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Sample records for 242-a evaporator process

  1. Process Control Plan for 242A Evaporator Campaign

    SciTech Connect

    LE, E.Q.

    2000-04-06

    The wastes in tanks 107-AP and 108-AP are designated as feed for 242-A Evaporator Campaign 2000-1, which is currently scheduled for the week of April 17, 2000. Waste in tanks 107-AP and 108-AP is predominantly comprised of saltwell liquor from 200 West Tank Farms.

  2. Process control plan for 242-A Evaporator Campaign 94-2

    SciTech Connect

    Le, E.Q.

    1994-09-01

    242-A Evaporator Campaign 94-2 will process approximately 3.42 million gallons of dilute waste from tanks 101-AP, 107-AP, 108AP, 102-AW, and 106-AW. The process control plant describes activities which will occur during Campaign 94-2. This document also addresses compliance with the tank farm waste compatibility program, the 242-A radiological source term, the criticality prevention specifications, and effluent discharge limits.

  3. Process control plan for 242-A Evaporator Campaign 95-1

    SciTech Connect

    Le, E.Q.; Guthrie, M.D.

    1995-05-18

    The wastes from tanks 106-AP, 107-AP, and 106-AW have been selected to be candidate feed wastes for Evaporator Campaign 95-1. The wastes in tank 106-AP and 107-AP are primarily from B-Plant strontium processing and PUREX neutralized cladding removal, respectively. The waste in tank 106-AW originated primarily from the partially concentrated product from 242-A Evaporator Campaign 94-2. Approximately 8.67 million liters of waste from these tanks will be transferred to tank 102-AW during the campaign. Tank 102-AW is the dedicated waste feed tank for the evaporator and currently contains 647,000 liters of processable waste. The purpose of the 242-A Evaporator Campaign 95-1 Process Control Plan (hereafter referred to as PCP) is to certify that the wastes in tanks 106-AP, 107-AP, 102-AW, and 106-AW are acceptable for processing through evaporator and provide a general description of process strategies and activities which will take place during Campaign 95-1. The PCP also summarizes and presents a comprehensive characterization of the wastes in these tanks.

  4. Project C-018H, 242-A Evaporator/PUREX Plant Process Condensate Treatment Facility, functional design criteria. Revision 3

    SciTech Connect

    Sullivan, N.

    1995-05-02

    This document provides the Functional Design Criteria (FDC) for Project C-018H, the 242-A Evaporator and Plutonium-Uranium Extraction (PUREX) Plant Condensate Treatment Facility (Also referred to as the 200 Area Effluent Treatment Facility [ETF]). The project will provide the facilities to treat and dispose of the 242-A Evaporator process condensate (PC), the Plutonium-Uranium Extraction (PUREX) Plant process condensate (PDD), and the PUREX Plant ammonia scrubber distillate (ASD).

  5. Engineering work plan for implementing the Process Condensate Recycle Project at the 242-A evaporator

    SciTech Connect

    Haring, D.S.

    1995-02-02

    The 242-A Evaporator facility is used to reduce the volume of waste stored in the Hanford double shell tanks. This facility uses filtered raw water for cooling, de-entrainment pad sprays, pump seal water, and chemical tank make-up. Some of these uses result in the introduction of filtered raw water into the process, thus increasing the volume of waste requiring evaporation and subsequent treatment by the 200 East Effluent Treatment Facility. The pump seal water and the de-entrainment pad spray systems were identified as candidates for a waste minimization upgrade. This work plan describes the activities associated with the design, installation, testing and initial operation of the process condensate recycle system. Implementation of the process condensate recycle system will permit the use of process condensate in place of raw water for the de-entrainment pad sprays and pump seals. This will reduce the amount of low-level liquid waste and generated during facility operation through source reduction and recycling.

  6. 242-A evaporator safety analysis report

    SciTech Connect

    CAMPBELL, T.A.

    1999-05-17

    This report provides a revised safety analysis for the upgraded 242-A Evaporator (the Evaporator). This safety analysis report (SAR) supports the operation of the Evaporator following life extension upgrades and other facility and operations upgrades (e.g., Project B-534) that were undertaken to enhance the capabilities of the Evaporator. The Evaporator has been classified as a moderate-hazard facility (Johnson 1990). The information contained in this SAR is based on information provided by 242-A Evaporator Operations, Westinghouse Hanford Company, site maintenance and operations contractor from June 1987 to October 1996, and the existing operating contractor, Waste Management Hanford (WMH) policies. Where appropriate, a discussion address the US Department of Energy (DOE) Orders applicable to a topic is provided. Operation of the facility will be compared to the operating contractor procedures using appropriate audits and appraisals. The following subsections provide introductory and background information, including a general description of the Evaporator facility and process, a description of the scope of this SAR revision,a nd a description of the basic changes made to the original SAR.

  7. 242-A evaporator vacuum condenser system

    SciTech Connect

    Smith, V.A.

    1994-09-28

    This document is written for the 242-A evaporator vacuum condenser system (VCS), describing its purpose and operation within the evaporator. The document establishes the operating parameters specifying pressure, temperature, flow rates, interlock safety features and interfacing sub-systems to support its operation.

  8. 1998 242-A interim evaporator tank system integrity assessment plan

    SciTech Connect

    Jensen, C.E.

    1998-03-31

    Portions of the 242-A Evaporator on the Hanford Site must be assessed to meet the requirements of the Washington State Department of Ecology`s Dangerous Waste Regulation, Washington Administrative Code (WAC) 173-303. The assessment is limited to the provisions of Section 173-303-640. This Integrity Assessment Plan (IAP) identifies tasks which will be performed during the assessment phase and describes the intended assessment techniques. The 242-A Evaporator facility processes waste solutions from most of the operating laboratories and plants of the Hanford Site. The waste solutions are concentrated in the evaporator to a slurry of liquid and crystallized salts. This concentrated slurry is returned to the Tank Farms at a significantly reduce volume. The water vapor from the evaporation process is condensed, filtered, and can be pumped through an ion exchange bed before transfer to a retention basin. The non-condensable portion of the vapor is filtered and continuously monitored before venting to the atmosphere. The 242-A Evaporator will be assessed as seven subsystems. Four of the subsystems store, transport or treat Washington State Dangerous wastes, the other three subsystems are integral parts of the process, however, they do not directly store, transfer, or treat listed dangerous wastes. The facility will be inspected, tested, and analyzed through this assessment. The seven subsystems, defined in detail in Appendix B, are: Evaporator Process and Slurry Subsystem; Vapor Condenser Subsystem; Vessel Vent Subsystem; Process Condensate Subsystem; Steam Condensate Subsystem; Raw Water Disposal Subsystem; and Building and Secondary Containment Subsystem.

  9. 242-A Evaporator waste analysis plan. Revision 4

    SciTech Connect

    Basra, T.S.; Mulkey, C.H.

    1994-09-29

    This waste analysis plan (WAP) provides the plan for obtaining information needed for proper waste handling and processing in the 242-A Evaporator located on the Hanford Site. Regulatory and safety issues are addressed by establishing boundary conditions for waste received and treated at the 242-A Evaporator. The boundary conditions are set by establishing limits for items such as potential exothermic reactions, waste compatibility, and control of vessel vent organic emissions. Boundary conditions are also set for operational considerations and to ensure waste acceptance at receiving facilities. The issues that are addressed in this plan include prevention of exotherms in the waste, waste compatibility, vessel vent emissions, and compatibility with the liner in the Liquid Effluent Retention Facility (LERF). The 242-A Evaporator feed stream is separated into two liquid streams: a concentrated slurry stream and a process condensate. A gaseous exhaust stream is also produced. The slurry contains the majority of the radionuclides and inorganic constituents. This stream is pumped back to the double shell tanks (DSTs) and stored for further treatment after being concentrated to target levels. The process condensate (PC) is primarily water that contains trace amounts of organic material and a greatly reduced concentration of radionuclides. The process condensate is presently stored in the (LERF) until it can be further processed in the Effluent Treatment Facility once it is operational.

  10. 242-A evaporator quality assurance project plan: Revision 1

    SciTech Connect

    Tucker, B.J.

    1994-11-04

    The scope of this quality assurance project plan (Plan) is sampling and analytical services including, but not limited to, sample receipt, handling and storage, analytical measurements, submittal of data deliverables, archiving selected portions of samples, returning unneeded sample material to Westinghouse Hanford Company (WHC), and/or sample disposal associated with candidate feed samples and process condensate compliance samples. Sampling and shipping activities are also included within the scope. The purpose of this project is to provide planning, implementation, and assessment guidance for achieving established data quality objectives measurement parameters. This Plan requires onsite and offsite laboratories to conform to that guidance. Laboratory conformance will help ensure that quality data are being generated and therefore, that the 242-A evaporator is operating in a safe and compliant manner. The 242-A evaporator feed stream originates from double-shell tanks (DSTs) identified as candidate feed tanks. The 242-A evaporator reduces the volume of aqueous waste contained in DSTs by boiling off water and sending it to the Liquid Effluent Retention Facility (LERF) storage basin before further treatment. The slurry product is returned to DSTs. Evaporation results in considerable savings by reducing the volume of mixed waste for disposal.

  11. 242-A Evaporator Waste Analysis Plan. Revision 5

    SciTech Connect

    Basra, T.S.

    1995-04-13

    This Waste Analysis Plan (WAP) provides the plan for obtaining information needed for proper waste handling and processing in the 242-A Evaporator (Evaporator) located on the Hanford Site. In particular it addresses analysis necessary to manage the waste according to Washington Administrative Code (WAC) 173-303 and Parts 264 and 265 of the Code of Federal Regulations (CFR). Regulatory and safety issues are addressed by establishing boundary conditions for waste received and treated at the 242-A Evaporator. The boundary conditions are set by establishing limits for items such as potential exothermic reactions, waste compatibility, and control of vessel vent organic emissions. Boundary conditions are also set for operational considerations and to ensure waste acceptance at receiving facilities. The issues that are addressed in this plan include prevention of exotherms in the waste, waste compatibility, and vessel vent emissions. Samples from the other streams associated with the Evaporator are taken as required by Process Control Plans but are excluded from this plan because either the streams do not contain dangerous waste or the analyses are not required by WAC 173-303-300.

  12. Technical support for authorization of 242-A evaporator campaign 97-2, Hanford Site, Richland, Washington

    SciTech Connect

    Daling, P.M.; Lavender, J.C.

    1997-07-01

    An analysis was performed to determine the acceptability of processing 242-A Evaporator/Crystallizer Campaign 97-2 feed. Inhalation unit liter doses (ULDs) were calculated using the methods and data described in the Tank Waste Remediation System Basis for Interim Operation (TWRS BIO) and 242-A Evaporator/Crystallizer Safety Analysis Report. The ULD calculated for the Campaign 97-2 slurry was found to be less than the TWRS BIO evaporator slurry ULD and so would be within the analyzed safety envelope defined in the TWRS BIO. The Evaporator slurry ULD established in the TWRS BIO and supporting documents was calculated using the bounding source strength defined in the 242-A Evaporator SAR. Consequently, the risks and consequences associated with the Campaign 97-2 slurry would be lower than those already accepted by DOE and documented in the TWRS BIO and 242-A Evaporator SAR. The direct radiation exposures from formation of a liquid pool of Campaign 97-2 slurry were demonstrated to be less than the exposures from a pool formed by bounding source strength evaporator slurry as defined in the 242-A Evaporator SAR. This was demonstrated via a comparison of the Campaign 97-2 slurry composition and the 242-A Evaporator SAR bounding source strength. It was concluded that the direct radiation exposures from Campaign 97-2 slurry would be within the analyzed safety envelope in the 242-A Evaporator SAR.

  13. 242-A Campaign 99-1 process control plan

    SciTech Connect

    LE, E.Q.

    1999-08-25

    242-A Evaporator 99-1 will process approximately one million gallons of waste from tank 102-AW in June 1999. The process control Plan provides a general description of activities, which will occur during 242-A Evaporator Campaign 99-1 and to document analyses conducted to demonstrate that 102-AW waste is acceptable for processing. Predict is a registered trademark of Risk Decisions England Corporation, United Kingdom.

  14. THE FLAMMABILITY ANALYSIS AND TIME TO REACH LOWER FLAMMABILITY LIMIT CALCULATIONS ON THE WASTE EVAPORATION AT 242-A EVAPORATOR

    SciTech Connect

    HU TA

    2007-10-31

    This document describes the analysis of the waste evaporation process on the flammability behavior. The evaluation calculates the gas generation rate, time to reach 25% and 100% of the lower flammability limit (LFL), and minimum ventilation rates for the 242-A Evaporator facility during the normal evaporation process and when vacuum is lost. This analysis performs flammability calculations on the waste currently within all 28 double-shell tanks (DST) under various evaporation process conditions to provide a wide spectrum of possible flammable gas behavior. The results of this analysis are used to support flammable gas control decisions and support and upgrade to Documented Safety Analysis for the 242-A Evaporator.

  15. Waste volume reduction factors for potential 242-A evaporator feed

    SciTech Connect

    Sederburg, J.P.

    1995-05-04

    Double-shell tank (DST) storage space requirements have been shown to be highly dependent on the end point of 242-A operations. Consequences to the DST of various waste volumes, and concentrations, are evaluated. Only waste streams that are currently planned to be stored in the DST system before the year 2004 are discussed. As of January 1, 1995, approximately 27-million L (7.2-million gal) of dilute wastes are stored in the DSTs available for evaporator processing. Waste streams planned to be transferred to the DSTs before December 31, 2004, are identified. The DST volume for storing slurry from these wastes is presented in this document. At a final slurry specific gravity of -1.35, 22.5-million L (5.93-million gal) of DST space would be needed on December 31, 2004, to store the product from evaporator processing of these feedstocks. The expected volume needed if the resultant slurry were concentrated to the traditional double-shell slurry feed (DSSF) phase boundary (a specific gravity of {approximately}1.5) would be 17.7-million L (4.67-million gal). An additional 4.8-million L (1.26-million gal) is therefore needed if these wastes are concentrated to a specific gravity of 1.35 instead of the DSSF limit.

  16. Analytical services: 222-S characterization of 242-A Evaporator Slurry, Campaign 94-1. Addendum 1A

    SciTech Connect

    Not Available

    1994-09-13

    During the 242-A Evaporator`s 94-1 campaign, five process samples were collected from the slurry stream for waste characterization. The five samples were collected over a 36 day time span, respectively on May 4, May 9, May 16, May 23, and June 9, 1994. Sample collections were performed per the protocol described in 242-A Evaporator Waste Analysis Plan, WHC-SD-WM-EV-060, Rev. 3 and in 242-A Evaporator Quality Assurance Project Plan, WHC-SD-WM-QAPP-009, Rev. 0. Slurry waste was characterized chemically and radiochemically by the Westinghouse Hanford Company, 222-S Laboratory as directed.

  17. Functional design criteria for the 242-A evaporator and PUREX (Plutonium-Uranium Extraction) Plant condensate interim retention basin

    SciTech Connect

    Cejka, C.C.

    1990-01-01

    This document contains the functional design criteria for a 26- million-gallon retention basin and 10 million gallons of temporary storage tanks. The basin and tanks will be used to store 242-A Evaporator process condensate, the Plutonium-Uranium Extraction (PUREX) Plant process distillate discharge stream, and the PUREX Plant ammonia scrubber distillate stream. Completion of the project will allow both the 242-A Evaporator and the PUREX Plant to restart. 4 refs.

  18. Organic emission calculations for the 242-A evaporator vessel vent system

    SciTech Connect

    Bowman, M.R.

    1996-06-20

    This document contains historical calculations originally published in the 242-A Evaporator Dangerous Waste Permit Application, DOE/RL-90-42, Rev 0. They are being released as a supporting document, along with brief explanatory information, to be used as a reference in Rev 1 of the permit application and in other supporting documents, such as the 242-A Evaporator Data Quality Objectives.

  19. Atmospheric dispersion of ammonia accidentally released from the 242-A Evaporator, Hanford Site, Richland, Washington

    SciTech Connect

    Daling, P.M.; Lavender, J.C.

    1997-11-01

    Two errors have been identified in the authorization basis for the 242-A Evaporator at the Hanford Site. These errors, which appear in the 242-A Evaporator/Crystallizer Final Safety Analysis Report analysis of ammonia gas concentrations accidentally released from the 242-A Evaporator, are: (1) the vessel ventilation system flow rate used in the previous calculations is a factor of ten higher than the actual flow rate, and (2) the previous calculations did not account for the ammonia source term reduction that would occur via condensation of ammonia vapors, which will remove a large fraction of the ammonia from the exhaust gas stream. The purpose of this document is to correct these errors and recalculate the maximum ground-level concentrations of ammonia released to the environment as a result of potential errors in blending Evaporator feed. The errors offset each other somewhat, so it is unlikely that the 242-A Evaporator has operated outside its current authorization basis. However, the errors must be corrected and the results incorporated into a revision of the 242-A Evaporator/Crystallizer Safety Analysis Report, WHC-SD-WM-SAR-023. An EPA-approved atmospheric dispersion model, SCREEN3, was used to recalculate the maximum ground-level concentrations of ammonia that would be released from the 242-A Evaporator as a result of a feed-blending error. The results of the re-analysis of the 242-A Evaporator`s ammonia release scenario are as follows. The onsite receptor 100 m away from the release point (242-A vessel vent stack) is projected to be exposed to a maximum ground-level concentration of ammonia of 8.3 ppm. The maximally-exposed offsite receptor, located at the nearest Hanford Site boundary 16 km away from the 242-A vessel vent stack, will be exposed to a maximum ground-level concentration of 0.11 ppm ammonia.

  20. 1998 Annual Cathodic Protection Survey Report for the 242-A Evaporator Area

    SciTech Connect

    BOWMAN, T.J.

    1999-12-07

    This report is the second annual cathodic protection report for the 242-A evaporator. The report documents and trends annual polarization survey data, rectifier inspection data, and continuity data from 1994 through mid-1999.

  1. 242-A Evaporator/Liquid Effluent Retention Facility data quality objectives

    SciTech Connect

    Von Bargen, B.H.

    1994-09-29

    The purpose of data quality objectives (DQO) is to determine the most cost effective methods of gathering the essential data necessary to make decisions to support successful operation of the facility. The essential data is defined by such information as sample amount, sample location, required analyses, and how sampling and analyses are performed. Successful operation is defined as meeting the campaign objectives while operating within established requirements. This DQO document addresses that portion of the system from 242-A Evaporator candidate feed tanks through discharge of process condensate to the Liquid Effluent Retention of Facility (LERF). Later revisions will incorporate and integrate the entire system, including the Effluent Treatment Facility (ETF).

  2. Facility effluent monitoring plan for 242-A evaporator facility

    SciTech Connect

    Crummel, G.M.; Gustavson, R.D.

    1995-02-01

    A facility effluent monitoring plan is required by the U.S. Department of Energy in DOE Order 5400.1 for any operations that involve hazardous materials and radioactive substances that could affect employee or public safety or the environment. A facility effluent monitoring plan determination was performed during Calendar Year 1991 and the evaluation showed the need for a facility effluent monitoring plan. This document is prepared using the specific guidelines identified in A Guide for Preparing Hanford Site Facility Effluent Monitoring Plans, WHC-EP-0438-1. This facility effluent monitoring plan assesses effluent monitoring systems and evaluates whether they are adequate to ensure the public health and safety as specified in applicable federal, state, and local requirements. This facility effluent monitoring plan shall ensure long-range integrity of the effluent monitoring systems by requiring an update whenever a new process or operation introduces new hazardous materials or significant radioactive materials. This document must be reviewed annually even if there are no operational changes, and it must be updated, as a minimum, every three years.

  3. High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 2

    SciTech Connect

    Not Available

    1994-04-01

    The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Document (S/RID) is contained in multiple volumes. This document (Volume 2) presents the standards and requirements for the following sections: Quality Assurance, Training and Qualification, Emergency Planning and Preparedness, and Construction.

  4. High level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 6

    SciTech Connect

    Not Available

    1994-04-01

    The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 6) outlines the standards and requirements for the sections on: Environmental Restoration and Waste Management, Research and Development and Experimental Activities, and Nuclear Safety.

  5. High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID)

    SciTech Connect

    Not Available

    1994-04-01

    The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 3) presents the standards and requirements for the following sections: Safeguards and Security, Engineering Design, and Maintenance.

  6. High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 4

    SciTech Connect

    Not Available

    1994-04-01

    The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 4) presents the standards and requirements for the following sections: Radiation Protection and Operations.

  7. High-level waste storage tank farms/242-A evaporator standards/requirements identification document (S/RID), Vol. 4

    SciTech Connect

    Not Available

    1994-04-01

    Radiation protection of personnel and the public is accomplished by establishing a well defined Radiation Protection Organization to ensure that appropriate controls on radioactive materials and radiation sources are implemented and documented. This Requirements Identification Document (RID) applies to the activities, personnel, structures, systems, components, and programs involved in executing the mission of the Tank Farms. The physical boundaries within which the requirements of this RID apply are the Single Shell Tank Farms, Double Shell Tank Farms, 242-A Evaporator-Crystallizer, 242-S, T Evaporators, Liquid Effluent Retention Facility (LERF), Purgewater Storage Facility (PWSF), and all interconnecting piping, valves, instrumentation, and controls. Also included is all piping, valves, instrumentation, and controls up to and including the most remote valve under Tank Farms control at any other Hanford Facility having an interconnection with Tank Farms. The boundary of the structures, systems, components, and programs to which this RID applies, is defined by those that are dedicated to and/or under the control of the Tank Farms Operations Department and are specifically implemented at the Tank Farms.

  8. High-level waste storage tank farms/242-A evaporator Standards/Requirements Identification Document (S/RID), Volume 7. Revision 1

    SciTech Connect

    Burt, D.L.

    1994-04-01

    The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Identification Document (S/RID) is contained in multiple volumes. This document (Volume 7) presents the standards and requirements for the following sections: Occupational Safety and Health, and Environmental Protection.

  9. Configuration management plan for waste tank farms and the 242-A evaporator of tank waste remediation system

    SciTech Connect

    Laney, T.

    1994-08-30

    The configuration management architecture presented in this Configuration Management Plan is based on the functional model established by DOE-STD-1073-93, ``Guide for Operational Configuration Management Program.`` The DOE Standard defines the configuration management program by the five basic program elements of ``program management,`` ``design requirements,`` ``document control,`` ``change control,`` and ``assessments,`` and the two adjunct recovery programs of ``design reconstitution,`` and ``material condition and aging management.`` The CM model of five elements and two adjunct programs strengthen the necessary technical and administrative control to establish and maintain a consistent technical relationship among the requirements, physical configuration, and documentation. Although the DOE Standard was originally developed for the operational phase of nuclear facilities, this plan has the flexibility to be adapted and applied to all life-cycle phases of both nuclear and non-nuclear facilities. The configuration management criteria presented in this plan endorses the DOE Standard and has been tailored specifically to address the technical relationship of requirements, physical configuration, and documentation during the full life cycle of the Waste Tank Farms and 242-A Evaporator of Tank Waste Remediation System.

  10. CAPSULE REPORT: EVAPORATION PROCESS

    EPA Science Inventory

    Evaporation has been an established technology in the metal finishing industry for many years. In this process, wastewaters containing reusable materials, such as copper, nickel, or chromium compounds are heated, producing a water vapor that is continuously removed and condensed....

  11. High-level waste storage tank farms/242-A evaporator standards/requirements identification document (S/RID), Vol. 1

    SciTech Connect

    Not Available

    1994-04-01

    The purpose of this Requirements Identification Document (RID) section is to identify, in one location, all of the facility specific requirements and good industry practices which are necessary or important to establish an effective Issues Management Program for the Tank Farm Facility. The Management Systems Functional Area includes the site management commitment to environmental safety and health (ES&H) policies and controls, to compliance management, to development and management of policy and procedures, to occurrence reporting and corrective actions, resource and issue management, and to the self-assessment process.

  12. Portable brine evaporator unit, process, and system

    DOEpatents

    Hart, Paul John; Miller, Bruce G.; Wincek, Ronald T.; Decker, Glenn E.; Johnson, David K.

    2009-04-07

    The present invention discloses a comprehensive, efficient, and cost effective portable evaporator unit, method, and system for the treatment of brine. The evaporator unit, method, and system require a pretreatment process that removes heavy metals, crude oil, and other contaminates in preparation for the evaporator unit. The pretreatment and the evaporator unit, method, and system process metals and brine at the site where they are generated (the well site). Thus, saving significant money to producers who can avoid present and future increases in transportation costs.

  13. Final characterization and safety screen report of double shell tank 241-AP-104 for 242-A evaporator, campaign 96-1

    SciTech Connect

    Miller, G.L.

    1996-04-19

    This data package satisfies the requirement for a format IV, final report. It is a follow-up to the 45-day safety screen report for tank AP-104. Evaporator candidate feed from tank 241-AP-104 (hereafter referred to as AP-104) was characterized for physical, inorganic, organic and radiochemical parameters by the Westinghouse Hanford Company, 222-S Laboratory, and by the Battelle Pacific Northwest National Laboratory (PNNL), Analytical Chemistry Laboratory (ACL) as directed by the Tank Sample and Analysis Plan (TSAP), References 1 through 4. Preliminary data in the form of summary analytical tables were provided to the project in advance of this final report to enable early estimation of evaporator operational parameters, using the Predict modeling program. Laboratory analyses at ACL Laboratory was performed according to the TSAP. Analyses were performed at the 222-S Laboratory as defined and specified in the TSAP and the Laboratory`s Quality Assurance Plan, References 5 and 6. Any deviations from the instructions documented in the TSAP are discussed in this narrative and are supported with additional documentation. SAMPLING The TSAP, section 2, provided sampling information for waste samples collected from tank AP-104. The bottle-on-a-string method was used to collect liquid grab samples from the tank. Each glass sample bottle was amber, precleaned, and contained approximately 100 milliliters. Each bottle was closed with a teflon seal cap (or teflon septum for volatile organic analysis samples). Field blank samples were prepared by placing deionized water into sampling bottles, lowering the unclosed bottles into the riser for a period of time, retrieving them from the riser, and then closing the bottles with the same types of caps used for the tank samples. None of the samples were preserved by acidification. Upon receipt, the sample bottles destined for organic analyses were placed in a refrigerator. No attempt was made during sampling to assure the complete

  14. Sequence and batch language programs and alarm related C Programs for the 242-A MCS

    SciTech Connect

    Berger, J.F.

    1996-04-15

    A Distributive Process Control system was purchased by Project B-534, 242-A Evaporator/Crystallizer Upgrades. This control system, called the Monitor and Control system (MCS), was installed in the 242-A evaporator located in the 200 East Area. The purpose of the MCS is to monitor and control the Evaporator and monitor a number of alarms and other signals from various Tank Farm facilities. Applications software for the MCS was developed by the Waste Treatment Systems Engineering (WTSE) group of Westinghouse. The standard displays and alarm scheme provide for control and monitoring, but do not directly indicate the signal location or depict the overall process. To do this, WTSE developed a second alarm scheme.

  15. Tubeless evaporation process development: Final report

    SciTech Connect

    Not Available

    1987-12-01

    A tubeless evaporation process which has the potential to combine the advantage of both evaporation and freezing processes, without their disadvantages is being developed. The TEP is capable of concentrating process solutions of such things as sugar, caustic soda, salt, sodium sulfate, black liquor from the pulp and paper industry, cooling tower blowdown, ''spent'' pickling liquor (sulfuric acid) from the steel industry, and nitric acid with potential energy savings of half to three-quarters of the energy required by conventional evaporators, with about half of the capital and maintenance cost. It has similar potential for the production of fresh water from seawater. The process uses working fluids (WF's) at their freezing point to effect direct contact heat exchange. The purpose of this project was to find additional and lower cost WF's in the laboratory, to obtain sizing information for the major equipment for an economic evaluation and a pilot plant design in a bench scale plant, and to perform the economic evaluation, and the pilot plant design and cost estimate. 6 refs., 37 figs., 7 tabs.

  16. Intensification of evaporation processes using surfactants

    NASA Astrophysics Data System (ADS)

    Sharifullin, V. N.; Sharifullin, A. V.

    2015-06-01

    The effect of a group of low molecular surfactants on the evaporation rate during nucleate boiling of water is investigated. It is found that the vaporization rate and heat flux from the heater increase by 4-8% in an electric boiler with surfactants. The analysis of the process based on the model of the phase contact surface restoration made it possible to formulate the mechanism of the effect of considered surfactants.

  17. Dense spray evaporation as a mixing process

    NASA Astrophysics Data System (ADS)

    de Rivas, A.; Villermaux, E.

    2016-05-01

    We explore the processes by which a dense set of small liquid droplets (a spray) evaporates in a dry, stirred gas phase. A dense spray of micron-sized liquid (water or ethanol) droplets is formed in air by a pneumatic atomizer in a closed chamber. The spray is conveyed in ambient air as a plume whose extension depends on the relative humidity of the diluting medium. Standard shear instabilities develop at the plume edge, forming the stretched lamellar structures familiar with passive scalars. Unlike passive scalars however, these lamellae vanish in a finite time, because individual droplets evaporate at their border in contact with the dry environment. Experiments demonstrate that the lifetime of an individual droplet embedded in a lamellae is much larger than expected from the usual d2 law describing the fate of a single drop evaporating in a quiescent environment. By analogy with the way mixing times are understood from the convection-diffusion equation for passive scalars, we show that the lifetime of a spray lamellae stretched at a constant rate γ is tv=1/γ ln(1/+ϕ ϕ ) , where ϕ is a parameter that incorporates the thermodynamic and diffusional properties of the vapor in the diluting phase. The case of time-dependent stretching rates is examined too. A dense spray behaves almost as a (nonconserved) passive scalar.

  18. 242A Distributed Control System Year 2000 Acceptance Test Report

    SciTech Connect

    TEATS, M.C.

    1999-08-31

    This report documents acceptance test results for the 242-A Evaporator distributive control system upgrade to D/3 version 9.0-2 for year 2000 compliance. This report documents the test results obtained by acceptance testing as directed by procedure HNF-2695. This verification procedure will document the initial testing and evaluation of the potential 242-A Distributed Control System (DCS) operating difficulties across the year 2000 boundary and the calendar adjustments needed for the leap year. Baseline system performance data will be recorded using current, as-is operating system software. Data will also be collected for operating system software that has been modified to correct year 2000 problems. This verification procedure is intended to be generic such that it may be performed on any D/3{trademark} (GSE Process Solutions, Inc.) distributed control system that runs with the VMSTM (Digital Equipment Corporation) operating system. This test may be run on simulation or production systems depending upon facility status. On production systems, DCS outages will occur nine times throughout performance of the test. These outages are expected to last about 10 minutes each.

  19. PROCESS WATER BUILDING, TRA605. FLASH EVAPORATOR, CONDENSER (PROJECT FROM EVAPORATOR), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PROCESS WATER BUILDING, TRA-605. FLASH EVAPORATOR, CONDENSER (PROJECT FROM EVAPORATOR), AND STEAM EJECTOR (ALONG REAR WALL). INL NEGATIVE NO. 4377. M.H. Bartz, Photographer, 3/5/1952 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  20. Chemical and biological processes of evaporation ponds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural evaporation ponds are designed to impound and dissipate saline agricultural drainage water in areas with no opportunities for offsite disposal in the San Joaquin Valley of California. This paper reviews and summarizes research findings on the pond chemistry. Drainage waters in these pon...

  1. 32 CFR 242a.3 - Open meetings.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 2 2011-07-01 2011-07-01 false Open meetings. 242a.3 Section 242a.3 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PUBLIC MEETING PROCEDURES OF THE BOARD OF REGENTS, UNIFORMED SERVICES UNIVERSITY OF THE HEALTH SCIENCES § 242a.3 Open meetings. (a) Members shall...

  2. 32 CFR 242a.3 - Open meetings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Open meetings. 242a.3 Section 242a.3 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PUBLIC MEETING PROCEDURES OF THE BOARD OF REGENTS, UNIFORMED SERVICES UNIVERSITY OF THE HEALTH SCIENCES § 242a.3 Open meetings. (a) Members shall...

  3. 32 CFR 242a.8 - Effective date.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Effective date. 242a.8 Section 242a.8 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PUBLIC MEETING PROCEDURES OF THE BOARD OF REGENTS, UNIFORMED SERVICES UNIVERSITY OF THE HEALTH SCIENCES § 242a.8 Effective date. This part...

  4. 32 CFR 242a.1 - Applicability.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Applicability. 242a.1 Section 242a.1 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PUBLIC MEETING PROCEDURES OF THE BOARD OF REGENTS, UNIFORMED SERVICES UNIVERSITY OF THE HEALTH SCIENCES § 242a.1 Applicability. These...

  5. 242-A Campaign 94-1 post run document

    SciTech Connect

    Guthrie, M.D.

    1994-09-30

    The purpose of this post-run document is to summarize the results of 242-A Evaporator Campaign 94-1 as required. Campaign 94-1 represents the first Evaporator operation since 1989, following completion of the B-534 upgrades and Liquid Effluent Retention Facility (LERF) construction. The purpose of Campaign 94-1 was to concentrate dilute waste from TK-102-AW, TK-106-AW, and TK-103-AP. From an available 2.87 million gallon feedstock of dilute waste contained in 102-AW, 106-AW and 103-AP, an overall Waste Volume Reduction (WVR) of 2.39 million gallons (83% WVRF) was achieved. At the completion of the campaign, approximately 477,000 gallons of dilute double-shell slurry feed (DDSSF) was produced with a SpG. of 1.25--1.30. Total process condensate discharged to LERF was 3.09 million gallons, achieving a condensate/WVR ratio of 1.29. Throughput for Campaign 94-1 was 5.27 million gallons. Total steam condensate and cooling water discharge to B-pond was 4.7 and 216 million gallons respectively. The evaporator operated approximately 43 days of the 60 day campaign for a total operating efficiency of 73%. Campaign 94-1 was completed without any discharge limit, Operating Specification Document, or Operational Safety Requirement violations. Major problems encountered during the run included the following: (1) high CA1 deentrainment pad dP`s caused by foaming, (2) condensate pump P-C100 failure, and (3) ion exchange column dP`s and efficiency.

  6. Mechanisms of solvent evaporation encapsulation processes: prediction of solvent evaporation rate.

    PubMed

    Wang, J; Schwendeman, S P

    1999-10-01

    The mechanism of organic solvent evaporation during microencapsulation and its role during microsphere hardening has been investigated. Evaporation and encapsulation studies were carried out in a jacketed beaker, filled with aqueous hardening solution, which was maintained at constant temperature and constant stirring rate in the turbulent regime. Evaporation of dissolved methylene chloride (MC), ethyl acetate (EA), and acetonitrile (ACN) was examined by the decline in organic solvent concentration in the hardening bath, which was monitored by gas chromatography. The evaporation from the bath followed first-order kinetics under dilute conditions (e.g., MC < 3 mg/mL), yielding an overall permeability coefficient, P. The value of P was theoretically related to the Kolmogorov length-scale of turbulence under conditions that favor liquid-side transport control. According to theory, factors that favored liquid-phase control (as opposed to gas-phase control) were those that favored a high Henry's law constant [i.e., elevated temperature near the normal boiling point (bp) of the organic solvent] and properties of the dissolved organic solvent (i.e., low normal bp and low aqueous solubility). These theoretical hypotheses were confirmed by (1) correlating the experimentally determined P with process variables raised to the appropriate power according to theory, r(2) = 0.95 (i.e., P approximately rotational speed, omega(3/4), impeller diameter, d (5/4), volume of hardening bath, V(-1/4), and the product of kinematic viscosity and diffusion coefficient, nu(-5/12)D (2/3)), and (2) illustrating that at constant temperature, the tendency of the evaporation system to obey liquid-side transport control follows the same order of increasing Henry's law constant (i.e., MC > EA > ACN). To establish the relationship of evaporation with microsphere hardening, the decline in MC concentration was determined in both the continuous and dispersed polymer phases during microencapsulation. By

  7. EVAPORATIVE PROCESS FOR TREATMENT OF PHOSPHATE CONTAINING EFFLUENT

    EPA Science Inventory

    A unique evaporation/humidification process for treating wastewater effluent has been developed at Alcoa Laboratories. A major portion of the effluent is recovered as water of high purity suitable for recycle or reuse, and the small volume of concentrated chemicals can be either ...

  8. Sequence and batch language programs and alarm-related ``C`` programs for the 242-A MCS. Revision 2

    SciTech Connect

    Berger, J.F.

    1995-03-01

    A Distributive Process Control system was purchased by Project B-534, ``242-A Evaporator/Crystallizer Upgrades``. This control system, called the Monitor and Control System (MCS), was installed in the 242-A Evaporator located in the 200 East Area. The purpose of the MCS is to monitor and control the Evaporator and monitor a number of alarms and other signals from various Tank Farm facilities. Applications software for the MCS was developed by the Waste Treatment Systems Engineering (WTSE) group of Westinghouse. The standard displays and alarm scheme provide for control and monitoring, but do not directly indicate the signal location or depict the overall process. To do this, WTSE developed a second alarm scheme which uses special programs, annunciator keys, and process graphics. The special programs are written in two languages; Sequence and Batch Language (SABL), and ``C`` language. The WTSE-developed alarm scheme works as described below: SABL relates signals and alarms to the annunciator keys, called SKID keys. When an alarm occurs, a SABL program causes a SKID key to flash, and if the alarm is of yellow or white priority then a ``C`` program turns on an audible horn (the D/3 system uses a different audible horn for the red priority alarms). The horn and flashing key draws the attention of the operator.

  9. Geochemical modeling of evaporation process in Lake Qarun, Egypt

    NASA Astrophysics Data System (ADS)

    Abdel Wahed, Mahmoud S. M.; Mohamed, Essam A.; El-Sayed, Mohamed I.; M'nif, Adel; Sillanpää, Mika

    2014-09-01

    Lake Qarun is an inland closed saline lake. It lies within the Fayoum Depression in the Western Desert of Egypt. Evaporation modeling has been carried out using PHREEQC to simulate the geochemical evolution of surface drainage waters inflow towards lake water. In the case of Lake Qarun, it is the first attempt to carry out such kind of modeling. Performance of this model helped to address the different sources of dissolved major ions to Lake Qarun and to identify the mechanisms control the lake's water chemistry. The model demonstrated that evaporation-crystallization process is the main mechanism controlling the evolution of lake water chemistry where major ions Na+, Mg2+, Cl- and SO42- have been built up in the lake by evaporation while Ca2+ and HCO3- are depleted by calcite precipitation. Moreover, the simulated model reproduced the real data observed in Lake Qarun except in the case of SO42- which is in real more enriched in the lake than the model output. The additional source of SO42- is reported to be from groundwater. The models result agreed well with the modified evolutionary Hardie and Eugster's scheme (1970) in which the final major composition of Lake Qarun water is Na-Mg-SO4-Cl type. In future, the monitoring of Lake Qarun chemistry with detection of any other sources of elements and/or local reactions inside the lake can be detected by performing the simulated evaporation model reported by the present study.

  10. Reactive Evaporation And Plasma Processes For Thin Film Optical Coatings

    NASA Astrophysics Data System (ADS)

    Ebert, Johannes

    1989-02-01

    Bombardment of growing films with reactive particles has developed into a powerful technology over the last 3o years. Compared to normal evaporation methods, important improvements are: better adhesion between film and substrate, high film density, fast coating rate and stoichiometric layers with low optical losses. Although the techniques used to achieve the desired properties vary quite dramatically from high pressure plasma processing to bombardment with monoenergetic ion beams in ultra high vacuum environment, from particles with nearly thermal to some keV energy and from discharge currents of some μA to more than 1oo A in industrial applications, the ion-surface interaction, which causes the modification of the films, is the basic of all reactive deposition processes. The purpose of this paper is to review plasma processes for the production of optical coatings including ion assisted deposition, ion plating and ion cluster beam deposition, comparing the structural and optical properties of the films. Some applications of reactive evaporation presented in the following papers demonstrate the potential use of reactive evaporation and plasma processes for solving optical problems.

  11. Multiparticle versus single sequential emission in nuclear evaporation processes

    NASA Astrophysics Data System (ADS)

    Pinheiro, A. R. C.; De Assis, L. P. G.; Duarte, S. B.; Santos, B. M.; Gonçalves, M.

    2016-03-01

    The role of simultaneous particle emission processes in the evaporation phase is investigated in the high-energy regime of compound nucleus excitation. A Monte Carlo simulation is employed to consider the effect of different emission channels on the particle yield and on the fission process occurrence. A significant change is shown on evaporation-phase results due to the inclusion of multiparticle emission channels in the calculation of the compound nucleus modes of deexcitation. The total yield of neutrons and charged particles suffer an significant change in respect to results obtained in the conventional approach restricted to the sequential one-particle emission mechanism. These particle multiplicities, determined as a function of the excitation energy, present a qualitative change at the high-excitation-energy regime of the compound nucleus. This behavior is confirmed when a different mass formula is used to determine separation and nuclear binding energies. This finding is an important aspect for the study of spallation reaction in acceleration driven system (ADS) reactors, since the majority of neutrons generated in these reactions come from the evaporation stage of the reaction.

  12. Techniques for evaluation of E-beam evaporative processes

    SciTech Connect

    Meier, T.C.; Nelson, C.M.

    1996-10-01

    High dynamic range video imaging of the molten pool surface has provided insight regarding process responses at the melt pool liquid-vapor interface. A water-cooled video camera provides continuous high resolution imaging of the pool surface from a low angle position within 20 cm of the liquid-vapor interface. From the vantage point, the e-beam footprint is clearly defined and melt pool free surface shape can be observed. Effects of changes in a beam footprint, power distribution, and sweep frequency on pool surface shape and stability of vaporization are immediately shown. Other events observed and recorded include: formation of the pool and dissipation of ``rafts`` on the pool surface during startup, behavior of feed material as it enters the pool, effects of feed configuration changes on mixing of feed entering the pool volume and behaviors of co-evaporated materials of different vapor pressures at the feed/pool boundary. When used in conjunction with laser vapor monitoring, correlation between pool surface phenomena and vaporizer performance has been identified. This video capability was used in verifying the titanium evaporation model results presented at this conference by confirming the calculated melt pool surface deformations caused by vapor pressure of the departing evaporant at the liquid-vapor interface.

  13. Fixture for forming evaporative pattern (EPC) process patterns

    DOEpatents

    Turner, Paul C.; Jordan, Ronald R.; Hansen, Jeffrey S.

    1993-01-01

    A method of casting metal using evaporative pattern casting process patterns in combination with a fixture for creating and maintaining a desired configuration in flexible patterns. A pattern is constructed and gently bent to the curvature of a suitable fixture. String or thin wire, which burns off during casting, is used to tie the pattern to the fixture. The fixture with pattern is dipped in a commercially available refractory wash to prevent metal adherence and sticking to the fixture. When the refractory wash is dry, the fixture and pattern are placed in a flask, and sand is added and compacted by vibration. The pattern remains in position, restrained by the fixture. Metal that is poured directly into the pattern replaces the pattern exactly but does not contact or weld to the fixture due to the protective refractory layer. When solid, the casting is easily separated from the fixture. The fixture can be cleaned for reuse in conventional casting cleaning equipment.

  14. Synthesis of nanoporous silicon carbide ceramics by thermal evaporation process

    NASA Astrophysics Data System (ADS)

    Wei, Jian

    2010-09-01

    New nanoporous β-SiC ceramics were synthesized by a simple thermal evaporation method with commercial silicon powder and activated carbon fragments. The results of scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy and X-ray diffraction indicated that the microstructure of the β-SiC nanoporous ceramics was uniform and consistent with the pore size of 50-100 nm. The β-SiC nanocrystal grains of 50-200 nm were accumulated together to form a nanopore network. The formation mechanism was attributed to a template synthesis process, in which activated carbon fragments were employed as the template and they reacted with vaporized silicon through a vapor-solid way.

  15. Evaporant feed device facilitates flash vapor deposition process in vacuum

    NASA Technical Reports Server (NTRS)

    Hermann, W. A.; Stirn, R. J.

    1967-01-01

    Mechanism using a helix sequentially feeds prescribed amounts of metal charges into an evaporation boat used for flash vapor deposition of the evaporants onto a substrate in a vacuum chamber. The helix is advanced by external manual controls extending through sealed feed- through devices into the chamber wall.

  16. Interfacial phenomena and microscale transport processes in evaporating ultrathin menisci

    NASA Astrophysics Data System (ADS)

    Panchamgam, Sashidhar S.

    The study of interfacial phenomena in the three-phase contact line region, where a liquid-vapor interface intersects a solid surface, is of importance to many equilibrium and non-equilibrium processes. However, lack of experimental data on microscale transport processes controlled by interfacial phenomena has restricted progress. This thesis includes a high resolution image analyzing technique, based on reflectivity measurements, that accurately measures the thickness, contact angle and curvature profiles of ultrathin films, drops and curved menisci. In particular, the technique was used to emphasize measurements for thicknesses, delta < 100 nm, while studying delta < 2.5 mum. Using the "reflectivity technique", we studied fluid flow and heat transfer in a wickless, miniature heat pipe, a device which will be a very effective passive heat exchanger in a microgravity environment. The heat pipe is based on the Vertical Constrained Vapor Bubble (VCVB) concept. The broad objective was to increase the efficiency of the miniature heat pipe by enhancing the liquid flow towards the hotter region. This was achieved by understanding and manipulating the wetting and spreading characteristics of the liquid on the solid surface. By using a binary mixture (98% pentane and 2% octane by volume) instead of either pure pentane or octane, we were able to achieve a significant increase in the microscale phase change heat transfer. The experimental work was supported by numerical studies to understand the physics of the system at microscopic scale. In addition, using the reflectivity technique, we enhanced our understanding of interfacial phenomena in the contact line region. Experiments included flow instabilities in HFE-7000 meniscus on quartz (System S1), the spreading of a pentane (System S2 and S3), octane (System S4) and binary mixture menisci (System S5) during evaporation. The main objectives of the work are to present a new experimental technique, new observations, new data

  17. 32 CFR 242a.5 - Procedure for announcing meetings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Procedure for announcing meetings. 242a.5 Section 242a.5 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PUBLIC MEETING PROCEDURES OF THE BOARD OF REGENTS, UNIFORMED SERVICES UNIVERSITY OF THE HEALTH SCIENCES § 242a.5 Procedure...

  18. Transport processes and interfacial phenomena in an evaporating meniscus

    SciTech Connect

    Sujanani, M.; Wayner, P.C. Jr.

    1991-01-01

    When a liquid film wets a solid surface, a contact line region is formed where the vapor, liquid and solid phases are in close proximity. The film thickness in this region varies from about 10 {mu}m (Capillary Meniscus) to less than about 100 nm (Adsorbed film). In addition to being functions of temperature and pressure (as for a bulk phase), the thermodynamic properties (e.g., chemical potential) of these thin films depend on their shape (curvature) and thickness due to surface forces. The coupled transport processes and interfacial phenomena occurring in this microscopic region are also controlled by these surface forces. The objective of this paper is to report experimental data which complement earlier analytical models of this region. The experimental setup consists of a flat silicon plate partially immersed at a small angle, {theta}, in a pool of liquid. The plate is in a closed cell and a spreading liquid (1,1,2-Trichlorotrifluoro ethane), in equilibrium with its own vapor, forms a zero contact angle with the plate. The plate can be electrically heated at the upper end by supplying power to a thin, rectangular platinum heater which is painted on the backside of the silicon wafer. The meniscus thickness profile, which is related to the effective pressure in the liquid, was used as a probe for understanding the sensitivity of the meniscus to the non-equilibrium effects associated with evaporation/condensation mechanisms. 5 refs., 8 figs.

  19. 95-1 Campaign evaporator boildown results

    SciTech Connect

    Miller, G.L.

    1994-10-10

    The Process Chemistry Laboratories were requested to support the 242-A Evaporator restart as part of the overall 222-S laboratory effort. The net purpose of these studies is to determine the characteristics of double-shell tank materials as they are processed in the evaporator. The results for the boildown study (which includes pressure and temperature versus % waste volume reduction and density of final boildown residue) supporting the 242-A Evaporator restart are reported below. The boildown was performed in a vacuum distillation apparatus with an adjustable vacuum limiting manometer and an isolatable collection graduated cylinder. The boildown was conducted over a seven hour period. The evaporation was done at 60 torr (to avoid excessive foaming and bumping of solution) for approximately half of the boildown, the pressure then being reduced to 40 torr when the reduction in solution volume allowed this to be done. Percent waste volume reduction was measured by observing the amount of condensate collected in a graduated cylinder. As the graduated cylinder became full, it was isolated from the rest of the system and the condensate removed. Pressure was set using an electronic manometer with a low pressure limiter set at the desired level. Temperature was measured using a J-type thermocouple. The apparatus was calibrated by observing the pressure versus temperature response of pure water, and comparing the values thus obtained to published values.

  20. Water evaporation particularities in the process of forest fire extinguishing

    NASA Astrophysics Data System (ADS)

    Strizhak, Pavel A.; Volkov, Roman S.; Vysokomornaya, Olga V.; Voytkov, Ivan S.

    2015-01-01

    Numerical simulation of water massif motion through the high temperature gases corresponding to the typical conditions of forest fires was carried out. Maximal values of part by volume of liquid evaporating from water massif under its motion through the flaming burning area were determined when solving the heat and mass transfer problem under the conditions of endothermic phase transformations. Influence of liquid phase transition heat on the heat and mass transfer conditions on the track of water massif was determined. The expediency of polydisperse interspaced in time and space atomization of water massifs under the large-scale (especially, forest fires) fire extinguishing was proved.

  1. PROCESS WATER BUILDING, TRA605. INSIDE A FLASH EVAPORATOR. INL NEGATIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PROCESS WATER BUILDING, TRA-605. INSIDE A FLASH EVAPORATOR. INL NEGATIVE NO. 3323. Unknown Photographer, 9/12/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  2. How are particle production, nucleon emission and target fragment evaporation processes interrelated in hadron-nucleus collisions?

    NASA Technical Reports Server (NTRS)

    Strugalski, Z.

    1985-01-01

    Relations between particle production, nucleon emission, and fragment evaporation processes were searched for in hadron-nucleus collisions. It was stated that: (1) the nucleon emission and target fragment evaporation proceed independently of the particle production process; and (2) relation between multiplicities of the emitted protons and of the evaporated charged fragments is expressed by simple formula.

  3. 32 CFR 242a.6 - Procedure for closing meetings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Procedure for closing meetings. 242a.6 Section... SCIENCES § 242a.6 Procedure for closing meetings. (a) Action to close a meeting or portion thereof... each Board or committee meeting a portion or portions of which are proposed to be closed to the...

  4. 32 CFR 242a.6 - Procedure for closing meetings.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 2 2011-07-01 2011-07-01 false Procedure for closing meetings. 242a.6 Section... SCIENCES § 242a.6 Procedure for closing meetings. (a) Action to close a meeting or portion thereof... each Board or committee meeting a portion or portions of which are proposed to be closed to the...

  5. 32 CFR 242a.6 - Procedure for closing meetings.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 2 2013-07-01 2013-07-01 false Procedure for closing meetings. 242a.6 Section... SCIENCES § 242a.6 Procedure for closing meetings. (a) Action to close a meeting or portion thereof... each Board or committee meeting a portion or portions of which are proposed to be closed to the...

  6. The evaporation of dense sprays as a mixing process

    NASA Astrophysics Data System (ADS)

    de Rivas, Alois; Villermaux, Emmanuel

    2014-11-01

    A dense spray of micron-sized droplets (water or ethanol) is formed in air by a pneumatic atomizer in a closed chamber, and is then conveyed through a nozzle in ambient air, forming a plume whose extension depends on the relative humidity of the diluting medium. We focus on the dry ambient medium, and large plume Reynolds number limit. Standard shear instabilities develop at the plume edge, forming the stretched lamellar structures familiar with passive scalars, except that these vanish in a finite time, because individual droplets evaporate at their border. Experiments also demonstrate that the lifetime of an individual droplet embedded in a lamellae is much larger than expected from the usual d-square law for an isolated droplet. By analogy with the way mixing times are understood from the convection-diffusion equation for passive scalars, we show that the lifetime of a lamellae stretched at a rate γ is tv =1/γ ln (1/+ ϕ ϕ ) where ϕ is a parameter which incorporates the thermodynamic and diffusional properties of the vapor in the diluting phase. The droplets field thus behaves as a -non conserved- passive scalar.

  7. Evaporator fouling tendencies of thin stillage and concentrates from the dry grind process

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the US, more than 200 maize processing plants use multiple effect evaporators to remove water from thin stillage and steepwater during dry grind and wet milling processes, respectively. During the dry grind process, unfermentables are centrifuged and the liquid fraction, thin stillage, is concen...

  8. Evaporation Erosion During the Relay Contact Breaking Process Based on a Simplified Arc Model

    NASA Astrophysics Data System (ADS)

    Cui, Xinglei; Zhou, Xue; Zhai, Guofu; Peng, Xiyuan

    2016-05-01

    Evaporation erosion of the contacts is one of the fundamental failure mechanisms for relays. In this paper, the evaporation erosion characteristics are investigated for the copper contact pair breaking a resistive direct current (dc) 30 V/10 A circuit in the air. Molten pool simulation of the contacts is coupled with the gas dynamics to calculate the evaporation rate. A simplified arc model is constructed to obtain the contact voltage and current variations with time for the prediction of the current density and the heat flux distributions flowing from the arc into the contacts. The evaporation rate and mass variations with time during the breaking process are presented. Experiments are carried out to verify the simulation results. supported by National Natural Science Foundation of China (Nos. 51377038, 51307030)

  9. Laboratory simulation of processes of evaporation, condensation, and sputtering taking place on the surface of the moon

    NASA Technical Reports Server (NTRS)

    Nusinov, M. D.; Kochnev, V. A.; Chernyak, Y. B.; Kuznetsov, A. V.; Kosolapov, A. I.; Yakovlev, O. I.

    1974-01-01

    Study of evaporation, condensation and sputtering on the moon can provide information on the same processes on other planets, and reveal details of the formation of the lunar regolith. Simulation methods include vacuum evaporation, laser evaporation, and bubbling gas through melts.

  10. Spallation process with simultaneous multi-particle emission in nuclear evaporation

    SciTech Connect

    Santos, B. M.

    2013-05-06

    High energy probes have been used currently to explore nuclear reaction mechanism and nuclear structure. The spallation process governs the reaction process around 1 GeV energy regime. A new aspect introduced here to describe the nuclear reaction is the in-medium nucleonnucleon collision framework. The nucleon-nucleon scattering is kinematically treated by using an effective mass to represent the nuclear binding. In respect to the evaporation phase of the reaction, we introduce the simultaneous particles emission decay. This process becomes important due to the rise of new channels at high excitation energy regime of the compound nucleus. As results, the particles yields in the rapid and evaporation phases are obtained and compared to experimental data. The effect and relevance of these simultaneous emission processes in the evaporation chain is also discussed.

  11. A study on the evaporation process with multiple point-sources

    NASA Astrophysics Data System (ADS)

    Jun, Sunghoon; Kim, Minseok; Kim, Suk Han; Lee, Moon Yong; Lee, Eung Ki

    2013-10-01

    In Organic Light Emitting Display (OLED) manufacturing processes, there is a need to enlarge the mother glass substrate to raise its productivity and enable OLED TV. The larger the size of the glass substrate, the more difficult it is to establish a uniform thickness profile of the organic thin-film layer in the vacuum evaporation process. In this paper, a multiple point-source evaporation process is proposed to deposit a uniform organic layer uniformly. Using this method, a uniformity of 3.75% was achieved along a 1,300 mm length of Gen. 5.5 glass substrate (1300 × 1500 mm2).

  12. Optical diagnostics of a single evaporating droplet using fast parallel computing on graphics processing units

    NASA Astrophysics Data System (ADS)

    Jakubczyk, D.; Migacz, S.; Derkachov, G.; Woźniak, M.; Archer, J.; Kolwas, K.

    2016-09-01

    We report on the first application of the graphics processing units (GPUs) accelerated computing technology to improve performance of numerical methods used for the optical characterization of evaporating microdroplets. Single microdroplets of various liquids with different volatility and molecular weight (glycerine, glycols, water, etc.), as well as mixtures of liquids and diverse suspensions evaporate inside the electrodynamic trap under the chosen temperature and composition of atmosphere. The series of scattering patterns recorded from the evaporating microdroplets are processed by fitting complete Mie theory predictions with gradientless lookup table method. We showed that computations on GPUs can be effectively applied to inverse scattering problems. In particular, our technique accelerated calculations of the Mie scattering theory on a single-core processor in a Matlab environment over 800 times and almost 100 times comparing to the corresponding code in C language. Additionally, we overcame problems of the time-consuming data post-processing when some of the parameters (particularly the refractive index) of an investigated liquid are uncertain. Our program allows us to track the parameters characterizing the evaporating droplet nearly simultaneously with the progress of evaporation.

  13. Hanford high-level waste evaporator/crystallizer corrosion evaluation

    SciTech Connect

    Ohl, P.C.; Carlos, W.C.

    1993-10-01

    The US Department of Energy, Hanford Site nuclear reservation, located in Southeastern Washington State, is currently home to 61 Mgal of radioactive waste stored in 177 large underground storage tanks. As an intermediate waste volume reduction, the 242-A Evaporator/Crystallizer processes waste solutions from most of the operating laboratories and plants on the Hanford Site. The waste solutions are concentrated in the Evaporator/Crystallizer to a slurry of liquid and crystallized salts. This concentrated slurry is returned to Hanford Site waste tanks at a significantly reduced volume. The Washington State Department of Ecology Dangerous Waste Regulations, WAC 173-393 require that a tank system integrity assessment be completed and maintained on file at the facility for all dangerous waste tank systems. This corrosion evaluation was performed in support of the 242-A Evaporator/Crystallizer Tank System Integrity Assessment Report. This corrosion evaluation provided a comprehensive compatibility study of the component materials and corrosive environments. Materials used for the Evaporator components and piping include austenitic stainless steels (SS) (primarily ASTM A240, Type 304L) and low alloy carbon steels (CS) (primarily ASTM A53 and A106) with polymeric or asbestos gaskets at flanged connections. Building structure and secondary containment is made from ACI 301-72 Structural Concrete for Buildings and coated with a chemically resistant acrylic coating system.

  14. PROCESS WATER BUILDING, TRA605. FLASH EVAPORATORS ARE PLACED ON UPPER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PROCESS WATER BUILDING, TRA-605. FLASH EVAPORATORS ARE PLACED ON UPPER LEVEL OF EAST SIDE OF BUILDING. WALLS WILL BE FORMED AROUND THEM. WORKING RESERVOIR BEYOND. CAMERA FACING EASTERLY. EXHAUST AIR STACK IS UNDER CONSTRUCTION AT RIGHT OF VIEW. INL NEGATIVE NO. 2579. Unknown Photographer, 6/18/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  15. PROCESS WATER BUILDING, TRA605. ONE OF THREE EVAPORATORS BEFORE IT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PROCESS WATER BUILDING, TRA-605. ONE OF THREE EVAPORATORS BEFORE IT IS INSTALLED IN UPPER LEVEL OF EAST HALF OF BUILDING. INL NEGATIVE NO. 1533. Unknown Photographer, 3/1/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  16. Structural and dynamical heterogeneities in PVA films induced by evaporation during the formation process

    NASA Astrophysics Data System (ADS)

    Ghoshal, Sushanta; Denner, Paul; Stapf, Siegfried; Mattea, Carlos

    2011-10-01

    Microscopic dynamical studies were performed on poly(vinyl alcohol) in aqueous solution by means of NMR microimaging and relaxation techniques. The study indicates a spatial heterogeneity in the molecular dynamics, observed at different heights during evaporation of the solvent. In the advanced stage of the drying process, the microscopic arrangement of the polymer chains during their solidification is influenced by this dynamic heterogeneity and determines the final structure of the film. X-ray diffractometry of the film in its final state confirmed the structural heterogeneity identified by the NMR. This suggests that crystallization of the polymer from the evaporated solution is enhanced on the side of the film where evaporation takes place.

  17. Numerical modelling of evaporation in a ceramic layer in the tape casting process

    NASA Astrophysics Data System (ADS)

    Jabbari, M.; Jambhekar, V. A.; Hattel, J. H.; Helmig, R.

    2016-06-01

    Evaporation of water from a ceramic layer is a key phenomenon in the drying process for the manufacturing of tape cast ceramics. This process contains mass, momentum and energy exchange between the porous medium and the free-flow region. In order to analyze such interaction processes, a Representative Elementary Volume (REV)-scale model concept is presented for coupling non-isothermal multi-phase compositional porous-media flow and single-phase compositional laminar free-flow. The preliminary results show the typical expected evaporation behaviour from a porous medium initially saturated with water, and its transport to the free-flow region according to the existent results from the literature.

  18. Boundary condition effects on polymeric membrane formation: Developing the thermally assisted evaporative phase-separation process

    NASA Astrophysics Data System (ADS)

    Hellman, Diana Joyce

    The evaporative-cast phase-inversion process, also known as the dry-cast process, is one of the standard membrane-formation techniques. This process, typically performed at room temperature, is characterized by a solvent and a nonsolvent evaporating from a ternary polymer solution. The evaporative process is considerably more controllable than other membrane-formation techniques such as the wet-casting process, where the polymer-solvent solution is immersed in a bath of nonsolvent. However, the only way the evaporative-cast process can be completed in a reasonable period of time is for the solvent to have a high vapor pressure at room temperature. To date, this requirement has limited the process to polymers soluble in low-boiling-point solvents. Although the effects of changing the boundary conditions is poorly understood, there are hints in the literature that a systematic study of the effects of the boundary conditions could lead to a method to dry-cast polymers that are soluble only in high-boiling-point solvents. Therefore, the overall goal of this thesis is to investigate the effects of boundary conditions on the evaporative process. This goal was addressed via both experimental and modeling studies. First, the boundary conditions were altered experimentally by elevating the processing temperatures to above room temperature. This led to a novel evaporative process to form membranes from polymers that are soluble only in high-boiling-point solvents, the thermally assisted evaporative phase-separation (TAEPS) process. An extensive experimental study was conducted, investigating the effects of combinations of the different variables including the boundary conditions (air and support temperatures) and the initial conditions (initial solution temperature and composition). The experimental study was performed on a model polymer system (1-octanol/dimethyl formamide (DW)/poly(vinylidene fluoride) (PVDF)) to understand the effects of the variables on the final

  19. A Remote Absorption Process for Disposal of Evaporate and Reverse Osmosis Concentrates

    SciTech Connect

    Brunsell, D.A.

