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1

Organic iodine removal from simulated dissolver off-gas systems utilizing silver-exchanged mordenite  

Microsoft Academic Search

The removal of methyl iodide by adsorption onto silver mordenite was studied using a simulated off-gas from the fuel dissolution step of a nuclear fuel reprocessing plant. The adsorption of methyl iodide on silver mordenite was examined for the effect of NO\\/sub x\\/, humidity, iodine concentration, filter temperature, silver loadings and filter pretreatment. The highest iodine loading achieved in these

Jubin

1981-01-01

2

Organic iodine removal from simulated dissolver off-gas streams using partially exchanged silver mordenite  

SciTech Connect

The removal of methyl iodide by adsorption onto silver mordenite was studied using a simulated off-gas from the fuel dissolution step of a nuclear fuel reprocessing plant. The methyl iodide adsorption of partially exchanged silver mordenite was examined for the effects of NO/sub x/, humidity, filter temperature, and degree of silver exchange. Partially exchanged silver mordenite, in general, achieved significantly higher silver utilizations than the fully exchanged material. Silver utilizations of > 95% were achieved, assuming the formation of AgI. The experimental results indicate that CH/sub 3/I loadings increase proportionally with silver loading up to 5 wt % silver and then appear to level off. Tests conducted to determine the effect of temperature on the loading showed higher loadings at 200/sup 0/C than at either 150 or 250/sup 0/C. The presence of NO, NO/sub 2/, and H/sub 2/O vapor showed negligible effects on the loading of CH/sub 3/I. In contrast to iodine loaded onto fully exchanged silver mordenite, the iodine loaded onto the partially exchanged silver mordenite could not be stripped by either 4.5% hydrogen or 100% hydrogen at temperatures up to 500/sup 0/C. A study of the regeneration characteristics of fully exchanged silver mordenite indicates a decreased adsorbent capacity after complete removal of the iodine with 4.5% hydrogen in the regeneration gas stream at 500/sup 0/C. The loss of adsorbent capacity was much higher for silver mordenite regenerated in a stainless steel filter housing than in a glass filter housing. A cost evaluation for the use of the partially exchanged silver mordenite shows that the cost of the silver mordenite on a once-through basis is < $10/h of operation for a 0.5-t/d reprocessing plant.

Jubin, R.T.

1982-01-01

3

Experimental evaluation of NO\\/sub x\\/ and I retention during the scrubbing of dissolver off-gas  

Microsoft Academic Search

As part of the Consolidated Fuel Reprocessing Program, this study was conducted at the Oak Ridge National Laboratory to investigate the removal of nitrogen oxides from simulated dissolver off-gas, a gas blended to simulate that arising from the dissolution of nuclear fuel in reprocessing operations. Dissolver off-gas contains large quantities of water vapor and nitrogen oxides and much smaller quantities

R. M. Counce; W. S. Groenier; R. T. Jubin

1986-01-01

4

Evaluation of NO/sub x/ scrubber for dissolver off-gas streams  

SciTech Connect

A nitrogen oxides (NO/sub x) scrubber made by Croll-Reynolds Company was evaluated for use in removing NO/sub x/ from dissolver off-gas. Six tests of the unit were made by dissolving finely divided U/sub 3/O/sub 8/ in 2.5-M nitric acid and analyzing the NO/sub x/ concentration of the gas stream at the scrubber inlet and outlet. Two tests used NO gas flow through the dissolver vessel to simulate dissolver off-gas. Scrubber efficiency ranged from 46% to 89%. 10 figures, 1 table.

Hostbjor, G.J.; Higuchi, K.

1982-09-01

5

Aspen simulation of oil shale retort off-gas cleanup with venturi scrubbers  

Microsoft Academic Search

A significant fraction of the product energy from oil shale retorting is contained in the retort off gas. Most oil shale processes use the retort off gas from plant fuel. The HS and NH in retort off gas produce too much SO and NOX to allow burning without a pollution control system. We used the ASPEN flowsheet simulator to model

1984-01-01

6

Single-column-based absorption process for treating dissolver off-gas  

SciTech Connect

The fluorocarbon absorption process for krypton and xenon removal from dissolver off-gas is based on exploitation of solubility differences which exist among noble gases and other gas-phase constituents in the fluorocarbon solvent dichlorofluoromethane (refrigerant-12). Process performance and reliability have been demonstrated on an engineering scale with over 10 years of pilot plant operation, including testing with /sup 85/Kr, /sup 133/Xe, and /sup 131/I. The culmination of this work is a single-column design which results in a simplified process with improved reliability and lower cost. Data are presented summarizing recent single-column development activities. These include data plots depicting decontamination factor vs feed gas flow rate, DF vs process absorption factor (kG/L), and location of the concentration peak via the solvent flow rate. In general, 99% removal is easily obtainable for Kr, Xe, and CO/sub 2/ while attaining concentration factors on the order of 10/sup 3/ to 10/sup 4/. Further concentration of the Kr product is investigated using solid sorbent and cold trapping technologies. Effective removal of entrained fluorocarbon solvent and CO/sub 2/ from the single-column product stream is demonstrated using 13X and 5A molecular sieves, respectively. Additional separation of Xe is studied using a silver mordenite bed and compared to existing methods using cryogenic charcoal beds or selective cold trap sublimation. Regardless of the method for Xe removal, Kr is ultimately concentrated via a simple cold trap to > 90% purity from a feed gas containing 10 ppM. 14 figures.

Eby, R.S.; Little, D.K.; Merriman, J.R.; Stephenson, M.J.

1982-05-21

7

Dynamic simulation aids DWPF off-gas and ventilation design  

Microsoft Academic Search

Dynamic simulation is an effective engineering tool for the evaluation of dynamic systems during the design phase of a project. The primary objective is to gain understanding about all aspects of the dynamic behavior during upset conditions and to use such knowledge to arrive at a design that satisfies all control and performance criteria. On the Defense Waste Processing Facility

K. C. Chiu; N. E. Pabanz; O. T. Asuncion

1986-01-01

8

Numerical Simulation of CO and NO Emissions during Converter Off-Gas Combustion in the Cooling Stack  

Microsoft Academic Search

Oxygen converter steelmaking produces a large amount of high temperature off-gas. During pre- and post-combustion of converter off-gas in the cooling stack, CO concentration at outlet is always over emission standard, and NO emission is still paid little attention. In the paper, CO and NO emissions are investigated during converter off-gas combustion by CFD. The simulation results indicate that CO

Sen Li; Xiaolin Wei

2012-01-01

9

Regulatory Off-Gas Analysis from the Evaporation of Hanford Simulated Waste Spiked with Organic Compounds  

SciTech Connect

After strontium/transuranics removal by precipitation followed by cesium/technetium removal by ion exchange, remaining low activity waste in the Hanford River Protection Project Waste Treatment Plant is to be concentrated by evaporation prior to being mixed with glass formers and vitrified. To provide a technical basis to permit the waste treatment facility, a relatively organic-rich Hanford Tank 241-AN-107 waste simulant was spiked with 14 target volatile, semi-volatile and pesticide compounds, and evaporated under vacuum in a bench-scale natural circulation evaporator fitted with an industrial stack off-gas sampler at the Savannah River Technology Center. An evaporator material balance for the target organics was calculated by combining liquid stream mass and analytical data with off-gas emissions estimates obtained using EPA SW-846 Methods. Volatile and light semi-volatile organic compounds in the waste simulant were found to largely exit through the condenser vent, while heavier semi-volatiles and pesticides generally remain in the evaporator concentrate. An OLI Environmental Simulation Program evaporator model successfully predicted operating conditions and the experimental distribution of the fed target organics exiting in the concentrate, condensate and off-gas streams with the exception of a few semi-volatile and pesticide compounds. Comparison with Henry's Law predictions suggests the OLI ESP model is constrained by available literature data.

Calloway, T.B. Jr.

2003-10-23

10

Continuous gamma scintillation monitor for iodine sup 131 in dissolver off-gas and vessel vent system  

Microsoft Academic Search

As a result of discussions on continuous iodine monitoring, it was requested that our proposal for using a scintillation counter for continuously monitoring iodine in off-gas streams be summarized. The scintillation monitoring system would be substituted for the caustic scrubber monitor system, and should be strongly considered for plant service. The monitor system consists of the sensing unit, a programmer,

1955-01-01

11

Cement solidification of simulated off-gas condensates from vitrification of low-level nuclear waste solutions.  

PubMed

Solidification in a cementitious matrix is a viable alternative for low-level nuclear waste management; it is therefore important to understand the behavior and properties of such wasteforms. We have examined the cementitious solidification of simulated off-gas waste streams resulting from the vitrification of low-level nuclear waste. Different possible methods for scrubbing the off-gasses from a vitrifier give rise to three possible types of waste compositions: acidic (from aqueous dissolution of volatile NOx and POx carried over from the vitrifier), basic (from neutralizing the former with sodium hydroxide), and fully carbonated (arising from a direct-combustion vitrifier). Six binder compositions were tested in which ordinary Portland cement was replaced at different proportions by fly ash and/or ground granulated blast furnace slag. A high solution to binder ratio of 1l/1 kg was used to minimize the volume of the wasteform and 10% attapulgite clay was added to all mixes to ensure that the fresh mix did not segregate prior to setting. The 28-day compressive strengths decreased when a high proportion of cement was replaced with fly ash, but were increased significantly when the cement was replaced with slag. The heats of hydration at early age for the various solids compositions decreased when cement was replaced with either fly ash or slag; however, for the fly ash mix the low heat was also associated with a significant decrease in compressive strength. High curing temperature (60 degrees C) or the use of extra-fine slag did not significantly affect the compressive strength. Recommendations for choice of binder formulations and treatment of off-gas condensates are discussed. PMID:11478621

Katz, A; Brough, A R; Kirkpatrick, R J; Struble, L J; Sun, G K; Young, J F

2001-01-01

12

Surface decontamination of simulated chemical warfare agents using a nonequilibrium plasma with off-gas monitoring  

Microsoft Academic Search

InnovaTek, Inc., Richland, WA, is developing a surface decontamination technology that utilizes active species generated in a nonequilibrium corona plasma. The plasma technology was tested against dimethyl-methyl phosphonate (DMMP), a simulant for the chemical agent Sarin. Gas chromatograph mass spectrometry analysis showed that a greater than four log10 destruction of the DMMP on an aluminum surface was achieved in a

Trevor M. Moeller; M. Lizabeth Alexander; Mark H. Engelhard; Daniel J. Gaspar; Maria L. Luna; Patricia M. Irving

2002-01-01

13

Surface Decontamination of Simulated Chemical Warfare Agents Using a Nonequilibrium Plasma with Off-Gas Monitoring  

SciTech Connect

InnovaTek is developing a surface decontamination technology that utilizes active species generated in a nonequilibrium corona plasma. The plasma technology was tested against DMMP, a simulant for the chemical agent Sarin. GC-MS analysis showed that a greater than four log10 destruction of the DMMP on an aluminum surface was achieved in a 10 minute treatment. An ion-trap mass spectrometer was utilized to collect time-resolved data on the treatment off-gases. These data indicate that only non-toxic fragments of the broken down DMMP molecule were present in the gas phase. The technology is being further refined to develop a product that will not only decontaminate surfaces but will also sense when decontamination is complete

Moeller, Trevor M.; Alexander, M. Lizabeth; Engelhard, Mark H.; Gaspar, Dan J.; Luna, Maria L.; Irving, Patricia M.

2002-08-01

14

Efficient particulate scrubber for glass melter off-gas  

SciTech Connect

Operation of joule-heated, continuous slurry fed melters has demonstrated that off-gas aerosols are generated by entrainment of feed slurry and vaporization of volatile species from the melt. Effective off-gas stream decontamination for these aerosols can be obtained by utilizing a suitably designed and operated wet scrubber system. Results are presented for performance tests conducted with an air aspirating-type venturi scrubber processing a simulated melter off-gas aerosol. Mass removal efficiencies ranged from 99.5 to 99.8%. Details of the testing program and applications for melter off-gas system design are discussed.

Wright, G.T.

1982-01-01

15

Efficient particulate scrubber for glass melter off-gas  

SciTech Connect

Operation of joule-heated, continuous slurry-fed melters has demonstrated that off-gas aerosols are generated by entrainment of feed slurry and vaporization of volatile species from the melt. Effective off-gas stream decontamination for these aerosols can be obtained by utilizing a suitably designed and operated wet scrubber system. Results are presented for performance tests conducted with an air aspirating-type venturi scrubber processing a simulated melter off-gas aerosol. Mass overall removal efficiencies ranged from 99.5 to 99.8%. Details of the testing program and applications for melter off-gas system design are discussed.

Wright, G.T.

1983-01-01

16

Off-Gas Control Project.  

National Technical Information Service (NTIS)

A program to develop and study off-gas abatement techniques has recently been initiated at Whiteshell Nuclear Research Establishment (WNRE). This report provides information on the properties and expected behaviour of reprocessing plant off-gases, and out...

D. F. Torgerson I. M. Smith

1978-01-01

17

Adsorption Model for Off-Gas Separation  

SciTech Connect

The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed in gPROMS software. Inputs include gas stream constituents, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. It models dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions for a multiple component gas stream. The simulation outputs component concentrations along the column length as a function of time from which the breakthrough data is obtained. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data will be input into the adsorption model to develop a model specific for iodine adsorption on silver mordenite as well as model(s) specific for krypton and xenon adsorption. The model will be validated with experimental breakthrough curves. Another future off-gas modeling goal is to develop a model for the unit operation absorption. The off-gas models will be made available via the server or web for evaluation by customers.

Veronica J. Rutledge

2011-03-01

18

FINAL REPORT REGULATORY OFF GAS EMISSIONS TESTING ON THE DM1200 MELTER SYSTEM USING HLW AND LAW SIMULANTS VSL-05R5830-1 REV 0 10/31/05  

SciTech Connect

The operational requirements for the River Protection Project - Waste Treatment Plant (RPP-WTP) Low Activity Waste (LAW) and High Level Waste (HLW) melter systems, together with the feed constituents, impose a number of challenges to the off-gas treatment system. The system must be robust from the standpoints of operational reliability and minimization of maintenance. The system must effectively control and remove a wide range of solid particulate matter, acid mists and gases, and organic constituents (including those arising from products of incomplete combustion of sugar and organics in the feed) to concentration levels below those imposed by regulatory requirements. The baseline design for the RPP-WTP LAW primary off-gas system includes a submerged bed scrubber (SBS), a wet electrostatic precipitator (WESP), and a high efficiency particulate air (HEPA) filter. The secondary off-gas system includes a sulfur-impregnated activated carbon bed (AC-S), a thermal catalytic oxidizer (TCO), a single-stage selective catalytic reduction NOx treatment system (SCR), and a packed-bed caustic scrubber (PBS). The baseline design for the RPP-WTP HLW primary off-gas system includes an SBS, a WESP, a high efficiency mist eliminator (HEME), and a HEPA filter. The HLW secondary off-gas system includes a sulfur-impregnated activated carbon bed, a silver mordenite bed, a TCO, and a single-stage SCR. The one-third scale HLW DM1200 Pilot Melter installed at the Vitreous State Laboratory (VSL) was equipped with a prototypical off-gas train to meet the needs for testing and confirmation of the performance of the baseline off-gas system design. Various modifications have been made to the DM1200 system as the details of the WTP design have evolved, including the installation of a silver mordenite column and an AC-S column for testing on a slipstream of the off-gas flow; the installation of a full-flow AC-S bed for the present tests was completed prior to initiation of testing. The DM1200 system was reconfigured to enable testing of the baseline HLW or LAW off-gas trains to perform off-gas emissions testing with both LAW and HLW simulants in the present work. During 2002 and 2003, many of these off-gas components were tested individually and in an integrated manner with the DM1200 Pilot Melter. Data from these tests are being used to support engineering design confirmation and to provide data to support air permitting activities. In fiscal year 2004, the WTP Project was directed by the Office of River Protection (ORP) to comply with Environmental Protection Agency (EPA) Maximum Achievable Control Technology (MACT) requirements for organics. This requires that the combined melter and off-gas system have destruction and removal efficiency (DRE) of >99.99% for principal organic dangerous constituents (PODCs). In order to provide confidence that the melter and off-gas system are able to achieve the required DRE, testing has been directed with both LAW and HLW feeds. The tests included both 'normal' and 'challenge' WTP melter conditions in order to obtain data for the potential range of operating conditions for the WTP melters and off-gas components. The WTP Project, Washington State Department of Ecology, and ORP have agreed that naphthalene will be used for testing to represent semi-volatile organics and allyl alcohol will be used to represent volatile organics. Testing was also performed to determine emissions of halides, metals, products of incomplete combustion (PICs), dioxins, furans, coplanar PCBs, total hydrocarbons, and COX and NOX, as well as the particle size distribution (PSD) of particulate matter discharged at the end of the off-gas train. A description of the melter test requirements and analytical methods used is provided in the Test Plan for this work. Test Exceptions were subsequently issued which changed the TCO catalyst, added total organic emissions (TOE) to exhaust sampling schedule, and allowing modification of the test conditions in response to attainable plenum temperatures as well as temperature increases in the sulfur impr

KRUGER AA; MATLACK KS; GONG W; BARDAKCI T; D'ANGELO NA; BRANDYS M; KOT WK; PEGG IL

2011-12-29

19

Dynamic Absorption Model for Off-Gas Separation  

Microsoft Academic Search

Modeling and simulations will aid in the future design of U.S. advanced reprocessing plants for the recovery and recycle of actinides in used nuclear fuel. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are

Veronica J. Rutledge

2011-01-01

20

Dynamic Modeling of Radioactive Melter Off-Gas Systems  

Microsoft Academic Search

Dynamic models to simulate the performance of off-gas treatment and control systems for the High Level Waste (HLW) and Low Activity Waste (LAW) melters in the proposed Waste Treatment Plant at the Hanford Site have been developed using Aspen Custom Modeler(TM). The models are designed to give accurate pressure drops through the off-gas equipment and to show the dynamic behavior

2003-01-01

21

Methods of Off-Gas Flammability Control for DWPF Melter Off-Gas System at Savannah River Site  

SciTech Connect

Several key operating variables affecting off-gas flammability in a slurry-fed radioactive waste glass melter are discussed, and the methods used to prevent potential off-gas flammability are presented. Two models have played a central role in developing such methods. The first model attempts to describe the chemical events occurring during the calcining and melting steps using a multistage thermodynamic equilibrium approach, and it calculates the compositions of glass and calcine gases. Volatile feed components and calcine gases are fed to the second model which then predicts the process dynamics of the entire melter off-gas system including off-gas flammability under both steady state and various transient operating conditions. Results of recent simulation runs are also compared with available data

Choi, A.S. [Westinghouse Savannah River Company, AIKEN, SC (United States); Iverson, D.C.

1996-05-02

22

Glass melter off-gas system  

DOEpatents

This invention is comprised of an apparatus and method for melting glass in a glass melter in such a way as to reduce deposition of particulates in the off-gas duct. Deposit accumulation is reduced by achieving an off-gas velocity above approximately 15 meters/second and an off-gas temperature as close as possible to, but not higher than, the glass softening point. Because the deposits are largely water-soluble, those that do form on the interior surface of the duct can be readily removed by injecting water or steam directly into the off-gas duct from its entrance or exit.

Jantzen, C.M.

1992-12-31

23

Dynamic Absorption Model for Off-Gas Separation.  

National Technical Information Service (NTIS)

Modeling and simulations will aid in the future design of U.S. advanced reprocessing plants for the recovery and recycle of actinides in used nuclear fuel. The specific fuel cycle separation process discussed in this report is the off-gas treatment system...

V. J. Rutledge

2011-01-01

24

Off-gas treatment and krypton disposal in HTGR-fuel element reprocessing  

Microsoft Academic Search

Krypton, tritium and iodine are separated from burner off-gas by CO-liquification and rectification at room tempearture. Krypton is concentrated in the lower boiling fraction, while tritium and iodine are concentrated in the higher boiling fraction (AKUT-process). The dissolver off-gas is decontaminated by a cryogenic process. Based on safety and economy, the disposal of compressed krypton confined in steel cylinders by

M. Laser; H. Beaujean; J. Bohnenstingl; P. Filss; M. Heidendael; S. Mastera; E. Merz; H. Vygen

1972-01-01

25

Technology of off-gas treatment for liquid-fed ceramic melters  

SciTech Connect

The technology for treating off gas from liquid-fed ceramic melters (LFCMs) has been under development at the Pacific Northwest Laboratory since 1977. This report presents the off-gas technology as developed at PNL and by others to establish a benchmark of development and to identify technical issues. Tests conducted on simulated (nonradioactive) wastes have provided data that allow estimation of melter off-gas composition for a given waste. Mechanisms controlling volatilization of radionuclides and noxious gases are postulated, and correlations between melter operation and emissions are presented. This report is directed to those familiar with LFCM operation. Off-gas treatment systems always require primary quench scrubbers, aerosol scrubbers, and final particulate filters. Depending on the composition of the off gas, equipment for removal of ruthenium, iodine, tritium, and noxious gases may also be needed. Nitrogen oxides are the most common noxious gases requiring treatment, and can be controlled by aqueous absorption or catalytic conversion with ammonia. High efficiency particulate air (HEPA) filters should be used for final filtration. The design criteria needed for an off-gas system can be derived from emission regulations and composition of the melter feed. Conservative values for melter off-gas composition can be specified by statistical treatment of reported off-gas data. Statistical evaluation can also be used to predict the frequency and magnitude of normal surge events that occur in the melter. 44 refs., 28 figs., 17 tabs.

Scott, P.A.; Goles, R.W.; Peters, R.D.

1985-05-01

26

MATHEMATICAL SIMULATION TOOLS FOR DEVELOPING DISSOLVED OXYGEN TMDLS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This paper presents an extended abstract of a research paper describing four commonly used dissolved oxygen (DO) simulation models. The concentration of DO in surface waters is one of the most commonly used indicators of river and stream health. Regulators and other professionals are increasingly r...

27

Experimental investigation of the distribution of krypton during the removal and fixation of CO/sub 2/ from simulated HTGR fuel reprocessing off-gas by the CO/sub 2/-Ca(OH)/sub 2/ slurry reaction  

SciTech Connect

An experimental investigation was conducted to determine the behavior of krypton during the removal and fixation of CO/sub 2/ from simulated HTGR fuel reprocessing off-gas in a mechanically agitated gas-Ca(OH)/sub 2/ slurry contactor. For CO/sub 2/ removal, decontamination factors (DFs) in the range of 10/sup 2/ to 10/sup 3/ were obtained with a single contactor; DFs for CO/sub 2/ of 10/sup 3/ to 10/sup 4/ were obtained during operation of two contactors in series. For the primary CO/sub 2/ removal step in a single contactor, 0.5 to 1% of the krypton in the feed gas was retained in the slurry. Additional treatment resulted in further reduction of the slurry krypton content by a factor of 10/sup 2/. (Overall, evacuation of the product slurry during agitation was the most desirable add-on process.) Thus, the quantity of krypton in the feed that was retained in the product CaCO/sub 3/ slurry could be restricted to 0.01 to 0.001% by using a combination of primary processes and add-on treatments. Models are presented that predict the distributions of both CO/sub 2/ and krypton during gas treatment in Ca(OH)/sub 2/ slurries for both single-contactor and contactors-in-series operation.

Holladay, D.W.

1982-06-01

28

FINAL REPORT REGULATORY OFF GAS EMISSIONS TESTING ON THE DM1200 MELTER SYSTEM USING HLW AND LAW SIMULANTS VSL-05R5830-1 REV 0 10\\/31\\/05  

Microsoft Academic Search

The operational requirements for the River Protection Project - Waste Treatment Plant (RPP-WTP) Low Activity Waste (LAW) and High Level Waste (HLW) melter systems, together with the feed constituents, impose a number of challenges to the off-gas treatment system. The system must be robust from the standpoints of operational reliability and minimization of maintenance. The system must effectively control and

KRUGER AA; MATLACK KS; GONG W; BARDAKCI T; DANGELO NA; BRANDYS M; KOT WK; PEGG IL

2011-01-01

29

Cold Dissolved Saltcake Waste Simulant Development, Preparation, and Analysis  

SciTech Connect

CH2M Hill Hanford Group, Inc. is identifying and developing supplemental process technologies to accelerate the Hanford tank waste cleanup mission. Bulk vitrification, containerized grout, and steam reforming are three technologies under consideration for treatment of the radioactive saltcake wastes in 68 single-shell tanks. To support development and testing of these technologies, Pacific Northwest National Laboratory (PNNL) was tasked with developing a cold dissolved saltcake simulant formulation to be representative of an actual saltcake waste stream, preparing a 25-L batch of the simulant, and analyzing the composition of the batch to assure conformance to formulation targets. Lacking a defined composition for dissolved actual saltcake waste, PNNL used available tank waste composition information and an equilibrium chemistry model (Environmental Simulation Program, ESP) to predict the concentrations of analytes in solution. Observations of insoluble solids in initial laboratory preparations for the model predicted formulation prompted minor modifications in the concentration of phosphate and silicon in the final simulant formulation. The analytical results for the 25-L simulant batch agree within the expected measurement accuracy (~10%) of the target concentrations and are highly consistent for replicate measurements, with a few minor exceptions. The instrumental analyses indicate that the batch of solution adequately reflects the as-formulated simulant composition. In parallel with the simulant development effort, a nominally 5-M (molar) sodium actual sodium waste solution was prepared at the Hanford site from a limited number of tank waste samples. Since this actual waste solution was also to be used for testing of the supplemental treatment technologies, the modeled simulant formulation was predicated on the composite of waste samples used to prepare it. Subsequently, the actual waste solution was filtered and pretreated to remove radioactive cesium at PNNL and then analyzed using the same instrumentation and procedures applied to the simulant samples. The overall agreement of measured simulant and actual waste solution compositions is better than 10% for the most concentrated species including sodium, nitrate, hydroxide, carbonate, and nitrite. While the magnitude of the relative difference in the simulant and actual waste composition is large (>20% difference) for a few analytes (aluminum, chromium, fluoride, potassium, and total organic carbon), the absolute differences in concentration are in general not appreciable. Our evaluation is that these differences in simulant and actual waste solutions should have a negligible impact on supplemental treatment process testing.

Rassat, Scot D. (BATTELLE (PACIFIC NW LAB)); Mahoney, Lenna A. (BATTELLE (PACIFIC NW LAB)); Russell, Renee L. (BATTELLE (PACIFIC NW LAB)); Bryan, Samuel A. (BATTELLE (PACIFIC NW LAB)); Sell, Rachel L. (BATTELLE (PACIFIC NW LAB))

2003-02-25

30

Simulation of hydrodynamics, temperature, and dissolved oxygen in Bull Shoals Lake, Arkansas, 1994-1995  

USGS Publications Warehouse

and dissolved-oxygen concentration through time. However, results from both scenarios for water temperature and dissolved-oxygen concentration were within the boundaries of the error between measured and simulated water column profile values.

Galloway, Joel M.; Green, W. Reed

2003-01-01

31

Cold Dissolved Saltcake Waste Simulant Development, Preparation, and Analysis  

SciTech Connect

CH2M HILL Hanford Group, Inc. is identifying and developing supplemental process technologies to accelerate the Hanford tank waste cleanup mission. Bulk vitrification, containerized grout, and steam reforming are three technologies under consideration for treatment of the radioactive saltcake wastes in 68 single-shell tanks. To support development and testing of these technologies, Pacific Northwest National Laboratory (PNNL) was tasked with developing a cold dissolved saltcake simulant formulation to be representative of an actual saltcake waste stream, preparing 25- and 100-L batches of the simulant, and analyzing the composition of the batches to ensure conformance to formulation targets. Lacking a defined composition for dissolved actual saltcake waste, PNNL used available tank waste composition information and an equilibrium chemistry model (Environmental Simulation Program [ESP{trademark}]) to predict the concentrations of analytes in solution. Observations of insoluble solids in initial laboratory preparations for the model-predicted formulation prompted reductions in the concentration of phosphate and silicon in the final simulant formulation. The analytical results for the 25- and 100-L simulant batches, prepared by an outside vendor to PNNL specifications, agree within the expected measurement accuracy ({approx}10%) of the target concentrations and are highly consistent for replicate measurements, with a few minor exceptions. In parallel with the production of the 2nd simulant batch (100-L), a 1-L laboratory control sample of the same formulation was carefully prepared at PNNL to serve as an analytical standard. The instrumental analyses indicate that the vendor prepared batches of solution adequately reflect the as-formulated simulant composition. In parallel with the simulant development effort, a nominal 5-M (molar) sodium actual waste solution was prepared at the Hanford Site from a limited number of tank waste samples. Because this actual waste solution w as also to be used for testing the supplemental treatment technologies, the modeled simulant formulation was predicated on the composite of waste samples used to prepare it. Subsequently, the actual waste solution was filtered and pretreated to remove radioactive cesium at PNNL and then analyzed using the same instrumentation and procedures applied to the simulant samples. The overall agreement of measured simulant and actual waste solution compositions is better than {+-}10% for the most concentrated species including sodium, nitrate, hydroxide, carbonate, and nitrite. While the magnitude of the relative difference in the simulant and actual waste composition is large (>20% difference) for a few analytes (aluminum, chromium, fluoride, potassium, and total organic carbon), the absolute differences in concentration are in general not appreciable. Our evaluation is that these differences in simulant and actual waste solutions should have a negligible impact on bulk vitrification and containerized grout process testing, while the impact of the low aluminum concentration on steam reforming is yet to be determined.

Rassat, Scot D.; Mahoney, Lenna A.; Russell, Renee L.; Bryan, Samuel A.; Sell, Rachel L.

2003-05-13

32

Carbon Dioxide-Krypton Separation and Radon Removal from Nuclear-Fuel-Reprocessing off-Gas Streams.  

National Technical Information Service (NTIS)

General Atomic Company (GA) is conducting pilot-plant-scale tests that simulate the treatment of radioactive and other noxious volatile and gaseous constituents of off-gas streams from nuclear reprocessing plants. This paper reports the results of enginee...

P. M. Hirsch K. Y. Higuchi L. Abraham

1982-01-01

33

Treatment of nitrous off-gas from dissolution of sludges  

SciTech Connect

Several configurations have been reviewed for the NO{sub x} removal of dissolver off-gas. A predesign has been performed and operating conditions have been optimized. Simple absorption columns seems to be sufficient. NHC is in charge of the treatment of sludges containing mainly uranium dioxide and metallic uranium. The process is based on the following processing steps a dissolution step to oxidize the pyrophoric materials and to dissolve radionuclides (uranium, plutonium, americium and fission products), a solid/liquid separation to get rid of the insoluble solids (to be disposed at ERDF), an adjustment of the acid liquor with neutronic poisons, and neutralization of the acid liquor with caustic soda. The dissolution step generates a flow of nitrous fumes which was evaluated in a previous study. This NO{sub x} flow has to be treated. The purpose of this report is to study the treatment process of the nitrous vapors and to 0482 perform a preliminary design. Several treatment configurations are studied and the most effective process option with respect to the authorized level of discharge into atmosphere is discussed. As a conclusion, recommendations concerning the unit preliminary design are given.

Flament, T.A.

1998-08-25

34

Method and apparatus for off-gas composition sensing  

Microsoft Academic Search

An apparatus and method for non-intrusive collection of off-gas data in a steelmaking furnace includes structure and steps for transmitting a laser beam through the off-gas produced by a steelmaking furnace, for controlling the transmitting to repeatedly scan the laser beam through a plurality of wavelengths in its tuning range, and for detecting the laser beam transmitted through the off-gas

David Keith Ottesen; Sarah Williams Allendorf; Gary Lee Hubbard; David Ezechiel Rosenberg

1999-01-01

35

Proposed Strategies for DWPF Melter Off-Gas Surge Control  

Microsoft Academic Search

Off-gas surging is inherent to the operation of slurry-fed melters. Although the melter design and the feed chemistry are both known to significantly affect off-gas surging, the frequency and intensity of surges are in essence unpredictable. In typical off-gas surges, both condensable and non condensable flows spike simultaneously. Condensable or steam surges have been observed to occur as the boiling

A. S. Choi

2004-01-01

36

Off-gas recycle for VOC emission control: Conceptual model  

Microsoft Academic Search

Capture and recycle of off-gas from a complete-mix activated-sludge reactor was evaluated as an alternative VOC-control strategy to reduce the volume and cost of off-gas treatment. A mathematical model was developed to predict the fraction of individual influent VOC compounds that are biodegraded, stripped, and discharged in the liquid and gaseous effluents of an activated-sludge reactor with off-gas recycle. The

Y. Argaman; J. L. Musterman

2009-01-01

37

Heat exchangers and thermal energy storage concepts for the off-gas heat of steelmaking devices  

NASA Astrophysics Data System (ADS)

The fluctuating thermal emissions of electric arc furnaces require energy storage systems to provide downstream consumers with a continuous amount of thermal energy or electricity. Heat recovery systems based on thermal energy storage are presented. A comparison of different thermal energy storage systems has been performed. For the purpose, suitable heat exchangers for the off-gas heat have been developed. Dynamic process simulations of the heat recovery plants were necessary to check the feasibility of the systems and consider the non-steady-state off-gas emissions of the steelmaking devices. The implementation of a pilot plant into an existing off-gas duct of an electric arc furnace was required to check the real behavior of the heat exchanger and determine suitable materials in view of corrosion issues. The pilot plant is presented in this paper.

Steinparzer, T.; Haider, M.; Fleischanderl, A.; Hampel, A.; Enickl, G.; Zauner, F.

2012-11-01

38

Study on the numerical simulation of the dissolved air releaser in the energy microalgae recovery device  

Microsoft Academic Search

Dissolv ed air flotation recovery is one of the feasible microalgae recovery methods. Choose the standard k - (; turbulent calculation model to conduct numerical simulation to the flow field of the dissolved air releaser of the energy microalgae recovery device, and study the structural parameters and power dissipation. The result of the numerical simulation conducted to the value of

Wang Guang-hui; Kuang Ya-li; Lin Zhe; Chen Xue

2011-01-01

39

COUPLED FREE AND DISSOLVED PHASE TRANSPORT: NEW SIMULATION CAPABILITIES AND PARAMETER INVERSION  

EPA Science Inventory

The vadose zone free-phase simulation capabilities of the US EPA Hydrocarbon Spill Screening Model (HSSM)have been linked with the 3-D multi-species dissolved-phase contaminant transport simulator MT3DMS....

40

Process for removing nitrogen dioxide from off-gas  

SciTech Connect

The disclosure relates to a process for removing nitrogen dioxide from off-gas. To this end, the disclosure provides for the off-gas to be intimately contacted with a suspension consisting of red phosphorus and a liquid being inert with respect to red phosphorus, e.g. water.

Lehr, K.; Heymer, G.

1984-11-13

41

Technology survey for real-time monitoring of plutonium in a vitrifier off-gas system  

SciTech Connect

We surveyed several promising measurement technologies for the real-time monitoring of plutonium in a vitrifier off-gas system. The vitrifier is being developed by Westinghouse Savannah River Corp. and will be used to demonstrate vitrification of plutonium dissolved in nitric acid for fissile material disposition. The risk of developing a criticality hazard in the off-gas processing equipment can be managed by using available measurement technologies. We identified several potential technologies and methods for detecting plutonium that are sensitive enough to detect the accumulation of a mass sufficient to form a criticality hazard. We recommend gross alpha-monitoring technologies as the most promising option for Westinghouse Savannah River Corp. to consider because that option appears to require the least additional development. We also recommend further consideration for several other technologies because they offer specific advantages and because gross alpha-monitoring could prove unsuitable when tested for this specific application.

Berg, J.M.; Veirs, D.K.

1996-01-01

42

Methods of Off-Gas Flammability Control for DWPF Melter Off-Gas System at Savannah River Site.  

National Technical Information Service (NTIS)

Several key operating variables affecting off-gas flammability in a slurry-fed radioactive waste glass melter are discussed, and the methods used to prevent potential off-gas flammability are presented. Two models have played a central role in developing ...

A. S. Choi D. C. Iverson

1996-01-01

43

Simulation Analysis for HB-Line Dissolver Mixing  

SciTech Connect

In support of the HB-Line Engineering agitator mixing project, flow pattern calculations have been made for a 90{sup o} apart and helical pitch agitator submerged in a flat tank containing dissolver baskets. The work is intended to determine maximum agitator speed to keep the dissolver baskets from contacting the agitator for the nominal tank liquid level. The analysis model was based on one dissolver basket located on the bottom surface of the flat tank for a conservative estimate. The modeling results will help determine acceptable agitator speeds and tank liquid levels to ensure that the dissolver basket is kept from contacting the agitator blade during HB-Line dissolver tank operations. The numerical modeling and calculations have been performed using a computational fluid dynamics approach. Three-dimensional steady-state momentum and continuity equations were used as the basic equations to estimate fluid motion driven by an agitator with four 90{sup o} pitched blades or three flat blades. Hydraulic conditions were fully turbulent (Reynolds number about 1 x 10{sup 5}). A standard two-equation turbulence model ({kappa},{var_epsilon}), was used to capture turbulent eddy motion. The commercial finite volume code, Fluent [5], was used to create a prototypic geometry file with a non-orthogonal mesh. Hybrid meshing was used to fill the computational region between the round-edged tank bottom and agitator regions. The nominal calculations and a series of sensitivity runs were made to investigate the impact of flow patterns on the lifting behavior of the dissolver basket. At high rotational speeds and low tank levels, local turbulent flow reaches the critical condition for the dissolver basket to be picked up from the tank floor and to touch the agitator blades during the tank mixing operations. This is not desirable in terms of mixing performance. The modeling results demonstrate that the flow patterns driven by the agitators considered here are not strong enough to lift up the dissolver basket for the agitator speeds up to 2500 rpm. The results also show that local velocity magnitudes for the three-blade flat plate agitator are at maximum three times smaller than the helical fourblade one. Table 5 and Table 6 summarize the results.

Lee, S

2006-03-22

44

MATHEMATICAL SIMULATION TOOLS FOR DEVELOPING DISSOLVED OXYGEN TMDLS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The amount of dissolved oxygen (DO) in water is one of the most commonly used indicators of river and stream health. In most fresh water systems, aquatic fauna become stressed as DO drops below 4 or 5 mg L-1. Under extended hypoxic (low DO) or anoxic (no DO) conditions, most higher forms of life are...

45

Carbon dioxide-krypton separation and radon removal from nuclear-fuel-reprocessing off-gas streams  

SciTech Connect

General Atomic Company (GA) is conducting pilot-plant-scale tests that simulate the treatment of radioactive and other noxious volatile and gaseous constituents of off-gas streams from nuclear reprocessing plants. This paper reports the results of engineering-scale tests performed on the CO/sub 2//krypton separation and radon holdup/decay subsystems of the GA integrated off-gas treatment system. Separation of CO/sub 2/ from krypton-containing gas streams is necessary to facilitate subsequent waste processing and krypton storage. Molecular sieve 5A achieved this separation in dissolver off-gas streams containing relatively low krypton and CO/sub 2/ concentrations and in krypton-rich product streams from processes such as the krypton absorption in liquid carbon dioxide (KALC) process. The CO/sub 2//krypton separation unit is a 30.5-cm-diameter x 1.8-m-long column containing molecular sieve 5A. The loading capacity for CO/sub 2/ was determined for gas mixtures containing 250 ppM to 2.2% CO/sub 2/ and 170 to 750 ppM krypton in either N/sub 2/ or air. Gas streams rich in CO/sub 2/ were diluted with N/sub 2/ to reduce the temperature rise from the heat of adsorption, which would otherwise affect loading capacity. The effluent CO/sub 2/ concentration prior to breakthrough was less than 10 ppM, and the adsorption capacity for krypton was negligible. Krypton was monitored on-line with a time-of-flight mass spectrometer and its concentration determined quantitatively by a method of continuous analysis, i.e., selected-ion monitoring. Radon-220 was treated by holdup and decay on a column of synthetic H-mordenite. The Rn-220 concentration was monitored on-line with flow-through diffused-junction alpha detectors. Single-channel analyzers were utilized to isolate the 6.287-MeV alpha energy band characteristic of Rn-220 decay from energy bands due to daughter products.

Hirsch, P.M.; Higuchi, K.Y.; Abraham, L.

1982-07-01

46

Evaluation of a Continuous Solid Bowl Centrifuge for Processing Simulated Rover Dissolver Effluent.  

National Technical Information Service (NTIS)

Pilot-plant studies using a plant-scale continuous Bird centrifuge were made to determine the solids--liquid separation and subsequent solids washing efficiencies for processing simulated Rover dissolver effluent. The studies were undertaken to provide a ...

J. S. Vavruska J. A. Rindfleisch

1975-01-01

47

Numerical Simulation of Salinity and Dissolved Oxygen at Perdido Bay and Adjacent Coastal Ocean  

EPA Science Inventory

Environmental Fluid Dynamic Code (EFDC), a numerical estuarine and coastal ocean circulation hydrodynamic model, was used to simulate the distribution of the salinity, temperature, nutrients and dissolved oxygen (DO) in Perdido Bay and adjacent Gulf of Mexico. External forcing fa...

48

High-level waste vitrification off-gas cleanup technology  

Microsoft Academic Search

This brief overview is intended to be a basis for discussion of needs and problems existing in the off-gas clean-up technology. A variety of types of waste form and processes are being developed in the United States and abroad. A description of many of the processes can be found in the Technical Alternative Documents (TAD). Concurrently, off-gas processing systems are

1980-01-01

49

Adsorption Model for Off-Gas Separation  

Microsoft Academic Search

The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of

Veronica J. Rutledge

2011-01-01

50

Methods of Off-Gas Flammability Control for DWPF Melter Off-Gas System at Savannah River Site  

Microsoft Academic Search

Several key operating variables affecting off-gas flammability in a slurry-fed radioactive waste glass melter are discussed, and the methods used to prevent potential off-gas flammability are presented. Two models have played a central role in developing such methods. The first model attempts to describe the chemical events occurring during the calcining and melting steps using a multistage thermodynamic equilibrium approach,

A. S. Choi; D. C. Iverson

1996-01-01

51

Off-gas characteristics of liquid-fed joule-heated ceramic melters  

SciTech Connect

The off-gas characteristics of liquid-fed joule-heated ceramic melters have been investigated as a function of melter operational condition and simulated waste feed composition. The results of these studies have established the identity and behavior patterns of gaseous emissions, the characteristics of melter-generated aerosols, the nature and magnitude of melter effluent losses and the factors affecting melter operational performance. 8 figures, 16 tables.

Goles, R.W.; Sevigny, G.J.

1982-06-01

52

Simulation of hydrodynamics, temperature, and dissolved oxygen in Beaver Lake, Arkansas, 1994-1995  

USGS Publications Warehouse

The tailwaters of Beaver Lake and other White River reservoirs support a cold-water trout fishery of significant economic yield in northwestern Arkansas. The Arkansas Game and Fish Commission has requested an increase in existing minimum flows through the Beaver Lake dam to increase the amount of fishable waters downstream. Information is needed to assess the impact of additional minimum flows on temperature and dissolved-oxygen qualities of reservoir water above the dam and the release water. A two-dimensional, laterally averaged hydrodynamic, thermal and dissolved-oxygen model was developed and calibrated for Beaver Lake, Arkansas. The model simulates surface-water elevation, currents, heat transport and dissolved-oxygen dynamics. The model was developed to assess the impacts of proposed increases in minimum flows from 1.76 cubic meters per second (the existing minimum flow) to 3.85 cubic meters per second (the additional minimum flow). Simulations included assessing (1) the impact of additional minimum flows on tailwater temperature and dissolved-oxygen quality and (2) increasing initial water-surface elevation 0.5 meter and assessing the impact of additional minimum flow on tailwater temperatures and dissolved-oxygen concentrations. The additional minimum flow simulation (without increasing initial pool elevation) appeared to increase the water temperature (<0.9 degrees Celsius) and decrease dissolved oxygen concentration (<2.2 milligrams per liter) in the outflow discharge. Conversely, the additional minimum flow plus initial increase in pool elevation (0.5 meter) simulation appeared to decrease outflow water temperature (0.5 degrees Celsius) and increase dissolved oxygen concentration (<1.2 milligrams per liter) through time. However, results from both minimum flow scenarios for both water temperature and dissolved oxygen concentration were within the boundaries or similar to the error between measured and simulated water column profile values.

Haggard, Brian; Green, W. Reed

2002-01-01

53

Watershed modeling of dissolved oxygen and biochemical oxygen demand using a hydrological simulation Fortran program  

Microsoft Academic Search

Several inland water bodies in the St. Louis Bay watershed have been identified as being potentially impaired due to low level of dissolved oxygen (DO). In order to calculate the total maximum daily loads (TMDL), a standard watershed model supported by U.S. Environmental Protection Agency, Hydrological Simulation Program Fortran (HSPF), was used to simulate water temperature, DO, and bio-chemical oxygen

Zhijun Liu; Janna M. Kieffer; William L. Kingery; David H. Huddleston; Faisal Hossain

2007-01-01

54

COUPLED FREE AND DISSOLVED PHASE TRANSPORT: NEW SIMULATION CAPABILITIES AND PARAMETER INVERSION  

EPA Science Inventory

The vadose zone free-phase simulation capabilities of the US EPA Hydrocarbon Spill Screening Model (HSSM) (Weaver et al., 1994) have been linked with the 3-D multi-species dissolved-phase contaminant transport simulator MT3DMS (Zheng and Wang, 1999; Zheng, 2005). The linkage pro...

55

Simulation of hydrodynamics, temperature, and dissolved oxygen in Norfork Lake, Arkansas, 1994-1995  

USGS Publications Warehouse

Outflow from Norfork Lake and other White River reservoirs support a cold-water trout fishery of significant economic yield in north-central Arkansas and south-central Missouri. The Arkansas Game and Fish Commission has requested an increase in existing minimum flows through the Norfork Lake dam to increase the amount of fishable waters downstream. Information is needed to assess the impact of increased minimum flows on temperature and dissolved-oxygen concentrations of reservoir water and the outflow. A two-dimensional, laterally averaged, hydrodynamic, temperature, and dissolved-oxygen model was developed and calibrated for Norfork Lake, located on the Arkansas-Missouri State line. The model simulates water-surface elevation, heat transport, and dissolved-oxygen dynamics. The model was developed to assess the impacts of proposed increases in minimum flow from 1.6 cubic meter per second (the existing minimum flow) to 8.5 cubic meters per second (the increased minimum flow). Simulations included assessing the impact of (1) increased minimum flows and (2) increased minimum flows with increased water-surface elevation of 1.1 meter in Norfork Lake on outflow temperatures and dissolved-oxygen concentrations. The increased minimum flow simulation (without increasing initial water-surface elevation) appeared to increase the water temperature and decrease dissolved-oxygen concentration in the outflow. Conversely, the increased minimum flow and initial increase in water-surface elevation (1.1 meter) simulation appeared to decrease outflow water temperature and increase dissolved-oxygen concentration through time. However, results from both scenarios for water temperature and dissolved-oxygen concentration were within the boundaries or similar to the error between measured and simulated water column profile values.

