and the greenhouse warming of high clouds and water vapor is reduced through enhanced longwave cooling to space. The results are important for understanding the physical processes relating SST, convection, and water vapor in the tropics. They are also important for validating climate simulations using global general circulation models.

  9. Interplay between Self-Assembled Structures and Energy Level Alignment of Benzenediamine on Au(111) Surfaces

    NASA Astrophysics Data System (ADS)

    Li, Guo; Neaton, Jeffrey

    2015-03-01

    Using van der Waals-corrected density functional theory (DFT) calculations, we study the adsorption of benzene-diamine (BDA) molecules on Au(111) surfaces. We find that at low surface coverage, the adsorbed molecules prefer to stay isolated from each other in a monomer phase, due to the inter-molecular dipole-dipole repulsions. However, when the coverage rises above a critical value of 0.9nm-2, the adsorbed molecules aggregate into linear structures via hydrogen bonding between amine groups, consistent with recent experiments [Haxton, Zhou, Tamblyn, et al, Phys. Rev. Lett. 111, 265701 (2013)]. Moreover, we find that these linear structures at high density considerably reduces the Au work function (relative to a monomer phase). Due to reduced surface polarization effects, we estimate that the resonance energy of the highest occupied molecular orbital of the adsorbed BDA molecule relative to the Au Fermi level is significantly lower than the monomer phase by more than 0.5 eV, consistent with the experimental measurements [DellAngela, Kladnik, and Cossaro, et al., Nano Lett. 10, 2470 (2010)]. This work supported by DOE (the JCAP under Award Number DE-SC000499 and the Molecular Foundry of LBNL), and computational resources provided by NERSC.

  10. Comparison pesticide residue levels in the surface of Bertam River in Cameron Highlands, Pahang

    NASA Astrophysics Data System (ADS)

    Haron, S. H.; Ismail B., S.

    2015-09-01

    The presence of pesticide residues in the surface water of Bertam River in the agricultural areas of Cameron Highlands in Pahang, Malaysia was monitored from May to October 2014. The sampling sites were located at 10 sampling points along the Bertam River in the vegetable planting areas. The extraction method of the pesticide (organophosphate/pyrethroid) from the river samples used solid phase extraction followed by gas chromatography (with electron capture detector, ECD). Insecticides, cypermethrin and chlorpyrifos were found in the surface water of Bertam River. High level concentrations of those insecticides in the river were observed during the period from May to October 2014, a period which included both seasons (wet and dry seasons). The highest concentration of 2.66 µg/mL and 1.23 µg/mL of cypermethrin was observed during the wet and dry seasons respectively. This could be due to the frequent usage of the above-mentioned insecticides coupled with contamination that could have originated from the application sites. Meanwhile, the lowest concentration detected in the surface water was chlorpyrifos (0.11 µg/mL and 0.17 µg/mL) during the dry and wet seasons, respectively.

  11. Comparison pesticide residue levels in the surface of Bertam River in Cameron Highlands, Pahang

    SciTech Connect

    Haron, S. H. Ismail, B. S.

    2015-09-25

    The presence of pesticide residues in the surface water of Bertam River in the agricultural areas of Cameron Highlands in Pahang, Malaysia was monitored from May to October 2014. The sampling sites were located at 10 sampling points along the Bertam River in the vegetable planting areas. The extraction method of the pesticide (organophosphate/pyrethroid) from the river samples used solid phase extraction followed by gas chromatography (with electron capture detector, ECD). Insecticides, cypermethrin and chlorpyrifos were found in the surface water of Bertam River. High level concentrations of those insecticides in the river were observed during the period from May to October 2014, a period which included both seasons (wet and dry seasons). The highest concentration of 2.66 µg/mL and 1.23 µg/mL of cypermethrin was observed during the wet and dry seasons respectively. This could be due to the frequent usage of the above-mentioned insecticides coupled with contamination that could have originated from the application sites. Meanwhile, the lowest concentration detected in the surface water was chlorpyrifos (0.11 µg/mL and 0.17 µg/mL) during the dry and wet seasons, respectively.

  12. MARCH1 regulates insulin sensitivity by controlling cell surface insulin receptor levels.

    PubMed

    Nagarajan, Arvindhan; Petersen, Max C; Nasiri, Ali R; Butrico, Gina; Fung, Annie; Ruan, Hai-Bin; Kursawe, Romy; Caprio, Sonia; Thibodeau, Jacques; Bourgeois-Daigneault, Marie-Claude; Sun, Lisha; Gao, Guangping; Bhanot, Sanjay; Jurczak, Michael J; Green, Michael R; Shulman, Gerald I; Wajapeyee, Narendra

    2016-01-01

    Insulin resistance is a key driver of type 2 diabetes (T2D) and is characterized by defective insulin receptor (INSR) signalling. Although surface INSR downregulation is a well-established contributor to insulin resistance, the underlying molecular mechanisms remain obscure. Here we show that the E3 ubiquitin ligase MARCH1 impairs cellular insulin action by degrading cell surface INSR. Using a large-scale RNA interference screen, we identify MARCH1 as a negative regulator of INSR signalling. March1 loss-of-function enhances, and March1 overexpression impairs, hepatic insulin sensitivity in mice. MARCH1 ubiquitinates INSR to decrease cell surface INSR levels, but unlike other INSR ubiquitin ligases, MARCH1 acts in the basal state rather than after insulin stimulation. Thus, MARCH1 may help set the basal gain of insulin signalling. MARCH1 expression is increased in white adipose tissue of obese humans, suggesting that MARCH1 contributes to the pathophysiology of T2D and could be a new therapeutic target. PMID:27577745

  13. Half-filled Landau level, topological insulator surfaces, and three-dimensional quantum spin liquids

    NASA Astrophysics Data System (ADS)

    Wang, Chong; Senthil, T.

    2016-02-01

    We synthesize and partly review recent developments relating the physics of the half-filled Landau level in two dimensions to correlated surface states of topological insulators in three dimensions. The latter are in turn related to the physics of certain three-dimensional quantum spin liquid states. The resulting insights provide an interesting answer to the old question of how particle-hole symmetry is realized in composite fermion liquids. Specifically the metallic state at filling ν =1/2 —described originally in pioneering work by Halperin, Lee, and Read as a liquid of composite fermions—was proposed recently by Son to be described by a particle-hole symmetric effective field theory distinct from that in the prior literature. We show how the relation to topological insulator surface states leads to a physical understanding of the correctness of this proposal. We develop a simple picture of the particle-hole symmetric composite fermion through a modification of older pictures as electrically neutral "dipolar" particles. We revisit the phenomenology of composite fermi liquids (with or without particle-hole symmetry), and show that their heat/electrical transport dramatically violates the conventional Wiedemann-Franz law but satisfies a modified one. We also discuss the implications of these insights for finding physical realizations of correlated topological insulator surfaces.