    2008-07-01

    Many commercial nuclear plants and DOE facilities generate secondary waste streams consisting of evaporator bottoms and reverse osmosis (RO) concentrate. Since liquids are not permitted in disposal facilities, these waste streams must be converted to dry solids, either by evaporation to dried solids or by solidification to liquid-free solids. Evaporation of the liquid wastes reduces their volume, but requires costly energy and capital equipment. In some cases, concentration of the contaminants during drying can cause the waste to exceed Class A waste for nuclear utilities or exceed DOE transuranic limits. This means that disposal costs will be increased, or that, when the Barnwell, SC disposal site closes to waste outside of the Atlantic Compact in July 2008, the waste will be precluded from disposal for the foreseeable future). Solidification with cement agents requires less energy and equipment than drying, but results in a volume increase of 50-100%. The doubling or tripling of waste weight, along with the increased volume, sharply increases shipping and disposal costs. Confronted with these unattractive alternatives, Diversified Technologies Services (DTS), in conjunction with selected nuclear utilities and D and D operations at Rocky Flats, undertook an exploratory effort to convert this liquid wastewater to a solid without using cement. This would avoid the bulking effect of cement, and permit the waste to be disposed of the Energy Solutions facility in Utah as well as some DOE facilities. To address the need for an attractive alternative to drying and cement solidification, a test program was developed using a polymer absorbent media to convert the concentrate streams to a liquid-free waste form that meets the waste acceptance criteria of the pertinent burial sites. Two approaches for mixing the polymer with the liquid were tested: mechanical mixing and in-situ incorporation. As part of this test program, a process control program (PCP) was developed that is

  20. Sustained release of risperidone from biodegradable microspheres prepared by in-situ suspension-evaporation process.

    PubMed

    An, Taekun; Choi, Juhyuen; Kim, Aram; Lee, Jin Ho; Nam, Yoonjin; Park, Junsung; Sun, Bo Kyung; Suh, Hearan; Kim, Cherng-Ju; Hwang, Sung-Joo

    2016-04-30

    Risperidone-loaded poly (d,l-lactide-co-glycolide) (PLGA) microspheres were prepared with a suspension-evaporation process with an aqueous suspension containing an in situ-formed aluminum hydroxide inorganic gel (SEP-AL process) and evaluated for encapsulation efficiency, particle size, surface morphology, glass transition temperature, in vitro drug release profile, and in vivo behavior. The SEP-AL microspheres were compared with conventional oil-in-water (O/W) emulsion solvent evaporation method using polyvinylalcohol (PVA) as an emulsifier (CP-PVA process). The microspheres were spherical in shape. DSC measurements showed that risperidone crystallinity was greatly reduced due to the homogeneous distribution of risperidone in PLGA microspheres. In vitro drug release profile from the microspheres showed a sigmoidal pattern of negligible initial burst up to 24h and minimal release (time-lag) for 7days. After the lag phase, slow release took a place up to 25days and then rapid release occurred sharply for 1 week. In vivo rat pharmacokinetic profile from the microspheres showed very low blood concentration level at the initial phase (up to 24h) followed by the latent phase up to 21days. At the 3rd week, main phase started and the blood concentration of the drug increased up to the 5th week, and then gradually decreased. The risperidone-loaded PLGA microspheres produced by SEP-AL process showed excellent controlled release characteristics for the effective treatment of schizophrenia patients. PMID:26899975

  1. Elaboration of ammonio methacrylate copolymer based spongy cationic particles via double emulsion solvent evaporation process.

    PubMed

    Zafar, Nadiah; Bitar, Ahmad; Valour, Jean Pierre; Fessi, Hatem; Elaissari, Abdelhamid

    2016-04-01

    The aim of present work is to investigate systematic study of the preparation of biodegradable particles via double emulsion solvent evaporation technique. The used formation is based on cationic ammonium methacrylate copolymer Eudragit® RS 100, without the use of any stabilizer. The effect of process parameters like ultra turrax® stirring speed and stirring time, ultrasonication time, polymer amount, and volume of outer aqueous phases on the colloidal properties of particles was investigated. All prepared dispersions were characterized in terms of size, size distribution, and electrokinetic properties, and surface morphology was investigated. PMID:26838828

  2. Treatment of a waste oil-in-water emulsion from a copper-rolling process by ultrafiltration and vacuum evaporation.

    PubMed

    Gutiérrez, Gemma; Lobo, Alberto; Benito, José M; Coca, José; Pazos, Carmen

    2011-01-30

    A process is proposed for the treatment of a waste oil-in-water (O/W) emulsion generated in an industrial copper-rolling operation. The use of demulsifier agents improves the subsequent treatment by techniques such as ultrafiltration (UF) or evaporation. The effluent COD is reduced up to 50% when the O/W emulsion is treated by UF using a flat 30 nm TiO(2) ceramic membrane (ΔP = 0.1 MPa) and up to 70% when it is treated by vacuum evaporation, after an emulsion destabilization pretreatment in both cases. Increases in the UF permeate flux and in the evaporation rate are observed when a chemical demulsifier is used in the pretreatment step. A combined process consisting of destabilization/settling, UF, and vacuum evaporation can yield a very high-quality aqueous effluent that could be used for process cooling or emulsion reformulation. PMID:21112152

  3. Visual measurement of the evaporation process of a sessile droplet by dual-channel simultaneous phase-shifting interferometry

    PubMed Central

    Sun, Peng; Zhong, Liyun; Luo, Chunshu; Niu, Wenhu; Lu, Xiaoxu

    2015-01-01

    To perform the visual measurement of the evaporation process of a sessile droplet, a dual-channel simultaneous phase-shifting interferometry (DCSPSI) method is proposed. Based on polarization components to simultaneously generate a pair of orthogonal interferograms with the phase shifts of π/2, the real-time phase of a dynamic process can be retrieved with two-step phase-shifting algorithm. Using this proposed DCSPSI system, the transient mass (TM) of the evaporation process of a sessile droplet with different initial mass were presented through measuring the real-time 3D shape of a droplet. Moreover, the mass flux density (MFD) of the evaporating droplet and its regional distribution were also calculated and analyzed. The experimental results show that the proposed DCSPSI will supply a visual, accurate, noncontact, nondestructive, global tool for the real-time multi-parameter measurement of the droplet evaporation. PMID:26178451

  4. Geochemical Modeling of Evaporation Processes on Mars: Insight From the Sedimentary Record at Meridiani Planum

    NASA Astrophysics Data System (ADS)

    Tosca, N. J.; McLennan, S. M.

    2004-12-01

    The Opportunity rover's analysis of an impure evaporite component present in the Martian sedimentary record reveals a unique geochemical system. The evaporation of basaltic weathering fluids is a process which is rare on Earth, but is likely to have played a major role in the formation of sedimentary rocks at Meridiani Planum. Adequately modeling the evaporation processes in this system must involve adding additional components to current thermodynamic models, namely Fe(II) and Fe(III). The goals of this study are to: (1) develop a thermodynamic database suitable for modeling evaporation of basaltic weathering fluids in the Meridiani system and (2) to apply the model to experimental fluid data obtained in our laboratory from weathering synthetic Martian basalt, which will allow for the testing of hypotheses related to the geochemical evolution of the Meridiani site. The evaporation of these fluids is simulated using an expanded version of the Harvie-Moller-Weare model which employs Pitzer's ion interaction approach in calculating activity coefficients in high ionic strength solutions. This model has been expanded using recent data to include Fe(II) and Fe(III). Although a full set of experimentally-derived data allowing the inclusion of Fe(III) into such models is not yet available, an adequate set of interaction parameters was built, based on viable assumptions and substitutions using analog data (e.g., Al3+, Ga3+, Cr3+). The accuracy of the thermodynamic model in predicting Fe(II) and Fe(III) activities in a multi-component system can be assessed. This is accomplished by comparing calculated Eh values (proportional to aFe2+/aFe3+) to those measured in the field from high ionic strength acid mine waters containing all of the relevant components of the model. The agreement between calculated and observed values suggests that the model calculations are adequate for reaction path calculations. New thermodynamic data for several Fe(II) and/or Fe(III) containing

  5. The third order correction on Hawking radiation and entropy conservation during black hole evaporation process

    NASA Astrophysics Data System (ADS)

    Yan, Hao-Peng; Liu, Wen-Biao

    2016-08-01

    Using Parikh-Wilczek tunneling framework, we calculate the tunneling rate from a Schwarzschild black hole under the third order WKB approximation, and then obtain the expressions for emission spectrum and black hole entropy to the third order correction. The entropy contains four terms including the Bekenstein-Hawking entropy, the logarithmic term, the inverse area term, and the square of inverse area term. In addition, we analyse the correlation between sequential emissions under this approximation. It is shown that the entropy is conserved during the process of black hole evaporation, which consists with the request of quantum mechanics and implies the information is conserved during this process. We also compare the above result with that of pure thermal spectrum case, and find that the non-thermal correction played an important role.

  6. TIPS-DBC small molecule O-FETs fabricated by evaporation and solution processing

    NASA Astrophysics Data System (ADS)

    Gruszecki, Daniel; Singh, Birendra; Bown, Mark; Lewis, David

    2012-02-01

    The performance of organic field effect transistors using the small molecule, tri-isopropyl- silane-di-benzo chrysene (TIPS-DBC) is reported. The field effect mobility μFE is found to depend on the deposition conditions, which affect the morphology of the film. A mobility in the range of 1.5 × 10-6 to 2.4 × 10-4 cm2 V-1 s-1 is obtained from the evaporated films depending on the substrate treatment and deposition temperature, while films deposited by solution-processing techniques yield mobilities in the range of 0.7 × 10-3 to 1.5 × 10-3 cm2 V-1 s-1. The enhanced performance in polycrystalline solution-processed coatings and its relationship to crystallite size is an important parameter in the design of high-performance devices based on small molecules.

  7. Reduction, partial evaporation, and spattering - Possible chemical and physical processes in fluid drop chondrule formation

    NASA Technical Reports Server (NTRS)

    King, E. A.

    1983-01-01

    The major chemical differences between fluid drop chondrules and their probable parent materials may have resulted from the loss of volatiles such as S, H2O, Fe, and volatile siderophile elements by partial evaporation during the chondrule-forming process. Vertical access solar furnace experiments in vacuum and hydrogen have demonstrated such chemical fractionation trends using standard rock samples. The formation of immiscible iron droplets and spherules by in situ reduction of iron from silicate melt and the subsequent evaporation of the iron have been observed directly. During the time that the main sample bead is molten, many small spatter spherules are thrown off the main bead, thereby producing many additional chondrule-like melt spherules that cool rapidly and generate a population of spherules with size frequency distribution characteristics that closely approximate some populations of fluid drop chondrules in chondrites. It is possible that spatter-produced fluid drop chondrules dominate the meteoritic fluid drop chondrule populations. Such meteoritic chondrule populations should be chemically related by various relative amounts of iron and other volatile loss by vapor fractionation.

  8. Sampling and Analysis Plan for Tank 241-AP-108 Waste in Support of Evaporator Campaign 2000-1

    SciTech Connect

    RASMUSSEN, J.H.

    2000-02-28

    This Tank Sampling and Analysis Plan (TSAP) identifies sample collection, laboratory analysis, quality assurance/quality control (QA/QC), and reporting objectives for the characterization of tank 241-AP-108 waste. Technical bases for these objectives are specified in the 242-A Evaporator Data Quality Objectives (Bowman 2000 and Von Bargen 1998) and 108-AP Tank Sampling Requirements in Support of Evaporator Campaign 2000-1 (Le 2000). Evaporator campaign 2000-1 will process waste from tank 241-AP-108 in addition to that from tank 241-AP-107. Characterization results will be used to support the evaporator campaign currently planned for early fiscal year 2000. No other needs (or issues) requiring data for this tank waste apply to this sampling event.

  9. High level waste storage tanks 242-A evaporator standards/requirement identification document

    SciTech Connect

    Biebesheimer, E.

    1996-01-01

    This document, the Standards/Requirements Identification Document (S/RIDS) for the subject facility, represents the necessary and sufficient requirements to provide an adequate level of protection of the worker, public health and safety, and the environment. It lists those source documents from which requirements were extracted, and those requirements documents considered, but from which no requirements where taken. Documents considered as source documents included State and Federal Regulations, DOE Orders, and DOE Standards

  10. High level waste storage tanks 242-A evaporator S/RID phase II assessment report

    SciTech Connect

    Biebesheimer, E.

    1996-09-27

    This document, the Standards/Requirements Identification Document (S/RID) Phase 2 Assessment Report for the subject facility, represents the results of a Performance Assessment to determine whether procedures containing S/RID requirements are fully implemented by field personnel in the field. It contains a summary report and three attachments; an assessment schedule, performance objectives, and assessments for selected functional areas.

  11. Study on icing evolution rule in process of liquid evaporation-freezing by humidity difference

    NASA Astrophysics Data System (ADS)

    Gao, Penghui; Zhang, Donghai; Zhou, Guoqing

    2015-11-01

    Desalination by freezing is of great prospect due to its low energy consumption, little pollution, freedom of corrosion and ease of scaling. A novel freezing desalination method driven by humidity difference between air flow and liquid surface is proposed and verified in this paper. In order to reveal its mechanism, an unsteady-state thermodynamics model was established to simulate icing movement on liquid surface according to heat and mass balance. Effects of humidity difference, airflow velocity and mass diffusion coefficient on icing development were analyzed through theory analysis and experiments. It was found that the larger humidity difference and larger airflow velocity had evident effects on the liquid evaporation-freezing. Meanwhile, fast mass diffusion between mediums was also beneficial to this freezing process.

  12. Experimental investigation of heat transfer in evaporation and condensation processes on capillary surfaces

    NASA Astrophysics Data System (ADS)

    Shekrildze, I. G.; Rusishvili, D. G.

    1980-05-01

    The article describes experimental investigations of the evaporation and condensation of water and ethyl alcohol on wetted threadlike capillary surfaces of materials with different thermal conductivities.

  13. The Development of Young Children's Understanding of the Process of Evaporation.

    ERIC Educational Resources Information Center

    Beveridge, Michael

    1985-01-01

    This investigation of the development of young children's concept of evaporation examines their intuitive explanations of real world events involving evaporation. A study of the effects of providing evidence contradicting their explanations and of directing their attention to relevant situational features provides insight into the development of…

  14. Toxicity assessment of oil field produced water treated by evaporative processes to produce water to irrigation.

    PubMed

    Andrade, V T; Andrade, B G; Costa, B R S; Pereira, O A; Dezotti, M

    2010-01-01

    During the productive life of an oil well, a high quantity of produced water is extracted together with the oil, and it may achieve up to 99% in the end of the well's economical life. Desalination is one of mankind's earliest forms of saline water treatment, and nowadays, it is still a common process used throughout the world. A single-effect mechanical vapor compression (MVC) process was tested. This paper aims to assess the potential toxicity of produced water to be re-used in irrigation. Samples of both produced and distilled water were evaluated by 84 chemical parameters. The distilled produced water presented a reduction up to 97% for the majority of the analyzed parameters, including PAHs. Toxicity bioassays were performed with distilled produced water to evaluate the growth inhibition of Pseudokirchneriella subcapitata algae, the acute toxicity to Danio rerio fish, the germination inhibition of Lactuca sativa vegetable and the severity of toxicity, as well as behavior test with Lumbricid Earthworm Eisenia fetida. The ecotoxicological assays results showed no toxicity, indicating that the referred evaporative process can produce water to be reused in irrigation. PMID:20706017

  15. A theoretical analysis to estimate the hydraulic properties of a loam soil from a capillary-evaporation process

    NASA Astrophysics Data System (ADS)

    Peña-Sancho, Carolina; Ghezzehei, Teamrat A.; Latorre, Borja; Moret-Fernández, David

    2015-04-01

    The determination of the water retention curve (WRC) parameters and the hydraulic conductivity (K) is of paramount importance in many scientific fields such as hydrology or environmental science. Their direct characterization, however, is typically cumbersome and time consuming. This work analyze the viability to estimate the α and n Van Genuchten (VG) WRC parameters and K from following processes: a capillary wetting process at saturation, an evaporation process and a capillary wetting at saturation followed by an evaporation process. The theoretical analysis was carried out on a 5 cm high and 5 cm diameter cylinder filled with loam soil using numerically generated data with the HYDRUS 2D code. The error maps for the above mentioned processes and the n-K, α-n and K-α planes were generated from the RMSE calculated between the original and the simulated cumulative curves. The deviation (%) between the optimal and original hydraulic parameters was also calculated. Results showed that the capillary plus evaporation method applied on the n-K and α-n planes was the unique process that allowed a unique and well defined minimum. For this last case, the deviation for the α and n parameter were 6'67 and 0'88%, respectively. Taking into account that K can be easy measured from the same soil cylinder by means of Darcy's law, we conclude the capillary + evaporation process can be a simple and effective alternative to estimate the WRC parameters. To this end, the hysteresis phenomena due to the wetting-evaporation process should be taking into account.

  16. Soil Evaporation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil evaporation can significantly influence energy flux partitioning of partially vegetated surfaces, ultimately affecting plant transpiration. While important, quantification of soil evaporation, separately from canopy transpiration, is challenging. Techniques for measuring soil evaporation exis...

  17. Evaporation of impact water droplets in interception processes: Historical precedence of the hypothesis and a brief literature overview

    NASA Astrophysics Data System (ADS)

    Dunkerley, David L.

    2009-10-01

    SummaryIntra-storm evaporation depths exceed post-storm evaporation depths in the interception of rainfall on plant canopies. An important fraction of the intra-storm evaporation may involve the small impact (or splash) droplets produced when raindrops, and perhaps gravity drops (drips released from plant parts), collide with wet plant surfaces. This idea has been presented as a new conception by Murakami [Murakami, S., 2006. A proposal for a new forest canopy interception mechanism: splash droplet evaporation. Journal of Hydrology 319, 72-82; Murakami, S., 2007a. Application of three canopy interception models to a young stand of Japanese cypress and interpretation in terms of interception mechanism. Journal of Hydrology 342, 305-319; Murakami, S., 2007b. A follow-up for the splash droplet evaporation hypothesis of canopy interception and remaining problems: why is humidity unsaturated during rainfall? In: Proceedings of the 20th Annual Conference. Japan Society of Hydrology and Water Resources (in Japanese). < http://www.jstage.jst.go.jp/article/jshwr/20/0/20_62/_article>] but was in fact advanced by Dunin [Dunin, F.X., O'Loughlin, E.M., Reyenga, W., 1988. Interception loss from eucalypt forest: lysimeter determination of hourly rates for long term evaluation. Hydrological Processes 2, 315-329] more than 20 years ago. In addition, Dunin et al. considered that canopy ventilation might be enhanced in intense rain. This note draws attention to the historical precedence of the work of Dunin et al. and also presents a short review of literature on impact droplet production, highlighting areas where data are still required for the full exploration of the role of droplet evaporation in canopy interception. Droplet production needs to be properly parameterised and included in models of interception processes and landsurface-atmosphere interactions.

  18. Coffee ring effect resulted conductive nanowire patterns by evaporating colloidal suspension droplets without sintering process

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofeng; Seong, Baekhoon; Yudistira, Hadi Teguh; Byun, Doyoung

    2015-11-01

    Drying colloidal suspensions containing non-volatile solute will form a ring like pattern, which is called ``coffee ring effect.'' Here, we present the coffee ring effect with silver nanowires dispersing into DI water, resulting in a highly dense-packed nanowire ring patterns. The effect of nanowire length, concentration, droplet size, and substrate temperature were investigated. With shorter nanowires, a distinct ring could be obtained. Meanwhile, the concentration of the colloidal suspension was found to affect the ring width. The droplet size and nanowire length played a significant role in affecting the occurrence of the coffee ring effect. When smaller droplets (i.e., less than 150 μm) containing long nanowires (~ 20 μm), the coffee ring effect was suppressed. While smaller droplets containing short nanowires (~ 1 μm), the coffee ring effect was not affected. By increasing the temperature of the substrate, multi-ring pattern was formed inside the original ring. The resistivity of the semi-circle of the nanowire ring was measured, and had a minimum value of 1.32 × 10-6 Ωm without any sintering process. These findings could be exploited to basic study of ring stain effect as well as the practical use, such as evaporative lithography and ink-jet printing for conductive film and display. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (Grant number: 2014-023284).

  19. Group evaporation

    NASA Technical Reports Server (NTRS)

    Shen, Hayley H.

    1991-01-01

    Liquid fuel combustion process is greatly affected by the rate of droplet evaporation. The heat and mass exchanges between gas and liquid couple the dynamics of both phases in all aspects: mass, momentum, and energy. Correct prediction of the evaporation rate is therefore a key issue in engineering design of liquid combustion devices. Current analytical tools for characterizing the behavior of these devices are based on results from a single isolated droplet. Numerous experimental studies have challenged the applicability of these results in a dense spray. To account for the droplets' interaction in a dense spray, a number of theories have been developed in the past decade. Herein, two tasks are examined. One was to study how to implement the existing theoretical results, and the other was to explore the possibility of experimental verifications. The current theoretical results of group evaporation are given for a monodispersed cluster subject to adiabatic conditions. The time evolution of the fluid mechanic and thermodynamic behavior in this cluster is derived. The results given are not in the form of a subscale model for CFD codes.

  20. Numerical simulations of evaporation and condensation processes of giant molecular clouds in a hot plasma

    NASA Astrophysics Data System (ADS)

    Vieser, Wolfgang; Hensler, Gerhard

    We are performing 2D hydrodynamic simulations to examine the evaporation and condensation processes of giant molecular clouds in the hot phase of the interstellar medium (ISM). The evolution of cold and dense clouds (T=1000K, n_H=3{cm}^{-3}, M=6\\cdot10^4 {M}_{\\odot}) is calculated in the subsonic streaming of a hot rarefied plasma (T=5\\cdot10^6K, n_H=6\\cdot10^{-4}{cm}^{-3}). Our code includes self-gravity, heating and cooling effects and heat conduction by electrons. We are using the thermal conductivity of a fully ionized hydrogen plasma (\\propto {T}^{5/2}, Spitzer, 1962, Physics of Fully Ionized Gases) and a saturated heat flux (Cowie & McKee, 1977, ApJ 211, 135) in regions where the mean free path of the electrons is long compared to the temperature scale height. Significant differences occur between simulations with and without heat conduction. In the simulations without heat conduction, the cloud edge is stired up by Kelvin-Helmholtz (K-H) instabilities after only a few dynamical times. It is not possible to incorporate a significant amount of hot gas in the cloud core before the cloud is destroyed by instabilities. The simulations including heat conduction show an evolution that proceeds not as violent as the case without heat conduction. The edge of the cloud remains nearly unsusceptible to K-H instabilities. In this scenario it is possible to mix the formerly hot streaming gas very effectively with the cloud material.

  1. Inkjet Printing of Colloidal Nanospheres: Engineering the Evaporation-Driven Self-Assembly Process to Form Defined Layer Morphologies

    NASA Astrophysics Data System (ADS)

    Sowade, Enrico; Blaudeck, Thomas; Baumann, Reinhard R.

    2015-09-01

    We report on inkjet printing of aqueous colloidal suspensions containing monodisperse silica and/or polystyrene nanosphere particles and a systematic study of the morphology of the deposits as a function of different parameters during inkjet printing and solvent evaporation. The colloidal suspensions act as a model ink for an understanding of layer formation processes and resulting morphologies in inkjet printing in general. We investigated the influence of the surface energy and the temperature of the substrate, the formulation of the suspensions, and the multi-pass printing aiming for layer stacks on the morphology of the deposits. We explain our findings with models of evaporation-driven self-assembly of the nanosphere particles in a liquid droplet and derive methods to direct the self-assembly processes into distinct one- and two-dimensional deposit morphologies.

  2. Pulsed-Neutron-Gamma (PNG) saturation monitoring at the Ketzin pilot site considering displacement and evaporation/precipitation processes

    NASA Astrophysics Data System (ADS)

    Baumann, Gunther; Henninges, Jan

    2013-04-01

    The storage of carbon dioxide (CO2) in saline aquifers is a promising option to reduce emissions of greenhouse gases to the atmosphere and to mitigate global climate change. During the proposed CO2 injection process, application of suitable techniques for monitoring of the induced changes in the subsurface is required. Existing models for the spreading of the CO2, as well as mixing of the different fluids associated with saturation changes or resulting issues from mutual solubility between brine and CO2, need to be checked. For well logging in cased boreholes, which would be the standard situation encountered under the given conditions, only a limited number of techniques like pulsed neutron-gamma (PNG) logging are applicable. The PNG technique uses controlled neutron bursts, which interact with the nuclei of the surrounding borehole and formation. Due to the collision with these neutrons, atoms from the surrounding environment emit gamma rays. The main PNG derived parameter is the capture cross section (Σ) which is derived from the decline of gamma rays with time from neutron capture processes. The high Σ contrast between brine and CO2 results in a high sensitivity to evaluate saturation changes. This makes PNG monitoring favourable for saturation profiling especially in time-lapse mode. Previously, the conventional PNG saturation model based on a displacement process has been used for PNG interpretation in different CO2 storage projects in saline aquifers. But in addition to the displacement process, the mutual solubility between brine and CO2 adds further complex processes like evaporation and salt precipitation, which are not considered in PNG saturation models. These evaporation and precipitation processes are relevant in the vicinity of an injection well, where dry CO2 enters the reservoir. The Σ brine value depends strongly on the brine salinity e.g. its chlorine content which makes PNG measurements suitable for evaporation and salt precipitation

  3. Environmentally benign etching process of amorphous silicon and tungsten using species evaporated from polytetrafluoroethylene and fluorinated ethylene propylene

    NASA Astrophysics Data System (ADS)

    Fujita, Kazushi; Hori, Masaru; Goto, Toshio; Ito, Masafumi

    2003-01-01

    Environmentally benign etching process of amorphous silicon (a-Si) and tungsten (W) by using a plasma process with an evaporation of solid materials system has been developed for replacing a conventional plasma process using green house gases, such as SF6 gas and perfluorocompound gases causing global warming. The evaporation system was designed to generate fluorocarbon species from solid materials by a CO2 laser irradiation. An electron cyclotron resonance (ECR) plasma using O2 accompanied with injection of species evaporated from solid materials has been applied to a-Si and W etching for cleaning process in chemical vapor deposition chamber. Fluorinated ethylene propylene (FEP) and polytetrafluoroethylene (PTFE) are selected as the solid material and the etching characteristics between FEP and PTFE have been compared. Furthermore, the etching of a-Si and W films has been performed in the divergent magnetic field ECR downstream plasma [electron density (ne); ~1010 cm-3, electron temperature (Te); 1.5-2.8 eV] and a planar ECR plasma [ne ~1010 cm-3, Te 3.4-4.4 eV] using O2 gas with FEP evaporation. As a result, high etching rates of a-Si and W films of above 100 nm/min were successfully obtained at a substrate temperature of 400 °C in the planar ECR plasma of higher electron temperature. CFx (x=1-3) radical densities and F atom density in plasmas were measured by an infrared diode laser absorption spectroscopy and an actinometric optical emission spectroscopy, respectively. On the basis of these measurements of species, the etching mechanisms of a-Si and W films are discussed.

  4. Effect of Water Spray Evaporative Cooling at the Inlet of Regeneration Air Stream on the Performance of an Adsorption Desiccant Cooling Process

    NASA Astrophysics Data System (ADS)

    Ando, Kosuke; Kodama, Akio; Hirose, Tsutomu; Goto, Motonobu; Okano, Hiroshi

    This paper shows an influence of evaporative cooler at the inlet of regeneration air stream of an adsorptive desiccant cooling process on the cooling/dehumidifying performance. This evaporative cooling was expected to cause humidity increase in regeneration air reducing the dehumidifying performance of the honeycomb absorber, while the evaporative cooling plays an important role to produce a lower temperature in supply air. Two different airs to be used for the regeneration of the desiccant wheel were considered. One was fresh outside air (OA mode) and the other was air ventilated from the room (RA mode). Experimental results showed that the amount of dehumidified water obtained at the process without water spray evaporative cooler was actually larger than that of process with water spray evaporative cooler. This behavior was mainly due to increase of humidity or relative humidity in the regeneration air as expected. However, temperature of supply air produced by the process with the evaporator was rather lower than that of the other because of the cooled return air, resulting higher CE value. Regarding the operating mode, the evaporative cooler at the OA-mode was no longer useful at higher ambient humidity because of the difficulty of the evaporation of the water in such high humidity. It was also found that its dehumidifying performance was remarkably decreased at higher ambient humidity and lower regeneration temperature since the effective adsorption capacity at the resulting high relative humidity of the regeneration air decreased.

  5. An experimental investigation of OCOTEC direct-contact condensation and evaporation processes

    SciTech Connect

    Sam, R.G.; Patel, B.R.

    1984-02-01

    Heat transfer data are presented for direct-contact evaporator and condenser geometries suitable for Open-Cycle Ocean Thermal Energy Conversion (OCOTEC) applications. Falling turbulent jets and films were tested at typical operating conditions. The flash evaporator performance was relatively constant over the range of conditions tested, with efficiencies as high as 95 percent due to the breakup of the jets (or films) into sprays. The condenser performance was only affected by the jet or film Reynolds number and the steam air content. Condenser heat transfer coefficients of the order of 27 kW/m/sup 20/C were achieved with jets which were higher than those obtained with films. An empirical correlation was developed for the condenser data after it was shown that none of the existing correlations found in the literature could correlate all of the data trends observed.

  6. Waste Heat Recovery and Recycling in Thermal Separation Processes: Distillation, Multi-Effect Evaporation (MEE) and Crystallization Processes

    SciTech Connect

    Emmanuel A. Dada; Chandrakant B. Panchal; Luke K. Achenie; Aaron Reichl; Chris C. Thomas

    2012-12-03

    Evaporation and crystallization are key thermal separation processes for concentrating and purifying inorganic and organic products with energy consumption over 1,000 trillion Btu/yr. This project focused on a challenging task of recovering low-temperature latent heat that can have a paradigm shift in the way thermal process units will be designed and operated to achieve high-energy efficiency and significantly reduce the carbon footprint as well as water footprint. Moreover, this project has evaluated the technical merits of waste-heat powered thermal heat pumps for recovery of latent heat from distillation, multi-effect evaporation (MEE), and crystallization processes and recycling into the process. The Project Team has estimated the potential energy, economics and environmental benefits with the focus on reduction in CO2 emissions that can be realized by 2020, assuming successful development and commercialization of the technology being developed. Specifically, with aggressive industry-wide applications of heat recovery and recycling with absorption heat pumps, energy savings of about 26.7 trillion Btu/yr have been estimated for distillation process. The direct environmental benefits of this project are the reduced emissions of combustible products. The estimated major reduction in environmental pollutants in the distillation processes is in CO2 emission equivalent to 3.5 billion lbs/year. Energy consumption associated with water supply and treatments can vary between 1,900 kWh and 23,700 kWh per million-gallon water depending on sources of natural waters [US DOE, 2006]. Successful implementation of this technology would significantly reduce the demand for cooling-tower waters, and thereby the use and discharge of water treatment chemicals. The Project Team has also identified and characterized working fluid pairs for the moderate-temperature heat pump. For an MEE process, the two promising fluids are LiNO3+KNO3+NANO3 (53:28:19 ) and LiNO3+KNO3+NANO2

  7. Effects of the surroundings and conformerisation of n-dodecane molecules on evaporation/condensation processes

    SciTech Connect

    Gun’ko, Vladimir M.; Nasiri, Rasoul; Sazhin, Sergei S.

    2015-01-21

    The evaporation/condensation coefficient (β) and the evaporation rate (γ) for n-dodecane vs. temperature, gas pressure, gas and liquid density, and solvation effects at a droplet surface are analysed using quantum chemical density functional theory calculations of several ensembles of conformers of n-dodecane molecules in the gas phase (hybrid functional ωB97X-D with the cc-pVTZ and cc-pVDZ basis sets) and in liquid phase (solvation method: SMD/ωB97X-D). It is shown that β depends more strongly on a number of neighbouring molecules interacting with an evaporating molecule at a droplet surface (this number is estimated through changes in the surface Gibbs free energy of solvation) than on pressure in the gas phase or conformerisation and cross-conformerisation of molecules in both phases. Thus, temperature and the surrounding effects at droplet surfaces are the dominant factors affecting the values of β for n-dodecane molecules. These values are shown to be similar (at reduced temperatures T/T{sub c} < 0.8) or slightly larger (at T/T{sub c} > 0.8) than the values of β calculated by the molecular dynamics force fields (MD FF) methods. This endorses the reliability of the previously developed classical approach to estimation of β by the MD FF methods, except at temperatures close to the critical temperature.

  8. Effects of the surroundings and conformerisation of n-dodecane molecules on evaporation/condensation processes.

    PubMed

    Gun'ko, Vladimir M; Nasiri, Rasoul; Sazhin, Sergei S

    2015-01-21

    The evaporation/condensation coefficient (β) and the evaporation rate (γ) for n-dodecane vs. temperature, gas pressure, gas and liquid density, and solvation effects at a droplet surface are analysed using quantum chemical density functional theory calculations of several ensembles of conformers of n-dodecane molecules in the gas phase (hybrid functional ωB97X-D with the cc-pVTZ and cc-pVDZ basis sets) and in liquid phase (solvation method: SMD/ωB97X-D). It is shown that β depends more strongly on a number of neighbouring molecules interacting with an evaporating molecule at a droplet surface (this number is estimated through changes in the surface Gibbs free energy of solvation) than on pressure in the gas phase or conformerisation and cross-conformerisation of molecules in both phases. Thus, temperature and the surrounding effects at droplet surfaces are the dominant factors affecting the values of β for n-dodecane molecules. These values are shown to be similar (at reduced temperatures T/Tc < 0.8) or slightly larger (at T/Tc > 0.8) than the values of β calculated by the molecular dynamics force fields (MD FF) methods. This endorses the reliability of the previously developed classical approach to estimation of β by the MD FF methods, except at temperatures close to the critical temperature. PMID:25612715

  9. Metal patterning using maskless vacuum evaporation process based on selective deposition of photochromic diarylethene

    SciTech Connect

    Takagi, Rie; Masui, Kyoko; Tsujioka, Tsuyoshi; Nakamura, Shinichiro

    2008-11-24

    We developed an electrode/wiring patterning method that does not employ evaporation shadow masks; this method is based on selective metal deposition of photochromic diarylethene (DAE). In the selective Mg deposition based on the photoisomerization of DAE, Mg vapor atoms are deposited only on colored DAE film obtained upon UV irradiation, but not on uncolored film. We demonstrated fine metal Mg patterning with a minimum width of 3 {mu}m and the preparation of a patterned cathode. The selective metal deposition method has significant potential for preparing fine electrodes/wiring for various organic electronic devices.

  10. 32 CFR 242a.7 - Transcripts, recordings, and minutes of closed meetings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SERVICES UNIVERSITY OF THE HEALTH SCIENCES § 242a.7 Transcripts, recordings, and minutes of closed meetings... be available at the actual cost of duplication or transcription. (3) The determination of...

  11. Delta(18)O characteristics of lichens and their effects on evaporative processes of the subjacent soil.

    PubMed

    Hartard, Britta; Máguas, C; Lakatos, M

    2008-03-01

    The study presents first data on the delta(18)O performance of poikilohydrous lichen ground cover, and its potential impact on the isotopic composition of water fluxes arising from subjacent soil layers. As a model organism, the globally distributed lichen Cladina arbuscula was studied under laboratory conditions as well as in the field. During a desiccation experiment, delta(18)O of the lichen's thallus water and of its respired CO(2) became enriched by approximately 7 per thousand and followed a similar enrichment pattern to that expected from homoiohydrous, vascular plants. However, the observed degree of enrichment was lower in comparison to vascular plants due to (i) the lichen's inherent lower evaporative resistances; and (ii) a stronger effect of the more depleted surrounding water vapour. In lichens growing in their natural habitat, this specific pattern may show substantial variations depending on prevailing microclimatic conditions. Within a field study, thallus water delta(18)O of lichens principally proved to become more depleted when close to equilibration with the surroundings. It thereby strongly depended on the absorption of surrounding water vapour. Moreover, the results indicate that lichen mats substantially reduce evaporation rates arising from subjacent soil layers, and may alter the isotopic signal of vapour diffusing away from these layers into more depleted values. PMID:18320432

  12. Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Final report, August 1992--August 1996

    SciTech Connect

    Boysen, J.E.; Walker, K.L.; Mefford, J.L.; Kirsch, J.R.; Harju, J.A.

    1996-06-01

    The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions where subfreezing temperatures seasonally occur. The climates typical of Colorado`s San Juan Basin and eastern slope, as well as the oil and gas producing regions of Wyoming, are well suited for application of these processes in combination. Specifically, the objectives of this research are related to the development of a commercially-economic FTE (freeze-thaw/evaporation) process for the treatment and purification of water produced in conjunction with oil and natural gas. The research required for development of this process consists of three tasks: (1) a literature survey and process modeling and economic analysis; (2) laboratory-scale process evaluation; and (3) field demonstration of the process. Results of research conducted for the completion of these three tasks indicate that produced water treatment and disposal costs for commercial application of the process, would be in the range of $0.20 to $0.30/bbl in the Rocky Mountain region. FTE field demonstration results from northwestern New Mexico during the winter of 1995--96 indicate significant and simultaneous removal of salts, metals, and organics from produced water. Despite the unusually warm winter, process yields demonstrate disposal volume reductions on the order of 80% and confirm the potential for economic production of water suitable for various beneficial uses. The total dissolved solids concentrations of the FTE demonstration streams were 11,600 mg/L (feed), 56,900 mg/L (brine), and 940 mg/L (ice melt).

  13. MOVES2014: Evaporative Emissions Report

    EPA Science Inventory

    Vehicle evaporative emissions are now modeled in EPA’s MOVES according to physical processes, permeation, tank vapor venting, liquid leaks, and refueling emissions. With this update, the following improvements are being incorporated into MOVES evaporative emissions methodology, a...

  14. RESULTS OF GROUNDWATER MONITORING FOR THE 183-H SOLAR EVAPORATION BASINS AND 300 AREA PROCESS TRENCHES JANUARY-JUNE 2010

    SciTech Connect

    WEEKES, D. C.

    2010-11-07

    This is one of a series of reports on Resource Conservation and Recovery Act of 1976 monitoring at the 183-H Solar Evaporation Basins and the 300 Area Process Trenches. It fulfills the requirement of Washington Administrative Code (WAC) 173-303-645(11) to report twice each year on the effectiveness of the corrective action program. This report covers the period from January through June 2010. The concentrations of 183-H Solar Evaporation Basins contaminants remained below applicable concentration limits during the reporting period. The most recent exceedance of a concentration limit was May 2007. The overall concentration of uranium in 300 Area Process Trenches wells remained above the 20 {micro}g/L concentration limit in the three downgradient wells screened at the water table. Fluctuations of uranium concentration are caused by changes in river stage. The concentration of cis-l ,2-dichloroethene remained above the 70 {micro}g/L concentration limit in one deep well (399-1-16B). Concentrations are relatively steady at this well and are not affected by river stage. Trichloroethene concentrations were below detection limits in all wells during the reporting period.

  15. Processing of functional polymers and organic thin films by the matrix-assisted pulsed laser evaporation (MAPLE) technique

    NASA Astrophysics Data System (ADS)

    Piqué, A.; Wu, P.; Ringeisen, B. R.; Bubb, D. M.; Melinger, J. S.; McGill, R. A.; Chrisey, D. B.

    2002-01-01

    The matrix-assisted pulsed laser evaporation (MAPLE) technique has been successfully used to deposit highly uniform thin films of various functional materials such as non-linear optical (NLO) organic materials, conductive polymers, luminescent organic molecules and several types of proteinaceous compounds. MAPLE is a laser evaporation technique for growing thin films of organic and polymeric materials which involves directing a pulsed laser beam (λ=193 nm; fluence=0.01-0.5 J cm -2) onto a frozen target (-40 to -160 °C) consisting of a solute polymeric or organic compound dissolved in a solvent matrix. Using MAPLE, thin films of N-(4-nitrophenyl)-( L)-prolinol or NPP, an NLO material; polypyrrole, a conductive polymer; and tris-(8-hydroxyquinoline) aluminum or Alq3, a luminescent organic compound, have been separately deposited with minor (in the case of Alq3) or no degradation (for the NPP and polypyrrole) to their optical and electrical properties. The MAPLE process has also been used to deposit discrete thin film micro-arrays of biotinylated bovine serum albumin (BSA). The deposited BSA films, after washing with a blocking protein and fluorescently tagged streptavidin, fluoresce when exposed to UV. This fluorescence indicates that the biochemical specificity of the transferred biotinylated protein is unaffected by the MAPLE process. These results demonstrate that the MAPLE technique can be used for growing thin films of functional polymer and active biomaterials.

  16. Streamer Evaporation

    NASA Technical Reports Server (NTRS)

    Suess, Steven T.; Wang, A. H.; Wu, Shi T.; Nerney, S.

    1998-01-01

    Evaporation is the consequence of slow plasma heating near the tops of streamers where the plasma is only weakly contained by the magnetic field. The form it takes is the slow opening of field lines at the top of the streamer and transient formation of new solar wind. It was discovered in polytropic model calculations, where due to the absence of other energy loss mechanisms in magnetostatic streamers, its ultimate endpoint is the complete evaporation of the streamer. This takes, for plausible heating rates, weeks to months in these models. Of course streamers do not behave this way, for more than one reason. One is that there are losses due to thermal conduction to the base of the streamer and radiation from the transition region. Another is that streamer heating must have a characteristic time constant and depend on the ambient physical conditions. We use our global Magnetohydrodynamics (MHD) model with thermal conduction to examine a few examples of the effect of changing the heating scale height and of making ad hoc choices for how the heating depends on ambient conditions. At the same time, we apply and extend the analytic model of streamers, which showed that streamers will be unable to contain plasma for temperatures near the cusp greater than about 2xl0(exp 6) K. Slow solar wind is observed to come from streamers through transient releases. A scenario for this that is consistent with the above physical process is that heating increases the near-cusp temperature until field lines there are forced open. The subsequent evacuation of the flux tubes by the newly forming slow wind decreases the temperature and heating until the flux tubes are able to reclose. Then, over a longer time scale, heating begins to again refill the flux tubes with plasma and increase the temperature until the cycle repeats itself. The calculations we report here are first steps towards quantitative evaluation of this scenario.

  17. Effect of preparation temperature in solvent evaporation process on Eudragit RS microsphere properties.

    PubMed

    Mateović-Rojnik, Tatjana; Frlan, Rok; Bogataj, Marija; Bukovec, Peter; Mrhar, Ales

    2005-01-01

    Eudragit RS 100 microspheres containing ketoprofen as a model drug were prepared by the solvent evaporation method using an acetone/liquid paraffin solvent system. The influence of various preparation temperatures: 10, 25, 35, and 40 degrees C, on particle size and morphology, drug content and release kinetics, and drug crystal state was evaluated. With increasing temperature, microsphere average size was found to increase and particle size distribution to widen significantly. At 10 degrees C particles of irregular shape are formed, whereas higher temperatures gradually improve the sphericity of microspheres. As can be seen from SEM photographs, particle surface roughness decreases as preparation temperature increases. It was found that temperature had no effect either on ketoprofen microencapsulation efficiency or on its crystal state, but it does influence emulsion-stabilizer incorporation. Ketoprofen forms solid solution in Eudragit matrix and maintains amorphous state for significant period of time. Drug release rates from microspheres correlated with microspheres' surface roughness and to a lesser extent with particle size. PMID:15635253

  18. Sequentially evaporated thin Y-Ba-Cu-O superconductor films: Composition and processing effects

    NASA Technical Reports Server (NTRS)

    Valco, George J.; Rohrer, Norman J.; Warner, Joseph D.; Bhasin, Kul B.

    1988-01-01

    Thin films of YBa2Cu3O(7-beta) have been grown by sequential evaporation of Cu, Y, and BaF2 on SrTiO3 and MgO substrates. The onset temperatures were as high as 93 K while T sub c was 85 K. The Ba/Y ratio was varied from 1.9 to 4.0. The Cu/Y ratio was varied from 2.8 to 3.4. The films were then annealed at various times and temperatures. The times ranged from 15 min to 3 hr, while the annealing temperatures used ranged from 850 C to 900 C. A good correlation was found between transition temperature (T sub c) and the annealing conditions; the films annealed at 900 C on SrTiO3 had the best T sub c's. There was a weaker correlation between composition and T sub c. Barium poor films exhibitied semiconducting normal state resistance behavior while barium rich films were metallic. The films were analyzed by resistance versus temperature measurements and scanning electron microscopy. The analysis of the films and the correlations are reported.

  19. Ultra-High Performance, High-Temperature Superconducting Wires via Cost-effective, Scalable, Co-evaporation Process

    SciTech Connect

    Kim, Dr. Hosup; Oh, Sang-Soo; Ha, HS; Youm, D; Moon, SH; Kim, JH; Heo, YU; Dou, SX; Wee, Sung Hun; Goyal, Amit

    2014-01-01

    Long-length, high-temperature superconducting (HTS) wires capable of carrying high critical current, Ic, are required for a wide range of applications. Here, we report extremely high performance HTS wires based on 5 m thick SmBa2Cu3O7- (SmBCO) single layer films on textured metallic templates. SmBCO layer wires over 20 meters long were deposited by a cost-effective, scalable co-evaporation process using a batch-type drum in a dual chamber. All deposition parameters influencing the composition, phase, and texture of the films were optimized via a unique combinatorial method that is broadly applicable for co-evaporation of other promising complex materials containing several cations. Thick SmBCO layers deposited under optimized conditions exhibit excellent cube-on-cube epitaxy. Such excellent structural epitaxy over the entire thickness results in exceptionally high Ic performance, with average Ic over 1000 A/cm for the entire 22 meter long wire and maximum Ic over 1,500 A/cm for a short 12 cm long tape. The Ic values reported in this work are the highest values ever reported from any lengths of cuprate-based HTS wire or conductor.

  20. Indium tin oxide nanowires grown by one-step thermal evaporation-deposition process at low temperature.

    PubMed

    Dong, Haibo; Zhang, Xiaoxian; Niu, Zhiqiang; Zhao, Duan; Li, Jinzhu; Cai, Le; Zhou, Weiya; Xie, Sishen

    2013-02-01

    Indium tin oxide (ITO), as one of the most important transparent conducting oxide, is widely used in electro-optical field. We have developed a simple one-step method to synthesize ITO nanowires at low temperature of 600 degrees C. In detail, mixtures of InN nanowires and SnO powder, with the molar ratio of 10:1, have been used as precursors for the thermal evaporation-deposition of ITO nanowires on silicon/quartz slices. During the growth process, the evaporation temperature is maintained at 600 degrees C, which favors the decomposition of InN and oxidation of In, with a limited incorporation of Sn in the resulting compound (In:Sn approximately 11:1 in atomic ratio). As far as we know, this is the lowest growth temperature reported on the thermal deposition of ITO nanowires. The diameters of the nanowires are about 120 nm and the lengths are up to tens of micrometers. XRD characterization indicates the high crystallization of the nanowires. HRTEM results show the nanowires grow along the [200] direction. The transmittance of the nanowire film on quartz slice is more than 75% in the visible region. Based on photolithography and lift-off techniques, four-terminal measurement was utilized to test the resistivity of individual nanowire (6.11 x 10(-4) omega x cm). The high crystallization quality, good transmittance and low resistivity make as-grown ITO nanowires a promising candidate as transparent electrodes of nanoscale devices. PMID:23646624

  1. Ultra-High Performance, High-Temperature Superconducting Wires via Cost-effective, Scalable, Co-evaporation Process

    PubMed Central

    Kim, Ho-Sup; Oh, Sang-Soo; Ha, Hong-Soo; Youm, Dojun; Moon, Seung-Hyun; Kim, Jung Ho; Dou, Shi Xue; Heo, Yoon-Uk; Wee, Sung-Hun; Goyal, Amit

    2014-01-01

    Long-length, high-temperature superconducting (HTS) wires capable of carrying high critical current, Ic, are required for a wide range of applications. Here, we report extremely high performance HTS wires based on 5 μm thick SmBa2Cu3O7 − δ (SmBCO) single layer films on textured metallic templates. SmBCO layer wires over 20 meters long were deposited by a cost-effective, scalable co-evaporation process using a batch-type drum in a dual chamber. All deposition parameters influencing the composition, phase, and texture of the films were optimized via a unique combinatorial method that is broadly applicable for co-evaporation of other promising complex materials containing several cations. Thick SmBCO layers deposited under optimized conditions exhibit excellent cube-on-cube epitaxy. Such excellent structural epitaxy over the entire thickness results in exceptionally high Ic performance, with average Ic over 1,000 A/cm-width for the entire 22 meter long wire and maximum Ic over 1,500 A/cm-width for a short 12 cm long tape. The Ic values reported in this work are the highest values ever reported from any lengths of cuprate-based HTS wire or conductor. PMID:24752189

  2. Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Quarterly technical progress report, January 1, 1995--March 31, 1995

    SciTech Connect

    Boysen, J.; Morotti, J.

    1995-04-01

    The objectives of this project are related to the development of a commercially-economic natural freeze-thaw/evaporation process for the treatment and purification of water produced in conjunction with oil and gas. Progress is reported on laboratory scale process evaluation and field demonstration of the process.

  3. Synthesis of Novel Double-Layer Nanostructures of SiC–WOxby a Two Step Thermal Evaporation Process

    PubMed Central

    2009-01-01

    A novel double-layer nanostructure of silicon carbide and tungsten oxide is synthesized by a two-step thermal evaporation process using NiO as the catalyst. First, SiC nanowires are grown on Si substrate and then high density W18O49nanorods are grown on these SiC nanowires to form a double-layer nanostructure. XRD and TEM analysis revealed that the synthesized nanostructures are well crystalline. The growth of W18O49nanorods on SiC nanowires is explained on the basis of vapor–solid (VS) mechanism. The reasonably better turn-on field (5.4 V/μm) measured from the field emission measurements suggest that the synthesized nanostructures could be used as potential field emitters. PMID:20596292

  4. Measure Guideline: Evaporative Condensers

    SciTech Connect

    German, A.; Dakin, B.; Hoeschele, M.

    2012-03-01

    The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

  5. Performance of a Water Recirculation Loop Maintenance Device and Process for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Rector, Tony; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2012-01-01

    A water loop maintenance device and process to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been undergoing a performance evaluation. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the water recirculation maintenance device and process is to further enhance this advantage through the leveraging of fluid loop management lessons-learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance process further leverages a sorbent developed for ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware. This

  6. Experimental Investigation of the Change in Temperature at the Center of a Water Droplet in the Process of Evaporation in Heated Air

    NASA Astrophysics Data System (ADS)

    Zakharevich, A. V.; Kuznetsov, G. V.; Strizhak, P. A.

    2016-05-01

    The paper presents the results of an experimental investigation of the change in the temperature at the interface between water and a thermocouple junction (of diameter 1 mm) in a droplet (initial radius 1.5-3 mm) in the process of heating and evaporation of the latter in an air stream (of temperature 350-800 K at the velocity of motion 0.1-3.5 m/s). The lifetimes of droplets (of their complete evaporation) have been determined. It is shown that the temperature at the droplet center changes by no more than 10 K in the process of evaporation at gas temperatures of less than 500 K. At higher temperatures of the external gas medium the droplet is heated intensely (the temperature field is homogeneous).

  7. 242-A Evaporator/plutonium uranium extraction (PUREX) effluent treatment facility (ETF) nonradioactive air emission test report

    SciTech Connect

    Hill, J.S., Westinghouse Hanford

    1996-05-10

    This report shows the methods used to test the stack gas outlet concentration and emission rate of Volatile Organic Compounds as Total Non-Methane Hydrocarbons in parts per million by volume,grams per dry standard cubic meter, and grams per minute from the PUREX ETF stream number G6 on the Hanford Site. Test results are shown in Appendix B.1.

  8. High-level waste storage tank farms/242-A evaporator standards/requirements identification document (S/RID), Vol. 7

    SciTech Connect

    Not Available

    1994-04-01

    This Requirements Identification Document (RID) describes an Occupational Health and Safety Program as defined through the Relevant DOE Orders, regulations, industry codes/standards, industry guidance documents and, as appropriate, good industry practice. The definition of an Occupational Health and Safety Program as specified by this document is intended to address Defense Nuclear Facilities Safety Board Recommendations 90-2 and 91-1, which call for the strengthening of DOE complex activities through the identification and application of relevant standards which supplement or exceed requirements mandated by DOE Orders. This RID applies to the activities, personnel, structures, systems, components, and programs involved in maintaining the facility and executing the mission of the High-Level Waste Storage Tank Farms.

  9. High-level waste storage tank farms/242-A evaporator standards/requirements identification document (S/RID), Vol. 6

    SciTech Connect

    Not Available

    1994-04-01

    The scope of the Environmental Restoration and Waste Management (EM) Functional Area includes the programmatic controls associated with the management and operation of the Hanford Tank Farm Facility. The driving management organization implementing the programmatic controls is the Tank Farms Waste Management (WM)organization whose responsibilities are to ensure that performance objectives are established; and that measurable criteria for attaining objectives are defined and reflected in programs, policies and procedures. Objectives for the WM Program include waste minimization, establishment of effective waste segregation methods, waste treatment technology development, radioactive (low-level, high-level) hazardous and mixed waste transfer, treatment, and storage, applicability of a corrective action program, and management and applicability of a decontamination and decommissioning (D&D) program in future years.

  10. High-level waste storage tank farms/242-A evaporator standards/requirements identification document (S/RID), Vol. 3

    SciTech Connect

    Not Available

    1994-04-01

    The Safeguards and Security (S&S) Functional Area address the programmatic and technical requirements, controls, and standards which assure compliance with applicable S&S laws and regulations. Numerous S&S responsibilities are performed on behalf of the Tank Farm Facility by site level organizations. Certain other responsibilities are shared, and the remainder are the sole responsibility of the Tank Farm Facility. This Requirements Identification Document describes a complete functional Safeguards and Security Program that is presumed to be the responsibility of the Tank Farm Facility. The following list identifies the programmatic elements in the S&S Functional Area: Program Management, Protection Program Scope and Evaluation, Personnel Security, Physical Security Systems, Protection Program Operations, Material Control and Accountability, Information Security, and Key Program Interfaces.

  11. High-level waste storage tank farms/242-A evaporator standards/requirements identification document (S/RID), Vol. 2

    SciTech Connect

    Not Available

    1994-04-01

    The Quality Assurance Functional Area Requirements Identification Document (RID), addresses the programmatic requirements that ensure risks and environmental impacts are minimized, ensure safety, reliability, and performance are maximized through the application of effective management systems commensurate with the risks posed by the Tank Farm Facility and its operation. This RID incorporates guidance intended to provide Tank Farms management with the necessary requirements information to develop, upgrade, or assess the effectiveness of a Quality Assurance Program in the performance of organizational and functional activities. Quality Assurance is defined as all those planned and systematic actions necessary to provide adequate confidence that a facility, structure, system, or component will perform satisfactorily and safely in service. This document will provide the specific requirements to meet DNFSB recommendations and the guidance provided in DOE Order 5700.6C, utilizing industry codes, standards, regulatory guidelines, and industry good practices that have proven to be essential elements for an effective and efficient Quality Assurance Program as the nuclear industry has matured over the last thirty years.

  12. High level waste storage tank farms/242-A evaporator standards/requirements identification document phase 1 assessment report

    SciTech Connect

    Biebesheimer, E., Westinghouse Hanford Co.

    1996-09-30

    This document, the Standards/Requirements Identification Document (S/RID) Phase I Assessment Report for the subject facility, represents the results of an Administrative Assessment to determine whether S/RID requirements are fully addressed by existing policies, plans or procedures. It contains; compliance status, remedial actions, and an implementing manuals report linking S/RID elements to requirement source to implementing manual and section.

  13. High-level waste storage tank farms/242-A evaporator standards/requirements identification document (S/RID), Vol. 5

    SciTech Connect

    Not Available

    1994-04-01

    The Fire Protection functional area for the Hanford Site Tank Farm facilities and support structures is based on the application of relevant DOE orders, regulations, and industry codes and standards. The fire protection program defined in this document may be divided into three areas: (1) organizational, (2) administrative programmatic features, and (3) technical features. The information presented in each section is in the form of program elements and orders, regulations, industry codes, and standards that serve as the attributes of a fire protection program for the Tank Farm facilities. Upon completion this document will be utilized as the basis to evaluate compliance of the fire protection program being implemented for the Tank Farm facilities with the requirements of DOE orders and industry codes and standards.

  14. Dynamic mean field theory of condensation and evaporation processes for fluids in porous materials: application to partial drying and drying.

    PubMed

    Edison, J R; Monson, P A

    2010-01-01

    We study the dynamics of evaporation for lattice gas models of fluids in porous materials using a recently developed dynamic mean field theory. The theory yields a description of the dynamics that is consistent with the mean field theory of the thermodynamics at equilibrium. The nucleation processes associated with phase changes in the pore are emergent features of the dynamics. Our focus is on situations where there is partial drying or drying in the system, associated with weakly attractive or repulsive interactions between the fluid and the pore walls. We consider two systems in this work: (i) a two-dimensional slit pore geometry relevant to the study of adsorption/desorption or intrusion/extrusion dynamics for fluids in porous materials and (ii) a three dimensional slit pore modeling a pair of square plates in a bath of liquid as used in recent theoretical studies of dewetting processes between hydrophobic surfaces. We assess the theory by comparison with a higher order approximation to the dynamics that yields the Bethe-Peierls or quasi-chemical approximation at equilibrium. PMID:21043421

  15. Evaporating firewalls

    NASA Astrophysics Data System (ADS)

    Van Raamsdonk, Mark

    2014-11-01

    In this note, we begin by presenting an argument suggesting that large AdS black holes dual to typical high-energy pure states of a single holographic CFT must have some structure at the horizon, i.e. a fuzzball/firewall, unless the procedure to probe physics behind the horizon is state-dependent. By weakly coupling the CFT to an auxiliary system, such a black hole can be made to evaporate. In a case where the auxiliary system is a second identical CFT, it is possible (for specific initial states) that the system evolves to precisely the thermofield double state as the original black hole evaporates. In this case, the dual geometry should include the "late-time" part of the eternal AdS black hole spacetime which includes smooth spacetime behind the horizon of the original black hole. Thus, if a firewall is present initially, it evaporates. This provides a specific realization of the recent ideas of Maldacena and Susskind that the existence of smooth spacetime behind the horizon of an evaporating black hole can be enabled by maximal entanglement with a Hawking radiation system (in our case the second CFT) rather than prevented by it. For initial states which are not finely-tuned to produce the thermofield double state, the question of whether a late-time infalling observer experiences a firewall translates to a question about the gravity dual of a typical high-energy state of a two-CFT system.

  16. 32 CFR 242a.4 - Grounds on which meetings may be closed, or information may be withheld.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 2 2011-07-01 2011-07-01 false Grounds on which meetings may be closed, or information may be withheld. 242a.4 Section 242a.4 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PUBLIC MEETING PROCEDURES OF THE BOARD OF REGENTS, UNIFORMED SERVICES UNIVERSITY OF...

  17. 32 CFR 242a.4 - Grounds on which meetings may be closed, or information may be withheld.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Grounds on which meetings may be closed, or information may be withheld. 242a.4 Section 242a.4 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PUBLIC MEETING PROCEDURES OF THE BOARD OF REGENTS, UNIFORMED SERVICES UNIVERSITY OF...

  18. Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Quarterly technical progress report, October 1--December 31, 1993

    SciTech Connect

    Boysen, J.; Morotti, J.

    1994-01-01

    The use of freeze-crystallization processes for the treatment of contaminated water is rapidly being acknowledged as a low cost and low energy consuming method for the purification of water contaminated by a wide variety of contaminants of highly variable concentrations. Water purification by using natural conditions to promote freezing appears to be an extremely attractive freeze-crystallization process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions with favorable climatic conditions. The objectives of this research are related to development of a commercially-economic natural freeze-thaw/evaporation (FTE) process for the treatment and purification of water produced in conjunction with oil and gas.

  19. Structure and crystallization process of a thin film prepared by vacuum evaporation of SnO 2 powder

    NASA Astrophysics Data System (ADS)

    Kaito, Chihiro; Saito, Yoshio

    1986-12-01

    An amorphous tin oxide film 10 nm thick has been prepared by vacuum evaporation of SnO 2 powder from a tungsten boat onto a cleaved surface of rock salt. Analyses of electron diffraction patterns and high resolution electron microscope (HREM) images showed that the film was composed of microcrystallites of SnO 3, 2.5 nm in size. An electron beam of the order of 0.1 A/mm 2 was used to irradiate the film, causing the micro-crystallites to change to the rutile structure of SnO 2 with a crystallite size of a few tens of nm. On further irradiation with an intense electron beam, SnO crystals about 10 nm in size appeared. A further increase in radiation energy resulted in larger crystallites containing crystal shear (CS) structures of two types in reduced SnO crystals. The growth process of SnO 2, SnO and CS structure of SnO are discussed on the basis of the prefered orientation of formed crystals.