Galloway, Joel M.; Green, W. Reed

2002-01-01

56

CHARACTERIZATION OF DWPF MELTER OFF-GAS QUENCHER SAMPLE  

SciTech Connect

The Savannah River National Laboratory (SRNL) recently received a deposit sample from the Melter Primary Off Gas System (POG) of the Defense Waste Processing Facility (DWPF). This sample was composed of material that had been collected while the quencher was in operation January 27, 2011 through March 31, 2011. DWPF requested, through a technical assistance request, characterization of the melter off-gas deposits by x-ray diffraction (XRD), scanning electron microscopy (SEM), and chemical analysis. The purpose of the Melter Off-Gas System is to reduce the amount of radioactive particles and mercury in the gases vented to the atmosphere. Gases emitted from the melter pass through the primary film cooler, quencher, Off-Gas Condensate Tank (OGCT), Steam Atomized Scrubbers (SAS), a condenser, a high efficiency mist eliminator, and a high efficiency particulate air filter, before being vented to the Process Vessel Vent System. The film coolers cool the gases leaving the melter vapor space from {approx}750 C to {approx}375 C, by introducing air and steam to the flow. In the next step, the quencher cools the gas to about 60 C by bringing the condensate from the OGCT in contact with the effluent (Figure 1). Most of the steam in the effluent is then condensed and the melter vapor space pressure is reduced. The purpose of the OGCT is to collect and store the condensate formed during the melter operation. Condensate from the OGCT is circulated to the SAS and atomized with steam. This atomized condensate is mixed with the off-gas to wet and join the particulate which is then removed in the cyclone. The next stage incorporates a chilled water condenser which separates the vapors and elemental mercury from the off-gas steam. Primary off-gas deposit samples from the DWPF melter have previously been analyzed. In 2003, samples from just past the film cooler, from the inlet of the quencher and inside the quencher were analyzed at SRNL. It was determined that the samples were a mixture of sludge and glass frit. The major component was Si along with Fe, Al, and other elements in the radioactive waste being processed. The deposits analyzed also contained U-235 fission products and actinide elements. Prior to that, deposits in the off-gas system in the DWPF nonradioactive half scale melter and the one-tenth scale integrated DWPF melter system were analyzed and determined to be mixtures of alkali rich chlorides, sulfates, borates, and fluorides entrained with iron oxides, spinels and frit particles formed by vapor-phase transport and condensation. Additional work was performed in 2007 in which researchers similarly found the deposits to be a combination of sludge and frit particles.

Newell, J.

2011-11-14

57

ART CCIM Phase II-A Off-Gas System Evaluation Test Plan  

SciTech Connect

This test plan defines testing to be performed using the Idaho National Laboratory (INL) engineering-scale cold crucible induction melter (CCIM) test system for Phase II-A of the Advanced Remediation Technologies (ART) CCIM Project. The multi-phase ART-CCIM Project is developing a conceptual design for replacing the joule-heated melter (JHM) used to treat high level waste (HLW) in the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) with a cold crucible induction melter. The INL CCIM test system includes all feed, melter off-gas control, and process control subsystems needed for fully integrated operation and testing. Testing will include operation of the melter system while feeding a non-radioactive slurry mixture prepared to simulate the same type of waste feed presently being processed in the DWPF. Process monitoring and sample collection and analysis will be used to characterize the off-gas composition and properties, and to show the fate of feed constituents, to provide data that shows how the CCIM retrofit conceptual design can operate with the existing DWPF off-gas control system.

Nick Soelberg; Jay Roach

2009-01-01

58

CHARACTERIZATION OF DWPF MELTER OFF-GAS QUENCHER SAMPLE  

Microsoft Academic Search

The Savannah River National Laboratory (SRNL) recently received a deposit sample from the Melter Primary Off Gas System (POG) of the Defense Waste Processing Facility (DWPF). This sample was composed of material that had been collected while the quencher was in operation January 27, 2011 through March 31, 2011. DWPF requested, through a technical assistance request, characterization of the melter

2011-01-01

59

Materials performance in off-gas systems containing iodine  

Microsoft Academic Search

During the reprocessing of spent reactor fuel elements, iodine is released to gas streams from which it is ultimately removed by conversion to nonvolatile iodic acid. Under some conditions iodine can produce severe corrosion in off-gas lines; in this study these conditions were established. Iron- and nickel-based alloys containing more than 6% molybdenum, such as Hastelloy G (7%), Inconel 625

J. A. Beavers; W. E. Berry; J. C. Griess

1981-01-01

60

High-Level Waste Vitrification off-Gas Cleanup Technology.  

National Technical Information Service (NTIS)

This brief overview is intended to be a basis for discussion of needs and problems existing in the off-gas clean-up technology. A variety of types of waste form and processes are being developed in the United States and abroad. A description of many of th...

M. S. Hanson

1980-01-01

61

Simulated climate change effects on dissolved oxygen characteristics in ice-covered lakes  

Microsoft Academic Search

A deterministic, one-dimensional model is presented which simulates daily dissolved oxygen (DO) profiles and associated water temperatures, ice covers and snow covers for dimictic and polymictic lakes of the temperate zone. The lake parameters required as model input are surface area (AS), maximum depth (HMAX), and Secchi depth as a measure of light attenuation and trophic state. The model is

Xing Fang; Heinz G. Stefan

1997-01-01

62

Simulation of thermal\\/dissolved oxygen habitat for fishes in lakes under different climate scenarios  

Microsoft Academic Search

Fish habitat is strongly constrained by water temperature and available dissolved oxygen (DO). Thermal\\/DO habitat for cool-water fish in small lakes was therefore determined from simulated daily water temperature and DO profiles. Twenty-seven types of lakes were simulated with past (19611979) climate conditions observed at 209 weather stations in the contiguous USA as input, and with a 2CO2 climate scenario

Xing Fang; Heinz G. Stefan; John G. Eaton; J. Howard McCormickc; Shoeb R. Alam

2004-01-01

63

Simulation of hydrodynamics, temperature, and dissolved oxygen in Table Rock Lake, Missouri, 1996-1997  

USGS Publications Warehouse

Outflow from Table Rock Lake and other White River reservoirs support a cold-water trout fishery of substantial economic yield in south-central Missouri and north-central Arkansas. The Missouri Department of Conservation has requested an increase in existing minimum flows through the Table Rock Lake Dam from the U.S. Army Corps of Engineers to increase the quality of fishable waters downstream in Lake Taneycomo. Information is needed to assess the effect of increased minimum flows on temperature and dissolved- oxygen concentrations of reservoir water and the outflow. A two-dimensional, laterally averaged, hydrodynamic, temperature, and dissolved-oxygen model, CE-QUAL-W2, was developed and calibrated for Table Rock Lake, located in Missouri, north of the Arkansas-Missouri State line. The model simulates water-surface elevation, heat transport, and dissolved-oxygen dynamics. The model was developed to assess the effects of proposed increases in minimum flow from about 4.4 cubic meters per second (the existing minimum flow) to 11.3 cubic meters per second (the increased minimum flow). Simulations included assessing the effect of (1) increased minimum flows and (2) increased minimum flows with increased water-surface elevations in Table Rock Lake, on outflow temperatures and dissolved-oxygen concentrations. In both minimum flow scenarios, water temperature appeared to stay the same or increase slightly (less than 0.37 ?C) and dissolved oxygen appeared to decrease slightly (less than 0.78 mg/L) in the outflow during the thermal stratification season. However, differences between the minimum flow scenarios for water temperature and dissolved- oxygen concentration and the calibrated model were similar to the differences between measured and simulated water-column profile values.

Green, W. Reed; Galloway, Joel M.; Richards, Joseph M.; Wesolowski, Edwin A.

2003-01-01

64

Simulations of underwater plumes of dissolved oil in the Gulf of Mexico  

NASA Astrophysics Data System (ADS)

A simple model of the temperature-dependent biological decay of dissolved oil is embedded in an ocean-climate model and used to simulate underwater plumes of dissolved and suspended oil originating from a point source in the northern Gulf of Mexico, with an upper-bound supply rate estimated from the contemporary analysis of the Deepwater Horizon blowout. The behavior of plumes at different depths is found to be determined by the combination of sheared current strength and the vertical profile of decay rate. For all plume scenarios, toxic levels of dissolved oil remain confined to the northern Gulf of Mexico, and abate within weeks after the spill stops. An estimate of oxygen consumption due to microbial oxidation of hydrocarbons suggests that a deep plume of hydrocarbons could lead to localized regions of prolonged hypoxia near the source, but only when oxidation of methane is included.

Adcroft, Alistair; Hallberg, Robert; Dunne, John P.; Samuels, Bonita L.; Galt, J. A.; Barker, Christopher H.; Payton, Debra

2010-09-01

65

Microwave off-gas treatment apparatus and process  

DOEpatents

The invention discloses a microwave off-gas system in which microwave energy is used to treat gaseous waste. A treatment chamber is used to remediate off-gases from an emission source by passing the off-gases through a susceptor matrix, the matrix being exposed to microwave radiation. The microwave radiation and elevated temperatures within the combustion chamber provide for significant reductions in the qualitative and quantitative emissions of the gas waste stream.

Schulz, Rebecca L. (Aiken, SC); Clark, David E. (Gainesville, FL); Wicks, George G. (North Aiken, SC)

2003-01-01

66

Characterization of Off Gas Flow Surges in the DWPF Melter  

Microsoft Academic Search

The Defense Waste Processing Facility (DWPF) is currently producing radioactive canisters containing vitrified high-level waste. A slurry of high-level waste and glass frit is fed into a joule-heated melter where the mixture is dried, calcined, and melted. The off gases produced are treated in an off gas system designed to remove radioactive particulate and volatile components before exhausting clean gases

Calloway; T. B. Jr

1999-01-01

67

Cesium determination for the DWPF off-gas system performance test  

Microsoft Academic Search

In an effort to determine the cesium decontamination factors (DF`s) of the Defense Waste Processing Facility (DWPF) melter off-gas system at the Savannah River Site, the system was verified during an off-gas performance test. The off-gas performance test occurred during the DWPF waste Qualification Campaigns, WP-16 and WP-17. The verification of the off-gas system, which eliminated the need for a

M. K. Andrews; H. H. Elder; W. T. Boyce

1996-01-01

68

Test results from the GA technologies engineering-scale off-gas treatment system  

SciTech Connect

One method for reducing the volume of HTGR fuel prior to reprocessing or spent fuel storage is to crush and burn the graphite fuel elements. The burner off-gas (BOG) contains radioactive components, principally H-3, C-14, Kr-85, I-129, and Rn-220, as well as chemical forms such as CO/sub 2/, CO, O/sub 2/, and SO/sub 2/. The BOG system employs components designed to remove these constitutents. Test results are reported for the iodine and SO/sub 2/ adsorbers and the CO/HT oxidizer. Silver-based iodine adsorbents were found to catalyze the premature conversion of CO to CO/sub 2/. Subsequent tests showed that iodine removal could not be performed downstream of the CO/HT oxidizer since iodine in the BOG system rapidly deactivated the Pt-coated alumina CO catalyst. Lead-exchanged zeolite (PbX) was found to be an acceptable alternative for removing iodine from BOG without CO conversion. Intermittent and steady-state tests of the pilot-plant SO/sub 2/ removal unit containing sodium-exchanged zeolite (NaX) demonstrated that decontamination factors greater than or equal to 100 could be maintained for up to 50 h. In a reprocessing flowsheet, the solid product from the burners is dissolved in nitric or Thorex acid. The dissolver off-gas (DOG) contains radioactive components H-3, Kr-85, I-129, Rn-220 plus chemical forms such as nitrogen oxides (NO/sub x/). In the pilot-scale system at GA, iodine is removed from the DOG by adsorption. Tests of iodine removal have been conducted using either silver-exchanged mordenite (AgZ) or AgNO/sub 3/-impregnated silica gel (AC-6120). Although each sorbent performed well in the presence of NO/sub x/, the silica gel adsorbent proved more efficient in silver utilization and, thus, more cost effective.

Jensen, D.D.; Olguin, L.J.; Wilbourn, R.G.

1984-06-01

69

Role of dissolved salts in thermophoresis of DNA: Lattice-Boltzmann-based simulations  

NASA Astrophysics Data System (ADS)

We use a lattice Boltzmann based Brownian dynamics simulation to investigate the dependence of DNA thermophoresis on its interaction with dissolved salts. We find the thermal diffusion coefficient DT depends on the molecule size, in contrast with previous simulations without electrostatics. The measured ST also depends on the Debye length. This suggests thermophoresis of DNA is influenced by the electrostatic interactions between the polymer beads and the salt ions. However, when electrostatic forces are weak, DNA thermophoresis is not found, suggesting that other repulsive forces such as the excluded volume force prevent thermal migration.

Hammack, Audrey; Chen, Yeng-Long; Pearce, Jennifer Kreft

2011-03-01

70

Cooler and particulate separator for an off-gas stack  

DOEpatents

This report describes an off-gas stack for a melter, furnace or reaction vessel comprising an air conduit leading to two sets of holes, one set injecting air into the off-gas stack near the melter plenum and the second set injecting air downstream of the first set. The first set injects air at a compound angle, having both downward and tangential components, to create a reverse vortex flow, counter to the direction of flow of gas through the stack and also along the periphery of the stack interior surface. Air from the first set of holes prevents recirculation zones from forming and the attendant accumulation of particulate deposits on the wall of the stack and will also return to the plenum any particulate swept up in the gas entering the stack. The second set of holes injects air in the same direction as the gas in the stack to compensate for the pressure drop and to prevent the concentration of condensate in the stack. A set of sprayers, receiving water from a second conduit, is located downstream of the second set of holes and sprays water into the gas to further cool it.

Wright, G.T.

1991-04-08

71

Process for off-gas particulate removal and apparatus therefor  

DOEpatents

In the event of a breach in the off-gas line of a melter operation requiring closure of the line, a secondary vessel vent line is provided with a particulate collector utilizing atomization for removal of large particulates from the off-gas. The collector receives the gas containing particulates and directs a portion of the gas through outer and inner annular channels. The collector further receives a fluid, such as water, which is directed through the outer channel together with a second portion of the particulate-laden gas. The outer and inner channels have respective ring-like termination apertures concentrically disposed adjacent one another on the outer edge of the downstream side of the particulate collector. Each of the outer and inner channels curves outwardly away from the collector's centerline in proceeding toward the downstream side of the collector. Gasflow in the outer channel maintains the fluid on the channel's wall in the form of a "wavy film," while the gas stream from the inner channel shears the fluid film as it exits the outer channel in reducing the fluid to small droplets. Droplets formed by the collector capture particulates in the gas stream by one of three mechanisms: impaction, interception or Brownian diffusion in removing the particulates. The particulate-laden droplets are removed from the fluid stream by a vessel vent condenser or mist eliminator.

Carl, Daniel E. (Orchard Park, NY)

1997-01-01

72

Numerical simulation of dissolved oxygen concentration in water flow over stepped spillways.  

PubMed

This study developed an improved Eulerian model for the simulation of an air-water flow field over stepped spillways. The improved drag model applied different drag coefficients for bubbles and for free surface flows or gas cavities. Void fraction and turbulence correction were used in determining the bubble drag coefficient. The calculated air entrainment and air-water velocity could be adapted using these parameters. With the improved drag model, the Eulerian simulations predicted the location of the inception point, the distributions of air void fraction, velocity distributions, and pressure distributions. The change in the dissolved oxygen (DO) concentration from upstream of the stepped spillways, to downstream, was simulated based on the improved computational fluid dynamics model and the transport equation for DO transferring. The numerical DO concentration coincided with the experimental results. Therefore, the improved CFD model and the numerical methods presented here can provide possible optimization tools for strong air entrainment flows. PMID:23789573

Cheng, Xiangju; Chen, Xuewei

2013-05-01

73

Limits for the new DWPF melter off-gas jumper I. D  

Microsoft Academic Search

In order to minimize solids deposition in the off-gas line between the primary film cooler and the quencher, Savannah River Laboratory (SRL) recommended earlier that a new DWPF melter off-gas jumper be built which would increase the off-gas velocity from less than 40 ft\\/s under the original design to at least 55 ft\\/s, excluding the melter air inleakage. Two design

1992-01-01

74

Limits for the new DWPF melter off-gas jumper I.D  

Microsoft Academic Search

In order to minimize solids deposition in the off-gas line between the primary film cooler and the quencher, Savannah River Laboratory (SRL) recommended earlier that a new DWPF melter off-gas jumper be built which would increase the off-gas velocity from less than 40 ft\\/s under the original design to at least 55 ft\\/s, excluding the melter air inleakage. Two design

1992-01-01

75

Dynamic Modelling of an Industrial Smelter Furnace and Converter Off-gas System  

Microsoft Academic Search

In smelters, metal ores or concentrates are smelted to reduce a metal oxide to a metal through a series of reactions and processes. In a smelting process, a large amount of off-gas emissions are often generated, which can cause serious environmental and plant hygiene problems if not properly treated. Off-gas systems extract and treat the off-gas emissions, and ensure that

Helen Shang; Megan Dillabough; Phillip Nelson; Bryan Salt

76

Method for the recovery of clean pyrolysis off-gas and a rotary recycling means therefor  

Microsoft Academic Search

A method and apparatus for stripping entrained organic vapor and solid particulate matter from a pyrolytic off-gas stream is disclosed. The off-gas is introduced at the top of a conical chamber having a variable speed ''squirrel cage'' rotor at its top. The wet, dirty, off-gas is drawn into the rotor from below and impinged upon the chamber walls which causes

L. W. Elston; D. R. Hurst

1981-01-01

77

Dissolved Organic Phosphorus Production during Simulated Phytoplankton Blooms in a Coastal Upwelling System.  

PubMed

Dissolved organic phosphorus (DOP) is increasingly recognized as an important phosphorus source to marine primary producers. Despite its importance, the production rate and fate of DOP is poorly understood. In this study, patterns of DOP production were evaluated by tracking the evolution of DOP during simulated phytoplankton blooms initiated with nutrient amended surface waters, relative to controls, from the Oregon (USA) coastal upwelling system. Nitrogen (N) and phosphorus (P) additions were used to decouple DOP production and hydrolysis by inducing or repressing, respectively, community alkaline phosphatase activity. In order to examine the progression of nutrient uptake and DOP production under upwelling versus relaxation conditions, two experiments were initiated with waters collected during upwelling events, and two with waters collected during relaxation events. Maximum [under (+P) conditions] and minimum [under (+N) conditions] DOP production rates were calculated and applied to in situ DOP levels to evaluate which end-member rate most closely approximates the in situ DOP production rate at the four study sites in this coastal system. Increases in DOP concentration occurred by day-5 in control treatments in all experiments. N treatments displayed increased chlorophyll a, increased alkaline phosphatase activity, and yielded lower net DOP production rates relative to controls, suggesting that DOP levels were depressed as a consequence of increased hydrolysis of bioavailable DOP substrates. Phosphorus additions resulted in a significant net production of DOP at all stations, but no increase in chlorophyll a relative to control treatments. The contrasting patterns in DOP production between treatments suggests that changes in the ambient dissolved inorganic nitrogen:dissolved inorganic phosphorus (DIN:DIP) ratio could exert profound control over DOP production rates in this system. Patterns of DOP production across the different experiments also suggest that bathymetry-driven differences in water residence times can influence DOP cycling. Taken together, these factors may impact the potential export of DOP to offshore ecosystems. PMID:22888326

Ruttenberg, K C; Dyhrman, S T

2012-08-06

78

Simulations of Mixing and Transport of Dissolved Waste Discharged From a Submerged Aquaculture pen  

NASA Astrophysics Data System (ADS)

The present study focuses on understanding the transport and fate of dissolved wastes from an aquaculture pen in near-coastal environments using the hydrodynamic code SUNTANS, which uses unstructured grids to compute flows at very high resolution. Simulations of the pollutant concentration field (in time and space) as a function of the local environment (stratification, bathymetry, wind), flow conditions (tides, currents), and the location of the pen were performed. The fish-pen causes partial blockage of the water flow, causing deceleration of the approaching flow and the formation of a downstream wake. Results of both the near-field (area within 10 to 20 pen diameters of fish-pen site) as well as the far-field behavior of the pollutant field will be presented. The results provide an understanding of the impact of aquaculture fish-pens on coastal water quality.

Venayagamoorthy, S. K.; Fringer, O. B.; Koseff, J. R.; Naylor, R. L.

2007-05-01

79

Design and operating considerations for off-gas systems in nuclear processing plants  

Microsoft Academic Search

The General Electric Company, prime contractor to the Atomic Energy Commission at the Hanford, Washington Plant has been concerned for many years with the safe and economical disposal of off-gas from nuclear processing plants. Considerable experience in off-gas disposal has been gained in operating the older Bismuth Phosphate Plants and in the design and operation of the newer Redox and

Michels

1958-01-01

80

High-tech computerized off-gas combustion treatment and apparatus  

Microsoft Academic Search

This patent describes an exhaust system adapted for the selective control of the types and concentrations of gaseous, ionic, colloidal or particulate matter emitted to the atmosphere in the off-gas of a combustion unit. It comprises: chemical treatment chamber means defined by first wall means, off-gas inlet means in the first wall means, and outlet means in the first wall

Valentino

1992-01-01

81

Numerical simulations of aquaculture dissolved waste transport in a coastal embayment  

NASA Astrophysics Data System (ADS)

The present study focuses on understanding the transport and fate of dissolved wastes from aquaculture pens in near-coastal environments using the hydrodynamics code SUNTANS (Stanford Unstructured Nonhydrostatic Terrain-following Adaptive Navier- Stokes Simulator), which employs unstructured grids to compute flows in the coastal ocean at very high resolution. Simulations of a pollutant concentration field (in time and space) as a function of the local environment (bathymetry, rotation), flow conditions (tides, wind-induced currents and wind stress), and the location of the pens were performed to study their effects on the evolution of the waste plume. The presence of the fish farm pens causes partial blockage of the flow, leading to the deceleration of the approaching flow and formation of downstream wakes. Results of both the near-field area (area within 10 to 20 pen diameters of the fish-pen site) as well as far-field behavior of the pollutant field are presented. These results highlight for the first time the importance of the wake vortex dynamics on the evolution of the near-field plume as well as the rotation of the earth on the far-field plume. The results provide an understanding of the impact of aquaculture fish-pens on coastal water quality.

Venayagamoorthy, Subhas; Fringer, Oliver; Koseff, Jeffrey; Naylor, Rosamond

2008-11-01

82

Observations and Numerical Simulation Model Analysis Results of Dissolved Oxygen Characteristics in an Enclosed Coastal Sea, Osaka Bay  

NASA Astrophysics Data System (ADS)

In order to reproduce changes of the dissolved oxygen concentration in summer in the vicinity of the Nanko thermal power plant, located in the inner part of Osaka Bay, a numerical simulation model was developed. According to the model results, daily fluctuation of dissolved oxygen concentration in the surface layer is high in June, the early stratification period, because of instability of stratification and after July. The dissolved oxygen concentration gradually decreases from a level of 6 to 17 mg/L in June to a level of 6 to 9 mg/L in July in the vicinity of the Nanko thermal power plant. Both the observations and model values near the depth of the thermal power plant outlet are 3 to 5 mg/L, which is considered not to affect the water quality of dissolved oxygen. Our simulation model should be able to reproduce the characteristics of dissolved oxygen concentration during the stratification period in the vicinity of the Nanko thermal power plant.

Hasegawa, Kazuyuki; Kiyono, Michiyasu; Yokota, Mizurou; Akimoto, Yasushi; Marumo, Keiyu; Ichikawa, Tetsuya; Hasegawa, Kouichi; Yanagawa, Ryouichi

83

Simulation of Temperature, Nutrients, Biochemical Oxygen Demand, and Dissolved Oxygen in the Catawba River, South Carolina, 1996-97  

USGS Publications Warehouse

Time-series plots of dissolved-oxygen concentrations were determined for various simulated hydrologic and point-source loading conditions along a free-flowing section of the Catawba River from Lake Wylie Dam to the headwaters of Fishing Creek Reservoir in South Carolina. The U.S. Geological Survey one-dimensional dynamic-flow model, BRANCH, was used to simulate hydrodynamic data for the Branched Lagrangian Transport Model. Waterquality data were used to calibrate the Branched Lagrangian Transport Model and included concentrations of nutrients, chlorophyll a, and biochemical oxygen demand in water samples collected during two synoptic sampling surveys at 10 sites along the main stem of the Catawba River and at 3 tributaries; and continuous water temperature and dissolved-oxygen concentrations measured at 5 locations along the main stem of the Catawba River. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to watertemperature boundary data due to the effect of temperature on reaction kinetics and the solubility of dissolved oxygen. Of the model coefficients, the simulated dissolved-oxygen concentration was most sensitive to the biological oxidation rate of nitrite to nitrate. To demonstrate the utility of the Branched Lagrangian Transport Model for the Catawba River, the model was used to simulate several water-quality scenarios to evaluate the effect on the 24-hour mean dissolved-oxygen concentrations at selected sites for August 24, 1996, as simulated during the model calibration period of August 23 27, 1996. The first scenario included three loading conditions of the major effluent discharges along the main stem of the Catawba River (1) current load (as sampled in August 1996); (2) no load (all point-source loads were removed from the main stem of the Catawba River; loads from the main tributaries were not removed); and (3) fully loaded (in accordance with South Carolina Department of Health and Environmental Control National Discharge Elimination System permits). Results indicate that the 24-hour mean and minimum dissolved-oxygen concentrations for August 24, 1996, changed from the no-load condition within a range of - 0.33 to 0.02 milligram per liter and - 0.48 to 0.00 milligram per liter, respectively. Fully permitted loading conditions changed the 24-hour mean and minimum dissolved-oxygen concentrations from - 0.88 to 0.04 milligram per liter and - 1.04 to 0.00 milligram per liter, respectively. A second scenario included the addition of a point-source discharge of 25 million gallons per day to the August 1996 calibration conditions. The discharge was added at S.C. Highway 5 or at a location near Culp Island (about 4 miles downstream from S.C. Highway 5) and had no significant effect on the daily mean and minimum dissolved-oxygen concentration. A third scenario evaluated the phosphorus loading into Fishing Creek Reservoir; four loading conditions of phosphorus into Catawba River were simulated. The four conditions included fully permitted and actual loading conditions, removal of all point sources from the Catawba River, and removal of all point and nonpoint sources from Sugar Creek. Removing the point-source inputs on the Catawba River and the point and nonpoint sources in Sugar Creek reduced the organic phosphorus and orthophosphate loadings to Fishing Creek Reservoir by 78 and 85 percent, respectively.

Feaster, Toby D.; Conrads, Paul A.; Guimaraes, Wladmir B.; Sanders, Curtis L., Jr.; Bales, Jerad D.

2003-01-01

84

Mitigation of energy intensity of an industrial off-gas cleaning system using process engineering solutions  

Microsoft Academic Search

In smelting processes, a large amount of off-gas emission is often generated, which can cause serious environmental and plant hygiene problems if not properly treated. Off-gas cleaning systems extract and treat the hazardous emissions, and ensure that the smelter operation is in accordance with environmental and industrial hygiene regulations. To this end, it is paramount that a well-designed control structure

Antonio C. B. de Araujo; Romildo P. Brito; Helen Shang

2009-01-01

85

Statistical methods to monitor the West Valley off-gas system  

Microsoft Academic Search

The off-gas system for the ceramic melter operated at the West Valley Demonstration Project at West Valley, NY, is monitored during melter operation. A one-at-a-time method of monitoring the parameters of the off-gas system is not statistically sound. Therefore, multivariate statistical methods appropriate for the monitoring of many correlated parameters will be used. Monitoring a large number of parameters increases

Eggett

1990-01-01

86

Minimizing leakage from a smelter off-gas system by enhanced control  

Microsoft Academic Search

The off-gas handling system is a vital component of a smelter and it is essential that it operates in accordance with environmental regulations. A key feature of the off-gas management system is maintaining a slightly negative system pressure to prevent gas leakage, such as SO2, out into the work and external environments. To enhance sustainable development, there is also growing

H. Shang; J. A. Scott

2011-01-01

87

Combustion characteristics of mixture of anode off gas and LNG in reformer  

Microsoft Academic Search

Fuel processing system which converts hydrocarbon fuel into hydrogen rich gas (by stream reforming, partial oxidation, auto-thermal reforming) needs high temperature environment (6001000C). Generally, anode off gas or mixture of anode off gas and LNG are used as input gas for a fuel reformer. In order to constitute efficient and low emission burner system for fuel reformer, it is necessary

Jae Young Lee; Pil Hyong Lee; Chang Soo Park; Bong Il Park; Sang Soon Hwang

2011-01-01

88

Glass melter off-gas system pluggages: Cause, significance, and remediation  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. Experimental glass melters, used to develop the vitrification process, have occasionally experienced problems with pluggage of the off-gas line with solid deposits. The deposits were determined to be mixtures of alkali rich chlorides, sulfates, borates, and fluorides with entrained insoluble particles of Fe{sub 2}O{sub 3} spinel, and frit. The distribution and location of the alkali deposits throughout the off-gas system indicate that the deposits form by vapor-phase transport and condensation. Condensation of the alkali-rich phases cements the entrained particulates causing the off-gas system pluggages. The identification of vapor phase transport as the operational mechanism causing off-gas system pluggages indicates that deposition can be effectively eliminated by increasing the off-gas velocity. The cementitious alkali borates, halides, and sulfates comprising the off-gas line deposits were determined to be water soluble. Thus pluggage can be effectively removed with water and/or steam.

Jantzen, C.M.

1991-12-31

89

Glass melter off-gas system pluggages: Cause, significance, and remediation  

SciTech Connect

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass. Experimental glass melters, used to develop the vitrification process, have occasionally experienced problems with pluggage of the off-gas line with solid deposits. The deposits were determined to be mixtures of alkali rich chlorides, sulfates, borates, and fluorides with entrained insoluble particles of Fe{sub 2}O{sub 3} spinel, and frit. The distribution and location of the alkali deposits throughout the off-gas system indicate that the deposits form by vapor-phase transport and condensation. Condensation of the alkali-rich phases cements the entrained particulates causing the off-gas system pluggages. The identification of vapor phase transport as the operational mechanism causing off-gas system pluggages indicates that deposition can be effectively eliminated by increasing the off-gas velocity. The cementitious alkali borates, halides, and sulfates comprising the off-gas line deposits were determined to be water soluble. Thus pluggage can be effectively removed with water and/or steam.

Jantzen, C.M.

1991-01-01

90

NUMERICAL SIMULATION ON SEASONAL VARIATION IN DISSOLVED OXYGEN TENSION IN LAKE BIWA  

Microsoft Academic Search

A three-dimensional ecosystem model is developed for analysis of seasonal variation in dissolved oxygen tension in Lake Biwa. The ecosystem model consists of physical and chemical-biological submodels. The physical submodel is the hydrodynamic model driven directly by observed net surface heat flux. The chemical-biological submodel is a eutrophic level food web model, which includes phytoplankton, zooplankton, particulate and dissolved organic

Daisuke Kitazawa; Michio Kumagai

91

Detailed Design Data Package item 3.9a: Cadmium buildup in off-gas lines  

SciTech Connect

Waste currently stored at the Hanford Reservation in underground double-shell and single-shell tanks is being considered for vitrification and disposal. To achieve this, Hanford is conducting a Hanford Waste Vitrification Plant Technology Development Project melter campaign. In this campaign, a requirement was identified to quantify the amount of cadmium depositing in the off-gas line between the liquid-fed ceramic melter and the submerged bed scrubber. This issue of cadmium volatility was raised due to the limited data on cadmium volatility in HLW vitrification. Prior to the start of slurry processing, the off-gas line sections were removed and inspects. Any pre-existing deposits were removed. Following the melter campaign, the lines were again removed and solids deposits were sampled and the quantity of deposits were estimated. The data presented in this package include chemical analysis of feed, glass, line deposits, in-ling off-gas stream, and SBS condensate samples. Process data includes melter feeding and glass production rates, off- gas flow rate, and plenum and off-gas stream temperatures.

Perez, J.M.; Buchmiller, W.C.; Anderson, L.D.; Whittington, G.A.

1996-04-01

92

Method for the recovery of clean pyrolysis off-gas and a rotary recycling means therefor  

SciTech Connect

A method and apparatus for stripping entrained organic vapor and solid particulate matter from a pyrolytic off-gas stream is disclosed. The off-gas is introduced at the top of a conical chamber having a variable speed ''squirrel cage'' rotor at its top. The wet, dirty, off-gas is drawn into the rotor from below and impinged upon the chamber walls which causes part of the organic vapor to condense and flow to the chamber bottom, thereby cleaning the chamber walls. A portion of the impinged gas is recirculated through the rotor while the remainder exits at the chamber bottom. The ratio of recycled gas to through gas is controlled by the speed of the rotor. Heating and cooling coils on the chamber walls are operable to control the rate of condensation.

Elston, L.W.; Hurst, D.R.

1981-07-14

93

IMPACT OF MELTER INTERNAL DESIGN ON OFF-GAS FLAMMABILITY  

SciTech Connect

The purpose of this study was to: (1) identify the more dominant design parameters that can serve as the quantitative measure of how prototypic a given melter is, (2) run the existing DWPF models to simulate the data collected using both DWPF and non-DWPF melter configurations, (3) confirm the validity of the selected design parameters by determining if the agreement between the model predictions and data is reasonably good in light of the design and operating conditions employed in each data set, and (4) run Computational Fluid Dynamics (CFD) simulations to gain new insights into how fluid mixing is affected by the configuration of melter internals and to further apply the new insights to explaining, for example, why the agreement is not good.

Choi, A.; Lee, S.

2012-05-30

94

Design and operation of a submerged bed scrubber for off-gas scrubbing  

SciTech Connect

Operation of a submerged bed scrubber has been characterized well enough to accurately estimate the collection efficiency for aerosols in an off-gas treatment system. The device has the advantages of a high degree of reliability and minimal control requirements. Correlations have been developed that allow direct specification of the design variables that are required to achieve a desire collection efficiency. The decontamination factors achievable through proper design and efficient operation are well within the acceptable range for a primary scrubber in nuclear off-gas treatment systems.

Scott, P.A.; Ruecker, C.M.

1986-09-01

95

Photochemical degradation of chromophoric-dissolved organic matter exposed to simulated UV-B and natural solar radiation  

Microsoft Academic Search

Photochemical degradation of chromophoric-dissolved organic matter (CDOM) by UV-B radiation decreases CDOM absorption in the\\u000a UV region and fluorescence intensity, and alters CDOM composition. CDOM absorption, fluorescence, and the spectral slope indicating\\u000a the CDOM composition were studied using 0.22-?m-filtered samples of Meiliang Bay water from Lake Taihu that were exposed to\\u000a short-term (012h) simulated UV-B radiation and long-term (012 days)

Yunlin Zhang; Mingliang Liu; Boqiang Qin; Sheng Feng

2009-01-01

96

Defining Dissolving  

NSDL National Science Digital Library

In this introductory activity, learners discover that sugar and food coloring dissolve in water but neither dissolves in oil. Based on their observations, learners can conclude that both solids and liquids can dissolve, but they don't necessarily dissolve in all liquids. Through this activity, learners will refine their definition of dissolve.

Kessler, James H.; Galvan, Patricia M.

2007-01-01

97

Optimal Operation of an Industrial Smelter Furnace Off-Gas Cleaning System  

Microsoft Academic Search

Off-gas cleaning systems extract and treat hazardous emissions, and ensure that smelter operations are in accordance with environmental and industrial hygiene regulations. To this end, it is paramount that a well designed control structure be incorporated into the system. We first approach the problem by conducting a steady-state analysis based on a nonlinear model of the process, where the objective

Antonio C. B. Araujo; Romildo P. Brito; Helen Shang

2009-01-01

98

Design and operation of a submerged bed scrubber for off-gas scrubbing  

Microsoft Academic Search

Operation of a submerged bed scrubber has been characterized well enough to accurately estimate the collection efficiency for aerosols in an off-gas treatment system. The device has the advantages of a high degree of reliability and minimal control requirements. Correlations have been developed that allow direct specification of the design variables that are required to achieve a desire collection efficiency.

P. A. Scott; C. M. Ruecker

1986-01-01

99

Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems  

Microsoft Academic Search

Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to

Nick Soelberg; Joe Enneking

2011-01-01

100

Particulate Scrubbing Performance of the High Level Caves Off-Gas System  

SciTech Connect

Performance tests were conducted at the ETF using off-gas from the Small Cylindrical Melter (SCM) -2. The purpose of these tests was to develop data for comparing small and full scale equipment performance. This reports discusses those test results.

Wright, G.T.

2001-08-16

101

Monitoring off-gas O 2\\/CO 2 to predict nitrification performance in activated sludge processes  

Microsoft Academic Search

Nitrification\\/denitrification (NDN) processes are the most widely used technique to remove nitrogenous pollutants from municipal wastewater. The performance of nitrogen removal in the NDN process depends on the metabolism of nitrifying bacteria, and is dependent on adequate oxygen supply. Off-gas testing is a convenient and popular method for measuring oxygen transfer efficiency (OTE) under process conditions and can be performed

Shao-Yuan Leu; Judy A. Libra; Michael K. Stenstrom

2010-01-01

102

Model predictive control of an electric arc furnace off-gas process  

Microsoft Academic Search

This paper shows that an electric arc furnace off-gas system can provide valuable manipulated variables for feedback control which can improve furnace efficiency and contribute to safety in the workplace. Model predictive control (MPC) is used to illustrate this concept using practically motivated control objectives. An initial verification of a non-linear furnace model with plant data is shown. The design

J. G Bekker; I. K Craig; P. C Pistorius

2000-01-01

103

Critique of Hanford Waste Vitrification Plant off-gas sampling requirements  

Microsoft Academic Search

Off-gas sampling and monitoring activities needed to support operations safety, process control, waste form qualification, and environmental protection requirements of the Hanford Waste Vitrification Plant (HWVP) have been evaluated. The locations of necessary sampling sites have been identified on the basis of plant requirements, and the applicability of Defense Waste Processing Facility (DWPF) reference sampling equipment to these HWVP requirements

Goles

1996-01-01

104

Model predictive control of an electric arc furnace off-gas procedure combined with temperature control  

Microsoft Academic Search

Model predictive control (MPC) of an electric arc furnace (EAF) off-gas process combined with temperature control is investigated. A more predictable process, safer working environment, cleaner emission gases and reduced energy wastage are some of the advantages obtained by controlling relative furnace pressure, CO-emission and temperature

D. J. Oosthuizen; I. K. Craig; P. C. Pistorius

1999-01-01

105

Ozonation Dynamics and Its Implication for Off-Gas Ozone Control in Treating Pulp Mill Wastewaters  

Microsoft Academic Search

Ozonation of biologically pretreated pulp mill wastewaters was studied using both bench and pilot scale fine bubble contactors to determine the oxidation efficiencies, mass transfer coefficients (kLa) and enhancement factors (E) due to the occurrence of chemical reactions. A sensitivity analysis based on the measured process parameters was then used to reveal the interrelated effects of key factors on off-gas

Hongde Zhou; Daniel W. Smith

2000-01-01

106

Off-gas treatment system Process Experimental Pilot Plant (PREPP) k-t evaluation  

Microsoft Academic Search

The scope of work for this task involves a systems' evaluation, using the Kepner-Tregoe (K-T) decision analysis methodology, of off-gas treatment alternatives for a Process Experimental Pilot Plant (PREPP). Two basic systems were evaluated: (1) a wet treatment system using a quencher and scrubber system; and (2) a dry treatment system using a spray dryer and baghouse arrangement. Both systems

T. G. Hedahl; C. H. Cargo; A. L. Ayers

1982-01-01

107

Utilization of heat of off-gas from regeneration of cracking catalysts  

Microsoft Academic Search

Shortcomings of boiler-utilizer of the convective type, for the utilization of the physical heat of off-gas, have encouraged the development of the afterburner, a reactor with a fluidized bed of an oxidation catalyst, to replace the boiler-utilizer. Catalysts are investigated and copper chromite or chromium oxide are found sufficient. A test-stand evaluation of the process will precede a full scale

L. I. Golomshtok; A. I. Bogdanov; Y. V. Kolomiitsev; T. M. Levashova; E. A. Levitskii; S. M. Zenkovskii

1983-01-01

108

Iodine129 process control monitor for evaporator off-gas streams  

Microsoft Academic Search

Continuous monitoring of gaseous ¹²⁹I in evaporator off-gas at nuclear fuel reprocessing facilities is important from both regulatory and process control viewpoints. Accordingly, continuous monitoring of evaporator overheads would supply the necessary information to retain ¹²⁹I in the evaporator bottoms should a process control mechanism for the evaporator be developed. Although a continuous ¹²⁹I monitor for nuclear fuel reprocessing plant

J. R. Burr; G. J. McManus

1984-01-01

109

Simplified off-gas analyses in animal cell cultures for process monitoring and control purposes  

Microsoft Academic Search

Batch-to-batch reproducibility of animal cell cultures can significantly be enhanced using process control procedures. Most\\u000a informative signals for advanced process control can be derived from the volume fractions of oxygen and carbon dioxide in\\u000a the vent line of the reactors. Here we employed simple low-cost sensors, previously not considered for off-gas analysis at\\u000a a laboratory-scale cell cultures, and compared them

Mathias Aehle; Artur Kuprijanov; Sebastian Schaepe; Rimvydas Simutis; Andreas Lbbert

110

A dynamic thermal model for heating microalgae incubator ponds using off-gas  

Microsoft Academic Search

Many industrial processes, such as power stations and ore smelters discharge large outflows of waste heat in off-gasses rich in CO2. There is, however, rapidly growing interest in the mitigation of this CO2, including using it to enhance the growth of microalgae for producing biodiesel. The use of off-gas to support ponds that act as microalgae incubators could represent a

H. Shang; J. A. Scott; S. H. Shepherd; G. M. Ross

2010-01-01

111

Proposed method for removal of radioiodine vapor from experiment off-gas system of the ORR  

Microsoft Academic Search

Various methods of removing radio-iodine from air streams were surveyed for possible use in removing radio-iodine accidentally released from reactor experiments into the experiment off-gas system of the ORR. Solid adsorber materials appear to be best suited for this purpose. An iodine decontamination factor of 2000 was experimentally determined for activated charcoal and Linde Molecular Sieve Material (13X) using I¹³¹

R. E. Adams; W. E. Browning

1958-01-01

112

Effects of Headspace and Oxygen Level on Off-gas Emissions from Wood Pellets in Storage  

SciTech Connect

Few papers have been published in the open literature on the emissions from biomass fuels, including wood pellets, during the storage and transportation and their potential health impacts. The purpose of this study is to provide data on the concentrations, emission factors, and emission rate factors of CO2, CO, and CH4 from wood pellets stored with different headspace to container volume ratios with different initial oxygen levels, in order to develop methods to reduce the toxic off-gas emissions and accumulation in storage spaces. Metal containers (45 l, 305 mm diameter by 610 mm long) were used to study the effect of headspace and oxygen levels on the off-gas emissions from wood pellets. Concentrations of CO2, CO, and CH4 in the headspace were measured using a gas chromatograph as a function of storage time. The results showed that the ratio of the headspace ratios and initial oxygen levels in the storage space significantly affected the off-gas emissions from wood pellets stored in a sealed container. Higher peak emission factors and higher emission rates are associated with higher headspace ratios. Lower emissions of CO2 and CO were generated at room temperature under lower oxygen levels, whereas CH4 emission is insensitive to the oxygen level. Replacing oxygen with inert gases in the storage space is thus a potentially effective method to reduce the biomass degradation and toxic off-gas emissions. The proper ventilation of the storage space can also be used to maintain a high oxygen level and low concentrations of toxic off-gassing compounds in the storage space, which is especially useful during the loading and unloading operations to control the hazards associated with the storage and transportation of wood pellets.

Sokhansanj, Shahabaddine [ORNL; Kuang, Xingya [University of British Columbia, Vancouver; Shankar, T.S. [University of British Columbia, Vancouver; Lim, C. Jim [University of British Columbia, Vancouver; Bi, X.T. [University of British Columbia, Vancouver; Melin, Staffan [University of British Columbia, Vancouver

2009-10-01

113

Removal of Mercury from SBW Vitrification Off-Gas by Activated Carbon  

SciTech Connect

Radioactive, acidic waste stored at the Idaho Nuclear Technology and Engineering Center (INTEC) have been previously converted into a dry, granular solid at the New Waste Calcining Facility (NWCF). As an alternative to calcination, direct vitrification of the waste, as well as the calcined solids in an Idaho Waste Vitrification Facility (IWVF) is being considered to prepare the waste for final disposal in a federal repository. The remaining waste to be processed is Sodium-Bearing Waste (SBW). Off-gas monitoring during NWCF operations have indicated that future mercury emissions may exceed the proposed Maximum Achievable Control Technology (MACT) limit of 130 ug/dscm (micrograms/dry standard cubic meter) @ 7% O2 for existing Hazardous Waste Combustors (HWC) if modifications are not made. Carbon monoxide and hydrocarbon emissions may also exceed the MACT limits. Off-gas models have predicted that mercury levels in the off-gas from SBW vitrification will exceed the proposed MACT limit of 45 ug/dscm @ 7% O2 for new HWCs. NO2/44% H2O.

Deldebbio, John Anthony; Watson, T. T.; Kirkham, Robert John

2001-09-01

114

Advanced Off-Gas Control System Design For Radioactive And Mixed Waste Treatment  

SciTech Connect

Treatment of radioactive and mixed wastes is often required to destroy or immobilize hazardous constituents, reduce waste volume, and convert the waste to a form suitable for final disposal. These kinds of treatments usually evolve off-gas. Air emission regulations have become increasingly stringent in recent years. Mixed waste thermal treatment in the United States is now generally regulated under the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. These standards impose unprecedented requirements for operation, monitoring and control, and emissions control. Off-gas control technologies and system designs that were satisfactorily proven in mixed waste operation prior to the implementation of new regulatory standards are in some cases no longer suitable in new mixed waste treatment system designs. Some mixed waste treatment facilities have been shut down rather than have excessively restrictive feed rate limits or facility upgrades to comply with the new standards. New mixed waste treatment facilities in the U. S. are being designed to operate in compliance with the HWC MACT standards. Activities have been underway for the past 10 years at the INL and elsewhere to identify, develop, demonstrate, and design technologies for enabling HWC MACT compliance for mixed waste treatment facilities. Some specific off-gas control technologies and system designs have been identified and tested to show that even the stringent HWC MACT standards can be met, while minimizing treatment facility size and cost.

Nick Soelberg

2005-09-01

115

Theory to boil-off gas cooled shields for cryogenic storage vessels  

NASA Astrophysics Data System (ADS)

An intermediate refrigeration with boil-off gas cooled shields using the boil-off gas stream is an alternative method to the conventional intermediate refrigeration with a cryogenic liquid. By using an analytical calculation method relations are derived, which enable complete predictions about the effectiveness of an intermediate refrigeration with boil-off gas cooled shields as a function of the number of shields for the different stored cryogenic liquids. For this theoretical derivation however, the restrictive assumption must be made that the thermal conductivity of the used insulation material has a constant value between the considered temperature boundaries. For purposes of a more exact calculation a numerical method is therefore suggested, which takes into consideration that the thermal conductivity is temperature-dependent. For a liquid hydrogen storage vessel with a perlite-vacuum insulation e.g., the effectiveness of one shield and its equilibrium temperature are given as a function of the position of the shield in the insulation space.

Hofmann, A.

2004-03-01

116

LIMNOLOGICAL MODELLING: SIMULATION OF VERTICAL PROFILES OF TEMPERATURE, DISSOLVED OXYGEN AND NUTRIENTS. I. THEORY  

Microsoft Academic Search

In a body of water, variations occur in all limnological parameters on many time and space scales. Modelling can either be specific - for a selected subset; or can attempt to simulate the gross characteristics of e.g. current, temperature, algal blooms over an annual cycle (or longer). Vertical profiles perhaps give the greatest information for assessment of water quality. For

B. Henderson-Sellers

1980-01-01

117

Simulation of water temperature and dissolved oxygen distribution in Lake Vegoritis, Greece  

Microsoft Academic Search

Changes in lake water temperature and temperature stratification dynamics can have a profound effect on lake biological and chemical processes. A one-dimensional temperature stratification and oxygen prediction model was developed to simulate the seasonal temperature cycle and oxygen distribution for Lake Vegoritis in Northern Greece. The submodel of heat transport is based on the non-linear heat transfer equation using daily

Vassilis Z Antonopoulos; Soultana K Gianniou

2003-01-01

118

Off-gas chemistry study of melter feed by Springborn Laboratories. [Sludge-only and sludge-precipitate feed samples  

SciTech Connect

The purpose of the off-gas chemistry study of melter feed samples was to support and help substantiate glass melter thermochemistry models developed for the DWPF. Both sludge-only and sludge-precipitate feed samples were analyzed. Each slurry sample was pyrolyzed at temperatures from 150 to 1000/sup 0/C in air and inert atmospheres, and the head space products were analyzed by chromatographic and mass spectrometric methods. Thermogravimetric, differential scanning calorimetric and Fourier transform infrared analyses were also performed on each sample. There were no unusually high exothermic reactions that would be cause for concern in the DWPF melter. Results for two types of sludge-precipitate feed were compared. One type contained simulated precipitate hydrolysis aqueous (PHA) product as fed to the SCM-2 melter. The second type contained PHA from the lab-scale acid hydrolysis reactor in 677-T. A major difference between the two types was a small, but distinct, presence of higher aromatics in gas from feed with reactor-produced PHA. This feed also evolved more CO and CO/sub 2/ than feed with simulated PHA at high pyrolytic temperatures (>750/sup 0/C). Recent analyses have identified the higher boiling aromatics in reactor-produced PHA as primarily diphenylamine and p-terphenyl. These compounds will be included in future PHA simulations that are fed to research melters. Under an inert atmosphere, benzene and phenol were the two most abundant organics evolved during pyrolysis of sludge-precipitate feed.