  14. Origin of Fermi-level pinning and its control on the n -type Ge(100) surface

    NASA Astrophysics Data System (ADS)

    Kuzmin, Mikhail; Laukkanen, Pekka; Mäkelä, Jaakko; Tuominen, Marjukka; Yasir, Muhammad; Dahl, Johnny; Punkkinen, Marko P. J.; Kokko, Kalevi

    2016-07-01

    Strong Fermi-level pinning (FLP) near the valence-band maximum on n -type Ge surfaces has been a long-standing challenge in semiconductor physics, and the nature of this phenomenon has been heavily debated for years. Here, we report a systematic synchrotron-based photoemission study of atomically well-defined Ge(100) surfaces and interfaces to elucidate the origin of FLP in such systems. It is experimentally shown that the FLP on n -Ge is not due to the dangling-bond, back-bond, and defect states, but is strongly contributed by the evanescent state of the Ge bulk. The conditions required for alleviating the FLP and even the implementation of a flatband structure on Ge(100) are formulated. Such a structure is realized in the BaO/Ge(100) system where one can obtain control over the Fermi-level position in the Ge gap. These findings are not only important from a fundamental viewpoint, but also open a route to producing Ohmic metal-insulator-semiconductor contacts for n -type Ge-based technology.

  15. The SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) Product

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf; Crow, Wade; Koster, Randal; Kimball, John

    2010-01-01

    The Soil Moisture Active and Passive (SMAP) mission is being developed by NASA for launch in 2013 as one of four first-tier missions recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space in 2007. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, the high resolution soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. In this paper we describe the assimilation of SMAP observations for the generation of the planned SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) product. The SMAP mission makes simultaneous active (radar) and passive (radiometer) measurements in the 1.26-1.43 GHz range (L-band) from a sun-synchronous low-earth orbit. Measurements will be obtained across a 1000 km wide swath using conical scanning at a constant incidence angle (40 deg). The radar resolution varies from 1-3 km over the outer 70% of the swath to about 30 km near the center of the swath. The radiometer resolution is 40 km across the entire swath. The radiometer measurements will allow high-accuracy but coarse resolution (40 km) measurements. The radar measurements will add significantly higher resolution information. The radar is however very sensitive to surface roughness and vegetation structure. The combination of the two measurements allows optimal blending of the advantages of each instrument. SMAP directly observes only surface soil moisture (in the top 5 cm of the soil column). Several of the key applications targeted by SMAP, however, require knowledge of root zone soil moisture (approximately top 1 m of the soil column), which is not directly measured by SMAP. The foremost objective of the SMAP L4_SM product is to fill this gap and provide estimates of root zone soil moisture

  16. Surface capping and size-dependent toxicity of gold nanoparticles on different trophic levels.

    PubMed

    Iswarya, V; Manivannan, J; De, Arpita; Paul, Subhabrata; Roy, Rajdeep; Johnson, J B; Kundu, Rita; Chandrasekaran, N; Mukherjee, Anita; Mukherjee, Amitava

    2016-03-01

    In the present study, the toxicity of gold nanoparticles (Au NPs) was evaluated on various trophic organisms. Bacteria, algae, cell line, and mice were used as models representing different trophic levels. Two different sizes (CIT30 and CIT40) and surface-capped (CIT30-polyvinyl pyrrolidone (PVP)-capped) Au NPs were selected. CIT30 Au NP aggregated more rapidly than CIT40 Au NP, while an additional capping of PVP (CIT30-PVP capped Au NP) was found to enhance its stability in sterile lake water medium. Interestingly, all the forms of NPs evaluated were stable in the cell culture medium during the exposure period. Size- and dose-dependent cytotoxicities were observed in both bacteria and algae, with a strong dependence on reactive oxygen species (ROS) generation and lactate dehydrogenase (LDH) release. CIT30-PVP capped Au NP showed a significant decrease in toxicity compared to CIT30 Au NP in bacteria and algae. In the SiHa cell line, dose- and exposure-dependent decline in cell viability were noted for all three types of Au NPs. In mice, the induction of DNA damage was size and dose dependent, and surface functionalization with PVP reduced the toxic effects of CIT30 Au NP. The exposure to CIT30, CIT40, and CIT30-PVP capped Au NPs caused an alteration of the oxidative stress-related endpoints in mice hepatocytes. The toxic effects of the gold nanoparticles were found to vary in diverse test systems, accentuating the importance of size and surface functionalization at different trophic levels. PMID:26545887

  17. Space-based detection of wetlands' surface water level changes from L-band SAR interferometry

    USGS Publications Warehouse

    Wdowinski, S.; Kim, S.-W.; Amelung, F.; Dixon, T.H.; Miralles-Wilhelm, F.; Sonenshein, R.

    2008-01-01

    Interferometric processing of JERS-1 L-band Synthetic Aperture Radar (SAR) data acquired over south Florida during 1993-1996 reveals detectable surface changes in the Everglades wetlands. Although our study is limited to south Florida it has implication for other large-scale wetlands, because south Florida wetlands have diverse vegetation types and both managed and natural flow environments. Our analysis reveals that interferometric coherence level is sensitive to wetland vegetation type and to the interferogram time span. Interferograms with time spans less than six months maintain phase observations for all wetland types, allowing characterization of water level changes in different wetland environments. The most noticeable changes occur between the managed and the natural flow wetlands. In the managed wetlands, fringes are organized, follow patterns related to some of the managed water control structures and have high fringe-rate. In the natural flow areas, fringes are irregular and have a low fringe-rate. The high fringe rate in managed areas reflects dynamic water topography caused by high flow rate due to gate operation. Although this organized fringe pattern is not characteristic of most large-scale wetlands, the high level of water level change enables accurate estimation of the wetland InSAR technique, which lies in the range of 5-10??cm. The irregular and low rate fringe pattern in the natural flow area reflects uninterrupted flow that diffuses water efficiently and evenly. Most of the interferograms in the natural flow area show an elongated fringe located along the transitional zone between salt- and fresh-water wetlands, reflecting water level changes due to ocean tides. ?? 2007 Elsevier Inc. All rights reserved.