  20. Structure and optical properties of one-dimensional ZnS nanostructures synthesized using a single evaporation process

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    Zinc sulfide (ZnS) nanostructures with different morphologies and microstructures were synthesized using a single thermal evaporation process. The microstructure and photoluminescence properties of the ZnS nanowires produced in four different temperature zones were examined. Scanning electron microscopy showed that as the substrate temperature decreased, the morphology of the ZnS nanowires changed from a longer curved morphology to a shorter earthworm-like morphology. X-ray diffraction (XRD) shows that all samples were mixtures of a zincblende-structured ZnS phase and a wurtzite-structured ZnS phase and that dominance of the zincblende phase tends to increase with decreasing substrate temperature. The zincblende phase appeared to be dominant regardless of the substrate temperature. A closer comparison of the XRD patterns of the products in the different temperature zones showed that dominance of the zincblende phase tends to increase with decreasing substrate temperature. Photoluminescence spectroscopy revealed a decrease in emission intensity with decreasing substrate temperature. ZnS nanostructures synthesized in temperature zones 2, 3 and 4 (∼ 900, ∼ 800 and ∼ 700 °C, respectively) showed green emission, whereas those synthesized in temperature zone 5 (∼ 600 °C) showed yellow emission. The origins of the emissions are also discussed.

  1. Process for separating dissolved solids from a liquid using an anti-solvent and multiple effect evaporators

    DOEpatents

    Daniels, E.J.; Jody, B.J.; Bonsignore, P.V.

    1994-07-19

    A process and system are disclosed for treating aluminum salt cake containing water soluble halide salts by contacting the salt cake with water to dissolve water soluble halide salts forming a saturated brine solution. Transporting a portion of about 25% of the saturated brine solution to a reactor and introducing into the saturated brine solution at least an equal volume of a water-miscible low-boiling organic material such as acetone to precipitate a portion of the dissolved halide salts forming a three-phase mixture of an aqueous-organic-salt solution phase and a precipitated salt phase and an organic rich phase. The precipitated salt phase is separated from the other phases and the organic rich phase is recycled to the reactor. The remainder of the saturated brine solution is sent to a multiple effect evaporator having a plurality of stages with the last stage thereof producing low grade steam which is used to boil off the organic portion of the solution which is recycled. 3 figs.

  2. Process for separating dissolved solids from a liquid using an anti-solvent and multiple effect evaporators

    DOEpatents

    Daniels, Edward J.; Jody, Bassam J.; Bonsignore, Patrick V.

    1994-01-01

    A process and system for treating aluminum salt cake containing water soluble halide salts by contacting the salt cake with water to dissolve water soluble halide salts forming a saturated brine solution. Transporting a portion of about 25% of the saturated brine solution to a reactor and introducing into the saturated brine solution at least an equal volume of a water-miscible low-boiling organic material such as acetone to precipitate a portion of the dissolved halide salts forming a three-phase mixture of an aqueous-organic-salt solution phase and a precipitated salt phase and an organic rich phase. The precipitated salt phase is separated from the other phases and the organic rich phase is recycled to the reactor. The remainder of the saturated brine solution is sent to a multiple effect evaporator having a plurality of stages with the last stage thereof producing low grade steam which is used to boil off the organic portion of the solution which is recycled.

  3. Streamer Evaporation

    NASA Technical Reports Server (NTRS)

    Suess, S. T.; Wang, A.-H.; Wu, S. T.; Nerney, S. F.

    1998-01-01

    Evaporation is the consequence of heating near the top of streamers in ideal Magnetohydrodynamics (MHD) models, where the plasma is weakly contained by the magnetic field. Heating causes slow opening of field lines and release of new solar wind. It was discovered in simulations and, due to the absence of loss mechanisms, the ultimate end point is the complete evaporation of the streamer. Of course streamers do not behave in this way because there are losses by thermal conduction and radiation. Physically, heating is also expected to depend on ambient conditions. We use our global MHD model with thermal conduction to examine the effect of changing the heating scale height. We also apply and extend an analytic model of streamers developed by Pneuman (1968) to show that steady streamers are unable to contain plasma for temperatures near the cusp greater than approximately 2 x 10(exp 6) K.

  4. Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Quarterly technical progress report, April 1, 1994--June 30, 1994

    SciTech Connect

    Boysen, J.; Morotti, J.

    1994-07-01

    The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year-round in regions where subfreezing temperatures seasonally occur. The objectives of this research are related to development of a commercially-economic natural freeze-thaw/evaporation (FTE) process for the treatment and purification of water produced in conjunction with oil and gas.

  5. Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Quarterly technical progress report, October 1, 1995--December 31, 1995

    SciTech Connect

    Boysen, J.; Morotti, J.

    1996-01-01

    The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year-round in regions where sub-freezing temperatures seasonally occur. The objectives of this research are related to development of a commercially-economic natural freeze-thaw/evaporation (FTE) process for the treatment and purification of water produced in conjunction with oil and gas.

  6. RESULTS OF GROUNDWATER MONITORING FOR THE 183-H SOLAR EVAPORATION BASINS AND 300 AREA PROCESS TRENCHES JANUARY THRU JUNE 2008

    SciTech Connect

    HARTMAN MJ

    2008-11-04

    This is one of a series of reports on Resource Conservation and Recovery Act of 1976 (RCRA) monitoring at the 183-H solar evaporation basins and the 300 Area process trenches. It fulfills the requirement of Washington Administrative Code (WAC) 173-303-645(11)(g), 'Release from Regulated Units', to report twice each year on the effectiveness of the corrective action program. This report covers the period from January through June 2008. The current objective of corrective action monitoring the 183-H basins is simply to track trends. Although there is short-term variability in contaminant concentrations, trends over the past 10 years are downward. The current Hanford Facility RCRA Permit (Dangerous Waste Portion of the Resource Conservation and Recovery Act Permit for the Treatment, Storage, and Disposal of Dangerous Waste [Permit No. WA 7890008967]) and monitoring plan remain adequate for the objective of tracking trends. The objective of groundwater monitoring at the 300 Area process trenches is to demonstrate the effectiveness of the corrective action program by examining the trend of the constituents of interest to confirm that they are attenuating naturally. The overall concentration of uranium in network wells remained above the 30 {micro}g/L drinking water standard in the three downgradient wells screened at the water table. Fluctuations of uranium concentration are caused by changes in river stage. The concentration of cis-1,2-dichloroethene remained above the 70 {micro}g/L drinking water standard in one well (399-1-16B). Concentrations are relatively steady at this well and are not affected by river stage. Trichloroethene and tetrachloroethene concentrations were below detection limits in all wells during the reporting period.

  7. Evaporation- and Solution-Process-Feasible Highly Efficient Thianthrene-9,9',10,10'-Tetraoxide-Based Thermally Activated Delayed Fluorescence Emitters with Reduced Efficiency Roll-Off.

    PubMed

    Xie, Gaozhan; Li, Xianglong; Chen, Dongjun; Wang, Zhiheng; Cai, Xinyi; Chen, Dongcheng; Li, Yunchuan; Liu, Kunkun; Cao, Yong; Su, Shi-Jian

    2016-01-01

    Two novel evaporation- and solution-process-feasible thermally activated delayed fluorescence emitters, green-light-emission ACRDSO2 and yellow-light-emission PXZDSO2, based on a brand-new electron-acceptor moiety thianthrene-9,9',10,10'-tetraoxide, are developed for organic light-emitting diodes. The solution-processed devices, without any hole-transport layer, exhibit competitive performance and reduced efficiency roll-off compared with corresponding vacuum-deposited devices. PMID:26551788

  8. Radial water infiltration advance evaporation processes during irrigation using point source emitters in rigid and swelling soils

    NASA Astrophysics Data System (ADS)

    Su, Ninghu

    2007-10-01

    SummaryIn this paper we investigate the dynamic water balance of radial flows during irrigation using point source emitters. The components of radial flows of this kind include infiltration simultaneously coupled to the storage and advance on the soil surface, and evaporation into the air while the source continuously supplies water. The soils we consider here can be rigid or swelling. Because the infiltration equations reported for both rigid and swelling soils have an identical mathematical structure, the analysis for rigid soils using Philip's two-term infiltration equation applies to both swelling and rigid soils. As such, we emphasise that our analysis is applicable to both rigid and swelling soils. We first extend the radial Lewis-Milne equation (RLME) given by Rasmussen to analyse the radial flow mechanics by incorporating evaporation as a key component in the radial dynamic water balance. Then we present a set of four solutions of the RLME using Philip's two-parameter infiltration equation and two-term and three-term equations for cumulative evaporation. With the two-term cumulative evaporation equation, we show that the three solutions yield a simple identical asymptotic formulae at large times, which can be used to design the area to be irrigated, or to derive the final infiltration rate, A, and the final evaporation rate, E2. Analyses show that evaporation plays an important role in the radial dynamic water balance at large times, and as expected it plays a minor role during the early stage of irrigation (small time solutions).

  9. Fast Assembly of Gold Nanoparticles in Large-Area 2D Nanogrids Using a One-Step, Near-Infrared Radiation-Assisted Evaporation Process.

    PubMed

    Utgenannt, André; Maspero, Ross; Fortini, Andrea; Turner, Rebecca; Florescu, Marian; Jeynes, Christopher; Kanaras, Antonios G; Muskens, Otto L; Sear, Richard P; Keddie, Joseph L

    2016-02-23

    When fabricating photonic crystals from suspensions in volatile liquids using the horizontal deposition method, the conventional approach is to evaporate slowly to increase the time for particles to settle in an ordered, periodic close-packed structure. Here, we show that the greatest ordering of 10 nm aqueous gold nanoparticles (AuNPs) in a template of larger spherical polymer particles (mean diameter of 338 nm) is achieved with very fast water evaporation rates obtained with near-infrared radiative heating. Fabrication of arrays over areas of a few cm(2) takes only 7 min. The assembly process requires that the evaporation rate is fast relative to the particles' Brownian diffusion. Then a two-dimensional colloidal crystal forms at the falling surface, which acts as a sieve through which the AuNPs pass, according to our Langevin dynamics computer simulations. With sufficiently fast evaporation rates, we create a hybrid structure consisting of a two-dimensional AuNP nanoarray (or "nanogrid") on top of a three-dimensional polymer opal. The process is simple, fast, and one-step. The interplay between the optical response of the plasmonic Au nanoarray and the microstructuring of the photonic opal results in unusual optical spectra with two extinction peaks, which are analyzed via finite-difference time-domain method simulations. Comparison between experimental and modeling results reveals a strong interplay of plasmonic modes and collective photonic effects, including the formation of a high-order stopband and slow-light-enhanced plasmonic absorption. The structures, and hence their optical signatures, are tuned by adjusting the evaporation rate via the infrared power density. PMID:26767891

  10. Optimization of evaporative cooling

    NASA Astrophysics Data System (ADS)

    Sackett, C. A.; Bradley, C. C.; Hulet, R. G.

    1997-05-01

    Recent experiments have used forced evaporative cooling to produce Bose-Einstein condensation in dilute gases. The evaporative cooling process can be optimized to provide the maximum phase-space density with a specified number of atoms remaining. We show that this global optimization is approximately achieved by locally optimizing the cooling efficiency at each instant. We discuss how this method can be implemented, and present the results for our 7Li trap. The predicted behavior of the gas is found to agree well with experiment.

  11. Fundamental study of Ti feedstock evaporation and the precursor formation process in inductively coupled thermal plasmas during TiO2 nanopowder synthesis

    NASA Astrophysics Data System (ADS)

    Kodama, Naoto; Tanaka, Yasunori; Kita, K.; Ishisaka, Y.; Uesugi, Y.; Ishijima, T.; Sueyasu, S.; Nakamura, K.

    2016-08-01

    Two-dimensional spectroscopic observations were conducted for an inductively coupled thermal plasma (ICTP) torch during TiO2 nanopowder synthesis. The feedstock was injected intermittently into the ICTP torch to investigate the Ti feedstock evaporation process clearly and to elucidate the formation process of precursor species. Spatiotemporal distributions of Ti atomic lines and TiO spectra were observed simultaneously inside the plasma torch with the observation system developed. The observation results showed that the injected Ti feedstock was evaporated to form high-density Ti atomic vapour in the torch, and that the generated Ti atomic vapour is transported and diffused by gas flow and the density gradient. In addition, TiO molecular vapour was generated almost simultaneously around the on-axis region in the torch.

  12. Molecular Mechanism of Water Evaporation

    NASA Astrophysics Data System (ADS)

    Nagata, Yuki; Usui, Kota; Bonn, Mischa

    2015-12-01

    Evaporation is the process by which water changes from a liquid to a gas or vapor, and is a key step in Earth's water cycle. At the molecular level, evaporation requires breaking at least one very strong intermolecular bond between two water molecules at the interface. Despite the importance of this process the molecular mechanism by which an evaporating water molecule gains sufficient energy to escape from the surface has remained elusive. Here, we show, using molecular dynamics simulations at the water-air interface with polarizable classical force field models, that the high kinetic energy of the evaporated water molecule is enabled by a well-timed making and breaking of hydrogen bonds involving at least three water molecules at the interface, the recoil of which allows one of the molecules to escape. The evaporation of water is thus enabled by concerted, ultrafast hydrogen-bond dynamics of interfacial water, and follows one specific molecular pathway.

  13. A numerical method for integrating the kinetic equations of droplet spectra evolution by condensation/evaporation and by coalescence/breakup processes

    NASA Technical Reports Server (NTRS)

    Emukashvily, I. M.

    1982-01-01

    An extension of the method of moments is developed for the numerical integration of the kinetic equations of droplet spectra evolution by condensation/evaporation and by coalescence/breakup processes. The number density function n sub k (x,t) in each separate droplet packet between droplet mass grid points (x sub k, x sub k+1) is represented by an expansion in orthogonal polynomials with a given weighting function. In this way droplet number concentrations, liquid water contents and other moments in each droplet packet are conserved and the problem of solving the kinetic equations is replaced by one of solving a set of coupled differential equations for the number density function moments. The method is tested against analytic solutions of the corresponding kinetic equations. Numerical results are obtained for different coalescence/breakup and condensation/evaporation kernels and for different initial droplet spectra. Also droplet mass grid intervals, weighting functions, and time steps are varied.

  14. Sampling and Analysis for Tank 241-AW-104 Waste in Support of Evaporator Campaign 2001-1

    SciTech Connect

    MCKINNEY, S.G.

    2000-05-23

    This Tank Sampling and Analysis Plan (TSAP) identifies sample collection, laboratory analysis, quality assurance/quality control (QA/QC), and reporting objectives for the characterization of tank 241-AW-104 waste. Technical bases for these objectives are specified in the 242-A Evaporator Data Quality Objectives (Bowman 2000a and Von Bargen 1998), 242-A Evaporator Quality Assurance Project Plan (Bowman 1998 and Bowman 2000b), Tank 241-AW-104 Sampling Requirements in Support of Evaporator Campaign 2000-1 (Le 2000). Characterization results will be used to support the evaporator campaign currently planned for early fiscal year 2001. No other needs (or issues) requiring data for this tank waste apply to this sampling event.

  15. Iodine retention during evaporative volume reduction

    DOEpatents

    Godbee, H.W.; Cathers, G.I.; Blanco, R.E.

    1975-11-18

    An improved method for retaining radioactive iodine in aqueous waste solutions during volume reduction is disclosed. The method applies to evaporative volume reduction processes whereby the decontaminated (evaporated) water can be returned safely to the environment. The method generally comprises isotopically diluting the waste solution with a nonradioactive iodide and maintaining the solution at a high pH during evaporation.

  16. Preparation of novel layer-stack hexagonal CdO micro-rods by a pre-oxidation and subsequent evaporation process

    SciTech Connect

    Peng, Kun; Jiang, Pan; Zhu, Jiajun; Zhou, Lingping; Li, Deyi

    2014-12-15

    Graphical abstract: Layer-stack hexagonal cadmium oxide (CdO) micro-rods were prepared. - Highlights: • Novel hexagonal layer-stack structure CdO micro-rods were synthesized by a thermal evaporation method. • The pre-oxidation, vapor pressure and substrate nature play a key role on the formation of CdO rods. • The formation mechanism of CdO micro-rods was explained. - Abstract: Novel layer-stack hexagonal cadmium oxide (CdO) micro-rods were prepared by pre-oxidizing Cd granules and subsequent thermal oxidation under normal atmospheric pressure. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to characterize the phase structure and microstructure. The pre-oxidation process, vapor pressure and substrate nature were the key factors for the formation of CdO micro-rods. The diameter of micro-rod and surface rough increased with increasing of thermal evaporation temperature, the length of micro-rod increased with the increasing of evaporation time. The formation of hexagonal layer-stack structure was explained by a vapor–solid mechanism.

  17. X-ray-based measurement of composition during electron beam melting of AISI 316 stainless steel: Part II. Evaporative processes and simulation

    NASA Astrophysics Data System (ADS)

    Ritchie, M.; Lee, P. D.; Mitchell, A.; Cockcroft, S. L.; Wang, T.

    2003-03-01

    An energy dispersive X-ray (EDX) detector mounted on a laboratory scale electron beam furnace (30 kW) was employed to assess the potential use of X-rays as a means of on-line composition monitoring during electron beam (E B) melting of alloys. The design and construction of the collimation and protection systems used for the EDX are described in Part I. In Part II, a mathematical simulation of the heat, mass, and momentum transfer was performed for comparison to the EDX and vapor deposition results. The predicted flow patterns and evaporation rates are used to explain the differences between the two experimental methods. For the EDX spectra measured, the X-rays generated were from the center of the hearth where fluid flow rising from the bulk of the pool is sufficient to maintain the bulk composition despite the high evaporative flux from the surface. The flow moves radially outward from the center of the pool, with the volatile species being depleted. The vapor deposition technique measures the entire region, giving an average surface composition, and it therefore differs from the EDX results, which gave a near bulk composition. This combined study using in-situ EDX measurements and numerical simulations both provided an insight into the phenomena controlling the evaporation in an EB-heated system and demonstrated the viability of using EDX to measure the bulk composition during EB melting processes.

  18. Determining the virtual surface in the thermal evaporation process of magnesium fluoride from a tungsten boat for different deposition rates, to be used in precision optical components

    NASA Astrophysics Data System (ADS)

    Tejada Esteves, A.; Gálvez de la Puente, G.

    2013-11-01

    Vacuum thermal evaporation has, for some time now, been the principal method for the deposition of thin films, given, among other aspects, its simplicity, flexibility, and relatively low cost. Therefore, the development of models attempting to predict the deposition patterns of given thin film materials in different locations of a vacuum evaporation chamber are arguably important. With this in mind, we have designed one of such models for the thermal evaporation process of magnesium fluoride (MgF2), a common material used in optical thin films, originating from a tungsten boat source. For this we took several deposition samples in glass slide substrates at different locations in the vacuum chamber, considering as independent variables the mean deposition rate, and the axial and vertical distances of the source to the substrate. After a careful analysis by matrix method from the spectral transmittance data of the samples, while providing as output data the spectral transmittance, as well as the physical thickness of the films, both as functions of the aforementioned variables, the virtual surface of the source was determined.

  19. Secondary Organic Aerosol Formation by Cloud Processing: Accretion Reactions Involving Glyoxal and Methylglyoxal in Evaporating Cloud Droplets

    NASA Astrophysics Data System (ADS)

    de Haan, D. O.; Hastings, W. P.; Corrigan, A. L.; Lee, F. E.; Hanley, S. W.

    2006-12-01

    Glyoxal and methyl glyoxal are dicarbonyl compounds found in atmospheric cloud and fog water, typically at low micromolar concentrations. These two compounds are known to form copolymers under certain industrial conditions by the nucleophilic addition of S, N and O-containing molecules. We report ambient FTIR-ATR and particle chamber data on a range of reactions between glyoxal and S, N and O-containing molecules found in cloudwater, some of which are triggered by droplet evaporation. Liquid-phase formation of adducts between glyoxal and S(IV) is seen to halt sulfur oxidation during droplet drying on the ATR crystal. Formation of glyoxal / S(VI) adducts, however, are not observed by ATR. At neutral or acidic pH, droplet evaporation triggers a reaction between glyoxal and amino acids in the residue left behind, forming imines. Glyoxal reacts under similar conditions with glycol compounds, forming cyclic acetals, but not with sugars, perhaps due to a lack of conformational freedom. Glyoxal is not observed to react with carboxylic acids, either in particle chambers or while drying on an ATR crystal.

  20. Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Quarterly technical progress report, January 1--March 31, 1994

    SciTech Connect

    Boysen, J.; Morotti, J.

    1994-04-01

    The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions where subfreezing temperatures seasonally occur. The objectives of this research are related to development of a commercially-economic natural freeze-thaw/evaporation (FTE) process for the treatment and purification of water produced in conjunction with oil and gas. During the reporting period of 1/1/94 to 3/31/94, project research concentrated on Subtasks 2.0 (Task 2 Project Reporting) and 2.1 (Laboratory-scale FTE Simulations) . The objectives of Task 2 are to conduct laboratory- and bench-scale simulations for optimizing the design of the FTE process. Task 2 requires completion of six subtasks: Subtask 2.0 - Task 2 Project Reporting (initiated 3/1/93), Subtask 2.1 - Laboratory-scale FTE Simulations, Subtask 2.2 Re-evaluation of Process Economics Based on Laboratory-scale Process Simulation Results, Subtask 2.3 - Bench-scale FTE Simulations, Subtask 2.4 - Economic Assessment of Bench-scale Simulations, and Subtask 2.5 - Technical Report of Task 2. The construction, shakedown, and operation of the laboratory-scale process simulations planned were planned for this quarter (Subtask 2.1).

  1. Flash evaporation from turbulent water jets

    NASA Astrophysics Data System (ADS)

    Bharathan, D.; Penney, T.

    1983-02-01

    Results of an experimental investigation of flash evaporation from turbulent planar and axisymmetric water jets are reported. In the range of jet thicknesses tested, for planar jets, due to shattering, evaporation is found to be nearly independent of the jet thickness. Evaporation from the planar jets was found to be dependent on the initial level of turbulence in the water supply manifold. An approximate analysis to model the evaporation process based on the physical phenomena and experimental observations is outlined. Comparisons between the experimental data and analytical predictions of the liquid temperature variation along the jet are included. Use of screens in the water jet are shown to be effective for enhancing evaporation.

  2. Effects of gold catalysts and thermal evaporation method modifications on the growth process of Zn{sub 1-x}Mg{sub x}O nanowires

    SciTech Connect

    Yousefi, Ramin; Muhamad, Muhamad Rasat

    2010-07-15

    In this paper, we investigate the roles of gold catalysts and thermal evaporation method modifications in the growth process of Zn{sub 1-x}Mg{sub x}O nanowires. Zn{sub 1-x}Mg{sub x}O nanowires are fabricated on silicon substrates with and without using a gold catalyst. Characterizations reveal that Mg acts in a self-catalyst role during the growth process of Zn{sub 1-x}Mg{sub x}O nanowires grown on catalyst-free substrate. The optical properties and crystalline quality of the Zn{sub 1-x}Mg{sub x}O nanowires are characterized by room temperature photoluminescence (PL) measurements and Raman spectroscopy, respectively. The Raman and PL studies demonstrate that the Zn{sub 1-x}Mg{sub x}O nanowires grown using the catalyst-free method have good crystallinity with excellent optical properties and have a larger band-gap in comparison to those grown with the assistance of gold. - Graphical abstract: ZnMgO nanowires can be formed with and without gold catalyst by a modified thermal evaporation method.

  3. DWPF Recycle Evaporator Simulant Tests

    SciTech Connect

    Stone, M

    2005-04-05

    Testing was performed to determine the feasibility and processing characteristics of an evaporation process to reduce the volume of the recycle stream from the Defense Waste Processing Facility (DWPF). The concentrated recycle would be returned to DWPF while the overhead condensate would be transferred to the Effluent Treatment Plant. Various blends of evaporator feed were tested using simulants developed from characterization of actual recycle streams from DWPF and input from DWPF-Engineering. The simulated feed was evaporated in laboratory scale apparatus to target a 30X volume reduction. Condensate and concentrate samples from each run were analyzed and the process characteristics (foaming, scaling, etc) were visually monitored during each run. The following conclusions were made from the testing: Concentration of the ''typical'' recycle stream in DWPF by 30X was feasible. The addition of DWTT recycle streams to the typical recycle stream raises the solids content of the evaporator feed considerably and lowers the amount of concentration that can be achieved. Foaming was noted during all evaporation tests and must be addressed prior to operation of the full-scale evaporator. Tests were conducted that identified Dow Corning 2210 as an antifoam candidate that warrants further evaluation. The condensate has the potential to exceed the ETP WAC for mercury, silicon, and TOC. Controlling the amount of equipment decontamination recycle in the evaporator blend would help meet the TOC limits. The evaporator condensate will be saturated with mercury and elemental mercury will collect in the evaporator condensate collection vessel. No scaling on heating surfaces was noted during the tests, but splatter onto the walls of the evaporation vessels led to a buildup of solids. These solids were difficult to remove with 2M nitric acid. Precipitation of solids was not noted during the testing. Some of the aluminum present in the recycle streams was converted from gibbsite to

  4. Treatment of digestate from a co-digestion biogas plant by means of vacuum evaporation: tests for process optimization and environmental sustainability.

    PubMed

    Chiumenti, A; da Borso, F; Chiumenti, R; Teri, F; Segantin, P

    2013-06-01

    Vacuum evaporation consists in the boiling of a liquid substrate at negative pressure, at a temperature lower than typical boiling temperature at atmospheric conditions. Condensed vapor represents the so called condensate, while the remaining substrate represents the concentrate. This technology is derived from other sectors and is mainly dedicated to the recovery of chemicals from industrial by-products, while it has not been widely implemented yet in the field of agricultural digestate treatment. The present paper relates on experimental tests performed in pilot-scale vacuum evaporation plants (0.100 and 0.025 m(3)), treating filtered digestate (liquid fraction of digestate filtered by a screw-press separator). Digestate was produced by a 1 MWe anaerobic digestion plant fed with swine manure, corn silage and other biomasses. Different system and process configurations were tested (single-stage and two-stage, with and without acidification) with the main objectives of assessing the technical feasibility and of optimizing process parameters for an eventual technology transfer to full scale systems. The inputs and outputs of the process were subject to characterization and mass and nutrients balances were determined. The vacuum evaporation process determined a relevant mass reduction of digestate. The single stage configuration determined the production of a concentrate, still in liquid phase, with a total solid (TS) mean concentration of 15.0%, representing, in terms of mass, 20.2% of the input; the remaining 79.8% was represented by condensate. The introduction of the second stage allowed to obtain a solid concentrate, characterized by a content of TS of 59.0% and representing 5.6% of initial mass. Nitrogen balance was influenced by digestate pH: in order to limit the stripping of ammonia and its transfer to condensate it was necessary to reduce the pH. At pH 5, 97.5% of total nitrogen remained in the concentrate. This product was characterized by very high

  5. Performance of a Water Recirculation Loop Maintenance Device and Process for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Steele, John W.; Rector, Tony; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2013-01-01

    A dual-bed device to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been designed and is undergoing testing. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the development of a water recirculation maintenance device is to further enhance this advantage through the leveraging of fluid loop management lessons-learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The bed design further leverages a sorbent developed for ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  6. A shortcut for designing evaporators

    SciTech Connect

    Durand, M.I.A.A.

    1996-01-01

    Multiple-effect evaporation is commonly used in chemical process plants to minimize energy consumption and cooling water. In this system, several evaporators are connected by piping so that vapor passes from one effect to the next in series. Thus, the heat supplied to the first evaporator is used to vaporize water in the first effect; this vapor, in turn, passes to the next effect, until, finally, the heat in the vapor supplied to the last effect passes on to the condenser. The net result of this arrangement is the multiple reuse of heat, and a marked increase in the economic of the evaporation system. In addition to savings in steam use, there is also a saving in condenser cooling water as the number of effects increases. On the other hand, an increase in the number of effects represents an increase in capital costs since more heat transfer area is required in the evaporator system. Thus, the choice of the proper--that is, optimum--number of effects is dictated by an economic balance between the savings in steam and cooling water versus that of the additional investment costs. The paper describes the basic equations and an economic analysis of evaporator systems, and illustrates the method with an example.

  7. Influence of process parameters on the size distribution of PLA microcapsules prepared by combining membrane emulsification technique and double emulsion-solvent evaporation method.

    PubMed

    Liu, Rong; Ma, Guang-Hui; Wan, Yin-Hua; Su, Zhi-Guo

    2005-11-10

    Relatively uniform-sized biodegradable poly(lactide) (PLA) microcapsules with various sizes were successfully prepared by combining a glass membrane emulsification technique and water-in-oil-in-water (w1/o/w2) double emulsion-solvent evaporation method. A water phase was used as the internal water phase, a mixture solvent of dichloromethane (DCM) and toluene dissolving PLA and Arlacel 83 was used as the oil phase (o). These two solutions were emulsified by a homogenizer to form a w1/o primary emulsion. The primary emulsion was permeated through the uniform pores of a glass membrane into the external water phase by the pressure of nitrogen gas to form the uniform w1/o/w2 double emulsion droplets. Then, the solid polymer microcapsules were obtained by simply evaporating solvent. The influence of process parameters on the size distribution of PLA microcapsules was investigated, with an emphasis on the effect of oil-soluble emulsifier. A unique phenomenon was found that a large part of emulsifier could adsorb on the interface of internal water phase and oil phase, which suppressed its adsorption on the surface of glass membrane, and led to the successful preparation of uniform-sized double emulsion. Finally, by optimizing the process parameters, PLA microcapsules with various sizes having coefficient of variation (CV) value under 14.0% were obtained. Recombinant human insulin (rhI), as a model protein, was encapsulated into the microcapsules with difference sizes, and its encapsulation efficiency and cumulative release were investigated. The result suggested that the release behavior could be simply adjusted just by changing precisely the diameters of microcapsule, benefited from the membrane emulsification technique. PMID:16198091

  8. Evaporator Cleaning Studies

    SciTech Connect

    Wilmarth, W.R.

    1999-04-15

    Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent operational history of the Evaporator showed significant solid formation in secondary lines and in the evaporator pot. Additional samples remain necessary to ensure material identity in the evaporator pot. Analysis of these future samples will provide actinide partitioning information and dissolution characteristics of the solid material from the pot to ensure safe chemical cleaning.

  9. Advanced evaporator technology progress report FY 1992

    SciTech Connect

    Chamberlain, D.; Hutter, J.C.; Leonard, R.A.

    1995-01-01

    This report summarizes the work that was completed in FY 1992 on the program {open_quotes}Technology Development for Concentrating Process Streams.{close_quotes} The purpose of this program is to evaluate and develop evaporator technology for concentrating radioactive waste and product streams such as those generated by the TRUEX process. Concentrating these streams and minimizing the volume of waste generated can significantly reduce disposal costs; however, equipment to concentrate the streams and recycle the decontaminated condensates must be installed. LICON, Inc., is developing an evaporator that shows a great deal of potential for this application. In this report, concepts that need to be incorporated into the design of an evaporator operated in a radioactive environment are discussed. These concepts include criticality safety, remote operation and maintenance, and materials of construction. Both solubility and vapor-liquid equilibrium data are needed to design an effective process for concentrating process streams. Therefore, literature surveys were completed and are summarized in this report. A model that is being developed to predict vapor phase compositions is described. A laboratory-scale evaporator was purchased and installed to study the evaporation process and to collect additional data. This unit is described in detail. Two new LICON evaporators are being designed for installation at Argonne-East in FY 1993 to process low-level radioactive waste generated throughout the laboratory. They will also provide operating data from a full-sized evaporator processing radioactive solutions. Details on these evaporators are included in this report.

  10. Evaporation in space manufacturing

    NASA Technical Reports Server (NTRS)

    Li, C. H.

    1974-01-01

    'Normal evaporation' equations for predicting the compositional changes with time and temperature have been developed and correlated with actual experimental data. An evaporative congruent temperature is defined and used to explain, predict, or plan space experiments on anomalous constitutional melting (on cooling) or solidification (on heating). Uneven evaporation causes reactive jetting forces capable of initiating new convection currents, nongravitational accelerations, surface vibrations, or other disturbances. Applications of evaporation to space manufacturing are described concerning evaporative purification, surface cooling, specimen selection, particles splitting, freezing data interpretation, material loss and dimensional control, and surface contamination or compositional changes.

  11. Origins of Highly Stable Al-evaporated Solution-processed ZnO Thin Film Transistors: Insights from Low Frequency and Random Telegraph Signal Noise.

    PubMed

    Kim, Joo Hyung; Kang, Tae Sung; Yang, Jung Yup; Hong, Jin Pyo

    2015-01-01

    One long-standing goal in the emerging field of flexible and transparent electronic devices is to meet the demand of key markets, such as enhanced output performance for metal oxide semiconductor thin film transistors (TFTs) prepared by a solution process. While solution-based fabrication techniques are cost-effective and ensure large-area coverage at low temperature, their utilization has the disadvantage of introducing large trap states into TFTs. Such states, the formation of which is induced by intrinsic defects initially produced during preparation, have a significant impact on electrical performance. Therefore, the ability to enhance the electrical characteristics of solution-processed TFTs, along with attaining a firm understanding of their physical nature, remains a key step towards extending their use. In this study, measurements of low-frequency noise and random telegraph signal noise are employed as generic alternative tools to examine the origins of enhanced output performance for solution-processed ZnO TFTs through the control of defect sites by Al evaporation. PMID:26525284

  12. Origins of Highly Stable Al-evaporated Solution-processed ZnO Thin Film Transistors: Insights from Low Frequency and Random Telegraph Signal Noise

    PubMed Central

    Kim, Joo Hyung; Kang, Tae Sung; Yang, Jung Yup; Hong, Jin Pyo

    2015-01-01

    One long-standing goal in the emerging field of flexible and transparent electronic devices is to meet the demand of key markets, such as enhanced output performance for metal oxide semiconductor thin film transistors (TFTs) prepared by a solution process. While solution-based fabrication techniques are cost-effective and ensure large-area coverage at low temperature, their utilization has the disadvantage of introducing large trap states into TFTs. Such states, the formation of which is induced by intrinsic defects initially produced during preparation, have a significant impact on electrical performance. Therefore, the ability to enhance the electrical characteristics of solution-processed TFTs, along with attaining a firm understanding of their physical nature, remains a key step towards extending their use. In this study, measurements of low-frequency noise and random telegraph signal noise are employed as generic alternative tools to examine the origins of enhanced output performance for solution-processed ZnO TFTs through the control of defect sites by Al evaporation. PMID:26525284

  13. Origins of Highly Stable Al-evaporated Solution-processed ZnO Thin Film Transistors: Insights from Low Frequency and Random Telegraph Signal Noise

    NASA Astrophysics Data System (ADS)

    Kim, Joo Hyung; Kang, Tae Sung; Yang, Jung Yup; Hong, Jin Pyo

    2015-11-01

    One long-standing goal in the emerging field of flexible and transparent electronic devices is to meet the demand of key markets, such as enhanced output performance for metal oxide semiconductor thin film transistors (TFTs) prepared by a solution process. While solution-based fabrication techniques are cost-effective and ensure large-area coverage at low temperature, their utilization has the disadvantage of introducing large trap states into TFTs. Such states, the formation of which is induced by intrinsic defects initially produced during preparation, have a significant impact on electrical performance. Therefore, the ability to enhance the electrical characteristics of solution-processed TFTs, along with attaining a firm understanding of their physical nature, remains a key step towards extending their use. In this study, measurements of low-frequency noise and random telegraph signal noise are employed as generic alternative tools to examine the origins of enhanced output performance for solution-processed ZnO TFTs through the control of defect sites by Al evaporation.

  14. Salt stains from evaporating droplets.

    PubMed

    Shahidzadeh, Noushine; Schut, Marthe F L; Desarnaud, Julie; Prat, Marc; Bonn, Daniel

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls , but also very important in many applications such as purification of pharmaceuticals, de-icing of airplanes, inkjet printing and coating applications. In many of these processes, a phase change happens within the drop because of solvent evaporation, temperature changes or chemical reactions, which consequently lead to liquid to solid transitions in the droplets. Here we show that crystallization patterns of evaporating of water drops containing dissolved salts are different from the stains reported for evaporating colloidal suspensions. This happens because during the solvent evaporation, the salts crystallize and grow during the drying. Our results show that the patterns of the resulting salt crystal stains are mainly governed by wetting properties of the emerging crystal as well as the pathway of nucleation and growth, and are independent of the evaporation rate and thermal conductivity of the substrates. PMID:26012481

  15. Salt stains from evaporating droplets

    PubMed Central

    Shahidzadeh, Noushine; Schut, Marthe F. L.; Desarnaud, Julie; Prat, Marc; Bonn, Daniel

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls , but also very important in many applications such as purification of pharmaceuticals, de-icing of airplanes, inkjet printing and coating applications. In many of these processes, a phase change happens within the drop because of solvent evaporation, temperature changes or chemical reactions, which consequently lead to liquid to solid transitions in the droplets. Here we show that crystallization patterns of evaporating of water drops containing dissolved salts are different from the stains reported for evaporating colloidal suspensions. This happens because during the solvent evaporation, the salts crystallize and grow during the drying. Our results show that the patterns of the resulting salt crystal stains are mainly governed by wetting properties of the emerging crystal as well as the pathway of nucleation and growth, and are independent of the evaporation rate and thermal conductivity of the substrates. PMID:26012481

  16. Synthesis of Vertically Aligned ZnO Nanorods on Ni-Based Buffer Layers Using a Thermal Evaporation Process

    NASA Astrophysics Data System (ADS)

    Kuo, Dong-Hau; He, Jheng-Yu; Huang, Ying-Sheng

    2012-03-01

    Uniform, vertically aligned ZnO nanorods have been grown mainly on Au-coated and ZnO-coated sapphire substrates, ZnO- and GaN-coated substrates, or self-catalyzing substrates. Conventionally, Ni-coated substrates have resulted in thick rods with diameter more than 250 nm, rods with nonuniform distribution in diameter, or rods with an alignment problem. In the best result in this paper, slender, uniform, vertically aligned, solely UV-emitting ZnO nanorods with diameter of 110 ± 25 nm and length of 30 ± 10 μm have been successfully grown at 700°C for 2 h on sapphire substrates covered with Ni-based buffer layers by using metallic zinc and oxygen as reactants. Scanning electron microscopy and room-temperature photoluminescence have been used to investigate the effects of process conditions on the slenderness and vertical alignment of the ZnO rods. To develop the desired ZnO nanorods, etched sapphire substrates, a second metallic Sn buffer layer on top of a spin-coated nickel oxide layer, polyvinyl alcohol binder at 10% concentration in solution of iron nitrate, and pyrolysis and reduction reactions were involved. Defect photoemission for thick ZnO rods is attributed to insufficient oxygen supply during the growth process with fixed oxygen flow rate.

  17. Highly efficient organic light emitting diodes formed by solution processed red emitters with evaporated blue common layer structure

    NASA Astrophysics Data System (ADS)

    Cho, Ye Ram; Kim, Hyung Suk; Yu, Young-Jun; Suh, Min Chul

    2015-10-01

    We prepared highly-efficient solution-processed red phosphorescent organic light emitting diodes (PHOLEDs) with a blue common layer structure that can reasonably confine the triplet excitons inside of the red emission layer (EML) with the assistance of a bipolar exciton blocking layer. The red PHOLEDs containing EML with a 7 : 3 ratio of 11-(4,6-diphenyl-[1,3,5]triazin-2-yl)-12-phenyl-11,12-dihydro-11,12-diaza-indeno[2,1-a]fluorene (n-type host, NH) : 4-(3-(triphenylen-2-yl)phenyl)dibenzo[b,d]thiophene (p-type host, PH) doped with 5% Iridium(III) bis(2-(3,5-dimethylphenyl)quinolinato-N,C2’)tetramethylheptadionate (Red Dopant, RD) produced the highest current and power efficiencies at 23.4 cd/A and 13.6 lm/W, with a 19% external quantum efficiency at 1000 cd/m2. To the best of our knowledge, such efficiency was the best among those that have been obtained from solution-processed small molecular red PHOLEDs. In addition, the host molecules utilized in this study have no flexible spacers, such as an alkyl chain, which normally deteriorate the stability of the device.

  18. Highly efficient organic light emitting diodes formed by solution processed red emitters with evaporated blue common layer structure

    PubMed Central

    Cho, Ye Ram; Kim, Hyung Suk; Yu, Young-Jun; Suh, Min Chul

    2015-01-01

    We prepared highly-efficient solution-processed red phosphorescent organic light emitting diodes (PHOLEDs) with a blue common layer structure that can reasonably confine the triplet excitons inside of the red emission layer (EML) with the assistance of a bipolar exciton blocking layer. The red PHOLEDs containing EML with a 7 : 3 ratio of 11-(4,6-diphenyl-[1,3,5]triazin-2-yl)-12-phenyl-11,12-dihydro-11,12-diaza-indeno[2,1-a]fluorene (n-type host, NH) : 4-(3-(triphenylen-2-yl)phenyl)dibenzo[b,d]thiophene (p-type host, PH) doped with 5% Iridium(III) bis(2-(3,5-dimethylphenyl)quinolinato-N,C2’)tetramethylheptadionate (Red Dopant, RD) produced the highest current and power efficiencies at 23.4 cd/A and 13.6 lm/W, with a 19% external quantum efficiency at 1000 cd/m2. To the best of our knowledge, such efficiency was the best among those that have been obtained from solution-processed small molecular red PHOLEDs. In addition, the host molecules utilized in this study have no flexible spacers, such as an alkyl chain, which normally deteriorate the stability of the device. PMID:26514274

  19. Highly efficient organic light emitting diodes formed by solution processed red emitters with evaporated blue common layer structure.

    PubMed

    Cho, Ye Ram; Kim, Hyung Suk; Yu, Young-Jun; Suh, Min Chul

    2015-01-01

    We prepared highly-efficient solution-processed red phosphorescent organic light emitting diodes (PHOLEDs) with a blue common layer structure that can reasonably confine the triplet excitons inside of the red emission layer (EML) with the assistance of a bipolar exciton blocking layer. The red PHOLEDs containing EML with a 7 : 3 ratio of 11-(4,6-diphenyl-[1,3,5]triazin-2-yl)-12-phenyl-11,12-dihydro-11,12-diaza-indeno[2,1-a]fluorene (n-type host, NH) : 4-(3-(triphenylen-2-yl)phenyl)dibenzo[b,d]thiophene (p-type host, PH) doped with 5% Iridium(III) bis(2-(3,5-dimethylphenyl)quinolinato-N,C2')tetramethylheptadionate (Red Dopant, RD) produced the highest current and power efficiencies at 23.4 cd/A and 13.6 lm/W, with a 19% external quantum efficiency at 1000 cd/m(2). To the best of our knowledge, such efficiency was the best among those that have been obtained from solution-processed small molecular red PHOLEDs. In addition, the host molecules utilized in this study have no flexible spacers, such as an alkyl chain, which normally deteriorate the stability of the device. PMID:26514274

  20. Rate of runaway evaporative cooling

    SciTech Connect

    Groep, J. van de; Straten, P. van der; Vogels, J. M.

    2011-09-15

    Evaporative cooling is a process that is essential in creating Bose-Einstein condensates in dilute atomic gasses. This process has often been simulated based on a model using a truncated Boltzmann distribution. This model assumes that the energy distribution up to the threshold energy can still be described by a Boltzmann distribution: it assumes detailed balance up to the threshold energy. However, the evolution of the distribution function in time is not taken into account. Here we solve the kinetic Boltzmann equation for a gas undergoing evaporative cooling in a harmonic and linear trap in order to determine the evolution of the energy distribution. The magnitude of the discrepancy with the truncated Boltzmannmodel is calculated by including a polynomial expansion of the distribution function. We find that up to 35% fewer particles are found in the high-energy tail of the distribution with respect to the truncated Boltzmann distribution and up to 15% more collisions are needed to reach quantum degeneracy. Supported by a detailed investigation of the particle loss rate at different energies, we conclude that the limited occupation of high-energy states during the evaporation process causes the lowering of the evaporation speed and efficiency.

  1. Laboratory prototype flash evaporator

    NASA Technical Reports Server (NTRS)

    Gaddis, J. L.

    1972-01-01

    A laboratory prototype flash evaporator that is being developed as a candidate for the space shuttle environmental control system expendable heat sink is described. The single evaporator configuration uses water as an evaporant to accommodate reentry and on-orbit peak heat loads, and Freon 22 for terrestrial flight phases below 120,000 feet altitude. The design features, fabrication techniques used for the prototype unit, redundancy considerations, and the fluid temperature control arrangement are reported in detail. The results of an extensive test program to determine the evaporator operational characteristics under a wide variety of conditions are presented.

  2. Isotope fractionation of water during evaporation without condensation.

    PubMed

    Cappa, Christopher D; Drisdell, Walter S; Smith, Jared D; Saykally, Richard J; Cohen, Ronald C

    2005-12-29

    The microscopic events engendering liquid water evaporation have received much attention over the last century, but remain incompletely understood. We present measurements of isotope fractionation occurring during free molecular evaporation from liquid microjets and show that the isotope ratios of evaporating molecules exhibit dramatic differences from equilibrium vapor values, strong variations with the solution deuterium mole fraction, and a clear temperature dependence. These results indicate the existence of an energetic barrier to evaporation and that the evaporation coefficient of water is less than unity. These new insights into water evaporation promise to advance our understanding of the processes that control the formation and lifetime of clouds in the atmosphere. PMID:16375440

  3. Biological activity during co-composting of sludge issued from the OMW evaporation ponds with poultry manure-Physico-chemical characterization of the processed organic matter.

    PubMed

    Hachicha, Salma; Sellami, Fatma; Cegarra, Juan; Hachicha, Ridha; Drira, Noureddine; Medhioub, Khaled; Ammar, Emna

    2009-02-15

    Olive mill sludge (OMS), a by-product resulting from natural evaporation of olive oil processing effluent, poses a major environmental threat. A current cost-effective practice of OMS management is composting. A mixture of OMS (60%) with poultry manure (PM) was successfully composted for 210 days. During the process, effluents of olive oil mill and confectionary were used to keep moisture at optimal level (40-60%). Biological indicators reflecting stability of the compost (microbial biota respiration and enumeration, and germination index) were analysed for the assessment of the product quality. The composted mixture showed a high microbial activity with a succession of microbial populations depending on the temperature reached during the biodegradation. The pathogen content from PM decreased with composting as did phytotoxic compounds. Phenols and lipids were reduced, respectively, by 40% and 84% while germination index increased with composting progress. Fourier transform infrared (FTIR) spectroscopic analysis revealed that the final compost improved the aromatic content compared to the starting materials, with a decrease in aliphatic groups and a reduction in the easily assimilated components by the microflora acting during the biological process. The final compost was characterized by relatively high organic matter content (26.21%), a low C/N ratio (16.21), an alkaline pH (8.32), a relatively high electrical conductivity (9.21mS/cm) and a high level of nutrients. The germination index for Lepidium sativum L. was 87.71% after 210 days of composting, showing that the final compost was not phytotoxic. PMID:18597932

  4. Measure Guideline: Evaporative Condensers

    SciTech Connect

    German, A; Dakin, B.; Hoeschele, M.

    2012-03-01

    This measure guideline on evaporative condensers provides information on properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices.

  5. Evaporation, Boiling and Bubbles

    ERIC Educational Resources Information Center

    Goodwin, Alan

    2012-01-01

    Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…

  6. High level waste storage tank farms/242-A evaporator standards/requirements identification document phase 1 assessment corrective actions/compliance schedule approval report

    SciTech Connect

    Biebesheimer, E.

    1996-09-30

    This document, the Standards/Requirements Identification Document (S/RID) Phase I Assessment Corrective Actions/Compliance Schedule Approval Report for the subject facility, contains the corrective actions required to bring the facility into compliance as a result of an Administrative Assessment to determine whether S/RID requirements are fully addressed by existing policies, plans or procedures. These actions are delineated in the Compliance Schedule Approvals which also contain; noncompliances, risks, compensatory measures, schedules for corrective actions, justifications for approval, and resource impacts.

  7. Evaporative Cooling Membrane Device

    NASA Technical Reports Server (NTRS)

    Lomax, Curtis (Inventor); Moskito, John (Inventor)

    1999-01-01

    An evaporative cooling membrane device is disclosed having a flat or pleated plate housing with an enclosed bottom and an exposed top that is covered with at least one sheet of hydrophobic porous material having a thin thickness so as to serve as a membrane. The hydrophobic porous material has pores with predetermined dimensions so as to resist any fluid in its liquid state from passing therethrough but to allow passage of the fluid in its vapor state, thereby, causing the evaporation of the fluid and the cooling of the remaining fluid. The fluid has a predetermined flow rate. The evaporative cooling membrane device has a channel which is sized in cooperation with the predetermined flow rate of the fluid so as to produce laminar flow therein. The evaporative cooling membrane device provides for the convenient control of the evaporation rates of the circulating fluid by adjusting the flow rates of the laminar flowing fluid.

  8. Combined effects of underlying substrate and evaporative cooling on the evaporation of sessile liquid droplets.

    PubMed

    Wang, Yilin; Ma, Liran; Xu, Xuefeng; Luo, Jianbin

    2015-07-28

    The evaporation of pinned, sessile droplets resting on finite thickness substrates was investigated numerically by extending the combined field approach to include the thermal properties of the substrate. By this approach, the combined effects of the underlying substrate and the evaporative cooling were characterized. The results show that the influence of the substrate on the droplet evaporation depends largely on the strength of the evaporative cooling. When the evaporative cooling is weak, the influence of substrate is also weak. As the strength of evaporative cooling increases, the influence of the substrate becomes more and more pronounced. Further analyses indicated that it is the cooling at the droplet surface and the temperature dependence of the saturation vapor concentration that relate the droplet evaporation to the underlying substrate. This indicates that the evaporative cooling number, Ec, can be used to identify the influence of the substrate on the droplet evaporation. The theoretical predictions by the present model are compared and found to be in good agreement with the experimental measurements. The present work may contribute to the body of knowledge concerning droplet evaporation and may have applications in a wide range of industrial and scientific processes. PMID:26059590

  9. Evaporative winds in X-ray binaries

    NASA Technical Reports Server (NTRS)

    Basko, M. M.; Suniaev, R. A.; Hatchett, S.; Mccray, R.

    1977-01-01

    Evaporation of gas from the surface of HZ Her by Her X-1 and its implications regarding the mass transfer process are examined further. The powerful soft X-ray flux results in an evaporation rate greater than previous estimates. The evaporative flow is shown to be subsonic at first, with the result that the capture of evaporated gas by Her X-1 may be efficient, and the self-excited wind mechanism is possible. A criterion for stabilization of mass transfer by stellar wind mass loss is derived. Possible mechanisms for the long-period variability of HZ Her are discussed. Evaporative winds are also estimated for Sco X-1 and Cyg X-2 spectra.

  10. Drop evaporation and triple line dynamics

    NASA Astrophysics Data System (ADS)

    Sobac, Benjamin; Brutin, David; Gavillet, Jerome; Université de Provence Team; Cea Liten Team

    2011-03-01

    Sessile drop evaporation is a phenomenon commonly came across in nature or in industry with cooling, paintings or DNA mapping. However, the evaporation of a drop deposited on a substrate is not completely understood due to the complexity of the problem. Here we investigate, with several nano-coating of the substrate (PTFE, SiOx, SiOc and CF), the influence of the dynamic of the triple line on the evaporation process. The experiment consists in analyzing simultaneously the motion of the triple line, the kinetics of evaporation, the internal thermal motion and the heat and mass transfer. Measurements of temperature, heat-flux and visualizations with visible and infrared cameras are performed. The dynamics of the evaporative heat flux appears clearly different depending of the motion of the triple line

  11. New Directions for Evaporative Cooling Systems.

    ERIC Educational Resources Information Center

    Robison, Rita

    1981-01-01

    New energy saving technology can be applied to older cooling towers; in addition, evaporative chilling, a process that links a cooling tower to the chilling equipment, can reduce energy use by 80 percent. (Author/MLF)

  12. Effects of the local structure dependence of evaporation fields on field evaporation behavior

    SciTech Connect

    Yao, Lan; Marquis, Emmanuelle A.; Withrow, Travis; Restrepo, Oscar D.; Windl, Wolfgang

    2015-12-14

    Accurate three dimensional reconstructions of atomic positions and full quantification of the information contained in atom probe microscopy data rely on understanding the physical processes taking place during field evaporation of atoms from needle-shaped specimens. However, the modeling framework for atom probe microscopy has only limited quantitative justification. Building on the continuum field models previously developed, we introduce a more physical approach with the selection of evaporation events based on density functional theory calculations. This model reproduces key features observed experimentally in terms of sequence of evaporation, evaporation maps, and depth resolution, and provides insights into the physical limit for spatial resolution.

  13. Rapid Evaporation of microbubbles

    NASA Astrophysics Data System (ADS)

    Gautam, Jitendra; Esmaeeli, Asghar

    2008-11-01

    When a liquid is heated to a temperature far above its boiling point, it evaporates abruptly. Boiling of liquid at high temperatures can be explosive and destructive, and poses a potential hazard for a host of industrial processes. Explosive boiling may occur if a cold and volatile liquid is brought into contact with a hot and non-volatile liquid, or if a liquid is superheated or depressurized rapidly. Such possibilities are realized, for example, in the depressurization of low boiling point liquefied natural gas (LNG) in the pipelines or storage tanks as a result of a leak. While boiling of highly heated liquids can be destructive at macroscale, the (nearly) instantaneous pace of the process and the release of large amount of kinetic energy make the phenomena extremely attractive at microscale where it is possible to utilize the released energy to derive micromechanical systems. For instance, there is currently a growing interest in micro-explosion of liquid for generation of micro bubbles for actuation purposes. The aim of the current study is to gain a fundamental understanding of the subject using direct numerical simulations. In particular, we seek to investigate the boundary between stable and unstable nucleus growth in terms of the degree of liquid superheat and to compare the dynamics of unstable and stable growth.

  14. Isothermal evaporation process simulation using the Pitzer model for the Quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K

    DOE PAGESBeta

    Meng, Lingzong; Gruszkiewicz, Miroslaw S.; Deng, Tianlong; Guo, Yafei; Li, Dan

    2015-08-05

    In this study, the Pitzer thermodynamic model for solid-liquid equilibria in the quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K was constructed by selecting the proper parameters for the subsystems in the literature. The solubility data of the systems NaCl–SrCl2–H2O, KCl–SrCl2–H2O, LiCl–SrCl2–H2O, and NaCl–KCl–SrCl2–H2O were used to evaluate the model. Good agreement between the experimental and calculated solubilities shows that the model is reliable. The Pitzer model for the quinary system at 298.15 K was then used to calculate the component solubilities and conduct computer simulation of isothermal evaporation of the mother liquor for the oilfield brine from Nanyishan district in themore » Qaidam Basin. The evaporation-crystallization path and sequence of salt precipitation, change in concentration and precipitation of lithium, sodium, potassium, and strontium, and water activities during the evaporation process were demonstrated. The salts precipitated from the brine in the order : KCl, NaCl, SrCl2∙6H2O, SrCl2∙2H2O, and LiCl∙H2O. The entire evaporation process may be divided into six stages. In each stage the variation trends for the relationships between ion concentrations or water activities and the evaporation ratio are different. This result of the simulation of brines can be used as a theoretical reference for comprehensive exploitation and utilization of this type of brine resources.« less

  15. Isothermal evaporation process simulation using the Pitzer model for the Quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K

    SciTech Connect

    Meng, Lingzong; Gruszkiewicz, Miroslaw S.; Deng, Tianlong; Guo, Yafei; Li, Dan

    2015-08-05

    In this study, the Pitzer thermodynamic model for solid-liquid equilibria in the quinary system LiCl–NaCl–KCl–SrCl2–H2O at 298.15 K was constructed by selecting the proper parameters for the subsystems in the literature. The solubility data of the systems NaCl–SrCl2–H2O, KCl–SrCl2–H2O, LiCl–SrCl2–H2O, and NaCl–KCl–SrCl2–H2O were used to evaluate the model. Good agreement between the experimental and calculated solubilities shows that the model is reliable. The Pitzer model for the quinary system at 298.15 K was then used to calculate the component solubilities and conduct computer simulation of isothermal evaporation of the mother liquor for the oilfield brine from Nanyishan district in the Qaidam Basin. The evaporation-crystallization path and sequence of salt precipitation, change in concentration and precipitation of lithium, sodium, potassium, and strontium, and water activities during the evaporation process were demonstrated. The salts precipitated from the brine in the order : KCl, NaCl, SrCl2∙6H2O, SrCl2∙2H2O, and LiCl∙H2O. The entire evaporation process may be divided into six stages. In each stage the variation trends for the relationships between ion concentrations or water activities and the evaporation ratio are different. This result of the simulation of brines can be used as a theoretical reference for comprehensive exploitation and utilization of this type of brine resources.

  16. Flash evaporator systems test

    NASA Technical Reports Server (NTRS)

    Dietz, J. B.

    1976-01-01

    A flash evaporator heat rejection system representative of that proposed for the space shuttle orbiter underwent extensive system testing at the NASA Johnson Space Center (JSC) to determine its operational suitability and to establish system performance/operational characteristics for use in the shuttle system. During the tests the evaporator system demonstrated its suitability to meet the shuttle requirements by: (1) efficient operation with 90 to 95% water evaporation efficiency, (2) control of outlet temperature to 40 + or - 2 F for partial heat load operation, (3) stability of control system for rapid changes in Freon inlet temperature, and (4) repeated dormant-to-active device operation without any startup procedures.

  17. Does groundwater enhance evaporative cooling?

    NASA Astrophysics Data System (ADS)

    Rouholahnejad, E.

    2015-12-01

    Evaporation is a key process in land-climate interactions, not only because it directly regulates the hydrological cycle, but also because it contributes to the Earth's energy balance. Due to its feedbacks on large-scale water processes and its impact on the dynamics of the atmosphere, it has been considered as a driver of droughts and heatwaves1-3. While evaporation from ocean surfaces is likely to increase with rising temperatures, it is unclear whether evapotranspiration from land surfaces could similarly increase, due to possible limitations imposed by soil moisture and vegetation physiology4. Observations suggest that groundwater (hereafter GW) has an important role in hydrological budgets and soil moisture variability in many regions, supplying moisture for evapotranspiration during dry seasons5, 6. Although modeling studies suggest that GW is often close enough to the surface to interact with the atmosphere7, 8, the soil water storage is often underestimated by land surface models. This is most likely due to neglecting the lateral movement of water from topographically higher altitudes to valley bottoms and its convergence close to the land surface, as well as the upward movement of water in the capillary fringe.The focus of this study is to understand where and when GW may significantly enhance the availability of soil water for evapotranspiration. We also quantified the potential contribution of GW to evapotranspiration in the areas where GW is a major supply. We used the global network of eddy covariance observations9 (FLUXNET) along with global modeled GW depth10 and GLEAM ET model estimates11 to address the current gap in modelling ET due to neglecting GW supply. Having identified areas where GW is tightly coupled with the atmosphere through evaporation processes, the study provides the basis to examine the "air conditioning effect" of GW and test the idea if GW enhances evaporation to the extent that leads to a cooler temperatures and wetter climates.

  18. Mixed feed evaporator

    DOEpatents

    Vakil, Himanshu B.; Kosky, Philip G.

    1982-01-01

    In the preparation of the gaseous reactant feed to undergo a chemical reaction requiring the presence of steam, the efficiency of overall power utilization is improved by premixing the gaseous reactant feed with water and then heating to evaporate the water in the presence of the gaseous reactant feed, the heating fluid utilized being at a temperature below the boiling point of water at the pressure in the volume where the evaporation occurs.

  19. Controlling interfacial curvature in nanoporous silica films formed by evaporation-induced self-assembly from nonionic surfactants. II. Effect of processing parameters on film structure.

    PubMed

    Urade, Vikrant N; Bollmann, Luis; Kowalski, Jonathan D; Tate, Michael P; Hillhouse, Hugh W

    2007-04-10

    The double-gyroid phase of nanoporous silica films has been shown to possess facile mass-transport properties and may be used as a mold to fabricate a variety of highly ordered inverse double-gyroid metal and semiconductor films. This phase exists only over a very small region of the binary phase diagram for most surfactants, and it has been very difficult to synthesize metal oxide films with this structure by evaporation-induced self-assembly (EISA). Here, we show the interplay of the key parameters needed to synthesize these structures reproducibly and show that the interfacial curvature may be systematically controlled. Grazing angle of incidence small-angle X-ray scattering (GISAXS) is used to determine the structure and orientation of nanostructured silica films formed by EISA from dilute silica/(poly(ethylene oxide)-b-poly(propylene oxide)-b-alkyl) surfactant solutions. Four different highly ordered film structures are observed by changing only the concentration of the surfactant, the relative humidity during dip-coating, and the aging time of the solution prior to coating. The highly ordered films progress from rhombohedral (Rm) to 2D rectangular (c2m) to double-gyroid (distorted Iad) to lamellar systematically as interfacial curvature decreases. Under all experimental conditions investigated, increasing the aging time of the coating solution was found to decrease the interfacial curvature. In particular, this parameter was critical to being able to synthesize highly ordered, pure-phase double-gyroid films. The key role of the aging time is shown via processing diagrams that map out the interplay between the aging time, composition, and relative humidity. 29Si nuclear magnetic resonance (NMR) spectroscopy and solution-phase small-angle X-ray scattering (SAXS) of the aged coating solutions presented in part I of this series are then used to interpret the effects of aging prior to dip-coating. Specifically, it was found that a predictive model based on volume

  20. Saline Evaporation from Porous Media: Characteristics of Salt Precipitation and Its Effect on Evaporation

    NASA Astrophysics Data System (ADS)

    Nachshon, U.; Weisbrod, N.; Dragila, M. I.; Grader, A. S.

