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Sample records for aqueous fluid-injection methods

  1. Downhole fluid injection systems, CO2 sequestration methods, and hydrocarbon material recovery methods

    DOEpatents

    Schaef, Herbert T.; McGrail, B. Peter

    2015-07-28

    Downhole fluid injection systems are provided that can include a first well extending into a geological formation, and a fluid injector assembly located within the well. The fluid injector assembly can be configured to inject a liquid CO2/H2O-emulsion into the surrounding geological formation. CO2 sequestration methods are provided that can include exposing a geological formation to a liquid CO2/H2O-emulsion to sequester at least a portion of the CO2 from the emulsion within the formation. Hydrocarbon material recovery methods are provided that can include exposing a liquid CO2/H2O-emulsion to a geological formation having the hydrocarbon material therein. The methods can include recovering at least a portion of the hydrocarbon material from the formation.

  2. Fluid injection and induced seismicity

    NASA Astrophysics Data System (ADS)

    Kendall, Michael; Verdon, James

    2016-04-01

    The link between fluid injection, or extraction, and induced seismicity has been observed in reservoirs for many decades. In fact spatial mapping of low magnitude events is routinely used to estimate a stimulated reservoir volume. However, the link between subsurface fluid injection and larger felt seismicity is less clear and has attracted recent interest with a dramatic increase in earthquakes associated with the disposal of oilfield waste fluids. In a few cases, hydraulic fracturing has also been linked to induced seismicity. Much can be learned from past case-studies of induced seismicity so that we can better understand the risks posed. Here we examine 12 case examples and consider in particular controls on maximum event size, lateral event distributions, and event depths. Our results suggest that injection volume is a better control on maximum magnitude than past, natural seismicity in a region. This might, however, simply reflect the lack of baseline monitoring and/or long-term seismic records in certain regions. To address this in the UK, the British Geological Survey is leading the deployment of monitoring arrays in prospective shale gas areas in Lancashire and Yorkshire. In most cases, seismicity is generally located in close vicinity to the injection site. However, in some cases, the nearest events are up to 5km from the injection point. This gives an indication of the minimum radius of influence of such fluid injection projects. The most distant events are never more than 20km from the injection point, perhaps implying a maximum radius of influence. Some events are located in the target reservoir, but most occur below the injection depth. In fact, most events lie in the crystalline basement underlying the sedimentary rocks. This suggests that induced seismicity may not pose a leakage risk for fluid migration back to the surface, as it does not impact caprock integrity. A useful application for microseismic data is to try and forecast induced seismicity

  3. Maximum magnitude earthquakes induced by fluid injection

    NASA Astrophysics Data System (ADS)

    McGarr, A.

    2014-02-01

    Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.

  4. Earthquakes induced by fluid injection and explosion

    USGS Publications Warehouse

    Healy, J.H.; Hamilton, R.M.; Raleigh, C.B.

    1970-01-01

    Earthquakes generated by fluid injection near Denver, Colorado, are compared with earthquakes triggered by nuclear explosion at the Nevada Test Site. Spatial distributions of the earthquakes in both cases are compatible with the hypothesis that variation of fluid pressure in preexisting fractures controls the time distribution of the seismic events in an "aftershock" sequence. We suggest that the fluid pressure changes may also control the distribution in time and space of natural aftershock sequences and of earthquakes that have been reported near large reservoirs. ?? 1970.

  5. Coping with earthquakes induced by fluid injection

    USGS Publications Warehouse

    McGarr, Arthur F.; Bekins, Barbara; Burkardt, Nina; Dewey, James W.; Earle, Paul; Ellsworth, William L.; Ge, Shemin; Hickman, Stephen H.; Holland, Austin F.; Majer, Ernest; Rubinstein, Justin L.; Sheehan, Anne

    2015-01-01

    Large areas of the United States long considered geologically stable with little or no detected seismicity have recently become seismically active. The increase in earthquake activity began in the mid-continent starting in 2001 (1) and has continued to rise. In 2014, the rate of occurrence of earthquakes with magnitudes (M) of 3 and greater in Oklahoma exceeded that in California (see the figure). This elevated activity includes larger earthquakes, several with M > 5, that have caused significant damage (2, 3). To a large extent, the increasing rate of earthquakes in the mid-continent is due to fluid-injection activities used in modern energy production (1, 4, 5). We explore potential avenues for mitigating effects of induced seismicity. Although the United States is our focus here, Canada, China, the UK, and others confront similar problems associated with oil and gas production, whereas quakes induced by geothermal activities affect Switzerland, Germany, and others.

  6. Method for processing aqueous wastes

    DOEpatents

    Pickett, John B.; Martin, Hollis L.; Langton, Christine A.; Harley, Willie W.

    1993-01-01

    A method for treating waste water such as that from an industrial processing facility comprising the separation of the waste water into a dilute waste stream and a concentrated waste stream. The concentrated waste stream is treated chemically to enhance precipitation and then allowed to separate into a sludge and a supernate. The supernate is skimmed or filtered from the sludge and blended with the dilute waste stream to form a second dilute waste stream. The sludge remaining is mixed with cementitious material, rinsed to dissolve soluble components, then pressed to remove excess water and dissolved solids before being allowed to cure. The dilute waste stream is also chemically treated to decompose carbonate complexes and metal ions and then mixed with cationic polymer to cause the precipitated solids to flocculate. Filtration of the flocculant removes sufficient solids to allow the waste water to be discharged to the surface of a stream. The filtered material is added to the sludge of the concentrated waste stream. The method is also applicable to the treatment and removal of soluble uranium from aqueous streams, such that the treated stream may be used as a potable water supply.

  7. Method for processing aqueous wastes

    DOEpatents

    Pickett, J.B.; Martin, H.L.; Langton, C.A.; Harley, W.W.

    1993-12-28

    A method is presented for treating waste water such as that from an industrial processing facility comprising the separation of the waste water into a dilute waste stream and a concentrated waste stream. The concentrated waste stream is treated chemically to enhance precipitation and then allowed to separate into a sludge and a supernate. The supernate is skimmed or filtered from the sludge and blended with the dilute waste stream to form a second dilute waste stream. The sludge remaining is mixed with cementitious material, rinsed to dissolve soluble components, then pressed to remove excess water and dissolved solids before being allowed to cure. The dilute waste stream is also chemically treated to decompose carbonate complexes and metal ions and then mixed with cationic polymer to cause the precipitated solids to flocculate. Filtration of the flocculant removes sufficient solids to allow the waste water to be discharged to the surface of a stream. The filtered material is added to the sludge of the concentrated waste stream. The method is also applicable to the treatment and removal of soluble uranium from aqueous streams, such that the treated stream may be used as a potable water supply. 4 figures.

  8. Method for processing aqueous wastes

    SciTech Connect

    Pickett, J.B.; Martin, H.L.; Langton, C.A.; Harley, W.W.

    1992-12-31

    This invention is comprised of a method for treating waste water such as that from an industrial processing facility comprising the separation of the waste water into a dilute waste stream and a concentrated waste stream. The concentrated waste stream is treated chemically to enhance precipitation and then allowed to separate into a sludge and a supernate. The supernate is skimmed or filtered from the sludge and blended with the dilute waste stream to form a second dilute waste stream. The sludge remaining is mixed with cementitious material, rinsed to dissolve soluble components, then pressed to remove excess water and dissolved solids before being allowed to cure. The dilute waste stream is also chemically treated to decompose carbonate complexes and metal ions and then mixed with cationic polymer to cause the precipitated solids to flocculate. Filtration of the flocculant removes sufficient solids to allow the waste water to be discharged to the surface of a stream. The filtered material is added to the sludge of the concentrated waste stream. The method is also applicable to the treatment and removal of soluble uranium from aqueous streams, such that the treated stream may be used as a potable water supply.

  9. Creating fluid injectivity in tar sands formations

    DOEpatents

    Stegemeier, George Leo; Beer, Gary Lee; Zhang, Etuan

    2010-06-08

    Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons are produced from the portion.

  10. Creating fluid injectivity in tar sands formations

    DOEpatents

    Stegemeier, George Leo; Beer, Gary Lee; Zhang, Etuan

    2012-06-05

    Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons including mobilized hydrocarbons are produced from the portion.

  11. Fluid injection and withdrawal in deep geothermal borehole.

    NASA Astrophysics Data System (ADS)

    Troiano, A.; Di Giuseppe, M. G.; Troise, C.; Tramelli, A.; De Natale, G.

    2012-04-01

    Geothermal systems represents a large resource that can provide, with a reasonable investment, a very high and cost-competitive power generating capacity. Considering also the very low environmental impact, their development represents, in the next decades, an enormous perspective. Despite this unquestionable potential, geothermal exploitation has always been perceived as limited, mainly because of the dependance of a site usefulness on several pre-existing conditions, mainly correlated to the reservoir rock's permeability and porosity, the amount of fluid saturation and, first of all, a convenient temperature-depth relationship. However, this major barrier it is not insurmountable and a notable progress in recent tests is achieved with the Enhanced Geothermal System (EGS), where massive fluid injection and withdrawal were performed to enlarge the natural fracture system of the basement rock. The permeability of the surrounding rocks results highly increased by pressurized fluids circulation and geothermal resources, in such way, become accessible in areas where deep reservoir exploitation, otherwise, could be not advantageous or even possible. Still problematic remains, however, most of the key technical requirements as, firstly, deep fluid injection, that represents a necessary field practice in EGS development. This kind of procedure have often strong and uncontrolled physical effects on the neighboring environment, involving possibly even large areas and, in particular, they represent one of the most important sources of seismicity induced by human activities. In some cases, seismicity reaches level that can not be sustained, as in the paradigmatic case of the 2006 M=3.4 earthquake induced in the Basel city (Swiss), with the consequent EGS project early termination. We test a numerical procedure that models deep fluid injection and withdrawal, during well stimulation, and its effects on induced seismicity. We propose such a procedure as a way to estimate how

  12. Method for aqueous phase reactions

    DOEpatents

    Elliott, Douglas C.; Hart, Todd R.

    2000-01-01

    A method for converting liquid organic material in a mixture into a product utilizing a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional metal deposited onto the support in a second dispersed phase. The additional metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase without substantially affecting the catalytic activity, thereby increasing the life time of the catalyst.

  13. Method for inhibiting corrosion in aqueous systems

    DOEpatents

    DeMonbrun, James R.; Schmitt, Charles R.; Schreyer, James M.

    1980-01-01

    This invention is a method for inhibiting corrosion in aqueous systems containing components composed of aluminum, copper, iron, or alloys thereof. The method comprises (a) incorporating in the aqueous medium 2-10 ppm by weight of tolyltriazole; an effective amount of a biodegradable organic biocide; 500-1000 ppm by weight of sodium metasilicate; 500-2000 ppm by weight of sodium nitrite; and 500-2000 ppm by weight of sodium tetraborate, all of these concentrations being based on the weight of water in the system; and (b) maintaining the pH of the resulting system in the range of 7.5 to 8.0. The method permits longterm operation with very low corrosion rates and bacteria counts. All of the additives to the system are biodegradable, permitting the treated aqueous medium to be discharged to the environment without violating current regulations. The method has special application to solar systems in which an aqueous medium is circulated through aluminum-alloy heat exchangers.

  14. Fluid injection triggering of 2011 earthquake sequence in Oklahoma

    NASA Astrophysics Data System (ADS)

    Keranen, K. M.; Savage, H. M.; Abers, G. A.; Cochran, E. S.

    2012-12-01

    Significant earthquakes are increasingly occurring within the United States midcontinent, with nine having moment-magnitude (Mw) ≥4.0 and five with Mw≥5.0 in 2011 alone. In parallel, wastewater injection into deep sedimentary formations has increased as unconventional oil and gas resources are developed. Injected fluids may lower normal stress on existing fault planes, and the correlation between injection wells and earthquake locations led to speculation that many 2011 earthquakes were triggered by injection. The largest earthquake potentially related to injection (Mw5.7) struck in November 2011 in central Oklahoma. Here we use aftershocks to document the fault patterns responsible for the M5.7 earthquake and a prolific sequence of related events, and use the timing and spatial correlation of the earthquakes with injection wells and subsurface structures to show that the earthquakes were likely triggered by fluid injection. The aftershock sequence details rupture along three distinct fault planes, the first of which reaches within 250 meters of active injection wells and within 1 km of the surface. This earthquake sequence began where fluids are injected at low pressure into a depleted oil reservoir bound by faults that effectively seal fluid flow. Injection into sealed compartments allows reservoir pressure to increase gradually over time, suggesting that reservoir volume, in this case, controls the triggering timescale. This process allows multi-year lags between the commencement of fluid injection and triggered earthquakes.

  15. Coupled discrete element modeling of fluid injection into dense granular media

    NASA Astrophysics Data System (ADS)

    Zhang, Fengshou; Damjanac, Branko; Huang, Haiying

    2013-06-01

    The coupled displacement process of fluid injection into a dense granular medium is investigated numerically using a discrete element method (DEM) code PFC2D® coupled with a pore network fluid flow scheme. How a dense granular medium behaves in response to fluid injection is a subject of fundamental and applied research interests to better understand subsurface processes such as fluid or gas migration and formation of intrusive features as well as engineering applications such as hydraulic fracturing and geological storage in unconsolidated formations. The numerical analysis is performed with DEM executing the mechanical calculation and the network model solving the Hagen-Poiseuille equation between the pore spaces enclosed by chains of particles and contacts. Hydromechanical coupling is realized by data exchanging at predetermined time steps. The numerical results show that increase in the injection rate and the invading fluid viscosity and decrease in the modulus and permeability of the medium result in fluid flow behaviors displaying a transition from infiltration-governed to infiltration-limited and the granular medium responses evolving from that of a rigid porous medium to localized failure leading to the development of preferential paths. The transition in the fluid flow and granular medium behaviors is governed by the ratio between the characteristic times associated with fluid injection and hydromechanical coupling. The peak pressures at large injection rates when fluid leakoff is limited compare well with those from the injection experiments in triaxial cells in the literature. The numerical analysis also reveals intriguing tip kinematics field for the growth of a fluid channel, which may shed light on the occurrence of the apical inverted-conical features in sandstone and magma intrusion in unconsolidated formations.

  16. Aqueous flooding methods for tertiary oil recovery

    SciTech Connect

    Peru, Deborah A.

    1989-01-01

    A method of aqueous flooding of subterranean oil bearing formation for tertiary oil recovery involves injecting through a well into the formation a low alkaline pH aqueous sodium bicarbonate flooding solution. The flooding solution's pH ranges from about 8.25 to 9.25 and comprises from 0.25 to 5 weight percent and preferably about 0.75 to 3.0 weight percent of sodium bicarbonate and includes a petroleum recovery surfactant of 0.05 to 1.0 weight percent and between 1 and 20 weight percent of sodium chloride. After flooding, an oil and water mixture is withdrawn from the well and the oil is separated from the oil and water mixture.

  17. Axisymmetric flows from fluid injection into a confined porous medium

    NASA Astrophysics Data System (ADS)

    Guo, Bo; Zheng, Zhong; Celia, Michael A.; Stone, Howard A.

    2016-02-01

    We study the axisymmetric flows generated from fluid injection into a horizontal confined porous medium that is originally saturated with another fluid of different density and viscosity. Neglecting the effects of surface tension and fluid mixing, we use the lubrication approximation to obtain a nonlinear advection-diffusion equation that describes the time evolution of the sharp fluid-fluid interface. The flow behaviors are controlled by two dimensionless groups: M, the viscosity ratio of displaced fluid relative to injected fluid, and Γ, which measures the relative importance of buoyancy and fluid injection. For this axisymmetric geometry, the similarity solution involving R2/T (where R is the dimensionless radial coordinate and T is the dimensionless time) is an exact solution to the nonlinear governing equation for all times. Four analytical expressions are identified as asymptotic approximations (two of which are new solutions): (i) injection-driven flow with the injected fluid being more viscous than the displaced fluid (Γ ≪ 1 and M < 1) where we identify a self-similar solution that indicates a parabolic interface shape; (ii) injection-driven flow with injected and displaced fluids of equal viscosity (Γ ≪ 1 and M = 1), where we find a self-similar solution that predicts a distinct parabolic interface shape; (iii) injection-driven flow with a less viscous injected fluid (Γ ≪ 1 and M > 1) for which there is a rarefaction wave solution, assuming that the Saffman-Taylor instability does not occur at the reservoir scale; and (iv) buoyancy-driven flow (Γ ≫ 1) for which there is a well-known self-similar solution corresponding to gravity currents in an unconfined porous medium [S. Lyle et al. "Axisymmetric gravity currents in a porous medium," J. Fluid Mech. 543, 293-302 (2005)]. The various axisymmetric flows are summarized in a Γ-M regime diagram with five distinct dynamic behaviors including the four asymptotic regimes and an intermediate regime

  18. Variable seismic response to fluid injection in central Oklahoma

    NASA Astrophysics Data System (ADS)

    Keranen, K. M.; Hogan, C.; Savage, H. M.; Abers, G. A.; van der Elst, N.

    2013-12-01

    Seismicity in Oklahoma since 2009 has been concentrated in the central portion of the state, in the areas of Jones, Prague, and Luther. These three regions account for ~75% of earthquakes in the 2009-2013 Oklahoma Geological Survey catalog. A swarm in the Jones region began in late 2008, with a maximum magnitude of 4.0, and activity continuing to the present. After relocation, the initially diffuse earthquakes in the Jones swarm delineate multiple subparallel faults. The Wilzetta fault zone ruptured in the Prague region in 2010 and again in 2011, with magnitudes up to Mw5.7, and the Luther region experienced two earthquakes of M4.4 and M4.2, with related aftershocks, in 2013. The earthquakes near Prague have previously been linked to wastewater disposal; here we show that the earthquakes near Jones and Luther may also be induced by deep disposal based on the upsurge in seismicity in central Oklahoma coupled with local relationships to pumping and reservoir structure. The timing of each sequence with respect to injection and the distribution of seismic activity differs, highlighting the variability in seismic response to fluid injection related to local permeability structure.

  19. An Analytical Model for Assessing Stability of Pre-Existing Faults in Caprock Caused by Fluid Injection and Extraction in a Reservoir

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Bai, Bing; Li, Xiaochun; Liu, Mingze; Wu, Haiqing; Hu, Shaobin

    2016-07-01

    Induced seismicity and fault reactivation associated with fluid injection and depletion were reported in hydrocarbon, geothermal, and waste fluid injection fields worldwide. Here, we establish an analytical model to assess fault reactivation surrounding a reservoir during fluid injection and extraction that considers the stress concentrations at the fault tips and the effects of fault length. In this model, induced stress analysis in a full-space under the plane strain condition is implemented based on Eshelby's theory of inclusions in terms of a homogeneous, isotropic, and poroelastic medium. The stress intensity factor concept in linear elastic fracture mechanics is adopted as an instability criterion for pre-existing faults in surrounding rocks. To characterize the fault reactivation caused by fluid injection and extraction, we define a new index, the "fault reactivation factor" η, which can be interpreted as an index of fault stability in response to fluid pressure changes per unit within a reservoir resulting from injection or extraction. The critical fluid pressure change within a reservoir is also determined by the superposition principle using the in situ stress surrounding a fault. Our parameter sensitivity analyses show that the fault reactivation tendency is strongly sensitive to fault location, fault length, fault dip angle, and Poisson's ratio of the surrounding rock. Our case study demonstrates that the proposed model focuses on the mechanical behavior of the whole fault, unlike the conventional methodologies. The proposed method can be applied to engineering cases related to injection and depletion within a reservoir owing to its efficient computational codes implementation.

  20. Method and apparatus for destroying organic contaminants in aqueous liquids

    DOEpatents

    Donaldson, Terrence L.; Wilson, James H.

    1993-01-01

    A method and apparatus for destroying organic contaminants, such as trichloroethylene, in aqueous liquids, such as groundwater, utilizing steam stripping integrated with biodegradation. The contaminated aqueous liquid is fed into a steam stripper causing the volatilization of essentially all of the organic contaminants and a portion of the aqueous liquid. The majority of the aqueous liquid is discharged from the steam stripper. The volatilized vapors are then condensed to the liquid phase and introduced into a bioreactor. The bioreactor contains methanotrophic microorganisms which convert the organic contaminants into mainly carbon dioxide. The effluent from the bioreactor is then recycled back to the steam stripper for further processing.

  1. Method and apparatus for destroying organic contaminants in aqueous liquids

    DOEpatents

    Donaldson, T.L.; Wilson, J.H.

    1993-09-21

    A method and apparatus for destroying organic contaminants, such as trichloroethylene, in aqueous liquids, such as groundwater, utilizing steam stripping integrated with biodegradation. The contaminated aqueous liquid is fed into a steam stripper causing the volatilization of essentially all of the organic contaminants and a portion of the aqueous liquid. The majority of the aqueous liquid is discharged from the steam stripper. The volatilized vapors are then condensed to the liquid phase and introduced into a bioreactor. The bioreactor contains methanotrophic microorganisms which convert the organic contaminants into mainly carbon dioxide. The effluent from the bioreactor is then recycled back to the steam stripper for further processing. 2 figures.

  2. Method for aqueous radioactive waste treatment

    DOEpatents

    Bray, L.A.; Burger, L.L.

    1994-03-29

    Plutonium, strontium, and cesium found in aqueous waste solutions resulting from nuclear fuel processing are removed by contacting the waste solutions with synthetic zeolite incorporating up to about 5 wt % titanium as sodium titanate in an ion exchange system. More than 99.9% of the plutonium, strontium, and cesium are removed from the waste solutions. 3 figures.

  3. Method for aqueous radioactive waste treatment

    DOEpatents

    Bray, Lane A.; Burger, Leland L.

    1994-01-01

    Plutonium, strontium, and cesium found in aqueous waste solutions resulting from nuclear fuel processing are removed by contacting the waste solutions with synthetic zeolite incorporating up to about 5 wt % titanium as sodium titanate in an ion exchange system. More than 99.9% of the plutonium, strontium, and cesium are removed from the waste solutions.

  4. Method for preparation of viscous aqueous liquids for wellbore injection

    SciTech Connect

    Abdo, M.K.

    1986-03-11

    This patent describes a method of preparing a viscous aqueous liquid for introduction into a well penetrating the earth. The method consists of: (a) incorporating a water-dispersible polysaccharide produced by addition of bacteria of the genus Xanthomonas on a carbohydrate into an aqueous liquid having a salinity within the range of 0-0.03 weight percent, (b) incorporating trivalent metal ions selected from the group consisting of aluminum, chromium, and iron ions into the aqueous liquid in a concentration sufficient to effect complexing of the polysaccharide, (c) subsequent to steps (a) and (b), adding an aqueous saline makeup solution to the aqueous liquid containing the polysaccharide and the trivalent metal ions to increase the salinity to a value of at least 0.5 weight percent, and (d) introducing the aqueous liquid into the well. Also described is the production of oil from a subterranean reservoir by the waterflooding technique in which an aqueous liquid comprising a polysaccharide produced by the action of bacteria of the genus Xanthomonas on a carbohydrate is introduced into a well penetrating the earth. The improvement consists of using an aqueous polysaccharide solution made by prehydrating the polysaccharide in fresh water and then mixing this prehydrated solution with hard water, whereby the prehydration step yields a polysaccharide solution in hard water of higher viscosity than by hydrating directly in hard water.

  5. INDUCED SEISMICITY. Seismicity triggered by fluid injection-induced aseismic slip.

    PubMed

    Guglielmi, Yves; Cappa, Frédéric; Avouac, Jean-Philippe; Henry, Pierre; Elsworth, Derek

    2015-06-12

    Anthropogenic fluid injections are known to induce earthquakes. The mechanisms involved are poorly understood, and our ability to assess the seismic hazard associated with geothermal energy or unconventional hydrocarbon production remains limited. We directly measure fault slip and seismicity induced by fluid injection into a natural fault. We observe highly dilatant and slow [~4 micrometers per second (μm/s)] aseismic slip associated with a 20-fold increase of permeability, which transitions to faster slip (~10 μm/s) associated with reduced dilatancy and micro-earthquakes. Most aseismic slip occurs within the fluid-pressurized zone and obeys a rate-strengthening friction law μ = 0.67 + 0.045ln(v/v₀) with v₀ = 0.1 μm/s. Fluid injection primarily triggers aseismic slip in this experiment, with micro-earthquakes being an indirect effect mediated by aseismic creep.

  6. INDUCED SEISMICITY. Seismicity triggered by fluid injection-induced aseismic slip.

    PubMed

    Guglielmi, Yves; Cappa, Frédéric; Avouac, Jean-Philippe; Henry, Pierre; Elsworth, Derek

    2015-06-12

    Anthropogenic fluid injections are known to induce earthquakes. The mechanisms involved are poorly understood, and our ability to assess the seismic hazard associated with geothermal energy or unconventional hydrocarbon production remains limited. We directly measure fault slip and seismicity induced by fluid injection into a natural fault. We observe highly dilatant and slow [~4 micrometers per second (μm/s)] aseismic slip associated with a 20-fold increase of permeability, which transitions to faster slip (~10 μm/s) associated with reduced dilatancy and micro-earthquakes. Most aseismic slip occurs within the fluid-pressurized zone and obeys a rate-strengthening friction law μ = 0.67 + 0.045ln(v/v₀) with v₀ = 0.1 μm/s. Fluid injection primarily triggers aseismic slip in this experiment, with micro-earthquakes being an indirect effect mediated by aseismic creep. PMID:26068845

  7. Method for removing organic liquids from aqueous solutions and mixtures

    DOEpatents

    Hrubesh, Lawrence W.; Coronado, Paul R.; Dow, Jerome P.

    2004-03-23

    A method for removing organic liquids from aqueous solutions and mixtures. The method employs any porous material preferably in granular form and having small pores and a large specific surface area, that is hydrophobic so that liquid water does not readily wet its surface. In this method, organics, especially organic solvents that mix with and are more volatile than water, are separated from aqueous solution by preferentially evaporating across the liquid/solid boundary formed at the surfaces of the hydrophobic porous materials. Also, organic solvents that are immiscible with water, preferentially wet the surfaces of the hydrophobic material and are drawn within the porous materials by capillary action.

  8. Enhanced remote earthquake triggering at fluid injection sites in the Midwestern U.S

    NASA Astrophysics Data System (ADS)

    van der Elst, N.; Savage, H. M.; Keranen, K. M.; Abers, G. A.

    2013-12-01

    A dramatic increase in seismicity in the Midwestern United States may be related to increased deep wastewater injection. We systematically examined sites of potential anthropogenic seismicity for evidence of remote earthquake triggering, which could indicate high fluid pressure and critically stressed faults. Using a cross-correlation method to enhance earthquake catalogs for individual TA stations, we found that regions of anthropogenic seismicity are also susceptible to earthquake triggering from natural transient stresses carried by seismic waves of large remote earthquakes. We detected triggered earthquakes following the three largest dynamic strain events since 2010, showing triggering by the 2010 Mw 8.8 Maule, Chile, earthquake at Prague, OK, and Trinidad, CO, and triggering by the 2011 Mw 9.1 Tohoku-Oki earthquake at Snyder, TX. Each of these sites hosted larger earthquakes (Mw 4.5-5.7) within the next 6 to 20 months. Enhanced triggering susceptibility could therefore be an advance indicator that fluid injection has brought the regional fault system to a critical state. Remote triggering is strongest at sites where the onset of seismicity lagged injection by many years, and where high swarm activity had not yet begun. The sites that triggered during the 2010 Chile earthquake did not trigger in the subsequent 2011 Tohoku earthquake, which suggests the importance of local conditions or a long recharge period for the triggering mechanism. By analogy with natural dynamic triggering at hydrothermal sites, we invoke a mechanism involving fracture unclogging or dynamic permeability enhancement, in which the seismic waves alter subsurface fluid flow and accelerate pressure changes on already critically stressed faults.

  9. Probability of a given-magnitude earthquake induced by a fluid injection

    NASA Astrophysics Data System (ADS)

    Shapiro, S. A.; Dinske, C.; Kummerow, J.

    2007-11-01

    Fluid injections in geothermic and hydrocarbon reservoirs induce small earthquakes (-3 < M < 2). Occasionally, however, earthquakes with larger magnitudes (M ~ 4) occur. We investigate magnitude distributions and show that for a constant injection pressure the probability to induce an earthquake with a magnitude larger than a given value increases with injection time corresponding to a bi-logarithmical law with a proportionality coefficient close to one. We find that the process of pressure diffusion in a poroelastic medium with randomly distributed sub-critical cracks obeying a Gutenberg-Richter relation well explains our observations. The magnitude distribution is mainly inherited from the statistics of pre-existing fracture systems. The number of earthquakes greater than a given magnitude also increases with the strength of the injection source and the tectonic activity of the injection site. Our formulation provides a way to estimate expected magnitudes of induced earthquakes. It can be used to avoid significant earthquakes by correspondingly planning fluid injections.

  10. Rupture propagation behavior and the largest possible earthquake induced by fluid injection into deep reservoirs

    NASA Astrophysics Data System (ADS)

    Gischig, Valentin S.

    2015-09-01

    Earthquakes caused by fluid injection into deep underground reservoirs constitute an increasingly recognized risk to populations and infrastructure. Quantitative assessment of induced seismic hazard, however, requires estimating the maximum possible magnitude earthquake that may be induced during fluid injection. Here I seek constraints on an upper limit for the largest possible earthquake using source-physics simulations that consider rate-and-state friction and hydromechanical interaction along a straight homogeneous fault. Depending on the orientation of the pressurized fault in the ambient stress field, different rupture behaviors can occur: (1) uncontrolled rupture-front propagation beyond the pressure front or (2) rupture-front propagation arresting at the pressure front. In the first case, fault properties determine the earthquake magnitude, and the upper magnitude limit may be similar to natural earthquakes. In the second case, the maximum magnitude can be controlled by carefully designing and monitoring injection and thus restricting the pressurized fault area.

  11. Seismic response to fluid injection at the Salton Sea geothermal field

    NASA Astrophysics Data System (ADS)

    Lajoie, L. J.; Brodsky, E. E.

    2012-12-01

    California hosts both the largest geothermal resource capacity and highest seismicity rate in the nation. With plans to increase geothermal output, and proven earthquake triggering in the vicinity of geothermal power plants worldwide, it is important to determine the local and regional effects of geothermal power production. This study examines the link between fluid injection and seismicity at the Salton Sea geothermal field in southern California by attempting to answer three motivating questions: 1) Does fluid injection at the geothermal field change local seismicity in a measurable way? 2) Are aftershocks triggered at the same rate inside and outside of the field? 3) How do the triggered aftershocks interact with regional fault networks, specifically, could these aftershocks trigger a societally significant event on the southern San Andreas fault? We use monthly fluid injection and production data from 1980 to 2012 for 88 wells at the Salton Sea geothermal field and seismic data for the same time span from the relocated Hauksson, Yang, and Shearer earthquake catalog for southern California to evaluate these issues. We find that seismicity is correlated in both time and space in the Salton Sea geothermal field to injection. The observations strongly suggest triggering in the field. We also find that earthquakes within the field trigger aftershocks at a higher rate than most earthquakes elsewhere in California. The combination of observations suggest that aftershocks from induced seismicity could extend beyond the edges of the field into the neighboring tectonic system.

  12. Velocity-dependent frictional behavior and slip magnitude of a fault affected by fluid injection activities

    NASA Astrophysics Data System (ADS)

    Urpi, L.; Rinaldi, A. P.; Spiers, C. J.

    2014-12-01

    Fluid injection is performed or planned for various activities, such as CO2 sequestration, gas storage, waste water disposal, and engineered geothermal system. Static stress and pressure perturbation due to the fluid injection may cause different scale earthquake phenomena, from instrumental recorded micro-seismicity to triggering of human-felt events. With this study we present a sensitivity analysis of the slip magnitude for the fluid injection in a reservoir-like structure. The reservoir, confined within impervious rock units, is composed by a porous rock mass laterally bounded by a fault. The fault is hydraulically connected to the fluid hosting unit. The numerical analysis is based on fully explicit sequential coupling between a multiphase fluid flow and a hydromechanical finite element calculation code. When the system conditions approaches failure, the simulation is performed in a fully dynamic mode. The coupling allows simulating change in permeability due to stress/strain change, as well as the slip on the fault due to overpressure and associated stress changes. Interface elements have been used to include the constitutive law characterizing the frictional behaviour of the fault. The change in friction with different slip velocities has been derived from laboratory results. Velocity- and strain-dependent frictional behavior of different patches of the fault influence the system evolution, resulting in larger or smaller slip length for the same injected volume.

  13. Physics based simulation of seismicity induced in the vicinity of a high-pressure fluid injection

    NASA Astrophysics Data System (ADS)

    McCloskey, J.; NicBhloscaidh, M.; Murphy, S.; O'Brien, G. S.; Bean, C. J.

    2013-12-01

    High-pressure fluid injection into subsurface is known, in some cases, to induce earthquakes in the surrounding volume. The increasing importance of ';fracking' as a potential source of hydrocarbons has made the seismic hazard from this effect an important issue the adjudication of planning applications and it is likely that poor understanding of the process will be used as justification of refusal of planning in Ireland and the UK. Here we attempt to understand some of the physical controls on the size and frequency of induced earthquakes using a physics-based simulation of the process and examine resulting earthquake catalogues The driver for seismicity in our simulations is identical to that used in the paper by Murphy et al. in this session. Fluid injection is simulated using pore fluid movement throughout a permeable layer from a high-pressure point source using a lattice Boltzmann scheme. Diffusivities and frictional parameters can be defined independently at individual nodes/cells allowing us to reproduce 3-D geological structures. Active faults in the model follow a fractal size distribution and exhibit characteristic event size, resulting in a power-law frequency-size distribution. The fluid injection is not hydraulically connected to the fault (i.e. fluid does not come into physical contact with the fault); however stress perturbations from the injection drive the seismicity model. The duration and pressure-time function of the fluid injection can be adjusted to model any given injection scenario and the rate of induced seismicity is controlled by the local structures and ambient stress field as well as by the stress perturbations resulting from the fluid injection. Results from the rate and state fault models of Murphy et al. are incorporated to include the effect of fault strengthening in seismically quite areas. Initial results show similarities with observed induced seismic catalogues. Seismicity is only induced where the active faults have not been

  14. Physics-based Probabilistic Seismic Hazard Analysis for Seismicity Induced by Fluid Injection

    NASA Astrophysics Data System (ADS)

    Foxall, W.; Hutchings, L. J.; Johnson, S.; Savy, J. B.

    2011-12-01

    Risk associated with induced seismicity (IS) is a significant factor in the design, permitting and operation of enhanced geothermal, geological CO2 sequestration and other fluid injection projects. Whereas conventional probabilistic seismic hazard and risk analysis (PSHA, PSRA) methods provide an overall framework, they require adaptation to address specific characteristics of induced earthquake occurrence and ground motion estimation, and the nature of the resulting risk. The first problem is to predict the earthquake frequency-magnitude distribution of induced events for PSHA required at the design and permitting stage before the start of injection, when an appropriate earthquake catalog clearly does not exist. Furthermore, observations and theory show that the occurrence of earthquakes induced by an evolving pore-pressure field is time-dependent, and hence does not conform to the assumption of Poissonian behavior in conventional PSHA. We present an approach to this problem based on generation of an induced seismicity catalog using numerical simulation of pressure-induced shear failure in a model of the geologic structure and stress regime in and surrounding the reservoir. The model is based on available measurements of site-specific in-situ properties as well as generic earthquake source parameters. We also discuss semi-empirical analysis to sequentially update hazard and risk estimates for input to management and mitigation strategies using earthquake data recorded during and after injection. The second important difference from conventional PSRA is that in addition to potentially damaging ground motions a significant risk associated with induce seismicity in general is the perceived nuisance caused in nearby communities by small, local felt earthquakes, which in general occur relatively frequently. Including these small, usually shallow earthquakes in the hazard analysis requires extending the ground motion frequency band considered to include the high

  15. Mechanical instability induced by water weakening in laboratory fluid injection tests

    NASA Astrophysics Data System (ADS)

    David, C.; Dautriat, J.; Sarout, J.; Delle Piane, C.; Menéndez, B.; Macault, R.; Bertauld, D.

    2015-06-01

    To assess water-weakening effects in reservoir rocks, previous experimental studies have focused on changes in the failure envelopes derived from mechanical tests conducted on rocks fully saturated either with water or with inert fluids. So far, little attention has been paid to the mechanical behavior during fluid injection under conditions similar to enhanced oil recovery operations. We studied the effect of fluid injection on the mechanical behavior of the weakly consolidated Sherwood sandstone in laboratory experiments. Our specimens were instrumented with 16 ultrasonic P wave transducers for both passive and active acoustic monitoring during loading and fluid injection to record the acoustic signature of fluid migration in the pore space and the development of damage. Calibration triaxial tests were conducted on three samples saturated with air, water, or oil. In a second series of experiments, water and inert oil were injected into samples critically loaded up to 80% or 70% of the dry or oil-saturated compressive strength, respectively, to assess the impact of fluid migration on mechanical strength and elastic properties. The fluids were injected with a low back pressure to minimize effective stress variations during injection. Our observations show that creep takes place with a much higher strain rate for water injection compared to oil injection. The most remarkable difference is that water injection in both dry and oil-saturated samples triggers mechanical instability (macroscopic failure) within half an hour whereas oil injection does not after several hours. The analysis of X-ray computed tomography images of postmortem samples revealed that the mechanical instability was probably linked to loss of cohesion in the water-invaded region.

  16. Porosity and Permeability Evolution Accompanying Hot fluid Injection into Diatomite, SUPRI TR-123

    SciTech Connect

    Diabira, I.; Castanier, L.M.; Kovscek, A.R.

    2001-04-19

    An experimental study of silica dissolution was performed to probe the evolution of permeability and porosity in siliceous diatomite during hot fluid injection such as water or steam flooding. Two competing mechanisms were identified. Silica solubility in water at elevated temperature causes rock dissolution thereby increasing permeability; however, the rock is mechanically weak leading to compressing of the solid matrix during injection. Permeability and porosity can decrease at the onset of fluid flow. A laboratory flow apparatus was designed and built to examine these processes in diatomite core samples.

  17. Automated Aqueous Sample Concentration Methods for in situ Astrobiological Instrumentation

    NASA Astrophysics Data System (ADS)

    Aubrey, A. D.; Grunthaner, F. J.

    2009-12-01

    The era of wet chemical experiments for in situ planetary science investigations is upon us, as evidenced by recent results from the surface of Mars by Phoenix’s microscopy, electrochemistry, and conductivity analyzer, MECA [1]. Studies suggest that traditional thermal volatilization methods for planetary science in situ investigations induce organic degradation during sample processing [2], an effect that is enhanced in the presence of oxidants [3]. Recent developments have trended towards adaptation of non-destructive aqueous extraction and analytical methods for future astrobiological instrumentation. Wet chemical extraction techniques under investigation include subcritical water extraction, SCWE [4], aqueous microwave assisted extraction, MAE, and organic solvent extraction [5]. Similarly, development of miniaturized analytical space flight instruments that require aqueous extracts include microfluidic capillary electrophoresis chips, μCE [6], liquid-chromatography mass-spectrometrometers, LC-MS [7], and life marker chips, LMC [8]. If organics are present on the surface of Mars, they are expected to be present at extremely low concentrations (parts-per-billion), orders of magnitude below the sensitivities of most flight instrument technologies. Therefore, it becomes necessary to develop and integrate concentration mechanisms for in situ sample processing before delivery to analytical flight instrumentation. We present preliminary results of automated solid-phase-extraction (SPE) sample purification and concentration methods for the treatment of highly saline aqueous soil extracts. These methods take advantage of the affinity of low molecular weight organic compounds with natural and synthetic scavenger materials. These interactions allow for the separation of target organic analytes from unfavorable background species (i.e. salts) during inline treatment, and a clever method for selective desorption is utilized to obtain concentrated solutions on the order

  18. Reticulation of Aqueous Polyurethane Systems Controlled by DSC Method

    PubMed Central

    Cakic, Suzana; Lacnjevac, Caslav; Rajkovic, Milos B.; Raskovic, Ljiljana; Stamenkovic, Jakov

    2006-01-01

    The DSC method has been employed to monitor the kinetics of reticulation of aqueous polyurethane systems without catalysts, and with the commercial catalyst of zirconium (CAT®XC-6212) and the highly selective manganese catalyst, the complex Mn(III)-diacetylacetonemaleinate (MAM). Among the polyol components, the acrylic emulsions were used for reticulation in this research, and as suitable reticulation agents the water emulsible aliphatic polyisocyanates based on hexamethylendoisocyanate with the different contents of NCO-groups were employed. On the basis of DSC analysis, applying the methods of Kissinger, Freeman-Carroll and Crane-Ellerstein the pseudo kinetic parameters of the reticulation reaction of aqueous systems were determined. The temperature of the examination ranged from 50°C to 450°C with the heat rate of 0.5°C/min. The reduction of the activation energy and the increase of the standard deviation indicate the catalytic action of the selective catalysts of zirconium and manganese. The impact of the catalysts on the reduction of the activation energy is the strongest when using the catalysts of manganese and applying all the three afore-said methods. The least aberrations among the stated methods in defining the kinetic parameters were obtained by using the manganese catalyst.

  19. Modeling the Fracturing of Rock by Fluid Injection - Comparison of Numerical and Experimental Results

    NASA Astrophysics Data System (ADS)

    Heinze, Thomas; Galvan, Boris; Miller, Stephen

    2013-04-01

    Fluid-rock interactions are mechanically fundamental to many earth processes, including fault zones and hydrothermal/volcanic systems, and to future green energy solutions such as enhanced geothermal systems and carbon capture and storage (CCS). Modeling these processes is challenging because of the strong coupling between rock fracture evolution and the consequent large changes in the hydraulic properties of the system. In this talk, we present results of a numerical model that includes poro-elastic plastic rheology (with hardening, softening, and damage), and coupled to a non-linear diffusion model for fluid pressure propagation and two-phase fluid flow. Our plane strain model is based on the poro- elastic plastic behavior of porous rock and is advanced with hardening, softening and damage using the Mohr- Coulomb failure criteria. The effective stress model of Biot (1944) is used for coupling the pore pressure and the rock behavior. Frictional hardening and cohesion softening are introduced following Vermeer and de Borst (1984) with the angle of internal friction and the cohesion as functions of the principal strain rates. The scalar damage coefficient is assumed to be a linear function of the hardening parameter. Fluid injection is modeled as a two phase mixture of water and air using the Richards equation. The theoretical model is solved using finite differences on a staggered grid. The model is benchmarked with experiments on the laboratory scale in which fluid is injected from below in a critically-stressed, dry sandstone (Stanchits et al. 2011). We simulate three experiments, a) the failure a dry specimen due to biaxial compressive loading, b) the propagation a of low pressure fluid front induced from the bottom in a critically stressed specimen, and c) the failure of a critically stressed specimen due to a high pressure fluid intrusion. Comparison of model results with the fluid injection experiments shows that the model captures most of the experimental

  20. Mechanical Weakening during Fluid Injection in Critically Stressed Sandstones with Acoustic Monitoring

    NASA Astrophysics Data System (ADS)

    David, C.; Dautriat, J. D.; Sarout, J.; Macault, R.; Bertauld, D.

    2014-12-01

    Water weakening is a well-known phenomenon which can lead to subsidence during the production of hydrocarbon reservoirs. The example of the Ekofisk oil field in the North Sea has been well documented for years. In order to assess water weakening effects in reservoir rocks, previous studies have focused on changes in the failure envelopes derived from mechanical tests conducted on rocks saturated either with water or with inert fluids. However, little attention has been paid so far on the mechanical behaviour during the fluid injection stage, like in enhanced oil recovery operations. We studied the effect of fluid injection on the mechanical behaviour of Sherwood sandstone, a weakly-consolidated sandstone sampled at Ladram Bay in UK. In order to highlight possible weakening effects, water and inert oil have been injected into critically-loaded samples to assess their effect on strength and elastic properties and to derive the acoustic signature of the saturation front for each fluid. The specimens were instrumented with 16 ultrasonic P-wave transducers for both passive and active acoustic monitoring during fluid injection and loading. After conducting standard triaxial tests on three samples saturated with air, water and oil respectively, mechanical creep tests were conducted on dry samples loaded at 80% of the compressive strength of the dry rock. While these conditions are kept constant, a fluid is injected at the bottom end of the sample with a low back pressure (0.5 MPa) to minimize effective stress variations during injection. Both water and oil were used as the injected pore fluid in two experiments. As soon as the fluids start to flow into the samples, creep is taking place with a much higher strain rate for water injection compared to oil injection. A transition from secondary creep to tertiary creep is observed in the water injection test whereas in the oil injection test no significant creep acceleration is observed after one pore volume of oil was

  1. Fluid injection induced seismicity reveals a NE dipping fault in the southeastern sector of the High Agri Valley (southern Italy)

    NASA Astrophysics Data System (ADS)

    Stabile, T. A.; Giocoli, A.; Perrone, A.; Piscitelli, S.; Lapenna, V.

    2014-08-01

    On 2 June 2006 the wastewater produced during the oil and gas field exploitation in High Agri Valley (southern Italy) started to be managed by disposal through pumping the fluids back into the subsurface at the Costa Molina 2 (CM2) injection well, located in the southeastern sector of the valley. The onset of microearthquakes (Ml ≤ 2) after 4 days at about 1.3 km SW of CM2 well suggests fluid injection induced seismicity by the diffusion of pore pressure. Moreover, the space-time evolution of 196 high-resolution relocated events reveals a previously unmapped NE dipping fault. We investigate the physical processes related to the fluid injection induced seismicity and delineate the previously unmapped fault by jointly analyzing seismicity data, geological observations, fluid injection data, the stratigraphic log of the CM2 well, and the electrical resistivity tomography survey carried out in the study area.

  2. Enhanced remote earthquake triggering at fluid-injection sites in the midwestern United States.

    PubMed

    van der Elst, Nicholas J; Savage, Heather M; Keranen, Katie M; Abers, Geoffrey A

    2013-07-12

    A recent dramatic increase in seismicity in the midwestern United States may be related to increases in deep wastewater injection. Here, we demonstrate that areas with suspected anthropogenic earthquakes are also more susceptible to earthquake-triggering from natural transient stresses generated by the seismic waves of large remote earthquakes. Enhanced triggering susceptibility suggests the presence of critically loaded faults and potentially high fluid pressures. Sensitivity to remote triggering is most clearly seen in sites with a long delay between the start of injection and the onset of seismicity and in regions that went on to host moderate magnitude earthquakes within 6 to 20 months. Triggering in induced seismic zones could therefore be an indicator that fluid injection has brought the fault system to a critical state. PMID:23846900

  3. Enhanced remote earthquake triggering at fluid-injection sites in the midwestern United States.

    PubMed

    van der Elst, Nicholas J; Savage, Heather M; Keranen, Katie M; Abers, Geoffrey A

    2013-07-12

    A recent dramatic increase in seismicity in the midwestern United States may be related to increases in deep wastewater injection. Here, we demonstrate that areas with suspected anthropogenic earthquakes are also more susceptible to earthquake-triggering from natural transient stresses generated by the seismic waves of large remote earthquakes. Enhanced triggering susceptibility suggests the presence of critically loaded faults and potentially high fluid pressures. Sensitivity to remote triggering is most clearly seen in sites with a long delay between the start of injection and the onset of seismicity and in regions that went on to host moderate magnitude earthquakes within 6 to 20 months. Triggering in induced seismic zones could therefore be an indicator that fluid injection has brought the fault system to a critical state.

  4. Workshop on induced Seismicity due to fluid injection/production from Energy-Related Applications

    SciTech Connect

    Majer, E.L.; Asanuma, Hiroshi; Rueter, Horst; Stump, Brian; Segall, Paul; Zoback, Mark; Nelson, Jim; Frohlich, Cliff; Rutledge, Jim; Gritto, Roland; Baria, Roy; Hickman, Steve; McGarr, Art; Ellsworth, Bill; Lockner, Dave; Oppenheimer, David; Henning, Peter; Rosca, Anca; Hornby, Brian; Wang, Herb; Beeler, Nick; Ghassemi, Ahmad; Walters, Mark; Robertson-Tait, Ann; Dracos, Peter; Fehler, Mike; Abou-Sayed, Ahmed; Ake, Jon; Vorobiev, Oleg; Julian, Bruce

    2011-04-01

    Geothermal energy, carbon sequestration, and enhanced oil and gas recovery have a clear role in U.S. energy policy, both in securing cost-effective energy and reducing atmospheric CO{sub 2} accumulations. Recent publicity surrounding induced seismicity at several geothermal and oil and gas sites points out the need to develop improved standards and practices to avoid issues that may unduly inhibit or stop the above technologies from fulfilling their full potential. It is critical that policy makers and the general community be assured that EGS, CO{sub 2} sequestration, enhanced oil/gas recovery, and other technologies relying on fluid injections, will be designed to reduce induced seismicity to an acceptable level, and be developed in a safe and cost-effective manner. Induced seismicity is not new - it has occurred as part of many different energy and industrial applications (reservoir impoundment, mining, oil recovery, construction, waste disposal, conventional geothermal). With proper study/research and engineering controls, induced seismicity should eventually allow safe and cost-effective implementation of any of these technologies. In addition, microseismicity is now being used as a remote sensing tool for understanding and measuring the success of injecting fluid into the subsurface in a variety of applications, including the enhancement of formation permeability through fracture creation/reactivation, tracking fluid migration and storage, and physics associated with stress redistribution. This potential problem was envisaged in 2004 following observed seismicity at several EGS sites, a study was implemented by DOE to produce a white paper and a protocol (Majer et al 2008) to help potential investors. Recently, however, there have been a significant number of adverse comments by the press regarding induced seismicity which could adversely affect the development of the energy sector in the USA. Therefore, in order to identify critical technology and research

  5. Seismic velocity changes associated with aseismic deformations of a fault stimulated by fluid injection

    NASA Astrophysics Data System (ADS)

    Rivet, Diane; De Barros, Louis; Guglielmi, Yves; Cappa, Frédéric; Castilla, Raymi; Henry, Pierre

    2016-09-01

    Fluid pressure plays an important role in the stability of tectonic faults. However, the in situ mechanical response of faults to fluid pressure variations is still poorly known. To address this question, we performed a fluid injection experiment in a fault zone in shales while monitoring fault movements at the injection source and seismic velocity variations from a near-distance (<10 m) monitoring network. We measured and located the P and S wave velocity perturbations in and around the fault using repetitive active sources. We observed that seismic velocity perturbations dramatically increase above 1.5 MPa of injection pressure. This is consistent with an increase of fluid flow associated with an aseismic dilatant shearing of the fault as shown by numerical modeling. We find that seismic velocity changes are sensitive to both fault opening by fluid invasion and effective stress variations and can be an efficient measurement for monitoring fluid-driven aseismic deformations of faults.

  6. The processes controlling damage zone propagation induced by wellbore fluid injection

    NASA Astrophysics Data System (ADS)

    Shalev, Eyal; Lyakhovsky, Vladimir

    2013-04-01

    Induced seismicity by wellbore fluid injection is an important tool for enhancing permeability in hydrocarbon and geothermal reservoirs. We model nucleation and propagation of damage zones and seismicity patterns for two-dimensional plane strain configuration at a depth of 5 km using novel numerical software developed in the course of this study. Simulations include the coupling of poro-elastic deformation and groundwater flow with damage evolution (weakening and healing) and its effect on the elastic and hydrologic parameters. Results show that the process occurring during fluid injection can be divided into four stages. The duration of each stage depends on the hydrological and mechanical parameters. Initially, fluid flows into the rock with no seismic events (5 to 20 hr). At this stage, damage increases from 0 to 1 creating two sets of conjugate zones (four narrow damage zones). Thereafter, the occurrence of seismic events and faulting begins and accelerates for the next 20 to 70 hr. At the initial part of this stage, two of the damage zones create stress shadows on the other two damage zones that stop progressing. The velocity of the advancing damage is limited only by the rock parameters controlling damage evolution. At the third stage, which lasts for the following 20-30 hr, damage acceleration decreases because fluid transport becomes a limiting factor as the damage zones are too long to efficiently transfer the pressure from the well to the tip of the damage zones. Finally, the damage decelerates and even stops in some cases. The propagation of damage is controlled and limited by fluid transport from the injection well to the tip of the damage zones because fluid transport does not keep up with the dilatancy of the damage zones. The time and distance of propagation depend on the damage-permeability coupling and the remote shear stress. Higher remote shear stress causes shorter initial periods of no seismicity; strong damage-permeability coupling causes

  7. Method of solidifying waste materials, such as radioactive or toxic materials, contained in aqueous solutions

    SciTech Connect

    Knieper, J.; May, K.; Printz, H.

    1984-07-24

    A method is disclosed of solidifying waste materials, such as radioactive or toxic materials, which are contained in aqueous solutions. To accomplish this solidification, an inorganic, non-metallic binding agent such as gypsum is intermixed with the aqueous solution and a substance such as pumice or ceramic tile which promotes the intermixing of the binding agent and the aqueous solution.

  8. Method of precipitating uranium from an aqueous solution and/or sediment

    SciTech Connect

    Tokunaga, Tetsu K; Kim, Yongman; Wan, Jiamin

    2013-08-20

    A method for precipitating uranium from an aqueous solution and/or sediment comprising uranium and/or vanadium is presented. The method includes precipitating uranium as a uranyl vanadate through mixing an aqueous solution and/or sediment comprising uranium and/or vanadium and a solution comprising a monovalent or divalent cation to form the corresponding cation uranyl vanadate precipitate. The method also provides a pathway for extraction of uranium and vanadium from an aqueous solution and/or sediment.

  9. Some Factors Controlling the Seismic Hazard due to Earthquakes Induced by Fluid Injection at Depth

    NASA Astrophysics Data System (ADS)

    McGarr, A.

    2012-12-01

    The maximum seismic moment (or moment magnitude) is an important measure of the seismic hazard associated with earthquakes induced by deep fluid injection. Although it would be advantageous to be able to predict the induced earthquake outcome, including the maximum seismic moment, of a specified fluid injection project in advance, this capability has, to date, proved to be elusive because the geomechanical and hydrological factors that control the seismic response to injection are too poorly understood. Fortunately, the vast majority of activities involving the injection of fluids into deep aquifers do not cause earthquakes that are large enough to be of any consequence. There have been, however, significant exceptions during the past 50 years, starting with the earthquakes induced by injection of wastewater at the Rocky Mountain Arsenal Well, during the 1960s, that caused extensive damage in the Denver, CO, area. Results from numerous case histories of earthquakes induced by injection activities, including wastewater disposal at depth and the development of enhanced geothermal systems, suggest that it may be feasible to estimate bounds on maximum magnitudes based on the volume of injected liquid. For these cases, volumes of injected liquid ranged from approximately 11.5 thousand to 5 million cubic meters and resulted in main shock moment magnitudes from 3.4 to 5.3. Because the maximum seismic moment appears to be linearly proportional to the total volume of injected fluid, this upper bound is expected to increase with time as long as a given injection well remains active. For example, in the Raton Basin, southern Colorado and northern New Mexico, natural gas is produced from an extensive coal bed methane field. The deep injection of wastewater associated with this gas production has induced a sequence of earthquakes starting in August 2001, shortly after the beginning of major injection activities. Most of this seismicity defines a northeast striking plane dipping

  10. Flow regime analysis for fluid injection into a confined aquifer: implications for CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Guo, B.; Zheng, Z.; Celia, M. A.; Stone, H.

    2015-12-01

    Carbon dioxide injection into a confined saline aquifer may be modeled as an axisymmetric two-phase flow problem. Assuming the two fluids segregate in the vertical direction due to strong buoyancy, and neglecting capillary pressure and miscibility, the lubrication approximation leads to a nonlinear advection-diffusion equation that describes the evolution of the sharp fluid-fluid interface. The flow behaviors in the system are controlled by two dimensionless groups: M, the viscosity ratio of the displaced fluid relative to injected fluid, and Γ , the gravity number, which represents the relative importance of buoyancy and fluid injection. Four different analytical solutions can be derived as the asymptotic approximations, representing specific values of the parameter pairs. The four solutions correspond to: (1) Γ << 1, M <1; (2) Γ << 1, M =1; (3) Γ << 1, M >1; and (4) Γ >> 1, any M values. The first two of these solutions are new, while the third corresponds to the solution of Nordbotten and Celia (2006) for confined injections and the fourth corresponds to the solution of (Lyle et al., 2005) for gravity currents in an unconfined aquifer. Overall, the various axisymmetric flows can be summarized in a Γ-M regime diagram with five distinct dynamic behaviors including the four asymptotic regimes and an intermediate regime (Fig. 1). Data from a number of CO2 injection sites around the world can be used to compute the two dimensionless groups Γ and M associated with each injection. When plotted on the regime diagram, these values show the flow behavior for each injection and how the values vary from site to site. For all the CO2 injections, M is always larger than 1, while Γ can range from 0.01 up to 100. The pairs of (Γ, M) with lower Γ values correspond to solution (3), while the ones with higher Γ values can move up to the intermediate regime and the flow regime for solution (4). The higher values of Γ correspond to pilot-scale injections with low

  11. Determination of hydraulic fracture parameters using a non-stationary fluid injection

    NASA Astrophysics Data System (ADS)

    Valov, A. V.; Golovin, S. V.

    2016-06-01

    In this paper, one provides a theoretical justification of the possibility of hydraulic fracture parameters determination by using a non-stationary fluid injection. It is assumed that the fluid is pumped into the fractured well with the time-periodic flow rate. It is shown that there is a phase shift between waves of fluid pressure and velocity. For the modelling purposes, the length and width of the fracture are assumed to be fixed. In the case of infinite fracture, one constructs an exact solution that ensures analytical determination of the phase shift in terms of the physical parameters of the problem. In the numerical calculation, the phase shift between pressure and velocity waves is found for a finite fracture. It is shown that the value of the phase shift depends on the physical parameters and on the fracture geometry. This makes it possible to determine parameters of hydraulic fracture, in particular its length, by the experimental measurement of the time shift and comparison with the numerical solution.

  12. Seismicity on Basement Faults Induced by Simultaneous Fluid Injection-Extraction

    NASA Astrophysics Data System (ADS)

    Chang, Kyung Won; Segall, Paul

    2016-08-01

    Large-scale carbon dioxide (CO2) injection into geological formations increases pore pressure, potentially inducing seismicity on critically stressed faults by reducing the effective normal stress. In addition, poroelastic expansion of the reservoir alters stresses, both within and around the formation, which may trigger earthquakes without direct pore-pressure diffusion. One possible solution to mitigate injection-induced earthquakes is to simultaneously extract pre-existing pore fluids from the target reservoir. To examine the feasibility of the injection-extraction strategy, we compute the spatiotemporal change in Coulomb stress on basement normal faults, including: (1) the change in poroelastic stresses Δ τ _s+fΔ σ _n, where Δ τ _s and Δ σ _n are changes in shear and normal stress. respectively, and (2) the change in pore-pressure fΔ p. Using the model of (J. Geophys. Res. Solid Earth 99(B2):2601-2618, 1994), we estimate the seismicity rate on basement fault zones. Fluid extraction reduces direct pore-pressure diffusion into conductive faults, generally reducing the risk of induced seismicity. Limited diffusion into/from sealing faults results in negligible pore pressure changes within them. However, fluid extraction can cause enhanced seismicity rates on deep normal faults near the injector as well as shallow normal faults near the producer by poroelastic stressing. Changes in seismicity rate driven by poroelastic response to fluid injection-extraction depends on fault geometry, well operations, and the background stressing rate.

  13. Significance for secure CO2 storage of earthquakes induced by fluid injection

    NASA Astrophysics Data System (ADS)

    Verdon, James P.

    2014-05-01

    The link between subsurface fluid injection and induced seismicity has gained recent significance with an increase in earthquakes associated with the disposal of oilfield waste fluids. There are obvious similarities between wastewater reinjection and proposed CO2 storage (CCS) operations. However, as well as the seismic hazard, induced seismicity during CCS operations poses additional risks, because an induced event located above the target reservoir could compromise the hydraulic integrity of the caprock. In this paper we re-examine case examples where earthquakes have been induced by wastewater injection into deep aquifers in the light of proposed future CCS operations. In particular we consider possible controls on event magnitudes, and look at the spatial distributions of events. We find that the majority of events are located below the target reservoirs. This is an encouraging observation from the perspective of caprock integrity, although it presents a challenge in terms of pre-injection characterization of deep-lying faults several kilometres below the target zone. We observe that 99% of events are found within 20 km of injection wells, suggesting a minimum radius for geomechanical characterization and monitoring. We conclude by making recommendations for modelling and monitoring strategies to be followed prior to and during commercial-scale deployment of CO2 storage projects.

  14. Measuring resistivity changes from within a first cased well to monitor fluids injected into oil bearing geological formations from a second cased well while passing electrical current between the two cased wells

    DOEpatents

    Vail, W.B. III.

    1993-02-16

    A.C. current is conducted through geological formations separating two cased wells in an oil field undergoing enhanced oil recovery operations such as water flooding operations. Methods and apparatus are disclosed to measure the current leakage conducted into a geological formation from within a first cased well that is responsive to fluids injected into formation from a second cased well during the enhanced oil production activities. The current leakage and apparent resistivity measured within the first cased well are responsive to fluids injected into formation from the second cased well provided the distance of separation between the two cased wells is less than, or on the order of, a Characteristic Length appropriate for the problem.

  15. Measuring resistivity changes from within a first cased well to monitor fluids injected into oil bearing geological formations from a second cased well while passing electrical current between the two cased wells

    DOEpatents

    Vail, III, William B.

    1993-01-01

    A.C. current is conducted through geological formations separating two cased wells in an oil field undergoing enhanced oil recovery operations such as water flooding operations. Methods and apparatus are disclosed to measure the current leakage conducted into a geological formation from within a first cased well that is responsive to fluids injected into formation from a second cased well during the enhanced oil production activities. The current leakage and apparent resistivity measured within the first cased well are responsive to fluids injected into formation from the second cased well provided the distance of separation between the two cased wells is less than, or on the order of, a Characteristic Length appropriate for the problem.

  16. THERMO-HYDRO-MECHANICAL MODELING OF WORKING FLUID INJECTION AND THERMAL ENERGY EXTRACTION IN EGS FRACTURES AND ROCK MATRIX

    SciTech Connect

    Robert Podgorney; Chuan Lu; Hai Huang

    2012-01-01

    Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing), to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid-heat system and our ability to reliably predict how reservoirs behave under stimulation and production. Reliable performance predictions of EGS reservoirs require accurate and robust modeling for strongly coupled thermal-hydrological-mechanical (THM) processes. Conventionally, these types of problems have been solved using operator-splitting methods, usually by coupling a subsurface flow and heat transport simulators with a solid mechanics simulator via input files. An alternative approach is to solve the system of nonlinear partial differential equations that govern multiphase fluid flow, heat transport, and rock mechanics simultaneously, using a fully coupled, fully implicit solution procedure, in which all solution variables (pressure, enthalpy, and rock displacement fields) are solved simultaneously. This paper describes numerical simulations used to investigate the poro- and thermal- elastic effects of working fluid injection and thermal energy extraction on the properties of the fractures and rock matrix of a hypothetical EGS reservoir, using a novel simulation software FALCON (Podgorney et al., 2011), a finite element based simulator solving fully coupled multiphase fluid flow, heat transport, rock deformation, and fracturing using a global implicit approach. Investigations are also conducted on how these poro- and thermal-elastic effects are related to fracture permeability

  17. Seismogenic response to fluid injection operations in Oklahoma and California: Implications for crustal stresses

    NASA Astrophysics Data System (ADS)

    Goebel, T.; Aminzadeh, F.

    2015-12-01

    The seismogenic response to induced pressure changes provides insight into the proximity to failure of faults close to injection sites. Here, we examine possible seismicity rate changes in response to wastewater disposal and enhanced oil recovery operations in hydrocarbon basins in California and Oklahoma. We test whether a statistically significant rate increase exists within these areas and determine the corresponding timing and location based on nonparametric modeling of background seismicity rates. Annual injection volumes increased monotonically since ~2001 in California and ~1998 in Oklahoma. While OK experienced a recent surge in seismic activity which exceeded the 95% confidence limit of a stationary Poisson process in ~2010, seismicity in CA showed no increase in background rates between 1980 and 2014. A systematic analysis of frequency-magnitude-distributions (FMDs) of likely induced earthquakes in OK indicates that FMDs are depleted in large-magnitude events. Seismicity in CA hydrocarbon basins, on the other hand, shows Gutenberg-Richter type FMDs and b~1. Moreover, the earthquakes and injection operations occur preferably in distinct areas in CA whereas in OK earthquakes occur closer to injection wells than expected from a random uniform process. To test whether injection operations may be responsible for the strongly different seismicity characteristics in CA and OK, we compare overall well density, wellhead pressures, peak and cumulative rates as well as injection depths. We find that average injection rates, pressures and volumes are comparable between CA and OK and that injection occurs on average 0.5 km deeper in CA than in OK. Thus, the here tested operational parameters can not easily explain the vastly different seismogenic response to injection operations in CA and OK, and may only be of secondary importance for the resulting earthquake activity. The potential to induce earthquakes by fluid injection operations is likely controlled by the

  18. Stabilized aqueous foam systems and concentrate and method for making them

    DOEpatents

    Rand, Peter B.

    1984-01-01

    This invention comprises a combination of a water soluble polymer of the polyacrylic acid type, a foam stabilizer of dodecyl alcohol, a surfactant, a solvent and water as a concentrate for use in producing stabilized aqueous foams. In another aspect, the invention comprises a solution of the concentrate with water. In still another aspect the invention includes a method of generating stabilized aqueous foams.

  19. Was the Timpson, Texas, M4.8 event induced by fluid injection?

    NASA Astrophysics Data System (ADS)

    Fan, Z.; Eichhubl, P.; Gale, J.; Olson, J. E.; Frohlich, C.; Gono, V.

    2014-12-01

    A M4.8 earthquake with dominant strike-slip near Timpson, east Texas, the largest documented earthquake to date in that region, has received extensive attention due to the possible linkage to waste water injection. The reliably located aftershocks align along a previously mapped fault striking about N42°W. Two active injection wells are located within 3 km of the aftershocks. One injection well became operational in August 2006 with an average injection rate of 42,750 m3/mo at an average pumping pressure of 12.4 MPa at depths between 1853 and 1868 m. Six months later, the second well started injection at 15,600 m3/mo. To investigate the causative relationship between fluid injection and possibly induced seismic fault slip, we integrated geologic and geophysical data into a poroelastic finite element model to simulate the spatial and temporal evolution of pore pressure and stress fields and analyze the stability of fault by applying the Coulomb failure criterion. Parametric studies were performed to analyze the sensitivity of Coulomb failure stress to the variability of input parameters including permeability of injection layer, fault orientation and permeability, and orientation and magnitude of stress state prior to injection. Assuming a Byerlee friction coefficient of 0.6, and using best available estimates of layer permeability, fault orientation, and stress tensor orientation and magnitude, we calculated fault slip occurs 55 months after the start of injection in the model, close to the observed delay of 69 months between injection and the M4.8 event. However, even with principal stress directions and fault orientation being reasonably well constrained, Coulomb failure stress is highly sensitive to input parameters resulting in large uncertainties in correlating injection rate and volume with the onset of induced seismic events. In addition, injection layer and fault zone permeability has a profound effect on the pore pressure evolution. These results

  20. Analysis of Scaling Parameters of Event Magnitudes by Fluid Injections in Reservoirs

    NASA Astrophysics Data System (ADS)

    Dinske, Carsten; Krüger, Oliver; Shapiro, Serge

    2014-05-01

    unaffected by the size of perturbed rock volume. Using both seismogenic index model and specific magnitude model we predict magnitude frequencies for different scenarios and compare them to observed data. We conclude that the seismogenic index model provides proper results which confirms its applicability as a predictive tool and, thus, it is valuable for assessment as well as mitigation of seismic hazard by fluid injections.

  1. Hydrological and chemical monitoring during Fluid Injection Test in Taiwan Chelungpu-fault Drilling Project

    NASA Astrophysics Data System (ADS)

    Murakami, M.; Tanaka, H.; Kuo, T.; Tsao, C.; Giletycz, S.; Chen, W.; Wang, C.; Chen, C.; Yang, T.; Ma, K.