  18. Surface dental enamel lead levels and antisocial behavior in Brazilian adolescents.

    PubMed

    Olympio, Kelly P K; Oliveira, Pedro V; Naozuka, Juliana; Cardoso, Maria R A; Marques, Antonio F; Günther, Wanda M R; Bechara, Etelvino J H

    2010-01-01

    Lead poisoning has been reportedly linked to a high risk of learning disabilities, aggression and criminal offenses. To study the association between lead exposure and antisocial/delinquent behavior, a cross-sectional study was conducted with 173 Brazilian youths aged 14-18 and their parents (n=93), living in impoverished neighborhoods of Bauru-SP, with high criminality indices. Self-Reported Delinquency (SRD) and Child Behavior Checklist (CBCL) questionnaires were used to evaluate delinquent/antisocial behavior. Body lead burdens were evaluated in surface dental enamel acid microbiopsies. The dental enamel lead levels (DELL) were quantified by graphite furnace atomic absorption spectrometry (GFAAS) and phosphorus content was measured using inductively coupled plasma optical emission spectrometry (ICP-OES). Logistic regression was used to identify associations between DELL and each scale defined by CBCL and SRD scores. Odd ratios adjusted for familial and social covariates, considering a group of youths exposed to high lead levels (>or=75 percentile), indicated that high DELL is associated with increased risk of exceeding the clinical score for somatic complaints, social problems, rule-breaking behavior and externalizing problems (CI 95%). High DELL was not found to be associated with elevated SRD scores. In conclusion, our data support the hypothesis that high-level lead exposure can trigger antisocial behavior, which calls for public policies to prevent lead poisoning. PMID:20005947

  19. Using continuous surface water level and temperature data to characterize hydrological connectivity in riparian wetlands.

    PubMed

    Cabezas, Alvaro; Gonzalez-Sanchís, Maria; Gallardo, Belinda; Comín, Francisco A

    2011-12-01

    Methods to characterize hydrological connectivity at riparian wetlands are necessary for ecosystem management given its importance over ecosystem structure and functioning. In this paper, we aimed to describe hydrological connectivity at one Ebro River reach (NE Spain) and test a method to perform such characterization. Continuous surface water level and temperature data were recorded at five riparian wetlands during the period October 2006-June 2007. Combining water level and temperature, we classified the examined wetlands in three groups, which mainly differed in the dominant water source during different flood stages. Firstly, a comparison of water level fluctuations in riparian wetlands with those in the river channel during events with different characteristics was used to describe hydrological connectivity. Such comparison was also used to extract quantitative hydrological connectivity descriptors as the wetland response initiation time. Secondly, water temperature series were divided in phases with different average, range and daily oscillation, and these parameters were interpreted for each phase to identify dominant flowpaths. By doing so, a more complete description of hydrological connectivity was achieved. Our method provided useful insights to describe hydrological connectivity using a qualitative approach that can be expanded if required to include quantitative parameters for studies of biotic assemblages or ecosystem processes. PMID:21400244

  20. A Response Surface Methodology for Bi-Level Integrated System Synthesis (BLISS)

    NASA Technical Reports Server (NTRS)

    Altus, Troy David; Sobieski, Jaroslaw (Technical Monitor)

    2002-01-01

    The report describes a new method for optimization of engineering systems such as aerospace vehicles whose design must harmonize a number of subsystems and various physical phenomena, each represented by a separate computer code, e.g., aerodynamics, structures, propulsion, performance, etc. To represent the system internal couplings, the codes receive output from other codes as part of their inputs. The system analysis and optimization task is decomposed into subtasks that can be executed concurrently, each subtask conducted using local state and design variables and holding constant a set of the system-level design variables. The subtasks results are stored in form of the Response Surfaces (RS) fitted in the space of the system-level variables to be used as the subtask surrogates in a system-level optimization whose purpose is to optimize the system objective(s) and to reconcile the system internal couplings. By virtue of decomposition and execution concurrency, the method enables a broad workfront in organization of an engineering project involving a number of specialty groups that might be geographically dispersed, and it exploits the contemporary computing technology of massively concurrent and distributed processing. The report includes a demonstration test case of supersonic business jet design.

  1. Improving Limit Surface Search Algorithms in RAVEN Using Acceleration Schemes: Level II Milestone

    SciTech Connect

    Alfonsi, Andrea; Rabiti, Cristian; Mandelli, Diego; Cogliati, Joshua Joseph; Sen, Ramazan Sonat; Smith, Curtis Lee

    2015-07-01

    , subject of the analysis. These methodologies are named, in the RAVEN environment, adaptive sampling strategies. These methodologies infer system responses from surrogate models constructed from already existing samples (produced using high fidelity simulations) and suggest the most relevant location (coordinate in the input space) of the next sampling point to be explored in the uncertain/parametric domain. When using those methodologies, it is possible to understand features of the system response with a small number of carefully selected samples. This report focuses on the development and improvement of the limit surface search. The limit surface is an important concept in system reliability analysis. Without going into the details, which will be covered later in the report, the limit surface could be briefly described as an hyper-surface in the system uncertainty/parametric space separating the regions leading to a prescribed system outcome. For example, if the uncertainty/parametric space is the one generated by the reactor power level and the duration of the batteries, the system is a nuclear power plant and the system outcome discriminating variable is the clad failure in a station blackout scenario, then the limit surface separates the combinations of reactor power level and battery duration that lead to clad failure from the ones that do not.

  2. Facet personality and surface-level diversity as team mental model antecedents: implications for implicit coordination.

    PubMed

    Fisher, David M; Bell, Suzanne T; Dierdorff, Erich C; Belohlav, James A

    2012-07-01

    Team mental models (TMMs) have received much attention as important drivers of effective team processes and performance. Less is known about the factors that give rise to these shared cognitive structures. We examined potential antecedents of TMMs, with a specific focus on team composition variables, including various facets of personality and surface-level diversity. Further, we examined implicit coordination as an important outcome of TMMs. Results suggest that team composition in terms of the cooperation facet of agreeableness and racial diversity were significantly related to team-focused TMM similarity. TMM similarity was also positively predictive of implicit coordination, which mediated the relationship between TMM similarity and team performance. Post hoc analyses revealed a significant interaction between the trust facet of agreeableness and racial diversity in predicting TMM similarity. Results are discussed in terms of facilitating the emergence of TMMs and corresponding implications for team-related human resource practices. PMID:22468847

  3. Energy pumping analysis of skating motion in a half pipe and on a level surface

    NASA Astrophysics Data System (ADS)

    Feng, Z. C.; Xin, Ming

    2015-01-01

    In this paper, an energy pumping mechanism for locomotion is analysed. The pumping is accomplished by exerting forces perpendicular to the direction of motion. The paper attempts to demonstrate an interesting application of the classical mechanics to two sporting events: a person skating in a half pipe and a person travelling on a level surface on a skateboard. The equations of motion based on simplified mechanical models are derived using the Lagrange mechanics. The energy-pumping phenomenon is revealed through numerical simulations with simple pumping actions. The result presented in this paper can be used as an interesting class project in undergraduate mechanics or physics courses. It also motivates potential new applications of energy pumping in many engineering fields.

  4. A Low-Voltage Rotary Actuator Fabricated Using a Five-Level Polysilicon Surface Micromachining Technology

    SciTech Connect

    JAKUBCZAK II,JEROME F.; KRYGOWSKI,THOMAS W.; MILLER,SAMUEL L.; RODGERS,M. STEVEN; SNIEGOWSKI,JEFFRY J.