    2010-12-01

    Salt precipitation as subflorescence or efflorescence crust occurs during saline solutions evaporation from porous media. Non-linear synergy between evaporation and salt precipitation processes results in a complex mechanism that has yet to be quantitatively understood. Presented here is a series of experiments and a mathematical model that shed light on these processes. Experiments include: (1) long-term column evaporation experiments to quantify changes in evaporation rates due to salt precipitation; (2) long-term Hele-Shaw evaporation experiments to visualize salt precipitation at the macro scale; and (3) CT scans of evaporated porous media pre-saturated with NaI solutions to observe salt precipitation at the pore scale. Experiments were conducted for homogeneous and heterogeneous media using a number of saline solutions (NaCl, CaSO4, KCl, CuSO4 and NaI). A mathematical model was developed to explore quantitatively the physical and chemical mechanisms involved in the evaporation-salt precipitation process. The model simulated salt precipitation and it affect on evaporation. Three new stages of evaporation are introduced and defined for saline solutions: SS1, SS2 and SS3. SS1 exhibits a low and gradual decrease in evaporation rate caused by a changing osmotic potential. During SS2, evaporation rate falls precipitously a salt precipitates. SS3 is characterized by a constant, low evaporation rate. The phenomenological similarity to the classical evaporation stages of pure water, S1, S2 and S3, are only coincidental, the three saline stages correspond to entirely different mechanisms. The mathematical model was used to also quantify the diffusion coefficient through a salt crust. Heterogeneity during saline evaporation was found to strongly control the location of salt precipitation: salt precipitation occurred mainly within the fine-pore regions which act as a wick transporting water from the coarser media. Heterogeneity also permits greater saline evaporation by

  1. Evaporation of an atomic beam on a material surface

    SciTech Connect

    Reinaudi, G.; Lahaye, T.; Couvert, A.; Wang, Z.; Guery-Odelin, D.

    2006-03-15

    We report on the implementation of evaporative cooling of a magnetically guided beam by adsorption on a ceramic surface. We use a transverse magnetic field to shift locally the beam towards the surface, where atoms are selectively evaporated. With a 5-mm-long ceramic piece, we gain a factor of 1.5{+-}0.2 on the phase-space density. Our results are consistent with a 100% efficiency of this evaporation process. The flexible implementation that we have demonstrated, combined with the very local action of the evaporation zone, makes this method particularly suited for the evaporative cooling of a beam.

  2. Optimized Bose-Einstein-condensate production in a dipole trap based on a 1070-nm multifrequency laser: Influence of enhanced two-body loss on the evaporation process

    SciTech Connect

    Lauber, T.; Kueber, J.; Wille, O.; Birkl, G.

    2011-10-15

    We present an optimized strategy for the production of tightly confined Bose-Einstein condensates (BEC) of {sup 87}Rb in a crossed dipole trap with direct loading from a magneto-optical trap. The dipole trap is created with light of a multifrequency fiber laser with a center wavelength of 1070 nm. Evaporative cooling is performed by ramping down the laser power only. A comparison of the resulting atom number in an almost pure BEC to the initial atom number and the value for the gain in phase space density per atom lost confirm that this straightforward strategy is very efficient. We observe that the temporal characteristics of evaporation sequence are strongly influenced by power-dependent two-body losses resulting from enhanced optical pumping to the higher-energy hyperfine state. We characterize these losses and compare them to results obtained with a single-frequency laser at 1030 nm.

  3. Optimized Bose-Einstein-condensate production in a dipole trap based on a 1070-nm multifrequency laser: Influence of enhanced two-body loss on the evaporation process

    NASA Astrophysics Data System (ADS)

    Lauber, T.; Küber, J.; Wille, O.; Birkl, G.

    2011-10-01

    We present an optimized strategy for the production of tightly confined Bose-Einstein condensates (BEC) of 87Rb in a crossed dipole trap with direct loading from a magneto-optical trap. The dipole trap is created with light of a multifrequency fiber laser with a center wavelength of 1070 nm. Evaporative cooling is performed by ramping down the laser power only. A comparison of the resulting atom number in an almost pure BEC to the initial atom number and the value for the gain in phase space density per atom lost confirm that this straightforward strategy is very efficient. We observe that the temporal characteristics of evaporation sequence are strongly influenced by power-dependent two-body losses resulting from enhanced optical pumping to the higher-energy hyperfine state. We characterize these losses and compare them to results obtained with a single-frequency laser at 1030 nm.

  4. Evaporation drift of pesticides active ingredients.

    PubMed

    De Schampheleire, M; Nuyttens, D; De Keyser, D; Spanoghe, P

    2008-01-01

    Losses of pesticide active ingredients (a.i.) into the atmosphere can occur through several pathways. A main pathway is evaporation drift. The evaporation process of pesticide a.i., after application, is affected by three main factors: Physicochemical properties of the pesticide a.i., weather conditions and crop structure. The main physicochemical parameters are the Henry coefficient, which is a measure for the volatilization tendency of the pesticide a.i. from a dilute aqueous solution, and the vapour pressure, which is a measure for the volatilization tendency of the pesticide a.i. from the solid phase. Five pesticide a.i., with various Henry coefficients and various vapour pressures, were selected to conduct laboratory experiments: metalaxyl-m, dichlorovos, diazinon, Lindane and trifluralin. Evaporation experiments were conducted in a volatilization chamber. It was found that the evaporation tendencies significantly differed according to the physicochemical properties of the a.i. PMID:19226822

  5. Evaporation of petroleum products from contaminated soils

    SciTech Connect

    Kang, S.H.; Oulman, C.S.

    1996-05-01

    Bioremediation can remove petroleum products from soil that has been contaminated by leaking underground storage tanks, but abiotic processes such as evaporation can contribute significantly to the overall removal process. The mathematical model described in this paper was developed to predict the evaporation rate of volatile liquids from petroleum-contaminated sand. The model is based on simple concepts relating to molecular diffusion embodied in the theory underlying the estimation of binary diffusivities using measurements made with an Arnold diffusion cell. The model in its simplified form indicates that the rate of evaporation for a particular volatile liquid is proportional to the square root of the product of diffusivity and partial pressure divided by the molecular weight of the liquid. This in part explains why evaporative losses from sand are so much higher for gasoline than for diesel fuel. The model also shows that the time for evaporation is directly proportional to the square of the depth dried out and inversely proportional to the vapor pressure of the volatile liquid. The model was tested using gravimetric measurements of the evaporation of n-heptane, unleaded gasoline, and diesel fuel from sand under laboratory conditions.

  6. Hot air drum evaporator

    DOEpatents

    Black, Roger L.

    1981-01-01

    An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

  7. Waste Feed Evaporation Physical Properties Modeling

    SciTech Connect

    Daniel, W.E.

    2003-08-25

    This document describes the waste feed evaporator modeling work done in the Waste Feed Evaporation and Physical Properties Modeling test specification and in support of the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) project. A private database (ZEOLITE) was developed and used in this work in order to include the behavior of aluminosilicates such a NAS-gel in the OLI/ESP simulations, in addition to the development of the mathematical models. Mathematical models were developed that describe certain physical properties in the Hanford RPP-WTP waste feed evaporator process (FEP). In particular, models were developed for the feed stream to the first ultra-filtration step characterizing its heat capacity, thermal conductivity, and viscosity, as well as the density of the evaporator contents. The scope of the task was expanded to include the volume reduction factor across the waste feed evaporator (total evaporator feed volume/evaporator bottoms volume). All the physical properties were modeled as functions of the waste feed composition, temperature, and the high level waste recycle volumetric flow rate relative to that of the waste feed. The goal for the mathematical models was to predict the physical property to predicted simulation value. The simulation model approximating the FEP process used to develop the correlations was relatively complex, and not possible to duplicate within the scope of the bench scale evaporation experiments. Therefore, simulants were made of 13 design points (a subset of the points used in the model fits) using the compositions of the ultra-filtration feed streams as predicted by the simulation model. The chemistry and physical properties of the supernate (the modeled stream) as predicted by the simulation were compared with the analytical results of experimental simulant work as a method of validating the simulation software.

  8. Evaporation of Ethanol-Water Binary Mixture Sessile Liquid Marbles.

    PubMed

    Ooi, Chin Hong; Bormashenko, Edward; Nguyen, Anh V; Evans, Geoffrey M; Dao, Dzung V; Nguyen, Nam-Trung

    2016-06-21

    Liquid marble is a liquid droplet coated with particles. Recently, the evaporation process of a sessile liquid marble using geometric measurements has attracted great attention from the research community. However, the lack of gravimetric measurement limits further insights into the physical changes of a liquid marble during the evaporation process. Moreover, the evaporation process of a marble containing a liquid binary mixture has not been reported before. The present paper investigates the effective density and the effective surface tension of an evaporating liquid marble that contains aqueous ethanol at relatively low concentrations. The effective density of an evaporating liquid marble is determined from the concurrent measurement of instantaneous mass and volume. Density measurements combined with surface profile fitting provide the effective surface tension of the marble. We found that the density and surface tension of an evaporating marble are significantly affected by the particle coating. PMID:27230102

  9. Organic Evaporator steam valve failure

    SciTech Connect

    Jacobs, R. A.

    1992-09-29

    DWPF Technical has requested an analysis of the capacity of the organic Evaporator (OE) condenser (OEC) be performed to determine its capability in the case where the OE steam flow control valve fails open. Calculations of the OE boilup and the OEC heat transfer coefficient indicate the OEC will have more than enough capacity to remove the heat at maximum OE boilup. In fact, the Salt Cell Vent Condenser (SCVC) should also have sufficient capacity to handle the maximum OE boilup. Therefore it would require simultaneous loss of OEC and/or SCVC condensing capacity for the steam valve failure to cause high benzene in the Process Vessel Vent System (PVVS).

  10. Droplet evaporation on a soluble substrate

    NASA Astrophysics Data System (ADS)

    Mailleur, Alexandra; Pirat, Christophe; Colombani, Jean; CNES Collaboration

    2015-11-01

    Stains left by evaporated droplets are ubiquitous in everyday life as well as in industrial processes. Whatever the composition of the evaporating liquid (colloidal suspensions, biological fluids...), the stains are mostly constituted by a deposit at the periphery of the dried drop, similar to a coffee stain (Deegan, 1997). All these studies have been carried with non-reacting solids. In this presentation, we focus on the behavior of a pure-water droplet evaporating on a soluble substrate which is more complex, since three phenomena are strongly interacting: the dissolution of the substrate, the diffusion/convection of the dissolved species into the drop and the evaporation of the liquid. NaCl and KCl single crystals have been chosen for this experimental study as they are fast-dissolving solids. We have observed that the dissolution induces a pinning of the triple line from the beginning of the evaporation, leading to a decrease of the contact angle in time. At the end of the evaporation, a peripheral deposit is always formed, proof of an outward flow inside the drop (coffee-ring effect). The authors would like to thank the CNES for the financial support.

  11. Infrared thermography of dropwise evaporative cooling

    NASA Astrophysics Data System (ADS)

    Klassen, Michael; di Marzo, Marino; Sirkis, James

    1992-01-01

    An infrared thermographic technique is developed to obtain the transient solid surface temperature distribution in the neighborhood of an evaporating droplet. This technique is nonintrusive and is not affected by the time response of the measuring device (i.e., thermocouple). The entire surface is monitored at any instant of time, and information on the area influenced by the evaporative cooling process is easily derived. A detailed description of the image processing based data reduction is provided. A water droplet in the range of 10-50 microliter is deposited on an opaque glasslike material that has an initial surface temperature between 100 and 165 deg C. The evaporative cooling process is fully documented, and these new findings are contrasted with the published literature to gain a better understanding of the phenomena involved.

  12. Mobile evaporator corrosion test results

    SciTech Connect

    Rozeveld, A.; Chamberlain, D.B.

    1997-05-01

    Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80{degrees}C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either {open_quotes}satisfactory{close_quotes} (2-20 mpy) or {open_quotes}excellent{close_quotes} (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment.

  13. DWPF RECYCLE EVAPORATOR FLOWSHEET EVALUATION (U)

    SciTech Connect

    Stone, M

    2005-04-30

    The Defense Waste Processing Facility (DWPF) converts the high level waste slurries stored at the Savannah River Site into borosilicate glass for long-term storage. The vitrification process results in the generation of approximately five gallons of dilute recycle streams for each gallon of waste slurry vitrified. This dilute recycle stream is currently transferred to the H-area Tank Farm and amounts to approximately 1,400,000 gallons of effluent per year. Process changes to incorporate salt waste could increase the amount of effluent to approximately 2,900,000 gallons per year. The recycle consists of two major streams and four smaller streams. The first major recycle stream is condensate from the Chemical Process Cell (CPC), and is collected in the Slurry Mix Evaporator Condensate Tank (SMECT). The second major recycle stream is the melter offgas which is collected in the Off Gas Condensate Tank (OGCT). The four smaller streams are the sample flushes, sump flushes, decon solution, and High Efficiency Mist Eliminator (HEME) dissolution solution. These streams are collected in the Decontamination Waste Treatment Tank (DWTT) or the Recycle Collection Tank (RCT). All recycle streams are currently combined in the RCT and treated with sodium nitrite and sodium hydroxide prior to transfer to the tank farm. Tank Farm space limitations and previous outages in the 2H Evaporator system due to deposition of sodium alumino-silicates have led to evaluation of alternative methods of dealing with the DWPF recycle. One option identified for processing the recycle was a dedicated evaporator to concentrate the recycle stream to allow the solids to be recycled to the DWPF Sludge Receipt and Adjustment Tank (SRAT) and the condensate from this evaporation process to be sent and treated in the Effluent Treatment Plant (ETP). In order to meet process objectives, the recycle stream must be concentrated to 1/30th of the feed volume during the evaporation process. The concentrated stream

  14. Convective Evaporation Of Sprayed Liquid

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1987-01-01

    Theoretical model developed to analyze behavior of both dense and dilute clusters of evaporating liquid drops in gas flows. Particularly useful in search for methods of controlling evaporation, ignition, and combustion of fuel sprays.

  15. Putting the "vap" into evaporation

    NASA Astrophysics Data System (ADS)

    Shuttleworth, W. J.

    2007-01-01

    In the spirit of the Special Issue of HESS to which it contributes, this paper documents the origin and development of the science of natural evaporation from land surfaces over the last 30-35 years, since the symposium A View from the Watershed was held to commemorate the opening of the new Institute of Hydrology (IH) building in 1973. Important subsequent technical progress includes the ability to measure routinely the diurnal cycle of near-surface meteorological variables using automatic weather stations, and of surface energy and momentum exchanges using automated implementations of the Bowen Ratio/Energy Budget technique and the Eddy Correlation technique, along with the capability to estimate the "fetch" for which these measurements apply. These improvements have been complemented by new methods to measure the separate components of evaporation, including: the interception process using randomly relocated below-canopy gauges, transpiration fluxes from individual leaves/shoots using porometers and from plants/plant components using stem-flow gauges and soil evaporation using micro-lysimeters and soil moisture depletion methods. In recent years progress has been made in making theory-based area-average estimates of evaporation using scintillometers, and model-based area-average estimates by assembling many streams of relevant data into Land Data Assimilation Systems. Theoretical progress has been made in extending near-surface turbulence theory to accommodate the effect of the "excess" boundary layer resistance to leaf-to-air transfer of energy and mass fluxes relative to that for momentum, and to allow for observed shortcoming in stability factors in the transition layer immediately above vegetation. Controversy regarding the relative merits of multi-layer model and "big leaf" representations of whole-canopy exchanges has been resolved in favour of the latter approach. Important gaps in the theory of canopy-atmosphere interactions have been filled, including

  16. Evaporated VOx Thin Films

    NASA Astrophysics Data System (ADS)

    Stapinski, Tomasz; Leja, E.

    1989-03-01

    VOx thin films on glass were obtained by thermal evaporation of V205, powder. The structural investigations were carried out with the use of X-ray diffractometer. The electrical properties of the film were examined by means of temperature measurements of resistivity for the samples heat-treated in various conditions. Optical transmission and reflection spectra of VOX films of various composition showed the influence of the heat treatment.

  17. Falling film evaporator

    DOEpatents

    Bruns, Lester E.

    1976-01-01

    A falling film evaporator including a vertically oriented pipe heated exteriorly by a steam jacket and interiorly by a finned steam tube, all heating surfaces of the pipe and steam tube being formed of a material wet by water such as stainless steel, and packing within the pipe consisting of Raschig rings formed of a material that is not wet by water such as polyvinylidene fluoride.

  18. Vertical counterflow evaporative cooler

    DOEpatents

    Bourne, Richard C.; Lee, Brian Eric; Callaway, Duncan

    2005-01-25

    An evaporative heat exchanger having parallel plates that define alternating dry and wet passages. A water reservoir is located below the plates and is connected to a water distribution system. Water from the water distribution system flows through the wet passages and wets the surfaces of the plates that form the wet passages. Air flows through the dry passages, mixes with air below the plates, and flows into the wet passages before exiting through the top of the wet passages.

  19. Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Almlie, Jay C.

    2010-01-01

    A water membrane evaporator (WME) has been conceived and tested as an alternative to the contamination-sensitive and corrosion-prone evaporators currently used for dissipating heat from space vehicles. The WME consists mainly of the following components: An outer stainless-steel screen that provides structural support for the components mentioned next; Inside and in contact with the stainless-steel screen, a hydrophobic membrane that is permeable to water vapor; Inside and in contact with the hydrophobic membrane, a hydrophilic membrane that transports the liquid feedwater to the inner surface of the hydrophobic membrane; Inside and in contact with the hydrophilic membrane, an annular array of tubes through which flows the spacecraft coolant carrying the heat to be dissipated; and An inner exclusion tube that limits the volume of feedwater in the WME. In operation, a pressurized feedwater reservoir is connected to the volume between the exclusion tube and the coolant tubes. Feedwater fills the volume, saturates the hydrophilic membrane, and is retained by the hydrophobic membrane. The outside of the WME is exposed to space vacuum. Heat from the spacecraft coolant is conducted through the tube walls and the water-saturated hydrophilic membrane to the liquid/vapor interface at the hydrophobic membrane, causing water to evaporate to space. Makeup water flows into the hydrophilic membrane through gaps between the coolant tubes.

  20. Evaporative oxidation treatability test report

    SciTech Connect

    1995-04-01

    In 1992, Congress passed the Federal Facilities Compliance Act that requires the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with the Resource Conservation and Recovery Act (RCRA) land disposal restrictions (LDRs). In response to the need for mixed-waste treatment capacity where available off-site commercial treatment facilities do not exist or cannot be used, the DOE Albuquerque Operations Office (DOE-AL) organized a Treatment Selection Team to match mixed wastes with treatment options and develop a strategy for treatment of its mixed wastes. DOE-AL manages operations at nine sites with mixed-waste inventories. The Treatment Selection Team determined a need to develop mobile treatment capacity to treat wastes at the sites where the wastes are generated. Treatment processes used for mixed waste not only must address the hazardous component (i.e., meet LDRs) but also must contain the radioactive component in a form that allows final disposal while protecting workers, the public, and the environment. On the basis of recommendations of the Treatment Selection Team, DOE-AL assigned projects to the sites to bring mixed-waste treatment capacity on-line. The three technologies assigned to the DOE Grand Junction Projects Office (GJPO) are evaporative oxidation, thermal desorption, and treated wastewater evaporation. Rust Geotech, the DOE-GJPO prime contractor, was assigned to design and fabricate mobile treatment units (MTUs) for these three technologies and to deliver the MTUs to selected DOE-AL sites. To conduct treatability tests at the GJPO, Rust leased a pilot-scale evaporative oxidation unit from the Clemson Technical Center (CTC), Anderson, South Carolina. The purpose of this report is to document the findings and results of tests performed using this equipment.

  1. Low-Temperature Synthesis of Nanoparticles in the Process of Evaporation of Femtoliter Droplets of a Solution at a Low Pressure

    NASA Astrophysics Data System (ADS)

    Penyazkov, O. G.; Saverchenko, V. I.; Fisenko, S. P.

    2014-07-01

    Results of an X-ray phase analysis of the products of the low-temperature spray pyrolysis of femtoliter droplets of aqueous nickel-chloride solutions are presented. It is shown that the composition of the nanoparticles accumulated on the electrode-substrate in an aerosol reactor depends on the pressure in it and the initial supersaturation of the solution. It was established that marked chemical transformations of the indicated droplets begin at a pressure lower than 80 Torr. The influence of the evaporation of droplets from a solution and the nucleation in the supersaturated solution formed on the kinetics of the chemical transformations of these droplets, giving rise to the substances obtained in the experiments, is discussed.

  2. Surface tension of evaporating nanofluid droplets

    SciTech Connect

    Chen, Ruey-Hung; Phuoc, Tran X.; Martello, Donald

    2011-05-01

    Measurements of nanofluid surface tension were made using the pendant droplet method. Three different types of nanoparticles were used - laponite, silver and Fe2O3 - with de-ionized water (DW) as the base fluid. The reported results focus on the following categories; (1) because some nanoparticles require surfactants to form stable colloids, the individual effects of the surfactant and the particles were investigated; (2) due to evaporation of the pendant droplet, the particle concentration increases, affecting the apparent surface tension; (3) because of the evaporation process, a hysteresis was found where the evaporating droplet can only achieve lower values of surface tension than that of nanofluids at the same prepared concentrations: and (4) the Stefan equation relating the apparent surface tension and heat of evaporation was found to be inapplicable for nanofluids investigated. Comparisons with findings for sessile droplets are also discussed, pointing to additional effects of nanoparticles other than the non-equilibrium evaporation process.

  3. The continuous similarity model of bulk soil-water evaporation

    NASA Technical Reports Server (NTRS)

    Clapp, R. B.

    1983-01-01

    The continuous similarity model of evaporation is described. In it, evaporation is conceptualized as a two stage process. For an initially moist soil, evaporation is first climate limited, but later it becomes soil limited. During the latter stage, the evaporation rate is termed evaporability, and mathematically it is inversely proportional to the evaporation deficit. A functional approximation of the moisture distribution within the soil column is also included in the model. The model was tested using data from four experiments conducted near Phoenix, Arizona; and there was excellent agreement between the simulated and observed evaporation. The model also predicted the time of transition to the soil limited stage reasonably well. For one of the experiments, a third stage of evaporation, when vapor diffusion predominates, was observed. The occurrence of this stage was related to the decrease in moisture at the surface of the soil. The continuous similarity model does not account for vapor flow. The results show that climate, through the potential evaporation rate, has a strong influence on the time of transition to the soil limited stage. After this transition, however, bulk evaporation is independent of climate until the effects of vapor flow within the soil predominate.

  4. Normal evaporation of binary alloys

    NASA Technical Reports Server (NTRS)

    Li, C. H.

    1972-01-01

    In the study of normal evaporation, it is assumed that the evaporating alloy is homogeneous, that the vapor is instantly removed, and that the alloy follows Raoult's law. The differential equation of normal evaporation relating the evaporating time to the final solute concentration is given and solved for several important special cases. Uses of the derived equations are exemplified with a Ni-Al alloy and some binary iron alloys. The accuracy of the predicted results are checked by analyses of actual experimental data on Fe-Ni and Ni-Cr alloys evaporated at 1600 C, and also on the vacuum purification of beryllium. These analyses suggest that the normal evaporation equations presented here give satisfactory results that are accurate to within an order of magnitude of the correct values, even for some highly concentrated solutions. Limited diffusion and the resultant surface solute depletion or enrichment appear important in the extension of this normal evaporation approach.

  5. Hydrodynamic Instabilities Produced by Evaporation

    NASA Astrophysics Data System (ADS)

    Romo-Cruz, Julio Cesar Ruben; Hernandez-Zapata, Sergio; Ruiz-Chavarria, Gerardo

    2012-11-01

    When a liquid layer (alcohol in the present work) is in an environment where its relative humidity is less than 100 percent evaporation appears. When RH is above a certain threshold the liquid is at rest. If RH decreases below this threshold the flow becomes unstable, and hydrodynamic cells develop. The aim of this work is to understand the formation of those cells and its main features. Firstly, we investigate how the cell size depends on the layer width. We also study how temperature depends on the vertical coordinate when the cells are present. An inverse temperature gradient is found, that is, the bottom of liquid layer is colder than the free surface. This shows that the intuitive idea that the cells are due to a direct temperature gradient, following a Marangoni-like process, does not work. We propose the hypothesis that the evaporation produce a pressure gradient that is responsible of the cell development. On the other hand, using a Schlieren technique we study the topography of the free surface when cells are present. Finally the alcohol vapor layer adjacent to the liquid surface is explored using scattering experiments, giving some insight on the plausibility of the hypothesis described previously. Authors acknowledge support by DGAPA-UNAM under project IN116312 ``Vorticidad y ondas no lineales en fluidos.''

  6. Evaporative cooling of antiprotons for the production of trappable antihydrogen

    SciTech Connect

    Silveira, D. M.; Cesar, C. L.; Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Ashkezari, M. D.; Hayden, M. E.; Baquero-Ruiz, M.; Chapman, S.; Fajans, J.; Povilus, A.; So, C.; Wurtele, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Madsen, N.; Werf, D. P. van der; Friesen, T.; Hydomako, R.; and others

    2013-03-19

    We describe the implementation of evaporative cooling of charged particles in the ALPHA apparatus. Forced evaporation has been applied to cold samples of antiprotons held in Malmberg-Penning traps. Temperatures on the order of 10 K were obtained, while retaining a significant fraction of the initial number of particles. We have developed a model for the evaporation process based on simple rate equations and applied it succesfully to the experimental data. We have also observed radial re-distribution of the clouds following evaporation, explained by simple conservation laws. We discuss the relevance of this technique for the recent demonstration of magnetic trapping of antihydrogen.

  7. Clustered field evaporation of metallic glasses in atom probe tomography.

    PubMed

    Zemp, J; Gerstl, S S A; Löffler, J F; Schönfeld, B

    2016-03-01

    Field evaporation of metallic glasses is a stochastic process combined with spatially and temporally correlated events, which are referred to as clustered evaporation (CE). This phenomenon is investigated by studying the distance between consecutive detector hits. CE is found to be a strongly localized phenomenon (up to 3nm in range) which also depends on the type of evaporating ions. While a similar effect in crystals is attributed to the evaporation of crystalline layers, CE of metallic glasses presumably has a different - as yet unknown - physical origin. The present work provides new perspectives on quantification methods for atom probe tomography of metallic glasses. PMID:26724469

  8. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

    SciTech Connect

    Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Ashkezari, M. D.; Hayden, M. E.; Baquero-Ruiz, M.; Chapman, S.; Fajans, J.; Povilus, A.; So, C.; Wurtele, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A.; Madsen, N.; Werf, D. P. van der; Wilding, D.; Cesar, C. L.; Lambo, R.

    2010-07-02

    We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.

  9. Evaporative cooling of antiprotons to cryogenic temperatures.

    PubMed

    Andresen, G B; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A; Hydomako, R; Jonsell, S; Kurchaninov, L; Lambo, R; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wilding, D; Wurtele, J S; Yamazaki, Y

    2010-07-01

    We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal. PMID:20867439

  10. DWPF Recycle Evaporator Shielded Cells Testing

    SciTech Connect

    Fellinger, T. L.; Herman, D. T.; Stone, M.E

    2005-07-01

    Testing was performed to determine the feasibility and processing characteristics of evaporation of actual Defense Waste Processing Facility (DWPF) recycle material. Samples of the Off Gas Condensate Tank (OGCT) and Slurry Mix Evaporator Condensate Tank (SMECT) were transferred from DWPF to the Savannah River National Lab (SRNL) Shielded Cells and blended with De-Ionized (DI) water and a small amount of Slurry Mix Evaporator (SME) product. A total of 3000 mL of this feed was concentrated to approximately 90 mL during a semi-batch evaporation test of approximately 17 hours. One interruption occurred during the run when the feed tube developed a split and was replaced. Samples of the resulting condensate and concentrate were collected and analyzed. The resulting analysis of the condensate was compared to the Waste Acceptance Criteria (WAC) limits for the F/H Effluent Treatment Plant (ETP). Results from the test were compared to previous testing using simulants and OLI modeling. Conclusions from this work included the following: (1) The evaporation of DWPF recycle to achieve a 30X concentration factor was successfully demonstrated. The feed blend of OGCT and SMECT material was concentrated from 3000 mL to approximately 90 mL during testing, a concentration of approximately 33X. (2) Foaming was observed during the run. Dow Corning 2210 antifoam was added seven times throughout the run at 100 parts per million (ppm) per addition. The addition of this antifoam was very effective in reducing the foam level, but the impact diminished over time and additional antifoam was required every 2 to 3 hours during the run. (3) No scale or solids formed on the evaporator vessel, but splatter was observed in the headspace of the evaporator vessel. No scaling formed on the stainless steel thermocouple. (4) The majority of the analytes met the F/H ETP WAC. However, the detection limits for selected species (Sr-90, Pu-238, Pu-240, Am-243, and Cm-244) exceeded the ETP WAC limits. (5) I

  11. Method of evaporation

    NASA Technical Reports Server (NTRS)

    Dufresne, Eugene R.

    1987-01-01

    Liquids, such as juices, milk, molten metal and the like are concentrated by forming uniformly-sized, small droplets in a precision droplet forming assembly and deploying the droplets in free fall downwardly as a central column within an evacuated column with cool walls. A portion of the solvent evaporates. The vapor flows to the wall, condenses, and usually flows down the wall as a film to condensate collector and drain. The vertical column of freely falling droplets enters the splash guard. The condensate can be collected, sent to other towers or recycled.

  12. Sensible heat observations reveal soil-water evaporation dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water evaporation is important at scales ranging from microbial ecology to large-scale climate. Yet, routine measurments are unable to capture rapidly shifting near-surface soil heat and water processes involved in soil-water evaporation. The objective of this study was to determine the depth a...

  13. Reservoir evaporation in Texas, USA

    NASA Astrophysics Data System (ADS)

    Wurbs, Ralph A.; Ayala, Rolando A.

    2014-03-01

    The role of reservoir surface evaporation in river/reservoir water budgets and water management is explored using a modeling system that combines historical natural hydrology with current conditions of water resources development and management. The long-term mean evaporation from the 3415 reservoirs in the Texas water rights permit system is estimated to be 7.53 billion m3/year, which is equivalent to 61% of total agricultural or 126% of total municipal water use in the state during the year 2010. Evaporation varies with the hydrologic conditions governing reservoir surface areas and evaporation rates. Annual statewide total evaporation volumes associated with exceedance probabilities of 75%, 50%, and 25% are 7.07, 7.47, and 7.95 billion m3/year, respectively. Impacts of evaporation are greatest during extended severe droughts that govern water supply capabilities.

  14. Optimized evaporation technique for leachate treatment: Small scale implementation.

    PubMed

    Benyoucef, Fatima; Makan, Abdelhadi; El Ghmari, Abderrahman; Ouatmane, Aziz

    2016-04-01

    This paper introduces an optimized evaporation technique for leachate treatment. For this purpose and in order to study the feasibility and measure the effectiveness of the forced evaporation, three cuboidal steel tubs were designed and implemented. The first control-tub was installed at the ground level to monitor natural evaporation. Similarly, the second and the third tub, models under investigation, were installed respectively at the ground level (equipped-tub 1) and out of the ground level (equipped-tub 2), and provided with special equipment to accelerate the evaporation process. The obtained results showed that the evaporation rate at the equipped-tubs was much accelerated with respect to the control-tub. It was accelerated five times in the winter period, where the evaporation rate was increased from a value of 0.37 mm/day to reach a value of 1.50 mm/day. In the summer period, the evaporation rate was accelerated more than three times and it increased from a value of 3.06 mm/day to reach a value of 10.25 mm/day. Overall, the optimized evaporation technique can be applied effectively either under electric or solar energy supply, and will accelerate the evaporation rate from three to five times whatever the season temperature. PMID:26826455

  15. The properties of Co- and Fe-doped GDC for low-temperature processing of solid oxide fuel cell by electron-beam evaporation.

    PubMed

    Yang, Seon-Ho; Kim, Kyung-Hwan; Choi, Hyung-Wook

    2013-08-01

    This study is transition metal oxides (FeO and CoO) were added to Gd-doped ceria (Gd0.1Ce0.9O1.95, GDC) powder for preparing the thin-film electrolyte used in the Ni-GDC anode-supported intermediate temperature solid oxide fuel cell (SOFC). Recently much attention was aimed at successful powder preparation with high sinter activity and conductivity. However, one of the challenges in preparing the GDC electrolytes is the densification issue. It is difficult to achieve the densification of GDC below 1600 degrees C. To overcome this drawback, attentions of the research on the densification of the GDC electrolyte is paid more on changing of the fabrication technology, the powder properties, and the sintering mechanism. Among them, Fe3+ and Co2+ showed the significant beneficial effect on the grain boundary conductivity. So, electrolyte powder made of Co- and Fe-doped GDC by solid-state reaction method. And thin-film electrolyte was fabricated on the presintered Ni-GDC cermet anode substrate by E-beam evaporating method and then co-sintered to form the electrolyte/anode bilayer. We realized crystal structure of Co and Fe doped Gd0.1Ce0.9O1.95 (GDC) electrolyte by X-ray diffraction (XRD). The morphology was measured by scanning electron microscopy (SEM) for the sintered samples were performed. The performance of the cells was evaluated over 500-800 degrees C using humidified hydrogen as fuel and air as oxidant. PMID:23882837

  16. Small Scale Evaporation Kinetics of a Binary Fluid Mixture

    NASA Astrophysics Data System (ADS)

    Basdeo, Carl; Ye, Dezhuang; Kalonia, Devendra; Fan, Tai-Hsi; Mechanical Engineering Team; Pharmaceutical Sciences Collaboration

    2013-03-01

    Evaporation induces a concentrating effect in liquid mixtures. The transient process has significant influence on the dynamic behaviors of a complex fluid. To simultaneously investigate the fluid properties and small-scale evaporation kinetics during the transient process, the quartz crystal microbalance is applied to a binary mixture droplet of light alcohols including both a single volatile component (a fast evaporation followed by a slow evaporation) and a mixture of two volatile components with comparable evaporation rates. The density and viscosity stratification are evaluated by the shear wave, and the evaporation kinetics is measured by the resonant signature of the acoustic p-wave. The evaporation flux can be precisely determined by the resonant frequency spikes and the complex impedance. To predict the concentration field, the moving interface, and the precision evaporation kinetics of the mixture, a multiphase model is developed to interpret the complex impedance signals based on the underlying mass and momentum transport phenomena. The experimental method and theoretical model are developed for better characterizing and understanding of the drying process involving liquid mixtures of protein pharmaceuticals.

  17. Representative shuttle evaporative heat sink

    NASA Technical Reports Server (NTRS)

    Hixon, C. W.

    1978-01-01

    The design, fabrication, and testing of a representative shuttle evaporative heat sink (RSEHS) system which vaporizes an expendable fluid to provide cooling for the shuttle heat transport fluid loop is reported. The optimized RSEHS minimum weight design meets or exceeds the shuttle flash evaporator system requirements. A cold trap which cryo-pumps flash evaporator exhaust water from the CSD vacuum chamber test facility to prevent water contamination of the chamber pumping equipment is also described.

  18. APPLICATION OF A THIN FILM EVAPORATOR SYSTEM FOR MANAGEMENT OF LIQUID HIGH-LEVEL WASTES AT HANFORD

    SciTech Connect

    TEDESCHI AR; WILSON RA

    2010-01-14

    A modular, transportable evaporator system, using thin film evaporative technology, is planned for deployment at the Hanford radioactive waste storage tank complex. This technology, herein referred to as a wiped film evaporator (WFE), will be located at grade level above an underground storage tank to receive pumped liquids, concentrate the liquid stream from 1.1 specific gravity to approximately 1.4 and then return the concentrated solution back into the tank. Water is removed by evaporation at an internal heated drum surface exposed to high vacuum. The condensed water stream will be shipped to the site effluent treatment facility for final disposal. This operation provides significant risk mitigation to failure of the aging 242-A Evaporator facility; the only operating evaporative system at Hanford maximizing waste storage. This technology is being implemented through a development and deployment project by the tank farm operating contractor, Washington River Protection Solutions (WRPS), for the Office of River Protection/Department of Energy (ORP/DOE), through Columbia Energy & Environmental Services, Inc. (Columbia Energy). The project will finalize technology maturity and install a system at one of the double-shell tank farms. This paper discusses results of pre-project pilot-scale testing by Columbia Energy and ongoing technology maturation development scope through fiscal year 2012, including planned additional pilot-scale and full-scale simulant testing and operation with actual radioactive tank waste.

  19. Simulations of Evaporating Multicomponent Fuel Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Le Clercq, Patrick

    2005-01-01

    A paper presents additional information on the subject matter of Model of Mixing Layer With Multicomponent Evaporating Drops (NPO-30505), NASA Tech Briefs, Vol. 28, No. 3 (March 2004), page 55. To recapitulate: A mathematical model of a three-dimensional mixing layer laden with evaporating fuel drops composed of many chemical species has been derived. The model is used to perform direct numerical simulations in continuing studies directed toward understanding the behaviors of sprays of liquid petroleum fuels in furnaces, industrial combustors, and engines. The model includes governing equations formulated in an Eulerian and a Lagrangian reference frame for the gas and drops, respectively, and incorporates a concept of continuous thermodynamics, according to which the chemical composition of a fuel is described by use of a distribution function. In this investigation, the distribution function depends solely on the species molar weight. The present paper reiterates the description of the model and discusses further in-depth analysis of the previous results as well as results of additional numerical simulations assessing the effect of the mass loading. The paper reiterates the conclusions reported in the cited previous article, and states some new conclusions. Some new conclusions are: 1. The slower evaporation and the evaporation/ condensation process for multicomponent-fuel drops resulted in a reduced drop-size polydispersity compared to their single-component counterpart. 2. The inhomogeneity in the spatial distribution of the species in the layer increases with the initial mass loading. 3. As evaporation becomes faster, the assumed invariant form of the molecular- weight distribution during evaporation becomes inaccurate.

  20. Evaporative precooling unit

    SciTech Connect

    Rogers, A.R.

    1988-03-15

    In combination with a refrigeration unit, an evaporative heat exchange unit for precooling an air stream traveling toward and over the condensing coil of the refrigeration unit is described. The heat exchange unit includes: (a) a frame, (b) a porous heat transfer pad mounted in the frame; (c) nozzle means carried on the frame for directing a spray mist forwardly of the heat transfer pad, the spray mist emitted from the nozzle means initially traveling in a direction of travel such that the mist will not contact the porous heat transfer pad; (d) means mounted on the frame for causing the turbulent intermixing of the air stream with the spray mist prior to the air stream passing through the porous heat transfer pad; and (e) means for controlling the quantity of water emitted by the nozzle means such that substantially all of the spray mist is intermixed with the air stream prior to the air stream passing through the heat transfer pad.

  1. Turkish Undergraduates' Misconceptions of Evaporation, Evaporation Rate, and Vapour Pressure

    ERIC Educational Resources Information Center

    Canpolat, Nurtac

    2006-01-01

    This study focused on students' misconceptions related to evaporation, evaporation rate, and vapour pressure. Open-ended diagnostic questions were used with 107 undergraduates in the Primary Science Teacher Training Department in a state university in Turkey. In addition, 14 students from that sample were interviewed to clarify their written…

  2. Development of Intent Information Changes to Revised Minimum Aviation System Performance Standards for Automatic Dependent Surveillance Broadcast (RTCA/DO-242A)

    NASA Technical Reports Server (NTRS)

    Barhydt, Richard; Warren, Anthony W.

    2002-01-01

    RTCA Special Committee 186 has recently adopted a series of changes to the original Minimum Aviation System Performance Standards (MASPS) for Automatic Dependent Surveillance Broadcast (ADS-B). The new document will be published as DO-242A. Major changes to the MASPS include a significant restructuring and expansion of the intent parameters for future ADS-B systems. ADS-B provides a means for aircraft to exchange information about their intended trajectories with each other and with ground systems. NASA and Boeing have played significant roles in recommending these changes and providing supporting analysis. The intent changes are anticipated to provide substantial benefits to several programs and operational concepts under development by the two organizations. Major changes include the addition of Target State reports and the replacement of Trajectory Change Point reports with Trajectory Change reports. These changes have been designed to better reflect the capabilities of existing and future aircraft avionics, while providing benefits to current and proposed applications. DO-242A implements intent information elements that can be supported by current avionics systems and data buses. Provisions are made for future incorporation of other intent elements, as needed to meet operational requirements. This document summarizes the reasons for the DO-242A intent changes and provides a detailed overview of current and future intended ADS-B MASPS changes related to aircraft intent.

  3. Marangoni instability induced convection in an evaporating liquid droplet

    NASA Technical Reports Server (NTRS)

    Chai, An-Ti; Rashidnia, N.; Arpaci, V. S.

    1992-01-01

    The processes occurring when a liquid drop undergoes evaporation are described. When a liquid drop undergoes evaporation, its surface temperature decreases. If the droplet is free floating in a microgravity environment, the heat transfer process inside the droplet is initially condition controlled. As the process continues, a radial temperature gradient builds up at the free surface until the critical Marangoni number is exceeded. Then the onset of instability induces thermocapillary convective flows, which in turn speed up the evaporation. The convective flows will subside when the interior of the droplet reaches a certain equilibrium temperature, and the process will return to the diffusion controlled mode. Both preliminary modeling and recent laboratory data have confirmed that Marangoni instability induced convection can and does occur in the droplet evaporation process. Mathematical models representing Marangoni instability in an evaporating liquid drop are presented. An ideal space experiment to study and characterize the onset of Marangoni instability in an evaporating liquid droplet and to establish the effect of Marangoni instability induced convection on the droplet evaporation rate is outlined and the need for conducting such experiments in space is highlighted. However, before an opportunity to conduct experiments in space arises, ground based experiments have to be conducted to study feasibility issues and proof of concept. A ground based experiment of this type is outlined.

  4. Adiabatic burst evaporation from bicontinuous nanoporous membranes

    PubMed Central

    Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk

    2015-01-01

    Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol–gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 107 μm3 are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media. PMID:25926406

  5. Out-of-tank evaporator demonstration: Tanks focus area

    SciTech Connect

    1998-11-01

    Approximately 100 million gal of liquid waste is stored in underground storage tanks (UST)s at the Hanford Site, Idaho National Engineering and Environmental Laboratory (INEEL), Savannah River Site (SRS), and Oak Ridge Reservation (ORR). This waste is radioactive with a high salt content. The US Department of Energy (DOE) wants to minimize the volume of radioactive liquid waste in USTs by removing the excess water. This procedure conserves tank space; lowers the cost of storage; and reduces the volume of wastes subsequently requiring separation, immobilization, and disposal. The Out-of-Tank Evaporator Demonstration (OTED) was initiated to test a modular, skid-mounted evaporator. A mobile evaporator system manufactured by Delta Thermal Inc. was selected. The evaporator design was routinely used in commercial applications such as concentrating metal-plating wastes for recycle and concentrating ethylene glycol solutions. In FY 1995, the skid-mounted evaporator system was procured and installed in an existing ORNL facility (Building 7877) with temporary shielding and remote controls. The evaporator system was operational in January 1996. The system operated 24 h/day and processed 22,000 gal of Melton Valley Storage Tank (MVST) supernatant. The distillate contained essentially no salts or radionuclides. Upon completion of the demonstration, the evaporator underwent decontamination testing to illustrate the feasibility of hands-on maintenance and potential transport to another DOE facility. This report describes the process and the evaporator, its performance at ORNL, future plans, applications of this technology, cost estimates, regulatory and policy considerations, and lessons learned.

  6. Combined Evaporation and Salt Precipitation in Porous Media

    NASA Astrophysics Data System (ADS)

    Weisbrod, N.; Dragila, M. I.; Nachshon, U.; Or, D.; Shaharani, E.; Grader, A.

    2012-12-01

    The vadose zone pore water contains dissolved salts and minerals; therefore, evaporation results in high rates of salt accumulation that may change the physical and chemical properties of the porous media. Here, a series of experiments, together with a mathematical model, are presented to shed new light on these processes. Experiments included: (1) long-term column evaporation experiments to quantify changes in evaporation rates due to salt precipitation; (2) CT scans of evaporated porous media samples saturated with salt solutions, to observe salt precipitation from micro to macro scales; and (3) Infrared thermography analysis to quantify evaporation rates from porous media surfaces for homogeneous and heterogeneous conditions and constant water table, in the presence of salt precipitation. As expected, the majority of salt crystallization occurs in the upper parts of the matrix, near the evaporation front. For heterogeneous porous matrices, salt precipitation will occur mainly in the fine pore regions as preferential evaporation takes place in these locations. In addition, it was found that the precipitated NaCl salt crust diffusion coefficient for water vapor is one to two orders of magnitude lower than the vapor diffusion coefficient in free air, depending on environmental conditions and salt crystallization rates. Three new stages of evaporation were defined for saline solutions: SS1, SS2 and SS3. SS1 exhibits a low and gradual decrease in the evaporation rate due to osmotic pressure. During SS2, the evaporation rate falls progressively due to salt precipitation; SS3 is characterized by a constant low evaporation rate and determined by the diffusion rate of water vapor through the precipitated salt layer. Even though phenomenologically similar to the classical evaporation stages of pure water, these stages correspond to different mechanisms and the transition between stages can occur regardless the hydraulic conditions. As well, it was shown that matrix

  7. Vacuum flash evaporated polymer composites

    DOEpatents

    Affinito, John D.; Gross, Mark E.

    1997-01-01

    A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

  8. Vacuum flash evaporated polymer composites

    DOEpatents

    Affinito, J.D.; Gross, M.E.

    1997-10-28

    A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

  9. Treatment of evaporator condensates by pervaporation

    DOEpatents

    Blume, Ingo; Baker, Richard W.

    1990-01-01

    A pervaporation process for separating organic contaminants from evaporator condensate streams is disclosed. The process employs a permselective membrane that is selectively permeable to an organic component of the condensate. The process involves contacting the feed side of the membrane with a liquid condensate stream, and withdrawing from the permeate side a vapor enriched in the organic component. The driving force for the process is the in vapor pressure across the membrane. This difference may be provided for instance by maintaining a vacuum on the permeate side, or by condensing the permeate. The process offers a simple, economic alternative to other separation techniques.

  10. Unsaturated Hydraulic Conductivity for Evaporation in Large scale Heterogeneous Soils

    NASA Astrophysics Data System (ADS)

    Sun, D.; Zhu, J.

    2014-12-01

    In this study we aim to provide some practical guidelines of how the commonly used simple averaging schemes (arithmetic, geometric, or harmonic mean) perform in simulating large scale evaporation in a large scale heterogeneous landscape. Previous studies on hydraulic property upscaling focusing on steady state flux exchanges illustrated that an effective hydraulic property is usually more difficult to define for evaporation. This study focuses on upscaling hydraulic properties of large scale transient evaporation dynamics using the idea of the stream tube approach. Specifically, the two main objectives are: (1) if the three simple averaging schemes (i.e., arithmetic, geometric and harmonic means) of hydraulic parameters are appropriate in representing large scale evaporation processes, and (2) how the applicability of these simple averaging schemes depends on the time scale of evaporation processes in heterogeneous soils. Multiple realizations of local evaporation processes are carried out using HYDRUS-1D computational code (Simunek et al, 1998). The three averaging schemes of soil hydraulic parameters were used to simulate the cumulative flux exchange, which is then compared with the large scale average cumulative flux. The sensitivity of the relative errors to the time frame of evaporation processes is also discussed.

  11. Evaporation from the shallow Lake Massaciuccoli (Tuscany, Italy) studied using stable isotopes and evaporation pan data

    NASA Astrophysics Data System (ADS)

    Baneschi, I.; Gonfiantini, R.; Guidi, M.

    2009-04-01

    Oxygen and hydrogen isotope variations monitored in Lake Massaciuccoli (7 km2, 2 m deep, seasonally variable water level) during summer 2008, were compared with those observed in a Class A evaporation pan (diameter 120.6 cm, depth 25.4 cm) placed on the lake eastern shore. Air temperature, pressure, relative humidity, wind speed and direction, solar radiation, water temperature in the lake and the pan were also measured. The pluviometer indicated that no precipitation occurred during the study period. The pan was initially filled with groundwater up to the level of 19.2 cm (219 L), depleted in heavy isotopes with respect to tha lake water. Sodium chloride was added up to the concentration of 1 g×L-1, which is assumed do not affect significantly the evaporation rate till the water volume is reduced to less than 10 %. The Cl- concentration was used to provide an estimation of the evaporated water fraction, in addition to the micrometer measuring the water level variations. The pan water was sampled every 2-3 days and Cl- and stable isotopes determined. The set of stable isotope and evaporation data enabled us to compute the parameters governing the evaporation process and the isotopic exchanges with the atmospheric moisture, according to the procedure proposed by Gonfiantini (1986). The values were applied to test three working hypotheses of water balance of Lake Massaciuccoli: (i) surface inflow and outflow of liquid water are negligible and only evaporation is important; (ii) the inflow is negligible and outflow and evaporation are both significant; (iii) the three terms of balance are all important but the losses by evaporation and outflow exceed inflow (as the lake water level was decreasing). Water exchanges with groundwater are considered negligible. The best agreement between lake and pan data was obtained with the second hypothesis, for which the fraction of water removed by evaporation was estimated to be about 40 % ot he total water losses. This residual

  12. Experimental Investigation of Microstructured Evaporators

    NASA Astrophysics Data System (ADS)

    Wibel, W.; Westermann, S.; Maikowske, S.; Brandner, J. J.

    2012-11-01

    Microfluidic devices have become more and more popular over the last decades [1]. Cooling is a topic where microstructures offer significant advantages compared to conventional techniques due the much higher possible surface to volume ratios and short heat transfer lengths. By evaporating of a fluid in microchannels, compact, fast and powerful cooling devices become possible [2]. Experimental results for different designs of microstructured evaporators are presented here. They have been obtained either using water as evaporating coolant or the refrigerant R134a (Tetrafluoroethane). A new microstructured evaporator design consisting of bended microchannels instead of straight channels for a better performance is shown and compared to previous results [2] for the evaporation of R134a in straight microchannels.

  13. Evaporation and instabilities of microscopic capillary bridges

    PubMed Central

    Maeda, Nobuo; Israelachvili, Jacob N.; Kohonen, Mika M.

    2003-01-01

    The formation and disappearance of liquid bridges between two surfaces can occur either through equilibrium or nonequilibrium processes. In the first instance, the bridge molecules are in thermodynamic equilibrium with the surrounding vapor medium. In the second, chemical potential gradients result in material transfer; mechanical instabilities, because of van der Waals force jumps on approach or a Rayleigh instability on rapid separation, may trigger irreversible film coalescence or bridge snapping. We have studied the growth and disappearance mechanisms of laterally microscopic liquid bridges of three hydrocarbon liquids in slit-like pores. At rapid slit-opening rates, the bridges rupture by means of a mechanical instability described by the Young–Laplace equation. Noncontinuum but apparently reversible behavior is observed when a bridge is held at nanoscopic surface separations H close to the thermodynamic equilibrium Kelvin length, 2rKcosθ, where rK is the Kelvin radius and θ is the contact angle. During the course of slow evaporation (at H > 2rKcosθ) and subsequent regrowth by capillary condensation (at H < 2rKcosθ), the refractive index of the bridge may vary continuously and reversibly between that of the bulk liquid and vapor. The evaporation process becomes irreversible only at the very final stage of evaporation, when the refractive index of the fluid attains virtually that of the vapor. Measured refractive index profiles and the time-dependence of evaporating neck diameters also seem to differ from predictions based on a continuum picture of bridge evaporation far from the critical point. We discuss these findings in terms of the probable density profiles in evolving liquid bridges. PMID:12538868

  14. Condensation and Evaporation of Solar System Materials

    NASA Astrophysics Data System (ADS)

    Davis, A. M.; Richter, F. M.

    2003-12-01

    condensable matter (see Chapter 1.08; Grossman, 1973; Wänke et al., 1974; Grossman and Ganapathy, 1976; Grossman et al., 1977), where CI chondrites are taken to represent total condensable matter.Elemental abundance patterns ordered by volatility certainly could have been produced by partial condensation, but they could also have been caused by partial evaporation. The relative importance of these opposite processes is still subject to debate and uncertainty. It should be remembered that condensation calculations typically assume chemical equilibrium in a closed system, in which case the system has no memory of the path by which it arrived at a given state, and thus the chemical and isotopic composition of the condensed phase cannot be used to distinguish between partial condensation and partial evaporation. Humayun and Clayton (1995) have taken a somewhat different view by arguing that condensation and evaporation are distinguishable, in that evaporation, but not condensation, will produce isotopically fractionated residues. With this idea in mind, they carefully measured the potassium isotopic compositions of a broad range of solar system materials with different degrees of potassium depletion and found them to be indistinguishable. This they took as evidence that evaporation could not have been a significant process in determining the diverse elemental abundance patterns of the various solar system materials they measured, because had evaporation been important in fractionating potassium it would have also fractionated the potassium isotopes. We will qualify this line of reasoning by arguing that evaporation and condensation can under certain conditions produce isotopically fractionated condensed phases (i.e., that partial evaporation can produce isotopically heavy residues and that partial condensation can produce isotopically light condensates) but that under other conditions both can produce elemental fractionations without significant isotopic fractionation. The

  15. Evaporation and skin penetration characteristics of mosquito repellent formulations

    SciTech Connect

    Reifenrath, W.G.; Hawkins, G.S.; Kurtz, M.S.

    1989-03-01

    Formulations of the mosquito repellent N,N-diethyl-3-methylbenzamide (deet) in combination with a variety of additives were developed to control repellent evaporation and percutaneous penetration. Deet was also formulated with the repellent dimethyl phthalate to study the interaction of the two compounds on the skin. The evaporation and penetration processes were evaluated on whole and split-thickness pig skin using radiolabeled repellents with an in vitro apparatus. Under essentially still air and air flow conditions, one of the deet formulations resulted in significantly reduced total evaporation and percutaneous penetration of deet as compared to unformulated repellent. When deet and dimethyl phthalate were combined, neither repellent affected the total amount of evaporation and penetration of the other compound. However, initial percutaneous penetration and evaporation rates were slightly less and decayed less rapidly than when both chemicals were tested separately at the same dose. These results indicated a degree of competition of the two compounds for the same avenues of loss.

  16. Evaporation and Combustion Characteristics of Multicomponent Fuels

    NASA Astrophysics Data System (ADS)

    Govindaraju, Pavan; Stagni, Alessandro; Ihme, Matthias

    2015-11-01

    Current generation fuels are mixtures of hundreds of complicated organic compounds and accurate modeling of their combustion characteristics provides fundamental physical insights which also help in the design of efficient combustors. This however requires accurate simulation of both evaporation and combustion processes, which, in case of such fuels, demands an approach based on calculating properties using only the information of functional groups present in the mixture. The presentation will elaborate on the assumptions and the framework utilized for evaporation and chemical mechanisms. We also present a comparison between various fuels used in the aviation industry as test cases while highlighting on their pros and cons. The focus of the talk will however be on the physical aspects captured using 1D simulations, i.e., preferential evaporation of each species, ignition parameters and emissions while justifying the numerical calculations with experimental data at each stage. Further work involving the coupling of flow with evaporation and combustion can be performed and we briefly discuss why a DNS is necessary to characterize the various combustion regimes. Federal Aviation Administration.

  17. Comparison of different evaporation estimates over the African continent

    NASA Astrophysics Data System (ADS)

    Trambauer, P.; Dutra, E.; Maskey, S.; Werner, M.; Pappenberger, F.; van Beek, L. P. H.; Uhlenbrook, S.

    2014-01-01

    Evaporation is a key process in the water cycle with implications ranging, inter alia, from water management to weather forecast and climate change assessments. The estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological models or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flow. Other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products: the evaporation results from the ECMWF reanalysis ERA-Interim and ERA-Land (both based on the energy balance approach), the MOD16 evaporation product, and the GLEAM product. Three other alternative versions of the PCR-GLOBWB hydrological model were also considered. This resulted in eight products of actual evaporation, which were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and statistical methods. The comparison shows that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5° spatial resolution when averaged over the defined regions. The choice of meteorological forcing data has a larger effect on the evaporation results, especially in the case of the precipitation input as different precipitation input resulted in significantly different evaporation in some of the studied regions. ERA-Interim evaporation is generally the highest of the selected products followed by ERA-Land evaporation. In some regions, the satellite

  18. Comparison of different evaporation estimates over the African continent

    NASA Astrophysics Data System (ADS)

    Trambauer, P.; Dutra, E.; Maskey, S.; Werner, M.; Pappenberger, F.; van Beek, L. P. H.; Uhlenbrook, S.

    2013-07-01

    Evaporation is a key process in the water cycle, with implications ranging from water management, to weather forecast and climate change assessments. The estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flow. Other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products: the evaporation results from the ECMWF reanalysis ERA-Interim and ERA-Land (both based on the energy balance approach), the MOD16 evaporation product, and the GLEAM product. Three other alternative versions of the PCR-GLOBWB hydrological model were also considered. This resulted in eight products of actual evaporation, which were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and statistical methods. The comparison shows that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5° spatial resolution. The choice of meteorological forcing data has a larger effect on the evaporation results, especially in the case of the precipitation input as different precipitation input resulted in significantly different evaporation in some of the studied regions. ERA-Interim evaporation is generally the highest of the selected products followed by ERA-Land evaporation. The satellite based products (GLEAM and MOD16) do not show regular behaviour when compared

  19. Desiccant Enhanced Evaporative Air Conditioning: Parametric Analysis and Design; Preprint

    SciTech Connect

    Woods, J.; Kozubal, E.

    2012-10-01

    This paper presents a parametric analysis using a numerical model of a new concept in desiccant and evaporative air conditioning. The concept consists of two stages: a liquid desiccant dehumidifier and a dew-point evaporative cooler. Each stage consists of stacked air channel pairs separated by a plastic sheet. In the first stage, a liquid desiccant film removes moisture from the process (supply-side) air through a membrane. An evaporatively-cooled exhaust airstream on the other side of the plastic sheet cools the desiccant. The second-stage indirect evaporative cooler sensibly cools the dried process air. We analyze the tradeoff between device size and energy efficiency. This tradeoff depends strongly on process air channel thicknesses, the ratio of first-stage to second-stage area, and the second-stage exhaust air flow rate. A sensitivity analysis reiterates the importance of the process air boundary layers and suggests a need for increasing airside heat and mass transfer enhancements.

  20. Modeling Coupled Evaporation and Seepage in Ventilated Cavities

    SciTech Connect

    T. Ghezzehei; R. Trautz; S. Finsterle; P. Cook; C. Ahlers

    2004-07-01

    Cavities excavated in unsaturated geological formations are important to activities such as nuclear waste disposal and mining. Such cavities provide a unique setting for simultaneous occurrence of seepage and evaporation. Previously, inverse numerical modeling of field liquid-release tests and associated seepage into cavities were used to provide seepage-related large-scale formation properties by ignoring the impact of evaporation. The applicability of such models was limited to the narrow range of ventilation conditions under which the models were calibrated. The objective of this study was to alleviate this limitation by incorporating evaporation into the seepage models. We modeled evaporation as an isothermal vapor diffusion process. The semi-physical model accounts for the relative humidity, temperature, and ventilation conditions of the cavities. The evaporation boundary layer thickness (BLT) over which diffusion occurs was estimated by calibration against free-water evaporation data collected inside the experimental cavities. The estimated values of BLT were 5 to 7 mm for the open underground drifts and 20 mm for niches closed off by bulkheads. Compared to previous models that neglected the effect of evaporation, this new approach showed significant improvement in capturing seepage fluctuations into open cavities of low relative humidity. At high relative-humidity values (greater than 85%), the effect of evaporation on seepage was very small.

  1. Impacts of Salinity on Soil Hydraulic Properties and Evaporation Fluxes

    NASA Astrophysics Data System (ADS)

    Fierro, V.; Cristi Matte, F.; Suarez, F. I.; Munoz, J. F.

    2014-12-01

    Saline soils are common in arid zones, where evaporation from shallow groundwater is generally the main component of the water balance. Thus, to correctly manage water resources in these zones, it is important to quantify the evaporation fluxes. Evaporation from saline soils is a complex process that couples the movement of salts, heat, liquid water and water vapor, and strongly depends on the soil water content. Precipitation/dissolution reactions can change the soil structure and alter flow paths, modifying evaporation fluxes. We utilized the HYDRUS-1D model to investigate the effects of salinity on soil hydraulic properties and evaporation fluxes. HYDRUS-1D simulates the transport of liquid water, water vapor, and heat, and can incorporate precipitation/dissolution reactions of the major ions. To run the model, we determined the water retention curve for a soil with different salinities; and we used meteorological forcing from an experimental site from the Atacama Desert. It was found that higher sodium adsorption ratios in the soil increase the soil water retention capacity. Also, it was found that evaporation fluxes increase salts concentration near the soil surface, changing the soil's water retention capacity in that zone. Finally, movement of salts causes differences in evaporation fluxes. It is thus necessary to incorporate salt precipitation/dissolution reactions and its effects on the water retention curve to correctly simulate evaporation in saline soils

  2. A realistic model of evaporation for a liquid droplet

    NASA Technical Reports Server (NTRS)

    Chai, An-Ti; Arpaci, V. S.

    1994-01-01

    An intuitive delineation along with dimensional considerations and experimental evidences are presented to show that in a general case, the evaporation of a liquid droplet undergoes three regimes through the process. Initially, the heat transfer inside the evaporating droplets is conduction controlled; then, in the second stage, convective heat transfer may take over; finally, the convections subside, and the process returns to conduction controlled mode.

  3. Modeling of Bulk Evaporation and Condensation

    NASA Technical Reports Server (NTRS)

    Anghaie, S.; Ding, Z.