    2007-12-01

    Taiwan Chelungpu-fault Drilling Project drilled two research boreholes (Hole A and B; approximately 40 m of their distance) through the Chelungpu Fault in Da-Keng, which ruptured in the 1999 Mw 7.6 Chi-Chi earthquake, in 2004. A branched borehole was drilled from Hole B in 2005 (Hole C), and then both Hole A and Hole C were perforated at the depth of the fault zone. The depth of perforation is 1111 m in Hole A and 1137 m in Hole C. Between the two boreholes, Fluid Injection Test (FIT) was performed on from November 2006 to March 2007 to estimate permeability and to understand hydrological and chemical properties along Chelungpu fault. Water was injected four times from Hole C at constant pressure during this FIT (4 MPa on November 2006 and January 2007, 3 and 5 MPa on March 2007). The arrival of injected water was monitored by seismometers, manometers, a Quadrupole Mass Spectrometry and chemical sensors at Hole A. In this present, we will report the results of water quality, gas and water pressure monitoring at Hole A. During FIT, tap water was used for injected water, which was characterized by high Oxidation Reduction Potential (ORP; 250 mV) and high Dissolved Oxygen (DO; 5.6 mg/L). Because both ORP and DO of the well water at Hole A kept low (ORP; -350 - -150, DO; <0.5 mg/L) before FIT, the arrival of injected water can be found by rise of these values. 1st FIT was performed for approximately 100 hours from 22:00 on 7th to 8:30 on 12th November. As a result, the values of ORP and DO increased on 10th November, which is 3 days after the start of 1st FIT. Then, the flow rate at Hole A suddenly increased 7 days after the first chemical reaction on 10th, that is, 10 days after the start of 1st FIT. This suggests that the permeability is 10-16 m2 assuming that the width of a permeable zone is 1 m by the preliminary estimation of the permeability based on the model of Kitagawa et al. (2002).

  2. In Situ Decommissioning Sensor Network, Meso-Scale Test Bed - Phase 3 Fluid Injection Test Summary Report

    SciTech Connect

    Serrato, M. G.

    2013-09-27

    located at the Florida International University Applied Research Center, Miami, FL (FIU-ARC). A follow-on fluid injection test was developed to detect fluid and ion migration in a cementitious material/grouted test cube using a limited number of existing embedded sensor systems. This In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) - Phase 3 Fluid Injection Test Summary Report summarizes the test implementation, acquired and processed data, and results from the activated embedded sensor systems used during the fluid injection test. The ISDSN-MSTB Phase 3 Fluid Injection Test was conducted from August 27 through September 6, 2013 at the FIU-ARC ISDSN-MSTB test cube. The fluid injection test activated a portion of the existing embedded sensor systems in the ISDSN-MSTB test cube: Electrical Resistivity Tomography-Thermocouple Sensor Arrays, Advance Tensiometer Sensors, and Fiber Loop Ringdown Optical Sensors. These embedded sensor systems were activated 15 months after initial placement. All sensor systems were remotely operated and data acquisition was completed through the established Sensor Remote Access System (SRAS) hosted on the DOE D&D Knowledge Management Information Tool (D&D DKM-IT) server. The ISDN Phase 3 Fluid Injection Test successfully demonstrated the feasibility of embedding sensor systems to assess moisture-fluid flow and resulting transport potential for contaminate mobility through a cementitious material/grout monolith. The ISDSN embedded sensor systems activated for the fluid injection test highlighted the robustness of the sensor systems and the importance of configuring systems in-depth (i.e., complementary sensors and measurements) to alleviate data acquisition gaps.

  3. Method for aqueous processing of ALN and compositions therefrom

    SciTech Connect

    Howard, K.H.

    1993-08-10

    An aqueous composition is described containing aluminum nitride powder which exhibits a reduced tendency for hydrolysis of the aluminum nitride contained therein, comprising: (a) a liquid medium containing water, (b) aluminum nitride powder, and (c) a combination of buffering agents including a weak acid and a conjugate base of the weak acid which controls the pH of water from about 5.5 to no greater than 7.0, the combination of buffering agents being employed at a lower weight percent concentration than the of the aluminum nitride powder and the buffering agents and the liquid medium forming a solution in the aqueous composition. 11. An aqueous composition containing aluminum nitride powder which exhibits a reduced tendency for hydrolysis of the aluminum nitride contained therein, comprising: (a) water, (b) aluminum nitride powder, and (c) a combination of buffering agents including a weak acid and a conjugate base of the weak acid, the combination of buffering agents being employed at a lower weight percent concentration than that of the aluminum nitride powder, the buffering agents and the water forming a solution in the aqueous composition the combination of buffering agents including a monobasic phosphate and a dibasic phosphate, the monobasic phosphate being selected from the group consisting of monobasic potassium phosphate, monobasic sodium phosphate, and monobasic ammonium phosphate and being employed at a concentration from about 0.01 to about 2 molarity in the water, the dibasic phosphate being selected from the group consisting of dibasic potassium phosphate, dibasic sodium phosphate, a dibasic ammonium phosphate and being employed at a concentration from about 0.003 to about 0.7 molarity in the water.

  4. Method of making particles from an aqueous sol

    DOEpatents

    Rankin, G.W.; Hooker, J.R.

    1973-07-24

    A process for preparing gel particles from an aqueous sol by forming the sol into droplets in a liquid system wherein the liquid phase contains a liquid organic solvent and a barrier agent. The barrier agent prevents dehydration from occurring too rapidly and permits surface tension effects to form sol droplets into the desired spheroidal shape. A preferred barrier agent is mineral oil. (Official Gazette)

  5. Induced Seismicity Associated with Waste Fluid Injection into Deep Wells in Youngstown, Ohio

    NASA Astrophysics Data System (ADS)

    Kim, W.

    2012-12-01

    Since March 2011, residents in Youngstown, Ohio area experienced small earthquakes (M ~2.5). By 25 November 2011, about a dozen small but felt earthquakes have occurred around Youngstown. On 1 Dec. 2011 four portable seismographs were deployed around the epicentral area to monitor seismicity at close distances and determine hypocenters of the small earthquakes accurately, because these shocks were occurring close to a deep waste fluid injection well that began injection operation on 28 Dec. 2010. On 24 December 2011, a magnitude 2.7 shock occurred in the epicentral area which was accurately located by using the portable station data. The 24 Dec. shock is located about 800 m from the injection well and at a depth of 3.5 km, suggesting that those earthquakes in Youngstown could have been induced by the deep well injection operation. Hence, the injection was stopped on 30 Dec. 2011. However, the largest earthquake in the sequence (M4.0) occurred on 31 December 2011 within about 24 hours from halting injection operation. A total of 196 shocks are recorded during Dec. 2011 - April 2012. These shocks occurred as three distinct clusters of events, and a swarm of 82 small events. Three clusters of shocks have occurred in the narrow depth range (3.5-3.9 km) and the clusters appear to be on parallel faults of similar orientation offset by about 200-300 m apart. The swarm of small shocks (M -0.3 - 0.1) have occurred on 18 Feb. 2012 and lasted only few hours (12:36-15:46). These swarm events all lie in a very small region with depth range 3.8-4.2 km. The Precambrian basement rock in the region is at a depth 2.7 km, and hence all the shocks have occurred within in the Precambrian basement. Focal mechanism of the main shock is predominantly strike-slip faulting along steeply dipping nodal planes. The orientation of the WSW striking nodal plane (265 degree) is consistent with the lineation of the main cluster of shocks that include well-located main shock and other two largest

  6. Elastic stress transfer as a diffusive process due to aseismic fault slip in response to fluid injection

    NASA Astrophysics Data System (ADS)

    Viesca, R. C.

    2015-12-01

    Subsurface fluid injection is often followed by observations of an enlarging cloud of microseismicity. The cloud's diffusive growth is thought to be a direct response to the diffusion of elevated pore fluid pressure reaching pre-stressed faults, triggering small instabilities; the observed high rates of this growth are interpreted to reflect a relatively high permeability of a fractured subsurface [e.g., Shapiro, GJI 1997]. We investigate an alternative mechanism for growing a microseismic cloud: the elastic transfer of stress due to slow, aseismic slip on a subset of the pre-existing faults in this damaged subsurface. We show that the growth of the slipping region of the fault may be self-similar in a diffusive manner. While this slip is driven by fluid injection, we show that, for critically stressed faults, the apparent diffusion of this slow slip may quickly exceed the poroelastically driven diffusion of the elevated pore fluid pressure. Under these conditions, microseismicity can be first triggered by the off-fault stress perturbation due to the expanding region of slip on principal faults. This provides an alternative interpretation of diffusive growth rates in terms of the subsurface stress state rather than an enhanced hydraulic diffusivity. That such aseismic slip may occur, outpace fluid diffusion, and in turn trigger microseismic events, is also suggested by on- and near-fault observations in past and recently reported fluid injection experiments [e.g., Cornet et al., PAGEOPH 1997; Guglielmi et al., Science 2015]. The model of injection-induced slip assumes elastic off-fault behavior and a fault strength determined by the product of a constant friction coefficient and the local effective normal stress. The sliding region is enlarged by the pore pressure increase resolved on the fault plane. Remarkably, the rate of self-similar expansion may be determined by a single parameter reflecting both the initial stress state and the magnitude of the pore pressure

  7. Aqueous based reflux method for green synthesis of nanostructures: Application in CZTS synthesis.

    PubMed

    Aditha, Sai Kiran; Kurdekar, Aditya Dileep; Chunduri, L A Avinash; Patnaik, Sandeep; Kamisetti, Venkataramaniah

    2016-01-01

    The aqueous based reflux method useful for the green synthesis of nanostructures is described in detail. In this method, the parameters: the order of addition of precursors, the time of the reflux and the cooling rate should be optimized in order to obtain the desired phase and morphology of the nanostructures. The application of this method is discussed with reference to the synthesis of CZTS nanoparticles which have great potential as an absorber material in the photovoltaic devices. The highlights of this method are:•Simple.•Low cost.•Aqueous based.

  8. Aqueous based reflux method for green synthesis of nanostructures: Application in CZTS synthesis.

    PubMed

    Aditha, Sai Kiran; Kurdekar, Aditya Dileep; Chunduri, L A Avinash; Patnaik, Sandeep; Kamisetti, Venkataramaniah

    2016-01-01

    The aqueous based reflux method useful for the green synthesis of nanostructures is described in detail. In this method, the parameters: the order of addition of precursors, the time of the reflux and the cooling rate should be optimized in order to obtain the desired phase and morphology of the nanostructures. The application of this method is discussed with reference to the synthesis of CZTS nanoparticles which have great potential as an absorber material in the photovoltaic devices. The highlights of this method are:•Simple.•Low cost.•Aqueous based. PMID:27408826

  9. Evaluation of Direct Aqueous Injection Method for Analysis of Chloroform in Drinking Water

    ERIC Educational Resources Information Center

    Pfaender, Frederic K.; And Others

    1978-01-01

    A direct aqueous injection (DAI) technique was compared with the purge method for chloroform measurement in drinking water. The DAI method gave consistently higher values for chloroform than the purge method. The results indicated the need for caution in the interpretation of chloroform and other trihalomethane values generated by DAI. (Author/MA)

  10. Method for Non-Invasive Determination of Chemical Properties of Aqueous Solutions

    NASA Technical Reports Server (NTRS)

    Todd, Paul W. (Inventor); Jones, Alan (Inventor); Thomas, Nathan A. (Inventor)

    2016-01-01

    A method for non-invasively determining a chemical property of an aqueous solution is provided. The method provides the steps of providing a colored solute having a light absorbance spectrum and transmitting light through the colored solute at two different wavelengths. The method further provides the steps of measuring light absorbance of the colored solute at the two different transmitted light wavelengths, and comparing the light absorbance of the colored solute at the two different wavelengths to determine a chemical property of an aqueous solution.

  11. Modeling of fluid injection and withdrawal induced fault activation using discrete element based hydro-mechanical and dynamic coupled simulator

    NASA Astrophysics Data System (ADS)

    Yoon, Jeoung Seok; Zang, Arno; Zimmermann, Günter; Stephansson, Ove

    2016-04-01

    Operation of fluid injection into and withdrawal from the subsurface for various purposes has been known to induce earthquakes. Such operations include hydraulic fracturing for shale gas extraction, hydraulic stimulation for Enhanced Geothermal System development and waste water disposal. Among these, several damaging earthquakes have been reported in the USA in particular in the areas of high-rate massive amount of wastewater injection [1] mostly with natural fault systems. Oil and gas production have been known to induce earthquake where pore fluid pressure decreases in some cases by several tens of Mega Pascal. One recent seismic event occurred in November 2013 near Azle, Texas where a series of earthquakes began along a mapped ancient fault system [2]. It was studied that a combination of brine production and waste water injection near the fault generated subsurface pressures sufficient to induced earthquakes on near-critically stressed faults. This numerical study aims at investigating the occurrence mechanisms of such earthquakes induced by fluid injection [3] and withdrawal by using hydro-geomechanical coupled dynamic simulator (Itasca's Particle Flow Code 2D). Generic models are setup to investigate the sensitivity of several parameters which include fault orientation, frictional properties, distance from the injection well to the fault, amount of fluid withdrawal around the injection well, to the response of the fault systems and the activation magnitude. Fault slip movement over time in relation to the diffusion of pore pressure is analyzed in detail. Moreover, correlations between the spatial distribution of pore pressure change and the locations of induced seismic events and fault slip rate are investigated. References [1] Keranen KM, Weingarten M, Albers GA, Bekins BA, Ge S, 2014. Sharp increase in central Oklahoma seismicity since 2008 induced by massive wastewater injection, Science 345, 448, DOI: 10.1126/science.1255802. [2] Hornbach MJ, DeShon HR

  12. Seismic Versus Aseismic Slip and Maximum Induced Earthquake Magnitude in Models of Faults Stimulated by Fluid Injection

    NASA Astrophysics Data System (ADS)

    Ampuero, J. P.; Cappa, F.; Galis, M.; Mai, P. M.

    2015-12-01

    The assessment of earthquake hazard induced by fluid injection or withdrawal could be advanced by understanding what controls the maximum magnitude of induced seismicity (Mmax) and the conditions leading to aseismic instead of seismic slip. This is particularly critical for the viability of renewable energy extraction through engineered geothermal systems, which aim at enhancing permeability through controlled fault slip. Existing empirical relations and models for Mmax lack a link between rupture size and the characteristics of the triggering stress perturbation based on earthquake physics. We aim at filling this gap by extending results on the nucleation and arrest of dynamic rupture. We previously derived theoretical relations based on fracture mechanics between properties of overstressed nucleation regions (size, shape and overstress level), the ability of dynamic ruptures to either stop spontaneously or run away, and the final size of stopping ruptures. We verified these relations by comparison to 3D dynamic rupture simulations under slip-weakening friction and to laboratory experiments of frictional sliding nucleated by localized stresses. Here, we extend these results to the induced seismicity context by considering the effect of pressure perturbations resulting from fluid injection, evaluated by hydromechanical modeling. We address the following question: given the amplitude and spatial extent of a fluid pressure perturbation, background stress and fracture energy on a fault, does a nucleated rupture stop spontaneously at some distance from the pressure perturbation region or does it grow away until it reaches the limits of the fault? We present fracture mechanics predictions of the rupture arrest length in this context, and compare them to results of 3D dynamic rupture simulations. We also conduct a systematic study of the effect of localized fluid pressure perturbations on faults governed by rate-and-state friction. We investigate whether injection

  13. Method for removing trace pollutants from aqueous solutions

    DOEpatents

    Silver, G.L.

    A method of substantially removing a trace metallic contaminant from a liquid containing the same comprises: adding an oxidizing agent to a liquid containing a trace amount of a metallic contaminant of a concentration of up to about 0.1 ppM, and separating the homogeneously precipitated product from the liquid.

  14. Effects of Long-Term Fluid Injection on Maximum Magnitude and Induced Seismicity Parameters at Northwestern The Geysers Geothermal Field

    NASA Astrophysics Data System (ADS)

    Bohnhoff, M.; Kwiatek, G.; Martínez-Garzón, P.; Dresen, G. H.; Sone, H.; Hartline, C. S.

    2015-12-01

    The long-term temporal and spatial changes in statistical, source and stress characteristics of one cluster of induced seismicity recorded at The Geysers geothermal field (US) are analyzed in relation to the field operations, fluid migration and constraints on the maximum likely magnitude. Two injection wells, Prati-9 and Prati-29, located in the northwestern part of the field and their associated seismicity composed of 1,776 events recorded throughout a seven-year period were analyzed. The seismicity catalog was relocated and the source characteristics including focal mechanisms and static source parameters were refined using first-motion polarity, spectral fitting and mesh spectral ratio techniques. The source characteristics together with statistical parameters (b-value) and cluster dynamics were used to investigate and understand the details of fluid migration scheme in the vicinity of injection wells. The observed temporal, spatial and source characteristics were clearly attributed to fluid injection and fluid migration towards greater depths, involving increasing pore pressure in the reservoir. Increasing poroelastic stresses at greater depths affect the kinematic properties of the seismicity in that at reservoir depths normal faulting mechanism events dominate, whereas at larger depths the contribution of strike-slip events are is significantly increasing. The seasonal changes of injection rates were found to directly impact the shape and spatial extent of the seismic cloud. A tendency of larger seismic events to occur closer to injection wells and a correlation between the spatial extent of the seismic cloud and source sizes of the largest events was observed suggesting geometrical constraints on the maximum likely magnitude. The observed maximum magnitude was found to be clearly correlated to the dimensions of seismic cloud which is related to the volume of formation weakened by fluid injection and injection rate, and the average pore pressure change in

  15. Synthetic modeling of a fluid injection-induced fault rupture with slip-rate dependent friction coefficient

    NASA Astrophysics Data System (ADS)

    Urpi, Luca; Rinaldi, Antonio Pio; Rutqvist, Jonny; Cappa, Frédéric; Spiers, Christopher J.

    2016-04-01

    Poro-elastic stress and effective stress reduction associated with deep underground fluid injection can potentially trigger shear rupture along pre-existing faults. We modeled an idealized CO2 injection scenario, to assess the effects on faults of the first phase of a generic CO2 aquifer storage operation. We used coupled multiphase fluid flow and geomechanical numerical modeling to evaluate the stress and pressure perturbations induced by fluid injection and the response of a nearby normal fault. Slip-rate dependent friction and inertial effects have been aken into account during rupture. Contact elements have been used to take into account the frictional behavior of the rupture plane. We investigated different scenarios of injection rate to induce rupture on the fault, employing various fault rheologies. Published laboratory data on CO2-saturated intact and crushed rock samples, representative of a potential target aquifer, sealing formation and fault gouge, have been used to define a scenario where different fault rheologies apply at different depths. Nucleation of fault rupture takes place at the bottom of the reservoir, in agreement with analytical poro-elastic stress calculations, considering injection-induced reservoir inflation and the tectonic scenario. For the stress state here considered, the first triggered rupture always produces the largest rupture length and slip magnitude, correlated with the fault rheology. Velocity weakening produces larger ruptures and generates larger magnitude seismic events. Heterogeneous faults have been considered including velocity-weakening or velocity strengthening sections inside and below the aquifer, while upper sections being velocity-neutral. Nucleation of rupture in a velocity strengthening section results in a limited rupture extension, both in terms of maximum slip and rupture length. For a heterogeneous fault with nucleation in a velocity-weakening section, the rupture may propagate into the overlying velocity

  16. Nickel/ruthenium catalyst and method for aqueous phase reactions

    DOEpatents

    Elliott, Douglas C.; Sealock, John L.

    1998-01-01

    A method of hydrogenation using a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional ruthenium metal deposited onto the support in a second dispersed phase. The additional ruthenium metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase thereby increasing the life time of the catalyst during hydrogenation reactions.

  17. Nickel/ruthenium catalyst and method for aqueous phase reactions

    DOEpatents

    Elliott, D.C.; Sealock, J.L.

    1998-09-29

    A method of hydrogenation is described using a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional ruthenium metal deposited onto the support in a second dispersed phase. The additional ruthenium metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase thereby increasing the life time of the catalyst during hydrogenation reactions. 2 figs.

  18. Method for removing trace pollutants from aqueous solutions

    DOEpatents

    Silver, Gary L.

    1986-01-01

    A method of substantially removing a trace metallic contaminant from a liquid containing the same comprises, adding an oxidizing agent to a liquid containing a trace amount of a metallic contaminant of a concentration of up to about 10.sup.-1 ppm, the oxidizing agent being one which oxidizes the contaminant to form an oxidized product which is insoluble in the liquid and precipitates therefrom, and the conditions of the addition being selected to ensure that the precipitation of the oxidized product is homogeneous, and separating the homogeneously precipitated product from the liquid.

  19. Method for removing and decolorizing aqueous waste effluents containing dissolved or dispersed organic matter

    DOEpatents

    Case, F.N.; Ketchen, E.E.

    1975-10-14

    A method is provided for treating organic waste material dissolved or dispersed in an aqueous effluent, which comprises contacting the effluent with an inert particulate carbonaceous sorbent at an oxygen pressure up to 2000 psi, irradiating the resultant mixture with high energy radiation until a decolorized liquid is produced, and then separating the decolorized liquid.

  20. Universal Method to Transfer Membrane-Templated Nano-Objects to Aqueous Solutions.

    PubMed

    Saghazadeh, Saghi; Zhang, Shouwei; Lefèvre, Damien; Le Beulze, Aurélie; Jonas, Alain M; Demoustier-Champagne, Sophie

    2015-07-01

    A wide range of nano-objects are synthesized by combining template synthesis, using polycarbonate membrane as template, with different material deposition methods. The resulting nanostructures varied from robust inorganic gold nanowires grown by electrodeposition to rigid polypyrrole nanotubes synthesized by chemical polymerization and softer nanotubes made of different combinations of synthetic and natural polyelectrolytes fabricated by layer-by-layer (LbL) assembly. The morphology of these various nano-objects is characterized prior to and after their immersion in water, revealing that the rigidity degree of LbL nanotubes strongly decreases after being in contact with water, leading to highly swollen and flexible nanotubes in aqueous solution that tend to stick to any surface and are very difficult to collect and disperse quantitatively in aqueous solution. Different processes to collect these nano-objects and disperse them in aqueous medium for further analysis and application were then studied. Among them, a method based on simple filtration of nanotubes in the presence of a powdered dextran adjuvant leads to the quantitative collection and dispersion in water of all types of tested cylindrical nano-objects. This universal method to efficiently collect membrane templated nano-objects paves the way to further characterization of a large variety of nanotubes in aqueous solution and to their potential use as cargo nanocarriers or as nanoreactors.

  1. Method for separating water soluble organics from a process stream by aqueous biphasic extraction

    DOEpatents

    Chaiko, David J.; Mego, William A.

    1999-01-01

    A method for separating water-miscible organic species from a process stream by aqueous biphasic extraction is provided. An aqueous biphase system is generated by contacting a process stream comprised of water, salt, and organic species with an aqueous polymer solution. The organic species transfer from the salt-rich phase to the polymer-rich phase, and the phases are separated. Next, the polymer is recovered from the loaded polymer phase by selectively extracting the polymer into an organic phase at an elevated temperature, while the organic species remain in a substantially salt-free aqueous solution. Alternatively, the polymer is recovered from the loaded polymer by a temperature induced phase separation (cloud point extraction), whereby the polymer and the organic species separate into two distinct solutions. The method for separating water-miscible organic species is applicable to the treatment of industrial wastewater streams, including the extraction and recovery of complexed metal ions from salt solutions, organic contaminants from mineral processing streams, and colorants from spent dye baths.

  2. Preserving drinking water quality in geotechnical operations: predicting the feedback between fluid injection, fluid flow, and contamination

    NASA Astrophysics Data System (ADS)

    Schilling, Frank R.

    2014-05-01

    Not only in densely populated areas the preservation of drinking water quality is of vital interest. On the other side, our modern economies request for a sustained energy supply and a secure storage of waste materials. As energy sources with a high security of supply, oil, natural gas, and geothermal energy cover ca. 60% of Europe's energy demand; together with coal more than 75% (IEA 2011). Besides geothermal energy, all of the resources have a high greenhouse gas footprint. All these production activities are related to fluid injection and/or fluid production. The same holds true for gas storage operations in porous reservoirs, to store natural gases, oil, or greenhouse gases. Different concerns are discussed in the public and geoscientific community to influence the drinking water quality: - wastewater discharges from field exploration, drilling, production, well treatment and completion - wastewater sequestration - gas storage - tight gas and tight oil production (including hydraulic fracturing) - Shale gas production (including hydraulic fracturing) - mine drainage This overview contribution focusses on strategies to systematically reduce the risk of water pollution in geotechnical operations of deep reservoirs. The principals will be exemplarily revealed for different geotechnical operations. - How to control hydraulic fracturing operations to reduce the risk of enhanced seismic activity and avoiding the connection of originally separated aquifers. The presented approach to quantitatively predict the impact of stimulation activities is based on petrophysical models taking the feedback of geomechanical processes and fluid flow in porous media, fissures and faults into account. The specific flow patterns in various rock types lead to distinguished differences in operational risk. - How can a proper planning of geotechnical operations reduce the involved risks. A systematic risk reduction strategy will be discussed. On selected samples the role of exploration

  3. [Absorption of aqueous extracts from Salviae Miltiorrhizae Radix et Rhizoma by everted intestinal sac method].

    PubMed

    Zhao, Jie; Xu, Xue-lin; Yi, Hong; Zhang, Hong-min; Liu, Xiao-qian; Zhu, Jing-jing; Wang, Zhi-min

    2015-08-01

    To study the absorptive characteristics of aqueous extracts from Salviae Miltiorrhizae Radix et Rhizoma by in vitro rat everted intestinal sac model. Three representative ingredients in aqueous extracts from Salviae Miltiorrhizae Radix et Rhizome--protocatechuic aldehyde (PAL), posmarinic acid (RA) and salvianolic acid B (SAB), were selected as the study objects. An UPLC method was established to determine and measure their cumulative absorption amount, in order to explain the absorption characteristics of ingredients in different intestinal sections. According to the experimental result, RA and SAB showed the passive absorption in ileum, which conformed to the first-order absorption rate; with low and medium doses, they showed a zero-order absorption rate in jejunum, which was reflected in the coexistence of both positive and passive absorptions; PAL showed a passive absorption manner both in ileum and jejunum. According to the experiment for absorption in different intestinal sections, RA and SAB were mainly absorbed in jejunum, while PAL was absorbed mainly in ileum. All of the three ingredients in aqueous extracts from Salviae Miltiorrhizae Radix et rhizome--PAL, RA and SAB could be absorbed in intestines, but with differences in the absorption rate and mechanism, which indicated that the intestinal absorption of aqueous extracts from Salviae Miltiorrhizae Radix et rhizome was selectivity, instead of a simple semi-permeable membrane penetration process.

  4. Method and apparatus for measuring volatile compounds in an aqueous solution

    DOEpatents

    Gilmore, Tyler J [Pasco, WA; Cantrell, Kirk J [West Richland, WA

    2002-07-16

    The present invention is an improvement to the method and apparatus for measuring volatile compounds in an aqueous solution. The apparatus is a chamber with sides and two ends, where the first end is closed. The chamber contains a solution volume of the aqueous solution and a gas that is trapped within the first end of the chamber above the solution volume. The gas defines a head space within the chamber above the solution volume. The chamber may also be a cup with the second end. open and facing down and submerged in the aqueous solution so that the gas defines the head space within the cup above the solution volume. The cup can also be entirely submerged in the aqueous solution. The second end of the. chamber may be closed such that the chamber can be used while resting on a flat surface such as a bench. The improvement is a sparger for mixing the gas with the solution volume. The sparger can be a rotating element such as a propeller on a shaft or a cavitating impeller. The sparger can also be a pump and nozzle where the pump is a liquid pump and the nozzle is a liquid spray nozzle open, to the head space for spraying the solution volume into the head space of gas. The pump could also be a gas pump and the nozzle a gas nozzle submerged in the solution volume for spraying the head space gas into the solution volume.

  5. Validation of a GC-MS screening method for anabolizing agents in aqueous nutritional supplements.

    PubMed

    Thuyne, W Van; Delbeke, F T

    2005-01-01

    A sensitive and selective method for the screening of anabolizing agents in aqueous nutritional supplements is described and validated. A total of 28 different anabolizing agents are screened for, including testosterone and prohormones, nandrolone and prohormones, stanozolol, and metandienone. The different analytes are extracted from the aqueous nutritional supplements by liquid-liquid extraction with a mixture of pentane and freshly distilled diethylether (1:1) after the supplements have been made alkaline with a NaHCO3-K2CO3 (2:1) buffer. The anabolizing agents are derivatized with a mixture of MSTFA-NH4I-ethanethiol (320:1:2) as routinely used for the screening of anabolic steroids extracted from urine. The derivatives are analyzed by gas chromatography (GC)-mass spectrometry (MS) in the selective ion monitoring mode. The limits of detection range from 1 to 10 ng/mL. One aqueous nutritional supplement (creatine serum) was analyzed with this screening method and was found to contain dehydroepiandrosterone (DHEA) at very low concentrations. The presence of DHEA could be confirmed with GC-MS-MS. Results of the application of this method and a similar method for solid nutritional supplements previously described are given. PMID:15808000

  6. Modeling and investigation of refrigeration system performance with two-phase fluid injection in a scroll compressor

    NASA Astrophysics Data System (ADS)

    Gu, Rui

    Vapor compression cycles are widely used in heating, refrigerating and air-conditioning. A slight performance improvement in the components of a vapor compression cycle, such as the compressor, can play a significant role in saving energy use. However, the complexity and cost of these improvements can block their application in the market. Modifying the conventional cycle configuration can offer a less complex and less costly alternative approach. Economizing is a common modification for improving the performance of the refrigeration cycle, resulting in decreasing the work required to compress the gas per unit mass. Traditionally, economizing requires multi-stage compressors, the cost of which has restrained the scope for practical implementation. Compressors with injection ports, which can be used to inject economized refrigerant during the compression process, introduce new possibilities for economization with less cost. This work focuses on computationally investigating a refrigeration system performance with two-phase fluid injection, developing a better understanding of the impact of injected refrigerant quality on refrigeration system performance as well as evaluating the potential COP improvement that injection provides based on refrigeration system performance provided by Copeland.

  7. Quantitative infrared spectroscopic method for the study of the hydration of ions in aqueous solutions

    SciTech Connect

    Kristiansson, O.; Lindgren, J.; de Villepin, J.

    1988-05-05

    An infrared spectroscopic method for the study of the hydration of ions in aqueous solutions has been developed. OD stretching bands of isotopically dilute HDO molecules in the first hydration sphere of ions are obtained when the absorption from H/sub 2/O molecules and HDO molecules in the bulk water are removed by a double difference technique. The method is applied to aqueous solutions of Ni(ClO/sub 4/)/sub 2/, Ni(BF/sub 4/)/sub 2/, and Ni(PF/sub 6/)/sub 2/. Coordination numbers of 4.6 +/- 0.8 for the ClO/sub 4//sup -/ anion and 3.9 +/- 0.8 for the BF/sub 4//sup -/ anion are obtained. A systematic study of the influence of different salt and HDO concentrations has been undertaken. It is found that Lambert-Beer's law is valid in the concentration ranges studied.

  8. Droplet formation and shrinking in aqueous two-phase systems using a membrane emulsification method

    PubMed Central

    Breisig, Hans; Wessling, Matthias

    2015-01-01

    Using a membrane emulsification method based on porous hollow-fiber membranes in combination with an aqueous two-phase system (ATPS), we are able to produce “water-in-water” droplets with narrow-dispersed size distributions. The equilibrium phases of the aqueous two-phase system polyethylene glycol-dipotassium hydrogen phosphate are used for this purpose. The droplet diameter of a given fluid system is determined by the flow rates of the continuous and disperse phase as well as the hollow fiber dimensions. When diluting the disperse phase and thus moving the ATPS system out of equilibrium, the droplet size can be further reduced in comparison to the equilibrium case. Generally, droplets formed with this method have diameters 20%–60% larger than the inner hollow fiber diameter. The new strategy of diluting the disperse phase allows the production of droplet diameter below the inner diameter of the membrane. PMID:26339321

  9. EM Earthquake Precursor Detection Associated with Fluid Injection for Hydraulic Fracturing and Tectonic Sources

    NASA Astrophysics Data System (ADS)

    Jones, Kenneth B., II

    2015-04-01

    Many attempts have been made to determine an earthquake forecasting method and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic wave model, various hypotheses were formed, but only two seemed to take shape with the most interesting one requiring a magnetometer of a unique design. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, results have had wide variability and problems still reside with what exactly is forecastable and the investigative direction of a true precursor. After a number of custom rock experiments, the two hypotheses were thoroughly tested to correlate the EM wave model. The first hypothesis involved sufficient and continuous electron movement either by surface or penetrative flow, and the second regarded a novel approach to radio wave generation. The second hypothesis resulted best with highly reproducible data, radio wave generation and detection, and worked numerous times with each laboratory test administered. In addition, internally introduced force on a small scale stressed a number of select rock types to emit radio waves well before catastrophic failure, and failure always went to completion. Comparatively, at a larger scale, highly detailed studies were procured to establish legitimate wave guides from potential hypocenters to epicenters and map the results, accordingly. Field testing in Southern California from 2006 to 2011 and outside the NE Texas town of Timpson in February, 2013 was conducted for detecting similar, laboratory generated, radio wave sources. At the Southern California field sites, signals were detected in numerous directions with varying amplitudes; therefore, a reactive approach was investigated in hopes of detecting possible aftershocks from large, tectonically related M5.0+ earthquakes. At the Timpson

  10. Magnetotelluric monitoring of a fluid injection: Example from an enhanced geothermal system

    NASA Astrophysics Data System (ADS)

    Peacock, J. R.; Thiel, S.; Reid, P.; Heinson, G.

    2012-09-01

    Enhanced geothermal systems (EGS) are on the verge of becoming commercially viable for power production, where advancements in subsurface characterization are imperative to develop EGS into a competitive industry. Theory of an EGS is simple, pump fluids into thermally enhanced lithology and extract the hot fluids to produce energy. One significant complication in EGS development is estimating where injected fluids flow in the subsurface. Micro-seismic surveys can provide information about where fractures opened, but not fracture connectivity nor fluid inclusion. Electromagnetic methods are sensitive to conductivity contrasts and can be used as a supplementary tool to delineate reservoir boundaries. In July, 2011, an injection test for a 3.6 km deep EGS at Paralana, South Australia was continuously monitored by both micro-seismic and magnetotellurics (MT). Presented are the first results from continuous MT measurements suggesting transient variations in subsurface conductivity structure generated from the introduction of fluids at depth can be measured. Furthermore, phase tensor representation of the time dependent MT response suggests fluids migrated in a NE direction from the injection well. Results from this experiment supports the extension of MT to a monitoring tool for not only EGS but other hydraulic stimulations.

  11. Ruthenium on rutile catalyst, catalytic system, and method for aqueous phase hydrogenations

    DOEpatents

    Elliot, Douglas C.; Werpy, Todd A.; Wang, Yong; Frye, Jr., John G.

    2001-01-01

    An essentially nickel- and rhenium-free catalyst is described comprising ruthenium on a titania support where the titania is greater than 75% rutile. A catalytic system containing a nickel-free catalyst comprising ruthenium on a titania support where the titania is greater than 75% rutile, and a method using this catalyst in the hydrogenation of an organic compound in the aqueous phase is also described.

  12. Numerical modeling of the source mechanism for microseismic events induced during fluid injection

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Reyes-Montes, J.; Young, R.

    2013-12-01

    Passive microseismic (MS) monitoring is now common practice for imaging and real-time feedback of geological reservoir stimulation operations in a number of energy sectors. MS locations provide first-hand information of the fracture network geometry and propagation; however a full understanding of the fundamental processes of induced fracturing requires the use of additional information contained in the recorded waveforms. One of the current challenges is robustly solving the focal mechanism of recorded MS events from a sparse array, such as single borehole linear arrays. In this study, a synthetic rock mass model (SRM), a distinct element method, was developed to model typical source fracturing modes associated with reservoir stimulation, including shear dislocation (strike-slip and dip-slip), dilation (tensile), and explosion. The body forces directly exerted by source particles were monitored using linear sets of particle arrays simulating the sensors in field operations. The disturbance at each receiver (particle in the model) was recorded in three orthogonal directions to get 3-component waveforms. The model was validated analysing source mechanisms using a moment tensor inversion of P-wave time-domain amplitudes. The fault plane solution was also calculated from the distribution of P-wave first-break polarities. The moment tensor was then decomposed into eigenvalues and eigenvectors representing the principal axes (pressure, null and tension) of the source. Percentage isotropic, double-couple and compensated linear vector dipole components were calculated, along with orientations of the fault plane solution. The inverted moment and fault plane solutions show the similar failure modes to the source motion applied to the fault plane. This shows that the modelling approach can be used to combine different basic source modes to build a database that provides a tool to directly compare modelled and field data in order to probabilistically estimate a feasible focal

  13. Aqueous processing of low-band-gap polymer solar cells using roll-to-roll methods.

    PubMed

    Andersen, Thomas R; Larsen-Olsen, Thue T; Andreasen, Birgitta; Böttiger, Arvid P L; Carlé, Jon E; Helgesen, Martin; Bundgaard, Eva; Norrman, Kion; Andreasen, Jens W; Jørgensen, Mikkel; Krebs, Frederik C

    2011-05-24

    Aqueous nanoparticle dispersions of a series of three low-band-gap polymers poly[4,8-bis(2-ethylhexyloxy)benzo(1,2-b:4,5-b')dithiophene-alt-5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)(2,1,3-benzothiadiazole)-5,5'-diyl] (P1), poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (P2), and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (P3) were prepared using ultrasonic treatment of a chloroform solution of the polymer and [6,6]-phenyl-C(61)-butyric acid methyl ester ([60]PCBM) mixed with an aqueous solution of sodium dodecylsulphate (SDS). The size of the nanoparticles was established using small-angle X-ray scattering (SAXS) of the aqueous dispersions and by both atomic force microscopy (AFM) and using both grazing incidence SAXS (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS) in the solid state as coated films. The aqueous dispersions were dialyzed to remove excess detergent and concentrated to a solid content of approximately 60 mg mL(-1). The formation of films for solar cells using the aqueous dispersion required the addition of the nonionic detergent FSO-100 at a concentration of 5 mg mL(-1). This enabled slot-die coating of high quality films with a dry thickness of 126 ± 19, 500 ± 25, and 612 ± 22 nm P1, P2, and P3, respectively for polymer solar cells. Large area inverted polymer solar cells were thus prepared based on the aqueous inks. The power conversion efficiency (PCE) reached for each of the materials was 0.07, 0.55, and 0.15% for P1, P2, and P3, respectively. The devices were prepared using coating and printing of all layers including the metal back electrodes. All steps were carried out using roll-to-roll (R2R) slot-die and screen printing methods on flexible substrates. All five layers were processed using environmentally friendly methods and solvents. Two of the layers were processed entirely from water (the electron transport layer and the active

  14. Aqueous processing of low-band-gap polymer solar cells using roll-to-roll methods.

    PubMed

    Andersen, Thomas R; Larsen-Olsen, Thue T; Andreasen, Birgitta; Böttiger, Arvid P L; Carlé, Jon E; Helgesen, Martin; Bundgaard, Eva; Norrman, Kion; Andreasen, Jens W; Jørgensen, Mikkel; Krebs, Frederik C

    2011-05-24

    Aqueous nanoparticle dispersions of a series of three low-band-gap polymers poly[4,8-bis(2-ethylhexyloxy)benzo(1,2-b:4,5-b')dithiophene-alt-5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)(2,1,3-benzothiadiazole)-5,5'-diyl] (P1), poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (P2), and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (P3) were prepared using ultrasonic treatment of a chloroform solution of the polymer and [6,6]-phenyl-C(61)-butyric acid methyl ester ([60]PCBM) mixed with an aqueous solution of sodium dodecylsulphate (SDS). The size of the nanoparticles was established using small-angle X-ray scattering (SAXS) of the aqueous dispersions and by both atomic force microscopy (AFM) and using both grazing incidence SAXS (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS) in the solid state as coated films. The aqueous dispersions were dialyzed to remove excess detergent and concentrated to a solid content of approximately 60 mg mL(-1). The formation of films for solar cells using the aqueous dispersion required the addition of the nonionic detergent FSO-100 at a concentration of 5 mg mL(-1). This enabled slot-die coating of high quality films with a dry thickness of 126 ± 19, 500 ± 25, and 612 ± 22 nm P1, P2, and P3, respectively for polymer solar cells. Large area inverted polymer solar cells were thus prepared based on the aqueous inks. The power conversion efficiency (PCE) reached for each of the materials was 0.07, 0.55, and 0.15% for P1, P2, and P3, respectively. The devices were prepared using coating and printing of all layers including the metal back electrodes. All steps were carried out using roll-to-roll (R2R) slot-die and screen printing methods on flexible substrates. All five layers were processed using environmentally friendly methods and solvents. Two of the layers were processed entirely from water (the electron transport layer and the active

  15. Method and device for removing a non-aqueous phase liquid from a groundwater system

    DOEpatents

    Looney, Brian B.; Rossabi, Joseph; Riha, Brian D.

    2002-01-01

    A device for removing a non-aqueous phase liquid from a groundwater system includes a generally cylindrical push-rod defining an internal recess therein. The push-rod includes first and second end portions and an external liquid collection surface. A liquid collection member is detachably connected to the push-rod at one of the first and second end portions thereof. The method of the present invention for removing a non-aqueous phase liquid from a contaminated groundwater system includes providing a lance including an external hydrophobic liquid collection surface, an internal recess, and a collection chamber at the bottom end thereof. The lance is extended into the groundwater system such that the top end thereof remains above the ground surface. The liquid is then allowed to collect on the liquid collection surface, and flow downwardly by gravity into the collection chamber to be pumped upwardly through the internal recess in the lance.

  16. Ludwig-Soret effect of non-ionic surfactant aqueous solution studied by beam deflection method

    NASA Astrophysics Data System (ADS)

    Maeda, Kousaku; Kita, Rio; Shinyashiki, Naoki; Yagihara, Shin

    2013-02-01

    We have studied the thermal diffusion of non-ionic surfactant aqueous solutions by a beam deflection method. The thermal diffusion of pentaethylene glycol monododecyl ether (C12E5) and hexaethylene glycol monododecyl ether (C12E6) is studied in the concentration range of 1.0-99.0 wt% and in the temperature range of 20.0-35.0 °C. A stable temperature gradient is applied to the solution, where solute molecules shift to the cold side of the solution for lowconcentration samples. The concentration dependence of the Soret coefficient ST of the C12E6 aqueous solution shows a sign inversion behavior. At all concentrations, the developed concentration gradient is proportionally related to the applied temperature gradient. The results confirm that the magnitude of ST has no temperature gradient dependence under the studied experimental conditions.

  17. Fluid injection microvalve

    DOEpatents

    Renzi, Ronald F.

    2005-11-22

    A microvalve for extracting small volume samples into analytical devices, e.g., high pressure liquid chromatography (HPLC) column, includes: a first body having a first interior surface and two or more outlet ports at the first interior surface that are in fluid communication with two or more first channels; a second body having a second interior surface and two or more inlet ports at the second interior surface that are in fluid communication with two or more second channels wherein the outlet ports of the first body are coaxial with the corresponding inlet ports of the second body such that there are at least two sets of coaxial port outlets and port inlets; a plate member, which has a substantially planar first mating surface and a substantially planar second mating surface, that is slidably positioned between the first interior surface and the second interior surface wherein the plate member has at least one aperture that traverses the height of the plate member, and wherein the aperture can be positioned to be coaxial with any of the at least two sets of coaxial port outlets and port inlets; and means for securing the first surface of the first body against the first mating surface and for securing the second surface of the second body against the second mating surface.

  18. Method for the removal of ultrafine particulates from an aqueous suspension

    DOEpatents

    Chaiko, David J.; Kopasz, John P.; Ellison, Adam J. G.

    2000-01-01

    A method of separating ultra-fine particulates from an aqueous suspension such as a process stream or a waste stream. The method involves the addition of alkali silicate and an organic gelling agent to a volume of liquid, from the respective process or waste stream, to form a gel. The gel then undergoes syneresis to remove water and soluble salts from the gel containing the particulates, thus, forming a silica monolith. The silica monolith is then sintered to form a hard, nonporous waste form.

  19. Method for the Removal of Ultrafine Particulates from an Aqueous Suspension

    SciTech Connect

    Chaiko, David J.; Kopasz, John P.; Ellison, Adam J.G.

    1999-03-05

    A method of separating ultra-fine particulate from an aqueous suspension such as a process stream or a waste stream. The method involves the addition of alkali silicate and an organic gelling agent to a volume of liquid, from the respective process or waste stream, to form a gel. The gel then undergoes syneresis to remove water and soluble salts from the gel-containing the particulate, thus, forming a silica monolith. The silica monolith is then sintered to form a hard, nonporous waste form.

  20. Polymer incorporation method affects the physical stability of amorphous indomethacin in aqueous suspension.

    PubMed

    Surwase, S A; Itkonen, L; Aaltonen, J; Saville, D; Rades, T; Peltonen, L; Strachan, C J

    2015-10-01

    This study reports the potential of different polymers and polymer incorporation methods to inhibit crystallisation and maintain supersaturation of amorphous indomethacin (IND) in aqueous suspensions during storage. Three different polymers (poly(vinyl pyrrolidone) (PVP), hydroxypropyl methylcellulose (HPMC) and Soluplus® (SP)) were used and included in the suspensions either as a solid dispersion (SD) with IND or dissolved in the suspension medium prior to the addition of amorphous IND. The total concentrations of both IND and the polymer in the suspensions were kept the same for both methods of polymer incorporation. All the polymers (with both incorporation methods) inhibited crystallisation of the amorphous IND. The SDs were better than the predissolved polymer solutions at inhibiting crystallisation. The SDs were also better at maintaining drug supersaturation. SP showed a higher IND crystallisation inhibition and supersaturation potential than the other polymers. However, this depended on the method of addition. IND in SD with SP did not crystallise, nor did the SD generate any drug supersaturation, whereas IND in the corresponding predissolved SP solution crystallised (into the recently characterised η polymorphic form of the drug) but also led to a more than 20-fold higher IND solution concentration than that observed for crystalline IND. The ranking of the polymers with respect to crystallisation inhibition potential in SDs was SP≫PVP>HPMC. Overall, this study showed that both polymer type and polymer incorporation method strongly impact amorphous form stability and drug supersaturation in aqueous suspensions. PMID:26092472

  1. Method and apparatus for controlled size distribution of gel microspheres formed from aqueous dispersions. [Patent application

    DOEpatents

    Ryon, A.D.; Haas, P.A.; Vavruska, J.S.

    1982-01-19

    The present invention is directed to a method and apparatus for making a population of dense, closely size-controlled microspheres by sol-gel procedures wherein said microspheres are characterized by a significant percentage of said population being within a predetermined, relatively narrow size range. This is accomplished by subjecting aqueous dispersions of a sol, within a water-immiscible organic liquid to a turbulent flow. Microsphere populations thus provided are useful in vibratory-packed processes for nuclear fuels to be irradiated in LWR- and FBR-type nuclear reactors.

  2. Photochemical method for generating superoxide radicals (O.sub.2.sup.-) in aqueous solutions

    DOEpatents

    Holroyd, Richard A.; Bielski, Benon H. J.

    1980-01-01

    A photochemical method and apparatus for generating superoxide radicals (ub.2.sup.-) in an aqueous solution by means of a vacuum-ultraviolet lamp of simple design. The lamp is a microwave powered rare gas device that emits far-ultraviolet light. The lamp includes an inner loop of high purity quartz tubing through which flows an oxygen-saturated sodium formate solution. The inner loop is designed so that the solution is subjected to an intense flux of far-ultraviolet light. This causes the solution to photodecompose and form the product radical (O.sub.2.sup.-).

  3. A validated stability-indicating HPLC method for the determination of PEGylated puerarin in aqueous solutions.

    PubMed

    Liu, Xinyi; Yu, Boyang; Wang, Naijie; Zhang, Bei; Du, Feng; He, Cheng; Ye, Zuguang

    2010-08-01

    The aim of this study was to develop a validated specific stability-indicating HPLC method for the quantitative determination of PEGylated puerarin (PEG-PUE) in aqueous solutions. The method was validated by subjecting PEG-PUE to forced degradation under stress conditions of acid, alkali, water hydrolysis, and oxidation. Both PEG-PUE and puerarin (PUE) were simultaneously determined and separated on CAPCELL PAK C18 column by gradient elution with 0.2% aqueous phosphoric acid and acetonitrile as the mobile phase. The flow rate was 1.0 mL min(-1) and detection wavelength was set at 250 nm. Both calibration curves showed good linear regression (r> or =0.9998) within test ranges. The LOD and LOQ of PEG-PUE were determined to be 3 and 9 microg mL(-1) respectively. Degradation of PEG-PUE followed pseudo-first-order kinetics with t(1/2) of 59 min at pH 9.0 and 17.79 h at pH 7.4. However, at pH 5.0 and 2.0, there was no significant degradation of PEG-PUE over time. In conclusion, the method was observed to have the necessary specificity, precision, and accuracy, and to be suitable for quantity monitoring the degradation process of PEG-PUE during stability studies. The degradation studies may give insight into useful information for formulation development of PEG-PUE.

  4. Development of Recombinant Human Growth Hormone (rhGH) sustained-release microspheres by a low temperature aqueous phase/aqueous phase emulsion method.

    PubMed

    Kang, Jian; Wu, Fei; Cai, Yunpeng; Xu, Mingxin; He, Mu; Yuan, Weien

    2014-10-01

    A novel method has been developed to protect Recombinant Human Growth Hormone (rhGH) in poly (lactic-co-glycolic acid) (PLGA) microspheres using an aqueous phase/aqueous phase emulsion and S/O/W multi-emulsion method. This method develops a novel rhGH sustained-release system, which is based on the combination of rhGH-loaded dextran microparticles and PLGA microspheres. The process to fabricate rhGH-loaded dextran microparticles involves an aqueous phase/aqueous phase emulsion system formed at the reduced temperature. RhGH was first dissolved in water together with dextran and polyethylene glycol, followed by stirring at the speed of 2000 rpm for 20-30s at 0°C, and then a freezing process could enable the dextran phase to separate from the continuous PEG phase and rhGH could preferentially be loaded with dextran. The sample after freezing and phase separation was then lyophilized to powder and washed with dichloromethane to remove the PEG. Once loaded in the dextran microparticles (1-4 μm in diameter), rhGH gained resistance to interface tensions and was encapsulated into PLGA microspheres without aggregation thereafter. RhGH released from PLGA microspheres was in a sustained manner with minimal burst and maximally reduced incomplete release in vitro. Single subcutaneous injection of rhGH-loaded PLGA microspheres to rats resulted in a stable plasma concentration for 30 days avoiding the drug concentration fluctuations after multiple injections of protein solutions. In a hypophysectomized rat model, the IGF-1 and bodyweight results showed that there were higher than the levels obtained for the sustained release formulation by W/O/W for 40 days. These results suggest that the microsphere delivery system had the potential to be an injectable depot for sustained-release of the biocompatible protein of rhGH.

  5. Magnetic Adsorption Method for the Treatment of Metal Contaminated Aqueous Waste

    SciTech Connect

    G. B. Cotten; J. D. Navratil; H. B. Eldredge

    1999-03-01

    There have been many recent developments in separation methods used for treating radioactive and non-radioactive metal bearing liquid wastes. These methods have included adsorption, ion exchange, solvent extraction and other chemical and physical techniques. To date very few, if any, of these processes can provide a low cost and environmentally benign solution. Recent research into the use of magnetite for wastewater treatment indicates the potential for magnetite both cost and environment drivers. A brief review of recent work in using magnetite as a sorbent is presented as well as recent work performed in our laboratory using supported magnetite in the presence of an external magnetic field. The application to groundwater and other aqueous waste streams is discussed. Recent research has focused on supporting magnetite in an economical (as compared to the magnetic polymine-epichlorohydrine resin) and inert (non-reactive, chemically or otherwise) environment that promotes both adsorption and satisfactory flow characteristics.

  6. Biosorption of malachite green from aqueous solutions by Pleurotus ostreatus using Taguchi method.

    PubMed

    Chen, Zhengsuo; Deng, Hongbo; Chen, Can; Yang, Ying; Xu, Heng

    2014-01-01

    Dyes released into the environment have been posing a serious threat to natural ecosystems and aquatic life due to presence of heat, light, chemical and other exposures stable. In this study, the Pleurotus ostreatus (a macro-fungus) was used as a new biosorbent to study the biosorption of hazardous malachite green (MG) from aqueous solutions. The effective disposal of P. ostreatus is a meaningful work for environmental protection and maximum utilization of agricultural residues.The operational parameters such as biosorbent dose, pH, and ionic strength were investigated in a series of batch studies at 25°C. Freundlich isotherm model was described well for the biosorption equilibrium data. The biosorption process followed the pseudo-second-order kinetic model. Taguchi method was used to simplify the experimental number for determining the significance of factors and the optimum levels of experimental factors for MG biosorption. Biosorbent dose and initial MG concentration had significant influences on the percent removal and biosorption capacity. The highest percent removal reached 89.58% and the largest biosorption capacity reached 32.33 mg/g. The Fourier transform infrared spectroscopy (FTIR) showed that the functional groups such as, carboxyl, hydroxyl, amino and phosphonate groups on the biosorbent surface could be the potential adsorption sites for MG biosorption. P. ostreatus can be considered as an alternative biosorbent for the removal of dyes from aqueous solutions.

  7. Ultrasonic Nebulizer Assisted LIBS: a Promising Metal Elements Detection Method for Aqueous Sample Analysis

    NASA Astrophysics Data System (ADS)

    Zhong, Shilei; Zheng, Ronger; Lu, Yuan; Cheng, Kai; Xiu, Junshan

    2015-11-01

    A newly developed approach for trace metal elements detection for aqueous samples analysis is presented in this paper. The idea of this approach is to improve ablation efficiency by transforming the liquid sample into a dense cloud of droplets using an ultrasonic nebulizer. The resulting droplets are then subjected to analysis by laser induced breakdown spectroscopy (LIBS). A purpose-built ultrasonic nebulizer assisted LIBS (UN-LIBS) system has been applied to the analysis of aqueous samples at trace levels of concentration. Experimental investigations of solution samples were carried out with various dissolved trace metal elements (Mn, Zn, Cu, Pb, Fe, Mg and Na) using this approach. The characteristics of UN-LIBS signal of the elements were investigated regarding the lifetime and S/B ratio and the calibration curves for trace metal elements analyses. The obtained LODs are comparable or much better than the LODS of the reported signal enhancement approaches when the laser pulse energy was as low as 30 mJ. The good linearity of calibration curves and the low LODs shows the potential ability of this method for metal elements analysis application. The density of the electrons was calculated by measuring the Stark width of the line of Hα. The possible mechanism of the LIBS signal enhancement of this approach was briefly discussed. supported by National Natural Science Foundation of China (No. 11104153)

  8. Biosorption of malachite green from aqueous solutions by Pleurotus ostreatus using Taguchi method

    PubMed Central

    2014-01-01

    Dyes released into the environment have been posing a serious threat to natural ecosystems and aquatic life due to presence of heat, light, chemical and other exposures stable. In this study, the Pleurotus ostreatus (a macro-fungus) was used as a new biosorbent to study the biosorption of hazardous malachite green (MG) from aqueous solutions. The effective disposal of P. ostreatus is a meaningful work for environmental protection and maximum utilization of agricultural residues. The operational parameters such as biosorbent dose, pH, and ionic strength were investigated in a series of batch studies at 25°C. Freundlich isotherm model was described well for the biosorption equilibrium data. The biosorption process followed the pseudo-second-order kinetic model. Taguchi method was used to simplify the experimental number for determining the significance of factors and the optimum levels of experimental factors for MG biosorption. Biosorbent dose and initial MG concentration had significant influences on the percent removal and biosorption capacity. The highest percent removal reached 89.58% and the largest biosorption capacity reached 32.33 mg/g. The Fourier transform infrared spectroscopy (FTIR) showed that the functional groups such as, carboxyl, hydroxyl, amino and phosphonate groups on the biosorbent surface could be the potential adsorption sites for MG biosorption. P. ostreatus can be considered as an alternative biosorbent for the removal of dyes from aqueous solutions. PMID:24620852

  9. A facile method for gold decoration of Te@CdTe nanorods in aqueous solution.

    PubMed

    Shao, Haibao; Wang, Chunlei; Wang, Zhuyuan; Li, Rongqing; Xu, Qinying; Xu, Shuhong; Jiang, Yuan; Sun, Qingfeng; Bo, Fan; Cui, Yiping

    2012-10-01

    Colloidal synthesis of metal-semiconductor hybrid nanostructures is mainly achieved in organic solution. In some applications of hybrid nanoparticles relevant in aqueous media, phase transfer of hydrophobic metal-semiconductor hybrid nanostructures is essential. In this work, we present a simple method for direct synthesis of water-soluble gold (Au) decorated Te@CdTe hybrid nanorods (NRs) at room temperature by using aqueous Te@CdTe NRs as templates, which were preformed by using CdTe nanocrystals (NCs) as precursor in the presence of hydrazine hydrate (N(2)H(4)). Our results showed that NRs were decorated with Au islands both on tips and along the surface of the NRs. The size and density of Au islands can be controlled by varying the amount of Au precursor (mixture of HAuCl(4) and thioglycolic acid (TGA)) and TGA/HAuCl(4) ratio. A possible growth mechanism for the Au decoration of Te@CdTe NRs is concluded as three steps: (1) the formation of AuTe(1.7) via the substitution reaction of Cd(2+) by Au(3+), (2) adsorption of Au-TGA complex onto the preformed AuTe(1.7) anchors and following reduction by CdTe and N(2)H(4), leading to the formation of small Au NCs, (3) Au NCs grow to bigger ones, followed by reduction of more Au precursor by N(2)H(4). PMID:22795043

  10. Determination of acidity constants of sparingly soluble drugs in aqueous solution by the internal standard capillary electrophoresis method.

    PubMed

    Cabot, Joan Marc; Fuguet, Elisabet; Rosés, Martí

    2014-12-01

    A set of 33 drugs with different solubilities, ranging from soluble to very insoluble, has been chosen in order to evaluate the performance of the internal standard CE method to determine acidity constants of compounds with limited solubility. The set of drugs tested in this work has been chosen as a function of their intrinsic solubility. For the most insoluble compounds, several analytical conditions to overcome the insolubility in aqueous buffers have been tested. This paper assesses the compound solubility limits for the IS-CE method in aqueous pKa determinations, and also compares the determined pKa s with the results from the literature data obtained by other methods. It is proved that IS-CE method determines acidity constants of sparingly soluble drugs in aqueous media (compounds with logS down to around -6), whereas other reference methods require the use of aqueous-organic solvent buffers and extrapolation procedures to obtain the aqueous pKa for the same compounds.

  11. A one-term extrapolation method for estimating equilibrium constants of aqueous reactions at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Gu, Y.; Gammons, C. H.; Bloom, M. S.

    1994-09-01

    A one-term method for extrapolating equilibrium constants for aqueous reactions is proposed which is based on the observation that the change in free energy of a well-balanced isocoulombic reaction is nearly independent of temperature. The current practice in extrapolating log K values for isocoulombic reactions is to omit the ΔCp term but include a ΔS term (i.e., the two-term extrapolation equation of LINDSAY, 1980). However, we observe that the ΔCp and ΔS terms for many isocoulombic reactions are not only small, but are often opposite in sign, and therefore tend to cancel one another. Thus, inclusion of an entropy term often yields estimates which are less accurate than omission of both terms. The one-term extrapolation technique is tested with literature data for a large number of isocoulombic reactions involving ion-ligand exchange, cation hydrolysis, acid-base neutralization, redox, and selected reactions involving solids. In most cases the extrapolated values are in excellent agreement with the experimental measurements, especially at higher temperatures where they are often more accurate than those obtained using the two-term equation of LINDSAY (1980). The results are also comparable to estimates obtained using the modified HKF model of TANGER and HELGESON (1988) and the density model of ANDERSON et al. (1991). It is also found to produce reasonable estimates for isocoulombic reactions at elevated pressure (up to P = 2 kb) and ionic strength (up to I = 1.0). The principal advantage of the one-term method is that accurate estimates of high temperature equilibrium constants may be obtained using only free energy data for the reaction of interest at one reference temperature. The principal disadvantage is that the accuracies of the estimates are somewhat dependent on the model reaction selected to balance the isocoulombic reaction. Satisfactory results are obtained for reactions that have minimal energetic, electrostatic, structural, and volumetric

  12. An improved method of determining vapor-liquid equilibria for dilute organics in aqueous solution.

    PubMed

    Kieckbusch, T G; King, C J

    1979-05-01

    Chromatographic quantitative analyses of aqueous samples containing dilute concentrations of organic solutes are frequently confounded by sorption phenomena, particularly for vapor samples and aged syringes. A novel apparatus was developed for overcoming this problem; it utilizes continual circulation of gas through a thermostated syringe for sampling, followed by a needleless injection into the chromatograph. Precision and reproducibility well under 0.5% can be obtained in this way. This method was applied to a determination of the solubility of isopentyl acetate in water (2600 ppm) by following the equilibrium vapor response for increasing liquid concentrations. It was also used to determine equilibrium partition coefficients for C1-C5 n-acetates between air and water, over a range of temperatures from 25 to 40 degrees C. PMID:19847988

  13. Aqueous sulfomethylated melamine gel-forming compositions and methods of use

    SciTech Connect

    Meltz, C.N.; Guetzmacher, G.D.; Chang, P.W.

    1989-04-18

    A method is described for the selective modification of the permeability of the strata of a subterranean bydrocarbon-containing reservoir consisting of introducing into a well in, communication with the reservoir; an aqueous gel-forming composition, comprising a 1.0-60.0 weight percent sulfomethylated melamine polymer solution. The solution is prepared with a 1.0 molar equivalent of a malemine, reacted with 3.0-6.7 molar equivalents of formaldehyde or a 2-6 carbon atom containing dialdehyde; 0.25-1.25 molar equivalents of an alkali metal or ammonium salt of surfurous acid; and 0.01-1.5 molar equivalents of a gel-modifying agent.

  14. A simultaneous extraction method for organophosphate, pyrethroid, and neonicotinoid insecticides in aqueous samples.

    PubMed

    de Perre, Chloé; Whiting, Sara A; Lydy, Michael J

    2015-05-01

    A method was developed for the extraction and analysis of 2 organophosphate, 8 pyrethroid, and 5 neonicotinoid insecticides from the same water sample. A salted liquid-liquid extraction (LLE) was optimized with a solid-phase extraction (SPE) step that separated the organophosphates (OPs) and pyrethroids from the neonicotinoids. Factors that were optimized included volume of solvent and amount of salt used in the LLE, homogenization time for the LLE, and type and volume of eluting solvent used for the SPE. The OPs and pyrethroids were quantified using gas chromatography-mass spectrometry, and the neonicotinoids were quantified using liquid chromatography-diode array detector. Results showed that the optimized method was accurate, precise, reproducible, and robust; recoveries in river water spiked with 100 ng L(-1) of each of the insecticides were all between 86 and 114 % with RSDs between 2 and 8 %. The method was also sensitive with method detection limits ranging from 0.1 to 27.2 ng L(-1) depending on compounds and matrices. The optimized method was thus appropriate for the simultaneous extraction of 15 widely applied insecticides from three different classes and was shown to provide valuable information on their environmental fate from field-collected aqueous samples.

  15. Fluid injection for salt water disposal and enhanced oil recovery as a potential problem for the WIPP: Proceedings of a June 1995 workshop and analysis

    SciTech Connect

    Silva, M.K.

    1996-08-01

    The Waste Isolation Pilot Plant (WIPP) is a facility of the U.S. Department of Energy (DOE), designed and constructed for the permanent disposal of transuranic (TRU) defense waste. The repository is sited in the New Mexico portion of the Delaware Basin, at a depth of 655 meters, in the salt beds of the Salado Formation. The WIPP is surrounded by reserves and production of potash, crude oil and natural gas. In selecting a repository site, concerns about extensive oil field development eliminated the Mescalero Plains site in Chaves County and concerns about future waterflooding in nearby oil fields helped eliminate the Alternate II site in Lea County. Ultimately, the Los Medanos site in Eddy County was selected, relying in part on the conclusion that there were no oil reserves at the site. For oil field operations, the problem of water migrating from the injection zone, through other formations such as the Salado, and onto adjacent property has long been recognized. In 1980, the DOE intended to prohibit secondary recovery by waterflooding in one mile buffer surrounding the WIPP Site. However, the DOE relinquished the right to restrict waterflooding based on a natural resources report which maintained that there was a minimal amount of crude oil likely to exist at the WIPP site, hence waterflooding adjacent to the WIPP would be unlikely. This document presents the workshop presentations and analyses for the fluid injection for salt water disposal and enhanced oil recovery utilizing fluid injection and their potential effects on the WIPP facility.

  16. Predictive Sampling of Rare Conformational Events in Aqueous Solution: Designing a Generalized Orthogonal Space Tempering Method

    PubMed Central

    Lv, Chao; Li, Xubin; Wu, Dongsheng; Zheng, Lianqing; Yang, Wei

    2016-01-01

    In aqueous solution, solute conformational transitions are governed by intimate interplays of the fluctuations of solute-solute, solute-water, and water-water interactions. To promote essential fluctuations to enhance sampling, a common strategy is to construct an expanded Hamiltonian through a series of Hamiltonian perturbations, for instance on certain interactions of focus. Due to lack of active sampling of configuration response to perturbation transitions, it is challenging for common expanded Hamiltonian methods to robustly explore solvent mediated rare conformational events. The orthogonal space sampling (OSS) scheme, as exemplified by the orthogonal space random walk and orthogonal space tempering methods, provides a general framework for synchronous acceleration of slow configuration responses. To more effectively sample conformational transitions in aqueous solution, in this work, we devised a generalized orthogonal space tempering (gOST) algorithm. Specifically, in the Hamiltonian perturbation part, a solvent-accessible-surface-area-dependent term is introduced to implicitly perturb near-solute water-water fluctuations; and in the orthogonal space response part, the generalized force order parameter is generalized as a two-dimension order parameter set, in which the solute-solvent and solute-solute components are separately treated. The gOST algorithm is evaluated through a molecular dynamics simulation study on the explicitly-solvated deca-alanine (Ala10) peptide. Based on a fully automated sampling protocol, the gOST simulation enabled repetitive folding and unfolding of the solvated peptide within a single continuous trajectory and allowed for detailed constructions of Ala10 folding/unfolding free energy surfaces. The gOST result reveals that solvent cooperative fluctuations play a pivotal role in Ala10 folding/unfolding transitions. In addition, our assessment analysis suggests that because essential rare events are mainly driven by the compensating

  17. Estimation of octanol/water partition coefficient and aqueous solubility of environmental chemicals using molecular fingerprints and machine learning methods

    EPA Science Inventory

    Octanol/water partition coefficient (logP) and aqueous solubility (logS) are two important parameters in pharmacology and toxicology studies, and experimental measurements are usually time-consuming and expensive. In the present research, novel methods are presented for the estim...

  18. Extraction and demulsification of oil from wheat germ, barley germ, and rice bran using an aqueous enzymatic method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An aqueous enzymatic method was developed to extract oil from wheat germ. The parameters that influence oil yield were investigated, including wheat germ pretreatment, comparison of various industrial enzymes, pH, ratio of wheat germ to water, reaction time and demulsification. Pretreatment at 180ºC...