    1999-09-22

    The design, fabrication and characterization of a low-voltage rotary stepper motor are presented in this work. Using a five-level polysilicon MEMS technology, steps were taken to increase the capacitance over previous stepper motor designs to generate high torque at low voltages. A low-friction hub was developed to minimize frictional loads due to rubbing surfaces, producing an estimated resistive torque of about 6 pN-m. This design also allowed investigations into the potential benefit of using hard materials such as silicon nitride for lining of both the stationary and rotating hub components. The result is an electrostatic stepper motor capable of operation at less than six volts.

  5. Reactive ion etching-assisted surface-enhanced Raman scattering measurements on the single nanoparticle level

    SciTech Connect

    Wang, Si-Yi; Jiang, Xiang-Xu; Wei, Xin-Pan; Lee, Shuit-Tong E-mail: yaohe@suda.edu.cn; He, Yao E-mail: yaohe@suda.edu.cn; Xu, Ting-Ting

    2014-06-16

    Single-nanoparticle surface-enhanced Raman scattering (SERS) measurement is of essential importance for both fundamental research and practical applications. In this work, we develop a class of single-particle SERS approaches, i.e., reactive ion etching (RIE)-assisted SERS measurements correlated with scanning electron microscopy (SEM) strategy (RIE/SERS/SEM), enabling precise and high-resolution identification of single gold nanoparticle (AuNP) in facile and reliable manners. By using AuNP-coated silicon wafer and quartz glass slide as models, we further employ the developed RIE/SERS/SEM method for interrogating the relationship between SERS substrates and enhancement factor (EF) on the single particle level. Together with theoretical calculation using an established finite-difference-time-domain (FDTD) method, we demonstrate silicon wafer as superior SERS substrates, facilitating improvement of EF values.

  6. BOREAS Level-2 MAS Surface Reflectance and Temperature Images in BSQ Format

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Newcomer, Jeffrey (Editor); Lobitz, Brad; Spanner, Michael; Strub, Richard; Lobitz, Brad

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science Aircraft Data Acquisition Program focused on providing the research teams with the remotely sensed aircraft data products they needed to compare and spatially extend point results. The MODIS Airborne Simulator (MAS) images, along with other remotely sensed data, were collected to provide spatially extensive information over the primary study areas. This information includes biophysical parameter maps such as surface reflectance and temperature. Collection of the MAS images occurred over the study areas during the 1994 field campaigns. The level-2 MAS data cover the dates of 21-Jul-1994, 24-Jul-1994, 04-Aug-1994, and 08-Aug-1994. The data are not geographically/geometrically corrected; however, files of relative X and Y coordinates for each image pixel were derived by using the C130 navigation data in a MAS scan model. The data are provided in binary image format files.

  7. BOREAS Level-4c AVHRR-LAC Ten-Day Composite Images: Surface Parameters

    NASA Technical Reports Server (NTRS)

    Cihlar, Josef; Chen, Jing; Huang, Fengting; Nickeson, Jaime; Newcomer, Jeffrey A.; Hall, Forrest G. (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science Satellite Data Acquisition Program focused on providing the research teams with the remotely sensed satellite data products they needed to compare and spatially extend point results. Manitoba Remote Sensing Center (MRSC) and BOREAS Information System (BORIS) personnel acquired, processed, and archived data from the Advanced Very High Resolution Radiometer (AVHRR) instruments on the NOAA-11 and -14 satellites. The AVHRR data were acquired by CCRS and were provided to BORIS for use by BOREAS researchers. These AVHRR level-4c data are gridded, 10-day composites of surface parameters produced from sets of single-day images. Temporally, the 10-day compositing periods begin 11-Apr-1994 and end 10-Sep-1994. Spatially, the data cover the entire BOREAS region. The data are stored in binary image format files. Note: Some of the data files on the BOREAS CD-ROMs have been compressed using the Gzip program.

  8. Free surface flow through rock-fill dams analyzed by FEM with level set approach

    NASA Astrophysics Data System (ADS)

    Sharif, N. H.; Wiberg, N.-E.; Levenstam, M.

    A stabilized-finite element formulation is coupled with a level set technique for computations of incompressible non-linear flow with interfaces between two immiscible fluids. An interface capturing formulation (ICF) for non-linear, free surface, seepage flow in rock-fill dams is proposed. The formulation is derived for two- and three-dimensional flow within a fixed mesh domain. The resulting formulation is general and applicable for various steady and transient two-phase flow problems. FE-refinement is processed for the entire fixed mesh domains. A general solver is also reviewed for large and non-symmetric non-positive definite linear system of equations with the GMRES-update technique based on a Newton-iterative method. The computational procedure has been implemented in MATLAB. A comparison is performed between the 2-D computed test problem for coarse and refined meshes together with some proposed analytical solutions for nonlinear seepage flow with free surface in rock-fill dams. An expansion of the 2-D program code to a 3-D one for a rectangular rock-fill dam is also developed and simulated in MATLAB. The performance of the computations in 3-D is very promising and its opening the future for possible industrial applications using the same simple technique. Computations for a simple 3-D seepage flow problem with free surface in rock-fill dam are included in present paper. A general mesh generator and solver for large scale and complex 3-D flow problems in a real embankment dam is also under construction in C++.

  9. Impact of Nocturnal Low-Level Jets on Near-Surface Turbulence Kinetic Energy

    NASA Astrophysics Data System (ADS)

    Duarte, Henrique F.; Leclerc, Monique Y.; Zhang, Gengsheng; Durden, David; Kurzeja, Robert; Parker, Matthew; Werth, David

    2015-09-01

    We report on the role of low-level jets (LLJs) on the modulation of near-surface turbulence in the stable boundary layer, focusing on the behaviour of the transport terms of the turbulence kinetic energy (TKE) budget. We also examine the applicability of Monin-Obukhov similarity theory (MOST) in light of these terms. Using coincident near-surface turbulence and LLJ data collected over a three-month period in South Carolina, USA, we found that turbulence during LLJ periods was typically stronger and more well-developed in comparison with periods without a LLJ. We found a local imbalance in the near-surface TKE budget, in which the imbalance (residual) term was typically positive (i.e., energy gain) and nearly in equilibrium with buoyant consumption. Based on a comparison with previous studies, we assume that this residual term represents mostly pressure transport. We found the behaviour of the residual term to be better delineated in the presence of LLJs. We found shear production to adhere to MOST remarkably well during LLJs, except under very stable conditions. Gain of non-local TKE via pressure transport, likely consisting of large-scale fluctuations, could be the cause of the observed deviation from the MOST -less prediction. The fact that this deviation was observed for periods with well-developed turbulence with an inertial subrange slope close to indicates that such Kolmogorov turbulence is not a sufficient condition to guarantee the applicability of the MOST -less concept, as recently suggested in the literature. The implications of these results are discussed.

  10. Resonances and thresholds in the Rydberg-level population of multiply charged ions at solid surfaces

    NASA Astrophysics Data System (ADS)

    Nedeljković, Lj. D.; Nedeljković, N. N.