Crow, K.R.

1985-06-05

119

Formation rate of ammonium nitrate in the off-gas line of SRAT and SME in DWPF  

SciTech Connect

A mathematical model for the formation rate of ammonium nitrate in the off-gas line of the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mixed Evaporator (SME) in DWPF has been developed. The formation rate of ammonium nitrate in the off-gas line depends on pH, temperature, volume and total concentration of ammonia and ammonium ion. Based on a typical SRAT and SME cycle in DWPF, this model predicts the SRAT contributes about 50 lbs of ammonium nitrate while SME contributes about 60 lbs of ammonium nitrate to the off-gas line.

Lee, L.

1992-02-25

120

Recovery Act: Molecular Simulation of Dissolved Inorganic Carbons for Underground Brine CO2 Sequestration  

SciTech Connect

To further our understanding and develop the method for measuring the DICs under geological sequestration conditions, we studied the infrared spectra of DICs under high pressure and temperature conditions. First principles simulations of DICs in brine conditions were performed using a highly optimized ReaxFF-DIC forcefield. The thermodynamics stability of each species were determined using the 2PT method, and shown to be consistent with the Reax simulations. More importantly, we have presented the IR spectra of DIC in real brine conditions as a function of temperature and pressure. At near earth conditions, we find a breaking of the O-C-O bending modes into asymmetric and symmetric modes, separated by 100cm{sup -1} at 400K and 5 GPa. These results can now be used to calibrate FTIR laser measurements.

Goddard, William

2012-11-30

121

Off-gas characteristics of defense waste vitrification using liquid-fed Joule-heated ceramic melters  

Microsoft Academic Search

Off-gas and effluent characterization studies have been established as part of a PNL Liquid-Fed Ceramic Melter development program supporting the Savannah River Laboratory Defense Waste Processing Facility (SRL-DWPF). The objectives of these studies were to characterize the gaseous and airborne emission properties of liquid-fed joule-heated melters as a function of melter operational parameters and feed composition. All areas of off-gas

R. W. Goles; G. J. Sevigny

1983-01-01

122

Simulated long-term temperature and dissolved oxygen characteristics of lakes in the north-central United States and associated fish habitat limits  

Microsoft Academic Search

Water temperatures and dissolved oxygen (DO) concentrations in lakes are related to climate. Temperature and DO in 27 lake classes (3 depth classes x 3 surface area classes x 3 trophic states) were simulated by numerical models with daily weather data input. The weather data used are from the 25-yr period 1955- 1979. The lakes and the weather are representative

H. G. Stefan; J. G. Eaton; J. H. McCormick

1996-01-01

123

Risk ranking of bioaccessible metals from fly ash dissolved in simulated lung and gut fluids  

SciTech Connect

Power plant fly ash from two fuels, coal and a mixture of coal and shredded tires were evaluated for trace metal solubility in simulated human lung and gut fluids (SLF and SGF, respectively) to estimate bioaccessibility. The proportion of bioaccessible to total metal ranged from zero (V) to 80% (Zn) for coal-derived ash in SLF and from 2 (Th) to 100% (Cu) for tire-derived fly ash in SGF. The tire-derived ash contained much more Zn. However, Zn ranked only 5th of the various toxic metals in SGF compared with international regulations for ingestion. On the basis of total concentrations, the metals closest to exceeding limits based on international regulations for inhalation were Cr, Pb, and Al. On dissolution in SLF, the most limiting metals were Pb, Cu, and Zn. For metals exposed to SGF there was no relative change in the top metal, Al, before and after dissolution but the second-ranked metal shifted from Pb to Ni. In most cases only a proportion of the total metal concentrations in either fly ash was soluble, and hence bioaccessible, in either biofluid. When considering the regulatory limits for inhalation of particulates, none of the metal concentrations measured were as hazardous as the fly ash particulates themselves. However, on the basis of the international ingestion regulations for Al, the maximum mass of fly ash that could be ingested is only 1 mg per day (10 mg based on bioaccessibility). It is possible that such a small mass could be consumed by exposed individuals or groups. 39 refs., 1 fig., 3 tabs.

John Twining; Peter McGlinn; Elaine Loi; Kath Smith; Reto Giere [Australian Nuclear Science and Technology Organisation, Menai, NSW (Australia)

2005-10-01

124

CHARACTERIZATION OF DWPF MELTER OFF-GAS QUENCHER AND STEAM ATOMIZED SCRUBBER DEPOSIT SAMPLES  

SciTech Connect

This report summarizes the results from the characterization of deposits from the inlets of the primary off-gas Quencher and Steam Atomized Scrubber (SAS) in the Defense Waste Processing Facility (DWPF), as requested by a technical assistance request. DWPF requested elemental analysis and compound identification to help determine the potential causes for the substance formation. This information will be fed into Savannah River National Laboratory modeling programs to determine if there is a way to decrease the formation of the deposits. The general approach to the characterization of these samples included x-ray diffraction (XRD), scanning electron microscopy (SEM), and chemical analysis. The following conclusions are drawn from the analytical results found in this report: (1) The deposits are not high level waste glass from the DWPF melt pool based on comparison of the compositions of deposits to the composition of a sample of glass taken from the pour stream of the melter during processing of Sludge Batch 3. (2) Chemical composition results suggest that the deposits are probably a combination of sludge and frit particles entrained in the off-gas. (3) Gamma emitters, such as Co-60, Cs-137, Eu-154, Am-241, and Am-243 were detected in both the Quencher and SAS samples with Cs-137 having the highest concentration of the gamma emitters. (4) No evidence existed for accumulation of fissile material (U-233, U-235, and Pu-239) relative to Fe in either deposit. (5) XRD results indicated both samples were primarily amorphorous and contained some crystals of the iron oxides, hematite and magnetite (Fe{sub 2}O{sub 3} and Fe(Fe{sub 2}O{sub 4})), along with sodium nitrate (NaNO{sub 3}). The other main crystalline compound in the SAS deposit was mercurous chloride. The main crystalline compound in the Quencher deposit was a uranium oxide compound. These are all sludge components. (6) SEM analysis of the Quencher deposit revealed crystalline uranium compounds within the sample. SEM analysis of the SAS sample could not be performed due to the presence of a significant concentration of Hg in the sample. (7) Essentially all the Na and the S in the off-gas samples were soluble in water. (8) The main soluble anion was NO{sub 3}{sup -} with SO{sub 4}{sup 2-} being second. (9) In contrast to the results for the off-gas deposits analyzed in 2003, soluble compounds of fluoride and chloride were detected; however, their concentrations in the Quencher and SAS deposits were less than one weight percent. (10) The results suggest that the S is primarily in the deposits as the sulfate anion.

Zeigler, K; Ned Bibler, N

2007-06-06

125

Critique of Hanford Waste Vitrification Plant off-gas sampling requirements  

SciTech Connect

Off-gas sampling and monitoring activities needed to support operations safety, process control, waste form qualification, and environmental protection requirements of the Hanford Waste Vitrification Plant (HWVP) have been evaluated. The locations of necessary sampling sites have been identified on the basis of plant requirements, and the applicability of Defense Waste Processing Facility (DWPF) reference sampling equipment to these HWVP requirements has been assessed for all sampling sites. Equipment deficiencies, if present, have been described and the bases for modifications and/or alternative approaches have been developed.

Goles, R.W.

1996-03-01

126

Fish Individual-based Numerical Simulator (FINS): A particle-based model of juvenile salmonid movement and dissolved gas exposure history in the Columbia River Basin  

SciTech Connect

This paper describes a numerical model of juvenile salmonid migration in the Columbia and Snake Rivers. The model, called the Fish Individual-based Numerical Simulator or FINS, employs a discrete, particle-based approach to simulate the migration and history of exposure to dissolved gases of individual fish. FINS is linked to a two-dimensional (vertically-averaged) hydrodynamic simulator that quantifies local water velocity, temperature, and dissolved gas levels as a function of river flow rates and dam operations. Simulated gas exposure histories can be input to biological mortality models to predict the effects of various river configurations on fish injury and mortality due to dissolved gas supersaturation. Therefore, FINS serves as a critical linkage between hydrodynamic models of the river system and models of biological impacts. FINS was parameterized and validated based on observations of individual fish movements collected using radiotelemetry methods during 1997 and 1998. A quasi-inverse approach was used to decouple fish swimming movements from advection with the local water velocity, allowing inference of time series of non-advective displacements of individual fish from the radiotelemetry data. Statistical analyses of these displacements are presented, and confirm that strong temporal correlation of fish swimming behavior persists in some cases over several hours. A correlated random-walk model was employed to simulate the observed migration behavior, and parameters of the model were estimated that lead to close correspondence between predictions and observations.

Scheibe, Timothy D.; Richmond, Marshall C.

2002-01-30

127

Microbial community evolution during simulated managed aquifer recharge in response to different biodegradable dissolved organic carbon (BDOC) concentrations.  

PubMed

This study investigates the evolution of the microbial community in laboratory-scale soil columns simulating the infiltration zone of managed aquifer recharge (MAR) systems and analogous natural aquifer sediment ecosystems. Parallel systems were supplemented with either moderate (1.1mg/L) or low (0.5mg/L) biodegradable dissolved organic carbon (BDOC) for a period of six months during which time, spatial (1cm, 30cm, 60cm, 90cm, and 120cm) and temporal (monthly) analyses of sediment-associated microbial community structure were analyzed. Total microbial biomass associated with sediments was positively correlated with BDOC concentration where a significant decline in BDOC was observed along the column length. Analysis of 16S rRNA genes indicated dominance by Bacteria with Archaea comprising less than 1 percent of the total community. Proteobacteria was found to be the major phylum in samples from all column depths with contributions from Betaproteobacteria, Alphaproteobacteria and Gammaproteobacteria. Microbial community structure at all the phylum, class and genus levels differed significantly at 1cm between columns receiving moderate and low BDOC concentrations; in contrast strong similarities were observed both between parallel column systems and across samples from 30 to 120cm depths. Samples from 1cm depth of the low BDOC columns exhibited higher microbial diversity (expressed as Shannon Index) than those at 1cm of moderate BDOC columns, and both increased from 5.4 to 5.9 at 1cm depth to 6.7-8.3 at 30-120cm depths. The microbial community structure reached steady state after 3-4 months since the initiation of the experiment, which also resulted in an improved DOC removal during the same time period. This study suggested that BDOC could significantly influence microbial community structure regarding both composition and diversity of artificial MAR systems and analogous natural aquifer sediment ecosystems. PMID:23490107

Li, Dong; Alidina, Mazahirali; Ouf, Mohamed; Sharp, Jonathan O; Saikaly, Pascal; Drewes, Jrg E

2013-02-26

128

CALCULATION OF DEMONSTRATION BULK VITRIFICATION SYSTEM MELTER INLEAKAGE AND OFF-GAS GENERATION RATE  

SciTech Connect

The River Protection Project (RPP) mission is to safely store, retrieve, treat, immobilize, and dispose of the Hanford Site tank waste. The Demonstration Bulk Vitrification System (DBVS) is a research and development project whose objective is to demonstrate the suitability of Bulk Vitrification treatment technology waste form for disposing of low-activity waste from the Tank Farms. The objective of this calculation is to determine the DBVS melter inleakage and off-gas generation rate based on full scale testing data from 38D. This calculation estimates the DBVS melter in leakage and gas generation rate based on test data. Inleakage is estimated before the melt was initiated, at one point during the melt, and at the end of the melt. Maximum gas generation rate is also estimated.

MAY TH

2008-04-16

129

Simplified off-gas analyses in animal cell cultures for process monitoring and control purposes.  

PubMed

Batch-to-batch reproducibility of animal cell cultures can significantly be enhanced using process control procedures. Most informative signals for advanced process control can be derived from the volume fractions of oxygen and carbon dioxide in the vent line of the reactors. Here we employed simple low-cost sensors, previously not considered for off-gas analysis at a laboratory-scale cell cultures, and compared them with a simultaneously used quadrupole mass spectrometer, i.e., the standard equipment. A decisive advantage is that the sensors did not need any calibration and are easy to use. We show that monitoring and advanced control of cell cultures can significantly be simplified using the devices tested here and that the same batch-to-batch reproducibility can be obtained with much less effort than before. PMID:21744145

Aehle, Mathias; Kuprijanov, Artur; Schaepe, Sebastian; Simutis, Rimvydas; Lbbert, Andreas

2011-07-09

130

Fabrication of remote steam atomized scrubbers for DDWPF (Defense Waste Processing Facility) off-gas system  

SciTech Connect

The Defense Waste Processing Facility (DWPF) is being constructed for the purpose of processing high-level waste from liquid sludge to a vitrified borosilicate glass. In the operation of continuous slurry-fed melters, off-gas aerosols are created by entrainment of feed slurried and the vaporization of volatile species from the molten glass mixture. It is necessary to decontaminate these aerosols in order to minimize discharge of airborne radionuclide particulates. A Steam Atomized Scrubber (SAS) has been developed for DWPF which utilizes a patented Hydro-Sonic System gas scrubbing method. The Hydro-Sonic System utilizes a steam aspirating-type venturi scrubber that requires very precise fabrication tolerances in order to obtain acceptable decontamination factors. In addition to the process-related tolerances, precision mounting and nozzle tolerances are required for remote service at DWPF.

Nielsen, M.G.; Lafferty, J.D.

1988-01-01

131

Nitrous oxide monitoring for nitrifying activated sludge aeration control: a simulation study.  

PubMed

An activated sludge aeration control concept was developed utilizing off-gas nitrous oxide concentrations as a surrogate for autotrophic nitrifying bacterial inhibition and aeration air as a master control variable. The control concept was evaluated using a simulated pilot scale bioreactor (mathematically calibrated liquid phase process model and a model to link off-gas nitrous oxide generation to liquid phase conditions) as a data generator. When applied to the simulated system, the process controller was successful at maintaining the process at the desired operating setpoint and promoting stable operation by minimizing periods of significant inhibition. Furthermore, it provided a more efficient use of the air supplied to the bioreactor during periods of varying feed loading by matching the air supply to the metabolic demands, substantially reducing periods of over and under-aeration. The findings of this research demonstrate the potential for off-gas nitrous oxide monitoring as a completely non-invasive alternative to liquid phase monitoring used in conventional dissolved oxygen control. Investigations are currently underway at the laboratory scale to evaluate the benefits and limitations associated with this control concept, with particular emphasis on implementation issues and the quantification of potential aeration and cost savings. PMID:18454495

Sivret, Eric C; Peirson, William L; Stuetz, Richard M

2008-09-01

132

Simulated effects of the proposed Garrison Diversion Unit on streamflow and dissolved solids in the Sheyenne River and the Red River of the North, North Dakota and Minnesota  

USGS Publications Warehouse

Future development of the Garrison Diversion Unit in North Dakota could deliver 100 cubic feet per second of water for the cities of Fargo, Grand Forks, and surrounding communities. Missouri River water from the Garrison Diversion Unit Sheyenne River water supply would be delivered to the upper reaches of the Sheyenne River, which would convey the water to the Red River of the North. Potential effects of releasing Missouri River water to the Sheyenne River on the quantity and quality of streamflow in the Sheyenne River and in the Red River of the North are evaluated for two proposed operating plans--year-round operation (12 months each year) and nonwinter operation (April through October each year). The Project Canals, Reservoirs, and River Systems (PROCRRS) and Canals, Rivers, and Reservoirs Salinity Accounting Procedures (CRRSAP) monthly accounting models are used to predict streamflow and dissolved-solids changes that could result from the proposed release of treated Missouri River water into the Sheyenne River and the Red River of the North. For year-round operation of the Garrison Diversion Unit Sheyenne River water supply for the period 1931-84, the maximum quantity of water that must be delivered to the upper reaches of the Sheyenne River so that 100 cubic feet per second of Missouri River water can be delivered to Fargo, N.Dak., and Grand Forks, N.Dak., was estimated to be about 151 cubic feet per second for August 1976. For nonwinter operation the maximum quantity of water was estimated to be about 210 cubic feet per second. Model simulations were used to assess the effects that operation of the Garrison Diversion Unit Sheyenne River water supply could have on streamflow and water quality of the Sheyenne River and the Red River of the North. Effects were assessed by comparing simulated streamflows that include Missouri River water to baseline conditions, which represent hydrologic conditions before addition of Missouri River water. Simulated mean monthly dissolved-solids concentrations for Sheyenne River nodes for year-round and nonwinter operation of the Garrison Diversion Unit Sheyenne River water supply generally were less than those for baseline conditions.Simulated mean monthly dissolved-solids concentrations for Red River of the North nodes for year-round and nonwinter operation generally were greater than those for baseline conditions. Streamflow for 1933-42 was about 25 percent of the mean annual streamflow for 1931-84. Simulated monthly mean dissolved-solids concentrations for year-round and nonwinter operation for node 125, Sheyenne River near Cooperstown, N.Dak., for the low-flow conditions of 1933-42 were less than those for baseline conditions. Annual variability of simulated dissolved-solids concentrations for year-round operation was less than annual variability for nonwinter operation and for baseline conditions. Simulated monthly mean dissolved-solids concentrations for year-round and nonwinter operation for node 250, Sheyenne River near Kindred, N.Dak., for the low-flow conditions of 1933-42 ranged from 500 to 600 milligrams per liter.Simulated monthly mean dissolved-solids concentrations for baseline conditions ranged from 300 milligrams per liter to greater than 1,000 milligrams per liter. Simulated monthly mean dissolved-solids concentrations for nonwinter operation were less than those for year-round operation. For node 700, Red River of the North at Grand Forks, N.Dak., the magnitude of simulated monthly mean dissolved-solids concentrations for year-round and nonwinter operation for the low-flow conditions of 1933-42 were about the same as those for baseline conditions. Streamflow for 1973-82 was about 30 percent greater than the mean annual streamflow for 1931-84. For the high-flow conditions of 1973-82, simulated monthly mean dissolved-solids concentrations for node 125 for year-round operation ranged from about 325 to 650 milligrams per liter, and simulated monthly mean dissolved-solids c

Guenthner, R. Scott

1993-01-01

133

Final Report on Testing of Off-Gas Treatment Technologies for Abatement of Atmospheric Emissions of Chlorinated Volatile Organic Compounds  

SciTech Connect

The purpose of this report is to summarize the results of the program for off-gas treatment of atmospheric emissions of chlorinated volatile organic compounds (CVOCs), in particular trichloroethylene (TCE) and perchloroethylene (PCE). This program was funded through the Department of Energy Office of Technology Development`s VOC`s in Non-Arid Soils Integrated Demonstration (VNID). The off-gas treatment program was initiated after testing of in-situ air stripping with horizontal wells was completed (Looney et al., 1991). That successful test expectedly produced atmospheric emissions of CVOCs that were unabated. It was decided after that test that an off-gas treatment is an integral portion of remediation of CVOC contamination in groundwater and soil but also because several technologies were being developed across the United States to mitigate CVOC emissions. A single platform for testing off-gas treatment technologies would facilitate cost effective evaluation of the emerging technologies. Another motivation for the program is that many CVOCs will be regulated under the Clean Air Act Amendments of 1990 and are already regulated by many state regulatory programs. Additionally, compounds such as TCE and PCE are pervasive subsurface environmental contaminants, and, as a result, a small improvement in terms of abatement efficiency or cost will significantly reduce CVOC discharges to the environment as well as costs to United States government and industry.

Jarosch, T.R.; Haselow, J.S.; Rossabi, J.; Burdick, S.A.; Raymond, R.; Young, J.E.; Lombard, K.H.

1995-01-23

134

Airborne waste management technology applicable for use in reprocessing plants for control of iodine and other off-gas constituents  

Microsoft Academic Search

Extensive work in the area of iodine removal from reprocessing plant off-gas streams using various types of solid sorbent materials has been conducted worldwide over the past two decades. This work has focused on the use of carbon filters, primarily for power plant applications. More recently, the use of silver-containing sorbents has been the subject of considerable research. The most

Jubin

1988-01-01

135

MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM - PRELIMINARY REPORT  

SciTech Connect

The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that come in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter off-gas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, Cl, Cl{sub 2}, and chloride salts in the melter vapor space. The values for these parameters were determined at two different melter vapor space temperatures by matching the calculated molar ratio of HgCl (or Hg{sub 2}Cl{sub 2}) to HgCl{sub 2} with those measured during the Experimental-Scale Ceramic Melter (ESCM) tests run at the Pacific Northwest National Laboratory (PNNL). The calibrated model was then applied to the SB5 simulant used in the earlier flowsheet study with an assumed mercury stripping efficiency of zero; the molar ratio of Cl-to-Hg in the resulting melter feed was only 0.4, compared to 12 for the ESCM feeds. The results of the model run at the indicated melter vapor space temperature of 650 C (TI4085D) showed that due to excessive shortage of chloride, only 6% of the mercury fed is expected to get oxidized, mostly as HgCl, while the remaining mercury would exist either as elemental mercury vapor (90%) or HgO (4%). Noting that the measured chloride level in the SB5 qualification sample was an order of magnitude lower than that used in the SB5 simulant, the degree of chloride shortage will be even greater. As a result, the projected level of HgCl in the actual SB5 melter exhaust will be even lower than 6% of the total mercury fed, while that of elemental mercury is likely to be greater than 90%. The homogeneous oxidation of mercury in the off-gas was deemed to be of primary importance based on the postulation that mercury and other volatile salts form submicron sized aerosols upon condensation and thus remain largely in the gas stream downstream of the quencher where they can deposit in the off-gas lines, Steam-Atomized Scrubbers (SAS), and High-Efficiency Mist Eliminator (HEME). Formation of these submicron semi-volatile salts in the condensate liquid is considered to be unlikely, so the liquid phase reactions were considered to be less important. However, subsequent oxidation of mercury in the liquid phase in the off-gas system was examined in a simplified model of the off-gas condensate. It was found that the condensate chemistry was consistent with further oxidation of elemental mercury to Hg{sub 2}Cl{sub 2} and conversion of HgO to chlorides. The results were consistent with the available experimental data. It should also be noted that the model predictions presented in this report do not include any physically entrained solids, which typically account for much of the off-gas carryover on a mass basis. The high elemental mercury vapor content predicted at the DWPF Quencher inlet means that physically entrained solids could provide the necessary surface onto which elemental mercury vapor could condense, thereby coating the solids as well as the internal surfaces of the off-gas system with mercury. Clearly, there are many process benefits to be gained by removing the steam-stripping step from the CPC c

Zamecnik, J.; Choi, A.

2009-03-25

136

Technology status report: Off-gas treatment technologies for chlorinated volatile organic compound air emissions  

SciTech Connect

The purpose of this document is to review technologies for treatment of air streams that contain chlorinated volatile organic compounds (CVOCS) and to describe a Department of Energy Office of Technology Development program that is planned to demonstrate innovative technologies for the abatement of CVOC emissions. This report describes the first phase of testing of off-gas treatment technologies. At least one more phase of testing is planned. Guidance for the preparation of this document was provided by a predecisional draft outline issued by the Department of Energy`s Office of Technology Development. The report is intended to evaluate the technical and regulatory aspects, public acceptance, and estimated costs of technologies selected for development and testing. These technologies are compared to currently practiced or baseline methods for treatment of CVOC-laden airstreams. A brief overview is provided rather than detailed cost and data comparisons because many of these technologies have not yet been field tested. A description of other promising technologies for the treatment of CVOC emissions is also included. Trichloroethylene (TCE) and perchloroethylene (PCE) were used for industrial cleaning and solvent applications for several decades. These chemicals can be classified as CVOCS. As a result of past standard disposal practices, these types of compounds are persistent groundwater and soil contaminants throughout the United States and the Department of Energy Complex.

Rossabi, J.; Haselow, J.S.

1992-04-15

137

Technology status report: Off-gas treatment technologies for chlorinated volatile organic compound air emissions  

SciTech Connect

The purpose of this document is to review technologies for treatment of air streams that contain chlorinated volatile organic compounds (CVOCS) and to describe a Department of Energy Office of Technology Development program that is planned to demonstrate innovative technologies for the abatement of CVOC emissions. This report describes the first phase of testing of off-gas treatment technologies. At least one more phase of testing is planned. Guidance for the preparation of this document was provided by a predecisional draft outline issued by the Department of Energy's Office of Technology Development. The report is intended to evaluate the technical and regulatory aspects, public acceptance, and estimated costs of technologies selected for development and testing. These technologies are compared to currently practiced or baseline methods for treatment of CVOC-laden airstreams. A brief overview is provided rather than detailed cost and data comparisons because many of these technologies have not yet been field tested. A description of other promising technologies for the treatment of CVOC emissions is also included. Trichloroethylene (TCE) and perchloroethylene (PCE) were used for industrial cleaning and solvent applications for several decades. These chemicals can be classified as CVOCS. As a result of past standard disposal practices, these types of compounds are persistent groundwater and soil contaminants throughout the United States and the Department of Energy Complex.

Rossabi, J.; Haselow, J.S.

1992-04-15

138

Release model for in situ vitrification large-field test off-gas treatment system  

SciTech Connect

A conceptual model for the vapor and aerosol transport and deposition in the in situ vitrification large-field test off-gas system (OGS) has been developed. This model can be used to predict the emissions from the OGS under normal and off-normal conditions. Results generated by the model can be used to evaluate design and/or procedural modifications, define tests, and predict results. The OGS vapor and aerosol transport and deposition is modeled using the PULSE/MOD-ISV/VER 1.0.0 developmental computer code. Input data requirements for this code include the specific geometries of the OGS components; the composition, rate, and temperature of the vapors and aerosols entering the OGS; and the OGS component surface temperatures or heat fluxes. Currently, not all of these model inputs are available. Therefore, conceptual input parameters are developed. Using this input data, preliminary calculations with the code have been performed. These calculations include a demonstration that the code predicts convergent results, a comparison of predicted results with performance data for one of the OGS components, and a preliminary sensitivity study of the complete model.

Pafford, D.J.; Tung, V.X.

1992-03-01

139

Distributions of 14 elements into 10 liquid extractants from simulated acid-dissolved sludge and acidified supernate solutions of Hanford high-level waste  

Microsoft Academic Search

The distributions of 14 elements into ten extractants were measured from simulant solutions that represent acidic dissolved sludge and acidified supernate from Hanford HLW Tank 102-SY. The extractants: LIX{sup TM}-26, LIX{sup TM}-54, LIX{sup TM}-84, LIX{sup TM}-1010, Cyanex{sup TM} 272, Cyanex{sup TM} 923, Aliquat{sup TM} 336, DHDECMP, DHDECMP-DIPB, and CMPO-DIPB, were sorbed on porous carbon beads to provide dry-appearing beads that

S. F. Marsh; Z. V. Svitra; S. M. Bowen

1994-01-01

140

MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM-PRELIMINARY REPORT  

SciTech Connect

The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that comes in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter offgas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, Cl, Cl{sub 2}, and chloride salts in the melter vapor space. The values for these parameters were determined at two different melter vapor space temperatures by matching the calculated molar ratio of HgCl (or Hg{sub 2}Cl{sub 2}) to HgCl{sub 2} with those measured during the Experimental-Scale Ceramic Melter (ESCM) tests run at the Pacific Northwest National Laboratory (PNNL). The calibrated model was then applied to the SB5 simulant used in the earlier flowsheet study with an assumed mercury stripping efficiency of zero; the molar ratio of Cl-to-Hg in the resulting melter feed was only 0.4, compared to 12 for the ESCM feeds. The results of the model run at the indicated melter vapor space temperature of 650 C (TI4085D) showed that due to excessive shortage of chloride, only 6% of the mercury fed is expected to get oxidized, mostly as HgCl, while the remaining mercury would exist either as elemental mercury vapor (90%) or HgO (4%). Noting that the measured chloride level in the SB5 qualification sample was an order of magnitude lower than that used in the SB5 simulant, the degree of chloride shortage will be even greater. As a result, the projected level of HgCl in the actual SB5 melter exhaust will be even lower than 6% of the total mercury fed, while that of elemental mercury is likely to be greater than 90%. The homogeneous oxidation of mercury in the off-gas was deemed to be of primary importance based on the postulation that mercury and other volatile salts form submicron sized aerosols upon condensation and thus remain largely in the gas stream downstream of the quencher where they can deposit in the off-gas lines, Steam-Atomized Scrubbers (SAS), and High-Efficiency Mist Eliminator (HEME). Formation of these submicron semi-volatile salts in the condensate liquid is considered to be unlikely, so the liquid phase reactions were considered to be less important. However, subsequent oxidation of mercury in the liquid phase in the off-gas system was examined in a simplified model of the off-gas condensate. It was found that the condensate chemistry was consistent with further oxidation of elemental mercury to Hg{sub 2}Cl{sub 2} and conversion of HgO to chlorides. The results were consistent with the available experimental data. It should also be noted that the model predictions presented in this report do not include any physically entrained solids, which typically account for much of the off-gas carryover on a mass basis. The high elemental mercury vapor content predicted at the DWPF Quencher inlet means that physically entrained solids could provide the necessary surface onto which elemental mercury vapor could condense, thereby coating the solids as well as the internal surfaces of the off-gas system with mercury. Clearly, there are many process benefits to be gained by removing the steam-stripping step from the CPC c

Zamecnik, J.; Choi, A.

2010-08-18

141

Modeling of off-gas emissions from wood pellets during marine transportation.  

PubMed

After a fatal accident during the discharge of wood pellets at Helsingborg, emissions from pellets during marine transportation became a concern for the safe handling and storage of wood pellets. In this paper, a two-compartment model has been developed for the first time to predict the concentrations of CO, CO?, CH?, and O? inside the cargo ship and the time and rate of forced ventilation required before the safe entry into the stairway adjacent to the storage hatch. The hatch and stairway are treated as two perfectly mixed tanks. The gas exchange rate between these two rooms and the gas exchange rate with the atmosphere are fitted to satisfy a measured tracer final concentration of 33 p.p.m.v. in the stairway and an average final hatch to stairway CO, CO?, and CH? concentration ratio of 1.62 based on measurement from five other hatch and stairway systems. The reaction kinetics obtained from a laboratory unit using a different batch of pellets, however, need to be scaled in order to bring the prediction to close agreement with onboard measured emission data at the end of voyage. Using the adjusted kinetic data, the model was able to predict the general trend of data recorded in the first 12.5 days of the voyage. Further validation, however, requires the data recorded over the whole journey. The model was applied to predict the effect of ocean temperature on the off-gas emissions and the buildup of concentrations in the hatch and stairway. For safe entry to the cargo ship, the current model predicted that a minimal ventilation rate of 4.4 hr? is required for the stairway's CO concentration to lower to a safe concentration of 25 p.p.m.v. At 4.4 hr?, 10 min of ventilation time is required for the safe entry into the stairway studied. PMID:20603277

Pa, Ann; Bi, Xiaotao T

2010-07-05

142

Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems  

SciTech Connect

Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absoption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

Nick Soelberg; Joe Enneking

2011-05-01

143

Systematic selection of off-gas treatment at the Savannah River Site  

SciTech Connect

At the Savannah River Site (SRS), from 1958--1985, effluent waste from the reactor fuel and target rod fabrication area (M-Area) was discharged to a settling basin. In 1981, monitoring wells detected groundwater contamination, specifically trichloroethylene and tetrachloroethylene, in the immediate vicinity of the basin. Under the auspices of Resource Conservation and Recovery Act (RCRA) the M-Area contamination must be addressed by a corrective action program until the volatile organic compound (VOC) concentrations reach Drinking Water Standards. This was initiated in 1985 with startup of a full-scale pump-and-treat air stripper system. Recently, remediation efforts have focused on vacuum extraction to treat vadose zone contamination not addressed by the original recovery wells, and additional pump-and-treat systems to achieve hydraulic control of the plume. Regulatory requirements allowed for discharge of VOCs to the atmosphere when the original remediation system was installed; however, 1990 amendments to the Clean Air Act will eventually require treatment of VOC contaminated air prior to discharge. This has ramifications to systems currently being design, as well as the existing systems. In response to the 1990 Clean Air Act amendments, SRS initiated a study to assess commercially available off-gas treatment technologies. These included carbon adsorption, thermal incineration, catalytic oxidation, absorption, condensation, and UV/peroxide destruction, and xenon flashlamp. Criteria used to evaluate the technologies were the thirty (30) year life cycle cost, permitting considerations, and manpower requirements. The study concluded that catalytic oxidation provided the most desirable combination of these elements.

McKillip, S.T.; Rehder, T.E.

1992-01-01

144

New wste calcining facility process off-gas filtration system and remote in-place DOP test  

Microsoft Academic Search

The crabtrap, one component of a remotely-operable, experimental, in-place DOP test system for process off-gas HEPA filters being developed at Flanders Filters was tested with good results. The crabtrap is a device which is positioned downstream of a HEPA filter during in-place DOP testing to thoroughly mix and collect the air and DOP passing through the filter so the efficiency

H. H. Loo; R. R. Smith; G. E. Bingham; T. T. Allan; D. E. Wilcox

1978-01-01

145

Investigation of the combined adsorption of krypton, xenon, and water vapor of the off-gas of atomic power stations  

Microsoft Academic Search

A radiochromatogra phic system of purifying the off-gas from the short-lived krypton, xenon, and iodine nuclides is presently used in Russian atomic power stations and in foreign atomic power stations equipped with the aid of the USSR. The basic elements of the system are filter-adsorbers filled with activated carbon and a drying unit [1-3]. Dynamic adsorption and radioactive decay in

I. E. Nakhutin; D. V. Ochkin; S. A. Tret'yak

1980-01-01

146

Comparison of the efficiency of large-scale ceramic and membrane aeration systems with the dynamic off-gas method  

Microsoft Academic Search

The aeration systems of two full-scale activated sludge basins were compared over 2.5 years under the same operating conditions using dynamic off-gas testing. Only the material of the diffuser was different, membrane vs. ceramic tube diffusers. The experimental design took the complexity and dynamics of the system into consideration. The investigation has shown that, although the membrane diffusers have higher

J. A. Libra; A. Schuchardt; C. Sahlmann; J. Handschag; U. Wiesmann; R. Gnirss

147

Structure-property relationship of metal-organic frameworks (MOFs) and physisorbed off-gas radionuclides.  

SciTech Connect

We report on the host-guest interactions between metal-organic frameworks (MOFs) with various profiles and highly polarizable molecules (iodine), with emphasis on identifying preferential sorption sites in these systems. Radioactive iodine 129I, along with other volatile radionuclides (3H, 14C, Xe and Kr), represents a relevant component in the off-gas resulted during nuclear fuel reprocessing. Due to its very long half-life, 15.7 x 106 years, and potential health risks in humans, its efficient capture and long-term storage is of great importance. The leading iodine capture technology to date is based on trapping iodine in silver-exchanged mordenite. Our interests are directed towards improving existent capturing technologies, along with developing novel materials and alternative waste forms. Herein we report the first study that systematically monitors iodine loading onto MOFs, an emerging new class of porous solid-state materials. In this context, MOFs are of particular interest as: (i) they serve as ideal high capacity storage media, (ii) they hold potential for the selective adsorption from complex streams, due to their high versatility and tunability. This work highlights studies on both newly developed in our lab, and known highly porous MOFs that all possess distinct characteristics (specific surface area, pore volume, pore size, and dimension of the window access to the pore). The materials were loaded to saturation, where elemental iodine was introduced from solution, as well as from vapor phase. Uptakes in the range of {approx}125-150 wt% I2 sorbed were achieved, indicating that these materials outperform all other solid adsorbents to date in terms of overall capacity. Additionally, the loaded materials can be efficiently encapsulated in stable waste forms, including as low temperature sintering glasses. Ongoing studies are focused on gathering qualitative information with respect to localizing the physisorbed iodine molecules within the frameworks: X-ray single-crystal analyses, in conjunction with high pressure differential pair distribution function (d-PDF) studies aimed to identify preferential sites in the pores, and improve MOFs robustness. Furthermore, durability studies on the iodine loaded MOFs and subsequent waste forms include thermal analyses, SEM/EDS elemental mapping, and leach-durability testing. We anticipate for this in-depth analysis to further aid the design of advanced materials, capable to address major hallmarks: safe capture, stability and durability over extended timeframes.

Nenoff, Tina Maria; Chupas, Peter J. (Argonne National Laboratory); Garino, Terry J.; Rodriguez, Mark Andrew; Chapman, Karena W. (Argonne National Laboratory); Sava, Dorina Florentina

2010-11-01

148

FLOWSHEET EVALUATION FOR THE DISSOLVING AND NEUTRALIZATION OF SODIUM REACTOR EXPERIMENT USED NUCLEAR FUEL  

SciTech Connect

This report includes the literature review, hydrogen off-gas calculations, and hydrogen generation tests to determine that H-Canyon can safely dissolve the Sodium Reactor Experiment (SRE; thorium fuel), Ford Nuclear Reactor (FNR; aluminum alloy fuel), and Denmark Reactor (DR-3; silicide fuel, aluminum alloy fuel, and aluminum oxide fuel) assemblies in the L-Bundles with respect to the hydrogen levels in the projected peak off-gas rates. This is provided that the number of L-Bundles charged to the dissolver is controlled. Examination of SRE dissolution for potential issues has aided in predicting the optimal batching scenario. The calculations detailed in this report demonstrate that the FNR, SRE, and DR-3 used nuclear fuel (UNF) are bounded by MURR UNF and may be charged using the controls outlined for MURR dissolution in a prior report.

Daniel, W. E.; Hansen, E. K.; Shehee, T. C.

2012-10-30

149

Process system evaluation-consolidated letters. Volume 1. Alternatives for the off-gas treatment system for the low-level waste vitrification process  

Microsoft Academic Search

This report provides an evaluation of alternatives for treating off-gas from the low-level waste (LLW) melter. The study used expertise obtained from the commercial nonradioactive off-gas treatment industry. It was assumed that contact maintenance is possible, although the subsequent risk to maintenance personnel was qualitatively considered in selecting equipment. Some adaptations to the alternatives described may be required, depending on

L. M. Peurrung; T. J Deforest; J. R. Richards

1996-01-01

150

Simulating unsteady transport of nitrogen, biochemical oxygen demand, and dissolved oxygen in the Chattahoochee River downstream from Atlanta, Georgia  

USGS Publications Warehouse

As part of an intensive water-quality assessment of the Chattahoochee River, repetitive water-quality measurements were made at 12 sites along a 69-kilometer reach of the river downstream of Atlanta, Georgia. Concentrations of seven constituents (temperature, dissolved oxygen, ultimate carbonaceous biochemical oxygen demand (BOD), organic nitrogen, ammonia, nitrite, and nitrate) were obtained during two periods of 36 hours, one starting on August 30, 1976, and the other starting on May 31, 1977. The study reach contains one large and several small sewage outfalls and receives the cooling water from two large powerplants. An unsteady water-quality model of the Lagrangian type was calibrated using the 1977 data and verified using the 1976 data. The model provided a good means of interpreting these data even though both the flow and the pollution loading rates were highly unsteady. A kinetic model of the cascade type accurately described the physical and biochemical processes occurring in the river. All rate coefficients, except reaeration coefficients and those describing the resuspension of BOD, were fitted to the 1977 data and verified using the 1976 data. The study showed that, at steady low flow, about 38 percent of the BOD settled without exerting an oxygen demand. At high flow, this settled BOD was resuspended and exerted an immediate oxygen demand. About 70 percent of the ammonia extracted from the water column was converted to nitrite, but the fate of the remaining 30 percent is unknown. Photosynthetic production was not an important factor in the oxygen balance during either run.

Jobson, Harvey E.

1985-01-01

151

Dissolved Oxygen and Temperature  

Microsoft Academic Search

Dissolved oxygen and temperature are two of the fundamental variables in lake and pond ecology. By measuring dissolved oxygen and temperature, scientists can gauge the overall condition of waterbodies. Aquatic organisms need dissolved oxygen for their survival. While water temperature also directly influences aquatic organ- isms, it regulates dissolved oxygen concentrations within a lake. Dissolved oxygen and temperature are also

Kelly Addy; Linda Green

152

Simulations of Dissolved and Particulate Organic Matter with a Nitrogen-based Oceanic Ecosystem Model: A one Dimensional Model Applied to the Hawaii Ocean Time-series Station ALOHA  

NASA Astrophysics Data System (ADS)

Efforts are beginning to include oceanic ecosystem models in global simulations of the carbon cycle, to improve the representations of primary production and of the resulting oceanic uptake of carbon dioxide. Coupling complicated ecosystem models with three dimensional physical models to obtain meaningful simulations poses several challenges. Before proceeding to a three dimensional implementation, we have undertaken this study using a one dimensional model to address challenges relevant to simulating the fate of dissolved and particulate organic matter. We embedded a formulation for the cycling of dissolved organic matter (DOM) via the microbial food web (MFW) into a nitrogen-based oceanic ecosystem model (the NEMURO model developed by the PICES program). The formulation of Anderson and Williams [1999] for the cycling of dissolved organic carbon (DOC) was converted to a nitrogen-based formulation including the same three fractions of DOM: labile (L-), semi-labile (S-) and refractory (R-), as dissolved organic nitrogen (DON). We used this ecosystem model, coupled to a one dimensional physical model, to simulate the Hawaii Ocean Time-series Station ALOHA for 1997 and 1998. We compared our simulations to data for nitrate, silicate, DON, DOC, PON and POC. Despite the deficiencies of the physical model, the ecosystem model reasonably simulated the vertical distribution of total DON, without tuning of parameters for the this site. However, it simulated too steep a decline in DON with depth below the photic zone. The simulated C:N ratio of DOM was also too low in the near surface waters. We found that the assumption of Redfield stoichiometry was inconsistent with the data for non-refractory DOM and for POM at Station ALOHA. Data from other locations also reveal C:N ratios higher than Redfield values. To use nitrogen-based models such as this to simulate the carbon cycle with confidence, we must improve their representations of the C:N ratio of DOM and POM.

Smith, S. L.; Yamanaka, Y.; Kishi, M. J.

2001-05-01

153

Results for the DWPF Slurry Mix Evaporator Condensate Tank, Off Gas Condensate Tank, And Recycle Collection Tank Samples  

SciTech Connect

The Defense Waste Processing Facility, DWPF, currently generates approximately 1.4 million gallons of recycle water per year during Sludge-Only operations. DWPF has minimized condensate generation to 1.4 million gallons by not operating the Steam Atomized Scrubbers, SASs, for the melter off gas system. By not operating the SASs, DWPF has reduced the total volume by approximately 800,000 gallons of condensate per year. Currently, the recycle stream is sent to back to the Tank Farm and processed through the 2H Evaporator system. To alleviate the load on the 2H Evaporator system, an acid evaporator design is being considered as an alternate processing and/or concentration method for the DWPF recycle stream. In order to support this alternate processing option, the DWPF has requested that the chemical and radionuclide compositions of the Off Gas Condensate Tank, OGCT, Slurry Mix Evaporator Condensate Tank, SMECT, Recycle Collection Tank, RCT, and the Decontamination Waste Treatment Tank, DWTT, be determined as a part of the process development work for the acid evaporator design. Samples have been retrieved from the OGCT, RCT, and SMECT and have been sent to the Savannah River National Laboratory, SRNL for this characterization. The DWTT samples have been recently shipped to SRNL. The results for the DWTT samples will be issued at later date.

TERRI, FELLINGER

2004-12-21

154

Suspended sediments in river ecosystems: Photochemical sources of dissolved organic carbon, dissolved organic nitrogen, and adsorptive removal of dissolved iron  

NASA Astrophysics Data System (ADS)

We generated suspended sediment solutions using river sediments and river water at concentrations similar to those observed during 1.5 year floods (Q1.5) and a dam removal (325 mg L-1) on the Deep River, North Carolina. Suspended sediment solutions were exposed to simulated solar radiation, equivalent to one clear, summer day at the study site (35N). Concentrations of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), total dissolved nitrogen (TDN), dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON), soluble reactive phosphorus (SRP) and total dissolved iron (Fed) were measured before and after exposure. Total dissolved carbon (TDC) budgets for each experiment were produced using DOC and DIC data. Sediment suspensions in the presence of simulated solar radiation were significant sources of dissolved C (119 11 ?mol C L-1 d-1; values indicate 1 standard error) and DON (1.7 0.5 ?mol N L-1 d-1) but not DIN or SRP. Extrapolations through the Deep River water column suggest that suspended sediments in the presence of light represent dissolved organic matter fluxes of 3.92 mmol C m-2 d-1 and 40 ?mol N m-2 d-1. Additionally, sediment suspensions lowered river water Fed concentrations immediately (24%) and progressively (40-90%) in both light and dark treatments. Our research suggests suspended sediments in river ecosystems are potential sources of dissolved organic C and dissolved organic N while effectively removing Fed from the water column.

Riggsbee, J. Adam; Orr, Cailin H.; Leech, Dina M.; Doyle, Martin W.; Wetzel, Robert G.

2008-09-01

155

Dissolved Oxygen Protocol  

NSDL National Science Digital Library

The purpose of this resource is to measure the amount of oxygen dissolved in water. Students use a dissolved oxygen kit or meter to measure the dissolved oxygen in the water at their hydrology site. The exact procedure depends on the instructions in the dissolved oxygen kit or meter used. The meter requires calibration before use.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

156

Chemistry Review: Dissolving  

NSDL National Science Digital Library

This resource clearly defines and summarizes all the aspects of the dissolving of liquids, with detailed examples of different substances dissolving together. There are videos that show dissolving examples, as well as models that show substances at their molecular level. The chemical make-up of substances such as water and oil are included to better understand the dissolving process and to learn which substances dissolve and which ones do not.

Kessler, James; Galvan, Patti

2010-01-01

157

Low-Level waste phase 1 melter testing off gas and mass balance evaluation  

SciTech Connect

Commercially available melter technologies were tested during 1994-95 as part of a multiphase program to test candidate technologies for vitrification of the low-level waste (LLW) stream to be derived from retrieval and pretreatment of Hanford Site tank wastes. Seven vendors were selected for Phase 1 testing to demonstrate vitrification of a high sodium content liquid LLW simulant. The tested melter technologies included four Joule-heated melters, a carbon electrode melter, a combustion melter, and a plasma melter. Various dry and slurry melter feed preparation processes were also tested. Various feed material samples, product glass samples, and process offgas streams were characterized to provide data for evaluation of process decontamination factors and material mass balances for each vitrification technology. This report describes the melter mass balance evaluations and results for six of the Phase 1 LLW melter vendor demonstration tests.

Wilson, C.N.

1996-06-28

158

Orientation and dynamics of benzyl alcohol and benzyl alkyl ethers dissolved in nematic lyotropic liquid crystals. 2H NMR and molecular dynamics simulations.  