  19. Application of the SCC-DFTB method to hydroxide water clusters and aqueous hydroxide solutions.

    PubMed

    Choi, Tae Hoon; Liang, Ruibin; Maupin, C Mark; Voth, Gregory A

    2013-05-01

    The self-consistent charge density functional tight binding (SCC-DFTB) method has been applied to hydroxide water clusters and a hydroxide ion in bulk water. To determine the impact of various implementations of SCC-DFTB on the energetics and dynamics of a hydroxide ion in gas phase and condensed phase, the DFTB2, DFTB2-γ(h), DFTB2-γ(h)+gaus, DFTB3-diag, DFTB3-diag+gaus, DFTB3-Full+gaus, and DFTB3-3OB implementations have been tested. Energetic stabilities for small hydroxide clusters, OH(-)(H2O)n, where n = 4-7, are inconsistent with the results calculated with the B3LYP and second order Møller-Plesset (MP2) levels of ab initio theory. The condensed phase simulations, OH(-)(H2O)127, using the DFTB2, DFTB2-γ(h), DFTB2-γ(h)+gaus, DFTB3-diag, DFTB3-diag+gaus, DFTB3-Full+gaus and DFTB3-3OB methods are compared to Car-Parrinello molecular dynamics (CPMD) simulations using the BLYP functional. The SCC-DFTB method including a modified O-H repulsive potential and the third order correction (DFTB3-diag/Full+gaus) is shown to poorly reproduce the CPMD computational results, while the DFTB2 and DFTB2-γ(h) method somewhat more closely describe the structural and dynamical nature of the hydroxide ion in condensed phase. The DFTB3-3OB outperforms the MIO parameter set but is no more accurate than DFTB2. It is also shown that the overcoordinated water molecules lead to an incorrect bulk water density and result in unphysical water void formation. The results presented in this paper point to serious drawbacks for various DFTB extensions and corrections for a hydroxide ion in aqueous environments. PMID:23566052

  20. A New Method for Multicomponent Activity Coefficients of Electrolytes in Aqueous Atmospheric Aerosols

    SciTech Connect

    Zaveri, Rahul A.; Easter, Richard C.; Wexler, Anthony S.

    2005-01-21

    Three-dimensional models of atmospheric inorganic aerosols need an accurate yet computationally efficient parameterization of activity coefficients of various electrolytes in multicomponent aqueous solutions. This paper describes the development and application of a new mixing rule for calculating activity coefficients of electrolytes typically found in atmospheric aerosol systems containing H+, NH4+, Na+, Ca2+ SO42-, HSO4-, NO3-, and Cl- ions. The new mixing rule, called MTEM (Multicomponent Taylor Expansion Model), estimates the mean activity coefficient of an electrolyte in a multicomponent solution based on its values in binary solutions of all the electrolytes present in the mixture at the solution water activity aw, assuming aw is equal to the ambient relative humidity. The aerosol water content is calculated using the Zdanovskii-Stokes-Robinson method. For self-consistency, most of the MTEM and Zdanovskii-Stokes-Robinson parameters are derived using the comprehensive Pitzer-Simonson-Clegg model at 298.15 K. MTEM is evaluated for several multicomponent systems representing various continental and marine aerosols, and is contrasted against the mixing rule of Kusik and Meissner and the newer approach of Metzger et al. [2002]. Predictions of MTEM are found to be generally within a factor of 0.8 to 1.25 of the comprehensive Pitzer-Simonson-Clegg model, and are shown to be significantly more accurate than predictions of the other two methods. MTEM also yields a non-iterative solution of the bisulfate ion dissociation in sulfate-rich systems – a major computational advantage over other iterative methods. CPU time requirements of MTEM relative to other methods for sulfate-poor and sulfate-rich systems are also discussed.

  1. An In Situ Method for Sizing Insoluble Residues in Precipitation and Other Aqueous Samples

    PubMed Central

    Axson, Jessica L.; Creamean, Jessie M.; Bondy, Amy L.; Capracotta, Sonja S.; Warner, Katy Y.; Ault, Andrew P.

    2015-01-01

    Particles are frequently incorporated into clouds or precipitation, influencing climate by acting as cloud condensation or ice nuclei, taking up coatings during cloud processing, and removing species through wet deposition. Many of these particles, particularly ice nuclei, can remain suspended within cloud droplets/crystals as insoluble residues. While previous studies have measured the soluble or bulk mass of species within clouds and precipitation, no studies to date have determined the number concentration and size distribution of insoluble residues in precipitation or cloud water using in situ methods. Herein, for the first time we demonstrate that Nanoparticle Tracking Analysis (NTA) is a powerful in situ method for determining the total number concentration, number size distribution, and surface area distribution of insoluble residues in precipitation, both of rain and melted snow. The method uses 500 μL or less of liquid sample and does not require sample modification. Number concentrations for the insoluble residues in aqueous precipitation samples ranged from 2.0–3.0(±0.3)×108 particles cm−3, while surface area ranged from 1.8(±0.7)–3.2(±1.0)×107 μm2 cm−3. Number size distributions peaked between 133–150 nm, with both single and multi-modal character, while surface area distributions peaked between 173–270 nm. Comparison with electron microscopy of particles up to 10 μm show that, by number, > 97% residues are <1 μm in diameter, the upper limit of the NTA. The range of concentration and distribution properties indicates that insoluble residue properties vary with ambient aerosol concentrations, cloud microphysics, and meteorological dynamics. NTA has great potential for studying the role that insoluble residues play in critical atmospheric processes. PMID:25705069

  2. Evaluation of extraction methods for quantification of aqueous fullerenes in urine

    PubMed Central

    Pycke, Benny F. G.; Herckes, Pierre; Westerhoff, Paul; Halden, Rolf U.

    2013-01-01

    There is a growing concern about the human and environmental health effects of fullerenes (e.g., C60) due to their increasing application in research, medicine, and industry. Toxicological and pharmacokinetic research requires standard methods for extraction and detection of fullerenes from biological matrices such as urine. The present study validates the use of liquid-liquid extraction (LLE) and solid-phase extraction (SPE) methods in conjunction with liquid chromatography–mass spectrometry (LC–MS) for the quantitative determination of C60 in human and synthetic urine as compared with ultrapure water. Glacial acetic acid, which is necessary to prevent emulsions during LLE, inhibited C60 detection by LC–MS, but this could be mitigated with evaporation. Aqueous C60 aggregates (nC60) were spiked at 180 µg/L into the components of a synthetic urine recipe to determine their individual impacts on extraction and detection. Urea, creatinine, and a complex protein (i.e., gelatin) were found to impair SPE, leading to a low recovery rate of 43±4% for C60 spiked into human urine. In contrast, C60 was consistently recovered from synthetic matrices using LLE, and recovery in human urine was 80±6%. These results suggest that LLE combined with LC–MS is suitable for studying the clearance of fullerenes from the body. LLE is a robust technique that holds promise for extracting C60 from other complex biological matrices (e.g., blood, sweat, amniotic fluid) in toxicological studies, enabling a better understanding of the behavior of fullerenes in human and animal systems and facilitating a more comprehensive risk evaluation of fullerenes. PMID:21153587

  3. Revised Earthquake Catalog and Relocated Hypocenters Near Fluid Injection Wells and the Waste Isolation Pilot Plant (WIPP) in Southeastern New Mexico

    NASA Astrophysics Data System (ADS)

    Edel, S.; Bilek, S. L.; Garcia, K.

    2014-12-01

    Induced seismicity is a class of crustal earthquakes resulting from human activities such as surface and underground mining, impoundment of reservoirs, withdrawal of fluids and gas from the subsurface, and injection of fluids into underground cavities. Within the Permian basin in southeastern New Mexico lies an active area of oil and gas production, as well as the Waste Isolation Pilot Plant (WIPP), a geologic nuclear waste repository located just east of Carlsbad, NM. Small magnitude earthquakes have been recognized in the area for many years, recorded by a network of short period vertical component seismometers operated by New Mexico Tech. However, for robust comparisons between the seismicity patterns and the injection well locations and rates, improved locations and a more complete catalog over time are necessary. We present results of earthquake relocations for this area by using data from the 3-component broadband EarthScope Flexible Array SIEDCAR experiment that operated in the area between 2008-2011. Relocated event locations tighten into a small cluster of ~38 km2, approximately 10 km from the nearest injection wells. The majority of events occurred at 10-12 km depth, given depth residuals of 1.7-3.6 km. We also present a newly developed more complete catalog of events from this area by using a waveform cross-correlation algorithm and the relocated events as templates. This allows us to detect smaller magnitude events that were previously undetected with the short period network data. The updated earthquake catalog is compared with geologic maps and cross sections to identify possible fault locations. The catalog is also compared with available well data on fluid injection and production. Our preliminary results suggest no obvious connection between seismic moment release, fluid injection, or production given the available monthly industry data. We do see evidence in the geologic and well data of previously unidentified faults in the area.

  4. [Value of gentamycin concentration in aqueous humor of a rabbit's eye depending on the method of application. Summary of a doctoral thesis].

    PubMed

    Philips, R H

    1992-10-01

    Pharmacokinetics of gentamycin in the primary and secondary rabbit's aqueous was examined by using a new experimental method of subconjunctival application (without breaking the continuity of the conjunctiva). It was established that after subconjunctival application one cannot obtain any therapeutical concentrations in the primary or secondary aqueous. Presented are conditions which have to be fulfilled to obtain a therapeutical concentration of gentamycin in the secondary aqueous. PMID:1306533

  5. Method Of Dispensing Microdoses Of A Aqueous Solutions Of S Ubstances Onto A Carrier And A Device For Carrying Out Said Method

    DOEpatents

    Ershov, Gennady Moiseevich; Kirillov, Eugenii Vladislavovich; Mirzabekov, Andrei Darievich

    1999-10-05

    A method and a device for dispensing microdoses of aqueous solutions are provided, whereby the substance is transferred by the free surface end of a rodlike transferring element; the temperature of the transferring element is maintained at essentially the dew point of the ambient air during the transfer. The device may comprise a plate-like base to which are affixed a plurality of rods; the unfixed butt ends of the rods are coplanar. The device further comprises a means for maintaining the temperature of the unfixed butt ends of the rods essentially equal to the dew point of the ambient air during transfer of the aqueous substance

  6. Analysis of. gamma. -radiolysis products of aqueous solutions of esters of aliphatic amino acids by the PMR method

    SciTech Connect

    Panin, V.I.; Sidorov, P.S.; Usatyi, A.F.

    1987-09-01

    The ..gamma..-radiolysis of aqueous solutions of methyl esters of aliphatic amino acids and peptides was investigated by the method of nuclear (proton) magnetic resonance (PMR). The resonance lines appearing in the PMR spectra of the irradiated systems were identified, and a conclusion was drawn about the molecular structure of the radiolysis products. The kinetics of the accumulation of radiolysis products was studied, and the values of their radiation yields were estimated.

  7. Development of a group contribution method to predict aqueous phase hydroxyl radical (HO*) reaction rate constants.

    PubMed

    Minakata, Daisuke; Li, Ke; Westerhoff, Paul; Crittenden, John

    2009-08-15

    The hydroxyl radical (HO*) is a strong oxidant that reacts with electron-rich sites of organic compounds and initiates complex chain mechanisms. In order to help understand the reaction mechanisms, a rule-based model was previously developed to predict the reaction pathways. For a kinetic model, there is a need to develop a rate constant estimator that predicts the rate constants for a variety of organic compounds. In this study, a group contribution method (GCM) is developed to predict the aqueous phase HO* rate constants for the following reaction mechanisms: (1) H-atom abstraction, (2) HO* addition to alkenes, (3) HO* addition to aromatic compounds, and (4) HO* interaction with sulfur (S)-, nitrogen (N)-, or phosphorus (P)-atom-containing compounds. The GCM hypothesizes that an observed experimental rate constant for a given organic compound is the combined rate of all elementary reactions involving HO*, which can be estimated using the Arrhenius activation energy, E(a), and temperature. Each E(a) for those elementary reactions can be comprised of two parts: (1) a base part that includes a reactive bond in each reaction mechanism and (2) contributions from its neighboring functional groups. The GCM includes 66 group rate constants and 80 group contribution factors, which characterize each HO* reaction mechanism with steric effects of the chemical structure groups and impacts of the neighboring functional groups, respectively. Literature-reported experimental HO* rate constants for 310 and 124 compounds were used for calibration and prediction, respectively. The genetic algorithms were used to determine the group rate constants and group contribution factors. The group contribution factors for H-atom abstraction and HO* addition to the aromatic compounds were found to linearly correlate with the Taft constants, sigma*, and electrophilic substituent parameters, sigma+, respectively. The best calibrations for 83% (257 rate constants) and predictions for 62% (77

  8. Insights into the removal of terbuthylazine from aqueous solution by several treatment methods.

    PubMed

    Álvarez, Pedro M; Quiñones, Diego H; Terrones, Isidro; Rey, Ana; Beltrán, Fernando J

    2016-07-01

    This paper reports the removal of the s-triazine herbicide terbuthylazine (TBA) from aqueous solution by various treatment methods including adsorption onto activated carbon (AC) and multiwalled carbon nanotubes (MWCNT), UV254 photolysis, UV254/H2O2, single ozonation, O3/H2O2, catalytic ozonation (AC, MWCNT and TiO2 as catalysts) and some solar driven processes such as TiO2 photocatalytic oxidation and photo-ozonation. TBA was adsorbed onto AC and MWCNT following a pseudo-second order kinetics and Freundlich isotherm. Rapid small scale column tests showed that TBA could be removed from solution by adsorption onto AC better than atrazine. The UV254/H2O2 treatment resulted in excellent removal of TBA primarily due to the oxidation capability of hydroxyl radicals (kHO = 3.310(9) M(-1) s(-1)) generated from H2O2 photolysis. As the H2O2 initial concentration was increased from 5 to 50 mg L(-1) the HO exposure per UV fluence (RHO,UV) increased, making the process more efficient. Single ozonation also allowed complete removal of the herbicide though the process was slow (kO3=15.4 M(-1) s(-1) at pH > 4). The ozonation process could be greatly accelerated by the enhanced generation of HO through O3/H2O2 and O3/AC processes, which also led to more efficient processes in terms of ozone utilization. Commercial TiO2 (TiO2-P25) and lab prepared anatase TiO2 (TiO2-cat) nanoparticles catalyzed the removal of TBA by solar photocatalysis. In contrast, a lab prepared MWCNT-TiO2 composite was not useful as catalyst in solar photo-oxidation processes because of the HO scavenging nature of the MWCNT used as support. A mechanism for TBA degradation by O3 and HO has been suggested after TBA degradation intermediates identification.

  9. Insights into the removal of terbuthylazine from aqueous solution by several treatment methods.

    PubMed

    Álvarez, Pedro M; Quiñones, Diego H; Terrones, Isidro; Rey, Ana; Beltrán, Fernando J

    2016-07-01

    This paper reports the removal of the s-triazine herbicide terbuthylazine (TBA) from aqueous solution by various treatment methods including adsorption onto activated carbon (AC) and multiwalled carbon nanotubes (MWCNT), UV254 photolysis, UV254/H2O2, single ozonation, O3/H2O2, catalytic ozonation (AC, MWCNT and TiO2 as catalysts) and some solar driven processes such as TiO2 photocatalytic oxidation and photo-ozonation. TBA was adsorbed onto AC and MWCNT following a pseudo-second order kinetics and Freundlich isotherm. Rapid small scale column tests showed that TBA could be removed from solution by adsorption onto AC better than atrazine. The UV254/H2O2 treatment resulted in excellent removal of TBA primarily due to the oxidation capability of hydroxyl radicals (kHO = 3.310(9) M(-1) s(-1)) generated from H2O2 photolysis. As the H2O2 initial concentration was increased from 5 to 50 mg L(-1) the HO exposure per UV fluence (RHO,UV) increased, making the process more efficient. Single ozonation also allowed complete removal of the herbicide though the process was slow (kO3=15.4 M(-1) s(-1) at pH > 4). The ozonation process could be greatly accelerated by the enhanced generation of HO through O3/H2O2 and O3/AC processes, which also led to more efficient processes in terms of ozone utilization. Commercial TiO2 (TiO2-P25) and lab prepared anatase TiO2 (TiO2-cat) nanoparticles catalyzed the removal of TBA by solar photocatalysis. In contrast, a lab prepared MWCNT-TiO2 composite was not useful as catalyst in solar photo-oxidation processes because of the HO scavenging nature of the MWCNT used as support. A mechanism for TBA degradation by O3 and HO has been suggested after TBA degradation intermediates identification. PMID:27115726

  10. Evaluation of Eye Irritation Potential of Aqueous Leaf Extract of Achyranthes aspera by In Vitro and In Vivo Method

    PubMed Central

    Rajpal Deshmukh, Gajanan; Hema Kumar, Kuntrapakam; Suresh Reddy, Poojari Venkata; Srinivasa Rao, Boddapati; Venkata Satish Kumar, Chirumamilla

    2012-01-01

    The present paper is an attempt to investigate the eye irritation potential of aqueous leaf extract of Achyranthes aspera by in vitro, Hen's Egg Chorioallantoic Membrane Test (HET-CAM) and in vivo acute eye irritation test in rabbits. The irritation score (IS) obtained after treatment of the extract on HET-CAM is 0.07 and that of in rabbits is 0.55, Which does not comes under either category 1 or 2 as per the harmonized integrated classification system. The aqueous extract of Achyranthes aspera showed no eye irritation properties both in vitro and in vivo methods when compared with negative control whereas positive controls showed eye irritation potential. PMID:23724295

  11. Tuning the size and configuration of nanocarbon microcapsules: aqueous method using optical tweezers

    PubMed Central

    Frusawa, Hiroshi; Matsumoto, Youei

    2014-01-01

    To date, optical manipulation techniques for aqueous dispersions have been developed that deposit and/or transport nanoparticles not only for fundamental studies of colloidal dynamics, but also for either creating photonic devices or allowing accurate control of liquids on micron scales. Here, we report that optical tweezers (OT) system is able to direct three-dimensional assembly of graphene, graphite, and carbon nanotubes (CNT) into microcapsules of hollow spheres. The OT technique facilitates both to visualize the elasticity of a CNT microcapsule and to arrange a triplet of identical graphene microcapsules in aqueous media. Furthermore, the similarity of swelling courses has been found over a range of experimental parameters such as nanocarbon species, the power of the incident light, and the suspension density. Thanks to the universality in evolutions of rescaled capsule size, we can precisely control the size of various nanocarbon microcapsules by adjusting the duration time of laser emission. PMID:24509866

  12. Tuning the size and configuration of nanocarbon microcapsules: aqueous method using optical tweezers

    NASA Astrophysics Data System (ADS)

    Frusawa, Hiroshi; Matsumoto, Youei

    2014-02-01

    To date, optical manipulation techniques for aqueous dispersions have been developed that deposit and/or transport nanoparticles not only for fundamental studies of colloidal dynamics, but also for either creating photonic devices or allowing accurate control of liquids on micron scales. Here, we report that optical tweezers (OT) system is able to direct three-dimensional assembly of graphene, graphite, and carbon nanotubes (CNT) into microcapsules of hollow spheres. The OT technique facilitates both to visualize the elasticity of a CNT microcapsule and to arrange a triplet of identical graphene microcapsules in aqueous media. Furthermore, the similarity of swelling courses has been found over a range of experimental parameters such as nanocarbon species, the power of the incident light, and the suspension density. Thanks to the universality in evolutions of rescaled capsule size, we can precisely control the size of various nanocarbon microcapsules by adjusting the duration time of laser emission.

  13. Method for gettering organic, inorganic and elemental iodine in aqueous solutions

    DOEpatents

    Beahm, Edward C.; Shockley, William E.

    1990-07-03

    A process for the removal of iodine from aqueous solutions, particularly the trapping of radioactive iodine to mitigate damage resulting from accidents or spills associated with nuclear reactors, by exposing the solution to well dispersed silver carbonate which reacts with the iodine and iodides, thereby gettering iodine and iodine compounds from solution. The iodine is not only removed from solution but also from the contiguous vapor.

  14. Method for gettering organic, inorganic and elemental iodine in aqueous solutions

    DOEpatents

    Beahm, Edward C.; Shockley, William E.

    1990-01-01

    A process for the removal of iodine from aqueous solutions, particularly the trapping of radioactive iodine to mitigate damage resulting from accidents or spills associated with nuclear reactors, by exposing the solution to well dispersed silver carbonate which reacts with the iodine and iodides, thereby gettering iodine and iodine compounds from solution. The iodine is not only removed from solution but also from the contiguous vapor.

  15. Development of a Rapid, Nondestructive Method to Measure Aqueous Carbonate in High Salinity Brines Using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    McGraw, L.; Phillips-Lander, C. M.; Elwood Madden, A. S.; Parnell, S.; Elwood Madden, M.

    2015-12-01

    Traditional methods of quantitative analysis are often ill-suited to determining the bulk chemistry of high salinity brines due to their corrosive and clogging properties. Such methods are also often difficult to apply remotely in planetary environments. However, Raman spectroscopy can be used remotely without physical contact with the fluid and is not affected by many ionic brines. Developing methods to study aqueous carbonates is vital to future study of brines on Mars and other planetary bodies, as they can reveal important information about modern and ancient near-surface aqueous processes. Both sodium carbonate standards and unknown samples from carbonate mineral dissolution experiments in high salinity brines were analyzed using a 532 nm laser coupled to an inVia Renishaw spectrometer to collect carbonate spectra from near-saturated sodium chloride and sodium sulfate brines. A calibration curve was determined by collecting spectra from solutions of known carbonate concentrations mixed with a pH 13 buffer and a near-saturated NaCl or Na2SO4 brine matrix. The spectra were processed and curve fitted to determine the height ratio of the carbonate peak at 1066 cm-1 to the 1640 cm-1 water peak. The calibration curve determined using the standards was then applied to the experimental data after accounting for dilutions. Concentrations determined based on Raman spectra were compared against traditional acid titration measurements. We found that the two techniques vary by less than one order of magnitude. Further work is ongoing to verify the method and apply similar techniques to measure aqueous carbonate concentrations in other high salinity brines.Traditional methods of quantitative analysis are often ill-suited to determining the bulk chemistry of high salinity brines due to their corrosive and clogging properties. Such methods are also often difficult to apply remotely in planetary environments. However, Raman spectroscopy can be used remotely without physical

  16. Effects of long-term fluid injection on induced seismicity parameters and maximum magnitude in northwestern part of The Geysers geothermal field

    NASA Astrophysics Data System (ADS)

    Kwiatek, Grzegorz; Martínez-Garzón, Patricia; Dresen, Georg; Bohnhoff, Marco; Sone, Hiroki; Hartline, Craig

    2015-10-01

    The long-term temporal and spatial changes in statistical, source, and stress characteristics of one cluster of induced seismicity recorded at The Geysers geothermal field (U.S.) are analyzed in relation to the field operations, fluid migration, and constraints on the maximum likely magnitude. Two injection wells, Prati-9 and Prati-29, located in the northwestern part of the field and their associated seismicity composed of 1776 events recorded throughout a 7 year period were analyzed. The seismicity catalog was relocated, and the source characteristics including focal mechanisms and static source parameters were refined using first-motion polarity, spectral fitting, and mesh spectral ratio analysis techniques. The source characteristics together with statistical parameters (b value) and cluster dynamics were used to investigate and understand the details of fluid migration scheme in the vicinity of injection wells. The observed temporal, spatial, and source characteristics were clearly attributed to fluid injection and fluid migration toward greater depths, involving increasing pore pressure in the reservoir. The seasonal changes of injection rates were found to directly impact the shape and spatial extent of the seismic cloud. A tendency of larger seismic events to occur closer to injection wells and a correlation between the spatial extent of the seismic cloud and source sizes of the largest events was observed suggesting geometrical constraints on the maximum likely magnitude and its correlation to the average injection rate and volume of fluids present in the reservoir.

  17. Method for removal of metal atoms from aqueous solution using suspended plant cells

    DOEpatents

    Jackson, Paul J.; Torres, deceased, Agapito P.; Delhaize, Emmanuel

    1992-01-01

    The use of plant suspension cultures to remove ionic metallic species and TNT-based explosives and their oxidation products from aqueous solution is described. Several plant strains were investigated including D. innoxia, Citrus citrus, and Black Mexican Sweet Corn. All showed significant ability to remove metal ions. Ions removed to sub-ppm levels include barium, iron, and plutonium. D. innoxia cells growing in media containing weapons effluent contaminated with Ba.sup.2+ also remove TNT, other explosives and oxidation products thereof from solution. The use of dead, dehydrated cells were also found to be of use in treating waste directly.

  18. Method for removal of explosives from aqueous solution using suspended plant cells

    DOEpatents

    Jackson, Paul J.; Torres, deceased, Agapito P.; Delhaize, Emmanuel

    1994-01-01

    The use of plant suspension cultures to remove ionic metallic species and TNT-based explosives and their oxidation products from aqueous solution is described. Several plant strains were investigated including D. innoxia, Citrus citrus, and Black Mexican Sweet Corn. All showed significant ability to remove metal ions. Ions removed to sub-ppm levels include barium, iron, and plutonium. D. innoxia cells growing in media containing weapons effluent contaminated with Ba.sup.2+ also remove TNT, other explosives and oxidation products thereof from solution. The use of dead, dehydrated cells was also found to be of use in treating waste directly.

  19. METHOD OF RECOVERING PLUTONIUM VALUES FROM AQUEOUS SOLUTIONS BY CARRIER PRECIPITATION

    DOEpatents

    James, R.A.; Thompson, S.G.

    1959-11-01

    A process is presented for pretreating aqueous nitric acid- plutonium solutions containing a small quantity of hydrazine that has formed as a decomposition product during the dissolution of neutron-bombarded uranium in nitric acid and that impairs the precipitation of plutonium on bismuth phosphate. The solution is digested with alkali metal dichromate or potassium permanganate at between 75 and 100 deg C; sulfuric acid at approximately 75 deg C and sodium nitrate, oxaiic acid plus manganous nitrate, or hydroxylamine are added to the solution to secure the plutonium in the tetravalent state and make it suitable for precipitation on BiPO/sub 4/.

  20. Identification of aqueous pollen extracts using surface enhanced Raman scattering (SERS) and pattern recognition methods.

    PubMed

    Seifert, Stephan; Merk, Virginia; Kneipp, Janina

    2016-01-01

    Aqueous pollen extracts of varying taxonomic relations were analyzed with surface enhanced Raman scattering (SERS) by using gold nanoparticles in aqueous suspensions as SERS substrate. This enables a selective vibrational characterization of the pollen water soluble fraction (mostly cellular components) devoid of the spectral contributions from the insoluble sporopollenin outer layer. The spectra of the pollen extracts are species-specific, and the chemical fingerprints can be exploited to achieve a classification that can distinguish between different species of the same genus. In the simple experimental procedure, several thousands of spectra per species are generated. Using an artificial neural network (ANN), it is demonstrated that analysis of the intrinsic biochemical information of the pollen cells in the SERS data enables the identification of pollen from different plant species at high accuracy. The ANN extracts the taxonomically-relevant information from the data in spite of high intra-species spectral variation caused by signal fluctuations and preparation specifics. The results show that SERS can be used for the reliable characterization and identification of pollen samples. They have implications for improved investigation of pollen physiology and for allergy warning.

  1. Method for recovering aluminum fluoride from fluorine-containing aqueous aluminum nitrate solutions

    SciTech Connect

    Ishimi, H.; Shimauchi, H.; Tanaka, C.

    1983-02-22

    In a process for converting UF/sub 6/ into UO/sub 2/, the UF/sub 6/ is brought into contact with an aqueous aluminum nitrate solution. The resultant product is solvent extracted with tributyl phosphate to remove uranyl nitrate. The raffinate has a fluorine/aluminum (F/Al) weight ratio within the range of from about 0.5 to about a sufficient quantity of hydrofluoric acid is added to T raffinate to minimize the solubility of aluminum fluoride (AlF/sub 3/) therein and thereby maximize the precipitation potential of AlF/sub 3/. Generally this occurs when sufficient hydrofluoric acid has been added to cause the F/Al weight ratio to be within the range of from about 1.8 to about 2.2. As a result of this treatment, the raffinate is divided into an uranium-containing aqueous solution and an AlF/sub 3/ precipitate which contains substantially no uranium.

  2. Graphical methods for representing form and stability of aqueous metal ions

    USGS Publications Warehouse

    Hem, J.D.

    1972-01-01

    The equilibrium distributions of solute species of aluminum at 25??C and one atmosphere pressure are shown graphically in systems containing fluoride, as functions of the total dissolved aluminum and fluoride. The predominant form of complex and degree of complexing are also shown graphically as functions of pH and fluoride activity. The graphs are based on the simultaneous solution of the equations representing nine complexing equilibria and three stoichiometric summarizations, using a fixed value of ionic strength equal to 0.1. Solubility relationships for aluminum hydroxide and cryolite also are shown graphically, using the same coordinates and additional equilibria. By overlaying an appropriate species distribution graph with a solubility graph a relatively complete summary of chemical relationships in an aqueous aluminum system can be obtained. Although this type of model has important limitations, it can accommodate enough variables simultaneously to have practical value and similar procedures could be used for other elements and systems of interest in low-temperature aqueous geochemistry. ?? 1972.

  3. Review of methods and measurements of selected hydrophobic organic contaminant aqueous solubilities, vapor pressures, and air-water partition coefficients

    SciTech Connect

    Bamford, H.A.; Baker, J.E.; Poster, D.L.

    1998-03-01

    Aqueous solubilities, vapor pressures, and Henry`s law constants for a wide range of organic contaminants of environmental interest are presented. Specifically, a discussion of methods used to measure these physical constants and resulting measurements are provided in an effort to examine the scope of physical constants reported in the scientific literature. Physical constants reviewed include those for 40 PAHs, 14 chlorinated aliphatics, 149 PCBs, 12 chlorinated benzenes, 16 dioxins, 63 furans, and 29 agrochemicals (a total of 323 compounds) and overall a total of 1,605 values are listed.

  4. Development of an analytical method for the determination of organic compounds in fossil-fuel aqueous leachates

    SciTech Connect

    White, C.M.; Avery, M.; Blanton, W.; Hilpert, L.; Jackson, L.; Junk, G.; Maskarinec, M.; Paule, R.C.; Raphaelian, L.; Richard, J.

    1983-10-01

    An analytical method has been developed for analysis of organic compounds in aqueous leachates of fossil fuel solid wastes. The method has been evaluated using two synthetic leachates as well as bulk and small-scale leachates of SRC-II vacuum still bottoms at the participating laboratories. Under the conditions of these tests, the method worked well for most analytes; however, n-hexanoic acid, 4-aminobiphenyl, 1,4-naphtoquinone, and 1-nephthylamine were not determined accurately or precisely by the method. Other analytes of interest are benzanthracene, o-cresol, phenanthrene, carbazole, naphthalene, phenol, n-tetradecane, 2-naphthol, dibenzothiophene, quinoline, acenaphthylene, 2-picoline, fluoranthrene, 2,3,4,5-tetrachlorobiphenyl (standard), 2-fluorophenol (standard), n-octacosane (standard), and azulene (standard). 7 references, 22 figures, 26 tables.

  5. A method of calculating quartz solubilities in aqueous sodium chloride solutions

    USGS Publications Warehouse

    Fournier, R.O.

    1983-01-01

    The aqueous silica species that form when quartz dissolves in water or saline solutions are hydrated. Therefore, the amount of quartz that will dissolve at a given temperature is influenced by the prevailing activity of water. Using a standard state in which there are 1,000 g of water (55.51 moles) per 1,000 cm3 of solution allows activity of water in a NaCl solution at high temperature to be closely approximated by the effective density of water, pe, in that solution, i.e. the product of the density of the NaCl solution times the weight fraction of water in the solution, corrected for the amount of water strongly bound to aqueous silica and Na+ as water of hydration. Generally, the hydration of water correction is negligible. The solubility of quartz in pure water is well known over a large temperature-pressure range. An empirical formula expresses that solubility in terms of temperature and density of water and thus takes care of activity coefficient and pressure-effect terms. Solubilities of quartz in NaCl solutions can be calculated by using that equation and substituting pe, for the density of pure water. Calculated and experimentally determined quartz solubilities in NaCl solutions show excellent agreement when the experiments were carried out in non-reactive platinum, gold, or gold plus titanium containers. Reactive metal containers generally yield dissolved silica concentrations higher than calculated, probably because of the formation of metal chlorides plus NaOH and H2. In the absence of NaOH there appears to be no detectable silica complexing in NaCl solutions, and the variation in quartz solubility with NaCl concentration at constant temperature can be accounted for entirely by variations in the activity of water. The average hydration number per molecule of dissolved SiO2 in liquid water and NaCl solutions decreases from about 2.4 at 200??C to about 2.1 at 350??C. This suggests that H4SiO4 may be the dominant aqueous silica species at 350??C, but other

  6. Characterisation and optimisation of a method for the detection and quantification of atmospherically relevant carbonyl compounds in aqueous medium

    NASA Astrophysics Data System (ADS)

    Rodigast, M.; Mutzel, A.; Iinuma, Y.; Haferkorn, S.; Herrmann, H.

    2015-01-01

    Carbonyl compounds are ubiquitous in the atmosphere and either emitted primarily from anthropogenic and biogenic sources or they are produced secondarily from the oxidation of volatile organic compounds (VOC). Despite a number of studies about the quantification of carbonyl compounds a comprehensive description of optimised methods is scarce for the quantification of atmospherically relevant carbonyl compounds. Thus a method was systematically characterised and improved to quantify carbonyl compounds. Quantification with the present method can be carried out for each carbonyl compound sampled in the aqueous phase regardless of their source. The method optimisation was conducted for seven atmospherically relevant carbonyl compounds including acrolein, benzaldehyde, glyoxal, methyl glyoxal, methacrolein, methyl vinyl ketone and 2,3-butanedione. O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was used as derivatisation reagent and the formed oximes were detected by gas chromatography/mass spectrometry (GC/MS). The main advantage of the improved method presented in this study is the low detection limit in the range of 0.01 and 0.17 μmol L-1 depending on carbonyl compounds. Furthermore best results were found for extraction with dichloromethane for 30 min followed by derivatisation with PFBHA for 24 h with 0.43 mg mL-1 PFBHA at a pH value of 3. The optimised method was evaluated in the present study by the OH radical initiated oxidation of 3-methylbutanone in the aqueous phase. Methyl glyoxal and 2,3-butanedione were found to be oxidation products in the samples with a yield of 2% for methyl glyoxal and 14% for 2,3-butanedione.

  7. Aseismic and seismic slip induced by fluid injection from poroelastic and rate-state friction modeling with application to the Fox Creek, Alberta, 2013-2015 earthquake sequence

    NASA Astrophysics Data System (ADS)

    Liu, Yajing; Deng, Kai; Clerc, Fiona; Castro, Andres; Harrington, Rebecca

    2016-04-01

    Stress change and pore pressure evolution caused by fluid injection has been postulated as a key factor for inducing both moderate-size earthquakes and aseismic slip on pre-existing faults. In this study, we have developed a numerical model that simulates aseismic and seismic slip in a rate-and-state friction framework with stress perturbations provided by a poroelastic model for multistage hydraulic fracturing scenarios. The coupling of external stress changes and their spatiotemporal variation to fault frictional strength in a single computational procedure provides a quantitative understanding of the source processes (i.e., slip rate, triggering threshold) of the spectrum of induced slip modes. We apply the physics-based fault slip model to the induced earthquake sequences near Fox Creek, Alberta, in the western Canada sedimentary basin, where two earthquakes of ML4.4 (2015/01/23) and Mw4.6 (2015/06/13) were potentially induced by nearby hydraulic fracturing activity. In particular, we use the relocated December 2013 seismicity sequence to approximate the fault orientation, and find the seismicity migration spatiotemporally correlate with the positive Coulomb stress changes calculated by the poroelastic model. When the poroelastic stress changes are introduced to the rate-state friction model as external perturbations, we find that the fault, previously undergoing aseismic slip, can be perturbed into seismic rupturing even after hydraulic fracturing has stopped but stress perturbations continues to evolve in the medium (Scenario 1). In an end-member case (Scenario 2) where stress perturbations are instantaneously returned to zero at shut-in, we observe aseismic slip; all other conditions unchanged from Scenario 1. Seismic slip is also more readily induced by larger stress perturbations. Our preliminary results thus suggest the design of flow-back strategy, either passively evolving in the medium or actively dropping to pre-perturbation level, is essential to

  8. Quantifying water diffusion in high-viscosity and glassy aqueous solutions using a Raman isotope tracer method

    NASA Astrophysics Data System (ADS)

    Price, H. C.; Murray, B. J.; Mattsson, J.; O'Sullivan, D.; Wilson, T. W.; Baustian, K. J.; Benning, L. G.

    2013-11-01

    Recent research suggests that under certain temperature and relative humidity conditions atmospheric aerosol may be present in the form of a glassy solid. In order to understand the impacts that this may have on aerosol-cloud interactions and atmospheric chemistry, knowledge of water diffusion within such aerosol particles is required. Here, a method is described in which Raman spectroscopy is used to observe D2O diffusion in high-viscosity aqueous solutions, enabling a quantitative assessment of water diffusion coefficients, Dwater, as a function of relative humidity. Results for sucrose solutions compare well with literature data at 23.5 ± 0.3 °C, and demonstrate that water diffusion is slow (Dwater~5 ×10-17m2s-1), but not arrested, just below the glass transition. Room temperature water diffusion coefficients are also presented for aqueous levoglucosan and an aqueous mixture of raffinose, dicarboxylic acids and ammonium sulphate: at low humidity, diffusion is retarded but still occurs on millisecond to second timescales in atmospherically relevant-sized particles. The effect of gel formation on diffusion in magnesium sulfate solutions is shown to be markedly different from the gradual decrease in diffusion coefficients of highly viscous liquids. We show that using the Stokes-Einstein equation to determine diffusion timescales from viscosity leads to values which are more than five orders of magnitude too big, which emphasises the need to make measurements of diffusion coefficients. In addition, comparison of bounce fraction data for levoglucosan with measured diffusion data reveals that even when particles bounce the equilibration timescales for water are a fraction of a second for a 100 nm particle. This suggests a high bounce fraction does not necessarily indicate retarded water diffusion.

  9. Quantifying water diffusion in high-viscosity and glassy aqueous solutions using a Raman isotope tracer method

    NASA Astrophysics Data System (ADS)

    Price, H. C.; Murray, B. J.; Mattsson, J.; O'Sullivan, D.; Wilson, T. W.; Baustian, K. J.; Benning, L. G.

    2014-04-01

    Recent research suggests that under certain temperature and relative humidity conditions atmospheric aerosol may be present in the form of a glassy solid. In order to understand the impacts that this may have on aerosol-cloud interactions and atmospheric chemistry, knowledge of water diffusion within such aerosol particles is required. Here, a method is described in which Raman spectroscopy is used to observe D2O diffusion in high-viscosity aqueous solutions, enabling a quantitative assessment of water diffusion coefficients, Dwater, as a function of relative humidity. Results for sucrose solutions compare well with literature data at 23.5 ± 0.3 °C, and demonstrate that water diffusion is slow (Dwater ~5 × 10-17 m2 s-1), but not arrested, just below the glass transition at a water activity of 0.2. Room temperature water diffusion coefficients are also presented for aqueous levoglucosan and an aqueous mixture of raffinose, dicarboxylic acids and ammonium sulphate: at low humidity, diffusion is retarded but still occurs on millisecond to second timescales in atmospherically relevant-sized particles. The effect of gel formation on diffusion in magnesium sulfate solutions is shown to be markedly different from the gradual decrease in diffusion coefficients of highly viscous liquids. We show that using the Stokes-Einstein equation to determine diffusion timescales from viscosity leads to values which are more than 5 orders of magnitude too big, which emphasises the need to make measurements of diffusion coefficients. In addition, comparison of bounce fraction data for levoglucosan with measured diffusion data reveals that even when particles bounce the diffusion timescales for water are a fraction of a second for a 100 nm particle. This suggests a high bounce fraction does not necessarily indicate retarded water diffusion.

  10. Vapor diffusion method: Dependence of polymorphs and morphologies of calcium carbonate crystals on the depth of an aqueous solution

    NASA Astrophysics Data System (ADS)

    Liu, Qing; Wang, Hai-Shui; Zeng, Qiang

    2016-09-01

    The polymorph control of calcium carbonate by the vapor diffusion method is still a challenging issue because the resultant crystal polymorphs and morphologies highly depend on the experimental setup. In this communication, we demonstrated that the concentration gradients accompanied by the vapor diffusion method (ammonia concentration, pH and the ratio of CO32- to Ca2+ are changed with the solution depth and with time) are probably the main reasons to significantly affect the formation of crystal polymorphs. Raman, SEM and XRD data showed that calcite and vaterite crystals were preferred to nucleate and grow in the upper or the lower areas of aqueous solution respectively. The above results can be explained by the gradient effect.

  11. An aqueous preoxidation method for monolithic perovskite electrocatalysts with enhanced water oxidation performance

    PubMed Central

    Li, Bo-Quan; Tang, Cheng; Wang, Hao-Fan; Zhu, Xiao-Lin; Zhang, Qiang

    2016-01-01

    Perovskite oxides with poor conductivity call for three-dimensional (3D) conductive scaffolds to demonstrate their superb reactivities for oxygen evolution reaction (OER). However, perovskite formation usually requires high-temperature annealing at 600° to 900°C in air, under which most of the used conductive frameworks (for example, carbon and metal current collectors) are reductive and cannot survive. We propose a preoxidization coupled electrodeposition strategy in which Co2+ is preoxidized to Co3+ through cobalt Fenton reaction in aqueous solution, whereas the reductive nickel framework is well maintained during the sequential annealing under nonoxidative atmosphere. The in situ–generated Co3+ is inherited into oxidized perovskites deposited on 3D nickel foam, rendering the monolithic perovskite electrocatalysts with extraordinary OER performance with an ultralow overpotential of 350 mV required for 10 mA cm−2, a very small Tafel slope of 59 mV dec−1, and superb stability in 0.10 M KOH. Therefore, we inaugurate a unique strategy for in situ hybridization of oxidative active phase with reductive framework, affording superb reactivity of perovskite electrocatalyst for efficient water oxidation.

  12. Speciation and detection of arsenic in aqueous samples: a review of recent progress in non-atomic spectrometric methods.

    PubMed

    Ma, Jian; Sengupta, Mrinal K; Yuan, Dongxing; Dasgupta, Purnendu K

    2014-06-11

    Inorganic arsenic (As) displays extreme toxicity and is a class A human carcinogen. It is of interest to both analytical chemists and environmental scientists. Facile and sensitive determination of As and knowledge of the speciation of forms of As in aqueous samples are vitally important. Nearly every nation has relevant official regulations on permissible limits of drinking water As content. The size of the literature on As is therefore formidable. The heart of this review consists of two tables: one is a compilation of principal official documents and major review articles, including the toxicology and chemistry of As. This includes comprehensive official compendia on As speciation, sample treatment, recommended procedures for the determination of As in specific sample matrices with specific analytical instrument(s), procedures for multi-element (including As) speciation and analysis, and prior comprehensive reviews on arsenic analysis. The second table focuses on the recent literature (2005-2013, the coverage for 2013 is incomplete) on As measurement in aqueous matrices. Recent As speciation and analysis methods based on spectrometric and electrochemical methods, inductively coupled plasma-mass spectrometry, neutron activation analysis and biosensors are summarized. We have deliberately excluded atomic optical spectrometric techniques (atomic absorption, atomic fluorescence, inductively coupled plasma-optical emission spectrometry) not because they are not important (in fact the majority of arsenic determinations are possibly carried out by one of these techniques) but because these methods are sufficiently mature and little meaningful innovation has been made beyond what is in the officially prescribed compendia (which are included) and recent reviews are available. PMID:24861967

  13. More than just fibers: an aqueous method for the production of innovative recombinant spider silk protein materials.

    PubMed

    Jones, Justin A; Harris, Thomas I; Tucker, Chauncey L; Berg, Kyle R; Christy, Stacia Y; Day, Breton A; Gaztambide, Danielle A; Needham, Nate J C; Ruben, Ashley L; Oliveira, Paula F; Decker, Richard E; Lewis, Randolph V

    2015-04-13

    Spider silk is a striking and robust natural material that has an unrivaled combination of strength and elasticity. There are two major problems in creating materials from recombinant spider silk proteins (rSSps): expressing sufficient quantities of the large, highly repetitive proteins and solvating the naturally self-assembling proteins once produced. To address the second problem, we have developed a method to rapidly dissolve rSSps in water in lieu of traditional organic solvents and accomplish nearly 100% solvation and recovery of the protein. Our method involves generating pressure and temperature in a sealed vial by using short, repetitive bursts from a conventional microwave. The method is scalable and has been successful with all rSSps used to date. From these easily generated aqueous solutions of rSSps, a wide variety of materials have been produced. Production of fibers, films, hydrogels, lyogels, sponges, and adhesives and studies of their mechanical and structural properties are reported. To our knowledge, ours is the only method that is cost-effective and scalable for mass production. This solvation method allows a choice of the physical form of product to take advantage of spider silks' mechanical properties without using costly and problematic organic solvents. PMID:25789668

  14. Comparison of Methods for Predicting the Compositional Dependence of the Density and Refractive Index of Organic-Aqueous Aerosols.

    PubMed

    Cai, Chen; Miles, Rachael E H; Cotterell, Michael I; Marsh, Aleksandra; Rovelli, Grazia; Rickards, Andrew M J; Zhang, Yun-Hong; Reid, Jonathan P

    2016-08-25

    Representing the physicochemical properties of aerosol particles of complex composition is of crucial importance for understanding and predicting aerosol thermodynamic, kinetic, and optical properties and processes and for interpreting and comparing analysis methods. Here, we consider the representations of the density and refractive index of aqueous-organic aerosol with a particular focus on the dependence of these properties on relative humidity and water content, including an examination of the properties of solution aerosol droplets existing at supersaturated solute concentrations. Using bulk phase measurements of density and refractive index for typical organic aerosol components, we provide robust approaches for the estimation of these properties for aerosol at any intermediate composition between pure water and pure solute. Approximately 70 compounds are considered, including mono-, di- and tricarboxylic acids, alcohols, diols, nitriles, sulfoxides, amides, ethers, sugars, amino acids, aminium sulfates, and polyols. We conclude that the molar refraction mixing rule should be used to predict the refractive index of the solution using a density treatment that assumes ideal mixing or, preferably, a polynomial dependence on the square root of the mass fraction of solute, depending on the solubility limit of the organic component. Although the uncertainties in the density and refractive index predictions depend on the range of subsaturated compositional data available for each compound, typical errors for estimating the solution density and refractive index are less than ±0.1% and ±0.05%, respectively. Owing to the direct connection between molar refraction and the molecular polarizability, along with the availability of group contribution models for predicting molecular polarizability for organic species, our rigorous testing of the molar refraction mixing rule provides a route to predicting refractive indices for aqueous solutions containing organic molecules

  15. Comparison of Methods for Predicting the Compositional Dependence of the Density and Refractive Index of Organic-Aqueous Aerosols.

    PubMed

    Cai, Chen; Miles, Rachael E H; Cotterell, Michael I; Marsh, Aleksandra; Rovelli, Grazia; Rickards, Andrew M J; Zhang, Yun-Hong; Reid, Jonathan P

    2016-08-25

    Representing the physicochemical properties of aerosol particles of complex composition is of crucial importance for understanding and predicting aerosol thermodynamic, kinetic, and optical properties and processes and for interpreting and comparing analysis methods. Here, we consider the representations of the density and refractive index of aqueous-organic aerosol with a particular focus on the dependence of these properties on relative humidity and water content, including an examination of the properties of solution aerosol droplets existing at supersaturated solute concentrations. Using bulk phase measurements of density and refractive index for typical organic aerosol components, we provide robust approaches for the estimation of these properties for aerosol at any intermediate composition between pure water and pure solute. Approximately 70 compounds are considered, including mono-, di- and tricarboxylic acids, alcohols, diols, nitriles, sulfoxides, amides, ethers, sugars, amino acids, aminium sulfates, and polyols. We conclude that the molar refraction mixing rule should be used to predict the refractive index of the solution using a density treatment that assumes ideal mixing or, preferably, a polynomial dependence on the square root of the mass fraction of solute, depending on the solubility limit of the organic component. Although the uncertainties in the density and refractive index predictions depend on the range of subsaturated compositional data available for each compound, typical errors for estimating the solution density and refractive index are less than ±0.1% and ±0.05%, respectively. Owing to the direct connection between molar refraction and the molecular polarizability, along with the availability of group contribution models for predicting molecular polarizability for organic species, our rigorous testing of the molar refraction mixing rule provides a route to predicting refractive indices for aqueous solutions containing organic molecules

  16. An aqueous method for the controlled manganese (Mn(2+)) substitution in superparamagnetic iron oxide nanoparticles for contrast enhancement in MRI.

    PubMed

    Ereath Beeran, Ansar; Nazeer, Shaiju S; Fernandez, Francis Boniface; Muvvala, Krishna Surendra; Wunderlich, Wilfried; Anil, Sukumaran; Vellappally, Sajith; Ramachandra Rao, M S; John, Annie; Jayasree, Ramapurath S; Varma, P R Harikrishna

    2015-02-14

    Despite the success in the use of superparamagnetic iron oxide nanoparticles (SPION) for various scientific applications, its potential in biomedical fields has not been exploited to its full potential. In this context, an in situ substitution of Mn(2+) was performed in SPION and a series of ferrite particles, MnxFe1-xFe2O4 with a varying molar ratio of Mn(2+) : Fe(2+) where 'x' varies from 0-0.75. The ferrite particles obtained were further studied in MRI contrast applications and showed appreciable enhancement in their MRI contrast properties. Manganese substituted ferrite nanocrystals (MnIOs) were synthesized using a novel, one-step aqueous co-precipitation method based on the use of a combination of sodium hydroxide and trisodium citrate (TSC). This approach yielded the formation of highly crystalline, superparamagnetic MnIOs with good control over their size and bivalent Mn ion crystal substitution. The presence of a TSC hydrophilic layer on the surface facilitated easy dispersion of the materials in an aqueous media. Primary characterizations such as structural, chemical and magnetic properties demonstrated the successful formation of manganese substituted ferrite. More significantly, the MRI relaxivity of the MnIOs improved fourfold when compared to SPION crystals imparting high potential for use as an MRI contrast agent. Further, the cytocompatibility and blood compatibility evaluations demonstrated excellent cell morphological integrity even at high concentrations of nanoparticles supporting the non-toxic nature of nanoparticles. These results open new horizons for the design of biocompatible water dispersible ferrite nanoparticles with good relaxivity properties via a versatile and easily scalable co-precipitation route. PMID:25586703

  17. THE QUANTIFICATION OF AQUEOUS TRACERS IN LABORATORY AQUIFER MODELS USING A LIGHT TRANSMISSION VISUALIZATION METHOD - 2

    EPA Science Inventory

    The quantification of solute concentrations in laboratory aquifer models has been largely limited to the use of sampling ports, from which samples are collected for external analysis. One of the drawbacks to this method is that the act of sampling may disturb plume dynamics and ...

  18. THE QUANTIFICATION OF AQUEOUS TRACERS IN LABORATORY AQUIFER MODELS USING LIGHT TRANSMISSION VISUALIZATION METHOD

    EPA Science Inventory

    The quantification of solute concentrations in laboratory aquifer models has been largely limited to the use of sampling ports, from which samples are collected for external analysis. One of the drawbacks to this method is that the act of sampling may disturb plume dynamics and ...

  19. THE QUANTIFICATION OF AQUEOUS TRACERS IN LABORATORY AQUIFER MODELS USING A LIGHT TRANSMISSION VISUALIZATION METHOD - 3

    EPA Science Inventory

    The quantification of solute concentrations in laboratory aquifer models has been largely limited to the use of sampling ports, from which samples are collected for external analysis. One of the drawbacks to this method is that the act of sampling may disturb plume dynamics and ...

  20. THE QUANTIFICATION OF AQUEOUS TRACERS IN LABORATORY AQUIFER MODELS USING A LIGHT TRANSMISSION VISUALIZATION METHOD - 1

    EPA Science Inventory

    The quantification of solute concentrations in laboratory aquifer models has been largely limited to the use of sampling ports, from which samples are collected for external analysis. One of the drawbacks to this method is that the act of sampling may disturb plume dynamics and ...

  1. Novel studies of non-aqueous volatiles in lint Cotton moisture tests by complementary thermal methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moisture affects economical and rheological properties of cotton, making its accurate determination important. A significant difference in moisture contents between the current and most cited standard oven drying ASTM method (ASTM D 2495, SOD) and volumetric Karl Fischer Titration (KFT) has been est...

  2. Method and apparatus for controlled size distribution of gel microspheres formed from aqueous dispersions

    DOEpatents

    Ryon, Allen D.; Haas, Paul A.; Vavruska, John S.

    1984-01-01

    The present invention is directed to a method and apparatus for making a population of dense, closely size-controlled microspheres by sol-gel procedures wherein said microspheres are characterized by a significant percentage of said population being within a predetermined, relatively narrow size range. Microsphere populations thus provided are useful in vibratory-packed processes for nuclear fuels to be irradiated in LWR- and FBR-type nuclear reactors.

  3. Superparamagnetic Particle Size Limit of Mn-Zn Ferrite Nanoparticles Synthesised Through Aqueous Method

    SciTech Connect

    Joseyphus, R. Justin; Narayanasamy, A.; Jeyadevan, B.; Shinoda, K.; Tohji, K.

    2006-05-15

    Mn0.67Zn0.33Fe2O4 nanoparticles with size ranging from 20 to 80 nm have been synthesized using the modified oxidation method. The Curie temperatures for all the samples are found to be within 630 {+-} 5 K suggesting that there is no size-dependent cation distribution. Moessbauer studies on the synthesized nanoparticles suggest that the critical particle size limit for superparamagnetism to be about 25 nm at 293 K.

  4. Method for extracting metals from aqueous waste streams for long term storage

    DOEpatents

    Chaiko, D.J.

    1993-01-01

    A liquid-liquid extraction method for removing metals and hydrous metal colloids from waste streams is provided wherein said waste streams are contacted with a solvent system containing a water-in-oil microemulsion wherein the inverted micelles contain the extracted metal. A silicon alkoxide, either alone or in combination with other metal alkoxide compounds is added to the water-in-oil microemulsion, thereby allowing encapsulation of the extracted metal within a silicon oxide network. Lastly, the now-encapsulated metal is precipitated from the water-in-oil microemulsion phase to yield aggregates of metal-silicate particles having average. individual particle sizes of approximately 40 manometers.

  5. Method for extracting metals from aqueous waste streams for long term storage

    DOEpatents

    Chaiko, D.J.

    1995-03-07

    A liquid-liquid extraction method for removing metals and hydrous metal colloids from waste streams is provided wherein said waste streams are contacted with a solvent system containing a water-in-oil microemulsion wherein the inverted micelles contain the extracted metal. A silicon alkoxide, either alone or in combination with other metal alkoxide compounds is added to the water-in-oil microemulsion, thereby allowing encapsulation of the extracted metal within a silicon oxide network. Lastly, the now-encapsulated metal is precipitated from the water-in-oil microemulsion phase to yield aggregates of metal-silicate particles having average individual particle sizes of approximately 40 nanometers. 2 figs.

  6. Method for extracting metals from aqueous waste streams for long term storage

    DOEpatents

    Chaiko, David J.

    1995-01-01

    A liquid--liquid extraction method for removing metals and hydrous metal colloids from waste streams is provided wherein said waste streams are contacted with a solvent system containing a water-in-oil microemulsion wherein the inverted micelles contain the extracted metal. A silicon alkoxide, either alone or in combination with other metal alkoxide compounds is added to the water-in-oil microemulsion, thereby allowing encapsulation of the extracted metal within a silicon oxide network. Lastly, the now-encapsulated metal is precipitated from the water-in-oil microemulsion phase to yield aggregates of metal-silicate particles having average individual particle sizes of approximately 40 nanometers.

  7. Radiospectroscopic method for determining contents of deuterium and tritium in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Gerasimov, R. Y.; Fadeev, G. N.; Gerasimov, Y. V.; Kondratova, E. A.

    2016-09-01

    Radio-wave emission spectra in the microwave region are registered for the first time for ordinary water (H2O), heavy water (D2O), and D2O with a low content of T2O. The obtained spectra are analyzed according to a special program using a hardware-software complex. Measurement results show that the proposed method allows us not only to determine differences between substances in terms of composition and concentration, but to determine the presence of heavy and superheavy hydrogen isotopes in ordinary water as well.

  8. Optimizing Cu(II) removal from aqueous solution by magnetic nanoparticles immobilized on activated carbon using Taguchi method.

    PubMed

    Ebrahimi Zarandi, Mohammad Javad; Sohrabi, Mahmoud Reza; Khosravi, Morteza; Mansouriieh, Nafiseh; Davallo, Mehran; Khosravan, Azita

    2016-01-01

    This study synthesized magnetic nanoparticles (Fe(3)O(4)) immobilized on activated carbon (AC) and used them as an effective adsorbent for Cu(II) removal from aqueous solution. The effect of three parameters, including the concentration of Cu(II), dosage of Fe(3)O(4)/AC magnetic nanocomposite and pH on the removal of Cu(II) using Fe(3)O(4)/AC nanocomposite were studied. In order to examine and describe the optimum condition for each of the mentioned parameters, Taguchi's optimization method was used in a batch system and L9 orthogonal array was used for the experimental design. The removal percentage (R%) of Cu(II) and uptake capacity (q) were transformed into an accurate signal-to-noise ratio (S/N) for a 'larger-the-better' response. Taguchi results, which were analyzed based on choosing the best run by examining the S/N, were statistically tested using analysis of variance; the tests showed that all the parameters' main effects were significant within a 95% confidence level. The best conditions for removal of Cu(II) were determined at pH of 7, nanocomposite dosage of 0.1 gL(-1) and initial Cu(II) concentration of 20 mg L(-1) at constant temperature of 25 °C. Generally, the results showed that the simple Taguchi's method is suitable to optimize the Cu(II) removal experiments. PMID:27386981

  9. One-Step Dipping Method for Covalently Grafting Polymer Films onto a Si Surface from Aqueous Media.

    PubMed

    Zhang, Junhong; Li, Ming; Zhang, Wenqi; Cao, Liqiang

    2016-08-30

    A facile and one-pot dipping method was proposed in this article for the first time to prepare vinylic polymer films on a silicon (Si) surface. This novel process was conducted in acidic aqueous media containing 4-nitrobenzene diazonium (NBD) tetrafluoroborate, hydrofluoric acid (HF), and vinylic monomers at room temperature in the open air and without any apparatus requirement. The formation of the polyvinyl film was confirmed by corroborating evidence from ellipsometry, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM) analysis. The results revealed that both polymers of poorly water soluble methyl methacrylate (MMA) and water-soluble acrylic acid (AA) monomers were covalently grafted onto the Si surface via this simple process. The polyvinyl film was composed of polynitrophenyl (PNP) and polyvinyl, where PNP was doped into polyvinyl chains throughout the entire film. From a mechanistic point of view, the simple dipping method took advantage of the ability of the NBD cation to be spontaneously reduced at the Si surface at open circuit potential, providing aryl radicals. These radicals can be covalently bonded to the Si surface to form the PNP primer layer. Although the PNP sublayer was thinner and difficult to detect, it was necessary to graft polyvinyl chains. Furthermore, the aryl radicals were used to initiate the polymerization of vinylic monomers. The radical-terminated polyvinyl chains formed in the solution were then added to the aromatic rings of the primer layer to form the expected polyvinyl film. PMID:27441573

  10. Preparation of Metallic Aluminum Compound Particles by Submerged Arc Discharge Method in Aqueous Media

    NASA Astrophysics Data System (ADS)

    Liao, Chih-Yu; Tseng, Kuo-Hsiung; Lin, Hong-Shiou

    2013-02-01

    Fine metal particles are produced by chemical methods, which add surfactants to control particle size and concentration. This study used the submerged arc discharge method (SADM) to prepare metal fluid containing nanoparticles and submicron particles in pure dielectric fluid (deionized water or alcohol). The process is fast and simple, and it does not require the addition of chemical agents. The SADM uses electrical discharge machining (EDM) equipment, and the key parameters of the production process include discharge voltage, current, and pulse discharge on-off duration. This study added a capacitive component between the electrodes and the electrode Z-axis regulation in the control parameters to render the aluminum fluid process smooth, which is the main difference of this article from the literature. The experimental results showed that SADM can produce aluminum particles from nanometer to submicron grade, and it can obtain different compounds from different dielectric fluids. The dielectric fluids used in this study were deionized water and ethanol, and aluminum hydroxide Al(OH)3 particles with suspending power and precipitated aluminum particles were obtained, respectively. The preparations of metal colloid and particles by the SADM process have the characteristics of low cost, high efficiency, high speed, and mass production. Thus, the process has high research value and developmental opportunities.

  11. Degradation and removal methods of antibiotics from aqueous matrices--a review.

    PubMed

    Homem, Vera; Santos, Lúcia

    2011-10-01

    Over the past few years, antibiotics have been considered emerging pollutants due to their continuous input and persistence in the aquatic ecosystem even at low concentrations. They have been detected worldwide in environmental matrices, indicating their ineffective removal from water and wastewater using conventional treatment methods. To prevent this contamination, several processes to degrade/remove antibiotics have been studied. This review addresses the current state of knowledge concerning the input sources, occurrence and mainly the degradation and removal processes applied to a specific class of micropollutants, the antibiotics. In this paper, different remediation techniques were evaluated and compared, such as conventional techniques (biological processes, filtration, coagulation, flocculation and sedimentation), advanced oxidation processes (AOPs), adsorption, membrane processes and combined methods. In this study, it was found that ozonation, Fenton/photo-Fenton and semiconductor photocatalysis were the most tested methodologies. Combined processes seem to be the best solution for the treatment of effluents containing antibiotics, especially those using renewable energy and by-products materials.

  12. Linear and nonlinear methods in modeling the aqueous solubility of organic compounds.

    PubMed

    Catana, Cornel; Gao, Hua; Orrenius, Christian; Stouten, Pieter F W

    2005-01-01

    Solubility data for 930 diverse compounds have been analyzed using linear Partial Least Square (PLS) and nonlinear PLS methods, Continuum Regression (CR), and Neural Networks (NN). 1D and 2D descriptors from MOE package in combination with E-state or ISIS keys have been used. The best model was obtained using linear PLS for a combination between 22 MOE descriptors and 65 ISIS keys. It has a correlation coefficient (r2) of 0.935 and a root-mean-square error (RMSE) of 0.468 log molar solubility (log S(w)). The model validated on a test set of 177 compounds not included in the training set has r2 0.911 and RMSE 0.475 log S(w). The descriptors were ranked according to their importance, and at the top of the list have been found the 22 MOE descriptors. The CR model produced results as good as PLS, and because of the way in which cross-validation has been done it is expected to be a valuable tool in prediction besides PLS model. The statistics obtained using nonlinear methods did not surpass those got with linear ones. The good statistic obtained for linear PLS and CR recommends these models to be used in prediction when it is difficult or impossible to make experimental measurements, for virtual screening, combinatorial library design, and efficient leads optimization.

  13. A simple synthesis method to produce metal oxide loaded carbon paper using bacterial cellulose gel and characterization of its electrochemical behavior in an aqueous electrolyte

    NASA Astrophysics Data System (ADS)

    Miyajima, Naoya; Jinguji, Ken; Matsumura, Taiyu; Matsubara, Toshihiro; Sakane, Hideto; Akatsu, Takashi; Tanaike, Osamu

    2016-04-01

    A simple synthetic chemical process to produce metal oxide loaded carbon papers was developed using bacterial cellulose gel, which consisted of nanometer-sized fibrous cellulose and water. Metal ions were successfully impregnated into the gel via aqueous solution media before drying and carbonization methods resulting in metal oxide contents that were easy to control through variations in the concentration of aqueous solutions. The papers loaded by molybdenum oxides were characterized as pseudocapacitor electrodes preliminary, and the large redox capacitance of the oxides was followed by a conductive fibrous carbon substrate, suggesting that a binder and carbon black additive-free electrode consisting of metal oxides and carbon paper was formed.

  14. An enzymatic method for determination of azide and cyanide in aqueous phase.

    PubMed

    Wan, Nan-Wei; Liu, Zhi-Qiang; Xue, Feng; Zheng, Yu-Guo

    2015-11-20

    A halohydrin dehalogenase (HHDH-PL) from Parvibaculum lavamentivorans DS-1 was characterized and applied to determine azide and cyanide in the water. In this methodology, HHDH-PL catalysed azide and cyanide to react with butylene oxide and form corresponding β-substituted alcohols 1-azidobutan-2-ol (ABO) and 3-hydroxypentanenitrile (HPN) that could be quantitatively detected by gas chromatograph. The detection calibration curves for azide (R(2)=0.997) and cyanide (R(2)=0.995) were linear and the lower limits of detection for azide and cyanide were 0.1 and 0.3mM, respectively. Several other nucleophiles were identified having no effect on the analysis of azide and cyanide, excepting nitrite which influenced the detection of cyanide. This was the first report of a biological method to determine the inorganic azide and cyanide by converting them to the measurable organics.

  15. OZONATION BY-PRODUCTS 2. IMPROVEMENT OF AN AQUEOUS- PHASE DERIVITIZATION METHOD FOR THE DETECTION OF FORMALDEHYDE AND OTHER CARBONYL COMPOUNDS FORMED BY THE OZONATION OF DRINKING WATER

    EPA Science Inventory

    A method for the determination of low molecular weight aldehydes in water using aqueous-phase derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride has been improved by the use of high-resolution capillary GC. Detection limits with GC/ECD and GC/MS with ...

  16. A sensitive non-aqueous capillary electrophoresis-mass spectrometric method for multiresidue analyses of beta-agonists in pork.

    PubMed

    Anurukvorakun, Oraphan; Buchberger, Wolfgang; Himmelsbach, Markus; Klampel, Christian W; Suntornsuk, Leena

    2010-06-01

    Non-aqueous capillary electrophoresis-mass spectrometry (NACE-MS) was developed for trace analyses of beta-agonists (i.e. clenbuterol, salbutamol and terbutaline) in pork. The NACE was in 18 mM ammonium acetate in methanol-acetonitrile-glacial acetic acid (66 : 33 : 1, v/v/v) using a voltage of 28 kV. The hyphenation of CE with a time-of-flight MS was performed by electrospray ionization interface employing 5 mM ammonium acetate in methanol-water (80 : 20, v/v) as the sheath liquid at a flow rate of 2 microL/min. Method sensitivity was enhanced by a co-injection technique (combination of hydrodynamic and electrokinetic injection) using a pressure of 50 mbar and a voltage of 10 kV for 12 s. The method was validated in comparison with HPLC-MS-MS. The NACE-MS procedure provided excellent detection limits of 0.3 ppb for all analytes. Method linearity was good (r(2) > 0.999, in a range of 0.8-1000 ppb for all analytes). Precision showed %RSDs of <17.7%. Sample pre-treatment was carried out by solid-phase extraction using mixed mode reversed phase/cation exchange cartridges yielding recoveries between 69 and 80%. The NACE-MS could be successfully used for the analysis of beta-agonists in pork samples and results showed no statistical differences from the values reported by the Ministry of Public Health, Thailand using HPLC-MS-MS method.

  17. Isolation of calcium-phosphate crystals of bone by non-aqueous methods at low temperature.

    PubMed

    Kim, H M; Rey, C; Glimcher, M J

    1995-10-01

    We have developed low temperature nonaqueous solution methods as well as low power plasma ashing for the degradation of the organic matrix of bone power which have permitted us to obtain bone crystals essentially free of organic matrix constituents without any significant change in their composition, overall structure, or internal short-range order. We have also been able to disperse the crystals, which has made it possible to examine the isolated crystals by X-ray diffraction and resolution-enhanced Fourier transform infrared (FTIR) spectroscopy and isolated single crystals by high resolution transmission electron microscopy (TEM) and electron diffraction. TEM of isolated single crystals of fish, chicken, mouse and bovine bone have clearly demonstrated that the crystals are very thin plates. No rod or needle-like crystals were observed in any of the bone samples in the four species studied including the earliest crystals deposited. Although there were variations in the size distribution of the crystals in the different species studied, in general the average crystal dimensions were very similar.