    1998-12-01

    We present a theoretical study of resonances and thresholds, two specific features of Rydberg-state formation of multiply charged ions (Z=6, 7, and 8) escaping a solid surface at intermediate velocities (v~1 a.u.) in the normal emergence geometry. The resonances are recognized in pronounced maxima of the experimentally observed population curves of Ar VIII ions for resonant values of the principal quantum number n=nres=11 and for the angular momentum quantum numbers l=1 and 2. Absence of optical signals in detectors of beam-foil experiments for n>nthr of S VI and Cl VII ions (with l=0, 1, and 2) and Ar VIII for l=0 is interpreted as a threshold phenomenon. An interplay between resonance and threshold effects is established within the framework of quantum dynamics of the low angular momentum Rydberg-state formation, based on a generalization of Demkov-Ostrovskii's charge-exchange model. In the model proposed, the Ar VIII resonances appear as a consequence of electron tunneling in the very vicinity of the ion-surface potential barrier top and at some critical ion-surface distances Rc. The observed thresholds are explained by means of a decay mechanism of ionic Rydberg states formed dominantly above the Fermi level EF of a solid conduction band. The theoretically predicted resonant and threshold values, nres and nthr of the principal quantum number n, as well as the obtained population probabilities Pnl=Pnl(v,Z), are in sufficiently good agreement with all available experimental findings.

  11. Evaluation of pressure transducers to measure surface level in the waste storage tanks

    SciTech Connect

    Peters, T.J.; Colson, J.B.

    1994-06-01

    This report describes the results of tests conducted at the Pacific Northwest Laboratory (PNL) to determine if pressure transducers can be used to measure the surface level in the waste tanks. A survey was first conducted to evaluate which, if any, commercially available pressure transducers were available that could meet the requirements for use in the waste tanks. More than 35 companies were contacted to determine if they manufactured a pressure transducer that could be used in the 101-SY waste tank. The three basic requirements for a pressure transducer for this application were that they were radiation-hardened, could withstand a caustic environment, and were certified to be intrinsically safe. No manufacturer was able to meet all three of these requirements with a commercially available product. Seven companies were able to meet the requirements for being radiation-hardened and being able to withstand the caustic environment. However, only two of the nine companies were willing to supply a pressure transducer for laboratory testing. The two pressure transducers that were tested in this program were the VEGA D36-38 from HiTech Technologies, Inc., and the KP-1911-A from Kaman Instrumentation Corporation. Pressure transducers operate on the principle that the pressure at the location of a sensor increases directly with the depth of the liquid above it. A liquid is required in order for these devices to operate. For these tests, water was first used to determine the ideal operation of the devices, then the devices were placed in a 101-SY waste tank simulant. The simulant had a specific gravity of 1.96 and had the consistency similar to the convective layer in the 101-SY waste tank. In order to determine the surface level with pressure transducers, the density of the material needs to be known.

  12. A Continuous Liquid-Level Sensor for Fuel Tanks Based on Surface Plasmon Resonance.

    PubMed

    Pozo, Antonio M; Pérez-Ocón, Francisco; Rabaza, Ovidio

    2016-01-01

    A standard problem in large tanks at oil refineries and petrol stations is that water and fuel usually occupy the same tank. This is undesirable and causes problems such as corrosion in the tanks. Normally, the water level in tanks is unknown, with the problems that this entails. We propose herein a method based on surface plasmon resonance (SPR) to detect in real time the interfaces in a tank which can simultaneously contain water, gasoline (or diesel) and air. The plasmonic sensor is composed of a hemispherical glass prism, a magnesium fluoride layer, and a gold layer. We have optimized the structural parameters of the sensor from the theoretical modeling of the reflectance curve. The sensor detects water-fuel and fuel-air interfaces and measures the level of each liquid in real time. This sensor is recommended for inflammable liquids because inside the tank there are no electrical or electronic signals which could cause explosions. The sensor proposed has a sensitivity of between 1.2 and 3.5 RIU(-1) and a resolution of between 5.7 × 10(-4) and 16.5 × 10(-4) RIU. PMID:27213388

  13. Levels of organochlorine pesticides and heavy metals in surface waters of Konya closed basin, Turkey.

    PubMed

    Aydin, Mehmet Emin; Ozcan, Senar; Beduk, Fatma; Tor, Ali

    2013-01-01

    The concentrations of organochlorine pesticides (OCPs), including α -, β -, γ -, and δ -hexachlorocyclohexane (HCH), heptachlor, heptachlor epoxide, dieldrin, aldrin, endrin, endrin aldehyde, endrin ketone, endosulfan I, endosulfan II, endosulfan sulfate, p,p'-DDE, p,p'-DDD, p,p'-DDT, methoxychlor, chlordane I, chlordane II, and heavy metals, such as As, Cr, Cu, Fe, Mn, and Ni in surface water samples from the Konya closed basin were determined to evaluate the level of contamination. Among all HCH isomers, β -HCH is the main isomer with a concentration range of 0.015-0.065 μ g/L. DDE, DDD, and DDT were almost determined in all samples, in which DDE isomer had the highest concentration ranged from not detected to 0.037 μ g/L. In all studied OCPs, aldrin showed the highest concentration at 0.220 μ g/L. The concentrations of heavy metals in water samples were observed with order: Mnlevels of both OCPs and heavy metals were also compared with other previously published data. PMID:23533363

  14. Levels of Organochlorine Pesticides and Heavy Metals in Surface Waters of Konya Closed Basin, Turkey

    PubMed Central

    Aydin, Mehmet Emin; Ozcan, Senar; Beduk, Fatma; Tor, Ali

    2013-01-01

    The concentrations of organochlorine pesticides (OCPs), including α-, β-, γ-, and δ-hexachlorocyclohexane (HCH), heptachlor, heptachlor epoxide, dieldrin, aldrin, endrin, endrin aldehyde, endrin ketone, endosulfan I, endosulfan II, endosulfan sulfate, p,p′-DDE, p,p′-DDD, p,p′-DDT, methoxychlor, chlordane I, chlordane II, and heavy metals, such as As, Cr, Cu, Fe, Mn, and Ni in surface water samples from the Konya closed basin were determined to evaluate the level of contamination. Among all HCH isomers, β-HCH is the main isomer with a concentration range of 0.015–0.065 μg/L. DDE, DDD, and DDT were almost determined in all samples, in which DDE isomer had the highest concentration ranged from not detected to 0.037 μg/L. In all studied OCPs, aldrin showed the highest concentration at 0.220 μg/L. The concentrations of heavy metals in water samples were observed with order: Mn < Cu < Ni < As < Cr < Fe. In some samples, As, Fe, and Cr concentrations exceeded the drinking water quality recommended by EU, US EPA, WHO, and Turkish Regulation, while Cu, Ni, and Mn concentrations are below the guideline values. The levels of both OCPs and heavy metals were also compared with other previously published data. PMID:23533363