PubMed

Most drugs have to cross cell membranes to reach their final target. A better understanding of the distribution, interactions, and dynamics of biologically active molecules in model bilayers is of fundamental importance in understanding drug functioning and design. 2H NMR quadrupole splittings (delta nu(Q)) and longitudinal relaxation times (T1) from the aromatic ring of benzyl alcohol-d5 (C0), a commonly used anesthetic, and a series of linear alkyl benzyl-d5 ethers with chain lengths from 1 to 12 carbon atoms (C1-C12), were measured. The molecules were dissolved in a nematic discotic lyotropic liquid crystal solution made of tetradecyltrimethylammonium chloride (TTAC)/decanol (DeOH)/NaCl/H2O. Values of delta nu(Q) and T1 from 1,1-dideuteriodecanol (15% enriched) and DHO (H2O with 0.2% D2O) were also measured. Delta nu(Q) of DeOH and DHO remained constant throughout the series. The value of delta nu(Q) of the para position of the ring (delta nu(p)) in C1 is 30% smaller than the delta nu(p) of C0. This is attributed to the existence of an H-bond between the alcohol hydroxyl proton and the solvent, which influences the average orientation of the ring. The relaxation data show that T1o,m is always longer than T1p and both decrease with the increase in alkyl chain length. Molecular dynamics simulations of the experimentally studied systems were performed. The aggregate was represented as a bilayer. The distribution, average orientation, and order parameters of the aromatic ring of the guest molecules in the bilayer were examined. Rotational correlation functions of all the C-D bonds and the OH bond from H2O were evaluated, allowing an estimate of the correlation times and T1. According to these results all spins relax in extreme narrowing conditions, except DeOH. Experimental and calculated T1 values differ at most by a factor of 3. However, the order of magnitude and the observed trends are well reproduced by the calculations. The aromatic ring of C0 possesses a unique average orientation in the bilayer. For the ether series, the orientation is modified and the C2 symmetry axis of the aromatic ring is exchanging between two orientations averaging the quadrupole splittings from the ortho and meta positions. The simulation supports the existence of an H-bond between C0 and the solvent not found in the ethers, which should be responsible for the observed differences. PMID:16834016

Ahumada, H; Montecinos, R; Tieleman, D P; Weiss-Lpez, B E

2005-08-01

159

FY'99 final report for the expedited technology demonstration project: demonstration test results for the MSO\\/off-gas and salt recycle system  

Microsoft Academic Search

Molten Salt Oxidation (MSO) is a promising alternative to incineration for the treatment of a variety of organic wastes. Lawrence Livermore National Laboratory (LLNL) has prepared a facility in which an integrated pilot-scale MSO treatment system is being tested and demonstrated. The system consists of a MSO vessel with a dedicated off-gas treatment system, a salt recycle system, feed preparation

M G Adamson; P C Hsu

1999-01-01

160

R and D for an off-gas treatment system for a slagging pyrolysis radioactive waste incinerator. Final report for Phase II  

Microsoft Academic Search

An analysis of the transport rates for volatilized species in off-gas from the slagging pyrolysis incinerator proposed for the incineration of buried and stored INEL radioactive wastes showed that the only major species that may interfere with operation of the incinerator will be lead oxide vapor and possibly hydrochloric acid. From the regulatory point of view, a decontamination factor (DF)

J. D. Christian; R. C. Girton; B. E. Kirstein; D. T. Pence

1978-01-01

161

Hot Corrosion of Inconel 625 Overlay Weld Cladding in Smelting Off-Gas Environment  

NASA Astrophysics Data System (ADS)

Degradation mechanisms and hot corrosion behavior of weld overlay alloy 625 were studied. Phase structure, morphology, thermal behavior, and chemical composition of deposited salt mixture on the weld overlay were characterized utilizing XRD, SEM/EDX, DTA, and ICP/OES, respectively. Dilution level of Fe in the weldment, dendritic structure, and degradation mechanisms of the weld were investigated. A molten phase formed on the weld layer at the operating temperature range of the boiler, which led to the hot corrosion attack in the water wall and the ultimate failure. Open circuit potential and weight-loss measurements and potentiodynamic polarization were carried out to study the hot corrosion behavior of the weld in the simulated molten salt medium at 873 K, 973 K, and 1073 K (600 C, 700 C, and 800 C). Internal oxidation and sulfidation plus pitting corrosion were identified as the main hot corrosion mechanisms in the weld and boiler tubes. The presence of a significant amount of Fe made the dendritic structure of the weld susceptible to preferential corrosion. Preferentially corroded (Mo, Nb)-depleted dendrite cores acted as potential sites for crack initiation from the surface layer. The penetration of the molten phase into the cracks accelerated the cracks' propagation mainly through the dendrite cores and further crack branching/widening.

Mohammadi Zahrani, E.; Alfantazi, A. M.

2013-10-01

162

TREATMENT TANK OFF-GAS TESTING FOR THE ENHANCED CHEMICAL CLEANING PROCESS  

SciTech Connect

The purpose of this activity was to provide a bounding estimate of the volume of hydrogen gas generated during Enhanced Chemical Cleaning (ECC) of residual sludge remaining in a Type I or Type II treatment tank as well as to provide results independent of the sludge volume in the waste tank to be cleaned. Previous testing to support Chemical Cleaning was based on a 20:1 oxalic acid to sludge ratio. Hydrogen gas evolution is the primary safety concern. Sealed vessel coupon tests were performed to estimate the hydrogen generation rate due to corrosion of carbon steel by 2.5 wt.% oxalic acid. These tests determined the maximum instantaneous hydrogen generation rate, the rate at which the generation rate decays, and the total hydrogen generated. These values were quantified based on a small scale methodology similar to the one described in WSRC-STI-2007-00209, Rev. 0. The measured rates support identified Safety Class functions. The tests were performed with ASTM A285 Grade C carbon steel coupons. Bounding conditions were determined for the solution environment. The oxalic acid concentration was 2.5 wt.% and the test temperature was 75 C. The test solution was agitated and contained no sludge simulant. Duplicate tests were performed and showed excellent reproducibility for the hydrogen generation rate and total hydrogen generated. The results showed that the hydrogen generation rate was initially high, but decayed rapidly within a couple of days. A statistical model was developed to predict the instantaneous hydrogen generation rate as a function of exposure time by combining both sets of data. An upper bound on the maximum hydrogen generation rate was determined from the upper 95% confidence limit. The upper bound confidence limit for the hydrogen generation rate is represented by the following equation. ln (G{sub v}) = -8.22-0.0584 t + 0.0002 t{sup 2}. This equation should be utilized to estimate the instantaneous hydrogen generation rate per unit surface area, G{sub v}, at a given time, t. The units for G{sub v} and t are ft{sup 3}/ft{sup 2}/min and hours, respectively. The total volume of hydrogen gas generated during the test was calculated from the model equation. An upper bound on the total gas generated was determined from the upper 95% confidence limit. The upper bound limit on the total hydrogen generated during the 163 hour test was 0.332 ft{sup 3}/ft{sup 2}. The maximum instantaneous hydrogen generation rate for this scenario is greater than that previously measured in the 8 wt.% oxalic acid tests due to both the absence of sludge in the test (i.e., greater than 20:1 ratio of acid to sludge) and the use of polished coupons (vs. mill scale coupons). However, due to passivation of the carbon steel surface, the corrosion rate decays by an order of magnitude within the first three days of exposure such that the instantaneous hydrogen generation rates are less than that previously measure in the 8 wt.% oxalic acid tests. While the results of these tests are bounding, the conditions used in this study may not be representative of the ECC flowsheet, and the applicability of these results to the flowsheet should be evaluated for the following reasons: (1) The absence of sludge results in higher instantaneous hydrogen generation rates than when the sludge is present; and (2) Polished coupons do not represent the condition of the carbon steel interior of the tank, which are covered with mill scale. Based on lower instantaneous corrosion rates measured on mill scale coupons exposed to oxalic acid, lower instantaneous hydrogen generation rates are expected for the tank interior than measured on the polished coupons. Corrosion rates were determined from the coupon tests and also calculated from the measured hydrogen generation rates. Excellent agreement was achieved between the time averaged corrosion rate calculated from the hydrogen generation rates and the corrosion rates determined from the coupon tests. The corrosion rates were on the order of 18 to 28 mpy. Good agreement was also observed between the maximum instantaneo

Wiersma, B.

2011-08-29

163

Modeling aerobic carbon oxidation and storage by integrating respirometric, titrimetric, and off-gas CO2 measurements.  

PubMed

A method for detailed investigation of aerobic carbon degradation processes by microorganisms is presented. The method relies on an integrated use of the respirometric, titrimetric, and off-gas CO(2) measurements. The oxygen uptake rate (OUR), hydrogen ion production rate (HPR), and the carbon dioxide transfer rate (CTR) resulting from the biological as well as physicochemical processes, coupled with a metabolic model characterizing both the growth and carbon storage processes, enables the comprehensive study of the carbon degradation processes. The method allows the formation of carbon storage products and the biomass growth rates to be estimated without requiring any off-line biomass or liquid-phase measurements, although the practical identifiability of the system could be improved with additional measurements. Furthermore, the combined yield for biomass growth and carbon storage is identifiable, along with the affinity constant with respect to the carbon substrate. However, the individual yields for growth and carbon storage are not identifiable without further knowledge about the metabolic pathways employed by the microorganisms in the carbon conversion. This is true even when more process variables are measured. The method is applied to the aerobic carbon substrate degradation by a full-scale sludge using acetate as an example carbon source. The sludge was able to quickly take up the substrate and store it as poly-beta-hydroxybutyrate (PHB). The PHB formation rate was a few times faster than the biomass growth rate, which was confirmed by off-line liquid- and solid-phase analysis. The estimated combined yield for biomass growth and carbon storage compared closely to that determined from the theoretical yields reported in literature based on thermodynamics. This suggests that the theoretical yields may be used as default parameters for modeling purposes. PMID:15449301

Pratt, Steven; Yuan, Zhiguo; Keller, Jurg

2004-10-20

164

Optimal operation of the boil-off gas compression process using a boil-off rate model for LNG storage tanks  

Microsoft Academic Search

Proper handling of boil-off gas (BOG) significantly affects the operational efficiency as well as the safety of the whole\\u000a LNG gasification plant. Due to the not well-known inherent dynamics, it has been suspected that the BOG compressors are being\\u000a operated at too much capacity, unnecessarily consuming too much energy. An empirical model is proposed for the estimation\\u000a of the boil-off

Myung Wook Shin; Dongil Shin; Soo Hyoung Choi; En Sup Yoon

2008-01-01

165

Flooding and mass transfer in Goodloe-packed columns. [For Kr absorption in liquid CO in HTGR off-gas systems  

Microsoft Academic Search

Flooding and mass transfer experiments were performed with a CO-air\\/water system to examine mass transfer characteristics in Goodloe-packed columns of 6.4 and 15.2-cm ID for removal of radioactive Kr from HTGR off-gas. The flooding experiments verified previous correlations for the packing. The plug flow model was selected for calculation of the overall mass transfer coefficient, K\\/sub L\\/a. The correlation for

E. I. Chao; R. J. Bertolami; J. L. P. Varlet; G. R. Wilkes

1976-01-01

166

AFCI Coupled End-to-End Research,Development and Demonstration Project: Integrated Off-gas Treatment System Design and Initial Performance - 9226  

SciTech Connect

Oak Ridge National Laboratory is conducting a complete, coupled end-to-end (CETE) demonstration of advanced nuclear fuel reprocessing to support the Advanced Fuel Cycle Initiative. This small-scale reprocessing operation provides a unique opportunity to test integrated off-gas treatment systems designed to recover the primary volatile fission and activation products (H-3, C-14, Kr-85, and I-139) released from the spent nuclear fuel (SNF). The CETE project will demonstrate an advanced head-end process, referred to as voloxidation, designed to condition the SNF, separate the SNF from the cladding, and release tritium contained in the fuel matrix. The off-gas from the dry voloxidation process as well as from the more traditional fuel dissolution process will be treated separately and the volatile components recovered. This paper provides descriptions of the off-gas treatment systems for both the voloxidation process and for the fuel dissolution process and provides preliminary results from the initial CETE processing runs. Impacts of processing parameters on the relative quantities of volatile components released and recovery efficiencies are evaluated.

Jubin, Robert Thomas [ORNL; Patton, Bradley D [ORNL; Ramey, Dan W [ORNL; Spencer, Barry B [ORNL

2009-01-01

167

Dissolver vessel bottom assembly  

DOEpatents

An improved bottom assembly is provided for a nuclear reactor fuel reprocessing dissolver vessel wherein fuel elements are dissolved as the initial step in recovering fissile material from spent fuel rods. A shock-absorbing crash plate with a convex upper surface is disposed at the bottom of the dissolver vessel so as to provide an annular space between the crash plate and the dissolver vessel wall. A sparging ring is disposed within the annular space to enable a fluid discharged from the sparging ring to agitate the solids which deposit on the bottom of the dissolver vessel and accumulate in the annular space. An inlet tangential to the annular space permits a fluid pumped into the annular space through the inlet to flush these solids from the dissolver vessel through tangential outlets oppositely facing the inlet. The sparging ring is protected against damage from the impact of fuel elements being charged to the dissolver vessel by making the crash plate of such a diameter that the width of the annular space between the crash plate and the vessel wall is less than the diameter of the fuel elements.

Kilian, Douglas C. (Kennewick, WA)

1976-01-01

168

Electrochemistry of Dissolved Gases.  

National Technical Information Service (NTIS)

The electrochemistry of various dissolved gases has been investigated as a function of the gas, solution pH, supporting electrolyte, electrode material, and the preconditioning of the electrode surfaces. These investigations have been conducted through th...

D. T. Sawyer

1965-01-01

169

Sequence and transcriptional analysis of the genes responsible for curdlan biosynthesis in Agrobacterium sp. ATCC 31749 under simulated dissolved oxygen gradients conditions.  

PubMed

Expression at the mRNA level of ten selected genes in Agrobacterium sp. ATCC 31749 under various dissolved oxygen (DO) levels during curdlan fermentation related to electron transfer chain (ETC), tricarboxylic acid (TCA) cycle, peptidoglycan/lipopolysaccharide biosynthesis, and uridine diphosphate (UDP)-glucose biosynthesis were determined by qRT-PCR. Experiments were performed at DO levels of 30%, 50%, and 75%, as well as under low-oxygen conditions. The effect of high cell density on transcriptional response of the above genes under low oxygen was also studied. Besides cytochrome d (cyd A), the transcription levels of all the other genes were increased at higher DO and reached maximum at 50% DO. Under 75% DO, the transcriptional levels of all the genes were repressed. In addition, transcription levels of icd, sdh, cyo A, and fix N genes did not exhibit significant fluctuation with high cell density culture under low oxygen. These results suggested a mechanism for DO regulation of curdlan synthesis through regulation of transcriptional levels of ETCs, TCA, and UDP-glucose synthesis genes during curdlan fermentation. To our knowledge, this is the first report that DO concentration apparently regulates curdlan biosynthesis in Agrobacterium sp. ATCC 31749 providing essential lead for the optimization of the fermentation at the industrial scale. PMID:21472535

Zhang, Hong-Tao; Zhan, Xiao-Bei; Zheng, Zhi-Yong; Wu, Jian-Rong; Yu, Xiao-Bin; Jiang, Yun; Lin, Chi-Chung

2011-04-07

170

Simulation of dissolved oxygen and biochemical oxygen demand, Plantation Canal, Broward County, Florida with an evaluation of the QUAL-I model for use in south Florida  

USGS Publications Warehouse

A mathematical model; QUAL-I, developed by the Texas Water Development Board, was evaluated as a management tool in predicting the spatial and temporal distribution of dissolved oxygen and biochemical oxygen demand in Plantation Canal. Predictions based on the QUAL-I model, which was verified only against midday summer-flow conditions, showed that improvement of quality of inflows from sewage treatment plants and use of at least 130 cubic feet per second of dilution water would improve water quality in the canal significantly. The model was not fully amenable to use on Plantation Canal because: (1) it did not consider photosynthetic production, nitrification, and benthic oxygen demand as sources and sinks of oxygen; (2) the model assumptions of complete mixing, transport, and steady state were not met; and (3) the data base was inadequate because it consisted of only one set of data for each case. However, it was felt that meaningful results could be obtained for some sets of conditions. (Woodard-USGS)

Russo, Thomas N.; McQuivey, Raul S.

1975-01-01

171

Dissolved Oxygen in Water  

Microsoft Academic Search

\\u000a After performing this experiment, the student shall be able to:\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a \\u000a \\u000a Determine the level of dissolved oxygen in a sample of water using Winklers method.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a \\u000a Analyze the effects of various factors on the level of dissolved oxygen in a water sample (e.g., salt content, temperature,\\u000a degree of mixing, and the presence of reducing compounds).

Jorge G. Ibanez; Margarita Hernandez-Esparza; Carmen Doria-Serrano; Arturo Fregoso-Infante; Mono Mohan Singh

172

Melting and dissolving  

NASA Astrophysics Data System (ADS)

The different modes of convection which may arise in diffusion-governed melting of a pure solid into a binary melt, when the interface between the solid and the melt is horizontal are investigated. It is shown that, in the dissolving regime, a relatively warm solid may dissolve into a relatively cold liquid. The nature of the convection which may arise as the geometry and the melt composition are varied is determined by calculating the difference between the density of the melt at the solid interface and the density of the liquid far from the interface. The analysis is generalized by considering binary solid solutions.

Woods, Andrew W.

1992-06-01

173

Dissolved Oxygen Activity  

NSDL National Science Digital Library

One of the most important measures of the health of the stream is the level of dissolved oxygen (DO) in the water. Oxygen (O2) dissolves in water through the mixing of the water surface with the atmosphere. The oxygen is used by fish and other animals in the water to "breath" through their gills or other respiratory systems and by plants. If the levels fall too low, many species of fish, macroinvertebrates, and plants cannot survive. At very low levels of oxygen, the stream becomes "septic" and smells rotten because low oxygen sulfur bacteria begin to dominate.

Gordon, Steve

174

Dissolved Oxygen Model  

NSDL National Science Digital Library

One of the most important measures of the health of the stream is the level of dissolved oxygen (DO) in the water. Oxygen (O2) dissolves in water through the mixing of the water surface with the atmosphere. The oxygen is used by fish and other animals in the water to "breath" through their gills or other respiratory systems and by plants. If the levels fall too low, many species of fish, macroinvertebrates, and plants cannot survive. At very low levels of oxygen, the stream becomes "septic" and smells rotten because low oxygen sulfur bacteria begin to dominate.

Gordon, Steve

175

Temperature Affects Dissolving  

NSDL National Science Digital Library

In this activity will compare how well cocoa mix dissolves in cold and hot water. They will see that cocoa mix dissolves much better in hot water. There is a downloadable activity sheet that will be very helpful to educators, and will help students stay on track. An assessment sheet is also available on the activity page to keep track of students progress. There is also a step by step guide as to how to perform the experiment, and how to introduce it t the students.

Kessler, James; Galvan, Patti

2010-01-01

176

Lap-Dissolve Slides  

ERIC Educational Resources Information Center

|Discusses the use of lap-dissolve projection to give students pre-laboratory instruction on an upcoming experiment. In this technique, two slide projectors are operated alternately so that one visual image fades away while the next appears on the same screen area. (MLH)|

Fine, Leonard W.; And Others

1977-01-01

177

Dissolving a Partnership Efficiently  

Microsoft Academic Search

Several partners jointly own an asset that may be traded among them. Each partner has a valuation for the asset. The valuations are known privately and drawn independently from a common probability distribution. The authors characterize the set of all incentive- compatible and interim individually-rational trading mechanisms, and give a simple necessary and sufficient condition for such mechanisms to dissolve

Peter Cramton; Robert Gibbons; PAUL KLEMPERERI

1987-01-01

178

A Dissolving Challenge  

NSDL National Science Digital Library

In this activity, learners add objects and substances to carbonated water to discover that added objects increase the rate at which dissolved gas comes out of solution. Learners are then challenged to make a lemon soda that retains as much carbonation as possible, by using carbonated water, sugar, and lemon juice. Learners identify the difficulty in making a fizzy lemon soda, develop a better method, and then test it.

Kessler, James H.; Galvan, Patricia M.

2007-01-01

179

CASAA Dissolvables - Attachment 6 1  

Center for Biologics Evaluation and Research (CBER)

Text Version... CASAA Dissolvables - Attachment 6 1 Content withheld for copyright purposes Page 2. CASAA Dissolvables - Attachment 6 2 ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

180

ADDING REALISM TO NUCLEAR MATERIAL DISSOLVING ANALYSIS  

SciTech Connect

Two new criticality modeling approaches have greatly increased the efficiency of dissolver operations in H-Canyon. The first new approach takes credit for the linear, physical distribution of the mass throughout the entire length of the fuel assembly. This distribution of mass is referred to as the linear density. Crediting the linear density of the fuel bundles results in using lower fissile concentrations, which allows higher masses to be charged to the dissolver. Also, this approach takes credit for the fact that only part of the fissile mass is wetted at a time. There are multiple assemblies stacked on top of each other in a bundle. On average, only 50-75% of the mass (the bottom two or three assemblies) is wetted at a time. This means that only 50-75% (depending on operating level) of the mass is moderated and is contributing to the reactivity of the system. The second new approach takes credit for the progression of the dissolving process. Previously, dissolving analysis looked at a snapshot in time where the same fissile material existed both in the wells and in the bulk solution at the same time. The second new approach models multiple consecutive phases that simulate the fissile material moving from a high concentration in the wells to a low concentration in the bulk solution. This approach is more realistic and allows higher fissile masses to be charged to the dissolver.

Williamson, B.

2011-08-15

181

FINAL REPORT DM1200 TESTS WITH AZ 101 HLW SIMULANTS VSL-03R3800-4 REV 0 2/17/04  

SciTech Connect

This report documents melter and off-gas performance results obtained on the DM 1200 HLW Pilot Melter during processing of simulated HLW AZ-101 feed. The principal objectives of the DM1200 melter testing were to determine the achievable glass production rates for simulated HLW AZ-101 feed; determine the effect of bubbling rate and feed solids content on production rate; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and to perform pre- and post-test inspections of system components. The test objectives (including test success criteria), along with how they were met, are outlined in a table.

KRUGER AA; MATLACK KS; BARDAKCI T; D'ANGELO NA; GONG W; KOT WK; PEGG IL

2011-12-29

182

Suspended sediments in river ecosystems: Photochemical sources of dissolved organic carbon, dissolved organic nitrogen, and adsorptive removal of dissolved iron  

Microsoft Academic Search

We generated suspended sediment solutions using river sediments and river water at concentrations similar to those observed during 1.5 year floods (Q1.5) and a dam removal (?325 mg L?1) on the Deep River, North Carolina. Suspended sediment solutions were exposed to simulated solar radiation, equivalent to one clear, summer day at the study site (35N). Concentrations of dissolved organic carbon

J. Adam Riggsbee; Cailin H. Orr; Dina M. Leech; Martin W. Doyle; Robert G. Wetzel

2008-01-01

183

Method for dissolving plutonium dioxide  

DOEpatents

The fluoride-catalyzed, non-oxidative dissolution of plutonium dioxide in HNO.sub.3 is significantly enhanced in rate by oxidizing dissolved plutonium ions. It is believed that the oxidation of dissolved plutonium releases fluoride ions from a soluble plutonium-fluoride complex for further catalytic action.

Tallent, Othar K. (Oak Ridge, TN)

1978-01-01

184

How to Measure Dissolved Oxygen  

NSDL National Science Digital Library

This web page, hosted by the Washington State Department of Ecology, offers a general overview of dissolved oxygen and how it is measured. It includes protocols for measuring dissolved oxygen in turbulent waters as well as using the Winkler titration method. The site also features links to measuring other water quality parameters such as pH, nutrients, and turbidity.

Ecology, Washington S.

185

Vitrification of Simulated LILW Using Induction Cold Crucible Melter Technology  

Microsoft Academic Search

Vitrification destroys hazardous organics, and immobilizes heavy metals and radioactive elements to form a chemically durable and highly leach-resistant vitrified form. The vitrification process provides exceptional volume reduction and is attractive for minimizing disposal volume. A pilot plant test using an induction Cold Crucible Melter (CCM) fitted with an off-gas treatment system (OGTS) has been conducted to vitrify a simulated

C. W. Kim; J. K. Park; S. W. Shin; T. W. Hwang; J. H. Ha; M. J. Song

2006-01-01

186

METHOD OF DISSOLVING MASSIVE PLUTONIUM  

DOEpatents

Massive plutonium can be dissolved in a hot mixture of concentrated nitric acid and a small quantity of hydrofluoric acid. A preliminary oxidation with water under superatmospheric pressure at 140 to 150 deg C is advantageous

Facer, J.F.; Lyon, W.L.

1960-06-28

187

Reducing emissions from uranium dissolving  

SciTech Connect

This study was designed to assess the feasibility of decreasing NO[sub x] emissions from the current uranium alloy scrap tray dissolving facility. In the current process, uranium scrap is dissolved in boiling nitric acid in shallow stainless-steel trays. As scrap dissolves, more metal and more nitric acid are added to the tray by operating personnel. Safe geometry is assured by keeping liquid level at or below 5 cm, the depth of a safe infinite slab. The accountability batch control system provides additional protection against criticality. Both uranium and uranium alloys are dissolved. Nitric acid is recovered from the vapors for reuse. Metal nitrates are sent to uranium recovery. Brown NO[sub x] fumes evolved during dissolving have occasionally resulted in a visible plume from the trays. The fuming is most noticeable during startup and after addition of fresh acid to a tray. Present environmental regulations are expected to require control of brown NO[sub x] emissions. A detailed review of the literature, indicated the feasibility of slightly altering process chemistry to favor the production of NO[sub 2] which can be scrubbed and recycled as nitric acid. Methods for controlling the process to manage offgas product distribution and to minimize chemical reaction hazards were also considered.

Griffith, W.L.; Compere, A.L.; Huxtable, W.P.; Googin, J.M.

1992-10-01

188

Reducing emissions from uranium dissolving  

SciTech Connect

This study was designed to assess the feasibility of decreasing NO{sub x} emissions from the current uranium alloy scrap tray dissolving facility. In the current process, uranium scrap is dissolved in boiling nitric acid in shallow stainless-steel trays. As scrap dissolves, more metal and more nitric acid are added to the tray by operating personnel. Safe geometry is assured by keeping liquid level at or below 5 cm, the depth of a safe infinite slab. The accountability batch control system provides additional protection against criticality. Both uranium and uranium alloys are dissolved. Nitric acid is recovered from the vapors for reuse. Metal nitrates are sent to uranium recovery. Brown NO{sub x} fumes evolved during dissolving have occasionally resulted in a visible plume from the trays. The fuming is most noticeable during startup and after addition of fresh acid to a tray. Present environmental regulations are expected to require control of brown NO{sub x} emissions. A detailed review of the literature, indicated the feasibility of slightly altering process chemistry to favor the production of NO{sub 2} which can be scrubbed and recycled as nitric acid. Methods for controlling the process to manage offgas product distribution and to minimize chemical reaction hazards were also considered.

Griffith, W.L.; Compere, A.L.; Huxtable, W.P.; Googin, J.M.

1992-10-01

189

The interaction of iodine with insoluble residue in the dissolution of simulated spent-fuel pellets  

SciTech Connect

To properly control radioiodine ({sup 129}I) when reprocessing nuclear fuels, it is important to understand the interaction between iodine and the insoluble residue produced during the dissolution of spent fuels. Simulated spent-fuel pellets ({approximately} 1 g each) equivalent to spent fuel with a burnup of 5% fima were dissolved in 4.1 M HNO{sub 3} or a simulated spent-fuel solution to examine this interaction and the material balance of iodine. In dissolution in 4.1 M HNO{sub 3}, 2 to 5% of the iodine in the pellet is conveyed to the insoluble residue (8 {plus minus} 1 mg), 1 to 5% remains in solution, and the balance volatilizes into the off-gas. The process that incorporates iodine into the residue is the formation of slightly soluble iodides, such as PdI{sub 2} and AgI, on the surface of the residue. The quantity of iodine in the residue averages 1.1 {plus minus} 0.5 Mg I/mg of residue. Pellet dissolution in simulated spent-fuel solutions with a uranium concentration of {ge}170 g U/{ell} and corresponding amounts of fission product elements causes a marked increase in the amount of residue and a significant increase in the amount of iodine involved. This phenomenon is due to the secondary precipitation of some metal molybdates. The PdI{sub 2} and AgI in the residue are in equilibrium with Pd{sup 2+}, Ag{sup +}, and I{sup {minus}} in the solution. The I{sup {minus}} can be oxidized into I{sub 2} in a hot nitric acid solution bubbled with NO{sub 2}. The action of NO{sub 2} causes part of the iodine in the residue to be eluted into the solution and then volatilized into the off-gas during the operation to expel iodine (IO{sup {minus}}{sup 3}) form the solution. A process consisting of (a) heating of the residue in a IO{sup {minus}}{sub 3}-concentrated HNO{sub 3} at 100{degrees} C will transfer 50 to 90% of the iodine in the residue to the gas phase. The remaining iodine is probably inside the residue as it is difficult to remove.

Sakurai, T.; Takahashi, A.; Ishikawa, N.; Komaki, Y. (Japan Atomic Energy Research Inst., Physical Chemistry Lab., Tokai-mura, Ibaraki-ken 319-11 (JP))

1991-04-01

190

Dissolving a Substance in Different Liquids  

NSDL National Science Digital Library

In this activity, learners make colored sugar and add it to water, alcohol, and oil to discover some interesting differences in dissolving. The sugar will dissolve to a different extent in each liquid, and the color may or may not dissolve depending on the liquid. Learners also have an opportunity to refine their definition of the term dissolve. Adult supervision recommended.

Kessler, James H.; Galvan, Patricia M.

2007-01-01

191

Dissolving Different Liquids in Water  

NSDL National Science Digital Library

In this activity, students add different liquids to water and apply their working definition of dissolving to their observations. After observing isopropyl rubbing alcohol, vegetable oil, and corn syrup in water, students can conclude that while some liquids may dissolve in water, different liquids dissolve in water to different extents. There is a downloadable activity sheet that will be very helpful to educators, and will help students stay on track. An assessment sheet is also available on the activity page to keep track of students progress. There is also a step by step guide as to how to perform the experiment, and how to introduce it t the students.

Kessler, James; Galvan, Patti

2010-01-01

192

PREDICTING DISSOLVED PHOSPHORUS IN RUNOFF FROM MANURED FIELD-PLOTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Dissolved P transport in surface runoff from agricultural soils to surface waters is an environmental concern. Computer models are used to assess the risk of P transport, but widely-used models do not simulate P in runoff from surface-applied manures. We therefore tested the quantitative runoff P mo...

193

Release of biodegradable dissolved organic matter from ancient sedimentary rocks  

Microsoft Academic Search

Sedimentary rocks contain the largest mass of organic carbon on Earth, yet these reservoirs are not well integrated into modern carbon budgets. Here we describe the release of dissolved organic matter (DOM) from OM-rich sedimentary rocks under simulated weathering conditions. Results from column experiments demonstrate slow, sustained release of DOM from ancient sedimentary rocks under simulated weathering conditions. 1H-NMR analysis

Sarah Schillawski; Steven Petsch

2008-01-01

194

Dissolved oxygen and fish behavior  

Microsoft Academic Search

Synopsis This essay reviews the behavioral responses of fish to reduced levels of dissolved oxygen from the perspective of optimization theory as used in contemporary behavioral ecology. A consideration of oxygen as a resource suggests that net oxygen gain per unit of energy expenditure will be the most useful currency for ecological models of breathing. In the process of oxygen

Donald L. Kramer

1987-01-01

195

Dissolving Pulp Industry. Market Trends.  

National Technical Information Service (NTIS)

The report presents a worldwide overview of the dissolving pulp industry and highlights of the industry in Alaska. It describes trends in world markets and major end-use markets, with special emphasis on the manufacture and use of textile, fibers in the U...

I. Durbak

1993-01-01

196

Phase fluorometric dissolved oxygen sensor  

Microsoft Academic Search

The design and performance of a ruggedised dissolved oxygen (DO) probe, which is based on phase fluorometric detection of the quenched fluorescence of an oxygen-sensitive ruthenium complex, is reported. The complex is entrapped in a porous hydrophobic solgel matrix that has been optimised for this application. The LED excitation and photodiode detection are employed in a dipstick probe configuration, with

C. McDonagh; C. Kolle; A. K. McEvoy; D. L. Dowling; A. A. Cafolla; S. J. Cullen; B. D. MacCraith

2001-01-01

197

Technical Notes: An Incubation System Allowing Multiple Dissolved Oxygen and Temperature Combinations for Salmonid Emergence Studies  

Microsoft Academic Search

The system described here provides a means to concurrently study the effects of multiple combinations of temperature and dissolved oxygen on salmonid emergence. The incubation chambers were filled with a gravel substrate to simulate natural conditions within a salmonid redd. The system operated for more than 2 months at three concurrent temperatures and four dissolved oxygen levels at each temperature.

William J. Miller

1992-01-01

198

Toxic and carcinogenic constituents in dissolvable tobacco ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Page 8. Tobacco-specific N-nitrosamines in Camel dissolvable products ... Page 9. Tobacco-specific N-nitrosamines in Camel dissolvable products ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

199

Dissolved Oxygen and Biochemical Oxygen Demand  

NSDL National Science Digital Library

This Environmental Protection Agency (EPA) website provides general information about dissolved oxygen, including what it is, sampling and equipment considerations, and sampling and analysis protocols. The site also features a chart of dissolved oxygen solubility as a function of temperature.

2010-03-02

200

Dissolved Oxygen and Biochemical Oxygen Demand  

NSDL National Science Digital Library

This EPA website provides general information about dissolved oxygen, including what it is, sampling and equipment considerations, and sampling and analysis protocols. The site also features a chart of dissolved oxygen solubility as a function of temperature.

Agency, U. S.

201

Delta-plutonium dissolving: A HAN process.  

National Technical Information Service (NTIS)

This report describes preliminary studies in the development of a nitrate-based method for dissolving delta-phase plutonium. The dissolving solution, a mixture of nitric acid, hydroxylammonium nitrate (HAN) and fluoride offers substantial advantages over ...

D. G. Karraker

1990-01-01

202

Water quality modeling of the effects of macrophytes on dissolved oxygen in a shallow tailwater reservoir  

Microsoft Academic Search

Lake Ogallala, a 260-hectare tailwater reservoir, is subject to wide fluctuations of inflow water quality and quantity. These fluctuations impact lake temperatures, water stage, dissolved oxygen (DO), and nutrients. A two-dimensional, continuous simulation hydrodynamic and water quality model, CE-QUAL-W2, was used to simulate dissolved oxygen levels and to quantify DO sources and sinks in the lake. The elements modeled include

J. Stansbury; L. Kozimor; D. Admiraal; E. Dove

2008-01-01

203

Simulations of Dissolved and Particulate Organic Matter with a Nitrogen-based Oceanic Ecosystem Model: A one Dimensional Model Applied to the Hawaii Ocean Time-series Station ALOHA  

Microsoft Academic Search

Efforts are beginning to include oceanic ecosystem models in global simulations of the carbon cycle, to improve the representations of primary production and of the resulting oceanic uptake of carbon dioxide. Coupling complicated ecosystem models with three dimensional physical models to obtain meaningful simulations poses several challenges. Before proceeding to a three dimensional implementation, we have undertaken this study using

S. L. Smith; Y. Yamanaka; M. J. Kishi

2001-01-01

204

R And D for an off-Gas Treatment System for a Slagging Pyrolysis Radioactive Waste Incinerator. Final Report for Phase III.  

National Technical Information Service (NTIS)

Results of engineering-scale tests to obtain sintered metal filter particulate removal performance data with fly ash to simulate the expected incinerator particulate are reported. Efficiencies of greater than 99.9999% were obtained at the conditions of th...

B. E. Kirstein W. J. Paplawsky D. T. Pence B. D. Snow M. E. Spaeth

1979-01-01

205

Tried and True: Inquiry-based dissolving  

NSDL National Science Digital Library

This project highlights a dissolving unit that was part of an eighth-grade, semester-long investigation into matter. During the dissolving unit, students explored the concepts of mixture, solution, dissolving, saturation, and conservation of mass. Dissolving is an advanced concept that involves the atomic structure of matter and the nature of chemical bonds. However, dissolving is also a common experience in students lives (e.g., when they mix sugar in lemonade). The unit allowed students to explore everyday materials in new ways, address common misconceptions, and pursue scientific discovery.

Benedis-Grab, Gregory; Petzoldt, Molly; Uribe, Lisbeth

2009-10-01

206

Recalcitrant dissolved organic carbon fractions.  

PubMed

Marine dissolved organic carbon (DOC) exhibits a spectrum of reactivity, from very fast turnover of the most bioavailable forms in the surface ocean to long-lived materials circulating within the ocean abyss. These disparate reactivities group DOC by fractions with distinctive functions in the cycling of carbon, ranging from support of the microbial loop to involvement in the biological pump to a hypothesized major source/sink of atmospheric CO(2) driving paleoclimate variability. Here, the major fractions constituting the global ocean's recalcitrant DOC pool are quantitatively and qualitatively characterized with reference to their roles in carbon biogeochemistry. A nomenclature for the fractions is proposed based on those roles. PMID:22881353

Hansell, Dennis A

2012-07-16

207

PROCESS OF DISSOLVING ZIRCONIUM ALLOYS  

DOEpatents

A process is described for dissolving binary zirconium-uranium alloys where the uranium content is about 2%. In prior dissolution procedures for these alloys, an oxidizing agent was added to prevent the precipitation of uranium tetrafluoride. In the present method complete dissolution is accomplished without the use of the oxidizing agent by using only the stoichiometric amount or slight excess of HF required by the zirconium. The concentration of the acid may range from 2M to 10M and the dissolution is advatageously carried out at a temperature of 80 deg C.

Shor, R.S.; Vogler, S.

1958-01-21

208

Simulators  

SciTech Connect

This book discusses the following topics: oil industry, gas industry, chemical process control, electricity supply generation, food industry, simulator applications, operator maintenance training, online process control, determination of safety limits and margins, the design implementation of the simulators, hardware aspects, space and power requirements, sensors, miniaturisation, low-cost mass storage, computer-generated imaging, optimisation of trainer design.

Not Available

1983-01-01

209

METHOD OF DISSOLVING REFRACTORY ALLOYS  

DOEpatents

This patent relates to the dissolution of alloys of uranium with zirconium, thorium, molybdenum, or niobium. The alloy is contacted with an anhydrous solution of mercuric chloride in a low-molecular-weight monohydric alcohol to produce a mercury-containing alcohol slurry. The slurry is then converted to an aqueous system by adding water and driving off the alcohol. The resulting aqueous slurry is electrolyzed in the presence of a mercury cathode to remove the mercury and produce a uranium-bearing aqueous solution. This process is useful for dissolving irradiated nuclear reactor fuels for radiochemical reprocessing by solvent extraction. In addition, zirconium-alloy cladding is selectively removed from uranium dioxide fuel compacts by this means. (AEC)

Helton, D.M.; Savolainen, J.K.

1963-04-23

210

Progress in dissolving modified LEU Cintichem targets  

SciTech Connect

A process is under development to use low-enriched uranium (LEU) metal targets for production of {sup 99}Mo. The first step is to dissolve the irradiated foil. In past work, this has been done by heating a closed (sealed) vessel containing the foil and a solution of nitric and sulfuric acids. In this work, the authors have demonstrated that (1) the dissolver solution can contain nitric acid alone, (2) uranium dioxide is also dissolved by nitric acid alone, and (3) barrier metals of Cu, Fe, or Ni on the U foil are also dissolved by nitric acid. Changes to the dissolver design and operation needed to accommodate the uranium foil are discussed, including (1) simple operations that are easy to do in a remote-maintenance facility, (2) heat removal from the irradiated LEU foil, and (3) cold trap operation with high dissolver pressures.

Leonard, R.A.; Chen, L.; Mertz, C.J.; Vandegrift, G.F. [Argonne National Lab., IL (United States). Chemical Technology Div.

1996-12-31

211

Simulations  

Microsoft Academic Search

\\u000a In this chapter, we use R to generate, examine, detect, and illuminate simulated yield tables, projections, or sets of possible\\u000a future forest conditions. Our objectives are to 1) cover the major topics and tasks required to generate forest forecasts;\\u000a 2) compare some common metrics from the resulting simulations; and 3) examine and present potential shortcomings and remedies\\u000a for the methods

Andrew P. Robinson; Jeff D. Hamann

212

Thermodynamic simulations of lignite-fired IGCC with in situ desulfurization and CO 2 capture  

Microsoft Academic Search

IGCC cycles running on Greek lignite with in situ desulfurization and CO2 capture were simulated using the ASPEN PLUS process simulator and compared with other power cycles. Dolomite was chosen as the material for in situ desulfurization. Considering the power produced and residual sulfur content of the off-gas, an oxygen-blown gasifier operated at 1.8 MPa and 950C, having a thermal

Wim F. Elseviers; Tania Van Mierlo; Martine J. F. Van de Voorde; Harry Verelst

1996-01-01

213

Selected conversion of NO/sub x/ by catalytic reduction with ammonia  

SciTech Connect

An effective off-gas treatment system is an environmental must in the reprocessing of nuclear fuels. An up-to-date progress report on such a treatment system is presented. During 1978, General Atomic Company (GA) completed the detailed design of a cold (radioactively) engineering-scale off-gas treatment system for spent nuclear fuel reprocessing. The GA off-gas treatment system is designed to process simulated radioactive or other noxious volatile and gaseous constituents in dissolver off-gas (DOG) streams indigenous to several nuclear fuel cycles, e.g., light-water reactors (LWRs), high-temperature gas-cooled reactors (HTGRs), and liquid-metal fast-breeder reactors (LMFBRs). The GA off-gas treatment system also has the capability to treat fluidized-bed burner off-gas (BOG) streams, which are specific for HTGR fuel reprocessing only.

Hirsch, P.M.

1982-02-01

214

The Role of Dissolved Organic Carbon, Dissolved Organic Nitrogen, and Dissolved Inorganic Nitrogen in a Tropical Wet Forest Ecosystem  

Microsoft Academic Search

Although tropical wet forests play an important role in the global carbon (C) and nitrogen (N) cycles, little is known about the origin, composition, and fate of dissolved organic C (DOC) and N (DON) in these ecosystems. We quantified and characterized fluxes of DOC, DON, and dissolved inorganic N (DIN) in throughfall, litter leachate, and soil solution of an old-growth

Luitgard Schwendenmann; Edzo Veldkamp

2005-01-01

215

Photochemical and microbial consumption of dissolved organic carbon and dissolved oxygen in the Amazon River system  

Microsoft Academic Search

Bacterial and photochemical mineralization of dissolved organic matter were investigated in the Amazon River system. Dissolved oxygen, dissolved organic carbon (DOC), and bacterial growth were measured during incubations conducted under natural sunlight and in the dark. Substrate addition experiments indicated that the relatively low rates of bacterial activity in Amazon River water were caused by C limitation. Experiments to determine

R. M. W. Amon; R. Benner

1996-01-01

216

A review of dissolved gas supersaturation literature  

Microsoft Academic Search

Gas bubble disease in a condition that affects aquatic animals residing in fresh or marine waters that are supersaturated with atmospheric gases. The majority of research concerning dissolved gas supersaturation has been stimulated by a serious supersaturation problem that was first observed in the Columbia and Snake river systems in 1970. Available literature dealing with dissolved gas supersaturation and recorded

DON E. WEITKAMP; MAX KATZ

1980-01-01

217

Investigating Students' Understanding of the Dissolving Process  

ERIC Educational Resources Information Center

In a previous study, the authors identified several student misconceptions regarding the process of dissolving ionic compounds in water. The present study used multiple-choice questions whose distractors were derived from these misconceptions to assess students' understanding of the dissolving process at the symbolic and particulate levels. The

Naah, Basil M.; Sanger, Michael J.

2013-01-01

218

Investigating Students' Understanding of the Dissolving Process  

ERIC Educational Resources Information Center

|In a previous study, the authors identified several student misconceptions regarding the process of dissolving ionic compounds in water. The present study used multiple-choice questions whose distractors were derived from these misconceptions to assess students' understanding of the dissolving process at the symbolic and particulate levels. The

Naah, Basil M.; Sanger, Michael J.

2013-01-01

219

Fish Passage Through a Simulated Horizontal Bulb Turbine Pressure Regime: A Supplement to"Laboratory Studies of the Effects of Pressure and Dissolved Gas Supersaturation on Turbine-Passed Fish"  

SciTech Connect

Migratory and resident fish in the Columbia River Basin are exposed to stresses associated with hydroelectric power production, including pressure changes during turbine passage. The responses of fall chinook salmon and bluegill sunfish to rapid pressure change was investigated at the Pacific Northwest National Laboratory. Previous test series evaluated the effects of passage through a vertical Kaplan turbine under the"worst case" pressure conditions and under less severe conditions where pressure changes were minimized. For this series of tests, pressure changes were modified to simulate passage through a horizontal bulb turbine, commonly installed at low head dams. The results were compared to results from previous test series. Migratory and resident fish in the Columbia River Basin are exposed to stresses associated with hydroelectric power production, including pressure changes during turbine passage. The responses of fall chinook salmon and bluegill sunfish to rapid pressure change was investigated at the Pacific Northwest National Laboratory. Previous test series evaluated the effects of passage through a vertical Kaplan turbine under the"worst case" pressure conditions and under less severe conditions where pressure changes were minimized. For this series of tests, pressure changes were modified to simulate passage through a horizontal bulb turbine, commonly installed at low head dams. The results were compared to results from previous test series. Both fish species were acclimated for 16-22 hours at either surface (101 kPa; 1 atm) or 30 ft (191 kPa; 1.9 atm) of pressure in a hyperbaric chamber before exposure to a pressure scenario simulating passage through a horizontal bulb turbine. The simulation was as follows: gradual pressure increase to about 2 atm of pressure, followed by a sudden (0.4 second) decrease in pressure to either 0.7 or 0.95 atm, followed by gradual return to 1 atm (surface water pressure). Following the exposure, fish were held at surface pressure for a 48-hour post exposure observation period. No fall chinook salmon died during or after exposure to the horizontal bulb turbine passage pressures, and no injuries were observed during the 48-hour post exposure observation period. As with the previous test series, it cannot be determined whether fall chinook salmon acclimated to the greater water pressure during the pretest holding period. For bluegill sunfish exposed to the horizontal bulb turbine turbine-passage pressures, only one fish died and injuries were less severe and less common than for bluegills subjected to either the"worst case" pressure or modified Kaplan turbine pressure conditions in previous tests. Injury rates for bluegills were higher at 0.7 atm nadir than for the 0.95 atm nadir. However, injuries were limited to minor internal hemorrhaging. Bluegills did not suffer swim bladder rupture in any tested scenarios. Tests indicated that for most of the cross-sectional area of a horizontal bulb turbine, pressure changes occurring during turbine passage are not harmful to fall chinook salmon and only minimally harmful to bluegill. However, some areas within a horizontal bulb turbine may have extreme pressure conditions that would be harmful to fish. These scenarios were not tested because they represent a small cross-sectional area of the turbine compared to the centerline pressures scenarios used in these tests.

Abernethy, Cary S. (BATTELLE (PACIFIC NW LAB)); Amidan, Brett G. (BATTELLE (PACIFIC NW LAB)); Cada, G F. (ORNL)

2003-07-31

220

Fuel Mystery Dis-Solved!  

NSDL National Science Digital Library

In this activity, students investigate the simulated use of solid rocket fuel by using an antacid tablet. Students observe the effect that surface area and temperature has on chemical reactions. Also, students compare the reaction time using two different reactants: water and vinegar. Finally, students report their results using a bar graph.