  18. Anti-Bacterial effect of Aqueous Garlic Extract (AGE) determined by Disc Diffusion Method against Escherichia coli.

    PubMed

    Saha, S; Saha, S K; Hossain, M A; Paul, S K; Gomes, R R; Imtiaz, M; Islam, M M; Nahar, H; Begum, S A; Mirza, T T

    2016-01-01

    The study was performed to determine the antibacterial effect of aqueous extract of garlic (Allium sativum) against standard strain of Escherichia coli ATCC 25922. An interventional study was conducted in Department of Pharmacology and Therapeutics in collaboration with Department of Microbiology, Mymensingh Medical College, Mymensingh. Antibacterial effect of AGE was determined by disc diffusion method. Sensitivity of AGE determined in disc diffusion and the zone of inhibition (ZOI) was 4 mm, 10 mm and 20 mm at 25 μg/10 μl, 50 μg/10 μl and 100 μg/10 μl concentrations respectively. From the findings it is clearly determined the extract has definite antibacterial effect upon Escherichia coli. Further studies are required to detect and isolate the active ingredients present in the Garlic extract as well as detail steps of mechanism responsible for antibacterial effect. Then their effects against the studied organism should be studied in vivo separately and its toxicity profile should also be taken into account.

  19. Anti-Bacterial effect of Aqueous Garlic Extract (AGE) determined by Disc Diffusion Method against Escherichia coli.

    PubMed

    Saha, S; Saha, S K; Hossain, M A; Paul, S K; Gomes, R R; Imtiaz, M; Islam, M M; Nahar, H; Begum, S A; Mirza, T T

    2016-01-01

    The study was performed to determine the antibacterial effect of aqueous extract of garlic (Allium sativum) against standard strain of Escherichia coli ATCC 25922. An interventional study was conducted in Department of Pharmacology and Therapeutics in collaboration with Department of Microbiology, Mymensingh Medical College, Mymensingh. Antibacterial effect of AGE was determined by disc diffusion method. Sensitivity of AGE determined in disc diffusion and the zone of inhibition (ZOI) was 4 mm, 10 mm and 20 mm at 25 μg/10 μl, 50 μg/10 μl and 100 μg/10 μl concentrations respectively. From the findings it is clearly determined the extract has definite antibacterial effect upon Escherichia coli. Further studies are required to detect and isolate the active ingredients present in the Garlic extract as well as detail steps of mechanism responsible for antibacterial effect. Then their effects against the studied organism should be studied in vivo separately and its toxicity profile should also be taken into account. PMID:26931244

  20. Competitive removal of hazardous dyes from aqueous solution by MIL-68(Al): Derivative spectrophotometric method and response surface methodology approach

    NASA Astrophysics Data System (ADS)

    Tehrani, Mahnaz Saghanejhad; Zare-Dorabei, Rouholah

    2016-05-01

    MIL-68(Al) as a metal-organic framework (MOF) was synthesized and characterized by different techniques such as SEM, BET, FTIR, and XRD analysis. This material was then applied for simulations removal of malachite green (MG) and methylene blue (MB) dyes from aqueous solutions using second order derivative spectrophotometric method (SODS) which was applied to resolve the overlap between the spectra of these dyes. The dependency of dyes removal efficiency in binary solutions was examined and optimized toward various parameters including initial dye concentration, pH of the solution, adsorbent dosage and ultrasonic contact time using central composite design (CCD) under response surface methodology (RSM) approach. The optimized experimental conditions were set as pH 7.78, contact time 5 min, initial MB concentration 22 mg L- 1, initial MG concentration 12 mg L- 1 and adsorbent dosage 0.0055 g. The equilibrium data was fitted to isotherm models such as Langmuir, Freundlich and Tempkin and the results revealed the suitability of the Langmuir model. The maximum adsorption capacity of 666.67 and 153.85 mg g- 1 was obtained for MB and MG removal respectively. Kinetics data fitting to pseudo-first order, pseudo-second order and Elovich models confirmed the applicability of pseudo-second order kinetic model for description of the mechanism and adsorption rate. Dye-loaded MIL-68(Al) can be easily regenerated using methanol and applied for three frequent sorption/desorption cycles with high performance. The impact of ionic strength on removal percentage of both dyes in binary mixture was studied by using NaCl and KCl soluble salts at different concentrations. According to our findings, only small dosage of the proposed MOF is considerably capable to remove large amounts of dyes at room temperature and in very short time that is a big advantage of MIL-68(Al) as a promising adsorbent for adsorptive removal processes.

  1. Transition from micelle to vesicle in aqueous mixtures of anionic/zwitterionic surfactants studied by fluorescence, conductivity, and turbidity methods.

    PubMed

    Zhai, Limin; Zhang, Jiyu; Shi, Qingxiu; Chen, Wenjun; Zhao, Mei

    2005-04-15

    Vesicles form spontaneously in a aqueous mixture of sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol OT) and lauryl sulfonate betaine (LSB). Different from catanionic vesicles, the formation or disaggregation of such zwitterionic/anionic vesicles may be easily controlled by adjusting the relative amount of LSB and salinity. The participation of LSB reduces the polydispersity of the vesicles and even results in the formation of monodispersed vesicles at a certain salinity. But as LSB exceeds a certain proportion, vesicles cannot form at any concentration and salinity, making convenient the study of the structural transitions. We applied pyrene as a fluorescence probe and monitored the transition among the monomer, micelle, and vesicle through the variation of I(1)/I(3), accompanied by conductivity and turbidity measurements. In LSB solution and LSB-rich mixture, an abrupt change of the ratio of I(1)/I(3) was found in the transition from monomer to micelle with increasing concentration, as well as in the transition from micelle to vesicle with increasing salinity, which shows that a difference of the polarity of the microenvironment between the micelle and the vesicle bilayer resulted from the composition change. But in AOT solution and AOT-rich mixture, only a gradual change in the transition is observed due to the existence of intermediate structures, which have different microenvironments from micelles and vesicles. So the formation of vesicle experiences a process of monomer to premicelle to micelle to bilayer segment with increasing concentration by combining the conductivity method. The ratio of I(1)/I(3) is independent of the vesicle size once formed.

  2. Competitive removal of hazardous dyes from aqueous solution by MIL-68(Al): Derivative spectrophotometric method and response surface methodology approach.

    PubMed

    Tehrani, Mahnaz Saghanejhad; Zare-Dorabei, Rouholah

    2016-05-01

    MIL-68(Al) as a metal-organic framework (MOF) was synthesized and characterized by different techniques such as SEM, BET, FTIR, and XRD analysis. This material was then applied for simulations removal of malachite green (MG) and methylene blue (MB) dyes from aqueous solutions using second order derivative spectrophotometric method (SODS) which was applied to resolve the overlap between the spectra of these dyes. The dependency of dyes removal efficiency in binary solutions was examined and optimized toward various parameters including initial dye concentration, pH of the solution, adsorbent dosage and ultrasonic contact time using central composite design (CCD) under response surface methodology (RSM) approach. The optimized experimental conditions were set as pH7.78, contact time 5min, initial MB concentration 22mgL(-1), initial MG concentration 12mgL(-1) and adsorbent dosage 0.0055g. The equilibrium data was fitted to isotherm models such as Langmuir, Freundlich and Tempkin and the results revealed the suitability of the Langmuir model. The maximum adsorption capacity of 666.67 and 153.85mgg(-1) was obtained for MB and MG removal respectively. Kinetics data fitting to pseudo-first order, pseudo-second order and Elovich models confirmed the applicability of pseudo-second order kinetic model for description of the mechanism and adsorption rate. Dye-loaded MIL-68(Al) can be easily regenerated using methanol and applied for three frequent sorption/desorption cycles with high performance. The impact of ionic strength on removal percentage of both dyes in binary mixture was studied by using NaCl and KCl soluble salts at different concentrations. According to our findings, only small dosage of the proposed MOF is considerably capable to remove large amounts of dyes at room temperature and in very short time that is a big advantage of MIL-68(Al) as a promising adsorbent for adsorptive removal processes. PMID:26890205

  3. Microchip Non-Aqueous Capillary Electrophoresis (MicronNACE) Method to Analyze Long-Chain Primary Amines

    NASA Technical Reports Server (NTRS)

    Willis, Peter A.; Mora, Maria; Cable, Morgan L.; Stockton, Amanda M.

    2012-01-01

    A protocol was developed as a first step in analyzing the complex organic aerosols present on Saturn's moon Titan, as well as the analogues of these aerosols (tholins) made on Earth. Labeling of primary amines using Pacific Blue succinimidyl ester is effected in ethanol with 25 mM triethylamine to maintain basic conditions. This reaction is allowed to equilibrate for at least one hour. Separation of the labeled primary amines is performed in ethanol with 1.05 M acetic acid, and 50 mM ammonium acetate in a commercial two-layer glass device with a standard crossmicrochannel measuring 50 microns wide by 20 microns deep. Injection potentials are optimized at 2 kV from the sample (negative) to the waste well (positive), with slight bias applied to the other two wells ( 0.4 and 0.8 V) to pinch the injection plug for the 30-s injection. Separation is performed at a potential of 5 kV along the channel, which has an effective separation distance of 7 cm. The use of ethanol in this method means that long-chain primary amines can be dissolved. Due to the low pH of the separation buffer, electro-osmotic flow (EOF) is minimized to allow for separation of both short-chain and longchain amines. As the freezing point of ethanol is much lower than water, this protocol can perform separations at temperatures lower than 0 C, which would not be possible in aqueous phase. This is of particular importance when considering in situ sampling of Titan aerosols, where unnecessary heating of the sample (even to room temperature) would lead to decomposition or unpredictable side reactions, which would make it difficult to characterize the sample appropriately.

  4. Interference of some aqueous two-phase system phase-forming components in protein determination by the Bradford method.

    PubMed

    Silvério, Sara C; Moreira, Sérgio; Milagres, Adriane M F; Macedo, Eugénia A; Teixeira, José A; Mussatto, Solange I

    2012-02-15

    The interference of some specific aqueous two-phase system (ATPS) phase-forming components in bovine serum albumin (BSA) determination by the Bradford method was investigated. For this purpose, calibration curves were obtained for BSA in the presence of different concentrations of salts and polymers. A total of 19 salts [Na₂SO₄, (NH₄)₂SO₄, MgSO₄, LiSO₄, Na₂HPO₄, sodium phosphate buffer (pH 7.0), NaH₂PO₄, K₂HPO₄, potassium phosphate buffer (pH 7.0), KH₂PO₄, C₆H₈O₇, Na₃C₆H₅O₇, KCHO₂, NaCHO₂, NaCO₃, NaHCO₃, C₂H₄O₂, sodium acetate buffer (pH 4.5), and NaC₂H₃O₂] and 7 polymers [PEG 4000, PEG 8000, PEG 20000, UCON 3900, Ficoll 70000, PES 100000, and PVP 40000] were tested, and each calibration curve was compared with the one obtained for BSA in water. Some concentrations of salts and polymers had considerable effect in the BSA calibration curve. Carbonate salts were responsible for the highest salt interference, whereas citric and acetic acids did not produce interference even in the maximum concentration level tested (5 wt%). Among the polymers, UCON gave the highest interference, whereas Ficoll did not produce interference when used in concentrations up to 10 wt%. It was concluded that a convenient dilution of the samples prior to the protein quantification is needed to ensure no significant interference from ATPS phase-forming constituents.

  5. Device of dispensing micro doses of aqueous solutions of substances onto a carrier and device for carrying out said method

    DOEpatents

    Ershow, Gennady Moiseevich; Kirillov, Evgenii Vladislavovich; Mirzabekov, Andrei Darievich

    1998-01-01

    A device for dispensing microdoses of aqueous solutions are provided, whereby the substance is transferred by the free surface end of a rodlike transferring element; the temperature of the transferring element is maintained at essentially the dew point of the ambient air during the transfer. The device may comprise a plate-like base to which are affixed a plurality of rods; the unfixed butt ends of the rods are coplanar. The device further comprises a means for maintaining the temperature of the unfixed butt ends of the rods essentially equal to the dew point of the ambient air during transfer of the aqueous substance.

  6. Effects of Metal Ions on Viscosity of Aqueous Sodium Carboxylmethylcellulose Solution and Development of Dropping Ball Method on Viscosity

    ERIC Educational Resources Information Center

    Set, Seng; Ford, David; Kita, Masakazu

    2015-01-01

    This research revealed that metal ions with different charges could significantly affect the viscosity of aqueous sodium carboxylmethylcellulose (CMC) solution. On the basis of an Ostwald viscometer, an improvised apparatus using a dropping ball for examining the viscosity of liquids/solutions has been developed. The results indicate that the…

  7. Highly Selective Olefin Epoxidation with Aqueous H₂O₂ Over Surfacemodified TaSBA15 Prepared via the TMP Method

    SciTech Connect

    Ruddy, Daniel A.; Tilley, T. D.

    2007-07-17

    Trialkylsiloxy-modified Ta(V) centers on mesoporous silica exhibit excellent selectivity for epoxide formation (>98% after 2 h) in the oxidation of cyclohexene using aqueous H₂O₂ as the oxidant; the modified catalysts exhibit an increased lifetime, retaining high selectivity after 6 h of reaction (>95% epoxide).

  8. Co-solvent evaporation method for enhancement of solubility and dissolution rate of poorly aqueous soluble drug simvastatin: in vitro-in vivo evaluation.

    PubMed

    Pandya, Priyanka; Gattani, Surendra; Jain, Pankaj; Khirwal, Lokesh; Surana, Sanjay

    2008-01-01

    A number of synthesized chemical molecules suffer from low aqueous solubility problems. Enhancement of aqueous solubility, dissolution rate, and bioavailability of drug is a very challenging task in drug development. In the present study, solubility and dissolution of poorly aqueous soluble drug simvastatin (SIM) was enhanced using hydrophilic, low viscosity grade polymer hydroxypropyl methylcellulose (HPMC K(3)LV). The co-solvent evaporation method was developed for efficient encapsulation of hydrophobic drug in polymer micelles of HPMC K(3)LV. Spray drying and rotaevaporation method were applied for solvent evaporation. Co-solvent-evaporated mixture in solid state was determined by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD), scanning electron microscopy, and Fourier-transform infrared spectroscopy. In vitro-in vivo studies were performed on co-solvent-evaporated mixture and compared with SIM. In vivo study was conducted on healthy albino rats (Wister strain), and formulations were administered by oral route. Results of the study show the conversion of crystalline form of SIM into amorphous form. The dissolution rate was remarkably increased in co-solvent-evaporated mixtures compared to SIM. co-solvent-evaporated mixtures showed better reduction in total cholesterol and triglyceride levels than the SIM. The low-viscosity grade HPMC acts as a surfactant, which enhances the wetting of drug and thus improves the solubility of drug. The co-solvent evaporation method provides good encapsulation efficiency and produces amorphous form of SIM, which gave better solubility and dissolution than the crystalline SIM.

  9. A LC-MS method allowing the analysis of HMX and RDX present at the picogram level in natural aqueous samples without a concentration step.

    PubMed

    Vigneau, Olivier; Machuron-Mandard, Xavier

    2009-03-15

    The introduction of chloroform into the nebulising gas of a LC/MS electrospray interface (ESI), in a perfectly controlled way, leads to the formation of intense adducts ([M+Cl](-)) when a mobile phase containing HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane or octogen) and RDX (1,3,5-trintro-1,3,5-triazacyclohexane or hexogen) is eluted. This LC/MS method allows the direct analysis of aqueous samples containing HMX and RDX at the pictogram level without a concentration step. The method is used to determine HMX and RDX concentrations in ground water samples from a military site.

  10. A New Modal Analysis Method to put Constraints on the Aqueous Alteration of CR Chondrites and Estimate the Unaltered CR Composition

    NASA Technical Reports Server (NTRS)

    Perronnet, M.; Zolensky, M. E.; Gounelle, M.; Schwandt, C. S.

    2007-01-01

    carbonaceous chondrites are of the major interest since they contain one of the most primitive organic matters. However, aqueous alteration has more or less overprinted their original features in a way that needed to be assessed. That was done in the present study by comparing the mineralogy of the most altered CR1 chondrite, GRO 95577, to a less altered CR2, Renazzo. Their modal analyses were achieved thanks to a new method, based on X-ray elemental maps acquired on electron microprobe, and on IDL image treatment. It allowed the collection of new data on the composition of Renazzo and confirmed the classification of GRO 95577 as a CR1. New alteration products for CRs, vermiculite and clinochlore, were observed. The homogeneity of the Fe-poor clays in the CR1 and the distinctive matrix composition in the two chondrites suggest a wide-range of aqueous alteration on CRs. The preservation of the outlines of the chondrules in GRO 95577 and the elemental transfers of Al, Fe and Ca throughout the chondrule and of Fe and S from the matrix to the chondrule favor the idea of an asteroidal location of the aqueous alteration. From their mineralogical descriptions and modal abundances, the element repartitions in Renazzo and GRO 95577 were computed. It indicates a possible relationship between these two chondrites via an isochemical alteration process. Knowing the chemical reactions that occurred during the alteration, it was thus possible to decipher the mineralogical modal abundances in the unaltered CR body.

  11. A New Modal Analysis Method to put Constraints on the Aqueous Alteration of CR Chondrites and Estimate the Unaltered CR Composition

    NASA Technical Reports Server (NTRS)

    Perronnet, M.; Zolensky, M. E.; Gounelle, M.; Schwandt, C. S.

    2007-01-01

    CR carbonaceous chondrites are of the major interest since they contain one of the most primitive organic matters. However, aqueous alteration has more or less overprinted their original features in a way that needed to be assessed. That was done in the present study by comparing the mineralogy of the most altered CR1 chondrite, GRO 95577, to a less altered CR2, Renazzo. Their modal analyses were achieved thanks to a new method, based on X-ray elemental maps acquired on electron microprobe, and on IDL image treatment. It allowed the collection of new data on the composition of Renazzo and confirmed the classification of GRO 95577 as a CR1. New alteration products for CRs, vermiculite and clinochlore, were observed. The homogeneity of the Fe-poor clays in the CR1 and the distinctive matrix composition in the two chondrites suggest a wide-range of aqueous alteration on CRs. The preservation of the outlines of the chondrules in GRO 95577 and the elemental transfers of Al, Fe and Ca throughout the chondrule and of Fe and S from the matrix to the chondrule favor the idea of an asteroidal location of the aqueous alteration. From their mineralogical descriptions and modal abundances, the element repartitions in Renazzo and GRO 95577 were computed. It indicates a possible relationship between these two chondrites via an isochemical alteration process. Knowing the chemical reactions that occurred during the alteration, it was thus possible to decipher the mineralogical modal abundances in the unaltered CR body.

  12. Adsorption of cefixime from aqueous solutions using modified hardened paste of Portland cement by perlite; optimization by Taguchi method.

    PubMed

    Rasoulifard, Mohammad Hossein; Khanmohammadi, Soghra; Heidari, Azam

    2016-01-01

    In the present study, we have used a simple and cost-effective removal technique by a commercially available Fe-Al-SiO2 containing complex material (hardened paste of Portland cement (HPPC)). The adsorbing performance of HPPC and modified HPPC with perlite for removal of cefixime from aqueous solutions was investigated comparatively by using batch adsorption studies. HPPC has been selected because of the main advantages such as high efficiency, simple separation of sludge, low-cost and abundant availability. A Taguchi orthogonal array experimental design with an OA16 (4(5)) matrix was employed to optimize the affecting factors of adsorbate concentration, adsorbent dosage, type of adsorbent, contact time and pH. On the basis of equilibrium adsorption data, Langmuir, Freundlich and Temkin adsorption isotherm models were also confirmed. The results showed that HPPC and modified HPPC were both efficient adsorbents for cefixime removal. PMID:27642826

  13. Synthesis and Characterization of Eu3+-Doped CdS Quantum Dots by a Single-Step Aqueous Method.

    PubMed

    Zhou, Chunyan; Song, Jiahui; Zhang, Xinguo; Sun, Lu; Zhou, Liya; Huang, Ni; Gan, Yufei; Chen, Mengyang; Zhang, Wei

    2016-04-01

    Eu3+-doped CdS quantum dots (QDs) are successfully synthesized through a straightforward single-pot process in aqueous solution using thioglycolic acid as the capping ligand. The structure, shape, and spectral properties of the QDs are investigated. The obtained CdS:Eu3+ QDs exhibit cubic structures with good crystallinity and approximately sphere-like shapes about 4 nm in diameter. The CdS QDs manifest a broadband emission peak at 600 nm and enhanced Photoluminescence (PL) emission intensity after doping with Eu3+ ions. Given the strong PL intensity and good chromaticity of the sulfide-based QDs, they have potential use in doping rare-earth ions. PMID:27451722

  14. Method To Determine Protein Concentration in the Protein-Nanoparticle Conjugates Aqueous Solution Using Circular Dichroism Spectroscopy.

    PubMed

    Li, Shanghao; Peng, Zhili; Leblanc, Roger M

    2015-07-01

    Considerable efforts have been made to synthesize and characterize protein-nanoparticle conjugates (protein-NPs) for their promising applications in bionanotechnology. However, protein concentration determination in the protein-NPs has so far not been reported. In this Letter, we present a simple and nondestructive approach to quantify the protein concentration in the protein-NPs aqueous solution using circular dichroism (CD) spectroscopy. Carbon dots (∼4 nm), gold nanoparticles (∼10 nm), and polyethylene glycol (PEG, molecular weight ∼3000) were either physically mixed or covalently conjugated (not in the case of gold nanoparticles) with proteins (human transferrin, human serum albumin, and ovalbumin). We were able to quantify the protein concentration in the protein-nanoparticle conjugates using a calibration curve from the CD spectra. PMID:26070096

  15. Adsorption of cefixime from aqueous solutions using modified hardened paste of Portland cement by perlite; optimization by Taguchi method.

    PubMed

    Rasoulifard, Mohammad Hossein; Khanmohammadi, Soghra; Heidari, Azam

    2016-01-01

    In the present study, we have used a simple and cost-effective removal technique by a commercially available Fe-Al-SiO2 containing complex material (hardened paste of Portland cement (HPPC)). The adsorbing performance of HPPC and modified HPPC with perlite for removal of cefixime from aqueous solutions was investigated comparatively by using batch adsorption studies. HPPC has been selected because of the main advantages such as high efficiency, simple separation of sludge, low-cost and abundant availability. A Taguchi orthogonal array experimental design with an OA16 (4(5)) matrix was employed to optimize the affecting factors of adsorbate concentration, adsorbent dosage, type of adsorbent, contact time and pH. On the basis of equilibrium adsorption data, Langmuir, Freundlich and Temkin adsorption isotherm models were also confirmed. The results showed that HPPC and modified HPPC were both efficient adsorbents for cefixime removal.

  16. Determination of Aroma Compound Partition Coefficients in Aqueous, Polysaccharide, and Dairy Matrices Using the Phase Ratio Variation Method: A Review and Modeling Approach.

    PubMed

    Heilig, Andrej; Sonne, Alina; Schieberle, Peter; Hinrichs, Jörg

    2016-06-01

    The partition of aroma compounds between a matrix and a gas phase describes an individual compound's specific affinity toward the matrix constituents affecting orthonasal sensory perception. The static headspace phase ratio variation (PRV) method has been increasingly applied by various authors to determine the equilibrium partition coefficient K in aqueous, polysaccharide, and dairy matrices. However, reported partition coefficients are difficult to relate and compare due to different experimental conditions, e.g., aroma compound selection, matrix composition, equilibration temperature. Due to its specific advantages, the PRV method is supposed to find more frequent application in the future, this Review aims to summarize, evaluate, compare, and relate the currently available data on PRV-determined partition coefficients. This process was designed to specify the potentials and the limitations as well as the consistency of the PRV method, and to identify open fields of research in aroma compound partitioning in food-related, especially dairy matrices.

  17. Determination of Aroma Compound Partition Coefficients in Aqueous, Polysaccharide, and Dairy Matrices Using the Phase Ratio Variation Method: A Review and Modeling Approach.

    PubMed

    Heilig, Andrej; Sonne, Alina; Schieberle, Peter; Hinrichs, Jörg

    2016-06-01

    The partition of aroma compounds between a matrix and a gas phase describes an individual compound's specific affinity toward the matrix constituents affecting orthonasal sensory perception. The static headspace phase ratio variation (PRV) method has been increasingly applied by various authors to determine the equilibrium partition coefficient K in aqueous, polysaccharide, and dairy matrices. However, reported partition coefficients are difficult to relate and compare due to different experimental conditions, e.g., aroma compound selection, matrix composition, equilibration temperature. Due to its specific advantages, the PRV method is supposed to find more frequent application in the future, this Review aims to summarize, evaluate, compare, and relate the currently available data on PRV-determined partition coefficients. This process was designed to specify the potentials and the limitations as well as the consistency of the PRV method, and to identify open fields of research in aroma compound partitioning in food-related, especially dairy matrices. PMID:27182770

  18. High-Performance Olivine NaFePO4 Microsphere Cathode Synthesized by Aqueous Electrochemical Displacement Method for Sodium Ion Batteries.

    PubMed

    Fang, Yongjin; Liu, Qi; Xiao, Lifen; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2015-08-19

    Olivine NaFePO4/C microsphere cathode is prepared by a facile aqueous electrochemical displacement method from LiFePO4/C precursor. The NaFePO4/C cathode shows a high discharge capacity of 111 mAh g(-1), excellent cycling stability with 90% capacity retention over 240 cycles at 0.1 C, and high rate capacity (46 mAh g(-1) at 2 C). The excellent electrochemical performance demonstrates that the aqueous electrochemical displacement method is an effective and promising way to prepare NaFePO4/C material for Na-based energy storage applications. Moreover, the Na2/3FePO4 intermediate is observed for the first time during the Na intercalation process through conventional electrochemical techniques, corroborating an identical two-step phase transition reaction both upon Na intercalation and deintercalation processes. The clarification of the electrochemical reaction mechanism of olivine NaFePO4 could inspire more attention on the investigation of this material for Na ion batteries.

  19. Evaluation of phosphorus adsorption capacity of sesame straw biochar on aqueous solution: influence of activation methods and pyrolysis temperatures.

    PubMed

    Park, J H; Ok, Y S; Kim, S H; Cho, J S; Heo, J S; Delaune, R D; Seo, D C

    2015-12-01

    The phosphorus (P) adsorption characteristic of sesame straw biochar prepared with different activation agents and pyrolysis temperatures was evaluated. Between 0.109 and 0.300 mg L(-1) in the form of inorganic phosphate was released from raw sesame straw biochar in the first 1 h. The release of phosphate was significantly enhanced from 62.6 to 168.2 mg g(-1) as the pyrolysis temperature increased. Therefore, sesame straw biochar cannot be used as an adsorbent for P removal without change in the physicochemical characteristics. To increase the P adsorption of biochar in aqueous solution, various activation agents and pyrolysis temperatures were applied. The amount of P adsorbed from aqueous solution by biochar activated using different activation agents appeared in the order ZnCl2 (9.675 mg g(-1)) > MgO (8.669 mg g(-1)) ⋙ 0.1N-HCl > 0.1N-H2SO4 > K2SO4 ≥ KOH ≥ 0.1N-H3PO4, showing ZnCl2 to be the optimum activation agent. Higher P was adsorbed by the biochar activated using ZnCl2 under different pyrolysis temperatures in the order 600 °C > 500 °C > 400 °C > 300 °C. Finally, the amount of adsorbed P by activated biochar at different ratios of biochar to ZnCl2 appeared in the order 1:3 ≒ 1:1 > 3:1. As a result, the optimum ratio of biochar to ZnCl2 and pyrolysis temperature were found to be 1:1 and 600 °C for P adsorption, respectively. The maximum P adsorption capacity by activated biochar using ZnCl2 (15,460 mg kg(-1)) was higher than that of typical biochar, as determined by the Langmuir adsorption isotherm. Therefore, the ZnCl2 activation of sesame straw biochar was suitable for the preparation of activated biochar for P adsorption.

  20. New treatment method for boron in aqueous solutions using Mg-Al layered double hydroxide: Kinetics and equilibrium studies.

    PubMed

    Kameda, Tomohito; Oba, Jumpei; Yoshioka, Toshiaki

    2015-08-15

    Mg-Al layered double hydroxides (LDHs) intercalated with NO3(-) (NO3 · Mg - Al LDHs) and with Cl(-) (Cl · Mg - Al LDHs) were found to take up boron from aqueous solutions. Boron was removed by anion exchange of B(OH)4(-) in solution with NO3(-) and Cl(-) intercalated in the interlayer of the LDH. Using three times the stoichiometric quantity of NO3 · Mg-Al LDH, the residual concentration of B decreased from 100 to 1.9 mg L(-1) in 120 min. Using five times the stoichiometric quantity of Cl · Mg - Al LDH, the residual concentration of B decreased from 100 to 5.6 mg L(-1) in 120 min. It must be emphasized that, in both cases, the residual concentration of B was less than the effluent standards in Japan (10 mg L(-1)). The rate-determining step of B removal by the NO3 · Mg - Al and Cl · Mg - Al LDHs was found to be chemical adsorption involving anion exchange of B(OH)4(-) with intercalated NO3(-) and Cl(-). The removal of B was well described by a pseudo second-order kinetic equation. The adsorption of B by NO3 · Mg - Al LDH and Cl · Mg - Al LDH followed a Langmuir-type adsorption. The values of the maximum adsorption and the equilibrium adsorption constant were 3.6 mmol g(-1) and 1.7, respectively, for NO3 · Mg - Al LDH, and 3.8 mmol g(-1) and 0.7, respectively, for Cl · Mg-Al LDH. The B(OH)4(-) in B(OH)4 · Mg - Al LDH produced by removal of B was found to undergo anion exchange with NO3(-) and Cl(-) in solution. The NO3 · Mg - Al and Cl · Mg - Al LDHs obtained after this regeneration treatment were able to remove B from aqueous solutions, indicating the possibility of recycling NO3 · Mg - Al and Cl · Mg - Al LDHs for B removal. PMID:25827268

  1. New treatment method for boron in aqueous solutions using Mg-Al layered double hydroxide: Kinetics and equilibrium studies.

    PubMed

    Kameda, Tomohito; Oba, Jumpei; Yoshioka, Toshiaki

    2015-08-15

    Mg-Al layered double hydroxides (LDHs) intercalated with NO3(-) (NO3 · Mg - Al LDHs) and with Cl(-) (Cl · Mg - Al LDHs) were found to take up boron from aqueous solutions. Boron was removed by anion exchange of B(OH)4(-) in solution with NO3(-) and Cl(-) intercalated in the interlayer of the LDH. Using three times the stoichiometric quantity of NO3 · Mg-Al LDH, the residual concentration of B decreased from 100 to 1.9 mg L(-1) in 120 min. Using five times the stoichiometric quantity of Cl · Mg - Al LDH, the residual concentration of B decreased from 100 to 5.6 mg L(-1) in 120 min. It must be emphasized that, in both cases, the residual concentration of B was less than the effluent standards in Japan (10 mg L(-1)). The rate-determining step of B removal by the NO3 · Mg - Al and Cl · Mg - Al LDHs was found to be chemical adsorption involving anion exchange of B(OH)4(-) with intercalated NO3(-) and Cl(-). The removal of B was well described by a pseudo second-order kinetic equation. The adsorption of B by NO3 · Mg - Al LDH and Cl · Mg - Al LDH followed a Langmuir-type adsorption. The values of the maximum adsorption and the equilibrium adsorption constant were 3.6 mmol g(-1) and 1.7, respectively, for NO3 · Mg - Al LDH, and 3.8 mmol g(-1) and 0.7, respectively, for Cl · Mg-Al LDH. The B(OH)4(-) in B(OH)4 · Mg - Al LDH produced by removal of B was found to undergo anion exchange with NO3(-) and Cl(-) in solution. The NO3 · Mg - Al and Cl · Mg - Al LDHs obtained after this regeneration treatment were able to remove B from aqueous solutions, indicating the possibility of recycling NO3 · Mg - Al and Cl · Mg - Al LDHs for B removal.

  2. CAPSULE REPORT: AQUEOUS MERCURY TREATMENT

    EPA Science Inventory

    This report describes established technologies and identifies evolving methods for treating aqueous mercury. The information provided encompasses full-, pilot- and bench-scale treatment results as presented in the technical literature. The report describes alternative technologi...

  3. Determination of the acid dissociation constant of the biosurfactant monorhamnolipid in aqueous solution by potentiometric and spectroscopic methods.

    PubMed

    Lebrón-Paler, Ariel; Pemberton, Jeanne E; Becker, Bridget A; Otto, William H; Larive, Cynthia K; Maier, Raina M

    2006-11-15

    The acid dissociation constant in water for a monorhamnolipid mixture extracted from Pseudomonas aeruginosa ATCC 9027 has been determined using potentiometry and two spectroscopic approaches at concentrations below and above the critical micelle concentration (cmc). Potentiometric titrations resulted in pKa values ranging from 4.28 +/- 0.16 to 5.50 +/- 0.06 depending on concentration. 1H NMR spectrochemical titrations at concentrations below the cmc revealed a pKa value of 4.39 +/- 0.06. ATR-FT-IR spectrochemical titrations on solutions well above the cmc gave a pKa value of 4.84 +/- 0.05. The value of 4.28 for the free rhamnolipid molecule for concentrations below the cmc differs markedly from that reported previously. However, the pKa of 5.50 for surface-adsorbed and solution aggregates correlates closely to that previously reported. Differences in these pKa values are rationalized in terms of the pH- and concentration-dependent aggregation behavior of rhamnolipids in aqueous solution.

  4. GC/MS method for determining carbon isotope enrichment and concentration of underivatized short-chain fatty acids by direct aqueous solution injection of biogas digester samples.

    PubMed

    Mulat, Daniel Girma; Feilberg, Anders

    2015-10-01

    In anaerobic digestion of organic matter, several metabolic pathways are involved during the simultaneous production and consumption of short-chain fatty acids (SCFA) in general and acetate in particular. Understanding the role of each pathway requires both the determination of the concentration and isotope enrichment of intermediates in conjunction with isotope labeled substrates. The objective of this study was to establish a rapid and simple GC/MS method for determining the isotope enrichment of acetate and concentration of underivatized short-chain fatty acids (SCFA) in biogas digester samples by direct liquid injection of acidified aqueous samples. Sample preparation involves only acidification, centrifugation and filtration of the aqueous solution followed by direct injection of the aqueous supernatant solution onto a polar column. With the sample preparation and GC/MS conditions employed, well-resolved and sharp peaks of underivatized SCFA were obtained in a reasonably short time. Good recovery (96.6-102.3%) as well as low detection (4-7 µmol/L) and quantification limits (14-22 µmol/L) were obtained for all the 6 SCFA studied. Good linearity was achieved for both concentration and isotope enrichment measurement with regression coefficients higher than 0.9978 and 0.9996, respectively. The method has a good intra- and inter-day precision with a relative standard deviation (RSD) below 6% for determining the tracer-to-tracee ratio (TTR) of both [2-(13)C]acetate and [U-(13)C]acetate. It has also a good intra- and inter-day precision with a RSD below 6% and 5% for determining the concentration of standard solution and biogas digester samples, respectively. Acidification of biogas digester samples with oxalic acid provided the low pH required for the protonation of SCFA and thus, allows the extraction of SCFA from the complex sample matrix. Moreover, oxalic acid was the source of formic acid which was produced in the injector set at high temperature. The produced

  5. Active seismic monitoring of changes of the reflection response of a crystalline shear zone due to fluid injection in the crust at the Continental Deep Drilling Site, Germany

    NASA Astrophysics Data System (ADS)

    Beilecke, T.; Kurt, B.; Stefan, B.

    2005-12-01

    In theory and in the laboratory variations of the hydraulic pressure can be detected with seismic methods: A lowering of the hydraulic pressure leads to the closure of micro-cracks within the rock (increase of the differential or effective pressure). Subsequently, the seismic velocities increase. An increase of the hydraulic pressure leads to reverse seismic effects. Consequently, seismic impedance contrasts and associated reflection amplitudes vary in the case of a propagating fluid pressure front in a rock matrix with inhomogeneous permeability - as is the case at shear zones. The largest amplitude changes can be expected with vertical ray inclination on the impedance contrast. Generally, the expected effects are small however (Kaselow, 2004). The practical utilization of active seismics for the detection of pressure changes at large scale in hard rock is currently being studied at the Continental Deep Drilling Site (KTB). The injection of water (200 l/min) in a depth of about 4000 m into the so-called SE2 shear zone in the KTB pilot hole was monitored with active seismics between May 2004 and April 2005. The core of the experiment layout is a fixed 5-arm geophone array consisting of 24 3-component geophones, buried at about 70 cm depth. The source signal is a vertical vibrator sweep of 30 s length with the spectrum 30-120 Hz. The signal is sent into the ground 32 times during each cycle, detected with the array and recorded separately for each geophone channel, without prior correlation with the source signal. This allows maximum post-processing with seismic processing and analysis tools and especially permits the use of array properties to increase the signal-to-noise ratio. Critical parameters of the experiment are the repeatability of the source signal as well as the stability of the receiver properties. Another pivot is the hydraulic pressure and its distribution built up within the rock matrix. Estimations based on model calculations show that a change of

  6. A novel method of non-violent dissolution of sodium metal in a concentrated aqueous solution of Epsom salt

    NASA Astrophysics Data System (ADS)

    Lakshmanan, A. R.; Prasad, M. V. R.; Ponraju, D.; Krishnan, H.

    2004-10-01

    A new technique of non-violent and fast dissolution of sodium metal in a concentrated aqueous solution of Epsom salt (MgSO4.7H2O) at room temperature (RT) has been developed. The dissolution process is mildly exothermic but could be carried out even in a glass beaker in air under swift stirring condition. The reaction products consist of mixed salts of MgSO4 and Na2SO4 as well as Mg(OH)2 which are only mildly alkaline and hence are non-corrosive and non-hazardous unlike NaOH. A 50 mL solution having Epsom salt concentration of 2 M was found to give the optimal composition for disposal of 1 g of sodium. Supersaturated (>2.7 M), as well as dilute (<1.1 M) solutions, however, cause violent reactions and hence should be avoided. Repeated sodium dissolution in Epsom solution produced a solid waste of 4.7 g per g of sodium dissolved which is comparable with the waste (4 g) produced in 8 M NaOH solution. A 1.4 M Epsom solution sprayed with a high-pressure jet cleaner at RT in air easily removed the sodium blocked inside a metal pipe made of mild steel. The above jet also dissolved peacefully residual sodium collected on the metal tray after a sodium fire experiment. No sodium fire or explosion was observed during this campaign. The Epsom solution spray effectively neutralized the minor quantity of sodium aerosol produced during this campaign. This novel technique would hence be quite useful for draining sodium from fast breeder reactor components and bulk processing of sodium as well as for sodium fire fighting.

  7. Structural, chemical and optical evaluation of Cu-doped ZnO nanoparticles synthesized by an aqueous solution method

    SciTech Connect

    Iribarren, A.; Hernández-Rodríguez, E.; Maqueira, L.

    2014-12-15

    Highlights: • Cu-doped ZnO nanoparticles obtained by chemical synthesis. • Substitutional or interstitial Cu into ZnO lead specific structural, chemical, and optical changes. • Incorporation efficiency of Cu atoms in ZnO as a function of the Cu concentration in the precursor dissolution. - Abstract: In this work a study of ZnO and Cu-doped ZnO nanoparticles obtained by chemical synthesis in aqueous media was carried out. Structural analysis gave the dominant presence of wurtzite ZnO phase forming a solid solution Zn{sub 1−x}Cu{sub x}O. For high Cu doping CuO phase is also present. For low Cu concentration the lattice shrinks due to Cu atoms substitute Zn atoms. For high Cu concentration the lattice enlarges due to predominance of interstitial Cu. From elemental analysis we determined and analyzed the incorporation efficiency of Cu atoms in Zn{sub 1−x}Cu{sub x}O as a function of the Cu concentration in the precursor dissolution. Combining structural and chemical results we described the Cu/Zn precursor concentrations r{sub w} in which the solid solution of Cu in ZnO is predominant. In the region located at r{sub w} ≈ 0.2–0.3 it is no longer valid. For Cu/Zn precursor concentration r{sub w} > 0.3 interstitial Cu dominates, and some amount of copper oxide appears. As the Cu concentration increases, the effective size of nanoparticles decreases. Photoluminescence (PL) measurements of the Cu-doped ZnO nanoparticles were carried out and analyzed.

  8. Validation of method for determination of different classes of pesticides in aqueous samples by dispersive liquid-liquid microextraction with liquid chromatography-tandem mass spectrometric detection.

    PubMed

    Caldas, Sergiane Souza; Costa, Fabiane Pinho; Primel, Ednei Gilberto

    2010-04-14

    In this study, a simple, rapid and efficient method has been developed for the extraction and preconcentration of different classes of pesticides, carbofuran (insecticide), clomazone (herbicide) and tebuconazole (fungicide) in aqueous samples by dispersive liquid-liquid microextraction (DLLME) coupled with liquid chromatography-tandem mass spectrometric detection. Some experimental parameters that influence the extraction efficiency, such as the type and volume of the disperser solvents and extraction solvents, extraction time, speed of centrifugation, pH and addition of salt were examined and optimized. Under the optimum conditions, the recoveries of pesticides in water at spiking levels between 0.02 and 2.0 microg L(-1) ranged from 62.7% to 120.0%. The relative standard deviations varied between 1.9% and 9.1% (n=3). The limits of quantification of the method considering a 50-fold preconcentration step were 0.02 microg L(-1). The linearity of the method ranged from 1.0 to 1000 microg L(-1) for all compounds, with correlation coefficients varying from 0.9982 to 0.9992. Results show that the method we propose can meet the requirements for the determination of pesticides in water samples. The comparison of this method with solid-phase extraction indicates that DLLME is a simple, fast, and low-cost method for the determination of pesticides in natural waters.

  9. Flower-shaped ZnO nanocrystallite aggregates synthesized through a template-free aqueous solution method for dye-sensitized solar cells

    SciTech Connect

    Chang, Wei-Chen; Chen, Hung-Shuo; Yu, Wan-Chin

    2015-01-05

    Hierarchically structured flower-shaped aggregates composed of ZnO nanocrystals were synthesized through a template-free aqueous solution method. The synthesized nanocrystallite aggregates were demonstrated to be promising photoanode materials for dye-sensitized solar cells (DSSCs). Compared with commercially available ZnO nanoparticles (ZnONPs), the flower-like aggregates (ZnONFs), each having an overall dimension of 400–600 nm, exhibited similar dye loading but higher light-scattering ability, which led to a substantial increase in the light-harvesting efficiency of resulting cells. The unique morphology of ZnONFs also boosted the absorbed photon-to-electric current generation efficiency. Consequently, DSSCs constructed from ZnONFs showed significantly improved photocurrent and achieved an overall conversion efficiency of 4.42%, which was 47% higher than that attained by ZnONP-based cells.

  10. Interfacial degradation effects of aqueous solution-processed molybdenum trioxides on the stability of organic solar cells evaluated by a differential method

    SciTech Connect

    Lou, Yan-Hui; Wang, Zhao-Kui E-mail: lsliao@suda.edu.cn; Yuan, Da-Xing; Liao, Liang-Sheng E-mail: lsliao@suda.edu.cn; Okada, Hiroyuki

    2014-09-15

    The authors investigate the influence of two hole interfacial materials poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) and aqueous solution-processed MoO{sub 3} (sMoO{sub 3}) on cell stability. sMoO{sub 3}-based device demonstrated obviously improved stability compared to PEDOT:PSS-based one. Current-voltage characteristics analysis is carried out to investigate the effect of the hole interfacial layers on the cell stability. The formation of additional trap states at the interfaces between the hole interfacial layer and the active layer in degraded devices is verified by a differential method. Improved cell stability is attributed to a relatively stable sMoO{sub 3} interfacial layer compared to PEDOT:PSS by comparing their different trap states distributions.

  11. Fluid-Injection Tool for Inaccessible Areas

    NASA Technical Reports Server (NTRS)

    Myers, J. E.

    1982-01-01

    New tool injects liquids or gases into narrow crevices. Can be used to apply caulking and waterproofing compounds, adhesives, detergent, undercoats and oil and to aerate hard-to-reach places. Nozzle can reach into opening 1/32 inch wide to depth of more than 4 inches. Although thin, device is rigid and strong.

  12. Environmental remediation by an integrated microwave/ UV-illumination method. 1. Microwave-assisted degradation of rhodamine-B dye in aqueous TiO2 dispersions.

    PubMed

    Horikoshi, Satoshi; Hidaka, Hisao; Serpone, Nick

    2002-03-15

    The photocatalytic decomposition of the cationic rhodamine-B (RhB) dye was examined in aqueous TiO2 dispersions using an integrated microwave/UV-illumination (PD/MW) method. This procedure proved to be superior in the degradation of the dye than the TiO2 photocatalytic degradative method alone. With few exceptions, the integrated PD/MW method also proved superior for other chemical systems. The greater efficacy of the PD/MW technique appears to be the result of the following two considerations: (i) there is enhanced formation of reactive oxygen species (.OH radicals), as attested to by DMPO spin-trap ESR methods and their attack on the dye; and although speculative at this time, (ii) the activity of bulk water or the TiO2 particle surface is somehow affected by microwave radiation. The greater efficacy of the PD/MW degradation method was also observed at low concentrations of molecular oxygen and at low radiant excitance of the light source. A brief mechanistic description is given on the basis of results obtained on the two model compounds, (i) benzoic acid and (ii) pyronin-B dye.

  13. A non-aqueous solid phase extraction method for alkaloid enrichment and its application in the determination of hyoscyamine and scopolamine.

    PubMed

    Long, Zhen; Wang, Chaoran; Guo, Zhimou; Zhang, Xiuli; Nordahl, Lilly; Zeng, Jing; Zeng, Jianguo; Liang, Xinmiao

    2012-03-21

    A non-aqueous solid phase extraction (SPE) method utilizing silica based strong cation exchange (SCX) was developed and optimized for the enrichment of alkaloids. In this method, silica based SCX SPE columns were used for the elimination of non-alkaloid compounds and the preconcentration of alkaloids from the extracts. Mass spectrometry was employed to analyze the alkaloid-enriched fraction, and results showed that the SPE method developed in this study was effective for the removal of non-alkaloids. Then, this pretreatment method was combined with high performance liquid chromatography for the quantification of scopolamine and hyoscyamine from Scopolia tangutica Maxim. The recoveries of scopolamine and (-)-hyoscyamine were 98.51% and 91.12%, respectively. Relative standard deviation values were 1.4% for scopolamine and 1.6% for (-)-hyoscyamine. The linearity was good in the 0.01-0.8 mg mL(-1) range for hyoscyamine and 0.01-0.4 mg mL(-1) range for scopolamine.

  14. Ultrasensitive and rapid screening of mercury(II) ions by dual labeling colorimetric method in aqueous samples and applications in mercury-poisoned animal tissues.

    PubMed

    Deng, Yi; Wang, Xin; Xue, Feng; Zheng, Lei; Liu, Jian; Yan, Feng; Xia, Fan; Chen, Wei

    2015-04-01

    Rapid and ultrasensitive detection of trace heavy metal mercury(II) ions (Hg(2+)) are of significant importance due to the induced serious risks for environment and human health. This presented article reports the gold nanoparticle-based dual labeling colorimetric method (Dual-COLO) for ultrasensitive and rapid detection of Hg(2+) using the specific thymine-Hg(2+)-thymine (T-Hg(2+)-T) as recognition system and the dual labeling strategy for signal amplification. Both qualitative and quantitative detections of Hg(2+) are achieved successfully in aqueous samples. More importantly, the achieved detection limit of 0.005 ng mL(-1) (0.025 nM) without any instruments is very competitive to other rapid detection methods even ICP-MS based methods. This Dual-COLO method is also applied directly for real water sample monitoring and, more importantly, applied in analysis of mercury poisoned animal tissues and body fluidic samples, indicating a potentially powerful and promising tool for environmental monitoring and food safety control.

  15. Coal desulfurization by aqueous chlorination

    NASA Technical Reports Server (NTRS)

    Kalvinskas, J. J.; Vasilakos, N.; Corcoran, W. H.; Grohmann, K.; Rohatgi, N. K. (Inventor)

    1982-01-01

    A method of desulfurizing coal is described in which chlorine gas is bubbled through an aqueous slurry of coal at low temperature below 130 degrees C., and at ambient pressure. Chlorinolysis converts both inorganic and organic sulfur components of coal into water soluble compounds which enter the aqueous suspending media. The media is separated after chlorinolysis and the coal dechlorinated at a temperature of from 300 C to 500 C to form a non-caking, low-sulfur coal product.

  16. Aqueous Based Semiconductor Nanocrystals.

    PubMed

    Jing, Lihong; Kershaw, Stephen V; Li, Yilin; Huang, Xiaodan; Li, Yingying; Rogach, Andrey L; Gao, Mingyuan

    2016-09-28

    This review summarizes traditional and recent nonconventional, bioinspired, methods for the aqueous synthesis of colloidal semiconductor quantum dots (QDs). The basic chemistry concepts are critically emphasized at the very beginning as these are strongly correlated with the selection of ligands and the optimal formation of aqueous QDs and their more sophisticated structures. The synergies of biomimetic and biosynthetic methods that can combine biospecific reactivity with the robust and strong optical responses of QDs have also resulted in new approaches to the synthesis of the nanoparticles themselves. A related new avenue is the recent extension of QD synthesis to form nanoparticles endowed with chiral optical properties. The optical characteristics of QD materials and their advanced forms such as core/shell heterostructures, alloys, and doped QDs are discussed: from the design considerations of optical band gap tuning, the control and reduction of the impact of surface traps, the consideration of charge carrier processes that affect emission and energy and charge transfer, to the impact and influence of lattice strain. We also describe the considerable progress in some selected QD applications such as in bioimaging and theranostics. The review concludes with future strategies and identification of key challenges that still need to be resolved in reaching very attractive, scalable, yet versatile aqueous syntheses that may widen the scope of commercial applications for semiconductor nanocrystals. PMID:27586892

  17. Study of preparation method and oxidization/reduction effect on the performance of nickel-cerium oxide catalysts for aqueous-phase reforming of ethanol

    NASA Astrophysics Data System (ADS)

    Roy, B.; Leclerc, C. A.

    2015-12-01

    The effect of preparation method and oxidation state of the active metal on the catalytic activity of Ni-Ce-O catalysts was studied for aqueous phase reforming of ethanol. A sol-gel (SG) route and a solution combustion synthesis (SCS) method were used for the preparation of 10 wt% Ni loaded catalysts. The catalytic activity of three groups of catalysts; reduced at 425 °C (HR, metallic Ni), reduced at 1000 °C (FR, metallic Ni), and not reduced (NR, as NiO) were tested at different operating conditions. The difference in the metal particle sizes, governed by the preparation method, affects the catalytic efficiency most, not the reduced or oxidized state of Ni. The SG samples were superior for ethanol conversion and selectivity for H2 and CO2 compared to the SCS samples. The X-ray photoelectron spectroscopy (XPS) analysis of the samples demonstrated that the relative ratio of Ce2O3 to CeO2 increased inside the reactor. While Ni doping increases oxygen mobility in the Ce-O lattice, Ce3+ converts Ni2+ to metallic Ni inside the reactor. This can explain why the reduction stage for Ni-Ce-O system in APR is irrelevant. Higher oxygen mobility through the support helps oxidation of CO to CO2 leading to improved catalytic performance.

  18. A sensitive spectrofluorimetric method for the quantification of melamine residue in milk powder using the Mannich reaction in aqueous solutions.

    PubMed

    Rima, Jamil; Assaker, Karine; El Omar, Fawaz; karim, Chawki bou

    2013-11-15

    The objective of this study was to develop a spectrofluorimetric method for the quantitative determination of melamine. The method was based on the complexation of melamine with a mixture of formaldehyde and chemicals including a ketone group, as described by the Mannich reaction. The complex was determined by spectrofluorimetric measurement as it is characterized by specific spectroscopic properties that are related to the chromophore of the ketone compounds. 1,3-Diphenylpropane-1,3-dione (DPPD) was tested as a ketone compound. The fluorescence spectrum of the complex presented a maximum of absorption at 325 nm.A quenching of the fluorescence occurred when melamine was added into the solution. The kinetic of fluorescence quenching was followed to determine quantitatively the melamine concentration. An internal standard was added to quantify melamine. The method was tested to determine the level of melamine in contaminated milk powder. The recovery value was 97% and the limit of detection was 0.007 μg mL(-1.)

  19. The Switching/gaussian Method for Polarizable Continuum Models with Applications to Aqueous Molecular Dynamics and Vibrational Spectra

    NASA Astrophysics Data System (ADS)

    Lange, Adrian W. G.; Herbert, John M.

    2010-06-01

    We describe the recently-developed Switching/Gaussian (SWIG) formalism for polarizable continuum models (PCMs) in electronic structure theory and QM/MM calculations. Existing PCM implementations are well-established, yet still exhibit Coulomb singularities and/or discontinuities in potential energy surfaces, which result from the finite-element discretization of the solute--continuum interface. Our revised implementation eliminates these problems. We illustrate the robustness this approach using ab initio molecular dynamics and vibrational spectra calculations, for which existing PCM implementations fail. Furthermore, we present the extension of SWIG to unprecedentedly large systems, making it a viable implicit solvation method even for molecular mechanics calculations of biological macromolecules.

  20. Stimuli-responsive coacervate induced in binary functionalized poly(N-isopropylacrylamide) aqueous system and novel method for preparing semi-ipn microgel using the coacervate.

    PubMed

    Maeda, Tomohiro; Akasaki, Yusuke; Yamamoto, Kazuya; Aoyagi, Takao

    2009-08-18

    We describe a novel method for preparing a stimuli-responsive semi-interpenetrating polymer network (semi-IPN) hydrogel microsphere using a thermoresponsive-type coacervation. The coacervate droplets were formed in the two-component nonionic poly(N-isopropylacrylamide-co-2-hydroxyisopropylacrylamide) (poly(NIPAAm-co-HIPAAm)) and ionic poly(NIPAAm-co-2-carboxyisopropylacrylamide) (poly(NIPAAm-co-CIPAAm)) aqueous system by heating the solution above the lower critical solution temperature. The resulting coacervate droplets included both kinds of polymer chains. Divinyl sulfone, which cross-links the hydroxyl groups of the poly(NIPAAm-co-HIPAAm), was added to the coacervate droplets. In this way, the stimuli-responsive semi-IPN hydrogel microsphere consisting of the poly(NIPAAm-co-HIPAAm) gel matrix and the linear poly(NIPAAm-co-CIPAAm) chains could be prepared, and their sizes were relatively homogeneous. That is, by utilizing the thermoresponsive coacervate droplets induced in the binary system, we could successfully prepare the fine stimuli-responsive semi-IPN hydrogel microsphere and it was prepared in a simple and easy method without any additives.

  1. Influence of Capping Ligand and Synthesis Method on Structure and Morphology of Aqueous Phase Synthesized CuInSe2 Nanoparticles

    NASA Astrophysics Data System (ADS)

    Ram Kumar, J.; Ananthakumar, S.; Moorthy Babu, S.

    2016-09-01

    A facile route to synthesize copper indium diselenide (CuInSe2) nanoparticles in aqueous medium was developed using mercaptoacetic acid (MAA) as capping agent. Two different mole ratios (5 and 10) of MAA were used to synthesize CuInSe2 nanoparticles at room temperature, as well as hydrothermal (high temperature) method. Powder x-ray diffraction analysis reveals that the nanoparticles exhibit chalcopyrite phase and the crystallinity increases with increasing the capping ratio. Raman analysis shows a strong band at 233 cm-1 due to the combination of B2 (E) modes. Broad absorption spectra were observed for the synthesized CuInSe2 nanoparticles. The effective surface capping by MAA on the nanoparticles surface was confirmed through attenuated total reflection-Fourier transform infrared spectral analysis. The thermal stability of the synthesized samples was analyzed through thermogravimetric analysis-differential scanning calorimetry. The change in morphology of the synthesized samples was analyzed through scanning electron microscope and it shows that the samples prepared at room temperature are spherical in shape, whereas hydrothermally synthesized samples were found to have nanorod- and nanoflake-like structures. Transmission electron microscope analysis further indicates larger grains for the hydrothermally prepared samples with 10 mol ratio of MAA. Comparative analyses were made for synthesizing CuInSe2 nanoparticles by two different methods to explore the role of ligand and influence of temperature.

  2. Quantitative 31P NMR for Simultaneous Trace Analysis of Organophosphorus Pesticides in Aqueous Media Using the Stir Bar Sorptive Extraction Method

    NASA Astrophysics Data System (ADS)

    Ansari, S.; Talebpour, Z.; Molaabasi, F.; Bijanzadeh, H. R.; Khazaeli, S.

    2016-09-01

    The analysis of pesticides in water samples is of primary concern for quality control laboratories due to the toxicity of these compounds and their associated public health risk. A novel analytical method based on stir bar sorptive extraction (SBSE), followed by 31P quantitative nuclear magnetic resonance (31P QNMR), has been developed for simultaneously monitoring and determining four organophosphorus pesticides (OPPs) in aqueous media. The effects of factors on the extraction efficiency of OPPs were investigated using a Draper-Lin small composite design. An optimal sample volume of 4.2 mL, extraction time of 96 min, extraction temperature of 42°C, and desorption time of 11 min were obtained. The results showed reasonable linearity ranges for all pesticides with correlation coefficients greater than 0.9920. The limit of quantification (LOQ) ranged from 0.1 to 2.60 mg/L, and the recoveries of spiked river water samples were from 82 to 94% with relative standard deviation (RSD) values less than 4%. The results show that this method is simple, selective, rapid, and can be applied to other sample matrices.

  3. Use of the Relaxometry Technique for Quantification of Paramagnetic Ions in Aqueous Solutions and a Comparison with Other Analytical Methods

    PubMed Central

    Burato, Juliana Soares da Silva; Silva Lobo, Carlos Manuel; Colnago, Luiz Alberto

    2016-01-01

    We have demonstrated that the relaxometry technique is very efficient to quantify paramagnetic ions during in situ electrolysis measurements. Therefore, the goal of this work was to validate the relaxometry technique in the determination of the concentration of the ions contained in electrolytic solutions, Cu2+, Ni2+, Cr3+, and Mn2+, and compare it with other analytical methods. Two different NMR spectrometers were used: a commercial spectrometer with a homogeneous magnetic field and a home-built unilateral sensor with an inhomogeneous magnetic field. Without pretreatment, manganese ions do not have absorption bands in the UV-Visible region, but it is possible to quantify them using relaxometry (the limit of quantification is close to 10−5 mol L−1). Therefore, since the technique does not require chemical indicators and is a cheap and robust method, it can be used as a replacement for some conventional quantification techniques. The relaxometry technique could be applied to evaluate the corrosion of metallic surfaces. PMID:27293437

  4. Direct injection method for HPLC/MS/MS analysis of acrylamide in aqueous solutions: application to adsorption experiments.

    PubMed

    Mnif, Ines; Hurel, Charlotte; Marmier, Nicolas

    2015-05-01

    Polyacrylamides are polymers used in many fields and represent the main source of release of the highly toxic acrylamide in the environment. In this work, a simple, rapid, and sensitive analytical method was developed with HPLC/MS/MS and direct injection for acrylamide analysis in water and adsorption samples. AFNOR standards NF T90-210 and NF T90-220 were used for the analytical method validation and uncertainty estimation. Limit of quantification (LOQ) for acrylamide was 1 μg/L, and accuracy was checked at three acrylamide levels (1, 6, and 10 μg/L). Uncertainties were estimated at 34.2, 22, and 12.4 % for acrylamide concentrations at LOQ, 6 μg/L, and 10 μg/L, respectively. Acrylamide adsorption on clays (kaolinite, illite) and sludge was then studied as a function of pH, time, and acrylamide concentrations. Acrylamide adsorption on kaolinite, illite, and sludge was found to be very weak since adsorption percentages were inferior to 10 %, whatever the pH value and the initial acrylamide concentration. The low affinity of acrylamide for clays and sludge is likely due to its hydrophilic property, small size, and charge neutrality.

  5. Comparison of static and dynamic methods of treatment of anharmonicity for the vibrational study of isolated and aqueous forms of guanine

    NASA Astrophysics Data System (ADS)

    Thicoipe, Sandrine; Carbonniere, Philippe; Pouchan, Claude

    2014-01-01

    This theoretical study provides the anharmonic vibrational wavenumbers of isolated and aqueous guanine. They were performed at the DFT B3LYP/6-31+G(d,p) level of theory using two different ways for the treatment of anharmonicity: time-independent (VPT2) and time-dependent (molecular dynamics) approaches. The wavenumbers obtained are compared to experimental data for isolated and aqueous forms: the VPT2 approach is slightly better than MD, especially for the determination of stretching and wagging (NH) motions. Finally, the structural model of solvatation used for aqueous guanine which combines an explicit solvent model with a polarizable continuum model (PCM) was validated.

  6. An improved method for estimating R-phycoerythrin and R-phycocyanin contents from crude aqueous extracts of Porphyra (Bangiales, Rhodophyta)

    PubMed Central

    Neefus, Christopher D.

    2006-01-01

    One frequently-cited method for determining phycoerythrin (PE) and phycocyanin (PC) contents from crude aqueous extracts of red seaweeds utilizes peaks and troughs of absorbance spectra. The trough absorbance values are used to establish a linear or logarithmic baseline attributable to background scatter of particulate cellular debris not removed by centrifugation. Pigment contents are calculated by subtracting baseline values from PE and PC absorbance peaks. The baseline correction is intended to make the method independent of centrifugation time and/or speed. However, when crude extracts of Porphyra were analyzed using this protocol, R-PE and R-PC estimates were significantly affected by centrifugation time, suggesting that the method was not reliable for the genus. The present study has shown that with sufficient centrifugation, background scatter in Porphyra extracts can be removed, the remaining spectrum representing the overlapping absorbance peaks of water-soluble pigments in the extract. Using fourth derivative analysis of Porphyra extract absorbance spectra, peaks corresponding to chlorophyll, R-PE, R-PC, and allophycocyanin (APC) were identified. Dilute solutions of purified R-PE, R-PC and chlorophyll were scanned separately to identify spectral overlaps and develop new equations for phycobilin quantification. The new equations were used to estimate R-PE and R-PC contents of Porphyra extracts and purified R-PE, R-PC and chlorophyll solutions were mixed according to concentrations corresponding to the sample estimates. Absorbances and fourth derivative spectra of the sample extract and purified pigment mixtures were compared and found to coincide. The newly derived equations are more accurate for determining R-PE and R-PC of Porphyra than previously published methods. PMID:19396349

  7. Characterisation and optimisation of a sample preparation method for the detection and quantification of atmospherically relevant carbonyl compounds in aqueous medium

    NASA Astrophysics Data System (ADS)

    Rodigast, M.; Mutzel, A.; Iinuma, Y.; Haferkorn, S.; Herrmann, H.

    2015-06-01

    Carbonyl compounds are ubiquitous in the atmosphere and either emitted primarily from anthropogenic and biogenic sources or they are produced secondarily from the oxidation of volatile organic compounds. Despite a number of studies about the quantification of carbonyl compounds a comprehensive description of optimised methods is scarce for the quantification of atmospherically relevant carbonyl compounds. The method optimisation was conducted for seven atmospherically relevant carbonyl compounds including acrolein, benzaldehyde, glyoxal, methyl glyoxal, methacrolein, methyl vinyl ketone and 2,3-butanedione. O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was used as derivatisation reagent and the formed oximes were detected by gas chromatography/mass spectrometry (GC/MS). With the present method quantification can be carried out for each carbonyl compound originating from fog, cloud and rain or sampled from the gas- and particle phase in water. Detection limits between 0.01 and 0.17 μmol L-1 were found, depending on carbonyl compounds. Furthermore, best results were found for the derivatisation with a PFBHA concentration of 0.43 mg mL-1 for 24 h followed by a subsequent extraction with dichloromethane for 30 min at pH = 1. The optimised method was evaluated in the present study by the OH radical initiated oxidation of 3-methylbutanone in the aqueous phase. Methyl glyoxal and 2,3-butanedione were found to be oxidation products in the samples with a yield of 2% for methyl glyoxal and 14% for 2,3-butanedione after a reaction time of 5 h.

  8. Removal of strontium (Sr2+) from aqueous solutions with titanosilicates obtained by the sol-gel method.

    PubMed

    Oleksiienko, Olga; Levchuk, Irina; Sitarz, Maciej; Meleshevych, Svitlana; Strelko, Volodymyr; Sillanpää, Mika

    2015-01-15

    Titanosilicates (TiSis) were synthesized from pure and technical precursors by the sol-gel method. X-ray diffraction (XRD) studies of TiSi identified amorphous phases. The Brunauer, Emmett and Teller (BET) surface area of TiSis obtained from pure and technical precursors measured using the low-temperature nitrogen adsorption/desorption technique were 270.3 and 158.7 m(2) g(-1), respectively. Micro-mesopore and micro- meso- macropore structures were attributed to TiSi prepared from pure and technical precursors, correspondingly. TiSis mass, solution pH, contact time, initial Sr(2+) concentration, temperature and background solution were investigated for their effect on sorption properties. TiSis were observed to have a high affinity for strontium in the pH range of 4-12. Strontium adsorption isotherms were established and fitted to the Langmuir, Freundlich, Redlich-Peterson, Sips and Toth models. Pseudo-first and pseudo-second models were used to describe experimental kinetic data. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) data for TiSis were collected before and after adsorption. Heterophase was observed on the surfaces of both types of TiSi material after Sr(2+) uptake. The mechanism of Sr(2+) sorption on titanosilicates was suggested.

  9. Theoretical and experimental studies on freezing point depression and vapor pressure deficit as methods to measure osmotic pressure of aqueous polyethylene glycol and bovine serum albumin solutions.

    PubMed

    Kiyosawa, Keitaro

    2003-05-01

    For survival in adverse environments where there is drought, high salt concentration or low temperature, some plants seem to be able to synthesize biochemical compounds, including proteins, in response to changes in water activity or osmotic pressure. Measurement of the water activity or osmotic pressure of simple aqueous solutions has been based on freezing point depression or vapor pressure deficit. Measurement of the osmotic pressure of plants under water stress has been mainly based on vapor pressure deficit. However, differences have been noted for osmotic pressure values of aqueous polyethylene glycol (PEG) solutions measured by freezing point depression and vapor pressure deficit. For this paper, the physicochemical basis of freezing point depression and vapor pressure deficit were first examined theoretically and then, the osmotic pressure of aqueous ethylene glycol and of PEG solutions were measured by both freezing point depression and vapor pressure deficit in comparison with other aqueous solutions such as NaCl, KCl, CaCl(2), glucose, sucrose, raffinose, and bovine serum albumin (BSA) solutions. The results showed that: (1) freezing point depression and vapor pressure deficit share theoretically the same physicochemical basis; (2) theoretically, they are proportional to the molal concentration of the aqueous solutions to be measured; (3) in practice, the osmotic pressure levels of aqueous NaCl, KCl, CaCl(2), glucose, sucrose, and raffinose solutions increase in proportion to their molal concentrations and there is little inconsistency between those measured by freezing point depression and vapor pressure deficit; (4) the osmotic pressure levels of aqueous ethylene glycol and PEG solutions measured by freezing point depression differed from the values measured by vapor pressure deficit; (5) the osmotic pressure of aqueous BSA solution measured by freezing point depression differed slightly from that measured by vapor pressure deficit.

  10. Extractant compositions for co-extracting cesium and strontium, a method of separating cesium and strontium from an aqueous feed, and calixarene compounds

    DOEpatents

    Peterman,Dean R.; Meikrantz,David H.; Law,Jack D.; Riddle,Catherine L.; Todd,Terry A.; Greenhalgh,Mitchell R.; Tillotson,Richard D.; Bartsch,Richard A.; Moyer,Bruce A.; Delmau,Laetitia H.; Bonnesen,Peter V.

    2012-04-17

    A mixed extractant solvent that includes at least one dialkyloxycalix[4]arenebenzocrown-6 compound, 4',4',(5')-di-(t-butyldicyclohexano)-18-crown-6, at least one modifier, and, optionally, a diluent. The dialkyloxycalix[4]arenebenzocrown-6 compound is 1,3-alternate-25,27-di(octyloxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(decyloxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(dodecyloxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(2-ethylhexyl-1-oxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(3,7-dimethyloctyl-1-oxy)calix[4]arenebenzocrown-6, 1,3-alternate-25,27-di(4-butyloctyl-1-oxy)calix[4]arenebenzocrown-6, or combinations thereof. The modifier is a primary alcohol. A method of separating cesium and strontium from an aqueous feed is also disclosed, as are dialkyloxycalix[4]arenebenzocrown-6 compounds and an alcohol modifier.