  15. A Continuous Liquid-Level Sensor for Fuel Tanks Based on Surface Plasmon Resonance

    PubMed Central

    Pozo, Antonio M.; Pérez-Ocón, Francisco; Rabaza, Ovidio

    2016-01-01

    A standard problem in large tanks at oil refineries and petrol stations is that water and fuel usually occupy the same tank. This is undesirable and causes problems such as corrosion in the tanks. Normally, the water level in tanks is unknown, with the problems that this entails. We propose herein a method based on surface plasmon resonance (SPR) to detect in real time the interfaces in a tank which can simultaneously contain water, gasoline (or diesel) and air. The plasmonic sensor is composed of a hemispherical glass prism, a magnesium fluoride layer, and a gold layer. We have optimized the structural parameters of the sensor from the theoretical modeling of the reflectance curve. The sensor detects water-fuel and fuel-air interfaces and measures the level of each liquid in real time. This sensor is recommended for inflammable liquids because inside the tank there are no electrical or electronic signals which could cause explosions. The sensor proposed has a sensitivity of between 1.2 and 3.5 RIU−1 and a resolution of between 5.7 × 10−4 and 16.5 × 10−4 RIU. PMID:27213388

  16. Correlation and coherence analysis between sea surface temperature and altimetric sea level anomaly data

    NASA Astrophysics Data System (ADS)

    Zbylut-Górska, Maria; Kosek, Wiesław; Wnęk, Agnieszka; Młocek, Wojciech; Rutkowska, Agnieszka; Popiński, Waldemar; Niedzielski, Tomasz

    2016-04-01

    One of the main causes of the sea level variations is the steric effect caused by changes of local sea surface temperature (SST). To show how the altimetric Sea Level Anomaly (SLA) data are related to the SST data, correlation coefficients between them as a function of geographic location were computed. The analysis showed a high positive correlation (about 0.7), especially in the Northern and South-Eastern parts of the Pacific Ocean and a large part of the Atlantic Ocean. There is a negative correlation of about 0.5 in the South-East part of Indian Ocean, on the Arafura Sea and the Red Sea. In addition the time-frequency coherence and semblance functions between the SLA and SST data were calculated using Fourier transform band pass filter. The maps of such coherence and semblance functions in frequency bands corresponding to the annual oscillation and its integer multiplicities were computed. The most imporntat contribution to the correlation coefficient values has the annual oscillation in the SST and SLA data.

  17. Non-contact ultrasonic acquisition of femtosecond laser-driven ablative Mbar-level shock waves on Ti alloy surface

    NASA Astrophysics Data System (ADS)

    Ageev, E. I.; Kudryashov, S. I.; Nikonorov, N. V.; Nuryev, R. K.; Petrov, A. A.; Samokhvalov, A. A.; Veiko, V. P.

    2016-02-01

    Mbar-level ablative plume pressures, produced by single-shot femtosecond laser ablation of a dry Ti alloy surface and driving shock waves in air and in the solid target, were characterized using non-contact broad-band ultrasonic measurements. X-ray diffraction measurements reveal the resulting shock-wave induced sub-GPa residual compressive stresses over multi-micrometer depths inside the target, indicating GPa-level residual compressive stresses on its surface.

  18. Occurrence and levels of polybrominated diphenyl ethers in surface sediments from the Yellow River Estuary, China.

    PubMed

    Yuan, Zijiao; Liu, Guijian; Lam, Michael Hon Wah; Liu, Houqi; Da, Chunnian

    2016-05-01

    A total of 21 surface sediments collected from the Yellow River Estuary, China were analyzed for 40 kinds of polybrominated diphenyl ethers (PBDEs) using gas chromatography-mass spectrometry (GC-MS). Their levels, spatial distribution, congener profiles and possible sources were investigated. Only ten congeners were detected in the sediments. The total concentrations of the lower brominated BDEs (∑PBDEslow, PBDEs excluding BDE 209) and BDE 209 ranged from 0.482 ng/g to 1.07 ng/g and 1.16-5.40 ng/g, with an average value of 0.690 and 2.79 ng/g, respectively, which were both at the low end of the global contamination level. The congener profiles were dominated by BDE 209, with the average value accounting for 79.2% of the total PBDEs in the sediment samples. Among the nine lower brominated BDE congeners, BDE 47, 99 and 183 had high abundances. Although the commercial Penta/Octa-BDE products have been banned in most countries, the residual commercial Penta/Octa/Deca-BDE products and the debromination of highly brominated BDE compounds such as BDE 209 were still found to be the possible sources for the trace level of PBDEs in the present study area. In spite of the gradual removal of the commercial PBDEs in the world, the present research results further suggested that scientific attention should not be reduced on the issue of environmental contamination caused by these outdated chemical compounds. PMID:26845362

  19. Comparisons of predicted steady-state levels in rooms with extended- and local-reaction bounding surfaces

    NASA Astrophysics Data System (ADS)

    Hodgson, Murray; Wareing, Andrew

    2008-01-01

    A combined beam-tracing and transfer-matrix model for predicting steady-state sound-pressure levels in rooms with multilayer bounding surfaces was used to compare the effect of extended- and local-reaction surfaces, and the accuracy of the local-reaction approximation. Three rooms—an office, a corridor and a workshop—with one or more multilayer test surfaces were considered. The test surfaces were a single-glass panel, a double-drywall panel, a carpeted floor, a suspended-acoustical ceiling, a double-steel panel, and glass fibre on a hard backing. Each test surface was modeled as of extended or of local reaction. Sound-pressure levels were predicted and compared to determine the significance of the surface-reaction assumption. The main conclusions were that the difference between modeling a room surface as of extended or of local reaction is not significant when the surface is a single plate or a single layer of material (solid or porous) with a hard backing. The difference is significant when the surface consists of multilayers of solid or porous material and includes a layer of fluid with a large thickness relative to the other layers. The results are partially explained by considering the surface-reflection coefficients at the first-reflection angles.