    1996-01-01

    This report describes the modeling and mathematical formulation of the bulk evaporation and condensation involved in liquid-vapor phase change processes. An internal energy formulation, for these phase change processes that occur under the constraint of constant volume, was studied. Compared to the enthalpy formulation, the internal energy formulation has a more concise and compact form. The velocity and time scales of the interface movement were obtained through scaling analysis and verified by performing detailed numerical experiments. The convection effect induced by the density change was analyzed and found to be negligible compared to the conduction effect. Two iterative methods for updating the value of the vapor phase fraction, the energy based (E-based) and temperature based (T-based) methods, were investigated. Numerical experiments revealed that for the evaporation and condensation problems the E-based method is superior to the T-based method in terms of computational efficiency. The internal energy formulation and the E-based method were used to compute the bulk evaporation and condensation processes under different conditions. The evolution of the phase change processes was investigated. This work provided a basis for the modeling of thermal performance of multi-phase nuclear fuel elements under variable gravity conditions, in which the buoyancy convection due to gravity effects and internal heating are involved.

  4. Process-Parameter-Dependent Optical and Structural Properties of ZrO2MgO Mixed-Composite Films Evaporated from the solid Solution

    NASA Technical Reports Server (NTRS)

    Sahoo, N. K.; Shapiro, A. P.

    1998-01-01

    The process-parameter-dependent optical and structural properties of ZrO2MgO mixed-composite material have been investigated. Optical properties were derived from spectrophotometric measurements. By use of atomic force microscopy, x-ray diffraction analysis, and energy-dispersive x-ray (EDX) analysis, the surface morphology, grain size distributions, crystallographic phases, and process-dependent material composition of films have been investigated. EDX analysis made evident the correlation between the oxygen enrichment in the films prepared at a high level of oxygen pressure and the very low refractive index. Since oxygen pressure can be dynamically varied during a deposition process, coatings constructed of suitable mixed-composite thin films can benefit from continuous modulation of the index of refraction. A step modulation approach is used to develop various multilayer-equivalent thin-film devices.

  5. Evaporative cooling of flare plasma

    NASA Technical Reports Server (NTRS)

    Antiochos, S. K.; Sturrock, P. A.

    1976-01-01

    A one-dimensional loop model for the evaporative cooling of the coronal flare plasma was investigated. Conductive losses dominated radiative cooling, and the evaporative velocities were small compared to the sound speed. The profile and evolution of the temperature were calculated. The model was in agreement with soft X-ray observations on the evolution of flare temperatures and emission measures. The effect of evaporation was to greatly reduce the conductive heat flux into the chromosphere and to enhance the EUV emission from the coronal flare plasma.

  6. Evaporative cooling of flare plasma

    NASA Technical Reports Server (NTRS)

    Antiochos, S. K.; Sturrock, P. A.

    1978-01-01

    We investigate a one-dimensional loop model for the evaporative cooling of the coronal flare plasma. The important assumptions are that conductive losses dominate radiative cooling and that the evaporative velocities are small compared with the sound speed. We calculate the profile and evolution of the temperature and verify the accuracy of our assumptions for plasma parameters typical of flare regions. The model is in agreement with soft X-ray observations on the evolution of flare temperatures and emission measures. The effect of evaporation is to greatly reduce the conductive heat flux into the chromosphere and to enhance the EUV emission from the coronal flare plasma.

  7. Evaporation of sessile droplets on nano-porous alumina surfaces

    NASA Astrophysics Data System (ADS)

    Singh, Sanchit K.; Pratap, Dheeraj; Ramakrishna, S. Anantha; Khanderkar, Sameer

    2013-07-01

    An experimental investigation of evaporation of sessile droplets is presented on nano-porous alumina surfaces with different pore distribution morphologies and pore sizes. Evaporation can be considered as a quasi-steady-state process, such that the vapor concentration distribution above the droplet satisfies the Laplace equation, but with a timevarying droplet surface. For benchmarking, the evaporation of sessile water and ethanol droplets is also investigated on standard borosilicate glass and Teflon surfaces respectively, and results are compared with the previous work. Contact angle variation with time is also recorded and high speed videos showing the spreading process of droplets on nanoporous surfaces are taken. The results clearly show that nano-structuring is an effective tool to control wettability as well as the diffusive evaporation process.

  8. Evaporation Dynamics of Moss and Bare Soil in Boreal Forests

    NASA Astrophysics Data System (ADS)

    Dempster, S.; Young, J. M.; Barron, C. G.; Bolton, W. R.

    2013-12-01

    Evaporation dynamics of mosses is a critical process in boreal and arctic systems and represents a key uncertainty in hydrology and climate models. At this point, moss evaporation is not well quantified at the plot or landscape scale. Relative to bare soil or litter evaporation, moss evaporation can be challenging to predict because the water flux is not isolated to the moss surface. Evaporation can originate from nearly 10 cm below the surface. Some mosses can wick moisture from even deeper than 10 cm, which subsequently evaporates. The goal of this study was to use field measurements to quantify the moss evaporation dynamics in a coniferous forest relative to bare ground or litter evaporation dynamics in a deciduous forest in Interior Alaska. Measurements were made in two ecosystem types within the boreal forest of Interior Alaska: a deciduous forest devoid of moss and a coniferous forest with a thick moss layer. A small clear chamber was attached to a LiCor 840 infrared gas analyzer in a closed loop system with a low flow rate. Water fluxes were measured for ~ 90 seconds on each plot in dry and wet soil and moss conditions. Additional measurements included: soil temperature, soil moisture, air temperature, barometric pressure, dew point, relative humidity, and wind speed. Thermal infrared images were also captured in congruence with water flux measurements to determine skin temperature. We found that the moss evaporation rate was over 100% greater than the soil evaporation rate (0.057 g/min vs. 0.024 g/min), and evaporation rates in both systems were most strongly driven by relative humidity and surface temperature. Surface temperature was lower at the birch site than the black spruce site because trees shade the surface beneath the birch. High fluxes associated with high water content were sustained for a longer period of time over the mosses compared to the bare soil. The thermal IR data showed that skin temperature lagged the evaporation flux, such that the

  9. Novel technology for hydrothermal treatment of NPP evaporator concentrates

    SciTech Connect

    Avramenko, Valentin; Dobrzhansky, Vitaly; Marinin, Dmitry; Sergienko, Valentin; Shmatko, Sergey

    2007-07-01

    A novel technology was developed for treatment of evaporator concentrates produced as a result of operation of evaporation devices comprising the main component of special water purification systems of nuclear power plants (NPP). The developed technology includes a hydrothermal (T=250-300 deg. C and P=80-120 bar) processing of evaporator concentrates in oxidation medium in order to destruct stable organic complexes of cobalt radionuclides and remove these radionuclides by oxide materials formed during such a processing. The cesium radionuclides contained in evaporator concentrates are removed by a conventional method-through application of one of the developed composite sorbents with ferrocyanides of transition metals used as active agents. Extensive laboratory studies of the processes occurring in evaporator concentrates under hydrothermal conditions were performed. It was shown that hydrothermal oxidation of evaporator concentrates has a number of advantages as compared to traditional oxidation methods (ozonization, photo-catalytic, electrochemical and plasma oxidation). A laboratory installation was built for the flow-type hydrothermal oxidation of NPP evaporator concentrates. The obtained experimental results showed good prospects for the developed method application. On the basis of the results obtained, a pilot installation of productivity up to 15 l/hour was developed and built in order to work out the technology of evaporator concentrates hydrothermal treatment. The pilot tests of the hydrothermal technology for evaporator concentrates hydrothermal treatment were performed for 6 months in 2006 at the 1. reactor unit of the Novovoronezhskaya NPP (Voronezh Region, Russia). Optimal technological regimes were determined, and estimations of the economic soundness of the technology were made. The advantages of the presented technology in terms of management of concentrated liquid radioactive wastes (LRW) at nuclear cycle facilities, as compared to other methods

  10. The Savannah River Site Replacement High Level Radioactive Waste Evaporator Project

    SciTech Connect

    Presgrove, S.B.

    1992-08-01

    The Replacement High Level Waste Evaporator Project was conceived in 1985 to reduce the volume of the high level radioactive waste Process of the high level waste has been accomplished up to this time using Bent Tube type evaporators and therefore, that type evaporator was selected for this project. The Title I Design of the project was 70% completed in late 1990. The Department of Energy at that time hired an independent consulting firm to perform a complete review of the project. The DOE placed a STOP ORDER on purchasing the evaporator in January 1991. Essentially, no construction was to be done on this project until all findings and concerns dealing with the type and design of the evaporator are resolved. This report addresses two aspects of the DOE design review; (1) Comparing the Bent Tube Evaporator with the Forced Circulation Evaporator, (2) The design portion of the DOE Project Review - concentrated on the mechanical design properties of the evaporator. 1 ref.

  11. The Savannah River Site Replacement High Level Radioactive Waste Evaporator Project

    SciTech Connect

    Presgrove, S.B. )

    1992-01-01

    The Replacement High Level Waste Evaporator Project was conceived in 1985 to reduce the volume of the high level radioactive waste Process of the high level waste has been accomplished up to this time using Bent Tube type evaporators and therefore, that type evaporator was selected for this project. The Title I Design of the project was 70% completed in late 1990. The Department of Energy at that time hired an independent consulting firm to perform a complete review of the project. The DOE placed a STOP ORDER on purchasing the evaporator in January 1991. Essentially, no construction was to be done on this project until all findings and concerns dealing with the type and design of the evaporator are resolved. This report addresses two aspects of the DOE design review; (1) Comparing the Bent Tube Evaporator with the Forced Circulation Evaporator, (2) The design portion of the DOE Project Review - concentrated on the mechanical design properties of the evaporator. 1 ref.

  12. Ensemble Evaporation Predictions from Remote Sensing in the Nile Basin

    NASA Astrophysics Data System (ADS)

    Bastiaanssen, W. G.; Hofste, R.; Senay, G. B.; Anderson, M. C.; van Dijk, A.; Pelgrum, H.; Seid, A. H.; Miralles, D.; Hurk, B. V. D.; Wada, Y.; Rebelo, L. M.; Smakhtin, V.

    2014-12-01

    Water scarcity is increasing globally and is most evident in arid zones. Most rainfall is evaporated and runoff coefficients of 5 to 10% are common in arid zone river basins. Evaporation is the most important hydrological process, not only because of its magnitude, but also because it can be managed and regulated by withdrawals, irrigation equipment, agricultural practices, land use changes and soil treatments. Hence, evaporation can be modified and the looming water crisis prompt us to think more careful on how water is consumed and the services and benefits we render on return in terms of agricultural production, ecosystem services, hydropower, leisure etc. Several lead research groups have developed global evaporation products, at least for the African continent. Most of these products have a pixel size varying between 1 to 3 km, and this is a reasonable tradeoff between what is technically preferred (evaporation by land use class) and what can be operationally inferred from the newest earth observation satellites (100 to 1000 m pixels with revisit time of 1 to 5 days). The evaporation variability from monthly SSEBop, ALEXI, CMRSET, NBI version of MOD16, GLEAM and LandSAF model outputs for the main land use classes of the Nile will be demonstrated for the period 2005 to 2012. For 2007, there is also an evaporation data set from ETLook available. The largest variabilities occur on irrigated land, open water bodies and flood plains. The evaporation predictions are compared against flux tower data, and the water balance of paired catchments in Ethiopia and Southern Sudan. It is proposed to use ensemble averages and spreads of actual evaporation values for applications in water management, rather than using one single value and one single model. Some first thoughts on ensemble averaging will be provided. Ensemble evaporation values will be applied in the Water Accounting Plus (WA+) system, being a new analytical framework for water resources assessment reporting

  13. Evaporative cooling: effective latent heat of evaporation in relation to evaporation distance from the skin.

    PubMed

    Havenith, George; Bröde, Peter; den Hartog, Emiel; Kuklane, Kalev; Holmer, Ingvar; Rossi, Rene M; Richards, Mark; Farnworth, Brian; Wang, Xiaoxin

    2013-03-15

    Calculation of evaporative heat loss is essential to heat balance calculations. Despite recognition that the value for latent heat of evaporation, used in these calculations, may not always reflect the real cooling benefit to the body, only limited quantitative data on this is available, which has found little use in recent literature. In this experiment a thermal manikin, (MTNW, Seattle, WA) was used to determine the effective cooling power of moisture evaporation. The manikin measures both heat loss and mass loss independently, allowing a direct calculation of an effective latent heat of evaporation (λeff). The location of the evaporation was varied: from the skin or from the underwear or from the outerwear. Outerwear of different permeabilities was used, and different numbers of layers were used. Tests took place in 20°C, 0.5 m/s at different humidities and were performed both dry and with a wet layer, allowing the breakdown of heat loss in dry and evaporative components. For evaporation from the skin, λeff is close to the theoretical value (2,430 J/g) but starts to drop when more clothing is worn, e.g., by 11% for underwear and permeable coverall. When evaporation is from the underwear, λeff reduction is 28% wearing a permeable outer. When evaporation is from the outermost layer only, the reduction exceeds 62% (no base layer), increasing toward 80% with more layers between skin and wet outerwear. In semi- and impermeable outerwear, the added effect of condensation in the clothing opposes this effect. A general formula for the calculation of λeff was developed. PMID:23329814

  14. Evaporation effects in elastocapillary aggregation

    NASA Astrophysics Data System (ADS)

    Vella, Dominic; Hadjittofis, Andreas; Singh, Kiran; Lister, John

    2015-11-01

    We consider the effect of evaporation on the aggregation of a number of elastic objects due to a liquid's surface tension. In particular, we consider an array of spring-block elements in which the gaps between blocks are filled by thin liquid films that evaporate during the course of an experiment. Using lubrication theory to account for the fluid flow within the gaps, we study the dynamics of aggregation. We find that a non-zero evaporation rate causes the elements to aggregate more quickly and, indeed, to contact within finite time. However, we also show that the number of elements within each cluster decreases as the evaporation rate increases. We explain these results quantitatively by comparison with the corresponding two-body problem and discuss their relevance for controlling pattern formation in carbon nanotube forests.

  15. Explosive evaporation in solar flares

    NASA Technical Reports Server (NTRS)

    Fisher, George H.

    1987-01-01

    This paper develops a simple analytical model for the phenomenon of 'explosive evaporation' driven by nonthermal electron heating in solar flares. The model relates the electron energy flux and spectrum, plus details of the preflare atmosphere, to the time scale for explosive evaporation to occur, the maximum pressure and temperature to be reached, rough estimates for the UV pulse emission flux and duration, and the evolution of the blueshifted component of the soft X-ray lines. An expression is given for the time scale for buildup to maximum pressures and the onset of rapid motion of the explosively evaporating plasma. This evaporation can excite a rapid response of UV line and continuum emission. The emission lines formed in the plasma approach a given emissivity-weighted blueshift speed.

  16. Dual manifold heat pipe evaporator

    DOEpatents

    Adkins, Douglas R.; Rawlinson, K. Scott

    1994-01-01

    An improved evaporator section for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes.

  17. Dual manifold heat pipe evaporator

    DOEpatents

    Adkins, D.R.; Rawlinson, K.S.

    1994-01-04

    An improved evaporator section is described for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes. 1 figure.

  18. Horst Meyer and Quantum Evaporation

    NASA Astrophysics Data System (ADS)

    Balibar, S.

    2016-06-01

    With their 1963 article in Cryogenics Horst Meyer and his collaborators triggered intense research activity on the evaporation of superfluid helium. Discussing this subject with him in 1975 was enlightening. Fifty years later, the analogy between the photoelectric effect and the evaporation of superfluid helium in the low temperature limit is not yet clear, although remarkable progress has been made in its observation and its understanding. This special issue of the Journal of Low Temperature Physics is an opportunity to recall the history of quantum evaporation, and to express my gratitude to Horst Meyer. It describes quickly most of the experimental and theoretical works which have been published on quantum evaporation during the last 50 years, but it is not a comprehensive review of this fascinating subject.

  19. Evaporation Tower With Prill Nozzles

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1984-01-01

    Tower more efficient than conventional evaporation equipment. Liquids such as milk and fruit juice concentrated by passing them through tiny nozzle to form droplets, then allowing droplets to fall through evacuated tower with cooled walls.

  20. Externally Induced Evaporation of Young Stellar Disks in Orion

    NASA Technical Reports Server (NTRS)

    Johnstone, D.; Hollenbach, D.; Shu, F.

    1996-01-01

    In this paper we propose a model for the evaporation of disks around young low-mass stars by external sources of high energy photons. Two evaporation techniques are possible. Lyman continuum radiation can ionize hydrogen at the disk surface powering a steady thermal ionized disk-wind, or FUV radiation can heat the disk through photo-electric grain processes powering a slower thermal neutral disk-wind. Applying these two models to the evaporating objects in the Trapezium produces a satisfactory solution to both the mass-loss rate and size of the ionized envelopes.

  1. (Anti-)evaporation of Schwarzschild-de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Bousso, Raphael; Hawking, Stephen W.

    1998-02-01

    We study the quantum evolution of black holes immersed in a de Sitter background space. For black holes whose size is comparable to that of the cosmological horizon, this process differs significantly from the evaporation of asymptotically flat black holes. Our model includes the one-loop effective action in the s-wave and large N approximation. Black holes of the maximal mass are in equilibrium. Unexpectedly, we find that nearly maximal quantum Schwarzschild-de Sitter black holes anti-evaporate. However, there is a different perturbative mode that leads to evaporation. We show that this mode will always be excited when a pair of cosmological holes nucleates.

  2. Surprises in the evaporation of 2D black holes.

    PubMed

    Ashtekar, Abhay; Pretorius, Frans; Ramazanoğlu, Fethi M

    2011-04-22

    Quantum evaporation of Callan-Giddings-Harvey-Strominger black holes is analyzed in the mean-field approximation, incorporating backreaction. Detailed analytical and numerical calculations show that, while some of the assumptions underlying the standard evaporation paradigm are borne out, several are not. Furthermore, if the black hole is initially macroscopic, the evaporation process exhibits remarkable universal properties (which are distinct from the features observed in the simplified, exactly soluble models). Finally, our results provide support for the full quantum gravity scenario recently developed by Ashtekar, Taveras, and Varadarajan. PMID:21599354

  3. a Self-Consistent Model of the Black Hole Evaporation

    NASA Astrophysics Data System (ADS)

    Kawai, Hikaru; Matsuo, Yoshinori; Yokokura, Yuki

    2013-06-01

    We construct a self-consistent model which describes a black hole from formation to evaporation including the backreaction from the Hawking radiation. In the case where a null shell collapses, at the beginning the evaporation occurs, but it stops eventually, and a horizon and singularity appear. On the other hand, in the generic collapse process of a continuously distributed null matter, the black hole evaporates completely without forming a macroscopically large horizon nor singularity. We also find a stationary solution in the heat bath, which can be regarded as a normal thermodynamic object.

  4. Defect formation in Cu(In,Ga)Se{sub 2} thin films due to the presence of potassium during growth by low temperature co-evaporation process

    SciTech Connect

    Pianezzi, F. Reinhard, P.; Chirilă, A.; Nishiwaki, S.; Bissig, B.; Buecheler, S.; Tiwari, A. N.

    2013-11-21

    Doping the Cu(In,Ga)Se{sub 2} (CIGS) absorber layer with alkaline metals is necessary to process high efficiency solar cells. When growth of CIGS solar cells is performed on soda-lime glass (SLG), the alkaline elements naturally diffuse from the substrate into the absorber layer. On the other hand, when CIGS is grown on alkaline free substrates, the alkaline metals have to be added from another source. In the past, Na was believed to be the most important dopant of the alkaline elements, even though K was also observed to diffuse into CIGS from the SLG. Recently, the beneficial effect of a post deposition treatment with KF was pointed out and enabled the production of a 20.4% CIGS solar cell grown at low substrate temperature (<500 °C). However, possible negative effects of the presence or addition of the alkaline impurities during the low temperature growth process were observed for Na, but were not investigated for K so far. In this study, we investigate in detail the role of K on the defect formation in CIGS layers deposited at low temperature on alkaline free polyimide with intentional addition of K during selected time intervals of the CIGS layer growth. By means of admittance spectroscopy and deep level transient spectroscopy, we identify a deep minority carrier trap at around 280 meV below the conduction band E{sub C} in CIGS layers grown with K. Its influence on recombination and minority carrier lifetime in the absorber layer is investigated with external quantum efficiency measurements and time-resolved photoluminescence. Furthermore, to support the experimental findings device simulations were performed using the software SCAPS.

  5. Production of stable tellurium evaporated targets

    NASA Astrophysics Data System (ADS)

    Greene, John P.; Palumbo, Annalia; Tan, Wanpeng; Görres, Joachim; Wiescher, Michael C.

    2008-06-01

    Due to the low melting point of tellurium metal, self-supporting Te targets degrade quickly when exposed to particle beams. This situation is greatly improved if the tellurium material is evaporated onto C foil backings. Elastic scattering in target and backing layers broadens the Te peak, making measurements difficult, while too little material reduces the reaction rate. Therefore, it is necessary to optimize the target thickness. Evaporated metallic and oxide Te targets were prepared at Argonne National Laboratory by vacuum deposition from a resistively heated source boat. The stability of the targets was then tested by exposing them to a varying intensity alpha beam with an energy range from 17 to 27 MeV using the FN Tandem Van de Graaff accelerator at the University of Notre Dame. Optimal target thicknesses and beam currents were then obtained for p-process experiments. A description of the apparatus and production method will be presented.

  6. Black hole evaporation rates without spacetime.

    PubMed

    Braunstein, Samuel L; Patra, Manas K

    2011-08-12

    Verlinde recently suggested that gravity, inertia, and even spacetime may be emergent properties of an underlying thermodynamic theory. This vision was motivated in part by Jacobson's 1995 surprise result that the Einstein equations of gravity follow from the thermodynamic properties of event horizons. Taking a first tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole event horizons in a spacetime-free manner. Our result relies on a Hilbert space description of black hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes, global conservation of the no-hair quantities, and the existence of Penrose processes. Our analysis is not wedded to standard general relativity and so should apply to extended gravity theories where we find that the black hole area must be replaced by some other property in any generalized area theorem. PMID:21902381

  7. The interaction of evaporative and convective instabilities

    NASA Astrophysics Data System (ADS)

    Ozen, O.

    Evaporative convection arises in a variety of natural and industrial processes, such as drying of lakebeds, heat pipe technology and dry-eye syndrome. The phenomenon of evaporative convection leads to an interfacial instability where an erstwhile flat surface becomes undulated as a control variable, such as temperature drop, exceeds a critical value. This instability has been investigated by others assuming that the vapor phase is infinitely deep and passive, i.e. vapor fluid dynamics has been ignored. However, when we look at some engineering processes, such as distillation columns, heat pipes and drying technologies where phase change takes place we might imagine that the assumption of an infinitely deep vapor layer or at least that of a passive vapor is inappropriate. Previous work on convection in bilayer systems with no phase-change suggests that active vapor layers play a major role in determining the stability of an interface. Hence, for the case of convection with phase-change, we will address this issue and try to answer the question whether the infinitely deep and passive vapor layer is a valid assumption. We have also investigated, theoretically, the gravity and surface tension gradient-driven instabilities occurring during the evaporation of a liquid into its own vapor taking into account the fluid dynamics of both phases and the finiteness of the domains of each phase, i.e. the liquid and its vapor are assumed to be confined between two horizontal plates, and different heating arrangements are applied. The effects of fluid layer depths, the evaporation rate and the temperature gradient applied across the fluids on the stability of the interface are studied. The modes of the flow pattern are determined for each scenario. The physics of the instability are explained and a comparison is made with the results of similar, yet physically different problems.

  8. Relationships between evaporation and moisture content in historical masonry

    NASA Astrophysics Data System (ADS)

    López-González, Laura; Ortiz de Cosca, Raquel Otero; García-Morales, Soledad; Gomez-Heras, Miguel

    2016-04-01

    The "materiaĺs evaporative behaviour" describe how on site materials evaporate in real conditions, not only due to indoor conditions (air temperature and humidity ratio, etc), but also because it is influenced by multiple factors (building systems, materials, environmental conditions, etc), some of which can difficult the evaporation process, such as as hygroscopic salts presence. This evaporative behaviour may or may not have a direct relation to the actual moisture within the walls. This paper presents thermohygrometric data and a electrical resistivity survey from a half-buried wall of the Hermit of Humilladero (Ávila, Spain 16th century), a building that displays intense moisture-related decay in that wall. Thermohygrometric data allowed characterising the evaporative behaviour while the resistivity survey allowed inferring the moisture in the masonry. Salt's presence was also mapped. These sets of data were statistically analysed to observe the significance of the correlation, if any and characterise the evaporative behaviour by discerning the different information obtained from each technique. The different measurements obtained by these techniques were combined using GIS software. This allowed obtaining maps that combine evaporation and moisture data represented by "factors" (i.e. a global value obtained as a sum of different properties). The combination of these tests allowed a better characterization and understanding of wetting and drying cycles aiming to develop a correct diagnosis system. Research funded by Madrid's Regional Government project Geomateriales 2 S2013/MIT-2914

  9. Atmospheric convective transport contribution to evaporative sessile droplets

    NASA Astrophysics Data System (ADS)

    Carle, Florian; Semenov, Sergey; Medale, Marc; Brutin, David

    2014-11-01

    The scientific community struggles with the creation of an accurate quantitative description of sessile droplet evaporation flux rate. The classically used description considers evaporation as a quasi-steady process controlled by the diffusion of vapor into the air, and the whole system is assumed to be isothermal at the ambient temperature. However, when two types of fluids (alcohols and alkanes) are let to evaporate on heated substrates while a side view camera measures their evaporation flux rate, droplets tend to see their evaporation flux rate underestimated by this model mostly due to convection. This experimental study aims to understand how atmospheric convective transport in the vapor phase influences evaporation in order to developed an empirical model that describes with accuracy the evaporation flux rate. The Rayleigh number is used to analyze the contribution of natural convection and an empirical model is developed combining diffusive and convective transport for each type of fluid. The influence of the molecular chain length (and the increasing number of carbon atoms) is also being discussed.

  10. Theoretical and testing performance of an innovative indirect evaporative chiller

    SciTech Connect

    Jiang, Yi; Xie, Xiaoyun

    2010-12-15

    An indirect evaporative chiller is a device used to produce chilled water at a temperature between the wet bulb temperature and dew point of the outdoor air, which can be used in building HVAC systems. This article presents a theoretical analysis and practical performance of an innovative indirect evaporative chiller. First, the process of the indirect evaporative chiller is introduced; then, the matching characteristics of the process are presented and analyzed. It can be shown that the process that produces cold water by using dry air is a nearly-reversible process, so the ideal produced chilled water temperature of the indirect evaporative chiller can be set close to the dew point temperature of the chiller's inlet air. After the indirect evaporative chiller was designed, simulations were done to analyze the output water temperature, the cooling efficiency relative to the inlet dew point temperature, and the COP that the chiller can performance. The first installation of the indirect evaporative chiller of this kind has been run for 5 years in a building in the city of Shihezi. The tested output water temperature of the chiller is around 14-20 C, which is just in between of the outdoor wet bulb temperature and dew point. The tested COP{sub r,s} of the developed indirect evaporative chiller reaches 9.1. Compared with ordinary air conditioning systems, the indirect evaporative chiller can save more than 40% in energy consumption due to the fact that the only energy consumed is from pumps and fans. An added bonus is that the indirect evaporative chiller uses no CFCs that pollute to the aerosphere. The tested internal parameters, such as the water-air flow rate ratio and heat transfer area for each heat transfer process inside the chiller, were analyzed and compared with designed values. The tested indoor air conditions, with a room temperature of 23-27 C and relative humidity of 50-70%, proved that the developed practical indirect evaporative chiller successfully

  11. Convective heat and mass transfer during the evaporation of a liquid into a gas flow

    NASA Astrophysics Data System (ADS)

    Boiarshinov, B. F.; Volchkov, E. P.; Terekhov, V. I.

    1985-10-01

    Heat and mass transfer processes associated with liquid evaporation are analyzed for adiabatic and nonadiabatic conditions. Experimental data are then presented on heat and mass transfer during the evaporation of water and ethyl alcohol from a porous surface. It is shown that heat and mass transfer under conditions of evaporation can be described by using expressions for flow past a 'dry' wall. A diagram is presented for determining the magnitudes of additional heat sources in the case of nonadiabatic evaporation. Finally, the effect of various factors, such as temperature, flow humidity, and liquid type, on heat and mass transfer during evaporation is analyzed for laminar and turbulent flows.

  12. Reservoir evaporation in central Colorado

    USGS Publications Warehouse

    Spahr, N.E.; Ruddy, B.C.

    1983-01-01

    Evaporation losses from seven reservoirs operated by the Denver Water Department in central Colorado were determined during various periods from 1974 to 1980. The reservoirs studies were Ralston, Cheesman, Antero, Williams Fork, Elevenmile Canyon, Dillon, and Gross. Energy-budget and mass-transfer methods were used to determine evaporation. Class-A pan data also were collected at each reservoir. The energy-budget method was the most accurate of the methods used to determine evaporation. At Ralston, Cheesman, Antero, and Williams Fork Reservoirs the energy-budget method was used to calibrate the mass-transfer coefficients. Calibrated coefficients already were available for Elevenmile Canyon, Dillon, and Gross Reservoirs. Using the calibrated coefficients, long-term mass-transfer evaporation rates were determined. Annual evaporation values were not determined because the instrumentation was not operated for the entire open-water season. Class-A pan data were used to determine pan coefficients for each season at each reservoir. The coefficients varied from season to season and between reservoirs, and the seasonal values ranged from 0.29 to 1.05. (USGS)

  13. Corrosion study of simulated evaporator components

    SciTech Connect

    Schreiber, S.B.; Dunn, S.L.

    1989-07-01

    At the Los Alamos Plutonium Facility, ion exchange effluents and precipitation filtrates containing discardable levels of transuranic elements are concentrated using a thermosiphon evaporator before cement fixation for waste disposal. Because of changing process feed streams and scrap recovery requirements, trace amounts of free chloride ions (Cl/sup /minus//) are being introduced into the stainless steel (SS) evaporator, potentially increasing corrosion rates and thereby reducing its useful life. This study was performed to determine the effects of Cl/sup /minus// in simulated evaporator feed solutions that contain significant amounts of ferric ions (Fe/sup 3+/) in nitric acid (HNO/sub 3/). A simulated environment was produced by heating 316 SS cans that contained various tests solutions. The surface was monitored for signs of pitting or stress cracking, and vessel weight loss was measured on a daily basis to establish a rough corrosion rate. The final conclusion is that the nitric acid solution provides enough free nitrate ions (NO/sub 3//sup /minus//) to maintain minimal corrosion in a dilute ferric chloride environment. 3 refs., 5 figs., 10 tabs.

  14. Transient Marangoni convection in hanging evaporating drops

    NASA Astrophysics Data System (ADS)

    Savino, R.; Fico, S.

    2004-10-01

    A combined experimental and numerical analysis has been carried out to study Marangoni effects during the evaporation of droplets. The experiments are performed with pendant drops of silicone oils (with different viscosities) and hydrocarbons. The temperature of the disk sustaining the drop is rapidly increased or decreased in order to study transient heating or cooling processes. The velocity field in the droplet is evaluated monitoring the motion of tracers in the meridian plane, using a laser sheet illumination system and a video camera. Surface temperature distributions of the drops are detected by infrared thermocamera. The numerical model is based on axisymmetric Navier-Stokes equations, taking into account the presence of Marangoni shear stresses and evaporative cooling at the liquid-air interface. Marangoni flows cause a larger, more uniform surface temperature, increasing heat transfer from disk to droplet, as well as evaporation rate. When Marangoni effects are negligible, larger surface temperature differences occur along the drop surface and heat transfer is relatively small. The role of Marangoni and buoyancy flows in silicone oils with different viscosities and hydrocarbons is discussed and correlations are presented between experimental and numerical results.

  15. Fluid Flow in An Evaporating Droplet

    NASA Technical Reports Server (NTRS)

    Hu, H.; Larson, R.

    1999-01-01

    Droplet evaporation is a common phenomenon in everyday life. For example, when a droplet of coffee or salt solution is dropped onto a surface and the droplet dries out, a ring of coffee or salt particles is left on the surface. This phenomenon exists not only in everyday life, but also in many practical industrial processes and scientific research and could also be used to assist in DNA sequence analysis, if the flow field in the droplet produced by the evaporation could be understood and predicted in detail. In order to measure the fluid flow in a droplet, small particles can be suspended into the fluid as tracers. From the ratio of gravitational force to Brownian force a(exp 4)(delta rho)(g)/k(sub B)T, we find that particle's tendency to settle is proportional to a(exp 4) (a is particle radius). So, to keep the particles from settling, the droplet size should be chosen to be in a range 0.1 -1.0 microns in experiments. For such small particles, the Brownian force will affect the motion of the particle preventing accurate measurement of the flow field. This problem could be overcome by using larger particles as tracers to measure fluid flow under microgravity since the gravitational acceleration g is then very small. For larger particles, Brownian force would hardly affect the motion of the particles. Therefore, accurate flow field could be determined from experiments in microgravity. In this paper, we will investigate the fluid flow in an evaporating droplet under normal gravity, and compare experiments to theories. Then, we will present our ideas about the experimental measurement of fluid flow in an evaporating droplet under microgravity.

  16. A New Microstructure Device for Efficient Evaporation of Liquids

    NASA Astrophysics Data System (ADS)

    Brandner, Juergen J.; Maikowske, Stefan; Vittoriosi, Alice

    Evaporation of liquids is of major interest for many topics in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of superheated steam is mandatory for numerous processes. Generally, this is performed by use of classical pool boiling and evaporation process equipment. Another possibility is creating mixtures of gases and liquids, combined with a heating of this haze. Both methods provide relatively limited performance. Due to the advantages of microstructure devices especially in chemical process engineering [1] the interest in microstructure evaporators and steam generators have been increased through the last decade. In this publication several microstructure devices used for evaporation and generation of steam as well as superheating will be described. Here, normally electrically powered devices containing micro channels as well as non-channel microstructures are used due to better controllability of the temperature level. Micro channel heat exchangers have been designed, manufactured and tested at the Institute for Micro Process Engineering of the Karlsruhe Institute of Technology for more than 15 years. Starting with the famous Karlsruhe Cube, a cross-flow micro channel heat exchanger of various dimensions, not only conventional heat transfer between liquids or gases have been theoretically and experimentally examined but also phase transition from liquids to gases (evaporation) and condensation of liquids. However, the results obtained with sealed microstructure devices have often been unsatisfying. Thus, to learn more onto the evaporation process itself, an electrically powered device for optical inspection of the microstructures and the processes inside has been designed and manufactured [2]. This was further optimized and improved for better controllability and reliable experiments [3]. Exchangeable metallic micro channel array foils as well as an optical inspection of the evaporation process by

  17. Modeling evaporation from spent nuclear fuel storage pools: A diffusion approach

    NASA Astrophysics Data System (ADS)

    Hugo, Bruce Robert

    Accurate prediction of evaporative losses from light water reactor nuclear power plant (NPP) spent fuel storage pools (SFPs) is important for activities ranging from sizing of water makeup systems during NPP design to predicting the time available to supply emergency makeup water following severe accidents. Existing correlations for predicting evaporation from water surfaces are only optimized for conditions typical of swimming pools. This new approach modeling evaporation as a diffusion process has yielded an evaporation rate model that provided a better fit of published high temperature evaporation data and measurements from two SFPs than other published evaporation correlations. Insights from treating evaporation as a diffusion process include correcting for the effects of air flow and solutes on evaporation rate. An accurate modeling of the effects of air flow on evaporation rate is required to explain the observed temperature data from the Fukushima Daiichi Unit 4 SFP during the 2011 loss of cooling event; the diffusion model of evaporation provides a significantly better fit to this data than existing evaporation models.

  18. Building micro-soccer-balls with evaporating colloidal fakir drops

    NASA Astrophysics Data System (ADS)

    Gelderblom, Hanneke; Marín, Álvaro G.; Susarrey-Arce, Arturo; van Housselt, Arie; Lefferts, Leon; Gardeniers, Han; Lohse, Detlef; Snoeijer, Jacco H.

    2013-11-01

    Drop evaporation can be used to self-assemble particles into three-dimensional microstructures on a scale where direct manipulation is impossible. We present a unique method to create highly-ordered colloidal microstructures in which we can control the amount of particles and their packing fraction. To this end, we evaporate colloidal dispersion drops from a special type of superhydrophobic microstructured surface, on which the drop remains in Cassie-Baxter state during the entire evaporative process. The remainders of the drop consist of a massive spherical cluster of the microspheres, with diameters ranging from a few tens up to several hundreds of microns. We present scaling arguments to show how the final particle packing fraction of these balls depends on the drop evaporation dynamics, particle size, and number of particles in the system.

  19. Evaporating Spray in Supersonic Streams Including Turbulence Effects

    NASA Technical Reports Server (NTRS)

    Balasubramanyam, M. S.; Chen, C. P.

    2006-01-01

    Evaporating spray plays an important role in spray combustion processes. This paper describes the development of a new finite-conductivity evaporation model, based on the two-temperature film theory, for two-phase numerical simulation using Eulerian-Lagrangian method. The model is a natural extension of the T-blob/T-TAB atomization/spray model which supplies the turbulence characteristics for estimating effective thermal diffusivity within the droplet phase. Both one-way and two-way coupled calculations were performed to investigate the performance of this model. Validation results indicate the superiority of the finite-conductivity model in low speed parallel flow evaporating sprays. High speed cross flow spray results indicate the effectiveness of the T-blob/T-TAB model and point to the needed improvements in high speed evaporating spray modeling.

  20. Structural and evaporative evolutions in desiccating sessile drops of blood

    NASA Astrophysics Data System (ADS)

    Sobac, B.; Brutin, D.

    2011-07-01

    We report an experimental investigation of the drying of a deposited drop of whole blood. Flow motion, adhesion, gelation, and fracturation all occur during the evaporation of this complex matter, leading to a final typical pattern. Two distinct regimes of evaporation are highlighted: the first is driven by convection, diffusion, and gelation in a liquid phase, whereas the second, with a much slower rate of evaporation, is characterized by the mass transport of the liquid left over in the gellified biocomponent matter. A diffusion model of the drying process allows a prediction of the transition between these two regimes of evaporation. Moreover, the formation of cracks and other events occurring during the drying are examined and shown to be driven by critical solid mass concentrations.

  1. Quantum dynamics of charge state in silicon field evaporation

    NASA Astrophysics Data System (ADS)

    Silaeva, Elena P.; Uchida, Kazuki; Watanabe, Kazuyuki

    2016-08-01

    The charge state of an ion field-evaporating from a silicon-atom cluster is analyzed using time-dependent density functional theory coupled to molecular dynamics. The final charge state of the ion is shown to increase gradually with increasing external electrostatic field in agreement with the average charge state of silicon ions detected experimentally. When field evaporation is triggered by laser-induced electronic excitations the charge state also increases with increasing intensity of the laser pulse. At the evaporation threshold, the charge state of the evaporating ion does not depend on the electrostatic field due to the strong contribution of laser excitations to the ionization process both at low and high laser energies. A neutral silicon atom escaping the cluster due to its high initial kinetic energy is shown to be eventually ionized by external electrostatic field.

  2. PILOT-SCALE TEST RESULTS OF A THIN FILM EVAPORATOR SYSTEM FOR MANAGEMENT OF LIQUID HIGH-LEVEL WASTES AT THE HANFORD SITE WASHINGTON USA -11364

    SciTech Connect

    CORBETT JE; TEDESCH AR; WILSON RA; BECK TH; LARKIN J

    2011-02-14

    A modular, transportable evaporator system, using thin film evaporative technology, is planned for deployment at the Hanford radioactive waste storage tank complex. This technology, herein referred to as a wiped film evaporator (WFE), will be located at grade level above an underground storage tank to receive pumped liquids, concentrate the liquid stream from 1.1 specific gravity to approximately 1.4 and then return the concentrated solution back into the tank. Water is removed by evaporation at an internal heated drum surface exposed to high vacuum. The condensed water stream will be shipped to the site effluent treatment facility for final disposal. This operation provides significant risk mitigation to failure of the aging 242-A Evaporator facility; the only operating evaporative system at Hanford maximizing waste storage. This technology is being implemented through a development and deployment project by the tank farm operating contractor, Washington River Protection Solutions (WRPS), for the Office of River Protection/Department of Energy (ORPIDOE), through Columbia Energy and Environmental Services, Inc. (Columbia Energy). The project will finalize technology maturity and install a system at one of the double-shell tank farms. This paper summarizes results of a pilot-scale test program conducted during calendar year 2010 as part of the ongoing technology maturation development scope for the WFE.

  3. Tubular sublimatory evaporator heat sink

    NASA Technical Reports Server (NTRS)

    Webbon, B. W. (Inventor)

    1977-01-01

    An evaporative refrigerator or cooler comprising a bundle of spaced, porous walled tubes closed at one of their ends and vented to a vacuum at the other end is disclosed. The tube bundle is surrounded by a water jacket having a hot water inlet distribution manifold and a cooled water outlet through a plenum chamber. Hot water is pumped into the jacket to circulate around the tubes, and when this water meets the vacuum existing inside the tubes, it evaporates thereby cooling the water in the jacket. If cooling proceeds to the point where water penetrating or surrounding all or part of the tubes freezes, operation continues with local sublimation of the ice on the tubes while the circulating water attempts to melt the ice. Both sublimation and evaporation may take place simultaneously in different regions of the device.

  4. Evaporation duct communication: Test Plan

    NASA Astrophysics Data System (ADS)

    Anderson, K. D.

    1991-02-01

    The Evaporation Duct Communication (EDCOM) project is an effort to provide an alternative ship-to-ship communications channel using the natural environment. A microwave communication link can be used on an over-the-water, over-the-horizon path through the evaporation duct. This report shows how a microwave communication link, operating at a range separation of more than twice the line-of-sight range, can be constructed. This link can achieve about 80-percent availability at a transmission frequency of 14.5 GHz and can be constructed using off-the-shelf RF equipment. Operation of this link will provide the first set of measurements of channel capacity that can be critically dependent on the existence of an oceanic evaporation duct. Construction of this link presents a unique opportunity to study and evaluate an alternative communications channel that can be used to alleviate naval battlegroup communications load.

  5. Evaporation of primordial black holes

    NASA Astrophysics Data System (ADS)

    Hawking, S. W.

    The usual explanation of the isotropy of the universe is that inflation would have smoothed out any inhomogeneities. However, if the universe was initially fractal or in a foam like state, an overall inflation would have left it in the same state. I suggest that the universe did indeed begin with a tangled web of wormholes connecting pairs of black holes but that the inflationary expansion was unstable: wormholes that are slightly smaller correspond to black holes that are hotter than the cosmological background and evaporate away. This picture is supported by calculations with Raphael Bousso of the evaporation of primordial black holes in the s-wave and large N approximations.

  6. Evaporation of Sessile Droplets Laden with Particles and Insoluble Surfactants.

    PubMed

    Karapetsas, George; Chandra Sahu, Kirti; Matar, Omar K

    2016-07-12

    We consider the flow dynamics of a thin evaporating droplet in the presence of an insoluble surfactant and noninteracting particles in the bulk. On the basis of lubrication theory, we derive a set of evolution equations for the film height, the interfacial surfactant, and bulk particle concentrations, taking into account the dependence of liquid viscosity on the local particle concentration. An important ingredient of our model is that it takes into account the fact that the surfactant adsorbed at the interface hinders evaporation. We perform a parametric study to investigate how the presence of surfactants affects the evaporation process as well as the flow dynamics with and without the presence of particles in the bulk. Our numerical calculations show that the droplet lifetime is affected significantly by the balance between the ability of the surfactant to enhance spreading, suppressing the effect of thermal Marangoni stresses-induced motion, and to hinder the evaporation flux through the reduction of the effective interfacial area of evaporation, which tend to accelerate and decelerate the evaporation process, respectively. For particle-laden droplets and in the case of dilute solutions, the droplet lifetime is found to be weakly dependent on the initial particle concentration. We also show that the particle deposition patterns are influenced strongly by the direct effect of the surfactant on the evaporative flux; in certain cases, the "coffee-stain" effect is enhanced significantly. A discussion of the delicate interplay between the effects of capillary pressure and solutal and thermal Marangoni stresses, which drive the liquid flow inside of the evaporating droplet giving rise to the observed results, is provided herein. PMID:27300638

  7. Waste Evaporator Accident Simulation Using RELAP5 Computer Code

    SciTech Connect

    POLIZZI, L.M.

    2004-04-28

    An evaporator is used on liquid waste from processing facilities to reduce the volume of the waste through heating the waste and allowing some of the water to be separated from the waste through boiling. This separation process allows for more efficient processing and storage of liquid waste. Commonly, the liquid waste consists of an aqueous solution of chemicals that over time could induce corrosion, and in turn weaken the tubes in the steam tube bundle of the waste evaporator that are used to heat the waste. This chemically induced corrosion could escalate into a possible tube leakage and/or the severance of a tube(s) in the tube bundle. In this paper, analyses of a waste evaporator system for the processing of liquid waste containing corrosive chemicals are presented to assess the system response to this accident scenario. This accident scenario is evaluated since its consequences can propagate to a release of hazardous material to the outside environment. It is therefore important to ensure that the evaporator system component structural integrity is not compromised, i.e. the design pressure and temperature of the system is not exceeded during the accident transient. The computer code used for the accident simulation is RELAP5-MOD31. The accident scenario analyzed includes a double-ended guillotine break of a tube in the tube bundle of the evaporator. A mitigated scenario is presented to evaluate the excursion of the peak pressure and temperature in the various components of the evaporator system to assess whether the protective actions and controls available are adequate to ensure that the structural integrity of the evaporator system is maintained and that no atmospheric release occurs.

  8. On the theory relating changes in area-average and pan evaporation (Invited)

    NASA Astrophysics Data System (ADS)

    Shuttleworth, W.; Serrat-Capdevila, A.; Roderick, M. L.; Scott, R.

    2009-12-01

    Theory relating changes in area-average evaporation with changes in the evaporation from pans or open water is developed. Such changes can arise by Type (a) processes related to large-scale changes in atmospheric concentrations and circulation that modify surface evaporation rates in the same direction, and Type (b) processes related to coupling between the surface and atmospheric boundary layer (ABL) at the landscape scale that usually modify area-average evaporation and pan evaporation in different directions. The interrelationship between evaporation rates in response to Type (a) changes is derived. They have the same sign and broadly similar magnitude but the change in area-average evaporation is modified by surface resistance. As an alternative to assuming the complementary evaporation hypothesis, the results of previous modeling studies that investigated surface-atmosphere coupling are parameterized and used to develop a theoretical description of Type (b) coupling via vapor pressure deficit (VPD) in the ABL. The interrelationship between appropriately normalized pan and area-average evaporation rates is shown to vary with temperature and wind speed but, on average, the Type (b) changes are approximately equal and opposite. Long-term Australian pan evaporation data are analyzed to demonstrate the simultaneous presence of Type (a) and (b) processes, and observations from three field sites in southwestern USA show support for the theory describing Type (b) coupling via VPD. England's victory over Australia in 2009 Ashes cricket test match series will not be mentioned.

  9. Evaporation of nebular fines during chondrule formation

    NASA Astrophysics Data System (ADS)

    Wasson, John T.

    2008-06-01

    temperatures is kinetically inhibited, radiation associated with chondrule formation would have accelerated the conversion. There is now evidence that an appreciable fraction of the nanodiamonds previously held to be presolar were actually formed in the solar nebula. Industrial condensation of diamonds from mixtures of CH 4 and H 2 implies that high nebular CH 4/CO ratios favored nanodiamond formation. A large fraction of chondritic insoluble organic matter may have formed in related processes. At low nebular temperatures appreciable water should have been incorporated into the smoke that condensed following dust (and some chondrule) evaporation. If chondrule formation continued down to temperatures as low as 250 K this process could account for the water concentration observed in primitive chondrites such as LL3.0 and CO3.0 chondrites. Higher H 2O contents in CM and CI chondrites may reflect asteroidal redistribution. In some chondrite groups (e.g., CR) the Mg/Si ratio of matrix material is appreciably (30%) lower than that of chondrules but the bulk Mg/Si ratio is roughly similar to the CI or solar ratio. This has been interpreted as a kind of closed-system behavior sometimes called "complementarity." This leads to the conclusion that nebular fines were efficiently agglomerated. Its importance, however is obscured by the observation that bulk Mg/Si ratios in ordinary and enstatite chondrites are much lower than those in carbonaceous chondrites, and thus that complementarity did not hold throughout the solar nebula.

  10. Forced-Flow Evaporative Cooler

    NASA Technical Reports Server (NTRS)

    Ellis, Wilbert E.; Niggemann, Richard E.

    1987-01-01

    Evaporative cooler absorbs heat efficiently under unusual gravitational conditions by using centrifugal force and vapor vortexes to maintain good thermal contact between heat-transfer surface and vaporizable coolant. System useful for cooling electronic or other equipment under low gravity encountered in spacecraft or under multiple-gravity conditions frequently experienced in high-performance airplanes.

  11. Simulation of a refrigerant evaporator

    NASA Astrophysics Data System (ADS)

    Vandermeer, Jakob Stefanus

    A computer model for the design and optimization of the compressor refrigeration cycle especially with respect to dynamic behavior was developed. A steady state version was also developed. The model describing the refrigerant is divided into the evaporation and superheating regions. A mechanism based on empirics corrects the model for the influence of transportation times in the evaporation region. The mass balance of the refrigerant in the superheat region is regarded as quasi-static, because of the small mass of the vapor. The energy balance accounts for a distributed model and is represented by the steady state solution of the partial differential equation which describes this area for the steady conditions. A correction for the dynamical effects was added to this solution, for all influencing parameters, according to the analytical dynamic solution for the case of the evaporation temperature as input parameter. The expansion device model was worked out for the usual type of device in combination with a dry evaporator, the thermostatic expansion valve. Validation tests are described.

  12. Micromachined evaporators for AMTEC cells

    SciTech Connect

    Izenson, M.G.; Crowley, C.J.

    1996-12-31

    To achieve high cell efficiency and reliability, the capillary pumping system for Alkali Metal Thermal to Electric Conversion (AMTEC) must have three key characteristics: (1) very small pores to achieve a high capillary pumping head, (2) high permeability for the flow of liquid sodium to minimize internal losses, and (3) be made from a material that is exceptionally stable at high temperatures in a sodium environment. The authors have developed micromachining techniques to manufacture high performance evaporators for AMTEC cells. The evaporators have been fabricated from stainless steel, molybdenum, and a niobium alloy (Nb-1Zr). The regular, micromachined structure leads to very high capillary pumping head with high permeability for liquid flow. Data from tests performed with common fluids at room temperature characterize the capillary pumping head and permeability of these structures. Three micromachined evaporators have been built into AMTEC cells and operated at temperatures up to 1,100 K. Results from these tests confirm the excellent pumping capabilities of the micromachined evaporators.

  13. Membrane evaporator/sublimator investigation

    NASA Technical Reports Server (NTRS)

    Elam, J.; Ruder, J.; Strumpf, H.

    1974-01-01

    Data are presented on a new evaporator/sublimator concept using a hollow fiber membrane unit with a high permeability to liquid water. The aim of the program was to obtain a more reliable, lightweight and simpler Extra Vehicular Life Support System (EVLSS) cooling concept than is currently being used.

  14. Diffusion and evaporation of a liquid droplet

    NASA Astrophysics Data System (ADS)

    Shukla, K. N.

    1980-06-01

    The process of evaporation and diffusion of a spherical liquid droplet in an atmosphere of noncondensable gas is studied theoretically. An equation for the shrinkage of the radius of the droplet is derived on the basis of continuity and momentum equations. Further, a conjugate problem consisting of the energy and mass balance for the gaseous environment is formulated. An approximation of thin thermal and diffusion boundary-layers is introduced to simplify the analysis. Results are presented for methanol-nitrogen, ammonia-nitrogen, and sodium-argon systems. It has been observed that the droplet of highly viscous fluid exhibits rapid contraction.

  15. Recovery of boric acid from evaporator concentrates

    SciTech Connect

    Chrubasik, A.; Hennecke, A.; Chechelnitzky, G.M.; Kremnev, V.A.; Sinjawski, P.N.; Tevestchenko, L.J.

    1995-12-31

    The process is based on such characteristic properties of boric acid and borates as: solubility depending on pH-value; and high ion-exchange resin capacity for borates and its regeneration by means of ammonia solution. On the basis of laboratory investigations a pilot plant BOR 100 was built 1993. The operation of the pilot plant started at the beginning of 1994. After the functional test and start up in the first half year 1994 the treatment of few batches of original evaporator concentrates was performed.

  16. Evaporation dynamics of femtoliter water capillary bridges

    NASA Astrophysics Data System (ADS)

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Kim, Jung Gu; Weon, Byung Mook

    2015-11-01

    Capillary bridges are usually formed by a small liquid volume in confined space between two solid surfaces and particularly they have lower internal pressure than 1 atm at femtoliter scales. Femtoliter capillary bridges exhibit rapid evaporation rates. To quantify detailed evaporation kinetics of femtoliter bridges, we present a feasible protocol to directly visualize femtoliter water bridges that evaporate in still air between a microsphere and a flat substrate by utilizing transmission X-ray microscopy. Precise measurements of evaporation kinetics for water bridges indicate that lower water pressure than 1 atm can significantly decelerate evaporation by suppression of vapor diffusion. This finding would provide a consensus to understand evaporation of ultrasmall capillary bridges.

  17. GLEAM version 3: Global Land Evaporation Datasets and Model

    NASA Astrophysics Data System (ADS)

    Martens, B.; Miralles, D. G.; Lievens, H.; van der Schalie, R.; de Jeu, R.; Fernandez-Prieto, D.; Verhoest, N.

    2015-12-01

    Terrestrial evaporation links energy, water and carbon cycles over land and is therefore a key variable of the climate system. However, the global-scale magnitude and variability of the flux, and the sensitivity of the underlying physical process to changes in environmental factors, are still poorly understood due to limitations in in situ measurements. As a result, several methods have risen to estimate global patterns of land evaporation from satellite observations. However, these algorithms generally differ in their approach to model evaporation, resulting in large differences in their estimates. One of these methods is GLEAM, the Global Land Evaporation: the Amsterdam Methodology. GLEAM estimates terrestrial evaporation based on daily satellite observations of meteorological variables, vegetation characteristics and soil moisture. Since the publication of the first version of the algorithm (2011), the model has been widely applied to analyse trends in the water cycle and land-atmospheric feedbacks during extreme hydrometeorological events. A third version of the GLEAM global datasets is foreseen by the end of 2015. Given the relevance of having a continuous and reliable record of global-scale evaporation estimates for climate and hydrological research, the establishment of an online data portal to host these data to the public is also foreseen. In this new release of the GLEAM datasets, different components of the model have been updated, with the most significant change being the revision of the data assimilation algorithm. In this presentation, we will highlight the most important changes of the methodology and present three new GLEAM datasets and their validation against in situ observations and an alternative dataset of terrestrial evaporation (ERA-Land). Results of the validation exercise indicate that the magnitude and the spatiotemporal variability of the modelled evaporation agree reasonably well with the estimates of ERA-Land and the in situ

  18. Inundation and groundwater dynamics for quantification of evaporative water loss in tropical wetlands

    NASA Astrophysics Data System (ADS)

    Schwerdtfeger, J.; Johnson, M. S.; Couto, E. G.; Amorim, R. S. S.; Sanches, L.; Campelo Júnior, J. H.; Weiler, M.

    2014-04-01

    The remoteness, complexity and heterogeneity of tropical wetlands make the characterisation of their hydrological processes challenging. In particular estimates of evaporative water loss are inherently uncertain. In view of the large influence on the local and regional climate, the quantification of evaporation is essential for the determination of the water balance of permanent and intermittent water bodies. Data for tropical wetlands are scarce where their remoteness impedes direct evaporation measurements. Seasonal inundation dynamics affect evaporation processes in tropical wetlands, which can be analysed in two stages: the first stage during the wet season and the second stage during the dry season. As yet no adequate method exists for determining second stage evaporation without soil moisture data, which are usually unavailable for the remote tropical wetlands. Our study aimed at developing a process-based model to simulate first and second stage evaporation in tropical wetlands. We selected a set of empirical potential evaporation (PET) models of varying complexity, each based on different assumptions and available datasets, and evaluated the models with pan evaporation observations in the Pantanal of South America, one of the largest tropical wetlands in the world. We used high-resolution measurements of surface and groundwater levels at different locations to determine the water available for evaporation. Actual evaporation (AET) was derived by constraining simulated PET based on available water. The model of best fit was applied to different types of water bodies with varying inundation durations and captured first and second stage evaporation. With our new model we could quantify evaporative water loss in the dry and the wet season for different locations in the Pantanal. This new spatially-explicit approach represents an improvement in our understanding of the role of evaporation in the water balance of the Pantanal. We recommend the application of this

  19. Inundation and groundwater dynamics for quantification of evaporative water loss in tropical wetlands

    NASA Astrophysics Data System (ADS)

    Schwerdtfeger, J.; Johnson, M. S.; Couto, E. G.; Amorim, R. S. S.; Sanches, L.; Campelo, J. H., Jr.; Weiler, M.

    2014-11-01

    Characterizing hydrological processes within tropical wetlands is challenging due to their remoteness, complexity and heterogeneity. In particular, estimates of evaporative water loss are inherently uncertain. In view of the large influence on the local and regional climate, the quantification of evaporation is essential for the determination of the water balance of permanent and intermittent water bodies. Data for tropical wetlands are scarce where their remoteness impedes direct evaporation measurements. Seasonal inundation dynamics affect evaporation processes in tropical wetlands, which can be analysed in two stages: the first stage during the wet season and the second stage during the dry season. As yet no adequate method exists for determining second-stage evaporation in a data-scarce environment that additionally allows for a transfer of simulated actual evaporation (AET) to other locations. Our study aimed at developing a process-based model to simulate first- and second-stage evaporation in tropical wetlands. We selected a set of empirical potential evaporation (PET) models of varying complexity, each based on different assumptions and available data sets, and evaluated the models with pan evaporation observations in the Pantanal of South America, one of the largest tropical wetlands in the world. We used high-resolution measurements of surface and groundwater levels at different locations to determine the water available for evaporation. AET was derived by constraining simulated PET based on available water. The model of best fit was applied to different types of water bodies with varying hydroperiods to capture first- and second-stage evaporation across a range of wetland types. With our new model we could quantify evaporative water loss in the dry and the wet season for different locations in the Pantanal. This new spatially explicit approach represents an improvement in our understanding of the role of evaporation in the water balance of the Pantanal

  20. Isotopic Compositions of Evaporative Fluxes

    NASA Astrophysics Data System (ADS)

    Feng, X.; Lauder, A. M.; Kopec, B. G.; Dade, W. B.; Virginia, R. A.; Posmentier, E. S.

    2013-12-01

    The isotopic fluxes of evaporation from a water surface are typically computed using a one-dimensional model, originally conceptualized by Craig and Gordon (1965) and further developed and adapted to different natural settings (such as transpiration, open surface evaporation, etc.) by various investigators. These models have two distinguishing characteristics. First, there exists a laminar layer where molecular diffusion away from the water-air interface causes kinetic isotopic fractionation. The magnitude of this fractionation is controlled by the diffusion/transport coefficient of each vapor isotopologue in air and their concentration gradients, the latter being controlled by relative humidity, isotopic ratios of ambient air, and turbulent conditions (such as wind and surface roughness). Second, the horizontal variations are ignored. In particular, the effect of horizontal advection on isotopic variations in the ambient air is not considered. The research reported here addresses the effects of relinquishing the simplifying assumptions in both of these areas. We developed a model, in which the simplification of a purely laminar layer is dropped. Instead, we express the vertical transport coefficient as the sum of the molecular diffusivity, that differs for each water isotopologue, and the turbulent diffusivity that increases linearly with height but does not vary among water isotopologues. With this model, the kinetic isotopic effect reduces with height in the vicinity of the water surface, and the net isotopic fractionation through the boundary layer can be integrated. The advantage of this conceptualization is that the magnitude of kinetic isotopic fractionation can be assessed directly with changing environmental conditions, such as humidity and wind speed, rather than approximated by discontinuous empirical functions of the environmental conditions, as in the conventional models mentioned above. To address the effect of lateral heterogeneity, we expanded the

  1. Quantifying Evaporation in a Permeable Pavement System

    EPA Science Inventory

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. Th...

  2. Analysis of energy use in tomato evaporation

    SciTech Connect

    Rumsey, T.; Conant, T.

    1980-01-01

    Field performance data for four tomato product evaporators are presented and analyzed. Steam and feed flow rates along with steam economies were measured and are compared to steady state theoretical evaporator models.

  3. A numerical simulation of heat transfer in evaporative cooling towers

    NASA Astrophysics Data System (ADS)

    Benton, D. J.

    1983-09-01

    A phenomenological analysis was developed for the processes which occur within an evaporative cooling tower. The analysis includes the basic principles of mass, momentum, and energy conservation and empirical elationships for component characteristics such as transfer and pressure drop coefficients. A computer model which simulates the processes occurring in evaporative cooling towers was developed. The results of this computer model are compared to field data to verify the analysis and the computer modeling. The computer model may be used to analyze the performance of existing towers or to predict the performance of alternative tower designs.

  4. Evaporative cooling in microfluidic channels

    NASA Astrophysics Data System (ADS)

    Maltezos, George; Rajagopal, Aditya; Scherer, Axel

    2006-08-01

    Evaporative cooling is an effective and energy efficient way to rapidly remove heat from a system. Specifically, evaporative cooling in microfluidic channels can provide a cost-effective solution for the cooling of electronic devices and chemical reactors. Here we present microfluidic devices fabricated by using soft-lithography techniques to form simple fluidic junctions between channels carrying refrigerant and channels carrying N2 gas. The effects of channel geometry and delivery pressure on the performance of refrigeration through vaporization of acetone, isopropyl alcohol, and ethyl ether were characterized. By varying gas inlet pressures, refrigerants, and angles of the microfluidic junctions, optimal cooling conditions were found. Refrigeration rates in excess of 40°C/s were measured, and long lasting subzero cooling in the junction could be observed.