  11. Photochemical effect of humic acid components separated using molecular imprinting method applying porphyrin-like substances as templates in aqueous solution.

    PubMed

    Yu, Chunyan; Zhang, Yaobin; Quan, Xie; Chen, Shuo; Han, Jianbo; Ou, Xiaoxia; Zhao, Jincai

    2010-08-01

    To elucidate the relationship between photochemical functions with the structure of humic acids (HA), we developed a molecular imprinting method to separate the substances with given structure and investigated their photochemical behavior in aqueous solution. The substances with porphyrin-like core structure, such as chlorophyll or heme, were employed as template substances for preparing molecular imprinting polymers (MIP). The polymers were used to separate the substances with porphyrin-like structure from HA. Photochemical experiments were conducted to evaluate effects of the separated HA fractions on the photodegradation of coexisting organic pollutant. The results showed that all fractions bound by MIP accelerated photochemical degradation of coexisting 2,4-dichlorophenoxyacetic acid (2,4-D) under simulated sunlight (lambda>290 nm) irradiation, indicating that HA with porphyrin-like structure possesses better photoactivity than ones without the structure. The photochemical degradation of 2,4-D was enhanced when Fe(III), the ubiquitous element in natural aquatic systems, was added owing to the formation of Fe(III) complex with the HA. Electron paramagnetic resonance (EPR) spectra indicated that OH* and 1O2 radicals were generated in the solutions of HA fractions bound by MIP under simulated sunlight irradiation, implying that 2,4-D degradation could be related to oxidation reactions caused by reactive oxygen species (ROS).

  12. Thermochromic properties of W-doped VO2 thin films deposited by aqueous sol-gel method for adaptive infrared stealth application

    NASA Astrophysics Data System (ADS)

    Liu, Dongqing; Cheng, Haifeng; Xing, Xin; Zhang, Chaoyang; Zheng, Wenwei

    2016-07-01

    The W doped VO2 thin films with various W contents were successfully deposited by aqueous sol-gel method followed by a post annealing process. The derived thin films were characterized by X-ray diffraction, Raman spectra, scanning electron microscopy and atomic force microscopy. Besides, the resistance-temperature relationship and infrared emissivity in the waveband 7.5-14 μm were analyzed, and the effects of W doping on the thermochromic properties of VO2 thin films were studied. The results show that W atoms enter the crystal lattice of VO2 and the transition temperature decreases gradually with increasing doping amount of W. The emissivity of VO2-W-4% thin films has dropped to 0.4 when its real temperature is above 30 °C. The thermal infrared images were also examined under different temperature by thermal imager. The results indicate that the temperature under which W doped VO2 thin films begin to have lower emissivity decreases gradually with increasing doping amount of W. W doped VO2 thin films can control its infrared radiation intensity actively at a lower temperature level of 30 °C, which has great application prospects in the adaptive infrared stealth technology.

  13. Synthesis of sub-10 nm VO2 nanoparticles films with plasma-treated glass slides by aqueous sol-gel method

    NASA Astrophysics Data System (ADS)

    Lan, Shi-Di; Cheng, Chih-Chia; Huang, Chi-Hsien; Chen, Jem-Kun

    2015-12-01

    This paper describes an aqueous sol-gel synthesis of thermochromic thin films consisted of vanadium dioxide nanoparticles (VNPs) on glass slides. The glass slides were treated by argon/oxygen plasma to generate dispersedly negative charge sites on the surface to attract VO2+ from a sol-gel solution. After heat treatment in a low-pressure carbon monoxide/carbon dioxide (CO/CO2) atmosphere, the VNPs could be generated in sub-10 nm of particle size on the surface. Various levels of doping were achieved by adding small quantities of a water-soluble tungsten compound to the sol; however, the particle size increased slightly with the tungsten doping levels. The change in electrical conductivity with temperature for VNP films were measured and compared to VO2 crystalline films. VNP films exhibited the lower transition temperature of the semiconductor to metal phase change; at a doping level of 4 wt% the transition temperature was measured at 32.2 ± 1.2 and 24.1 ± 1.2 °C for the VO2 and VNP films, respectively. The VNP films showed excellent visible transparency and a large change in transmittance at near-infrared (NIR) wavelengths before and after the metal-insulator phase transition (MIT). The current method is a landmark in the development of nanostructured material toward applications in energy-saving smart windows.

  14. Novel method for simultaneous aqueous in situ derivatization of THC and THC-COOH in human urine samples: validation and application to real samples.

    PubMed

    Chericoni, S; Battistini, I; Dugheri, S; Pacenti, M; Giusiani, M

    2011-05-01

    The present work describes the validation of a novel aqueous in situ derivatization procedure with trimethyloxonium tetrafluoroborate (TMO) as methylating agent for the simultaneous, quantitative analysis of Δ(9)-tetrahydrocannabinol (THC) and 11-nor-Δ(9)-tetrahydrocannabinol carboxylic acid (THC-COOH) in human urine. The derivatizing agent is directly added to the urine sample and the methyl-derivatives are then recovered by liquid-liquid extraction procedure. Gas chromatography-mass spectrometry was used to detect the derivatives in selected ion monitoring mode. The limits of detection were 0.7 ng/mL for THC and 0.5 ng/mL for THC-COOH, whereas the limits of quantification were 1.9 and 0.9 ng/mL, respectively. The method has been applied to 60 real samples both positive and negative to immunochemical screening test resulting to be very useful and reliable in routine analysis of THC-COOH in human urine for toxicological and forensic purposes.

  15. Annealing effects on the optical and morphological properties of ZnO nanorods on AZO substrate by using aqueous solution method at low temperature

    PubMed Central

    2014-01-01

    Vertically aligned ZnO nanorods (NRs) on aluminum-doped zinc oxide (AZO) substrates were fabricated by a single-step aqueous solution method at low temperature. In order to optimize optical quality, the effects of annealing on optical and structural properties were investigated by scanning electron microscopy, X-ray diffraction, photoluminescence (PL), and Raman spectroscopy. We found that the annealing temperature strongly affects both the near-band-edge (NBE) and visible (defect-related) emissions. The best characteristics have been obtained by employing annealing at 400°C in air for 2 h, bringing about a sharp and intense NBE emission. The defect-related recombinations were also suppressed effectively. However, the enhancement decreases with higher annealing temperature and prolonged annealing. PL study indicates that the NBE emission is dominated by radiative recombination associated with hydrogen donors. Thus, the enhancement of NBE is due to the activation of radiative recombinations associated with hydrogen donors. On the other hand, the reduction of visible emission is mainly attributed to the annihilation of OH groups. Our results provide insight to comprehend annealing effects and an effective way to improve optical properties of low-temperature-grown ZnO NRs for future facile device applications. PMID:25520589

  16. Three-phase compositional modeling of CO2 injection by higher-order finite element methods with CPA equation of state for aqueous phase

    NASA Astrophysics Data System (ADS)

    Moortgat, Joachim; Li, Zhidong; Firoozabadi, Abbas

    2012-12-01

    Most simulators for subsurface flow of water, gas, and oil phases use empirical correlations, such as Henry's law, for the CO2 composition in the aqueous phase, and equations of state (EOS) that do not represent the polar interactions between CO2and water. Widely used simulators are also based on lowest-order finite difference methods and suffer from numerical dispersion and grid sensitivity. They may not capture the viscous and gravitational fingering that can negatively affect hydrocarbon (HC) recovery, or aid carbon sequestration in aquifers. We present a three-phase compositional model based on higher-order finite element methods and incorporate rigorous and efficient three-phase-split computations for either three HC phases or water-oil-gas systems. For HC phases, we use the Peng-Robinson EOS. We allow solubility of CO2in water and adopt a new cubic-plus-association (CPA) EOS, which accounts for cross association between H2O and CO2 molecules, and association between H2O molecules. The CPA-EOS is highly accurate over a broad range of pressures and temperatures. The main novelty of this work is the formulation of a reservoir simulator with new EOS-based unique three-phase-split computations, which satisfy both the equalities of fugacities in all three phases and the global minimum of Gibbs free energy. We provide five examples that demonstrate twice the convergence rate of our method compared with a finite difference approach, and compare with experimental data and other simulators. The examples consider gravitational fingering during CO2sequestration in aquifers, viscous fingering in water-alternating-gas injection, and full compositional modeling of three HC phases.

  17. Aqueous cleaning design presentation

    NASA Technical Reports Server (NTRS)

    Maltby, Peter F.

    1995-01-01

    The phase-out of CFC's and other ozone depleting chemicals has prompted industries to re-evaluate their present methods of cleaning. It has become necessary to find effective substitutes for their processes as well as to meet the new cleaning challenges of improved levels of cleanliness and to satisfy concerns about environmental impact of any alternative selected. One of the most popular alternatives being selected is aqueous cleaning. This method offers an alternative for removal of flux, grease/oil, buffing compound, particulates and other soils while minimizing environmental impact. What I will show are methods that can be employed in an aqueous cleaning system that will make it environmentally friendly, relatively simple to maintain and capable of yielding an even higher quality of cleanliness than previously obtained. I will also explore several drying techniques available for these systems and other alternatives along with recent improvements made in this technology. When considering any type of cleaning system, a number of variables should be determined before selecting the basic configuration. Some of these variables are: (1) Soil or contaminants being removed from your parts; (2) The level of cleanliness required; (3) The environmental considerations of your area; (4) Maintenance requirements; and (5) Operating costs.

  18. Multiresidue analytical method for the simultaneous determination of 72 micropollutants in aqueous samples with ultra high performance liquid chromatography-high resolution mass spectrometry.

    PubMed

    Wode, Florian; Reilich, Christa; van Baar, Patricia; Dünnbier, Uwe; Jekel, Martin; Reemtsma, Thorsten

    2012-12-28

    A multiresidue method for the simultaneous quantification of 72 micropollutants in aqueous samples by ultra high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) is described. A variety of substance classes like industrial chemicals, analgesics, anticonvulsants, antihypertensives, psychoactive substances, flame retardants, neutral and acidic pesticides are comprised. A sample volume of 1 mL was enriched by online solid phase extraction (SPE), separated on a 2.6 μm core-shell column and detected with an Exactive™ high resolution mass spectrometer. Simultaneous determination of compounds with different ionization behavior was achieved by polarity switching. One complete run lasted 15 min. The method was validated in the matrices drinking water (DW), diluted surface water (dSW) and diluted waste water treatment plant effluent (dWW) by analyzing 10 replicates spiked at two concentration levels. Limits of quantification (LOQs) ranged between 0.01 and 0.06 μg/L in DW, 0.03 and 0.38 μg/L in dSW, 0.06 and 0.38 μg/L in dWW. The accuracies were between 77 and 117% in DW, 70 and 121% in dSW, 71 and 121% in dWW for both spike levels, respectively. Five compounds in dSW and one compound in dWW were affected by matrix effects, leading to accuracies outside the ranges stated above. The precision for level 2 was excellent with relative standard deviations (RSDs) between 2.2 and 6.5% in DW, 0.5 and 4.9% in dSW and between 1.2 and 6.6% in dWW. PMID:23182284

  19. Method of uranium reclamation from aqueous systems by reactive ion exchange. [US DOE patent application; anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands

    DOEpatents

    Maya, L.

    1981-11-05

    A reactive ion exchange method for separation and recovery of values of uranium, neptunium, plutonium, or americium from substantially neutral aqueous systems of said metals comprises contacting said system with an effective amount of a basic anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands to achieve nearly 100% sorption of said actinyl ion onto said resin and an aqueous system practically free of said actinyl ions. The method is operational over an extensive range of concentrations from about 10/sup -6/ M to 1.0 M actinyl ion and a pH range of about 4 to 7. The method has particulr application to treatment of waste streams from Purex-type nuclear fuel reprocessing facilities and hydrometallurgical processes involving U, Np, P, or Am.

  20. Source mechanisms of micro-earthquakes induced in a fluid injection experiment at the HDR site Soultz-sous-Forêts (Alsace) in 2003 and their temporal and spatial variations

    NASA Astrophysics Data System (ADS)

    Horálek, Josef; Jechumtálová, Zuzana; Dorbath, Louis; Šílený, Jan

    2010-06-01

    We have inverted the peak amplitudes of direct P waves of 45 micro-earthquakes with magnitudes between M = 1.4 and 2.9, which occurred during and after the 2003 massive fluid injection in the GPK3 borehole of the Soultz-sous-Forêts Hot Dry Rock facility. These events were recorded by a surface seismic network of 15 stations operated by the Ecole et Observatoire des Sciences de la Terre, University of Strasbourg. The unconstrained moment tensor (MT) expression of the mechanism was applied, allowing the description of a general system of dipoles, that is, both double-couple (DC) and non-DC sources, as tensile fractures. The mechanisms of all but one event are dominantly DCs with a few per cent additional components at the most. We have checked carefully the reliability of the MT retrieval in bootstrap trials eliminating some data, by simulating the mislocation of the hypocentre and by applying simplified velocity models of the area in constructing Green's functions. In some of the trials non-DC components amounting to several tens of per cent appear, but the F-test classifies them as insignificant. Even the only micro-earthquake with an exceptionally high non-DC mechanism cannot be classified unambiguously-the F-test assigns similar significance to the pure DC solution. The massive dominance of the DC indicates the shear-slip as the mechanism of the micro-earthquakes investigated. The mechanisms display large variability and are of normal dip-slip, oblique normal to strike-slip types. The T-axes are fairly stable, being concentrated subhorizontally roughly in the E-W direction. On the contrary, the P-axes are ill constrained varying in the N-S direction from nearly vertical to nearly horizontal, which points to heterogeneous stress in the Soultz injected volume. This is in agreement with the stress pattern from in situ measurements: the minimum stress axis is well constrained to E-W, whereas the maximum and intermediate stress values are close to one another

  1. Study of complexation process between 4'-nitrobenzo-15-crown-5 and yttrium(III) cation in binary mixed non-aqueous solvents using conductometric method

    NASA Astrophysics Data System (ADS)

    Habibi, N.; Rounaghi, G. H.; Mohajeri, M.

    2012-12-01

    The complexation reaction of macrocyclic ligand (4'-nitrobenzo-15C5) with Y3+ cation was studied in acetonitrile-methanol (AN-MeOH), acetonitrile-ethanol (AN-EtOH), acetonitrile-dimethylformamide (AN-DMF) and ethylacetate-methanol (EtOAc-MeOH) binary mixtures at different temperatures using conductometry method. The conductivity data show that in all solvent systems, the stoichiometry of the complex formed between 4'-nitrobenzo-15C5 and Y3+ cation is 1: 1 (ML). The stability order of (4'-nitrobenzo-15C5). Y3+ complex in pure non-aqueous solvents at 25°C was found to be: EtOAc > EtOH > AN ≈ DMF > MeOH, and in the case of most compositions of the binary mixed solvents at 25°C it was: AN≈MeOH ≈ AN-EtOH > AN-DMF > EtOAc-MeOH. But the results indicate that the sequence of the stability of the complex in the binary mixed solutions changes with temperature. A non-linear behavior was observed for changes of log K f of (4'-nitrobenzo-15C5 · Y3+) complex versus the composition of the binary mixed solvents, which was explained in terms of solvent-solvent interactions and also the hetero-selective solvation of the species involved in the complexation reaction. The values of thermodynamic parameters (Δ H {c/ℴ} and Δ S {c/ℴ}) for formation of the complex were obtained from temperature dependent of the stability constant using the van't Hoff plots. The results represent that in most cases, the complex is both enthalpy and entropy stabilized and the values and also the sign of thermodynamic parameters are influenced by the nature and composition of the mixed solvents.

  2. Degradation of flumequine in aqueous solution by persulfate activated with common methods and polyhydroquinone-coated magnetite/multi-walled carbon nanotubes catalysts.

    PubMed

    Feng, Mingbao; Qu, Ruijuan; Zhang, Xiaoling; Sun, Ping; Sui, Yunxia; Wang, Liansheng; Wang, Zunyao

    2015-11-15

    In recent years, flumequine (FLU) has been ubiquitously detected in surface waters and municipal wastewaters. In light of its potential negative impacts to aquatic species, growing concern has been arisen for the removal of this antibiotic from natural waters. In this study, the kinetics, degradation mechanisms and pathways of aqueous FLU by persulfate (PS) oxidation were systematically determined. Three common activation methods, including heat, Fe(2+) and Cu(2+), and a novel heterogeneous catalyst, namely, polyhydroquinone-coated magnetite/multi-walled carbon nanotubes (Fe3O4/MWCNTs/PHQ), were investigated to activate PS for FLU removal. It was found that these three common activators enhanced FLU degradation obviously, while several influencing factors, such as solution pH, inorganic ions (especially HCO3(-) at 5 mmol/L) and dissolved organic matter extracts, exerted their different effects on FLU removal. The catalysts were characterized, and an efficient catalytic degradation performance, high stability and excellent reusability were observed. The measured total organic carbon levels suggested that FLU can be effectively mineralized by using the catalysts. Radical mechanism was studied by combination of the quenching tests and electron paramagnetic resonance analysis. It was assumed that sulfate radicals predominated in the activation of PS with Fe3O4/MWCNTs/PHQ for FLU removal, while hydroxyl radicals also contributed to the catalytic oxidation process. In addition, a total of fifteen reaction intermediates of FLU were identified, from which two possible pathways were proposed involving hydroxylation, decarbonylation and ring opening. Overall, this study represented a systematical evaluation regarding the transformation process of FLU by PS, and showed that the heterogeneous catalysts can efficiently activate PS for FLU removal from the water environment.

  3. A new method of reconstituting the P-T conditions of fluid circulation in an accretionary prism (Shimanto, Japan) from microthermometry of methane-bearing aqueous inclusions

    NASA Astrophysics Data System (ADS)

    Raimbourg, Hugues; Thiéry, Régis; Vacelet, Maxime; Ramboz, Claire; Cluzel, Nicolas; Le Trong, Emmanuel; Yamaguchi, Asuka; Kimura, Gaku

    2014-01-01

    In paleo-accretionary prisms and the shallow metamorphic domains of orogens, circulating fluids trapped in inclusions are commonly composed of a mixture of salt water and methane, producing two types of fluid inclusions: methane-bearing aqueous and methane-rich gaseous fluid inclusions. In such geological settings, where multiple stages of deformation, veining and fluid influx are prevalent, textural relationships between aqueous and gaseous inclusions are often ambiguous, preventing the microthermometric determination of fluid trapping pressure and temperature conditions. To assess the P-T conditions of deep circulating fluids from the Hyuga unit of the Shimanto paleo-accretionary prism on Kyushu, Japan, we have developed a new computational code, applicable to the H2O-CH4-NaCl system, which allows the characterization of CH4-bearing aqueous inclusions using only the temperatures of their phase transitions estimated by microthermometry: Tmi, the melting temperature of ice; Thyd, the melting temperature of gas hydrate and Th,aq, homogenization temperature. This thermodynamic modeling calculates the bulk density and composition of aqueous inclusions, as well as their P-T isochoric paths in a P-T diagram with an estimated precision of approximatively 10%. We use this computational tool to reconstruct the entrapment P-T conditions of aqueous inclusions in the Hyuga unit, and we show that these aqueous inclusions cannot be cogenetic with methane gaseous inclusions present in the same rocks. As a result, we propose that pulses of a high-pressure, methane-rich fluid transiently percolated through a rock wetted by a lower-pressure aqueous fluid. By coupling microthermometric results with petrological data, we infer that the exhumation of the Hyuga unit from the peak metamorphic conditions was nearly isothermal and ended up under a very hot geothermal gradient. In subduction or collision zones, modeling aqueous fluid inclusions in the ternary H2O-CH4-NaCl system and not

  4. Evaluation of Seismic Methods for Inferring Fluid Migration in Volcanic Regions

    NASA Astrophysics Data System (ADS)

    Lucero, Jaron Joshua James

    The classic concepts of fluid transport derived for sedimentary environments are generally not applicable to the study of magmatic transport. High fluid viscosity and negligible rock permeability should preclude magma transport, yet dikes, sills, and other intrusive features are commonly observed. Relationships between intrusive units and regional paleo-stress fields are well described, but the dynamic interactions between igneous fluid and competent rock that ultimately produce magma intrusions are not. Elevated seismicity is often observed in conjunction with volcanic activity, and is generally thought to indicate magmatic intrusion. This study examined the unique information that seismic data can provide about magmatic processes as they occur. Specifically, methods for deriving transport volume from fluid induced seismicity were evaluated. An approach proposed by Herbert Shaw linked total scalar seismic moment release and source region volume distortion. This relationship was tested using data from various fluid injection experiments by comparing observed seismicity with injected fluid volume. A second method examined seismic events from an earthquake swarm near the Yellowstone caldera for evidence of tensile-crack source mechanisms, which couldindicate igneous intrusion. Similar investigations have been successfully conducted using larger magnitude events. The Yellowstone swarm events were too small for traditional approaches, but were appropriately sized to assess the suitability of a different inversion technique for characterizing smaller events. A technique for improving the quality of the seismic dataset is also discussed. After further development, the techniques described may provide additional constraints on rates of active magma transport in volcanic areas. The results obtained by this study were generally consistent with predictions of the McGarr-Shaw method, and have illuminated the additional considerations that must be addressed when testing the

  5. Highly Sensitive and Selective Method for Detecting Ultratrace Levels of Aqueous Uranyl Ions by Strongly Photoluminescent-Responsive Amine-Modified Cadmium Sulfide Quantum Dots.

    PubMed

    Dutta, R K; Kumar, Ambika

    2016-09-20

    Detection of ultratrace levels of aqueous uranyl ions without using sophisticated analytical instrumentation and a tedious sample preparation method is a challenge for environmental monitoring and mitigation. Here we present a novel yet simple analytical method for highly sensitive and specific detection of uranyl ions via photoluminescence quenching of CdS quantum dots. We have demonstrated a new approach for synthesizing highly water-soluble and strong photoluminescence-emitting CdS quantum dots (i.e., CdS-MAA and CdS-MAA-TU) of sizes less than 3 nm. The structural, morphological, and optical properties of both the batches of CdS quantum dots were thoroughly characterized by XRD, high-resolution transmission electron microscopy (HRTEM), zeta potential, UV-visible absorption, and photoluminescence spectroscopy. Compared to the batch of CdS quantum dots prepared by capping with only mercaptoacetic acid (CdS-MAA), the batch prepared by capping with mercaptoacetic acid and thiourea in tandem (CdS-MAA-TU) exhibited higher quantum yield= 16.64 ± 1.02%, and more importantly, CdS-MAA-TU exhibited significantly a higher order of photoluminescence quenching responses when treated with ultratrace concentrations of uranyl ions. Under the optimized conditions, the sensitivity of detecting uranyl ion by CdS-MAA-TU was several folds better (0.316 L/ μg) than that of CdS-MAA (0.0053 (L/μg/), as determined from their respective Stern-Volmer plots. Qualitatively, CdS-MAA-TU probe can be used for visual detection of uranyl ions of concentration greater than 5 μg/L. However, the instrumental method of analysis based on photoluminescence spectroscopy confirmed the feasibility for quantitative analysis of ultratrace concentrations of uranyl ions as implied from a very low limit of detection (LoD = 0.07 μg/L) and limit of quantification (LoQ = and 0.231 μg/L). Systematic studies revealed very high selectivity for uranyl ion detection, though minor interference from Cu(2+), Pb(2

  6. A method for dye extraction using an aqueous two-phase system: Effect of co-occurrence of contaminants in textile industry wastewater.

    PubMed

    Borges, Gabriella Alexandre; Silva, Luciana Pereira; Penido, Jussara Alves; de Lemos, Leandro Rodrigues; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias

    2016-12-01

    This paper reports a green and efficient procedure for extraction of the dyes Malachite Green (MG), Methylene Blue (MB), and Reactive Red 195 (RR) using an aqueous two-phase system (ATPS). An ATPS consists mainly of water, together with polymer and salt, and does not employ any organic solvent. The extraction efficiency was evaluated by means of the partition coefficients (K) and residual percentages (%R) of the dyes, under different experimental conditions, varying the tie-line length (TLL) of the system, the pH, the type of ATPS-forming electrolyte, and the type of ATPS-forming polymer. For MG, the best removal (K = 4.10 × 10(4), %R = 0.0069%) was obtained with the ATPS: PEO 1500 + Na2C4H4O6 (TLL = 50.21% (w/w), pH = 6.00). For MB, the maximum extraction (K = 559.9, %R = 0.258%) was achieved with the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 1.00). Finally for RR, the method that presented the best results (K = 3.75 × 10(4), %R = 0.237%) was the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 6.00). The method was applied to the recovery of these dyes from a textile effluent sample, resulting in values of K of 1.17 × 10(4), 724.1, and 3.98 × 10(4) for MG, MB, and RR, respectively, while the corresponding %R values were 0.0038, 0.154, and 0.023%, respectively. In addition, the ATPS methodology provided a high degree of color removal (96.5-97.95%) from the textile effluent. PMID:27591846

  7. A method for dye extraction using an aqueous two-phase system: Effect of co-occurrence of contaminants in textile industry wastewater.

    PubMed

    Borges, Gabriella Alexandre; Silva, Luciana Pereira; Penido, Jussara Alves; de Lemos, Leandro Rodrigues; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias

    2016-12-01

    This paper reports a green and efficient procedure for extraction of the dyes Malachite Green (MG), Methylene Blue (MB), and Reactive Red 195 (RR) using an aqueous two-phase system (ATPS). An ATPS consists mainly of water, together with polymer and salt, and does not employ any organic solvent. The extraction efficiency was evaluated by means of the partition coefficients (K) and residual percentages (%R) of the dyes, under different experimental conditions, varying the tie-line length (TLL) of the system, the pH, the type of ATPS-forming electrolyte, and the type of ATPS-forming polymer. For MG, the best removal (K = 4.10 × 10(4), %R = 0.0069%) was obtained with the ATPS: PEO 1500 + Na2C4H4O6 (TLL = 50.21% (w/w), pH = 6.00). For MB, the maximum extraction (K = 559.9, %R = 0.258%) was achieved with the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 1.00). Finally for RR, the method that presented the best results (K = 3.75 × 10(4), %R = 0.237%) was the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 6.00). The method was applied to the recovery of these dyes from a textile effluent sample, resulting in values of K of 1.17 × 10(4), 724.1, and 3.98 × 10(4) for MG, MB, and RR, respectively, while the corresponding %R values were 0.0038, 0.154, and 0.023%, respectively. In addition, the ATPS methodology provided a high degree of color removal (96.5-97.95%) from the textile effluent.

  8. Analytical applications of partitioning in aqueous two-phase systems: Exploring protein structural changes and protein-partner interactions in vitro and in vivo by solvent interaction analysis method.

    PubMed

    Zaslavsky, Boris Y; Uversky, Vladimir N; Chait, Arnon

    2016-05-01

    This review covers the fundamentals of protein partitioning in aqueous two-phase systems (ATPS). Included is a review of advancements in the analytical application of solute partitioning in ATPS over the last two decades, with multiple examples of experimental data providing evidence that phase-forming polymers do not interact with solutes partitioned in ATPS. The partitioning of solutes is governed by the differences in solute interactions with aqueous media in the two phases. Solvent properties of the aqueous media in these two phases may be characterized and manipulated. The solvent interaction analysis (SIA) method, based on the solute partitioning in ATPS, may be used for characterization and analysis of individual proteins and their interactions with different partners. The current state of clinical proteomics regarding the discovery and monitoring of new protein biomarkers is discussed, and it is argued that the protein expression level in a biological fluid may be not the optimal focus of clinical proteomic research. Multiple examples of application of the SIA method for discovery of changes in protein structure and protein-partner interactions in biological fluids are described. The SIA method reveals new opportunities for discovery and monitoring structure-based protein biomarkers.

  9. APPLICATION OF LASERS AND LASER-OPTICAL METHODS IN LIFE SCIENCES Low-frequency four-wave mixing spectroscopy of biomolecules in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Bunkin, Aleksei F.; Pershin, S. M.

    2011-01-01

    Four-wave mixing (FWM) spectroscopy is used to detect the rotational resonances of H2O and H2O2 molecules in DNA and denatured DNA aqueous solutions in the range ±10 cm-1 with a spectral resolution of 3 GHz. It is found that the resonance contribution of the rotational transitions of these molecules increases significantly in solutions rather than in distilled water. This fact is interpreted as a manifestation of specific properties of a hydration layer at DNA—water and denatured DNA—water interfaces. Analysis of the FWM spectra shows that the concentration of H2O2 molecules in the hydration layer of the DNA solution increases by a factor of 3 after denaturation. The FWM spectra of aqueous solutions of α-chymotrypsin protein are obtained in the range ±7cm-1 at the protein concentrations between 0 and 20 mg cm-3. It is found that the hypersound velocity in the protein aqueous solution, measured by the shift of Brillouin components in the scattering spectrum, obeys a cubic dependence on the protein concentration and reaches a value of about 3000 m s-1 at 20 mg cm-3.

  10. Germanium: An aqueous processing review

    SciTech Connect

    Lier, R.J.M. van; Dreisinger, D.B.

    1995-08-01

    In industrial aqueous solutions, germanium generally occurs in trace amounts amid high concentrations of other metals, such as zinc, copper and iron. Separation of germanium from these metals as well as its isolation from gallium and indium pose a real challenge to the hydrometallurgist. After a brief discussion of the aqueous chemistry of germanium, this paper reviews the flowsheet of the Apex Mine in Utah. The Apex property was the only mine in the world to be operated primarily for production of gallium and germanium, but apparently closed due to great operating difficulties. Several process variants proposed for the treatment of the Apex ore, including bioleaching methods, are addressed. Following a more general description of the behavior of germanium in hydrometallurgical zinc processing streams, available technology for its recovery from aqueous solutions is summarized. Precipitation, solvent extraction, ion exchange, electrowinning, ion flotation and liquid-membrane separation are all outlined in terms of the aqueous chemistry of germanium. Finally, the production of high purity germanium dioxide and metal is briefly discussed. 61 refs.

  11. Immobilized metal ion affinity partitioning, a method combining metal-protein interaction and partitioning of proteins in aqueous two-phase systems.

    PubMed

    Birkenmeier, G; Vijayalakshmi, M A; Stigbrand, T; Kopperschläger, G

    1991-02-22

    Immobilized metal ions were used for the affinity extraction of proteins in aqueous two-phase systems composed of polyethylene glycol (PEG) and dextran or PEG and salt. Soluble chelating polymers were prepared by covalent attachment of metal-chelating groups to PEG. The effect on the partitioning of proteins of such chelating PEG derivatives coordinated with different metal ions is demonstrated. The proteins studied were alpha 2-macroglobulin, tissue plasminogen activator, superoxide dismutase and monoclonal antibodies. The results indicate that immobilized metal ion affinity partitioning provides excellent potential for the extraction of proteins. PMID:1710621

  12. Effect of intrajejunal acidity on lipid digestion and aqueous solubilisation of bile acids and lipids in health, using a new simple method of lipase inactivation.

    PubMed Central

    Zentler-Munro, P L; Fine, D R; Fitzpatrick, W J; Northfield, T C

    1984-01-01

    We have investigated whether acid-mediated bile acid precipitation, pancreatic enzyme inactivation, and fatty acid partitioning occur in health when intraluminal pH falls below 5. In order to assess lipolysis and aqueous solubilisation of lipid, we first developed a new technique for inactivating lipase in jejunal aspirate (acid inactivation), and showed it to be more effective and simpler than the established technique (heat inactivation). We then studied 14 healthy subjects, aspirating jejunal content for three hours after a liquid meal, and pooling according to pH. Eighteen per cent of the total aspirate was collected at pH less than 5 compared with 56% at pH greater than 6 (p less than 0.01). Forty eight per cent of the bile acids were precipitated at pH less than 5 compared with 18% at pH greater than 6 (p less than 0.01), leading to a reduction in aqueous phase bile acid concentration at low pH (2.1 mmol/l at pH less than 5 vs 5.8 mmol/l at pH greater than 6, p less than 0.01). Lipase activity was reduced at low pH (133 IU/l at pH less than 5 vs 182 IU/l at pH greater than 6, p less than 0.01), leading to reduced lipolysis at low pH (14% at pH less than 5 vs 32% at pH greater than 6, p less than 0.01). Aqueous phase lipid concentration was reduced at low pH (3.5 mmol/l at pH less than 5 vs 12.5 mmol/l at pH greater than 6, p less than 0.01). This reduction was less dependent on bile acid precipitation than on lipase inactivation and fatty acid partitioning. We conclude that intraluminal acidity influences aqueous solubilisation of bile acids and lipid in health. PMID:6714793

  13. Continuous Aqueous Tritium Monitoring

    SciTech Connect

    Hofstetter, K.J.

    1995-03-29

    Continuous monitoring for tritium in the aqueous effluents of selected Savannah River Site (SRS) facilities is performed using a custom designed system that includes an automated water purification system and a flow-through radiation detection system optimized for tritium. Beads of plastic scintillators coupled with coincidence electronics provide adequate sensitivity (=25kBz/L) for tritium break-through detection int he aqueous discharge stream from these facilities. The tritium effluent water monitors (TEWMs) at SRS provide early warning (within 30 minutes) of an unanticipated release of tritium, supplement the routine sampling surveillances, and mitigate the impact of aqueous plant discharges of tritium releases to the environment.

  14. In situ study of mass transfer in aqueous solutions under high pressures via Raman spectroscopy: A new method for the determination of diffusion coefficients of methane in water near hydrate formation conditions

    USGS Publications Warehouse

    Lu, W.J.; Chou, I.-Ming; Burruss, R.C.; Yang, M.Z.

    2006-01-01

    A new method was developed for in situ study of the diffusive transfer of methane in aqueous solution under high pressures near hydrate formation conditions within an optical capillary cell. Time-dependent Raman spectra of the solution at several different spots along the one-dimensional diffusion path were collected and thus the varying composition profile of the solution was monitored. Diffusion coefficients were estimated by the least squares method based on the variations in methane concentration data in space and time in the cell. The measured diffusion coefficients of methane in water at the liquid (L)-vapor (V) stable region and L-V metastable region are close to previously reported values determined at lower pressure and similar temperature. This in situ monitoring method was demonstrated to be suitable for the study of mass transfer in aqueous solution under high pressure and at various temperature conditions and will be applied to the study of nucleation and dissolution kinetics of methane hydrate in a hydrate-water system where the interaction of methane and water would be more complicated than that presented here for the L-V metastable condition. ?? 2006 Society for Applied Spectroscopy.

  15. Effect of Rare Earth Oxide Content on Nanograined Base Metal Electrode Multilayer Ceramic Capacitor Powder Prepared by Aqueous Chemical Coating Method

    NASA Astrophysics Data System (ADS)

    Zhang, Yichi; Wang, Xiaohui; Kim, Jinyong; Li, Longtu

    2013-02-01

    The aqueous chemical coating route is highly effective in preparing BaTiO3 nanoparticles uniformly coated with additives. Such nanoparticles can be used to produce nano-grained temperature stable BaTiO3 ceramics with core-shell structure, fulfilling the need of next-generation ultrathin layer base metal electrode (BME) multilayer ceramic capacitors (MLCCs). Rare earth oxides are an important class of additives owing to their ability to fulfill both donor and acceptor roles. In this paper, the effects of Y2O3 and Ho2O3 co-dopant content on dielectric and microstructural properties were investigated. By applying chemical coating, BaTiO3-based high performance temperature stabilized ceramics with the average grain size of about 130 nm, which met the requirement of next generation BME MLCCs, were obtained.

  16. Method for the direct observation and quantification of survival of bacteria attached to negatively or positively charged surfaces in an aqueous medium.

    PubMed

    Asadishad, Bahareh; Ghoshal, Subhasis; Tufenkji, Nathalie

    2011-10-01

    The risk of groundwater contamination by microbial pathogens is linked to their survival in the subsurface. Although there is a large body of literature on the inactivation behavior of suspended (planktonic) microorganisms, little is known about the inactivation of bacteria when attached to sand grain surfaces in groundwater aquifers. The main goal of this study was to develop a fluorescence-based experimental technique for evaluating the extent of inactivation over time of bacteria adhered onto a surface in an aqueous environment. Key features of the developed technique are as follows: (i) attached cells do not need to be removed from the surface of interest for quantification, (ii) bacterial inactivation can be examined in real-time for prolonged time periods, and (iii) the system remains undisturbed (i.e., the aqueous environment is unchanged) during the assay. A negatively or positively charged substrate (i.e., bare or coated glass slide) was mounted in a parallel-plate flow cell, bacteria were allowed to attach onto the substrate, and the loss of bacterial membrane integrity and respiratory activity were investigated as a function of time by fluorescence microscopy using Live/Dead BacLight and BacLight RedoxSensor CTC (5-cyano-2,3-ditolyl tetrazolium chloride) viability assays. These two different measures of bacterial inactivation result in comparable trends in bacterial inactivation, confirming the validity of the experimental technique. The results of this work show that the developed technique is sensitive enough to distinguish between the inactivation kinetics of different representative bacteria attached to either a negatively charged (bare glass) surface or a positively charged (coated glass) surface. Hence, the technique can be used to characterize bacterial inactivation kinetics when attached to environmentally relevant surfaces over a broad range of groundwater chemistries.

  17. Reflectance of aqueous solutions

    NASA Technical Reports Server (NTRS)

    Querry, M. R.

    1972-01-01

    The optical properties and optical constants of water and aqueous solutions were studied to develop an accurate tabulation of graphical representations of the optical constants through a broad spectrum. Manuscripts of articles are presented concerning extinction coefficients, relative specular reflectance, and temperature effect on the water spectrum. Graphs of absolute reflectance, phase shifts, index of refraction, and extinction coefficients for water, heavy water and aqueous solutions are included.

  18. Mars Aqueous Processing System

    NASA Technical Reports Server (NTRS)

    Berggren, Mark; Wilson, Cherie; Carrera, Stacy; Rose, Heather; Muscatello, Anthony; Kilgore, James; Zubrin, Robert

    2012-01-01

    The goal of the Mars Aqueous Processing System (MAPS) is to establish a flexible process that generates multiple products that are useful for human habitation. Selectively extracting useful components into an aqueous solution, and then sequentially recovering individual constituents, can obtain a suite of refined or semi-refined products. Similarities in the bulk composition (although not necessarily of the mineralogy) of Martian and Lunar soils potentially make MAPS widely applicable. Similar process steps can be conducted on both Mars and Lunar soils while tailoring the reaction extents and recoveries to the specifics of each location. The MAPS closed-loop process selectively extracts, and then recovers, constituents from soils using acids and bases. The emphasis on Mars involves the production of useful materials such as iron, silica, alumina, magnesia, and concrete with recovery of oxygen as a byproduct. On the Moon, similar chemistry is applied with emphasis on oxygen production. This innovation has been demonstrated to produce high-grade materials, such as metallic iron, aluminum oxide, magnesium oxide, and calcium oxide, from lunar and Martian soil simulants. Most of the target products exhibited purities of 80 to 90 percent or more, allowing direct use for many potential applications. Up to one-fourth of the feed soil mass was converted to metal, metal oxide, and oxygen products. The soil residue contained elevated silica content, allowing for potential additional refining and extraction for recovery of materials needed for photovoltaic, semiconductor, and glass applications. A high-grade iron oxide concentrate derived from lunar soil simulant was used to produce a metallic iron component using a novel, combined hydrogen reduction/metal sintering technique. The part was subsequently machined and found to be structurally sound. The behavior of the lunar-simulant-derived iron product was very similar to that produced using the same methods on a Michigan iron

  19. Aqueous photolysis of niclosamide

    USGS Publications Warehouse

    Graebing, P.W.; Chib, J.S.; Hubert, T.D.; Gingerich, W.H.

    2004-01-01

    The photodegradation of [14C]niclosamide was studied in sterile, pH 5, 7, and 9 buffered aqueous solutions under artificial sunlight at 25.0 A? 1.0 A?C. Photolysis in pH 5 buffer is 4.3 times faster than in pH 9 buffer and 1.5 times faster than in pH 7 buffer. In the dark controls, niclosamide degraded only in the pH 5 buffer. After 360 h of continuous irradiation in pH 9 buffer, the chromatographic pattern of the degradates was the same regardless of which ring contained the radiolabel. An HPLC method was developed that confirmed these degradates to be carbon dioxide and two- and four-carbon aliphatic acids formed by cleavage of both aromatic rings. Carbon dioxide was the major degradate, comprising 40% of the initial radioactivity in the 360 h samples from both labels. The other degradates formed were oxalic acid, maleic acid, glyoxylic acid, and glyoxal. In addition, in the chloronitroaniline-labeled irradiated test solution, 2-chloro-4-nitroaniline was observed and identified after 48 h of irradiation but was not detected thereafter. No other aromatic compounds were isolated or observed in either labeled test system.

  20. Sucrose diffusion in aqueous solution.

    PubMed

    Price, Hannah C; Mattsson, Johan; Murray, Benjamin J

    2016-07-28

    The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes-Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle. PMID:27364512

  1. Sucrose diffusion in aqueous solution

    PubMed Central

    Murray, Benjamin J.

    2016-01-01

    The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes–Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle. PMID:27364512

  2. Rheology of aqueous foams

    NASA Astrophysics Data System (ADS)

    Dollet, Benjamin; Raufaste, Christophe

    2014-10-01

    Aqueous foams are suspensions of bubbles inside aqueous phases. Their multiphasic composition leads to a complex rheological behavior that is useful in numerous applications, from oil recovery to food/cosmetic processing. Their structure is very similar to the one of emulsions, so that both materials share common mechanical properties. In particular, the presence of surfactants at the gas-liquid interfaces leads to peculiar interfacial and dissipative properties. Foam rheology has been an active research topics and is already reported in several reviews, most of them covering rheometry measurements at the scale of the foam, coupled with interpretations at the local scale of bubbles or interfaces. In this review, we start following this approach, then we try to cover the multiscale features of aqueous foam flows, emphasizing regimes where intermediate length scales need to be taken into account or regimes fast enough regarding internal time scales so that the flow goes beyond the quasi-static limit. xml:lang="fr"

  3. Facile method for the synthesis of a magnetic CNTs-C@Fe-chitosan composite and its application in tetracycline removal from aqueous solutions.

    PubMed

    Ma, Jie; Zhuang, Yuan; Yu, Fei

    2015-06-28

    A magnetic CNTs-C@Fe-chitosan composite (CNTs-C@Fe-CS) was prepared based on as-prepared carbon nanotubes (APCNTs). The metal nanoparticles in APCNTs could be utilized directly without any purification treatment, and the carbon shells provide an effective barrier against oxidation, acid dissolution, and movement of the MNPs, thus ensuring the long-term stability of CNTs-C@Fe-CS. The results showed that CNTs-C@Fe-CS contained more abundant oxygen and nitrogen containing functional groups after chitosan modification and the composite had good magnetization characteristics, even in acidic solutions. Then CNTs-C@Fe-CS was used as an adsorbent for the removal of tetracycline from aqueous solutions. Adsorption experiments indicated that CNTs-C@Fe-CS have a good adsorption capacity (qe) of tetracycline (104 mg g(-1)). The Freundlich isotherm model fitted the experimental data better than the Langmuir isotherm model. Kinetic regression results showed that the adsorption kinetics was more accurately represented by a pseudo second-order model. Intra-particle diffusion was involved in the adsorption, but it was not the only rate-controlling step. Cu(2+) and humic acid could promote the adsorption of tetracycline on CNTs-C@Fe-CS. The CNTs-C@Fe-CS adsorbents could be effectively and quickly separated by applying an external magnetic field and the adsorption capacity was still maintained at 99.3 mg g(-1) after being used 10 times. Therefore, CNTs-C@Fe-CS is a promising magnetic nanomaterial for preconcentration and separation of organic pollutants for environmental remediation. PMID:26023730

  4. PROCESS FOR RECOVERING URANIUM FROM AQUEOUS PHOSPHORIC ACID LIQUORS

    DOEpatents

    Schmitt, J.M.

    1962-09-01

    A liquid-liquid extraction method is given for recovering uranium values from aqueous solutions. An acidic aqueous solution containing uranium values is contacted with an organic phase comprising an organic diluent and the reaction product of phosphorous pentoxide and a substantially pure dialkylphosphoric acid. The uranium values are transferred to the organic phase even from aqueous solutions containing a high concentration of strong uranium complexing agents such as phosphate ions. (AEC)

  5. Development of an automated on-line solid-phase extraction-high-performance liquid chromatographic method for the analysis of aniline, phenol, caffeine and various selected substituted aniline and phenol compounds in aqueous matrices.

    PubMed

    Patsias, J; Papadopoulou-Mourkidou, E

    2000-12-29

    A fully automated solid-phase extraction (SPE)-high-performance liquid chromatographic method has been developed for the simultaneous analysis of substituted anilines and phenols in aqueous matrices at the low- to sub-microg/l level. Diode array and electrochemical detection operated in tandem mode were used for analyte detection. Two new polymeric sorbent materials (Hysphere-GP and Hysphere-SH) were evaluated for the on-line SPE of substituted anilines and phenols from aqueous matrices and their performance was compared with the PRP-1 and PLRP-S sorbents. Hysphere-GP sorbent packed in 10 x 2 mm cartridges was found to give better results in terms of sensitivity and selectivity of the overall analytical method. The proposed analytical method was validated for the analysis of these compounds in Axios river water that receives industrial, communal and agricultural wastes. The detection limits for all the compounds range between 0.05 and 0.2 microg/l, except for aniline and phenol which have detection limits of 0.5 and 1 microg/l, respectively (aniline detected by electrochemical detection). The recoveries for all the compounds are higher than 75% except for aniline (6%), phenol (50%) and 3-chlorophenol (67%). Finally, in order to evaluate the efficiency of the Hysphere-GP (10 x 2 mm) cartridges for sample stabilization and storage, the stability of the compounds of interest at the sorbed state onto these cartridges has been evaluated under three different temperature regimes (deep freeze, refrigeration, 20 degrees C).

  6. Continuous aqueous tritium monitor

    DOEpatents

    McManus, Gary J.; Weesner, Forrest J.

    1989-05-30

    An apparatus for a selective on-line determination of aqueous tritium concentration is disclosed. A moist air stream of the liquid solution being analyzed is passed through a permeation dryer where the tritium and moisture and selectively removed to a purge air stream. The purge air stream is then analyzed for tritium concentration, humidity, and temperature, which allows computation of liquid tritium concentration.

  7. Changes to the Aqueous Humor Proteome during Glaucoma

    PubMed Central

    Kaeslin, Martha Andrea; Killer, Hanspeter Ezriel; Fuhrer, Cyril Adrian; Zeleny, Nauke; Huber, Andreas Robert; Neutzner, Albert

    2016-01-01

    Purpose To investigate the aqueous humor proteome in patients with glaucoma and a control group. Method Aqueous humor was obtained from five human donors diagnosed with primary open angle glaucoma (POAG) and five age- and sex-matched controls undergoing cataract surgery. Quantitative proteome analysis of the aqueous humor by hyper reaction monitoring mass spectrometry (HRM-MS) based on SWATH technology was performed. Results Expression levels of 87 proteins were found to be different between glaucomatous and control aqueous humor. Of the 87 proteins, 34 were significantly upregulated, whereas 53 proteins were downregulated in the aqueous humor from glaucoma patients compared to controls. Differentially expressed proteins were found to be involved in cholesterol-related, inflammatory, metabolic, antioxidant as well as proteolysis-related processes. Conclusion Glaucoma leads to profound changes to the aqueous humor proteome consistent with an altered metabolic state, an inflammatory response and impaired antioxidant defense. PMID:27788204

  8. FIA titrations of phenothiazine derivatives in aqueous micellar and non-aqueous media.

    PubMed

    Nemcová, Irena; Nesmerák, Karel; Rychlovský, Petr; Koutníková, Jitka

    2005-02-15

    New methods of flow injection analysis (FIA) neutralization titrations of phenothiazine derivatives in aqueous micellar medium of a cationic surfactant using potentiometric and spectrophotometric detection were proposed; titrations with a mixing gradient chamber and high-speed titrations were compared. The FIA titration method in non-aqueous media based on an official method of determination (titration with perchloric acid in anhydrous acetic acid) was also developed. Under optimized reaction conditions and flow-through parameters, the calibration range and equations, the sensitivity, and the repeatability of all methods were found and discussed. All titrations were assayed for medicinal forms.

  9. Enhanced Remedial Amendment Delivery to Subsurface Using Shear Thinning Fluid and Aqueous Foam

    SciTech Connect

    Zhong, Lirong; Szecsody, James E.; Oostrom, Martinus; Truex, Michael J.; Shen, Xin; Li, Xiqing

    2011-04-23

    A major issue with in situ subsurface remediation is the ability to achieve an even spatial distribution of remedial amendments to the contamination zones in an aquifer or vadose zone. Delivery of amendment to the aquifer using shear thinning fluid and to the vadose zone using aqueous foam has the potential to enhance the amendment distribution into desired locations and improve the remediation. 2-D saturated flow cell experiments were conducted to evaluate the enhanced sweeping, contaminant removal, and amendment persistence achieved by shear thinning fluid delivery. Bio-polymer xanthan gum solution was used as the shear thinning fluid. Unsaturated 1-D column and 2-D flow cell experiments were conducted to evaluate the mitigation of contaminant mobilization, amendment uniform distribution enhancement, and lateral delivery improvement by foam delivery. Surfactant sodium lauryl ether sulfate was used as the foaming agent. It was demonstrated that the shear thinning fluid injection enhanced the fluid sweeping over a heterogeneous system and increased the delivery of remedial amendment into low-permeability zones. The persistence of the amendment distributed into the low-perm zones by the shear thinning fluid was prolonged compared to that of amendment distributed by water injection. Foam delivery of amendment was shown to mitigate the mobilization of highly mobile contaminant from sediments under vadose zone conditions. Foam delivery also achieved more uniform amendment distribution in a heterogeneous unsaturated system, and demonstrated remarkable increasing in lateral distribution of the injected liquid compared to direct liquid injection.

  10. Enhanced remedial amendment delivery to subsurface using shear thinning fluid and aqueous foam.

    PubMed

    Zhong, Lirong; Szecsody, Jim; Oostrom, Mart; Truex, Mike; Shen, Xin; Li, Xiqing

    2011-07-15

    A major issue with in situ subsurface remediation is the ability to achieve an even spatial distribution of remedial amendments to the contamination zones in an aquifer or vadose zone. Amendment delivery to the aquifer using shear thinning fluid and to the vadose zone using aqueous foam has the potential to enhance the distribution. 2-D saturated flow cell experiments were conducted to evaluate the enhanced fluid sweeping over heterogeneous system, improved contaminant removal, and extended amendment presence in low-permeability zones achieved by shear thinning fluid delivery. Unsaturated column and flow cell experiments were conducted to investigate the improvement on contaminant mobilization mitigation, amendment distribution, and lateral delivery implemented by foam delivery. It was demonstrated that the shear thinning fluid injection enhanced the fluid sweeping and increased the delivery of remedial amendment into low-perm zones. The presence of amendment distributed by the shear thinning fluid in the low-permeability zones was increased. Foam delivery was shown to mitigate the mobilization of highly mobile contaminant from sediments. It also achieved more uniform amendment distribution in a heterogeneous unsaturated system, and demonstrated remarkable increasing in lateral distribution of the injected liquid compared to direct liquid injection.

  11. ANALYSIS OF VOLATILES AND SEMIVOLATILES BY DIRECT AQUEOUS INJECTION

    EPA Science Inventory

    Direct aqueous injection analysis (DAI) with gas chromatographic separation and ion trap mass spectral detection was used to analyze aqueous samples for g/L levels of 54 volatile and semivolatile compounds, and problematic non-purgeables and non-extractables. The method reduces ...

  12. Inverse hydrochemical models of aqueous extracts tests

    SciTech Connect

    Zheng, L.; Samper, J.; Montenegro, L.

    2008-10-10

    Aqueous extract test is a laboratory technique commonly used to measure the amount of soluble salts of a soil sample after adding a known mass of distilled water. Measured aqueous extract data have to be re-interpreted in order to infer porewater chemical composition of the sample because porewater chemistry changes significantly due to dilution and chemical reactions which take place during extraction. Here we present an inverse hydrochemical model to estimate porewater chemical composition from measured water content, aqueous extract, and mineralogical data. The model accounts for acid-base, redox, aqueous complexation, mineral dissolution/precipitation, gas dissolution/ex-solution, cation exchange and surface complexation reactions, of which are assumed to take place at local equilibrium. It has been solved with INVERSE-CORE{sup 2D} and been tested with bentonite samples taken from FEBEX (Full-scale Engineered Barrier EXperiment) in situ test. The inverse model reproduces most of the measured aqueous data except bicarbonate and provides an effective, flexible and comprehensive method to estimate porewater chemical composition of clays. Main uncertainties are related to kinetic calcite dissolution and variations in CO2(g) pressure.

  13. Mars aqueous chemistry experiment

    NASA Technical Reports Server (NTRS)

    Clark, Benton C.; Mason, Larry W.

    1993-01-01

    The Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. Progress for the first year MACE PIDDP is reported in two major areas of effort: (1) fluids handling concepts, definition, and breadboard fabrication and (2) aqueous chemistry ion sensing technology and test facility integration. A fluids handling breadboard was designed, fabricated, and tested at Mars ambient pressure. The breadboard allows fluid manipulation scenarios to be tested under the reduced pressure conditions expected in the Martian atmosphere in order to validate valve operations, orchestrate analysis sequences, investigate sealing integrity, and to demonstrate efficacy of the fluid handling concept. Additional fluid manipulation concepts have also been developed based on updated MESUR spacecraft definition. The Mars Aqueous Chemistry Experiment Ion Selective Electrode (ISE) facility was designed as a test bed to develop a multifunction interface for measurements of chemical ion concentrations in aqueous solution. The interface allows acquisition of real time data concerning the kinetics and heats of salt dissolution, and transient response to calibration and solubility events. An array of ion selective electrodes has been interfaced and preliminary calibration studies performed.

  14. Continuous aqueous tritium monitor

    DOEpatents

    McManus, G.J.; Weesner, F.J.

    1987-10-19

    An apparatus for a selective on-line determination of aqueous tritium concentration is disclosed. A moist air stream of the liquid solution being analyzed is passed through a permeation dryer where the tritium and moisture are selectively removed to a purge air stream. The purge air stream is then analyzed for tritium concentration, humidity, and temperature, which allows computation of liquid tritium concentration. 2 figs.

  15. An aqueous normal-phase chromatography coupled with tandem mass spectrometry method for determining unbound brain-to-plasma concentration ratio of AZD1775, a Wee1 kinase inhibitor, in patients with glioblastoma.

    PubMed

    Wu, Jianmei; Sanai, Nader; Bao, Xun; LoRusso, Patricia; Li, Jing

    2016-08-15

    A rapid, sensitive, and robust aqueous normal-phase chromatography method coupled with tandem mass spectrometry was developed and validated for the quantitation of AZD1775, a Wee-1 inhibitor, in human plasma and brain tumor tissue. Sample preparation involved simple protein precipitation with acetonitrile. Chromatographic separation was achieved on ethylene bridged hybrid stationary phases (i.e., Waters XBridge Amide column) under an isocratic elution with the mobile phase consisting of acetonitrile/ammonium formate in water (10mM, pH 3.0) (85:15,v/v) at a flow rate of 0.8mL/min for 5min. The lower limit of quantitation (LLOQ) was 0.2ng/mL of AZD1775 in plasma and tissue homogenate. The calibration curve was linear over AZD1775 concentration range of 0.2-1000ng/mL in plasma and tissue homogenate. The intra- and inter-day precision and accuracy were within the generally accepted criteria for bioanalytical method (<15%). The method was successfully applied to assess the penetration of AZD1775 across the blood-brain tumor barrier, as assessed by the unbound brain-to-plasma ratio, in patients with glioblastoma. PMID:27318641

  16. Determining trace amounts and the origin of formaldehyde impurity in Neisseria meningitidis A/C/Y/W-135-DT conjugate vaccine formulated in isotonic aqueous 1× PBS by improved C18-UPLC method.

    PubMed

    Gudlavalleti, Seshu K; Crawford, Erika N; Tran, Nhi N; Orten, Dana J; Harder, Jeffery D; Reddy, Jeeri R

    2015-03-25

    The ability to accurately measure and report trace amounts of residual formaldehyde impurity in a vaccine product is not only critical in the product release but also a regulatory requirement. In many bacterial or viral vaccine manufacturing procedures, formaldehyde is used either at a live culture inactivation step or at a protein de-toxification step or at both. Reported here is a validated and improved C18-UPLC method (developed based on previously published C-8 HPLC method) to determine the traces of formaldehyde process impurity in a liquid form Neisseria meningitidis A/C/Y/W-135-DT conjugate vaccine formulated in isotonic aqueous 1× PBS. UPLC C-18 column and the conditions described distinctly resolved the 2,4-DNPH-HCHO adduct from the un-reacted 2,4-DNPH as detected by TUV detector at 360 nm. This method was shown to be compatible with PBS formulation and extremely sensitive (with a quantitation limit of 0.05 ppm) and aided to determine formaldehyde contamination sources by evaluating the in-process materials as a track-down analysis. Final nanogram levels of formaldehyde in the formulated single dose vialed vaccine mainly originated from the diphtheria toxoid carrier protein used in the production of the conjugate vaccine, whereas relative contribution from polysaccharide API was minimal.

  17. Preparation and Properties of an Aqueous Ferrofluid

    NASA Astrophysics Data System (ADS)

    Enzel, Patricia; Adelman, Nicholas B.; Beckman, Katie J.; Campbell, Dean J.; Ellis, Arthur B.; Lisensky, George C.

    1999-07-01

    Ferrofluids are colloidal suspensions of surfactant-coated magnetic particles in a liquid medium. This paper describes a simple synthesis of an aqueous-based ferrofluid that may be used in an introductory science or engineering laboratory. Magnetite (Fe3O4) particles are precipitated by combining FeCl3 and FeCl2 in a 2:1 stoichiometric ratio in aqueous ammonia solution. The resulting particles, ~10-20 nm in diameter based on powder X-ray diffraction, are then treated with aqueous tetramethylammonium hydroxide, which acts as a surfactant. When the resulting ferrofluid is placed near a magnet, it forms conical spikes. This paper also describes a method for repelling both oil- and water-based ferrofluid from solid surfaces that would otherwise be stained by the fluid. Finally, a demonstration of the interaction between ferrofluid and magnetic fields, in which ferrofluid is induced to leap upward by a stack of magnets, is described.

  18. A NEW SW-846 METHOD FOR THE ANALYSIS OF TOXAPHENE AND TOXAPHENE CONGENERS IN SOLID AND AQUEOUS SAMPLES USING GAS CHROMATOGRAPHY / NEGATIVE ION MASS SPECTROMETRY

    EPA Science Inventory

    US EPA SW-846 methods have typically relied on dual column gas chromatography coupled with electron capture detection (GC-ECD) for analysis of low concentrations of organochlorine pesticides, including toxaphene, in environmental samples. Toxaphene is one of the most widely appl...

  19. Development of a filter-based method for detecting silver nanoparticles and their heteroaggregation in aqueous environments by surface-enhanced Raman spectroscopy.

    PubMed

    Guo, Huiyuan; Xing, Baoshan; He, Lili

    2016-04-01

    The rising application of silver nanoparticles (AgNPs) and subsequent release into aquatic systems have generated public concerns over their potential risk and harm to aquatic organisms and human health. Effective and practical analytical methods for AgNPs are urgently needed for their risk assessment. In this study we established an innovative approach to detect trace levels of AgNPs in environmental water through integrating a filtration technique into surface-enhanced Raman spectroscopy (SERS) and compared it with previously established centrifuge-based method. The purpose of filtration was to trap and enrich salt-aggregated AgNPs from water samples onto the filter membrane, through which indicator was then passed and complexed with AgNPs. The enhanced SERS signals of indicator could reflect the presence and quantity of AgNPs in the samples. The most favorable benefit of filtration is being able to process large volume samples, which is more practical for water samples, and greatly improves the sensitivity of AgNP detection. In this study, we tested 20 mL AgNPs-containing samples and the filter-based method is able to detect AgNPs as low as 5 μg/L, which is 20 folds lower than the centrifuge-based method. In addition, the speed and precision of the detection were greatly improved. This approach was used to detect trace levels of AgNPs in real environmental water successfully. Meanwhile, the heteroaggregation of AgNPs with minerals in water was reliably monitored by the new method. Overall, a combination of the filtration-SERS approach provides a rapid, simple, and sensitive way to detect AgNPs and analyze their environmental behavior. PMID:26774766

  20. Development and validation of an analytical method for the separation and determination of major bioactive curcuminoids in Curcuma longa rhizomes and herbal products using non-aqueous capillary electrophoresis.

    PubMed

    Anubala, S; Sekar, R; Nagaiah, K

    2014-06-01

    A simple, fast and efficient non-aqueous capillary electrophoresis method (NACE) was developed for the simultaneous determination of three major bioactive curcuminoids (CMNs) in Curcuma longa rhizomes and its herbal products. Good separation, resolution and reproducibility were achieved with the background electrolyte (BGE) consisting a mixture of 15.0 mM sodium tetraborate and 7.4 mM sodium hydroxide (NaOH) in 2:10:15 (v/v/v) of water, 1-propanol, and methanol. The influences of background electrolyte, sodium hydroxide, water, sodium dodecyl sulfate and hydroxylpropyl-β-cyclodextrin on separations were investigated. The separation was carried out in a fused-silica capillary tube with reverse polarity. Hydrodynamic injection of 25mbar for 12s was used for injecting samples and a voltage of 28 kV was applied for separation. The ultrasonication method was used for the extraction of CMNs from the turmeric herbal products and the extract was filtered and directly injected without any further treatments. The limits of detection and quantification were less than 5.0 and 14.6 µg/ml respectively for all CMNs. The percentage recoveries for CMNs were >97.2% (%RSD, <2.62). The results obtained by the method were compared with existing spectrophotometric and HPLC methods. The related compounds in the extract did not interfere in the determination of CMNs. The proposed NACE method is better than existing chromatographic and electrophoretic methods in terms of simple electrophoretic medium, fast analysis and good resolution.

  1. Use of electrical impedance spectroscopy as a practical method of investigating the formation of aggregates in aqueous solutions of dyes and surfactants.

    PubMed

    de Oliveira, Helinando P; de Melo, Celso P

    2011-06-01

    Molecular aggregation plays a key role in the physicochemical properties of dyes and surfactants. In this work, we show that electrical impedance spectroscopy (EIS) provides a practical method for the investigation of processes such as micellization in surfactants and dye dimerization. The electrical characterization of the structural phase transitions associated with aggregation events in these systems allows an accurate and direct determination of relevant parameters such as the corresponding critical concentrations for micelle formation and dimerization of these types of molecules, without the need of recurring to the use of auxiliary probe or reporter molecules. Because of its competitive advantages with respect to currently used methods (such as conductimetry and spectroscopic techniques), we argue that when implemented along the procedures described in this work, EIS becomes a simple and convenient technique for the characterization of aggregation processes in soft matter.

  2. Simple and sensitive electroanalytical method for the determination of ascorbic acid in urine samples using measurements in an aqueous cationic micellar medium.

    PubMed

    Dos Reis, Alaécio Pinheiro; Tarley, César Ricardo Teixeira; Mello, Lucilene Dornelles; Kubota, Lauro Tatsuo

    2008-12-01

    An electroanalytical study for the amperometric determination of ascorbic acid (AA) in a human urine sample at a bare glassy carbon electrode using the CPC (cetylpyridinium chloride) surfactant is described. Under the optimized conditions of E(pa), I(pa), CPC concentration and pH, the oxidation peak potential of the AA shifts towards a less positive potential, and the peak current increase in a significant way in the presence of the surfactant. Under the best conditions, the method provided a linear calibration curve to AA in a 0.1 mol L(-1) phosphate buffer solution (pH 7.0) in the concentration range from 5.0 x 10(-7) up to 4.3 x 10(-4) mol L(-1), with a detection limit of 2.0 x 10(-7) mol L(-1) and a high correlation coefficient (r = 0.9996). The recovery test presented values of 98 - 105%, suggesting a great potential of the proposed method for AA determination in complex samples, such as urine.

  3. Aqueous Humor Dynamics: A Review

    PubMed Central

    Goel, Manik; Picciani, Renata G; Lee, Richard K; Bhattacharya, Sanjoy K

    2010-01-01

    Glaucoma is a family of optic neuropathies which cause irreversible but potentially preventable vision loss. Vision loss in most forms of glaucoma is related to elevated IOP with subsequent injury to the optic nerve. Secretion of aqueous humor and regulation of its outflow are physiologically important processes for maintaining IOP in the normal range. Thus, understanding the complex mechanisms that regulate aqueous humor circulation is essential for management of glaucoma. The two main structures related to aqueous humor dynamics are the ciliary body and the trabecular meshwork (TM). Three mechanisms are involved in aqueous humor formation: diffusion, ultrafiltration and active secretion. Active secretion is the major contributor to aqueous humor formation. The aqueous humor flow in humans follows a circadian rhythm, being higher in the morning than at night. The aqueous humor leaves the eye by passive flow via two pathways - the trabecular meshwork and the uveoscleral pathway. In humans, 75% of the resistance to aqueous humor outflow is localized within the TM with the juxtacanalicular portion of the TM being the main site of outflow resistance. Glycosaminoglycan deposition in the TM extracellular matrix (ECM) has been suggested to be responsible for increased outflow resistance at this specific site whereas others have suggested deposition of proteins, such as cochlin, obstruct the aqueous humor outflow through the TM. The uveoscleral outflow pathway is relatively independent of the intraocular pressure and the proportion of aqueous humor exiting the eye via the uveoscleral pathway decreases with age. PMID:21293732

  4. High-throughput method of dioxin analysis in aqueous samples using consecutive solid phase extraction steps with the new C18 Ultraflow™ pressurized liquid extraction and automated clean-up.

    PubMed

    Youn, Yeu-Young; Park, Deok Hie; Lee, Yeon Hwa; Lim, Young Hee; Cho, Hye Sung

    2015-01-01

    A high-throughput analytical method has been developed for the determination of seventeen 2,3,7,8-substituted congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in aqueous samples. A recently introduced octadecyl (C18) disk for semi-automated solid-phase extraction of PCDD/Fs in water samples with a high level of particulate material has been tested for the analysis of dioxins. A new type of C18 disk specially designed for the analysis of hexane extractable material (HEM), but never previously reported for use in PCDD/Fs analysis. This kind of disk allows a higher filtration flow, and therefore the time of analysis is reduced. The solid-phase extraction technique is used to change samples from liquid to solid, and therefore pressurized liquid extraction (PLE) can be used in the pre-treatment. In order to achieve efficient purification, extracts from the PLE are purified using an automated Power-prep system with disposable silica, alumina, and carbon columns. Quantitative analyses of PCDD/Fs were performed by GC-HRMS using multi-ion detection (MID) mode. The method was successfully applied to the analysis of water samples from the wastewater treatment system of a vinyl chloride monomer plant. The entire procedure is in agreement with EPA1613 recommendations regarding the blank control, MDLs (method detection limits), accuracy, and precision. The high-throughput method not only meets the requirements of international standards, but also shortens the required analysis time from 2 weeks to 3d.

  5. [Determination of the overall migration of chemicals from the plastic packaging into the aqueous models of food using the EU methods].

    PubMed

    Cwiek-Ludwicka, Kazimiera; Stelmach, Agnieszka; Mazańska, Małgorzata; Jurkiewicz, Małgorzata; Półtorak, Hanna

    2004-01-01

    Overall migration from food plastic packaging to aquatic food simulants (distilled water, 3% acetic acid) was determined according to the EU methods. Testing conditions (time and temperature) reflected normal use of tested food packaging. The overall migration studies using different food simulants (distilled water, 3% acetic acid) shows that the migration rate was very low, far below the allowed limit (10 mg/dm2). The high results of overall migration into 3% acetic acid (average 250.2 mg/dm2), markedly exceeding the allowed limit, was found in the case of multilayer film. It means that the multilayer film tested does not comply with the migration limit and it can not be used as a food packaging for the sour foodstuffs of pH below 4.5. Differences between the magnitude of overall migration into distilled water (0.5-1.1 mg/dm2) and 3% acetic acid are probably due to the presence of easy washable substances into the sour medium. From that reason the application of such food packaging materials must be limited.