  20. Direct Measurements of Fermi Level Pinning at the Surface of Intrinsically n-Type InGaAs Nanowires.

    PubMed

    Speckbacher, Maximilian; Treu, Julian; Whittles, Thomas J; Linhart, Wojciech M; Xu, Xiaomo; Saller, Kai; Dhanak, Vinod R; Abstreiter, Gerhard; Finley, Jonathan J; Veal, Tim D; Koblmüller, Gregor

    2016-08-10

    Surface effects strongly dominate the intrinsic properties of semiconductor nanowires (NWs), an observation that is commonly attributed to the presence of surface states and their modification of the electronic band structure. Although the effects of the exposed, bare NW surface have been widely studied with respect to charge carrier transport and optical properties, the underlying electronic band structure, Fermi level pinning, and surface band bending profiles are not well explored. Here, we directly and quantitatively assess the Fermi level pinning at the surfaces of composition-tunable, intrinsically n-type InGaAs NWs, as one of the prominent, technologically most relevant NW systems, by using correlated photoluminescence (PL) and X-ray photoemission spectroscopy (XPS). From the PL spectral response, we reveal two dominant radiative recombination pathways, that is, direct near-band edge transitions and red-shifted, spatially indirect transitions induced by surface band bending. The separation of their relative transition energies changes with alloy composition by up to more than ∼40 meV and represent a direct measure for the amount of surface band bending. We further extract quantitatively the Fermi level to surface valence band maximum separation using XPS, and directly verify a composition-dependent transition from downward to upward band bending (surface electron accumulation to depletion) with increasing Ga-content x(Ga) at a crossover near x(Ga) ∼ 0.2. Core level spectra further demonstrate the nature of extrinsic surface states being caused by In-rich suboxides arising from the native oxide layer at the InGaAs NW surface. PMID:27458736

  1. Analysis of Ultra High Resolution Sea Surface Temperature Level 4 Datasets

    NASA Technical Reports Server (NTRS)

    Wagner, Grant

    2011-01-01

    Sea surface temperature (SST) studies are often focused on improving accuracy, or understanding and quantifying uncertainties in the measurement, as SST is a leading indicator of climate change and represents the longest time series of any ocean variable observed from space. Over the past several decades SST has been studied with the use of satellite data. This allows a larger area to be studied with much more frequent measurements being taken than direct measurements collected aboard ship or buoys. The Group for High Resolution Sea Surface Temperature (GHRSST) is an international project that distributes satellite derived sea surface temperatures (SST) data from multiple platforms and sensors. The goal of the project is to distribute these SSTs for operational uses such as ocean model assimilation and decision support applications, as well as support fundamental SST research and climate studies. Examples of near real time applications include hurricane and fisheries studies and numerical weather forecasting. The JPL group has produced a new 1 km daily global Level 4 SST product, the Multiscale Ultrahigh Resolution (MUR), that blends SST data from 3 distinct NASA radiometers: the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Very High Resolution Radiometer (AVHRR), and the Advanced Microwave Scanning Radiometer ? Earth Observing System(AMSRE). This new product requires further validation and accuracy assessment, especially in coastal regions.We examined the accuracy of the new MUR SST product by comparing the high resolution version and a lower resolution version that has been smoothed to 19 km (but still gridded to 1 km). Both versions were compared to the same data set of in situ buoy temperature measurements with a focus on study regions of the oceans surrounding North and Central America as well as two smaller regions around the Gulf Stream and California coast. Ocean fronts exhibit high temperature gradients (Roden, 1976), and thus

  2. Study to investigate the trace levels of contamination on surfaces when narcotic contraband is concealed in a vehicle

    NASA Astrophysics Data System (ADS)

    Wilson, Rod; Brittain, Alan H.

    1997-01-01

    When a vehicle is used to transport narcotic contraband material trace levels of that material can be found on surfaces of the vehicle, people associated with the vehicle and surface they contact. The detection of these trace levels can help to target vehicles associated with the smuggling of the contraband. A study to determine the typical levels of narcotic material that can be detected from these surfaces has been performed by personnel from Graseby, using a variety of drug materials. The size and packaging of the drug materials has been prepared to try to reflect that typically found in smuggling operations. These tests show that for all hard drugs easily detectable traces of drug material can be found on the vehicle, the proxy and secondary surfaces handled by the proxy. For detection of cannabis, the condition of the original material had a great bearing ont he reliability of detection.

  3. Strong compensation hinders the p-type doping of ZnO: a glance over surface defect levels

    NASA Astrophysics Data System (ADS)

    Huang, B.

    2016-07-01

    We propose a surface doping model of ZnO to elucidate the p-type doping and compensations in ZnO nanomaterials. With an N-dopant, the effects of N on the ZnO surface demonstrate a relatively shallow acceptor level in the band gap. As the dimension of the ZnO materials decreases, the quantum confinement effects will increase and render the charge transfer on surface to influence the shifting of Fermi level, by evidence of transition level changes of the N-dopant. We report that this can overwhelm the intrinsic p-type conductivity and transport of the ZnO bulk system. This may provide a possible route of using surface doping to modify the electronic transport and conductivity of ZnO nanomaterials.

  4. Measurements of liquid surface fluctuations at sub-shot-noise levels with Michelson interferometry

    NASA Astrophysics Data System (ADS)

    Mitsui, Takahisa; Aoki, Kenichiro

    2013-04-01

    Surface fluctuation spectra of liquids are measured to unprecedented precision, down to 3 orders of magnitude below the shot-noise level using averaged correlations of interferometry measurements. This allows us to investigate the limits in our current theoretical understanding of these phenomena. The spectrum derived from hydrodynamical considerations agrees well with the observed results for water. However, for oil, deviations are seen at high frequencies (≳1 MHz), perhaps indicating its more complex underlying physics. The measurements are made possible by dualizing the Michelson interferometry measurements and employing the averaged correlation of signals, in which the shot noise is statistically reduced. The method works in the presence of the quantum noise of a coherent state of light. The optical part of the experimental setup is essentially the same as that of Michelson interferometry so that the method can be applied when Michelson interferometry can be used. Furthermore, the measurement method requires a relatively low light power and a short time so that it has a wide range of applicability.

  5. Levels of methylmercury and controlling factors in surface sediments of the Carson River system, Nevada

    SciTech Connect

    Chen, Y.; Bonzongo, J.C.; Miller, G.C.

    1995-12-31

    Spatial and temporal distribution of MeHg, as well as, its relationships with both the biotic and abiotic activities, were determined in surficial sediments collected from a river-reservoir system, severely impacted by Hg-contaminated mine wastes. Despite the fact that total mercury concentrations in surface sediments of the Carson River system were in the {mu}g.g{sup -1} range, levels of MeHg varied from {approximately}1 to 28 ng Hg.g{sup -1} dry weight, representing less than 3% of Total-Hg. Positive relationships were obtained between MeHg concentrations and both the chemical activity and general rate of biotic activity, suggesting the contribution of both the abiotic and biotic processes in the production of MeHg in natural environments, the latter being more important and more significant. Laboratory investigations showed that rates of MeHg production in sediments of the Carson River were affected by factors related to peculiarities of this aquatic system.