Integrated Teaching And Learning Program

221

Design/installation and structural integrity assessment of Bethel Valley low-level waste collection and transfer system upgrade for Building 3092 (Central Off-Gas Scrubber Facility) at Oak Ridge National Laboratory  

SciTech Connect

This document describes and assesses planned modifications to be made to the Building 3092 Central Off-Gas Scrubber Facility of the Oak Ridge National Laboratory, Oak Ridge, Tennessee. The modifications are made in responsible to the requirements of 40CFR264 Subpart J, relating to environmental protection requirements for buried tank systems. The modifications include the provision of a new scrubber recirculation tank in a new, below ground, lines concrete vault, replacing and existing recirculation sump that does not provide double containment. A new buried, double contained pipeline is provided to permit discharge of spent scrubber recirculation fluid to the Central Waste Collection Header. The new vault, tank, and discharge line are provided with leak detection and provisions to remove accumulated liquid. New scrubber recirculation pumps, piping, and accessories are also provided. This assessment concludes that the planned modifications comply with applicable requirements of 40CFR264 Subpart J, as set forth in Appendix F to the Federal Facility Agreement, Docket No. 89-04-FF, covering the Oak Ridge Reservation.

NONE

1995-01-01

222

Design/Installation and Structural Integrity Assessment of Bethel Valley Low-Level Waste collection and transfer system upgrade for Building 3092 (central off-gas scrubber facility) at Oak Ridge National Laboratory  

SciTech Connect

This document describes and assesses planned modifications to be made to the Building 3092 Central Off-Gas Scrubber Facility of the Oak Ridge National Laboratory, Oak Ridge, Tennessee. The modifications are made in response to the requirements of 40CFR264 Subpart J, relating to environmental protection requirements for buried tank systems. The modifications include the provision of a new scrubber recirculation tank in a new, below ground, lined concrete vault, replacing an existing recirculation sump that does not provide double containment. A new buried, double contained pipeline is provided to permit discharge of spent scrubber recirculation fluid to the Central Waste Collection Header. The new vault, tank, and discharge line are provided with leak detection and provisions to remove accumulated liquid. Ne scrubber recirculation pumps, piping, and accessories are also provided. This assessment concludes that the planned modifications comply with applicable requirements of 40CFR264 Subpart J, as set forth in Appendix F to the Federal Facility Agreement, Docket No. 89-04-FF, covering the Oak Ridge Reservation. A formal design certification statement is included herein on Page 53, a certification covering the installation shall be executed prior to placing the modified facility into service.

Not Available

1994-10-01

223

Photochemical flocculation of terrestrial dissolved organic matter and iron  

NASA Astrophysics Data System (ADS)

Dissolved organic matter (DOM) rich water samples (Great Dismal Swamp, Virginia) were 0.1-?m filtered and UV-irradiated in a solar simulator for 30 days. During the irradiation, pH increased, particulate organic matter (POM) and particulate iron formed. After 30 days, 7% of the dissolved organic carbon (DOC) was converted to POC while 75% was remineralized. Approximately 87% of the iron was removed from the dissolved phase after 30 days, but iron did not flocculate until a major fraction of DOM was removed by photochemical degradation and flocculation (>10 days); thus, during the initial 10 days, there were sufficient organic ligands present or the pH was low enough to keep iron in solution. Nuclear magnetic resonance and Fourier transform infrared spectroscopies indicated that photochemically flocculated POM was more aliphatic than the residual non-flocculated DOM. Photochemically flocculated POM was also enriched in amide functionality, while carbohydrate-like material was resistant to both photochemical degradation and flocculation. Abiotic photochemical flocculation likely removes a significant fraction of terrestrial DOM from the upper water column between headwaters and the ocean, but has previously been ignored. Preliminary evidence suggests that this process may significantly impact the transport of DOM and POM in ocean margin environments including estuaries.

Helms, John R.; Mao, Jingdong; Schmidt-Rohr, Klaus; Abdulla, Hussain; Mopper, Kenneth

2013-11-01

224

Removing Dissolved Inorganic Contaminants from Water.  

National Technical Information Service (NTIS)

Dissolved inorganic contaminants in water can be cationic, anionic, or neutral forms of ions, atoms, or molecules of any element in the periodic table. The article describes the physicochemical treatment processes typically used to remove the more common ...

D. Clifford T. J. Sorg S. Subramonian

1986-01-01

225

College Students' Awareness and Perceptions of Dissolvable ...  

Center for Biologics Evaluation and Research (CBER)

Text VersionCollege Students' Awareness and Perceptions of Dissolvable Tobacco Products ... o Risk Perception ... To measure trajectories of SLT use among ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

226

Photo-lability of deep ocean dissolved black carbon  

NASA Astrophysics Data System (ADS)

Dissolved black carbon (DBC), defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzene polycarboxylic acid oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC) pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance) were determined over the course of a 28 d irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 164 nM C to 55 15 nM C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 yr. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Photo-degradation is therefore posited as the primary sink for oceanic DBC and the survival of DBC molecules in the oceans for millennia appears to be facilitated not by their inherent inertness but by the rate at which they are cycled through the surface ocean's photic zone.

Stubbins, A.; Niggemann, J.; Dittmar, T.

2012-01-01

227

Dissolved-Solids Load in Henrys Fork Upstream from the Confluence with Antelope Wash, Wyoming, Water Years 1970-2009  

USGS Publications Warehouse

Annual dissolved-solids load at the mouth of Henrys Fork was estimated by using data from U.S. Geological Survey streamflow-gaging station 09229500, Henrys Fork near Manila, Utah. The annual dissolved-solids load for water years 1970-2009 ranged from 18,300 tons in 1977 to 123,300 tons in 1983. Annual streamflows for this period ranged from 14,100 acre-feet in 1977 to 197,500 acre-feet in 1983. The 25-percent trimmed mean dissolved-solids load for water years 1970-2009 was 44,300 tons per year at Henrys Fork near Manila, Utah. Previous simulations using a SPAtially Referenced Regression On Watershed attributes (SPARROW) model for dissolved solids specific to water year 1991 conditions in the Upper Colorado River Basin predicted an annual dissolved-solids load of 25,000 tons for the Henrys Fork Basin upstream from Antelope Wash. On the basis of computed dissolved-solids load data from Henrys Fork near Manila, Utah, together with estimated annual dissolved-solids load from Antelope Wash and Peoples Canal, this prediction was adjusted to 37,200 tons. As determined by simulations with the Upper Colorado River Basin SPARROW model, approximately 56 percent (14,000 tons per year) of the dissolved-solids load at Henrys Fork upstream from Antelope Wash is associated with the 21,500 acres of irrigated agricultural lands in the upper Henrys Fork Basin.

Foster, Katharine; Kenney, Terry A.

2010-01-01

228

Suspended sediment, dissolved organic carbon, and dissolved nitrogen export during the dam removal process  

Microsoft Academic Search

(1) Total suspended solids (TSS), dissolved organic carbon (DOC), and total dissolved nitrogen (TDN) loads were calculated for all stages of the dam removal process (dewatering, breaching, and removal) at various points upstream, within, and downstream of Lowell Mill Impoundment on the Little River, North Carolina. The impoundment dewatering exported loads of TSS, DOC, and TDN which were all 1-2

J. Adam Riggsbee; Jason P. Julian; Martin W. Doyle; Robert G. Wetzel

2007-01-01

229

Stormflow Dynamics of Dissolved Organic Carbon and Total Dissolved Nitrogen in a Small Urban Watershed  

Microsoft Academic Search

We examined patterns of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) loading to a small urban stream during baseflow and stormflow. We hypothesized that lower DOC and TDN contributions from impervious surfaces would dilute natural hydrologic flowpath (i.e., riparian) contributions during storm events in an urban watershed, resulting in lower concentrations of DOC and TDN during storms. We

Aaron M. Hook; J. Alan Yeakley

2005-01-01

230

Developing Standards for Dissolved Iron in Seawater  

NASA Astrophysics Data System (ADS)

In nearly a dozen open-ocean fertilization experiments conducted by more than 100 researchers from nearly 20 countries, adding iron at the sea surface has led to distinct increases in photosynthesis rates and biomass. These experiments confirmed the hypothesis proposed by the late John Martin that dissolved iron concentration is a key variable that controls phytoplankton processes in ocean surface waters. However, the measurement of dissolved iron concentration in seawater remains a difficult task with significant interlaboratory differences apparent at times. The availability of a seawater reference solution with well-known dissolved iron (Fe) concentrations similar to open-ocean values, which could be used for the calibration of equipment or other tasks, would greatly alleviate these problems.

Johnson, Kenneth S.; Boyle, Edward; Bruland, Kenneth; Coale, Kenneth; Measures, Chris; Moffett, James; Aguilar-Islas, Ana; Barbeau, Katherine; Bergquist, Bridget; Bowie, Andrew; Buck, Kristen; Cai, Yihua; Chase, Zanna; Cullen, Jay; Doi, Takashi; Elrod, Virginia; Fitzwater, Steve; Gordon, Michael; King, Andrew; Laan, Patrick; Laglera-Baquer, Luis; Landing, William; Lohan, Maeve; Mendez, Jeffrey; Milne, Angela; Obata, Hajime; Ossiander, Lia; Plant, Joshua; Sarthou, Geraldine; Sedwick, Peter; Smith, Geoffrey J.; Sohst, Bettina; Tanner, Sara; Van den Berg, Stan; Wu, Jingfeng

2007-03-01

231

Dissolved Organic Metals in the Hydrothermal Plume  

NASA Astrophysics Data System (ADS)

In the hydrothermal plume, there are the unique microbiological communities and the microorganism utilizes various chemical substances. The interactions between heavy metals and microorganisms in the hydrothermal plume are important to comprehend the oceanic geochemical cycles of heavy metals. It is considered that the heavy metals in hydrothermal plume are organically bound with dissolved organic matter derived from the hydrothermal microorganism. This study funded by the O`Archaean ParkO_L project of MEXT is a first attempt to observe the bioavailability of heavy metals in hydrothermal plume. The hydrothermal plume samples were taken from two different kinds of hydrothermal sites, the Suiyo Seamount caldera and the Central Indian Ridge. The mini CTDT-RMS mounted twelve 1.2L Niskin bottles was installed on the manned submersible, and the hydrothermal plume samples were collected by taking the distance from the hydrothermal vents gradually. The solid phase extraction technique in C18 Sep-Pak cartridge (Millipore Waters) was used to extract the dissolved organic matter from the hydrothermal plume samples. Dissolved heavy metals (Al, Mn, Fe, Cu, Zn, Co, Ni, As, Mo, Cd and Pb) bound with C18 Sep-Pak extractable organic matter, dissolved organic metals, were analyzed by GFAAS. In all measured heavy metals, the dissolved organic metals existed in the hydrothermal plume samples collected from two sites. The concentration of the dissolved organic metals ranged from 0.5nM to 30nM and was about 1/1000~1/100 of the total dissolved heavy metals concentration. It suggests that these heavy metals were bound with organic matter originated in the hydrothermal microorganism. Though the abundance of the organism in the Central Indian Ridge is larger than that in the Suiyo Seamount caldera, the concentration of the dissolved organic metals in the plume samples at the Suiyo Seamount caldera was higher than that at the Central Indian Ridge. These results indicate that the bioavailability of heavy metals is different in two sites.

Shitashima, K.

2003-12-01

232

Dissolved oxygen control of the activated sludge wastewater treatment process using stable adaptive fuzzy control  

Microsoft Academic Search

In the operation of wastewater treatment plants a key variable is dissolved oxygen (DO) content in the bioreactors. The paper describes the development of an adaptive fuzzy control strategy for tracking the DO reference trajectory applied to the Benchmark Simulation Model n.1. The design methodology of this data-driven controller uses the Lyapunov synthesis approach with a parameter projection algorithm to

Carlos Alberto Coelho Belchior; Rui Alexandre Matos Arajo; Jorge Afonso Cardoso Landeck

233

Predicting and managing risk of unsuitable dissolved oxygen in a eutrophic lake  

Microsoft Academic Search

Eutrophication of lakes is often accompanied by wide diel fluctuations in dissolved oxygen (DO) concentrations that can influence fish assemblage composition and periodically result in highly visible fish kills. We conducted a probabilistic risk assessment to estimate the likelihood that a shallow eutrophic oxbow lake would be affected by critically low DO concentration at dawn during mid-summer. Monte-Carlo simulations with

L. E. Miranda; J. A. Hargreaves; S. W. Raborn

2001-01-01

234

Assessment of best management practices for improvement of dissolved oxygen in Chesapeake Bay estuary  

Microsoft Academic Search

Abtract Two management scenarios, the base case and the full voluntary program implementation scenarios, are simulated with the three-dimensional Chesapeake Bay estuary model package to study the improvement of dissolved oxygen (DO) over the bay in response to the reduction of nutrient loads. The base case scenario is based on the 1985 nutrient management practices and the associated loads from

P. Wang; R. Batiuk; L. Linker; G. Shenk

2001-01-01

235

Dissolved Nutrient Retention Dynamics in River Networks: A Modeling Investigation of Transient Flow and Scale Effects  

Microsoft Academic Search

In this paper, we use a dynamic network flow model, coupled with a transient storage zone biogeochemical model, to simulate dissolved nutrient removal processes at the channel network scale. We have explored several scenarios in respect of the combination of rainfall variability, and the biological and geomorphic characteristics of the catchment, to understand the dominant controls on removal and delivery

Sheng Ye; Timothy P. Covino; Murugesu Sivapalan; Nandita Basu; Hongyi Li; Shaowen Wang

2012-01-01

236

A novel approach to controlling dissolved oxygen levels in laboratory experiments  

Microsoft Academic Search

Hypoxia is a widespread environmental stressor that affects marine, estuarine and freshwater systems worldwide. Investigating the effects of hypoxia on aquatic animals in the natural environment is difficult and expensive. Laboratory experiments provide an alternative that allows manipulation of environmental variables and simulation of altered conditions that are expected in the future. However, controlling dissolved oxygen (DO) levels precisely in

K. L. Hassell; P. C. Coutin; D. Nugegoda

2009-01-01

237

Accumulation of dissolved and colloidal substances in water recycled during papermaking  

Microsoft Academic Search

As fresh water consumption in pulp and paper industry processes is reduced, dissolved and colloidal substances (DCS) gradually accumulate, which has a serious adverse impact on the production and quality of the paper product. Using laboratory simulations of the recycling filtration process of papermaking, we have studied changes in different water quality parameters with the increasing amount of water recycling

Liang Jidong; He Yanling; Zhu Jinwei; Du Wenjing

2011-01-01

238

TRANSPORT OF DISSOLVED ORGANICS FROM DILUTE AQUEOUS SOLUTIONS THROUGH FLEXIBLE MEMBRANE LINERS  

EPA Science Inventory

This paper presents the results of experiments relating to the partitioning of dissolved organics from dilute aqueous solutions to polymeric flexihle memhrane liner (FMLs) and their permeation through these liners. n order to simulate partitioning and the transport of waste const...

239

Identification of Dissolved-Constituent Sources in Mine-Site Ground Water Using Batch Mixing  

NASA Astrophysics Data System (ADS)

Batch-mixing experiments were used to help identify lithologic and mineralogic sources of increased concentrations of dissolved solids in water affected by surface coal mining in northwestern Colorado. Ten overburden core samples were analyzed for mineral composition and mixed with distilled water for 90 days until mineral-water equilibrium was reached. Between one day and 90 days after initial contact, specific conductance in the sample mixtures had a median increase of 306 percent. Dissolved-solids concentrations ranged from 200 to 8,700 mg/L in water samples extracted from the mixtures after 90 days. Mass-balance simulations were conducted using the geochemical models BALANCE and WATEQF to quantify mineral-water interactions occurring in five selected sample mixtures and in water collected from a spring at a reclaimed mine site. The spring water is affected by mineral-water interactions occurring in all of the lithologic units comprising the overburden. Results of the simulations indicate that oxidation of pyrite, dissolution of dolomite, gypsum, and epsomite, and cation-exchange reactions are the primary mineral-water interactions occurring in the overburden. Three lithologic units in the overburden (a coal, a sandstone, and a shale) probably contribute most of the dissolved solids to the spring water. Water sample extracts from mixtures using core from these three units accounted for 85 percent of the total dissolved solids in the 10 sample extracts. Other lithologic units in the overburden probably contribute smaller quantities of dissolved solids to the spring water.

Clark, Gregory M.; Williams, Robert S., Jr.

1991-02-01

240

EXPERIMENTAL STUDY TO EVALUATE CORROSION OF THE F-CANYON DISSOLVER DURING THEUNIRRADIATED MARK-42 CAMPAIGN  

SciTech Connect

Unirradiated Mark 42 fuel tubes are to be dissolved in an upcoming campaign in F-canyon. Savannah River Technology Center (SRTC)/Chemical & Hydrogen Technology Section (CHTS) identified a flow sheet for the dissolution of these Mark 42 fuel tubes which required a more aggressive dissolver solution than previously required for irradiated Mark 42 fuel tubes. Subsequently, SRTC/MTS was requested to develop and perform a corrosion testing program to assess the impact of new flow sheets on corrosion of the dissolver wall. The two primary variables evaluated were the fluoride and aluminum concentrations of the dissolver solution. Fluoride was added as Calcium Fluoride (CaF{sub 2}) while the aluminum was added either as metallic aluminum, which was subsequently dissolved, or as the chemical aluminum nitrate (Al(NO{sub 3}){sub 3}). The dissolved aluminum metal was used to simulate the dissolution of the aluminum from the Mark 42 cladding and fuel matrix. Solution composition for the corrosion tests bracketed the flow sheet for the Mark 42. Corrosion rates of AISI Type 304 stainless steel coupons, both welded and non-welded coupons, were calculated from measured weight losses and post-test concentrations of soluble Fe, Cr and Ni. The corrosion rates, which ranged between 2.7 and 32.5 mpy, were calculated from both the one day and the one week weight losses. These corrosion rates indicated a relatively mild corrosion on the dissolver vessel. The welded coupons consistently had a higher corrosion rate than the non-welded coupons. The difference between the two decreased as the solution aggressiveness decreased. In these test solutions, aggressiveness corresponded with the fluoride concentration. Based on the results of this study, any corrosion occurring during the Mark 42 Campaign is not expected to have a deleterious effect on the dissolver vessel.

Mickalonis, J; Kerry Dunn, K

1999-08-01

241

Control of Dissolved Oxygen in Stirred Bioreactors  

Microsoft Academic Search

This report discusses control of dissolved oxygen in a biore actor where the oxygen supply is manipulated using the stirrer speed. In batch and fedbatch cultivations the operating conditions change signifi cantly which may cause tuning problems. Analysis using a linearized pro cess model shows that the process dynamics is mainly affected by changes in the volumetric oxygen transfer coefficient

Mats kesson Per Hagander

242

REMOVING DISSOLVED INORGANIC CONTAMINANTS FROM WATER  

EPA Science Inventory

Dissolved inorganic contaminants in water can be cationic, anionic, or neutral forms of ions, atoms, or molecules of any element in the periodic table. The article describes the physicochemical treatment processes typically used to remove the more common inorganic contaminants fr...

243

Dissolved zirconium in the north Pacific Ocean  

SciTech Connect

Picomolar levels of dissolved Zr in seawater were measured using an analytical technique developed with a Chelex-100 extraction/concentration step and subsequent detection by isotope-dilution inductively-coupled-plasma mass spectrometry (ID-ICP-MS). Here the authors present the first vertical profile of Zr in the oceans, from the central-North Pacific, and a horizontal surface transect across the western Pacific. Dissolved Zr ranges from 12--95 pmol/kg in the surface waters then increases linearly with depth to a maximum of 300 pmol/kg in the deep water. The vertical profile shows a strong correlation with Si in the mid-waters, with higher Zr/Si ratios in the surface and bottom waters. There is evidence of both a bottom source and a coastal source of dissolved Zr to the oceans. A comparison with dissolved Ti and Be shows similar depth dependence, but an enrichment in Zr/Ti and a depletion in Zr/Be ratios in seawater relative to average crustal materials. Zirconium appears to have a reactivity intermediate between these two elements. 24 refs., 4 figs., 1 tab.

McKelvey, B.A.; Orians, K.J. (Univ. of British Columbia, Vancouver (Canada))

1993-08-01

244

Dissolved silver in the Baltic Sea  

Microsoft Academic Search

The increased use of silver as a biocide in nanoparticle formulations has heightened concern on possible environmental implications owing to its toxicity. There is however very little data on the concentration levels of silver in marine and freshwaters. Here, I report data on dissolved (<0.4?m filter) silver concentration in the surface waters of the Baltic Sea, the first such data

Kuria Ndungu

2011-01-01

245

DISSOLVED OXYGEN IMPACT FROM URBAN STORM RUNOFF  

EPA Science Inventory

The primary objective of the research reported here is to determine if on a national basis a correlation exists between strength of dissolved oxygen (DO) deficits and the presence of rainfall and/or storm runoff downstream of urban areas. A secondary objective is to estimate the ...

246

Progress in dissolving modified LEU Cintichem targets.  

National Technical Information Service (NTIS)

A process is under development to use low-enriched uranium (LEU) metal targets for production of (sup 99)Mo. The first step is to dissolve the irradiated foil. In past work, this has been done by heating a closed (sealed) vessel containing the foil and a ...

R. A. Leonard L. Chen C. J. Mertz G. F. Vandegrift

1996-01-01

247

Bubble Dissolving in Turbulent Pipe Flow.  

National Technical Information Service (NTIS)

Measurements are presented of bubble dissolving in turbulent pipe flow at pipe Reynolds numbers of 2xlO4, lxlO5 and 2xlO5, based on pipe diameter. The mass transfer coefficient is determined and it increases with Reynolds number. The coefficient appears t...

S. Gowing

1992-01-01

248

Dissolved vanadium in rivers and estuaries  

NASA Astrophysics Data System (ADS)

New measurements of dissolved vanadium in a variety of rivers and estuaries are presented here. The data indicate that the average concentration of dissolved vanadium in major rivers entering the ocean is 15 nmol/kg. Weathering rate and type of source rock, rather than solution chemistry or anthropogenic influences, appear to be the important factors in determining fluvial dissolved vanadium concentrations. Laboratory experiments suggest that in oxic waters vanadium is found predominantly in its most oxidized, anionic form (V(V)). Complexation with organic matter and formation of large colloidal species appear to be unimportant. Adsorption also appears to be a less important influence for vanadium than for some other trace elements such as zinc. In estuaries, vanadium behaves as a bioactive element, showing a close correspondence with the distribution of phosphate. The extent of estuarine vanadium removal is presently uncertain but may be low due to rapid remineralization of this element. Based on the river flux, the oceanic residence time for dissolved vanadium is estimated to be 100,000 years.

Shiller, Alan M.; Boyle, Edward A.

1987-12-01

249

Developing Standards for Dissolved Iron in Seawater  

Microsoft Academic Search

In nearly a dozen open-ocean fertilization experiments conducted by more than 100 researchers from nearly 20 countries, adding iron at the sea surface has led to distinct increases in photosynthesis rates and biomass. These experiments confirmed the hypothesis proposed by the late John Martin that dissolved iron concentration is a key variable that controls phytoplankton processes in ocean surface waters.

Kenneth S. Johnson; Edward Boyle; Kenneth Bruland; Kenneth Coale; Chris Measures; James Moffett; Ana Aguilar-Islas; Katherine Barbeau; Bridget Bergquist; Andrew Bowie; Kristen Buck; Yihua Cai; Zanna Chase; Jay Cullen; Takashi Doi; Virginia Elrod; Steve Fitzwater; Michael Gordon; Andrew King; Patrick Laan; Luis Laglera-Baquer; William Landing; Maeve Lohan; Jeffrey Mendez; Angela Milne; Hajime Obata; Lia Ossiander; Joshua Plant; Geraldine Sarthou; Peter Sedwick; Geoffrey J. Smith; Bettina Sohst; Sara Tanner; Stan Van den Berg; Jingfeng Wu

2007-01-01

250

Dissolved zirconium in the North Pacific Ocean  

NASA Astrophysics Data System (ADS)

Picomolar levels of dissolved Zr in seawater were measured using an analytical technique developed with a Chelex-100 extraction/concentration step and subsequent detection by isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). Here we present the first vertical profile of Zr in the oceans, from the central-North Pacific, and a horizontal surface transect across the western Pacific. Dissolved Zr ranges from 12-95 pmol/kg in the surface waters then increases linearly with depth to a maximum of 300 pmol/kg in the deep water. The vertical profile shows a strong correlation with Si in the mid-waters, with higher Zr/Si ratios in the surface and bottom waters. There is evidence of both a bottom source and a coastal source of dissolved Zr to the oceans. A comparison with dissolved Ti and Be shows similar depth dependence, but an enrichment in Zr/Ti and a depletion in Zr/Be ratios in seawater relative to average crustal materials. Zirconium appears to have a reactivity intermediate between these two elements.

McKelvey, Brad A.; Orians, Kristin J.

1993-08-01

251

Development and use of sintered metal filters with fluidized bed and spray calcination of simulated high-level waste  

Microsoft Academic Search

Sintered metal filters have been used for off-gas particulate removal on a pilot-scale fluidized bed calciner and spray calciner. The units calcined simulated commercial HLW at rates equivalent to 1 to 3 MTU\\/day fuel reprocessed. Filters were cleaned by a periodic pulse of air in a reverse direction through the filters. Filter systems design and recommended operating parameters are described.

Bjorklund

1976-01-01

252

Can hydrate form in carbon dioxide from dissolved water?  

PubMed

Transport of carbon dioxide in offshore pipelines involves high pressures and low temperatures, which may lead to formation of hydrate from the residual dissolved water and carbon dioxide. While thermodynamics is able to tell us whether the hydrate phase will be stable, the question of whether its formation will actually occur under given pipeline conditions does not have a straightforward answer. In this work, we have made use of water properties obtained from molecular simulations to examine the thermodynamics of hydrate formation from water dissolved in carbon dioxide. This paper proposes a method that allows estimation of absolute thermodynamic properties and thus makes it possible to compare free energy changes due to several possible phase transitions and determine the most probable transition. This information can be used directly to choose the optimum hydrate prevention strategy. We have found that hydrate formation from a carbon dioxide solution will be thermodynamically viable at water concentration exceeding a certain level; a conclusion also supported by several previous studies. We have also extended the quantitative analysis of the thermodynamics and the kinetics of formation through a modified version of phase field theory (PFT). The work presents the way to obtain parameters required for the practical implementation of the PFT in the case of hydrate formation, as well as outlines the estimation of thermodynamic properties for systems unable to reach true equilibrium. PMID:23264960

Kvamme, Bjrn; Kuznetsova, Tatiana; Kivel, Pilvi-Helina; Bauman, Jordan

2012-12-21

253

Evaluation and Testing of IONSIV IE-911 for the Removal of Cesium-137 from INEEL Tank Waste and Dissolved Calcines  

SciTech Connect

Development of waste treatment processes for the remediation of radioactive wastes is currently underway. A number of experiments were performed at the Idaho Nuclear Technology and Environmental Center (INTEC) located at the Idaho National Engineering and Environmental Laboratory (INEEL) with the commercially available sorbent material, IONSIV IE-911, crystalline silicotitanate (CST), manufactured by UOP LLC. The purpose of this work was to evaluate the removal efficiency, sorbent capacity and selectivity of CST for removing Cs-137 from actual and simulated acidic tank waste in addition to dissolved pilot-plant calcine solutions. The scope of this work included batch contact tests performed with non-radioactive dissolved Al and Run-64 pilot plant calcines in addition to simulants representing the average composition of tank waste. Small-scale column tests were performed with actual INEEL tank WM-183 waste, tank waste simulant, dissolved Al and Run-64 pilot plant calcine solutions. Small-scale column experiments using actual WM-183 tank waste resulted in fifty-percent Cs-137 breakthrough at approximately 589 bed volumes. Small-scale column experiments using the tank waste simulant displayed fifty-percent Cs-137 breakthrough at approximately 700 bed volumes. Small-scale column experiments using dissolved Al calcine simulant displayed fifty-percent Cs-137 breakthrough at approximately 795 bed volumes. Column experiments with dissolved Run-64, pilot plant calcine did not reach fifty-percent breakthrough throughout the test.

N. R. Mann; T. A. Todd; K. N. Brewer; D. J. Wood; T. J. Tranter; P. A. Tullock

1999-04-01

254

Photo-lability of deep ocean dissolved black carbon  

NASA Astrophysics Data System (ADS)

Dissolved black carbon (DBC), defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzenepolycarboxylic acid (BPCA) oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC) pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance) were determined over the course of a 28 day irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 164 nM-C to 55 15 nM-C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. The concentration of DBC correlated with CDOM absorbance and the quality of DBC indicated by the ratios of different BPCAs correlated with CDOM absorbance spectral slope, suggesting the optical properties of CDOM may provide a proxy for both DBC concentrations and quality in natural waters. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 years. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Consequently, photo-degradation is posited as the primary sink for oceanic DBC and the apparent survival of DBC molecules in the oceans for millennia appears to be facilitated not by their inherent inertness but by the rate at which they are cycled through the surface ocean's photic zone.

Stubbins, A.; Niggemann, J.; Dittmar, T.

2012-05-01

255

Upper ocean model of dissolved atmospheric gases  

SciTech Connect

The goal of this project is to estimate the rate of biological oxygen production at Hawaiian Ocean Time-series station ALOHA in the central North Pacific ocean. Our approach is to use an upper ocean model together with measurements to interpret an annual cycle of temperature, salinity, dissolved oxygen, argon, nitrogen, and the stable isotope ratio of oxygen at station ALOHA. This project represents the first upper ocean geochemical study in which model predictions are verifiable by independent measurements. Using the model, we will be able to assess the relative roles played by physical processes (air-sea gas exchange, air injection by bubbles, temperature-induced changes in gas solubility, trapping below the mixed layer, and diffusion) and biological processes (photosynthesis, respiration, and nutrient recycling) in producing the observed distribution of dissolved atmospheric gases. The long term goal of this project is to understand the utility of chemical tracers for quantifying biological processes in the ocean.

Schudlich, R.; Emerson, S.

1992-01-01

256

Method of dissolving organic filter cake  

SciTech Connect

A method of dissolving a polysaccharide-containing filter cake present in a subterranean formation is described, comprising: injecting an effective amount of a treatment fluid comprising a water soluble source of fluoride ions present in an amount sufficient to provide a molar concentration of from about 0.01 to about 0.5 and a source of hydrogen ions present in an amount sufficient to produce a pH in the treatment fluid in the range of from about 2 to about 4 into a subterranean formation wherein a filter cake is present; and maintaining the treatment fluid within the subterranean formation and in contact with the filter cake for a sufficient time to dissolve at least a portion of the filter cake.

Hollenbeck, K.H.; Norman, L.R.

1989-03-07

257

Dissolved silver in the Baltic Sea.  

PubMed

The increased use of silver as a biocide in nanoparticle formulations has heightened concern on possible environmental implications owing to its toxicity. There is however very little data on the concentration levels of silver in marine and freshwaters. Here, I report data on dissolved (<0.4 ?m filter) silver concentration in the surface waters of the Baltic Sea, the first such data reported for a European coastal water body. Levels of dissolved silver in the Baltic are comparable to those reported for other American estuarine waters and range from non-detectable in the open Baltic Sea Proper (<1 pM) to 9.4 pM (1 ng/L) in the Stockholm Archipelago, with a mean of 2.8 pM (0.2 ng/L). Inputs from wastewater treatment are clearly discernable and might constitute the main source of silver to the Stockholm Archipelago and possibly the Baltic Sea Proper. PMID:21075364

Ndungu, Kuria

2010-11-13

258

Partial nitrification under limited dissolved oxygen conditions  

Microsoft Academic Search

Partial nitrification to nitrite is technically feasible and economically favourable, especially when wastewaters contained high ammonium concentrations or low C\\/N ratios. Partial nitrification can be obtained by selectively inhibiting nitrite-oxidizing bacteria (NOB) through appropriate regulation of the pH, temperature and dissolved oxygen (DO) concentrations. The effect of pH, DO levels and temperature on ammonia oxidation rate and nitrite accumulation was

Wang Jianlong; Yang Ning

2004-01-01

259

Distribution of dissolved silver in marine waters  

NASA Astrophysics Data System (ADS)

Silver is one of the most toxic heavy metals, surpassed only by mercury [1-3]. Monitoring of dissolved silver concentrations in natural waters is therefore of great importance. The determination of dissolved silver in waters is not without challenges, because of its low (picomolar) concentrations. Consequently, there are only a few reported studies in marine waters, which have been performed in USA [4-6] and Japan [7]. The analytical techniques used in the reported studies for the determination of silver in seawater were Graphite Furnace Atomic Absorption Spectroscopy (GFAAS) after solvent extraction [2,4,5], and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) after solvent extraction or solid phase extraction [7,8]. In this contribution, we will present an optimised Magnetic Sector (MS) ICP-MS technique for the determination of dissolved silver in marine waters. The MS-ICP-MS method used anion exchange column to preconcentrate silver from saline waters, and to remove the saline matrix. The ICP-MS method has been used successfully to determine total dissolved silver in estuarine and oceanic samples. Bibliography 1. H. T. Ratte, Environ. Toxicol. Chem. 1999, 18: p. 89-108. 2. R. T. Herrin, A. W. Andren and D. E. Armstrong, Environ. Sci. Technol. 2001, 35: 1953-1958. 3. D. E. Schildkraut, P. T. Dao, J. P. Twist, A. T. Davis and K. A. Robillard, Environ. Toxicol. Chem. 1998, 17: 642-649. 4. E. Breuer, S. A. Sanudo-Wilhelmy and R. C. Aller, Estuaries. 1999, 22:603-615. 5. A. R. Flegal, S. A. Sanudowilhelmy and G. M. Scelfo, Mar. Chem. 1995, 49: 315-320. 6. S. N. Luoma, Y. B. Ho and G. W. Bryan, Mar. Pollut. Bull. 1995, 31: 44-54. 7. Y. Zhang, H. Amakawa and Y. Nozaki, Mar. Chem. 2001, 75: 151-163. 8. L. Yang and R. E. Sturgeon, J. Anal. At. Spectrom. 2002, 17: 88-93.

Barriada, J. L.; Achterberg, E. P.; Tappin, A.; Truscott, J.

2003-04-01

260

Fast dissolving films made of maltodextrins  

Microsoft Academic Search

This work aimed to study maltodextrins (MDX) with a low dextrose equivalent as film forming material and their application in the design of oral fast-dissolving films. The suitable plasticizer and its concentration were selected on the basis of flexibility, tensile strength and stickiness of MDX films, and the MDX\\/plasticizer interactions were investigated by ATR-FTIR spectroscopy. Flexible films were obtained by

Francesco Cilurzo; Irma E. Cupone; Paola Minghetti; Francesca Selmin; Luisa Montanari

2008-01-01

261

Dissolved gases in seawater and sediments  

Microsoft Academic Search

Certainly the most controversial results derived from the study of any dissolved gas concerned oxygen utilization rates in the North Atlantic. Jenkins (1982) estimated a net oxy- gen utilization rate (OUR) for the Beta triangle region of the North Atlantic (apices 26.5N x 38.5W, 32.5N x 30.0W, and 22.5N x 28.5W) of 5.7 moles of oxygen consumed m?2 yr?1 for

R. M. Key

1987-01-01

262

Dissolved oxygen and the scleroglucan fermentation process  

Microsoft Academic Search

The effect of culture dissolved oxygen (D.O.) upon biomass, scleroglucan and oxalate formation bySclerotium glucanicum was examined in a stirred tank fermenter by oxygen enrichment. Controlling culture D.O. at 5 or 10% saturation led to increased biomass formation and decreased scleroglucan formation. The mechanism by which this occurred probably involved a non-specific diversion of C source (sucrose) away from product

Y. Wang; B McNeil

1995-01-01

263

Microbial degradation of dissolved proteins in seawater  

Microsoft Academic Search

An experimental protocol using radiolabeled proteins was developed to investigate the rates and mechanisms whereby dissolved proteins are degraded in natural marine plankton communities. The results of field observations and laboratory experiments indicate that proteins are degraded by a particle-bound, thermolabile system, presumably bacteria-associated enzymes, with an apparent half-saturation constant of ca. 25 ..mu..g bovine serum albumin (BSA) per liter.

J. T. Hollibaugh; F. Azam

1983-01-01

264

How is dissolved iron produced and transported in the Amur River basin?  

NASA Astrophysics Data System (ADS)

Recent research showed that iron limits phytoplankton growth in the western subarctic Pacific and that significant part of it comes from the Amur River, which forms the boundary of China and Russia and finally flows into the Sea of Okhotsk. Our research group confirmed that the crucial processes of producing dissolved iron are reductive release of ferrous iron and formation of iron complex with organic compound in wetland. However, drastic conversion of wetland into cultivated land in China part during the last half of 20th century may have great impact on iron production in the future. To assess the land conversion impact on dissolved iron production, we constructed a semi-distributed hydrological model incorporating dissolved iron production mechanism. The model consists of two modules; one for dealing with the physical process that calculates runoff (TOP- RUNOFF), and the other for dissolved iron production process (TOP-FE). Performance level of TOP- RUNOFF without any calibration assessed by Nash and Sutcliff criteria against observed discharge at several points are fairly well except for catchments affected by anthropogenic impact such as dam. On the basis of TOP-RUNOFF, TOP-FE was formulated as a function of water content, organic compound, air temperature, and one parameter representing the degree of redox condition. Calculated values were compared with observed value at the several tens of points. The result shows that the model reached the level which can predict seasonal trend of dissolved iron concentration. However, the present model can not simulate abrupt increase of dissolved iron concentration which was observed at many points during the late 1990s. Possible reasons of this anomaly are now under consideration. At present, promising reasons are climate change and anthropogenic impact such as agricultural activity, but not yet resolved. Thus, to clarify unknown mechanism which governs the long-term trend of dissolved iron concentration is needed to improve predictability of our model.

Onishi, T.; Yoh, M.; Shibata, H.; Nagao, S.; Kawahigashi, M.

2008-12-01

265

Treatment of SRS Tank 48H Simulants Using Fenton's Reagent  

SciTech Connect

High-level-waste Tank 48H at the Savannah River Site (SRS) contains about 50,000 lb of tetraphenylborate (TPB), which must be destroyed to return the tank to active service. Laboratory-scale tests were conducted to evaluate the use of Fenton's Reagent (hydrogen peroxide and a metal catalyst) to treat simulants of the Tank 48H waste. Samples of the treated slurry and the off-gas were analyzed to determine the reaction products. Process parameters developed earlier by AEA Technology were used for these tests; namely (for 500 mL of waste simulant), reduce pH to 7.5 with nitric acid, heat to boiling, add hydrogen peroxide at 1 mL/min for 1 h, reduce pH to 3.5, and add the remaining peroxide at 2 mL/min. These parameters were developed to minimize the formation of tarry materials during the early part of the reaction and to minimize the concentration of total organic carbon in the final treated slurry. The treated samples contained low concentrations of total organic carbon (TOC) and no detectable TPB. Tests using a mixture of iron and copper salts as the Fenton's catalyst had a lower TOC concentration in the final treated slurry than did tests that used a copper-only catalyst. TPB is known to hydrolyze to benzene, particularly at high temperature and low pH, and copper is known to increase the rate of hydrolysis. Significant amounts of benzene were present in the off-gas from the tests, especially during the early portion of the treatment, indicating that the hydrolysis reaction was occurring in parallel with the oxidation of the TPB by Fenton's reagent. For the reaction conditions used in these tests, approximately equal fractions of the TPB were converted to benzene and carbon dioxide. Minimizing the formation of benzene is important to SRS personnel; however, this consideration was not addressed in the AEA-recommended parameters, since they did not analyze for benzene in the off-gas. Smaller amounts of carbon monoxide and other organics were also produced. One test used a simulant with much lower concentrations of salts, representing washed sludge, and this test produced much smaller amounts of benzene. The nitrite ions in the simulant were oxidized to nitrate, which would increase the amount of peroxide required to oxidize all of the organic carbon. Oxygen is the primary constituent of the off-gas produced from treatment of the samples.

Taylor, PA

2003-11-18

266

Dissolved organic carbon on Georges Bank  

NASA Astrophysics Data System (ADS)

Dissolved organic carbon (DOC) in sea water from Georges Bank was measured by a high temperature combustion/direct injection (HTC/DI) technique during the spring bloom period in April 1993. Concentrations in surface waters (72-85 ?M) and deep waters (54-56 ?M) were similar to DOC concentrations measured in the oligotrophic north-west Atlantic Ocean by a number of other investigators by various techniques. Although surface values for Chl- a concentrations ranged from 2 to 5 ?g l -1, NO 3- ranged from 3 to 9 ?M and particulate organic carbon (POC) concentrations ranged from 1.0 to 10?M, DOC concentrations only varied by <18 DOC was slightly higher (5 ?M) in the highly productive central bank region than in surrounding stratified surface waters. Relatively constant stable carbon isotopes (DO 13C = -22.0 0.5 could not be used to identify a source for these small variations. Slight decreases of DOC (5-12?M) and dissolved organic nitrogen (DON) (0.5-1.0 ?M) in filtered sea water kept in the dark was observed over six months, suggesting the presence of a small, labile pool of dissolved organic matter in addition to a large, more refractory reservoir of DOC (70 ?M) during the spring bloom period on Georges Bank.

Chen, Robert F.; Fry, Brian; Hopkinson, Chuck S.; Repeta, Daniel J.; Peltzer, Edward T.

1996-04-01

267

FINAL REPORT INTEGRATED DM1200 MELTER TESTING USING AZ 102 AND C 106/AY-102 HLW SIMULANTS: HLW SIMULANT VERIFICATION VSL-05R5800-1 REV 0 6/27/05  

SciTech Connect

The principal objectives of the DM1200 melter tests were to determine the effects of feed rheology, feed solid content, and bubbler configuration on glass production rate and off-gas system performance while processing the HLW AZ-101 and C-106/AY-102 feed compositions; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components, as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and perform pre- and post test inspections of system components. The specific objectives (including test success criteria) of this testing, along with how each objective was met, are outlined in a table. The data provided in this Final Report address the impacts of HLW melter feed rheology on melter throughput and validation of the simulated HLW melter feeds. The primary purpose of this testing is to further validate/verify the HLW melter simulants that have been used for previous melter testing and to support their continued use in developing melter and off-gas related processing information for the Project. The primary simulant property in question is rheology. Simulants and melter feeds used in all previous melter tests were produced by direct addition of chemicals; these feed tend to be less viscous than rheological the upper-bound feeds made from actual wastes. Data provided here compare melter processing for the melter feed used in all previous DM100 and DM1200 tests (nominal melter feed) with feed adjusted by the feed vendor (NOAH Technologies) to be more viscous, thereby simulating more closely the upperbounding feed produced from actual waste. This report provides results of tests that are described in the Test Plan for this work. The Test Plan is responsive to one of several test objectives covered in the WTP Test Specification for this work; consequently, only part of the scope described in the Test Specification was addressed in this particular Test Plan. For the purpose of comparison, the tests reported here were performed with AZ-102 and C-106/AY-102 HLW simulants and glass compositions that are essentially the same as those used for recent DM1200 tests. One exception was the use of an alternate, higher-waste-loading C-106/AY-102 glass composition that was used in previous DM100 tests to further evaluate the performance of the optimized bubbler configuration.

KRUGER AA; MATLACK KS; GONG W; BARDAKCI T; D'ANGELO NA; BRANDYS M; KOT WK; PEGG IL

2011-12-29

268

Uptake of allochthonous dissolved organic matter from soil and ...  

Treesearch

Title: Uptake of allochthonous dissolved organic matter from soil and salmon ... Description: Dissolved organic matter (DOM) is an important component of aquatic food ... DOC, DON, fluorescence, PARAFAC salmon, wetlands, nutrient uptake.

269

Danger from Dissolvable Tobacco and Other Tobacco Products  

MedlinePLUS

... market. In January 2009, R.J. Reynolds introduced Camel Orbs, Strips, and Sticks, its newest dissolvable, smokeless ... them), the novel configuration, packaging, and flavoring of Camels new dissolvables prompted Congress to include a requirement ...

270

Changes in dissolved organic matter with depth suggest the ...  

Treesearch

Research into postharvest management of forests often focuses on ... a strong influence over the translocation of carbon (C) into and through the soil ... Keywords: dissolved organic carbon, dissolved organic nitrogen, DOC:DON ratio, forest...

271

Analysis of mercury in simulated nuclear waste  

SciTech Connect

Mercury, Hg, is a non-radioactive component in the High Level Waste at the Savannah River Site (SRS). Thus, it is a component of the Defense Waste Processing Facility`s (DWPF) process streams. It is present because mercuric nitrate (Hg(NO{sub 3}){sub 2}) is used to dissolve spent fuel rods. Since mercury halides are extremely corrosive, especially at elevated temperatures such as those seen in a melter (1150{degrees}C), its concentration throughout the process needs to be monitored so that it is at an acceptable level prior to reaching the melter off-gas system. The Hg can be found in condensates and sludge feeds and throughout the process and process lines, i.e., at any sampling point. The different samples types that require Hg determinations in the process streams are: (1) sludges, which may be basic or acidic and may or may not include aromatic organics, (2) slurries, which are sludges with frit and will always contain organics (formate and aromatics), and (3) condensates, from feed prep and melter off-gas locations. The condensates are aqueous and the mercury may exist as a complex mixture of halides, oxides, and metal, with levels between 10 and 100 ppm. The mercury in the sludges and slurries can be Hg{sup 0}, Hg{sup +1}, or Hg{sup +2}, with levels between 200 and 3000 ppm, depending upon the location, both time and position, of sampling. For DWPF, both total and soluble Hg concentrations need to be determined. The text below describes how these determinations are being made by the Defense Waste Processing Technology (DWPT) Analytical Laboratory at the Savannah River Site. Both flame atomic absorption (FAA) and cold vapor atomic (CVAA) measurements are discussed. Also, the problems encountered in the steps toward measuring HG in these samples types of condensates and sludges are discussed along with their solutions.

Policke, T.A.; Johnson, L.C.; Best, D.R.

1991-12-31

272

Analysis of mercury in simulated nuclear waste  

SciTech Connect

Mercury, Hg, is a non-radioactive component in the High Level Waste at the Savannah River Site (SRS). Thus, it is a component of the Defense Waste Processing Facility's (DWPF) process streams. It is present because mercuric nitrate (Hg(NO{sub 3}){sub 2}) is used to dissolve spent fuel rods. Since mercury halides are extremely corrosive, especially at elevated temperatures such as those seen in a melter (1150{degrees}C), its concentration throughout the process needs to be monitored so that it is at an acceptable level prior to reaching the melter off-gas system. The Hg can be found in condensates and sludge feeds and throughout the process and process lines, i.e., at any sampling point. The different samples types that require Hg determinations in the process streams are: (1) sludges, which may be basic or acidic and may or may not include aromatic organics, (2) slurries, which are sludges with frit and will always contain organics (formate and aromatics), and (3) condensates, from feed prep and melter off-gas locations. The condensates are aqueous and the mercury may exist as a complex mixture of halides, oxides, and metal, with levels between 10 and 100 ppm. The mercury in the sludges and slurries can be Hg{sup 0}, Hg{sup +1}, or Hg{sup +2}, with levels between 200 and 3000 ppm, depending upon the location, both time and position, of sampling. For DWPF, both total and soluble Hg concentrations need to be determined. The text below describes how these determinations are being made by the Defense Waste Processing Technology (DWPT) Analytical Laboratory at the Savannah River Site. Both flame atomic absorption (FAA) and cold vapor atomic (CVAA) measurements are discussed. Also, the problems encountered in the steps toward measuring HG in these samples types of condensates and sludges are discussed along with their solutions.

Policke, T.A.; Johnson, L.C.; Best, D.R.

1991-01-01

273

Water What-ifs: Water Quality and Dissolved Oxygen  

NSDL National Science Digital Library

This Science Junction website features general information and three lesson plans about dissolved oxygen geared toward middle and high school students. Lessons cover topics such as what dissolved oxygen is, why it is important, and how decomposition of organic material affects dissolved oxygen. The third lesson includes an activity in which students are instructed to design an experiment to test effects of changes in dissolved oxygen concentration. The lessons meet several National Science Education Standards, Delaware science standards, and North Carolina competency goals.