  6. Piezoelectric and opto-electrical properties of silver-doped ZnO nanorods synthesized by low temperature aqueous chemical method

    SciTech Connect

    Nour, E. S. Echresh, A.; Willander, M.; Nur, O.; Liu, Xianjie; Broitman, E.

    2015-07-15

    In this paper, we have synthesized Zn{sub 1−x}Ag{sub x}O (x = 0, 0.03, 0.06, and 0.09) nanorods (NRs) via the hydrothermal method at low temperature on silicon substrate. The characterization and comparison between the different Zn{sub 1−x}Ag{sub x}O samples, indicated that an increasing Ag concentration from x = 0 to a maximum of x = 0.09; All samples show a preferred orientation of (002) direction with no observable change of morphology. As the quantity of the Ag dopant was changed, the transmittances, as well as the optical band gap were decreased. X-ray photoelectron spectroscopy data clearly indicate the presence of Ag in ZnO crystal lattice. A nanoindentation-based technique was used to measure the effective piezo-response of different concentrations of Ag for both direct and converse effects. The value of the piezoelectric coefficient (d{sub 33}) as well as the piezo potential generated from the ZnO NRs and Zn{sub 1−x}Ag{sub x}O NRs was found to decrease with the increase of Ag fraction. The finding in this investigation reveals that Ag doped ZnO is not suitable for piezoelectric energy harvesting devices.

  7. Fluid injection device for high-pressure systems

    NASA Technical Reports Server (NTRS)

    Copeland, E. J.; Ward, J. B.

    1970-01-01

    Screw activated device, consisting of a compressor, shielded replaceable ampules, a multiple-element rubber gland, and a specially constructed fluid line fitting, injects measured amounts of fluids into a pressurized system. It is sturdy and easily manipulated.

  8. Microseismic techniques for avoiding induced seismicity during fluid injection

    DOE PAGES

    Matzel, Eric; White, Joshua; Templeton, Dennise; Pyle, Moira; Morency, Christina; Trainor-Guitton, Whitney

    2014-01-01

    The goal of this research is to develop a fundamentally better approach to geological site characterization and early hazard detection. We combine innovative techniques for analyzing microseismic data with a physics-based inversion model to forecast microseismic cloud evolution. The key challenge is that faults at risk of slipping are often too small to detect during the site characterization phase. Our objective is to devise fast-running methodologies that will allow field operators to respond quickly to changing subsurface conditions.

  9. Flow regimes for fluid injection into a confined porous medium

    SciTech Connect

    Zheng, Zhong; Guo, Bo; Christov, Ivan C.; Celia, Michael A.; Stone, Howard A.

    2015-02-24

    We report theoretical and numerical studies of the flow behaviour when a fluid is injected into a confined porous medium saturated with another fluid of different density and viscosity. For a two-dimensional configuration with point source injection, a nonlinear convection–diffusion equation is derived to describe the time evolution of the fluid–fluid interface. In the early time period, the fluid motion is mainly driven by the buoyancy force and the governing equation is reduced to a nonlinear diffusion equation with a well-known self-similar solution. In the late time period, the fluid flow is mainly driven by the injection, and the governing equation is approximated by a nonlinear hyperbolic equation that determines the global spreading rate; a shock solution is obtained when the injected fluid is more viscous than the displaced fluid, whereas a rarefaction wave solution is found when the injected fluid is less viscous. In the late time period, we also obtain analytical solutions including the diffusive term associated with the buoyancy effects (for an injected fluid with a viscosity higher than or equal to that of the displaced fluid), which provide the structure of the moving front. Numerical simulations of the convection–diffusion equation are performed; the various analytical solutions are verified as appropriate asymptotic limits, and the transition processes between the individual limits are demonstrated.

  10. Flow regimes for fluid injection into a confined porous medium

    DOE PAGES

    Zheng, Zhong; Guo, Bo; Christov, Ivan C.; Celia, Michael A.; Stone, Howard A.

    2015-02-24

    We report theoretical and numerical studies of the flow behaviour when a fluid is injected into a confined porous medium saturated with another fluid of different density and viscosity. For a two-dimensional configuration with point source injection, a nonlinear convection–diffusion equation is derived to describe the time evolution of the fluid–fluid interface. In the early time period, the fluid motion is mainly driven by the buoyancy force and the governing equation is reduced to a nonlinear diffusion equation with a well-known self-similar solution. In the late time period, the fluid flow is mainly driven by the injection, and the governingmore » equation is approximated by a nonlinear hyperbolic equation that determines the global spreading rate; a shock solution is obtained when the injected fluid is more viscous than the displaced fluid, whereas a rarefaction wave solution is found when the injected fluid is less viscous. In the late time period, we also obtain analytical solutions including the diffusive term associated with the buoyancy effects (for an injected fluid with a viscosity higher than or equal to that of the displaced fluid), which provide the structure of the moving front. Numerical simulations of the convection–diffusion equation are performed; the various analytical solutions are verified as appropriate asymptotic limits, and the transition processes between the individual limits are demonstrated.« less

  11. Fully Coupled Well Models for Fluid Injection and Production

    SciTech Connect

    White, Mark D.; Bacon, Diana H.; White, Signe K.; Zhang, Z. F.

    2013-08-05

    Wells are the primary engineered component of geologic sequestration systems with deep subsurface reservoirs. Wells provide a conduit for injecting greenhouse gases and producing reservoirs fluids, such as brines, natural gas, and crude oil, depending on the target reservoir. Well trajectories, well pressures, and fluid flow rates are parameters over which well engineers and operators have control during the geologic sequestration process. Current drilling practices provided well engineers flexibility in designing well trajectories and controlling screened intervals. Injection pressures and fluids can be used to purposely fracture the reservoir formation or to purposely prevent fracturing. Numerical simulation of geologic sequestration processes involves the solution of multifluid transport equations within heterogeneous geologic media. These equations that mathematically describe the flow of fluid through the reservoir formation are nonlinear in form, requiring linearization techniques to resolve. In actual geologic settings fluid exchange between a well and reservoir is a function of local pressure gradients, fluid saturations, and formation characteristics. In numerical simulators fluid exchange between a well and reservoir can be specified using a spectrum of approaches that vary from totally ignoring the reservoir conditions to fully considering reservoir conditions and well processes. Well models are a numerical simulation approach that account for local conditions and gradients in the exchange of fluids between the well and reservoir. As with the mathematical equations that describe fluid flow in the reservoir, variation in fluid properties with temperature and pressure yield nonlinearities in the mathematical equations that describe fluid flow within the well. To numerically simulate the fluid exchange between a well and reservoir the two systems of nonlinear multifluid flow equations must be resolved. The spectrum of numerical approaches for resolving these equations varies from zero coupling to full coupling. In this paper we describe a fully coupled solution approach for well model that allows for a flexible well trajectory and screened interval within a structured hexahedral computational grid. In this scheme the nonlinear well equations have been fully integrated into the Jacobian matrix for the reservoir conservation equations, minimizing the matrix bandwidth.

  12. Thermodynamic study of complex formation between Kryptofix-5 and Sn2+ in several individual and binary non-aqueous solvents using a conductometric method

    NASA Astrophysics Data System (ADS)

    Khoshnood, Razieh Sanavi; Hatami, Elaheh

    2014-12-01

    The complex formation between 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (Kryptofix-5) and Sn2+ ions was studied in pure acetonitrile (AN), dimethylformamide (DMF), 1,4-dioxane (DOX), and methanol (MeOH) and in acetonitrile-1,4-dioxane (AN-DOX), acetonitrile-dichloromethane (AN-DCM), acetonitrile-methanol (AN-MeOH), and acetonitrile-dimethylformamide (AN-DMF) binary mixed solvent solutions at different temperatures using conductometric method. 1: 1 [ML] complex is formed between the metal cation and ligand in most solvent systems but in the cases of AN-MeOH (MeOH = 90 mol %) binary mixture and in pure MeOH a 2: 1 [M2L] complex was observed, that is the stoichiometry of complexes may be changed by the nature of the medium. The stability order of the (Kryptofix-5·Sn)2+ complex in the studied binary mixed solvent solutions at 25°C was found to be AN-DOX > AN-DCM > AN-MeOH > AN-DMF and in the case of pure solvents at 25°C the sequence was the following: AN > DMF > DOX. A non-linear behavior was observed for changes of log K f of (Kryptofix-5·Sn)2+ complex versus the composition of the binary mixed solvents, which was explained in terms of solvent-solvent intractions and also by the preferential solvation of the f species involved in the complexation reaction. The values of standard enthalpy changes (Δ Hc°) for complexation reactions were obtained from the slope of the Van't Hoff plots and the changes in standard entropy (Δ Sc°) were calculated from the relationship Δ Gc,298.15° = Δ Hc° - 298.15Δ Sc°. The results show that in most cases, the (Kryptofix-5·Sn)2+ complex is both enthalpy and entropy stabilized.

  13. Pretreatment of Biomass by Aqueous Ammonia for Bioethanol Production

    NASA Astrophysics Data System (ADS)

    Kim, Tae Hyun; Gupta, Rajesh; Lee, Y. Y.

    The methods of pretreatment of lignocellulosic biomass using aqueous ammonia are described. The main effect of ammonia treatment of biomass is delignification without significantly affecting the carbohydrate contents. It is a very effective pretreatment method especially for substrates that have low lignin contents such as agricultural residues and herbaceous feedstock. The ammonia-based pretreatment is well suited for simultaneous saccharification and co-fermentation (SSCF) because the treated biomass retains cellulose as well as hemicellulose. It has been demonstrated that overall ethanol yield above 75% of the theoretical maximum on the basis of total carbohydrate is achievable from corn stover pretreated with aqueous ammonia by way of SSCF. There are two different types of pretreatment methods based on aqueous ammonia: (1) high severity, low contact time process (ammonia recycle percolation; ARP), (2) low severity, high treatment time process (soaking in aqueous ammonia; SAA). Both of these methods are described and discussed for their features and effectiveness.

  14. "Switchable water": aqueous solutions of switchable ionic strength.

    PubMed

    Mercer, Sean M; Jessop, Philip G

    2010-04-26

    "Salting out" is a standard method for separating water-soluble organic compounds from water. In this method, adding a large amount of salt to the aqueous solution forces the organic compound out of the aqueous phase. However, the method can not be considered sustainable because it creates highly salty water. A greener alternative would be a method that allows reversible salting out. Herein, we describe aqueous solutions of switchable ionic strength. Aqueous solutions of a diamine in water have essentially zero ionic strength but are converted by CO(2) into solutions of high ionic strength. The change is reversible. Application to the reversible salting out of THF from water is described. PMID:20186910

  15. Mars aqueous chemistry experiment

    NASA Technical Reports Server (NTRS)

    Clark, Benton C.; Mason, Larry W.

    1994-01-01

    Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles.

  16. Photocatalytic degradation of an azo textile dye (C.I. Reactive Red 195 (3BF)) in aqueous solution over copper cobaltite nanocomposite coated on glass by Doctor Blade method.

    PubMed

    Habibi, Mohammad Hossein; Rezvani, Zoya

    2015-08-01

    The degradation of C.I. Reactive Red 195 (3BF) in aqueous solution using copper cobaltite nanocomposite coated on glass by Doctor Blade method was studied. Structural, optical and morphological properties of nanocomposite coatings were characterized by X-ray powder diffractometry (XRD), diffuse reflectance spectroscopy (DRS) and field emission scanning electron microscopy (FESEM). The nanoparticles exhibit a particle size of 31 nm, showing a good nanoscale crystalline morphology. The photocatalytic activity of copper cobaltite nanocomposite coated on glass was studied by performing the photocatalytic degradation of 3BF at different irradiation time. The effect of irradiation time on the degradation of 3BF was studied and the results showed that more than 85% of the 3BF was degraded in 45 min of irradiation. The pseudo-first-order kinetic models were used and the rate constants were evaluated with pseudo first order rate constants of 4.10 × 10(-2) min(-1). The main advantage of the photocatalyst coated on glass overcomes the difficulties in separation and recycle of photocatalyst suspensions.

  17. Photocatalytic degradation of an azo textile dye (C.I. Reactive Red 195 (3BF)) in aqueous solution over copper cobaltite nanocomposite coated on glass by Doctor Blade method

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad Hossein; Rezvani, Zoya

    2015-08-01

    The degradation of C.I. Reactive Red 195 (3BF) in aqueous solution using copper cobaltite nanocomposite coated on glass by Doctor Blade method was studied. Structural, optical and morphological properties of nanocomposite coatings were characterized by X-ray powder diffractometry (XRD), diffuse reflectance spectroscopy (DRS) and field emission scanning electron microscopy (FESEM). The nanoparticles exhibit a particle size of 31 nm, showing a good nanoscale crystalline morphology. The photocatalytic activity of copper cobaltite nanocomposite coated on glass was studied by performing the photocatalytic degradation of 3BF at different irradiation time. The effect of irradiation time on the degradation of 3BF was studied and the results showed that more than 85% of the 3BF was degraded in 45 min of irradiation. The pseudo-first-order kinetic models were used and the rate constants were evaluated with pseudo first order rate constants of 4.10 × 10-2 min-1. The main advantage of the photocatalyst coated on glass overcomes the difficulties in separation and recycle of photocatalyst suspensions.

  18. Dechalcogenative Allylic Selenosulfide And Disulfide Rearrangements: Complementary Methods For The Formation Of Allylic Sulfides In The Absence Of Electrophiles. Scope, Limitations, And Application To The Functionalization Of Unprotected Peptides In Aqueous Media

    PubMed Central

    Crich, David; Krishnamurthy, Venkataramanan; Brebion, Franck; Karatholuvhu, Maheswaran; Subramanian, Venkataraman; Hutton, Thomas K.

    2008-01-01

    Primary allylic selenosulfates (seleno Bunte salts) and selenocyanates transfer the allylic selenide moiety to thiols giving primary allylic selenosulfides, which undergo rearrangement in the presence of PPh3 with the loss of selenium to give allylically rearranged allyl alkyl sulfides. This rearrangement may be conducted with prenyl-type selenosulfides to give isoprenyl alkyl sulfides. Alkyl secondary and tertiary allylic disulfides, formed by sulfide transfer from allylic heteroaryl disulfides to thiols, undergo desulfurative allylic rearrangement on treatment with PPh3 in methanolic acetonitrile at room temperature. With nerolidyl alkyl disulfides this rearrangement provides an electrophile-free method for the introduction of the farnesyl chain onto thiols. Both rearrangements are compatible with the full range of functionality found in the proteinogenic amino acids and it is demonstrated that the desulfurative rearrangement functions in aqueous media, enabling the derivatization of unprotected peptides. It is also demonstrated that the allylic disulfide rearrangement can be inducted in the absence of phosphine at room temperature by treatment with piperidine, or simply by refluxing in methanol. Under these latter conditions the reaction is also applicable to allyl aryl disulfides, providing allylically rearranged allyl aryl sulfides in good yields. PMID:17655306

  19. Development and application of a simultaneous SPE-method for polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, heterocyclic PAHs (NSO-HET) and phenols in aqueous samples from German Rivers and the North Sea.

    PubMed

    Siemers, Anne-Kathrin; Mänz, Jan Sebastian; Palm, Wolf-Ulrich; Ruck, Wolfgang K L

    2015-03-01

    Polycyclic aromatic hydrocarbons (PAHs), heterocyclic PAHs (NSO-HETs), alkylated PAHs and phenols are known as the prevailing contaminants in groundwater at tar contaminated sites. Besides these local sources, the concentrations and the distribution in particular of NSO-HETs in environmental samples, such as rivers, have received notably less attention. To investigate their occurrence in river basins two sensitive analytical methods for the simultaneous extraction of 86 substances including NSO-HETs, classical EPA-PAHs, alkylated PAHs and phenols were developed: liquid-liquid extraction for the whole water phase and solid phase extraction for the dissolved water phase only. Solely GC-MS or additionally LC-MSMS for fractionated basic nitrogen heterocycles (N-HETs) were used for quantification. Limits of quantification were in the low ngL(-1) range. Concentrations were determined in 29 aqueous samples from 8 relatively large rivers located in Lower Saxony (Germany) and the North Sea. NSO-HETs had comparable or even higher sum concentrations than EPA-PAHs. N-HETs, especially acridine and quinolines with concentrations of up to 20ngL(-1) per substance, were predominant.

  20. Simultaneous determination of 9-ethylphenanthrene, pyrene and 1-hydroxypyrene in an aqueous solution by synchronous fluorimetry using the double scans method and hydroxyl-propyl beta-cyclodextrin as a sensitizer.

    PubMed

    Zhang, Zhen-Xuan; Zhu, Ya-Xian; Zhang, Yong

    2015-11-01

    A novel method for the simultaneous determination of 9-ethylphenanthrene (9-EP), pyrene (Pyr) and 1-hydroxypyrene (1-OH-Pyr) in an aqueous solution using hydroxyl-propyl β-cyclodextrin (HPCD) as a sensitizer has been established. The overlap of the conventional fluorescence spectra of these molecules is resolved using synchronous fluorescence spectrometry with the double scans method. The simultaneous quantitative determination of three compounds was carried out with Δλ=36 nm and Δλ=55 nm. The signals detected at these three wavelengths (i.e., 298 nm, 337 nm and 351 nm) vary linearly when the concentrations of 9-EP, Pyr and 1-OH-Pyr were in the range of 5.00×10(-8)-1.60×10(-6) mol L(-1), 2.00×10(-8)-1.80×10(-6) mol L(-1), and 2.00×10(-8)-1.20×10(-5) mol L(-1), respectively. The limits of detection (LOD) for 9-EP, Pyr and 1-OH-Pyr were 3.97×10(-9) mol L(-1), 5.25×10(-)(9) mol L(-1), 4.20×10(-9) mol L(-1), respectively, with relative standard deviations (R.S.D.) of 1.62%, 2.45% and 1.73% (n=9), respectively. The inclusion behaviors between HPCD and the guest molecules were observed by synchronous fluorimetry and the association constants for the 1:1 complexes with HPCD were determined. The binding and complexation energies for different orientations are discussed. The proposed method was successfully applied to the analysis of 9-EP, Pyr and 1-OH-Pyr in tap and lake water with good recoveries in the range of 92.9-110.0%.

  1. Well aligned ZnO nanorods growth on the gold coated glass substrate by aqueous chemical growth method using seed layer of Fe3O4 and Co3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ibupoto, Z. H.; Khun, K.; Lu, Jun; Liu, Xianjie; AlSalhi, M. S.; Atif, M.; Ansari, Anees A.; Willander, M.

    2013-04-01

    In this study, Fe3O4 and Co3O4 nanoparticles were prepared by co-precipitation method and sol-gel method respectively. The synthesised nanoparticles were characterised by X-ray diffraction [XRD] and Raman spectroscopy techniques. The obtained results have shown the nanocrystalline phase of obtained Fe3O4 and Co3O4 nanoparticles. Furthermore, the Fe3O4 and Co3O4 nanoparticles were used as seed layer for the fabrication of well-aligned ZnO nanorods on the gold coated glass substrate by aqueous chemical growth method. Scanning electron microscopy (SEM), high resolution transmission electron microscopy [HRTEM], as well as XRD and energy dispersive X-ray techniques were used for the structural characterisation of synthesised ZnO nanorods. This study has explored highly dense, uniform, well-aligned growth pattern along 0001 direction and good crystal quality of the prepared ZnO nanorods. ZnO nanorods are only composed of Zn and O atoms. Moreover, X-ray photoelectron spectroscopy was used for the chemical analysis of fabricated ZnO nanorods. In addition, the structural characterisation and the chemical composition study and the optical investigation were carried out for the fabricated ZnO nanorods and the photoluminescence [PL] spectrum have shown strong ultraviolet (UV) peak at 381 nm for Fe3O4 nanoparticles seeded ZnO nanorods and the PL spectrum for ZnO nanorods grown with the seed layer of Co3O4 nanoparticles has shown a UV peak at 382 nm. The green emission and orange/red peaks were also observed for ZnO nanorods grown with both the seed layers. This study has indicated the fabrication of well aligned ZnO nanorods using the one inorganic nanomaterial on other inorganic nanomaterial due to their similar chemistry.

  2. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  3. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  4. Simultaneous Separation of Manganese, Cobalt, and Nickel by the Organic-Aqueous-Aqueous Three-Phase Solvent Extraction

    NASA Astrophysics Data System (ADS)

    Shirayama, Sakae; Uda, Tetsuya

    2016-04-01

    This research outlines an organic-aqueous-aqueous three-phase solvent extraction method and proposes its use in a new metal separation process for the recycling of manganese (Mn), cobalt (Co), and nickel (Ni) from used lithium ion batteries (LIBs). The three-phase system was formed by mixing xylene organic solution, 50 pct polyethylene glycol (PEG) aqueous solution, and 1 mol L-1 sodium sulfate (Na2SO4) aqueous solution. The xylene organic solution contained 2-ethylhexylphosphonic acid (D2EHPA) as an extractant for Mn ion, and the Na2SO4 aqueous solution contained 1 mol L-1 potassium thiocyanate (KSCN) as an extractant for Co ion. Concentrations of the metal ions were varied by dissolving metal sulfates in the Na2SO4 aqueous solution. As a result of the experiments, Mn, Co, and Ni ions were distributed in the xylene organic phase, PEG-rich aqueous phase, and Na2SO4-rich aqueous phase, respectively. The separation was effective when the pH value was around 4. Numerical simulation was also conducted in order to predict the distribution of metal ions after the multi-stage counter-current extractions.

  5. Catalyst and method for aqueous phase reactions

    DOEpatents

    Elliott, Douglas C.; Hart, Todd R.

    1999-01-01

    The present invention is a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional metal deposited onto the support in a second dispersed phase. The additional metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase without substantially affecting the catalytic activity, thereby increasing the life time of the catalyst.

  6. Method of recovering uranium from aqueous solution

    SciTech Connect

    Albright, R.L.

    1980-01-22

    Anion exchange resin derived from insoluble crosslinked polymers of vinyl benzyl chloride which are prepared by polymerizing vinyl benzyl chloride and a crosslinking monomer are particularly suitable in the treatment of uranium bearing leach liquors.

  7. Thermal Stability of Aqueous Polyurethanes Depending on the Applied Catalysts

    PubMed Central

    Cakic, Suzana; Nikolic, Goran; Lacnjevac, Caslav; Gligoric, Miladin; Stamenkovic, Jakov; Rajkovic, Milos B.; Barac, Miroljub

    2006-01-01

    The thermal stability of aqueous polyurethanes has been measured applying the thermogravimetric analysis. The aqueous polyurethanes (aqPUR) with catalysts of different selectivity have been studied by use of the dynamic method. To obtain degradations of 0.025, 0.05, and 0.10, employing the dynamic method, the heating rates of 0.5, 1, 2, 5, and 10 °C min-1 have been used in the range of 30-500 °C. Using the more selective catalysts in the aqueous polyurethanes, the total resulting time of the decompositon has been on the increase at all degrees of the degradation and at the particular starting temperature. This paper shows that the dynamic method based on the thermogravimetric analysis can be used to assess the thermal stability of the aqueous polyurethanes using the catalysts of different selectivity.

  8. Modeling aqueous solubility.

    PubMed

    Butina, Darko; Gola, Joelle M R

    2003-01-01

    This paper describes the development of an aqueous solubility model based on solubility data from the Syracuse database, calculated octanol-water partition coefficient, and 51 2D molecular descriptors. Two different statistical packages, SIMCA and Cubist, were used and the results were compared. The Cubist model, which comprises a collection of rules, each of which has an associated Multiple Linear Regression model (MLR), gave better overall results on a test set of 640 compounds with an overall squared correlation coefficient of 0.74 and an absolute average error of 0.68 log units. Both training and independent test sets had similar distributions of structures in terms of the different functionalities present-60% neutral, 14% acidic, 8% phenolic, 11% monobasic, 4% polybasic, and 3% zwitterionic molecules. Sets were designed by random selection, with 2688 (81%) and 640 (19%) molecules, respectively, forming the training and the test sets.

  9. In vitro porcine blood-brain barrier model for permeability studies: pCEL-X software pKa(FLUX) method for aqueous boundary layer correction and detailed data analysis.

    PubMed

    Yusof, Siti R; Avdeef, Alex; Abbott, N Joan

    2014-12-18

    In vitro blood-brain barrier (BBB) models from primary brain endothelial cells can closely resemble the in vivo BBB, offering valuable models to assay BBB functions and to screen potential central nervous system drugs. We have recently developed an in vitro BBB model using primary porcine brain endothelial cells. The model shows expression of tight junction proteins and high transendothelial electrical resistance, evidence for a restrictive paracellular pathway. Validation studies using small drug-like compounds demonstrated functional uptake and efflux transporters, showing the suitability of the model to assay drug permeability. However, one limitation of in vitro model permeability measurement is the presence of the aqueous boundary layer (ABL) resulting from inefficient stirring during the permeability assay. The ABL can be a rate-limiting step in permeation, particularly for lipophilic compounds, causing underestimation of the permeability. If the ABL effect is ignored, the permeability measured in vitro will not reflect the permeability in vivo. To address the issue, we explored the combination of in vitro permeability measurement using our porcine model with the pKa(FLUX) method in pCEL-X software to correct for the ABL effect and allow a detailed analysis of in vitro (transendothelial) permeability data, Papp. Published Papp using porcine models generated by our group and other groups are also analyzed. From the Papp, intrinsic transcellular permeability (P0) is derived by simultaneous refinement using a weighted nonlinear regression, taking into account permeability through the ABL, paracellular permeability and filter restrictions on permeation. The in vitro P0 derived for 22 compounds (35 measurements) showed good correlation with P0 derived from in situ brain perfusion data (r(2)=0.61). The analysis also gave evidence for carrier-mediated uptake of naloxone, propranolol and vinblastine. The combination of the in vitro porcine model and the software

  10. Removal of uranium from aqueous HF solutions

    DOEpatents

    Pulley, Howard; Seltzer, Steven F.

    1980-01-01

    This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a selected range and is employed in an amount providing a calcium fluoride/uranium weight ratio in a selected range. As applied to dilute HF solutions containing 120 ppm uranium, the method removes at least 92% of the uranium, without introducing contaminants to the product solution.

  11. Solvent and process for recovery of hydroxide from aqueous mixtures

    DOEpatents

    Moyer, Bruce A.; Chambliss, C. Kevin; Bonnesen, Peter V.; Keever, Tamara J.

    2001-01-01

    Hydroxide values and associated alkali metal may be recovered from alkaline aqueous solutions using classes of fluorinated alcohols in a water immiscible solvent. The alcohols are characterized by fluorine substituents which are proximal to the acidic alcohol protons and are located to adjust the acidity of the extractant and the solubility of the extractant in the solvent. A method for stripping the extractant and solvent to regenerate the extractant and purified aqueous hydroxide solution is described.

  12. Bismuth catalysts in aqueous media.

    PubMed

    Kobayashi, Shū; Ueno, Masaharu; Kitanosono, Taku

    2012-01-01

    Several bismuth-catalyzed synthetic reactions, which proceed well in aqueous media, are discussed. Due to increasing demand of water as a solvent in organic synthesis, catalysts that can be used in aqueous media are becoming more and more important. Although bismuth Lewis acids are not very stable in water, it has been revealed that they can be stabilized by basic ligands. Chiral amine and related basic ligands combined with bismuth Lewis acids are particularly useful in asymmetric catalysis in aqueous media. On the other hand, bismuth hydroxide is stable and works as an efficient catalyst for carbon-carbon bond-forming reactions in water. PMID:21769719

  13. Aqueous chlorination of resorcinol

    USGS Publications Warehouse

    Heasley, V.L.; Burns, M.D.; Kemalyan, N.A.; Mckee, T.C.; Schroeter, H.; Teegarden, B.R.; Whitney, S.E.; Wershaw, R. L.

    1989-01-01

    An investigation of the aqueous chlorination (NaOCl) of resorcinol is reported. The following intermediates were detected in moderate to high yield at different pH values and varying percentages of chlorination: 2-chloro-, 4-chloro-, 2,4-dichloro-, 4,6-dichloro- and 2,4,6-trichlororesorcinol. Only trace amounts of the intermediates were detected when the chlorination was conducted in the presence of phosphate buffer. This result has significant implications since resorcinol in phosphate buffer has been used as a model compound in several recent studies on the formation of chlorinated hydrocarbons during chlorination of drinking water. Relative rates of chlorination were determined for resorcinol and several of the chlorinated resorcinols. Resorcinol was found to chlorinate only three times faster than 2,4,6-trichlororesorcinol. The structure 2,4,6-trichlororesorcinol was established as a monohydrate even after sublimation. A tetrachloro or pentachloro intermediate was not detected, suggesting that the ring-opening step of such an intermediate must be rapid. ?? 1989.

  14. Mechanical Agitation For Aqueous Cleaning

    NASA Technical Reports Server (NTRS)

    Morgan, Gene E.; Hosking, Timothy J.

    1995-01-01

    Cleaning basket placed in aqueous cleaning solution mechanically agitated by air spring. Compressed air at oscillating pressure supplied to air spring to produce repeated vertical motion of cleaning basket.

  15. Ultrasound-assisted phase-transfer catalysis method in an aqueous medium to promote the Knoevenagel reaction: advantages over the conventional and microwave-assisted solvent-free/catalyst-free method.

    PubMed

    De-la-Torre, Pedro; Osorio, Edison; Alzate-Morales, Jans H; Caballero, Julio; Trilleras, Jorge; Astudillo-Saavedra, Luis; Brito, Iván; Cárdenas, Alejandro; Quiroga, Jairo; Gutiérrez, Margarita

    2014-09-01

    Given the broad spectrum of uses of acrylonitrile derivatives as fluorescent probes, AChE inhibitors, and others, it is necessary to find easy, efficient and simple methods to synthesize and diversify these compounds. We report the results of a comparative study of the effects of three techniques on the reactions between heterocyclic aldehydes and 2-(benzo[d]thiazol-2-yl)acetonitrile: stirring; ultrasound coupled to PTC conditions (US-PTC); and MW irradiation (MWI) under solvent and catalyst-free conditions. The effects of conditions on reaction parameters were evaluated and compared in terms of reaction time, yield, purity and outcomes. The US-PTC method is more efficient than the MWI and conventional methods. The reaction times were considerably shorter, with high yields (>90%) and good levels of purity. In addition, X-ray diffraction analysis and quantum mechanical calculations, at the level of density functional theory (DFT), ratify obtaining acrylonitrile isomers with E configurations. The crystal structure of 3c is stabilized by weak C-Ho⋯N intermolecular interactions (Ho⋯NC=2.45 Å, Co⋯NC=3.348(3) Å, Ho⋯NC=162°), forming centrosymmetric ring R2(2) (20) along the crystallographic a axis. PMID:24650611

  16. Photochemistry of aqueous pyruvic acid.

    PubMed

    Griffith, Elizabeth C; Carpenter, Barry K; Shoemaker, Richard K; Vaida, Veronica

    2013-07-16

    The study of organic chemistry in atmospheric aerosols and cloud formation is of interest in predictions of air quality and climate change. It is now known that aqueous phase chemistry is important in the formation of secondary organic aerosols. Here, the photoreactivity of pyruvic acid (PA; CH3COCOOH) is investigated in aqueous environments characteristic of atmospheric aerosols. PA is currently used as a proxy for α-dicarbonyls in atmospheric models and is abundant in both the gas phase and the aqueous phase (atmospheric aerosols, fog, and clouds) in the atmosphere. The photoreactivity of PA in these phases, however, is very different, thus prompting the need for a mechanistic understanding of its reactivity in different environments. Although the decarboxylation of aqueous phase PA through UV excitation has been studied for many years, its mechanism and products remain controversial. In this work, photolysis of aqueous PA is shown to produce acetoin (CH3CHOHCOCH3), lactic acid (CH3CHOHCOOH), acetic acid (CH3COOH), and oligomers, illustrating the progression from a three-carbon molecule to four-carbon and even six-carbon molecules through direct photolysis. These products are detected using vibrational and electronic spectroscopy, NMR, and MS, and a reaction mechanism is presented accounting for all products detected. The relevance of sunlight-initiated PA chemistry in aqueous environments is then discussed in the context of processes occurring on atmospheric aerosols.

  17. All-aqueous multiphase microfluidics

    PubMed Central

    Song, Yang; Sauret, Alban; Cheung Shum, Ho

    2013-01-01

    Immiscible aqueous phases, formed by dissolving incompatible solutes in water, have been used in green chemical synthesis, molecular extraction and mimicking of cellular cytoplasm. Recently, a microfluidic approach has been introduced to generate all-aqueous emulsions and jets based on these immiscible aqueous phases; due to their biocompatibility, these all-aqueous structures have shown great promises as templates for fabricating biomaterials. The physico-chemical nature of interfaces between two immiscible aqueous phases leads to unique interfacial properties, such as an ultra-low interfacial tension. Strategies to manipulate components and direct their assembly at these interfaces needs to be explored. In this paper, we review progress on the topic over the past few years, with a focus on the fabrication and stabilization of all-aqueous structures in a multiphase microfluidic platform. We also discuss future efforts needed from the perspectives of fluidic physics, materials engineering, and biology for fulfilling potential applications ranging from materials fabrication to biomedical engineering. PMID:24454609

  18. Non-aqueous cleaning solvent substitution

    NASA Technical Reports Server (NTRS)

    Meier, Gerald J.

    1994-01-01

    A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of AlliedSignal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, was selected as the solvent of choice, and it was found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally-safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

  19. Non-aqueous cleaning solvent substitution

    SciTech Connect

    Meier, G.J.

    1994-01-01

    A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of Allied Signal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, has been selected as the solvent of choice, and has been found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

  20. Homogeneous ice freezing temperatures and ice nucleation rates of aqueous ammonium sulfate and aqueous levoglucosan particles for relevant atmospheric conditions.

    PubMed

    Knopf, Daniel Alexander; Lopez, Miguel David

    2009-09-28

    Homogeneous ice nucleation from micrometre-sized aqueous (NH4)2SO4 and aqueous levoglucosan particles is studied employing the optical microscope technique. A new experimental method is introduced that allows us to control the initial water activity of the aqueous droplets. Homogeneous ice freezing temperatures and ice melting temperatures of these aqueous solution droplets, 10 to 80 microm in diameter, are determined. Homogeneous ice nucleation from aqueous (NH4)2SO4 particles 5-39 wt% in concentration and aqueous levoglucosan particles with initial water activities of 0.85-0.99 yield upper limits of the homogeneous ice nucleation rate coefficients of up to 1x10(10) cm(-3) s(-1). The experimentally derived homogeneous ice freezing temperatures and upper limits of the homogeneous ice nucleation rate coefficients are compared with corresponding predictions of the water-activity-based ice nucleation theory [T. Koop, B. P. Luo, A. Tsias and T. Peter, Nature, 2000, 406, 611]. It is found that the water-activity-based ice nucleation theory can capture the experimentally derived ice freezing temperatures and homogeneous ice nucleation rate coefficients of the aqueous (NH4)2SO4 and aqueous levoglucosan particles. However, the level of agreement between experimentally derived and predicted values, in particular for homogeneous ice nucleation rate coefficients, crucially depends on the extrapolation method to obtain water activities at corresponding freezing temperatures. It is suggested that the combination of experimentally derived ice freezing temperatures and homogeneous ice nucleation rate coefficients can serve as a better validation of the water-activity-based ice nucleation theory than when compared to the observation of homogeneous ice freezing temperatures alone. The atmospheric implications with regard to the application of the water-activity-based ice nucleation theory and derivation of maximum ice particle production rates are briefly discussed.

  1. Monitoring of Aqueous Fullerene Dispersions by Thermal-Lens Spectrometry

    NASA Astrophysics Data System (ADS)

    Mikheev, I. V.; Volkov, D. S.; Proskurnin, M. A.; Korobov, M. V.

    2015-06-01

    Aqueous fullerene solutions (dispersions) are very promising materials of biomedicine and biotechnology. Of importance are the traceability of their production and characterization of their optical and colloidal properties. Thermal-lens spectrometry, as a method suitable for both optical and thermophysical studies, was used to elucidate the forms of non-modified fullerenes in their aqueous dispersions and to determine low concentrations of and fullerenes. It was shown that the residual amounts of toluene in aqueous fullerene dispersions made according to the solvent-exchange protocol could be detected by thermal lensing. As a result, the technique for the production of aqueous fullerene dispersions was improved compared to the existing data providing higher fullerene concentrations. The limits of detection of and fullerenes are approximately , which are 20-fold lower compared to conventional spectrophotometry. The distinction between aqueous fullerene dispersions in comparison with organic solutions of fullerenes caused by the formation of large clusters is shown by the comparison of transient and steady-state calibration curves for aqueous and organic fullerene solutions and model reference systems under various thermal-lens excitation conditions. The advantages of thermal lensing for such colloidal systems are discussed.

  2. Aqueous Angiography: Real-Time and Physiologic Aqueous Humor Outflow Imaging

    PubMed Central

    Saraswathy, Sindhu; Tan, James C. H.; Yu, Fei; Francis, Brian A.; Hinton, David R.; Weinreb, Robert N.; Huang, Alex S.

    2016-01-01

    Purpose Trabecular meshwork (TM) bypass surgeries attempt to enhance aqueous humor outflow (AHO) to lower intraocular pressure (IOP). While TM bypass results are promising, inconsistent success is seen. One hypothesis for this variability rests upon segmental (non-360 degrees uniform) AHO. We describe aqueous angiography as a real-time and physiologic AHO imaging technique in model eyes as a way to simulate live AHO imaging. Methods Pig (n = 46) and human (n = 6) enucleated eyes were obtained, orientated based upon inferior oblique insertion, and pre-perfused with balanced salt solution via a Lewicky AC maintainer through a 1mm side-port. Fluorescein (2.5%) was introduced intracamerally at 10 or 30 mm Hg. With an angiographer, infrared and fluorescent (486 nm) images were acquired. Image processing allowed for collection of pixel information based on intensity or location for statistical analyses. Concurrent OCT was performed, and fixable fluorescent dextrans were introduced into the eye for histological analysis of angiographically active areas. Results Aqueous angiography yielded high quality images with segmental patterns (p<0.0001; Kruskal-Wallis test). No single quadrant was consistently identified as the primary quadrant of angiographic signal (p = 0.06–0.86; Kruskal-Wallis test). Regions of high proximal signal did not necessarily correlate with regions of high distal signal. Angiographically positive but not negative areas demonstrated intrascleral lumens on OCT images. Aqueous angiography with fluorescent dextrans led to their trapping in AHO pathways. Conclusions Aqueous angiography is a real-time and physiologic AHO imaging technique in model eyes. PMID:26807586

  3. Amphoteric Aqueous Hafnium Cluster Chemistry.

    PubMed

    Goberna-Ferrón, Sara; Park, Deok-Hie; Amador, Jenn M; Keszler, Douglas A; Nyman, May

    2016-05-17

    Selective dissolution of hafnium-peroxo-sulfate films in aqueous tetramethylammonium hydroxide enables extreme UV lithographic patterning of sub-10 nm HfO2 structures. Hafnium speciation under these basic conditions (pH>10), however, is unknown, as studies of hafnium aqueous chemistry have been limited to acid. Here, we report synthesis, crystal growth, and structural characterization of the first polynuclear hydroxo hafnium cluster isolated from base, [TMA]6 [Hf6 (μ-O2 )6 (μ-OH)6 (OH)12 ]⋅38 H2 O. The solution behavior of the cluster, including supramolecular assembly via hydrogen bonding is detailed via small-angle X-ray scattering (SAXS) and electrospray ionization mass spectrometry (ESI-MS). The study opens a new chapter in the aqueous chemistry of hafnium, exemplifying the concept of amphoteric clusters and informing a critical process in single-digit-nm lithography.

  4. Diagnostics of Apparent Wall Slip in Aqueous Polymer Solutions

    NASA Astrophysics Data System (ADS)

    Wein, Ondřej; Tovčigrečko, Valentin V.; Sobolík, Václav; Večeř, Marek

    2009-07-01

    Two experimental methods, apparent-wall-slip (AWS) rotational viscometry with "Morse-taper" sensors and electrodiffusion (ED) flow diagnostics with auto-calibrated friction probes, are used to study velocity profiles in aqueous solutions of high-molecular polysaccharides. By comparing the velocity data from the both methods, estimates are obtained of depleted layer thickness in dependence on wall shear stress.

  5. SEPARATION OF TECHNETIUM FROM AQUEOUS SOLUTIONS BY COPRECIPITATION WITH MAGNETITE

    DOEpatents

    Rimshaw, S.J.

    1961-10-24

    A method of separating technetium in the 4+ oxidation state from an aqueous basic solution containing products of uranium fission is described. The method consists of contacting the solution with finely divided magnetite and recovering a technetium-bearing precipitate. (AEC)

  6. NON-AQUEOUS DISSOLUTION OF MASSIVE PLUTONIUM

    DOEpatents

    Reavis, J.G.; Leary, J.A.; Walsh, K.A.

    1959-05-12

    A method is presented for obtaining non-aqueous solutions or plutonium from massive forms of the metal. In the present invention massive plutonium is added to a salt melt consisting of 10 to 40 weight per cent of sodium chloride and the balance zinc chloride. The plutonium reacts at about 800 deg C with the zinc chloride to form a salt bath of plutonium trichloride, sodium chloride, and metallic zinc. The zinc is separated from the salt melt by forcing the molten mixture through a Pyrex filter.

  7. REMOVAL OF CHLORIDE FROM AQUEOUS SOLUTIONS

    DOEpatents

    Hyman, M.L.; Savolainen, J.E.

    1960-01-01

    A method is given for dissolving reactor fuel elements in which the uranium is associated with a relatively inert chromium-containing alloy such as stainless steel. An aqueous mixture of acids comprising 2 to 2.5 molar hydrochloric acid and 4 to 8 molar nitric acid is employed in dissolving the fuel element. In order io reduce corrosion in subsequent processing of the resulting solution, chloride values are removed from the solution by contacting it with concentrated nitric acid at an elevated temperature.

  8. Aqueous Alteration of Basalts: Earth, Moon, and Mars

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.

    2007-01-01

    The geologic processes responsible for aqueous alteration of basaltic materials on Mars are modeled beginning with our knowledge of analog processes on Earth, i.e., characterization of elemental and mineralogical compositions of terrestrial environments where the alteration and weathering pathways related to aqueous activity are better understood. A key ingredient to successful modeling of aqueous processes on Mars is identification of phases that have formed by those processes. The purpose of this paper is to describe what is known about the elemental and mineralogical composition of aqueous alteration products of basaltic materials on Mars and their implications for specific aqueous environments based upon our knowledge of terrestrial systems. Although aqueous alteration has not occurred on the Moon, it is crucial to understand the behaviors of basaltic materials exposed to aqueous environments in support of human exploration to the Moon over the next two decades. Several methods or indices have been used to evaluate the extent of basalt alteration/weathering based upon measurements made at Mars by the Mars Exploration Rover (MER) Moessbauer and Alpha Particle X-Ray Spectrometers. The Mineralogical Alteration Index (MAI) is based upon the percentage of total Fe (Fe(sub T)) present as Fe(3+) in alteration products (Morris et al., 2006). A second method is the evaluation of compositional trends to determine the extent to which elements have been removed from the host rock and the likely formation of secondary phases (Nesbitt and Young, 1992; Ming et al., 2007). Most of the basalts that have been altered by aqueous processes at the two MER landing sites in Gusev crater and on Meridiani Planum have not undergone extensive leaching in an open hydrolytic system with the exception of an outcrop in the Columbia Hills. The extent of aqueous alteration however ranges from relatively unaltered to pervasively altered materials. Several experimental studies have focused upon

  9. Aqueous Processing Material Accountability Instrumentation

    SciTech Connect

    Robert Bean

    2007-09-01

    Increased use of nuclear power will require new facilities. The U.S. has not built a new spent nuclear fuel reprocessing facility for decades. Reprocessing facilities must maintain accountability of their nuclear fuel. This survey report on the techniques used in current aqueous reprocessing facilities, and provides references to source materials to assist facility design efforts.

  10. CESIUM RECOVERY FROM AQUEOUS SOLUTIONS

    DOEpatents

    Goodall, C.A.

    1960-09-13

    A process is given for precipitating cesium on zinc ferricyanide (at least 0.0004 M) from aqueous solutions containing mineral acid in a concentration of from 0.2 N acidity to 0.61 N acid-deficiency and advantageously, but not necessarily, also aluminum nitrate in a concentration of from l to 2.5 M.

  11. Aqueous-Spray Cleaning System

    NASA Technical Reports Server (NTRS)

    Morgan, Gene E.; Hoult, William S.; Simpson, Gareth L.

    1996-01-01

    Simple aqueous-spray cleaning system with overall dimensions comparable to large kitchen refrigerator constructed for use in cleaning hardware in shop. Made of commercially available parts and materials. Incorporates economical cleaner-and-rinse-recycling subsystem, as well as programmable logic-controller device for either manual or automatic operation.

  12. Antiscalant properties of Spergularia rubra and Parietaria officinalis aqueous solutions

    NASA Astrophysics Data System (ADS)

    Cheap-Charpentier, Hélène; Gelus, Dominique; Pécoul, Nathalie; Perrot, Hubert; Lédion, Jean; Horner, Olivier; Sadoun, Jonathan; Cachet, Xavier; Litaudon, Marc; Roussi, Fanny

    2016-06-01

    The formation of calcium carbonate in water has important implications in industry. Chemical antiscalant is usually used to control scale depositions. Plant extracts have been recently used as new green antiscalant agents, as they can be easily prepared and are environmentally friendly. In this study, stock aqueous solutions of Spergularia rubra and Parietaria officinalis, two plants used in traditional medicine to treat or prevent urolithiasis, were obtained by infusion. The antiscaling properties of these extracts towards CaCO3 formation were tested by using chronoamperometry and Fast Controlled Precipitation methods. The aqueous solution of S. rubra was further fractionated to isolate compounds of lower polarity. Their efficiency towards CaCO3 precipitation was characterized by Fast Controlled Precipitation method. The inhibiting efficiency of this fractionated solution was greater than that of the stock aqueous solution.

  13. Chemical reactions at aqueous interfaces

    NASA Astrophysics Data System (ADS)

    Vecitis, Chad David

    2009-12-01

    Interfaces or phase boundaries are a unique chemical environment relative to individual gas, liquid, or solid phases. Interfacial reaction mechanisms and kinetics are often at variance with homogeneous chemistry due to mass transfer, molecular orientation, and catalytic effects. Aqueous interfaces are a common subject of environmental science and engineering research, and three environmentally relevant aqueous interfaces are investigated in this thesis: 1) fluorochemical sonochemistry (bubble-water), 2) aqueous aerosol ozonation (gas-water droplet), and 3) electrolytic hydrogen production and simultaneous organic oxidation (water-metal/semiconductor). Direct interfacial analysis under environmentally relevant conditions is difficult, since most surface-specific techniques require relatively `extreme' conditions. Thus, the experimental investigations here focus on the development of chemical reactors and analytical techniques for the completion of time/concentration-dependent measurements of reactants and their products. Kinetic modeling, estimations, and/or correlations were used to extract information on interfacially relevant processes. We found that interfacial chemistry was determined to be the rate-limiting step to a subsequent series of relatively fast homogeneous reactions, for example: 1) Pyrolytic cleavage of the ionic headgroup of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) adsorbed to cavitating bubble-water interfaces during sonolysis was the rate-determining step in transformation to their inorganic constituents carbon monoxide, carbon dioxide, and fluoride; 2) ozone oxidation of aqueous iodide to hypoiodous acid at the aerosol-gas interface is the rate-determining step in the oxidation of bromide and chloride to dihalogens; 3) Electrolytic oxidation of anodic titanol surface groups is rate-limiting for the overall oxidation of organics by the dichloride radical. We also found chemistry unique to the interface, for example: 1

  14. Aqueous solubility prediction: do crystal lattice interactions help?

    PubMed

    Salahinejad, Maryam; Le, Tu C; Winkler, David A

    2013-07-01

    Aqueous solubility is a very important physical property of small molecule drugs and drug candidates but also one of the most difficult to predict accurately. Aqueous solubility plays a major role in drug delivery and pharmacokinetics. It is believed that crystal lattice interactions are important in solubility and that including them in solubility models should improve the accuracy of the models. We used calculated values for lattice energy and sublimation enthalpy of organic molecules as descriptors to determine whether these would improve the accuracy of the aqueous solubility models. Multiple linear regression employing an expectation maximization algorithm and a sparse prior (MLREM) method and a nonlinear Bayesian regularized artificial neural network with a Laplacian prior (BRANNLP) were used to derive optimal predictive models of aqueous solubility of a large and highly diverse data set of 4558 organic compounds over a normal ambient temperature range of 20-30 °C (293-303 K). A randomly selected test set and compounds from a solubility challenge were used to estimate the predictive ability of the models. The BRANNLP method showed the best statistical results with squared correlation coefficients of 0.90 and standard errors of 0.645-0.665 log(S) for training and test sets. Surprisingly, including descriptors that captured crystal lattice interactions did not significantly improve the quality of these aqueous solubility models.

  15. Characterizing Fullerene Nanoparticles in Aqueous Suspensions

    EPA Science Inventory

    Studies have indicated that fullerenes can form stable colloidal suspensions in water when introduced to the aqueous phase through solvent exchange, sonication, or extended mixing. The colloidal suspensions created using these techniques have effective aqueous phase concentratio...

  16. 21 CFR 886.3920 - Aqueous shunt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aqueous shunt. 886.3920 Section 886.3920 Food and... OPHTHALMIC DEVICES Prosthetic Devices § 886.3920 Aqueous shunt. (a) Identification. An aqueous shunt is an... Review Guidance of 2/12/90 (K90-1),” and (3) “Aqueous Shunts—510(k) Submissions.”...

  17. Sporostatic and Sporocidal Properties of Aqueous Formaldehyde

    PubMed Central

    Trujillo, Ralph; David, Thomas J.

    1972-01-01

    Aqueous formaldehyde is shown to exert both sporostatic and sporocidal effects on Bacillus subtilis spores. The sporostatic effect is a result of the reversible inhibition of spore germination occasioned by aqueous formaldehyde; the sporocidal effect is due to temperature-dependent inactivation of these spores in aqueous formaldehyde. The physicochemical state of formaldehyde in solution provides a framework with which to interpret both the sporostatic and sporocidal properties of aqueous formaldehyde. PMID:4623282

  18. Multi-instrumental characterization of carbon nanotubes dispersed in aqueous solutions

    EPA Science Inventory

    Previous studies showed that the dispersion extent and physicochemical properties of carbon nanotubes are highly dependent upon the preparation methods (e.g., dispersion methods and dispersants). In the present work, multiwalled carbon nanotubes (MWNTs) are dispersed in aqueous s...

  19. Non-Aqueous Phase Liquid Calculator

    2004-02-19

    Non-Aqueous Phase Liquid or "NPAL" is a term that most environmental professionals are familiar with because NAPL has been recognized in the literature as a significant source of groundwater contamination. There are two types of NAPL: DNAPL and LNAPL. DNAPL is a ‘dense’ non-aqueous phase liquid. In this context, dense means having a density greater than water (1.0 kg/L). Trichloroethylene (TCE) and tetrachioroethylene (PCE) are examples of DNAPL compounds. A compound that is heaver thanmore » water means this type of NAPL will sink in an aquifer. Conversely, LNAPL is a ‘light’ non-aqueous phase liquid with a density less than water, and will float on top of the aquifer. Examples of LNAPL’s are benzene and toluene. LNAPL or DNAPL often manifest as a complex, multi-component mixture of organic compounds that can occur in environmental media. Complex multi-component mixtures distributed in soil pore-air, pore-water, soil particles and in free phase complicate residual saturation of single and multi component NAPL compounds in soil samples. The model output also includes estimates of the NAPL mass and volume and other physical and chemical properties that may be useful for characterization, modeling, and remedial system design and operation. The discovery of NAPL in the aquifer usually leads to a focused characterization for possible sources of NAPL in the vadose zone using a variety of innovative technologies and characterization methods. Often, the analytical data will indicated the presence of NAPL, yet, the NAPL will go unrecognized. Failure to recognize the NAPL can be attributed to the complicated processes of inter-media transfer or a general lack of knowledge about the physical characteristics of complex organic mixtures in environmental samples.« less

  20. Removal of phosphate from aqueous solutions by electro-coagulation.

    PubMed

    Bektaş, Nihal; Akbulut, Hilal; Inan, Hatice; Dimoglo, Anatoly

    2004-01-30

    The aim of this paper was to investigate the feasibility of the removal of phosphate from aqueous solution by electro-coagulation (EC). The current density (CD) between 2.5 and 10 mA cm(-2) and duration in the limits of 5-20 min were tried for different concentrations. In order to determine optimal operating conditions, the EC process used for the phosphate removal was examined in dependence with the CD, initial concentrations and time. The results of the experimental batch processing showed high effectiveness of the EC method in removing phosphate from aqueous solutions. PMID:15177098

  1. Thermally responsive aqueous silicate mixtures and use thereof

    SciTech Connect

    Smith, W.H.; Vinson, E.F.

    1987-02-03

    A method is described of plugging or sealing a zone in a subterranean formation comprising: (a) contacting the zone with an aqueous silicate composition consisting essentially of (i) an aqueous solution containing an alkali metal silicate; and, (ii) a thermally responsive gelation activator selected from the group consisting of lactose, dextrose, fructose, galactose, mannose, mantose, xylose and mixtures thereof; and (b) activating the gelation activator in response to a thermal change in the composition within the formation whereby the silicate composition is caused to form a gel in the zone.

  2. Continuous real-time measurement of aqueous cyanide

    DOEpatents

    Rosentreter, Jeffrey J.; Gering, Kevin L.

    2007-03-06

    This invention provides a method and system capable of the continuous, real-time measurement of low concentrations of aqueous free cyanide (CN) using an on-line, flow through system. The system is based on the selective reactivity of cyanide anions and the characteristically nonreactive nature of metallic gold films, wherein this selective reactivity is exploited as an indirect measurement for aqueous cyanide. In the present invention the dissolution of gold, due to the solubilization reaction with the analyte cyanide anion, is monitored using a piezoelectric microbalance contained within a flow cell.

  3. Removal of phosphate from aqueous solutions by electro-coagulation.

    PubMed

    Bektaş, Nihal; Akbulut, Hilal; Inan, Hatice; Dimoglo, Anatoly

    2004-01-30

    The aim of this paper was to investigate the feasibility of the removal of phosphate from aqueous solution by electro-coagulation (EC). The current density (CD) between 2.5 and 10 mA cm(-2) and duration in the limits of 5-20 min were tried for different concentrations. In order to determine optimal operating conditions, the EC process used for the phosphate removal was examined in dependence with the CD, initial concentrations and time. The results of the experimental batch processing showed high effectiveness of the EC method in removing phosphate from aqueous solutions.

  4. Catalytic activities of zeolite compounds for decomposing aqueous ozone.

    PubMed

    Kusuda, Ai; Kitayama, Mikito; Ohta, Yoshio

    2013-12-01

    The advanced oxidation process (AOP), chemical oxidation using aqueous ozone in the presence of appropriate catalysts to generate highly reactive oxygen species, offers an attractive option for removing poorly biodegradable pollutants. Using the commercial zeolite powders with various Si/Al ratios and crystal structures, their catalytic activities for decomposing aqueous ozone were evaluated by continuously flowing ozone to water containing the zeolite powders. The hydrophilic zeolites (low Si/Al ratio) with alkali cations in the crystal structures were found to possess high catalytic activity for decomposing aqueous ozone. The hydrophobic zeolite compounds (high Si/Al ratio) were found to absorb ozone very well, but to have no catalytic activity for decomposing aqueous ozone. Their catalytic activities were also evaluated by using the fixed bed column method. When alkali cations were removed by acid rinsing or substituted by alkali-earth cations, the catalytic activities was significantly deteriorated. These results suggest that the metal cations on the crystal surface of the hydrophilic zeolite would play a key role for catalytic activity for decomposing aqueous ozone.

  5. The ultrasound-assisted aqueous extraction of rice bran oil.

    PubMed

    Khoei, Maryam; Chekin, Fereshteh

    2016-03-01

    In this work, aqueous extraction of rice bran oil was done without and with ultrasound pretreatment. Key factors controlling the extraction and optimal operating conditions were identified. The highest extraction efficiency was found at pH=12, temperature of 45°C, agitation speed of 800rpm and agitation time of 15min, ultrasound treatment time of 70min and ultrasound treatment temperature of 25°C. Moreover, extraction yields were compared to ultrasound-assisted aqueous extraction and Soxhlet extraction. The results showed that the yield of rice bran oil at ultrasound-assisted aqueous extraction was close to the yield of oil extracted by hexane Soxhlet extraction. This result implied that the yield of rice bran oil was significantly influenced by ultrasound. With regard to quality, the oil extracted by ultrasound-assisted aqueous process had a lower content of free fatty acid and lower color imparting components than the hexane-extracted oil. Also, effect of parboiling of paddy on hexane and ultrasound-assisted aqueous extraction was studied. Both extraction methods gives higher percentage of oil from par boiled rice bran compared with raw rice bran. This may be due to the fact that parboiling releases the oil.

  6. Catalytic activities of zeolite compounds for decomposing aqueous ozone.

    PubMed

    Kusuda, Ai; Kitayama, Mikito; Ohta, Yoshio

    2013-12-01

    The advanced oxidation process (AOP), chemical oxidation using aqueous ozone in the presence of appropriate catalysts to generate highly reactive oxygen species, offers an attractive option for removing poorly biodegradable pollutants. Using the commercial zeolite powders with various Si/Al ratios and crystal structures, their catalytic activities for decomposing aqueous ozone were evaluated by continuously flowing ozone to water containing the zeolite powders. The hydrophilic zeolites (low Si/Al ratio) with alkali cations in the crystal structures were found to possess high catalytic activity for decomposing aqueous ozone. The hydrophobic zeolite compounds (high Si/Al ratio) were found to absorb ozone very well, but to have no catalytic activity for decomposing aqueous ozone. Their catalytic activities were also evaluated by using the fixed bed column method. When alkali cations were removed by acid rinsing or substituted by alkali-earth cations, the catalytic activities was significantly deteriorated. These results suggest that the metal cations on the crystal surface of the hydrophilic zeolite would play a key role for catalytic activity for decomposing aqueous ozone. PMID:25078817

  7. The ultrasound-assisted aqueous extraction of rice bran oil.

    PubMed

    Khoei, Maryam; Chekin, Fereshteh

    2016-03-01

    In this work, aqueous extraction of rice bran oil was done without and with ultrasound pretreatment. Key factors controlling the extraction and optimal operating conditions were identified. The highest extraction efficiency was found at pH=12, temperature of 45°C, agitation speed of 800rpm and agitation time of 15min, ultrasound treatment time of 70min and ultrasound treatment temperature of 25°C. Moreover, extraction yields were compared to ultrasound-assisted aqueous extraction and Soxhlet extraction. The results showed that the yield of rice bran oil at ultrasound-assisted aqueous extraction was close to the yield of oil extracted by hexane Soxhlet extraction. This result implied that the yield of rice bran oil was significantly influenced by ultrasound. With regard to quality, the oil extracted by ultrasound-assisted aqueous process had a lower content of free fatty acid and lower color imparting components than the hexane-extracted oil. Also, effect of parboiling of paddy on hexane and ultrasound-assisted aqueous extraction was studied. Both extraction methods gives higher percentage of oil from par boiled rice bran compared with raw rice bran. This may be due to the fact that parboiling releases the oil. PMID:26471585

  8. Hypoglycemic Activity of Aqueous Extracts from Catharanthus roseus

    PubMed Central

    Vega-Ávila, Elisa; Cano-Velasco, José Luis; Alarcón-Aguilar, Francisco J.; Fajardo Ortíz, María del Carmen; Almanza-Pérez, Julio César; Román-Ramos, Rubén

    2012-01-01

    Introduction. Catharanthus roseus (L.) is used in some countries to treat diabetes. The aim of this study was to evaluate the hypoglycemic activity of extracts from the flower, leaf, stem, and root in normal and alloxan-induced diabetic mice. Methods. Roots, leaves, flowers, and stems were separated to obtain organic and aqueous extracts. The blood glucose lowering activity of these extracts was determinate in healthy and alloxan-induced (75 mg/Kg) diabetic mice, after intraperitoneal administration (250 mg/Kg body weight). Blood samples were obtained and blood glucose levels were analyzed employing a glucometer. The data were statistically compared by ANOVA. The most active extract was fractioned. Phytochemical screen and chromatographic studies were also done. Results. The aqueous extracts from C. roseus reduced the blood glucose of both healthy and diabetic mice. The aqueous stem extract (250 mg/Kg) and its alkaloid-free fraction (300 mg/Kg) significantly (P < 0.05) reduced blood glucose in diabetic mice by 52.90 and 51.21%. Their hypoglycemic activity was comparable to tolbutamide (58.1%, P < 0.05). Conclusions. The best hypoglycemic activity was presented for the aqueous extracts and by alkaloid-free stem aqueous fraction. This fraction is formed by three polyphenols compounds. PMID:23056144

  9. Cesium recovery from aqueous solutions

    DOEpatents

    Goodhall, C. A.

    1960-09-13

    A process for recovering cesium from aqueous solutions is given in which precipitation on zinc ferricyanide is used. The precipitation is preferably carried out in solutions containing at least 0.0004M zinc ferricyanide, an acidity ranging from 0.2N mineral acid to 0.61N acid deficiency, and 1 to 2.5M aluminum nitrate. (D.L.C.)

  10. The Melting of Aqueous Foams

    NASA Technical Reports Server (NTRS)

    Durian, Douglas J.; Gopal, Anthony D.; Vera, Moin U.; Langer, Stephen A.

    1996-01-01

    Diffusing-wave spectroscopy measurements show that ordinarily solid aqueous foams flow by a series of stick-slip avalanche-like rearrangements of neighboring bubbles from one tight packing configuration to another. Contrary to a recent prediction, the distribution of avalanche sizes do not obey a power-law distribution characteristic of self-organized criticality. This can be understood from a simple model of foam mechanics based on bubble-bubble interactions.

  11. Stabilized aqueous hydrogen peroxide solution

    SciTech Connect

    Malin, M.J.; Sciafani, L.D.

    1988-05-17

    This patent describes a stabilized aqueous hydrogen peroxide solution having a pH below 7 and an amount of Ferric ion up to about 2 ppm comprising hydrogen peroxide, acetanilide having a concentration which ranges between 0.74 M Mol/L and 2.22 mMol/L, and o-benzene disulfonic acid or salt thereof at a concentration between about 0.86 mMol/L to about 1.62 mMol/L.

  12. Geochemical Modeling Of Aqueous Systems

    1995-09-07

    EQ3/6 is a software package for geochemical modeling of aqueous systems. This description pertains to version 7.2b. It addresses aqueous speciation, thermodynamic equilibrium, disequilibrium, and chemical kinetics. The major components of the package are EQ3NR, a speciation-solubility code, and EQ6 a reaction path code. EQ3NR is useful for analyzing groundwater chemistry data, calculating solubility limits, and determining whether certain reactions are in states of equilibrium or disequilibrium. It also initializes EQ6 calculations. EQ6 models themore » consequences of reacting an aqueous solution with a specified set of reactants (e.g., minerals or waste forms). It can also model fluid mixing and the effects of changes in temperature. Each of five supporting data files contain both standard state and activity coefficient-related data. Three support the use of the Davies or B-dot equations for the activity coefficients; the other two support the use of Pitzer''s equations. The temperature range of the thermodynamic data on the data files varies from 25 degrees C only to 0-300 degrees C.« less

  13. Aqueous enzymatic extraction of Moringa oleifera oil.

    PubMed

    Mat Yusoff, Masni; Gordon, Michael H; Ezeh, Onyinye; Niranjan, Keshavan

    2016-11-15

    This paper reports on the extraction of Moringa oleifera (MO) oil by using aqueous enzymatic extraction (AEE) method. The effect of different process parameters on the oil recovery was discovered by using statistical optimization, besides the effect of selected parameters on the formation of its oil-in-water cream emulsions. Within the pre-determined ranges, the use of pH 4.5, moisture/kernel ratio of 8:1 (w/w), and 300stroke/min shaking speed at 40°C for 1h incubation time resulted in highest oil recovery of approximately 70% (goil/g solvent-extracted oil). These optimized parameters also result in a very thin emulsion layer, indicating minute amount of emulsion formed. Zero oil recovery with thick emulsion were observed when the used aqueous phase was re-utilized for another AEE process. The findings suggest that the critical selection of AEE parameters is key to high oil recovery with minimum emulsion formation thereby lowering the load on the de-emulsification step. PMID:27283648

  14. Aqueous alternatives for metal and composite cleaning

    NASA Technical Reports Server (NTRS)

    Quitmeyer, Joann

    1994-01-01

    For many years the metalworking industry has cleaned metal and composite substrates with chlorinated solvents. Recently, however, health and disposal related environmental concerns have increased regarding chlorinated solvents, including 1,1,1-trichloroethane, trichloroethylene, methylene chloride, or Freon'. World leaders have instituted a production ban of certain ozone depleting chlorofluorocarbons (CFC's) by 1996. The Occupational Safety and Health Administration (OSHA) has instituted worker vapor exposure limitations for virtually all of the solvents used in solvent-based cleaners. In addition, the United States Environmental Protection Agency (EPA) has defined nearly all solvent-based cleaners as 'hazardous'. Cradle to grave waste responsibility is another reason manufacturers are trying to replace chlorinated solvents in their cleaning processes. Because of these factors, there now is a world wide effort to reduce and/or eliminate the use of chlorinated solvents for industrial cleaning. Waterbased cleaners are among the alternatives being offered to the industry. New technology alkaline cleaners are now available that can be used instead of chlorinated solvents in many cleaning processes. These waterbased cleaners reduce the release of volatile organic compounds (VOC's) by as much as 99 percent. (The definition and method of calculation of VOC's now varies from region to region.) Hazardous waste generation can also be significantly reduced or eliminated with new aqueous technology. This in turn can ease worker exposure restrictions and positively impact the environment. This paper compares the chemical and physical properties of this aqueous cleaners versus chlorinated solvents.

  15. Aqueous enzymatic extraction of Moringa oleifera oil.

    PubMed

    Mat Yusoff, Masni; Gordon, Michael H; Ezeh, Onyinye; Niranjan, Keshavan

    2016-11-15

    This paper reports on the extraction of Moringa oleifera (MO) oil by using aqueous enzymatic extraction (AEE) method. The effect of different process parameters on the oil recovery was discovered by using statistical optimization, besides the effect of selected parameters on the formation of its oil-in-water cream emulsions. Within the pre-determined ranges, the use of pH 4.5, moisture/kernel ratio of 8:1 (w/w), and 300stroke/min shaking speed at 40°C for 1h incubation time resulted in highest oil recovery of approximately 70% (goil/g solvent-extracted oil). These optimized parameters also result in a very thin emulsion layer, indicating minute amount of emulsion formed. Zero oil recovery with thick emulsion were observed when the used aqueous phase was re-utilized for another AEE process. The findings suggest that the critical selection of AEE parameters is key to high oil recovery with minimum emulsion formation thereby lowering the load on the de-emulsification step.

  16. Enhanced Oil Recovery: Aqueous Flow Tracer Measurement

    SciTech Connect

    Joseph Rovani; John Schabron

    2009-02-01

    A low detection limit analytical method was developed to measure a suite of benzoic acid and fluorinated benzoic acid compounds intended for use as tracers for enhanced oil recovery operations. Although the new high performance liquid chromatography separation successfully measured the tracers in an aqueous matrix at low part per billion levels, the low detection limits could not be achieved in oil field water due to interference problems with the hydrocarbon-saturated water using the system's UV detector. Commercial instrument vendors were contacted in an effort to determine if mass spectrometry could be used as an alternate detection technique. The results of their work demonstrate that low part per billion analysis of the tracer compounds in oil field water could be achieved using ultra performance liquid chromatography mass spectrometry.

  17. Toxicity of calcium salts to aqueous microorganisms

    SciTech Connect

    Lakhina, K.G.; Dolganova, A.V.; Yakobi, L.K.