  6. High-level ab initio potential energy surfaces and vibrational energies of H2CS

    NASA Astrophysics Data System (ADS)

    Yachmenev, Andrey; Yurchenko, Sergei N.; Ribeyre, Tristan; Thiel, Walter

    2011-08-01

    Six-dimensional (6D) potential energy surfaces (PESs) of H2CS have been generated ab initio using the recently proposed explicitly correlated (F12) singles and doubles coupled cluster method including a perturbational estimate of connected triple excitations, CCSD(T)-F12b [T. B. Adler, G. Knizia, and H.-J. Werner, J. Chem. Phys. 127, 221106 (2007)] in conjunction with F12-optimized correlation consistent basis sets. Core-electron correlation, high-order correlation, scalar relativistic, and diagonal Born-Oppenheimer terms were included as additive high-level (HL) corrections. The resulting 6D PESs were represented by analytical functions which were used in variational calculations of the vibrational term values below 5000 cm-1. The best PESs obtained with and without the HL corrections, VQZ-F12* HL and VQZ-F12*, reproduce the fundamental vibrational wavenumbers with mean absolute deviations of 1.13 and 1.22 cm-1, respectively. A detailed analysis of the effects of the HL corrections shows how the VQZ-F12 results benefit from error cancellation. The present purely ab initio PESs will be useful as starting points for empirical refinements towards an accurate "spectroscopic" PES of H2CS.

  7. Measurements of liquid surface fluctuations at sub-shot-noise levels with Michelson interferometry.

    PubMed

    Mitsui, Takahisa; Aoki, Kenichiro

    2013-04-01

    Surface fluctuation spectra of liquids are measured to unprecedented precision, down to 3 orders of magnitude below the shot-noise level using averaged correlations of interferometry measurements. This allows us to investigate the limits in our current theoretical understanding of these phenomena. The spectrum derived from hydrodynamical considerations agrees well with the observed results for water. However, for oil, deviations are seen at high frequencies (>/~1 MHz), perhaps indicating its more complex underlying physics. The measurements are made possible by dualizing the Michelson interferometry measurements and employing the averaged correlation of signals, in which the shot noise is statistically reduced. The method works in the presence of the quantum noise of a coherent state of light. The optical part of the experimental setup is essentially the same as that of Michelson interferometry so that the method can be applied when Michelson interferometry can be used. Furthermore, the measurement method requires a relatively low light power and a short time so that it has a wide range of applicability. PMID:23679425

  8. Semi-Automated Detection of Surface Degradation on Bridges Based on a Level Set Method

    NASA Astrophysics Data System (ADS)

    Masiero, A.; Guarnieri, A.; Pirotti, F.; Vettore, A.

    2015-08-01

    Due to the effect of climate factors, natural phenomena and human usage, buildings and infrastructures are subject of progressive degradation. The deterioration of these structures has to be monitored in order to avoid hazards for human beings and for the natural environment in their neighborhood. Hence, on the one hand, monitoring such infrastructures is of primarily importance. On the other hand, unfortunately, nowadays this monitoring effort is mostly done by expert and skilled personnel, which follow the overall data acquisition, analysis and result reporting process, making the whole monitoring procedure quite expensive for the public (and private, as well) agencies. This paper proposes the use of a partially user-assisted procedure in order to reduce the monitoring cost and to make the obtained result less subjective as well. The developed method relies on the use of images acquired with standard cameras by even inexperienced personnel. The deterioration on the infrastructure surface is detected by image segmentation based on a level sets method. The results of the semi-automated analysis procedure are remapped on a 3D model of the infrastructure obtained by means of a terrestrial laser scanning acquisition. The proposed method has been successfully tested on a portion of a road bridge in Perarolo di Cadore (BL), Italy.

  9. Pesticide levels in surface waters in an agricultural-forestry basin in Southern Chile.

    PubMed

    Palma, Graciela; Sánchez, Alejandra; Olave, Yohana; Encina, Francisco; Palma, Rodrigo; Barra, Ricardo

    2004-11-01

    Residues of five pesticides in surface water were surveyed during 2001 and 2003 in the Traiguen river basin in Southern Chile. Simazine, hexazinone, 2,4-D, picloram herbicides and carbendazim fungicide were selected through a pesticide risk classification index. Six sampling stations along the river were set up based on agricultural and forestry land use. The water sampling was carried out before and after the pesticide application periods and in correspondence to some rain events. Pesticides were analyzed by HPLC with DAD detection in a multiresidue analysis. During 2001, in the first sampling campaign (March), the highest concentrations of pesticides were 3.0 microg l(-1) for simazine and hexazinone and 1.8 microg l(-1) for carbendazim. In the second sampling (September), the highest concentration were 9.7 microg l(-1) for 2,4-D, 0.3 microg l(-1) for picloram and 0.4 microg l(-1) for carbendazim. In the last sampling period (December), samples indicated contamination with carbendazim fungicide at levels of up to 1.2 microg l(-1). In sampling carried out on May 2003, no pesticides were detected. In October 2003, the highest concentrations of pesticides were 4.5 microg l(-1) for carbendazim and 2.9 microg l(-1) for 2,4-D. Data are discussed in function of land use and application periods of the products, showing a clear seasonal pattern pollution in the Traiguen river. Risk assessment for these pesticides was calculated by using a risk quotient (RQ = PNEC/PEC). For picloram the calculated RQ < was 0, which indicates that no adverse effects may occur due to the exposure to this herbicide in the Traiguen river basin. For 2,4-D, simazine, hexazinone, carbendazim RQ > 1, meaning that adverse effects could occur and it is necessary to reduce pesticide exposure in surface waters. It is recommended to continue with a pesticide monitoring program and the implementation of ecotoxicological testing with local and standardized species in order to consider the probability of

  10. Measurement of Ambient Ammonia and Surface-level Meteorological Forcing Variables near an Agricultural Emission Source

    NASA Astrophysics Data System (ADS)

    Myles, L.; Heuer, M. W.

    2012-12-01

    Atmospheric ammonia (NH3) is a reduced form of reactive nitrogen that is primarily emitted from agricultural activities. NH3 volatilizes from animal waste and fertilized land directly into the atmosphere where it can either react with other gases to form fine particulate matter or deposit on surfaces through air-surface exchange processes. Field measurements in different ecosystems and under various conditions are necessary to improve the understanding of the complex relationships between ambient NH3 and meteorological parameters, such as temperature and relative humidity, which influence volatilization rates and ultimately, ambient concentrations near emission sources. However, the measurement of ambient NH3 is challenging. NH3 is hydroscopic and reactive, and measurement techniques are subject to errors caused by sampling artifacts and other interferences. Recent advancements have led to improved techniques that allow real-time measurement of ambient NH3. A cavity ring-down spectrometer was deployed at a cattle research facility in Knoxville, TN during spring 2012 to measure ambient NH3, and meteorological instrumentation was collocated to measure 3-D winds, temperature, relative humidity, precipitation and other parameters (z = 2 m). The study site was rolling pasture typical of the eastern Tennessee Valley and included two large barns and approximately 30-40 cattle. Daytime ambient NH3 averaged 15-20 ppb most days with lows of approximately 7 ppb at night. Higher concentrations (greater than 50 ppb) seemed to correlate with higher temperatures (greater than 27 C), although the data are not consistent. Several instances of 100 ppb concentrations were measured when temperatures were high and winds were from the direction of the barns. Overall, the study shows that ambient NH3 levels near agricultural emission sources may vary greatly with time and a variety of factors, including meteorological conditions. The data support the need for real-time measurements of NH