Cleveland, April J.; Science Junction, Nc S.

274

27 CFR 19.455 - Dissolving of denaturants.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Dissolving of denaturants. 19.455 Section...Articles Denaturation § 19.455 Dissolving of denaturants. Denaturants...27 CFR part 21. Any spirits used in dissolving denaturants and contained in the...

2009-04-01

275

27 CFR 19.455 - Dissolving of denaturants.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Dissolving of denaturants. 19.455 Section...Articles Denaturation § 19.455 Dissolving of denaturants. Denaturants...27 CFR part 21. Any spirits used in dissolving denaturants and contained in the...

2010-04-01

276

Dissolved Organic Matter in the Hudson River Plume  

Microsoft Academic Search

As part of the LATTE (Lagrangian Transport and Transformation Experiment) program, dissolved organic carbon (DOC), total nitrogen (TN), and chromophoric dissolved organic matter (CDOM) were measured in the Hudson River Estuary and Plume. As revealed by high resolution measurements from the Integrated Coastal Observation System (ICOS), dissolved organic matter has several sources within the estuary including the Hudson and Raritan

R. F. Chen; G. B. Gardner

2004-01-01

277

Dissolved Nitrogen Dynamics and Dissolved Organic Carbon Biogeochemistry in an Ombrotrophic Bog  

NASA Astrophysics Data System (ADS)

As an extension of an ongoing study on carbon cycling and sequestration, Mer Bleue bog near Ottawa, Ontario was studied for dissolved nitrogen dynamics. Since nitrogen is an important nutrient for plant growth, the retention and export by the bog could reflect the impact of nitrogen deposition on bog productivity and carbon sequestration. Dissolved inorganic and organic nitrogen (DIN, DON) and dissolved organic carbon (DOC) inputs, export, and groundwater concentrations were measured over the 2003 field season (from May 21 to November 18, 2003). Nitrogen inputs were found to be entering the bog dissolved in precipitation in very small concentrations, ranging from 0 to 6 mg/L, and were dominated by NH4+. Export DON and DOC concentrations followed similar patterns, increasing with a decrease in outflow discharge with drier bog conditions throughout the season. Rough budget estimates for DOC, DON and DIN for the 2003 field season are roughly 0.034, 0.101, and 2.861 g m-2 t-1, respectively. The bog was also characterized for groundwater concentrations of DIN, DON, and DOC in the saturated and unsaturated zones of the bog. The general patterns of concentrations show dominance of NH4+ deeper in the saturated zone, and DON dominating in the unsaturated, biologically active zone. Although deposited nitrogen is dominated by inorganic forms, the internal processing of nitrogen results in DON export correlated to DOC. The results provide greater insight as to the influence and importance of dissolved nitrogen on carbon retention and sequestration.

Rattle, J. M.; Roulet, N. T.; Moore, T. R.

2004-05-01

278

Photochemical and microbial degradation of dissolved lignin phenols: Implications for the fate of terrigenous dissolved organic matter in marine environments  

Microsoft Academic Search

Molecular level characterizations of dissolved lignin were conducted in Mississippi River plume waters to study the impact of various removal mechanisms (photooxidation, microbial degradation, and flocculation) on dissolved organic material (DOM) concentrations and compositions. Prior to analysis, dissolved (1 kDalton) and low molecular weight (LMW; <1 kDalton) components. At salinities 25 psu, photooxidation was a dominant factor influencing lignin compositions

Peter J. Hernes; Ronald Benner

2003-01-01

279

Preservation of samples for dissolved mercury  

SciTech Connect

Water samples for dissolved mercury require special treatment because of the high chemical mobility and volatility of this element. Widespread use of mercury and its compounds has provided many avenues for contamination of water. Two laboratory tests were done to determine the relative permeabilities of glass and plastic sample bottles to mercury vapor. Plastic containers were confirmed to be quite permeable to airborne mercury, glass containers were virtually impermeable. Methods of preservation include the use of various combinations of acids, oxidants, and complexing agents. The combination of nitric acid and potassium dichromate successfully preserved mercury in a large variety of concentrations and dissolved forms. Because this acid-oxidant preservative acts as a sink for airborne mercury and plastic containers are permeable to mercury vapor, glass bottles are preferred for sample collection. To maintain a healthy work environment and minimize the potential for contamination of water samples, mercury and its compounds are isolated from the atmosphere while in storage. Concurrently, a program to monitor environmental levels of mercury vapor in areas of potential contamination is needed to define the extent of mercury contamination and to assess the effectiveness of mercury clean-up procedures.

Hamlin, S.N. (Geological Survey, Sacramento, CA (United States))

1989-04-01

280

Dissolved-oxygen analysis with temperature dependence  

SciTech Connect

Water-quality models to predict oxygen dynamics in streams require estimates of rates of reaeration, respiration, and primary production, which are often evaluated through diel studies. Simple, approximate methods of parameter estimation are desirable at the scoping level, and are often used for waste-load allocation studies. Scoping methods often assume that reaeration and respiration are constant over the diel period. Use of such methods, however, can yield unrealistic parameter estimates for shallow streams with a significant range of diel water temperatures, because both reaeration and respiration rates as well as the saturation concentration of dissolved oxygen are temperature-dependent. Based on this work on the Santa Margarita River in Southern California, this paper presents a modified approach to dissolved-oxygen-rate parameter estimation that takes temperature variation into account. Using a simple finite-difference approximation, temperature-normalized parameter estimates are readily optimized in a spreadsheet application. The approach is applicable to many shallow streams in which diel temperature variability is significant.

Butcher, J.B. [Cadmus Group, Durham, NC (United States); Covington, S. [Cadmus Group, Laramie, WY (United States)

1995-10-01

281

DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS  

SciTech Connect

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

NA

2004-11-22

282

Nuclear magnetic resonance parameters of atomic xenon dissolved in Gay-Berne model liquid crystal  

Microsoft Academic Search

We present constant-pressure Monte Carlo simulations of nuclear magnetic resonance (NMR) spectral parameters, nuclear magnetic shielding relative to the free atom as well as nuclear quadrupole coupling, for atomic xenon dissolved in a model thermotropic liquid crystal. The solvent is described by Gay-Berne (GB) molecules with parametrization kappa=4.4 , kappa'=20.0 , and mu=nu=1 . The reduced pressure of P*=2.0 is

Juho Lintuvuori; Michal Straka; Juha Vaara

2007-01-01

283

Respiratory Responses of Largemouth Bass (Micropterus salmoides) to Environmental Changes in Temperature and Dissolved Oxygen  

Microsoft Academic Search

Respiratory metabolic rates of largemouth bass, Micropterus salmoides, were measured in flow through respirometers under various temperature and dissolved oxygen conditions simulating drought environments. Critical oxygen tensions increased from <40 torr PO2 at 20 C, to 4050 torr at 25 C, to 5060 torr at 30 C. Evidence from arterial blood samples indicated increased anaerobic metabolism associated with an oxidative

Joseph J. Cech Jr; Clain G. Campagna; Stephen J. Mitchell

1979-01-01

284

Spawning Success of the Black Crappie, Pomoxis nigromaculatus, at Reduced Dissolved Oxygen Concentrations  

Microsoft Academic Search

Mature black crappies (Pomoxis nigromaculatus) were exposed to constant dissolved oxygen (DO) concentrations near or at 2.5, 3.5, 5.0, or 6.5 mg\\/liter, and near air saturation (control) to determine the effects of reduced DO on spawning success. The fish spawned successfully 39 times in laboratory tanks under a simulated natural temperature and light regime at all DO concentrations tested. Fish

Richard E. Siefert; Lawrence J. Herman

1977-01-01

285

Treatment of oil-in-water emulsions by coagulation and dissolved-air flotation  

Microsoft Academic Search

The treatment of oil-in-water emulsions containing n-octane (used as simulated wastewater) was investigated by means of dissolved-air flotation jar-tests. The effect of several parameters on flotation efficiency for separation of the emulsified oil was examined, namely, (a) the presence the nonionic surfactant Tween 80, used for the stabilization of the emulsions, (b) the initial pH value of the emulsions, (c)

A. I Zouboulis; A Avranas

2000-01-01

286

Benthic foraminiferal dissolved-oxygen index and dissolved-oxygen levels in the modern ocean  

Microsoft Academic Search

Changes in oxygen concentrations at the sediment-water interface play a major role in controlling benthic foraminiferal assemblages and morphologic characteristics; such changes are reflected in size, wall thickness, porosity, and also taxa (genera and species) of foraminifera present. These morphologic and taxonomic differences have been quantified as a dissolved-oxygen index. This paper demonstrates that the foraminiferal oxygen index derived from

Kunio Kaiho

1994-01-01

287

Rapid dissolving polymer compositions and uses therefor  

SciTech Connect

This patent describes a method for imparting anti-misting properties to a fuel suitable for use on turbine and diesel engines comprising: adding to the fuel a rapid dissolving particulate polymer composition in an amount sufficient to substantially eliminate that population of fuel droplets having a diameter of less than about 50 micrometers normally produced when pure fuel is subjected to wind shear, the particles of the polymer composition having a central core consisting of a high molecular weight thermoplastic polymer which imparts viscoelastic properties to a solution of the polymer in the fuel, the central core having clean surfaces and being surrounded by a multilayer shell of an adherent, particulate, coating agent selected from the group consisting of tricalcium phosphate and graphite having a particle size much smaller than that of the central core and having the interstices between the coating agent particles and around the core filled with an inert gas.

O'Mara, D.P.; Hadermann, A.F.; Trippe, J.C.

1988-12-06

288

Method for dissolving delta-phase plutonium  

DOEpatents

A process for dissolving plutonium, and in particular, delta-phase plutonium. The process includes heating a mixture of nitric acid, hydroxylammonium nitrate (HAN) and potassium fluoride to a temperature between 40.degree. and 70.degree. C., then immersing the metal in the mixture. Preferably, the nitric acid has a concentration of not more than 2M, the HAN approximately 0.66M, and the potassium fluoride 0.1M. Additionally, a small amount of sulfamic acid, such as 0.1M can be added to assure stability of the HAN in the presence of nitric acid. The oxide layer that forms on plutonium metal may be removed with a non-oxidizing acid as a pre-treatment step.

Karraker, David G. (1600 Sherwood Pl., SE., Aiken, SC 29801)

1992-01-01

289

DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS  

SciTech Connect

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with {sup 231}Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

P. Bernot

2005-07-13

290

METHOD FOR DISSOLVING LANTHANUM FLUORIDE CARRIER FOR PLUTONIUM  

DOEpatents

A method is described for dissolving lanthanum fluoride precipitates which is applicable to lanthanum fluoride carrier precipitation processes for recovery of plutonium values from aqueous solutions. The lanthanum fluoride precipitate is contacted with an aqueous acidic solution containing dissolved zirconium in the tetravalent oxidation state. The presence of the zirconium increases the lanthanum fluoride dissolved and makes any tetravalent plutonium present more readily oxidizable to the hexavalent state. (AEC)

Koshland, D.E. Jr.; Willard, J.E.

1961-08-01

291

Deformed cross-dissolves for image interpolation in scientific visualization  

Microsoft Academic Search

Deformed cross-dissolves are methods for inconspicuous interpolation between images. Wedescribe algorithms for deformation based on scattered data interpolation methods and animproved cross-dissolve algorithm offering better performance than a normal bidirectionalcross-dissolve. Results for interpolation in the field of medical visualization are presented.1 IntroductionImage interpolation has applications in scientific applications as well as in computer animation.In computer...

Detlef Ruprecht; Fb Informatik Ls

1994-01-01

292

Method for dissolving plutonium oxide with HI and separating plutonium  

DOEpatents

PuO.sub.2 -containing solids, particularly residues from incomplete HNO.sub.3 dissolution of irradiated nuclear fuels, are dissolved in aqueous HI. The resulting solution is evaporated to dryness and the solids are dissolved in HNO.sub.3 for further chemical reprocessing. Alternatively, the HI solution containing dissolved Pu values, can be contacted with a cation exchange resin causing the Pu values to load the resin. The Pu values are selectively eluted from the resin with more concentrated HI.

Vondra, Benedict L. (Oak Ridge, TN); Tallent, Othar K. (Oak Ridge, TN); Mailen, James C. (Oak Ridge, TN)

1979-01-01

293

EFFECT OF LONG-TERM REDUCTION AND DIEL FLUCTUATIONS IN DISSOLVED OXYGEN ON SPAWNING OF BLACK CRAPPIE, 'POMOXIS NIGROMACULATUS'  

EPA Science Inventory

Mature black crappies were exposed over winter in the laboratory to constant dissolved oxygen concentrations near 2.5, 4.0, 5.5, and 7.0 mg/liter. Starting on 26 April during a simulated spring-to-summer rise in water temperature, some were continued at the original oxygen concen...

294

Modeling nitrogen and phosphorus cycles and dissolved oxygen in the Pearl River (Zhujiang) Estuary* I. Model development  

Microsoft Academic Search

In the present study, an ecosystem based water quality model was designed to estimate the biochemical reaction of nutrient and dissolved oxygen in conjunction with a three-dimensional hydrodynamics and sediment model. As both phosphorus and nitrogen successively limit phytoplankton growth in many estuaries, the model simulates both these nutrient cycles using five variables each such as Human activities related to

GUAN Wei-Bing; WONG Lai-Ah; XU Dong-Feng

295

Effect of Long-term Reduction and Diel Fluctuations in Dissolved Oxygen on Spawning of Black Crappie, 'Pomoxis nigromaculatus'.  

National Technical Information Service (NTIS)

Mature black crappies were exposed over winter in the laboratory to constant dissolved oxygen concentrations near 2.5, 4.0, 5.5, and 7.0 mg/liter. Starting on 26 April during a simulated spring-to-summer rise in water temperature, some were continued at t...

A. R. Carlson L. J. Herman

1978-01-01

296

EFFECTS OF SUNLIGHT ON CARBOXYL CONTENT OF DISSOLVED ORGANIC MATTER IN THE SATILLA RIVER OF GEORGIA, UNITED STATES  

EPA Science Inventory

A study examined the effect of sunlight-initiated photo-degradation of dissolved organic matter (DOM) on its carboxyl content, and the role of oxygen and iron in this process. Solar-simulated irradiations were performed on 0.2-mm filtered water samples collected from the highly c...

297

FOREST SOIL RESPONSE TO ACID AND SALT ADDITIONS OF SULFATE III. SOLUBILIZATION AND COMPOSITION OF DISSOLVED ORGANIC CARBON  

EPA Science Inventory

A year-long experiment, using reconstructed spodosol and intact alfisol soil columns, was conducted to examine the effects of various simulated throughfall solutions on soil C dynamics. oil organic C solubilization, dissolved organic C fractions, and decomposition rates were stud...

298

Dissolved aluminium in the Southern Ocean  

NASA Astrophysics Data System (ADS)

Dissolved aluminium (Al) occurs in a wide range of concentrations in the world oceans. The concentrations of Al in the Southern Ocean are among the lowest ever observed. An all-titanium CTD sampling system makes it possible to study complete deep ocean sections of Al and other trace elements with the same high vertical resolution of 24 depths as normal for traditional CTD/Rosette sampling. Overall, 470 new data points of Al are reported for 22 full depth stations and 24 surface sampling positions along one transect. This transect consisted of 18 stations on the zero meridian proper from 5157' S until 6924'S, and 4 stations somewhat to the northeast towards Cape Town from 4220'S, 09E to 5017'S, 0127'E. The actual concentrations of Al in the Southern Ocean were lower than previously reported. The concentration of Al in the upper 25 m was relatively elevated with an average concentration of 0.71 nM ( n=22; S.D.=0.43 nM), most likely due to atmospheric input by a suggested combination of direct atmospheric (wet and dry) input and indirect atmospheric input via melting sea ice. Below the surface waters there was a distinct Al minimum with an average concentration of 0.33 nM ( n=22; S.D.=0.13 nM) at an average depth of 120 m. In the deep southernmost Weddell Basin the concentration of Al increased with depth to 0.8 nM at 4000 m, and a higher concentration of 1.5 nM in the 4500-5200 m deep Weddell Sea Bottom Water. Over the Bouvet triple junction region, where three deep ocean ridges meet, the concentration of Al increased to 1.4 nM at about 2000 m depth over the ridge crest. In the deep basin north of the Bouvet region the concentration of Al increased to higher deep values of 4-6 nM due to influence of North Atlantic Deep Water. In general the intermediate and deep distribution of Al results from the mixing of water masses with different origins, the formation of deep water and additional input from sedimentary sources at sea floor elevations. No significant correlation between Al and silicate (Si) was observed. This is in contrast to some other ocean regions. In the Southern Ocean the supply of Al is extremely low and any signal from Al uptake and dissolution with biogenic silica is undetectable against the high dissolved Si and low dissolved Al concentrations. Here the Al-Si relation in the deep ocean is uncoupled. This is due to the scavenging and subsequent loss of the water column of Al, whereas the concentration of Si increases in the deep ocean due to its input from deep dissolution of biogenic diatom frustules settling from the surface layer.

Middag, R.; van Slooten, C.; de Baar, H. J. W.; Laan, P.

2011-12-01

299

Dissolved Humic Matter in Arctic Estuaries  

NASA Astrophysics Data System (ADS)

As part of the German-Russian bilateral SIRRO(Siberian River Runoff)-project we studied the distribution of dissolved humic matter isolated by XAD-8 in the estuarine waters of the Ob and Yenisei rivers. The relative contributions of humic matter carbon to total DOC decreased from 61-77 percent in the river freshwater endmember to 35-40 percent in the marine waters of the open Kara Sea at salinities 33 psu. Humic carbon mixed conservatively in the Yenisei and non-conservatively in the Ob, where partial removal was indicated in the low salinity range. Changes in the relative contribution of humic matter to different molecular weight classes of DOM (ultrafiltration cutoffs 150 KDa, 450 KDa, 800 KDa) were studied along the salinity gradient in the Yenisei. High molecular weight DOM is relatively enriched in humics in fresh-water compared to sea-water HMW-DOM. Low molecular weight DOM is realtively enriched in humics in sea-water compared to fresh-water LMW-DOM. Throughout the estuary humic matter is depleted in 13C and nitrogen compared to total DOM, reflecting a dominant soil source. We estimate an annual input of 5 Tg humic matter carbon by the two rivers into the Kara Sea.

Spitzy, A.; Koehler, H.; Ertl, S.

2002-12-01

300

Methanex, Hoechst Celanese dissolve methanol partnership  

SciTech Connect

One of the many joint venture alliances recently announced in the petrochemical sector is ending in divorce. Hoechst Celanese Chemical (Dallas) and Methanex Corp. (Vancouver) are in the process of dissolving the partnership they had formed to restart Hoechst Celanese's methanol plant at Clear Lake, TX. Hoechst Celanese says it is actively seeking replacement partners and has several likely prospects, while Methanex is concentrating on its other ventures. Those include its just-completed acquisition of Fletcher Challenge's (Auckland, NZ) methanol business and a joint venture with American Cyanamid to convert an ammonia plant at Fortier, LA to methanol. Methanex will still be the world's largest producer of methanol. Officially, the negotiations between Methanex and Hoechst Celanese just broke down over the last month or so,' says Steve Yurich, operations manager for the Clear Lake plant. Market sources, however, say that Methanex found itself with too many irons in the fire' and pulled out before it ran into financial or perhaps even antitrust difficulties.

Morris, G.D.L.

1993-03-31

301

Microbial degradation of dissolved proteins in seawater  

SciTech Connect

An experimental protocol using radiolabeled proteins was developed to investigate the rates and mechanisms whereby dissolved proteins are degraded in natural marine plankton communities. The results of field observations and laboratory experiments indicate that proteins are degraded by a particle-bound, thermolabile system, presumably bacteria-associated enzymes, with an apparent half-saturation constant of ca. 25 ..mu..g bovine serum albumin (BSA) per liter. Gel permeation chromatography indicated that peptides of chain length intermediate between BSA and the final products of degradation (MW<700) do not accumulate in the medium. Competition experiments indicate that the system is relatively nonspecific. Turnover rates for the protein pool in samples collected in the Southern California Bight were of the same order of magnitude as the turnover rate of the L-leucine pool and were correlated with primary productivity, chlorophyll a concentrations, bacterial abundance and biomass, and L-leucine turnover rate. These data suggest that amino acids derived from proteins are utilized preferentially and do not completely mix with the amino acids in the bulk phase.

Hollibaugh, J.T.; Azam, F.

1983-11-01

302

Boiling of Water Droplets Containing Dissolved Salts  

NASA Astrophysics Data System (ADS)

We conducted experiments on the effect of dissolving three different salts (sodium chloride, sodium sulphate and magnesium sulphate) in water droplets boiling on a hot stainless steel surface. Substrate temperatures were varied from 100^oC to 300^oC. We photographed droplets as they evaporated, and recorded their evaporation time. At surface temperatures that were too low to initiate nucleate boiling, all three salts were found to reduce the evaporation rate since they lower the vapor pressure of water. In the nucleate boiling regime, sodium sulphate and magnesium sulphate enhanced heat transfer because they prevented coalescence of vapor bubbles and produced foaming in the droplet, significantly reducing droplet lifetime. The ability of salts to prevent coalescence is linked to their ionic strength: electric charge accumulated on the surfaces of bubbles produces a repulsive force, preventing them from approaching each other. Sodium chloride, which has a low ionic strength, had little effect on droplet evaporation. Low concentrations (<0.3 mol/liter) of magnesium sulphate enhanced droplet boiling by promoting foaming. However high concentrations (>0.3 mol/liter) reduce droplet evaporation rates by increasing the vapour pressure of water.

Cui, Qiang; Chandra, Sanjeev; McCahan, Susan

2000-11-01

303

Determination of dissolved aluminum in water samples  

USGS Publications Warehouse

A technique has been modified for determination of a wide range of concentrations of dissolved aluminum (Al) in water and has been tested. In this technique, aluminum is complexed with 8-hydroxyquinoline at pH 8.3 to minimize interferences, then extracted with methyl isobutyl ketone (MIBK). The extract is analyzed colorimetrically at 395 nm. This technique is used to analyze two forms of monomeric Al, nonlabile (organic complexes) and labile (free, Al, Al sulfate, fluoride and hydroxide complexes). A detection limit 2 ug/L is possible with 25-ml samples and 10-ml extracts. The detection limit can be decreased by increasing the volume of the sample and (or) decreasing the volume of the methyl isobutyl ketone extract. The analytical uncertainty of this method is approximately + or - 5 percent. The standard addition technique provides a recovery test for this technique and ensures precision in samples of low Al concentrations. The average percentage recovery of the added Al plus the amount originally present was 99 percent. Data obtained from analyses of filtered standard solutions indicated that Al is adsorbed on various types of filters. However, the relationship between Al concentrations and adsorption remains linear. A test on standard solutions also indicated that Al is not adsorbed on nitric acid-washed polyethylene and polypropylene bottle wells. (USGS)

Afifi, A. A.

1983-01-01

304

The relationship of dissolved Pb to some dissolved trace metals (Al, Cr, Mn, and Zn) and to dissolved nitrate and phosphate in a freshwater aquatic system in Mauritius  

Microsoft Academic Search

The relationship of some dissolved trace metals (Al, Cr, Mn, Zn, and Pb) with one another and to dissolved phosphate and nitrate in a freshwater aquatic system at Flic en Flac and Grand River North West (GRNW) in Mauritius (1850 km2, 20S and 57E, Western Indian ocean) is reported following trace metal determination using inductively coupled plasma mass spectrometry (ICP-MS).

R. T. Ramessur; S. J. Parry; T. Ramjeawon

2001-01-01

305

Transport of dissolved oxygen through silicone rubber membrane  

Microsoft Academic Search

The transport of dissolved oxygen in water through a silicone rubber membrane was studied theoretically and experimentally. The apparent oxygen permeability coefficients of silicone rubber were measured at various membrane thicknesses, temperatures, and concentration levels. The permeation flux was measured under both steady-and unsteady-state conditions. For the first time, the thickness effect of dissolved gas permeation has been studied. It

Sun-Tak Hwang; Thomas E. S. Tang; Karl Kammermeyer

1971-01-01

306

Tissue oxygenation with graded dissolved oxygen delivery during cardiopulmonary bypass  

Microsoft Academic Search

Background: Intravascular perfluorochemical emulsions together with a high oxygen tension may increase the delivery of dissolved oxygen to useful levels. The hypothesis of this study is that increasing the dissolved oxygen content of blood with incremental doses of a perfluorochemical emulsion improves tissue oxygenation during cardiopulmonary bypass in a dose-related fashion. Methods and Results: Oxygen utilization was studied in a

William L. Holman; Russell D. Spruell; Edward R. Ferguson; Janice J. Clymer; Walter V. A. Vicente; C. Patrick Murrah; Albert D. Pacifico

1995-01-01

307

Dissolved-Oxygen Requirements of Three Species of Fish  

Microsoft Academic Search

Critical dissolved-oxygen levels and standard metabolic rates were determined for the bluegill, Lepomis macrochirus; largemouth bass, Micropterus salmoides; and the channel catfish, Ictalurus punctatus, at 25 C., 30 C., and 35 C. Two types of experiments were conducted: shock tests in which the dissolved oxygen was dropped rapidly from near saturation to a critically low point; and acclimation tests in

D. D. Moss; D. C. Scott

1961-01-01

308

What controls dissolved iron concentrations in the world ocean?  

Microsoft Academic Search

Dissolved (< 0.4 ?m) iron has been measured in 354 samples at 30 stations in the North and South Pacific, Southern Ocean and North Atlantic by the Trace Metals Laboratory at Moss Landing Marine Laboratories. These stations are all more than 50 km from a continental margin. The global distribution of dissolved iron, which is derived from these profiles, is

Kenneth S. Johnson; R. Michael Gordon; Kenneth H. Coale

1997-01-01

309

Dissolved humic substances of the Amazon River system1  

Microsoft Academic Search

Aquatic humic and fulvic acids from nine mainstem and seven major tributary sites in the Amazon River Basin are characterized by their elemental and lignin phenol compositions. Com- bined humic substances represent 60% of the riverine dissolved organic carbon (DOC), with fulvic to humic acid (FA : HA) ratios in the mainstem averaging 4.7 -t 1 .O. All dissolved humic

John R. Ertel; John I. Hedges; Allan H. Devol; Jefrey E. Richey

1986-01-01

310

Dissolved Organic Matter Transformations: Implications for Catchment-Scale Processes  

Microsoft Academic Search

Particulate and dissolved phase lignin parameters are used to understand sources and dynamics of terrigenous organic matter (OM) in freshwater and marine systems. Impacts of catchment properties, such as soil type and mineralogy, vegetation distribution and hydrologic conditions on terrestrial dissolved and particulate biomarker compositions have not been addressed. Our experimental approach deciphers relative contributions of these parameters on bulk

A. Robinson; P. Hernes; I. Montanez; B. Eustis

2006-01-01

311

Groundwater flow and dissolved carbon movement in a boreal peatland  

Microsoft Academic Search

Measurement of the groundwater flux and the consequent advection of dissolved carbon (DOC (dissolved organic carbon), CH4 and CO2) were made in a boreal peatland in northern Sweden in summer 1993. The early summer gradients in hydraulic head indicated a downward flux of water in the peatland, but after a persistent mid-summer dry period the gradients changed to produce an

J. M. Waddington; N. T. Roulet

1997-01-01

312

A bulk silicon dissolved wafer process for microelectromechanical devices  

Microsoft Academic Search

A single-sided bulk silicon dissolved wafer process that has been used to fabricate several different micromechanical structures is described. It involves the simultaneous processing of a glass wafer and a silicon wafer, which are eventually bonded together electrostatically. The silicon wafer is then dissolved to leave heavily boron doped devices attached to the glass substrate. Overhanging features can be fabricated

Yogesh B. Gianchandani; Khalil Najafi

1992-01-01

313

Dissolved P in streams in dry years and wet years  

Technology Transfer Automated Retrieval System (TEKTRAN)

Dissolved phosphorus (P) has often been identified as the nutrient of concern in lakes, reservoirs, and streams especially where there is evidence of eutrophication. We analyzed contiguous-spatial and temporal variability of dissolved P [soluble reactive P (SRP)] stream concentrations during times ...

314

Kinetics of enhanced gold dissolution: activation by dissolved silver  

Microsoft Academic Search

Coupled oxygen reduction and metal oxidation occur during leaching of gold in cyanide solutions. Both processes are altered by specific surface-active constituents in solution. Dissolved cyanide in solution depresses the rate of oxygen reduction while the presence of silver in solution enhances the rate of reduction. Similarly, the oxidation (dissolution) rate of gold is dramatically increased by dissolved silver in

Milton E. Wadsworth; Ximeng Zhu

2003-01-01

315

Evaluation of filter media for clarification of partially dissolved residues containing plutonium  

SciTech Connect

A common process in the chemical industry employs the leaching of a desirable component from an insoluble substrate, followed by filtration to produce a clarified solution of the desirable component and a discardable residue. The work described here involved evaluating sintered metal filter media for separating dissolved plutonium from undissolved residues generated at various locations owned by the Department of Energy throughout the United States. The work was performed during a six-week assignment at the Savannah River Laboratory as part of a high school science enrichment program conducted in the summer of 1989. The leach step used included dissolving the plutonium-containing solids in a solution of nitric-hydrofluoric acid. To simulate the partial solubility of the actual plutonium-containing residues, a non-radioactive power plant flyash was used. 6 refs., 14 figs., 1 tab.

Foley, E.S.

1989-10-09

316

Distributed hydrological modeling of total dissolved phosphorus transport in an agricultural landscape, part II: dissolved phosphorus transport  

NASA Astrophysics Data System (ADS)

Reducing non-point source phosphorus (P) loss to drinking water reservoirs is a main concern for New York City watershed planners. A spatially distributed model of total dissolved phosphorus (TDP) loading was developed using raster maps covering a watershed with 164-ha dairy farm. Transport of TDP was calculated separately for baseflow and for surface runoff from manure-covered and non-manure-covered areas. Soil test P, simulated rainfall application, and land use were used to predict concentrations of TDP in overland flow from non-manure covered areas. Concentrations in runoff for manure-covered areas were computed from predicted cumulative flow and elapsed time since manure application, using field-specific manure spreading data. Baseflow TDP was calibrated from observed concentrations using a temperature-dependent coefficient. An additional component estimated loading associated with manure deposition on impervious areas, such as barnyards and roadways. Daily baseflow and runoff volumes were predicted for each 10-m cell using the Soil Moisture Distribution and Routing Model (SMDR). For each cell, daily TDP loads were calculated as the product of predicted runoff and estimated TDP concentrations. Predicted loads agreed well with loads observed at the watershed outlet when hydrology was modeled accurately (R2 79% winter, 87% summer). Lack of fit in early spring was attributed to difficulty in predicting snowmelt. Overall, runoff from non-manured areas appeared to be the dominant TDP loading source factor.

Hively, W. D.; Grard-Marchant, P.; Steenhuis, T. S.

2005-08-01

317

Distributed hydrological modeling of total dissolved phosphorus transport in an agricultural landscape, part II: dissolved phosphorus transport  

NASA Astrophysics Data System (ADS)

Reducing non-point source phosphorus (P) loss to drinking water reservoirs is a main concern for New York City watershed planners, and modeling of P transport can assist in the evaluation of agricultural effects on nutrient dynamics. A spatially distributed model of total dissolved phosphorus (TDP) loading was developed using raster maps covering a 164-ha dairy farm watershed. Transport of TDP was calculated separately for baseflow and for surface runoff from manure-covered and non-manure-covered areas. Soil test P, simulated rainfall application, and land use were used to predict concentrations of TDP in overland flow from non-manure covered areas. Concentrations in runoff for manure-covered areas were computed from predicted cumulative flow and elapsed time since manure application, using field-specific manure spreading data. Baseflow TDP was calibrated from observed concentrations using a temperature-dependent coefficient. An additional component estimated loading associated with manure deposition on impervious areas, such as barnyards and roadways. Daily baseflow and runoff volumes were predicted for each 10-m cell using the Soil Moisture Distribution and Routing Model (SMDR). For each cell, daily TDP loads were calculated as the product of predicted runoff and estimated TDP concentrations. Predicted loads agreed well with loads observed at the watershed outlet when hydrology was modeled accurately (R2 79% winter, 87% summer). Lack of fit in early spring was attributed to difficulty in predicting snowmelt. Overall, runoff from non-manured areas appeared to be the dominant TDP loading source factor.

Hively, W. D.; Grard-Marchant, P.; Steenhuis, T. S.

2006-04-01

318

Safe thickness for D1 dissolver with 1500 GM plutonium  

SciTech Connect

There is some concern that the FB-Line D1 dissolver may have been pressurized above the liquid head pressure by a reaction that occurred in the dissolver. The D1 Pu limit of 8.8 kg is based on a tank with an inner slab thickness of 3.34 inches and a wall thickness of 0.40 inches for a total slab thickness of 4.14 inches. When the incident occurred there was less than 1,500 gm Pu (1,323 gm) in the dissolver. Some calculations were made to determine the safe slab thickness for 1,500 gm Pu in the D1 dissolver. Calculations show that 1,500 gm Pu can be safely contained in a 6 inch thick D1 dissolver provided the cabinet panels are in place.

Reilly, T.A.

1988-01-20

319

Treatment of trichloroethene and hexavalent chromium by granular iron in the presence of dissolved CaCO3  

NASA Astrophysics Data System (ADS)

Column experiments and numerical simulations were conducted to evaluate the effects of Cr(VI) and dissolved CaCO3 on the iron reactivity towards trichloroethene (TCE) and Cr(VI) reduction. Column experiments included measurements of iron corrosion potential and characterization of surface film composition using Raman spectroscopy. Three columns received different combinations of TCE (5 mg L- 1), Cr(VI) (10 mg L- 1) and dissolved CaCO3 (300 mg L- 1), after short periods of conditioning with Millipore water followed by 10 mg L- 1 TCE in Millipore water, for a total of 8 months. The results showed that co-existence with TCE did not affect Cr(VI) reduction kinetics, however, the presence of Cr(VI) reduced TCE degradation rates significantly. The formation of Fe(III)/Cr(III) products caused progressive passivation of the iron and was consistent with the increase in corrosion potential. The presence of dissolved CaCO3 resulted in a stable corrosion potential and faster degradation rates of TCE and Cr(VI). Over time, however, the accumulation of secondary carbonate minerals on the iron surface decreased the iron reactivity. Numerical simulation using a reactive transport model reproduced the observations from the column experiments reasonably well. The simulation can be valuable in the design of PRBs or in the development of effective maintenance procedures for PRBs treating groundwater co-contaminated with Cr(VI) and TCE in the presence of dissolved CaCO3.

Jeen, Sung-Wook; Yang, YanQi; Gui, Lai; Gillham, Robert W.

2013-01-01

320

Dissolved organic carbon fluxes under bare soil.  

PubMed

The flux of dissolved organic carbon (DOC) in soil facilitates transport of nutrients and contaminants in soil. There is little information on DOC fluxes and the relationship between DOC concentration and water flux in agricultural soils. The DOC fluxes and concentrations were measured during 2.5 yr using 30 automatic equilibrium tension plate lysimeters (AETPLs) at 0.4 m and 30 AETPLs at 1.20-m depth in a bare luvisol, previously used as an arable soil. Average annual DOC fluxes of the 30 AETPLS were 4.9 g C m(-2) y(-1) at 0.4 m and 2.4 g C m(-2) y(-1) at 1.2 m depth. The average leachate DOC concentrations were 17 mg C L(-1) (0.4 m) and 9 mg C L(-1) (1.2 m). The DOC concentrations were unrelated to soil moisture content or average temperature and rarely dropped below 9 mg C L(-1) (0.4 m) and 5 mg C L(-1) (1.2 m). The variability in cumulative DOC fluxes among the plates was positively related to leachate volume and not to average DOC concentrations at both depths. This suggests that water fluxes are the main determinants of spatial variability in DOC fluxes. However, the largest DOC concentrations were inversely proportional to the mean water velocity between succeeding sampling periods, suggesting that the maximal net DOC mobilization rate in the topsoil is limited. Elevated DOC concentrations, up to 90 mg C L(-1), were only observed at low water velocities, reducing the risks of DOC-facilitated transport of contaminants to groundwater. The study emphasizes that water flux and velocity are important parameters for DOC fluxes and concentrations. PMID:17332264

Mertens, Jan; Vanderborght, Jan; Kasteel, Roy; Ptz, Thomas; Merckx, Roel; Feyen, Jan; Smolders, Erik

2007-03-01

321

Chemical characterization of dissolvable tobacco products promoted to reduce harm.  

PubMed

In 2009, the R. J. Reynolds Tobacco Co. released a line of dissolvable tobacco products that are marketed as an alternative to smoking in places where smoking is prohibited. These products are currently available in Indianapolis, IN, Columbus, OH, and Portland, OR. This paper describes the chemical characterization of four such products by gas chromatography-mass spectrometry (GC-MS). The dissolvable tobacco products were extracted and prepared by ultrasonic extraction using acetone, trimethylsilyl derivatization, and headspace solid phase microextraction (SPME). The following compounds were identified in the dissolvables using either ultrasonic extractions or trimethylsilyl derivatization: nicotine, ethyl citrate, palmitic acid, stearic acid, sorbitol, glycerol, and xylitol. The following compounds were identified in the dissolvables using headspace SPME: nicotine, ethyl citrate, cinnamaldehyde, coumarin, vanillin, and carvone. With the exception of nicotine, the compounds identified thus far in the dissolvables are either flavoring compounds or binders. The concentration of free nicotine in the dissolvables was determined from the Henderson-Hasselbalch equation and by measuring the pH and nicotine concentration by GC-MS. The results presented here are the first to reveal the complexity of dissolvable tobacco products and may be used to assess potential oral health effects. PMID:21332188

Rainey, Christina L; Conder, Paige A; Goodpaster, John V

2011-02-18

322

Dissolved oxygen as an indicator of bioavailable dissolved organic carbon in groundwater  

USGS Publications Warehouse

Concentrations of dissolved oxygen (DO) plotted vs. dissolved organic carbon (DOC) in groundwater samples taken from a coastal plain aquifer of South Carolina (SC) showed a statistically significant hyperbolic relationship. In contrast, DO-DOC plots of groundwater samples taken from the eastern San Joaquin Valley of California (CA) showed a random scatter. It was hypothesized that differences in the bioavailability of naturally occurring DOC might contribute to these observations. This hypothesis was examined by comparing nine different biochemical indicators of DOC bioavailability in groundwater sampled from these two systems. Concentrations of DOC, total hydrolysable neutral sugars (THNS), total hydrolysable amino acids (THAA), mole% glycine of THAA, initial bacterial cell counts, bacterial growth rates, and carbon dioxide production/consumption were greater in SC samples relative to CA samples. In contrast, the mole% glucose of THNS and the aromaticity (SUVA254) of DOC was greater in CA samples. Each of these indicator parameters were observed to change with depth in the SC system in a manner consistent with active biodegradation. These results are uniformly consistent with the hypothesis that the bioavailability of DOC is greater in SC relative to CA groundwater samples. This, in turn, suggests that the presence/absence of a hyperbolic DO-DOC relationship may be a qualitative indicator of relative DOC bioavailability in groundwater systems.

Chapelle, Francis H.; Bradley, Paul M.; McMahon, Peter B.; Kaiser, Karl; Benner, Ron

2012-01-01

323

Chemical and optical phototransformation of dissolved organic matter.  

PubMed

Dissolved organic matter represents the main reservoir of organic carbon in most aquatic ecosystems. In the present study, we determined the optical changes and the quantum yields of transient species formation for chromophoric dissolved organic matter (CDOM) samples undergoing photodegradation. The results show that the triplet states (3)CDOM* are potentially key players in CDOM photodegradation and that such transformations are strongly influenced by small differences in CDOM sources and sinks. In contrast, OH radicals are very unlikely to play a key role in phototransformation. These results represent an important first step in combining optical and transient species analyses to understand photodegradation processes of dissolved organic matter. PMID:22503589

Loiselle, Steven; Vione, Davide; Minero, Claudio; Maurino, Valter; Tognazzi, Antonio; Dattilo, Arduino M; Rossi, Claudio; Bracchini, Luca

2012-03-23

324

Dissolved gas and isotopic tracers of denitrification  

SciTech Connect

We present results from field studies in California (USA) where tritium-helium age dating is used in conjunction with major gases (N{sub 2}, O{sub 2}, CH{sub 4}, CO{sub 2}), noble gases (He, Ne, Ar, Kr, Xe), and stable isotopes ({sup 15}N/{sup 14}N, {sup 18}O/{sup 16}O) in order to document nitrate loading and denitrification associated with confined animal agricultural operations and septic systems. Preliminary results show that in-field extraction of the full suite of dissolved gases will be possible using a new Gas Extraction System under development to augment the current Noble Gas Mass Spectrometry and Membrane Inlet Mass Spectrometry techniques. Ascribing observed groundwater nitrate levels to specific current and past land use practices is often complicated by uncertainty in groundwater age and the degree and locus of dentrification. Groundwater age dating at dairy field sites using the {sup 3}H-{sup 3}He method indicates that the highest nitrate concentrations (150-260 mg/L-NO3) occur in waters with apparent ages of <5 yrs, whereas older waters contain excess N{sub 2} from saturated zone denitrification [1]. At a residential septic system site in Livermore, CA, waters with young apparent ages (<1 yr) proximal to leach line drainage have lower nitrate concentrations and elevated nitrate {delta}{sup 15}N and {delta}{sup 18}O values consistent with denitrification, but little evidence for excess N{sub 2}, indicating that denitrification is occurring in the unsaturated zone. Degassing of groundwater can complicate efforts to calculate travel times [2] and to quantify denitrification. Degassed groundwater underlying dairy operations is formed by two distinct mechanisms: (1) recharge of manure lagoon water affected by biogenic gas ebullition [3] and (2) saturated zone denitrification producing N{sub 2} gas above solubility in groundwater. Gas loss due to both mechanisms is evident in the concentrations of noble gases and major gases in dairy groundwater samples.

Singleton, M J; Moran, J E; Esser, B K; McNab, W W; Carle, S F; Cey, B D

2008-02-28

325

Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate-Scale Hydrodynamic Model  

SciTech Connect

The Washington State Department of Ecology contracted with Pacific Northwest National Laboratory to develop an intermediate-scale hydrodynamic and water quality model to study dissolved oxygen and nutrient dynamics in Puget Sound and to help define potential Puget Sound-wide nutrient management strategies and decisions. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or dominate human impacts to dissolved oxygen levels in the sensitive areas. In this study, an intermediate-scale hydrodynamic model of Puget Sound was developed to simulate the hydrodynamics of Puget Sound and the Northwest Straits for the year 2006. The model was constructed using the unstructured Finite Volume Coastal Ocean Model. The overall model grid resolution within Puget Sound in its present configuration is about 880 m. The model was driven by tides, river inflows, and meteorological forcing (wind and net heat flux) and simulated tidal circulations, temperature, and salinity distributions in Puget Sound. The model was validated against observed data of water surface elevation, velocity, temperature, and salinity at various stations within the study domain. Model validation indicated that the model simulates tidal elevations and currents in Puget Sound well and reproduces the general patterns of the temperature and salinity distributions.

Yang, Zhaoqing; Khangaonkar, Tarang; Labiosa, Rochelle G.; Kim, Taeyun

2010-11-30

326

Photoformation of low-molecular-weight organic acids from brown water dissolved organic matter.  

PubMed

This work describes the effects of simulated solar UV light on the bulk properties of dissolved organic matter (DOM) of bog lake water and on the formation of low-molecular-weight organic acids (LMWOAs). By means of size-exclusion chromatography it was shown that the more hydrophilic moieties of the DOM were preferentially photodegraded while the more hydrophobic ones remained relatively unaffected or were even formed. The combined photochemical-biological degradation proved to be more important than the pure photochemical mineralization. Formic, acetic, pyruvic, oxalic, malonic, and succinic acids were identified as important degradation products. Their contribution to the dissolved organic carbon increased from 0.31% before to 6.4% after 24 h irradiation. About 33% of the bioavailable photoproducts of DOM were comprised of these LMWOAs. The influence of nitrate on the formation of carboxylic acids could not be observed in the investigated system. Kinetic experiments indicated that degradation of LMWOAs occurred simultaneously during irradiation experiments, alpha-oxygen-substituted LMWOAs being more amenable to these processes. Dissolved iron acted as a catalyst of DOM photodegradation and LMWOA photoformation. Copper played an antagonistic role in the irradiation experiments, reducing the formation of formic, acetic, and malonic acids while increasing the formation of oxalic acid. PMID:14524452

Brinkmann, Thomas; Hrsch, Philip; Sartorius, Daniel; Frimmel, Fritz H

2003-09-15

327

High-pressure injection of dissolved oxygen for hydrocarbon remediation in a fractured dolostone aquifer.  

PubMed

A field experiment was completed at a fractured dolomite aquifer in southwestern Ontario, Canada, to assess the delivery of supersaturated dissolved oxygen (supersaturated with respect to ambient conditions) for enhanced bioremediation of petroleum hydrocarbons in groundwater. The injection lasted for 1.5h using iTi's gPro oxygen injection technology at pressures of up to 450 kPa and at concentrations of up to 34 mg O?/L. A three-dimensional numerical model for advective-dispersive transport of dissolved oxygen within a discretely-fractured porous medium was calibrated to the observed field conditions under a conservative (no-consumption) scenario. The simulation demonstrated that oxygen rapidly filled the local intersecting fractures as well as the porous matrix surrounding the injection well. Following injection, the local fractures were rapidly flushed by the natural groundwater flow system but slow back-diffusion ensured a relatively longer residence time in the matrix. A sensitivity analysis showed significant changes in behaviour with varying fracture apertures and hydraulic gradients. Applying the calibrated model to a 7-day continuous injection scenario showed oxygen residence times (at the 3mg/L limit), within a radius of 2-4m from the injection well, of up to 100 days. This study has demonstrated that supersaturated dissolved oxygen can be effectively delivered to this type of a fractured and porous bedrock system at concentrations and residence times potentially sufficient for enhanced aerobic biodegradation. PMID:20727615

Greer, K D; Molson, J W; Barker, J F; Thomson, N R; Donaldson, C R

2010-07-27

328

On the DMSO-dissolved state of insulin: a vibrational spectroscopic study of structural disorder.  

PubMed

Upon dissolving in dimethyl sulfoxide (DMSO), native insulin and insulin amyloid fibrils convert into an identical disordered structural state based on IR spectral characteristics. Here, we investigate the DMSO-denatured state of insulin using a number of spectroscopic methods: near-UV circular dichroism, infrared absorption spectroscopy, vibrational circular dichroism (VCD), Raman scattering, and Raman optical activity (ROA), as well as by carrying out 140-ns-long molecular dynamics (MD) simulations of DMSO-dissolved native insulin monomers. According to this work, the DMSO-solvated state of insulin is an ensemble of conformations including polyproline II-type helix and possibly a residual ?-helical structure. Effects of DMSO-specific solvation and conformation-restricting covalent structure of insulin (including the three intact disulfide bridges) are argued to play important roles in stabilizing the disordered state of the protein. A comparison of ROA spectra of insulin dissolved in fully deuterated and nondeuterated DMSO suggested transfer of chirality from the protein to the otherwise ROA-silent solvent. Our study provides an example of a biological protein that acquires a substantial population of PP II conformation in an entirely nonaqueous environment. The DMSO-unfolded state of insulin and its dynamics are also discussed in the context of the established link between PP II conformation and protein misfolding. PMID:22963549

Dzwolak, Wojciech; Kalinowski, Jaros?aw; Johannessen, Christian; Babenko, Viktoria; Zhang, Ge; Keiderling, Timothy A

2012-09-19

329

Utilization of Dissolved Organic Carbon by Heterotrophic Bacteria and Protozoa.  