    1983-03-01

    This article investigates the toxicity of calcium to aqueous microogranisms by means of a procedure developed by VNII VODGEO (All-Union Scientific-Research Institute of Water Supply, Sewer Systems, Hydrotechnical Facilities, and Engineering Hydrogeology), with certain changes in the preparation of the culture water. Proposes that with this method, calcium toxicity can be determined for groups of microorganisms that are among the most important in biochemical wastewater treatment and self-purification of water bodies (saprophytes, phase I and II nitrifiers). Finds that calcium in the form of the hydroxide and chloride is nontoxic under the following conditions: for protozoa in concentrations up to 2 g/liter, for saprophytic bacteria up to 3 g/liter, for phase I nitrifiers up to 1 g/liter, and for phase II nitrifiers up to 0.1 g/liter.

  18. Photodegradation of acetone in dilute aqueous solution

    SciTech Connect

    Stefan, M.I.; Bolton, J.R.

    1995-12-31

    Photochemical methods for destroying organic pollutants found in industrial wastewaters and groundwaters are being used successfully in environment treatment systems. This study focuses on acetone photodegradation in aqueous solution by UV irradiation (1 kW medium pressure Hg lamp) in the presence and absence of H{sub 2}O{sub 2}. Intermediates such as acetic and formic acids were detected. The kinetic data were evaluated and the reaction mechanisms were postulated considering the influence of oxygen concentration and pH. The generation of {sm_bullet}OH radicals from the photolysis of H{sub 2}O{sub 2} induces a faster decomposition of acetone (depending on H{sub 2}O{sub 2} concentration) than does direct photolysis.

  19. CESIUM RECOVERY FROM AQUEOUS SOLUTIONS

    DOEpatents

    Schneider, R.A.

    1961-06-20

    Cesium may be precipitated from an aqueous solution whose acidity ranges between a pH of 1.5 and a molarity of 5 on cobaltous, zinc, cadmium, nickel, or ferrous cobalticyanide. This precipitation brings about a separation from most fission products. Ruthenium which coprecipitates to a great degree can be removed by dissolving in sulfuric acid and boiling the solution in the presence of periodic acid for volatilization; other coprecipitated fission products can then be precipitated from the sulfuric acid solution with a ferric hydroxide carrier.

  20. Supramolecular Polymers in Aqueous Media.

    PubMed

    Krieg, Elisha; Bastings, Maartje M C; Besenius, Pol; Rybtchinski, Boris

    2016-02-24

    This review discusses one-dimensional supramolecular polymers that form in aqueous media. First, naturally occurring supramolecular polymers are described, in particular, amyloid fibrils, actin filaments, and microtubules. Their structural, thermodynamic, kinetic, and nanomechanical properties are highlighted, as well as their importance for the advancement of biologically inspired supramolecular polymer materials. Second, five classes of synthetic supramolecular polymers are described: systems based on (1) hydrogen-bond motifs, (2) large π-conjugated surfaces, (3) host-guest interactions, (4) peptides, and (5) DNA. We focus on recent studies that address key challenges in the field, providing mechanistic understanding, rational polymer design, important functionality, robustness, or unusual thermodynamic and kinetic properties. PMID:26727633

  1. Bimatoprost Effects on Aqueous Humor Dynamics in Monkeys

    PubMed Central

    Woodward, David F.; Krauss, Achim H.-P.; Nilsson, Siv F. E.

    2010-01-01

    The effects of bimatoprost on aqueous humor dynamics were quantified in monkey eyes. Uveoscleral outflow was measured by the anterior chamber perfusion method, using FITC-dextran. Total outflow facility was determined by the two-level constant pressure method. Aqueous flow was measured with a scanning ocular fluorophotometer. Uveoscleral outflow was 0.96 ± 0.19 μL min−1 in vehicle-treated eyes and 1.37 ± 0.27 μL min−1 (n = 6; P < .05) in eyes that received bimatoprost 0.01% b.i.d. × 5 days. Bimatoprost had no effect on total outflow facility, which was 0.42 ± 0.05 μL min−1 at baseline and 0.42 ± 0.04 μL min−1 after bimatoprost treatment. Bimatoprost had no significant effect on aqueous humor flow. This study demonstrates that bimatoprost increases uveoscleral outflow but not total outflow facility or aqueous humor flow, indicating that it lowers intraocular pressure in ocular normotensive monkeys by a mechanism that exclusively involves uveoscleral outflow. PMID:20508775

  2. Simple, benign, aqueous-based amination of polycarbonate surfaces

    SciTech Connect

    VanDelinder, Virginia; Wheeler, David R.; Small, Leo J.; Brumbach, Michael T.; Spoerke, Erik D.; Henderson, Ian; Bachand, George D.

    2015-03-18

    Here we report a simple, safe, environmentally-friendly aqueous method that uses diamines to functionalize a polycarbonate surface with amino groups. We demonstrate the ability of this facile method to serve as a foundation upon which other functionalities may be attached, including anti-fouling coatings and oriented membrane proteins. The use of water as the solvent for the functionalization ensures that solvent induced swelling does not affect the optical or mechanical properties of the polycarbonate.

  3. Non-aqueous solution preparation of doped and undoped lixmnyoz

    DOEpatents

    Boyle, Timothy J.; Voigt, James A.

    1997-01-01

    A method for generation of phase-pure doped and undoped Li.sub.x Mn.sub.y O.sub.z precursors. The method of this invention uses organic solutions instead of aqueous solutions or nonsolution ball milling of dry powders to produce phase-pure precursors. These precursors can be used as cathodes for lithium-polymer electrolyte batteries. Dopants may be homogeneously incorporated to alter the characteristics of the powder.

  4. Ultrasound induced aqueous polycyclic aromatic hydrocarbon reactivity.

    PubMed

    Wheat, P E; Tumeo, M A

    1997-01-01

    An investigation to determine the ability of ultrasonic radiation to chemically alter polycyclic aromatic hydrocarbons (PAHs) in aqueous solution has been conducted. The data indicate that chemical alteration of PAHs can be induced under intense ultrasonic treatment. The extent and outcome of reaction is a function of irridation time and aqueous solution parameters. Reaction products were analysed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Reaction products from ultrasonic treatment of aqueous solutions of biphenyl include ortho, meta, and para-1,1 biphenols. The principal product from ultrasonic treatment of aqueous phenanthrene solutions appears to be a phenanthrene-diol. The number and composition of reaction products for both PAHs tested suggest that a free radical mechanism is likely during aqueous high intensity ultrasonic treatment. The use of ultrasound to treat PAH contaminated aqueous solutions in tandem with other methodologies appears promising. However, the toxicity of reaction products produced by treatment remains to be determined. PMID:11233926

  5. Aqueous nanosilica dispersants for carbon nanotube.

    PubMed

    Matsuda, Takafumi; Minami, Daiki; Khoerunnisa, Fitri; Sunaga, Motoo; Nakamura, Masahiro; Utsumi, Shigenori; Itoh, Tsutomu; Fujimori, Toshihiko; Hayashi, Takuya; Hattori, Yoshiyuki; Endo, Morinobu; Isobe, Hiroshi; Onodera, Hiroshi; Kaneko, Katsumi

    2015-03-17

    Nanosilicas can disperse single-wall carbon nanotube (SWCNT) in aqueous solution efficiently; SWCNTs are stably dispersed in aqueous media for more than 6 months. The SWCNT dispersing solution with nanosilica can produce highly conductive transparent films which satisfy the requirements for application to touch panels. Even multiwall carbon nanotube can be dispersed easily in aqueous solution. The highly stable dispersion of SWCNTs in the presence of nanosilica is associated with charge transfer interaction which generates effective charges on the SWCNT particles, giving rise to electrostatic repulsion between the SWCNTs in the aqueous solution. Adhesion of charged nanosilicas on SWCNTs in the aqueous solution and a marked depression of the S11 peak of optical absorption spectrum of the SWCNT with nanosilicas suggest charge transfer interaction of nanosilicas with SWCNT. Thus-formed isolated SWCNTs are fixed on the flexible three-dimensional silica jelly structure in the aqueous solution, leading to the uniform and stable dispersion of SWCNTs. PMID:25706991

  6. Dimensional analysis of aqueous magnetic fluids

    NASA Astrophysics Data System (ADS)

    Răcuciu, M.; Creangă, D. E.; Suliţanu, N.; Bădescu, V.

    2007-11-01

    A comparison of the synthesis and characterization of three aqueous magnetic fluids intended for biomedical applications is presented. Stable colloidal suspensions of iron oxide nanoparticles were prepared by a co-precipitation method with the magnetite cores being coated with β-cyclodextrin, tetramethylammonium hydroxide and citric acid. Rheological properties of the fluids were investigated, i.e. viscosity (capillary method) and surface tension (stalagmometric method) in correlation with their density (picnometric method). The dimensional distributions of the ferrophase particles physical diameter of these three magnetic fluids - revealed on the basis of transmission electron microscopy (TEM) data - as well as the diameter distributions of some other magnetic fluids presented in the literature, were comparatively analyzed using the box-plot statistical method. In order to extract complementary data on the magnetic diameter of an iron oxide core, magnetization measurements as well as X-ray diffraction pattern analysis were carried out. Interpretation of all the measurement data was accomplished by assessing the suitability of the three magnetic fluid samples from the viewpoint of their stability and biocompatibility.

  7. Aqueous Rechargeable Zinc/Aluminum Ion Battery with Good Cycling Performance.

    PubMed

    Wang, Faxing; Yu, Feng; Wang, Xiaowei; Chang, Zheng; Fu, Lijun; Zhu, Yusong; Wen, Zubiao; Wu, Yuping; Huang, Wei

    2016-04-13

    Developing rechargeable batteries with low cost is critically needed for the application in large-scale stationary energy storage systems. Here, an aqueous rechargeable zinc//aluminum ion battery is reported on the basis of zinc as the negative electrode and ultrathin graphite nanosheets as the positive electrode in an aqueous Al2(SO4)3/Zn(CHCOO)2 electrolyte. The positive electrode material was prepared through a simple electrochemically expanded method in aqueous solution. The cost for the aqueous electrolyte together with the Zn negative electrode is low, and their raw materials are abundant. The average working voltage of this aqueous rechargeable battery is 1.0 V, which is higher than those of most rechargeable Al ion batteries in an ionic liquid electrolyte. It could also be rapidly charged within 2 min while maintaining a high capacity. Moreover, its cycling behavior is also very good, with capacity retention of nearly 94% after 200 cycles.

  8. Formaldehyde migration in aqueous extracts from paper and cardboard food packaging materials in Turkey.

    PubMed

    Dogan, Canan Ekinci; Sancı, Rukiye

    2015-01-01

    Migration of formaldehyde to aqueous extracts from paper and cardboard food packaging materials was determined by an ultraviolet visible-spectrophotometric method at 410 nm. Intraday and interday precision of the method, expressed as coefficient of variation, varied between 1.5 to 4.4% and 7 to 8.8%, respectively. The limit of quantification was 0.28 mg kg(-1) for formaldehyde in aqueous extracts. The recovery of the method was over 90% for two different concentration levels in aqueous extracts. The method was applied to the migration of formaldehyde to aqueous extracts from 31 different paper and cardboard materials collected from the packaging sector, intended for food contact, such as tea filters, hot water filters, paper pouches and folding boxes. The results were between limit of detection 0.23 mg/kg and 40 mg kg(-1) and were evaluated according to the relevant directives.

  9. Processing of Primordial Organic Compounds in Carbonaceous Chondrites by mild Aqueous Alteration

    NASA Astrophysics Data System (ADS)

    Trigo-Rodriguez, J. M.; Martins, Z.; Rimola, A.

    2016-08-01

    New evidence suggests a synthesis of complex organic species in water-rich undifferentiated bodies. Quantum mechanical methods are compared with experimental data to see if organic matter was processed by clay formation during aqueous alteration.

  10. Aqueous biphasic plutonium oxide extraction process with pH and particle control

    DOEpatents

    Chaiko, D.J.; Mensah-Biney, R.

    1997-04-29

    A method is described for simultaneously partitioning a metal oxide and silica from a material containing silica and the metal oxide, using a biphasic aqueous medium having immiscible salt and polymer phases. 2 figs.

  11. Application of aqueous two-phase systems for the development of a new method of cobalt(II), iron(III) and nickel(II) extraction: a green chemistry approach.

    PubMed

    Patrício, Pamela da Rocha; Mesquita, Maiby Cabral; da Silva, Luis Henrique Mendes; da Silva, Maria C Hespanhol

    2011-10-15

    We have investigated the extraction behavior of the metallic ions Co(II), Fe(III) and Ni(II) as a function of the amount of potassium thiocyanate used as an extracting agent, using the following aqueous two-phase systems (ATPS): PEO + (NH(4))(2)SO(4) + H(2)O, PEO + Li(2)SO(4) + H(2)O, L35 + (NH(4))(2)SO(4) + H(2)O and L35 + (Li)(2)SO(4)+H(2)O. Metal extraction from the salt-rich phase to the polymer-rich phase is affected by the following parameters: amount of added extractant, pH, and the nature of the electrolyte and polymer that forms the ATPS. Maximal extraction percentages were obtained for Co(II) (99.8%), Fe(III) (12.7%) and Ni(II) (3.17%) when the ATPS was composed of PEO1500 + (NH(4))(2)SO(4) + H(2)O containing 1.4 mmol of KSCN at pH 4.0, providing separation factors as high as S(Co, Fe) = 3440 and S(Co, Ni) = 15,300. However, when the same ATPS was used at pH 2.0, the maximal extraction percentages for iron and nickel were 99.5% and 4.34%, respectively, with S(Fe, Ni) equal to 4380. The proposed technique was shown to be efficient in the extraction of Co(II) and Fe(III), with large viability for the selective separation of Co(II) and Fe(III) ions in the presence of Ni(II). PMID:21864977

  12. Application of aqueous two-phase systems for the development of a new method of cobalt(II), iron(III) and nickel(II) extraction: a green chemistry approach.

    PubMed

    Patrício, Pamela da Rocha; Mesquita, Maiby Cabral; da Silva, Luis Henrique Mendes; da Silva, Maria C Hespanhol

    2011-10-15

    We have investigated the extraction behavior of the metallic ions Co(II), Fe(III) and Ni(II) as a function of the amount of potassium thiocyanate used as an extracting agent, using the following aqueous two-phase systems (ATPS): PEO + (NH(4))(2)SO(4) + H(2)O, PEO + Li(2)SO(4) + H(2)O, L35 + (NH(4))(2)SO(4) + H(2)O and L35 + (Li)(2)SO(4)+H(2)O. Metal extraction from the salt-rich phase to the polymer-rich phase is affected by the following parameters: amount of added extractant, pH, and the nature of the electrolyte and polymer that forms the ATPS. Maximal extraction percentages were obtained for Co(II) (99.8%), Fe(III) (12.7%) and Ni(II) (3.17%) when the ATPS was composed of PEO1500 + (NH(4))(2)SO(4) + H(2)O containing 1.4 mmol of KSCN at pH 4.0, providing separation factors as high as S(Co, Fe) = 3440 and S(Co, Ni) = 15,300. However, when the same ATPS was used at pH 2.0, the maximal extraction percentages for iron and nickel were 99.5% and 4.34%, respectively, with S(Fe, Ni) equal to 4380. The proposed technique was shown to be efficient in the extraction of Co(II) and Fe(III), with large viability for the selective separation of Co(II) and Fe(III) ions in the presence of Ni(II).

  13. Safety and antidiarrheal activity of Priva adhaerens aqueous leaf extract in a murine model

    PubMed Central

    Nansunga, Miriam; Barasa, Ambrose; Abimana, Justus; Alele, Paul E.; Kasolo, Josephine

    2014-01-01

    Ethnopharmacological relevance Priva adhaerens (Forssk.) Chiov., a wildly growing plant, is reported in central Uganda to be an effective traditional remedy for diarrhea. The objective of this study was to provide a scientific basis for the ethnopharmacological utility of this plant whose aqueous leaf and shoot extract was evaluated for acute toxicity and antidiarrheal activity using a murine model. Materials and methods Acute toxicity of the aqueous leaf and shoot extract was assessed after determining the major phytochemicals present in the extract. The aqueous leaf and shoot extract was assayed against castor oil-induced diarrhea, transit time, and enteropooling, in comparison to loperamide, a standard drug. Results The oral LD50 value obtained for Priva adhaerens aqueous extract was greater than 5000 mg/kg in rats; the aqueous leaf and shoot extract possessed several important phytochemicals. Furthermore, the aqueous extract significantly, and dose-dependently, reduced frequency of stooling in castor oil-induced diarrhea, intestinal motility, and castor oil-induced enteropooling in rats. Conclusion This murine model shows that it is relatively safe to orally use the aqueous leaf and shoot extract of Priva adhaerens . The aqueous extract contains phytochemicals that are active for the treatment of diarrhea in a rat model. PMID:25304198

  14. Spiers Memorial Lecture. Ions at aqueous interfaces.

    PubMed

    Jungwirth, Pavel

    2009-01-01

    Studies of aqueous interfaces and of the behavior of ions therein have been profiting from a recent remarkable progress in surface selective spectroscopies, as well as from developments in molecular simulations. Here, we summarize and place in context our investigations of ions at aqueous interfaces employing molecular dynamics simulations and electronic structure methods, performed in close contact with experiment. For the simplest of these interfaces, i.e. the open water surface, we demonstrate that the traditional picture of an ion-free surface is not valid for large, soft (polarizable) ions such as the heavier halides. Both simulations and spectroscopic measurements indicate that these ions can be present and even enhanced at surface of water. In addition we show that the ionic product of water exhibits a peculiar surface behavior with hydronium but not hydroxide accumulating at the air/water and alkane/water interfaces. This result is supported by surface-selective spectroscopic experiments and surface tension measurements. However, it contradicts the interpretation of electrophoretic and titration experiments in terms of strong surface adsorption of hydroxide; an issue which is further discussed here. The applicability of the observed behavior of ions at the water surface to investigations of their affinity for the interface between proteins and aqueous solutions is explored. Simulations show that for alkali cations the dominant mechanism of specific interactions with the surface of hydrated proteins is via ion pairing with negatively charged amino acid residues and with the backbone amide groups. As far as halide anions are concerned, the lighter ones tend to pair with positively charged amino acid residues, while heavier halides exhibit affinity to the amide group and to non-polar protein patches, the latter resembling their behavior at the air/water interface. These findings, together with results for more complex molecular ions, allow us to formulate a

  15. SEPARATION OF POLONIUM, PROTACTINIUM OR MIXTURES THEREOF IN AQUEOUS SOLUTION FROM BISMUTH, LEAD, ZIRCONIUM AND/OR COLUMBIUM VALUES

    DOEpatents

    Van Winkle, Q.; Kraus, K.A.

    1959-10-27

    A process is presented for separating polonium, protactinium, or mixtures thereof in aqueous solution from bismuth, zirconium, lead, and niobium values contained in the solution. The method comprises providing hydrochloric acid in the solution in a concentration of at least 5N. contacting the aqueous solution with a substantially waterimmiscible organic solvent such as diisopropyl ketone, and separating the aqueous phase containing the bismuth, zirconium, lead, and niobium from the organic extract phase containing the polonium, protactinium, or mixture thereof.

  16. Proteome Analysis of Human Aqueous Humor

    PubMed Central

    Chowdhury, Uttio Roy; Madden, Benjamin J.; Charlesworth, Mary Christine

    2010-01-01

    Purpose. Human aqueous humor (hAH) provides nutrition and immunity within the anterior chamber of the eye. Characterization of the protein composition of hAH will identify molecules involved in maintaining a homeostatic environment for anterior segment tissues. The present study was conducted to analyze the proteome of hAH. Methods. hAH samples obtained during elective cataract surgery were divided into three matched groups and immunodepleted of albumin, IgG, IgA, haploglobin, antitrypsin, and transferrin. Reduced and denatured proteins (20 μg) from each group were separated by gel electrophoresis. Thirty-three gel slices were excised from each of three gel lanes (n = 99), digested with trypsin, and subjected to nanoflow liquid chromatography electrospray ionization tandem mass spectrometry (nano-LC-ESI-MS/MS). The protein component of hAH was also analyzed by antibody-based protein arrays, and selected proteins were quantified. Results. A total of 676 proteins were identified in hAH. Of the 355 proteins identified by nano-LC-ESI-MS/MS, 206 were found in all three groups. Most of the proteins identified by nano-LC-ESI-MS/MS had catalytic, enzymatic, and structural properties. Using antibody-based protein arrays, 328 cytokines, chemokines, and receptors were identified. Most of the quantified proteins had concentrations that ranged between 0.1 and 2.5 ng/mL. Ten proteins were identified by both nano-LC-ESI-MS/MS and antibody protein arrays. Conclusions. Proteomic analysis of hAH identified 676 nonredundant proteins. More than 80% of these proteins are novel identifications. The elucidation of the aqueous proteome will establish a foundation for protein function analysis and identification of differentially expressed markers associated with diseases of the anterior segment. PMID:20463327

  17. Actinide recovery using aqueous biphasic extraction: Initial developmental studies

    SciTech Connect

    Chaiko, D.J.; Mensah-Biney, R.; Mertz, C.J.; Rollins, A.N.

    1992-08-01

    Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less.

  18. Dynamics of Aqueous Foam Drops

    NASA Technical Reports Server (NTRS)

    Akhatov, Iskander; McDaniel, J. Gregory; Holt, R. Glynn

    2001-01-01

    We develop a model for the nonlinear oscillations of spherical drops composed of aqueous foam. Beginning with a simple mixture law, and utilizing a mass-conserving bubble-in-cell scheme, we obtain a Rayleigh-Plesset-like equation for the dynamics of bubbles in a foam mixture. The dispersion relation for sound waves in a bubbly liquid is then coupled with a normal modes expansion to derive expressions for the frequencies of eigenmodal oscillations. These eigenmodal (breathing plus higher-order shape modes) frequencies are elicited as a function of the void fraction of the foam. A Mathieu-like equation is obtained for the dynamics of the higher-order shape modes and their parametric coupling to the breathing mode. The proposed model is used to explain recently obtained experimental data.

  19. ENGINEERING BULLETIN: AIR STRIPPING OF AQUEOUS SOLUTIONS

    EPA Science Inventory

    Air striding is a means to transfer contaminants from aqueous solutions to air. ontaminants are not destroyed by air stripping but are physically separated from the aqueous solutions. ontaminant vapors are transferred into the air stream and, if necessary, can be treated by incin...

  20. 27 CFR 21.96 - Ammonia, aqueous.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent...

  1. 27 CFR 21.96 - Ammonia, aqueous.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent...

  2. 27 CFR 21.96 - Ammonia, aqueous.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent...

  3. 27 CFR 21.96 - Ammonia, aqueous.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent...

  4. SEPARATION OF RUTHENIUM FROM AQUEOUS SOLUTIONS

    DOEpatents

    Beederman, M.; Vogler, S.; Hyman, H.H.

    1959-07-14

    The separation of rathenium from a rathenium containing aqueous solution is described. The separation is accomplished by adding sodium nitrite, silver nitrate and ozone to the ruthenium containing aqueous solution to form ruthenium tetroxide and ihen volatilizing off the ruthenium tetroxide.

  5. REMOVAL OF CHLORIDE FROM AQUEOUS SOLUTIONS

    DOEpatents

    Schulz, W.W.

    1959-08-01

    The removal of chlorides from aqueons solutions is described. The process involves contacting the aqueous chloride containing solution with a benzene solution about 0.005 M in phenyl mercuric acetate whereby the chloride anions are taken up by the organic phase and separating the organic phase from the aqueous solutions.

  6. Development of tropine-salt aqueous two-phase systems and removal of hydrophilic ionic liquids from aqueous solution.

    PubMed

    Wu, Haoran; Yao, Shun; Qian, Guofei; Song, Hang

    2016-08-26

    A novel aqueous two-phase systems (ATPS) composed of a small molecule organic compound tropine and an organic or inorganic salt aqueous solution has been developed for the first time. The phase behavior of tropine-salt ATPS was systemically investigated and the phase equilibrium data were measured in different temperatures and concentrations and correlated by the Merchuk equation with satisfactory results. The detection of the conductivity and particle size proved the formation of micelle in the process of forming tropine-salt ATPS. The separation application of the ATPS was assessed with the removal of hydrophilic benzothiazolium-based ionic liquids (ILs) from aqueous solution. The result showed that ILs were effectively extracted into the top tropine-rich phase. Finally, ILs in the top tropine-rich phase were further separated by the means of adsorption-desorption with DM301 macroporous resin and ethanol. The method of novel tropine-salt ATPS combined with adsorption-desorption is demonstrated a promising alternative thought and approach for the removal or recovery of hydrophilic compounds from aqueous media and also could provide a potential application for bio-separation. PMID:27485150

  7. Mukaiyama Aldol Reactions in Aqueous Media

    PubMed Central

    Kitanosono, Taku; Kobayashi, Shū

    2013-01-01

    Mukaiyama aldol reactions in aqueous media have been surveyed. While the original Mukaiyama aldol reactions entailed stoichiometric use of Lewis acids in organic solvents under strictly anhydrous conditions, Mukaiyama aldol reactions in aqueous media are not only suitable for green sustainable chemistry but are found to produce singular phenomena. These findings led to the discovery of a series of water-compatible Lewis acids such as lanthanide triflates in 1991. Our understanding on these beneficial effects in the presence of water will be deepened through the brilliant examples collected in this review. 1 Introduction 2 Rate Enhancement by Water in the Mukaiyama Aldol Reaction 3 Lewis Acid Catalysis in Aqueous or Organic Solvents 3.1 Water-Compatible Lewis Acids 4 Lewis-Base Catalysis in Aqueous or Organic Solvents 5 The Mukaiyama Aldol Reactions in 100% Water 6 Asymmetric Catalysts in Aqueous Media and Water 7 Conclusions and Perspective PMID:24971045

  8. Advanced Aqueous Separation Systems for Actinide Partitioning

    SciTech Connect

    Nash, Ken; Martin, Leigh; Lumetta, Gregg

    2015-04-02

    necessary for commercial fuel processing supporting transmutation of transplutonium elements. This research project continued basic themes investigated by this research group during the past decade. In the Fuel Cycle Research and Development program at DOE, the current favorite process for accomplishing the separation of trivalent actinides from fission product lanthanides is the TALSPEAK process. TALSPEAK is a solvent extraction method (developed at Oak Ridge National Lab in the 1960s) based on the combination of a cation exchanging extractant (e.g., HDEHP), an actinide-selective aminopolycarboxylate complexing agent (e.g., DTPA), and a carboxylic acid buffer to control pH in the range of 3-4. Considerable effort has been expended in this research group during the past 8 years to elaborate the details of TALSPEAK in the interest of developing improved approaches to the operation of TALSPEAK-like systems. In this project we focused on defining aggregation phenomena in conventional TALSPEAK separations, on supporting the development of Advanced TALSPEAK processes, on profiling the aqueous complexation kinetics of lanthanides in TALSPEAK relevant aqueous media, on the design of new diglycolamide and N-donor extractants, and on characterizing cation-cation complexes of pentavalent actinides.

  9. Rheological Properties of Aqueous Nanometric Alumina Suspensions

    SciTech Connect

    Li, Chuanping

    2004-01-01

    Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the 17O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles

  10. Aqueous Angiography–Mediated Guidance of Trabecular Bypass Improves Angiographic Outflow in Human Enucleated Eyes

    PubMed Central

    Huang, Alex S.; Saraswathy, Sindhu; Dastiridou, Anna; Begian, Alan; Mohindroo, Chirayu; Tan, James C. H.; Francis, Brian A.; Hinton, David R.; Weinreb, Robert N.

    2016-01-01

    Purpose To assess the ability of trabecular micro-bypass stents to improve aqueous humor outflow (AHO) in regions initially devoid of AHO as assessed by aqueous angiography. Methods Enucleated human eyes (14 total from 7 males and 3 females [ages 52–84]) were obtained from an eye bank within 48 hours of death. Eyes were oriented by inferior oblique insertion, and aqueous angiography was performed with indocyanine green (ICG; 0.4%) or fluorescein (2.5%) at 10 mm Hg. With an angiographer, infrared and fluorescent images were acquired. Concurrent anterior segment optical coherence tomography (OCT) was performed, and fixable fluorescent dextrans were introduced into the eye for histologic analysis of angiographically positive and negative areas. Experimentally, some eyes (n = 11) first received ICG aqueous angiography to determine angiographic patterns. These eyes then underwent trabecular micro-bypass sham or stent placement in regions initially devoid of angiographic signal. This was followed by fluorescein aqueous angiography to query the effects. Results Aqueous angiography in human eyes yielded high-quality images with segmental patterns. Distally, angiographically positive but not negative areas demonstrated intrascleral lumens on OCT images. Aqueous angiography with fluorescent dextrans led to their trapping in AHO pathways. Trabecular bypass but not sham in regions initially devoid of ICG aqueous angiography led to increased aqueous angiography as assessed by fluorescein (P = 0.043). Conclusions Using sequential aqueous angiography in an enucleated human eye model system, regions initially without angiographic flow or signal could be recruited for AHO using a trabecular bypass stent. PMID:27588614

  11. Converting sugars to sugar alcohols by aqueous phase catalytic hydrogenation

    DOEpatents

    Elliott, Douglas C.; Werpy, Todd A.; Wang, Yong; Frye, Jr., John G.

    2003-05-27

    The present invention provides a method of converting sugars to their corresponding sugar alcohols by catalytic hydrogenation in the aqueous phase. It has been found that surprisingly superior results can be obtained by utilizing a relatively low temperature (less than 120.degree. C.), selected hydrogenation conditions, and a hydrothermally stable catalyst. These results include excellent sugar conversion to the desired sugar alcohol, in combination with long life under hydrothermal conditions.

  12. Adsorption analysis of ammonia in an aqueous solution

    SciTech Connect

    Arman, B.; Panchal, C.B.

    1993-08-01

    An analysis is carried out to determine the effects of the diffusional resistance on the rate of the adsorption of ammonia in an aqueous solution. A performance prediction model is developed to calculate the local rate of heat and mass transfer, including physical and thermodynamic property calculations of the mixture. An algorithm is developed for calculating the interfacial conditions. The local heat- and mass-transfer calculation is then incorporated into the performance prediction method for adsorption for a given geometry.

  13. Microwave-Assisted Hydrogenation of Codeine in Aqueous Media

    PubMed Central

    Taktak, F.; Bulduk, I.

    2012-01-01

    An efficient one-pot microwave-assisted hydrogenation of codeine was achieved in aqueous solution. This technique is simple, fast, environmentally friendly, and highly efficient. Structure of produced dihydrocodeine was approved by using FT-IR, 1H NMR, 13C NMR, EIMS, and elemental analysis technique. Its purity analysis was performed by using HPLC and assay analysis was performed by using potentiometric titration methods. PMID:24052836

  14. Fiber-Optic Chemiluminescent Biosensors for Monitoring Aqueous Alcohols and Other Water Quality Parameters

    NASA Technical Reports Server (NTRS)

    Verostko, Charles E. (Inventor); Atwater, James E. (Inventor); Akse, James R. (Inventor); DeHart, Jeffrey L. (Inventor); Wheeler, Richard R. (Inventor)

    1998-01-01

    A "reagentless" chemiluminescent biosensor and method for the determination of hydrogen peroxide, ethanol and D-glucose in water is disclosed. An aqueous stream is basified by passing it through a solid phase base bed. Luminol is then dissolved in the basified effluent at a controlled rate. Oxidation of the luminol is catalyzed by the target chemical to produce emitted light. The intensity of the emitted light is detected as a measure of the target chemical concentration in the aqueous stream. The emitted light can be transmitted by a fiber optic bundle to a remote location from the aqueous stream for a remote reading of the target chemical concentration.

  15. Single-step colloidal processing of stable aqueous dispersions of ferroelectric nanoparticles for biomedical imaging

    NASA Astrophysics Data System (ADS)

    Zribi, Olena; Garbovskiy, Yuriy; Glushchenko, Anatoliy

    2014-12-01

    The biomedical applications of ferroelectric nanoparticles rely on the production of stable aqueous colloids. We report an implementation of the high energy ball milling method to produce and disperse ultrafine BaTiO3 nanoparticles in an aqueous media in a single step. This technique is low-cost, environmentally friendly and has the capability to control nanoparticle size and functionality with milling parameters. As a result, ultrafine nanoparticles with sizes as small as 6 nm can be produced. These nanoparticles maintain ferroelectricity and can be used as second harmonic generating nanoprobes for biomedical imaging. This technique can be generalized to produce aqueous nanoparticle colloids of other imaging materials.

  16. Formation and disappearance of superoxide radicals in aqueous solutions. [79 references

    SciTech Connect

    Allen, A O; Bielski, B H.J.

    1980-01-01

    A literature review of superoxide radicals in aqueous solutions is presented covering the following: history; methods of formation of aqueous HO/sub 2//HO/sub 2//sup -/ by radiolysis and photolysis, electrolysis, mixing nonaqueous solutions into water, chemical reactions, enzymatic generation of O/sub 2//sup -/, and photosensitization; and properties of HO/sub 2//O/sub 2//sup -/ in aqueous solution, which cover spontaneous dismutation rates, pk and absorption spectra, catalyzed dismutation, thermodynamics and the so-called Haber-Weiss Reaction.

  17. Studies on the blood-aqueous barrier after argon laser photocoagulation of the iris

    SciTech Connect

    Sanders, D.R.; Joondeph, B.; Hutchins, R.; Schwartz, D.; Yeh, T.; Peyman, G.A.

    1983-02-01

    Breakdown and re-establishment of the blood-aqueous barrier (BAB) was studied following laser irradiation to the rabbit iris by quantitating leakage of protein, fluorescein, and fluorescein-labeled dextran (FLD-70, MW 70,000) into the aqueous humor. Breakdown of the BAB was more prolonged in pigmented than albino animals, possibly due to the increased laser energy absorbed by the pigmented iris. Fluorophotometry appeared to be a more sensitive method for evaluating BAB breakdown than aqueous protein measurements, and small molecule leakage (fluorescein) appeared to be more sensitive than macromolecule leakage (FLD-70). The noninvasive method of evaluating the BAB proved equally as effective as measuring aqueous protein content in assessing the sensitivity of laser-induced trauma to the ameliorating effect of the nonsteroidal anti-inflammatory agent indomethacin.

  18. Aqueous CO{sup 2} vs. aqueous extraction of soils as a preparative procedure for acute toxicity testing

    SciTech Connect

    Yates, G.W.; Burks, S.L.

    1994-12-31

    This study was to determine if contaminated soils extracted with supercritical CO{sup 2} (SFE) would yield different results from soils extracted with an aqueous media. Soil samples from an abandoned oil refinery were subjected to aqueous and SFE extraction. Uncontaminated control sites were compared with contaminated sites. Each extract was analyzed for 48 hour acute Ceriodaphnia LC50s and Microtox{reg_sign} EC50s. Comparisons were then made between the aqueous extracts and the SFE extracts. An additional study was made with HPLC chromatographs of the SFE contaminated site extracts to determine if there was a correlation between LC50 results and peak area of different sections of the chromatograph. The 48 hour Ceriodaphnia LC50 of one contaminated site showed a significant increase in toxicity with the supercritical extract compared to the aqueous extract. All contaminated sites gave toxic responses with the supercritical procedure. The Microtox{reg_sign} assay showed a toxic response with 2 of the 3 contaminated sites for both aqueous and SFE extracts. Results indicate that the Ceriodaphnia assays were more sensitive than Microtox{reg_sign} to contaminants found in the refinery soil. SFE controls did not show adverse effects with the Ceriodaphnia, but did have a slight effect with Microtox{reg_sign}. The best correlation (r{sup 2} > 0.90) between the Ceriodaphnia LC50s and the peak areas of the chromatographs was obtained for sections with an estimated log K{sub ow} of 1 to 5. SFE extraction provided a fast, efficient and inexpensive method of collecting and testing moderately non-polar to strongly non-polar organic contaminants from contaminated soils.

  19. Mars Aqueous Chemistry Experiment (MACE)

    NASA Technical Reports Server (NTRS)

    Benton, Clark C. (Editor)

    1995-01-01

    The concept of an aqueous-based chemical analyzer for Martian surface materials has been demonstrated to be feasible. During the processes of analysis, design, breadboarding, and most importantly, testing, it has become quite apparent that there are many challenges in implementing such a system. Nonetheless, excellent progress has been made and a number of problems which arose have been solved. The ability to conduct this work under a development environment which is separate and which precedes the project-level development has allowed us to find solutions to these implementation realities at low cost. If the instrument had been selected for a mission without this laboratory pre-project work, the costs of implementation would be much higher. In the four areas covered in Sections D, E, F, and G of this Final Report, outstanding progress has been made. There still remains the task of flight-qualifying certain of the components. This is traditionally done under the aegis of a Flight Project, but just as the concept development can be done at much lower cost when kept small and focused, so could the qualification program of critical parts benefit. We recommend, therefore, that NASA consider means of such qualifications and brass-boarding, in advance of final flight development. This is a generic recommendation, but hardware such as the Mars aqueous chemistry experiment (MACE) and other similarly-new concepts are particularly applicable. MACE now has wide versatility, in being able to reliably dispense both liquids and solids as chemical reagents to an entire suite of samples. The hardware and the experiment is much simpler than was developed for the Viking Biology instrument, yet can accomplish all the inorganic chemical measurements that the Viking desing was capable of. In addition, it is much more flexible and versatile to new experiment protocols (and reagents) than the Viking design ever could have been. MACE opens up the opportunity for many different scientific

  20. Biodegradation and toxicity of a crude oil/aqueous system in the presence of a biosurfactant

    SciTech Connect

    Page, C.A.; Bonner, J.S.; Kanga, S.A.

    1995-12-31

    Biodegradation studies were performed on aqueous solutions containing surfactants. The solutions were analyzed for microbial growth and depletion of polycyclic aromatic hydrocarbons (PAHs). The toxicity of the mixture was calculated using linear regression methods. Detailed results are presented, which indicate that the biosurfactants increased the aqueous solubilities for petroluem PAHs. The increased toxicities of these solutions support this conclusion. Preliminary results indicate that degradation rates are also increased by the presence of biosurfactants.

  1. Picogram sensing of trinitrophenol in aqueous medium through a water stable nanoscale coordination polymer.

    PubMed

    Asha, K S; Vaisakhan, G S; Mandal, Sukhendu

    2016-06-01

    A water stable nanoscale coordination polymer (CP) can detect trinitrophenol (TNP) in an aqueous medium at a record-picogram level (∼1.66 pg cm(-2)) with a detection limit of 1.66 ppb. This is a simple and low-cost method for the detection of TNP in aqueous media in contact mode, taking advantage of the unique structural arrangement of the as-synthesized CP and the associated photophysical properties.

  2. Aqueous processing in materials science and engineering

    NASA Astrophysics Data System (ADS)

    Mooiman, Michael B.; Sole, Kathryn C.

    1994-06-01

    Reviews of aqueous processing in JOM have traditionally focused on hydrometallurgical process routes. This article, however, addresses the application of aqueous processing in materials engineering and presents some promising developments that employ aqueous-based routes for the manufacture of high-tech components and specialty products. Such applications include producing metallic and ceramic powders; etching; surface modification by electroplating and electroless plating; manufacturing jewelry and intricate components by electroforming; and producing advanced ceramics, composites, and nanophase materials by sol-gel and biomimetic processing.

  3. Hydrophobic effect at aqueous interfaces

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew

    2005-01-01

    Conceptual basis for hydrophobic effects in bulk water and at aqueous interfaces have similar conceptual basis but often manifests itself differently. Using a wide range of computer simulations as the basis, I will review different forms of hydrophobic effects at a variety of interfaces starting from simple liquid-vapor and water-oil interfaces and progressing to water-membrane interfaces. I will start with discussing how water is organized at different interfaces, stressing both similarities and differences. The main thread is that, as in the bulk liquid, hydrophobic effects have profound influence on conformational equilibria and organization of both small molecules and macromolecules, but the result of this influence is quite different. Specifically, it will be shown that many small, but not necessarily amphiphilic molecules tend to accumulate at the interface and, and this tendency will be explained. Furthermore, I will show that many short peptides that are disordered in water spontaneously fold into well-defined structures in the interfacial environment. Biological implications of this self-organizing effect will be discussed.

  4. Purification of aqueous cellulose ethers

    SciTech Connect

    Bartscherer, K.A.; de Pablo, J.J.; Bonnin, M.C.; Prausnitz, J.M.

    1990-07-01

    Manufacture of cellulose ethers usually involves high amounts of salt by-products. For application of the product, salt must be removed. In this work, we have studied the injection of high-pressure CO{sub 2} into an aqueous polymer-salt solution; we find that upon addition of isopropanol in addition to CO{sub 2}, the solution separates into two phases. One phase is rich in polymer and water, and the other phase contains mostly isopropanol, water and CO{sub 2}. The salt distributes between the two phases, thereby offering interesting possibilities for development of a new purification process for water-soluble polymers. This work presents experimental phase-equilibrium data for hydroxyethyl cellulose and sodium carboxymethyl cellulose with sodium acetate and potassium sulfate, respectively, in the region 40{degree}C and 30 to 80 bar. Based on these data, we suggest a process for the manufacture and purification of water-soluble cellulose ethers. 15 refs., 14 figs., 9 tabs.

  5. Aqueous Alteration of Enstatite Chondrites

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Ziegler, K.; Weisberg, M. K.; Gounelle, M.; Berger, E. L.; Le, L.; Ivanov, A.

    2014-01-01

    The Kaidun meteorite is different from all other meteorites [1], consisting largely of a mixture of “incompatible” types of meteoritic material – carbonaceous and enstatite chondrites, i.e. corre-sponding to the most oxidized and the most reduced samples of meteorite materials, including CI1, CM1-2, CV3, EH3-5, and EL3. In addition to these, minor amounts of ordinary and R chondrites are present. In addition, approximately half of the Kaidun lithologies are new materials not known as separate meteorites. Among these are aqueously altered enstatite chondrites [1], which are of considerable interest because they testify that not all reduced asteroids escaped late-stage oxidation, and hydrolysis, and also because hydrated poorly crystalline Si-Fe phase, which in turn is re-placed by serpentine (Figs 3-5). In the end the only indication of the original presence of metal is the re-sidual carbides. In other enstatite chondrite lithogies (of uncertain type) original silicates and metal have been thoroughly replaced by an assemblage of authi-genic plagioclase laths, calcite boxwork, and occasion-al residual grains of silica, Cr-rich troilite, ilmenite, and rare sulfides including heideite (Fig. 6). Fe and S have been largely leached from the rock (Fig. 4). Again the accessory phases are the first clue to the original character of the rock, which can be verified by O isotopes. It is fortunate that Kaidun displays every step of the alteration process.

  6. Densities of aqueous blended amines

    SciTech Connect

    Hsu, C.H.; Li, M.H.

    1997-05-01

    Solutions of alkanolamines are an industrially important class of compounds used in the natural gas and synthetic ammonia industries and petroleum chemical plants for the removal of CO{sub 2} and H{sub 2}S from gas streams. The densities of aqueous mixtures of diethanolamine (DEA) + N-methyldiethanolamine (MDEA) + water, DEA + 2-amino-2-methyl-1-propanol (AMP) + water, and monoethanolamine (MEA) + 2-piperidineethanol (2-PE) + water were measured from 30 C to 80 C. A Redlich-Kister equation of the excess volume was applied to represent the density. Based on the available density data for five ternary systems: MEA + MDEA + H{sub 2}O, MEA + AMP + H{sub 2}O, DEA + MDEA + H{sub 2}O, DEA + AMP + H{sub 2}O, and MEA + 2-PE + H{sub 2}O, a generalized set of binary parameters were determined. The density calculations show quite satisfactory results. The overall average absolute percent deviation is about 0.04% for a total of 686 data points.

  7. Viscosities of aqueous blended amines

    SciTech Connect

    Hsu, C.H.; Li, M.H.

    1997-07-01

    Solutions of alkanolamines are an industrially important class of compounds used in the natural gas, oil refineries, petroleum chemical plants, and synthetic ammonia industries for the removal of acidic components like CO{sub 2} and H{sub 2}S from gas streams. The viscosities of aqueous mixtures of diethanolamine (DEA) + N-methyldiethanolamine (MDEA), DEA + 2-amino-2-methyl-1-propanol (AMP), and monoethanolamine (MEA) + 2-piperidineethanol (2-PE) were measured from 30 C to 80 C. A Redlich-Kister equation for the viscosity deviation was applied to represent the viscosity. On the basis of the available viscosity data for five ternary systems, MEA + MDEA + H{sub 2}O, MEA + AMP + H{sub 2}O, DEA + MDEA + H{sub 2}O, DEA + AMP + H{sub 2}O, and MEA + 2-PE + H{sub 2}O, a generalized set of binary parameters were determined. For the viscosity calculation of the systems tested, the overall average absolute percent deviation is about 1.0% for a total of 499 data points.

  8. Chromatographic determination of aqueous dissociation constants of some water-insoluble nonsteroidal antiinflammatory drugs.

    PubMed

    Oumada, Fadoua Z; Ràfols, Clara; Rosés, Martí; Bosch, Elisabeth

    2002-04-01

    The purpose of this work is to propose a new, useful, and easy chromatographic method to determine accurately the aqueous dissociation constant of drugs sparingly soluble in water. The method uses the rigorous intersolvental pH scale, (w)(s)pH, i.e., the pH measurements are made in the mobile phase after mixing the aqueous buffer with methanol by a combined glass electrode previously standardised with common aqueous buffers. The measured pK allows the determination of the drug's pK(a) in the mobile phase, (w)(s)pK(a), which can be easily converted in the aqueous pK(a), (w)(w)pK(a), by means of previously established equations. A series of nonsteroidal carboxylic acids with antiinflammatory properties were selected to test the method because their aqueous pK(a) values, (w)(w)pK(a), had been previously evaluated from different approaches that gave consistent results. The comparison of the aqueous pK(a) values obtained by means of the proposed procedure with those of literature allows the accurate evaluation of this new methodology. The results obtained show very good precision and accuracy.

  9. X-ray absorption microscopy of aqueous samples

    NASA Astrophysics Data System (ADS)

    Frazer, Brad; Gilbert, Benjamin; De Stasio, Gelsomina

    2002-03-01

    X-ray photoelectron emission microscopy (X-PEEM) is used for numerous applications in surface microchemical analysis of material science and biological specimens. We have reconfigured the MEPHISTO X-PEEM instrument that is installed at the University of Wisconsin Synchrotron Radiation Center to measure true x-ray transmission spectra by converting transmitted photons to photoelectrons via a thin photocathode layer of gold. We have also developed a method by which to introduce aqueous samples into ultrahigh vacuum. Hence x-ray spectroscopy can be performed on biologically relevant elements (such as K, Ca, etc.) in a physiological environment, i.e., in solution. More important, when coupled with X-PEEM imaging this technique may offer the unique and exciting possibility of studying living cells. We present initial x-ray absorption spectra of solutions of aqueous ionic and chelated Ca, with the aim of distinguishing bound and free ionic calcium in vivo.

  10. Enhanced aqueous solubilization of tetrachloroethylene by a rhamnolipid biosurfactant.

    PubMed

    Clifford, Joseph S; Ioannidis, Marios A; Legge, Raymond L

    2007-01-15

    A rhamnolipid biosurfactant produced by Pseudomonas aeruginosa ATCC 9027 was isolated, purified and characterized in terms of its ability to mobilize and solubilize tetrachloroethylene (PCE) for potential use in surfactant-enhanced aquifer remediation (SEAR) applications. Using a drop volume method, the PCE-biosurfactant steady-state interfacial tension was determined and found to be ca. 10 mN/m which is not low enough to cause significant PCE nonaqueous phase liquid (NAPL) mobilization. It was observed that the biosurfactant partitioned significantly into PCE at aqueous concentrations higher than the critical micelle concentration (CMC). After accounting for rhamnolipid partitioning into the PCE phase, a weight solubilization ratio (WSR) of 1.2 g(PCE)/g(rhamnolipid) was determined and through this mechanism the biosurfactant significantly improved the apparent aqueous solubility of PCE.

  11. Removal of phenol from aqueous solution using carbonized Terminalia chebula-activated carbon: process parametric optimization using conventional method and Taguchi's experimental design, adsorption kinetic, equilibrium and thermodynamic study

    NASA Astrophysics Data System (ADS)

    Khare, Prateek; Kumar, Arvind

    2012-12-01

    In the present paper, the phenol removal from wastewater was investigated using agri-based adsorbent: Terminalia chebula-activated carbon (TCAC) produced by carbonization of Terminalia chebula (TC) in air-controlled atmosphere at 600 °C for 4 h. The surface area of TCAC was measured as 364 m2/g using BET method. The surface characteristic of TCAC was analyzed based on the value of point of zero charge. The effect of parameters such as TCAC dosage, pH, initial concentration of phenol, time of contact and temperature on the sorption of phenol by TCAC was investigated using conventional method and Taguchi experimental design. The total adsorption capacity of phenol was obtained as 36.77 mg/g using Langmuir model at the temperature of 30 °C at pH = 5.5. The maximum removal of phenol (294.86 mg/g) was obtained using Taguchi's method. The equilibrium study of phenol on TCAC showed that experimental data fitted well to R-P model. The results also showed that kinetic data were followed more closely the pseudo-first-order model. The results of thermodynamic study showed that the adsorption of phenol on TCAC was spontaneous and an exothermic in nature.

  12. ELECTROCHEMICAL DECHLORINATIONOF 2-CHLOROBIPHENYL IN AQUEOUS SOLUTION

    EPA Science Inventory

    This paper presents electrochemical dechlorination of 2-chlorobiphenyl (2-CI BP) in aqueous environment using palladium modified granular graphite electrodes. 2-CI BP, the PCB congener that requires the highest reduction potential, was effectively dechlorinated in electrochemical...

  13. Aqueous humor cytokine profiling in patients with wet AMD

    PubMed Central

    Liu, Fang; Ding, Xiaoyan; Yang, Yu; Li, Jiaqing; Tang, Miao; Yuan, Miner; Hu, Andina; Zhan, Zongyi; Li, Zijing

    2016-01-01

    Purpose To investigate the chemokine expression profiles in the aqueous humor of wet age-related macular degeneration (wet AMD) patients and to correlate their levels with clinical findings. Methods Undiluted aqueous humor samples (100–200 μl) were obtained from 16 wet AMD eyes and 12 control eyes. Forty chemokines were measured using a multiplex method. A 6×6 mm area of the macular region centered on the fovea was examined using spectral domain optical coherence tomography (SD-OCT). Results The detection rates were 50% or more for 15 chemokines. Compared with the control group, the aqueous humor in wet AMD patients showed a significantly higher expression of CXCL10 (p=0.004), CCL14 (p=0.002), CXCL16 (p=0.013), CXCL7 (p=0.033), and CCL22 (p=0.037), while growth-related oncogene (GRO) was significantly decreased in the wet AMD patients (p=0.001). When compared with treatment-naïve patients, the recurrent group had significant upregulation of CXCL10 (p=0.012) and CCL22 (p=0.002). CXCL16 was positively correlated with lesion size, and CCL22 was higher in patients whose OCT images showed intraretinal fluid (IRF) or hyperreflective foci (HF). Conclusions Elevated levels of inflammation-related chemokines, including CXCL10, CCL14, CXCL16, CXCL7, and CCL22, in the aqueous humor of AMD patients may suggest a pathogenic role for inflammation. CXCL10 and CCL22 were more elevated in eyes with recurrent wet AMD than in treatment-naïve eyes. CXCL16 was positively correlated with lesion size. The increase in CCL22 was correlated with the presence of IRF or HF. These data may be of interest in the search for biomarkers associated with wet AMD and may potentially indicate different treatment strategies. PMID:27122966

  14. Precipitation of neptunium dioxide from aqueous solution

    SciTech Connect

    Roberts, K E

    1999-12-01

    Tens of thousands of metric tons of highly radioactive, nuclear waste have been generated in the US. Currently, there is no treatment or disposal facility for these wastes. Of the radioactive elements in high-level nuclear waste, neptunium (Np) is of particular concern because it has a long half-life and may potentially be very mobile in groundwaters associated with a proposed underground disposal site at Yucca Mountain, Nevada. Aqueous Np concentrations observed in previous, short-term solubility experiments led to calculated potential doses exceeding proposed long-term regulatory limits. However, thermodynamic data for Np at 25 C showed that these observed aqueous Np concentrations were supersaturated with respect to crystalline NpO{sub 2}. It was hypothesized that NpO{sub 2} is the thermodynamically stable solid phase in aqueous solution, but it is slow to form in an aqueous solution of NpO{sub 2}{sup +} on the time scale of previous experiments. The precipitation of NpO{sub 2} would provide significantly lower aqueous Np concentrations leading to calculated doses below proposed regulatory limits. To test this hypothesis, solubility experiments were performed at elevated temperature to accelerate any slow precipitation kinetics. Ionic NpO{sub 2}{sup +} (aq) was introduced into very dilute aqueous solutions of NaCl with initial pH values ranging from 6 to 10. The reaction vessels were placed in an oven and allowed to react at 200 C until steady-state aqueous Np concentrations were observed. In all cases, aqueous Np concentrations decreased significantly from the initial value of 10{sup {minus}4} M. The solids that formed were analyzed by x-ray powder diffraction, x-ray absorption spectroscopy, and scanning electron microscopy. The solids were determined to be high-purity crystals of NpO{sub 2}. This is the first time that crystalline NpO{sub 2} has been observed to precipitate from NpO{sub 2}{sup +}(aq) in near-neutral aqueous solutions. The results obtained

  15. Aqueous phase processing of secondary organic aerosols

    NASA Astrophysics Data System (ADS)

    Liu, Yao; Tritscher, T.; Praplan, A. P.; Decarlo, P. F.; Temime-Roussel, B.; Quivet, E.; Marchand, N.; Dommen, J.; Baltensperger, U.; Monod, A.

    2011-07-01

    The aging of secondary organic aerosol (SOA) by photooxidation in the aqueous phase was experimentally investigated. To simulate multiphase processes, the following experiments were sequentially performed in a smog chamber and in an aqueous phase photoreactor: (1) Gas-phase photooxidation of three different volatile organic compounds (VOC): isoprene, α-pinene, and 1,3,5-trimethylbenzene (TMB) in the presence of NOx, leading to the formation of SOA which was subjected to on-line physical and chemical analysis; (2) particle-to-liquid transfer of water soluble species of SOA using filter sampling and aqueous extraction; (3) aqueous-phase photooxidation of the obtained water extracts; and (4) nebulization of the solutions for a repetition of the on-line characterization. SOA concentrations in the chamber measured with a scanning mobility particle sizer (SMPS) were higher than 200 μg m-3, as the experiments were conducted under high initial concentrations of volatile organic compounds (VOC) and NOx. The aging of SOA through aqueous phase processing was investigated by measuring the physical and chemical properties of the particles online before and after processing using a high resolution time-of-flight aerosol mass spectrometer (AMS) and a hygroscopicity tandem differential mobility analyzer (H-TDMA). It was shown that, after aqueous phase processing, the particles were significantly more hygroscopic, and contained more fragmentation ions at m/z = 44 and less ions at m/z = 43, thus showing a significant impact on SOA aging for the three different precursors. Additionally, the particles were analyzed with a thermal desorption atmospheric pressure ionization aerosol mass spectrometer (TD-API-AMS). Comparing the smog chamber SOA composition and non processed nebulized aqueous extracts with this technique revealed that sampling, extraction and/or nebulization did not significantly impact the chemical composition of SOA formed from isoprene and α-pinene, whereas it

  16. RECOVERY OF TETRAVALENT CATIONS FROM AQUEOUS SOLUTIONS

    DOEpatents

    Moore, R.L.

    1958-05-01

    The recovery of plutonium, zirconium, and tetravalent cerium values from aqueous solutions is described. It consists of adding an alkyl phosphate to a nnineral acid aqueous solution containing the metal to be recovered, whereby a precipitate forms with the tetravalent values, and separating the precipitate from the solution. All alkyl phosphates, if water-soluble, are suitable for the process; however, monobutyl phosphate has been found best.

  17. Aqueous foam toxicology evaluation and hazard review

    SciTech Connect

    Archuleta, M.M.

    1995-10-01

    Aqueous foams are aggregates of bubbles mechanically generated by passing air or other gases through a net, screen, or other porous medium that is wetted by an aqueous solution of surface-active foaming agents (surfactants). Aqueous foams are important in modem fire-fighting technology, as well as for military uses for area denial and riot or crowd control. An aqueous foam is currently being developed and evaluated by Sandia National Laboratories (SNL) as a Less-Than-Lethal Weapon for the National Institute of Justice (NIJ). The purpose of this study is to evaluate the toxicity of the aqueous foam developed for the NIJ and to determine whether there are any significant adverse health effects associated with completely immersing individuals without protective equipment in the foam. The toxicity of the aqueous foam formulation developed for NIJ is determined by evaluating the toxicity of the individual components of the foam. The foam is made from a 2--5% solution of Steol CA-330 surfactant in water generated at expansion ratios ranging from 500:1 to 1000:1. SteoI CA-330 is a 35% ammonium laureth sulfate in water and is produced by Stepan Chemical Company and containing trace amounts (<0.1%) of 1,4-dioxane. The results of this study indicate that Steol CA-330 is a non-toxic, mildly irritating, surfactant that is used extensively in the cosmetics industry for hair care and bath products. Inhalation or dermal exposure to this material in aqueous foam is not expected to produce significant irritation or systemic toxicity to exposed individuals, even after prolonged exposure. The amount of 1,4-dioxane in the surfactant, and subsequently in the foam, is negligible and therefore, the toxicity associated with dioxane exposure is not significant. In general, immersion in similar aqueous foams has not resulted in acute, immediately life-threatening effects, or chronic, long-term, non-reversible effects following exposure.

  18. EXTRACTION OF URANYL NITRATE FROM AQUEOUS SOLUTIONS

    DOEpatents

    Furman, N.H.; Mundy, R.J.

    1957-12-10

    An improvement in the process is described for extracting aqueous uranyl nitrate solutions with an organic solvent such as ether. It has been found that the organic phase will extract a larger quantity of uranyl nitrate if the aqueous phase contains in addition to the uranyl nitrate, a quantity of some other soluble nitrate to act as a salting out agent. Mentioned as suitable are the nitrates of lithium, calcium, zinc, bivalent copper, and trivalent iron.

  19. Photochemistry of norharmane in aqueous solution.

    PubMed

    Gonzalez, M Micaela; Salum, M Laura; Gholipour, Yousef; Cabrerizo, Franco M; Erra-Balsells, Rosa

    2009-08-01

    The photochemistry of norharmane (9H-pyrido[3,4-b]indole) in acidic (pH 5.0+/-0.1) and alkaline (pH 10.0+/-0.1) aqueous solutions was studied. The photochemical reactions were monitored by TLC, UV/VIS absorption spectroscopy, high-performance liquid chromatography (HPLC), electronic ionization-mass spectrometry (EI-MS), UV-laser desorption/ionization-time of flight-mass spectrometry (UV-LDI-TOF-MS) and an enzymatic method for H2O2 determination. The neutral (nHoN) and the protonated (nHoH+) forms of norharmane irradiated under Ar atmosphere were photostable, but they suffered a photochemical transformation in the presence of O2, yielding as photoproducts norharmane dimers, trimers and tetramers. nHoN shown to be more photostable than nHoH+. The nHoH+ and nHoN consumption quantum yields were 1.82x10(-3) and 0.51x10(-3), respectively, and the mechanisms involved in its photochemistry are discussed. H2O2 and singlet oxygen (1O2) were also detected and quantified in irradiated solutions of norharmane, and their role in the photochemistry of norharmane is discussed.

  20. Fenton chemistry at aqueous interfaces

    PubMed Central

    Enami, Shinichi; Sakamoto, Yosuke; Colussi, Agustín J.

    2014-01-01

    In a fundamental process throughout nature, reduced iron unleashes the oxidative power of hydrogen peroxide into reactive intermediates. However, notwithstanding much work, the mechanism by which Fe2+ catalyzes H2O2 oxidations and the identity of the participating intermediates remain controversial. Here we report the prompt formation of O=FeIVCl3− and chloride-bridged di-iron O=FeIV·Cl·FeIICl4− and O=FeIV·Cl·FeIIICl5− ferryl species, in addition to FeIIICl4−, on the surface of aqueous FeCl2 microjets exposed to gaseous H2O2 or O3 beams for <50 μs. The unambiguous identification of such species in situ via online electrospray mass spectrometry let us investigate their individual dependences on Fe2+, H2O2, O3, and H+ concentrations, and their responses to tert-butanol (an ·OH scavenger) and DMSO (an O-atom acceptor) cosolutes. We found that (i) mass spectra are not affected by excess tert-butanol, i.e., the detected species are primary products whose formation does not involve ·OH radicals, and (ii) the di-iron ferryls, but not O=FeIVCl3−, can be fully quenched by DMSO under present conditions. We infer that interfacial Fe(H2O)n2+ ions react with H2O2 and O3 >103 times faster than Fe(H2O)62+ in bulk water via a process that favors inner-sphere two-electron O-atom over outer-sphere one-electron transfers. The higher reactivity of di-iron ferryls vs. O=FeIVCl3− as O-atom donors implicates the electronic coupling of mixed-valence iron centers in the weakening of the FeIV–O bond in poly-iron ferryl species. PMID:24379389

  1. Aqueous Photochemistry of Glyoxylic Acid.

    PubMed

    Eugene, Alexis J; Xia, Sha-Sha; Guzman, Marcelo I

    2016-06-01

    Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging of photoproducts is studied by UV-visible and fluorescence spectroscopies to reveal that the optical properties are altered by the glyoxal produced. The optical properties display periodicity in the time domain of the UV-visible spectrum of chromophores with absorption enhancement (thermochromism) or loss (photobleaching) during nighttime and daytime cycles, respectively. During irradiation, excited state glyoxylic acid can undergo α-cleavage or participate in hydrogen abstractions. The use of (13)C nuclear magnetic resonance spectroscopy (NMR) analysis shows that glyoxal is an important intermediate produced during direct photolysis. Glyoxal quickly reaches a quasi-steady state as confirmed by UHPLC-MS analysis of its corresponding (E) and (Z) 2,4-dinitrophenylhydrazones. The homolytic cleavage of glyoxylic acid is proposed as a fundamental step for the production of glyoxal. Both carbon oxides, CO2(g) and CO(g) evolving to the gas-phase, are quantified by FTIR spectroscopy. Finally, formic acid, oxalic acid, and tartaric acid photoproducts are identified by ion chromatography (IC) with conductivity and electrospray (ESI) mass spectrometry (MS) detection and (1)H NMR spectroscopy. A reaction mechanism is proposed based on all experimental observations. PMID:27192089

  2. AQUEOUS HOMOGENEOUS REACTORTECHNICAL PANEL REPORT

    SciTech Connect

    Diamond, D.J.; Bajorek, S.; Bakel, A.; Flanagan, G.; Mubayi, V.; Skarda, R.; Staudenmeier, J.; Taiwo, T.; Tonoike, K.; Tripp, C.; Wei, T.; Yarsky, P.

    2010-12-03

    Considerable interest has been expressed for developing a stable U.S. production capacity for medical isotopes and particularly for molybdenum- 99 (99Mo). This is motivated by recent re-ductions in production and supply worldwide. Consistent with U.S. nonproliferation objectives, any new production capability should not use highly enriched uranium fuel or targets. Conse-quently, Aqueous Homogeneous Reactors (AHRs) are under consideration for potential 99Mo production using low-enriched uranium. Although the Nuclear Regulatory Commission (NRC) has guidance to facilitate the licensing process for non-power reactors, that guidance is focused on reactors with fixed, solid fuel and hence, not applicable to an AHR. A panel was convened to study the technical issues associated with normal operation and potential transients and accidents of an AHR that might be designed for isotope production. The panel has produced the requisite AHR licensing guidance for three chapters that exist now for non-power reactor licensing: Reac-tor Description, Reactor Coolant Systems, and Accident Analysis. The guidance is in two parts for each chapter: 1) standard format and content a licensee would use and 2) the standard review plan the NRC staff would use. This guidance takes into account the unique features of an AHR such as the fuel being in solution; the fission product barriers being the vessel and attached systems; the production and release of radiolytic and fission product gases and their impact on operations and their control by a gas management system; and the movement of fuel into and out of the reactor vessel.

  3. Aqueous electrodeposition of Ge monolayers.

    PubMed

    Liang, Xuehai; Kim, Youn-Geun; Gebergziabiher, Daniel K; Stickney, John L

    2010-02-16

    The electrodeposition of germanium on Au(111) in aqueous solutions has been investigated by means of cyclic voltammetry, Auger electron spectroscopy, and in situ scanning tunneling microscopy (STM). The data yield a picture of germanium deposition, which starts with the formation of two well-ordered hydroxide phases, with 1/3 ML and 4/9 ML coverages upon initial reduction of the Ge(IV) species (probably H(2)GeO(3) at pH 4.7). Those structures appear to result from a three-electron reduction to form surface-limited structures with (square root(3) x square root(3))R30 degrees or (3 x 3) unit cells, respectively. Further reduction, probably in a two-electron process from the hydroxide structures, resulted in a germanium hydride structure, again surface-limited, with a coverage of close to 0.8 ML. The hydride structure is very flat, though with the periodic modulation characteristic of a Moiré pattern. Longer deposition times and lower potentials resulted in increased coverage of Ge in some cases, but with apparently limited coverage as a function of pH. The maximum Ge coverage, about 4 ML, was observed using a pH 9.32 deposition solution. At potentials negative of the Moiré pattern, about -850 mV versus Ag/AgCl, a "corruption" of the smooth Moiré pattern occurred. This roughening appears to mark the initial formation of a Au-Ge alloy, accounting for the observation of coverage in excess of that needed to form the Moiré pattern at some pH values.

  4. ASRM process development in aqueous cleaning

    NASA Astrophysics Data System (ADS)

    Swisher, Bill

    1992-12-01

    Viewgraphs are included on process development in aqueous cleaning which is taking place at the Aerojet Advanced Solid Rocket Motor (ASRM) Division under a NASA Marshall Space and Flight Center contract for design, development, test, and evaluation of the ASRM including new production facilities. The ASRM will utilize aqueous cleaning in several manufacturing process steps to clean case segments, nozzle metal components, and igniter closures. ASRM manufacturing process development is underway, including agent selection, agent characterization, subscale process optimization, bonding verification, and scale-up validation. Process parameters are currently being tested for optimization utilizing a Taguci Matrix, including agent concentration, cleaning solution temperature, agitation and immersion time, rinse water amount and temperature, and use/non-use of drying air. Based on results of process development testing to date, several observations are offered: aqueous cleaning appears effective for steels and SermeTel-coated metals in ASRM processing; aqueous cleaning agents may stain and/or attack bare aluminum metals to various extents; aqueous cleaning appears unsuitable for thermal sprayed aluminum-coated steel; aqueous cleaning appears to adequately remove a wide range of contaminants from flat metal surfaces, but supplementary assistance may be needed to remove clumps of tenacious contaminants embedded in holes, etc.; and hot rinse water appears to be beneficial to aid in drying of bare steel and retarding oxidation rate.

  5. ASRM process development in aqueous cleaning

    NASA Technical Reports Server (NTRS)

    Swisher, Bill

    1992-01-01

    Viewgraphs are included on process development in aqueous cleaning which is taking place at the Aerojet Advanced Solid Rocket Motor (ASRM) Division under a NASA Marshall Space and Flight Center contract for design, development, test, and evaluation of the ASRM including new production facilities. The ASRM will utilize aqueous cleaning in several manufacturing process steps to clean case segments, nozzle metal components, and igniter closures. ASRM manufacturing process development is underway, including agent selection, agent characterization, subscale process optimization, bonding verification, and scale-up validation. Process parameters are currently being tested for optimization utilizing a Taguci Matrix, including agent concentration, cleaning solution temperature, agitation and immersion time, rinse water amount and temperature, and use/non-use of drying air. Based on results of process development testing to date, several observations are offered: aqueous cleaning appears effective for steels and SermeTel-coated metals in ASRM processing; aqueous cleaning agents may stain and/or attack bare aluminum metals to various extents; aqueous cleaning appears unsuitable for thermal sprayed aluminum-coated steel; aqueous cleaning appears to adequately remove a wide range of contaminants from flat metal surfaces, but supplementary assistance may be needed to remove clumps of tenacious contaminants embedded in holes, etc.; and hot rinse water appears to be beneficial to aid in drying of bare steel and retarding oxidation rate.