  5. 21 CFR 131.130 - Evaporated milk.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Evaporated milk. 131.130 Section 131.130 Food and... CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.130 Evaporated milk. (a) Description. Evaporated milk is the liquid food obtained by partial removal of water only from milk....

  6. SEWAGE DISPOSAL BY EVAPORATION-TRANSPIRATION

    EPA Science Inventory

    One of the methods for on-site disposal of wastewater from individual homes is by evaporation. Two types of evaporative disposal systems have been investigated in this study; evapo-transpiration (ET) beds and mechanical evaporation units. Twenty nine test lysimeters of 0.22 cubic...

  7. Use of microwave-assisted evaporation for the complete recovery of volatile species of inorganic trace analytes

    PubMed

    Link; Kingston

    2000-07-01

    Solutions must often be evaporated prior to analysis either to preconcentrate the analyte or to eliminate an incompatible matrix component. Elimination of the halogen-based acids HCI and HF using traditional evaporation methods poses recovery problems because of volatilization of the target analyte as the chloride or fluoride species. A new sample preparation chemistry for trace analysis, where losses of analyte due to volatilization during the evaporation process are minimized, is explored using the unique heating mechanisms of the microwave-assisted evaporation process. The heating mechanisms of hot plate evaporation and microwave-assisted evaporation are compared, and temperatures throughout the evaporation process using each method are predicted and experimentally verified. Because the solution actually cools during microwave-assisted evaporation, volatilization due to overheating at dryness is minimized. Elemental standard solutions and SRM soil and tissue digestates were evaporated using a hot plate method and a newly developed reduced-pressure microwave-assisted evaporation apparatus. Redissolution and analysis of the residue by ICPMS showed that complete recovery was achieved using microwave-assisted evaporation while losses of several classically volatile analytes occurred using hot plate evaporation. PMID:10905326

  8. Evaporation by mechanical vapor recompression

    NASA Astrophysics Data System (ADS)

    Iverson, C. H.; Coury, G. E.

    1980-04-01

    Progress in the development of a study of the application of the technologies of mechanical vapor recompression and falling film evaporation as applied to the beet sugar industry is reported. Progress is reported in the following areas: technical literature search; report on visit to European factories using these technologies; energy balance studies of factories offered by the industry as candidates for the demonstration plants; and report on energy balance studies and the recommendations as to the site for the demonstration plant.

  9. Dynamics of evaporative colloidal patterning

    NASA Astrophysics Data System (ADS)

    Kaplan, C. Nadir; Wu, Ning; Mandre, Shreyas; Aizenberg, Joanna; Mahadevan, L.

    2015-09-01

    Drying suspensions often leave behind complex patterns of particulates, as might be seen in the coffee stains on a table. Here, we consider the dynamics of periodic band or uniform solid film formation on a vertical plate suspended partially in a drying colloidal solution. Direct observations allow us to visualize the dynamics of band and film deposition, where both are made of multiple layers of close packed particles. We further see that there is a transition between banding and filming when the colloidal concentration is varied. A minimal theory of the liquid meniscus motion along the plate reveals the dynamics of the banding and its transition to the filming as a function of the ratio of deposition and evaporation rates. We also provide a complementary multiphase model of colloids dissolved in the liquid, which couples the inhomogeneous evaporation at the evolving meniscus to the fluid and particulate flows and the transition from a dilute suspension to a porous plug. This allows us to determine the concentration dependence of the bandwidth and the deposition rate. Together, our findings allow for the control of drying-induced patterning as a function of the colloidal concentration and evaporation rate.

  10. Nonmagnetic impellers improve evaporative cooling

    SciTech Connect

    Hausman, T. )

    1993-03-01

    This article describes how nonmagnetic impeller flow sensors help improve efficiency of open evaporative cooling water systems. Open evaporative cooling water systems provide economical heat sinks with efficient reuse of water. However, their water loss through evaporation, though minimal, results in an increased concentration of dissolved and suspended impurities in the remaining water. To deconcentrate the water and minimize impurities, the system water is bled off and replaced with fresh makeup water. Bleedoff helps, but to maintain efficient operation and protect the system from water-related catastrophes, various chemical treatments are required for the control of corrosion, deposition, and biological growth. Efficient addition of makeup water and chemical additives can be achieved by a system design employing multiple data points, using flow sensors having high reproducibility for good trend data. In such a system, nonmagnetic flow sensors provide 1% accuracy and excellent reproducibility. In addition, their low initial cost and long service life mean that they can be used cost effectively at multiple data collection points to eliminate approximations.

  11. Hollow-Fiber Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Settles, Joseph

    2013-01-01

    The hollow-fiber spacesuit water membrane evaporator (HoFi SWME) is being developed to perform the thermal control function for advanced spacesuits and spacecraft to take advantage of recent advances in micropore membrane technology in providing a robust, heat-rejection device that is less sensitive to contamination than is the sublimator. After recent contamination tests, a commercial-off-the-shelf (COTS) micro porous hollow-fiber membrane was selected for prototype development as the most suitable candidate among commercial hollow-fiber evaporator alternatives. An innovative design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was developed into a full-scale prototype for the spacesuit application. Vacuum chamber testing has been performed to characterize heat rejection as a function of inlet water temperature and water vapor back-pressure, and to show contamination resistance to the constituents expected to be found in potable water produced by the wastewater reclamation distillation processes. Other tests showed tolerance to freezing and suitability to reject heat in a Mars pressure environment. In summary, HoFi SWME is a lightweight, compact evaporator for heat rejection in the spacesuit that is robust, contamination- insensitive, freeze-tolerant, and able to reject the required heat of spacewalks in microgravity, lunar, and Martian environments. The HoFi is packaged to reject 810 W of heat through 800 hours of use in a vacuum environment, and 370 W in a Mars environment. The device also eliminates free gas and dissolved gas from the coolant loop.

  12. Comparison of evaporation duct and path loss models

    NASA Astrophysics Data System (ADS)

    Patterson, Wayne L.

    1985-09-01

    This paper will evaluate the current meteorological measurement techniques used to infer the evaporation-ducting process. Included within this study is a comparison of relative performance, sensitivities to meteorological inputs, and ease of computation for three standard evaporation duct models and two electromagnetic wave propagation models. The evaporation duct models performed reasonably and equally well when considering statistically averaged meteorological inputs, but all were extremely sensitive to point-observed meteorological input parameters. The measurement techniques employed by naval and transiting commercial vessels are not of sufficient quality to infer adequately the evaporation-ducting process. The theory behind calculation of path loss values based upon current evaporation duct inputs is statistically sound. For studies of propagation phenomena or development of electromagnetic systems, both of the compared models perform reasonably well and are accurate predictors. However, the use of either model for estimation of a single propagation range based upon a point meteorological observation is severely limited by the accuracy of the data.

  13. Estimating daily pan evaporation using adaptive neural-based fuzzy inference system

    NASA Astrophysics Data System (ADS)

    Keskin, M. Erol; Terzi, Özlem; Taylan, Dilek

    2009-09-01

    Estimation of evaporation is important for water planning, management, and hydrological practices. There are many available methods to estimate evaporation from a water surface, comprising both direct and indirect methods. All the evaporation models are based on crisp conceptions with no uncertainty element coupled into the model structure although in daily evaporation variations there are uncontrollable effects to a certain extent. The probabilistic, statistical, and stochastic approaches require large amounts of data for the modeling purposes and therefore are not practical in local evaporation studies. It is therefore necessary to adopt a better approach for evaporation modeling, which is the fuzzy sets and adaptive neural-based fuzzy inference system (ANFIS) as used in this paper. ANFIS and fuzzy sets have been evaluated for its applicability to estimate evaporation from meteorological data which is including air and water temperatures, solar radiation, and air pressure obtained from Automated GroWheather meteorological station located near Lake Eğirdir and daily pan evaporation values measured by XVIII. District Directorate of State Hydraulic Works. Results of ANFIS and fuzzy logic approaches were analyzed and compared with measured daily pan evaporation values. ANFIS approach could be employed more successfully in modeling the evaporation process than fuzzy sets.

  14. Evaporator Development for an Evaporative Heat Pipe System

    NASA Technical Reports Server (NTRS)

    Peters, Leigh C.

    2004-01-01

    As fossil fuel resources continue to deplete, research for alternate power sources continues to develop. One of these alternate technologies is fuel cells. They are a practical fuel source able to provide significant amounts of power for applications from laptops to automobiles and their only byproduct is water. However, although this technology is over a century old and NASA has been working with it since the early 1960 s there is still room for improvement. The research I am involved in at NASA's Glenn Research Center is focusing on what is called a regenerative fuel cell system. The unique characteristic of this type of system is that it used an outside power source to create electrolysis of the water it produces and it then reuses the hydrogen and oxygen to continue producing power. The advantage of this type of system is that, for example, on space missions it can use solar power to recharge its gas supplies between periods when the object being orbited blocks out the sun. This particular system however is far from completion. This is because of the many components that are required to make up a fuel cell that need to be tested individually. The specific part of the system that is being worked on this summer of 2004 is the cooling system. The fuel cell stack, that is the part that actually creates the power, also produces a lot of heat. When not properly cooled, it has been known to cause fires which, needless to say are not conducive to the type of power that is trying to be created. In order to cool the fuel cell stack in this system we are developing a heat pipe cooling system. One of the main components of a heat pipe cooling system is what is known as the evaporator, and that is what happens to be the part of the system we are developing this summer. In most heat pipe systems the evaporator is a tube in which the working fluid is cooled and then re-circulated through the system to absorb more heat energy from the fuel cell stack. For this system, instead

  15. NWCF Evaporator Tank System 2001 Offgas Emissions Inventory

    SciTech Connect

    Boardman, R.D.; Lamb, K.M.; Matejka, L.A.; Nenni, J.A.

    2002-02-27

    An offgas emissions inventory and liquid stream characterization of the Idaho New Waste Calcining Facility (NWCF) Evaporator Tank System (ETS), formerly known as the High Level Liquid Waste Evaporator (HLLWE), has been completed. The emissions rates of volatile and semi-volatile organic compounds, multiple metals, particulate, and hydrochloric acid were measured in accordance with an approved Quality Assurance Project Plan (QAPjP) and Test Plan that invoked U.S. Environmental Protection Agency (EPA) standard sample collection and analysis procedures. Offgas samples were collected during the start up and at the end of evaporator batches when it was hypothesized the emissions would be at peak rates. Corresponding collection of samples from the evaporator feed overhead condensate, and bottoms was made at approximately the same time as the emissions inventory to support material balance determinations for the evaporator process. The data indicate that organic compound emissions are slightly higher at the beginning of the batch while metals emissions, including mercury, are slightly higher at the end of the evaporator batch. The maximum emissions concentrations are low for all constituents of primary concern. Mercury emissions were less than 5 ppbv, while the sum of HCl and Cl2 emissions was less than 1 ppmv. The sum of all organic emissions also was less than 1 ppmv. The estimated hazardous quotient (HQ) for the evaporator was 6.2e-6 as compared to 0.25 for the EPA target criteria. The cancer risk was 1.3e-10 compared to an EPA target of le-5.

  16. NWCF Evaporator Tank System 2001 Offgas Emissions Inventory

    SciTech Connect

    Boardman, Richard Doin; Lamb, Kenneth Mitchel; Matejka, Leon Anthony; Nenni, Joseph A

    2002-02-01

    An offgas emissions inventory and liquid stream characterization of the Idaho New Waste Calcining Facility (NWCF) Evaporator Tank System (ETS), formerly known as the High Level Liquid Waste Evaporator (HLLWE), has been completed. The emissions rates of volatile and semi-volatile organic compounds, multiple metals, particulate, and hydrochloric acid were measured in accordance with an approved Quality Assurance Project Plan (QAPjP) and Test Plan that invoked U.S. Environmental Protection Agency (EPA) standard sample collection and analysis procedures. Offgas samples were collected during the start up and at the end of evaporator batches when it was hypothesized the emissions would be at peak rates. Corresponding collection of samples from the evaporator feed overhead condensate, and bottoms was made at approximately the same time as the emissions inventory to support material balance determinations for the evaporator process. The data indicate that organic compound emissions are slightly higher at the beginning of the batch while metals emissions, including mercury, are slightly higher at the end of the evaporator batch. The maximum emissions concentrations are low for all constituents of primary concern. Mercury emissions were less than 5 ppbv, while the sum of HCl and Cl2 emissions was less than 1 ppmv. The sum of all organic emissions also was less than 1 ppmv. The estimated hazardous quotient (HQ) for the evaporator was 6.2e-6 as compared to 0.25 for the EPA target criteria. The cancer risk was 1.3e-10 compared to an EPA target of le-5.

  17. Particle deposition on superhydrophobic surfaces by sessile droplet evaporation

    NASA Astrophysics Data System (ADS)

    Dicuangco, Mercy Grace

    Prediction and active control of the spatial distribution of particulate deposits obtained from sessile droplet evaporation is essential in ink-jet printing, nanostructure assembly, biotechnology, and other applications that require localized deposits. In recent years, sessile droplet evaporation on bio-inspired superhydrophobic surfaces has become an attractive method for depositing materials on a site-specific, localized region, but is less explored compared to evaporative deposition on hydrophilic surfaces. It is therefore of interest to understand particle deposition during droplet evaporation on superhydrophobic surfaces to enable accurate prediction and tunable control of localized deposits on such surfaces. The purpose of the present work is to explore the morphology of particles deposited on superhydrophobic surfaces by the evaporation of sessile water droplets containing suspended latex spheres. Droplet evaporation experiments are performed on non-wetting, textured surfaces with varying geometric parameters. The temporal evolution of the droplet contact radius and contact angle throughout the evaporation process are tracked by visualizing the transient droplet shape and wetting behavior. The droplets are observed to exhibit a combination of the following modes of evaporation: the constant contact radius mode, the constant contact angle mode, and the mixed mode in which the contact angle and the contact radius change simultaneously. After complete dry-out, the remaining particulate deposits are qualitatively and quantitatively characterized to describe their spatial distribution. In the first part of the study, the test surfaces are maintained at different temperatures. Experiments are conducted at ambient conditions and at elevated substrate temperatures of approximately 40°C, 50°C, and 60°C. The results show that droplet evaporation on superhydrophobic surfaces, driven by either mass diffusion at ambient conditions or by substrate heating, suppresses

  18. The Effect of Dynamic Evaporation Rates on the Mobility of Pharmaceuticals in Unsaturated Environments

    NASA Astrophysics Data System (ADS)

    Normile, H.; Papelis, C.; Kibbey, T. C. G.

    2015-12-01

    The focus of this work was on investigating how dynamic rates of evaporation affect the fate and transport of pharmaceutical compounds in unsaturated porous media. The environmental processes of saturation and evaporation control local concentrations of contaminants in pore water of porous media. Specifically, the rate of evaporation can affect the identity and extent of solid formation of a pharmaceutical compound. A range of experiments with different evaporation rates were conducted on sand columns saturated with a solution of ciprofloxacin, a fluoroquinolone antibiotic. Experiments were designed to simulate increased and decreased pore-water concentrations of a compound due to evaporation and resaturation, respectively. Results suggest that varied rates of evaporation cause differences in compound adsorption behavior. This result has significant implications for understanding fate and transport within the unsaturated zone. Preliminary models exploring the impact on contaminant mobility are discussed.

  19. The lifetime of evaporating dense sprays

    NASA Astrophysics Data System (ADS)

    de Rivas, Alois; Villermaux, Emmanuel

    2015-11-01

    We study the processes by which a set of nearby liquid droplets (a spray) evaporates in a gas phase whose relative humidity (vapor concentration) is controlled at will. A dense spray of micron-sized water droplets is formed in air by a pneumatic atomizer and conveyed through a nozzle in a closed chamber whose vapor concentration has been pre-set to a controlled value. The resulting plume extension depends on the relative humidity of the diluting medium. When the spray plume is straight and laminar, droplets evaporate at its edge where the vapor is saturated, and diffuses through a boundary layer developing around the plume. We quantify the shape and length of the plume as a function of the injecting, vapor diffusion, thermodynamic and environment parameters. For higher injection Reynolds numbers, standard shear instabilities distort the plume into stretched lamellae, thus enhancing the diffusion of vapor from their boundary towards the diluting medium. These lamellae vanish in a finite time depending on the intensity of the stretching, and relative humidity of the environment, with a lifetime diverging close to the equilibrium limit, when the plume develops in an medium saturated in vapor. The dependences are described quantitatively.

  20. Thermodynamic Modeling of the SRS Evaporators: Part II. The 3H System

    SciTech Connect

    Jantzen, C.M.

    2001-10-02

    Accumulations of two solid phases have formed scale deposits in the Savannah River Site 2H Evaporator system since late 1996. The aluminosilicate scale deposits caused the evaporator pot to become inoperable in October 1999. Accumulations of the diuranate phase have caused criticality concerns in the SRS 2H Evaporator. In order to ensure that similar deposits are not and will not form in the SRS 3H Evaporator, thermodynamically derived activity diagrams specific to the feeds processed from Tanks 30 and 32 are evaluated in this report.

  1. A theoretical study of the spheroidal droplet evaporation in forced convection

    NASA Astrophysics Data System (ADS)

    Li, Jie; Zhang, Jian

    2014-11-01

    In many applications, the shape of a droplet may be assumed to be an oblate spheroid. A theoretical study is conducted on the evaporation of an oblate spheroidal droplet under forced convection conditions. Closed-form analytical expressions of the mass evaporation rate for an oblate spheroid are derived, in the regime of controlled mass-transfer and heat-transfer, respectively. The variation of droplet size during the evaporation process is presented in the regime of shrinking dynamic model. Comparing with the droplets having the same surface area, an increase in the aspect ratio enhances the mass evaporation rate and prolongs the burnout time.

  2. Theoretical investigation of the injection and evaporation of water in a hydrogen/oxygen steam generator

    NASA Astrophysics Data System (ADS)

    Beer, Stefan

    1991-07-01

    Water is injected into the gas stream for the purpose of cooling the reaction products resulting from the stochiometric combustion of hydrogen with oxygen. The penetration of the jet decisively influences the temperature profile across the flow cross section in the water vapor. The penetration of the water jet into the stream is calculated using the jet shedding model and compared with the garden hose model. Models for the evaporation of water droplets in superheated steam are developed for calculating the evaporation paths. The parameters which influence the injection and evaporation process are subjected to variation and their effects in the evaporation paths are analyzed.

  3. Rare Earth Element Fractionation During Evaporation of Chondritic Material

    NASA Astrophysics Data System (ADS)

    Wang, J.; Davis, A. M.; Clayton, R. N.

    1993-07-01

    -rich inclusions, which have large negative Ce and small negative Pr anomalies [7], probably formed by extremely rapid evaporation in the solar nebula or by evaporation in an environment much poorer in hydrogen. Normal CAIs do not have Ce anomalies. If they experienced evaporation in the solar nebula, the process must have occurred slowly enough to maintain reducing conditions in the residue. References: [1] Davis A. M. et al. (1990) Nature, 347, 655-658. [2] Boynton W. V. (1975) GCA, 39, 569-584. [3] Davis A. M. and Grossman L. (1979) GCA, 43, 1611-1632. [4] Hashimoto A. (1990) Nature, 347, 53-55. [5] Hashimoto A. (1983) Geochem. J., 17, 111-145. [6] Davis A. M. et al. (1982) GCA, 46, 1627-1651. [7] Ireland T. R. et al. (1992) GCA, 56, 2503-2520. Figure 1, which appears in the hard copy, shows fraction remaining vs. percent evaporated for vacuum evaporation of material of chondritic composition.

  4. Simultaneous Evaporation of Cu and Sn from Liquid Steel

    NASA Astrophysics Data System (ADS)

    Jung, Sung-Hoon; Kang, Youn-Bae

    2016-05-01

    In order to understand evaporation refining of tramp elements in molten ferrous scrap, Cu and Sn, a series of experiments were carried out using liquid-gas reaction in a levitation melting equipment. Effect of S and C, which are abundant in hot metal from ironmaking process, was examined and analyzed by employing a comprehensive evaporation kinetic model developed by the present authors (Jung et al. in Metall Mater Trans B 46B:250-258, 2014; Jung et al. in Metall Mater Trans B 46B:259-266, 2014; Jung et al. in Metall Mater Trans B 46B:267-277, 2014; Jung and Kang in Metall Mater Trans B 10.1007/s11663-016-0601-5, 2016). Evaporation of Cu and Sn were treated by evaporation of individual species such as Cu(g), CuS(g), Sn(g), and SnS(g), along with CS2(g). Decrease of Cu and Sn content in liquid steel was in good agreement with the model prediction. Optimum conditions of steel composition for the rapid evaporation of Cu and Sn were proposed by utilizing the model predictions.

  5. Simultaneous Evaporation of Cu and Sn from Liquid Steel

    NASA Astrophysics Data System (ADS)

    Jung, Sung-Hoon; Kang, Youn-Bae

    2016-08-01

    In order to understand evaporation refining of tramp elements in molten ferrous scrap, Cu and Sn, a series of experiments were carried out using liquid-gas reaction in a levitation melting equipment. Effect of S and C, which are abundant in hot metal from ironmaking process, was examined and analyzed by employing a comprehensive evaporation kinetic model developed by the present authors (Jung et al. in Metall Mater Trans B 46B:250-258, 2014; Jung et al. in Metall Mater Trans B 46B:259-266, 2014; Jung et al. in Metall Mater Trans B 46B:267-277, 2014; Jung and Kang in Metall Mater Trans B 10.1007/s11663-016-0601-5, 2016). Evaporation of Cu and Sn were treated by evaporation of individual species such as Cu(g), CuS(g), Sn(g), and SnS(g), along with CS2(g). Decrease of Cu and Sn content in liquid steel was in good agreement with the model prediction. Optimum conditions of steel composition for the rapid evaporation of Cu and Sn were proposed by utilizing the model predictions.

  6. Numerical Study of a Hydrodynamic Instability Driven by Evaporation

    NASA Astrophysics Data System (ADS)

    Hernandez-Zapata, Sergio; Romo-Cruz, Julio Cesar Ruben; Lopez-Sanchez, Erick Javier; Ruiz-Chavarria, Gerardo

    2013-11-01

    The study of hydrodynamic instabilities in liquid layers produced by evaporation has several applications on industry and technology. In this work we study numerically the conditions under which a liquid layer becomes unstable when evaporation in the vapor-liquid interphase is present. The evaporation process follows the Hertz-Knudsen law (the evaporation rate is proportional to the difference between the saturated vapor pressure at the liquid layer temperature and the vapor partial pressure in the environment). Additionally to the usual boundary conditions on solid walls (for example, the non-slip condition for the velocity), we analyze the boundary conditions in the vapor-liquid interphase where the momentum and energy balances have to be taken into account and where the evaporation plays a crucial role. To solve this problem the linear theory of stability is used; that is, a small perturbation around the basic solution is applied (flow at rest and a temperature stationary field). The equations are solved using the Chebyshev pseudo-spectral method. The results are compared with the more usual Rayleigh-Bénard and Marangoni mechanisms as well as with some experiments carried out by our team. Authors acknowledge DGAPA-UNAM by support under project IN116312, ``Vorticidad y Ondas no lineales en fluidos.''

  7. Simulations of diffusive lithium evaporation onto the NSTX vessel walls

    SciTech Connect

    Stotler, D.; Krstic, Predrag S; Skinner, C. H.; Blanchard, W.; Kugel, H.; Schneider, H; Zakharov, L. E.

    2011-01-01

    A model for simulating the diffusive evaporation of lithium into a helium filled NSTX vacuum vessel is described and validated against an initial set of deposition experiments. The DEGAS 2 based model consists of a three-dimensional representation of the vacuum vessel, the elastic scattering process, and a kinetic description of the evaporated atoms. Additional assumptions are required to account for deuterium out-gassing during the validation experiments. The model agrees with the data over a range of pressures to within the estimated uncertainties. Suggestions are made for more discriminating experiments that will lead to an improved model.

  8. Kinetics of the evaporative cooling of an atomic beam

    SciTech Connect

    Lahaye, Thierry; Guery-Odelin, David

    2006-06-15

    We compare two distinct models of evaporative cooling of a magnetically guided atomic beam: a continuous one, consisting in approximating the atomic distribution function by a truncated equilibrium distribution, and a discrete-step one, in which the evaporation process is described in terms of successive steps consisting in a truncation of the distribution followed by rethermalization. Calculations are performed for the semilinear potential relevant for experiments. We show that it is possible to map one model onto the other, allowing us to infer, for the discrete-step model, the rethermalization kinetics, which turns out to be strongly dependent upon the shape of the confining potential.

  9. Dewetting of evaporating thin films over nanometer-scale topographies

    NASA Astrophysics Data System (ADS)

    Akbarzadeh, A. M.; Moosavi, A.; Moghimi Kheirabadi, A.

    2014-07-01

    A lubrication model is used to study dewetting of an evaporating thin film layer over a solid substrate with a nanometer-scale topography. The effects of the geometry of the topography, the contact angle, the film thickness, and the slippage on the dewetting have been studied. Our results reveal that the evaporation enhances the dewetting process and reduces the depinning time over the topography. Also it is shown that the depinning time is inversely proportional to the slippage and increasing the contact angle may considerably reduce the depinning time, while the film thickness increases the depinning time.

  10. Simulation of Diffusive Lithium Evaporation Onto the NSTX Vessel Walls

    SciTech Connect

    Stotler, D. P.; Skinner, C. H.; Blanchard, W. R.; Krstic, P. S.; Kugel, H. W.; Schneider, H.; Zakharov, L. E.

    2010-12-09

    A model for simulating the diffusive evaporation of lithium into a helium filled NSTX vacuum vessel is described and validated against an initial set of deposition experiments. The DEGAS 2 based model consists of a three-dimensional representation of the vacuum vessel, the elastic scattering process, and a kinetic description of the evaporated atoms. Additional assumptions are required to account for deuterium out-gassing during the validation experiments. The model agrees with the data over a range of pressures to within the estimated uncertainties. Suggestions are made for more discriminating experiments that will lead to an improved model.

  11. Evaporation and condensation at a liquid surface. II. Methanol

    NASA Astrophysics Data System (ADS)

    Matsumoto, Mitsuhiro; Yasuoka, Kenji; Kataoka, Yosuke

    1994-11-01

    The rates of evaporation and condensation of methanol under the vapor-liquid equilibrium condition at the temperature of 300 and 350 K are investigated with a molecular dynamics computer simulation. Compared with the argon system (reported in part I), the ratio of self-reflection is similar (˜10%), but the ratio of molecule exchange is several times larger than the argon, which suggests that the conventional assumption of condensation as a unimolecular process completely fails for associating fluids. The resulting total condensation coefficient is 20%-25%, and has a quantitative agreement with a recent experiment. The temperature dependence of the evaporation-condensation behavior is not significant.

  12. Evaporation of iodine-containing off-gas scrubber solution

    DOEpatents

    Partridge, J.A.; Bosuego, G.P.

    1980-07-14

    Mercuric nitrate-nitric acid scrub solutions containing radioiodine may be reduced in volume without excessive loss of volatile iodine. The use of concentrated nitric acid during an evaporation process oxidizes the mercury-iodide complex to a less volatile mercuric iodate precipitate.

  13. Experiments and Modeling of Evaporating/Condensing Menisci

    NASA Technical Reports Server (NTRS)

    Plawsky, Joel; Wayner, Peter C., Jr.

    2013-01-01

    Discuss the Constrained Vapor Bubble (CVB) experiment and how it aims to achieve a better understanding of the physics of evaporation and condensation and how they affect cooling processes in microgravity using a remotely controlled microscope and a small cooling device.

  14. Black hole evaporation in a noncommutative charged Vaidya model

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Javed, W.

    2012-06-01

    We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordström-like solution of this model, which leads to an exact ( t - r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.

  15. Evaporation-driven clustering of microscale pillars and lamellae

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Hong; Kim, Jungchul; Kim, Ho-Young

    2016-02-01

    As a liquid film covering an array of micro- or nanoscale pillars or lamellae evaporates, its meniscus pulls the elastic patterns together because of capillary effects, leading to clustering of the slender microstructures. While this elastocapillary coalescence may imply various useful applications, it is detrimental to a semiconductor manufacturing process called the spin drying, where a liquid film rinses patterned wafers until drying. To understand the transient mechanism underlying such self-organization during and after liquid evaporation, we visualize the clustering dynamics of polymer micropatterns. Our visualization experiments reveal that the patterns clumped during liquid evaporation can be re-separated when completely dried in some cases. This restoration behavior is explained by considering adhesion energy of the patterns as well as capillary forces, which leads to a regime map to predict whether permanent stiction would occur. This work does not only extend our understanding of micropattern stiction, but also suggests a novel path to control and prevent pattern clustering.

  16. Black hole evaporation in a noncommutative charged Vaidya model

    SciTech Connect

    Sharif, M. Javed, W.

    2012-06-15

    We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordstroem-like solution of this model, which leads to an exact (t - r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.

  17. Electron beam lithography on irregular surfaces using an evaporated resist.

    PubMed

    Zhang, Jian; Con, Celal; Cui, Bo

    2014-04-22

    An electron beam resist is typically applied by spin-coating, which cannot be reliably applied on nonplanar, irregular, or fragile substrates. Here we demonstrate that the popular negative electron beam resist polystyrene can be coated by thermal evaporation. A high resolution of 30 nm half-pitch was achieved using the evaporated resist. As a proof of concept of patterning on irregular surfaces, we fabricated nanostructures on the AFM cantilever and the optical fiber. Although an ice (H2O) resist has also been recently demonstrated as being capable of nanopatterning on irregular and fragile substrates, it requires specially designed accessories mounted inside a SEM chamber, whereas our process works with any thermal evaporator and is thus simpler and much more accessible. Nanofabrication on nonplanar surfaces may find applications in fields such as (AFM) tip-enhanced Raman spectroscopy for chemical analysis and lab-on-fiber technology. PMID:24669781

  18. Evaporation model for beam based additive manufacturing using free surface lattice Boltzmann methods

    NASA Astrophysics Data System (ADS)

    Klassen, Alexander; Scharowsky, Thorsten; Körner, Carolin

    2014-07-01

    Evaporation plays an important role in many technical applications including beam-based additive manufacturing processes, such as selective electron beam or selective laser melting (SEBM/SLM). In this paper, we describe an evaporation model which we employ within the framework of a two-dimensional free surface lattice Boltzmann method. With this method, we solve the hydrodynamics as well as thermodynamics of the molten material taking into account the mass and energy losses due to evaporation and the recoil pressure acting on the melt pool. Validation of the numerical model is performed by measuring maximum melt depths and evaporative losses in samples of pure titanium and Ti-6Al-4V molten by an electron beam. Finally, the model is applied to create processing maps for an SEBM process. The results predict that the penetration depth of the electron beam, which is a function of the acceleration voltage, has a significant influence on evaporation effects.

  19. Modeling of two-layer liquid-gas flow with account for evaporation

    NASA Astrophysics Data System (ADS)

    Goncharova, O. N.; Rezanova, E. V.; Lyulin, Yu. V.; Kabov, O. A.

    2015-09-01

    Two-layer gas-liquid flows and evaporation intensity at the interface were studied. The influence of gas flow rate, longitudinal gradient of temperature, the Soret effect on the nature of flow and transfer processes was demonstrated. Experimental and theoretical results were compared; they show dependence of evaporation at the interface on gas flow rates.

  20. Alternative Methods for the Reduction of Evaporation: Practical Exercises for the Science Classroom

    ERIC Educational Resources Information Center

    Schouten, Peter; Putland, Sam; Lemckert, Charles J.; Parisi, Alfio V.; Downs, Nathan

    2012-01-01

    Across the world, freshwater is valued as the most critically important natural resource, as it is required to sustain the cycle of life. Evaporation is one of the primary environmental processes that can reduce the amount of quality water available for use in industrial, agricultural and household applications. The effect of evaporation becomes…

  1. Influence of Spray Formulation and Leaf Surface Structure on Droplet Evaporation and Wetted Area

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fate of pesticide droplets on leaves is seriously influenced by spray formulations and fine structures on leaf surfaces. Evaporation times and wetted areas of droplets on hairy and waxy geranium leaf surfaces were determined under controlled conditions. Droplet evaporation processes were taken w...

  2. ON THE THEORY RELATING CHANGES IN AREA-AVERAGE AND PAN EVAPORATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Theory relating changes in the area-average evaporation from a landscape with changes in the evaporation from pans or open water within the landscape is developed. Such changes can arise in two ways, by Type (a) processes related to large-scale changes in atmospheric concentrations and circulation t...

  3. Soil-water evaporation dynamics determined with measurement of sensible heat transfer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil-water evaporation is important in both the hydrologic cycle and the surface energy balance. Yet, routine measurements are unable to capture rapidly shifting near-surface soil heat and water processes involved in evaporation. Recent improvements for fine-scale measurement of soil thermal propert...

  4. Combination of imipenem and TAK-242, a Toll-like receptor 4 signal transduction inhibitor, improves survival in a murine model of polymicrobial sepsis.

    PubMed

    Sha, Takuryu; Iizawa, Yuji; Ii, Masayuki

    2011-02-01

    Sepsis is characterized by an excessive host response to infection. Toll-like receptors (TLRs) are essential for triggering this type of host immune response. Toll-like receptor 4 mediates recognition of LPS from gram-negative bacteria and is an important initiator of sepsis. In the present study, we evaluated the efficacy of TAK-242, a novel TLR4 signal transduction inhibitor, in a murine cecal ligation and puncture (CLP) model. Treatment with TAK-242 (10 mg/kg i.v.) in combination with imipenem (1 mg/kg s.c.) 1 h after CLP significantly increased the survival rates of mice from 17% to 50% (P ≤ 0.01) and suppressed CLP-induced increases in serum levels of IL-1[beta], IL-6, IL-10, and macrophage inflammatory protein 2 by 64%, 73%, 79%, and 81%, respectively (P ≤ 0.025). Additionally, coadministration of TAK-242 with imipenem after CLP significantly inhibited CLP-induced decreases in blood platelet counts by 37% (P ≤ 0.025) and increases in serum levels of alanine aminotransferase by 32% (P ≤ 0.025) and blood urea nitrogen by 43% (P ≤ 0.025). TAK-242 at a dose of 10 mg/kg had no effect on bacterial counts in blood, suggesting that it does not affect blood bacteria spread. These results indicate that TAK-242 shows therapeutic effects in murine polymicrobial sepsis, and it may be a potential therapeutic agent for the treatment of sepsis. PMID:20720515

  5. AZ 242, a novel PPARalpha/gamma agonist with beneficial effects on insulin resistance and carbohydrate and lipid metabolism in ob/ob mice and obese Zucker rats.

    PubMed

    Ljung, Bengt; Bamberg, Krister; Dahllöf, Björn; Kjellstedt, Ann; Oakes, Nicholas D; Ostling, Jörgen; Svensson, Lennart; Camejo, Germán

    2002-11-01

    Abnormalities in fatty acid (FA) metabolism underlie the development of insulin resistance and alterations in glucose metabolism, features characteristic of the metabolic syndrome and type 2 diabetes that can result in an increased risk of cardiovascular disease. We present pharmacodynamic effects of AZ 242, a novel peroxisome proliferator activated receptor (PPAR)alpha/gamma agonist. AZ 242 dose-dependently reduced the hypertriglyceridemia, hyperinsulinemia, and hyperglycemia of ob/ob diabetic mice. Euglycemic hyperinsulinemic clamp studies showed that treatment with AZ 242 (1 micromol/kg/d) restored insulin sensitivity of obese Zucker rats and decreased insulin secretion. In vitro, in reporter gene assays, AZ 242 activated human PPARalpha and PPARgamma with EC(50) in the micro molar range. It also induced differentiation in 3T3-L1 cells, an established PPARgamma effect, and caused up-regulation of liver fatty acid binding protein in HepG-2 cells, a PPARalpha-mediated effect. PPARalpha-mediated effects of AZ 242 in vivo were documented by induction of hepatic cytochrome P 450-4A in mice. The results indicate that the dual PPARalpha/gamma agonism of AZ 242 reduces insulin resistance and has beneficial effects on FA and glucose metabolism. This effect profile could provide a suitable therapeutic approach to the treatment of type 2 diabetes, metabolic syndrome, and associated vascular risk factors. PMID:12401884

  6. Out-of-tank evaporator demonstration. Final report

    SciTech Connect

    Lucero, A.J.; Jennings, H.L.; VanEssen, D.C.

    1998-02-01

    The project reported here was conducted to demonstrate a skid-mounted, subatmospheric evaporator to concentrate liquid low-level waste (LLLW) stored in underground tanks at Oak Ridge National Laboratory (ORNL). This waste is similar to wastes stored at Hanford and Savannah River. A single-stage subatmospheric evaporator rated to produce 90 gallons of distillate per hour was procured from Delta Thermal, Inc., of Pensacola, Florida, and installed in an existing building. During the 8-day demonstration, 22,000 gal of LLLW was concentrated by 25% with the evaporator system. Decontamination factors achieved averaged 5 x 10{sup 6} (i.e., the distillate contained five million times less Cesium 137 than the feed). Evaporator performance substantially exceeded design requirements and expectations based on bench-scale surrogate test data. Out-of tank evaporator demonstration operations successfully addressed the feasibility of hands-on maintenance. Demonstration activities indicate that: (1) skid-mounted, mobile equipment is a viable alternative for the treatment of ORNL LLLW, and (2) hands-on maintenance and decontamination for movement to another site is achievable. Cost analysis show that 10% of the demonstration costs will be immediately recovered by elimination of solidification and disposal costs. The entire cost of the demonstration can be recovered by processing the inventory of Melton Valley Storage Tank waste and/or sluice water prior to solidifications. An additional savings of approximately $200,000 per year can be obtained by processing newly generated waste through the system. The results indicate that this type of evaporator system should be considered for application across the DOE complex. 25 refs., 11 figs., 2 tabs.

  7. Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

    SciTech Connect

    Adamson, Duane J.; Nash, Charles A.; McCabe, Daniel J.; Crawford, Charles L.; Wilmarth, William R.

    2014-01-27

    The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream, LAW Off-Gas Condensate, from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of canistered glass waste forms. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to be within acceptable concentration ranges in the LAW glass. Diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the impact of potential future disposition of this stream in the Hanford tank farms, and investigates auxiliary evaporation to enable another disposition path. Unless an auxiliary evaporator is used, returning the stream to the tank farms would require evaporation in the 242-A evaporator. This stream is expected to be unusual because it will be very high in corrosive species that are volatile in the melter

  8. A comparison of continental actual evaporation estimates for Africa to improve hydrological drought forecasting

    NASA Astrophysics Data System (ADS)

    Trambauer, Patricia; Maskey, Shreedhar; Werner, Micha

    2013-04-01

    Evaporation is a key process in the development of hydrological and agricultural droughts. Although distributed drought indicators are often calculated using estimates of evaporation or soil moisture, the estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flows. On the other hand, other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products; the evaporation results from the HTESSEL model and ERA-Interim (both based on the energy balance approach), both the MOD16 evaporation product (largely derived from MODIS remote sensing images), and the GLEAM product (derived from satellite observations). Three alternative versions of the PCR-GLOBWB hydrological model were also considered. In the first the model structure was amended by introducing an irrigation scheme, while in the second and third forcing data (precipitation and potential evaporation) were modified to assess the impact that the choice of forcing has on the actual evaporation fluxes simulated by the model. This resulted in eight products of actual evaporation, and derived drought indices were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and using statistical methods. The comparison indicated that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5

  9. Sensitivity of potential evaporation estimates to 100 years of climate variability

    NASA Astrophysics Data System (ADS)

    Bartholomeus, Ruud; Stagge, James; Tallaksen, Lena; Witte, Jan-Philip

    2015-04-01

    Evaporation from the vegetated surface is the largest loss term in many, if not the most, water balance studies on earth. As a consequence, an accurate representation of evaporation fluxes is required for appropriate quantification of surface runoff, the soil moisture budget, transpiration, recharge and groundwater processes. However, despite being a key component of the water balance, evaporation figures are usually associated with large uncertainties, as this term is difficult to measure or estimate by modeling. Many modeling frameworks have used the concept of potential evaporation, often estimated for different vegetation classes by multiplying the evaporation from a reference surface ('reference evaporation') with crop specific scaling factors ('crop factors'). Though this two-step potential evaporation approach undoubtedly has practical advantages, the empirical nature of both reference evaporation methods and crop factors limits its usability in extrapolations under non-stationary climatic conditions. We quantified the sensitivity of potential evaporation estimates for different vegetation classes using the two-step approach when calibrated using a non-stationary climate. We used the past century's time series of observed climate, containing non-stationary signals of multi-decadal atmospheric oscillations, global warming, and global dimming/brightening, to evaluate the sensitivity of potential evaporation estimates to the choice and length of the calibration period. We show that using empirical coefficients outside their calibration range may lead to systematic differences between process-based and empirical reference evaporation methods, and systematic errors in estimated potential evaporation components. Our hydrological models are to varying extent regression models, which limits their general applicability, and the estimation of potential evaporation is closely linked to climate variability. With our analysis, we want to raise awareness and to provide a

  10. Evaporative cooling of speleothem drip water.

    PubMed

    Cuthbert, M O; Rau, G C; Andersen, M S; Roshan, H; Rutlidge, H; Marjo, C E; Markowska, M; Jex, C N; Graham, P W; Mariethoz, G; Acworth, R I; Baker, A

    2014-01-01

    This study describes the first use of concurrent high-precision temperature and drip rate monitoring to explore what controls the temperature of speleothem forming drip water. Two contrasting sites, one with fast transient and one with slow constant dripping, in a temperate semi-arid location (Wellington, NSW, Australia), exhibit drip water temperatures which deviate significantly from the cave air temperature. We confirm the hypothesis that evaporative cooling is the dominant, but so far unattributed, control causing significant disequilibrium between drip water and host rock/air temperatures. The amount of cooling is dependent on the drip rate, relative humidity and ventilation. Our results have implications for the interpretation of temperature-sensitive, speleothem climate proxies such as δ(18)O, cave microecology and the use of heat as a tracer in karst. Understanding the processes controlling the temperature of speleothem-forming cave drip waters is vital for assessing the reliability of such deposits as archives of climate change. PMID:24895139

  11. Evaporative cooling of speleothem drip water

    PubMed Central

    Cuthbert, M. O.; Rau, G. C.; Andersen, M. S.; Roshan, H.; Rutlidge, H.; Marjo, C. E.; Markowska, M.; Jex, C. N.; Graham, P. W.; Mariethoz, G.; Acworth, R. I.; Baker, A.

    2014-01-01

    This study describes the first use of concurrent high-precision temperature and drip rate monitoring to explore what controls the temperature of speleothem forming drip water. Two contrasting sites, one with fast transient and one with slow constant dripping, in a temperate semi-arid location (Wellington, NSW, Australia), exhibit drip water temperatures which deviate significantly from the cave air temperature. We confirm the hypothesis that evaporative cooling is the dominant, but so far unattributed, control causing significant disequilibrium between drip water and host rock/air temperatures. The amount of cooling is dependent on the drip rate, relative humidity and ventilation. Our results have implications for the interpretation of temperature-sensitive, speleothem climate proxies such as δ18O, cave microecology and the use of heat as a tracer in karst. Understanding the processes controlling the temperature of speleothem-forming cave drip waters is vital for assessing the reliability of such deposits as archives of climate change. PMID:24895139

  12. Observations on an evaporative, elbow thermosyphon

    SciTech Connect

    Lock, G.S.H.; Fu, J. )

    1993-05-01

    The performance of the evaporative elbow system was found to be superior to that of the nonevaporative system, but comparable to the performance of the linear system. The parametric role of the evaporator wall temperature, the condenser wall temperature, and the vapor saturation temperature was demonstrated, each revealing a similar monotonic effect. With the evaporator upright, the data were found to be similar to, but displaced from, the upright condenser data. The upright evaporator gave the better performance, but not overwhelmingly so. The limit of performance with the condenser upright was found to be dictated by evaporator dryout. In the upright evaporator configuration, the limit may be attributed to flooding in the poorly draining condenser; this limit was indistinguishable from geyser behavior at low vapor pressures. 16 refs., 3 figs.

  13. Energy savings from indirect evaporative pre-cooling: Control strategies and commissioning

    SciTech Connect

    Felts, D.; Jump, D.A.

    1998-07-01

    Package rooftop air conditioning units (RTU) with evaporative pre-cooling systems were installed at an Agricultural History Museum and conference center in the northern Sacramento Valley in California, a hot and dry summer climate region. The evaporative pre-coolers serve to extend the economizer range of the RTU's. A commissioning team monitored the performance of the RTU evaporative pre-coolers. The purpose of the monitoring was to determine if changes were warranted to optimize the system's energy efficiency. The commissioning process revealed that the RTU evaporative pre-coolers were being controlled by the economizer control cycle. With this control cycle, the evaporative pre-cooler operates when the outdoor air temperature is falling below the space return air temperature. This means that the pre-cooler will never operate at peak load conditions. The conference center is an assembly occupancy. Building codes require significant levels of outdoor air for ventilation. The evaporative pre-cooler system provides the means to significantly offset the energy requirements for cooling down and heating up this ventilation air. A DOE2 energy simulation analysis indicated that the evaporative pre-cooler could cut energy use by over 50% if it were working correctly. Investigation concludes that in buildings with high outdoor air requirements, evaporative pre-cooling, using building exhaust air as the indirect evaporative cooling source, significantly reduce building energy consumption. This evaporative pre-cooling technology works in any climate, regardless of outdoor conditions, since the return air stream exhausted from the building provides a relatively constant temperature and humidity source for evaporative cooling. An added benefit is that the evaporative pre-cooler heat exchanger recovers heat from the exhausted air stream in cold weather.

  14. Groundwater evaporation from salt pans: Examples from the eastern Arabian Peninsula

    NASA Astrophysics Data System (ADS)

    Schulz, Stephan; Horovitz, Marcel; Rausch, Randolf; Michelsen, Nils; Mallast, Ulf; Köhne, Maximilian; Siebert, Christian; Schüth, Christoph; Al-Saud, Mohammed; Merz, Ralf

    2015-12-01

    The major groundwater resources of the Arabian Peninsula are stored in the large sedimentary basins in its eastern part. Evaporation from continental salt pans (playas) is an important process in water resources assessments of its upper principal aquifers - the Upper Mega Aquifer system - as it constitutes a significant sink. However, literature values on evaporation rates vary widely and usually report about coastal salt pans where seawater evaporation is assumed. The present study applies different methods to provide a comprehensive picture of groundwater evaporation from salt pans of the Upper Mega Aquifer system. A remote sensing approach provided the spatial distribution and total salt pan area of about 36,500 km2. Hydrochemical and isotopic investigations revealed that from about 10% (3600 km2 ± 1600 km2) of the mapped salt pan area seawater evaporates. To estimate the groundwater evaporation rate from continental salt pans a laboratory column experiment was set up, implying a mean annual evaporation rate of about 42 mm ± 13 mm. In-situ analysis of water table fluctuations in the field suggested about 3 mm a-1 originate from recently infiltrated rainwater leading to an annual net groundwater evaporation of 39 mm ± 13 mm. Relating this number to the mapped salt pan area, from which groundwater evaporates, provides a total annual groundwater loss of 1.3 km3 ± 0.5 km3 for the Upper Mega Aquifer system.

  15. On the role of physiochemical properties on evaporation behavior of DISI biofuel sprays

    NASA Astrophysics Data System (ADS)

    Knorsch, Tobias; Heldmann, Markus; Zigan, Lars; Wensing, Michael; Leipertz, Alfred

    2013-06-01

    Biofuels and alternative fuels are increasingly being blended to conventional gasoline fuel to reduce the overall CO2 emissions. The effect on NOx and soot formation is still unclear as the atomization and evaporation of gasoline with biocomponents differ depending on fuel specific physiochemical properties. This work focuses on describing the biofuel evaporation behavior of gasoline sprays at homogeneous charge (early injection timing) and stratified-charge conditions (late injection timing mode) used in modern direct injection spark ignition engines (DISI). A spray plume of a 6-hole solenoid injector is analyzed in terms of liquid spray propagation, and local droplet sizes studied in an injection chamber. Depending on the operating conditions, different physiochemical properties are found to dominate the atomization and evaporation processes: For low and moderate ambient temperature and pressure, high-boiling point components show a strong influence on the spray droplet size distribution. However, at elevated temperature and pressure, the evaporation behavior changes completely. Due to a high degree of evaporation, the evaporation cooling effect dominates the local droplet sizes. Fuel mixtures owing a larger heat of vaporization show larger droplet sizes—even if these fuels have a lower boiling point. Depending on the local evaporation behavior, the different remaining droplet momentum in the spray controls the air entrainment and the subsequent progress of evaporation and mixing. Overall, it can be stated that the heat of vaporization is a dominating physiochemical property for the droplet evaporation rate at high-level supercharged conditions.

  16. Triple-line behavior and wettability controlled by nanocoated substrates: influence on sessile drop evaporation.

    PubMed

    Sobac, B; Brutin, D

    2011-12-20

    In this article, we investigate the influence of the surface properties of substrates on the evaporation process. Using various nanocoatings, it is possible to modify the surface properties of substrates, such as the roughness and the surface energy, while maintaining constant thermal properties. Experiments are conducted under atmospheric conditions with five fluids (methanol, ethanol, propanol, toluene and water) and four coatings (PFC, PTFE, SiOC, and SiO(x)). The various combinations of these fluids and coatings allow for a wide range of drop evaporation properties to be studied: the dynamics of the triple line, the volatility of fluids, and a large range of wettabilities (from 17 to 135°). The experimental data are in very good quantitative agreement with existing models of quasi-steady, diffusion-driven evaporation. The experimental results show that the dynamics of the evaporative rate are proportional to the dynamics of the wetting radius. Thus, the models succeed in describing the evaporative dynamics throughout the evaporation process regardless of the behavior of the triple line. Moreover, the use of various liquids reveals the validity of the models regardless of their volatility. The results also confirm the recent finding of a universal relation for the time evolution of the drop mass, independent of the drop size and initial contact angle. Finally, this study highlights the separate and coupled roles of the triple line and the wettability on the sessile drop evaporation process. Data reveal that the more wet and pinned a drop, the shorter the evaporation time. PMID:22054245

  17. The Mass-Dependence of Cadmium Isotope Fractionation During Evaporation

    NASA Astrophysics Data System (ADS)

    Rehkamper, M.; Wombacher, F.; Mezger, K.; Wiechert, U.

    2002-12-01

    Isotope fractionation laws relate the isotope fractionation factor αA of one isotope ratio to the fractionation factor αB of a second isotope ratio of the same element with a fractionation exponent β, such that αA = αBβ. In a recent paper, Young et al. (GCA 66, 1095-1104 (2002)) inferred that kinetic and equilibrium isotope fractionations are characterized by different mass functions, such that βkin is not equal to βeq. As a consequence, kinetic isotope fractionation is expected to produce fractionation lines in three isotope space that are different from those generated by equilibrium fractionation processes. Young et al. furthermore stated that the variability in mass-dependent fractionation laws may be sufficient to account for the negative Δ17O of tropospheric O2 and the Δ17O anomalies of minerals in SNC meteorites. Such variations have otherwise been interpreted as evidence of non-mass dependant isotope fractionations (Luz et al., Nature 400, 547-550 (1999); Farquhar et al., Science 280, 1589-1582 (1998)). In the present study, we investigated the mass-dependence of isotope fractionation by evaluating the results of evaporation experiments that produced very large differences in Cd isotope compositions (up to about 100‰ ). In these experiments, liquid Cd was evaporated into a vacuum at a temperature of about 200°C. The metal residues remaining after evaporation were analyzed for their Cd isotope composition by multiple-collector inductively coupled plasma-mass spectrometry (MC-ICPMS) relative to the unfractionated starting material. The precision of the measurements is sufficient to clearly distinguish between different fractionation mechanisms. In linearized three-isotope space, the residual Cd metals plot on fractionation lines (e.g., with a slope β = 2.049 +/- 2 for 106}Cd/{114Cd vs. 110}Cd/{114Cd) that are intermediate between the kinetic (β = 2.036) and the equilibrium (β = 2.075) fractionation lines. This can be explained by an

  18. Apparatus and method for evaporator defrosting

    DOEpatents

    Mei, Viung C.; Chen, Fang C.; Domitrovic, Ronald E.

    2001-01-01

    An apparatus and method for warm-liquid defrosting of the evaporator of a refrigeration system. The apparatus includes a first refrigerant expansion device that selectively expands refrigerant for cooling the evaporator, a second refrigerant expansion device that selectively expands the refrigerant after the refrigerant has passed through the evaporator, and a defrosting control for the first refrigerant expansion device and second refrigerant expansion device to selectively defrost the evaporator by causing warm refrigerant to flow through the evaporator. The apparatus is alternately embodied with a first refrigerant bypass and/or a second refrigerant bypass for selectively directing refrigerant to respectively bypass the first refrigerant expansion device and the second refrigerant expansion device, and with the defrosting control connected to the first refrigerant bypass and/or the second refrigerant bypass to selectively activate and deactivate the bypasses depending upon the current cycle of the refrigeration system. The apparatus alternately includes an accumulator for accumulating liquid and/or gaseous refrigerant that is then pumped either to a refrigerant receiver or the first refrigerant expansion device for enhanced evaporator defrosting capability. The inventive method of defrosting an evaporator in a refrigeration system includes the steps of compressing refrigerant in a compressor and cooling the refrigerant in the condenser such that the refrigerant is substantially in liquid form, passing the refrigerant substantially in liquid form through the evaporator, and expanding the refrigerant with a refrigerant expansion device after the refrigerant substantially passes through the evaporator.

  19. Evaporation of water droplets on "lock-and-key" structures with nanoscale features.

    PubMed

    Zhu, Xiaolong; Zhang, Chi; Liu, Xiaohan; Hansen, Ole; Xiao, Sanshui; Mortensen, N A; Zi, Jian

    2012-06-26

    Highly ordered poly(dimethylsiloxane) microbowl arrays (MBAs) and microcap arrays (MCAs) with "lock-and-key" properties are successfully fabricated by self-assembly and electrochemical deposition. The wetting properties and evaporation dynamics of water droplets for both cases have been investigated. For the MBAs case, the wetting radius of the droplets remains unchanged until the portion of the droplet completely dries out at the end of the evaporation process. The pinning state extends for more than 99.5% of the total evaporation time, and the pinning-shrinking transition is essentially prevented whereas in the case of the MCAs the contact radius exhibits distinct stages during evaporation and the contact line retreats significantly in the middle of the evaporation process. We explain the phenomenon by a qualitative energy balance argument based on the different shrinkage types of the nanoscale-folded contact line. PMID:22662879

  20. Evaporative cooling of potassium atoms

    NASA Astrophysics Data System (ADS)

    Inouye, Shin; Kishimoto, Tetsuo; Kobayashi, Jun; Aikawa, Kiyotaka; Noda, Kai; Arae, Takuto; Ueda, Masahito

    2007-06-01

    Recent advances in manipulating interactions between ultracold atoms opened up various new possibilities. One of the major goal of the field is to produce ultracold polar molecules. By utilizing a magnetic field induced Feshbach resonance, it is possible to produce heteronuclear molecules from a degenerate gas mixture. We are setting up an experiment to produce a degenerate gas mixture of fermionic alkali atoms, lithium-6 and potassium-40. Fermionic atoms are good candidate for minimizing the expected inelastic loss at the Feshbach resonance. For keeping the system as simple as possible, we decided to use bosonic potassium (potassium-41) as a coolant, and sympathetically cool the fermionic species. We will present our experimental setup and initial results for evaporatively cooling bosonic potassium atoms.

  1. Vacuum thermal evaporation of polyaniline doped with camphor sulfonic acid

    SciTech Connect

    Boyne, Devon; Menegazzo, Nicola; Pupillo, Rachel C.; Rosenthal, Joel; Booksh, Karl S.

    2015-05-15

    Intrinsically conducting polymers belong to a class of organic polymers with intriguing electronic and physical properties specifically for electro-optical applications. Significant interest into doped polyaniline (PAni) can be attributed to its high conductivity and environmental stability. Poor dissolution in most solvents has thus far hindered the successful integration of PAni into commercial applications, which in turn, has led to the investigations of various deposition and acidic doping methods. Physical vapor deposition methods, including D.C. magnetron sputtering and vacuum thermal evaporation, have shown exceptional control over physical film properties (thickness and morphology). However, resulting films are less conductive than films deposited by conventional methods (i.e., spin and drop casting) due to interruption of the hyperconjugation of polymer chains. Specifically, vacuum thermal evaporation requires a postdoping process, which results in incorporation of impurities and oxidation of surface moieties. In this contribution, thermally evaporated films, sequentially doped by vacuum evaporation of an organic acid (camphorsulfonic acid, CSA) is explored. Spectroscopic evidence confirms the successful doping of PAni with CSA while physical characterization (atomic force microscopy) suggests films retain good morphology and are not damaged by the doping process. The procedure presented herein also combines other postpreparation methods in an attempt to improve conductivity and/or substrate adhesion.

  2. Quantum evaporation of flavor-mixed particles

    NASA Astrophysics Data System (ADS)

    Medvedev, Mikhail V.

    2014-03-01

    Particles whose propagation (mass) and interaction (flavor) bases are misaligned are mixed, e.g., neutrinos, quarks, Kaons, etc. We show that interactions (elastic scattering) of individual mass-eigenstates can result in their inter-conversions. Most intriguing and counter-intuitive implication of this process is a new process, which we refer to as the ``quantum evaporation.'' Consider a mixed particle trapped in a gravitational potential. If such a particle scatters off something (e.g., from another mixed particle) elastically from time to time, this particle (or both particles, respectively) can eventually escape to infinity with no extra energy supplied. That is as if a ``flavor-mixed satellite'' hauled along a bumpy road puts itself in space without a rocket, fuel, etc. Of course, the process at hand is entirely quantum and has no counterpart in classical mechanics. It also has nothing to do with tunneling or other known processes. We discuss some implications to the dark matter physics, cosmology and cosmic neutrino background. Supported by grant DOE grant DE-FG02-07ER54940 and NSF grant AST-1209665.

  3. ACID EVAPORATION OF ULTIMA GOLD TM AB LIQUID SCINTILLATION COCKTAIL RESIDUE

    SciTech Connect

    Kyser, E.; Fondeur, F.; Crump, S.

    2011-12-21

    Prior analyses of samples from the F/H Lab solutions showed the presence of diisopropylnapthalene (DIN), a major component of Ultima Gold{trademark} AB liquid scintillation cocktail (LSC). These solutions are processed through H-Canyon Tank 10.5 and ultimately through the 17.8E evaporator. Similar solutions originated in SRNL streams sent to the same H Canyon tanks. This study examined whether the presence of these organics poses a process-significant hazard for the evaporator. Evaporation and calorimetry testing of surrogate samples containing 2000 ppm of Ultima Gold{trademark} AB LSC in 8 M nitric acid have been completed. These experiments showed that although reactions between nitric acid and the organic components do occur, they do not appear to pose a significant hazard for runaway reactions or generation of energetic compounds in canyon evaporators. The amount of off-gas generated was relatively modest and appeared to be well within the venting capacity of the H-Canyon evaporators. A significant fraction of the organic components likely survives the evaporation process primarily as non-volatile components that are not expected to represent any new process concerns during downstream operations such as neutralization. Laboratory Waste solutions containing minor amounts of DIN can be safely received, stored, transferred, and processed through the canyon waste evaporator.

  4. Waste characterization for radioactive liquid waste evaporators at Argonne National Laboratory - West.

    SciTech Connect

    Christensen, B. D.

    1999-02-15

    Several facilities at Argonne National Laboratory - West (ANL-W) generate many thousand gallons of radioactive liquid waste per year. These waste streams are sent to the AFL-W Radioactive Liquid Waste Treatment Facility (RLWTF) where they are processed through hot air evaporators. These evaporators remove the liquid portion of the waste and leave a relatively small volume of solids in a shielded container. The ANL-W sampling, characterization and tracking programs ensure that these solids ultimately meet the disposal requirements of a low-level radioactive waste landfill. One set of evaporators will process an average 25,000 gallons of radioactive liquid waste, provide shielding, and reduce it to a volume of six cubic meters (container volume) for disposal. Waste characterization of the shielded evaporators poses some challenges. The process of evaporating the liquid and reducing the volume of waste increases the concentrations of RCIU regulated metals and radionuclides in the final waste form. Also, once the liquid waste has been processed through the evaporators it is not possible to obtain sample material for characterization. The process for tracking and assessing the final radioactive waste concentrations is described in this paper, The structural components of the evaporator are an approved and integral part of the final waste stream and they are included in the final waste characterization.