National Technical Information Service (NTIS)

The research has investigated in batch and continuous culture laboratory microcosms the relationships between level and turnover rate of dissolved organic carbon substrates and the interactions among microbial populations at three trophic levels in a hete...

J. M. Graham R. P. Canale S. L. Allen

1979-01-01

330

DISSOLVED AIR FLOTATION TREATMENT OF GULF SHRIMP CANNERY WASTEWATER  

EPA Science Inventory

This study reports on the operation of a plant scale dissolved air flotation system installed to define and evaluate attainable shrimp cannery wastewater treatment levels. The system was operated in all three modes of DAF pressurization. Destabilizing coagulants investigation inc...

331

Dissolving Solids, Liquids, and Gases | Inquiry in Action  

NSDL National Science Digital Library

In this series of six investigations, students will participate in activities that help them better understand the different factors that affect the solubility of solids, liquids, and gases. First, students will add sugar and food coloring to different liquids to discover that substances dont necessarily dissolve in all liquids. Students will then add cocoa mix to hot and cold water, and see that this solute dissolves better in hot water. However, the following teacher demonstration shows that increasing the temperature of water has very little effect on the solubility of salt. Students also experiment with the effect of temperature on carbon dioxide gas dissolved in water. Students should conclude that temperature affects the solubility of substances in different ways. As a culminating challenge, students use their knowledge of dissolving solids, liquids, and gases in water to create a fizzy lemon soda.

Society, American C.

2010-07-02

332

Prediction of Total Dissolved Gas Exchange at Hydropower Dams, Report.  

National Technical Information Service (NTIS)

Total dissolved gas (TDG) supersaturation in waters released at hydropower dams can cause gas bubble trauma in fisheries resulting in physical injuries and eyeball protrusion that can lead to mortality. Elevated TDG pressures in hydropower releases are ge...

B. Hadjerioua F. K. Pasha K. Stewart M. D. Bender M. L. Schneider

2013-01-01

333

High-Performance Aerating Weirs for Dissolved Oxygen Improvement.  

National Technical Information Service (NTIS)

New concepts in aerating weir design are being explored for improving dissolved oxygen in tailwaters downstream from hydropower projects with oxygen deficient releases. Reliable design procedures are being deVeloped from experiences of the Tennessee Valle...

D. I. Morris G. E. Hauser

2009-01-01

334

Companies that are marketing, or test marketing, dissolvable ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Companies that are marketing, or test marketing, dissolvable tobacco products were invited to present at the July 21-22, 2011 TPSAC meeting. ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

335

INVESTIGATION OF A HONEYWELL DISSOLVED OXYGEN PARAMETRIC SYSTEM  

EPA Science Inventory

A Honeywell dissolved oxygen parametric system was investigated for possible application in EPA's research on sewage treatment. Laboratory and field data were accumulated. Summaries on selected background and theoretical aspects of the measurement have been included for those unf...

336

Simplified Method for Dissolved DNA Determination in Aquatic Environments  

PubMed Central

A method was developed for the determination of dissolved DNA in aquatic environments. The method is based upon the concentration of dissolved DNA by ethanol precipitation of 0.2-?m-pore-size filtered water. The DNA in concentrated extracts was quantified by the fluorescence of Hoechst 33258-DNA complexes. Fluorescence not attributable to DNA was corrected for by DNase I digestion of the extracts and averaged 25% of the total fluorescence for all samples. The effectiveness of the procedure for concentrating dissolved DNA was demonstrated by the efficient (>90%) recovery of internal standards. Concentrations of dissolved DNA from a variety of marine and freshwater environments ranged from 0.2 to 44 ?g/liter, with the highest values being obtained for estuarine and river environments. The method is simple, specific for DNA, and more sensitive than previously described methods for the determination of extracellular DNA.

DeFlaun, Mary F.; Paul, John H.; Davis, Dean

1986-01-01

337

DESIGN PROCEDURES FOR DISSOLVED OXYGEN CONTROL OF ACTIVATED SLUDGE PROCESSES  

EPA Science Inventory

This report presents design procedures and guidelines for the selection of aeration equipment and dissolved (DO) control systems for activated sludge treatment plants. Aeration methods, equipment and application techniques are examined and selection procedures offered. Various DO...

338

The exchange rate between dissolved tripalmitin and tripalmitin crystals.  

PubMed

The focus of this paper is on understanding the exchange between dissolved fats and fat crystals in dispersions by quantifying the rate of the exchange between the fats in solution and in crystals. In the studies reported here, tripalmitin (PPP) was used as model fat. The dispersions contained PPP crystals and dissolved radio-labelled PPP (14C-PPP, used as the probe) in a medium chain triglyceride oil (MCT). The exchange process between the dissolved 14C-PPP and unlabelled PPP crystals was followed using a radio-detector. The effect of the crystal concentration on the exchange rate was studied. The results suggested that the rate of the exchange is dependent upon both the dissolution of the surface of the crystals and also diffusion and crystallisation of the dissolved compounds. PMID:11377952

Haghshenas, N; Smith, P; Bergensthl, B

2001-07-01

339

Dissolved gas analysis of alternative fluids for power transformers  

Microsoft Academic Search

Ester-based transformer fluids have the same DGA fingerprints as mineral oil. However, with lower volumes of gas produced, they will demand more precise dissolved gas measurements and modified or new ratio criteria to allow fault detection and diagnosis.

Imad-U-Khan; Zhongdong Wang; I. Cotton; S. Northcote

2007-01-01

340

DOES DISSOLVED INORGANIC CARBON PLAY A ROLE IN ARSENIC MOBILIZATION?  

EPA Science Inventory

Recent experimental results provide evidence that dissolved inorganic carbon plays a direct role in mobilizing arsenic in anoxic aquatic environments. This hypothesis is partially supported by observed correlations between elevated levels of arsenic and alkalinity in a ground wa...

341

Suspended and Dissolved Solids Effects on Freshwater Biota: A Review.  

National Technical Information Service (NTIS)

It is widely recognized that suspended and dissolved solids in lakes, rivers, streams, and reservoirs affect water quality. In this report the research needs appropriate to setting freshwater quality criteria or standards for suspended solids (not includi...

D. L. Sorenson M. M. McCarthy E. J. Middlebrooks D. B. Porcella

1977-01-01

342

Low-Nitrosamine Dissolvable Tobacco Products Star Scientific ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Low-Nitrosamine Dissolvable Tobacco Products Star Scientific, Inc. Part II ... 26 The Major Issue The most concerning risk for Star with the ARIVA and ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

343

EFFECTS OF TEMPERATURE VARIATION ON CRITICAL STREAM DISSOLVED OXYGEN  

EPA Science Inventory

The classical assumption that the lowest dissolved oxygen (DO) occurs at the highest temperature may not always hold. The DO saturation concentration decreases monotonically with increasing temperature, lowering the DO, but the reaeration coefficient increases monotonically with ...

344

FIELD MEASUREMENT OF DISSOLVED OXYGEN: A COMPARISON OF TECHNIQUES  

EPA Science Inventory

The measurement and interpretation of geochemical redox parameters are key components of ground water remedial investigations. Dissolved oxygen (DO) is perhaps the most robust geochemical parameter in redox characterization; however, recent work has indicated a need for proper da...

345

Considerations with regard to TPSAC's review of dissolvable ...  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. Considerations with regard to TPSAC's review of dissolvable tobacco products Jonathan M. Samet (Draft: October 31, 2011) Overview ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

346

Littoral-Pelagial Interactions: The Role of Dissolved Humic Materials.  

National Technical Information Service (NTIS)

Relationships between ultraviolet absorbance, fluorescence, and concentrations of dissolved organic carbon (DOC) were examined in four model humic materials. Fluorescence was consistently a poor predictor of DOC concentration, and absorbance correctly pre...

A. J. Stewart

1980-01-01

347

Low-Nitrosamine Dissolvable Tobacco Products Star Scientific ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... at every level of the population Low-Nitrosamine Dissolvable Tobacco Products Star Scientific, Inc. Part III ... 18 Page 19. 19 Star's Recommendations ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

348

40 CFR 430.10 - Applicability; description of the dissolving kraft subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the dissolving kraft subcategory. 430.10...PAPERBOARD POINT SOURCE CATEGORY Dissolving Kraft Subcategory § 430.10 Applicability; description of the dissolving kraft subcategory. The...

2009-01-01

349

40 CFR 430.40 - Applicability; description of the dissolving sulfite subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the dissolving sulfite subcategory. 430.40...PAPERBOARD POINT SOURCE CATEGORY Dissolving Sulfite Subcategory § 430.40 Applicability; description of the dissolving sulfite subcategory. The...

2010-07-01

350

40 CFR 430.40 - Applicability; description of the dissolving sulfite subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the dissolving sulfite subcategory. 430.40...PAPERBOARD POINT SOURCE CATEGORY Dissolving Sulfite Subcategory § 430.40 Applicability; description of the dissolving sulfite subcategory. The...

2009-01-01

351

40 CFR 430.10 - Applicability; description of the dissolving kraft subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the dissolving kraft subcategory. 430.10...PAPERBOARD POINT SOURCE CATEGORY Dissolving Kraft Subcategory § 430.10 Applicability; description of the dissolving kraft subcategory. The...

2010-07-01

352

Clarification of dissolved irradiated light-water-reactor fuel  

Microsoft Academic Search

Bench-scale studies with actual dissolved irradiated light water reactor (LWR) fuels showed that continuous centrifugation is a practical clarification method for reprocessing. Dissolved irradiated LWR fuel was satisfactorily clarified in a bench-scale, continuous-flow bowl centrifuge. The solids separated were successfully reslurried in water. When the reslurried solids were mixed with clarified centrate, the resulting suspension behaved similar to the original

1983-01-01

353

Oxygen isotope fractionation in dissolved oxygen in the deep sea  

Microsoft Academic Search

18O variations in dissolved oxygen have been measured at five stations from the eastern equatorial Pacific, at the GEOSECS-I and -II intercalibration stations in the North Pacific and North Atlantic, and along an Antarctic-South Pacific section from MONSOON expedition. Relative to atmospheric oxygen, dissolved oxygen in the ocean is enriched in 18O up to a maximum of 140\\/00, the extreme

P. Kroopnick; H. Craig

1976-01-01

354

The Dissolution of Desicooler Residues in H-Canyon Dissolvers  

SciTech Connect

A series of dissolution and characterization studies has been performed to determine if FB-Line residues stored in desicooler containers will dissolve using a modified H-Canyon processing flowsheet. Samples of desicooler materials were used to evaluate dissolving characteristics in the low-molar nitric acid solutions used in H-Canyon dissolvers. The selection for the H-Canyon dissolution of desicooler residues was based on their high-enriched uranium content and trace levels of plutonium. Test results showed that almost all of the enriched uranium will dissolve from the desicooler materials after extended boiling in one molar nitric acid solutions. The residue that contained uranium after completion of the extended boiling cycle consisted of brown solids that had agglomerated into large pieces and were floating on top of the dissolver solution. Addition of tenth molar fluoride to a three molar nitric acid solution containing boron did not dissolve remaining uranium from the brown solids. Only after boiling in an eight molar nitric acid-tenth molar fluoride solution without boron did remaining uranium and aluminum dissolve from the brown solids. The amount of uranium associated with brown solids would be approximately 1.4 percent of the total uranium content of the desicooler materials. The brown solids that remain in the First Uranium Cycle feed will accumulate at the organic/aqueous interface during solvent extraction operations. Most of the undissolved white residue that remained after extended boiling was aluminum oxide containing additional trace quantities of impurities. However, the presence of mercury used in H-Canyon dissolvers should complete the dissolution of these aluminum compounds.

Gray, J.H.

2003-06-23

355

Photodegradation of fluorescent dissolved organic matter in river waters  

Microsoft Academic Search

Photodegradation of dissolved organic matter (DOM), collected from two upstream and one downstream sites in the Lake Biwa watershed in Japan, was investigated using fluorescence properties of three-dimensional excitation emission matrix (3-D EEM). Solar irradiation caused a decrease in the dissolved organic carbon (DOC) concentration and in the fluorescence peak intensity (FI) of fulvic acid (FA)- and protein-like substances in

KHAN M. G. MOSTOFA; TAKAHITO YOSHIOKA; EIICHI KONOHIRA; EIICHIRO TANOUE

356

Dissolved Vanillin as Tracer for Estuarine Lignin Conversion  

NASA Astrophysics Data System (ADS)

Lignin is produced only by vascular plants and therefore can be used as a tracer for terrestrial organic carbon input to the estuarine and marine environments. Lignin measurements have been done by analyses of the oxidation products such as vanillin or 4-hydroxybenzaldehyde. In the Elbe Estuary, free dissolved vanillin was analysed in order to test whether such measurements yield information on terrestrial carbon inputs into the Estuary and on the vanillin derived from lignin oxidation. In the period 1990-1992, concentrations of dissolved vanillin in the Elbe ranged from 0 to 60 ? g l -1(mean: 8 ?g l -1). Higher values were found in areas of increased microbial activity such as the turbidity zone and the river mouth where the water chemistry is influenced by large tidal flats. No correlation was found between dissolved vanillin and suspended matter concentrations, although lignin is normally associated with suspended particulate matter, nor was a covariance seen between dissolved vanillin and the terrestrial carbon inputs into the Estuary. Apparently, biological conversion of lignin was faster than the transport processes, and local sources were more dominant for the vanillin concentration than riverine sources. The dissolved vanillin turnover was fast and, consequently, a significant amount of lignin may be converted within an estuary. In sediments from the Estuary, the concentrations of dissolved vanillin were similar to those found in the water phase and showed no clear vertical profile. The sediment is unlikely to be the source for vanillin.

Edelkraut, F.

1996-12-01

357

Dissolved Organic Matter in the Hudson River Plume  

NASA Astrophysics Data System (ADS)

As part of the LATTE (Lagrangian Transport and Transformation Experiment) program, dissolved organic carbon (DOC), total nitrogen (TN), and chromophoric dissolved organic matter (CDOM) were measured in the Hudson River Estuary and Plume. As revealed by high resolution measurements from the Integrated Coastal Observation System (ICOS), dissolved organic matter has several sources within the estuary including the Hudson and Raritan Rivers, and a yet unidentified anthropogenic source off Manhattan. The quantity of dissolved organic matter that is exported from the Hudson River Estuary is significantly greater than that which the Hudson River can supply by simply conservative mixing with coastal seawater. In May, 2004, rhodamine dye was injected at the surface as the plume flowed out onto the New York/New Jersey shelf, once as the plume turned north towards Long Island, and once as the plume flowed south along the New Jersey coast. The ECOShuttle (a towed-undulating vehicle) carrying a rhodamine fluorometer was able to track these dye patches. An examination of dissolved organic matter transformations that occurred over these two to two and one-half day Lagrangian experiments will be discussed. In addition seasonal distributions of dissolved organic matter distributions will be presented from cruises in June 2003, June 2004 and September 2004 under different river flow and wind conditions.

Chen, R. F.; Gardner, G. B.

2004-12-01

358

Actinide partitioning studies using dihexyl-N,N-diethycarbamolymehtyl phosphonate and dissolved zirconium calcine  

SciTech Connect

A baseline flowsheet capable of partitioning the transuranic (TRU) elements from dissolved zirconium calcines has been developed. The goal of the TRU partitioning process is to remove the TRUs from solutions of dissolved zirconium calcines to below the 10 CFR 61.55 Class A waste limit of 10 nCi/g. Extraction, scrub, strip, and wash distribution coefficients for several elements, including the actinides, were measured in the laboratory by performing equal volume batch contacts. A solvent containing diheyl-N, N- diethylcarbamoylmethyl phosphonate (CMP), tributylphosphate (TBP), and a branched chain hydrocarbon as the diluent were used to develop this process. A non-radioactive zirconium pilot-plant calcine was spiked with the TRUs, U, Tc, or a radioactive isotope of zirconium to simulate the behavior of these elements in actual dissolved zirconium calcine feed. Distribution coefficient data obtained from laboratory testing were used to recommend: (1) solvent composition, (2) scrub solutions capable of selectively removing extracted zirconium while minimizing actinide recycle, (3) optimized strip solutions which quantitatively recover extracted actinides, and (4) feed adjustments necessary for flowsheet efficiency. Laboratory distribution coefficients were used in conjunction with the Generic TRUEX Model (GTM) to develop and recommend a flowsheet for testing in the 5.5-cm Centrifugal Contractor Mockup. GTM results indicate that the recommended flowsheet should remove the actinides from dissolved zirconium calcine feed to below the Class A waste limit of 10 nCi/g. Less than 0.01 wt% of the extracted zirconium will report to the high- activity waste (HAW) fraction using the 0.05 M H{sub 2}C{sub 2}O{sub 4} in 3.0 M HNO{sub 3} scrub, and greater than 99% of the extracted actinides are recovered with 0.001 M HEDPA.

Brewer, K.N.; Herbst, R.S.; Law, J.D.; Garn, T.G.; Tillotson, R.D.; Todd, T.A.

1996-01-01

359

Exchanges and photo-biogeochemical transformation of dissolved organic compounds in Eastern US tidal marsh ecosystems.  

NASA Astrophysics Data System (ADS)

The role of tidal marshes as sources, sinks and/or transformers of biologically important nutrients, carbon and pollutants has been studied in various marsh-estuarine environments and geomorphological settings. Although there is no consensus on the magnitude and direction of marsh-estuary net (particulate and dissolved) organic fluxes, most previous studies suggest that salt marshes export dissolved organic carbon (DOC) to the surrounding estuarine waters. There has been less attention, however, to the influence of transformations on marsh-exported organic carbon composition or "quality". Yet, carbon composition affects a wide variety of estuarine processes, including microbial respiration and photochemistry. Our objectives in this study were to quantify the photo-reactivity and bio-availability of dissolved organic carbon compounds exported from tidal wetlands of the Chesapeake Bay and determine their effects on the optical properties of colored organic matter (CDOM). We quantified DOC bioavailability with two assays of microbial mineralization: the traditional batch incubation approach in which a suspension of DOM and microbial cells (1 m filtrate) was incubated in bottles for 7 d, and a continuous-flow bioreactor approach in which DOC (0.2 m filtrate) was passed through a microbial community that had been pre-established on glass beads from the same source water. Photochemical degradation was measured after a 10h exposure to filtered xenon irradiance simulating midday surface exposure. We measured decreases in CDOM absorption and fluorescence spectra, DOC concentrations, changes in molecular weight distribution, and increases in dissolved inorganic carbon (DIC) and CO2. Results provide important insights on the transformation, fate and cycling of marsh-exported organic compounds, and the role of tidal marsh systems as major regulators of short-scale biological, optical and biogeochemical variability in highly dynamic coastal margins and catchment areas.

Tzortziou, Maria; Neale, Patrick; Megonigal, Patrick; Butterworth, Megan; Jaffe, Rudolf

2010-05-01

360

Attractive surface force in the presence of dissolved gas: a molecular approach.  

PubMed

Despite widespread evidence of the influence of dissolved air on hydrophobic interaction, the mechanisms of observed effects are still unknown. Although some experiments indicate that adsorbed gases can modify the structure of water next to hydrophobic surfaces, gas effects on measured forces have been observed only at large surface separations. Gas-specific depletion of water at a hydrophobic surface has been detected but was not reproduced in subsequent measurements. We use computer simulations to study short-ranged hydrophobic attraction in the absence and presence of dissolved gas and monitor gas adsorption at molecular resolution inaccessible in experiments. Although we observe a significant accumulation of dissolved gases at hydrophobic surfaces, even in supersaturated gas solutions surface concentrations remain too low to induce any significant change in the local structure of water and short-range surface forces. We present direct calculations of the hydrophobic force between model hydrocarbon plates at separations between 1.5 and 4 nm. Although stronger, the calculated solvation force has a similar decay rate as deduced from recent surface force apparatus measurements at a somewhat lower contact angle. Within the statistical uncertainty, short-range attraction is not affected by the presence of dissolved nitrogen, even in supersaturated solution with a gas fugacity as high as 30 atm. Comparisons of the adsorption behavior of N2, O2, CO2, and Ar reveal similar features in contrast to the peculiar suppression of water depletion reported for an Ar solution in a neutron reflectivity experiment. Our calculations reveal a notable difference between pathways to the capillary evaporation of pure water and gas-phase nucleation in confined supersaturated gas solutions. PMID:17979305

Bratko, Dusan; Luzar, Alenka

2007-11-03

361

Risks posed to drinking water aquifers due to leakage of dissolved CO2 in improperly abandoned wellbores  

NASA Astrophysics Data System (ADS)

In order to ensure safe long-term storage of carbon dioxide in geologic formations, the risks posed by improperly abandoned wells must be understood and minimalized. In addition to supercritical and gaseous CO2, brine containing dissolved CO2 poses a leakage risk. CO2 dissolution in brine leads to denser brine and better long-term storage security, but its leakage risk is not zero. Under specific circumstances with formation overpressure or overlying aquifer drawdown, dissolved brine can flow up improperly abandoned wells where it can potentially enter and contaminate drinking water aquifers. The possibility that depressurization in the wellbore may cause CO2 exsolution from brine to form a separate buoyant gas phase is of primary concern. Analytical as well as numerical models are used to evaluate these effects in wellbores as well as to examine the effects of system parameters on brine leakage rates through wellbores. A simple analytical model for uniform density flow is used to evaluate the effects of physical parameters on fluid leakage. It is a useful screening tool for estimating leading order effects of system parameters on leakage of CO2 laden brine. The TOUGH2-ECO2N simulator is also used to evaluate wellbore leakage of dissolved CO2 considering gas exsolution due to pressure, temperature, phase, and salinity changes. Simulations identify the conditions under which a separate gas phase exsolves in a wellbore during CO2 laden brine leakage. Up to 20% of the dissolved brine is found to exsolve in the numerical simulations. This gas accumulates along the top of a drinking water aquifer as a buoyant phase. Simulations also show that the degree of leakage is constrained by the properties of the well, with the permeability of the well being of chief importance. However, at high well permeabilities, simulations show that the geologic formations provide more resistance to flow than the well and constrain leakage rates. Additional analyses are performed in order to see how dissolved CO2 may leak from a wellbore in a geologic system of stratified permeable layers. It is found that the presence of stratigraphy limits the possibility of upward migration of dissolved CO2, whether through overpressure of drawdown.

Ellison, Kirk Matthew

362

Total Maximum Daily Load for Dissolved Cadmium, Dissolved Lead, and Dissolved Zinc in Surface Waters of the Coeur d' Alene River Basin.  

National Technical Information Service (NTIS)

The Environmental Protection Agency (EPA) and Idaho Department of Environmental Quality (DEQ) have issued a final Total Maximum Daily Load (TMDL) for dissolved cadmium, lead, and zinc in surface waters of the Coeur d'Alene Basin. The TMDL contains individ...

2000-01-01

363

Effect of Long-term Reduction and Diel Fluctuation in Dissolved Oxygen on Spawning of Black Crappie, Pomoxis nigromaculatus  

Microsoft Academic Search

Mature black crappies were exposed over winter in the laboratory to constant dissolved oxygen concentrations near 2.5, 4.0, 5.5, and 7.0 mg\\/liter. Starting on 26 April during a simulated spring-to-summer rise in water temperature, some were continued at the original oxygen concentrations while others were subjected to mean diel fluctuations ranging from 0.8 to 1.9 mg O2\\/liter above and below

Anthony R. Carlson; Lawrence J. Herman

1978-01-01

364

The diffusion of dissolved silica in dilute aqueous solution  

NASA Astrophysics Data System (ADS)

The diffusion coefficient of dissolved silica at 25.5 .5 C was determined as a function of concentration using a non-steady-state method whereby agar-gelled solutions containing dissolved silica from 0.09 to 1.50 mM ( pH = 5.5) were placed in contact with distilled water in glass cells. Diffusion coefficients were obtained by measuring the dissolved silica content of the distilled water after a given length of time. The measured diffusion coefficients decreased as a function of increasing dissolved silica concentration, which is thought to reflect an increase in dimeric silica according to the equilibrium: 2 Si ( OH ) 4 = Si 2 O ( OH ) 6 + H 2 O . The tracer diffusion coefficients for Si(OH) 4 and Si 2 O(OH) 6 and an association constant for the above reaction were determined by fitting the following equation to the experimental data: D obs = D monomer + (1 - ) D dimer where is the fraction of total dissolved silica which is Si(OH) 4 . The best fit yielded tracer D 's for Si(OH) 4 and Si 2 O(OH) 6 of 2.2 and 1.0 (in units of 10 -5 cm 2 sec -1 ), respectively, and an association constant of 330.

Applin, Kenneth R.

1987-08-01

365

Removal of dissolved organic matter by anion exchange: effect of dissolved organic matter properties.  

PubMed

Ten isolates of aquatic dissolved organic matter (DOM) were evaluated to determine the effect that chemical properties of the DOM, such as charge density, aromaticity, and molecular weight, have on DOM removal by anion exchange. The DOM isolateswere characterized as terrestrial, microbial, or intermediate humic substances or transphilic acids. All anion exchange experiments were conducted using a magnetic ion exchange (MIEX) resin. The charge density of the DOM isolates, determined by direct potentiometric titration, was fundamental to quantifying the stoichiometry of the anion exchange mechanism. The results clearly show that all DOM isolates were removed by anion exchange; however, differences among the DOM isolates did influence their removal by MIEX resin. In particular, MIEX resin had the greatest affinity for DOM with high charge density and the least affinity for DOM with low charge density and low aromaticity. This work illustrates that the chemical characteristics of DOM and solution conditions must be considered when evaluating anion exchange treatment for the removal of DOM. PMID:18939582

Boyer, Treavor H; Singer, Philip C; Aiken, George R

2008-10-01

366

Dissolved mercury behaviour in the Saint Lawrence estuary  

NASA Astrophysics Data System (ADS)

Dissolved mercury concentrations have been measured in the waters of the St Lawrence estuary. The typical concentration of the riverine end-member is 12030 p M; the oceanic end-member samples exhibit a mean mercury concentration of 24 p M. The graphical pattern of the relationship between mercury concentration and salinity shows a departure from a dilution line. We suggest that a removal of mercury from the dissolved phase during the estuarine mixing is responsible for this observation. Based on the results, the actual input of dissolved mercury from the St Lawrence River to the Gulf is evaluated to be approximately 052 T a -1.

Cossa, Daniel; Gobeil, Charles; Courau, Philippe

1988-02-01

367

Dissolved gas concentrations of the geothermal fluids in Taiwan  

NASA Astrophysics Data System (ADS)

Taiwan, a geologically active island, is located on the boundary of the Philippine Sea Plate and the Eurasian Plate. High heat flow and geothermal gradient generated by the complex collision and orogeny, warm up the meteoric water and/or the ground water. The heated water becomes geothermal fluids. In previous studies, researchers tried to categorize hot springs based on the appearance, chemical compositions and lithological areas. Because of the chemical inertness, the concentrations and isotopic composition of dissolved noble gases are good indicators of the mantle degassing, geothermal conditions, and so on. In this study, 55 hot springs were collected from different tectonic units. It is the first time to systematically study the hot springs in Taiwan in terms of dissolved gases. Hot spring water is sampled and stored in pre-evacuated glass bottles for analyzing gas compositions. The abundances of noble gases were determined by a quadrupole mass spectrometer based on the isotope dilution technique. Samples with glass vials are introduced to RAD 7 and GC for dissolved Rn and major dissolved gases analyses. Furthermore, helium isotopic ratios and helium-neon ratios are measured on a conventional noble gas mass spectrometer. For hydrochemistry analysis, water samples are analyzed by IC, ICP-MS and titration. We can classify the hot springs samples into three major groups from main anion concentration data; and then, subdivide them into nine minor groups by cation concentration data. Moreover, according to major dissolved gases compositions, three major gas components: CH4, N2 and CO2, are identified. Dissolved noble gases provided more detailed clues about hot springs sources in Taiwan, such as the degree of mixing between meteoric water and deep-source water, which will be further discussed in this study.

Chen, Ai-Ti; Yang, Tsanyao Frank

2010-05-01

368

Dissolved iron in the Southern Ocean (Atlantic sector)  

NASA Astrophysics Data System (ADS)

We report a comprehensive dataset of dissolved iron (Fe) comprising 482 values at 22 complete vertical profiles along a 1 latitudinal section at the Zero meridian. In addition a shorter high resolution (0009') surface section of the southernmost part of the transect (6600'-6935'S) is presented. Within the upper surface mixed layer the concentrations of dissolved Fe vary between 0.1 and 0.3 nM. An inverse trend versus fluorescence suggests significant Fe removal by plankton blooms. Vertical mixing and upwelling are the most important supply mechanisms of iron from deep waters to the upper surface mixed layer. At lower latitude (42S) there is a distinct maximum of 0.6-0.7 nM in the 2000-3000 m depth range due to inflow of North Atlantic Deep Water. In one region (55S) elevated dissolved Fe found in the surface mixed layer is ascribed to the recent deposition of aeolian dust originating from South America. Close to the Antarctic continent there is an indication of Fe supply in surface waters from icebergs. In the deep waters there is a strong indication of a hydrothermal plume of dissolved Fe and Mn over the ridge in the Bouvet region (52-56S). In the Weddell Gyre basin the dissolved Fe in the deep water is 0.470.16 nM in the eastward flow at 56-62S and is lower with a value of 0.340.14 nM in the westward flow at high 62-69S latitude. At the edge of the continental ice-sheet on the prime meridian, the continental margin of the Antarctic continent appears to be lesser source of dissolved Fe than in any other place in the world; this is likely because it is unique in being overlain by the extending continental ice-sheet that largely prevents biogeochemical cycling.

Klunder, M. B.; Laan, P.; Middag, R.; De Baar, H. J. W.; van Ooijen, J. C.

2011-12-01

369

New potentiomentric dissolved oxygen sensors in thick film technology  

Microsoft Academic Search

New designed dissolved oxygen potentiometric sensors in thick film technology based in the use of RuO2 as active material and TiO2 or polyisoftalamide diphenylsulphone (PIDS) as membranes have been developed. TiO2-coated RuO2 electrodes showed a linear response as a function of the logarithm of the dissolved oxygen concentration in the 0.58ppm range (log[O2], ?4.82 to ?3.60; concentration of O2 in

Ramn Mart??nez-Mez; Juan Soto; Josefa Lizondo-Sabater; Eduardo Garc??a-Breijo; Luis Gil; Javier Ibez; Isabel Alcaina; Silvia Alvarez

2004-01-01

370

Iron oxides, dissolved silica, and regulation of marine phosphate concentration  

NASA Astrophysics Data System (ADS)

Phosphorous concentrations in iron oxide-rich sediments reflect orthophosphate levels in the water column from which iron oxides precipitated. Sediment P/Fe ratios are also strongly influenced by the concentrations of dissolved species that inhibit orthophosphate-to-ferrihydrite sorption, most notably silica. It may, therefore, be possible to use P/Fe ratios in iron oxide-rich sediments to estimate past dissolved P concentrations, if one considers the evolution of the silica cycle. A compilation of Fe and P data in iron oxide-rich sediments through time reveals an increase in P/Fe ratios after the Jurassic. We propose that this trend indicates evolution of the iron-oxide phosphate removal mechanism caused by decreasing levels of sorption inhibition by dissolved silica. The large difference in P/Fe ratios in Cenozoic versus older iron-oxide rich sediments can be linked with Si drawdown caused by the proliferation of siliceous plankton in the Cretaceous. There is also a late Mesozoic or Cenozoic increase in V/Fe ratios, which provides additional evidence for lower ferrihydrite anion sorption efficiency prior to diatom radiation. P/Fe ratios in iron oxide-rich sediments from the early and middle Phanerozoic are comparable to the ratios in iron formations previously presented as evidence for an early Precambrian phosphate crisis (Bjerrum and Canfield, 2002, Nature, 417:159-162). Given the compelling evidence for higher Si concentrations in the Precambrian compared to the Phanerozoic and dissolved P concentrations comparable to modern levels throughout the Phanerozoic, the presented trend of P/Fe ratios suggests dissolved P concentrations were higher in Precambrian than Phanerozoic oceans. High dissolved P levels in the Precambrian may have been linked to inhibited carbonate fluorapatite (CFA) formation as a result of persistently high levels of carbonate supersaturation. Carbonate ion substitution into CFA scales with the ambient carbonate ion activity and increases the solubility of the CFA. Substitution of the carbonate ion into the fluorapatite structure, therefore, results in an exponential increase in the levels of dissolved P needed for CFA precipitation. Elevated dissolved P concentrations in Precambrian oceans likely resulted in nitrogen-limited primary production on geological time scales.

Planavsky, N.; Reinhard, C.; Lyons, T.

2008-12-01

371

Dissolved-oxygen quenching of in-situ fluorescence measurements  

NASA Astrophysics Data System (ADS)

In-situ fluorescence measurements of aromatic organic ground water contaminants do not always agree with gas chromatographic methods. Dissolved oxygen quenching of fluorescence may be an interferant in field measurements. Two standard fluorescent aromatics, quinine sulfate and naphthalene, were evaluated in this study. Over the range of dissolved oxygen concentrations expected to be encountered in the field, no effects of oxygen quenching on fluorescence of these compounds was observed. Quenching of quinine sulfate fluorescence by sodium chloride was observed using this system. Sodium chloride quenching was shown to follow the Stern-Volmer relation.

Chudyk, Wayne; Tonaszuck, David; Pohlig, Kenneth

1993-04-01

372

Large fluctuations of dissolved oxygen in the Indian and Pacific oceans during Dansgaard-Oeschger oscillations caused by variations of North Atlantic Deep Water subduction  

Microsoft Academic Search

Paleoclimate records from glacial Indian and Pacific oceans sediments document millennial-scale fluctuations of subsurface dissolved oxygen levels and denitrification coherent with North Atlantic temperature oscillations. Yet the mechanism of this teleconnection between the remote ocean basins remains elusive. Here we present model simulations of the oxygen and nitrogen cycles that explain how changes in deepwater subduction in the North Atlantic

Andreas Schmittner; Eric D. Galbraith; Steven W. Hostetler; Thomas F. Pedersen; Rong Zhang

2007-01-01

373

Modeling the liquid-phase oxidation of hydrocarbons over a range of temperatures and dissolved oxygen concentrations with pseudo-detailed chemical kinetics  

Microsoft Academic Search

The ability of pseudo-detailed chemical kinetic modeling to simulate the oxidation behavior of Exxsol D-80, a paraffin blend whose oxidative characteristics are representative of severely hydrotreated jet fuels, is assessed. The effects of temperature and initial dissolved O2 concentration on oxidation are considered. A 17-step pseudo-detailed mechanism is shown to provide reasonable simulations of Exxsol D-80 oxidation over a range

Nicholas J. Kuprowicz; Jamie S. Ervin; Steven Zabarnick

2004-01-01

374

Reduced Dissolved Oxygen Test System for Marine Organisms.  

National Technical Information Service (NTIS)

A flow-through test system was designed to examine minimum dissolved oxygen (D.O.) requirements of marine animals. The system provides up to six treatment concentrations between 0.3 mg D.O./l and saturation. Sea water is degassed in a vacuum-evacuated pac...

D. C. Miller D. E. Body J. C. Sinnett S. L. Poucher J. Sewall D. J. Sleczkowski

1994-01-01

375

Dissolved oxygen and thermal regimes of a Ugandan crater lake  

Microsoft Academic Search

This paper quantifies the temporal pattern of thermal stratification and deoxygenation in Lake Nkuruba, a small (3 ha), deep (maximum depth = 38 m) crater lake in western Uganda. Dissolved oxygen penetrated to an average depth of 9 m and a maximum depth of 15 m below which the lake was permanently anoxic over the 2 years of study. Although

Lauren J. Chapman; Colin A. Chapman; Thomas L. Crisman; Frank G. Nordlie

1998-01-01

376

Modeling Dissolved Oxygen in a Dredged Lake Erie Tributary  

Microsoft Academic Search

A two-dimensional numerical model was developed to study dissolved oxygen (DO) kinetics in a dredged Lake Erie tributary. The model design was aimed to specifically address the fact that many tributaries to the Great Lakes are dredged periodically for navigation, and that resultant changes in morphology and hydraulics can have significant impacts on DO. Due to the greater depths caused

Jagjit Kaur; Gopi Jaligama; Joseph F. Atkinson; Joseph V. DePinto; Adrienne D. Nemura

2007-01-01

377

Predicting Diel Dissolved Oxygen Dynamics in the Carson River, Nevada  

Microsoft Academic Search

The Carson River originates in eastern Alpine County California, flows northeast into western Nevada through Carson City, and terminates in the Carson Sink. Elevated nutrient levels from agricultural return flows allow for excess attached algal (periphyton) growth. Periods of low flow, coupled with an abundance of periphyton, harbor an environment capable of producing dissolved oxygen concentrations less than 5 mg

Z. B. Latham; J. J. Warwick; C. H. Fritsen

2005-01-01

378

Dependence of riverine nitrous oxide emissions on dissolved oxygen levels  

NASA Astrophysics Data System (ADS)

Nitrous oxide is a potent greenhouse gas, and it destroys stratospheric ozone. Seventeen per cent of agricultural nitrous oxide emissions come from the production of nitrous oxide in streams, rivers and estuaries, in turn a result of inorganic nitrogen input through leaching, runoff and sewage. The Intergovernmental Panel on Climate Change and global nitrous oxide budgets assume that riverine nitrous oxide emissions increase linearly with dissolved inorganic nitrogen loads, but data are sparse and conflicting. Here we report measurements over two years of nitrous oxide emissions in the Grand River, Canada, a seventh-order temperate river that is affected by agricultural runoff and outflow from a waste-water treatment plant. Emissions were disproportionately high in urban areas and during nocturnal summer periods. Moreover, annual emission estimates that are based on dissolved inorganic nitrogen loads overestimated the measured emissions in a wet year and underestimated them in a dry year. We found no correlations of nitrous oxide emissions with nitrate or dissolved inorganic nitrogen, but detected negative correlations with dissolved oxygen, suggesting that nitrate concentrations did not limit emissions. We conclude that future increases in nitrate export to rivers will not necessarily lead to higher nitrous oxide emissions, but more widespread hypoxia most likely will.

Rosamond, Madeline S.; Thuss, Simon J.; Schiff, Sherry L.

2012-10-01

379

Attributions About Rape in a Continuum of Dissolving Marital Relationships  

Microsoft Academic Search

This study explored what actions taken by married women to dissolve their marital relationships might result in different attributions about husband rape perpetration. A sample of 233 undergraduates (120 men, 114 women) read one of three rape scenarios in which a married woman changed her marital status with her husband perpetrator (moved out, legally separated, or divorced). Two other scenarios

CORRIE A. EWOLDT; CANDICE M. MONSON; JENNIFER LANGHINRICHSEN-ROHLING

2000-01-01

380

Dissolved Organic Carbon Export by the Yukon River  

Microsoft Academic Search

Spatial and temporal variability of dissolved organic carbon (DOC) in surface waters associated with the Yukon River are being studied to better define processes controlling DOC in this system and to examine the effects of warmer temperatures on C export from large permafrost dominated watersheds. The Yukon River Basin is experiencing melting permafrost, drying of upland soils and changing wetland

G. Aiken; R. Striegl; M. Dornblaser; P. Raymond; K. Wickland

2005-01-01

381

Dissolving Carboxylic Acids and Primary Amines on the Overhead Projector  

ERIC Educational Resources Information Center

|Liquid carboxylic acids (or primary amines) with limited solubility in water are dissolved by addition of aqueous sodium hydroxide (or hydrochloric acid) on the stage of an overhead projector using simple glassware and very small quantities of chemicals. This effective and colorful demonstration can be used to accompany discussions of the

Solomon, Sally D.; Rutkowsky, Susan A.

2010-01-01

382

DISSOLVED OXYGEN AND OXIDATION-REDUCTION POTENTIALS IN GROUND WATER  

EPA Science Inventory

Water samples were collected from various depths in a pristine sand and gravel water table aquifer at monthly intervals over a period of one year. Dissolved oxygen concentrations were near saturation 9 feet below the water table and decreased to nearly zero at 78 feet below the w...

383

Biological Uptake of Dissolved Silica in the Amazon River Estuary  

Microsoft Academic Search

Approximately 25 percent of the dissolved silica carried by the Amazon River is depleted through diatom production in the inner estuary. Annual production of opaline frustules is estimated to be 15 million tons. However, few diatoms accumulate in modern shelf sediments and chemical recycling appears to be slight. Instead, many frustules apparently are transported landward into the river system, where

John D. Milliman; Edward Boyle

1975-01-01

384

Electrochemical determination of dissolved uranium in Krka River estuary.  

PubMed

The applicability of the previously developed method for electrochemical determination of dissolved uranium concentration has been tested on natural water samples taken from the Krka river estuary during various seasons and along different depth profiles. The method is based on the following treatment of the sample: destroying the uranyl-carbonato complexes by adjusting the pH to 3, enabling the formation of adsorbable uranyl-hydroxo complexes by adjusting the pH to 6.5-7.0 and measurement by cathodic stripping voltammetry technique. As the signal of the dissolved uranium reduction is sometimes masked by the signal of the matrix of the sample, a resolution enhancement including digestion and/or deconvolution has to be applied. The measured concentration of dissolved uranium varies in the range from 0.4 to 3.3 x 10(-8) mol l-1, corresponding to the data found in the literature. The depth profile of dissolved uranium concentration distributions shows conservative behaviour. The X-ray fluorescence spectroscopy (XRF) confirmed the applicability of the method, yet pointing out to its limitations caused by the matrix of the solution. PMID:11337837

Djogi?, R; Pizeta, I; Branica, M

2001-06-01

385

Dissolved Oxygen Conditions in Northern Gulf of Mexico Estuaries  

Microsoft Academic Search

Because deficient dissolved oxygen (DO) levels may have severe detrimental effects on estuarine and marine life, DO has been widely used as an indicator of ecological conditions by environmental monitoring programs. The U.S. EPA's Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) monitored DO conditions in the estuaries of the Gulf of Mexico from 1991 to 1994. DO was measured

Virginia D. Engle; J. Kevin Summers; John M. Macauley

1999-01-01

386

NET DISSOLVED ORGANIC CARBON PRODUCTION IN RECIRCULATING SALMONID CULTURE SYSTEM  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ozonating a coldwater recirculating system (RAS) can help control the accumulation of fine suspended solids, micro-organisms, and components of dissolved organic carbon (DOC) that can negatively impact fish health and production efficiency. Ozone can oxidize relatively large non-biodegradable organ...

387

The Placebo Effect: Dissolving the Expectancy Versus Conditioning Debate  

ERIC Educational Resources Information Center

The authors review the literature on the 2 main models of the placebo effect: expectancy theory and classical conditioning. A path is suggested to dissolving the theoretical impasse that has long plagued this issue. The key is to make a clear distinction between 2 questions: What factors shape placebo effects? and What learning mediates the

Stewart-Williams, Steve; Podd, John

2004-01-01

388

Dissolved oxygen in lower Hudson Estuary: 1978--93  

Microsoft Academic Search

During summer months, dissolved oxygen (DO) concentrations in the lower Hudson estuary were usually lower than atmospheric equilibrium values. Distributions of DO along the axis of the estuary can be described by three general characteristics. Firstly, surface and bottom values lie on a single trend when plotted against salinity. Secondly, maximum DO concentrations were observed 50--75 km upstream of Manhattan

Jordan F. Clark; H. James Simpson; Richard F. Bopp; Bruce L. Deck

1995-01-01

389

The Raman analysis of films cast from dissolved feather keratin  

Microsoft Academic Search

Raman spectroscopy was used to characterize films cast from dissolved feather keratin. Spectra obtained from the films were found to be very similar to those of the feather components from which they were derived. The protein structure of the films was dominated by ?-sheet conformation with possibly more disordered protein content and slightly less disulfide cross-linking compared to the feather.

J. S. Church; A. J. Poole; A. L. Woodhead

2010-01-01

390

Climate Variability, Dissolved Organic Carbon, UV Exposure, and Amphibian Decline  

Microsoft Academic Search

Increasing levels of UV radiation represent a potential threat to aquatic organisms in a wide range of environments, yet controls on in situ variability on UV exposure are relatively unknown. The primary control on the penetration of UV radiation in surface water environments is the amount of photoreactive dissolved organic carbon (DOC). Consequently, biogeochemical processes that control the cycling of

P. D. Brooks; C. M. O'Reilly; S. Diamond; S. Corn; E. Muths; K. Tonnessen; D. H. Campbell

2001-01-01

391

MICRO GASOMETRIC DETERMINATION OF DISSOLVED OXYGEN AND NITROGEN  

Microsoft Academic Search

For polluted water and many biological fluids the Winkler method for the de termination of dissolved oxygen may easily become unreliable, or inapplicable. This difficulty can be avoided by using gasometnic methods. We describe below such a method for the determination of oxygen (and nitrogen) in one cubic centimeter of water. It has been used extensively under field conditions to

P. F. SCHOLANDER; L. VAN DAM; C. LLOYD CLAFF; J. W. KANWISHER

392

TOTAL DISSOLVED AND BIOAVAILABLE METALS AT LAKE TEXOMA MARINAS  

EPA Science Inventory

Dissolved metals in water and total metals in sediments have been measured at marina areas in Lake Texoma during June 1999 to October 2001, and October 2001, respectively. The metals most often found in the highest concentrations in marina water were Na and Ca, followed by Mg an...

393

Detoxification of Dissolved SO2 (Bisulfite) by Terricolous Mosses  

Microsoft Academic Search

? Background and Aims The widespread calcifuge moss Pleurozium schreberi is moderately tolerant of SO2, whereas Rhytidiadelphus triquetrus is limited to calcareous soils in regions of the UK that were strongly affected by SO2 pollution in the 20th century. The proposition that tolerance of SO2 by these terricolous mosses depends on metabolic detoxification of dissolved bisulfite was investigated. ? Methods

BHAGAWAN BHARALI; JEFFREY W. BATES

2006-01-01

394

EFFECTS OF SUSPENDED SEDIMENTS ON PHOTOLYSIS RATES OF DISSOLVED POLLUTANTS  

EPA Science Inventory

Data are presented concerning the effects of suspended sediments upon photolysis rates of dissolved ultraviolet (u.v.) absorbing pollutants. The malachite green leucocyanide actinometer was found to be a convenient and sensitive device for measurement of solar u.v. radiation (abo...

395

Dissolved organic carbon in a northern boreal landscape  

Microsoft Academic Search

I examined concentrations and fluxes of dissolved organic carbon (DOC) in precipitation, upland forest throughfall, stemflow and soil water, peatland pore water, beaver ponds, and streams from May to September 1994 in the BOREAS Northern Study Area, near Thompson, Manitoba, Canada. Concentrations of DOC in precipitation were large (8 mg L?1) compared to other boreal locations, possibly associated with a

T. R. Moore

2003-01-01

396

Dissolved organic carbon in a northern boreal landscape  

Microsoft Academic Search

I examined concentrations and fluxes of dissolved organic carbon (DOC) in precipitation, upland forest throughfall, stemflow and soil water, peatland pore water, beaver ponds, and streams from May to September 1994 in the BOREAS Northern Study Area, near Thompson, Manitoba, Canada. Concentrations of DOC in precipitation were large (8 mg L-1) compared to other boreal locations, possibly associated with a

T. R. Moore

2003-01-01

397

Dissolved organic carbon in a northern boreal landscape  

Microsoft Academic Search

I examined concentrations and fluxes of dissolved organic carbon (DOC) in precipitation, upland forest throughfall, stemflow and soil water, peatland pore water, beaver ponds, and streams from May to September 1994 in the BOREAS Northern Study Area, near Thompson, Manitoba, Canada. Concentrations of DOC in precipitation were large (8 mg L1) compared to other boreal locations, possibly associated with a

T. R. Moore

2003-01-01

398

REMOVAL OF HUMICSUBSTANCES AND ALGAE BY DISSOLVED AIR FLOTATION  

EPA Science Inventory

Dissolved air flotation (DAF) is used in place of conventional gravity settling as a means to separate low density floc particles from water. The following objectives were: (1) to compare DAF to conventional water treatment of coagulation-flocculation followed by gravity settling...