  6. Replacing solvent cleaning with aqueous cleaning. Final report, March 1993-January 1994

    SciTech Connect

    Monroe, K.R.

    1994-08-01

    The report documents actions taken by Robert Bosch Corp., Charleston, SC, in replacing the cleaning solvents, 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) and trichloroethylene (TCE) with aqueous solutions. An early key decision was to replace their aging, large central degreasing stations with several small cleaning units, each designed and dedicated for cleaning just one part at one step in the product assembly process. The strategy demanded reassessment of each cleaning step and identification of apparatus and chemistry for optimizing each aqueous replacement. The report summarizes the actions taken to achieve aqueous cleaning for four typical components, previously cleaned with chlorinated solvents. The report provides quantitative comparisons of cleaning performance and costs of the old chlorinated (1988) and the new aqueous (1992) cleaning methods.

  7. Three dimensional electrode for the electrolytic removal of contaminants from aqueous waste streams

    DOEpatents

    Spiegel, Ella F.; Sammells, Anthony F.

    2001-01-01

    Efficient and cost-effective electrochemical devices and processes for the remediation of aqueous waste streams. The invention provides electrolytic cells having a high surface area spouted electrode for removal of heavy metals and oxidation of organics from aqueous environments. Heavy metal ions are reduced, deposited on cathode particles of a spouted bed cathode and removed from solution. Organics are efficiently oxidized at anode particles of a spouted bed anode and removed from solution. The method of this inventions employs an electrochemical cell having an anolyte compartment and a catholyte compartment, separated by a microporous membrane, in and through which compartments anolyte and catholyte, respectively, are circulated. A spouted-bed electrode is employed as the cathode for metal deposition from contaminated aqueous media introduced as catholyte and as the anode for oxidation of organics from contaminated aqueous media introduced as anolyte.

  8. Behaviors of acrylamide/itaconic acid hydrogels in uptake of uranyl ions from aqueous solutions

    SciTech Connect

    Karadag, E.; Saraydin, D.; Gueven, O.

    1995-12-01

    In this study, adsorptions of uranyl ions from two different aqueous uranyl solutions by acrylamide-itaconic acid hydrogels were investigated by a spectroscopic method. The hydrogels were prepared by irradiating with {gamma}-radiation. In the experiment of uranyl ions adsorption, Type II adsorption was found. One gram of acrylamide-itaconic acid hydrogels sorbed 178-219 mg uranyl ions from the solutions of uranyl acetate, 42-76 mg uranyl ions from the aqueous solutions of uranyl nitrate, while acrylamide hydrogel did not sorb any uranyl ion. For the hydrogel containing 40 mg of itaconic acid and irradiated to 3.73 kGy, swelling of the hydrogels was observed in water (1660%), in the aqueous solution of uranyl acetate (730%), and in the aqueous solution of uranyl nitrate (580%). Diffusions of water onto hydrogels were a non-Fickian type of diffusion, whereas diffusions of uranyl ions were a Fickian type of diffusion.

  9. In honour of N. Yngve Öhrn: surveying proton cancer therapy reactions with Öhrn's electron nuclear dynamics method. Aqueous clusters radiolysis and DNA-base damage by proton collisions

    NASA Astrophysics Data System (ADS)

    Mclaurin, Patrick M.; Privett, Austin J.; Stopera, Christopher; Grimes, Thomas V.; Perera, Ajith; Morales, Jorge A.

    2015-02-01

    Proton cancer therapy (PCT) utilises high-energy H+ projectiles to cure cancer. PCT healing arises from its DNA damage in cancerous cells, which is mostly inflicted by the products from PCT water radiolysis reactions. While clinically established, a complete microscopic understanding of PCT remains elusive. To help in the microscopic elucidation of PCT, Professor Öhrn's simplest-level electron nuclear dynamics (SLEND) method is herein applied to H+ + (H2O)3-4 and H+ + DNA-bases at ELab = 1.0 keV. These are two types of computationally feasible prototypes to study water radiolysis reactions and H+-induced DNA damage, respectively. SLEND is a time-dependent, variational, non-adiabatic and direct-dynamics method that adopts a nuclear classical-mechanics description and an electronic single-determinantal wavefunction. Additionally, our SLEND + effective-core-potential method is herein employed to simulate some computationally demanding PCT reactions. Due to these attributes, SLEND proves appropriate for the simulation of various types of PCT reactions accurately and feasibly. H+ + (H2O)3-4 simulations reveal two main processes: H+ projectile scattering and the simultaneous formation of H and OH fragments; the latter process is quantified through total integrals cross sections. H+ + DNA-base simulations reveal atoms and groups displacements, ring openings and base-to-proton electron transfers as predominant damage processes. The authors warmly dedicate this SLEND investigation in honour of Professor N. Yngve Öhrn on the occasion of his 80th birthday celebration during the 54th Sanibel Symposium in St. Simons' Island, Georgia, on February 16-21, 2014. Associate Professor Jorge A. Morales was a former chemistry PhD student under the mentorship of Professor Öhrn and Dr Ajith Perera took various quantum chemistry courses taught by Professor Öhrn during his chemistry PhD studies. Both Jorge and Ajith look back to those great times of their scientific formation under

  10. Aqueous phase removal of nitrogen from nitrogen compounds

    DOEpatents

    Fassbender, Alex G.

    1993-01-01

    A method is disclosed for denitrification of compounds containing nitrogen present in aqueous waste streams. The method comprises the steps of (1) identifying the types of nitrogen compounds present in a waste stream, (2) determining the concentrations of nitrogen compounds, (3) balancing oxidized and reduced form of nitrogen by adding a reactant, and (4) heating the mixture to a predetermined reaction temperature from about 300.degree. C. to about 600.degree. C., thereby resulting in less harmful nitrogen and oxygen gas, hydroxides, alcohols, and hydrocarbons.

  11. Preparation of thin ceramic films via an aqueous solution route

    DOEpatents

    Pederson, Larry R.; Chick, Lawrence A.; Exarhos, Gregory J.

    1989-01-01

    A new chemical method of forming thin ceramic films has been developed. An aqueous solution of metal nitrates or other soluble metal salts and a low molecular weight amino acid is coated onto a substrate and pyrolyzed. The amino acid serves to prevent precipitation of individual solution components, forming a very viscous, glass-like material as excess water is evaporated. Using metal nitrates and glycine, the method has been demonstrated for zirconia with various levels of yttria stabilization, for lanthanum-strontium chromites, and for yttrium-barium-copper oxide superconductors on various substrates.

  12. Immunological study of the aqueous humor in ocular herpes simplex.

    PubMed

    Denis, J

    1976-01-01

    (1) Isolation of herpetic virus and immunological studies of the serum and aqueous humor are two complementary methods of investigation in the diagnosis of ocular herpes simplex infection, their relative value depending on the clinical situation. (2) Of the different immunological techniques that of antibody titration by the hemagglutination method is an easy, sensitive test, but only if the Goldmann-Witner ratio is calculated. By this technique, the diagnosis of herpetic infection can be made in unusual clinical presentations or old cases in which all specificity had disappeared.

  13. Aqueous Cleaning and Validation for Space Shuttle Propulsion Hardware at the White Sands Test Facility

    NASA Technical Reports Server (NTRS)

    Hornung, Steven D.; Biesinger, Paul; Kirsch, Mike; Beeson, Harold; Leuders, Kathy

    1999-01-01

    The NASA White Sands Test Facility (WSTF) has developed an entirely aqueous final cleaning and verification process to replace the current chlorofluorocarbon (CFC) 113 based process. This process has been accepted for final cleaning and cleanliness verification of WSTF ground support equipment. The aqueous process relies on ultrapure water at 50 C (323 K) and ultrasonic agitation for removal of organic compounds and particulate. The cleanliness is verified bv determining the total organic carbon (TOC) content and filtration with particulate counting. The effectiveness of the aqueous methods for detecting hydrocarbon contamination and particulate was compared to the accepted CFC 113 sampling procedures. Testing with known contaminants, such as hydraulic fluid and cutting and lubricating oils, to establish a correlation between aqueous TOC and CFC 113 nonvolatile residue (NVR) was performed. Particulate sampling on cleaned batches of hardware that were randomly separated and sampled by the two methods was performed. This paper presents the approach and results, and discusses the issues in establishing the equivalence of aqueous sampling to CFC 113 sampling, while describing the approach for implementing aqueous techniques on Space Shuttle Propulsion hardware.

  14. Aqueous Alteration on Mars. Chapter 23

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Morris, Richard V.; Clark, Benton C.

    2007-01-01

    Aqueous alteration is the change in composition of a rock, produced in response to interactions with H2O-bearing ices, liquids, and vapors by chemical weathering. A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Mineralogical indicators for aqueous alteration include goethite (lander), jarosite (lander), kieserite (orbiter), gypsum (orbiter) and other Fe-, Mg-, and Ca-sulfates (landers), halides (meteorites, lander), phyllosilicates (orbiter, meteorites), hematite and nanophase iron oxides (telescopic, orbiter, lander), and Fe-, Mg-, and Ca-carbonates (meteorites). Geochemical indicators (landers only) for aqueous alteration include Mg-, Ca-, and Fe-sulfates, halides, and secondary aluminosilicates such as smectite. Based upon these indicators, several styles of aqueous alteration have been suggested on Mars. Acid-sulfate weathering (e.g., formation of jarosite, gypsum, hematite, and goethite), may occur during (1) the oxidative weathering of ultramafic igneous rocks containing sulfides, (2) sulfuric acid weathering of basaltic materials, and (3) acid fog (i.e., vapors rich in H2SO4) weathering of basaltic or basaltic-derived materials. Near-neutral or alkaline alteration occurs when solutions with pH near or above 7 move through basaltic materials and form phases such as phyllosilicates and carbonates. Very low water:rock ratios appear to have been prominent at most of the sites visited by landed missions because there is very little alteration (leaching) of the original basaltic composition (i.e., the alteration is isochemical or in a closed hydrologic system). Most of the aqueous alteration appears to have occurred early in the history of the planet (3 to 4.5 billion years ago); however, minor aqueous alteration may be occurring at the

  15. Anti-Inflammatory Activity of Aqueous Extract of Beta Vulgaris L.

    PubMed Central

    Jain, Swati; Garg, Vipin Kumar; Sharma, Pramod Kumar

    2011-01-01

    The present study deals with the investigation of phytochemically evaluated aqueous extract of leaves of Beta vulgaris for its anti-inflammatory activity. The anti-inflammatory activity was evaluated by carrageenan induced rat paw oedema method for acute inflammation and cotton pellet granuloma method for chronic inflammation. The standard drug used was indomethacin (10 mg/kg) for both the models. In both methods, aqueous extract at a dose level of 1000 mg/kg has shown significant activity which is comparable to that of the standard PMID:24826006

  16. Evolution of hydrogen from acidic aqueous and aqueous-alcoholic solutions by reduced forms of isopolytungstates

    SciTech Connect

    Saidkhanov, S.S.; Parmon, V.N.; Savinov, E.N.

    1986-02-10

    The authors determine the specific nature of the hydrogen-releasing polytungstate (PT) species and investigate the features of H/sub 2/ evolution by this species. In aqueous and aqueous-alcohol solutions, reoxidation of the doubly reduced form of hexatungstate proceeds spontaneously, accompanied by hydrogen evolution; in contrast, the reduced form of the PT is stable with respect to reoxidation.

  17. METHOD OF REDUCING PLUTONIUM COMPOUNDS

    DOEpatents

    Johns, I.B.

    1958-06-01

    A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

  18. Aqueous outflow: Segmental and distal flow

    PubMed Central

    Swaminathan, Swarup S.; Oh, Dong-Jin; Kang, Min Hyung; Rhee, Douglas J.

    2014-01-01

    A prominent risk factor of primary open-angle glaucoma is ocular hypertension, a pathologic state caused by impaired outflow of aqueous humor through the trabecular meshwork within the iridocorneal angle. The juxtacanalicular region of the trabecular meshwork and the inner wall of Schlemm canal have been identified as the main contributors to aqueous outflow resistance, and both extracellular matrix within the trabecular meshwork and trabecular meshwork cell shape have been shown to affect outflow. Overexpression of multiple ECM proteins in perfused cadaveric human eyes has led to increased outflow resistance and elevated IOP. Pharmacologic agents targeting trabecular meshwork cytoskeletal arrangements have been developed after multiple studies demonstrated the importance of cell shape on outflow. Several groups have shown that aqueous outflow occurs only at certain segments of the trabecular meshwork circumferentially, a concept known as segmental flow. This is based on the theory that aqueous outflow is dependent on the presence of discrete pores within the Schlemm canal. Segmental flow has been described in the eyes of multiple species, including primate, bovine, mouse, and human samples. While the trabecular meshwork appears to be the major source of resistance, trabecular meshwork bypass procedures have been unable to achieve the degree of IOP reduction observed with trabeculectomy, reflecting the potential impact of distal flow, or flow through Schlemm canal and collector channels, on outflow. Multiple studies have demonstrated that outflow occurs preferentially near collector channels, suggesting that these distal structures may be more important to aqueous outflow than previously believed. PMID:25088623

  19. Performed surfactant-optimized aqueous alkaline flood

    SciTech Connect

    Thigpen, D.R.; Lawson, J.B.; Nelson, R.C.

    1991-11-26

    This paper describes improvement in a process for recovering oil from an acidic oil reservoir by injecting an aqueous alkaline solution comprising water, sodium chloride, and alkaline material for reacting with the reservoir oil forming a petroleum acid soap to form an in-situ surfactant system. The improvement comprises: selecting a preformed cosurfactant which is soluble in both the aqueous solution and the reservoir oil and has a solubility ratio which is grater than the solubility ratio of the petroleum acid soap where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; combining with the alkaline solution an amount of the preformed cosurfactant which will result in the in-situ surfacant system having a salinity about equal to a salinity which results in minimal interfacial tension between the oil in the reservoir and the in-situ surfactant system at reservoir temperature, wherein the amount of the preformed cosurfactant is about 0.3 percent by weight in the aqueous alkaline solution; and injecting the cosurfactant-aqueous alkaline solution mixture into the reservoir to displace oil toward a fluid production location.

  20. Synthesis and characterization of aqueous quantum dots for biomedical applications

    NASA Astrophysics Data System (ADS)

    Li, Hui

    Quantum Dots (QDs) are semiconductor nanocrystals (1˜20 nm) exhibiting distinctive photoluminescence (PL) properties due to the quantum confinement effect. Having many advantages over organic dyes, such as broad excitation and resistance to photobleaching, QDs are widely used in bioapplications as one of most exciting nanobiotechnologies. To date, most commercial QDs are synthesized through the traditional organometallic method and contain toxic elements, such as cadmium, lead, mercury, arsenic, etc. The overall goal of this thesis study is to develop an aqueous synthesis method to produce nontoxic quantum dots with strong emission and good stability, suitable for biomedical imaging applications. Firstly, an aqueous, simple, environmentally friendly synthesis method was developed. With cadmium sulfide (CdS) QDs as an example system, various processing parameters and capping molecules were examined to improve the synthesis and optimize the PL properties. The obtained water soluble QDs exhibited ultra small size (˜5 nm), strong PL and good stability. Thereafter, using the aqueous method, the zinc sulfide (ZnS) QDs were synthesized with different capping molecules, i.e., 3-mercaptopropionic acid (MPA) and 3-(mercaptopropyl)trimethoxysilane (MPS). Especially, via a newly developed capping molecule replacement method, the present ZnS QDs exhibited bright blue emission with a quantum yield of 75% and more than 60 days lifetime in the ambient conditions. Two cytotoxicity tests with human endothelial cells verified the nontoxicity of the ZnS QDs by cell counting with Trypan blue staining and fluorescence assay with Alamar Blue. Taking advantage of the versatile surface chemistry, several strategies were explored to conjugate the water soluble QDs with biomolecules, i.e., antibody and streptavidin. Accordingly, the imaging of Salmonella t. cells and biotinylated microbeads has been successfully demonstrated. In addition, polyethylenimine (PEI)-QDs complex was formed and

  1. Aqueous VEGF as a Predictor of Macular Thickening Following Cataract Surgery in Patients with Diabetes Mellitus

    PubMed Central

    Hartnett, M. Elizabeth; Tinkham, Nicholas; Paynter, Lauren; Geisen, Pete; Rosenberg, Pinchas; Koch, Gary; Cohen, Kenneth L

    2009-01-01

    Purpose To study associations between serum and aqueous vascular endothelial growth factor (VEGF) and insulin-like growth factor 1 (IGF-1) and macular edema measured with optical coherence tomography (OCT) following phacoemulsification in diabetic patients. Design Cohort study Methods A pilot study of 36 consecutive diabetic patients undergoing planned phacoemulsification with IOL in one eye by one surgeon at the University of North Carolina consented to preoperative and postoperative OCT central subfield thickness measurements (CSF) and aqueous and blood samples for VEGF and IGF-1. Four patients with CSME received laser preoperatively. Spearman Rank correlations were performed between growth factors and mean CSF or a clinically meaningful percent change in CSF (>11% of preoperative measurement) at one and 6 months postoperatively. Results There were no surgical complications or new cases of CSME following surgery. Mean aqueous VEGF in patients with retinopathy, determined preoperatively, increased with increasing level of severity. Patients with preoperative CSME also had severe or worse retinopathy and the greatest mean aqueous VEGF. Significant preoperative correlations existed between aqueous VEGF and more severe retinopathy, whether CSME was present or absent (r=0.49, P=.007), and between aqueous VEGF and CSME (r=0.41, P=.029). At one month postoperative, aqueous VEGF was positively correlated with >11% change from preoperative CSF, regardless of CSME status (r=0.47; P=.027). No noteworthy associations existed between CSF and IGF-1 values. Conclusions Aqueous VEGF was significantly positively associated with a clinically meaningful change in CSF in diabetic patients one month following cataract surgery. Accounting for preoperative CSF was important. Further study is indicated. PMID:19837384

  2. Distinctive and pervasive alterations in aqueous humor protein composition following different types of glaucoma surgery

    PubMed Central

    Rosenfeld, Cyril; Lai, Xianyin; Witzmann, Frank A.; Price, Francis W.

    2015-01-01

    Purpose To investigate whether specific glaucoma surgeries are associated with differences in aqueous humor protein concentrations compared to eyes without filters. Methods In this cross-sectional study, aqueous humor samples were prospectively collected from control subjects who underwent routine cataract surgery (n=14) and from patients who had different glaucoma filters: Baerveldt aqueous shunt (n=6), Ahmed aqueous shunt (n=6), trabeculectomy (n=5), and Ex-Press trabeculectomy (n=3). Total protein concentrations were determined with Bradford assay. Tryptic digests were analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Proteins were identified with high confidence using stringent criteria and were quantitatively compared with a label-free platform. Relative protein quantities were compared across groups with ANOVA. Post hoc pair-wise comparisons were adjusted for multiple comparisons. Results Compared to the control eyes, the aqueous humor protein concentration was increased approximately tenfold in the Ahmed and Baerveldt eyes and fivefold in the trabeculectomy and Ex-Press eyes. Overall, 718 unique proteins, splice variants, or isoforms were identified. No differences in the protein concentrations were detected between the Baerveldt and Ahmed groups. Likewise, the trabeculectomy and Ex-Press groups were remarkably similar. Therefore, the aqueous shunt groups were pooled, and the trabeculectomy groups were pooled for a three-way comparison with the controls. More than 500 proteins differed significantly in relative abundance (ANOVA p<0.01) among the control, aqueous shunt, and trabeculectomy groups. Functional analyses suggested these alterations in relative protein abundance affected dozens of signaling pathways. Conclusions Different glaucoma surgical procedures were associated with marked increases in the aqueous humor protein concentration and distinctive changes in the relative abundance of numerous proteins involved in multiple

  3. SEPARATION OF RUTHENIUM FROM AQUEOUS SOLUTIONS

    DOEpatents

    Callis, C.F.; Moore, R.L.

    1959-09-01

    >The separation of ruthenium from aqueous solutions containing uranium plutonium, ruthenium, and fission products is described. The separation is accomplished by providing a nitric acid solution of plutonium, uranium, ruthenium, and fission products, oxidizing plutonium to the hexavalent state with sodium dichromate, contacting the solution with a water-immiscible organic solvent, such as hexone, to extract plutonyl, uranyl, ruthenium, and fission products, reducing with sodium ferrite the plutonyl in the solvent phase to trivalent plutonium, reextracting from the solvent phase the trivalent plutonium, ruthenium, and some fission products with an aqueous solution containing a salting out agent, introducing ozone into the aqueous acid solution to oxidize plutonium to the hexavalent state and ruthenium to ruthenium tetraoxide, and volatizing off the ruthenium tetraoxide.

  4. RECOVERY OF PROTACTINIUM FROM AQUEOUS SOLUTIONS

    DOEpatents

    Elson, R.E.

    1959-07-14

    The recovery of fluoride complexed protactinium from aqueous acidic solutions by solvent extraction is described. Generally the prccess of the invention com rises mixing an aqueous solution containing protactinium in a complexed form with an organic solvent which is specific for protactinium, such as diisopropyl carbinol, then decomposing the protactinium complex by adjusting the acidity of the aqueous solution to between 0-3 to 0-9 M in hydrogen ion concentration, and introducing a source of aluminum ions in sufficient quantity to establish a concentration of 0.5 to 1.2 M aluminum ion, whereupon decomposition of the protactinium fluoride complex takes place and the protactinium ion is taken up by the organic solvent phase.

  5. The aqueous reference for ESR oximetry

    NASA Astrophysics Data System (ADS)

    Diakova, Galina; Bryant, Robert G.

    2006-02-01

    The interaction of molecular oxygen with derivatives of nitroxide EPR spin labels has been investigated using nuclear spin-relaxation spectroscopy in aqueous and nonaqueous solvents. The proton spin-lattice relaxation rate induced by oxygen provides a measure of the local concentration of oxygen, which we find is dependent on solvent. In water, the hydrophobic effect increases the local concentration of oxygen in the nonpolar portions of solute molecules. For nitroxides reduced to the hydroxylamine in aqueous solutions, we find that the local concentration of oxygen is approximately twice that associated with a free diffusion hard sphere limit, while in octane, this effect is absent. These results show that nitroxide based ESR oximetry may suffer a reference concentration shift of order a factor of two if the aqueous nitroxide spectrum or relaxation is used as the reference.

  6. RUTHENIUM DECONTAMINATION METHOD

    DOEpatents

    Gresky, A.T.

    1960-07-19

    A liquid-liquid extraction method of separating uranium from fission products is given. A small amount of a low molecular weight ketone is added to an acidic aqueous solution containing neutron-irradiated uranium and its associated fission products. The resulting solution is digested and then contacted with an organic liquid that extracts uranium values. The purpose of the step of digesting the aqueous solution in the presence of the ketone is to suppress the extractability of ruthenium.

  7. METHOD OF SEPARATING PLUTONIUM

    DOEpatents

    Heal, H.G.

    1960-02-16

    BS>A method of separating plutonium from aqueous nitrate solutions of plutonium, uranium. and high beta activity fission products is given. The pH of the aqueous solution is adjusted between 3.0 to 6.0 with ammonium acetate, ferric nitrate is added, and the solution is heated to 80 to 100 deg C to selectively form a basic ferric plutonium-carrying precipitate.

  8. Photochemistry of dihydrobiopterin in aqueous solution.

    PubMed

    Vignoni, Mariana; Cabrerizo, Franco M; Lorente, Carolina; Claparols, Catherine; Oliveros, Esther; Thomas, Andrés H

    2010-02-21

    Dihydrobiopterin (H(2)Bip) and its oxidized analogue, biopterin (Bip), accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder in which the protection against UV radiation fails. The photochemistry of H(2)Bip was studied in neutral aqueous solutions upon UV-A irradiation (320-400 nm) at room temperature. The photochemical reactions were followed by UV/vis spectrophotometry, HPLC and enzymatic methods for hydrogen peroxide (H(2)O(2)) determination. Photoproducts were analyzed by means of electrospray ionization mass spectrometry. Under anaerobic conditions, excitation of H(2)Bip leads to the formation of at least two isomeric dimers with molecular masses equal to exactly twice the molecular mass of the reactant. This reaction takes place from the singlet excited state of the reactant. To the best of our knowledge, this is the first time that the photodimerization of a dihydropterin is reported. In the presence of air, the dimers are again the main photoproducts at the beginning of the reaction, but a small proportion of the reactant is converted into Bip. As the reaction proceeds and enough Bip accumulates in the solution, a photosensitized process starts, where Bip photoinduces the oxidation of H(2)Bip to Bip, and H(2)O(2) is formed. As a consequence, the rates of H(2)Bip consumption and Bip formation increase as a function of irradiation time, resulting in an autocatalytic photochemical process. In this process, Bip in its triplet excited state reacts with the ground state of H(2)Bip. The mechanisms involved are analyzed and the biological implications of the results are discussed.

  9. IMPACT OF EVAPORATION ON AQUEOUS TEAR LOSS

    PubMed Central

    McCulley, James P.; Uchiyama, Eduardo; Aronowicz, Joel D.; Butovich, Igor A.

    2006-01-01

    Purpose To determine the impact of evaporation on preocular aqueous tear (AT) loss in normal subjects (controls) and patients with keratoconjunctivitis sicca (KCS). Methods Eighteen patients (32 eyes) with KCS with or without associated meibomian gland dysfunction (MGD) and 11 sex-matched controls had AT evaporation determined between relative humidity (RH) of 20% and 45% using an evaporometer. AT volume, flow, and turnover were determined with a fluorophotometer. Results Evaporative rates increased significantly when the RH was changed from 40%–45% to 20%–25% (P < .001). This change was similar in all groups and on average accounted for a 99.43% increase. There were no statistically significant differences in evaporative rate between controls, the KCS alone group, and the KCS/MGD group. Dry eye patients exhibited a decreased tear turnover when compared to controls. Evaporative contribution to tear loss at 40%–45% RH was 23.47% for controls, 30.99% for “classic” KCS patients, and 25.44% for KCS/MGD patients. At 20%–25% RH, the evaporative contribution was 41.66% for controls, 57.67% for classic KCS patients, and 50.28% for KCS/MGD patients. Conclusions RH significantly impacts evaporation regardless of the presence of dry eye disease and probably accounts for the increased dry eye symptoms in people (controls and dry eye patients) in conditions of low RH (eg, deserts, airplane cabins, cold dry seasons). Contribution of evaporation to tear loss tends to be higher than previously described. The percent contribution is dependent on environmental conditions such as RH. There was a trend toward increased contribution to AT loss in dry eye patients vs controls, but statistical significance was not reached. PMID:17471332

  10. Stable aqueous colloidal solutions of intact surfactant-free graphene nanoribbons and related graphitic nanostructures.

    PubMed

    Dimiev, Ayrat M; Gizzatov, Ayrat; Wilson, Lon J; Tour, James M

    2013-04-01

    Here we demonstrate a simple, nondestructive method for the preparation of stable aqueous colloidal solutions of graphene nanoribbons and carbon nanotubes. The method includes sonication of carbon nanomaterials in hypophosphorous acid, filtration accompanied by washing the solids with water and dispersion of the solids in a fresh portion of water to form colloidal solutions.

  11. Stable aqueous colloidal solutions of intact surfactant-free graphene nanoribbons and related graphitic nanostructures.

    PubMed

    Dimiev, Ayrat M; Gizzatov, Ayrat; Wilson, Lon J; Tour, James M

    2013-04-01

    Here we demonstrate a simple, nondestructive method for the preparation of stable aqueous colloidal solutions of graphene nanoribbons and carbon nanotubes. The method includes sonication of carbon nanomaterials in hypophosphorous acid, filtration accompanied by washing the solids with water and dispersion of the solids in a fresh portion of water to form colloidal solutions. PMID:23435853

  12. Atomistic insights into aqueous corrosion of copper.

    SciTech Connect

    Jeon, B.; Sankaranarayanan, S. K. R. S.; van Duin, A. C. T.; Ramanathan, S.

    2011-06-21

    Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl{sup -} concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper.

  13. Separation of metal ions from aqueous solutions

    SciTech Connect

    Almon, A.

    1991-12-31

    This invention is comprised of a process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flowing cell containing flowing bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flowing cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flowing cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

  14. Separation of metal ions from aqueous solutions

    DOEpatents

    Almon, Amy C.

    1994-01-01

    A process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flow cell containing flow bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flow cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flow cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

  15. Stable Aqueous Dispersion of Exfoliated Graphene for Tribological Applications.

    PubMed

    Liang, Shuaishuai; Shen, Zhigang; Yi, Min; Liu, Lei; Cai, Chujiang; Zhang, Xiaojing; Ma, Shulin

    2016-02-01

    In this study, the directly exfoliated graphene prepared by a jet cavitation method was tested as additive in pure water toward tribological applications. Reductions of friction coefficient and wear volume up to 22.8% and 44.4% respectively were achieved by addition of the graphene flakes. The as-prepared aqueous graphene dispersions exhibited high stability against sedimentation, and concurrently maintained their tribological properties after deposited for 15 days. The improvement in lubricating and anti-wear performances can be attributed to the graphene network formed on the sliding surfaces during the test. PMID:27433609

  16. Hydrate-based heavy metal separation from aqueous solution

    NASA Astrophysics Data System (ADS)

    Song, Yongchen; Dong, Hongsheng; Yang, Lei; Yang, Mingjun; Li, Yanghui; Ling, Zheng; Zhao, Jiafei

    2016-02-01

    A novel hydrate-based method is proposed for separating heavy metal ions from aqueous solution. We report the first batch of experiments and removal characteristics in this paper, the effectiveness and feasibility of which are verified by Raman spectroscopy analysis and cross-experiment. 88.01-90.82% of removal efficiencies for Cr3+, Cu2+, Ni2+, and Zn2+ were obtained. Further study showed that higher R141b-effluent volume ratio contributed to higher enrichment factor and yield of dissociated water, while lower R141b-effluent volume ratio resulted in higher removal efficiency. This study provides insights into low-energy, intensive treatment of wastewater.

  17. Non-aqueous electrolytes for lithium ion batteries

    SciTech Connect

    Chen, Zonghai; Amine, Khalil

    2015-11-12

    The present invention is generally related to electrolytes containing anion receptor additives to enhance the power capability of lithium-ion batteries. The anion receptor of the present invention is a Lewis acid that can help to dissolve LiF in the passivation films of lithium-ion batteries. Accordingly, one aspect the invention provides electrolytes comprising a lithium salt; a polar aprotic solvent; and an anion receptor additive; and wherein the electrolyte solution is substantially non-aqueous. Further there are provided electrochemical devices employing the electrolyte and methods of making the electrolyte.

  18. RECOVERY OF URANIUM FROM AQUEOUS PHOSPHATE-CONTAINING SOLUTIONS

    DOEpatents

    Igelsrud, I.; Stephen, E.F.

    1959-08-11

    ABS>A method is presented for recovering hexavalent uranium from an acidic phosphaie solution. A high molecular weight amine, such as a mixture of cccoanut oil amines, is added to the solution in such amount as to give a ratio of about 2000 parts by weight of amine to 1 part by weight of uranium. The uranium is precipitated with the amines and the whole filtered from the solution. The uranium is leached from the amine mass by washing with aqueous sodium carbonate solution; and the amine mixture is available for reuse.

  19. Cytogenetic changes induced by aqueous ferrofluids in agricultural plants

    NASA Astrophysics Data System (ADS)

    Răcuciu, Mihaela; Creangă, Dorina

    2007-04-01

    In this paper, the authors present their results regarding the cellular division rate and the percentage of chromosomal aberrations in the root meristematic cells of agricultural plants when cultivated in the presence of different concentrations of aqueous ferrofluid, ranging between 10 and 250 μL/L. The agricultural species ( Zea mays) with a major role in the life of people was chosen for the experimental project. The water-based ferrofluid was prepared following the chemical co-precipitation method, using tetramethylammonium hydroxide as magnetite core stabilizer. Microscopic investigations (cytogenetic tests) resulted in the evaluation of the mitotic and chromosomal aberration index. They appeared to increase following ferrofluid addition.

  20. Oxidation of ammonium sulfite in aqueous solutions using ozone technology

    NASA Astrophysics Data System (ADS)

    Li, Yue; Shang, Kefeng; Lu, Na; Li, Jie; Wu, Yan

    2013-03-01

    How to deal with unstable ammonium sulfite, the byproduct of flue gas desulfuration by ammonia absorption methods, has been a difficult problem in recent years. Oxidation of ammonium sulfite in aqueous solutions using ozone produced by a surface discharge system was investigated in the paper. The oxidation efficiency of ammonium sulfite by ozone and traditional air aeration were compared, and the factors including ozone concentration, gas flow rate, initial concentration of ammonium sulfite solution and reaction temperature were discussed. The results show that the oxidation efficiency of ammonium sulfite by ozone technology reached nearly 100% under the optimum conditions, which had a significant increase compared with that by air aeration.

  1. Method for the chromatographic separation of cations from aqueous samples

    DOEpatents

    Horwitz, E. Philip; Chiarizia, Renato; Dietz, Mark L.

    1997-01-01

    An extraction chromatographic material for extracting metal cations from a iquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methanediphosphonic acid on an inert particulate support.

  2. Method for the chromatographic separation of cations from aqueous samples

    DOEpatents

    Horwitz, E.P.; Chiarizia, R.; Dietz, M.L.

    1997-07-29

    An extraction chromatographic material is described for extracting metal cations from a liquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methanediphosphonic acid on an inert particulate support. 7 figs.

  3. Method for the chromatographic separation of cations from aqueous samples

    DOEpatents

    Horwitz, E.P.; Chiarizia, R.; Dietz, M.L.

    1998-12-22

    An extraction chromatographic material is described for extracting metal cations from a liquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methane-diphosphonic acid on an inert particulate support. 7 figs.

  4. Method for the chromatographic separation of cations from aqueous samples

    DOEpatents

    Horwitz, E. Philip; Chiarizia, Renato; Dietz, Mark L.

    1998-12-22

    An extraction chromatographic material for extracting metal cations from a liquid stream. The extraction chromatographic material is prepared by adsorbing a diesterified methanediphosphonic acid on an inert particulate support.

  5. Preparation of metallic nanoparticles by irradiation in starch aqueous solution

    SciTech Connect

    Nemţanu, Monica R. Braşoveanu, Mirela Iacob, Nicuşor

    2014-11-24

    Colloidal silver nanoparticles (AgNPs) were synthesized in a single step by electron beam irradiation reduction of silver ions in aqueous solution containing starch. The nanoparticles were characterized by spectrophotocolorimetry and compared with those obtained by chemical (thermal) reduction method. The results showed that the smaller sizes of AgNPs were prepared with higher yields as the irradiation dose increased. The broadening of particle size distribution occurred by increasing of irradiation dose and dose rate. Chromatic parameters such as b* (yellow-blue coordinate), C* (chroma) and ΔE{sub ab} (total color difference) could characterize the nanoparticles with respect of their concentration. Hue angle h{sup o} was correlated to the particle size distribution. Experimental data of the irradiated samples were also subjected to factor analysis using principal component extraction and varimax rotation in order to reveal the relation between dependent variables and independent variables and to reduce their number. The radiation-based method provided silver nanoparticles with higher concentration and narrower size distribution than those produced by chemical reduction method. Therefore, the electron beam irradiation is effective for preparation of silver nanoparticles using starch aqueous solution as dispersion medium.

  6. Preparation of metallic nanoparticles by irradiation in starch aqueous solution

    NASA Astrophysics Data System (ADS)

    NemÅ£anu, Monica R.; Braşoveanu, Mirela; Iacob, Nicuşor

    2014-11-01

    Colloidal silver nanoparticles (AgNPs) were synthesized in a single step by electron beam irradiation reduction of silver ions in aqueous solution containing starch. The nanoparticles were characterized by spectrophotocolorimetry and compared with those obtained by chemical (thermal) reduction method. The results showed that the smaller sizes of AgNPs were prepared with higher yields as the irradiation dose increased. The broadening of particle size distribution occurred by increasing of irradiation dose and dose rate. Chromatic parameters such as b* (yellow-blue coordinate), C* (chroma) and ΔEab (total color difference) could characterize the nanoparticles with respect of their concentration. Hue angle ho was correlated to the particle size distribution. Experimental data of the irradiated samples were also subjected to factor analysis using principal component extraction and varimax rotation in order to reveal the relation between dependent variables and independent variables and to reduce their number. The radiation-based method provided silver nanoparticles with higher concentration and narrower size distribution than those produced by chemical reduction method. Therefore, the electron beam irradiation is effective for preparation of silver nanoparticles using starch aqueous solution as dispersion medium.

  7. Effect of temperature, fluid composition, and flow rate on sandstones: implications for enhanced oil recovery methods. Final report for 1983/1984 SOMED project

    SciTech Connect

    Donahoe, R.J.

    1984-09-01

    The goal of this project is to develop, through experimentation and computer modelling, a predictive model for fluid injection enhanced oil recovery methods. Such a model will make possible accurate risk assessment before fluid injection programs are implemented, and therefore help to prevent costly field trial and error. The specific objectives of this study are to: (1) establish the experimental and computational facilities needed to conduct the remaining project objectives, (2) carry out a series of flow-through experiments, collecting data on the effect of T, flow rate, and fluid/solid composition on sample permeability and mineralogy, (3) develop a predictive geochemical model for mineral reactions which affect reservoir permeability, and (4) test the accuracy of the model using case histories and field tests. The first objective was scheduled for completion during the first project period (2/1/84 through 8/15/84). The tasks for the first project period are discussed in terms of their results and their status with respect to the original project task schedule. All project tasks scheduled for the first year have been completed on or ahead of schedule, with the exception of the testing of the flow-through system. This task will be completed shortly and the experimental portion of the project (objective 2) will soon be underway. 4 references, 1 figure.

  8. ADSORPTION OF CERIUM VALUES FROM AQUEOUS SOLUTIONS

    DOEpatents

    Roberts, F.P.

    1963-08-13

    Cerium can be removed from aqueous nitric acid (2 to 13 M) solutions by passing the latter over a PbO/sub 2/-containing anion exchange resin. The cerium is taken up by the resin, while any lanthanides, yttrium, and strontium present remain in the solution. (AEC)

  9. Aqueous rust-inhibiting and lubricating compositions

    SciTech Connect

    Brandolese, E.

    1983-06-14

    Rust-inhibiting compounds, especially for aqueous systems such as tool-lubricating emulsions for machine tools and which consist of amine salts of a number of monoaminoalkylene dicarboxylic acids are disclosed. These rust-inhibitors are used in combination with water and an alkanolamine. Examples and test results are given.

  10. Blast wave mitigation by dry aqueous foams

    NASA Astrophysics Data System (ADS)

    Del Prete, E.; Chinnayya, A.; Domergue, L.; Hadjadj, A.; Haas, J.-F.

    2013-02-01

    This paper presents results of experiments and numerical modeling on the mitigation of blast waves using dry aqueous foams. The multiphase formalism is used to model the dry aqueous foam as a dense non-equilibrium two-phase medium as well as its interaction with the high explosion detonation products. New experiments have been performed to study the mass scaling effects. The experimental as well as the numerical results, which are in good agreement, show that more than an order of magnitude reduction in the peak overpressure ratio can be achieved. The positive impulse reduction is less marked than the overpressures. The Hopkinson scaling is also found to hold particularly at larger scales for these two blast parameters. Furthermore, momentum and heat transfers, which have the main dominant role in the mitigation process, are shown to modify significantly the classical blast wave profile and thereafter to disperse the energy from the peak overpressure due to the induced relaxation zone. In addition, the velocity of the fireball, which acts as a piston on its environment, is smaller than in air. Moreover, the greater inertia of the liquid phase tends to project the aqueous foam far from the fireball. The created gap tempers the amplitude of the transmitted shock wave to the aqueous foam. As a consequence, this results in a lowering of blast wave parameters of the two-phase spherical decaying shock wave.

  11. Chemical Equilibrium Composition of Aqueous Systems

    1996-12-30

    MINEQL is a subroutine package to calculate equilibrium composition of an aqueous system, accounting for mass transfer. MINEQL-EIR contains an additional base on enthalpy and heat capacity data and has the option to do calculations at temperatures different from 25 degrees C.

  12. AQUEOUS CLEANING OF PRINTED CIRCUIT BOARD STENCILS

    EPA Science Inventory

    The USEPA through NRMRL has partnered with the California Dept. of Toxic Substance Control under an ETV Pilot Project to verigy polllution prevention, recycling and waste treatment technologies. One of the projects selected for verification was the ultrasonic aqueous cleaning tec...

  13. PHOTOREACTION OF VALEROPHENONE IN AQUEOUS SOLUTION

    EPA Science Inventory

    Kinetics and products of the photoreaction of the phenyl ketone valerophenone were investigated as a function of temperature, pH, and wavelength in aqueous solution. Under these conditions (<10-4M), the photoreactions are pseudo-first-order with respect to valerophenone concentra...

  14. Low temperature aqueous desulfurization of coal

    DOEpatents

    Slegeir, W.A.; Healy, F.E.; Sapienza, R.S.

    1985-04-18

    This invention describes a chemical process for desulfurizing coal, especially adaptable to the treatment of coal-water slurries, at temperatures as low as ambient, comprising treating the coal with aqueous titanous chloride whereby hydrogen sulfide is liberated and the desulfurized coal is separated with the conversion of titanous chloride to titanium oxides.

  15. Low temperature aqueous desulfurization of coal

    DOEpatents

    Slegeir, William A.; Healy, Francis E.; Sapienza, Richard S.

    1985-01-01

    This invention describes a chemical process for desulfurizing coal, especially adaptable to the treatment of coal-water slurries, at temperatures as low as ambient, comprising treating the coal with aqueous titanous chloride whereby hydrogen sulfide is liberated and the desulfurized coal is separated with the conversion of titanous chloride to titanium oxides.

  16. Water & Aqueous Solutions. Final Progress Report

    SciTech Connect

    2002-08-09

    The Gordon Research Conference (GRC) on Water & Aqueous Solutions was held at Holderness School, New Hampshire, 8/4/02 thru 8/9/02. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  17. REPLACING SOLVENT CLEANING WITH AQUEOUS CLEANING

    EPA Science Inventory

    The report documents actions taken by Robert Bosch Corp., Charleston, SC, in replacing the cleaning solvents 1, 1, 2- trichloro-1, 2, 2-trifluoroethane (CFC-113) and trichloroethylene (TCE) with aqueous solutions. Bosch has succeeded in eliminating all their CFC-113 use and so f...

  18. Dispersant for aqueous slurry of coal powder

    SciTech Connect

    Moriyama, N.; Watanabe, S.; Yamamura, M.

    1982-05-18

    A dispersant for forming an aqueous slurry of coal powder having a good flowability, which comprises as the active ingredient at least one member selected from sulfonation products of polycyclic aromatic compounds which may have a hydrocarbon group as a substituent, salts thereof and formaldehyde condensates thereof.

  19. Tangential Ultrafiltration of Aqueous "Saccharomyces Cerevisiae" Suspensions

    ERIC Educational Resources Information Center

    Silva, Carlos M.; Neves, Patricia S.; Da Silva, Francisco A.; Xavier, Ana M. R. B.; Eusebio, M. F. J.

    2008-01-01

    Experimental work on ultrafiltration is presented to illustrate the practical and theoretical principles of this separation technique. The laboratory exercise comprises experiments with pure water and with aqueous "Saccharomyces cerevisiae" (from commercial Baker's yeast) suspensions. With this work students detect the characteristic phenomena…

  20. Hematin crystallization from aqueous and organic solvents

    NASA Astrophysics Data System (ADS)

    Ketchum, Megan A.; Olafson, Katy N.; Petrova, Elena V.; Rimer, Jeffrey D.; Vekilov, Peter G.

    2013-09-01

    Hematin crystallization is the main mechanism of detoxification of heme that is released in malaria-infected erythrocytes as a byproduct of the hemoglobin catabolism by the parasite. A controversy exists over whether hematin crystals grow from the aqueous medium of the parasite's digestive vacuole or in the lipid bodies present in the vacuole. To this end, we compare the basic thermodynamic and structural features of hematin crystallization in an aqueous buffer at pH 4.8, as in the digestive vacuole, and in water-saturated octanol that mimics the environment of the lipid nanospheres. We show that in aqueous solutions, hematin aggregation into mesoscopic disordered clusters is insignificant. We determine the solubility of the β-hematin crystals in the pH range 4.8-7.6. We image by atomic force microscopy crystals grown at pH 4.8 and show that their macroscopic and mesoscopic morphology features are incompatible with those reported for biological hemozoin. In contrast, crystals grown in the presence of octanol are very similar to those extracted from parasites. We determine the hematin solubility in water-saturated octanol at three temperatures. These solubilities are four orders of magnitude higher than that at pH 4.8, providing for faster crystallization from organic than from aqueous solvents. These observations further suggest that the lipid bodies play a role in mediating biological hemozoin crystal growth to ensure faster heme detoxification.

  1. Adsorption of aqueous copper on peanut hulls

    NASA Astrophysics Data System (ADS)

    Davis, Kanika Octavia

    A method was established for measuring the adsorption of Cu(II) from aqueous solution to unmodified and modified peanut hulls at constant temperature and pH. Modification of the hulls was performed by oxidation with alkaline hydrogen peroxide. During the modification process, the hydrogen peroxide solubilizes the lignin component, making the surface more porous which increases the availability of binding sites, while simultaneously oxidizing the cellulose. The oxidation of alcohol groups creates more binding sites by creating functional groups such as COO-, which increases chelation to metal ions. Fourier transform infrared spectroscopy confirms delignification of the peanut hulls by the disappearance of carboxyl peaks of the modified hulls, which were originally produced from the lignin content. Although, oxidation is not fully confirmed, it is not ruled out because the expected carboxylate peak (1680 cm-1) maybe overshadowed by a broad peak due to OH bending of water adsorbed to the hulls. Hulls adsorbed copper from solutions in the concentration range of 50-1000 ppm of CuCl2. Concentrations of pre- and post-adsorption solutions were determined using inductively coupled plasma optical emission spectroscopy. The adsorption isotherms were fit to known two and three-parameter models, evaluated and the binding mechanism was inferred. Maximum surface coverage was 3.5 +/- 0.6 mg Cu2+ /g hull for unmodified hulls and 11 +/- 1 mg Cu2+/g hull for modified hulls. The adsorption for the hulls is best described by the Langmuir model, suggesting monolayer, homogeneous adsorption. With a free energy of adsorption of 10.5 +/- 0.9 kJ/mol for unmodified hulls and 14.5 +/-0.4 kJ/mol for modified hulls, the process is categorized as chemisorption for both types of hulls. The adsorption for both hulls is also described by the Redlich-Peterson model, giving beta nearer to 1 than 0, which further suggests homogeneous adsorption described by the Langmuir model. After rinsing the hulls

  2. Aggregation and Deposition of C60 in Aqueous Systems

    EPA Science Inventory

    The extremely low water solubility of many fullerenes precludes aqueous solution processing for engineering applications and minimizes the potential for fullerene environmental effects in aqueous environments. However, studies have shown that C60 fullerene can form stable colloi...

  3. Computer analysis of vibrational spectra of aqueous ethanol solutions

    NASA Astrophysics Data System (ADS)

    Burikov, S. A.; Dolenko, T. A.; Kurchatov, I. S.; Patsaeva, S. V.; Starokurov, Yu. V.

    2012-09-01

    Results of decomposition of vibrational spectra for aqueous ethanol solutions into components in the region of hydroxyl group stretching vibrations are presented. The infrared light absorption and Raman scattering spectra are investigated for alcohol concentrations in the solution changing from 0 to 90 mass %. Methods of higher derivatives and genetic algorithms together with the simplex method are used to investigate the OH stretching vibrational band contour. Independent methods of spectral structure resolution demonstrate good agreement in the number of the major spectral components as well as in the dependences of the peak wavenumbers, band widths, and amplitudes of spectral components on the ethanol concentration in water. The observed changes in the shape of the spectral contour for OH stretching vibration and, therefore, its components are explained in terms of the hydrogen bonding in non-electrolyte/water mixtures.

  4. Indigenous aliphatic amines in the aqueously altered Orgueil meteorite

    NASA Astrophysics Data System (ADS)

    Aponte, José C.; Dworkin, Jason P.; Elsila, Jamie E.

    2015-10-01

    The CI1 Orgueil meteorite is a highly aqueously altered carbonaceous chondrite. It has been extensively studied, and despite its extensive degree of aqueous alteration and some documented instances of contamination, several indigenous organic compounds including amino acids, carboxylic acids, and nucleobases have been detected in its carbon-rich matrix. We recently developed a novel gas chromatographic method for the enantiomeric and compound-specific isotopic analyses of meteoritic aliphatic monoamines in extracts and have now applied this method to investigate the monoamine content in Orgueil. We detected 12 amines in Orgueil, with concentrations ranging from 1.1 to 332 nmol g-1 of meteorite and compared this amine content in Orgueil with that of the CM2 Murchison meteorite, which experienced less parent-body aqueous alteration. Methylamine is four times more abundant in Orgueil than in Murchison. As with other species, the amine content in Orgueil extracts shows less structural diversity than that in Murchison extracts. We measured the compound-specific stable carbon isotopic ratios (δ13C) for 5 of the 12 monoamines detected in Orgueil and found a range of δ13C values from -20 to +59‰. These δ13C values fall into the range of other meteoritic organic compounds, although they are 13C-depleted relative to their counterparts extracted from the Murchison meteorite. In addition, we measured the enantiomeric composition for the chiral monoamines (R)- and (S)-sec-butylamine in Orgueil, and found it was racemic within experimental error, in contrast with the L-enantiomeric excess found for its amino acid structural analog isovaline. The racemic nature of sec-butylamine in Orgueil was comparable to that previously observed in Murchison, and to other CM2 and CR2 carbonaceous chondrites measured in this work (ALH 83100 [CM1/2], LON 94101 [CM2], LEW 90500 [CM2], LAP 02342 [CR2], and GRA 95229 [CR2]). These results allow us to place some constraints on the effects of

  5. Theoretical estimation of the aqueous pKas of thiols

    NASA Astrophysics Data System (ADS)

    Hunter, Nora E.; Seybold, Paul G.

    2014-02-01

    The ionisation state of a compound is a key parameter influencing the compound's activity as a drug, metabolite, pollutant, or other active chemical agent. Sulfhydrol compounds (thiols) tend to be considerably more acidic than their hydroxyl (alcohol) analogues. In this report, quantum chemical approaches previously used for the estimation of the aqueous pKas of alcohols are applied to the estimation of the acidities of thiols. Acidity estimates obtained from the general-purpose SPARC calculational programme (S.H. Hilal, S.W. Karickhoff, and L.A. Carreira, Quant. Struct.-Act. Relat. 14, 348 (1995)) and the ACD/Labs PhysChem Suite v12 programme package are employed as benchmarks. Quantum chemical calculations were performed using both the semiempirical RM1 method and the density functional theory B3LYP/6-31+G* method. The effectiveness of the SM5.4 and SM8 solvent models in estimating the aqueous-phase acidities was also evaluated. All of the approaches examined demonstrated strong correlations with the experimental acidity values.

  6. Opto-electrochemical spectroscopy of metals in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Habib, K.

    2016-03-01

    In the present investigation, holographic interferometry was utilized for the first time to determine the rate change of the electrical resistance of aluminium samples during the initial stage of anodisation processes in aqueous solution. In fact, because the resistance values in this investigation were obtained by holographic interferometry, electromagnetic method rather than electronic method, the abrupt rate change of the resistance was called electrical resistance-emission spectroscopy. The anodisation process of the aluminium samples was carried out by electrochemical impedance spectroscopy (EIS) in different sulphuric acid concentrations (1.0%-2.5% H2SO4) at room temperature. In the meantime, the real time holographic interferometry was used to determine the difference between the electrical resistance of two subsequent values, dR, as a function of the elapsed time of the EIS experiment for the aluminium samples in 1.0%, 1.5%, 2.0%, and 2.5% H2SO4 solutions. The electrical resistance-emission spectra of the present investigation represent a detailed picture of not only the rate change of the electrical resistance throughout the anodisation processes but also the spectra represent the rate change of the growth of the oxide films on the aluminium samples in different solutions. As a result, a new spectrometer was developed based on the combination of the holographic interferometry and electrochemical impedance spectroscopy for studying in situ the electrochemical behavior of metals in aqueous solutions.

  7. Non-oxidative, controlled exfoliation of graphite in aqueous medium.

    PubMed

    Srivastava, Pawan Kumar; Yadav, Premlata; Ghosh, Subhasis

    2016-08-25

    We present a simple, non-oxidative and controlled method to synthesize graphene monolayers by exfoliation in water from different solid carbon sources, such as highly ordered pyrolytic graphite and low density graphite. Any water based method is highly desirable due to several attractive features, such as environmental friendliness, low cost and wide compatibility with other water based processes. We show that thin graphene layers can be exfoliated controllably and reproducibly by varying different parameters during exfoliation in aqueous medium. It has been possible to obtain high quality graphene monolayers with a yield of ∼2.45 wt%, which can be increased up to 16.6 wt% by recycling the sediments. Field effect transistors based on exfoliated graphene monolayers have shown n-type doping and a high carrier mobility of 4500 cm(2) V(-1) s(-1) at room temperature and ∼20 000 cm(2) V(-1) s(-1) at low temperature. Density functional calculations corroborate the infrared spectroscopic results and also indicate that the charge transfer preferentially occurs from water molecules to the graphene sheets resulting in n-type doping. We anticipate that exfoliation of high quality graphene layers in aqueous medium would open up a pathway for various graphene based electronic and biological applications. PMID:27523721

  8. Spectroscopic characterization of both aqueous and solid-state diacerhein/hydroxypropyl-β-cyclodextrin inclusion complexes

    NASA Astrophysics Data System (ADS)

    Petralito, Stefania; Zanardi, Iacopo; Spera, Romina; Memoli, Adriana; Travagli, Valter

    2014-06-01

    Diacerhein, a poorly water soluble antirheumatic prodrug, was spectroscopically characterized to form inclusion complexes with hydroxypropyl-β-cyclodextrin (HPβCD) in both aqueous solution and in solid phase. Complexation with the hydrophilic carriers was used to improve the solubility and dissolution rate of the compound. The kinetics of the prodrug degradation to the active rhein in aqueous buffer solution were also investigated as a function of HPβCD concentration. The solid complexes prepared by different methods such as physical mixture, kneading, co-evaporation method and freeze dried method in 1:1 M ratio, were characterized by DSC and FTIR. The dissolution profiles of solid complexes were determined and compared with diacerhein alone and their physical mixture, in the simulated intestinal fluid at 37 °C. The accurate molecular spectroscopic characterization of diacerhein in the presence of different amounts of aqueous cyclodextrins was essential to determine the correct binding constants for the diacerhein/HPβCD system. The binding constants were also validated by UV spectrometry and HPLC procedure in order to compare the values from the different methods. Higuchi-Connors phase solubility method has proved not suitable when either the free or/and the complexed prodrug degrade in aqueous solution.

  9. 46 CFR 108.474 - Aqueous film forming foam systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Aqueous film forming foam systems. 108.474 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Foam Extinguishing Systems § 108.474 Aqueous film forming foam systems. Aqueous film forming foam systems may be installed if approved by the Commandant....

  10. 46 CFR 108.474 - Aqueous film forming foam systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Aqueous film forming foam systems. 108.474 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Foam Extinguishing Systems § 108.474 Aqueous film forming foam systems. Aqueous film forming foam systems may be installed if approved by the Commandant....

  11. 46 CFR 108.474 - Aqueous film forming foam systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Aqueous film forming foam systems. 108.474 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Foam Extinguishing Systems § 108.474 Aqueous film forming foam systems. Aqueous film forming foam systems may be installed if approved by the Commandant....

  12. 46 CFR 108.474 - Aqueous film forming foam systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Aqueous film forming foam systems. 108.474 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Foam Extinguishing Systems § 108.474 Aqueous film forming foam systems. Aqueous film forming foam systems may be installed if approved by the Commandant....

  13. 46 CFR 108.474 - Aqueous film forming foam systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Aqueous film forming foam systems. 108.474 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Foam Extinguishing Systems § 108.474 Aqueous film forming foam systems. Aqueous film forming foam systems may be installed if approved by the Commandant....

  14. Aqueous alteration on main-belt asteroids

    NASA Astrophysics Data System (ADS)

    Fornasier, S.; Lantz, C.; Barucci, M.; Lazzarin, M.

    2014-07-01

    The study of aqueous alteration is particularly important for unraveling the processes occurring during the earliest times in Solar System history, as it can give information both on the thermal processes and on the localization of water sources in the asteroid belt, and for the associated astrobiological implications. The aqueous alteration process produces the low temperature (< 320 K) chemical alteration of materials by liquid water which acts as a solvent and produces materials like phyllosilicates, sulphates, oxides, carbonates, and hydroxides. This means that liquid water was present in the primordial asteroids, produced by the melting of water ice by heating sources, very probably by ^{26}Al decay. Hydrated minerals have been found mainly on Mars surface, on primitive main-belt asteroids (C, G, B, F, and P-type, following the classification scheme by Tholen, 1984) and possibly also on few transneptunian objects. Reflectance spectroscopy of aqueous altered asteroids shows absorption features in the 0.6-0.9 and 2.5-3.5-micron regions, which are diagnostic of, or associated with, hydrated minerals. In this work, we investigate the aqueous alteration process on a large sample of 600 visible spectra of C-complex asteroids available in the literature. We analyzed all these spectra in a similar way to characterize the absorption-band parameters (band center, depth, and width) and spectral slope, and to look for possible correlations between the aqueous alteration process and the asteroids taxonomic classes, orbital elements, heliocentric distances, albedo, and sizes. We find that 4.6 % of P, 7.7 % of F, 9.8 % of B, 50.5 % of C, and 100 % of the G-type asteroids have absorption bands in the visible region due to hydrated silicates. Our analysis shows that the aqueous alteration sequence starts from the P-type objects, practically unaltered, and increases through the P → F → B → C → G asteroids, these last being widely aqueously altered, strengthening thus

  15. [Investigation of micro-aqueous covalent immobilization of horseradish peroxidase by "conformation memory"].

    PubMed

    Cai, Yixuan; Chen, Junhua; Yao, Dongsheng; Liu, Daling

    2009-12-01

    We has studied the feasibility of preventing protein from denature during covalent immobilization by "conformation memory", which was achieved by freeze-drying under enzyme active conformation and cross-linked with carrier under micro-aqueous media (MAM). Horseradish peroxidase (HRP) and chitosan beads have been used as the model enzyme and carrier. The MAM consisted of 99% dioxane and 1% water. We compared the immobilized HRP under MAM with that under traditional aqueous solvent, found that the optimum temperature of both was raised to 60 degrees C, and the optimum pH was 6.5. However, the MAM-immobilized HRP had shown less activity loss during usage and six times higher activity than that immobilized under aqueous solvent. After 30 min incubation at 70 degrees C, the MAM-immobilized HRP remained 75.42% activity while the aqueous-media-immobilized enzyme only 15.4%. The MAM-immobilized HRP has shown a better operation stability with 77.69% residue activity after 5 times of repeat operation while the aqueous-media-immobilized enzyme only 16.67%. In addition, the MAM-immobilized HRP had also shown more advantages when used in phenol removal. We constructed enzyme electrodes (CS-HRP-SWCNTs/Au) to further display the different properties of the two immobilized HRP. MAM-immobilized HRP-electrode has shown two times stronger response signal to H2O2 than that immobilized under aqueous media, which indicated a better enzyme activity of MAM-immobilized HRP. Our research demonstrated that the conformation memory, to some extent, did contribute to preventing protein from denaturing when use HRP as a model, and it is feasible to immobilize enzyme by covalent cross-linking method under micro-aqueous media.

  16. Study of the blood-aqueous barrier in choroidal melanoma.

    PubMed Central

    Castella, A P; Bercher, L; Zografos, L; Egger, E; Herbort, C P

    1995-01-01

    AIMS--Aqueous flare was used to determine the frequency and amount of blood-aqueous barrier breakdown and correlate it with tumour variables. METHODS--Aqueous flare was analysed prospectively by laser flare photometry in 139 consecutive patients seen in the oncology unit for choroidal melanoma. Both eyes of patients were examined with a laser flare cell meter in a standard fashion. RESULTS--Mean flare difference between healthy and tumour eyes was 3.01 (SD 2.5) photons per millisecond (ph/ms) in 32 cases of small melanomas (p < 0.0001), 10.74 (13.9) ph/ms in 92 cases of medium and large melanomas (p < 0.0001), and 19.23 (11.8) ph/ms in 15 cases of very large melanomas (p < 0.0001). This mean differential flare was significantly higher in medium and large than in small melanomas (p < 0.002) and in very large melanomas than in medium and large melanomas (p < 0.028). A difference of > or = 7 ph/ms between affected and healthy eyes was noted in 70 of 139 melanomas (50.4%). It was found in 3/32 small melanomas (9.4%), in 53/92 medium and large melanomas (57.6%), and in 14/15 very large melanomas (93.3%). CONCLUSION--Multiple linear regression analysis showed that flare was most strongly correlated with tumour volume (r = 0.43; p < 0.0001) and tumour height (r = 0.41; p < 0.0008). PMID:7742283

  17. Search for Aqueous Minerals in Parana Valles, Mars

    NASA Astrophysics Data System (ADS)

    Talib, Saveelah; Dalton, J. B.; Moore, J. M.

    2007-10-01

    Search for Aqueous Minerals in Parana Valles, Mars S. Talib, J.B. Dalton and J.M. Moore We have performed a compositional analysis of surface deposits in Parana Valles using a combination of Mars Observer Laser Altimeter (MOLA), Mars Observer Camera (MOC), Thermal Emission Spectrometer (TES) and Thermal Emission Imaging Subsystem (THEMIS) observations. Parana Valles lies within a well-defined basin in the southern highlands and contains a well-developed watershed drainage network (Barnhart et al., 2007). The strong evidence of hydrologic activity suggests that aqueously-derived minerals may be sufficiently abundant to be detected through orbital remote sensing. We examined MOLA observations to determine locations of smaller basins within Parana, where ponding and sedimentation may have occurred. Mosaics of MOC images were then examined to identify albedo differences which could indicate mineral deposits. THEMIS night-time thermal infrared mosaics were examined to identify regions of high thermal inertia, which may be swept clear of surface dust. Finally, image cubes from TES were compiled. The TES data were culled following the method of Stockstill et al. (2005) to eliminate orbital tracks of high atmospheric dust or water ice cloud composition. A Dust Cover Index (Ruff and Christensen 2002) was computed for TES data and used to reject observations obscured by high surface dust. Once the TES image cube had been reduced, regions of interest were defined based on the areas determined likely to contain minerals of aqueous origin based on the MOLA, MOC, and THEMIS observations. A linear spectral mixture model was then applied to these spectra using the Arizona State University Thermal Emission Spectral Library (Christensen et al., 2000) to estimate mineral abundances. We found that the surface mineralogy of Parana Valles is dominated by mixtures of phyllosilicates, feldspars, olivines and pyroxenes. This is consistent with chemically-weathered basaltic material.

  18. Silicone-containing aqueous polymer dispersions with hybrid particle structure.

    PubMed

    Kozakiewicz, Janusz; Ofat, Izabela; Trzaskowska, Joanna

    2015-09-01

    In this paper the synthesis, characterization and application of silicone-containing aqueous polymer dispersions (APD) with hybrid particle structure are reviewed based on available literature data. Advantages of synthesis of dispersions with hybrid particle structure over blending of individual dispersions are pointed out. Three main processes leading to silicone-containing hybrid APD are identified and described in detail: (1) emulsion polymerization of organic unsaturated monomers in aqueous dispersions of silicone polymers or copolymers, (2) emulsion copolymerization of unsaturated organic monomers with alkoxysilanes or polysiloxanes with unsaturated functionality and (3) emulsion polymerization of alkoxysilanes (in particular with unsaturated functionality) and/or cyclic siloxanes in organic polymer dispersions. The effect of various factors on the properties of such hybrid APD and films as well as on hybrid particles composition and morphology is presented. It is shown that core-shell morphology where silicones constitute either the core or the shell is predominant in hybrid particles. Main applications of silicone-containing hybrid APD and related hybrid particles are reviewed including (1) coatings which show specific surface properties such as enhanced water repellency or antisoiling or antigraffiti properties due to migration of silicone to the surface, and (2) impact modifiers for thermoplastics and thermosets. Other processes in which silicone-containing particles with hybrid structure can be obtained (miniemulsion polymerization, polymerization in non-aqueous media, hybridization of organic polymer and polysiloxane, emulsion polymerization of silicone monomers in silicone polymer dispersions and physical methods) are also discussed. Prospects for further developments in the area of silicone-containing hybrid APD and related hybrid particles are presented.

  19. Hydrogeologic controls on induced seismicity in crystalline basement rocks due to fluid injection into basal reservoirs.

    PubMed

    Zhang, Yipeng; Person, Mark; Rupp, John; Ellett, Kevin; Celia, Michael A; Gable, Carl W; Bowen, Brenda; Evans, James; Bandilla, Karl; Mozley, Peter; Dewers, Thomas; Elliot, Thomas

    2013-01-01

    A series of Mb 3.8-5.5 induced seismic events in the midcontinent region, United States, resulted from injection of fluid either into a basal sedimentary reservoir with no underlying confining unit or directly into the underlying crystalline basement complex. The earthquakes probably occurred along faults that were likely critically stressed within the crystalline basement. These faults were located at a considerable distance (up to 10 km) from the injection wells and head increases at the hypocenters were likely relatively small (∼70-150 m). We present a suite of simulations that use a simple hydrogeologic-geomechanical model to assess what hydrogeologic conditions promote or deter induced seismic events within the crystalline basement across the midcontinent. The presence of a confining unit beneath the injection reservoir horizon had the single largest effect in preventing induced seismicity within the underlying crystalline basement. For a crystalline basement having a permeability of 2 × 10(-17)  m(2) and specific storage coefficient of 10(-7) /m, injection at a rate of 5455 m(3) /d into the basal aquifer with no underlying basal seal over 10 years resulted in probable brittle failure to depths of about 0.6 km below the injection reservoir. Including a permeable (kz  = 10(-13)  m(2) ) Precambrian normal fault, located 20 m from the injection well, increased the depth of the failure region below the reservoir to 3 km. For a large permeability contrast between a Precambrian thrust fault (10(-12)  m(2) ) and the surrounding crystalline basement (10(-18)  m(2) ), the failure region can extend laterally 10 km away from the injection well.

  20. Simulating Thermal-Hydrologic-Mechanical-Chemical Evolution Surrounding Fluid Injection in a Fractured Porous Geothermal Reservoir

    NASA Astrophysics Data System (ADS)

    Taron, J.; Min, K.; Elsworth, D.

    2006-12-01

    Computational analysis is conducted on the coupled thermal-hydrologic-mechanical-chemical (THMC) behavior of a stimulated EGS geothermal reservoir. Numerical analyses utilize a newly developed simulator capable of examining THMC processes in fractured porous geologic media. The simulator links the thermal-hydrologic- chemical (THC) computational code TOUGHREACT with the mechanical (M) capability of FLAC3D, where the response of pore fluid pressure to mechanical disturbance is treated as an undrained system and mineral precipitation/dissolution generates porosity and permeability change within each dual-permeability continuum. Non-linear permeability response to thermal-hydrologic-mechanical (THM) mechanisms is accommodated via embryonic mechanical and transport constitutive laws, and is considered to act in union with permeability changes associated with the removal or addition of minerals within the system. This construct is applied to the geometry of an injector-withdrawal doublet within the Coso Geothermal field, where in situ stress conditions, thermal state, and mineralogical composition at 3000m depth are extracted from recorded field data. Initial results for feasible parametric settings show that permeability reduction in the vicinity of a cool (80°C) injection well may be significant, within an order of magnitude, and accompanied by large (MPa) changes in the stress field throughout the reservoir for imposed boundary conditions of constant stress.