  5. Nanofluid Drop Evaporation: Experiment, Theory, and Modeling

    NASA Astrophysics Data System (ADS)

    Gerken, William James

    Nanofluids, stable colloidal suspensions of nanoparticles in a base fluid, have potential applications in the heat transfer, combustion and propulsion, manufacturing, and medical fields. Experiments were conducted to determine the evaporation rate of room temperature, millimeter-sized pendant drops of ethanol laden with varying amounts (0-3% by weight) of 40-60 nm aluminum nanoparticles (nAl). Time-resolved high-resolution drop images were collected for the determination of early-time evaporation rate (D2/D 02 > 0.75), shown to exhibit D-square law behavior, and surface tension. Results show an asymptotic decrease in pendant drop evaporation rate with increasing nAl loading. The evaporation rate decreases by approximately 15% at around 1% to 3% nAl loading relative to the evaporation rate of pure ethanol. Surface tension was observed to be unaffected by nAl loading up to 3% by weight. A model was developed to describe the evaporation of the nanofluid pendant drops based on D-square law analysis for the gas domain and a description of the reduction in liquid fraction available for evaporation due to nanoparticle agglomerate packing near the evaporating drop surface. Model predictions are in relatively good agreement with experiment, within a few percent of measured nanofluid pendant drop evaporation rate. The evaporation of pinned nanofluid sessile drops was also considered via modeling. It was found that the same mechanism for nanofluid evaporation rate reduction used to explain pendant drops could be used for sessile drops. That mechanism is a reduction in evaporation rate due to a reduction in available ethanol for evaporation at the drop surface caused by the packing of nanoparticle agglomerates near the drop surface. Comparisons of the present modeling predictions with sessile drop evaporation rate measurements reported for nAl/ethanol nanofluids by Sefiane and Bennacer [11] are in fairly good agreement. Portions of this abstract previously appeared as: W. J

  6. Therapeutic effects of TAK-242, a novel selective Toll-like receptor 4 signal transduction inhibitor, in mouse endotoxin shock model.

    PubMed

    Sha, Takukyu; Sunamoto, Mie; Kitazaki, Tomoyuki; Sato, Jun; Ii, Masayuki; Iizawa, Yuji

    2007-10-01

    Ethyl (6R)-6-[N-(2-chloro-4-fluorophenyl)sulfamoyl]cyclohex-1-ene-1-carboxylate (TAK-242), a novel small molecule that selectively inhibits Toll-like receptor 4-mediated signaling, inhibits various kinds of inflammatory mediators such as nitric oxide (NO), tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6, IL-10, macrophage inhibitory protein (MIP)-2 and prostaglandin E2 from lipopolysaccharide (LPS)-stimulated macrophages. The effects of TAK-242 were evaluated in a mouse model of endotoxin shock. Intravenous administration of TAK-242 to mice 1 h before LPS challenge dose-dependently inhibited LPS-induced increases in serum levels of TNF-alpha, IL-1beta, IL-6, IL-10, MIP-2, and NO metabolites. TAK-242 protected mice from LPS-induced lethality in a similar dose-dependent manner, and rescued 100% of mice at a dose of 1 mg/kg. Interestingly, TAK-242 worked quickly, and showed beneficial effects even when administered after LPS challenge. Even though increases in serum levels of IL-6 and hypothermia were already evident 2 h after LPS challenge, TAK-242 administration inhibited further increase in IL-6 levels and decrease in body temperature. LPS-induced increases in serum levels of organ dysfunction markers, such as alanine aminotransferase, total bilirubin, and blood urea nitrogen, were also significantly suppressed by post-treatment as well as pre-treatment. Furthermore, administration of 3 mg/kg TAK-242 significantly increased survival of mice, even when given 4 h after LPS challenge. These results suggest that TAK-242 protects mice against LPS-induced lethality by inhibiting production of multiple cytokines and NO. TAK-242 has a quick onset of action and provides significant benefits by post-treatment, suggesting that it may be a promising drug candidate for the treatment of sepsis. PMID:17632100

  7. GLEAM v3: updated land evaporation and root-zone soil moisture datasets

    NASA Astrophysics Data System (ADS)

    Martens, Brecht; Miralles, Diego; Lievens, Hans; van der Schalie, Robin; de Jeu, Richard; Fernández-Prieto, Diego; Verhoest, Niko

    2016-04-01

    Evaporation determines the availability of surface water resources and the requirements for irrigation. In addition, through its impacts on the water, carbon and energy budgets, evaporation influences the occurrence of rainfall and the dynamics of air temperature. Therefore, reliable estimates of this flux at regional to global scales are of major importance for water management and meteorological forecasting of extreme events. However, the global-scale magnitude and variability of the flux, and the sensitivity of the underlying physical process to changes in environmental factors, are still poorly understood due to the limited global coverage of in situ measurements. Remote sensing techniques can help to overcome the lack of ground data. However, evaporation is not directly observable from satellite systems. As a result, recent efforts have focussed on combining the observable drivers of evaporation within process-based models. The Global Land Evaporation Amsterdam Model (GLEAM, www.gleam.eu) estimates terrestrial evaporation based on daily satellite observations of meteorological drivers of terrestrial evaporation, vegetation characteristics and soil moisture. Since the publication of the first version of the model in 2011, GLEAM has been widely applied for the study of trends in the water cycle, interactions between land and atmosphere and hydrometeorological extreme events. A third version of the GLEAM global datasets will be available from the beginning of 2016 and will be distributed using www.gleam.eu as gateway. The updated datasets include separate estimates for the different components of the evaporative flux (i.e. transpiration, bare-soil evaporation, interception loss, open-water evaporation and snow sublimation), as well as variables like the evaporative stress, potential evaporation, root-zone soil moisture and surface soil moisture. A new dataset using SMOS-based input data of surface soil moisture and vegetation optical depth will also be

  8. Evaporation mitigation using floating modular devices

    NASA Astrophysics Data System (ADS)

    Hassan, M. Mahmudul; Peirson, William Leslie; Neyland, Bryce M.; Fiddis, Nicholas McQuistan

    2015-11-01

    Reducing evaporation losses from open water storages is of paramount importance in the improvement of water security in arid countries, including Australia. Widespread adoption of evaporation mitigation techniques has been prevented by their high capital and maintenance or operating costs. The use of clean, floating recycled materials to mitigate evaporation technique has been investigated systematically at sites within both the coastal and semi-arid zones of Australia. Evaporation reduction systematically increases with the proportion of covered surface. Evaporation is reduced by 43% at coastal site and 37% at arid zone site at the maximum packing densities achievable for a single layer of floating devices. The study highlights the importance of both long-term investigations and the climatic influences in the robust quantification of evaporation mitigation. The effects of solar radiation, temperature, wind speed and relative humidity on the evaporation rate at both study sites have been determined in terms of both the classical Penman model and FAO Penman Monteith model with corresponding pan coefficients quantified. FAO Penman Monteith model better estimates evaporation from the open reference tank.

  9. Representational Issues in Students Learning about Evaporation

    ERIC Educational Resources Information Center

    Tytler, Russell; Prain, Vaughan; Peterson, Suzanne

    2007-01-01

    This study draws on recent research on the central role of representation in learning. While there has been considerable research on students' understanding of evaporation, the representational issues entailed in this understanding have not been investigated in depth. The study explored students' engagement with evaporation phenomena through…

  10. Radioactive Waste Evaporation: Current Methodologies Employed for the Development, Design, and Operation of Waste Evaporators at the Savannah River Site and Hanford Waste Treatment Plant

    SciTech Connect

    Calloway, T.B.

    2003-09-11

    Evaporation of High level and Low Activity (HLW and LAW) radioactive wastes for the purposes of radionuclide separation and volume reduction has been conducted at the Savannah River and Hanford Sites for more than forty years. Additionally, the Savannah River Site (SRS) has used evaporators in preparing HLW for immobilization into a borosilicate glass matrix. This paper will discuss the methodologies, results, and achievements of the SRTC evaporator development program that was conducted in support of the SRS and Hanford WTP evaporator processes. The cross pollination and application of waste treatment technologies and methods between the Savannah River and Hanford Sites will be highlighted. The cross pollination of technologies and methods is expected to benefit the Department of Energy's Mission Acceleration efforts by reducing the overall cost and time for the development of the baseline waste treatment processes.

  11. Molecular Dynamics Simulations of Water Evaporation

    NASA Astrophysics Data System (ADS)

    Wen, Chengyuan; Grest, Gary; Cheng, Shengfeng

    2015-03-01

    The evaporation of water from the liquid/vapor interface is studied via large-scale molecular dynamics simulations for systems of more than a million atoms at 550K and 600K. The TIP4P-2005 water model whose liquid/vapor surface tension is in excellent agreement with experiments is used. Evaporative cooling at the interface is observed from temperature profiles determined from both translational and rotational kinetic energy. During evaporation, the density of water is slightly enhanced near the liquid-vapor interface. The velocity distribution of water molecules in the vapor phase during evaporation at various distances relative to the interface fit a Maxwell-Boltzmann distribution. While our results indicate an imbalance between evaporating and condensing water molecules, local thermal equilibrium is found to hold in addition to mechanical equilibrium. Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.

  12. Quantifying nonisothermal subsurface soil water evaporation

    NASA Astrophysics Data System (ADS)

    Deol, Pukhraj; Heitman, Josh; Amoozegar, Aziz; Ren, Tusheng; Horton, Robert

    2012-11-01

    Accurate quantification of energy and mass transfer during soil water evaporation is critical for improving understanding of the hydrologic cycle and for many environmental, agricultural, and engineering applications. Drying of soil under radiation boundary conditions results in formation of a dry surface layer (DSL), which is accompanied by a shift in the position of the latent heat sink from the surface to the subsurface. Detailed investigation of evaporative dynamics within this active near-surface zone has mostly been limited to modeling, with few measurements available to test models. Soil column studies were conducted to quantify nonisothermal subsurface evaporation profiles using a sensible heat balance (SHB) approach. Eleven-needle heat pulse probes were used to measure soil temperature and thermal property distributions at the millimeter scale in the near-surface soil. Depth-integrated SHB evaporation rates were compared with mass balance evaporation estimates under controlled laboratory conditions. The results show that the SHB method effectively measured total subsurface evaporation rates with only 0.01-0.03 mm h-1difference from mass balance estimates. The SHB approach also quantified millimeter-scale nonisothermal subsurface evaporation profiles over a drying event, which has not been previously possible. Thickness of the DSL was also examined using measured soil thermal conductivity distributions near the drying surface. Estimates of the DSL thickness were consistent with observed evaporation profile distributions from SHB. Estimated thickness of the DSL was further used to compute diffusive vapor flux. The diffusive vapor flux also closely matched both mass balance evaporation rates and subsurface evaporation rates estimated from SHB.

  13. Potable water recovery for spacecraft application by electrolytic pretreatment/air evaporation

    NASA Technical Reports Server (NTRS)

    Wells, G. W.

    1975-01-01

    A process for the recovery of potable water from urine using electrolytic pretreatment followed by distillation in a closed-cycle air evaporator has been developed and tested. Both the electrolytic pretreatment unit and the air evaporation unit are six-person, flight-concept prototype, automated units. Significantly extended wick lifetimes have been achieved in the air evaporation unit using electrolytically pretreated, as opposed to chemically pretreated, urine feed. Parametric test data are presented on product water quality, wick life, process power, maintenance requirements, and expendable requirements.

  14. Sub- and super-Maxwellian evaporation of simple gases from liquid water

    NASA Astrophysics Data System (ADS)

    Kann, Z. R.; Skinner, J. L.

    2016-04-01

    Non-Maxwellian evaporation of light atoms and molecules (particles) such as He and H2 from liquids has been observed experimentally. In this work, we use simulations to study systematically the evaporation of Lennard-Jones particles from liquid water. We find instances of sub- and super-Maxwellian evaporation, depending on the mass of the particle and the particle-water interaction strength. The observed trends are in qualitative agreement with experiment. We interpret these trends in terms of the potential of mean force and the effectiveness and frequency of collisions during the evaporation process. The angular distribution of evaporating particles is also analyzed, and it is shown that trends in the energy from velocity components tangential and normal to the liquid surface must be understood separately in order to interpret properly the angular distributions.

  15. Sub- and super-Maxwellian evaporation of simple gases from liquid water.

    PubMed

    Kann, Z R; Skinner, J L

    2016-04-21

    Non-Maxwellian evaporation of light atoms and molecules (particles) such as He and H2 from liquids has been observed experimentally. In this work, we use simulations to study systematically the evaporation of Lennard-Jones particles from liquid water. We find instances of sub- and super-Maxwellian evaporation, depending on the mass of the particle and the particle-water interaction strength. The observed trends are in qualitative agreement with experiment. We interpret these trends in terms of the potential of mean force and the effectiveness and frequency of collisions during the evaporation process. The angular distribution of evaporating particles is also analyzed, and it is shown that trends in the energy from velocity components tangential and normal to the liquid surface must be understood separately in order to interpret properly the angular distributions. PMID:27389228

  16. Effect of UV irradiation on the evaporation rate of alcohols droplets

    NASA Astrophysics Data System (ADS)

    Korobko, O. V.; Britan, A. V.; Verbinskaya, G. H.; Gavryushenko, D. A.

    2015-06-01

    The effect of ultraviolet irradiation with a wavelength of 390 nm on the evaporation of droplets of the homologous series of alcohols ( n-propanol, n-butanol, n-pentanol, n-heptanol, n-octanol, and n-decanol) at 10, 30, 50, 100, and 200 mm Hg in an atmosphere of dry nitrogen is studied. The values of the evaporation rate of alcohols are calculated with and without irradiation. Starting from n-pentanol, the rate of evaporation grows strongly for droplets of higher alcohols under the effect of low-power irradiation not associated with the heating of the evaporating droplets of alcohols. The obtained results are analyzed by comparing them to experimental data on neutron scattering by alcohols. It is shown that free convection must be considered in order to describe the evaporation process. Expressions of different authors for describing this effect are analyzed.

  17. Marangoni-Benard Convection in a Evaporating Liquid Thin Layer

    NASA Technical Reports Server (NTRS)

    Chai, An-Ti; Zhang, Nengli

    1996-01-01

    Marangoni-Benard convection in evaporating liquid thin layers has been investigated through flow visualization and temperature profile measurement. Twelve liquids, namely ethyl alcohol, methanol, chloroform, acetone, cyclohexane, benzine, methylene chloride, carbon tetrachloride, ethyl acetate, n-pentane, silicone oil (0.65 cSt.), and freon-113, were tested and convection patterns in thin layers of these samples were observed. Comparison among these tested samples shows that some liquids are sensitive to surface contamination from aluminum powder but some are not. The latter is excellent to be used for the investigation of surface-tension driven convection through visualization using the tracer. Two sample liquids, alcohol and freon-113 were particularly selected for systematic study. It was found that the wavelength of Benard cells would not change with thickness of the layer when it evaporates at room temperature. Special attention was focused on cases in which a liquid layer was cooled from below, and some interesting results were obtained. Convection patterns were recorded during the evaporation process and the patterns at certain time frame were compared. Benard cells were observed in thin layers with a nonlinear temperature profile and even with a zero or positive temperature gradient. Wavelength of the cells was found to increase as the evaporation progressed.

  18. Accurate analysis of multicomponent fuel spray evaporation in turbulent flow

    NASA Astrophysics Data System (ADS)

    Rauch, Bastian; Calabria, Raffaela; Chiariello, Fabio; Le Clercq, Patrick; Massoli, Patrizio; Rachner, Michael

    2012-04-01

    The aim of this paper is to perform an accurate analysis of the evaporation of single component and binary mixture fuels sprays in a hot weakly turbulent pipe flow by means of experimental measurement and numerical simulation. This gives a deeper insight into the relationship between fuel composition and spray evaporation. The turbulence intensity in the test section is equal to 10%, and the integral length scale is three orders of magnitude larger than the droplet size while the turbulence microscale (Kolmogorov scales) is of same order as the droplet diameter. The spray produced by means of a calibrated droplet generator was injected in a gas flow electrically preheated. N-nonane, isopropanol, and their mixtures were used in the tests. The generalized scattering imaging technique was applied to simultaneously determine size, velocity, and spatial location of the droplets carried by the turbulent flow in the quartz tube. The spray evaporation was computed using a Lagrangian particle solver coupled to a gas-phase solver. Computations of spray mean diameter and droplet size distributions at different locations along the pipe compare very favorably with the measurement results. This combined research tool enabled further investigation concerning the influencing parameters upon the evaporation process such as the turbulence, droplet internal mixing, and liquid-phase thermophysical properties.

  19. End-evaporation kinetics in living-polymer systems

    NASA Astrophysics Data System (ADS)

    Marques, C. M.; Turner, M. S.; Cates, M. E.

    1993-11-01

    We study theoretically the process of ``end-evaporation'' in living polymer systems, such as wormlike surfactant micelles. End-evaporation occurs when single monomers either break away from, or join onto, a chain end, the rates being described by the (mean-field) rate constants k and k', respectively. Thus the chains can exchange material with one-another via a bath of free monomers. The relaxation of a system of living polymers after a small temperature jump (T-jump) is studied theoretically. The effect of a T-jump is to prepare the system with the wrong mean chain length, which relaxes to its equilibrium value L¯ by end-evaporation. It is found that the number of free monomers in the system relaxes almost completely in a time of order 1/kL¯, while the weight-average chain length, which is the quantity measured in light scattering experiments, relaxes on a time scale τD=4L¯2/k, which is three powers of L¯ longer. We also predict that the stress relaxation after a step strain is dominated by end-evaporation whenever τD≲τrep, where τrep is the reptation (disengagement) time for a chain of length L¯. In this case the stress relaxation is found to be ``stretched exponential'' for times smaller than τD and single exponential for longer times.

  20. Evaporation from Lake Mead, Nevada and Arizona, March 2010 through February 2012

    USGS Publications Warehouse

    Moreo, Michael T.; Swancar, Amy

    2013-01-01

    Evaporation from Lake Mead was measured using the eddy-covariance method for the 2-year period starting March 2010 and ending February 2012. When corrected for energy imbalances, annual eddy-covariance evaporation was 2,074 and 1,881 millimeters (81.65 and 74.07 inches), within the range of previous estimates. There was a 9-percent decrease in the evaporation rate and a 10-percent increase in the lake surface area during the second year of the study compared to the first. These offsetting factors resulted in a nearly identical 720 million cubic meters (584,000 acre feet) evaporation volume for both years. Monthly evaporation rates were best correlated with wind speed, vapor pressure difference, and atmospheric stability. Differences between individual monthly evaporation and mean monthly evaporation were as much as 20 percent. Net radiation provided most of the energy available for evaporative processes; however, advected heat from the Colorado River was an important energy source during the second year of the study. Peak evaporation lagged peak net radiation by 2 months because a larger proportion of the net radiation that reaches the lake goes to heating up the water column during the spring and summer months. As most of this stored energy is released, higher evaporation rates are sustained during fall months even though net radiation declines. The release of stored heat also fueled nighttime evaporation, which accounted for 37 percent of total evaporation. The annual energy-balance ratio was 0.90 on average and varied only 0.01 between the 2 years, thus implying that 90 percent of estimated available energy was accounted for by turbulent energy measured using the eddy-covariance method. More than 90 percent of the turbulent-flux source area represented the open-water surface, and 94 percent of 30-minute turbulent-flux measurements originated from wind directions where the fetch ranged from 2,000 to 16,000 meters. Evaporation uncertainties were estimated to be 5

  1. Evaporation from Near-Drift Fractured Rock Surfaces

    NASA Astrophysics Data System (ADS)

    Manepally, C.; Fedors, R. W.; Or, D.; Das, K.

    2007-12-01

    The amount of water entering emplacement drifts from a fractured unsaturated rock is an important variable for performance evaluation of a potential high-level radioactive waste repository at Yucca Mountain, Nevada. Water entering the drifts as liquid or gas may enhance waste package corrosion rates and transport released radionuclides. Liquid water in form of droplets may emerge from fractures, or flow along the drift wall and potentially evaporate and condense at other locations. Driven by pressure and temperature gradients, vapor may be transported along fractures, or liquid water may evaporate directly from the matrix. Within the drift, heat-driven convection may redistribute the moisture leading to condensation at other locations. The geometry of the evaporation front around the drift is not fully understood and this, in turn, influences processes related to reflux, rewetting as the thermal pulse dissipates. Existing models focus on processes in the porous media (e.g., two-phase dual-permeability models for matrix and fractures), or on processes in the drift (e.g., gas-phase computational fluid dynamics models). This study focuses on the boundary between these two domains, and the corresponding models, where evaporation at the solid rock/drift air interface appears to play an important role. Studies have shown that evaporation from porous media is a complex process sensitive to factors such as (i) hydrological properties of the porous media, (ii) pressure gradients in the porous media, (iii) texture of the interface or boundary, (iv) local vapor and temperature gradients, and (v) convective flow rate and boundary layer transfer. Experimental observations based on passive monitoring at Yucca Mountain have shown that the formation surrounding the drift is able to provide and transport large amounts of water vapor over a relatively short period. This study will examine the basic processes that govern evaporation in the unsaturated rock surrounding drifts for

  2. RECYCLING NICKEL ELECTROPLATING RINSE WATERS BY LOW TEMPERATURE EVAPORATION AND REVERSE OSMOSIS

    EPA Science Inventory

    Low temperature evaporation and reverse osmosis systems were each evaluated (on a pilot scale) on their respective ability to process rinse water collected from a nickel electroplating operation. Each system offered advantages under specific operating conditions. The low temperat...

  3. RECYCLING NICKEL ELECTROPLATING RINSE WATERS BY LOW TEMPERATURE EVAPORATION AND REVERSE OSMOSIS

    EPA Science Inventory

    Low temperature evaporation and reverse osmosis systems were each evaluated (on a pilot scale) on their respective ability to process rinse water collected from a nickel electroplating operation. ach system offered advantages under specific operating conditions. he low temperatur...

  4. Dynamics of Soil Water Evaporation during Soil Drying: Laboratory Experiment and Numerical Analysis

    PubMed Central

    Han, Jiangbo; Zhou, Zhifang

    2013-01-01

    Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68 cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71 cm during stage 3. PMID:24489492

  5. Dynamics of soil water evaporation during soil drying: laboratory experiment and numerical analysis.

    PubMed

    Han, Jiangbo; Zhou, Zhifang

    2013-01-01

    Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68 cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71 cm during stage 3. PMID:24489492

  6. Mergers, cooling flows, and evaporation

    NASA Technical Reports Server (NTRS)

    Sparks, W. B.

    1993-01-01

    Mergers (the capture of cold gas, especially) can have a profound influence on the hot coronal gas of early-type galaxies and clusters, potentially inducing symptoms hitherto attributed to a cooling flow, if thermal conduction is operative in the coronal plasma. Heat can be conducted from the hot phase into the cold phase, simultaneously ionizing the cold gas to make optical filaments, while locally cooling the coronal gas to mimic a cooling-flow. If there is heat conduction, though, there is no standard cooling-flow since radiative losses are balanced by conduction and not mass deposition. Amongst the strongest observational support for the existence of cooling-flows is the presence of intermediate temperature gas with x-ray emission-line strengths in agreement with cooling-flow models. Here, x-ray line strengths are calculated for this alternative model, in which mergers are responsible for the observed optical and x-ray properties. Since gas around 10(exp 4) K is thermally stable, the cold cloud need not necessarily evaporate and hydrostatic solutions exist. Good agreement with the x-ray data is obtained. The relative strengths of intermediate temperature x-ray emission lines are in significantly better agreement with a simple conduction model than with published cooling-flow models. The good agreement of the conduction model with optical, infrared and x-ray data indicates that significantly more theoretical effort into this type of solution would be profitable.

  7. Evaporative losses from soils covered by physical and different types of biological soil crusts

    USGS Publications Warehouse

    Chamizo, S.; Cantón, Y.; Domingo, F.; Belnap, J.

    2013-01-01

    Evaporation of soil moisture is one of the most important processes affecting water availability in semiarid ecosystems. Biological soil crusts, which are widely distributed ground cover in these ecosystems, play a recognized role on water processes. Where they roughen surfaces, water residence time and thus infiltration can be greatly enhanced, whereas their ability to clog soil pores or cap the soil surface when wetted can greatly decrease infiltration rate, thus affecting evaporative losses. In this work, we compared evaporation in soils covered by physical crusts, biological crusts in different developmental stages and in the soils underlying the different biological crust types. Our results show that during the time of the highest evaporation (Day 1), there was no difference among any of the crust types or the soils underlying them. On Day 2, when soil moisture was moderately low (11%), evaporation was slightly higher in well-developed biological soil crusts than in physical or poorly developed biological soil crusts. However, crust removal did not cause significant changes in evaporation compared with the respective soil crust type. These results suggest that the small differences we observed in evaporation among crust types could be caused by differences in the properties of the soil underneath the biological crusts. At low soil moisture (<6%), there was no difference in evaporation among crust types or the underlying soils. Water loss for the complete evaporative cycle (from saturation to dry soil) was similar in both crusted and scraped soils. Therefore, we conclude that for the specific crust and soil types tested, the presence or the type of biological soil crust did not greatly modify evaporation with respect to physical crusts or scraped soils.

  8. The effect of surface texture on evaporation, infiltration and storage properties of paved surfaces.

    PubMed

    Mansell, M; Rollet, F

    2009-01-01

    This paper concerns an investigation of evaporation, infiltration and detention storage on paved surfaces and the effect of surface texture and microtopography on these processes. A numerical model has been developed which represents the evaporation and infiltration processes on a nominally impervious surface as well as the depression storage due to the surface microtopography. The model was applied to semi-randomly generated surfaces and the results show the relationship between surface microtopography and initial storage losses. PMID:19587404

  9. Comparison of Total Evaporation (TE) and Direct Total Evaporation (DTE) methods in TIMS by using NBL CRMs

    NASA Astrophysics Data System (ADS)

    Hasözbek, Altug; Mathew, Kattathu; Wegener, Michael

    2013-04-01

    The total evaporation (TE) is a well-established analytical method for safeguards measurement of uranium and plutonium isotope-amount ratios using the thermal ionization mass spectrometry (TIMS). High accuracy and precision isotopic measurements find many applications in nuclear safeguards, for e.g. assay measurements using isotope dilution mass spectrometry. To achieve high accuracy and precision in TIMS measurements, mass dependent fractionation effects are minimized by either the measurement technique or changes in the hardware components that are used to control sample heating and evaporation process. At NBL, direct total evaporation (DTE) method on the modified MAT261 instrument, uses the data system to read the ion signal intensity and its difference from a pre-determined target intensity, is used to control the incremental step at which the evaporation filament is heated. The feedback and control is achieved by proprietary hardware from SPECTROMAT that uses an analog regulator in the filament power supply with direct feedback of the detector intensity. Compared to traditional TE method on this instrument, DTE provides better precision (relative standard deviation, expressed as a percent) and accuracy (relative difference, expressed as a percent) of 0.05 to 0.08 % for low enriched and high enriched NBL uranium certified reference materials.

  10. Evaporative modeling for idealized lithographic pores

    NASA Astrophysics Data System (ADS)

    Oinuma, Ryoji; Best, Frederick

    2002-01-01

    As a demand for the high performance and small size electronics devices increased, the heat removal from those electronic devices for space use is getting critical factor more than devices on the earth due to the limitation of the size. The purpose of this paper is to show a study of optimized size of coherent pores or slits in the evaporative wick of a heat pipe to cool down the high heat flux density heat source. Our system considered in this paper consists of a plate heat source, the evaporative wick with coherent pores and conducting walls connecting between the heat source and the evaporator. The evaporation rate of working fluid along the meniscus interface in a micro-order pore or slit was calculated based on the kinetic theory and the statistical rate theory to find a proper diameter of pores to cool down the heat source effectively. The results show the smaller diameter of pores is preferred to achieve the smallest total size of the evaporator although it will involve the cost issue. As a demand for the high performance and small size electronics devices increased, the heat removal from those electronic devices for space use is getting critical factor more than devices on the earth due to the limitation of the size. The purpose of this paper is to show a study of optimized size of coherent pores or slits in the evaporative wick of a heat pipe to cool down the high heat flux density heat source. Our system considered in this paper consists of a plate heat source, the evaporative wick with coherent pores and conducting walls connecting between the heat source and the evaporator. The evaporation rate of working fluid along the meniscus interface in a micro-order pore or slit was calculated based on the kinetic theory and the statistical rate theory to find a proper diameter of pores to cool down the heat source effectively. The results show that the smaller diameter of pores uses the pore for evaporation effectively and is preferred to achieve the smallest

  11. Potentiating action of MKC-242, a selective 5-HT1A receptor agonist, on the photic entrainment of the circadian activity rhythm in hamsters

    PubMed Central

    Moriya, T; Yoshinobu, Y; Ikeda, M; Yokota, S; Akiyama, M; Shibata, S

    1998-01-01

    Serotonergic projections from the midbrain raphe nuclei to the suprachiasmatic nuclei (SCN) are known to regulate the photic entrainment of circadian clocks. However, it is not known which 5-hydroxytryptamine (5-HT) receptor subtypes are involved in the circadian regulation. In order to verify the role of 5-HT1A receptors, we examined the effects of 5-{3-[((2S)-1,4-benzodioxan-2-ylmethyl)amino]propoxy}-1,3-benzodioxole HCl (MKC-242), a selective 5-HT1A receptor agonist, on photic entrainment of wheel-running circadian rhythms of hamsters.MKC-242 (3 mg kg−1, i.p.) significantly accelerated the re-entrainment of wheel-running rhythms to a new 8 h delayed or advanced light-dark cycle.MKC-242 (3 mg kg−1, i.p.) also potentiated the phase advance of the wheel-running rhythm produced by low (5 lux) or high (60 lux) intensity light pulses. In contrast, 8-hydroxy-dipropylaminotetralin (8-OH-DPAT)(5 mg kg−1, i.p.), a well known 5-HT1A/5-HT7 receptor agonist, only suppressed low intensity (5 lux) light-induced phase advances.The potentiating actions of MKC-242 on light pulse-induced phase advances were observed even when injected 20 or 60 min after the light exposure.The potentiating action of MKC-242 was antagonized by WAY100635, a selective 5-HT1A receptor blocker, but not by ritanserin, a 5-HT2/5-HT7 receptor blocker, indicating that MKC-242 is activating 5-HT1A receptors.Light pulse-induced c-fos expression in the SCN and the intergeniculate leaflet (IGL) were unaffected by MKC-242 (3 mg kg−1, i.p.).HPLC analysis demonstrated that MKC-242 (3 mg kg−1, i.p.) decreased the 5-HIAA content in the SCN.The present results suggest that presynaptic 5-HT1A receptor activation may be involved in the potentiation of photic entrainment by MKC-242 in hamsters. PMID:9863658

  12. Potentiating action of MKC-242, a selective 5-HT1A receptor agonist, on the photic entrainment of the circadian activity rhythm in hamsters.

    PubMed

    Moriya, T; Yoshinobu, Y; Ikeda, M; Yokota, S; Akiyama, M; Shibata, S

    1998-11-01

    Serotonergic projections from the midbrain raphe nuclei to the suprachiasmatic nuclei (SCN) are known to regulate the photic entrainment of circadian clocks. However, it is not known which 5-hydroxytryptamine (5-HT) receptor subtypes are involved in the circadian regulation. In order to verify the role of 5-HT1A receptors, we examined the effects of 5-¿3-[((2S)-1,4-benzodioxan-2-ylmethyl)amino]-propoxy¿-1,3-b enzodioxole HCl (MKC-242), a selective 5-HT1A receptor agonist, on photic entrainment of wheel-running circadian rhythms of hamsters. MKC-242 (3 mg kg(-1), i.p.) significantly accelerated the re-entrainment of wheel-running rhythms to a new 8 h delayed or advanced light-dark cycle. MKC-242 (3 mg kg(-1), i.p.) also potentiated the phase advance of the wheel-running rhythm produced by low (5 lux) or high (60 lux) intensity light pulses. In contrast, 8-hydroxydipropylaminotetralin (8-OH-DPAT)(5 mg kg(-1), i.p.), a well known 5-HT1A/5-HT7 receptor agonist, only suppressed low intensity (5 lux) light-induced phase advances. The potentiating actions of MKC-242 on light pulse-induced phase advances were observed even when injected 20 or 60 min after the light exposure. The potentiating action of MKC-242 was antagonized by WAY100635, a selective 5-HT1A receptor blocker, but not by ritanserin, a 5-HT2/5-HT7 receptor blocker, indicating that MKC-242 is activating 5-HT1A receptors. Light pulse-induced c-fos expression in the SCN and the intergeniculate leaflet (IGL) were unaffected by MKC-242 (3 mg kg(-1), i.p.). HPLC analysis demonstrated that MKC-242 (3 mg kg(-1), i.p.) decreased the 5-HIAA content in the SCN. The present results suggest that presynaptic 5-HT1A receptor activation may be involved in the potentiation of photic entrainment by MKC-242 in hamsters. PMID:9863658

  13. Water repellency diminishes peatland evaporation after wildfire

    NASA Astrophysics Data System (ADS)

    Kettridge, N.; Lukenbach, M.; Hokanson, K. J.; Devito, K. J.; Petrone, R. M.; Hopkinson, C.; Waddington, J. M.

    2015-12-01

    Peatlands are a critically important global carbon reserve. There is increasing concern that such ecosystems are vulnerable to projected increases in wildfire severity under a changing climate. Severe fires may exceed peatland ecological resilience resulting in the long term degradation of this carbon store. Evaporation provides the primary mechanisms of water loss from such environments and can regulate the ecological stress in the initial years after wildfire. We examine variations in evaporation within burned peatlands after wildfire through small scale chamber and large scale remote sensing measurements. We show that near-surface water repellency limits peatland evaporation in these initial years post fire. Water repellent peat produced by the fire restricts the supply of water to the surface, reducing evaporation and providing a strong negative feedback to disturbance. This previously unidentified feedback operates at the landscape scale. High surface temperatures that result from large reductions in evaporation within water repellent peat are observed across the 60,000 ha burn scar three months after the wildfire. This large scale reduction in evaporation promotes high water table positions at a landscape scale which limits the rate of peat decomposition and supports the post fire ecohydrological recovery of the peatlands. However, severe burns are shown to exceed this negative feedback response. Deep burns at the peatland margins remove the hydrophobic layer, increasing post fire evaporation and leaving the peatland vulnerable to drying and associated ecological shifts.

  14. Vapor compression evaporator concentrates, recovers alcohol

    SciTech Connect

    Miller, M.N.; Robe, K.; Bacchetti, J.A.

    1982-11-01

    This article focuses on presenting a solution to the high energy cost of operating a steam heated, single effect evaporator used by Monsanto Industrial Chemical Company at a plant in Seattle, Wash., to produce vanillin from pulp and paper mill sulfite. Use of the single effect flash evaporator resulted in high energy usage due not only to the ''single effect'' use of steam, but also because energy consumption was reduced only slightly at low operating rates. The solution to this problem was the replacement of the single effect evaporator with a vapor recompression evaporator. Operating for over 1 1/2 years, the vapor recompression evaporator system has had no significant maintenance problems. The system operates with only 1/60th the steam consumption and 15% of the total energy consumption of the previous evaporator and has had no tube fouling. Also, since the distillate is condensed within the evaporator, less cooling water is required, allowing two heat exchangers to be taken out of service. When operating at less than design capacity, the energy consumption drops almost linearly with the feed rate. At low feed rates, a by-pass valve unloads the compressor to reduce energy consumption. Total energy consumption, now 15% of the previous level, results in an estimated pay-back of less than three years.

  15. Tank 26 Evaporator Feed Pump Transfer Analysis

    SciTech Connect

    Tamburello, David; Dimenna, Richard; Lee, Si

    2009-02-11

    The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics methods to determine the amount of entrained sludge solids pumped out of the tank to the evaporator with the downcomer turned on. The analysis results showed that, for the maximum and minimum supernate levels in Tank 26 (252.5 and 72 inches above the sludge layer, respectively), the evaporator feed pump will entrain between 0.03 and 0.1 wt% sludge undissolved solids weight fraction into the eductor, respectively, and therefore are an order of magnitude less than the 1.0 wt% undissolved solids loading criteria to feed the evaporator. Lower tank liquid levels, with respect to the sludge layer, result in higher amounts of sludge entrainment due to the increased velocity of the plunging jets from the downcomer and evaporator feed pump bypass as well as decreased dissipation depth. Revision 1 clarifies the analysis presented in Revision 0 and corrects a mathematical error in the calculations for Table 4.1 in Revision 0. However, the conclusions and recommendations of the analysis do not change for Revision 1.

  16. Century Scale Evaporation Trend: An Observational Study

    NASA Technical Reports Server (NTRS)

    Bounoui, Lahouari

    2012-01-01

    Several climate models with different complexity indicate that under increased CO2 forcing, runoff would increase faster than precipitation overland. However, observations over large U.S watersheds indicate otherwise. This inconsistency between models and observations suggests that there may be important feedbacks between climate and land surface unaccounted for in the present generation of models. We have analyzed century-scale observed annual runoff and precipitation time-series over several United States Geological Survey hydrological units covering large forested regions of the Eastern United States not affected by irrigation. Both time-series exhibit a positive long-term trend; however, in contrast to model results, these historic data records show that the rate of precipitation increases at roughly double the rate of runoff increase. We considered several hydrological processes to close the water budget and found that none of these processes acting alone could account for the total water excess generated by the observed difference between precipitation and runoff. We conclude that evaporation has increased over the period of observations and show that the increasing trend in precipitation minus runoff is correlated to observed increase in vegetation density based on the longest available global satellite record. The increase in vegetation density has important implications for climate; it slows but does not alleviate the projected warming associated with greenhouse gases emission.

  17. Evaporative Heat Transfer Mechanisms within a Heat Melt Compactor

    NASA Technical Reports Server (NTRS)

    Golliher, Eric L.; Gotti, Daniel J.; Rymut, Joseph Edward; Nguyen, Brian K; Owens, Jay C.; Pace, Gregory S.; Fisher, John W.; Hong, Andrew E.

    2013-01-01

    This paper will discuss the status of microgravity analysis and testing for the development of a Heat Melt Compactor (HMC). Since fluids behave completely differently in microgravity, the evaporation process for the HMC is expected to be different than in 1-g. A thermal model is developed to support the design and operation of the HMC. Also, low-gravity aircraft flight data is described to assess the point at which water may be squeezed out of the HMC during microgravity operation. For optimum heat transfer operation of the HMC, the compaction process should stop prior to any water exiting the HMC, but nevertheless seek to compact as much as possible to cause high heat transfer and therefore shorter evaporation times.

  18. Tracing Chromospheric Evaporation in Radio and Soft X-rays

    NASA Technical Reports Server (NTRS)

    Aschwanden, Markus J.

    1997-01-01

    There are three publications in refereed journals and several presentations at scientific conferences resulted from this work, over a period of 6 months during 1995/1996. In the first paper, the discovery of the chromospheric evaporation process at radio wavelengths is described. In the second paper, the radio detection is used to quantify electron densities in the upflowing heated plasma in flare loops, which is then compared with independent other density measurements from soft X-rays, or the plasma frequency of electron beams originating in the acceleration region. In the third paper, the diagnostic results of the chromospheric evaporation process are embedded into a broader picture of a standard flare scenario. Abstracts of these three papers are attached.

  19. Reactive evaporation of anomalous blue VO/sub 2/

    SciTech Connect

    Case, F.C.

    1987-04-15

    Thin films of vanadium dioxide exhibit a thermally induced semiconductor-to-metal phase transition near 67/sup 0/ C. In most deposition conditions, the transition is accompanied by large changes in optical properties at infrared wavelengths, but with only slight visible contrast. Recently, reactive evaporation at high temperatures and in stringent process conditions of so-called blue VO/sub 2/ has been reported (G. A. Nyberg and R. A. Buhrman, J. Vac. Sci. Technol. A 2, 301 (1984)). These films exhibit a striking blue-to-red transition in transmitted light. In this paper, a new technique for thin-film growth of anomalous vanadium dioxide will be presented. The primary steps in the process are the reactive evaporation of vanadium oxide at ambient temperature followed by anneal in flowing oxygen. Optical and microstructural data for material deposited on sapphire and fused quartz substrates will be compared to standard vanadium oxide.

  20. Water sources, mixing and evaporation in the Akyatan lagoon, Turkey

    NASA Astrophysics Data System (ADS)

    Lécuyer, C.; Bodergat, A.-M.; Martineau, F.; Fourel, F.; Gürbüz, K.; Nazik, A.

    2012-12-01

    Akyatan lagoon, located southeast of Turkey along the Mediterranean coast, is a choked and hypersaline lagoon, and hosts a large and specific biodiversity including endangered sea turtles and migrating birds. Physicochemical properties of this lagoon were investigated by measuring temperature, salinity, and hydrogen and oxygen isotope ratios of its waters at a seasonal scale during years 2006 and 2007. Winter and spring seasons were dominated by mixing processes between freshwaters and Mediterranean seawater. The majority of spring season waters are formed by evapoconcentration of brackish water at moderate temperatures of 22 ± 2 °C. During summer, hypersaline waters result from evaporation of seawater and brackish waters formed during spring. Evaporation over the Akyatan lagoon reaches up to 76 wt% based on salinity measurements and operated with a dry (relative humidity of 0.15-0.20) and hot (44 ± 6 °C) air. These residual waters were characterized by the maximal seasonal isotopic enrichment in both deuterium and 18O relative to VSMOW. During autumn, most lagoonal waters became hypersaline and were formed by evaporation of waters that had isotopic compositions and salinities close to that of seawater. These autumnal hypersaline waters result from an air humidity close to 0.45 and an atmospheric temperature of evaporation of 35 ± 5 °C, which are responsible for up to 71 wt% of evaporation, with restricted isotopic enrichments relative to VSMOW. During the warm seasons, the combination of air humidity, wind velocity and temperature were responsible for a large kinetic component in the total isotopic fractionation between water liquid and water vapour.

  1. On the evaporation of ammonium sulfate solution

    PubMed Central

    Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

    2009-01-01

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 ± 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor–liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly. PMID:19861551

  2. Thermocapillary flow about an evaporating meniscus

    NASA Technical Reports Server (NTRS)

    Schmidt, G. R.; Chung, T. J.

    1992-01-01

    The steady motion and thermal behavior of an evaporating superheated liquid in a small cavity bounded by isothermal sidewalls is examined. Scaling analyses and a two-dimensional finite element model are used to investigate the influence of thermocapillarity, buoyancy, and temperature-dependent mass flux on flowfield, interfacial heat transfer, and meniscus morphology. Numerical investigations indicate the existence of two counter-rotating cells symmetric about the cavity center. Results also show that evaporation tends to counteract this circulation by directing flow toward the hotter sidewalls. Although thermocapillarity and evaporation yield different flowfield distributions, both effects tend to increase interfacial temperature and heat transfer.

  3. On the evaporation of ammonium sulfate solution

    SciTech Connect

    Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

    2009-07-16

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 {+-} 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

  4. Heat and Mass Exchange of a Drop of a Solution Subjected to a Combined Energy Action Under Conditions of Deepening of the Evaporation Zone

    NASA Astrophysics Data System (ADS)

    Akulich, P. V.

    2016-05-01

    A model of the heat and mass exchange in the evaporation of drops moving in the carrying gas phase of a solution subjected to the combined energy action of a convective heat flow and electromagnetic infrared and microwave radiations under conditions where the size of the drops changes at the low-temperature stage of their evaporation and the evaporation zone deepens at the high-temperature stage of the evaporation process has been formulated. Kinetic dependences and features of the movement of the evaporation boundary in the process of dehydration of the indicated drops have been determined.

  5. Heat and Mass Exchange of a Drop of a Solution Subjected to a Combined Energy Action Under Conditions of Deepening of the Evaporation Zone

    NASA Astrophysics Data System (ADS)

    Akulich, P. V.

    2016-06-01

    A model of the heat and mass exchange in the evaporation of drops moving in the carrying gas phase of a solution subjected to the combined energy action of a convective heat flow and electromagnetic infrared and microwave radiations under conditions where the size of the drops changes at the low-temperature stage of their evaporation and the evaporation zone deepens at the high-temperature stage of the evaporation process has been formulated. Kinetic dependences and features of the movement of the evaporation boundary in the process of dehydration of the indicated drops have been determined.

  6. The mechanism of evaporation from sand columns with restricted and unrestricted water tables using deuterium under turbulent airflow conditions

    NASA Astrophysics Data System (ADS)

    Shimojima, Eiichi; Curtis, Alan A.; Turner, Jeffrey V.

    1990-09-01

    Evaporation experiments from sand columns with restricted and unrestricted water tables were carried out to elucidate the mechanism of evaporation from bare land. Turbulent airflow was applied to the exposed surface layer. The transient development of the deuterium composition of liquid water in the sand columns was measured by a microdistillation technique during the experiments. Turbulent airflow affected the evaporative process of water vapour transfer and the deuterium distribution at relatively shallow depths in the columns. The attainment of a steady evaporation rate and deuterium profile was not obtained in either the restricted or unrestricted water table cases until significant time had elapsed. In the unrestricted water table case, the transient processes of evaporation rate, depth of the evaporation front, water table depth and the development of the deuterium concentration profile show a characteristic behaviour that may be described by a similarity solution for part of the experimental duration. Significant enrichment of deuterium occurs in the liquid-vapour region and at the upper zone of the liquid region with time. The isotopic enrichment does not affect the physical process of evaporation of liquid water. Information on the transient development of the deuterium concentration profile is very useful for understanding the nature of liquid water and water vapour movement in the columns, and estimation of the depth of the evaporating front is an important index in bare land evaporation.

  7. Simulated Waste Testing Of Glycolate Impacts On The 2H-Evaporator System

    SciTech Connect

    Martino, C. J.

    2013-08-13

    Glycolic acid is being studied as a total or partial replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste tank farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the tank farm were addressed via a literature review, but several outstanding issues remained. This report documents the non-radioactive simulant tests impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The testing for which non-radioactive simulants could be used involved the following: the partitioning of glycolate into the evaporator condensate, the impacts of glycolate on metal solubility, and the impacts of glycolate on the formation and dissolution of sodium aluminosilicate scale within the evaporator. The following are among the conclusions from this work: Evaporator condensate did not contain appreciable amounts of glycolate anion. Of all tests, the highest glycolate concentration in the evaporator condensate was 0.38 mg/L. A significant portion of the tests had glycolate concentration in the condensate at less than the limit of quantification (0.1 mg/L). At ambient conditions, evaporator testing did not show significant effects of glycolate on the soluble components in the evaporator concentrates. Testing with sodalite solids and silicon containing solutions did not show significant effects of glycolate on sodium aluminosilicate formation or dissolution.

  8. Experimental study on the double-evaporator thermosiphon for cooling HTS (high temperature superconductor) system

    NASA Astrophysics Data System (ADS)

    Lee, Junghyun; Ko, Junseok; Kim, Youngkwon; Jeong, Sangkwon; Sung, Taehyun; Han, Younghee; Lee, Jeong-Phil; Jung, Seyong

    2009-08-01

    A cryogenic thermosiphons is an efficient heat transfer device between a cryocooler and a thermal load that is to be cooled. This paper presents an idea of thermosiphon which contains two vertically-separated evaporators. This unique configuration of the thermosiphon is suitable for the purpose of cooling simultaneously two superconducting bearings of the HTS (high temperature superconducting) flywheel system at the same temperature. A so-called double-evaporator thermosiphon was designed, fabricated and tested using nitrogen as the working fluid under sub-atmospheric pressure condition. The interior thermal condition of the double-evaporator thermosiphon was examined in detail during its cool-down process according to the internal thermal states. The double-evaporator thermosiphon has operated successfully at steady-state operation under sub-atmospheric pressure. At the heat flow of 10.6 W, the total temperature difference of the thermosiphon was only 1.59 K and the temperature difference between the evaporators was 0.64 K. The temperature difference of two evaporators is attributed to the conductive thermal resistance of the adiabatic section between the evaporators. The method to reduce this temperature difference has been investigated and presented in this paper. The proper area selection of condenser, evaporator 1, and evaporator 2 was studied by using thermal resistance model to optimize the performance of a thermosiphon. The superior heat transfer characteristic of the double-evaporator thermosiphon without involving any cryogenic pump can be a great potential advantage for cooling HTS bulk modules that are separated vertically.

  9. Development, validation and application of a hydrophilic interaction liquid chromatography-evaporative light scattering detection based method for process control of hydrolysis of xylans obtained from different agricultural wastes.

    PubMed

    Li, Fangbing; Wang, Hui; Xin, Huaxia; Cai, Jianfeng; Fu, Qing; Jin, Yu

    2016-12-01

    Purified standards of xylooligosaccharides (XOSs) (DP2-6) were first prepared from a mixture of XOSs using solid phase extraction (SPE), followed by semi-preparative liquid chromatography both under hydrophilic interaction liquid chromatography (HILIC) modes. Then, an accurate quantitative analysis method based on hydrophilic interaction liquid chromatography-evaporative light scattering detection (HILIC-ELSD) was developed and validated for simultaneous determination of xylose (X1), xylobiose (X2), xylotriose (X3), xylotetraose (X4), xylopentaose (X5), and xylohexaose (X6). This developed HILIC-ELSD method was applied to the comparison of different hydrolysis methods for xylans and assessment of XOSs contents from different agricultural wastes. The result indicated that enzymatic hydrolysis was preferable with fewer by-products and high XOSs yield. The XOSs yield (48.40%) from sugarcane bagasse xylan was the highest, showing conversions of 11.21g X2, 12.75g X3, 4.54g X4, 13.31g X5, and 6.78g X6 from 100g xylan. PMID:27374519

  10. Evaporation analysis for Tank SX-104

    SciTech Connect

    Barrington, C.A.

    1994-10-01

    Decreases in historical interstitial liquid level measurements in tank SX-104 were compared to predictions of a numerical model based upon diffusion of water through a porous crust. The analysis showed that observed level decreases could be explained by evaporation.

  11. Potential Evaporation in North America Through 2100

    NASA Video Gallery

    This animation shows the projected increase in potential evaporation through the year 2100, relative to 1980, based on the combined results of multiple climate models. The maximum increase across N...

  12. Effects of nanoparticles on nanofluid droplet evaporation

    SciTech Connect

    Chen, Ruey-Hung; Phuoc, Tran X.; Martello, Donald

    2010-09-01

    Laponite, Fe2O3 and Ag nanoparticles were added to deionized water to study their effect of evaporation rates. The results show that these nanofluid droplets evaporate at different rates (as indicated by the evaporation rate constant K in the well known D2-law) from the base fluid. Different particles lead to different values of K. As the particle concentration increases due to evaporation. K values of various Ag and Fe2O3 nanofluids go through a transition from one value to another, further demonstrating the effect of increasing nanoparticle concentration. The implication for the heat of vaporization (hfg) is discussed.

  13. Evaporative cooling of microscopic water droplets in vacuo: Molecular dynamics simulations and kinetic gas theory.

    PubMed

    Schlesinger, Daniel; Sellberg, Jonas A; Nilsson, Anders; Pettersson, Lars G M

    2016-03-28

    In the present study, we investigate the process of evaporative cooling of nanometer-sized droplets in vacuum using molecular dynamics simulations with the TIP4P/2005 water model. The results are compared to the temperature evolution calculated from the Knudsen theory of evaporation which is derived from kinetic gas theory. The calculated and simulation results are found to be in very good agreement for an evaporation coefficient equal to unity. Our results are of interest to experiments utilizing droplet dispensers as well as to cloud micro-physics. PMID:27036456

  14. Evaporative cooling of microscopic water droplets in vacuo: Molecular dynamics simulations and kinetic gas theory

    NASA Astrophysics Data System (ADS)

    Schlesinger, Daniel; Sellberg, Jonas A.; Nilsson, Anders; Pettersson, Lars G. M.

    2016-03-01

    In the present study, we investigate the process of evaporative cooling of nanometer-sized droplets in vacuum using molecular dynamics simulations with the TIP4P/2005 water model. The results are compared to the temperature evolution calculated from the Knudsen theory of evaporation which is derived from kinetic gas theory. The calculated and simulation results are found to be in very good agreement for an evaporation coefficient equal to unity. Our results are of interest to experiments utilizing droplet dispensers as well as to cloud micro-physics.

  15. Evaporative cooling of microscopic water droplets in vacuo: Molecular dynamics simulations and kinetic gas theory

    DOE PAGESBeta

    Schlesinger, Daniel; Sellberg, Jonas A.; Nilsson, Anders; Pettersson, Lars G. M.

    2016-03-22

    In the present study, we investigate the process of evaporative cooling of nanometer-sized droplets in vacuum using molecular dynamics simulations with the TIP4P/2005 water model. The results are compared to the temperature evolution calculated from the Knudsen theory of evaporation which is derived from kinetic gas theory. The calculated and simulation results are found to be in very good agreement for an evaporation coefficient equal to unity. Lastly, our results are of interest to experiments utilizing droplet dispensers as well as to cloud micro-physics.

  16. Evaporation study at Warm Springs Reservoir, Oregon

    USGS Publications Warehouse

    Harris, D.D.

    1968-01-01

    The mass transfer-water budget method of computing reservoir evaporation was tested on Warm Springs Reservoir, whose contents and surface area change greatly from early spring to late summer. The mass-transfer coefficient computed for the reservoir is two to three times greater than expected and results in a computed evaporation much greater than that from a land pan. Because of the remoteness of the area, the recommended study technique was modified, which could have reduced the accuracy of the results.

  17. Diffusion Of Mass In Evaporating Multicomponent Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1992-01-01

    Report summarizes study of diffusion of mass and related phenomena occurring in evaporation of dense and dilute clusters of drops of multicomponent liquids intended to represent fuels as oil, kerosene, and gasoline. Cluster represented by simplified mathematical model, including global conservation equations for entire cluster and conditions on boundary between cluster and ambient gas. Differential equations of model integrated numerically. One of series of reports by same authors discussing evaporation and combustion of sprayed liquid fuels.

  18. High-Capacity Heat-Pipe Evaporator

    NASA Technical Reports Server (NTRS)

    Oren, J. A.; Duschatko, R. J.; Voss, F. E.; Sauer, L. W.

    1989-01-01

    Heat pipe with cylindrical heat-input surface has higher contact thermal conductance than one with usual flat surface. Cylindrical heat absorber promotes nearly uniform flow of heat into pipe at all places around periphery of pipe, helps eliminate hotspots on heat source. Lugs in aluminum pipe carry heat from outer surface to liquid oozing from capillaries of wick. Liquid absorbs heat, evaporates, and passes out of evaporator through interlug passages.

  19. Modeling Evaporation of Drops of Different Kerosenes

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth

    2007-01-01

    A mathematical model describes the evaporation of drops of a hydrocarbon liquid composed of as many as hundreds of chemical species. The model is intended especially for application to any of several types of kerosenes commonly used as fuels. The concept of continuous thermodynamics, according to which the chemical composition of the evaporating multicomponent liquid is described by use of a probability distribution function (PDF). However, the present model is more generally applicable than is its immediate predecessor.

  20. Evaporation duct communication: Test plan, part 2

    NASA Astrophysics Data System (ADS)

    Anderson, K. D.; Rogers, L. T.

    1991-11-01

    This document is a continuation and expansion of an earlier study that examines the feasibility of using the evaporation duct to support an alternative high-speed communication system for Navy applications. This Evaporation Duct Communication (EDCOM) experiment is a unique opportunity to evaluate another communication channel that can alleviate Navy ship-to-ship communication problems. Therefore, it is strongly recommended to proceed with this measurement program.

  1. Long time black hole evaporation with bounded Hawking flux

    NASA Astrophysics Data System (ADS)

    Grumiller, D.

    2004-05-01

    The long time behaviour of an evaporating black hole presents a challenge to theoretical physics and touches relevant conceptual issues of quantum gravity, such as the information paradox. There are basically two strategies: top-down, i.e., constructing first a full quantum theory of gravity and discussing black hole evaporation as a particular application thereof, and bottom-up, i.e., sidestepping the difficulties inherent to the former approach by invoking `reasonable' ad hoc assumptions. Exploiting the fact that the Schwarzschild black hole can be described by means of an effective theory in 2D, a particular dilaton gravity model, the latter route is pursued. A crucial technical ingredient is Izawa's result on consistent deformations of 2D BF theory, while the most relevant physical assumption is boundedness of the asymptotic matter flux during the whole evaporation process. Together with making technical assumptions which can be relaxed, the dynamics of the evaporating black hole is described by means of consistent deformations of the underlying gauge symmetries with only one important deformation parameter. An attractor solution, the end-point of the evaporation process, is found. Its metric is flat. However, the behaviour of the dilaton field (which corresponds to the surface area) is non-trivial: it is argued that during the final flicker a first-order phase transition occurs from a linear to a constant dilaton vacuum. Consequently, a shock wave is emitted as a final `thunderbolt' with a total energy of a fraction of the Planck mass. Relations to ultrarelativistic boosts are pointed out. Another fraction of the Planck mass may reside in a cold remnant. The physical discussion addresses the lifetime, the specific heat, the Carter Penrose diagram, the information paradox and cosmological implications. The phenomenon of `dilaton evaporation' to a constant dilaton vacuum might be of relevance also for higher dimensional scalar tensor theories. Based on an

  2. Sheet Membrane Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Trevino, Luis; Zapata, Felipe; Dillion, Paul; Castillo, Juan; Vonau, Walter; Wilkes, Robert; Vogel, Matthew; Frodge, Curtis

    2013-01-01

    A document describes a sheet membrane spacesuit water membrane evaporator (SWME), which allows for the use of one common water tank that can supply cooling water to the astronaut and to the evaporator. Test data showed that heat rejection performance dropped only 6 percent after being subjected to highly contaminated water. It also exhibited robustness with respect to freezing and Martian atmospheric simulation testing. Water was allowed to freeze in the water channels during testing that simulated a water loop failure and vapor backpressure valve failure. Upon closing the backpressure valve and energizing the pump, the ice eventually thawed and water began to flow with no apparent damage to the sheet membrane. The membrane evaporator also serves to de-gas the water loop from entrained gases, thereby eliminating the need for special degassing equipment such as is needed by the current spacesuit system. As water flows through the three annular water channels, water evaporates with the vapor flowing across the hydrophobic, porous sheet membrane to the vacuum side of the membrane. The rate at which water evaporates, and therefore, the rate at which the flowing water is cooled, is a function of the difference between the water saturation pressure on the water side of the membrane, and the pressure on the vacuum side of the membrane. The primary theory is that the hydrophobic sheet membrane retains water, but permits vapor pass-through when the vapor side pressure is less than the water saturation pressure. This results in evaporative cooling of the remaining water.

  3. Evaporation mitigation by floating modular devices

    NASA Astrophysics Data System (ADS)

    Hassan, M. M.; Peirson, W. L.

    2016-05-01

    Prolonged periods of drought and consequent evaporation from open water bodies in arid parts of Australia continue to be a threat to water availability for agricultural production. Over many parts of Australia, the annual average evaporation exceeds the annual precipitation by more than 5 times. Given its significance, it is surprising that no evaporation mitigation technique has gained widespread adoption to date. High capital and maintenance costs of manufactured products are a significant barrier to implementation. The use of directly recycled clean plastic containers as floating modular devices to mitigate evaporation has been investigated for the first time. A six-month trial at an arid zone site in Australia of this potential cost effective solution has been undertaken. The experiment was performed using clean conventional drinking water bottles as floating modules on the open water surface of 240-L tanks with three varying degrees of covering (nil, 34% and 68%). A systematic reduction in evaporation is demonstrated during the whole study period that is approximately linearly proportional to the covered surface. These results provide a potential foundation for robust evaporation mitigation with the prospect of implementing a cost-optimal design.

  4. Water repellency diminishes peatland evaporation after wildfire

    NASA Astrophysics Data System (ADS)

    Kettridge, Nick; Lukenbach, Max; Hokanson, Kelly; Devito, Kevin; Hopkinson, Chris; Petrone, Rich; Mendoza, Carl; Waddington, Mike

    2016-04-01

    Peatlands are a critically important global carbon reserve. There is increasing concern that such ecosystems are vulnerable to projected increases in wildfire severity under a changing climate. Severe fires may exceed peatland ecological resilience resulting in the long term degradation of this carbon store. Evaporation provides the primary mechanisms of water loss from such environments and can regulate the ecological stress in the initial years after wildfire. We examine variations in evaporation within burned peatlands after wildfire through small scale chamber and large scale remote sensing measurements. We show that near-surface water repellency limits peatland evaporation in these initial years post fire. Water repellent peat produced by the fire restricts the supply of water to the surface, reducing evaporation and providing a strong negative feedback to disturbance. This previously unidentified feedback operates at the landscape scale. High surface temperatures that result from large reductions in evaporation within water repellent peat are observed across the 60,000 ha burn scar three months after the wildfire. This promotes high water table positions at a landscape scale which limit the rate of peat decomposition and supports the post fire ecohydrological recovery of the peatlands. However, severe burns are shown to exceed this negative feedback response. Deep burns at the peatland margins remove the hydrophobic layer, increasing post fire evaporation and leaving the peatland vulnerable to drying and associated ecological shifts.

  5. Evaporation-induced cavitation in nanofluidic channels

    PubMed Central

    Duan, Chuanhua; Karnik, Rohit; Lu, Ming-Chang; Majumdar, Arun

    2012-01-01

    Cavitation, known as the formation of vapor bubbles when liquids are under tension, is of great interest both in condensed matter science as well as in diverse applications such as botany, hydraulic engineering, and medicine. Although widely studied in bulk and microscale-confined liquids, cavitation in the nanoscale is generally believed to be energetically unfavorable and has never been experimentally demonstrated. Here we report evaporation-induced cavitation in water-filled hydrophilic nanochannels under enormous negative pressures up to -7 MPa. As opposed to receding menisci observed in microchannel evaporation, the menisci in nanochannels are pinned at the entrance while vapor bubbles form and expand inside. Evaporation in the channels is found to be aided by advective liquid transport, which leads to an evaporation rate that is an order of magnitude higher than that governed by Fickian vapor diffusion in macro- and microscale evaporation. The vapor bubbles also exhibit unusual motion as well as translational stability and symmetry, which occur because of a balance between two competing mass fluxes driven by thermocapillarity and evaporation. Our studies expand our understanding of cavitation and provide new insights for phase-change phenomena at the nanoscale. PMID:22343530

  6. TANK 32 EVAPORATOR FEED PUMP TRANSFER ANALYSIS

    SciTech Connect

    Tamburello, D; Richard Dimenna, R; Si Lee, S

    2009-01-27

    The transfer of liquid salt solution from Tank 32 to an evaporator is to be accomplished by activating the evaporator feed pump, with the supernate surface at a minimum height of approximately 74.4 inches above the sludge layer, while simultaneously turning on the downcomer with a flow rate of 110 gpm. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics (CFD) methods to determine the amount of entrained sludge solids pumped out of the tank toward the evaporator with the downcomer turned on. The analysis results shows that, for the minimum tank liquid level of 105 inches above the tank bottom (which corresponds to a liquid depth of 74.4 inches above the sludge layer), the evaporator feed pump will contain less than 0.1 wt% sludge solids in the discharge stream, which is an order of magnitude less than the 1.0 wt% undissolved solids (UDS) loading criteria to feed the evaporator. Lower liquid levels with respect to the sludge layer will result in higher amounts of sludge entrainment due to the increased plunging jet velocity from the downcomer disturbing the sludge layer.