399

Removal of dissolved estrogen in sewage effluents by ?-cyclodextrin polymer  

Microsoft Academic Search

Substances with estrogenic activity are found in effluents of municipal sewage plants and dairy farms. These effluents have the potential to induce feminization in male fish. In this study, cyclodextrin polymers (CDPs) that are insoluble in both polar and non-polar solvents were selected for the removal of dissolved estrogens in the effluent of a municipal sewage plant. The removal capacity

Kyoko Oishi; Ayumi Moriuchi

2010-01-01

400

Electrochemical determination of dissolved uranium in Krka river estuary  

Microsoft Academic Search

The applicability of the previously developed method for electrochemical determination of dissolved uranium concentration has been tested on natural water samples taken from the Krka river estuary during various seasons and along different depth profiles. The method is based on the following treatment of the sample: destroying the uranyl-carbonato complexes by adjusting the pH to 3, enabling the formation of

R Djogi?; M Branica

2001-01-01

401

Rapidly dissolving silk protein microneedles for transdermal drug delivery  

Microsoft Academic Search

This paper presents rapidly dissolving fibroin microneedles for the first time. A reverse PDMS microneedles mold was first created and drug-contained fibroin solution was poured into this reverse PDMS microneedles mold. Fibroin microneedles were successfully fabricated after drying and detaching the solidified fibroin structure from the PDMS mold. These fibroin microneedles serve as a matrix to incorporate drug molecules while

Xueqiu You; James Jungho Pak; Jong-hyeon Chang

2010-01-01

402

Dissolved-Solids Budget of Lake Okeechobee, Florida.  

National Technical Information Service (NTIS)

Lake Okeechobee is a major surface-water storage facility for south Florida. A dissolved-solids budget for Lake Okeechobee was computed for October 1964 to September 1974, a 10-year budget period. Calculations were based on records of daily discharge, dai...

D. V. Maddy

1978-01-01

403

DISSOLVED OXYGEN MEASUREMENTS IN INDIANA STREAMS DURING URBAN RUNOFF  

EPA Science Inventory

This short term research project was undertaken for the purpose of locating and identifying sites where potential dissolved oxygen (D.O.) impacts exist during periods of urban runoff, and providing the necessary information to justify more extensive D.O. model verification studie...

404

The partitioning of fenvalerate to natural dissolved organic matter  

Microsoft Academic Search

The degree of association of the pyrethroid insecticide fenvalerate to dissolved organic matter (DOM) was measured with the reverse-phase partition coefficient (Krp) using Sep-Paks. Natural DOM of four size fractions ranging from 1 K molecular weight up to 1 ?m was isolated from Jack Lake and Luther Marsh in Ontario, Canada, and compared to the commercial DOM substitute Aldrich humic

Gary T. Fan; B. Kent Burnison; Keith R. Solomon

1997-01-01

405

REDUCED DISSOLVED OXYGEN TEST SYSTEM FOR MARINE ORGANISMS  

EPA Science Inventory

A flow-through test system was designed to examine minimum dissolved oxygen (D.O.) requirements of marine animals. he system provides up to six treatment concentrations between 0.3 mg D.O./I and saturation. ea water is degassed in a vacuum-evacuated packed column and the treatmen...

406

Dissolved oxygen concentration profiles in a production-scale bioreactor  

Microsoft Academic Search

A five-compartment model for the liquid flow and the oxygen transfer into the liquid phase of a large-scale bioreactor is presented. The aim of the model is to predict the following reactor operating variables: 1) the overall oxygen transfer capacity of the reactor; 2) the local liquid dissolved oxygen concentrations, for estimation of bad aerated zones which can introduce negative

N. M. G. Oosterhuis; N. W. F. Kossen

1984-01-01

407

FIELD MEASUREMENT OF DISSOLVED OXYGEN: A COMPARISON OF METHODS  

EPA Science Inventory

The ability to confidently measure the concentration of dissolved oxygen (D.O.) in ground water is a key aspect of remedial selection and assessment. Presented here is a comparison of the commonly practiced methods for determining D.O. concentrations in ground water, including c...

408

Water Quality Monitoring Using Total Dissolved Solids Measurements  

Microsoft Academic Search

2 Special Steel Complex, Physics laboratories, 9-11 Gaesti Ave., 130087, Targoviste, Romania Total Dissolved Solids (TDS) are used, together with other parameters, to classify the river water concerning their quality. The rapid increase of pollution in Dambovita County, due to the industrial processes, thermal power station and domestic sewage, modify the quality of Ialomita river along the county. So, it

CLAUDIA STIHI; ION V. POPESCU; SIMONA APOSTOL; GHEORGHE VLAICU

409

Total Dissolved Solids: Determination, Sources, Effects, and Removal  

Microsoft Academic Search

Many parameters may be used to measure the deterioration of water quality. One very important parameter is total dissolved solids (TDS). An increase in TDS beyond acceptable levels can have a significant impact on municipal, industrial, and agricultural use of water. In this review an overview of the problem of high TDS levels is given. Factors related to TDS which

Joseph H. Sherrard; Donald R. Moore; Theo A. Dillaha

1987-01-01

410

Atmospheric inputs and river transport of dissolved substances  

Microsoft Academic Search

Several different types of behaviour can be observed for elements between atmospheric input and river transport including very limited chemical or biological reactivity (CI-, in most cases), change of speciation (C, N, P), recycling to atmosphere (C, N, S, K), increase of dissolved contents through weathering (Si, Ca, Mg, Na), and build-up in soil or vegetation (C, N, P, Ca,

MICHEL MEYBECK

1983-01-01

411

Agricultural Practices Influence Dissolved Nutrients Leaching through Intact Soil Cores  

Microsoft Academic Search

high water table was set in the Netherlands (Breeuwsma et al., 1995). Agricultural practices such as tillage, crop- Nitrogen and P leaching from agricultural land to ground water ping systems, and fertilizer applications influence soil poses a threat to water quality, but it may be possible to control nutrient concentrations and drainage rates, leading us dissolved nutrient leaching by choosing

You Jiao; William H. Hendershot; Joann K. Whalen

2004-01-01

412

Removal properties of dissolved boron by glucomannan gel.  

PubMed

Boron ions have long been known to form complexes with the cis-diol group of a polysaccharide. Konjac glucomannan (KGM) which is one of polysaccharides was used to remove dissolved boron in this study. KGM forms a complex with boron, but does not remove boron from contaminated waters as well as other polysaccharides because of its high water solubility. Therefore, the removal efficiencies of dissolved boron were examined using both an insoluble KGM gel and KGM semi-gel. The former did not remove dissolved boron, but the latter did. The difference in the ability of boron removal was due to the presence of diol group inside. KGM loses free diol group during the process of gelation. On the other hand, the semi-gel gelated only surface layer in water has diol group inside. The boron removal capacity of the semi-gel was highest at pHs?11, when the boron species is present as B(OH)4(-). The capacity was slightly increased by the addition of Al, Ca and Mg under high pH conditions. This was due to co-precipitation of boron with Ca dissolved from the semi-gel. The boron adsorbed to the semi-gel easily was desorbed under low pH conditions and the hysteresis was not found. PMID:23260255

Oishi, Kyoko; Maehata, Yugo

2012-12-20

413

The Placebo Effect: Dissolving the Expectancy Versus Conditioning Debate  

ERIC Educational Resources Information Center

|The authors review the literature on the 2 main models of the placebo effect: expectancy theory and classical conditioning. A path is suggested to dissolving the theoretical impasse that has long plagued this issue. The key is to make a clear distinction between 2 questions: What factors shape placebo effects? and What learning mediates the

Stewart-Williams, Steve; Podd, John

2004-01-01

414

Investigation of runoff generation from anthropogenic sources with dissolved xenobiotics  

Microsoft Academic Search

In the experimental Mess basin (35 km2, Luxembourg) dissolved xenobiotics in surface water are used to study the influences of anthropogenic sources like separated sewer systems on runoff generation. Emerging contaminants like pharmaceuticals are of growing interest because of their use in large quantities in human and veterinary medicine. The amounts reaching surface waters depend on rainfall patterns, hydraulic conditions,

A. Krein; J. Pailler; C. Guignard; J. Iffly; L. Pfister; L. Hoffmann

2009-01-01

415

Chloride Analysis of RFSA Second Campaign Dissolver Solution  

SciTech Connect

The dissolver solution from the second RFSA campaign was analyzed for chloride using the recently-developed turbidimetric method. Prior to chloride removal in head end, the solution contained 1625 ppm chloride. After chloride removal with Hg(I) and prior to feeding to solvent extraction, the solution contained only 75 ppm chloride. This report discusses those analysis results.

Holcomb, H.P.

2001-05-17

416

Dissolved free amino acids in southern California coastal waters  

Microsoft Academic Search

The dissolved fret amino acids (DFAA) in seawater samples from an inshore arca near a large submarine sewage outfall and from an inshore area relatively rcmotc from any major outfall were compared. At both sites, surface waters contained DFAA levels of about 115 pg\\/litcr (ca. 1 pmole\\/liter), about twice the value found in surface samples from other parts of the

M. E. CLARK; G. A. JACKSON; W. J. NORTH

1972-01-01

417

CONDUCTOMETRIC CHARACTERIZATION OF DISSOLVED HUMIC MATERIALS. (R828158)  

EPA Science Inventory

Conductometric replacement titrations of humic and fulvic acids dissolved in a slight excess of hydroxide were carried out with standard acid. The slope of the titration curve corresponding to the protonation of humate/fulvate was related to the electrophoretic mobility of the...

418

Investigating Factors that Affect Dissolved Oxygen Concentration in Water  

ERIC Educational Resources Information Center

|Describes activities that demonstrate the effects of factors such as wind velocity, water temperature, convection currents, intensity of light, rate of photosynthesis, atmospheric pressure, humidity, numbers of decomposers, presence of oxidizable ions, and respiration by plants and animals on the dissolved oxygen concentration in water. (MA)|

Jantzen, Paul G.

1978-01-01

419

Salmonid Bioassay of Supersaturated Dissolved Air in Water.  

National Technical Information Service (NTIS)

Tests were conducted in shallow (0.25 m) and deep (2.5 m) tanks of water at 10C with concentrations of dissolved atmospheric gas ranging from 100% to 127% of air saturation to determine the lethal and sublethal effects on juvenile fall chinook salmon (Onc...

E. Dawley B. Monk M. Schiewe F. Ossiander W. Ebel

1976-01-01

420

The Placebo Effect: Dissolving the Expectancy Versus Conditioning Debate  

Microsoft Academic Search

The authors review the literature on the 2 main models of the placebo effect: expectancy theory and classical conditioning. A path is suggested to dissolving the theoretical impasse that has long plagued this issue. The key is to make a clear distinction between 2 questions: What factors shape placebo effects? and What learning mediates the placebo effect? The reviewed literature

Steve Stewart-Williams; John Podd

2004-01-01

421

Effects of photodegradation of dissolved organic matter on the binding of benzo(a)pyrene.  

PubMed

Dissolved organic matter (DOM) in natural waters can bind various organic pollutants, and the affinity of this binding is strongly influenced by the chemical characteristics of the DOM and water pH. This study examined the effects of photochemically induced alteration of the DOM's chemical properties and water pH on the binding of benzo(a)pyrene (BaP). Time- and pH-series of solar-simulated irradiations were performed on a natural water sample and aqueous DOM solutions prepared from aquatic and soil humic substances. The binding affinity of BaP, expressed as a partition coefficient of a compound to DOM, decreased substantially after the DOM samples were irradiated over environmentally relevant radiation doses and pH ranges. The lowering of the pH due to the photoproduction of acidic products often partly offsets the reduction of the binding affinity caused by direct photoalteration of the DOM's chemical structure. The decrease of the binding affinity, after correction for the photoinduced pH change, was positively correlated with the decrease in the molecular weight and the aromaticity of the DOM in the course of irradiation. Increasing O(2) abundance accelerated the decrease of the binding affinity as a result of enhanced DOM photodegradation. Visible light played a more important role in reducing the molecular weight and aromaticity of the DOM than in reducing the content of dissolved organic carbon (DOC) via photoremineralization while the reverse was true for UV radiation, indicating that photochemical reduction of the binding affinity may occur in natural waters at depths greater than UV radiation can reach. A decrease of the affinity of DOM for binding BaP will increase the free dissolved fraction of BaP and thus its availability and toxicity to aquatic organisms. The results from this study may have similar implications for organic pollutants other than BaP. PMID:16406054

Lou, Tao; Xie, Huixiang; Chen, Guohua; Gagn, Jean-Pierre

2006-01-10

422

Graphite fuels combustion off-gas treatment options  

Microsoft Academic Search

Scenarios for burning bulk graphite and for burning crushed fuel particles from graphite spent nuclear fuels have been considered. Particulates can be removed with sintered metal filters. Subsequent cooling would then condense semi-volatile fission products into or onto a particulate. These particulates would be trapped by a second sintered metal filter or downstream packed bed. A packed bed scrub column

R. J. Kirkham; R. E. Lords

1993-01-01

423

Johnston vows to head off gas proration ban  

SciTech Connect

This paper reports that Sen. Bennett Johnston (D-La.) has vowed if Congress enacts an omnibus energy bill in the fall, it will not include a restriction on states' rights to proration natural gas production. Johnston, Senate energy committee chairman, will lead Senate conferees in their negotiations with members of the House of Representatives. The House energy bill has an antiproration amendment. The Senate's bill does not. Oklahoma's and Texas' recent actions to proration gas production prompted the federal legislation.

Not Available

1992-06-29

424

TREATMENT OF MERCURY TARGET OFF-GAS AT SNS  

Microsoft Academic Search

The Spallation Neutron Source (SNS) is the first operational spallation source to use liquid Mercury as a target material. This paper describes the treatment system to remove volatile spallation products from a Helium purge stream that emanates from the Mercury target and adjustments made to achieve design goals in response to phenomena experienced during initial operations. The Helium stream is

Joe R DeVore; David W Freeman

2007-01-01

425

Hazards analysis of TNX Large Melter-Off-Gas System  

Microsoft Academic Search

Analysis of the potential safety hazards and an evaluation of the engineered safety features and administrative controls indicate that the LMOG System can be operated without undue hazard to employees or the public, or damage to equipment. The safety features provided in the facility design coupled with the planned procedural and administrative controls make the occurrence of serious accidents very

1982-01-01

426

Refinery off gas treatment - why the fluidized bed option  

Microsoft Academic Search

Traditionally a CO-boiler is utilized at the tail end of a Fluidized Catalytic Cracking (FCC) process for reducing CO emissions and recuperating waste heat. During the feasibility study of the new Reduced Crude Conversion (RCC), the UOP licensed process, Ashland Petroleum Company recognized the requirement for SO emission control. Additional investigation indicated that a process including a fluidized bed of

I. F. Abdulally; B. R. Kersey

1986-01-01

427

Heat as a tracer to estimate dissolved organic carbon flux from a restored wetland  

USGS Publications Warehouse

Heat was used as a natural tracer to characterize shallow ground water flow beneath a complex wetland system. Hydrogeologic data were combined with measured vertical temperature profiles to constrain a series of two-dimensional, transient simulations of ground water flow and heat transport using the model code SUTRA (Voss 1990). The measured seasonal temperature signal reached depths of 2.7 m beneath the pond. Hydraulic conductivity was varied in each of the layers in the model in a systematic manual calibration of the two-dimensional model to obtain the best fit to the measured temperature and hydraulic head. Results of a series of representative best-fit simulations represent a range in hydraulic conductivity values that had the best agreement between simulated and observed temperatures and that resulted in simulated pond seepage values within 1 order of magnitude of pond seepage estimated from the water budget. Resulting estimates of ground water discharge to an adjacent agricultural drainage ditch were used to estimate potential dissolved organic carbon (DOC) loads resulting from the restored wetland. Estimated DOC loads ranged from 45 to 1340 g C/(m2 year), which is higher than estimated DOC loads from surface water. In spite of the complexity in characterizing ground water flow in peat soils, using heat as a tracer provided a constrained estimate of subsurface flow from the pond to the agricultural drainage ditch. Copyright ?? 2005 National Ground Water Association.

Burow, K. R.; Constantz, J.; Fujii, R.

2005-01-01

428

Heat as a tracer to estimate dissolved organic carbon flux from a restored wetland.  

PubMed

Heat was used as a natural tracer to characterize shallow ground water flow beneath a complex wetland system. Hydrogeologic data were combined with measured vertical temperature profiles to constrain a series of two-dimensional, transient simulations of ground water flow and heat transport using the model code SUTRA (Voss 1990). The measured seasonal temperature signal reached depths of 2.7 m beneath the pond. Hydraulic conductivity was varied in each of the layers in the model in a systematic manual calibration of the two-dimensional model to obtain the best fit to the measured temperature and hydraulic head. Results of a series of representative best-fit simulations represent a range in hydraulic conductivity values that had the best agreement between simulated and observed temperatures and that resulted in simulated pond seepage values within 1 order of magnitude of pond seepage estimated from the water budget. Resulting estimates of ground water discharge to an adjacent agricultural drainage ditch were used to estimate potential dissolved organic carbon (DOC) loads resulting from the restored wetland. Estimated DOC loads ranged from 45 to 1340 g C/(m2 year), which is higher than estimated DOC loads from surface water. In spite of the complexity in characterizing ground water flow in peat soils, using heat as a tracer provided a constrained estimate of subsurface flow from the pond to the agricultural drainage ditch. PMID:16029180

Burow, Karen R; Constantz, Jim; Fujii, Roger

429

Direct photolysis of carbonyl compounds dissolved in cloud and fog~droplets  

NASA Astrophysics Data System (ADS)

Gas-phase photolysis is an important tropospheric sink for many carbonyl compounds; however the significance of direct photolysis of these compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived effective Henry's law constants, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will (or will not) have competitive aqueous photolysis rates. We also present molecular dynamics simulations designed to estimate gas- and aqueous-phase extinction coefficients of unstudied atmospherically relevant compounds found in d-limonene and isoprene secondary organic aerosol. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water-soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only two out of the 92 carbonyl compounds investigated, pyruvic acid and acetoacetic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking ?,?-conjugation that were investigated, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected under typical atmospheric conditions.

Epstein, S. A.; Tapavicza, E.; Furche, F.; Nizkorodov, S. A.

2013-09-01

430

Investigating ebullition in a sand column using dissolved gas analysis and reactive transport modeling.  

PubMed

Ebullition of gas bubbles through saturated sediments can enhance the migration of gases through the subsurface, affect the rate of biogeochemical processes, and potentially enhance the emission of important greenhouse gases to the atmosphere. To better understand the parameters controlling ebullition, methanogenic conditions were produced in a column experiment and ebullition through the column was monitored and quantified through dissolved gas analysis and reactive transport modeling. Dissolved gas analysis showed rapid transport of CH4 vertically through the column at rates several times faster than the bromide tracer and the more soluble gas CO2, indicating that ebullition was the main transport mechanism for CH4. An empirically derived formulation describing ebullition was integrated into the reactive transport code MIN3P allowing this process to be investigated on the REV scale in a complex geochemical framework. The simulations provided insights into the parameters controlling ebullition and show that, over the duration of the experiment, 36% of the CH4 and 19% of the CO2 produced were transported to the top of the column through ebullition. PMID:16999111

Amos, Richard T; Mayer, K Ulrich

2006-09-01

431

Seasonal variability of total dissolved fluxes and origin of major dissolved elements within a large tropical river: The Orinoco, Venezuela  

NASA Astrophysics Data System (ADS)

Seasonal variations of total dissolved fluxes of the lower Orinoco River were calculated taking into account four complete hydrological cycles during a five-year period (2005-2010). The modern concentrations of total dissolved solids (TDS) of the Orinoco surface waters were compared with data collected during the second half of the last century published in the literature. This comparison leads to the conclusion that chemical composition did not evolve significantly at least over the last thirty to forty years. Surface waters of the Orinoco at Ciudad Bolivar are between bicarbonated calcic and bicarbonated mixed. In comparison to mean values of concentrations of total dissolved solids (TDS) of world river surface waters (89.2mgl?1), the Orinoco River at Ciudad Bolivar presents mainly low mineralized surface waters (2005-10: TDS 30mgl?1). The TDS fluxes passing at this station in direction to the Atlantic Ocean between 2005 and 2010 were estimated at 30נ106tyr?1, i.e. 36tkm?2yr?1. It was observed that the seasonal variations (dry season vs wet season) of total dissolved fluxes (TDS and dissolved organic carbon (DOC)) are mainly controlled by discharge variations. Two groups of elements have been defined from dilution curves and molar ratio diagrams. Ca2+, Mg2+, HCO3?, Cl? and Na+ mainly come from the same geographic and lithologic area, the Andes. K+ and SiO2 essentially come from the Llanos and the Guayana Shield. These findings are important for understanding fundamental geochemical processes within the Orinoco River basin, but also as a baseline study in the perspective of the development of numerous mining activities related with aluminum and steel industries; and the plans ofthe Venezuelan government to construct new fluvial ports on the lower Orinoco for the transport of hydrocarbons.

Laraque, Alain; Moquet, Jean-Sbastien; Alkattan, Rana; Steiger, Johannes; Mora, Abrahan; Adle, Georges; Castellanos, Bartolo; Lagane, Christle; Lopez, Jos Luis; Perez, Jesus; Rodriguez, Militza; Rosales, Judith

2013-07-01

432

Quantification of CH4 loss and transport in dissolved plumes of the Santa Barbara Channel, California  

NASA Astrophysics Data System (ADS)

Methane (CH4) emitted into the coastal ocean faces two primary fates: escape to the atmosphere or prolonged dissolution that allows sufficient time for oxidation by methanotrophic bacteria. The partitioning of CH4 between these fates is modulated by physical, chemical and biological factors, including the distribution of CH4 in the water, temperature, wind speed, water movement, and the biological CH4 oxidation rate. Because of the underlying complexity, studies rarely quantify all of these factors in unison, thereby leaving gaps in our understanding of CH4 biogeochemistry in the coastal ocean. In this study we estimated the partitioning of CH4 between transport, microbial oxidative loss, and sea-air transfer in a defined plume of dissolved CH4 originating from one of the world's largest seep fields, near Coal Oil Point (COP) in the Santa Barbara Channel, California. Depth distributions of CH4 concentration, biologically mediated oxidation rate, and current velocity were quantified at 12 stations in a 198 km2 area down-current from COP on July 4-5, 2007. Six stations were sampled again on July 7, 2007 to evaluate temporal plume variability. The observed CH4 distribution revealed two distinct CH4 plumes: a shallow plume centered at 40 m and a deeper plume centered at 200 m. The shallow plume originates at COP; the source of the deeper CH4 plume is not known. Cross-sections of both plumes were used to calculate transport and loss terms for dissolved CH4. The results indicate that the majority of the dissolved CH4 is advected and diffuses horizontally by turbulence whereas microbial oxidation, sea-air gas transfer, and vertical turbulent diffusion are less significant. Based on rates estimated in the study area, a model was developed to simulate the fate of the dissolved CH4. The model results suggest that 60% of the CH4 of the sampled plumes will ultimately be microbially oxidized and 40% will be transferred to the atmosphere by sea-air gas exchange under the sampling conditions. These results illustrate the significance of microbial CH4 oxidation in coastal oceans.

Mau, Susan; Heintz, Monica B.; Valentine, David L.

2012-01-01

433

Recycle Waste Collection Tank (RWCT) simulant testing in the PVTD feed preparation system  

SciTech Connect

(This is part of the radwaste vitrification program at Hanford.) RWCT was to routinely receive final canister decontamination sand blast frit and rinse water, Decontamination Waste Treatment Tank bottoms, and melter off-gas Submerged Bed Scrubber filter cake. In order to address the design needs of the RWCT system to meet performance levels, the PNL Vitrification Technology (PVTD) program used the Feed Preparation Test System (FPTS) to evaluate its equipment and performance for a simulant of RWCT slurry. (FPTS is an adaptation of the Defense Waste Processing Facility feed preparation system and represents the initially proposed Hanford Waste Vitrification Plant feed preparation system designed by Fluor-Daniel, Inc.) The following were determined: mixing performance, pump priming, pump performance, simulant flow characterization, evaporator and condenser performance, and ammonia dispersion. The RWCT test had two runs, one with and one without tank baffles.

Abrigo, G.P.; Daume, J.T.; Halstead, S.D.; Myers, R.L.; Beckette, M.R.; Freeman, C.J.; Hatchell, B.K.

1996-03-01

434

Azomethine H colorimetric method for determining dissolved boron in water  

USGS Publications Warehouse

An automated colorimetric method for determining dissolved boron in water is described. The boron is complexed with azomethine H, which is readily available as the condensation product of H acid (8-amino-1-naphthol-3,6-disulfonic acid) and salicylaldehyde. The absorbance of the yellow complex formed is then measured colorimetrically at 410 nm. Interference effects from other dissolved species are minimized by the addition of diethylenetriaminepentaacetic acid (DTPA); however, iron, zinc, and bicarbonate interfere at concentrations above 400 ??g/L, 2000 ??g/L, and 200 mg/L, respectively. The bicarbonate interference can be eliminated by careful acidification of the sample with concentrated HCl to a pH between 5 and 6. Thirty samples per hour can be routinely analyzed over the range of from 10 to 400 ??g/L, boron.

Spencer, R. R.; Erdmann, D. E.

1979-01-01

435

Isotope correlation verification of analytical measurements for dissolver materials  

SciTech Connect

An independent verification of analytical results for accountability measurements of dissolver materials can be performed using the Iosotop Correlation Technique (ICT). ICT is based on the relationships that exist between the initial and final elemental concentration and isotopic abundances of the nuclear fuel. Linear correlation functions between isotopic ratios and plutonium/uranium ratios have been developed for specific reactor fuels. The application of these correlations to already existing analytical data provides a laboratory additional confidence in the reported results. Confirmation is done by a test of consistancy with historical data. ICT is being utilized with dissolver accountability measurements at the Savannah River Plant Laboratory. The application, implementation, and operating experience of this technique are presented.

Satkowski, J. (E.I. du Pont de Nemours and Co., Savannah River Plant, Aiken, SC (US))

1988-01-01

436

Dissolved organic matter enhances transport of PAHs to aquatic organisms.  

PubMed

In this study, the uptake of pyrene and benzo[b]fluoranthene by an aquatic worm (Lumbriculus variegatus) and a poly(dimethylsiloxane) coated glass fiber was studied at different humic acid concentrations. The accumulation of pyrene was not affected by the presence of the humic matrix. However, the accumulation rate of benzo[b]fluoranthene increased a factor of 3 for the fiber and a factor of 4 when 55 mg L(-1) dissolved organic carbon was added in the form of humic acid. The difference between the two chemicals can be explained by the higher affinity of benzo[b]fluoranthene for the dissolved humic material. A comparison of modeled transport enhancement of benzo[b]fluoranthene by humic acid and the experimental results suggested that the benzo[b]fluoranthene complexed with the humic phase was not completely labile. PMID:19848124

Ter Laak, Thomas L; Ter Bekke, Martin A; Hermens, Joop L M

2009-10-01

437

Preparation of encapsulated proteins dissolved in low viscosity fluids.  

PubMed

The majority of proteins are too large to be comprehensively examined by solution NMR methods, primarily because they tumble too slowly in solution. One potential approach to making the NMR relaxation properties of large proteins amenable to modern solution NMR techniques is to encapsulate them in a reverse micelle which is dissolved in a low viscosity fluid. Unfortunately, promising low viscosity fluids such as the short chain alkanes, supercritical carbon dioxide, and various halocarbon refrigerants all require the application of significant pressure to be kept liquefied at room temperature. Here we describe the design and use of a simple cost effective NMR tube suitable for the preparation of solutions of proteins encapsulated in reverse micelles dissolved in such fluids. PMID:10382308

Ehrhardt, M R; Flynn, P F; Wand, A J

1999-05-01

438

Asymmetrical relationships between absorbance, fluorescence, and dissolved organic carbon  

SciTech Connect

Relationships between ultraviolet absorbance, fluorescence, and concentrations of dissolved organic carbon (DOC) were examined in four model materials fractionated by gel permeation chromatography. Fluorescence was consistently a poor predictor of DOC concentration, and absorbance correctly predicted DOC concentration only in the more labile materials. Asymmetry between DOC and the two optical parameters was related to the apparent molecular weight of the dissolved organic matter (DOM) and could be explained by greater levels of internal quenching and shielding in compounds of larger apparent molecular weight. A lake-to-lake comparison (n = 55) showed a calcium-related selective loss of high molecular weight humic materials, which invalidates the use of either optical characteristic as a good predictor of DOC concentration in hard-water systems. Calcium-related seasonal and between-lake differences in the relative molecular weight of the DOM may selectively alter trace metal availability.

Stewart, A.J.; Wetzl, R.G.

1981-01-01

439

Biodegradable Materials and Their Effect on Dissolved Oxygen Levels  

NSDL National Science Digital Library

In this laboratory exercise, students will design and conduct an experiment to evaluate the effect of the presence of biodegradable materials on dissolved oxygen levels. They will come to understand the effect of biodegradable pollutants on water quality, design and conduct an experiment, interpret data, suggest additional studies, and preform serial dilutions. The students will discover that in aquatic systems, aerobic microorganisms will consume biodegradable material for energy, and in doing so will also take up oxygen from the environment as part of the cellular respiration process. They will also learn that scientists use dissolved oxygen levels as an indication of contamination by such pollutants as sewage, agricultural runoff, and organic industrial effluents. This activity has an accompanying teacher site with hints and more information. There are also links to several related sites.

440

Temporal variations in dissolved selenium in Lake Kinneret (Israel)  

Microsoft Academic Search

: Selenium is an essential micronutrient for the growth of the dinoflagellate Peridinium gatunense that dominates the spring algal bloom in Lake Kinneret (LK). The relationship between the levels of dissolved selenium species\\u000a and the occurance of algal blooms in this lake was studied. During algal blooms of P. gatunense in spring and of the blue-green Aphanizomenon ovalisporum in fall

Ami Nishri; Itschak B. Brenner; Gwendy E. M. Hall; Howard E. Taylor

1999-01-01

441

Dissolved oxygen and thermal regimes of a Ugandan crater lake  

Microsoft Academic Search

This paper quantifies the temporal pattern of thermal stratification and deoxygenation in Lake Nkuruba, a small (3 ha), deep\\u000a (maximum depth = 38 m) crater lake in western Uganda. Dissolved oxygen penetrated to an average depth of 9 m and a maximum\\u000a depth of 15 m below which the lake was permanently anoxic over the 2 years of study. Although

Lauren J. Chapman; Colin A. Chapman; Thomas L. Crisman; Frank G. Nordlie

1998-01-01

442

Subtidal Variability of Dissolved Oxygen in Western Long Island Sound  

Microsoft Academic Search

A simple model of the subtidal budget of dissolved oxygen in estuaries is developed and applied to observations in western Long Island Sound. The goal is to analyze the causes of hypoxia and develop a predictive capability for its onset and duration by estimating mixing coefficients and comparing simple models of their temporal variability. A single-segment lower-layer box-model for western

P. S. Gay; J. O'Donnell

2008-01-01

443

Carbohydrates in phytoplankton and freshly produced dissolved organic matter  

Microsoft Academic Search

Four taxonomically-diverse, phytoplankton cultures (Phaeocystis sp., Emiliania huxleyi, Synechococcus bacillaris, Skeletonema costatum) were grown in batch culture for 14 days, and the particulate and high-molecular-weight dissolved components of the cultures were harvested by tangential-flow ultrafiltration for bulk and molecular-level carbohydrate analyses. Bulk carbohydrates and neutral aldoses accounted for an average of 37% and 20%, respectively, of the particulate organic carbon

Andrew Biersmith; Ronald Benner

1998-01-01

444

Oxidative dissolution of metacinnabar (?-HgS) by dissolved oxygen  

Microsoft Academic Search

The oxidative dissolution rate of metacinnabar by dissolved O2 was measured at pH ?5 in batch and column reactors. In the batch reactors, the dissolution rate varied from 3.15 (0.40) to 5.87 (0.39) 10?2 ?mol\\/m2\\/day (I=0.01 M, 23C) and increased with stirring speed, a characteristic normally associated with a transport-controlled reaction. However, theoretical calculations, a measured activation energy of

Mark O Barnett; Ralph R Turner; Philip C Singer

2001-01-01

445

Dissolved and particulate carbohydrates in contrasting marine sediments  

Microsoft Academic Search

Dissolved and particulate carbohydrates were examined in contrasting Chesapeake Bay (estuarine) and mid-Atlantic shelf\\/slope break (continental margin) sediments. Particulate carbohydrates (PCHOs) represented ?59% of the total sediment particulate organic carbon (POC), and PCHO remineralization appeared to be a similar fraction of total sediment carbon oxidation (or Cox). When these results are compared with results from other coastal sediments and a

D. J. BURDIGE; A Skoog; K. GARDNER

2000-01-01

446

Luminescent nanobeads for optical sensing and imaging of dissolved oxygen  

Microsoft Academic Search

A variety of luminescent oxygen nanosensors were prepared by addressable staining of poly(styrene-block-vinylpyrrolidone)\\u000a nanobeads with metalligand complexes whose luminescence is quenched by oxygen. They display optimal sensitivity in responding\\u000a to dissolved oxygen in concentrations from 0 to 100% air saturation. The nanobeads based on cyclometallated iridium(III) complexes\\u000a with coumarins are especially promising due to excellent brightnesses. The nanosensors respond virtually

Sergey M. Borisov; Ingo Klimant

2009-01-01

447

Predicting dissolved oxygen in the Chesapeake Bay: applications and implications  

Microsoft Academic Search

Eutrophic depletion of dissolved oxygen (DO) and its consequences for ecosystem dynamics have been a central theme of research,\\u000a assessment and management policies for several decades in the Chesapeake Bay. Ongoing forecast efforts predict the extent\\u000a of the summer hypoxic\\/anoxic area due to nutrient loads from the watershed. However, these models neither predict DO levels\\u000a nor address the intricate interactions

M. Bala Krishna Prasad; Wen Long; Xinsheng Zhang; Robert J. Wood; Raghu Murtugudde

448

Electrical conductivity and total dissolved solids in urine  

Microsoft Academic Search

The objective of this paper is to study the relevance of electrical conductivity (EC) and total dissolved solids (TDS) in\\u000a early morning and random samples of urine of urinary stone patients; 2,000 urine samples were studied. The two parameters\\u000a were correlated with the extent of various urinary concrements. The early morning urine (EMU) and random samples of the patients\\u000a who

Y. M. Fazil Marickar

2010-01-01

449

Predicting Dissolved Organic Matter Transport In the Neponset River Watershed  

NASA Astrophysics Data System (ADS)

The major source of dissolved organic matter (DOM) to coastal waters is often terrestrial dissolved organic matter originating in coastal watersheds and delivered to the ocean by rivers or streams. While studies of carbon cycling in large rivers dominate the literature, small rivers deliver the bulk of the freshwater to coastal waters (~60%). However, the variability of organic matter fluxes in small rivers requires high spatial and temporal resolution measurements to adequately represent the processes controlling distributions and fluxes. In this study, dissolved organic carbon (DOC) and chromophoric dissolved organic matter (CDOM) were measured monthly for two years at 15 sampling sites throughout a small, coastal, urban watershed (~300 km2), the Neponset River Watershed. CDOM and DOC variability was found to depend on land use type, discharge/precipitation, and growing degree days (temperature). In addition water flow estimated using the Soil Water Assessment Tool (SWAT) model was used to improve estimates based on instantaneous flow measurements. Wetland areas provided the most DOC to the river, and impervious surfaces led to increased variability. Using the combination of geographical information systems (GIS) land use data, seasonal temperatures, rainfall, and modeled flow, DOC concentrations and transport could be estimated throughout the watershed and over the seasonal cycle. Simple statistical models of DOM endmember behavior could explain 40-70% of the observed seasonal variability. Using these simple relationships, trends in total DOM loading behavior can be predicted under various scenarios of land use change and global warming. Overall, detailed measurements of DOM throughout the Neponset River Watershed yield new insights into the watershed processes that affect terrestrial DOM delivery to coastal oceans.

Chen, R. F.; Huang, W.; Wang, D.; Tian, Y. Q.

2009-12-01

450

Nicotine Fast Dissolving Films Made of Maltodextrins: A Feasibility Study  

Microsoft Academic Search

This work aimed to develop a fast-dissolving film made of low dextrose equivalent maltodextrins (MDX) containing nicotine\\u000a hydrogen tartrate salt (NHT). Particular attention was given to the selection of the suitable taste-masking agent (TMA) and\\u000a the characterisation of the ductility and flexibility under different mechanical stresses. MDX with two different dextrose\\u000a equivalents (DEs), namely DE 6 and DE 12, were

Francesco Cilurzo; Irma E. Cupone; Paola Minghetti; Susanna Buratti; Francesca Selmin; Chiara G. M. Gennari; Luisa Montanari

2010-01-01

451

Microfabirated Clark-type Sensor for Measuing Dissolved Oxygen  

Microsoft Academic Search

This paper presents a microfabricated Clark-type sensor which exactly can measure dissolved oxygen in the cell containing solution. We designed and fabricated a microfabricated Clark-type sensor for measuring the oxygen respiration level of few cells. The microfabricated Clark-type sensor is composed of 3-electrodes on a glass substrate, a FEP (Fluorinated ethylene propylene) oxygen-permeable membrane, and PDMS (Polydimethylsiloxane) reservoir for storing

Jong-hyeon Chang; Myungki Choi; J. J. Pak; Dong-Young Lee; Youngmi Kim Pak

2007-01-01

452

Phthalic acid esters in dissolved fractions of landfill leachates  

Microsoft Academic Search

The distribution of phthalic acid esters (PAEs) (including diisobutylphthalate (DIBP), di-n-butylphthalate (DnBP) and bis(2-ethyl)hexylphthalate (DEHP)) in dissolved organic matter (DOM) fractions of leachates from sanitary or bioreactor landfills was evaluated. The leachate DOM was fractionated into humic acid (HA), fulvic acid (FA) and hydrophilic (HyI) fractions. Measurements showed that the PAEs were bound mostly to the HA fraction in leachate,

Zhong Zheng; Pin-Jing He; Li-Ming Shao; Duu-Jong Lee

2007-01-01

453

Dissolved inorganic and organic selenium in the Orca Basin  

Microsoft Academic Search

The vertical distributions of Se (IV), Se (VI) and dissolved organic Se have been determined in the oxic and non-sulfide-bearing anoxic zones of the Orca Basin. In the oxic waters, the concentration of Se (IV) increases with depth gradually from 0.25 nmole\\/kg at the surface to a maximum of 0.46 nmole\\/kg at 750 m and then decreases with depth to

Kazufumi Takayanagi; George T. F. Wong

1985-01-01

454

Models for dynamically dissolving star clusters (Kruijssen, 2009)  

Microsoft Academic Search

Evolutionary models for dissolving star clusters, computed with SPACEv3.0 (also see http:\\/\\/www.astro.uu.nl\\/~kruijs). The SPACE star cluster models contain evolution data for clusters with seven different metallicities. The set of data provided here contains models for five different dissolution timescales, three sets of remnant kick velocities, and two King profile parameters. Models for a wider range of parameters and for other

J. M. D. Kruijssen

2009-01-01

455

Flocculation and Air Requirements for Dissolved Air Flotation  

Microsoft Academic Search

Bench-scale and pilot-plant studies were used to investigate the effects of flocculation time and floe size on the performance of dissolved air flotation and to determine air requirements for three different types of water supplies. The results show that long flocculation periods are not needed and suggest that floc particles of 10-30 ?m should be prepared for flotation. Two measures

James K. Edzwald; John P. Walsh; Gary S. Kaminski; Howard J. Dunn

1992-01-01

456

Biological uptake of dissolved silica in the Amazon river estuary.  

PubMed

Approximately 25 percent of the dissolved silica carried by the Amazon River is depleted through diatom production in the inner estuary. Annual production of opaline frustules is estimated to be 15 million tons. However, few diatoms accumulate in modern shelf sediments and chemical recycling appears to be slight. Instead, many frustules apparently are transported landward into the river system, where they deposit in dunes and layers on and within mud and sand bars. PMID:17789156

Milliman, J D; Boyle, E

1975-09-19

457

Fluorescent dissolved organic matter in marine sediment pore waters  

Microsoft Academic Search

Fluorescent dissolved organic matter (FDOM) in sediment pore waters from contrasting sites in the Chesapeake Bay and along the mid-Atlantic shelf\\/slope break was studied using three-dimensional fluorescence spectroscopy. Benthic fluxes of FDOM were also examined at the Chesapeake Bay sites. The major fluorescence peaks observed in these pore waters corresponded to those observed in the water column. These included peaks

David J. Burdige; Scott W. Kline; Wenhao Chen

2004-01-01

458

Correlating Cryptosporidium removal using dissolved air flotation in water treatment  

Microsoft Academic Search

Cryptosporidium parvum behaves similarly to other low density colloidal particles in water. Their physical removal requires destabilization and subsequent separation. Removal as high as 4.9 log-units has been reported for gravity sedimentation but the average removal tends to be less than 2 log-units. Dissolved air flotation (DAF) is a method of water treatment that has been used primarily for sludge

Kathy French; Rodney K Guest; Gordon R Finch; Charles N Haas

2000-01-01

459

Hydroxyl Radical Production from Irradiated Arctic Dissolved Organic Matter  

Microsoft Academic Search

The hydroxyl radical (OH) plays an important role in the environmental chemistry and biogeochemistry of surface waters. OH\\u000a acts as a strong oxidant within the irradiated water column, and affects the bioavailability, cycling, and mineralization\\u000a of dissolved organic matter (DOM), the speciation and redox state of important trace metals e.g., iron and copper, and the\\u000a fate of persistent organic pollutants

Amanda M. Grannas; Christopher B. Martin; Yu-Ping Chin; Matthew Platz

2006-01-01

460

Dynamics of dissolved organic nitrogen in subalpine Castle Lake, California  

Microsoft Academic Search

Dissolved organic nitrogen (DON) concentrations were measured in meso-oligotrophic Castle Lake, California during the ice-free season in 1982, 1983 and 1984. No consistent relationships were found between DON and particulate-N, primary productivity rates or chlorophyll concentrations. However, increases in DON concentrations were observed in the early growing season of 1982 and 1984 when water temperature was rising and a diatom

J. P. Zehr; S. G. Paulsen; R. P. Axler; C. R. Goldman

1988-01-01

461

Partitioning of dissolved chlorinated ethenes into vegetable oil  

Microsoft Academic Search

Food-grade soybean oil (SoyOil) has been used to enhance in situ anaerobic bioremediation at sites contaminated with chlorinated ethenes (CEs). The abiotic interactions of SoyOil with the CEs may be significant and need to be better understood. The oil: water partition coefficients (Kp) of dissolved CEs into SoyOil were measured in batch tests and ranged from 22 to 1200 with

Patricia Pfeiffer; Angela R. Bielefeldt; Tissa Illangasekare; Bruce Henry

2005-01-01

462

Spontaneous assembly of marine dissolved organic matter into polymer gels  

Microsoft Academic Search

A large pool of organic carbon resides in the world's oceans in the form of dissolved organic matter (DOM),. DOM is operationally defined as the fraction of organic matter that passes through a filter with a given pore size (which can range from less than 0.1mum to 0.46mum). This fraction has a longer oceanic residence time - and is generally

Wei-Chun Chin; Mnica V. Orellana; Pedro Verdugo

1998-01-01

463

Dissolved Nutrient Retention Dynamics in River Networks: A Modeling Investigation of Transient Flow and Scale Effects  

SciTech Connect

In this paper, we use a dynamic network flow model, coupled with a transient storage zone biogeochemical model, to simulate dissolved nutrient removal processes at the channel network scale. We have explored several scenarios in respect of the combination of rainfall variability, and the biological and geomorphic characteristics of the catchment, to understand the dominant controls on removal and delivery of dissolved nutrients (e.g., nitrate). These model-based theoretical analyses suggested that while nutrient removal efficiency is lower during flood events compared to during baseflow periods, flood events contribute significantly to bulk nutrient removal, whereas bulk removal during baseflow periods is less. This is due to the fact that nutrient supply is larger during flood events; this trend is even stronger in large rivers. However, the efficiency of removal during both periods decreases in larger rivers, however, due to (i) increasing flow velocities and thus decreasing residence time, and (ii) increasing flow depth, and thus decreasing nutrient uptake rates. Besides nutrient removal processes can be divided into two parts: in the main channel and in the hyporheic transient storage zone. When assessing their relative contributions the size of the transient storage zone is a dominant control, followed by uptake rates in the main channel and in the transient storage zone. Increasing size of the transient storage zone with downstream distance affects the relative contributions to nutrient removal of the water column and the transient storage zone, which also impacts the way nutrient removal rates scale with increasing size of rivers. Intra-annual hydrologic variability has a significant impact on removal rates at all scales: the more variable the streamflow is, compared to mean discharge, the less nutrient is removed in the channel network. A scale-independent first order uptake coefficient, ke, estimated from model simulations, is highly dependent on the relative size of the transient storage zone and how it changes in the downstream direction, as well as the nature of hydrologic variability.

Ye, Sheng; Covino, Timothy P.; Sivapalan, Murugesu; Basu, Nandita; Li, Hongyi; Wang, Shaowen

2012-06-30

464

Sequestration of Dissolved CO2 in the Oriskany Formation  

SciTech Connect

Experiments were conducted to determine the solubility of CO2 in a natural brine solution of the Oriskany formation under elevated temperature and pressure conditions. These data were collected at temperatures of 22 and 75 C and pressures between 100 and 450 bar. Experimentally determined data were compared with CO2 solubility predictions using a model developed by Duan and Sun (Chem. Geol. 2003, 193, 257-271). Model results compare well with Oriskany brine CO2 solubility data collected experimentally, suggesting that the Duan and Sun model is a reliable tool for estimating solution CO2 capacity in high salinity aquifers in the temperature and pressure range evaluated. The capacity for the Oriskany formation to sequester dissolved CO2 was calculated using results of the solubility models, estimation of the density of CO2 saturated brine, and available geographic information system (GIS) information on the formation depth and thickness. Results indicate that the Oriskany formation can hold approximately 0.36 gigatonnes of dissolved CO2 if the full basin is considered. When only the region where supercritical CO2 can exist (temperatures greater than 31 C and pressures greater than 74 bar) is considered, the capacity of the Oriskany formation to sequester dissolved CO2 is 0.31 gigatonnes. The capacity estimate considering the potential to sequester free-phase supercritical CO2 if brine were displaced from formation pore space is 8.8 gigatonnes in the Oriskany formation.

Dilmore, R.M.; Allen, D.E. (Salem State College, Salem, MA); McCarthy-Jones, J.R.; Hedges, S.W.; Soong, Yee

2008-04-15

465

Xe-129 NMR of xenon dissolved in biological media.  

NASA Astrophysics Data System (ADS)

The high solubility and large chemical shift of ^129Xe in various tissues makes it an ideal, non-invasive probe for pathological conditions such as cancer or atherosclerosis. To this end, we report NMR measurements of lineshapes, chemical shifts, and relaxation times of ^129Xe dissolved in the following biological tissues in vitro: heart, muscle, sinew, stomach(R.K. Mazitov, K. M. Enikeev, et al., Dokl. Akad. Nauk) 365, 396 (1999)., and the white and yolk of egg. NMR measurements of xenon dissolved in olive and sunflower oils are also reported. Tissues weighing 160--250 mg, not exposed to freezing, were studied in a 11.75 T field at the ^129Xe resonance frequency of 138.4 MHz; the pressure of xenon in the sealed-sample ampoules was ~20 bar. The influence of drugs and water content on tissues was