  7. TANK 26 EVAPORATOR FEED PUMP TRANSFER ANALYSIS

    SciTech Connect

    Tamburello, D; Si Lee, S; Richard Dimenna, R

    2008-09-30

    The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics methods to determine the amount of entrained sludge solids pumped out of the tank to the evaporator with the downcomer turned on. The analysis results showed that, for the maximum and minimum supernate levels in Tank 26 (252.5 and 72 inches above the sludge layer, respectively), the evaporator feed pump will entrain between 0.05 and 0.1 wt% sludge solids weight fraction into the eductor, respectively. Lower tank liquid levels, with respect to the sludge layer, result in higher amounts of sludge entrainment due to the increased velocity of the plunging jets from the downcomer and evaporator feed pump bypass as well as decreased dissipation depth.

  8. Evaporation of carbon atoms from the open surface of silicon carbide and through graphene cells: Semiempirical quantum-chemical modeling

    NASA Astrophysics Data System (ADS)

    Alekseev, N. I.; Luchinin, V. V.; Charykov, N. A.

    2013-11-01

    The evaporation of silicon atoms during the epitaxial growth of graphene on the singular carbon and silicon faces of silicon carbide SiC was modeled by the semiempirical AM1 and PM3 methods. The analysis was performed for evaporation of atoms both from the open surface of SiC and through the surface of the formed graphene monolayers. The total activation barrier of the evaporation of the silicon atoms, their passage from the graphene cell, and further evaporation from graphene was shown to be lower than the barrier to evaporation of the silicon atom on a free surface of SiC. Passage through graphene is thus not the limiting stage of the process, but contributes significantly to the effective evaporation time.

  9. Separation of boric acid from PWR waste by volatilization during evaporation

    SciTech Connect

    Bruggeman, A.; Braet, J.; Smaers, F.; De Regge, P.

    1997-01-01

    SCK{circ}CEN has developed a process to separate boric acid during and/or after evaporation of the liquid waste from pressurized light-water reactors. The key goal is to achieve higher waste volume reduction factors, while maintaining low activity discharge limits. An additional goal is to obtain purified boric acid for recycling. The process is based on the volatility of boric acid in steam. The liquid waste is treated in a semicontinuous evaporator, which operates preferentially at a higher temperature than the present evaporators. The stream loaded with boric acid is fed to a column for fractional condensation with partial reflux. In this way, one obtains a highly concentrated waste that contains all the radioactive and chemical impurities and little boron, a concentrated boric acid solution which can be reused, as well as a highly decontaminated effluent without boron. In case replacement or adaptation of existing evaporators is less practical, one can adapt the process for the treatment of evaporator concentrates. After having been intensively tested at SCK{circ}CEN, the process has recently been demonstrated in a small pilot installation and with realistic liquid waste, at the nuclear power station in Doel, Belgium. The results corresponded to the theoretical predictions. After a transitional period, the boron concentration in the evaporator no longer increased and consequently did not limit the achievable waste volume reduction factor. The boric acid was recovered from the steam and during a supplementary treatment additional boric acid from the waste concentrate was recovered.

  10. Evaporation of LOX under supercritical and subcritical conditions

    NASA Technical Reports Server (NTRS)

    Yang, A. S.; Hsieh, W. H.; Kuo, K. K.; Brown, J. J.

    1993-01-01

    The evaporation of LOX under supercritical and subcritical conditions was studied experimentally and theoretically. In experiments, the evaporation rate and surface temperature were measured for LOX strand vaporizing in helium environments at pressures ranging from 5 to 68 atmospheres. Gas sampling and chromatography analysis were also employed to profile the gas composition above the LOX surface for the purpose of model validation. A comprehensive theoretical model was formulated and solved numerically to simulate the evaporation process of LOX at high pressures. The model was based on the conservation equations of mass, momentum, energy, and species concentrations for a multicomponent system, with consideration of gravitational body force, solubility of ambient gases in liquid, and variable thermophysical properties. Good agreement between predictions and measured oxygen mole fraction profiles was obtained. The effect of pressure on the distribution of the Lewis number, as well as the effect of variable diffusion coefficient, were further examined to elucidate the high-pressure transport behavior exhibited in the LOX vaporization process.

  11. Magnetron deposition of coatings with evaporation of the target

    NASA Astrophysics Data System (ADS)

    Bleykher, G. A.; Krivobokov, V. P.; Yuryeva, A. V.

    2015-12-01

    We analyze the potentialities of the plasma in various types of magnetron sputtering systems including pulsed and liquid-target systems for producing intense emission of atoms and high-rate deposition of coatings. For this purpose, a mathematical model of thermal and erosion processes in the target is developed based on the heat conduction equations taking into account first-order phase transitions. Using this model, we determine the parameters of magnetrons for which intense evaporation of atoms from the target surface takes place. It is shown that evaporation leads to an increase in the growth rate of metal coatings by 1-2 orders of magnitude as compared to conventional magnetron systems based only on collisional sputtering.

  12. Flow visualization and characterization of evaporating liquid drops

    NASA Technical Reports Server (NTRS)

    Chao, David F. (Inventor); Zhang, Nengli (Inventor)

    2004-01-01

    An optical system, consisting of drop-reflection image, reflection-refracted shadowgraphy and top-view photography, is used to measure the spreading and instant dynamic contact angle of a volatile-liquid drop on a non-transparent substrate. The drop-reflection image and the shadowgraphy is shown by projecting the images of a collimated laser beam partially reflected by the drop and partially passing through the drop onto a screen while the top view photograph is separately viewed by use of a camera video recorder and monitor. For a transparent liquid on a reflective solid surface, thermocapillary convection in the drop, induced by evaporation, can be viewed nonintrusively, and the drop real-time profile data are synchronously recorded by video recording systems. Experimental results obtained from this technique clearly reveal that evaporation and thermocapillary convection greatly affect the spreading process and the characteristics of dynamic contact angle of the drop.

  13. Experimental and theoretical investigations of falling film evaporation

    NASA Astrophysics Data System (ADS)

    Pehlivan, Hüseyin; Özdemir, Mustafa

    2012-06-01

    In this study, a mathematical model was developed for falling film evaporation in vacuum using heat transfer relations. An experimental device was designed. experimental set-up which was used was equipped with a triangular weir distribution device and it had the ability to record data up to 3 m. Experiments were performed in a single-effect process with sucrose-water solution varying from 3 to 20% concentration rate of sucrose and we used a vertical tube evaporator with the dimensions of laboratory scale. The model that was developed considers convection, shear stress, viscosity and conjugate heat transfer while most of the previous works ignored these factors. The main factors influencing the heat transfer mechanism performance of the unit were investigated and analyzed. We concluded that the experimental studies are verified by the developed model. Furthermore, it was also concluded that, the heat transfer is affected by the mass flow rate, sucrose concentration rate in solution, film thickness and pressure.

  14. Solid material evaporation into an ECR source by laser ablation

    SciTech Connect

    Harkewicz, R.; Stacy, J.; Greene, J.; Pardo, R.C.

    1993-09-01

    In an effort to explore new methods of producing ion beams from solid materials, we are attempting to develop a laser-ablation technique for evaporating materials directly into an ECR ion source plasma. A pulsed NdYaG laser with approximately 25 watts average power and peak power density on the order of 10{sup 7} W/cm{sup 2} has been used off-line to measure ablation rates of various materials as a function of peak laser power. The benefits anticipated from the successful demonstration of this technique include the ability to use very small quantities of materials efficiently, improved material efficiency of incorporation into the ECR plasma, and decoupling of the material evaporation process from the ECR source tuning operation. Here we report on the results of these tests and describe the design for incorporating such a system directly with the ATLAS PII-ECR ion source.

  15. Evaporation and condensation at a liquid surface. I. Argon

    NASA Astrophysics Data System (ADS)

    Yasuoka, Kenji; Matsumoto, Mitsuhiro; Kataoka, Yosuke

    1994-11-01

    Molecular dynamics computer simulations were carried out to investigate the dynamics of evaporation and condensation for argon at the temperature of 80 and 100 K. From the decrease of the survival probability of vapor molecules, the ratio of self reflection to collision is estimated to be 12%-15%, only weakly dependent on the temperature. This suggests that argon vapor molecules are in the condition of almost complete capture, and the condensation is considered to be a barrierless process. The total ratio of reflection which is evaluated with the flux correlation of condensation and evaporation is 20% at both temperature. The difference between these two ratios of reflection is ascribed to a phenomenon that vapor molecules colliding with the surface drive out other liquid molecules. This molecule exchange at the surface is as important as the self-reflection, and the conventional picture of condensation as a unimolecular chemical reaction is not appropriate.

  16. Evaporation Loss of Light Elements as a Function of Cooling Rate: Logarithmic Law

    NASA Technical Reports Server (NTRS)

    Xiong, Yong-Liang; Hewins, Roger H.

    2003-01-01

    Knowledge about the evaporation loss of light elements is important to our understanding of chondrule formation processes. The evaporative loss of light elements (such as B and Li) as a function of cooling rate is of special interest because recent investigations of the distribution of Li, Be and B in meteoritic chondrules have revealed that Li varies by 25 times, and B and Be varies by about 10 times. Therefore, if we can extrapolate and interpolate with confidence the evaporation loss of B and Li (and other light elements such as K, Na) at a wide range of cooling rates of interest based upon limited experimental data, we would be able to assess the full range of scenarios relating to chondrule formation processes. Here, we propose that evaporation loss of light elements as a function of cooling rate should obey the logarithmic law.

  17. Evolution of tip shape during field evaporation of complex multilayer structures.

    PubMed

    Marquis, E A; Geiser, B P; Prosa, T J; Larson, D J

    2011-03-01

    Atom-probe tomography analysis of complex multilayer structures is a promising avenue for studying interfacial properties. However, significant artefacts in the three-dimensional reconstructed data arise due to the field evaporation process. To clarify the origin and impact of these artefacts for a FeCoB/FeCo/MgO/FeCo/IrMn multilayer, tip shapes were observed by transmission electron microscopy and compared to those obtained by finite difference modelling of electric fields and evaporation processes. It was found that the emitter shape is not spherical and its surface morphology evolves during successive evaporation of the different layers. This evolving morphology contributes to the artefacts generally observed in the reconstructed atom-probe data for multilayer structures because algorithms for three-dimensional reconstruction are based on the assumption that the shape of the emitter during field evaporation is spherical. Some proposed improvements to data reconstruction are proposed. PMID:21118216

  18. A Comparison of Measured Evaporation at Wet and Mesic Sites to Modeled Evaporation Using BIOME BGC in the Arctic Coastal Plain

    NASA Astrophysics Data System (ADS)

    Engstrom, R. N.; Hope, A. S.; Harazano, Y.; Kwon, H.; Mano, M.

    2004-05-01

    The growing season evaporation process in Arctic ecosystems is affected by the unique characteristics of the region, including non-vascular vegetation, a substantial ground heat sink, low energy inputs, and other factors. These characteristics may be a source of uncertainty in evaporation estimates using models developed for mid-latitude ecosystems. By incorporating these characteristics into evaporation models, the accuracy of model predictions should improve. In this study the ecophysiological model BIOME BGC was adapted to Arctic environments by including a non-vascular vegetation evaporation routine, adding ground heat flux as an input, accounting for ground shading by dead vegetation, developing a new parameter set for tundra vegetation, and by accounting for ponded water evaporation. The purpose of this study was to test the ability of this modified version of BIOME BGC to simulate measured evaporation fluxes at two eddy flux tower locations with contrasting wetness conditions in Arctic coastal plain ecosystems. Model simulations were compared to measured evaporation at two eddy flux towers located within 1 km of each other in Barrow, Alaska with substantially different moisture regimes for the 1999, 2000, and 2001 summer seasons. One tower was located in a marsh area that has standing water while the other tower is located in a drier, mesic tundra location. Results indicated that the model performed well at the wet site however, it tended to over predict evaporation at the drier site. This over prediction is most likely due to the affects of lateral redistribution of water from the drier site not being accounted for in model simulations. Additional results indicated that the modified BIOME BGC model was able to simulate measured leaf area index and inter-annual variations in snowmelt date well.

  19. The WACMOS-ET project - Part 2: Evaluation of global terrestrial evaporation data sets

    NASA Astrophysics Data System (ADS)

    Miralles, D. G.; Jiménez, C.; Jung, M.; Michel, D.; Ershadi, A.; McCabe, M. F.; Hirschi, M.; Martens, B.; Dolman, A. J.; Fisher, J. B.; Mu, Q.; Seneviratne, S. I.; Wood, E. F.; Fernández-Prieto, D.

    2016-02-01

    The WAter Cycle Multi-mission Observation Strategy - EvapoTranspiration (WACMOS-ET) project aims to advance the development of land evaporation estimates on global and regional scales. Its main objective is the derivation, validation, and intercomparison of a group of existing evaporation retrieval algorithms driven by a common forcing data set. Three commonly used process-based evaporation methodologies are evaluated: the Penman-Monteith algorithm behind the official Moderate Resolution Imaging Spectroradiometer (MODIS) evaporation product (PM-MOD), the Global Land Evaporation Amsterdam Model (GLEAM), and the Priestley-Taylor Jet Propulsion Laboratory model (PT-JPL). The resulting global spatiotemporal variability of evaporation, the closure of regional water budgets, and the discrete estimation of land evaporation components or sources (i.e. transpiration, interception loss, and direct soil evaporation) are investigated using river discharge data, independent global evaporation data sets and results from previous studies. In a companion article (Part 1), Michel et al. (2016) inspect the performance of these three models at local scales using measurements from eddy-covariance towers and include in the assessment the Surface Energy Balance System (SEBS) model. In agreement with Part 1, our results indicate that the Priestley and Taylor products (PT-JPL and GLEAM) perform best overall for most ecosystems and climate regimes. While all three evaporation products adequately represent the expected average geographical patterns and seasonality, there is a tendency in PM-MOD to underestimate the flux in the tropics and subtropics. Overall, results from GLEAM and PT-JPL appear more realistic when compared to surface water balances from 837 globally distributed catchments and to separate evaporation estimates from ERA-Interim and the model tree ensemble (MTE). Nonetheless, all products show large dissimilarities during conditions of water stress and drought and

  20. Solitons as the Early Stage of Quasicondensate Formation during Evaporative Cooling

    SciTech Connect

    Witkowska, E.; Deuar, P.; Gajda, M.; RzaPzewski, K.

    2011-04-01

    We calculate the evaporative cooling dynamics of trapped one-dimensional Bose-Einstein condensates for parameters leading to a range of condensates and quasicondensates in the final equilibrium state, using the classical fields method. We confirm that solitons are created during the evaporation process by the Kibble-Zurek mechanism, but subsequently dissipate during thermalization. However, their signature remains in the phase coherence length, which is approximately conserved during dissipation in this system.

  1. A comparison of evaporation duct models for IREPS (Integrated Refractive Effects Prediction System)

    NASA Astrophysics Data System (ADS)

    Patterson, W.

    1984-06-01

    An evaluation of current meteorological measurement techniques to determine adequate description of the surface meteorological processes used to infer evaporation duct height includes a comparison of relative performance, sensitivities to meteorological inputs, and ease of computation for several standard evaporation duct height models. EM wave propagation pathloss models are compared and evaluated, and a maximum range of detection error is determined for the modified NOSC propagation model employed by the Integrated Refractive Effects Prediction System (IREPS).

  2. Physical drivers of lake evaporation across a gradient of climate and lake types

    NASA Astrophysics Data System (ADS)

    Lenters, J. D.; Blanken, P.; Healey, N. C.; Hinkel, K. M.; Ong, J.; Peake, C.; Potter, B. L.; Riveros-Iregui, D. A.; Spence, C.; Van Cleave, K.; Zlotnik, V. A.

    2014-12-01

    Inland waters exchange sensible and latent heat with the overlying atmosphere in ways that are very different from the surrounding terrestrial landscape. Depending on the regional climate and lake characteristics, open-water evaporation from lakes can vary out of phase with terrestrial evapotranspiration within the watershed, and key atmospheric drivers are often different as well. Lake evaporation is a complex process that interacts with many aspects of a lake ecosystem, including water temperature, vertical mixing, lake chemistry, stratification, ice cover, and water levels. Although driven primarily by vapor pressure gradient and wind speed, evaporation is also an energy-consuming process. This leads not only to significant roles from net radiation, sensible heat flux, and other components of the surface energy budget, but it also results in important feedbacks on lake temperature, ice cover, and other evaporation-mediating processes. As such, defining the climatic variables that "drive" lake evaporation is far from straightforward and often depends on timescale, lake depth, and characteristics of the regional climate. In this study, we provide some insight into the problem by examining the energy budget of a variety of lakes across a range of climatic gradients and lake types. This includes shallow Arctic lakes, deep temperate lakes, and a hypersaline lake in a semi-arid climate. Our results reveal a wide range of evaporative response to climatic forcing, including some lakes that show counterintuitive effects or even opposite responses to those of other lakes. Although process-based, mechanistic models should be able to account for such complexities, these findings highlight the need for caution when interpreting climatic drivers of lake evaporation. It is not likely, for example, that models of a solely empirical or statistical nature would be sufficient to fully capture the physics and dynamics of evaporation, particularly in an ever-changing climate.

  3. Evaporation of liquids from cylindrical vessels under conditions of free concentrational convection in a gas phase

    SciTech Connect

    Izmailov, Yu.G.; Pisarev, N.M.; Vyatkin, G.P.

    1995-12-01

    An analytical solution is obtained for the axisymmetric problem of free concentrational convection in a vapor-gas mixture with isothermal evaporation of liquids from open cylindrical vessels. Formulas are derived to calculate concentration fields, local and integral mass fluxes of vapor. A comparative analysis of the results of analytical and numerical simulation is carried out for the processes of the evaporation of liquids under the conditions of convective mass transfer.

  4. Thermocapillary instabilities in an evaporating drop deposited onto a heated substrate

    NASA Astrophysics Data System (ADS)

    Sobac, B.; Brutin, D.

    2012-03-01

    The present study is an experimental investigation regarding the evaporation of ethanol drops deposited onto a heated substrate in a partial wetting situation. The originality of this work is based on the simultaneous observation of the kinetics of evaporation, heat and mass transfers, the triple-line dynamic, and thermal motions inside the drop. The triple line recedes during the drop evaporation and a spontaneous development of thermal-convective instabilities driven by the evaporation are observed. These instabilities are interpreted as hydrothermal waves induced by surface tension gradient along the free surface. An infrared technique is used to investigate the temporal and spatial dynamics of the hydrothermal waves. Results reveal a non-linear evolution of the number of waves as well as several instability regimes. A complete description of the drop evaporation with the evidence of several phases is provided. The influence of geometrical and thermal parameters has been analyzed and raised scaling laws on hydrodynamic and energy transport. The drop evaporation appears to be characterized by a constant drop Nusselt number of a value 1.7 during all the process which highlights both the importance of conduction and convection in the energy transport in an evaporating drop.

  5. Evaporation of sessile droplets affected by graphite nanoparticles and binary base fluids.

    PubMed

    Zhong, Xin; Duan, Fei

    2014-11-26

    The effects of ethanol component and nanoparticle concentration on evaporation dynamics of graphite-water nanofluid droplets have been studied experimentally. The results show that the formed deposition patterns vary greatly with an increase in ethanol concentration from 0 to 50 vol %. Nanoparticles have been observed to be carried to the droplet surface and form a large piece of aggregate. The volume evaporation rate on average increases as the ethanol concentration increases from 0 to 50 vol % in the binary mixture nanofluid droplets. The evaporation rate at the initial stage is more rapid than that at the late stage to dry, revealing a deviation from a linear fitting line, standing for a constant evaporation rate. The deviation is more intense with a higher ethanol concentration. The ethanol-induced smaller liquid-vapor surface tension leads to higher wettability of the nanofluid droplets. The graphite nanoparticles in ethanol-water droplets reinforce the pinning effect in the drying process, and the droplets with more ethanol demonstrate the depinning behavior only at the late stage. The addition of graphite nanoparticles in water enhances a droplet baseline spreading at the beginning of evaporation, a pinning effect during evaporation, and the evaporation rate. However, with a relatively high nanoparticle concentration, the enhancement is attenuated. PMID:25372453

  6. Nanoparticle agglomeration in an evaporating levitated droplet for different acoustic amplitudes

    NASA Astrophysics Data System (ADS)

    Tijerino, Erick; Basu, Saptarshi; Kumar, Ranganathan

    2013-01-01

    Radiatively heated levitated functional droplets with nanosilica suspensions exhibit three distinct stages namely pure evaporation, agglomeration, and finally structure formation. The temporal history of the droplet surface temperature shows two inflection points. One inflection point corresponds to a local maximum and demarcates the end of transient heating of the droplet and domination of vaporization. The second inflection point is a local minimum and indicates slowing down of the evaporation rate due to surface accumulation of nanoparticles. Morphology and final precipitation structures of levitated droplets are due to competing mechanisms of particle agglomeration, evaporation, and shape deformation. In this work, we provide a detailed analysis for each process and propose two important timescales for evaporation and agglomeration that determine the final diameter of the structure formed. It is seen that both agglomeration and evaporation timescales are similar functions of acoustic amplitude (sound pressure level), droplet size, viscosity, and density. However, we show that while the agglomeration timescale decreases with initial particle concentration, the evaporation timescale shows the opposite trend. The final normalized diameter can be shown to be dependent solely on the ratio of agglomeration to evaporation timescales for all concentrations and acoustic amplitudes. The structures also exhibit various aspect ratios (bowls, rings, spheroids) which depend on the ratio of the deformation timescale (tdef) and the agglomeration timescale (tg). For tdef

  7. Surfactant-Enhanced Benard Convection on an Evaporating Drop

    NASA Astrophysics Data System (ADS)

    Nguyen, Van X.; Stebe, Kathleen J.

    2001-11-01

    Surfactant effects on an evaporating drop are studied experimentally. Using a fluorescent probe, the distribution and surface phase of the surfactant is directly imaged throughout the evaporation process. From these experiments, we identify conditions in which surfactants promote surface tension-driven Benard instabilities in aqueous systems. The drops under study contain finely divided particles, which act as tracers in the flow, and form well-defined patterns after the drop evaporates. Two flow fields have been reported in this system. The first occurs because the contact line becomes pinned by solid particles at the contact line region. In order for the contact line to remain fixed, an outward flow toward the ring results, driving further accumulation at the contact ring. A ‘coffee ring’ of particles is left as residue after the drop evaporates[1]. The second flow is Benard convection, driven by surface tension gradients on the drop[2,3]. In our experiments, an insoluble monolayer of pentadecanoic acid is spread at the interface of a pendant drop. The surface tension is recorded, and the drop is deposited on a well-defined solid substrate. Fluorescent images of the surface phase of the surfactant are recorded as the drop evaporates. The surfactant monolayer assumes a variety of surface states as a function of the area per molecule at the interface: surface gaseous, surface liquid expanded, and surface liquid condensed phases[4]. Depending upon the surface state of the surfactant as the drop evaporates, transitions of residue patterns left by the particles occur, from the coffee ring pattern to Benard cells to irregular patterns, suggesting a strong resistance to outward flow are observed. The occurrence of Benard cells on a surfactant-rich interface occurs when the interface is in LE-LC coexistence. Prior research concerning surfactant effects on this instability predict that surfactants are strongly stabilizing[5]. The mechanisms for this change in behavior

  8. LITERATURE REVIEW ON IMPACT OF GLYCOLATE ON THE 2H EVAPORATOR AND THE EFFLUENT TREATMENT FACILITY

    SciTech Connect

    Adu-Wusu, K.

    2012-05-10

    Glycolic acid (GA) is being studied as an alternate reductant in the Defense Waste Processing Facility (DWPF) feed preparation process. It will either be a total or partial replacement for the formic acid that is currently used. A literature review has been conducted on the impact of glycolate on two post-DWPF downstream systems - the 2H Evaporator system and the Effluent Treatment Facility (ETF). The DWPF recycle stream serves as a portion of the feed to the 2H Evaporator. Glycolate enters the evaporator system from the glycolate in the recycle stream. The overhead (i.e., condensed phase) from the 2H Evaporator serves as a portion of the feed to the ETF. The literature search revealed that virtually no impact is anticipated for the 2H Evaporator. Glycolate may help reduce scale formation in the evaporator due to its high complexing ability. The drawback of the solubilizing ability is the potential impact on the criticality analysis of the 2H Evaporator system. It is recommended that at least a theoretical evaluation to confirm the finding that no self-propagating violent reactions with nitrate/nitrites will occur should be performed. Similarly, identification of sources of ignition relevant to glycolate and/or update of the composite flammability analysis to reflect the effects from the glycolate additions for the 2H Evaporator system are in order. An evaluation of the 2H Evaporator criticality analysis is also needed. A determination of the amount or fraction of the glycolate in the evaporator overhead is critical to more accurately assess its impact on the ETF. Hence, use of predictive models like OLI Environmental Simulation Package Software (OLI/ESP) and/or testing are recommended for the determination of the glycolate concentration in the overhead. The impact on the ETF depends on the concentration of glycolate in the ETF feed. The impact is classified as minor for feed glycolate concentrations {le} 33 mg/L or 0.44 mM. The ETF unit operations that will have

  9. Kepler Planets: A Tale of Evaporation

    NASA Astrophysics Data System (ADS)

    Owen, James E.; Wu, Yanqin

    2013-10-01

    Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ~0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R ⊕. Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ~0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M ⊕ and the

  10. KEPLER PLANETS: A TALE OF EVAPORATION

    SciTech Connect

    Owen, James E.; Wu, Yanqin E-mail: wu@astro.utoronto.ca

    2013-10-01

    Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ∼0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R{sub ⊕}. Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ∼0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M

  11. Evaporation and reference evapotranspiration trends in Spain

    NASA Astrophysics Data System (ADS)

    Sanchez-Lorenzo, Arturo; Vicente-Serrano, Sergio M.; Wild, Martin; Azorin-Molina, Cesar; Calbó, Josep; Revuelto, Jesús; López-Moreno, Juan I.; Moran-Tejeda, Enrique; Martín-Hernández, Natalia; Peñuelas, Josep

    2015-04-01

    Interest is growing in the trends of atmospheric evaporation demand, increasing the need for long-term time series. In this study, we first describe the development of a dataset on evaporation in Spain based on long-term series of Piché and pan measurement records. Piché measurements have been reported for >50 stations since the 1960s. Measurements of pan evaporation, which is a much more widely studied variable in the literature, are also available, but only since 1984 for 21 stations. Particular emphasis was placed on the homogenization of this dataset (for more details, we refer to Sanchez-Lorenzo et al., 2014, Clim Res, 61: 269-280). Both the mean annual Piché and pan series over Spain showed evaporative increases during the common study period (1985-2011). Furthermore, using the annual Piché records since the 1960s, an evaporation decline was detected from the 1960s to the mid-1980s, which resulted in a non-significant trend over the entire 1961-2011 period. Our results indicate agreement between the decadal variability of reference evapotranspiration (Vicente-Serrano et al., 2014, Glob Planet Chang, 121: 26-40) and surface solar radiation (Sanchez-Lorenzo et al., 2013, Glob Planet Chang, 100: 343-352) and the evaporation from Piché and pan measurements since the mid-1980s, especially during summer. Nevertheless, this agreement needs attention, as Piché evaporimeters are inside meteorological screens and not directly exposed to radiation. Thus, as Piché readings are mainly affected by the aerodynamic term in Penman's evaporation equation and pan records are affected by both the heat balance and aerodynamic terms, the results suggest that both terms must be highly and positively correlated in Spain. In order to check this hypothesis, the radiative and aerodynamic components were estimated using the Penman's equation. The results show that the relationship with the radiative components is weaker than that with the aerodynamic component for both pan and

  12. Evaporation and land surface energy budget at the Salar de Atacama, Northern Chile

    NASA Astrophysics Data System (ADS)

    Kampf, Stephanie K.; Tyler, Scott W.; Ortiz, Cristián A.; Muñoz, José F.; Adkins, Paula L.

    2005-08-01

    Playa systems are driven by evaporation processes, yet the mechanisms by which evaporation occurs through playa salt crusts are still poorly understood. In this study we examine playa evaporation as it relates to land surface energy fluxes, salt crust characteristics, groundwater and climate at the Salar de Atacama, a 3000 km 2 playa in northern Chile containing a uniquely broad range of salt crust types. Land surface energy budget measurements were taken at eight representative sites on this playa during winter (August 2001) and summer (January 2002) seasons. Measured values of net all-wave radiation were highest at vegetated and rough halite crust sites and lowest over smooth, highly reflective salt crusts. Over most of the Salar de Atacama, net radiation was dissipated by means of soil and sensible heat fluxes. Dry salt crusts tended to heat and cool very quickly, whereas soil heating and cooling occurred more gradually at wetter vegetated sites. Sensible heating was strongly linked to wind patterns, with highest sensible heat fluxes occurring on summer days with strong afternoon winds. Very little energy available at the land surface was used to evaporate water. Eddy covariance measurements could only constrain evaporation rates to within 0.1 mm d -1, and some measured evaporation rates were less than this margin of uncertainty. Evaporation rates ranged from 0.1 to 1.1 mm d -1 in smooth salt crusts around the margin of the salar and from 0.4 to 2.8 mm d -1 in vegetated areas. No evaporation was detected from the rugged halite salt crust that covers the interior of the salar, though the depth to groundwater is less than 1 m in this area. These crusts therefore represent a previously unrecorded end member condition in which the salt crusts form a practically impermeable barrier to evaporation.

  13. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Hodgson, Ed; Izenso, Mike; Chan, Weibo; Cupples, Scott

    2011-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust non-venting system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's lithium chloride Heat Pump Radiator (HPR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. The SEAR is evacuated at the onset of operations and thereafter, the water vapor absorption rate of the HPR maintains a low pressure environment for the SWME to evaporate effectively. This water vapor captured by solid LiCl in the HPR with a high enthalpy of absorption, results in sufficient temperature lift to reject most of the heat to space by radiation. After the sortie, the HPR would be heated up in a regenerator to drive off and recover the absorbed evaporant. A one-fourth scale prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The HPR was able to stably reject 60 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  14. Gravity Effects in Condensing and Evaporating Films

    NASA Technical Reports Server (NTRS)

    Hermanson, J. C.; Som, S. M.; Allen, J. S.; Pedersen, P. C.

    2004-01-01

    A general overview of gravity effects in condensing and evaporating films is presented. The topics include: 1) Research Overview; 2) NASA Recognizes Critical Need for Condensation & Evaporation Research to Enable Human Exploration of Space; 3) Condensation and Evaporation Research in Reduced Gravity is Enabling for AHST Technology Needs; 4) Differing Role of Surface Tension on Condensing/Evaporating Film Stability; 5) Fluid Mechanisms in Condensing and Evaporating Films in Reduced Gravity; 6) Research Plan; 7) Experimental Configurations for Condensing Films; 8) Laboratory Condensation Test Cell; 9) Aircraft Experiment; 10) Condensation Study Current Test Conditions; 11) Diagnostics; 12) Shadowgraph Images of Condensing n- pentane Film in Unstable (-1g) Configuration; 13) Condensing n-Pentane Film in Normal Gravity (-1g) at Constant Pressure; 14) Condensing n-Pentane Film in Normal Gravity (-1g) with Cyclic Pressure; 15) Non-condensing Pumped Film in Normal Gravity (-1g); 16) Heat Transfer Coefficient in Developing, Unstable Condensing Film in Normal Gravity; 17) Heat Transfer for Unsteady Condensing Film (-1g); 18) Ultrasound Measurement of Film Thickness N-pentane Film, Stable (+1g) Configuration; and 19) Ultrasound Measurement of Film Thickness N-pentane Film, Unstable (-1g) Configuration.

  15. The characteristic of evaporative cooling magnet for ECRIS.

    PubMed

    Xiong, B; Ruan, L; Gu, G B; Lu, W; Zhang, X Z; Zhan, W L

    2016-02-01

    Compared with traditional de-ionized pressurized-water cooled magnet of ECRIS, evaporative cooling magnet has some special characteristics, such as high cooling efficiency, simple maintenance, and operation. The analysis is carried out according to the design and operation of LECR4 (Lanzhou Electron Cyclotron Resonance ion source No. 4, since July 2013), whose magnet is cooled by evaporative cooling technology. The insulation coolant replaces the de-ionized pressurized-water to absorb the heat of coils, and the physical and chemical properties of coolant remain stable for a long time with no need for purification or filtration. The coils of magnet are immersed in the liquid coolant. For the higher cooling efficiency of coolant, the current density of coils can be greatly improved. The heat transfer process executes under atmospheric pressure, and the temperature of coils is lower than 70 °C when the current density of coils is 12 A/mm(2). On the other hand, the heat transfer temperature of coolant is about 50 °C, and the heat can be transferred to fresh air which can save cost of water cooling system. Two years of LECR4 stable operation show that evaporative cooling technology can be used on magnet of ECRIS, and the application advantages are very obvious. PMID:26931937

  16. Evaporative cooling in a radio-frequency trap

    SciTech Connect

    Garrido Alzar, Carlos L.; Perrin, Helene; Lorent, Vincent; Garraway, Barry M.

    2006-11-15

    A theoretical investigation for implementing a scheme of forced evaporative cooling in radio-frequency (rf) adiabatic potentials is presented. Supposing the atoms to be trapped in a combination of a dc magnetic field and a rf field at frequency {omega}{sub 1}, the cooling procedure is facilitated using a second rf source at frequency {omega}{sub 2}. This second rf field produces a controlled coupling between the spin states dressed by {omega}{sub 1}. The evaporation is then possible in a pulsed or continuous mode. In the pulsed case, atoms with a given energy are transferred into untrapped dressed states by abruptly switching off the {omega}{sub 2} coupling. In the continuous case, it is possible for energetic atoms to adiabatically follow the doubly dressed states and escape out of the trap. Our results also show that when {omega}{sub 1} and {omega}{sub 2} are separated by at least the Rabi frequency associated with {omega}{sub 1}, additional evaporation zones appear which can make this process more efficient.

  17. Temperature distribution along the surface of evaporating droplets.

    PubMed

    Zhang, Kai; Ma, Liran; Xu, Xuefeng; Luo, Jianbin; Guo, Dan

    2014-03-01

    The surface temperature can significantly affect the flow field of drying droplets. Most previous studies assumed a monotonic temperature variation along the droplet surface. However, the present analyses indicate that a nonmonotonic spatial distribution of the surface temperature should occur. Three different patterns of the surface temperature distribution may appear during the evaporation process of liquid droplets: (i) the surface temperature increases monotonically from the center to the edge of the droplet; (ii) the surface temperature exhibits a nonmonotonic spatial distribution along the droplet surface; (iii) the surface temperature decreases monotonically from the center to the edge of the droplet. These surface temperature distributions can be explained by combining the evaporative cooling at the droplet surface and the heat conduction across the substrate and the liquid. Furthermore, a "phase diagram" for the distribution of the surface temperature is introduced and the effect of the spatial temperature distribution along the droplet surface on the flow structure of the droplet is discussed. The results may provide a better understanding of the Marangoni effect of drying droplets and provide a potential way to control evaporation-driven deposition as well as the assembly of colloids and other materials. PMID:24730849

  18. The characteristic of evaporative cooling magnet for ECRIS

    NASA Astrophysics Data System (ADS)

    Xiong, B.; Ruan, L.; Gu, G. B.; Lu, W.; Zhang, X. Z.; Zhan, W. L.

    2016-02-01

    Compared with traditional de-ionized pressurized-water cooled magnet of ECRIS, evaporative cooling magnet has some special characteristics, such as high cooling efficiency, simple maintenance, and operation. The analysis is carried out according to the design and operation of LECR4 (Lanzhou Electron Cyclotron Resonance ion source No. 4, since July 2013), whose magnet is cooled by evaporative cooling technology. The insulation coolant replaces the de-ionized pressurized-water to absorb the heat of coils, and the physical and chemical properties of coolant remain stable for a long time with no need for purification or filtration. The coils of magnet are immersed in the liquid coolant. For the higher cooling efficiency of coolant, the current density of coils can be greatly improved. The heat transfer process executes under atmospheric pressure, and the temperature of coils is lower than 70 °C when the current density of coils is 12 A/mm2. On the other hand, the heat transfer temperature of coolant is about 50 °C, and the heat can be transferred to fresh air which can save cost of water cooling system. Two years of LECR4 stable operation show that evaporative cooling technology can be used on magnet of ECRIS, and the application advantages are very obvious.

  19. Measurement of an Evaporating Drop on a Reflective Substrate

    NASA Technical Reports Server (NTRS)

    Chao, David F.; Zhang, Nengli

    2004-01-01

    A figure depicts an apparatus that simultaneously records magnified ordinary top-view video images and laser shadowgraph video images of a sessile drop on a flat, horizontal substrate that can be opaque or translucent and is at least partially specularly reflective. The diameter, contact angle, and rate of evaporation of the drop as functions of time can be calculated from the apparent diameters of the drop in sequences of the images acquired at known time intervals, and the shadowgrams that contain flow patterns indicative of thermocapillary convection (if any) within the drop. These time-dependent parameters and flow patterns are important for understanding the physical processes involved in the spreading and evaporation of drops. The apparatus includes a source of white light and a laser (both omitted from the figure), which are used to form the ordinary image and the shadowgram, respectively. Charge-coupled-device (CCD) camera 1 (with zoom) acquires the ordinary video images, while CCD camera 2 acquires the shadowgrams. With respect to the portion of laser light specularly reflected from the substrate, the drop acts as a plano-convex lens, focusing the laser beam to a shadowgram on the projection screen in front of CCD camera 2. The equations for calculating the diameter, contact angle, and rate of evaporation of the drop are readily derived on the basis of Snell s law of refraction and the geometry of the optics.

  20. Drying-Induced Evaporation of Secondary Organic Aerosol during Summer.

    PubMed

    El-Sayed, Marwa M H; Amenumey, Dziedzorm; Hennigan, Christopher J

    2016-04-01

    This study characterized the effect of drying on the concentration of atmospheric secondary organic aerosol (SOA). Simultaneous measurements of water-soluble organic carbon in the gas (WSOCg) and particle (WSOCp) phases were carried out in Baltimore, MD during the summertime. To investigate the effect of drying on SOA, the WSOCp measurement was alternated through an ambient channel (WSOCp) and a "dried" channel (WSOCp,dry) maintained at ∼35% relative humidity (RH). The average mass ratio between WSOCp,dry and WSOCp was 0.85, showing that significant evaporation of the organic aerosol occurred due to drying. The average amount of evaporated water-soluble organic matter (WSOM = WSOC × 1.95) was 0.6 μg m(-3); however, the maximum evaporated WSOM concentration exceeded 5 μg m(-3), demonstrating the importance of this phenomenon. The systematic difference between ambient and dry channels indicates a significant and persistent source of aqueous SOA formed through reversible uptake processes. The wide-ranging implications of the work are discussed, and include: new insight into atmospheric SOA formation; impacts on particle measurement techniques; a newly identified bias in PM2.5 measurements using the EPA's Federal Reference and Equivalent Methods (FRM and FEM); atmospheric model evaluations; and the challenge in relating ground-based measurements to remote sensing of aerosol properties. PMID:26910726

  1. Marangoni Convection and Deviations from Maxwells' Evaporation Model

    NASA Technical Reports Server (NTRS)

    Segre, P. N.; Snell, E. H.; Adamek, D. H.

    2003-01-01

    We investigate the convective dynamics of evaporating pools of volatile liquids using an ultra-sensitive thermal imaging camera. During evaporation, there are significant convective flows inside the liquid due to Marangoni forces. We find that Marangoni convection during evaporation can dramatically affect the evaporation rates of volatile liquids. A simple heat balance model connects the convective velocities and temperature gradients to the evaporation rates.

  2. Visualization of an evaporating thin layer during the evaporation of a nanofluid droplet.

    PubMed

    Shin, Dong Hwan; Allen, Jeffrey S; Choi, Chang Kyoung; Lee, Seong Hyuk

    2015-02-01

    During the evaporation of a droplet, there exists an evaporating thin layer that is difficult to visualize because of optical restrictions. The present study visualized this thin layer by using a reflective-mode, confocal microscope that can provide improved signal-to-noise focal plane imaging over traditional optical microscopy while simultaneously serving as an interferometer when imaging thin liquid films. The spatial distribution of the evaporating thin layer thickness was determined from interferometric fringe analysis. Three distinct fringe patterns, or regions, were observed depending on the nanoparticle concentration. These regions are referred to as uniform, slow extension, and rapid extension. The formation of the three regions is closely associated with the variation of the evaporating thin layer thickness of a nanofluid droplet. The nanoparticle bank formed near the contact line region substantially affects the rate of change in the evaporating thin layer thickness that increases with the nanoparticle concentration. PMID:25586137

  3. Chromospheric evaporation and decimetric radio emission in solar flares

    NASA Technical Reports Server (NTRS)

    Aschwanden, Markus J.; Benz, Arnold O.

    1995-01-01

    We have discovered decimetric signatures of the chromospheric evaporation process. Evidence for the radio detection of chromospheric evaporation is based on the radio-inferred values of (1) the electron density, (2) the propagation speed, and (3) the timing, which are found to be in good agreement with statistical values inferred from the blueshifted Ca XIX soft X-ray line. The physical basis of our model is that free-free absorption of plasma emission is strongly modified by the steep density gradient and the large temperature increase in the upflowing flare plasma. The steplike density increase at the chromospheric evaporation front causes a local discontinuity in the plasma frequency, manifested as almost infinite drift rate in decimetric type III bursts. The large temperature increase of the upflowing plasma considerably reduces the local free-free opacity (due to the T(exp -3/2) dependence) and thus enhances the brightness of radio bursts emitted at the local plasma frequency near the chromospheric evaporation front, while a high-frequency cutoff is expected in the high-density regions behind the front, which can be used to infer the velocity of the upflowing plasma. From model calculations we find strong evidence that decimetric bursts with a slowly drifting high-frequency cutoff are produced by fundamental plasma emission, contrary to the widespread belief that decimetric bursts are preferentially emitted at the harmonic plasma level. We analyze 21 flare episodes from 1991-1993 for which broadband (100-3000 MHz) radio dynamic spectra from Pheonix, hard X-ray data from (BATSE/CGRO) and soft X-ray data from Burst and Transient Source Experiment/Compton Gamma Ray Observatory (GOES) were available.

  4. Isotope mass fractionation during evaporation of Mg2SiO4

    NASA Technical Reports Server (NTRS)

    Davis, Andrew M.; Clayton, Robert N.; Mayeda, Toshiko K.; Hashimoto, Akihiko

    1990-01-01

    Synthetic forsterite (Mg2SiO4) was partially evaporated in vacuum for various durations and at different temperatures. The residual charges obtained when molten Mg2SiO4 was evaporated to 12 percent of its initial mass were enriched in heavy isotopes by about 20, 30, and 15 per mil/amu for O, Mg, and Si, respectively, whereas solid forsterite evaporated to a similar residual mass fraction showed negligible fractionations. These results imply that calcium and aluminum-rich refractory inclusions in carbonaceous chondrites must have been at least partially molten in the primordial solar nebula if the observed large mass fractionation effects were caused by evaporation processes in the nebula.

  5. Air Evaporation closed cycle water recovery technology - Advanced energy saving designs

    NASA Technical Reports Server (NTRS)

    Morasko, Gwyndolyn; Putnam, David F.; Bagdigian, Robert

    1986-01-01

    The Air Evaporation water recovery system is a visible candidate for Space Station application. A four-man Air Evaporation open cycle system has been successfully demonstrated for waste water recovery in manned chamber tests. The design improvements described in this paper greatly enhance the system operation and energy efficiency of the air evaporation process. A state-of-the-art wick feed design which results in reduced logistics requirements is presented. In addition, several design concepts that incorporate regenerative features to minimize the energy input to the system are discussed. These include a recuperative heat exchanger, a heat pump for energy transfer to the air heater, and solar collectors for evaporative heat. The addition of the energy recovery devices will result in an energy reduction of more than 80 percent over the systems used in earlier manned chamber tests.

  6. Evaporation and air-stripping to assess and reduce ethanolamines toxicity in oily wastewater.

    PubMed

    Libralato, G; Ghirardini, A Volpi; Avezzù, F

    2008-05-30

    Toxicity from industrial oily wastewater remains a problem even after conventional activated sludge treatment process, because of the persistence of some toxicant compounds. This work verified the removal efficiency of organic and inorganic pollutants and the effects of evaporation and air-stripping techniques on oily wastewater toxicity reduction. In a lab-scale plant, a vacuum evaporation procedure at three different temperatures and an air-stripping stage were tested on oily wastewater. Toxicity reduction/removal was observed at each treatment step via Microtox bioassay. A case study monitoring real scale evaporation was also done in a full-size wastewater treatment plant (WWTP). To implement part of a general project of toxicity reduction evaluation, additional investigations took into account the monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) role in toxicity definition after the evaporation phase, both as pure substances and mixtures. Only MEA and TEA appeared to contribute towards effluent toxicity. PMID:17980956

  7. An evaporation based digital microflow meter

    NASA Astrophysics Data System (ADS)

    Nie, C.; Frijns, A. J. H.; Mandamparambil, R.; Zevenbergen, M. A. G.; den Toonder, J. M. J.

    2015-11-01

    In this work, we present a digital microflow meter operating in the range 30-250 nl min-1 for water. The principle is based on determining the evaporation rate of the liquid via reading the number of wetted pore array structures in a microfluidic system, through which continuous evaporation takes place. A proof-of-principle device of the digital flow meter was designed, fabricated, and tested. The device was built on foil-based technology. In the proof-of-principle experiments, good agreement was found between set flow rates and the evaporation rates estimated from reading the number of wetted pore structures. The measurement range of the digital flow meter can be tuned and extended in a straightforward manner by changing the pore structure of the device.

  8. Structuring of polymer solutions upon solvent evaporation

    NASA Astrophysics Data System (ADS)

    Schaefer, C.; van der Schoot, P.; Michels, J. J.

    2015-02-01

    The morphology of solution-cast, phase-separated polymers becomes finer with increasing solvent evaporation rate. We address this observation theoretically for a model polymer where demixing is induced by steady solvent evaporation. In contrast to what is the case for a classical, thermal quench involving immiscible blends, the spinodal instability initially develops slowly and the associated length scale is not time invariant but decreases with time as t-1 /2. After a time lag, phase separation accelerates. Time lag and characteristic length exhibit power-law behavior as a function of the evaporation rate with exponents of -2 /3 and -1 /6 . Interestingly, at later stages the spinodal structure disappears completely while a second length scale develops. The associated structure coarsens but does not follow the usual Lifshitz-Slyozov-Wagner kinetics.

  9. Ball feeder for replenishing evaporator feed

    DOEpatents

    Felde, D.K.; McKoon, R.H.

    1993-03-23

    Vapor source material such as uranium, which is to be dropped into a melt in an evaporator, is made into many balls of identical diameters and placed inside a container. An elongated sloping pipe is connected to the container and leads to the evaporator such that these balls can travel sequentially therealong by gravity. A metering valve in this pipe for passing these balls one at a time is opened in response to a signal when it is ascertained by a detector that there is a ball ready to be passed. A gate in the pipe near the evaporator momentarily stops the motion of the traveling ball and is then opened to allow the ball drop into the melt at a reduced speed.

  10. [Evaporating Droplet and Imaging Slip Flows

    NASA Technical Reports Server (NTRS)

    Larson, R. G.

    2002-01-01

    In this report, we summarize work on Evaporating Droplet and Imaging Slip Flows. The work was primarily performed by post-doc Hue Hu, and partially by grad students Lei Li and Danish Chopra. The work includes studies on droplet evaporation and its effects on temperature and velocity fields in an evaporating droplet, new 3-D microscopic particle image velocimetry and direct visualization on wall slip in a surfactant solution. With the exception of the slip measurements, these projects were those proposed in the grant application. Instead of slip flow, the original grant proposed imaging electro-osmotic flows. However, shortly after the grant was issued, the PI became aware of work on electro-osmotic flows by the group of Saville in Princeton that was similar to that proposed, and we therefore elected to carry out work on imaging slip flows rather than electro-osmotic flows.

  11. Potential flow inside an evaporating cylindrical line.

    PubMed

    Petsi, A J; Burganos, V N

    2005-10-01

    An analytical solution to the problem of potential flow inside an evaporating line is obtained. The line is shaped as a half-cylinder lying on a substrate, and evaporates with either pinned or depinned contact lines. The solution is provided through the technique of separation of variables in the velocity potential and stream function formulations. Based on the flow field calculations, it is estimated that the coffee-stain phenomenon should be expected even for uniform evaporation flux throughout the cylindrical surface, provided that the contact lines remain anchored. A simple expression for the velocity potential is also suggested, which reproduces the local velocity vector with excellent accuracy. The vertically averaged velocity is calculated also for other contact line values, revealing for any value an outward liquid flow for pinned lines as opposed to inward flow for depinned lines. PMID:16383581

  12. Evaporative Cooling in a Holographic Atom Trap

    NASA Technical Reports Server (NTRS)

    Newell, Raymond

    2003-01-01

    We present progress on evaporative cooling of Rb-87 atoms in our Holographic Atom Trap (HAT). The HAT is formed by the interference of five intersecting YAG laser beams: atoms are loaded from a vapor-cell MOT into the bright fringes of the interference pattern through the dipole force. The interference pattern is composed of Talbot fringes along the direction of propagation of the YAG beams, prior to evaporative cooling each Talbot fringe contains 300,000 atoms at 50 micro-K and peak densities of 2 x 10(exp 14)/cu cm. Evaporative cooling is achieved through adiabatically decreasing the intensity of the YAG laser. We present data and calculations covering a range of HAT geometries and cooling procedures.

  13. Ball feeder for replenishing evaporator feed

    DOEpatents

    Felde, David K.; McKoon, Robert H.

    1993-01-01

    Vapor source material such as uranium, which is to be dropped into a melt in an evaporator, is made into many balls of identical diameters and placed inside a container. An elongated sloping pipe is connected to the container and leads to the evaporator such that these balls can travel sequentially therealong by gravity. A metering valve in this pipe for passing these balls one at a time is opened in response to a signal when it is ascertained by a detector that there is a ball ready to be passed. A gate in the pipe near the evaporator momentarily stops the motion of the traveling ball and is then opened to allow the ball drop into the melt at a reduced speed.

  14. Evaporation control research, 1955-58

    USGS Publications Warehouse

    Cruse, Robert R.; Harbeck, Guy Earl

    1960-01-01

    One hundred fifty-two compounds and compositions of matter were screened as potential evaporation retardants. The homologous straight-chain fatty alkanols are considered the best materials for retardants. Several methods of application of the alkanols to the reservoir surface were investigated. Although wick-type drippers for the application of liquids and cage rafts for the application of solids appear to be the most promising methods from an economic standpoint, both methods have serious disadvantages. Considerable study was given to reducing biochemical oxidation of the evaporation retardants. Copper in several forms was found adequate as a bacteriostatic agent but posed a potential hazard because of its toxicity. Many other bactericides that were tested were also toxic. Two sets of large-scale field tests have been completed and several others are still in progress. On the larger reservoirs, the reduction of evaporation was not more than 20 percent under the prevailing conditions and the application procedure used. Three major practical problems remain; namely, the effects and action of wind on the monofilm, the effects of biochemical oxidation, and the most effective method of application. Fundamental problems remaining include the effects of various impurities, and the composition of the best evaporation retardant; the long-range effects of monofilms on the limnology of a reservoir, including the transfer of oxygen and carbon dioxide; toxicological aspects of all components of any evaporation-retardant composition, plus toxicology of any composition chosen for large-scale use; and further studies of the calorimetry and thermodynamics involved in the mechanism of evaporation and its reduction by a monofilm.

  15. Evaporation of NaCl solution from porous media with mixed wettability

    NASA Astrophysics Data System (ADS)

    Bergstad, Mina; Shokri, Nima

    2016-05-01

    Evaporation of saline water from porous media is ubiquitous in many processes including soil salinization, crop production, and CO2 sequestration in deep saline acquirer. It is controlled by the transport properties of porous media, atmospheric conditions, and properties of the evaporating saline solution. In the present study, the effects of mixed wettability conditions on the general dynamics of water evaporation from porous media saturated with NaCl solution were investigated. To do so, we conducted a comprehensive series of evaporation experiments using sand mixtures containing different fractions of hydrophobic grains saturated with NaCl solutions. Our results showed that increasing fraction of hydrophobic grains in the mixed wettability sand pack had minor impact on the evaporative mass losses due to the presence of salt whose precipitation patterns were significantly influenced by the mixed wettability condition. Through macroscale and microscale investigations, we found formation of patchy efflorescence in the case of mixed wettability sand pack as opposed to crusty efflorescence in the case of completely hydrophilic porous media. Furthermore, the presence of salty water and hydrophobic grains in the sand pack significantly influenced the general dynamics and morphology of the receding drying front. Our results extend the understanding of the saline water evaporation from porous media with direct applications to various hydrological and engineering processes.

  16. Applicability of post-ionization theory to laser-assisted field evaporation of magnetite

    SciTech Connect

    Schreiber, Daniel K.; Chiaramonti, Ann N.; Gordon, Lyle M.; Kruska, Karen

    2014-12-15

    Analysis of the mean Fe ion charge state from laser-assisted field evaporation of magnetite (Fe3O4) reveals unexpected trends as a function of laser pulse energy that break from conventional post-ionization theory for metals. For Fe ions evaporated from magnetite, the effects of post-ionization are partially offset by the increased prevalence of direct evaporation into higher charge states with increasing laser pulse energy. Therefore the final charge state is related to both the field strength and the laser pulse energy, despite those variables themselves being intertwined when analyzing at a constant detection rate. Comparison of data collected at different base temperatures also show that the increased prevalence of Fe2+ at higher laser energies is possibly not a direct thermal effect. Conversely, the ratio of 16O+:16O2+ is well-correlated with field strength and unaffected by laser pulse energy on its own, making it a better overall indicator of the field evaporation conditions than the mean Fe charge state. Plotting the normalized field strength versus laser pulse energy also elucidates a non-linear dependence, in agreement with previous observations on semiconductors, that suggests a field-dependent laser absorption efficiency. Together these observations demonstrate that the field evaporation process for laser-pulsed oxides exhibits fundamental differences from metallic specimens that cannot be completely explained by post-ionization theory. Further theoretical studies, combined with detailed analytical observations, are required to understand fully the field evaporation process of non-metallic samples.

  17. Investigation of interfacial phenomena and thermocapillary effect on drop evaporation in reduced gravity condition

    NASA Astrophysics Data System (ADS)

    Xie, Jingchang; Lin, Hai

    2013-11-01

    Based on ground-based experiments, a drop evaporation experiment will fly aboard Chinese recoverable satellite in the near future This experiment will focus on the interfacial phenomena of phase chance, heat and mass transfer and the effect of thermocapillary convection on drop evaporation process Close attention will also be paid to the contact angle behavior, the triple line shifting and their relations Our ground-based experiments observed the interior flow field and the gaseous exterior of small suspended evaporating drops, the temperature distributions inside and outside the drops. Both good heat conductor and heat insulating material were used as substrate materials to investigate their influence on heat transfer and surface temperature distribution of an evaporating drop Experimental results indicate that for a drop evaporating in ambient temperature without substrate heating, temperature gradients existed along the drop surface which results in stable thermocapillary convection and cells appeared near the surface throughout entire evaporating process. The thermocapillary convection greatly changed drop's interior temperature distribution and the way of energy and mass transfer. Temperature jump or discontinuity was also measured at drop free surface.

  18. Evaporation of freely suspended single droplets: experimental, theoretical and computational simulations

    NASA Astrophysics Data System (ADS)

    Hołyst, R.; Litniewski, M.; Jakubczyk, D.; Kolwas, K.; Kolwas, M.; Kowalski, K.; Migacz, S.; Palesa, S.; Zientara, M.

    2013-03-01

    Evaporation is ubiquitous in nature. This process influences the climate, the formation of clouds, transpiration in plants, the survival of arctic organisms, the efficiency of car engines, the structure of dried materials and many other phenomena. Recent experiments discovered two novel mechanisms accompanying evaporation: temperature discontinuity at the liquid-vapour interface during evaporation and equilibration of pressures in the whole system during evaporation. None of these effects has been predicted previously by existing theories despite the fact that after 130 years of investigation the theory of evaporation was believed to be mature. These two effects call for reanalysis of existing experimental data and such is the goal of this review. In this article we analyse the experimental and the computational simulation data on the droplet evaporation of several different systems: water into its own vapour, water into the air, diethylene glycol into nitrogen and argon into its own vapour. We show that the temperature discontinuity at the liquid-vapour interface discovered by Fang and Ward (1999 Phys. Rev. E 59 417-28) is a rule rather than an exception. We show in computer simulations for a single-component system (argon) that this discontinuity is due to the constraint of momentum/pressure equilibrium during evaporation. For high vapour pressure the temperature is continuous across the liquid-vapour interface, while for small vapour pressures the temperature is discontinuous. The temperature jump at the interface is inversely proportional to the vapour density close to the interface. We have also found that all analysed data are described by the following equation: da/dt = P1/(a + P2), where a is the radius of the evaporating droplet, t is time and P1 and P2 are two parameters. P1 = -λΔT/(qeffρL), where λ is the thermal conductivity coefficient in the vapour at the interface, ΔT is the temperature difference between the liquid droplet and the vapour far

  19. The WACMOS-ET project - Part 2: Evaluation of global terrestrial evaporation data sets

    NASA Astrophysics Data System (ADS)

    Miralles, D. G.; Jiménez, C.; Jung, M.; Michel, D.; Ershadi, A.; McCabe, M. F.; Hirschi, M.; Martens, B.; Dolman, A. J.; Fisher, J. B.; Mu, Q.; Seneviratne, S. I.; Wood, E. F.; Fernaìndez-Prieto, D.

    2015-10-01

    The WACMOS-ET project aims to advance the development of land evaporation estimates at global and regional scales. Its main objective is the derivation, validation and inter-comparison of a group of existing evaporation retrieval algorithms driven by a common forcing data set. Three commonly used process-based evaporation methodologies are evaluated: the Penman-Monteith algorithm behind the official Moderate Resolution Imaging Spectroradiometer (MODIS) evaporation product (PM-MOD), the Global Land Evaporation Amsterdam Model (GLEAM), and the Priestley and Taylor Jet Propulsion Laboratory model (PT-JPL). The resulting global spatiotemporal variability of evaporation, the closure of regional water budgets and the discrete estimation of land evaporation components or sources (i.e. transpiration, interception loss and direct soil evaporation) are investigated using river discharge data, independent global evaporation data sets and results from previous studies. In a companion article (Part 1), Michel et al. (2015) inspect the performance of these three models at local scales using measurements from eddy-covariance towers, and include the assessment the Surface Energy Balance System (SEBS) model. In agreement with Part 1, our results here indicate that the Priestley and Taylor based products (PT-JPL and GLEAM) perform overall best for most ecosystems and climate regimes. While all three products adequately represent the expected average geographical patterns and seasonality, there is a tendency from PM-MOD to underestimate the flux in the tropics and subtropics. Overall, results from GLEAM and PT-JPL appear more realistic when compared against surface water balances from 837 globally-distributed catchments, and against separate evaporation estimates from ERA-Interim and the Model Tree Ensemble (MTE). Nonetheless, all products manifest large dissimilarities during conditions of water stress and drought, and deficiencies in the way evaporation is partitioned into its

  20. Evaporation of freely suspended single droplets: experimental, theoretical and computational simulations.

    PubMed

    Hołyst, R; Litniewski, M; Jakubczyk, D; Kolwas, K; Kolwas, M; Kowalski, K; Migacz, S; Palesa, S; Zientara, M

    2013-03-01

    Evaporation is ubiquitous in nature. This process influences the climate, the formation of clouds, transpiration in plants, the survival of arctic organisms, the efficiency of car engines, the structure of dried materials and many other phenomena. Recent experiments discovered two novel mechanisms accompanying evaporation: temperature discontinuity at the liquid-vapour interface during evaporation and equilibration of pressures in the whole system during evaporation. None of these effects has been predicted previously by existing theories despite the fact that after 130 years of investigation the theory of evaporation was believed to be mature. These two effects call for reanalysis of existing experimental data and such is the goal of this review. In this article we analyse the experimental and the computational simulation data on the droplet evaporation of several different systems: water into its own vapour, water into the air, diethylene glycol into nitrogen and argon into its own vapour. We show that the temperature discontinuity at the liquid-vapour interface discovered by Fang and Ward (1999 Phys. Rev. E 59 417-28) is a rule rather than an exception. We show in computer simulations for a single-component system (argon) that this discontinuity is due to the constraint of momentum/pressure equilibrium during evaporation. For high vapour pressure the temperature is continuous across the liquid-vapour interface, while for small vapour pressures the temperature is discontinuous. The temperature jump at the interface is inversely proportional to the vapour density close to the interface. We have also found that all analysed data are described by the following equation: da/dt = P(1)/(a + P(2)), where a is the radius of the evaporating droplet, t is time and P(1) and P(2) are two parameters. P(1) = -λΔT/(q(eff)ρ(L)), where λ is the thermal conductivity coefficient in the vapour at the interface, ΔT is the temperature difference between the liquid droplet and the